227 resultados para aerobic oxidation


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The present study was carried out to evaluate the effect of statins associated with physical exercise (PE) in liver cells in dyslipidemic rats through cariometry. The animals were divided into six groups: animals subjected to a hypercholesterolemic diet (HD), simvastatin, with (G1) and without (G2) physical exercise (PE); HD submitted (G3) or not (G4) to PE, and commercial food diet (F) with (G5) and without (G6) PE. Histological analysis of the liver was performed by staining the slides with hematoxylin and eosin. The cariometric study included measuring the major and minor diameters of the hepatocytes nuclei. The Shapiro-Wilk test was also performed. To determine the differences among the groups, the Kruskal-Wallis Test with Dunn's post-test were conducted. The significance level was set at 5%. No difference was found in the hepatocytes nuclei between G5 and G6. When these groups were related with G3 and G4, reduced nuclei were observed. There was no difference between G1 and G6. The comparison between G6 and G2 showed that the nuclei in G2 were smaller. No difference was detected between G5 and G1. Changes were observed in the nuclei shape in G2 in comparison to G1. Considering G2 and G3, a decrease in the size of nuclei was observed in G3. On the other hand, G2 showed changes in shape in the comparative analysis with G4. The size and shape of G1 nuclei were larger than G3 as well as changes in shape were observed when compared to G4. G4 showed smaller nuclei than G3. Therefore, F, associated or not with the practice of PE, does not alter the size and shape of the hepatocytes nuclei; HD combined with sedentarism influences changes in the morphometric parameters of hepatocytes; and the association of simvastatin and PE seems to protect the hepatocytes nuclei with regard to HD.

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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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(Photo)electrochemical experiments on pyrite electrodes in acetic acid-acetate buffer (pH = 4.5) are conducted to clarify the main oxidation reactions and the nature of the products. Electrochemical reactions in the -0.40 to 1.25 V (SHE) potential range are studied, and the production of iron (III) polysulfide from anodically formed iron oxides and polysulfides is discussed. Charges experimentally obtained are considered for the estimation of the most likely stoichiometry of the metallic polysulfide. The photoselectivity of the pyrite corrosion process indicates that the oxidation reactions of Fe2+ and S-2(2-) an not consecutive. The changes in stoichiometry and/or annihilation of crystalline structure defects are responsible for the observed photosensitivity of pyrite. A description of light effects on the interfacial behaviour and stability of pyrite is presented in terms of conduction and valence band energies, and thermodynamic potentials. (C) 2001 Elsevier Science B.V. All rights reserved.

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

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The electrocatalytic oxidation of 1-propanol was investigated on platinum electrodes modified by submonolayers of Pb and Sn in acid media. An increase of oxidation rates observed for both Pb and Sn, and the influence of theta values was investigated. The values of the apparent activation energy evaluated from the Arrhenius plots concerning the electrochemical oxidation of 1-propanol on modified platinzed platinum electrodes, reveal a significant decrease in the presence of upd Sn and Ph adatoms. A decrease from 56 to 26 U mol(-1) in the presence of Sn. and from 78 to 25 U mol(-1) for Ph adatoms are some illustrative values which reflect the promoting effect of the upd adatoms.

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

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This study aimed to evaluate the sensitiveness of the information obtained for the residual lignin from Eucalyptus grandis kraft pulps analyzed through the nitrobenzene oxidation, copper oxide (CuO) reduction and acidolysis techniques. The chips were cooked, resulting pulps of kappa number 14,5 and 16,9, respectively. Both lignins' pulps were evaluated through three methods (nitrobenzene oxidation, copper oxide oxidation and acidolysis). Then, they were subjected to an oxygen delignification stage. The 16,9 kappa number pulp resulted in higher levels of non-condensed lignin structures by the acidolysis method, higher syringyl/vanillin ratios (S/V) by the nitrobenzene and copper oxide methods and better performance in the oxygen delignification stage. The different methods allowed to differ the residual lignin pulps with kappa number 14,5 and 16,9, and the nitrobenzene oxidation method showed the highest sensitiveness in this study results.

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Aim. The aim of this pilot study was to compare strength performance and salivary cortisol levels response during a single strength session, and a strength session after 30 min of high-intensity aerobic exercise (concurrent condition).Methods. Saliva was collected from 7 male subjects, before and after all exercise bouts, and the maximum number of repetitions (MNR) and total volume (TV) in the different conditions assessed.Results. The MNR and TV were reduced in concurrent condition compared with control condition. Strength exercise in the concurrent condition induced higher salivary cortisol in relation to strength exercise or to and high-intensity aerobic exercise, separately.Conclusion. The different salivary cortisol profile in response to concurrent exercise reflects the faster reactivity of the hypothalamic-pituitary-adrenocortical system in this circumstance.

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The oxidation of ethanol (EtOH) at Pt(111) electrodes is dominated by the 4e path leading to acetic acid. The inclusion of surface defects such as those present on stepped surfaces leads to an increase of the reactivity towards the most desirable 12e path leading to CO2 as final product. This path is also favored when the methyl group is more oxidized, as in the case of ethylene glycol (EG) that spontaneously decomposes to CO on Pt(111) electrodes, thus showing a more effective breaking of the C-C bond. Some trends in reactivity can be envisaged when other derivative molecules are compared at well-ordered electrodes. This strategy was used in the past, but the improvement in the electrode pretreatment and the overall information available on the subject suggest that relevant information is still missing.