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  • IPEN-DOC 28004

    SAHYUN, ADELIA ; PEREZ, CLARICE A.. Real time tracking of mobile radioactive sources. In: INTERNATIONAL CONGRESS OF THE INTERNATIONAL RADIATION PROTECTION ASSOCIATION, 15th, January 18 - February 5, 2021, Seoul, Korea; Online. Seoul, 2021. p. 857-857.

    Abstract: It is vital that mobile radioactive sources remain under safe and secure control, at all times and the operator is notified in real time of their unauthorised removal from a fixed location, store or vehicle. This paper describes a system that constanily monitors mobile radioactive sources and provides a means to detect their location should unauthorised removal occur. Thousands of radiographic exposure devices are transported in the public domain every day and there are examples where the vehicle carrying a device has been stolen, not for the device itself but for the vehicle, which often leads to the device being discarded. Abandoning the device can lead to high risks of exposure for those who have secondary contact for example children or those attracted by its perceived intrinsic value. A lack of knowledge of the dangers of radiation has led some people in the past attempting and sometimes succeeding to open a device and remove the source. With other factors involved such as location, country and the intentions of those in possession of the device, it is therefore important that the device is located quickly, enabling recovery actions to begin as soon as possible. In addition, this paper encourages that such monitoring systems are more widely promoted in all countries and that an international code of practice is developed to assist when sources are transported internationally.

    Palavras-Chave: radiation sources; radiation monitoring; security; radiation protection

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  • IPEN-DOC 28003

    PEREZ, CLARICE de F.A.; SAHYUN, A. . ALARA in focus. In: INTERNATIONAL CONGRESS OF THE INTERNATIONAL RADIATION PROTECTION ASSOCIATION, 15th, January 18 - February 5, 2021, Seoul, Korea; Online. Seoul, 2021. p. 645-645.

    Abstract: By the 1950s the world had already realized the need to protect the people from the harmful effects of ionizing radiation. In 1955 ICRP established an incipient dose limitation system that has since been refined over the years. The development of the fundamental philosophy was completed in the ICRP Publication 26, in 1977, where the three principles of the dose limitation system were established and identified separately. The principles are known as: (a) justification, (b) optimization or (ALARA) As Low As Reasonably Achievable, and (c) dose limitation. The philosophy contained in Publication 26 was adopted by the IAEA in its Safety Series publication No. 9, 1982 edition, and in Brazil by the National Nuclear Energy Commission in 1988, with the publication of the regulations CNEN-NE3.01. The three principles remain valid and in the current editions of both documents. This paper describes the development of the ALARA concept from its origin to the present day, to provide an insight and understanding of its meaning and importance for the new generations of Radiation Protection Supervisors and other professionals who work directly and indirectly in areas that involve the use of ionizing radiation.

    Palavras-Chave: alara; radiation protection; radiation doses; security; dose limits

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  • IPEN-DOC 28002

    LEVY, DENISE ; SORDI, GIAN M.A.A. . Risk perception and risk acceptance: the need of effective communications to fill the critical gaps between society and the scientific community. In: INTERNATIONAL CONGRESS OF THE INTERNATIONAL RADIATION PROTECTION ASSOCIATION, 15th, January 18 - February 5, 2021, Seoul, Korea; Online. Seoul, 2021. p. 116-116.

    Abstract: Effective nuclear science communications can inform people about benefits and risks, allowing them to make decisions and choices. Nevertheless, regarding radiological protection, controversies and misinformation distort public's perceptions of radiation risks. This paper offers an overview of ineffective mass media communication and its impacts on citizens' perceptions of nuclear technology. There seem to be a gap between society and the scientific community. The general public do not read high-specialized articles written by scientists. In Knowledge Society, where Internet and social media are the most common source of information, opinion makers seem to privilege sensationalistic rumors about the harmful effects of ionizing radiation, environment contamination and accidents. Moreover, available information about the biological effects of the exposure to ionizing radiation confuse public's perceptions of radiation risks and benefits. Whether experts agree that radiation causes observable health effects at high doses, Intemet highlights controversies on the biological effects of low-dose radiation. Internet reports that the exposure to indoor radon is a risk factor for lung cancer. Intemet reports that the radioactive monazitic sand brings health benefits. It is not easy for the general public to understand contradictions and to identify reliable sources. This article presents and discusses examples of pseudo-scientific information, newspapers errors, fake news, and anti-nuclear didactic material, where basic concepts are mamipulated, and omission of vital information leads the public to mistrust and fear. Unfounded prejudices, misconceptions and misinformation are delivered in TV news, Intemet articles, social media, TV series, cartoons and even through science journals. The general public, most often, do not have trustful information about radiological protection regulations and recommendations regarding human health, environment protection, management of radioactive waste or safe transport of radioactive material. Finally, this paper emphasizes the importance for scientists to be able to communicate to the public developing science-based communication programs, evaluating the adequacy of those communications, investing in properly scientific divulgation about the risks and benefits of nuclear sciences that impact in citizens' everyday hfe, such as medical applications, industrial applications, public safety and nuclear power generation. The balance between risk perception and risk acceptance depends on effective, trustworthy and understandable mformation. It is essential to educate educators and opinion-makers, combating fake pseudo-scientrfic information, social networks sensationalism and omissions of the media.

    Palavras-Chave: radiation protection; risk assessment; public opinion; information dissemination; public information; nuclear energy; radioactivity

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  • IPEN-DOC 27996

    LIMA, CASSIO ; CORREA, LUCIANA; BYRNE, HUGH; ZEZELL, DENISE M. . Influence of the reference spectrum used as input to the RMieS-EMSC algorithm for correction of spectral distortions induced by Mie scattering in FTIR hyperspectral images. In: SBFOTON INTERNATIONAL OPTICS AND PHOTONICS CONFERENCE, October 7-9, 2019, São Paulo, SP. Abstract... Piscataway, NJ, USA: IEEE, 2019. p. 47-48.

    Abstract: Fourier transform infrared (FTIR) microspectroscopy has shown great promise as a tool to assess the histological architecture of tissue samples by providing morphochemical maps that enable the evaluation of both spatial and compositional information based on the signatures of molecular vibrations. However, FTIR datasets collected in transmission and transflection modes are subjected to undesired spectral contributions non-related to the phenomenon of light absorption that must be corrected prior any analysis. The algorithm so-called “Resonant Mie Scattering – Extended Multiplicative Scatter Correction (RMieS-EMSC)” has been well succeeded in vibrational spectroscopy in removing spectral distortions. The main idea of the algorithm is to reconstruct the datasets that present undesired spectral contributions based on a scatter-free reference spectrum. In this study, FTIR hyperspectral images acquired from cutaneous malignant lesions were submitted to RMieS-EMSC protocol using Matrigel and average spectrum in order to evaluate the influence of the reference spectrum in the final correction. False-color maps obtained after segmentation were compared in terms of image quality and consistency with standard histopathology in order to evaluate the ability of each method to reproduce the histological structures of the specimen. Our findings indicate that the choice of reference spectrum has very little difference on the outcome of image analysis. The images obtained by both spectra used as reference may not have resulted in identical false-color maps, but the differences between the morphochemical maps are relatively small.

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  • IPEN-DOC 27995

    MACHADO, NEILA; SATO, ERIKA; BORTOLETTO, DAIANA; LIMA, CASSIO ; ZEZELL, DENISE M. ; MARTINHO, HERCULANO. Computational models for light-tissue interactions: recent advances. In: SBFOTON INTERNATIONAL OPTICS AND PHOTONICS CONFERENCE, October 7-9, 2019, São Paulo, SP. Abstract... Piscataway, NJ, USA: IEEE, 2019. p. 26-26.

    Abstract: Computational simulations could be used as a tool to better understand how biochemical changes translate into structural changes that generate pathological states. By computational calculations, it is possible to obtain the vibrational spectrum of molecules and macromolecules. It is possible to verify which atoms or molecules contribute to the existence of each characteristic vibrational mode, identify and interpret the interactions between these modes, and associate these pieces of information to the pathological processes. In this work we will present recent advances from our group by using density functional theory (DFT) to model normal, inflammatory, and tumoral tissues in a minimalist way (100 atoms). Comparison with experimental data (vibrational spectroscopy data) will also be presented. Perspectives on using molecular dynamics on large models (> 60,000 atoms) will also be discussed.

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  • IPEN-DOC 27994

    CASTRO, PEDRO ; LIMA, CASSIO ; ZORN, TELMA; ZEZELL, DENISE M. . Assessment of burn wounds status using mid-infrared spectroscopy. In: SBFOTON INTERNATIONAL OPTICS AND PHOTONICS CONFERENCE, October 7-9, 2019, São Paulo, SP. Abstract... Piscataway, NJ, USA: IEEE, 2019. p. 20-21.

    Abstract: Burns are one of the major causes of morbidity and the most costly traumatic injuries worldwide. Better understanding of the molecular mechanisms associated with wound healing might provide improved clinical strategies to speed up the tissue repair process and reduce the global impact of burns on public health services. The traditional techniques used to assess the biochemical events related to wound repair are laborious, time-consuming and require multiple staining. Thus, the present study aims to evaluate the feasibility of Fourier transform infrared (FTIR) spectroscopy in order to monitor the progress and healing status of burn wounds. Third-degree burn injuries were induced on Wistar rats by water vapor exposure. Afterwards, biopsies specimen was extracted for further histopathological examination and spectroscopic evaluation at 4 time-points (3, 7, 14 and 21 days). Raw spectral data were offset-corrected and normalized by amide I band area. The second derivatives were compared by the Principal Component Analysis (PCA). On days 3 and 7, when compared to healthy group, biomolecules bands were most prominent. However, on days 14 and 21, these molecular bands decreased. Therefore, our pairwise comparison revealed that metabolic activity induced by thermal injury decreases as the healing process progresses. Our findings show that FTIR spectroscopy can monitor the biochemical development induced by burn injury and detect the status of wound repair.

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  • IPEN-DOC 27988

    CACHEFFO, A.; LOPES, F.J.S. ; YOSHIDA, A.C.; LANDULFO, E. . Classifying aerosols with machine learning techniques using the AERONET and CALIPSO satellite databases. In: SP SCHOOL OF ADVANCED SCIENCE ON ATMOSPHERIC AEROSOLS, July 22 - August 2, 2019, São Paulo, SP. Abstract... São Paulo, SP: Instituto de Física - USP, 2019. p. 102-102.

    Abstract: In this work, our intention is to develop ways to correlate and classify several types of aerosols, by practical and objective manners, with the aim of machine learning techniques (specially decision trees and random forests) [1, 2]. For this purpose, we are intended to use the AERONET (Aerosol Robotic Network) and CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) satellite databases [3]. The AERONET database, which includes measurements made since year 2000, will provide to us a reference standard for the categorization and classification of aerosols present in atmosphere [3]. Following this, the databases for the measurements made by the CALIPSO satellite will be addressed, also with the objective of categorizing and classifying aerosols. Such data mining processes will enable us to carry out statistical and climatological analyzes of these databases, allowing a better study of the atmospheric behavior of aerosols in the Earth’s atmosphere [4]. We believe that the development of such tools and techniques for treatment of data provided by AERONET and CALIPSO will contribute greatly to a better understanding of climate change processes on Earth, a subject of scientific interest, especially in recent years.

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  • IPEN-DOC 27987

    OLIVEIRA, D.C.; HOELZEMANN, J.J.; LANDULFO, E. ; ARBOLEDAS, L.A.. Aerosol optical properties in the atmosphere of Natal/Brazil measured a sun photometer of the AERONET. In: SP SCHOOL OF ADVANCED SCIENCE ON ATMOSPHERIC AEROSOLS, July 22 - August 2, 2019, São Paulo, SP. Abstract... São Paulo, SP: Instituto de Física - USP, 2019. p. 95-95.

    Abstract: The study of atmospheric aerosols contributes to the understanding of radiative forcing and global warming. In addition, aerosols may influence visibility, acid rain, human health and precipitation. Since 2016, Natal, capital of Rio Grande do Norte, Brazil, has a solar photometer (CIMEL) of the RIMA-AERONET network that can identify the presence of biomass burning aerosols and desert dust from Africa. For this identification, it is aimed to characterize the optical properties of these aerosols present in the atmosphere of Natal (RN). The data available by AERONET, at level 1.5, Version 3, provide information on some microphysical characteristics such as Optical Aerosol Depth (AOD), Ångström coefficient ( ), Single Scattering Albedo (SSA), Asymmetry Factor (g), Complex Refractive Index (N), Volume Size Distribution (VSD) and Precipitable Water. The data collection period was from August 2017 to August 2018. Aerosols were classified based on global climatologies and their optical properties were described. Observations were compared with daily measurements from satellites and the local LIDAR over the course of a day for a case study. In addition, backward trajectories were modeled with the HYSPLIT model to verify the predominant origin of the air masses. Aerosols present in the atmospheric column of Natal showed monthly means of AOD in the range of 0.10 to 0.15 with peak of 40%, monthly means of between 0.6 and 0.8 with peak above 30%, bimodal DTV with dominant coarse mode, SSA about 0.8, real part around 1.5, imaginary part raging from 0.0125 to 0.0437 and g above 0.74. The Precipitable Water accompanied the increase of the precipitation for the months of December, January, February and March. The classification identified mixed aerosols (60.40%), marine aerosols (30.69%) and mineral dust (8.91%). The backward trajectories showed that in 51% of the cases the continental aerosols origined from the Africa.

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  • IPEN-DOC 27986

    CORREA, T. . Determination of CH4 in mangrove area using LIDAR Raman and Cavity Ringdown Laser Spectroscopy. In: SP SCHOOL OF ADVANCED SCIENCE ON ATMOSPHERIC AEROSOLS, July 22 - August 2, 2019, São Paulo, SP. Abstract... São Paulo, SP: Instituto de Física - USP, 2019. p. 79-79.

    Abstract: Natural wetlands are considered important sources of atmospheric methane, and several researchers have attempted to quantify global emissions from wetland environments. Therefore, this project was conducted an experimental data sample in Itanhaém region, which explored the spatial variability of methane flow within a system with no anthropogenic wetland impact known as mangrove. The study area is located in the coastal region of São Paulo state, region of Atlantic Forest preservation, with large mangrove area. Since remote sensing is a method non-invasive, we were able to detect the emission of methane in areas that do not undergo human intervention, estimating the release of natural gas. The Lidar Raman method reduce the complexity system and cost of mobile and real-time analytics. The system used includes a commercial laser pulsed Nd:YAG Quantel S.A., model CFR 200, with wavelengths of 355 nm, 353 nm and 396 nm, 120 mJ pulse power, with laser repetition rate of 20 Hz and pulse width of 20 s, with a spatial resolution of 7.5 m. The system includes an ethernet interface, used together with LabView software to control the measurement and readout of the acquired data. For an exchange and precision data the Cavity Ringdown Laser Spectroscopy (CRDS) was used functioned with light absorbing at specific wavelengths and its ability to detect mole fractions in ppt (part per trillion) detecting small amounts of gases. Advances in CRDS in cavity-enhanced absorption spectroscopy techniques provide dramatic increases in optical path length and, as a result, allow ultra-sensitive trace gas measurements using robust, reliable and near-infrared temperature room-temperature diode lasers. The results indicated that the spatial variability of the flow within a wetland ecosystem can introduce significant results when compared to areas with impacts with fugitive gases, as well as in extrapolations to larger areas, even if the extension of the ecosystem is well known.

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  • IPEN-DOC 27985

    ANDRADE, I. da S. ; LANDULFO, E. ; ARAUJO, E.C. ; MENDONCA, F. de M. ; SALANI, M.H.G. de A. ; CORREA, T. ; MARQUES, M.T. ; COSTA, R.F. da; GUARDANI, R.. Analysis of the dispersion of aerosol in Cubatão-SP using remote sensing techniques. In: SP SCHOOL OF ADVANCED SCIENCE ON ATMOSPHERIC AEROSOLS, July 22 - August 2, 2019, São Paulo, SP. Abstract... São Paulo, SP: Instituto de Física - USP, 2019. p. 78-78.

    Abstract: Aerosls are emitted by a several sources, these can be antropogenic – emitted by human activities - or natural.Their sudies are an important, because its impacts on the dynamics of the Earth’s atmosphere are huge. The study area have one of the most important industrial complex in the state of Sao Paulo. In the past the city of Cubatão was known as “death valey”, due to the environmental problems caused by the high levels of pollutants that was emitted by the industries. Following this event, regulatory laws on atmospheric emissions were developed, both at the state and federal levels. Today, although Cubatão has lower levels of pollution and controlled industrial emissions, but it is possible to observe overcoming air quality standards. Based on the presented context, the present work aims to conduct a study of the dispersion of aerosols in the region of Cubatão-SP using several techniques, such as: remote sensing (elastic lidar and wind lidar), satellite data, air quality information and also simulations of air masses using a model.

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  • IPEN-DOC 27984

    MACEDO, F. . Correlation between two different real time data acquisition systems: LIDAR Raman and Cavity Ringdown Laser Spectroscopy, for CH4 as a fugitive gas, in São Paulo Metropolitan Area. In: SP SCHOOL OF ADVANCED SCIENCE ON ATMOSPHERIC AEROSOLS, July 22 - August 2, 2019, São Paulo, SP. Abstract... São Paulo, SP: Instituto de Física - USP, 2019. p. 77-77.

    Abstract: Fugitive emissions, defined as unintended or irregular leaks of gases and vapors, are an important source of air pollution that is difficult to monitor and control. These sites, including megacities like São Paulo, are growing in size and economic activity. At the same time, there is a remarkable growth in concerns about the environmental issues associated with these activities. In a constantly changing world, with increasing concentrations of greenhouse gases (GHGs), among them methane (CH4) and volatile organic compounds (VOC), mitigation of atmospheric emission of these gases to contain global warming, make field campaigns in the metropolitan region of São Paulo very relevant. Optical remote sensing techniques as lidar can attend the need for real time and trustable information on fugitive emissions. The Cavity Ringdown Laser Spectroscopy (CRDS) technique was adopted because it is widely used in the detection of gas samples that absorb light at specific wavelengths and also for their ability to detect mole fractions up to the parts per trillion level. The Raman LIDAR system used includes a commercial laser pulsed Nd:YAG Quantel S.A., model CFR 200, with wavelengths of 355 nm, 353 nm and 396 nm, 120 mJ pulse power, with laser repetition rate of 20 Hz and pulse width of 20 s, with a spatial resolution of 7,5 m. The system includes an ethernet interface, used together with LabView software to control the measurement and readout of the acquired data. The mixing ratio of CH4 can be observed within the planetary boundary layer. The measured methane profiles correlate with the acquisitions made with the CRDS, however, an additional contribution of control data in which the Raman lines detect with high sensitivity.

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  • IPEN-DOC 27983

    BEU, C. . Atmospheric dispersion comparative study between a typical and a disturbed PBL using a doppler lidar. In: SP SCHOOL OF ADVANCED SCIENCE ON ATMOSPHERIC AEROSOLS, July 22 - August 2, 2019, São Paulo, SP. Abstract... São Paulo, SP: Instituto de Física - USP, 2019. p. 73-73.

    Abstract: An atmospheric dispersion study was conducted for 2 different synoptical conditions for a hypotetical nuclear accident: the first is a pre-frontal condition with a typical Planetary Boundary Layer (PBL) and the second is a disturbed PBL due to a synoptic though. The site is a complex terrain area (Ipero - Brazil), where the topography modulates the circulation and the Low Level Jet (LLJ) is a common feature of the PBL. For one year a doppler lidar retrieved the wind vertical profile at Ipero, allowing to evaluate datasets that can be used as input data for the Atmospheric Transport and Dispersion Models (ATDM). Of the 3 datasets evaluated, only GDAS reproduced the LLJ and was chosen for running the HYSPLIT4 ATDM experiments.

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  • IPEN-DOC 27982

    NASCIMENTO, CARLOS E. ; SALES, TATIANE da S.N. ; CARBONARI, ARTUR W. . Investigation of HfO2 and ZrO2, separately and also in the form of mixtures, pure and doped with Si. In: INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, February 10-15, 2019, Goa, India. Abstract... Mumbai, India: Tata Institute of Fundamental Research, 2019. p. 85-85.

    Abstract: The HfO2 has been used in several technological applications, one of which is the replacement of silicon oxide as the material for the door in the manufacture of CMOS-FET devices [1]. ZrO2 also has several applications, being more used in the form of solid electrolytes and oxygen sensors and also in electrochemical pumps. Due to the similarity of the size and properties, that is found in the proportion of 1 to 2 % in the ore of this one. Since the ions of these elements are nearly identical in size, the separation is difficult, and is in most cases unnecessary due to the similarity of its properties [2]. Doping with other elements improves the specific characteristics of HfO2 and ZrO2, making them useful for different applications and extending their uses in CMOS-FET devices. It also reduces the ZrO2 defects, such as its low resistance to high temperatures, causing in the formation of polycrystalline films and decreasing the dielectric constant that can occur due to leakage current in the grain boundaries, making it necessary to use an amorphous interface to reduce losses. In addition, grain size and orientation change throughout a polycrystalline film, which can cause variations in the value of producing irreproducible properties [3]. In this project the atomic scale investigation of HfO2 and ZrO2 was carried out separately and also in the form of pure, doped mixtures with Si [4]. They were used (RBS), X-ray Diffraction [5] and SEM for caracterization. The PAC technique was used to measure the hyperfine parameters, such as the electric field gradient (Vzz), the asymmetric parameter of the electric field gradient (η) and the possible magnetic hyperfine field over a wide temperature range (from 10 to 1300 K). The measurements were performed in order to correlate the results with the behavior of the characteristic properties of each compound to understand the microscopic mechanisms that give rise to these phenomena [6].

