Flavonoids and isoflavonoids from Gynerium sagittatum

Four flavonoids namely (2R,3R)-2,3-trans-7,4 '-dimethoxydihydroflavonol, (2R,3S,4S)-2,3-trans-3,4-cis-7,4'-dimethoxy-3,4-flavandiol, 6-hydroxy-7,4 '-dimethoxyflavone, 6,7,4 '-trimethoxyflavone, along with the known isoflavonoids ferreirin, dihydrocajanin, dalbergioidin, dihydrobiochanin A and biochanin A and other I I known compounds were isolated from the roots of Gynerium sagittatum. The structural characterization of these compounds was carried out via one- and two-dimensional NMR experiments in combination with ESI-MS. Finally a quantitative analysis of the isoflavones of the methanolic extract was performed by LC-ESI-MS. The high quantity of isoflavonoids found in G. sagittatum makes this plant a good natural source of isoflavonoids. (c) 2007 Elsevier Ltd. All rights reserved.

Towards an insight on the photoluminescence of disordered CaWO4 from a joint experimental and theoretical analysis

A joint experimental and theoretical study has been carried out to rationalize for the first time the photoluminescence (PL) properties of disordered CaWO4 (CWO) thin films. From the experimental side, thin films of CWO have been synthesized following a soft chemical processing, their structure has been confirmed by X-ray diffraction data and corresponding PL properties have been measured using the 488 nm line of an argon ion laser. Although we observe PL at room temperature for the crystalline thin films, the structurally disordered samples present much more intense emission. From the theoretical side, first principles quantum mechanical calculations, based on density functional theory at B3LYP level, have been employed to study the electronic structure of a crystalline (CWO-c) and asymmetric (CWO-a) periodic model. Electronic properties are analyzed in the light of the experimental results and their relevance in relation to the PL behavior of CWO is discussed. The symmetry breaking process on going from CWO-c to CWO-a creates localized electronic levels above the valence band and a negative charge transfer process takes place from threefold, WO3, to fourfold, WO4,. tungsten coordinations. The correlation of both effects seems to be responsible for the PL of amorphous CWO. (c) 2005 Elsevier B.V. All rights reserved.

Estrategias de articulación de políticas sociales

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La crisis eléctrica en Chile: antecedentes para una evaluación de la institucionalidad regulatoria

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Cu0.5Zn0.5Fe2O4 ferrite for application as a soft magnetic material

This work involved the synthesis and characterization of Cu0.5Zn0.5Fe2O4 ferrite powders prepared by combustion reaction for use as soft magnetic materials. The powders were characterized by nitrogen adsorption (BET), XRD, Rietveld refinement, SEM, TEM and magnetic measures. The results indicate that the combustion reaction yielded crystalline powders containing spinel ferrite as the primary phase and traces of Fe2O3 as secondary phase. The crystallite size and lattice microdeformation calculated from Rietveld refinements were 36 and 0.24 nm, respectively. The micrographic analysis revealed particles smaller than 100 nm and fine particle agglomerates. The particles were approximately spherical and their size, calculated by TEM, was 29 nm. The magnetic parameters indicated that the Cu-Zn ferrite powders presented closed hysteresis loops and soft magnetic properties. © (2012) Trans Tech Publications, Switzerland.

Informe de la Reunión Regional Latinoamericana Preparatoria de la Conferencia Internacional sobre Población, realizada en el marco del Séptimo Período de Sesiones del Comité de Expertos Gubernamentales de Alto Nivel = Report of the Latin American Regional Preparatory Meeting for the International Conference on Population, held within the Seventh Session of the Committee of High-Level Government Experts

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Subcutaneous tissue reaction and cytotoxicity of polyvinylidene fluoride and polyvinylidene fluoride-trifluoroethylene blends associated with natural polymers

Cytotoxicity and subcutaneous tissue reaction of innovative blends composed by polyvinylidene fluoride and polyvinylidene fluoride-trifluoroethylene associated with natural polymers (natural rubber and native starch) forming membranes were evaluated, aiming its applications associated with bone regeneration. Cytotoxicity was evaluated in mouse fibroblasts culture cells (NIH3T3) using trypan blue staining. Tissue response was in vivo evaluated by subcutaneous implantation of materials in rats, taking into account the presence of necrosis and connective tissue capsule around implanted materials after 7, 14, 21, 28, 35, 60, and 100 days of surgery. The pattern of inflammation was evaluated by histomorphometry of the inflammatory cells. Chemical and morphological changes of implanted materials after 60 and 100 days were evaluated by Fourier transform infrared (FTIR) absorption spectroscopy and scanning electron microscopy (SEM) images. Cytotoxicity tests indicated a good tolerance of the cells to the biomaterial. The in vivo tissue response of all studied materials showed normal inflammatory pattern, characterized by a reduction of polymorphonuclear leukocytes and an increase in mononuclear leukocytes over the time (p < 0.05 Kruskal-Wallis). On day 60, microscopic analysis showed regression of the chronic inflammatory process around all materials. FTIR showed no changes in chemical composition of materials due to implantation, whereas SEM demonstrated the delivery of starch in the medium. Therefore, the results of the tests performed in vitro and in vivo show that the innovative blends can further be used as biomaterials. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 101B: 1284-1293, 2013. Copyright © 2013 Wiley Periodicals, Inc.

Estudo das formas aumentativas e diminutivas em português arcaico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo das sibilantes nas cantigas de Santa Maria

Pós-graduação em Linguística e Língua Portuguesa - FCLAR

Estudo das formas verbais do pretérito perfeito do modo indicativo nas Cantigas de Santa Maria

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Rumores da escrita, vestígios do passado: uma interpretação fonológica das vogais do português arcaico por meio da poesia medieval

A proposta do presente livro é oferecer ao leitor uma descrição fonológica das qualidades vocálicas vigentes na primeira fase (período trovadoresco) do português arcaico a partir da análise das rimas e da grafia das Cantigas de Santa Maria, de Afonso X, o Sábio, Rei de Leão e Castela, elaboradas na segunda metade do século XIII.

Um estudo das consoantes róticas nas Cantigas de Santa Maria

Este trabalho de monografia visa iniciar uma discussão acerca de aspectos fonológicos relativos às consoantes róticas no Português Arcaico, a partir da análise de um recorte das Cantigas de Santa Maria, de Afonso X (1121-1284). Foi realizado um levantamento da forma gráfica das palavras para a posterior quantificação das ocorrências de róticas nessas palavras. Depois de analisada a literatura básica relativa ao PA, foram feitas considerações sobre o corpus deste trabalho, no que diz respeito às afirmações feitas pelos autores estudados. A partir dos resultados desse estudo, constatamos a semelhança existente entre os sistemas consonantais do Português Arcaico e do Português Brasileiro, principalmente no que diz respeito: a) aos processos de neutralização de róticas em contexto de coda e b) aos grafemas e , que já não representavam em PA sons de caráter distintivo no contexto de travamento silábico, como ocorre em PB

Sândi vocálico externo no Poruguês Arcaico

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Uma análise das consoantes róticas nas cantigas de Santa Maria

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)