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  • IPEN-DOC 27303

    CAETANO, GABRIELA A.; LUZ, TEMISTOCLES de S.; COELHO, LUCAS M.; ROSSI, JESUALDO L. ; ORLANDO, MARCOS T.D.. Efeito de tratamentos térmicos nas propriedades mecânicas de chapas soldadas do aço inoxidável duplex UNS S32304 / Effect of heat treatments on the mechanical properties in UNS S32304 duplex stainless steel welded plates. Tecnologia em Metalurgia, Materiais e Mineração, v. 16, Especial, 2019. DOI: 10.4322/2176-1523.20191931

    Abstract: O aço inoxidável duplex UNS S32304 tem sido investigado como candidato para construção de um receptáculo para transporte de material radioativo associado ao futuro Reator Multipropósito Brasileiro (RMB). O foco deste trabalho é avaliar o efeito de diferentes temperaturas de tratamento térmico em chapas de UNS S32304 com espessura de 1,8mm após processo de soldagem TIG autógeno. Utilizou-se corrente pulsada com polaridade direta, gás de proteção com uma mistura de argônio e 2% de nitrogênio e um sistema de acionamento automático com controle digital dos parâmetros. Os corpos de prova soldados e como recebido foram tratados termicamente durante 8h a temperaturas de 475, 600 e 750°C seguido de resfriamento ao ar. As amostras foram submetidas a ensaios de tração com taxa de deformação de 10-4s-1. Comprovou-se que somente a amostra tratada a 600°C mostrou um comportamento tensão-deformação similar à amostra como recebida. Para as amostras soldadas, o tratamento a 600°C aumentou o limite de resistência à tração e o alongamento % total em relação à amostra somente soldada e sem tratamento térmico.

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  • IPEN-DOC 26680

    ESTRADA-VILLEGAS, G.M.; MORSELLI, G. ; OLIVEIRA, M.J.A. ; GONZALEZ-PEREZ, G. ; LUGAO, A.B. . PVGA/Alginate-AgNPs hydrogel as absorbent biomaterial and its soil biodegradation behavior. Polymer Bulletin, v. 77, n. 8, p. 4147-4166, 2020. DOI: 10.1007/s00289-019-02966-x

    Abstract: PVGA, silver nitrate ( AgNO3) and alginate (Alg) were cross-linked by using γ-ray radiation to obtain Alg/PVGA/AgNPs as a potential biomaterial. The hydrogel composition was characterized by several analytics methods, and the morphology was evaluated by scanning electron microscopy. The swelling behavior was tested in different mediums. The stability of AgNPs was followed by UV–Vis at 400 nm for 1 month. The hydrogel soil biodegradation was analyzed by visual observation, weight loss, Fourier transform infrared spectroscopy and thermogravimetric analysis for 120 days. A simple biodegradation mechanism has been proposed based on results. Additionally, cytotoxicity assays were carried out using NCTC 929 cells to observe cell viability.

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  • IPEN-DOC 26565

    NOGUEIRA, ANDRE L.; MUNITA, CASIMIRO S. . Quantitative methods of standardization in cluster analysis: finding groups in data. Journal of Radioanalytical and Nuclear Chemistry, v. 325, n. 3, p. 719-724, 2020. DOI: 10.1007/s10967-020-07186-6

    Abstract: The aim of this paper is to evaluate the impact of three standardization methods (z-score, log10 and improved min–max) in determining the number of clusters for a dataset of 146 archaeological ceramic fragments in which mass fractions of chemical elements were determined by INAA. The results showed a tendency towards clustering, which did not occur to the non-standardized data. The standardization methods indicated the presence of three groups within the database. Quality evaluation of these clusters, by means of internal validation indexes, showed that the best performance was obtained with the log10 transformation. This transformation also performed well in the calculation of compactness, while the improved min–max showed better performance in terms of separability.

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  • IPEN-DOC 27255

    LO PRESTI, DOMENICO; MEDINA, NILBERTO H.; GUAZZELLI, MARCILEI A.; MORALLES, MAURICIO ; AGUIAR, VITOR A.P.; OLIVEIRA, JOSE R.B.; ADDED, NEMITALA; MACCHIONE, EDUARDO L.A.; 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 an electronic system on module. Review of Scientific Instruments, v. 91, n. 8, p. 083301-1 - 083301-5, 2020. DOI: 10.1063/5.0010968

    Abstract: The NUMEN (NUclear Matrix Elements for Neutrinoless double beta decay) project was recently proposed with the aim to investigate the nuclear response to Double Charge Exchange 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 will be exposed to about 105 neutrons/cm2/s according to FLUKA simulations. This paper investigates the reliability of a System On Module (SOM) under neutron radiation. The tests were performed using thermal, epithermal, and fast neutrons produced by the Instituto de Pesquisas Energéticas e Nucleares 4.5MWNuclear Research Reactor. The results show that the National Instruments SOM is robust to neutron radiation for the proposed applications in the NUMEN project.

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  • IPEN-DOC 27254

    SARKAR, CHINMOY; GUENTHER, ALEX B.; PARK, JEONG-HOO; SECO, ROGER; ALVES, ELIANE; BATALHA, SARAH; SANTANA, RAONI; KIM, SAEWUNG; SMITH, JAMES; TOTA, JULIO; VEGA, OSCAR . PTR-TOF-MS eddy covariance measurements of isoprene and monoterpene fluxes from an eastern Amazonian rainforest. Atmospheric Chemistry and Physics, v. 20, n. 12, p. 7179-7191, 2020. DOI: 10.5194/acp-20-7179-2020

    Abstract: Biogenic volatile organic compounds (BVOCs) are important components of the atmosphere due to their contribution to atmospheric chemistry and biogeochemical cycles. Tropical forests are the largest source of the dominant BVOC emissions (e.g. isoprene and monoterpenes). In this study, we report isoprene and total monoterpene flux measurements with a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) using the eddy covariance (EC) method at the Tapajós National Forest (2.857∘ S, 54.959∘ W), a primary rainforest in eastern Amazonia. Measurements were carried out from 1 to 16 June 2014, during the wet-to-dry transition season. During the measurement period, the measured daytime (06:00–18:00 LT) average isoprene mixing ratios and fluxes were 1.15±0.60 ppb and 0.55±0.71 mg C m−2 h−1, respectively, whereas the measured daytime average total monoterpene mixing ratios and fluxes were 0.14±0.10 ppb and 0.20±0.25 mg C m−2 h−1, respectively. Midday (10:00–14:00 LT) average isoprene and total monoterpene mixing ratios were 1.70±0.49 and 0.24±0.05 ppb, respectively, whereas midday average isoprene and monoterpene fluxes were 1.24±0.68 and 0.46±0.22 mg C m−2 h−1, respectively. Isoprene and total monoterpene emissions in Tapajós were correlated with ambient temperature and solar radiation. Significant correlation with sensible heat flux, SHF (r2=0.77), was also observed. Measured isoprene and monoterpene fluxes were strongly correlated with each other (r2=0.93). The MEGAN2.1 (Model of Emissions of Gases and Aerosols from Nature version 2.1) model could simulate most of the observed diurnal variations (r2=0.7 to 0.8) but declined a little later in the evening for both isoprene and total monoterpene fluxes. The results also demonstrate the importance of site-specific vegetation emission factors (EFs) for accurately simulating BVOC fluxes in regional and global BVOC emission models.

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  • IPEN-DOC 27253

    LANDULFO, EDUARDO ; VEGA, ALBEHT R.; YOSHIDA, ALEXANDRE C. ; BASTIDAS, ALVARO; SANTOS, AMANDA V. dos; SILVA, ANTONIETA; GOMES, ANTONIO A. ; GONZALEZ, BORIS B.; MELO-LUNA, CARLOS A.; HOYOS, CARLOS D.; RAE, CRISTINA T. de S.; CAMILO, DANIEL; VIVAS, DAVID; GOUVEIA, DIEGO A.; WOLFRAM, ELIAN; COLLINI, ESTELA; LOPES, FABIO J.S. ; MOREIRA, GREGORI de A. ; BARBOSA, HENRIQUE de M.J.; CIMINARI, HERNAN; REINA, JOHN H.; SILVA, JONATAN J. da ; CESPEDES, JONNATHAN; MARRERO, JUAN C.A.; RASCADO, JUAN L.G.; PALLOTTA, JUAN; HOELZEMANN, JUDITH; ARBOLEDAS, LUCAS A.; SALLES, M.ALEJANDRA; SILVA, MARCOS P.A. da; SAMMARA, RENATA; FORNO, RICARDO N.; PAPANDREA, SEBASTIAN. LALINET network status. EPJ Web Conferences, v. 237, p. 1-4, 2020. DOI: 10.1051/epjconf/202023705008

    Abstract: LALINET (Latin American Lidar Network) follows its goal to consolidation as a federative lidar network to provide regional coverage over Latin America in providing aerosol and greenhouse gas profiles following QA/QC protocols and promoting the development of researchers and students in atmopheric science field. We show recent results on different approaches for studying the optical properties of the atmosphere regarding aerosols at tropospheric and stratospheric level and greenhouse gas mixing ratio profiles followed by our recent support and validation efforts towards present and future satellite missions.

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  • IPEN-DOC 27252

    ROVANI, SUZIMARA ; SANTOS, JONNATAN J.; GUILHEN, SABINE N. ; CORIO, PAOLA; FUNGARO, DENISE A. . Fast, efficient and clean adsorption of bisphenol-A using renewable mesoporous silica nanoparticles from sugarcane waste ash. RSC Advances, v. 10, n. 46, p. 27706–27712, 2020. DOI: 10.1039/d0ra05198e

    Abstract: Even with all the biological problems associated with bisphenol-A (BPA), this chemical is still being widely used, especially in thermal paper receipts. In this study, renewable mesoporous silica nanoparticles (MSN), obtained from sugarcane ash, functionalized with hexadecyltrimethylammonium (CTAB) were applied as an adsorbent in the removal of BPA from the aqueous solution. The versatility of this material and its BPA adsorption capacity were tested at different pH values, being practically constant at pH between 4 and 9, with a slight increase in pH 10 and a greater increase in pH 11. The removal time evaluation indicates a very fast adsorption process, removing almost 90% of BPA in the first 20 min of contact. The kinetic model indicates a monolayer formation of BPA molecules on the MSN-CTAB surface. The maximum adsorption capacity (Qmax) was 155.78 mg g-1, one of the highest found in literature, and the highest for material from a renewable source.

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  • IPEN-DOC 27251

    SILVA, JONATAN da ; MORAIS, FERNANDO G. ; FRANCO, MARCO A.; LOPES, FABIO J.S. ; ARRUDA, GREGORI de A. ; YOSHIDA, ALEXANDRE C. ; CORREIA, ALEXANDRE; LANDULFO, EDUARDO . Exploring the twilight zone: a multi-sensor approach. EPJ Web Conferences, v. 237, p. 1-4, 2020. DOI: 10.1051/epjconf/202023707015

    Abstract: This study shows a set of analysis of measurements from ground-based and satellite instruments to characterize the twilight zone (TLZ) between clouds and aerosols in São Paulo, Brazil. In the vicinity of clouds turbulence measurements showed an intense upward movement of aerosol layers, while sunphotometer results showed an increase in aerosol optical depth, and lidar measurements showed an increase in the backscatter vertical profile signal.

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  • IPEN-DOC 27250

    MEDEIROS, VINICIUS L.; ARAUJO, LEANDRO G. de ; RATERO, DAVI R.; PAULA, ALEX S.; MOLINA, EDUARDO F.; JAEGER, CHRISTIAN; MARUMO, JULIO T. ; NERY, JOSE G.. Synthesis and physicochemical characterization of a novel adsorbent based on yttrium silicate: a potential material for removal of lead and cadmium from aqueous media. Journal of Environmental Chemical Engineering, v. 8, n. 4, p. 1-10, 2020. DOI: 10.1016/j.jece.2020.103922

    Abstract: A new metallosilicate based on yttrium was synthesized and characterized by XRD, FT-IR, 29Si MAS-NMR, and 89Y MAS-NMR. The mixed framework of the material was confirmed by the detection of distinct chemical shift groups using 29Si MAS-NMR (at -82 to -87 ppm, -91 to -94 ppm, -96 to -102 ppm, and -105 to -108 ppm), as well as four distinct chemical shifts in the 89Y MAS-NMR spectrum (at -89, -142, -160, and -220 ppm). Adsorption and kinetic analyses indicated the potential of the new material for the removal of lead and cadmium from aqueous media. The adsorption results for lead indicated that dynamic equilibrium was reached after five hours, with total lead removal of around 94 %, while for cadmium it was reached in the first hour, with total cadmium removal of around 74 %. The adsorptions of lead and cadmium were modeled using pseudo-first order (PFO) and pseudo-second order (PSO) kinetic models. Although both models provided high R2 values (0.9903 and 0.9980, respectively), the PSO model presented a much lower χ2 red value (4.41×10−4), compared to the PFO model (2.12×10−3), which indicated that the rate-limiting step was probably due to the chemisorption of lead from the solution onto the yttrium-based metallosilicate.

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  • IPEN-DOC 27249

    SILVA, E. ; SANTOS, L.R.; ASSEMANY, L.P.F. ; POTIENS, M.P.A. . Evaluation of the performance of radioprotection ionization chambers used in radiometric survey of clinical systems. Brazilian Journal of Radiation Sciences, v. 8, n. 1A, p. 1-10, 2020. DOI: 10.15392/bjrs.v8i1A.1076

    Abstract: The use of ionizing radiation for medical purposes was a major advancement for society due to the various possibilities of use for the treatment and diagnosis of diseases. On the other hand, knowledge about the damage caused by the biological effects of ionizing radiation requires a continuous improvement of the quality control of diagnostic radiology. Radiation detector equipment is used to measure the levels of radiation emitted by sources be they natural or artificial. For practicality and precision, among the most commonly used detectors are the ionization chambers. Especially in outdoor areas climatic factors may affect the behavior of these detectors at the time of measurement, but Brazilian legislation only recommends the calibration of these measuring instruments in a traceable laboratory every two years to ensure their reliability. The objective of this work was to evaluate the performance of an ionization chamber used in radioprotection measurements in diagnostic radiology equipment, considering the climatic variations in the different regions of Brazil. For this, a system was developed to simulate the environmental conditions found for the parameters of temperature and humidity at the time of clinical measurements, making it possible to estimate the influence of these factors on the values obtained.

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  • IPEN-DOC 27248

    LIMA, B.L.; ALMEIDA, J.S. ; POTIENS, M.P.A. ; PELISSONI, R.A.; SAPIENZA, M.T.; BUCHPIGUEL, C.A.; WILLEGAIGNON, J.. Evaluation of biokinetics and dosimetry in [131I]-NaI therapies: quantification of whole body images versus thigh region. Brazilian Journal of Radiation Sciences, v. 8, n. 1A, p. 1-13, 2020. DOI: 10.15392/bjrs.v8i1A.1082

    Abstract: This study evaluate the possibility of restricting the current image quantification (ROI) from the whole body to a small area in thigh for therapy planning. Whole body planar images were obtained from 13 patients after the administration of 131I tracer dose, and OLINDA/EXM software was used for internal dose calculation. The average value of half-life time was 16.46 ± 3.45 h in whole body quantification, compared to 14.07 ± 2.89 h in thigh. The average absorbed dose in bone marrow from the whole body quantification was 0.0519 ± 0.0250 mGy/MBq, whilst the absorbed dose provided by the thigh quantification represented 87% of this value, with up to 95% in time reduction for dose calculation. Such doses become similar when a correction factor of 1.13 is applied in thigh dose results (p=0.67), which is within the variation coefficient assumed to internal dosimetry (20%). This study shows the possibility of a significant time reduction in internal dose calculation applied to therapy planning.

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  • IPEN-DOC 27247

    VARCA, JUSTINE P.R.O. ; MARTINS, ELAINE A.J. ; VARCA, GUSTAVO H.C. ; ROMANO, RENATO L.; LEBRE, DANIEL T.; LAINETTI, PAULO E.O. ; BUSTILLOS, JOSE O.V. . Determination of organochlorines in soil of a suburban area of São Paulo Brazil. International Journal of Environmental Research and Public Health, v. 17, n. 16, p. 1-16, 2020. DOI: 10.3390/ijerph17165666

    Abstract: Technological advances have promoted improvements in several science fields, especially related to environmental and analytical areas with the improvement of detection and development of environmentally friendly extraction techniques. This study applied Quick, Easy, Cheap, Effective, Rugged and Safe method (QuEChERS) for soil extraction and assessed its performance through a validation study using samples from the soil of a contaminated area in Caieiras, SP, Brazil. Nine organochlorine pesticides, including the isomers alpha, beta, gamma and delta- hexachlorocyclohexane; cis- and trans-heptachlor epoxide; cis- and trans-chlordane and heptachlor were analyzed by gas chromatography coupled to electron capture detector. The method was validated according to ISO 5725-4 (2020), EURACHEM (2014) and DOQ-CGCRE-008 (2016). The limits of detection and quantification of the method for the nine organochlorines were α-HCH (1.2 and 12.6 µg kg−1), β-HCH (1.7 and 12.0 µg kg−1), γ-HCH (1.5 and 11.6 µg kg−1), δ-HCH (0.8 and 11.6 µg kg−1), heptachlor (1.0 and 10.8 µg kg−1), cis-heptachlor epoxide (0.9 and 11.5 µg kg−1), trans-heptachlor epoxide (0.9 and 11.5 µg kg−1), cis-chlordane (0.4 and 7.9 µg kg−1) and trans-chlordane (0.5 and 10.9 µg kg−1), respectively, and all of them were within the maximum limits recommended by the EPA for the compounds α-HCH (86.0 and 360.0 µg kg−1), β-HCH (300.0 and 1.3 × 103 µg kg−1), γ-HCH (570.0 and 2.5 × 103 µg kg−1), δ-HCH (not defined), heptachlor (130.0 and 630.0 µg kg−1), cis-/trans-heptachlor epoxide (7.0 and 330.0 µg kg−1), cis-/trans-chlordane (1.77 × 103 and 7.7 × 103 µg kg−1) in residential and industrial soil, respectively. Recovery results were between 65% and 105% for almost all compounds, which is an optimum result for multi-residue analytical methods, considering the complexity of the matrix used in the study. Caieiras presented contamination levels of α-HCH in the range of 2.0 to 66.0 µg g−1, which was higher than the limits established by EPA, corresponding to 0.077 µg g−1 for residential soil and 0.27 µg g−1 for industrial soil. According to the validation study, the analytical method proposed was reliable for organochlorine quantification, and the QuEChERS was considered efficient for organochlorine extraction from soil.

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  • IPEN-DOC 27246

    GARCIA, LUIS M.S. ; RAJAK, SANIL; CHAIR, KHAOULA; GODOY, CAMILA M. ; SILVA, ARACELI J.; GOMES, PAULO V.R.; SANCHES, EDGAR A.; RAMOS, ANDREZZA S.; SOUZA, RODRIGO F.B. de ; DUONG, ADAM; NETO, ALMIR O. . Conversion of methane into methanol using the [6,6′-(2,2′-bipyridine-6,6′-diyl)bis(1,3,5-triazine-2,4-diamine)](nitrato-O)copper(II) complex in a solid electrolyte reactor fuel cell type. ACS Omega, v. 5, n. 26, p. 16003-16009, 2020. DOI: 10.1021/acsomega.0c01363

    Abstract: The application of solid electrolyte reactors for methane oxidation to co-generation of power and chemicals could be interesting, mainly with the use of materials that could come from renewable sources and abundant metals, such as the [6,6′- (2, 2′-bipyridine-6, 6′-diyl)bis (1,3,5- triazine-2, 4-diamine)](nitrate-O)copper (II) complex. In this study, we investigated the optimal ratio between this complex and carbon to obtain a stable, conductive, and functional reagent diffusion electrode. The most active Cu-complex compositions were 2.5 and 5% carbon, which were measured with higher values of open circuit and electric current, in addition to the higher methanol production with reaction rates of 1.85 mol L−1 h−1 close to the short circuit potential and 1.65 mol L−1 h−1 close to the open circuit potential, respectively. This activity was attributed to the ability of these compositions to activate water due to better distribution of the Cu complex in the carbon matrix as observed in the rotating ring disk electrode experiments.