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  • IPEN-DOC 27981

    LEITE NETO, O.F.S. ; SANTOS, B.S. ; NARESSI, A.L.E. ; SALES, T.S.N. ; SAXENA, R.N. ; CARBONARI, A.W. . Study of hyperfine interactions in Perovskite structure CaTiO3 with perturbed angular correlation spectroscopy. In: INTERNATIONAL CONFERENCE ON HYPERFINE INTERACTIONS AND THEIR APPLICATIONS, February 10-15, 2019, Goa, India. Abstract... Mumbai, India: Tata Institute of Fundamental Research, 2019. p. 84-84.

    Abstract: Ceramic materials of the perovkista were identified as candidates for immobilization of medium and high levels of radioactive waste due to the fact that they are thermodynamically chemically and physically stable. Because it is a nuclear technique, PAC spectroscopy has great precision and efficiency in the measurement of local hyperfine fields on an atomic scale, constituting an ideal tool for the investigation of the atomic origin of structural phenomena, such as the influence of defects in the macroscopic properties of many materials or the local neighborhood of metallic atoms in the oxide structure. The samples has been prepared by sol-gel method and characterized by X-ray diffraction. In this study the time differential perturbed angular correlation (PAC) spectroscopy was used to study the structure of CaTiO3 and the possible defects made by radiation exposure. The probe nucleus used in this research was 111Cd. The PAC method is based on the hyperfine interaction of nuclear moments of the probe with extra nuclear magnetic fields or electric field gradients (EFGs). In the case of quadrupolar electric interaction, the experimental measurement gives the quadrupolar frequency νQ with respective distribution δ as well as the asymmetry parameter η of EFG. The γ-γ PAC measurements were carried out using a standard set up with four conical BaF2 detector scintillators with a time resolution of 0.6 ns (FWHM).

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  • IPEN-DOC 27980

    MATOS, B.R. ; SILVA, J.S. da ; SCHADE, U.; PUSKAR, L.; FONSECA, F.C. . Identification of the polymer and electrode polarizations of Nafion dielectric spectrum. In: WORKSHOP ON ION EXCHANGE MEMBRANES FOR ENERGY APPLICATIONS, June 25-27, 2019, Bad Zwischenahn, Germany. Abstract... 2019.

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  • IPEN-DOC 27979

    MATOS, B.R. ; FONSECA, F.C. . Nafion dielectric polarization effects on the fuel cell I-V curve. In: WORKSHOP ON ION EXCHANGE MEMBRANES FOR ENERGY APPLICATIONS, June 25-27, 2019, Bad Zwischenahn, Germany. Abstract... 2019.

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  • IPEN-DOC 27976

    MORAES, L.P.R. ; MEI, J.; MARANI, D.; FONSECA, F.C. ; SUN, Z.. Wet-chemical synthesis of CeO2 for electrochemical applications. In: INTERNATIONAL CONFERENCE ON HIGH-PERFORMANCE CERAMICS, 11th, May 25-29, 2019, Kunming, China. Abstract... 2019.

    Abstract: Nanostructured metal oxides have been extensively studied in the last decades for their physicochemical properties, which depend on the size and shape of their nanostructures. The same chemical element or compound can exhibit different properties in different shapes and dimensions. Metal oxides are a class of inorganic compounds very important in many areas of materials science due to their unique properties that enable them to have a wide range of applications, such as sensor, catalysis, ceramics, absorbents and superconductors. They are particularly attractive for electrochemical applications due to their low molecular weight, favorable electrochemical properties and low toxicity, and have been extensively studied for the development of new energy conversion and storage systems, especially because of the higher electrode surface area, leading to higher charge/discharge rates, and their rich redox reactions involving different ions. Particularly, CeO2 is a promising metal oxide as it can present defects such as oxygen vacancies which play an important role for catalytic, magnetic and electrochemical properties. In this work, different nanostructures of CeO2 were synthesized by the selfassembly approach, from molecular precursors, using Pluronic P123 as surfactant and ethylene glycol as co-surfactant in ethanol solvent in a solvothermal system. The effect of different synthesis parameters on the morphology, crystallite size and electrochemical properties were investigated via various analytical techniques. The experimental results indicated that the synthesis parameters, such as temperature, aging time and chemicals concentration, strongly influences the morphology and sizes of CeO2, thus enabling the intentionally design of different nanomaterials.

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  • IPEN-DOC 27975

    FONSECA, FABIO C. ; MACHADO, MARINA F.S. ; MORAES, LETICIA P.R. ; RODRIGUES, THENNER S. ; KABIR, AHSANUL; MARANI, DEBORA; VAN NONG, NGO; ESPOSITO, VINCENZO. Controlling the sintering of ceria by shape-controlled synthesis of nanoparticles. In: INTERNATIONAL CONFERENCE ON HIGH-PERFORMANCE CERAMICS, 11th, May 25-29, 2019, Kunming, China. Abstract... 2019.

    Abstract: The influence of surface energy of Gd-doped CeO2 nanometric crystals with different morphologies on mass diffusion mechanisms is studied. Depending on the starting morphology (nanocubes, nanorods, and random nanoparticles) extremely different microstructures, ranging from rapidly densified to thermodynamically stable porous structures. We investigate Gd-doped ceria (10% molar, GDC) both for its relevance in several chemical, environmental and energy technologies, and because the extensive knowledge on diffusion effects ruling this compound. We synthesized GDC as nanocubes (NC) and nanorods (NR) by a hydrothermal method whereas randomly oriented nanoparticles (RD) were obtained by co-precipitation. All samples were measured as single phase GDC powders with narrow nanoparticle size distributions. The high surface area NR exhibit lower green density as compared to NC. Dilatometric analyses revealed that NR have a pronounced linear retraction starting at low temperatures (~200°C) with maximum sintering activity at ~1100°C. High surface energy in NRs leads to a rapid rod to sphere transformation as well as to a rapid densification despite relatively low green density. On the other hand, the solid state diffusion in NCs is significantly inhibited, as confirmed by the highly porous microstructure of sintered samples. The results indicated the possibility of controlling microstructure of GDC by defining the shape of nanoparticles for different application in which dense or stable pores are required.

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  • IPEN-DOC 27974

    IZIDORO, JULIANA ; FUNGARO, DENISE ; CAMPELLO, FELIPE ; GUILHEN, SABINE . Column leaching test for the evaluation of immobilization of toxic elements in modified coal fly ash. In: INTERNATIONAL WORKSHOP ADVANCES IN CLEANER PRODUCTION, 8th, November 13-15, 2019, Sanya, China. Abstract... São Paulo, SP: Advances in Cleaner Production Network, 2019. p. 64-65.

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  • IPEN-DOC 27972

    NASCIMENTO, F.C. ; CALVO, W.A.P. . Proposal of LCA and Circular Economy concepts in the application, properties development and improvement from a premium acrylic emulsion added with aqueous dispersions of cellulosic residues treated by electron beam. In: INTERNATIONAL MEETING ON RADIATION PROCESSING, 19th, April 1-5, 2019, Strasbourg, France. Resumo expandido... 2019.

    Palavras-Chave: life cycle assessment; electron beams; paints; cellulose; aqueous solutions

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  • IPEN-DOC 27966

    IZIDORO, JULIANA de C. ; BIBIANO, RAMIRO H. das N. ; LIMA, DANIELE de A.V. ; FUNGARO, DENISE A. . Gestão de resíduos sólidos agroindustriais e obtenção de produtos de valor agregado: uma perspectiva de desenvolvimento sustentável. In: SEMINÁRIO SAÚDE PLANETÁRIA NA AMÉRICA LATINA, 15-16 de dezembro, 2020, Online. Resumo... 2020.

    Abstract: As atividades da agroindústria estão gerando grandes quantidades de resíduos devido aos processos produtivos e alto padrão de consumo da sociedade. A maioria desses resíduos é descartada por queima, despejo ou aterramento causando impactos ambientais e na saúde humana. O conceito de aproveitamento de resíduos como componente da economia circular é uma alternativa para a disposição inadequada. A valorização de resíduos envolve a determinação das características físico-químicas por diferentes técnicas (FRX, DRX, MEV, etc). A etapa posterior consiste na aplicação de processos que transformam o resíduo em material de valor agregado. As cinzas provenientes da queima do bagaço da cana-de-açúcar são um dos principais resíduos gerados no Brasil. O alto teor de sílica possibilita a obtenção de silicato de sódio, nanosílica e zeólita. Esses produtos foram aplicados como material adsorvente e na produção de filmes biodegradáveis de amido. Resíduos lignocelulósicos (serragem, endocarpo de Macaúba) foram convertidos em biocarvão. As suas principais aplicações são como adsorvente e precursor de carvão ativado, além de apresentar potencial para o melhoramento das características ambientais de telhado verde. Dentre os resíduos inorgânicos, os produtos da combustão de carvão, compostos por sílica e alumina, são matéria-prima para obtenção de nanomateriais adsorventes como zeólita de alta pureza e tobermorita. Da mesma forma, o resíduo da reciclagem de alumínio pode ser usado na síntese de zeólita. A composição das cinzas sulfatadas geradas no processo úmido de dessulfurização indica seu potencial como aditivo no cimento e na formação de geopolímeros. Nessa abordagem, a adoção da economia circular na gestão de resíduos contribui significativamente para o cumprimento dos Objetivos de Desenvolvimento Sustentável (ODSs), especificamente, ODS 12: “Até 2030, reduzir substancialmente a geração de resíduos por meio da prevenção, redução, reciclagem e reuso”.

    Palavras-Chave: agricultural wastes; waste management; sustainable development; solid wastes

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  • IPEN-DOC 27965

    LOPES, FABIO ; YOSHIDA, ALEXANDRE ; CACHEFFO, ALEXANDRE ; SILVA, JONATAN ; MOREIRA, GREGORI ; LANDULFO, EDUARDO . Validation of AEOLUS L2A products using a multiwavelength lidar system at SPU Lidar Station - Brazil. In: AEOLUS CAL/VAL AND SCIENCE WORKSHOP, November 2-6, 2020, Online. Apresentação... 2020.

    Palavras-Chave: optical radar; aerosols; layers; earth atmosphere; wave propagation; satellite atmospheres

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  • IPEN-DOC 27962

    APITULEY, ARNOUD; KREHER, KARIN; PITERS, ANKIE; SULLIVAN, JOHN; VAN ROOZENDAEL, MICHEL; VLEMMIX, TIM; DEN HOED, MIRJAM; FRUMAU, ARNOUD; HENZING, BAS; SPEET, BART; VONK, JAN; VEEFKIND, PEPIJN; ALVES, DIEGO ; CACHEFFO, ALEXANDRE ; STEIN-ZWEERS, DEBORAH; ALLAART, MARC; ESKES, HENK; VAN DER ENT, FLORIS; SALEEB, GEORGE; MCGEE, TOM; TWIGG, LARRY; SUMNICHT, GRANT; HENDRICK, FRANCOIS; MERLAUD, ALEXIS; FAYT, CAROLINE; HERMANS, CHRISTIAN; PINARDI, GAIA; DORNER, STEFFEN; WAGNER, THOMAS; LAUSTER, BIANCA; UBELE, ALMA; MENDES, ALEX ; LOPES, FABIO ; LANDULFO, EDUARDO ; SPINEI, ELENA; QUEREL, RICHARD; KARAGKIOZIDIS, DIMITRIS; BAIS, ALKIS; HUTJES, RONALD. Overview of the 2019 Sentinel-5p TROpomi vaLIdation eXperiment (TROLIX). In: EGU GENERAL ASSEMBLY, May 4-8, 2020, Online. Abstract... Göttingen, Germany: Copernicus, 2020.

    Abstract: For the validation of Sentinel-5p/TROPOMI the TROpomi vaLIdation eXperiment (TROLIX) was held in the Netherlands based at the Cabauw Experimental Site for Atmospheric Research during September 2019. TROLIX consisted of active and passive remote sensing platforms in conjunction with several balloon-borne and surface measurements. The intensive observations will serve to establish the quality of TROPOMI L2 main data products (UVAI, Aerosol Layer Height, NO2, O3, HCHO, Clouds) under realistic conditions with varying cloud cover and a wide range of atmospheric conditions. Since TROPOMI is a hyperspectral imager with a very high spatial resolution of 3.6 x 5.6 km2, understanding local effects such as inhomogeneous sources of pollution, sub-pixel clouds and variations in ground albedo is important to interpret TROPOMI results. Therefore, the campaign included sub-pixel resolution local networks of sensors, involving MAXDOAS and Pandora instruments, around Cabauw (rural) and within the city of Rotterdam (urban). Utilising its comprehensive in-situ and remote sensing observation program in and around the 213 m meteorological tower, Cabauw was the main site of the campaign with focus on vertical profiling using lidar instruments for aerosols, clouds, water vapor, tropospheric and stratospheric ozone, as well as balloon-borne sensors for NO2 and ozone. The data set collected can be directly compared to the TROPOMI L2 data products, while measurements of parameters related to a-priori data and auxiliary parameters that infuence the quality of the L2 products such as aerosol and cloud profiles and in-situ aerosol and atmospheric chemistry were also collected.

    Palavras-Chave: satellites; orbits; ozone; monitoring; atmospheric chemistry

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  • IPEN-DOC 27961

    GATTI, LUCIANA V. ; DOMINGUES, LUCAS G. ; BASSO, LUANA S. ; MILLER, JOHN B.; CASSOL, HENRIQUE L.G.; MARANI, LUCIANO; CORREIA, CAIO S. de C. ; TEJADA, GRACIELA; ARAGAO, LUIZ E.O.C.; ANDERSON, LIANA O.; GLOOR, MANUEL; PETERS, WOUTER; VON RANDOW, CELSO; NEVES, RAIANE A.L.; IPIA, ALBER; CRISPIM, STEPHANE P.; ARAI, EGIDIO. Sensitivity of Amazon Carbon Balance to climate and human-driven changes in Amazon. In: AGU CHARPMAN CONFERENCE, August 26-29, 2019, San Diego, CA, USA. Abstract... Washington, DC, USA: American Geophysical Union, 2019.

    Abstract: Amazon is the major tropical land region, with critical processes, such as the carbon cycle, not yet fully understood. Only very few long-term greenhouse gas measurements is available in the tropics. The Amazon accounts for 50% of Earth’s tropical rainforests hosting the largest carbon pool in vegetation and soils (~200 PgC). The net carbon exchange between tropical land and the atmosphere is critically important because the stability of carbon in forests and soils can be disrupted in short time-scales. The main processes releasing C to the atmosphere are deforestation, fires and changes in growing conditions due to increased temperatures and droughts. Such changes may thus cause feedbacks on global climate. In the last 40 years, Amazon mean temperature increased by 1.1ºC. The length of the dry season is also increasing. We observed a reduction of 50.5mm in the annual mean precipitation during this same 40 years period. Precipitation reduction occurred mainly in the dry season, exacerbating vegetation water stress with consequences for the carbon balance. To understand the consequences of climate and human-driven changes on the C budget of Amazonia, we put in place the first program with regional representativeness, from 2010 onwards, aiming to quantify greenhouse gases based on extensive collection of vertical profiles of CO2 and CO. Regular vertical profiles from the ground up to 4.5 km height were performed at four sites along the main air-stream over the Amazon. Here we will report what these new data tell us about the greenhouse gas balance and its controls during the 2010-2017. Along this period we performed 513 vertical profiles over four strategic regions that represent fluxes over the entire Amazon region. The observed variability of carbon fluxes during these 8 years is correlated with climate variability (Temperature, precipitation, GRACE) and human-driven changes (Biomass Burning). The correlations were performed inside each influenced area for each studied site. It was observed a persistent C source from the Amazon (natural plus anthropogenic sources) to the atmosphere. Amazon was a consistent source of 0.4 ± 0.2 PgC/year on average considering the Amazon area of 7.2 million km2. Fire emission is the main source of carbon to the atmosphere, which is not compensate by the C removal from old-growth Amazon forest.

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  • IPEN-DOC 27960

    TEJADA, GRACIELA; GATTI, LUCIANA V. ; BASSO, LUANA S.; MARANI, LUCIANO; CASSOL, HENRIQUE L.G.; CRISPIM, STEPHANE P.; NEVES, RAIANE A.L.; DOMINGUES, LUCAS G. ; IPIA, ALBER; CORREIA, CAIO S. de C. ; ARAI, EGIDIO; GLOOR, EMANUEL U.; MILLER, JOHN B.; VON RANDOW, CELSO. Land use and cover change and CO2 atmospheric measurements in the Amazon forests. In: AGU CHARPMAN CONFERENCE, August 26-29, 2019, San Diego, CA, USA. Abstract... Washington, DC, USA: American Geophysical Union, 2019.

    Abstract: In the last years, global CO2 concentrations have reach levels never seen before reaching more than 400 ppm. Among the main causes of these emissions are the burning of fossil fuels and the land use and cover change (LUCC) related emissions. In the Amazon region, the main CO2 emissions are related to deforestation. Multitemporal LUCC datasets have been restrict to Brazil, but now has been released a pan-Amazon dataset for all the countries sharing the Amazon, opening the possibility of studying the Amazon forests as a whole. On the other hand, the lower-troposphere greenhouse gas (GHG) monitoring program “Carbam project”, has been collecting biweekly GHGs vertical profiles in four sites of the Amazon since 2010, filling a very important gap in regional GHGs measurements. Our purpose is to understand the relationships between regional LUCC and CO2 aircraft measurements in the Amazon. Here we present the relationships between annual LUCC data from 2010 to 2017 in the Amazon forest and in each mean influence area of Carbam sites comparing them with mean annual CO2 fluxes. Considering the whole Amazon forests and the mean annual CO2 fluxes, the years with more forest loss and agriculture increase are 2010 and 2016, showing relation with CO2 fluxes. On the other hand, 2011 and 2017 also have deforestation (less than 2010 and 2016), but the CO2 fluxes are lower, showing that droughts could also influence the CO2 concentrations. Looking at each influence area, total carbon flux of Alta Floresta and Rio Branco have the same tendency as the forest loss from 2013 to 2017, but no in 2010 and 2012. In Tabantinga, Tefé and Santarem there is no a direct relationship between the carbon fluxes and the forest loss. To understand better the relationships at each site, we have to consider the years of measurements. Also, the temporal scale, carbon fluxes are measure biweekly and the LUCC data is annual. Looking at the potentialities and limitations of this relationship, it will be possible to improve the methodology to better understand the interaction of human activities and CO2 emissions on the carbon balance.

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  • IPEN-DOC 27959

    CASSOL, HENRIQUE L.G.; DOMINGUES, LUCAS G. ; BASSO, LUANA S. ; GATTI, LUCIANA V. ; MARANI, LUCIANO; TEJADA, GRACIELA; CRISPIM, STEPHANE P.; NEVES, RAIANE A.L.; CORREIA, CAIO S. de C. ; ARAI, EGIDIO; GLOOR, MANUEL; MILLER, JOHN B.; ANDERSON, LIANA O.; ARAGAO, LUIZ E.O.C.. Increasing of carbon emission from biomass burning due to the temperature rising and precipitation reduction in the Amazon. In: AGU CHARPMAN CONFERENCE, August 26-29, 2019, San Diego, CA, USA. Abstract... Washington, DC, USA: American Geophysical Union, 2019.

    Abstract: Recent droughts have increased the magnitude and frequency of the forest fires in the Amazon (Aragão et al. 2018). As a consequence, the Amazon has become a Carbon source due to the rising of the Carbon emission from biomass burned in the El Niño events. Faced with climate change and the likely acceleration of temperature in tropical regions, we hypothesize that Amazon will become a Carbon source even in non-droughts years, due to the increase of forest fires. Therefore, we compared 7 years of atmospheric profiles of CO2 obtained from aircraft overfly at four sites of the Amazon, since 2010, with temperature, precipitation, and fire counts (FC). Carbon emission from fires was obtained by the ratio of CO/CO2 and differs by site and year. The FC and climatic variables were extracted from quarterly influence areas by site and weighted by the amount of trajectories within a cell of one degree resolution. The fire emissions released by the Amazon is about 0.38 ± 0.086 Pg.C.yr-1, which represent roughly 17% of the annual global fires emissions (Werf et al. 2017). However, there are markedly divergences in the Fire emissions across Amazon. For instance, the emission from the Eastern is 400% higher and account of an average 60% more FC than observed in the Western. FC were positively and significantly correlated with Carbon from fires at all sites (ρ = 0.55-0.83, α = 0.05, p-value<0.001), being higher in the Southeastern of Amazon (Alta Floresta and Santarém sites), and lower in the Northwest of Amazon (Tefé site and Rio Branco Sites). This discrepancy may occur due to the Southeastern of Amazon be located inside the “Arc of deforestation” where the dynamic of the Land-Use Land-Cover Change is more pronounced. We also found a strong relationship between FC and temperature and precipitation (r² adj = 0.44-0.67, p-value<0.001). Temperature is positively correlated with FC and explains circa of 90% of their variability in the linear model (r² partial = 0.4-0.59, α = 0.05, p-value<0.001). It means that an increase of one degree (1°C) in the Amazon represents an increase of about 13600 fire counts; and the reduction of 100 mm precipitation means an increase of 315 in the fire counts. In the balance of the Fire emissions, it would add 1.27 Pg Pg.C.yr-1 at each degree celsius of increase and 0.2 Pg.C.yr-1 at each 100 mm of precipitation reduction.

