Showing papers on "Copper published in 1977"
352 citations
TL;DR: In this paper, a computer simulation of the metal-ion binding to low-molecular-weight ligands in human blood plasma was performed, and the results showed that ternary zinc citrate complexes were more important than binary complexes.
Abstract: An investigation by computer simulation into the nature of the metal-ion binding to low-molecular-weight ligands in human blood plasma is described. Although the absolute concentrations of the metal-complex species are controlled by protein binding, the percentage distribution of transition-metal ions amongstthe low-molecular-weight ligands is not. Hence errors arising from the omission of protein–metal equilibria are successfully by-passed. The distribution of Ca2+, Mg2+, Mn2+, Fe3+, Cu2+, Zn2+, and Pb2+ amongst 5 000 complexes formed with 40 ligands has been computed. In order to cope with multicomponent systems of such a large size, a computer program has been developed. Ternary complexes account for the larger percentage of CuII and FeII species, all the former involving histidinate and all the latter, citrate. Binary complexes are favoured by CaII, MgII, and MnII. Zinc(II) and PbII form both binary and ternary complexes amongst the predominant species. In contrast with earlier work, ternary zinc citrate complexes are found to be important.
294 citations
TL;DR: In this paper, a linear absolute dilatometer based on a threeterminal parallel-plate capacitor design was used to obtain thermal expansion data for high-purity copper and aluminum from 5 to 320 K.
Abstract: A linear absolute dilatometer based on a three‐terminal parallel‐plate capacitor design has been used to obtain thermal expansion data for high‐purity copper and aluminum from 5 to 320 K. These data have an absolute accuracy of ±0.1% above 20 K for copper and above 30 K for aluminum, and agree well with published data at the higher temperatures. The disagreement which exists with other data below 5 K for copper and below 15 K for aluminum is believed to be sample dependent, but the mechanism is not known. The aluminum results in this region depend on the state of annealing of the sample.
224 citations
TL;DR: In this article, the chemical diffusion coefficients and the solubility limits of copper in iron were determined in the temperature range 690-1050 C by electron probe microanalysis.
Abstract: The chemical diffusion coefficients and the solubility limits of copper in iron were determined in the temperature range 690–1050 °C by electron probe microanalysis. Specimens were large‐grained polycrystals for the γ‐iron and single crystals for the α‐iron. The iron contained less than 11 wppm of impurities and had a resistivity ratio R293 °K/R4.2 °K up to 8700. The results for the diffusion coefficients are (in cm2/s) DγCu=0.19 exp(−65 100/RT) and DαCu=300 exp(−67 800/RT). An anomalous decrease of the diffusion below the Curie point was observed.
204 citations
TL;DR: In this paper, the effects of carbonate-bicarbonate, orthophosphate, and pyrophosphate on the toxicity of copper (II) to Daphnia magna were studied at constant pH and total hardness.
190 citations
TL;DR: In this paper, the authors measured dissolved electroactive concentrations of zinc, cadmium, lead and copper in river Rhine and North Sea samples at natural and lower pH values by differential pulsed anodic stripping voltammetry using a Kemula-type hanging mercury drop electrode.
178 citations
TL;DR: The stacking-fault energies of a number of copper alloys with electron-atom ratios less than or equal to 1·10 have been measured from observations of single dissociated dislocations imaged as discussed by the authors.
Abstract: The stacking-fault energies of a number of copper alloys with electron-atom ratios less than or equal to 1·10 have been measured from observations of single dissociated dislocations imaged...
172 citations
TL;DR: In this article, the authors studied the epitaxial growth of vapor-deposited crystalline phthalocyanine films on single-crystal copper substrates using low-energy electron diffraction.
Abstract: Monolayer structures and epitaxial growth of vapor‐deposited crystalline phthalocyanine films on single‐crystal copper substrates were studied using low‐energy electron diffraction At monolayer coverage, ordered layers of copper‐, iron‐, and metal‐free phthalocyanines were observed on both Cu(100) and Cu(111) With increasing film thickness, ordered multilayer structures of these phthalocyanines were also seen on both substrates at 300 K surface temperature All three phthalocyanines had identical monolayer and multilayer surface structures on Cu(100) On the Cu(111) substrate, the three phthalocyanines exhibited slightly different surface structures, indicating the importance of the central metal atom in the interaction with the substrate that influences the monolayer surface structure and the ordering during crystal growth The multilayer crystalline films did not have surface structures characteristic of the bulk crystal structure but rather had a surface unit mesh compatible with a single molecule per unit mesh, oriented parallel to the surface Electron beam damage and space charge effects were negligible for film thicknesses up to 500–1000 A
158 citations
TL;DR: In this paper, a copper-tolerant strain of the common unicellular green alga Chlorella vulgaris was found to exclude copper from its alga cells.
