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  • IPEN-DOC 26393

    FERREIRA, EDUARDO G.A. ; MARUMO, JULIO T. ; FRANCO, MARGARETH K.K.D. ; YOKAICHIYA, FABIANO; VICENTE, ROBERTO . 10000 years cement: Can hydrated cement last as much as long-lived radionuclides?. Cement and Concrete Composites, v. 103, p. 339-352, 2019. DOI: 10.1016/j.cemconcomp.2019.05.016

    Abstract: This review is focused on the long-term performance of cementitious materials in a repository for radioactive waste. During the last few years, the disposal of disused sealed radioactive sources (DSRS) in a borehole type repository has been studied by many countries. The borehole concept is particularly useful to dispose of spent nuclear fuel and DSRS. In boreholes for DSRS, cementitious materials are intended to be used as structural material, immobilization matrix and as backfill. The understanding of the performance of these materials is essential to ensure the safety of the facilities during their required lifetime, from centuries to many thousands of years, depending on the initial activity and half-life of the waste. This review approaches the behavior of the cement from the hydration and hardening to the long-term processes that can affect its durability. Three main causes of failure of repository-engineered barriers are recognized: a) the formation of a preferential pathway for the migration of the contained radionuclides to the biosphere; b) loss of resistance and cohesion of the structural cementitious material; and c) the increase in the corrosion processes of the metallic components of the structures that affect the overall containment of the facility.

    Palavras-Chave: cements; cement industry; portland cement; radioactive wastes; geologic formations; underground disposal; performance; chemical composition; mineralogy; radiations; magnetic fields; hydration

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  • IPEN-DOC 25206

    FREITAS, LUCAS F. de ; VARCA, GUSTAVO H.C. ; BATISTA, JORGE G. dos S. ; LUGAO, ADEMAR B. . An overview of the synthesis of gold nanoparticles using radiation technologies. Nanomaterials, v. 8, n. 11, 2018. DOI: 10.3390/nano8110939

    Abstract: At a nano-level, optical properties of gold are unique and gave birth to an emerging platform of nanogold-based systems for diverse applications, because gold nanoparticle properties are tunable as a function of size and shape. Within the available techniques for the synthesis of gold nanoparticles, the radiolytic synthesis allows proper control of the nucleation process without the need for reducing agents, in a single step, combined or not with simultaneous sterilization. This review details and summarizes the use of radiation technologies for the synthesis and preparation of gold nanoparticles concerning fundamental aspects, mechanism, current pathways for synthesis and radiation sources, as well as briefly outlines final applications and some toxicity aspects related to nanogold-based systems.

    Palavras-Chave: gold; nanoparticles; gamma radiation; electron beams; x-ray sources; radiolysis; nanotechnology; medicine; diagnostic uses; ionizing radiations

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  • IPEN-DOC 27582

    LIMA, CAROLINE S.A. de ; BALOGH, TATIANA S. ; VARCA, JUSTINE P.R.O. ; VARCA, GUSTAVO H.C. ; LUGAO, ADEMAR B. ; CAMACHO-CRUZ, LUIS A.; BUCIO, EMILIO; KADLUBOWSKI, SLAWOMIR S.. An updated review of macro, micro, and nanostructured hydrogels for biomedical and pharmaceutical applications. Pharmaceutics, v. 12, n. 10, p. 1-28, 2020. DOI: 10.3390/pharmaceutics12100970

    Abstract: Hydrogels are materials with wide applications in several fields, including the biomedical and pharmaceutical industries. Their properties such as the capacity of absorbing great amounts of aqueous solutions without losing shape and mechanical properties, as well as loading drugs of different nature, including hydrophobic ones and biomolecules, give an idea of their versatility and promising demand. As they have been explored in a great number of studies for years, many routes of synthesis have been developed, especially for chemical/permanent hydrogels. In the same way, stimuli-responsive hydrogels, also known as intelligent materials, have been explored too, enhancing the regulation of properties such as targeting and drug release. By controlling the particle size, hydrogel on the micro- and nanoscale have been studied likewise and have increased, even more, the possibilities for applications of the so-called XXI century materials. In this paper, we aimed to produce an overview of the recent studies concerning methods of synthesis, biomedical, and pharmaceutical applications of macro-, micro, and nanogels.