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  • IPEN-DOC 27245

    FONTES, ERIC H. ; NANDENHA, JULIO ; PIASENTIN, RICARDO M. ; SOUZA, RODRIGO F.B. de ; NETO, ALMIR O. . Comparison of various atomic compositions of Au@Pd/C, Pd/C, and AuPd/C electrocatalysts for direct ethanol fuel cells. Energy Storage, v. 2, n. 3, p. 1-15, 2020. DOI: 10.1002/est2.139

    Abstract: Pd/C, Au@Pd/C (core-shell), and AuPd/C (AR—consisting in Au microparticles) were used as electrocatalysts for ethanol oxidation in alkaline medium. A synergistic effect between Au and Pd atoms in Au@Pd/C makes the binding between ethanol and Au@Pd/C stronger. This leads to product formation in higher potentials and can be useful to select ethanol products. We also showed that the atomic composition of the electrocatalysts to be used in fuel cells and in powder form to be used in electrochemical experiments are very similar, reaching high values of correlation. The depth profiling X-ray photoelectron spectroscopy for the anode catalysts to be used in fuel cells can provide new insights about ethanol oxidation in direct ethanol fuel cells (DEFCs), for instance, metal oxide species can act in fuel cells environment. In terms of electric generation, Au@Pd/C presented a better performance in electrochemical experiments; the current density was about 1.6 times higher than the peak current density obtained for Pd/C. In terms of electrochemical stability, Au@Pd/C presented better final current density when compared to Pd/C and AuPd/C electrocatalysts. However, in DEFC experiments, Pd/C showed better performance.

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  • IPEN-DOC 27244

    MOREIRA, GREGORI de A. ; LOPES, FABIO J. da S. ; GUERRERO-RASCADO, JUAN L.; ORTIZ-AMEZCUA, PABLO; CAZORLA, ALBERTO; OLIVEIRA, AMAURI P. de; LANDULFO, EDUARDO ; ALADOS-ARBOLEDAS, LUCAS. Comparison among the atmospheric boundary layer height estimated from three different tracers. EPJ Web Conferences, v. 237, p. 1-4, 2020. DOI: 10.1051/epjconf/202023703009

    Abstract: The Atmospheric Boundary Layer (ABL) is the lowermost part of the troposphere. In this work, we analysed the combination of ABL height estimated continuously by three different remote sensing systems: a ceilometer, a Doppler lidar and a passive Microwave Radiometer, during a summer campaign, which was held in Granada from June to August 2016. This study demonstrates as the combined utilization of remote sensing systems, based on different tracers, can provide detailed information about the height of ABL and their sublayers.

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  • IPEN-DOC 27243

    CHIERENTIN, GABRIEL de S. ; ARMELIN, MARIA J.A. ; MASTRO, NELIDA L. del . Chia trace elements detection by neutron activation analysis / Detecção de elementos traço de chia por análise de ativação neutrônica. Brazilian Journal of Development, v. 6, n. 7, p. 43049-43054, 2020. DOI: 10.34117/bjdv6n7-065

    Abstract: Chia seed is an ancient grain that is becoming popular in modern food regimen for their nutritional value and functional properties, although many tables of food composition do not provide complete information about it. Trace and ultra-trace elements are indispensable for human health as they are involved in biochemistry regulations, such as transport and oxygen activation, electron transport, catalytic center in oxide reduction processes, catalytic center in acid-base processes and structural function. For both diet assessment and prescription, reference values for trace elements as recommended daily intake, recommended dietary allowance and tolerable upper intake level were established. Instrumental neutron activation analysis (INAA) is a noble method to identify and quantify trace and ultra-trace elements that has high sensitivity for many elements, has little or no sample contamination, resulting in low blank values, has virtually no matrix effects and multi element capability. The aim of the present work was to identify and quantify by INAA mineral elements of chia seeds. The results showed higher content of Ca, K, Zn and Fe when compared with data from the literature obtained by other analytical methods. Besides that, using INAA was possible to detect elements that was not commonly verified with others measuring methods.

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  • IPEN-DOC 27242

    BORGES, EDUARDO M. ; CONTI, THADEU das N. ; SANCHES, ANDREA ; SABUNDJIAN, GAIANE . Análise do acidente de perda de refrigerante primário devido a quebra da linha de surto do pressurizador da usina nuclear Angra 2 / Loss of Coolant Accident Analysis by breaking of the pressurizer surge line of the Angra 2 nuclear power plant. Revista Internacional de Ciências, v. 10, n. 1, p. 3-21, 2020. DOI: 10.12957/ric.2020.44530

    Abstract: O objetivo deste trabalho foi simular e avaliar com o código RELAP5 o acidente base de projeto de perda de refrigerante primário devido a uma ruptura média na linha de surto do pressurizador da usina nuclear Angra 2. Este acidente foi uma quebra do tipo guilhotina ou seja 100% na linha de surto do pressurizador, que representa uma ruptura de 437 cm². Nesta análise, verificou-se que as lógicas de atuação do Sistema de Proteção do Reator (SPR) e do Sistema de Resfriamento de Emergência do Núcleo (SREN) de Angra 2, utilizadas nesta simulação, funcionaram corretamente, mantendo a integridade do núcleo com as temperaturas do núcleo em níveis aceitáveis durante todo o evento. Os resultados obtidos foram satisfatórios, quando comparados com os apresentados no Relatório Final de Análise de Segurança de Angra 2 (FSAR/A2).

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  • IPEN-DOC 27241

    SILVA FILHO, J.C.; VENANCIO, E.C.; SILVA, S.C. ; TAKIISHI, H. ; MARTINEZ, L.G. ; ANTUNES, R.A.. A thermal method for obtention of 2 to 3 reduced graphene oxide layers from graphene oxide. SN Applied Sciences, v. 2, n. 8, 2020. DOI: 10.1007/s42452-020-03241-9

    Abstract: In this work, a thermal reduction method was developed to obtain reduced graphene oxide (rGO) with 2 or 3 layers from graphene oxide (GO). The GO X-ray diffraction (XRD) patterns presented diffraction peak at 2θ = 10°, which is related to (002) reflection. After heat treatment under nitrogen ( N2(g)) atmosphere, this peak was shifted to 2θ = 25°, presenting an interlayer distance of 3.8 Å, associated to GO reduction. BET analysis of modified GO samples identified an average pore diameter of 45.38 Å and surface area of 23.06 m2/g. In the case of rGO1, rGO2 and rGO3 samples, they presented surface areas from 32.47 to 612.74 m2/g and an average pore diameter of 108.21–149.54 m2/g. Thermogravimetric analysis (TGA) indicated a higher mass loss between 150 and 230 °C. Raman spectra showed ID/IG ratios of rGO samples were higher than GO (1.36-GO; 1.45-rGO1, 1.87-rGO3) due to reducing GO and increasing sp2 clusters. XPS analysis revealed that the main carbon species in the samples were sp2- type bonds (14.99 at% for the GO and 47.85 at% for rGO3). The FTIR spectra of rGO1, rGO2 and rGO3 samples presented peaks at 3454.22 cm−1 (hydroxyl) and 1077.43 cm−1 (C–O).

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  • IPEN-DOC 27240

    SARKAR, CHINMOY; TURNIPSEED, ANDREW; SHERTZ, STEPHEN; KARL, THOMAS; POTOSNAK, MARK; BAI, JIANHUI; SERÇA, DOMINIQUE; BONAL, DAMIEN; BURBAN, BENOIT; LOPES, PAULA R.C. ; VEGA, OSCAR ; GUENTHER, ALEX B.. A portable, low-cost relaxed eddy accumulation (REA) system for quantifying ecosystem-level fluxes of volatile organics. Atmospheric Environment, v. 242, p. 1-12, 2020. DOI: 10.1016/j.atmosenv.2020.117764

    Abstract: Quantification of biogenic volatile organic compound (BVOC) fluxes into the atmosphere is crucial to understand their role in atmospheric oxidation and biogeochemical cycles. BVOC flux measurements were carried out in nine forest ecosystems using a relaxed eddy accumulation (REA) based sampling system, which is easily transportable, simple to operate and designed to be low-cost and therefore can easily be deployed at multiple remote locations. The REA measurements were carried out during daytime between 06:00 and 18:30 (Local Time) with a flux averaging period of 30 min. A detailed description of the REA sampling setup, operational procedure and validation by comparison with full eddy covariance (EC) BVOC flux measurements is provided. BVOC flux measurements from established long-term carbon and water flux tower sites in nine forest ecosystems are compared including Manitou Forest Observatory in Colorado, USA (pine woodland forest), Niwot Ridge AmeriFlux site in Colorado, USA (subalpine forest), Deer Canyon Preserve in New Mexico, USA (pinyon-juniper forest), Lei bamboo forest site near Taihuyuan, China, Qianyanzhou ChinaFLUX site in China (pine forest), Baskett Wildfire Refuge MOFlux site in Missouri, USA (deciduous oak forest), University of Michigan Biological Station PROPHET site in Michigan, USA (mixed deciduous forest), Changbai Mountain Forest Research Station in China (mixed deciduous forest) and the Guyaflux site (GF-Guy) in French Guiana (tropical rainforest). BVOC flux measurements using our REA setup confirm dominance of 2,3,2- methylbutenol (2,3,2-MBO) at the Manitou Forest Observatory and Niwot Ridge sites in Colorado. Monoterpene fluxes measured by REA showed good agreement (within ±10%) with monoterpene fluxes measured by PTR-MS at the Manitou Forest Observatory. The MOFlux site in Missouri was dominated by isoprene emissions (average flux of ~ 9.5 mg m􀀀 2 h􀀀 1) whereas the Deer Canyon site was dominated by α-pinene emissions (average flux ~ 0.73 mg m􀀀 2 h􀀀 1). Mixed deciduous forest sites at the PROPHET Station in Michigan and Changbai Mountain Forest Research Station in China primarily emitted isoprene along with some α-pinene, β-pinene and d-Limonene. Isoprene and α-pinene were the dominant BVOCs emitted from the subtropical Lei bamboo plantation at the Taihuyuan site in China while the pine forest site at Qianyanzhou in China were dominated by α-pinene emissions along with significant isoprene. BVOC measurements across different seasons (during 2009–2011) at a tropical forest site in French Guiana (Guyaflux site) revealed the dominance of isoprene emissions during all seasons. Irrespective of the type of the forest ecosystem, α-pinene was among the dominant monoterpenes emitted from all nine forests.

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  • IPEN-DOC 27239

    MARTINS, E.W. ; BUENO, L.K. ; POTIENS, M.P.A. . Implementation of an installation for the new activimeter calibration methodology. Brazilian Journal of Radiation Sciences, v. 8, n. 1A, p. 1-7, 2020. DOI: 10.15392/bjrs.v8i1A.917

    Abstract: Considering the frequent development of research projects and the services provided by the Instrument Calibration Laboratory (LCI), to implement the calibration of activity measuring instruments, it was necessary to build a new dedicated laboratory for this purpose. After the layout project carried out, the physical installations were started, following the radiological protection service plans according to the National Nuclear Energy Commission rules . In order to ensure greater reliability in the measurements and to facilitate the transport of radioactive sources, a new methodology of in situ calibration and quality control of activimeters was developed. This paper presents the implementations made in the new LCI installation for the implementation of the new activitymeter calibration methodology operationalization.

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  • IPEN-DOC 27238

    DOMINGUES, LUCAS G. ; GATTI, LUCIANA V. ; AQUINO, AFONSO ; SÁNCHEZ, ALBER; CORREIA, CAIO ; GLOOR, MANUEL; PETERS, WOUTER; MILLER, JOHN; TURNBULL, JOCELYN; SANTANA, RICARDO ; MARANI, LUCIANO; CÂMARA, GILBERTO; NEVES, RAIANE; CRISPIM, STÉPHANE. A new background method for greenhouse gases flux calculation based in back-trajectories over the Amazon. Atmosphere, v. 11, n. 7, p. 1-8, 2020. DOI: 10.3390/atmos11070734

    Abstract: The large amount of carbon stored in trees and soils of the Amazon rain forest is under pressure from land use as well as climate change. Therefore, various efforts to monitor greenhouse gas exchange between the Amazon forest and the atmosphere are now ongoing, including regular vertical profile (surface to 4.5 km) greenhouse gas measurements across the Amazon. These profile measurements can be used to calculate fluxes to and from the rain forest to the atmosphere at large spatial scales by considering the enhancement or depletion relative to the mole fraction of air entering the Amazon basin from the Atlantic, providing an important diagnostic of the state, changes and sensitivities of the forests. Previous studies have estimated greenhouse gas mole fractions of incoming air (‘background’) as a weighted mean of mole fractions measured at two background sites, Barbados (Northern Hemisphere) and Ascension (Southern hemisphere) in the Tropical Atlantic, where the weights were based on sulphur hexafluoride (SF6) measured locally (in the Amazon vertical profiles) and at the two background sites. However, this method requires the accuracy and precision of SF6 measurements to be significantly better than 0.1 parts per trillion (picomole mole􀀀1), which is near the limit for the best SF6 measurements and assumes that there are no SF6 sources in the Amazon basin. We therefore present here an alternative method. Instead of using SF6, we use the geographical position of each air-mass back-trajectory when it intersects the limit connecting these two sites to estimate contributions from Barbados versus Ascension. We furthermore extend the approach to include an observation site further south, Cape Point, South Africa. We evaluate our method using CO2 vertical profile measurements at a coastal site in Brazil comparing with values obtained using this method where we find a high correlation (r2 = 0.77). Similarly, we obtain good agreement for CO2 background when comparing our results with those based on SF6, for the period 2010–2011 when the SF6 measurements had excellent precision and accuracy. We also found high correspondence between the methods for background values of CO, N2O and CH4. Finally, flux estimates based on our new method agree well with the CO2 flux estimates for 2010 and 2011 estimated using the SF6-based method. Together, our findings suggest that our trajectory-based method is a robust new way to derive background air concentrations for the purpose of greenhouse gas flux estimation using vertical profile data.

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  • IPEN-DOC 27237

    EL HAJJ, THAMMIRIS M.; GANDOLLA, MAURO P.A.; SILVA, PAULO S.C. da ; JULIÃO, EDUARDO L.; VILLANUEVA, JOSÉ-LUIZ G.; DELBONI JUNIOR, HOMERO. A method for radiologically evaluating indoor use of dimension stone considering radon exhalation rates. Journal of the European Radon Association, v. 1, p. 1-15, 2020. DOI: 10.35815/radon.v1.3632

    Abstract: Background: The use of natural radioactive building materials could be a health risk for both dwellers and mining workers. Therefore, a quick and effective method to test batches of rock samples is needed. Nevertheless, there is no reference value for maximum exhalation rates for building materials, except radiological hazard indices that do not measure gas exhalation rates directly. Objectives: This article investigated the correlations between Gamma Index and radon and thoron exhalation rates, and the proportions of radon and thoron in samples. Moreover, the main objectives were to analyze the feasibility of screening problematic samples for indoor use through a portable radiation detector (CoMo 170), which consists of a quick analysis at very low cost, and to simulate indoor concentration of radon using the measured exhalation rates of dimension stone slabs. Design: Best-selling dimension stone slabs were submitted to the following assays: gamma spectrometry, radon and thoron exhalation analysis using scintillation cell, and radioactivity measurement using a portable detector. Univariate and multivariate statistical analyses were conducted using Statistica 13 software. Results: The average activity concentrations measured were 971 ± 58.6 Bq/kg of 40K, 184 ± 9 Bq/kg of 232Th, and 74 ± 3 Bq/kg of 226Ra. The maximum activity concentrations of 40K, 232Th, and 226Ra series were 1,734 ± 100 Bq/kg, 2,667 ± 109 Bq/kg, and 596 ± 2 Bq/kg, respectively. The average exhalation rate of 222Rn was 406 ± 20 Bq/h m2. Conclusions: The main recommendations arising from this study are as follows: a portable radiation detector (CoMo 170) could be used as a screening method for selected samples; Gamma Index limit value = 1 for dimension stone slabs could be adopted when assessing radon and thoron exhalation; and the surface radon exhalation rate should be measured as a basis of recommendation for surface treatment before sales. Finally, thoron exhalations should be considered in radiological assessment, as 57% of the samples had higher thoron exhalation rates than radon.

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  • IPEN-DOC 27236

    SANTOS, W.S. ; NEVES, L.P.; PERINI, A.P.; CALDAS, L.V.E. . Uso de modelagem computacional para avaliação da exposição médica e ocupacional durante procedimento de cardiologia intervencionista. Brazilian Journal of Radiation Sciences, v. 8, n. 1A, p. 1-12, 2020. DOI: 10.15392/bjrs.v8i1A.1086

    Abstract: A cardiologia intervencionista (CI) é uma modalidade comum que utiliza imagens fluoroscópicas para o diagnóstico e a terapia de problemas cardiovasculares. Embora os equipamentos de fluoroscopia mais modernos empreguem sistema de redução de dose, além de feixes bem colimados, a radiação espalhada atinge órgãos circundantes do paciente que não estão localizados no feixe primário de radiação. A radiação espalhada pelo corpo do paciente acarreta a exposição ocupacional do médico intervencionista. A avaliação das exposições ocupacional e médica é importante para a determinação dos riscos e das consequências biológicas em diferentes órgãos e tecidos. Neste trabalho, a avalição foi feita por meio do conceito de coeficiente de conversão (CC). Para quantificar os valores de CC, foi utilizado o programa computacional MCNPX e o simulador antropomórfico masculino virtual adulto (MASH3), para representar o paciente e o médico. Os resultados comprovaram a eficiência da proteção dos equipamentos suspensos. Quando não utilizados, um aumento dos valores de CC de dose efetiva podem ser superiores a 1000%.

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  • IPEN-DOC 27235

    NOVAIS, BRUNA; FERRAZ, EDWARD; SOUZA, ADELMO S.; ANTONIO, PATRICIA L. ; CALDAS, LINDA V.E. ; BATISTA, JOÃO; LIMA, HEVESON. Influence of the photoionization cross-section on the OSL signal of LiF: a theoretical and experimental approach. Optical Materials, v. 102, p. 1-6, 2020. DOI: 10.1016/j.optmat.2020.109792

    Abstract: The understanding of the electron trapping and recombination processes is the key to successful applications of materials in ionizing radiation dosimetry, which unfortunately are not well known yet. In this work, the influence of the photoionization cross-section (𝜎) was investigated on the optically stimulated luminescence (OSL) response of the lithium fluoride (LiF) compound. The 𝜎 has been predicted through the expression proposed by Lima–Batista–Couto. In addition, OSL measurements were performed using the continuous-wave stimulation mode (CW-OSL), with 60 s of light stimulation. The samples were submitted to 10 Gy and 15 Gy of absorbed dose. Phonon dispersion and density calculations are presented by using the Density Functional Perturbation Theory. The results, obtained by a combination of different methodologies, show that the low sensitivity of LiF to the light stimulus (𝜆 = 470 nm) is due to the very low magnitude of 𝜎 at the used excitation wavelength. A comparison with Al2O3:C was also carried out, showing that the intensity and the pattern of the OSL curve decay are modified by the 𝜎. These results play an important role in understanding the luminescent properties of this material, and they open a new opportunity to improve the light sensitivity of this detector.

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  • IPEN-DOC 27234

    CARVALHO, ALLYSSON D. de; GUIMARÃES, GABRIELLE G.; ZEITUNI, CARLOS A. . Comportamento in vitro dos fungos do gênero candida diante dos radiotraçadores emissores gama utilizados na cintilografia pulmonar inalação/perfusão e seu perfil de sensibilidade frente a anfotericina b após a irradiação / In vitro behavior of candidal gender fungi before gamma radiotraachers used in inhalation / perfusion pulmonary scintilography and its sensitivity profile in front of amphotericin b after irradiation. Brazilian Journal of Health Review, v. 3, n. 2, p. 1493-1512, 2020. DOI: 10.34119/bjhrv3n2-014

    Abstract: Dentre as infecções fúngicas mais comuns, a candidíase é um sério problema de saúde pública em todo mundo. Uma das drogas mais utilizadas para o tratamento é a Anfotericina-B, que além de ser nefrotóxica, tem potencial de causar resistência da levedura a esse antifúngico. A cintilografia pulmonar de inalação/perfusão, é um dos exames atualmente utilizados para diagnóstico de tromboembolismo pulmonar. No entanto, pacientes com alterações respiratórias inespecíficas que realizam esse procedimento na tentativa de exclusão diagnóstica, podem estar diante de uma pneumonia fúngica, ainda não diagnosticada. A literatura é escassa quando se busca relacionar o comportamento das leveduras às baixas doses de radiação gama e seu perfil de resistência frente à Anfotericina B, após irradiadas. OBJETIVO: Avaliar o perfil comportamental dos fungos, “in vitro”, diante de baixas doses de radiação gama oriunda dos radiotraçadores utilizados em exames de cintilografia pulmonar inalação/perfusão e após a irradiação, em relação a Anfotericina B. METODOLOGIA: Estudo prospectivo de caso controle com cepas de Candida albicans distribuídas em três tubos de ensaio com quantidades idênticas acrescidas de solução salina e 40 mCi de 99mTc (Tecnécio meta estável) puro, 40 mCi de 99mTc-DTPA e 6 mCi de 99mTc-MAA respectivamente, mantendo um tubo de ensaio sem ser irradiado para fins de controle. Todo experimento sendo realizado em triplicata. Essa exposição à radiação se deu por 36 horas, acarretando seis meias-vidas do 99mTc, onde ao final da sexta meia-vida praticamente não se encontrou mais atividade radioativa significativa. Para as análises de cinética de crescimento e sensibilidade ao antifúngico foram utilizados os testes de Análise de Variância (ANOVA) baseada num modelo de medidas repetidas e o teste de Shapiro-Wilk. RESULTADOS: Houve diminuição do halo de crescimento dos fungos que foram irradiados em comparação ao grupo controle frente à Anfotericina B. Entretanto, os fungos não apresentaram um perfil previsível de crescimento e comportaram-se de maneiras distintas quando analisados entre os grupos (DTPA+Tc, Tc puro, MAA+ Tc, Controle), e também quando avaliados em relação aos tempos (0h, 2h, 4h, etc).