Abstract: ORGANISMS isolated from environments polluted by heavy metals are often tolerant of those metals1–5. Tolerance is usually accompanied by metal uptake equal to or greater than that of non-tolerant organisms2,6–10; the accumulated metals seem to be chemically detoxified and/or physically sequestered to render them inactive2,6,7,11–13. Because heavy metal tolerant algae10, plants2, yeast7 and invertebrates8,10 have been found not to restrict metal uptake, metal exclusion has been considered a rare mechanism of tolerance6. I report here, however, that a copper-tolerant strain of the common unicellular green alga Chlorella vulgaris excludes copper.
156 citations
TL;DR: In this paper, a new process for separating and concentrating metals is described, based on the principle of coupled transport, which is carried out within a microporous merebrane containing within its pores an organic, water-immiscible complexing agent, acting as a shuttle, picking up metal ions on one side of the membrane, carrying them across the membrane as a complex, and preserving electrical neutrality by carrying hydrogen ions in the opposite direction.
151 citations
TL;DR: Transition metal alkynyl complexes have been prepared conveniently in high yields under mild conditions by the direct reaction of acetylenes with metal halides in the presence of catalytic amounts of copper(I) iodide in diethylamine.
Abstract: Transition metal alkynyl complexes have been prepared conveniently in high yields under mild conditions by the direct reaction of acetylenes with metal halides in the presence of catalytic amounts of copper(I) iodide in diethylamine.
TL;DR: In this article, a physical model describing the codeposition mechanism of inert particles from electrolytic baths was proposed, which was based on two successive adsorption steps, and the authors demonstrated the validity of that mechanism for the co-position of alumina and copper from acidified copper sulfate plating baths.
Abstract: In 1972 Guglielmi proposed a physical model describing the codeposition mechanism of inert particles from electrolytic baths. The proposed mechanism was based on two successive adsorption steps. The present authors demonstrated the validity of that mechanism for the codeposition of alumina and copper from acidified copper sulfate plating baths. From an experimentally derived relationship between electrolytic conditions and codeposition, the importance of the reduction of copper ions adsorbed onto is shown. The influence of monovalent cations like thallium is discussed based on the mechanism proposed by Guglielmi.
TL;DR: In this article, the results of smelting seven parcels of copper ores from well-known mining areas have been investigated by analysis of the main products, metallic copper and the slags.
TL;DR: In this paper, a liquid surfactant membrane process is considered for the separation of copper ions from dilute aqueous solutions, which is shown to work effectively, solutions ranging in concentrations from 2000 ppm copper as copper sulphate (typical of acid leach solutions) down to 100 ppm copper have been successfully processed.
Patent•
04 May 1977
TL;DR: In this article, a method for electrodepositing ductile, bright, well leveled copper deposits from an aqueous acidic copper plating bath having dissolved therein from about 0.04 to about 1000 milligrams per liter of a poly (alkanol quaternary ammonium salt) formed as the reaction product of polyalkanolamine with an alkylating or quaternization agent.
Abstract: A composition and method for electrodepositing ductile, bright, well leveled copper deposits from an aqueous acidic copper plating bath having dissolved therein from about 0.04 to about 1000 milligrams per liter of a poly (alkanol quaternary ammonium salt) formed as the reaction product of a polyalkanolamine with an alkylating or quaternization agent. The polyalkanolamine constituent typically is formed as the reaction product of a polyalkylenimine (e.g. polyethylenimine) with an alkylene oxide.
TL;DR: It was of interest to examine whether or not a low molecular weight copper-rich metal-thionein was present in biological species which received no metal pretreatment at all and from bovine fetal liver an 8 Cu 2 Zn-thionin having a molecular weight of 11 500 was successfully isolated.
TL;DR: In this paper, the electrical conductivity of AsF5-graphite, a lamellar intercalation compound, has been investigated at room temperature, where n is the stage.
TL;DR: Copper, nickel, and cadmium can be determined in 100 ml of sea water by coprecipitation with cobalt pyrrolidinedithiocarbamate and graphite atomizer atomic absorption spectrometry as mentioned in this paper.
TL;DR: In this paper, the authors used 1 m H2SO4-1m NaCl and 1 m NaCl solutions to recrystallize the barite-pyrite geothermometer at the Yauricocha copper deposit, Peru.
TL;DR: In this article, a study of the copper and zinc-binding proteins in the livers from sheep foetuses of 80-142 d gestational age was made, where Metallothionein was found to constitute the major Zn-binding component in the cytosol at all times and to be identical to Znthionein from adult sheep liver.
Abstract: 1. A study has been made of the copper- and zinc-binding proteins in the livers from sheep foetuses of 80-142 d gestational age. 2. Metallothionein was found to constitute the major Zn-binding component in the cytosol at all times and to be identical to Zn-thionein from adult sheep liver. 3. Zn also occurred in two fractions, not normally found in sheep liver, with approximate molecular weights of 28000 and 47000. The relative proportions of these were age-dependent. 4. Between 15 and 35% of the hepatic Cu, corresponding to most of the Cu in the cytosol, also occurred in the metallothionein-containing fraction.
