Navegação por Revista "Scientific Reports"

Classificar por: Ordenar: Resultados:

  • IPEN-DOC 26419

    PRETTO, LUCAS R. de ; MOULT, ERIC M.; ALIBHAI, A.Y.; CARRASCO-ZEVALLOS, OSCAR M.; CHEN, SIYU; LEE, BYUNGKUN; WITKIN, ANDRE J.; BAUMAL, CAROLINE R.; REICHEL, ELIAS; FREITAS, ANDERSON Z. de ; DUKER, JAY S.; WAHEED, NADIA K.; FUJIMOTO, JAMES G.. Controlling for artifacts in widefield optical coherence tomography angiography measurements of non-perfusion area. Scientific Reports, v. 9, p. 1-15, 2019. DOI: 10.1038/s41598-019-43958-1

    Abstract: The recent clinical adoption of optical coherence tomography (OCT) angiography (OCTA) has enabled non-invasive, volumetric visualization of ocular vasculature at micron-scale resolutions. Initially limited to 3 mm × 3 mm and 6 mm × 6 mm fields-of-view (FOV), commercial OCTA systems now offer 12 mm × 12 mm, or larger, imaging fields. While larger FOVs promise a more complete visualization of retinal disease, they also introduce new challenges to the accurate and reliable interpretation of OCTA data. In particular, because of vignetting, wide-field imaging increases occurrence of low-OCT-signal artifacts, which leads to thresholding and/or segmentation artifacts, complicating OCTA analysis. This study presents theoretical and case-based descriptions of the causes and effects of low-OCTsignal artifacts. Through these descriptions, we demonstrate that OCTA data interpretation can be ambiguous if performed without consulting corresponding OCT data. Furthermore, using wide-field non-perfusion analysis in diabetic retinopathy as a model widefield OCTA usage-case, we show how qualitative and quantitative analysis can be confounded by low-OCT-signal artifacts. Based on these results, we suggest methods and best-practices for preventing and managing low-OCT-signal artifacts, thereby reducing errors in OCTA quantitative analysis of non-perfusion and improving reproducibility. These methods promise to be especially important for longitudinal studies detecting progression and response to therapy.

    Palavras-Chave: ophthalmology; retina; biomedical radiography; tomography; vascular diseases; optical equipment; coherent radiation; images; blood vessels; beam scanners

    Icon

  • IPEN-DOC 25775

    RAELE, MARCUS P. ; DE PRETTO, LUCAS R. ; ROSSI, WAGNER de ; VIEIRA JUNIOR, NILSON D. ; SAMAD, RICARDO E. . Focus tracking system for femtosecond laser machining using low coherence interferometry. Scientific Reports, v. 9, p. 1-8, 2019. DOI: 10.1038/s41598-019-40749-6

    Abstract: We designed a real time, single-laser focus tracking system using low coherence properties of the machining femtosecond laser itself in order to monitor and correct the sample position relative to the focal plane. Using a Michelson Interferometer, the system collects data arising from part of the beam backscattered at the ablation spot. The data is analyzed by a custom software for position correction (employing an XYZ automated translation stage). With the focus tracking enabled we were able to etch channels with a stable cross-section profile on a bovine tooth with relief amplitude tens of times greater than the Rayleigh length of the system, keeping the sample inside the confocal parameter during most of the processing time. Moreover, the system is also capable of monitoring crater depth evolution during the ablation process, allowing for material removal assessment.

    Palavras-Chave: interferometry; laser radiation; michelson interferometer; laser beam machining; ablation; optical systems

    Icon

  • IPEN-DOC 26445

    LEMOS, F.S.; PEREIRA, J.X.; CARVALHO, V.F.; BERNARDES, E.S. ; CHAMMAS, R.; PEREIRA, T.M.; CARVALHO, R.S.; LUISETTO, R.; EL-CHEIKH, M.C.; CALIL-ELIAS, S.; OLIVEIRA, F.L.. Galectin-3 orchestrates the histology of mesentery and protects liver during lupus-like syndrome induced by pristane. Scientific Reports, v. 9, 2019. DOI: 10.1038/s41598-019-50564-8