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  • IPEN-DOC 27233

    GONZALES-LORENZO, CARLOS D.; NASCIMENTO, LUANA F.; KODAIRA, SATOSHI; GOMES, MONISE B. ; WATANABE, SHIGUEO. Thermoluminescence studies of polycrystalline CaSiO3 pellets for photons and particle therapy beams. Radiation Physics and Chemistry, v. 177, p. 1-8, 2020. DOI: 10.1016/j.radphyschem.2020.109132

    Abstract: In this work, pellets of CaSiO3 have been produced for investigation as gamma radiation, proton, and carbon ions detector. They were then irradiated to gamma radiation using 137Cs and 60Co sources. Furthermore, pellets of CaSiO3 were exposed to 160 MeV proton and 290 MeV/n carbon ion beam from an upper synchrotron. Thermoluminescence (TL) responses of these pellets presented the same prominent peak at about 170 °C, and two possible high-temperature peaks at 270 and 320 °C when irradiated to gamma, proton, and carbon ion beam. Dose-response curve, minimum detectable dose (MDD), energy dependence, and dependence on the dose rate when irradiated with gamma radiation were evaluated in this material. Linear dose-response curves for proton and carbon ion irradiation have been compared to that of the gamma dose-response. In this way, the dose read out in Harshaw TL reader presented a good agreement with doses found using ion chamber in the case of proton beams and slightly less in the case of carbon beam due to the LET dependency. Furthermore, relative efficiencies of CaSiO3 for beam irradiation of proton and carbon ion display no dependence in the analyzed particle doses range.

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  • IPEN-DOC 27232

    BICCA, MARCOS M.; KALKREUTH, WOLFGANG; SILVA, TAIS F. da; OLIVEIRA, CHRISTIE H.E. de; GENEZINI, FREDERICO A. . Thermal and depositional history of Early-Permian Rio Bonito Formation of southern Paraná Basin – Brazil. International Journal of Coal Geology, v. 228, p. 1-22, 2020. DOI: 10.1016/j.coal.2020.103554

    Abstract: The Paraná Basin is a large volcano-sedimentary basin with a complex depositional history from Ordovician to the Cretaceous period. During Permian significant amounts of organic-rich beds accumulated within the Rio Bonito and Irati formations representing deposition in coastal (deltaic and barrier lagoon) and shallow marine environments, respectively. In this work, the thermal history of these beds is examined from 16 vitrinite reflectance analyses of coal beds (Rio Bonito Formation), integrated with previous data on coal rank, and 21 apatite fission-track (AFT) analyses, collected from 17 well profiles in the south of the Paraná Basin. Coal samples showed three different maturity levels. Two with reflectances of 0.4–0.6 and 0.6–0.8%Rr formed by the natural burial history of the basin (the latter is restricted to the Torres Syncline area). In contrast, the third group reached much higher values (1.0–5.0%Rr) related to intrusive igneous rocks. The AFT data show thermal consistency with the reflectance values. The sandstone samples related to the two lower reflectance patterns were partially reset, preserving AFT ages older than the stratigraphic age of the bed. Otherwise, the samples severely affected by the magmatism have Cretaceous and Early Cenozoic ages, but some were much younger than the last magmatic event, implying deep burial before cooling onset. The mean track length distribution of the partially reset samples is short due to the inheritance of tracks preserved from basement cooling history. However, the population of fully reset samples gives crucial information on the maximum temperature reached and the age when cooling started. At these conditions, around 1.0 to 3.0 km of the Paraná Basin sequences would have been removed from the surface of the studied areas by erosion since Cretaceous. Regional variations in the amounts of removed sections were controlled by the structural framework, mostly regional NW-SE and NE-SW oriented structures.

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  • IPEN-DOC 27231

    MAZZILLI, B.P. ; CAMPOS, M.P. ; NISTI, M.B. ; SAUEIA, C.H.R. ; MADUAR, M.F. . Radiological implications of using phosphogypsum as building material: a case study of Brazil. Brazilian Journal of Radiation Sciences, v. 8, n. 1, p. 1-29, 2020. DOI: 10.15392/bjrs.v8i1.1008

    Abstract: Phosphogypsum, a waste byproduct derived from the production of phosphoric acid, is being worldwide stock-piled, posing concerns about the environmental problems originating from this practice. Considerations about the viability of the safe reuse of this material have been raised, among them its potential use as building material. However, as phosphogypsum can contain natural radionuclides in significant concentrations, using it as a build-ing material has radiological implications, which presently prevent such application. In order to evaluate the feasibility of using phosphogypsum in the manufacturing of building elements such as bricks and plates, a com-prehensive research was undertaken in Brazil, following a multiple approach. This research included studies related to: Brazilian phosphogypsum characterization; experimental determination of radon exhalation rate; and application of theoretical models to forecast both radon exhalation and external doses in dwellers. In this paper, a comprehensive review of the research carried out in Brazil is presented.

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  • IPEN-DOC 27230

    GOMES, M.B. ; OLIVEIRA, L.M. ; CORTEZ, B. ; D'OCA, M.C.; TRANCHINA, L.; TOMARCHIO, E.; PARLATO, A.; CHUBACI, J.F.D.; GENNARI, R.; ROCCA, R.R.; D'ERRICO, F.; SOUSA, S.; WATANABE, S.; MARRALE, M.. EPR dating of shells from Malhada Marsh, Rio de Janeiro, Brazil. Annals of Marine Science, v. 4, n. 1, p. 008-013, 2020. DOI: 10.17352/ams.000018

    Abstract: The formation of the coastal plain of the Brazilian sea is mainly due to the fl uctuation of relative sea level in the past. Armação dos Buzios or simply Buzios is a municipality in the microregion of lakes, in the state of Rio de Janeiro. In this region there is a lowland area about two meters above current sea level. This lowland area is also known as coastal plain of Una River. It is expected that during the Holocene period the sea level reached a maximum about 2.5 meters above the current level. During that time billions of mollusks lived and proliferated in the shallow waters around the coastal plain of the Una River. As they died their shells formed a layer in the soil including Malhada Marsh that belongs to the Una River plain. In this study, shells were collected from this region and dated using the techniques of Electronic Paramagnetic Resonance (EPR). Ages from 2480±130 to 4490±270 years were obtained. Radiocarbon dating were performed at the Beta Analytic Lab, USA for comparison with the EPR results. Shells ages obtained are compatible with geological data from the Holocene period relative to past sea level fl uctuations.

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  • IPEN-DOC 27229

    OLIVEIRA, L.M. ; GOMES, M.B. ; CORTEZ, B. ; D'OCA, M.C.; TRANCHINA, L.; TOMARCHIO, E.; PARLATO, A.; CHUBACI, J.F.D.; GENNARI, R.; ROCCA, R.R.; D'ERRICO, F.; SOUSA, S.; WATANABE, S.; MARRALE, M.. Electron Spin Resonance and Thermoluminescence dating of shells and sediments from Sambaqui (shell mound) Santa Marta II, Brazil. Annals of Marine Science, v. 4, n. 1, p. 001-007, 2020. DOI: 10.17352/ams.000017

    Abstract: In Tupi, the word Sambaqui means “mound of shells”. These archaeological sites are cultural vestiges left by the prehistoric occupation of the Brazilian coast from fi ve to six thousand years ago. Mollusks, fi shes, and other marine edible foods were important for the survival of this population. The remains of foods, mainly shells, were heaped up, giving a mound of different proportions, which became part of the landscape of the Brazilian coastal plain. Due to the large number of Sambaquis in Brazil and considering that Sambaqui Santa Marta II, Laguna, SC, has not yet been dated, Electron Spin Resonance (ESR) measurements were performed in aragonite shells collected from different layers of Sambaqui Santa Marta II, starting from the base to the center of the Sambaqui. Radiocarbon analysis by Accelerator Mass Spectrometry (AMS) at Beta Analytic laboratory were also performed for comparison with ESR results. Before measurements, shells were chemically etched, after drying, were pulverized and sieved. The sediments were separated into small portions which were irradiated with gamma radiation from a 60Co source with doses from 5 up to 120 Gy. Ages around 2,000 to 4,000 years have been obtained. The results obtained are consistent with the dates of others Sambaquis of the region, possibly were built at the same time.

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  • IPEN-DOC 27228

    BRANT, ANTONIO J.C. ; NAIME, NATALIA ; LUGAO, ADEMAR B. ; PONCE, PATRICIA . Cellulose nanoparticles extracted from sugarcane bagasse and their use in biodegradable recipients for improving physical properties and water barrier of the latter. Materials Sciences and Applications, v. 11, n. 1, p. 81-133, 2020. DOI: 10.4236/msa.2020.111007

    Abstract: The present work firstly aimed to obtain cellulose from sugarcane bagasse by using alkaline methods in pulping/delignifying and, at bleaching stages, using sodium chlorite, glacial acetic acid, and hydrogen peroxide, associated to NaOH/KOH. The process was carried out at temperatures varying from 55˚C to 110˚C, under magnetic stirring in various steps lasting from 2 h to 12 h. The yields of the two cellulose extracted, SCB24-Na-I and SCB24-Na-II, were 37% and 41%, respectively, from samples of ca. 15 g of the bagasse. Secondly, it is to extract nanoparticles from the obtained celluloses via acid hydrolysis (with 77% H2SO4) to lately be tested as reinforcement in biodegradable packagings. Both celluloses and their respective nanoparticles were characterized by several techniques, among them ATR-FTIR, DSC-TGA, XRD, SEM, and TEM. Despite that the yields of cellulose nanoparticles have been low, the preliminary studies of their use in biodegradable films coated on biodegradable pots were promising.

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  • IPEN-DOC 27227

    CASTRO, DIONE P. de ; GARCIA, RAFAEL H.L. ; SILVA, LEONARDO G. de A. e . Characterization using X-ray diffraction and study of the crystallinity of the thermoplastic starch/poly(butylene adipate-co-terephthalate) blends irradiated by gamma rays / Caracterização por DRX e estudo de cristalinidade de blendas de amido termoplástico/poli (butileno adipato-co-tereftalato) irradiadas por raios gama. Brazilian Journal of Development, v. 6, n. 3, p. 9635-9643, 2020. DOI: 10.34117/bjdv6n3-005

    Abstract: The aim of this study was to analyze the changes in the structure and crystallinity of non-irradiated and irradiated thermoplastic starch blends (TPS)/poly (butylene adipate-co-terephthalate) - PBAT and also to evaluate the behavior of castor oil replacing glycerol. In this work, the characterization was performed by using X-ray diffraction (XRD), in which the crystallinity index (IC) of non-irradiated and irradiated blends of TPS/PBAT was calculated, through the software Bruker DIFFRAC.EVA® v4.22. For the plastification of the TPS, glycerol, castor oil and TWEEN® 80 were used to verify their compatibility and establish a comparison among the blends. The samples were prepared by extrusion and irradiated at 25 kGy with gamma rays with a 60Co source. However, the crystallinity indexes of the blends were altered according to the plasticizer used and the use of TWEEN® 80. Thus, it was concluded that replacing glycerol with castor oil is feasible in TPS/PBAT blends.

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  • IPEN-DOC 27226

    LOPES, DANIELA S.; PEREIRA, DAISA L. ; MOTA, CLAUDIA C.B.O.; MELO, LUCIANA S.A.; ANA, PATRICIA A.; ZEZELL, DENISE M. ; GOMES, ANDERSON S.L.. Surface evaluation of enamel etched by Er,Cr:YSGG laser for orthodontic purpose. The Journal of Contemporary Dental Practice, v. 21, n. 3, p. 227-232, 2020. DOI: 10.5005/jp-journals-10024-2777

    Abstract: Aim: To compare the effect of erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser at different irradiation parameters and acid etching on the shear bond strength (SBS) of orthodontic brackets to enamel. Materials and methods: Forty bovine incisors were randomly distributed into groups (n = 10): GI: 37% phosphoric acid etching; GII: Er,Cr:YSGG laser etching 19.1 J/cm2; GIII: Er,Cr:YSGG, 29.3 J/cm2; and GIV: Er,Cr:YSGG, 42.4 J/cm2. After treatments, metallic brackets were bonded using Transbond XT adhesive system. After light curing, the samples were subjected to 500 thermal cycles, debonded with a universal testing machine, and the SBS values were recorded. After debonding, surface morphology was evaluated using scanning electron microscopy (SEM) and optical coherence tomography (OCT). The values of SBS testing were analyzed by one-way analysis of variance (ANOVA) and Tukey post hoc test, at 5% significance level. Results: The mean SBS values of GI, GII, GIII, and GIV groups were 6.2 ± 1.7 MPa, 4.6 ± 2.5 MPa, 7.0 ± 2.2 MPa, and 8.0 ± 3.6 MPa, respectively. Laser irradiation promoted rough surfaces in all parameters used, and the OCT analysis revealed higher optical changes on lased groups when compared with phosphoric acid. Conclusion: Er,Cr:YSGG laser irradiation operated at 42.4 J/cm2 and 29.3 J/cm2 is a better alternative for etching enamel prior to the orthodontic treatment than the phosphoric acid. Clinical significance: Er,Cr:YSGG laser irradiation is better than the phosphoric acid for etching enamel prior to the orthodontic treatment because laser irradiation promotes similar SBSs and preventing demineralization around orthodontic brackets.

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  • IPEN-DOC 27225

    FANTON, LEONARDO; LIMA, NELSON B. de ; ENCINAS, EMILIO R.; BORRÁS, VICENTE A.; AFONSO, CONRADO R.M.; FOGAGNOLO, JOÃO B.. Effects of laser surface melting on crystallographic texture, microstructure, elastic modulus and hardness of Ti−30Nb−4Sn alloy. Transactions of Nonferrous Metals Society of China, v. 30, n. 2, p. 392-404, 2020. DOI: 10.1016/S1003-6326(20)65221-9

    Abstract: The biocompatibility of orthopedic implants is closely related to their elastic modulus and surface properties. The objective of this study was to determine the effects of cold rolling, recrystallization and laser surface melting (LSM) on the microstructure and mechanical properties of a biphase (α″+β) Ti−30Nb−4Sn alloy. X-ray diffraction (XRD) texture analysis of the cold-rolled substrate revealed the [302]α″//ND texture component, while analysis of the recrystallized substrate showed the [302]α″//ND and [110]α″//ND components. The β-phase texture could not be directly measured by XRD, but the presence of the [111]β//ND texture component was successfully predicted by considering the orientation relationship between the α″ and β phases. Nanoindentation measurements showed that the elastic modulus of the cold-rolled substrate (63 GPa) was lower than that of the recrystallized substrate (74 GPa). Based on the available literature and the results presented here, it is suggested that this difference is caused by the introduction of crystal defects during cold deformation. The combined nanoindentation/EBSD analysis showed that the nanoindentation results are not affected by crystal orientation. LSM of the deformed alloy produced changes in hardness, elastic modulus and crystallographic texture similar to those produced by recrystallization heat treatment, creating a stiffness gradient between surface and substrate.

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  • IPEN-DOC 27224

    THOMAZI, GABRIELA O.C. ; COSTA, ANDREA da; RODRIGUES, JAQUELINE P.; ALVES, GLAUCIE J. ; PREZOTTO NETO, JOSE P. ; TURIBIO, THOMPSON de O. ; ROCHA, ANDRE M. ; AIRES, RAQUEL da S. ; SEIBERT, CARLA S.; SPENCER, PATRICK J. ; GALISTEO JUNIOR, ANDRES J.; ANDRADE JUNIOR, HEITOR F. de; NASCIMENTO, NANCI do . Paratrygon aiereba irradiated anti-mucus serum reduce edematogenic activity induced in experimental model. Toxicon, v. 178, p. 13-19, 2020. DOI: 10.1016/j.toxicon.2020.02.012

    Abstract: Accidents by freshwater stingrays are common in northern Brazil, there is no specific therapy for high morbidity and local tissue destruction. The irradiation of venoms and toxins by ionizing radiation has been used to produce appropriate immunogens for the production of antisera. We planned to study the efficacy of stinging mucus irradiation in the production of antisera, with serum neutralization assays of edematogenic activity and quantification of cytokines performed in animal models of immunization with native and irradiated mucus of Paratrygon aiereba, a large freshwater stingray. Antiserum potency and its cross-reactivity with mucus from other freshwater stingrays were detected by ELISA. Immunization models demonstrated the ability to stimulate a strong humoral response with elevated levels of serum IgG detectable by ELISA, and both native and irradiated mucus were immunogenic and capable of recognizing mucus proteins from other freshwater neotropical stingrays. Mucus P. aiereba causes cellular and humoral adaptive immune responses in cells of immunized mice producing antibodies and cytokines such as TNF-α, IL-6 and IL-17. Rabbit antisera immunized with mucus from P. aiereba irradiated at 2 kGy showed a significant reduction of mucus-induced edematogenic activity in mice. Our data suggest that the use of antisera against freshwater stingray mucus show the possibility of specific therapy for these accidents.

    Palavras-Chave: fishes; venoms; toxicity; immunity; immunoassay; gamma radiation; immune serums; enzyme immunoassay; fresh water; aquatic ecosystems; antibodies; ionizing radiations

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  • IPEN-DOC 27223

    MACHADO, JOÃO P.S.L.; JELINEK, ANDRÉA R.; STEPHENSON, RANDELL; GAUCHER, CLAUDIO; BICCA, MARCOS M.; CHIGLINO, LETICIA; GENEZINI, FREDERICO A. . Low-temperature thermochronology of the South Atlantic margin along Uruguay and its relation to tectonic events in West Gondwana. Tectonophysics, v. 784, p. 1-21, 2020. DOI: 10.1016/j.tecto.2020.228439

    Abstract: The geodynamic forces acting during Jurassic-Cretaceous South Atlantic rifting provoked intense transformations in West Gondwana, such as the reactivation of ancient basement structures, voluminous magmatism and general uplift of the new continental margins. Low-temperature thermochronology records cooling associated with uplift syn- and post-breakup along the Brazilian margin, while further south, in Uruguay, mostly prebreakup uplift is identified. Thermochronometry data are scarce in Uruguay, but previous studies suggest that basement cooling and exhumation preceded West Gondwana breakup by hundreds of millions of years. To improve our knowledge of Uruguay's thermotectonic evolution, in this study we present 19 apatite fission-track ages, 42 apatite and 40 zircon (UeTh)/He single crystal ages for the Uruguayan shield (UYS), from which we modeled 19 inverse thermal histories. Our results suggest that the UYS temperatures were below 200 °C since the early Paleozoic, and that cooling below 110 °C started during the Carboniferous, with continuous exhumation of the basement until Early Cretaceous. The onset of this long-term uplift is correlated with orogenesis and terrane accretions in the SW margin of West Gondwana during the Paleozoic. Lithosphere thinning and uplift preceding breakup contributed to the continuous Late Paleozoic to middle Mesozoic exhumation, until the voluminous volcanism of the Paraná-Etendeka Large Igneous Province (c. 133 Ma). This magmatic event, combined with the thermal influence of the Tristão da Cunha mantle plume and rift spreading, likely raised the basement geotherm during the Late Cretaceous. Models suggest a slight increase in temperatures of the UYS from Late Cretaceous until the Oligocene, when a final cooling to surface temperatures took place. Our findings corroborate a long and complex thermal history for Uruguay, with crustal uplift occurring essentially before West Gondwana breakup.

    Palavras-Chave: tectonics; geology; gondwana; age estimation; fission tracks; apatites; zircon; uruguay; paleozoic era

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  • IPEN-DOC 27222

    SILVA, F.C. da; TUNES, M.A.; EDMONDSON, P.D.; LIMA, N.B. ; SAGÁS, J.C.; FONTANA, L.C.; SCHÖN, C.G.. Grid-assisted magnetron sputtering deposition of nitrogen graded TiN thin films. SN Applied Sciences, v. 2, n. 5, 2020. DOI: 10.1007/s42452-020-2617-3

    Abstract: Titanium Nitride (TiN) films were obtained using the grid-assisted magnetron sputtering deposition technique on Al substrates in two conditions: under constant and variable nitrogen concentration along the thin solid film thickness. The formation of a film with variable N concentration (herein referred as graded film) was confirmed using energy filtered transmission electron microscopy, X-ray photoelectron spectroscopy and grazing incidence X-ray diffraction. The TiN thin films microstructures were also analysed using scanning and transmission electron microscopies (SEM and TEM). The viability of synthesizing TiN thin films with variable N concentration is herein proposed as an alternative method for tailoring the properties of such functional coating materials.

