Showing papers on "Copper published in 2005"
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TL;DR: This review gives a briefly overview of the current understanding of the more important features concerning copper toxicity and tolerance in plants, and brings information of recent findings on copper trafficking including copper detoxification factors, copper transporters and copper chaperones.
Abstract: Copper is an essential metal for normal plant growth and development, although it is also potentially toxic. Copper participates in numerous physiological processes and is an essential cofactor for many metalloproteins, however, problems arise when excess copper is present in cells. Excess copper inhibits plant growth and impairs important cellular processes (i.e., photosynthetic electron transport). Since copper is both an essential cofactor and a toxic element, involving a complex network of metal trafficking pathways, different strategies have evolved in plants to appropriately regulate its homeostasis as a function of the environmental copper level. Such strategies must prevent accumulation of the metal in the freely reactive form (metal detoxification pathways) and ensure proper delivery of this element to target metalloproteins. The mechanisms involved in the acquisition of this essential micronutrient have not been clearly defined although a number of genes have recently been identified which encode potential copper transporters. This review gives a briefly overview of the current understanding of the more important features concerning copper toxicity and tolerance in plants, and brings information of recent findings on copper trafficking including copper detoxification factors, copper transporters and copper chaperones.
923 citations
TL;DR: This work has developed a method for preparing highly uniform monodisperse nanocrystals of Cu(2)O, and confirmed the thin layer of CuO, which is blue-shifted, and appears to increase in energy as a function of decreasing particle size.
Abstract: It is well-known that inorganic nanocrystals are a benchmark model for nanotechnology, given that the tunability of optical properties and the stabilization of specific phases are uniquely possible at the nanoscale. Copper (I) oxide (Cu(2)O) is a metal oxide semiconductor with promising applications in solar energy conversion and catalysis. To understand the Cu/Cu(2)O/CuO system at the nanoscale, we have developed a method for preparing highly uniform monodisperse nanocrystals of Cu(2)O. The procedure also serves to demonstrate our development of a generalized method for the synthesis of transition metal oxide nanocrystals. Cu nanocrystals are initially formed and subsequently oxidized to form highly crystalline Cu(2)O. The volume change during phase transformation can induce crystal twinning. Absorption in the visible region of the spectrum gave evidence for the presence of a thin, epitaxial layer of CuO, which is blue-shifted, and appears to increase in energy as a function of decreasing particle size. XPS confirmed the thin layer of CuO, calculated to have a thickness of approximately 5 A. We note that the copper (I) oxide phase is surprisingly well-stabilized at this length scale.
845 citations
TL;DR: The biocidal properties of copper; the possible mechanisms by which copper is toxic to microorganisms; and the systems by which many microorganisms resist high concentrations of heavy metals are reviewed, with an emphasis on copper.
Abstract: Copper ions, either alone or in copper complexes, have been used to disinfect liquids, solids and human tissue for centuries. Today copper is used as a water purifier, algaecide, fungicide, nematocide, molluscicide as well as an anti-bacterial and anti-fouling agent. Copper also displays potent anti-viral activity. This article reviews (i) the biocidal properties of copper; (ii) the possible mechanisms by which copper is toxic to microorganisms; and (iii) the systems by which many microorganisms resist high concentrations of heavy metals, with an emphasis on copper.
643 citations
TL;DR: The syntheses and magnetic susceptibilities of a pure series of rare copper minerals from the atacamite family with general formula ZnxCu4-x(OH)6Cl2 (0
Abstract: The syntheses and magnetic susceptibilities of a pure series of rare copper minerals from the atacamite family with general formula ZnxCu4-x(OH)6Cl2 (0 ≤ x ≤ 1) are reported. The structure of these compounds features a corner-sharing triangular kagome lattice of antiferromagnetically coupled Cu(II) ions. We correlate the onset of magnetic ordering with the mole fraction of paramagnetic Cu(II) ions located between kagome layers and demonstrate that the fully Zn-substituted compound shows no magnetic ordering down to 2 K, resulting in a highly spin-frustrated S = 1/2 lattice.
592 citations
15 Mar 2005-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, current and heat generation gradients were evaluated in the radial and axial directions for both cases, in order to investigate current and temperature distributions under typical spark plasma sintering (SPS) conditions.
Abstract: Modeling and experimental analyses were carried out to investigate current and temperature distributions under typical spark plasma sintering (SPS) conditions. The simulation utilized two sample materials with widely differing electrical conductivities, alumina and copper. Current and heat generation gradients were evaluated in the radial and axial directions for both cases. Radial gradients result in significant differences in temperature between the surface of the graphite die and its center, in agreement with experimental measurements. Axial gradients are shown to influence the homogeneity of the product.
