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1

Cadmium, zinc, copper, and barium in foraminifera tests  

NASA Astrophysics Data System (ADS)

The concentrations of cadmium, zinc, copper and barium have been determined on 2-mg samples of single-species foraminifera populations. Cleaning techniques were tested using North Atlantic core tops, and followed by a detailed downcore study for the last 30,000 years in South Atlantic core V22-174. Raw foram tests cleaned by crushing followed by ultrasonic removal of fine-grained material, and dissolved in a pH 5.5 acetate buffer, contain appreciable amounts of trace elements associated with ferromanganese and alumino-silicate contaminants. A reductive/complexing cleaning treatment reduces ferromanganese contamination by 1-2 orders of magnitude. Acetate buffers at pH 5.5 complex iron and raise the solubility of ferromanganese oxides; these buffers are unsuitable for separating carbonate lattice-bound trace elements from the fraction associated with ferromanganese phases. Improved mechanical and ultrasonic reductive cleaning combined with a mild dissolution in distilled water under 1 atm. P CO 2 reduces contaminant levels another order of magnitude. The Cd and Zn concentrations (order 10 -8 mole Cd/mole Ca and 10 -5 mole Zn/mole Ca) of species with low surface area show an increase with decreasing isotopic temperatures. This increase is consistent with the increasing concentrations of these metals from low values in surface waters to higher values at depth. The variance of Cd and Zn over the last 30,000 years in the central South Atlantic is consistent with the probable variability of the dissolved trace elements at the calcification levels of the species analyzed. Cu and Ba are irreproducible and probably sensitive to residual contaminant phases. The trace element content of the tests differs from levels observed in a recent coprecipitation study. Foraminifera may be a significant vector in zinc cycling in the ocean.

Boyle, Edward A.

1981-03-01

2

Metabolic crossroads of iron and copper  

PubMed Central

Interactions between the essential dietary metals, iron and copper, have been known for many years. This review highlights recent advances in iron-copper interactions with a focus on tissues and cell types important for regulating whole-body iron and copper homeostasis. Cells that mediate dietary assimilation (enterocytes) and storage and distribution (hepatocytes) of iron and copper are considered, along with the principal users (erythroid cells) and recyclers of red cell iron (reticuloendothelial macrophages). Interactions between iron and copper in the brain are also discussed. Many unanswered questions regarding the role of these metals and their interactions in health and disease emerge from this synopsis, highlighting extensive future research opportunities.

Collins, James F; Prohaska, Joseph R; Knutson, Mitchell D

2013-01-01

3

Synthesis and properties of barium titanate solid solution thin films deposited on copper substrates  

Microsoft Academic Search

Barium titanate thin films were deposited via chemical solution deposition using a hybrid-chelate chemistry directly on copper foil substrates. A process was developed to crystallize and densify the ferroelectric films at 900°C by using a reductive atmosphere containing nitrogen, hydrogen, water vapor, and oxygen impurities such that film constituents were oxidized to form barium titanate and the foil substrate remained

Jon Fredrick Ihlefeld

2006-01-01

4

Short-term effects of intratracheal installations of yttrium barium copper oxide.  

National Technical Information Service (NTIS)

Inhalation exposures to the new high-temperature ((Tc)) superconductor (SC) materials can occur during manufacturing and fabrication processes. In this exploratory study, we examined the pulmonary response to the deposition of an yttrium barium copper oxi...

J. E. London L. R. Newkirk B. E. Lehnert

1990-01-01

5

Absorbing properties and structural design of microwave absorbers based on carbonyl iron and barium ferrite  

NASA Astrophysics Data System (ADS)

Carbonyl iron and barium ferrite powder (BaZn 1.5Co 0.5Fe 16O 27) were prepared in this work. The complex permittivity and permeability spectra for rubber radar absorbing materials employing carbonyl iron and barium ferrite powders were measured. A database describing the frequency dependence of the permittivities and permeabilities of the carbonyl iron and barium ferrite microwave absorbers with various powder percentage compositions in 2-18 GHz was created. Based on the database, the single-layer and double-layer absorbers were designed and prepared, and their microwave absorption properties were investigated. The results indicate that the carbonyl iron powder prepared via thermal decomposition of iron pentacarbonyl is single cubic iron and of spherical shape. The barium ferrite powder is single W-type ferrite and a hexagonal flake. The absorption band of the double-layer microwave absorber is obviously more than that of the single-layer absorber. The double-layer microwave absorbers with reflection loss <-13 dB over the range of 6-18 GHz and reflection loss <-8 dB over the range of 2-18 GHz were prepared. The thicknesses of the absorbers are only 3.6 and 3.7 mm, respectively.

Feng, Y. B.; Qiu, T.; Shen, C. Y.

2007-11-01

6

Synthesis and properties of barium titanate solid solution thin films deposited on copper substrates  

NASA Astrophysics Data System (ADS)

Barium titanate thin films were deposited via chemical solution deposition using a hybrid-chelate chemistry directly on copper foil substrates. A process was developed to crystallize and densify the ferroelectric films at 900°C by using a reductive atmosphere containing nitrogen, hydrogen, water vapor, and oxygen impurities such that film constituents were oxidized to form barium titanate and the foil substrate remained metallic. The crystallized films are polycrystalline with equiaxed morphology and average grain diameters in excess of 100 mn. The dielectric properties exhibit permittivities in excess of 1800 at room temperature and zero bias with tunabilites of greater than 90% and high field loss tangents of less than 1%. The phase transition temperature and temperature coefficient of capacitance modified by partially substituting zirconium, hafnium, and tin for titanium. The resulting films were single phase and the phase transition shifts were consistent with bulk materials. A reduction in permittivity was observed for increasing substituent level and was attributed to a reduction in grain size for both barium titanate zirconate and barium titanate hafnate. Processing conditions were chosen to stabilize Sn2+ during the firing process in an attempt to flux the system and increase grain size. The barium titanate stannate films had less reduction in grain size per substituent level than either zirconium or hafnium, however a similar reduction in permittivity was observed. The diminished dielectric response was explained by a defect reaction involving divalent tin and oxygen vacancies that quenched the extrinsic domain response to the dielectric constant. Barium borate fluxes were used to improve densification and crystallinity. Barium borate additions between 0 and 3% uniformly increased grain size and density, while levels greater than 3% resulted in anomalous grain growth. Films with exaggerated grains show tetragonal peak splitting in the X-ray diffraction patterns, consistent with bulk barium titanate. In materials without exaggerated grain growth, dielectric measurements revealed permittivities in excess of 3000 at room temperature (for average grain sizes of approximately 160 nm). This value is equivalent to the finest-prepared bulk ceramics and substantially greater than any polycrystalline film ever reported. This has been attributed to in improvement in film crystallinity. These two accomplishments - tetragonal crystal symmetry and permittivities in excess of 3000 - represent dramatic breakthroughs in ferroelectric thin film technology. (Abstract shortened by UMI.)

Ihlefeld, Jon Fredrick

7

A rapid titrimetric determination of iron in copper concentrates and copper-bearing leach solutions.  

PubMed

A titrimetric method for the determination of iron(III) in the presence of copper is presented. This method involves the reduction of iron(III) with titanous sulphate followed by titration with dichromate. It has been successfully used for the determination of iron in both leach solutions and copper concentrates with a relative error of 1%. PMID:18962207

Sastri, V S

1978-01-01

8

Fabrication, characterization and microwave properties of polyurethane nanocomposites reinforced with iron oxide and barium titanate nanoparticles  

Microsoft Academic Search

Polyurethane (PU) nanocomposites reinforced with magnetic iron oxide nanoparticles and\\/or dielectric barium titanate nanoparticles fabricated by the surface-initiated-polymerization approach were investigated. The polymer matrix incorporated with different nanoparticles shows different presenting status surrounding the nanoparticles, i.e., chemical bonding, physical entanglement and bulk polymer chain. The nanoparticles have a different effect on the thermal stability of the polymer nanocomposites. By embedding

Z. Guo; S.-E. Lee; H. Kim; H. T. Hahn; A. B. Karki; D. P. Young

2009-01-01

9

Magnetic nanocomposites of mixed oxides of iron and barium synthesized under different oxidative environments  

Microsoft Academic Search

Synthesis of nanocomposites of mixed oxides of iron and barium in a copolymer matrix of aniline and formaldehyde using a chemical\\u000a route at room temperature is reported. X-ray diffraction, infrared, 57Fe Mossbauer studies, and scanning electron microscopy on as-synthesized samples, as well as samples obtained on heating at\\u000a different temperatures, are described. X-ray diffraction, 57Fe Mossbauer, and scanning electron microscopy

Shalima Gupta; Sajdha; H. N. Sheikh; B. L. Kalsotra; N. Kumar; S. Kumar

2008-01-01

10

Iron and copper release in drinking-water distribution systems.  

PubMed

A large-scale pilot study was carried out to evaluate the impacts of changes in water source and treatment process on iron and copper release in water distribution systems. Finished surface waters, groundwaters, and desalinated waters were produced with seven different treatment systems and supplied to 18 pipe distribution systems (PDSs). The major water treatment processes included lime softening, ferric sulfate coagulation, reverse osmosis, nanofiltration, and integrated membrane systems. PDSs were constructed from PVC, lined cast iron, unlined cast iron, and galvanized pipes. Copper pipe loops were set up for corrosion monitoring. Results showed that surface water after ferric sulfate coagulation had low alkalinity and high sulfates, and consequently caused the highest iron release. Finished groundwater treated by conventional method produced the lowest iron release but the highest copper release. The iron release of desalinated water was relatively high because of the water's high chloride level and low alkalinity. Both iron and copper release behaviors were influenced by temperature. PMID:17886579

Shi, Baoyou; Taylor, James S

2007-09-01

11

Copper and nickel partitioning in iron meteorites  

NASA Astrophysics Data System (ADS)

Trace element analyses using proton induced X-ray emission and synchrotron X-ray fluorescence have been made on metal and troilite from nine iron meteorites representing five geochemical groups. Nickel and copper distribution coefficients D (troilite/metal) vary by factors of 600 and 20, respectively, correlate positively with kamacite bandwidth and correlate negatively with bulk nickel content. Meteorites with bulk Ni of less than 10 percent have Cu-enriched troilite while those with Ni greater than 10 percent have Cu-depleted troilite. Since magmatic evolution and partial melting will produce Cu-enriched troilite only, the observation of Cu-depleted troilite in Ni-rich meteorites is evidence for subsolidus reequilibration, a process which reduces D(Cu) by transfer of Cu to exsolving metal. Elemental redistribution may have played an important role in establishing the present chemical trends in iron meteorites.

Sutton, S. R.; Delaney, J. S.; Smith, J. V.; Prinz, M.

1987-10-01

12

Yeast, a model organism for iron and copper metabolism studies  

Microsoft Academic Search

Virtually all organisms on earth depend on transition metals for survival. Iron and copper are particularly important because they participate in vital electron transfer reactions, and are thus cofactors of many metabolic enzymes. Their ability to transfer electrons also render them toxic when present in excess. Disturbances of iron and copper steady-state levels can have profound effects on cellular metabolism,

Jeane De Freitas; Henri Wintz; J Hyoun Kim; Helen Poynton; Tama Fox; Chris Vulpe

2003-01-01

13

Chemical synthesis of battery grade super-iron barium and potassium Fe(VI) ferrate compounds  

NASA Astrophysics Data System (ADS)

The chemical preparation of high purity potassium and barium ferrates for alkaline electrochemical storage are presented. The synthesized salts are used to demonstrate a variety of high capacity super-iron (Zn anode) alkaline AAA cell configurations which utilize these Fe(V) salts. Results of 500 days, full stability, of the synthesized K 2FeO 4 are presented. Synthetic pathways yielding 80-100 g of 96.5-99.5% pure K 2FeO 4 and BaFeO 4 are presented, and the products of these syntheses are demonstrated to provide a high energy electrochemical discharge in a variety of AAA alkaline cells. BaFeO 4 super-iron alkaline AAA cells provide over 0.8 W h during 2.8 ? discharge, yielding over 200% higher capacity than conventional alkaline batteries. The barium super-iron cell configurations studied provide higher capacity than the potassium super-iron alkaline cell configurations studied.

Licht, Stuart; Naschitz, Vera; Liu, Bing; Ghosh, Susanta; Halperin, Nadezhda; Halperin, Leonid; Rozen, Dmitri

14

Copper Stress Affects Iron Homeostasis by Destabilizing Iron-Sulfur Cluster Formation in Bacillus subtilis?  

PubMed Central

Copper and iron are essential elements for cellular growth. Although bacteria have to overcome limitations of these metals by affine and selective uptake, excessive amounts of both metals are toxic for the cells. Here we investigated the influences of copper stress on iron homeostasis in Bacillus subtilis, and we present evidence that copper excess leads to imbalances of intracellular iron metabolism by disturbing assembly of iron-sulfur cofactors. Connections between copper and iron homeostasis were initially observed in microarray studies showing upregulation of Fur-dependent genes under conditions of copper excess. This effect was found to be relieved in a csoR mutant showing constitutive copper efflux. In contrast, stronger Fur-dependent gene induction was found in a copper efflux-deficient copA mutant. A significant induction of the PerR regulon was not observed under copper stress, indicating that oxidative stress did not play a major role under these conditions. Intracellular iron and copper quantification revealed that the total iron content was stable during different states of copper excess or efflux and hence that global iron limitation did not account for copper-dependent Fur derepression. Strikingly, the microarray data for copper stress revealed a broad effect on the expression of genes coding for iron-sulfur cluster biogenesis (suf genes) and associated pathways such as cysteine biosynthesis and genes coding for iron-sulfur cluster proteins. Since these effects suggested an interaction of copper and iron-sulfur cluster maturation, a mutant with a conditional mutation of sufU, encoding the essential iron-sulfur scaffold protein in B. subtilis, was assayed for copper sensitivity, and its growth was found to be highly susceptible to copper stress. Further, different intracellular levels of SufU were found to influence the strength of Fur-dependent gene expression. By investigating the influence of copper on cluster-loaded SufU in vitro, Cu(I) was found to destabilize the scaffolded cluster at submicromolar concentrations. Thus, by interfering with iron-sulfur cluster formation, copper stress leads to enhanced expression of cluster scaffold and target proteins as well as iron and sulfur acquisition pathways, suggesting a possible feedback strategy to reestablish cluster biogenesis.

Chillappagari, Shashi; Seubert, Andreas; Trip, Hein; Kuipers, Oscar P.; Marahiel, Mohamed A.; Miethke, Marcus

2010-01-01

15

Tissue iron, copper and zinc levels in offspring of iron-sufficient and iron-deficient rats.  

PubMed

To study the effects of iron nutriture on tissue iron, copper and zinc contents, we fed iron-deficient or control diets to pregnant rats and their offspring. Pups were weaned to the same or opposite diet as that fed to their dams, yielding four groups: control-control (CC), control-deficient (CD), deficient-control (DC) and deficient-deficient (DD). Offspring were killed at 2, 21, 30, 60 and 90 days of age. Iron deficiency, induced by feeding a 5 ppm iron diet to the dam and/or to the weanlings, resulted in impaired body growth, lower hemoglobin and hematocrit levels and reduced iron levels in liver, spleen and kidney of the offspring. Two-day-old iron-deficient pups had hepatic copper levels 1.5- fold higher than control pups. By the end of the suckling period, hepatic copper levels in iron-deficient pups were 3-fold greater than those of control pups. Hepatic copper concentration in control-fed rats (CC and DC) declined with maturation. In deficient rats (CD and DD), this normal decrease in hepatic copper did not occur and in CD rats, there was a progressive accumulation of copper in the liver. Renal zinc concentrations were lower in CD and DD than in control-fed animals at 60 and 90 days of age. These interactions among iron, copper and zinc may assume clinical importance since iron deficiency is a common nutritional problem. PMID:7463170

Sherman, A R; Tissue, N T

1981-02-01

16

Parallels and contrasts between iron and copper metabolism.  

PubMed

This paper reviews the Second International Workshop on Iron and Copper Homeostasis, held in Pucón, Chile 10-13 November, 2001. We cover the presentations and papers published (this issue) with the intent to point out parallels, contrasts and cutting edge areas rather than to say something about every paper. Iron and copper metabolism have been intertwined for nearly 150 years and the interrelationship is growing with advances in understanding the role of ceruloplasmin as one example and the probable role of hephaestin as another. The transporter DMT1 (divalent metal transporter 1) clearly plays a major part in iron uptake and trafficking. Emerging evidence suggests that it plays a lesser role in manganese, cadmium and copper transport; but it is still being evaluated there. Yet another interaction may come from the IRE/IRP (Iron Responsive Element/Iron Regulatory Protein) story where a paradigmatic role in iron homeostasis is well established, but interaction with copper is only now emerging. Parallels include the nutrient status of both metals based on their utility for redox reactions as well as their toxicity primarily via reactive oxygen species. The workshop also revealed that alternate splicing of pre-mRNAs for iron and copper related proteins and tissue specific responses are additional similarities. Regulation of gene expression and excretion offered contrasts between the two metals. The workshop also considered a series of continuing and emerging issues. PMID:12572661

Garrick, Michael D; Núñez, Marco T; Olivares, Manuel; Harris, Edward D

2003-03-01

17

Effect of copper additions on the mechanical properties of iron  

NASA Astrophysics Data System (ADS)

The effect of copper alloying on the mechanical properties of iron is studied. Alloying of a model material (armco-iron) with 0.2-2.0% Cu is shown to increase the strength characteristics by a factor of 1.5-2.5 and to decrease the ductility by 8-60%.

Kostina, M. V.; Perkas, M. M.; Shelest, A. E.; Yusupov, V. S.

2011-05-01

18

Reduction of copper sulphate with elemental iron for preparation of copper nanoparticles  

NASA Astrophysics Data System (ADS)

Reduction of copper sulphate with elemental iron also known as cementation is a well known process used for the recovery of copper for a long time. In this study, the kinetics of the reaction of copper sulphate with iron wire and iron powder has been investigated. The reaction kinetics was studied as a function of different process parameters such as initial concentration, temperature and pH. In this research work, the effects of the above three parameters were studied for both types of iron substrates. It was found that with the iron wire the reaction obeys first order kinetics with respect to copper concentration whereas with the iron powder the order was found to be 1.5. The initial concentration was found to have considerable effect on the reaction kinetics of copper sulphate with elemental iron. The rate of reaction increases with an increase in the initial copper concentration up to a certain level and then decreases for the case of iron wire. However, for the reaction of copper sulphate with iron powder, the reaction rate decreases with an increase in the initial copper concentration. The effect of temperature on the reaction rate of copper sulphate for both types iron substrates (iron wire and iron powder) has also been studied in the temperature range of 23-54ºC. In both the cases, the reaction rate increases with an increase in temperature according to Arrhenius law. The activation energy for the reactions of copper sulphate with iron wire and iron powder was found to be 25.36 kJ/mol and 26.32 kJ/mol, respectively. The copper cementation reaction was found to be suitable to operate at a pH of 2.5-3 for iron wire and a pH of 3-4 for iron powder considering possible inhibition by copper hydroxyl complex formation at higher pH and the possible excess iron consumption by hydrogen reduction at lower pH. The copper particles were produced by the reduction of copper sulphate with elemental iron. The produced copper particles were obtained in the micro to nano range. Nowadays, nano sized particles has potential applications in different engineering and industrial fields. In this research work, emphasis was given to produce copper nano-particles. The reaction of copper sulphate solution with iron wire was studied in the presence of different organic solvents to verify the size and purity of the produced copper particles. 1-butanol proved to be a competent solvent in producing nearly nano sized copper particles with particles size as small as 165 nanometers in the form of clusters and purity as high as 93.67 weight% of copper. In order to determine the copper particles with the smallest size (nano range) and copper purity to a considerable level, characterization was done with the produced copper particles. For this purpose, the effect of sonication, addition of surfactant and chelation by adding EDTA were studied. It can be concluded that nano size copper particles with size less than 100 nm with copper purity of 100% were produced by reaction of 5% copper sulphate solution in the presence of 2 ml surfactant with iron wire and sonication. These copper nano particles have potential applications as catalysts for different industrial organic reactions. Finally, optimization studies of the process parameters effect on the reaction yield of copper sulphate with both types of iron substrates (wire and powder) were carried out using MATLAB 7.0 software. In this study, the relationship between three process variables namely the initial concentration of copper, temperature and pH of solution with reaction yield of copper cementation reaction was investigated for both the cases. Cubic mixture models were developed by using three levels full factorial design to find out the main effects and interactions of these process variables on the reaction yields of copper. The validity of the cubic mixture regressed models have been verified with high regression coefficients and through normal probability curves for residuals. Finally, response surface methodology was used to determine the optimum operating conditions of the cementation re

Nazim, Muhammad

19

Thermal properties of barium-borate glass containing iron in the temperature interval 300 to 700K  

Microsoft Academic Search

The study of thermophysical properties of glasses containing transition metal oxide has received lately more attention. Glasses containing iron oxide were studied by Avogadro et aI. [1 ], Kinser [2], Mackenzie [3] and others [41 . The major objective of this work is to study the effect of composition and temperature on the thermal properties of barium-borate glasses containing different

A. A. El-Sharkawy; A. M. Sanad; I. Kashif; M. I. Kenawy; M. B. Osman

1985-01-01

20

Synthesis and characterization of rare earth doped barium fluoride nanoparticles and derivatized copper phthalocyanine nanoparticles  

NASA Astrophysics Data System (ADS)

Nanoparticles of neodymium doped barium fluoride (Nd:BaFsb2) were synthesized for use as the inorganic component of an optical amplifier composite. Microemulsions were used to maintain domain size in the nano-regime (˜100 nm), and decreasing the volume fraction of the aqueous content, while simultaneously increasing the volume fraction of the cosurfactant (methanol), gave a linear relationship between decreasing domain size and increasing volume fraction of alcohol. As Nd was added to the BaFsb2 host, direct incorporation was observed at low dopant levels (0-10 mol-%), a two-phase mixture was observed at intermediate dopant levels (10-50 mol-%), and a nearly amorphous product resulted with very high Nd-dopant levels (>50 mol-%). Fluorescence measurements of the solids showed that concentration quenching was delayed until unusually high levels, probably as a result of the lost crystallinity. Praseodymium and ytterbium codoped barium fluoride (Pr,Yb:BaFsb2) were also synthesized in microemulsions. Though as-prepared powders did not fluoresce, treatment with high temperatures (900sp°C) and dynamic vacuum resulted in products which would fluoresce at 1.3 mum. Lower temperature treatments (500-750sp°C) were used to decrease sintering, however this resulted in Ybsp{3+} products in which Ybsp{3+} fluorescence was quenched by exposure to air. Contamination due to water and hydroxide is believed to be the reason. Ethanolic microemulsions were used to make copper phthalocyanine (CuPc), which was modified with either zinc phthalocyanine (ZnPc) or copper phthalcyaninesulfonic acid by means of a flow system. The sulfonic acid derivative was lost upon aqueous washing. The zinc derivatized product gave a dispersion in n-hexylamine, which was stable for seven days. The mole ratio of Cu:Zn was 1:1 for the solids dispersed in n-hexylamine, and was 6:1 for the solids that were not dispersed. Because underivatized CuPc formed by the same method did not result in a dispersed product, the dispersion mechanism is postulated to be due to interaction between the ZnPc on the surface and the n-hexylamine.

Bender, Christopher Mark

1998-12-01

21

Kinetics of iron–copper sulphides oxidation in relation to protohistoric copper smelting  

Microsoft Academic Search

This article deals with one specific step of the copper extractive metallurgy process: the roasting of iron–copper sulphides.\\u000a It aims at shedding light on an archaeological issue: the reconstruction of the copper extractive metallurgy processes during\\u000a protohistory (IVe–IIe millennium BC). Experimental simulations are performed at laboratory scale by modelizing the conditions of protohistoric\\u000a furnaces. Kinetic of roasting is studied by

Emilien BurgerDavid Bourgarit; David Bourgarit; Vincent Frotté; Fabien Pilon

2011-01-01

22

The effect of copper on iron reduction and its application to the determination of total iron content in iron and copper ores by potassium dichromate titration.  

PubMed

The International Standard Organization (ISO) specifies two titrimetric methods for the determination of total iron content in iron ores using potassium dichromate as titrant after reduction of the iron(III) by tin(II) chloride and/or titanium(III) chloride. These two ISO methods (ISO2597-1 and ISO2597-2) require nearly boiling-point temperature for iron(III) reduction and suffer from copper interference and/or mercury pollution. In this study, potassium borohydride was used for reduction of iron(III) catalyzed by copper ions at ambient temperatures. In the absence of copper, iron(III) reduction by potassium borohydride was sluggish while a trace amount of copper significantly accelerated the reduction and reduced potassium borohydride consumption. The catalytic mechanism of iron(III) reduction in sulfuric acid and hydrochloric acid was investigated. Potassium borohydride in sodium hydroxide solution was stable without a significant degradation within 24h at ambient conditions and the use of potassium borohydride prepared in sodium hydroxide solution was safe and convenient in routine applications. The applicability of potassium borohydride reduction for the determination of total iron content by potassium dichromate titration was demonstrated by comparing with the ISO standard method using iron and copper ore reference materials and iron ore samples. PMID:24840467

Hu, Hanjun; Tang, Yang; Ying, Haisong; Wang, Minghai; Wan, Pingyu; Jin Yang, X

2014-07-01

23

Calibration Equations for Energy-Dispersive XRF Determination of Copper, Iron and Lead in Copper Ore Slurries.  

National Technical Information Service (NTIS)

Calibration equations for the X-ray fluorescence analysis determination of copper, iron and lead in copper ore slurries have been derived and tested. The measurement of Ksub( alpha ) lines of copper and iron and Lsub( alpha ) line of lead excited by rays ...

M. Lakosz

1976-01-01

24

Copper Nqr and NMR Study of Metal-Substituted Yttrium BARIUM(2) COPPER(3) OXYGEN(7) and Yttrium BARIUM(2) COPPER(4) OXYGEN(8)  

NASA Astrophysics Data System (ADS)

Pulsed nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) have been used to investigate the effect of metal-substitution for copper in YBa_2Cu_3O_7 (YBCO123) and YBa_2Cu_4O_8 (YBCO124). Among many metal substitutions, Zn has an especially dramatic effect in suppressing the superconducting temperature T_{c}, and hence superconductivity. More interesting is that Zn and Fe have the same T_{c} suppression effect in YBCO124. This study focuses on the Zn substitutions in YBCO123 and Zn, Fe, and Co substitutions in YBCO124. In Zn doped YBCO123, Cu(2), plane site, NQR spectra and the frequency dependence of the spin-lattice relaxation rates have been measured over a temperature range from 77 K to 300 K to study the correlation of the suppression of the relaxation rate with the distance between the probe Cu nuclei and the impurity. It is found that the relaxation rate is insensitive to the variation of the NQR resonance frequency. However, by comparing the results of the Zn doped YBCO124 with those of YBCO123, it can be concluded that the suppression of the relaxation rate for both YBCO compounds in the normal state is caused by destruction of short-range antiferromagnetic correlation with substitution of nonmagnetic ion Zn on the Cu(2) sites. NQR and NMR measurements were carried out on both Cu(2), plane, and Cu(1), chain sites, for various concentrations of Zn, Fe, and Co dopants in YBCO124 over a temperature range from 77 K to 300 K. A strong correlation of the enhancement of Cu(2) spin lattice relaxation rate and suppression of superconductivity by impurities was found. The temperature dependence of the Cu(2) NMR linewidth exhibits a strong RKKY type exchange interaction below 225 K for Zn and Fe doped samples, which indicates the formation of the local magnetic moment. The enhancement of the relaxation rate is caused by the local magnetic moment Fe^ {+3} ion and the moments on Cu(2) neighbors when Zn^{+2} is substituted on Cu(2). This study gives us a clear picture of the spin pseudogap behavior in the high temperature superconductor cuprates. It also suggests that the magnetic moment on the CuO_2 plane may relate to the suppression of T_{c} in metal-substituted YBCO124.

Cheng, Show-Jye

25

Genotoxicity and mutagenicity of iron and copper in mice  

Microsoft Academic Search

The toxicity of trace metals is still incompletely understood. We have previously shown that a single oral dose of iron or\\u000a copper induces genotoxic effects in mice in vivo, as detected by single cell gel electrophoresis (comet assay). Here, we report\\u000a the effect of these metals on subchronic exposure. Mice were gavaged for six consecutive days with either water, 33.2 mg\\/kg\\u000a iron,

Daniel Prá; Silvia Isabel Rech Franke; Raquel Giulian; Maria Lúcia Yoneama; Johnny Ferraz Dias; Bernardo Erdtmann; João Antonio Pêgas Henriques

2008-01-01

26

Iron may play a role in pancreatic atrophy in copper deficiency  

SciTech Connect

The present study was undertaken to determine if pancreatic atrophy in copper deficient rats fed fructose is associated with excessive iron deposition. Weanling male and female rats were fed a copper deficient or copper adequate diet containing 62% carbohydrate as either fructose or starch. Another group of weanling rats consumed a copper deficient diet containing fructose that was low in iron. After consuming their respective diets for five weeks, the highest pancreatic iron concentration was seen in male rats consuming the copper deficient diet containing fructose. These animals also exhibited pancreatic atrophy. In contrast, neither copper deficient female rats fed fructose nor males fed starch exhibited pancreatic atrophy and their pancreata did not contain high levels of iron. In addition, reducing the availability of dietary iron in copper deficient rats fed fructose decreased pancreatic iron concentration and ameliorated the pathology. The data suggest that pancreatic atrophy in copper deficiency may be related to iron deposition in that tissue.

Fields, M.; Lewis, C.G.; Lure, M.D. (Georgetown Univ. Medical Center, Washington, DC (United States) Dept. of Agriculture, Beltsville, MD (United States) Univ. of Maryland, College Park (United States))

1991-03-15

27

Iron inhibits neurotoxicity induced by trace copper and biological reductants  

Microsoft Academic Search

The extracellular microenvironment of the brain contains numerous biological redox agents, including ascorbate, glutathione, cysteine and homocysteine. During ischemia\\/reperfusion, aging or neurological disease, extracellular levels of reductants can increase dramatically owing to dysregulated homeostasis. The extracellular concentrations of transition metals such as copper and iron are also substantially elevated during aging and in some neurodegenerative disorders. Increases in the extracellular

Anthony R. White; Kevin J. Barnham; Xudong Huang; Irene Voltakis; Konrad Beyreuther; Colin L. Masters; Robert A. Cherny; Ashley I. Bush; Roberto Cappai

2004-01-01

28

The transition metals copper and iron in neurodegenerative diseases  

Microsoft Academic Search

Neurodegenerative diseases constitute a worldwide health problem. Metals like iron and copper are essential for life, but they are also involved in several neurodegenerative mechanisms such as protein aggregation, free radical generation and oxidative stress. The role of Fe and Cu, their pathogenic mechanisms and possible therapeutic relevance are discussed regarding four of the most common neurodegenerative diseases, Alzheimer's, Parkinson's

Susana Rivera-Mancía; Iván Pérez-Neri; Camilo Ríos; Luis Tristán-López; Liliana Rivera-Espinosa; Sergio Montes

2010-01-01

29

a Josephson Junction Stack Model for Superconducting Yttrium Barium Copper Oxide Crystals  

NASA Astrophysics Data System (ADS)

High-T_{c} cuprate superconductivity is the central problem in condensed matter physics today. A critical issue is the symmetry of the superconducting wavefunction, which fundamentally links experiment and microscopic theory, and places important constraints on the pairing mechanism. The symmetry of the pair wavefunction is therefore a subject of intense theoretical and experimental investigation. In this thesis we present a Josephson Junction Stack model for superconducting Yttrium-Barium-Copper-Oxide (YBCO) crystals, and use it to analyse results of magnetically modulated resistance (MMR) experiments on these crystals, with a view to uncovering possible signatures of the order parameter symmetry. The YBCO crystal is modeled as a stack of Cu-O bilayers coupled to each other through the Josephson effect. Constituent planes of the bilayer are separated by 3.2 A, while neighboring bilayers are 8.2 A apart. Two levels of Josephson coupling arise: between planes of the bilayer, and between neighboring bilayers; they have different field and temperature scales. We derive the electrodynamics of the stack in the presence of an ab plane magnetic field and calculate the magnetically modulated resistance (MMR), when a c-axis current is passed through the crystal, using a resistively shunted junction (RSJ) framework. We show that in the limit of very small junction capacitance, applicable here, the MMR signal across the stack, proportional to the voltage across it, is obtained by scalar superposition of the voltages across the individual junctions. We show that different signatures emerge in the MMR spectra as a function of temperature and field, for order parameters which have a phase difference of pi between the planes of the bilayer, and those which do not. We show that the MMR spectra of YBCO are consistent with the hypothesis of an order parameter with a d-wave component. This thesis contains five chapters. Chapter One is the Introduction; in Chapter Two we discuss the Crystal Structure of YBCO. Chapter Three reviews the Symmetry of the Order Parameter. In Chapter Four we present the Josephson Stack Model of YBCO, and calculate the MMR Spectra. Chapter Five is the Conclusion.

Baindur, Satyen G.

30

Copper, iron and zinc in Alzheimer's disease senile plaques  

Microsoft Academic Search

Concentrations of copper (Cu), iron (Fe) and zinc (Zn) were measured in the rims and cores of senile plaques (SP) and in the neuropil of the amygdala of nine Alzheimer's disease (AD) patients and in the neuropil of the amygdala of five neurologically normal control subjects using micro particle-induced X-ray emission (micro-PIXE). Comparison of SP rim and core values revealed

M. A Lovell; J. D Robertson; W. J Teesdale; J. L Campbell; W. R Markesbery

1998-01-01

31

Distribution of iron, copper and manganese in the Arabian Sea  

NASA Astrophysics Data System (ADS)

The distribution of iron, copper and manganese was studied on a zonal transect of the Arabian Sea during the SW monsoon in 2007. The distribution of metals in the eastern and western ends of the transect are completely different, with concentrations of Fe and Mn higher in the east, but copper much higher in the west. Redox cycling in the east, and enhanced ventilation in the west contributes to these processes. It seems likely that blooms of Phaeocystis sp. contribute to the pronounced surface depletion and oxicline regeneration we observe, particularly for copper. The results are very different than similar surveys in the Peru upwelling, indicating controls by very different processes. These results have important implications for carbon and nitrogen cycling, particularly for processes mediated by key Cu and Fe metalloenzymes.

Moffett, James

2014-05-01

32

Seminar on Role of Copper and Copper Alloys in Iron and Steel Industry. Proceedings of the Seminar Held in Calcutta, August 18, 1978.  

National Technical Information Service (NTIS)

Various papers presented at the seminar covered the following topics: Use of Copper in Integrated Iron and Steel works; Copper Base Components in Iron & Steel Industries - Problems and Prospects in India; Steel Plant Requirements of High Conductivity Copp...

1978-01-01

33

Second harmonic generation of a copper vapor laser in barium borate  

Microsoft Academic Search

The beam from a Cu-vapor laser with an unstable resonator was focused in a nonlinear crystal, barium borate, for second-harmonic generation. Light at 255.3 nm was generated with a conversion efficiency of 8.9 percent at an average input power of 2.55 W. The characteristics of conversion were investigated.

K. Kuroda; T. Omatsu; T. Shimura; M. Chihara; I. Ogura

1990-01-01

34

Nuclear magnetic resonance of iron and copper disease states  

SciTech Connect

The tissue levels of paramagnetic ions are an important factor in the determination of T/sub 1/ values as observed by nuclear magnetic resonance (NMR) imaging. The increased levels of iron present in human disease states such as hemochromatosis lead to decreased T/sub 1/ values. The mean liver T/sub 1/ of three patients with iron storage disease was determined to be 130 msec, significantly different from the value of 154 msec, the mean for 14 normal controls. Whether NMR will be able to detect the increased copper levels in liver and brain in Wilson disease remains for further clinical trials to evaluate. NMR imaging, however, does serve as a noninvasive method for the diagnosis of states of iron overload and as a technique to follow progression of disease or response to medical therapy.

Runge, V.M. (Vanderbilt Univ., Nashville, TN); Clanton, J.A.; Smith, F.W.; Hutchison, J.; Mallard, J.; Partain, C.L.; James, A.E. Jr.

1983-11-01

35

Copper Deficiency in Sheep with High Liver Iron Accumulation  

PubMed Central

An outbreak of enzootic ataxia among sheep raised in the northeastern region of Brazil is described. Copper (Cu) deficiency was diagnosed in a herd of 56 sheep, among which five presented characteristic clinical symptoms of enzootic ataxia. The symptoms began 30 days after birth, with a clinical condition that included locomotion difficulty, limb ataxia, tremors, and continual falls. Liver biopsies were performed and blood was collected to determine hepatic and plasmatic Cu, iron (Fe), and zinc (Zn) concentration, respectively. The laboratory results showed that the animals presented low copper concentrations in the plasma and liver, without difference between the clinically healthy animals and those affected by enzootic ataxia. Even after supplementation with adequate Cu levels had been recommended, it was found on a new visit to the farm four months later that one animal still presented a clinical condition and that the hepatic Cu levels of the herd had not risen. Despite the low copper content of the diet, the high hepatic Fe levels found suggest that antagonism due to this element may have been an important factor in triggering copper deficiency in these animals, and thus, additional copper supplementation may be necessary for these animals.

de Sousa, Isadora Karolina Freitas; Hamad Minervino, Antonio Humberto; Sousa, Rejane dos Santos; Chaves, Dowglish Ferreira; Barros, Isabella de Oliveira; de Araujo, Carolina Akiko Sato Cabral; Junior, Raimundo Alves Barreto; Ortolani, Enrico Lippi

2012-01-01

36

Mild copper deficiency alters gene expression of proteins involved in iron metabolism  

Microsoft Academic Search

Iron and copper homeostasis share common proteins and are therefore closely linked to each other. For example, copper-containing proteins like ceruloplasmin and hephaestin oxidize Fe2+ during cellular export processes for transport in the circulation bound to transferrin. Indeed, copper deficiency provokes iron metabolism disorders leading to anemia and liver iron accumulation.The aim of the present work was to understand the

Sylvain Auclair; Christine Feillet-Coudray; Charles Coudray; Susanne Schneider; Martina U. Muckenthaler; Andrzej Mazur

2006-01-01

37

Promotion of atherogenesis by copper or iron-Which is more likely?  

SciTech Connect

Iron levels increase in atherosclerotic lesions in cholesterol fed-rabbits and play a role in atherosclerosis. We investigated whether copper also rises. Male New Zealand White rabbits were fed high-cholesterol diets for 8 weeks. After sacrifice, lesion sizes were determined, and elemental analyses of the lesion and unaffected artery wall performed using nuclear microscopy. Unlike iron, lesion copper is decreased by about half compared with the unaffected artery wall, and much less copper than iron is present. Our data suggest that iron may be more likely to play a role in the promotion of atherosclerosis than copper.

Rajendran, Reshmi [Centre for Ion Beam Applications, Department of Physics, National University of Singapore, MD7, 8 Medical Drive, Singapore 117597 (Singapore); Department of Biochemistry, National University of Singapore, MD7, 8 Medical Drive, Singapore 117597 (Singapore); Ren, Minqin [Centre for Ion Beam Applications, Department of Physics, National University of Singapore, MD7, 8 Medical Drive, Singapore 117597 (Singapore); Ning, Pan [Department of Biochemistry, National University of Singapore, MD7, 8 Medical Drive, Singapore 117597 (Singapore); Tan Kwong Huat, Benny [Department of Pharmacology, National University of Singapore, MD7, 8 Medical Drive, Singapore 117597 (Singapore); Halliwell, Barry [Department of Biochemistry, National University of Singapore, MD7, 8 Medical Drive, Singapore 117597 (Singapore)]. E-mail: bchbh@nus.edu.sg; Watt, Frank [Centre for Ion Beam Applications, Department of Physics, National University of Singapore, MD7, 8 Medical Drive, Singapore 117597 (Singapore)

2007-02-02

38

Raman Studies of Yttrium BARIUM(2) (COPPER(1-X) NICKEL(X)(3) OXYGEN(7-DELTA) and (yttrium BARIUM(2) COPPER(3) OXYGEN(7))(M)(PRASEODYMIUM BARIUM(2) COPPER(3) OXYGEN(7))(N) Superlattices  

NASA Astrophysics Data System (ADS)

Raman measurements on YBa_2(Cu _{1-x}Ni_{x})O_ {7-delta} and (YBa _2Cu_3O_7)_{m}(PrBa _2Cu_3O_7)_{n} superlattices have been performed. The unusual softening of the B_{1g} -like phonon of YBa_2Cu_3O _7 is studied as a function of T _{c} by substituting up to 6 atomic percent nickel for Cu. The abrupt onset and small temperature range over which the softening occurs in undoped YBa_2Cu_3O_7 are modified upon doping with the softening occurring well above T_{c} and continuing smoothly to 10K when T_{ c} is reduced to 71K. The phonon linewidth in the doped films shows no anomalies, regardless of Ni concentration. In contrast, the self-energies of the A_{g} modes associated with the plane copper (Cu(2)) and apical oxygen (O4) atoms reveal normal thermal behavior for all films. We conclude that an additional mechanism, besides strong coupling of phonons to superconducting electrons, contributes to the B_{1g} phonon anomalies in the Ni-doped samples. The Raman spectra from artificial structures of c- and a-axis oriented superlattices (YBa _2Cu_3O_7)_{m}(PrBa _2Cu_3O_7)_{n} with 1 < m, n < 15 are, in general, similar to those obtained from samples of the individual constituents. The observed Raman active vibrations of the superlattice are readily identified through comparison with spectra from the bulk components. The dependence of the phonon frequencies on m and n shows a significant softening of the vibration associated with the apical oxygen atom (O(4)) in PrBa_2Cu_3O _7 with reductions in the Pr-layer thickness (d_{Pr}). The modifications to the self energy of this phonon for both superlattice orientations only occur when d_{Pr} < 25A and therefore establish the primary importance of the Pr-layer thickness in affecting the observed softening. These phonon renormalizations are consistent with charge redistribution in the immediate vicinity (~10A) of the interface arising from the unequal Fermi energies associated with the alternating layers. The degree of inter-diffusion between Pr and Y sites is shown to be negligible with no detectable interfacial alloying. Reminiscent of behavior in bulk YBa_2Cu_3O _7, the out-of-phase O(2)-O(3) phonon confined to Y-layers as small as two unit cells softens below the superconducting transition temperature T_ {c}. The corresponding phonon localized to the Pr layers shows no softening down to n = 1 and therefore suggests the absence of proximity induced superconductivity in the rm PrBa_2Cu _3O_7 layers.

Ham, Kyungmin

39

Iron and copper homeostasis and intestinal absorption using the Caco2 cell model.  

PubMed

Whole body homeostasis can be viewed as the balance between absorption and excretion, which can be regulated independently. Present evidence suggests that for iron, intestinal absorption is the main site for homeostatic regulation, while for copper it is biliary excretion. There are connections between iron and copper in intestinal absorption and transport. The blue copper plasma protein, ceruloplasmin, and its intracellular homologue, hephaestin, play a role in cellular iron release. The studies reviewed here compare effects of Fe(II) and Cu(II) on their uptake and overall transport by monolayers of polarized Caco2 cells, which model intestinal mucosa. In the physiological range of concentrations, depletion of cellular iron or copper (by half) increased uptake of both metal ions. Depletion of iron or copper also enhanced overall transport of iron from the apical to the basal chamber. Copper depletion enhanced overall copper transport, but iron depletion did not. Pretreatment with excess copper also stimulated copper absorption. Plasma ceruloplasmin (added to the basal chamber) failed to enhance basolateral iron release, and Zn(II) failed to compete with Cu(II) for uptake. Neither copper nor iron deficiency altered expression of IREG1 or DMT1 (-IRE form) at the mRNA level. Thus, in the low-normal range of iron and copper availability, intestinal absorption of both metals appears to be positively related to the need for these elements by the whole organism. The two metal ions also influenced each other's transport; but with copper excess, other mechanisms come into play. PMID:12572674

Linder, Maria C; Zerounian, Nora R; Moriya, Mizue; Malpe, Rashmi

2003-03-01

40

Recovery of iron from copper slag by deep reduction and magnetic beneficiation  

NASA Astrophysics Data System (ADS)

Aiming at recovering iron from high-iron-content copper slag, this article introduced a combination technology of deep reduction and magnetic beneficiation, investigated the iron recovery efficiency and optimized the technical conditions. When coke powder with 86wt% fixed carbon was used as a reductant, iron was successfully extracted from the copper slag. Under the optimized condition of the coke powder content of 14wt%, the calcium-to-silicon mass ratio (Ca/Si) of 0.2, the roasting temperature of 1300°C, the roasting time of 3 h, the grinding time of 20 min, and the magnetic field intensity of 61 kA·m-1, the iron recovery rate of the copper slag can reach 91.82%, and the extracted iron powder has an iron grade of 96.21%. With the characteristics of high iron grade and low impurity content, the extracted iron powder can be used as high-quality raw materials of weathering steel.

Li, Ke-qing; Ping, Shuo; Wang, Hong-yu; Ni, Wen

2013-11-01

41

VAPOR PHASE MERCURY SORPTION BY ORGANIC-SULFIDE COATED BIMETALLIC IRON-COPPER NANOPARTICLE AGGREGATES  

EPA Science Inventory

Tetra sulfide silane coated iron-copper nano-particle aggregates are found to be potentially very high capacity sorbents for vapor phase mercury capture. High equilibrium capacities were obtained for the silane coated iron copper nano-aggregate sorbent at 70 oC and 120 oC. Even a...

42

A novel iron- and copper-binding protein in the Lyme disease spirochaete.  

PubMed

Iron and copper are transition metals that can be toxic to cells due to their abilities to react with peroxide to generate hydroxyl radical. Ferritins and metallothioneins are known to sequester intracellular iron and copper respectively. The Lyme disease pathogen Borrelia burgdorferi does not require iron, but its genome encodes a ferritin-like Dps (DNA-binding protein from starved bacteria) molecule, which has been shown to be important for the spirochaete's persistence in the tick and subsequent transmission to a new host. Here, we show that the carboxyl-terminal cysteine-rich (CCR) domain of this protein functions as a copper-binding metallothionein. This novel fusion between Dps and metallothionein is unique to and conserved in all Borrelia species. We term this molecule BicA for Borrelia iron- and copper-binding protein A. An isogenic mutant lacking BicA had significantly reduced levels of iron and copper and was more sensitive to iron and copper toxicity than its parental strain. Supplementation of the medium with iron or copper rendered the spirochaete more susceptible to peroxide killing. These data suggest that an important function of BicA is to detoxify excess iron and copper the spirochaete may encounter during its natural life cycle through a tick vector and a vertebrate host. PMID:23061404

Wang, Peng; Lutton, Anthony; Olesik, John; Vali, Hojatollah; Li, Xin

2012-12-01

43

Copper-Dependent Iron Assimilation Pathway in the Model Photosynthetic Eukaryote Chlamydomonas reinhardtii  

PubMed Central

The unicellular green alga Chlamydomonas reinhardtii is a valuable model for studying metal metabolism in a photosynthetic background. A search of the Chlamydomonas expressed sequence tag database led to the identification of several components that form a copper-dependent iron assimilation pathway related to the high-affinity iron uptake pathway defined originally for Saccharomyces cerevisiae. They include a multicopper ferroxidase (encoded by Fox1), an iron permease (encoded by Ftr1), a copper chaperone (encoded by Atx1), and a copper-transporting ATPase. A cDNA, Fer1, encoding ferritin for iron storage also was identified. Expression analysis demonstrated that Fox1 and Ftr1 were coordinately induced by iron deficiency, as were Atx1 and Fer1, although to lesser extents. In addition, Fox1 abundance was regulated at the posttranscriptional level by copper availability. Each component exhibited sequence relationship with its yeast, mammalian, or plant counterparts to various degrees; Atx1 of C. reinhardtii is also functionally related with respect to copper chaperone and antioxidant activities. Fox1 is most highly related to the mammalian homologues hephaestin and ceruloplasmin; its occurrence and pattern of expression in Chlamydomonas indicate, for the first time, a role for copper in iron assimilation in a photosynthetic species. Nevertheless, growth of C. reinhardtii under copper- and iron-limiting conditions showed that, unlike the situation in yeast and mammals, where copper deficiency results in a secondary iron deficiency, copper-deficient Chlamydomonas cells do not exhibit symptoms of iron deficiency. We propose the existence of a copper-independent iron assimilation pathway in this organism.

La Fontaine, Sharon; Quinn, Jeanette M.; Nakamoto, Stacie S.; Page, M. Dudley; Gohre, Vera; Moseley, Jeffrey L.; Kropat, Janette; Merchant, Sabeeha

2002-01-01

44

Experimental study of methanol synthesis catalysts containing copper plated iron fibers  

Microsoft Academic Search

An experimental study was conducted which evaluated the performance of methanol synthesis catalysts containing copper plated, polycrystalline iron fibers. The active catalyst material was comprised of Cu\\/ZnO\\/AlâOâ with atomic ratio, Cu\\/Zn\\/Al = 6\\/3\\/1. It was necessary to copper plate the iron fibers since iron catalyzes the more thermodynamically favorable synthesis of methane from CO, COâ, and Hâ. A deposition by

Bieser; A. L. Jr

1983-01-01

45

Phase characterization of dysprosium barium copper oxide thin films grown on strontium titanate by molecular beam epitaxy  

SciTech Connect

X-ray diffraction, transmission electron microscopy, and /ital in/ /ital situ/ reflection high energy electron diffraction studies of thin epitaxial dysprosium barium copper oxide films grown by oxygen plasma molecular beam epitaxy (MBE) on strontium titanate substrates are presented. A remarkable variety of structure is revealed, making clear both the possibilities and challenges for this growth technique as applied to the cuprate superconductors. The films studied are highly epitaxial, obtained through the use of shuttered molecular beams to encourage the layered structure characteristic of superconducting DyBa/sub 2/Cu/sub 3/O/sub 7/minus//ital x// (''123''). While some of these films are superconducting as deposited, more often they are semiconducting or insulating. The 123-like material in these films has a lengthened c-axis, perhaps due to nonstoichiometry. Phases related to DyBa/sub 3/Cu/sub 2/O/sub /ital x// (the other perovskite) are also very important for epitaxial growth, and display a distinctive signature in the RHEED patterns. Other epitaxial impurity phases including BaCuO/sub 2/ and a new orthorhombic phase are also characterized.

Hellman, E. S.; Schlom, D. G.; Marshall, A. F.; Streiffer, S. K.; Harris, J. S., Jr.; Beasley, M. R.; Bravman, J. C.; Geballe, T. H.; Eckstein, J. N.; Webb, C.; and others

1989-05-01

46

Microstructure and electrical properties of Mn-doped barium strontium titanate thin films prepared on copper foils  

NASA Astrophysics Data System (ADS)

Ba 0.7- xSr 0.3Mn xTiO 3 ( x = 0, 0.025, 0.05) thin films have been prepared on copper foils using sol-gel method. The films were processed in an atmosphere with low oxygen pressure so that the substrate oxidation is avoided and the formation of the perovskite phase is allowed. XRD and SEM results showed that Mn doping enhanced the crystallization of the perovskite phase in the films. The Mn substitution prevents the reduction of Ti 4+ to Ti 3+, which is supported by XPS analysis. The Ba 0.7- xSr 0.3Mn xTiO 3 film with x = 0.025 (BSMT25) exhibits preferred dielectric behavior and a lower leakage current density among the three thin films. The dielectric constant and loss of the BSMT25 film are 1213.5 and 0.065 at 1 MHz and around zero field, which are mostly desired for embedded capacitor applications. The mechanism of Mn doping on improving the electrical properties of barium strontium titanate (BST) thin films was investigated.

Fan, Yanhua; Yu, Shuhui; Sun, Rong; Li, Lei; Yin, Yansheng; Wong, Ka-Wai; Du, Ruxu

2010-09-01

47

Decomposition of the sulfates of copper, iron (II), iron (III), nickel, and zinc: XPS, SEM, DRIFTS, XRD, and TGA study  

Microsoft Academic Search

The bulk and surface characteristics during decomposition of the transition metal sulfates of copper, iron (II), iron (III), nickel, and zinc are investigated utilizing various spectroscopic techniques. An oxidized form of sulfur was detected on the surface during decomposition of all metal sulfate samples, except zinc sulfate. Surface characteristics were not necessarily representative of the bulk characteristics. Oxy-sulfate was observed

Ranjani V Siriwardane; James A Poston Jr; Edward P Fisher; Ming-Shing Shen; Angela L Miltz

1999-01-01

48

Removal of copper from carbon-saturated steel with an aluminum sulfide/iron sulfide slag  

SciTech Connect

Scrap iron and steel has long been considered a resource in the steel-making industry, and its value is largely determined by its impurity content. As the mini-mills, the major consumers of scrap iron and steel, expand into producing flat-rolled sheet, the demand for high-quality scrap will increase. Of the impurities present in scrap, copper is particularly troublesome because of its role in causing hot shortness. Therefore, the copper content of scrap should be kept below {approx} 0.1 wt%. A method for removing copper from steel could be used to improve the quality of scrap and make it more available for use by mini-mills. To determine the effectiveness of a binary slag consisting of aluminum sulfide and iron sulfide on the removal of copper from steel and iron, the distribution coefficient of copper between the slag and a carbon-saturated iron melt was investigated at 1,365 C. The composition of the slag was varied from nearly pure aluminum sulfide to pure iron sulfide. A maximum distribution coefficient of 30 was found, and the copper level in the iron melt was reduced to as low as 0.07 wt.% with a 4:1 ratio of iron to slag.