    Abstract: Galectin-3 (Gal-3) controls intercellular and cell-extracellular matrix interactions during immunological responses. In chronic inflammation, Gal-3 is associated with fibrotic events, regulates B cell differentiation and delays lupus progression. Gal-3 deficient mice (Lgals3−/−) have intense germinal center formation and atypical plasma cell generation correlated to high levels IgG, IgE, and IgA. Here, we used pristane (2,6,10,14-tetramethylpentadecane) to induce lupus-like syndrome in Lgals3−/− and Lgals3+/+ BALB/c mice. Mesentery and peritoneal cells were monitored because promptly react to pristane injected in the peritoneal cavity. For the first time, mesenteric tissues have been associated to the pathogenesis of experimental lupus-like syndrome. In Lgals3+/+ pristane-induced mice, mesentery was hallmarked by intense fibrogranulomatous reaction restricted to submesothelial regions and organized niches containing macrophages and B lymphocytes and plasma cells. In contrast, Lgals3−/− pristane-treated mice had diffuse mesenteric fibrosis affecting submesothelium and peripheral tissues, atypical M1/M2 macrophage polarization and significant DLL1+ cells expansion, suggesting possible involvement of Notch/Delta pathways in the disease. Early inflammatory reaction to pristane was characterized by significant disturbances on monocyte recruitment, macrophage differentiation and dendritic cell (DC) responses in the peritoneal cavity of pristane-induced Lgals3−/− mice. A correlative analysis showed that mesenteric damages in the absence of Gal-3 were directly associated with severe portal inflammation and hepatitis. In conclusion, it has suggested that Gal-3 orchestrates histological organization in the mesentery and prevents lupoid hepatitis in experimental lupus-like syndrome by controlling macrophage polarization, Notch signaling pathways and DC differentiation in mesenteric structures.

    Palavras-Chave: proteins; lectins; immunology; cytochemistry; biochemical reaction kinetics; blood cells; hematologic agents; immune reactions

    Icon

  • IPEN-DOC 21269

    RIVALDO GOMEZ, C.M.; CABRERA PASCA, G.A.; ZUNIGA, A.; CARBONARI, A.W. ; SOUZA, J.A.. Hierarchically structured nanowires on and nanosticks in ZnO microtubes. Scientific Reports, v. 5, 2015.

    Palavras-Chave: nanowires; zinc ions; nanostructures; oxides; semiconductor materials; magnetic semiconductors; coaxial cables

    Icon

  • IPEN-DOC 25114

    MATOS, BRUNO R. ; POLITANO, RODOLFO ; REY, JOSE F.Q.; HERMIDA-MERINO, DANIEL; SCHADE, ULRICH; PUSKAR, LJILJANA; FONSECA, FABIO C. . Interplay of alpha/beta-relaxation dynamics and the shape of ionomer building blocks. Scientific Reports, v. 8, n. 13441, 2018. DOI: 10.1038/s41598-018-31368-8

    Abstract: The relation between the alpha/beta relaxations and the shape of the building blocks of ionomer materials is a key factor for programming an important temperature-dependent property: the memory of shape. However, the morphology of ionomers is indirectly obtained via modeling of small angle X-ray scattering (SAXS) data owing to the hardly accessible image characterization of the nanometric building blocks-micelle-like cylindrical polymeric aggregates (radius similar to 2-6 nm and length >100 nm). Herein, broadband dielectric spectroscopy (BDS) measurements, free from electrode polarization effects, allowed identifying the time and temperature dependence of the polarization of different length scales of the ionomer matrix, and more importantly, by directly providing the aspect ratio of the radius and length of the polymeric aggregates for each desired temperature. This finding is essential for controlling the shape of ionomer based functional products under several stimuli conditions, thereby advancing remarkable applications, such as four dimensional (4D) printing.

