Navegação Periódicos - Artigos por autor "9803"

Classificar por: Ordenar: Resultados:

  • 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

    Icon

  • IPEN-DOC 27384

    COUTO, VERONICA M.; OLIVEIRA-NASCIMENTO, LAURA de; CABEÇA, LUIZ F.; GERALDES, DANILO C.; COSTA, JULIANA S.R.; RISKE, KARIN A.; FRANZ-MONTAN, MICHELLE; YOKAYCHIYA, FABIANO ; FRANCO, MARGARETH K.K.D. ; PAULA, ENEIDA de. Capsaicin-cyclodextrin complex enhances mepivacaine targeting and improves local anesthesia in inflamed tissues. International Journal of Molecular Sciences, v. 21, n. 16, p. 1-18, 2020. DOI: 10.3390/ijms21165741

    Abstract: Acidic environments, such as in inflamed tissues, favor the charged form of local anesthetics (LA). Hence, these drugs show less cell permeation and diminished potency. Since the analgesic capsaicin (CAP) triggers opening of the TRPV1 receptor pore, its combination with LAs could result in better uptake and improved anesthesia. We tested the above hypothesis and report here for the first time the analgesia effect of a two-drug combination (LA and CAP) on an inflamed tissue. First, CAP solubility increased up to 20 times with hydroxypropyl-beta-cyclodextrin (HP-β-CD), as shown by the phase solubility study. The resulting complex (HP-β-CD-CAP) showed 1:1 stoichiometry and high association constant, according to phase-solubility diagrams and isothermal titration calorimetry data. The inclusion complex formation was also confirmed and characterized by differential scanning calorimetry (DSC), X-ray diffraction, and 1H-NMR. The freeze-dried complex showed physicochemical stability for at least 12 months. To test in vivo performance, we used a pain model based on mouse paw edema. Results showed that 2% mepivacaine injection failed to anesthetize mice inflamed paw, but its combination with complexed CAP resulted in pain control up to 45 min. These promising results encourages deeper research of CAP as an adjuvant for anesthesia in inflamed tissues and cyclodextrin as a solubilizing agent for targeting molecules in drug delivery.

    Palavras-Chave: anesthesia; inflammation; anesthetics; dextrin; scanning electron microscopy; differential thermal analysis; calorimetry

    Icon

  • IPEN-DOC 26865

    BEZAMAT, JULIANA M.; YOKAICHIYA, FABIANO ; FRANCO, MARGARETH K.K.D. ; CASTRO, SIMONE R.; PAULA, ENEIDA de; CABEÇA, LUIS F.. Complexation of the local anesthetic pramoxine with hydroxypropyl-beta-cyclodextrin can improve its bioavailability. Journal of Drug Delivery Science and Technology, v. 55, p. 1-8, 2020. DOI: 10.1016/j.jddst.2019.101475

    Abstract: Local anesthetics are widely used in clinical procedures, to eliminate pain during/after invasive procedures. A wide range of drug delivery systems has been developed to improve the effect of local anesthetics and/or to reduce their toxicity. Pramoxine (PMX) is a topical anesthetic agent with an unusual (morpholine ring) structure and low solubility (ca. 3 mM at pH 7.4). In this work, a novel formulation was devised for PMX in hydroxypropyl- β-cyclodextrin (HP-β-CD). Host-guest inclusion complex was prepared by the co-solubilization method, with complexation kinetics of 10 h, and 1:1 PMX/HP-β-CD stoichiometry. Complexation promoted 14-fold increase in the solubility of PMX. X-ray diffraction measurements revealed loss of the crystalline PMX pattern in the presence of HP-β-CD, an indication of inclusion complexation. Using 1H NMR (DOSY) experiments the association constant of PMX to HP-β-CD (Ka = 923.1 mol/L) was determined, while nuclear Overhauser (ROESY) analysis confirmed the formation of PMX/HP-β-CD inclusion complex, by detection of spatial proximities between hydrogens from PMX aromatic ring and cyclodextrin's cavity. In two in vitro toxicity models (mouse 3T3 fibroblasts in culture and red blood cells hemolysis) pramoxine toxicity was significantly reduced upon complexation into HP-β-CD. These results point out PMX/HP-β-CD as a promising pharmaceutical formulation to improve the bioavailability of pramoxine, allowing its application beyond topical anesthesia.

