Showing papers on "Zinc published in 1970"

Respiration and Osmoregulation in Rainbow Trout with Gills Damaged by Zinc Sulphate

Abstract: 1. Damage to the gill epithelium occurs when hatched fish are killed rapidly by solutions of zinc sulphate. 2. The rate of routine oxygen uptake by lightly sedated, quiet, rainbow trout did not alter on exposure to a rapidly toxic solution of zinc sulphate. However, oxygen utilization decreased seven-fold, gill ventilation volume increased six-fold, heart rate was halved, coughing rate increased 18-fold and the Po2 of dorsal aortic blood declined. 3. Unsedated trout usually struggled on exposure to zinc. The survival time of struggling fish was reduced and oxygen uptake increased, but other physiological changes were similar to those in quiet fish. 4. The respiratory changes in poisoned trout were generally similar to changes observed earlier in the same fish under hypoxia. 5. The osmotic concentration and the concentrations of sodium, potassium, calcium, magnesium and zinc in blood were largely unaffected by immobilization in zinc sulphate solution. Trout survived a four-fold increase in zinc concentration in the blood by injection. 6. The results suggest that epithelial damage decreased the permeability of the gills to oxygen, and did not increase their permeability to cations. Zinc was not a rapid internal poison. Death was probably caused by tissue hypoxia, when maximum gill ventilation was no longer sufficient to supply the oxygen needs of the fish.

Ligand ENDOR of Metal Complexes in Powders

Abstract: Magnetically dilute crystalline powders of the following metal complex systems have been prepared by coprecipitation: copper salicylaldoxime in palladium salicylaldoxime, copper dimethylglyoxime in nickel dimethylglyoxime, copper picolinate in phthalic acid and also in zinc picolinate, copper 2‐methylpicolinate in zinc 2‐methylpicolinate, copper quinaldinate in zinc quinaldinate, copper 8‐hydroxyquinolinate in phthalimide and also in zinc 8‐hydroxyquinolinate, and silver picolinate in phthalic acid and also in zinc picolinate. These samples have been investigated with electron–nuclear double‐resonance (ENDOR) spectroscopy. At some settings of the magnetic field, single‐crystal‐type ENDOR spectra are obtained which arise substantially from molecules in a single orientation with respect to the magnetic field. At other settings of the field, powder‐type ENDOR spectra are found which arise from molecules in many orientations. In either case the spectra are simpler and easier to interpret than the EPR powder s...

Zinc Adsorption by Calcareous Soils

Abstract: Zinc adsorption by calcareous soils , Zinc adsorption by calcareous soils , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Microbiological leaching of a zinc sulfide concentrate

Abstract: The microbiological extraction of zinc from a high-grade zinc sulfide concentrate has been investigated, using a pure strain of Thiobacillus ferrooxidans. Conditions such as temperature, pH, pulp density, nutrient, concentration, and specific surface of solids have been studied in terms of their effects on zinc extraction rate and in some instances on final zinc concentration in solution. Where appropriate, optimum conditions for leaching have been specified.

Effect of Zinc on Translocation of Iron in Soybean Plants

Abstract: Zinc interfered with translocation of iron from roots to above ground parts of Glycine max. (L.) Merrill var. Hawkeye. During periods in which zinc impeded iron translocation, it also suppressed the production of reductant by roots. Addition of iron, as a ferric metal chelate (iron ethylenediaminedihydroxyphenylacetic acid), to the growth medium overcame the interference of zinc. In the root epidermis, potassium ferricyanide formed a precipitate (Prussian blue) with ferrous iron derived from the previously supplied iron ethylenediaminedihydroxyphenylacetic acid. The reduction of ferric iron was suppressed by zinc.

Distribution of protein-bound zinc in normal and cirrhotic serum.

Abstract: The distribution of 65 Zn among the serum proteins of 18 cirrhotic patients and 10 normal individuals was studied. Total zinc was measured in each serum. Zinc was bound to albumin, transferrin and α 2 -macroglobulin in all subjects. It was bound to IgG in all cirrhotics and five of ten normals. Utilizing the percentage distribution of 65 Zn and total serum zinc, the amount bound in each fraction was calculated. Albumin-bound zinc correlated well with total serum zinc (r = 0.97). Total serum zinc was lower in cirrhotics than in normals (p α 2 -macroglobulin. The total amount bound to these proteins (Tf- α 2 M) was of remarkably constant and equivalent size in normals and cirrhotics. Transferrin concentration was significantly lower (p α 2 -macroglobulin was higher in cirrhotics although the difference was not significant (p α 2 -macroglobulin. However, the total amount bound to Tf- α 2 M remains remarkably constant even when total serum zinc falls as low as 12 μg./ml. The constancy of the amount of zinc bound to Tf- α 2 M implies metabolic control of this fraction. When serum zinc falls to very low levels, it may account for nearly one-half of the total serum zinc. It is suggested that transferrin and α 2 -macroglobulin may have an important role in internal zinc exchange.