    Palavras-Chave: hydrogels; drugs; synthesis; cross-linking; skin; animal tissues; gamma radiation

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  • IPEN-DOC 27621

    COSTA, ROBSON S. ; MOURA, ESPERIDIANA A.B. . A bibliometric analysis of the strategy and performance measurement of the polymer matrix nanomaterials development scenario globally, and the participation of Brazil. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 329-342, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_31

    Abstract: Extensive studies have been conducted worldwide on the strategy for the development of nanomaterials. One of the known strategies for this has aroused interest in the market is the incorporation of the nanoparticles, extracted from the residues in thematrices of the polymers for the production of environmentally correct nanocomposites. This work presents a survey of the scientific knowledge of nanomaterials of the polymer matrix and a panoramic view of the evolution of these nanomaterials are subject, in order to meet the criteria of sustainable development due to the environmental concerns. This study also intends to use bibliometric tools to database acquisition and analysis of bibliographic reviews for an evaluation of the scenarios in the world on the development of polymeric nanomaterials based on three different classes of polymeric nanocomposites: polymer/clay; polymer/graphene, and polymer/nanocellulose nanocomposites.

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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.

    Palavras-Chave: gold; nanoparticles; synthesis; chemistry; ecology; polyphenols; fishes

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  • IPEN-DOC 27622

    SOARES, CARLOS ; SANTANA, JULYANA ; GUVEN, OLGUN; MOURA, ESPERIDIANA A.B. . A comparison between graphene oxide and reduced graphene oxide as reinforcement agents in polypropylene nanocomposite using irradiated polypropylene as compatibilizer. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 385-394, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_36

    Abstract: Graphene is thematerial with the bestmechanical resistance ever encountered. Various types of studies have been carried out on possible applications. The use as a reinforcement in nanocomposites has shown to be a promising field, but some studies indicate that the graphene oxide (GO) and reduced graphene oxide (RGO) have better results as reinforcement, due to the functional groups,which allowa better adhesion with the matrix. This study analyzes the production of polypropylene (PP) nanocomposite comparing the use of graphene oxide (GO) and reduced graphene oxide (RGO) as fillers and irradiated polypropylene as a coupling agent.Atwin-screw extruder and injection molding machine were used to produce the nanocomposite PP reinforced with 0.2 wt% of GO and RGO by melt blending. The GO and RGO were characterized byXRDanalysis.The nanocomposite sampleswere characterized by XRD, SEM, TG, DSC and mechanical test.

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  • IPEN-DOC 26288

    ZDOROVETS, MAXIM; MASHENTSEVA, ANASTASSIYA; ANGNES, LUCIO; JACOVONE, RAYNARA M.S. ; SAKATA, SOLANGE K. . Electrochemical behaviour of track-etched membranes with embedded copper nanotubes. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 2532-2537.

    Abstract: Track-etched membranes (TeMs) are thin polymer films with pores of various geometries made by irradiating on the DC-60 cyclotron and subsequent chemical etching. The objective of this work is to evaluate the electrochemical behavior of track-etched membranes with embedded copper nanotubes (TeMs/CuNT) using Cyclic Voltammetry. TeMs were prepared from 12.0 μm polyethylene terephthalate (PET) film by irradiation with 84Kr+15 on the DC-60 heavy ion accelerator. The irradiated film was etched in a basic solution followed by H2O2/UV system. The characterization was performed by scanning electron microscopy (SEM). For the electroless plating consists of three successive stages: sensitization, activation and directly deposition. The electrochemical studies was performed in two different media KOH and Na2SO4 adding adding 100uL aliquots of nitrate solution using Pt as counter electrode, Ag/AgI as reference and the copper as work electrode. The results showed the potential of TeMs/CuNT as nitrate sensor in sodium sulfate medium.