    Palavras-Chave: polymers; simulation; morphological changes; small angle scattering; relaxation; x radiation

    Icon

  • IPEN-DOC 24767

    OLIVEIRA, FELIPE L. de; SANTOS, SOFIA N. dos ; RICON, LAUREMILIA; COSTA, THAYSE P. da; PEREIRA, JONATHAS X.; BRAND, CAMILA; FERMINO, MARISE L.; CHAMMAS, ROGER; BERNARDES, EMERSON S. ; EL-CHEIKH, MARCIA C.. Lack of galectin-3 modifies differentially Notch ligands in bone marrow and spleen stromal cells interfering with B cell differentiation. Scientific Reports, v. 8, n. 3495, p. 1-14, 2018. DOI: 10.1038/s41598-018-21409-7

    Abstract: Galectin-3 (Gal-3) is a beta-galactoside binding protein that controls cell-cell and cell-extracellular matrix interactions. In lymphoid organs, gal-3 inhibits B cell differentiation by mechanisms poorly understood. The B cell development is dependent on tissue organization and stromal cell signaling, including IL-7 and Notch pathways. Here, we investigate possible mechanisms that gal-3 interferes during B lymphocyte differentiation in the bone marrow (BM) and spleen. The BM of gal-3-deficient mice (Lgals3(-/-)mice) was evidenced by elevated numbers of B220(+)CD19(+)c-Kit(+)IL-7R(+) progenitor B cells. In parallel, CD45-bone marrow stromal cells expressed high levels of mRNA IL-7, Notch ligands (Jagged-1 and Delta-like 4), and transcription factors (Hes-1, Hey-1, Hey-2 and Hey-L). The spleen of Lgals3(-/-)mice was hallmarked by marginal zone disorganization, high number of IgM(+) IgD(+) B cells and CD138(+)plasma cells, overexpression of Notch ligands (Jagged-1, Delta-like 1 and Delta-like 4) by stromal cells and Hey-1. Morever, IgM(+) IgD(+) B cells and B220(+)CD138(+)CXCR4(+) plasmablasts were significantly increased in the BM and blood of Lgals3(-/-)mice. For the first time, we demonstrated that gal-3 inhibits Notch signaling activation in lymphoid organs regulating earlier and terminal events of B cell differentiation.

    Palavras-Chave: galactose; lymph nodes; bone marrow cells; spleen cells; ligands; cell proliferation

    Icon

  • IPEN-DOC 26879

    SANTOS, NATHALIA V. dos; VIEIRA, CAROLINA L.Z.; SALDIVA, PAULO H.N.; MAZZILLI, BARBARA P. ; SAIKI, MITIKO ; SAUEIA, CATIA H. ; DE ANDRE, CARMEN D.S.; JUSTO, LISIE T.; NISTI, MARCELO B. ; KOUTRAKIS, PETROS. Levels of Polonium-210 in brain and pulmonary tissues: preliminary study in autopsies conducted in the city of São Paulo, Brazil. Scientific Reports, v. 10, n. 1, p. 1-7, 2020. DOI: 10.1038/s41598-019-56973-z

    Abstract: The accumulation of detectable amounts of radon progeny in human tissues may be a risk factor for development and progression of chronic diseases. In this preliminary study, we analyzed the levels of alpha-emitting radon progeny Polonium-210 (210Po) in the olfactory epithelium, olfactory bulb, frontal lobe, and lung tissues in cadavers from the city of Sao Paulo, SP, Brazil. We also assessed the association between 210Po levels and exposure parameters for urban air pollution using linear regression models adjusted for age, sex, smoke, time living in Sao Paulo, daily commuting, socioeconomic index, and anthracosis (traffic-related black carbon accumulation in the pleural region and in lymph). Our findings show that the concentration of 210Po was associated with anthracosis in lungs of nonsmokers (coefficient = 6.0; standard error = 2.9; p = 0.04). Individuals with lower socioeconomic status also had significantly higher 210Po levels in lungs (coefficient = −1.19; standard error = 0.58; p = 0.042). The olfactory bulb had higher 210Po levels than either olfactory epithelium (p = 0.071), frontal lobe (p < 0.001), or lungs (p = 0.037). Our findings of the deposition of 210Po in autopsy tissues suggest that airborne radionuclides may contribute to the development of chronic diseases, including neurodegenerative diseases.

