936 resultados para CIS-TRANS PHOTOISOMERIZATION
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The sol-gel process and the wide variety of alkoxides commercially available have facilitated the processing of various Organic-Inorganic Hybrid Materials. In general, the hybrids are excellents matrix to incorporate organic or inorganic dopants that presents photochromic, thermochromic, and halochromic effects and in some cases photorefractive effects. The GPTS-TEOS hybrid matrix when deposited in the form of film is very resistant, adherent, has excellent transparency in visible region and allows to be doped with various azo-dye and metal salts of unusual oxidation states. One of the main characteristics of the azo-dyes when immersed in some hybrid matrix , is the capacity to isomerizes through group Azo (-N = N-) would can be commutated between the Cis (Z) and Trans (E) configurations by means of light or heat. Our goal was through the sol-gel process to prepare hybrid films of GPTS-TEOS doped with azo-dyes Methyl Red and Disperse Red 1, and characterize them optically. The characterizations are performed using techniques of UV / Vis spectroscopy, to identify changes in the absorption band of azo-dyes in the presence of optical pumping, (photochromic effects), in function of temperature (thermochromic effect). These properties are of wide scientific and technological interest because they will contribute to the confection Smart Windows (windows sensible to light), temperature sensors monitored optically and also in the recording of amplitude and phase diffraction gratings
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Triacrylate resins are widely used to fabricate 3D microstructures, photonic crystals and optical devices. These resins can be doped with photosensitive materials like Disperse Red 1 (DR1), an Azo dye that changes its molecular configuration from trans to cis (photoisomerisation) with variations in their optical absorption spectrum when irradiated with ultraviolet or visible light. The reversibility of this process is thermally activated and occurs when the molecule remains at dark. In this work was prepared a 1:1 mixture of ethoxylated-6-trimethylolpropane (SR499) and tris-2-hydroxyethyl-isocyanurate (SR368) triacrylate resins, plus photoinitiator Lucirin TPOL, forming a UV curable polymeric matrix doped with DR1. Thin films were deposited onto glass slides by spin-coating technique. The films showed photochromic effect when illuminated with a low power diode laser (450 nm and 50mW/cm2). This effect is reversible after sample is left in dark. Thermochromic effect was evaluated by optical absorption measurements in the range of 40 to 140oC, heating the samples in-situ
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Química - IQ
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Genética e Melhoramento Animal - FCAV
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The objective of this study was to evaluate the fatty acid profile and qualitative characteristics of meat from feedlot young bulls fed ground soybean or ground cottonseed, with or without supplementation of vitamin E. A total of 40 Red Norte young bulls, with an initial average age of 20 months, and an initial average BW of 339 +/- 15 kg, were allotted in a completely randomized design using a 2 x 2 factorial arrangement, with two oilseeds, and daily supplementation or not of 2500 IU of vitamin E. The experimental period was for 84 days, which was preceded by an adaptation period of 28 days. The treatments were ground soybean (SB), ground soybean plus vitamin E (SBE), ground cottonseed (CS) and ground cottonseed plus vitamin E (CSE). The percentage of cottonseed and soybean in the diets (dry matter basis) was 24% and 20%, respectively. Diets were isonitrogenous (13% CP) and presented similar amount of ether extract (6.5%). The animals were slaughtered at average live weight of 464 +/- 15 kg, and samples were taken from the longissimus dorsi muscle for the measurement of fatty acid concentration and the evaluation of lipid oxidation and color of the beef. Before fatty acid extraction, muscle tissue and subcutaneous fat of the longissimus dorsi were separated to analyze fatty acid profile in both tissues. Supplementation of vitamin E did not affect fatty acid concentration, lipid oxidation and color (P > 0.05). Subcutaneous fat from animals fed CS diet had greater C12: 0, C16: 0 and C18: 0 contents (P < 0.03). In addition, CS diets reduced the C18: 1 and C18: 2 cis-9, trans-11 contents in subcutaneous fat (P < 0.05). The muscle from animals fed CS tended to higher C16: 0 and C18: 0 contents (P < 0.11), and decreased C18: 1, C18: 2 cis-9, trans-11 and C18: 3 contents (P < 0.05) compared with SB. The Delta(9)-desaturase index was greater in muscle from animals fed SB (P < 0.01). At 42 days of age, meat from cattle fed SB had a greater lipid oxidation rate (P < 0.05). Meat from animals fed SB diets had less lightness and redness indices than meat from animals fed CS diets after 14 days of age. In conclusion, the addition of ground cottonseed in the finishing diets did increase the saturated fatty acid content of the longissimus dorsi. However, animals fed cottonseed exhibited greater lightness and redness of beef. In this study, the addition of vitamin E did not affect qualitative characteristics of meat.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)