    Palavras-Chave: copper; electrochemistry; electrolytes; etching; films; gamma radiation; heavy ion accelerators; irradiation; nanotubes; nitrates; scanning electron microscopy; sodium sulfates; water

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  • IPEN-DOC 27626

    SANTOS, BIANCA S. ; INACIO, ANDRE L.N. ; BARTOLOMEI, SUELLEN S. ; SILVA, TAISE B.S. ; CARMO, KARINA L.S. ; OLIVEIRA, RENE R. ; MOURA, ESPERIDIANA A.B. . Influence of the reduced graphene oxide incorporation on properties of acrylonitrile butadiene styrene (ABS). In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 599-607, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_59

    Abstract: The purpose of this study was to evaluate the influence of incorporation of the reduced graphene oxide on properties of acrylonitrile butadiene styrene (ABS). The incorporation of 0.5 and 1.5 wt% of RGO into ABS matrix was carried out by melting extrusion process using a twin-screw extruder and injection molding machine. The properties of ABS/RGO nanocomposite samples were investigated by tensile and impact Izod tests, FE-SEM, and XRD analysis. The results showed that the incorporation of small amount of RGO into ABS matrix led to obtaining of polymeric nanocomposite with superior mechanical properties when compared with original properties of ABS matrix.

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  • IPEN-DOC 27628

    BARTOLOMEI, MARCIO R.X. ; CARMO, KARINA H.S. ; SANTOS, BIANCA S. ; BARTOLOMEI, SUELLEN S. ; OLIVEIRA, RENE R. ; MOURA, ESPERIDIANA A.B. . Investigation on mechanical and thermal behaviours of PBAT/PLA blend reinforced with reduced graphene oxide nanosheets. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 631-639, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_62

    Abstract: The aim of this study was to process and investigate the changes in the mechanical and morphological properties of the biodegradable nanocomposites based on polybutylene adipate-co-terephthalate (PBAT)/poly(lactic acid) (PLA) blend (PBAT/PLA blend) due to the incorporation of reduced graphene oxide (RGO) nanosheets. The biodegradable polymeric nanocomposites were prepared by melting extrusion process using a twin-screw extruder machine. The influence of the RGO nanosheets incorporation on mechanical and thermal properties of PBAT/PLA blend was investigated by tensile Thermogravimetric (TG), X-Ray diffraction (XRD), differential scanning calorimetry (DSC), and tensile test analysis. Results showed that incorporation of the small amount ofRGO(0.1wt.%) ofRGOnanosheets in the blend matrix of PBAT/PLA resulted in an important gain of mechanical properties of the blend. This result indicates that a very small amount of RGO nanosheets addition in the PBAT/PLA can lead to obtaining materials with superior properties suitable for several industrial applications.

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  • IPEN-DOC 26156

    TAPPIZ, BRUNO ; MOREIRA, EDSON G. . Measurement uncertainty evaluation in fish samples analyzed by INAA and AAS. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 521-528.

    Abstract: Measurement uncertainty was estimated following the EURACHEM guide (Quantifying Uncertainty in Analytical Measurement) for the elements As, Br, Cl, Co, Cr, Cs, Fe, K, Mg, Mn, Na, Rb, Sb, Se and Zn determined by Instrumental Neutron Activation Analysis (INAA) and for the elements Cd, Hg and Pb determined by Atomic Absorption Spectrometry (AAS) in the fillet of the most consumed fish species at São Paulo city, Brazil. INAA expanded uncertainties ranged from 1.0 to 21% and the main contributions were due the counting statistics of sample and pipetted standards. For AAS, expanded uncertainties ranged from 6.5 to 13% and the main contributions were associated to the calibration curves. Uncertainty results were compared with the standard deviations of the mass fraction in the fishes (n = 10). Due to the wide variability in the mass fraction in the analyzed fish tissues, explained by factors such gender, age, fat content and fishing location of the specimens of each specie, standard deviations were greater than expanded uncertainties, which means that the natural variability of the elements determined is greater than the data dispersion associate

