Showing papers on "Chromium published in 1978"
TL;DR: In this article, a method for the determination of chromium species has been developed and successfully applied to both fresh and sea water samples, which utilizes pre-concentration of total chromium, chromium(ni) and particulate chromium at natural pH with accurate and precise analysis by a single flameless atomic absorption procedure.
242 citations
TL;DR: In this article, the composition and structure of passive films formed on a series of iron-chromium alloys in de-aerated 1M H 2 SO 4 were quantitatively studied.
235 citations
TL;DR: In this article, the effect of chromium and molybdenum on the formation of the passive film of stainless steels and its corrosion resistance to the chloride ion was investigated.
Abstract: This investigation is concerned with the effect of chromium and molybdenum on the formation of the passive film of stainless steels, and its corrosion resistance to the chloride ion. The corrosion resistance to the chloride ion was estimated by the potential decay method and the measurement of the anodic polarization curve. The composition analysis of the passive film was performed by Auger Electron Spectroscopic Analysis. The following conclusions were obtained from the test results: (1) The passive film was more resistant in the environment containing chloride ions as the chromium content in the passive film increased, and (2) molybdenum was observed on AES analysis to have an effect on the increment of the chromium content in the passive film and to promote the passive film formation of stainless steels, probably adsorbing on the active metal surface in the form of molybdate.
125 citations
TL;DR: Hexavalent chromium compounds were found to be mutagenic for his − strains of S. typhimurium by inducing both frameshifts and base-pair substitutions, but addition of either microsomal fractions from rat liver or of human erythrocyte lysates resulted in a complete loss of mutagenicity.
Abstract: Hexavalent chromium compounds (sodium dichromate, potassium chromate, chromic acid, basic zinc chromate and basic lead chromate) were found to be mutagenic for his − strains of S. typhimurium by inducing both frameshifts and base-pair substitutions. However, addition of either microsomal fractions from rat liver or of human erythrocyte lysates resulted in a complete loss of mutagenicity. As confirmed by chemical analysis, reversal of mutagenicity could be ascribed to reduction of the metal to the inactive trivalent form through a simple oxido-reductive reaction. In fact, reducing agents (ascorbic acid and sodium sulfite) and metabolites (GSH, DPNH and TPNH, either directly tested or obtained by mixing G6PD with S-9 mix) prevented hexavalent chromium mutagenicity, whereas an oxidizing agent (potassium permanganate) totally inhibited reversal of mutagenicity by liver and erythrocyte preparations. Enzymic conversion appeared to be involved in deactivation processes through a large production of TPNH via the hexose monophosphate oxidative pathway and other ancillary systems. On the other hand, microsomal preparations from rat lung displayed an extremely poor inactivating effect on chromium mutagenicity, and those from rat muscle, as well as human serum or plasma, were ineffective. These findings could bear relevance for the elective localization of chromium-induced tumors in human lung and could account for the results of animal carcinogenicity tests, which generally showed the development of tumors, but only at implant sites.
114 citations
113 citations
TL;DR: The photochemische Umsetzung von Fe-pentacarbonyl and 9,10-Phenanthrenchinon in Benzol fuhrt zu dem trigonalverzerrten, oktaedrischen Komplex (Ia) as mentioned in this paper.
Abstract: Die photochemische Umsetzung von Fe-pentacarbonyl und 9,10-Phenanthrenchinon in Benzol fuhrt zu dem trigonal-verzerrten, oktaedrischen Komplex (Ia), der′ als Phenanthrenchinon-Monosolvat isoliert wird.
106 citations
103 citations
TL;DR: The chromium and cobalt concentrations in the serum of healthy individuals were determined by neutron activation analysis using irradiated samples at a flux of approximately 10(14) neutrons.
Abstract: Confusion exists about the chromium and cobalt concentrations in the serum of healthy individuals. We determined these elements by neutron activation analysis. The samples were irradiated during 12 days at a flux of approximately 10(14) neutrons.cm-2.s-1. Chromium was selectively separated by distillation after the irradiation. We obtained the following values (mean +/- standard deviation): 0.160 +/- 0.083 mug/liter for chromium, and 0.108 +/- 0.060 mug/liter for cobalt.
102 citations
TL;DR: In the rec-assay and mutation assay, hexavalent (K2Cr2O7 and K2CrO4) and trivalent Cr(CH3COO)3) compounds gave positive results, their mutagenic potential being higher in the same order of clastogenic magnitude.
