Siloxane
Mostrando 25-34 de 34 artigos, teses e dissertações.
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25. Preparation and characterization of stationary phases of copolymer of dimethyl-methyl-phenyl siloxane on the silica for high porformance liquid / Preparação e caracterização de fases estacionarias de dimetil-metil-fenil siloxano sobre silica para cromatografia liquida de alta eficiencia
Em cromatografia líquida de alta eficiência (CLAE), a coluna é freqüentemente considerada como o "coração do sistema cromatográfico", pois é nela que ocorre a separação. Dessa forma, a busca por fases estacionárias capazes de realizar separações com alta eficiência e desempenho tem sido uma constante em muitos laboratórios de pesquisa. Polissi
Publicado em: 2005
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26. Synchrotron SAXS Studies of Nanostructured Materials and Colloidal Solutions: A Review
Structural characterisations using the SAXS technique in a number of nanoheterogeneous materials and liquid solutions are reviewed. The studied systems are protein (lysozyme)/water solutions, colloidal ZnO particles/water sols, nanoporous NiO-based xerogels, hybrid organic-inorganic siloxane-PEG and PPG nanocomposites and PbTe semiconductor nanocrystals embe
Materials Research. Publicado em: 2002-03
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27. New nuclear magnetic resonance methods for studying slow dynamics in organic solids: applications to polymers and proteins / Novas metodologias de ressonância magnética nuclear para o estudo da dinâmica lenta em materiais orgânicos no estado sólido: aplicações em polímeros e proteínas
Solid-State Exchange NMR is an important method to characterize details of dynamic process in materials science. However, the application of these techniques to study complex materials has been limited. In this work new solid-state Exchange NMR techniques, which allows efficient analysis of molecular motions in the millisecond time scale, are presented. The
Publicado em: 2001
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28. Avaliação da adaptação à dentina de vários agentes de proteção com ou sem sistemarestaurador adesivo, em função de diferentes tratamentos da superfície dentinária. / Evaluation of the marginal finishing of cavity preparations in relation to different instrumentation methods.
The present study evaluated the length and width of interface gaps between dentin and the following lining materials: chemically cured Dycal Advanced Formula II and light cured Prisma VLC Dycal and Ultra-Blend® plus calcium hydroxide bases; chemically cured Ketac Bond and light cured Vitrebond glass ionomer cements. Dentin cavities prepared in human teeth w
Publicado em: 2000
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29. Polissilanos e polissilanos ramificados
The polysilynes (SiPh)m, the linear polysilane (SiPhMe)n and the branched polysilanes [(SiPh)m(SiPhMe)n], [(SiPh)m(SiMe2)n], [(SiEt)m(SiPh2)n] and [(Sic-hex)m(SiPh2)n], with m/n ranging from 0,50/0,50 to 1,0/0,0, were synthesized in good yields from the sodium/toluene reductive coupling of the appropriate organochlorosilanes. The materiais were characterized
Publicado em: 1998
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30. Dinamica e reatividade de superficie de poli (dimetilsiloxano)s
Crosslinked polydimethylsiloxane (PDMS) heated at temperatures between 200 and 280°C for short periods (one-half to two hours), reveals a partially thermoplastic behavior. Earlier studies on silicone describe the phenomena occurring under heating as due to chemical reactions leading to the formation of oligomers and oxidation products, which cause degradati
Publicado em: 1994
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31. Silicatein α: Cathepsin L-like protein in sponge biosilica
Earth’s biota produces vast quantities of polymerized silica at ambient temperatures and pressures by mechanisms that are not understood. Silica spicules constitute 75% of the dry weight of the sponge Tethya aurantia, making this organism uniquely tractable for analyses of the proteins intimately associated with the biosilica. Each spicule contains a centr
The National Academy of Sciences.
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32. Cell growth on liquid interfaces: Role of surface active compounds
Anchorage-dependent fibroblasts can be cultured by using as a substrate the protein layer that spontaneously forms at the liquid-liquid interface between fluorocarbon fluids and tissue culture medium. For this novel substrate to be effective in supporting confluent cell layers, the protein monolayer must support the stresses exerted by spreading fibroblasts.
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33. Silicatein filaments and subunits from a marine sponge direct the polymerization of silica and silicones in vitro
Nanoscale control of the polymerization of silicon and oxygen determines the structures and properties of a wide range of siloxane-based materials, including glasses, ceramics, mesoporous molecular sieves and catalysts, elastomers, resins, insulators, optical coatings, and photoluminescent polymers. In contrast to anthropogenic and geological syntheses of th
The National Academy of Sciences.
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34. Identification of genes affecting production of the adhesive holdfast of a marine caulobacter.
Caulobacters are stalked bacteria that produce a structure termed a holdfast which enables firm attachment to surfaces. Tn5 insertion mutagenesis was used to identify genes affecting holdfast production or function in the marine strain MCS6. Twelve thousand Tn5 insertion mutants were screened for adhesion defects by an assay involving the attachment of cells