These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Precursors for formation of copper selenide, indium selenide, copper indium diselenide, and/or copper indium gallium diselenide films  

DOEpatents

Liquid-based precursors for formation of Copper Selenide, Indium Selenide, Copper Indium Diselenide, and/or copper Indium Galium Diselenide include copper-organoselenides, particulate copper selenide suspensions, copper selenide ethylene diamine in liquid solvent, nanoparticulate indium selenide suspensions, and indium selenide ethylene diamine coordination compounds in solvent. These liquid-based precursors can be deposited in liquid form onto substrates and treated by rapid thermal processing to form crystalline copper selenide and indium selenide films.

Curtis, Calvin J; Miedaner, Alexander; Van Hest, Maikel; Ginley, David S

2014-11-04

2

Oxidation Mechanism of Copper Selenide  

NASA Astrophysics Data System (ADS)

The oxidation mechanism of copper selenide was investigated at deselenization temperatures of copper refining anode slimes. The isothermal roasting of synthetic, massive copper selenide in flowing oxygen and oxygen - 20% sulfur dioxide mixtures at 450-550 °C indicate that in both atmospheres the mass of Cu2Se increases as a function of time, due to formation of copper selenite as an intermediate product. Copper selenide oxidises to copper oxides without formation of thick copper selenite scales, and a significant fraction of selenium is vaporized as SeO2(g). The oxidation product scales on Cu2Se are porous which allows transport of atmospheric oxygen to the reaction zone and selenium dioxide vapor to the surrounding gas. Predominance area diagrams of the copper-selenium system, constructed for selenium roasting conditions, indicate that the stable phase of copper in a selenium roaster gas with SO2 is the sulfate CuSO4. The cuprous oxide formed in decomposition of Cu2Se is further sulfated to CuSO4.

Taskinen, Pekka; Patana, Sonja; Kobylin, Petri; Latostenmaa, Petri

2014-09-01

3

Aqueous preparation of surfactant-free copper selenide nanowires.  

PubMed

Uniform surfactant-free copper selenide (Cu2-xSe) nanowires were prepared via an aqueous route. The effects of reaction parameters such as Cu/Se precursor ratio, Se/NaOH ratio, and reaction time on the formation of nanowires were comprehensively investigated. The results show that Cu2-xSe nanowires were formed through the assembling of CuSe nanoplates, accompanied by their self-redox reactions. The resultant Cu2-xSe nanowires were explored as a potential thermoelectric candidate in comparison with commercial copper selenide powder. Both synthetic and commercial samples have a similar performance and their figures of merit are 0.29 and 0.38 at 750K, respectively. PMID:25527088

Chen, Xinqi; Li, Zhen; Yang, Jianping; Sun, Qiao; Dou, Shixue

2015-03-15

4

Photoconductivity in reactively evaporated copper indium selenide thin films  

NASA Astrophysics Data System (ADS)

Copper indium selenide thin films of composition CuInSe2 with thickness of the order of 130 nm are deposited on glass substrate at a temperature of 423 ±5 K and pressure of 10-5 mbar using reactive evaporation, a variant of Gunther's three temperature method with high purity Copper (99.999%), Indium (99.999%) and Selenium (99.99%) as the elemental starting materials. X-ray diffraction (XRD) studies shows that the films are polycrystalline in nature having preferred orientation of grains along the (112) plane. The structural type of the film is found to be tetragonal with particle size of the order of 32 nm. The structural parameters such as lattice constant, particle size, dislocation density, number of crystallites per unit area and strain in the film are also evaluated. The surface morphology of CuInSe2 films are studied using 2D and 3D atomic force microscopy to estimate the grain size and surface roughness respectively. Analysis of the absorption spectrum of the film recorded using UV-Vis-NIR Spectrophotometer in the wavelength range from 2500 nm to cutoff revealed that the film possess a direct allowed transition with a band gap of 1.05 eV and a high value of absorption coefficient (?) of 106 cm-1 at 570 nm. Photoconductivity at room temperature is measured after illuminating the film with an FSH lamp (82 V, 300 W). Optical absorption studies in conjunction with the good photoconductivity of the prepared p-type CuInSe2 thin films indicate its suitability in photovoltaic applications.

Urmila, K. S.; Asokan, T. Namitha; Pradeep, B.; Jacob, Rajani; Philip, Rachel Reena

2014-01-01

5

Photoconductivity in reactively evaporated copper indium selenide thin films  

SciTech Connect

Copper indium selenide thin films of composition CuInSe{sub 2} with thickness of the order of 130 nm are deposited on glass substrate at a temperature of 423 ±5 K and pressure of 10{sup ?5} mbar using reactive evaporation, a variant of Gunther's three temperature method with high purity Copper (99.999%), Indium (99.999%) and Selenium (99.99%) as the elemental starting materials. X-ray diffraction (XRD) studies shows that the films are polycrystalline in nature having preferred orientation of grains along the (112) plane. The structural type of the film is found to be tetragonal with particle size of the order of 32 nm. The structural parameters such as lattice constant, particle size, dislocation density, number of crystallites per unit area and strain in the film are also evaluated. The surface morphology of CuInSe{sub 2} films are studied using 2D and 3D atomic force microscopy to estimate the grain size and surface roughness respectively. Analysis of the absorption spectrum of the film recorded using UV-Vis-NIR Spectrophotometer in the wavelength range from 2500 nm to cutoff revealed that the film possess a direct allowed transition with a band gap of 1.05 eV and a high value of absorption coefficient (?) of 10{sup 6} cm{sup ?1} at 570 nm. Photoconductivity at room temperature is measured after illuminating the film with an FSH lamp (82 V, 300 W). Optical absorption studies in conjunction with the good photoconductivity of the prepared p-type CuInSe{sub 2} thin films indicate its suitability in photovoltaic applications.

Urmila, K. S., E-mail: urmilaks7@gmail.com; Asokan, T. Namitha, E-mail: urmilaks7@gmail.com; Pradeep, B., E-mail: urmilaks7@gmail.com [Solid State Physics Laboratory, Cochin University of Science and Technology, Kochi, Kerala (India); Jacob, Rajani; Philip, Rachel Reena [Thin Film Research Laboratory, Union Christian College, Aluva, Kerala (India)

2014-01-28

6

Band structure and transport studies of copper selenide: An efficient thermoelectric material  

NASA Astrophysics Data System (ADS)

We report the band structure calculations for high temperature cubic phase of copper selenide (Cu2Se) employing Hartree-Fock approximation using density functional theory within the generalized gradient approximation. These calculations were further extended to theoretically estimate the electrical transport coefficients of Cu2Se employing Boltzmann transport theory, which show a reasonable agreement with the corresponding experimentally measured values. The calculated transport coefficients are discussed in terms of the thermoelectric (TE) performance of this material, which suggests that Cu2Se can be a potential p-type TE material with an optimum TE performance at a carrier concentration of ˜ 4 - 6 × 10 21 cm - 3 .

Tyagi, Kriti; Gahtori, Bhasker; Bathula, Sivaiah; Auluck, S.; Dhar, Ajay

2014-10-01

7

Colloidally stable selenium@copper selenide core@shell nanoparticles as selenium source for manufacturing of copper-indium-selenide solar cells.  

PubMed

Selenium nanoparticles with diameters of 100-400nm are prepared via hydrazine-driven reduction of selenious acid. The as-prepared amorphous, red selenium (a-Se) particles were neither a stable phase nor were they colloidally stable. Due to phase transition to crystalline (trigonal), grey selenium (t-Se) at or even below room temperature, the particles merged rapidly and recrystallized as micronsized crystal needles. As a consequence, such Se particles were not suited for layer deposition and as a precursor to manufacture thin-film CIS (copper indium selenide/CuInSe2) solar cells. To overcome this restriction, Se@CuSe core@shell particles are presented here. For these Se@CuSe core@shell nanoparticles, the phase transition a-Se?t-Se is shifted to temperatures higher than 100°C. Moreover, a spherical shape of the particles is retained even after phase transition. Composition and structure of the Se@CuSe core@shell nanostructure are evidenced by electron microscopy (SEM/STEM), DLS, XRD, FT-IR and line-scan EDXS. As a conceptual study, the newly formed Se@CuSe core@shell nanostructures with CuSe acting as a protecting layer to increase the phase-transition temperature and to improve the colloidal stability were used as a selenium precursor for manufacturing of thin-film CIS solar cells and already lead to conversion efficiencies up to 3%. PMID:24267336

Dong, Hailong; Quintilla, Aina; Cemernjak, Marco; Popescu, Radian; Gerthsen, Dagmar; Ahlswede, Erik; Feldmann, Claus

2014-02-01

8

Hydrothermal synthesis of copper selenides with controllable phases and morphologies from an ionic liquid precursor  

NASA Astrophysics Data System (ADS)

Cu2-xSe nanocrystals and CuSe nanoflakes are successfully synthesized through a convenient hydrothermal method from an ionic liquid precursor 1-n-butyl-3-ethylimidazolium methylselenite ([BMIm][SeO2(OCH3)]). The phases and morphologies of the copper selenides can be controlled by simply changing the atom ratio of Cu/Se in the reactants and reaction temperature. Furthermore, it is found that the [BMIm][SeO2(OCH3)] not only serves as Se source but also has influence on the shapes of CuSe nanoflakes. The adsorption of alkyl imidazolium rings ([BMIm]+) onto the (0001) facets of covellite CuSe prohibits the growth in the [0001] direction, and CuSe nuclei growth mainly processes along the six symmetric directions (+/-[01&cmb.macr;11], +/-[101&cmb.macr;1&cmb.macr;], and +/-[1&cmb.macr;100]) to form flakelike CuSe. The obtained copper selenides are characterized by XRD, SEM, EDS, XPS, TEM, and HRTEM. The results indicate that the Cu2-xSe nanocrystals are nearly spherical particles with an average diameter of about 20 nm, the hexagonal CuSe nanoflakes are single crystals with an edge length of 100-400 nm and a thickness of 25-50 nm. The potential formation mechanism of the copper selenides is also proposed.Cu2-xSe nanocrystals and CuSe nanoflakes are successfully synthesized through a convenient hydrothermal method from an ionic liquid precursor 1-n-butyl-3-ethylimidazolium methylselenite ([BMIm][SeO2(OCH3)]). The phases and morphologies of the copper selenides can be controlled by simply changing the atom ratio of Cu/Se in the reactants and reaction temperature. Furthermore, it is found that the [BMIm][SeO2(OCH3)] not only serves as Se source but also has influence on the shapes of CuSe nanoflakes. The adsorption of alkyl imidazolium rings ([BMIm]+) onto the (0001) facets of covellite CuSe prohibits the growth in the [0001] direction, and CuSe nuclei growth mainly processes along the six symmetric directions (+/-[01&cmb.macr;11], +/-[101&cmb.macr;1&cmb.macr;], and +/-[1&cmb.macr;100]) to form flakelike CuSe. The obtained copper selenides are characterized by XRD, SEM, EDS, XPS, TEM, and HRTEM. The results indicate that the Cu2-xSe nanocrystals are nearly spherical particles with an average diameter of about 20 nm, the hexagonal CuSe nanoflakes are single crystals with an edge length of 100-400 nm and a thickness of 25-50 nm. The potential formation mechanism of the copper selenides is also proposed. Electronic supplementary information (ESI) available: Fig. S1: 1-n-butyl-3-methylimidazolium methylselenite ([BMIm][SeO2(OCH3)]. Fig. S2: XRD pattern of Se from [BMIm][SeO2(OCH3)]. Fig. S3: Survey XPS spectra of (a) Cu2-xSe and (b) CuSe. Fig. S4: Schematic illustration of the chemical bonds in [BMIm][SeOB2B(OCHB3B)]. Fig. S5: (a) XRD pattern and (b) SEM image of CuB2-xBSe from the NaB2BSeOB3B precursor without using [BMIm]Br, (c) SEM image of CuB2-xBSe from the NaB2BSeOB3B precursor and equal mole amount of [BMIm]Br (XRD pattern is not listed). Fig. S6: (a) SEM image of sample 2 synthesized under the mole ratio of Cu/Se = 1 and reaction temperature 150 °C (b) XRD pattern of sample 1 synthesized under the mole ratio of Cu/Se = 2 and reaction temperature 120 °C (c) XRD patterns of samples synthesized under the mole ratio of Cu/Se = 2 and reaction temperature 150 °C (sample 1, a) and 120 °C (sample 4, b); (d) XRD pattern of sample 6 synthesized under the mole ratio of Cu/Se = 1 : 2 and reaction temperature 180 °C (e) SEM pattern of sample 6, inset (a) is the magnified SEM image of a Cu2-xSe microcrystal, inset (b) is the corresponding cogeometrical structure of Cu2-xSe microcrystal; (f) SEM image of sample 7 synthesized under the mole ratio of Cu/Se = 2 : 1 and reaction temperature 180 °C. Fig. S7: SEM images of sample 6 synthesized at 180 °C for different reaction times of (a) 4 h, (b) 8 h. See DOI: 10.1039/c1nr10833f

Liu, Xiaodi; Duan, Xiaochuan; Peng, Peng; Zheng, Wenjun

2011-12-01

9

The optical and electrical properties of copper indium di-selenide thin films  

NASA Astrophysics Data System (ADS)

Thin films of copper indium di-selenide (CIS) with a wide range of compositions near stoichiometry have been formed on glass substrates in vacuum by the stacked elemental layer (SEL) deposition technique. The compositional and optical properties of the films have been measured by proton-induced X-ray emission (PIXE) and spectrophotometry (photon wavelength range of 300-2500 nm), respectively. Electrical conductivity ( ?), charge-carrier concentration ( n), and Hall mobility ( ?H) were measured at temperatures ranging from 143 to 400 K. It was found that more indium-rich films have higher energy gaps than less indium-rich ones while more Cu-rich films have lower energy gaps than less Cu-rich films. The sub-bandgap absorption of photons is minimum in the samples having Cu/In ? 1 and it again decreases, as Cu/In ratio becomes less than 0.60. Indium-rich films show n-type conductivities while near-stoichiometric and copper-rich films have p-type conductivities. At 300 K ?, n and ?H of the films vary from 2.15 × 10 -3 to 1.60 × 10 -1 (? cm) -1, 2.28 × 10 15 to 5.74 × 10 17 cm -3 and 1.74 to 5.88 cm 2 (V s) -1, respectively, and are dependent on the composition of the films. All the films were found to be non-degenerate. The ionization energies for acceptors and donors vary between 12 and 24, and 3 and 8 meV, respectively, and they are correlated well with the Cu/In ratios. The crystallites of the films were found to be partially depleted in charge carriers.

Firoz Hasan, S. M.; Subhan, M. A.; Mannan, Kh. M.

2000-08-01

10

Neutralization by Metal Ions of the Toxicity of Sodium Selenide  

PubMed Central

Inert metal-selenide colloids are found in animals. They are believed to afford cross-protection against the toxicities of both metals and selenocompounds. Here, the toxicities of metal salt and sodium selenide mixtures were systematically studied using the death rate of Saccharomyces cerevisiae cells as an indicator. In parallel, the abilities of these mixtures to produce colloids were assessed. Studied metal cations could be classified in three groups: (i) metal ions that protect cells against selenium toxicity and form insoluble colloids with selenide (Ag+, Cd2+, Cu2+, Hg2+, Pb2+ and Zn2+), (ii) metal ions which protect cells by producing insoluble metal-selenide complexes and by catalyzing hydrogen selenide oxidation in the presence of dioxygen (Co2+ and Ni2+) and, finally, (iii) metal ions which do not afford protection and do not interact (Ca2+, Mg2+, Mn2+) or weakly interact (Fe2+) with selenide under the assayed conditions. When occurring, the insoluble complexes formed from divalent metal ions and selenide contained equimolar amounts of metal and selenium atoms. With the monovalent silver ion, the complex contained two silver atoms per selenium atom. Next, because selenides are compounds prone to oxidation, the stabilities of the above colloids were evaluated under oxidizing conditions. 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB), the reduction of which can be optically followed, was used to promote selenide oxidation. Complexes with cadmium, copper, lead, mercury or silver resisted dissolution by DTNB treatment over several hours. With nickel and cobalt, partial oxidation by DTNB occurred. On the other hand, when starting from ZnSe or FeSe complexes, full decompositions were obtained within a few tens of minutes. The above properties possibly explain why ZnSe and FeSe nanoparticles were not detected in animals exposed to selenocompounds. PMID:23342137

Dauplais, Marc; Lazard, Myriam; Blanquet, Sylvain; Plateau, Pierre

2013-01-01

11

Magnetometer uses bismuth-selenide  

NASA Technical Reports Server (NTRS)

Characteristics of bismuth-selenide magnetometer are described. Advantages of bismuth-selenide magnetometer over standard magnetometers are stressed. Thermal stability of bismuth-selenide magnetometer is analyzed. Linearity of output versus magnetic field over wide range of temperatures is reported.

Woollman, J. A.; Spain, I. L.; Beale, H.

1972-01-01

12

Improving the efficiency of copper indium gallium (Di-)selenide (CIGS) solar cells through integration of a moth-eye textured resist with a refractive index similar to aluminum doped zinc oxide  

NASA Astrophysics Data System (ADS)

Textured transparent conductors are widely used in thin-film silicon solar cells. They lower the reflectivity at interfaces between different layers in the cell and/or cause an increase in the path length of photons in the Si absorber layer, which both result in an increase in the number of absorbed photons and, consequently, an increase in short-circuit current density (Jsc) and cell efficiency. Through optical simulations, we recently obtained strong indications that texturing of the transparent conductor in copper indium gallium (di-)selenide (CIGS) solar cells is also optically advantageous. Here, we experimentally demonstrate that the Jsc and efficiency of CIGS solar cells with an absorber layer thickness (dCIGS) of 0.85 ?m, 1.00 ?m and 2.00 ?m increase through application of a moth-eye textured resist with a refractive index that is sufficiently similar to AZO (nresist = 1.792 vs. nAZO = 1.913 at 633 nm) to avoid large optical losses at the resist-AZO interface. On average, Jsc increases by 7.2%, which matches the average reduction in reflection of 7.0%. The average relative increase in efficiency is slightly lower (6.0%). No trend towards a larger relative increase in Jsc with decreasing dCIGS was observed. Ergo, the increase in Jsc can be fully explained by the reduction in reflection, and we did not observe any increase in Jsc based on an increased photon path length.

Burghoorn, M.; Kniknie, B.; van Deelen, J.; Xu, M.; Vroon, Z.; van Ee, R.; van de Belt, R.; Buskens, P.

2014-12-01

13

Absorption coefficient of zinc selenide grown from the melt  

SciTech Connect

The authors study the absorption coefficient in a series of non-transparent set-ups, which closely resemble the schematic diagram presented. The measurement cells were in air. Temperature was measured by thermocouple sensors, whose contacts with the zinc selenide crystals were screened from the light scattered from the volume of the sample. A continuous CO laser was used as the light source. The absorption coefficient (beta) of zinc selenide single crystals grown from the melt increases with contamination by metallic impurities, among which copper appears to have the greatest effect on beta. The magnitude of absorption coefficient is, generally, not related to the measured transmission and must be determined independently.

Kulakov, M.P.; Fadeev, A.V.; Ivanenko, S.G.; Khasanov, I.S.; Ryazanova, N.D.

1986-02-01

14

Selenide retention by mackinawite.  

PubMed

The isotope (79)Se may be of great concern with regard to the safe disposal of nuclear wastes in deep geological repositories due to its long half-life and potential mobility in the geosphere. The Se mobility is controlled by the oxidation state: the oxidized species (Se(IV)) and (Se(VI)) are highly mobile, whereas the reduced species (Se(0) and Se(-II)) form low soluble solids. The mobility of this trace pollutant can be greatly reduced by interacting with the various barriers of the repository. Numerous studies report on the oxidized species retention by mineral phases, but only very scarce studies report on the selenide (Se(-II)) retention. In the present study, the selenide retention by coprecipitation with and by adsorption on mackinawite (FeS) was investigated. XRD and SEM analyses of the samples reveal no significant influence of Se on the mackinawite precipitate morphology and structure. Samples from coprecipitation and from adsorption are characterized at the molecular scale by a multi-edge X-ray absorption spectroscopy (XAS) investigation. In the coprecipitation experiment, all elements (S, Fe, and Se) are in a low ionic oxidation state and the EXAFS data strongly point to selenium located in a mackinawite-like sulfide environment. By contacting selenide ions with FeS in suspension, part of Se is located in an environment similar to that found in the coprecipitation experiment. The explanation is a dynamical dissolution-recrystallization mechanism of the highly reactive mackinawite. This is the first experimental study to report on selenide incorporation in iron monosulfide by a multi-edge XAS approach. PMID:22900520

Finck, N; Dardenne, K; Bosbach, D; Geckeis, H

2012-09-18

15

Molecular Structure of Hydrogen Selenide  

NSDL National Science Digital Library

Hydrogen Selenide is a colorless toxic gas with a foul penetrating odor that it is extremely flammable and can form explosive mixture with air. It is used for the preparation of metallic selenides and organoselenium compounds. It is also used as a dopant gas for preparation of semiconductor materials for use in lasers, solar cells and other equipment containing controlled amounts of significant impurities.

2003-06-04

16

COPPER(1-Y)SILVER(Y)INDIUM - DISULFIDE(1-X)SELENIDE(2X) as a Prototype of the Pentenary Chalcopyrite Semiconductor Systems.  

NASA Astrophysics Data System (ADS)

The group III-V mixed alloy quarternary semiconductors, such as Ga(,(1-y))In(,y)As(,(1-x))P(,x) have been extensively employed in lattice matching different semiconducting layers (at specific bandgaps) to form heterojunction electro-optical devices. However, these cover only a limited set of direct bandgap/lattice constant combinations. The analogous pentenary alloys, consisting of the ternary chalcopyrite groups I -III-VI(,2) and II-IV-V(,2), have the potential of similar applications as they cover an even wider band/lattice range. As a prototype of such alloys, samples of the pentenary Cu(,(1 -y))Ag(,y)InS(,2(1-x))Se(,2x) have been synthesized and studied. Samples were prepared by reacting stoichimetric powder mixtures at about 900 C. X-ray diffractometry tests suggest the compounds maintained complete powder solid solubility throughout the system in the chalcopyrite crystal structure. The intrinsic conductivity type of the alloys appear to follow a trend towards n-type for silver and sulfur rich compounds, while forming p-type for copper and selenium rich materials. The bandgap of these samples were measured using cathodoluminescence techniques, which generally have some ambiguity in their resulting estimates. To generate better values of the band parameters extensive computer modeling for the emission spectra from heavily doped direct bandgap materials was done. The effect of band tails and Gaussian impurity states on the luminescence spectra was studied for changes in doping densities, temperature and carrier injection levels. Formulae were derived from these models to obtain better estimates of the bandgap and impurity activation levels. Algorithms were developed to obtain the impurity spreading energy of a tailed or Gaussian band, and the quasi-Fermi energy levels for injected current in a material with a specific band structure. Cathodoluminescence measurements were made at 300 and 77 K on the samples. As predicted by the models, it was found easier to generate good estimates from the 300 K results due to the obscuring effects of the impurity bands at cooler temperatures. Using these band estimates least squares fits were made on the data to generate the topological bandgap/lattice constant versus compositional value maps for the studied alloy.

Chapman, Glenn Harrison

17

Advanced selenide thermoelectric development program. Final report  

SciTech Connect

The primary objective of this work was to demonstrate that copper silver selenide and TAGS could be segmented. The hot junction temperature was planned to be 725/sup 0/C with the segmentation temperature at 400/sup 0/C, both temperatures were selected to prevent excessive sublimation from the hot ends of the segments, respectively. The program was planned as a cooperative effort between General Atomic company and Teledyne Energy Systems. Accordingly, General Atomic synthesized the CuAgSe that was used to fabricate the test hardware that was ultimately delivered to General Atomic for testing. Both the CuAgSe and TAGS were hot pressed in an argon atmosphere then the segments were furnace-bonded to each other. A secondary objective was to produce CuAgSe powder by rapid solidification.

Seetoo, W.R.

1981-07-20

18

Copper  

MedlinePLUS

... minimum recommended dietary allowance (RDA) for copper is 0.9 milligrams per day for most adults, 1 ... in the cancer process is still unclear, copper complexes have been shown to ... evidence that trace metals, including copper, iron and zinc, may have a ...

19

Copper.  

PubMed

Copper is an essential trace element, which is an important catalyst for heme synthesis and iron absorption. Following zinc and iron, copper is the third most abundant trace element in the body. Copper is a noble metal, like silver and gold. Useful industrial properties include high thermal and electrical conductivity, low corrosion, alloying ability, and malleability. Most of the metallic copper appears in electrical applications. Copper is a constituent of intrauterine contraceptive devices and the release of copper is necessary for their contraceptive effects. The average daily intake of copper in the US is about 1 mg Cu with the primary source being the diet. The bioavailability of copper from the diet is about 65-70% depending on a variety of factors including chemical form, interaction with other metals, and dietary components. The biological half-life of copper from the diet is 13-33 days with bilary excretion being the major route of elimination. Copper sulfate is a gastric irritant that produces erosion of the lining of the gastrointestinal tract. Chronic copper toxicity is rare and primarily affects the liver. Wilson's disease and Indian childhood cirrhosis are examples of severe chronic liver disease that results from the genetic predisposition to the hepatic accumulation of copper. The serum copper concentration ranges up to approximately 1.5 mg/L in healthy persons. Gastrointestinal symptoms occur at whole blood concentrations near 3 mg Cu/L. Chelating agents (CaNa2EDTA, BAL) are recommended in severe poisoning, but there are little pharmacokinetic data to evaluate the effectiveness of these agents. PMID:10382557

Barceloux, D G

1999-01-01

20

Low-Resistivity Zinc Selenide for Heterojunctions  

NASA Technical Reports Server (NTRS)

Magnetron reactive sputtering enables doping of this semiconductor. Proposed method of reactive sputtering combined with doping shows potential for yielding low-resistivity zinc selenide films. Zinc selenide attractive material for forming heterojunctions with other semiconductor compounds as zinc phosphide, cadmium telluride, and gallium arsenide. Semiconductor junctions promising for future optoelectronic devices, including solar cells and electroluminescent displays. Resistivities of zinc selenide layers deposited by evaporation or chemical vapor deposition too high to form practical heterojunctions.

Stirn, R. J.

1986-01-01

21

Crystal chemistry and solid lubricating properties of the monochalcogenides gallium selenide and tin selenide  

NASA Astrophysics Data System (ADS)

The interatomic array and bond structure in crystalline states of the monochalcogenides tin selenide and gallium selenide are described and correlated with their solid lubricating capacity. Friction tests assessing their solid lubricating performance were carried out on pin-on-disk machine. Specifically, large crystalline pieces of each inorganic solid were cut and cleaved into flat squares and subsequently rubbed against sapphire balls. In another case, fine powders of gallium selenide and tin selenide and tin selenide were manually fed into the sliding interfaces of 440C pins and 440C disks. For the specific test conditions explored, friction coefficients of the sapphirel gallium selenide and sapphire/tin selenide pairs were approximately 0.23 and approximately 0.35, respectively. The friction coefficients of 440C pin/440C disk test pairs with gallium selenide and tin selenide powders were approximately 0.22 and approximately 0.38, respectively. For comparison, a number of parallel friction tests were also performed with MoS2 powders and compacts, and the results of these tests are reported. The friction data, together with the crystal-chemical knowledge and electron microscopy evidence, supported the conclusion that the solid lubricating capabilities and lubrication mechanisms of these solids are closely related to their crystal chemistry and the nature of their interlayer bonding.

Erdemir, Ali

1994-07-01

22

Electron transport in lead selenide nanocrystal arrays  

E-print Network

I have investigated electrical properties of arrays of lead selenide (PbSe) nanocrystals (NC's) of approximately 6nm diameter. The films become substantially more conducting when annealed at 400K, although no chemical ...

Schriver, Maria C

2005-01-01

23

Crystal chemistry and self-lubricating properties of monochalcogenides gallium selenide and tin selenide  

SciTech Connect

This paper describes the fundamentals of the crystal chemistry and self-lubricating mechanisms of two monochalcogenides; tin selenide and gallium selenide. Specifically, it enumerates their inter-atomic array and bond structure in crystalline states, and correlates this fundamental knowledge with their self-lubricating capacity. Friction tests assessing the self-lubricating performance of gallium and tin selenides were carried out on a pin-on-disk machine. Specifically, large crystalline pieces of gallium selenide and tin selenide were cut and cleaved into flat squares and subsequently rubbed against the sapphire balls. In another case, the fine powders (particle size {approx} 50--100 {mu}m) of gallium selenide and tin selenide were manually fed into the sliding interfaces of 440C pins and 440C disks. For the specific test conditions explored, it was found that the friction coefficients of the sapphire/gallium selenide and sapphire/tin selenide pairs were {approx} 0.23 and {approx} 0.35, respectively. The friction coefficients of 440C pin/440C disk test pairs with gallium selenide and tin selenide powders were on the orders of {approx} 0.22 and {approx} 0.38, respectively. For comparison, a number of parallel friction tests were performed with MoS{sub 2} powders and compacts and the results of these tests were also reported. The friction data together with the crystal-chemical knowledge and the electron microscopic evidence supported the conclusion that the lubricity and self-lubricating mechanisms of these solids are closely related to their crystal chemistry and the nature of interlayer bonding.

Erdemir, A.

1993-02-01

24

Isotopic analysis of dimethyl selenide  

SciTech Connect

The separated isotopes of selenium may be used as stable precursors for the synthesis of radio-bromine isotopes for positron emitter tomographic diagnostics. As part of a project to find a suitable distillation method for separating selenium isotopes, the need arose to study the organo-metallic compound dimethyl selenide. The complexity of the mass spectrum tended to obscure the isotope effect with 35 major peaks being measured. A least-squares fitting procedure was developed for the 13 fragmentation factors as well as a few hundredths of a percent, yet no sizeable separation was observed across the test column. According to these measurements, the effect of one mass unit increase in the selenium isotope results in less than 10 ppM in the vapor pressure of the compound. 4 figures.

McInteer, B.B.

1984-01-01

25

Pressure-induced structural transformations in cadmium selenide nanorods  

E-print Network

Pressure-induced structural transformations in cadmium selenide nanorods Nicholas Jabari Lee, Rajiv in cadmium selenide CdSe nanorods are studied using parallel molecular dynamics. Nanorods 4.4 nm in diameter from four- fold wurtzite WZ to six-fold RS coordinated structures in Cadmium selenide CdSe , are also

Southern California, University of

26

Selenide technology evaluation program at JPL  

NASA Technical Reports Server (NTRS)

Results are presented for experimental and analytical investigations of the overall performance of a selenide radioisotope thermoelectric generator intended to provide the electrical power for interplanetary spaceprobes such as the Galileo mission to Jupiter. The discussion focuses on technology areas of concern, electrical properties of the selenide thermoelectric materials used, and thermal conductivity of these materials for superior performance. It is shown that the selenide thermoelectric materials offer the advantage of high conversion efficiency. The long-life requirement on the power system for the Galileo mission necessitates proper design, known fabrication techniques, and reproducible assembly techniques in order to ensure stability of the thermoelectric properties. However, the thermophysical properties - sublimation and creep - of the p-material remains an area of considerable concern.

Stapfer, G.; Garvey, L.

1978-01-01

27

Electrometallurgy of copper refinery anode slimes  

NASA Astrophysics Data System (ADS)

High-selenium copper refinery anode slimes form two separate and dynamically evolving series of compounds with increasing electrolysis time. In one, silver is progressively added to non-stoichiometric copper selenides, both those originally present in the anode and those formed subsequently in the slime layer, and in the other, silver-poor copper selenides undergo a dis-continuous crystallographic sequence of anodic-oxidative transformations. The silver-to-selenium molar ratio in the as-cast anode and the current density of electrorefining can be used to construct predominance diagrams for both series and, thus, to predict the final bulk “mineralogy” of the slimes. Although totally incorrect in detail, these bulk data are sufficiently accurate to provide explanations for several processing problems which have been experienced by Kidd Creek Division, Falconbridge Ltd., in its commercial tankhouse. They form the basis for a computer model which predicts final cathode quality from chemical analyses of smelter feed.

Scott, J. D.

1990-08-01

28

Indium selenides: structural characteristics, synthesis and their thermoelectric performances.  

PubMed

Indium selenides have attracted extensive attention in high-efficiency thermoelectrics for waste heat energy conversion due to their extraordinary and tunable electrical and thermal properties. This Review aims to provide a thorough summary of the structural characteristics (e.g. crystal structures, phase transformations, and structural vacancies) and synthetic methods (e.g. bulk materials, thin films, and nanostructures) of various indium selenides, and then summarize the recent progress on exploring indium selenides as high-efficiency thermoelectric materials. By highlighting challenges and opportunities in the end, this Review intends to shine some light on the possible approaches for thermoelectric performance enhancement of indium selenides, which should open up an opportunity for applying indium selenides in the next-generation thermoelectric devices. PMID:24729463

Han, Guang; Chen, Zhi-Gang; Drennan, John; Zou, Jin

2014-07-01

29

The electrochemical oxidation of organic selenides and selenoxides  

SciTech Connect

The electrochemical oxidation of alkyl and aryl selenides was investigated in acetonitrile. The oxidation of diphenyl selenide and di(4-methylphenyl) selenide led primarily to the formation of their respective selenoxides, which were identified by exhaustive coulometric oxidation and {sup 1}H and {sup 13}C analysis of the products. The selenoxide itself was not observed in the cyclic voltammetry of the selenide for two reasons: first, the protonation of the selenoxide by the acid formed from the reaction of water with the cation radical and second, the formation of a selenoxide hydrate. The formation of the hydrate with diphenyl selenoxide was verified by isolation of the dimethoxy derivative. In addition to the selenoxide, selenonium compounds, formed by the coupling of the oxidized material, were also observed. The alkyl selenides were generally oxidized at a lower potential than the aryl selenides. This trend is different from the sulfur analogues, where the aryl sulfides are easier to oxidize than their alkyl counterparts. As a result, the difference in their redox potentials is relatively small. These differences may occur because the oxidation of aryl sulfides is more likely to take place on the aromatic ring, which leads to a greater yield of the coupled products (about 100%) when compared to the selenide analogue.

Ryan, M.D.; Yau, J.; Hack, M. [Marquette Univ., Milwaukee, WI (United States). Dept. of Chemistry

1997-06-01

30

Chemical deposition of thin films of lead selenide  

E-print Network

in the reaction medium, and precoating the glass surface with a very light film of lead selenide. A, Colloidal Pretreatment Prior to mirroring, the slides were placed in colloidal solutiens of silver iodide (14)~ gold (15), and lead sulfide (16) for ten.... In this case the formation of silver selenide did improve the quality of the mirror. The greatest increase in the rate of deposition was obcained when the slides were precoated with colloidal lead selenide. The glass slide, prior to the final deposition...

Skovlin, Dean Oliver

2012-06-07

31

Growth of cadmium selenide layers by electrodeposition  

NASA Astrophysics Data System (ADS)

Cadmium selenide (CdSe) films have been electrodeposited from a bath containing CdSO4 and SeO2. The pH of the bath was around 2. The deposition was done by short circuiting different substrates like Indium Tin Oxide (ITO), molybdenum, sodium selenosulphite etc. to an easily oxidizable electrode (such as Al/Cd) in an electrolytic bath. The temperature of the deposition bath was varied in the range 60 to 85 C. The as-grown films were characterized by XRD and SEM. Electrical characterization of the ITO/-CdSe/In structure was made by studying the current-voltage characteristics. Optical absorption measurements yielded a direct band gap around 1.65 eV.

Murali, K. R.; Radhakrishna, I.; Nagaraja Rao, K.; Venkatesan, V. K.

1990-08-01

32

Ex situ formation of metal selenide quantum dots using bacterially derived selenide precursors  

NASA Astrophysics Data System (ADS)

Luminescent quantum dots were synthesized using bacterially derived selenide (SeII-) as the precursor. Biogenic SeII- was produced by the reduction of SeIV by Veillonella atypica and compared directly against borohydride-reduced SeIV for the production of glutathione-stabilized CdSe and ?-mercaptoethanol-stabilized ZnSe nanoparticles by aqueous synthesis. Biological SeII- formed smaller, narrower size distributed QDs under the same conditions. The growth kinetics of biologically sourced CdSe phases were slower. The proteins isolated from filter sterilized biogenic SeII- included a methylmalonyl-CoA decarboxylase previously characterized in the closely related Veillonella parvula. XAS analysis of the glutathione-capped CdSe at the S K-edge suggested that sulfur from the glutathione was structurally incorporated within the CdSe. A novel synchrotron based XAS technique was also developed to follow the nucleation of biological and inorganic selenide phases, and showed that biogenic SeII- is more stable and more resistant to beam-induced oxidative damage than its inorganic counterpart. The bacterial production of quantum dot precursors offers an alternative, ‘green’ synthesis technique that negates the requirement of expensive, toxic chemicals and suggests a possible link to the exploitation of selenium contaminated waste streams.

Fellowes, J. W.; Pattrick, R. A. D.; Lloyd, J. R.; Charnock, J. M.; Coker, V. S.; Mosselmans, J. F. W.; Weng, T.-C.; Pearce, C. I.

2013-04-01

33

Ex Situ Formation of Metal Selenide Quantum Dots Using Bacterially Derived Selenide Precursors  

SciTech Connect

Luminescent quantum dots were synthesized using bacterially derived selenide (SeII-) as the precursor. Biogenic SeII- was produced by the reduction of Se-IV by Veillonella atypica and compared directly against borohydride-reduced Se-IV for the production of glutathione-stabilized CdSe and beta-mercaptoethanol-stabilized ZnSe nanoparticles by aqueous synthesis. Biological SeII- formed smaller, narrower size distributed QDs under the same conditions. The growth kinetics of biologically sourced CdSe phases were slower. The proteins isolated from filter sterilized biogenic SeII- included a methylmalonyl-CoA decarboxylase previously characterized in the closely related Veillonella parvula. XAS analysis of the glutathione-capped CdSe at the S K-edge suggested that sulfur from the glutathione was structurally incorporated within the CdSe. A novel synchrotron based XAS technique was also developed to follow the nucleation of biological and inorganic selenide phases, and showed that biogenic SeII- is more stable and more resistant to beam-induced oxidative damage than its inorganic counterpart. The bacterial production of quantum dot precursors offers an alternative, 'green' synthesis technique that negates the requirement of expensive, toxic chemicals and suggests a possible link to the exploitation of selenium contaminated waste streams.

Fellowes, Jonathan W.; Pattrick, Richard; Lloyd, Jon; Charnock, John M.; Coker, Victoria S.; Mosselmans, JFW; Weng, Tsu-Chien; Pearce, Carolyn I.

2013-04-12

34

Preparation and Characterization of Silver Selenide Thin Film  

NASA Astrophysics Data System (ADS)

Silver selenide, a phase-changing chalcogenide material, is prepared using electro deposition method for various molarities. X-ray diffraction studies show the cubic lattice of the material. The micro-structural properties such as grain size, strain, dislocation density, and texture coefficient are examined. The lattice constant is calculated using Nelson-Relay function. Morphological studies are done and uniform distributions of grains are observed. High purities of thin films are confirmed by energy dispersive X-ray analysis. The band gap is calculated using UV-vis spectroscopy and photoluminescence technique, and hence, the Stokes's effect is observed in silver selenide thin films. It is the first time that the lattice constant and the Urbach energy for various molarities in the case of silver selenide thin films are reported.

Chandrasekar, L. Bruno; Vijayalakshmi, R.; Rajeswari, B.; Chandramohan, R.; Arivazhagan, G.; Packiaseeli, S. Arulmozhi

2014-09-01

35

Growth of zinc selenide crystals doped with magnesium  

SciTech Connect

The present work examines the growth conditions and several properties of zinc selenide crystals doped with magnesium selenide. Doped crystals of Zn /SUB 1-x/ Mg /SUB x/ Se solid solutions in the composition range O is less than or equal to x which is less than or equal to 0.21 were grown. The structural and optical properties of the crystals were studied. Crystals of the cubic phase can be grown up to x is less than 0.18 without residual stresses.

Kulakov, M.P.; Fadeev, A.V.

1986-08-01

36

Optical properties and electronic structures of copper indium gallium selenide: Effect of copper deficiency  

NASA Astrophysics Data System (ADS)

In this thesis, I describe basic research done to understand the optical properties and electronic structure of polycrystalline thin-film CuIn 1-xGaxSe 2 (CIGS) used for high efficiency photovoltaic (PV) solar cells. The effect of Cu deficiency on CIGS material properties has been intensively studied. The physics of p-n junctions and their application to photovoltaic solar cells are thoroughly discussed in Chap. 1. Chapter 2 presents a general knowledge of CIGS materials in terms of crystal structure, phase, electronic structure, intrinsic defects, and growth and characterization methods. Chapter 3 covers the physics of spectroscopic ellipsometry in detail, especially for Maxwell's equations, polarization of light waves, Fresnel equations, and the fundamental equation of ellipsometry. The method used to determine the optical constants from ellipsometric parameters is introduced using an easily understandable example, SiO2 on Si. Chapter 4 present the results of extensive studies of the effect of Cu deficiency on the properties of CuInSe2 (CIS). Phase transitions, optical properties and the electronic structure are discussed for Cu-poor CIS. Probing defect levels in the sub-bandgap region of CIS was successful using spectroscopic ellipsometry and the results are compared with first-principles calculations and data from the literature. In the next chapter, general behaviors of the optical properties of CuIn1-xGa xSe2 are introduced. Similar schemes are used to study the effect of Cu deficiency on CuIn0.8Ga0.2Se 2 and CuIn0.6Ga0.4Se2 as that on CIS. The effect of Cu deficiency on the optical bowing coefficients has been explained. The maximum efficiency of laboratory thin-film polycrystalline CIGS solar cells exceeds their single-crystal counterparts. This has been explained in terms of Cu deficiency in CIGS. Our studies of the effect of Cu deficiency have provided the first experimental evidence in support of this hypothesis. We find that there is a reduction in the absorption strength in the spectral range of 1-3 eV determined by spectroscopic ellipsometry. This reduction can be explained in terms of the removal of Cu 3d density of states near valence band maximum (VBM) for Cu-poor CIGS. The properties of a distinct surface layer on CIGS are determined using spectroscopic ellipsometry. We found that Cu is more deficient at surface than in the bulk region of the surface using spectroscopic ellipsometry. These results have important implications for the functioning of polycrystalline photovoltaic devices. The grain boundary (GB) region can be thought as interior surface and is expected to be more Cu deficient than the grain interior (GI) region. In addition, GBs tend to getter defects and impurities during the high-temperature processing used to produce thin-film PX-CIGS. Cu vacancies create a barrier for holes through the reduced DOS at the VBM. Because the GB tends to exclude majority carrier holes, it effectively impedes electron-hole recombination. The combination of gettering defects that cause fast non-radiative recombination with the carrier-separating effects of the GB band structure serve to greatly enhance the efficiency of thin-film PX-CIGS PV devices. Such a GB filter can be a key to the utilization of polycrystalline semiconductors in transport devices.

Han, Sung-Ho

37

Optical properties and electronic structures of copper indium gallium selenide: Effect of copper deficiency  

Microsoft Academic Search

In this thesis, I describe basic research done to understand the optical properties and electronic structure of polycrystalline thin-film CuIn 1-xGaxSe 2 (CIGS) used for high efficiency photovoltaic (PV) solar cells. The effect of Cu deficiency on CIGS material properties has been intensively studied. The physics of p-n junctions and their application to photovoltaic solar cells are thoroughly discussed in

Sung-Ho Han

2005-01-01

38

Composition change in zinc selenide crystals on zone melting  

SciTech Connect

Equations have been derived describing the composition change in the liquid on zone melting for nonstoichiometrically evaporating zinc selenide. These enable one to calculate the stoichiometry deviation in the crystals and to choose the working parameters to obtain crystals of a given composition. It is possible to make stoichiometric crystals only if there is excess zinc in the initial material.

Kolesnikov, N.N.; Fadeev, A.V.; Kulakov, M.P.

1986-08-01

39

G. J. Snyder Page 1 THERMOELECTRIC PROPERTIES OF SELENIDE SPINELS  

E-print Network

G. J. Snyder Page 1 THERMOELECTRIC PROPERTIES OF SELENIDE SPINELS G. Jeffrey Snyder*, T. Caillat, MS 277-207, Pasadena, CA 91109 *jeff.snyder@jpl.nasa.gov ABSTRACT Many compounds with the spinel experimental results presented here and to select promising thermoelectric spinels. Compounds studied here

40

Characterization of zinc selenide single crystals  

NASA Technical Reports Server (NTRS)

ZnSe single crystals of high quality and low impurity levels are desired for use as substrates in optoelectronic devices. This is especially true when the device requires the formation of homoepitaxial layers. While ZnSe is commercially available, it is at present extremely expensive due to the difficulty of growing single crystal boules with low impurity content and the resultant low yields. Many researchers have found it necessary to heat treat the crystals in liquid Zn in order to remove the impurities, lower the resistivity and activate the photoluminescence at room temperature. The physical vapor transport method (PVT) has been successfully used at MSFC to grow many single crystals of II-VI semiconducting materials including ZnSe. The main goal at NASA has been to try to establish the effect of gravity on the growth parameters. To this effect, crystals have been grown vertically upwards or horizontally. Both (111) and (110) oriented ZnSe crystals have been obtained via unseeded PVT growth. Preliminary characterization of the horizontally grown crystals has revealed that Cu is a major impurity and that the low temperature photoluminescence spectra is dominated by the copper peak. The ratio of the copper peak to the free exciton peak is being used to determine variations in composition throughout the crystal. It was the intent of this project to map the copper composition of various crystals via photoluminescence first, then measure their electrical resistivity and capacitance as a function of frequency before proceeding with a heat treatment designed to remove the copper impurities. However, equipment difficulties with the photoluminescence set up, having to establish a procedure for measuring the electrical properties of the as-grown crystals and time limitations made us re-evaluate the project goals. Vertically grown samples designated as ZnSe-25 were chosen to be measured electrically since they were not expected to show as much variation in their composition through their cross-section as the horizontally grown samples.

Gerhardt, Rosario A.

1996-01-01

41

Keeping Track of the Selenide zoo. A Combined Optical Microscopy - EPMA Study of Complex Selenides  

NASA Astrophysics Data System (ADS)

Hunting for new mineral phases is a fascinating scientific activity. This kind of research not only serves the replenishment of mineralogy textbooks with new mineral names but also the industry with new potential semiconductors, laser crystals and other 'high-tech phases'. Chemical analyses using the electron microprobe are an essential intermediate step in the course of the description of a new mineral. The study of a great number of different Cu-Pb-Ag-As-Hg-Tl-Sb-Bi-Cd selenides from the former uranium deposit Schlema-Alberode (Saxony) in the German part of the Erzgebirge represented a twofold challenge to us. The complex genetic and age relations of the ore minerals and gangue minerals entailed the development of very complex microstructures in a tight space. Typical features are symplectitic intergrowths, exsolutions, fine lamellae, zoned crystals and the development of pseudo- and paramorphs. Altogether we found 34 different selenide, sulfide and arsenide minerals, including 6 dimorpheous phases. Many of these minerals are indistinguishable by electron-optical methods used during different stages of the study. Dimorpheous minerals like bellidoite and berzelianite are as much indistinguishable like intergrowths of the minerals berzelianite, mgriite and lollingite using backscattered and secondary electron images. Optical microscopy is the key to overcome these problems. We show that the step-by-step combination of polarized light microscopy, phase contrast microscopy and differential interference contrast microscopy using transmitted and reflected light allowed a secure discrimination of the different minerals and unknown phases. 16 elements are incorporated into these phases either as main, minor or trace elements. A multitude of overlapping peaks, potenzial fluorescence effects caused by adjacent phases and different matrices in the minerals demanded the development of several specific methods optimized for the analysis of Pb-Se-, Cu-Tl-Se-, Cu-Fe-Zn-As-Se-, Hg-Pb-Ag-Se-, and arsenide phases. The electron microprobe studies will be followed by EBSD, TEM and crystal structure determination by X-ray diffraction using ultra-small amounts of material taken with the help of a New Wave micromill.

Schlothauer, T.; Renno, A. D.; Heide, G.

2007-12-01

42

Electron beam assisted synthesis of cadmium selenide nanomaterials  

SciTech Connect

Cadmium selenide nanomaterials of various shapes and sizes have been synthesized in different condensed media through electron beam irradiation using a 7 MeV linear accelerator. The microstructures in different media as well as the presence of capping reagents play a crucial role in the formation of nanomaterials of different shapes and sizes. Their optical properties could be efficiently tuned by controlling the synthetic parameters.

Rath, M. C.; Guleria, A.; Singh, S.; Singh, A. K.; Adhikari, S.; Sarkar, S. K. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

2013-02-05

43

Mono and digallium selenide clusters as potential superhalogens.  

PubMed

We present a systematic theoretical study on mono and digallium selenide clusters, Ga m Se n (m?=?1,?2 and n??=??1-4), along with their negatively and positively charged counterparts. Different theoretical methods, namely density functional theory (DFT), second-order Møller-Plesset perturbation theory (MP2) and coupled cluster singles and doubles, including non-iterative triples [CCSD(T)], were employed in conjunction with the 6-311+G(2df) basis set. The lowest-energy configurations of gallium selenides prefer to be planar, with the exception of cationic GaSe4 and Ga2Se4. The adiabatic electron affinities (AEA) of Ga m Se n (m?=?1,?2 and n??=?1-4) clusters range from 1.07 to 3.78 eV, and their adiabatic ionization potentials (AIP) vary from 7.57 to 8.76 eV using the CCSD(T)//B3LYP level of theory. It was found that the AEAs of gallium selenides do not depend solely on the electrophilicity of the clusters but also on their electronic structures. No significant trend was observed in the AIP values and HOMO-LUMO (H-L) gaps with increase in cluster size of the mono and digallium selenide series. Among the dissociation channels, the decomposition of GaSe4???GaSe2?+?Se2 was found to be thermodynamically most favored. Furthermore, the AEAs of GaSe2, GaSe3, GaSe4 and Ga2Se4 were found to exceed that of the chlorine atom and are therefore termed as 'superhalogens'. Finally, the AEAs of the Ga2X n  (X?=?O-Se; n?=?2-4) series were found to be almost similar. PMID:25677451

Seeburrun, Neelum; Archibong, Edet F; Ramasami, Ponnadurai

2015-03-01

44

Determining some properties of molten zinc selenide and calculating the composition on crystallization  

SciTech Connect

The properties of molten zinc selenide are considered which give an approximate analytic description of the composition change in directional crystallization. The volume change in crystallization and the zinc partition coefficient between liquid and crystal have been determined in the quenching of molten zinc selenide. These quantities have been used to estimate the density of the liquid and the solubility of argon in it.

Kulakov, M.P.; Fadeev, A.V.; Kolesnikov, N.N.

1986-08-01

45

Preparation of Cadmium Selenide-Polyolefin Composites from Functional Phosphine Oxides and Ruthenium-Based  

E-print Network

Preparation of Cadmium Selenide-Polyolefin Composites from Functional Phosphine OxidesVersity of Massachusetts, Amherst, Massachusetts 01003 Received November 21, 2001 Abstract: Cadmium selenide nanoparticles by employing more easily handled cadmium sources, such as CdO. Both methods give well-defined nanoparticles

46

Cadmium selenide nanocrystals as white-light phosphors  

NASA Astrophysics Data System (ADS)

Recently, there has been great interest in developing direct white-light phosphors for solid state lighting. Current commercial white light emitting diodes (LEDs) rely on complicated fabrication methods to produce white light. Utilizing magic-sized, white-light emitting cadmium selenide (CdSe) nanocrystals as a direct white-light phosphor eliminates the need for complex doping schemes and deposition techniques. Herein we report preliminary data representing the first elementary steps in designing and optimizing device architectures for building high-quality, highly efficient white-light emitting LEDs for solid state lighting.

Gosnell, Jonathan D.; Schreuder, Michael A.; Bowers, Michael J., II; Rosenthal, Sandra J.; Weiss, Sharon M.

2006-08-01

47

Fractal simulation of the resistivity and capacitance of arsenic selenide  

SciTech Connect

The temperature dependences of the ac resistivity R and ac capacitance C of arsenic selenide were measured more than four decades ago [V. I. Kruglov and L. P. Strakhov, in Problems of Solid State Electronics, Vol. 2 (Leningrad Univ., Leningrad, 1968)]. According to these measurements, the frequency dependences are R {proportional_to} {omega}{sup -0.80{+-}0.01} and {Delta}C {proportional_to} {omega}{sup -0.120{+-}0.006} ({omega} is the circular frequency and {Delta}C is measured from the temperature-independent value C{sub 0}). According to fractal-geometry methods, R {proportional_to} {omega}{sup 1-3/h} and {Delta}C {proportional_to} {omega}{sup -2+3/h}, where h is the walk dimension of the electric current in arsenic selenide. Comparison of the experimental and theoretical results indicates that the walk dimensions calculated from the frequency dependences of resistivity and capacitance are h{sub R} = 1.67 {+-} 0.02 and h{sub C} = 1.60 {+-} 0.08, which are in agreement with each other within the measurement errors. The fractal dimension of the distribution of conducting sections is D = 1/h = 0.6. Since D < 1, the conducting sections are spatially separated and form a Cantor set.

Balkhanov, V. K., E-mail: ballar@yandex.ru; Bashkuev, Yu. B. [Russian Academy of Sciences, Division of Physical Problems, Buryat Scientific Center, Siberian Branch (Russian Federation)

2010-03-15

48

Sodium Selenide Toxicity Is Mediated by O2-Dependent Gerald Peyroche1.  

E-print Network

spin resonance upon exposure of a solution of sodium selenide to O2. Finally we showed that, in vivo to this work. Introduction Selenium is mainly known as an essential micronutrient of many living species

Paris-Sud XI, Université de

49

Chromium-doped zinc selenide gain media: From synthesis to pulsed mid-infrared laser operation  

E-print Network

This paper provides an overview of the experimental work performed in our research group on the synthesis, spectroscopic investigation, and laser characterization of chromium-doped zinc selenide (Cr[superscript 2+]:ZnSe). ...

Demirbas, Umit

50

Growth of zinc selenide crystals by physical vapor transport in microgravity  

NASA Technical Reports Server (NTRS)

The growth of single crystals of zinc selenide was carried out by both closed ampoule physical vapor transport and effusive ampoule physical vapor transport (EAPVT). The latter technique was shown to be a much more efficient method for the seeded growth of zinc selenide, resulting in higher transport rates. Furthermore, EAPVT work on CdTe has shown that growth onto /n11/ seeds is advantageous for obtaining reduced twinning and defect densities in II-VI sphalerite materials.

Rosenberger, Franz

1995-01-01

51

Observation of inverse spin Hall effect in bismuth selenide  

NASA Astrophysics Data System (ADS)

Bismuth Selenide (Bi2Se3) is a topological insulator exhibiting helical spin polarization and strong spin-orbit coupling. The spin-orbit coupling links the charge current to spin current via the spin Hall effect (SHE). We demonstrate a Bi2Se3 spin detector by injecting the pure spin current from a magnetic permalloy layer to a Bi2Se3 thin film and detect the inverse SHE in Bi2Se3. The spin Hall angle of Bi2Se3 is found to be 0.0093 ± 0.0013 and the spin diffusion length in Bi2Se3 to be 6.2 ± 0.15 nm at room temperature. Our results suggest that topological insulators with strong spin-orbit coupling can be used in functional spintronic devices.