Cohen, A.; Blander, M.

1995-12-01

49

Removal of copper from aqueous solution using iron-containing adsorbents derived from methane fermentation sludge.  

PubMed

Iron-containing adsorbents prepared from methane fermentation sludge (MFS) were characterized by N(2) adsorption, XRD, SEM, EDX, pH determination and elemental analysis. The experiments for copper removal from aqueous solution using the MFS-derived adsorbents were performed, and the effects of iron content, forms of the iron (hydr)oxides, surface basicity and pH of the aqueous solution on copper removal were elucidated respectively. The desorption studies were also performed and the mechanism of Cu(II) adsorption was proposed. The results indicated that the adsorbent obtained at 700 degrees C for 1h in a steam atmosphere possessed the highest capability for Cu(II) adsorption. The high copper removal ability of the MFS-derived materials is attributed to their intermediate surface area, strong surface basicity and the presence of iron (hydr)oxides on their surface. The Cu(II) adsorption onto the composite adsorbents is via ion-exchange with H, Ca and K ions, surface precipitation and binding with active sites on the surface of iron (hydr)oxides at various pH values. The desorption of copper in deionized water is quite low. The irreversibility of copper adsorption on the iron-containing adsorbents is attributed to the formation of strong bonds between Cu(II) and the iron (hydr)oxides. The adsorbent can be applied to remove copper from water or soil by fixation onto the surface. PMID:19726131

Qian, Qingrong; Mochidzuki, Kazuhiro; Fujii, Takao; Sakoda, Akiyoshi

2009-12-30

50

Magnetic and magnetorheological properties of flowable compositions based on barium and strontium ferrites and iron oxides  

NASA Astrophysics Data System (ADS)

Magnetic and magnetorheological properties of a number of compositions are examined. The compositions are based on barium and strontium ferrites, magnetite, and (gamma) -Fe2O3, both commercial and synthesized using specially developed methods, suspended in transformer oil and synthetic binders based on phenol-formaldehyde, epoxyacrylic and pentaphthalic resins. The influence of numerous factors, such as the type and magnetic properties of the filler, types of the binder, magnetic properties of the composition on the orientational effect of the filler in a magnetic field was evaluated. The latter was judged by a magnitude of magnetorheological effect.

Lazareva, Tatjana G.; Shitik, Ilia G.

1997-02-01

51

Analysis of Yttrium-Barium-Copper-Oxide by x ray diffraction and mechanical characterization  

NASA Technical Reports Server (NTRS)

The efforts in developing high-temperature superconductor (HTSC) YBa2Cu3O7 electrical leads are to benefit future NASA missions that will carry payloads with sensitive instruments operating at cryogenic temperatures. Present-day leads made of copper or magnesium are responsible for as much as 50 percent of the parasitic heat load on cryogenic systems. A reduction of this load could be achieved by replacing the conventional materials with HTSC ceramic electrical leads. Superconductor quality has become a concern in the industry, as has the development of effective evaluation methods. The factors that need to be examined for these materials include material purity, mechanical properties, and superconducting ability below the critical temperature. We applied several methods to study these factors: thermogravimetric analysis, x-ray diffraction, tensile testing, and laser-generated ultrasound. Our objectives were to determine the average tensile strength and Young's modulus of the HTSC material and to compare them to those values for copper and manganin.

Arsenovic, Petar

1992-01-01

52

Serum iron, copper and zinc status in maternal and cord blood.  

PubMed

Pregnancy is associated with increased demand of all the nutrients like Iron, Copper, Zinc etc. and deficiency of any of these could affect pregnancy, delivery and out come of pregnancy. With this consideration, the study was conducted on 80 mothers and newborns and 20 age matched control women. Out of 80 mothers, 34 had Iron deficiency anemia and their Hb levels were below 9.0 gm/d(1). Pregnant women had significantly lower Iron and Zinc levels while Copper and Total Iron Binding Capacity (TIBC) were significantly higher (P<0.001). Newborns had significantly elevated Iron and Zinc levels and low levels of Copper and TIBC as compared to their mothers irrespective of Iron deficiency anemia. Micronutrient status of newborn was found to be dependent on their mother's micronutrient status. Besides, results also suggest micronutrient interactions, which are reflected in Iron/Zinc, Iron/Copper and Zinc/Copper ratios. In view of this, there is need for proper, adequate and balanced micronutrient supplementation during pregnancy to affect a healthy outcome. PMID:23105456

Upadhyaya, Chitra; Mishra, Sandhya; Ajmera, Peeyush; Sharma, Praveen

2004-07-01

53

VAPOR PHASE MERCURY SORPTION BY ORGANIC SULFIDE MODIFIED BIMETALLIC IRON-COPPER NANOPARTICLE AGGREGATES  

EPA Science Inventory

Novel organic sulfide modified bimetallic iron-copper nanoparticle aggregate sorbent materials have been synthesized for removing elemental mercury from vapor streams at elevated temperatures (120-140 °C). Silane based (disulfide silane and tetrasulfide silane) and alkyl sulfide ...

54

Liver and kidney concentrations of strontium, barium, cadmium, copper, zinc, manganese, chromium, antimony, selenium and lead in cats  

PubMed Central

Background In order to provide new knowledge on the storage of strontium (Sr), barium (Ba), cadmium (Cd), copper (Cu), zinc (Zn), manganese (Mn), chromium (Cr), antimony (Sb), selenium (Se) and lead (Pb) in the feline organism, we measured the concentrations of these elements in the liver, renal cortex and renal medulla, evaluating also the impact of age, sex or the occurrence of a chronic kidney disease (CKD). The element concentrations in the tissues of 47 cats (22 male; 25 female; aged between 2 months and 18 years) were measured using inductively coupled plasma mass spectrometry. Results Cu, Zn and Mn were the highest in the liver, followed by the renal cortex and the renal medulla. The Cd concentrations were lower in the renal medulla compared to the renal cortex and the liver, and Sr was higher in the renal medulla compared to the liver. The Se concentrations in the cortex of the kidneys were higher than in the medulla of the kidneys and in the liver. Higher Cd concentrations were measured in the renal cortex of female cats, while no further gender-related differences were observed. Except for Cr, Sb and Se, age-dependencies were detected for the storage of all elements. The occurrence of a CKD also affected the storage of the elements, with lower concentrations of Ba (renal medulla), Zn (renal cortex; renal medulla) and Mn (liver; renal medulla), but higher Cd concentrations (liver; renal cortex) in diseased cats. Conclusions In conclusion, the present results provide new information on the accumulation of specific elements in the feline liver and kidneys, demonstrating a dependency on age and an impaired kidney function, but not on the sex of the animals.

2014-01-01

55

Synthesis and thermal decomposition of freeze-dried copper–iron formates  

Microsoft Academic Search

The thermal decomposition of freeze-dried formate precursors for copper–iron oxides was investigated by means of DTA, TG, mass spectroscopy and X-ray powder diffractometry. The freeze-dried copper formate is crystalline. Its decomposition at about 200°C releases formic acid (HCOOH) and carbon dioxide (CO2) as main primary gaseous decomposition products beside metallic copper as a solid product. However, the decomposition of the

F. Kenfack; H. Langbein

2005-01-01

56

Magnetic Studies of Solid Solutions II. The Properties of Quenched Copper-Iron Alloys  

Microsoft Academic Search

The alloys of copper and iron which have been studied show unusual magnetic properties both in the saturation effects at low temperatures and in the apparent change in the magnetic moment of the dissolved iron atoms over the range of temperatures from 14°K to 1300°K. Further research is required on other alloy systems containing transition elements dissolved in the noble

F. Bitter; A. R. Kaufmann; C. Starr; S. T. Pan

1941-01-01

57

Kinetics of solution of hydrogen in liquid iron, nickel, and copper containing dissolved oxygen and sulfur  

Microsoft Academic Search

An investigation of the effect of surface active oxygen and sulfur on the rate of hydrogen solution in inductively stirred liquid iron, nickel, and copper was made using a modified constant-volume Sieverts' method. The overall and initial rates of hydrogen solution in liquid iron and nickel were found to decrease with increasing oxygen content in concentration ranges found in the

W. M. Small; R. H. Radzilowski; R. D. Pehlke

1973-01-01

58

Iron and copper as virulence modulators in human fungal pathogens.  

PubMed

Fungal pathogens have evolved sophisticated machinery to precisely balance the fine line between acquiring essential metals and defending against metal toxicity. Iron and copper are essential metals for many processes in both fungal pathogens and their mammalian hosts, but reduce viability when present in excess. However, during infection, the host uses these two metals differently. Fe has a long-standing history of influencing virulence in pathogenic fungi, mostly in regards to Fe acquisition. Numerous studies demonstrate the requirement of the Fe acquisition pathway of Candida, Cryptococcus and Aspergillus for successful systemic infection. Fe is not free in the host, but is associated with Fe-binding proteins, leading fungi to develop mechanisms to interact with and to acquire Fe from these Fe-bound proteins. Cu is also essential for cell growth and development. Essential Cu-binding proteins include Fe transporters, superoxide dismutase (SOD) and cytochrome c oxidase. Although Cu acquisition plays critical roles in fungal survival in the host, recent work has revealed that Cu detoxification is extremely important. Here, we review fungal responses to altered metal conditions presented by the host, contrast the roles of Fe and Cu during infection, and outline the critical roles of fungal metal homeostasis machinery at the host-pathogen axis. PMID:24851950

Ding, Chen; Festa, Richard A; Sun, Tian-Shu; Wang, Zhan-You

2014-07-01

59

Iron, Manganese and Copper Release from Synthetic Hydroxyapatite  

NASA Technical Reports Server (NTRS)

Kinetic stir-flow dissolution experiments were performed on iron- (Fe-SHA), manganese- (Mn-SHA), and copper- (Cu-SHA) containing synthetic hydroxyapatites. Solution treatments consisted of de-ionized water, citric acid and DTPA. Initially, Mn concentrations were higher than Cu concentrations and Fe concentrations were the lowest in all treatments. At later times Mn and Cu concentrations dropped in the DTPA treatment while Fe rose to the concentration similar to Mn and Cu. At all times, metal release concentrations in the water and citric acid treatments followed the trend of Mn>Cu>Fe. Rietveld analysis of x-ray diffraction data and ^31P NMR indicated that the metals substituted for Ca in the SHA structure. However, EPR data suggested that a metal (hydr)oxide phase existed either on the SHA surface or between the SHA crystallites. The metal concentration trend of Mn>Cu>Fe suggested that the initial solution metal concentrations are dependent on the dissolution of (hydr)oxides from SHA surfaces or between SHA crystallites. Similar metal concentrations at later times in the DTPA experiments suggests that metal concentrations were controlled by the release of Mn, Cu, or Fe from the SHA structure.

Sutter, B.; Hossner, L. R.; Ming, Douglas W.

1999-01-01

60

Use of Cement Copper in an Iron-Copper-Carbon Powder Metallurgy Alloy.  

National Technical Information Service (NTIS)

An investigation was made of the substitution of cement copper powder for commercial copper powder in an Fe-7 pct Cu-1 pct C powder metallurgy alloy. Copper powders from six different commercial cementation operations were separately upgraded by screening...

R. L. Crosby D. H. Desy R. M. Doerr

1970-01-01

61

Yttrium Barium Copper Oxide Superconducting Powder Generation by AN Aerosol Process  

NASA Astrophysics Data System (ADS)

Superconducting YBa_2Cu _3O_{7-delta } (YBCO) powders have been successfully generated by aerosol processes. Two effects of processing parameters on final superconducting powder characteristics were investigated. The aerosol YBCO powders have been characterized according to their oxygen stoichiometry, particle size distribution, morphology, magnetization, transition temperature and lattice cell dimensions. These properties were examined using thermogravimetric analysis (TGA), X-ray diffracton, aerosol instruments and a magnetometer. A series of aerosol YBCO powder sintering experiments including oxygen loading and desorption have been performed. Several quantitative relationships have been determined from the results of X-ray diffraction, TGA and magnetization measurements. Magnetization and Mossbauer spectrometry of the aerosol YBa_2(Cu_ {1-x}Fe_{rm x})_3O_ {7-delta} powders were conducted. The iron doping of aerosol YBCO powders led to a random replacement of Cu for Fe in the chain and planes of the host structure. A cascade impactor was used to classify the YBCO powders into different size regimes. Two length scales (penetration depth, lambda, and coherence length, xi) characterizing superconductivity in aerosol YBCO powders are established for the first time from magnetization measurements.

Zhou, Derong

62

Influence of indigenous and added iron on copper extraction from soil.  

PubMed

Experimental tests of copper leaching from a low permeability soil are presented and discussed. The objective of the experiments was to investigate the influence of indigenous and added iron in the soil towards copper mobilization. Metals' leaching was performed by flushing (column tests) or washing (batch tests) the soil with an aqueous solution of ethylenediaminetetraacetic acid, EDTA. An excess of EDTA was used in flushing tests (up to a EDTA:Cu molar ratio of about 26.2:1), while, in washing tests, the investigated EDTA vs. copper molar ratios were in the range between 1 (equimolar tests) and 8. Copper extraction yield in flushing tests (up to about 85%) was found to depend upon contact time between the soil and the leaching solution and the characteristics of the conditioning solution. The saturation of the soil with a NaNO(3) solution before the treatment, favoured the flushing process reducing the time of percolation, but resulted in a lower metal extraction during the following percolation of EDTA. The indigenous iron was competitive with copper to form EDTA complexes only when it was present in the organic and oxides-hydroxides fractions. Artificial iron addition to the soil resulted in an increase of both the exchangeable iron and the iron bonded to the organic fraction of the soil, thus increasing the overall amount of iron available to extraction. In both batch and continuous tests, the mechanism of copper extraction was found to involve the former dissolution of metal salts, that lead to an initial high concentration of both copper and selected competitive cations (essentially Ca(2+)), and the following EDTA exchange reaction between calcium and copper complexes. The initial metal salts dissolution was found to be pH-dependant. PMID:19477586

Di Palma, Luca

2009-10-15

63

Cadmium, mercury, iron, copper, manganese and zinc in the liver and kidney of the Icelandic lamb.  

PubMed

The purpose of this study was to evaluate the levels of cadmium, mercury, iron, copper, manganese and zinc in lamb liver and kidney from six areas in Iceland and to compare the results against aerial deposition data for the same elements obtained using moss as an indicator organism. The total number of samples was 96 for each organ. Cadmium was determined by graphite furnace atomic absorption spectrophotometry, mercury by cold-vapour atomic absorption, and iron, copper, manganese and zinc by inductively coupled plasma atomic emission spectrophotometry. Analysis of variance determined significance differences among means for areas, and Pearson's correlation coeffcients were calculated to study correlation among trace elements in liver and kidney. The mean fresh weight concentrations in lamb liver and kidney respectively were 0.045 and 0.058 mgkg(-1) for cadmium, 0.009 and 0.012 mgkg(-1) for mercury, 141 and 52.7 mgkg(-1) for iron, 28.1 and 2.89 mgkg(-1) for copper, 4.01 and 1.13 mgkg(-1) for manganese and 48.7 and 25.2 mgkg(-1) for zinc. Concentrations of cadmium, mercury and copper in the liver and kidney of the Icelandic lamb were low compared with data from other countries. Iron concentrations in the organs, however, were high. No sample exceeded 46% of the proposed maximum level for cadmium in organs for human consumption in the EC. Cadmium, mercury, iron and copper in the liver and kidney differed significantly between areas. Deposition of cadmium and copper in moss was not a usefull indicator in the evaluation of the susceptibility of the Icelandic lamb to accumulation of cadmium and copper. However, iron levels in Icelandic lamb liver showed the same pattern as results for iron from the moss study. The cadmium and mercury levels of organs from lambs grazing in the vicinity of Mount Hekla a few months after its eruption did not indicate a significant contamination from volcanic activity. PMID:11665737

Reykdal, O; Thorlacius, A

2001-11-01

64

Novel lead-free piezoelectric ceramics in the solid solution (1-x) bismuth iron oxide-barium titanate  

NASA Astrophysics Data System (ADS)

Piezoelectric materials are widely used in many areas of science and technology due to their electromechanical properties. The transformation of mechanical energy into electrical signals and vice versa based on the piezoelectric effect has led to the development of sensor devices and piezoelectric actuators used in accelerometers, pressure and vibration meters, micropositioning devices, ultrasound generators, motors etc. The most technologically important piezoelectric material is lead zirconate titanate PbZrO3-PbTiO3 (PZT), however, the commercial manufacture and application of PZT as a lead-based material represent serious health hazards. The need to reduce environmental contamination by lead-based substances has created the current drive to develop alternative lead-free piezoelectric materials. The present work describes a detailed investigation of the novel multifunctional ceramic material in a solid solution of bismuth iron oxide and barium titanate (1-x)BiFeO 3-xBaTiO3 (BFBT) with an emphasis on the room temperature piezoelectric properties and structural study. BFBT ceramics were prepared via the metal oxide solid-state preparation route. Addition of manganese oxide MnO2 increased the DC resistance by one to five orders of magnitude allowing high-field poling and piezoelectric strain measurements in Mn-modified BFBT ceramics. Piezoelectric d33 coefficients of 116 pC/N (low-field, Berlincourt) and 326 pC/N (effective, high-field) are reported for the compositions with x=0.25 and 0.33 respectively. Piezoelectric measurements using the Rayleigh law under applied large DC electric field indicated an increased low-field piezoelectric d33 coefficient to 150 pC/N (x=0.33). The DC bias is believed to stabilize the ferroclectric domain structure leading to stronger intrinsic and extrinsic contributions to the piezoelectric response in BFBT. Bright field TEM imaging confirmed formation of macroscopic domains following high field poling from initially frustrated domain state indicating the ability to induce long-range polarization order in BFBT ceramics. It is believed that the results of this work will contribute to the development of a family of lead-free piezoelectric materials based on BiFeO3-BaTiO3 system. KEYWORDS: Bismuth ferrite, Barium titanate, Lead-free, Piezoelectric ceramics, Crystal Structure

Leontsev, Serhiy

65

Effect of zinc supplementation on the antioxidant, copper, and iron status of physically active adolescents.  

PubMed

Puberty associated with intense physical activity results in oxidation stress. Zinc supplementation may benefit antioxidant capacity although it may also affect iron and copper status. This study evaluated the effect of zinc supplementation on antioxidant, zinc and copper status of physically active male football players (13 years +/- 0.4 years), divided in two groups and studied during 12 weeks: Zn-supplemented (Zn-SUP, 22 mg Zn d(-1) as zinc gluconate, n = 21) and placebo (PLA, n = 26). At baseline, there was no significant difference in biochemical indices between the two groups. After treatment, plasma zinc and erythrocyte iron increased in both groups (p < 0.001); urinary zinc increased (p < 0.001) only in Zn-SUP, and erythrocyte zinc decreased (p = 0.002) only in PLA. Plasma iron and copper decreased (p = 0.01 and p = 0.015, respectively) only in Zn-SUP. Plasma ferric-reducing ability and plasma conjugated dienes increased, and erythrocyte osmotic fragility decrease in both groups, although the latter two were significantly lower in Zn-SUP compared to PLA (p < 0.01). In conclusion, our study indicates that the use of 22 mg d(-1) of supplemental zinc during 12 week in adolescent athletes did not affect growth, improved markers of antioxidant status but reduced plasma iron and copper. Therefore, it appears that the use of zinc supplementation by healthy adolescent athletes benefits their antioxidant capacity but impairs copper and iron nutritional status. PMID:19277992

de Oliveira, Karla de Jesus Fernandes; Donangelo, Carmen Marino; de Oliveira, Astrogildo Vianna; da Silveira, Carmen Lucia Porto; Koury, Josely Correa

2009-04-01

66

Growth of highly oriented TlBaâCaâCuâO{sub 9-y} superconducting films on Ag substrates using a dip-coated barium calcium copper oxide sol-gel precursor  

Microsoft Academic Search

Thin films of baâCaâCuâOâ, a precursor of TlBaâCaâCuâO{sub 9-y}, were prepared by sol-gel synthesis from an all-alkoxide solution. The barium and calcium precursors were the respective metals reacted with 2-methoxyethanol, and the copper precursor was copper methoxide complexed by triethanolamine. Silver substrates were coated using the sol-gel solution by dip-coating. Subsequent processing included a low-temperature drying step (600 C), repeated

M. Paranthaman; D. B. Beach

1995-01-01

67

Morphology evolution of zinc-iron binary alloys electrodeposited with copper additive  

SciTech Connect

Zinc-iron electrodeposits have widely been adopted for surface treatment of automobile body steel sheet for corrosion resistance. Copper additive enhances dendrite formation of hexagonal columnar crystals of the zinc-iron electrodeposit. With 100 ppm of copper, these crystals show fine steps on (10 {center_dot} 0){eta} surfaces. With 150 ppm, the copper enhances nucleation on one of an apex on (00{center_dot}1){eta} of these crystals. With 300 ppm, the nucleation increases and fine platelet crystals precipitate preferentially at this apex. With further increase of copper to 1,000 ppm, the deposit becomes dendrite crystals and this apex becomes the growing tip of the dendrite.

Kondo, Kazuo; Murakami, Tomoya; Shinohara, Kunio [Univ. of Hokkaido, Sapporo (Japan)

1996-04-01

68

Chronic administration of iron and copper potentiates adipogenic effect of high fat diet in Wistar rats.  

PubMed

The primary objective of this research project is explore a possible adipogenic effect of iron and/or copper in albino Wistar rats kept on standard (STD) and high-fat (HFD) diets. The female Wistar rats in the study were divided into eight experimental groups (n = 6). Rats maintained on STD and HFD received 3 mg/l FeSO??7H?O, 4.88 mg/l CuSO? and a combination of 1.5 mg/l FeSO??7H?O and 2.44 mg/l CuSO? with drinking water. Control groups were kept on STD and HFD and received pure water without metal salts. Consumption of iron and copper in the groups of rats maintained on an STD did not produce a significant increase in weight, adipose tissue content or body mass index. However, the adipocyte size and infiltration were increased in the adipose tissue of STD-fed rats receiving a mixture of iron and copper with drinking water. The rats fed iron and copper and, especially, their combination on a HFD background had a significantly higher weight gain, adipose tissue content, morphometric parameters values and adipocyte size compared to STD- and HFD-fed controls. Iron and copper consumption produced their accumulation in the rats' adipose tissue. Moreover, the studied metals reduced adipose tissue concentration of chromium and vanadium. The lipoprotein profile and serum oxidative stress biomarkers were affected in the rats receiving the metals and STD. Hyperglycemia was observed in the rats receiving the studied metals on HFD-background. Based on the analysis of the test subjects, the study suggests that iron and copper administration, especially combined, may potentiate adipogenic effect of HFD. PMID:23657865

Tinkov, Alexey A; Polyakova, Valentina S; Nikonorov, Alexandr A

2013-06-01

69

Integration of nonlinear dielectric barium strontium titanate with polycrystalline yttrium iron garnet  

SciTech Connect

Biaxially oriented nonlinear dielectric Ba{sub 0.6}Sr{sub 0.4}TiO{sub 3} (BST) films have been grown on polycrystalline ferrite yttrium iron garnet (YIG) substrates. We use a structurally and chemically compatible MgO buffer to improve the crystallinity of the BST on polycrystalline YIG substrates, where the biaxially oriented MgO is deposited by an ion-beam assisted-deposition technique. The biaxially oriented BST has a dielectric loss of less than 0.01 and a capacitance tunability of greater than 25{percent} at a direct current bias voltage of 40 V at room temperature. {copyright} {ital 1999 American Institute of Physics.}

Jia, Q.X.; Groves, J.R.; Arendt, P.; Fan, Y.; Findikoglu, A.T.; Foltyn, S.R. [Superconductivity Technology Center, Mail Stop K763, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Superconductivity Technology Center, Mail Stop K763, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Jiang, H. [NZ Applied Technologies, 150-C New Boston Street, Woburn, Massachusetts 01801 (United States)] [NZ Applied Technologies, 150-C New Boston Street, Woburn, Massachusetts 01801 (United States); Miranda, F.A. [NASA Lewis Research Center, 21000 Brookpark Road, MS 54-5, Cleveland, Ohio 44135 (United States)] [NASA Lewis Research Center, 21000 Brookpark Road, MS 54-5, Cleveland, Ohio 44135 (United States)

1999-03-01

70

State of adsorption layers of fatty acids on the surfaces of iron, manganese, and copper ferrites  

NASA Astrophysics Data System (ADS)

States of adsorbed substances in surface layers arising during the adsorption of oleic, linoleic, and linolenic acids from carbon tetrachloride, heptane, and cyclohexane solutions on the surfaces of iron, manganese, and copper ferrites, are investigated. Adsorption isotherms and two-dimensional state diagrams of surface layers of iron, manganese, and copper ferrites are obtained experimentally. It is shown that the adsorption of fatty acids from solutions in organic solvents proceeds via filling the volume of the ferrites' porous space with adsorption solutions, while the state of ferrite surface layers changes due to the structural rearrangement of adsorption solutions upon an increase in solute concentration.

Balmasova, O. V.; Ramazanova, A. G.; Korolev, V. V.

2012-07-01

71

[Evaluation of iron, zinc and copper contents in selected spices available on the Polish market].  

PubMed

The aim of the study was to evaluate the content of iron, zinc and copper in selected spices (pepper, parsley, dill, thyme, oregano, basil, marjoram, rosemary, juniper) from three companies. The contents of minerals were determined by flame AAS. Statistical analysis was carried out employing the STATISTICA software and using the ANOVA test. The high content of minerals was found in basil. Juniper contains relatively low quantities of these elements. It was shown a significant differences in iron, zinc and copper content in spices come from different companies. PMID:22171516

Suliburska, Joanna; Kaczmarek, Karolina

2011-01-01

72

Trace Element Status (Iron, Zinc, Copper, Chromium, Cobalt, and Nickel) in Iron-Deficiency Anaemia of Children under 3 Years  

PubMed Central

Aim. To determine trace element status and aetiologic factors for development of trace elements deficiencies in children with iron-deficiency anaemia (IDA) aged 0 to 3 years. Contingent and Methods. 30 patients of the University Hospital, Pleven, Bulgaria—I group; 48 patients of the Sumy Regional Child's Clinical Hospital, Sumy, Ukraine—II group; 25 healthy controls were investigated. Serum concentrations of iron, zinc, copper, chromium, cobalt, and nickel were determined spectrophotometrically and by atomic absorption spectrophotometry. Results. Because the obtained serum levels of zinc, copper, and chromium were near the lower reference limits, I group was divided into IA and IB. In IA group, serum concentrations were lower than the reference values for 47%, 57%, and 73% of patients, respectively. In IB group, these were within the reference values. In II group, results for zinc, cobalt, and nickel were significantly lower (P < 0.05), and results for copper were significantly higher in comparison to controls. Conclusion. Low serum concentrations of zinc, copper, cobalt, and nickel were mainly due to inadequate dietary intake, malabsorption, and micronutrient interactions in both studied groups. Increased serum copper in II group was probably due to metabolic changes resulting from adaptations in IDA. Data can be used for developing a diagnostic algorithm for IDA.

Angelova, Maria Georgieva; Petkova-Marinova, Tsvetelina Valentinova; Pogorielov, Maksym Vladimirovich; Loboda, Andrii Nikolaevich; Nedkova-Kolarova, Vania Nedkova; Bozhinova, Atanaska Naumova

2014-01-01

73

Trace Element Status (Iron, Zinc, Copper, Chromium, Cobalt, and Nickel) in Iron-Deficiency Anaemia of Children under 3 Years.  

PubMed

Aim. To determine trace element status and aetiologic factors for development of trace elements deficiencies in children with iron-deficiency anaemia (IDA) aged 0 to 3 years. Contingent and Methods. 30 patients of the University Hospital, Pleven, Bulgaria-I group; 48 patients of the Sumy Regional Child's Clinical Hospital, Sumy, Ukraine-II group; 25 healthy controls were investigated. Serum concentrations of iron, zinc, copper, chromium, cobalt, and nickel were determined spectrophotometrically and by atomic absorption spectrophotometry. Results. Because the obtained serum levels of zinc, copper, and chromium were near the lower reference limits, I group was divided into IA and IB. In IA group, serum concentrations were lower than the reference values for 47%, 57%, and 73% of patients, respectively. In IB group, these were within the reference values. In II group, results for zinc, cobalt, and nickel were significantly lower (P < 0.05), and results for copper were significantly higher in comparison to controls. Conclusion. Low serum concentrations of zinc, copper, cobalt, and nickel were mainly due to inadequate dietary intake, malabsorption, and micronutrient interactions in both studied groups. Increased serum copper in II group was probably due to metabolic changes resulting from adaptations in IDA. Data can be used for developing a diagnostic algorithm for IDA. PMID:24839556

Angelova, Maria Georgieva; Petkova-Marinova, Tsvetelina Valentinova; Pogorielov, Maksym Vladimirovich; Loboda, Andrii Nikolaevich; Nedkova-Kolarova, Vania Nedkova; Bozhinova, Atanaska Naumova

2014-01-01

74

Phormidium autumnale Growth and Anatoxin-a Production under Iron and Copper Stress  

PubMed Central

Studies on planktonic cyanobacteria have shown variability in cyanotoxin production, in response to changes in growth phase and environmental factors. Few studies have investigated cyanotoxin regulation in benthic mat-forming species, despite increasing reports on poisoning events caused by ingestion of these organisms. In this study, a method was developed to investigate changes in cyanotoxin quota in liquid cultures of benthic mat-forming cyanobacteria. Iron and copper are important in cellular processes and are well known to affect growth and selected metabolite production in cyanobacteria and algae. The effect of iron (40–4000 ?g L?1) and copper (2.5–250 ?g L?1) on growth and anatoxin-a quota in Phormidium autumnale was investigated in batch culture. These concentrations were chosen to span those found in freshwater, as well as those previously reported to be toxic to cyanobacteria. Anatoxin-a concentrations varied throughout the growth curve, with a maximum quota of between 0.49 and 0.55 pg cell?1 measured within the first two weeks of growth. Growth rates were significantly affected by copper and iron concentrations (P < 0.0001); however, no statistically significant difference between anatoxin-a quota maxima was observed. When the iron concentrations were 800 and 4000 ?g L?1, the P. autumnale cultures did not firmly attach to the substratum. At 250 ?g L?1 copper or either 40 or 4000 ?g L?1 iron, growth was suppressed.

Harland, Francine M. J.; Wood, Susanna A.; Moltchanova, Elena; Williamson, Wendy M.; Gaw, Sally

2013-01-01

75

Diel cycles in dissolved barium, lead, iron, vanadium, and nitrite in a stream draining a former zinc smelter site near Hegeler, Illinois  

USGS Publications Warehouse

Diel variations in the concentrations of a number of constituents have the potential to substantially affect the appropriate sampling regimen in acidic streams. Samples taken once during the course of the day cannot adequately reflect diel variations in water quality and may result in an inaccurate understanding of biogeochemical processes, ecological conditions, and of the threat posed by the water to human health and the associated wildlife. Surface water and groundwater affected by acid drainage were sampled every 60 to 90. min over a 48-hour period at a former zinc smelter known as the Hegeler Zinc Superfund Site, near Hegeler, Illinois. Diel variations related to water quality in the aquifer were not observed in groundwater. Diel variations were observed in the temperature, pH, and concentration of dissolved oxygen, nitrite, barium, iron, lead, vanadium, and possibly uranium in surface water. Temperature, dissolved oxygen, nitrite, barium, lead, and uranium generally attained maximum values during the afternoon and minimum values during the night. Iron, vanadium, and pH generally attained minimum values during the afternoon and maximum values during the night. Concentrations of dissolved oxygen were affected by the intensity of photosynthetic activity and respiration, which are dependent upon insolation. Nitrite, an intermediary in many nitrogen reactions, may have been formed by the oxidation of ammonium by dissolved oxygen and converted to other nitrogen species as part of the decomposition of organic matter. The timing of the pH cycles was distinctly different from the cycles found in Midwestern alkaline streams and likely was the result of the photoreduction of Fe3+ to Fe 2+ and variations in the intensity of precipitation of hydrous ferric oxide minerals. Diel cycles of iron and vanadium also were primarily the result of variations in the intensity of precipitation of hydrous ferric oxide minerals. The diel variation in the concentrations of lead, uranium, and barium may have been affected by competition with Fe+2 for sorption sites on hydrous ferric oxide minerals. ?? 2010.

Kay, R. T.; Groschen, G. E.; Cygan, G.; Dupre, David, H. , D. H.

2011-01-01

76

The solubility of copper in lime-saturated and calcium ferrite-saturated liquid iron oxide  

Microsoft Academic Search

The solubility of copper in lime-saturated and calcium ferrite-saturated liquid iron oxide has been measured at 1300 ?C by\\u000a equilibrating copper-gold alloys with the melts in CO-CO2 atmospheres of oxygen potentials 10?7, 10?8, 10?9, and 10?10 atm. It was found that copper exhibits Henrian behavior in the oxide melts and that the solubility is given by\\u000a \\u000a \\u000a \\u000a \\u000a $$wt pct Cu =

J. Palacios; D. R. Gaskell

1993-01-01

77

Rates of dissolution of rotating iron cylinders in liquid copper and cu-fe alloys  

Microsoft Academic Search

Iron cylinders with molybdenum capped ends are rotated at speeds of 260, 570, and 835 rpm in liquid copper and Cu-Fe alloys\\u000a maintained at 1220?, 1300?C, and 1370?C under argon at 1 atm pressure. The dependence of the dissolution rate of the cylinders\\u000a on the concentration of iron in the bulk liquid is observed. The solution-rate constants defined by an

R. Ohno

1973-01-01

78

Kinetics of solution of hydrogen in liquid iron, nickel, and copper containing dissolved oxygen and sulfur  

Microsoft Academic Search

An investigation of the effect of surface active oxygen and sulfur on the rate of hydrogen solution in inductively stirred\\u000a liquid iron, nickel, and copper was made using a modified constant-volume Sieverts’ method. The overall and initial rates\\u000a of hydrogen solution in liquid iron and nickel were found to decrease with increasing oxygen content in concentration ranges\\u000a found in the

W. M. Small; R. H. Radzilowski; R. D. Pehlke

1973-01-01

79

Impact of Copper on an Alkali Promoted Iron Fischer–Tropsch Catalyst  

Microsoft Academic Search

Copper has traditionally been added to precipitated iron Fischer–Tropsch (FT) catalysts to facilitate reduction of Fe2O3 to zero valent iron during activation [M.E. Dry, in: J.R. Anderson and M. Boudart (eds), Catalysis Science and Technology, Vol. 1 (Springer-Verlag, New York, 1981) p. 179] by lowering the reduction temperature when activating with hydrogen, carbon monoxide or syngas [R.J. O'Brien et al.,

Robert J. O'Brien; Burtron H. Davis

2004-01-01

80

Effects of Copper and Austempering on Corrosion Behavior of Ductile Iron in 3.5 Pct Sodium Chloride  

NASA Astrophysics Data System (ADS)

Although alloying and heat treatments are common industrial practices to obtain ductile irons with desired mechanical properties, related information on how the two practices affect corrosion behavior is scarce. In this study, two ductile irons—with and without 1 wt pct copper addition—were austempered to obtain austempered ductile irons (ADIs). Polarization tests and salt spray tests were conducted to explore how both copper-alloying and austempering heat treatments influenced the corrosion behavior of ductile irons. The results showed that the corrosion resistance of 1 wt pct copper-alloyed ductile iron was better than that of the unalloyed one, while ADI had improved corrosion resistance compared with the as-cast. In particular, the ductile iron combined with the copper-alloying and austempering treatments increased the corrosion inhibition efficiency up to 84 pct as tested in 3.5 wt pct NaCl solution.

Hsu, Cheng-Hsun; Lin, Kuan-Ting

2013-10-01

81

Chemical vapor deposition of yttrium barium(2) copper(3) oxygen(x) thin films for wire applications. Final report, May 88-Dec 91  

SciTech Connect

The chemical vapor deposition of superconducting ytterbium barium copper oxide thin films onto continuous lengths of ceramic fiber tows has been investigated. This project couples two areas of current interest in the materials field: continuous fiber coating and the deposition of one of the unique high temperature superconducting oxides. The YBa2Cu3Ox material has zero resistance at temperatures above 77 K (the boiling point of nitrogen), and the film form has been shown to have high critical current densities. By coating ceramic fiber tows, a strong, flexible superconducting material in the form of wire can be developed and used for several applications, including coils for magnets and transmission lines. Over 900 deposition runs were completed using a horizontal CVD furnace and over 150 continuous fiber coating experiments were completed. The deposition was performed on fiber tows, flat samples, and flexible tapes; the continuous substrates were moved and held stationary in the furnace.

Lackey, W.J.; Hanigofsky, J.A.; Hill, D.N.; Carter, W.B.; Barefield, E.K.

1991-12-01

82

Nuclear magnetic resonance of iron and copper disease states  

Microsoft Academic Search

The tissue levels of paramagnetic ions are an important factor in the determination of T⁠values as observed by nuclear magnetic resonance (NMR) imaging. The increased levels of iron present in human disease states such as hemochromatosis lead to decreased T⁠values. The mean liver T⁠of three patients with iron storage disease was determined to be 130 msec, significantly

V. M. Runge; J. A. Clanton; F. W. Smith; J. Hutchison; J. Mallard; C. L. Partain; A. E. Jr. James

1983-01-01

83

Decomposition of the sulfates of copper, iron (II), iron (III), nickel, and zinc: XPS, SEM, DRIFTS, XRD, and TGA study  

NASA Astrophysics Data System (ADS)

The bulk and surface characteristics during decomposition of the transition metal sulfates of copper, iron (II), iron (III), nickel, and zinc are investigated utilizing various spectroscopic techniques. An oxidized form of sulfur was detected on the surface during decomposition of all metal sulfate samples, except zinc sulfate. Surface characteristics were not necessarily representative of the bulk characteristics. Oxy-sulfate was observed with copper sulfate only. Lower decomposition temperatures were observed in vacuum as compared to those at atmospheric pressure. Uniform sulfur distribution was observed across sample cross sections. Analysis consisted of Scanning electron microscopy/X-ray microanalysis, X-ray photoelectron spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, thermogravimetric analysis, and X-ray diffraction.

Siriwardane, Ranjani V.; Poston, James A., Jr.; Fisher, Edward P.; Shen, Ming-Shing; Miltz, Angela L.

1999-11-01

84

Comparative Effects of Copper, Iron, Vanadium and Titanium on Low Density Lipoprotein Oxidation in vitro  

Microsoft Academic Search

Introduction: Oxidation of low density lipoprotein (LDL) has been strongly implicated in the phathogenesis of atherosclerosis. The use of oxidants in dietary food stuff may lead to the production of oxidized LDL and may increase both the development and the progression of atherosclerosis. The present work investigated the effects of some elements including: copper (Cu), iron (Fe), vanadium (V) and

Mohsen Ani; Ali Asghar Moshtaghie; Hassan Ahmadvand

2007-01-01

85

Determination of Iron, Nickel, Copper, and Cobalt in Tungsten and Tungsten Alloys.  

National Technical Information Service (NTIS)

Iron, nickel, copper, and cobalt in tungsten and tungsten alloys are analyzed spectrophotometrically by taking aliquots of a hydrofluoricnitric acid solution that has been buffered to a pH of 6 by the addition of ammonium tartrate and sodium borate. No su...

G. Norwitz H. Gordon

1964-01-01

86

Influences of Water Treatment Process on Iron and Copper Release in Distribution System  

Microsoft Academic Search

A pilot study was conducted to assess the effect of water quality changes on iron and copper release in distribution systems. Three finished waters were prepared from groundwater source by conventional treatment, lime softening and reverse osmosis (RO). To mimic desalinated seawater, sea salts were added to RO treated water. Both lime softening and RO treatment significantly decreased the calcium

Baoyou Shi; Weizhong Xiao; James S. Taylor

2006-01-01

87

Some effects of oral ingestion of cadmium on zinc, copper, and iron metabolism  

Microsoft Academic Search

Several biological effects that reflect the interaction of cadmium and zinc when cadium is ingested by rats are described. Data from several reports and investigations show that the ingestion of low levels of cadmium by rats can cause alteration of zinc metabolism in the liver, emphysema, reduced pulmonary function, depression of copper and iron metabolism in the rat fetus, growth

H. G. Petering; H. Choudhury; K. L. Stemmer

1979-01-01

88

Djerfisherite, alkali copper-iron sulfide: a new mineral from enstatite chondrites.  

PubMed

A new mineral, essentially a potassium-copper-iron sulfide, occurs in accessory amounts in the enstatite chondrites Kota Kota (a find) and St. Marks (a fall), and has been identified visually in the enstatite achondrite Pena Blanca Springs (a fall). The x-ray diffraction pattern, electron-microprobe analysis, and its appearance in polished sections all serve to identify it. PMID:17831500

Fuchs, L H

1966-07-01

89

Oxidative stress-mediated hepatotoxicity of iron and copper: Role of Kupffer cells  

Microsoft Academic Search

Iron- or copper-mediated catalysis leads to the generation of reactive oxygen species (ROS) that can attack biomolecules directly, with the consequent enhancement in membrane lipid peroxidation, DNA damage, and protein oxidation. Reactive nitrogen species (RNS) can also be formed, leading to nitration of aromatic structures in addition to the oxidative deterioration of cellular components. Kupffer cells, the resident macrophages of

Luis A. Videla; Virginia Fernández; Gladys Tapia; Patricia Varela

2003-01-01

90

Absorption of gaseous oxygen by liquid cobalt, copper, iron and nickel  

Microsoft Academic Search

An experimental investigation of the rates of oxygen solution in molten cobalt, copper, iron and nickel was carried out using pure oxygen and a constant-volume Sieverts' method. It was found that the volume of gaseous oxygen which initially reacted with the inductively stirred metals was strongly dependent on the physical nature of the oxide film which formed during the first

R. H. Radzilowski; R. D. Pehlke

1978-01-01

91

Fast method for the determination of copper, manganese and iron in seafood samples  

Microsoft Academic Search

A slurry sampling flame atomic absorption spectrometric method is proposed for the determination of copper, manganese and iron in oysters (Crassostrea rhizophora), clams (Anomalocardia brasiliana) and mussels (Mytella guiyanensis; Perna perna). Optimization was carried out using univariate methodology involving the following variables: nature and concentration of the acid solution for slurry preparation, sonication time and sample mass. The optimized conditions

Erik G. P. da Silva; Vanessa Hatje; Walter N. L. dos Santos; Letícia M. Costa; Ana R. A. Nogueira; Sérgio L. C. Ferreira

2008-01-01

92

Vitreous Analysis in Eyes Containing Copper and Iron Intraocular Foreign Bodies.  

National Technical Information Service (NTIS)

The analysis of vitreous to determine the presence and metallic type of an intraocular foreign body appears to be a rapid and reliable diagnostic technique with few limitations. In this study, copper and iron were selected for evaluation because these met...

T. E. Runyan E. A. Levri

1970-01-01

93

Zinc, copper, iron, and chromium concentrations in young patients with type 2 diabetes mellitus.  

PubMed

Homeostasis of trace elements can be disrupted by diabetes mellitus. On the other hand, disturbance in trace element status in diabetes mellitus may contribute to the insulin resistance and development of diabetic complications. The aim of present study was to compare the concentration of essential trace elements, zinc, copper, iron, and chromium in serum of patients who have type 2 diabetes mellitus (n = 20) with those of nondiabetic control subjects (n = 20). The serum concentrations of zinc, copper, iron, and chromium were measured by means of an atomic absorption spectrophotometer (Shimadzu AA 670, Kyoto, Japan) after acid digestion. The results of this study showed that the mean values of zinc, copper, and chromium were significantly lower in the serum of patients with diabetes as compared to the control subjects (P < 0.05). Our results show that deficiency of some essential trace elements may play a role in the development of diabetes mellitus. PMID:22351156

Basaki, M; Saeb, M; Nazifi, S; Shamsaei, H A

2012-08-01

94

MD description of damage production in displacement cascades in copper and ?-iron  

NASA Astrophysics Data System (ADS)

Molecular dynamics computer simulation was applied for an extensive study of primary damage creation in displacement cascades in copper and ?-iron. Primary knock-on atom energy, Ep, of up to 25 keV in copper and 100 keV in iron was considered for irradiation temperatures in the range 100-900 K. Special attention was paid to comprehensive statistical treatment of the number and type of defects created in cascades by conducting multiple simulations for each value of energy and temperature. The total number of point defects per cascade is significantly lower than that predicted by the NRT model and rather similar in the two metals. The fraction of self-interstitial atoms (SIAs) and vacancies that agglomerate in clusters in the cascade process was analysed in detail. The clustered fraction of SIAs increases with temperature increase and is larger in copper than iron. SIA clusters have a variety of forms in both metals and, although most are glissile clusters of parallel crowdions, a significant fraction are sessile. The latter include Frank dislocation loops in copper. Tightly packed arrangements of vacancies do not form in iron, and so the fraction of clustered vacancies depends strongly on the range within which point defects are defined to be near-neighbours. Arrangements of vacancies in first-neighbour sites are common in copper. Most are irregular stacking fault tetrahedra (SFTs). In 53 simulations of cascades with Ep=25 keV at 100 K, the largest cluster formed contained 89 vacancies. The size spectrum of SFT-like clusters is similar to that found experimentally in neutron-irradiated copper, suggesting that the SFTs observed in experiment are formed directly in the cascade process.

Bacon, D. J.; Osetsky, Yu. N.; Stoller, R.; Voskoboinikov, R. E.

2003-12-01

95

MD description of damage production in displacement cascades in copper and ?-iron.  

SciTech Connect

Molecular dynamics computer simulation was applied for an extensive study of primary damage creation in displacement cascades in copper and {alpha}-iron. Primary knock-on atom energy, E{sub p}, of up to 25 keV in copper and 100 keV in iron was considered for irradiation temperatures in the range 100-900 K. Special attention was paid to comprehensive statistical treatment of the number and type of defects created in cascades by conducting multiple simulations for each value of energy and temperature. The total number of point defects per cascade is significantly lower than that predicted by the NRT model and rather similar in the two metals. The fraction of self-interstitial atoms (SIAs) and vacancies that agglomerate in clusters in the cascade process was analysed in detail. The clustered fraction of SIAs increases with temperature increase and is larger in copper than iron. SIA clusters have a variety of forms in both metals and, although most are glissile clusters of parallel crowdions, a significant fraction are sessile. The latter include Frank dislocation loops in copper. Tightly packed arrangements of vacancies do not form in iron, and so the fraction of clustered vacancies depends strongly on the range within which point defects are defined to be near-neighbours. Arrangements of vacancies in first-neighbour sites are common in copper. Most are irregular stacking fault tetrahedra (SFTs). In 53 simulations of cascades with E{sub p} = 25 keV at 100 K, the largest cluster formed contained 89 vacancies. The size spectrum of SFT-like clusters is similar to that found experimentally in neutron-irradiated copper, suggesting that the SFTs observed in experiment are formed directly in the cascade process.

Bacon, David J [University of Liverpool; Osetskiy, Yury N [ORNL; Stoller, Roger E [ORNL; Voskoboinikov, Roman E [University of Liverpool

2003-01-01

96

Iron-copper metallization for flexible solar/cell arrays  

NASA Astrophysics Data System (ADS)

The feasibility of a copper-base metallization for shallow-junction cells applied in flexible solar arrays in space is discussed. This type of metallization will reduce usage of precious metals (such as silver), increase case of bonding (by welding or by soldering) and eliminate heavy high Z interconnects (such as molybdenum). The main points of concern are stability against thermally induced diffusion of copper into silicon which causes degradation of shallow cell junctions, and low series resistance of the contact with semiconductor which promotes cell efficiency.

Lavendel, H. W.

1983-11-01

97

Zinc pyrithione inhibits yeast growth through copper influx and inactivation of iron-sulfur proteins.  

PubMed

Zinc pyrithione (ZPT) is an antimicrobial material with widespread use in antidandruff shampoos and antifouling paints. Despite decades of commercial use, there is little understanding of its antimicrobial mechanism of action. We used a combination of genome-wide approaches (yeast deletion mutants and microarrays) and traditional methods (gene constructs and atomic emission) to characterize the activity of ZPT against a model yeast, Saccharomyces cerevisiae. ZPT acts through an increase in cellular copper levels that leads to loss of activity of iron-sulfur cluster-containing proteins. ZPT was also found to mediate growth inhibition through an increase in copper in the scalp fungus Malassezia globosa. A model is presented in which pyrithione acts as a copper ionophore, enabling copper to enter cells and distribute across intracellular membranes. This is the first report of a metal-ligand complex that inhibits fungal growth by increasing the cellular level of a different metal. PMID:21947398

Reeder, Nancy L; Kaplan, Jerry; Xu, Jun; Youngquist, R Scott; Wallace, Jared; Hu, Ping; Juhlin, Kenton D; Schwartz, James R; Grant, Raymond A; Fieno, Angela; Nemeth, Suzanne; Reichling, Tim; Tiesman, Jay P; Mills, Tim; Steinke, Mark; Wang, Shuo L; Saunders, Charles W

2011-12-01

98

Magnetic effects of hydrothermal alteration in porphyry copper and iron-oxide copper-gold systems: A review  

NASA Astrophysics Data System (ADS)

Magnetic anomaly patterns can be used as a tool for mapping lithology, metamorphic zones and hydrothermal alteration systems, as well as identifying structures that may control passage of magmas or hydrothermal fluids associated with mineralisation. Reliable geological interpretation of mineralised systems requires an understanding of the magmatic, metamorphic and hydrothermal processes that create, alter and destroy magnetic minerals in rocks. Predictive magnetic exploration models for porphyry copper and iron oxide copper-gold (IOCG) deposits can be derived from standard geological models by integrating magnetic petrological principles with petrophysical data, deposit descriptions, and modelling of observed magnetic signatures of these deposits. Even within a particular geological province, the magnetic signatures of similar deposits may differ substantially, due to differences in the local geological setting. Searching for “look-alike” signatures of a known deposit is likely to be unrewarding unless pertinent geological factors are taken into account. These factors include the tectonic setting and magma type, composition and disposition of host rocks, depth of emplacement and post-emplacement erosion level, depth of burial beneath younger cover, post-emplacement faulting and tilting, remanence effects contingent on ages of intrusion and alteration, and metamorphism. Because the effects of these factors on magnetic signatures are reasonably well understood, theoretical magnetic signatures appropriate for the local geological environment can qualitatively guide exploration and make semiquantitative predictions of anomaly amplitudes and patterns. The predictive models also allow detectability of deposit signatures to be assessed, for example when deposits are buried beneath a considerable thickness of nonmagnetic overburden, are covered by highly magnetic heterogeneous volcanic rocks, or there is a strong regional magnetic gradient. This paper reviews the effects of hydrothermal alteration on magnetic properties and magnetic signatures of porphyry copper and iron oxide copper-gold systems and presents examples of predictive magnetic exploration models, and their predicted signatures, in various geological circumstances.

Clark, David A.

2014-06-01

99

Fabrication of a nanocomposite from in situ iron nanoparticle reinforced copper alloy.  

PubMed

In situ iron nanoparticle reinforced Cu-3Sn-8Zn-6Pb alloy has been fabricated by centrifugal casting in a vacuum chamber with a medium frequency electrical furnace. The microstructure of this alloy was analyzed with a scanning electron microscope (SEM) and a high-resolution transmission electron microscope (HRTEM), and the results show that the grains of Cu-3Sn-8Zn-6Pb alloy without iron have a typical dendrite structure with dimensions from 500 to 1500 microm, and the grains of the alloy with the addition of 1% iron are small and equiaxed, with dimensions from 20 to 60 microm. Then, the relatively uniform dispersed particles in the copper matrix were identified with the HRTEM to be pure iron with dimensions in the order of 2-20 nm. The mechanical properties of the alloys were measured and the results show a significant increase in the tensile strength of the alloy with iron nanoparticles and a slight increase of the elongation compared to that without iron. The mechanism of formation of the iron nanoparticles was analyzed by thermodynamic and dynamic theories, and the results indicate that the in situ iron nanoparticles of Cu-3Sn-8Zn-6Pb alloy can reasonably form during solidification in the centrifugal casting technique. PMID:19417426

Wang, Zidong; Wang, Xuewen; Wang, Qiangsong; Shih, I; Xu, J J

2009-02-18

100

Summary of ENDF/B-V evaluations for carbon, calcium, iron, copper, and lead and ENDF/B-V Revision 2 for calcium and iron  

SciTech Connect

This report, together with documents already published, describes the ENDF/B-V evaluations of the neutron and gamma-ray-production cross sections for carbon, calcium, iron, copper, and lead and the ENDF/B-V Revision 2 evaluations for calcium and iron.