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  • IPEN-DOC 27958

    BASSO, LUANA S.; GATTI, LUCIANA V. ; MARANI, LUCIANO; CASSOL, HENRIQUE L.G.; TEJADA, GRACIELA; DOMINGUES, LUCAS G. ; CORREIA, CAIO S. de C. ; IPIA, ALBER; ARAI, EGIDIO; ARAGAO, LUIZ E.O.C.; ANDERSON, LIANA O.; CRISPIM, STEPHANE P.; NEVES, RAIANE A.L.; GLOOR, MANUEL; MILLER, JOHN B.. Understanding the seasonality and interannual variability of Amazon CH4 budget and climate feedbacks based on atmospheric data from vertical profiles measurements. In: AGU CHARPMAN CONFERENCE, August 26-29, 2019, San Diego, CA, USA. Abstract... Washington, DC, USA: American Geophysical Union, 2019.

    Abstract: Currently tropical land regions, like Amazon, are still poorly observed with large-scale integrating in-situ observations although they host some of the largest wetlands/seasonally flooded areas on the globe. The role of these regions in the global CH4 balance and the climate feedbacks have remained uncertain. To help this situation we have started a lower-troposphere greenhouse gas-monitoring program over tropical South America consisting of regular vertical profile greenhouse gas and carbon monoxide (CO) observations at four sites along the main airstream since 2010. Vertical profiles are sampled using light aircraft, high-precision greenhouse gas and carbon monoxide analysis of flask air, fortnightly between 2010 to 2017. Over the full period the Amazon (total area of around 7.2 million km2) was a source of CH4, of approximately 46 ± 6 Tg/year, which represent 8% of the global CH4 flux to the atmosphere. CH4 emissions from different parts of the basin vary markedly. There are comparably high emissions from the eastern part of the basin exhibiting strong variability, with particularly high CH4 fluxes in the early part of the wet season (January to March). A second period of high emissions occurs during the dry season. The cause of the high emissions is unclear. In contrast to the eastern Amazon site a clear seasonality was observed at the other three sites located further downwind along the main sir-stream, with the largest emissions occurring at the beginning of the wet season (January to March). In addition, these data show an interannual variability in emissions magnitude, so we discuss how these data can be correlate to temperature, precipitation, terrestrial water storage anomalies (from GRACE) and Fire counts (human-driven changes) that could be influencing this variability. Using a CO/CH4 emission ratio calculated in this study we find a biomass burning contribution varying between 10 and 23% of the total flux at each site. Also, we discuss what the data tell us about possible ongoing feedbacks to possible changes in temperature, precipitation and biomass burning and indicating what variables can be contributing to CH4 emissions from Amazon.

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  • IPEN-DOC 27957

    KORKISCHKO, IVAN ; MAFFEI, FELIPE S.; GIORIA, RAFAEL dos S.; MENEGHINI, JULIO R.. Geometric parameter optimization of a liquid jet liquid ejector. In: ANNUAL MEETING OF THE APS DIVISION OF FLUID DYNAMICS, 72nd, November 23-26, 2019, Seattle, Washington, USA. Abstract... Maryland, USA: American Physical Society, 2019.

    Abstract: Ejectors are devices employed as pumps or compressors, which work transferring momentum from a primary fluid (high pressure) to a secondary fluid (low pressure). On the one hand, their main advantages over standard pumps and compressors are no moving parts, no need of lubricants and seals, and low noise and maintenance. On the other hand, ejectors have low efficiency compared to other devices and a very narrow region of optimal operation. Thus, ejectors certainly benefit from optimization studies. This investigation was based on a CFD model of a liquid jet liquid (LJL) ejector. The finite element method was used, coupled with the k-epsilon turbulence model. The optimization study had three steps. First, the constants of the turbulence model were recalibrated to minimize the difference between the numerical and experimental efficiency curves. Second, using the main geometric parameters as control variables, the peak efficiency was maximized. Finally, the optimized geometry was further improved, considering the transitions between the different ejector components, which were originally sharp corners. The optimized round corners increased the ejector efficiency.

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  • IPEN-DOC 27952

    MOREIRA, EDSON G. ; SILVA, PAULO S.C. ; MAIHARA, VERA A. ; TAPPIZ, BRUNO ; NISTI, MARCELO B. ; SAUEIA, CATIA H.R. ; CARVALHO, RICARDO N. . Naturally occurring radionuclides in a fish reference material. In: INTERNATIONAL SYMPOSIUM ON NATURALLY OCCURRING RADIOACTIVE MATERIAL, 9th, September 23-27, 2019, Denver, Colorado, USA. Apresentação... 2019.

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  • IPEN-DOC 27949

    AMARAL, MARCELLO M.; DEL-VALLE, MATHEUS ; RAELE, MARCUS P. ; PRETTO, LUCAS R. de . Laser speckle imaging for osteoporosis evaluation. In: ENCONTRO DE OUTONO DA SOCIEDADE BRASILEIRA DE FÍSICA, 43., 23-26 de novembro, 2020, Online. Resumo... São Paulo, SP: Sociedade Brasileira de Física, 2020.

    Abstract: Osteoporosis is a common disease characterized by the reduction on Bone Mineral Density (BMD), leading to weakening of bone structure, Chronic pain, deformities and loss of quality of life. In addition to the clinical evaluation, dual-energy X-ray absorptiometry is one of the main techniques to diagnose it. However, this technique uses ionizing radiation to assess the bone structure and therefore cannot be used very often by patients, due to radiological safety reasons. On the other hand, optical techniques are known for its safe use, due to non-ionizing radiation, however, optical techniques do not easily allows the analysis of bone tissue. This limitation could be circumvented in the oral cavity area. In this work we used the Laser Speckle Imaging (LSI) technique to evaluate maxilla and mandible bones after demineralization prosses in an animal in vitro model. Osteoporosis lesions were simulated in sixteen mandible and twelve maxilla slabs using Ethylenediaminetetraacetic Acid (EDTA) 0.5 M for 0 (control) 7, 15 and 30 days. The roughness parameters Ra and Rq were analyzed with optical profilometry (ZeGage, Zygo, USA) to characterize the demineralization process. The LSI images were measured by custom experimental setup. A collimated laser beam at 635 nm and 1.3mW (Thorlabs CPS635R), expanded by a diverging lens (-75 mm), illuminates the sample. The scattered signal was imaged by a CCD camera (Thorlabs - DCC1645-HQ), an adapter (Thorlabs MVLCMC) and objective lens (Thorlabs/Navitar - MVL12X3Z) setting. A custom software was implemented to measure the speckle patches ratio and the speckle contrast ratio from speckle images obtained by a custom LSI setup. The speckle contrast ratio method only differentiate sound from osteoporotic tissue. The speckle patches ratio method presented a negative correlation with the roughness parameter, and consequently with the demineralization level. It was concluded that LSI is a promissory technique for assessment osteoporosis lesions on alveolar bone and, for that, the patches ratio is the best methodology for detecting and differentiating several degrees of demineralization.

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  • IPEN-DOC 27948

    VALENCA, J.V.B.; ANTONIO, P.L. ; CALDAS, L.V.E. ; SILVA, A.C.A.; DANTAS, N.O.; D'ERRICO, F.; SILVEIRA, I.S.; SOUZA, S.O.. Optically stimulated luminescence of different borate glass compositions. In: ENCONTRO DE OUTONO DA SOCIEDADE BRASILEIRA DE FÍSICA, 42., 26-31 de maio, 2019, Aracaju, SE. Resumo... São Paulo, SP: Sociedade Brasileira de Física, 2019.

    Abstract: Radiation detection applications are pointed out as one of the emerging research areas in glass science. Borate glass presents desirable characteristics for dosimetric applications. The main goal of this work was to analyze the optically stimulated luminescence (OSL) signal for different lithium borate glasses containing magnesia (LMB), quicklime (LCB) or potassium carbonate (LKB). Five different glass formulations were produced for each batch. All formulations were produced by using a melt-quenching method and analyzed in terms of both dose-response and OSL shape decay after submitted to beta irradiation. Pre-heating treatments were also used in the OSL analysis of the samples. The X-ray diffractometry (XRD) and differential thermal analysis (DTA) confirmed the glassy state of the produced samples. In our research, we observed that glass modified with potassium, LKB, is more sensitive to radiation compared with samples produced with magnesium and calcium. Regarding the study done with the LKB formulations, differences in the sensitivity ranking were observed as we either analyzed the OSL signal based on the integrated signal or the emission in the very first 0.16 s. A comparison of this difference was extended to all formulations in the LKB group, which showed that the parameter used to plot the dose-response curve has to be considered in the process of analyzing glassy materials, as it can influence in possible applications. Pre-heating studies also showed tendencies for the studied compositions that were already discussed in the specialized literature for phosphate glass.

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  • IPEN-DOC 27947

    SILVA, ANDERSON M.B.; SOUZA, DIVANIZIA N.; JUNOT, DANILO O. ; CALDAS, LINDA V.E. . Thermoluminescent analysis of silver addition in CaSO4 : Tb. In: ENCONTRO DE OUTONO DA SOCIEDADE BRASILEIRA DE FÍSICA, 42., 26-31 de maio, 2019, Aracaju, SE. Resumo... São Paulo, SP: Sociedade Brasileira de Física, 2019.

    Abstract: According to results of the literature, some unusual rare earth elements, such as terbium, have been shown to be promising as a dopant in CaSO4 matrix. Silver has also been used in the co-dopant function. As there are no reports on the structural characterization of CaSO4 : Tb with the incorporation of silver, the aim of this work was to produce and characterize terbium doped CaSO4 crystals, co-doped with silver oxide (Ag (Ox)) and silver nanoparticles (Ag (NP)). The main purpose is to use them as alternative TL dosimeters to those commercially available. The phosphors were produced by the slow evaporation route and characterized by X-ray diffraction (XRD), which confirmed the viability of the route, and by scanning electron microscopy (SEM). The silver nanoparticles were produced by the method of Lee and Meisel and characterized by ultraviolet-visible spectrophotometry (UV-Vis), SEM and XRD. The composites in the form of pellets were obtained from the addition of Teflon to the phosphors. The TL emissions of the new materials produced were investigated. It was observed that the addition of silver as a co-dopant in the CaSO4 : Tb matrix shifts its main TL peak to higher temperatures, and the presence of Ag (NP) increases the intensity of this peak. By means of the TL emission curves of the composites, some parameters associated with the charge transfer processes in these materials were determined. The lower detection limit of the composites was also evaluated. The crystals of CaSO4 : Tb; Ag(NP) presented higher sensitivity than CaSO4 : Tb; Ag(Ox). All samples have a luminescent signal reproducible and linear, with TL responses proportional to the absorbed doses.

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  • IPEN-DOC 27946

    POLO, IVON O. ; CALDAS, LINDA V.E. ; SANTOS, WILLIAM S. . Monte Carlo approach for the determination of the angular dependence of an extrapolation chamber response. In: ENCONTRO DE OUTONO DA SOCIEDADE BRASILEIRA DE FÍSICA, 42., 26-31 de maio, 2019, Aracaju, SE. Resumo... São Paulo, SP: Sociedade Brasileira de Física, 2019.

    Abstract: The angular dependence of an extrapolation chamber response is reported. The determination of the angular factors were carried out using the MCNP Monte Carlo Method. To determine the angular dependence, the PTW type 23392 extrapolation chamber of the Laboratory for Calibration of Instruments (LCI/IPEN) was simulated. The experiments were performed for the radiation fields of beta secondary standard BSS2 system sources. For the 90Sr/90Y source, the calibration distance of 11 cm without the beam flattening filter was used. For the 85Kr and 147Pm sources, the distances of 30 cm and 20 cm with the filter were used, respectively. The simulations were carried out by rotating the extrapolation chamber around the reference axis for angles between -90º and 90º, in steps of 5º. For the 90Sr/90Y source the angular dependence factor is greater than 1, predominating the dose build-up effect up to 60º and -60º, and the factor is less than 1 for the other angles, prevailing the absorption of beta particles. For the 85Kr and 147Pm sources, the angular dependence factor is less than 1 for all angles, predominating the absorption of beta particles too. The determined angular factors are in good agreement with the international report ISO 6980.

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  • IPEN-DOC 27937

    PARRA, V.; PARRA, D.F. ; SANTOS, V. . Comparação da liberação de neomicina entre um hidrogel e um argilogel. In: WORKSHOP DE BIOMATERIAIS, ENGENHARIA DE TECIDOS E ORGÃOS ARTIFICIAIS, 6th, October 29-31, 2019, São Paulo, SP. Abstract... São Paulo, SP, 2019. p. 360-360.

    Abstract: Os hidrogéis poliméricos são sistemas naturais ou sintéticos, que ganharam interesse devido à sua alta biocompatibilidade com tecidos moles. Estes tipos de hidrogéis têm sido utilizados para curativos como um sistema de entrega de medicamentos. No presente estudo os sistemas de cicatrização de feridas baseadas em hidrogéis poliméricos foram preparados usando poli (N-vinil-2-pirrolidona) (PVP), poli (etilenoglicol) (PEG), ágar e neomicina droga seguida de irradiação gama para promover reticulação e esterilização. A influência do processo de irradiação com dose de 25 kGy foi investigada. A fração gel e intumescimento máximo foram estimados usando métodos físico-químicos e constatou-se a ocorrência de cerca de 95% de fração de gel, relativa a polímero reticulado; e intumescimento de 1100% após 8 horas de imersão. A neomicina liberada do hidrogel foi avaliada por cromatografia líquida com identificação por Espectrometria de Massa. Trabalhos realizados no IPEN atestaram que a neomicina foi liberada em cerca de 8h e a concentração da droga permaneceu constante por 48 h. Já no caso de argilogéis a liberação é mais lenta em razão da presença da argila e depende da concentração da mesma. O hidrogel / neomicina exibiu efeitos antibacterianos contra o Staphylococcus aureus. Com estes resultados, pode-se inferir que o sistema hidrogel / neomicina é um candidato potencial para compor curativos de feridas.

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  • IPEN-DOC 27938

    OLIVEIRA, A.P.; RODAS, A.C.D.; DERNOWSEK, J.A.; QUEIROZ, A.; SANTOS, F.A. ; RICCARDI, C.S.. Formulações de biotintas à base de alginato contendo suspensão de células e esferóides, considerando parâmetros otimizados no fatiamento. In: WORKSHOP DE BIOMATERIAIS, ENGENHARIA DE TECIDOS E ORGÃOS ARTIFICIAIS, 6th, October 29-31, 2019, São Paulo, SP. Abstract... São Paulo, SP, 2019. p. 424-424.

    Abstract: A biotecnologia está ligada a várias ciências, porém, nos últimos anos, devido ao aumento da expectativa de vida da população, diversas abordagens foram destacadas como alternativa para minimizar os problemas decorrentes da idade. Nesse contexto, a engenharia de tecidos emerge uma ciência que visa projetar e ou sintetizar tecidos biocompatíveis capazes de favorecer a regeneração, melhorando aspectos da qualidade de vida da população. Uma das ferramentas mais usadas na engenharia de tecidos é a bioimpressão 3D, que envolve vários parâmetros: modelagem 3D, estruturação, maturação e análise. Vale ressaltar que o bioink consiste em formulações de célula esférica (esferóide) / agregado celular, que também podem conter moléculas ativas e biomateriais. No presente trabalho, foi realizado uma comparação entre diferentes biotintas à base de alginato, considerando uma formulação contendo suspensão celular e outra esferóides. Utilizaram-se fibroblastos de camundongo da cepa 3T3. No entanto, para a produção de esferóides, foi utilizada a técnica de Hidrogéis não Adesivo micromoldados, considerando o hidrogel de agarose. Os parâmetros utilizados no processo de bioimpressão foram otimizados usando o software Simplify 3D®. As análises dos construtos obtidos nas duas formulações dos biótipos foram realizadas por meio de Microscopia de Fluorescência, sendo possível analisar aspectos do diâmetro do filamento, dispersão celular e proliferação celular. Em relação ao diâmetro do filamento, a formulação contendo apenas a suspensão celular resultou em diâmetros mais uniformes. Em relação à dispersão celular, ambas as formulações apresentaram resultados satisfatórios, resultando em uma distribuição homogênea em todo o filamento e os resultados sobre a proliferação celular foram promissores. A bioimpressão não é um processo trivial e envolve vários parâmetros e processos; no entanto, foi possível obter resultados interessantes usando uma bioimpressora de baixo custo.

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  • IPEN-DOC 27943

    RODRIGUES, BRUNO L.; MAISTRO, CARLOS B.; FLOSI, ADRIANA A.; BERTOTTI, VICTOR A.; YORIYAZ, HELIO ; NUNES, MAIRA G. . Impacto dosimétrico de curvas CT-to-ED em irradiações de próteses e heterogeneidades de alto número atômico. In: CONGRESSO BRASILEIRO DE FÍSICA MÉDICA, 24., 21-24 de agosto, 2019, Santos, SP. Resumo expandido... São Paulo, SP: Associação Brasileira de Física Médica, 2019.

    Abstract: A presença de próteses em radioterapia normalmente está associada a limitações no planejamento e a imprecisão no cálculo de dose. Embora existam algoritmos precisos de correção de heterogeneidade, a principal dificuldade está no estabelecimento de curvas de correção CT-to-ED para altos valores de HU. A maioria dos tomógrafos trabalha em 12 bits, saturando em torno de 3070 HU, no entanto já existem equipamentos de 16 bits que não saturam na presença de materiais de alto número atômico (Z). O objetivo deste trabalho foi avaliar, em irradiações de heterogeneidades de alto Z, o ganho dosimétrico quando são utilizadas curvas de correção que incluem altos valores de HU. Os resultados indicaram uma dependência significativa das curvas com o tomógrafo avaliado, impactando diretamente na correção de heterogeneidades e causando desvios de até 11,3% em termos de atenuação.

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  • IPEN-DOC 27942

    MELETTI, AMANDA F.; BARSANELLI, CRISTIANE; RIBEIRO, VICTOR A.B.; YORIYAZ, HELIO ; SHORTO, JULIAN M.B. ; SIQUEIRA, PAULO T.D. ; NUNES, MAIRA G. . Levantamento da curva CT-TO-ED para CBCT. In: CONGRESSO BRASILEIRO DE FÍSICA MÉDICA, 24., 21-24 de agosto, 2019, Santos, SP. Resumo expandido... São Paulo, SP: Associação Brasileira de Física Médica, 2019.

    Abstract: A fim de se aproveitar a Tomografia de Feixe Cônico (CBCT) utilizada em técnicas de IGRT para estimar a dose entregue aos pacientes, foi levantada a curva CT-to-ED do sistema kV-CBCT da Elekta-XVI por meio do CatPhan® – objeto simulador com densidades conhecidas. Foram verificadas diferenças de até 36,7% nos valores de HUs obtidos com diferentes parâmetros de aquisição da CBCT, tornando-se essencial o estabelecimento de protocolos específicos de imageamento em cada Instituição. Apesar de o método até aqui empregado ter sido validado com desvios percentuais menores que 0,23%, diferenças ainda maiores foram verificadas entre as curvas da CT de referência e as da CBCT, o que torna indispensável estudar estratégias de correção que viabilizem a sua implementação na clínica.

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  • IPEN-DOC 27936

    SANTOS, F.A. ; OLIVEIRA, A.P.; QUEIROZ, A.; RODAS, A.C.D.; SILVA, J.V.L.; DERNOWSEK, J.A.. Optimization of alginate/pluronic-based hydrogel slicing parameters for complex structure in bioprinting. In: WORKSHOP DE BIOMATERIAIS, ENGENHARIA DE TECIDOS E ORGÃOS ARTIFICIAIS, 6th, October 29-31, 2019, São Paulo, SP. Abstract... São Paulo, SP, 2019. p. 340-340.

    Abstract: A bioimpressão 3D está em constante crescimento e inserida na biofabricação onde envolve vários parâmetros e processos. Uma das propriedades que precisamos é uma boa estruturação do construto bioimpresso. No entanto, a reologia dos hidrogéis compostos por biomateriais é um fator determinante para a construção estável das geometrias impressas. Estratégias de estruturação física (temperatura, luz, rigidez, tensão) e química (pH, adição de moléculas indutoras) podem ser utilizadas. Nesse trabalho utilizamos um hidrogel a base de Alginato e Pluronic127 onde houve uma estruturação envolvendo fenômenos químico com cloreto de cálcio e térmico durante o processo. Inicialmente foi realizado a formulação do hidrogel - alginato 8% e Pluronic 25% - e em seguida a parametrização do fatiamento da geometria, realizada no software Simplify3D. Após a fase de fatiamento da geometria 3D realizamos a impressão do modelo de nariz retirado do banco de dados Thingiverse, disponível no site thingiverse.com.O trabalho ainda está em andamento, mas já alcançamos resultados satisfatórios. No entanto, para alcançar uma formulação mais próxima do ideal, serão necessários mais estudos.

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  • IPEN-DOC 27749

    SILVA, FABIO F.A. da ; SANTOS, SOFIA N. dos ; PIJEIRA, MARTHA S.O. ; BERNARDES, EMERSON S. . Radiochemistry and pharmacokinetics of Pectin (MCP): a molecule with theranostics potential. In: CONGRESSO BRASILEIRO DE MEDICINA NUCLEAR, 34., 4-7 de setembro, 2020, Online. Resumo expandido... São Paulo, SP: Sociedade Brasileira de Medicina Nuclear, 2020.

