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  • IPEN-DOC 25112

    MARIANO, DOUGLAS O.C.; MESSIAS, MARCELA Di G. ; PREZOTTO-NETO, JOSE P. ; SPENCER, PATRICK J. ; PIMENTA, DANIEL C.. Biochemical analyses of proteins from duttaphrynus melanostictus (Bufo melanostictus) skin secretion: soluble protein retrieval from a viscous matrix by ion-exchange batch sample preparation. Protein Journal, v. 37, n. 4, p. 380-389, 2018. DOI: 10.1007/s10930-018-9780-z

    Abstract: A crucial step in scientific analysis can be sample preparation, and its importance increases in the same rate as the sensitivity of the following employed/desired analytical technique does. The need to analyze complex, viscous matrices is not new, and diverse approaches have been employed, with different success rates depending on the intended molecules. Solid-phase extraction, for example, has been successfully used in sample preparation for organic molecules and peptides. However, due to the usual methodological conditions, biologically active proteins are not successfully retrieved by this technique, resulting in a low rate of protein identification reported for the viscous amphibian skin secretion. Here we describe an ion-exchange batch processing sample preparation technique that allows viscous or adhesive materials (as some amphibian skin secretions) to be further processed by classical liquid chromatography approaches. According to our protocol, samples were allowed to equilibrate with a specific resin that was washed with appropriated buffers in order to yield the soluble protein fraction. In order to show the efficiency of our methodology, we have compared our results to classically prepared skin secretion, i.e., by means of filtration and centrifugation. After batch sample preparation, we were able to obtain reproductive resolved protein chromatographic profiles, as revealed by SDS-PAGE, and retrieve some biological activities, namely, hydrolases belonging to serine peptidase family. Not only that, but also the unbound fraction was rich in low molecular mass molecules, such as alkaloids and steroids, making this sample preparation technique also suitable for the enrichment of such molecules.

    Palavras-Chave: chromatography; ion exchange chromatography; animal tissues; secretion; skin; sample preparation; viscosity; amphibians; hydrolases


  • IPEN-DOC 26413

    COELHO, GUILHERME R.; PREZOTTO NETO, PEDRO ; BARBOSA, FERNANDA C.; SANTOS, RAFAEL S. dos; BRIGATTE, PATRICIA; SPENCER, PATRICK J. ; SAMPAIO, SANDRA C.; D’AMELIO, FERNANDA; PIMENTA, DANIEL C.; SCIANI, JULIANA M.. Biochemical and biological characterization of the Hypanus americanus mucus: a perspective on stingray immunity and toxins. Fish and Shellfish Immunology, v. 93, p. 832-840, 2019. DOI: 10.1016/j.fsi.2019.08.049

    Abstract: Stingrays skin secretions are largely studied due to the human envenoming medical relevance of the sting puncture that evolves to inflammatory events, including necrosis. Such toxic effects can be correlated to the biochemical composition of the sting mucus, according to the literature. Fish skin plays important biological roles, such as the control of the osmotic pressure gradient, protection against mechanical forces and microorganism infections. The mucus, on the other hand, is a rich and complex fluid, acting on swimming, nutrition and the innate immune system. The elasmobranch's epidermis is a tissue composed mainly by mucus secretory cells, and marine stingrays have already been described to present secretory glands spread throughout the body. Little is known about the biochemical composition of the stingray mucus, but recent studies have corroborated the importance of mucus in the envenomation process. Aiming to assess the mucus composition, a new noninvasive mucus collection method was developed that focused on peptides and proteins, and biological assays were performed to analyze the toxic and immune activities of the Hypanus americanus mucus. Pathophysiological characterization showed the presence of peptidases on the mucus, as well as the induction of edema and leukocyte recruitment in mice. The fractionated mucus improved phagocytosis on macrophages and showed antimicrobial activity against T. rubrumç. neoformans and C. albicans in vitro. The proteomic analyses showed the presence of immune-related proteins like actin, histones, hemoglobin, and ribosomal proteins. This protein pattern is similar to those reported for other fish mucus and stingray venoms. This is the first report depicting the Hypanus stingray mucus composition, highlighting its biochemical composition and importance for the stingray immune system and the possible role on the envenomation process.