    Palavras-Chave: body composition; autopsy; polonium 210; progeny; radon; animal tissues; lungs; brain; epithelium; tobacco smokes; air pollution; human populations; urban populations; brazil

    Icon

  • IPEN-DOC 25095

    GENARO, ISABELLA S. de; ALMEIDA, FRANCINE M. de; HIZUME-KUNZLER, DEBORAH C.; MORIYA, HENRIQUE T.; SILVA, RONALDO A.; CRUZ, JOAO C.G.; LOPES, RENAN B.; RIGHETTI, RENATO F.; VIEIRA, RODOLFO de P.; SAIKI, MITIKO ; MARTINS, MILTON A.; TIBERIO, IOLANDA de F.L.C.; ARANTES-COSTA, FERNANDA M.; SARAIVA-ROMANHOLO, BEATRIZ M.. Low dose of chlorine exposure exacerbates nasal and pulmonary allergic inflammation in mice. Scientific Reports, v. 8, n. 12636, 2018. DOI: 10.1038/s41598-018-30851-6

    Observação: Author Correction anexado. Scientific Reports, v. 8, p. 1, 2018. DOI: 10.1038/s41598-018-36667-8

    Abstract: Work-exacerbated asthma (WEA) is defined as preexisting asthma that worsens with exposure to irritants [e.g., chlorine (Cl2) derivatives] in the workplace. The maximum allowable concentration in the workplace of Cl2 exposure is 3 mg/ m3 (described in OSHA). We investigated in an experimental asthma model in mice the effects of a single exposure to a sodium hypochlorite dose with this allowed chlorine concentration and a tenfold higher dose. Acute chlorine exposure at 3.3 mg/m3 in the OVA-sensitized group increased eosinophils in the peribronquial infiltrate, cytokine production, nasal mucus production and the number of iNOS positive cells in the distal lung compared to only sensitized mice. The exposure to a higher dose of 33.3 mg/m3 in the OVA-sensitized group resulted in an increase in respiratory system elastance, in the total and differential numbers of inflammatory cells in bronchoalveolar lavage fluid, IL-4, IL-5, and IL-17 in the lungs, eosinophils in peribronquial infiltrate and mucus content in nasal compared to non-exposed and sensitized animals. In this asthma model, chorine exposures at an allowable dose, contributed to the potentiation of Th2 responses. The functional alterations were associated with increased iNOS and ROCK-2 activation in the distal lung.

    Palavras-Chave: chlorine; allergy; inflammation; lymphokines; nose; sinuses; respiratory system diseases; asthma

    Icon

  • IPEN-DOC 20930

    MAIA, FRANCISCO C.B.; SAMAD, RICARDO E. ; BETTINI, JEFFERSON; FREITAS, RAUL O.; VIEIRA JUNIOR, NILSON D. ; SOUZA-NETO, NARCIZO M.. Synthesis of diamond-like phase from graphite by ultrafast laser driven dynamical compression. Scientific Reports, v. 5, p. 1-6, 2015.

    Palavras-Chave: environment; laser radiation; pulses; carbon; allotropy; graphite; diamonds

    Icon

  • IPEN-DOC 27592

    DIAZ, JULIO C.C.A. ; M'PEKO, JEAN-CLAUDE; VENET, MICHEL; SILVA JUNIOR, PAULO S. da. Unveiling the high‑temperature dielectric response of Bi0.5Na0.5TiO3. Scientific Reports, v. 10, n. 1, p. 1-11, 2020. DOI: 10.1038/s41598-020-75859-z

    Abstract: Understanding the physics behind changes in dielectric permittivity and mechanical response with temperature and frequency in lead-free ferroic materials is a fundamental key to achieve optimal properties and to guarantee good performance in the technological applications envisaged. In this work, dense Bi0.5Na0.5TiO3 (BNT) electroceramics were prepared through solid-state reaction of highgrade oxide reagents, followed by sintering at high temperature (1393 K for 3 h). In good agreement with previous reports in the literature, the thermal behaviour of dielectric response from these BNT materials showed the occurrence of a high-temperature diffuse-like permittivity peak, whose origin has been so far controversial. Thermally stimulated depolarization current, impedance and mechanical spectroscopies measurements were here conducted, over a wide range of temperature and frequency, to get a deep insight into the mechanism behind of this event. The approach included considering both as-sintered and reduced BNT samples, from which it is demonstrated that the broad high-temperature dielectric peak originates from interfacial polarization involving oxygen vacancies-related spacecharge effects that develop at the grain-to-grain contacts. This mechanism, that contributes to the anomalous behavior observed in the mechanical response at low frequencies, could also be responsible for the presence of ferroelastic domains up to high temperatures.

    Palavras-Chave: lead compounds; titanates; zirconium compounds; ceramics; thermal analysis; impedance

    Icon

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.