    Palavras-Chave: titanium nitrides; tin; thin films; transmission electron microscopy; electron microscopy; x-ray photoelectron spectroscopy; magnetrons; microstructure; scanning electron microscopy

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  • IPEN-DOC 27221

    LAVEZZO, BRUNA; KINOSHITA, ANGELA; FIGUEIREDO, ANA M.G. ; PINHEIRO, MAYARA M.F.; SANTANA, WILLIAM. Detection of rare-earth elements using fiddler crabs Leptuca leptodactyla (Crustacea: Ocypodidae) as bioindicators in mangroves on the coast of São Paulo, Brazil. Science of the Total Environment, v. 738, p. 1-9, 2020. DOI: 10.1016/j.scitotenv.2020.139787

    Abstract: Rare-earth elements have gained significant attention as they are currently widely used in high tech, chemical, and pharmaceutical industries. Here we used the fiddler crabs Leptuca leptodactyla as bioindicators to verify the presence of rare-earth elements in two mangrove areas of the Ubatuba, northern littoral of São Paulo state, Brazil. The specimens were collected in the mangrove areas of the Tavares River and Quiririm-Puruba river system, separated by season (dry and rainy). A total of 243 individuals were collected and analyzed. For determination and quantification of the elements we used the instrumental neutron activation analysis (INAA) technique. In both the dry and rainy season, the elements La, Ce, Sm, Eu, Tb, Yb and Scwere detected in samples of bothmangroves, with La and Ce presenting higher concentrations. Samples from Tavares River mangrove had higher concentration levels of rare-earth elements than those of the Quiririm-Puruba river system. That is probably due to the central geographic position of the Tavares River in Ubatuba, which crosses a large portion of the city and receives a great amount of sewage. On the other hand, the Quiririm-Puruba river system has less anthropogenic inputs, thus, it receives much fewer rare-earth elements when compared to the Tavares River.

    Palavras-Chave: biological markers; mangroves; rare earths; estuaries; aquatic ecosystems; measuring instruments; neutron activation analysis; environment; coastal waters; crabs; sediments; metals; elements; trace amounts

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  • IPEN-DOC 27220

    SOUZA, FELIPE de M.; SOUZA, RODRIGO F.B. de ; BATISTA, BRUNO L.; SANTOS, MAURO C. dos; FONSECA, FABIO C. ; OLIVEIRA NETO, ALMIR ; NANDENHA, JULIO . Methane activation at low temperature in an acidic electrolyte using PdAu/C, PdCu/C, and PdTiO2/C electrocatalysts for PEMFC. Research on Chemical Intermediates, v. 46, n. 5, p. 2481-2496, 2020. DOI: 10.1007/s11164-020-04102-1

    Abstract: Pd/C, PdAu/C, PdCu/C, and PdTiO2/ C electrocatalysts were prepared by a sodium borohydride reduction process for methane activation at low temperatures in a PEMFC reactor. These electrocatalysts were characterized by XRD, TEM, XPS, ICP-MS, ATR-FTIR, and cyclic voltammetry. The diffractograms of Pd/C, PdAu(50:50)/C, PdCu(50:50)/C, and PdTiO2( 50:50)/C electrocatalysts showed peaks associated with Pd face-centered cubic structure. PdAu(50:50)/C showed a small shift in the peak center when it was compared to Pd/C, while PdCu(50:50)/C showed a shift to higher angles when it was also compared to Pd/C. This effect can be due to the formation of an alloy between Pd and Au, and Pd and Cu. By TEM experiments, a mean nanoparticle size was observed between 6.9 and 8.9 nm for all electrocatalysts. Cyclic voltammograms of Pd/C, PdAu/C, PdCu/C and PdTiO2/ C electrocatalysts showed an increase in current density values after the adsorption of methane The ATR-FTIR experiments showed for all electrocatalysts the formation of methanol and formic acidic. Polarization curves at 80 °C acquired in a PEMFC reactor showed that PdAu(50:50)/C and PdTiO2( 50:50)/C had superior performance when compared to Pd/C, indicating the beneficial effect of adding the co-catalyst; this behavior has been attributed to the bifunctional mechanism or electronic effect.

    Palavras-Chave: methane; electrocatalysts; borohydrides; sodium compounds; binary alloy systems; palladium alloys; gold alloys; copper alloys; titanium oxides; proton exchange membrane fuel cells; temperature range 0065-0273 k; fourier transformation; infrared spectra; attenuation; reflection

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  • IPEN-DOC 27219

    SOUZA, FELIPE M.; NANDENHA, JULIO ; OLIVEIRA, VITOR H.A.; PAZ, EDSON C.; PINHEIRO, VICTOR S.; AVEIRO, LUCI R.; PARREIRA, LUANNA S.; SILVA, JULIO C.M.; BATISTA, BRUNO L.; NETO, ALMIR O. ; SANTOS, MAURO C.. The effect of support on Pd1Nb1 electrocatalysts for ethanol fuel cells. Renewable Energy, v. 150, p. 293-306, 2020. DOI: 10.1016/j.renene.2019.12.110

    Abstract: Pd1Nb1/C on different kinds of carbon black were prepared by a modified sol-gel method. The alkaline direct ethanol fuel cell (ADEFC) performance was performed first with the Pd1Nb1 electrocatalysts and then by varying the fuel concentration. In CV, Pd1Nb1/Printex 6L (50:50 wt%) exhibited 2.2 times higher mass activity than that of the Pd/C (Alfa Aesar); their mass activities were 1300 and 590 mA mg 1 Pd , respectively. The best performance for the ADEFC was obtained using Pd1Nb1/Printex 6L, which yielded a maximum power density and cell voltage of 28 mW cm 2 and 1.17 V, respectively. The Pd1Nb1/Printex 6L electrocatalyst exhibited a more negative onset potential for the CO stripping reaction. We suggest that the higher hydrophilicity (contact angle) and higher degree of disorder of Printex 6L (Raman) corroborates these results. In addition, both bifunctional and electronic effects operated on the electrocatalyst due to the presence of metal oxides and alloys of PdNb (XRD), respectively, in the synthesized electrocatalysts. Therefore, it was notable that the support has an essential roledas important as the cocatalystdin the electrocatalytic performance.

    Palavras-Chave: ethanol fuels; direct ethanol fuel cells; ethanol; oxidation; palladium; niobium; sol-gel process; electrochemistry; electrocatalysts

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  • IPEN-DOC 27218

    ANDRADE, M.A.B.; SAVI, M. ; ALVES, C.O.; FIN, A.P.C.; SOARES, F.A.P.; POTIENS, M.P.A. . Impact of infill percentages in visual homogeneity for 3D printed imaging phantoms. Brazilian Journal of Radiation Sciences, v. 8, n. 1A, p. 1-10, 2020. DOI: 10.15392/bjrs.v8i1A.919

    Abstract: The main goal of a 3D printed imaging phantom is to attenuate the radiation in order to differentiate tissues of the human body. This paper aims to verify the infill printing parameter in relation to its final homogeneity in printed samples. Sixteen 8 cm³ cubes with 15% to 90% infill variation, with 5% increments, were printed on PLA + Copper (Cu) and pure ABS. The samples were irradiated using a CT scan at 120 kV, 200 mA, 0.4 mm sections and reconstructed with standard filter. For each cube the mean values of Hounsfield Units (HU) and standard deviation (SD) in a Region of Interest (ROI) were determined. Visually, the internal lattice of each cube was assessed by counting line pairs per millimeter (lp/mm) using a DICOM viewer. Infill values above 50% for PLA + Cu and 55% for ABS showed a high homogeneity that does not allow line pair differentiation. In conclusion, values above and including the found percentages are recommended for use in construction of imaging phantoms.

    Palavras-Chave: acrylonitrile; butadiene; computerized tomography; copper; filaments; fillers; lactic acid; phantoms; radiology; simulation; styrene; three-dimensional calculations

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  • IPEN-DOC 27217

    OTERO, A.G.L. ; POTIENS JUNIOR, A.J. ; MARUMO, J.T. . Um comparativo entre a utilização de redes neurais perceptron e redes neurais profundas na identificação de radionuclídeos em espectrometria gama. Brazilian Journal of Radiation Sciences, v. 8, n. 1, p. 1-11, 2020. DOI: 10.15392/bjrs.v8i1.1132

    Abstract: Apresentamos os resultados da comparação entre uma Rede Neural Profunda e uma Rede Neural Perceptron na classificação de espectros gama obtidos utilizando um detector de germânio hiper-puro. Utilizando dados de diversas fontes seladas (Am-241, Ba-133, Cd-109, Co-57, Co-60, Cs-137, Eu-152, Mn-54, Na-24, and Pb-210) foram gerados uma lista extensa de espectros para treino e validação contendo, respectivamente, 500 e 160 espectros, onde foram mesclados até três radionuclídeos em um único espectro. Depois de 250 épocas de treino foram validadas a exatidão de cada um dos modelos utilizando o conjunto de validação. O modelo de rede neural profunda obteve uma exatidão de classificação de 96,25% enquanto a rede neural perceptron obteve uma exatidão de 80,62%. Os resultados mostram um desempenho robusto e consistentemente melhor das redes neurais profundas, frente as redes neurais perceptron.

    Palavras-Chave: chemical analysis; comparative evaluations; data; gamma spectroscopy; high-purity ge detectors; neural networks; sealed sources

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  • IPEN-DOC 27216

    SOARES, MARIA R. ; SANTOS, WILLIAM S. ; NEVES, LUCIO P.; PERINI, ANA P.; BATISTA, WILSON O.G.; MAIA, ANA F.; BELINATO, WALMIR; CALDAS, LINDA V.E. . The use of personal protection equipment for the absorbed doses of eye lens and thyroid gland in CBCT exams using Monte Carlo. Radiation Physics and Chemistry, v. 167, p. 1-6, 2020. DOI: 10.1016/j.radphyschem.2019.108347

    Abstract: The purpose of this study was to evaluate the absorbed dose in the thyroid and eye lens when the patient uses individual protection. For this purpose, Monte Carlo (MC) simulation was employed using five different field of view (FOV) sizes, available in the i-Cat classic CBCT equipment. To represent the patient, a male virtual anthropomorphic phantom was used. Three different models of lead eyewear and thyroid shield were evaluated, as well as the dose difference with and without the personal protection equipment. The difference in the absorbed dose in relation to the use of the lead eyewear presented a reduction of 19% for the 8 cm×6 cm FOV (diameter×height), and 73% for the 14 cm×22 cm FOV. In relation to the thyroid, only the shield that involved the whole neck contributed to the reduction of the absorbed dose by up to 72% for a 14 cm×22 cm FOV. For the thyroid shields there was a maximum increase of 59% (14 cm×6 cm FOV), consequently, increasing the effective dose for the protocol. The results showed that the lead eyewear contributed to the protection of the eye lens, but the efficiency of the thyroid shield depends on several factors, as FOV and shield model.

    Palavras-Chave: radiation protection; computerized tomography; monte carlo method; simulation; protective clothing; equipment; eyes; phantoms; neck

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  • IPEN-DOC 27215

    POLO, IVON O. ; CALDAS, LINDA V.E. . SOL-GEL α-Al2O3 detectors: TL and OSL response to beta radiation beams. Radiation Physics and Chemistry, v. 167, p. 1-7, 2020. DOI: 10.1016/j.radphyschem.2019.02.019

    Abstract: The dosimetric properties of the SOL-GEL α-Al2O3 detectors with several different concentrations of impurities were studied in beta radiation beams. For the characterization of the detectors, the TL and OSL techniques were used. A TL spectrum was acquired. The detectors showed adequate OSL and TL dosimetric characteristics, such as good reproducibility, a glow curve with the peak at ~230 °C at 5 °C/s of heating rate, adequate OSL decay curve, good linearity of response and high phosphor sensitivity. A thermal treatment study was also performed. Moreover, the calibration factors and the lower detection limits were determined for beta radiation. These characteristics indicate the suitability of SOL-GEL α-Al2O3 detectors for the establishment of a transfer system or alternative/complementary method for beta radiation dosimetry.

    Palavras-Chave: sol-gel process; radiation detectors; aluminium oxides; dosemeters; radiations; beta particles; beta sources; thermoluminescence; luminescence; stimulated emission

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  • IPEN-DOC 27214

    ALVARENGA, TALLYSON S. ; POLO, IVON O. ; PEREIRA, WALSAN W.; CALDAS, LINDA V.E. . Use of Monte Carlo simulation and the Shadow-Cone Method to evaluate the neutron scattering correction at a calibration laboratory. Radiation Physics and Chemistry, v. 170, p. 1-4, 2020. DOI: 10.1016/j.radphyschem.2019.108624

    Abstract: The calibration of radiation detectors is performed with the aim of ensuring accurate measurements of different types of radiation. Due to scattering neutrons, the neutron beam spectrum will not be the same spectrum as that emitted by the neutron source, thus influencing the reading of the instrument to be calibrated and causing a systematic error in the calibration of the neutron measurement devices. The objective of the present work was to estimate the contribution of scattering neutron radiation to fluence and mean energy using the Monte Carlo simulation and the Shadow-Cone Method with the objective of obtaining direct and scattering counting rates. The counting rates obtained at the Neutron Calibration Laboratory at IPEN, using the Bonner sphere spectrometer, were inserted into the NeuraLN program, which uses the UTA-4 response matrix and has 81 bins of energy used to determine the spectrum, fluence rate, and mean energy at the source-detector distances of 100 cm and 150 cm.

    Palavras-Chave: monte carlo method; scattering; calibration; neutron detectors; neutron beams; neutron spectra; neutron sources; cones; shadow effect

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  • IPEN-DOC 27213

    COSTA, NATHALIA A. ; PATALLO, ILEANA S.; DIMITRIADIS, ALEX; SARAIVA, CRYSTIAN W.C.; POTIENS, MARIA da P.A. . Phantom development and implementation for Gamma Knife® dosimetry. Radiation Physics and Chemistry, v. 167, p. 1-5, 2020. DOI: 10.1016/j.radphyschem.2019.108355

    Abstract: Stereotactic radiosurgery is a procedure that primarily treats intracranial lesions to destroy tumour cells that are inaccessible surgically. Gamma Knife® is a stereotactic radiosurgery unit that can treat brain lesions using 60Co beams, non-invasively. Fields from Gamma Knife® helmets are considered small, therefore, in order to ensure accurate dosimetry, detectors for dose measurements have to be carefully chosen. The IAEA TRS 483 code of practice is a standardized guide for dosimetric procedures and indication of detectors for reference dosimetry of small fields used in radiotherapy beams. The objective of this work was to assess the implementation of the TRS 483 recommendations for Gamma Knife® dosimetry, using two micro-ionization chambers, Exradin A16 and PTW Pinpoint 3D 31016. An acrylic phantom with the same dimensions as those provided by Elekta, Gamma Knife’s manufacturer, was built as an alternative. The phantom was characterized for its implementation for Gamma Knife® dosimetry and to be used as part of an audit kit by a Secondary Standard Dosimetry Laboratory (SSDL) in Brazil. Alanine pellets were used as reference detector. Dosimetry results for the acrylic phantom were compared with the ones obtained in phantoms specified by Elekta, which are made of Acrylonitrile Butadiene Styrene (ABS) and Solid Water materials. TRS 483 recommended correction factors were used to calculate the absorbed dose to the water taking into consideration the phantom material. Absorbed dose measurements performed using the designed acrylic phantom showed results comparable to the ones obtained with commercially available phantoms. The new phantom is suitable for Gamma Knife reference and relative dosimetry. The results of this work aim to contribute to the implementation of the TRS 483, mainly in the area of Gamma Knife dosimetry and the use of small volume ionization chambers.

    Palavras-Chave: radiant flux density; gamma radiation; radiation dose units; radiation sources; dosimetry; radiation protection; small intestine; phantoms; biological models; nuclear medicine; radiotherapy; surgery; brain

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  • IPEN-DOC 27212

    SILVA, ROGERIO M.V.; BELINATO, WALMIR; SANTOS, WILLIAM S. ; SOUZA, LUIZA F.; PERINI, ANA P.; NEVES, LUCIO P.; SOUZA, DIVANIZIA N.. Low cost electron irradiator using 90Sr+90Y sources. Radiation Physics and Chemistry, v. 167, p. 1-8, 2020. DOI: 10.1016/j.radphyschem.2019.03.039

    Abstract: In beta therapy, β particles from 90Sr+90Y are used for the prevention and treatment of ophthalmological and dermatological diseases. For such purposes, the radiation dose is deposited by planar and concave applicators positioned on the region to be treated. Although this therapy is effective on the diseases, several complications have been reported, making these types of radioactive applicators obsolete in current clinical practice. This paper proposes a methodology to prepare and evaluate the safety of a research irradiator that re-purposes and adapts dermatologic and ophthalmic 90Sr+90Y applicators. The irradiator was constructed using low cost materials and three applicator sources. The sources are positioned at the center and the upper end of acrylic rectangular prisms. Radiochromic film was used to obtain the dose distribution on the sample holder surface. Pellets of aluminum oxide doped with carbon (Al2O3:C) were used to evaluate the reproducibility of the irradiator. The MCNPX Monte Carlo code was used for the evaluation of safety conditions. The irradiator exhibits good reproducibility of irradiation of dosimeters in pellet form and is safe to handle.

    Palavras-Chave: brachytherapy; strontium 90; yttrium 90; monte carlo method

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  • IPEN-DOC 27211

    RAO, INA P.; ARMELIN, MARIA J.A. ; MASTRO, NELIDA L. del . Impact of ionizing radiation on cake from Brazilian macadamia nut (Macadamia integrifolia) after oil extraction. Radiation Physics and Chemistry, v. 172, p. 1-4, 2020. DOI: 10.1016/j.radphyschem.2020.108813

    Abstract: Macadamia oil extraction is commonly performed by cold pressing. This process presents low extraction yields, generating partially defatted meal as a byproduct. To take advantage of their important nutritious components, we propose to use the cake after lipid extraction as a food ingredient following the elimination of potentially hazardous microbiological contamination. Food irradiation is a mature, effective, broad spectrum and residuefree technology that can play an important role in food safety and food security. This study presents the impact of gamma irradiation on the residual cake from Brazilian macadamia pressing. An absorbed dose of 5 kGy reduced yeasts, molds and aerobic mesophilic bacteria below admissible maxima. The concentration of important elements like Ca, Se, Mg or Mn appeared higher in the cake than in the nut itself as measured by instrumental neutron activation analysis (INAA).

    Palavras-Chave: nuts; oils; food; ionizing radiations; nutrition; nutrients; microorganisms; quantitative chemical analysis; neutron activation analysis; chemical composition

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  • IPEN-DOC 27210

    SANTOS, CARLA J.; SANTOS, WILLIAM S. ; PERINI, ANA P.; VALERIANO, CAIO C.S. ; BELINATO, WALMIR; CALDAS, LINDA V.E. ; NEVES, LUCIO P.. Evaluation of polymer gels using Monte Carlo simulations. Radiation Physics and Chemistry, v. 167, p. 1-4, 2020. DOI: 10.1016/j.radphyschem.2019.03.038

    Abstract: The use of Monte Carlo simulations in dosimetry is a well established area of research, and several correction factors, for ionization chambers, were evaluated with these simulations. Some simulated values were considered even more reliable than the experimental measurements. Besides these uses with ionization chambers, Monte Carlo simulations may also be employed in the development and characterization of new dosimetric materials, as polymer gels. They are largely employed in radiotherapy dosimetry to mimic human tissue. New polymer gels were studied in order to better represent different organs or tissues, to provide more reliable results, or even to use different measurement techniques. The objective of this study was to evaluate the dosimetric properties of polymer gels, in relation to its mass-energy absorption coefficients, energy response and tissue equivalence. For this purpose the MCNPX Monte Carlo code was utilized. Three different materials, employed in radiotherapy dosimetry were evaluated in this work: MAGAS, MAGAT and AMPS. For all simulations carried out, the values were within an acceptable uncertainty and in accordance to the expected results.

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  • IPEN-DOC 27209

    CASTRO, MAYSA C. ; SILVA, NATALIA F. ; SANTOS, LUCAS R.; CINTRA, FELIPE B. ; CALDAS, LINDA V.E. . Evaluation of an extrapolation chamber for dosimetry in computed tomography beams using Monte Carlo code (MCNP5). Radiation Physics and Chemistry, v. 167, p. 1-4, 2020. DOI: 10.1016/j.radphyschem.2019.04.043

    Abstract: Computed tomography (CT) is responsible for the highest dose values to the patients during the exams. Therefore, the radiation doses in this procedure must be accurate. However, there is no primary standard system for this kind of radiation beam yet. A homemade extrapolation ionization chamber was preliminary evaluated for the establishment of a CT beam primary standard. The aim of this study was to determine the influence that the various components of the extrapolation chamber may present on the energy deposited in its sensitive volume. Different materials for its collecting electrode were also studied for this type of radiation beam. The evaluation of the homemade extrapolation chamber showed the highest influence of 25.9% for the collecting electrode, and the best material for the collecting electrode for CT radiation beams was graphite.

