Excess Amount Of Cu Research Articles

Copper-induced Genotoxicity, Oxidative Stress, and Alteration in Transcriptional Level of Autophagy-associated Genes in Snakehead Fish Channa punctatus.

Copper (Cu) is an essential and important trace element for some significant life processes for most organisms. However, an excessive amount of Cu can be highly toxic. The present study was conducted to elucidate the oxidative stress-induced alteration in transcriptional level of autophagy-related genes in the liver and kidney tissue of fish Channa punctatus after treatment with three different sublethal concentrations of CuSO4for 28days. All the studied enzymatic and non-enzymatic oxidative stress markers viz. superoxide dismutase-SOD, catalase-CAT, glutathione peroxidase-GPx, glutathione reductase-GR, and glutathione-GSH showed an increase in their activity levels in the treated groups in a dose-dependent manner. Particularly SOD and CAT have shown a significant hike in activity levels. ROS levels in blood cells increased significantly (p < 0.05) in all the treated groups, i.e., Group II-1/20th of 96h-LC50 (0.2mg/L), Group III-1/10th of 96h-LC50 (0.4mg/L), and Group IV-1/5h of 96h-LC50 (0.8mg/L) of Cu2+ in a dose-dependent manner as compared to control (Group I). The upregulation in mRNA levels of autophagy-related genes Microtubule-associated protein 1 light chain 3 (LC3), Gamma-aminobutyric acid receptor-associated protein precursor (Gabarap), and Golgi-associated ATPase enhancer of 16kDa (GATE16), autophagy-related 5 (ATG5) was observed while mammalian target of rapamycin (mTOR) showed downregulation in the liver and kidney tissue of fish. The decrease in mTOR and increase in ATG5 gene expression projects autophagic vesicle formation due to oxidative stress. There was significant induction in micronuclei (MN) frequency in all the treated groups. The highest frequency of MN induced by Cu2+ was recorded in Group IV after 28days of the exposure period. Thus, it can be concluded that the available information about Cu2+-induced oxidative stress-mediated autophagy in the liver and kidney of fish C. punctatus remains largely unclear to date, so to fill the aforesaid gap, the present study was undertaken, which gives an insight for the mechanisms of autophagy induced by Cu2+ in fish.

Multistep resistive switching of doped Cu-TCNQ nanocrystals

The resistive switching behavior of doped copper-(7,7,8,8-tetracyanoquinodimethane) (Cu-TCNQ) nanocrystals was different from that of bulk crystal. The doped Cu-TCNQ nanocrystals took the same crystal structure as bulk crystal (Cu:TCNQ = 1:1) in spite of the different composition ratio (Cu:TCNQ = 1.3:1). The excess amount of Cu resulted in the generation of TCNQ dianions (TCNQ2–) in Cu-TCNQ nanocrystals to keep the charge balance between TCNQ and excessive Cu, which led to multistep resistive switching behavior involving multistep charge transfer of TCNQ2–.

Ethylenediaminetetraacetic Acid (EDTA) Mitigates the Toxic Effect of Excessive Copper Concentrations on Growth, Gaseous Exchange and Chloroplast Ultrastructure of Corchorus capsularis L. and Improves Copper Accumulation Capabilities.