    Palavras-Chave: absorption spectroscopy; brazil; data covariances; elements; evaluation; fishes; neutron activation analysis; toxicity

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  • IPEN-DOC 27629

    TAMURA, CAROLINE S. ; ARANTES, MARIANA ; CARMO, KARINA H.S. ; SANTOS, BIANCA S. ; OLIVEIRA, RENE R. ; MOURA, ESPERIDIANA A.B. . Mechanical and morphological properties of hybrid composites based on recycled LDPE/EVA blend reinforced with clay and babassu fiber residues. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 661-669, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_65

    Abstract: Over the years the consumption of plastic products made of conventional polymers has produced a large amount of waste which has led to disposal problems worldwide. Among the alternatives to minimize these problems are reuse and recycling practices. Then, the recycling of plastic and the use of recycled materials to produce new materials reinforced with nanoparticles from natural resources can be an alternative to reduce inappropriate waste disposal. The objective of this study is to investigate the effects of the addition of clay and non-treated babassu fiber residues on the mechanical and morphological properties of composite based on recycled LDPE/EVA blend. Composite materials containing 1–3 wt% of babassu residues and 1 wt% of clay were prepared using a twin-screw extruder machine and flat die single extrusion process, in order to prepare hybrid composites sheets. The sheets prepared by recycled LDPE/EVA blend and its composites were characterized by tensile tests, XRD, and FE-SEM analysis and the correlation between properties was discussed.

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  • IPEN-DOC 25801

    TAPPIZ, B. ; MOREIRA, E.G. . Neutron activation analysis characterization procedures for fish consumed at São Paulo city. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-9, 2019. DOI: 10.15392/bjrs.v7i2A.710

    Abstract: The characterization of edible tissues of fishes consumed by humans is very important for determination of sev-eral toxic and potentially toxic elements, ensuring the food safety. The Instrumental Neutron Activation Analysis (INAA) comparative method allows the determination of several of these elements, as well as others, for example of nutritional character. This study is part of an International Atomic Energy Agency (IAEA) technical coopera-tion project of Latin America and Caribbean countries to ensure the quality of food and biomonitoring of con-taminants in shellfish and fishes. Ten specimens of 4 of the most consumed fish in São Paulo city: whitemouth croaker (Micropogonias Furnieri), smooth weakfish (Cynoscion learchus), common snook (Centropomus undeci-malis) and Brazilian sardine (Sardinella brasiliensis) were analyzed. Complete procedures for analysis, which includes purchase in the largest warehouse in Latin America, transport to the laboratory, storage, freeze-drying, milling, weighting and others preparations of the subsamples, and the short irradiation parameters for the de-termination of Br, Cl, K, Mg, Mn and Na are reported. Results obtained under the same irradiation conditions for reference materials (oyster and mussel tissues) for macro and microelements are presented and are in agreement with their certificates, which indicate that the performed analyses were appropriate. Regarding to the mass fraction values obtained for the fish samples, they were in agreement with the literature.

    Palavras-Chave: neutron activation analysis; fishes; brazil; contamination; gamma spectroscopy; quality assurance; quality management; high-purity ge detectors; radioisotopes; food; quality control

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  • IPEN-DOC 27362

    SOUZA, CARLA D. de ; ZEITUNI, CARLOS A. ; FEHER, ANSELMO ; MOURA, JOÃO A. ; COSTA, OSVALDO L. da ; ANGELOCCI, LUCAS V. ; ROSTELATO, MARIA E.C.M. . New core configuration for the fabrication of 125I radioactive sources for cancer treatment. Applied Radiation and Isotopes, v. 165, p. 1-8, 2020. DOI: 10.1016/j.apradiso.2020.109307

    Abstract: In order to provide prostate brachytherapy treatment for more Brazilian men, IPEN is building a laboratory for the manufacture of radioactive sources. The new methodology for the production of iodine-125 seeds with yield 71.7% ± 5.3%. Points of importance were evaluated/discussed: photo-sensibility, reaction vial type, the substitution for iodine-131, pH, and solution volume. The surface was analyzed by FTIR and EDS. At the end, a Monte Carlo-MCNP6 simulation was performed to evaluate the TG-43 parameters.