Abstract: The comparative cytogenetic and mutagenic effects between trivalent and hexavalent chromium were investigated. Five chromium compounds, K 2 Cr 2 O 7 and K 2 CrO 4 containing Cr 6+ , and Cr(CH 3 COO) 3 , Cr(NO 3 ) 3 and CrCl 3 containing Cr 3+ , were examined for their ability to induce chromosomal damage in cultures of human leukocytes, for their reactivity with DNA by a rec-assay system and for mutagenicity in the E. coli Hs30R test system. Chromosome-breaking activity was significantly higher for the compounds with hexavalent than trivalent chromium, the efficiency being in the decreasing order K 2 Cr 2 O 7 > K 2 CrO 4 >> Cr(CHCOO) 3 > Cr(NO 3 ) 3 , CrCl 3 . In the rec-assay and mutation assay, hexavalent (K 2 Cr 2 O 7 and K 2 CrO 4 ) and trivalent Cr(CH 3 COO) 3 ) compounds gave positive results, their mutagenic potential being higher in the same order of clastogenic magnitude.
87 citations
84 citations
TL;DR: In this article, the (001) surface electronic structure of chromium was investigated within the tight-binding approximation in the non-magnetic and in the antiferromagnetic states, and the paramagnetic local surface density of states showed a large peak near the middle of the d band just below the Fermi level.
TL;DR: The effects of trivalent and hexavalent chromium compounds on rabbits were studied with a view toward investigating the toxic potentials of two different forms of chromium to which industrial workers or miners might be exposed.
Journal Article•
TL;DR: Treatments for 1 to 4 hr with 10-4 m potassium dichromate, a soluble hexavalent chromium salt with a strong oxidizing power, markedly reduce DNA and RNA accumulation rates in hamster fibroblasts grown in vitro (BHK line), as shown by quantitative spectrophotometric determinations.
Abstract: Treatments for 1 to 4 hr with 10 -4 m potassium dichromate, a soluble hexavalent chromium salt with a strong oxidizing power, markedly reduce DNA and RNA accumulation rates in hamster fibroblasts grown in vitro (BHK line), as shown by quantitative spectrophotometric determinations. Such inhibitory action is not immediately evident on the basis of the incorporation rates of labeled nucleosides into DNA and RNA, as dichromate affects also the relative concentrations of labeled precursors in the intracellular pool. Cichromate first stimulates and then inhibits nucleoside (mostly thymidine) uptake, whereas amino acid uptake is immediately inhibited. Actual rates of macromolecular syntheses have been calculated by taking into account the induced changes of soluble precursor concentrations; such normalized rates point out that dichromate induces a sudden blockage of DNA replication, whereas RNA and protein syntheses are secondarily inhibited. The observed cytotoxic effects of dichromate are tentatively referred to the oxidation of cell components by hexavalent chromium and thereby to the interaction of reduced trivalent chromium with specific biological ligands on cell membrane and on DNA.
TL;DR: In response to a glucose load, serum chromium levels drop in subjects with presumably inadequate chromium storage; 2) a low value of relative chromium response at the 1-hr point indicates a suboptimal chromium nutritional status.
TL;DR: In this article, the homogeneous catalysis of the water gas shift reaction (CO + H/sub 2/O reversible CO/sub 1/O + H 2 O + H 3 ) was described using basic solutions of the mononuclear metal carbonyls Fe(CO)/sub 5/ and M(CO/sub 6/(M = Cr, Mo and W).
Abstract: This paper describes the homogeneous catalysis of the water gas shift reaction (CO + H/sub 2/O reversible CO/sub 2/ +H/sub 2/) using basic solutions of the mononuclear metal carbonyls Fe(CO)/sub 5/ and M(CO)/sub 6/(M = Cr, Mo and W).
TL;DR: In this article, a method for the selective determination of chromium( VI) and chromium (III) in sea water is described, where chromium is quantitatively extracted with Aliquat-336 from weakly acidic (pH 2) sample solutions.
TL;DR: In this article, the gas phase oxidation of Inconel 600 alloy has been studied under very mild oxidation conditions, and the film composition and structure were studied as a function of oxidation time, temperature, oxygen concentration and surface topography.
TL;DR: In this paper, the concentrations of some major and minor ionic constituents of different freshwater systems are listed, and the “typical” concentration estimates are given for freshwater in general.
TL;DR: Insoluble chromite, as tested in the spot test, was spontaneously mutagenic, owing to contamination of the industrial product with hexavalent chromium, and may be useful to interpret the findings of carcinogenicity tests and to predict health hazards linked to chromium.