Copper (Cu) is an important micronutrient for a plant’s normal growth and development. However, excess amount of Cu in the soil causes many severe problems in plants—which ultimately affect crop productivity and yield. Moreover, excess of Cu contents causes oxidative damage in the plant tissues by generating excess of reactive oxygen species (ROS). The present experiment was designed to investigate the phytoextraction potential of Cu, morpho-physiological features and biochemical reaction of jute (Corchorus capsularis L.) seedlings using ethylenediaminetetraacetic acid (EDTA) of 3 mM under different Cu levels (0 (control), 50 and 100 μM) in a hydroponic nutrient solution (Hoagland). Our results showed that elevated Cu rates (50 and 100 μM) in the nutrient solution significantly reduced plant height, fresh and dry biomass, total chlorophyll content and gaseous exchange attributes in C. capsularis seedlings. As the concentration of Cu in the medium increased (50 and 100 μM), the level of malondialdehyde (MDA) and oxidative stress in C. capsularis seedlings also increased, which could have been controlled by antioxidant activity in particular plant cells. In addition, rising Cu concentration in the nutrient solution also increased Cu uptake and accumulation in roots and leaves as well as affected the ultrastructure of chloroplast of C. capsularis seedlings. The addition of EDTA to the nutrient solution significantly alleviated Cu toxicity in C. capsularis seedlings, showing a significantly increase in plant growth and biomass. MDA contents was not significantly increased in EDTA-induced plants, suggesting that this treatment was helpful in capturing ROS and thereby reducing ROS in in C. capsularis seedlings. EDTA modification with Cu, although the bioaccumulation factor in roots and leaves and translocation factor for the leaves of C. capsularis seedlings has significantly increased. These results indicate that C. capsularis has considerable potential to cope with Cu stress and is capable of removing a large quantity of Cu from the Cu-contaminated soil while using EDTA is a useful strategy to increase plant growth and biomass with Cu absorption capabilities.

Possible Ferromagnetism in YCuO System

polycrystalline CuxYyOz are made through solid state reaction. Ferromagnetism is found in this YCuO system at room temperature. The ferromagnetism quite probably originates from Cu2Y2O5 , the Copper Yttrium Oxide. The average magnetic moment per Cu2+ is estimated to be 0.04μB. Itinerant electron magnetism is a rational explaination for the observed ferromagnetism. The experiment shows that the excessive amount of Cu may lead more defects and further distortion in the lattice and decrease the exchange interaction. This reminds us that the Copper Yttrium Oxide is a substance not only should be avoided in fabricating YBCO superconductors but also should be considered as a potential substance of magnetic semiconductor.

Higher alcohol synthesis from syngas over xerogel-derived Co-Cu-Al2O3 catalyst with an enhanced metal proximity

To improve metal proximity of Co-Cu-Al2O3 catalyst, xerogel-derived mesoporous Co-Cu-Al2O3 catalysts (CoCuAl-Xe) with various Co:Cu molar ratios (3:1, 2:1, 1:1, 1:2, and 1:3) were prepared by an epoxide-driven sol-gel method and applied to higher alcohol synthesis from syngas. The CoCuAl-Xe catalyst induced the formation of a composite spinel structure containing Co, Cu, and Al. At the optimal Co/Cu ratio, the Cu atoms efficiently substituted the Co2+ ions in Co3O4 to form the CuCo2O4 spinel structure. However, an excess amount of Cu induced segregation of CuO, leading to decreasing Co-Cu proximity. In higher alcohol synthesis from syngas, all the catalysts showed the linear quasi-Anderson Schulz Flory plot of carbon-containing products, which was attributed to the CO insertion mechanism in higher alcohol synthesis. Among the xerogel catalysts, 2Co1CuAl-Xe exhibited the highest CO conversion and higher alcohol yield. The Co-rich CoCuAl-Xe catalyst was disadvantageous in terms of alcohol selectivity because of a lack of CO insertion sites, and the Cu-rich one was disadvantageous in CO dissociation and led to methanol formation. The computational study suggests that high Co-Cu proximity favors CHOH* mechanism for CH* formation and promotes CO insertion reaction. Consequently, it was found that the optimal Co/Cu ratio and high Co-Cu proximity is required for high catalytic activity in higher alcohol synthesis.

