Targets Of Cu Research Articles

Toxicity of Copper on Isolated Liver Mitochondria: Impairment at Complexes I, II, and IV Leads to Increased ROS Production

Oxidative damage has been implicated in disorders associated with abnormal copper metabolism and also Cu(2+) overloading states. Besides, mitochondria are one of the most important targets for Cu(2+), an essential redox transition metal, induced hepatotoxicity. In this study, we aimed to investigate the mitochondrial toxicity mechanisms on isolated rat liver mitochondria. Rat liver mitochondria in both in vivo and in vitro experiments were obtained by differential ultracentrifugation and the isolated liver mitochondria were then incubated with different concentrations of Cu(2+). Our results showed that Cu(2+) induced a concentration and time-dependent rise in mitochondrial ROS formation, lipid peroxidation, and mitochondrial membrane potential collapse before mitochondrial swelling ensued. Increased disturbance in oxidative phosphorylation was also shown by decreased ATP concentration and decreased ATP/ADP ratio in Cu(2+)-treated isolated mitochondria. In addition, collapse of mitochondrial membrane potential (MMP), mitochondrial swelling, and release of cytochrome c following of Cu(2+) treatment were well inhibited by pretreatment of mitochondria with CsA and BHT. Our results showed that Cu(2+) could interact with respiratory complexes (I, II, and IV). This suggests that Cu(2+)-induced liver toxicity is the result of metal's disruptive effect on liver hepatocyte mitochondrial respiratory chain that is the obvious cause of Cu(2+)-induced ROS formation, lipid peroxidation, mitochondrial membrane potential decline, and cytochrome c expulsion which start cell death signaling.

Copper toxicity to Phaeodactylum tricornutum: a survey of the sensitivity of various toxicity endpoints at the physiological, biochemical, molecular and structural levels

Copper (Cu) is one of the most toxic metals in phytoplankton but the toxicity mechanisms of this metal are still not fully understood. This study examines the toxicity targets of Cu in the modeled marine diatom, Phaeodactylum tricornutum, at the physiological (cell division, DNA cell cycle), biochemical [pigments synthesis, reactive oxygen species (ROS) and malondialdehyde (MDA)], structural (subcellular observation by flow cytometry) and molecular (transcription of several metalloprotein genes) level. Cu toxicity was detectable at all these levels after 48 h of exposure to ≥20 μM total initial added Cu. The order of sensitivity of all the studied Cu toxicity endpoints was: G2/M phase > MDA > metalloproteins RNA of the photosynthetic electron transport chain (ETC) > metalloproteins RNA of the respiratory chains > G0/G1 phase > pigments ≈ S phase > propidium iodide > estimated cell yield > ROS. The relatively sensitive decrease of the transcription of metalloproteins RNA of the ETC in response to Cu exposure, if associated to an effective decrease in the expression of the proteins composing the ETC, may help to initially mitigate the ROS-mediated toxic effects of Cu in P. tricornutum. However, this cellular response to Cu was only transitory and the transcription of virtually all genes involved in redox electron transfer chains was up-regulated within an interval of 2 days. This study brings new insights into the cellular mechanisms of Cu toxicity by documenting the sensitivity and kinetics of multiple Cu-cellular targets in one marine alga.

Highly surface-textured and conducting ZnO:Al films fabricated from oxygen-deficient target for Cu(In, Ga)Se2 solar cell application

Highly conducting ZnO:Al (AZO) films are normally prepared through substrate heating and post-annealing in reducing atmosphere, which is deleterious to maintain the high transparency of films and the overall so­lar cell performance. Here we fabricate AZO films through one-step sputtering at room temperature using oxygen-deficient targets prepared via double crucible method. The best-performed AZO film achieves a low resistivity of 4.4 × 10-4 . cm, a high haze factor of 35.0%, and optimizes the efficiency of Cu (In, Ga)Se2 solar cell with a high value of 14.15%. This letter demonstrates that oxygen deficiency can induce high surface texture, conductivity, and boost solar cell performance.