Deorani, Praveen; Son, Jaesung; Banerjee, Karan; Koirala, Nikesh; Brahlek, Matthew; Oh, Seongshik; Yang, Hyunsoo

2014-09-01

52

Silicon nanowire-silver indium selenide heterojunction photodiodes  

NASA Astrophysics Data System (ADS)

Structural and optoelectronic properties of silicon (Si) nanowire-silver indium selenide (AgInSe2) thin film heterojunctions were investigated. The metal-assisted etching method was employed to fabricate vertically aligned Si nanowire arrays. Stoichiometric AgInSe2 films were then deposited onto the nanowires using co-sputtering and sequential selenization techniques. It was demonstrated that the three-dimensional interface between the Si nanowire arrays and the AgInSe2 thin film significantly improved the photosensitivity of the heterojunction diode compared to the planar reference. The improvements in device performance are discussed in terms of interface state density, reflective losses and surface recombination of the photogenerated carriers, especially in the high-energy region of the spectrum.

Kulakci, Mustafa; Colakoglu, Tahir; Ozdemir, Baris; Parlak, Mehmet; Emrah Unalan, Husnu; Turan, Rasit

2013-09-01

53

Silicon nanowire-silver indium selenide heterojunction photodiodes.  

PubMed

Structural and optoelectronic properties of silicon (Si) nanowire-silver indium selenide (AgInSe2) thin film heterojunctions were investigated. The metal-assisted etching method was employed to fabricate vertically aligned Si nanowire arrays. Stoichiometric AgInSe2 films were then deposited onto the nanowires using co-sputtering and sequential selenization techniques. It was demonstrated that the three-dimensional interface between the Si nanowire arrays and the AgInSe2 thin film significantly improved the photosensitivity of the heterojunction diode compared to the planar reference. The improvements in device performance are discussed in terms of interface state density, reflective losses and surface recombination of the photogenerated carriers, especially in the high-energy region of the spectrum. PMID:23975141

Kulakci, Mustafa; Colakoglu, Tahir; Ozdemir, Baris; Parlak, Mehmet; Unalan, Husnu Emrah; Turan, Rasit

2013-09-20

54

Preparation of copper indium diselenide by selenization of copper indium oxide  

NASA Astrophysics Data System (ADS)

A process is reported for preparation of thin films of copper indium diselenide (CIS). This process involves two steps: (a) formation of Cu2In2O5 by spray pyrolysis and (b) reaction of Cu2In2O5 with selenium vapor to form CIS. The purity of the CIS prepared by this method can approach that of the material prepared by vacuum deposition methods because highly purified water and nitrate salts can be used in the spray pyrolysis step, and the purity of the selenium used in the second step can be identical to that used in any of the vacuum processes. This two-step process appears to have general applicability; we have been able to prepare a variety of sulfides and tellurides in addition to selenides. The advantage of this process is that any metal ion added to the spray solution is incorporated in the oxide and remains in the selenide after the selenization. Comparison of the Cu/In ratios of the selenide films with those of the precursor oxide films shows that there was a slight decrease in the copper content when the oxide was converted to the selenide. The consistency of the composition of the films prepared at 400 °C is comparable to that of films prepared by the other methods such as thermal processing of elemental layers and reactive sputtering of Cu and In with selenium vapor. Auger composition studies indicated that selenium substitution occurred stepwise. The x-ray-diffraction data for CIS were consistent with a chalcopyrite phase. The data for the resistivity and Hall-effect measurements at room temperature indicated a marked dependence of the resistivity and the hole density on the Cu/In atomic ratio. When this ratio was around 1.45, the resistivity had low values around 30 ? cm, and the hole density was in the 1017 cm-3 range. A direct band gap of 0.95 eV was determined from the optical-absorption spectrum of this material.

Weng, Shixing; Cocivera, Michael

1993-08-01

55

Device physics of copper(indium,gallium)selenide(2) thin-film solar cells  

NASA Astrophysics Data System (ADS)

Thin-film solar cells have the potential to be an important contributor to the global energy demand by the mid-21st-century. Cu(In,Ga)Se 2 (CIGS) solar cells, which have achieved laboratory efficiencies close to 20%, are highly attractive, because their band gap is near the optimal value, their polycrystallinity is not significantly detrimental to their performance, and the broad choice of heterojunction partners available allows additional degrees of freedom for optimizing their performance. Although steady progress has been made for CIGS solar cells, this progress has largely been driven by empirical optimization rather than by in-depth understanding of appropriate physical models. This thesis is intended to fill some of the gaps that exist between state-of-the-art experimental solar cells and their device physics. The level of complexity involved is largely prohibitive to analytical treatment and, hence, numerical approaches are primarily utilized. The dominant topics for CIGS solar cells covered in this dissertation are (1) variation in the Ga/(Ga+In) stoichiometry ("grading"), (2) the formation of "good" heterojunctions, (3) photoconductive effects in window or buffer materials, (4) the apparently benign or even beneficial presence of grain-boundaries (GBs), including a discussion of charged GBs and the effects of Cu-depletion near GBs. This work establishes a baseline model for CIGS solar cells and, from this starting point, the device physics relating to these questions is discussed and principles are identified that apply to a broad range of devices. CIGS grading is shown to have only small potential to improve device performance. This conclusion conflicts with earlier studies, and it is shown that the difference arises in the evaluation of the grading benefit, in particular, the proper choice of the reference performance. Band-gap increases toward the front of the device are most likely detrimental, while band-gap increases toward the back can be modestly beneficial. The popular "double grading" approach achieves only very small additional gains over the simple back grading approach. Very thin-absorber cells can benefit substantially from back grading, because in this case, grading can mitigate detrimental back-contact surface recombination. The window/absorber interface is studied and, in good agreement with experiments, a limitation of the open-circuit voltage is observed for wide-band-gap CdS/CIGS solar cells. (Abstract shortened by UMI.)

Gloeckler, Markus

2005-11-01

56

Structural, electrical and optical properties of copper selenide thin films deposited by chemical bath deposition technique  

Microsoft Academic Search

A low cost chemical bath deposition (CBD) technique has been used for the preparation of Cu2-xSe thin films on glass substrates. Structural, electrical and optical properties of these films were investigated. X-ray diffraction (XRD) study of the Cu2-xSe films annealed at 523 K suggests a cubic structure with a lattice constant of 5.697 Å. Chemical composition was investigated by X-ray

Al-Mamun; A. B. M. O. Islam; A. H. Bhuiyan

2005-01-01

57

Structure-fluctuation-induced abnormal thermoelectric properties in semiconductor copper selenide  

SciTech Connect

Thermoelectric effects and related technologies have attracted a great interest due to the world-wide energy harvesting. Thermoelectricity has usually been considered in the context of stable material phases. Here we report that the fluctuation of structures during the second-order phase transition in Cu2Se semiconductor breaks the conventional trends of thermoelectric transports in normal phases, leading to a critically phase-transition-enhanced thermoelectric figure of merit zT above unity at 400K, a three times larger value than for the normal phases. Dynamic structural transformations introduce intensive fluctuations and extreme complexity, which enhance the carrier entropy and thus the thermopower, and strongly scatter carriers and phonons as well to make their transports behave critically.

Liu, Huili [Chinese Academy of Sciences; Shi, Xun [Chinese Academy of Sciences; Kirkham, Melanie J [ORNL; Wang, Hsin [ORNL; Li, Qiang [Brookhaven National Laboratory (BNL); Uher, Ctirad [University of Michigan; Zhang, Wenqing [Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS); Chen, Lidong [Chinese Academy of Sciences

2013-01-01

58

Long-term performance analysis of copper indium gallium selenide thin-film photovoltaic modules  

NASA Astrophysics Data System (ADS)

Current accelerated qualification tests of photovoltaic (PV) modules mostly assist in avoiding premature failures but can neither duplicate changes occurring in the field nor predict useful product lifetime. Therefore, outdoor monitoring of field-deployed thin-film PV modules was undertaken at FSEC with the goal of assessing their performance in hot and humid climate under high system-voltage operation. Significant and comparable degradation rate of -5.13±1.53% and -4.5±1.46% per year was found using PVUSA type regression analysis for the positive and negative strings, respectively of 40W glass-to-glass Cu-In-Ga-Se (CIGS) thin-film PV modules in the hot and humid climate of Florida. Using the current-voltage measurements, it was found that the performance degradation within the PV array was mainly due to a few (8% to 12%) modules that had substantially higher degradation. The remaining modules within the array continued to show reasonable performance (>96% of the rated power after ˜ four years).

Kaul, Ashwani; Pethe, Shirish A.; Dhere, Neelkanth G.

2012-01-01

59

Copper hypersensitivity.  

PubMed

The world production of copper is steadily increasing. Although humans are widely exposed to copper-containing items on the skin and mucosa, allergic reactions to copper are only infrequently reported. To review the chemistry, biology and accessible data to clarify the implications of copper hypersensitivity, a database search of PubMed was performed with the following terms: copper, dermatitis, allergic contact dermatitis, contact hypersensitivity, contact sensitization, contact allergy, patch test, dental, IUD, epidemiology, clinical, and experimental. Human exposure to copper is relatively common. As a metal, it possesses many of the same qualities as nickel, which is a known strong sensitizer. Cumulative data on subjects with presumed related symptoms and/or suspected exposure showed that a weighted average of 3.8% had a positive patch test reaction to copper. We conclude that copper is a very weak sensitizer as compared with other metal compounds. However, in a few and selected cases, copper can result in clinically relevant allergic reactions. PMID:25098945

Fage, Simon W; Faurschou, Annesofie; Thyssen, Jacob P

2014-10-01

60

Contrasting role of antimony and bismuth dopants on the thermoelectric performance of lead selenide.  

PubMed

Increasing the conversion efficiency of thermoelectric materials is a key scientific driver behind a worldwide effort to enable heat to electricity power generation at competitive cost. Here we report an increased performance for antimony-doped lead selenide with a thermoelectric figure of merit of ~1.5 at 800?K. This is in sharp contrast to bismuth doped lead selenide, which reaches a figure of merit of <1. Substituting antimony or bismuth for lead achieves maximum power factors between ~23-27??W?cm(-1)?K(-2) at temperatures above 400?K. The addition of small amounts (~0.25?mol%) of antimony generates extensive nanoscale precipitates, whereas comparable amounts of bismuth results in very few or no precipitates. The antimony-rich precipitates are endotaxial in lead selenide, and appear remarkably effective in reducing the lattice thermal conductivity. The corresponding bismuth-containing samples exhibit smaller reduction in lattice thermal conductivity. PMID:24784991

Lee, Yeseul; Lo, Shih-Han; Chen, Changqiang; Sun, Hui; Chung, Duck-Young; Chasapis, Thomas C; Uher, Ctirad; Dravid, Vinayak P; Kanatzidis, Mercouri G

2014-01-01

61

Copper Metallochaperones  

PubMed Central

The current state of knowledge on how copper metallochaperones support the maturation of cuproproteins is reviewed. Copper is needed within mitochondria to supply the CuA and intramembrane CuB sites of cytochrome oxidase, within the trans-Golgi network to supply secreted cuproproteins and within the cytosol to supply superoxide dismutase 1 (Sod1). Subpopulations of copper-zinc superoxide dismutase also localize to mitochondria, the secretory system, the nucleus and, in plants, the chloroplast, which also requires copper for plastocyanin. Prokaryotic cuproproteins are found in the cell membrane and in the periplasm of gram-negative bacteria. Cu(I) and Cu(II) form tight complexes with organic molecules and drive redox chemistry, which unrestrained would be destructive. Copper metallochaperones assist copper in reaching vital destinations without inflicting damage or becoming trapped in adventitious binding sites. Copper ions are specifically released from copper metallochaperones upon contact with their cognate cuproproteins and metal transfer is thought to proceed by ligand substitution. PMID:20205585

Robinson, Nigel J.; Winge, Dennis R.

2014-01-01

62

Two-dimensional tin selenide nanostructures for flexible all-solid-state supercapacitors.  

PubMed

Due to their unique electronic and optoelectronic properties, tin selenide nanostructures show great promise for applications in energy storage and photovoltaic devices. Despite the great progress that has been achieved, the phase-controlled synthesis of two-dimensional (2D) tin selenide nanostructures remains a challenge, and their use in supercapacitors has not been explored. In this paper, 2D tin selenide nanostructures, including pure SnSe2 nanodisks (NDs), mixed-phase SnSe-SnSe2 NDs, and pure SnSe nanosheets (NSs), have been synthesized by reacting SnCl2 and trioctylphosphine (TOP)-Se with borane-tert-butylamine complex (BTBC) and 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone. Utilizing the interplay of TOP and BTBC and changing only the amount of BTBC, the phase-controlled synthesis of 2D tin selenide nanostructures is realized for the first time. Phase-dependent pseudocapacitive behavior is observed for the resulting 2D nanostructures. The specific capacitances of pure SnSe2 NDs (168 F g(-1)) and SnSe NSs (228 F g(-1)) are much higher than those of other reported materials (e.g., graphene-Mn3O4 nanorods and TiN mesoporous spheres); thus, these tin selenide materials were used to fabricate flexible, all-solid-state supercapacitors. Devices fabricated with these two tin selenide materials exhibited high areal capacitances, good cycling stabilities, excellent flexibilities, and desirable mechanical stabilities, which were comparable to or better than those reported recently for other solid-state devices based on graphene and 3D GeSe2 nanostructures. Additionally, the rate capability of the SnSe2 NDs device was much better than that of the SnSe NS device, indicating that SnSe2 NDs are promising active materials for use in high-performance, flexible, all-solid-state supercapacitors. PMID:24601530

Zhang, Chunli; Yin, Huanhuan; Han, Min; Dai, Zhihui; Pang, Huan; Zheng, Yulin; Lan, Ya-Qian; Bao, Jianchun; Zhu, Jianmin

2014-04-22

63

The ground and excited states of hydrogen sulfide, methanethiol, and hydrogen selenide  

Microsoft Academic Search

Ab initio SCF and CI investigations of the ground and excited singlet electronic states of hydrogen sulfide 1, methanethiol 2, and hydrogen selenide 3 have been carried out. The moderately large atomic basis sets are augmented by bond functions for polarization and by sets of diffuse s and p functions to enable the description of the lower Rydberg excited states.

Arvi Rauk; Scott Collins

1984-01-01

64

Synthesis and optical properties of cadmium selenide quantum dots for white light-emitting diode application  

SciTech Connect

Highlights: ? Stable CdSe QDs were synthesized by the one-step and two-level process respectively. ? The fabricated white LEDs show good white balance. ? CdSe QDs present well green to yellow band luminescence. ? CdSe QDs displayed a broad excitation band. - Abstract: Yellow light-emitting cadmium selenide quantum dots were synthesized using one-step and two-step methods in an aqueous medium. The structural luminescent properties of these quantum dots were investigated. The obtained cadmium selenide quantum dots displayed a broad excitation band suitable for blue or near-ultraviolet light-emitting diode applications. White light-emitting diodes were fabricated by coating the cadmium selenide samples onto a 460 nm-emitting indium gallium nitrite chip. Both samples exhibited good white balance. Under a 20 mA working current, the white light-emitting diode fabricated via the one-step and two-step methods showed Commission Internationale de l’Éclairage coordinates at (0.27, 0.23) and (0.27, 0.33), respectively, and a color rendering index equal to 41 and 37, respectively. The one-step approach was simpler, greener, and more effective than the two-step approach. The one-step approach can be enhanced by combining cadmium selenide quantum dots with proper phosphors.

Xu, Xianmei; Wang, Yilin; Gule, Teri; Luo, Qiang [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 53000 (China); Zhou, Liya, E-mail: zhouliyatf@163.com [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 53000 (China); Gong, Fuzhong [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 53000 (China)

2013-03-15

65

Electroelastic Properties of the Sulfides, Selenides, and Tellurides of Zinc and Cadmium  

Microsoft Academic Search

A complete set of elastic, piezoelectric, and dielectric constants is presented for the sulfides, selenides, and tellurides of zinc and cadmium. The piezoelectric constants for the hexagonal crystals in this group are markedly higher than for the cubic crystals. An elementary model theory applied to these data leads to electric charges on the metal atom increasing from +0.066 e for

Don Berlincourt; Hans Jaffe; L. R. Shiozawa

1963-01-01

66

Draft Genome Sequence of Pseudomonas aeruginosa Strain RB, a Bacterium Capable of Synthesizing Cadmium Selenide Nanoparticles  

PubMed Central

Pseudomonas aeruginosa strain RB is a bacterium capable of synthesizing cadmium selenide (CdSe) nanoparticles and was isolated from a soil sample. Here, we present the draft genome sequence of P. aeruginosa strain RB. To the best of our knowledge, this is the first report of a draft genome of a CdSe-synthesizing bacterium. PMID:24831140

Ayano, Hiroyuki; Kuroda, Masashi; Soda, Satoshi

2014-01-01

67

Enhancement of thermoelectric figure-of-merit by resonant states of aluminium doping in lead selenide  

E-print Network

By adding aluminium (Al) into lead selenide (PbSe), we successfully prepared n-type PbSe thermoelectric materials with a figure-of-merit (ZT) of 1.3 at 850 K. Such a high ZT is achieved by a combination of high Seebeck ...

Zhang, Qinyong

68

New group 11 complexes with metal-selenium bonds of methyldiphenylphosphane selenide: a solid state, solution and theoretical investigation.  

PubMed

Reactions between methyldiphenylphosphane selenide, SePPh(2)Me, and different group 11 metal starting materials {CuCl, [CuNO(3)(PPh(3))(2)], AgOTf, [AgOTf(PPh(3))] (OTf = OSO(2)CF(3)), [AuCl(tht)], [Au(C(6)F(5))(tht)] and [Au(C(6)F(5))(3)(tht)] (tht = tetrahydrothiophene)} were performed in order to obtain several new species with metal-selenium bonds. The new complexes [CuCl(SePPh(2)Me)] (1), [AgOTf(SePPh(2)Me)] (2), [AuCl(SePPh(2)Me)] (5), [Au(C(6)F(5))(SePPh(2)Me)] (6) and [Au(C(6)F(5))(3)(SePPh(2)Me)] (7) were isolated and structurally characterized in solution by multinuclear NMR spectroscopy ((1)H, (31)P, (77)Se and (19)F where appropriate). Solid products were isolated also from the reactions between SePPh(2)Me and [CuNO(3)(PPh(3))(2)] or [AgOTf(PPh(3))], respectively. NMR experiments, including low temperature (1)H and (31)P NMR, revealed for them a dynamic behaviour in solution, involving the transfer of selenium from PPh(2)Me to PPh(3). In case of the isolated silver(i) containing solid an equilibrium between, respectively, monomeric [AgOTf(PPh(3))(SePPh(2)Me)] (3) and [AgOTf(PPh(2)Me)(SePPh(3))] (4), and dimeric [Ag(PPh(3))(?-SePPh(2)Me)](2)(OTf)(2) (3a) and [Ag(PPh(2)Me)(?-SePPh(3))](2)(OTf)(2) (4a) species was observed in solution. In case of the isolated copper(i) containing solid the NMR studies brought no clear evidence for a similar behaviour, but it can not be excluded in a first stage of the reaction. However the transfer of selenium between the two triorganophosphanes takes place also in this case, but the NMR spectra suggest that the final reaction mixture contains the free triorganophospane selenides SePPh(2)Me and SePPh(3) as well as the complex species [CuNO(3)(PPh(3))(2)], [CuNO(3)(PPh(2)Me)(2)] and [CuNO(3)(PPh(3))(PPh(2)Me)] in equilibrium. Single-crystal X-ray diffraction studies revealed monomeric structures for the gold(I) 6 and gold(III) 7 complexes. In case of compound 6 weak aurophilic gold(I)···gold(I) contacts were also observed in the crystal. DFT calculations were performed in order to understand the solution behaviour of the silver(I) and copper(I) species containing both P(III) and P(V) ligands, to verify the stability of possible dimeric species and to account for the aurophilic interactions found for 6. In addition, the nature of the electronic transitions involved in the absorption/emission processes observed for 6 and 7 in the solid state were also investigated by means of TD-DFT calculations. PMID:21993712

Pop, Alexandra; Silvestru, Anca; Gimeno, M Concepción; Laguna, Antonio; Kulcsar, Monika; Arca, Massimiliano; Lippolis, Vito; Pintus, Anna

2011-12-14

69

Potassium silver tin selenide, K2Ag2Sn2Se6  

E-print Network

Acta Crystallographica Section C Crystal Structure Communications ISSN 0108-2701 Figure 1 (a) View of KPotassium silver tin selenide, K2Ag2Sn2Se6 Hongyou Guo,a * Zenghe Li,a Lin Yang,a Ping Wang-dimensional chain structure consisting of K+ cations and one-dimensional [Ag2Sn2Se6]2Ã? anions. The chain

Li, Jing

70

A hybrid linkage mode between T2,2 and T3 selenide clusters.  

PubMed

A multi-level 3D selenide framework in an In(3+)-Ge(4+) system was synthesized. The interconnection between super-supertetrahedral T2,2 and supertetrahedral T3 clusters via their terminal Se(2-) leads to a previously unknown hybrid T2,2-T3 linkage mode. The synthetic realization of this material represents another new level of complexity and demonstrates the versatility in the construction and property-engineering of cluster-based semiconducting materials. PMID:25659118

Han, Xiaohui; Xu, Jin; Wang, Zhenqing; Liu, Dan; Wang, Cheng

2015-02-17

71

Spectroscopic ellipsometry studies on vacuum-evaporated zinc selenide thin film  

NASA Astrophysics Data System (ADS)

Optical constants of vacuum-deposited Zinc selenide (ZnSe) film from far infrared to near ultraviolet spectral region (270nm-30?m) have been determined by variable angle spectroscopic ellipsometry. The surface roughness layer and interface layer between ZnSe film and crystalline silicon have been modeled with Bruggeman effective medium approximation (BEMA). To evaluate the microstructure of ZnSe film, X-ray diffraction (XRD) measurements are also performed.

Gao, Weidong

2009-05-01

72

Copper peroxide  

NASA Technical Reports Server (NTRS)

A number of oxidizing agents, including chlorine, bromine, ozone and other peroxides, were allowed to act on copper solutions with the intention of forming copper peroxide. The only successful agent appears to be hydrogen peroxide. It must be used in a neutral 50 to 30 percent solution at a temperature near zero. Other methods described in the literature apparently do not work. The excess of hydrogen must be quickly sucked out of the brown precipitate, which it is best to wash with alcohol and ether. The product, crystalline under a microscope, can be analyzed only approximately. It approaches the formula CuO2H2O. In alkaline solution it appears to act catalytically in causing the decomposition of other peroxides, so that Na2O2 cannot be used to prepare it. On the addition of acids the H2O2 is regenerated. The dry substance decomposes much more slowly than the moist but is not very stable.

Moser, L.

1988-01-01

73

COPPER AND BRAIN FUNCTION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Increasing evidence shows that brain development and function are impaired when the brain is deprived of copper either through dietary copper deficiency or through genetic defects in copper transport. A number of copper-dependent enzymes whose activities are lowered by copper deprivation form the ba...

74

Lab Tracker and Copper Calculator  

MedlinePLUS

... Lab Tracker and Copper Calculator Serum Copper (mcg/dl) Ceruloplasmin (mg/dl) Non-Ceruloplasmin Copper Serum Copper (micromoles/liter) Ceruloplasmin ( ... Copper per 24 hours (micrograms) Copper concentration (mcg/dl) Volume (liters) Copper per 24 hours (micrograms) Copper ...

75

Role of copper transporters in copper homeostasis.  

PubMed

Copper is a redox active metal that is essential for biological function. Copper is potentially toxic; thus, its homeostasis is carefully regulated through a system of protein transporters. Copper is taken up across the lumen surface of the small intestinal microvilli as cuprous ion by Ctr1. Cupric ion may also be taken up, but those processes are less well understood. Within the cell, intestinal as well as others, copper is escorted to specific compartments by metallochaperones. One, CCS, donates copper to superoxide dismutase. Another, COX17, delivers copper to additional chaperones within the mitochondria for synthesis of cytochrome c oxidase. A third chaperone, Atox1, delivers copper to the secretory pathway by docking with 2 P-type ATPases. One, ATP7A, is the protein nonfunctional in Menkes disease. This protein is required for cuproenzyme biosynthesis, and in the enterocyte it is required for copper efflux to portal blood. The second, ATP7B, predominantly expressed in liver, is required for copper metallation of ceruloplasmin and biliary copper excretion. Mutations in ATP7B lead to Wilson disease. Additional intracellular hepatic copper-binding proteins COMMD1 (copper metabolism MURR1 domain) and XIAP (X-linked inhibitor of apoptosis protein) may also be required for excretion. Other proteins involved in copper homeostasis may include metallothionein and amyloid precursor protein. Plasma protein transport of copper from the intestine to liver and in systemic circulation probably includes both albumin and alpha2-macroglobulin. Changes in the expression of copper "transporters" may be useful to monitor copper status of humans, provided a suitable cell type can be sampled. PMID:18779302

Prohaska, Joseph R

2008-09-01

76

Pairing strength and symmetries of 122 iron selenides in comparison with iron pnictides  

NASA Astrophysics Data System (ADS)

High temperature superconductivity with comparable transition temperatures has been observed in the vicinity of an antiferromagnetic phase, in both 122-alkaline iron selenides and 122-iron pnictides. In contrast to iron pnictides, where the parent state is an antiferromagnetic semimetal, the parent state of 122-iron selenides is a large moment, antiferromagnetic insulator. This provides a clear indication of strong electronic correlations. The 122-selenides possess only electron pockets, while the pnictides have both hole and electron pockets. In addition, the observed block spin magnetic order in 122-selenides can not be explained by Fermi surface nesting. At the same time, the comparable Tc suggests a commonality in the underlying mechanism for superconductivity in the two classes of materials. Motivated by these observations and considerations, we present a comparative strong coupling analysis of the pairing strength and symmetries in these two classes of materials [1,2]. The analysis of appropriate five orbital t-J1-J2 models, reveals a similar pairing phase diagram for both materials, with A1g s(x^2y^2) and B1g d(x^2-y^2) as two dominant pairing channels. The pairing amplitudes in both materials are of comparable strength, making it natural for a comparable maximum Tc . In contrast to the pnictides case, an A1g s(x^2+y^2) state is not competitive, making the dominant pairing channels fully gapped. We also discuss the magnetism of the vacancy-ordered insulating 122 iron selenides [3], showing that the observed block-spin state occurs over a wide parameter range. The predicted magnetic excitation spectrum has been verified by inelastic neutron scattering experiments. Our study also reveals some commonality with the magnetism of the parent iron pnictides [4].[4pt] Work was done in collaboration with Rong Yu, Predrag Nikolic, Jian-Xin Zhu, Qimiao Si and Elihu Abrahams. [4pt] [1] Rong Yu, Pallab Goswami, Qimiao Si, Predrag Nikolic, and Jian-Xin Zhu, ``Pairing strength and symmetries of 122 iron selenides in comparison with iron pnictides,'' to be published; arXiv:1103.3259. [0pt] [2] Pallab Goswami et al, ``Superconductivity in Multi-orbital t-J1-J2 Model and its Implications for Iron Pnictides,'' Europhys. Lett. 91, 37006 (2010).[0pt] [3] Rong Yu, Pallab Goswami, and Qimiao Si, ``The magnetic phase diagram of an extended J1-J2 model on a modulated square lattice and its implications for the antiferromagnetic phase of KyFexSe2,'' Phys. Rev. B 84, 094451 (2011). [0pt] [4] Pallab Goswami et al, ``Spin Dynamics of a J1-J2 Antiferromagnet and its Implications for Iron Pnictides,'' Phys. Rev. B 84, 155108 (2011).

Goswami, Pallab

2012-02-01

77

Selenide and telluride glasses for mid-infrared bio-sensing  

NASA Astrophysics Data System (ADS)

Fiber Evanescent Wave Spectroscopy (FEWS) is an efficient way to collect optical spectra in situ, in real time and even, hopefully, in vivo. Thanks to selenide glass fibers, it is possible to get such spectra over the whole mid-infrared range from 2 to 12 ?m. This working window gives access to the fundamental vibration band of most of biological molecules. Moreover selenide glasses are stable and easy to handle, and it is possible to shape the fiber and create a tapered sensing head to drastically increase the sensitivity. Within the past decades, numerous multi-disciplinary studies have been conducted in collaboration with the City Hospital of Rennes. Clinical trials have provided very promising results in biology and medicine which have led to the creation in 2011 of the DIAFIR Company dedicated to the commercialization of fiber-based infrared biosensors. In addition, new glasses based on tellurium only have been recently developed, initially in the framework of the Darwin mission led by the European Space Agency (ESA). These glasses transmit light further into the far-infrared and could also be very useful for medical applications in the near future. Indeed, they permit to reach the vibrational bands of biomolecules laying from 12 to 16 ?m where selenide glasses do not transmit light anymore. However, while Se is a very good glass former, telluride glasses tend to crystallize easily due to the metallic nature of Te bonds. Hence, further work is under way to stabilize the glass composition for fibers drawing and to lower the optical losses for improving their sensitivity as bio-sensors.

Cui, Shuo; Chahal, Radwan; Shpotyuk, Yaroslav; Boussard, Catherine; Lucas, Jacques; Charpentier, Frederic; Tariel, Hugues; Loréal, Olivier; Nazabal, Virginie; Sire, Olivier; Monbet, Valérie; Yang, Zhiyong; Lucas, Pierre; Bureau, Bruno

2014-02-01

78

COPPER CORROSION RESEARCH UPDATE  

EPA Science Inventory

Copper release and corrosion related issues continue to be important to many water systems. The objective of this presentation is to discuss the current state of copper research at the USEPA. Specifically, the role of aging on copper release, use of phosphates for copper corrosio...

79

Transparent and flexible nonvolatile memory using poly(methylsilsesquioxane) dielectric embedded with cadmium selenide quantum dots  

NASA Astrophysics Data System (ADS)

In this work, a transparent and flexible nonvolatile memory was fabricated using a solution process. The conduction mechanisms of the metal/insulator/metal structure consisting of cadmium selenide quantum dots embedded in poly(methylsilsesquioxane) dielectric layers were investigated in terms of current–voltage characteristics. The memory device is reprogrammable and stable up to 1 × 104 s with little deterioration and a distinct ON/OFF ratio of 104. Endurance cycle and retention tests of the as-fabricated memory device were also carried out. The results indicate that the device has good operating stability.

Ooi, Poh Choon; Li, Fushan; Perumal Veeramalai, Chandrasekar; Guo, Tailiang

2014-12-01

80

Scaling and spatial analysis of the dielectric response of cadmium selenide nanowires  

NASA Astrophysics Data System (ADS)

Transverse dielectric response of hexagonal cadmium selenide (CdSe) nanowires was investigated using first-principles quantum mechanical calculations. Scaling behavior of polarizability was found to closely follow a simple dielectric cylinder model even for small nanowires with a diameter of a few nanometers. The spatial dependence of the dielectric response in the nanowires was analyzed in terms of maximally localized Wannier functions in order to elucidate the model behavior. Localized d electrons at cadmium atoms were found responsible for the simple analytic scaling of the polarizability, and the dielectric response in the center of nanowire was found converged to that of bulk already for 3 nm diameter nanowires.

Kanai, Yosuke; Cicero, Giancarlo

2014-10-01

81

Copper and Copper Proteins in Parkinson's Disease  

PubMed Central

Copper is a transition metal that has been linked to pathological and beneficial effects in neurodegenerative diseases. In Parkinson's disease, free copper is related to increased oxidative stress, alpha-synuclein oligomerization, and Lewy body formation. Decreased copper along with increased iron has been found in substantia nigra and caudate nucleus of Parkinson's disease patients. Copper influences iron content in the brain through ferroxidase ceruloplasmin activity; therefore decreased protein-bound copper in brain may enhance iron accumulation and the associated oxidative stress. The function of other copper-binding proteins such as Cu/Zn-SOD and metallothioneins is also beneficial to prevent neurodegeneration. Copper may regulate neurotransmission since it is released after neuronal stimulus and the metal is able to modulate the function of NMDA and GABA A receptors. Some of the proteins involved in copper transport are the transporters CTR1, ATP7A, and ATP7B and the chaperone ATOX1. There is limited information about the role of those biomolecules in the pathophysiology of Parkinson's disease; for instance, it is known that CTR1 is decreased in substantia nigra pars compacta in Parkinson's disease and that a mutation in ATP7B could be associated with Parkinson's disease. Regarding copper-related therapies, copper supplementation can represent a plausible alternative, while copper chelation may even aggravate the pathology. PMID:24672633

Rivera-Mancia, Susana; Diaz-Ruiz, Araceli; Tristan-Lopez, Luis; Rios, Camilo

2014-01-01

82

Copper and copper proteins in Parkinson's disease.  

PubMed

Copper is a transition metal that has been linked to pathological and beneficial effects in neurodegenerative diseases. In Parkinson's disease, free copper is related to increased oxidative stress, alpha-synuclein oligomerization, and Lewy body formation. Decreased copper along with increased iron has been found in substantia nigra and caudate nucleus of Parkinson's disease patients. Copper influences iron content in the brain through ferroxidase ceruloplasmin activity; therefore decreased protein-bound copper in brain may enhance iron accumulation and the associated oxidative stress. The function of other copper-binding proteins such as Cu/Zn-SOD and metallothioneins is also beneficial to prevent neurodegeneration. Copper may regulate neurotransmission since it is released after neuronal stimulus and the metal is able to modulate the function of NMDA and GABA A receptors. Some of the proteins involved in copper transport are the transporters CTR1, ATP7A, and ATP7B and the chaperone ATOX1. There is limited information about the role of those biomolecules in the pathophysiology of Parkinson's disease; for instance, it is known that CTR1 is decreased in substantia nigra pars compacta in Parkinson's disease and that a mutation in ATP7B could be associated with Parkinson's disease. Regarding copper-related therapies, copper supplementation can represent a plausible alternative, while copper chelation may even aggravate the pathology. PMID:24672633

Montes, Sergio; Rivera-Mancia, Susana; Diaz-Ruiz, Araceli; Tristan-Lopez, Luis; Rios, Camilo

2014-01-01

83

Spectroscopic characterization of II-VI compounds and application to copper indium selenide-based solar cells  

Microsoft Academic Search

Structures consisting of CuInSe2 films, deposited on molybdenum-coated glass substrates and covered by CdS or ZnO thin films, for application in solar cells, have been characterized by spectroscopic ellipsometry, atomic force microscopy, photoluminescence and photovoltaic response. Computer aided simulations of the photovoltaic operation of these structures have been made to reinforce and complement the results of the characterization studies. The

Heriberto De Jesus Aguilar Juarez

1999-01-01

84

Electron-beam-pumped lasers using heteroepitaxial zinc selenide obtained from organoelemental compounds  

NASA Astrophysics Data System (ADS)

Preliminary results are reported from an investigation of lasers with transverse electron beam pumping using heteroepitaxial ZnSe films grown on GaAs substrates by chemical gas-phase deposition from organoelemental compounds. The zinc selenide films are grown using a setup similar to that described by Stutius (1978) in a slotted reaction vessel. The starting materials are dimethyl zinc, dimethyl selenide, and hydrogen. The substrates are GaAs (100) wafers 300 microns thick and up to 30 mm in diameter polished using a chemical-mechanical method. The temperature of the substrates is varied in the range 500-600 C. The (CH3)2Se:Zn(CH3)2 ratio is 6:1. The rate of growth of the ZnSe films is 0.1-0.2 micron/min. The films, up to 10 microns thick, are of the single crystal type and are mirror smooth. Kikuchi lines are observed in the electron-diffraction patterns of these films.

Bogdankevich, O. V.; Zhuravlev, L. A.; Konovalov, A. D.; Kuznetsov, P. I.; Meerovich, G. A.; Novikov, V. B.; Petrushenko, Iu. V.; Ulasiuk, V. N.; Shemet, V. V.

1983-05-01

85

Transparent metal selenide alloy counter electrodes for high-efficiency bifacial dye-sensitized solar cells.  

PubMed

The exploration of cost-effective and transparent counter electrodes (CEs) is a persistent objective in the development of bifacial dye-sensitized solar cells (DSSCs). Transparent counter electrodes based on binary-alloy metal selenides (M-Se; M=Co, Ni, Cu, Fe, Ru) are now obtained by a mild, solution-based method and employed in efficient bifacial DSSCs. Owing to superior charge-transfer ability for the I(-) /I3 (-) redox couple, electrocatalytic activity toward I3 (-) reduction, and optical transparency, the bifacial DSSCs with CEs consisting of a metal selenide alloy yield front and rear efficiencies of 8.30?% and 4.63?% for Co0.85 Se, 7.85?% and 4.37?% for Ni0.85 Se, 6.43?% and 4.24?% for Cu0.50 Se, 7.64?% and 5.05?% for FeSe, and 9.22?% and 5.90?% for Ru0.33 Se in comparison with 6.18?% and 3.56?% for a cell with an electrode based on pristine platinum, respectively. Moreover, fast activity onset, high multiple start/stop capability, and relatively good stability demonstrate that these new electrodes should find applications in solar panels. PMID:25358619

Duan, Yanyan; Tang, Qunwei; Liu, Juan; He, Benlin; Yu, Liangmin

2014-12-22

86

Influence of indium concentration on the structural and optoelectronic properties of indium selenide thin films  

NASA Astrophysics Data System (ADS)

We have grown indium selenide thin films using magnetron sputtering method. The influence of indium concentration on the structural, optical and electrical properties was studied. The concentration of indium in indium selenide thin films was varied by adjusting the sputtering power from 40 to 80 W while keeping the substrate temperature and argon pressure constant. The ?-phase, which only exists at elevated temperatures in bulk single crystals, can persist at room temperature in the In-rich films. The ?-phase thin film with smaller band gap has an electrical resistivity about four orders of magnitude lower than that of the ?-In2Se3 thin film, which is also stable at room temperature. Furthermore, the single-phase ?-In2Se3 thin film was then assembled in visible-light photodetector which shows a fast, reversible, and stable response. These results indicate the possibility of using ?-In2Se3 thin film in various next-generation photoelectric and optical-memory applications.

Yan, Yong; Li, Shasha; Yu, Zhou; Liu, Lian; Yan, Chuanpeng; Zhang, Yong; Zhao, Yong

2014-12-01

87

A method for analysis of dimethyl selenide and dimethyl diselenide by LC-ICP-DRC-MS.  

PubMed

The aim of this work was to develop a simple and fast high performance liquid chromatography-inductively coupled argon plasma (ICP) mass spectrometry (MS) method capable of separating and detecting the two volatile selenium species dimethyl selenide (DMeSe) and dimethyl diselenide (DMeDSe) in biological samples. Dimethyl selenide and dimethyl diselenide were separated on a short reversed phase column using an eluent containing 40% methanol and detected by dynamic reaction cell ICP-MS monitoring the (80)Se isotope. The limit of detection was 8 nM for both species (corresponding to 0.6 and 1.3 ?g Se/L for DMeDSe and DMeSe, respectively). Both compounds exhibited a linear signal-concentration relationship in the investigated concentration range of 0.1-1 ?M with a precision on the determinations better than 3%. The method was applied for analysis of samples from cancer cell lines incubated with methylseleninic acid, selenomethionine, Se-methylselenocysteine, and sodium selenite. DMeDSe were detected in some samples. The method offers a simple and fast analysis of DMeDSe and DMeSe using standard liquid chromatography coupled with ICP-MS equipment and interfacing. PMID:20890781

Lunøe, Kristoffer; Skov, Søren; Gabel-Jensen, Charlotte; Stürup, Stefan; Gammelgaard, Bente

2010-12-01

88

An Selenide-Based Approach to Photochemical Cleavage of Peptide and Protein Backbones at Engineered Backbone Esters  

PubMed Central

A strategy for photochemical cleavage of peptide and protein backbones is described, which is based on a selenide-mediated cleavage of a backbone ester moiety. Studies in model systems establish the viability of the chemistry and suggest the method could be a valuable tool for chemical biology studies of proteins. PMID:19902952

Eastwood, Amy L.; Blum, Angela P.; Zacharias, Niki M.; Dougherty, Dennis A.

2010-01-01

89

Selenocysteine beta-lyase and methylselenol demethylase in the metabolism of Se-methylated selenocompounds into selenide.  

PubMed

The lyase activity toward Se-methylated selenoamino acids and the demethylase activity toward methylselenol in the metabolism of selenium were characterized in vitro. The beta- and gamma-lyase activities toward selenomethionine (SeMet) and Se-methylselenocysteine (MeSeCys), respectively, were compared under exactly identical conditions by incubating 77Se-SeMet and 76Se-MeSeCys simultaneously in a liver supernatant, and then estimated by the decreases in the labeled starting selenoamino acids (MeSeCys and SeMet), and also by the increases in the labeled enzyme products (methylselenol and selenide) after oxidation to methylseleninic acid (MSA(IV)) and selenite, respectively, by HPLC-inductively coupled plasma-mass spectrometry (ICP-MS). Only 76Se-MeSeCys was decreased and only 76Se-selenite was produced, suggesting that conversion of MeSeCys to methylselenol by beta-lyase followed by that of methylselenol to selenide by demethylase actively occurred in the liver supernatant. The demethylase activity was characterized by incubating 77Se-methylselenol produced in situ from 77Se-MSA(IV) and glutathione in a partially purified enzyme preparation. It was found that demethylation takes place directly through an attack by a hydroxide anion on the methyl group of methylselenol producing selenide and methanol, selenide being detected on HPLC-ICP-MS after oxidation to selenite, and methanol on GC-MS. It was concluded that beta- but not gamma-lyase activity could be detected in a liver supernatant, and that the resulting methylselenol product is demethylated through hydrolysis, with methanol and selenide being produced (MeSeCys-->CH3SeH-->HSeH + CH3OH). PMID:17451884

Suzuki, Kazuo T; Kurasaki, Kazuki; Suzuki, Noriyuki

2007-07-01

90

Demystifying Controlling Copper Corrosion  

EPA Science Inventory

The LCR systematically misses the highest health and corrosion risk sites for copper. Additionally, there are growing concerns for WWTP copper in sludges and discharge levels. There are many corrosion control differences between copper and lead. This talk explains the sometimes c...

91

Copper metabolism of astrocytes  

PubMed Central

This short review will summarize the current knowledge on the uptake, storage, and export of copper ions by astrocytes and will address the potential roles of astrocytes in copper homeostasis in the normal and diseased brain. Astrocytes in culture efficiently accumulate copper by processes that include both the copper transporter Ctr1 and Ctr1-independent mechanisms. Exposure of astrocytes to copper induces an increase in cellular glutathione (GSH) content as well as synthesis of metallothioneins, suggesting that excess of copper is stored as complex with GSH and in metallothioneins. Furthermore, exposure of astrocytes to copper accelerates the release of GSH and glycolytically generated lactate. Astrocytes are able to export copper and express the Menkes protein ATP7A. This protein undergoes reversible, copper-dependent trafficking between the trans-Golgi network and vesicular structures. The ability of astrocytes to efficiently take up, store and export copper suggests that astrocytes play a key role in the supply of neurons with copper and that astrocytes should be considered as target for therapeutic interventions that aim to correct disturbances in brain copper homeostasis. PMID:23503037

Dringen, Ralf; Scheiber, Ivo F.; Mercer, Julian F. B.

2013-01-01

92

Copper metabolism of astrocytes.  

PubMed

This short review will summarize the current knowledge on the uptake, storage, and export of copper ions by astrocytes and will address the potential roles of astrocytes in copper homeostasis in the normal and diseased brain. Astrocytes in culture efficiently accumulate copper by processes that include both the copper transporter Ctr1 and Ctr1-independent mechanisms. Exposure of astrocytes to copper induces an increase in cellular glutathione (GSH) content as well as synthesis of metallothioneins, suggesting that excess of copper is stored as complex with GSH and in metallothioneins. Furthermore, exposure of astrocytes to copper accelerates the release of GSH and glycolytically generated lactate. Astrocytes are able to export copper and express the Menkes protein ATP7A. This protein undergoes reversible, copper-dependent trafficking between the trans-Golgi network and vesicular structures. The ability of astrocytes to efficiently take up, store and export copper suggests that astrocytes play a key role in the supply of neurons with copper and that astrocytes should be considered as target for therapeutic interventions that aim to correct disturbances in brain copper homeostasis. PMID:23503037

Dringen, Ralf; Scheiber, Ivo F; Mercer, Julian F B

2013-01-01

93

A novel one-pot route for the synthesis of water-soluble cadmium selenide nanoparticles  

NASA Astrophysics Data System (ADS)

A novel, facile one-pot synthetic route to highly water dispersible and potentially biocompatible CdSe nanoparticles is reported. The monodispersed CdSe particles are passivated by cysteine, with water being the solvent. This route involves the reaction of selenium powder with sodium borohydride to produce selenide ions, followed by the addition of a cadmium salt and L-cysteine ethyl ester hydrochloride. The nanoparticles formed show quantum confinement fluorescing in the blue region. Fourier transform infrared spectroscopy study shows that CdSe nanoparticles are capped through mercapto group of the amino acid cysteine whilst its free amino and carboxylate groups make it amenable to bioconjugation establishing the possibility of using these as fluorescent biomarkers. High-resolution transmission electron spectroscopy images of these materials show well-defined, crystalline nanosized particles. Energy dispersive spectroscopy spectra confirm the presence of the corresponding elements.

Oluwafemi, S. O.; Revaprasadu, N.; Ramirez, A. J.

2008-06-01

94

Gate-dependent carrier diffusion length in lead selenide quantum dot field-effect transistors.  

PubMed

We report a scanning photocurrent microscopy (SPCM) study of colloidal lead selenide (PbSe) quantum dot (QD) thin film field-effect transistors (FETs). PbSe QDs are chemically treated with sodium sulfide (Na2S) and coated with amorphous alumina (a-Al2O3) by atomic layer deposition (ALD) to obtain high mobility, air-stable FETs with a strongly gate-dependent conductivity. SPCM reveals a long photocurrent decay length of 1.7 ?m at moderately positive gate bias that decreases to below 0.5 ?m at large positive gate voltage and all negative gate voltages. After excluding other possible mechanisms including thermoelectric effects, a thick depletion width, and fringing electric fields, we conclude from photocurrent lifetime measurements that the diffusion of a small fraction of long-lived carriers accounts for the long photocurrent decay length. The long minority carrier lifetime is attributed to charge traps for majority carriers. PMID:23802707

Otto, Tyler; Miller, Chris; Tolentino, Jason; Liu, Yao; Law, Matt; Yu, Dong

2013-08-14

95

Silica encapsulation of thiol-stabilized lead selenide (PbSe) quantum dots in aqueous solution  

PubMed Central

Silica encapsulation of lead selenide quantum dots (PbSe QDs) in aqueous solution is reported. Thioglycolic acid (TGA) stabilized PbSe QDs were modified with 3-mercaptopropyl trimethoxysilane (MPS) through vigorous stirring in water for 18–24 h in alkaline solution (pH 10.4–10.6). Silica shell was developed by controlled deposition and precipitation of silicates from sodium silicate solution onto MPS modified QDs surfaces. TEM images showed multiple PbSe QDs encapsulated in silica shell. The size of PbSe-SiO2 core-shell nanocrystals was estimated to be 25–30 nm by TEM. Elemental compositions (Pb, Se and Si) were investigated by EDX analysis. The purified colloids of PbSe-SiO2 QDs were stable for months when kept at 4 °C. PMID:23729944

Primera-Pedrozo, Oliva M.; Ates, Mehmet; Arslan, Zikri

2013-01-01

96

The growth of zinc selenide single crystals by physical vapor transport in microgravity  

NASA Technical Reports Server (NTRS)

Growth and characterization studies will be performed on zinc selenide single crystals. The high temperature outgassing behavior of the silica ampoule material will be studied in order to develop a cleaning and bake-out procedure that will minimize the amount of impurities introduced into the vapor from the ampoule materials and in particular during the seal-off procedure. The outgassing behavior of the ZnSe starting material will be studied during high vacuum refinement at elevated temperatures in order to develop a temperature pressure program that will optimize the removal of impurities while minimizing a shift in stoichiometry due to preferred evaporation of the higher fugacity component. The mass spectrometer system was completed, and after calibration, will be used to perform the above tasks. The system and its operation is described in detail.

Anderson, Elmer E.; Rosenberger, Franz E.; Cheng, Hai-Yuin

1990-01-01

97

Optoelectronic and low temperature thermoelectric studies on nanostructured thin films of silver gallium selenide  

SciTech Connect

Polycrystalline thin films of silver gallium selenide were deposited on ultrasonically cleaned soda lime glass substrates by multi-source vacuum co-evaporation technique. The structural analysis done by X-ray diffraction ascertained the formation of nano structured tetragonal chalcopyrite thin films. The compound formation was confirmed by X-ray photo-electron spectroscopy. Atomic force microscopic technique has been used for surface morphological analysis. Direct allowed band gap ?1.78eV with high absorption coefficient ?10{sup 6}/m was estimated from absorbance spectra. Low temperature thermoelectric effects has been investigated in the temperature range 80–330K which manifested an unusual increase in Seebeck coefficient with negligible phonon drag toward the very low and room temperature regime. The electrical resistivity of these n-type films was assessed to be ?2.6?m and the films showed good photo response.

Jacob, Rajani, E-mail: reenatara@rediffmail.com; Philip, Rachel Reena, E-mail: reenatara@rediffmail.com; Nazer, Sheeba, E-mail: reenatara@rediffmail.com; Abraham, Anitha, E-mail: reenatara@rediffmail.com; Nair, Sinitha B., E-mail: reenatara@rediffmail.com [Thin film research lab, U.C. College, Aluva, Kerala (India); Pradeep, B.; Urmila, K. S. [Solid State Physics Laboratory, Cochin University of Science and Technology, Cochin (India); Okram, G. S. [UGC-DAE CSR, Khandwa Road, Indore-452 001, Madhya Pradesh (India)

2014-01-28

98

Synthesis and characterization of lead selenide nanocrystal quantum dots and wires.  

PubMed

Lead chalcogenide nanocrystalline materials offer possibilities of improving the efficiency of various optoelectric/thermoelectric applications, especially in solar cells, by generating more carriers with incoming photons, or by extending the bandgap toward the infra-red region. In this work, we suggest the synthetic approach of creating extended PbSe structures which shows better performances when incorporated into an electric device. Firstly, we synthesized monodisperse cubic-structured single-crystalline lead selenide nanocrystal quantum dots using lead acetate and oleic acid in non-coordinating solvent without additional surfactants. Also, single-crystal cubic PbSe nanowires were synthesized in a mixture of surfactants such as trioctylphosphine and phenyl ether. Morphologies of wires and dots were precisely controlled via reaction temperature and the surface ligands. Phenyl ether was found to facilitate the oriented attachment. Further, current-voltage characteristics of drop-casted 2D arrays of nanocrystalline materials were examined. PMID:21780455

Seo, Weonsik; Yun, Ju-Hyung; Park, Yun Chang; Han, Chang-Soo; Lee, Jihye; Jeong, Sohee

2011-05-01

99

Novel chemical synthetic route and characterization of zinc selenide thin films  

NASA Astrophysics Data System (ADS)

Zinc selenide (ZnSe) thin film have been deposited using chemical bath method on non-conducting glass substrate in a tartarate bath containing zinc sulfate, ammonia, hydrazine hydrate, sodium selenosulfate in an aqueous alkaline medium at 333 K. The deposition parameter of the ZnSe thin film is interpreted in the present investigation. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), optical absorption, electrical measurements, atomic absorption spectroscopy (AAS). The ZnSe thin layers grown with polycrystalline zinc blende system along with some amorphous phase present in ZnSe film. The direct optical band gap ‘Eg’ for the film was found to be 2.81 eV and electrical conductivity in the order of 10-8(? cm)-1 with n-type conduction mechanism.

Hankare, P. P.; Chate, P. A.; Delekar, S. D.; Asabe, M. R.; Mulla, I. S.

2006-11-01

100

Revealing the preferred interlayer orientations and stackings of two-dimensional bilayer gallium selenide crystals.  

PubMed

Characterizing and controlling the interlayer orientations and stacking orders of two-dimensional (2D) bilayer crystals and van der Waals (vdW) heterostructures is crucial to optimize their electrical and optoelectronic properties. The four polymorphs of layered gallium selenide (GaSe) crystals that result from different layer stackings provide an ideal platform to study the stacking configurations in 2D bilayer crystals. Through a controllable vapor-phase deposition method, bilayer GaSe crystals were selectively grown and their two preferred 0° or 60° interlayer rotations were investigated. The commensurate stacking configurations (AA' and AB stacking) in as-grown bilayer GaSe crystals are clearly observed at the atomic scale, and the Ga-terminated edge structure was identified using scanning transmission electron microscopy. Theoretical analysis reveals that the energies of the interlayer coupling are responsible for the preferred orientations among the bilayer GaSe crystals. PMID:25611050

Li, Xufan; Basile, Leonardo; Yoon, Mina; Ma, Cheng; Puretzky, Alexander A; Lee, Jaekwang; Idrobo, Juan C; Chi, Miaofang; Rouleau, Christopher M; Geohegan, David B; Xiao, Kai

2015-02-23

101

Resonance enhancement of nonlinear photoluminescence in gallium selenide and related compounds  

SciTech Connect

Maker fringe experiments on the layered chalcogenide semiconductor gallium selenide (GaSe) with weak cw diode lasers are presented. It is demonstrated that nonlinear photoluminescence emitted by this material and by the similar compound GaSe{sub 0.9}S{sub 0.1} under illumination with a 632.8-nm He - Ne laser shows very strong resonance enhancement upon heating when the absorption edge and exciton levels are shifted towards the laser line. The photoluminescence appears to be strongest when the energy level of the direct exciton, which emits it, is resonant with the photon energy of the laser. The previously observed enhancement of the photoluminescence by electric fields is interpreted in this context.

Angermann, Ch; Karich, P; Kador, Lothar; Allakhverdiev, K R; Baykara, T; Salaev, E Yu

2012-05-31

102

Achieving higher TC superconductivity in dense cuprates, iron selenides, and hydrocarbons  

NASA Astrophysics Data System (ADS)

Pressure plays an essential role in inducing or tuning superconductivity as well as shedding insight on the mechanism of superconductivity. There are much rich phase diagrams in unconventional superconductors under pressure. Finding ways to control the quantum coherence properties to have a higher critical temperature TC than the material has remains a challenge. Here we will talk about our recent experimental efforts in achieving higher temperature superconductivity in cuprates, iron selenides, and hydrocarbons. We will show how to enhance remarkably TC through the pressure tuning of competing electronic order in multilayer cuprates [1] and how to have superconductivity in two distinct regimes in iron selenides [2,3]. We will present a discovery of an enhancement of TC at more than doubled ambient value in a highly compressed aromatic hydrocarbon [4]. Our results have important implications for designing and engineering superconductors with much higher TCs at ambient conditions.[4pt] [1] X. J. Chen, V. V. Struzhkin, Y. Yu, A. F. Goncharov, C. T. Lin, H. K. Mao, and R. J. Hemley, Nature 466, 950-953 (2010).[0pt] [2] L. L. Sun, X. J. Chen, J. Guo, P. W. Gao, H. D. Wang, M. H. Fang, X. L. Chen, G. F. Chen, Q. Wu, C. Zhang, D. C. Gu, X. L. Dong, K. Yang, A. G. Li, X. Dai, H. K. Mao, and Z. X. Zhao, Nature 483, 67-69 (2012) .[0pt] [3] X. J. Chen, Q. Huang, S. B. Wang, J. X. Zhu, W. Bao, M. H. Fang, J. B. Zhang, L. Y. Tang, Y. M. Xiao, P. Chaw, J. Shu, W. L. Mao, V. V. Struzhkin, R. J. Hemley, and H. K. Mao, unpublished.[0pt] [4] X. J. Chen, X. F. Wang, Z. X. Qin, H. Wu, Q. Z. Huang, T. Muramatsu, J. J. Ying, P. Cheng, Z. J. Xiang, X. H. Chen, W. G. Yang, V. V. Struzhkin, and H. K. Mao, unpublished.

