970 resultados para tetrasulphonated-manganese porphyrin
Resumo:
Chronic alcohol consumption is a major risk factor for the development of chronic pancreatitis. However, chronic pancreatitis occurs only in a minority of heavy drinkers. This variability may be due to yet unidentified genetic factors. Several enzymes involved in the degradation of reactive oxidants and xenobiotics, such as glutathione-S-transferase P1 (GSTP1) and manganese-superoxide dismutase (MnSOD) reveal functional polymorphisms that affect the antioxidative capacity and may therefore modulate the development of chronic pancreatitis and long-term complications like endocrine and exocrine pancreatic insufficiency. Two functional polymorphisms of the MnSOD and the GSTP1 gene were assessed by polymerase chain reaction and restriction fragment length polymorphism in 165 patients with chronic alcoholic pancreatitis, 140 alcoholics without evidence of pancreatic disease and 160 healthy control subjects. The distribution of GSTP1 and MnSOD genotypes were in Hardy-Weinberg equilibrium in the total cohort. Genotype and allele frequencies for both genes were not statistically different between the three groups. Although genotype MnSOD Ala/Val was seemingly associated with the presence of exocrine pancreatic insufficiency, this subgroup was too small and the association statistically underpowered. None of the tested genotypes affected the development of endocrine pancreatic insufficiency. Polymorphisms of MnSOD and GSTP1 are not associated with chronic alcoholic pancreatitis. The present data emphasize the need for stringently designed candidate gene association studies with well-characterized cases and controls and sufficient statistical power to exclude chance observations.
Resumo:
Throughout the entire experiment the electrolysis were conducted in an eight-hundred cubic centimeter beaker. An excellent circulation of the solution was assured by means of an electric stirrer, vigorous gas evolution from the anodes, and by means of a regulated feed-discharge system. By means of this balance, solution of the same impurity concentration as that of the electrolyte was fed in the cell just as fast as the discharge was syphoned out.
Resumo:
Careful examination of the literature available shows that the electrodeposition of manganese from various aqueous solutions has not been attempted to any great extent. The best method for the electrodeposition of pure manganese consists in the electrolysis of a solution containing manganous and ammonium sulphates.
Resumo:
The lead storage battery as it is used today is made up of the pasted type plates of lead dioxide, the anode, and sponge lead, the cathode, and wooden or hard rubber separators, which serve to insulate these from one another. In manufacturing these, it is desirable to keep them free from impurities.
Resumo:
It is estimated that 90 to 95% of the world’s consumption of manganese is used in the steel industry in the form of either ferromanganese or spiegeleisen. The remainder is used in the form of either salts or oxides, chloride, dioxide and monoxide.
Resumo:
Rhenium properties offer many interesting possibilities, therefore any ores containing rhenium would be of considerable value. Its close relationship to manganese in the periodic table led to the belief that manganese ores would be an excellent place to search for the metal. Investigation of the literature of rhenium revealed that no ore was known to contain more than 0.001 per cent of rhenium.
Resumo:
Manganese has been successfully electrodeposited from aqueous solutions in past years by several workers in electrochemical and electrometallurgical fields. The present work was concerned, primarily, with investigation of electrodeposition from solutions which are commercially obtainable from the hydrometallurgical or pyrometallurgical treatment of the low grade manganese deposits of this country.
Resumo:
The increase in hardness is attributed to the manganese silicide being precipitated from solid solution and deposited between crystal planes. The subsequent softening which occurs on prolonging the period of reheating is believed to be due to an agglomeration of the dispersed hardening agent.
Resumo:
The production of metallic manganese by electrolysis is of potential value for the recovery of this strategic metal from domestic deposits. These deposits are largely unsuitable for the production of ferromanganese, but they are amenable to low-cost leaching processes.
Resumo:
The use of manganese in the steel industry as a deoxidizing and desulfidizing agent makes it a necessity in modern industry, while the various alloy steels using manganese for the quality of toughness are also indispensable. Manganese is also used in the manufacture of such various articles as battery cells, paints and glass.
Resumo:
The purpose of the investigation was to determine the most effective means of concentrating the manganese in the ore. The study was that of identification of the minerals present. This showed the presence of oxides of manganese and iron, and carbonates of calcium and manganese. Methods of investigation were planned to determined whether the ore could be concentrated effectively by gravity concentration methods.
Resumo:
The subject of the thesis was based upon the theory of precipitation or age hardening of the copper by the compound formed by the Manganese and silicon present in the ternary Cu-Mn-Si alloy. The effect of the heat treatment to such an alloy was to be studied and the best aging time and temperature was to be determined.
Resumo:
Powder metallurgy is a branch of metallurgy which produces metallic compacts in their final forms by means of pressure and heat-treatment from the powders. The products of powder metallurgy are being used in our daily lives quite often. For example, the tungsten wires in the electric bulbs to the silver-tin fillings of our teeth.
Resumo:
Manganese is commonly known to be a metal of great strategic importance. It is essential in the production of all steels, first as a scavenger to remove oxygen and sulfur, and second as an alloying element in wear-resistant steels.