Structural and electrical properties of radio frequency magnetron sputtered Cu(InxGa1 − x)Se2 thin films with additional post-heat treatment

Cu(In1−xGax)(Se,S)2 (CIGSS) thin films were deposited using a single quaternary target of Cu(In0.75Ga0.25)Se2(CIGS) by rf magnetron sputtering, followed by sulfurization. The effects of substrate temperature and post-sulfurization on the properties of CIGSS films were investigated. As the substrate temperature increased, the crystallinity of the films increased significantly and the grain size also increased. Energy dispersive X-ray spectroscopy of CIGS films showed that Cu, Ga and Se contents approached the stoichiometry of CIGS films with increasing substrate temperature.Post-sulfurization of as-deposited CIGS films was carried out to improve their properties. The resultant CIGSS thin films revealed a noticeable increase in (112) peak for films deposited under 200°C, while the intensities of the (220)/(204) and (312)/(116) peaks increased as well. Grains with a size of approximately 100nm were grown after sulfurization. The results of EDX of CIGSS thin films after sulfurization indicated that the Cu content increased slightly and the Ga and (Se+S) contents decreased significantly. The band gaps of the films were also noticeably reduced after sulfurization. The carrier concentrations of the films after sulfurization decreased greatly at substrate temperatures below 400°C, while they showed little change at temperatures above 400°C. The resistivity of the films after sulfurization increased with increasing substrate temperature and showed little change at temperatures above 400°C. As a result, CIGS films were transformed to the chalcopyrite phase with well crystallized grains through sulfurization.

Electromagnetic and geometric characterization of accelerated ion beams by laser ablation

Laser ion sources offer the possibility to get ion beam useful to improve particle accelerators. Pulsed lasers at intensities of the order of 108W/cm2 and of ns pulse duration, interacting with solid matter in vacuum, produce plasma of high temperature and density. The charge state distribution of the plasma generates high electric fields which accelerate ions along the normal to the target surface. The energy of emitted ions has a Maxwell–Boltzmann distribution which depends on the ion charge state. To increase the ion energy, a post-acceleration system can be employed by means of high voltage power supplies of about 100kV. The post acceleration system results to be a good method to obtain high ion currents by a not expensive system and the final ion beams find interesting applications in the field of the ion implantation, scientific applications and industrial use. In this work we compare the electromagnetic and geometric properties, like emittance, of the beams delivered by pure Cu, Y and Ag targets. The characterization of the plasma was performed by a Faraday cup for the electromagnetic characteristics, whereas a pepper pot system was used for the geometric ones. At 60kV accelerating voltage the three examined ion bunches get a current peak of 5.5, 7.3 and 15mA, with a normalized beam emittance of 0.22, 0.12 and 0.09πmmmrad for the targets of Cu, Y, and Ag, respectively.

Configuration and calibration of a flat field grating spectrometer in the wavelength range 7–60 Å with a Manson ultrasoft x-ray source

An ultrasoft x-ray and extreme ultraviolet spectrometer built and calibrated in the wavelength range of 7–60 Å is reported here. Details of the alignment of this flat field spectrometer with both a laser and a telescope are presented. The light path function rather than a standard calibration function, i.e. a polynomial function, is introduced as the fit function, which gives good agreement with the spectrometer design values and makes the calibration more reliable when extended to the region outside the points used for calibration, compared with a standard calibration function. The calibration results of a Manson ultrasoft x-ray source (model 2) with source targets of Cu, Fe and Ti are presented with all the peaks marked.

Transparent Conductive Cu-In-O Thin Films Deposited by Reactive DC Magnetron Sputtering with Different Targets

Transparent conductive Cu-In-O thin films were deposited by reactive DC magnetron sputtering. Two types of targets were used. The first was In target covered with a fan-shaped Cu plate of the same radius and the second was Cu target on which six In grains of 1.5mm was placed with equal distance between each other. The samples were characterized with scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), UV/VIS spectrophotometer, four-probe measurement etc. SEM shows that the surfaces of all the samples are very smooth. EDX shows that the samples contain Cu, In as well as O, and different targets result in different atomic ratios of Cu to In. A diffraction peak related to rhombohedra-centered In2O3 (012) is observed in the XRD spectra of all the samples. For both the two targets, the transmittance decreases with the increase of O2 flow rates. The direct optical band gap of all the samples is also estimated according to the transmittance curve. For both the two targets, different O2 flow rates result in different sheet resistances and conductivities. The target of Cu on In shows more controllability in the composition and properties of Cu-In-O films.

Analysis of two colliding laser-produced plasmas by emission spectroscopy and fast photography

In this work two colliding laser-induced plasmas (LIP) on Cu and C were studied by means of time resolved emission spectroscopy and fast photography. The experiments were performed using two opposing parallel targets of Cu and C in vacuum, ablated with two synchronized ns lasers. The results showed an increased emission intensity from copper ions Cu II (368.65, 490.97, 493.16, 495.37 and 630.10 nm) and Cu III (374.47 and 379.08 nm) due to the ionization that occurs during collisions of Cu and C species. It was found that the optimum delay between pulses, which yields the maximum emission enhancement of Cu ions, depends on the sampling distance. On the other hand, the emission intensity of C lines, C II (426.70 nm), C III (406.99 and 464.74 nm) and C IV (465.83 nm), decreased and the formation of C 2 molecules was observed. A comparison between the temporal evolution of the individual plasmas and their collision performed by combining imaging and the time resolved emission diagnostics, revealed an increase of the electron temperature and electron density and the splitting of the plume into slow and fast components.