Effects of Cu addition to n-type β-FeSi2/Si composite on the Si precipitation and its thermoelectric properties

We investigated the influence of Cu addition to Co-doped β-FeSi2/Si thermoelectric material. We expected the addition of Cu to accelerate the eutectoid decomposition of α-Fe2Si5 phase resulting in a finer distribution of Si secondary phase. We added 1 mass% and 2 mass% of Cu followed by the annealing process in various conditions. We obtained a significant decrease of Si size, reaching less than 100 nm for composites with 2 mass% Cu, annealed at 650 °C-2 h. Within the same amount of Cu, Si size was clearly increased after annealed at 800 °C-4 h, suggesting that the phase transition is accelerated with the existence of Cu. The thermal conductivity value was greatly reduced for sample with 2 mass% Cu, compared with the experimental value of single β-FeSi2 and calculated value from the rule of mixture. This proves that the fine distribution of Si help suppress thermal conductivity despite the high value of the Si phase itself. However, the excessive amount of Cu (2 mass%) degenerated the electrical properties of β-FeSi2/Si. Nonetheless, the sample with 1 mass% Cu annealed at 800 °C for 4 h showed the highest ZT value of 0.1, indicating that it is essential to keep the balance of Cu amount and annealing conditions towards TE performance enhancement.

Differences in the levels of pesticides, metals, sulphites and ochratoxin A between organically and conventionally produced wines

Organic products are generally recognized to be healthier and safer than conventional products. However, the actual scientific data regarding the importance of organic production on particular contaminant/additive content of wines is scarce. This study aimed to evaluate contents of pesticides, metals, sulphites and ochratoxin A in organically (org) and conventionally (conv) produced wines from eleven locations in different winegrowing regions of Croatia. All wines contained significantly lower levels of residues as compared to the maximum limits (MLs) with the exception of excessive amounts of Cu and Zn in one sample. Pb and Mg were mainly significantly less represented in org wines. There were no significant differences in the content of sulphite or ochratoxin A between org and conv wines. Significantly lower total pesticide concentrations and average number of pesticides per sample were obtained in org wines. The majority of ochratoxin A positive wines were from conv wine producers.

Mechanism of Cu(I)/Cu(0)-Mediated Reductive Coupling Reactions of Bromine-Terminated Polyacrylates, Polymethacrylates, and Polystyrene.

The mechanism of the Cu(I)/Cu(0)-mediated reductive coupling reactions of bromine-terminated polymer chain-end radicals, so-called atom-transfer radical coupling (ATRC), is studied. Poly(methyl acrylate) (PMA), poly(methyl methacrylate) (PMMA), and polystyrene (PSt), prepared by atom-transfer radical polymerization (ATRP), were activated by an excess amount of Cu(I)Br and Cu(0) in the presence of tris[2-(dimethylamino)ethyl]amine (Me6TREN), and the structural analyses of the resulting polymer products and deuterium-labeling experiments unambiguously determined the mechanism. While PMMA and PSt reacted by a radical mechanism as expected, PMA-bromide was reduced to an anionic species, which was most likely an organocopper species. Trapping experiments with TEMPO suggested that the polymer chain-end radicals were generated in all cases by the reduction of the bromine-terminated polymers by low-valent Cu species. However, the PMA chain-end radical was further reduced to the anionic species from which coupling products formed in low yield.

Chicken-manure-derived biochar reduced bioavailability of copper in a contaminated soil

Purpose Copper (Cu) contamination has been increasing in land ecosystems due to economic development activities. Excessive amount of Cu in soils is toxic to both plants and microorganisms. Biochar (BC) is known to immobilize soil Cu. The objectives of this research were to investigate the effects of chicken-manure-derived BC (CMB) on Cu immobilization, and growth of native metallophyte Oenothera picensis in a Cu-contaminated soil.