Chen, Xiao-Jia

2013-03-01

103

Synthesis and characterization of a nickel selenide series via a hydrothermal process  

NASA Astrophysics Data System (ADS)

A series of nickel selenides (NiSe and NiSe2) has been successfully synthesized from the reaction of SeCl4 with NiCl2?6H2O in the presence of cetyltrimethyl ammonium bromide (CTAB) as surfactant and hydrazine hydrate (N2H4?H2O) as reductant at 180 °C for 12 h through a simple hydrothermal method. The morphology, phase structure and composition of NixSey can be controlled by adjusting the Ni/Se ratio of the raw materials, the quantity of reductant, the reaction temperature and so forth. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) analysis. It was found that when the ratio of Ni/Se is 1:1 or 3:2, flower-like assemblies of NiSe nanosheets are formed, at 180 °C for 12 h. When the ratio of Ni/Se is 1:2 at 180 °C, the products are found to be the mixture of hexagonal NiSe and cubic NiSe2. With decrease of nickel content in molar ratio of 1:2 (Ni:Se), nanospheres are agglomerated and microstructures are formed. With the reaction temperature decreasing from 180 °C to 120 °C, we reach pure NiSe2 nanoparticles. The formation mechanism of the nickel selenides has been investigated in detail by means of XRD and SEM analyses.

Sobhani, Azam; Salavati-Niasari, Masoud

2014-01-01

104

Electrosynthesis of Cu-Se films on copper electrodes in alkaline media: a voltammetric, electrochemical quartz crystal microbalance and I/t transient study.  

PubMed

The electroformation of Cu-Se phases, obtained by selenizing a thin film of copper deposited on the quartz/gold electrode system, was studied with an electrochemical quartz crystal microbalance (EQCM) and by cyclic voltammetry (CV) in an alkaline solution (0.05 M Na(2)B(4)O(7)) containing selenide ion. Potentiodynamic parameters showed that the formation of the initial Cu-Se phases (Cu(2-x)Se/Cu(3)Se(2)) is ruled by an irreversible diffusion controlled mechanism, where a first electron transfer is the rate-determining step. A CV study was also performed with a bulk copper electrode in 1 M NaOH solution containing selenide ion. The deconvolution of the anodic and cathodic I/E profiles corresponding to the electroformation and electroreduction of the Cu-Se film formed allowed us to establish that, depending on the anodic potential limit of the potentiodynamic scan, the Cu-Se phases formed were either a mixture of Cu(2)(-x)Se/Cu(3)Se(2) or Cu(2-x)Se/Cu(3)Se(2)/CuSe. An EQCM study showed that, during the initial stage of Cu-Se phase electroformation, water molecules were released from the electrode. In advanced stages of the process, when the electrode was completely covered by Cu-Se compounds, selenide anions were adsorbed on the formed phase. When the anodic potential limit was extended to -0.2 V, copper oxide compounds were formed. The analysis of the cathodic charge related to Cu-Se phase electroreduction and Energy Dispersive X-ray Spectroscopy (EDXS) analysis confirmed that when the anodic limit was -0.8 V, a mixture of different Cu-Se phases was formed. A I/t transient study performed with a bulk copper electrode in alkaline solution containing selenide established that the nucleation and growth mechanism (NGM) of the Cu-Se phases takes place through an initial bidimensional-instantaneous nucleation (IN2D), followed by four bidimensional-progressive nucleations (PN2D). These results and atomic force microscopy (AFM) experiences supported that the growth of the Cu-Se films occurs through a layer-by-layer mechanism. PMID:16851343

Córdova, Ricardo; López, Cristina; Orellana, Marco; Grez, Paula; Schrebler, Ricardo; Del Río, Rodrigo

2005-03-01

105

COPPER DEFICIENCY PROPHYLAXIS IN GRAZING SHEEP BY COPPER OXIDE INJECTION  

E-print Network

COPPER DEFICIENCY PROPHYLAXIS IN GRAZING SHEEP BY COPPER OXIDE INJECTION M. LAMAND Claudine LAB R of insoluble and non ionized form of injected copper has been shown in a previous paper (Lamand, 1978 it appeared that copper oxide was preferable to metallic copper, being slightly less caustic. Inflammation

Boyer, Edmond

106

HEALTH MATTERS Copper T IUD  

E-print Network

HEALTH MATTERS Copper T IUD What is the Copper T IUD? The Copper T IUD is one of two types of intrauterine devices available in the United States. The Copper T IUD is a small, flexible device made of soft plastic and copper. It is easily and quickly inserted into the uterus by a health care provider to prevent

Yener, Aylin

107

Synthesis, crystal growth and characterization of phosphides, selenides, sulfides and oxides  

NASA Astrophysics Data System (ADS)

The desire to build smaller, faster, inexpensive electronics has prompted researchers to exploit electron "spin" in transistors. Spin in semiconductors offers a pathway towards integration of storage and processing in a single material. These "spintronic" transistors could be highly energy-efficient and perform more computations than traditional transistors in a smaller space. In addition, in optoelectronic applications, lasers and light-emitting diodes that take advantage of electron spin could increase the data-carrying capacity of light. But one of the key hurdles in this emerging field is that the magnetic and semiconducting materials needed to make a spintronic device are notoriously incompatible. We have focused on different oxides, phosphides and sulfides to study crystal growth and properties of spintronics. We have reported the synthesis of pure ZnO and Mn substituted ZnO crystals from sodium hydroxide and potassium hydroxide flux for the first time. Various oxides, including boron oxide (B2O3), vanadium oxide (V2O5), tungsten oxide (WO3) and molybdenum oxide (MoO3), were also used for crystal growth. A non-uniform distribution of Mn substitution was found in ZnO single crystals, and 3 at.% Mn concentration was identified. In addition, polycrystalline Mn-substituted ZnO powder samples exhibited solubility of Mn in the ZnO lattice. SQUID magnetic properties investigation of Mn-substituted polycrystalline samples indicated paramagnetism down to 5 K. We have also investigated phosphides, selenides, and sulfides for spintronic applications, based on the well-studied spintronic material, gallium arsenide (GaAs), with a Curie temperature of 110K. GaAs has the zincblende structure with Ga in tetrahedral coordination. ZnSiP2, CdSiP2, KGaS 2 and KGaSe2 have metal atoms in tetrahedral coordination with no localized spin. Localized spin will be present if transition metals are substituted in. The synthesis of single phase ZnSiP2 and CdSiP 2 were grown from two different heat treatments. Also, potassium gallium selenide (KGaSe2) and potassium gallium sulfide (KGaS2) were reported. Temperature dependence susceptibility data revealed a ferromagnetic transition near 300 K followed by an antiferromagnetic transition near 50 K. Hysteresis loops at room temperature were present in all Mn substituted samples. Magnetic properties of Mn substituted samples are comparable with the crystalline MnP sample; they remain unidentified in X-ray diffraction data.

Feng, Chun-Min

108

COPPER RESEARCH UPDATE  

EPA Science Inventory

This presentation provides an update and overview of new research results and remaining research needs with respect to copper corrosion control issues. The topics to be covered include: occurrence of elevated copper release in systems that meet the Action Level; impact of water c...

109

SERUM COPPER IN ALZHEIMER  

Microsoft Academic Search

Abnormalities in the homeostasis of brain metals in Alzheimer's disease (AD) can contribute to set up environmental conditions where ß-amyloid toxicity and deposition are promoted within areas at risk. Recent studies in man have described possible implications of copper in the AD pathogenesis. In particular, evidence collected in our laboratory in the past six years shows that abnormalities in copper

R. SQUITTI; P. M. ROSSINI

2007-01-01

110

Growth of zinc selenide single crystals by physical vapor transport in microgravity  

NASA Technical Reports Server (NTRS)

The goals of this research were the optimization of growth parameters for large (20 mm diameter and length) zinc selenide single crystals with low structural defect density, and the development of a 3-D numerical model for the transport rates to be expected in physical vapor transport under a given set of thermal and geometrical boundary conditions, in order to provide guidance for an advantageous conduct of the growth experiments. In the crystal growth studies, it was decided to exclusively apply the Effusive Ampoule PVT technique (EAPVT) to the growth of ZnSe. In this technique, the accumulation of transport-limiting gaseous components at the growing crystal is suppressed by continuous effusion to vacuum of part of the vapor contents. This is achieved through calibrated leaks in one of the ground joints of the ampoule. Regarding the PVT transport rates, a 3-D spectral code was modified. After introduction of the proper boundary conditions and subroutines for the composition-dependent transport properties, the code reproduced the experimentally determined transport rates for the two cases with strongest convective flux contributions to within the experimental and numerical error.

Rosenberger, Franz

1993-01-01

111

Development of bismuth tellurium selenide nanoparticles for thermoelectric applications via a chemical synthetic process  

SciTech Connect

Research highlights: {yields} We synthesized a Bi{sub 2}Te{sub y}Se{sub 3-y} nano-compound via a chemical synthetic process. {yields} The compound was sintered to achieve an average grain size of about 300 nm. {yields} The resulting sintered body showed very low thermal conductivity. It is likely caused by the vigorous phonon scattering of the nano-sized grains. -- Abstract: Bismuth tellurium selenide (Bi{sub 2}Te{sub y}Se{sub 3-y}) nanoparticles for thermoelectric applications are successfully prepared via a water-based chemical reaction under atmospheric conditions. The nanostructured compound is prepared using a complexing agent (ethylenediaminetetraacetic acid) and a reducing agent (ascorbic acid) to stabilize the bismuth precursor (Bi(NO{sub 3}){sub 3}) in water and to favor the reaction with reduced sources of tellurium and selenium. The resulting powder is smaller than ca. 100 nm and has a crystalline structure corresponding to the rhombohedral Bi{sub 2}Te{sub 2.7}Se{sub 0.3}. The nanocrystalline powder is sintered via a spark plasma sintering process to obtain a sintered body composed of nano-sized grains. Important transport properties of the sintered body are measured to calculate its most important characteristic, the thermoelectric performance. The results demonstrate a relationship between the nanostructure of the sintered body and its thermal conductivity.

Kim, Cham [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of) [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of); Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja-dong, Pohang 790-784 (Korea, Republic of); Kim, Dong Hwan; Han, Yoon Soo [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of)] [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of); Chung, Jong Shik [Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja-dong, Pohang 790-784 (Korea, Republic of)] [Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja-dong, Pohang 790-784 (Korea, Republic of); Park, SangHa [Daegu Machinery Institute of Components and Materials (DMI), 12 Horim-dong, Dalseo-gu, Daegu 704-240 (Korea, Republic of)] [Daegu Machinery Institute of Components and Materials (DMI), 12 Horim-dong, Dalseo-gu, Daegu 704-240 (Korea, Republic of); Park, Soonheum [Department of Nanomaterial Chemistry, Dongguk University, Seokjang-dong, Gyeongju, Gyeongbuk 780-714 (Korea, Republic of)] [Department of Nanomaterial Chemistry, Dongguk University, Seokjang-dong, Gyeongju, Gyeongbuk 780-714 (Korea, Republic of); Kim, Hoyoung, E-mail: hoykim@dgist.ac.kr [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of)] [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of)

2011-03-15

112

Topological insulator bismuth selenide as a theranostic platform for simultaneous cancer imaging and therapy  

NASA Astrophysics Data System (ADS)

Employing theranostic nanoparticles, which combine both therapeutic and diagnostic capabilities in one dose, has promise to propel the biomedical field toward personalized medicine. Here we investigate the theranostic properties of topological insulator bismuth selenide (Bi2Se3) in in vivo and in vitro system for the first time. We show that Bi2Se3 nanoplates can absorb near-infrared (NIR) laser light and effectively convert laser energy into heat. Such photothermal conversion property may be due to the unique physical properties of topological insulators. Furthermore, localized and irreversible photothermal ablation of tumors in the mouse model is successfully achieved by using Bi2Se3 nanoplates and NIR laser irradiation. In addition, we also demonstrate that Bi2Se3 nanoplates exhibit strong X-ray attenuation and can be utilized for enhanced X-ray computed tomography imaging of tumor tissue in vivo. This study highlights Bi2Se3 nanoplates could serve as a promising platform for cancer diagnosis and therapy.

Li, Juan; Jiang, Fei; Yang, Bo; Song, Xiao-Rong; Liu, Yan; Yang, Huang-Hao; Cao, Dai-Rong; Shi, Wen-Rong; Chen, Guo-Nan

2013-06-01

113

Ultrafast Charge- and Energy-Transfer Dynamics in Conjugated Polymer: Cadmium Selenide Nanocrystal Blends  

PubMed Central

Hybrid nanocrystal–polymer systems are promising candidates for photovoltaic applications, but the processes controlling charge generation are poorly understood. Here, we disentangle the energy- and charge-transfer processes occurring in a model system based on blends of cadmium selenide nanocrystals (CdSe-NC) with poly[2-methoxy-5-(3?,7?-dimethyloctyloxy)-1,4-phenylene vinylene] (MDMO-PPV) using a combination of time-resolved absorption and luminescence measurements. The use of different capping ligands (n-butylamine, oleic acid) as well as thermal annealing allows tuning of the polymer–nanocrystal interaction. We demonstrate that energy transfer from MDMO-PPV to CdSe-NCs is the dominant exciton quenching mechanism in nonannealed blends and occurs on ultrafast time scales (<1 ps). Upon thermal annealing electron transfer becomes competitive with energy transfer, with a transfer rate of 800 fs independent of the choice of the ligand. Interestingly, we find hole transfer to be much less efficient than electron transfer and to extend over several nanoseconds. Our results emphasize the importance of tuning the organic–nanocrystal interaction to achieve efficient charge separation and highlight the unfavorable hole-transfer dynamics in these blends. PMID:24490650

2014-01-01

114

Topological insulator bismuth selenide as a theranostic platform for simultaneous cancer imaging and therapy  

PubMed Central

Employing theranostic nanoparticles, which combine both therapeutic and diagnostic capabilities in one dose, has promise to propel the biomedical field toward personalized medicine. Here we investigate the theranostic properties of topological insulator bismuth selenide (Bi2Se3) in in vivo and in vitro system for the first time. We show that Bi2Se3 nanoplates can absorb near-infrared (NIR) laser light and effectively convert laser energy into heat. Such photothermal conversion property may be due to the unique physical properties of topological insulators. Furthermore, localized and irreversible photothermal ablation of tumors in the mouse model is successfully achieved by using Bi2Se3 nanoplates and NIR laser irradiation. In addition, we also demonstrate that Bi2Se3 nanoplates exhibit strong X-ray attenuation and can be utilized for enhanced X-ray computed tomography imaging of tumor tissue in vivo. This study highlights Bi2Se3 nanoplates could serve as a promising platform for cancer diagnosis and therapy. PMID:23770650

Li, Juan; Jiang, Fei; Yang, Bo; Song, Xiao-Rong; Liu, Yan; Yang, Huang-Hao; Cao, Dai-Rong; Shi, Wen-Rong; Chen, Guo-Nan

2013-01-01

115

Structural and optical characterizations of chemically deposited cadmium selenide thin films  

SciTech Connect

Highlights: {yields} CdSe thin films deposited first time using formic acid as a complexing agent. {yields} The deposited thin films were characterized by XRD, SEM, UV-vis-NIR and electrical techniques. {yields} X-ray diffraction analysis shows presence of zinc blende crystal structure. -- Abstract: Synthesis of cadmium selenide thin films by CBD method has been presented. The deposited film samples were subjected to XRD, SEM, UV-vis-NIR and TEP characterization. X-ray diffraction analysis showed that CdSe film sample crystallized in zinc blende or cubic phase structure. SEM studies reveal that the grains are spherical in shape and uniformly distributed all over the surface of the substrates. The optical band gap energy of as deposited film sample was found to be in the order of 1.8 eV. The electrical conductivity of the film sample was found to be 10{sup -6} ({Omega} cm){sup -1} with n-type of conduction mechanism.

Khomane, A.S., E-mail: ashok_khomane@rediffmail.com [Department of Chemistry, Government Rajaram College, S. U. Road, Vidyanagar, Kolhapur 416 004, Maharashtra (India)

2011-10-15

116

Ultrafast charge- and energy-transfer dynamics in conjugated polymer: cadmium selenide nanocrystal blends.  

PubMed

Hybrid nanocrystal-polymer systems are promising candidates for photovoltaic applications, but the processes controlling charge generation are poorly understood. Here, we disentangle the energy- and charge-transfer processes occurring in a model system based on blends of cadmium selenide nanocrystals (CdSe-NC) with poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene] (MDMO-PPV) using a combination of time-resolved absorption and luminescence measurements. The use of different capping ligands (n-butylamine, oleic acid) as well as thermal annealing allows tuning of the polymer-nanocrystal interaction. We demonstrate that energy transfer from MDMO-PPV to CdSe-NCs is the dominant exciton quenching mechanism in nonannealed blends and occurs on ultrafast time scales (<1 ps). Upon thermal annealing electron transfer becomes competitive with energy transfer, with a transfer rate of 800 fs independent of the choice of the ligand. Interestingly, we find hole transfer to be much less efficient than electron transfer and to extend over several nanoseconds. Our results emphasize the importance of tuning the organic-nanocrystal interaction to achieve efficient charge separation and highlight the unfavorable hole-transfer dynamics in these blends. PMID:24490650

Morgenstern, Frederik S F; Rao, Akshay; Böhm, Marcus L; Kist, René J P; Vaynzof, Yana; Greenham, Neil C

2014-02-25

117

Band gap engineering of zinc selenide thin films through alloying with cadmium telluride.  

PubMed

This work investigates band gap engineering of zinc selenide (ZnSe) thin films. This was achieved by mixing ZnSe with cadmium telluride (CdTe). The mass ratio (x) of CdTe in the starting material was varied in the range x = 0-0.333. The films were prepared using thermal evaporation. The chemical composition of the films was investigated through energy dispersive spectroscopy and Rutherford backscattering spectrometry. Structural analysis was carried out using X-ray diffraction and atomic force microscopy. Normal incidence transmittance and reflectance were measured over the wavelength range 300-1300 nm. The absorption coefficients and band gaps were determined from these spectrophotometric measurements. The band gap monotonically decreased from 2.58 eV (for x = 0) to 1.75 eV (for x = 0.333). Photocurrent measurements indicated that the maximum current density was obtained for films with x = 0.286. A figure of merit, based on crystallinity, band gap, and photocurrent, was defined. The optimum characteristics were obtained for the films with x = 0.231, for which the band gap was 2.14 eV. PMID:23688048

Al-Kuhaili, M F; Kayani, A; Durrani, S M A; Bakhtiari, I A; Haider, M B

2013-06-12

118

Memory functions of nanocrystalline cadmium selenide embedded ZrHfO high-k dielectric stack  

SciTech Connect

Metal-oxide-semiconductor capacitors made of the nanocrystalline cadmium selenide nc-CdSe embedded Zr-doped HfO{sub 2} high-k stack on the p-type silicon wafer have been fabricated and studied for their charge trapping, detrapping, and retention characteristics. Both holes and electrons can be trapped to the nanocrystal-embedded dielectric stack depending on the polarity of the applied gate voltage. With the same magnitude of applied gate voltage, the sample can trap more holes than electrons. A small amount of holes are loosely trapped at the nc-CdSe/high-k interface and the remaining holes are strongly trapped to the bulk nanocrystalline CdSe site. Charges trapped to the nanocrystals caused the Coulomb blockade effect in the leakage current vs. voltage curve, which is not observed in the control sample. The addition of the nanocrystals to the dielectric film changed the defect density and the physical thickness, which are reflected on the leakage current and the breakdown voltage. More than half of the originally trapped holes can be retained in the embedded nanocrystals for more than 10 yr. The nanocrystalline CdSe embedded high-k stack is a useful gate dielectric for this nonvolatile memory device.

Lin, Chi-Chou; Kuo, Yue [Thin Film Nano and Microelectronics Research Laboratory, Artie McFerrin Department of Chemical Engineering, Texas A and M University, College Station, Texas 77843-3122 (United States)

2014-02-28

119

Efficient solution-processed small molecule: Cadmium selenide quantum dot bulk heterojunction solar cells  

NASA Astrophysics Data System (ADS)

We report bulk heterojunction solar cells based on blends of solution-processed small molecule [7,7'-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b']dithiophene-2,6-diyl)bis(6-fluoro-4-(5'-hexyl-[2,2'-bithiophen]-5yl)benzo[c] [1,2,5] thiadiazole)] p-DTS(FBTTh2)2: Cadmium Selenide (CdSe) (70:30, 60:40, 50:50, and 40:60) in the device configuration: Indium Tin Oxide /poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/p-DTS(FBTTh2)2: CdSe/Ca/Al. The optimized ratio of p-DTS(FBTTh2)2:CdSe::60:40 leads to a short circuit current density (Jsc) = 5.45 mA/cm2, open circuit voltage (Voc) = 0.727 V, and fill factor (FF) = 51%, and a power conversion efficiency = 2.02% at 100 mW/cm2 under AM1.5G illumination. The Jsc and FF are sensitive to the ratio of p-DTS(FBTTh2)2:CdSe, which is a crucial factor for the device performance.

Gupta, Vinay; Upreti, Tanvi; Chand, Suresh

2013-12-01

120

Intracellular copper routing: the role of copper chaperones.  

PubMed

Copper is required by all living systems. Cells have a variety of mechanisms to deal with this essential, yet toxic trace element. A recently discovered facet of homeostatic mechanisms is the protein-mediated, intracellular delivery of copper to target proteins. This routing is accomplished by a novel class of proteins, the 'copper chaperones'. They are a family of conserved proteins present in prokaryotes and eukaryotes, which suggests that copper chaperones are used throughout nature for intracellular copper routing. PMID:10637610

Harrison, M D; Jones, C E; Solioz, M; Dameron, C T

2000-01-01

121

Copper tolerance in Silene cucubalus  

Microsoft Academic Search

The uptake, translocation and subcellular distribution of copper as well as its effect on chloroplasts and plastocyanin synthesis were studied in a copper-sensitive and a copper-tolerant population of Silene cucubalus (L.) Wib. As a function of time, the copper concentration in roots of tolerant plants increased more slowly than that in roots of sensitive ones. Translocation to the shoot occurred

P. C. Lolkema; R. Vooijs

1986-01-01

122

COPPER CABLE RECYCLING TECHNOLOGY  

SciTech Connect

The United States Department of Energy (DOE) continually seeks safer and more cost-effective technologies for use in deactivation and decommissioning (D&D) of nuclear facilities. The Deactivation and Decommissioning Focus Area (DDFA) of the DOE's Office of Science and Technology (OST) sponsors large-scale demonstration and deployment projects (LSDDPs). At these LSDDPs, developers and vendors of improved or innovative technologies showcase products that are potentially beneficial to the DOE's projects and to others in the D&D community. Benefits sought include decreased health and safety risks to personnel and the environment, increased productivity, and decreased costs of operation. The Idaho National Engineering and Environmental Laboratory (INEEL) generated a list of statements defining specific needs and problems where improved technology could be incorporated into ongoing D&D tasks. One such need is to reduce the volume of waste copper wire and cable generated by D&D. Deactivation and decommissioning activities of nuclear facilities generates hundreds of tons of contaminated copper cable, which are sent to radioactive waste disposal sites. The Copper Cable Recycling Technology separates the clean copper from contaminated insulation and dust materials in these cables. The recovered copper can then be reclaimed and, more importantly, landfill disposal volumes can be reduced. The existing baseline technology for disposing radioactively contaminated cables is to package the cables in wooden storage boxes and dispose of the cables in radioactive waste disposal sites. The Copper Cable Recycling Technology is applicable to facility decommissioning projects at many Department of Energy (DOE) nuclear facilities and commercial nuclear power plants undergoing decommissioning activities. The INEEL Copper Cable Recycling Technology Demonstration investigated the effectiveness and efficiency to recycle 13.5 tons of copper cable. To determine the effectiveness of separating out radioactive contamination, the copper cable was coated with a surrogate contaminant. The demonstration took place at the Bonneville County Technology Center in Idaho Falls, Idaho.

Chelsea Hubbard

2001-05-01

123

Redox control of GPx catalytic activity through mediating self-assembly of Fmoc-phenylalanine selenide into switchable supramolecular architectures.  

PubMed

Artificial enzymes capable of achieving tunable catalytic activity through stimuli control of enzymatic structure transition are of significance in biosensor and biomedicine research. Herein we report a novel smart glutathione peroxidise (GPx) mimic with modulatory catalytic activity based on redox-induced supramolecular self-assembly. First, an amphiphilic Fmoc-phenylalanine-based selenide was designed and synthesized, which can self-assemble into nanospheres (NSs) in aqueous solution. The NSs demonstrate extremely low GPx activity. Upon the oxidation of hydroperoxides (ROOH), the selenide can be quickly transformed into the selenoxide form. The change of the molecular structure induces complete morphology transition of the self-assemblies from NSs to nanotubes (NTs), resulting in great enhancement in the GPx catalytic activity. Under the reduction of GSH, the selenoxide can be further reversibly reduced back into the selenide; therefore the reversible switch between the NSs and NTs can be successfully accomplished. The relationship between the catalytic activity and enzymatic structure was also investigated. The dual response nature makes this mimic play roles of both a sensor and a GPx enzyme at the same time, which can auto-detect the signal of ROOH and then auto-change its activity to achieve quick or slow/no scavenging of ROOH. The dynamic balance of ROOH is vital in organisms, in which an appropriate amount of ROOH does benefit to the metabolism, whereas surplus ROOH can cause oxidative damage of the cell instead and this smart mimic is of remarkable significance. We expect that such a mimic can be developed into an effective antioxidant drug and provide a new platform for the construction of intelligent artificial enzymes with multiple desirable properties. PMID:25366375

Huang, Zupeng; Luo, Quan; Guan, Shuwen; Gao, Jianxiong; Wang, Yongguo; Zhang, Bo; Wang, Liang; Xu, Jiayun; Dong, Zeyuan; Liu, Junqiu

2014-12-28

124

Phase selection and site-selective distribution by tin and sulfur in supertetrahedral zinc gallium selenides.  

PubMed

Doping is among the most important methods to tune the properties of semiconductors. For dense phase semiconductors, the distribution of dopant atoms in crystal lattices is often random. However, when the size of semiconductors becomes increasingly smaller and reaches the extreme situation as is the case in chalcogenide supertetrahedral clusters, different chemically distinct sites (e.g., corner, edge, face, and core) occur, which can dramatically affect the doping chemistry at different sites and also spatial assembly of such clusters into covalent superlattices. In this work, we use the Zn-Ga-Se supertetrahedral clusters and their frameworks as the model system to examine the doping chemistry of Sn(4+) and S(2-) in the Zn-Ga-Se clusters. A series of selenide clusters (undoped supertetrahedral T4-ZnGaSe, S-doped T4-ZnGaSeS, Sn-doped T4-ZnGaSnSe, and dual S- and Sn-doped T4-ZnGaSnSeS) have been prepared with various levels of Sn- and S-doping and with different superlattice structures (OCF-1, -5, -40, and -42). The complex compositional and structural features of these materials are dictated by the convoluted interplay of three key factors: (1) the overall charge density and size/shape matching between clusters/frameworks and protonated guest amines determine the framework topology and the doping levels of Sn(4+) and S(2-); (2) the site selectivity of Sn(4+) is dictated by the local charge balance surrounding anionic Se/S sites as required by the electrostatic valence sum rule; and (3) the site selectivity and doping levels of sulfur is dictated by the location and amount of Sn based on hard soft acid base (HSAB) principle. The cooperative effect of amine-templating and doping by Sn and/or S leads to a rich chemical system with tunable framework compositions, topologies, and electronic properties. PMID:21595469

Wu, Tao; Bu, Xianhui; Zhao, Xiang; Khazhakyan, Ripsime; Feng, Pingyun

2011-06-22

125

First principles study of electronic and mechanical properties of molybdenum selenide type nanowires  

NASA Astrophysics Data System (ADS)

Using the first-principles plane-wave pseudopotential method within density functional theory, we have systematically investigated structural, electronic, and mechanical properties of M2Y6X6 , Y6X6 ( X=Se,Te,S ; Y=Mo,Cr,W ; and M=Li,Na ) nanowires and bulk phase of M2Y6X6 . We found that not only Mo6X6 , but also transition metal and chalcogen atoms lying in the same columns of Mo and Se can form stable nanowires consisting of staggered triangles of Y3X3 . We have shown that all wires have nonmagnetic ground states in their equilibrium geometry. Furthermore, these structures can be either a metal or semiconductor depending on the type of chalcogen element. All Y6X6 wires with X=Te atom are semiconductors. Mechanical stability, elastic stiffness constants, breaking point, and breaking force of these wires have been calculated in order to investigate the strength of these wires. Ab initio molecular dynamic simulations performed at 500K suggest that overall structure remains unchanged at high temperature. Adsorption of H, O, and transition metal atoms like Cr and Ti on Mo6Se6 have been investigated for possible functionalization. All these elements interact with Mo6Se6 wire forming strong chemisorption bonds, and a permanent magnetic moment is induced upon the adsorption of Cr or Ti atoms. Molybdenum selenide-type nanowires can be alternative for carbon nanotubes, since the crystalline ropes consisting of one type of (M2)Y6X6 structures can be decomposed into individual nanowires by using solvents, and an individual nanowire by itself is either a metal or semiconductor and can be functionalized.

Çak?r, D.; Durgun, E.; Gülseren, O.; Ciraci, S.

2006-12-01

126

Parallel molecular dynamics simulations of pressure-induced structural transformations in cadmium selenide nanocrystals  

NASA Astrophysics Data System (ADS)

Parallel molecular dynamics (MD) simulations are performed to investigate pressure-induced solid-to-solid structural phase transformations in cadmium selenide (CdSe) nanorods. The effects of the size and shape of nanorods on different aspects of structural phase transformations are studied. Simulations are based on interatomic potentials validated extensively by experiments. Simulations range from 105 to 106 atoms. These simulations are enabled by highly scalable algorithms executed on massively parallel Beowulf computing architectures. Pressure-induced structural transformations are studied using a hydrostatic pressure medium simulated by atoms interacting via Lennard-Jones potential. Four single-crystal CdSe nanorods, each 44A in diameter but varying in length, in the range between 44A and 600A, are studied independently in two sets of simulations. The first simulation is the downstroke simulation, where each rod is embedded in the pressure medium and subjected to increasing pressure during which it undergoes a forward transformation from a 4-fold coordinated wurtzite (WZ) crystal structure to a 6-fold coordinated rocksalt (RS) crystal structure. In the second so-called upstroke simulation, the pressure on the rods is decreased and a reverse transformation from 6-fold RS to a 4-fold coordinated phase is observed. The transformation pressure in the forward transformation depends on the nanorod size, with longer rods transforming at lower pressures close to the bulk transformation pressure. Spatially-resolved structural analyses, including pair-distributions, atomic-coordinations and bond-angle distributions, indicate nucleation begins at the surface of nanorods and spreads inward. The transformation results in a single RS domain, in agreement with experiments. The microscopic mechanism for transformation is observed to be the same as for bulk CdSe. A nanorod size dependency is also found in reverse structural transformations, with longer nanorods transforming more readily than smaller ones. Nucleation initiates at the center of the rod and grows outward.

Lee, Nicholas Jabari Ouma

127

Volatility of copper  

SciTech Connect

The relevant aqueous thermodynamics of copper and its oxides are evaluated and summarized with emphasis on solubility, hydrolysis, and complexation. The solubilities of metallic copper, solid cuprous and cupric oxides in steam measured by Pocock and Stewart in 1963 are discussed and the latter data are fitted in the form of established empirical equations and compared to other existing results. No other sources of data were found for the solubility of copper and cupric oxide in steam and even these data are very limited. Discussion of corresponding available solubility data on both oxide phases in liquid water is given. The possible effects of complexing agents are considered. A brief discussion is provided of the role of surface adsorption in determining the fate of dissolved copper in the boiler. 37 refs., 5 figs., 3 tabs.

Palmer, D.A.; Simonson, J.M.; Joyce, D.B.

1996-08-01

128

Copper tolerance and copper accumulation of herbaceous plants colonizing inactive California copper mines  

SciTech Connect

Herbaceous plant species colonizing four copper mine waste sites in northern California were investigated for copper tolerance and copper accumulation. Copper tolerance was found in plant species colonizing soils with high concentrations of soil copper. Seven of the eight plant species tested were found at more than one copper mine. The mines are geographically isolated, which makes dispersal of seeds from one mine to another unlikely. Tolerance has probably evolved independently at each site. The nontolerant field control population of Vulpia microstachya displays significantly higher tolerance to copper at all copper concentration levels tested than the nontolerant Vulpia myrous population, and the degree of copper tolerance attained by V. microstachya at the two copper mines was much greater than that found in V. myrous. It suggests that even in these two closely related species, the innate tolerance in their nontolerant populations may reflect their potential for evolution of copper tolerance and their ability to initially colonize copper mine waste sites. The shoot tissue of the copper mine plants of Arenaria douglasii, Bromous mollis, and V. microstachya accumulated less copper than those plants of the same species from the field control sites when the two were grown in identical conditions in nutrient solution containing copper. The root tissue of these mine plants contain more copper than the roots of the nonmine plants. This result suggests that exclusion of copper from the shoots, in part by immobilization in the roots, may be a feature of copper tolerance. No difference in the tissue copper concentration was detected between tolerant and nontolerant plants of Lotus purshianus, Lupinus bicolor, and Trifolium pratense even though the root tissue had more copper than the leaves.

Kruckeberg, A.L.; Wu, L. (Department of Environmental Horticulture, University of California, Davis (United States))

1992-06-01

129

Phase Diagram of (Li1-xFex)OHFeSe: A Bridge between Iron Selenide and Arsenide Superconductors.  

PubMed

Previous experimental results have shown important differences between iron selenide and arsenide superconductors which seem to suggest that the high-temperature superconductivity in these two subgroups of iron-based families may arise from different electronic ground states. Here we report the complete phase diagram of a newly synthesized superconducting (SC) system, (Li1-xFex)OHFeSe, with a structure similar to that of FeAs-based superconductors. In the non-SC samples, an antiferromagnetic (AFM) spin-density-wave (SDW) transition occurs at ?127 K. This is the first example to demonstrate such an SDW phase in an FeSe-based superconductor system. Transmission electron microscopy shows that a well-known ?5×?5 iron vacancy ordered state, resulting in an AFM order at ?500 K in AyFe2-xSe2 (A = metal ions) superconductor systems, is absent in both non-SC and SC samples, but a unique superstructure with a modulation wave vector q = (1)/2(1,1,0), identical to that seen in the SC phase of KyFe2-xSe2, is dominant in the optimal SC sample (with an SC transition temperature Tc = 40 K). Hence, we conclude that the high-Tc superconductivity in (Li1-xFex)OHFeSe stems from the similarly weak AFM fluctuations as FeAs-based superconductors, suggesting a universal physical picture for both iron selenide and arsenide superconductors. PMID:25532066

Dong, Xiaoli; Zhou, Huaxue; Yang, Huaixin; Yuan, Jie; Jin, Kui; Zhou, Fang; Yuan, Dongna; Wei, Linlin; Li, Jianqi; Wang, Xinqiang; Zhang, Guangming; Zhao, Zhongxian

2015-01-14

130

Reduction of selenate to selenide by sulfate-respiring bacteria: Experiments with cell suspensions and estuarine sediments  

USGS Publications Warehouse

Washed cell suspension of Desulfovibrio desulfuricans subsp. aestuarii were capable of reducing nanomolar levels of selenate to selenide as well as sulfate to sulfide. Reduction of these species was inhibited by 1 mM selenate or tungstate. The addition of 1 mM sulfate decreased the reduction of selenate and enhanced the reduction of sulfate. Increasing concentrations of sulfate inhibited rates of selenate reduction but enhanced sulfate reduction rates. Cell suspensions kept in 1 mM selenate were incapable of reducing either selenate or sulfate when the selenate/sulfate ratio was ???0.02, indicating that irreversible inhibition occurs at high selenate concentrations. Anoxic estuarine sediments having an active flora of sulfate-respiring bacteria were capable of a small amount of selenate reduction when ambient sulfate concentrations were low (<4 mM). These results indicate that sulfate is an inhibitor of the reduction of trace qunatitites of selenate. Therefore, direct reduction of traces of selenate to selenide by sulfate-respiring bacteria in natural environments is constrained by the ambient concentration of sulfate ions. The significance of this observation with regard to the role sediments play in sequestering selenium is discussed.

Zehr, J.P.; Oremland, R.S.

1987-01-01

131

Localization of copper and copper transporters in the human brain.  

PubMed

Disturbances in brain copper result in rare and severe neurological disorders and may play a role in the pathogenesis and progression of multiple neurodegenerative diseases. Our current understanding of mammalian brain copper transport is based on model systems outside the central nervous system and no data are available regarding copper transport systems in the human brain. To address this deficit, we quantified regional copper concentrations and examined the distribution and cellular localization of the copper transport proteins Copper transporter 1, Atox1, ATP7A, and ATP7B in multiple regions of the human brain using inductively coupled plasma-mass spectrometry, Western blot and immunohistochemistry. We identified significant relationships between copper transporter levels and brain copper concentrations, supporting a role for these proteins in copper transport in the human brain. Interestingly, the substantia nigra contained twice as much copper than that in other brain regions, suggesting an important role for copper in this brain region. Furthermore, ATP7A levels were significantly greater in the cerebellum, compared with other brain regions, supporting an important role for ATP7A in cerebellar neuronal health. This study provides novel data regarding copper regulation in the human brain, critical to understand the mechanisms by which brain copper levels can be altered, leading to neurological disease. PMID:23076575

Davies, Katherine M; Hare, Dominic J; Cottam, Veronica; Chen, Nicholas; Hilgers, Leon; Halliday, Glenda; Mercer, Julian F B; Double, Kay L

2013-01-01

132

Soft Chemical Control of Superconductivity in Lithium Iron Selenide Hydroxides Li1-xFex(OH)Fe1-ySe.  

PubMed

Hydrothermal synthesis is described of layered lithium iron selenide hydroxides Li1-xFex(OH)Fe1-ySe (x ? 0.2; 0.02 < y < 0.15) with a wide range of iron site vacancy concentrations in the iron selenide layers. This iron vacancy concentration is revealed as the only significant compositional variable and as the key parameter controlling the crystal structure and the electronic properties. Single crystal X-ray diffraction, neutron powder diffraction, and X-ray absorption spectroscopy measurements are used to demonstrate that superconductivity at temperatures as high as 40 K is observed in the hydrothermally synthesized samples when the iron vacancy concentration is low (y < 0.05) and when the iron oxidation state is reduced slightly below +2, while samples with a higher vacancy concentration and a correspondingly higher iron oxidation state are not superconducting. The importance of combining a low iron oxidation state with a low vacancy concentration in the iron selenide layers is emphasized by the demonstration that reductive postsynthetic lithiation of the samples turns on superconductivity with critical temperatures exceeding 40 K by displacing iron atoms from the Li1-xFex(OH) reservoir layer to fill vacancies in the selenide layer. PMID:25613347

Sun, Hualei; Woodruff, Daniel N; Cassidy, Simon J; Allcroft, Genevieve M; Sedlmaier, Stefan J; Thompson, Amber L; Bingham, Paul A; Forder, Susan D; Cartenet, Simon; Mary, Nicolas; Ramos, Silvia; Foronda, Francesca R; Williams, Benjamin H; Li, Xiaodong; Blundell, Stephen J; Clarke, Simon J

2015-02-16

133

Superconducting Phases in Potassium-Intercalated Iron Selenides Tianping Ying, Xiaolong Chen,* Gang Wang,* Shifeng Jin, Xiaofang Lai, Tingting Zhou, Han Zhang,  

E-print Network

Superconducting Phases in Potassium-Intercalated Iron Selenides Tianping Ying, Xiaolong Chen,* Gang two pure SC phases, KxFe2Se2(NH3)y (x 0.3 and 0.6), determined mainly by potassium concentration.84(1) Ã?. With higher potassium doping, the 44 K phase can be converted into the 30 K phase. NH3 has little

Wang, Wei Hua

134

Ring-closure reactions through intramolecular displacement of the phenylselenonyl group by nitrogen nucleophiles: a new stereospecific synthesis of N-tosyl and N-benzoyl-1,3-oxazolidin-2-ones from beta-hydroxyalkyl phenyl selenides.  

PubMed

A new and convenient method for the stereospecific synthesis of variously substituted 1,3-oxazolidin-2-ones from the easily available beta-hydroxyalkyl phenyl selenides is presented. After transformation into the N-tosyl or N-benzoyl carbamates, the selenides were oxidized to the corresponding selenones. The key step of the process is the ring-closure reaction, which occurs by stereospecific intramolecular nucleophilic substitution of the selenone group by the nitrogen atom of the carbamate. Enantiomerically pure 1,3-oxazolidin-2-one derivatives can be easily prepared by using enantiomerically pure beta-hydroxyalkyl phenyl selenides as starting materials. PMID:15054763

Tiecco, Marcello; Testaferri, Lorenzo; Temperini, Andrea; Bagnoli, Luana; Marini, Francesca; Santi, Claudio

2004-04-01

135

Copper Proteins and Oxygen  

PubMed Central

A comprehensive survey of the interaction of the copper proteins and oxygen is presented including a correlation of structure, function, and other properties of the known copper oxidases and of hemocyanin. The origin of their blue color and the structure of copper complexes and copper proteins are related to the oxidation state of copper ion and relevant electronic transitions probably arising from the formation of charge transfer complexes. The oxygen reactions of hemocyanin, ceruloplasmin, and cytochrome oxidase show half-saturation values far below the other Cu enzymes. The formation of hydrogen peroxide as a reaction product is associated with the presence of one Cu atom per oxidase molecule or catalytic system. Water is the corresponding product of the other Cu oxidases with four or more Cu atoms per molecule, except for monoamine oxidase. Mechanisms for the oxidase action of the two and four electron transfer Cu oxidases and tyrosinase are proposed. These reactions account for the number, the oxidation-reduction potential, and the oxidation state of Cu in the resting enzyme, the cyclical change from Cu(II) to Cu(I), the diatomic nature of O2, the sequence of the oxidation and reduction reactions, and other salient features. The catalytic reactions involved in the oxidation of ascorbic acid by plant ascorbate oxidase, ceruloplasmin, and Cu(II) are compared. Finally the substrate specificity, inhibitory control, and the detailed mechanism of the oxidase activity of ceruloplasmin are summarized. PMID:4285728

Frieden, Earl; Osaki, Shigemasa; Kobayashi, Hiroshi

1965-01-01

136

Preparation of high purity copper fluoride by fluorinating copper hydroxyfluoride  

NASA Technical Reports Server (NTRS)

Copper fluoride containing no more than 50 ppm of any contaminating element was prepared by the fluorination of copper hydroxyfluoride. The impurity content was obtained by spark source mass spectrometry. High purity copper fluoride is needed as a cathode material for high energy density batteries.

King, R. B.; Lundquist, J. R.

1969-01-01

137

Agricultural soils spiked with copper mine wastes and copper concentrate: implications for copper bioavailability and bioaccumulation.  

PubMed

A better understanding of exposure to and effects of copper-rich pollutants in soils is required for accurate environmental risk assessment of copper. A greenhouse experiment was conducted to study copper bioavailability and bioaccumulation in agricultural soils spiked with different types of copper-rich mine solid wastes (copper ore, tailing sand, smelter dust, and smelter slag) and copper concentrate. A copper salt (copper sulfate, CuSO4) that frequently is used to assess soil copper bioavailability and phytotoxicity also was included for comparison. Results showed that smelter dust, tailing sand, and CuSO4 are more likely to be bioavailable and, thus, toxic to plants compared with smelter slag, concentrate, and ore at equivalent total copper concentrations. Differences may be explained by intrinsic differences in copper solubilization from the source materials, but also by their capability to decrease soil pH (confounding effect). The copper toxicity and bioaccumulation in plants also varied according to soil physicochemical characteristics (e.g., pH and total organic carbon) and the available levels of plant nutrients, such as nitrogen, phosphorus, and potassium. Chemistry/mineralogy of mine materials, soil/pore-water chemistry, and plant physiological status thus should be integrated for building adequate models to predict phytotoxicity and environmental risk of copper. PMID:16566155

Ginocchio, Rosanna; Sánchez, Pablo; de la Fuente, Luz María; Camus, Isabel; Bustamante, Elena; Silva, Yasna; Urrestarazu, Paola; Torres, Juan C; Rodríguez, Patricio H

2006-03-01

138

The mineralogy of copper electrorefining  

NASA Astrophysics Data System (ADS)

The impurities in copper anodes occur both in solid solution in the copper metal matrix and in discrete inclusions at the copper grain boundaries. During electrorefining, all the impurities undergo extensive chemical and/or morphological changes. These changes impact significantly on anode passivation, cathode quality, electrolyte purification and, of course, the subsequent recovery of by-products from the anode slimes. Recently, mineralogical studies have been undertaken to characterize the various impurities and elucidate their transformations during copper electrorefining.

Chen, T. T.; Dutrizac, J. E.

1990-08-01

139

High adherence copper plating process  

SciTech Connect

A process is described for applying copper to a substrate of aluminum or steel by electrodeposition and for preparing an aluminum or steel substrate for electrodeposition of copper. Practice of the invention provides good adhesion of the copper layer to the substrate.

Mignardot, H.

1992-12-31

140

Tensile behavior of nanocrystalline copper  

Microsoft Academic Search

High density nanocrystalline copper produced by inert gas condensation was tested in tension. Displacements were measured using foil strain gauges, which greatly improved the accuracy of the strain data. The Young`s modulus of nanocrystalline copper was found to be consistent with that of coarse-grained copper. Total elongations of â 1% were observed in samples with grain sizes less than 50

P. G. Sanders; J. R. Weertman; J. A. Eastman

1995-01-01

141

SOURCES OF COPPER AIR EMISSIONS  

EPA Science Inventory

The report gives results of a study to update estimates of atmospheric emissions of copper and copper compounds in the U.S. Source categories evaluated included: metallic minerals, primary copper smelters, iron and steel making, combustion, municipal incineration, secondary coppe...

142

December 200 Copper Acquisition by  

E-print Network

December 200 Copper Acquisition by Methanotrophic Bacteria 7 Term Paper HS2007 Major. One is soluble in the cytoplasm and the other is bound to the membrane. Since the expression of copper containing pMMO depends on copper availability it is supposed that some methanotrophs have developed

Fischlin, Andreas

143

Type-zero copper proteins  

Microsoft Academic Search

Many proteins contain copper in a range of coordination environments, where it has various biological roles, such as transferring electrons or activating dioxygen. These copper sites can be classified by their function or spectroscopic properties. Those with a single copper atom are either type 1, with an intense absorption band near 600 nm, or type 2, with weak absorption in

Kyle M. Lancaster; Serena DeBeer George; Keiko Yokoyama; John H. Richards; Harry B. Gray

2009-01-01

144

Electrical transport and grain growth in solution-cast, chloride-terminated cadmium selenide nanocrystal thin films.  

PubMed

We report the evolution of electrical transport and grain size during the sintering of thin films spin-cast from soluble phosphine and amine-bound, chloride-terminated cadmium selenide nanocrystals. Sintering of the nanocrystals occurs in three distinct stages as the annealing temperature is increased: (1) reversible desorption of the organic ligands (?150 °C), (2) irreversible particle fusion (200-300 °C), and (3) ripening of the grains to >5 nm domains (>200 °C). Grain growth occurs at 200 °C in films with 8 atom % Cl(-), while films with 3 atom % Cl(-) resist growth until 300 °C. Fused nanocrystalline thin films (grain size = 4.5-5.5 nm) on thermally grown silicon dioxide gate dielectrics produce field-effect transistors with electron mobilities as high as 25 cm(2)/(Vs) and on/off ratios of 10(5) with less than 0.5 V hysteresis in threshold voltage without the addition of indium. PMID:24960255

Norman, Zachariah M; Anderson, Nicholas C; Owen, Jonathan S

2014-07-22

145

Synthesis and characterization of the layered iron-selenide Na0.8Fe1.6Se2  

NASA Astrophysics Data System (ADS)

An iron-selenide Na0.8Fe1.6Se2 single crystal has been successfully synthesized using a self-flux method. The electrical resistivity measurement shows that this material exhibits semiconducting behavior in the whole temperature range, with an anomalous increment of resistivity at Ts˜595 K. By varying the concentrations of Na and Fe, a small volume of superconducting phase could be achieved with a critical temperature of Tc˜34 K. Structural characterization shows that, similarly to K0.8Fe1.6Se2 , the Na0.8Fe1.6Se2 phase exhibits clear superstructure with a modulation wave vector of q =(3 /5 ,1 /5 ,0 ) caused by the Fe-vacancy order within the a-b plane.

Long, Y. J.; Wang, D. M.; Wang, Z.; Yang, H. X.; He, J. B.; Zhao, L. X.; Wang, P. P.; Xue, M. Q.; Li, J. Q.; Ren, Z. A.; Chen, G. F.

2014-10-01

146

An approach to global rovibrational analysis based on anharmonic ladder operators: Application to hydrogen selenide and hydrogen sulfide  

NASA Astrophysics Data System (ADS)

A formalism to model the ro-vibrational spectrum of triatomic asymmetric top molecules is presented. The quantum mechanical ro-vibrational kinetic and potential energy function is considered as a Taylor expansion in internal coordinates of Morse local oscillators. Thereafter, local Morse coordinates and momenta are expanded in terms of Morse Potential ladder operators. Only polyad-conserving terms are considered. Expansions of the kinetic and potential energies of the ro-vibrational Hamiltonian are considered up to sextic terms. The resulting Hamiltonian was diagonalized using a symmetry-adapted basis, generated by the eigenfunction method ( J.Q.Chen, Group Representation Theory for Physicists,World Scientific, 1989; R. Lemus, 2003 Mol.Phys., 101 2511-2528.). The model is applied to hydrogen sulfide (H_2S) and hydrogen selenide (H_2Se).

Perez-Bernal, F.; Carvajal, M.; Alvarez-Bajo, O.

2011-05-01

147

Fate of copper in ponds.  

PubMed

Treatments of 3 ppm copper sulfate (CuSO4-5H2O) were applied to two small aquatic systems in Michigan in 1971. To study the pathways of the added copper, samples of water, sediment, aquatic macrophytes, filamentous algae, and fish were collected and analyzed by atomic absorption. Sampling was initiated before treatment and continued up to 4 months in one of the ponds. Dissolved copper concentrations in water decreased rapidly immediately after treatment and then gradually to background levels. Reduction of dissolved copper may have involved initial precipitation of an insoluble compound, such as malachite, followed by sediment adsorption of soluble copper complexes and copper released from aquatic plants. Levels of copper in sediment increased rapidly at first and gradually later in the study. Aquatic plants and filamentous algae accumulated very high levels of copper. Uptake rates were apparently affected by water temperature and growth stages of the plants. Data indicate that aquatic macrophytes developing in one pond 10 weeks after treatment took up copper from the sediment. Although green sunfish (Lepomis cyanellus) accumulated copper soon after treatment, levels returned to background later in the study. PMID:1161446

McIntosh, A W

1975-03-01

148

Copper intercalation into graphite  

NASA Astrophysics Data System (ADS)

An electric brush is necessary for an electric motor to function. The purpose of this thesis is to propose a technique to improve electric brush properties in an effort to produce a more proficient electric motor by creating a new brush material with improved properties and performance. There are many applications for electric motors and each application would benefit from overall, increased proficiency. Understanding the role an electric brush plays within an electric motor is crucial to improving functionality. The proposed technique to create a novel graphite-copper material involves a two-step procedure that will intercalate CuCl2 into the graphite structure, and then by chemical reduction, will reduce the CuCl2 and result in the final products of copper and graphite. The proposed technique seeks to successfully increase the conductivity and wear properties of an electric brush by incorporating copper into graphite which will also enhance the properties of an electric motor. This thesis will detail the procedures of data collection and how to analyze results of the proposed technique. Expected results will also be discussed utilizing preliminary data collected utilizing XRD, SEM, TGA, and BET equipment. Finally, struggles and challenges of such a technique will also be discussed as well as plans for future work on the proposed technique.

Kalbus, Kyle

149

Investigation of deep level defects in epitaxial semiconducting zinc sulpho-selenide. Progress report, 15 June 1979-14 June 1980  

SciTech Connect

In an effort to understand the defect structure of the ternary II-VI compound zinc sulpho-selenide, the binary compound zinc selenide was investigated. Thin single crystalline films of zinc selenide were heteroepitaxially grown on (100) GaAs. Epitaxial layers from 5 to 50 microns thick could be readily grown using a chemical vapor transport technique. The layers had an excellent morphology with few stacking faults and hillocks. Detailed epitaxial growth kinetics were examined as a function of temperature and reactant concentration. It was found that hydrogen flow rate, source and substrate temperature affect the growth rate of the epitaxial films. Au - ZnSe Schottky barrier diodes and ZnSe - GaAs n-p heterojunctions were prepared from the epitaxial layers. Current-voltage characteristics were measured on both types of diodes. From capacitance-voltage measurements the residual doping density of the epitaxial layers were found to be of the order of 10/sup 14/ - 10/sup 15/ cm/sup -3/. Finally, we have begun to measure the deep level spectrum of both the Schottky barrier diodes and the heterojunctions. Deep level transient spectroscopy appears to be well suited for determining trapping states in ZnSe provided the material has a low enough resistivity.

Wessels, B.W.

1980-01-01

150

Copper homeostasis in the CNS  

Microsoft Academic Search

Copper is an essential nutrient that plays a fundamental role in the biochemistry of the central nervous system, as evidenced\\u000a by patients with Menkes disease, a fatal neurodegenerative disorder of childhood resulting from the loss-of-function of a\\u000a copper-transporting P-type adenosine triphosphatase (ATPase). Despite clinical and experimental data indicating a role for\\u000a copper in brain function, the mechanisms and timing of

Michelle L. Schlief; Jonathan D. Gitlin

2006-01-01

151

Removal of copper from ferrous scrap  

DOEpatents

A process for removing copper from ferrous or other metal scrap in which the scrap is contacted with a polyvalent metal sulfide slag in the presence of an excess of copper-sulfide forming additive to convert the copper to copper sulfide which is extracted into the slag to provide a ratio of copper in the slag to copper in the metal scrap of at least about 10.

Blander, M.; Sinha, S.N.

1987-07-30

152

Affinity gradients drive copper to cellular destinations.  