1127 IS THERE NEED TO A NEW HEPATITIS B VACCINE SCHEDULE IN CHILDREN WITH CELIAC DISEASE?

Material and Methods: We complexed Cu (MS Nordion) to L-histidine (Sigma) and verified the extent of complexing with chromatography. 3.7–5.5 MBq of complexed Cu-histidine was injected into healthy Long-Evans Agouti (LEA) rats, as well as mutant Long-Evans Cinnamon (LEC) rats lacking Atp7b. Radioactivity was measured in bile, blood and organ tissues after times ranging from 1h to 24h. Furthermore, rats were subjected to dynamic microPET imaging for up to 24h. The effect of acute or chronic liver injury on handling of Cu-histidine complex was determined in LEA rats treated once or repeatedly with CCl4. To identify further mechanisms in targeting of Cu, we studied Cu complexed to hepatocyte-specific ligands. Finally, dynamic microPET imaging was performed in LEC rats after transplantation of healthy hepatocytes isolated from LEA rats. Results: Cu was efficiently complexed to histidine. The complex was incorporated largely in the liver and kidney of animals followed by rapid excretion of radiocopper in bile of healthy LEA rats and not in diseased LEC rats. MicroPET data showed a mean time to peak liver activity of 13±2 min in LEA rats, but in LEC rats hepatic SUV (standard uptake value) increased over the entire period of investigation. Dynamic microPET imaging for 30–60 min was sufficient to show divergent patterns of Cu accumulation in WD (+ 35%) and loss of Cu in the healthy state (−10%). In CCl4-treated LEA rats, the kinetics or magnitude of hepatic copper excretion were unchanged or significantly different from LEC rats, respectively (p < 0.05). Enhanced hepatic targeting of Cu complexed with ligands to asialoglycoprotein receptor showed greater fractional biliary copper clearances from the liver (p< 0.05). Moreover, the assay demonstrated correction of Atp7b deficiency in LEC rats repopulated with healthy hepatocytes from LEA rats. Conclusion: Hepatic targeting of Cu will be effective for identifying abnormality in biliary copper excretion. This assay will facilitate management of Wilson’s disease.

Formation of very stable and selective Cu(ii) complexes with a non-macrocyclic ligand: can basicity rival pre-organization?

The synthesis of ligand L based on a 2,6-bis[(N,N-bis(methylene phosphonic acid)aminomethyl] pyridine scaffold is described. Potentiometry combined with UV-Vis absorption spectrophotometric titrations were used to determine the protonation constants of the ligand and the stability constants of its corresponding Cu(II), Ni(II), Zn(II) and Ga(III) cations (0.1 M NaClO(4), 25.0 °C). The physico-chemical approach revealed very large stability constants for Cu(II) complexation (logK(CuL) = 22.71(7)) reflected in a very high pCu(II) value of ∼ 15.5 (pH = 7.4, [L](tot) = 10(-5) M, [Cu](tot) = 10(-6) M), close to those measured for the strong methylphosphonate functionalized cyclen chelators. Based on a literature survey, a correlation is proposed between the pK values of branched polyamine ligands and their stability constants for Cu(II) complexation, allowing for an estimation of the latter on the basis of the protonation constants of L. Ligand L was also shown to be very selective towards Cu(II) compared to the other cations studied (ΔlogK > 4). UV-Vis spectroscopy and kinetic measurements indicated that the formation of the cupric complexes with L is very fast, which, in combination with all other properties, makes it an excellent non-cyclic target for Cu(II) radiopharmaceutical within the frame of (64)Cu positron emission tomography imaging and radiotherapy.

Fabrication and Electrochemical Characterization of Copper Selenide Thin Films by Pulsed Laser Deposition

Copper selenide, , CuSe, and , thin films have been successfully fabricated using pulsed laser ablation of mixed targets of Cu and Se. The substrate temperature was a key factor in preparing high-quality thin films of the copper selenides, with different crystalline structures and stoichiometries. Although these three kinds of compounds (, CuSe, and ) all form thin films with the same anion and cation in their chemical formula, their electrochemical properties clearly differ from each other, evidently associated with their various compositions and structures. The galvanostatic cycling measurement indicates that a cell has the best cycling performance when compared to the other two possible cells, and . The conversion reaction mechanism between (CuSe and ) and are proposed for and cell, while the cell may undergo a “displacement” reaction mechanism according to X-ray diffraction, transmission electron microscopy, and selected area electron diffraction data. These complex and unique mechanisms make copper selenides interesting materials for rechargeable lithium batteries.