    Palavras-Chave: anesthesia; oligosaccharides; complexes; anesthetics; clathrates; nuclear magnetic resonance; stoichiometry; antimitotic drugs; hemolysis; chemical composition

    Icon

  • IPEN-DOC 27553

    MILAGRE, MARIANA X. ; FRANCO, MARGARETH ; GENEZINI, FREDERICO ; WIMPORY, ROBERT C.; YOKAICHIYA, FABIANO; COSTA, ISOLDA . A correlation between microstructure and residual stress in the 6061 Al–Mg–Si alloy with different thermomechanical process. SN Applied Sciences, v. 2, n. 12, 2020. DOI: 10.1007/s42452-020-03945-y

    Abstract: Depending on the nature of the loading during service, the level and nature of residual stress can contribute to the lower service-life of a component. In this study the internal level of the residual stress of a 6061 Al–Mg–Si alloy with different thermomechanical processes was evaluated by residual stress neutron diffraction (RSND). Commercial tempers such as T6 (peak aged) and O (annealed) were compared with the 6061 alloy after different steps of a thermomechanical processing used for the manufacturing of nuclear fuel plates, R3 and R9H60. The results showed that the lowest level of residual stress was found for the peak age, T6 condition. This was associated with the highest microhardness value (highest density of "β″ phase) and lowest grain size. The O temper was the only condition which showed compressive residual stress and the most coarsened precipitates. The nuclear thermomechanical processes, R3 and R9H60, resulted in increased level residual stress related to the T6 and showed a tensile nature in relation to its parent material (6061-O). Moreover, the RSND technique allows observing that the texture is also higher for the samples processed by the nuclear thermomechanical process due the hot rolling stage.

    Icon

  • IPEN-DOC 25785

    MARIANO, KELLI C.F.; NASCIMENTO, MONICA H.M. do; QUEROBINO, SAMYR M.; CAMPOS, ESTEFANIA V.R.; OLIVEIRA, JHONES L. de; YOKAICHIYA, FABIANO; FRANCO, MARGARETH K.K.D. ; ALBERTO-SILVA, CARLOS; PAULA, ENEIDA de; LOMBELLO, CHRISTIANE B.; LIMA, RENATA de; FRACETO, LEONARDO F.; ARAUJO, DANIELE R. de. Influence of chitosan-tripolyphosphate nanoparticles on thermosensitive polymeric hydrogels: structural organization, drug release mechanisms and cytotoxicity. International Journal of Polymeric Materials and Polymeric Biomaterials, v. 69, n. 9, p. 592-603, 2020. DOI: 10.1080/00914037.2019.1596909

    Abstract: Chitosan-tripolyphosphate (CS-TPP) nanoparticles containing naproxen (NPX) were dispersed in poloxamer (PL) as unique (PL407) or binary (PL407-PL403) systems. Nanoparticles presented diameter of 250nm and zeta potential of 35mV with drug loading and encapsulation efficiency of 98.4 ± 0.3% and 36.9 ± 0.12%, respectively. NPX-CS-TPP shifted the sol-gel transition and micellization temperatures. PL407-PL403 systems presented G0 >G00 compared to PL407. SAXS patterns revealed transitions from lamellar to hexagonal phase organizations with low drug release rates, in the presence of CS-TPP nanoparticles. NPX-CS-TPP-PL407 induced lower cytotoxicity compared to PL407-PL403 in fibroblasts and osteoblasts, making them promising systems for intra-articular delivery.

    Palavras-Chave: polysaccharides; chitin; nanoparticles; antipyretics; drugs; viability; animal cells; sensitivity; temperature dependence; hydrogels

    Icon

  • IPEN-DOC 27146

    OLIVEIRA, L.P. de; SOUZA, A.P.S.; YOKAICHIYA, F.; GENEZINI, F.A. ; FRANCO, M.K.K.D. . Monte Carlo simulations of the S-shaped neutron guide. Journal of Instrumentation, v. 15, n. 1, p. 1-14, 2020. DOI: 10.1088/1748-0221/15/01/P01012

    Abstract: Neutron transport along guides is governed by the Liouville theorem and the technology involved has advanced in recent decades. Computer simulations have proven to be useful tools in the design and conception of neutron guide systems in facilities. In this study, we use a Monte Carlo method to perform simulations for an S-shaped neutron guide with different dimensions for a Small-Angle Neutron Scattering (SANS) instrument, through the MCSTAS software. Awavelength cutoff is observed and shown to be dependent on the geometrical parameters of the guide. Results for the neutron flux at sample position are presented and greater sensitivity of cutoffs concerning the curvatures of the guides than to their lengths is noticed. Our results are in agreement with those obtained from the Acceptance Diagram method and we analyse the beam divergence behaviour along the S-shaped guide.

