Showing papers on "Chromium published in 1983"
Patent•
07 Oct 1983TL;DR: A trace element mixture suitable for use in a protein-free tissue culture medium, which comprises water-soluble compounds selected from acids, bases, and salts containing copper, iron, zinc, manganese, silicon, molybdenum, vanadium, nickel, tin, aluminum, silver, barium, bromine, cadmium, cobalt, chromium, fluorine, germanium, iodine, rubidium, zirconium, or selenium, is described in this article.
Abstract: A trace element mixture suitable for use in a protein-free tissue culture medium, which comprises water-soluble compounds selected from acids, bases, and salts containing copper, iron, zinc, manganese, silicon, molybdenum, vanadium, nickel, tin, aluminum, silver, barium, bromine, cadmium, cobalt, chromium, fluorine, germanium, iodine, rubidium, zirconium, or selenium, the compounds being devoid of any additional metals other than those present as positive ions selected from groups IA and IIA of the periodic table of elements, wherein the compounds produce a solution containing specified minimum concentrations of the listed elements when dissolved in an amount of water sufficient to produce a concentration for one of the elements equal to the corresponding minimum concentration of the one element while maintaining each remaining element at a concentration equal to or greater than the minimum concentration for the remaining element is disclosed along with cell culture media containing these trace elements and methods of culturing cells using these media.
515 citations
TL;DR: The chromatographic technique for determining the specific copper surface area of catalysts by reaction with nitrous oxide has been investigated in this paper, where the application of a single pulse of Nitrous oxide in excess of that required to oxidize an the surface copper and a temperature of 90°C has been shown to provide a reliable measurement of specific copper surfaces.
401 citations
TL;DR: From the failure to select lymphocytes directed specifically against a chromium determinant of a particular valence it is concluded that by sensitization with chromium salts of different valences a common determinant or closely related determinants are formed.
345 citations
279 citations
01 Jan 1983
TL;DR: The redox chemistry of chromium(VI) is discussed with respect to the cellular metabolism of the carcinogen chromate in vivo and some redox proteins are active in reducing chromate.
Abstract: The redox chemistry of chromium(VI) is discussed with respect to the cellular metabolism of the carcinogen chromate in vivo. Possible sites for cellular reduction of chromium(VI) to chromium(III) are considered. The reactions of amino acids, ascorbic acid, carboxylic acids, thiol-containing mole-cules and other small molecules with chromate under physiological conditions are presented. In general only ascorbate and those molecules containing sulfhydryl groups are capable of easily reducing chromate at pH 7.4. Thus, in the cytoplasm, glutathione, cysteine and ascorbate are likely candidates to react with chromate. While most proteins are unreactive toward chromate, certain redox proteins are active in reducing chromate. The heme proteins hemoglobin and cytochrome P-450 possess chromate-reductase activity, whereas cytochrome c and myoglobin are inactive. The NADPH-dependent flavoenzymes glutathione reductase and NADPH-cytochrome P-450 reductase also possess chromate-reductase activity. However, the NAD(P)H enzymes, isocitrate dehydrogenase, glutamate dehyrogenase and malate dehydrogenase do not reduce chromate. Both microsomes and mitochondria possess chromate-reductase activity. The microsomal activity is accounted for by the NADPH-cytochrome P-450 reductase/cytochrome P-450 system. The enzyme(s) responsible for the mitochondrial reduction of chromate have not been identified. Chromium(VI) and its metabolite chromium(III) inhibit the normal activities of enzymes which bind chromium(III) or reduce chromate. The metabolism of chromate involves the generation of reactive intermediates which ultimately bind to cellular constituents and damage their function in the cell.
247 citations
202 citations
197 citations
TL;DR: In this article, the authors propose a formation d'especes contenant Cr 3+ (aq), Cr 2(OH) 4 4+ (q), Cr 3 (OH) 6 6+ q, Cr 4 (OH), 4 5+ q and 4 6+q.
Abstract: Formation d'especes contenant Cr 3+ (aq), Cr 2 (OH) 4 4+ (aq), Cr 3 (OH) 4 5+ (aq) et Cr 4 (OH) 6 6+ (aq). Valeurs des pKa. L'ordre de stabilite est dimere >tetramere
195 citations
TL;DR: The purpose of this experiment was to measure the amounts of nickel and chromium released from a simulated orthodontic appliance incubated in 0.05 percent sodium chloride solution, and the average release was 40 micrograms nickel and 36 microgramS chromium per day for a full-mouth appliance.
