a simple and sensitive extractive- spectrophotometric method for thedeterrnination of trace amounts of vanadium(v) is reported. the method is based on the quantitative extraction of the anion complex of v(v) with 4-(2-pyridy1azo)-resorcinol with tetrabutylammonium perchlorate into chloroform, followed by spectrophotometric measurements at 554 nm. beer's law is obeyed over the concentration...

Vanadium compounds exert preventive effects against chemical carcinogenesis on animals, by modifying, mainly, various xenobiotic enzymes, inhibiting, thus, carcinogen-derived active metabolites. Studies on various cell lines reveal that vanadium exerts its antitumor effects through inhibition of cellular tyrosine phosphatases and/or activation of tyrosine phosphorylases. Both effects activate s...

OBJECTIVE To assess the effectiveness of oral vanadium supplementation for glycaemic control in type 2 diabetes by conducting a systematic review of the literature. DESIGN AND METHODS Eligible studies were identified by searching 14 databases using standardized terms. Experts, study authors and manufacturers were also contacted. Hand-searching was not undertaken. Selection criteria for inclus...

Solid-state wide-line, magic-angle spinning (MAS) and pulse excitation (nutation) NMR techniques are applied in a study of local environmeots in two-dimensional vanadium(V) oxide surface layers on titania and alumina supports. Two main surface vanadium oxide species with different bonding environments are detected, which are, on the basis of their anisotropic chemical shift and nuclear electric...

The work investigated the protective role of lactational vitamin E administration on vanadium-induced histotoxicity. Three groups of Wistar rats, with each group comprising of two dams and their pups, were used in this study. Group I pups were administered intraperitoneal injection of sterile water at volumes corresponding to the dose rate of the vanadium (sodium metavanadate) treated group fro...

Three different types of tungsten-containing enzyme have been previously purified from Pyrococcus furiosus (optimum growth temperature, 100 degrees C): aldehyde ferredoxin oxidoreductase (AOR), formaldehyde ferredoxin oxidoreductase (FOR), and glyceraldehyde-3-phosphate oxidoreductase (GAPOR). In this study, the organism was grown in media containing added molybdenum (but not tungsten or vanadi...

Abstract: The recovery of vanadium from sulfuric and hydrofluoric mixed acid solutions generated by the direct leaching of black shale was investigated using solvent extraction and precipitation methods. The process consisted of reduction, solvent extraction, and stripping, followed by precipitation and calcination to yield vanadium pentoxide. The influence of various operating parameters on th...

Vanadium is considered as an essential trace element in some animals. In human’s classification of vanadium as an essential nutrient is still a topic of debate among various research groups. Nutritionally vanadium is thought to be a cofactor in various enzymatic reactions. Increased levels of insulin in blood (hyperinsulinemia) associated with type-2 diabetes mellitus. Increase intake of fat in...

Figure 1, compiled from data in the US Geological Survey indicates that, in 2004, 94% of vanadium used was consumed by the steel industry and 6% by all other uses. Figures 2 and 3 show data on steel production and vanadium consumption over a number of past years. Figure 2 indicates that in 2004 steel production reached a record level of 1.036 billon tonnes, driven largely by increases in steel ...