Fu, C Y

1982-09-01

101

Direct Functionalization of (Un)protected Tetrahydroisoquinoline and Isochroman under Iron and Copper Catalysis: Two Metals, Two Mechanisms  

PubMed Central

A highly facile, straightforward synthesis of 1-(3-indolyl)-tetrahydroisoquinolines was developed using either simple copper or iron catalysts. N-protected and unprotected tetrahydroisoquinolines (THIQ) could be used as starting materials. Extension of the substrate scope of the pronucleophile from indoles to pyrroles and electron-rich arenes was realized. Additionally, methoxyphenylation is not limited to THIQ but can be carried out on isochroman as well, again employing iron and copper catalysis.

2011-01-01

102

The influence of selected antihypertensive drugs on zinc, copper, and iron status in spontaneously hypertensive rats.  

PubMed

Mineral homeostasis in hypertensive patients may be affected by hypotensive drugs. The aim of this study was to assess the influence of selected antihypertensive drugs on mineral homeostasis in a rat model of hypertension. Eight-week-old male spontaneously hypertensive rats (SHRs) were treated with perindopril, metoprolol, indapamide, amlodipine, or no drug for 45 days. In another experiment, the SHRs were treated with indapamide or amlodipine in the presence of zinc and copper gluconate supplement. Lipids, glucose, and insulin levels along with superoxide dismutase and catalase activities were assayed in serum. Iron, zinc, and copper concentrations in serum, erythrocytes, and tissues were determined using the flame atomic absorption spectrometry. Blood pressure was measured using a tail-cuff plethysmograph. Treatment with indapamide and amlodipine was found to significantly lower zinc levels in serum, erythrocytes, livers, and spleens of the SHRs, as well as copper levels in the kidneys, compared with the control no-drug group. A markedly higher concentration of glucose was found in the indapamide-treated rats. Supplementing the indapamide-treated SHRs with zinc and copper gluconate resulted in a significant decrease in both systolic and diastolic blood pressure, and also lowered serum glucose and triglyceride concentrations and HOMA (homeostasis model assessment-insulin resistance) values. The results show that indapamide and amlodipine disturb zinc and copper homeostasis in SHRs. Supplementation with zinc and copper restores mineral homeostasis in SHRs treated with indapamide and amlodipine, and also corrects metabolic imbalances while improving the antihypertensive efficiency of indapamide. PMID:24927993

Suliburska, Joanna; Bogdanski, Pawe?; Jakubowski, Hieronim

2014-09-01

103

Some effects of oral ingestion of cadmium on zinc, copper, and iron metabolism.  

PubMed Central

Data are presented to show that ingestion of cadmium chloride by rats at low levels leads to alteration of zinc metabolism in the liver, even though the formation of metallothionein is not evident. A dose-response relationship between amount of cadmium ingested and degree of perturbation of zinc metabolism in liver was found. Oral cadmium was shown to cause emphysema and reduce pulmonary function in male rats; the effect was less severe or delayed in onset if dietary zinc concentration was high. Interference with copper and iron metabolism was shown to occur in rats given low levels of cadmium orally. Depression of copper and iron metabolism of the rat fetus was found to occur when dams received very low doses of cadmium during gestation, even though very little cadmium passed the placental barrier. Images FIGURE 1. a FIGURE 1. b FIGURE 2. a FIGURE 2. b

Petering, H G; Choudhury, H; Stemmer, K L

1979-01-01

104

Generation of oxidant response to copper and iron nanoparticles and salts: Stimulation by ascorbate  

PubMed Central

The present work describes a two-stage approach to analyzing combustion-generated samples for their potential to produce oxidant stress. This approach is illustrated with the two commonly encountered transition metals, copper and iron. First, their abilities to generate hydroxyl radical were measured in a cell-free, phosphate-buffered saline solution containing ascorbate and/or citrate. Second, their abilities to induce heme oxygenase-1 in cultured human epidermal keratinocytes were assessed in cell culture. Combustion-generated copper oxide nanoparticles were active in both assays and were found to be soluble in culture medium. Depletion of glutathione in the cells or loading the cells with ascorbate greatly increased heme oxygenase-1 induction in the presence of copper. By contrast, iron oxide nanoparticles were active in the phosphate buffered saline but not in cell culture, and they aggregated in culture medium. Soluble salts of copper and iron exhibited the same contrast in activities as the respective combustion-generated particles. The results suggest that the capability of combustion-generated environmental samples to produce oxidant stress can be screened effectively in a two step process, first in phosphate buffered saline with ascorbate and subsequently in epithelial cell culture for those exhibiting activity initially. The results also point to an unanticipated interaction in cells of oxidant stress-generating metals with an anti-oxidant (ascorbate) that is usually missing in culture medium formulations. Thus, ascorbate supplementation of cultured human cells is likely to improve their ability to model the in vivo effects of particulate matter containing copper and other redox-active metals.

Rice, Robert H.; Vidrio, Edgar A.; Kumfer, Benjamin M.; Qin, Qin; Willits, Neil H.; Kennedy, Ian M.; Anastasio, Cort

2009-01-01

105

Effect of sulfite exposure on zinc, iron, and copper levels in rat liver and kidney tissues  

Microsoft Academic Search

Sulfite is a potentially toxic molecule that might enter the body via ingestion, inhalation, or injection. For cellular detoxification,\\u000a mammalians rely on sulfite oxidase to convert sulfite to sulfate. The purpose of this research was to determine the effect\\u000a of sulfite on zinc, iron, and copper levels in rat liver and kidney tissues. Forty normal and sulfite oxidase-deficient male\\u000a albino

Vural Kucukatay; Sebahat Turgut; Erdogan Kocamaz; Gulten Emmungil; Melek Bor-Kucukatay; Gunfer Turgut; Hakan Akca; Huseyin Bagci

2006-01-01

106

Effect of Copper on the Decomposition of Ethylene over an Iron Catalyst  

Microsoft Academic Search

The catalytic properties of a series of unsupported copper–iron powders of varying composition were investigated by using a probe reaction of ethylene and hydrogen at temperatures over the range 450 to 800°C. Analysis of both the gas-phase products and the solid carbon, mainly in the form of filamentous structures, produced during the reaction provided anin situmethod for monitoring the changes

N. Krishnankutty; N. M. Rodriguez; R. T. K. Baker

1996-01-01

107

Copper, Chromium, Manganese, Iron, Nickel, and Zinc Levels in Biological Samples of Diabetes Mellitus Patients  

Microsoft Academic Search

There is accumulating evidence that the metabolism of several trace elements is altered in diabetes mellitus and that these\\u000a nutrients might have specific roles in the pathogenesis and progress of this disease. The aim of present study was to compare\\u000a the level of essential trace elements, chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), and zinc (Zn) in

Tasneem Gul Kazi; Hassan Imran Afridi; Naveed Kazi; Mohammad Khan Jamali; Mohammad Bilal Arain; Nussarat Jalbani; Ghulam Abbas Kandhro

2008-01-01

108

Regional distribution of manganese, iron, copper, and zinc in the rat brain during development  

Microsoft Academic Search

Manganese (Mn), iron (Fe), copper (Cu), and zinc (Zn) concentrations were determined in the brain regions of normal 1-, 3-, 5-, 7-, 14-, 21-, 42-, 77-, and 147-day-old Wistar rats using inductively coupled plasma mass spectrometry (ICP-MS), and their maps were illustrated in color to visually compare the distribution of the elements at various stages of the growth process. Sagittal

Tohru Tarohda; Masayoshi Yamamoto; Ryohei Amamo

2004-01-01

109

Absorption of gaseous oxygen by liquid cobalt, copper, iron and nickel  

Microsoft Academic Search

An experimental investigation of the rates of oxygen solution in molten cobalt, copper, iron and nickel was carried out using\\u000a pure oxygen and a constant-volume Sieverts' method. It was found that the volume of gaseous oxygen which initially reacted\\u000a with the inductively stirred metals was strongly dependent on the physical nature of the oxide film which formed during the\\u000a first

R. H. Radzilowski; R. D. Pehlke

1978-01-01

110

Absorption of gaseous oxygen by liquid cobalt, copper, iron and nickel  

Microsoft Academic Search

An experimental investigation of the rates of oxygen solution in molten cobalt, copper, iron and nickel was carried out using\\u000a pure oxygen and a constant-volume Sieverts’ method. It was found that the volume of gaseous oxygen which initially reacted\\u000a with the inductively stirred metals was strongly dependent on the physical nature of the oxide film which formed during the\\u000a first

R. H. Radzilowski; R. D. Pehlke

1978-01-01

111

Determination of lead, copper, zinc, magnesium, calcium and iron in fresh eggs by atomic absorption spectrometry  

Microsoft Academic Search

In this study, lead, copper and zinc, calcium, magnesium and iron in fresh egg samples have been determined by electrothermal and flame atomic absorption spectrometry (ETAAS–FAAS) with Zeeman-effect background correction. Y+Pd+citric acid (CA) has been found a powerful modifier mixture for the determination of Pb, Cu and Zn. Maximum pyrolysis and optimum atomization temperatures of analyte elements were determined in

Ziya Kiliç; Orhan Acar; Mehmet Ula?an; Murat Ilim

2002-01-01

112

Evidence that intrinsic iron but not intrinsic copper determines S-nitrosocysteine decomposition in buffer solution  

Microsoft Academic Search

The present experiments were designed to analyze the influence of copper and iron ions on the process of decomposition of S-nitrosocysteine (cysNO), the most labile species among S-nitrosothiols (RSNO). CysNO fate in buffer solution was evaluated by optical and electron paramagnetic resonance (EPR) spectroscopy, and the consequences on its vasorelaxant effect were studied on noradrenaline-precontracted rat aortic rings. The main

Anatoly F. Vanin; Bernard Muller; Jacicarlos L. Alencar; Irina I. Lobysheva; Françoise Nepveu; Jean-Claude Stoclet

2002-01-01

113

Presence of acute phase changes in zinc, iron, and copper metabolism in turkey embryos  

SciTech Connect

Acute phase changes in trace mineral metabolism were examined in turkey embryos. An endotoxin injection resulted in increased concentrations of serum copper and liver zinc and decreased concentrations of serum zinc in embryos incubated either in ovo or ex ovo. Changes in zinc and copper metabolism occurred when endotoxin either was injected intramuscularly, into the amnionic fluid, or administered onto the chorioallantoic membrane. Unlike poults, embryos did not respond to an inflammatory challenge with decreased serum iron concentrations. Acute phase changes in embryo serum zinc and copper as well as liver zinc concentrations were similar to those in poults. Increased liver zinc concentrations were associated with increased zinc in metallothionein (MT). An injection of a crude interleukin 1 preparation into embryos resulted in similar increases in hepatic zinc and MT concentrations as an endotoxin injection, suggesting a role for this cytokine in mediating the acute phase changes in embryonic zinc metabolism.

Klasing, K.C.; Richards, M.P.; Darcey, S.E.; Laurin, D.E.

1987-01-01

114

Property and microstructural nonuniformity in the yttrium-barium-copper-oxide superconductor determined from electrical, magnetic, and ultrasonic measurements. Ph.D. Thesis - Case Western Reserve Univ.  

NASA Technical Reports Server (NTRS)

The purpose of this dissertation was the following: (1) to characterize the effect of pore fraction on a comprehensive set of electrical and magnetic properties for the yttrium-barium-copper-oxide (YBCO) high temperature ceramic superconductor; and (2) to determine the viability of using a room-temperature, nondestructive characterization method to aid in the prediction of superconducting (cryogenic) properties. The latter involved correlating ultrasonic velocity measurements at room temperature with property-affecting pore fraction and oxygen content variations. The use of ultrasonic velocity for estimating pore fraction in YBCO is presented, and other polycrystalline materials are reviewed, modeled, and statistically analyzed. This provides the basis for using ultrasonic velocity to interrogate microstructure. The effect of pore fraction (0.10-0.25) on superconductor properties of YBCO samples was characterized. Spatial (within-sample) variations in microstructure and superconductor properties were investigated, and the effect of oxygen content on elastic behavior was examined. Experimental methods used included a.c. susceptibility, electrical, and ultrasonic velocity measurements. Superconductor properties measured included transition temperature, magnetic transition width, transport and magnetic critical current density, magnetic shielding, a.c. loss, and sharpness of the voltage-current characteristics. An ultrasonic velocity image constructed from measurements at 1mm increments across a YBCO sample revealed microstructural variations that correlated with variations in magnetic shielding and a.c. loss behavior. Destructive examination using quantitative image analysis revealed pore fraction to be the varying microstructural feature.

Roth, Don J.

1991-01-01

115

A Study of the Density of Unfilled States in Yttrium Barium Copper Oxide by means of Soft X-ray Continuum Isochromats  

NASA Astrophysics Data System (ADS)

The New Mexico State University two-crystal X-ray spectrometer is designed for spectroscopy in the soft X-ray region. It has a demountable ultra-high vacuum X-ray tube and is equipped with Potassium Acid Phthalate (KAP) crystals and a flowing gas proportional counter. The KAP crystals provide a unique and sensitive spectral window at a photon energy of 530 eV. The high signal to background available makes it possible to record continuum limit spectra as continuum isochromats. We intend to obtain continuum isochromats at 530 eV from Yttrium Barium Copper Oxide, a high temperature superconductor. Such spectra are convolutions of the energy spectrum of the incident electrons in the target with the product of the density of unfilled states and a matrix element for the transition. The spectrum of initially mono-energetic electrons in the target can be derived from equivalent photoemission experiments and used to obtain a representation of the density of unfilled states above the Fermi level of the target material from the isochromat spectra.

Rajaram, Ramya; Liefeld, Robert

2002-10-01

116

A comparative study of thermal behavior of iron and copper nanofluids  

NASA Astrophysics Data System (ADS)

Nanofluids consist of nanoparticles dispersed in heat transfer carrier fluid and are typically used for enhancing thermal conductivity in devices and systems. This study investigated the synthesis of iron and copper nanoparticle-based thermal fluids prepared using a two-step process. Chemical precipitation was used for the synthesis of the powders, and ultrasonic irradiation was used to disperse the nanoparticles in the carrier fluid (ethylene glycol). The size distributions of the nanopowders in the carrier fluid were determined using dynamic light scattering resulting in average particle sizes of around 500 nm. The crystallite sizes of the powders were below 20 nm. Thus, both types of nanofluids are comparable with regard to crystallite size, particle size, and morphology resulting in a direct comparison of material properties and their effect on thermal conductivity of the nanofluids. A guarded hot parallel-plate method and dynamic tests were used to compare the thermal conductivities of the nanofluids. It was shown that thermal conductivity can be enhanced by up to 70% for copper nanofluids. It was also demonstrated that for a given particle concentration, copper nanofluids are superior in thermal conductivity compared to iron nanofluids.

Sinha, Kaustav; Kavlicoglu, Barkan; Liu, Yanming; Gordaninejad, Faramarz; Graeve, Olivia A.

2009-09-01

117

Zebrafish in the sea of mineral (iron, zinc, and copper) metabolism.  

PubMed

Iron, copper, zinc, and eight other minerals are classified as essential trace elements because they present in minute in vivo quantities and are essential for life. Because either excess or insufficient levels of trace elements can be detrimental to life (causing human diseases such as iron-deficiency anemia, hemochromatosis, Menkes syndrome and Wilson's disease), the endogenous levels of trace minerals must be tightly regulated. Many studies have demonstrated the existence of systems that maintain trace element homeostasis, and these systems are highly conserved in multiple species ranging from yeast to mice. As a model for studying trace mineral metabolism, the zebrafish is indispensable to researchers. Several large-scale mutagenesis screens have been performed in zebrafish, and these screens led to the identification of a series of metal transporters and the generation of several mutagenesis lines, providing an in-depth functional analysis at the system level. Moreover, because of their developmental advantages, zebrafish have also been used in mineral metabolism-related chemical screens and toxicology studies. Here, we systematically review the major findings of trace element homeostasis studies using the zebrafish model, with a focus on iron, zinc, copper, selenium, manganese, and iodine. We also provide a homology analysis of trace mineral transporters in fish, mice and humans. Finally, we discuss the evidence that zebrafish is an ideal experimental tool for uncovering novel mechanisms of trace mineral metabolism and for improving approaches to treat mineral imbalance-related diseases. PMID:24639652

Zhao, Lu; Xia, Zhidan; Wang, Fudi

2014-01-01

118

Effects of selenium on liver and muscle contents and urinary excretion of zinc, copper, iron and manganese.  

PubMed

Selenium is a main component of glutathione peroxidase (GPX), a key antioxidant enzyme. Other elements, such as zinc, copper, manganese and iron, are also involved in the pathogenesis of oxidative damage as well as in other important metabolic pathways. The effects of selenium supplementation on the metabolism of these elements have yield controversial results .The aim of this study is to analyse the effects of selenium supplementation on liver, muscle and urinary excretion of zinc, copper, iron and manganese in a situation of oxidative stress, such as protein deficiency. The experimental design included four groups of adult male Sprague-Dawley rats, which received the Lieber-DeCarli control diet, an isocaloric 2 % protein-containing diet and another similar two groups to which selenomethionine (6 mg/l liquid diet) was added. After sacrifice (5 weeks later), muscle, liver and serum selenium were determined, as well as muscle, liver and urinary zinc, copper, manganese and iron and liver GPX activity and liver malondialdehyde. Selenium addition led to decreased liver copper, increased muscle copper, increased copper excretion and increased liver iron, whereas zinc and manganese parameters were essentially unaltered. Muscle, liver and serum selenium were all significantly correlated with liver GPX activity. PMID:24622908

Monedero-Prieto, María José; González-Pérez, José María; González-Reimers, Emilio; Hernández-Pérez, Onán; Monereo-Muñoz, María; Galindo-Martín, Luis; Quintero-Platt, Geraldine; Abreu-González, Pedro

2014-05-01

119

Copper, iron and zinc absorption, retention and status of young women fed vitamin B-6 deficient diets  

SciTech Connect

A study was conducted in young women to determine the effect of vitamin B-6 deficient diets on copper, iron and zinc metabolism. Young women were confined to a metabolic research unit for 84 and 98 days. They were fed a vitamin B-6 deficient formula diet initially, followed by food diet containing four increasing levels of vitamin B-6. Copper, iron and zinc absorption, retention and status were determined at intervals throughout the study. Absorption was determined using the stable isotopes {sup 65}Cu, {sup 54}Fe, and {sup 67}Zn. Status was based on serum copper and zinc, hemoglobin, hematocrit and mean corpuscular volume. Copper absorption averaged 18 {plus minus} 1% during vitamin B-6 depletion, significantly lower than 24 {plus minus} 1% during repletion, but serum copper was not affected and balance was positive. Iron absorption was not impaired significantly by vitamin B-6 deficient diets, but status declined during the depletion period. Zinc absorption averaged 40 {plus minus} 2% during depletion and 27 {plus minus} 2% during repletion. Zinc absorption and retention were significantly greater during vitamin B-6 depletion, but serum zinc declined suggesting the absorbed zinc was not available for utilization. The results suggest that vitamin B-6 depletion of young women may inhibit copper absorption, affect iron status and alter zinc metabolism. The effects of vitamin B-6 depletion differ markedly among these elements.

Turnlund, J.R.; Keyes, W.R.; Hudson, C.A.; Betschart, A.A.; Kretsch, M.J.; Sauberlich, H.E. (USDA/ARS, San Francisco, CA (United States) Western Regional Research Center, Albany, CA (United States))

1991-03-11

120

Shift of the Fermi level during cointercalation of copper and iron into TiSe2  

NASA Astrophysics Data System (ADS)

The influence of copper intercalation into the TiSe2 compound on the Fermi energy has been investigated using two independent methods. The first method is based on the analysis of the amplitude of the deformation (induced by impurity intercalation and providing the formation of polarons) as a function of the binding energy of the band of polaron states. For this purpose, the Fe x Cu y TiSe2 system has been synthesized for the first time by cointercalation of copper and iron into the TiSe2 lattice and studied. The second method consists in measuring the electromotive force of an open-circuit electrochemical cell with respect to a metal reference electrode. Both methods lead to consistent results in the range of moderate copper contents. However, considerable discrepancies have been observed in the copper concentration range that corresponds to the beginning of filling of Cu/Ti hybrid states. These discrepancies are explained by the softening of the lattice due to an increase in the density of states at the Fermi level.

Titov, A. A.; Titov, A. N.; Bushkova, O. V.; Tsurin, V. A.

2010-08-01

121

The role of iron and copper molecules in the neuronal vulnerability of locus coeruleus and substantia nigra during aging  

PubMed Central

In this study, a comparative analysis of metal-related neuronal vulnerability was performed in two brainstem nuclei, the locus coeruleus (LC) and substantia nigra (SN), known targets of the etiological noxae in Parkinson's disease and related disorders. LC and SN pars compacta neurons both degenerate in Parkinson's disease and other Parkinsonisms; however, LC neurons are comparatively less affected and with a variable degree of involvement. In this study, iron, copper, and their major molecular forms like ferritins, ceruloplasmin, neuromelanin (NM), manganese-superoxide dismutase (SOD), and copper/zinc-SOD were measured in LC and SN of normal subjects at different ages. Iron content in LC was much lower than that in SN, and the ratio heavy-chain ferritin/iron in LC was higher than in the SN. The NM concentration was similar in LC and SN, but the iron content in NM of LC was much lower than SN. In both regions, heavy- and light-chain ferritins were present only in glia and were not detectable in neurons. These data suggest that in LC neurons, the iron mobilization and toxicity is lower than that in SN and is efficiently buffered by NM. The bigger damage occurring in SN could be related to the higher content of iron. Ferritins accomplish the same function of buffering iron in glial cells. Ceruloplasmin levels were similar in LC and SN, but copper was higher in LC. However, the copper content in NM of LC was higher than that of SN, indicating a higher copper mobilization in LC neurons. Manganese-SOD and copper/zinc-SOD had similar age trend in LC and SN. These results may explain at least one of the reasons underlying lower vulnerability of LC compared to SN in Parkinsonian syndromes.

Zecca, Luigi; Stroppolo, Antonella; Gatti, Alberto; Tampellini, Davide; Toscani, Marco; Gallorini, Mario; Giaveri, Giuseppe; Arosio, Paolo; Santambrogio, Paolo; Fariello, Ruggero G.; Karatekin, Erdem; Kleinman, Mark H.; Turro, Nicholas; Hornykiewicz, Oleh; Zucca, Fabio A.

2004-01-01

122

Arabidopsis Copper Transport Protein COPT2 Participates in the Cross Talk between Iron Deficiency Responses and Low-Phosphate Signaling1[C][W  

PubMed Central

Copper and iron are essential micronutrients for most living organisms because they participate as cofactors in biological processes, including respiration, photosynthesis, and oxidative stress protection. In many eukaryotic organisms, including yeast (Saccharomyces cerevisiae) and mammals, copper and iron homeostases are highly interconnected; yet, such interdependence is not well established in higher plants. Here, we propose that COPT2, a high-affinity copper transport protein, functions under copper and iron deficiencies in Arabidopsis (Arabidopsis thaliana). COPT2 is a plasma membrane protein that functions in copper acquisition and distribution. Characterization of the COPT2 expression pattern indicates a synergic response to copper and iron limitation in roots. We characterized a knockout of COPT2, copt2-1, that leads to increased resistance to simultaneous copper and iron deficiencies, measured as reduced leaf chlorosis and improved maintenance of the photosynthetic apparatus. We propose that COPT2 could play a dual role under iron deficiency. First, COPT2 participates in the attenuation of copper deficiency responses driven by iron limitation, possibly to minimize further iron consumption. Second, global expression analyses of copt2-1 versus wild-type Arabidopsis plants indicate that low-phosphate responses increase in the mutant. These results open up new biotechnological approaches to fight iron deficiency in crops.

Perea-Garcia, Ana; Garcia-Molina, Antoni; Andres-Colas, Nuria; Vera-Sirera, Francisco; Perez-Amador, Miguel A.; Puig, Sergi; Penarrubia, Lola

2013-01-01

123

Electrodeposition and Characterization of Nickel, Iron, Copper Thin Films and the Creation of Nanoporous Structures  

NASA Astrophysics Data System (ADS)

There has been much research in creating nanoporous platinum or gold thin films for catalysis, but there has not been as much work done with other, less noble metals. This research explored the deposition of nickel, iron, and copper ternary alloys using controlled potential electrolysis (CPE) and the selective removal of the copper with DC potential amperometry (DCPA) and linear sweep voltammetry (LSV) to create nanoporous structures. These structures have the advantage of increased surface area creating more efficient catalysts. All films were characterized before and after dealloying using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) for composition. The roughness of each of the films was characterized by the capacitance of the film, with higher capacitances indicating a higher electrochemical surface area.

Yarranton, Jonathan; Hampton, Jennifer

2013-03-01

124

Relationship between Paratuberculosis and the microelements Copper, Zinc, Iron, Selenium and Molybdenum in Beef Cattle  

PubMed Central

To study the deficiency of minerals and its relationship with Paratuberculosis, blood, serum, and fecal samples were obtained from 75 adult bovines without clinical symptoms of the disease and from two bovines with clinical symptoms of the disease, from two beef herds with a previous history of Paratuberculosis in the Province of Buenos Aires, Argentina. Serum samples were processed by ELISA and feces were cultured in Herrolds medium. Copper, zinc and iron in serum were quantified by spectrophotometry and selenium was measured by the activity of glutathione peroxidase. We also determined copper, zinc, iron and molybdenum concentrations in pastures and the concentration of sulfate in water. Mycobacterium avium subsp paratuberculosis (Map) was isolated from 17.3% of fecal samples of asymptomatic animals and from the fecal samples from the two animals with clinical symptoms. All the Map-positive animals were also ELISA-positive or suspect, and among them, 84.6% presented low or marginal values of selenium and 69.2% presented low or marginal values of copper. The two animals with clinical symptoms, and isolation of Map from feces and organs were selenium-deficient and had the lowest activity of glutathione peroxidase of all the animals from both herds. All the animals negative to Map in feces and negative to ELISA had normal values of Se, while 13.8% of animals with positive ELISA or suspect and culture negative presented low levels of Se. Half of the animals that were negative both for ELISA and culture in feces were deficient in copper but none of them presented low values of selenium. The content of molybdenum and iron in pasture was high, 2.5 ppm and 1.13 ppm in one herd and 2.5 ppm and 2.02 ppm in the other, respectively, whereas the copper:molybdenum ratio was 1.5 and 5.2, respectively. These results do not confirm an interaction between imbalances of the micronutrients and clinical Paratuberculosis, but show evidence of the relationship between selenium deficiencies in animals with Map infection and ELISA positive results.

Paolicchi, F.; Perea, J.; Cseh, S.; Morsella, C.

2013-01-01

125

Relationship between Paratuberculosis and the microelements Copper, Zinc, Iron, Selenium and Molybdenum in Beef Cattle.  

PubMed

To study the deficiency of minerals and its relationship with Paratuberculosis, blood, serum, and fecal samples were obtained from 75 adult bovines without clinical symptoms of the disease and from two bovines with clinical symptoms of the disease, from two beef herds with a previous history of Paratuberculosis in the Province of Buenos Aires, Argentina. Serum samples were processed by ELISA and feces were cultured in Herrolds medium. Copper, zinc and iron in serum were quantified by spectrophotometry and selenium was measured by the activity of glutathione peroxidase. We also determined copper, zinc, iron and molybdenum concentrations in pastures and the concentration of sulfate in water. Mycobacterium avium subsp paratuberculosis (Map) was isolated from 17.3% of fecal samples of asymptomatic animals and from the fecal samples from the two animals with clinical symptoms. All the Map-positive animals were also ELISA-positive or suspect, and among them, 84.6% presented low or marginal values of selenium and 69.2% presented low or marginal values of copper. The two animals with clinical symptoms, and isolation of Map from feces and organs were selenium-deficient and had the lowest activity of glutathione peroxidase of all the animals from both herds. All the animals negative to Map in feces and negative to ELISA had normal values of Se, while 13.8% of animals with positive ELISA or suspect and culture negative presented low levels of Se. Half of the animals that were negative both for ELISA and culture in feces were deficient in copper but none of them presented low values of selenium. The content of molybdenum and iron in pasture was high, 2.5 ppm and 1.13 ppm in one herd and 2.5 ppm and 2.02 ppm in the other, respectively, whereas the copper:molybdenum ratio was 1.5 and 5.2, respectively. These results do not confirm an interaction between imbalances of the micronutrients and clinical Paratuberculosis, but show evidence of the relationship between selenium deficiencies in animals with Map infection and ELISA positive results. PMID:24159298

Paolicchi, F; Perea, J; Cseh, S; Morsella, C

2013-01-01

126

Shock compression of highly porous samples of copper, iron, nickel and their equation of state  

SciTech Connect

Shock compressibility of copper, iron and nickel samples is studied whose initial density was 5-20 times less than the normal up to {approx}90 GPa pressures. The porous samples were produced from fine-grain powder with sizes of separate grains being several hundreds 0.2-0.3 nm. Explosive generators producing planar and spherical shock waves in the samples were used for the shock loading. The results found are compared with the computations with the semi-empirical equation of state of metals of a variable nuclei and electrons heat capacity.

Trunin, R. F.; Zhernokletov, M. V.; Simakov, G. V.; Gudarenko, L. F.; Gushchina, O. N. [Russian Federal Nuclear Center-VNIIEF, Sarov (Russian Federation)

1998-07-10

127

Optimal copper supply is required for normal plant iron deficiency responses.  

PubMed

Iron (Fe) and copper (Cu) homeostasis are tightly linked across biology. Understanding crosstalk between Fe and Cu nutrition could lead to strategies for improved growth on soils with low or excess metals, with implications for agriculture and phytoremediation. Here, we show that Cu and Fe nutrition interact to increase or decrease Fe and/or Cu accumulation in leaves and Fe uptake processes. Leaf Cu concentration increased under low Fe supply, while high Cu lowered leaf Fe concentration. Ferric reductase activity, an indicator of Fe demand, was inhibited at insufficient or high Cu supply. Surprisingly, plants grown without Fe were more susceptible to Cu toxicity. PMID:24084753

Waters, Brian M; Armbrust, Laura C

2013-12-01

128

Optimal copper supply is required for normal plant iron deficiency responses  

PubMed Central

Iron (Fe) and copper (Cu) homeostasis are tightly linked across biology. Understanding crosstalk between Fe and Cu nutrition could lead to strategies for improved growth on soils with low or excess metals, with implications for agriculture and phytoremediation. Here, we show that Cu and Fe nutrition interact to increase or decrease Fe and/or Cu accumulation in leaves and Fe uptake processes. Leaf Cu concentration increased under low Fe supply, while high Cu lowered leaf Fe concentration. Ferric reductase activity, an indicator of Fe demand, was inhibited at insufficient or high Cu supply. Surprisingly, plants grown without Fe were more susceptible to Cu toxicity.

Waters, Brian M; Armbrust, Laura C

2013-01-01

129

Effect of adsorbed chlorine and oxygen on the shear strength of iron and copper junctions  

NASA Technical Reports Server (NTRS)

Static-friction experiments were performed in ultrahigh vacuum at room temperature on copper, iron, and steel contacts selectively contaminated with oxygen and chlorine in submonolayer amounts. The concentration of the adsorbates was determined with Auger electron spectroscopy and was measured relative to the saturation concentration of oxygen on iron (concentration, 1.0). The coefficient of static friction decreased with increasing adsorbate concentration; however, it was independent of the type of metal and the adsorbate species. The results compared satisfactorily with an extension of the junction growth theory to heterogeneous interfaces. The reduction in interfacial shear strength was measured by the ratio of the shear strength of the interface with an adsorbate concentration of 1.0 and the strength of the clean metal interface. This ratio was about 0.835 for all the systems tested.

Wheeler, D. R.

1976-01-01

130

Effect of adsorbed chlorine and oxygen on shear strength of iron and copper junctions  

NASA Technical Reports Server (NTRS)

Static friction experiments were performed in ultrahigh vacuum at room temperature on copper, iron, and steel contacts selectively contaminated with oxygen and chlorine in submonolayer amounts. The concentration of the adsorbates was determined with Auger electron spectroscopy and was measured relative to the saturation concentration of oxygen on iron (concentration 1.0). The coefficient of static friction decreased with increasing adsorbate concentration. It was independent of the metal and the adsorbate. The results compared satisfactorily with an extension of the junction growth theory to heterogeneous interfaces. The reduction in interfacial shear strength was measured by the ratio sub a/sub m where sub a is the shear strength of the interface with an adsorbate concentration of 1.0, and sub m is the strength of the clean metal interface. This ratio was 0.835 + or - 0.012 for all the systems tested.

Wheeler, D. R.

1975-01-01

131

Nuclear magnetic resonance studies of the effect of vortices on the high temperature superconductor yttrium barium copper oxide  

NASA Astrophysics Data System (ADS)

Nuclear Magnetic Resonance in the material YBa2Cu3O 7 is strongly affected by the presence of magnetic vortices. The effects produced by the vortices can be used to gain knowledge about the physics of vortices and the physics of these materials. NMR nutation curves show that the vortices produce lossy (Ohmic) conduction in this material and greatly enhance the penetration depth over the London value. This enhancement is necessary to study crystal samples. The vortices induce supercurrents in the material which in turn enhance the density of states at the Fermi level. This enhancement, known as the Volovik Effect, can be observed in NMR as an increase in the spin-lattice relaxation rate as a function of frequency across the resonance line. The Volovik Effect was observed in both copper and oxygen in the plane of YBa2Cu3O7. The Volovik Effect was not able to be observed with sufficient precision to discriminate between various theories because it was obscured by other physical mechanisms within the sample studied.

Milling, Craig Thomas

132

Friction and transfer of copper, silver, and gold to iron in the presence of various adsorbed surface films  

NASA Technical Reports Server (NTRS)

Sliding friction experiments were conducted with the noble metals copper, silver, and gold and two binary alloys of these metals contacting iron in the presence of various adsorbates including, oxygen, methyl mercaptan, and methyl chloride. A pin on disk specimen configuration was used with a load of 100 grams, sliding velocity of 60 mm/min; at 25 C with the surfaces saturated with the adsorbates. Auger emission spectroscopy was used to monitor surface films. Results of the experiments indicate that friction and transfer characteristics are highly specific with respect to both the noble metal and surface film present. With all three metals and films transfer of the noble metal to iron occurred very rapidly. With all metals and films transfer of the noble metal to iron continuously increased with repeated passes except for silver and copper sliding on iron sulfide.

Buckley, D. H.

1979-01-01

133

Copper and iron concentrations in Ascophyllum nodosum (Fucales, Phaeophyta) from different sites in Ireland and after culture experiments in relation to thallus age and epiphytism  

Microsoft Academic Search

In laboratory experiments, copper concentrations in plants of Ascophyllum nodosum (L.) Le Jolis (Fucales, Phaeophyta) increased with the concentrations in the culture media and were highest in younger, meristematic thallus parts. After initial accumulation in high-copper medium and subsequent transfer to clean seawater for 5 days, no release of copper could be detected. Iron concentrations in A. nodosum tissue were

Dagmar B. Stengel; Matthew J. Dring

2000-01-01

134

The Proteome of Copper, Iron, Zinc, and Manganese Micronutrient Deficiency in Chlamydomonas reinhardtii*  

PubMed Central

Trace metals such as copper, iron, zinc, and manganese play important roles in several biochemical processes, including respiration and photosynthesis. Using a label-free, quantitative proteomics strategy (MSE), we examined the effect of deficiencies in these micronutrients on the soluble proteome of Chlamydomonas reinhardtii. We quantified >103 proteins with abundances within a dynamic range of 3 to 4 orders of magnitude and demonstrated statistically significant changes in ?200 proteins in each metal-deficient growth condition relative to nutrient-replete media. Through analysis of Pearson's coefficient, we also examined the correlation between protein abundance and transcript abundance (as determined via RNA-Seq analysis) and found moderate correlations under all nutritional states. Interestingly, in a subset of transcripts known to significantly change in abundance in metal-replete and metal-deficient conditions, the correlation to protein abundance is much stronger. Examples of new discoveries highlighted in this work include the accumulation of O2 labile, anaerobiosis-related enzymes (Hyd1, Pfr1, and Hcp2) in copper-deficient cells; co-variation of Cgl78/Ycf54 and coprogen oxidase; the loss of various stromal and lumenal photosynthesis-related proteins, including plastocyanin, in iron-limited cells; a large accumulation (from undetectable amounts to over 1,000 zmol/cell) of two COG0523 domain-containing proteins in zinc-deficient cells; and the preservation of photosynthesis proteins in manganese-deficient cells despite known losses in photosynthetic function in this condition.

Hsieh, Scott I.; Castruita, Madeli; Malasarn, Davin; Urzica, Eugen; Erde, Jonathan; Page, M. Dudley; Yamasaki, Hiroaki; Casero, David; Pellegrini, Matteo; Merchant, Sabeeha S.; Loo, Joseph A.

2013-01-01

135

The proteome of copper, iron, zinc, and manganese micronutrient deficiency in Chlamydomonas reinhardtii.  

PubMed

Trace metals such as copper, iron, zinc, and manganese play important roles in several biochemical processes, including respiration and photosynthesis. Using a label-free, quantitative proteomics strategy (MS(E)), we examined the effect of deficiencies in these micronutrients on the soluble proteome of Chlamydomonas reinhardtii. We quantified >10(3) proteins with abundances within a dynamic range of 3 to 4 orders of magnitude and demonstrated statistically significant changes in ~200 proteins in each metal-deficient growth condition relative to nutrient-replete media. Through analysis of Pearson's coefficient, we also examined the correlation between protein abundance and transcript abundance (as determined via RNA-Seq analysis) and found moderate correlations under all nutritional states. Interestingly, in a subset of transcripts known to significantly change in abundance in metal-replete and metal-deficient conditions, the correlation to protein abundance is much stronger. Examples of new discoveries highlighted in this work include the accumulation of O(2) labile, anaerobiosis-related enzymes (Hyd1, Pfr1, and Hcp2) in copper-deficient cells; co-variation of Cgl78/Ycf54 and coprogen oxidase; the loss of various stromal and lumenal photosynthesis-related proteins, including plastocyanin, in iron-limited cells; a large accumulation (from undetectable amounts to over 1,000 zmol/cell) of two COG0523 domain-containing proteins in zinc-deficient cells; and the preservation of photosynthesis proteins in manganese-deficient cells despite known losses in photosynthetic function in this condition. PMID:23065468

Hsieh, Scott I; Castruita, Madeli; Malasarn, Davin; Urzica, Eugen; Erde, Jonathan; Page, M Dudley; Yamasaki, Hiroaki; Casero, David; Pellegrini, Matteo; Merchant, Sabeeha S; Loo, Joseph A

2013-01-01

136

Synergetic effects of mixed copper-iron oxides oxygen carriers in chemical looping combustion  

SciTech Connect

Chemical looping combustion (CLC) is an emerging technology for clean energy production from fuels. CLC produces sequestration-ready CO{sub 2}-streams without a significant energy penalty. Development of efficient oxygen carriers is essential to successfully operate a CLC system. Copper and iron oxides are promising candidates for CLC. Copper oxide possesses high reactivity but it has issues with particle agglomeration due to its low melting point. Even though iron oxide is an inexpensive oxygen carrier it has a slower reactivity. In this study, mixed metal oxide carriers containing iron and copper oxides were evaluated for coal and methane CLC. The components of CuO and Fe{sub 2}O{sub 3} were optimized to obtain good reactivity while maintaining physical and chemical stability during cyclic reactions for methane-CLC and solid-fuel CLC. Compared with single metal oxygen carriers, the optimized Cu–Fe mixed oxide oxygen carriers demonstrated high reaction rate, better combustion conversion, greater oxygen usage and improved physical stability. Thermodynamic calculations, XRD, TGA, flow reactor studies and TPR experiments suggested that there is a strong interaction between CuO and Fe{sub 2}O{sub 3} contributing to a synergistic effect during CLC reactions. The amount of oxygen release of the mixed oxide carrier in the absence of a fuel was similar to that of the single metal oxides. However, in the presence of fuels, the oxygen consumption and the reaction profiles of the mixed oxide carriers were significantly better than that of the single metal oxides. The nature of the fuel not only influenced the reactivity, but also the final reduction status of the oxygen carriers during chemical looping combustion. Cu oxide of the mixed oxide was fully reduced metallic copper with both coal and methane. Fe oxide of the mixed oxide was fully reduced Fe metal with methane but it was reduced to only FeO with coal. Possible mechanisms of how the presence of CuO enhances the reduction of Fe{sub 2}O{sub 3} are discussed.

Siriwardane, Ranjani; Tian, Hanjing; Simonyi, Thomas; Poston, James

2013-06-01

137

Unique tetranuclear copper(II) cluster and monomeric iron(II), (III) complexes with a tris(imidazolyl) chelating ligand  

Microsoft Academic Search

Copper(II) and iron(II, III) complexes of the tripodal ligand, tris(1-methyl-1H-imidazol-2-yl)methanol (Htmim), have been synthesized and characterized by elemental analysis, 1H NMR and IR spectroscopies, magnetic moment measurement and X-ray crystallography. The structure of the copper complex, [Cu4(tmim)4(CF3SO3)2](CF3SO3)2·2MeOH (1), can be regarded as a polyimidazole-linked tetranuclear cluster where each copper atom adopts a five-coordinate square-pyramidal geometry ligated by the tmim anion.

Liang Ping Wu; Yoshiro Yamagiwa; Ichirou Ino; Kunihisa Sugimoto; Takayoshi Kuroda-Sowa; Tadao Kamikawa; Megumu Munakata

1999-01-01

138

The chemical speciation of dissolved nickel, copper, vanadium and iron in Liverpool Bay, Irish Sea  

NASA Astrophysics Data System (ADS)

CSV (cathodic stripping voltammetry) was used to determine dissolved nickel, copper, vanadium and iron in seawater samples collected from Liverpool Bay (Irish Sea). It is shown that the concentrations of the free metal ion and of the metal organic complexes can be calculated from the CSV-labile and total dissolved metal concentrations. The labile fraction consists of the inorganically complexed metal ions, and a certain proportion of the natural organic-metal complexes which depends on the relative stability of the metal complexes formed with the added chelator and with the natural organic ligands. Total dissolved metal concentrations were obtained after UV-photolysis of acidified samples. Results from two surveys, carried out during May and September 1985, clearly identified the River Mersey as being a significant contributor of both nickel and copper to Liverpool Bay. The dumping of sewage sludge produced elevated localized concentrations for colloidal nickel. Considerable proportions of nickel (31-41%) were found to occur as stable organic compounds, whereas almost all copper (98-99%) occurred in less stable organic complexes. A smaller proportion of iron (18%) was found to be bound by dissolved organic material. Organic complexation was generally greater in September than in May, which is illustrated by the mean log ?CuL values being higher in September (2·72) than in May (2·39). The absence of a relationship between organic complexation and the concentration of organic fluorescent material suggests that this material is not a major component of the organic metal complexing material in shelf waters.

Nimmo, M.; van den Berg, C. M. G.; Brown, J.

1989-07-01

139

Association of serum levels of iron, copper, and zinc, and inflammatory markers with bacteriological sputum conversion during tuberculosis treatment.  

PubMed

Iron, copper, and zinc are key micronutrients that play an important role in the immune response to Mycobacterium tuberculosis. The present study aimed to evaluate the association between serum levels of those micronutrients, inflammatory markers, and the smear and culture conversion of M. tuberculosis during 60 days of tuberculosis treatment. Seventy-five male patients with pulmonary tuberculosis (mean age, 40.0?±?10.7 years) were evaluated at baseline and again at 30 and 60 days of tuberculosis treatment. Serum levels of iron, copper, zinc, albumin, globulin, C-reactive protein, and hemoglobin, and smear and cultures for M. tuberculosis in sputum samples were analyzed. Compared to healthy subjects, at baseline, patients with PTB had lower serum iron levels, higher copper levels and copper/zinc ratio, and similar zinc levels. During the tuberculosis treatment, no significant changes in the serum levels of iron, zinc, and copper/zinc were observed. Lower serum copper levels were associated with bacteriological conversion in tuberculosis treatment (tuberculosis-negative) at 30 days but not at 60 days (tuberculosis-positive). C-reactive protein levels and the C-reactive protein/albumin ratio were lower in tuberculosis-negative patients than in tuberculosis-positive patients at 30 and 60 days after treatment. Albumin and hemoglobin levels and the albumin/globulin ratio in patients with pulmonary tuberculosis increased during the study period, regardless of the bacteriological results. High serum globulin levels did not change among pulmonary tuberculosis patients during the study. Serum copper levels and the C-reactive protein/albumin ratio may be important parameters to evaluate the persistence of non-conversion after 60 days of tuberculosis treatment, and they may serve as predictors for relapse after successful treatment. PMID:24958018

Moraes, Milena Lima de; Ramalho, Daniela Maria de Paula; Delogo, Karina Neves; Miranda, Pryscila Fernandes Campino; Mesquita, Eliene Denites Duarte; de Melo Guedes de Oliveira, Hedi Marinho; Netto, Antônio Ruffino; Dos Anjos, Marcelino José; Kritski, Afrânio Lineu; de Oliveira, Martha Maria

2014-08-01

140

Comparative study of serum zinc, copper, manganese, and iron in preeclamptic pregnant women.  

PubMed

Preeclampsia complicates 2-8 % of all pregnancies and it is one of the leading causes of maternal mortality and pre-term delivery in the world. Unfortunately, there is scarcity of document discussing the circulating level of several essential trace elements in preeclampsia patients in Bangladesh. The present study was designed to evaluate the serum concentration of four trace elements, namely zinc, copper, manganese, and iron, in preeclamptic pregnant women. The study was conducted as a case-control study with 50 preeclamptic pregnant women as cases and 58 normotensive pregnant women as controls. Obstetric, anthropometric, and clinical data were collected at routine obstetric visits. Serum trace elements were determined by flame atomic absorption spectroscopy. Independent sample t test and Pearson's correlation test were done for the statistical analysis using the statistical software package SPSS, version 16.0 (SPSS Inc., Chicago, IL). We observed significant differences for gestational age, body mass index, and systolic and diastolic blood pressure between patient and control groups (p??0.05) except the correlation between zinc and iron in preeclampsia patients (p?copper, manganese, and iron compared to the healthy pregnant women. PMID:23749478

Sarwar, Md Shahid; Ahmed, Salma; Ullah, Mohd Shahid; Kabir, Humayun; Rahman, G K M Mustafizur; Hasnat, Abul; Islam, Mohammad Safiqul

2013-07-01

141

Manufactures and Characterizations of Photodiode Thin Film Barium Strontium Titanate (BST) Doped by Niobium and Iron as Light Sensor  

NASA Astrophysics Data System (ADS)

Pure Ba0,5Sr0,5TiO3 (BST) thin film, BST doped by niobium (BNST) and BST doped by iron (BFST) have been synthesized on p-type Si (100) substrates using Chemical Solution Deposition (CSD) methods followed by spin coating and annealing techniques. Current-voltage characterizations on these sample result in agreement that all of the BST, BNST, and BFST thin films have photodiode properties. Electrical conductivity values of BST, BNST, and BFST are in the range of conductivity values of semiconductor materials. Niobium or iron doping on the BST samples increase their conductivity value their dielectric constant. This conductivity values may change when a light is exposed on the film surface. Absorbance and reflectance characterizations show that the BST, BNST, and BFST thin films absorb certain range of visible and infrared light. It is convincing that the BST, BNST, and BFST thin films might be used as photodiode light sensor.

Dahrul, Muhammad; Syafutra, Heriyanto; Arif, Ardian; Irzaman; Indro, Muhammad Nur; Siswadi

2010-12-01

142

Application of cooperative iron/copper catalysis to a palladium-free borylation of aryl bromides with pinacolborane.  

PubMed

A new cooperative copper/iron catalysis for the borylation of various aryl bromides with pinacolborane, at -10 °C, is reported. Use of the toxic, precious metal Pd is avoided. The mechanism of the protodebromination side reaction is discussed. PMID:24738740

Labre, Flavien; Gimbert, Yves; Bannwarth, Pierre; Olivero, Sandra; Duñach, Elisabet; Chavant, Pierre Y

2014-05-01

143

Solid-phase extraction of copper, iron and zinc ions on Bacillus thuringiensis israelensis loaded on Dowex optipore V-493.  

PubMed

Bacillus thuringiensis israelensis loaded on Dowex optipore V-493 as new adsorbent for the separation-preconcentration of heavy metal ions has been proposed. The analytical conditions for the quantitative recoveries of copper(II), iron(III) and zinc(II) including pH, amounts of adsorbent, sample volume, etc. were investigated. The influences of alkaline and earth alkaline ions were also reported. The recovery values for the analytes are generally higher than 95%. The preconcentration factor was 37. The limit of detections of the analyte ions (k=3, N=21) were 1.14 microgL(-1) for copper, 2.01 microgL(-1) for iron and 0.14 microgL(-1) for zinc. The relative standard deviations of the determinations were found to be lower than 9%. The procedure was validated by analyzing copper, iron and zinc contents in two certified reference materials, NRCC-SLRS-4 Riverine water and NIST SRM 1515 Apple leaves. Agreements between the obtained results and the certified values were achieved. The developed preconcentration method was applied in the flame atomic absorption spectrometric determination of copper, iron and zinc in several samples including a multivitamin-multimineral tablet, dialysis solutions, natural waters and some food samples. PMID:18359563

Tuzen, Mustafa; Melek, Esra; Soylak, Mustafa

2008-11-30

144

Chelating of iron and copper alters properties of DNA in L5178Y cells, as revealed by the comet assay.  

PubMed

We have previously found different proportions of iron and copper in nuclei of two sublines of murine lymphoma L5178Y (LY) and proposed a model of chromatin organization with these metal ions at the DNA attachment sites. We now examine the effect of chelators, desferal (DFO, iron-specific) and neocupreine (NEO, copper-specific) on DNA of LY-R and LY-S cells, using the comet and micronuclei frequency tests. There is less copper and more iron in LY-R nuclei than in LY-S nuclei. Accordingly, the effect of NEO is more marked in LY-R than in LY-S cells and in both sublines it is expressed as enhanced tail moment (measure of DNA damage in the comet assay) and increased micronuclei frequency. On the contrary, the effect of DFO on the tail moment is less pronounced in LY-R than in LY-S cells. With increasing DFO concentrations, there is a gradual decrease in the tail moment values below the control level in LY-S cells. In LY-R cells the tail moment values initially increase, then gradually decrease, eventually falling below the control level. This points to a dramatic conformational change that masks the effect of DNA discontinuities. The presence of the latter is indicated by the increase in micronuclei frequency. These results support the postulated differential role of iron and copper ions in maintaining the higher order DNA structure in LY sublines. PMID:10377948

Kruszewski, M; Iwane?ko, T; Bouzyk, E; Szumiel, I

1999-05-14

145

Structure of self-interstitial atom clusters in iron and copper  

NASA Astrophysics Data System (ADS)

The dislocation core structure of self-interstitial atom (SIA) clusters in bcc iron and fcc copper is determined using the hybrid ab initio continuum method of Banerjee [Philos. Mag. 87, 4131 (2007)]. To reduce reliance on empirical potentials and to facilitate predictions of the effects of local chemistry and stress on the structure of defects, we present here a hybrid extension of the Peierls-Nabarro continuum model, with lattice resistance to slip determined separately from ab initio calculations. A method is developed to reconstruct atomic arrangements and geometry of SIA clusters from the hybrid model. The results are shown to compare well with molecular-dynamics simulations. In iron, the core structure does not show dependence on the size of the self-interstitial cluster, and is nearly identical to that of a straight edge dislocation. However, the core structure of SIA clusters in Cu is shown to depend strongly on the cluster size. Small SIA clusters are found to have nondissociated compact dislocation cores, with a strong merging of Shockley partial dislocations and a relatively narrow stacking fault (SF) region. The compact nature of the SIA core in copper is attributed to the strong dependence of the self-energy on the cluster size. As the number of atoms in the SIA cluster increases, Shockley partial dislocations separate and the SF region widens, rendering the SIA core structure to that of an edge dislocation. The separation distance between the two partials widens as the cluster size increases, and tends to the value of a straight edge dislocation for cluster sizes above 400 atoms. The local stress is found to have a significant effect on the atomic arrangements within SIA clusters in copper and the width of the stacking faults. An applied external shear can delocalize the core of an SIA cluster in copper, with positive shear defined to be on the (111) plane along the [1¯1¯2] direction. For an SIA cluster containing 1600 atoms, a positive 1 GPa shear stress delocalizes the cluster and expands the SF to 30b , while a negative shear stress of 2 GPa contracts the core to less than 5b , where b is the Burgers vector magnitude.

Takahashi, Akiyuki; Ghoniem, Nasr M.

2009-11-01

146

Rapid chemical synthesis of the barium ferrate super-iron Fe (VI) compound, BaFeO 4  

NASA Astrophysics Data System (ADS)

An alternate rapid synthesis of BaFeO 4 is demonstrated. Fe(VI) salts, including BaFeO 4, are energetic cathode materials in super-iron batteries ranging from primary to secondary, and including aqueous and non-aqueous cells. Of the Fe(VI) salts, BaFeO 4 sustains unusually facile charge transfer, of importance to the high power domain of alkaline batteries. Unlike previous syntheses, BaFeO 4 preparation is demonstrated from all solid state room temperature reactants. This eliminates several synthetic procedural steps and improves stability to approach that of the rigorously stable chemically synthesized K 2FeO 4 salt.