Photodynamic effect of polyethylene glycol-modified fullerene on tumor.

Fullerene (Cm) efficiently generates singlet oxygen when irradiated with light, and thus should have a photodynamic effect on tumors, if it is accumulated in the tumor tissue. To explore tumor targeting of CU, we chemically modified the water–insoluble C60 with polyethylene glycol (PEG), not only to make it soluble in water, but also to enlarge its molecular size. When injected intravenously into mice carrying a tumor mass in the hack sulicutis, the C60–PEG conjugate exhibited higher accumulation and more prolonged retention in the tumor tissue than in normal tissue. The conjugate was excreted without being accumulated in any specific organ. Following intravenous injection of CorPEG conjugate or Photofrin® to tumor–bearing mice, coupled with exposure of the tumor site to visible light, the volume increase of the tumor mass was suppressed and the C60 conjugate exhibited a stronger suppressive effect than Photofrin. Histological examination revealed that conjugate injection plus light irradiation strongly induced tumor necrosis without any damage to the overlying normal skin. The antitumor effect of the conjugate increased with increasing irradiation power and Cm dose, and cures were achieved by treatment with a dose of 424 μg/kg at an irradiation power of 107 J/cm2. These findings indicate that PEG–modified cm is a candidate agent for photodynamic tumor therapy.

Monte Carlo study of ( gamma ,e gamma ) electron momentum densities

Data are reported for numerical simulations of the triple differential ( gamma ,e gamma ) cross-section for inelastic X-ray photon scattering with coincident analysis of recoil electrons from metal foils and thin crystals. Preliminary measurements and calculations have shown that the cross-section is sensitive to the three-dimensional electron momentum density distribution and Fermi surface of the target. These simulations show that a useful signal carried by unscattered recoil electrons is produced from a region near the back of the target and sits on a homogeneous background of multiply scattered electrons. Even for thick samples this background remains sufficiently low due to saturation scattering of the emergent electrons for the umklapp Fermi surfaces in transition metals to be observable with only moderate requirements in statistical accuracy. The present work examines the experimental triple differential cross-section for pseudo-single-crystal targets of Cu and details the resolution and sensitivity of the technique to umklapp regions of the Fermi surface. Figures are presented for the feasibility of measurements at the high-energy beamlines of various synchrotron laboratories.

RFA as control method of the reactive sputtering process of TiN films

In-situ X-ray fluorescence (XRF) analysis has been used to control the deposition process of Ti-N films on steel substrates during reactive sputtering. The analysis system consisted of a tungsten X-ray tube, secondary targets of Cu, Fe and Cr and a Si (Li) detector. The sputtering off the Ti target has been determined indirectly by plasma monitoring using optical emissions spetroscopy (OES) of the Ti atoms, and the film growth has been measured directly by XRF analysis of the surface mass of Ti atoms deposited on the substrate. For zero bias voltage and varying N2 flow the increment of surface mass per deposition time has been found to incrase linearly with the intensity of the OES signal of Ti. A negative bias voltage UB≥100 V changes strongly the growth rate by resputtering effects, especially in the range where stoichiometric TiN is formed.

Emission line intensities in an r.f. sputtering glow discharge system

An in situ analysis of an r.f. discharge is carried out. The relationship between the discharge parameters, composition and growth rate of the deposited thin films and the glow discharge optical spectroscopy signal is presented. Three semiconducting single-phase chalcopyrite targets of Cu(Ga, In)Se 2 were sputtered in an Ar atmosphere. The composition of the discharge was measured and it correlated with the composition of the deposited thin films. To be able to extend the determination of the film properties to different discharge conditions we have studied the variation in the optical emission with the Ar pressure and the r.f. power. The behaviour of the optical emission intensities as a function of both the Ar pressure and discharge power is explained in terms of the variation in the electron energy distrobution function.