TL;DR: In this paper, the interacting effects of ascorbic acid and metal ions on carotene oxidation were studied in an aqueous Carotene-linoleate solution at pH 7.
Abstract: The interacting effects of ascorbic acid and metal ions on carotene oxidation were studied in an aqueous carotene-linoleate solution at pH 7. Ascorbic acid at concentrations up to 10—3 M was a prooxidant. Fe3+ and, to a lesser extent Co2+, acted synergistically with ascorbic acid, the prooxidant effect increasing with metal concentration. Cu2+ formed a prooxidant system with ascorbic acid only at low metal concentration, but as the copper concentration was raised, inversion of activity occurred and the copper-ascorbic acid system exerted a stabilizing action on carotene. Prooxidant effects were enhanced and antioxidant effects weakened in the presence of added lmoleate hydroperoxides. The latter were unstable in the presence of ascorbic acid and especially ascorbic acid + Cu2+. Ascorbic acid itself became unstable in the presence of Cu2+. Oxygen depletion, brought about by the rapid oxidation of ascorbic acid, may be partly responsible for the carotene-stabilizing effect of the Cu*+-ascorbic acid couple. It is postulated that additional stabilization results from the radical-scavenging properties of copper or of a copper chelate formed by ascorbic and/or dehydro-ascorbic acid.
TL;DR: In this paper, the electrical conductivity of graphite powder with antimony pentafluoride in a copper tube and swaging the sheathed compound into wire was examined.
Abstract: The electrical conductivity in graphite measured normal to the crystallographic c-axis is observed to increase after intercalation with acid molecules which act as acceptors. This behaviour is regarded as the result of ionization of the acid molecule which, in turn, increases the positive current carriers in the host graphite. Since the carrier density depends on the degree of ionization of the acid, it follows that the stronger the acid the greater the increase in carrier concentration, and assuming no adverse mobility effects, the greater the electrical conductivity. The hydrogen fluoride-antimony pentafluoride system produces some of the strongest acid substances known. The experiments described here represent the initial examination of the electrical conductivity resulting from intercalation of this material into graphite. The experiments consisted of intercalating graphite powder with antimony pentafluoride in a copper tube and swaging the sheathed compound into wire. The measured conductivity of the graphite intercalation compound, when the copper conductivity is subtracted out and allowance is made for departure from ideal density, is about 1×106 Ω−1 cm−1. This is approximately 40 times the conductivity of pristine graphite and more than one and a half times the conductivity of pure copper.
TL;DR: Raritan Bay was used as a study site to investigate the relationship between copper and lead concentrations in water and in seaweeds as discussed by the authors, showing that there is a high degree of correspondence between levels of these metals in both water and algal tissue.
TL;DR: Animals fed vitamin-enriched algae were less sensitive to a chronic copper stress than animals fed a trout-granule diet and the mechanism of toxic action is different for acute and chronic toxicity, suggesting that the ratio between chronic and acute toxicity would not be a constant under different environmental conditions.
Abstract: SUMMARY. Daphnia magna was maintained on two diets and exposed to acute and chronic copper stresses. Animals fed vitamin-enriched algae were less sensitive to a chronic copper stress than animals fed a trout-granule diet. This conclusion is based on the responses of cohorts as measured by survival, mean brood size and r, the instantaneous rate of population growth. Application factors were also significantly different for animals reared on the two foods (0.47 for algal-fed animals, 0.12 for animals reared on trout-granules). In contrast to chronic toxicity, 72 h LC50 values were not significantly different for animals maintained on the two foods. This suggests that the mechanism of toxic action is different for acute and chronic toxicity and that, if so, the ratio between chronic and acute toxicity would not be a constant under different environmental conditions.
TL;DR: X-ray microprobe analysis shows two different types of granule within the parenchyma cells of the prosoma of Balanus balanoides to be the familiar “zinc” granule made up of concentric layers and giving major peaks for phosphorus and zinc, and the other to be homogeneous and giving peaks for sulphur and copper.
Abstract: Balanus balanoides (L.) collected from an area with high heavy-metal run-off contained two different types of granule within the parenchyma cells of the prosoma. X-ray microprobe analysis shows one to be the familiar “zinc” granule made up of concentric layers and giving major peaks for phosphorus and zinc, and the other to be homogeneous and giving peaks for sulphur and copper. This latter granule is designated the “copper” granule. Whilst “zinc” granules are known to be composed of inorganic phosphate, various tests on “copper” granules in sections and in a granule-rich pellet have shown that the copper is probably complexed with organic matter. The tests also demonstrated the relatively, insoluble (inert) nature of these granules. Although “zinc” and “copper” granules were present together in the prosoma, atomic absorption analyses of whole bodies (prosoma+thorax) have shown the level of zinc (50.28 μg/mg dry weight) to be much higher than that of copper (3.75 μg/mg dry weight).