Visible light photoelectrochemical response of copper deposited titanium dioxide nanotubes

This paper presents a novel preparation of copper (Cu) deposited titanium dioxide (TiO 2 ) nanotubes in photoelectrochemical systems. The main target was improving TiO 2 applications in the areas of energy conversion under visible light. Herein, we investigated different amount of Cu deposited TiO 2 nanotubes using thermal evaporation technique. Based on the results, small amount of Cu (1.09 wt.%) showed the improvement in photoelectrochemical (PEC) response under visible light. Optimum amount of Cu deposited on TiO 2 nanotubes will inhibit recombination rate of photogenerated charge carriers and improve the charge separation and transfer under visible light illumination. However, the excess amount of Cu deposited on TiO 2 nanotubes will impede the photocurrent to flow and resulted in lower photoconversion efficiency. The reason may be attributed to the formation of composite structure on TiO 2 nanotubes that serve as defects in the Cu/TiO 2 interface by the lattice mismatch that will serve as recombination site for the charge carriers.

Optical and Electrical Properties of Size-Controlled Cu–7,7',8,8'-Tetracyanoquinodimethane Nanocrystals

We report the optical and electrical properties of Cu–TCNQ (TCNQ = 7,7',8,8'-tetracyanoquinodimethane) nanocrystals (NCs) fabricated by previously reported chemical reduction reprecipitation methods. The size of the resulting NCs ranges from 50 nm to 10 µm along the long axis. Raman experiment, X-ray photoelectron spectroscopic experiment, and elemental analysis reveal that these NCs have few TCNQ dianions due to the excess amount of Cu. The absorption of interband transition in the near-infrared region shows a blue shift, and the band gap increases with decreasing NC size. The obtained NCs show high electric conductivity, compared with typical Cu–TCNQ microcrystals, and multistep switching due to the existence of TCNQ dianions.

A case of Menkes’ disease with nephrocalcinosis and chronic renal failure

Sirs, Renal tubule disorders have been reported in Menkes’ disease (MNK) [1–5]. Among others, hypercalciuria has been observed [3, 5]. We report the details of a child with MNK and nephrocalcinosis due to hypercalciuria. A 35-day-old boy was referred to our hospital with a diagnosis of MNK. He was the third child of an unrelated couple, and a previous son had died at 11 months of age from the same disease. The diagnosis of MNK was made on the basis of the following findings: hypotonia, seizures, sparse hypopigmented hair, low serum levels of copper (Cu) (30 μg/dl, normal range 70–140 μg/dl) and caeruloplasmin (7 mg/dl, normal range 15–54mg/dl). Light microscopy of his hair showed pili torti. Subcutaneous Cu histidine therapy (350 μg/day) was initiated. With this treatment, Cu and caeruloplasmin levels were maintained within the normal ranges. When he was 7 months of age renal ultrasonography revealed multiple bladder diverticula and marked bilateral medullary hyperechogenicity suggestive of nephrocalcinosis. He had no history of calcium or vitamin D supplementation or other drugs linked to hypercalciuria. Malabsorption was ruled out. Because of the nephrocalcinosis, his renal function was investigated. On initial evaluation his blood laboratory parameters were as follows: urea 32 mg/dl, creatinine 0.46 mg/dl, sodium (Na) 140 mEq/l, potassium (K) 4.2 mEq/l, chloride (Cl) 105 mEq/l, pH 7.34, bicarbonate 22 mEq/l, calcium (Ca) 9.3 mg/dl, phosphate (P) 4.5 mg/dl, alkaline phosphatase 440 IU/l, intact parathyroid hormone (iPTH) 26 pg/ml, magnesium (Mg) 1.95 mg/dl, uric acid 1.6 mg/dl. Urinary parameters were: urine flow 4.1 ml/kg body weight per hour, specific gravity 1.015 g/l, calciuria 8.2 mg/kg per day (normal < 4 mg/kg per day), magnesiuria 1.9 mg/kg per day (normal < 2.5 mg/kg per day), uricosuria 15.5 mg/kg per day (normal < 18 mg/kg per day), tubular reabsorption of phosphate (TRP) 94.4% (normal 80–95%), proteinuria 12 mg/kg per day (normal <5 mg/kg per day), microalbumin 8 μg/min (normal <20 μg/min), β-2 microglobulin 1,575 μg/l (normal <137 μg/l), uroproteinogram tubular pattern, citraturia 267 mg/day (normal 140–900 mg/day), oxaluria 22.2 mg/day (normal 13–38 mg/day), and results for glucose and aminoaciduria were negative. Blood pressure was always within the normal ranges. Restriction of sodium intake up to 1 g/day, hydrochlorothiazide 2 mg/kg per day and potassium citrate 2 mEq K/kg per day were indicated to reduce the hypercalciuria. During 4 years of follow-up, his urinary β2-microglobulin levels rose to 8,040 μg/l and microalbumin to 188 μg/min; hypercalciuria persisted, despite treatment, and creatinine clearance decreased from 81 ml/min per 1.73 m body surface area to 58.7 ml/min per 1.73 m body surface area. An excessive amount of Cu accumulates in the proximal convoluted tubular cells of patients with MNK, and increased Cu was found in the form of Cu-metallothionein (Cu-MT) [2, 3]. Metallothioneins are low molecular weight heavy metal-binding proteins, and Cu-MT overproduction is thought to contribute to cell necrosis [6]. Proximal tubule dysfunction has previously been reported in children with MNK. Two patients in the original observation of Menkes et al. were found to have albuminuria and aminoaciduria, respectively [1]. Ozawa et al. demonstrated a high rate of excretion of urinary β2Pediatr Nephrol (2009) 24:1255–1256 DOI 10.1007/s00467-008-1104-7