Licht, Stuart; Naschitz, Vera; Wang, Baohui

147

ESR of copper and iron complexes with antitumor and cytotoxic properties.  

PubMed Central

The relatively few iron and copper metal complexes which have been examined in cells and tissues for their redox properties, radical generation properties, and antitumor activity are discussed for studies which utilized electron spin resonance spectroscopy (ESR). A common property of a number of metal complexes, which include bleomycin, adriamycin, and thiosemicarbazones described in this review, is that they are readily reduced by thiol compounds and oxidized by oxygen or reduced species of oxygen to produce radicals. Structural features of these reactions are identified by ESR spectroscopy in model systems and often in cells. Furthermore, ESR spectroscopy has been most useful to probe the environment of the complexes in cells and to measure the rate of reduction of their oxidized forms. As a result of these studies, it is anticipated that more attention will be given to the exploration of redox-active metal complexes as drugs.

Antholine, W E; Kalyanaraman, B; Petering, D H

1985-01-01

148

ESR of copper and iron complexes with antitumor and cytotoxic properties  

SciTech Connect

The relatively few iron and copper metal complexes which have been examined in cells and tissues for their redox properties, radical generation properties, and antitumor activity are discussed for studies which utilized electron spin resonance spectroscopy (ESR). A common property of a number of metal complexes, which include bleomycin, adriamycin, and thiosemicarbazones described in this review, is that they are readily reduced by thiol compounds and oxidized by oxygen or reduced species of oxygen to produce radicals. Structural features of these reactions are identified by ESR spectroscopy in model systems and often in cells. Furthermore, ESR spectroscopy has been most useful to probe the environment of the complexes in cells and to measure the rate of reduction of their oxidized forms. As a result of these studies, it is anticipated that more attention will be given to the exploration of redox-active metal complexes as drugs. 95 references.

Antholine, W.E.; Kalyanaraman, B.; Petering, D.H.

1985-12-01

149

Some observations on the interaction of zinc, copper, and iron metabolism in lead and cadmium toxicity.  

PubMed Central

A brief review of the literature indicates that nutritional deficiencies have been shown to increase the absorption and toxicity of orally ingested lead and cadmium. Results from recent studies indicates that low level oral ingestion of cadmium and lead perturbs the metabolism of zinc, copper, and iron and that these changes may be the earliest manifestation of the toxicity of lead and cadmium. The significance of these findings reveals itself in two ways: namely, that toxicologic investigations of lead and cadmium, whether experimental or clinical, must be based on a definitive consideration of the nutritional status of animals or people, and, secondly, that the preventive role of nutrition, especially that of trace metal intakes, must be taken seriously when establishing measures for reducing, eliminating, or combatting the toxic effects of widespread exposure to lead and cadmium in humans.

Petering, H G

1978-01-01

150

Electronic band structure and optical absorption of nanotubular zinc oxide doped with Iron, Cobalt, or Copper  

NASA Astrophysics Data System (ADS)

The absorption spectra of the precursor-derived solid solutions Zn1 - x M x O ( M = Fe, Co, Cu) with a tubular morphology of aggregates have been investigated in the ultraviolet and visible regions. The maximum metal concentration x in the Zn1 - x M x O solid solutions is 0.075 for iron, 0.2 for cobalt, and 0.1 for copper. It has been found that the optical absorption and the band gap of the Zn1 - x M x O compounds depend on the type of dopant. The obtained experimental data have been interpreted using the results of the performed ab initio calculations of the electronic band structure and optical absorption.

Zhukov, V. P.; Krasil'nikov, V. N.; Perelyaeva, L. A.; Baklanova, I. V.; Shein, I. R.

2013-12-01

151

Structure and properties of clusters of self-interstitial atoms in fcc copper and bcc iron  

NASA Astrophysics Data System (ADS)

Static and molecular dynamics simulations have been used with different types of interatomic potentials to investigate the structure, properties and stability of self-interstitial atom (SIA) clusters produced during irradiation. In f-iron (Fe), faulted clusters of <110> dumbbells are unstable for all the potentials. The most stable SIA clusters are sets of parallel <111> crowdions. Large clusters of this type form perfect dislocation loops with Burgers vector b = ½<111>. Small clusters (less than 9 SIAs) of <100> crowdions are stable at 0 K, but transform into a set of <111> crowdions on annealing. Larger <100> clusters are stable and form perfect dislocation loops with b = <100>. Both types of loops are glissile. In copper (Cu), clusters of parallel <100> dumbbells and <110> crowdions are stable. Large clusters of these types form faulted and perfect dislocation loops with b = 1/3<111> and ½<110> respectively. Small faulted clusters (less than 7 SIAs) of irregular shape can transform into a set of <110> crowdions during annealing. Larger faulted clusters are stable as hexagonal 1/3<111> Frank loops at temperatures of about up to 1050 K for a period of several hundred picoseconds. All faulted clusters are sessile. Clusters of <110> crowdions and ½<110> perfect loops are glissile and stable at all temperatures. When large enough (more than 49-64 SIAs) they can dissociate on their glide prism. Symmetric three-dimensional clusters of <100> dumbbells are stable at 0 K but during annealing they transform into sets of <110> crowdions. The results for both iron and copper are discussed and compared with experimental data and provide a basis for investigating and explaining the observed differences in radiation damage accumulation behaviour between fcc and bcc metals.

Osetsky, Yu. N.; Serra, A.; Singh, B. N.; Golubov, S. I.

2000-09-01

152

Three histidine residues of amyloid-beta peptide control the redox activity of copper and iron.  

PubMed

Zinc, iron and copper are concentrated in senile plaques of Alzheimer disease. Copper and iron catalyze the Fenton-Haber-Weiss reaction, which likely contributes to oxidative stress in neuronal cells. In this study, we found that ascorbate oxidase activity and the intensity of ascorbate radicals measured using ESR spectroscopy, generated by free Cu(II), was decreased in the presence of amyloid-beta (Abeta), the major component of senile plaques. Specifically, the ascorbate oxidase activity was strongly inhibited (85% decrease) in the presence of Abeta1-16 or Abeta1-42, whereas it was only slightly inhibited in the presence of Abeta1-12 or Abeta25-35 (<20% inhibition). Ascorbate-dependent hydroxyl radical generation by free Cu(II) decreased in the presence of Abeta in the identical order of Abeta1-42, Abeta1-16 > Abeta1-12 and was abolished in the presence of 2-fold molar excess glycylhystidyllysine (GHK). Ascorbate oxidase activity and ascorbate-dependent hydroxyl radical generation by free Fe(III) were inhibited by Abeta1-42, Abeta1-16, and Abeta1-12. Although Cu(II)-Abeta shows a significant SOD-like activity, the rate constant for the reaction of superoxide with Cu(II)-Abeta was much slower than that with SOD. Overall, our results suggest that His6, His13, and His14 residues of Abeta1-42 control the redox activity of transition metals present in senile plaques. PMID:17929832

Nakamura, M; Shishido, N; Nunomura, Akihiko; Smith, Mark A; Perry, George; Hayashi, Y; Nakayama, K; Hayashi, T

2007-11-01

153

COPPER  

EPA Science Inventory

The report is a review of current knowledge of the distribution of copper in the environment and living things. Metabolism and the effects of copper in the biosphere are also considered. Copper compounds are common and widely distributed in nature. They are also extensively mined...

154

Regulation of Brain Iron and Copper Homeostasis by Brain Barrier Systems: Implication in Neurodegenerative Diseases  

PubMed Central

Iron (Fe) and copper (Cu) are essential to neuronal function; excess or deficiency of either is known to underlie the pathoetiology of several commonly known neurodegenerative disorders. This delicate balance of Fe and Cu in the central milieu is maintained by the brain barrier systems, i.e., the blood-brain barrier (BBB) between the blood and brain interstitial fluid and the blood- cerebrospinal fluid barrier (BCB) between the blood and cerebrospinal fluid (CSF). This review provides a concise description on the structural and functional characteristics of the brain barrier systems. Current understanding of Fe and Cu transport across the brain barriers is thoroughly examined, with major focuses on whether the BBB and BCB coordinate the direction of Fe and Cu fluxes between the blood and brain/CSF. In particular, the mechanism by which pertinent metal transporters in the barriers, such as the transferrin receptor (TfR), divalent metal transporter (DMT1), copper transporter (CTR1), ATP7A/B, and ferroportin (FPN), regulate metal movement across the barriers is explored. Finally, the detrimental consequences of dysfunctional metal transport by brain barriers, as a result of endogenous disorders or exogenous insults, are discussed. Understanding the regulation of Fe and Cu homeostasis in the central nervous system aids in the design of new drugs targeted on the regulatory proteins at the brain barriers for the treatment of metal’s deficiency or overload-related neurological diseases.

Zheng, Wei; Monnot, Andrew D.

2011-01-01

155

Evidence for iron, copper and zinc complexation as multinuclear sulphide clusters in oxic rivers  

PubMed

The availability and toxicity of trace metals in fresh water are known to be regulated by the complexation of free metal ions with dissolved organic matter. The potential role of inorganic sulphides in binding trace metals has been largely ignored because of the reduced persistence of sulphides in these oxic waters. However, nanomolar concentrations of copper and zinc sulphides have been observed in four rivers in Connecticut and Maryland. Here we report dissolved (< 0.2 microm particle diameter) sulphide concentrations ranging up to 600 nM, with more than 90% being complexed by copper, iron and zinc. These complexes account for up to 20% of the total dissolved Fe and Zn and 45% of the total dissolved Cu. Fourier transform mass spectrometry reveals that these complexes are not simple M(HS)+ protonated species but are higher-order unprotonated clusters (M3S3, M4S6, M2S4), similar to those found in laboratory solutions and bio-inorganic molecules. These extended structures have high stability constants and are resistant to oxidation and dissociation, which may help control the toxicity of these and other less abundant, but more toxic, trace metals, such as silver, cadmium and mercury. PMID:10972287

Rozan; Lassman; Ridge; Luther

2000-08-24

156

The Homeostasis of Iron, Copper, and Zinc in Paracoccidioides Brasiliensis, Cryptococcus Neoformans Var. Grubii, and Cryptococcus Gattii: A Comparative Analysis  

PubMed Central

Iron, copper, and zinc are essential for all living organisms. Moreover, the homeostasis of these metals is vital to microorganisms during pathogenic interactions with a host. Most pathogens have developed specific mechanisms for the uptake of micronutrients from their hosts in order to counteract the low availability of essential ions in infected tissues. We report here an analysis of genes potentially involved in iron, copper, and zinc uptake and homeostasis in the fungal pathogens Paracoccidioides brasiliensis, Cryptococcus neoformans var. grubii, and Cryptococcus gattii. Although prior studies have identified certain aspects of metal regulation in Cryptococcus species, little is known regarding the regulation of these elements in P. brasiliensis. We also present amino acid sequences analyses of deduced proteins in order to examine possible conserved domains. The genomic data reveals, for the first time, genes associated to iron, copper, and zinc assimilation and homeostasis in P. brasiliensis. Furthermore, analyses of the three fungal species identified homologs to genes associated with high-affinity uptake systems, vacuolar and mitochondrial iron storage, copper uptake and reduction, and zinc assimilation. However, homologs to genes involved in siderophore production were only found in P. brasiliensis. Interestingly, in silico analysis of the genomes of P. brasiliensis Pb01, Pb03, and Pb18 revealed significant differences in the presence and/or number of genes involved in metal homeostasis, such as in genes related to iron reduction and oxidation. The broad analyses of the genomes of P. brasiliensis, C. neoformans var. grubii, and C. gattii for genes involved in metal homeostasis provide important groundwork for numerous interesting future areas of investigation that are required in order to validate and explore the function of the identified genes and gene pathways.

Silva, Mirelle Garcia; Schrank, Augusto; Bailao, Elisa Flavia L.C.; Bailao, Alexandre Melo; Borges, Clayton Luiz; Staats, Charley Christian; Parente, Juliana Alves; Pereira, Maristela; Salem-Izacc, Silvia Maria; Mendes-Giannini, Maria Jose Soares; Oliveira, Rosely Maria Zancope; Silva, Livia Kmetzsch Rosa e; Nosanchuk, Joshua D.; Vainstein, Marilene Henning; de Almeida Soares, Celia Maria

2011-01-01

157

Effects of rutin supplementation on antioxidant status and iron, copper, and zinc contents in mouse liver and brain  

Microsoft Academic Search

The effect of rutin on total antioxidant status as well as on trace elements such as iron, copper, and zinc in mouse liver\\u000a and brain were studied. Mice were administrated with 0.75 g\\/kg or 2.25 g\\/kg P. O. of rutin for 30 d consecutively. Following\\u000a the treatment, the activity of total antioxidant status, catalase, Cu,Zn-superoxide dismutase, Mn-superoxide dismutase, zinc,\\u000a copper,

Zhonghong Gao; Huibi Xu; Kaixun Huang

2002-01-01

158

Domain Wall Pinning in the Iron-Rich Iron-Gold and Iron-Copper Binary Alloys  

NASA Astrophysics Data System (ADS)

Specimens of alpha-phase (b.c.c.) solid-solutions of iron-rich FeAu (1.10 at % Au) and FeCu (1.07 at % Cu) were thermally aged at 700 ^circC for different time durations. Precipitation and growth of the secondary phase epsilon Au (f.c.c.) and epsilonCu (f.c.c.) took place in the FeAu and FeCu alloys respectively, during the heat treatment. The specimens were polished and then studied under a transmission electron microscope. The size, density and shape of the precipitates were determined for different aging conditions. The knowledge of these parameters are fitted to a recent theory of strong and weak domain wall pinning by a random array of inhomogeneities, which allows values of the coercive field H_ {c}, to be predicted. Critical comparison between the observed and the calculated coercive fields were then made. A pinning index beta^ ' was derived and used to characterize the pinning behavior of the specimens. When beta ^' is close to or larger than 1, the pinning is definitely strong, else the pinning is weak. Based on the strong and weak pinning models, the relationships between the a.c. susceptibility chi_{a.c.}, and the effective bias field H, are derived for ferromagnets with random inhomogeneities. It is found that when H is less than H_{c}, chi_{a.c.} remains independent of H. When H is larger than H_{c}, chi_{a.c.} is proportional to H^{-1/2} (or H ^{-3/7} if demagnetizing effect due to the unpaired spins on the surface of the bowed wall is considered) and H^{-1} for strong and weak pinning respectively. A phase-locked magnetometer was employed to measure the a.c. susceptibilities of the FeAu and FeCu specimens after different durations of aging, as a function of bias field. The data were refined and analysed under the light of the newly developed relationships. The pinning regime of the specimens were then determined. Expressions for the fluctuation field, S _{v}, (a function of the magnetic viscosity coefficient) for the pinning models were derived. The relationships between coercive field and the activation volume of the domain wall in the two pinning models were also deduced. The activation volume were calculated for each case and were put into the appropriate S_ {v} expression for the S_ {v} values to be determined. The results were studied and compared with the works done by Wohlfarth and Barbier. The results obtained from these investigations converge toward a single conclusion. The pinning regime in the as-quenched FeAu specimen (zero age) and the low -age FeCu specimens is weak. For the prolonged age specimens of FeAu and FeCu, strong pinning is active. This claim was verified by the electron microscopic studies of the magnetic features and microstructure in these specimens by using Lorentz microscopic techniques.

Ng, Dickon H. L.

1989-12-01

159

Use of 3-hydroxy-1,3-diphenyltriazine in the spectrophotometric determination of copper, palladium, iron, cobalt, nickel, and molybdenum.  

PubMed

3-Hydroxy-1,3-diphenyltriazine (HDPTA) forms brightly coloured complexes with copper, palladium, iron, cobalt and nickel ions, which are readily extractable in benzene. The deep yellow molybdenum complex is completely soluble in 60% ethanol. All the chelates have a definite absorption maximum between 398 and 422 nm, the reagent absorption being negligible above 415 nm. The molar composition of the chelates is ML(2), except for iron and cobalt which form ML(3) complexes. Microquantities of these metals can be determined spectrophotometrically with HDPTA. PMID:18960697

Das, B; Shome, S C

1970-01-01

160

Self-organization of iron-atom nanostructures in the first layer of the (100) copper surface  

NASA Astrophysics Data System (ADS)

Mechanisms of the diffusion of surface vacancies and iron atoms in the first layer of the Cu(100) surface have been studied by molecular dynamics and the kinetic Monte Carlo method. The diffusion of embedded atoms results in the self-organization of bound iron-atom nanostructures. The time dependences of the number of most widespread nanostructures have been obtained. According to the results, the self-organization of embedded nanostructures can be divided into three stages in which the copper surface has significantly different morphologies.

Kolesnikov, S. V.

2014-05-01

161

Copper mobility in the Eastern Creek Volcanics, Mount Isa, Australia: evidence from laser ablation ICP-MS of iron-titanium oxides  

Microsoft Academic Search

The Palaeoproterozoic Eastern Creek Volcanics are a series of copper-rich tholeiitic basalts which occur adjacent to the giant sediment-hosted Mount Isa copper deposit in Queensland, Australia. The volcanic rocks are often cited as the source of metals for the deposit. New laser ablation ICP-MS analyses of iron–titanium oxides from the basalts provide evidence for the local mobilisation of copper during

Melissa J. Gregory

2006-01-01

162

Copper mobility in the Eastern Creek Volcanics, Mount Isa, Australia: evidence from laser ablation ICP-MS of iron-titanium oxides  

Microsoft Academic Search

The Palaeoproterozoic Eastern Creek Volcanics are a series of copper-rich tholeiitic basalts which occur adjacent to the giant sediment-hosted Mount Isa copper deposit in Queensland, Australia. The volcanic rocks are often cited as the source of metals for the deposit. New laser ablation ICP-MS analyses of iron-titanium oxides from the basalts provide evidence for the local mobilisation of copper during

Melissa J. Gregory

2006-01-01

163

Catalytic activity of systems based on coordination cyanides of copper, iron, ruthenium, and osmium in the reaction of ammonia synthesis  

Microsoft Academic Search

The purpose of the present investigation was to study the catalytic activity of systems based on cyano complexes of iron and its electronic analogs (ruthenium and osmium), and on coordination copper cyanides of the composition KâFe(Cu(CN)â)â and KFe(Cu(CN)â). The catalyst activities under 200 atm pressure were determined in an apparatus at space velocity of 15,000 h⁻¹ in the temperature range

Zh. I. Tkachenko; L. I. Pavlenko; Yu. A. Lyubchenko

1980-01-01

164

Limited effects of combined dietary copper deficiency\\/iron overload on oxidative stress parameters in rat liver and plasma  

Microsoft Academic Search

Copper (Cu) deficiency decreases the activity of Cu-dependent antioxidant enzymes such as Cu,zinc-superoxide dismutase (Cu,Zn-SOD) and may be associated with increased susceptibility to oxidative stress. Iron (Fe) overload represents a dietary oxidative stress relevant to overuse of Fe-containing supplements and to hereditary hemochromatosis. In a study to investigate oxidative stress interactions of dietary Cu deficiency with Fe overload, weanling male

Kevin A. Cockell; Andrew T. L. Wotherspoon; Bartholomeus Belonje; Melissa E. Fritz; René Madère; Nick Hidiroglou; Louise J. Plouffe; W. M. Nimal Ratnayake; Stan Kubow

2005-01-01

165

Impact of selenium, iron, copper and zinc in on\\/off Parkinson’s patients on L-dopa therapy  

Microsoft Academic Search

We have quantitated CSF and serum levels of Selenium, iron, copper and zinc by Atomic absorption spectrophotometer in 36 patients\\u000a with parkinson’s disease all on L-dopa therapy. Out of these 19 showed on or positive response to L-dopa where as 21 patients\\u000a showed on and off response. These data were compared with 21 healthy controls. The results showed that serum

G. A. Qureshi; A. A. Qureshi; S. A. Memon; S. H. Parvez

166

Total and Suspended Cadmium, Cobalt, Copper, Iron, Lead, Manganese, Nickel, and Zinc in the Water Column of the Black Sea  

Microsoft Academic Search

\\u000a The trace metals cadmium, cobalt, copper, iron, manganese, nickel, lead and zinc were determined at eleven different stations\\u000a in the Black Sea, in November 1984. Sampling from the surface down to 2100 m was carried out. Suspended matter was collected\\u000a and analysed. It was found that elements which form strong sulphide complexes show significantly lower concentration in the\\u000a anoxic zone.

Conny Haraldsson; Stig Westerlund

167

Assimilation of zinc, cadmium, lead, copper, and iron by the spider Dysdera crocata, a predator of woodlice  

SciTech Connect

In this paper, an experiment is described on the assimilation of zinc, cadmium, lead, copper and iron by Dysdera crocata collected from a site in central Bristol. The spiders were fed on woodlice from their own site, and on woodlice from a site contaminated by a smelting works which contained much higher levels of zinc, cadmium and lead than the spiders would have been used to in their normal diet.

Hopkin, S.P.; Martin, M.H.

1985-02-01

168

Cloud model experiments of the effect of iron and copper on tropospheric ozone under marine and continental conditions  

Microsoft Academic Search

Summary We have used a multi-phase cloud photochemistry model to investigate the influence of dissolved iron (Fe) and copper (Cu) on the in-cloud production and loss of ozone and ozone-related species. Comparison of the results of our simulations with and without Fe and Cu reactions for three different photochemical scenarios (marine, averaged continental and polluted continental) indicate that Fe and

J. Matthijsen; P. J. H. Builtjes; D. L. Sedlak

1995-01-01

169

Solidphase extraction of copper, iron and zinc ions on Bacillus thuringiensis israelensis loaded on Dowex optipore V-493  

Microsoft Academic Search

Bacillus thuringiensis israelensis loaded on Dowex optipore V-493 as new adsorbent for the separation–preconcentration of heavy metal ions has been proposed. The analytical conditions for the quantitative recoveries of copper(II), iron(III) and zinc(II) including pH, amounts of adsorbent, sample volume, etc. were investigated. The influences of alkaline and earth alkaline ions were also reported. The recovery values for the analytes

Mustafa Tuzen; Esra Melek; Mustafa Soylak

2008-01-01

170

Specific Inhibition of NEIL-initiated Repair of Oxidized Base Damage in Human Genome by Copper and Iron  

PubMed Central

Dyshomeostasis of transition metals iron and copper as well as accumulation of oxidative DNA damage have been implicated in multitude of human neurodegenerative diseases, including Alzheimer disease and Parkinson disease. These metals oxidize DNA bases by generating reactive oxygen species. Most oxidized bases in mammalian genomes are repaired via the base excision repair pathway, initiated with one of four major DNA glycosylases: NTH1 or OGG1 (of the Nth family) or NEIL1 or NEIL2 (of the Nei family). Here we show that Fe(II/III) and Cu(II) at physiological levels bind to NEIL1 and NEIL2 to alter their secondary structure and strongly inhibit repair of mutagenic 5-hydroxyuracil, a common cytosine oxidation product, both in vitro and in neuroblastoma (SH-SY5Y) cell extract by affecting the base excision and AP lyase activities of NEILs. The specificity of iron/copper inhibition of NEILs is indicated by a lack of similar inhibition of OGG1, which also indicated that the inhibition is due to metal binding to the enzymes and not DNA. Fluorescence and surface plasmon resonance studies show submicromolar binding of copper/iron to NEILs but not OGG1. Furthermore, Fe(II) inhibits the interaction of NEIL1 with downstream base excision repair proteins DNA polymerase ? and flap endonuclease-1 by 4–6-fold. These results indicate that iron/copper overload in the neurodegenerative diseases could act as a double-edged sword by both increasing oxidative genome damage and preventing their repair. Interestingly, specific chelators, including the natural chemopreventive compound curcumin, reverse the inhibition of NEILs both in vitro and in cells, suggesting their therapeutic potential.

Hegde, Muralidhar L.; Hegde, Pavana M.; Holthauzen, Luis M. F.; Hazra, Tapas K.; Rao, K. S. Jagannatha; Mitra, Sankar

2010-01-01

171

Regional distributions of manganese, iron, copper, and zinc in the brains of 6-hydroxydopamine-induced parkinsonian rats  

Microsoft Academic Search

Time courses of changes in manganese, iron, copper, and zinc concentrations were examined in regions of the brain of a 6-hydroxydopamine\\u000a (6-OHDA)-induced rat model of Parkinson’s disease using inductively coupled plasma mass spectrometry (ICP-MS). The concentrations\\u000a were simultaneously determined in brain section at the level of the substantia nigra 1, 3, 7, 10, 14, and 21 days after the\\u000a 6-OHDA treatment

Tohru Tarohda; Yasushi Ishida; Keiichi Kawai; Masayoshi Yamamoto; Ryohei Amano

2005-01-01

172

The effect of occupational lead exposure on blood levels of zinc, iron, copper, selenium and related proteins.  

PubMed

The study objective was to evaluate the effect of occupational lead exposure on blood concentrations of zinc, iron, copper, selenium and proteins related to them, such as transferrin, caeruloplasmin and haptoglobin. The examined group consisted of 192 healthy male employees of zinc-lead works. By the degree of lead exposure, the exposed group was subdivided into three subgroups. The control group was composed of 73 healthy male administrative workers. The markers of lead exposure (blood levels of lead and zinc protoporphyrin) were significantly elevated in the exposed group compared with the control group. Additionally, concentrations of copper and caeruloplasmin were raised. The significant increase in haptoglobin level was observed only in the low exposure group. Selenium levels were significantly decreased, whereas iron, zinc and transferrin levels were unchanged in the exposed group compared with the control group. There were positive correlations between the lead toxicity parameters and the copper and caeruloplasmin levels. In conclusion, the effect of occupational exposure to lead on the metabolism of trace metals appears to be limited. However, significant associations between lead exposure and levels of copper and selenium were shown. Changed levels of positive acute-phase proteins, such as caeruloplasmin and haptoglobin, were also observed. PMID:22923205

Kasperczyk, Aleksandra; Prokopowicz, Adam; Dobrakowski, Micha?; Pawlas, Natalia; Kasperczyk, S?awomir

2012-12-01

173

Steady-State rates of dissolution of stationary iron, cobalt, and nickel cylinders in liquid copper  

NASA Astrophysics Data System (ADS)

The steady-state rate of dissolution of each metal, ?, is determined as a function of its initial concentration in the melt at temperatures in the range 1468 to 1653 K. In the dissolution of an iron or a cobalt cylinder in pure liquid copper, ? increases with increasing temperature and log v varies linearly with 1/T. In every system investigated, ? deviates negatively from the dissolution rate, ?1, expressed by an equation in which it is proportional to the difference between the saturation concentration, X{i/s} (molar fraction), and the bulk concentration, X{i/b}, of a dissolving substance, ?, and follows another equation in which the dissolution rate is proportional to the difference between the activities of ? at X{i/s} and X{i/b} The dissolution rates of iron and cobalt are considered to be controlled by diffusion in the melt. The latter equation is derived from the assumption that the rate of diffusion is proportional to the activity gradient of ?. According to this equation, the deviation of ? from ?, is explained in terms of the ratio of the activity coefficient of ? at X{i/b}, ?i, to that at X{i/s}, ?{i/s}, and the ratio of (??/? X {i/b}) T,X {i/b}=0 to ??1/?X{b/i})T equals that of ?i, at infinite dilution to ?{i/s}. When the standard state of the activity is chosen so that it approaches Xi as Xi approaches zero, the logarithm of the rate constant defined by the latter equation is represented by a straight line as a function of 1/T for all the systems investigated.

Ohno, Reiichi

1982-06-01

174

A 6.2–7.5 GHz tunable bandpass filter with integrated Barium Strontium Titanate (BST) interdigitated varactors utilizing silver\\/copper metallization  

Microsoft Academic Search

A 3rd-order combline tunable filter is implemented utilizing ferroelectric barium strontium titanate (BST) interdigitated varactors. The filter and its varactors are integrated on a ceramic substrate using a simple resistive biasing circuit. Upon the application of a bias voltage ranging from 0 to 40 V the passband of the filter tuned from 6.2 to 7.5 GHz while maintaining a fractional

Zhiping Feng; Wael M. Fathelbab; Peter G. Lam; Vrinda Haridasan; J.-P. Maria; Angus I. Kingon; Michael B. Steer

2009-01-01

175

Mixed messages in iron oxide–copper–gold systems of the Cloncurry district, Australia: insights from PIXE analysis of halogens and copper in fluid inclusions  

Microsoft Academic Search

Proterozoic rocks of the Cloncurry district in NW Queensland, Australia, are host to giant (tens to hundreds of square kilometers)\\u000a hydrothermal systems that include (1) barren regional sodic–calcic alteration, (2) granite-hosted hydrothermal complexes with\\u000a magmatic–hydrothermal transition features, and (3) iron oxide–copper–gold (IOCG) deposits. Fluid inclusion microthermometry\\u000a and proton-induced X-ray emission (PIXE) show that IOCG deposits and the granite-hosted hydrothermal complexes

Timothy Baker; Roger Mustard; Bin Fu; Patrick J. Williams; Guoyi Dong; Louise Fisher; Geordie Mark; Chris G. Ryan

2008-01-01

176

Spectrophotometric study of etodolac complexes with copper (II) and iron (III).  

PubMed

A rapid, simple, and selective method was developed for the determination of etodolac. The method depends on complexation of etodolac with copper (II) acetate and iron (III) chloride followed by extraction of complexes with dichloromethane and then measuring the extracted complexes spectrophotometrically at 684 and 385 nm in case of Cu (II) or Fe (III), respectively. Different factors affecting the reaction, such as pH, reagent concentration, and time, were studied. By use of Job's method of continuous variation, the molar ratio method, and elemental analysis, the stoichiometry of the reaction was found to be in the ratio of 1:2 and 1:3, metal:drug in the case of Cu (II) and Fe (III), respectively. The method obeys Beer's law in a concentration range of 2.00-9.00 and 0.50-2.00 mg/mL in case of Cu (II) and Fe (III), respectively. The stability of the complexes formed was also studied, and the reaction products were isolated for further investigation. The complexes have apparent molar absorptivities of about 32.14 +/- 0.97 and 168.32 +/- 1.12 for Cu (II) and Fe (III), respectively. The suggested procedures were successfully applied to the analysis of pure etodolac and its pharmaceutical formulations. The validity of the procedures was further ascertained by the method of standard additions, and the results were compared with other reported spectrophotometric methods and showed no significant difference in accuracy and precision. PMID:16526444

Amer, Sawsan M; El-Saharty, Yasser S; Metwally, Fadia H; Younes, Kareem M

2005-01-01

177

Microstructure and Mechanical Properties of As-Cast Ductile Irons Alloyed with Manganese and Copper  

NASA Astrophysics Data System (ADS)

The present investigation was carried out to study the effect of manganese and copper addition, singly as well as in combination, on the microstructure, micro-segregation, and mechanical properties of ductile irons. Alloy A (3.18C, 2.64Si, 0.45Mn), alloy B (3.35C, 2.51Si, 0.82Mn), alloy C (3.16C, 2.80Si, 1.08Mn, 0.56Cu), and alloy D (3.18C, 3.00Si, 1.04Mn, 1.13Cu) were melted and cast in the form of Y-block test pieces. The cast microstructures varied from ferrito-pearlitic in alloys A, B, and C to pearlitic in alloy D. However, on XRD analysis and SEM examination, the presence of martensite patches was also detected. There was a marginal decrease in nodule count in alloy B. In alloys C and D, nodule counts were higher, but the proportion of ferrite decreased drastically. Alloy D was found to be the strongest (UTS ? 800 MPa, El = 5%) with alloys A and C coming next in strength; while alloy B was weakest of the four. The presence of martensite patches in association with pearlite appears to be responsible for low toughness of these alloys. Microprobe analysis shows some silicon segregation near the graphite nodules and practically little segregation of manganese. Elemental mapping by FE-SEM does not indicate any manganese segregation.

Dasgupta, Ranjan Kumar; Mondal, Dipak Kumar; Chakrabarti, Ajit Kumar; Ganguli, Ashis Chandra

2012-08-01

178

Reactivity of food phenols with iron and copper ions: binding, dioxygen activation and oxidation mechanisms.  

PubMed

In this work, the affinity of common dietary phenols (gallic acid, caffeic acid, catechin, and rutin) for iron and copper ions was quantitatively investigated in neutral phosphate buffer as well as the reactivity of the complexes toward dioxygen. Contrasting behaviors were observed: because of the competing phosphate ions, Fe(III) binding is much slower than Fe(II) binding, which is rapidly followed by autoxidation of Fe(II) into Fe(III). With both ions, O2 consumption and H2O2 production are modest and the phenolic ligands are only slowly oxidized. By contrast, metal-phenol binding is fast with both Cu(I) and Cu(II). With Cu(I), O2 consumption and H2O2 production are very significant and the phenolic ligands are rapidly oxidized into a complex mixture of oligomers. The corresponding mechanism with Cu(II) is hampered by the preliminary rate-determining step of Cu(II) reduction by the phenols. The consequences of these findings for the stability and antioxidant activity of plant phenols are discussed. PMID:24700074

Nkhili, Ezzohra; Loonis, Michèle; Mihai, Simona; El Hajji, Hakima; Dangles, Olivier

2014-06-28

179

On-line copper and iron removal and selenium(VI) pre-reduction for the determination of total selenium by flow-injection hydride generation-inductively coupled plasma optical emission spectrometry  

Microsoft Academic Search

Selenium was determined in samples with high copper and iron contents by hydride generation-inductively coupled plasma optical emission spectrometry (HG-ICP-OES) after flow-injection (FI) on-line copper and iron removal and selenium(VI) reduction. A Dowex 1X-8 anion-exchange microcolumn was used for the separation of selenium from copper and iron as their chloro-complexes. Se(VI) was then reduced on-line by heating a PTFE coiled

Jorge Stripeikis; Mabel Tudino; Osvaldo Troccoli; Rodolfo Wuilloud; Roberto Olsina; Luis Martinez

2001-01-01

180

Seasonal and locational effects on serum, milk, liver and kidney chromium, manganese, copper, zinc, and iron concentrations of dairy cows.  

PubMed

Chromium (Cr), manganese (Mn), copper (Cu), zinc (Zn), and iron (Fe) concentrations were quantified in serum (n = 112), milk (n = 112), liver (n = 70), and kidney samples (n = 67) of dairy cows from an iron-steel processing region (Payas-Iskenderun) and from an area free of industrial pollution (Antakya) in Hatay, located in Southern Turkey. Samples were collected in the summer and winter and element determinations were carried out by inductively coupled plasma-atomic emission spectrometry. The mean concentrations of selected elements in serum were found to be similar in both regions. Milk samples collected from the nonindustrial region in the summer had higher Cr, Mn, and Zn concentrations than the polluted region. The liver Cu and kidney Mn levels of samples taken from the industrial region in winter were higher than samples of the unpolluted region. Copper and Fe concentrations in milk, Cr, Mn, Zn, and Fe levels in the liver, and Cr, Cu, Zn, and Fe levels in kidney samples were not found to be different among the regions in both seasons. Copper concentrations were below the critical level in the 25% of serum and 32% of liver samples analyzed in this study. Fifteen percent of serum samples and most of the liver samples had lower amounts of Zn than other reported studies. Although slight differences were observed between the industrial and nonindustrial regions, industrial activities and seasonal changes had no significant effect on selected element concentrations on cows and their milk. PMID:15051900

Erdogan, Suat; Celik, Sefa; Erdogan, Zeynep

2004-04-01

181

Factors influencing the DNA nuclease activity of iron, cobalt, nickel, and copper chelates.  

PubMed

A library of complexes that included iron, cobalt, nickel, and copper chelates of cyclam, cyclen, DOTA, DTPA, EDTA, tripeptide GGH, tetrapeptide KGHK, NTA, and TACN was evaluated for DNA nuclease activity, ascorbate consumption, superoxide and hydroxyl radical generation, and reduction potential under physiologically relevant conditions. Plasmid DNA cleavage rates demonstrated by combinations of each complex and biological co-reactants were quantified by gel electrophoresis, yielding second-order rate constants for DNA(supercoiled) to DNA(nicked) conversion up to 2.5 × 10(6) M(-1) min(-1), and for DNA(nicked) to DNA(linear) up to 7 × 10(5) M(-1) min(-1). Relative rates of radical generation and characterization of radical species were determined by reaction with the fluorescent radical probes TEMPO-9-AC and rhodamine B. Ascorbate turnover rate constants ranging from 3 × 10(-4) to 0.13 min(-1) were determined, although many complexes demonstrated no measurable activity. Inhibition and Freifelder-Trumbo analysis of DNA cleavage supported concerted cleavage of dsDNA by a metal-associated reactive oxygen species (ROS) in the case of Cu(2+)(aq), Cu-KGHK, Co-KGHK, and Cu-NTA and stepwise cleavage for Fe(2+)(aq), Cu-cyclam, Cu-cyclen, Co-cyclen, Cu-EDTA, Ni-EDTA, Co-EDTA, Cu-GGH, and Co-NTA. Reduction potentials varied over the range from -362 to +1111 mV versus NHE, and complexes demonstrated optimal catalytic activity in the range of the physiological redox co-reactants ascorbate and peroxide (-66 to +380 mV). PMID:21815680

Joyner, Jeff C; Reichfield, Jared; Cowan, J A

2011-10-01

182

Influence of iron and copper oxides on polychlorinated diphenyl ether formation in heterogeneous reactions.  

PubMed

Polychlorinated diphenyl ether (PCDE) has attracted great attention recently as an important type of environmental pollutant. The influence of iron and copper oxides on formation of PCDEs was investigated using laboratory-scale flow reactors under air and under nitrogen at 350 °C, a temperature corresponding to the post-combustion zone of a municipal solid waste incinerator. The results show that the 2,2',3,4,4',5,5',6-otachlorodiphenyl ether (OCDE) formed from the condensation of pentachlorophenol (PCP) and 1,2,4,5-tetrachlorobenzene (Cl4Bz) is the predominant congener formed on the SiO2/Fe2O3 surface with and without oxygen. This indicated that HCl elimination between PCP and 1,2,4,5-Cl4Bz molecules formed 2,2',3,4,4',5,5',6-OCDE in the presence of Fe2O3. On the other hand, decachlorodiphenyl ether, nonachlorodiphenyl ether, and OCDE were the dominant products on the SiO2/CuO surface without oxygen, although the 2,2',3,4,4',5,5',6-OCDE was the dominant product on the SiO2/CuO surface with oxygen. Therefore, the presence of Fe2O3 and CuO influences the formation and homologue distribution of PCDEs, which shifted towards the lower chlorinated species. Fe2O3 can promote both the condensation and dechlorination reaction without oxygen. On the contrary, with oxygen, Fe2O3 suppresses the condensation of chlorobenzene and chlorophenol to form PCDEs and polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). CuO can increase the formation of lower chlorinated PCDEs and PCDDs without oxygen. In conclusion, the different fly ash components have a major influence on PCDE emissions. PMID:23440438

Liu, Wenxia; Shen, Lianfeng; Zhang, Fawen; Liu, Wenbin; Zheng, Minghui; Yang, Xitian

2013-08-01

183

Barium enema (image)  

MedlinePLUS

A barium enema is performed to examine the walls of the colon. During the procedure, a well lubricated enema tube is inserted gently into the rectum. The barium, a radiopaque (shows up on X-ray) contrast ...

184

Iron, zinc, copper and selenium status of breast-fed infants and infants fed trace element fortified milk-based infant formula.  

PubMed

Infants were fed cow's milk-based formulas containing 4 mg of iron/l from 1.5 to 6 months of age and their hematological status was compared to infants receiving the same formula but with 7 mg of iron/l and with breast-fed infants. One formula with 4 mg of iron/l contained iron as ferrous sulfate, in another, part of the iron was provided as bovine lactoferrin. We also studied the effect of selenium (10 micrograms/l) and copper (0.4 mg/l) supplementation on selenium and copper status. There were no significant differences in hematological indices among the groups at 6 months of age; all infants had satisfactory iron status. Serum transferrin receptor levels, a potential novel indicator of iron status, were highest in breast-fed infants, suggesting a cellular need for iron, and lowest in infants receiving formula with 7 mg of iron/l. Selenium status, as assessed by serum glutathione peroxidase activity, was similar at 6 months of age in breast-fed infants and infants fed formula fortified with selenium but lower in infants fed unfortified formula. The lowest levels of glutathione peroxidase activity were found in infants fed the highest concentration of iron (7 mg/l). Serum copper concentrations were similar in all groups, but the lowest levels were found in infants fed the highest concentration of iron. These results suggest that 4 mg of iron/l is adequate for infants up to 6 months of age and that higher levels may have some negative effects. PMID:8025391

Lönnerdal, B; Hernell, O

1994-04-01

185

Zinc, iron, manganese, and magnesium accumulation in crayfish populations near copper-nickel smelters at Sudbury, Ontario, Canada  

SciTech Connect

The Sudbury basin has been subjected to extreme ecological disturbances from logging, mining and smelting activities. Elevated concentrations of copper, cadmium, and nickel have been reported in crayfish populations close to the Sudbury smelting works. The present study compares concentrations of zinc (Zn), iron (Fe), manganese (Mn) and magnesium (Mg) in freshwater crayfish at selected distances of the habitat from the emission source. These metals were selected since they are known to be emitted in moderately high quantities into the Sudbury environment as byproduct of the smelting process. Various tissue concentrations in crayfish were also examined to determined specific tissue sites for these accumulations.

Bagatto, G.; Alikhan, M.A.

1987-06-01

186

Structural state of surface layers of aluminum after laser alloying using a mixture of copper and iron powders  

NASA Astrophysics Data System (ADS)

X-ray diffraction, metallographic, and electron-microscopic methods were used to study the regularities of the structure formation in the surface layers of aluminum upon pulse laser alloying using copper and iron powders taken in an atomic ratio of two to one. It is shown that, in the zone of laser alloying, a quasicrystalline phase can form, which leads to a considerable increase in microhardness. The effect of the thickness of the alloying layer on the structural and phase state of the laser-affected zone is analyzed.

Girzhon, V. V.; Smolyakov, A. V.; Tantsyura, I. V.

2008-10-01

187

Attenuation in iron of neutrons produced by 120 GeV/c positive hadrons on a thick copper target  

NASA Astrophysics Data System (ADS)

A deep penetration experiment in a thick iron shield was carried out at CERN, at the CERN-EU high-energy Field (CERF) facility. A 120 GeV/c positive hadron beam impinged on a 50 cm thick copper target located inside an irradiation cave covered by an iron shield, the thickness of which could be varied from 40 to 240 cm. Measurements of neutron fluence and ambient dose equivalent were performed with a Bonner Sphere Spectrometer and an extended-range rem counter and the results compared with Monte Carlo simulations carried out with the FLUKA code. A comparison with literature data shows an acceptable agreement. A discussion is also given on the contribution of the neutron background and of its influence on a deep penetration experiment.

Agosteo, Stefano; Pozzi, Fabio; Silari, Marco; Ulrici, Luisa

2013-10-01

188

Influence of iron and copper consumption on weight gain and oxidative stress in adipose tissue of Wistar rats  

PubMed Central

The aim of the present study was to assess the effect of iron and copper consumption on weight gain and development of oxidative stress in adipose tissue of rats. Control rats obtained pure drinking water. Iron-treated groups of animals obtained FeSO4•12H2O with drinking water in concentrations of 3 and 6 mg/l, while copper-treated rats obtained CuSO4 in concentrations of 4.88 and 9.76 mg/l. The animals of the 6th group received a mixture of FeSO4•12H2O and CuSO4 in the respective concentrations of 3 and 4.88 mg/l in drinking water. All animals received a standard chow. The final weight of rats from all the experimental groups, especially in those obtaining the combination of iron and cooper, exceeded the control values. Maximal weight of fat pads was observed in animals receiving drinking water with 3 mg/l FeSO4•12H2O, 4.88 and 9.76 mg/l CuSO4, and the mixture of FeSO4•12H2O and CuSO4. The maximal intensity of free radical processes, as estimated by the concentration of fluorescent modified amino acids and the intensity of chemiluminescence in adipose tissue homogenates, was observed in rats obtaining iron in the concentration of 3 mg/l in the drinking water.

Ajsuvakova, Olga P.; Shehtman, Alexandr M.; Boev, Viktor M.; Nikonorov, Alexandr A.

2012-01-01

189

Identification of genes involved in the toxic response of Saccharomyces cerevisiae against iron and copper overload by parallel analysis of deletion mutants.  

PubMed

Iron and copper are essential nutrients for life as they are required for the function of many proteins but can be toxic if present in excess. Accumulation of these metals in the human body as a consequence of overload disorders and/or high environmental exposures has detrimental effects on health. The budding yeast Saccharomyces cerevisiae is an accepted cellular model for iron and copper metabolism in humans primarily because of the high degree of conservation between pathways and proteins involved. Here we report a systematic screen using yeast deletion mutants to identify genes involved in the toxic response to growth-inhibitory concentrations of iron and copper sulfate. We aimed to understand the cellular responses to toxic concentrations of these two metals by analyzing the different subnetworks and biological processes significantly enriched with these genes. Our results indicate the presence of two different detoxification pathways for iron and copper that converge toward the vacuole. The product of several of the identified genes in these pathways form molecular complexes that are conserved in mammals and include the retromer, endosomal sorting complex required for transport (ESCRT) and AP-3 complexes, suggesting that the mechanisms involved can be extrapolated to humans. Our data also suggest a disruption in ion homeostasis and, in particular, of iron after copper exposure. Moreover, the identification of treatment-specific genes associated with biological processes such as DNA double-strand break repair for iron and tryptophan biosynthesis for copper suggests differences in the mechanisms by which these two metals are toxic at high concentrations. PMID:17785683

Jo, William J; Loguinov, Alex; Chang, Michelle; Wintz, Henri; Nislow, Corey; Arkin, Adam P; Giaever, Guri; Vulpe, Chris D

2008-01-01

190

Bacterial Reduction of Copper-Contaminated Ferric Oxide: Copper Toxicity and the Interaction Between Fermentative and Iron-Reducing Bacteria  

Microsoft Academic Search

.   Fe(III) oxide is an important heavy-metal sink, and bacteria are responsible for much of the Fe(III) reduced in nonsulfidogenic\\u000a aquatic environments, yet factors governing the bacterial reduction of heavy metal–contaminated iron oxide are largely unknown.\\u000a In this study with a stabilized bacterial consortium enriched from metal-contaminated sediments, we demonstrate that Cu toxicity\\u000a impedes anaerobic carbon oxidation and bacterial reduction

J. T. Markwiese; P. J. S. Colberg

2000-01-01

191

Bosonics in the copper and iron based high transition temperature superconductors  

NASA Astrophysics Data System (ADS)

It has been long established that the phenomenon of superconductivity is administered by lattice deformations (phonons) which act to pair electrons into spinless bosons free to condense into a coherent ground state. This superconducting phase is protected up to a critical temperature above which thermal fluctuations are potent enough to destroy the resistance free phase. The strength of this phonon mediation has been calculated by strong coupling theory and found to be capable of accommodating pairing up to near 40 K. So with the advent of copper-oxide (cuprate) superconductors boasting transitions temperatures exceeding 90 K it was clear that these material represented a new breed of superconducting physics. More than twenty years after the initial discovery of these high-transition temperatures the most basic questions are yet to be answered, the most fundamental of which is by what mechanism does pairing occur? The field splits between those who feel that a boson mediator is still necessary to act as the virtual glue which binds electrons into cooper pairs while others insist that really the Coulomb force alone is enough to induce pairing physics. Even within the boson-seeker community there is no consensus on what particular type of boson is contained in this system whether it be a lattice excitation or spin excitation. This answer has been clouded by previous experimental results on the hole-doped cuprates which have made strong cases for every scenario rendering them largely inconclusive. For this answer though it is possible to explore materials that have not yet been clouded by conflicting results by performing the first high resolution ultra-high-vacuum low-temperature scanning tunneling microscopy (STM) study of an electron-doped cuprate. A distinct and unambiguous bosonic mode is found at energy near 10.5 meV. Through comparison with other experimental data it is found that this mode does not fit the characteristics of a phonon. It is found, through comparison with neutron scattering experiments on the same sample, that this mode is consistent with a spin collective mode. Further more it is found that this mode is linked with the strength of superconductivity nominating it as the possible electron pairing mechanism. Doping and temperature dependence studies are performed to investigate this possibility. Finally the same procedures developed can be applied to the newly discovered iron based superconductors which may represent yet another type of new superconductor physics. Initial results on the first bosonic mode STM study of SrFe 2-xCoxAs 2 and BaFe2-xCo xAs2 are presented.

Niestemski, Francis Charles

192

Coprecipitation with yttrium phosphate as a separation technique for iron(III), lead, and bismuth from cobalt, nickel, and copper matrices.  

PubMed

The coprecipitation behavior of 44 elements (47 ions because of chromium(III,VI), arsenic(III,V), and antimony(III,V)) with yttrium phosphate was investigated at various pHs. Yttrium phosphate could quantitatively coprecipitate iron(III), lead, bismuth, and indium over a wide pH range; however, 18 ions, including alkali metals and oxo anions, such as vanadium(V), chromium(VI), molybdenum(VI), tungsten(VI), germanium(IV), arsenic(III,V), selenium(IV), and tellurium(VI), were scarcely collected. In addition, 19 ions, including cobalt, nickel, and copper(II), were hardly coprecipitated at pHs below about 3. Based on these results, the separation of iron(III), lead, and bismuth from cobalt, nickel, and copper(II) matrices was investigated. Iron(III), lead, and bismuth ranging from 0.5 to 25mug could be separated effectively from a solution containing 0.5g of cobalt, nickel, or copper at pH 3.0. The separated iron(III), lead, and bismuth could be determined by inductively coupled plasma atomic emission spectrometry using internal standardization. The detection limits (3sigma, n=7) of iron(III), lead, and bismuth were 0.008, 0.137, and 0.073mug, respectively. The proposed method was applied to the analyses of metals and chlorides of cobalt, nickel, and copper. PMID:18970141

Kagaya, Shigehiro; Araki, Yasuko; Hirai, Noriyasu; Hasegawa, Kiyoshi

2005-07-15

193

Determination of iron and copper in seawater at pH 1.7 with a new commercially available chelating resin, NTA Superflow  

Microsoft Academic Search

The use of a commercially available chelating resin with NTA-type functional groups for concentration of trace metals from seawater is described. Trace metal recoveries from this NTA Superflow chelating resin are pH dependent. At a pH of ?2 only iron(III) and copper are quantitatively recovered from the resin. Iron(II) cannot be quantitatively recovered from this resin below a pH of

Maeve C. Lohan; Ana M. Aguilar-Islas; Robert P. Franks; Kenneth W. Bruland

2005-01-01

194

Synthesis of a chitosan derivative recognizing planar metal ion and its selective adsorption equilibria of copper(II) over iron(III) 1  

Microsoft Academic Search

In order to improve the selectivity of copper(II)\\/iron(III), crosslinked N-(2-pyridyhnethyl)chitosan (PMC) with lower affinity for iron(III) was synthesized by crosslinking the Schiff's base formed in order to prevent amino groups to be metal adsorption sites from a attack of (chloromethyl)oxirane. The final chitosan derivative, PMC, was obtained by reducing the imine moiety of the Schiff's base with sodium borohydride. By

Yoshinari Baba; Koichi Masaaki; Yoshinobu Kawano

1998-01-01

195

Effect of excess dietary iron as ferrous sulfate and excess dietary ascorbic acid on liver zinc, copper and sulfhydryl groups and the ovary  

SciTech Connect

Female guinea pigs of the NIH 13/N strain, weighing between 475 and 512 g, were fed diets supplemented with 50 to 2500 mg of iron per kg of diet as ferrous sulfate and 0.2 to 8.0 g of ascorbic acid per kg of diet. A significant effect was observed on tissue copper and zinc, ovary weight and liver protein sulfhydryl groups. The mean ovary weight for guinea pigs fed 2500 mg of iron was significantly less than that of animals fed 50 mg of iron, 0.045 +/- 0.012 g and 0.061 +/- 0.009 g, respectively. Liver zinc content of animals fed 2500 mg of iron and 200 mg of ascorbic acid per kg of diet was significantly less than that of animals fed 50 mg of iron and 200 mg of ascorbic acid, 16.3 +/- 3.3 ..mu..g and 19.6 +/- 1.6 ..mu..g, respectively. There was no difference in liver copper due to dietary iron, but when dietary ascorbic acid was increased to 8 g per kg of diet, there was a significant decrease (from 22.8 +/- 8.1 ..mu..g to 10.5 +/- 4.8 ..mu..g) in liver copper. Excess dietary ascorbic acid decreased ovarian zinc significantly when increased to 8 g per kg of diet, 2929 +/- 919 ..mu..g vs 1661 +/- 471 ..mu..g, respectively, when compared to the control group.

Edwards, C.H.; Adkins, J.S.; Harrison, B.