526 citations
TL;DR: High-quality ultralong copper nanowires can be synthesized in large scale with a facile aqueous reduction route at low cost and can be used as starting solid precursor for fabrication of polycrystalline oxide nanotubes via direct oxidation in air.
Abstract: The present difficulties in synthesis of one-dimensional copper are short length, nonlinear morphology, polydispersivity, poor crystallinity, low yield, and process complexity. In this work, we demonstrate that high-quality ultralong copper nanowires (90-120 nm in diameter, 40-50 microm in length; aspect ratio >350-450) can be synthesized in large scale with a facile aqueous reduction route at low cost. The prepared copper nanowires can also be used as starting solid precursor for fabrication of polycrystalline oxide nanotubes via direct oxidation in air.
464 citations
TL;DR: In this article, the application of chitosan-cellulose hydrogel beads as an adsorbent for Cu adsorption from aqueous solutions was examined.
460 citations
TL;DR: The corrosion behavior of FeCoNiCrCux high-entropy alloys in 3.5% NaCl solution is reported in this paper, and the corrosion resistance has been evaluated using immersion tests and potentiodynamic polarization measurements.
452 citations
IBM1
TL;DR: It is shown that cuprous intermediates near the copper surface affect the overpotential and the kinetics of plating, and the additives regulate the presence of cuprous species on the surface; levelers and suppressors inhibit Cu+ formation, whereas accelerating additives enhance Cu- formation.
Abstract: Copper plating baths used for forming integrated circuit interconnects typically contain three or four component additive mixtures which facilitate the superfilling of via holes and trench lines during damascene plating. Extensive study over the last two decades has provided researchers with an understanding of the underlying mechanisms. The role of cuprous intermediates in the copper deposition reaction has long been acknowledged, but it is not yet fully understood. In this paper we describe the results of an electrochemical study of the interaction of the organic additives used with copper and copper ions in solution. It is shown that cuprous intermediates near the copper surface affect the overpotential and the kinetics of plating. The additives regulate the presence of cuprous species on the surface; levelers and suppressors inhibit Cu+ formation, whereas accelerating additives enhance Cu+ formation. Acceleration by the bis(sodiumsulfopropyl) disulfide (SPS) additive results from accumulation of cuprous complexes near the surface. Adsorbed cuprous thiolate [Cu(I)(S(CH2)3 SO3H)ad] is formed through interaction of Cu+ ions and SPS rather than Cu2+ and mercaptopropane sulfonic acid (MPS).
429 citations
TL;DR: In this paper, a series of copper-doped zinc oxide films were grown by pulsed-laser ablation and the magnetic moment per copper atom decreased as the copper concentration increased.
Abstract: A series of copper-doped zinc oxide films were grown by pulsed-laser ablation. Films grown under conditions that produced n-type ZnO were nonmagnetic while those grown under conditions that produced p-type were ferromagnetic with a Curie temperature above 350 K. The magnetic moment per copper atom decreased as the copper concentration increased. An explanation for this result is proposed based on the distance between nearest-neighbor copper atoms.
372 citations
TL;DR: A highly selective copper(II) ion fluorescent sensor has been designed based on the UV-visible absorption of a spiropyran derivative coupled with the use of a metal porphyrin operative on the fluorescence inner filter effect, which presents an excellent selectivity for copper ion in comparison with several other heavy or transition metal ions.
Abstract: A highly selective copper(II) ion fluorescent sensor has been designed based on the UV−visible absorption of a spiropyran derivative coupled with the use of a metal porphyrin operative on the fluorescence inner filter effect. Spiropyrans, which combine the characteristics of metal binding and signal transduction, have been widely utilized in cationic ion recognition by UV−visible spectroscopy. In the present work, the viability of converting the absorption signal of the spiropyran molecule into a fluorescence signal was explored. On account of overlap of the absorption band of the spiropyran (λabs = 547 nm) in the presence of copper ion with the Q-band of an added fluorophore, zinc meso-tetraphenylporphyrin (λabs = 556 nm), the effective light absorbed by the porphyrin and concomitantly the emitted light intensity vary as a result of varying absorption of the spiropyran via fluorescence inner filter effect. The metal binding characteristic of the spiropyran presents an excellent selectivity for copper ion...
TL;DR: In this article, a new recycling process of metal values from spent lithium-ion batteries was described, where after the dismantling of the spent batteries steel crusts, the leaching of battery internal substances with alkaline solution and the dissolving of the residues with H 2 SO 4 solution were carried out.