    Palavras-Chave: radiation sources; iodine 125; brachytherapy; radiation chemistry; monte carlo method; neoplasms; tumor cells; prostate; iodination

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  • IPEN-DOC 24774

    PEREIRA, MARCO A.S. ; PUGLIESI, REYNALDO . Penetration of the consolidant Paraloid (R) B-72 in Macuxi indigenous ceramic vessels investigated by neutron tomography. Nuclear Instruments and Methods in Physics Research, A, v. 889, p. 118-121, 2018. DOI: 10.1016/j.nima.2018.02.034

    Abstract: The neutron tomography technique was applied in studying the penetration of the consolidant Paraloid (R) B-72 in contemporary indigenous ceramic vessels. The study was carried out for two distinct and controlled air humidity conditions, 40% and 90%, in which the vessels were exposed, before the consolidant application. The obtained images have proved that the penetration of Paraloid (R) B-72 in the ceramic does not depend on the humidity condition in which it was applied, moreover allowed a macro-visualization of the consolidant penetration in the ceramic vessel. As the vessels used in the present work were manufactured by an indigenous artisan, Macuxi, according to the same procedures and raw materials used by the ancient artisans, the results obtained can be used as a guide to assist experts, both in the study of archeological objects of Macuxi origin, as well as other objects that had been made by other tribes that lived in the same Amazon region, in Brazil.

    Palavras-Chave: neutrons; tomography; ceramics; biological recovery; cultural objects; humidity control; resins; indigenous peoples; brazil

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  • IPEN-DOC 24337

    COTA, STELA; HIROMOTO, GORO ; GHARBIEH, HEIDAR; SILVA, AURELIO. Preliminary post-closure safety assessment for a borehole-type repository for disused sealed radioactive sources in Brazil. Progress in Nuclear Energy, v. 103, p. 74-80, 2018. DOI: 10.1016/j.pnucene.2017.11.005

    Abstract: Brazil has a relatively large inventory of disused sealed radioactive sources (DSRSs). Until now, no decision has yet been made about the final destination of this category of radioactive wastes, although a repatriation of a small fraction of these sources comprising mainly neutron and high activity sources was already carried out. Borehole type repositories are one disposal solution considered for DSRSs in Brazil. This paper addresses a preliminary post-closure safety assessment for such a facility, using the borehole disposal concept (BDC) applied to different geological conditions and a range of projected inventories. Results from running the AMBER code considering deterministic and stochastic approaches showed that Am-241 is the main source of potential concern in order to comply with the effective dose constraint of 0.3 mSv/y and allowed the establishment of the relation between the maximum Am-241 inventory and the hydraulic conductivity of the geosphere.

    Palavras-Chave: safety; boreholes; brazil; abandoned shafts; radioactive wastes; sealed sources; radioactive waste disposal

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  • IPEN-DOC 27631

    COSTA, ROBSON S. ; ARAUJO, DANIELLE G. ; ANDRADE, MARCIO S. de; OLIVEIRA, RENE R. ; RANGARI, VIJAYA; MOURA, ESPERIDIANA A.B. ; DIAS, FRANCISCO V.. Production and characterization of PBAT reinforced with clay and graphene oxide nanosheets: a comparative study. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 689-699, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_68

    Abstract: The poly (butylene adipate-co-terephthalate) (PBAT), a biodegradable polymer, is among the most promising materials to be considered as environmentally friendly high performance biodegradable plastics. However, the mechanical properties of PBAT are not the best for several applications. According to the literature, the properties of the biodegradable polymer can be improved by addition of a small amount of nanofillers, such as clay, silica, and graphene. The objective of this study is to compare the effect of the addition of Cloisite clay and graphene oxide (GO) on the properties of flexible films based on PBAT matrix. The composite films based on PBAT with addition of Cloisite (2.0 wt%) and PBAT composite films with addition of Cloisite and GO (0.1–0.2 wt%) were prepared by extrusion, using a twin-screw extruder and a flat die single extruder. The effects of the addition of Cloisite clay and graphene oxide on mechanical and thermal properties of films were evaluated by mechanical and water absorption tests, FE-SEM, XRD, and Raman analysis.