1986-03-05

196

Barium titanium glycolate: A new barium titanate powder precursor  

SciTech Connect

This paper describes the synthesis and structure of a barium titanium glycolate complex and the calcination into barium titanate preceramic powders that sinter into polycrystalline, tetragonal barium titanate having good dielectric properties.

Day, V.W.; Klemperer, W.G.; Payne, D.A. [Univ. of Nebraska, Lincoln, NE (United States)] [and others] [Univ. of Nebraska, Lincoln, NE (United States); and others

1996-02-01

197

Barium titanium glycolate: A new barium titanate powder precursor  

Microsoft Academic Search

This paper describes the synthesis and structure of a barium titanium glycolate complex and the calcination into barium titanate preceramic powders that sinter into polycrystalline, tetragonal barium titanate having good dielectric properties.

Victor W. Day; W. G. Klemperer; D. A. Payne; Shurong Liang

1996-01-01

198

Preparing Copper Powder from Cemented Copper.  

National Technical Information Service (NTIS)

Techniques were developed for preparing metallurgical-grade copper powder from industrially produced cement copper. Flotation was used for rejecting discrete gangue particles, acid leaching to remove residual iron and aluminum, hydrogen reduction to elimi...

J. K. Winter L. G. Evans R. D. Groves

1971-01-01

199

[Vitamin and mineral supplements in the diet of military personnel: effect on the balance of iron, copper and manganese, immune reactivity and physical work-capacity].  

PubMed

Conducted with the participation of 50 students of military educational study the effect of various vitamin and mineral complexes for the provision by the body naturally iron, copper and manganese on the immune and physical status. Found that diets enriched BMV was accompanied by a significant delay in the micro-elements, mainly iron, which indicates a deficiency of these bioelements in chickens Santo during the summer. Under the influence of vitamin-mineral complexes significantly increased rates of natural and specific immunity. As the delay increases significantly increased iron medical indicators of immunological reaction efficiency and physical performance. PMID:22686030

Za?tseva, I P; Nosolodin, V V; Za?tsev, O N; Gladkikh, I P; Koznienko, I V; Beliakov, R A; Arshinov, N P

2012-03-01

200

Iron  

Microsoft Academic Search

Iron poisoning causes its metabolic effects in proportion to the concentrations of free iron. Toxicity is therefore related to dose ingested. The amount of iron in different salts varies, and iron concentrations may rise and fall, making plasma concentrations difficult to interpret in acute poisoning. Clinical features include severe gastrointestinal irritation, cardiovascular collapse and direct organ damage to liver and

D. Nicholas Bateman

2007-01-01

201

An association among iron, copper, zinc, and selenium, and antioxidative status in dyslipidemic pediatric patients with glycogen storage disease types IA and III  

Microsoft Academic Search

Dyslipidemia in patients with glycogen storage disease types Ia (GSD Ia) and III (GSD III) does not lead to premature atherosclerosis. The aim of this study was to investigate the association among serum copper (Cu), zinc (Zn), iron (Fe), and selenium (Se) concentrations, and their carrier proteins: ceruloplasmin, albumin, and related antioxidant enzyme activities [superoxide dismutase (SOD), catalase (CAT), glutathione

Sema Kalkan Ucar; Mahmut Coker; Eser Sözmen; Damla Goksen Simsek; Sukran Darcan

2010-01-01

202

Preconcentration and determination of iron and copper in spice samples by cloud point extraction and flow injection flame atomic absorption spectrometry.  

PubMed

A flow injection (FI) cloud point extraction (CPE) method for the determination of iron and copper by flame atomic absorption spectrometer (FAAS) has been improved. The analytes were complexed with 3-amino-7-dimethylamino-2-methylphenazine (Neutral Red, NR) and octylphenoxypolyethoxyethanol (Triton X-114)wasadded as a surfactant. The micellar solutionwasheated above 50 degrees C and loaded through a column packed with cotton for phase separation. Then the surfactant-rich phase was eluted using 0.05 mol L(-1) H2SO4 and the analytes were determined by FAAS. Chemical and flow variables influencing the instrumental and extraction conditions were optimized. Under optimized conditions for 25 mL of preconcentrated solution, the enrichment factors were 98 and 69, the limits of detection (3s) were 0.7 and 0.3 ng mL(-1), the limits of quantification (10s) were 2.2 and 1.0 ng mL(-1) for iron and copper, respectively. The relative standard deviation (RSD) for ten replicate measurements of 10 ng mL(-1) iron and copper were 2.1% and 1.8%, respectively. The proposed method was successfully applied to determination of iron and copper in spice samples. PMID:20627408

Sahin, Ci?dem Arpa; Tokgöz, Ilknur; Bekta?, Sema

2010-09-15

203

Determination of copper, lead and iron in water and food samples after column solid phase extraction using 1-phenylthiosemicarbazide on Dowex Optipore L-493 resin.  

PubMed

A novel solid phase extraction procedure for determination of copper, lead and iron in natural water and food samples has been established in the presented work. 1-Phenylthiosemicarbazide (1-PTSC) as ligand and Dowex Optipore L-493 resin as adsorbent were used in a mini chromatographic column. Various analytical conditions for the quantitative recoveries of analyte ions including pH, amounts of adsorbent, eluent, sample volume, etc. were investigated. The recovery values for analyte ions were higher than 95%. The determination of copper, lead and iron was performed by flame atomic absorption spectrometry. The influences of some alkali, alkali earth and transition metals on the recoveries of analyte ions were investigated. The preconcentration factor was 62.5. The limit of detections of the understudied analytes (k=3, N=21) were 0.64 ?g L(-1) for copper, 0.55 ?g L(-1) for lead and 0.82 ?g L(-1) for iron. The relative standard deviation was found to be lower than 6%. The accuracy of the method was confirmed with certified reference material (GBW 07605 Tea). The method was successively applied for the determination of copper, lead and iron in water and some food samples including cheese, bread, baby food, pekmez, honey, milk and red wine after microwave digestion. PMID:21111769

Yildiz, Ozden; Citak, Demirhan; Tuzen, Mustafa; Soylak, Mustafa

2011-02-01

204

Molecular Structure of Barium Chloride  

NSDL National Science Digital Library

Barium Chloride was the byproduct of the discovery of radium by Madame Curie. When refining radium, the final separation resulted in barium chloride and radium chloride. Electrophoresis of barium chloride produces small-scale amounts of barium atom. This can be used for obtaining barium for commercial uses. Applications of barium chloride include stimulating the heart and other muscles for medicinal purposes, and also for softening water. Other uses of barium chloride include the manufacturing of barium salts, as pesticide, pigments, boiler detergent, in purifying sugar, as mordant in dyeing and printing textiles, and in the manufacture of caustic soda, polymers, and stabilizers.

2002-08-15

205

The levels of cadmium, nickel, manganese lead, zinc, iron, tin, copper and arsenic in the brined canned Jordanian cheese.  

PubMed

The levels of cadmium, nickel, manganese, lead, zinc, iron, tin, copper and arsenic in fresh sheep's milk, white brined cheese preserved in glass jars and in tin containers and their corresponding brines, salt and tin plates were determined by atomic absorption spectrophotometry. The results have been compared with those reported in recent years. Although metal levels were comparable with other investigators' data, our data shows that white brined cheese picked-up metals from tin containers and from the naturally contaminated salt, on the contrary brined cheese in preserved glass jars showed lower levels of metals. We recommend a purified salt for brine preparation and glass jars for white cheese preservation in order to minimize cheese contamination with metals from tin cans and salt. PMID:8212904

Ereifej, K I; Gharaibeh, S H

1993-08-01

206

Calculation of binodals and spinodals in multicomponent alloys by different statistical methods with application to iron-copper-manganese alloys  

SciTech Connect

A generalization of the pair-cluster (PC) approximation in the theory of disordered systems to multicomponent alloys is proposed. It is shown that phase equilibrium boundaries (binodals) calculated in the mean-field (MF) approximation, which is used in standard calculations of phase diagrams by the CALPHAD method, coincide with the results of rigorous calculations for dilute alloys; however, the application of these methods to calculating the boundaries of the stability region with respect to the decomposition of an alloy (spinodals) leads to large errors. At the same time, in the PC approximation, the description of all statistical properties, including binodals and spinodals, turns out to be exact for dilute alloys. The methods developed are illustrated by an example of iron-copper-manganese ternary alloys.

Vaks, V. G., E-mail: vaks@mbslab.kiae.ru; Zhuravlev, I. A.; Khromov, K. Yu. [Russian Research Centre Kurchatov Institute (Russian Federation)

2010-11-15

207

Sputtered (barium(x), strontium(1-x))titanate, BST, thin films on flexible copper foils for use as a non-linear dielectric  

NASA Astrophysics Data System (ADS)

Ferroelectric thin film dielectrics have a non-linear DC bias dependent permittivity and can be used as the dielectric between metal electrodes to make tunable Metal-Insulator-Metal (MIM) capacitors. Varactors can be used to change the resonance frequency of a circuit allowing high speed frequency switching intra- and inter-band. 2-D geometric arrays of circuitry, where resonant frequency is independently controlled by tunable elements in each section of the array, allow electromagnetic radiation to be focused and the wave front spatial trajectory controlled. BST thin films varactors allow large DC fields to be applied with modest voltages providing large tunabilities. If ferroelectric thin film based devices are to complement or supplant semiconductor varactors as tunable elements then devices must be synthesized using a low cost processing techniques. The Film on Foil process methodology for depositing BST thin films on copper foil substrates was used to create BST/Cu specimens. Sputtering conditions were determined via BST deposition on platinized silicon. Sputtered BST thin films were synthesized on Cu foil substrates and densified using high T, controlled pO2 anneals. XRD showed the absence of Cu2O in as-deposited, post crystallization annealed, and post "re-ox" annealed state. Data showed a polycrystalline BST microstructure with a 55--80 nm grain size and no copper oxidation. HRTEM imaging qualitatively showed evidence of an abrupt BST/Cu interface free from oxide formation. Dielectric properties of Cu/BST/Pt MIM devices were measured as a function of DC bias, frequency, and temperature. A permittivity of 725 was observed with tunability >3:1 while zero bias tan delta of 0.02 saturating to tan delta < 0.003 at high DC bias. No significant frequency dispersion was observed over five decades of frequency. Temperature dependent measurements revealed a broad ferroelectric transition with a maximum at -32°C which sustains a large tunability over -150°C to 150°C. Sputtered BST thin films on copper foils show comparable dielectric properties to CVD deposited films on platinized silicon substrates proving sputtered BST/Cu specimens can reproduce excellent properties using a more cost-effective processing approach. A concept for reducing the temperature dependence was explored. Stacks of multiple compositions of BST thin films were considered as an extension of core-shell structures to a thin film format. Temperature profiles of BST/Cu films were modeled and mathematically combined in simulations of multi-composition film stacks. Simulations showed singular composition BST thin films could meet X7R specifications if a film has a 292 K < TC < 330 K. Simulations of series connected film stacks show only modest temperature profile broadening. Parallel connected dual composition film stacks showed a 75°C temperature range with essentially flat capacitance by simulating compositions that create a DeltaTC = 283°C. Maximum permittivity and temperature profile shape independent of film thickness or composition were assumed for simulations. BST/Cu thickness and compositions series were fabricated and dielectric properties characterized. These studies showed films could be grown from 300 nm and approaching 1 mum without changing the dielectric temperature response. In studying BST composition, an increasing TC shift was observed when increasing Ba mole fraction in BST thin films while tunability >3:1 was maintained. These results provide a route for creating temperature stable capacitors using a BST/Cu embodiment. An effort to reduce surface roughness of copper foil substrates adversely impacted BST film integrity by impairing adhesion. XPS analysis of high surface roughness commercially obtained Cu foils revealed a surface treatment of Zn-Cu-O that was not present on smooth Cu, thus an investigation of surface chemistry was conducted. Sessile drop experiments were performed to characterize Cu-BST adhesion and the effects of metallic Zn and ZnO in this system. The study revealed the work of adhesio

Laughlin, Brian James

208

Interactions of free copper (II) ions alone or in complex with iron (III) ions with erythrocytes of marine fish Dicentrarchus labrax.  

PubMed

As a consequence of human activity, various toxicants - especially metal ions - enter aquatic ecosystems and many fish are exposed to considerable levels. As the free ion and in some complexes, there is no doubt that copper promotes damage to cellular molecules and structures through radical formation. Therefore, we have investigated the influence of copper uptake by the red blood of the sea bass (Dicentrarchus labrax), and its oxidative action and effects on cells in the presence of complexed and uncomplexed Fe3+ ions. Erythrocytes were exposed to various concentrations of CuSO4, Fe(NO3)3, and K3Fe(CN)6 for up to 5h, and the effects of copper ions alone and in the combination with iron determined. The results show that inside the cells cupric ion interacts with hemoglobin, causing methemoglobin formation by direct electron transfer from heme Fe2+ to Cu2+. Potassium ferricyanide as a source of complexed iron decreases Met-Hb formation induced by copper ions unlike Fe(NO3)3. We also found that incubation of fish erythrocytes with copper increased hemolysis of cells. But complexed and uncomplexed iron protected the effect of copper. CuSO4 increased the level of lipid peroxidation and a protective effect on complexed iron was observed. Incubation of erythrocytes with copper ions resulted in the loss of a considerable part of thiol content at 10 and 20 microM. This effect was decreased by potassium ferricyanide and Fe(NO3)3 only after 1 and 3h of incubation. The level of nuclear DNA damage assayed by comet assay showed that 20 microM CuSO4 as well as 20 microM Fe(NO3)3 and 10 mM K3Fe(CN)6 induce single- and double-strand breaks. The lower changes were observed after the exposure of cells to K3Fe(CN)6. The data suggest that complexed iron can act protectively against copper ions in contrast to Fe(NO3)3. PMID:19524693

Labieniec, Magdalena; Milowska, Katarzyna; Balcerczyk, Aneta; Rucinska, Agata; Sadowska, Magdalena; Jokiel, Marta; Brichon, Gerard; Gabryelak, Teresa

2009-09-01

209

The determination of aluminum, copper, iron, and lead in glycol formulations by atomic absorption spectroscopy  

NASA Technical Reports Server (NTRS)

Initial screening tests and the results obtained in developing procedures to determine Al, Cu, Fe, and Pb in glycol formulations are described. Atomic absorption completion was selected for Cu, Fe and Pb, and after comparison with emission spectroscopy, was selected for Al also. Before completion, carbon, iron, and lead are extracted with diethyl dithio carbamate (DDC) into methyl isobutyl ketone (MIBK). Aluminum was also extracted into MIBK using 8-hydroxyquinoline as a chelating agent. As little as 0.02 mg/l carbon and 0.06 mg/l lead or iron may be determined in glycol formulations. As little as 0.3 mg/l aluminum may be determined.

1977-01-01

210

Ferric iron uptake genes are differentially expressed in the presence of copper sulfides in Acidithiobacillus ferrooxidans strain LR.  

PubMed

Acidithiobacillus ferrooxidans is one of the most widely used microorganisms in bioleaching operations to recover copper from low-grade copper sulfide ores. This work aimed to investigate the relative expression of genes related to the iron uptake system when A. ferrooxidans LR was maintained in contact with chalcopyrite or bornite as the sole energy source. Real-time quantitative PCR analysis revealed that the presence of bornite had no effect on the expression of seven genes related to the siderophore-mediated Fe(III) uptake system, while in the presence of chalcopyrite the expression of the genes was up-regulated. Bioinformatic analysis of the genomic region where these genes were found revealed the existence of three new putative DNA-binding sequences for the ferric iron uptake transcriptional regulator (Fur). Electrophoretic mobility shift assays demonstrated that a purified A. ferrooxidans His-tagged Fur protein was able to bind in vitro to each of these putative Fur boxes, suggesting that Fur regulated the expression of these genes. The expression of fur and two known Fur-regulated genes, mntH and dsrK, was also investigated in the presence of chalcopyrite. While the expression of fur and mntH was up-regulated, the expression of dsrK was down-regulated. The low amount of ferrous iron in the medium was probably responsible for the up-regulation of fur and the genes related to the siderophore-mediated Fe(III) uptake system when A. ferrooxidans LR was kept in the presence of chalcopyrite. A homology model of the A. ferrooxidans Fur was constructed and revealed that the putative DNA-binding surface presents conserved positively charged residues, supporting a previously suggested mode of interaction with DNA. The up-regulation of fur and the siderophore-mediated Fe(III) uptake genes, and the down-regulation of dsrK suggest that in the presence of chalcopyrite Fur acts as a transcription inducer and repressor. PMID:21132364

Ferraz, Lúcio F C; Verde, Leandro C L; Vicentini, Renato; Felício, Ana P; Ribeiro, Marcelo L; Alexandrino, Fabiana; Novo, Maria T M; Garcia, Oswaldo; Rigden, Daniel J; Ottoboni, Laura M M

2011-03-01

211

Laser-initiated combustion studies of selected aluminum, copper, iron, and nickel alloys  

NASA Technical Reports Server (NTRS)

The results of combustion studies at atmospheric pressure on ten metal alloys are presented. The alloys studied were aluminum alloys 1100, 2219, 6061, and tensile-50; 304, 347 and 21-6-9 stainless steel; inconel 600; beryllium copper and a bronze. It was found that once ignition was achieved all alloys would generally burn to completion. The overall combustion process appears to obey a first order rate process. Preliminary conclusions are presented along with recommendations for future work.

Bransford, J. W.; Clark, A. F.

1981-01-01

212

Recovering iron, manganese, copper, cobalt, and high-purity nickel from sea nodules  

NASA Astrophysics Data System (ADS)

Many studies have investigated methods of recovering valuable metals from sea nodules. Recently, a research group in Japan developed a smelting and chlorine process after investigating a variety of existing processes and comparing their respective efficiencies with the same nodules. The best results were obtained by combining pyrometallurgical and hydrometallurgical treatments, which enabled the efficient recovery of manganese, nickel, copper, and cobalt. High-purity nickel can be also produced through further solvent extraction.

Kohga, Tetsuyoshi; Imamura, Masaki; Takahashi, Junichi; Tanaka, Nobuhiro; Nishizawa, Tokuo

1995-12-01

213

Composition and Atomic Structure of Two Ordering Binary-Alloy Surfaces: COPPER(3)GOLD(110) and IRON(TIN)(100)  

NASA Astrophysics Data System (ADS)

The composition and atomic structure of the top two layers of the Cu_3Au(110) surface were studied as a function of temperature to understand segregation in a model ordered alloy. A combination of Auger electron spectroscopy, low-energy electron diffraction, low-energy ion scattering, and molecular statics calculations with many-body potentials, revealed behavior that was different from the previously-investigated Cu_3Au(100) surface. The pattern of planes consisting of equal parts copper and gold, alternating with planes of pure copper, was found to be disrupted at the (110) surface. The bulk was terminated at a Cu-Au layer, which had a slight depletion of gold (45%) at room temperature. The second layer, nominally a pure copper plane, contained a substantial amount of gold (25%). The top two surface layers each reached 35% gold below the bulk ordering temperature of 390 ^circC. The differences between the (110) and the (100) surfaces were ascribed to differences in the "effective" coordination number of first-layer atoms. When annealed below 150^circC, the (110) surface was found to be reconstructed, with every other copper (001) row removed from the surface. The newly -exposed second-layer lattice sites were found to be occupied preferentially by gold. Surface-stress-tensor arguments are used to describe the origin of this reconstruction. Iron crystals doped with tin are known to exhibit segregation of more than one monolayer of tin to the (100) surface. This unusually large coverage raises the question of whether the multilayer enrichment is due to equilibrium segregation or to some kind of metastable precipitation phenomenon. In the latter case, the presence of the equilibrium bulk second phase, FeSn, would be expected to cause a reduction in the surrounding tin coverage. This issue was addressed by the use of chemical-vapor deposition to seed the surface of a tin-doped crystal with FeSn. It was found that the presence of this second phase did not alter the equilibrium surface coverage, which returned quickly to its previous level by surface diffusion from the FeSn crystallites.

Wallace, William Edward, III

214

Wear mechanism of copper alloy wire sliding against iron-base strip under electric current  

Microsoft Academic Search

In electric railways, the wear rate of trolley wire decides the life of the wire. In order to search for methods of decreasing the wear rate. laboratory wear test was carried out with three types of wire materials sliding against an iron-base sintered alloy strip under electric current flow condition. The test results indicate that the wear rate of wire

Hiroki Nagasawa; Koji Kato

1998-01-01

215

First-principles pseudopotential study of structures of iron on copper ( 001) surface  

Microsoft Academic Search

An ab initio pseudopotential density functional study of iron on Cu(001) surfaces is presented. No surface relaxation is found on clean Cu(001) surface, while small first layer expansions are found for both the monolayer and double layer Fe coverage. The total energies of various surfaces are calculated and compared. It is concluded that a proposed bilayer growth mode is not

X. W. Wang

1995-01-01

216

Structure and properties of clusters of self-interstitial atoms in fcc copper and bcc iron  

Microsoft Academic Search

Static and molecular dynamics simulations have been used with different types of interatomic potentials to investigate the structure, properties and stability of self-interstitial atom (SIA) clusters produced during irradiation. In f-iron (Fe), faulted clusters of dumbbells are unstable for all the potentials. The most stable SIA clusters are sets of parallel crowdions. Large clusters of this type form perfect dislocation

Yu. N. Osetsky; A. Serra; B. N. Singh; S. I. Golubov

2000-01-01

217

Structure and properties of clusters of self-interstitial atoms in fcc copper and bcc iron  

Microsoft Academic Search

Static and molecular dynamics simulations have been used with different types of interatomic potentials to investigate the structure, properties and stability of self-interstitial atom (SIA) clusters produced during irradiation. In ?-iron (Fe), faulted clusters of <110> dumbbells are unstable for all the potentials. The most stable SIA clusters are sets of parallel <111> crowdions. Large clusters of this type form

Yu. N. Osetsky; A. Serra; B. N. Singh; S. I. Golubov

2000-01-01

218

Solubilization of Cu 2+ from copper ore by iron-oxidizing bacteria isolated from the natural environment and identification of the enzyme that determines Cu 2+ solubilization activity  

Microsoft Academic Search

Solubilization of Cu2+ from copper concentrate by 67 strains of iron-oxidizing bacteria isolated from the natural environment was studied. In the case of static growth on copper concentrate (5%)-salt medium (pH 2.5) at 30°C, Cu2+ solubilization activities of 65 strains including Thiobacillus ferrooxidans strains AP19-3, OK-2, OK-3, OK1–50, Funis and NASF-1 ranged from 2.5–3.5 mg Cu2+\\/ml\\/33 d. In contrast, the

Tsuyoshi Sugio; Fauzia Akhter

1996-01-01

219

Rosette iron deficiency transcript and microRNA profiling reveals links between copper and iron homeostasis in Arabidopsis thaliana  

PubMed Central

Iron (Fe) is an essential plant micronutrient, and its deficiency limits plant growth and development on alkaline soils. Under Fe deficiency, plant responses include up-regulation of genes involved in Fe uptake from the soil. However, little is known about shoot responses to Fe deficiency. Using microarrays to probe gene expression in Kas-1 and Tsu-1 ecotypes of Arabidopsis thaliana, and comparison with existing Col-0 data, revealed conserved rosette gene expression responses to Fe deficiency. Fe-regulated genes included known metal homeostasis-related genes, and a number of genes of unknown function. Several genes responded to Fe deficiency in both roots and rosettes. Fe deficiency led to up-regulation of Cu,Zn superoxide dismutase (SOD) genes CSD1 and CSD2, and down-regulation of FeSOD genes FSD1 and FSD2. Eight microRNAs were found to respond to Fe deficiency. Three of these (miR397a, miR398a, and miR398b/c) are known to regulate transcripts of Cu-containing proteins, and were down-regulated by Fe deficiency, suggesting that they could be involved in plant adaptation to Fe limitation. Indeed, Fe deficiency led to accumulation of Cu in rosettes, prior to any detectable decrease in Fe concentration. ccs1 mutants that lack functional Cu,ZnSOD proteins were prone to greater oxidative stress under Fe deficiency, indicating that increased Cu concentration under Fe limitation has an important role in oxidative stress prevention. The present results show that Cu accumulation, microRNA regulation, and associated differential expression of Fe and CuSOD genes are coordinated responses to Fe limitation.

Waters, Brian M.; Stein, Ricardo J.

2012-01-01

220

Iron Absorption by Infants.  

National Technical Information Service (NTIS)

The research team studied absorption of iron from carefully selected iron-fortified foods that are now commercially available or are attractive candidates for future iron fortification. Because of possible adverse interactions with zinc and copper when in...

S. J. Fomon

1995-01-01

221

Abundant, seasonally variable supply of glacier flour-derived iron drives high nitrate consumption in Copper River plume and adjacent Gulf of Alaska continental shelf  

NASA Astrophysics Data System (ADS)

Recent work has suggested that high iron supply may contribute to a northward increase in phytoplankton biomass along the U.S. west coast, consistent with “bottom-up” control of these coastal ecosystems. We examine this hypothesis in waters of the Copper River plume and nearby continental shelf in the northern Gulf of Alaska (GoA). These are the first data we know of examining “bottom up” control of this coastal ecosystem by the supply of nitrate and iron. These are also the first data we know of that examine seasonal variability in the mechanisms that supply iron to this region, and in the iron concentrations. High concentrations (several hundred nM) of “total dissolveable” Fe (unfiltered, pH ~2) were present in surface waters spanning the continental shelf in early April 2010, from resuspension of fine glacial flour. Concentrations decreased dramatically beyond the shelf break. This fine particulate matter represents a large source of “dissolved” Fe to these waters. Surface-water nitrate concentrations were fairly uniform (~15 uM) across the entire shelf at this time, due to deep winter mixing. By late July this shelf particulate Fe source is greatly diminished, owing to strong stratification. Yet there is abundant “total dissolveable” Fe (several mM) at this time from the Copper River plume (largest single freshwater source to the GoA) and lower (several hundred nM) concentrations in the AK coastal current (that reflect the cumulative impact of melting glaciers from further south). By late July this abundant supply of iron in the Copper River vicinity, together with strong stratification, lead to complete consumption of surface-water nitrate across the entire shelf (and extending tens of km beyond the shelf). These data are consistent with the idea that high primary productivity in this region is fueled by abundant wintertime surface-water nitrate, together with iron supply from fine, labile, glacier-derived particulate matter from seasonally variable sources.

Crusius, J.; Schroth, A. W.; Campbell, R. W.; Nielsen, J. L.; Hoyer, I. R.; Brooks, W.

2010-12-01

222

Elevated copper in the amyloid plaques and iron in the cortex are observed in mouse models of Alzheimer's disease that exhibit neurodegeneration  

PubMed Central

BACKGROUND In Alzheimer’s disease (AD), alterations in metal homeostasis, including the accumulation of metal ions in the plaques and an increase of iron in the cortex, have been well documented but the mechanisms involved are poorly understood. OBJECTIVE In this study, we compared the metal content in the plaques and the iron speciation in the cortex of three mouse models, two of which show neurodegeneration (5xFAD and Tg-SwDI/NOS2?/? (CVN) and one that shows very little neurodegeneration (PSAPP). METHODS The Fe, Cu, and Zn contents and speciation were determined using synchrotron X-ray fluorescence microscopy (XFM) and X-ray absorption spectroscopy (XAS), respectively. RESULTS In the mouse models with reported significant neurodegeneration, we found that plaques contained ~25% more copper compared to the PSAPP mice. The iron content in the cortex increased at the late stage of the disease in all mouse models, but iron speciation remains unchanged. CONCLUSIONS The elevation of copper in the plaques and iron in the cortex is associated with AD severity, suggesting that these redox-active metal ions may be inducing oxidative damage and directly influencing neurodegeneration.

Bourassa, Megan W.; Leskovjan, Andreana C.; Tappero, Ryan V.; Farquhar, Erik R.; Colton, Carol A.; Van Nostrand, William E.; Miller, Lisa M.

2014-01-01

223

Modulation of copper toxicity-induced oxidative damage by excess supply of iron in maize plants  

Microsoft Academic Search

In this study, we examined the modulation of Cu toxicity-induced oxidative stress by excess supply of iron in Zea mays L. plants. Plants receiving excess of Cu (100 ?M) showed decreased water potential and simultaneously showed wilting in the\\u000a leaves. Later, the young leaves exhibited chlorosis and necrotic scorching of lamina. Excess of Cu suppressed growth, decreased\\u000a concentration of chloroplastic pigments

Praveen Kumar; Rajesh Kumar Tewari; Parma Nand Sharma

2008-01-01

224

Beta barium borate (BBO)  

Microsoft Academic Search

The paper contains a review of crystallographic, optical and nonlinear optical properties of beta barium borate (ß-BaB2O4 or BBO) crystal and presents a description of its typical applications in nonlinear optics and quantum electronics.

D. N. Nikogosyan

1991-01-01

225

Controlling barium sulfate  

Microsoft Academic Search

Even though for several years success has been realized in controlling barium sulfate scale deposition in relatively shallow, low pressure oil wells--by squeezing an organic phosphonate scale inhibitor into the producing zone--barium sulfate scale depositon in deep, high pressure\\/high temperature wells usually meant an expensive workover operation. A case history of a deep (16,000 ft) well in St. Mary Parish,

Greenley

2009-01-01

226

Removal and preconcentration of lead (II), copper (II), chromium (III) and iron (III) from wastewaters by surface developed alumina adsorbents with immobilized 1-nitroso-2-naphthol  

Microsoft Academic Search

The potential removal and preconcentration of lead (II), copper (II), chromium (III) and iron (III) from wastewaters were investigated and explored. Three new alumina adsorbents of acidic, neutral and basic nature (I–III) were synthesized via physical adsorption and surface loading of 1-nitroso-2-naphthol as a possible chelating ion-exchanger. The modified alumina adsorbents are characterized by strong thermal stability as well as

Mohamed E. Mahmoud; Maher M. Osman; Osama F. Hafez; Essam Elmelegy

2010-01-01

227

Welding procedure specification: gas tungsten arc welding of nickel-copper to nickel-chromium-iron. Supplement 1. Records of procedure qualification tests  

SciTech Connect

Procedure WPS-2303-ASME-3 is qualified under Section IX of the ASME Boiler and Pressure Vessel Code for gas tungsten arc welding of nickel-copper N04400 (P-42) to nickel-chromium-iron N06600 (P-43), in thickness range of 0.035 to 0.432 inch; filler metal is ERNiCu-7 (F-42); shielding gas is argon.

Wodtke, C.H.; Frizzell, D.R.; Plunkett, W.A.

1986-06-01

228

Determination of Copper, Iron, Nickel, and Zinc in Ethanol Fuel by Flame Atomic Absorption Spectrometry Using On?Line Preconcentration System  

Microsoft Academic Search

In this work, an on?line system for preconcentration and determination of copper, iron, nickel, and zinc at µg L level by flame atomic absorption spectrometry (FAAS) has been developed. Amberlite XAD?4 functionalized with 3,4?dihydroxybenzoic acid packed in a minicolumn was used as metal sorbent. The retained metals can be quickly eluted from sorbent material, with the eluent stream consisting of hydrochloric

Leonardo S. G. Teixeira; Marcos de A. Bezerra; Valfredo A. Lemos; Hilda C. dos Santos; Djane S. de Jesus; Antônio C. S. Costa

2005-01-01

229

Manganese, copper, zinc, iron, cadmium, mercury and lead in muscle meat, liver and kidneys of poultry, rabbit and sheep slaughtered in the northern part of Poland, 1987  

Microsoft Academic Search

Manganese, copper, zinc, iron, cadmium, mercury and lead concentrations have been determined in muscle meat, livers and kidneys of ducks, geese, chickens, hens, rabbits and sheep slaughtered in the northern part of Poland in 1987. The mean values obtained related to wet weight for muscle meat, livers and kidneys of animals were: 0.11–0.27, 0.73–3.3 and 0.90–1.9 mg\\/kg Mn; 0.52–7.3, 3.8–88

J. Falandysz

1991-01-01

230

Distribution of Copper, Iron, and Zinc in Biological Samples (Scalp Hair, Serum, Blood, and Urine) of Pakistani Viral Hepatitis (A–E) Patients and Controls  

Microsoft Academic Search

The aim of the present study was to compare the level of copper (Cu), iron (Fe) and zinc (Zn) in biological samples (serum,\\u000a blood, urine, and scalp hair) of patients suffering from different viral hepatitis (A, B, C, D, and E; n?=?521) of both gender age ranged 31–45 years. For comparative study, 255 age-matched control subjects, of both genders residing\\u000a in

Nida Fatima Kolachi; Tasneem Gul Kazi; Hassan Imran Afridi; Naveed Kazi; Ghulam Abbas Kandhro; Abdul Qadir Shah; Jameel Ahmed Baig; Sham Kumar Wadhwa; Sumaira Khan; Faheem Shah; Mohammad Khan Jamali; Mohammad Balal Arain

231

Effect of Dietary Calcium and Phosphorus Levels on the Utilization of Iron, Copper, and Zinc by Adult Males1-2  

Microsoft Academic Search

Iron, copper, and zinc utilization were examined in nine adult males fed a moderate calcium-moderate phosphorus diet (MCaMP), a moderate calcium-high phosphorus diet (MCaHP), and a high calcium-high phosphorus diet (HCaHP) during a 39-day balance study. The moderate and high calcium diets contained 780 mg and 2382 mg calcium daily, respectively. The moderate and high phosphorus diets contained 843 and

SUZANNE M. SNEDEKER; J. L. GREGER

232

Determination of copper, lead and iron in water and food samples after column solid phase extraction using 1-phenylthiosemicarbazide on Dowex Optipore L-493 resin  

Microsoft Academic Search

A novel solid phase extraction procedure for determination of copper, lead and iron in natural water and food samples has been established in the presented work. 1-Phenylthiosemicarbazide (1-PTSC) as ligand and Dowex Optipore L-493 resin as adsorbent were used in a mini chromatographic column. Various analytical conditions for the quantitative recoveries of analyte ions including pH, amounts of adsorbent, eluent,

Ozden Y?ld?z; Demirhan Citak; Mustafa Tuzen; Mustafa Soylak

2011-01-01

233

Column Solid Phase Extraction of Copper, Iron, and Zinc Ions at Trace Levels in Environmental Samples on Amberlite XAD?7 for Their Flame Atomic Absorption Spectrometric Determinations  

Microsoft Academic Search

A column solid?phase extraction method for the separation and preconcentration of copper, zinc, and iron at trace levels has been established prior to their flame atomic absorption spectrometric determinations. Analytes from 0.5 M KSCN in a 1 M HCl solution were recovered using of an Amberlite XAD?7 column. The chemical variables affecting the analytical performance of the combined methodology including reagent amounts,

Mustafa Tuzen; Mustafa Soylak; Latif Elci; Mehmet Dogan

2004-01-01

234

Copper and iron-pillared clay catalysts for the WHPCO of model and real wastewater streams from olive oil milling production  

Microsoft Academic Search

The properties of copper-based pillared clays (Cu-PILC) have been studied and compared with those of the analogous iron-based clays (Fe-PILC) in the wet hydrogen peroxide catalytic oxidation (WHPCO) of model phenolic compounds (p-coumaric and p-hydroxybenzoic acids) and real olive oil milling wastewater (OMW). These two catalysts show comparable performances in all these reactions, although they show some differences in the

Simona Caudo; Gabriele Centi; Chiara Genovese; Siglinda Perathoner

2007-01-01

235

Coumarin-based fluorescent probes for dual recognition of copper(II) and iron(III) ions and their application in bio-imaging.  

PubMed

Two new coumarin-based "turn-off" fluorescent probes, (E)-3-((3,4-dihydroxybenzylidene)amino)-7-hydroxy-2H-chromen-2-one (BS1) and (E)-3-((2,4-dihydroxybenzylidene)amino)-7-hydroxy-2H-chromen-2-one (BS2), were synthesized and their detection of copper(II) and iron(III) ions was studied. Results show that both compounds are highly selective for Cu²? and Fe³? ions over other metal ions. However, BS2 is detected directly, while detection of BS1 involves a hydrolysis reaction to regenerate 3-amino-7-hydroxycoumarin (3) and 3,4-dihydroxybenzaldehyde, of which 3 is able to react with copper(II) or iron(III) ions. The interaction between the tested compounds and copper or iron ions is associated with a large fluorescence decrease, showing detection limits of ca. 10?? M. Preliminary studies employing epifluorescence microscopy demonstrate that Cu²? and Fe³? ions can be imaged in human neuroblastoma SH-SY5Y cells treated with the tested probes. PMID:24419164

García-Beltrán, Olimpo; Cassels, Bruce K; Pérez, Claudio; Mena, Natalia; Núñez, Marco T; Martínez, Natalia P; Pavez, Paulina; Aliaga, Margarita E

2014-01-01

236

Structural features and the reaction mechanism of cytochrome oxidase: iron and copper X-ray absorption fine structure.  

PubMed Central

X-ray edge absorption of copper and extended fine structure studies of both copper and iron centers have been made of cytochrome oxidase from beef heart, Paracoccus dentrificans, and HB-8 thermophilic bacteria (1-2.5 mM in heme). The desired redox state (fully oxidized, reduced CO, mixed valence formate and CO) in the x-ray beam was controlled by low temperature (-140 degrees C) and was continuously monitored by simultaneous optical spectroscopy and by electron paramagnetic resonance (EPR) monitoring every 30 min of x-ray exposure. The structure of the active site, a cytochrome a3-copper pair in fully oxidized and in mixed valence formate states where they are spin coupled, contains a sulphur bridge with three ligands 2.60 +/- 0.03 A from Fea3 and 2.18 +/- 0.03 A from Cua3. The distance between Fea3 and Cua3 is 3.75 +/- 0.05 A, making the sulphur bond angle 103 degrees reasonable for sp3 sulphur bonding. The Fea3 first shell has four typical heme nitrogens (2.01 +/- 0.03 A) with a proximal nitrogen at 2.14 +/- 0.03 A. The sixth ligand is the bridging sulphur. The Cua3 first shell is identical to oxidized stellacyanin containing two nitrogens and a bridging sulphur. Upon reduction with CO, the active site is identical to reduced stellacyanin for the Cua3 first shell and contains the sulphur that forms the bridge in fully oxidized and mixed valence formate states. The Fea3 first shell is identical to oxyhemoglobin but has CO instead of O2. The other redox centers, Fea and the other "EPR detectable" Cu are not observed in higher shells of Fea3. Fea has six equidistant nitrogens and Cua has one (or two) nitrogens and three (or two) sulphurs with typical distances; these ligands change only slight on reduction. These structures afford the basis for an oxygen reduction mechanism involving oxy- and peroxy intermediates. Images FIGURE 2

Powers, L; Chance, B; Ching, Y; Angiolillo, P

1981-01-01

237

Nickel-cobalt-iron-copper sulfides and arsenides in solution-collapse breccia pipes, northwestern Arizona  

SciTech Connect

An extensive suite of Ni-Co-Fe-Cu sulfides and arsenides lies within the matrix of solution-collapse breccias buried deep within the plateaus of the Grand Canyon region. Ceilings over large caverns in the Redwall collapsed, brecciating the overlying sandstone and forming cylindrical breccia pipes up to 300 ft in diameter that extend vertically as much as 3,000 ft. These highly permeable breccias served as a host for the precipitation of a suite of over 100 minerals, including uraninite, sphalerite, galena and various copper phases, in addition to the Ni-Co-bearing-phase discussed here. Intricately zoned crystals of small (<1 mm), euhedral Ni-Co-Fe-As-S minerals were the first to form during the second major episode of mineralization in these pipes. Several of these phases replace minerals, such as barite and anhydrite, from the first episode. Extensive microprobe work has been done on samples from two breccia pipe mines, the Hack 2 and Orphan, which are about 50 miles apart. Mineral compositions are similar except that no copper is found in the Ni-Co-Fe phases from the Hack 2 mine, while pyrites containing 1 wt % Cu are common from the Orphan, which was mined for copper. In some of these pyrites', Cu is dominant and the mineral is actually villamaninite. Pyrites from both mines characteristically contain 0.5 to 3 wt % As. Metal contents in zones pyrite-bravoite-vaesite (M[sub 1]S[sub 2]) crystals at the Hack 2 mine range from Fe[sub 1] to Fe[sub .12], Ni[sub 0] to Ni[sub .86], and Co[sub 0] to Co[sub .10]. The metal content for polydymite-siegenite-violarite averages about (Ni[sub 2.33]Co[sub .39]Fe[sub .23])(S[sub 3.9]As[sub .1]). Orphan mine pyrite-bravoite-vaesite-villamaninite ranges in composition from pure FeS[sub 2] to (Ni[sub .6]Fe[sub .21]Co[sub .17])S[sub 2], and (Cu[sub .46]Ni[sub .27]Fe[sub .21]Co[sub .13])S[sub 2]. Of all the sulfides or arsenides found in these breccia pipes, only nickeline consistently occurs as the pure end member.

Wenrich, K.J. (Geological Survey, Denver, CO (United States)); Hlava, P.F. (Sandia National Labs., Albuquerque, NM (United States))

1993-04-01

238

Enthalpies of formation of borides of iron, cobalt, and nickel by solution calorimetry in liquid copper  

Microsoft Academic Search

The enthalpies of formation at 1385 ?2 K of the following crystalline borides have been determined by high temperature solution\\u000a calorimetry using liquid copper as the calorimetric solvent. Fe2B-67.87 ?8.05 kJ mol?1, Co2B -58.1 ?7.0 kJ mol?1, Ni2B -67.66 ?4.12 kJ ml?1, FeB-64.63 ?4.34 kJ mol?1, CoB -69.52 ?6.0 kJ mol?1, and NiB -40.2 ?3.77 kJ mol?1. The enthalpy of

Seichi Sato; O. J. Kleppa

1982-01-01

239

Synthesis and properties of ternary GIC with iron or copper chlorides  

NASA Astrophysics Data System (ADS)

The variety of graphite intercalation compounds (GIC) is provided by the possibility to obtain ternary intercalation (TGIC) compounds containing two or more intercalates. A wide range of metal chlorides (FeCl3, AlCl3, CuCl2, NiCl2) and Brönsted acids (HNO3, CH3COOH, H2SO4) are generally used as intercalates. Iron chloride intercalation into the graphite leads to the formation of binary GIC with composition C6nFeCl3. Iron chloride acts as intercalate and oxidizer for the graphite matrix. Oxidation ability is due to the evolving of chlorine gas. Intercalation of CuCl2 requires harder conditions and occurs only with Cl2 presence. Co-intercalation GICs with FeCl3 and CH3COOH were synthesized by electrochemical graphite oxidation in the mixed electrolyte. Bi-intercalation GICs containing CuCl2 and H2SO4 were obtained by successive graphite intercalation with metal chloride and acid. All the synthesized compounds were investigated by physicochemical analysis. New ternary intercalation compounds with the FeCl3 CH3COOH mixture or CuCl2 H2SO4 one were synthesized. The correlation between intercalation features and reagents intercalation ability was shown.

Shornikova, O. N.; Dunaev, A. V.; Maksimova, N. V.; Avdeev, V. V.

2006-05-01

240

Interaction of copper with iron, iodine, and thyroid hormone status in goitrous patients.  

PubMed

In many developing countries, men and women are at high risk of goiter and iron deficiency. The aim of the recent study is to assess the interaction of (Cu), with iron (Fe), iodine/iodide (I), and thyroid hormones in goitrous patients. Sixty goitrous male (GMPs) and 72 female patients (GFPs) were evaluated for the Cu, Fe, I, and thyroid hormones status in biological samples (serum and urine), and compared to non-goitrous subjects of both genders (M = 106, F = 120). The biological samples were analyzed for Cu and Fe concentration using atomic absorption spectrometer, while I was measured by the potentiometric method, prior to microwave-assisted acid digestion (MD). Quality control for the method was established with certified samples. Significantly higher mean values of Cu in serum, and urine samples of GMPs and GFPs, while lower value of Fe and I were observed as compared to control subjects (p < 0.015), respectively. The mean values of free triiodothyronine (FT3) and free thyroxin (FT4) were found to be lower in goitrous patients of both genders than in the age-matched healthy controls (p < 0.006 and 0.002), respectively, in contrast high mean values of thyroid-stimulating hormone (TSH) were detected in patients (p < 0.009), as compared to non-goitrous subjects. It was observed that the deficiencies of Fe, I, and thyroid hormone in goitrous patients could be influenced by efficiency of Cu. PMID:19693445

Kazi, Tasneem Gul; Kandhro, Ghulam Abbas; Afridi, Hassan Imran; Kazi, Naveed; Baig, Jameel Ahmed; Arain, Mohammad Balal; Shah, Abdul Qadir; Syed, Nasreen; Kumar, Sham; Kolachi, Nida Fatima; Khan, Sumaira

2010-06-01

241

Electrochromic multilayer films of tunable color by combination of copper or iron complex and monolacunary dawson-type polyoxometalate.  

PubMed

Electrochromic multilayer films consisting of polyoxometalate (POM) cluster alpha-K(10)[P(2)W(17)O(61)].17H(2)O (P(2)W(17)), copper(II) complex [Cu(II)(phen)(2)](NO(3))(2) (phen = 1,10-phenithroline), and iron complex [Fe(II)(phen)(3)](ClO(4))(2) were fabricated on silicon, quartz and ITO substrates by layer-by-layer self-assembly method. The multilayer films, PSS/Cu(II)(phen)(2)/[(P(2)W(17)/Cu(II)(phen)(2))](n) and PSS/Fe(II)(phen)(3)/[(P(2)W(17)/Fe(II) (phen)(3))](n) were characterized by UV-vis spectra, X-ray photoelectron spectra, cyclic voltammetry (CV), chronoamperometric (CA) and in-situ spectral electrochemical measurements. The interesting feature of the electrochromic film is its adjustable color by reduction of both transition metal complex and polyoxometalate at different potentials. The multilayer films also exhibit high optical contrast, suitable response time and low operation potential due to the presence of mono-lacunary-substituted polyoxometalate and transition metal complex. This is the first example that the color of electrochromic film can be adjustable, which gives valuable information for exploring new electrochromic materials with tunable colors. PMID:16852064

Gao, Guanggang; Xu, Lin; Wang, Wenju; An, Wenjia; Qiu, Yunfeng; Wang, Zhenqing; Wang, Enbo

2005-05-12

242

Low Serum Levels of Zinc, Copper, and Iron as Risk Factors for Osteoporosis: a Meta-analysis.  

PubMed

Zinc (Zn), copper (Cu), and iron (Fe) are essential trace elements for the growth, development, and maintenance of healthy bones. However, there are conflicting reports as to the relationship between serum level of Zn, Cu, or Fe and osteoporosis (OP). The purpose of the present study is to clarify the relationship between serum Zn, Cu, or Fe and OP using a meta-analysis approach. We searched all articles indexed in PubMed published up to May 2014 concerning the association between serum level of Zn, Cu, or Fe and OP. Eight eligible articles involving 2,188 subjects were identified. Overall, pooled analysis indicated that patients with OP had a lower serum level of Zn, Cu, or Fe than the healthy controls (Zn standardized mean difference (SMD)?=?-1.396, 95 % confidence interval (CI)?=?[-2.129, -0.663]; Cu SMD?=?-0.386, 95 % CI?=?[-0.538, -0.234]; Fe SMD?=?-0.22, 95 % CI?=?[-0.30, -0.13]). Further subgroup analysis found that geographical location and gender had an influence on the serum level of Zn in OP and healthy controls, but not on the serum level of Cu or Fe. No evidence of publication bias was observed. In conclusion, this meta-analysis suggests that low serum levels of Zn, Cu, and Fe seem to be important risk factors for OP and well-designed studies with adequate control for confounding factors are required in future investigations. PMID:24908111

Zheng, Jianmao; Mao, Xueli; Ling, Junqi; He, Qun; Quan, Jingjing

2014-07-01

243

Flow-injection simultaneous determination of iron(III) and copper(II) and of iron(III) and palladium(II) based on photochemical reactions of thiocyanato-complexes.  

PubMed

The flow injection analysis systems have been developed for the simultaneous determination of iron(III) and copper(II) and of iron(III) and palladium(II) based on the photochemical reactions of their thiocyanato-complexes. In the first system, a sample solution was injected in to nitric acid solution and mixed with ammonium thiocyanate solution, followed by spectrophotometric monitoring of the thiocyanato-complexes formed. Another aliquot of the same sample solution was injected and the thiocyanato-complexes formed in the same way were irradiated by UV light before spectrophotometric monitoring. In another system, the absorbance of thiocyanato-complexes formed by each sample injection was monitored with two flow cells aligned with the same optical path before and after UV irradiation. The difference in the extent of photochemical decomposition of the thiocyanato-complexes enabled simultaneous determinations of iron(III) and copper(II) and of iron(III) and palladium(II) at levels of several mugml(-1) to some tens mugml(-1) in their admixtures. Sample throughputs are 40 and 20 h(-1) by the former and latter systems, respectively. PMID:18968842

Oguma, Koichi; Yoshioka, Osamu

2002-12-01

244

Proteins involved in iron metabolism in beef cattle are affected by copper deficiency in combination with high dietary manganese, but not by copper deficiency alone.  

PubMed

A 493-d study was conducted to determine the impact of a severe, long-term Cu deficiency on Fe metabolism in beef cattle. Twenty-one Angus calves were born to cows receiving one of the following treatments: 1) adequate Cu (+Cu), 2) Cu deficient (-Cu), and 3) Cu deficient plus high Mn (-Cu+Mn). Copper deficiency was induced through the addition of 2 mg of Mo/kg of DM. After weaning, calves remained on the same treatment as their dam through growing (basal diet analyzed 7 mg of Cu/kg of DM) and finishing (analyzed 4 mg of Cu/kg of DM) phases. Plasma Fe concentrations were positively correlated (P < 0.01; r = 0.49) with plasma Cu concentrations. Liver Fe concentrations were greater (P = 0.05) in -Cu vs. +Cu calves and further increased (P = 0.07) in -Cu+Mn vs. -Cu calves. There was a negative relationship (P < 0.01; r = -0.31) between liver Cu and Fe concentrations. This relationship is likely explained by less (P < 0.01) plasma ceruloplasmin activity in -Cu than +Cu calves. As determined by real-time reverse transcription-PCR, relative expression of hepatic hepcidin was significantly downregulated (>1.5 fold) in -Cu compared with +Cu calves (P = 0.03), and expression of hepatic ferroportin tended (P = 0.09) to be downregulated in -Cu vs. +Cu. In the duodenum, ferritin tended to be upregulated in -Cu. vs. +Cu calves (P < 0.06). No significant change (P > 0.2) due to Cu-deficiency was detected at the transcriptional level for either isoform of divalent metal transporter 1 (DMT1 mRNA with or without an iron responsive element; dmt1IRE and dmt1-nonIRE) in liver or intestine. Duodenal expression of hephaestin and ferroportin protein was not affected by dietary treatment (P > 0.20). However, duodenal expression of DMT1 protein was less (P = 0.04) in -Cu+Mn steers vs. -Cu steers. In summary, Cu deficiency alone did affect hepatic gene expression of hepcidin and ferroportin, but did not affect duodenal expression of proteins important in Fe metabolism. However, the addition of 500 mg of Mn/kg of DM to a diet low in Cu reduced duodenal expression of the Fe import protein DMT1. PMID:19820055

Hansen, S L; Trakooljul, N; Liu, H-C S; Hicks, J A; Ashwell, M S; Spears, J W

2010-01-01

245

Microstructural Evolution and Mechanical Properties of Fusion Welds in an Iron-Copper-Based Multicomponent Steel  

NASA Astrophysics Data System (ADS)

NUCu-140 is a copper-precipitation-strengthened steel that exhibits excellent mechanical properties with a relatively simple chemical composition and processing schedule. As a result, NUCu-140 is a candidate material for use in many naval and structural applications. Before NUCu-140 can be implemented as a replacement for currently used materials, the weldability of this material must be determined under a wide range of welding conditions. This research represents an initial step toward understanding the microstructural and mechanical property evolution that occurs during fusion welding of NUCu-140. Microhardness traverses and tensile testing using digital image correlation show local softening in the heat-affected zone (HAZ). Microstructural characterization using light optical microscopy (LOM) revealed very few differences in the softened regions compared with the base metal. Local-electrode atom-probe (LEAP) tomography demonstrates that local softening occurs as a result of dissolution of the Cu-rich precipitates. MatCalc kinetic simulations (Vienna, Austria) were combined with welding heat-flow calculations to model the precipitate evolution within the HAZ. Reasonably good agreement was obtained between the measured and calculated precipitate radii, number density, and volume fraction of the Cu-rich precipitates in the weld. These results were used with a precipitate-strengthening model to understand strength variations within the HAZ.

Farren, Jeffrey D.; Hunter, Allen H.; Dupont, John N.; Seidman, David N.; Robino, Charles V.; Kozeschnik, Ernst

2012-11-01

246

Evaluation of different column types for the hydrophilic interaction chromatographic separation of iron-citrate and copper-histidine species from plants.  

