13 resultados para Organic group

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Acetylacetone has been used as a chemical modifier for the synthesis of undoped and Tb3+-doped Y3Al5O12 powders. A systematic investigation concerning its influence on the structural and morphological properties of amorphous and crystallized samples has been carried out. These properties have been comparatively studied by means of X-ray diffraction, infrared spectroscopy, SEM, XAS and SAXS. 27Al NMR and EPR experiments have been performed to complete the study. The combined results have evidenced that acetylacetone promotes organic groups departure during calcination, entailing a better structural organization at lower temperatures compared with unmodified powders. Structuration has been proven to occur at short-scale range until a 600°C heating treatment before being extended by coalescence at higher temperatures. Finally, the presence of acac ligands on the alkoxides leads to a monomer-cluster aggregation process, and thus to a more open network. © 2010 The Royal Society of Chemistry.

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The widespread use of poly(3-hexylthiophene) (P3HT) in the active layers of organic solar cells indicates that it possesses chemical stability and solubility suitable for such an application. However, it would be desirable to have a material that can maintain these properties but with a smaller bandgap, which would lead to more efficient energy harvesting of the solar spectrum. Fifteen P3HT derivatives were studied using the Density Functional Theory. The conclusion is that it is possible to obtain compounds with significantly smaller bandgaps and with solubility and stability similar to that of P3HT, mostly through the binding of oxygen atoms or conjugated organic groups to the thiophenic ring. © 2013 Wiley Periodicals, Inc.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The radial mycelial growth of Lentinula edodes (Berk) Pegler, strain LE-96/13, was studied in culture media prepared with organic residues extract, by using substrates prepared with pineapple (Ananas comosus (L.) Merril) crown, Astrocaryum aculeatum Meyer peel, Theobroma grandiflorum Schum shell, Musa sp. (genomic group AAB, subgroup Pacovan) peel, and Musa sp. (genomic group AAB, subgroup Praia) peel, with three supplementation levels with wheat bran (0, 10 and 20%), and incubated at 25 degrees C. The experimental design was totally randomized, in a 5x3 factorial scheme, adding up 15 treatments with 4 repetitions, and each repetition corresponding to a Petri dish. The diameter of the colony was evaluated daily during nine days of incubation. After that period, it was verified that the highest mycelial growth averages of strain LE-96/13 of L. edodes were found in culture media prepared with T. grandiflorum Schum shell (whose supplementation with wheat bran was favorable for Mushroom development) and A. aculeatum Meyer peel (whose supplementation did not favor the mycelial growth of L. edodes in relation to the medium not supplemented).

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Background Capsular contracture is the main complication related to breast silicone implants, and its prevention remains a medical challenge. The authors present experimental research examining the effect of external ultrasound on the formation and contracture of peri-implant capsules.Methods In this study, 42 male Wistar rats had a 2-mm smooth surface implant placed in a dorsal submuscular pocket. They then were separated into ultrasound'' and control'' groups that received repeated external applications either with or without the ultrasound power on. Ultrasound applications were given three times a week for a period of 90 days. After that, both groups were housed under the same conditions with no application scheduled. Five animals of each group, killed at 30, 60, 90, and 180 days, had their implants removed along with the capsule, which received a special histologic preparation via annular sectioning that provided wide circumferential observation of the capsular tissue. Sections were stained with hematoxylin/eosin stain, Masson's trichrome stain, and Pricrosirius Red stain for regular microscopic evaluation under normal and polarized light.Results Histologic data showed that capsules from the ultrasound and control groups had statistically significant differences. Ultrasound application developed a capsular architecture similar to that shown within textured silicone implants, and its effect had an early definition with subsequent stabilization.Conclusion The authors conclude that early and repeated external ultrasound application enhances the thickness, cellular count, and vascularity of smooth silicone capsular tissue, whereas it diminishes the pattern of parallel orientation of collagen fibers.

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Silica gel surface modified with imidazolylpropyl group was used to adsorb MX2 (M = Mn, Ni, Cu, Zn, and Cd; X = Cl, Br, and I) and FeCl3 from ethanol and acetone solution. The adsorption capacity and the intensity of the adsorption were determined by using the Langmuir equation. The influences of the solvent, temperature, and degree of functionalization on the adsorption were also studied. The infrared spectra of the functionalized silica were recorded between 1700-1300 cm-1. The bands of the imidazole skeletal vibrations are shifted to higher frequencies upon metal-to-base nitrogen interaction. © 1985.

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The effect of an organic acid mixture (OA) and a Lactobacillus-based probiotic culture on Salmonella enteritidis (SE) infection in broiler chicks was evaluated. In exp. 1, chicks were challenged by oral gavage with SE, held in chick boxes for 2 h and randomly assigned to either untreated control or continuous OA treatment in the drinking water. Crop and cecal tonsils were cultured at 48 h and 5 d post-challenge for recovery of SE. Recovery of SE in the crop and cecal tonsils at 48 h was significantly (p<0.05) lower in the OA treated group as compared to control chickens but not different at 5d. In exps.2 and 3, chicks were SE challenged, held in chick boxes for 2 h and randomly assigned to either untreated control, probiotic, OA, or probiotic+OA. After 24 or 48 h, crop and cecal tonsils were cultured for the presence or absence of SE. After 24 h, probiotic or probiotic+OA significantly reduced SE recovery from the crop as compared to controls. All treatments reduced SE recovery from the cecal tonsils at 24 h. While no significant differences were observed in SE recovery from crop at 48 h, SE recovery from probiotic and or probiotic+OA groups was significantly lower than the controls in the cecal tonsils. These data suggest that combination treatment with the selected OA and Lactobacillus-based probiotic culture is more effective than individual treatment for Salmonella reduction in chicks. © Asian Network for Scientific Information, 2007.