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  • IPEN-DOC 27748

    SILVA, JOSE L. da ; MARTINS, PATRICIA de A. ; SANTOS, JOEL M. dos; SILVA, LAERCIO da ; SILVA, NATANAEL G. da ; FUKUMORI, NEUZA T.O. ; MATSUDA, MARGARETH M.N. . Determinação de estanho total por ICP-OES em reagentes liofilizados. In: CONGRESSO BRASILEIRO DE MEDICINA NUCLEAR, 34., 4-7 de setembro, 2020, Online. Resumo expandido... São Paulo, SP: Sociedade Brasileira de Medicina Nuclear, 2020.

    Abstract: O tecnécio-99m (99mTc) é o radioisótopo mais utilizado na medicina nuclear para obtenção de imagens para diagnóstico por SPECT. Seu estado de oxidação pode variar de -1 a +7, quando reage com uma variedade de compostos na presença de Sn(II).O cloreto estanoso diidratado é o agente redutor do 99mTc mais utilizado na formulação de reagentes liofilizados(RL). A determinação quantitativa de estanho total e Sn(II) são controles importantes para o processo de fabricação a fim de garantir a qualidade durante o prazo de validade dos RL. O objetivo deste trabalho foi quantificar o Sn total nos RL MDP-TEC e MIBI-TEC (IPEN) usando ICP-OES como método alternativo ao método colorimétrico descrito nas farmacopeias. As massas quantificadas de cloreto estanoso nos RL analisados estiveram compreendidas entre 90-110 % em relação ao descrito na bula do radiofármaco. O método analítico proposto por ICP-OES mostrou-se excelente para determinação de Sn total.

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  • IPEN-DOC 27747

    MARTINS, PATRICIA de A. ; SANTOS, JOEL M. dos; SILVA, JOSE L. da ; SILVA, LAERCIO da ; FUKUMORI, NEUZA T.O. ; ARAUJO, ELAINE B. de ; HIROMOTO, GORO ; MATSUDA, MARGARETH M.N. . Controle radionuclídico de radiofármacos de Lu-177. In: CONGRESSO BRASILEIRO DE MEDICINA NUCLEAR, 34., 4-7 de setembro, 2020, Online. Resumo expandido... São Paulo, SP: Sociedade Brasileira de Medicina Nuclear, 2020.

    Abstract: O lutécio-177 (Lu-177) é um radioisótopo produzido em reator, com meia-vida física (t/) de 6,73 dias e decaimento por emissão beta de 498,3 keV e raios y energias de 208,37 keV e 112,9 keV, adequados para o tratamento de câncer de tumores neuroendócrinos e de próstata. A determinação da pureza radionuclídica de radiofármacos de lutécio-177 visa verificar se a porcentagem de radionuclídeos atendem aos critérios estabelecidos na Farmacopeia Europeia (FE). Este trabalho tem por objetivo estabelecer as condições para realizar o controle radionuclídico de DOT-IPEN-177 produzido no IPEN-CNEN/ SP. Os resultados de identificação e pureza radionuclídica de DOT-IPEN-177 encontrados foram satisfatórios pois atenderam aos critérios estabelecidos na FE.

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  • IPEN-DOC 27746

    BALIEIRO, LUIZA M. ; BELLINI, MARIA H. ; ARAUJO, ELAINE B. de . Avaliação da biodistribuição do radiofármaco Fluorestradiol-18F em animais sadios e com modelo tumoral. In: CONGRESSO BRASILEIRO DE MEDICINA NUCLEAR, 34., 4-7 de setembro, 2020, Online. Resumo expandido... São Paulo, SP: Sociedade Brasileira de Medicina Nuclear, 2020.

    Abstract: O Fluorestradiol-18F (FES-18F) é um radiofármaco promissor para utilização, por método não-invasivo de tomografia de emissão de pósitrons (PET) no diagnóstico de câncer de mama ER+. Estudos pré-clínicos em animais sadios e com modelo tumoral desenvolvido com células MCF-7 apresentaram captação do FES-18F nos órgãos com receptores de estrogênio, tumor e significativa captação no fígado e intestinos, com perfil metabólico semelhante ao estradiol.

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  • IPEN-DOC 27694

    DOMINGUES, LUCAS; GATTI, LUCIANA ; AQUINO, AFONSO ; CORREIA, CAIO ; SANCHES, ALBER; GLOOR, EMANUEL; MILLER, JOHN; PETERS, WOUTER; TURNBULL, JOCELYN; BASSO, LUANA; TEJADA, GRACIELA; CASSOL, HENRIQUE; MARANI, LUCIANO. CO measurements as a biomass burning carbon emission tracer at the Amazon Basin. In: VIRTUAL GLOBAL MONITORING ANNUAL CONFERENCE, June 12 - August 7, 2020, Online. Resumo expandido... 2020.

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  • IPEN-DOC 27677

    FREITAS, L.F. ; CRUZ, C.C. da ; BATISTA, J.G. ; VARCA, G.H. ; LUGAO, A.B. ; MATHOR, M.B. . Hybrid gold-protein nanoparticles as radiosensitizers. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Gold nanoparticles present unique optical properties which are dependent upon size and morphology, and consist on a differential interaction with radiation compared to the bulk material. Those nanoparticles can be modified in order to adjust their bioavailability and tissue-targeting, and one of the means to do so is by adsorbing one or more types of proteins onto their surface. Gamma radiation can be helpful in this regard, since it promotes intra- and intermolecular crosslinks in proteins and enables their adsorption onto the metallic nanoparticles’ surfaces. Here we present the results obtained for hybrid gold-protein nanoparticles as radiosensitizers. The nanoparticles were synthesized radiolytically by mixing 5 mmol L-1 NaAuCl4 with 1 mg mL-1 bovine serum albumin (BSA) or papain in the presence of 0.1 mol L-1 tert-butanol and 20% ethanol. The solutions were irradiated with 10 kGy in a multipurpose gamma irradiator (60Co source, 5 kGy per hour) for the radiolytic synthesis of the nanoparticles, and then the resulting red suspension was stored until use. 10^4 cells (MDA-MB-231 line) were seeded in 96-well plates and incubated with a 2:1 mixture of DMEM medium and nanoparticles suspension for 12 hours. Then, the wells were washed with sterile phosphate buffered saline, and fresh DMEM medium was added prior to irradiation in a gamma cell (60Co source, 0.6 kGy per hour) with 10, 30 and 50 Gy. 48 hours later, the cell viability was assessed by MTS assay. The results indicate that the radiation alone slightly stimulated the proliferation of the tumor cells, but this effect was more evident in the presence of gold-papain nanoparticles. The ablative effect due to radiosensitization was observed with 30 and 50 Gy for the cells incubated with gold-BSA nanoparticles, and 10 and 30 Gy for the cells incubated with gold-papain nanoparticles. This difference might be due to a more effective internalization or surface-attachment of nanoparticles when they are coated with papain, and one evidence for this assumption is the fact that the cell culture becomes red after the incubation with gold-papain nanoparticles. Therefore, protein-coated nanoparticles might be effective as radiosensitizers, depending on the coating and dose of radiation.

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  • IPEN-DOC 27676

    RIBEIRO, M.S. ; YOSHIMURA, T.M. ; TOLEDO, V.H.; HADDAD, P.S.. A novel superparamagnetic nanoplatform assisted by light against nonlocal bacterial infections. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: The increasing resistance to antimicrobials worldwide requires new strategies to fight infectious diseases. Antimicrobial photodynamic therapy (APDT) emerges in this scenario as a promising approach. APDT is a light-based therapy combined to a photosensitizer drug and oxygen that kills microorganisms via oxidative stress. Due to its mechanism of action, i.e., generalized oxidation of all cell structures, bacterial resistance to APDT is very improbable. Currently, however, APDT is limited to local treatments. Thus, a platform to deliver the photosensitizer drug in internal organs is urgently necessary. Superparamagnetic iron oxide nanoparticles (SPIONs) can be easily directed to target sites using an external magnetic field, which made them excellent drug delivery systems. In addition, their large surface to volume ratio allows the functionalization of therapeutic molecules on their surface. In this work, we synthesized and characterized SPIONs covered by methylene blue (MB)-entrapped silica (SPIONs-silica-MB) and investigated their potential combined to APDT to kill Escherichia coli, the most common bacteria found in urinary tract infections. We synthesized SPIONs by the co-precipitation of iron (II) and (III) chlorides in the presence of a weak base and covered them with a double layer of silica leading to the hybrid material magnetite-silica-MB. SPIONS were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, and magnetic measurements. Kinetics of MB release and production of singlet oxygen from SPION-silica-MB were also obtained. The average crystallite size of magnetite was found to be 14 nm. Infrared spectra showed characteristic bands of iron-oxygen and others associated with silicate groups. At room temperature, the nanoplatform presented magnetic behavior due to the magnetite core. MB release increased exponentially until 18 h, when it reached a plateau. Singlet oxygen was spontaneously released from SPIONs-silica-MB. To verify the photodynamic activity of SPIONs-silica-MB on bacterial cells, 1x10^7 colony forming units of E. coli were suspended in SPIONs-silica-MB PBS solution (50 microM of MB) and were irradiated using a red LED (625 ± 20 nm) of 235 mW over an orbital shaker to prevent precipitation during 5, 10, 15 and 20 min at three different MB release times: 6, 12 and 22 h. Proper controls were established and showed no killing. In contrast, SPIONs-silica-MB-mediated APDT promoted bacteria inactivation depending on both the time of MB release and irradiation time. Our results show that bacteria are completely eradicated following 22 h of MB release and 20 min of irradiation. These findings motivate the use of SPIONs-silica-MB to mediate APDT against nonlocal infectious diseases.

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  • IPEN-DOC 27675

    ZEN, H.A. ; LUGAO, A.B. . Effect of molecular sieve incorporation into fluoroelastomer on the mechanical properties. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: The nanoparticle incorporation improves mechanical and thermal properties, and also improve gas barrier property in a polymeric matrix. This incorporation can be facilitated by elastomer solubility, which permits a homogeneous distribution of the nancoparticle. In this work molecular sieve with 3A was incorporated into fluoroelastomer matrix at 0.5, 1, 2 and 5% weight. In a Banbury equipment was carried the nanoparticle and fluoroelastomer, in order to obtain nanocomposites. After that was performed the vulcanization process to obtain films with 0.5mm of thickness. The films were characterized by mechanical tests and swelling degree to determine the modification on mechanical properties of the fluoroelastomer matrix. The results showed an increase in the stiffness and in the tension at break values although the swelling values didn’t suffer drastic changes.

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  • IPEN-DOC 27674

    MELLO-CASTANHO, S. ; PARRA SILVA, J. ; YAMAGATA, C. . Surface activation of Palygoskite nanotubes for wastewater treatment. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: The ion exchange / sorption method is one of the most popular and attractive methods used to treat effluents containing heavy metals. The peculiar chemical characteristics, associated to the nanoscale of the structural network with the presence of natural nanotubes, as is the case of paligorsquita, makes it a potential candidate to meet the requirements of high sensitivity and selectivity in the extraction of heavy ions in wastewater. In the process of developing materials with sorption properties for the incorporation and subsequent immobilization of heavy ions in the same matrix, the most important steps are the generation of active sites, together with increased specific surface area. The parameters and conditions for the activation process of the natural Palygorskite nanotubes aiming to the sorption and immobilization of nickel ions present in wastewater from industrial activities were determined. Paligoskite from Piaui State Brazil, was used as raw material. The characterized and the acid activation process were selected for this development. Subsequent heat treatments were carefully selected conditions by thermal analysis (ATD/TG) to avoid collapse of the nanotubes. The results obtained of maximum sorption capacity for nickel on activated natural nanotubes were very promising. Structural folding observed in the clay may surely important contribution for the heavy metal immobilization processes. Finally, the optimization of the acid activation process is fundamental to improve the sorption’s capacities in solid-liquid medium for extraction specifics metals by activated natural nanotubes.

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  • IPEN-DOC 27673

    KLUMPP, R.E. ; VIVEIROS, B.G. ; SILVA, R.M. ; MAGNANI, M.; ANTUNES, R.A.; COSTA, I. . Corrosion protection for Aluminum surfaces of use in the aircraft industry by hybrid Sol-Gel/Cerium nanocomposite coating. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Localized corrosion is a threat for aluminum alloys structures used in the aircraft industry. Toxic and carcinogenic surface pre-treatments based on hexavalent chromium have been widely used due to its highly effective corrosion protection properties. However, since it has been increasingly banished from use, there is great interest in the development of surface pre-treatments by clean technology to replace those that generate toxic residues. In this work, a novel eco-friendly surface treatment based on an hybrid sol-gel/Cerium nanocomposite coating was proposed with the great advantage over other treatments proposed carried out in literature that consists in one single step process. The effect of this newly developed treatment on the morphology, chemical composition and corrosion resistance of an Alclad alloy (AA1230) surface used in the aeronautic sector was evaluated. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) analyzed surface morphology, whereas corrosion resistance was studied by electrochemical techniques and Neutral Salt-Spray Test (NSST). Chemical composition of the surface after treatment was analysed by X-ray photon electron spectroscopy (XPS). The results showed high corrosion resistance of the treated surface comparable to that provided by chromated surfaces. Besides, high adhesion of the treated surface to a varnish, indicated that it is a viable alternative for replacement of chromate layers obtained from solutions with hexavalent chromium ions. Advantages of the treatment are environmentally friendly, effective corrosion protection and low costs.

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  • IPEN-DOC 27672

    CARDOSO, E.C. ; PARRA, D.F. ; SCAGLIUSI, S.R. ; KOMATSU, L.G. ; LUGAO, A.B. . Ionizing radiation compatibilization in bio-based blends from PBAT/PLA reinforced with bio-eggshell. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Plastics global annual production exceeds 300 million tons and 99% is originated from oil or fossil combustibles. The amount of plastics wastes utilized exceeds the amount into landfills, prejudicing effectively the environment. As an alternative, they are being slowly replaced by bioplastics, as PLA (poly-lactic acid) and PBAT (butylene adipate co-terephthalate). Food and dairy industries produce annually huge amounts of avian eggshells residues and their disposition presents a serious environmental risk. Bio-load from avian eggshells as polymers reinforcement is based in their higher benefits as resistance and rigidity besides being a friendly environmental material, degradable and renewable. PLA and PBAT are thermoplastics capable to be processed by conventional methods: nevertheless, due to their high interfacial tension, it is required the use of compatibilizers. In this work, additives and heat generally used as compatibilizers were replaced by e-beam radiation, at 150 kGy dose. PBAT/PLA blends were prepared at the weight ratio of 82 / 18 and 5.0 phr of PLA 150 kGy e-beam radiated, at 2.5, 5.0 and 10.0 phr of bio-eggshells. Samples were homogeneized in a co-rotating twin-screw extruder and further characterized for: DSC, TGA, FTIR, XRD and Mechanical essays.

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  • IPEN-DOC 27671

    SCAGLIUSI, S.R. ; CARDOSO, E.C. ; LUGAO, A.B. . The degrading effects of the radiation on the properties of butyl rubber compounds. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Polymeric materials (plastics and rubber) have been contributing in a continuously and raising way for the generation of litter and industrial wastes discarded in landfills. Gamma ionizing radiation has capacity for changing structure and properties of polymeric materials and can be applied to almost all types of polymers; irradiation is an expectation for problem-solving of rubber wastes management that can be utilized as raw-materials or chemical additives. butyl rubber has excellent mechanical properties and oxidation resistance, as well as low gas and water vapor permeability. At the initial stage of irradiation the degradation of butyl rubber occurs predominantly via random chain-scission This work aims to the introduction of a new recovery technique for butyl rubber, by using processing via gamma-rays followed by shear. 5 kGy, 15 kGy, 25 kGy, 50 kGy, 100 KGy, 150 kGy and 200 KGy doses were used, in order to study the feasibility of butyl rubber for recycling. Doses within 5 to 25 kGy applied to butyl rubber and pointed toward a less degraded material.

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  • IPEN-DOC 27670

    CAVALCANTE, A.K. ; BATISTA, J.G. ; MAZIERO, J.d. ; FERNANDES, B.V.; VIVEIROS, W.; ROGERO, S.O. ; ROGERO, J.R. ; LUGAO, A.B. . In vitro and In vivo toxicity of Gold nanoparticles synthesized and stabilized with phytochemicals. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Gold nanoparticles (AuNPs) are among the most widely studied metal nanoparticles for biomedical applications. AuNPs can be synthesized by chemical reduction. Several methods for this type of synthesis are described in the literature, one of them is the Turkevich method, which uses sodium citrate (CITR) as a reducing agent. Other methods were developed based on the use of solvent systems during nanoparticle production. Although they are efficient production methods, they are environmentally unviable. In order to address this issue, metabolites present in various plant extracts have been explored for the preparation of different AuNPs. Green nanotechnology is the nanotechnology aspect that aims to develop protocols to generate sustainable products and production processes, in order to minimize the use of toxic compounds. In this study, the phytochemicals chosen as reducing agents and stabilizers for AuNPs synthesis were mangiferin (MGF) and resveratrol (RESV). Due to their ability to interact with biological systems, along with various applications of AuNPs, their toxicity has become one of the most important concerns. Due to the increased production and use of AuNPs, their risk of reaching different environmental compartments and becoming available increases the importance of determining toxicity in various species of biological interest, such as microcrustaceans and fish. Zebrafish is an important animal model used in the areas of developmental biology, genetics, biomedicine, nanotoxicology and is also used in ecotoxicological assays. The aim of the study is to evaluate the toxicity level of MGF (MGF-AuNPs) and RESV (RESV-AuNPs) reduced and stabilized AuNPs in vitro and in vivo by comparing them with the classical AuNPs synthesis method described by Turkvich (CITR-AuNPs). The study has two strands, one of which is to evaluate the level of nanomaterial toxicity using the zebrafish animal model as a preclinical study, and the other to evaluate the level of nanomaterial toxicity using the zebrafish animal model as a study of environmental toxicity. Cytotoxicity assay according to ISO 10993-5, Zebrafish FET TEST according to OECD 236 and Microinjection Assay in Zebrafish embryos. Green nanotechnology has proven to be a valuable tool in the synthesis of AuNPs for toxicity, not requiring the use of solvents and potentially toxic substances. The toxicity of AuNPs varied according to the assay. In the cytotoxicity assay, IC50 was obtained from CITR-AuNPs, whose IC50 was about 72%, which corresponds to the Au concentration of 74.16 µg.mL-1. In FET, RESV-AuNPs caused delays in the hatching process of zebrafish embryos, and it was the only sample that could obtain the LC50 (4.41%, corresponding to the Au concentration of 6,57 µg.mL -1). In the assay in which AuNPs were microinjected into embryos, the concentration causing toxic effect was not found in 50% of the organisms.

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  • IPEN-DOC 27669

    BARTOLOMEI, S.S.; BARTOLOMEI, M.R. ; SILVA, F.A.; OLIVEIRA, A.A.. Use of biodegradable oils as an alternative cooling in quenching treatment. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Ferrous alloys stand out for their use in various branches of the mechanical industry, as they encompass a series of mechanical properties that directly influence their application. For their implementation to be successful, they must have a suitable microstructure, which provides steel with sufficient mechanical characteristics so that it can withstand various types of efforts resulting from its implementation. Heat treatments are responsible for developing this microstructure in a controlled manner, through a set of heating and cooling operations with controlled conditions of temperature, time, atmosphere and cooling speed, in order to change their properties or give them some features. One of the most conventional treatments used worldwide to impart mechanical resistance to steels is the quenching treatment, which consists of heating the metal to austenitization temperature, kept at the same temperature for a certain time and after cooling it rapidly in a liquid medium. great efficiency in the extraction of heat, which can be water, saline solutions, polymeric solutions and oils, in order to form a new microstructure, harder but more fragile than its initial state, called martensite, which after tempering, has its stress-free internal structure, increasing its toughness. The most common cooling medium of the last decades is mineral oil, which due to its viscosity, has excellent capacity to extract heat, but it is a great villain when it comes to environmental issues, an example of this is the increase of water contamination. underground, where mineral oils are the most abundant contaminants present in the analyzed samples of these sources. Due to these and other environmental problems, studies have been developed to obtain an alternative cooling medium as effective as mineral oil, but which has less environmental impact. One solution to this problem is to use compound oils from renewable and biodegradable sources such as vegetable oils. Therefore, this work studies the effects of tempering on SAE 1045 carbon steel and AISI 420 martensitic stainless steel, using biodegradable soy and castor oil as cooling medium. For this, the viscosity of the oils was measured at room temperature and heated to 70 °C, temperatures at which tempering treatments were performed on 10 x 20 x 20mm rectangular section specimens. The specimens were cut, embedded and polished to be characterized by optical micrograph and Vickers microhardness. The results showed that biodegradable oils have excellent stability to bath temperature variation and can be applied over large temperature ranges due to their high flash points. Regarding the hardness and microstructure formed inside the specimen, the vegetable oils were also efficient, presenting values very similar to mineral oil, being soy oil more efficient than castor oil due to its low viscosity influencing hardness of the pieces and also in the formation of martensite. Biodegradable oils have proven to be an alternative.