PubMed

Hydrophilic interaction chromatography (HILIC) has emerged as a very useful separation method for polar analytes, including non-covalent metal species. Several types of stationary phases are available for HILIC applications, differing mainly in their chemical functionalities that supply additional interaction modes and alternative selectivities for the separation of special analytes. With regard to the separation of metal species only few of these stationary phases have been applied to date, and it is not completely clear what are their differences with respect to the chromatographic separation of metal species, but also with respect to species stability during chromatography. Here, a comparison of different column types for the HILIC separation of iron citrate and copper histidine species is presented and the results are discussed with respect to retention mechanisms and chromatographic stability of these metal species. It is shown that different stationary phases display very different separation patterns. In particular, three types of HILIC columns enable successful separation of iron citrates and copper histidine at pH 5.5, namely a crosslinked diol phase, a zwitterionic phase, and an amide phase. Two groups of iron-citrates are separated on all three columns, consisting of a species of 3:3 stoichiometry and another one of mainly 3:4 stoichiometry (plus 1:2 and 2:2 species). For copper-histidine only one stable species is found based on the 1:2 stoichiometry. Detection and unambiguous identification of the different species is possible by employing electrospray mass spectrometry in the negative ionization mode. Species found in standard solutions are consistent with species found in spiked plant samples. Also in unspiked solutions iron citrate of 3:4 stoichiometry (plus 1:2 and 2:2) is detectable, but no species of 3:3 stoichiometry. Significant differences of related species patterns are found in real plant samples. PMID:21474140

Köster, Jessica; Shi, Rongli; von Wirén, Nicolaus; Weber, Günther

2011-07-29

247

Observed Barium Emission Rates  

NASA Technical Reports Server (NTRS)

The barium releases from the CRRES satellite have provided an opportunity for verifying theoretically calculated barium ion and neutral emission rates. Spectra of the five Caribbean releases in the summer of 1991 were taken with a spectrograph on board a U.S. Air Force jet aircraft. Because the line of sight release densities are not known, only relative rates could be obtained. The observed relative rates agree well with the theoretically calculated rates and, together with other observations, confirm the earlier detailed theoretical emission rates. The calculated emission rates can thus with good accuracy be used with photometric observations. It has been postulated that charge exchange between neutral barium and oxygen ions represents a significant source for ionization. If so. it should be associated with emissions at 4957.15 A and 5013.00 A, but these emissions were not detected.

Stenbaek-Nielsen, H. C.; Wescott, E. M.; Hallinan, T. J.

1993-01-01

248

Inductively coupled plasma atomic fluorescence spectrometric determination of cadmium, copper, iron, lead, manganese and zinc  

USGS Publications Warehouse

An inductively coupled plasma atomic fluorescence spectrometric method is described for the determination of six elements in a variety of geological materials. Sixteen reference materials are analysed by this technique to demonstrate its use in geochemical exploration. Samples are decomposed with nitric, hydrofluoric and hydrochloric acids, and the residue dissolved in hydrochloric acid and diluted to volume. The elements are determined in two groups based on compatibility of instrument operating conditions and consideration of crustal abundance levels. Cadmium, Cu, Pb and Zn are determined as a group in the 50-ml sample solution under one set of instrument conditions with the use of scatter correction. Limitations of the scatter correction technique used with the fluorescence instrument are discussed. Iron and Mn are determined together using another set of instrumental conditions on a 1-50 dilution of the sample solution without the use of scatter correction. The ranges of concentration (??g g-1) of these elements in the sample that can be determined are: Cd, 0.3-500; Cu, 0.4-500; Fe, 85-250 000; Mn, 45-100 000; Pb, 5-10 000; and Zn, 0.4-300. The precision of the method is usually less than 5% relative standard deviation (RSD) over a wide concentration range and acceptable accuracy is shown by the agreement between values obtained and those recommended for the reference materials.

Sanzolone, R. F.

1986-01-01

249

Adsorption of nickel and copper onto natural iron oxide-coated sand from aqueous solutions: study in single and binary systems.  

PubMed

Natural iron oxide-coated sand (NCS), extracted from the iron ore located in North-West of Tunisia, was employed to investigate its capacity to remove copper and nickel from aqueous solutions. The aim of this work was to characterize the considered sorbent (NCS) and to assess the possibility of removing nickel and copper from aqueous solutions by this sorbent. The effects of agitation time, pH, initial metal ion concentration and temperature on the removal of these metals were studied. In order to study the sorption isotherm, two equilibrium models, the Freundlich and Langmuir isotherms, were analyzed. The effect of solution pH on the adsorption onto NCS was studied in the pH range from 2 to 7 and 2 to 9 for copper and nickel respectively. The adsorption was endothermic and the computation of the parameters, DeltaH degrees, DeltaS degrees and DeltaG degrees, indicated that the interactions were thermodynamically favourable. Experiments with Cu and Ni adsorption measured together showed that Cu severely interfered with Ni adsorption to the NCS and vice versa under the conditions of the two coexisted ions adsorption. PMID:18701213

Boujelben, N; Bouzid, J; Elouear, Z

2009-04-15

250

Antioxidant properties of carnosine re-evaluated with oxidizing systems involving iron and copper ions.  

PubMed

Carnosine has antioxidant properties and is efficient in the treatment of chemically-induced inflammatory lesions in animals. However, some studies question its biological significance as antioxidant and show lack of protection and even pro-oxidant effect of carnosine in systems containing nickel and iron ions. The ability of carnosine to: (1) reduce Fe(3+) into Fe(2+) ions; (2) protect deoxyribose from oxidation by Fe(2+)-, Fe(3+)-, and Cu(2+)-H(2)O(2)-EDTA systems; (3) protect DNA from damage caused by Cu(2+)-, and Fe(2+)-H(2)O(2)-ascorbate systems; (4) inhibit HClO- and H(2)O(2)-peroxidase-induced luminol dependent chemiluminescence was tested in vitro. At concentration 10 mM carnosine reduced 16.6+/-0.5 nmoles of Fe(3+) into Fe(2+) ions during 20 min. incubation and added to plasma significantly increased its ferric reducing ability. Inhibition of deoxyribose oxidation by 10 mM carnosine reached 56+/-5, 40+/-11 and 30+/-11% for systems containing Fe(2+), Fe(3+) and Cu(2+) ions, respectively. The damage to DNA was decreased by 84+/-9 and 61+/-14% when Cu(2+)-, and Fe(2+)-H(2)O(2)-ascorbate systems were applied. Combination of 10 mM histidine with alanine or histidine alone (but not alanine) enhanced 1.3 and 2.3 times (P<0.05) the DNA damage induced by Fe(2+)-H(2)O(2)-ascorbate. These amino acids added to 10 mM carnosine decreased 3.1-fold (P<0.05) its protective effect on DNA. Carnosine at 10 and 20 mM decreased by more than 90% light emission from both chemiluminescent systems. It is concluded that carnosine has significant antioxidant activity especially in the presence of transition metal ions. However, hydrolysis of carnosine with subsequent histidine release may be responsible for some pro-oxidant effects. PMID:15853927

Mozdzan, Monika; Szemraj, Janusz; Rysz, Jacek; Nowak, Dariusz

2005-05-01

251

Solid state 31phosphorus nuclear magnetic resonance of iron-, manganese-, and copper-containing synthetic hydroxyapatites  

NASA Technical Reports Server (NTRS)

The incorporation of micronutrients into synthetic hydroxyapatite (SHA) is proposed for slow release of these nutrients to crops in the National Aeronautics and Space Administration's (NASA's) Advanced Life Support (ALS) program for Lunar or Martian outposts. Solid state 31P nuclear magnetic resonance (NMR) was utilized to examine the paramagnetic effects of Fe3+, Mn2+, and Cu2+ to determine if they were incorporated into the SHA structure. Separate Fe3+, Mn2+, and Cu2+ containing SHA materials along with a transition metal free SHA (pure-SHA) were synthesized using a precipitation method. The proximity (<1 nm) of the transition metals to the 31P nuclei of SHA were apparent when comparing the integrated 31P signal intensities of the pure-SHA (87 arbitrary units g-1) with the Fe-, Mn-, and Cu-SHA materials (37-71 arbitrary units g-1). The lower integrated 31P signal intensities of the Fe-, Mn-, and Cu-SHA materials relative to the pure-SHA suggested that Fe3+, Mn2+, and Cu2+ were incorporated in the SHA structure. Further support for Fe3+, Mn2+, and Cu2+ incorporation was demonstrated by the reduced spin-lattice relaxation constants of the Fe-, Mn-, and Cu-SHA materials (T'=0.075-0.434s) relative to pure-SHA (T1=58.4s). Inversion recovery spectra indicated that Fe3+, Mn2+, and Cu2+ were not homogeneously distributed about the 31P nuclei in the SHA structure. Extraction with diethylene-triamine-penta-acetic acid (DTPA) suggested that between 50 and 80% of the total starting metal concentrations were incorporated in the SHA structure. Iron-, Mn-, and Cu-containing SHA are potential slow release sources of Fe, Mn, and Cu in the ALS cropping system.

Sutter, B.; Taylor, R. E.; Hossner, L. R.; Ming, D. W.

2002-01-01

252

Solid state 31phosphorus nuclear magnetic resonance of iron-, manganese-, and copper-containing synthetic hydroxyapatites.  

PubMed

The incorporation of micronutrients into synthetic hydroxyapatite (SHA) is proposed for slow release of these nutrients to crops in the National Aeronautics and Space Administration's (NASA's) Advanced Life Support (ALS) program for Lunar or Martian outposts. Solid state 31P nuclear magnetic resonance (NMR) was utilized to examine the paramagnetic effects of Fe3+, Mn2+, and Cu2+ to determine if they were incorporated into the SHA structure. Separate Fe3+, Mn2+, and Cu2+ containing SHA materials along with a transition metal free SHA (pure-SHA) were synthesized using a precipitation method. The proximity (<1 nm) of the transition metals to the 31P nuclei of SHA were apparent when comparing the integrated 31P signal intensities of the pure-SHA (87 arbitrary units g-1) with the Fe-, Mn-, and Cu-SHA materials (37-71 arbitrary units g-1). The lower integrated 31P signal intensities of the Fe-, Mn-, and Cu-SHA materials relative to the pure-SHA suggested that Fe3+, Mn2+, and Cu2+ were incorporated in the SHA structure. Further support for Fe3+, Mn2+, and Cu2+ incorporation was demonstrated by the reduced spin-lattice relaxation constants of the Fe-, Mn-, and Cu-SHA materials (T'=0.075-0.434s) relative to pure-SHA (T1=58.4s). Inversion recovery spectra indicated that Fe3+, Mn2+, and Cu2+ were not homogeneously distributed about the 31P nuclei in the SHA structure. Extraction with diethylene-triamine-penta-acetic acid (DTPA) suggested that between 50 and 80% of the total starting metal concentrations were incorporated in the SHA structure. Iron-, Mn-, and Cu-containing SHA are potential slow release sources of Fe, Mn, and Cu in the ALS cropping system. PMID:12088032

Sutter, B; Taylor, R E; Hossner, L R; Ming, D W

2002-01-01

253

Effects of copper, iron and fluoride co-crystallized with sugar on caries development and acid formation in deslivated rats.  

PubMed

The purpose was to explore the effects of combinations of copper, iron and fluoride (Cu, Fe and F) incorporated in sucrose by co-crystallization on caries development in the deslivated rat model and to examine acid formation by bacteria in the rat mouth. Ninety-six Sprague-Dawley rats were infected with Streptococcus sobrinus 6715 and desalivated when aged 26 days. Eight groups were placed in a König-Höfer programmed feeder and received 17 meals daily at hourly intervals, and essential nutrition (NCP No. 2) by gavage twice daily for 21 days. The groups received (1) plain sucrose, (2) F (8 parts/10(6)) co-crystallized with sucrose, (3) Fe (88 parts/10(6)) sucrose, (4) Cu (75 parts/10(6)) sucrose, (5) Cu + F sucrose, (6) Cu + L Fe sucrose, (7) F + Fe sucrose, and (8) Cu + Fe + F sucrose. At death the jaws were removed and sonicated in 0.9% saline solution for microbial assessment. In addition, organic acid assays were performed for each animal. Keyes smooth-surface and sulcal caries scores were lowest in the Cu + Fe + F sucrose group, but not statistically significantly different from those of the other Cu groups. The numbers of Strep. sobrinus found in the groups that received Cu, Cu + Fe, Cu + F, F + Fe and Cu + Fe + F sugar were lower than in the control group. Lactic acid was found in lower concentrations in Fe, Cu, Cu + F, Cu + Fe and F + Fe groups than in the other groups. It appears that combinations of Cu; Fe and F co-crystallized with sugar may have an additive effect in reducing the cariogenic potential of sugar by affecting lactic acid formation and reducing bacterial colonization. PMID:9068864

Rosalen, P L; Pearson, S K; Bowen, W H

1996-11-01

254

Zinc, Iron, Manganese and Copper Uptake Requirement in Response to Nitrogen Supply and the Increased Grain Yield of Summer Maize  

PubMed Central

The relationships between grain yields and whole-plant accumulation of micronutrients such as zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu) in maize (Zea mays L.) were investigated by studying their reciprocal internal efficiencies (RIEs, g of micronutrient requirement in plant dry matter per Mg of grain). Field experiments were conducted from 2008 to 2011 in North China to evaluate RIEs and shoot micronutrient accumulation dynamics during different growth stages under different yield and nitrogen (N) levels. Fe, Mn and Cu RIEs (average 64.4, 18.1and 5.3 g, respectively) were less affected by the yield and N levels. ZnRIE increased by 15% with an increased N supply but decreased from 36.3 to 18.0 g with increasing yield. The effect of cultivars on ZnRIE was similar to that of yield ranges. The substantial decrease in ZnRIE may be attributed to an increased Zn harvest index (from 41% to 60%) and decreased Zn concentrations in straw (a 56% decrease) and grain (decreased from 16.9 to 12.2 mg kg?1) rather than greater shoot Zn accumulation. Shoot Fe, Mn and Cu accumulation at maturity tended to increase but the proportions of pre-silking shoot Fe, Cu and Zn accumulation consistently decreased (from 95% to 59%, 90% to 71% and 91% to 66%, respectively). The decrease indicated the high reproductive-stage demands for Fe, Zn and Cu with the increasing yields. Optimized N supply achieved the highest yield and tended to increase grain concentrations of micronutrients compared to no or lower N supply. Excessive N supply did not result in any increases in yield or micronutrient nutrition for shoot or grain. These results indicate that optimized N management may be an economical method of improving micronutrient concentrations in maize grain with higher grain yield.

Xue, Yanfang; Yue, Shanchao; Zhang, Wei; Liu, Dunyi; Cui, Zhenling; Chen, Xinping; Ye, Youliang; Zou, Chunqin

2014-01-01

255

Estimation of copper and iron burden in biological samples of various stages of hepatitis C and liver cirrhosis patients.  

PubMed

There is accumulative evidence that the metabolism of iron (Fe) and copper (Cu) is altered in human due to infections, indicating that both elements have roles in pathogenesis and progress of viral diseases. In the present study, the correlation of Cu and Fe was evaluate in biological samples (serum and scalp hair) of hepatitis C (hepatitis C virus (HCV)) patients of both genders at different stages. For comparative study, the scalp hair and serum samples of healthy individuals of same age group (30-50 years) and socioeconomic status were collected. The biological samples were analyzed for Fe and Cu by atomic absorption spectroscopy after microwave-assisted acid digestion. The validity and accuracy of methodology were checked by certified reference materials of same matrixes. The levels of Cu and Fe in biological samples were enhanced in hepatic disorder patients, including acute (after diagnosis test, anti-HCV sero-positive) hepatic fibrosis and liver cirrhosis as compared to healthy referents. The difference was significant (p??0.1) except in the first stage of HCV (p?

Arain, Salma Aslam; Kazi, Tasneem G; Afridi, Hassan Imran; Talpur, Farah Naz; Mughal, Moina Akhtar; Shah, Faheem; Arain, Sadaf Sadia; Panhwar, Abdul Haleem

2014-08-01

256

New evidence on iron, copper accumulation and zinc depletion and its correlation with DNA integrity in aging human brain regions  

PubMed Central

Deoxyribonucleic acid (DNA) conformation and stability play an important role in brain function. Earlier studies reported alterations in DNA integrity in the brain regions of neurological disorders like Parkinson’s and Alzheimer’s diseases. However, there are only limited studies on DNA stability in an aging brain and the factors responsible for genomic instability are still not clear. In this study, we assess the levels of Copper (Cu), Iron (Fe) and Zinc (Zn) in three age groups (Group I: below 40 years), Group II: between 41-60 years) and Group III: above 61 years) in hippocampus and frontal cortex regions of normal brains. The number of samples in each group was eight. Genomic DNA was isolated and DNA integrity was studied by nick translation studies and presented as single and double strand breaks. The number of single strand breaks correspondingly increased with aging compared to double strand breaks. The strand breaks were more in frontal cortex compared to hippocampus. We observed that the levels of Cu and Fe are significantly elevated while Zn is significantly depleted as one progresses from Group I to Group III, indicating changes with aging in frontal cortex and hippocampus. But the elevation of metals was more in frontal cortical region compared to hippocampal region. There was a clear correlation between Cu and Fe levels versus strand breaks in aging brain regions. This indicates that genomic instability is progressive with aging and this will alter the gene expressions. To our knowledge, this is a new comprehensive database to date, looking at the levels of redox metals and corresponding strand breaks in DNA in two brain regions of the aging brain. The biological significance of these findings with relevance to mental health will be discussed.

Vasudevaraju, P.; Bharathi; T, Jyothsna; Shamasundar, N. M.; Subba Rao, K.; Balaraj, B. M.; KSJ, Rao; T.S, Sathyanarayana Rao

2010-01-01

257

Mechanism of copper transport at the blood-cerebrospinal fluid barrier: influence of iron deficiency in an in vitro model  

PubMed Central

Copper (Cu) is an essential trace element that requires tight homeostatic regulation to ensure appropriate supply while not causing cytotoxicity due to its strong redox potential. Our previous in vivo study has shown that iron deficiency (FeD) increases Cu levels in brain tissues, particularly in the choroid plexus, where the blood–cerebrospinal fluid (CSF) barrier resides. This study was designed to elucidate the mechanism by which FeD results in excess Cu accumulation at the blood–CSF barrier. The effect of FeD on cellular Cu retention and transporters Cu transporter-1 (Ctr1), divalent metal transporter 1 (DMT1), antioxidant protein-1 (ATOX1) and ATP7A was examined in choroidal epithelial Z310 cells. The results revealed that deferoximine treatment (FeD) resulted in 70% increase in cellular Cu retention (P < 0.05). A significant increase in the mRNA levels of DMT1, but not Ctr1, was also observed after FeD treatment, suggesting a critical role of DMT1 in cellular Cu regulation during FeD. Knocking down Ctr1 or DMT1 resulted in significantly lower Cu uptake by Z310 cells, whereas the knocking down of ATOX1 or ATP7A led to substantial increases of cellular retention of Cu. Taken together, these results suggest that Ctr1, DMT1, ATOX1 and ATP7A contribute to Cu transport at the blood–CSF barrier, and that the accumulation of intracellular Cu found in the Z310 cells during FeD appears to be mediated, at least in part, via the upregulation of DMT1 after FeD treatment.

Monnot, Andrew D; Zheng, Gang; Zheng, Wei

2014-01-01

258

Geomagnetic field intensity: How high can it get? How fast can it change? Constraints from Iron Age copper slag  

NASA Astrophysics Data System (ADS)

The intensity of the geomagnetic field varies over different time scales. Yet, constraints on the maximum intensity of the field as well as for its maximum rate of change are inadequate due to poor temporal resolution and large uncertainties in the geomagnetic record. The purpose of this study is to place firm limits on these fundamental properties by constructing a high-resolution archaeointensity record of the Levant from the 11th century to the early 9th century BCE, a period over which the geomagnetic field reached its maximum intensity in Eurasia over the past 50,000 years. We investigate a 14C-dated sequence of ten layers of slag material, which accumulated within an ancient industrial waste mound of an Iron Age copper-smelting site in southern Israel. Depositional stratigraphy constrains relative ages of samples analyzed for paleointensity, and 14C dates from different horizons of the mound constrain the age of the whole sequence. The analysis yielded 35 paleointenisty data points with accuracy better than 94% and precision better than 6%, covering a period of less than 350 years, most probably 200 years. We construct a new high-resolution quasi-continuous archaeointensity curve of the Levant that displays two dramatic spikes in geomagnetic intensity, each corresponding to virtual axial dipole moment (VADM) in excess of 200 ZAm 2. The geomagnetic spikes rise and fall over a period of less than 30 years and are associated with VADM fluctuations of at least 70 ZAm 2. Thus, the Levantine archaeomagnetic record places new constraints on maximum geomagnetic intensity as well as for its rate of change. Yet, it is not clear whether the geomagnetic spikes are local non-dipolar features or a geomagnetic dipolar phenomenon.

Shaar, Ron; Ben-Yosef, Erez; Ron, Hagai; Tauxe, Lisa; Agnon, Amotz; Kessel, Ronit

2011-01-01

259

Alterations of serum zinc, copper, manganese, iron, calcium, and magnesium concentrations and the complexity of interelement relations in patients with obsessive-compulsive disorder.  

PubMed

The purpose of the present study was to evaluate the status of serum trace elements: zinc, copper, manganese, iron, calcium, and magnesium concentrations in obsessive-compulsive disorder patients. Forty-eight obsessive-compulsive disorder patients and 48 healthy volunteers were included in this study. Patients were recruited from Bangabandhu Sheikh Mujib Medical University by random sampling. Serum trace element concentrations were determined using flame atomic absorption spectroscopy (for zinc, copper, iron, calcium, and magnesium) as well as graphite furnace atomic absorption spectroscopy (for manganese). Data were analyzed using independent t test, Pearson's correlation analysis, regression analysis, and ANOVA. Statistical analysis of these data showed a definite pattern of variation among certain elements in patients with obsessive-compulsive disorder compared to controls. In patients' serum, zinc, iron, and magnesium concentrations decreased significantly (p<0.05) compared to the controls. Serum manganese and calcium concentrations were significantly higher (p<0.05) in patients compared to the controls. These data showed a definite imbalance in the interelement relations in obsessive-compulsive disorder patients compared to controls and therefore suggest a disturbance in the element homeostasis. PMID:22383079

Shohag, Hasanuzzaman; Ullah, Ashik; Qusar, Shalahuddin; Rahman, Mustafizur; Hasnat, Abul

2012-09-01

260

Iron and copper isotope fractionation during filtration and ultrafiltration of boreal organic-rich waters  

NASA Astrophysics Data System (ADS)

Typical feature of all boreal surface waters is high concentration of dissolved (< 0.22 µm) organic matter (DOM) and iron, notably in the form of Fe(III)-OM complexes. Organic and organo-mineral colloids are the most likely carriers of trace metals such as Cu in rivers of the boreal zone. This work addresses colloidal speciation of Cu and Fe using conventional size separation technique, on-site frontal ultrafiltration. Specifically, we aimed to test the possibility of the presence of different pools of metal having specific isotopic signatures in different colloidal fractions using stable isotope measurements. We have chosen Cu for its high affinity to colloidal DOM and Fe for its tendency to form stable organo-mineral colloids of various size. Samples of natural waters were collected from small rivers, lakes, bogs, groundwater and soil environments in the Northern Karelia (NW Russia) during summer baseflow period. Large volumes (20-40 L) of water were filtered in the field through progressively decreasing pore size filters: 20, 10, 5, 0.8, 0.45, 0.22, 0.1 µm and 100, 10 and 1 kDa (1 kDa ~ 1 nm) using nylon and regenerated cellulose membranes and frontal ultrafiltration (Millipore, Amicon) devises. The homogeneity of the sample was verified by tracing radiogenic Sr isotopes in each fraction. In all filtrates and ultrafiltrates (permeates), and in selected retentates, stable isotopic composition of Cu and Fe was measured using double focusing high resolution MC-ICP MS (Neptune). We observe rather constant Cu isotopic ratio in all filtrate series and a systematic enrichment of heavy isotope of Fe with decreasing poresize. These preliminary results can be explained by strong complexation of Cu with small-size organic ligands of fulvic nature and its partial association with organo-mineral colloids. Both Fe(III) - OM complxeation and Fe(III) oxyhydroxides precipitation can be invoked to explain Fe isotope fractionation. This work allows, for the first, time, multi-isotopic approach to trace the origin of colloids in surficial waters and it provides new constrains on chemical speciation (and, thus, bioavailability) of metals in colloids of various size. The work is executed at a Russian Federal Property Fund and CNRS support (?? 08-05-00312_a, 07-05-92212-CNRS_a).

Ilina, Svetlana M.; Viers, Jerome; Pokrovsky, Oleg S.; Poitrasson, Franck; Lapitsky, Sergey A.; Alekhin, Yuriy V.

2010-05-01

261

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.

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

2014-01-01

262

Superconductivity in barium fulleride  

NASA Astrophysics Data System (ADS)

The intercalation of fulleride with barium is reported. A pure body-centered cubic phase with a lattice constant of 11.171 A is realized near a stoichiometry of Ba6C60. This phase is also superconducting, suggesting that the mechanism of superconductivity is related to an intrinsic property of the C60 molecules, rather than the external coordination number.

Kortan, A. R.; Kopylov, N.; Glarum, S.; Gyorgy, E. M.; Ramirez, A. P.; Fleming, R. M.; Zhou, O.; Thiel, F. A.; Trevor, P. L.; Haddon, R. C.

1992-12-01

263

Semiconducting barium titanate  

Microsoft Academic Search

Barium titanate, which is well known as a basic ferroelectric material, is also of interest when doped because of the interaction between semiconductivity and ferroelectricity. The resistance of blocking layers at surfaces and grain-boundaries is governed mainly by the ferroelectric properties, so that a resistance jump of four decades is observed on heating above the Curie temperature. A survey of

W. Heywang

1971-01-01

264

Effects of silicon, copper and iron on static and dynamic properties of alloy 206 (aluminum-copper) in semi-solids produced by the SEED process  

NASA Astrophysics Data System (ADS)

The advantages of producing metal parts by rheocasting are generally recognised for common foundry alloys of Al-Si. However, other more performing alloys in terms of mechanical properties could have a great interest in specialized applications in the automotive industry, while remaining competitive in the forming. Indeed, the growing demand for more competitive products requires the development of new alloys better suited to semi-solid processes. Among others, Al-Cu alloys of the 2XX series are known for their superior mechanical strength. However, in the past, 2XX alloys were never candidates for pressure die casting. The main reason is their propensity to hot tearing. Semi-solid processes provide better conditions for molding with the rheological behavior of dough and molding temperatures lower reducing this type of defect. In the initial phase, this research has studied factors that reduce hot tearing susceptibility of castings produced by semi-solid SEED of alloy 206. Subsequently, a comparative study on the tensile properties and fatigue was performed on four variants of the alloy 206. The results of tensile strength and fatigue were compared with the specifications for applications in the automotive industry and also to other competing processes and alloys. During this study, several metallurgical aspects were analyzed. The following main points have been validated: i) the main effects of compositional variations of silicon, iron and copper alloy Al-Cu (206) on the mechanical properties, and ii) certain relationships between the mechanism of hot cracking and the solidification rate in semi-solid. Parts produced from the semi-solid paste coming from the SEED process combined with modified 206 alloys have been successfully molded and achieved superior mechanical properties than the requirements of the automotive industry. The fatigue properties of the two best modified 206 alloys were higher than those of A357 alloy castings and are close to those of the wrought alloy AA6061. At present, there is simply no known application for pressure die-cast alloy with 206 (Liquid Die-casting). This is mainly due to the high propensity to hot cracking and limitations facing the part geometry and the subsequent assembly. This study demonstrated that in addition to pieces produced by semi-solid die-casting using large variations in chemical composition, the SEED process allows obtaining spare sound (sound part) and more complex geometry. Moreover, as the semi-solid parts have less porosity, they can also be machined and welded for some applications. The conclusions of this study demonstrate significant progress in identifying the main issues related to the feasibility of die-casting good parts with high performance using the modified 206 alloy combined with SEED process. This work is therefore a baseline work in the development of new Al-Cu alloys for industries of semi-solid and, at the same time, for the expansion of aluminum for high performance applications in the industry. N.B. This thesis is part of a research project developed by the NSERC / Rio Tinto Akan Industrial Research Chair in Metallurgy of Innovative Aluminum Transformation (CIMTAL).

Lemieux, Alain

265

Rare earths and other trace elements in minerals from skarn assemblages, Hillside iron oxide-copper-gold deposit, Yorke Peninsula, South Australia  

NASA Astrophysics Data System (ADS)

The Hillside Cu-(Au) deposit, Yorke Peninsula, South Australia, is a recently-discovered ore system within the 1.6 Ga World-class Olympic iron oxide-copper-gold (IOCG) Province. The deposit is characterized by a skarn-style alteration zone. Analyses of feldspar, calcite, skarn minerals (garnet, pyroxene, clinozoisite and actinolite) and accessories (titanite, apatite and allanite), and grain-scale element mapping by laser-ablation inductively-coupled plasma mass spectrometry are used to assess the distributions of rare earth element (REE), incompatible and ore-forming elements in host rocks, prograde and retrograde skarn.

Ismail, Roniza; Ciobanu, Cristiana L.; Cook, Nigel J.; Teale, Graham S.; Giles, David; Mumm, Andreas Schmidt; Wade, Benjamin

2014-01-01

266

Ordered substitution of iron for copper in the tetragonal perovskite La{sub 6.4}Sr{sub 1.6}CuâOââ  

Microsoft Academic Search

Two series of iron-substituted cuprates with the tetragonal La{sub 6.4}Sr{sub 1.6}CuâOââ oxygen deficient perovskite structure have been isolated: La{sub 6.4}Sr{sub 1.6}Cu{sub 8-x}FeâOââ (0 ⤠x ⤠1.20) and La{sub 6.4-x}Sr{sub 1.6+x}Cu{sub 8-x}FeâOââ (0 ⤠x ⤠2). The XRD and Moessbauer studies show that they correspond to a preferential substitution of Fe(III) for copper in the octahedral sites of the

R. Genouel; C. Michel; N. Nguyen; M. Hervieu; B. Raveau

1995-01-01

267

Ordered Substitution of Iron for Copper in the Tetragonal Perovskite La 6.4Sr 1.6Cu 8O 20  

Microsoft Academic Search

Two series of iron-substituted cuprates with the tetragonal La6.4Sr1.6Cu8O20 oxygen deficient perovskite structure have been isolated: La6.4Sr1.6Cu8-xFexO20 (0 ? x ? 1.20) and La6.4-xSr1.6+x Cu8-xFexO20 (0 ? x ? 2). The XRD and Mössbauer studies show that they correspond to a preferential substitution of Fe(III) for copper in the octahedral sites of the structure. In fact the ideal structure can

R. Genouel; C. Michel; N. Nguyen; M. Hervieu; B. Raveau

1995-01-01

268

Electrochemical synthesis and crystal structure of iron(II), cobalt(II), nickel(II) and copper(II) complexes of dianionic tetradentate N4 Schiff base ligand  

Microsoft Academic Search

The electrochemical oxidation of anodic metal (iron, cobalt, nickel and copper) in an acetonitrile solution of the potentially chelating Schiff base N,N(dithiodiethylenebis-(aminylydenemethylydene)-bis(1,2-phenylene)ditosylamide (H2L) afforded stable complexes of empirical formula [ML]. The compounds obtained have been characterized by microanalysis, IR spectroscopy and ES-MS mass spectrometry. The crystal and molecular structures of [FeL]·CH3CN (1) [CoL]·CH3CN (2), [NiL]·CH3CN (3) and [CuL]·CH3CN (4) have

Laura Rodríguez; Elena Labisbal; Antonio Sousa-Pedrares; José Arturo García-Vázquez; Jaime Romero; Antonio Sousa

2010-01-01

269

Chemical nature of DNA-protein cross-links produced in mammalian chromatin by hydrogen peroxide in the presence of iron or copper ions  

Microsoft Academic Search

The authors report on the elucidation of DNA-protein cross-links formed in isolated mammalian chromatin upon treatment with HâOâ in the presence of iron or copper ions. Analysis of chromatin samples by gas chromatography\\/mass spectrometry after hydrolysis and derivatization showed the presence of 3-((1,3-dihydro-2,4-dioxopyrimidin-5-yl)methyl)-L-tyrosine (thymine-tyrosine cross-link) on the basis of the gas chromatographic and mass spectrometric characteristics of the trimethylsilylated authentic

Zeena Nackerdien; Govind Rao; Marco A. Cacciuttolo; Ewa Gajewski; Miral Dizdaroglu

1991-01-01

270

Release of aluminum, arsenic, cadmium, chromium, copper, iron, lead, and zinc in a coal leachate, and their removal from solution undergoing neutralization  

SciTech Connect

Whole coal contains significant amounts of iron pyrite which is oxidized ultimately to ferric acid sulfate. As a result, trace elements are released from the coal and other minerals in potentially hazardous concentrations. The purpose of this research was to: (1) study the release and mobility of selected trace elements during the weathering of coal; (2) seek to understand factors controlling solubility of trace elements in a synthetic, acidic leachate undergoing gradual neutralization; and (3) develop a chemical thermodynamic computer model to predict the effects of dilution and neutralization of leachate on trace element mobility and speciation. Samples collected periodically from a slurry of whole ground coal in water were filtered and analyzed for dissolved sulfate (by ion chromatography), iron (by flame atomic absorption spectrophotometry), and Al, Zn, Cd, Cu, Cr, Pb, As, and Se (by graphite furnace AAS). Iron, copper, and probably arsenic tracked the production of sulfate, while aluminum, zinc, chromium, and cadmium concentrations were stable or rose slightly. A synthetic leachate of ferric sulfate and sulfuric acid was doped with trace levels of Al, Zn, Cu, Cd, Cr, Pb, As, and Se. Slow injection of sodium bicarbonate solution neutralized the stirred system, though hydrolysis of iron buffered the pH and 2.5.

Tatum, T.L.

1992-01-01

271

Direct functionalization processes: a journey from palladium to copper to iron to nickel to metal-free coupling reactions.  

PubMed

The possibility of finding novel disconnections for the efficient synthesis of organic molecules has driven the interest in developing technologies to directly functionalize C-H bonds. The ubiquity of these bonds makes such transformations attractive, while also posing several challenges. The first, and perhaps most important, is the selective functionalization of one C-H bond over another. Another key problem is inducing reactivity at sites that have been historically unreactive and difficult to access without prior inefficient prefunctionalization. Although remarkable advances have been made over the past decade toward solving these and other problems, several difficult tasks remain as researchers attempt to bring C-H functionalization reactions into common use. The functionalization of sp(3) centers continues to be challenging relative to their sp and sp(2) counterparts. Directing groups are often needed to increase the effective concentration of the catalyst at the targeted reaction site, forming thermodynamically stable coordination complexes. As such, the development of removable or convertible directing groups is desirable. Finally, the replacement of expensive rare earth reagents with less expensive and more sustainable catalysts or abandoning the use of catalysts entirely is essential for future practicality. This Account describes our efforts toward solving some of these quandaries. We began our work in this area with the direct arylation of N-iminopyridinium ylides as a universal means to derivatize the germane six-membered heterocycle. We found that the Lewis basic benzoyl group of the pyridinium ylide could direct a palladium catalyst toward insertion at the 2-position of the pyridinium ring, forming a thermodynamically stable six-membered metallocycle. Subsequently we discovered the arylation of the benzylic site of 2-picolonium ylides. The same N-benzoyl group could direct a number of inexpensive copper salts to the 2-position of the pyridinium ylide, which led to the first description of a direct copper-catalyzed alkenylation onto an electron-deficient arene. This particular directing group offers two advantages: (1) it can be easily appended and removed to reveal the desired pyridine target, and (2) it can be incorporated in a cascade process in the preparation of pharmacologically relevant 2-pyrazolo[1,5-a]pyridines. This work has solved some of the challenges in the direct arylation of nonheterocyclic arenes, including reversing the reactivity often observed with such transformations. Readily convertible directing groups were applied to facilitate the transformation. We also demonstrated that iron can promote intermolecular arylations effectively and that the omission of any metal still permits intramolecular arylation reactions. Lastly, we recently discovered a nickel-catalyzed intramolecular arylation of sp(3) C-H bonds. Our mechanistic investigations of these processes have elucidated radical pathways, opening new avenues in future direct C-H functionalization reactions. PMID:23098328

Mousseau, James J; Charette, André B

2013-02-19

272

Anti-oxidant and pro-oxidant reactivities of copper(II), manganese(II) and iron(III) 3,5-di- i -propylsalicylate chelates during peroxidation of alkylbenzenes  

Microsoft Academic Search

Bioactive copper(II), iron(III), and manganese(II) 3,5-di-i-propylsalicylate (3,5-DIPS) chelates were investigated in order to determine their ability to inhibit the free radical initiated chain reactions leading to the peroxidation of isopropylbenzene (i-PrPh) and ethylbenzene (EtPh). Quantitative kinetic studies of these chelates established the following order of anti-oxidant reactivities: manganese(II)-(3,5-DIPS)2>iron(III)(3,5-DIPS)3>copper(II)2(3,5-DIPS)4> > 3,5-DIPS acid. The mechanism of anti-oxidant reactivity of these three chelates

Levon A. Tavadyan; Gegham Z. Sedrakyan; Seyran H. Minasyan; Frederick T. Greenaway; John R. J. Sorenson

2004-01-01

273

75 FR 33824 - Barium Chloride From China  

Federal Register 2010, 2011, 2012, 2013

...No. 731-TA-149 (Third Review)] Barium Chloride From China Determination On the...revocation of the antidumping duty order on barium chloride from China would be likely to...Publication 4157 (June 2010), entitled Barium Chloride from China: Investigation...

2010-06-15

274

75 FR 19657 - Barium Chloride From China  

Federal Register 2010, 2011, 2012, 2013

...No. 731-TA-149 (Third Review)] Barium Chloride From China AGENCY: United States...concerning the antidumping duty order on barium chloride from China...revocation of the antidumping duty order on barium chloride from China would be likely...

2010-04-15

275

Properties of Semiconductive Barium Titanates  

Microsoft Academic Search

The resistivity of barium titanate which is usually of the order of 109˜1012 ohm-cm, may be remarkably reduced with suitable control in valency. The valency-controlled barium titanate, whose resistivity is of the order of 10˜104 ohm-cm at room temperature, shows anomalous positive character in the temperature dependency of the resistivity. For example, the resistivity of barium titanate containing 0.1 mol.

Osamu Saburi

1959-01-01

276

Optimized photorefractive barium titanate  

Microsoft Academic Search

The goal of this research program was to investigate new and modified crystal-growth techniques that would lead to high-optical-quality BaTiO3 with increased photorefractive speed and sensitivity. The research program consisted of four parts: (1) feed material purification; (2) crystal growth by the top-seeded-solution technique as well as by a barium borate flux technique; (3) new furnace design studies; and (4)

Cardinal Warde; Hans P. Jenssen

1992-01-01

277

Concentrations of copper, iron, and zinc in the major organs of the wistar albino and wild black rats: a comparative study.  

PubMed

The concentrations of copper, iron, and zinc in the major organs of Wistar albino (Rattus norvegicus) and wild black rats (Rattus rattus) were measured by means of atomic absorption spectroscopy. The copper levels in the kidneys and liver of the Wistar albino rats (WARs) were significantly higher (p<0.05) than in the wild black rats (WBRs). There were no significant differences in the concentrations of zinc in the liver, lungs, kidneys, and brain between the two study groups, but zinc was significantly higher in the spleen (p<0.05) and lower in the heart (p<0.05) of WAR, compared to WBRs. Iron was significantly higher (p<0.05) in the heart and spleen of WBRs, compared to WARs. There were no extreme differences in the organ concentrations of trace elements between the two species, but, cumulatively, the WARs tend to have higher metallic concentrations in their system than the WBRs. The potential of these differences on the experimental results should not be overlooked and will serve as basis to further consider the complex interrelationships of these animals in their microenvironments and macroenvironments. PMID:15131322

Olusola, A O; Obodozie, O O; Nssien, M; Adaramoye, A; Adesanoye, O; Odama, L E; Emerole, G O

2004-06-01

278

Syntheses and structural characterization of iron(II) and copper(II) coordination compounds with the neutral flexible bidentate N-donor ligands  

NASA Astrophysics Data System (ADS)

Two new coordination compounds [Fe(bib)2(N3)2]n(1) and [Cu2(bpp)2(N3)4] (2) with azide and flexible ligands 1,4-bis(imidazolyl)butane (bib) and 1,3-bis(3,5-dimethylpyrazolyl)propane (bpp) were prepared and structurally characterized. In the 2D network structure of 1, the iron(II) ion lies on an inversion center and exhibits an FeN6 octahedral arrangement while in the dinuclear structure of 2, the copper(II) ion adopts an FeN5 distorted square pyramid geometry. In the complex 1, each ?2-bib acts as bridging ligand connecting two adjacent iron(II) ions while in the complex 2, the bpp ligand is coordinated to copper(II) ion in a cyclic-bidentate fashion forming an eight-membered metallocyclic ring. Coordination compounds 1 and 2 have been characterized by infrared spectroscopy, elemental analyses and single-crystal X-ray diffraction. Thermal analysis of polymer 1 was also studied.

Beheshti, Azizolla; Lalegani, Arash; Bruno, Giuseppe; Rudbari, Hadi Amiri

2014-08-01

279

KEY COMPARISON: Final report on key comparison CCQM-K42: Determination of chromium, copper, iron, manganese and zinc in aluminium alloy  

NASA Astrophysics Data System (ADS)

The CCQM key comparison K42 was organized by the inorganic analysis working group of CCQM to test the abilities of metrological institutes to measure the mass fractions of the components of an aluminium alloy. Chosen elements were chromium (Cr), copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn). The BAM Federal Institute for Materials Research and Testing (BAM Bundesanstalt für Materialforschung und -prüfung) in Berlin, Germany acted as the pilot laboratory. CCQM-K42 demonstrates the abilities of metrological institutes to measure the mass fractions of minor and trace components (mass content about 0.05% to 0.2%) of an aluminium alloy for chromium (Cr), copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn). The analytical methods used were neutron activation analysis (NAA), x-ray fluorescence spectrometry (XRF) using the reconstitution technique, ICP-OES and ICP-MS. The scope of the key comparison extends to non-ferrous alloys comprising the same or similar constituents when analysed using the technique(s) applied by a participant in obtaining the results submitted for CCQM-K42. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Noack, Siegfried; Matschat, Ralf

2008-01-01

280

Distribution of copper, iron, and zinc in biological samples (scalp hair, serum, blood, and urine) of Pakistani viral hepatitis (A-E) patients and controls.  

PubMed

The aim of the present study was to compare the level of copper (Cu), iron (Fe) and zinc (Zn) in biological samples (serum, blood, urine, and scalp hair) of patients suffering from different viral hepatitis (A, B, C, D, and E; n = 521) of both gender age ranged 31-45 years. For comparative study, 255 age-matched control subjects, of both genders residing in the same city were selected as referents. The elements in the biological samples were analyzed by flame atomic absorption spectrophotometry, prior to microwave-assisted acid digestion. The validity and accuracy of the methodology was checked by using certified reference materials (CRMs) and with those values obtained by conventional wet acid digestion method on same CRMs. The results of this study showed that the mean values of Cu and Fe were higher in blood, sera, and scalp hair samples of hepatitis patients, while Zn level was found to be lower than age-matched control subjects. The urinary levels of these elements were found to be higher in the hepatitis patients than in the age-matched healthy controls (p < 0.05). These results are consistent with literature-reported data, confirming that the deficiency of zinc and hepatic iron and copper overload can directly cause lipid peroxidation and eventually hepatic damage. PMID:20872092

Kolachi, Nida Fatima; Kazi, Tasneem Gul; Afridi, Hassan Imran; Kazi, Naveed; Kandhro, Ghulam Abbas; Shah, Abdul Qadir; Baig, Jameel Ahmed; Wadhwa, Sham Kumar; Khan, Sumaira; Shah, Faheem; Jamali, Mohammad Khan; Arain, Mohammad Balal

2011-10-01

281

In vitro bioaccessibility of copper, iron, zinc and antioxidant compounds of whole cashew apple juice and cashew apple fibre (Anacardium occidentale L.) following simulated gastro-intestinal digestion.  

PubMed

Considering the lack of research studies about nutrients' bioaccessibility in cashew apple, in this study the whole cashew apple juice and the cashew apple fibre were submitted to simulated in vitro gastrointestinal digestion. The samples were analysed before and after digestion and had their copper, iron, zinc, ascorbic acid, total extractable phenols and total antioxidant activity assessed. As a result, for the whole cashew apple juice, the content of copper and iron minerals bioaccessible fraction were 15% and 11.5% and for zinc this level was 3.7%. Regarding the cashew apple fibre, the bioaccessible fraction for these minerals was lower than 5%. The ascorbic acid, total extractable polyphenols and total antioxidant activity bioaccessible fraction for whole cashew apple juice showed bioaccessibility percentages of 26.2%, 39% and 27%, respectively, while for the cashew apple fibre, low bioaccessibles levels were found. The bioacessible percentage of zinc, ascorbic acid and total extractable polyphenols were higher in cashew apple juice than cashew apple fibre. PMID:24837932

de Lima, Ana Cristina Silva; Soares, Denise Josino; da Silva, Larissa Morais Ribeiro; de Figueiredo, Raimundo Wilane; de Sousa, Paulo Henrique Machado; de Abreu Menezes, Eveline

2014-10-15

282

Microstructural Evolution and Mechanical Properties of Fusion Welds and Simulated Heat-Affected Zones in an Iron-Copper Based Multi-Component Steel  

NASA Astrophysics Data System (ADS)

NUCu-140 is a copper-precipitation strengthened steel that exhibits excellent mechanical properties with a relatively simple chemical composition and processing schedule. As a result, NUCu-140 is a candidate material for use in many naval and structural applications. Before NUCu-140 can be implemented as a replacement for currently utilized materials, a comprehensive welding strategy must be developed under a wide range of welding conditions. This research represents an initial step toward understanding the microstructural and mechanical property evolution that occurs during fusion welding of NUCu-140. The following dissertation is presented as a series of four chapters. Chapter one is a review of the relevant literature on the iron-copper system including the precipitation of copper in steel, the development of the NUCu family of alloys, and the formation of acicular ferrite in steel weldments. Chapter two is a detailed study of the precipitate, microstructural, and mechanical property evolution of NUCu-140 fusion welds. Microhardness testing, tensile testing, local-electrode atom probe (LEAP) tomography, MatCalc kinetic simulations, and Russell-Brown strengthening results for gas-tungsten and gas-metal arc welds are presented. Chapter three is a thorough study of the microstructural and mechanical property evolution that occurs in the four critical regions of the HAZ. Simulated HAZ specimens were produced and evaluated using microhardness, tensile testing, and charpy impact testing. MatCalc simulations and R-B strengthening calculations were also performed in an effort to model the experimentally observed mechanical property trends. Chapter 4 is a brief investigation into the capabilities of MatCalc and the R-B model to determine if the two techniques could be used as predictive tools for a series of binary iron-copper alloys without the aid of experimentally measured precipitate data. The mechanical property results show that local softening occurs in the heat-affected zone (HAZ) as a result of either full or partial dissolution of the copper-rich precipitates responsible for strengthening. Re-precipitation of the copper-rich precipitates was observed during the cooling portion of the weld thermal cycle but the resultant precipitate phase fractions were too low to fully recover the lost strength. The coarse-grained HAZ and fusion zone exhibited an acicular type microstructure which led to improved tensile properties when compared to the other regions of the HAZ. MatCalc simulations displayed excellent agreement with the precipitate parameters measured experimentally using the LEAP. The R-B model was shown to provide reasonable agreement under select conditions, but in general was determined to be overly sensitive to small variations in precipitate parameters. As a result in should be considered a qualitative tool only for precipitate radii less than ˜2 nm. Finally, it was determined that the current generation of MatCalc software was unable to accurately capture the precipitate evolution of various binary iron-copper alloys when experimental data sets were not available for calibration of the model parameters.

Farren, Jeffrey David

283

The barium iron ruthenium oxide system  

NASA Technical Reports Server (NTRS)

In the system BaFe(1-x)Ru(x)O(3-y), three phases, separated by immiscibility gaps, are present: an Fe-rich phase (x = 0 to 0.75) with hexagonal BaTiO3 structure (6H; sequence (hcc)2), a Ru-rich phase (x = 0.9) of hexagonal 4H-type (sequence (hc)2), and the pure Ru compounds BaRuO3 with rhombohedral 9R structure (sequence (hhc)3). By vibrational spectroscopic investigations in the 6H phase a transition from n-type semiconduction (Fe-rich compounds with complete O lattice) can be detected. The 4H and 9R stacking polytypes are good, metal-like conductors. The lattice parameters are given.

Kemmler-Sack, S.; Ehmann, A.

1986-01-01

284

Iron, manganese and copper emitted by cargo and passenger trains in Zürich (Switzerland): Size-segregated mass concentrations in ambient air  

NASA Astrophysics Data System (ADS)

Particle emissions caused by railway traffic have hardly been investigated in the past, due to their obviously minor influence on air quality compared to automotive traffic. In this study, emissions related to particle abrasion from wheels and tracks were investigated next to a busy railway line in Zürich (Switzerland), where trains run nearly exclusively with electrical locomotives. Hourly size-segregated aerosol samples (0.1-1, 1-2.5 and 2.5-10 ?m) were collected with a rotating drum impactor (RDI) and subsequently analyzed by synchrotron radiation X-ray fluorescence spectrometry (SR-XRF). In this way, hourly elemental mass concentrations were obtained for chromium, manganese, iron and copper, which are the elements most relevant for railway abrasion. Additionally, daily aerosol filters were collected at the same site as well as at a background site for subsequent analysis by gravimetry and wavelength dispersive XRF (WD-XRF). Railway related ambient air concentrations of iron and manganese were calculated for the coarse (2.5-10 ?m) and fine (<2.5 ?m) particle fraction by means of a Mn/Fe ratio investigation. The comparison to train type and frequency data showed that 75% and 60% of the iron and manganese mass concentrations related to cargo and passenger trains, respectively, were found in the coarse mode. The railway related iron mass concentration normalized by the train frequency ranges between 10 and 100 ng m -3 h iron in 10 m distance to the tracks, depending on train type. It is estimated that the personal exposure next to a busy railway line above ground is more than a magnitude lower than inside a subway station.

Bukowiecki, Nicolas; Gehrig, Robert; Hill, Matthias; Lienemann, Peter; Zwicky, Christoph N.; Buchmann, Brigitte; Weingartner, Ernest; Baltensperger, Urs

285

Barium peritonitis in small animals.  

PubMed

Barium peritonitis is extremely rare, but is difficult to treat and may be life-threatening. Barium suspension leakage from the gastrointestinal tract into the abdominal cavity has a time-dependent and synergistically deleterious effect in patients who have generalized bacterial peritonitis. The severity of barium peritonitis is dependent on the quantity of barium in the abdominal cavity. Barium sulfate leakage results in hypovolemia and hypoproteinemia by worsening the exudation of extracellular fluid and albumin. Abdominal fluid analysis is a useful and efficient method to diagnose barium peritonitis. Serial radiographs may not be a reliable or timely diagnostic technique. Initial aggressive fluid resuscitation and empirical broad-spectrum antibiotic treatment should be instituted promptly, followed quickly by celiotomy. During exploratory surgical intervention, copious irrigation and direct wiping with gauze are employed to remove as much barium as possible. Omentectomy should be considered when needed to expedite barium removal. Despite aggressive medical and surgical treatments, postoperative prognosis is guarded to poor due to complications, such as acute vascular shock, sepsis, diffuse peritonitis, hypoproteninemia, electrolyte imbalance, cardiac arrest, small bowel obstruction related to progression of granulomas and adhesions in the abdominal cavity. Therefore, intensive postoperative monitoring and prompt intervention are necessary to maximize chances for a positive outcome. For those that do survive, small bowel obstruction is a potential consequence due to progression of abdominal adhesions. PMID:24430662

Ko, Jae Jin; Mann, F A Tony

2014-06-01

286

Barium Peritonitis in Small Animals  

PubMed Central

ABSTRACT Barium peritonitis is extremely rare, but is difficult to treat and may be life-threatening. Barium suspension leakage from the gastrointestinal tract into the abdominal cavity has a time-dependent and synergistically deleterious effect in patients who have generalized bacterial peritonitis. The severity of barium peritonitis is dependent on the quantity of barium in the abdominal cavity. Barium sulfate leakage results in hypovolemia and hypoproteinemia by worsening the exudation of extracellular fluid and albumin. Abdominal fluid analysis is a useful and efficient method to diagnose barium peritonitis. Serial radiographs may not be a reliable or timely diagnostic technique. Initial aggressive fluid resuscitation and empirical broad-spectrum antibiotic treatment should be instituted promptly, followed quickly by celiotomy. During exploratory surgical intervention, copious irrigation and direct wiping with gauze are employed to remove as much barium as possible. Omentectomy should be considered when needed to expedite barium removal. Despite aggressive medical and surgical treatments, postoperative prognosis is guarded to poor due to complications, such as acute vascular shock, sepsis, diffuse peritonitis, hypoproteninemia, electrolyte imbalance, cardiac arrest, small bowel obstruction related to progression of granulomas and adhesions in the abdominal cavity. Therefore, intensive postoperative monitoring and prompt intervention are necessary to maximize chances for a positive outcome. For those that do survive, small bowel obstruction is a potential consequence due to progression of abdominal adhesions.