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  • IPEN-DOC 27208

    ASSEMANY, LADYJANE P.F. ; RODRIGUES JUNIOR, ORLANDO ; SILVA, EZEQUIEL da ; POTIENS, MARIA da P.A. . Evaluation of 3D printing filaments for construction of a pediatric phantom for dosimetry in CBCT. Radiation Physics and Chemistry, v. 167, p. 1-4, 2020. DOI: 10.1016/j.radphyschem.2019.03.031

    Abstract: Cone-beam computed tomography (CBCT) has been widely used in orthodontics, due to the ability to provide visualization of mineralized tissues in high definition and consequently the identification and delimitation of three-dimensional irregularities. Compared with 2D imaging techniques, the doses used in CBCT exams are higher. Considering that the pediatric and adolescent population routinely receives orthodontic treatments, it is important to note that the cellular development phase of the organs is associated with increased tissue sensitivity to radiation, and that cancer is one of the main long-term effects caused by exposure to X radiation. In recent years, the 3D printing technique has been used in the medical industry because it allows the reproduction of structures of the human body, enabling detailed studies in several application areas. The objective of this work was to study the different types of filaments available for 3D printing of structures that will compose a phantom for dose evaluation in the pediatric and adolescent population who undergo CBCT exams.

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  • IPEN-DOC 27207

    CASSARES, MARCELLA; SAKOTANI, NATALIA L.; KUNIGK, LEO; VASQUEZ, PABLO A.S. ; JURKIEWICZ, CYNTHIA. Effect of gamma irradiation on shelf life extension of fresh pasta. Radiation Physics and Chemistry, v. 174, p. 1-8, 2020. DOI: 10.1016/j.radphyschem.2020.108940

    Abstract: The feasibility of extending shelf life of fresh pasta using gamma radiation was evaluated. Microbiological quality and technological and sensorial properties were determined. Commercial gnocchi without chemical preservative was irradiated at doses of 5, 10 and 13 kGy and stored at 7, 15 and 25 °C during 90 days. The 13 kGy dose was effective in reducing the microbial count below the detection limit during storage at 25 °C. The growth of surviving psychrotrophic and mesophilic bacteria and molds and yeasts in pasta irradiated at 5 and 10 kGy was fitted to modified Gompertz and logistic models and kinetic parameters were determined. The gamma radiation did not change the cooking loss but reduced significantly the water absorption. There was no significant difference in the overall impression between control and irradiated samples. Gamma irradiation technology has a great potential to preserve fresh pasta at room temperature for more than 90 days without compromising sensory properties.

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  • IPEN-DOC 27206

    VILLANI, D. ; RODRIGUES JUNIOR, O. ; CAMPOS, L.L. . Dosimetric characterization of 3D printed phantoms at different infill percentages for diagnostic X-ray energy range. Radiation Physics and Chemistry, v. 172, p. 1-6, 2020. DOI: 10.1016/j.radphyschem.2020.108728

    Abstract: The aim of this paper is to characterize 3D printed phantoms and printing set-ups with different infill percentages for imaging energy X-ray beams attenuation. 3D printing performance was studied using the fused filament fabrication (FFF) technique with PLA (Polylactic Acid) and ABS (Acrylonitrile Butadiene Styrene) filaments. Phantom plates were printed and, using the Pantak Seifert X-ray system with different beam qualities in the diagnostic range, the attenuation coefficients were obtained experimentally with the transmission method and results compared with PMMA used as reference and theoretical data. Different percentages of infill of printed phantoms were also evaluated and transmission characterized. The attenuation coefficients were determined for the different beam qualities and results show that the variation in the values of attenuation coefficients decreases as the infill quality increases. Attenuation characteristics evaluated indicates the suitable equivalence of PLA to PMMA for 3D printing water/tissue equivalent most complex geometry phantoms. The different printing modes characterized together with their attenuation coefficients for the X-ray beams will be studied and used in the development of new 3D printed phantoms in our institute.

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  • IPEN-DOC 27205

    GROPPO, DANIELA P. ; SARAIVA, CRYSTIAN W.C.; CALDAS, LINDA V.E. . Determination of the penumbra width of Elekta SRS cone collimator for 6 MV FF and 6 MV FFF energies using gradient-based edge detection. Radiation Physics and Chemistry, v. 167, p. 1-5, 2020. DOI: 10.1016/j.radphyschem.2019.05.009

    Abstract: The dosimetric measurements of small fields of radiation are undertaken with detectors such as: GafchromicTM films, diodes, diamond detectors and ionization chambers of small volumes. The penumbra width, e.g. the spatial distance between 80% and 20% dose, is smaller in small fields. This fact increases the curvature and hence the volume effect in the penumbra region. The accuracy in the penumbra calculation is important at the QA test for implementation of the cranial Stereotactic Radiosurgery. The objective of this work was to apply a Gradient- Based Edge Detection plugin to calculate the penumbra of a radiation beam defined with the Elekta SRS Cone Collimators for beams of 6 MV (Flattening Filter – FF) and 6 MV (Flattening Filter Free – FFF) energies using the beam profile obtained with GafchromicTM film. The results corroborate those from the literature, and they allow a quantitative evaluation of the width of dosimetric penumbra by Gradient-Based Edge Detection.

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  • IPEN-DOC 27204

    GONCALVES, JOSEMARY A.C. ; MANGIAROTTI, ALESSIO; BUENO, CARMEN C. . Current response stability of a commercial PIN photodiode for low dose radiation processing applications. Radiation Physics and Chemistry, v. 167, p. 1-4, 2020. DOI: 10.1016/j.radphyschem.2019.04.026

    Abstract: This work investigates the on-line response of a thin diode, for monitoring low dose radiation processing, with respect to the linearity between current and dose-rate, the most interesting part being the variation of the current sensitivity with the accumulated dose. The results obtained indicate that the current response of this diode is linear and quite stable with repeatability better than 0.2% and a slight decay of 5% of the current sensitivity (0.28 nA h/Gy) for doses up to 15 kGy. In an attempt to give theoretical support to these results, the radiation induced current is calculated as a function of the dose rate assuming the diode to be thin as compared with the standard values of the minority carrier diffusion lengths in intrinsic silicon. Agreement within 2% is found between calculations and experimental data.

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  • IPEN-DOC 27203

    ALVARENGA, TALLYSON S. ; POLO, IVON O. ; PEREIRA, WALSAN W.; SILVA, FELIPE S.; FONSECA, EVALDO S.; CALDAS, LINDA V.E. . Contribution of the scattered radiation on the neutron beam fluence at the calibration laboratory of IPEN. Radiation Physics and Chemistry, v. 167, p. 1-5, 2020. DOI: 10.1016/j.radphyschem.2019.03.023

    Abstract: In recent years, an upsurge in demand for neutron calibrations has been experienced in Brazil and several other countries in Latin America, mainly due to the increase in oil prospection and extraction procedures. The only laboratory for calibration of neutron detectors in Brazil is located at the Institute for Radioprotection and Dosimetry (IRD/CNEN), Rio de Janeiro. This laboratory is the national standard dosimetry laboratory in Brazil. With the increase in the demand for the calibration of neutron detectors, the need for more calibration services became evident. In this context, the Calibration Laboratory of IPEN/CNEN, São Paulo, which already offers calibration services of radiation detectors with standard X, gamma, beta and alpha beams, recently projected a new calibration laboratory for neutron detectors. One of the main problems in this kind of calibration laboratory is related to the knowledge of scattered radiation. In order to evaluate it, simulations were performed without the presence of the structural elements and with the complete room. Thirteen measurement points were evaluated at various distances. As part of the characterization process of the radiation fields of the new Neutron Calibration Laboratory, this work presents results on the influence of the radiation scattered by the structural components of the room: walls, doors, ceiling and floor, in different calibration positions, on the detector response. Therefore, the neutron radiation attenuation and the scattering parameters were determined at different source-detector distances, through computational simulation, using the MCNP5 Monte Carlo code.

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  • IPEN-DOC 27202

    NEVES, LUCIO P.; FRANCO, ADRIANE B.; FRANÇA, MONIQUE; SOARES, MARIA R.; BELINATO, WALMIR; SANTOS, WILLIAM S. ; CALDAS, LINDA V.E. ; PERINI, ANA P.. Computational dosimetry in a pediatric i-CAT procedure using virtual anthropomorphic phantoms. Radiation Physics and Chemistry, v. 167, p. 1-5, 2020. DOI: 10.1016/j.radphyschem.2019.03.040

    Abstract: The craniofacial structure is three-dimensional, and for a better visualization of these structures, Computed Tomography is often employed for diagnoses, even though being a high-cost procedure, leading to increased exposure to ionizing radiation. As a consequence, studies in dosimetry are necessary, since several radiosensitive structures are located in the head and neck, such as thyroid, crystalline and salivary glands. There is an overall consensus regarding the exposure of pediatric patients to ionizing radiation, with recommendations being that the procedures must occur with the shortest exposure time as possible, and it is only prescribed when they are effectively necessary. During the procedures, radiation effects are difficult to be measured. The use of either TL or OSL dosimeters can create artifacts within the images, and the positioning of a large number of dosimeters, necessary for the correct dose evaluation, is not feasible when it comes to a pediatric patient. Therefore pediatric virtual anthropomorphic phantoms and Monte Carlo simulations were used in this work. The absorbed and effective doses were determined during an i-CAT procedure, with 5 different fields of view, utilizing 5- and 10- year-old male virtual anthropomorphic phantoms. The results pointed out that the eye lens, salivary glands and thyroid received the highest doses. Besides, the effective dose values increase with the increasing of the FOV size, and the 5-year-old male virtual anthropomorphic phantom presented the highest effective dose values.

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  • IPEN-DOC 27201

    FREITAS, LUCAS F. de ; CRUZ, CASSIA P.C. da; CAVALCANTE, ADRIANA K. ; BATISTA, JORGE G. dos S. ; VARCA, GUSTAVO H.C. ; MATHOR, MONICA B. ; LUGAO, ADEMAR B. . Comparison between gold nanoparticles synthesized by radiolysis and by EGCG-driven gold reduction. Radiation Physics and Chemistry, v. 174, p. 1-9, 2020. DOI: 10.1016/j.radphyschem.2020.108959

    Abstract: Radiolytic synthesis and phytochemical-driven gold reduction for the generation of nanoparticles are successful examples of Green Chemistry applied for nanomaterials. The present work compares these two green approaches focusing on hydrodynamic size, stability over time, optical properties and toxicity in NIH 3T3 (ATCC® CRL- 1658™) cells and Danio rerio (Zebra Fish). The radiolytic synthesis was performed by mixing 1 mM NaAuCl4; polyvinyl pyrrolidone 0.5%, AgNO3 6×10−5 M, propan-2-ol 0.2 M and acetone 0.06 M, followed by irradiation at 15 kGy (5 kGy h−1, 60Co source). The EGCG-functionalized nanoparticles were synthesized by mixing 1.6 mM of Au with 0.8 mM of EGCG in phosphate buffer (10 mM) for 2 h. Both methods yield the formation of gold nanoparticles featuring plasmon resonance bands at 520–530 nm, polydispersity above 0.3 was relevant only for the radiolytic protocol. Regarding stability over time, after 30 days, the nanoparticles synthesized radiolytically presented no relevant size changes, while some aggregation was observed for the EGCG-particles. The same nanoparticles demonstrated a lack of stability in high ionic strength medium. Slight toxicity was observed for the EGCG-nanoparticles in Danio rerio, with an IC50 calculated as 40.49%, while no IC50 was established within the concentration range of radiolysis-AuNPs used in this study. In conclusion, both green methods generated nanoparticles with good control of size and optical properties, especially via reduction by EGCG. However, the stability and toxicity results were found to be more promising for the radiolytically synthesized gold nanoparticles.

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  • IPEN-DOC 27200

    ALMEIDA, S.B. ; VILLANI, D. ; SAKURABA, R.K.; REZENDE, A.C.P.; CAMPOS, L.L. . Comparison between Al2O3:C pellets and DIODEs for TSEB in vivo dosimetry using an anthropomorphic phantom. Radiation Physics and Chemistry, v. 167, p. 1-4, 2020. DOI: 10.1016/j.radphyschem.2019.02.030

    Abstract: The Total Skin Electron Beam (TSEB) therapy is a technique that aims to provide skin surface homogeneous absorbed dose in order to treat cutaneous T-cell lymphomas, both for curative and palliative purposes with electron beams penetrating a few millimeters into the skin, reaching the affected parts without affecting internal organs. In vivo dosimetry has become an important role for the treatment of total skin irradiation within a rigorous quality assurance. The luminescent dosimeters, such as TLDs and OSLDs, have proven to be very useful for the verification of the dose distribution and prescribed for the patient as the dose may differ from place to place due to patient body geometry, overlapping of structures and asymmetries of the radiation field. Other routine in vivo dosimetry tool is the DIODEs and they as well help validating radiation therapy dosimetry. Al2O3:C OSL pellets manufactured and marketed by REXON Components and TLD Systems have already been characterized for TSEB applications. The aim of this work is to compare the performance of Al2O3:C OSL pellets from REXON to in vivo TSEB dosimetry with silicon DIODEs QEDTM detectors from Sun Nuclear (EUA) using an anthropometric phantom. Dosimeters and DIODEs were previously characterized for 6 MeV HDTSe- electron beams and then placed over an Anderson Rando® anthropomorphic phantom, evaluating the body dose distribution. The reference point of measurement was the umbiculous as recommended by formalism. The results showed that the Al2O3:C OSL pellets presented acceptable results, but some greater variation of the response in relation to silicon DIODEs were found due to its considerable rotational dependency.

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  • IPEN-DOC 27199

    NASCIMENTO, BRUNA C.; FRIMAIO, AUDREW ; BARRIO, RAMON M.M.; SIRICO, ANA C.A.; COSTA, PAULO R.. Comparative analysis of the transmission properties of tissue equivalent materials. Radiation Physics and Chemistry, v. 167, p. 1-7, 2020. DOI: 10.1016/j.radphyschem.2019.04.050

    Abstract: Phantom objects have as main requirement to have the effective atomic number and linear attenuation coefficient approximately equal to the human tissue to be simulated. The present work aims to characterize samples of materials radiologically equivalent to water for dose studies in patients in the diagnostic energy range. Water was chosen as reference material representing human tissue, which is composed mostly of it. A set of samples was formulated and submitted to radiation transmission tests in four different values of tension applied to an Xray tube. Mass densities of the samples were evaluated using the Arquimedes method. The samples were identified as A, B, C and D. By transmission curves, it was possible to estimate the samples transmission factors corresponding to the water transmission factor for different thicknesses. Moreover, the thicknesses of samples equivalent to water thickness for different values of transmission factor were also evaluated. All the samples densities were bigger than the density of water. For the same thickness of water and the samples, the radiation transmission of the developed materials are in better agreement for thicknesses of 10mm and 30 mm. The lowest percentage difference between the water transmission and the transmission of any of the samples obtained was approximately 0.6% for the sample A in the thickness of 30mm under voltage of 60 kV. The correspondence between the transmission factors and the thicknesses showed that the compounds studied in this work are potential materials to develop phantoms that simulate the transmission properties of human tissue.

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  • IPEN-DOC 27198

    SAVI, MATHEUS ; ANDRADE, MARCO A.B.; POTIENS, MARIA P.A. . Commercial filament testing for use in 3D printed phantoms. Radiation Physics and Chemistry, v. 174, p. 1-7, 2020. DOI: 10.1016/j.radphyschem.2020.108906

    Abstract: There is a great demand for phantoms by many areas of knowledge to be used for teaching or daily work. However, commercial phantoms are expensive and hard to obtain, especially in countries going through development. As an alternative, 3D printing can be the way to produce less expensive and reliable 3D phantoms. The goal of this study is to evaluate 14 available commercial filaments, in order to find if and how they can be used in 3D printed phantoms in computed tomography. Each material was printed as a 2 cm edge cube with rectilinear pattern and 60, 80 and 100% infill. The 80% infill of five other patterns were also printed and compared. Each 100% infill cube was weighted and had its density calculated. After that, the cubes were scanned in a Philips CT Brilliance 6 with 120 kVp, 200 mA, 2 mm slices and standard reconstruction. At the center of each cube, a ~120 mm2 region of interest was set to measure the mean Hounsfield Unit (HU) and its standard deviation. The software Origin was used to plot HU results for rectilinear pattern, determine linear trends with its R2 and compare achieved values with HU tissue range from literature. To confirm the response of HU values of selected tested materials in CT imaging as a function of percentage infill, a phantom prototype of a finger was 3D printed. The HU of the tested materials ranged from −516.2 ± 7.3 to 329.8 ± 18.9. All human tissues could be mimicked making use of these materials, except cortical bone above ~350 HU and tooth parts. The most promising filament was PLA + Cu, due to the multiple infill configuration that allows the resulting HU range to represent from adipose and skin tissue to marrow bone.

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  • IPEN-DOC 27197

    POLO, IVON O. ; SANTOS, WILLIAM S. ; CALDAS, LINDA V.E. . Characterization of an extrapolation chamber in beta radiation beams and Monte Carlo modelling. Radiation Physics and Chemistry, v. 171, p. 1-9, 2020. DOI: 10.1016/j.radphyschem.2020.108746

    Abstract: At the Calibration Laboratory (LCI) of the IPEN/CNEN, studies are in development on the establishment of a standard composed by the beta radiation sources for the dosimetry and calibration for personal monitoring in Brazil. For this purpose is used the Böhm extrapolation chamber (PTW model 23392). This chamber was already characterized at LCI in 90Sr/90Y beams using two different entrance windows: one of aluminized Mylar and another of PET (polyethylene terephthalate) known as Hostaphan. In this work, this extrapolation chamber was characterized in 85Kr and 147Pm beams. All tests were carried out with the reference 90Sr /90Y source, for comparison purposes. The Monte Carlo code MCNP5 code was used to obtain an extrapolation chamber and the BSS2 system sources computational model, based on the determination of the absorbed dose rate. Saturation curves, ion collection efficiency, ion recombination, polarity effect, stability of response, null depth, linearity of response, variation of response as a function of source-detector distance, extrapolation curves, correction factors and absorbed dose rates were obtained. The difference between the experimental absorbed dose rates and those obtained using the Monte Carlo model, compared to those from the calibration certificates, was less than 1.9% for the 108 histories for each BSS2 system source. All results of the performed tests are within the limits of the international recommendations. The results for the 90Sr/90Y source were in good agreement with previous works performed at LCI. These results are suitable for the establishment of a standard instrument for the dosimetry and calibration of beta radiation sources and detectors in the LCI/IPEN. This standard will allow the calibration of detectors in beta radiation beams in dosimetry services in Brazil.

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  • IPEN-DOC 27196

    JUNOT, DANILO O. ; SOUZA, DIVANIZIA N.; CALDAS, LINDA V.E. . TL/OSL signal of CaSO4:Eu,Ag samples produced by variations of the slow evaporation route. Radiation Measurements, v. 135, p. 1-8, 2020. DOI: 10.1016/j.radmeas.2020.106334

    Abstract: The aim of this work was to produce crystals of CaSO4 doped with europium (Eu) and silver (Ag) nanoparticles, by means of three different preparation routes, and to study their applicability in radiation dosimetry by the TL and OSL techniques. The crystals were produced by variations of the slow evaporation route. Samples of CaSO4: Eu,Ag(a) were obtained using europium oxide and silver particles as dopants. For the growth of the crystals of CaSO4:Eu,Ag(b), silver was incorporated in nitrate form. CaSO4:Eu,Ag(c) phosphorus were synthetized mixing europium oxide in a colloidal suspension of silver nanoparticles. Optical characterization confirmed the presence of Eu3þ/Eu2þ in the crystal matrix. Dosimetric characteristics were evaluated after the exposure of the samples to a90Sr/90Y source. The CaSO4:Eu,Ag(a) and CaSO4:Eu,Ag(b) composites presented the most intense signals, the lowest detectable doses, and showed a linear and reproducible dose response, but the CaSO4:Eu,Ag(a) samples showed the best potential for application in TL/OSL dosimetry.

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  • IPEN-DOC 27195

    GUEDES-SILVA, CECILIA C. ; RODAS, ANDREA C.D.; CARVALHO, FLAVIO M.S.; HIGA, OLGA Z. ; FERREIRA, THIAGO S. . Silicon nitride with titania, calcia and silica additives for orthopaedic applications. Processing and Application of Ceramics, v. 14, n. 1, p. 63-70, 2020. DOI: 10.2298/PAC2001063G

    Abstract: Titanium, silicon and calcium ions have demonstrated positive effects in bone healing. Therefore, this paper investigates the densification, mechanical properties and in vitro biological behaviour of TiO2, together with SiO2 and CaO, on silicon nitride ceramics to be used in clinical applications. The results revealed that the sintered samples reached high values of relative density and fracture toughness, non-cytotoxicity as well as good ability to promote cell proliferation and form a layer of carbonated hydroxyapatite on their surfaces, after immersion in simulated body fluid. The sample with the highest amount of TiO2 reached the highest value of relative density and the best results of cell proliferation and fracture toughness, indicating the great potential to be explored by in vivo experiments for later application as intervertebral devices.

