999 resultados para Siglos IX-X


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Different secondary caries models may present different results. The purpose of this study was to compare different in vitro secondary caries models, evaluating the obtained results by polarized-light microscopy (PLM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Standardized human enamel specimens (n = 12) restored with different materials (Z250 conventional composite resin-CRZ, Freedom polyacid-modified composite resin-CRF, Vitremer resin-modified glass-ionomer-GIV, and Fuji IX conventional glass-ionomer cement-GIF) were submitted to microbiological (MM) or chemical caries models (CM). The control group was not submitted to any caries model. For MM, specimens were immersed firstly in sucrose broth inoculated with Streptococcus mutans ATCC 35688, incubated at 37 degrees C/5% CO(2) for 14 days and then in remineralizing solution for 14 days. For CM, specimens were submitted to chemical pH-cycling. Specimens were ground, submitted to PLM and then were dehydrated, gold-sputtered and submitted to SEM and EDS. Results were statistically analyzed by Kruskall-Wallis and Student-Newman-Keuls tests (alpha = 0.05). No differences between in vitro caries models were found. Morphological differences in enamel demineralization were found between composite resin and polyacid-modified composite resin (CRZ and CRF) and between the resin-modified glass-ionomer and the glass-ionomer cement (GIF and GIV). GIF showed higher calcium concentration and less demineralization, differing from the other materials. In conclusion, the glass-ionomer cement showed less caries formation under both in vitro caries models evaluated. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 90B: 635-640, 2009

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Secondary caries is the main cause of direct restoration replacement. The purpose of this study was to analyze enamel adjacent to different restorative materials after in situ cariogenic challenge using polarized-light microscopy (PLM), scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDS). Twelve volunteers, with a low level of dental plaque, a low level of mutans streptococci, and normal salivary flow, wore removable palatal acrylic appliances containing enamel specimens restored with Z250 composite, Freedom composite, Fuji IX glass-ionomer cement, or Vitremer resin-modified glass-ionomer for 14 days. Volunteers dripped one drop of 20% sucrose solution (n = 10) or distilled water (control group) onto each specimen 8 times per day. Specimens were removed from the appliances and submitted to PLM for examination of the lesion area (in mm(2)), followed by dehydration, gold-sputtering, and submission to SEM and EDS. The calcium (Ca) and phosphorus (P) contents were evaluated in weight per cent (%wt). Differences were found between Z250 and Vitremer, and between Z250 and FujiIX, when analyzed using PLM. Energy-dispersive X-ray analysis results showed differences between the studied materials regarding Ca %wt. In conclusion, enamel adjacent to glass-ionomer cement presented a higher Ca %wt, but this material did not completely prevent enamel secondary caries under in situ cariogenic challenge.

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Incluye Bibliografía

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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El objetivo de la presente investigación, el catálogo y estudio de las gramáticas de italiano destinadas a hispanohablantes de los siglos XVIII y XIX, se encuadra en el macrosector gramaticográfico de la historiografía lingüística, en el cual el estudio de las gramáticas de las lenguas dirigidas a hablantes nativos y a hablantes extranjeros, con los consiguientes cruces y trasvases de tradiciones gramaticales, es de significativo interés como destacan: (i) las tesis doctorales defendidas en los últimos quince años; (ii) los proyectos de investigación dirigidos y coordinados por prestigiosos estudiosos del sector; (iii) los congresos organizados para destacar y compartir las principales actualizaciones en torno a los estudios gramaticográficos; y (iv) las publicaciones que surgen de los tres puntos anteriores. El estudio presenta dos partes centrales: la primera (constituida por los capítulos 2 y 3) es la de catálogo y estudio de las diecinueve gramáticas que conforman el corpus en base a ocho áreas descriptivas (1. información catalográfica, 2. autor, 3. editor, 4. hiperestructura, 5. elementos peritextuales, gramaticales y didácticos, 6. variedad de textos y su secuencia didáctica, 7. caracterización, fuentes e influencias, y 8. localización); la segunda (capítulo 4) es la de estudio gramaticográfico de conjunto de los datos más relevantes de las areas de estudio utilizadas en las dos primeras partes. De este modo, daremos un panorama de conjunto sobre (i) la cronología de las obras y sus ediciones y rempresiones; (ii) la nacionalidad, profesión, condición religiosa, etc. de autores; (iii) la geografía de ediciones y editores; (iv) la descripción hiperestructural de las obras; (v) la estructura de los elementos peritextuales; (vi) las partes gramaticales y elementos que las componen; (vii) el verbo: definiciones y paradigma verbal; (vii) los elementos didácticos; (viii) las líneas de descripción gramatical; (ix) la localización de las gramáticas en las bibliotecas españolas.

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Trägerband: Ms. Praed. 97; Inc. oct. 29 Bd. 1 und 2; Inc. oct. 134; Vorbesitzer: Dominikanerkloster Frankfurt am Main

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Trägerband: Inc. gr. fol. 3 Bd. 3; Vorbesitzer: Dominikanerkloster Frankfurt am Main

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Trägerband: Inc. gr. fol. 3 Bd. 3; Vorbesitzer: Dominikanerkloster Frankfurt am Main