TL;DR: The presented data provide a coherent picture with strong evidence for a kinetically labile copper pool, which is predominantly localized in the mitochondria and the Golgi apparatus.
Abstract: Copper is an essential micronutrient that plays a central role for a broad range of biological processes. Although there is compelling evidence that the intracellular milieu does not contain any free copper ions, the rapid kinetics of copper uptake and release suggests the presence of a labile intracellular copper pool. To elucidate the subcellular localization of this pool, we have synthesized and characterized a membrane-permeable, copper-selective fluorescent sensor (CTAP-1). Upon addition of Cu(I), the sensor exhibits a 4.6-fold emission enhancement and reaches a quantum yield of 14%. The sensor exhibits excellent selectivity toward Cu(I), and its emission response is not compromised by the presence of millimolar concentrations of Ca(II) or Mg(II) ions. Variable temperature dynamic NMR studies revealed a rapid Cu(I) self-exchange equilibrium with a low activation barrier of deltaG++ = 44 kJ.mol(-1) and k(obs) approximately 10(5) s(-1) at room temperature. Mouse fibroblast cells (3T3) incubated with the sensor produced a copper-dependent perinuclear staining pattern, which colocalizes with the subcellular locations of mitochondria and the Golgi apparatus. To evaluate and confirm the sensor's copper-selectivity, we determined the subcellular topography of copper by synchrotron-based x-ray fluorescence microscopy. Furthermore, microprobe x-ray absorption measurements at various subcellular locations showed a near-edge feature that is characteristic for low-coordinate monovalent copper but does not resemble the published spectra for metallothionein or glutathione. The presented data provide a coherent picture with strong evidence for a kinetically labile copper pool, which is predominantly localized in the mitochondria and the Golgi apparatus.
TL;DR: In this article, the photocatalysts with various copper species (Cu 0, Cu I, Cu II ) were prepared by an improved-impregnation method, where copper nitrate is doped into TiO 2 Degussa-P25.
TL;DR: In this article, a series of experiments were conducted in a batch system to assess the effect of the system variables, i.e. initial pH, temperature and initial metal ion concentration.
TL;DR: In this paper, the authors synthesized artifact-free bulk nanocrystalline copper samples with a narrow grain size distribution (mean grain size of 23nm) that exhibited tensile yield strength about 11 times higher than that of conventional coarse-grained copper, while retaining a 14% uniform tensile elongation.
Abstract: We have synthesized artifact-free bulk nanocrystalline copper samples with a narrow grain size distribution (mean grain size of 23nm) that exhibited tensile yield strength about 11 times higher than that of conventional coarse-grained copper, while retaining a 14% uniform tensile elongation. In situ dynamic straining transmission electron microscope observations of the nanocrystalline copper are also reported, which showed individual dislocation motion and dislocation pile-ups. This suggests a dislocation-controlled deformation mechanism that allows for the high strain hardening observed. Trapped dislocations are observed in the individual nanograins.
TL;DR: The contact angle hysteresis on these surfaces initially increased and then decreased as the contact angle increased, and the maximum occurred at a surface area where the equilibrium contact angle would suggest that a substantial proportion of the surface area was bridged.
Abstract: Rough and patterned copper surfaces were produced using etching and, separately, using electrodeposition. In both of these approaches the roughness can be varied in a controlled manner and, when hydrophobized, these surfaces show contact angles that increase with increasing roughness to above 160°. We show transitions from a Wenzel mode, whereby the liquid follows the contours of the copper surface, to a Cassie−Baxter mode, whereby the liquid bridges between features on the surface. Measured contact angles on etched samples could be modeled quantitatively to within a few degrees by the Wenzel and Cassie−Baxter equations. The contact angle hysteresis on these surfaces initially increased and then decreased as the contact angle increased. The maximum occurred at a surface area where the equilibrium contact angle would suggest that a substantial proportion of the surface area was bridged.
TL;DR: In this paper, a vertical aligned CuO nanorod arrays on copper electrodes with diameters of ∼5nm and lengths of hundreds of nanometers were synthesized successfully using a simple wet chemical method at room temperature.
TL;DR: In this paper, the effects of the intermetallic compound layer on the electrical and mechanical properties have been investigated under various annealing conditions, and two kinds of intermetallics layer were formed in the joints interface and identified by AlCu and Al 2 Cu.
TL;DR: In this paper, the copper adsorption by means of sawdust obtained as by-product from locally used wood was investigated and the results tend to explain the retention mechanism as an ion exchange process for binding the divalent metal ions to the sawdust.