    Palavras-Chave: fishes; skin; secretion; animal tissues; hazardous materials; venoms; proteins; biochemistry; antimicrobial agents; biological materials; immune reactions; immunity


  • IPEN-DOC 27822

    SARTORI, GISELLE P.; COSTA, ANDREA da; MACARINI, FERNANDO L. dos S.; MARIANO, DOUGLAS O.C.; PIMENTA, DANIEL C.; SPENCER, PATRICK J. ; NALI, LUIZ H. da S.; GALISTEO JUNIOR, ANDRES J.. Characterization and evaluation of the enzymatic activity of tetanus toxin submitted to cobalt-60 gamma radiation. Journal of Venomous Animals and Toxins including Tropical Diseases, v. 27, p. 1-13, 2021. DOI: 10.1590/1678-9199-JVATITD-2020-0140

    Abstract: Background Tetanus toxin blocks the release of the inhibitory neurotransmitters in the central nervous system and causes tetanus and its main form of prevention is through vaccination. The vaccine is produced by inactivation of tetanus toxin with formaldehyde, which may cause side effects. An alternative way is the use of ionizing radiation for inactivation of the toxin and also to improve the potential immunogenic response and to reduce the post-vaccination side effects. Therefore, the aim of this study was to characterize the tetanus toxin structure after different doses of ionizing radiation of 60Co. Methods Irradiated and native tetanus toxin was characterized by SDS PAGE in reducing and non-reducing conditions and MALD-TOF. Enzymatic activity was measured by FRET substrate. Also, antigenic properties were assessed by ELISA and Western Blot data. Results Characterization analysis revealed gradual modification on the tetanus toxin structure according to doses increase. Also, fragmentation and possible aggregations of the protein fragments were observed in higher doses. In the analysis of peptide preservation by enzymatic digestion and mass spectrometry, there was a slight modification in the identification up to the dose of 4 kGy. At subsequent doses, peptide identification was minimal. The analysis of the enzymatic activity by fluorescence showed 35 % attenuation in the activity even at higher doses. In the antigenic evaluation, anti-tetanus toxin antibodies were detected against the irradiated toxins at the different doses, with a gradual decrease as the dose increased, but remaining at satisfactory levels. Conclusion Ionizing radiation promoted structural changes in the tetanus toxin such as fragmentation and/or aggregation and attenuation of enzymatic activity as the dose increased, but antigenic recognition of the toxin remained at good levels indicating its possible use as an immunogen. However, studies of enzymatic activity of tetanus toxin irradiated with doses above 8 kGy should be further analyzed.


  • IPEN-DOC 26354

    SILVA, MARCONES C.B. da ; SCHOTT, SANDRO M.C. ; MESQUITA, ROBERTO N. de . Development of a real-time focus estimaton software to be applied in two-phase flow imaging using intelligent processing. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 21-25, 2019, Santos, SP. Proceedings... Rio de Janeiro: Associação Brasileira de Energia Nuclear, 2019. p. 4887-4902.

    Abstract: Image processing has been an increasing research area in the last decades, especially due to crescent technological growth allied with lowering production costs. Many scientific applications have searched for establishment of quality norms associated with possible information obtainment from images. A common need from different applications has been the standardization of focus quality metric. The development of new methods for measuring the focus adjustment in order to obtain image quality metric analysis has enabled more reliable and precise data in many different industry and science sectors. Some examples are industrial equipment parts inspection using computational vision to defects classification. This work presents the initial steps to develop a methodology to estimate focus in real time in two-phase flow experiments inside tube with cylindrical geometry. This methodology is initially based on a software module using artificial intelligence methods to estimate image focus. This module is developed in LabVIEW platform using Fuzzy Logic inference base in different traditional digital focus metrics and integrated with digital cameras to increment precision on focus adjustment during two-phase flow experiments. This method will be calibrated to be used on void fraction estimation through image analysis in the natural circulation loop located at the Nuclear Engineering Center (CEN) do Instituto de Pesquisas Energéticas e Nucleares (IPEN). A set of the initial developed software modules will be presented with their respective functionalities, initial results and experimental focus estimated errors.

