55 resultados para DIHYDRODIOL ISOMERS


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The consumption of carotenoid-rich vegetables such as tomatoes and tomato sauces is associated with reduced risk of several chronic diseases. The predominant carotenoids in tomato products are in the (all-E) configuration, but (Z) isomers can be formed during thermal processing. The effect of cooking time (15, 30, 45 and 60 min) and the addition of extra virgin olive oil (5% and 10%) on the carotenoid extractability of tomato sauces was monitored using liquid chromatography-tandem mass spectrometry (LC-ESI-MS/MS) and LC-ultraviolet detection (LC-UV). The thermal treatment and the addition of extra virgin olive oil increased the levels of antioxidant activity, total carotenoids, Z-lycopene isomers, -carotene and -carotene. These results are of particular nutritional benefit since higher lycopene intake has been associated with a reduced risk of lethal prostate and a reduction of prostate-specific antigen (PSA) levels. Moreover, -carotene has been reported to suppress the up-regulation of heme oxygenase-1 gene expression in a dose dependent manner and to suppress UVA-induced HO-1 gene expression in cultured FEK4.

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The cct isomers [RuCl 2(CO) 2(PPh 3) 2] (1) and [RuCl 2(CO) 2(AsPh 3) 2] (2) were synthesized from [RuCl 3(PPh 3) 2DMA]DMA and [RuCl 3(AsPh 3) 2DMA]DMA, respectively. The complexes were characterized by elemental analysis, IR and UV-vis spectroscopy and their molecular structures were found to be cis-cis-trans isomers by X-ray crystallography. Cyclic voltammetry data show that the tripenylphosphine stabilizes better the ruthernium(II) complex than the tripenylarsine ligand. © 1994.

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The Sol-gel process has facilitated the processing of Organic-Inorganic Hybrid Materials with several scientific applications and technologies. The hybrid combine the advantages of the Sol-gel process with specific characteristics of organic polymers, allowing processing of thin films without fractures or fissures. The incorporation of azo dyes in polymer matrices has been widely used in the investigation of optical properties. The azo dye Disperse Red (DR1) presents optical alterations when exposed to visible or ultraviolet light. The alterations occur due to transitions of their isomers, trans and cis, caused by photoisomerization, due to electronic transitions of azo group (-N=N-), presenting photochromic and/or photorefractive effects. The hybrid system used in this work is the precursor 3- Glycidoxypropyl-Trimethoxi-silane (GPTS), the Tetraethylorthosilicate (TEOS) and DR1 as a dopant. The characterizations were performed using absorption spectroscopy UV-Vis which allowed the identification of the absorption bands and its variations when the samples were treated thermally and/or illuminated by ultraviolet light

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Persistent Organic Pollutants (POPs) are chemical substances extraordinarily toxic and persistent in the environment. Due to these properties, POPs are targets of the Stockholm Convention which aims to provide means to eliminate production and use by encouraging the reduction and, where possible, eliminating the release of these contaminants to the environment. One of the articles of this _Convention aims to assess the basal levels of such substances in the environment to monitor both the reduction of release to the environment, and to assess human exposure, using analyzes of milk and air for example. Although efforts to control POPs production and release to the environment have been made, data about their levels in Brazil are still scarce, mainly in the atmosphere or indoor environment. Considering the permanence of people inside its house, this study presents a method for POP extraction from XAD-2 sorbent employed in indoor air sampling, with identification and quantification by GC-ECD. GC-ECD linear range of the studied analytes, congeners of polychlorinated biphenyls (PCB) (28, 52, 101, 118, 138, 153 and 180), DDTs and their metabolites (DDDs, DDEs) and endosullan (isomers c - and 13 - and metabolite endosulfan sulfate) ranged between 0.5 and 16.0 ng mL-I with r2 > 0.967. The method developing consist of selecting the extraction solvent system by agitation (90 rpm, 1 hour) with n-hexan,e (2 mL) or n-hexane:acetone (1:1, v/v) (2 mL), concentration the extract with a gentle N2 stream, and evaluation of breakthrough with passage or air through the fortified XAD-2 cartridge before extraction, employing a low volume air suction pump (Pump Model 224 universal-PCXR8; 5-5000 mL min-1, SKC Inc., Eighty Four, PA, USA), Calibrator Dry-Cal DC-Lite (BIOS, Butler, NJ, USA)). Two fortification levels were employed, 15 and 30 ng. After selecting n-hexane as extraction solvent, with accuracy and precision ranging...

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)