TL;DR: The dye-sensitized solar cells (DSSC) were constructed using the copper complexes as redox couples to compare the photoelectrochemical responses with those using the conventional I(3)(-)/I(-) couple.
Abstract: The electron self-exchange rate constants of blue copper model complexes, [(-)-sparteine-N,N'](maleonitriledithiolato-S,S')copper ([Cu(SP)(mmt)])(0/)(-), bis(2,9-dimethy-1,10-phenanthroline)copper ([Cu(dmp)(2)](2+/+)), and bis(1,10-phenanthroline)copper ([Cu(phen)(2)](2+/+)) have been determined from the rate constants of electron transfer from a homologous series of ferrocene derivatives to the copper(II) complexes in light of the Marcus theory of electron transfer. The resulting electron self-exchange rate constant increases in the order: [Cu(phen)(2)](2+/+) < [Cu(SP)(mmt)](0/)(-) < [Cu(dmp)(2)](2+/+), in agreement with the order of the smaller structural change between the copper(II) and copper(I) complexes due to the distorted tetragonal geometry. The dye-sensitized solar cells (DSSC) were constructed using the copper complexes as redox couples to compare the photoelectrochemical responses with those using the conventional I(3)(-)/I(-) couple. The light energy conversion efficiency (eta) values under illumination of simulated solar light irradiation (100 mW/cm(2)) of DSSCs using [Cu(phen)(2)](2+/+), [Cu(dmp)(2)](2+/+), and [Cu(SP)(mmt)](0/)(-) were recorded as 0.1%, 1.4%, and 1.3%, respectively. The maximum eta value (2.2%) was obtained for a DSSC using the [Cu(dmp)(2)](2+/+) redox couple under the light irradiation of 20 mW/cm(2) intensity, where a higher open-circuit voltage of the cell was attained as compared to that of the conventional I(3)(-)/I(-) couple.
TL;DR: It was indicated that the adsorption of copper(II) ions onto C. annuum seeds could be described by the pseudo-second-order kinetic model and also followed the intraparticle diffusion model up to 60 min, but diffusion is not only the rate controlling step.
TL;DR: Thermal analysis showed that there was a significant increase in the PGF glass transition temperature as the CuO content increased, and the number of viable staphylococci both attached to theCuO-containing fibres and in the surrounding environment decreased.
TL;DR: It was shown that copper induced an oxidative stress in fish liver before significant metal accumulation in the liver could be detected, suggesting the involvement of differential mechanisms in copper uptake and metabolism.
TL;DR: Printed circuit boards, which are used in personal computers, were studied in order to recover the metals in the circuit boards through mechanical processing, such as crushing, screening, as well as magnetic and electrostatic separation, to demonstrate the feasibility of using these processes to separate metal fractions from polymers and ceramics.
TL;DR: In this article, the removal of chromium (III), copper (II) and zinc(II) from aqueous solution by adsorption on carrot residues (CR) was studied.
TL;DR: In this paper, electron microscope cathodoluminescence imaging is used to map successive generations of fluid inclusions in texturally complex quartz veinlets representing the main stage of ore metal introduction into the porphyry Cu-Au-Mo deposit at Bingham, Utah.
TL;DR: In this paper, the authors investigated thermal conductivity, diffusivity, effusivity and specific heat of polypropylene matrix filled with copper particles of two different sizes and found that the highest heat transport ability was observed for the composites filled with the smaller particles.
Abstract: Thermal conductivity, diffusivity, effusivity and specific heat of polypropylene matrix filled with copper particles of two different sizes were investigated. A parallel study of the evolution of the electrical conductivity was also carried out. The highest heat transport ability was observed for the composites filled with the smaller particles. Electrical conductivity investigations showed that the size of fillers also influences the percolation threshold. The Agari's model provides a good estimation of the thermal conductivity of composites for all filler concentrations. It was used in order to give a comparative analysis of both electrical and thermal properties of such two-phase systems. Nevertheless, the physical meaning of the two fitting parameters C1 and C2 of Agari's model has to be completed.
TL;DR: In this article, air-stable copper nanoclusters are used as catalysts in the Cu(I)-catalysed cycloaddition of azides with terminal alkynes to give 1,4-disubstituted 1,2,3-triazoles.
Abstract: Air-stable copper nanoclusters are good catalysts in the Cu(I)-catalysed “click” cycloaddition of azides with terminal alkynes to give 1,4-disubstituted 1,2,3-triazoles. No additional base or reducing agent is required. The reaction kinetics using various copper catalyst types and the function of copper particles in this system are studied and discussed.