PubMed

Copper is an essential trace element for eukaryotes and most prokaryotes. However, intracellular free copper must be strictly limited because of its toxic side effects. Complex systems for copper trafficking evolved to satisfy cellular requirements while minimizing toxicity. The factors driving the copper transfer between protein partners along cellular copper routes are, however, not fully rationalized. Until now, inconsistent, scattered and incomparable data on the copper-binding affinities of copper proteins have been reported. Here we determine, through a unified electrospray ionization mass spectrometry (ESI-MS)-based strategy, in an environment that mimics the cellular redox milieu, the apparent Cu(I)-binding affinities for a representative set of intracellular copper proteins involved in enzymatic redox catalysis, in copper trafficking to and within various cellular compartments, and in copper storage. The resulting thermodynamic data show that copper is drawn to the enzymes that require it by passing from one copper protein site to another, exploiting gradients of increasing copper-binding affinity. This result complements the finding that fast copper-transfer pathways require metal-mediated protein-protein interactions and therefore protein-protein specific recognition. Together with Cu,Zn-SOD1, metallothioneins have the highest affinity for copper(I), and may play special roles in the regulation of cellular copper distribution; however, for kinetic reasons they cannot demetallate copper enzymes. Our study provides the thermodynamic basis for the kinetic processes that lead to the distribution of cellular copper. PMID:20463663

Banci, Lucia; Bertini, Ivano; Ciofi-Baffoni, Simone; Kozyreva, Tatiana; Zovo, Kairit; Palumaa, Peep

2010-06-01

153

Lead and Copper Control 101  

EPA Science Inventory

This presentation is an overview of the most important water treatment strategies for the control of lead and copper release from drinking water corrosion. In addition to the sections specifically on lead and copper treatment, sections are included that cover sampling to find le...

154

Diagnosis of Copper Transport Disorders  

PubMed Central

Techniques for the diagnosis of copper transport disorders are increasingly important due to recent recognition of previously unappreciated clinical phenotypes and emerging advances in the treatment of these conditions. Here, we collate the diagnostic approaches and techniques currently employed for biochemical and molecular assessment of at-risk individuals in whom abnormal copper metabolism is suspected. PMID:21735378

Møller, Lisbeth B.; Hicks, Julia D.; Holmes, Courtney S.; Goldstein, David S.; Brendl, Cornelia; Huppke, Peter; Kaler, Stephen G.

2011-01-01

155

Copper: from neurotransmission to neuroproteostasis  

PubMed Central

Copper is critical for the Central Nervous System (CNS) development and function. In particular, different studies have shown the effect of copper at brain synapses, where it inhibits Long Term Potentation (LTP) and receptor pharmacology. Paradoxically, according to recent studies copper is required for a normal LTP response. Copper is released at the synaptic cleft, where it blocks glutamate receptors, which explain its blocking effects on excitatory neurotransmission. Our results indicate that copper also enhances neurotransmission through the accumulation of PSD95 protein, which increase the levels of ?-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors located at the plasma membrane of the post-synaptic density. Thus, our findings represent a novel mechanism for the action of copper, which may have implications for the neurophysiology and neuropathology of the CNS. These data indicate that synaptic configuration is sensitive to transient changes in transition metal homeostasis. Our results suggest that copper increases GluA1 subunit levels of the AMPA receptor through the anchorage of AMPA receptors to the plasma membrane as a result of PSD-95 accumulation. Here, we will review the role of copper on neurotransmission of CNS neurons. In addition, we will discuss the potential mechanisms by which copper could modulate neuronal proteostasis (“neuroproteostasis”) in the CNS with focus in the Ubiquitin Proteasome System (UPS), which is particularly relevant to neurological disorders such as Alzheimer’s disease (AD) where copper and protein dyshomeostasis may contribute to neurodegeneration. An understanding of these mechanisms may ultimately lead to the development of novel therapeutic approaches to control metal and synaptic alterations observed in AD patients. PMID:25071552

Opazo, Carlos M.; Greenough, Mark A.; Bush, Ashley I.

2014-01-01

156

A new mixed group 5 metal selenide, Nb1.41V0.59Se9  

PubMed Central

The new mixed-metallic phase, niobium vanadium nona­selenide, (Nb2-xVx)Se9 (0.18? x ? 0.59) is isostructural with monoclinic V2Se9. The structure is composed of chains of bicapped trigonal–prismatic [MSe8] units. The metal (M) site is occupied by statistically disordered Nb [0.706?(5)] and V [0.294?(5)] atoms. Two trigonal prisms are linked by sharing a recta­ngular face composed of two Se2 2? pairs. Through three edging and capping Se atoms, the chains are extended along [101]. The chain shows alternating short [2.8847?(7)?Å] and long [3.7159?(7)?Å] M—M distances. The structure shows a wide range of Se—Se inter­actions. In addition to the Se2 2? pairs of the recta­ngular face, an inter­mediate Se?Se separation [2.6584?(5)?Å] is found. The amount of each metal can vary, [(Nb2-xVx)Se9, 0.18 ? x ?m 0.59] and they seem to form a random substitutional solid solution. The M—M distances increase gradually by increasing the amount of Nb atoms. The classical charge-balance of the compound can be described as [M 4+]2[Se2 2?]2[Se5 4?]. PMID:22064790

Lee, Eunsil; Yun, Hoseop

2011-01-01

157

Effect of an iodine-containing additive on the composition, structure, and morphology of chemically deposited lead selenide films  

NASA Astrophysics Data System (ADS)

The effect of an ammonium iodide additive on the elemental and phase compositions, structural parameters, and surface morphology of lead selenide films synthesized by chemical deposition from aqueous solutions has been studied using X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray analysis. It has been established that the obtained PbSe films have a multiphase structure. The iodine content of the films is directly proportional to the NH4I concentration in the reaction mixture and increases linearly with an increase in this concentration to 0.25 mol/L. No individual iodine-containing phases have been detected in the film structure. However, the introduction of iodine leads to an increase in the PbSe phase lattice parameter from ˜6.11 to ˜6.16 Å and to a decrease in the crystal grain size to ˜ 20 nm. It has been found that there is a correlation between the grain size, lattice parameter, and ammonium iodide concentration in the reaction mixture, which can be explained by changes in the film growth mechanism at the initial growth steps.

Smirnova, Z. I.; Bakanov, V. M.; Maskaeva, L. N.; Markov, V. F.; Voronin, V. I.

2014-12-01

158

Facile hot-injection synthesis of stoichiometric Cu2ZnSnSe4 nanocrystals using bis(triethylsilyl) selenide.  

PubMed

Cu2ZnSnSe4 is a prospective material as an absorber in thin film solar cells due to its many advantages including direct band gap, high absorption coefficient, low toxicity, and relative abundance (indium-free) of its elements. In this report, CZTSe nanoparticles have been synthesized by the hot-injection method using bis-(triethylsilyl)selenide [(Et3Si)2Se] as the selenium source for the first time. Energy dispersive X-ray spectroscopy (EDS) confirmed the stoichiometry of CZTSe nanoparticles. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies showed that the nanocrystals were single phase polycrystalline with their size within the range of 25-30 nm. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy measurements ruled out the existence of secondary phases such as Cu2SnSe3 and ZnSe. The effect of reaction time and precursor injection order on the formation of stoichiometric CZTSe nanoparticles has been studied by Raman spectroscopy. UV-vis-NIR data indicate that the CZTSe nanocrystals have an optical band gap of 1.59 eV, which is optimal for photovoltaic applications. PMID:24823944

Jin, Chunyu; Ramasamy, Parthiban; Kim, Jinkwon

2014-07-01

159

Electric double-layer transistor using layered iron selenide Mott insulator TlFe1.6Se2  

PubMed Central

A1–xFe2–ySe2 (A = K, Cs, Rb, Tl) are recently discovered iron-based superconductors with critical temperatures (Tc) ranging up to 32 K. Their parent phases have unique properties compared with other iron-based superconductors; e.g., their crystal structures include ordered Fe vacancies, their normal states are antiferromagnetic (AFM) insulating phases, and they have extremely high Néel transition temperatures. However, control of carrier doping into the parent AFM insulators has been difficult due to their intrinsic phase separation. Here, we fabricated an Fe-vacancy-ordered TlFe1.6Se2 insulating epitaxial film with an atomically flat surface and examined its electrostatic carrier doping using an electric double-layer transistor (EDLT) structure with an ionic liquid gate. The positive gate voltage gave a conductance modulation of three orders of magnitude at 25 K, and further induced and manipulated a phase transition; i.e., delocalized carrier generation by electrostatic doping is the origin of the phase transition. This is the first demonstration, to the authors' knowledge, of an EDLT using a Mott insulator iron selenide channel and opens a way to explore high Tc superconductivity in iron-based layered materials, where carrier doping by conventional chemical means is difficult. PMID:24591598

Katase, Takayoshi; Hiramatsu, Hidenori; Kamiya, Toshio; Hosono, Hideo

2014-01-01

160

Electric double-layer transistor using layered iron selenide Mott insulator TlFe1.6Se2.  

PubMed

A(1-x)Fe(2-y)Se2 (A = K, Cs, Rb, Tl) are recently discovered iron-based superconductors with critical temperatures (Tc) ranging up to 32 K. Their parent phases have unique properties compared with other iron-based superconductors; e.g., their crystal structures include ordered Fe vacancies, their normal states are antiferromagnetic (AFM) insulating phases, and they have extremely high Néel transition temperatures. However, control of carrier doping into the parent AFM insulators has been difficult due to their intrinsic phase separation. Here, we fabricated an Fe-vacancy-ordered TlFe1.6Se2 insulating epitaxial film with an atomically flat surface and examined its electrostatic carrier doping using an electric double-layer transistor (EDLT) structure with an ionic liquid gate. The positive gate voltage gave a conductance modulation of three orders of magnitude at 25 K, and further induced and manipulated a phase transition; i.e., delocalized carrier generation by electrostatic doping is the origin of the phase transition. This is the first demonstration, to the authors' knowledge, of an EDLT using a Mott insulator iron selenide channel and opens a way to explore high Tc superconductivity in iron-based layered materials, where carrier doping by conventional chemical means is difficult. PMID:24591598

Katase, Takayoshi; Hiramatsu, Hidenori; Kamiya, Toshio; Hosono, Hideo

2014-03-18

161

Preparation of Few-Layer Bismuth Selenide by Liquid-Phase-Exfoliation and Its Optical Absorption Properties  

PubMed Central

Bismuth selenide (Bi2Se3), a new topological insulator, has attracted much attention in recent years owing to its relatively simple band structure and large bulk band gap. Compared to bulk, few-layer Bi2Se3 is recently considered as a highly promising material. Here, we use a liquid-phase exfoliation method to prepare few-layer Bi2Se3 in N-methyl-2-pyrrolidone or chitosan acetic solution. The resulted few-layer Bi2Se3 dispersion demonstrates an interesting absorption in the visible light region, which is different from bulk Bi2Se3 without any absorption in this region. The absorption spectrum of few-layer Bi2Se3 depends on its size and layer number. At the same time, the nonlinear and saturable absorption of few-layer Bi2Se3 thin film in near infrared is also characterized well and further exploited to generate laser pulses by a passive Q-switching technique. Stable Q-switched operation is achieved with a lower pump threshold of 9.3?mW at 974?nm, pulse energy of 39.8?nJ and a wide range of pulse-repetition-rate from 6.2 to 40.1?kHz. Therefore, the few-layer Bi2Se3 may excite a potential applications in laser photonics and optoelectronic devices. PMID:24762534

Sun, Liping; Lin, Zhiqin; Peng, Jian; Weng, Jian; Huang, Yizhong; Luo, Zhengqian

2014-01-01

162

Preparation of Few-Layer Bismuth Selenide by Liquid-Phase-Exfoliation and Its Optical Absorption Properties  

NASA Astrophysics Data System (ADS)

Bismuth selenide (Bi2Se3), a new topological insulator, has attracted much attention in recent years owing to its relatively simple band structure and large bulk band gap. Compared to bulk, few-layer Bi2Se3 is recently considered as a highly promising material. Here, we use a liquid-phase exfoliation method to prepare few-layer Bi2Se3 in N-methyl-2-pyrrolidone or chitosan acetic solution. The resulted few-layer Bi2Se3 dispersion demonstrates an interesting absorption in the visible light region, which is different from bulk Bi2Se3 without any absorption in this region. The absorption spectrum of few-layer Bi2Se3 depends on its size and layer number. At the same time, the nonlinear and saturable absorption of few-layer Bi2Se3 thin film in near infrared is also characterized well and further exploited to generate laser pulses by a passive Q-switching technique. Stable Q-switched operation is achieved with a lower pump threshold of 9.3 mW at 974 nm, pulse energy of 39.8 nJ and a wide range of pulse-repetition-rate from 6.2 to 40.1 kHz. Therefore, the few-layer Bi2Se3 may excite a potential applications in laser photonics and optoelectronic devices.

Sun, Liping; Lin, Zhiqin; Peng, Jian; Weng, Jian; Huang, Yizhong; Luo, Zhengqian

2014-04-01

163

Thermo-optical effect in zinc selenide windows for two-color interferometer for fusion plasma diagnostics  

SciTech Connect

After some improvements in the two-color interferometer for plasma density measurements in the TJII fusion device, an effect, which we attribute to the thermo-optical characteristics of zinc selenide windows, has been put in evidence. Part of the 53.2 GHz mm radiation, used to heat the plasma, heats the windows and produces an optical path length difference between the two laser beams of 10.6 and 0.633 {mu}m wavelength. The effect induces a deformation of the line integral density measured by the interferometer. It is important in shots with high plasma reflectivity at the electron cyclotron resonance heating (ECRH) frequency. Some experiments and calculations have been done. The effect is explained and its order of magnitude is justified on the basis of some approximations. Several ways to avoid the effect including a correction procedure are discussed. Other possible heating sources are also discussed. The observed effect could be very relevant for experiments where ECRH is the main heating mechanism.

Sanchez, Miguel; Sanchez, Joaquin [Dena Laser S.L., 28035 Madrid (Spain); Asociacion EURATOM/CIEMAT, 28040 Madrid (Spain)

2005-04-01

164

Solvothermal synthesis, deposition and characterization of cadmium selenide (CdSe) thin films by thermal evaporation technique  

NASA Astrophysics Data System (ADS)

Nanocrystalline compound semiconductor Cadmium Selenide was synthesized by the solvothermal method using Cd(NO 3) 2.4H 2O and Se metal granules. The synthesized nanocrystalline CdSe particles were subjected to vacuum annealing at 450 °C to maintain the hexagonal phase. The as synthesized and annealed powders were analyzed using XRD, SEM, EDX and DTA. The X-ray diffraction pattern of the as synthesized powder shows cubic phase, whereas the 450 °C annealed CdSe powder exhibits hexagonal phase. The annealed nanocrystalline CdSe was pelletized using hydraulic pressure of 5 ton and used to deposit thin films at different substrate temperature like Room Temperature (RT), 150, 250, 350 and 450 °C by thermal evaporation using glass as substrate. The deposited films were subjected to XRD, SEM, EDX, UV-vis, Photoluminescence, Raman Spectroscopy and Hall Effect measurement to study their properties. The thickness of the films was measured with thickness profilometer. The thermally deposited CdSe films exhibit the hexagonal structure with n-type conductivity.

Shyju, T. S.; Anandhi, S.; Indirajith, R.; Gopalakrishnan, R.

2011-12-01

165

Investigation of reaction mechanisms of bismuth tellurium selenide nanomaterials for simple reaction manipulation causing effective adjustment of thermoelectric properties.  

PubMed

We synthesized ternary n-type bismuth tellurium selenide nanomaterials for thermoelectric applications via a water-based chemical reaction under an atmospheric environment. In this work, bismuth nitrate was employed as a bismuth precursor and was hydrolyzed to form bismuth hydroxide in an aqueous solution. Ascorbic acid was used to dissolve the bismuth hydroxide and give a reactive bismuth source (Bi(3+) ions) that was able to react with anion sources (Te(2-)/Se(2-) ions). Ascorbic acid played a role in reducing bismuth hydroxide to an unreactive bismuth source (bismuth particles, Bi(0)). We confirmed that ascorbic acid dissolved or reduced bismuth hydroxide depending on the solution pH. Because either Bi(3+) ions or bismuth particles were generated depending on the pH, the nanomaterial stoichiometry was pH dependent. Nanomaterials prepared at various pH levels were individually sintered using a spark plasma sintering process to measure their thermoelectric transport properties (i.e., carrier concentration, electrical resistivity, Seebeck coefficient, and thermal conductivity). We observed how the transport properties were affected through adjustment of the pH of the reaction and found an appropriate pH for optimizing the transport properties, which resulted in enhancement of the thermoelectric performance. PMID:24372342

Kim, Cham; Kim, Dong Hwan; Kim, Jong Tae; Han, Yoon Soo; Kim, Hoyoung

2014-01-22

166

Regulation of extracellular copper-binding proteins in copper-resistant and copper-sensitive mutants of Vibrio alginolyticus.  

PubMed Central

Extracellular proteins of wild-type Vibrio alginolyticus were compared with those of copper-resistant and copper-sensitive mutants. One copper-resistant mutant (Cu40B3) constitutively produced an extracellular protein with the same apparent molecular mass (21 kDa) and chromatographic behavior as copper-binding protein (CuBP), a copper-induced supernatant protein which has been implicated in copper detoxification in wild-type V. alginolyticus. Copper-sensitive V. alginolyticus mutants displayed a range of alterations in supernatant protein profiles. CuBP was not detected in supernatants of one copper-sensitive mutant after cultures had been stressed with 50 microM copper. Increased resistance to copper was not induced by preincubation with subinhibitory levels of copper in the wild type or in the copper-resistant mutant Cu40B3. Copper-resistant mutants maintained the ability to grow on copper-amended agar after 10 or more subcultures on nonselective agar, demonstrating the stability of the phenotype. A derivative of Cu40B3 with wild-type sensitivity to copper which no longer constitutively expressed CuBP was isolated. The simultaneous loss of both constitutive CuBP production and copper resistance in Cu40B3 indicates that constitutive CuBP production is necessary for copper resistance in this mutant. These data support the hypothesis that the extracellular, ca. 20-kDa protein(s) of V. alginolyticus is an important factor in survival and growth of the organism at elevated copper concentrations. The range of phenotypes observed in copper-resistant and copper-sensitive V. alginolyticus indicate that altered sensitivity to copper was mediated by a variety of physiological changes. Images PMID:8031076

Harwood, V J; Gordon, A S

1994-01-01

167

Porphyry-copper mineralisation in the central Srednogorie zone, Bulgaria  

NASA Astrophysics Data System (ADS)

The porphyry-copper systems in the central part of the Srednogorie zone (Bulgaria) are represented by three major deposits (Elatsite, Medet and Assarel) and several smaller deposits and occurrences, all of them within the Panagyurishte ore district. The hydrothermal systems are related to Late Cretaceous calc-alkaline igneous complexes. Ore mineralisation is developed predominantly in the apical parts of subvolcanic and intrusive bodies as well as within the volcanic and basement metamorphic rocks. Several of the porphyry systems are spatially associated with shallow-level intermediate and high-sulphidation volcanic-hosted epithermal deposits of economic importance, such as the major gold-copper mine at Chelopech located 10 km from the Elatsite porphyry-copper deposit. Mineralisation processes in the porphyry deposits start with intensive hydrothermal alteration of the wall rocks. K-silicate alteration is characteristic for pre-ore hydrothermal activity in all of them, and it is located mostly in their central parts. Propylitic alteration is prominent in the Medet and Assarel deposits. The Assarel deposit is located in the central part of a palaeovolcanic structure and shows a large spectrum of pre-ore alterations, including propylitic, sericitic, and advanced argillic assemblages. The initial stages of the hydrothermal systems are characterised by high temperatures (>550-500 °C) and highly saline (50-20 wt% NaCl equiv.) and vapour-rich fluids of likely magmatic origin. The composition of the fluids gradually changes from H2O-NaCl±FeCl2 to H2O-NaCl-KCl and H2O-NaCl-dominated as the fluids cool, react with wall rocks, and may become diluted with meteoric water. Fe-Ti-oxide mineral associations were formed early in all deposits, later followed, in the Elatsite deposit, by an assemblage of bornite, chalcopyrite, platinum group element (PGE) phases, Co-Ni thiospinels, Ag- and Bi-tellurides, and selenides. The main ore stage in all deposits is dominated by chalcopyrite ± pyrite, associated with propylitic alteration at Medet, K-silcate-sericite alteration at Elatsite, and chlorite-sericite alteration at Assarel. Specific geochemical features of the ore systems are marked by precipitation of numerous fine-grained mineral inclusions in chalcopyrite and pyrite (palladoarsenide, Pd-rammelsbergite, Cu-Ni sulpharsenides in Elatsite; Co-and Ni-pyrite, carrolite, vaesite, sulvanite and colusite in Medet; enargite, As-sulvanite, colusite, goldfieldite, wittichenite, calaverite and aikinite in Assarel). Native gold and electrum are observed as small grains, except in Elatsite where larger aggregates up to several millimetres are found. Molybdenite is present as small flakes within chalcopyrite, or forms felted aggregates within thin quartz veinlets in the Elatsite and Medet deposits, and very rarely at Assarel. Thin veinlets of quartz-galena-sphalerite are found at the upper parts of the deposits. Supergene alteration of the primary sulphide minerals is developed in the Assarel deposit where a thick blanket of secondary copper mineralisation (chalcocite, covellite) has formed. In the other two deposits, secondary mineral associations (Cu and Fe oxides and hydroxides) are limited to near the surface. Differences in the deposits studied suggest that Elatsite and Medet are formed probably at deeper levels of the porphyry systems, whereas Assarel is developed at rather shallower and lower-temperature conditions typical of the apical part of a subvolcanic body intruding its volcanic superstructure.

Strashimirov, Strashimir; Petrunov, Rumen; Kanazirski, Milko

2002-08-01

168

The Role of Copper in Tumour Angiogenesis  

Microsoft Academic Search

Copper stimulates the proliferation and migration of endothelial cells and is required for the secretion of several angiogenic factors by tumour cells. Copper chelation decreases the secretion of many of these factors. Serum copper levels are upregulated in many human tumours and correlate with tumour burden and prognosis. Copper chelators reduce tumour growth and microvascular density in animal models. New

Sarah A. Lowndes; Adrian L. Harris

2005-01-01

169

[The copper IUD and gonococcus].  

PubMed

The sensitivity of 66 gonococcus strains isolated from 35 men and 31 women suffering purulent secretion from the urethra was tested in vitro by determination of the inhibition zone to 3 antibiotics and to pure copper. Inhibition of gonococcus growth by copper were also studied in vivo in 15 women with positive cultures following the insertion of an IUD with pure copper. Observations following IUD insertion were very promising and gave completely negative results of the culture and the direct specimen in all but 1 case in which the disease had been localized in the cervical mucus. (author's) PMID:12311953

Mantouvalos, H; Metallinos, C; Gouskos, A

1983-01-01

170

The SLC31 (Ctr) copper transporter family  

Microsoft Academic Search

Copper is essential for many copper-dependent processes, including mitochondrial oxidative phosphorylation, free-radical detoxification, pigmentation, neurotransmitter synthesis, and iron metabolism. The identification of proteins for high affinity copper uptake and export has greatly expanded our understanding of cellular copper homeostasis. Copper export in human cells is mediated by the ATP7A and ATP7B P-type ATPases, which are, respectively, affected in the genetic

Michael J. Petris

2004-01-01

171

First direct discrimination of chiral phosphine selenide (P=Se) derivatives by multinuclear magnetic resonance spectroscopy in the presence of a chiral dirhodium complex.  

PubMed

Enantiomeric ratios of compounds with P=Se functionalities (phosphine selenides) can easily be determined by (1)H, (13)C, (31)P, and (77)Se NMR spectroscopic inspection of their diastereomeric complexes with (R)-Rh(2)(MTPA)(4) (MTPA-H identical with methoxytrifluoromethylphenylacetic acid; Mosher's acid). This is the first facile and rapid spectroscopic method for chiral recognition in this class of compounds. Whereas most complexation shifts Delta(delta) are moderate or even negligible, significant signal dispersions Delta(nu) can be observed. Some rationalization for the adduct formation mode is presented. NMR spectral characteristics of the free P=Se compounds 1-5 are described. PMID:11984756

Malik, Shahid; Duddeck, Helmut; Omelanczuk, Jan; Choudhary, Muhammad Iqbal

2002-05-15

172

Genome Sequences of Two Copper-Resistant Escherichia coli Strains Isolated from Copper-Fed Pigs  

PubMed Central

The draft genome sequences of two copper-resistant Escherichia coli strains were determined. These had been isolated from copper-fed pigs and contained additional putative operons conferring copper and other metal and metalloid resistances. PMID:25540351

Lüthje, Freja L.; Hasman, Henrik; Aarestrup, Frank M.; Alwathnani, Hend A.

2014-01-01

173

Synthesis, crystal structure and electronic properties of the new iron selenide Ba9Fe4Se16  

NASA Astrophysics Data System (ADS)

The new ternary selenide Ba9Fe4Se16 has been synthesized from the reaction of appropriate amounts of elements at high temperature in a silica sealed tube. The compound crystallizes in the tetragonal space group I41/a with a=10.0068(3) Å and c=35.6415(9) Å, Z=4. It is an isostructural compound to the sulfide ?-Ba9Fe4S15, which is a high temperature polymorph of ?-Ba9Fe4Se15 that belongs to the indefinitely adaptive phases series Ba3Fe1+xS5, 0?x?1. X-ray powder diffraction and TEM analyses of the synthesized compound were used to determine the phase composition and the structure. The crystal structure can be viewed as overlapping sections along the c axis. Those sections are formed by the coordination polyhedra around barium atoms which can be described as trigonal prisms and bidisphenoids. Within the sections formed by barium polyhedra, isolated pairs of edge sharing FeSe4 tetrahedra are found. Magnetic measurements performed on Ba9Fe4Se16 indicate an antiferromagnetic behavior with Néel temperature of ~13 K. Possible influence of air exposure on the magnetic properties is also discussed here. The electric measurements show an insulating behavior below 160 K and the dielectric permittivity and loss tangent at the lowest frequency measured reveal a change of slope very close to TN. However no magneto dielectric effect was evidenced for magnetic fields of up to 3 T. Activation energy, EA=0.18 eV, was extracted from the AC conductivity plot in the temperature range of 160-300 K.

Berthebaud, David; Preethi Meher, K. R. S.; Pelloquin, Denis; Maignan, Antoine

2014-03-01

174

The presence of mercury selenide in various tissues of the striped dolphin: evidence from ?-XRF-XRD and XAFS analyses.  

PubMed

Marine mammals accumulate mercury in their tissues at high concentration and detoxify by forming mercury selenide (HgSe, tiemannite) mainly in the liver. We investigated the possibility of formation of HgSe in various tissues (liver, kidney, lung, spleen, pancreas, muscle and brain) other than the liver of the striped dolphin (Stenella coeruleoalba). We applied a combination method of micro-X-ray fluorescence (?-XRF) imaging and micro-X-ray diffraction (?-XRD) using a synchrotron radiation X-ray microbeam to analyze the tissue samples directly with minimal sample preparation. By this method, many accumulation points for Hg and Se on a micron scale were found in thin sections of the spleen and liver tissue and consequently, the XRF spectra and the XRD pattern of the hot spots confirmed the presence of tiemannite, HgSe. On the other hand, the insoluble fractions after enzyme digestion of the nuclear and mitochondrial fractions of all tissues were subjected to X-ray absorption fine structure (XAFS) analysis. XAFS analysis confirmed the presence of HgSe in all the tissues examined (liver, kidney, lung, spleen, pancreas, muscle and brain) of the striped dolphin. The presence of HgSe in all the tissues examined suggests that Se would be involved in the detoxification process of Hg in various tissues other than the liver. This contribution seems to be large especially in the liver and spleen but relatively small in the kidney, pancreas and brain, because the proportion of insoluble fraction containing HgSe was lower in these tissues (25 to 46%). This is the first report on the presence of tiemannite HgSe in various tissues of marine mammals. PMID:21468440

Nakazawa, Emiko; Ikemoto, Tokutaka; Hokura, Akiko; Terada, Yasuko; Kunito, Takashi; Tanabe, Shinsuke; Nakai, Izumi

2011-07-01

175

Copper enzyme activities in cystic fibrosis before and after copper supplementation plus or minus zinc.  

PubMed

One laboratory reports low activities for 2 blood copper enzymes in subjects with cystic fibrosis (CF), which suggests that moderate copper deficiency is common in this state. The present study attempted to confirm this proposition in 3 ways: repeat the measures for 1 of the 2 copper enzymes (superoxide dismutase) in a new group of CF patients (males and females, N = 38), add another copper enzyme measure (plasma diamine oxidase) that has high sensitivity to copper status, and test if copper enzyme activities in CF patients rise by copper supplementation. The last test was performed plus or minus zinc supplementation since poor zinc status may contribute to poor copper status. The results for the first 2 aims supported the idea of poor copper status, as low activities were found for CF subjects for 2 copper enzyme activities, erythrocyte superoxide dismutase and plasma diamine oxidase (although normal activities were obtained for another copper enzyme, plasma ceruloplasmin, both as U/mL plasma or U/mg ceruloplasmin immunoreactive protein). For the last aim, copper enzyme activities were not altered by copper supplementation (6 weeks, 3 mg copper/d as copper-glycinate), plus or minus concurrent zinc supplementation (30 mg zinc/d as zinc-glycinate). Therefore, CF may cause a tendency to moderate copper deficiency, which may be due to abnormal copper metabolism not easily corrected by increased copper and/or zinc intake. PMID:14681839

Best, Kristin; McCoy, Karen; Gemma, Susan; Disilvestro, Robert A

2004-01-01

176

BTA copper complexes.  

PubMed

Cupric oxide is one of the most important additives used (a) to catalyze decomposition reactions in gas generators to obtain cooler reaction gases, (b) as burning enhancer for ammonium perchlorate-based composite propellants, and (c) as coloring agent in pyrotechnics. In this context, the reaction of Cu(2+) ions in aqueous ammonia solution with bis(tetrazolyl)amine (H(2)bta) was investigated. Depending on the reaction conditions three complexes were obtained: Cu(bta)(NH(3))(2) (1), Cu(bta)(NH(3))(2).H(2)O (2), and (NH(4))(2)Cu(bta)(2).2.5H(2)O (3). The crystal structures of 1 and 2 are discussed with respect to the coordination mode of the dianion of N,N-bis(1(2)H-tetrazol-5-yl)-amine (bta), which mediates in the case of 1 and 2 weak superexchange interactions between the adjacent magnetic transition-metal Cu(II) cations. These antiferromagnetic interactions result from 1D copper chains over an hidden azide end-to-end bridge. Interestingly, the structural arrangement of 1 completely changes in the presence of crystal-bound water. Moreover, some physicochemical properties (e.g., heat of formation, friction, and impact sensitivity, DSC) of these complexes with respect to high-energetic materials are discussed. PMID:16241154

Friedrich, Manfred; Gálvez-Ruiz, Juan Carlos; Klapötke, Thomas M; Mayer, Peter; Weber, Birgit; Weigand, Jan J

2005-10-31

177

Spray pyrolysis of tin selenide thin-film semiconductors: the effect of selenium concentration on the properties of the thin films  

NASA Astrophysics Data System (ADS)

Thin films of tin selenide (SnxSey) with an atomic ratio of , 1 and 1.5 were prepared on a glass substrate at T = 470°C using a spray pyrolysis technique. The initial materials for the preparation of the thin films were an alcoholic solution consisting of tin chloride (SnCl4· 5H2O) and selenide acide (H2SeO3). The prepared thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy, scanning tunneling microscopy, scanning helium ion microscopy, and UV-vis spectroscopy. The photoconductivity and thermoelectric effects of the SnxSey thin films were then studied. The SnxSey thin films had a polycrystalline structure with an almost uniform surface and cluster type growth. The increasing atomic ratio of r in the films, the optical gap, photosensitivity and Seebeck coefficient were changed from 1.6 to 1.37 eV, 0.01 to 0.31 and -26.2 to -42.7 mV/K (at T = 350 K), respectively. In addition, the XRD patterns indicated intensity peaks in r = 1 that corresponded to the increase in the SnSe and SnSe2 phases.

Fadavieslam, M. R.; Bagheri-Mohagheghi, M. M.

2013-08-01

178

Luminescence and generation of laser radiation in zinc selenide and cadmium sulfide single crystals exposed to high-voltage subnanosecond pulses  

NASA Astrophysics Data System (ADS)

The action of high-voltage subnanosecond pulses on AIIBVI semiconductor compounds is studied. A negative pulse with a duration of up to 500 ps is applied to electrodes of a special shape. The pulse amplitude can be varied from 20 to 250 kV. Plane-parallel plates with a thickness of 1-2 mm made of bulk zinc selenide or cadmium sulfide single crystals are placed between the electrodes. Experiments are carried out in air without submerging single crystal plates in a liquid dielectric medium. As soon as a voltage pulse is applied, diverging discharges propagate from sharp edges of the negative electrode along electric field lines. With increasing voltage, generation of laser radiation is observed in the bulk of the semiconductor, displaying all its characteristic features, such as a sharp increase in the radiation power, narrowing the spectrum, and the radiation directionality. For zinc selenide at room temperature, the radiation characteristics are as follows: the wavelength is 480 nm, the radiation divergence is about 3°, and the peak pulse power is 600 W.

Mesyats, G. A.; Nasibov, A. S.; Shpak, V. G.; Shunailov, S. A.; Yalandin, M. I.

2008-06-01

179

Reliability of copper interconnects in integrated circuits  

E-print Network

As dimensions shrink and current densities increase, the reliability of metal interconnects becomes a serious concern. In copper interconnects, the dominant diffusion path is along the interface between the copper and the ...

Choi, Zung-Sun

2007-01-01

180

Molecular Mediators Governing Iron-Copper Interactions  

PubMed Central

Given their similar physiochemical properties, it is a logical postulate that iron and copper metabolism are intertwined. Indeed, iron-copper interactions were first documented over a century ago, but the homeostatic effects of one on the other has not been elucidated at a molecular level to date. Recent experimental work has, however, begun to provide mechanistic insight into how copper influences iron metabolism. During iron deficiency, elevated copper levels are observed in the intestinal mucosa, liver, and blood. Copper accumulation and/or redistribution within enterocytes may influence iron transport, and high hepatic copper may enhance biosynthesis of a circulating ferroxidase, which potentiates iron release from stores. Moreover, emerging evidence has documented direct effects of copper on the expression and activity of the iron-regulatory hormone hepcidin. This review summarizes current experimental work in this field, with a focus on molecular aspects of iron-copper interplay and how these interactions relate to various disease states. PMID:24995690

Gulec, Sukru; Collins, James F.

2015-01-01

181

21 CFR 582.5260 - Copper gluconate.  

Code of Federal Regulations, 2010 CFR

... ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5260 Copper gluconate. (a) Product. Copper gluconate. (b) Tolerance. This...

2010-04-01

182

Mechanical Separation of Metallic Copper from Polymer-Insulated Copper Wire  

Microsoft Academic Search

It is very important to recycling of polymer-insulated copper wire to remove copper from the wire without any contamination. A rolling machine and a blender were used to separate and recover the copper wires from a polymer coated cable. In the experiment using a rolling machine, the recovery of copper was improved by an increase in the number of rolling

Seiji Yokoyama; Sakae Takeuchi; Nik Hisyamudin Bin Muhd Nor

2011-01-01

183

Copper and Anesthesia: Clinical Relevance and Management of Copper Related Disorders  

PubMed Central

Recent research has implicated abnormal copper homeostasis in the underlying pathophysiology of several clinically important disorders, some of which may be encountered by the anesthetist in daily clinical practice. The purpose of this narrative review is to summarize the physiology and pharmacology of copper, the clinical implications of abnormal copper metabolism, and the subsequent influence of altered copper homeostasis on anesthetic management. PMID:23762044

Langley, Adrian; Dameron, Charles T.

2013-01-01

184

Copper-mediated LDL oxidation by homocysteine and related compounds depends largely on copper ligation  

E-print Network

Copper-mediated LDL oxidation by homocysteine and related compounds depends largely on copper of copper-mediated LDL oxidation (initiation, conjugated diene formation and aldehyde formation), whereas at high concentration, it acts as an antioxidant. The affinity for copper of homocysteine and related

Williamson, Mike P.

185

Chemical behavior of the biradicaloid (HO...ONO) singlet states of peroxynitrous acid. The oxidation of hydrocarbons, sulfides, and selenides.  

PubMed

Various high levels of theory have been applied to the characterization of two higher lying biradicaloid metastable singlet states of peroxynitrous acid. A singlet minimum (cis-2) was located that had an elongated O-O distance (2.17 A) and was only 12.2 kcal/mol [UB3LYP/6-311+G(3df,2p)+ZPVE] higher in energy than its ground-state precursor. A trans-metastable singlet (trans-2) was 10.9 kcal/mol higher in energy than ground-state HO-ONO. CASSCF(12,10)/6-311+G(d,p) calculations predict the optimized geometries of these cis- and trans-metastable singlets to be close to those obtained with DFT. Optimization of cis- and trans-2 within the COSMO solvent model suggests that both exist as energy minima in polar media. Both cis- and trans-2 exist as hydrogen bonded complexes with several water molecules. These collective data suggest that solvated forms of cis-2.3H(2)O and trans-2.3H(2)O represent the elusive higher lying biradicaloid minima that were recently (J. Am. Chem. Soc. 2003, 125, 16204) advocated as the metastable forms of peroxynitrous acid (HOONO). The involvement of metastable trans-2 in the gas phase oxidation of methane and isobutane is firmly established to take place on the unrestricted [UB3LYP/6-311+G(d,p)] potential energy surface (PES) with classical activations barriers for the hydrogen abstraction step that are 15.7 and 5.9 kcal/mol lower than the corresponding activation energies for producing products methanol and tert-butyl alcohol formed on the restricted PES. The oxidation of dimethyl sulfide and dimethyl selenide, two-electron oxidations, proceeds by an S(N)2-like attack of the heteroatom lone pair on the O-O bond of ground-state peroxynitrous acid. No involvement of metastable forms of HO-ONO was discernible. PMID:15740154

Bach, Robert D; Dmitrenko, Olga; Estévez, Carlos M

2005-03-01

186

Laser sintering of copper nanoparticles  

NASA Astrophysics Data System (ADS)

Copper nanoparticle (NP) inks serve as an attractive potential replacement to silver NP inks in functional printing applications. However their tendency to rapidly oxidize has so far limited their wider use. In this work we have studied the conditions for laser sintering of Cu-NP inks in ambient conditions while avoiding oxidation. We have determined the regime for stable, low-resistivity copper (< ×3 bulk resistivity value) generation in terms of laser irradiance and exposure duration and have indicated the limits on fast processing. The role of pre-drying conditions on sintering outcome has also been studied. A method, based on spectral reflectivity measurements, was used for non-contact monitoring of the sintering process evolution. It also indicates preferred spectral regions for sintering. Finally, we illustrated how selective laser sintering can generate high-quality, fine line (<5 µm wide) and dense copper circuits.

Zenou, Michael; Ermak, Oleg; Saar, Amir; Kotler, Zvi

2014-01-01

187

Traveling fronts of copper deposition.  

PubMed

We report the experimental observation of traveling fronts during the electroless deposition of copper on passive steel substrates. The low-carbon steel samples are passivated in nitric acid prior to the plating experiment, thus creating a thin, protective oxide layer on the steel surface. The deposition experiments are carried out from slightly acidic (pH 3.2) copper sulfate solution and copper nitrate solution with the latter showing front propagation only in the presence of chloride ions. For up to 30 s, fronts propagate with constant velocities in the range from 0.5 to 5 mm/s depending on the experimental conditions. This phase of constant-speed propagation gives way to accelerating fronts and very rapid, spatially unstructured deposition. Front-mediated plating is observed over a wide range of cupric ion concentration and constitutes a striking and unexpected example for pattern formation in electrochemical systems. PMID:12197727

Thouvenel-Romans, Stephanie; Agladze, Konstantin; Steinbock, Oliver

2002-09-01

188

Copper - HTS hybrid conductor architecture  

NASA Astrophysics Data System (ADS)

Plating of a copper layer using an aqueous copper sulfate electrolytic deposition on the surface of CC is described. The paper focuses on basic electrical and chemical parameters. High concentration copper sulfate solution of 150 - 250 g/l with low content of sulfur acid solution at electrolytic current densities of 30 - 50 mA/cm2 delivers fine grained stable Cu layers. A noble metal (Ag, Au) seed layer improves the deposition speed and the tape surround plating. Pulse plating increases the plating efficiency and is utilized in a developed reel - to - reel plating unit to deposit a Cu shunt on CC continuously. Mixed electrolytic solutions are the electrochemical basis for CuNi and brass deposition. Practical solder joints are obtained using Sn-Pb-Cu standard soldering at temperature of 250 °C A joint resistance of 0.2??cm2 could be obtained routinely in practical CC assembling.

Floegel-Delor, U.; Riedel, T.; Wippich, D.; Goebel, B.; Rothfeld, R.; Werfel, F. N.; Usoskin, A.; Rutt, A.

2010-06-01

189

Application of saccharose as copper(II) ligand for electroless copper plating solutions.  

PubMed

Saccharose, forming sufficiently stable complexes with copper(II) ions in alkaline solutions, was found to be a suitable ligand for copper(II) chelating in alkaline (pH>12) electroless copper deposition solutions. Reduction of copper(II)-saccharose complexes by hydrated formaldehyde was investigated and the copper deposits formed were characterized. The thickness of the compact copper coatings obtained under optimal operating conditions in 1h reaches ca. 2 microm at ambient temperature. The plating solutions were stable and no signs of Cu(II) reduction in the bulk solution were observed. Results were compared with those systems operating with other copper(II) ligands. PMID:17109836

Norkus, Eugenijus; Prusinskas, Kestutis; Vaskelis, Algirdas; Jaciauskiene, Jane; Stalnioniene, Irena; Macalady, Donald L

2007-01-15

190

Textured carbon surfaces on copper by sputtering  

NASA Technical Reports Server (NTRS)

A very thin layer of highly textured carbon is applied to a copper surface by a triode sputtering process. A carbon target and a copper substrate are simultaneously exposed to an argon plasma in a vacuum chamber. The resulting carbon surface is characterized by a dense, random array of needle like spires or peaks which extend perpendicularly from the copper surface. The coated copper is especially useful for electrode plates in multistage depressed collectors.

Curren, A. N. (inventor); Jensen, K. A. (inventor); Roman, R. F. (inventor)

1986-01-01

191

Contribution of Copper Ion Resistance to Survival of Escherichia coli on Metallic Copper Surfaces?  

PubMed Central

Bacterial contamination of touch surfaces poses a serious threat for public health. The use of bactericidal surface materials, such as copper and its alloys, might constitute a way to aid the use of antibiotics and disinfectants, thus minimizing the risk of emergence and spread of multiresistant germs. The survival of Escherichia coli on metallic copper surfaces has been studied previously; however, the mechanisms underlying bacterial inactivation on copper surfaces have not been elucidated. Data presented in this study suggest that bacteria are killed rapidly on dry copper surfaces. Several factors, such as copper ion toxicity, copper chelators, cold, osmotic stress, and reactive oxygen species, but not anaerobiosis, influenced killing rates. Strains deleted in copper detoxification systems were slightly more sensitive than was the wild type. Preadaptation to copper enhanced survival rates upon copper surface exposure. This study constitutes a first step toward understanding the reasons for metallic copper surface-mediated killing of bacteria. PMID:18156321

Santo, Christophe Espírito; Taudte, Nadine; Nies, Dietrich H.; Grass, Gregor

2008-01-01

192

THE EVOLUTION OF SYNTHETICALLY PRECIPITATED COPPER SOLIDS  

EPA Science Inventory

The objective of this study was to explore the effect of water quality, particularly chloride and sulfate, on copper mineral formation. Copper-sulfate and chloride compounds are often found on the surface of copper pipes in drinking water distribution systems. When attempting to ...

193

Copper vs. Copper at the Relativistic Heavy Ion Collider (2005)  

ScienceCinema

To investigate a new form of matter not seen since the Big Bang, scientists are using a new experimental probe: collisions between two beams of copper ions. The use of intermediate size nuclei is expected to result in intermediate energy density - not as

Brookhaven Lab - Fulvia Pilat

2010-01-08

194

The Enterococcus hirae paradigm of copper homeostasis: Copper chaperone turnover, interactions, and transactions  

Microsoft Academic Search

The cop operon is a key element of copper homeostasis in Enterococcus hirae. It encodes two copper ATPases, CopA and CopB, the CopY repressor, and the CopZ metallochaperone. The cop operon is induced by copper, which allows uncompromised growth in up to 5 mM ambient copper. Copper uptake appears to be accomplished by the CopA ATPase, a member of the

Zen Huat Lu; Charles T. Dameron; Marc Solioz

2003-01-01

195

The Enterococcus hirae paradigm of copper homeostasis: Copper chaperone turnover, interactions, and transactions  

Microsoft Academic Search

The cop operon is a key element of copper homeostasis in Enterococcus hirae. It encodes two copper ATPases, CopA and CopB, the CopY repressor, and the CopZ metallochaperone. The cop operon is induced by copper, which allows uncompromised growth in up to 5 mM ambient copper. Copper uptake appears to be accomplished by the CopA ATPase, a member of the heavy

Zen Huat Lu; Charles T. Dameron; Marc Solioz

2003-01-01

196

BotEC: Percentage of Copper in Ore  

NSDL National Science Digital Library

Question Suppose that you are building a new house. It will take about 90 kg (198 pounds) of copper to do the electrical wiring. In order to get the copper in the first place, someone needs to mine solid rock that contains copper, extract the copper minerals, throw away the waste rock, and smelt the copper minerals to produce copper metal. Rocks mined for copper typically contain only very small percentages of copperâabout 0.7% in the case of most of the big porphyry copper deposits of the world. How much rock would someone have to mine in order to extract enough copper to wire your new house?

Tewksbury, Barb

197

Building a Copper Pipe "Xylophone."  

ERIC Educational Resources Information Center

Explains how to use the equation for frequency of vibration of a transversely oscillating bar or pipe with both ends free to vibrate to build a simple and inexpensive xylophone from a 3-meter section of copper pipe. The instrument produces a full major scale and can be used to investigate various musical intervals. (Author/NB)

Lapp, David R.

2003-01-01

198

Michigan's Copper Country in Photographs  

NSDL National Science Digital Library

Copper production has gone on around Michigan's Keweenaw Peninsula for over 3,000 years. Native Americans first engaged in the practice these many millennia ago, and by the 1840s, there were mineral rushes going on in the area. Many thousands of people came in search of copper, and by 1985, over 14 billion pounds of copper were produced from the region. This remarkable digital collection crafted by Michigan Technological University brings together many historical photographs that document the district. All told, there are over 3,500 items here, and visitors can search the holdings by keyword or more detailed parameters. Visitors also have the option of creating their own personal web album with items of interest to them. The Subject Browse tab is a good way to delve into the collection, as visitors can look over anything from Accidents to Woody Plants. This collection illuminates the region and the ways in which the copper industry transformed this rural and bucolic environment.

2008-06-19

199

COPPER CORROSION AND SOLUBILITY RESEARCH  

EPA Science Inventory

This poster provides a very cursory summary of TTEB in-house copper research experimental systems, and extramural research projects. The field studies summarized are the Indian Hill (OH) study of the use of orthophosphate for reducing cuprosolvency in a high alkalinity water, an...

200

Depositing copper patterns on teflon  

SciTech Connect

Printed circuit boards composed of patterned cooper features on poly(tetrafluorethylene), better known by the E.I. du Pont de Nemours and Company trade name Teflon, are currently used for high-frequency applications. The choice of these materials is based on the high conductivity of copper and the facts that Teflon has One of the lowest reported dielectric constants ({approximately}2.0). Low dissipation factors. High thermal stability. High chemical resistance. This paper reports that the high conductivity of copper, coupled with the low dielectric constant of Teflon, allows high-frequency operation and/or extensive miniaturization. However, one of Teflon's most important properties is chemical and physical inertness. While this property is extremely attractive in numerous applications involving hostile environments, it presents major problems in metallization for electronic applications. To address this condition, researchers at Sandia National Laboratories and the University of New Mexico have developed a three-step, additive method for the patterned deposition of copper on Teflon. Still, while the example of deposition work examined in this article is recent, it is nonetheless supported by considerable prior work on the patterned etching of Teflon and copper chemical vapor deposition (CVD).

Rye, R.R. (Sandia National Lab. (US)); Hampden-Smith, M.J.; Kodas, T.T. (Univ. of New Mexico, NM (US))

1992-07-01

201

Copper-mediated dimerization of CopZ, a predicted copper chaperone from Bacillus subtilis.  

PubMed

Understanding the metal-binding properties and solution states of metallo-chaperones is a key step in understanding how they function in metal ion transfer. Using spectroscopic, bioanalytical and biochemical methods, we have investigated the copper-binding properties and association states of the putative copper chaperone of Bacillus subtilis, CopZ, and a variant of the protein lacking the two cysteine residues of the MXCXXC copper-binding motif. We show that copper-free CopZ exists as a monomer, but that addition of copper(I) causes the protein to associate into homodimers. The nature of the copper(I)-CopZ complex is dependent on the level of copper loading, and we report the detection of three distinct forms, containing 0.5, 1.0 and 1.5 copper(I) ions per protein. The presence of excess dithiothreitol has a significant effect on copper(I) binding to CopZ, such that, in its presence, copper(I)-CopZ occurs mainly as a monomer species. Data for copper binding to the double-cysteine variant of CopZ are consistent with an essential role for these residues in tight copper binding in the wild-type protein. We conclude that the complex nature of copper(I) binding to CopZ may underpin mechanisms of protein-to-protein copper(I) transfer. PMID:12238948

Kihlken, Margaret A; Leech, Andrew P; Le Brun, Nick E

2002-12-15

202

A Plasmodium falciparum copper-binding membrane protein with copper transport motifs  

PubMed Central

Background Copper is an essential catalytic co-factor for metabolically important cellular enzymes, such as cytochrome-c oxidase. Eukaryotic cells acquire copper through a copper transport protein and distribute intracellular copper using molecular chaperones. The copper chelator, neocuproine, inhibits Plasmodium falciparum ring-to-trophozoite transition in vitro, indicating a copper requirement for malaria parasite development. How the malaria parasite acquires or secretes copper still remains to be fully elucidated. Methods PlasmoDB was searched for sequences corresponding to candidate P. falciparum copper-requiring proteins. The amino terminal domain of a putative P. falciparum copper transport protein was cloned and expressed as a maltose binding fusion protein. The copper binding ability of this protein was examined. Copper transport protein-specific anti-peptide antibodies were generated in chickens and used to establish native protein localization in P. falciparum parasites by immunofluorescence microscopy. Results Six P. falciparum copper-requiring protein orthologs and a candidate P. falciparum copper transport protein (PF14_0369), containing characteristic copper transport protein features, were identified in PlasmoDB. The recombinant amino terminal domain of the transport protein bound reduced copper in vitro and within Escherichia coli cells during recombinant expression. Immunolocalization studies tracked the copper binding protein translocating from the erythrocyte plasma membrane in early ring stage to a parasite membrane as the parasites developed to schizonts. The protein appears to be a PEXEL-negative membrane protein. Conclusion Plasmodium falciparum parasites express a native protein with copper transporter characteristics that binds copper in vitro. Localization of the protein to the erythrocyte and parasite plasma membranes could provide a mechanism for the delivery of novel anti-malarial compounds. PMID:23190769

2012-01-01

203

Accumulation and hyperaccumulation of copper in plants  

NASA Astrophysics Data System (ADS)

Copper is natural component of our environment. Flow of copper(II) ions in the environment depends on solubility of compounds containing this metal. Mobile ion coming from soil and rocks due to volcanic activity, rains and others are then distributed to water. Bio-availability of copper is substantially lower than its concentration in the aquatic environment. Copper present in the water reacts with other compounds and creates a complex, not available for organisms. The availability of copper varies depending on the environment, but moving around within the range from 5 to 25 % of total copper. Thus copper is stored in the sediments and the rest is transported to the seas and oceans. It is common knowledge that copper is essential element for most living organisms. For this reason this element is actively accumulated in the tissues. The total quantity of copper in soil ranges from 2 to 250 mg / kg, the average concentration is 30 mg / kg. Certain activities related to agriculture (the use of fungicides), possibly with the metallurgical industry and mining, tend to increase the total quantity of copper in the soil. This amount of copper in the soil is a problem particularly for agricultural production of food. The lack of copper causes a decrease in revenue and reduction in quality of production. In Europe, shows the low level of copper in total 18 million hectares of farmland. To remedy this adverse situation is the increasing use of copper fertilizers in agricultural soils. It is known that copper compounds are used in plant protection against various illnesses and pests. Mining of minerals is for the development of human society a key economic activity. An important site where the copper is mined in the Slovakia is nearby Smolníka. Due to long time mining in his area (more than 700 years) there are places with extremely high concentrations of various metals including copper. Besides copper, there are also detected iron, zinc and arsenic. Various plant species have adapted on such stress. The aim of this study is to investigate the behaviour of copper in plants and to assess its potential effect on the surrounding environment. To detect copper in biological samples electrochemical methods were employed particularly differential pulse voltammetry (DPV). Copper gave signals at 0.02 V measured by DPV. The obtained calibration dependence was linear (R2 = 0.995). Further, this method was utilized for determination of copper in real soil samples obtained from previously mentioned heavy-metal-polluted mining area. The content varied within range from tens to hundreds of mg of copper per kg of the soil. Moreover, we focused on investigation of copper influence on seedlings of Norway spruce. The seedlings were treated with copper (0, 0.1, 10 and 100 mM) for four weeks. We observed anatomical-morphological changes and other biochemical parameters in plants. We determined that seedlings synthesized more than 48 % protective thiols (glutathione and phytochelatins) compared to control ones. We investigated copper distribution in plant tissues by diphenylcarbazide staining. We found out that copper is highly accumulated in parenchymal stalk cells. In needles, change in auto-fluorescence of parenchymal cells of mesoderm similarly to endodermis cells. Besides, we analyzed samples of plants from the polluted area (spruce, pin, birch). The data obtained well correlated with previously mentioned. Acknowledgement The work on this experiment was supported by grant: INCHEMBIOL MSM0021622412.

Adam, V.; Trnkova, L.; Huska, D.; Babula, P.; Kizek, R.

2009-04-01

204

Uptake and internalisation of copper by three marine microalgae: comparison of copper-sensitive and copper-tolerant species.  

PubMed

Although it has been well established that different species of marine algae have different sensitivities to metals, our understanding of the physiological and biochemical basis for these differences is limited. This study investigated copper adsorption and internalisation in three algal species with differing sensitivities to copper. The diatom Phaeodactylum tricornutum was particularly sensitive to copper, with a 72-h IC50 (concentration of copper to inhibit growth rate by 50%) of 8.0 microg Cu L(-1), compared to the green algae Tetraselmis sp. (72-h IC50 47 microg Cu L(-1)) and Dunaliella tertiolecta (72-h IC50 530 microg Cu L(-1)). At these IC50 concentrations, Tetraselmis sp. had much higher intracellular copper (1.97+/-0.01 x 10(-13)g Cu cell(-1)) than P. tricornutum (0.23+/-0.19 x 10(-13)g Cu cell(-1)) and D. tertiolecta (0.59+/-0.05 x 10(-13)g Cu cell(-1)), suggesting that Tetraselmis sp. effectively detoxifies copper within the cell. By contrast, at the same external copper concentration (50 microg L(-1)), D. tertiolecta appears to better exclude copper than Tetraselmis sp. by having a slower copper internalisation rate and lower internal copper concentrations at equivalent extracellular concentrations. The results suggest that the use of internal copper concentrations and net uptake rates alone cannot explain differences in species-sensitivity for different algal species. Model prediction of copper toxicity to marine biota and understanding fundamental differences in species-sensitivity will require, not just an understanding of water quality parameters and copper-cell binding, but also further knowledge of cellular detoxification mechanisms. PMID:18639348

Levy, Jacqueline L; Angel, Brad M; Stauber, Jennifer L; Poon, Wing L; Simpson, Stuart L; Cheng, Shuk Han; Jolley, Dianne F

2008-08-29

205

Metallic copper as an antimicrobial surface.  