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  • IPEN-DOC 27668

    MOURA, E.A. ; SANTOS, B.S. ; OLIVEIRA, R.R. ; RODRIGUES, R.C.. Synergistic effect of polylactic acid(PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blend and cellulose nanowhiskers for sustainable packaging applications. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Conventional food packaging is in general, not recyclable, based on practically undegradable petroleum-derived polymers, and consequently not selectively collected. Concerns over their environmental impact and sustainability issues posed by their production and disposal and trends have increased interest and driven the effort to generate biobased and biodegradable packaging to replace or complement the conventional ones. The aims of this work are to investigate the development of biocomposite films composed of biodegradable polylactic acid(PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blend and cellulose nanowhiskers extracted from agro-waste and evaluate their potential use in sustainable food packaging application. Biocomposite films based on biodegradable PLA/PBAT blend containing 1-2 wt. % of cellulose nanowhiskers extracted from agro-waste were prepared by melt extrusion, using a twin-screw extruder machine and blown extrusion process. To evaluate the potential use in food packaging applications, the cellulose nanowhiskers' content on the morphological, mechanical and thermal properties of the as obtained biocomposite films has been assessed. In addition, cellulose nanowhiskers were characterized by TEM, DLS, XRD, and TG. The results showed that cellulose nanowhiskers addition leads to an important increase in thermal degradation temperature, melting enthalpy and tensile properties of biocomposite films. The increases in the melting enthalpy can be attributed to the increase in the crystallinity of PBAT/PLA biocomposite as a result of cellulose nanowhiskers' addition. Morphology and thermal tests were related to the properties of the films and confirmed that cellulose nanowhiskers were homogeneously dispersed into the matrix. Based on the results, this research demonstrated that the use of biodegradable polymer blend and cellulose nanowhiskers extracted from agro-waste represents an interesting alternative for the production of flexible biocomposite films for sustainable food packaging applications and for the development of eco-friendly technologies.

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  • IPEN-DOC 27667

    BARTOLOMEI, M.R. ; ISHIKAWA, O. ; BARTOLOMEI, S.S.; MOURA, E.M. . UV Barrier influence according to the amount of TiO2 in PBAT biodegradable flexible film. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Manufacturing and consumption of polymeric products and packaging continues to grow despite concerns about environmental contamination due to improper post-consumer disposal, causing polymeric waste to emerge in increasingly remote places, polluting seas and soil, affecting flora, fauna and human health. Among these wastes are flexible food packaging. One of the alternatives to reduce this problem is the use of biodegradable materials, such as poly (butylene adipate-terephthalate) (PBAT), but the properties of this material do not meet all the needs of a food packaging, focus of this work. Additives and / or fillers must be added to improve the properties of this polymer, such as mechanical, thermal and barrier properties. One of the important features of a food packaging is the UV light barrier, as many products have shortened shelf life due to interaction with light. This work studies the effect of the addition of titanium dioxide (TiO2) particles to improve UV light barrier in biodegradable flexible PBAT films, with clay addition to improve mechanical properties. The films were obtained by melt processing so that the application is industrially and economically viable. For this, known amounts of TiO2 (0.1, 0.2 and 0.3 wt%) were added in a poly (vinyl alcohol) (PVA) solution, along with 0.5 wt% organophilized light green clay. This mixture was sonicated, poured onto PBAT pellets and oven dried. Then, the particle coated pellets were processed in a twin screw extruder, cooled and pelleted. Then the flexible film was produced in a flat die single screw extruder, thus producing 4 nanocomposites (PBAT + 0.5wt% Clay; PBAT + 0.5wt% Clay + 0.1wt% TiO2; PBAT + 0.5wt% Clay + 0.2wt% TiO2; PBAT + 0.5wt% Clay + 0.3wt% TiO2). The results of X Rays Diffraction (XRD), Scanning Electron Microscopy (SEM) and tensile test showed that the clay was exfoliated in the polymer matrix, allowing improvements in the mechanical strength and elongation of the films. UV-vis absorption assays showed that the higher the TiO2 concentration the higher the UV barrier.

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  • IPEN-DOC 27666

    BARTOLOMEI, S.S.; BARTOLOMEI, M.R. ; MOURA, E.M. ; WIEBECK, H.; OLIVEIRA, R.R. . Effect on flame propagation in recycled expanded polystyrene with flame retardant/white clay/titanium dioxide nanocomposite. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Polystyrene is widely used in construction due to its properties such as low density, heat resistance, durability and ease of processing and molding. However, it is highly flammable, releases a lot of heat and toxic smoke when exposed to a flame. However, in order for a material to be applied in habitable indoor environments, it must comply with fire safety standards, which predict the behavior of materials during their burning. Halogenated flame retardants have been used to reduce the spread of flame, but they are toxic and polluting, so more environmentally friendly products are being developed. Polymeric nanocomposites, formed by inorganic nanoparticles, have many advantages in flame retardation, such as low heat release rate, low smoke and toxic gas production. Alternatively, the organofilized, exfoliated or polymer-intercalated montmorillonite clay (MMT) can be used to form a nanocomposite with greater flame resistance. However, for the clay to achieve the results required by the standards, it is necessary to add a large amount of particles, which generates agglomerates in the material and losses in the mechanical properties. Therefore, the use of clays to improve flame resistance to the material must be accompanied by the use of other flame retardants. Thus clay will provide reduction in flammability and secondary flame retardant will provide ignition resistance. The addition of other particles, together with clay, can corroborate with the reduction in flame spread of the material, with titanium dioxide being used to increase thermal stability, UV light stability, mechanical properties as well as reduction in flame spread. In this work expanded polystyrene (EPS) from construction waste, with flame retardant in its composition, was recycled and plasticized with glycerol. In this polymeric matrix was added white clay and titanium dioxide in order to maintain the flameproof properties and improve the mechanical and thermal properties of the material. The results showed that it is possible to recycle EPS and maintain flame self-extinguishing through the material even in the presence of glycerol as plasticizer. The addition of white clay improved the mechanical properties of the material and increased thermal stability, but impaired the fire behavior of the material, ceasing to self-extinguish the flame immediately after extinguishing the external flame. Titanium dioxide (TiO2) kept the mechanical and thermal properties unchanged and reduced flame propagation in the specimen when compared to the results of clay nanocomposite.

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  • IPEN-DOC 27665

    FUNGARO, D.A. ; CARVALHO, F.B. ; ROVANI, S. ; SANTOS, J.. Effect of experimental variables on the extraction of nanosilica prepared by sugarcane bagasse ash. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Sugarcane bagasse is one of the important biomass sources in Brazil, which is used as a fuel in the sugar industry. As a result, a large quantity of ash is generated and creates a serious disposal problem. The waste bagasse ash can be used as a valuable material to obtain nanosilica. Initially, NaOH was mixed with sugarcane bagasse ash (ash:NaOH 1:2 w/w) and the resultant mixture was fused at 350 °C for 30 min. Next, sodium silicate was solubilized in water and nanosilica was produced by neutralizing with acid. The structure, properties and yield of silica produced is strongly influenced by the extraction method used. Therefore, the silica extraction was conducted using various type of acid (hydrochloric, sulfuric and acetic), acid concentration (0.5; 4.0; and 8.0 mol L-1) and gelation pH (2, 4 and 7 for hydrochloric and sulfuric acids and 4, 5 and 7 for acetic acid). The synthesized nanosilica characteristics were studied using various techniques. Experimental results showed that hydrochloric acid and sulfuric acid produced nanosilica materials with similar yield and purity in each different process parameter. The production of nanosilica particles with the addition of acetic acid was the least favorable under the study conditions, probably due to its weak acid characteristic. The purity of all the synthesized silica nanoparticles is in the range of 94-98% and impurities such as sulfur and iron were presents as main minor compound. The study reveals that the industrial waste material sugarcane bagasse ash acts as an alternative source for the production of nanosilica powder widely used in areas such as ceramics, chemicals, catalysis, chromatography, energy, electronics, coatings, stabilisers, emulsifiers and biological sciences.

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  • IPEN-DOC 27664

    PARRA, D.F. ; LIMA, V.d. ; LUGAO, A.B. ; COTRIM, M.H. . Synthesis and characterization of encapsulation of silver nanoparticles with luminescent methyl polymethacrylate (PMMA). In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Rare earths have improved their importance owing to optical properties not only in the research area, but also in industrial and technological areas. Due to it higher luminescent intensity, Eu3+ complexes are among the most studied rare earth complexes that present luminescence, due to the structures of their energy levels. Combination with high molar absorptive ligands can promote a high emission of the Eu3+ ions. The present study concerns to luminescent doped polymers from methyl polymethacrylate (PMMA) used as a matrix for the development of luminescent films. The rare earth complex [Eu (tta)3 (H2O)2] was synthesized and used as a precursor for the synthesis of the secondary complex [Eu (tta) 3 (TPPO)2]. Silver nanoparticles synthesized and encapsulated in luminescent polymeric system showed distint luminescence behavior in the presence of those nanoparticles. After synthesis, the films were characterized. Investigation of the thermal behavior used differential exploratory calorimetry (DSC) and thermogravimetric analysis (TGA) techiniques. The characteristic fine emissions of the metal ion from the 5D0 ? 7FJ transitions (J = 0-4) indicated the incorporation of Eu3+ ions from both complexes in the matrix. The films showed the increase of the luminescence intensification of secondary complex in relation to the precursor complex. When encapsulating the silver nanoparticles to the luminescent systems, the luminescence intensity of these materials increased under conditions of low concentrations of the complex.

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  • IPEN-DOC 27663

    CARNEIRO, F.W. ; KAWABATA, V.J. ; JACOVONE, R.M. ; ANGNES, L.; GARCIA, R.H. ; SAKATA, S.K. . The synthesis of palladium nanoparticles by electron beam into graphene oxide and its electrochemical behavior. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: In this work, graphene oxide (GO) was synthesized by the modified Hummers method and was used as support for palladium nanoparticles to study its electrochemical behavior. The main objective was the incorporation of Pd on the graphene oxide by the electron beam irradiation at 40kGy and 80kGy doses. The GO-Pd nanocomposite was characterized by thermogravimetry analysis (TGA), X-ray diffraction (XRD), electron transmission microscopy (TEM), zeta potential analysis and cyclic voltammetry (CV). The results were satisfactory, indicating success in incorporating the metal in the GO surface. CV studies were conducted using screen printed electrode modified with nanocomposite, SPE/GO-Pd, at a scan rate of 50 mVs-1, potentials range from -0.5 V until 1.0 V in KCl medium (0.05 mol.L-1) adding aliquots of 4 mmol L ?1 ferricyanide solution and its results showed a linear increase in the current. It can therefore be inferred that palladium /graphene oxide nanocomposites have a potential for sensors.

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  • IPEN-DOC 27662

    KAWABATA, V.J. ; CARNEIRO, F.W. ; JACOVONE, R.M. ; ALMEIDA, E.V. de; GARCIA, R.H. ; CORIO, P.; SAKATA, S.K. . The synthesis of magnetite/reduced graphene oxide nanocomposites by electron beam for eletrocatalysis application. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: This work presents the synthesis of magnetite/reduced graphene oxide nanocomposites (MrGO) via electron beam. The graphene oxide (GO) was prepared according to a modified Hummers’ method and it was characterized using X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Raman spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), zeta potential analysis and cyclic voltammetry (CV) were used in order to investigate the structure and properties of MGO. The data showed GO was reduced using 40 kGy. The CV was performed by applying a MrGO layer on the working electrode of a screen-printed carbon electrode, at a scan rate of 50 mVs-1, potentials range from -0.5 V until 1.0 V in KCl medium (0.05 mol.L-1) adding aliquots of 4 mmol L ?1 ferrocyanide solution. Its results show a similar electrochemical response from both samples (maximum current: 45?A). It can therefore be inferred that magnetite/reduced graphene oxide nanocomposites have a potential for electrocatalysis application.

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  • IPEN-DOC 27661

    NOTARIO, A.O.; RIELLO, F.N. ; FERREIRA, K.d.; MEDEIROS, E.S.; FILHO, L.G.. Screen-printed electrodes functionalization using polimeric matrices. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Biosensors are analytical devices able of converting a biological response into a signal of another nature. In electrochemical biosensors electrode functionalization is a fundamental step. The surface of the electrode, where the interaction with the biological sample occur, must be properly treated so that the signal can be captured in the best way possible, without noise interference and for reproducibility. We aim in this work to use polymeric structures, called blanket, to stabilize the surface of screen-printed electrodes. The blankets are composed of hydrophilic and hydrophobic polymers blend enriched with nanomaterials and were manufactured using the solution blow spinning (SBS) technique. The blankets were placed in contact with the electrode surface and the functionalization by polymer deposition was induced through the current flow. Subsequently, the modification was validated from voltammetry readings and impedance spectroscopy. Scanning electron microscopy showed that there was no change in the microscopic surface of the treated electrodes. However, the blankets were able to improve the reading signal, increasing the active area and current flow and homogenizing the readings between the electrodes. These observed effects may be related to a chemical change in the electrodes and not a physical one. The strategy presented here has the advantage that the polymeric matrices are easy to obtain and inexpensive and can be enriched with various materials. Ensuring that the electrode functionalization step is efficient is essential for the construction of a biosensor, as it also ensures that the capture molecules deposit in a similar manner in each repetition. Finally, this standardization step enables new platforms to be built for disease diagnosis and detection of specific targets.

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  • IPEN-DOC 27660

    RIELLO, F.N. ; NOTARIO, A.O.; GOULART, I.B.; GOULART, L.R.. Electrochemical immunosensor using magnetic capture for disease diagnosis. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Immunosensors are small devices that use biological reactions, relying on antigen-antibody binding to form an immune complex. Methods involving this detection have shown great possibilities for the diagnosis of diseases, but there are still some limitations. In a search for new techniques to increase specific recognition between biomolecules and electrode surface adhesion with faster, lower cost and portability for point-of-care tests, an antibody-coupled magnetic nanoparticle capture system was developed in order to detect antigens in an electrochemical biosensor. Mycobacterium leprae samples were used as an experimental model of more accurate diagnostic tools for this disease. Magnetic iron oxide (Fe3O4) nanoparticles were bioconjugated by covalent binding with M. leprae specific antibody (anti-PGL-I) using EDC promoting direct binding and NHS for stability. Slit-skin smear from leprosy patients with different bacillus concentrations and healthy contacts (negative control) previously quantified by real-time PCR (qPCR / RLEP) were incubated with the bioconjugate and adsorbed on the modified screen-electrode work area. The readings were taken in cyclic voltammetry with portable potentiostat support electrolyte and the PSTouch smartphone software was used to interpret the results. Voltammogram curves have qualitatively discriminated positive from negative samples. Quantitative differences were given by means of logarithmic calculations of the highest values of oxidation peaks in cyclic voltammetry and calibrated based on the number of bacilli previously quantified by qPCR. The novel biosensor presented a detection range from 1 to 1,000,000 bacilli. Briefly, our immunosensor was the first successfully prototype demonstrated for M. leprae detection in direct biological samples from patients. The strategy of magnetic antigen capture proved to be efficient by increasing the sensitivity of the test, because this technique allows the recognition and precipitation of specific antigens. Although it has been used for a specific model, this type of sensor can be applied to different types of diagnostics using antigen and antibody recognition, as the methodology used for bioconjugation is not restricted to the antibody used here. It is also efficient for samples that are difficult to process and where the analyte concentration is low. It is important to emphasize that the new biosensor is portable, fast, sensitive, specific, low-cost and ideal for field screening programs.

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  • IPEN-DOC 27659

    GOMES, D.S. . A survey of accident tolerant fuel composed of uranium dioxide sintered with graphene nanoplatalet. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Global energy demanded should grow by 30% between today and 2040, and nuclear capacity will expand on 83%. Forecast scenarios point out that developing countries will invest in increasing their energy capacity by 45%. Today, nuclear power generates around 11.2% of global electricity, also considered as carbon emissions-free. Humanity must face various challenges to nuclear energy production because of safety operations conditions. In 2011, it started strategic plans, as accident tolerant fuel (ATF) sponsored by government agencies, industries, and universities. ATF introduced concepts that represent enhanced thermal conductivity, improved mechanical response, and radiation stability. It should replace the conventional UO2, also extend the copy time for accident scenarios. Nowadays, it grows the application of carbon materials for electronic devices, aerospace, and nuclear technology. Graphene platelets diffused in UO2 can enhance thermal conductivity around 30% and improve mechanical strength. Using nanocarbon dispersion on the uranium matrix can achieve a lower thermal gradient. The route adopted the spark plasma sintering technique to avoid the graphitization of carbon atoms. At present, the sintering of UO2 may take up a few hours, high temperatures, and energy to furnaces. Graphene is a two-dimensional honeycomb lattice of carbon atoms. Carbon nanotubes are cylindrical shapes, showing diameters of 1-3 nm, formed by graphene sheets. The calculation of the performance of UO2-Graphene used a fuel system with many physical properties updated. UO2-Graphene shows enhanced thermal conductivity and increased the capacity to keep fission gas releases into ceramic fuel.

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  • IPEN-DOC 27658

    GOMES, D.S. ; OLIVEIRA, F.B. . Thermal analysis of nuclear fuel using silicon carbide nanocomposite dispersion in UO2. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: After the Fukushima Daiichi disaster happened in Japan in 2011, it started a global effort to get more tolerant fuels. In 2019, the fleet of power reactors designated for electricity suppliers made up 451 power units, generating around 402 GWe. The nuclear power represents 11.2% of the electricity generated, avoiding about 1.2 GT of CO2. The civilian reactors are operating using the uranium dioxide (UO2) as the fuel, which shows poor thermal conductivity of 7.8 W/m-K at room temperature. The fuel temperatures can reach up until 1500 °C at regular operation. Silicon Carbide Nanotube (SiC-CNT) dispersed in the UO2 matrix containing 5 to 20% vol of SiC-CNTs permits to increases the thermal conductivity. The novel fuel concept improves the thermal conductivity of 30% with the addition of 5% of silicon carbide. The fuel pellet UO2-SiC/CNTs are sintered using Spark Plasma Sintering (SPS) with a hold time of 5 minutes, at 1300 °C, and a pressure of 40 MPa. The fuel mixture shows a better density, low porosity, and acceptable grain size distribution compared to traditional sintering routes. It simulated the fuel mixtures using fuel performance code FRAPCON adapted to the thermals and mechanic properties of compounds. This study showed the possibility of increasing the safety margins of nuclear fuel using the addition of a small fraction of nanocomposite.

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  • IPEN-DOC 27657

    MOURA, E.A. ; SANTOS, B.S. ; ISHIKAWA, O. ; SANTANA, J.G. ; BARTOLOMEI, M.R. ; OLIVEIRA, R.R. . Graphene oxide nanosheets as fillers for thermoplastic-matrix nanocomposites. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Recent studies have shown that the synthesis of graphene oxide (GO) by chemical oxidation of graphite followed by its reduction is one's the most promising routes to prepare remarkable polymer/graphene nanocomposite materials with significant improvement of properties compared to the base polymer. The addition of a very small amount of reduced graphene oxide (RGO)in a polymer can enhance its properties, with respect to electrical conductivity, barrier resistance, stiffness, abrasion resistance, mechanical resistance, and fire retardancy. Numerous approaches have been established to prepare RGO from the desoxygenation of GO. This work presents the synthesis of graphene oxide by chemical oxidation of graphite followed by its photoreduction in aqueous dispersion using UV radiation and highlights some examples of RGO/thermoplastic-matrix nanocomposites prepared by melt processing. To evaluate the potential application of thermoplastic composites prepared, the RGO's content on the morphological, mechanical and thermal properties of the as-obtained nanocomposites has been assessed. In addition, GO/RGO nanosheets were characterized by ATR–FTIR, XRD, Raman, and FE-SEM. According to the results, it can be inferred that the addition of RGO leads to a remarkable improvement in the performance of thermoplastic-matrix nanocomposites and offers a competitive solution for various potential applications.

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  • IPEN-DOC 27656

    PARRA, D.F. ; BASSETTI, C. ; KOMATSU, L.G. . Biocide effects of f nanoparticles of ZnO and ZnO-doped-Ag application in polymeric blend of HMSPP/SEBS. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: In this study, the nanoparticles of Zinc oxide (ZnO) and Zinc oxide doped with Silver (ZnO/Ag) were synthesized in laboratory. The incorporation of these nanoparticles in the blend of High Melt Strength Polypropylene (HMSPP) and Styrene-Ethylene/Butadiene-Styrene (SEBS) was carried by melting process. The obtained materials were evaluated by X-ray diffraction (XRD), Raman Spectroscopy, Differential Scanning Calorimetry (DSC), biocidal tests against the bacteria E.coli and S.aureus following the JIZ 2801 standard. The nanoparticles sized between 100-200nm have spherical form. HMSPP / SEBS / films incorporated with the nanoparticles AgNPs / ZnO showed biocidal effect against the bacteria E.coli and S.aureus.

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  • IPEN-DOC 27655

    KOMATSU, L.G. ; OLIANI, W.L. ; LUGAO, A.B. ; PARRA, D.F. . Synthesis of TiO2-doped- Ag for biocide activity on SEBS/PP applications. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Antimicrobial activity represents a challenge for scientific community. Polymer processing conditions impose temperature limitation for stability of biocide nanoparticles. In the present work, we evaluate TiO2-doped-Ag synthesized in laboratory, utilizing P25 Degussa Titanium Dioxide as precursor. The main proposal is to improve the incorporation of Ag on TiO2. The nanoparticles was tested by reduction of colony units formation (CFU)(%), Dynamical Light Scattering (DLS) and Zeta potential values. On CFU tests, all samples showed biocide properties. The samples showed biocide effect on E.coli and S.aureus bacteriae. The same nanoparticle was tested after sterilization under gamma irradiation, and showed an increase on biocide effect against S.aureus bacteria. The obtained biocide material was processed in SEBS/PP to obtain biocide polymeric films. The new material was characterized by: forming colony units (CFU)(%), Differential Scanning Calorimetry (DSC), and Fourier Transformed Infrared (FT-IR).