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  • IPEN-DOC 27194

    BELLINI, MARIA H. ; SOUZA, ALEXANDRE L. de ; SILVA, FABIO F. da; GUILHEN, SABINE N. ; FERREIRA, RAFAEL V. de P.; ARAUJO, LEANDRO G. de ; OLIVEIRA, JOAO E. de ; MARUMO, JULIO T. . Variations in essential elements after malignant transformation of kidney epithelial tubular cells. Medical & Clinical Research, v. 5, n. 6, p. 114-117, 2020. DOI: 10.33140/MCR.05.06.04

    Abstract: Cell line-based research is a valuable tool for the study of cancer physiopathology and the discovery of new drugs for use in clinical practice. In this study, inductively coupled plasma mass spectrometry (ICP-MS) was used to estimate Ca, Co, Cu, Fe, K, Mg, Mn, Na, P, S, Se, and Zn in epithelial tubular cells (HK-2) and kidney tumor cells (Caki-1 cells). The most relevant difference was a decrease in the contents of Ca, Cu, Fe, K, Mg, Mn, Na, P, S, and Zn. A significant accumulation of Co was also detected in Caki-1 cells. The fold change variation of each element concentration between HK-2 and Caki-1 cells was Ca (‒0.40), Co (1.37), Cu (‒0.68), Fe (‒0.56), K (‒0.40), Mg (‒0.41), Mn (-0.54), Na (‒0.33), P (‒0.31), S (‒0.26), and Zn (‒0.73). These findings indicate that the elements mainly affect the metabolic pathways of epithelial kidney cells. Thus, our findings open a new avenue for RCC target therapy

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  • IPEN-DOC 27193

    SILVA, JAQUELINE S. da ; CARVALHO, SABRINA G.M. ; SILVA, RODRIGO P. da ; TAVARES, ANA C.; SCHADE, ULRICH; PUSKAR, LJILJANA; FONSECA, FABIO C. ; MATOS, BRUNO R. . SAXS signature of the lamellar ordering of ionic domains of perfluorinated sulfonic-acid ionomers by electric and magnetic field-assisted casting. Physical Chemistry Chemical Physics, v. 22, n. 24, p. 13764-13779, 2020. DOI: 10.1039/d0cp01864c

    Abstract: At present, small angle X-ray scattering (SAXS) studies of perfluorinated sulfonic-acid ionomers (PFSAs) are unable to fully determine the true shape of their building blocks, as recent SAXS modelling predicts disk- and rod-like nanoionic domains as being equally possible. This scenario requires evidence-based findings to unravel the real shape of PFSA building blocks. Herein, a SAXS pattern signature for a lamellar nanophase separation of the ionic domains of Nafion is presented, backed by mid and far infrared spectroscopy (MIR and FIR) and wide angle X-ray scattering (WAXS) data of Nafion in different ionic forms, a broad range of ionic phase contents (EW ~ 859–42 252 g eq-1) and temperatures. The study indicates that the lamellar arrangement of the ionic domains is the most representative morphology that accounts for the physical properties of this ionomer. The lamellar SAXS reflections of Nafion are enhanced in electric and magnetic field-aligned membranes, as confirmed by atomic force microscopy (AFM). Electric and magnetic field-assisted casting of Nafion allowed producing nanostructured and anisotropic films with the lamellas stacked perpendicularly to the field vector, which is the direction of interest for several applications. Such nanostructured Nafion membranes are bestowed with advanced optical and proton transport properties, making them promising materials for solar and fuel cells.

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  • IPEN-DOC 27192

    NISTI, M.B. ; MADUAR, M.F. ; SAUEIA, C.H.R. ; CAVALCANTE, F. ; MAZZILLI, B.P. . Optimization of the gamma-ray spectrometry counting time based on uncertainties of radionuclides concentration in samples. Brazilian Journal of Radiation Sciences, v. 8, n. 2, p. 1-12, 2020. DOI: 10.15392/bjrs.v8i2.1197

    Abstract: This paper aims to propose an easy and fast method of optimization of the gamma-ray spectrometry counting time in determining natural radionuclides (210Pb, 212Pb, 214Pb, 212Bi, 214Bi and 228Ac) in order to minimize uncertainties in the concentration. The samples were measured by gamma-ray spectrometry with a hyper-pure germanium detector Canberra, 25% relative efficiency, effective resolution of 1.9 keV on the 1332.5 keV 60Co with associated electronics and coupled to a microcomputer. Multichannel Maestro A65-I model was used for spectrum acquisition and peak net area determination, and WinnerGamma/Interwinner 6.01 software was used for gamma-ray spectra analysis and to calculate the concentrations and associated uncertainties. The counting times used were 86,000 s and 150,000 s.

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  • IPEN-DOC 27191

    REDÍGOLO, M.M. ; ALVES, M.V.R.; REIS, T.R. dos; CARNEIRO, T.C.; COSTA, I. ; BUSTILLOS, O.V. . Material characterization of exudates from Brazilian contemporary oil painting by FTIR, Py-GC/MS and SEM-EDS. Asian Journal of Science and Technology, v. 11, n. 4, p. 10880-10882, 2020.

    Abstract: Contemporary art has employed almost every single synthetic material created by man. Nonetheless, the appeal of oil paint is still present at most public and private collections. Oil paint manufacture has evolved over time along with its formulation and conservation concerns. A reported problem is the formation of exudates on contemporary oil paintings. This work aims to characterize exudates from the Brazilian oil painting “Três pessoas” (1999), by Marina Saleme. Characterization was carried out by Fourier transform infrared spectroscopy, pyrolysis coupled to gas chromatography and mass spectrometry and scanning electron microscopy coupled to energy dispersive x-ray fluorescence spectrometry. Results indicate that exudates are formed by the oxidation of linseed oil and formation of dicarboxylic acids. This process is aided by the formation of zinc stearate in the paint film.

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  • IPEN-DOC 27190

    BELLINI, MARIA H. ; SOUZA, ALEXANDRE L. de ; SILVA, FABIO F. da; GUILHEN, SABINE N. ; FERREIRA, RAFAEL V. de P.; OLIVEIRA, JOAO E. de ; MARUMO, JULIO T. . Essential elements as biomarkers of metastatic renal cell carcinoma. Medical & Clinical Research, v. 5, n. 7, p. 143-146, 2020. DOI: 10.33140/MCR.05.07.04

    Abstract: Renal cell carcinoma (RCC) represents 3% of human malignant tumors and approximately 90% of malignant renal neoplasms. Despite great therapeutic advances in the last decade, metastatic RCC (mRCC) is still considered an incurable disease. In this study, we examined the potential of essential elements as biomarkers of mRCC using an orthotropic metastatic mouse model. Frozen lung and plasma samples from healthy and mRCC-induced mice were lyophilized, digested, and analyzed using inductively coupled plasma mass spectrometry. In metastatic lungs, a significant increase in Ca concentration (268%) was observed, whereas a significant decrease in Cu (23.2%), Fe (17.4%), Mn (38.8%), and Na (11.7%) was observed. The plasma of mRCC-induced mice showed decreased concentrations of Mn (53%), Na (19.7%) and Zn (49,50%) and increased levels of Ca (53%), Cu (39.5%), Our findings revealed marked differences in the concentrations of essential elements in the lung and plasma of the metastatic mouse model. The circulating levels of Ca, Cu, Mn, Na, and Zn could be utilized as diagnostic and therapeutic response biomarkers.

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  • IPEN-DOC 27189

    BELLINI, MARIA H. ; JORGE, AMANDA S.; MARUMO, MATHEO B.; OLIVEIRA, SORAIA B. de. Descriptive epidemiological and pathological study of canine renal cell carcinoma. Journal of Veterinary Science & Medical Diagnosis, v. 9, n. 3, p. 1-4, 2020.

    Abstract: Renal cell carcinoma (RCC) accounts for 0.5–1.5% of all canine tumor types and is very aggressive, rapidly growing, and metastasis-generating, culminating in the death of the animal. The management of canine RCC lacks predictive biomarkers. The aim of this study is to conduct an epidemiological and pathological analysis of dogs affected with RCC.A retrospective and descriptive review of studies published between January 2001 to December 2019 was carried out using the following electronic databases: Web of Science, PubMed, SciELO, Science Direct. Twenty-one articles from 11 countries were included in the study, totaling 258 cases. Histopathological analysis based on cytological criteria showed that cromophobic and clear cell carcinoma were the most frequent subtypes. The histological classification revealed that papillary and tubular carcinoma accounted for 70% of the cases. Vimentin, Pax8, CKs (CK AE1/AE3, CK CAM5.2 and CK7), COX-2, Napsin-A, CD10 and CD117 were the most commonly used diagnostic biomarkers, corresponding to 80% of cases. Moreover, 14-3-3σ and COX-2 were also used as predictive biomarkers for canine RCC. In conclusionVimentin, Pax8, CKs (CK AE1/AE3, CK CAM5.2 and CK7), COX-2, Napsin-A, CD10 and CD117 were the most commonly used diagnostic biomarkers, corresponding to 80% of cases. Moreover, 14-3-3σ and COX-2 were also used as a predictive biomarker for canine RCC.

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  • IPEN-DOC 27188

    SOARES, ROSANE B.; COSTA, DENIS H.; MIYAKAWA, WALTER; DELGADO, MARIA G.T.; GARCEZ, AGUINALDO S.; YOSHIMURA, TANIA M. ; RIBEIRO, MARTHA S. ; NUNEZ, SILVIA C.. Photodynamic activity on biofilm in endotracheal tubes of patients admitted to an intensive care unit. Photochemistry and Photobiology, v. 96, n. 3, SI, p. 618-624, 2020. DOI: 10.1111/php.13239

    Abstract: Ventilator-associated pneumonia (VAP) is an infection that arises after endotracheal intubation affecting patients under intensive care. The presence of the endotracheal tube (ETT) is a risk factor since it is colonized by multispecies biofilm. Antimicrobial photodynamic therapy (aPDT) could be a strategy to decontaminate ETTs. We verify if methylene blue (MB) associated with external illumination of the ETT could be an alternative to destroy biofilm. We performed an in vitro and ex vivo study. In vitro study was performed with P. aeruginosa biofilm grew over ETT for 7 days. After treatment, the surviving cells were cultured for 3 days and the biofilm was analyzed by crystal violet absorbance. Ex vivo study employed ETT obtained from extubated patients. aPDT was performed with MB (100 μM) and red LED (k = 640±20 nm). We quantified the biofilm thickness and used scanning electron microscopy and fluorescence technique to verify morphological and functional changes after aPDT. Our results showed that bacteria remain susceptible to aPDT after sequential treatments. We also attested that aPDT can reduce biofilm thickness, disrupt biofilm attachment from ETT surface and kill microbial cells. These data suggest that aPDT should be investigated to decrease VAP incidence via ETT decontamination.

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  • IPEN-DOC 27187

    QUIRINO, THATYANE de C.; ORTOLAN, LUANA dos S.; SERCUNDES, MICHELLE K.; MARINHO, CLAUDIO R.F.; TURATO, WALTER M.; EPIPHANIO, SABRINA. Lung aeration in experimental malaria-associated acute respiratory distress syndrome by SPECT/CT analysis. PLoS One, v. 15, n. 5, p. 1-18, 2020. DOI: 10.1371/journal.pone.0233864

    Abstract: Malaria-associated acute respiratory distress syndrome (ARDS) is an inflammatory disease causing alveolar-pulmonary barrier lesion and increased vascular permeability characterized by severe hypoxemia. Computed tomography (CT), among other imaging techniques, allows the morphological and quantitative identification of lung lesions during ARDS. This study aims to identify the onset of malaria-associated ARDS development in an experimental model by imaging diagnosis. Our results demonstrated that ARDS-developing mice presented decreased gaseous exchange and pulmonary insufficiency, as shown by the SPECT/CT technique. The pulmonary aeration disturbance in ARDS-developing mice on the 5th day post infection was characterized by aerated tissues decrease and nonaerated tissue accumulation, demonstrating increased vascular permeability and pleural effusion. The SPECT/CT technique allowed the early diagnosis in the experimental model, as well as the identification of the pulmonary aeration. Notwithstanding, despite the fact that this study contributes to better understand lung lesions during malaria-associated ARDS, further imaging studies are needed.

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  • IPEN-DOC 27186

    SCHELL, J.; DANG, T.T.; ZYABKIN, D.V.; MANSANO, R.D.; GAERTNER, D.; CARBONARI, A.W. . Investigation of the local environment of SnO2 in an applied magnetic field. Physica B: Physics of Condensed Matter, v. 586, p. 1-6, 2020. DOI: 10.1016/j.physb.2020.412120

    Abstract: This paper presents the results of time-differential perturbed gamma–gamma angular correlation measurements of SnO2 thin films carried out in an applied magnetic field. The measurements were performed upon the implantation of Fe at 80 keV and 111In (111Cd) at 160 keV. The samples were further characterized by energydispersive X-ray spectroscopy. The hyperfine parameters were studied at room temperature with and without an applied magnetic field. The results indicate the presence of two distinct local environments for the probe nuclei. Both occupy a paramagnetic state and correspond to a substitutional Sn site in the rutile phase of SnO2 with different numbers of electrons added to SnO2:Cd0. In addition, the crystal homogeneity of the site 1 increases upon applying the magnetic field.

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  • IPEN-DOC 27184

    PAGGIARO, ANDRÉ O.; MATHOR, MONICA B. ; TEODORO, WALCY R.; ISAAC, CESÁR; CAPELOZZI, VERA L.; GEMPERLI, ROLF. Evaluation of radiosterilized glyercerolated amniotic membranes as a substrate for cultured human epithelial cells. Organogenesis, v. 16, n. 1, p. 27-41, 2020. DOI: 10.1080/15476278.2020.1723366

    Abstract: Human amniotic membrane (HAM) is a biomaterial with biological properties beneficial to tissue repair, serving as a substrate for cell cultivation. Irradiation is used for tissue sterilization, but can damage the HAM structure. The objective of this paper was to construct a skin substitute, composed of human keratinocytes cultured on glycerolated HAMs, and to evaluate the influence radiation on subsequent cell culture growth. Four batches of HAMs were glycerolated, and half of them were radio-sterilzed with 25 kGy. Non-irradiated glycerolated HAM (ni-HAM) and irradiated glycerolated HAM (i-HAM) samples were then de-epithelized and analyzed using optical microscopy (Picrossirius staining), immunofluorescence and electron microscopy. Subsequently, keratinocytes were cultured on ni- and i-HAMs, and either immersed or positioned at the air-liquid interface. The basement membranes of the ni-HAM group remained intact following de-epithelialization, whereas the i-HAM group displayed no evidence or remnant presence of these membranes. Concerning the keratinocyte cultures, the ni-HAM substrate promoted the growth of multi-layered and differentiated epithelia. Keratinocytes cultured on i-HAM formed epithelium composed of three layers of stratification and discrete cell differentiation. The glycerolated HAM was compatible with cultured epithelia, demonstrating its potential as a skin substitute. Irradiation at 25 kGy caused structural damage to the amnion.

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  • IPEN-DOC 27183

    MAPRELIAN, EDUARDO ; TORRES, WALMIR M. ; BELCHIOR JUNIOR, ANTONIO ; UMBEHAUN, PEDRO E. ; BERRETTA, JOSE R. ; SABUNDJIAN, GAIANE . Total and partial loss of coolant experiments in an instrumented fuel assembly of IEA-R1 research reactor. Nuclear Engineering and Design, v. 363, p. 1-11, 2020. DOI: 10.1016/j.nucengdes.2020.110610

    Abstract: The safety of nuclear facilities has been a growing global concern, mainly after the Fukushima nuclear accident. Studies on nuclear research reactor accidents such as the Loss of Coolant Accident (LOCA), many times considered a design basis accident, are important for ensure the integrity of the plant. A LOCA may lead to the partial or complete uncovering of the fuel assemblies and it is necessary to assure the decay heat removal as a safety condition. This work aimed to perform, in a safe way, partial and complete uncovering experiments for an Instrumented Fuel Assembly (IFA), in order to measure and compare the actual fuel temperatures behavior for LOCA in similar conditions to research reactors. A test section for experimental simulation of Loss of Coolant Accident named STAR was designed and built. The IFA was irradiated in the IEA-R1 core and positioned in the STAR, which was totally immersed in the reactor pool. Thermocouples were installed in the IFA to measure the clad and fluid temperatures in several axial and radial positions. Experiments were carried out for five levels of uncovering of IFA, being one complete uncovering and four partial uncovering, in two different conditions of decay heat. It was observed that the cases of complete uncovering of the IFA were the most critical ones, that is, those cases presented higher clad temperatures when compared with partial uncovering cases, for the specific conditions of heat decay intensity and dissipation analyzed. The maximum temperatures reached in all experiments were quite below the fuel blister temperature, which is around 500 °C. The STAR has proven to be a safe and reliable experimental apparatus for conducting loss of coolant experiments.

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  • IPEN-DOC 27182

    WASINSKI, FREDERICK; FURIGO, ISADORA C.; TEIXEIRA, PRYSCILA D.S.; RAMOS-LOBO, ANGELA M.; PERONI, CIBELE N. ; BARTOLINI, PAOLO ; LIST, EDWARD O.; KOPCHICK, JOHN J.; DONATO JUNIOR, JOSE. Growth hormone receptor deletion reduces the density of axonal projections from hypothalamic arcuate nucleus neurons. Neuroscience, v. 434, p. 136-147, 2020. DOI: 10.1016/j.neuroscience.2020.03.037

    Abstract: The arcuate nucleus (ARH) is an important hypothalamic area for the homeostatic control of feeding and other metabolic functions. In the ARH, proopiomelanocortin- (POMC) and agouti-related peptide (AgRP)- expressing neurons play a key role in the central regulation of metabolism. These neurons are influenced by circulating factors, such as leptin and growth hormone (GH). The objective of the present study was to determine whether a direct action of GH on ARH neurons regulates the density of POMC and AgRP axonal projections to major postsynaptic targets. We studied POMC and AgRP axonal projections to the hypothalamic paraventricular (PVH), lateral (LHA) and dorsomedial (DMH) nuclei in leptin receptor (LepR)-deficient mice (Leprdb/db), GH-deficient mice (Ghrhrlit/lit) and in mice carrying specific ablations of GH receptor (GHR) either in LepR- or AgRP-expressing cells. Leprdb/db mice presented reduction in the density of POMC innervation to the PVH compared to wild-type and Ghrhrlit/lit mice. Additionally, both Leprdb/db and Ghrhrlit/lit mice showed reduced AgRP fiber density in the PVH, LHA and DMH. LepR GHR knockout mice showed decreased density of POMC innervation in the PVH and DMH, compared to control mice, whereas a reduction in the density of AgRP innervation was observed in all areas analyzed. Conversely, AgRP-specific ablation of GHR led to a significant reduction in AgRP projections to the PVH, LHA and DMH, without affecting POMC innervation. Our findings indicate that GH has direct trophic effects on the formation of POMC and AgRP axonal projections and provide additional evidence that GH regulates hypothalamic neurocircuits controlling energy homeostasis.

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  • IPEN-DOC 27181

    PIJEIRA, MARTHA S.O. ; NUNES, PAULO S.G.; SANTOS, SOFIA N. dos ; ZHANG, ZHENGXING; NARIO, ARIAN P. ; PERINI, EFRAIN A. ; TURATO, WALTER M.; RIERA, ZALUA R.; CHAMMAS, ROGER; ELSINGA, PHILIP H.; LIN, KUO-SHYAN; CARVALHO, IVONE; BERNARDES, EMERSON S. . Synthesis and evaluation of [18F]FEtLos and [18F]AMBF3Los as novel 18F-labelled losartan derivatives for molecular imaging of angiotensin II type 1 receptors. Molecules, v. 25, n. 8, p. 1-21, 2020. DOI: 10.3390/molecules25081872

    Abstract: Losartan is widely used in clinics to treat cardiovascular related diseases by selectively blocking the angiotensin II type 1 receptors (AT1Rs), which regulate the renin-angiotensin system (RAS). Therefore, monitoring the physiological and pathological biodistribution of AT1R using positron emission tomography (PET) might be a valuable tool to assess the functionality of RAS. Herein, we describe the synthesis and characterization of two novel losartan derivatives PET tracers, [18F]fluoroethyl-losartan ([18F]FEtLos) and [18F]ammoniomethyltrifluoroborate-losartan ([18F]AMBF3Los). [18F]FEtLos was radiolabeled by 18F-fluoroalkylation of losartan potassium using the prosthetic group 2-[18F]fluoroethyl tosylate; whereas [18F]AMBF3Los was prepared following an one-step 18F-19F isotopic exchange reaction, in an overall yield of 2.7 ± 0.9% and 11 ± 4%, respectively, with high radiochemical purity (>95%). Binding competition assays in AT1R-expressing membranes showed that AMBF3Los presented an almost equivalent binding affinity (Ki 7.9 nM) as the cold reference Losartan (Ki 1.5 nM), unlike FEtLos (Ki 2000 nM). In vitro and in vivo assays showed that [18F]AMBF3Los displayed a good binding affinity for AT1R-overexpressing CHO cells and was able to specifically bind to renal AT1R. Hence, our data demonstrate [18F]AMBF3Los as a new tool for PET imaging of AT1R with possible applications for the diagnosis of cardiovascular, inflammatory and cancer diseases.