PubMed

Bacteria, yeasts, and viruses are rapidly killed on metallic copper surfaces, and the term "contact killing" has been coined for this process. While the phenomenon was already known in ancient times, it is currently receiving renewed attention. This is due to the potential use of copper as an antibacterial material in health care settings. Contact killing was observed to take place at a rate of at least 7 to 8 logs per hour, and no live microorganisms were generally recovered from copper surfaces after prolonged incubation. The antimicrobial activity of copper and copper alloys is now well established, and copper has recently been registered at the U.S. Environmental Protection Agency as the first solid antimicrobial material. In several clinical studies, copper has been evaluated for use on touch surfaces, such as door handles, bathroom fixtures, or bed rails, in attempts to curb nosocomial infections. In connection to these new applications of copper, it is important to understand the mechanism of contact killing since it may bear on central issues, such as the possibility of the emergence and spread of resistant organisms, cleaning procedures, and questions of material and object engineering. Recent work has shed light on mechanistic aspects of contact killing. These findings will be reviewed here and juxtaposed with the toxicity mechanisms of ionic copper. The merit of copper as a hygienic material in hospitals and related settings will also be discussed. PMID:21193661

Grass, Gregor; Rensing, Christopher; Solioz, Marc

2011-03-01

206

Copper handling machinery of the brain.  

PubMed

Copper plays an indispensable role in the physiology of the human central nervous system (CNS). As a cofactor of dopamine-?-hydroxylase, peptidyl-?-monooxygenase, superoxide dismutases, and many other enzymes, copper is a critical contributor to catecholamine biosynthesis, activation of neuropeptides and hormones, protection against reactive oxygen species, respiration and other processes essential for normal CNS function. Copper content in the CNS is tightly regulated, and changes in copper levels in the brain are associated with a wide spectrum of pathologies. However, the mechanistic understanding of copper transport in the CNS is still in its infancy. Little is known about copper distribution among various cell types or cell-specific regulation of copper homeostasis, despite the fact that the molecules mediating copper transport and distribution in the brain (CTR1, Atox1, CCS, ScoI/II, ATP7A and ATP7B) have been identified and their importance in CNS function increasingly understood. In this review, we summarize current knowledge about copper levels and uses in the CNS and describe the molecules involved in maintaining copper homeostasis in the brain. PMID:21072351

Lutsenko, Svetlana; Bhattacharjee, Ashima; Hubbard, Ann L

2010-09-01

207

Chronic poisoning by copper in tap water: I. Copper intoxications with predominantly gastointestinal symptoms.  

PubMed

Copper can induce acute and chronic intoxications in humans. Copper in tap water has caused a series of severe systemic diseases in Germany in recent years (copper induced liver cirrhosis). Besides cirrhosis, another type of disease with predominantly gastrointestinal symptoms has occurred which likewise appeared to be induced by copper in tap water. - In a retrospective investigation we looked for additional indications and proof that chronic copper poisoning has been the cause of the observed gastrointestinal diseases. All patients suffering from this type of disease had copper plumbing in their houses. - The patients (children and adults) suffered from nausea, vomiting, colic, and diarrhoea. In the group of infants, one refused formula milk (prepared with tap water) and the others suffered from persistent restlessness, unexplainable screaming (especially at night) and/or long lasting diaper rash. - We accept the diagnosis of chronic copper intoxication as the cause of the gastrointestinal symptoms when at least one of the following criteria were fulfilled: 1. first manifestation, remission and relapse of the disease depend on intake and a non-intake of water containing copper, respectively. 2. hypercupric state of the patients (i.e. pathological high concentrations of the non-ceruloplasmin-bound copper in serum and/or elevated copper levels in urine) 3. signs of systemic copper intoxication in the same patient 4. signs of systemic copper intoxication or hypercupric states in members of the patient s family or in his neighbourhood (non-relatives) - We found that the disease can even be caused by copper concentrations below the allowed concentration given by the German Guidelines for Drinking Water (Trinkwasserverordnung). - The data prove that copper in drinking water can cause gastrointestinal diseases and not only the better known systemic diseases (i.e. copper induced liver cirrhosis). Copper poisoning must be considered as a possible cause of chronic gastrointestinal diseases in those countries in which copper plumbing is common. PMID:10383875

Eife, R; Weiss, M; Barros, V; Sigmund, B; Goriup, U; Komb, D; Wolf, W; Kittel, J; Schramel, P; Reiter, K

1999-06-28

208

The Enterococcus hirae paradigm of copper homeostasis: copper chaperone turnover, interactions, and transactions.  

PubMed

The cop operon is a key element of copper homeostasis in Enterococcus hirae. It encodes two copper ATPases, CopA and CopB, the CopY repressor, and the CopZ metallochaperone. The cop operon is induced by copper, which allows uncompromised growth in up to 5 mM ambient copper. Copper uptake appears to be accomplished by the CopA ATPase, a member of the heavy metal CPx-type ATPases and closely related to the human Menkes and Wilson ATPases. The related CopB ATPase extrudes copper when it reaches toxic levels. Intracellular copper routing is accomplished by the CopZ copper chaperone. Using surface plasmon resonance analysis, it was demonstrated that CopZ interacts with the CopA ATPase where it probably becomes copper loaded. CopZ in turn can donate copper to the copper responsive repressor CopY, thereby releasing it from DNA. In high copper, CopZ is proteolyzed. Cell extracts were found to contain a copper activated proteolytic activity that degrades CopZ in vitro. This post-translational control of CopZ expression presumably serves to avoid the accumulation of detrimental Cu-CopZ levels. PMID:12572673

Lu, Zen Huat; Dameron, Charles T; Solioz, Marc

2003-03-01

209

Evaluation of copper resistant bacteria from vineyard soils and mining waste for copper biosorption  

PubMed Central

Vineyard soils are frequently polluted with high concentrations of copper due application of copper sulfate in order to control fungal diseases. Bioremediation is an efficient process for the treatment of contaminated sites. Efficient copper sorption bacteria can be used for bioremoval of copper from contaminated sites. In this study, a total of 106 copper resistant bacteria were examined for resistance to copper toxicity and biosorption of copper. Eighty isolates (45 from vineyard Mollisol, 35 from Inceptisol) were obtained from EMBRAPA (Empresa Brasileira de Pesquisa Agropecuária) experimental station, Bento Gonçalves, RS, Brazil (29°09?53.92?S and 51°31?39.40?W) and 26 were obtained from copper mining waste from Caçapava do Sul, RS, Brazil (30°29?43.48?S and 53?32?37.87W). Based on resistance to copper toxicity and biosorption, 15 isolates were identified by 16S rRNA gene sequencing. Maximal copper resistance and biosorption at high copper concentration were observed with isolate N2 which removed 80 mg L?1 in 24 h. Contrarily isolate N11 (Bacillus pumilus) displayed the highest specific copper biosorption (121.82 mg/L/OD unit in 24 h). GenBank MEGABLAST analysis revealed that isolate N2 is 99% similar to Staphylococcus pasteuri. Results indicate that several of our isolates have potential use for bioremediation treatment of vineyards soils and mining waste contaminated with high copper concentration. PMID:24031606

Andreazza, R.; Pieniz, S.; Okeke, B.C.; Camargo, F.A.O

2011-01-01

210

Biosorption and bioreduction of copper from different copper compounds in aqueous solution.  

PubMed

High copper concentration is toxic for living organisms including humans. Biosorption is a bioremediation technique that can remove copper and other pollutants from aqueous medium and soils, consequently cleaning the environment. The aim of this study was, therefore, to investigate the influence of different copper compounds (Cu(II) as CuCl2; Cu(II) as CuSO4; and Cu(I) as CuCl) on copper bioreduction and biosorption using four copper-resistant bacteria isolated from the rhizosphere of two plants (Avena sativa and Plantago lanceolata) in aqueous matrix. Copper resistance profile, bioreduction, and biosorption after 48 h of incubation were evaluated. The isolates displayed high copper resistance. However, isolate A1 did not grow very well in the CuCl2 and isolate T5 was less resistant to copper in aqueous solutions amended with CuCl (Cu(I)). The best copper source for copper bioreduction and biosorption was CuSO4 and the isolates removed as much as ten times more copper than in aqueous solutions amended with the other copper compounds. Moreover, Cu(I) did not succumb to biosorption, although the microbes were resistant to aqueous solutions of CuCl. In summary, Cu(II) from CuSO4 was furthermost susceptible to bioreduction and biosorption for all isolates. This is an indication that copper contamination of the environment from the use of CuSO4 as an agrochemical is amenable to bioremediation. PMID:23417495

Andreazza, Robson; Okeke, Benedict C; Pieniz, Simone; Bento, Fátima M; Camargo, Flávio A O

2013-06-01

211

Copper-induced production of copper-binding supernatant proteins by the marine bacterium Vibrio alginolyticus.  

PubMed Central

Growth of the marine bacterium Vibrio alginolyticus is temporarily inhibited by micromolar levels of copper. During the copper-induced lag phase, supernatant compounds which complex and detoxify copper are produced. In this study two copper-inducible supernatant proteins having molecular masses of ca. 21 and 19 kilodaltons (CuBP1 and CuBP2) were identified; these proteins were, respectively, 25 and 46 times amplified in supernatants of copper-challenged cultures compared with controls. Experiments in which chloramphenicol was added to cultures indicated that there was de novo synthesis of these proteins in response to copper. When supernatants were separated by gel permeation chromatography, CuBP1 and CuBP2 coeluted with a copper-induced peak in copper-binding activity. CuBP1 and CuBP2 from whole supernatants were concentrated and partially purified by using a copper-charged immobilized metal ion affinity chromatography column, confirming the affinity of these proteins for copper. A comparison of cell pellets and supernatants demonstrated that CuBP1 was more concentrated in supernatants than in cells. Our data are consistent with a model for a novel mechanism of copper detoxification in which excretion of copper-binding protein is induced by copper. Images PMID:2339887

Harwood-Sears, V; Gordon, A S

1990-01-01

212

Accumulation of Copper and Other Metals by Copper-Resistant Plant-Pathogenic and Saprophytic Pseudomonads  

PubMed Central

Copper-resistant strains of Pseudomonas syringae carrying the cop operon produce periplasmic copper-binding proteins, and this sequestration outside the cytoplasm has been proposed as a resistance mechanism. In this study, strain PS61 of P. syringae carrying the cloned cop operon accumulated more total cellular copper than without the operon. Several other copper-resistant pseudomonads with homology to cop were isolated from plants, and these bacteria also accumulated copper. Two highly resistant species accumulated up to 115 to 120 mg of copper per g (dry weight) of cells. P. putida 08891 was more resistant to several metals than P. syringae pv. tomato PT23, but this increased resistance was not correlated with an increased accumulation of metals other than copper. Several metals were accumulated by both PT23 and P. putida, but when copper was added to induce the cop operon, there was generally no increase of accumulation of the other metals, suggesting that the cop operon does not contribute to accumulation of these other metals. The exceptions were aluminum for PT23 and iron for P. putida, which accumulated to higher levels when copper was added to the cultures. The results of this study support the role of copper sequestration in the copper resistance mechanism of P. syringae and suggest that this mechanism is common to several copper-resistant Pseudomonas species found on plants to which antimicrobial copper compounds are applied for plant disease control. PMID:16348627

Cooksey, Donald A.; Azad, Hamid R.

1992-01-01

213

Copper disinfection ban causes storm.  

PubMed

Since 1 February this year, under the EU's Biocidal Products Directive, it has been illegal to sell or use water treatment systems that use elemental copper, a practice employed historically by a significant number of UK healthcare facilities to combat Legionella. Alan Lester, managing director of specialist supplier of 'environmentally-friendly' water treatment systems, Advanced Hydro, says the ban has caused 'a storm of giant proportion,' with advocates of copper ion-based treatment systems arguing that this disinfection method dates back 3,000 years to Egyptian times, making it an 'undoubtedly proven' technology. Here he explains why the ban came into force, considers why the UK's Health and Safety Executive (HSE) is seeking a derogation, looks at the ban's likely impact, and gives a personal viewpoint on the 'pros and cons' of some of the alternative treatment technologies, including a titanium dioxide-based system marketed by Advanced Hydro itself in the UK. PMID:23763088

Lester, Alan

2013-05-01

214

Fracture and Fatigue Behavior at Ambient and Elevated Temperatures of Alumina Bonded with Copper/Niobium/Copper Interlayers  

E-print Network

Fracture and Fatigue Behavior at Ambient and Elevated Temperatures of Alumina Bonded with Copper/Niobium/Copper-phase bonded using copper/niobium/copper interlayers have been investigated at both room and elevated, residual copper at the interface deformed and remained adhered to both sides of the fracture surface

Ritchie, Robert

215

The Fission Yeast Copper-sensing Transcription Factor Cuf1 Regulates the Copper Transporter Gene Expression through an  

E-print Network

The Fission Yeast Copper-sensing Transcription Factor Cuf1 Regulates the Copper Transporter Gene of copper transport is essential for copper homeostasis and growth in yeast. Analysis of regulatory regions in the promoter of the ctr4 copper transporter gene in fission yeast Schizosaccharomyces pombe re- veals

Labbé, Simon

216

Nanocomposites of metallic copper and spinel ferrite films: Growth and self-assembly of copper particles  

Microsoft Academic Search

Nanocomposites of metallic copper and iron oxides films have been prepared by RF-sputtering of pure CuFeO2 delafossite target. The films are made of copper and spinel ferrite crystallites of less than 10 nm in diameter. The content of metallic copper and the ferrite composition depend on the sputtering conditions. For the shortest substrate-target distances, films are made of copper and

Emmanuelle Mugnier; Isabelle Pasquet; Antoine Barnabé; Lionel Presmanes; Corine Bonningue; Philippe Tailhades

2005-01-01

217

The Copper Chaperone Atox1 in Canine Copper Toxicosis in Bedlington Terriers  

Microsoft Academic Search

Copper toxicosis, resulting in liver disease, commonly occurs in Bedlington terriers. This recessively inherited disorder, similar in many respects to Wilson disease, is of particular interest because the canine Atp7b gene, homologous to ATP7B defective in Wilson disease, is not responsible for canine copper toxicosis as has been expected. Atox1, a copper chaperone delivering copper to Atp7b, therefore became a

Manoj. S. Nanji; Diane. W. Cox

1999-01-01

218

Copper(I) and copper(II) complexes of an ethylene cross-bridged cyclam  

E-print Network

Copper(I) and copper(II) complexes of an ethylene cross-bridged cyclam Timothy J. Hubin,a Nathaniel and crystal structures of (4,11-dibenzyl- 1,4,8,11-tetraazabicyclo[6.6.2]hexadecane- 4 N)copper(I) hexa)- copper(II) bis(hexa¯uorophosphate), [Cu(C2H3N)(C26H38- N4)](PF6)2, are described. The CuI ion

Hubin, Tim

219

Advantages and challenges of increased antimicrobial copper use and copper mining  

Microsoft Academic Search

Copper is a highly utilized metal for electrical, automotive, household objects, and more recently as an effective antimicrobial\\u000a surface. Copper-containing solutions applied to fruits and vegetables can prevent bacterial and fungal infections. Bacteria,\\u000a such as Salmonellae and Cronobacter sakazakii, often found in food contamination, are rapidly killed on contact with copper alloys. The antimicrobial effectiveness of\\u000a copper alloys in the

Jutta Elguindi; Xiuli Hao; Yanbing Lin; Hend A. Alwathnani; Gehong Wei; Christopher Rensing

220

The direct electrorefining of copper matte  

NASA Astrophysics Data System (ADS)

Direct electrorefining of copper matte would be a desirable alternative to copper converting and its associated troublesome sulfur dioxide emissions. After more than 100 years of study, however, no commercial process has been developed, even though an analogous process for the direct electrorefining of nickel matte anodes has been operating successfully for several decades. The unique difficulties associated with copper matte electrorefining are related to the properties of the matte's decomposition products.

McKay, Douglas J.

1993-03-01

221

Copper chloride cathode for a secondary battery  

NASA Technical Reports Server (NTRS)

Higher energy and power densities are achieved in a secondary battery based on molten sodium and a solid, ceramic separator such as a beta alumina and a molten catholyte such as sodium tetrachloroaluminate and a copper chloride cathode. The higher cell voltage of copper chloride provides higher energy densities and the higher power density results from increased conductivity resulting from formation of copper as discharge proceeds.

Bugga, Ratnakumar V. (inventor); Distefano, Salvador (inventor); Nagasubramanian, Ganesan (inventor); Bankston, Clyde P. (inventor)

1990-01-01

222

Copper sulfate toxicosis in commercial laying hens.  

PubMed

A flock of 51-week-old leghorn hens experienced a 16% drop in egg production in a single week. The layer ration contained 1477 ppm copper from the addition of copper sulfate. Severe oral ulcers were present in the pharynx. Oral ulcers, reduced feed intake, and a drop in egg production occurred when a ration containing 1437 ppm copper was evaluated experimentally. PMID:8713042

Gilbert, R W; Sander, J E; Brown, T P

1996-01-01

223

Material flows generated by pyromet copper smelting  

USGS Publications Warehouse

Copper production through smelting generates large volumes of material flows. As copper contained in ore becomes copper contained in concentrate to be fed into the smelting process, it leaves behind an altered landscape, sometimes mine waste, and always mill tailings. Copper concentrate, fluxing materials, fuels, oxygen, recyclables, scrap and water are inputs to the process. Dust (recycled), gases - containing carbon dioxide (CO2) (dissipated) and sulfur dioxide (SO2) (mostly collected, transformed and sold) and slag (discarded or sold) - are among the significant process outputs. This article reports estimates of the flows of these input/output materials for a particular set of smelters studied in some countries.

Goonan, T.G.

2005-01-01

224

Synthetic Fluorescent Probes for Monovalent Copper  

PubMed Central

Fluorescent probes are powerful and cost-effective tools for the detection of metal ions in biological systems. Compared to non-redox-active metal ions, the design of fluorescent probes for biological copper is challenging. Within the reducing cellular environment, copper is predominantly present in its monovalent oxidation state; therefore, the design of fluorescent probes for biological copper must take into account the rich redox and coordination chemistry of Cu(I). Recent progress in understanding the underlying solution chemistry and photophysical pathways led to the development of new probes that offer high fluorescence contrast and excellent selectivity towards monovalent copper. PMID:23769869

Fahrni, Christoph J.

2013-01-01

225

Radioactivity at the Copper Creek copper lode prospect, Eagle district, east-central Alaska  

USGS Publications Warehouse

Investigation of radioactivity anomalies at the Copper Creek copper lode prospect, Eagle district, east-central Alaska, during 1949 disclosed that the radioactivity is associated with copper mineralization in highly metamorphosed sedimentary rocks. These rocks are a roof pendant in the Mesozoic "Charley River" batholith. The radioactivity is probably all due to uranium associated with bornite and malachite.

Wedow, Helmuth; Tolbert, Gene Edward

1952-01-01

226

Neutron-activation analysis applied to copper ores and artifacts  

NASA Technical Reports Server (NTRS)

Neutron activation analysis is used for quantitative identification of trace metals in copper. Establishing a unique fingerprint of impurities in Michigan copper would enable identification of artifacts made from this copper.

Linder, N. F.

1970-01-01

227

SURVIVAL AND IMMUNE RESPONSE OF COHO SALMON EXPOSED TO COPPER  

EPA Science Inventory

Vaccination with Vibrio anguillarum by oral administration during copper exposure and intraperitoneal injection prior to copper exposure was employed to investigate the effects of copper upon survival and the immune response of juvenile coho salmon (Oncorhynchus kisutch). Followi...

228

Title. ATP7B copper-regulated traffic and association with the tight junctions: copper excretion into Short title. ATP7B and copper excretion by liver  

E-print Network

1 Title. ATP7B copper-regulated traffic and association with the tight junctions: copper excretion into the bile Short title. ATP7B and copper excretion by liver Authors. Sonia Hernandez*§ , Yo Tsuchiya manuscript Gastroenterology 2008;134(4):1215-23 #12;2 Abstract The copper transporter ATP7B plays a central

Boyer, Edmond

229

Chronic Copper Poisoning in Sheep.  

E-print Network

LIBRARY, - A & M COLLEGE, CAiQFUS. E-109-8M-L180 TEXAS AGRICULTURAL EXPERIMENT STATION A. B. CONNER, DIRECTOR COLLEGE STATION: BRAZOS COUNTY. TEXAS BULLETIN NO. 499 DECEMBER, 1934 DIVISION OF VETERINARY SCIENCE CHRONIC COPPER POISONING.... Beasley. $4. S., Asst. Agronomist S. D. Reynolds, Jr., Feed Inspector Publications : P. A. Moore, Feed Inspector A. I3 Jackson, Chief E. J. Wilson, B. S.. Feed Inspector H. G. Wickes. D. V. M.. Feed Inspector SUBSTATIO~L>'., No. 1. Beeville. Bee...

Boughton, I. B. (Ivan Bertrand); Hardy, W. T. (William Tyree)

1934-01-01

230

Copper-complexing ligands produced by an intact estuarine microbial community in response to copper stress.  

NASA Astrophysics Data System (ADS)

Copper is both an important nutrient and a pollutant in the marine environment. By studying the interactions between microorganisms and copper in the Elizabeth River (VA), home to a major Naval Base, we field tested the hypothesis that picoplankton and/or bacterioplankton produce strong, copper-complexing ligands in response to elevated copper concentrations. A simple light/ dark test was used to distinguish between heterotrophic and phototrophic ligand production. Samples were bottled and moored, submerged one meter, for a week. Direct counts using DAPI stain and epiflourescence were conducted to find concentrations of picoplankton and bacterioplankton. Using cathodic stripping voltammetry, we found the total copper concentrations, and then from a titration of the ligands by copper, the ligand concentrations and conditional stability constants were obtained. The Elizabeth River naturally had between 10-20 nM total dissolved copper concentrations. However when copper complexation was considered we found that the levels of bio-available Cu(II) ions were much lower. In fact in the natural samples the levels were not high enough to affect the relative reproductive rates of several microorganisms. Naturally there was a 50 nM "buffer zone" of ligand to total dissolved copper concentration. Furthermore, when stressed with excess copper, healthy picoplankton produced enough ligand to alleviate toxicity, and rebuild the buffer zone. However bacterioplankton only produced enough ligand so that they were no longer affected. Therefore, intact estuarine communities regulate copper bioavailability and toxicity with ligand production.

Bingham, J.; Dryden, C.; Gordon, A.

2002-12-01

231

Potentially novel copper resistance genes in copper-enriched activated sludge revealed by metagenomic analysis.  

PubMed

In this study, we utilized the Illumina high-throughput metagenomic approach to investigate diversity and abundance of both microbial community and copper resistance genes (CuRGs) in activated sludge (AS) which was enriched under copper selective stress up to 800 mg/L. The raw datasets (~3.5 Gb for each sample, i.e., the copper-enriched AS and the control AS) were merged and normalized for the BLAST analyses against the SILVA SSU rRNA gene database and self-constructed copper resistance protein database (CuRD). Also, the raw metagenomic sequences were assembled into contigs and analyzed based on Open Reading Frames (ORFs) to identify potentially novel copper resistance genes. Among the different resistance systems for copper detoxification under the high copper stress condition, the Cus system was the most enriched system. The results also indicated that genes encoding multi-copper oxidase played a more important role than those encoding efflux proteins. More significantly, several potentially novel copper resistance ORFs were identified by Pfam search and phylogenic analysis. This study demonstrated a new understanding of microbial-mediated copper resistance under high copper stress using high-throughput shotgun sequencing technique. PMID:25081552

Li, Li-Guan; Cai, Lin; Zhang, Xu-Xiang; Zhang, Tong

2014-12-01

232

Synthesis, crystal structure and electronic properties of the new iron selenide Ba{sub 9}Fe{sub 4}Se{sub 16}  

SciTech Connect

The new ternary selenide Ba{sub 9}Fe{sub 4}Se{sub 16} has been synthesized from the reaction of appropriate amounts of elements at high temperature in a silica sealed tube. The compound crystallizes in the tetragonal space group I4{sub 1}/a with a=10.0068(3) Å and c=35.6415(9) Å, Z=4. It is an isostructural compound to the sulfide ?-Ba{sub 9}Fe{sub 4}S{sub 15}, which is a high temperature polymorph of ?-Ba{sub 9}Fe{sub 4}Se{sub 15} that belongs to the indefinitely adaptive phases series Ba{sub 3}Fe{sub 1+x}S{sub 5}, 0?x?1. X-ray powder diffraction and TEM analyses of the synthesized compound were used to determine the phase composition and the structure. The crystal structure can be viewed as overlapping sections along the c axis. Those sections are formed by the coordination polyhedra around barium atoms which can be described as trigonal prisms and bidisphenoids. Within the sections formed by barium polyhedra, isolated pairs of edge sharing FeSe{sub 4} tetrahedra are found. Magnetic measurements performed on Ba{sub 9}Fe{sub 4}Se{sub 16} indicate an antiferromagnetic behavior with Néel temperature of ?13 K. Possible influence of air exposure on the magnetic properties is also discussed here. The electric measurements show an insulating behavior below 160 K and the dielectric permittivity and loss tangent at the lowest frequency measured reveal a change of slope very close to T{sub N}. However no magneto dielectric effect was evidenced for magnetic fields of up to 3 T. Activation energy, E{sub A}=0.18 eV, was extracted from the AC conductivity plot in the temperature range of 160–300 K. -- Graphical abstract: Experimental electron diffraction (ED) patterns of Ba{sub 9}Fe{sub 4}Se{sub 16} recorded along a-[010]. Highlights: • A new iron selenide material. • A structure resolution by combination of XRD and TEM. • Magnetic properties of the new compound Ba{sub 9}Fe{sub 4}Se{sub 16} are discussed.

Berthebaud, David, E-mail: david.berthebaud@ensicaen.fr; Preethi Meher, K.R.S.; Pelloquin, Denis; Maignan, Antoine

2014-03-15

233

Regulation of gemma formation in the copper moss Scopelophila cataractae by environmental copper concentrations.  

PubMed

Considerable attention has recently been focused on the use of hyperaccumulator plants for the phytoremediation of soils contaminated with heavy metals. The moss, Scopelophila cataractae (Mitt.) Broth., is a typical hyperaccumulator that is usually observed only in copper-rich environments and which accumulates high concentrations of copper in its tissues. However, many of the physiological processes and mechanisms for metal hyperaccumulation in S. cataractae remain unknown. To address this issue, we examined the mechanisms regulating gemma formation, which is considered the main strategy by which S. cataractae relocates to new copper-rich areas. From this study we found that treatment of S. cataractae with high concentrations of copper suppressed gemma formation but promoted protonemal growth. The suppressive effect was not observed by treatment with heavy metals other than copper. These results suggest the importance of copper-sensitive asexual reproduction in the unique life strategy of the copper moss, S. cataractae. PMID:21082328

Nomura, Toshihisa; Hasezawa, Seiichiro

2011-09-01

234

Application of INKORAM-75 copper corrosion inhibitor  

NASA Astrophysics Data System (ADS)

Treatment of cooling water with INKORAM-75 copper corrosion inhibitor is applied for reducing corrosion processes in the copper-containing alloy of which turbine condensers are made. The results obtained from industrial trial of the INKORAM-75 inhibitor in the service cooling water system of the Novovoronezh NPP Units 3 and 4 are presented.

Galanin, A. V.; Fedorov, A. I.; Kucherenko, O. V.; Gromov, A. F.

2014-02-01

235

Lead and Copper Control 101-slides  

EPA Science Inventory

This presentation is an overview of the most important water treatment strategies for the control of lead and copper release from drinking water corrosion. In addition to the sections specifically on lead and copper treatment, sections are included that cover sampling to find le...

236

CONTROL OF COPPER SMELTER FUGITIVE EMISSIONS  

EPA Science Inventory

This report deals with fugitive emissions from copper smelting and with related emission control measures. The study involved evaluation of the controls now used in the copper smelting industry and development of suggestions for alternative control devices and practices. A brief ...

237

Common Sense Copper and RF Guns  

SciTech Connect

The purpose of this document is to gather together both fundamental information on copper and on the cleaning and operation of copper in RF gun structures. While incomplete, this is a living document and will be added to and updated as necessary.

Mulhollan, G.

2005-01-18

238

Electrolytic Corrosion of Iron and Copper  

Microsoft Academic Search

IT is generally accepted that if cast iron and copper are coupled together in a brine solution, the iron, being the less noble member, is likely to suffer corrosion. The copper, on the other hand, will be made `more negative' by contact with the iron and will be prevented in greater or less degree from corroding. The classical work on

W. F. Higgins

1954-01-01

239

Copper metallization of stainless steels. Final report  

SciTech Connect

Stainless steel plates were vacuum metallized with pure copper films 0.004 inch thick. Prior to metallization the surfaces were cleaned with EPA-approved detergents. A thin layer of chromium was sputtered for improved adhesion followed by sputtering of the copper. Results showed excellent adhesion of the sputtered films to the substrates.

Rosenblum, B.Z.

1994-09-01

240

COPPER PITTING AND PINHOLE LEAK RESEARCH STUDY  

EPA Science Inventory

Localized copper corrosion or pitting is a significant problem at many water utilities across the United States. Copper pinhole leak problems resulting from extensive pitting are widely under reported. Given the sensitive nature of the problem, extent of damage possible, costs o...

241

Chronic poisoning by copper in tap water: II. Copper intoxications with predominantly systemic symptoms.  

PubMed

Copper can induce acute and chronic intoxications in humans. Copper in tap water has caused a series of severe systemic diseases in Germany in recent years (chronic copper poisoning, CCuP). From the clinical point of view it has been difficult to establish the diagnosis on the basis of clinical and laboratory methods. In a retrospective study, we therefore looked for essential clinical signs as well as laboratory findings which might be typical and essential for the diagnosis of CCuP. - We observed that in patients with severe systemic CCuP not only the liver but also several other organs have been the target of copper. As a proof copper overload has been measured. The latter results are presented here. - During or shortly after exposure "free" serum copper (= non-ceruloplasmin-bound copper) was significantly elevated in all patients (range 5.1 to 47.1 micromol/l, or 25.7 to 56.2 % of total serum copper). The normal upper limits in infants according to Salmenperä (8) are: 0.3 micromol/l, or 1.6 % of total serum copper. - Total serum copper was elevated in 14/16 patients: 13.7 to 30.1 micromol/l in sick infants (normal upper level: 12.6 micromol/l), and 17.0 to 27.2 in sick children (normal upper level for children and adults: 21.4 micromol/l). - Urine copper excretion was found elevated in 9/10 patients, with a range of 11 to 456 microg/dl (normal upper level in adults: 15 microg/dl). - Our results show that patients with systemic CCuP are in a "hypercupric" state. The data thus firstly prove that indeed the putative agent copper is found in excess in the patients and secondly show that the estimation of "free" copper in serum and the measurement of copper in urine are reliable diagnostic methods. Elevation of total serum copper (even though not specific) can give a first hint to the diagnosis. - The hypercupric state of systemic CCuP can be differentiated from that of Wilson's disease by (1) normal levels of ceruloplasmin and (2) the observation that values for free copper in serum or urinary copper normalize in an environment without copper in tap water, for instance in a hospital. PMID:10383876

Eife, R; Weiss, M; Müller-Höcker, M; Lang, T; Barros, V; Sigmund, B; Thanner, F; Welling, P; Lange, H; Wolf, W; Rodeck, B; Kittel, J; Schramel, P; Reiter, K

1999-06-28

242

Thermo-optical characterization of cadmium selenide/zinc sulfide (CdSe/ZnS) quantum dots embedded in biocompatible materials.  

PubMed

Cadmium selenide/zinc sulfide (CdSe/ZnS) core-shell quantum dots (QDs) embedded in biocompatible materials were thermally and optically characterized with a thermal lens (TL) technique. Transient TL measurements were performed with a mode-mismatched, dual-beam (excitation and probe) configuration. A thermo-optical study of the CdSe/ZnS QDs was performed for different core diameters (3.5, 4.0, 5.2, and 6.6 nm) in aqueous solution and synthetic saliva, and three different core diameters (2.4, 2.9, and 4.1 nm) embedded in restorative dental resin (0.025% by mass). The thermal diffusivity results are characteristic of the biocompatible matrices. The radiative quantum efficiencies for aqueous solution and biofluid materials are dependent on the core size of the CdSe/ZnS core-shell QDs. The results obtained from the fluorescence spectral measurements for the biocompatible materials support the TL results. PMID:24067629

Pilla, Viviane; Alves, Leandro P; Iwazaki, Adalberto N; Andrade, Acácio A; Antunes, Andrea; Munin, Egberto

2013-09-01

243

Na3.88Mo15Se19: a novel ternary reduced molybdenum selenide containing Mo6 and Mo9 clusters  

PubMed Central

The structure of tetrasodium penta­deca­molybdenum nona­deca­selenide, Na3.88Mo15Se19, is isotypic with the In3+xMo15Se19 compounds [Grüttner et al. (1979 ?). Acta Cryst. B35, 285–292]. It is characterized by two cluster units, Mo6Sei 8Sea 6 and Mo9Sei 11Sea 6 (where i represents inner and a apical atoms), that are present in a 1:1 ratio. The cluster units are centered at Wyckoff positions 2b and 2c and have point-group symmetry -3 and -6, respectively. The clusters are inter­connected through additional Mo—Se bonds. In the title compound, the Na+ cations replace the trivalent as well as the monovalent indium atoms present in In3.9Mo15Se19. One Mo, one Se and one Na atom are situated on mirror planes, and two other Se atoms and one Na atom [occupancy 0.628?(14)] are situated on threefold rotation axes. The crystal studied was twinned by merohedry with refined components of 0.4216?(12) and 0.5784?(12). PMID:24098158

Salloum, Diala; Gougeon, Patrick; Gall, Philippe

2013-01-01

244

Synthesis, characterization and electrochemical characterization of lead selenide sub-micron particles capped with a benzoate ligand and prepared at different temperatures  

NASA Astrophysics Data System (ADS)

Semiconductor materials offer several potential benefits as active elements in the development of harvesting-energy conversion technologies. In particular, lead selenide (PbSe) semiconductors have been used and proposed to design solar energy harvesting devices, IR sensors, FET devices, etc. Lead salts have drawn particular attention from the applied and fundamental research communities due to their exceptionally strong quantum confinement effects. Several syntheses of PbSe have been proposed using long chain surfactants to allow the formation of particles and nanoparticles. Here we present a synthesis using benzoic acid as the capping ligand in ambient atmosphere. Although the particles are not in nanometric size, we compare the crystal structure (using x-ray powder diffraction data), the near infrared and mid-infrared absorption properties of PbSe using oleic acid as the capping ligand with PbSe using benzoic acid as the capping ligand. The new synthetized particles were shown to have similar crystal structure and absorb light in the near infrared region at 1410 nm. We also performed cyclic voltammetry of these particles drop-casted in the surface of a glassy carbon electrode. The particles showed electrochemical behavior with an oxidation peak near (?402 ± 5 mV) versus Ag/AgCl reference electrode. The particles seem to form a polymeric film at the surface of a glassy carbon electrode.

Rodríguez-Rodríguez, Weyshla A.; Colón, Jadiel; Guzmán, Roger; Rivera, Harry; Santiago-Berríos, Mitk’El B.

2014-09-01

245

Evolution of the phases and chemical composition during the formation of CIS thin films prepared by interdiffusion process in selenides layers  

NASA Astrophysics Data System (ADS)

CuInSe 2 (CIS) thin films were prepared using a novel procedure involving the interdiffusion of the species present in the bilayer system {InxSey}/{CuzSey} assisted by a post deposition annealing in a high-pressure atmosphere of elemental selenium. The influence of the annealing temperature on the phase and chemical composition of both the single precursor layers and the bilayer system was established through X-ray diffraction (XRD) using a specially developed computer programme and energy dispersive spectroscopy (EDS) measurements. The chemical composition homogeneity in the bulk of the resulting samples was also studied by (Auger electron spectroscopy) AES depth profile measurements. The possible chemical reactions which give rise to the formation of a range of binary and ternary compounds are given on the basis of EDS measurements and the identification, with a high degree of reliability, of the phases present in both the bilayer system and the selenide precursor layers. A special methodology was developed for the determination of the crystallographic phases which combined commercial software criteria (in this case APD (automated powder diffraction)) together with a new criterion, which takes into account the reflections in all parallel planes (when they exist) of each of the phases present in the sample studied.

Teherán, P.; Cediel, G.; Caicedo, L. M.; Cota, L.; Leal, H.; Rodríguez, J. A.; Gordillo, G.

1998-01-01

246

Electronic characterization of defects in narrow gap semiconductors: Comparison of electronic energy levels and formation energies in mercury cadmium telluride, mercury zinc telluride, and mercury zinc selenide  

NASA Technical Reports Server (NTRS)

The project has evolved to that of using Green's functions to predict properties of deep defects in narrow gap materials. Deep defects are now defined as originating from short range potentials and are often located near the middle of the energy gap. They are important because they affect the lifetime of charge carriers and hence the switching time of transistors. We are now moving into the arena of predicting formation energies of deep defects. This will also allow us to make predictions about the relative concentrations of the defects that could be expected at a given temperature. The narrow gap materials mercury cadmium telluride (MCT), mercury zinc telluride (MZT), and mercury zinc selenide (MZS) are of interest to NASA because they have commercial value for infrared detecting materials, and because there is a good possibility that they can be grown better in a microgravity environment. The uniform growth of these crystals on earth is difficult because of convection (caused by solute depletion just ahead of the growing interface, and also due to thermal gradients). In general it is very difficult to grow crystals with both radial and axial homogeneity.

Patterson, James D.; Li, Wei-Gang

1995-01-01

247

ESCA studies of copper oxides and copper molybdates  

Microsoft Academic Search

Valence band, Cu 2p3\\/2, O 1s, Mo 3d, and Cu L3M45M45 photoelectron and X-ray-induced Auger spectra were recorded for metallic copper, Cu2O, CuO, Cu2Mo3O10, Cu6Mo4O15, CuMoO4, Cu3Mo2O9, and Cu3.85Mo3O12. Cu 2p3\\/2 binding energy is 0.9 eV lower for Cu+-containing molybdates than for Cu2O and 0.7 eV higher for Cu2+-containing molybdates with respect to that of CuO. Calculation of net chemical

J. Haber; T. Machej; L. Ungier; J. Ziólkowski

1978-01-01

248

Copper accumulation in channel catfish (Ictalurus punctatus) exposed to water borne copper sulfate  

SciTech Connect

Liver and axial muscle of channel catfish (Ictalurus punctatus) was analyzed for residual copper after exposure to water borne copper sulfate. Copper sulfate was continuously introduced into well water in three fiber glass tanks to achieve 1.7 mg/L, 2.7 mg/L and 3.6 mg/L copper sulfate concentrations in exposure waters. Milli-Q quality water was metered into a fourth tank at the same rate for unexposed fish. Actual levels of copper in exposure waters were determined by daily sampling and analysis by graphite furnace atomic absorption spectrophotometry (GFAA). Tissue samples were taken from six fish from each of the exposed and unexposed tanks at two-week intervals, Samples were collected until tissue analysis indicated an equilibrium had been established between the uptake and elimination in both the muscle and liver tissue. Elimination was followed until a clear rate of deputation could be established. Samples were digested in nitric acid in a micro wave digestor and analyzed by GFAA. Results of tissue analysis will be presented to demonstrate bioaccumulation and the effect of copper concentration, length of copper exposure, and gender on copper uptake, establishment of tissue:environmental copper equilibrium, and rate of copper elimination following exposure.

Hobbs, M. [Oak Ridge Inst. for Science and Education, TN (United States); Griffin, B. [National Biological Service, Stuttgart, AR (United States); Schlenk, D. [Univ. of Mississippi, Oxford, MS (United States); Kadlubar, F.; Brand, C.D. [National Center for Toxicological Research, Jefferson, AR (United States)

1995-12-31

249

THE IMPACT OF ORTHOPHOSPHATE ON COPPER CORROSION AND CHLORINE DEMAND  

EPA Science Inventory

In 1991, EPA promulgated the Lead and Copper Rule, which established a copper action level of 1.3 mg/L in a 1-liter, first-draw sample collected from the consumer?s tap. Excessive corrosion of copper can lead to elevated copper levels at the consumer's tap, and in some cases, can...

250

Bioinorganic Chemical Modeling of Dioxygen-Activating Copper Proteins.  

ERIC Educational Resources Information Center

Discusses studies done in modeling the copper centers in the proteins hemocyanin (a dioxygen carrier), tyrosinase, and dopamine beta-hydroxylase. Copper proteins, model approach in copper bioinorganic chemistry, characterization of reversible oxygen carriers and dioxygen-metal complexes, a copper mono-oxygenase model reaction, and other topics are…

Karlin, Kenneth D.; Gultneh, Yilma

1985-01-01

251

Antibacterial Effects of Solid Copper on Waterborne Bacteria  

Microsoft Academic Search

Objectives\\/Goals I came across an article about people in India who are throwing copper and silver coins into their rivers. They believe copper and silver coins will be able to disinfect their polluted water systems. I designed an experiment to test the antibacterial effects of copper in water. After researching, I hypothesized that solid copper might have a moderate effect

Anna N. Shuster

252

Thermal enrichment and speciation of copper in rice husk ashes.  

PubMed

Copper(II) was considerably enriched in the residual ash via thermal treatment of copper-sorbed rice husk at 700-1100°C for 2h, and the copper speciation was quantitatively determined with X-ray absorption spectroscopy. After the thermal process, the resulting ash only represents by weight 18.7-26.4% of the pre-heated samples. Copper content in the ashes is >7% which is far above the required minimum copper content in copper ores for the copper smelting sector, 0.5%. Crystalline SiO(2) is observed only in the ash generated at 1100°C, with more copper in this ash being available for leaching in acidic solution. It is suggested that this is due to the considerable dissimilarity in crystalline structure between copper compounds and crystalline SiO(2). No chemical reaction between copper and SiO(2) is observed in any ash. In fact, we suggest that the SiO(2) crystalline phase repels copper during the thermal process; this would make it easy to extract copper from the ashes. For copper speciation in the ashes, CuO merely represents 0-12% of the total copper, while Cu(2)O and Cu(0) represent 34-42% and 46-63%, respectively. The lower copper oxidation state would be beneficial for the copper smelting process due to less usage of coke. PMID:20869164

Wei, Yu-Ling; Hu, Ming-Jan; Peng, Yen-Hsun

2010-12-15

253

Biotransference and biomagnification of selenium copper, cadmium, zinc, arsenic and  

E-print Network

Biotransference and biomagnification of selenium copper, cadmium, zinc, arsenic and lead the biotransference of selenium copper, cadmium, zinc, arsenic and lead was measured in a contaminated seagrass. There was no evidence of copper, cadmium, zinc or lead biomagnification within the food web examined. Copper, cadmium

Canberra, University of

254

Glutaredoxin1 protects neuronal cells from copper-induced toxicity.  

PubMed

Glutaredoxin1 (GRX1) is a glutathione (GSH)-dependent thiol oxidoreductase. The GRX1/GSH system is important for the protection of proteins from oxidative damage and in the regulation of protein function. Previously we demonstrated that GRX1/GSH regulates the activity of the essential copper-transporting P1B-Type ATPases (ATP7A, ATP7B) in a copper-responsive manner. It has also been established that GRX1 binds copper with high affinity and regulates the redox chemistry of the metallochaperone ATOX1, which delivers copper to the copper-ATPases. In this study, to further define the role of GRX1 in copper homeostasis, we examined the effects of manipulating GRX1 expression on copper homeostasis and cell survival in mouse embryonic fibroblasts and in human neuroblastoma cells (SH-SY5Y). GRX1 knockout led to cellular copper retention (especially when cultured with elevated copper) and reduced copper tolerance, while in GRX1-overexpressing cells challenged with elevated copper, there was a reduction in both intracellular copper levels and copper-induced reactive oxygen species, coupled with enhanced cell proliferation. These effects are consistent with a role for GRX1 in regulating ATP7A-mediated copper export, and further support a new function for GRX1 in neuronal copper homeostasis and in protection from copper-mediated oxidative injury. PMID:24816595

Cater, Michael A; Materia, Stephanie; Xiao, Zhiguang; Wolyniec, Kamil; Ackland, Susan M; Yap, Yann W; Cheung, Nam Sang; La Fontaine, Sharon

2014-08-01

255

COPPER--2003 21.1 By Daniel L. Edelstein  

E-print Network

COPPER--2003 21.1 COPPER By Daniel L. Edelstein Domestic survey data and tables were prepared copper products; one of the refineries operated for only a portion of the year. Scrap was also consumed declined by about 50,000 t to 2.25 Mt owing to the dismantling of Cerro Copper Products secondary refinery

256

COPPER--2000 23.1 By Daniel L. Edelstein  

E-print Network

COPPER--2000 23.1 COPPER By Daniel L. Edelstein Domestic survey data and tables were prepared. In 2000, mine production of recoverable copper in the United States continued its downward slide to mine closures and cutbacks carried forward from midyear 1999, high energy costs coupled with low copper

257

COPPER--1998 22.1 By Daniel L. Edelstein  

E-print Network

COPPER--1998 22.1 COPPER By Daniel L. Edelstein Domestic survey data and tables were prepared of recoverable copper in the United States reversed its decade-long upward trend, declining by about 80,000 metric tons to the lowest level since 1995. Mine cutbacks and closures were attributed to low copper

258

Metallochaperones Regulate Intracellular Copper Levels  

PubMed Central

Copper (Cu) is an important enzyme co-factor that is also extremely toxic at high intracellular concentrations, making active efflux mechanisms essential for preventing Cu accumulation. Here, we have investigated the mechanistic role of metallochaperones in regulating Cu efflux. We have constructed a computational model of Cu trafficking and efflux based on systems analysis of the Cu stress response of Halobacterium salinarum. We have validated several model predictions via assays of transcriptional dynamics and intracellular Cu levels, discovering a completely novel function for metallochaperones. We demonstrate that in addition to trafficking Cu ions, metallochaperones also function as buffers to modulate the transcriptional responsiveness and efficacy of Cu efflux. This buffering function of metallochaperones ultimately sets the upper limit for intracellular Cu levels and provides a mechanistic explanation for previously observed Cu metallochaperone mutation phenotypes. PMID:23349626

Pang, W. Lee; Kaur, Amardeep; Ratushny, Alexander V.; Cvetkovic, Aleksandar; Kumar, Sunil; Pan, Min; Arkin, Adam P.; Aitchison, John D.; Adams, Michael W. W.; Baliga, Nitin S.

2013-01-01

259

Penta­zirconium copper tribismuth  

PubMed Central

Penta­zirconium copper tribismuth, Zr5CuBi3, crystallizes in the hexa­gonal Hf5CuSn3 structure type. The asymmetric unit contains two Zr sites (site symmetries 3.2 and m2m), one Cu site (site symmetry 3.m) and one Bi site (site symmetry m2m). The environment of the Bi atoms is a tetra­gonal anti­prism with one added atom and a coordination number (CN) of 9. The polyhedron around the Zr1 atom is a defective cubo­octa­hedron with CN = 11. The bicapped hexa­gonal anti­prism (CN = 14) is typical for Zr2 atoms. The Cu atom is enclosed in a eight-vertex polyhedron (octa­hedron with two centered faces). The metallic type of bonding was indicated by an analysis of the inter­atomic distances and electronic structure calculation data. PMID:24109256

Balinska, Agnieszka; Tarasiuk, Ivan; Pavlyuk, Volodymyr

2013-01-01

260

Penta-zirconium copper tribismuth.  

PubMed

Penta-zirconium copper tribismuth, Zr5CuBi3, crystallizes in the hexa-gonal Hf5CuSn3 structure type. The asymmetric unit contains two Zr sites (site symmetries 3.2 and m2m), one Cu site (site symmetry 3.m) and one Bi site (site symmetry m2m). The environment of the Bi atoms is a tetra-gonal anti-prism with one added atom and a coordination number (CN) of 9. The polyhedron around the Zr1 atom is a defective cubo-octa-hedron with CN = 11. The bicapped hexa-gonal anti-prism (CN = 14) is typical for Zr2 atoms. The Cu atom is enclosed in a eight-vertex polyhedron (octa-hedron with two centered faces). The metallic type of bonding was indicated by an analysis of the inter-atomic distances and electronic structure calculation data. PMID:24109256

Balinska, Agnieszka; Tarasiuk, Ivan; Pavlyuk, Volodymyr

2013-01-01

261

Copper toxicosis in sheep: a case report.  

PubMed

Two ewes died after being fed rabbit ration and mineral salts designated for cows. This food is known to contain copper levels above that indicated for sheep. Blood counts revealed anemia, and serological tests showed high blood urea nitrogen, glutamic pyruvic transaminase and glutamic oxalacetic transaminase values. At necropsy, the animals had hepatopathy and nephropathy. Hepatic copper levels were 414 ppm. Histological examination revealed chronic active hepatitis with bile casts and tubular nephrosis. The liver, spleen and kidneys had hemosiderosis. This was attributed to the massive hemolysis caused by the copper. The liver failure and hemolytic anemia caused death in these sheep. PMID:9554065

Maiorka, P C; Massoco, C O; de Almeida, S D; Gorniak, S L; Dagli, M L

1998-04-01

262

Copper-Exchanged Zeolite L Traps Oxygen  

NASA Technical Reports Server (NTRS)

Brief series of simple chemical treatments found to enhance ability of zeolite to remove oxygen from mixture of gases. Thermally stable up to 700 degrees C and has high specific surface area which provides high capacity for adsorption of gases. To increase ability to adsorb oxygen selectively, copper added by ion exchange, and copper-exchanged zeolite reduced with hydrogen. As result, copper dispersed atomically on inner surfaces of zeolite, making it highly reactive to oxygen, even at room temperature. Reactivity to oxygen even greater at higher temperatures.

Sharma, Pramod K.; Seshan, Panchalam K.

1991-01-01

263

In situ deposits of copper and copper oxide containing condensation polyimide films  

NASA Technical Reports Server (NTRS)

Novel copper-polyimide composites have been synthesized via simultaneous thermal decomposition of solid solutions of bis (trifluoroacetylacetonato) copper (II) and thermal cyclodehydration of polyimide acid. In contrast to conventional filled polymer composites which are prepared by dispersion of particles or fibers in a polymer matrix this study has yielded in general uniform Cu or CuO dispersions of very small particle size that reside near the film surface that was exposed to the atmosphere during curing. The nature of the copper deposit, the thickness of the copper deposit, and the polyimide overlayer which bonds the copper to the polymer substrate depend on the curing atmosphere used. A variety of analytical surface methods along with thermogravimetric analysis and variable temperature (surface and volume) electrical resistivity measurements have been used to characterize these thin, flexible copper doped polyimide films.

Porta, G. M.; Taylor, L. T.

1987-01-01

264

Copper localization, elemental content, and thallus colour in the copper hyperaccumulator lichen Lecanora sierrae from California  

USGS Publications Warehouse

An unusual dark blue-green lichen, Lecanora sierrae, was discovered over 30 years ago by Czehura near copper mines in the Lights Creek District, Plumas County, Northern California. Using atomic absorption spectroscopy, Czehura found that dark green lichen samples from Warren Canyon contained 4% Cu in ash and suggested that its colour was due to copper accumulation in the cortex. The present study addressed the hypothesis that the green colour in similar material we sampled from Warren Canyon in 2008, is caused by copper localization in the thallus. Optical microscopy and electron microprobe analysis of specimens of L. sierrae confirmed that copper localization took place in the cortex. Elemental analyses of L. sierrae and three other species from the same localities showed high enrichments of copper and selenium, suggesting that copper selenates or selenites might occur in these lichens and be responsible for the unusual colour. Copyright ?? 2011 British Lichen Society.

Purvis, O.W.; Bennett, J.P.; Spratt, J.

2011-01-01

265

Copper localization, elemental content, and thallus colour in the copper hyperaccumulator lichen Lecanora sierra from California  

USGS Publications Warehouse

An unusual dark blue-green lichen, Lecanora sierrae, was discovered over 30 years ago by Czehura near copper mines in the Lights Creek District, Plumas County, Northern California. Using atomic absorption spectroscopy, Czehura found that dark green lichen samples from Warren Canyon contained 4% Cu in ash and suggested that its colour was due to copper accumulation in the cortex. The present study addressed the hypothesis that the green colour in similar material we sampled from Warren Canyon in 2008, is caused by copper localization in the thallus. Optical microscopy and electron microprobe analysis of specimens of L. sierrae confirmed that copper localization took place in the cortex. Elemental analyses of L. sierrae and three other species from the same localities showed high enrichments of copper and selenium, suggesting that copper selenates or selenites might occur in these lichens and be responsible for the unusual colour.

Purvis, O.W.; Bennett, J.P.; Spratt, J.

2011-01-01

266

Effect of dietary copper and zinc levels on tissue copper, zinc, and iron in male rats  

Microsoft Academic Search

The interaction between dietary copper and zinc as determined by tissue concentrations of trace elements was investigated\\u000a in male Sprague-Dawley rats. Animals were fed diets in a factorial design with two levels of copper (0.5, 5 ?g\\/g) and five\\u000a levels of zinc (1, 4.5, 10, 100, 1000 ?g\\/g) for 42 d. In rats fed the low copper diet, as dietary

Carl L. Keen; Nancy H. Reinstein; Jo Goudey-Lefevre; Michael Lefevre; Bo Lönnerdal; Barbara O. Schneeman; Lucille S. Hurley

1985-01-01

267

Analysis of copper flows in China from 1975 to 2010.  

PubMed

By applying substance flow analysis (SFA), the paper attempts to illustrate how copper utilization pattern has changed in the anthroposphere of China from 1975 to 2010. An analytical framework is firstly established and the detailed copper cycles of the specific years 1975, 1985, 1995, 2005 and 2010 are then characterized. Major conclusions include the following: (1) Chinese copper industry has made significant progress driven by large domestic copper demand since 1970s, especially after 1990s. Also the structure of copper industry has shifted from a basic industry to a processing industry. The share of secondary copper production in total refined copper has risen from 20% in 1975 to 38% in 2010; (2) the Chinese society has experienced a rapid copper accumulation since 1990s. The annual input flow to use stage jumped from only 334 Gg (that is 0.36 kg per capita copper consumption) in 1975 to 7,916 Gg (5.90 kg per capita) in 2010; (3) a large amount of copper has to be imported to meet the huge demand, mainly involving in copper concentrate, refined copper and copper scrap. And the NIR (Net Import Ratio) of the three was 53.0%, 38.7% and 63.0% in 2010, respectively; (4) domestically produced copper scrap increased from 74.5 Gg in 1975 to 711.2 Gg in 2010. Comparing it with import scrap and domestic new scrap we found that at current stage the in-use stock is still too small to generate high quantities of copper scrap for domestic secondary copper production. (5) Major copper losses occurred through copper Mining, Refining and WM&R, with the Mining exhibited the lowest copper utilization efficiency (CUE) among the three processes, and may have the great potential for increasing copper utilization rate in China. PMID:24530587

Zhang, Ling; Yang, Jiameng; Cai, Zhijian; Yuan, Zengwei

2014-04-15

268

Copper Transporting P-Type ATPases and Human Disease  

Microsoft Academic Search

Copper transporting P-type ATPases, designated ATP7A and ATP7B, play an essential role in mammalian copper balance. Impaired intestinal transport of copper, resulting from mutations in the ATP7A gene, lead to Menkes disease in humans. Defects in a similar gene, the copper transporting ATPase ATP7B, result in Wilson disease. This ATP7B transporter has two functions: transport of copper into the plasma

Diane W. Cox; Steven D. P. Moore

2002-01-01

269

Effort on calibration of infrared spark ablation of copper with synthetic copper standards  

NASA Astrophysics Data System (ADS)

Two types of copper samples, compact certified copper reference materials and calibration samples prepared from liquid doped, pressed copper powders, were studied in terms of accuracy of obtained calibration functions originating from infrared spark ablation. Additionally, corresponding particle size distributions of the aerosols from infrared spark ablation were recorded. It is shown that the differences in quantification results, originating from the two sets of calibration functions, could not mainly be ascribed to different particle size distributions of the two copper sample types. Possible other causes, as different ablation rates, parts of melting and differences of the chemical constitutions of the two sample types were explored.