192 citations
TL;DR: The results suggest that the metabolism of chromium(VI) is necessary in order for chromium to interact significantly with nucleic acids.
160 citations
01 Jan 1983
TL;DR: In this article, the distribution of manganese and chromium can be influenced by the oxygen minimum zone, and the changes in oxidation state can influence input and removal in the ocean.
Abstract: The study of the different oxidation states of trace metals can put limits on the oxidation state of seawater. In addition, the changes in oxidation state can influence input and removal in the ocean. Manganese and chromium form a contrasting pair with opposite tendencies. Under oxidizing conditions Mn(IV) is scavenged as MnO2 while Cr(VI) is soluble as CrO4 2−. Under reducing conditions Mn(II) is soluble as Mn2+ while Cr(III) is removed as Cr(OH)3. Thus the distributions of manganese and chromium can be influenced by the oxygen minimum zone.
01 Jan 1983
TL;DR: The most important and most costly industrial disease is contact dermatitis and the most common cause of that is chromate sensitivity as mentioned in this paper and this collection of monographs, edited by Dr Desmond Burrows is timely and fills an important gap in our literature.
Abstract: THE most important and most costly industrial disease is contact dermatitis and the most common cause of that is chromate sensitivity. This collection of monographs, edited by Dr Desmond Burrows is timely and fills an important gap in our literature. Chrome is very widely used in industry and its use is increasing yearly, no less than 124 different jobs in industry where workers are exposed to the toxic affects of chrome are known.
TL;DR: In this paper, the authors studied the thermal activation of Cr/silica and Cr/ silica-titania polymerization catalysts and found that both the activity and molecular weight of the polyethylene formed depended on the activation temperature, suggesting a connection with the surface hydroxyl population surrounding each active center.
TL;DR: In this paper, four different measurement techniques: EPR, NAA, DLTS, and luminescence were applied to characterize the properties of chromium in silicon and its pairing reaction with boron was studied.
Abstract: Four different measurement techniques: EPR, NAA, DLTS, and luminescence were applied to characterize the properties of chromium in silicon. The solubility of chromium in silicon was determined and its pairing reaction with boron was studied. The energy level atEc−0.23 eV was attributed to interstitial chromium and a second level atEv+0.27 eV was correlated to chromium-boron pairs. The luminescence band of the chromium-boron pairs was clearly identified. The properties of chromium are compared with those of other transition metal impurities in silicon crystals.
TL;DR: In this article, X-ray diffraction analysis revealed the presence of supersaturated solid solutions of carbon and nitrogen in chromium for concentration of carbon up to several weight per cent with no detectable nitride and carbide formation as would be predicted from binary Cr-C and Cr-N phase diagrams.
TL;DR: In this article, the authors present an ion-exchange preconcentration of a poly(4-vinylpyridine) film from a 0.15 M sodium fluoride electrolyte buffered at pH 3.5.
TL;DR: EDTA significantly reduced the number and severity of patch test reactions to nickel sulphate but not those to potassium dichromate or trivalent chromium, and the minimum level of each metal required to provoke a patch test reaction was considerably greater than that found in fabric washing powder solutions.
Abstract: Minimum eliciting levels of nickel have been estimated in 25 nickel-sensitive subjects, and of chromium in 14 chromium-sensitive subjects by patch tests with aqueous solutions of the respective metals. The minimum level of each metal required to provoke a patch test reaction was considerably greater than that found in fabric washing powder solutions and was in the majority of patients tested of the order of 112 ppm nickel (0.05% nickel sulphate) or 885 ppm hexavalent chromium (0.25% potassium dichromate). One nickel-sensitive subject and one chromium-sensitive subject reacted to 1 ppm of the respective metal. Fabric washing powder did not significantly alter the patch test reaction to nickel sulphate or provoke reactions in nickel- or chromium-sensitive subjects. EDTA significantly reduced the number and severity of patch test reactions to nickel sulphate but not those to potassium dichromate or trivalent chromium.
TL;DR: After chromium supplementation 24-h urinary chromium excretion showed a 9-fold increase indicating a positive chromium balance in the subjects, and there was no significant difference betweenchromium supplementation and placebo periods in glucose tolerance and in fasting or 2-h postglucose serum insulin levels.