Intoxication following ingestion of elemental zinc.

Abstract: A 16-year-old boy ingested 12 gm of metallic zinc in an attempt to hasten healing of a minor laceration. Lethargy occurred several days after the ingestion, and was accompanied by an elevated zinc concentration in whole blood. Chelation therapy promoted dramatic clinical improvement, and a fall in blood zinc levels.

Zinc Oxide-Eugenol Cements: II. Study of Erosion and Disintegration

Abstract: The continuous leaching of eugenol from zinc oxide-eugenol cements causes the weak zinc eugenolate chelate, which forms the binding matrix, to decompose and the cement to disintegrate. The relevance of specification solubility and disintegration tests is discussed.

Nutrient composition of selected wheats and wheat products. VI. Distribution of manganese, copper, nickel, zinc, magnesium, lead, tin, cadmium, chromium, and selenium as determined by atomic absorption spectroscopy and colorimetry.

Abstract: Magnesium and eight trace mineral elements, manganese, copper, nickel, zinc, lead, tin, cadmium, and chromium, were determined by atomic absorption spectroscopy in 11 known wheats or wheat blends, 20 commercially prepared flours from these wheats, and 25 specially prepared products from the flours. The same minerals were determined in ten consumer products from ten different cities. There was significant variation among the five hard wheats in their content of nickel, zinc, lead, tin, cadmium, and chromium. Manganese, copper, zinc, cadmium, and chromium varied significantly in the four soft wheat samples, most of the variation being contributed by a single low mineral wheat. The concentration of manganese, copper, zinc, and magnesium were about the same or lower and nickel, tin, cadmium, and chromium higher in the cake and crackers than in the respective flour from which they were made. Although there were significant variations in the lead, cadmium, and chromium concentrations in most of the market samples of consumer products there was no discernible effect of geographic location on the general mineral content of these products. Whole-wheat consumer products contained greater concentrations of manganese, copper, zinc, magnesium, and chromium than did products made from white flour. The selenium content of amore » small group of wheat blends and products was determined by a colorimetric method. 8 references, 7 tables.« less

High Resistivity Transparent ZnO Thin Films

Abstract: Zinc oxide (ZnO) is a material which, under ordinary circumstances, has a small oxygen deficiency. This lack of chemical makes ZnO an n-type semiconductor with a typical resistivity of 1–100 Ωcm. In this work crystalline ZnO films with resistivities from 108-1013 Ωcm have been obtained by reactively dc sputtering metallic zinc or rf sputtering ZnO in an argon-oxygen mixture or in pure oxygen. Films were deposited on metallic substrates such as gold or zinc or insulating substrates such as quartz or sapphire maintained at temperatures from −100 °–+200 °C. The high resistivity is thought to result from a decrease in the normal oxygen deficiency of ZnO. Three mechanisms are likely to be involved hi the enhanced oxygen incorporation: (1) oxygen atoms in the discharge, (2) dissociation of oxygen ions on impact with the surface, and (3) implantation of oxygen ions in the film. Although quantitative data are not available at this time it is clear that the effect of oxygen atoms is large since they are formed bot...

Effects of nitrogen, copper, and zinc fertilizers on the copper and zinc nutrition of wheat plants

Abstract: The effects of nitrogen, copper, and zinc fertilizers on dry matter yields and on copper and zinc absorption and distribution were studied in Gabo wheat plants grown in pots of an acid loamy sand from Badgingarra, Western Australia. Plants were harvested three times during vegetative growth and at maturity. Copper and zinc fertilizers had no effect on vegetative or grain yields unless nitrogen fertilizer was also added. Nitrogen fertilizer overcame symptoms of severe nitrogen deficiency and increased growth five- to eightfold. Nitrogen induced slight symptoms of copper deficiency and of zinc deficiency after 80 days' growth and induced severe symptoms of copper deficiency at maturity. Nitrogen severely depressed the concentrations of copper and zinc in plant tops and roots by diluting the absorbed copper and zinc: two effects of nitrogen on growth contributed to dilution of copper and zinc - a large increase in total growth and a marked increase in top relative to root growth. Deficiencies of copper and of zinc each depressed vegetative growth and delayed maturity: at maturity, each deficiency enhanced straw yields and depressed grain yields. Copper deficiency was aggravated by zinc sulphate, which depressed copper concentrations of tops and roots. Zinc depressed copper concentrations mainly by depressing copper absorption: it depressed the amount of copper absorbed, depressed the rate of copper absorption per gram root in early growth, and had no effect on the distribution of copper between roots and tops. The combined effects of zinc and nitrogen fertilizers induced such severe copper deficiency at maturity that they almost eliminated grain yield. Zinc deficiency was aggravated by copper sulphate, which depressed zinc concentrations of tops and roots. Copper depressed zinc concentrations in plants partly by increasing growth but primarily by depressing zinc absorption: copper depressed the amount of zinc absorbed, depressed the rate of zinc absorption per gram root in early growth, and had no effect on the distribution of zinc between roots and tops. It is suggested that nitrogen fertilizer could induce copper and zinc deficiencies in cereal crops growing on soils with marginal copper or zinc supplies. Zinc fertilizers would aggravate the effect of nitrogen on copper deficiency, and copper fertilizers would aggravate the effect of nitrogen on zinc deficiency.

