نتایج جستجو برای: chromium cr
تعداد نتایج: 59444 فیلتر نتایج به سال:
In the different compartments of the environmental chromium occurs mainly in the oxidation states (III) and (VI). Although Cr(III) is an essential trace element for humans, Cr(VI) is highly cancerogenic and mutagenic. It is, therefore, necessary for risk assessment not only to determine total chromium, but also to determine chromium species, especially Cr(VI). Hexavalent chromium can be determi...
Lung toxicity of chromium fumes (Cr fumes) was examined by a single intratracheal instillation into rats of 10.6 mg and 21.3 mg Cr fumes/kg body weight and by repeated (3 times) instillations of 10.8 mg and 21.7 mg Cr fumes/kg. The pathological changes were compared with those induced by single administrations of 3.2 mg and 19.2 mg Na2CO3 solution-insoluble fraction of Cr fumes (Cr-Fr)/kg and 2...
Chromium is an environmentally significant human carcinogen with complicated metabolism and an unknown mechanism of mutagenesis. Chromium(VI) is taken up by cells as the chromate anion and is reduced intracellularly via reactive intermediates to stable Cr(III) species. Chromium(III) forms tight complexes with biological ligands, such as DNA and proteins, which are slow to exchange. In vitro, Cr...
The present study describes management of oxidative stress induced by heavy metal chromium in marine Bacillus licheniformis (NCBI GenBank Accession NumberHM194725). It is identified that the isolate reduces 10-1500 mg/L of Cr (VI) within 24-72 h. Existence of chromium reductase in growth medium implies the possibility of enzymatic reduction of Cr (VI) to Cr (III). Nevertheless, no correlation w...
Chromium (Cr), a widespread environmental pollutant, is released from various industries including tanneries, metal cleaning and processing, chromium plating, wood processing, and alloy formation. In the developing as well as in the underdeveloped countries, the industrial effluents are released directly or indirectly into the natural water resources, mostly without proper treatment, posing a m...
The objective of this study was to examine the effect of Cr(III) (chromium chloride) and Cr(VI) (potassium dichromate) on RNA and DNA-chromium adducts formation in isolated nucleic acids and isolated pig lymphocytes. The incubation of cells with potassium dichromate and chromium chloride at concentrations of 10 and 100 microM results in binding of a 1.2-1.9 fold greater number of chromium atoms...
Chromium yeast supplementation has been studied for its ability to improve carbohydrate and lipid abnormalities. There have been some earlier literature-reported studies involving chromium supplementation amongst patients suffering diabetes, but the results would appear to be somewhat varied. Forty male Wistar rats (ten weeks old, 300 g in average body mass) were divided into one of four groups...
Due to its extensive use in industrial processes, large quantities of chromium compounds are discharged into the environment. Common approaches for the speciation of Cr employ the determination of Cr(VI) and total Cr. The focus of the present work was a separation of Cr(III) and Cr(VI) species, with a minimum of sample preparation, by keeping an eye on the more relevant and toxic Cr(VI). For th...
A rapid, reliable and accurate method for the determination of hexavalent chromium in Portland cement is developed. The proposed method includes direct spectrophotometric determination of Cr (VI) in Portland cement with 1, 2, 5, 8 Tetrahydroxyanthraquinone, (Quinalizarin, QINZ) at pH 1.5. The European Directive (2003/53/EC) limits the use of cements so that it contains no more than 2 mg·Kg of w...
Layers of Fe-Cr-C Hard facing material containing various amounts of chromium were deposited on mild steel base metal. Optical Microscope (OM), Scanning Electron Microscope (SCM) and X-ray diffraction (XRD) were used to investigate the effect of chromium content of micro structural characteristics of Fe-Cr-C hard facing layers. The M7C3 carbide refinement mechanism exists on base metal. The exp...
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