Estudo das reações de oxidação de etileno glicol e glicerol sobre nanopartículas intermetálicas de PtSb/C e PdSb/C

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Long-Lasting Oscillations in the Electro-Oxidation of Formic Acid on PtSn Intermetallic Surfaces

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Chemical composition and lipoxygenase activity in soybeans (Glycine max L. Merr.) submitted to gamma irradiation

Soybeans are an important food due to their functional and nutritional characteristics. However, consumption by western populations is limited by the astringent taste of soybeans and their derivatives which results from the action of lipoxygenase, an enzyme activated during product processing. The aim of this study was to evaluate the effect of gamma irradiation on the chemical composition and specific activity of lipoxygenase in different soybean cultivars. Soybeans were stored in plastic bags and irradiated with doses of 2.5, 5 and 10 kGy. The chemical composition (moisture, protein, lipids, ashes, crude fiber, and carbohydrates) and lipoxygenase specific activity were determined for each sample. Gamma irradiation induced a small increase of protein and lipid content in some soybean cultivars, which did not exceed the highest content of 5% and 26%, respectively, when compared to control. Lipoxygenase specific activity decreased in the three cultivars with increasing gamma irradiation dose. In conclusion, the gamma irradiation doses used are suitable to inactivate part of lipoxygenase while not causing expressive changes in the chemical composition of the cultivars studied. (C) 2014 Elsevier Ltd. All rights reserved.

Electrical behavior of Bi0.95Nd0.05FeO3 thin films grown by the soft chemical method

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Bacterial and chemical leaching of chalcopyrite concentrates as affected by the redox potential and ferric/ferrous iron ratio at 22 degrees C

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A study of the main oxidation products of natural pyrite by voltammetric and photoelectrochemical responses

(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.

Electrochemical study of arsenopyrite weathering

Cyclic voltammograms and capacitance measurements are presented to characterize the mineral response at relatively moderate environmental conditions, pH 4.5 and T = 25degreesC. The experiments involve examining the rates of oxidation and the surface morphology of arsenopyrite, which is oxidized abiotically. The semiconducting properties of the mineral have been investigated in attempt to gain additional information of FeAsS dissolution behavior in acidic solutions at potentials close to the open circuit potential of the mineral. A mechanistic pathway for the anodic dissolution of arsenopyrite in open circuit conditions is also suggested. At high overpotentials, anodic reactions produce mainly sulfate and arsenate ions and may be described as hole limited. The reduction of orpiment-like compounds at potentials more negative than the open circuit potential is discussed.

Electrocatalytic effect of Pb and Sn adatoms on the oxidation of 1-propanol on platinized platinum electrodes: Determination of the apparent activation energy

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.

Apocinina versus diapocinina como inibidor da produção de peróxido de hidrogênio e ácido hipocloroso por neutrófilos ativados

Apocynin has been used as an efficient inhibitor of the multi-enzymatic complex NADPH oxidase in many experimental models involving phagocytic and nonphagocytic cells. The mechanism of inhibition has been linked with the previous activation of apocynin through the action of cellular peroxidases leading to the formation of a dimeric oxidation product, diapocynin. In this study we compared apocynin with pure diapocynin regarding their effects as scavenger of hydrogen peroxide and hypochlorous generated by glucose/glucose oxidase and myeloperoxidase respectively, and as inhibitors of the production of hydrogen peroxide and hypochlorous acid by activated neutrophils. The production of hydrogen peroxide was measured by the oxidation of the fluorescent substance Amplex Red and the production of hypochlorous acid by was measured as taurine-chloramine derivative using the chromogenic substrate 3,3’,5,5’- tetramethylbenzidine (TMB). Neutrophils (1 x106 cells/mL) were pre-incubated in PBS buffer supplemented with 1 mM calcium chloride, 0.5 mM magnesium chloride, 1 mg/mL glucose and 5 mM taurine in the presence or absence of inhibitors. The reactions were triggered by adding the soluble stimulus Forbol Miristate Acetate PMA or zymosan and incubated by additional 30 minutes. We found that pure diapocynin was not better than apocynin regarding its scavenger and inhibitory properties. These results suggest that the formation of diapocynin is not essential for the action of apocynin as inhibitor of NADPH oxidase activation

Dinitrosyl iron complexes with cysteine. kinetics studies of the formation and reactions of dnics in aqueous solution

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Physical-chemical characterization of biomass samples for application iin pyrolysis process

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Micro-arc oxidation as a tool to develop multifunctional calcium-rich surfaces for dental implant applications

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

Electrochemical oxidation of landfill leachate in a flow reactor: optimization using response surface methodology

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Nanoelectrocatalytic oxidation of lactic acid using nickel nanoparticles

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

Hypobromous acid, a powerful endogenous electrophile: Experimental and theoretical studies

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