Evaluation of Application Methods Efficiency of Zinc and Iron for Canola(Brassica napus L.)

Abstract: In order to evaluation of application method efficiency of zinc and iron microelements in canola, an experiment was conducted in the Agricultural Research Station of Eastern Azerbaijan province in 2008. The experimental design was a RCBD with eight treatments (F1: control, F2: iron, F3: zinc, F4: iron + zinc in the form of soil utility, F5: iron, F6: zinc, F7: iron+ zinc in the form of solution foliar application, and F8: iron + zinc in the form of soil utility and foliar application). Analysis of variance showed that there were significant differences among treatments on given traits, antioxidant enzymes activity, fatty acids percentage, plant height, seed weight to capitulum weight ratio, protein percentage, oil percentage, oil yield, 1000 seed weight, seed yield, nitrogen, phosphorous and potassium percentage of leaves, zinc and iron content of leaves and capitulum diameters. The highest seed yield, oil yield, oil percentage, 1000 seed weight, seed weight to capitulum weight ratio and protein percentage were obtained from the soil and foliar application of iron + zinc treatments (F8). Also, the highest amounts of nitrogen, phosphorous and potassium concentration in leaves were achieved from control treatment which was an indication of non-efficiency of iron and zinc on the absorption rate of these substances in the leaves. The correlation between effective traits on the seed yield, such as, capitalism diameter, number of seed rows in capitulum, seed weight to capitulum weight ratio and 1000 seed weight were positively significant. In general, foliar and soil application of zinc and iron had the highest efficiency in aspect of seed production. The comparison of the various methods of fertilization showed that foliar application was more effective than soil application. Also, micronutrient foliar application increased concentration of elements, especially zinc and iron. Antioxidant enzymes activity was different in response to treatments also the highest palmitoleic, oleic and myristic acid were observed in F6 and F7 treatments.

Copper plating on zinc and its alloys

Abstract: Production of a uniform, continuous corrosion resistant bonded copper coating on a zinc or zinc alloy body, by a process which comprises contacting the zinc or zinc alloy body with an electroless copper plating composition or solution consisting essentially of a soluble copper salt, e.g., copper sulfate, a complexing agent, e.g., citric acid, and a reducing agent, e.g., sodium hypophosphite. The resulting zinc or zinc alloy body can then be contacted with a copper electroplating bath, and according to one embodiment the resulting copper plated zinc or zinc alloy body is then treated in a nickel electroplating solution, followed by treatment in a chromic acid electroplating solution, to provide a corrosion resistant bright attractive metal coating on the zinc or zinc alloy body. The above noted novel electroless copper plating composition, and the zinc or zinc alloy article coated with an electroless copper plating.

Structural Role of Zinc Oxide in Glasses in the System Na2O‐ZnO‐SiO2

Abstract: Glasses containing 50 to 75 mol% SiO2 and up to 35 mol% ZnO were studied using thermal expansion, density, molar volume, refractive index, molar refractivity, internal friction, and infrared absorption data. Increasing the zinc oxide content in the glasses decreased the thermal expansion and increased the density, refractive index, and the activation energy for the alkali-ion diffusion internal friction peak. Infrared absorption from 1500 to 70 cm-1 indicated the presence of both six and four oxygen coordination for the zinc cation.

The acute lethal toxicity to rainbow trout of mixtures of copper, phenol, zinc and nickel†

Abstract: The acute lethal toxicities to rainbow trout, Salmo gairdneri Richardson, of mixtures of copper and phenol, of copper, zinc and phenol, and of copper, zinc and nickel, over an exposure period of 48 h were determined. The concentrations selected for testing were such that each poison theoretically contributed equally to the toxicity of the mixture. It was found that the toxicities of these mixtures could be adequately predicted by summation of the fractional toxicities of the particular poisons which were present.