Wienold, Julia; Traub, Heike; Bresch, Harald; Seeger, Stefan; Recknagel, Sebastian; Kipphardt, Heinrich

2011-06-01

270

Electroless deposition of copper and fabrication of copper micropatterns on CVD diamond film surfaces  

NASA Astrophysics Data System (ADS)

Electroless deposition of copper on as-grown and amino-modification diamond substrates was investigated. The compact and uniform copper films were successfully electrolessly deposited on as-grown and amino-modification diamond substrates after activation by Pd/Sn colloid nanoparticles. The adhesion interaction between copper films and diamond substrates was roughly estimated by the ultrasonic treatment. The results showed the higher adhesion interaction between copper films and amino-modification diamond substrates than that between the copper films and as-grown diamond substrates due to the greater attractive force between the Pd/Sn colloid nanoparticles and amino-modified diamond surface. The favorable copper micropatterns were successfully constructed on diamond film surfaces by means of the catalyst lift-off method and the copper lift-off method. Furthermore, the electrochemical behavior of copper-modified boron-doped diamond (BDD) was studied for glucose oxidation in 0.2 M sodium hydroxide solution by using cyclic voltammetry, and the result indicated that copper-modified BDD exhibited high catalytic activity to electrochemical oxidation of glucose in alkaline media.

Zhao, Jianwen; Tian, Ruhai; Zhi, Jinfang

2008-03-01

271

Identification of copper ions in aqueous and vitreous of eyes containing copper and iron foreign bodies.  

PubMed Central

The reliability of aqueous analysis by the atomic absorption spectrophotometer for copper ion content in samples from eyes containing intravitreal pure copper particles was investigated. It was demonstrated that values of copper ions rose well above the normal in the aqueous as well as in the vitreous of such eyes. The standard deviations of the mean values were generally high. It was also found that a similar copper ion content increase occurred in eyes containing iron particles. The possible clinical implications of these findings are discussed. PMID:1191617

Yassur, Y; Zauberman, H; Zidon, M

1975-01-01

272

Functional understanding of the versatile protein copper metabolism MURR1 domain 1 (COMMD1) in copper homeostasis.  

PubMed

Copper is an important cofactor in numerous biological processes in all living organisms. However, excessive copper can be extremely toxic, so it is vital that the copper level within a cell is tightly regulated. The damaging effect of copper is seen in several hereditary forms of copper toxicity in humans and animals. At present, Wilson's disease is the best-described and best-studied copper-storage disorder in humans; it is caused by mutations in the ATP7B gene. In dogs, a mutation in the COMMD1 gene has been found to be associated with copper toxicosis. Using a liver-specific Commd1 knockout mouse, the biological role of Commd1 in copper homeostasis has been confirmed. Yet, the exact mechanism by which COMMD1 regulates copper homeostasis is still unknown. Here, we give an overview of the current knowledge and perspectives on the molecular function of COMMD1 in copper homeostasis. PMID:24697840

Fedoseienko, Alina; Bartuzi, Paulina; van de Sluis, Bart

2014-05-01

273

Development of window layer for high efficiency high bandgap cadmium selenide solar cell for 4-terminal tandem solar cell applications  

NASA Astrophysics Data System (ADS)

Tandem solar cells fabricated from thin films provide promise of improved efficiency while keeping the processing costs low. CdSe as top cell are investigated in this work. CIGS has been a standardized process with lab efficiencies reaching 18% [53]. This dissertation focuses on the development of conductive window layer for the development of a high performance, high bandgap solar cell. ZnSe, Cu2-xSe, and ZnSexTe1-x are investigated as viable window layers of the top cell. ZnSe in undoped form forms a good junction with CdSe films, but the Voc from these devices could never exceed the 360mV mark, while the current densities approached 17.5mA/cm2 [61].To improve Voc's, the high contact energy at the ZnSe/Cu interface has to be overcome by replacing Cu with a metal having higher work function or doping the window layer to form a tunneling contact with Copper. Deposition of ZnSe from binary sources in presence of nitrogen plasma resulted in films with proper stoichiometry. However, doping could not be accomplished. ZnTe is easily dopable, and was the next alternative. ZnTe doping in presence of Nitrogen plasma resulted in Zn rich films. Hence doping of the ternary compound ZnSexTe1-x was considered. This work focuses on studying the effects of compositional variation on the conductivity of the ZnSexTe1-x films. ZnSexTe1-x films were doped using Nitrogen. Films were deposited by co-evaporation from ZnTe, ZnSe and Se sources. Te/Se ratio was varied by varying the ZnTe thickness and Se Thickness. Films with Zn/Group VI ratio close to 1 were measured for conductivity using IV measurements. Highest conductivity of 2* 10 -8 O-cm was obtained at ZnSe, ZnTe, and Se thicknesses of 2000A, 1500A, and 500A respectively. The actual carrier concentration could be concealed by the current limiting Cu contacts. All films with Zn/Group VI ratio close to 1 showed slight conductivity in the 10-10 O-cm range. Layered ZnSexTe1-x Films doped with Nitrogen had targeted Zn/Group VI ratio of 1, but with a higher Te content. The films were also slightly conductive, in the 10-10 O-cm range. The mechanism limiting the doping in all the films seems to be the same.

Vakkalanka, Sridevi A.

274

Thermal Conductances of Pressed Copper Contacts  

NASA Technical Reports Server (NTRS)

Report describes investigation of thermal conductivities of smooth copper contacts pressed together at liquid-helium temperatures. Investigation prompted by need for accurate thermal models for infrared detectors and other cryogenic instruments.

Salerno, L.; Kittel, P.; Spivak, A.

1986-01-01

275

21 CFR 73.2647 - Copper powder.  

Code of Federal Regulations, 2010 CFR

...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive copper powder shall conform...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

2010-04-01

276

21 CFR 73.2647 - Copper powder.  

Code of Federal Regulations, 2011 CFR

...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive copper powder shall conform...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

2011-04-01

277

Copper-Catalyzed Trifluoromethylation of Unactivated Olefins  

E-print Network

Activating the inactive: A copper-catalyzed allylic trifluoromethylation of unactivated terminal olefins proceeds under mild conditions to produce linear allylic trifluoromethylated products with high E/Z selectivity (see ...

Parsons, Andrew T.

278

21 CFR 184.1261 - Copper sulfate.  

Code of Federal Regulations, 2011 CFR

...granules, or as a light blue powder. The ingredient is prepared by the reaction of sulfuric acid with cupric oxide or with copper metal. (b) The ingredient must be of a purity suitable for its intended use. (c) In accordance...

2011-04-01

279

21 CFR 184.1261 - Copper sulfate.  

Code of Federal Regulations, 2012 CFR

...granules, or as a light blue powder. The ingredient is prepared by the reaction of sulfuric acid with cupric oxide or with copper metal. (b) The ingredient must be of a purity suitable for its intended use. (c) In accordance...

2012-04-01

280

21 CFR 184.1261 - Copper sulfate.  

Code of Federal Regulations, 2013 CFR

...granules, or as a light blue powder. The ingredient is prepared by the reaction of sulfuric acid with cupric oxide or with copper metal. (b) The ingredient must be of a purity suitable for its intended use. (c) In accordance...

2013-04-01

281

Copper foil provides uniform heat sink path  

NASA Technical Reports Server (NTRS)

Thermal path prevents voids and discontinuities which make heat sinks in electronic equipment inefficient. The thermal path combines the high thermal conductivity of copper with the resiliency of silicone rubber.

Phillips, I. E., Jr.; Schreihans, F. A.

1966-01-01

282

BIOCHEMISTRY: Free Copper Ions in the Cell?  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. How enzymes such as copper-zinc superoxide dismutase (SOD1), an important antioxidant enzyme in the cell, obtain the transition metal ions that they need to function is still far from understood. In Science this week, Rae et al. demonstrate that the yCCS metallochaperone in yeast inserts copper ions directly into the enzyme and is only active at very low concentrations of intracellular copper. Moreover, these investigators made the unexpected discovery that there is less than one atom of free copper per cell. A Perspective by Lippard comments on these findings and their implications for human diseases that involve dysregulation of transition metal ion intracellular concentrations or mutations in SOD1.

Stephen J. Lippard (Massachusetts Institute of Technology;Department of Chemistry)

1999-04-30

283

Characteristics and antimicrobial activity of copper-based materials  

NASA Astrophysics Data System (ADS)

In this study, copper vermiculite was synthesized, and the characteristics, antimicrobial effects, and chemical stability of copper vermiculite were investigated. Two types of copper vermiculite materials, micron-sized copper vermiculite (MCV) and exfoliated copper vermiculite (MECV), are selected for this research. Since most of the functional fillers used in industry products, such as plastics, paints, rubbers, papers, and textiles prefer micron-scaled particles, micron-sized copper vermiculite was prepared by jet-milling vermiculite. Meanwhile, since the exfoliated vermiculite has very unique properties, such as high porosity, specific surface area, high aspect ratio of laminates, and low density, and has been extensively utilized as a functional additives, exfoliated copper vermiculite also was synthesized and investigated. The antibacterial efficiency of copper vermiculite was qualitatively evaluated by the diffusion methods (both liquid diffusion and solid diffusion) against the most common pathogenic species: Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Klebsiella pneumoniae (K. pneumoniae). The result showed that the release velocity of copper from copper vermiculite is very slow. However, copper vermiculite clearly has excellent antibacterial efficiency to S. aureus, K. pneumoniae and E. coli. The strongest antibacterial ability of copper vermiculite is its action on S. aureus. The antibacterial efficiency of copper vermiculite was also quantitatively evaluated by determining the reduction rate (death rate) of E. coli versus various levels of copper vermiculite. 10 ppm of copper vermiculite in solution is sufficient to reduce the cell population of E. coli, while the untreated vermiculite had no antibacterial activity. The slow release of copper revealed that the antimicrobial effect of copper vermiculite was due to the strong interactions between copper ions and bacteria cells. Exfoliated copper vermiculite has even stronger antibacterial activity than copper vermiculite against E. coli. With 200 ppm exfoliated copper vermiculite in bacteria suspension (4.68 ppm of metal copper), the reduction of viable bacteria are 99.8% at 1 hour, and >99.9% at 2 hours. With 10 ppm exfoliated copper vermiculite in bacteria dilution (0.234 ppm of copper atoms), the reduction of viable E. coli reached 98.7% at 1 hour, and >95.6% at 2 hours. Molds have the potential to cause health problems, such as allergic reactions, irritations, and mycotoxins, and damage to buildings, historic relics, properties, etc. Since copper has better antifungal property, an initial antifungal activity of copper vermiculite was evaluated in this study. Fat-free milk was used to develop molds in the test samples by saturated samples. Incubated at 36°C for 48 hours, all of the surfaces of untreated control samples, including micron-sized vermiculite, exfoliated vermiculite, bentonite, and kaolin, have been covered by thick mold layers. However, there were no mold showed on copper vermiculite and exfoliated copper vermiculite. Even after the incubation was lasted for 10 days, copper vermiculite and exfoliated copper vermiculite did not show any mold on the surface. These results exhibited copper vermiculite has excellent antifungal activities against mold. Stability of copper ions in copper vermiculite was measured by aqueous leaching process. Copper vermiculite and exfoliated copper vermiculite were put into distilled water in a ratio of 2.0g/100ml, and then implemented leaching processes by continuously shaking (leaching) and statically storing (soaking) for desired periods of time, respectively. According to the analytic result by inductively coupled plasma spectroscopy (ICP), the major metals released were copper, magnesium, iron, silicon, and aluminum. The release rate of copper depends on the environmental conditions. Under the dynamic leaching condition, all the major elements had shown linear leaching rates, and slowly increases along with the leaching time. Copper concentration in 1 hour leached solutions had suffi

Li, Bowen

284

Ternary lanthanum sulfide selenides {alpha}-LaS{sub 2-x}Se{sub x} (0  

SciTech Connect

Mixed lanthanum sulfide selenides LaS{sub 2-x}Se{sub x} (0selenides. Highlights: Black-Right-Pointing-Pointer Vegard series of mixed lanthanum sulfide selenides LaS{sub 2-x}Se{sub x} (0

Bartsch, Christian [Department of Chemistry and Food Chemistry, Technische Universitaet Dresden, D-01062 Dresden (Germany); Doert, Thomas, E-mail: thomas.doert@chemie.tu-dresden.de [Department of Chemistry and Food Chemistry, Technische Universitaet Dresden, D-01062 Dresden (Germany)

2012-01-15

285

Effects of Layer Double Hydroxide Nanoclays on the Toxicity of Copper to Daphnia Magna.  

E-print Network

??Nanoparticles may affect secondary pollutants such as copper. Layer Double Hydroxides (LDH) are synthetically produced nanoparticles that adsorb copper via cation exchange. Pretreatment of copper… (more)

Blake, Deanne Renee

2012-01-01

286

40 CFR 468.20 - Applicability; description of the beryllium copper forming subcategory.  

...Applicability; description of the beryllium copper forming subcategory. ...FORMING POINT SOURCE CATEGORY Beryllium Copper Forming Subcategory ...Applicability; description of the beryllium copper forming...

2014-07-01

287

Copper transport and compartmentation in grape cells.  

PubMed

Copper-based fungicides have been widely used against several grapevine (Vitis vinifera L.) diseases since the late 1800s when the Bordeaux mixture was developed, but their intensive use has raised phytotoxicity concerns. In this study, physiological, biochemical and molecular approaches were combined to investigate the impacts of copper in grape cells and how it is transported and compartmented intracellularly. Copper reduced the growth and viability of grape cells (CSB, Cabernet Sauvignon Berry) in a dose-dependent manner above 100 µM and was accumulated in specific metal ion sinks. The copper-sensitive probe Phen Green SK was used to characterize copper transport across the plasma membrane of CSB cells. The transport system (K(m) = 583 µM; V(max) = 177 × 10(-6) %?F min(-1) protoplast(-1)) was regulated by copper availability in the culture medium, stimulated by Ca(2+) and inhibited by Zn(2+). The pH-sensitive fluorescent probe ACMA (9-amino-6-chloro-2-methoxyacridine) was used to evaluate the involvement of proton-dependent copper transport across the tonoplast. Cu(2+) compartmentation in the vacuole was dependent on the transmembrane pH gradient generated by both V-H(+)-ATPase and V-H(+)-pyrophosphatase (PPase). High copper levels in the growth medium did not affect the activity of V-H(+)-PPase but decreased the magnitude of the H(+) gradient generated by V-H(+)-ATPase. Expression studies of VvCTr genes showed that VvCTr1 and VvCTr8 were distinctly affected by CuSO(4) availability in grape cell cultures and that both genes were highly expressed in the green stage of grape berries. PMID:22952251

Martins, Viviana; Hanana, Mohsen; Blumwald, Eduardo; Gerós, Hernâni

2012-11-01

288

Oxide dispersed copper alloys by surface oxidation  

Microsoft Academic Search

A series of Cu-Al and Cu-Ni-Al alloys, inert gas atomized, as -44 ? powders, were converted to submicron thick flakes covered\\u000a by copper oxide and aluminum oxide in varying amounts, depending on the initial aluminum content. The flake powders were either\\u000a hydrogen reduced to eliminate copper oxide, or were reacted in a hot inert gas to increase the Al2O3 content

William F. Schilling; Nicholas J. Grant

1970-01-01

289

Oxide dispersed copper alloys by surface oxidation  

Microsoft Academic Search

A series of Cu-Al and Cu-Ni-Al alloys, inert gas atomized, as -44 mu powders, were converted to submicron thick flakes covered by copper oxide and aluminum oxide in varying amounts, depending on the initial aluminum content. The flake powders were either hydrogen reduced to eliminate copper oxide, or were reacted in a hot inert gas to increase the Al2O3 content

William F. Schilling; Nicholas J. Grant

1970-01-01

290

Copper metallization for ULSL and beyond  

Microsoft Academic Search

The investigation of copper for use as an interconnection metal in the ultra large-scale integration (ULSI) era of silicon integrated circuits has accelerated in the past several years. The obvious advantages for using copper to replace currently used Al are related to its lower resistivity (1.7 ??-cm vs. 2.7 ??-cm for Al) and its higher electromigration resistance (several orders of

Shyam P. Murarka; Steven W. Hymes

1995-01-01

291

APPLICATIONS OF LASERS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Optical strength of the surface of zinc selenide subjected to single and repeated interaction with radiation from a pulsed CO2 laser  

NASA Astrophysics Data System (ADS)

A considerable difference was found between the dependences of the optical damage threshold of the surface of zinc selenide on the area of the irradiated spot when single CO2 laser pulses were used and when the surface was exposed repeatedly to such pulses. Electron microscopy was used to identify the characteristic types of damage. The experimental results were explained on the basis of the probabilistic nature of the presence of defects with a lower evaporation threshold in the irradiation zone using a theory of thermoelastic interaction of pulsed laser radiation with the surfaces of solids.

Kolesnikov, N. N.; Konov, Vitalii I.; Kulakov, M. P.; Pimenov, S. M.; Starodumov, Yu M.; Chapliev, N. I.

1987-07-01

292

Sorption of copper by vegetated copper-mine tailings  

NASA Astrophysics Data System (ADS)

The lixiviation of copper (Cu) from vegetated mine tailings may present an environmental risk because of the potential adverse effects it may pose to ground and surface water around mines. However, bonding of Cu to mine tailings can limit transfer to surrounding water. The main objective of the present study is to assess Cu sorption by cultivated Cu-mine tailings containing calcite (pH 7.7) as influenced by commercial peat moss-shrimp waste compost (PSC) and chelating solution. Fresh tailing and tailing that had been used in pot experiments were tested and compared. Samples (0.50 g) of tailings were equilibrated with 20 cm3 of 0.01 M CaCl2 solution containing 100 mg Cu dm-3, as CuCl2, for 72 h at room temperature. After equilibration period, the samples were centrifuged and filtered. Concentration of Cu in the equilibrium solution was measured by atomic absorption spectrophotometry. The sorption coefficient (Ks) was used to interpret the sorption data. The sorption experiment was replicated two times. Compost was the most effective organic amendment in enhancing Cu sorption. The Ks values were positively and significantly correlated with organic matter content and Cu associated with the organic fraction of tailing samples. The mineralogy and organic matter content can influence the sorption capacity of Cu-mine tailings. Calcite-containing mine tailings amended with PSC can be used to sorb Cu from chloride solutions.

de Coninck, A.; Karam, A.; Jaouich, A.

2009-04-01

293

Copper-resistant bacteria enhance plant growth and copper phytoextraction.  

PubMed

In this study, we investigated the role of rhizospheric bacteria in solubilizing soil copper (Cu) and promoting plant growth. The Cu-resistant bacterium DGS6 was isolated from a natural Cu-contaminated soil and was identified as Pseudomonas sp. DGS6. This isolate solubilized Cu in Cu-contaminated soil and stimulated root elongation of maize and sunflower. Maize was more sensitive to inoculation with DGS6 than was sunflower and exhibited greater root elongation. In pot experiment, inoculation with DGS6 increased the shoot dry weight of maize by 49% and sunflower by 34%, and increased the root dry weight of maize by 85% and sunflower by 45%. Although the concentrations of Cu in inoculated and non-inoculated seedlings did not differ significantly, the total accumulation of Cu in the plants increased after inoculation. DGS6 showed a high ability to solubilize P and produce iron-chelating siderophores, as well as significantly improved the accumulation of P and Fe in both maize and sunflower shoots. In addition, DGS6 produced indole-3-acetic acid (IAA) and ACC deaminase, which suggests that it may modulate ethylene levels in plants. The bacterial strain DGS6 could be a good candidate for re-vegetation of Cu-contaminated sites. Supplemental materials are available for this article. Go to the publisher's online edition of International Journal of Phytoremediation to view the supplemental file. PMID:23819298

Yang, Renxiu; Luo, Chunling; Chen, Yahua; Wang, Guiping; Xu, Yue; Shen, Zhenguo

2013-01-01

294

Copper stable isotopes to trace copper behavior in wetland systems.  

PubMed

Wetlands are reactive zones of the landscape that can sequester metals released by industrial and agricultural activities. Copper (Cu) stable isotope ratios (?(65)Cu) have recently been used as tracers of transport and transformation processes in polluted environments. Here, we used Cu stable isotopes to trace the behavior of Cu in a stormwater wetland receiving runoff from a vineyard catchment (Alsace, France). The Cu loads and stable isotope ratios were determined in the dissolved phase, suspended particulate matter (SPM), wetland sediments, and vegetation. The wetland retained >68% of the dissolved Cu and >92% of the SPM-bound Cu, which represented 84.4% of the total Cu in the runoff. The dissolved Cu became depleted in (65)Cu when passing through the wetland (?(65)Cuinlet-outlet from 0.03‰ to 0.77‰), which reflects Cu adsorption to aluminum minerals and organic matter. The ?(65)Cu values varied little in the wetland sediments (0.04 ± 0.10‰), which stored >96% of the total Cu mass within the wetland. During high-flow conditions, the Cu flowing out of the wetland became isotopically lighter, indicating the mobilization of reduced Cu(I) species from the sediments and Cu reduction within the sediments. Our results demonstrate that the Cu stable isotope ratios may help trace Cu behavior in redox-dynamic environments such as wetlands. PMID:24787375

Babcsányi, Izabella; Imfeld, Gwenaël; Granet, Mathieu; Chabaux, François

2014-05-20

295

[Photometric determination of copper content in the liver during experimental chronic copper poisoning in sheep].  

PubMed

15 castrated rams were exposed to an oral copper-dosage of 3.64 mg/d/kg body weight for 84 days. The control group consisted of 11 rams with a copper intake of 0.14 mg/d/kg bodyweight. Liver biopsies were taken percutaneously (100 samples), under laparoscopic control (53 samples) or post mortem (14 samples) before, during and up to 200 days after the controlled copper intake. Analysis of copper concentration in the liver tissue was done by a modified photometrical Bathocuproin-method after cold extraction with hydrochloric and trichloracetic acid. By using a parallel specimen blank with added EDTA, disturbing factors of the sample matrix were eliminated. The method was evaluated by the atom-absorption-spectroscopy after wet incineration as well as by standard addition of copper titrisol. The correlation with the reference method was very good (r > 0.99); the recovery rate after standard addition was 95 +/- 5.4%. The maximum copper concentrations in the liver were reached after the completion of the copper dosage. Blackheaded sheep showed significantly higher values (480 +/- 173 mg/kg wet tissue weight) than Merino sheep (338 +/- 103). The values of the control animals were 36 +/- 18 mg/kg. In the copper dosed rams the course of copper storage in the liver tissue could be described by an multiple regression with an accuracy of r2 > 0.75. The half-life of the copper concentration in the liver after exceeding maximum levels was 175 +/- 91 days. The pathogenetic role of the copper retention in the dosed animals was proven by regularly increased values of the hepatocellular enzyme glutamate dehydrogenase in the plasma. PMID:9471415

Bickhardt, K; Humann, E; Schwert, B; Coenen, M

1997-11-01

296

Cellular glutathione plays a key role in copper uptake mediated by human copper transporter 1.  

PubMed

Copper is an essential micronutrient. Following entry via the human copper transporter 1 (hCTR1), copper is delivered to several copper chaperones, which subsequently transfer the metal to specific targets via protein:protein interactions. It is has been assumed, but not demonstrated, that chaperones acquire copper directly from hCTR1. However, some reports have pointed to an intermediary role for glutathione (GSH), an abundant copper-binding tri-peptide. To address the issue of how transported copper is acquired by the copper chaperones in vivo, we measured the initial rate of (64)Cu uptake in cells in which the cellular levels of copper chaperones or GSH were substantially depleted or elevated. Knockdown or overexpression of copper chaperones ATOX1, CCS, or both had no effect on the initial rate of (64)Cu entry into HEK293 cells having endogenous or overexpressed hCTR1. In contrast, depleting cellular GSH using L-buthionine-sulfoximine (BSO) caused a 50% decrease in the initial rate of (64)Cu entry in HEK293 cells and other cell types. This decrease was reversed by washout of BSO or GSH replenishment with a permeable ester. BSO treatment under our experimental conditions had no significant effects on the viability, ATP levels, or metal content of the cells. Attenuated (64)Cu uptake in BSO was not due to oxidation of the cysteine in the putative metal-binding motif (HCH) at the intracellular hCTR1 COOH terminus, because a mutant lacking this motif was fully active, and (64)Cu uptake was still reduced by BSO treatment. Our data suggest that GSH plays an important role in copper handling at the entry step. PMID:23426973

Maryon, Edward B; Molloy, Shannon A; Kaplan, Jack H

2013-04-15

297

Regulation of copper transporter 2 expression by copper and cisplatin in human ovarian carcinoma cells.  

PubMed

Down-regulation of copper transporter 1 (CTR1) reduces uptake and sensitivity, whereas down-regulation of CTR2 enhances both. Cisplatin (DDP) triggers the rapid degradation of CTR1 and thus limits its own accumulation. We sought to determine the effect of DDP and copper on the expression of CTR2. Changes in CTR1 and CTR2 mRNA and protein levels in human ovarian carcinoma 2008 cells and ATOX1(+/+) and ATOX1(-/-) mouse embryo fibroblasts in response to exposure to DDP and copper were measured by quantitative reverse transcriptase-polymerase chain reaction, Western blot analysis, and deconvolution microscopy. DDP triggered rapid degradation of CTR1 in 2008 human ovarian cancer cells. However, it increased the expression of CTR2 mRNA and protein levels. Expression of CTR2 was heavily modulated by changes in intracellular copper concentration; copper depletion produced rapid disappearance of CTR2, whereas excess copper increased the level of CTR2 protein. This increase was associated with an increase in CTR2 mRNA and prolongation of the CTR2 half-life. Consistent with prior observations that short hairpin RNA interference-mediated knockdown of CTR2 enhanced DDP uptake and tumor cell kill, reduction of CTR2 by copper starvation also enhanced DDP uptake and cytotoxicity. Comparison of the ability of copper and DDP to modulate the expression of CTR1 in ATOX1(+/+) and ATOX1(-/-) indicated that ATOX1 participates in the regulation of CTR2 expression. Unlike CTR1, the expression of CTR2 is increased rather than decreased by DDP. Therefore, these two copper transporters have opposite effects on DDP sensitivity. CTR2 expression is regulated by copper availability via the copper-dependent regulator ATOX1. PMID:20194531

Blair, Brian G; Larson, Christopher A; Adams, Preston L; Abada, Paolo B; Safaei, Roohangiz; Howell, Stephen B

2010-06-01

298

Cellular glutathione plays a key role in copper uptake mediated by human copper transporter 1  

PubMed Central

Copper is an essential micronutrient. Following entry via the human copper transporter 1 (hCTR1), copper is delivered to several copper chaperones, which subsequently transfer the metal to specific targets via protein:protein interactions. It is has been assumed, but not demonstrated, that chaperones acquire copper directly from hCTR1. However, some reports have pointed to an intermediary role for glutathione (GSH), an abundant copper-binding tri-peptide. To address the issue of how transported copper is acquired by the copper chaperones in vivo, we measured the initial rate of 64Cu uptake in cells in which the cellular levels of copper chaperones or GSH were substantially depleted or elevated. Knockdown or overexpression of copper chaperones ATOX1, CCS, or both had no effect on the initial rate of 64Cu entry into HEK293 cells having endogenous or overexpressed hCTR1. In contrast, depleting cellular GSH using l-buthionine-sulfoximine (BSO) caused a 50% decrease in the initial rate of 64Cu entry in HEK293 cells and other cell types. This decrease was reversed by washout of BSO or GSH replenishment with a permeable ester. BSO treatment under our experimental conditions had no significant effects on the viability, ATP levels, or metal content of the cells. Attenuated 64Cu uptake in BSO was not due to oxidation of the cysteine in the putative metal-binding motif (HCH) at the intracellular hCTR1 COOH terminus, because a mutant lacking this motif was fully active, and 64Cu uptake was still reduced by BSO treatment. Our data suggest that GSH plays an important role in copper handling at the entry step. PMID:23426973

Maryon, Edward B.; Molloy, Shannon A.

2013-01-01

299

Diorganotin(IV) 2-pyridyl selenolates: synthesis, structures and their utility as molecular precursors for the preparation of tin selenide nanocrystals and thin films.  

PubMed

Reactions of R(2)SnCl(2) (R = Me, Et, (t)Bu) with NaSeC(5)H(3)(R'-3)N (R' = H or Me) gave complexes of the composition [R(2)Sn{2-SeC(5)H(3)(R'-3)N)}(2)], which on treatment with R(2)SnCl(2) afforded chloro complexes, [R(2)Sn{2-SeC(5)H(3)(R'-3)N}Cl]. These complexes were characterized by elemental analyses and UV-vis and NMR ((1)H, (13)C, (77)Se and (119)Sn) spectroscopy. The crystal structures of [R(2)Sn(SeC(5)H(4)N)(2)] (R = Me or (t)Bu) and [Me(2)Sn{2-SeC(5)H(3)(Me-3)N}Cl] were determined by single crystal X-ray diffraction. The tin atom in the former two structures acquires a skew trapezoidal configuration, whereas in the latter it adopts a distorted trigonal bipyramidal geometry. Thermolysis of [R(2)Sn(2-SeC(5)H(4)N)(2)] (R = Me, Et or (t)Bu) and [Et(2)Sn{2-SeC(5)H(3)(Me-3)N}(2)] in oleylamine (OA) afforded tin selenide nanostructures. Thin films of SnSe were deposited on glass and silicon substrates by the AACVD of [(t)Bu(2)Sn(2-SeC(5)H(4)N)(2)]. The nanostructures and thin films were characterized by XRD, EDX, AFM, SEM, TEM and SAED techniques. The photovoltaic properties of the thin films have been evaluated. PMID:22918450

Sharma, Rakesh K; Kedarnath, G; Wadawale, Amey; Betty, C A; Vishwanadh, B; Jain, Vimal K

2012-10-21

300

Electronic Characterization of Defects in Narrow Gap Semiconductors-Comparison of Electronic Energy Levels and Formation Energies in Mercury Cadmium Telluride, Mercury Zinc Telluride, and Mercury Zinc Selenide  

NASA Technical Reports Server (NTRS)

We have used a Green's function technique to calculate the energy levels and formation energy of deep defects in the narrow gap semiconductors mercury cadmium telluride (MCT), mercury zinc telluride (MZT) and mercury zinc selenide (MZS). The formation energy is calculated from the difference between the total energy with an impurity cluster and the total energy for the perfect crystal. Substitutional (including antisite), interstitial (self and foreign), and vacancy deep defects are considered. Relaxation effects are calculated (with molecular dynamics). By use of a pseudopotential, we generalize the ideal vacancy model so as to be able to consider relaxation for vacancies. Different charge states are considered and the charged state energy shift (as computed by a modified Haldane-Anderson model) can be twice that due to relaxation. Different charged states for vacancies were not calculated to have much effect on the formation energy. For all cases we find deep defects in the energy gap only for cation site s-like orbitals or anion site p-like orbitals, and for the substitutional case only the latter are appreciably effected by relaxation. For most cases for MCT, MZT, MZS, we consider x (the concentration of Cd or Zn) in the range appropriate for a band gap of 0.1 eV. For defect energy levels, the absolute accuracy of our results is limited, but the precision is good, and hence chemical trends are accurately predicted. For the same reason, defect formation energies are more accurately predicted than energy level position. We attempt, in Appendix B, to calculate vacancy formation energies using relatively simple chemical bonding ideas due to Harrison. However, these results are only marginally accurate for estimating vacancy binding energies. Appendix C lists all written reports and publications produced for the grant. We include abstracts and a complete paper that summarizes our work which is not yet available.

Patterson, James D.

1996-01-01

301

Structural, magnetic, and electronic properties of iron selenide Fe6-7Se8 nanoparticles obtained by thermal decomposition in high-temperature organic solvents.  

PubMed

Iron selenide nanoparticles with the NiAs-like crystal structure were synthesized by thermal decomposition of iron chloride and selenium powder in a high-temperature organic solvent. Depending on the time of the compound processing at 340?°C, the nanocrystals with monoclinic (M)-Fe3Se4 or hexagonal (H)-Fe7Se8 structures as well as a mixture of these two phases can be obtained. The magnetic behavior of the monoclinic and hexagonal phases is very different. The applied-field and temperature dependences of magnetization reveal a complicated transformation between ferrimagnetic (FRM) and antiferromagnetic (AFM) structures, which can be related to the spin rotation process connected with the redistribution of cation vacancies. From XRD and Mössbauer data, the 3c type superstructure of vacancy ordering was found in the hexagonal Fe7Se8. Redistribution of vacancies in Fe7Se8 from random to ordered leads to the transformation of the magnetic structure from FRM to AFM. The Mössbauer data indicate that vacancies in the monoclinic Fe3Se4 prefer to appear near the Fe(3+) ions and stimulate the magnetic transition with the rotation of the Fe(3+) magnetic moments. Unusually high coercive force Hc was found in both (H) and (M) nanocrystals with the highest ("giant") value of about 25 kOe in monoclinic Fe3Se4. This is explained by the strong surface magnetic anisotropy which is essentially larger than the core anisotropy. Such a large coercivity is rare for materials without rare earth or noble metal elements, and the Fe3Se4-based compounds can be the low-cost, nontoxic alternative materials for advanced magnets. In addition, an unusual effect of "switching" of magnetization in a field of 10 kOe was found in the Fe3Se4 nanoparticles below 280 K, which can be important for applications. PMID:25084934

Lyubutin, I S; Lin, Chun-Rong; Funtov, K O; Dmitrieva, T V; Starchikov, S S; Siao, Yu-Jhan; Chen, Mei-Li

2014-07-28

302

Structural, magnetic, and electronic properties of iron selenide Fe6-7Se8 nanoparticles obtained by thermal decomposition in high-temperature organic solvents  

NASA Astrophysics Data System (ADS)

Iron selenide nanoparticles with the NiAs-like crystal structure were synthesized by thermal decomposition of iron chloride and selenium powder in a high-temperature organic solvent. Depending on the time of the compound processing at 340 °C, the nanocrystals with monoclinic (M)-Fe3Se4 or hexagonal (H)-Fe7Se8 structures as well as a mixture of these two phases can be obtained. The magnetic behavior of the monoclinic and hexagonal phases is very different. The applied-field and temperature dependences of magnetization reveal a complicated transformation between ferrimagnetic (FRM) and antiferromagnetic (AFM) structures, which can be related to the spin rotation process connected with the redistribution of cation vacancies. From XRD and Mössbauer data, the 3c type superstructure of vacancy ordering was found in the hexagonal Fe7Se8. Redistribution of vacancies in Fe7Se8 from random to ordered leads to the transformation of the magnetic structure from FRM to AFM. The Mössbauer data indicate that vacancies in the monoclinic Fe3Se4 prefer to appear near the Fe3+ ions and stimulate the magnetic transition with the rotation of the Fe3+ magnetic moments. Unusually high coercive force Hc was found in both (H) and (M) nanocrystals with the highest ("giant") value of about 25 kOe in monoclinic Fe3Se4. This is explained by the strong surface magnetic anisotropy which is essentially larger than the core anisotropy. Such a large coercivity is rare for materials without rare earth or noble metal elements, and the Fe3Se4-based compounds can be the low-cost, nontoxic alternative materials for advanced magnets. In addition, an unusual effect of "switching" of magnetization in a field of 10 kOe was found in the Fe3Se4 nanoparticles below 280 K, which can be important for applications.

Lyubutin, I. S.; Lin, Chun-Rong; Funtov, K. O.; Dmitrieva, T. V.; Starchikov, S. S.; Siao, Yu-Jhan; Chen, Mei-Li

2014-07-01

303

Attempted induction of chronic copper poisoning in boma confined impala.  

PubMed

Induction of chronic copper poisoning in ten boma-confined impala was attempted in a randomized, single dose, parallel designed, titration study using five increasing oral doses, ranging between 125 mg/kg to 1000 mg/kg, of copper oxide needles. Two untreated impala were kept as controls. Impala (n = 1) from each treatment group were culled 52 d and 105 d after treatment and examined for tissue copper accumulation and signs of chronic copper poisoning. Despite the high doses of copper administered to the impala and liver copper concentrations above 150 ppm WM achieved in two animals, no clinical signs related to chronic copper poisoning were observed. Faecal copper concentrations indicated that the major portion of copper oxide particles was excreted in the faeces. PMID:10631706

Grobler, D G; Swan, G E

1999-09-01

304

Method for providing uranium with a protective copper coating  

DOEpatents

The present invention is directed to a method for providing uranium metal with a protective coating of copper. Uranium metal is subjected to a conventional cleaning operation wherein oxides and other surface contaminants are removed, followed by etching and pickling operations. The copper coating is provided by first electrodepositing a thin and relatively porous flash layer of copper on the uranium in a copper cyanide bath. The resulting copper-layered article is then heated in an air or inert atmosphere to volatilize and drive off the volatile material underlying the copper flash layer. After the heating step an adherent and essentially non-porous layer of copper is electro-deposited on the flash layer of copper to provide an adherent, multi-layer copper coating which is essentially impervious to corrosion by most gases.

Waldrop, Forrest B. (Powell, TN); Jones, Edward (Knoxville, TN)

1981-01-01

305

Manganese, copper and copper enzymes in blood of Icelandic sheep: Relevance to scrapie  

Microsoft Academic Search

The aim of this study was to investigate whether amounts of manganese or copper in blood, or the activity of copper enzymes (ceruloplasmin oxidative activity in serum and superoxide dismutase (SOD1) activity in erythrocytes) could be related to the sporadic occurrence of scrapie on sheep farms in Iceland. The farms were divided into three Categories: Category 1: scrapie-free (never afflicted

TORKELL JÓHANNESSON; KRISTÍN BJÖRG GUDMUNDSDÓTTIR; JED BARASH; JAKOB KRISTINSSON; TRYGGVI EIRÍKSSON; SIGURDUR SIGURDARSON

306

Copper intake and health threat by consuming seafood from copper-contaminated coastal environments in Taiwan  

SciTech Connect

The purpose of this paper is to describe the impact of copper pollution on the main aquaculture coast of Taiwan and the potential risk from eating the green oysters cultured along the polluted coast. The data show that the highest average concentration of copper in oysters was observed in the Erhjin Chi estuary from 1986 to 1990. The copper concentration in both the seawater and the sediment collected along the Erhjin Chi estuary was also the highest in all sampling locations. Copper concentration in oysters collected from Erhjin Chi, Hsiangshan, and Anping from 1988 to 1990 was, respectively, 61, 29, and 22 times higher than that of 10 years ago. The potential frisk from consuming oysters is relatively higher than that of other seafoods due the high bioaccumulation of oysters. The oysters in the Erhjin Chi estuary had an average concentration of copper of 3,075 [+-] 826 [mu]g/g during the past three years (1988--1990). The average copper intake from oysters for an adult with 70 kg body weight was 12.6 mg/d. The estimate indicated that the average copper intake from the oysters for female individuals is 14 times more than that of international limits. Based on the average value, long-term intake of copper through consumption of oysters cultured along the Erhjin Chi estuary be critical, especially for some high-risk groups.

Han, B.C. (Taipei Medical Coll. (Taiwan, Province of China). School of Public Health); Jeng, W.L.; Hung, T.C. (National Taiwan Univ., Taipei (Taiwan, Province of China). Inst. of Oceanography); Jeng, M.S. (Academia Sinica, Taipei (Taiwan, Province of China). Inst. of Zoology)

1994-05-01

307

Copper reduction by copper binding proteins and its relation to neurodegenerative diseases  

Microsoft Academic Search

Increasing evidence supports an important role for metals in neurobiology. In fact, copper binding proteins that form bioinorganic complexes are able to display oxidant or anti-oxidant properties, which would impact on neuronal function or in the triggering of neurodegenerative process. Two proteins related to neurodegenerative diseases have been described as copper binding proteins: the amyloid precursor protein (APP), a protein

Carlos Opazo; María Inés Barría; Francisca H. Ruiz; Nibaldo C. Inestrosa

2003-01-01

308

Independent Evolution of Heavy Metal-Associated Domains in Copper Chaperones and Copper-Transporting ATPases  

E-print Network

Independent Evolution of Heavy Metal-Associated Domains in Copper Chaperones and Copper and structure to the Cu- binding heavy metal-associated (HMA) domains of Cu- transporting ATPases (Cu to the Cu-binding heavy metal-associated (HMA) domains of Cu-transporting ATPases (Cu- ATPases) whose genes

Jordan, King

309

Heme/copper terminal oxidases  

SciTech Connect

Spatially well-organized electron-transfer reactions in a series of membrane-bound redox proteins form the basis for energy conservation in both photosynthesis and respiration. The membrane-bound nature of the electron-transfer processes is critical, as the free energy made available in exergonic redox chemistry is used to generate transmembrane proton concentration and electrostatic potential gradients. These gradients are subsequently used to drive ATP formation, which provides the immediate energy source for constructive cellular processes. The terminal heme/copper oxidases in respiratory electron-transfer chains illustrate a number of the thermodynamic and structural principles that have driven the development of respiration. This class of enzyme reduces dioxygen to water, thus clearing the respiratory system of low-energy electrons so that sustained electron transfer and free-energy transduction can occur. By using dioxygen as the oxidizing substrate, free-energy production per electron through the chain is substantial, owing to the high reduction potential of O{sub 2} (0.815 V at pH 7). 122 refs.

Ferguson-Miller, S.; Babcock, G.T. [Michigan State Univ., East Lansing, MI (United States)] [Michigan State Univ., East Lansing, MI (United States)

1996-11-01

310

Metal (copper) segregation in magmas  

NASA Astrophysics Data System (ADS)

Before precipitating to form porphyry-type deposits, metals are transported and concentrated into magmas. Ultimately, they can enter crystalline phases or segregate into the volatile phase. In both cases, partition coefficients determine the partitioning according to the ambient physico-chemical conditions. Metal partitioning between the melt and the magmatic volatile phase (MVP) is driven by their solubility. In this study, Cu has been selected as a test for metal segregation. We evaluate qualitatively the metal's behavior with respect to the melt or to the MVP by comparing the difference in chemical potential and polarizability between the fluid phase and dissolved copper compound. Maps of polarizability are drawn after computing the chemical reactivity parameters (electrophilicity, hardness, and polarizability) for various silicate melts; a synthetic fluid phase with water, CO2, S18 compounds and halogens; and Cu-compounds as a test metal. Cu-compounds show a better affinity with the fluid phase, enhanced by the presence of S in its reduced form. It explains how Cu could segregate into the fluid phase at the magmatic stage before being enriched by diffusion or melt/vapor partitioning, leading to late hydrothermal precipitation. The method should therefore be considered as a model for understanding the behavior of other metals and their segregation during the magmatic stage.

Vigneresse, Jean-Louis; Truche, Laurent; Chattaraj, Pratim K.

2014-11-01

311

Phototunable Magnetism in Copper Octacyanomolybdate  

PubMed Central

We introduce copper molybdenum cyanides of general formula Cu2[Mo(CN)8]·nH2O, which can serve as optofunctional magnetic devices. Their ground states generally stay paramagnetic down to temperatures of the K order but exhibit a spontaneous magnetization upon photoirradiation usually below a few tens of K. To interest us still further, such a ferromagnetic stateinduced by blue-laser irradiation is demagnetized step by step through further application of red or near-infrared laser pulses. We solve this intriguing photomagnetism. The ground-state properties are fully revealed by means of a group-theoretical technique. Taking account of experimental observations, we simulate applying pump laser pulses to a likely ground state and successfully reproduce both the magnetization and demagnetization dynamics. We monitor the photorelaxation process through angle-resolved photoemission spectroscopy. Electrons are fully itinerant in any of the photoinduced steady states, forming a striking contrast to the initial equilibrium state of atomic aspect. The fully demagnetized final steady state looks completely different from the initial paramagnetism but bears good analogy to one of the possible ground states available with the Coulomb repulsion on Cu sites suppressed. PMID:24895661

Ohara, Jun

2014-01-01

312

Magnetic field effects on copper metal deposition from copper sulfate aqueous solution.  

PubMed

Effects of a magnetic field (?0.5 T) on electroless copper metal deposition from the reaction of a copper sulfate aqueous solution and a zinc thin plate were examined in this study. In a zero field, a smooth copper thin film grew steadily on the plate. In a 0.38 T field, a smooth copper thin film deposited on a zinc plate within about 1 min. Then, it peeled off repeatedly from the plate. The yield of consumed copper ions increased about 2.1 times compared with that in a zero field. Mechanism of this magnetic field effect was discussed in terms of Lorentz force- and magnetic force-induced convection and local volta cell formation. PMID:24738491

Udagawa, Chikako; Maeda, Aya; Katsuki, Akio; Maki, Syou; Morimoto, Shotaro; Tanimoto, Yoshifumi

2014-05-01

313

Enhanced ATP-dependent copper efflux across the root cell plasma membrane in copper-tolerant Silene vulgaris.  

PubMed

We studied copper uptake in inside-out plasma membrane vesicles derived from roots of copper-sensitive, moderately copper-tolerant and highly copper-tolerant populations of Silene vulgaris (Amsterdam, Marsberg and Imsbach, respectively). Plasma membrane vesicles were isolated using the two-phase partitioning method and copper efflux was measured using direct filtration experiments. Vesicles derived from Imsbach plants accumulated two and three times more copper than those derived from Marsberg and Amsterdam plants, respectively. This accumulation was ATP-dependent. Also, 9-amino-6-chloro-2-methoxyacridine fluorescence quenching rates upon copper addition decreased in the order Imsbach>Marsberg>Amsterdam. Our results support the hypothesis that efflux of copper across the root plasma membrane plays a role in the copper tolerance mechanism in S. vulgaris. PMID:12060300

Van Hoof, Nathalie A. L. M.; Koevoets, Paul L. M.; Hakvoort, Henk W. J.; Ten Bookum, Wilma M.; Schat, Henk; Verkleij, Jos A. C.; Ernst, Wilfried H. O.

2001-10-01

314

Copper in microbial pathogenesis: meddling with the metal  

PubMed Central

Transition metals such as iron, zinc, copper and manganese are essential for the growth and development of organisms ranging from bacteria to mammals. Numerous studies have focused on the impact of iron availability during bacterial and fungal infections, and increasing evidence suggests that copper is also involved in microbial pathogenesis. Not only is copper an essential co-factor for specific microbial enzymes, but several recent studies also strongly suggest that copper is used to restrict pathogen growth in vivo. Here, we review evidence that animals use copper as an anti-microbial weapon and, in turn, microbes have developed mechanisms to counteract the toxic effects of copper. PMID:22341460

Samanovic, Marie I.; Ding, Chen; Thiele, Dennis J.; Darwin, K. Heran

2012-01-01

315

Copper and oxidative stress in the pathogenesis of Alzheimer's disease.  

PubMed

Copper is a redox-active metal with many important biological roles. Consequently, its distribution and oxidation state are subject to stringent regulation. A large body of clinicopathological, circumstantial, and epidemiological evidence suggests that the dysregulation of copper is intimately involved in the pathogenesis of Alzheimer's disease. Other light transition metals such as iron and zinc may affect copper regulation by competing for copper binding sites and transporters. Therapeutic interventions targeting the regulation of copper are promising, but large gaps in our understanding of copper biochemistry, amyloidogenesis, and the nature of oxidative stress in the brain must be addressed. PMID:22708607

Eskici, Gözde; Axelsen, Paul H

2012-08-14

316

Growth, copper-tolerant cells, and extracellular protein production in copper-stressed chemostat cultures of Vibrio alginolyticus.  

PubMed Central

The influence of elevated copper concentrations on cell numbers and extracellular protein production was investigated in chemostat cultures of Vibrio alginolyticus. High (20 microM) copper in the medium reservoir resulted in a dramatic drop in cell numbers which was overcome with time. The copper-stressed cultures established a new equilibrium cell concentration slightly (ca. 20%) lower than control cultures. Copper-stressed chemostat populations contained an increased number of copper-resistant cells, but these averaged only 26% of the copper-adapted population. Previously copper-stressed populations exhibited resistance to a second challenge with copper. Proteins with properties identical to those of copper-induced, copper-binding proteins (CuBPs) observed in batch cultures of V. alginolyticus were observed in the supernatants of copper-stressed chemostat cultures and not in controls. CuBPs from batch and chemostat cultures were identical in terms of their induction by copper, molecular weight, and retention volumes on both immobilized copper ion-affinity chromatography and reverse-phase high-performance liquid chromatography columns. The concentration of CuBP in the chemostat was dependent on copper concentration in the medium reservoir. Either one or two forms of CuBP were observed in various analyses from both batch and chemostat cultures. Gel-to-gel variability was implicated as a factor determining whether one or two forms were resolved in a given analysis.(ABSTRACT TRUNCATED AT 250 WORDS) Images PMID:8439167

Gordon, A S; Harwood, V J; Sayyar, S

1993-01-01

317

Corrosion of a new copper-gold or copper-platinum intrauterine device.  

PubMed

It has been shown previously that supplementing plastic intrauterine devices (IUDs) with copper wire enhances the antifertility effect of the device. The use of copper intrauterine contraceptive devices, however, is currently limited to two to three years, mainly because of wire fragmentation, which was observed as early as after eight months of use. In the resulting search for a long-lasting device, two new systems of duplex wire, with gold and platinum cores electrolytically coated with copper, were devised and studied. Initially, duplex wires and controls were exposed to physiological solution. Copper dissolution rate and corrosion morphology were studied by weight-loss measurements and optical metallography. Similar systems were then surgically implanted in rat uteri for varying periods of up to 26 weeks. Electron microanalysis of corrosion products, in addition to weight-loss measurements and metallography, was performed. The results showed that a uniform and ductile copper coating is obtainable by electroplating on gold and platinum wires. Rate of copper dissolution is similar to that of solid copper wire. No dissolution of gold and platinum in the controls or coated wires was detected by weight loss, metallography, or atomic absorption measurements. Microanalysis of the deposits and corrosion products on the wires in the uteri environment showed sulfur, chlorine, and calcium, in addition to copper. The results of this study suggest that supplementing IUDs with copper-coated gold or platinum wires may result in significant prolongation of the life span of the device by preventing uncontrolled loss of copper caused by wire fragmentation. PMID:7174708

Gal-Or, L; Gonen, R; Zilberman, A; Scharf, M

1982-11-01

318

Evolution of Copper Transporting ATPases in Eukaryotic Organisms  

PubMed Central

Copper is an essential nutrient for most life forms, however in excess it can be harmful. The ATP-driven copper pumps (Copper-ATPases) play critical role in living organisms by maintaining appropriate copper levels in cells and tissues. These evolutionary conserved polytopic membrane proteins are present in all phyla from simplest life forms (bacteria) to highly evolved eukaryotes (Homo sapiens). The presumed early function in metal detoxification remains the main function of Copper-ATPases in prokaryotic kingdom. In eukaryotes, in addition to removing excess copper from the cell, Copper-ATPases have another equally important function - to supply copper to copper dependent enzymes within the secretory pathway. This review focuses on the origin and diversification of Copper ATPases in eukaryotic organisms. From a single Copper ATPase in protozoans, a divergence into two functionally distinct ATPases is observed with the evolutionary appearance of chordates. Among the key functional domains of Copper-ATPases, the metal-binding N-terminal domain could be responsible for functional diversification of the copper ATPases during the course of evolution. PMID:23024604

Gupta, Arnab; Lutsenko, Svetlana

2012-01-01

319

Evolution of copper transporting ATPases in eukaryotic organisms.  

PubMed

Copper is an essential nutrient for most life forms, however in excess it can be harmful. The ATP-driven copper pumps (Copper-ATPases) play critical role in living organisms by maintaining appropriate copper levels in cells and tissues. These evolutionary conserved polytopic membrane proteins are present in all phyla from simplest life forms (bacteria) to highly evolved eukaryotes (Homo sapiens). The presumed early function in metal detoxification remains the main function of Copper-ATPases in prokaryotic kingdom. In eukaryotes, in addition to removing excess copper from the cell, Copper-ATPases have another equally important function - to supply copper to copper dependent enzymes within the secretory pathway. This review focuses on the origin and diversification of Copper ATPases in eukaryotic organisms. From a single Copper ATPase in protozoans, a divergence into two functionally distinct ATPases is observed with the evolutionary appearance of chordates. Among the key functional domains of Copper-ATPases, the metal-binding N-terminal domain could be responsible for functional diversification of the copper ATPases during the course of evolution. PMID:23024604

Gupta, Arnab; Lutsenko, Svetlana

2012-04-01

320

Electrodialytic remediation of copper mine tailings.  

PubMed

Mining activities in Chile have generated large amounts of solid waste, which have been deposited in mine tailing impoundments. These impoundments cause concern to the communities due to dam failures or natural leaching to groundwater and rivers. This work shows the laboratory results of nine electrodialytic remediation experiments on copper mine tailings. The results show that electric current could remove copper from watery tailing if the potential gradient was higher than 2 V/cm during 21 days. With addition of sulphuric acid, the process was enhanced because the pH decreased to around 4, and the copper by this reason was released in the solution. Furthermore, with acidic tailing the potential gradient was less than 2 V/cm. The maximum copper removal reached in the anode side was 53% with addition of sulphuric acid in 21 days experiment at 20 V using approximately 1.8 kg mine tailing on dry basis. In addition, experiments with acidic tailing show that the copper removal is proportional with time. PMID:15629576

Hansen, Henrik K; Rojo, Adrián; Ottosen, Lisbeth M

2005-01-31

321

Characterization of copper-resistant rhizosphere bacteria from Avena sativa and Plantago lanceolata for copper bioreduction and biosorption.  

PubMed

Copper is a toxic heavy metal widely used to microbial control especially in agriculture. Consequently, high concentrations of copper residues remain in soils selecting copper-resistant organisms. In vineyards, copper is routinely used for fungi control. This work was undertaken to study copper resistance by rhizosphere microorganisms from two plants (Avena sativa L. and Plantago lanceolata L.) common in vineyard soils. Eleven rhizosphere microorganisms were isolated, and four displayed high resistance to copper. The isolates were identified by 16S rRNA gene sequence analysis as Pseudomonas putida (A1), Stenotrophomonas maltophilia (A2) and Acinetobacter sp. (A6), isolated from Avena sativa rhizosphere, and Acinetobacter sp. (T5), isolated from Plantago lanceolata rhizosphere. The isolates displayed high copper resistance in the temperature range from 25°C to 35°C and pH in the range from 5.0 to 9.0. Pseudomonas putida A1 resisted as much as 1,000 mg L(-1) of copper. The isolates showed similar behavior on copper removal from liquid medium, with a bioremoval rate of 30% at 500 mg L(-1) after 24 h of growth. Speciation of copper revealed high copper biotransformation, reducing Cu(II) to Cu(I), capacity. Results indicate that our isolates are potential agents for copper bioremoval and bacterial stimulation of copper biosorption by Avena sativa and Plantago lanceolata. PMID:22002857

Andreazza, Robson; Okeke, Benedict C; Pieniz, Simone; Camargo, Flávio A O

2012-04-01

322

49 CFR 192.377 - Service lines: Copper.  

Code of Federal Regulations, 2010 CFR

...CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Customer Meters, Service Regulators, and Service Lines § 192.377 Service lines: Copper. Each copper service line installed...