TL;DR: Two patients with hemochromatosis, in which iron overload is postulated to exclude chromium transport, were found to have altered rate constants, which should be useful in assessing the metabolism and nutritional requirement of chromium(III) in humans and its importance in disease processes such as diabetes.
Abstract: Chromium(III) has been reported to be an essential trace element involved in the control of glucose metabolism by insulin. We have studied the distribution and kinetics of intravenous [51Cr]chromium(III) in six human subjects using a whole-body scintillation scanner, a whole-body counter, and plasma counting. Principal concentrations were found in the liver, spleen, soft tissue, and bone. The data were fit to a model consisting of a plasma pool in equilibrium with fast (T1/2 = 0.5–12 h), medium (1–14 days), and slow (3–12 mo) compartments, and transfer rates were calculated for exchanges between compartments. Each of the imaged organs appeared to contain varying proportions of each compartment. Two patients with hemochromatosis, in which iron overload is postulated to exclude chromium transport, were found to have altered rate constants. The results should be useful in assessing the metabolism and nutritional requirement of chromium(III) in humans and its importance in disease processes such as diabetes.
TL;DR: In this paper, metal-organic complexes were isolated from coastal seawater by adsorption onto octadecyl-bonded silica (SEP-PAK cartridges) and injected into a high-performance liquid chromatograph.
Patent•
14 Sep 1983TL;DR: A typical alloy generally contains chromium, nickel, silicon, carbon, an effective cobalt content and the balance iron plus normal impurities as discussed by the authors, and may be produced in the form of castings, P/M products, hardfacing and welding materials and wrought mill products.
Abstract: A high chromium stainless steel especially suited for use as wear (galling) resisting components, for example, valve parts. A typical alloy generally contains chromium, nickel, silicon, carbon, an effective cobalt content and the balance iron plus normal impurities. The alloy may be produced in the form of castings, P/M products, hardfacing and welding materials and wrought mill products.
TL;DR: In this article, a systematic study of the oxidation of pure iron-chromium-aluminum alloys at 800°C, in pure oxygen, at a pressure of 200 Torr was presented.
Abstract: A systematic study is presented of the oxidation of pure iron-chromium-aluminum alloys at 800°C, in pure oxygen, at a pressure of 200 Torr. Oxidation characteristics are described with reference to kinetic measurements, scale topographies and morphologies, and also possible growth mechanisms. An oxide map is used to show that alloys may be classified into four categories depending on the external scale that forms: Fe2O3, Cr2O3, Al2O3, or Al2O3 with iron-oxide nodules. Alloys containing less than 2–2.5 wt. % aluminum formed either Fe2O3 or Cr2O3 as an external scale, depending on the chromium content, and internal, rod-like protrusions of Al2O3. At higher aluminum concentrations, Al2O3 was always present as an external scale, although this was interspersed by iron-oxide nodules at chromium concentrations of less than 5 wt. %. A model based on Wagner's secondary getter concept is proposed for eliminating nodule nucleation. Evidence is also present that indicates that at 800°C, alumina scale decohesion occurs prior to void formation and that voids are the result of thermal etching beneath lifted scales.
TL;DR: Results indicate that LMCr plays an important role in the detoxification and excretion of chromium in mammals and remarkably reduced the mortality rates of mice acutely poisoned with chromium chloride.
TL;DR: The pitting resistance of a series of experimental stainless steels with varying amounts of nickel, chromium, molybdenum, manganese, and nitrogen was investigated in this article.
Abstract: The pitting resistance of a series of experimental stainless steels with varying amounts of nickel, chromium, molybdenum, manganese, and nitrogen and a number of commercial stainless steel...
TL;DR: In this article, cyclopentadienyltricarbonylmethyl derivatives of chromium, molybdenum, and tungsten have been prepared and their chemistry studied.
TL;DR: In this paper, the authors present the result of an experiment experimentale realizee sur des catalyseurs sur ou sans support preparees a partir de solutions de nitrates de fer et de chrome.
Abstract: Presentation des resultats d'une etude experimentale realisee sur des catalyseurs sur ou sans support preparees a partir de solutions de nitrates de fer et de chrome
TL;DR: The ternary nitride, Li9CrN5, has been identified as the product of the reaction of paniculate chromium with nitrogen dissolved in liquid lithium, using X-ray powder diffraction (solid-state chemistry) and electrical resistivity (solution chemistry) methods; the minimum nitride activity required for the formation of this material is less than 0.0025 at 475°C as discussed by the authors.