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  • IPEN-DOC 27583

    LIMA, CAROLINE S.A. de ; VARCA, JUSTINE P.R.O. ; NOGUEIRA, KAMILA M. ; FAZOLIN, GABRIELA N. ; FREITAS, LUCAS F. de ; SOUZA, ELISEU W. de; LUGAO, ADEMAR B. ; VARCA, GUSTAVO H.C. . Semi-solid pharmaceutical formulations for the delivery of papain nanoparticles. Pharmaceutics, v. 12, n. 12, p. 1-12, 2020. DOI: 10.3390/pharmaceutics12121170

    Abstract: Papain is a therapeutic enzyme with restricted applications due to associated allergenic reactions. Papain nanoparticles have shown to be safe for biomedical use, although a method for proper drug loading and release remains to be developed. Thus, the objective of this work was to develop and assess the stability of papain nanoparticles in a prototype semi-solid formulation suitable for dermatological or topical administrations. Papain nanoparticles of 7.0 ± 0.1 nm were synthesized and loaded into carboxymethylcellulose- and poly(vinyl alcohol)-based gels. The formulations were then assayed for preliminary stability, enzyme activity, cytotoxicity studies, and characterized according to their microstructures and protein distribution. The formulations were suitable for papain nanoparticle loading and provided a stable environment for the nanoparticles. The enzyme distribution along the gel matrix was homogeneous for all the formulations, and the proteolytic activity was preserved after the gel preparation. Both gels presented a slow release of the papain nanoparticles for four days. Cell viability assays revealed no potential cytotoxicity, and the presence of the nanoparticles did not alter the microstructure of the gel. The developed systems presented a potential for biomedical applications, either as drug delivery systems for papain nanoparticles and/or its complexes.

    Palavras-Chave: papain; nanoparticles; drugs; gels; proteins

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  • IPEN-DOC 26883

    FAZOLIN, GABRIELA N. ; VARCA, GUSTAVO H.C. ; FREITAS, LUCAS F. de ; ROKITA, BOZENA; KADLUBOWSKI, SLAWOMIR; LUGAO, ADEMAR B. . Simultaneous intramolecular crosslinking and sterilization of papain nanoparticles by gamma radiation. Radiation Physics and Chemistry, v. 171, p. 1-7, 2020. DOI: 10.1016/j.radphyschem.2020.108697

    Abstract: Papain-based nanoparticles were recently developed using radiation technologies and proven effective to generate nanosized crosslinked papain particles with preserved enzymatic activity. The applications of such nanostructured systems are expected to be similar to native papain with considerable biopharmaceutical advantages and concern drug loading among other biotechnological applications. The nature of such crosslinks and the possibility to provide simultaneous sterilization have been hypothesized but remain not totally clarified. This manuscript advances the discussion on the radiation-induced synthesis of protein nanoparticles by approaching the nature of the crosslinking and the possible contribution of bityrosine linkages and disulfide bridges to the overall nanoparticle assembly as well as the feasibility of the simultaneous sterilization process under the preestablished conditions of processing. Papain nanoparticles were synthesized and characterized according to size, proteolytic activity, bityrosine, cysteine content and molecular weight by SDS-PAGE upon sonication at 40 kHz. Bacterial identification and the sterility tests were performed in accordance with ISO 11737 prior to and after inoculating 106 CFU of Corynebacterium xerosis. Our experiments evidenced the crosslinking of rather intra- than intermolecular nature and a contribution of cysteine bridges and bityrosine linkages to the stabilization and formation of the papain nanoparticle assembly. The technique was effective to promote simultaneous crosslinking and sterilization at the established conditions of processing and may be validated in accordance with the ISO 11137.