Abstract: Soluble trivalent chromium compounds (chromium potassium sulfate, chromium nitrate, chromium chloride, neochromium and chromium alum) were inactive for Salmonella typhimurium TA100, even at milligram amounts per plate. No effect could be detected either in the absence or in the presence of rat-liver, lung or muscle microsomal fractions, of rat-muscle mitochondria (with or without ATP), of oxidized glutathione (GSSG), or of human serum, plasma or erythrocyte lysates. Conversely, addition of a strongly oxidizing agent (potassium permanganate) resulted in toxic effects in plates incorporating more than 40–80 μg of compounds and elicited a dose-effect mutagenic response at 10–40 μg per plate. These effects could be ascribed to oxidation of chromium from the trivalent to the active hexavalent state. Insoluble chromite, as tested in the spot test, was spontaneously mutagenic, owing to contamination of the industrial product with hexavalent chromium. The results obtained may be useful to interpret the findings of carcinogenicity tests and to predict health hazards linked to chromium.
TL;DR: Plasmids determining resistance to arsenic, mercury, silver, and tellurium compounds in Escherichia coli and Pseudomonas aeruginosa were tested for resistance to 40 other metal compounds.
Abstract: Plasmids determining resistance to arsenic, mercury, silver, and tellurium compounds in Escherichia coli and Pseudomonas aeruginosa were tested for resistance to 40 other metal compounds. Resistance to trivalent boron and hexavalent chromium compounds was a property of certain P. aeruginosa plasmids.
TL;DR: X-ray photo-electron spectroscopy (XPS) studies have been made on the decorative films produced on stainless steel and on ‘Nilomag’ alloy 771.
TL;DR: Modification of a Perkin-Elmer 603 atomic absorption spectrophotometer by adding a high-intensity tungsten-halogen lamp for background correction significantly improved the detection limit for elements that have analytical wavelengths in the near-ultraviolet and visible regions.
Abstract: Modification of a Perkin-Elmer 603 atomic absorption spectrophotometer by adding a high-intensity tungsten-halogen lamp for background correction significantly improved the detection limit for elements that have analytical wavelengths in the near-ultraviolet and visible regions. Chromium in human serum and urine can be measured, with a simplified sample-handling technique, in concentrations of less than 0.1 microgram/liter. For comparison, the mean value for chromium in the serum of eight men was 0.14 microgram/liter.
TL;DR: Ion-exchanger colorimetry for chromium(VI) with 1,5-diphenylcarbohydrazide has been developed for the determination of chromium at mug/l concentrations in natural water samples.
TL;DR: Eine allgemeine Darstellungsmethode fur die Titelkomplexe (I)-(VI) stellt die Reaktion entsprechender Metallhalogenid komplexes mit Me4NB3H8 in Methylenchlorid dar.
Abstract: Eine allgemeine Darstellungsmethode fur die Titelkomplexe (I)-(VI) stellt die Reaktion entsprechender Metallhalogenidkomplexe mit Me4NB3H8 in Methylenchlorid dar.
TL;DR: Cobalt, nickel and cobalt-chromium alloy were found to be the most active and were also the most toxic for other cells in tissue culture, while the other particulate metals produced only low levels of haemolysis and in general, were well tolerated by cells in culture.
Abstract: The haemolytic action of particulate cadmium, chromium, cobalt, iron, molybdenum, nickel, tantalum, titanium, zinc and cobalt-chromium alloy is described. Cobalt, nickel and cobalt-chromium alloy were found to be the most active and were also the most toxic for other cells in tissue culture. In contrast the other particulate metals produced only low levels of haemolysis and in general, were well tolerated by cells in culture. A dual effect of particulate metals is described due firstly to a direct interaction between the particle surface and cell membrane and secondly to the possible toxic effects of dissolved metal.
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TL;DR: Genetic evidence suggests that arsenic, chromium, and molybdenum compounds may influence the accuracy of DNA repair processes in microorganisms.
Abstract: A number of metals are mutagenic in bacteria or phage. These include compounds of arsenic, chromium, copper, iron, manganese, molybdenum, platinum, and selenium. Compounds containing aluminum, antimony, arsenic, cadmium, copper, lead, mercury, nickel, and tellurium have been shown to induce chromosomal aberrations or abnormal cell divisions in animal or plant cells. Genetic evidence suggests that arsenic, chromium, and molybdenum compounds may influence the accuracy of DNA repair processes in microorganisms.