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  • IPEN-DOC 27654

    BALOGH, T.S. ; KADLUBOWSKI, S.; BONTURIM, E.; LUGAO, A.B. ; VARCA, G.H. . Influence of argon and nitrous oxide on the synthesis of PVP nanogels prepared by gamma radiation. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Nanogels are innovative systems with great potential for use in chemotherapy, disease diagnosis, release of bioactive substances, vaccines, cell culture systems, biocatalysis, in the generation of bioactive scaffolds in regenerative medicine among other applications. The definition of this material can be directly derived from the definition of polymeric gel, that is, a two-component system consisting of a permanent three-dimensional network of linked polymer chains and solvent molecules filling the pores of this network. Its internal structure is similar to that of hydrogels however presents particle size range varying from 0 to 100 nm leading to several advantages. Nanogel production methods involve intramolecular crosslinking that can be achieved using ionizing radiation. This method avoids the addition of any additives allowing the reaction to be carried out in a pure polymer-solvent system and the production of nanogels for biomedical applications free from monomer and crosslinking agents or surfactants. In this work influence of argon and nitrous oxide on the formation of nanogels by gamma irradiation has been evaluated. The samples were prepared in duplicate in multipurpose cobalt-60 gamma irradiator using a 25 mM PVP solution. Samples were irradiated in argon and nitrous oxide conditions with doses from 1 kGy up to 25 kGy with 10 kGy/h dose rate. These samples were morphologically characterized using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) as well as the pristine PVP solution. The mean particle size of the samples and the polydispersity index was performed in equipment Zetasizer Nano ZS - Malvern® and the determination of radius of gyration and molecular weight was performed in equipment Heleos - Wyatt®. It was observed in the conditions evaluated that saturation with argon or nitrous oxide promoted similar results except for 25 kGy dose. At this dose larger mean particle size and radius of gyration were observed in the sample saturated with nitrous oxide.

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  • IPEN-DOC 27653

    NASCIMENTO, A.C. ; PASSOS, P.d. ; LIMA, M.M. ; GALISTEO JUNIOR, A.J.; VIEIRA, D.P. . Mouse mioblast (C2C12) spheroids structured using paramagnetic iron nanoparticles as an in vitro culture system of Toxoplasma gondii tachyzoites. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Tridimensional cell culture techniques became essential for understanding physiological processes that are obliterated or fainted in conventional bi-dimensional cultures. These techniques are prone to produce more realistic modeling of the complex environment of living tissues, leading to much better understanding of mammalian tissue organization. This work used magnetic levitation of cell aggregates (spheroids) by adsorbing iron nanoparticles to C2C12 mouse (Mus musculus) mouse line cells (ATCC # CRL-1772), which are suspended with magnetic fields. The cells formed three-dimensional bodies that were cultivated suspended in the air-liquid interface. Magnetite (Fe3O4) nanoparticles with mean diameter of approximately 50 nm were produced by an alkaline coprecipitation methodology under reduction by microwave energy. Composition and size of crystallites were determined by DRX analysis. Adsorption on cell membranes occurred after functionalization with poly-L-lysine. Work concentrations of nanoparticles did no induce cytotoxicity in C2C12 monolayer cultures. Transmission electron microscopy of spheroid sections showed some findings morphologically compatible to the shape of reproductive intracellular vacuoli of T.gondii after cell invasion, demonstrating an interaction of cells with parasites in three-dimensional models.

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  • IPEN-DOC 27652

    MOREIRA, R.P. ; FELINTO, M.C. ; BRITO, H.F.. Synthesis of tungstates nanoparticles with luminescent properties. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Nanomaterials doped with rare earth ions have attracted great attention due to their unusual optical and electronic properties which leads these materials to be looked at as potential materials for application in the fields of high performance luminescent devices, lighting, magnets, catalysts, medical diagnostics, markers biological luminescent, etc. The advantages of using lanthanide ions as luminescent markers are numerous: it is a safe, low cost method, has higher specificity, the tests are more sensitive and the luminescence can be measured quickly, with a high degree of sensitivity and accuracy. [1-3] Among the methods used in obtaining nanocrystals can be mentioned: coprecipitation, sol-gel, microemulsion, microwave, polymer precursor, among others. In recent years, the polymer precursor (Pechini) and combustion methods are being used with greater emphasis due to the race to obtain nanoparticulate compounds, with homogeneous morphology in order to improve the performance of luminescent materials with application in nanotechnology. The Ba(1-x)WO4:xEu3+ powders were synthesized using the Pechini method, where the solutions of the salts of the Ba2+ and Eu3+ percussors in the form of NO3 ions. The 1: 4 citric acid and ethylene glycol solutions were added in the form of heat and heat to form a polymer resin, the pH being adjusted to 7 with ammonium hydroxide so that a brown, transparent resin . This resin was heated at 300°C for 2 hours, resulting in a black mass, which was prepared for the preparation of the precursor in powder form. The precursor was calcined at a preset temperature of 900°C for the production of barium tungstate.

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  • IPEN-DOC 27651

    ROCHA, M.d. ; ANDRADE, D.A. ; MOREIRA, P.G. ; STEFANIAK, I. ; MARTINS, J.G. . Investigation on the improvement of thermal properties of TiO2 nanofluids. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: This work aims to investigate the thermophysical properties of TiO2 nanofluids in the water base experimentally and also comparing results with existing literature data and theoretical models. Studies reveal that nanofluids present increasing in thermal conductivity and other important properties related to the heat transfer capacity compared to the base fluid. In this way, it can be classified as promising fluids for heat transport applications. As the proposal is to use it in high thermal flux systems, the survey of experimental measurements was performed to verify whose of the main parameters have more influence over such properties. Thermal conductivity, viscosity, surface contact angle and some visualization of nanoparticles in SEM were carried out in order to understand the nanofluids properties modifications. The TiO2 nanofluids in water base solutions were prepared for this study using the ultrasonic dispersion technique for three distinct volume concentrations: 0.1%, 0.01%, and 0.001%. Samples were initially prepared using an ultrasonic disrupter to make a homogeneous solution. This is an important step in sample analyses concerning the homogeneity influence on thermal conductivity measurements. With all samples prepared, some steps were followed to ensure the dispersion of nanoparticles and thus obtaining more accurate results Nanofluids samples were visualized in a scanning electron microscope (SEM) JEOL, model JSM 6701F at IPEN. Figure 2 shows the TiO2 nanoparticle's image observed. Preliminary tests for determining the thermophysical properties of nanofluids were: density, thermal conductivity, viscosity and surface contact angle. Concentration and temperature effects were investigated in preliminary tests for measurement of the thermal conductivity of nanofluids: this step consists of measuring the thermal conductivities and viscosities of nanofluids for all concentrations (0.001%, 0.01% and 0.1% vol.) at 15°C, 25oC and 35oC. ASTM D5334-08 (2008) describes the standard procedure for determining thermophysical properties and is based on the classical Linear Probe Method also known as the Transient Hot-Wire Method.

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  • IPEN-DOC 27650

    BATISTA, J.G. ; FREITAS, L.F. ; CRUZ, C.C. da ; LUGAO, A.B. ; RODRIGUES, A.S. ; SANTOS, L.O. ; PIRES, M.A. . Green nanotechnology: stability and interactions of gold nanoparticles obtained with Annona muricata extract. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Cancer is among the diseases with the highest mortality rate, with more than 100 different types that occur due to mutations in the genetic material of cells. It is the third leading cause of death worldwide after cardiovascular and infectious diseases. In addition, the number of diseases caused by oxidative stress that results from an imbalance between the formation and neutralization of oxidizing species is increasingly perceived. Oxidative stress is initiated by free radicals and their interactions with biological macromolecules, such as proteins, lipids and DNA, healthy human cells and cause damage to proteins and DNA, with lipid peroxidation. These changes contribute to cancer, atherosclerosis, cardiovascular and inflammatory diseases. All cells are exposed to oxidative stress and therefore oxidation and free radicals play an important role in the development of cancer. Medicinal plants have a special place in cancer management. Several cancer researchers have been carried out studies using traditional medicinal plants, to discover new therapeutic agents that do not have side effects associated with chemotherapeutic agents. Studies using the extract of Annona muricata L., popularly known as araticum, have demonstrated potential anti-inflammatory and anticancer action, due to its antioxidant and immunological properties. The objective of the present work was to develop gold nanoparticles using Annona muricata L. dry extract and verify their physical-chemical characteristics, such as size, shape, and stability. The results obtained show that it is possible to synthesize gold nanoparticles with potential applications in medicine using the extract of araticum. Characterization was performed using the techniques of UV-Vis spectrophotometry, dynamic light scattering (DLS), transmission electron microscopy (TEM). The in vitro stability study of the gold nanoparticles synthesized with the araticum extract was carried out for thirty days. The nanoparticles showed to be stable in different media during this period and the monitoring was done by spectrophotometry.

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  • IPEN-DOC 27649

    YAMAGATA, C. ; RODAS, A.C.; HIGA, O.Z. ; MELLO-CASTANHO, S. . Synthesis and characterization of a bioactive silicate ceramic from SiO2 nanoparticles. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Sol-gel and co-precipitation techniques have been used for synthesis of multiphase silicate ceramic from SiO2 nanoparticles. Non-aggregated colloidal SiO2 nano particles were initially prepared from a sodium silicate solution, by surfactant template sol-gel method. Afterward, calcium and magnesium hydroxides were co-precipitated on colloidal SiO2 nanoparticles surface. CaO-MgO-SiO2 sintered ceramic obtained from the synthesized powders were characterized by SEM,XRD and FTIR. In vitro tests were performed by soaking the sintered samples in the simulate blood fluid (SBF, at pH 7.25 and 37 ?C) to observe its bioactivity. After 7 days of immersion in SBF, the FTIR spectra analysis revealed that the material is bioactive, by the formation of hydroxyapatite on the surface of the sample. No toxic effect was found in the cytotoxicity tests with CHO (Chinese hamster ovary) cells.

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  • IPEN-DOC 27648

    LIMA, V.d. ; PARRA, D.F. . Study of luminescent effects on PMMA films with Eu3+/Ag nanoparticles. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Lanthanides, which are part of rare earths, have attracted attention due to their optical properties, not only in the field of research, but also in industrial and technological areas. Eu3+ ions are among the most studied of rare earth complexes because they have higher luminescence due to the structures of their energy levels. Combination with high molar absorptive ligands may promote higher emission of rare earth ions. The luminescent polymer system used as markers was obtained from doping with rare earth complexes, incorporating a Europrium complex containing trifluoroacetonate anion (TTA) in the process of encapsulating silver nanoparticles in methyl polymethacrylate (PMMA). The study will show that by introducing metallic nanoparticles, such as silver, it is possible to enhance the emission intensity in the luminescence processes of lanthanide compounds. The study of luminescence properties was performed by the spectrofluorimetry technique, showing that by introducing silver nanoparticles it will be possible to verify an increase of luminescence of the material in low concentrations of Europium complex. It will also be possible to observe an increase in material thermal stability through Thermogravimetric Analysis (TGA / DTG) performed under N2 atmosphere.

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  • IPEN-DOC 27647

    TAKARA, E.M. ; SOUZA, J.B. de ; CARVALHO, E.F.U. ; SILVA, A.S. . Kinects and factors on chemical dissolution of aluminum alloy AA6061 in NaOH alkaline media. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Nuclear Medicine is the Field of science that uses radioactive materials in order to diagnose and treat human body deceases. One of the most used radioisotopes for images diagnose purpose is the metastable technetium-99 (99mTc) because of its low decay half life (6 hours) and energy emission of 140keV that ensures low exposition time with the capacity of generating high quality images. The 99mTc is generated by the molibdenum-99(99Mo) radioactive decay during about 66 hours. The 99Mo is fabricated via nuclear fission of low encriched uranium (LEU) through plate irradiation targets (UAlx). The irradiation target cladding is made of Aluminum alloy AA6061 and its substrate is composed by 235U powder scattered in an AA1050 matrix. In general, studies are made targeting the prevention of corrosion mechanisms but the chemical dissolution in alkaline media, under hot cells, are one of the steps required for the post-processing methods of irradiation targets The time spent after irradiation is an important factor because the half life radioactive decay of the produced radioisotopes is relative short, then the procedures of dissolution, extraction, purify and distribution must be optimized in order to increase efficiency. This work presents a study of the factors impact involved on the chemical dissolution of the cladding aluminum alloys (temperature, NaOH solution concentration and dissolution time) as well as the kinects of the process associating it with the formation and destruction of oxides using electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). It was found that the involved parameters contribute individually more effective and that there is no relevant association between the factors. Solution temperature showed to be the most influent factor following by exposition time. It was presented a equivalent circuit model which demonstrates the reaction kinects and the growing of passive layers that slow down the process before it turns up into a soluble phase.

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  • IPEN-DOC 27646

    LANGE, C.N.; PELEGRINO, M.T.; KOHATSU, M.Y.; SEABRA, A.B.; BATISTA, B.L.; MONTEIRO, L.R. ; URZEDO, A.L.; JESUS, T.A.; GOMES, D.G.; OLIVEIRA, H.C.. Copper nanoparticles are an effective tool to increase endogenous nitric oxide and have beneficial effects on lettuce seedlings. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Copper oxide nanoparticles (CuO NPs) have been investigated as a solution for agriculture worldwide problems. CuO NPs are efficiently to inhibit several pathogens and they are been commercially used as nanopesticide. In addition, CuO NPs might be promising for plant growth, development and recovery of degraded soils. The molecular pathway leading to these remarkable features of CuO NPs administration may be related to nitric oxide (NO) signaling. NO is a molecular messenger related to abiotic and biotic stress responses. CuO NPs may increase copper ion in plant. The increase of copper ions is well known to decompose S-nitrosothiols (RSNO) and generate NO. Our purpose in this study was to investigate the effect of CuO NPs on lettuce (Lactuca sativa L.) seedlings and the role of NO in its process. CuO NPs were synthesized using green tea extract as the reductor agent. They showed an average size diameter of 6.6 ± 0.2 nm, as assessed by transmission electron microscopy (TEM). The lettuce seedlings were exposed to a wide CuO NPs concentration range of 0.2 to 300 µg mL-1 and the germination rate and radicle elongation were analyzed. CuO NPs concentrations under 40 µg mL-1 showed no phytotoxic behavior to lettuce seedling whereas concentrations equal or above 80 µg mL-1 showed moderate to strong phytotoxic behavior. The optimum concentration was found to be at 20 µg mL-1 which showed an enhancement of germination and radicle growth of lettuce seedling. To evaluate the overall oxidative stress of plant, the enzymes catalase (CAT), ascorbate peroxidase (APX), peroxidase activity (POD) and superoxide dismutase (SOD) were analyzed. SOD levels significantly decreased with the increase of CuO NPs concentration. The SOD enzyme is correlated to decrease reactive oxygen species (ROS), thus the observed toxicity in concentration above 80 µg mL-1 may be linked with higher levels of ROS. In addition, we quantified RSNO and nitrite (NO2-), measured by amperometric analysis, which are indicators of NO presence. RSNO and NO2- levels significantly increased with the increase of CuO NPs concentration. CuO NPs administration was effective to increase NO formation in plant. Low levels of RSNO and NO2- were observed to have beneficial effects to lettuce seedlings. Thus, CuO NPs concentration is a crucial factor to assurance its beneficial effect and the NO signaling pathway may have an important role underling this process.

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  • IPEN-DOC 27645

    JACOVONE, R.M. ; COSTA, C.A.; SAKATA, S.K. . Chemical characterization of bacteria: graphene oxide/Ag nanocomposite interactions by atomic force microscopy -infrared spectroscopy. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Atomic force microscopy -Infrared spectroscopy (AFM-IR) is a combined technique that allows nanoscale chemical characterization of biological–materials interactions. In this work, AFM-IR was used to map Escherichia coli in graphene oxide /silver nanocomposite (Ag/rGO). In Escherichia coli, it was observed absorption bands corresponding to amine I at 1660 cm-1 and amide II at 1550 cm-1 from proteins. On the other hand, when these bacteria were exposed to (Ag/rGO) typical absorption bands from carbonyl/carboxyl groups around 1745 and carbon bond around 1620 were also detected, showing the antibacterial activities of (Ag/rGO). The conventional atomic force microscope was used to elucidate the morphologic changes that occurred by internalization of nanocomposite into the bacteria. Atomic force microscopy -Infrared spectroscopy (AFM-IR) is a combined technique that allows nanoscale chemical characterization of biological–materials interactions. In this work, AFM-IR was used to map Escherichia coli in graphene oxide /silver nanocomposite (Ag/rGO). In Escherichia coli, it was observed absorption bands corresponding to amine I at 1660 cm-1 and amide II at 1550 cm-1 from proteins. On the other hand, when these bacteria were exposed to (Ag/rGO) typical absorption bands from carbonyl/carboxyl groups around 1745 cm-1 and carbon bond around 1620 cm-1 were also detected, showing the antibacterial activities of (Ag/rGO). The conventional atomic force microscope was used to elucidate the morphologic changes that occurred by internalization of nanocomposite into the bacteria.

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  • IPEN-DOC 27644

    RIELLO, F.N. ; VARCA, G.H. ; LIMA, C.S. ; FREITAS, L.F. ; FERREIRA, A.H. ; LUGAO, A.B. . Synthesis and purification of albumin-based nanoparticles crosslinked by radiation. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Protein-based nanoparticles have been proved a promissing alternative for the loading and delivery of chemotherapeutic agents, radiopharmaceutics and other drugs of interests, constituting a less toxic therapeutic option due to its biocompatibility and low or null side effects. The use of radiation to crosslink or form covalent bonds enables the controll of the crosslinking process, without the need for crosslinking agents, as well as provides sterilizations simultaneously, withouth generating toxic compounds or products. The present work targets the synthesis an purification of albumin-based nanocarrier crosslinked by gamma radiation for biomedical applications. For such purpose, albumin nanoparticles were synthesized using BSA at 20% ethanol (v/v) in 50 mM phosphate buffer on an ice bath prior to and after irradiation. Samples were exposed to gamma radiation at a minimun absrobed dose of 10 kGy at 5kGy.h-1 and purified using a SuperdexTM 200 Increase 10/300GL for isolating the crosslinked protein (high molecular weight) from the native BSA. After the purification, the fractions were characterized by electrophoresis, Uv, fluorescence and dynamic light scaterring. The nanoparticles were obtained in the range of 25-40 nm and purified into fractions of high molecular weight and the native ones. The high molecular weight fractions presented increased bityrosine levels if compared to the fraction corresponded to the native BSA. The yields of nanoparticle formation remains to be determined, but our results provided a clear evidence of the formation of radiation-crosslinked BSA nanoparticles and the role of bityrosine in the nanoparticle assembly.

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  • IPEN-DOC 27643

    FRANCISCO, L.H. ; FELINTO, M.C. ; BRITO, H.F.. Hydrothermal synthesis of rare-earth doped nanoparticles for energy conversion and storage. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: In recent years, several classes of rare-earth doped luminescent nanoparticles have been drawing attention due to complex energy converting systems that can be structurally engineered to tune absorption and emission wavelengths, outlining novel materials and applications on photonics [1-2]. In this scenario, this work presents the development of rare-earth doped core-shell SrAl2O4:Eu2+/3+, Dy3+ nanoparticles prepared via hydrothermal synthesis and post-annealed on carbon monoxide reducing atmosphere, which exhibit appealing spectroscopic properties for solar energy conversion and storage. The prepared strontium aluminate phosphors were further amino-functionalized with 3-aminopropyltrimethoxysilane (APTMS) and ?-diketonate rare-earth complexes by microwave assisted synthesis [3], in order to enhance its absorption section and energy-transfer processes within the system. Prepared samples were analyzed by X-ray powder diffraction, which revealed a stable monoclinic phase of pure strontium aluminate accordingly to PDF34-379. Crystallite size was estimated by the Scherrer method, indicating dimensions of about 25 nm. Moreover, standard luminescence spectroscopy results of pure SrAl2O4:Eu2+/3+, Dy3+ showcased characteristic green Eu2+ emission assigned to the 4f65d1?4f7(8S7/2) interconfigurational transition under near ultraviolet excitation. It was also found that amino-functionalized samples display distinguished emission spectral profiles, as Eu2+ emission shifts on ?-diketonate coated samples, suggesting an effective interaction between the inorganic host-matrix, the silica network and the ?-diketonate complexes. Likewise, acquired excitation spectra monitored on Eu2+ emission revealed its characteristic broad band in the ultraviolet region, as well as non-reduced Eu3+ narrow absorption lines. In addition, ?-diketonate S0?Sn transitions were also observed on functionalized samples, unveiling an increasing absorption section under ultraviolet light. Finally, it is highlighted that prepared SrAl2O4:Eu2+/3+, Dy3+ persistent phosphors displayed intensifying characteristic green emission under UV light due to imposed surface modification processes by functionalization. Therefore, as its emission wavelength overlaps with a commonly used dye (N719) in dye-sensitized solar cells, the materials assembled in this work aspire to enhance energy conversion efficiency and storage on such photovoltaic devices.