    Palavras-Chave: papain; sh-proteinases; nanoparticles; gamma radiation; proteins; cross-linking; sterilization; bacteria; disulfides

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  • IPEN-DOC 25091

    FAZOLIN, GABRIELA N. ; VARCA, GUSTAVO H.C. ; KADLUBOWSKI, SLAWOMIR; SOWINSKI, SEBASTIAN; LUGAO, ADEMAR B. . The effects of radiation and experimental conditions over papain nanoparticle formation: towards a new generation synthesis. Radiation Physics and Chemistry, v. 169, p. 1-8, 2020. DOI: 10.1016/j.radphyschem.2018.08.033

    Abstract: Papain is a natural enzyme extracted from the fruit of Carica papaya Linnaeus, successfully applied in the pharmaceutical area as a drug carrier and debridement agent for wounds. In recent studies papain nanoparticles were synthesized and crosslinked with the use of ionizing radiation in the search for biopharmaceutical advantages as well as the development of bioactive nanocarriers. This study addresses the effects of buffer molarity and irradiation conditions on papain nanoparticles formation. Nanoparticles were synthesized on ice bath using ethanol (20%, v/v) as a cosolvent and crosslinked by gamma radiation using a 60Co source. Experimental variables included the synthesis in deionized water and in 1, 10, 25 and 50mM phosphate buffer, under different temperatures of −20 °C, 0 °C and 20 °C before and throughout the irradiation period, and using radiation dose rates of 0.8, 2, 5 and 10 kGy h−1 to reach the dose of 10 kGy. Proteolytic activity was quantified using Nα- benzoyl-DL-arginine-p-nitroanilide hydrochloride. Nanoparticle size and crosslinking by means of bityrosine were evaluated by dynamic light scattering and fluorescence measurements, respectively. Buffer molarity and radiation dose rate were identified to influence bityrosine formation and proteolytic activity without impacting nanoparticle size. Variations in temperature impacted bityrosine formation exclusively. Optimized conditions for papain nanoparticle synthesis were achieved using 50mM phosphate buffer at the dose rate of 5 kGy h−1 and temperature of 0 °C throughout the process.

    Palavras-Chave: cobalt 60; cross-linking; dose rates; gamma radiation; irradiation; nanoparticles; papain; radiation doses; synthesis

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  • IPEN-DOC 25876

    MOURA, ESPERIDIANA A.B. . The potential of micro- and nano-sized fillers extracted from agroindustry residues as reinforcements of thermoplastic-based biocomposites: a review. In: IKHMAYIES, SHADIA (Ed.); LI, JIAN (Ed.); VIEIRA, CARLOS M.F. (Ed.); MARGEM, JEAN I. (Ed.); BRAGA, FABIO de O. (Ed.). Green Materials Engineering. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2019. p. 89-100, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-10383-5_10

    Abstract: Currently, the relevance of reuse of agroindustrial waste to obtain fillers in micro- and nano-sizes for the development of biocomposite materials has grown significantly. Production processes based on sustainable and low carbon development have increased interest in more environmentally friendly polymer composites, which have made the origin of reinforcement materials a determining factor for their application in this segment. This work presents a review of the developments of our team in the field of thermoplastic biocomposites reinforced with micro- and nano-sized fillers extracted from agroindustry residues. The different residues from Brazilian agroindustry available for the extraction of micro- and nano-sized fillers for the production of polymer biocomposites, the methods of the extraction and treatments of these natural fillers are presented; and its application as reinforcements in thermoplastic-based biocomposite are discussed in this review.

    Palavras-Chave: agriculture; agricultural wastes; environmental impacts; bagasse; biodegradation; thermoplastics; composite materials; fillers; polymers

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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.