Different cellular targets for Cu- and Fe-catalyzed oxidation observed using a Cu-compatible thiobarbituric acid assay

The widely used thiobarbituric acid (TBA) assay for oxidative damage to biomolecules fails in Cu 2+ -containing solutions due to the formation of a cloudy precipitate. The chelatin of Cu 2+ ions with EDTA or Chelex was investigated. Both prevented precipitate formation, but only Chelex allowed proper color development in the TBA assay. The Chelex modified assay could be adapted to a variety of systems, and was applied to the detection of Cu 2+/ascorbate dependent deoxyribose breakdown and oxidative damage in erythrocyte ghosts, lysates and whole cells. Using this method, it was shown that Cu 2+/ascorbate caused membrane damage in ghosts but not in whole red blood cells (RBC). Fe 3+/ascorbate, on the other hand, caused formation of TBA-reactive products even in whole RBC. When Cu 2+ and Fe 3+ were presented to isolated hemoglobin as their 1:1 nitrilotriacetate complexes, the protein bound 10–12 cupric ions per molecule, but no ferric ions. It is suggested that oxidative damage catalyzed by copper or iron ions has different cellular targets, determined by the different binding properties of the two metals to various cellular components.

Superconducting YBa 2 Cu 3 O 7 thin films grown in-situ by ion beam co-deposition

Superconducting YBCO thin films have been grown in-situ by three ion beam co-deposition sputtering. Both metal and oxide targets of Cu and Y and BaF2 and BaCO3 targets have been investigated. Film composition was determined by RBS and AES analysis. Films grown using BaF2 show flourine contamination, whereas the carbon concentration in films grown using BaCO3 is beneath the Auger detection limit. Superconducting films have been grown on SrTiO3 (Tco=78K) and on Si with SiO2 or Y2O3 buffer layers (Tco=35K).

Superconducting Yba2Cu3O7-δ Thin Films on Srtio3 and Si Grown In-Situ by Ion Beam Sputtering

AbstractSuperconducting YBa2Cu3O7‐δ (YBCO) films 100‐300nm thick have been grown in‐situ on (100) SrTiO3 at 650°C by ion beam sputtering. Targets of Cu, CuO, Y, Y2O3, BaF2, BaCO3 and YBa2Cu3O7‐δ have been studied. Uniform composition throughout the film thickness has been achieved by co‐sputtering. Films are metallic (p300=300μΩcm) and textured, with Tc onsets at 92K and Tco=82K. Jc(77K) exceeds 105 Acm‐2. Films grown in‐situ on Si with ZrOx/Y2O3 and In2O3(10 at.%SnO2) buffer layers show Tc onsets at about 90K and Tco at about 50K, annealing improves Tco to 60K with resistivities p30o=2000μΩcm and 4000μΩcm respectively.

Elastic scattering of 152Eu and 154Eu gamma rays by atoms.

Differential cross sections are reported for the elastic scattering of 344-, 411-, 444-, 723-, 779-, 868-, 964-, 1005-, 1086-, 1112-, 1275-, and 1408-keV ..gamma.. rays through scattering angles from 2/sup 0/ to 45/sup 0/ by targets of Cu, Mo, Sn, Ta, Pb, and U. The results have been compared with two sets of theoretical cross sections for Rayleigh plus nuclear-Thomson plus Delbruck scattering. The first set was interpolated from the tables of P. P. Kane et al. (Phys. Rep. 140, 75 (1986)), which are based upon exact S-matrix amplitudes for inner-shell Rayleigh scattering and use of modified form factors and photoelectric cross sections for outer-shell Rayleigh scattering; the second set was based upon modified-form-factor Rayleigh amplitudes for all electron shells. The measured cross sections agree to closer than 10% with the Kane et al. calculations and indicate that for larger scattering angles, higher photon energies, and heavier target elements the modified form factor overestimates Rayleigh scattering. At small scattering angles there is no evidence for any systematic discrepancy between experiment and the cross sections of Kane et al.

Photon and energy yields of bremsstrahlung produced by beta particles from 90Sr,90Y, and 204Tl in thick targets of Cu, Cd, Ta, and Pb.

External bremsstrahlung spectra produced by the complete absorption of \ensuremath{\beta} particles from the decay of $^{90}\mathrm{Sr}$, $^{90}\mathrm{Y}$, and $^{204}\mathrm{Tl}$ in thick targets of Cu, Cd, Ta, and Pb are measured using a NaI(Tl) detector. The photon and energy yields and energy-yield constant are calculated using the unfolded bremsstrahlung spectra. The experimental data are compared with the numerical calculations based on the formulation of Pratt and his collaborators and the Born approximation theory of Bethe and Heitler. The experimental data agree with the Elwert-corrected Bethe-Heitler theory within experimental uncertainties for Cu and Cd, and a systematic positive deviation is found for Ta and Pb. The experimental data show good agreement with the numerical screened calculations of Pratt and his collaborators. The energy-yield constant is found to exhibit an energy dependence.