2010-10-01

323

49 CFR 192.377 - Service lines: Copper.  

Code of Federal Regulations, 2011 CFR

...CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Customer Meters, Service Regulators, and Service Lines § 192.377 Service lines: Copper. Each copper service line installed...

2011-10-01

324

49 CFR 192.377 - Service lines: Copper.  

Code of Federal Regulations, 2013 CFR

...CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Customer Meters, Service Regulators, and Service Lines § 192.377 Service lines: Copper. Each copper service line installed...

2013-10-01

325

49 CFR 192.377 - Service lines: Copper.  

Code of Federal Regulations, 2012 CFR

...CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Customer Meters, Service Regulators, and Service Lines § 192.377 Service lines: Copper. Each copper service line installed...

2012-10-01

326

Copper toxicosis in New Zealand White rabbits (Oryctolagus cuniculus).  

PubMed

Six 12- to 14-month-old New Zealand White rabbits were diagnosed with copper toxicosis. These rabbits were part of a group of 110 purchased and shipped overnight for research purposes. On arrival, the group experienced an abrupt diet change. Eight died over 3 weeks and 6 were submitted for postmortem examination. Microscopic findings included severe centrilobular to midzonal hepatocellular necrosis with rhodanine stain-positive copper granules in the remaining hepatocytes. Mild periportal fibrosis and biliary hyperplasia, hemoglobinuric nephrosis, and splenic erythrophagocytosis were also observed. Hepatic copper concentrations were elevated, ranging from 319 to 997 ppm. Clinical disease was not previously observed in younger rabbits gradually transitioned from the supplier's copper-supplemented diet. Copper toxicosis likely occurred in these rabbits from a combination of (1) increased duration of copper supplementation leading to increased hepatocellular stores and (2) stress leading to anorexia and release of hepatocellular copper stores similar to chronic copper toxicosis as described in sheep. PMID:23697481

Ramirez, C J; Kim, D Y; Hanks, B C; Evans, T J

2013-11-01

327

Growth of copper on diatom silica by electroless deposition technique  

NASA Astrophysics Data System (ADS)

In this study, the growth of copper on porous diatom silica by electroless deposition method has been demonstrated for the first time. Raman peaks of copper (145, 213, and 640 cm-1) appeared in the copper-coated, Amphora sp. and Skeletonema sp. diatom samples, confirming the successful deposition of copper. Scanning electron microscopy (SEM) indicated the presence of copper on the diatom silica surface. The 3D intricate structure of diatom was still evident by optical and scanning electron microscopy analyses when the diatom samples were immersed in the copper bath for only 5 hours. Incubating the diatom samples in the copper bath for 24 h produced a dense coating on the diatom surface and covered the intricate 3D structure of the diatom silica. These results present possibilities of the fabrication of hierarchically organized copper with 3D diatom replica structures.

Dalagan, Juliet Q.; Enriquez, Erwin P.; Li, Lain-Jong; Lin, Cheng-Te

2013-04-01

328

MICHIGAN TECHNOLOGICAL UNIVERSITY ARCHIVES COPPER COUNTRY HISTORICAL COLLECTION  

E-print Network

MICHIGAN TECHNOLOGICAL UNIVERSITY ARCHIVES AND COPPER COUNTRY HISTORICAL COLLECTION GENEALOGICAL & Copper Country Historical Collection J. Robert Van Pelt Library Michigan Technological University local high schools and Michigan Technological University, centennial books, and local history titles

329

Effect of copper impurity on polycrystalline silicon solar cells  

NASA Technical Reports Server (NTRS)

The presence of copper impurity, up to 10 to the 15th atoms/cc, in single crystal silicon has been shown to have no deleterious effect on the p-n junction solar cell performance. However, in polycrystalline silicon, copper atoms tend to migrate to the defect sites because of the structural sensitive properties of copper. This study was undertaken to investigate the influence of this behavior of copper impurity on the performance of p-n junction solar cells fabricated from structurally imperfect silicon. Two sets of polycrystalline silicon substrates containing copper were examined. In one set of samples, copper was incorporated during growth, whereas in the other, copper was diffused. Solar cells were fabricated on both the sets of substrates by a standard process. Dark and light I-V and spectral response characteristics of the cells were measured and compared with copper-free polycrystalline silicon solar cells. The results and the model are discussed.

Daud, T.; Koliwad, K. M.

1978-01-01

330

Metals in Metal Salts: A Copper Mirror Demonstration  

ERIC Educational Resources Information Center

A simple lecture demonstration is described to show the latent presence of metal atoms in a metal salt. Copper(II) formate tetrahydrate is heated in a round-bottom flask forming a high-quality copper mirror.

Pike, Robert D.

2010-01-01

331

Pathogenic adaptations to host-derived antibacterial copper  

PubMed Central

Recent findings suggest that both host and pathogen manipulate copper content in infected host niches during infections. In this review, we summarize recent developments that implicate copper resistance as an important determinant of bacterial fitness at the host-pathogen interface. An essential mammalian nutrient, copper cycles between copper (I) (Cu+) in its reduced form and copper (II) (Cu2+) in its oxidized form under physiologic conditions. Cu+ is significantly more bactericidal than Cu2+ due to its ability to freely penetrate bacterial membranes and inactivate intracellular iron-sulfur clusters. Copper ions can also catalyze reactive oxygen species (ROS) generation, which may further contribute to their toxicity. Transporters, chaperones, redox proteins, receptors and transcription factors and even siderophores affect copper accumulation and distribution in both pathogenic microbes and their human hosts. This review will briefly cover evidence for copper as a mammalian antibacterial effector, the possible reasons for this toxicity, and pathogenic resistance mechanisms directed against it. PMID:24551598

Chaturvedi, Kaveri S.; Henderson, Jeffrey P.

2014-01-01

332

New canine models of copper toxicosis: diagnosis, treatment, and genetics.  

PubMed

The One Health principle recognizes that human health, animal health, and environmental health are inextricably linked. An excellent example is the study of naturally occurring copper toxicosis in dogs to help understand human disorders of copper metabolism. Besides the Bedlington terrier, where copper toxicosis is caused by a mutation in the COMMD1 gene, more complex hereditary forms of copper-associated hepatitis were recognized recently in other dog breeds. The Labrador retriever is one such breed, where an interplay between genetic susceptibility and exposure to copper lead to clinical copper toxicosis. Purebred dog populations are ideal for gene mapping studies, and because genes involved in copper metabolism are highly conserved across species, newly identified gene mutations in the dog may help unravel the genetic complexity of different human forms of copper toxicosis. Furthermore, increasing knowledge with respect to diagnosis and treatment strategies will benefit both species. PMID:24758744

Fieten, Hille; Penning, Louis C; Leegwater, Peter A J; Rothuizen, Jan

2014-05-01

333

Coordination geometry around copper in a Schiff-base trinuclear copper complex using EXAFS spectroscopy  

NASA Astrophysics Data System (ADS)

In the present investigation, we have studied extended X-ray absorption fine structure (EXAFS) spectra of a trinuclear Schiff-base copper complex tetraaqua-di-?3-(N-salicylidene-DL-glutamato)-tricopper(II)heptahydrate, [Cu3(C12H10NO5)2 (H2O)4]. 7H2O, in which three metal sites are present. One metal site is square-pyramidal (4+1) and other two similar metal sites are tetragonally distorted octahedral (4+2). EXAFS has been recorded at the K-edge of copper in the complex at the dispersive EXAFS beamline at 2 GeV Indus-2 synchrotron source at RRCAT, Indore, India. The analysis of EXAFS spectra of multinuclear metal complexes pose some problems due to the presence of many absorbing atoms, even when the absorbing atoms may be of the same element. Hence, using the available crystal structure of the complex, theoretical models have been generated for the different copper sites separately, which are then fitted to the experimental EXAFS data. The two coordination geometries around the copper sites have been determined. The contributions of the different copper sites to the experimental spectrum have been estimated. The structural parameters, which include bond-lengths, coordination numbers and thermal disorders, for the two types of copper sites have been reported. Further, copper has been found to be in +2 oxidation state at these metal sites.

Gaur, Abhijeet; Shrivastava, B. D.; Gaur, D. C.; Prasad, J.; Srivastava, K.; Jha, S. N.; Bhattacharyya, D.; Poswal, A.

2012-05-01

334

Thermal resistance across a copper/Kapton/copper interface at cryogenic temperatures  

SciTech Connect

The high-{Tc} superconductor current lead heat intercept connection, which is utilized as a thermal intercept to remove the Joule heat from the upper stage lead to a heat sink operating at 50--77 K, consists of a structure where a 152-{micro}m film is sandwiched between two concentric copper cylinders. The material chosen for the insulating film is Kapton MT, a composite film which has a relatively low thermal resistance, but yet a high voltage standoff capability. Here, the measured thermal conductance of a copper/Kapton MT/copper junction in a flat-plate geometry is compared to the results obtained from the actual heat intercept connection. Increasing the contact pressure reduces the thermal resistance to a minimum value determined by the film conduction resistance. A comparison between the resistance of the copper/Kapton MT/copper junction and a copper/G-10/copper junction demonstrates that the Kapton MT layer yields a lower thermal resistance while still providing adequate electrical isolation.

Zhao, L.; Phelan, P.E. [Arizona State Univ., Tempe, AZ (United States). Dept. of Mechanical and Aerospace Engineering; Niemann, R.C. [Argonne National Lab., IL (United States); Weber, B.R. [Superconductivity, Inc., Madison, WI (United States)

1997-09-01

335

Copper corrosion-simulated uterine solutions.  

PubMed

We studied the copper corrosion and product layers originating in a simulated uterine solution at pH values 6.3 and 8.0 for 15, 65, 180, and 360 days at 37 degrees C. Absorbance measurements were performed. Corrosion product layers on the copper surface were characterized by scanning electron microscopy, energy dispersive x-ray, and x-ray photo-electron spectroscopy techniques. Copper release for pH 6.3 and 8.0 was 3.4-4.5 microg/day for 15 days and 0.1-0.3 microg/day for 360 days. Of the order of 30%-40% of dissolved cupric ions were trapped in the product layers. The main compounds identified were cuprite (Cu(2)O), calcite (CaCO(3)), and phosphates. PMID:10958884

Bastidas, J M; Cano, E; Mora, N

2000-06-01

336

Comparative effects of dissolved copper and copper oxide nanoparticle exposure to the sea anemone, Exaiptasia pallida.  

PubMed

Increasing use of metal oxide nanoparticles (NP) by various industries has resulted in substantial output of these NP into aquatic systems. At elevated concentrations, NP may interact with and potentially affect aquatic organisms. Environmental implications of increased NP use are largely unknown, particularly in marine systems. This research investigated and compared the effects of copper oxide (CuO) NP and dissolved copper, as copper chloride (CuCl2), on the sea anemone, Exaiptasia pallida. Sea anemones were collected over 21 days and tissue copper accumulation and activities of the enzymes: catalase, glutathione peroxidase, glutathione reductase, and carbonic anhydrase were quantified. The size and shape of CuO NP were observed using a ecanning electron microscope (SEM) and the presence of copper was confirmed by using Oxford energy dispersive spectroscopy systems (EDS/EDX). E. pallida accumulated copper in their tissues in a concentration- and time-dependent manner, with the animals exposed to CuCl2 accumulating higher tissue copper burdens than those exposed to CuO NP. As a consequence of increased copper exposure, as CuO NP or CuCl2, anemones increased activities of all of the antioxidant enzymes measured to some degree, and decreased the activity of carbonic anhydrase. Anemones exposed to CuO NP generally had higher anti-oxidant enzyme activities than those exposed to the same concentrations of CuCl2. This study is useful in discerning differences between CuO NP and dissolved copper exposure and the findings have implications for exposure of aquatic organisms to NP in the environment. PMID:25661886

Siddiqui, Samreen; Goddard, Russell H; Bielmyer-Fraser, Gretchen K

2015-03-01

337

Cytotoxic activities of chitosan nanoparticles and copper-loaded nanoparticles  

Microsoft Academic Search

Chitosan nanoparticles and copper(II)-loaded chitosan nanoparticles were prepared based on the ionic gelation of chitosan with tripolyphosphate anions and copper ion sorption. In this study, the cytotoxic activities of the chitosan nanoparticles and copper(II)-loaded chitosan nanoparticles was investigated and a relationship between physiochemical properties and activity is suggested. The chitosan nanoparticles and copper(II)-loaded chitosan nanoparticles elicited dose-dependent inhibitory effects on

Lifeng Qi; Zirong Xu; Xia Jiang; Yan Li; Minqi Wang

2005-01-01

338

Pesticidal Copper (I) Oxide: Environmental Fate and Aquatic Toxicity  

Microsoft Academic Search

\\u000a Besides being a naturally occurring element and an essential micronutrient, copper is used as a pesticide, but at generally\\u000a higher concentrations. Copper, unlike organic pesticides, does not degrade, but rather enters a complex biogeochemical cycle.\\u000a In the water column, copper can exist bound to both organic and inorganic species and as free or hydrated copper ions. Water\\u000a column chemistry affects

Lina Kiaune; Nan Singhasemanon

339

Studies on copper alloys containing chromium on the copper side phase diagram  

NASA Technical Reports Server (NTRS)

Specimens were prepared from vacuum melted alloys of high purity vacuum melted copper and electrolytic chromium. The liquidus and eutectic point were determined by thermal analysis. The eutectic temperature is 1974.8 F and its composition is 1.28 wt% of chromium. The determination of solid solubility of chromium in copper was made by microscopic observation and electrical resistivity measurement. The solubility of chromium in solid copper is 0.6 wt% at 1050 F, 0.4 wt% at 1000 F, 0.25 wt% at 950 F, 0.17 wt% at 900 F, and 0.30 wt% at 840 F.

Doi, T.

1984-01-01

340

Copper Wire Bonding Concerns and Best Practices  

NASA Astrophysics Data System (ADS)

Copper wire bonding of microelectronic parts has developed as a means to cut the costs of using the more mature technology of gold wire bonding. However, with this new technology, changes in the bonding processes as well as bonding metallurgy can affect product reliability. This paper discusses the challenges associated with copper wire bonding and the solutions that the industry has been implementing. The paper also provides information to enable customers to conduct qualification and reliability tests on microelectronic packages to facilitate adoption in their target applications.

Chauhan, Preeti; Zhong, Z. W.; Pecht, Michael

2013-08-01

341

Simultaneous amperometric determination of nickel and copper.  

PubMed

A method is described for the amperometric titration of nickel and successive amperometric determination of copper and nickel. Nickel (1.0-16.0 mg) and copper (1.0-11.0 mg) could be determined with an average error of less than 1%. Cobalt interferes but chloride does not. Interference by aluminium, iron(III) and chromium can be eliminated. Zinc and manganese do not interfere if the correct applied voltage is chosen. The procedures can be utilized in the analysis of alloys such as nichrome, Raney nickel, constantan, german silver and manganin. It is best to use the standard addition method for less than 3 mg of nickel. PMID:18961683

Reddy, Y K; Rao, S B; Raju, N A

1975-06-01

342

Mineral resource of the month: copper  

USGS Publications Warehouse

The article provides information on copper and its various uses. It was the first metal used by humans and is considered as one of the materials that played an important role in the development of civilization. It is a major industrial metal because of its low cost, availability, electrical conductivity, high ductility and thermal conductivity. Copper has long been used in the circuitry of electronics and the distribution of electricity and is now being used in silicon-based computer chips, solar and wind power generation, and coinage.

U.S. Geological Survey

2011-01-01

343

6,000 years of copper smelting : Center for the Study of Copper Smelting in Ancient Societies  

E-print Network

In 1959 professor of archeology Beno Rothenberg began investigating the production of copper in the Sinai desert and Aravah region of southern Israel. He discovered over 650 previously unknown ancient copper mining and ...

Steinberg, Marc J. (Marc Jonathan), 1969-

2000-01-01

344

Tantalum-copper alloy and method for making  

DOEpatents

A tantalum-copper alloy can be made by preparing a consumable electrode consisting of an elongated copper billet containing at least two spaced apart tantalum rods extending longitudinally the length of the billet. The electrode is placed in a dc arc furnace and melted under conditions which co-melt the copper and tantalum to form the alloy.

Schmidt, F.A.; Verhoeven, J.D.; Gibson, E.D.

1983-06-01

345

Speciation and bio-availability of copper in Lake Tjeukemeer  

Microsoft Academic Search

Chapter 1: introductionIn this thesis an account is given of a research project dealing with the chemical speciation and bioavailability of copper in Lake Tjeukemeer, a lake in the north of the Netherlands. The reason for the initiation of this project was a lack of knowledge about the speciation of copper and the influence of copper on the behaviour of

W. Verweij

1991-01-01

346

Pathological Consequences of Copper Deficiency and Cobalt Deficiency  

Microsoft Academic Search

Aspects of the pathology of copper deficiency in several species, and cobalt deficiency in sheep, are summarized. An attempt is made to interpret morphological changes in copper-deficient animals in terms of biochemical defects. The common denominator may be mitochondrial lesions, with a generalized effect on energy-dependent synthetic functions of the cell. In copper deficiency, such defects can be attributed to

B. F. Fell

1981-01-01

347

Electrodialytic remediation of copper mine tailings using bipolar electrodes  

Microsoft Academic Search

In this work an electrodialytic remediation (EDR) cell for copper mine tailings with bipolar stainless steel plates was analyzed. The bipolar plates were inserted inside the tailings, dividing it into independent electrochemical cells or sections, in order to increase the copper removal efficiency from mine tailings. The bipolar plates design was tested on acidic copper mine tailings with a fixed:

Adrián Rojo; Luis Cubillos

2009-01-01

348

LONG-TERM IMPACTS OF ORTHOPHOSPHATE TREATMENT ON COPPER  

EPA Science Inventory

Laboratory, pilot, and field data collected support the theoretical "cupric hydroxide" copper solubility model. For the short time frames inherent in laboratory and pilot studies of copper solubility and in initial field monitoring for the LCR from Tier 1 soldered copper sites, c...

349

IN-HOUSE CORROSION RESEARCH EMPHASIZING LEAD, COPPER AND IRON  

EPA Science Inventory

Lead and copper are directly regulated via the "Lead and Copper Rule;" however, water suppliers must balance all water treatment processes in order to simultaneously comply with all regulations. Specific research needs for copper and lead chemistry still exist, as applications o...

350

Hepatic hyperplasia and cancer in rats: alterations in copper metabolism  

Microsoft Academic Search

We previously demonstrated that rats exposed to the peroxisome proliferator (PP) diethylhexylphthalate (DEHP) had reduced serum ceruloplasmin (CP) oxidase activity, which suggests tissue copper deposition. Copper is highly toxic in excess, and results in cellular damage and hepatocellular carcinomas (HCC). This study addresses changes in expression of copper-related genes and metal accumulation in hyperplastic liver and tumors induced by PP.

Patricia K. Eagon; Annette G. Teepe; Mary S. Elm; Stasa D. Tadic; Marilyn J. Epley; Bonnie E. Beiler; Hisashi Shinozuka; Kalipatnapu N. Rao

351

Moisture induced corrosion in gold and copper ball bonds  

Microsoft Academic Search

High gold prices have led to renewed interest in replacing gold with copper in existing packages and new packages in order to save costs. Although reliability is often cited as a reason for using copper, the main driving force for its use is undoubtedly cost. Perceptions that copper wire is more reliable are based on the notion that the intermetallics

C. D. Breach; Wai Mun Tee; Teck Kheng Lee; R. Holliday

2010-01-01

352

Diffuse emission and control of copper in urban surface runoff  

Microsoft Academic Search

Copper washed off from roofs and roads is considered to be a major contribution to diffuse copper pollution of urban environments. In order to guarantee sustainable protection of soils and water, the long-term strategy is to avoid or replace copper containing materials on roofs and façades. Until achievement of this goal, a special adsorber system is suggested to control the

M. A. Boller; M. Steiner

353

Laser Copper Plasma X-ray Source Debris Characterization  

E-print Network

Laser Copper Plasma X-ray Source Debris Characterization A Thesis Presented by David Hurley 3, 2007 Vice President for Research and Dean of Graduate studies #12;Abstract Laser copper plasma for x-ray lithography. Copper debris in the form of vapor, ions, dust, and high-speed particles

Huston, Dryver R.

354

THE LEAD AND COPPER RULE Anne Sandvig, HDR-EES  

E-print Network

THE LEAD AND COPPER RULE Anne Sandvig, HDR-EES 2008 Historical Background The 1986 Safe Drinking districts and was not mandated. In 1991, the USEPA finalized the Lead and Copper Rule (LCR) in response components and by August 1998 manufacturers were required to comply. The Lead and Copper Rule #12;The USEPA

Maynard, J. Barry

355

COPPER SENSITIVITY OF PACIFIC HERRING, CLUPEA HARENGUS PALLASI,  

E-print Network

COPPER SENSITIVITY OF PACIFIC HERRING, CLUPEA HARENGUS PALLASI, DURING ITS EARLY LIFE HISTORY D. W pallasi, were exposed to copper, using a flow-through bioassay system. Herring embryos were exposed until yolk sac absorption. Embryos were also exposed to 36-h duration pulses of copper in order

356

Heat transfer enhancement of copper nanofluid with acoustic cavitation  

Microsoft Academic Search

Heat transfer characteristics of copper nanofluids with and without acoustic cavitation were investigated experimentally. The effects of such factors as acoustical parameters, nanofluid concentration and fluid subcooling on heat transfer enhancement around a heated horizontal copper tube were discussed in detail. The results indicated that the copper nanoparticles and acoustic cavitation had profound and significant influence on heat transport in

D. W. Zhou

2004-01-01

357

Copper deficiency in a herd of captive muskoxen.  

PubMed Central

At necropsy, a mature muskox cow was found to have exceedingly low serum and liver copper concentrations of 4.8 = mumol/L and 0.02 mmol/kg, respectively. Serum copper levels were also low in remaining members of the herd but returned to normal after parenteral treatment with calcium copper edetate. PMID:9592616

Blakley, B R; Tedesco, S C; Flood, P F

1998-01-01

358

Copper deficiency in a herd of captive muskoxen.  

PubMed

At necropsy, a mature muskox cow was found to have exceedingly low serum and liver copper concentrations of 4.8 = mumol/L and 0.02 mmol/kg, respectively. Serum copper levels were also low in remaining members of the herd but returned to normal after parenteral treatment with calcium copper edetate. PMID:9592616

Blakley, B R; Tedesco, S C; Flood, P F

1998-05-01

359

Metallic copper corrosion rates, moisture content, and growth medium influence survival of copper ion-resistant bacteria  

Microsoft Academic Search

The rapid killing of various bacteria in contact with metallic copper is thought to be influenced by the influx of copper\\u000a ions into the cells, but the exact mechanism is not fully understood. This study showed that the kinetics of contact killing\\u000a of copper surfaces depended greatly on the amount of moisture present, copper content of alloys, type of medium

Jutta Elguindi; Stuart Moffitt; Henrik Hasman; Cassandra Andrade; Srini Raghavan; Christopher Rensing

2011-01-01

360

Formation of copper aluminate spinel and cuprous aluminate delafossite to thermally stabilize simulated copper-laden sludge  

Microsoft Academic Search

The study reported herein indicated the stabilization mechanisms at work when copper-laden sludge is thermally treated with ?-alumina and kaolinite precursors, and evaluated the prolonged leachability of their product phases. Four copper-containing phases – copper oxide (CuO), cuprous oxide (Cu2O), copper aluminate spinel (CuAl2O4), and cuprous aluminate delafossite (CuAlO2) – were found in the thermal reactions of the investigated systems.

Ching-Yao Hu; Kaimin Shih; James O. Leckie

2010-01-01

361

Detoxification mechanism of heavy metals in marine mammals and seabirds: interaction of selenium with mercury, silver, copper, zinc, and cadmium in liver.  

PubMed

Subcellular distribution of mercury, selenium, silver, copper, zinc, and cadmium was determined in the liver of northern fur seals (Callorhinus ursinus), black-footed albatrosses (Diomedea nigripes), and Dall's porpoises (Phocoenoides dalli). Mercury, selenium, and silver were preferentially accumulated in nuclear, lysosomal, and mitochondrial fraction with an increase in their hepatic concentrations, whereas copper, zinc, and cadmium were accumulated mainly in cytosol with an increase in the hepatic concentrations for all three species. To gain insight into the existing state of the metals, they were extracted with four extractants--sodium dodecylsulfate (SDS); 2-mercaptoethanol; 2-mercaptoethanol + guanidinium thiocyanate; and copper sulfate (CuSO4)--at several concentrations from nuclear, lysosomal, and mitochondrial fraction in liver from a specimen of northern fur seal. Extraction efficiencies of the metals for 2-mercaptoethanol + guanidinium thiocyanate and CuSO4 were much higher than those for SDS and 2-mercaptoethanol. Also, for all individuals of the three species, metals were extracted by the three extractants--2% SDS; 0.25 mol/L 2-mercaptoethanol + 5 mol/L guanidinium thiocyanate; and 0.1 mol/L CuSO4--from nuclear, lysosomal, and mitochondrial fraction of liver. In the northern fur seals with higher concentration of mercury, the molar ratio of selenium to mercury approached unity in the nonextractable fraction of 0.25 mol/L 2-mercaptoethanol + 5 mol/L guanidinium thiocyanate, suggesting the possible formation of mercuric selenide (HgSe) with increasing hepatic concentration. Because the nonextractable content of mercury and its distribution were larger for black-footed albatross than those for the other two species, it was suggested that the black-footed albatross has a stronger ability to form a stable compound(s) of mercury in the liver. It is notable that the existing state of silver was similar to that of mercury as judged by their subcellular distribution and the extraction tests, suggesting that silver also interacted with selenium in the liver of marine animals used in this study. PMID:15386135

Ikemoto, T; Kunito, T; Tanaka, H; Baba, N; Miyazaki, N; Tanabe, S

2004-10-01

362

A novel copper=polydimethiylsiloxane nanocomposite for copper-containing intrauterine contraceptive devices  

E-print Network

great efforts on designing the copper=low-density polyethyl- ene (Cu=LDPE) nanocomposite as the new, and the continuous release amount was guaranteed for the novel Cu=LDPE nanocomposites in simulated uterine fluid (SUF

Zheng, Yufeng

363

Ctr6, a vacuolar membrane copper transporter in Schizosaccharomyces pombe.  

PubMed

Aerobic organisms possess efficient systems for the transport of copper. This involves transporters that mediate the passage of copper across biological membranes to reach essential intracellular copper-requiring enzymes. In this report, we identify a new copper transporter in Schizosaccharomyces pombe, encoded by the ctr6(+) gene. The transcription of ctr6(+) is induced under copper-limiting conditions. This regulation is mediated by the cis-acting promoter element CuSE (copper-signaling element) through the copper-sensing transcription factor Cuf1. An S. pombe strain bearing a disrupted ctr6Delta allele displays a strong reduction of copper,zinc superoxide dismutase activity. When the ctr6+ gene is overexpressed from the thiamine-inducible nmt1(+) promoter, the cells are unable to grow on medium containing exogenous copper. Surprisingly, this copper-sensitive growth phenotype is not due to an increase of copper uptake at the cell surface. Instead, copper delivery across the plasma membrane is reduced. Consistently, this results in repressing ctr4(+) gene expression. By using a functional ctr6(+) epitope-tagged allele expressed under the control of its own promoter, we localize the Ctr6 protein on the membrane of vacuoles. Furthermore, we demonstrate that Ctr6 is an integral membrane protein that can trimerize. Moreover, we show that Ctr6 harbors a putative copper-binding Met-X-His-Cys-X-Met-X-Met motif in the amino terminus, which is essential for its function. Our findings suggest that under conditions in which copper is scarce, Ctr6 is required as a means to mobilize stored copper from the vacuole to the cytosol. PMID:12244050

Bellemare, Daniel R; Shaner, Lance; Morano, Kevin A; Beaudoin, Jude; Langlois, Rejean; Labbe, Simon

2002-11-29

364

Cyanobacterial metallochaperone inhibits deleterious side reactions of copper  

PubMed Central

Copper metallochaperones supply copper to cupro-proteins through copper-mediated protein-protein-interactions and it has been hypothesized that metallochaperones thereby inhibit copper from causing damage en route. Evidence is presented in support of this latter role for cyanobacterial metallochaperone, Atx1. In cyanobacteria Atx1 contributes towards the supply of copper to plastocyanin inside thylakoids but it is shown here that in copper-replete medium, copper can reach plastocyanin without Atx1. Unlike metallochaperone-independent copper-supply to superoxide dismutase in eukaryotes, glutathione is not essential for Atx1-independent supply to plastocyanin: Double mutants missing atx1 and gshB (encoding glutathione synthetase) accumulate the same number of atoms of copper per cell in the plastocyanin pool as wild type. Critically, ?atx1?gshB are hypersensitive to elevated copper relative to wild type cells and also relative to ?gshB single mutants with evidence that hypersensitivity arises due to the mislocation of copper to sites for other metals including iron and zinc. The zinc site on the amino-terminal domain (ZiaAN) of the P1-type zinc-transporting ATPase is especially similar to the copper site of the Atx1 target PacSN, and ZiaAN will bind Cu(I) more tightly than zinc. An NMR model of a substituted-ZiaAN-Cu(I)-Atx1 heterodimer has been generated making it possible to visualize a juxtaposition of residues surrounding the ZiaAN zinc site, including Asp18, which normally repulse Atx1. Equivalent repulsion between bacterial copper metallochaperones and the amino-terminal regions of P1-type ATPases for metals other than Cu(I) is conserved, again consistent with a role for copper metallochaperones to withhold copper from binding sites for other metals. PMID:22198771

Tottey, Steve; Patterson, Carl J.; Banci, Lucia; Bertini, Ivano; Felli, Isabella C.; Pavelkova, Anna; Dainty, Samantha J.; Pernil, Rafael; Waldron, Kevin J.; Foster, Andrew W.; Robinson, Nigel J.

2012-01-01

365

Pesticidal copper (I) oxide: environmental fate and aquatic toxicity.  

PubMed

Besides being a naturally occurring element and an essential micronutrient, copper is used as a pesticide, but at generally higher concentrations. Copper, unlike organic pesticides, does not degrade, but rather enters a complex biogeochemical cycle. In the water column, copper can exist bound to both organic and inorganic species and as free or hydrated copper ions. Water column chemistry affects copper speciation and bioavailability. In all water types (saltwater, brackish water, and freshwater), organic ligands in the water column can sequester the majority of dissolved copper, and therefore, organic ligands play the largest role in copper bioavailability. In freshwater, however, the geochemistry of a particular location, including water column characteristics such as water hardness and pH, is a significant factor that can increase copper bioavailability and toxicity. In most cases, organic ligand concentrations greatly exceed copper ion concentrations in the water column and therefore provide a large buffering capacity. Hence, copper bioavailability can be grossly overestimated if it is based on total dissolved copper (TDCu) concentrations alone. Other factors that influence copper concentrations include location in the water column, season, temperature, depth, and level of dissolved oxygen. For example, concentrations of bioavailable copper may be significantly higher in the bottom waters and sediment pore waters, where organic ligands degrade much faster and dissolved copper is constantly resuspended and recycled into the aquatic system. Aquatic species differ greatly in their sensitivity to copper. Some animals, like mollusks, can tolerate high concentrations of the metal, while others are adversely affected by very low concentrations of copper. Emerging evidence shows that very low, sublethal copper levels can adversely affect the sense of smell and behavior of fish. The developmental stage of the fish at the time of copper exposure is critical to the reversibility of sensory function effects. The fish olfactory system may be the most sensitive structure to copper pollution. The major factors that influence copper-induced toxicity are dissolved organic carbon and water salinity. Dissolved organic carbon reduces copper toxicity by sequestering bioavailable copper and forming organic complexes with it. Salinity, on the other hand, influences copper bioavailability at the biological action site and also affects metal biodistribution and bioaccumulation in the organism. Therefore, the salinity gradient can increase or decrease copper toxicity in different aquatic species. In some killifish, copper may affect different organs at different times, depending on the water salinity. The most studied and best explained copper toxicity mechanisms involve inhibition of key enzymes and disruption of osmoregulation in the gill. Other toxicity mechanisms may involve reactive oxygen species generation and changes of gene transcription in the fish olfactory signaling pathway. More studies are needed to evaluate the potential magnitude of copper remobilization from the sediment that may result from climate change and its effects on surface waters. Moreover, the environmental exposure, fate, and ecotoxicity of emerging metal nanoparticles, including nanocopper, will require additional studies as new forms of copper appear from application of nanotechnology to copper compounds. PMID:21541846

Kiaune, Lina; Singhasemanon, Nan

2011-01-01

366

Selective leaching process for the recovery of copper and zinc oxide from copper-containing dust.  

PubMed

The purpose of this study was to develop a resource recovery procedure for recovering copper and zinc from dust produced by copper smelting furnaces during the manufacturing of copper-alloy wires. The concentrations of copper in copper-containing dust do not meet the regulation standards defined by the Taiwan Environmental Protection Administration; therefore, such waste is classified as hazardous. In this study, the percentages of zinc and copper in the dust samples were approximately 38.4% and 2.6%, respectively. To reduce environmental damage and recover metal resources for industrial reuse, acid leaching was used to recover metals from these inorganic wastes. In the first stage, 2 N of sulphuric acid was used to leach the dust, with pH values controlled at 2.0-3.0, and a solid-to-liquid ratio of 1:10. The results indicated that zinc extraction efficiency was higher than 95%. A selective acid leaching process was then used to recover the copper content of the residue after filtration. In the second stage, an additional 1 N of sulphuric acid was added to the suspension in the selective leaching process, and the pH value was controlled at 1.5-2.0. The reagent sodium hydroxide (2 N) was used as leachate at a pH greater than 7. A zinc hydroxide compound formed during the process and was recovered after drying. The yields for zinc and copper were 86.9-93.5% and 97.0-98.9%, respectively. PMID:25191877

Wu, Jun-Yi; Chang, Fang-Chih; Wang, H Paul; Tsai, Ming-Jer; Ko, Chun-Han; Chen, Chih-Cheng

2014-09-26

367

Induction of ceruloplasmin synthesis by interleukin-1 in copper deficient and copper sufficient rats  

SciTech Connect

Ceruloplasmin (Cp) is a copper-containing plasma protein important in the body's acute phase defense system. In copper sufficient rats given two injections of interleukin-1 (IL-1) at 0 and 8 h, ceruloplasmin activity began to significantly increase within 6 h, but did not peak until at least 24 h. The 24 h stimulated activity was 84 +/- 2 umole p-phenylene diamine (pPD) oxidized x min/sup -1/ x L/sup -1/ compared to a control of 43 +/- 5. These rats were injected with 100uCi /sup 3/H-leucine (ip) 2 h before sacrifice to label newly synthesized proteins. When the /sup 3/H immunoprecipitated by rabbit anti-rat Cp serum is expressed as a percent of the /sup 3/H precipitated by trichloroacetic acid (TCA), the basal Cp synthesis rate was 3% of the total serum protein synthesis. The rate of Cp synthesis peaked 12 h after IL-1 injection at 7% of total serum protein synthesis and by 24 h was back to the basal rate. In copper deficient rats, IL-1 given with copper induced pPD oxidase activity, while IL-1 given alone did not stimulate activity. The basal Cp synthesis rate in these rats was 3%, the same as in the copper sufficient rats. In copper deficient rats, the Cp synthesis rate was induced by IL-1 with or without an injection of copper. Therefore, if dietary copper is in short supply, then although Cp synthesis is induced by this mediator of host defense mechanisms, Cp cannot carry out its functions.

Barber, E.F.; Cousins, R.J.

1986-03-01

368

Exploration Into Copper Catalyzed and Copper-less Click Reactions with Re(CO)3 Complexes  

E-print Network

Alumina 50% 3 min NCS Isoxazole Trace 3 Alumina 50% 3 min Copper/ Acetate Triazole 90% yield by HPLC 4 8 1:1 H2O:t- BuOH - 24 hours Copper/ Acetate Isoxazole Success! (New 2) Representative HPLC Trace catalyzed triazole formation A B C Combined HPLC traces of 1, 2, and 3. ~ 7.58, 9.05, and 8.94, respectively

Collins, Gary S.

369

Binding of Copper(I) by the Wilson Disease Protein and Its Copper Chaperone  

Microsoft Academic Search

The Wilson disease protein (WND) is a transport ATPase involved in copper delivery to the secretory pathway. Mutations in WND and its homolog, the Men- kes protein, lead to genetic disorders of copper metab- olism. The WND and Menkes proteins are distinguished from other P-type ATPases by the presence of six soluble N-terminal metal-binding domains containing a con- served CXXC

Amy K. Wernimont; Liliya A. Yatsunyk; Amy C. Rosenzweig

2004-01-01

370

Laser micro welding of copper and aluminum  

NASA Astrophysics Data System (ADS)

Aluminum combines comparably good thermal and electrical properties with a low price and a low material weight. These properties make aluminum a promising alternative to copper for a large number of electronic applications, especially when manufacturing high volume components. However, a main obstacle for a wide use of this material is the lack of a reliable joining process for the interconnection of copper and aluminum. The reasons for this are a large misalignment in the physical properties and even more a poor metallurgical affinity of both materials that cause high crack sensitivity and the formation of brittle intermetallic phases during fusion welding. This paper presents investigations on laser micro welding of copper and aluminum with the objective to eliminate brittle intermetallic phases in the welding structure. For these purposes a combination of spot welding, a proper beam offset and special filler material are applied. The effect of silver, nickel and tin filler materials in the form of thin foils and coatings in a thickness range 3-100 ?m has been investigated. Use of silver and tin filler materials yields to a considerable improvement of the static and dynamic mechanical stability of welded joints. The analysis of the weld microstructure shows that an application even of small amounts of suitable filler materials helps to avoid critical, very brittle intermetallic phases on the interface between copper and solidified melt in the welded joints.

Mys, Ihor; Schmidt, Michael

2006-02-01

371

Alternative Anode Reaction for Copper Electrowinning  

SciTech Connect

This report describes a project funded by the Department of Energy, with additional funding from Bechtel National, to develop a copper electrowinning process with lower costs and lower emissions than the current process. This new process also includes more energy efficient production by using catalytic-surfaced anodes and a different electrochemical couple in the electrolyte, providing an alternative oxidation reaction that requires up to 50% less energy than is currently required to electrowin the same quantity of copper. This alternative anode reaction, which oxidizes ferric ions to ferrous, with subsequent reduction back to ferric using sulfur dioxide, was demonstrated to be technically and operationally feasible. However, pure sulfur dioxide was determined to be prohibitively expensive and use of a sulfur burner, producing 12% SO{sub 2}, was deemed a viable alternative. This alternate, sulfur-burning process requires a sulfur burner, waste heat boiler, quench tower, and reaction towers. The electrolyte containing absorbed SO{sub 2} passes through activated carbon to regenerate the ferrous ion. Because this reaction produces sulfuric acid, excess acid removal by ion exchange is necessary and produces a low concentration acid suitable for leaching oxide copper minerals. If sulfide minerals are to be leached or the acid unneeded on site, hydrogen was demonstrated to be a potential reductant. Preliminary economics indicate that the process would only be viable if significant credits could be realized for electrical power produced by the sulfur burner and for acid if used for leaching of oxidized copper minerals on site.

Not Available

2005-07-01

372

A Simulator for Copper Ore Leaching  

SciTech Connect

This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Copper is a strategic metal and the nation needs a secure supply both for industrial use and military needs. However, demand is growing worldwide and is outstripping the ability of the mining industry to keep up. Improved recovery methods are critically needed to maintain the balance of supply and demand. The goal of any process design should be to increase the amount of copper recovered, control movement of acid and other environmentally harmful chemicals, and reduce energy requirements. To achieve these ends, several improvements in current technology are required, the most important of which is a better understanding of, and the ability to quantify, how fluids move through heterogeneous materials in a complex chemical environment. The goal of this project is create a new modeling capability that couples hydrology with copper leaching chemistry . once the model has been verified and validated, we can apply the model to specific problems associated with heap leaching (flow channeling due to non-uniformities in heap structure, precipitation/dissolution reactions, and bacterial action), to understand the causes of inefficiencies, and to design better recovery systems. We also intend to work with representatives of the copper mining industry to write a coordinated plan for further model development and application that will provide economic benefits to the industry and the nation.

Travis, B.

1999-05-14

373

Method for copper staining of germanium crystals  

NASA Technical Reports Server (NTRS)

Proper conditions for copper staining of germanium crystals include a low solution temperature of 3 degrees C, illumination of the sample by infrared light, and careful positioning of the light source relative to the sample so as to minimize absorption of the infrared light.

Rivet, E. J.

1969-01-01

374

Placenta Copper Transport Proteins in Preeclampsia  

Technology Transfer Automated Retrieval System (TEKTRAN)

Placental insufficiency underlying preeclampsia (PE) is associated with impaired placental angiogenesis. As copper (Cu) is essential to angiogenesis, we investigated differences in the expression of placental Cu transporters Menkes (ATP7A), Wilsons (ATP7B) and the Cu chaperone (CCS) for superoxide d...

375

[Copper deficiency anemia morphologically mimicking myelodysplastic syndrome].  

PubMed

A 64-year-old man underwent kidney transplantation for progressive chronic renal failure which had developed 8 years after allogeneic bone marrow transplantation for acute myeloid leukemia. Because of post-operative complications, he had been placed on intravenous hyperalimentation. Three months after the transplantation, anemia rapidly progressed (hemoglobin, 7.9 g/dl). The proportion of reticulocytes was 0.2%, but white blood cell and platelet counts remained within normal ranges. Serum iron, vitamin B12, and folate levels were normal. Bone marrow examination showed the presence of ringed sideroblasts and cytoplasmic vacuoles in a fraction of erythroid cells. Megakaryocytes were adequate in number with normal morphology. Although the findings were consistent with refractory anemia with ringed sideroblasts according to the WHO classification, cytoplasmic vacuolations were also observed in myeloid cells, suggesting copper deficiency. Indeed, serum copper and ceruloplasmin levels were found to be low (33 ?g/dl and 11 mg/dl, respectively), and oral copper supplementation at a daily dose of 1 mg was initiated. There was a prompt increase in reticulocytes, and the hemoglobin level was normalized within one month, in response to this regimen. In progressive anemia cases with ringed sideroblasts in the bone marrow, copper deficiency should be considered in the differential diagnosis. PMID:24681939

Kikuchi, Taku; Mori, Takehiko; Shimizu, Takayuki; Morita, Shinya; Kono, Hidaka; Nakagawa, Ken; Mitsuhasi, Takayuki; Murata, Mitsuru; Okamoto, Shinichiro

2014-03-01

376

AMBIENT WATER QUALITY CRITERIA FOR COPPER  

EPA Science Inventory

The BLM accounts for the effect of water chemistry (e.g., DOC, pH, alkalinity), in addition to hardness, on metal bioavailability and toxicity while also considering competitive interactions that influence binding of copper at the site of toxicity, or the "biotic ligand". The mo...

377

Uptake and Translocation of Copper in Brassicaceae  

Microsoft Academic Search

Ten cvs. of four Brassicaceae species were tested to evaluate their copper (Cu) uptake and translocation. Germination and root length tests indicated that Brassica juncea cv. Aurea and Raphanus sativus cvs. Rimbo and Saxa were the species with the highest germinability and longest roots at Cu concentrations ranging from 25 up to 200 µM. Raphanus sativus cv. Rimbo grown in hydroponic

Mike F. Quartacci; Elena Cosi; Sandra Meneguzzo; Cristina Sgherri

2003-01-01

378

A Mathematical model of copper corrosion  

E-print Network

A new partial differential model for monitoring and detecting copper corrosion products (mainly brochantite and cuprite) is proposed to provide predictive tools suitable for describing the evolution of damage induced on bronze specimens by sulfur dioxide (SO_2) pollution. This model is characterized by the movement of a double free boundary. Numerical simulations show a nice agreement with experimental result.

Clarelli, Fabrizio; Natalini, Roberto

2012-01-01

379

Electronic Properties of Rocksalt Copper Monoxide  

NASA Astrophysics Data System (ADS)

Rocksalt copper monoxide, although not yet synthetically realized in bulk form, can be studied computationally as a proxy for the family of layered HTSC copper oxides. We report results for a series of tetragonal CuO rocksalt structures with c/a lattice parameter ratios ranging from 1.0 to 1.5, employing the plane-wave pseudopotential method with exchange/correlation LDA+U. As expected, we obtain a metallic state for U = 0 at all values of c/a given that the nominal valence electron configuration for Cu in copper monoxides is 3d^9 yielding a partially occupied conduction band. However, completely unexpected was our finding similar metallic properties in rocksalt CuO for all physically plausible values of U (up to 10 eV) and c/a between 1.0 to approximately 1.2. Only for c/a > 1.2 do our calculations reveal the opening of a Mott-Hubbard charge-transfer gap. We interpret our results^1 as supporting the original motivations of Bednorz and Mueller that high temperature superconductivity in the layered copper oxide perovskites may begin with their tendency to exhibit Jahn-Teller strong electron-phonon coupling^2. ^1P. M. Grant, J. Phys: CS 129 (2008) 01242. ^2J. G. Bednorz and K. A. Mueller, Rev. Mod. Phys. 60 (1988) 585.

Grant, Paul Michael

2009-03-01

380

Hydrogen isotope retention and release from copper  

Microsoft Academic Search

The Tokamak Fusion Test Reactor (TFTR) at the Princeton Plasma Physics Laboratory is considering the use of tritium neutral beams during the deuterium--tritium phase of operation in 1990. A concern is the tritium inventory that will develop in neutral beam components such as the copper calorimeter. In this paper we report on measurements and calculations of hydrogen isotope retention and

K. L. Wilson; R. A. Causey; M. I. Baskes; J. Kamperschroer

1987-01-01

381

COPPER PITTING CORROSION: A CASE STUDY  

EPA Science Inventory

Localized or pitting corrosion of copper pipes used in household drinking-water plumbing is a problem for many water utilities and their customers. Extreme attack can lead to pinhole water leaks that may result in water damage, mold growth, and costly repairs. Water quality has b...

382

Antistatic Polycarbonate/Copper Oxide Composite  

NASA Technical Reports Server (NTRS)

A composite material consisting of polycarbonate filled with copper oxide has been found to be suitable as an antistatic material. This material was developed to satisfy a requirement for an antistatic material that has a mass density less than that of aluminum and that exhibits an acceptably low level of outgassing in a vacuum.

Kovich, Michael; Rowland, George R., Jr.

2003-01-01

383

Minnows get columnaris too; copper sulfate works!  

Technology Transfer Automated Retrieval System (TEKTRAN)

A study was conducted to compare the therapeutic effects of copper sulfate (CuSO4), when delivered in either a flow-through or static system, on the survival of golden shiner (Notemigonus crysoleucas; Fig. 1A) and fathead minnow (Pimephales promelas; Fig. 1B) infected with Flavobacterium columnare (...

384

Cold pressure welded copper-constantan thermocouples  

Microsoft Academic Search

Cold pressure welding has been used to produce a lap junction between 0.15 mm thick strips of copper and constantan which had been plated with 2 mu m of nickel. The junction thickness after welding was 0.10 mm, and after further cold rolling to 0.06 mm a thermocouple performance within the requirements of BS 1041 (1966) was obtained.

R. Vipond

1975-01-01

385

Copper-Triggered Aggregation of Ubiquitin  

Microsoft Academic Search

Neurodegenerative disorders share common features comprising aggregation of misfolded proteins, failure of the ubiquitin- proteasome system, and increased levels of metal ions in the brain. Protein aggregates within affected cells often contain ubiquitin, however no report has focused on the aggregation propensity of this protein. Recently it was shown that copper, differently from zinc, nickel, aluminum, or cadmium, compromises ubiquitin

Fabio Arnesano; Simone Scintilla; Elena Bonfrate; Chiara Ingrosso; Maurizio Losacco; Teresa Pellegrino; Enrico Rizzarelli; Giovanni Natile

2009-01-01

386

Copper-Catalyzed Oxytrifluoromethylation of Unactivated Alkenes  

PubMed Central

A mild, versatile and convenient method for the efficient oxytrifluoromethylation of unactivated alkenes has been developed based on a copper-catalyzed oxidative difunctionalization strategy. This methodology provides access to a variety of classes of synthetically useful CF3-containing building blocks from simple starting materials. PMID:22804336

Zhu, Rong; Buchwald, Stephen L.

2012-01-01

387

THE CHEMISTRY OF NEW COPPER PLUMBING  

EPA Science Inventory

The presence of sulfate, bicarbonate and orthophosphate can change the type of solid present in systems containing cupric ion or cupric hydroxide solids. In some cases, a short term reduction in copper solubility is realized, but over longer periods of time formation of basic cup...

388

Fabrication of superhydrophobic copper surface with excellent corrosion resistance  

NASA Astrophysics Data System (ADS)

This article presents an effective and facile method for preparing the superhydrophobic copper surface with excellent corrosion resistance. The superhydrophobic copper surfaces were fabricated by oxidizing, heat-treating, and alkyl chains' grafting. The resulting copper plates take on the binary structure which is composed of a great deal of nanosheets and needle-like/rod-like fibers. Just grounded on both the micro- and nanoscale hierarchical surface and the grafted long alkyl chains, the resulting copper plates are endued with the excellent water repellence, while the water contact angle and sliding angle can reach 157.3° and 5°, respectively. As a result, the superhydrophobic copper plates get the outstanding corrosion resistance.

Feng, Libang; Zhao, Libin; Qiang, Xiaohu; Liu, Yanhua; Sun, Zhiqiang; Wang, Bei

2014-12-01

389

Copper hazards to fish, wildlife and invertebrates: a synoptic review  

USGS Publications Warehouse

Selective review and synthesis of the technical literature on copper and copper salts in the environment and their effects primarily on fishes, birds, mammals, terrestrial and aquatic invertebrates, and other natural resources. The subtopics include copper sources and uses; chemical and biochemical properties; concentrations of copper in field collections of abiotic materials and living organisms; effects of copper deficiency; lethal and sublethal effects on terrestrial plants and invertebrates, aquatic organisms, birds and mammals, including effects on survival, growth, reproduction, behavior, metabolism, carcinogenicity, matagenicity, and teratogenicity; proposed criteria for the protection of human health and sensitive natural resources; and recommendations for additional research.

Eisler, Ronald

1998-01-01

390

Synthesis of carbon nanotubes and nanotube forests on copper catalyst  

NASA Astrophysics Data System (ADS)

The growth of carbon nanotubes on bulk copper is studied. We show for the first time, that super growth chemical vapor deposition method can be successfully applied for preparation of nanotubes on copper catalyst, and the presence of hydrogen is necessary. Next, different methods of copper surface activation are studied, to improve catalyst efficiency. Among them, applied for the first time for copper catalyst in nanotubes synthesis, sulfuric acid activation is the most promising. Among tested samples the surface modified for 10 min is the most active, causing the growth of vertically aligned carbon nanotube forests. Obtained results have potential importance in application of nanotubes and copper in electronic chips and nanodevices.

Kruszka, Bartosz; Terzyk, Artur P.; Wi?niewski, Marek; Gauden, Piotr A.; Szybowicz, Miros?aw

2014-09-01

391

Hydrophobic fluoroalkylsilane nanolayers for inhibiting copper diffusion into silica  

NASA Astrophysics Data System (ADS)

Molecular nanolayers (MNLs) are attractive for suppressing chemical transport and mixing at copper-silica interfaces. Here, we demonstrate that hydrophobic fluoroalkyl moieties enhance the effectiveness of organosilane MNLs to inhibit copper diffusion. Bias thermal annealing of copper-MNL-silica capacitors with MNLs having different fluoroalkyl contents, combined with electron spectroscopy and contact angle measurements, show that the enhanced barrier properties are due to diminished water uptake and curtailed copper ionization. Our results suggest that controlling interface moisture content using hydrophobic moieties can complement copper ion immobilization by hydrophilic groups in MNL barriers.

Garg, Saurabh; Singh, Binay; Teki, Ranganath; Lane, Michael W.; Ramanath, Ganpati

2010-04-01

392

Conserved residue modulates copper-binding properties through structural dynamics in human copper chaperone Atox1.  

PubMed

The human copper chaperone Atox1 plays a central role in the transport of copper in cells. It has been reported that the conserved residue Lys60 contributes to the heterocomplex stability of Atox1 with its target protein ATPase, and that the K60A mutation could diminish the copper transfer. In this work, we carried out the structure determination and dynamic analysis of Atox1 with the K60A mutation in order to elucidate the role of the conserved residue Lys60 in the copper transport. Results show that the K60A mutation results in crucial secondary structure rearrangements and side-chain orientation alteration of the metal-binding residues in Atox1. Protein dynamic studies reveal that the K60A mutation leads to increased overall flexibility, and a significant difference in dynamic properties of the metal-binding sites. The structure and dynamic changes cause a decrease in the copper-binding stability of the K60A mutant. In addition, Cu(i)-mediated hetero-protein interactions with ATP7A are present in the metal transfer of both Atox1 variants, although copper transfer is accompanied with smaller structural alteration in the K60A mutant. These results indicate that Lys60 is crucial in maintaining the structure and dynamic properties of Atox1. PMID:24056613

Xi, Zhaoyong; Shi, Chaowei; Tian, Changlin; Liu, Yangzhong

2013-11-01

393

Modeling MIC copper release from drinking water pipes.  