KO, Jae Jin; MANN, F. A. (Tony)

2014-01-01

287

Metal ions as potential regulatory factors in the biosynthesis of red hair pigments: a new benzothiazole intermediate in the iron or copper assisted oxidation of 5- S-cysteinyldopa  

Microsoft Academic Search

In the presence of iron or copper ions, the course of the oxidation in air of 5-S-cysteinyldopa (1), the main biosynthetic precursor of pheomelanins and trichochromes, was markedly changed affording two main products. One of these was identified as the oxobenzothiazine 8, previously obtained under nonphysiologically relevant conditions, while the other was characterized as the novel hydroxybenzothiazole 9. Besides 8

Paola Di Donato; Alessandra Napolitano; Giuseppe Prota

2002-01-01

288

Entrainment behavior of copper and copper matte in copper smelting operations  

Microsoft Academic Search

In copper smelting, the loss of copper to the slag due to entrainment is largely influenced by the flotation of copper metal\\u000a and\\/or matte in the slag phase. To evaluate this behavior, the surface tension of copper as a function of temperature and\\u000a oxygen pressure and the interfacial tension of the copper-iron matte-slag system as a function of matte grade

S. W. Ip; J. M. Toguri

1992-01-01

289

Barium iron arsenide, barium cobalt arsenide, barium nickel arsenide single crystals and superconductivity upon cobalt doping  

SciTech Connect

The crystal structure and physical properties of BaFe{sub 2}As{sub 2}, BaCo{sub 2}As{sub 2}, and BaNi{sub 2}As{sub 2} single crystals are surveyed. BaFe{sub 2}As{sub 2} gives a magnetic and structural transition at T{sub N} = 132(1) K, BaCo{sub 2}As{sub 2} is a paramagnetic metal, while BaNi{sub 2}As{sub 2} has a structural phase transition at T{sub 0} = 131 K, followed by superconductivity below {Tc} = 0.69 K. The bulk superconductivity in Co-doped BaFe{sub 2}As{sub 2} below {Tc} = 22 K is demonstrated by resistivity, magnetic susceptibility, and specific heat data. In contrast to the cuprates, the Fe-based system appears to tolerate considerable disorder in the transition metal layers. First principles calculations for BaFe{sub 1.84}Co{sub 0.16}As{sub 2} inter-band scattering due to Co is weak.

Ronning, Filip [Los Alamos National Laboratory; Sefat, A S [ORNL; Mcguire, M M [ORNL; Sales, B [ORNL; Jin, R [ORNL; Mandrus, D [ORNL

2009-01-01

290

Barium uranyl diphosphonates  

NASA Astrophysics Data System (ADS)

Three Ba2+/UO22+ methylenediphosphonates have been prepared from mild hydrothermal treatment of uranium trioxide, methylendiphosphonic acid (C1P2) with barium hydroxide octahydrate, barium iodate monohydrate, and small aliquots of HF at 200 °C. These compounds, Ba[UO2[CH2(PO3)2]·1.4H2O (Ba-1), Ba3[(UO2)4(CH2(PO3)2)2F6]·6H2O (Ba-2), and Ba2[(UO2)2(CH2(PO3)2)F4]·5.75H2O (Ba-3) all adopt layered structures based upon linear uranyl groups and disphosphonate molecules. Ba-2 and Ba-3 are similar in that they both have UO5F2 pentagonal bipyramids that are bridged and chelated by the diphosphonate moiety into a two-dimensional zigzag anionic sheet (Ba-2) and a one-dimensional ribbon anionic chain (Ba-3). Ba-1, has a single crystallographically unique uranium metal center where the C1P2 ligand solely bridges to form [UO2[CH2(PO3)2]2- sheets. The interlayer space of the structures is occupied by Ba2+, which, along with the fluoride ion, mediates the structure formed and maintains overall charge balance.

Nelson, Anna-Gay D.; Alekseev, Evgeny V.; Ewing, Rodney C.; Albrecht-Schmitt, Thomas E.

2012-08-01

291

Effect of lead in water on the absorption of copper, iron, manganese and zinc by sheep (Ovis aries) infected with sheep tapeworm (Moniezia expansa).  

PubMed

The sheep tapeworm (Moniezia expansa) and its host Ovis aries were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES) for their copper, iron, manganese, zinc and lead levels. Element concentrations in cestode parasites were compared to those in various organs (liver, kidney, and muscle) of sheep. Tapeworms in the small intestine of sheep that were administered 2g of Pb(CH(3)COO)(2) per os daily (7 days) had significantly higher lead concentrations than sheep tissues. Cu levels significantly increased after Pb administration in sheep muscle and sheep tapeworms. Contrarily, Zn content significantly decreased in sheep muscle, but significantly increased in sheep tapeworms. However, Mn content significantly decreased after Pb administration in sheep tapeworms. Furthermore, Fe content significantly decreased after Pb administration in sheep liver and kidneys. PMID:22425750

Jankovská, I; Száková, J; Lukešová, D; Langrová, I; Válek, P; Vadlejch, J; ?adková, Z; Petrtýl, M

2012-05-01

292

Table of interplanar spacings for crystal-structure determinations by X-ray diffraction with molybdenum, copper, cobalt, iron, and chromium radiations  

NASA Technical Reports Server (NTRS)

For a simple diffraction pattern, the time required to calculate interplanar distances from measurements of the pattern is not excessive. If more than a few lines are present, however, or if several patterns are to be studied, it is very advantageous to have available a table giving interplanar spacings directly in terms of the linear measurements made on the film of the lines appearing on the diffraction pattern. The preparation of the table given here was undertaken when the expansion of research activities involving X-ray diffraction techniques indicated that such a table would greatly decrease the time required to analyze diffraction patterns. The table was prepared for use with K alpha(sub 1) radiation from the following target materials: molybdenum, copper, cobalt, iron, and chromium.

Kittel, J Howard

1945-01-01

293

Development of a selective and sensitive flotation method for determination of trace amounts of cobalt, nickel, copper and iron in environmental samples.  

PubMed

A simple, selective and rapid flotation method for the separation-preconcentration of trace amounts of cobalt, nickel, iron and copper ions using phenyl 2-pyridyl ketone oxime (PPKO) has been developed prior to their flame atomic absorption spectrometric determinations. The influence of pH, amount of PPKO as collector, type and amount of eluting agent, type and amount of surfactant as floating agent and ionic strength was evaluated on the recoveries of analytes. The influences of the concomitant ions on the recoveries of the analyte ions were also examined. The enrichment factor was 93. The detection limits based on 3 sigma for Cu, Ni, Co and Fe were 0.7, 0.7, 0.8, and 0.7 ng mL(-1), respectively. The method has been successfully applied for determination of trace amounts of ions in various real samples. PMID:17602834

Karimi, H; Ghaedi, M; Shokrollahi, A; Rajabi, H R; Soylak, M; Karami, B

2008-02-28

294

Ordered Substitution of Iron for Copper in the Tetragonal Perovskite La 6.4Sr 1.6Cu 8O 20  

NASA Astrophysics Data System (ADS)

Two series of iron-substituted cuprates with the tetragonal La 6.4Sr 1.6Cu 8O 20 oxygen deficient perovskite structure have been isolated: La 6.4Sr 1.6Cu 8- xFe xO 20 (0 ? x ? 1.20) and La 6.4- xSr 1.6+ x Cu 8- xFe xO 20 (0 ? x ? 2). The XRD and Mössbauer studies show that they correspond to a preferential substitution of Fe(III) for copper in the octahedral sites of the structure. In fact the ideal structure can be described as 90°-oriented "123" copper ribbons interconnected with [FeO 3] ? rows of FeO 6 octahedra. The transport properties of these phases show a transition from a metallic to a semiconducting state. The difference in behavior between the La 6.4Sr 1.6Cu 8- xFe xO 20 series and the La 6.4- xSr 1.6+ xCU 8- xFe xO 20 series is interpreted on the basis of hole carrier density introduced by Cu(III) and of the trapping of carriers by Fe(III) species. The possibility of anisotropic transport properties with a metallic conductivity along c is discussed.

Genouel, R.; Michel, C.; Nguyen, N.; Hervieu, M.; Raveau, B.

1995-03-01

295

Determination of barium in sulphide ores, concentrates and other geological samples by flame atomic-absorption spectrometry.  

PubMed

A rapid, precise and selective analytical method has been developed for estimation of barium in geological samples by flame atomic-absorption spectrometry. The method consists of precipitation of barium sulphate with ammonium sulphate, followed by dissolution of the sulphates in EDTA at pH 10. The barium in this solution is measured by AAS with a nitrous oxide-acetylene flame. Appreciable amounts of lead, calcium and strontium can be tolerated in the method, which has been applied for estimation of barium in sulphide ores and concentrates of lead, zinc and copper, and is feasible for estimation of barium from 20.0 ppm to the per cent level in such geological samples. PMID:18963404

Sharma, K D

1983-07-01

296

Formation of nickel and copper ferrites in ceramics: a potential reaction in the reuse of iron-rich sludge incineration ash.  

PubMed

This study investigates potential solid-state reactions for the stabilization of hazardous metals when reusing the incineration ash from chemically enhanced primary treatment (CEPT) sludge to fabricate ceramic products. Nickel and copper were used as examples of hazardous metals, and the iron content in the reaction system was found to play a major role in incorporating these hazardous metals into their ferrite phases (NiFe2O4 and CuFe2O4). The results from three-hour sintering experiments on NiO + Fe2O3 and CuO + Fe2O3 systems clearly demonstrate the potential for initiating metal incorporation mechanisms using an iron-containing precursor at attainable ceramic sintering temperatures (above 750 degrees C). Both ferrite phases were examined using a prolonged leaching experiment modified from the widely used toxicity characteristic leaching procedure (TCLP) to evaluate their long-term metal leachability. The leaching results indicate that both the NiFe2O4 and the CuFe2O4 products were significantly superior to their oxide forms in immobilizing hazardous metals. PMID:23437648

Shih, Kaimin

2012-12-01

297

On-line copper and iron removal and selenium(VI) pre-reduction for the determination of total selenium by flow-injection hydride generation-inductively coupled plasma optical emission spectrometry  

NASA Astrophysics Data System (ADS)

Selenium was determined in samples with high copper and iron contents by hydride generation-inductively coupled plasma optical emission spectrometry (HG-ICP-OES) after flow-injection (FI) on-line copper and iron removal and selenium(VI) reduction. A Dowex 1X-8 anion-exchange microcolumn was used for the separation of selenium from copper and iron as their chloro-complexes. Se(VI) was then reduced on-line by heating a PTFE coiled reactor (150 cm long, 0.7 mm i.d.) in a 100°C water bath. After reduction of Se(VI), a 900-?l sample was injected into the carrier stream containing hydrochloric acid and sodium tetrahydroborate to generate the hydride. A limit of detection of 0.4 ?g l -1 (RSD 2.3% for 20 ?g l -1 selenium) was obtained. The application of the method to Geochemical Standard Reference Samples and copper metal reference materials (MBH) demonstrated that results were in good statistical accordance with certified values.

Stripeikis, Jorge; Tudino, Mabel; Troccoli, Osvaldo; Wuilloud, Rodolfo; Olsina, Roberto; Martinez, Luis

2001-01-01

298

Discovery of the barium isotopes  

SciTech Connect

Thirty-eight barium isotopes have been observed so far and the discovery of these isotopes is discussed here. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

Shore, A.; Fritsch, A.; Ginepro, J.Q.; Heim, M.; Schuh, A. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Thoennessen, M., E-mail: thoennessen@nscl.msu.ed [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

2010-11-15

299

A tunable combline bandpass filter using barium strontium titanate interdigital varactors on an alumina substrate  

Microsoft Academic Search

Barium strontium titanate (BST) has a field-dependent permittivity that enables it to be used as a dielectric in a voltage-tunable capacitor or varactor. A tunable combline bandpass filter was designed and characterized using BST varactors fabricated on a polycrystalline alumina substrate with copper metallization and is 14 mm × 14 mm in size. The center frequency of the filter varies

Jayesh Nath; W. Fathelbab; P. D. Franzon; A. I. Kingon; D. Ghosh; Jon-Paul Maria; M. B. Steer

2005-01-01

300

Built-Up Films of Barium Stearate and Their Optical Properties  

Microsoft Academic Search

The technique of depositing successive single layers of molecules of various stearates on a solid surface is described. Films containing 3001 layers have been built of barium-copper stearate. A photograph shows films built in a series of steps having intervals of 2 molecular layers. The contrast of the steps is plainly visible when the slide is illuminated by polarized light

Katharine B. Blodgett; Irving Langmuir

1937-01-01

301

The vacuolar H + ATPase of Saccharomyces cerevisiae is required for efficient copper detoxification, mitochondrial function, and iron metabolism  

Microsoft Academic Search

Mutations in the GEF2 gene of the yeast Saccharomyces cerevisiae have pleiotropic effects. The gef2 mutants display a petite phenotype. These cells grow slowly on several different carbon sources utilized exclusively or primarily by respiration. This phenotype is suppressed by adding large amounts of iron to the growth medium. A defect in mitochondrial function may be the cause of the

David J. Eide; Jamie T. Bridgham; Zhong Zhao; James R. Mattoon

1993-01-01

302

Copper, iron, zinc, and selenium dietary intake and status of Nepalese lactating women and their breast-fed infants13  

Microsoft Academic Search

The dietary intake ofcopper, iron, zinc, and selenium of26 Nepalese lactat- ing mothers was estimated from chemical analysis of24-h food and beverage composites. Fast- ing blood and milk samples were obtained from the mothers and blood samples were obtained from the infants. The Nepalese mothers consumed significantly more Cu, significantly less Fe and Se, and similar amounts of Zn as

Phylis B Moser; Robert D Reynolds; Suniti Acharya; M Pat Howard; Mark B Andon; Susan A Lewis

303

Thermoelectric power of homovalent copper alloys. (Oxidation)  

Microsoft Academic Search

An oxidation technique has been used to remove traces of iron from copper-gold and copper-silver alloys and the low temperature thermoelectric power of these homovalent copper alloys has been used to study the success of the oxidation procedure. The electron diffusion and phonon drag contributions to thermoelectric power characteristic to the scattering from silver and gold impurities in copper are

A. M. Guenault

1974-01-01

304

Evidence for a copper-dependent iron transport system in the marine, magnetotactic bacterium strain MV1  

Microsoft Academic Search

Cells of the magnetotactic marine vibrio, strain MV-1, produce magnetite-containing magnetosomes when grown anaerobically or microaerobically. Stable, spontaneous, non-magnetotactic mutants were regularly observed when cells of MV-1 were cultured on solid media incubated under anaerobic or microaerobic conditions. Randomly amplified polymorphic DNA analysis showed that these mutants are not all genetically identical. Cellular iron content of one non-magnetotactic mutant strain,

Bradley L. Dubbels; Alan A. DiSpirito; John D. Morton; Jeremy D. Semrau; J. N. E. Neto; Dennis A. Bazylinski

2004-01-01

305

Synthesis and microwave absorption properties of yolk-shell microspheres with magnetic iron oxide cores and hierarchical copper silicate shells.  

PubMed

Yolk-shell microspheres with magnetic Fe3O4 cores and hierarchical copper silicate shells have been successfully synthesized by combining the versatile sol-gel process and hydrothermal reaction. Various yolk-shell microspheres with different core size and shell thickness can be readily synthesized by varying the experimental conditions. Compared to pure Fe3O4, the as-synthesized yolk-shell microspheres exhibit significantly enhanced microwave absorption properties in terms of both the maximum reflection loss value and the absorption bandwidth. The maximum reflection loss value of these yolk-shell microspheres can reach -23.5 dB at 7 GHz with a thickness of 2 mm, and the absorption bandwidths with reflection loss lower than -10 dB are up to 10.4 GHz. Owing to the large specific surface area, high porosity, and synergistic effect of both the magnetic Fe3O4 cores and hierarchical copper silicate shells, these unique yolk-shell microspheres may have the potential as high-efficient absorbers for microwave absorption applications. PMID:23474005

Liu, Jiwei; Cheng, Jin; Che, Renchao; Xu, Junjie; Liu, Mengmei; Liu, Zhengwang

2013-04-10

306

Measurement of fast-neutron activation cross sections for copper, europium, hafnium, iron, nickel, silver, terbium and titanium at 10.0 and 14.7 MeV and for the Be( d, n) thick-target spectrum  

Microsoft Academic Search

Several fast-neutron activation reactions for copper, europium, hafnium, iron, nickel, silver, terbium and titanium that are important to fusion energy have been investigated in three distinct neutron fields generated by accelerators at Argonne National Laboratory (ANL) and Los Alamos National Laboratory (LANL), U.S.A., and Japan Atomic Energy Research Institute (JAERI), Tokai, Japan. The experimental data acquired from this collaboration, which

J. W. Meadows; D. L. Smith; L. R. Greenwood; R. C. Haight; Y. Ikeda; C. Konno

1996-01-01

307

Evaluation of Status of Zinc, Copper, and Iron Levels in Biological Samples of Normal Children and Children with Night Blindness with Age Groups of 3–7 and 8–12 Years  

Microsoft Academic Search

The causes of night blindness in children are multifactorial, and particular consideration has been given to childhood nutritional\\u000a deficiency, which is the most common problem found in underdeveloped countries. Such deficiency can result in physiological\\u000a and pathological processes that in turn influence hair composition. This study was designed to compare the levels of zinc\\u000a (Zn), copper (Cu), and iron (Fe)

Hassan Imran Afridi; Tasneem Gul Kazi; Naveed Kazi; Ghulam Abbas Kandhro; Jameel Ahmed Baig; Abdul Qadir Shah; Sham Kumar Wadhwa; Sumaira Khan; Nida Fatima Kolachi; Faheem Shah; Mohammad Khan Jamali; Mohammad Balal Arain; Sirajuddin

308

Analysis of Barium Clouds. Volume I.  

National Technical Information Service (NTIS)

Several aspects of the analysis of barium ion clouds are presented including ion cloud modeling, comparison of radar and optical data, and correlation of data with theory. A quantitative model has been developed from which various properties of barium ion...

B. Kivel L. F. Cianciolo L. M. Linson S. Powers

1972-01-01

309

Solid-state barium-vapor detector  

Microsoft Academic Search

The need for electrical switching devices for use in high-temperature radioactive environments in space nuclear power systems has led to the development of the cesium-barium tacitron. Effective evaluation of electrically insulating joints for the barium-cesium tacitron requires a method for the in situ detection of barium vapor which may leak through the joint. A solid-state barium-vapor detector has been developed

Jeffrey W. Fergus; S. Hui

1995-01-01

310

Correlations in distribution and concentration of calcium, copper and iron with zinc in isolated extracellular deposits associated with age-related macular degeneration.  

PubMed

Zinc (Zn) is abundantly enriched in sub-retinal pigment epithelial (RPE) deposits, the hallmarks of age-related macular degeneration (AMD), and is thought to play a role in the formation of these deposits. However, it is not known whether Zn is the only metal relevant for sub-RPE deposit formation. Because of their involvement in the pathogenesis of AMD, we determined the concentration and distribution of calcium (Ca), iron (Fe) and copper (Cu) and compared these with Zn in isolated and sectioned macular (MSD), equatorial (PHD) and far peripheral (FPD) sub-RPE deposits from an 86 year old donor eye with post mortem diagnosis of early AMD. The sections were mounted on Zn free microscopy slides and analyzed by microprobe synchrotron X-ray fluorescence (?SXRF). Metal concentrations were determined using spiked sectioned sheep brain matrix standards, prepared the same way as the samples. The heterogeneity of metal distributions was examined using pixel by pixel comparison. The orders of metal concentrations were Ca ? Zn > Fe in all three types of deposits but Cu levels were not distinguishable from background values. Zinc and Ca were consistently present in all deposits but reached highest concentration in MSD. Iron was present in some but not all deposits and was especially enriched in FPD. Correlation analysis indicated considerable variation in metal distribution within and between sub-RPE deposits. The results suggest that Zn and Ca are the most likely contributors to deposit formation especially in MSD, the characteristic risk factor for the development of AMD in the human eye. PMID:24740686

Flinn, Jane M; Kakalec, Peter; Tappero, Ryan; Jones, Blair; Lengyel, Imre

2014-06-25

311

DISTRIBUTION OF NATURAL AND ADDED COPPER AND 1RON IN MILK 1  

Microsoft Academic Search

SUMMARY A radioactive tracer was used to determine the distribution of copper in milk. For comparison, the distribution of radioactive iron also was determined. The method can readily distinguish the sources (natural or added) of copper or iron. Marked differences were observed in the distribution of natural and added copper. Naturally occurring copper was concentrated (ca. 10-35% of the copper)

R. L. KING; J. R. LUICK; I. I. LITMAN; W. G. JENNINGS; W. L. DUNKLEY

1958-01-01

312

The role of copper and iron ions in the ?-radiolysis of DNA. Part 1. EPR studies at cryogenic temperatures  

NASA Astrophysics Data System (ADS)

The ?-radiolysis of frozen aqueous solutions of DNA has been studied by EPR. The effect of transition metal ions Fe(III) and Cu(II) up to 5 mM concentration emerged in lowering of the total radical production in DNA. The loss of 5-thymyl radical rad TH was mainly observed (on annealing to 203 K) giving evidence that less radical anion of thymine was formed and that no electron transfer from C rad - to thymine was revealed in the system. Fe(III) ions are more efficient in the DNA protection than Cu(II) ions. The specific binding sites of iron ions appear to be thymine base.

Ambro?, H. B.; Kemp, T. J.; Kornacka, E. M.; Przybytniak, G. K.

1998-11-01

313

Relevance of the barium follow-through examination in the diagnosis of adult celiac disease  

Microsoft Academic Search

Significant changes on a standard barium follow-through examination in celiac disease have been determined by comparison with functional changes (irritable bowel syndrome), malabsorption without a villous lesion (chronic pancreatitis), and a villous abnormality without malabsorption (dermatitis herpetiformis). Patients with iron deficiency anemia formed the control group. Slight jejunal dilatation (26–30 mm) was found in 15% of the celiacs and 17%

Parveen Kumar; C. I. Bartram

1979-01-01

314

The occurrence of copper, iron, zinc and other elements and the nature of some copper and iron complexes in humic substances from municipal refuse disposed of in a landfill.  

PubMed

Municipal refuse was allowed to decompose in a simulated landfill for 20 months. Three different models were studied in which the refuse, in 40 m3 lots, was either compacted or mixed 2:1 with sewage sludge, the latter being studied in both uncompacted and compacted states. At 2, 6, 12 and 20 months, humic substances were extracted from samples with 0.1 M Na2P4O7 and 0.1 M NaOH, and humic acids isolated by precipitation after acidification with HCl. The humic substances were examined by electron paramagnetic resonance (EPR) to determine the free radical content and the nature of some of the metal complexes present. The principal form of copper was present in either a square planar or a tetragonally-distorted octahedral environment, probably coordinated to two nitrogen and two oxygen atoms. Fe3+ was present in at least three different environments. In one, it was probably in a complex with rhombic symmetry; another showed Fe3+ in an axially-symmetric environment, most likely as a ferric porphyrin. No distinctions could be made between the concentrations or forms of metals present in the refuse humic substances as a result of adding sewage sludge, but the additions increased the yield of humic substances, particularly in the uncompacted landfill. Humic substances in the refuse retain metal elements in complexed forms which will restrict their release from the landfill. PMID:2992079

Filip, Z; Cheshire, M V; Goodman, B A; McPhail, D B

1985-07-01

315

Effects of Partial Replacement of Iron with Tungsten on Microstructure, Electrical, Magnetic and Humidity Properties of Copper-Zinc Ferrite Material  

NASA Astrophysics Data System (ADS)

This paper presents the analysis of the influence of partial replacement of iron with tungsten on the properties of copper-zinc spinel ferrite material. The samples of Cu0.5Zn0.5W x Fe2-x O4 spinel powder ferrites were prepared by using a sol-gel self-combustion technology. The ferrite samples were treated for 30 min at 1000°C. The x-ray diffraction was used in order to establish the differences between the phase compositions of ferrites with different tungsten content. Scanning electron microscopy was used to highlight the influence of the tungsten content on the crystallites. All the samples of Cu0.5Zn0.5W x Fe2-x O4 were subject to investigation of the influence of the substitution of tungsten upon their electrical and magnetic properties. The measurements of the electrical properties were performed in different humidity conditions, in order to highlight the effect of moisture conditions on the electrical properties of the material and to analyze the applicability of Cu0.5Zn0.5W x Fe2-x O4 ferrite for resistive or capacitive humidity sensors.

Tudorache, Florin; Petrila, Iulian

2014-05-01

316

Stochastic statistical theory of nucleation and evolution of nano-sized precipitates in alloys with application to precipitation of copper in iron  

SciTech Connect

A consistent and computationally efficient stochastic statistical approach (SSA) is developed to study the kinetics of nucleation and evolution of nano-sized precipitates in alloys. To increase the accuracy of the method, many refinements of the previous simplified versions of this approach have been made. We consider a realistic vacancy-mediated exchange kinetics rather than the simplified direct-atomic-exchange model; use quantitative, cluster statistical methods rather than simple mean-field-type approximations; allow strong concentration and temperature dependences of generalized mobilities in the resulting kinetic equations; consider realistic alloy models based on first-principle calculations, and so on. We also introduce the 'maximum thermodynamic gain' principle to determine the key kinetic parameter of the SSA, the characteristic length of local equilibrium in the course of the nucleation process. For several realistic models of iron-copper alloys studied, the results of the SSA-based simulations of precipitation kinetics made in this work agree well with the kinetic Monte Carlo simulation results for all main characteristics of the microstructure. The approach developed is also used to study the kinetics of nucleation and changes in microstructural evolution under variations of temperature or concentration.

Khromov, K. Yu. [Russian Research Center 'Kurckatov Institute' (Russian Federation); Soisson, F. [DMN-SRMP, Service de Recherches de Metallurgie Physique (France); Stroev, A. Yu.; Vaks, V. G., E-mail: vaks@mbslab.kiae.ru [Russian Research Center 'Kurckatov Institute' (Russian Federation)

2011-03-15

317

Effect of genotype on micronutrient absorption and metabolism: a review of iron, copper, iodine and selenium, and folates.  

PubMed

For the majority of micronutrients, there are very little data, or none at all, on the role of genetic polymorphisms on their absorption and metabolism. In many cases, the elucidation of biochemical pathways and regulators of homeostatic mechanisms have come from studies of individuals that have mutations in certain genes. Other polymorphisms in these genes that result in a less severe phenotype may be important in determining the natural range of variation in absorption and metabolism that is commonly observed. To illustrate some of these aspects, I briefly review the increased understanding of iron metabolism that has arisen from our knowledge of the effects of mutations in several genes, the role of genetic variation in mediating the nutritional effects of iodine and selenium, and finally, the interaction between a genetic polymorphism in folate metabolism and folic acid fortification. PMID:18214022

Mithen, Richard

2007-05-01

318

Hydrogen bonding of sulfur ligands in blue copper and iron-sulfur proteins: detection by resonance raman spectroscopy  

SciTech Connect

The resonance Raman spectrum of the blue copper protein azurin from Alcaligenes denitrificans exhibits nine vibrational modes between 330 and 460 cm/sup -1/, seven of which shift 0.4-3.0 cm/sup -1/ to lower energy after incubation of the protein in D/sub 2/O. These deuterium-dependent shifts have been previously ascribed to exchangeable protons on imidazole ligands or to exchangeable protons on amide groups which are hydrogen bonded to the cysteine thiolate ligands (a feature common to all blue copper proteins of known structure). In order to distinguish between these two possibilities, a systematic investigation of Fe/sub 2/S/sub 2/(Cys)/sub 4/-containing proteins was undertaken. Extensive hydrogen bonding between sulfur ligands and the polypeptide backbone had been observed in the crystal structure of ferredoxin from Spirulina platensis. The resonance Raman spectrum of this protein is typical of a chloroplast-type ferredoxin and exhibits deuterium-dependent shifts of -0.3 to -0.5 cm/sup -1/ in the Fe-S modes at 283, 367, and 394 cm/sup -1/ and -0.6 to -0.8 cm/sup -1/ in the Fe-S modes at 328 and 341 cm/sup -1/. Considerably greater deuterium sensitivity is observed in the Raman spectra of spinach ferredoxin and bovine adrenodoxin, particularly for the symmetric stretching vibration of the Fe/sub 2/S/sub 2/ moiety at approx. 390 cm/sup -1/. This feature decreases of 9.8 and 1.1 cm/sup -1/, respectively, for the two oxidized proteins in D/sub 2/O and by 1.8 cm/sup -1/ for reduced adrenodoxin in D/sub 2/O. These results suggest that the bridging sulfido groups may be more extensively hydrogen bonded in spinach ferredoxin and adrenodoxin than in S. platensis ferredoxin, with a further increase in hydrogen-bond strength in the reduced form of adrenodoxin.

Mino, Y.; Loehr, T.M.; Wada, K.; Matsubara, H.; Sanders-Loehr, J.

1987-12-15

319

Formation of Nickel, Cobalt, Copper, and Iron Aluminates from ?- and ?-Alumina-Supported Oxides: A Comparative Study  

NASA Astrophysics Data System (ADS)

The rates of metal aluminate formation in MeO x/Al 2O 3systems ( Me=Ni, Co, Cu, Fe) at 500-1000°C in O 2or N 2atmospheres were compared, using both ?-Al 2O 3and ?-Al 2O 3substrates. Interfacial reaction to MeAl 2O 4was assessed using Rutherford backscattering spectrometry and X-ray diffraction. The lateral homogeneity of the samples was investigated using scanning electron microscopy. The spinel formation rate follows the sequence FeAl 2O 4copper aluminate was accompanied by a severe rupture of the top layer (˜1 ?m) of the substrate. Penetration of transition metal ions into ?-Al 2O 3substrates is notable at considerably lower temperatures than with ?-Al 2O 3substrates, mainly due to grain boundary diffusion. Annealing conditions that favor the formation of transition metal cations of a low valency (Co 2+, Cu +) are beneficial for reactions to aluminates.

Bolt, P. H.; Habraken, F. H. P. M.; Geus, J. W.

1998-01-01

320

Computer modelling of barium titanate  

Microsoft Academic Search

Barium titanate is an important material for both scientific and industrial applications. Much of the interest centres around its ferroelectric properties, since it is structurally the most simple in this class. In addition rare-earth doped ceramics are found to exhibit a very steep positive temperature coefficient of resistance (PTCR) above the Curie point. The theory of this PTCR effect is

G. V. Lewis; C. R. A. Catlow

1983-01-01

321

Recent Developments in Barium Borate,  

National Technical Information Service (NTIS)

The nonlinear optical properties of Beta-BaB2O4(beta barium borate) are demonstrated in the generation of second through fifth harmonics of 1.06-micrometer neodymium laser radiation, and in optical parametric oscillation pumped by 532-nm radiation. Beta-B...

C. Chen Y. X. Fan R. C. Eckardt R. L. Byer

1986-01-01

322

Nucleation Mechanisms in Ductile Iron  

Microsoft Academic Search

The present paper reviews different mechanisms for graphite nucleation in ductile iron (DI) and how these are affected by the inoculation process. Theories describing the fundamentals of graphite formation are given and the strengths and weaknesses of each theory discussed. Effects of key elements in the nucleation process, such as silicon (Si), calcium (Ca), strontium (Sr), barium (Ba), aluminum (Al),

T. Skaland

323

SAD phasing with in-house cu Ka radiation using barium as anomalous scatterer.  

PubMed

Phasing of lysozyme crystals using co-crystallized barium ions was performed using single-wavelength anomalous diffraction (SAD) method using Cu Ka radiation with in-house source of data collection. As the ion binding sites vary with respect to the pH of the buffer during crystallization, the highly isomorphic forms of lysozyme crystals grown at acidic and alkaline pH were used for the study. Intrinsic sulphur anomalous signal was also utilized with anomalous signal from lower occupancy ions for phasing. The study showed that to solve the structure by SAD technique, 2.8-fold data redundancy was sufficient when barium was used as an anomalous marker in the in-house copper X-ray radiation source for data collection. Therefore, co-crystallization of proteins with barium containing salt can be a powerful tool for structure determination using lab source. PMID:22329242

Dhanasekaran, V; Velmurugan, D

2011-12-01

324

Levels of lead, cadmium, copper, iron, and zinc in deciduous teeth of children living in Irbid, Jordan by ICP-OES: some factors affecting their concentrations.  

PubMed

The aim of this study was to measure the concentrations of lead (Pb), cadmium (Cd), copper (Cu), iron (Fe), and zinc (Zn) in deciduous teeth from children living in Jordan and to investigate the affecting factors. Deciduous teeth samples (n = 320, without fillings) were collected from 5- to 12-year-old children and analyzed for Pb, Cd, Cu, Fe, and Zn using inductively coupled plasma-optical emission spectrometry. A questionnaire was used to gather information on each child, such as sex, age, tooth type (incisors, canines, and molars), tooth position within the mouth (upper or lower jaw), caries status, presence of amalgam fillings inside the mouth, type of drinking water (tap water, home purified water, and plant purified water), and zone of residence (close to or far from heavy traffic roads). The mean concentrations of Pb, Cd, Cu, Fe, and Zn were 30.26, 0.55, 6.23, 34.72, and 128.21 ?g/g, respectively. Our results indicate that there is a clear relation between the concentrations of the metals analyzed in this study and tooth type, tooth position within the mouth, caries status, presence of amalgam fillings inside the mouth, and type of drinking water. No significant differences in the concentrations of the five metals analyzed were observed due to sex. Our results also show that no significant difference among Pb, Cd, Cu, Fe, and Zn concentrations and age among the ages of 5-6, 7-8, 9-10, and 11-12, except for Pb, which decreases at age 11-12. PMID:22851195

Alomary, A; Al-Momani, I F; Obeidat, S M; Massadeh, A M

2013-04-01

325

Lead, mercury, cadmium, chromium, nickel, copper, zinc, calcium, iron, manganese and chromium (VI) levels in Nigeria and United States of America cement dust.  

PubMed

This study was aimed at investigating the relative abundance of heavy metals in cement dust from different cement dust factories in order to predict their possible roles in the severity of cement dust toxicity. The concentrations of total mercury (Hg), copper (Cu), chromium (Cr), cadmium (Cd), nickel (Ni), manganese (Mn), lead (Pb), iron (Fe) and chromium (VI) (Cr (VI)) levels in cement dust and clinker samples from Nigeria and cement dust sample from the United States of America (USA) were determined using graphite furnace atomic absorption (GFAAS), while Zn and Ca were measured by flame atomic absorption spectrophotometry (FAAS), and Cr (VI) by colorimetric method. Total Cu, Ni and Mn were significantly higher in cement dust sample from USA (p<0.05), also, both total Cr and Cr (VI) were 5.4-26 folds higher in USA cement dust compared with Nigeria cement dust or clinker (p<0.001). Total Cd was higher in both Nigeria cement dust and clinker (p<0.05 and p<0.001), respectively. Mercury was more in both Nigeria cement dust and clinker (p<0.05), while Pb was only significantly higher in clinker from Nigeria (p<0.001). These results show that cement dust contain mixture of metals that are known human carcinogens and also have been implicated in other debilitating health conditions. Additionally, it revealed that metal content concentrations are factory dependent. This study appears to indicate the need for additional human studies relating the toxicity of these metals and their health impacts on cement factory workers. PMID:23261125

Ogunbileje, J O; Sadagoparamanujam, V-M; Anetor, J I; Farombi, E O; Akinosun, O M; Okorodudu, A O

2013-03-01

326

Flame atomic absorption spectrometric (FAAS) determination of copper, iron and zinc in food samples after solid-phase extraction on Schiff base-modified duolite XAD 761.  

PubMed

The present study involves the development of solid-phase extraction (SPE) procedure for the preconcentration of trace amounts of copper (Cu(2+)), iron (Fe(3+)) and zinc (Zn(2+)) ions on duolite XAD 761 modified by bis(2-hydroxyacetophenone)-2,2-dimethyl-1,3-propanediimine(BHAPDMPDI). The complexation between the metal ions and the proposed ligand was investigated potentiometrically. The metal ions retained on the sorbent were quantitatively determined via complexation with BHAPDMPDI. The complexed metal ions were efficiently eluted using 6 mL of 4 mol L(-1) nitric acid in acetone. The influences of the analytical parameters, including pH, amounts of the ligand and the solid phase, eluent conditions and sample volume, on the recoveries of the metal ions were optimized. Using the optimized parameters, the linear response of the SPE method for Cu(2+), Zn(2+) and Fe(3+) ions were in the ranges of 0.01-0.34, 0.01-0.28 and 0.02-0.31 ?g mL(-1), respectively, and the detection limits for Cu(2+), Zn(2+) and Fe(3+) ions were 1.8, 1.6 and 2.4 ?g mL(-1), respectively. The proposed method exhibits a preconcentration factor of 208 for all of the ions studied and an enhancement factor for Cu(2+), Fe(3+) and Zn(2+) ions of 34, 28 and 38, respectively. The presented results demonstrate the successful application of the proposed method for the determination of these metal ions in some real samples with high recoveries (> 95%) and reasonable relative standard deviation (RDS <5%). PMID:23498267

Ghaedi, M; Mortazavi, K; Montazerozohori, M; Shokrollahi, A; Soylak, M

2013-05-01

327

Opacity of iron, nickel, and copper plasmas in the x-ray wavelength range: theoretical interpretation of 2p-3d absorption spectra.  

PubMed

This paper deals with theoretical studies on the 2p-3d absorption in iron, nickel, and copper plasmas related to LULI2000 (Laboratoire pour l'Utilisation des Lasers Intenses, 2000J facility) measurements in which target temperatures were of the order of 20 eV and plasma densities were in the range 0.004-0.01 g/cm(3). The radiatively heated targets were close to local thermodynamic equilibrium (LTE). The structure of 2p-3d transitions has been studied with the help of the statistical superconfiguration opacity code SCO and with the fine-structure atomic physics codes HULLAC and FAC. A new mixed version of the sco code allowing one to treat part of the configurations by detailed calculation based on the Cowan's code RCG has been also used in these comparisons. Special attention was paid to comparisons between theory and experiment concerning the term features which cannot be reproduced by SCO. The differences in the spin-orbit splitting and the statistical (thermal) broadening of the 2p-3d transitions have been investigated as a function of the atomic number Z. It appears that at the conditions of the experiment the role of the term and configuration broadening was different in the three analyzed elements, this broadening being sensitive to the atomic number. Some effects of the temperature gradients and possible non-LTE effects have been studied with the help of the radiative-collisional code SCRIC. The sensitivity of the 2p-3d structures with respect to temperature and density in medium-Z plasmas may be helpful for diagnostics of LTE plasmas especially in future experiments on the ?n=0 absorption in medium-Z plasmas for astrophysical applications. PMID:22060513

Blenski, T; Loisel, G; Poirier, M; Thais, F; Arnault, P; Caillaud, T; Fariaut, J; Gilleron, F; Pain, J-C; Porcherot, Q; Reverdin, C; Silvert, V; Villette, B; Bastiani-Ceccotti, S; Turck-Chièze, S; Foelsner, W; de Gaufridy de Dortan, F

2011-09-01

328

Copper, zinc, and iron concentrations in blood serum and diet of dairy cattle on semi-industrial farms in central Iran.  

PubMed

The aim of this study was to evaluate the blood serum and diet concentrations of copper, zinc, and iron in Holstein dairy cattle kept under semi-industrial farming in Isfahan province, central Iran. Moreover, the effects of season, pregnancy, and daily milk yield on serum Cu, Zn, and Fe concentrations were also evaluated. The study was carried out on 12 semi-industrial Holstein dairy cattle farms. A total of 120 blood serum samples (60 in each season) and 24 diet samples (12 in each season) were collected in the summer and winter. The Cu, Fe, and Zn contents were assessed in samples using atomic absorption spectrophotometer. In the summer, the mean concentrations of Cu and Fe in serum samples were lower and higher than the critical level, respectively (P?

Noaman, Vahid; Rasti, Mohsen; Ranjbari, Ahmad Reza; Shirvani, Edris

2012-03-01

329

Oxidation resistant copper  

SciTech Connect

Oxidation resistant particles composed of copper and at least one metal having a valence of +2 or +3 and having an intermediate lattice energy for the metal in its hydroxide form. The metal is selected from nickel, cobalt, iron, manganese, cadmium, zinc, tin, magnesium, calcium and chromium. In one embodiment, the phases of copper and at least one metal in the particles are separate and the concentration of the metal is greater near the surface of the particles than inwardly thereof. Process for making the oxidation resistant copper particles includes the steps of dissolving a copper salt and a salt of at least one of the metals in a suitable solvent or diluent; forming primary particles of copper and at least one metal in basic form by mixing a base and the salt solution; separating, washing and drying the primary particles; reducing the primary particles to metallic form; and heat treating the particles in metallic form at an elevated temperature.

Edelstein, A.S.; Kaatz, F.H.; Harris, V.G.

1993-11-15

330

Copper Test  

MedlinePLUS

... copper in my diet? 1. Should everyone's copper metabolism be evaluated? General screening for copper concentrations is ... in Man and Animals, Genetic Defects in Copper Metabolism. J. Nutr . 133: 1527S-1531S [On-line journal ...

331

Cobalt distribution during copper matte smelting  

Microsoft Academic Search

Many smelter operators subscribe to the ``precautionary principle'' and wish to understand the behavior of the metals and impurities during smelting, especially how they distribute between product and waste phases and whether these phases lead to environmental, health, or safety issues. In copper smelting, copper and other elements are partitioned between copper matte, iron silicate slag, and possibly the waste

T. S. Kho; D. R. Swinbourne; T. Lehner

2006-01-01

332

40 CFR 721.10011 - Barium calcium manganese strontium oxide.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Barium calcium manganese strontium oxide. 721.10011...Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a...chemical substance identified as barium calcium manganese strontium oxide (PMN...

2013-07-01

333

40 CFR 721.10011 - Barium calcium manganese strontium oxide.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Barium calcium manganese strontium oxide. ...Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. ...The chemical substance identified as barium calcium manganese strontium...

2009-07-01

334

Development of efficient method for preconcentration and determination of copper, nickel, zinc and iron ions in environmental samples by combination of cloud point extraction and flame atomic absorption spectrometry  

Microsoft Academic Search

A cloud point extraction procedure for the preconcentration of copper, nickel, iron and zinc ions in various samples has been\\u000a described. Analyte ions in aqueous phase are complexed with 3-((indolin-3-yl)(phenyl)methyl)indoline (IYPMI) and following\\u000a centrifugation quantitatively extracted to the aqueous phase rich in Triton X-114. The surfactant-rich phase was dissolved\\u000a in 2.0 mol L?1 HNO3 in methanol prior to metal content

Mehrorang Ghaedi; Ardeshir Shokrollahi; Khodabakhsh Niknam; Ebrahim Niknam; Mustafa Soylak

2009-01-01

335

75 FR 20625 - Barium Chloride From China  

Federal Register 2010, 2011, 2012, 2013

...INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-149 (Third Review)] Barium Chloride From China AGENCY: United States International Trade Commission. ACTION: Revised schedule for the subject...

2010-04-20

336

The Intec Copper Process: A Detailed Environmental Analysis  

Microsoft Academic Search

The Intec Copper Process is an environmentally advantageous hydrometallurgical process for the production of high purity copper and associated precious metals from copper sulphide concentrates. The process uses a mixed chloride-bromide lixiviant in an elegant cyclic circuit to leach the copper into solution, rejecting the iron as stable hematite rather than as unstable jarosite. After purification of the pregnant liquor,

D Sammut; N J Welham

337

Spatial and temporal zoning of hydrothermal alteration and mineralization in the Sossego iron oxide-copper-gold deposit, Carajás Mineral Province, Brazil: paragenesis and stable isotope constraints  

NASA Astrophysics Data System (ADS)

The Sossego iron oxide-copper-gold deposit (245 Mt @ 1.1% Cu, 0.28 g/t Au) in the Carajás Mineral Province of Brazil consists of two major groups of orebodies (Pista-Sequeirinho-Baiano and Sossego-Curral) with distinct alteration assemblages that are separated from each other by a major high angle fault. The deposit is located along a regional WNW-ESE-striking shear zone that defines the contact between metavolcano-sedimentary units of the ˜2.76 Ga Itacaiúnas Supergroup and tonalitic to trondhjemitic gneisses and migmatites of the ˜2.8 Ga Xingu Complex. The deposit is hosted by granite, granophyric granite, gabbro, and felsic metavolcanic rocks. The Pista-Sequeirinho-Baiano orebodies have undergone regional sodic (albite-hematite) alteration and later sodic-calcic (actinolite-rich) alteration associated with the formation of massive magnetite-(apatite) bodies. Both these alteration assemblages display ductile to ductile-brittle fabrics. They are cut by spatially restricted zones of potassic (biotite and potassium feldspar) alteration that grades outward to chlorite-rich assemblages. The Sossego-Curral orebodies contain weakly developed early albitic alteration and very poorly developed subsequent calcic-sodic alteration. These orebodies contain well-developed potassic alteration assemblages that were formed during brittle deformation that resulted in the formation of breccia bodies. Breccia matrix commonly displays coarse mineral infill suggestive of growth into open space. Sulfides in both groups of deposits were precipitated first with potassic alteration and more importantly with a later assemblage of calcite-quartz-epidote-chlorite. In the Sequeirinho orebodies, sulfides range from undeformed to deformed; sulfides in the Sossego-Curral orebodies are undeformed. Very late, weakly mineralized hydrolytic alteration is present in the Sossego/Currral orebodies. The sulfide assemblage is dominated by chalcopyrite with subsidiary siegenite, and millerite. Pyrrhotite and pyrite are minor constituents of ore in the Sequerinho orebodies while pyrite is relatively abundant in the Sossego-Curral bodies. Oxygen isotope partitioning between mineral pairs constrains temperatures in the deposit spatially and through time. In the Sequeirinho orebody, the early sodic-calcic alteration stage was characterized by temperatures exceeding 500°C and ? ^{{{text{18}}}} {text{O}}_{{{text{H}}_{{text{2}}} {text{O}}}} values for the alteration fluid of 6.9 ± 0.9‰. Temperature declines outward and upward from the zone of most intense alteration. Paragenetically later copper-gold mineralization displays markedly lower temperatures (<300°C) and was characterized by the introduction of 18O-depleted hydrothermal fluids -1.8 ± 3.4‰. The calculated ?DH2O and ? ^{{{text{18}}}} {text{O}}_{{{text{H}}_{{text{2}}} {text{O}}}} values suggest that the fluids that formed the early calcic-sodic alteration assemblage were of formational/metamorphic or magmatic origin. The decrease of ? ^{{{text{18}}}} {text{O}}_{{{text{H}}_{{text{2}}} {text{O}}}} values through time may reflect influx of surficially derived waters during later alteration and mineralization events. Influx of such fluids could be related to episodic fluid overpressure, resulting in dilution and cooling of the metalliferous fluid, causing deposition of metals transported as metal chloride complexes.

Monteiro, Lena V. S.; Xavier, Roberto P.; de Carvalho, Emerson R.; Hitzman, Murray W.; Johnson, Craig A.; de Souza Filho, Carlos Roberto; Torresi, Ignácio

2008-02-01

338

Calcite/barium fluoride ultraviolet polarizing prism  

NASA Astrophysics Data System (ADS)

A calcite/barium fluoride polarizing prism gives improved ultraviolet transmittance compared with a calcite/calcite ultraviolet polarizing prism. Beam spatial distortion is transmitted because of variations in absorption (and path length) in the calcite half of the calcite/barium fluoride prism.

Wu, Fuquan; Li, Guohua; Huang, Jiayin; Yu, Dehong

1995-07-01

339

Barium granuloma of the transverse colon.  

PubMed Central

A case of barium sulphate granuloma of the transverse colon following gunshot wounds to the abdomen has been described. Scanning electron microscopy with electron probe microanalysis was used to confirm the presence of barium sulphate and the absence of lead or other elements related to the gunshot wounds. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4

McKee, P. H.; Cameron, C. H.

1978-01-01

340

REMOVAL OF BARIUM AND RADIUM FROM GROUNDWATER  

EPA Science Inventory

A research project was undertaken to investigate processes for removing barium and radium from drinking water. Special emphasis was placed on ion exchange processes that can be used without adding large concentrations of sodium to the water. The wastes from radium and barium remo...

341

Evaluation of status of zinc, copper, and iron levels in biological samples of normal children and children with night blindness with age groups of 3-7 and 8-12 years.  

PubMed

The causes of night blindness in children are multifactorial, and particular consideration has been given to childhood nutritional deficiency, which is the most common problem found in underdeveloped countries. Such deficiency can result in physiological and pathological processes that in turn influence hair composition. This study was designed to compare the levels of zinc (Zn), copper (Cu), and iron (Fe) in scalp hair, blood, and urine of both genders of children with night blindness with age range of 3-7 and 8-12 years, comparing them to sex- and age-matched controls. A microwave-assisted wet acid digestion procedure was developed as a sample pretreatment, for the determination of zinc, copper, and iron in biological samples of children with night blindness. The proposed method was validated by using conventional wet digestion and certified reference samples of hair, blood, and urine. The digests of all biological samples were analyzed for Cu, Fe, and Zn by flame atomic absorption spectrometry using an air/acetylene flame. The results indicated significantly lower levels of Fe, Cu, and Zn in the biological samples (blood and scalp hair) of male and female children with night blindness, compared with control subjects of both genders. These data present guidance to clinicians and other professionals investigating the deficiency of essential trace metals in biological samples (scalp hair and blood) of children with night blindness. PMID:20686870

Afridi, Hassan Imran; Kazi, Tasneem Gul; Kazi, Naveed; Kandhro, Ghulam Abbas; Baig, Jameel Ahmed; Shah, Abdul Qadir; Wadhwa, Sham Kumar; Khan, Sumaira; Kolachi, Nida Fatima; Shah, Faheem; Jamali, Mohammad Khan; Arain, Mohammad Balal; Sirajuddin

2011-09-01

342

Cloud point extraction of copper, lead, cadmium, and iron using 2,6-diamino-4-phenyl-1,3,5-triazine and nonionic surfactant, and their flame atomic absorption spectrometric determination in water and canned food samples.  

PubMed

A cloud point extraction procedure was optimized for the separation and preconcentration of lead(II), cadmium(II), copper(II), and iron(III) ions in various water and canned food samples. The metal ions formed complexes with 2,6-diamino-4-phenyl-1,3,5-triazine that were extracted by surfactant-rich phases in the nonionic surfactant Triton X-114. The surfactant-rich phase was diluted with 1 M HNO3 in methanol prior to its analysis by flame atomic absorption spectrometry. The parameters affecting the extraction efficiency of the proposed method, such as sample pH, complexing agent concentration, surfactant concentration, temperature, and incubation time, were optimized. LOD values based on three times the SD of the blank (3Sb) were 0.38, 0.48, 1.33, and 1.85 microg/L for cadmium(II), copper(II), lead(II), and iron(III) ions, respectively. The precision (RSD) of the method was in the 1.86-3.06% range (n=7). Validation of the procedure was carried out by analysis of National Institute of Standards and Technology Standard Reference Material (NIST-SRM) 1568a Rice Flour and GBW 07605 Tea. The method was applied to water and canned food samples for determination of metal ions. PMID:22970587

Citak, Demirhan; Tuzen, Mustafa

2012-01-01

343

Copper Peroxide.  

National Technical Information Service (NTIS)

The action of hydrogen superoxide on copper salts in alcoholic solutions is studied. The action of hydrogen peroxide on copper hydroxide in alcoholic suspensions, and the action of ethereal hydrogen peroxide on copper hydroxide are discussed. It is conclu...

