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Sandra Rocha Rumen Krastev Andreas F Thünemann M Carmo Pereira Helmuth M?hwald Gerald Brezesinski 《Chemphyschem》2005,6(12):2527-2534
The adsorption of amyloid beta-peptide at hydrophilic and hydrophobic modified silicon-liquid interfaces was characterized by neutron reflectometry. Distinct polymeric films were used to obtain noncharged (Formvar), negatively (sodium poly(styrene sulfonate)) and positively charged (poly(allylamine hydrochloride)) hydrophilic as well as hydrophobic surfaces (polystyrene and a polysiloxane-dodecanoic acid complex). Amyloid beta-peptide was found to adsorb at positively charged hydrophilic and hydrophobic surfaces, whereas no adsorbed layer was detected on hydrophilic noncharged and negatively charged films. The peptide adsorbed at the positively charged film as patches, which were dispersed on the surface, whereas a uniform layer was observed at hydrophobic surfaces. The thickness of the adsorbed peptide layer was estimated to be approximately 20 A. The peptide formed a tightly packed layer, which did not contain water. These studies provide information about the affinity of the amyloid beta-peptide to different substrates in aqueous solution and suggest that the amyloid fibril formation may be driven by interactions with surfaces. 相似文献
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Nanoengineering of iron oxide and iron oxide/silica hollow spheres by sequential layering combined with a sol-gel process 总被引:2,自引:0,他引:2
Fe2O3 and Fe2O3/SiO2 hollow spheres with tailored dimensions and compositions were created by consecutively coating polystyrene (PS) latices either with Fe3+ alternately adsorbed with Nafion or combining a sol-gel process based on the hydrolysis of tetraethoxysilane (TEOS), and subsequently removing the cores upon pyrolysis. 相似文献
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Vladislav V. Kravchenko Helmuth R. Malonek Gustavo Santana 《Mathematical Methods in the Applied Sciences》1996,19(17):1415-1431
The Dirac equation with a vector potential is considered using a biquaternionic formalism and boundary integral representations for its solutions are obtained. In order to characterize these solutions by a property of local approximability by linearization the corresponding notion of biquaternionic differentiability and its generalization in the sense of Bers (adapted to the spatial case) are given. 相似文献
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The influence of the restricted volume of poly(styrene sulfonate)/poly(allylamine hydrochloride) capsules of different size (2.2, 4.2, and 8.1 microm) on the TiO2-assisted photosynthesis of urea from inorganic precursors (CO2 and NO(3-)) in aqueous solution was demonstrated. Poly(vinyl alcohol) was employed as electron donor to facilitate the photosynthetic process. Decreasing the size of the confined microvolume of polyelectrolyte capsules accelerates the NO(3-) photoreduction, which is a limiting stage of the urea photosynthesis and, correspondingly, increases the efficiency of urea production. The highest yield of urea photosynthesis (37%) was achieved for Cu-modified TiO2 nanoparticles encapsulated inside 2.2 microm poly(styrene sulfonate)/poly(allylamine hydrochloride) capsules. 相似文献