PubMed

Copper is used for household drinking water distribution systems given its physical and chemical properties that make it resistant to corrosion. However, there is evidence that, under certain conditions, it can corrode and release unsafe concentrations of copper to the water. Research on drinking water copper pipes has developed conceptual models that include several physical-chemical mechanisms. Nevertheless, there is still a necessity for the development of mathematical models of this phenomenon, which consider the interaction among physical-chemical processes at different spatial scales. We developed a conceptual and a mathematical model that reproduces the main processes in copper release from copper pipes subject to stagnation and flow cycles, and corrosion is associated with biofilm growth on the surface of the pipes. We discuss the influence of the reactive surface and the copper release curves observed. The modeling and experimental observations indicated that after 10h stagnation, the main concentration of copper is located close to the surface of the pipe. This copper is associated with the reactive surface, which acts as a reservoir of labile copper. Thus, for pipes with the presence of biofilm the complexation of copper with the biomass and the hydrodynamics are the main mechanisms for copper release. PMID:24398414

Pizarro, Gonzalo E; Vargas, Ignacio T; Pastén, Pablo A; Calle, Gustavo R

2014-06-01

394

Intracytoplasmic Copper Homeostasis Controls Cytochrome c Oxidase Production  

PubMed Central

ABSTRACT Copper is an essential micronutrient used as a metal cofactor by a variety of enzymes, including cytochrome c oxidase (Cox). In all organisms from bacteria to humans, cellular availability and insertion of copper into target proteins are tightly controlled due to its toxicity. The major subunit of Cox contains a copper atom that is required for its catalytic activity. Previously, we identified CcoA (a member of major facilitator superfamily transporters) as a component required for cbb3-type Cox production in the Gram-negative, facultative phototroph Rhodobacter capsulatus. Here, first we demonstrate that CcoA is a cytoplasmic copper importer. Second, we show that bypass suppressors of a ccoA deletion mutant suppress cbb3-Cox deficiency by increasing cellular copper content and sensitivity. Third, we establish that these suppressors are single-base-pair insertion/deletions located in copA, encoding the major P1B-type ATP-dependent copper exporter (CopA) responsible for copper detoxification. A copA deletion alone has no effect on cbb3-Cox biogenesis in an otherwise wild-type background, even though it rescues the cbb3-Cox defect in the absence of CcoA and renders cells sensitive to copper. We conclude that a hitherto unknown functional interplay between the copper importer CcoA and the copper exporter CopA controls intracellular copper homeostasis required for cbb3-Cox production in bacteria like R. capsulatus. PMID:24425735

Ekici, Seda; Turkarslan, Serdar; Pawlik, Grzegorz; Dancis, Andrew; Baliga, Nitin S.; Koch, Hans-Georg; Daldal, Fevzi

2014-01-01

395

Copper Sulfide Precipitation by Yeasts from Acid Mine-Waters  

PubMed Central

Two strains of Rhodotorula and one of Trichosporon precipitated dissolved copper with H2S formed by reducing elemental sulfur with glucose. Iron stimulated this activity under certain conditions. In the case of Rhodotorula strain L, iron stimulated copper precipitation aerobically at a copper concentration of 18 but not 180 ?g/ml. Anaerobically, the L strain required iron for precipitation of copper from a medium with 180 ?g of copper per ml. Rhodotorula strain L was able to precipitate about five times as much copper anaerobically as aerobically. The precipitated copper was identified as copper sulfide, but its exact composition could not be ascertained. Iron was not precipitated by the H2S formed by any of the yeasts. Added as ferric iron, it was able to redissolve copper sulfide formed aerobically by Rhodotorula strain L from 18 but not 180 ?g of copper per ml of medium. Since the yeasts were derived from acid mine-waters, their ability to precipitate copper may be of geomicrobial importance. PMID:16349711

Ehrlich, H. L.; Fox, Sally I.

1967-01-01

396

Adsorption of 2-mercaptobenzothiazole on copper surface from phosphate solutions  

NASA Astrophysics Data System (ADS)

Analysis of the electrochemical and XPS results has shown that adsorption of 2-mercaptobenzothiazole (MBT) on copper electrodes in neutral phosphate solutions proceeds through the formation of the chemical bonds by copper (I) cations with exo-sulfur and nitrogen atoms. A protection layer formed of Cu(I)MBT complex prevents precipitation of copper (II) phosphate on a copper surface. The thickness of the surface film consisting of a complex [Cu(I)MBT]n (having probably polymeric nature), where MBT acts as at least three-dentate ligand, increases depending on the exposure time, reaching 8-9 nm after immersing for 12 h in test solution. Even in a case of the preliminary formation of copper (II) phosphate on the copper electrode at the anodic potential addition of small amounts of MBT results in complete removal of copper (II) phosphate from the surface.

Kazansky, L. P.; Selyaninov, I. A.; Kuznetsov, Yu. I.

2012-07-01

397

Impurity control and removal in copper tankhouse operations  

NASA Astrophysics Data System (ADS)

During copper smelting, most of the undesirable impurities such as Pb, Sb, Bi, and As are only partially removed by oxidation. When white metal and blister copper are in equilibrium, these impurities are distributed mainly into the copper phase, from which their removal is difficult. When copper dissolves during electrorefining in a copper tankhouse, these impurities are continuously released from the anodes either as insoluble phases (slimes), which fall to the bottom of the cell, or as dissolved species in the electrolyte, the transfer of which to the cathode must be inhibited. This article presents impurity control methods in copper tankhouse operations with traditional and newly developed processes. It also summarizes the technologies demonstrated for removal of impurities from electrolyte that prevent them from being recycled in the copper smelting and refining circuit.

Wang, Shijie

2004-07-01

398

Physical, chemical and antimicrobial characterization of copper-bearing material  

NASA Astrophysics Data System (ADS)

Arsenic, cadmium, copper, mercury, silver, and zinc are elements with strong antimicrobial properties. Among them, copper is more environmentally friendly and has both good antibacterial and antifungal properties. It has been shown that copper can even be effective against new viruses such as avian influenza (H5N1). Development of copper-bearing materials for various applications, therefore, is receiving increased attention. The Keweenaw Peninsula of Michigan was the largest native copper mining regions of North America at the turn of the 20th century. Copper was extracted by mining the copper-rich basaltic rock, and steamdriven stamp mills were used to process a great volume of low-grade ores, resulting in huge amounts of crushed waste ore called stamp sands. Approximately 500 million tons of stamp sand were discarded. This material is investigated in this study as an example for the development of antimicrobial materials.

Li, Bowen; Hwang, Jiann-Yang; Drelich, Jaroslaw; Popko, Domenic; Bagley, Susan

2010-12-01

399

Diabetic cardiomyopathy is associated with defective myocellular copper regulation and both defects are rectified by divalent copper chelation  

PubMed Central

Background Heart disease is the leading cause of death in diabetic patients, and defective copper metabolism may play important roles in the pathogenesis of diabetic cardiomyopathy (DCM). The present study sought to determine how myocardial copper status and key copper-proteins might become impaired by diabetes, and how they respond to treatment with the Cu (II)-selective chelator triethylenetetramine (TETA) in DCM. Methods Experiments were performed in Wistar rats with streptozotocin (STZ)-induced diabetes with or without TETA treatment. Cardiac function was analyzed in isolated-perfused working hearts, and myocardial total copper content measured by particle-induced x-ray emission spectroscopy (PIXE) coupled with Rutherford backscattering spectrometry (RBS). Quantitative expression (mRNA and protein) and/or activity of key proteins that mediate LV-tissue-copper binding and transport, were analyzed by combined RT-qPCR, western blotting, immunofluorescence microscopy, and enzyme activity assays. Statistical analysis was performed using Student’s t-tests or ANOVA and p-values of?copper levels and function were severely depressed in rats following 16-weeks’ diabetes, but both were unexpectedly normalized 8-weeks after treatment with TETA was instituted. Localized myocardial copper deficiency was accompanied by decreased expression and increased polymerization of the copper-responsive transition-metal-binding metallothionein proteins (MT1/MT2), consistent with impaired anti-oxidant defences and elevated susceptibility to pro-oxidant stress. Levels of the high-affinity copper transporter-1 (CTR1) were depressed in diabetes, consistent with impaired membrane copper uptake, and were not modified by TETA which, contrastingly, renormalized myocardial copper and increased levels and cell-membrane localization of the low-affinity copper transporter-2 (CTR2). Diabetes also lowered indexes of intracellular (IC) copper delivery via the copper chaperone for superoxide dismutase (CCS) to its target cuproenzyme, superoxide dismutase-1 (SOD1): this pathway was rectified by TETA treatment, which normalized SOD1 activity with consequent bolstering of anti-oxidant defenses. Furthermore, diabetes depressed levels of additional intracellular copper-transporting proteins, including antioxidant-protein-1 (ATOX1) and copper-transporting-ATPase-2 (ATP7B), whereas TETA elevated copper-transporting-ATPase-1 (ATP7A). Conclusions Myocardial copper deficiency and defective cellular copper transport/trafficking are revealed as key molecular defects underlying LV impairment in diabetes, and TETA-mediated restoration of copper regulation provides a potential new class of therapeutic molecules for DCM. PMID:24927960

2014-01-01

400

The possible role of metallothioneins in copper tolerance of Silene cucubalus  

Microsoft Academic Search

Growth and copper-binding of a copper-tolerant and a copper-sensitive population of Silene cucubalus (L.) Wib. have been studied. The copper-tolerant plants showed a much lower uptake and a proportionally higher transport of copper from root to shoot. A copper-binding protein with an apparent Mr of 8500 resembling metallothionein has been isolated from the roots of copper-treated plants of the tolerant

P. C. Lolkema; M. H. Donker; A. J. Schouten; W. H. O. Ernst

1984-01-01

401

Copper toxicity in a New Zealand dairy herd  

PubMed Central

Chronic copper toxicity was diagnosed in a Jersey herd in the Waikato region of New Zealand following an investigation into the deaths of six cattle from a herd of 250 dry cows. Clinical signs and post-mortem examination results were consistent with a hepatopathy, and high concentrations of copper in liver and blood samples of clinically affected animals confirmed copper toxicity. Liver copper concentrations and serum gamma-glutamyl transferase activities were both raised in a group of healthy animals sampled at random from the affected herd, indicating an ongoing risk to the remaining cattle; these animals all had serum copper concentrations within normal limits. Serum samples and liver biopsies were also collected and assayed for copper from animals within two other dairy herds on the same farm; combined results from all three herds showed poor correlation between serum and liver copper concentrations. To reduce liver copper concentrations the affected herd was drenched with 0.5 g ammonium molybdate and 1 g sodium sulphate per cow for five days, and the herd was given no supplementary feed or mineral supplements. Liver biopsies were repeated 44 days after the initial biopsies (approximately 1 month after the end of the drenching program); these showed a significant 37.3% decrease in liver copper concentrations (P <0.02). Also there were no further deaths after the start of the drenching program. Since there was no control group it is impossible to quantify the effect of the drenching program in this case, and dietary changes were also made that would have depleted liver copper stores. Historical analysis of the diet was difficult due to poor record keeping, but multiple sources of copper contributed to a long term copper over supplementation of the herd; the biggest source of copper was a mineral supplement. The farmer perceived this herd to have problems with copper deficiency prior to the diagnosis of copper toxicity, so this case demonstrates the importance of monitoring herd copper status regularly. Also the poor correlation between liver and serum copper concentrations in the three herds sampled demonstrates the importance of using liver copper concentration to assess herd copper status. PMID:25279139

2014-01-01

402

A Study of the Optimal Model of the Flotation Kinetics of Copper Slag from Copper Mine BOR  

NASA Astrophysics Data System (ADS)

In this study the effect of mixtures of copper slag and flotation tailings from copper mine Bor, Serbia on the flotation results of copper recovery and flotation kinetics parameters in a batch flotation cell has been investigated. By simultaneous adding old flotation tailings in the ball mill at the rate of 9%, it is possible to increase copper recovery for about 20%. These results are compared with obtained copper recovery of pure copper slag. The results of batch flotation test were fitted by MatLab software for modeling the first-order flotation kinetics in order to determine kinetics parameters and define an optimal model of the flotation kinetics. Six kinetic models are tested on the batch flotation copper recovery against flotation time. All models showed good correlation, however the modified Kelsall model provided the best fit.

Stanojlovi?, Rodoljub D.; Sokolovi?, Jovica M.

2014-10-01

403

Pronounced site preference and mixed dinuclear dichalcogenide anions (SSe)2- in ternary lanthanum sulfide selenides - The solid solution LaS1.9-LaSe1.9  

NASA Astrophysics Data System (ADS)

Ternary lanthanum sulfide selenides LaS1.9-xSex (0 < x < 1.9) were obtained by reaction of the elements in a potassium bromide flux. The ternary compounds adopt the CeSe1.9 structure type (tetragonal, space group P42/n, No. 86) and form a complete solid solution series without indications of ordered superstructures. The lattice parameters of the samples follow Vegard's rule and are found in the range of 915 ? a ? 943 pm and 1644 ? c ? 1703 pm. A pronounced ordering of the distribution of chalcogen atoms is observed which can be attributed to charge density and size effects. The existence of three different types of dichalcogenide anions, namely S22-, Se22- and mixed (SSe)2-, is evidenced by Raman spectroscopy.

Bartsch, Christian; Doert, Thomas

2012-04-01

404

The gadolinium nitride selenides Gd3NSe3 and Gd23N5Se27: Three connectivity types of [NGd4]9+ tetrahedra and fivefold coordinated Gd3+ cations  

NASA Astrophysics Data System (ADS)

The gadolinium nitride selenides Gd3NSe3 and Gd23N5Se27 are formed by the reaction of gadolinium metal with its triiodide, cesium azide and selenium along with an excess of cesium iodide as flux within seven days at 900 °C in torch-sealed evacuated silica ampoules. The dominant phase Gd3NSe3 crystallizes isotypically with Sm3NS3 in the orthorhombic space group Pnma (unit cell: a = 1256.71(9) pm, b = 398.65(3) pm, c = 1318.32(9) pm, Z = 4). Thus nitride-centered (Gd4)12+ tetrahedra are linked via two vertices each forming {[}?1 chains (t = terminal, v = vertex-shared) along [010], which become interconnected by three crystallographically different Se2- anions. Beside C-type of Gd2Se3 and at least another unknown phase powder diffraction experiments show additional reflections indicating the second nitride selenide Gd23N5Se27. This new compound crystallizes non-centrosymmetrically in the monoclinic space group Pc (unit cell: a = 2854.87(19) pm, b = 1227.94(8) pm, c = 747.62(5) pm, ? = 94.215(3)°, Z = 2). Here, {(}?2 and {(}?2 layers embed the main structural features of isolated [NGd4]9+ tetrahedra and isolated congonial [N2Gd6]12+ bitetrahedra. Another particularity is the fivefold coordination of the (Gd4)3+ cations with one short contact to N3- and four relatively short bonds to four Se2- anions, respectively.

Schurz, Christian M.; Talmon-Gros, Pia; Lissner, Falk; Schleid, Thomas

2013-03-01

405

A Multinuclear Copper(I) Cluster Forms the Dimerization Interface in Copper-Loaded Human Copper Chaperone for Superoxide Dismutase  

SciTech Connect

Copper binding and X-ray aborption spectroscopy studies are reported on untagged human CCS (hCCS; CCS = copper chaperone for superoxide dismutase) isolated using an intein self-cleaving vector and on single and double Cys to Ala mutants of the hCCS MTCQSC and CSC motifs of domains 1 (D1) and 3 (D3), respectively. The results on the wild-type protein confirmed earlier findings on the CCS-MBP (maltose binding protein) constructs, namely, that Cu(I) coordinates to the CXC motif, forming a cluster at the interface of two D3 polypeptides. In contrast to the single Cys to Ser mutations of the CCS-MBP protein (Stasser, J. P., Eisses, J. F., Barry, A. N., Kaplan, J. H., and Blackburn, N. J. (2005) Biochemistry 44, 3143-3152), single Cys to Ala mutations in D3 were sufficient to eliminate cluster formation and significantly reduce CCS activity. Analysis of the intensity of the Cu-Cu cluster interaction in C244A, C246A, and C244/246A variants suggested that the nuclearity of the cluster was greater than 2 and was most consistent with a Cu4S6 adamantane-type species. The relationship among cluster formation, oligomerization, and metal loading was evaluated. The results support a model in which Cu(I) binding converts the apo dimer with a D2-D2 interface to a new dimer connected by cluster formation at two D3 CSC motifs. The predominance of dimer over tetramer in the cluster-containing species strongly suggests that the D2 dimer interface remains open and available for sequestering an SOD1 monomer. This work implicates the copper cluster in the reactive form and adds detail to the cluster nuclearity and how copper loading affects the oligomerization states and reactivity of CCS for its partner SOD1.

Stasser, J.P.; Siluvai, G.S.; Barry, A.N.; Blackburn, N.J.

2009-06-04

406

Visualizing the metal-binding versatility of copper trafficking sites .  

PubMed

Molecular systems have evolved to permit the safe delivery of copper. Despite extensive studies, many copper site structures involved in copper homeostasis, even for the well-studied metallochaperone Atx1, remain unresolved. Cyanobacteria import copper to their thylakoid compartments for use in photosynthesis and respiration and possess an Atx1 that we show can adopt multiple oligomeric states when metalated, capable of binding up to four copper ions. Two-copper- and four-copper-loaded dimers exist in solution at low micromolar concentrations, and head-to-head and side-to-side arrangements, respectively, can be crystallized, with the latter binding a [Cu(4){mu(2)-S(gamma)(Cys)}(4)Cl(2)](2-) cluster. The His61Tyr mutation on loop 5 weakens head-to-head dimerization, yet a side-to-side dimer binding a similar cluster as in the wild-type protein, but with phenolate coordination, is present. The cognate metal-binding domains (MBDs) of the P-type ATPases CtaA and PacS, which are proposed to donate copper to and accept copper from Atx1, respectively, are monomeric in the presence of copper. The structure of the MBD of Cu(I)-PacS shows a crystallographic trimer arrangement around a [Cu(3){mu(2)-S(gamma)(Cys)}(3){S(gamma)(Cys)}(3)](2-) cluster that is very similar to that found for an alternate form of the His61Tyr Atx1 mutant. Copper transfer from the MBD of CtaA to Atx1 is favorable, but delivery from Atx1 to the MBD of PacS is strongly dependent upon the dimeric form of Atx1. A copper-induced switch in Atx1 dimer structure may have a regulatory role with cluster formation helping to buffer copper. PMID:20726513

Badarau, Adriana; Firbank, Susan J; McCarthy, Andrew A; Banfield, Mark J; Dennison, Christopher

2010-09-14

407

Functional implications of multistage copper binding to the prion protein  

PubMed Central

The prion protein (PrP) is responsible for a group of neurodegenerative diseases called the transmissible spongiform encephalopathies. The normal function of PrP has not yet been discovered, but indirect evidence suggests a linkage to its ability to bind copper. In this article, low-copper-concentration bindings of Cu2+ to PrP are investigated by using a recently developed hybrid density functional theory (DFT)/DFT method. It is found that at the lowest copper concentrations, the binding site consists of 4 histidine residues coordinating the copper through ? imidazole nitrogens. At higher concentrations, 2 histidines are involved in the binding, one of them in the axial position. These results are in good agreement with existing experimental data. Comparison of free energies for all modes of coordination shows that when enough copper is available, the binding sites will spontaneously rearrange to accommodate more copper ions, despite the fact that binding energy per copper ion decreases with concentration. These findings support the hypothesis that PrP acts as a copper buffer in vivo, protecting other proteins from the attachment of copper ions. Using large-scale classical molecular dynamics, we also probe the structure of full-length copper-bound PrP, including its unfolded N-terminal domain. The results show that copper attachment leads to rearrangement of the structure of the Cu-bonded octarepeat region and to development of turns in areas separating copper-bound residues. These turns make the flexible N-terminal domain more rigid and thus more resistant to misfolding. The last result suggests that copper binding plays a beneficial role in the initial stages of prion diseases. PMID:19561303

Hodak, Miroslav; Chisnell, Robin; Lu, Wenchang; Bernholc, J.

2009-01-01

408

Polystyrene films as barrier layers for corrosion protection of copper and copper alloys.  

PubMed

Dip-coated polystyrene layers of sub-micrometre thickness (85-500nm) have been applied on copper and copper alloys (aluminium brass, copper-nickel 70/30), as well as on stainless steel 304, and produced an effective barrier against corrosion and adhesion of corrosion-relevant microorganisms. According to the dynamic wettability measurements, the coatings exhibited high advancing (103°), receding (79°) and equilibrium (87°) contact angles, low contact angle hysteresis (6°) and surface free energy (31mJ/m(2)). The corrosion rate of copper-nickel 70/30 alloy samples in 3.5% NaCl was as low as 3.2?m/a (44% of that of the uncoated samples), and in artificial seawater was only 0.9?m/a (29% of that of the uncoated samples). Cell adhesion was studied by fluorescence microscopy, using monoculture of Desulfovibrio alaskensis. The coatings not only decreased the corrosion rate but also markedly reduced the number of bacterial cells adhered to the coated surfaces. The PS coating on copper gave the best result, 2×10(3)cells/cm(2) (1% of that of the uncoated control). PMID:24239277

Románszki, Loránd; Datsenko, Iaryna; May, Zoltán; Telegdi, Judit; Nyikos, Lajos; Sand, Wolfgang

2014-06-01

409

Cuprizone neurotoxicity, copper deficiency and neurodegeneration.  

PubMed

Cuprizone is used to obtain demyelination in mice. Cuprizone-treated mice show symptoms similar to several neurodegenerative disorders such as severe status spongiosus. Although it has a simple chemical formula, its neurotoxic mechanism is still unknown. In this work, we examined both physico-chemical properties and biological effects of cuprizone. Our results indicate that cuprizone has very complicated and misunderstood solution chemistry. Moreover, we show here the inability of cuprizone to cross neither the intestinal epithelial barrier nor the neuronal cell membrane, as well its high tolerability by cultured neurons. If added to mice diet, cuprizone does not accumulate in liver or in brain. Therefore, its neurotoxic effect is explainable only in terms of its capability to chelate copper, leading to chronic copper deficiency. PMID:20685220

Benetti, Federico; Ventura, Marcello; Salmini, Benedetta; Ceola, Stefano; Carbonera, Donatella; Mammi, Stefano; Zitolo, Andrea; D'Angelo, Paola; Urso, Emanuela; Maffia, Michele; Salvato, Benedetto; Spisni, Enzo

2010-09-01

410

Shock Hugoniot of Single Crystal Copper  

SciTech Connect

The shock Hugoniot of single crystal copper is reported for stresses below 66 GPa. Symmetric impact experiments were used to measure the Hugoniots of three different crystal orientations of copper, [100], [110], [111]. The photonic doppler velocimetry (PDV) diagnostic was adapted into a very high precision time of arrival detector for these experiments. The measured Hugoniots along all three crystal directions were nearly identical to the experimental Hugoniot for polycrystalline Cu. The predicted orientation dependence of the Hugoniot from MD calculations was not observed. At the lowest stresses, the sound speed in Cu was extracted from the PDV data. The measured sound speeds are in agreement with values calculated from the elastic constants for Cu.

Chau, R; Stolken, J; Asoka-Kumar, P; Kumar, M; Holmes, N C

2009-08-28

411

Exploring copper chelation in Alzheimer's disease protein  

NASA Astrophysics Data System (ADS)

Alzheimer's disease (AD) is a neurodegenerative disorder affecting millions of aging people in the U.S. alone. Clinical studies have indicated that metal chelation is a promising new approach in alleviating the symptoms of AD. Our study explores the as yet undetermined mechanism of copper chelation in amyloid-?, a protein implicated in AD. The structure of amyloid-? is derived from experimental results and incorporates a planar copper-ion-binding structure in a semi-solvated state. We investigate the chelation process using the nudged elastic band method implemented in our ab initio real-space multigrid code. We find that an optimal sequence of unbonding and rebonding events as well as proton transfers are required for a viable chelation process. These findings provide fundamental insight into the process of chelation that may lead to more effective AD therapies.

Rose, Frisco; Hodak, Miroslav; Bernholc, Jerry

2012-02-01

412

Precision micro drilling with copper vapor lasers  

SciTech Connect

The authors have developed a copper vapor laser based micro machining system using advanced beam quality control and precision wavefront tilting technologies. Micro drilling has been demonstrated through percussion drilling and trepanning using this system. With a 30 W copper vapor laser running at multi-kHz pulse repetition frequency, straight parallel holes with size varying from 500 microns to less than 25 microns and with aspect ratio up to 1:40 have been consistently drilled on a variety of metals with good quality. For precision trepanned holes, the hole-to-hole size variation is typically within 1% of its diameter. Hole entrance and exit are both well defined with dimension error less than a few microns. Materialography of sectioned holes shows little (sub-micron scale) recast layer and heat affected zone with surface roughness within 1--2 microns.

Chang, J.J.; Martinez, M.W.; Warner, B.E.; Dragon, E.P.; Huete, G.; Solarski, M.E.

1994-09-02

413

Electrodeposition of copper/cuprous oxide nanocomposites  

SciTech Connect

Copper and cuprous oxide can both be electrodeposited from an alkaline solution of a lactate complex of Cu(II). At low applied potentials or currents, pure cuprous oxide is deposited. It is a p-type semiconductor with a bandgap of 1.9 eV (indirect) and a resistivity in the Mohm-cm range. As the potential is driven more negative of about -0.6V vs SCE, a strained nanocomposite of copper and cuprous oxide is deposited. The potential oscillates during galvanostatic deposition, suggesting that the nanocomposites are actually self-assembled multilayers with layers as thin as 10 nm. We expect these materials to have interesting optical and electrical properties, since the films consist of thousands of stacked Schottky barriers.

Switzer, J.A. [Univ. of Missouri, MO (United States)

1996-10-01

414

The Many Faces of the Copper Metabolism Protein MURR1\\/COMMD1  

Microsoft Academic Search

Copper is an essential transition metal but is toxic in excess; therefore, its metabolism needs to be tightly regulated. Defects in the regulation of copper can lead to various disorders characterized by copper deficiency or copper excess. Recently, we characterized the COMMD1 (previously MURR1) gene as the defective gene in canine copper toxicosis. The molecular func- tions of COMMD1 remain

P. de Bie; B. VAN DE SLUIS; L. KLOMP; C. WIJMENGA

2005-01-01

415

Corrosion behaviour of high copper dental amalgams.  

PubMed

This study evaluated the corrosion behaviour of two high copper dental amalgam alloys [Dispersalloy (Dentsply-Caulk) and Tytin (Kerr)] in different electrolytes. Amalgam specimens were prepared, coupled to a copper wire, cemented into glass tubes and polished to a 600-grit finish. A corrosion cell was prepared using a carbon counter-electrode, a standard calomel electrode as the reference and amalgam as the working electrode. The alloys were tested in the following mediums at 37 degrees C: (i) artificial saliva based on Fusayama's solution (FS), (ii) artificial saliva with citric acid adjusted to pH 4.0 (FC) and (iii) 1% sodium chloride solution (SC). Corrosion potentials (E(corr)) and corrosion rates (I(corr)) were determined using potentiostatic and impedance spectroscopy methods. Data was subjected to anova/Scheffe's post hoc test at 0.05 significance level. For both alloys, the corrosion potential in FS was significantly greater than in SC. Corrosion potential of Tytin in FS and SC was also significantly greater than in FC. The corrosion rate of Dispersalloy in FC was significantly greater than in FS and SC. For Tytin, corrosion rate in SC was significantly greater than in FS and FC. Although no significant difference in corrosion potential/rate was observed between the alloys when tested in FS, significant differences were observed when electrochemical testing was carried out in FC and SC. The corrosion behaviour of high copper amalgam alloys are both material and environment dependent. Certain food substances may increase the corrosion of high copper amalgams. PMID:15189319

Yap, A U J; Ng, B L; Blackwood, D J

2004-06-01

416

Atomistic insights into aqueous corrosion of copper  

NASA Astrophysics Data System (ADS)

Corrosion is a fundamental problem in electrochemistry and represents a mode of failure of technologically important materials. Understanding the basic mechanism of aqueous corrosion of metals such as Cu in presence of halide ions is hence essential. Using molecular dynamics simulations incorporating reactive force-field (ReaxFF), the interaction of copper substrates and chlorine under aqueous conditions has been investigated. These simulations incorporate effects of proton transfer in the aqueous media and are suitable for modeling the bond formation and bond breakage phenomenon that is associated with complex aqueous corrosion phenomena. Systematic investigation of the corrosion process has been carried out by simulating different chlorine concentration and solution states. The structural and morphological differences associated with metal dissolution in the presence of chloride ions are evaluated using dynamical correlation functions. The simulated atomic trajectories are used to analyze the charged states, molecular structure and ion density distribution which are utilized to understand the atomic scale mechanism of corrosion of copper substrates under aqueous conditions. Increased concentration of chlorine and higher ambient temperature were found to expedite the corrosion of copper. In order to study the effect of solution states on the corrosion resistance of Cu, partial fractions of proton or hydroxide in water were configured, and higher corrosion rate at partial fraction hydroxide environment was observed. When the Cl- concentration is low, oxygen or hydroxide ion adsorption onto Cu surface has been confirmed in partial fraction hydroxide environment. Our study provides new atomic scale insights into the early stages of aqueous corrosion of metals such as copper.

Jeon, Byoungseon; Sankaranarayanan, Subramanian K. R. S.; van Duin, Adri C. T.; Ramanathan, Shriram

2011-06-01

417

Atomistic insights into aqueous corrosion of copper.  

PubMed

Corrosion is a fundamental problem in electrochemistry and represents a mode of failure of technologically important materials. Understanding the basic mechanism of aqueous corrosion of metals such as Cu in presence of halide ions is hence essential. Using molecular dynamics simulations incorporating reactive force-field (ReaxFF), the interaction of copper substrates and chlorine under aqueous conditions has been investigated. These simulations incorporate effects of proton transfer in the aqueous media and are suitable for modeling the bond formation and bond breakage phenomenon that is associated with complex aqueous corrosion phenomena. Systematic investigation of the corrosion process has been carried out by simulating different chlorine concentration and solution states. The structural and morphological differences associated with metal dissolution in the presence of chloride ions are evaluated using dynamical correlation functions. The simulated atomic trajectories are used to analyze the charged states, molecular structure and ion density distribution which are utilized to understand the atomic scale mechanism of corrosion of copper substrates under aqueous conditions. Increased concentration of chlorine and higher ambient temperature were found to expedite the corrosion of copper. In order to study the effect of solution states on the corrosion resistance of Cu, partial fractions of proton or hydroxide in water were configured, and higher corrosion rate at partial fraction hydroxide environment was observed. When the Cl(-) concentration is low, oxygen or hydroxide ion adsorption onto Cu surface has been confirmed in partial fraction hydroxide environment. Our study provides new atomic scale insights into the early stages of aqueous corrosion of metals such as copper. PMID:21702575

Jeon, Byoungseon; Sankaranarayanan, Subramanian K R S; van Duin, Adri C T; Ramanathan, Shriram

2011-06-21

418

New Technology for Electrorefining of Copper  

NASA Astrophysics Data System (ADS)

New electrorefining technology utilizes a novel manifold electrolyte inlet, which allows improving productivity and production in new and existing tankhouses at high current efficiency and very good cathode quality. Two installation examples—Montanwerke Brixlegg AG, Brixlegg, Austria (upgrade existing tankhouse) and Xiangguang Copper, Yanggu, China (new tankhouse)—demonstrate the use of current densities above 400 A/m2 at very high current efficiency in electrorefining.

Filzwieser, Andreas; Filzwieser, Iris; Konetschnik, Stefan

2012-11-01

419

Atomistic insights into aqueous corrosion of copper.  

SciTech Connect

Corrosion is a fundamental problem in electrochemistry and represents a mode of failure of technologically important materials. Understanding the basic mechanism of aqueous corrosion of metals such as Cu in presence of halide ions is hence essential. Using molecular dynamics simulations incorporating reactive force-field (ReaxFF), the interaction of copper substrates and chlorine under aqueous conditions has been investigated. These simulations incorporate effects of proton transfer in the aqueous media and are suitable for modeling the bond formation and bond breakage phenomenon that is associated with complex aqueous corrosion phenomena. Systematic investigation of the corrosion process has been carried out by simulating different chlorine concentration and solution states. The structural and morphological differences associated with metal dissolution in the presence of chloride ions are evaluated using dynamical correlation functions. The simulated atomic trajectories are used to analyze the charged states, molecular structure and ion density distribution which are utilized to understand the atomic scale mechanism of corrosion of copper substrates under aqueous conditions. Increased concentration of chlorine and higher ambient temperature were found to expedite the corrosion of copper. In order to study the effect of solution states on the corrosion resistance of Cu, partial fractions of proton or hydroxide in water were configured, and higher corrosion rate at partial fraction hydroxide environment was observed. When the Cl{sup -} concentration is low, oxygen or hydroxide ion adsorption onto Cu surface has been confirmed in partial fraction hydroxide environment. Our study provides new atomic scale insights into the early stages of aqueous corrosion of metals such as copper.

Jeon, B.; Sankaranarayanan, S. K. R. S.; van Duin, A. C. T.; Ramanathan, S. (Center for Nanoscale Materials); (Harvard Univ.); (Penn State Univ.)

2011-06-21

420

Copper vapor laser modular packaging assembly  

DOEpatents

A modularized packaging arrangement for one or more copper vapor lasers and associated equipment is disclosed herein. This arrangement includes a single housing which contains the laser or lasers and all their associated equipment except power, water and neon, and means for bringing power, water, and neon which are necessary to the operation of the lasers into the container for use by the laser or lasers and their associated equipment. 2 figs.

Alger, T.W.; Ault, E.R.; Moses, E.I.

1992-12-01

421

Superconductivity in a layered perovskite without copper  

Microsoft Academic Search

FOLLOWING the discovery of superconductivity at ~30 K in La2-xBaxCuO4 (ref. 1), a large number of related compounds have been found that are superconducting at relatively high temperatures. The feature common to all of these materials is a layered crystal structure based on a perovskite template and containing planar networks of copper and oxygen. This raises the question of whether

Y. Maeno; H. Hashimoto; K. Yoshida; S. Nishizaki; T. Fujita; J. G. Bednorz; F. Lichtenberg

1994-01-01

422

Copper Homeostasis in Salmonella Is Atypical and Copper-CueP Is a Major Periplasmic Metal Complex*  

PubMed Central

Salmonella enterica sv. typhimurium (S. enterica sv. Typhimurium) has two metal-transporting P1-type ATPases whose actions largely overlap with respect to growth in elevated copper. Mutants lacking both ATPases over-accumulate copper relative to wild-type or either single mutant. Such duplication of ATPases is unusual in bacterial copper tolerance. Both ATPases are under the control of MerR family metal-responsive transcriptional activators. Analyses of periplasmic copper complexes identified copper-CueP as one of the predominant metal pools. Expression of cueP was recently shown to be controlled by the same metal-responsive activator as one of the P1-type ATPase genes (copA), and copper-CueP is a further atypical feature of copper homeostasis in S. enterica sv. Typhimurium. Elevated copper is detected by a reporter construct driven by the promoter of copA in wild-type S. enterica sv. Typhimurium during infection of macrophages. Double mutants missing both ATPases also show reduced survival inside cultured macrophages. It is hypothesized that elevated copper within macrophages may have selected for specialized copper-resistance systems in pathogenic microorganism such as S. enterica sv. Typhimurium. PMID:20534583

Osman, Deenah; Waldron, Kevin J.; Denton, Harriet; Taylor, Clare M.; Grant, Andrew J.; Mastroeni, Pietro; Robinson, Nigel J.; Cavet, Jennifer S.

2010-01-01

423

Crystal structures of copper(II) nitrate, copper(II) chloride, and copper(II) perchlorate complexes with 2-formylpyridine semicarbazone  

SciTech Connect

Compounds dinitrato(2-formylpyridinesemicarbazone)copper (I), dichloro(2-formylpyridinesemicarbazone) copper hemihydrate (II), and bis(2-formylpyridinesemicarbazone)copper(2+) perchlorate hydrate (III) are synthesized and their crystal structures are determined. In compounds I-III, the neutral 2-formylpyridine semicarbazone molecule (L) is tridentately attached to the copper atom via the N,N,O set of donor atoms. In compounds I and II, the Cu: L ratio is equal to 1: 1, whereas, in III, it is 1: 2. In complex I, the coordination sphere of the copper atom includes two nitrate ions with different structural functions in addition to the L ligand. The structure is built as a one-dimensional polymer in which the NO{sub 3} bidentate group fulfills a bridging function. The coordination polyhedron of the copper(2+) atom can be considered a distorted tetragonal bipyramid (4 + 1 + 1). Compound II has an ionic structure in which the main element is the [CuLCl{sub 2} . Cu(H{sub 2}O)LCl]{sup +} dimer. In the dimer, the copper atoms are linked via one of the {mu}{sub 2}-bridging chlorine atoms. The coordination polyhedra of the central atoms of the Cu(H{sub 2})LCl and CuLCl{sub 2} complex fragments are tetragonal bipyramid and tetragonal pyramid, respectively. In compound III, the copper atom is octahedrally surrounded by two L ligands in the mer configuration.

Chumakov, Yu. M. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Tsapkov, V. I. [State University of Moldova (Moldova, Republic of); Antosyak, B. Ya. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Bairac, N. N. [State University of Moldova (Moldova, Republic of); Simonov, Yu. A., E-mail: simonov.xray@phys.asm.md [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Bocelli, G. [National Research Council (IMEM-CNR), Institute of Materials for Electronics and Magnetism (Italy); Pahontu, E. [University of Medicine and Pharmacy (Romania); Gulea, A. P. [State University of Moldova (Moldova, Republic of)

2009-05-15

424

Copper stabilizes the Menkes copper-transporting ATPase (Atp7a) protein expressed in rat intestinal epithelial cells  

PubMed Central

Iron deficiency decreases oxygen tension in the intestinal mucosa, leading to stabilization of hypoxia-inducible transcription factor 2? (Hif2?) and subsequent upregulation of genes involved in iron transport [e.g., divalent metal transporter (Dmt1) and ferroportin 1 (Fpn1)]. Iron deprivation also alters copper homeostasis, reflected by copper accumulation in the intestinal epithelium and induction of an intracellular copper-binding protein [metallothionein (Mt)] and a copper exporter [Menkes copper ATPase (Atp7a)]. Importantly, Atp7a is also a Hif2? target. It was, however, previously noted that Atp7a protein expression was induced more strongly than mRNA in the duodenum of iron-deprived rats, suggesting additional regulatory mechanisms. The current study was thus designed to decipher mechanistic aspects of Atp7a regulation during iron deprivation using an established in vitro model of the mammalian intestine, rat intestinal epithelial (IEC-6) cells. Cells were treated with an iron chelator and/or copper loaded to mimic the in vivo situation. IEC-6 cells exposed to copper showed a dose-dependent increase in Mt expression, confirming intracellular copper accumulation. Iron chelation with copper loading increased Atp7a mRNA and protein levels; however, contrary to our expectation, copper alone increased only protein levels. This suggested that copper increased Atp7a protein levels by a posttranscriptional regulatory mechanism. Therefore, to determine if Atp7a protein stability was affected, the translation inhibitor cycloheximide was utilized. Experiments in IEC-6 cells revealed that the half-life of the Atp7a protein was ?41 h and, furthermore, that intracellular copper accumulation increased steady-state Atp7a protein levels. This investigation thus reveals a novel mechanism of Atp7a regulation in which copper stabilizes the protein, possibly complementing Hif2?-mediated transcriptional induction during iron deficiency. PMID:23174565

Xie, Liwei

2013-01-01

425

Copper oxide nanowires: a review of growth  

NASA Astrophysics Data System (ADS)

Cuprous oxide (Cu2O) and cupric oxide (CuO) nanowires have started playing important roles in energy conversion devices and optoelectronic devices. Although the desired advanced properties have been demonstrated, these materials cannot yet be produced in large-bulk quantities in order to bridge the technological transfer gap for wider use. In this respect, the quest for the most efficient synthesis process which yields not only large quantities but also high quality and advanced material properties continues. This paper gives an extensive review of copper oxide nanowire (NW) synthesis by all methods and routes by which various researchers have obtained their nanomaterial. These methods are critically overviewed, evaluated and compared. Methods of copper oxide NW growth include wet-chemical methods based on pure solution growth, electrochemical and hydrothermal routes as well as thermal and plasma oxidation methods. In terms of advanced nanowire synthesis, the fast thermal method or direct plasma oxidation as well as the combined hybrid wet-chemical method in which copper hydroxide NWs are produced and sequentially transformed by plasma oxidation which produces Cu2O NWs are seen as the most promising methods to explore in the near future. These methods not only yield large quantities of NWs, but produce high quality material with advanced properties.

Filipi?, G.; Cvelbar, U.

2012-05-01

426

Copper oxide nanowires: a review of growth.  

PubMed

Cuprous oxide (Cu(2)O) and cupric oxide (CuO) nanowires have started playing important roles in energy conversion devices and optoelectronic devices. Although the desired advanced properties have been demonstrated, these materials cannot yet be produced in large-bulk quantities in order to bridge the technological transfer gap for wider use. In this respect, the quest for the most efficient synthesis process which yields not only large quantities but also high quality and advanced material properties continues. This paper gives an extensive review of copper oxide nanowire (NW) synthesis by all methods and routes by which various researchers have obtained their nanomaterial. These methods are critically overviewed, evaluated and compared. Methods of copper oxide NW growth include wet-chemical methods based on pure solution growth, electrochemical and hydrothermal routes as well as thermal and plasma oxidation methods. In terms of advanced nanowire synthesis, the fast thermal method or direct plasma oxidation as well as the combined hybrid wet-chemical method in which copper hydroxide NWs are produced and sequentially transformed by plasma oxidation which produces Cu(2)O NWs are seen as the most promising methods to explore in the near future. These methods not only yield large quantities of NWs, but produce high quality material with advanced properties. PMID:22538410

Filipi?, G; Cvelbar, U

2012-05-17

427

Antiinflammatory reactivity of copper(I)-thionein  

SciTech Connect

In unseparated human blood the reactivity of yeast copper (I)-thionein on TPA-activated polymorphonuclear leukocytes was evaluated and compared with low Mr copper chelates exerting Cu2Zn2 superoxide dismutase mimetic activity. Cu, 18 microM, in the form of Cu-thionein was sufficient to inhibit the superoxide production of activated human blood phagocytes by 50%. Furthermore, the scavenging of hydroxyl radicals and singlet oxygen by Cu(I)-thionein was determined, using the 2-deoxyribose fragmentation assay induced by decaying K3CrO8 and the NADPH oxidation caused by UVA illuminated psoralen, respectively. The inhibitory reactivity of Cu-thionein in both assays was compared with that of serum proteins including albumin, ceruloplasmin, transferrin, and ferritin. The galactosamine/endotoxin-induced hepatitis in male NMRI mice was used to evaluate the antiinflammatory reactivity of Cu-thionein in vivo. The serum copper, superoxide dismutase, and sorbitol dehydrogenase concentrations, as well as the activity of polymorphonuclear leukocytes in unseparated blood seemed most appropriate to quantify the protective capacity of Cu-thionein in the course of an oxidative stress-dependent liver injury. The intraperitoneal application of 32.5 mumols/kg thionein-Cu limited this damage to 45%.

Miesel, R.; Hartmann, H.J.; Weser, U. (Universitaet Tuebingen (Germany, F.R.))

1990-10-01

428

Gold, nickel and copper mining and processing.  

PubMed

Ore mining occurs in all Canadian provinces and territories except Prince Edward Island. Ores include bauxite, copper, gold, iron, lead and zinc. Workers in metal mining and processing are exposed, not only to the metal of interest, but also to various other substances prevalent in the industry, such as diesel emissions, oil mists, blasting agents, silica, radon, and arsenic. This chapter examines cancer risk related to the mining of gold, nickel and copper. The human carcinogenicity of nickel depends upon the species of nickel, its concentration and the route of exposure. Exposure to nickel or nickel compounds via routes other than inhalation has not been shown to increase cancer risk in humans. As such, cancer sites of concern include the lung, and the nasal sinus. Evidence comes from studies of nickel refinery and leaching, calcining, and sintering workers in the early half of the 20th century. There appears to be little or no detectable risk in most sectors of the nickel industry at current exposure levels. The general population risk from the extremely small concentrations detectable in ambient air are negligible. Nevertheless, animal carcinogenesis studies, studies of nickel carcinogenesis mechanisms, and epidemiological studies with quantitative exposure assessment of various nickel species would enhance our understanding of human health risks associated with nickel. Definitive conclusions linking cancer to exposures in gold and copper mining and processing are not possible at this time. The available results appear to demand additional study of a variety of potential occupational and non-occupational risk factors. PMID:21199602

Lightfoot, Nancy E; Pacey, Michael A; Darling, Shelley

2010-01-01

429

Copper Homeostasis at the Host-Pathogen Interface*  

PubMed Central

The trace element copper is indispensable for all aerobic life forms. Its ability to cycle between two oxidation states, Cu1+ and Cu2+, has been harnessed by a wide array of metalloenzymes that catalyze electron transfer reactions. The metabolic needs for copper are sustained by a complex series of transporters and carrier proteins that regulate its intracellular accumulation and distribution in both pathogenic microbes and their animal hosts. However, copper is also potentially toxic due in part to its ability to generate reactive oxygen species. Recent studies suggest that the macrophage phagosome accumulates copper during bacterial infection, which may constitute an important mechanism of killing. Bacterial countermeasures include the up-regulation of copper export and detoxification genes during infection, which studies suggest are important determinants of virulence. In this minireview, we summarize recent developments that suggest an emerging role for copper as an unexpected component in determining the outcome of host-pathogen interactions. PMID:22389498

Hodgkinson, Victoria; Petris, Michael J.

2012-01-01

430

Copper in silicon: Quantitative analysis of internal and proximity gettering  

SciTech Connect

The behavior of copper in the presence of a proximity gettering mechanism and a standard internal gettering mechanism in silicon was studied. He implantation-induced cavities in the near surface region were used as a proximity gettering mechanism and oxygen precipitates in the bulk of the material provided internal gettering sites. Moderate levels of copper contamination were introduced by ion implantation such that the copper was not supersaturated during the anneals, thus providing realistic copper contamination/gettering conditions. Copper concentrations at cavities and internal gettering sites were quantitatively measured after the annealings. In this manner, the gettering effectiveness of cavities was measured when in direct competition with internal gettering sites. The cavities were found to be the dominant gettering mechanism with only a small amount of copper gettered at the internal gettering sites. These results reveal the benefits of a segregation-type gettering mechanism for typical contamination conditions.

McHugo, S.A. [Lawrence Berkeley National Lab., CA (United States); Flink, C.; Weber, E.R. [Univ. of California, Berkeley, CA (United States)] [and others

1997-08-01

431

Prevention of anemia alleviates heart hypertrophy in copper deficient rats  

SciTech Connect

The present investigation was designed to examine the role of anemia in the cardiomegaly and myocardial pathology of copper deficiency. Weanling rats were fed a copper deficient diet containing either starch (ST) or fructose (FRU) for five weeks. Six rats consuming the FRU diet were intraperitoneally injected once a week with 1.0 ml/100g bw of packed red blood cells (RBC) obtained from copper deficient rats fed ST. FRU rats injected with RBC did not develop anemia. Additionally, none of the injected rats exhibited heart hypertrophy or gross pathology and all survived. In contrast, non-injected FRU rats were anemic, exhibited severe signs of copper deficiency which include heart hypertrophy with gross pathology, and 44% died. Maintaining the hematocrit with RBC injections resulted in normal heart histology and prevented the mortality associated with the fructose x copper interaction. The finding suggest that the anemia associated with copper deficiency contributes to heart pathology.

Lure, M.D.; Fields, M.; Lewis, C.G. (Dept. of Agriculture, Beltsville, MD (United States) Univ. of Maryland, College Park (United States) Georgetown Univ., Washington, DC (United States))

1991-03-11

432

Transition-metal prion protein attachment: Competition with copper  

NASA Astrophysics Data System (ADS)

Prion protein, PrP, is a protein capable of binding copper ions in multiple modes depending on their concentration. Misfolded PrP is implicated in a group of neurodegenerative diseases, which include ``mad cow disease'' and its human form, variant Creutzfeld-Jacob disease. An increasing amount of evidence suggests that attachment of non-copper metal ions to PrP triggers transformations to abnormal forms similar to those observed in prion diseases. In this work, we use hybrid Kohn-Sham/orbital-free density functional theory simulations to investigate copper replacement by other transition metals that bind to PrP, including zinc, iron and manganese. We consider all known copper binding modes in the N-terminal domain of PrP. Our calculations identify modes most susceptible to copper replacement and reveal metals that can successfully compete with copper for attachment to PrP.

Hodak, Miroslav; Bernholc, Jerry

2012-02-01

433

Toxicity of Copper and Ascorbic Acid to Serratia marcescens  

PubMed Central

Zimmerman, Leonard (Fort Detrick, Frederick, Md.). Toxicity of copper and ascorbic acid to Serratia marcescens. J. Bacteriol. 91:1537–1542. 1966.—Neutral solutions of ascorbic acid were antibacterial to Serratia marcescens at low but not at high population densities. The toxicity of ascorbate was eliminated by metal-sequestering treatments, and was restored only by the addition of trace amounts of copper salts. Copper-ascorbate was equally toxic under aerobic or anaerobic conditions; its toxicity was abolished by (i) chelating agents that sequestered the copper, (ii) metal-complexing agents that bound to the cells but did not sequester copper, and (iii) iron salts in the presence of air. On the basis of these observations, the toxic effects of copper-ascorbate were attributed to its reaction with vital Fe-containing cellular components. PMID:5326115

Zimmerman, Leonard

1966-01-01

434

Toxic effect of copper on Oscillatoria (Trichodesmium) theibautii  

Microsoft Academic Search

(¹⁴C)COâ fixation in Oscillatoria theibautii decreased in response to copper at low cupric ion activities (10⁻¹° M) in test media containing Tris as a copper chelator and to low concentrations (10⁻⁸ M) of total added copper in filtered seawater. This sensitivity could be important to natural systems as well as laboratory and shipboard cultures.

JOHN G. RUETER; JAMES J. MCCARTHY; EDWARD J. CARPENTER

1979-01-01

435

Resistance mechanisms of Mycobacterium tuberculosis against phagosomal copper overload  

PubMed Central

SUMMARY Mycobacterium tuberculosis is an important bacterial pathogen with an extremely slow growth rate, an unusual outer membrane of very low permeability and a cunning ability to survive inside the human host despite a potent immune response. A key trait of M. tuberculosis is to acquire essential nutrients while still preserving its natural resistance to toxic compounds. In this regard, copper homeostasis mechanisms are particularly interesting, because copper is an important element for bacterial growth, but copper overload is toxic. In M. tuberculosis at least two enzymes require copper as a cofactor: the Cu/Zn-superoxide dismutase SodC and the cytochrome c oxidase which is essential for growth in vitro. Mutants of M. tuberculosis lacking the copper metallothionein MymT, the efflux pump CtpV and the membrane protein MctB are more susceptible to copper indicating that these proteins are part of a multipronged system to balance intracellular copper levels. Recent evidence showed that part of copper toxicity is a reversible damage of accessible Fe-S clusters of dehydratases and the displacement of other divalent cations such as zinc and manganese as cofactors in proteins. There is accumulating evidence that macrophages use copper to poison bacteria trapped inside phagosomes. Here, we review the rapidly increasing knowledge about copper homeostasis mechanisms in M. tuberculosis and contrast those with similar mechanisms in E. coli. These findings reveal an intricate interplay between the host which aims to overload the phagosome with copper and M. tuberculosis which utilizes several mechanisms to reduce the toxic effects of excess copper. PMID:22361385

Rowland, Jennifer L.; Niederweis, Michael

2012-01-01

436

Managing the Use of Copper-Based Antifouling Paints  

NASA Astrophysics Data System (ADS)

Copper is the biocide of choice for present-day antifouling (AF) paints. It is also a major source of copper loading in to the marine environment and, as such, might cause local copper levels to exceed water quality criteria. The present study is multifaceted and looks into the overall impact of copper-based AF paints on copper concentrations along a 64-km stretch of the Indian River Lagoon and at Port Canaveral, Florida. This preliminary study is one of the first to outline issues and present background evidence on the current status of copper and copper-based AF usage in Florida and to address the need for management. Previous measurements of copper levels in these waters show a history of copper contamination close to marinas, boatyards, and at Port Canaveral that often exceed state and federal water quality standards. Further, we estimate that the total annual copper input into the Indian River Lagoon is between 1.7 tons/year (sailboats) and 2.1 tons/year (powerboats) from boats in 14 marinas. We estimate the copper input into Port Canaveral to be about 1.4 tons/year from seven cruise ships. A brief survey of marina operators and boat owners revealed attitudes and practices associated with AF paint usage that ranged from excellent to inferior. Management recommendations are made for a proactive approach to improving AF paint selection and application, assessing the environmental status of copper, and redefining existing management practices for sustainable AF paint usage and environmental health.

Srinivasan, Mridula; Swain, Geoffrey W.

2007-03-01

437

Synthesis of copper dendrite nanostructures by a sonoelectrochemical method.  

PubMed

Copper dendrites have been prepared by a sonoelectrochemical process from an aqueous solution of Cu(2+) in the presence of polyvinyl alcohol. A SEM image of the morpholohy of the copper formed on the electrode after one electric pulse is presented. A subsequent sonic pulse removes the copper from the electrode surface, cleaning it for the next step. The formation of the dendrites is accounted for by the "drying-mediated self-assembly of nanoparticles" theory. PMID:18386304

Haas, Iris; Shanmugam, Sangaraju; Gedanken, Aharon

2008-01-01

438

Using polyethylene glycols as alternative inhibitors in copper electrorefining  

NASA Astrophysics Data System (ADS)

Polyethylene glycols (PEGs) with well-defined molecular weight ranges are interesting alternative additives for copper electrorefining. In comparison to glue, PEGs offer high thermal stability and slow chemical decomposition at higher temperatures, with high cathodic polarization. Thosefactors are advantages for an optimized process control in copper electrorefining. Investigations into cathodic polarization as a function of molecular weight and concentration at 500 A/m2, and also into the half-life of PEGs, were conducted in typical copper electrolyte.

Stelter, Michael; Bombach, Hartmut; Nesterov, Nikolay

2002-04-01

439

Morphological differences in bromeliad leaf surfaces: influence on copper uptake  

E-print Network

t fth g a~NB tf . f d by scanning electron microscopy to determine characteristics of trichome morphology and distribution. Comparisons made between proximal and distal regions of the adaxial surfaces revealed differ- ences in the number of peltate... trichomes among the four species. These trichome concentrations were contrasted with copper absorption data. No direct correlation between high trichome density and high copper absorption was shown by this comparison. However, definite copper absorption...

Fisher, Barbara Dee

1978-01-01

440

Copper signaling axis as a target for prostate cancer therapeutics.  

PubMed

Previously published reports indicate that serum copper levels are elevated in patients with prostate cancer and that increased copper uptake can be used as a means to image prostate tumors. It is unclear, however, to what extent copper is required for prostate cancer cell function as we observed only modest effects of chelation strategies on the growth of these cells in vitro. With the goal of exploiting prostate cancer cell proclivity for copper uptake, we developed a "conditional lethal" screen to identify compounds whose cytotoxic actions were manifested in a copper-dependent manner. Emerging from this screen was a series of dithiocarbamates, which, when complexed with copper, induced reactive oxygen species-dependent apoptosis of malignant, but not normal, prostate cells. One of the dithiocarbamates identified, disulfiram (DSF), is an FDA-approved drug that has previously yielded disappointing results in clinical trials in patients with recurrent prostate cancer. Similarly, in our studies, DSF alone had a minimal effect on the growth of prostate cancer tumors when propagated as xenografts. However, when DSF was coadministered with copper, a very dramatic inhibition of tumor growth in models of hormone-sensitive and of castrate-resistant disease was observed. Furthermore, we determined that prostate cancer cells express high levels of CTR1, the primary copper transporter, and additional chaperones that are required to maintain intracellular copper homeostasis. The expression levels of most of these proteins are increased further upon treatment of androgen receptor (AR)-positive prostate cancer cell lines with androgens. Not surprisingly, robust CTR1-dependent uptake of copper into prostate cancer cells was observed, an activity that was accentuated by activation of AR. Given these data linking AR to intracellular copper uptake, we believe that dithiocarbamate/copper complexes are likely to be effective for the treatment of patients with prostate cancer whose disease is resistant to classical androgen ablation therapies. PMID:25320179

Safi, Rachid; Nelson, Erik R; Chitneni, Satish K; Franz, Katherine J; George, Daniel J; Zalutsky, Michael R; McDonnell, Donald P

2014-10-15