    Palavras-Chave: artificial intelligence; defects; focusing; focusing; fuzzy logic; image processing; l codes; m codes; natural convection; quality assurance; real time systems; tubes; two-phase flow; void fraction; brazilian cnen


  • IPEN-DOC 25783

    DAGUANO, JULIANA K.M.B.; MILESI, MARIANA T.B.; RODAS, ANDREA C.D.; WEBER, ALINE F.; SARKIS, JORGE E.S. ; HORTELLANI, MARCOS A. ; ZANOTTO, EDGAR D.. In vitro biocompatibility of new bioactive lithia-silica glass-ceramics. Materials Science & Engineering C, v. 94, p. 117-125, 2019. DOI: 10.1016/j.msec.2018.09.006

    Abstract: Glass-ceramics based on the Li2O-SiO2 system have been extensively used as restorative dental materials due to their excellent chemical durability, aesthetics, inertness in the buccal environment, and high fracture strength; but they are not bioactive. On the other hand, all known bioactive glasses show ability to bond to bone, teeth and cartilage coupled to osteoconduction and osteoinduction, but their fracture strength and toughness are rather low. The aim of this study is to develop and evaluate the in vitro biocompatibility of a new type of (bioactive and strong) lithia-silica glass-ceramic. For these purposes, two types of glass-ceramics based on a multicomponent lithia-silica system were studied: lithium metasilicate (LM) and lithium disilicate (LD). The in vitro bioactivity study was conducted in a SBF solution, before and after different times of immersion; the new materials were analyzed by XRD, FTIR, and SEM. Some samples were subjected to in vitro biodegradation tests to quantify the release of lithium and the weight loss. Cytotoxicity, adhesion, and cell proliferation on different samples were examined by using the Methyl Tetrazolium salt (MTS) and Alizarin Red. For ~40 vol% crystallinity, lithium metasilicate was detected as the major phase, whereas for ~80 vol% crystallinity, lithium disilicate was the major phase. The LD proved to be strong (3p-bending strength of 233 ± 12 MPa) and bioactive after 14 days of immersion in SBF. In terms of lithium ion release, the LD was outside the toxic range (> 8.3 ppm). The LM and LD are not cytotoxic. The LD shows the best cellular adhesion and proliferation, leading to the formation of a mineralized matrix after 21 days. These results clearly suggest that the new LD brand is strong and highly biocompatible and warrants further study.

    Palavras-Chave: biology; compatibility; dentistry; teeth; biological regeneration; in vitro; crystallization; lithium; ceramics; glass


  • IPEN-DOC 24819

    OLIVEIRA, MARA C.L. de; CORREA, OLANDIR V. ; ETT, BARDIA; SAYEG, ISAAC J.; LIMA, NELSON B. de ; ANTUNES, RENATO A.. Influence of the tungsten content on surface properties of electroless Ni-W-P coatings. Materials Research, v. 21, n. 1, p. 1-13, 2018. DOI: 10.1590/1980-5373-MR-2017-0567

    Abstract: Ternary Ni-W-P films were produced by electroless deposition using baths with different tungsten concentrations. After deposition, the coated surfaces were annealed at 400°C for 1h. Surface morphology and film composition in the as-plated condition were assessed by SEM and EDS analyses, respectively. The crystalline phases after annealing were investigated by X-ray diffraction (XRD). Nanoindentation tests were performed to assess the mechanical properties of the deposited films. Surface roughness was determined by confocal laser scanning microscopy (CLSM). Friction coefficient was evaluated by reciprocating were tests in a nanotribometer. The corrosion behavior was evaluated by potentiodynamic polarization curves. The results showed that the surface morphology, crystallization behavior and corrosion resistance were affected by the tungsten content in the film. The best corrosion performance was obtained for the ternary films after annealing. Hardness, surface roughness and friction coefficient were dependent of the tungsten concentration in the film.

    Palavras-Chave: chemical analysis; coatings; corrosion resistance; deposition; films; mechanical properties; nickel; phosphorus; scanning electron microscopy; surface properties; tungsten; x-ray diffraction


  • IPEN-DOC 27255


    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.

