Variation In Copper Concentration Research Articles

Copper management strategies in obligate bacterial symbionts: balancing cost and benefit.

Bacteria employ diverse mechanisms to manage toxic copper in their environments, and these evolutionary strategies can be divided into two main categories: accumulation and rationalization of metabolic pathways. The strategies employed depend on the bacteria's lifestyle and environmental context, optimizing the metabolic cost-benefit ratio. Environmental and opportunistically pathogenic bacteria often possess an extensive range of copper regulation systems in order to respond to variations in copper concentrations and environmental conditions, investing in diversity and/or redundancy as a safeguard against uncertainty. In contrast, obligate symbiotic bacteria, such as Neisseria gonorrhoeae and Bordetella pertussis, tend to have specialized and more parsimonious copper regulation systems designed to function in the relatively stable host environment. These evolutionary strategies maintain copper homeostasis even in challenging conditions like encounters within phagocytic cells. These examples highlight the adaptability of bacterial copper management systems, tailored to their specific lifestyles and environmental requirements, in the context of an evolutionary the trade-off between benefits and energy costs.

The Impact of Breed, Testing Time and Metabolic Profile on the Variation of Copper Concentration in Sheep Blood Serum

Background: Copper supplementation in ruminants deserves special attention because of the narrow margin between deficiency and toxicity. The aim of the study was to analyse the relationship between the Cu concentration and other blood parameter values having taken into consideration their physiological limits based on the variation of copper concentration in the three different sheep breeds. Methods: Sixty sheep (35±5 kg) kept on the same farm were studied: the Suffolk (n = 20), the Merino (n = 20) and the Lithuanian blackhead (n = 20). The sheep were selected according to the following parameters: 3.5±0.3 years old, not pregnant during the entire investigation period, clinically healthy. All sheep were kept under the same conditions and throughout the year, were fed at the same time the same ration balanced according to their physiological needs. Individual blood samples were collected on the same day, on monthly basis for the period of one year (April 2018 to May 2019). Blood biochemical parameters as well blood haematology and cortisol concentration were analysed.Result: The highest average value of copper concentration was found in the Merino breed. The study has shown that the lowest number of blood samples with the levels of copper meeting the physiological limit values was found in the native Lithuanian blackhead sheep at the end of the grazing period and in the Merino and the Suffolk breeds - during the coldest winter months. The increase in copper concentration could be related to the stress caused due to the changes in dietary conditions, the variations of ambient temperature and different breed response to these factors.

A computational study to explore the effects of copper doping concentration on phase stability, electronic band structure and optical properties of CsSrF3 fluro-perovskite

ABSTRACT In this work we have computed the electronic, structural, and optical properties of pure and Cu-doped cubic CsSrF3 in the context of density functional theory (DFT). The optimised lattice parameter for pure material was obtained 4.99 Å which has great correspondence to its reported value that is 4.83 Å. The concentration of copper was varied (from x = 0, 0.03, 0.11, 0.22 0.33) that led to an increase in the lattice constant of doped CsSrF3 from 4.99 to 5.150 Å. The electronic bandgap is analysed by investigating the combination of different densities of states. The bandgap of pure CsSrF3 was obtained at 5.66 eV which was direct in nature. Due to variation in copper concentration, the band gap was reduced from 5.66 to 0.727 eV which was also direct in nature. Cu as a dopant at Cs sites in CsSrF3 not only alters electronic but also affects the optical properties of the pure material. The value of pure dielectric function increased from 2.1 to 2.6 in visible region; simultaneously the value of refractive index was changed from 1.4 to 1.6. Due to low refractive index this fluoride-type material can be used for protective coating and for anti-reflection and optical properties are enhanced in lower energy regime.

