894 resultados para Oxidação electroquímica
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Pós-graduação em Ciência e Tecnologia de Materiais - FC
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Geografia - IGCE
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Nanotubes have been subject of studies with regard to their ability to promote differentiation of several cells lines. Nanotubes have been used to increase the roughness of the implant surfaces and to improve bone tissue integration on dental implant. In this study TiO2 nanotube layer prepared by anodic oxidation was evaluated. Nanotube formation was carried out using Glycerol-H2O DI(50-50 v/v)+NH4F(0,5 a 1,5% and 10-30V) for 1-3 hours at 37ºC. After nanostructure formation the topography of surface was observed using field-emission-scanning-microscope (FE-SEM). Contact angle was evaluated on the anodized and non-anodized surfaces using a water contact angle goniometer in sessile drop mode with 5 μL drops. In the case of nanotube formation and no treatment surface were presented 39,1° and 75,9°, respectively. The contact angle describing the wettability of the surface is enhanced, more hydrophilic, on the nanotube surfaces, which can be advantageous for enhancing protein adsorption and cell adhesion.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The aim of this study is to evaluate the effi ciency of oregano, sage, moringa and rosemary as natural antioxidants and propyl gallate as artifi cial antioxidant used in “stuffed food” made with CMS of tilapia (minced fi sh) and stored frozen for 120 days. Protein, fat, moisture and ashes determination, microbiological analysis and sensory evaluations were conducted in the beginning and the end of storage period. TBARS, BNVT, pH and psychrotrophic microorganism count were determined periodically. The antioxidants interfered in pH (6.17 and 6.55) and TBARS values during 120 days under freezing (-18o C). The lowest TBA values were found for oregano (0.158 mg de MDA. kg-1) and sage (0.186 mg de MDA.kg-1). The stuffed food made with CMS of tilapia, without antioxidant, had the most oxidation, and sage and moringa were not good source of antioxidant. BNVT values (11.41 – 12.35 mgN.100g-1) were not altered. The lowest pH value was found for the product with sage (6.20), but similar to the moringa and propyl gallate, while oregano and rosemary showed the highest values (6.63 and 6.29), at 5 days of storage. Microbiological analyses were in accordance with Brazilian legislation. Sensory evaluation indicated that the panelists preferred the formulations made with oregano and propyl gallate. The results showed that it is feasible to elaborate stuffed food made with CMS of tilapia as an alternative for the fi shery´s consumption, and sage was the most effi cient natural antioxidant among those tested in this study.
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The aim of this study was to determine the antioxidant activity of Moringa (Moringa oleifera Lam.) leaves flour in beef burger during storage for 120 days. Six hamburger formulations were processed: one control (without the use of additives), four with addition of Moringa leaves flour (0.10, 0.15, 0.20, and 0.25 g/100 g aggregate), and one with addition of synthetic antioxidant Propyl Gallate (0.01 g/100 g aggregate). The products were analyzed for their chemical composition with determinations of moisture, protein, dietary fiber, lipids, ash, carbohydrate, and caloric value after preparation. Microbiological and acceptance testing were performed at the beginning and after 120 days of storage. Determination of pH, instrumental color and lipid oxidation (TBARS) were performed at 1, 30, 60, 90 and 120 days of storage. All samples showed physical-chemical and microbiological tests in accordance with the Brazilian legislation. pH measurements were between 5.48 and 5.90; however, the intensity of red has changed according to the treatments and storage periods. The addition of Moringa leaves flour had no antioxidant effect on burgers, but its inclusion not only contributed to the improvement of nutritional quality, but also did not harm product acceptance.
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Vitamin C is vulnerable to oxidative degradation and then the aim of this study was conducting a literature review about quality control of vitamin C in finished products. The conclusion is determined multiple emulsions and products which contain encapsulant materials are able to protect it from oxidation ensuring its efficacy.
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É descrita a invenção de um método de modificação da superfície 5 de ligas de titânio empregando a oxidação anódica em ligas de Ti- 30Ta e Ti-7,5Mo para a obtenção de nanotubos perpendiculares ao substrato com diâmetro de 80-120 nm e comprimento de 100 nm-500 nm.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Caracterização física e química da carne de peito de aves de diferentes idades submetida à maturação
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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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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Currently has few studies today concerning the behavior of the ethyl alcohol hydrated combustible in the geological environment, results of eventual spill or leaks in a wide transport chain and distribution. This work discusses the results of an experiment in laboratorial scale, that involves the monitoring of alterations in physical properties a simulate leak of alcohol in a tank with sand saturated in water, during 4920 hours. Are applied electrical resistivity, induced polarization and spontaneous potential geophysical methods. The electric resistivity is clearly correlating to the ethanol degradation pattern. The chargeability demonstrated sensibility to this pattern, while the natural electric potential revealed direct association with the oscillations of groundwater level. The variability of the physical parameters monitoring probable control for ethanol degradation process in environment study.