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  • IPEN-DOC 27180

    FERREIRA, RAFAEL V. de P.; ARAUJO, LEANDRO G. de ; CANEVESI, RAFAEL L.S.; SILVA, EDSON A. da; FERREIRA, EDUARDO G.A. ; PALMIERI, MAURICIO C.; MARUMO, JULIO T. . The use of rice and coffee husks for biosorption of U (total), 241Am, and 137Cs in radioactive liquid organic waste. Environmental Science and Pollution Research, v. 27, n. 29, SI, p. 36651-36663, 2020. DOI: 10.1007/s11356-020-09727-8

    Abstract: Rice and coffee husks (raw and chemically activated) are examined as potential biosorption materials regarding their capacity to remove U (total), 241Am, and 137Cs. The physical parameters evaluated were the morphological characteristics of the biomass, real and apparent density, and surface area. Contact times for the batch experiments were 0.5, 1, 2, and 4 h, and the concentrations tested ranged between 10% of the total concentration and the radioactive waste itself without any dilution. The results were evaluated by experimental sorption capacity, ternary isotherm, and kinetics models. The kinetics results showed that equilibrium was reached after 2 h for all biomass. Raw coffee husk showed the best adsorption results in terms of maximum capacity (qmax) for all three radionuclides, which were 1.96, 39.4 × 10−6, and 46.6 × 10−9 mg g−1 for U, Am, and Cs, respectively. The biosorption process for the raw and activated rice husks was best represented by the Langmuir ternary isotherm model with two sites. For the coffee husk, in the raw and activated states, the biosorption process was best described by the modified Jain and Snoeyink ternary model. These results suggest that biosorption with these biomaterials can be applied in the treatment of liquid organic radioactive waste containing mainly uranium and americium.

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  • IPEN-DOC 27179

    CARVALHO, PATRICIA R. ; MUNITA, CASIMIRO S. ; NEVES, EDUARDO G.; ZIMPEL, CARLOS A.. A preliminary assessment of the provenance of ancient pottery through instrumental neutron activation analysis at the Monte Castelo site, Rondônia, Brazil. Journal of Radioanalytical and Nuclear Chemistry, v. 324, n. 3, p. 1053-1058, 2020. DOI: 10.1007/s10967-020-07143-3

    Abstract: This research aims to contribute to the discussion of ceramic objects found at the Monte Castelo shellmound, an archaeological site located at south-west Amazonia, Brazil. This paper provides the results of a preliminary characterization of eighty-four pottery samples using instrumental neutron activation analysis (INAA) and dating by thermoluminescence (TL). The results showed the existence of three different chemical groups whose dates range from 3000 to 1500 BP. confirming changes in clay sources during that period. These results agree with previous studies about the technological changes and continuities in the Bacabal phase, one of the oldest ceramic cultures of South America.

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  • IPEN-DOC 27178

    MILAGRE, MARIANA X. ; DONATUS, UYIME ; MOGILI, NAGA V.; SILVA, REJANE M.P. ; VIVEIROS, BARBARA V.G. de ; PEREIRA, VICTOR F.; ANTUNES, RENATO A.; MACHADO, CARULINE S.C. ; ARAUJO, JOAO V.S. ; COSTA, ISOLDA . Galvanic and asymmetry effects on the local electrochemical behavior of the 2098-T351 alloy welded by friction stir welding. Journal of Materials Science & Technology, v. 45, p. 162-175, 2020. DOI: 10.1016/j.jmst.2019.11.016

    Abstract: Scanning electrochemical microscopy (SECM) and scanning vibrating electrode technique (SVET) were used to investigate the electrochemical behaviour of the top surface of the 2098-T351 alloy welded by friction stir welding (FSW). The SVET technique was efficient in identifying the cathodic and anodic weld regions. The welding joint (WJ), which comprises the thermomechanically affected zone (TMAZ) and the stir zone (SZ), was cathodic relative to the heated affected zone (HAZ) and the base metal (BM). The reactivities of the welding joint at the advancing side (AS) and the retreating side (RS) were analyzed and compared using SECM technique in the competition mode by monitoring the dissolved oxygen as a redox mediator in 0.005 mol L−1 NaCl solution. The RS was more electrochemically active than the AS, and these results were correlated with the microstructural features of the welded alloy.

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  • IPEN-DOC 27177

    PEREIRA, LUIZ A.T. ; MARTINEZ, LUIS G. ; MUCSI, CRISTIANO S. ; REIS, LUIS A.M. dos ; ROSSI, JESUALDO L. . On the melting of zirconium alloys from scraps using electron beam and induction furnaces: recycling process viability. Journal of Materials Research and Technology, v. 9, n. 3, p. 4867-4875, 2020. DOI: 10.1016/j.jmrt.2020.03.006

    Abstract: The pressurized water reactor (PWR) employs UO2pellets as nuclear fuel, which are packedin zirconium alloy tubes called nuclear fuel cladding. In the manufacture of the nuclearfuel, machining scraps are generated which are not easily discarded as scraps because ofits high cost. These zirconium nuclear alloys are very costly and are not produced in Brazil.In this work, novel methods to recycle Zircaloy scraps using vacuum induction melting andelectron beam furnaces were used to obtain ingots. The cast ingots were subjected to ther-mal treatments and then chemically analyzed, followed by microstructural characterization,mechanical properties evaluation, and X-ray diffraction. The results indicated the feasibilityof the processes for obtaining alloys for application in the nuclear area, chemical industryor materials for biological applications such as dental prostheses.

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  • IPEN-DOC 27176

    SILVA, ANDERSON M.B.; JUNOT, DANILO O. ; CALDAS, LINDA V.E. ; SOUZA, DIVANIZIA N.. Structural, optical and dosimetric characterization of CaSO4:Tb, CaSO4:Tb, Ag and CaSO4:Tb,Ag(NP). Journal of Luminescence, v. 224, p. 1-12, 2020. DOI: 10.1016/j.jlumin.2020.117286

    Abstract: The proposal of this work was to produce and characterize CaSO4 crystals doped with terbium and silver nanoparticles for use in thermoluminescent (TL) and optically stimulated luminescent (OSL) dosimetry. The crystalline structure, morphology and optical properties of the phosphors were characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and photoluminescence. The viability of the slow evaporation route used in the production was confirmed. The silver nanoparticles (Ag(NPs)) were prepared by the method proposed by Lee and Meisel and characterized by XRD and visible absorption spectroscopy (UV–Vis). The composites were obtained from the addition of Teflon to the phosphors. Through the analyses, it was observed that the presence of silver nanoparticles slightly increases the intensity of the emission of the phosphor and shifts the dosimetric TL peak from 185 °C to 310 °C, at a heating rate of 10 °C/s. The samples presented a typical exponential OSL decay curve with a very slow component (τ3 ≥ 152 s) that indicates that the traps have a low photoionization cross-section for blue LEDs. CaSO4:Tb,Ag(NP) presented a higher sensitivity to radiation than CaSO4:Tb,Ag. The lowest detectable dose (LDD) and the fading of the TL signal of the composites were also evaluated. All samples presented a luminescent signal reproducible and linear, with TL and OSL responses proportional to the absorbed doses in the range of 169 mGy to 10 Gy.

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  • IPEN-DOC 27175

    HERNANDES, CAMILA; MIGUITA, LUCYENE; SALES, ROMARIO O. de; SILVA, ELISANGELA de P.; MENDONÇA, PEDRO O.R. de; SILVA, BRUNA L. da; KLINGBEIL, MARIA de F.G. ; MATHOR, MONICA B. ; RANGEL, ERIKA B.; MARTI, LUCIANA C.; COPPEDE, JULIANA da S.; NUNES, FABIO D.; PEREIRA, ANA M.S.; SEVERINO, PATRICIA. Anticancer activities of the quinone-methide triterpenes maytenin and 22-β-hydroxymaytenin obtained from cultivated Maytenus ilicifolia roots associated with down-regulation of miRNA-27a and miR-20a/miR-17-5p. Molecules, v. 25, n. 3, p. 1-19, 2020. DOI: 10.3390/molecules25030760

    Abstract: Natural triterpenes exhibit a wide range of biological activities. Since this group of secondary metabolites is structurally diverse, effects may vary due to distinct biochemical interactions within biological systems. In this work, we investigated the anticancer-related activities of the quinone-methide triterpene maytenin and its derivative compound 22-β-hydroxymaytenin, obtained from Maytenus ilicifolia roots cultivated in vitro. Their antiproliferative and pro-apoptotic activities were evaluated in monolayer and three-dimensional cultures of immortalized cell lines. Additionally, we investigated the toxicity of maytenin in SCID mice harboring tumors derived from a squamous cell carcinoma cell line. Both isolated molecules presented pronounced pro-apoptotic activities in four cell lines derived from head and neck squamous cell carcinomas, including a metastasis-derived cell line. The molecules also induced reactive oxygen species (ROS) and down-regulated microRNA-27a and microRNA-20a/miR-17-5p, corroborating with the literature data for triterpenoids. Intraperitoneal administration of maytenin to tumor-bearing mice did not lead to pronounced histopathological changes in kidney tissue, suggesting low nephrotoxicity. The wide-ranging activity of maytenin and 22-β-hydroxymaytenin in head and neck cancer cells indicates that these molecules should be further explored in plant biochemistry and biotechnology for therapeutic applications.

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  • IPEN-DOC 27173

    SANTOS, UANDA P.M. ; LOURENÇO, FELIPE R.; MOREIRA, EDSON G. . Experimental design and z-score results are useful tools for optimizing instrumental neutron activation analysis procedures. Journal of Radioanalytical and Nuclear Chemistry, v. 325, n. 3, p. 707-718, 2020. DOI: 10.1007/s10967-020-07150-4

    Abstract: In this study 2k experimental designs were used for the optimization of an instrumental neutron activation analysis method for the determination of bromine, chlorine, magnesium, manganese, potassium, sodium and vanadium in biological matrix materials. Depending on radionuclide half-lives, 23 or 24 experimental designs were used with irradiation time, sample–detector distance, counting time and sample decay time as factors. Gamma ray spectrometer, comparator mass fraction and sample mass were kept constant. Optimized irradiation and measurement conditions were established based on the experimental design results that used z-scores as response on a reference material for the various elements and experimental conditions.

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  • IPEN-DOC 27172

    ARAUJO, M.S. ; BARTOLOMÉ, J.F.; MELLO-CASTANHO, S. . Tribological and mechanical behaviour of 45S5 Bioglass®-based compositions containing alumina and strontium. Ceramics International, v. 46, n. 15, p. 24347-24354, 2020. DOI: 10.1016/j.ceramint.2020.06.216

    Abstract: Although bioactive glasses have been widely used for the surfaces of orthopaedic and dental implants, its limited mechanical strength, low toughness and wear resistance have prevented their use as load-bearing devices. Considering that even a small variation in the composition of such materials can deeply modify their features, inducing very different physicochemical or mechanical properties, the present research was conducted by modifying the glass network of 45S5 Bioglass® by adding Al2O3 and SrO to obtain a highly bioactive glass with improved mechanical and tribological performance for biomedical applications. The addition of 2% Al2O3 and 2% SrO produced a dense material with the same elastic modulus as 45S5 (~50 GPa). Moreover, the bending strength increased by 60% and the toughness doubled. The wear rate obtained against steel was found to be three times lower than that of 45S5. From the results, it can be assumed that both alumina and strontium synergistically play crucial roles in the mechanical and tribological properties of these new bioactive glasses.

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  • IPEN-DOC 27174

    WANG, RAYMOND Y.; FRANCO, JOSE F. da S. ; LOPEZ-VALDEZ, JAIME; MARTINS, ESMERALDA; SUTTON, VERNON R.; WHITLEY, CHESTER B.; ZHANG, LIN; CIMMS, TRICIA; MARSDEN, DEBORAH; JURECKA, AGNIESZKA; HARMATZ, PAUL. The long-term safety and efficacy of vestronidase alfa, rhGUS enzyme replacement therapy, in subjects with mucopolysaccharidosis VII. Molecular Genetics and Metabolism, v. 129, n. 3, p. 219-227, 2020. DOI: 10.1016/j.ymgme.2020.01.003

    Abstract: Vestronidase alfa (recombinant human beta-glucuronidase) is an enzyme replacement therapy (ERT) for Mucopolysaccharidosis (MPS) VII, a highly heterogeneous, ultra-rare disease. Twelve subjects, ages 8–25 years, completed a Phase 3, randomized, placebo-controlled, blind-start, single crossover study (UX003-CL301; NCT02377921), receiving 24–48 weeks of vestronidase alfa 4 mg/kg IV. All 12 subjects completed the blind-start study, which showed significantly reduced urinary glycosaminoglycans (GAG) and clinical improvement in a multi-domain responder index, and enrolled in a long-term, open-label, extension study (UX003-CL202; NCT02432144). Here, we report the final results of the extension study, up to an additional 144 weeks after completion of the blind-start study. Three subjects (25%) completed all 144 weeks of study, eight subjects (67%) ended study participation before Week 144 to switch to commercially available vestronidase alfa, and one subject discontinued due to noncompliance after receiving one infusion of vestronidase alfa in the extension study. The safety profile of vestronidase alfa in the extension study was consistent with observations in the preceding blind-start study, with most adverse events mild to moderate in severity. There were no treatment or study discontinuations due to AEs and no noteworthy changes in a standard safety chemistry panel. Out of the eleven subjects who tested positive for anti-drug antibodies at any time during the blind-start or extension study, including the baseline assessment in the blind-start study, seven subjects tested positive for neutralizing antibodies and all seven continued to demonstrate a reduction in urinary GAG levels. There was no association between antibody formation and infusion associated reactions. Subjects receiving continuous vestronidase alfa treatment showed a sustained urinary GAG reduction and clinical response evaluated using a multi-domain responder index that includes assessments in pulmonary function, motor function, range of motion, mobility, and visual acuity. Reduction in fatigue was also maintained in the overall population. As ERT is not expected to cross the blood brain barrier, limiting the impact on neurological signs of disease, and not all subjects presented with neurological symptoms, outcomes related to central nervous system pathology are not focused on in this report. Results from this study show the long-term safety and durability of clinical efficacy in subjects with MPS VII with long-term vestronidase alfa treatment.

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  • IPEN-DOC 27171

    FONTES, E.H. ; NANDENHA, J. ; SOUZA, R.F.B. de ; ANTONIO, F.C.T.; HOMEM-DE-MELLO, P.; NETO, A.O. . Au core stabilizes CO adsorption onto Pd leading to CO2 production. Materials Today Advances, v. 6, p. 1-9, 2020. DOI: 10.1016/j.mtadv.2020.100070

    Abstract: Au core and Pd shell supported on carbon structure Au@Pd/C can cleave the CeC bond of ethanol molecules leading to the production of a relatively high amount of CO2 when compared with Pd/C electrocatalyst as the attenuated total reflectance - Fourier transform infrared (ATR-FTIR) experiment shows. Density functional theory (DFT) calculations showed that this could be explained by the oxidation of CO species adsorbed into Pd sites that has a modified electronic structure compared with Pd/C. In terms of DFT analysis, the highest thermodynamical stability of CO in Pd shell with Au core atoms, when compared with Pd/C is because of the increase of virtual orbital states near Fermi level that can be occupied by valence electrons of CO molecule. The d-band center shift is experimentally verified using the valence band X-ray photoelectron spectroscopy and theoretically predicted by the Generalized Koopmans’ Theorem. Besides that, Au@Pd/C electrocatalyst has a better electrochemical activity when compared with Pd/C.

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  • IPEN-DOC 27170

    CHIARI, MARINA D.S.; RODRIGUES, MARCELA C.; PINTO, MIRELLA F.C.; VIEIRA, DOUGLAS N.; VICHI, FLAVIO M.; VEGA, OSCAR ; CHRZANOWSKI, WOJCIECH; NAGAOKA, NORIYUKI; BRAGA, ROBERTO R.. Development of brushite particles synthesized in the presence of acidic monomers for dental applications. Materials Science & Engineering C, v. 116, p. 1-8, 2020. DOI: 10.1016/j.msec.2020.111178

    Abstract: Objectives: To synthesize and characterize brushite particles in the presence of acidic monomers (acrylic acid/ AA, citric acid/CA, and methacryloyloxyethyl phosphate/MOEP) and evaluate the effect of these particles on degree of conversion (DC), flexural strength/modulus (FS/FM) and ion release of experimental composites. Methods: Particles were synthesized by co-precipitation with monomers added to the phosphate precursor solution and characterized for monomer content, size and morphology. Composites containing 20 vol% brushite and 40 vol% reinforcing glass were tested for DC, FS and FM (after 24 h and 60 d in water), and 60-day ion release. Data were subjected to ANOVA/Tukey tests (DC) or Kruskal–Wallis/Dunn tests (FS and FM, alpha: 5%). Results: The presence of acidic monomers affected particle morphology. Monomer content on the particles was low (0.1–1.4% by mass). Composites presented similar DC. For FS/24 h, only the composite containing DCPD_AA was statistically similar to the composite containing 60 vol% of reinforcing glass (without brushite, “control”). After 60 days, all brushite-containing materials showed similar FS, statistically lower than the control composite (p<0.01). Composites containing DCPD_AA, DCPD_MOEP or DCPD_U (“unmodified”) showed statistically similar FM/24 h, higher than the control composite. After prolonged immersion, all composites were similar to the control composite, except DCPD_AA. Cumulative ion release ranged from 21 ppm to 28 ppm (calcium) and 9 ppm to 17 ppm (phosphate). Statistically significant reductions in ion release between 15 and 60 days were detected only for the composite containing DCPD_MOEP. Significance: Acidic monomers added to the synthesis affected brushite particle morphology. After 60-day storage in water, composite strength was similar among all brushite-containing composites. Ion release was sustained for 60 days and it was not affected by particle morphology.

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  • IPEN-DOC 27169

    SILVA, MATHEUS F.B. da; PACHECO, CAROLINE V.; PERES, RENATO M.; MIRANDA, LEILA F. de; LIMA, NELSON B. de ; OLIVEIRA, RENE R. de ; BERNUSSI, AYRTON; MUNHOZ JUNIOR, ANTONIO H.. Synthesis of pseudoboehmite: effect of acetate ion. Materials Research, v. 23, n. 1, p. 1-9, 2020. DOI: 10.1590/1980-5373-MR-2019-0583

    Abstract: Pseudoboehmite (AlOOH.xH2O) is one of the precursors of alumina. Its calcination produces different phases of alumina and at 1200º C the most stable phase, α-alumina, is formed. The synthesis of pseudoboehmite by the sol-gel process results in a product with high purity, high specific surface area, and high reproducibility. The aging of the pseudoboehmite at temperatures above room temperature results in pseudoboehmites with distinct properties. In this work we report the synthesis of pseudoboehmite by the sol-gel process, using aluminum nitrate and aluminum chloride as precursors, and investigate the effect of acetate ion on crystallinity, adsorption capacity, particle morphology, thermal properties and specific surface area. The X-ray diffraction data of the synthesized pseudoboehmites in the presence of the acetate ion revealed high quality nanoparticles.

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  • IPEN-DOC 27168

    COLOMBO, TIAGO C.A.; REGO, RONNIE; FARIA, ALFREDO R. de; OTUBO, JORGE . Processing-induced residual stresses in TWIP steel weld spots. Materials and Manufacturing Processes, v. 35, n. 5, p. 572-578, 2020. DOI: 10426914.2020.1734619

    Abstract: The present study investigates the evolution of the residual stresses in TWIP steels induced by manufacturing chain for the production of automotive body-in-white. Two different manufacturing routes were considered. The first route encompassed a plastic deformation prior to the welding stage, whereas the second involved the spot welding followed by a baking treatment. A convergent approach was adopted to isolate the effects of the first and final manufacturing steps. The findings showed that the plastic deformation prior to the welding stage is not annihilated by the welding thermomechanical cycle. Abrupt hardness gradients along small material fractions are observed. The residual stresses state changes, although its profile is still defined by the welding stage. The post-weld bake treatment showed to promote slight residual stresses relaxation, but it is not effective in inducing the same post-weld residual stresses state for different RSW parameters set.