Effect of Cu and Sn concentration on the performance of all-sprayed CZTS solar cell

Cu2ZnSnS4/In2S3 thin film solar cell was prepared using chemical spray pyrolysis. Influence of variation in copper concentration in precursor solution on the properties of CZTS thin films was monitored. Concentration of copper was found to have essential role in adjusting composition and crystallinity of CZTS thin films. Junction was fabricated using CZTS as absorber layer and spray pyrolysed In2S3 as buffer layer. Two sets of devices were prepared, one by varying copper concentration and the other by varying tin concentration in the precursor solution for the deposition of CZTS thin films. For both sets, In2S3 thin films were deposited as buffer layer and Ag electrodes were used for taking contacts. All the performance parameters were found to have dependence on the concentration of Cu and Sn. For getting maximum conversion efficiency, the sprayed CZTS absorber layer should have elemental ratio of Cu:Zn:Sn:S=2.5:1:0.7:12 in the precursor solution. Maximum efficiency obtained was 1.85 %.

Pengaruh Konsentrasi Tembaga dan Rapat Arus terhadap Morfologi Endapan Elektrodeposisi Tembaga

Copper deposits have been obtained by the electrolysis method using copper sulfate and sulfuric acid. The effect of copper concentration and current density on the surface morphology of copper deposits and current efficiency have been studied. The variation of copper concentration is 0.04 M and 0.8 M and the variation of current density is 2-8 A/dm2. The copper deposits will be photographed macro, weighed and characterized by Scanning Electron Microscope (SEM) to determine the surface morphology of deposits and Energy-Dispersive X-ray spectroscopy (EDX) to determine the chemical composition of deposits. The surface morphology of copper deposits in the form of compact and without nodules was reached at copper concentration is 0.8 M and the current density is 2 A/dm2 with the average of current efficiency is 96%.

Sampling considerations for surveying copper concentrations in Australian vineyard soils

The Australian wine industry has funded a study to determine the concentrations of copper in vineyard soils and to assess whether the continued use of copper-based fungicides is likely to be detrimental to the long-term agricultural sustainability of vineyard soils. Prior to the conduct of regional surveys to determine copper concentrations in vineyard soils, a preliminary study was conducted in 6 vineyards near Mildura (34°S, 142°E) (north-western Vic., Australia) to determine sampling considerations. The study investigated the distribution of copper in the soils of vineyards with 3 different histories of copper-based fungicide use: <5 years old; at least 30 years old during which time the vineyard had been ploughed and replanted; and at least 60 years old. At 3 locations in each vineyard, soil samples were collected from 2 depths (0–0.15 and 0.15–0.30 m) at 0.30-m intervals along two 1.50-m-long transects running at right angles in opposite directions from the vine trunk towards the inter-row areas. The results showed that copper concentrations were higher in the top 0.15 m of soil (P < 0.001) and declined with distance from the vine (P = 0.002). The variation in copper concentrations between vineyards was found to be much greater than the variation within vineyards (variance component of 0.7746 and 0.0893, respectively). Balancing an acceptable level of error with the resources required to collect samples, we recommend obtaining 1 composite soil sample from each vineyard in regional surveys to determine copper concentrations in vineyard soils. Sampling depth and distance from the vine should also be taken into consideration in future soil sampling depending on the objective of the study.

Evolution of internal stress and microstructure in Ti50Cu50 alloy films: influence of substrate temperature and composition

The growth stress of Ti50Cu50 alloy films on alumina substrates was measured in situ under ultrahigh vacuum conditions with a cantilever beam technique as a function of substrate temperature and variation of copper concentration. The growth stress of films deposited at low temperature is interpreted to indicate the growth of amorphous respectively nanocrystalline films. At substrate temperatures above 300 °C, a novel tensile stress contribution is interpreted to be due to the formation of a preferentially oriented film of metastable copper vacancy superstructured γ-TiCu. Finally, at substrate temperatures above 365 °C, a polycrystalline γ-TiCu film is formed.Annealing of low-temperature alloy films gives rise to irreversible tensile stress changes indicating restructuring of the films. The stress change measured when annealing a superstructured γ-TiCu film is compressive and is assigned to the transformation of the metastable superstructure to polycrystalline γ-TiCu. The magnitude of this compressive stress contribution is strongly dependent on the copper concentration, i.e., copper vacancy concentration.