    Palavras-Chave: nuclear matrix; neutrons; modulation; silver nitrates; calculation methods; neutron beams; charge exchange


  • IPEN-DOC 25830

    SCIANI, JULIANA M.; NEVES, ADRIANA; VASSÃO, RUTH C.; SPENCER, PATRICK ; ANTONIAZZI, MARTA M.; JARED, CARLOS; PIMENTA, DANIEL C.. The amphibian diacylglycerol O-acyltransferase 2 (DGAT2): a ‘paleoprotein’ with conserved function but unique folding. Protein Journal, v. 38, n. 1, p. 83-94, 2019. DOI: 10.1007/s10930-019-09814-x

    Abstract: Amphibians are, currently, considered the first vertebrates that had performed the aquatic to terrestrial transition during evolution; therefore, water balance and dehydration control were prerequisites for such environment conquering. Among anurans, Phyllomedusa is a well-studied genus, due to its peptide-rich skin secretion. Here, we have analyzed the skin secretion of Phyllomedusa distincta targeting the proteins present in the skin secretion. The major soluble protein was chromatographically isolated and utilized to immunize rabbits. Through proteomics approaches, we were able to identify such protein as being the diacylglycerol O-acyltransferase 2 (DGAT2), a crucial enzyme involved in lipid synthesis and in the skin water balance. Immunohistochemistry assays revealed the protein tissular distribution for different animal species, belonging to different branches of the phylogenetic tree. Specifically, there was positivity to the anti-DGAT2 on Amphibians’ skin, and no antibody recognition on fish and mammals’ skins. The DGAT2 multiple sequence alignment reveals some degree of conservation throughout the genera; however, there is a different cysteine pattern among them. Molecular modeling analyses corroborate that the different cysteine pattern leads to distinct 3D structures, explaining the different antibody recognition. Moreover, the protein phylogenetic analyses place the Xenopus DGAT2 (the available amphibian representative) next to the Coelacanthus enzyme, which have led the authors to term this a ‘paleo-protein’. DGAT2 would be, therefore, an ancient protein, crucial to the terrestrial environment conquest, with a unique folding—as indicated by the molecular models and immunohistochemistry analyses—a consequence of the different cysteine pattern but with conserved biological function.

    Palavras-Chave: amphibians; peptides; skin; proteins; secretion; chemical analysis; temperature control


  • IPEN-DOC 25565

    SERRA, PEDRO L.S.; MASOTTI, PAULO H.F. ; ROCHA, MARCELO S. ; ANDRADE, DELVONEI A. de ; TORRES, WALMIR M. ; MESQUITA, ROBERTO N. de . Two-phase flow void fraction estimation based on bubble image segmentation using Randomized Hough Transform with Neural Network (RHTN). Progress in Nuclear Energy, v. 118, p. 1-21, 2020. DOI: 10.1016/j.pnucene.2019.103133

    Abstract: The International Atomic Energy Agency (IAEA) has been encouraging the use of passive cooling systems in new designs of nuclear power plants. Next nuclear reactor generations are intended to have simpler and robust safety resources. Natural Circulation based systems hold an undoubtedly prominent position among these. The study of limiting conditions of these systems has led to instability behavior analysis where many different two-phase flow patterns are present. Void fraction is a key parameter in thermal transfer analysis of these flow instability conditions. This work presents a new method to estimate void fraction from images captured of an experimental two-phase flow circuit. The method integrates a set of Artificial Neural Networks with a modified Randomized Hough Transform to make multiple scans over acquired images, using crescent-sized masks. This method was called Randomized Hough Transform with Neural Network (RHTN). Each different mask size is chosen according with bubble sizes, which are the main ‘objects of interest’ in this image analysis. Images are segmented using fuzzy inference with different parameters adjusted based on acquisition focus. Void fraction calculation considers the volume of the imaged geometrical section of flow inside cylindrical glass tubes considering the acquisition depth-of-field used. The bubble volume is estimated based on geometrical parameters inferred for each detected bubble. The image database is obtained from experiments performed on a vertical two-phase flow circuit made of cylindrical glass where flow-patterns visualization is possible. The results have shown that the estimation method had good agreement with increasing void fraction experimental values. RHTN has been very efficient as bubble detector with very low ‘false-positive’ cases (< 0.004%) due robustness obtained through integration between Artificial Neural Networks with Randomized Hough Transforms.

    Palavras-Chave: two-phase flow; void fraction; neural networks; image processing; bubbles; fuzzy logic; transformations; nuclear power plants; pattern recognition; natural convection; randomness


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.


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, .

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).



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.