    Palavras-Chave: monte carlo method; neutron guides; neutron sources; simulation; computerized simulation; computer calculations; shape; neutron transport; small angle scattering; computer codes

    Icon

  • IPEN-DOC 27147

    SOUZA, A.P.S.; OLIVEIRA, L.P. de; YOKAICHIYA, F.; GENEZINI, F.A. ; FRANCO, M.K.K.D. . Neutron Guide Building instruments of the Brazilian Multipurpose Reactor (RMB) project. Journal of Instrumentation, v. 15, n. 4, p. 1-24, 2020. DOI: 10.1088/1748-0221/15/04/P04011

    Abstract: A growing community of scientists has been using neutrons in the most diverse areas of science. In order to meet the researchers demand in the areas of physics, chemistry, materials sciences, engineering, cultural heritage, biology and earth sciences, the Brazilian Multipurpose Reactor (RMB) will provide 3 thermal guides and 3 cold guides, with the installation of several instruments for materials characterization. In this study, we present a standard design requirement of two primordial instruments, namely Sabiá and Araponga. They are, respectively, cold and thermal neutron instruments and correspond to a Small-Angle Neutron Scattering (SANS) and High-Resolution Powder Neutron Diffractometer (HRPND) to be installed in the Neutron Guide Building (N02) of RMB. To provide adequate flux for both instruments, we propose here an initial investigation of the use of simple and split guides to transport neutron beams to two different instruments on the same guide. For this purpose, we use Monte Carlo simulations utilizing McStas software to check the efficiency of thermal neutron transport for different basic configuration and sources. By considering these results, it is possible to conclude that the split guide configuration is, in most cases, more efficient than cases that use transmitted neutron beams independently of source. We also verify that the employment of different coating indexes for concave and convex surfaces on curved guides is crucial, at least on simulated cases, to optimise neutron flux (intensity and divergence) and diminish facility installation cost.

    Palavras-Chave: neutron guides; neutron sources; neutron transport; rmb reactor; buildings; cold neutrons; thermal neutrons; reactor instrumentation; simulators; small angle scattering; neutron diffraction; scattering; monte carlo method

    Icon

  • IPEN-DOC 27558

    FRANCO, MARGARETH K.K.D. ; SEPULVEDA, ANDERSON F.; VIGATO, ARYANE A.; OSHIRO, ALISSON; MACHADO, IAN P.; KENT, BEN; CLEMENS, DANIEL; YOKAICHIYA, FABIANO; ARAUJO, DANIELE R. de. Supramolecular structure of temperature-dependent polymeric hydrogels modulated by drug incorporation. ChemistrySelect, v. 5, n. 42, p. 12853-12861, 2020. DOI: 10.1002/slct.202001116

    Abstract: Poloxamers or Pluronics® (PL) have been described as promising pharmaceutical and cosmetics matrices. Herein, we have explored the structural organization of hydrogel formulations composed of PL F‐127 and PL L‐81, considering their different hydrophilic‐lipophilic balances and interactions with an antimigraine drug, sumatriptan succinate (SMT). Hydrogels phase organizations were investigated by X‐ray diffraction (XRD) and Small Angle Neutron Scattering (SANS) to establish the relationship between structural features and drug release modulation. XRD analysis revealed very low intensity peaks for hydrogels containing SMT due to the presence of small amounts of SMT as crystalline form, which is an evidence of drug incorporation into hydrogels. At physiological temperature, a structural transition from lamellar to hexagonal was observed after SMT incorporation. In addition, SANS patterns displayed a distorted hexagonal structure, (calculated q2 >experimental q2), indicating the presence of a comprised structure compared to a perfect hexagonal assembly. This structural shift however have no influence on the drug release mechanism, allowing the SMT molecules to access the micellar and intermicellar hydrophilic spaces, with release mechanism dependent on the drug diffusion (R2=0.998 ≥ 0.986) from the hydrogel to the medium and release constant (Krel) values from 9.8 to 14.7 %.h−1; 31.5 to 39.1 %.h−1/2; 0.84 to 1.2 %.h−n for Zero‐order, Higuchi and Korsmeyer‐Peppas models, respectively. Using SMT as a drug model, it could be concluded that the drug access to the micellar/intermicellar hydrophilic spaces can be modulated by interplaying the polarity of binary PL‐based hydrogels. Therefore, drug release constants and mechanisms will be then dependent on the hydrogels physico‐chemical and structural properties, which determine the drug diffusion from the hydrogel to the release medium.

    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.