Nano-electrospray and microbore liquid chromatography-ion trap mass spectrometry studies of copper complexation with MHC restricted peptides.

The formation of copper/peptide complex ions by nano-electrospray and microbore HPLC-electrospray mass spectrometry has been investigated for major histocompatibility complex (MHC) class I and class II restricted peptides. Post-column addition of copper(II) acetate following microbore HPLC-MS separation was carried out using a mixing T-piece or via the sheath flow inlet of the electrospray source. Optimal analytical conditions for copper complex ion formation were determined by variation of copper concentration, pH, nebulization gas supply and spray voltage. Tandem mass spectrometry of copper/peptide complex ions provides peptide sequence information and insight into the peptide chelation sites. Copper associated y fragment ions dominate the product ion spectrum for non-histidine containing peptides, but both b and y copper complex ions were observed for the histidine containing MHC class I associated peptide gp70.

Chemical and morphological studies of liver from eider ( Somateria mollissima) in Svalbard with special reference to the distribution of copper

Specimens of male and brooding female eider (Somateria mollissima) were collected in Svalbard. Chemical analyses revealed hepatic copper concentrations ranging from 20 to 1050 micrograms per g wet weight. This is in agreement with previous results. The selenium, zinc and cadmium values were equal to or slightly higher than previously recorded. It is suggested that the wide variation in copper concentration is a result of differences in intake of copper-containing food among the birds. High selenium intake may enhance copper accumulation. Starvation influences the concentration of zinc and also copper. Zinc concentrations were significantly higher in females. This may be secondary to starvation. The percentage of copper recovered among the soluble proteins was inversely related to the copper content. The distribution of the soluble proteins reflects a normal copper metabolism. Microscopic studies showed prominent dark granules, positive with the rubeanic acid test for copper, confined to hepatocytes. By electron microscopy, the granules appeared as large irregular, electron-dense bodies that, by X-ray microanalysis, were found to contain copper. There were no signs of liver injuries such as necrosis and fibrosis. Apparently, the eider has evolved a high capacity for copper storage.

Temperature preference as an indicator of the chronic toxicity of cupric ions to Mozambique tilapia.

Evaluation of the effects of environmental contaminants on aquatic communities has focused primarily on acute bioassays. These bioassays provide rapid and reproducible concentration response curves based on death as an endpoint. In recent years, however, emphasis has shifted towards monitoring sublethal effects of toxicants. Temperature is an easily quantifiable parameter influencing both the behavior and survival of fishes. As poikilotherms, fish use behavioral responses to help regulate body temperature. Fish thermoregulatory behavior may be altered by various toxic substances. Some researchers found that a 24 hr exposure of sublethal concentrations of copper caused a significant decrease in preferred temperature of fathead minnows (Pimephales promelas), although the results were confounded due to variations in copper concentrations. In this study, the authors examined the feasibility of using acute temperature preference tests to assess the chronic toxicity of low concentrations of free cupric ions to Mozambique tilapia, Oreochromis mossambicus (Peters).

Significance of the variation in haemolymph copper-protein ratio in the crabScylla serrata (Forskal) during different hours of the day

InScylla serrata, haemolymph copper is bound to protein and it can be more reliably determined by the 2,2′ biquinoline method than by other spectrophotometric methods. Ionic or free copper is absent from the haemolymph. The lack of significant time-of-day variation in copper concentration and the occurrence of variation in total protein concentration and copper-protein ratio, indicate fluctuations in copper-free proteins, which may either be periodically sequestered or released by the tissues during different hours of the day.