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  • IPEN-DOC 27642

    NOGUEIRA, K.M. ; VARCA, J.O. ; LIMA, C.S. ; CRUZ, C.C. da ; RIBEIRO, A.H. ; FREITAS, L.F. ; VARCA, G.H. ; LUGAO, A.B. . Development of Lignin/PEO nanofibers by electrospinning technique for tissue engineering application. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Lignin is a renewable carbon source and has been widely explored in different areas over the last years, especially in biomaterials such as dressings and other biomedical devices due its natural origin and low cost. Its chemical structure confers interesting properties such as antioxidant capacity, UV protection, bactericidal action and appropriate adsorption. Poly (ethylene oxide) (PEO) is used in electrospinning to facilitate the formation polymer fibers. The electrospinning technique has been largely explored in the bioengineering area towards designing nanomaterial with minimum defect and high surface area. The present work aimed the development of a lignin/PEO nanofiber by electrospinning technique. In practical terms, lignin/PEO solution was prepared following two different methods. In the first approach, polymer stock solutions were prepared in alkaline water by stirring at 70 °C. In the second, the polymer powders were mixed and dissolved together in dimethylformamide (DMF) under stirring at 80 °C. By both methods, PEO/lignin solutions were prepared at 10, 20 e 30% (w,v) solid content, at the ratios 99/1 and 95/5. For electrospinning parameters, the distance between ejector and plate collector was set to 15-20 cm, voltage to 20 kV and injection flow to 1 mL/h, chamber temperature to 40 °C and 30%. Nanofiber morphology was assessed by scanning electron microscopy and optical coherence tomography. Apparent porosity was measured by classical Archimedes method. Due to higher DMF dielectric constant compared to water, results showed that nanofibers made using DMF presented smaller beats formation and smaller fiber diameter. Nanofibers with higher solid content presented more uniform fibers with larger diameter. Nanofibers with higher lignin concentration presented larger number of beats and higher fiber diameter. However, lignin improved the system porosity in all cases. Further mechanical and biological experiments will be done, nevertheless, the nanofiber developed is a promising material to be applied in tissue engineering.

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  • IPEN-DOC 27641

    MOURA, E.A. ; ISHIKAWA, O. ; MANGIERI, F. ; BARTOLOMEI, M.R. ; BARTOLOMEI, S.S.; OLIVEIRA, R.R. ; FRANCISCO, D.L.; GUIMARÃES, K.. Sonochemical synthesis of reduced graphene oxide: methods and characterization. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: The reduction of graphene oxide (GO) by a safe and eco-friendly route, without the use of harmful chemicals, has drawn much attention as one of the most promising routes to produce graphene nanosheets, a 2D material with excellent electrical and thermal conductivity, optical and mechanical properties. Graphite exfoliation is widely performed by the chemical reduction of GO, which is commonly produced by oxidation of graphite using a strong oxidizing agent by Hummers’ method. This work presents a study of the influence of sonochemical application on synthesis of reduced graphene oxide induced by UV radiation. Commercial graphite powder was used as raw material. Firstly, graphite powder was dispersed into a DMF/deionized water solution and ultrasonicated using a high intensity ultrasonic device for 1 8 hours in other to reduce the particle sizes. After, sonicated graphite samples were frozen for 24 hours and freeze-dried for 24 hours to obtain the powder. Graphite powder obtained with different particle sizes was used to prepared GO through a chemical route. GO prepared was dispersed into a DMF/deionized water solution, ultrasonicated using a high intensity ultrasonic device for 1-2 hours, frozen for 24 hours and freeze-dried for 24 hours. Finally, GO powder samples were dispersed in a mixture of isopropyl alcohol, acetone, and deionized water and irradiated using UV radiation by different irradiation time to obtain reduced GO (RGO). The GO and RGO were characterized by BET, ATR–FTIR, XRD, Raman, TG, and FE-SEM analysis. In addition, graphite samples were characterized by BET, SEM and XRD analysis. The results showed that sonochemical application has a fundamental role in the synthesis of GO nanosheets and RGO. Ultrasonically prepared GO exhibited higher surface area, higher crystallinity and higher oxidation efficiency with many hydrophilic groups. FE-SEM analysis of the GO showed that sonochemical application reduced the aggregated domains and close stacking of sheets on the GO surface and led to obtaining reduced GO with a smooth surface, fewer layers and significant effective surface area.

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  • IPEN-DOC 27640

    LIMA, C.S. ; VARCA, G.H. ; OLIVEIRA, J.R. ; NOGUEIRA, K.M. ; SANTOS, F.A. ; RIBEIRO, A.H. ; LUGAO, A.B. ; FREITAS, L.F. ; ROGERO, S.O. . CMC and PVA hydrogel containing papain nanoparticles for drug delivery. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Four hydrogel formulations of Carboxymethylcellulose (CMC) and Poly (vinyl alcohol) (PVA) were prepared with native papain (AP and BP) and papain nanoparticles (AN and BN) for drug delivery. The formulations were evaluated for their preliminary stability, protein distribution in the matrix and cytotoxicity. Three methods for sterilization purposes were compared: irradiation by 60Co source, electron-beam and UV light. The preliminary stability test confirmed that the system was stable since there was no precipitation or alteration of the organoleptic properties of the samples in the evaluated period. The distribution of proteins in the hydrogel was very homogeneous in all the formulations. Quantification of the enzymatic activity of papain after contact with the gel showed that native papain maintained its activity high (86% and 93% for AP and BP gels, respectively), whereas there was a considerable drop in the activity of the papain nanoparticles to 60.54% and 69.44% for AP and BP gels, respectively. Such loss of activity is attributed to processing and/or process steps. The cell viability assay showed that the polymer matrix shows no cytotoxicity, corroborating with the literature, since the material is biocompatible. Thus, it is possible to affirm that the developed system presents potential for biomedical application, either as a vehicle of papain itself or for the transport of other drugs through complexation with papain nanoparticles. However, the need for further studies of stability, controlled release capacity and biocompatibility is required.

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  • IPEN-DOC 27639

    FREITAS, L.F. ; CRUZ, C.C. da ; BATISTA, J.G. ; VARCA, G.H. ; LUGAO, A.B. ; PIRES, M.A. . Stability of gold nanoparticles in different ionic concentrations and pH: a comparison among synthetic protocols. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: There are several protocols for the synthesis of gold nanoparticles, and lately there is a trend for green methods in order to minimize the environmental impacts. The reduction of gold salts by epigallocatechin 3 gallate, for instance, generates stable and uniform nanoparticles without the use of toxic compounds, and so does the radiolytic synthesis protocol. For medical purposes, proteins like albumin and papain are useful coating agents, providing a better biological effectiveness. Here we present a comparison of different synthetic and protein coating protocols for gold nanoparticles regarding their stability in different NaCl concentrations and pH, aiming for the development of nanoparticles that are able to be administered in physiologic solutions to patients. The nanoparticles were synthesized via EGCG (2 mg mL 1) reduction of gold salt (5 mmol L 1) in phosphate buffer pH 7.0. Those nanoparticles were coated or not with albumin or papain (1 mg mL 1) using mercaptopropionic acid. Other protein coated gold nanoparticles were synthesized radiolytically by mixing 5 mmol L 1 NaAuCl4 with 1 mg mL 1 bovine serum albumin (BSA) or papain and 0.1 mol L 1 tert butanol. The solutions were irradiated with 10 kGy (60Co source, 5 kGy h 1) and the resulting suspensions were stored until use. The suspensions were added in 96 well plates to solutions with different pH and NaCl concentrations, and their absorption spectra were taken periodically to verify their stability. It was observed that BSA gold nanoparticles synthesized by both protocols were stable in concentrations of NaCl varying from 0.1% to 14.4% up to 72h. The papain gold nanoparticles synthesized by both protocols were stable in concentrations of NaCl varying from 0.1% to 14.4% up to 48h, but in 72h there was evidence of instability in the lowest and highest NaCl concentrations. The nanoparticles coated just with EGCG (without proteins) were stable in all NaCl concentrations and times, except in the highest concentration after 72h. Regarding the pH, BSA gold nanoparticles and papain gold nanoparticles synthesized radiolytically, as well as EGCG gold nanoparticles were stable at least in pH varying from 5 to 11, in all times analyzed. In conclusion, all the nanoparticles tested are able to be administered to patients in physiological solutions, which have pH around 7.4 and NaCl concentrations around 0.9%, without the risk of aggregation and loss of biological activity.

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  • IPEN-DOC 27638

    MORAES, T.S. ; FERREIRA, J.C. ; BERGAMASCHI, V.S. ; SPINACE, E.V. . Core-shell catalysts for ethanol steam reforming reaction. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Hydrogen can be produced from the steam reforming (SR) of biomass-derived liquids such as bioethanol. The SR of ethanol for hydrogen production has several advantages. However, one of the main barriers to the commercialization of this technology is the deactivation of the catalysts due to the formation of carbon. Therefore, the development of catalysts that are stable and resistant to carbon formation is necessary. Several strategies have been used to avoid the deposition of carbon on the surface of the catalysts. Cerium oxide, at high temperatures or in the presence of reducers, can easily change oxidation state to form a non-stoichiometric oxygen deficient oxide. This oxide has a strong tendency to remain in the fluorite structure even after considerable oxygen loss, stabilizing the structure with a high number of oxygen vacancies. Other approach to minimize coke formation is to control the size of metallic particle through modifications in the catalyst structure. According to the mechanism reported in the literature, carbon formation in these reactions are favored in large sizes of metal particle. Therefore, controlling particle size is essential to reduce carbon accumulation on the catalyst surface during ethanol reforming reactions. One strategy for inhibiting the sintering process of metal particles in catalysts is the development of core-shell catalysts. These catalysts feature a metal core covered with an oxide layer, which gives them unique characteristics. The core-shell structure also accelerates the transformation processes of the carbon formed at the metal-oxide interface, favoring the gasification reaction and consequently its elimination in the form of CO2. Das et all have synthesized an innovative sandwiched core-shell structured Ni-SiO2@CeO2 catalyst that showed high activity and stability at dry reforming of biogas with negligible coke formation. The aim of this work is to investigate the performance of the structurally modified Ni-SiO2@CeO2 catalyst in the form of a sandwiched core-shell to inhibit the formation of carbon and increase the stability of the catalysts in the SR of ethanol reaction. This new form of catalyst synthesis has proved very efficient in other reactions but is still very little studied in the ethanol SR reaction. Silica nano-spheres were synthesized by the Stöber method and Ni-SiO2 catalysts were prepared via a Ni-phyllosilicate precursor route. Ni-SiO2@CeO2 will be prepare using the fresh Ni-phyllosilicate spheres that will be coated with a thin layer of CeO2 using a precipitation method. Silica nano-spheres and Ni-SiO2 were calcined at 1273 K for 1 hour with air. Samples were analyzed using transmission electron microscope (TEM) and x-ray diffraction (XRD). SR of ethanol was performed in a fixed-bed reactor at atmospheric pressure. Prior to reaction, catalysts were reduced under pure hydrogen at 923 K for 1 h. The reactions were carried out at 673K and H2O/ethanol molar ratio of 3.0.

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  • IPEN-DOC 27637

    BRITO, H.F.; FELINTO, M.C. ; FRANCISCO, L.H. ; SAULA, M.S.; MERIZIO, L.G.. Nanoparticles presenting the phenomenon of luminescent persistence make the difference in biological applications. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: The persistent luminescent materials are an important class of light-induced energy storage materials, which have undertaken a long development process. Recently, there has been increasing interest in employing long persistence luminescent nanoparticles (LPLNPs) for in vivo imaging. Because the long afterglow of these nanoparticles can last for several hours after they are excited in vitro, real-time in vivo imaging can be achieved after injection without requiring any external illumination source. Thus, the SNR can be significantly improved by removing the background noise originating from in situ excitations. Moreover, the afterglow luminescence of near-infrared (NIR)-emitting long-persistence luminescent nanoparticles (NLPLNPs) (the afterglow wavelength varies from 650 nm to 900 nm) falls within the tissue transparency window, where light attenuation is largely due to scattering rather than absorption, which is advantageous for long-term in vivo imaging with deep penetration and a high SNR1-3. In this work, we will be discussed the synthesis of these LPLNPs, the characterization and the luminescent properties especially the persistent luminescence intensity and lifetime that are the two important parameters to evaluate the persistent luminescent properties of materials. It was expected the materials to have a very high luminescence intensity and long persistent lifetime. The development of rare-earth doped core-shell SrAl2O4:Eu2+/3+, Dy3+ nanoparticles prepared via hydrothermal synthesis and p-st-annealed on carbon monoxide, in reducing atmosphere, or materials like Li1,6M1,6Sn2,8O8:R3+ (M2+: Mg, Zn and Cd; R3+: Cr, Nd, Yb), etc prepared by microwave-assisted solid-state reaction, ceramics method and co-precipitation reaction generate materials with efficient persistent luminescence and will be discussed in terms of electronic structure and syntheses methodology. Moreover, standard luminescence spectroscopy results of pure characteristic green Eu2+ emission assigned to the 4f65d1?4f7(8S7/2) interconfigurational transition under near-ultraviolet excitation. Some of these materials have special behavior and present persistent luminescence in the near-infrared, NIR, which is very important in terms of biological application point-of-view.

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  • IPEN-DOC 27636

    FELINTO, M.C. . Nanocrystals of BaWO4:Dy3+ and SrWO4:Dy3+ synthetized by green chemistry method. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Nowadays, the investigation of oxide based light emitting materials for white light emitting diodes (w-LEDs) or device applications have generated interest due to the advantages such as long lifetime, low energy consumption, high luminescence efficiency and environmental friendliness [1]. These qualities make them a strong candidate for the solid state lighting, display devices, optoelectronic devices and light-emitting diodes (LEDs). In this work, we present results of Dy3+: BaWO4 and Dy3+: SrWO4 that present luminescence close to white color (Figure 1) left. They were synthesized using co-precipitation method. The emission spectra exhibit four emission transitions centered at around 486 nm, 576 nm, 665 nm and 760 nm corresponding to the transitions 4F9/2?6H15/2 (blue), 4F9/2?6H13/2 (yellow) 4F9/2?6H11/2 and 4F9/2?6H9/2 6F11/2 (red) respectively. Among these transitions 4F9/2?6H15/2 and 4F9/2?6H13/2 are observed to be strong whereas 4F9/2?6H11/2 transition is found to be relatively quite weak. The 4F9/2?6H13/2 transition is hypersensitive in nature and is strongly influenced by the environment around the Dy3+ ion site. It is observed in the luminescence spectra of these materials that the electric dipole transition is dominant compared to the magnetic dipole transition. The CIE diagram show emission close to white (Fig.1 right) for the five composition with little distortion of the color showing the influence of dopant concentration in the color of the emission. Figure 1. Dy3+: BaWO4 under UV excitation (366nm) left, emission spectra under excitation at 350nm middle and chromaticity coordination diagram of BaWO4:Dy3+ material.

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  • IPEN-DOC 27635

    FERREIRA, A.H. ; MARQUES, F.N.; SOUZA, L.E. de; VARCA, G.H. ; REAL, C.C.; FARIA, D.d.; JUNQUEIRA, M.d.; LUGAO, A.B. ; FREITAS, L.F. . Radiolabeled protein nanoparticles for cancer diagnosis. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Recent advances in nanomedicine and nanotechnology have expanded the development of multifunctional nanostructures which combine specificity, diagnostic and therapeutic functions in nanostructured complexes in order to overcome biological barriers that may hinder the selective and effective administration and uptake of drugs and diagnostic agents in tumor tissue. Nanoparticles have been used in nuclear medicine as nano-radiopharmaceuticals to carry PET and SPECT ?- and ?-emitting radioisotopes used in endoradiotherapy to specifically destroy tumor tissue. The aim of the present work was the study of radiolabeling of albumin (BSA-NPs) and papain (P-NPs) nanoparticles synthesized by gamma irradiation, with 99mTc and characterize their in vitro and in vivo properties as potential novel nano-radiopharmaceuticals. Electron microscopy and light scattering techniques show spherical shapes of nanoparticles and average diameter of 9.3 ± 1.9 nm for P-NPs and 25.1 ± 2.9 nm for BSA-NPs. The radiolabeling reached around 90% yield, and the 99mTc-BSA-NPs showed stability for 24 h in all assayed conditions, while 99mTc-P-NPs presented stability for 6 h in human serum. The biodistribution studies in healthy animals have shown different excretion profiles, 99mTc-P-NPs featured a renal excretion. On the other hand the 99mTc-BSA-NPs were found in the liver and spleen to a larger extent, undergoing hepatic excretion. In vitro studies showed promising internalization rates for both nanoparticles with 74% and 57.6% of total uptake in MDA-MB231 cells, respectively for 99mTc-P-NPs and 99mTc-BSA-NPs. In vivo studies in micro-SPECT/CT images also showed a high tumor uptake for both nanoparticles. The autoradiographic studies and immunohistochemistry assays revealed a high density of both papain and BSA nanoparticles in peripheral regions of tumor tissue and confirmed the efficacy of the developed nano-radioparmaceuticals for targeting breast cancer.

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  • IPEN-DOC 27634

    NOGUEIRA, B.R. ; SOUZA, C.D. ; CARVALHO, D.V. ; ROSTELATO, M.E. ; ROSERO, W.A. . A comparison of different coatings agents for gold nanoparticles obtained with a one-pot reaction with ascorbic acid. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: The materials at nanometric size sometimes present different characteristics when compared to the same material in macrometric scale. The gold nanoparticles (AuNPs) are an example, presenting different properties such as fluorescence, melting point, electrical conductivity, magnetic permeability, chemical reactivity, and even different color than usual. Those features are direct dependence on particle size, shape, and colloidal distribution. AuNPs have desirable attributes for medical applications such as excellent biocompatibility, low toxicity, and good optical and electronic properties. AuNPs are already widely used to carry nucleotides, antibodies, and proteins in addition to biotech applications. Spherical gold nanoparticles are mainly processed by Au3+ reduction to Au+ and Au0. With the use of a stabilizing ligand, the gold nanoparticles are capped and then further growth is avoided. In this work for each 100 mL of a 0.5 mM HAuCl4, 1 mL of 0.1 M L-Ascorbic Acid solution was added, as reduction agent, under a vigorous and constantly magnetic stirring at room temperature. Almost instantly, the reaction that was originally transparent, became black and then reddish, after continued stirring for 30 min more. Three different coating agents were used in this work (SH-PEG-NH2, Arabic Gum, and Biotin). A solution with 0.1 mM of each coating agent was prepared and then in a proportion of 1:1 they were added to the AuNPs solution and putted in an orbital shaker for 2 hours. For comparison a sample with just ultrapure water, instead of the coating agent was added. Bare AuNPs and each of the coated ones were compared by using dynamic light sizer (DLS) and UV-Vis, for size measurements; and Fourier transform Infrared spectroscopy was used to evaluate bonds between the nanoparticle surface and the coating agents. Preliminary results showed that AuNPs without any coating agent presented a total smaller size (ca. 51 nm) when compared with the (ca. 84 nm)coated ones. However UV-Vis peaks indicated that the cores of the coated AuNPs are probably smaller than the non-coated. The smaller core size may be due the addition of the coating agent stopping diffusion growth. FTIR was able to confirm the presence of the agents in the NPs surface. Further analysis such as transmission electronic microscopic should confirm these results.

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  • IPEN-DOC 27619

    SOPER, FIONA; COVEY, KRISTOFER R.; PANGALA, SUNITHA R.; BERNADINO, ANGELO; BASSO, LUANA S. ; CASSOL, HENRIQUE L.G.; FEARNSIDE, PHILIP M.; NOVOA, SIDNEY; SAWAKUCHI, HENRIQUE O.; LOVEJOY, THOMAS; MARENGO, JOSE A.; PERES, CARLOS; BERNASCONI, PAULA; NARDOTO, GABRIELA B.; NOBRE, ISMAEL; MESQUITA, RITA G.; PINTO, FLAVIA; HOFFMAN, BRUCE; FREITAS, CAROLINA; ASSIS, RAFAEL L. de; BAHL, ALEXIS A.; ELMORE, AURORA; BAILLIE, JONATHON. Carbon and beyond: interactive global change impacts on Amazon biogeochemical cycles. In: AGU FALL MEETING, December 1-17, 2020, Online. Abstract... Washington, DC, USA: American Geophysical Union, 2020.

    Abstract: The Amazon is at the center of an intensifying conversation about multiple anthropogenic impacts, both direct (e.g. land use change) and indirect (climate and hydrologic change). Thus far, research has focused primarily on the cycling and storage of carbon (C) and its implications for global climate. Missing is a holistic consideration of the interactions between these anthropogenic impacts and the full suite of climate forcing agents originating in the basin, including other greenhouse gases (methane, nitrous oxide), biogenic volatile organic compounds (BVOCs), black C, transpiration and albedo. Doing so is complicated by the very large variation in biophysical, ecological, cultural and political factors across the large area of the basin. Here, we synthesize the current understanding of 1) the nature, extent, rates and drivers of all major anthropogenic changes, and 2) their expected magnitude and direction of effect on each major climate forcing agent. Studied anthropogenic impacts span a range of scales and include deforestation, agricultural conversion, hydrologic and climatic regime change, reservoir construction, fire, mining/oil extraction, hunting, severe storms and others. We identify key knowledge gaps and identify likely impacts on the net climate forcing effect of the region. We conclude that the current net positive radiative forcing of non-CO2 agents in the Amazon (in particular methane, nitrous oxide and black C) is likely be equal to or greater than the more often considered CO2 climate impact. If unchecked, the majority of anthropogenic change agents are likely to further increase net radiative forcing from the region, both by reducing C uptake and increasing emission of other agents. Most significant rate and response uncertainties are associated with 1) methane production in seasonally inundated areas and effects of temperature/hydrologic change 2) patterns and radiative forcing impacts of BVOCs, 3) impacts of spatially/temporally variable phenomena such as severe storms and 4) biogeochemical and ecological resiliency of freshwater systems. Given the large contribution of these less-recognized forcing agents, a continuing focus on a single metric of climate service is incompatible with understanding and managing the biogeochemistry of climate in a rapidly changing Amazon.