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  • IPEN-DOC 27167

    CARVALHO, S.G.M. ; MUCCILLO, E.N.S. ; MARQUES, F.M.B.; MUCCILLO, R. . Electric field-assisted sintering (gadolinia-doped ceria/alkali salts) composite membranes. Materialia, v. 11, 2020. DOI: 10.1016/j.mtla.2020.100679

    Abstract: Composite ceramic membranes were prepared according to two routes: (i) vacuum impregnation of molten eutec- tic sodium-lithium carbonates (NLC) into porous ceria-20 mol% gadolinia (20GDC) solid electrolytes; (ii) electric field-assisted sintering of a 25 wt% NLC/75 wt% 20GDC mixture. Porous 20GDC ceramics were obtained by controlled thermal removal of 40 vol% KCl added as pore former. Electric field-assisted (flash) sintering was car- ried out monitoring thickness during application of 200 V cm − 1 to the specimen positioned in a sample chamber inserted in a vertical dilatometer. The surfaces of the sintered membranes were observed in a scanning electron microscope. Electrochemical impedance spectroscopy measurements were performed in the 5 Hz to 13 MHz fre- quency range in the 280–580°C range. Arrhenius plots showed the transition from oxide ion conduction (due to the solid electrolyte) to carbonate ion conduction (due to the molten NLC). Membranes flash sintered at 420°C in 2 min showed electrical conductivity similar to membranes conventionally sintered at 690°C for 2 h.

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  • IPEN-DOC 27166

    COSTA, ISRAEL F.; PIRES, GILVAN P.; ESPÍNOLA, JOSÉ G.P.; BRITO, HERMI F.; FELINTO, MARIA C.F.C. ; FAUSTINO, WAGNER M.; TEOTONIO, ERCULES E.S.. Luminescence properties of the Ln–EDTA complexes covalently linked to the chitosan biopolymers containing β-diketonate as antenna ligands. Luminescence, v. 35, n. 3, p. 365-372, 2020. DOI: 10.1002/bio.3735

    Abstract: This paper reports on the preparation, characterization, and photoluminescence properties of novel hybrid materials, in which the EDTA–Ln–L complexes (where L: H2O, acac, bzac, dbm, and tta ligands, and Ln: Eu, Gd, and Tb) were covalently linked to the precursor medium molecular weight chitosan surface (CS) matrices or on the chitosan surfaces previously crosslinked with epichlorohydrin (CSech). The emission spectra of these materials were characterized by intraconfigurational-4fN transitions centred on the Eu3+ and Tb3+ ions. Some broad bands from the polymeric matrix were also observed in the emission spectra, however the relative intensities of the intraconfigurational bands increased significantly for systems containing diketonate ligands when the antenna effect became more efficient. The values of the radiative rates (Arad) were higher for crosslinked hybrid systems with epichlorohydrin, while nonradiative rates (Anrad) presented the opposite behaviour. These data contributed to an increase in the values of emission quantum efficiency (η) for crosslinked materials. The effect of the modification process and antenna ligand on the values of intensities, intensity parameters Ω2 e Ω4 of the Eu3+ complexes were also investigated. The results showed that the crosslinked biopolymer surfaces have great potential for applications in molecular devices light converters.

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  • IPEN-DOC 27165

    FREIRE, BRUNA M.; LANGE, CAMILA N.; PEDRON, TATIANA; MONTEIRO, LUCILENA R. ; SANCHES, LIVIA R.; PEDREIRA-FILHO, WALTER dos R.; BATISTA, BRUNO L.. Occupational exposure of foundry workers assessed by the urinary concentrations of 18 elements and arsenic species. Journal of Trace Elements in Medicine and Biology, v. 62, p. 1-11, 2020. DOI: 10.1016/j.jtemb.2020.126593

    Abstract: Background: Some raw materials applied in Fe foundry industries may contain potentially toxic elements. Thus, foundry worker’s occupational exposure is a constant health concern. Method: In this study, 194 urine samples from foundry workers were analyzed by inductively coupled plasma mass spectrometry for biomonitoring of Al, As, Ba, Cd, Co, Cr, Cs, Cu, Fe, I, Mn, Ni, Pb, Sb, Sn, Se, U and Zn. Moreover, arsenic speciation was performed in representative samples of production sector workers (group A) and administration sector workers (group B). Results: Concentrations of As, Pb, Cd, Cu, Cs, I, Sb in urines from group A were higher than those found for group B. Samples of group A presented Cs, Ni, Mn, Pb, U and Zn concentrations higher than values reported for exposed workers assessed by other studies. Forty-four samples from group A exceed As-reference limits. Group A had approximately seven times more inorganic As (as arsenite) and 14 times more organic As (as dimethyl As) than group B. A statistically significant difference was observed in the elemental concentration in the workers' urine by the time in the function. Moreover, alcohol consumption is probably influencing the urine concentration of As, Ba, Cd, Co, Cu, Fe, I, Se and Zn. Conclusion: The monitored foundry workers are exposed to potentially toxic elements and more attention must be given to their health. Therefore, workplace safety conditions must be improved, and constant biomonitoring is necessary to ensure workers' health.

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  • IPEN-DOC 27164

    BENALCAZAR JALKH, E.B.; BERGAMO, E.T.P.; MONTEIRO, K.N.; CESAR, P.F.; GENOVA, L.A. ; LOPES, A.C.O.; LISBOA FILHO, P.N.; COELHO, P.G.; SANTOS, C.F.; BORTOLIN, F.; PIZA, M.M.T.; BONFANTE, E.A.. Aging resistance of an experimental zirconia-toughened alumina composite for large span dental prostheses: optical and mechanical characterization. Journal of the Mechanical Behavior of Biomedical Materials, v. 104, p. 1-9, 2020. DOI: 10.1016/j.jmbbm.2020.103659

    Abstract: Purpose: To synthesize a zirconia-toughened alumina (ZTA) composite with 85% alumina matrix reinforced by 15% zirconia and to characterize its optical and mechanical properties before and after artificial aging, to be compared with a conventional dental zirconia (3Y-TZP). Material and methods: After syntheses, ZTA and 3Y-TZP powders were uniaxially and isostatically pressed. Greenbody samples were sintered and polished to obtain 80 disc-shaped specimens per group (12 x 1 mm, ISO 6872:2015). The crystalline content and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Optical properties were determined by the calculation of contrast ratio (CR) and translucency parameter (TP) using reflectance data. Mechanical properties were assessed by Vickers hardness, fracture toughness and biaxial flexural strength test (BFS). All analyses were conducted before and after artificial aging (20h, 134 °C, 0.22 MPa). Optical parameters and microhardness differences were evaluated through repeated-measures analysis of variance (p < 0.05). BFS data were analyzed using Weibull statistics (95% CI). Results: The synthesis of the experimental ZTA composite was successful, with 98% of theoretical density, as shown in the SEM images. XRD patterns revealed typical zirconia and alumina crystalline phases. ZTA optical properties parameters showed no effect of aging, with a high CR and low TP values denoting a high maskingability. 3Y-TZP presented lower masking-ability and aging significantly affected its optical properties. ZTA Vickers hardness, fracture toughness and Weibull parameters, including characteristic stress and Weibull modulus were not influenced by aging, while 3Y-TZP presented a significant decrease in characteristic stress and increase in fracture toughness after aging. The ZTA probability of survival for missions of 300 and 500 MPa was estimated at ~99% validating its use for 3-unit posterior fixed dental prostheses (FDP), and no different from conventional 3Y-TZP. At high-stress mission (800 MPa) a significant decrease in probability of survival was observed for aged 3Y-TZP (84%) and for immediate and aged ZTA (73 and 82% respectively). Conclusion: The ZTA composite presented a dense microstructure, with preservation of the crystalline content, optical and mechanical properties after artificial aging, which encourages future research to validate its potential use for large span FDP.

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  • IPEN-DOC 27163

    DIAZ, J.C.C.A. ; MUCCILLO, R. . Liquid-phase flash sintering 8YSZ with alkali halide sintering aids. Journal of the European Ceramic Society, v. 40, n. 12, p. 4299-4303, 2020. DOI: 10.1016/j.jeurceramsoc.2020.03.022

    Abstract: The properties of ZrO2: 8 mol% Y2O3 (8YSZ) ceramics with LiF and KCl sintering aids for liquid phase formation during electric field-assisted sintering were studied. Sintering experiments were carried out at 650 °C under 200 V cm−1 AC electric field by varying current density, current application time, as well as LiF and KCl contents. Pellets sintered with KCl addition had cavities, cracks and fractures. Pellets sintered with 15 wt.% LiF, on the other hand, were homogeneous after thermal removal of LiF upon Joule heating. Low electric current densities coupled with longer application times produced homogeneous specimens. Three different stages were identified during sintering experiments: (i) LiF melting with the electric field applied at furnace temperatures lower than its melting point, (ii) shrinkage due to liquid phase formation and LiF removal, (iii) final densification due to grain growth and pore elimination. The electrical behavior and an estimate of the porosity were carried out by electrochemical impedance spectroscopy measurements.

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  • IPEN-DOC 27162

    MARCELLO, BIANCA A. ; CORREA, OLANDIR V. ; BENTO, RODRIGO T. ; PILLIS, MARINA F. . Effect of growth parameters on the photocatalytic performance of TiO2 films prepared by MOCVD. Journal of the Brazilian Chemical Society, v. 31, n. 6, p. 1270-1283, 2020. DOI: 10.21577/0103-5053.20200012

    Abstract: The present study evaluated the main factors that influence the photocatalytic activity of titanium dioxide (TiO2) films grown by metalorganic chemical vapor deposition (MOCVD) at 400 and 500 °C, in different growth times. The photocatalytic behavior was analyzed by measuring the methyl orange dye degradation at different pH values. Structural and morphological characteristics, and the recyclability of the catalysts for several cycles were also investigated. Anatase phase was identified in all films. The higher photodegradation performances were obtained at acidic pH. The results demonstrated that the photocatalyst thickness is an important parameter in heterogenous photocatalysis. The best photocatalytic result occurred for the 395 nm-thick TiO2 film grown at 400 °C, which presented 65.3% of the dye degradation under UV light. The recyclability experiments demonstrated that the TiO2 films grown by MOCVD present a great stability after several photocatalytic cycles, which allows their practical application for water treatment with high efficiency.

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  • IPEN-DOC 27161

    TUDELA, DIEGO R.G. ; ARAUJO, ASTOLFO G.M.; TATUMI, SONIA H.; MITTANI, JUAN C.R.; MUNITA, CASIMIRO S. . Preliminary evidence of prehistoric human activity by chemical analysis of sediments from Lapa Grande de Taquaraçu archaeological site using INAA. Journal of Radioanalytical and Nuclear Chemistry, v. 325, n. 3, p. 725-736, 2020. DOI: 10.1007/s10967-020-07217-2

    Abstract: This paper analyzes the mass fractions of Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Nd, Rb, Sc, Sm, Ta, Tb, Th, U, Yb and Zn determined from sixty sediment samples obtained from the Lapa Grande de Taquaraçu archaeological site using instrumental neutron activation analysis, INAA. The archaeological site is located in the municipality of Jaboticatubas, about 60 km from Belo Horizonte, Minas Gerais State, Brazil. The dataset was explored by means of cluster analysis, principal component analysis and discriminant analysis. The study showed three different compositional groups related to anthropogenic sediment, fluvial system and oxisols, respectively. The crystalline structure of each group were studied using X-ray diffraction, XRD.

    Palavras-Chave: archaeological sites; chemical composition; isotope dating; neutron activation analysis; sediments; thorium; trace amounts; uranium

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  • IPEN-DOC 27160

    ARAUJO, MARIANA S. ; SILVA, ANTONIO C. ; BARTOLOMÉ, JOSÉ F.; MELLO-CASTANHO, SONIA . Structural and thermal behavior of 45S5 Bioglass®-based compositions containing alumina and strontium. Journal of the American Ceramic Society, v. 103, n. 6, p. 3620-3630, 2020. DOI: 10.1111/jace.17061

    Abstract: The present research exposes the influence of 2 mol% of Al2O3 and 2 mol% SrO in 45S5 Bioglass®-based compositions. Four compositions were produced to elucidate the difference in how both oxides influence structure and thermal behavior separately and their synergy when together. Thermal properties, crystallization tendency, and sintering behavior was evaluated by differential scanning calorimetry, hot stage microscopy, and dilatometry. Changes of medium-range structures were characterized by Qn distribution of Raman spectroscopy and evaluation of 31P, 27Al, 23Na, and 29Si environment obtained by magic angle spinning nuclear magnetic resonance. Despite Qn distribution was predominantly Q2 in all samples, the composition criteria used enabled improved processing and stabilibity characteristics. The addition of Al2O3 and SrO promoted larger sinterability parameter (Sc) which indicates better sintering behavior, the glass stability against crystallization doubled (KH) compared to 45S5 and the processing window enlarged from 106 to 171.

    Palavras-Chave: glass; raman spectroscopy; aluminium oxides; strontium oxides; thermodynamic properties; crystallization; sintering; oxides

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  • IPEN-DOC 27159

    LOPES, RENATO P.; PEREIRA, JAMIL C.; DILLENBURG, SERGIO R.; TATUMI, SONIA H.; YEE, MARCIO; FIGUEIREDO, ANA M.G. ; KINOSHITA, ANGELA; BAFFA, OSWALDO. Late Pleistocene-Holocene fossils from Mirim Lake, Southern Brazil, and their paleoenvironmental significance: I - Vertebrates. Journal of South American Earth Sciences, v. 100, p. 1-19, 2020. DOI: 10.1016/j.jsames.2020.102566

    Abstract: Mirim Lake is located in the southern Brazilian/northeastern Urugayan coastal plain. Fossils of mollusks have been discovered on its shores since the XIX century, and in recent years, several new remains of invertebrates and vertebrates have been found in the Brazilian area of the lake that provide insights on the geological evolution and environmental changes that affected this lake during the late Quaternary. In this first of two papers describing these new findings we focus on vertebrates, consisting of aquatic and terrestrial taxa. The former include the first associated fossil remains of one adult and one juvenile balaenid whale known in Brazil, probably a female and calf of the southern right whale (baleia-franca) Eubalaena australis, besides bull sharks (Carcharhinus leucas) also recorded for the first time in southern Brazil, rays (Dasyatidae and Myliobatidae) and teleost fishes. The fossils of terrestrial vertebrates include several extinct mammals, found on the margins and retrieved from the lake bottom by fishermen at depths of up to 4 m. One molar tooth of Toxodon discovered in situ in one irrigation channel yielded an electron spin resonance (ESR) age of 68 ± 13 ka, in agreement with an age of 32.8 ± 5.1 ka obtained in quartz grains extracted from a caliche nodule collected above that fossil and dated by optically-stimulated luminescence (OSL). Other quartz grains in the same nodule that yielded ages of 16.9 ± 2.5 ka indicate partial dissolution of the caliche by increased rainfall at the beginning of the last glacialinterglacial transition (Termination I) . The lake was invaded by marine waters and organisms during the Holocene sea-level highstand of +3 m around 5–6 ka b2k through paleo-connections with the Atlantic Ocean, becoming a paleo-lagoon. At that time coastal waters were warmer than today, as indicated by the presence of the tropical shark C. leucas. The ESR and OSL ages indicate chronocorrelation with the Pleistocene fossil-bearing Santa Vitória Formation that outcrops to the east. The fossil and sedimentary records indicate that the geological evolution and environmental conditions of the lake were controlled by climate and sea-level oscillations related to glacial-interglacial cycles.

    Palavras-Chave: pleistocene epoch; quaternary period; vertebrates; paleontology; sediments; coastal regions; lakes; south america; fossils; environment

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  • IPEN-DOC 27158

    FARIA, FABIO H.C.; KINOSHITA, ANGELA; CARVALHO, ISMAR de S.; ARAUJO-JUNIOR, HERMINIO I. de; PEGORIN, PRISCILA; FIGUEIREDO, ANA M.G. ; BAFFA, OSWALDO. ESR dating of late Quaternary megafauna fossils from João Dourado, Bahia, Brazil. Journal of South American Earth Sciences, v. 101, p. 1-7, 2020. DOI: 10.1016/j.jsames.2020.102586

    Abstract: We applied the ESR (Electron Spin Resonance) dating method to fossils of Notiomastodon platensis (two teeth) and Toxodontinae (two teeth) found in the fossiliferous deposit of Lajedão do Patrício, João Dourado, State of Bahia, Brazil, to identify the period of formation of this fossil accumulation. Neutron Activation Analysis was applied to determine the concentrations of the main radioisotopes in enamel, dentine and sediment. The ages found for N. platensis are 16.8 ± 2.6 ka and 12.5 ± 2.3 ka, while the ages for Toxodontinae are 9.6 ± 1 ka and 9.1 ± 1 ka. The results for Notiomastodon. platensis and Toxodontinae are similar to other fossiliferous of Brazil. The estimated maximum time-averaging for Lajedão do Patrício is 11.3 ka, indicating a long period of accumulation of skeletal remains, attributed to resedimentation and reworking. The crossing between the period of formation of fossil assemblage Lajedão do Patrício and ages of climatic variations diponible in paleoclimatic curves produced for the Quaternary of northeastern Brazil indicates different climatic and environmental conditions during the formation of the deposit.

    Palavras-Chave: fossils; electron spin resonance; quaternary period; teeth; dentin; enamels; tanks; time dependence; vertebrates; sediments

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A pesquisa no RD utiliza os recursos de busca da maioria das bases de dados. No entanto algumas dicas podem auxiliar para obter um resultado mais pertinente.

É possível efetuar a busca de um autor ou um termo em todo o RD, por meio do Buscar no Repositório , isto é, o termo solicitado será localizado em qualquer campo do RD. No entanto esse tipo de pesquisa não é recomendada a não ser que se deseje um resultado amplo e generalizado.

A pesquisa apresentará melhor resultado selecionando um dos filtros disponíveis em Navegar

Os filtros disponíveis em Navegar tais como: Coleções, Ano de publicação, Títulos, Assuntos, Autores, Revista, Tipo de publicação são autoexplicativos. O filtro, Autores IPEN apresenta uma relação com os autores vinculados ao IPEN; o ID Autor IPEN diz respeito ao número único de identificação de cada autor constante no RD e sob o qual estão agrupados todos os seus trabalhos independente das variáveis do seu nome; Tipo de acesso diz respeito à acessibilidade do documento, isto é , sujeito as leis de direitos autorais, ID RT apresenta a relação dos relatórios técnicos, restritos para consulta das comunidades indicadas.

A opção Busca avançada utiliza os conectores da lógica boleana, é o melhor recurso para combinar chaves de busca e obter documentos relevantes à sua pesquisa, utilize os filtros apresentados na caixa de seleção para refinar o resultado de busca. Pode-se adicionar vários filtros a uma mesma busca.

Exemplo:

Buscar os artigos apresentados em um evento internacional de 2015, sobre loss of coolant, do autor Maprelian.

Autor: Maprelian

Título: loss of coolant

Tipo de publicação: Texto completo de evento

Ano de publicação: 2015

Para indexação dos documentos é utilizado o Thesaurus do INIS, especializado na área nuclear e utilizado em todos os países membros da International Atomic Energy Agency – IAEA , por esse motivo, utilize os termos de busca de assunto em inglês; isto não exclui a busca livre por palavras, apenas o resultado pode não ser tão relevante ou pertinente.

95% do RD apresenta o texto completo do documento com livre acesso, para aqueles que apresentam o significa que e o documento está sujeito as leis de direitos autorais, solicita-se nesses casos contatar a Biblioteca do IPEN, bibl@ipen.br .

Ao efetuar a busca por um autor o RD apresentará uma relação de todos os trabalhos depositados no RD. No lado direito da tela são apresentados os coautores com o número de trabalhos produzidos em conjunto bem como os assuntos abordados e os respectivos anos de publicação agrupados.

O RD disponibiliza um quadro estatístico de produtividade, onde é possível visualizar o número dos trabalhos agrupados por tipo de coleção, a medida que estão sendo depositados no RD.

Na página inicial nas referências são sinalizados todos os autores IPEN, ao clicar nesse símbolo será aberta uma nova página correspondente à aquele autor – trata-se da página do pesquisador.

Na página do pesquisador, é possível verificar, as variações do nome, a relação de todos os trabalhos com texto completo bem como um quadro resumo numérico; há links para o Currículo Lattes e o Google Acadêmico ( quando esse for informado).

ATENÇÃO!

ESTE TEXTO "AJUDA" ESTÁ SUJEITO A ATUALIZAÇÕES CONSTANTES, A MEDIDA QUE NOVAS FUNCIONALIDADES E RECURSOS DE BUSCA FOREM SENDO DESENVOLVIDOS PELAS EQUIPES DA BIBLIOTECA E DA INFORMÁTICA.

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.

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.

1. Portaria IPEN-CNEN/SP nº 387, que estabeleceu os princípios que nortearam a criação do RDI, clique aqui.


2. A experiência do Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP) na criação de um Repositório Digital Institucional – RDI, clique aqui.