An association between the concentration of copper in whole blood and haemoglobin type in sheep

SUMMARYIn a genetically diverse flock of about 320 sheep a significant association has been found between the concentration of copper in whole blood and the haemoglobin type.Sheep were bled on four occasions over a period of 1 year, with the flock mean concentration of copper varying between 53 and 96 fig per 100 ml whole blood. The copper concentrations in whole blood from sheep of haemoglobin type B exceeded those from sheep of type A by 9, 16, 15 and 15 fig per 100 ml on the four occasions respectively. The copper concentrations from sheep of type AB were 8, 11, 7 and 7 μg higher than those from type A.Differences in the frequency of the three haemoglobin phenotypes accounted for part of the breed variation in copper concentration previously observed in the same flock, but even when that effect was allowed for, highly significant breed variation remained. When plasma instead of whole blood was examined in two other flocks from which breed variation in plasma copper concentration had been reported no association was found between the plasma copper concentration and haemoglobin type.

The distribution of copper in the liver of pigs and sheep and its effect on the value of chemical anai,yses made on biopsy samples

Abstract In the livers of pigs either given or not given a copper supplement there was no significant variation in copper concentration according to the site from which the sample was taken. In two new-born lambs examined there was a statistically significant trend towards increasing concentrations in samples between the dorsal (right) lobe to the ventral (left) lobe. This trend tended to be less, or absent, in three older sheep. Using the aspiration biopsy technique described, for sheep the site of entry was almost invariably within the middle or lower areas of the visceral surface of the dorsal lobe. Detailed examination did not reveal any serious variation in copper concentration according to the depth within the liver from which samples were taken. It was found that, despite any variation in copper content that might be present, good agreement was obtained between the mean copper concentration for repeated biopsy samples of the same liver and that for replicated representative samples from the corresponding whole liver. It is concluded that for nutritional experiments in which samples from live animals are required for copper analysis, the biopsy technique provides a satisfactory sample.

Copper concentrations in the liver and blood of sheep of different breeds in relation to swayback history

The concentrations of copper in the blood and in the liver were determined for 68 female sheep of two age classes drawn from a genetically diversified grassland breeding flock. The flock comprised three breeds, Scottish Blackface, Cheviot and Welsh Mountain, and their crosses. Some sheep were inbred and some outhred, and they included a few which had produced swayback lambs two years previously. Constants were fitted for these various factors. They accounted for a significant proportion (31 per cent.) of the total variation in copper concentration in blood, but not in liver (17 per cent.). The copper concentrations ranked in the same order of magnitude for both blood and liver (Blackface < Cheviot < Welsh), but the crossbreds showed heterosis in blood copper concentration, but not in liver. The Blackface and its crosses had a significantly lower copper concentration in the liver than the three non-Blackface groups. Ewes which had formerly produced swayback lambs had a significantly lower blood copper level, but the level in the liver was average. There was a curvilinear relationship between blood and liver copper concentration. Expressed as the correlation between blood copper concentration and the reciprocal of the copper concentration in the liver, its coefficient was r = −0·6. The regressions of blood on liver values and vice versa were not significantly different for the various breeds except those for sheep involving the Blackface breed ( b blood. liver = 0·92 ± 0·20) and those excluding the Blackface ( b blood. liver = 0·17 ± 0·07). Copper concentrations in the liver was three times as variable, in terms of the coefficient of variation, as in the blood and this may contribute to the lesser significance of genetic variation in copper concentration in the liver than in the blood.

A Quantitative Anodic Replica for Electron Metallographic Studies

The electron opacity of anodic films formed on aluminum—copper alloys in an alkaline electrolyte under well controlled conditions is a function of the copper content of the alloys. This relation permits the development of a quantitative electron optical replica for application in revealing solute distribution and for measuring solute concentration. These replicas are extremely sensitive to small variations in copper concentrations in solid solution on a finer scale than can be defined by existing electron optical methods. Application of this replica technique to a study of aged aluminum—copper alloys has revealed some new aspects of the decomposition process.