    Palavras-Chave: carbon; carbon oxides; environment; climatic change; greenhouse effect; amazon river; environmental degradation; environmental impacts; methane

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  • IPEN-DOC 27618

    BASSO, LUANA S.; GATTI, LUCIANA V.; MARANI, LUCIANO; CASSOL, HENRIQUE L.G.; TEJADA, GRACIELA; CORREA, SERGIO M.; MILLER, JOHN B.; GLOOR, MANUEL; DOMINGUES, LUCAS G.; ARAI, EGIDIO; SANCHEZ, ALBER; ARAGÃO, LUIZ E.O.C.; CORREIA, CAIO S. de C. ; NEVES, RAIANE A.L.; CRISPIM, STEPHANE P.. First Amazon Methane budget based in atmospheric long term data provided by aircraft vertical profiles measurements. In: AGU FALL MEETING, December 1-17, 2020, Online. Abstract... Washington, DC, USA: American Geophysical Union, 2020.

    Abstract: The overall Methane (CH4) budget remains highly uncertain even with the efforts to improve the estimates and contributions of its many sources (natural and anthropogenic) and few sinks. Wetland emissions are considered the primary natural CH4 source but with large uncertainty in estimations. Tropical regions like the Amazon, host some of the largest wetlands areas on the globe. However, these regions are still poorly observed with large-scale integrating observations. Here we present the first long term (2010-2018) atmospheric sampling of the lower troposphere over the Amazon using regular vertical profile (300m to 4.4km height) observations of CH4 and carbon monoxide (CO) at four sites. The sampling was nearly biweekly using small aircrafts, to provide solid seasonal and annual CH4 budgets with large spatial resolution. Was calculated a CO/CH4 ratio to estimate CH4 emissions from biomass burning. An increase in emissions mainly during the dry season at all sites from biomass burning was observed. The results show a regional variation in biogenic CH4 emissions (total minus biomass burning emissions). There are comparably high emissions from the Amazon northeast region (SAN) exhibiting strong seasonality, with particularly high CH4 fluxes one month before (February/March) the wet season peak. The second period of high emissions occurs during the beginning of the dry season (August). In the other three sites (ALF, RBA and TAB_TEF) located further downwind along the main air-stream, it were observed lower emissions, which represents approximately 20-33 % of what was observed in the northeast region and with a clear annual seasonality. Besides, we discuss how these data vary throughout the years and how it can be correlated to climate variables (temperature, precipitation and equivalent water thickness) and with human-driven influence (biomass burning), which both could be impacting this variability and annual seasonality.

    Palavras-Chave: methane; carbon monoxide; biomass; wetlands; amazon river; aircraft; troposphere; environmental impacts

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  • IPEN-DOC 27617

    GATTI, LUCIANA V.; BASSO, LUANA S.; DOMINGUES, LUCAS G.; CASSOL, HENRIQUE L.G.; TEJADA, GRACIELA; MILLER, JOHN B.; GLOOR, EMANUEL U.; ARAGÃO, LUIZ E.O.C.; NOBRE, CARLOS; PETERS, WOUTER; ANDERSON, LIANA O.; VON RANDOW, CELSO; ARAI, EGIDIO; MARANI, LUCIANO; SANCHEZ, ALBER; CORREA, SERGIO M.; CORREIA, CAIO S. de C. ; CRISPIM, STEPHANE P.; NEVES, RAIANE A.L.. Amazon plays an important climatic role and deforestation is promoting important changes and a consequent increase in the carbon balance. In: AGU FALL MEETING, December 1-17, 2020, Online. Abstract... Washington, DC, USA: American Geophysical Union, 2020.

    Abstract: We present a nine-year study designed to present both regional and temporal representation of Amazon Carbon Balance from 2010 to 2018 using 590 aircraft vertical profiles. Four locations were strategically chosen: the northeast (SAN), southeast (ALF), northwest (TAB_TEF), and southwest (RBA) regions. Each of these regions represents a different deforestation scenario, land-use change, and climate impact. For instance, 37% of the region of influence at SAN site has already deforested; it also has shown the greatest changes in precipitation and Carbon emission. The changes in precipitation (P) and temperature (T) are mainly in the dry season for all sites. At the ALF site, 28% deforested, showed the greatest changes in temperature, and the second-highest carbon emission. On the other hand, the western Amazon sites (RBA and TAB_TEF), accounted for an average of deforestation of 16%, presented near neutral carbon balance and lower changes in precipitation and temperature. The eastern Amazon (SAN + ALF) represented 22% of the Amazon area, presented 27% of deforestation and was the region where dry season presented more substantial changes in precipitation (reduced by 24-34%) and temperature (increased by 1.9-2.5 ˚C). As a consequence of these climatic and anthropic changes, the carbon flux emission at eastern Amazon was around ten times higher than at western Amazon (RBA + TAB_TEF). Eastern Amazon was a carbon source during the 9-year analysis, of which 89% of the carbon flux comes from biomass burning. In the western Amazon, the low deforestation (~11%) showed less changes in dry season P and T and carbon sink in the Net Biome Exchange (NBE C Flux: Total C Flux less Fire C Flux). If the whole Amazon had the western NBE C flux, it could be removed from the atmosphere 0.74 Gt CO2 y-1. Therefore, Amazon is becoming a carbon source mainly due the fire emissions, which represent two times the Amazon carbon sink, as a result of anthropic and climatic changes.

    Palavras-Chave: carbon; deforestation; environmental degradation; climatic change; carbon oxides; amazon river; environmental impacts

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  • IPEN-DOC 27608

    ZAHN, GUILHERME S. ; GENEZINI, FREDERICO A. ; MORALLES, MAURICIO ; SOUZA, FRANCISCO A. . Playing with neutrons: experimental facilities at the IEA-R1 reactor. In: REUNIÃO DE TRABALHO SOBRE FÍSICA NUCLEAR NO BRASIL, 43., 14-16 de dezembro, 2020, Online. Resumo... São Paulo, SP: Sociedade Brasileira de Física, 2020.

    Abstract: Due to their unique characteristics, neutrons are an excellent tool to probe materials, as well as to produce radionuclides for other uses. The IEA-R1, the largest nuclear research reactor in Brasil, located in IPEN-CNEN/SP, is a 5MW pool-type reactor from the mid-1950's that, despite its age, still provides important facilities for neutron irradiation and probing under high neutron uxes. These facilities can be divided in two groups: in-core irradiation positions with uxes ranging from 10(12) to 10(14)cm(-2).s(-1), where a sample is irradiated inside the reactor core for posterior analysis; and in-beam facilities, with 8 radial and 2 tangential tubes delivering collimated neutrons in the experimental hall with uxes up to 10(8)cm(-2).s(-1), where a sample is irradiated outide the core, under a considerably lower ux, but with the possibility of real-time analysis and of better radiation filtering and collimation. Different experiments can be performed using the IEA-R1 neutron sources, and this work intends to showcase these facilities, giving an insight regarding the specific properties or each, with their capabilities and some present applications, while also discussing some possible future applications.

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  • IPEN-DOC 27607

    SERRA FILHO, L.A.; BREGANT, M.; MUNHOZ, M.G.; SOUZA, F.A. ; MORALLES, M. . Position sensitive GEM-based neutron detector prototype. In: REUNIÃO DE TRABALHO SOBRE FÍSICA NUCLEAR NO BRASIL, 43., 14-16 de dezembro, 2020, Online. Resumo... São Paulo, SP: Sociedade Brasileira de Física, 2020.

    Abstract: In response to the 3He shortage [1], alternatives for thermal neutron detection are being pursued nowadays. Elements such as 157Gd, 10B and 6Li are commonly used to substitute 3He due to their high neutron capture cross section. In this work, we present our thermal neutron detector prototype, which makes use of 10B as converter. This detector works under Ar/CO2 (90/10) open flux and uses two gas electron multipliers (GEMs) [2] microstructures to multiply the charge signal. The neutrons are detected through the gas ionization generated by the products of the 10B(n; a)7Li reaction. The neutron capture takes place in the inside face of the aluminum cathode, which is coated with a 2:2 μm thick 10B4C layer (deposition kindly provided by the European Spallation Source (ESS) laboratories). Experimental measurements obtained in the IEA-R1 nuclear research reactor, at the Nuclear and Energy Research Institute (IPEN), shown that our prototype presents high stability, position sensitivity with spatial resolution better than 3mm and an efficiency of 2.97(25)%, allowing its application as beam profiler. Methods to increase the neutron detection efficiency will then be discussed.

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  • IPEN-DOC 27606

    SANTOS, R.F.; MUNHOZ, M.G.; MORALLES, M. . Performance and optimization simulations of a GEM-based neutron detector. In: REUNIÃO DE TRABALHO SOBRE FÍSICA NUCLEAR NO BRASIL, 43., 14-16 de dezembro, 2020, Online. Resumo... São Paulo, SP: Sociedade Brasileira de Física, 2020.

    Abstract: In this study, we are investigating the performance and optimization of a GEM-based detector to measure thermal neutrons from a nuclear reactor by means of computer simulation, using Geant4 and Garfield++. Due to the shortage of helium isotope, widely used in neutron gaseous detectors, alternatives need to be studied to continue producing this kind of detectors. The GEM detectors are a type of Micro-Pattern Gaseous Detectors (MPGD), widely used in particle tracking systems, as the Time Projection Chamber of the ALICE experiment in the LHC-CERN, and proposed for many other applications, including neutron detection. The detection of neutrons occurs through a nuclear reaction, where the products are energetic charged particles. In our application, we are using 10B as a neutron converter to induce the nuclear reaction 10B(n; )7Li. Monte Carlo simulations play an important step in the development and optimization of this kind of detectors. We are using a combination of simulation tools. At first, Geant4 is used to calculate the interaction between neutrons and the boron converter layer, as well as the transport of its products inside the converter. Then the interaction of the reaction products with the gas volume, leading to ionization or excitation of atoms, is done in Garfield++. This allows us to study the GEM in various conditions and with a detailed description of electron avalanche through the gas and its induced signals in order to achieve a tool to obtain optimized detector configurations for different applications, as beam monitors.

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  • IPEN-DOC 27605

    MEDINA, NILBERTO H.; GUAZZELLI, MARCILEI A.; AGUIAR, VITOR A.P.; LO PRESTI, DOMENICO; ADDED, NEMITALA; MACCHIONE, EDUARDO L.A.; OLIVEIRA, JOSE R.B.; MORALLES, MAURICIO ; SIQUEIRA, PAULO de T.D. ; ZAHN, GUILHERME ; GENEZINI, FREDERICO ; BONANNO, DANILO; GALLO, GIUSEPPE; RUSSO, SALVATORE; SGOUROS, ONOUFRIOS; MUOIO, ANNAMARIA; PANDOLA, LUCIANO; CAPPUZZELLO, FRANCESCO. Neutron radiation effects on the NUMEN electronic 'System On Module'. In: REUNIÃO DE TRABALHO SOBRE FÍSICA NUCLEAR NO BRASIL, 43., 14-16 de dezembro, 2020, Online. Resumo... São Paulo, SP: Sociedade Brasileira de Física, 2020.

    Abstract: The NUMEN (NUclear Matrix Elements for Neutrinoless double beta decay) project was recently proposed [1], with the aim to investigate the nuclear response to Double Charge Exchange (DCE) reactions for all the isotopes explored by present and future studies of 0νββ decay. The expected level of radiation in the NUMEN experiment imposes severe limitations on the average lifetime of the electronic devices. During the experiments it is expected that the electronic devices are exposed to about 105 neutrons/cm2/s according to FLUKA simulations. This work investigates the reliability of the System On Module (SOM) by National Instruments (NI) under neutron radiation [2]. The tests were performed using thermal, epithermal, and fast neutrons produced by the Instituto de Pesquisas Energéticas e Nucleares (IPEN) 4.5 MW Nuclear Research Reactor. The results show the NI-SOM is robust to neutron radiation for the proposed applications in the NUMEN project.

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  • IPEN-DOC 27554

    KUCHAR, NIELSEN G. ; ZAMATARO, CLAUDIA B. ; ZANINI, NATHALIA ; RABELO, THAIS F. ; JUVINO, AMANDA C. ; SOGLIA, VICTOR ; CASTRO, PEDRO A.A. ; ZEZELL, DENISE . Comportamento da hidroxiapatita do esmalte e da dentina frente à radiação ionizante in vivo e in vitro. In: CONGRESSO UNIVERSITÁRIO BRASILEIRO DE ODONTOLOGIA, 43., 18-20 de setembro, 2019, São Paulo, SP. Resumo expandido... 2019.

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  • IPEN-DOC 27551

    GATTI, LUCIANA V. ; DOMINGUES, LUCAS ; ARAGAO, LUIZ; MILLER, JOHN; BASSO, LUANA; MARANI, LUCIANO; TEJADA, GRACIELA; CASSOL, HENRIQUE; CORREIA, CAIO ; IPIA, ALBER; ANDERSON, LIANA; RANDOW, CELSO V.; GLOOR, MANUEL; PETERS, WOUTER; LOPES, RAIANE; SANTOS, RICARDO ; CRISPIM, STEPHANE. Variação Interanual do Balanço de Gases de Efeito Estufa na Bacia Amazônica e seus controles em um mundo sob aquecimento e mudanças climáticas. In: REUNIÃO ANUAL DO PROGRAMA FAPESP DE PESQUISA SOBRE MUDANÇAS CLIMÁTICAS GLOBAIS, 20-21 de fevereiro, 2019, São Paulo, SP. Poster... 2019.

    Abstract: Ao longo dos últimos 40-­‐50 anos a Amazônia vem sofrendo muitas alterações devido ao desmatamento, queima da biomassa, mudança do uso da terra, expansão urbana, malha viária, construção de hidrelétricas, exploração de mineração, petróleo e gás, etc. Esta alteração na Floresta Amazônica vem promovendo o aumento da temperatura nesta região acima do esperado e intensificação da estação seca. Estas alterações, além das alterações climáticas vem causando impacto no Balanço de Carbono da Bacia Amazônica.

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  • IPEN-DOC 27548

    YAMAGATA, CHIEKO ; MORAIS, VINICIUS R. ; MELLO-CASTANHO, SONIA R.H. . New sol-gel method for synthesis of Dy-doped yttrium disilicate phosphor not from TEOS but sodium silicate solution. In: PACIFIC RIM CONFERENCE OF CERAMIC SOCIETIES, 13th, October 27 - November 1, 2019, Okinawa, Japan. Abstract... 2019.

    Abstract: Yttrium disilicate/pyrosilicate (Y2Si2O7), which occurs naturally as yttrialite, is a mixture of rare earth silicates that displays interesting structural properties because of its high refractoriness (mp = 1775 °C) and stability in oxidizing environments. Yttrium disilicate offers a wide band gap and excellent thermal and chemical stability compared to other well-studied phosphors such as ZnS and CdS. It has been shown to be one of the most efficient host lattices for rare earth ions, which substitute Y3+ ions [1, 2]. Yttrium silicates doped with different metallic ions exhibit attractive luminescent properties for potential applications, such as plasma displays, laser materials and high-energy phosphors [3]. The synthesis methods frequently used to obtain Y2Si2O7 are the conventional solid-state reaction, sol-gel and hydrothermal process. The sol–gel process is based on the polycondensation of hydrolyzed alkoxides or colloidal dispersions, therefore non-substituted and substituted silicon alkoxides are used as source of Si, typically Si(OC2H5)4 (TEOS) or CH3–Si(OC2H5)3 (MTEOS). In the present work, a new method to synthesize Dy-doped yttrium disilicate (Dy0,05Y1,95Si2O7) phosphors is proposed using a combination of sol-gel and coprecipitation techniques. The gel of silica particles were obtained by surfactant-assisted sol-gel process [4], from sodium silicate solution, an unusual precursor of Si. Then yttrium and dysprosium were co-precipitated over these particles. Pure α-phase and β-phase of Y2Si2O7 were obtained after calcining the synthesized precursor at 1100°C and 1400°C respectively (Fig. 1). β-phase showed superior luminescence efficiency (Fig. 2).

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  • IPEN-DOC 27547

    YAMAGATA, CHIEKO ; LEME, DANIEL R. ; RODAS, ANDREA C.D.; HIGA, OLGA Z. ; MELLO-CASTANHO, SONIA R.H. . Use of sodium silicate waste solution as Si source to synthesize MgO-CaO-SiO2 system ceramic powder for biomedical application. In: PACIFIC RIM CONFERENCE OF CERAMIC SOCIETIES, 13th, October 27 - November 1, 2019, Okinawa, Japan. Abstract... 2019.

    Abstract: The superior biological and mechanical properties of the glass ceramic of MgO-CaO-SiO2 system [1], for fabricating bone scaffolds, have attracted considerable attention. Studies showed that glass-ceramic with the composition Wt% 7.68 MgO, 43.19 CaO and 49.13 SiO2 displays appropriate mechanical properties, good bioactivity and biocompatibility in vitro [2]. The aim of this research was to propose a novel method of synthesis of MgO-CaO-SiO2 system ceramic powder. Using a waste solution of sodium silicate derived from alkaline fusion process of zircon sand, as source of Si, MgO-CaO-SiO2 system ceramic powder was synthesized by sol-gel added to co-precipitate of Mg and Ca hydroxides. Present synthesized powder was compacted and sintered at 1300 °C for 2h to obtain CaO-MgO-SiO2 glass-ceramic that was characterized by SEM, XRD and FTIR. In vitro tests were performed by soaking the sintered samples in the simulate blood fluid (SBF, at pH 7.25 and 37 °C) to study its bioactivity. After 7 days soaking, FTIR spectra (Fig. 1) result showed the material is bioactive, confirmed by presence of infrared band at 1047 cm-1 attributed to PO43- and observation of hydroxyapatite coating on the surface of the sample (Fig. 2). Cytotocicity test according to ISO10993-5 and sample preparation according to ISO10993-12 revealed that the sample is considered non-cytotoxic and it can be eligible for further biological testes.

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  • IPEN-DOC 27537

    OSTERMANN, CAROLINE ; ZANNONI, NORA; CARVALHO, ELIAS F. de ; WILLIAMS, JONATHAN; VEGA, OSCAR . Exploratory study on chiral BVOC fluxes from tropical forests by REA method. In: ATTO WORKSHOP, 3rd, September 16-20, 2019, Manaus, AM. Poster... 2019.

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  • IPEN-DOC 27469

    RUSSO, DANIELA C.; AMARAL, KLEICY C. ; CALDAS, LHAIS A.; VIEIRA, DANIEL P. ; SARTORELLI, PATRICIA; RIBEIRO FILHO, WALDEMAR A.. Cytotoxic activity and chemical profile of methanolic extract obtained from Avelós stem (Euphorbia tirucalli L.) Euphorbiaceae / Atividade citotóxica e perfil químico do extrato metanólico obtido do caule de Avelós (Euphorbia tirucalli L.) Euphorbiaceae. In: REUNIÃO ANUAL VIRTUAL DA SBQ, 43., 5-16 de outubro, 2020, Virtual. Resumo... Campinas: Galoá, 2020.

    Abstract: Avelós (Euphorbia tirucalli Linnaeus), a plant selected for this study, has been popularly used in the fight against tumors, arousing the interest of researchers in this area so that it can be used safely in the auxiliary treatment of different types of cancer.1 It belongs to the family Euphorbiaceae and to the genus Euphorbia, it is also the object of studies related to the treatment of a range of infectious and inflammatory diseases. Herbaceous much used by popular and traditional medicine, presents, a latex rich in molecules that confirm its high toxicity. The objective of this research was to verify the chemical profile of the metanolic extract obtained from the stem (modified leaves) of the plant in question and to determine the cytotoxicity of the crude extract by cytotoxic assay against the lineages of adenocarcinoma (MCF-7) and neoplastic cells of human melanoma (SK-MEL-37).2 For this, the plant was collected, and after drying and milling the material was extracted with methanol. Subsequently, the present compounds were separated by the thin-layer chromatography technique and the classes of substances found in the extract were identified by the technique of Nuclear Magnetic Resonance of Hydrogen and Carbon-13 (NMR).3 The combination of cyclohexane with Acetone and Hexane (5: 3: 2) provided a suitable polarity for the elution of the extract, which was revealed with ultraviolet detection and different reagents: sulfuric acid solutions; aluminum chloride; ferric chloride; 10% potassium hydroxide in ethanol; green bromocresol indicator solution; potassium permanganate, Dragendorff Reagent, vanillin and iodine vapors. The phytochemical study of the methanolic extract of Euphorbia tirucalli allowed to identify the presence of phenolic compounds, flavonoids and terpenes, a result that was confirmed by NMR spectra. The cytotoxic potential assays, although they are in low concentration thus altering the result, show that the methanolic extract of Euphorbia tirucalli shows activity against the tested cell lines. The observed activity may be related, according to information available in the literature, with the classes identified in the samples studied.

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A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

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O Repositório Digital do IPEN é um equipamento institucional de acesso aberto, criado com o objetivo de reunir, preservar, disponibilizar e conferir maior visibilidade à Produção Científica publicada pelo Instituto, desde sua criação em 1956.

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A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.