Selective removal of CO in methanol reformed gas over Cu-supported mixed metal oxides

Copper catalysts supported on alumina-based mixed oxides (Cu/Al 2O 3– MO x ; M=Al, Ce, Co, Cr, Fe, Mg, Mn, Sn, Zn, and Zr) were investigated for CO removal in the methanol steam reformed gas. Cu/Al 2O 3–ZnO demonstrated excellent activity. The order of the activity for Cu/Al 2O 3– MO x with different M was Zn>Al>Cr>Mn>Mg. The highest catalytic activity is strongly related to the particle size of Cu. Spinel type Cu–Al–Zn oxides, formed after the preparation, gave rise to fine Cu particles which deposited on the support by reduction so that high catalytic activity is led by small Cu particles. Excess amount of Cu (>30 wt%) leads to low dispersion and causes formation of large particles and deterioration of catalytic activity. Although it is difficult to remove the trace CO in the reformed gas through water–gas-shift reaction, addition of O 2 to the reformed gas is effective to enhance the CO removal through CO oxidation.

Preparation and Characterization of YBa2Cu3O2-δ Films Containing an Excess Amount of Cu by Chemical Vapor Deposition

YBa2Cu3O7-δ films containing an excess amount of Cu were prepared on MgO(001) at 650-750°C by chemical vapor deposition using β-diketone metal chelates. In the films prepared at the low temperatures of 650°C and 700°C, the degree of c-axis orientation was enhanced with increase of the Cu content from Y:Ba:Cu=1:2:3 to 1:2:4, and the films with Cu-rich content showed higher Tc values than the films close to the stoichiometric composition. At the higher temperature of 750°C, a supplied excess of the Cu element affected the in-plane alignment of the grains and critical current density.

Interdiffusion in copper–aluminum thin film bilayers. I. Structure and kinetics of sequential compound formation

Interdiffusion in Cu–Al thin film bilayers at temperatures between 160 and 300 °C has been studied by a combination of glancing-incidence x-ray diffraction, Rutherford backscattering spectroscopy, and transmission electron diffraction and microscopy. A sequential intermetallic compound formation was observed in samples with an excess amount of Cu with θ-CuAl2 forming first, followed by η2-CuAl, and γ2-Cu9Al4. In samples with excess Al, the θ-CuAl2 is the first and the last phase formed. The thickening of these compounds was found to obey a parabolic relationship with time, and especially the thickening of θ-CuAl2 can be described by a prefactor of 7.4 cm2/s and an activation energy of 1.31 eV.