L. Moser

1988-01-01

344

Effets thermoelectrique et thermomagnetique du yttrium barium copper oxide monocristallin  

NASA Astrophysics Data System (ADS)

Des la decouverte des supraconducteurs a haute temperature critique, les recherches se sont intensifiees afin de comprendre les mecanismes qui sont a l'origine des proprietes de ces materiaux L'etat mixte, tout comme l'etat supraconducteur pur et l'etat normal, a fait l'objet de nombreux travaux de recherche. En particulier, la structure des vortex a l'etat mixte, et leur mouvement sous l'effet d'une force quelconque, etaient et restent le centre de preoccupation. Les effets thermoelectrique (Seebeck) et thermomagnetique (Nernst) sont parmi les differentes mesures qui peuvent donner de l'information sur les etats des vortex a l'etat mixte. L'avantage essentiel de ces deux effets est l'absence d'un courant electrique applique. Ce dernier peut donner des perturbations indesirables durant les mesures. D'autre pari, nous avons utilise la methode CA (Courant Alternatif) pour effectuer nos mesures. Cette methode est caracterisee par une meilleure resolution par rapport a la methode CC (Courant Continu) conventionnelle. Nous avons etudie autant des echantillons macles que des echantillons sans macles. D'abord nous avons teste notre montage a champ magnetique nul. Nous avons alors montre que le pic rapporte par certains dans l'effet Seebeck a la transition supraconductrice ne correspond pas a une realite physique mais a un artefact experimental. On avait associe ce pic aux fluctuations. Par la suite, nous avons mis en evidence et etudie pour la premiere fois avec les effets Seebeck et Nernst le phenomene de la fusion du reseau de vortex grace a des mesures sur les echantillons sans macles. Cette etude s'est faite pour deux concentrations d'oxygene differentes et pour un gradient de temperature parallele, consecutivement, aux deux axes cristallographiques dans le plan ab. Finalement, nous avons etudie l'effet des plans de maclage sur le mouvement des vortex. Ceci a ete realise en appliquant le gradient de temperature selon trois directions differentes (0, 45 et 90°) avec les plans de maclage. Nous avons observe, pour le premier angle un mouvement libre du vortex, pour le second angle une contribution de l'effet Nernst a l'effet Seebeck et pour la troisieme direction un phenomene d'activation. Dans ce dernier cas, les plans de maclage font un obstacle qui s'oppose au mouvement des vortex. De ce qui precede, nous concluons qu'avec la bonne resolution de notre technique nous sommes capables d'observer des phenomenes que la technique CC ne met pas en relief. D'autre part, la variete d'echantillons que nous avons etudies et les phenomenes que nous avons observes valorisent la presente etude.

Ghamlouche, Hassan

1998-09-01

345

Method for harvesting rare earth barium copper oxide single crystals  

DOEpatents

A method of preparing high temperature superconductor single crystals is disclosed. The method of preparation involves preparing precursor materials of a particular composition, heating the precursor material to achieve a peritectic mixture of peritectic liquid and crystals of the high temperature superconductor, cooling the peritectic mixture to quench directly the mixture on a porous, wettable inert substrate to wick off the peritectic liquid, leaving single crystals of the high temperature superconductor on the porous substrate. Alternatively, the peritectic mixture can be cooled to a solid mass and reheated on a porous, inert substrate to melt the matrix of peritectic fluid while leaving the crystals melted, allowing the wicking away of the peritectic liquid. 2 figs.

Todt, V.R.; Sengupta, S.; Shi, D.

1996-04-02

346

New barium ferrite particles: Spherical shape  

NASA Astrophysics Data System (ADS)

Pure and ZnTi-doped spherical barium ferrite particles were prepared using two different methods: semicoprecipitation and ultrasonic spray pyrolysis. The ultrasonic spray pyrolysis method was more effective in controlling particle shape. Particle size was in between 0.27 and 0.3 ?m. Coercivity and saturation magnetization were in the range of 1000 to 5000 Oe and 49 to 53 emu/g, respectively. Crystallization of amorphous Ba-Fe-O spherical precursors occurs at a lower temperature than Ba-Fe-Zn-Ti-O precursors. ?M measurement shows that magnetic interaction in spherical barium ferrite tape is weaker than hexagonal platelet barium ferrite.

Hong, Y. K.; Jung, H. S.

1999-04-01

347

Photorefractive and Photochromic Effects in Barium Titanate.  

National Technical Information Service (NTIS)

Nominally undoped p-type Barium titanate was grown that exhibits interesting intensity dependent photorefractive and photochromic properties. When its photochromism is activated the absorption increases at the activating wavelength and there is a concurre...

C. Warde H. P. Jenssen J. Y. Chang M. H. Garrett T. M. Pollak

1992-01-01

348

Barium Isotopes in Single Presolar Grains  

NASA Technical Reports Server (NTRS)

Barium isotopic compositions of single presolar grains were measured by laser ablation laser resonant ionization mass spectrometry and the implications of the data for stellar processes are discussed. Additional information is contained in the original extended abstract.

Pellin, M. J.; Davis, A. M.; Savina, M. R.; Kashiv, Y.; Clayton, R. N.; Lewis, R. S.; Amari, S.

2001-01-01

349

Chemically Modified Carbon Electrodes. XVII. Metallation of Immobilized Tetra(Aminophenyl)Porphyrin with Manganese, Iron, Nickel, Copper and Zinc, and Electrochemistry of Diprotonated Tetraphenylporphyrin.  

National Technical Information Service (NTIS)

Tetra(aminophenyl)porphyrin can be amide-bonded to oxidized glassy carbon surfaces following activation with acetyl chloride or thionyl chloride, with the latter affording higher coverage. The immbolized porphyrin can be metallated with manganese, iron, c...

R. D. Rocklin R. W. Murray

1979-01-01

350

Sulfur Dioxide Removal from Flue Gases by Supported Copper and Iron Absorbents: Technical Report No. 6, November 16, 1987-February 15, 1988.  

National Technical Information Service (NTIS)

Significant progress has been achieved on the preparation, characterization and evaluation of CuAl2O3 sorbents for SO2 sorption. By using the extraction technique, sorbents have been prepared that contain copper incorporated into the alumina support witho...

G. A. Melson

1988-01-01

351

Processing of Cobalt-Copper-Arsenic Complex Ore Concentrate  

Microsoft Academic Search

Extraction of cobalt from complex ore flotation concentrates obtained from the Blackbird Mine. Idaho. USA is reviewed. After flotation of a primary copper concentrate, a bulk concentrate is recovered containing major amounts of cobalt, arsenic, and iron, with minor amounts of copper and nickel. This concentrate can be upgraded during flotation by removing iron, but with considerable cobalt loss. Chemical

ROBERT W. BARTLETT

1995-01-01

352

Surface films and corrosion of copper.  

National Technical Information Service (NTIS)

In Sweden and Finland the spent nuclear fuel is planned to be encapsulated in cast iron canisters that have an outer shield made of copper. The copper shield is responsible for the corrosion protection of the canister construction. General corrosion of th...

J. Hilden T. Laitinen K. Maekelae T. Saario M. Bojinov

1999-01-01

353

Recovery of scrap iron metal value using biogenerated ferric iron.  

PubMed

The utility of employing biogenerated ferric iron as an oxidant for the recycling of scrap metal has been demonstrated using continuously growing cells of the extremophilic organism Acidithiobacillus ferrooxidans. A ferric iron rich (70 mol%) lixiviant resulting from bioreactor based growth of A. ferrooxidans readily solubilized target scrap metal with the resultant generation of a leachate containing elevated ferrous iron levels and solubilized copper previously resident in the scrap metal. Recovery of the copper value was easily accomplished via a cementation reaction and the clarified leachate containing a replenished level of ferrous iron as growth substrate was shown to support the growth of A. ferrooxidans and be fully recyclable. The described process for scrap metal recycling and copper recovery was shown to be efficient and economically attractive. Additionally, the utility of employing the E(h) of the growth medium as a means for monitoring fluctuations in cell density in cultures of A. ferrooxidans is demonstrated. PMID:16440341

Ballor, Nicholas R; Nesbitt, Carl C; Lueking, Donald R

2006-04-20

354

Synthesis and structural characterization of new copper complexes and the copper-barium-alkoxide complex BaCu[sub 4](OC(R)C(H)C(R)O)[sub 4](OR[prime])[sub 2](HOR[prime])[sub 4] (R = C(CH[sub 3])[sub 3], R[prime] = CH[sub 2]CH[sub 2]OCH[sub 3])  

SciTech Connect

A series of new copper complexes [(thd)Cu(OMe)][sub 4] (4), [(tfd)Cu(OMe)][sub 4] (5) [(hfd)Cu(OMe)][sub 4] (6), [(thd)Cu(OPr[sup i])][sub 2] (7), [(tfd)Cu(OPr[sup i])][sub 2] (8), [(thd)Cu(OPh[sub f])][sub 2] (9), [(tfd)Cu(OPh[sub f])][sub 2] (10) [(hfd)Cu(OPh[sub f])] [sub 2] (11), [(thd)Cu(OCH[sub 2]CH[sub 2]OMe)][sub 4] (12), [(tfd)Cu(OCH[sub 2]CH[sub 2]OMe)][sub 4] (13), and [(hfd)Cu(OCH[sub 2]CH[sub 2]OMe)][sub 4] (14) (where thd, tfd, and hfd are the 2,2,6,6-tetramethyl-3,5-heptanedionato-,1,1,1-trifluoro-2,4-pentanedionato-, and 1,1,1,5,5,5-hexafluoro-2,4-pentanedionato ligands, respectively) were synthesized by using a [beta]-diketonate/alkoxide exchange method. Compounds 6, 10, 12, 14 were characterized by single-crystal X-ray diffraction. 6 and 10 exist as labile THF adducts with four and two THF molecules coordinated to the Cu atoms, respectively. Complex 10 has a centrosymmetric dimeric structure, and complexes 6 and 14 (crystallographic D[sub 2] and C[sub 2] symmetry, respectively) represent a cubane-type tetranuclear structure, in which four expanded parallel Cu[center dot][center dot][center dot]O bonds are observed. Complex 12 (C[sub i] symmetry) also contains a tetranuclear unit but belongs to a group of ladderlike structures with two stronger and two weaker Cu[center dot][center dot][center dot]O contacts. Starting from 12, the mixed-metal complex 15 was obtained, which was characterized by X-ray single crystal diffractometry. Complex 15 contains one Ba and four Cu atoms and has approximate C[sub 2] symmetry. A unifying approach was applied for the description of the frameworks of 15, the related Ba, Cu complex 18, and the high-[Tc] superconductor 19 in terms of common elementary building blocks. 25 refs., 9 figs., 16 tabs.

Bidell, W.; Shklover, V.; Berke, H. (Univ. of Zuerich (Switzerland))

1992-12-23

355

Cobalt distribution during copper matte smelting  

Microsoft Academic Search

Many smelter operators subscribe to the “precautionary principle” and wish to understand the behavior of the metals and impurities\\u000a during smelting, especially how they distribute between product and waste phases and whether these phases lead to environmental,\\u000a health, or safety issues. In copper smelting, copper and other elements are partitioned between copper matte, iron silicate\\u000a slag, and possibly the waste

T. S. Kho; D. R. Swinbourne; T. Lehner

2006-01-01

356

Cytotoxicity of synthetic barium hydroxyapatite.  

PubMed

Barium hydroxyapatite (Ba10(PO4)6(OH)2, Ba-HAp) was synthesized by a wet method using Ba(OH)2.8H2O and (NH4)2HPO4 as starting materials. The Ba-HAp obtained had a Ba/P atomic ratio of 1.76 and contained CO3 groups. The Ba-HAp was sintered at 1073 K for 12 hours. The sintered Ba-HAp had a three point bending strength of 29 MPa and Young's modulus of 27 GPa. Cytotoxicity of the sintered bodies and particles was tested using L-cells. The sintered Ba-HAp showed no cytotoxicity, and the cells were closely in contact with the surfaces of sintered Ba-HAp. Morphological observation of the cell around the Ba-HAp particles also showed no cytotoxicity. However, cell growth was inhibited by Ca adsorption on the Ba-HAp particles. These results suggested that the Ba-HAp had no cytotoxicity and can be applied as a bioactive X-ray opaque material. PMID:9138651

Kikuchi, M; Yamazaki, A; Akao, M; Aoki, H

1996-01-01

357

The ubiquity of iron.  

PubMed

The importance of iron in living systems can be traced to the many complexes within which it is found, to its chemical mobility in undergoing oxidation-reduction reactions, and to the abundance of iron in Earth's crust. Iron is the most abundant element, by mass, in the Earth, constituting about 80% of the inner and outer cores of Earth. The molten outer core is about 8000 km in diameter, and the solid inner core is about 2400 km in diameter. Iron is the fourth most abundant element in Earth's crust. It is the chemically functional component of mononuclear iron complexes, dinuclear iron complexes, [2Fe-2S] and [4Fe-4S] clusters, [Fe-Ni-S] clusters, iron protophorphyrin IX, and many other complexes in protein biochemistry. Metals such as nickel, cobalt, copper, and manganese are present in the crust and could in principle function chemically in place of iron, but they are scarce in Earth's crust. Iron is plentiful because of its nuclear stability in stellar nuclear fusion reactions. It seems likely that other solid planets, formed by the same processes as Earth, would also foster the evolution of life and that iron would be similarly important to life on those planets as it is on Earth. PMID:22845493

Frey, Perry A; Reed, George H

2012-09-21

358

Copper-promoted reductive homocoupling of quasi-aromatic iron(II) clathrochelates: boosting the inhibitory activity in a transcription assay.  

PubMed

A copper-promoted reductive homocoupling reaction, for the first time used for a metal complex, allowed obtaining a new kind of complexes with the encapsulated metal ions, C-C conjugated bis-clathrochelates. These compounds demonstrate extremely high transcription inhibition activity in the T7 RNA polymerase system with values of IC50 reaching as low as the submicromolar range, which places them among the most potent metal-based transcription inhibitors. PMID:24516860

Varzatskii, O A; Novikov, V V; Shulga, S V; Belov, A S; Vologzhanina, A V; Negrutska, V V; Dubey, I Y; Bubnov, Yu N; Voloshin, Ya Z

2014-03-25

359

The oxidation states of copper and iron in mineral sulfides, and the oxides formed on initial exposure of chalcopyrite and bornite to air  

Microsoft Academic Search

Metal L2,3, sulfur K and oxygen K near-edge X-ray absorption fine structure (NEXAFS) spectra for chalcopyrite, bornite, chalcocite, covellite, pyrrhotite and pyrite have been determined from single-piece natural mineral specimens in order to assess claims that chalcopyrite should be regarded as CuIIFeIIS2 rather than CuIFeIIIS2, and that copper oxide species are the principal initial oxidation products on chalcopyrite and bornite

Siew Wei Goh; Alan N. Buckley; Robert N. Lamb; Richard A. Rosenberg; Damian Moran

2006-01-01

360

Research on Thermionic Converters Using Barium and Cesium Vapor.  

National Technical Information Service (NTIS)

Investigations of thermionic converter operations were conducted utilizing a dual vapor system of barium and cesium. Barium and cesium vapors were introduced into two differently designed converters. The first converter developed an internal short circuit...

J. D. Long

1967-01-01

361

Drinking Water Criteria Document for Barium (Final Draft), December 1987.  

National Technical Information Service (NTIS)

The Office of Drinking Water, Environmental Protection Agency has prepared a Drinking Water Criteria Document on barium. The Criteria Document is an extensive review of the following topics: Physical chemical properties of Barium; Toxicokinetics and human...

1987-01-01

362

Drinking Water Criteria Document for Barium (Final Draft).  

National Technical Information Service (NTIS)

The Office of Drinking Water (ODW), U.S. Environmental Protection Agency has prepared a Drinking Water Criteria Document on barium. This Criteria Document is an extensive review of the following topics: Physical and chemical properties of barium; Toxicoki...

1985-01-01

363

Placement of Radium/Barium Sludges in Tailings Areas.  

National Technical Information Service (NTIS)

Currently radium is removed from uranium mining and milling effluents by the addition of barium chloride to precipitate the radium as radium/barium sulphate. The precipitate is allowed to settle in sedimentation basins prior to discharge of the effluent. ...

K. L. Murphy G. E. Multamaki

1980-01-01

364

Polaronic conduction in barium borate glasses containing iron oxide  

Microsoft Academic Search

The conductivity of xFe2O3·(60?x)BaO·40B2O3 glasses can be described using Mott's models for the small polaron hopping and variable-range hopping processes. The change of resistivity and activation energy with composition indicates that the conduction process varies from ionic to polaronic one. The activation energy is the predominant parameter that affects the conductivity with composition. The calculated values of the conductivity parameters

E. Mansour; G. M. El-Damrawi; Y. M. Moustafa; S. Abd El-Maksoud; H. Doweidar

2001-01-01

365

Preparation and Properties of Barium Titanate Nanopowder\\/Epoxy Composites  

Microsoft Academic Search

This article is focused on the preparation of barium titanate nanopowder\\/epoxy composites and studying the effect of barium titanate nanopowder on improving mechanical and thermal characteristics of the epoxy polymer. Composites are prepared by dispersing barium titanate nanopowder in epoxy resin and, subsequently, cross-linking by using diamino diphenyl methane (DDM) curing agents. Synthesis of barium titanate nanopowder\\/epoxy composites is carried

J. Chandradass; Dong-sik Bae

2008-01-01

366

Johntomaite, a new member of the bjarebyite group of barium phosphates: description and structure refinement  

Microsoft Academic Search

Summary   Johntomaite, ideally BaFe2+\\u000a 2Fe3+\\u000a 2(PO4)3(OH)3, is the Fe2+-analogue of perloffite and represents a new member of the bjarebyite group of barium phosphates. It occurs as an extremely\\u000a rare mineral on the dumps of the Spring Creek copper mine near Wilmington in the southern Flinders Ranges of South Australia,\\u000a where it forms clusters of greenish black, monoclinic prisms 0.3 to

U. Kolitsch; A. Pring; E. R. T. Tiekink

2000-01-01

367

Dielectric characteristics of barium strontium titanate films prepared by aerosol deposition on a Cu substrate  

Microsoft Academic Search

Polycrystalline barium strontium titanate (BaxSr1-xTiO3, BST) films were directly prepared on copper substrates using an aerosol deposition method (ADM) at room temperature. Electric properties, such as the dielectric constant and tunability, were investigated as a function of the Ba content in BaxSr1-xTiO3 (x = 1.0, 0.6, 0.4) films. At a frequency of 100 kHz, the dielectric constant of the as-deposited

Sewoong Oh; Jae-Hyuk Park; Jun Akedo

2009-01-01

368

Synthesis of barium titanate nanopowder using polymeric precursor method  

Microsoft Academic Search

Barium titanate powder was prepared by a polymerized complex method based on the Pechini type reaction route, where barium and titanium ions were polymerized in mixed solution of citric acid, ethylene glycol, to form a transparent resin, which was used as a precursor. Barium titanate powder was formed by heat treating the polymeric precursor in air at 500–900°C. The thermal

V. Vinothini; Paramanand Singh; M. Balasubramanian

2006-01-01

369

Conditions of preparation of calcium and barium hexaboride powders  

Microsoft Academic Search

1.A study was made of the conditions of preparation of barium and calcium hexaborides by the boroncarbide and borothermic techniques and by the reaction of barium carbonate with boron in a vacuum.2.It was established that a barium hexaboride with a composition approaching theoretical can be obtained by the borothermic techniques at a temperature of 1600°C from a charge with a

T. I. Serebryakova; É. V. Marek

1969-01-01

370

Barium iodide single-crystal scintillator detectors  

SciTech Connect

We find that the high-Z crystal Barium Iodide is readily growable by the Bridgman growth technique and is less prone to crack compared to Lanthanum Halides. We have grown Barium Iodide crystals: undoped, doped with Ce{sup 3+}, and doped with Eu{sup 2+}. Radioluminescence spectra and time-resolved decay were measured. BaI{sub 2}(Eu) exhibits luminescence from both Eu{sup 2+} at 420 nm ({approx}450 ns decay), and a broad band at 550 nm ({approx}3 {micro}s decay) that we assign to a trapped exciton. The 550 nm luminescence decreases relative to the Eu{sup 2+} luminescence when the Barium Iodide is zone refined prior to crystal growth. We also describe the performance of BaI{sub 2}(Eu) crystals in experimental scintillator detectors.

Cherepy, N

2007-07-30

371

Improved spectrophotometric analysis of barium styphnate  

SciTech Connect

A spectrophotometric procedure to determine the purity of barium styphnate monohydrate based upon the absorbance of the styphnate ion at 326 and 413.3 nm has been developed. The purity is determined by comparing the absorbance of the styphnate ion in barium styphnate and in styphnic acid. Our investigation has shown that the molar absorptivity and lambda maxima of the styphnate ion are quite pH dependent; therefore, the pH is buffered to 6.8 to 7.0 with ammonium acetate. Under these conditions the molar absorptivity is 1.6 x 10/sup 4/ L/mol-cm. Analyses following the procedure in the Navy specification WS13444A using water were found to give low molar absorptivities (1.3 x 10/sup 4/ L/mol-cm) for the styphnic acid calibration resulting in erroneous values for barium styphnate purity.

Brown, N E; Blasi, J A

1983-01-01

372

Examination of sulfur-functionalized, copper-doped iron nanoparticles for vapor-phase mercury capture in entrained-flow and fixed-bed systems  

SciTech Connect

The use of copper-doped Fe nanoaggregates silanized with organic sulfur as bis-(triethoxy silyl propyl)-tetra sulfide has been investigated for the capture of elemental mercury (Hg{sup 0}) from the vapor phase for potential power plant applications. Silanization procedures resulted in 70% deposition of the targeted sulfur level, with particles containing approximately 4 wt % S. The addition of copper was found to increase the fixed-bed (total) capacity of this type of sorbent from 170 {+-} {mu}20 g Hg{center_dot}g sorbent{sup -1} with no copper doping to 2730 {+-} 80 {mu}g Hg{center_dot}g sorbent{sup -1} at 1.2 wt % Cu. When no S is deposited, the capacity of Fe/Cu nanoaggregates was only 180 g Hg{center_dot}g sorbent{sup -1}. These findings suggest that a combined Cu-S mechanism is responsible for Hg capture. Moving-bed (injection) testing of the Fe-based sorbents in a simulated flue gas stream showed that the 1.2 wt % Cu sample was able to achieve significant removal of the Hg. At a modest sorbent injection rate of 3.6 x 10{sup -3} g{center_dot}L{sup -1}{center_dot}h{sup -1}, this material showed a steady-state removal capacity of 107.5 {mu}g Hg{center_dot}g sorbent{sup -1} for an inlet concentration of 17.8 {mu}g{center_dot}m{sup -3}. On the basis of only 4% usage of the total capacity during single-pass injection, it might be beneficial to develop methods to separate and recycle these materials to reduce power plant operation costs for Hg emissions control. 17 refs., 5 figs., 10 tabs.

D.E. Meyer; S.K. Sikdar; N.D. Hutson; D. Bhattacharyya [University of Kentucky, Lexington, KY (United States). Department of Chemical and Materials Engineering

2007-09-15

373

Adaptation of Aerobically Growing Pseudomonas aeruginosa to Copper Starvation  

Microsoft Academic Search

Restricted bioavailability of copper in certain environments can interfere with cellular respiration because copper is an essential cofactor of most terminal oxidases. The global response of the metabolically versatile bacterium and opportunistic pathogen Pseudomonas aeruginosa to copper limitation was assessed under aerobic conditions. Expression of cioAB (encoding an alternative, copper-independent, cyanide-resistant ubiquinol oxidase) was upregulated, whereas numerous iron uptake functions

Emanuela Frangipani; Vera I. Slaveykova; Cornelia Reimmann; Dieter Haas

2008-01-01

374

Exclusion of Copper from Altered Hepatocytes in White Perch (Morone americana) with Hepatic Copper Storage  

Microsoft Academic Search

Iron is excluded from foci of he- patocellular alteration in carcinogenesis of ro- dents and some fish. Among white perch (Mo- rone americana ), there is a condition of hepatic copper storage in which copper-loaded livers are produced naturally. In a group of fish col- lected from the Chesapeake Bay, Maryland (USA), from September to December 1990, we observed hepatic

Tracie E. Bunton

375

Copper alloy having improved stress relaxation resistance  

US Patent & Trademark Office Database

A copper alloy having improved stress relaxation resistance is formed from a copper base alloy that consists, by weight, essentially of 1.8%-3.0% iron, 0.01%-1.0% zinc, 0.001 %-0.25% phosphorus, 0.1 %-0.35% magnesium and the balance is copper and unavoidable impurities. When compared to other copper base alloys that include iron, zinc and phosphorous, the disclosed alloy has improved resistance to stress relaxation. In addition, directionality of stress relaxation resistance (where stress relaxation resistance is typically poorer in a transverse strip direction relative to a longitudinal strip direction for a copper alloy that is strengthened by cold rolling) is reduced to being nearly equivalent, regardless of strip direction. The alloy is particularly useful for electronic applications, such as being formed into an electrical connectors.

2003-10-14

376

Synthesis of thin films of barium titanate and barium strontium titanate nanotubes on titanium substrates  

Microsoft Academic Search

In this study, well-ordered nanotubes of titania were fabricated by anodic oxidation of pure titanium foils in HF aqueous solution. Fe-SEM images indicate the average nanotubes diameter is ?100 nm with a thickness of about 200 nm. Nanotube arrays of barium titanate and barium strontium titanate were synthesized under hydrothermal condition at 200 °C taking above-oxidized titania nanotubes as templates.

Jianling Zhao; Xiaohui Wang; Renzheng Chen; Longtu Li

2005-01-01

377

Electric Tuning of Ferromagnetic Resonances in Hexagonal-Barium-Ferrite\\/Barium-Strontium-Titanate Heterostructures  

Microsoft Academic Search

This letter reports the first demonstration of a monolithic heterostructure with a large electric tuning of the ferromagnetic resonance (FMR) at millimeter-wave frequencies. The structure is composed of a barium-strontium-titanate (BST) film and two thin platinum electrodes, all grown on a barium ferrite slab with in-plane uniaxial anisotropy. The electric tuning of the FMR responses around 60 GHz was obtained

Young-Yeal Song; Jaydip Das; Pavol Krivosik; Hyung-Kee Seo; Mingzhong Wu

2010-01-01

378

Microstructure and magnetism in barium strontium titanate (BSTO)–barium hexaferrite (BaM) multilayers  

Microsoft Academic Search

High quality multilayers of barium ferrite (BaM) and barium strontium titanate (BSTO) were grown in optimized conditions on thermally oxidized Si(100) and Al2O3 substrates using magnetron sputtering. As-grown films were amorphous and different annealing procedures were explored to stabilize crystalline phases. BSTO and BaM phases were identified using X-ray diffraction and cross-sectional scanning electron micrographs showed sharp interfaces between BSTO

N. A. Frey; R. Heindl; S. Srinath; H. Srikanth; Nancy J Dudney

2005-01-01

379

Sputtered barium titanate and barium strontium titanate films for capacitor applications  

Microsoft Academic Search

Thin barium titanate and barium strontium titanate films are being developed as dielectric film for use in dc-dc converters. Thin BaTiO3 (BT) and (BaSr)TiO3 (BST) film capacitor devices were fabricated using RF magnetron sputtering techniques. The typical dielectric constant of these film capacitors was in the range of 300 to 690. These film capacitors had dissipation factors between 0.2% to

Bang-Hung Tsao; Susan Heidger; Joseph A. Weimer

2000-01-01

380

Mass-spectrometric multielement analysis of copper and copper-base alloys, with electrical detection.  

PubMed

Relative sensitivity coefficients have been determined for 21 elements in copper and its alloys, with iron as an internal standard, by spark-source mass-spectrometry with electrical detection and magnetic peak-switching. Twenty calibration standards ranging from pure copper to 60%-copper alloys were used. The sensitivity coefficients measured appear to be independent of the elemental concentration and are obtained with a mean precision of 15%. PMID:18962160

Van Hoye, E; Gijbels, R; Adams, F

1977-10-01

381

Direct Production of Copper  

NASA Astrophysics Data System (ADS)

The use of commercially pure oxygen in flash smelting a typical chalcopyrite concentrate or a low grade comminuted matte directly to copper produces a large excess of heat. The heat balance is controlled by adjusting the calorific value of the solid feed. A portion of the sulfide material is roasted to produce a calcine which is blended with unroasted material, and the blend is then autogeneously smelted with oxygen and flux directly to copper. Either iron silicate or iron calcareous slags are produced, both being subject to a slag cleaning treatment. Practically all of the sulfur is contained in a continuous stream of SO2 gas, most of which is strong enough for liquefaction. A particularly attractive feature of these technologies is that no radically new metallurgical equipment needs to be developed. The oxygen smelting can be carried out not only in the Inco type flash furnace but in other suitable smelters such as cyclone furnaces. Another major advantage stems from abolishion of the ever-troublesome converter aisle, which is replaced with continuous roasting of a fraction of the copper sulfide feed.

Victorovich, G. S.; Bell, M. C.; Diaz, C. M.; Bell, J. A. E.

1987-09-01

382

Iron, copper, zinc, and manganese transport and regulation in pathogenic Enterobacteria: correlations between strains, site of infection and the relative importance of the different metal transport systems for virulence.  

PubMed

For all microorganisms, acquisition of metal ions is essential for survival in the environment or in their infected host. Metal ions are required in many biological processes as components of metalloproteins and serve as cofactors or structural elements for enzymes. However, it is critical for bacteria to ensure that metal uptake and availability is in accordance with physiological needs, as an imbalance in bacterial metal homeostasis is deleterious. Indeed, host defense strategies against infection either consist of metal starvation by sequestration or toxicity by the highly concentrated release of metals. To overcome these host strategies, bacteria employ a variety of metal uptake and export systems and finely regulate metal homeostasis by numerous transcriptional regulators, allowing them to adapt to changing environmental conditions. As a consequence, iron, zinc, manganese, and copper uptake systems significantly contribute to the virulence of many pathogenic bacteria. However, during the course of our experiments on the role of iron and manganese transporters in extraintestinal Escherichia coli (ExPEC) virulence, we observed that depending on the strain tested, the importance of tested systems in virulence may be different. This could be due to the different set of systems present in these strains, but literature also suggests that as each pathogen must adapt to the particular microenvironment of its site of infection, the role of each acquisition system in virulence can differ from a particular strain to another. In this review, we present the systems involved in metal transport by Enterobacteria and the main regulators responsible for their controlled expression. We also discuss the relative role of these systems depending on the pathogen and the tissues they infect. PMID:24367764

Porcheron, Gaëlle; Garénaux, Amélie; Proulx, Julie; Sabri, Mourad; Dozois, Charles M

2013-01-01

383

Iron, copper, zinc, and manganese transport and regulation in pathogenic Enterobacteria: correlations between strains, site of infection and the relative importance of the different metal transport systems for virulence  

PubMed Central

For all microorganisms, acquisition of metal ions is essential for survival in the environment or in their infected host. Metal ions are required in many biological processes as components of metalloproteins and serve as cofactors or structural elements for enzymes. However, it is critical for bacteria to ensure that metal uptake and availability is in accordance with physiological needs, as an imbalance in bacterial metal homeostasis is deleterious. Indeed, host defense strategies against infection either consist of metal starvation by sequestration or toxicity by the highly concentrated release of metals. To overcome these host strategies, bacteria employ a variety of metal uptake and export systems and finely regulate metal homeostasis by numerous transcriptional regulators, allowing them to adapt to changing environmental conditions. As a consequence, iron, zinc, manganese, and copper uptake systems significantly contribute to the virulence of many pathogenic bacteria. However, during the course of our experiments on the role of iron and manganese transporters in extraintestinal Escherichia coli (ExPEC) virulence, we observed that depending on the strain tested, the importance of tested systems in virulence may be different. This could be due to the different set of systems present in these strains, but literature also suggests that as each pathogen must adapt to the particular microenvironment of its site of infection, the role of each acquisition system in virulence can differ from a particular strain to another. In this review, we present the systems involved in metal transport by Enterobacteria and the main regulators responsible for their controlled expression. We also discuss the relative role of these systems depending on the pathogen and the tissues they infect.

Porcheron, Gaelle; Garenaux, Amelie; Proulx, Julie; Sabri, Mourad; Dozois, Charles M.

2013-01-01

384

Highly aluminium doped barium and strontium ferrite nanoparticles prepared by citrate auto-combustion synthesis  

SciTech Connect

Aluminium doped barium and strontium hexaferrite nanoparticles BaAl {sub x}Fe{sub (12-x)}O{sub 19} and SrAl {sub x}Fe{sub (12-x)}O{sub 19} were synthesised via a sol-gel route using citric acid to complex the ions followed by an auto-combustion reaction. This method shows promise for the synthesis of complex ferrite powders with small particle size. It was found that around half of the iron could be substituted for aluminium in the barium ferrite with structure retention, whereas strontium aluminium ferrites could be produced with any aluminium content including total substitution of the iron. All synthesised materials consisted of particles smaller than 1 {mu}m, which is the size of a single magnetic domain, and various doping levels were achieved with the final elemental composition being within the bounds of experimental error. The materials show structural and morphological changes as they move from iron to aluminium ferrites. Such materials may be promising for imaging applications.

Shirtcliffe, Neil J. [Nottingham Trent University, Clifton Lane, Clifton, Nottingham NG11 8NS (United Kingdom)]. E-mail: neil.shirtcliffe@ntu.ac.uk; Thompson, Simon [Nottingham Trent University, Clifton Lane, Clifton, Nottingham NG11 8NS (United Kingdom); O'Keefe, Eoin S. [QinetiQ, Farnborough, Hampshire (United Kingdom); Appleton, Steve [QinetiQ, Farnborough, Hampshire (United Kingdom); Perry, Carole C. [Nottingham Trent University, Clifton Lane, Clifton, Nottingham NG11 8NS (United Kingdom)]. E-mail: carole.perry@ntu.ac.uk

2007-02-15

385

Low Temperature Thermal Expansion of Barium Ferrite.  

National Technical Information Service (NTIS)

The linear thermal expansion of polycrystalline barium ferrite, BaFe12O19, was measured from 76 to 293 K both parallel and perpendicular to the magnetization direction. An anisotropy of about 15-20% was observed. The results match well the available data ...

A. F. Clark W. M. Haynes V. A. Deason R. J. Trapani

1975-01-01

386

STABILIZED BARIUM TITANATE CERAMICS FOR CAPACITOR DIELECTRICS  

Microsoft Academic Search

The effects of additions of LaâOâ and LaâOâ--; 3TiOâ on the electronic properties of barium titanate were investigated. ; It was found that small additions of the components markedly increase the ; lifetime of the material subjected to d-c fields of 50 v per mil at 200 l ; C. (auth);

J. B. MacChesney; P. K. Gallagher; F. V. DiMarcello

1963-01-01

387

Beta-Barium Borate Optical Parametric Oscillator.  

National Technical Information Service (NTIS)

A Beta-Barium Borate Optical Parametric Oscillator (BBO OPO) has been constructed and shipped to the Army laboratory at White Sands. This OPO is a truly continuously tunable source with a very large spectral coverage. It is pumped at the third harmonic of...

C. L. Tang

1991-01-01

388

Synthesis and Single-crystal Structures of Two Copper(II) Complexes and One Iron(II) Complex Prepared by in situ Ligand Substitution at Room Temperature  

Microsoft Academic Search

Two hexa-coordinate copper(II) complexes formulated as [Cu(phen)(4-dmampy)2(ClO4)2] and [Cu(bpy)(3-ampy)2(ClO4)2] 0.5CH3OH 0.5H2O (phen = 1,10–phenanthroline bpy = 2,2?-bipyridine, 3-ampy = 3-aminopyridine, 4-dmampy = 4-dimethylaminopyridine), and one\\u000a low-spin ferrous complex formulated as [Fe(dmbpy)3](ClO4)2 H2O (dmbpy = 4,4?-dimethyl-2,2?-bipyridine), were synthesized by in situ ligand substitution at room temperature, and characterized by X-ray single-crystal diffraction. This is the first structural\\u000a report where either 4-dmampy

Wei Huang; Huifen Qian

2006-01-01

389

Oxidative stress induced by copper and iron complexes with 8-hydroxyquinoline derivatives causes paraptotic death of HeLa cancer cells.  

PubMed

Here, we report the antiproliferative/cytotoxic properties of 8-hydroxyquinoline (8-HQ) derivatives on HeLa cells in the presence of transition metal ions (Cu(2+), Fe(3+), Co(2+), Ni(2+)). Two series of ligands were tested, the arylvinylquinolinic L1-L8 and the arylethylenequinolinic L9-L16, which can all interact with metal ions by virtue of the N,O donor set of 8-HQ; however, only L9-L16 are flexible enough to bind the metal in a multidentate fashion, thus exploiting the additional donor functions. L1-L16 were tested for their cytotoxicity on HeLa cancer cells, both in the absence and in the presence of copper. Among them, the symmetric L14 exhibits the highest differential activity between the ligand alone (IC50 = 23.7 ?M) and its copper complex (IC50 = 1.8 ?M). This latter, besides causing a significant reduction of cell viability, is associated with a considerable accumulation of the metal inside the cells. Metal accumulation is also observed when the cells are incubated with L14 complexed with other late transition metal ions (Fe(3+), Co(2+), Ni(2+)), although the biological response of HeLa cells is different. In fact, while Ni/L14 and Co/L14 exert a cytostatic effect, both Cu/L14 and Fe/L14 trigger a caspase-independent paraptotic process, which results from the induction of a severe oxidative stress and the unfolded protein response. PMID:24592930

Barilli, Amelia; Atzeri, Corrado; Bassanetti, Irene; Ingoglia, Filippo; Dall'Asta, Valeria; Bussolati, Ovidio; Maffini, Monica; Mucchino, Claudio; Marchiò, Luciano

2014-04-01

390

Accumulation of copper and other metals by copper-resistant plant-pathogenic and saprophytic pseudomonads  

SciTech Connect

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 aluminium 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.

Cooksey, D.A.; Azad, H.R. (Univ. of California, Riverside (United States))

1992-01-01

391

Seasonal variability in cadmium, lead, copper, zinc and iron concentrations in the three major fish species, Oreochromis niloticus, Lates niloticus and Rastrineobola argentea in Winam Gulf, Lake Victoria: impact of wash-off into the lake.  

PubMed

Trace metals Cadmium (Cd), Lead (Pb), Copper (Cu), Zinc (Zn) and Iron (Fe) were analyzed in edible portions of three main finfish species namely Lates niloticus, Oreochromis niloticus and Rastrineobola argentea sampled from various beaches of Winam Gulf, Lake Victoria, Kenya, in order to determine any seasonal and site variations and the results showed significantly (p < 0.05) higher mean concentrations of Cd, Cu, Zn and Fe during the wet season compared to the dry season for all the three species indicating the impact of wash-off into the lake during the rainy periods. The overall mean concentrations of the heavy metals (in ?g/g dry weight) in all combined samples ranged from 0.17-0.40 (Cd), 0.47-2.53 (Pb), 2.13-8.74 (Cu), 28.9-409.3 (Zn) and 31.4-208.1 (Fe), respectively. It was found that consumption of Rastrineobola argentea can be a significant source of heavy metals especially Zn, to humans, compared with Lates niloticus and Oreochromis niloticus, if only the muscle parts of the latter two are consumed. PMID:22130608

Ongeri, David M K; Lalah, Joseph O; Wandiga, Shem O; Schramm, Karl-Werner; Michalke, Bernard

2012-02-01

392

Are There Any Stars Lacking Neutron-capture Elements? Evidence from Strontium and Barium  

NASA Astrophysics Data System (ADS)

The cosmic dispersion in the abundances of the heavy elements strontium and barium in halo stars is well known. Strontium and barium are detected in most cool, metal-poor giants, but are these elements always detectable? To identify stars that could be considered probable candidates for lacking these elements, I examine the stellar abundance data available in the literature for 1148 field stars and 226 stars in dwarf galaxies, 776 of which have metallicities lower than [Fe/H] <-2.0. Strontium or barium have been detected in all field, globular cluster, and dwarf galaxy environments studied. All upper limits are consistent with the lowest detected ratios of [Sr/H] and [Ba/H]. The frequent appearance of these elements raises the intriguing prospect that at least one kind of neutron-capture reaction operates as often as the nucleosynthesis mechanisms that produce lighter elements, such as magnesium, calcium, or iron, although the yields of heavy elements may be more variable.

Roederer, Ian U.

2013-01-01

393

ARE THERE ANY STARS LACKING NEUTRON-CAPTURE ELEMENTS? EVIDENCE FROM STRONTIUM AND BARIUM  

SciTech Connect

The cosmic dispersion in the abundances of the heavy elements strontium and barium in halo stars is well known. Strontium and barium are detected in most cool, metal-poor giants, but are these elements always detectable? To identify stars that could be considered probable candidates for lacking these elements, I examine the stellar abundance data available in the literature for 1148 field stars and 226 stars in dwarf galaxies, 776 of which have metallicities lower than [Fe/H] <-2.0. Strontium or barium have been detected in all field, globular cluster, and dwarf galaxy environments studied. All upper limits are consistent with the lowest detected ratios of [Sr/H] and [Ba/H]. The frequent appearance of these elements raises the intriguing prospect that at least one kind of neutron-capture reaction operates as often as the nucleosynthesis mechanisms that produce lighter elements, such as magnesium, calcium, or iron, although the yields of heavy elements may be more variable.

Roederer, Ian U., E-mail: iur@obs.carnegiescience.edu [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)

2013-01-01

394

Effect of iron-intermetallics and porosity on tensile and impact properties of aluminum-silicon-copper and aluminum-silicon-magnesium cast alloys  

NASA Astrophysics Data System (ADS)

Aluminum-silicon (Al-Si) alloys are an important class of materials that constitute the majority of aluminum cast parts produced, due to their superior properties and excellent casting characteristics. Within this family of alloys, Al-Si-Cu and Al-Si-Mg cast alloys are frequently employed in automotive applications. The commercially popular 319 and 356 alloys, representing these two alloy systems, were selected for study in the present work, with the aim of investigating the effect of iron intermetallics and porosity on the alloy performance. This was carried out through a study of the tensile and impact properties, these being two of the important mechanical properties used in design calculations. Iron, through the precipitation of second phase intermetallic constituents, in particular the platelike beta-Al5FeSi phase, is harmful to the alloy properties. Likewise, gas- or shrinkage porosity in castings is also detrimental to the mechanical properties. By determining the optimum alloying, melt processing and solidification parameters (viz., Fe content, Sr modification and cooling rate) required to minimize the harmful effects of porosity and iron intermetallics, and studying their role on the fracture behavior, the fracture mechanism in the alloys could be determined. Castings were prepared from both industrial and experimental 319.2, B319.2 and A356.2 alloy melts, containing Fe levels of 0.2--1.0 wt%. Sr-modified (˜200 ppm) melts were also prepared for each alloy Fe level. The end-chilled refractory mold used provided directional solidification and a range of cooling rates (or dendrite arm spacings, DAS) within the same casting. Tensile and impact test samples machined from specimen blanks sectioned from the castings at various heights above the chill end provided DASs of 23--85mum. All samples were T6-heat-treated before testing. Tests were carried out employing Instron Universal and Instrumented Charpy testing machines. Optical microscopy, image analysis, SEM and EPMA techniques were used for microstructural and fracture analysis. The results show that the highest cooling rate (23 mum DAS) is the most significant parameter controlling the size and distribution of the beta-Al 5FeSi phase and porosity in the unmodified 319.2 and A356.2 alloys. (Abstract shortened by UMI.)

Ma, Zheyuan

395

Elevated silver, barium and strontium in antlers, vegetation and soils sourced from CWD cluster areas: Do Ag\\/Ba\\/Sr piezoelectric crystals represent the transmissible pathogenic agent in TSEs?  

Microsoft Academic Search

High levels of Silver (Ag), Barium (Ba) and Strontium (Sr) and low levels of copper (Cu) have been measured in the antlers, soils and pastures of the deer that are thriving in the chronic wasting disease (CWD) cluster zones in North America in relation to the areas where CWD and other transmissible spongiform encephalopathies (TSEs) have not been reported. The

Mark Purdey

2004-01-01

396

Hepatic iron accumulation over time in European starlings (Sturnus vulgaris) fed two levels of iron.  

PubMed

European starlings (Sturnus vulgaris) were used as a passerine bird model to examine the effect of dietary iron on the level of hepatic iron in birds. Nestling and fledgling starlings (n = 56) were raised on a controlled-iron diet. When birds maintained constant body weight, they were assigned in pairs to cages, and baseline sampling was performed. Pairs were then assigned to one of two diets: the controlled-iron diet (168 ppm, dry basis) or a high-iron diet (3,035 ppm, dry basis). Dry-matter intake and iron consumption were recorded. Dry-matter intake did not differ between the dietary treatment groups and was stable during treatment periods. Iron intake was higher in the high-iron group (P < 0.05). Birds were euthanized at baseline, 8 wk, and 16 wk. Body, liver, and spleen weights were measured. Hepatic iron and copper concentrations were determined. Body weight did not differ between the two treatment groups or among individuals for the study duration. Liver iron concentration differed over time and between treatment groups. Birds receiving both treatments had similar liver iron content at week 8 (3,107 +/- 228.6 ppm and 3,122 +/- 306.2 ppm high and controlled iron, respectively; P > 0.05), but by week 16, birds consuming the high-iron diet had greater hepatic iron levels than those consuming the controlled-iron diet (5,929 +/- 937.2 ppm and 3,683 +/- 229.5 ppm high and controlled iron, respectively; P < 0.05). Birds on the controlled-iron diet also had higher hepatic iron at 16 wk than at 8 wk. Liver copper decreased over time in all birds regardless of treatment. Results show that both dietary iron level and duration of time influenced hepatic iron storage. The controlled-iron diets still allowed accumulation of hepatic iron in an 8-wk period. PMID:11428395

Crissey, S D; Ward, A M; Block, S E; Maslanka, M T

2000-12-01

397

Establishment of a Protocol for Determining Gastrointestinal Transit Time in Mice Using Barium and Radiopaque Markers  

PubMed Central

Objective The purpose of this study was to establish a minimally invasive and reproducible protocol for estimating the gastrointestinal (GI) transit time in mice using barium and radiopaque markers. Materials and Methods Twenty 5- to 6-week-old Balb/C female mice weighing 19-21 g were used. The animals were divided into three groups: two groups that received loperamide and a control group. The control group (n = 10) animals were administered physiological saline (1.5 mL/kg) orally. The loperamide group I (n = 10) and group II (n = 10) animals were administered 5 mg/kg and 10 mg/kg loperamide orally, respectively. Thirty minutes after receiving the saline or loperamide, the mice was administered 80 µL of barium solution and six iron balls (0.5 mm) via the mouth and the upper esophagus by gavage, respectively. Afterwards, the mice were continuously monitored with fluoroscopic imaging in order to evaluate the swallowing of the barium solution and markers. Serial fluoroscopic images were obtained at 5- or 10-min intervals until all markers had been excreted from the anal canal. For analysis, the GI transit times were subdivided into intestinal transit times (ITTs) and colon transit times (CTTs). Results The mean ITT was significantly longer in the loperamide groups than in the control group (p < 0.05). The mean ITT in loperamide group II (174.5 ± 32.3) was significantly longer than in loperamide group I (133.2 ± 24.2 minute) (p < 0.05). The mean CTT was significantly longer in loperamide group II than in the control group (p < 0.05). Also, no animal succumbed to death after the experimental procedure. Conclusion The protocol for our study using radiopaque markers and barium is reproducible and minimally invasive in determining the GI transit time of the mouse model.

Myagmarjalbuu, Bolormaa; Moon, Myeong Ju; Heo, Suk Hee; Jeong, Seo In; Park, Jong-Seong; Jun, Jae Yeoul; Kang, Heoung Keun

2013-01-01

398

Corrosion resistant gray cast iron graphite flake alloys  

SciTech Connect

Corrosion resistant gray cast iron alloys useful in downhole oil well environments and the like. The alloys are substantially lower in cost and substantially higher in tensile strength than high nickel-copper cast irons commonly used downhole in submergible pumps. The alloys contain substantial amounts of aluminum in combination with nickel, chromium, manganese, molybdenum, carbon, silicon, and iron. Copper, tin, vanadium, and boron may also be included. Both hardenable and non-hardenable alloys are provided.

Betts, B. A.

1985-10-22

399

Barium uptake and adsorption in diatoms  

Microsoft Academic Search

Using trace metal-defined culture conditions, we measured the cellular barium concentration in cultures of the diatom Thalassiosira weissflogii. In cultures with low Fe concentration, at a typical surface seawater Ba concentration of 35 to 40 nmol\\/L, the cellular Ba was 0.5 ?mol\\/mol P (?0.04 ?g\\/g dw), much below all previously published values for phytoplankton. When the Fe concentration in the

Erika Sternberg; Degui Tang; Tung-Yuan Ho; Catherine Jeandel; François M. M. Morel

2005-01-01

400

Leachability of barium-radium sulphate sludges  

Microsoft Academic Search

This paper presents results from the first phase of a research program designed to examine the leachability of radium-226 from barium-radium sulphate sludges. Batch leaching tests were performed. Results showed that liquid:solid contact time was relatively unimportant; radium in the sludge was stable in the presence of deionized water with a slight increase in the amount leached per gram of

P. M. Huck; B. Anderson

1982-01-01

401

Formation of barium-tantalum oxynitrides  

Microsoft Academic Search

Oxynitride powders suitable for sintering to form dielectric ABO3-type perovskites have been prepared by nitriding barium carbonate and tantalum oxide. Both heat treatment in air and reaction in flowing ammonia yield isostructural oxynitride phases, but the amount and electronic state of the oxynitrides depend on the nitriding gas conditions. A red-brown oxynitride of high nitrogen content is described as Ba2Ta2O3N2

A. Hellwig; A. Hendry

1994-01-01

402

Rapid barium removal in the Delaware estuary  

SciTech Connect

Six profiles of dissolved barium covering the entire salinity range of the Delaware River and Bay estuary from March through September 1996 were collected and analyzed. The profiles are similar to one another in both shape and magnitude except for one attribute. A sudden ({le} 24 days), nearly complete (>90%) removal of dissolved Ba in midestuary occurs in mid-May followed by an 80% recovery in early June. This removal appears to be temporally and spatially coupled to the end of the spring bloom. Based on such episodic behavior, and on recent work with flocculation of diatom exudates, the authors conclude that the Ba depletion is caused by barite precipitation in the estuary during the late stages of the bloom. This would imply that lower estuary and inner coastal margin sediments associated with eutrophic estuaries receive a seasonal pulse of barite. The suddenness of this event also implies that sedimentary barite is strongly influenced by high productivity events. Comparison of the riverine Ba concentration with the effective riverine end member after desorptive barium release yields an estimated 30--40 nM Ba available from the suspended sediments as they enter the estuary. This estimate is supported by excess barium in unfiltered samples over filtered samples taken from the river and also by calculations done elsewhere.

Stecher, H.A. III [Univ. of Delaware, Lewes, DE (United States). College of Marine Studies] [Univ. of Delaware, Lewes, DE (United States). College of Marine Studies; [Univ. of Delaware, Newark, DE (United States). Dept. of Geology; Kogut, M.B. [Univ. of Washington, Seattle, WA (United States). School of Oceanography] [Univ. of Washington, Seattle, WA (United States). School of Oceanography

1999-04-01

403

Mechanisms of copper incorporation into human ceruloplasmin.  

PubMed

Ceruloplasmin is a multicopper oxidase essential for normal iron homeostasis. To elucidate the mechanisms of copper incorporation into this protein, holoceruloplasmin biosynthesis was examined by immunoblot analysis and (64)Cu metabolic labeling of Chinese hamster ovary cells transfected with cDNAs encoding wild-type or mutant ceruloplasmin. This analysis reveals that the incorporation of copper into newly synthesized apoceruloplasmin in vivo results in a detectable conformational change in the protein. Strikingly, despite the unique functional role of each copper site within ceruloplasmin, metabolic studies indicate that achieving this final conformation-driven state requires the occupation of all six copper-binding sites with no apparent hierarchy for copper incorporation at any given site. Consistent with these findings a missense mutation (G631R), resulting in aceruloplasminemia and predicted to alter the interactions at a single type I copper-binding site, results in the synthesis and secretion only of apoceruloplasmin. Analysis of copper incorporation into apoceruloplasmin in vitro reveals that this process is cooperative and that the failure of copper incorporation into copper-binding site mutants observed in vivo is intrinsic to the mutant proteins. These findings reveal a precise and sensitive mechanism for the formation of holoceruloplasmin under the limiting conditions of copper availability within the cell that may be generally applicable to the biosynthesis of cuproproteins within the secretory pathway. PMID:12351628

Hellman, Nathan E; Kono, Satoshi; Mancini, Grazia M; Hoogeboom, A J; De Jong, G J; Gitlin, Jonathan D

2002-11-29

404

Effect of 3d-transition metal doping on the shielding behavior of barium borate glasses: A spectroscopic study.  

PubMed

UV-visible and FT infrared spectra were measured for prepared samples before and after gamma irradiation. Base undoped barium borate glass of the basic composition (BaO 40%-B2O3 60mol.%) reveals strong charge transfer UV absorption bands which are related to unavoidable trace iron impurities (Fe(3+)) within the chemical raw materials. 3d transition metal (TM)-doped glasses exhibit extra characteristic absorption bands due to each TM in its specific valence or coordinate state. The optical spectra show that TM ions favor generally the presence in the high valence or tetrahedral coordination state in barium borate host glass. Infrared absorption bands of all prepared glasses reveal the appearance of both triangular BO3 units and tetrahedral BO4 units within their characteristic vibrational modes and the TM-ions cause minor effects because of the low doping level introduced (0.2%). Gamma irradiation of the undoped barium borate glass increases the intensity of the UV absorption together with the generation of an induced broad visible band at about 580nm. These changes are correlated with suggested photochemical reactions of trace iron impurities together with the generation of positive hole center (BHC or OHC) within the visible region through generated electrons and positive holes during the irradiation process. PMID:24983922

ElBatal, H A; Abdelghany, A M; Ghoneim, N A; ElBatal, F H

2014-12-10

405

Occupational genotoxicity among copper smelters.  

PubMed

Occupational exposure in a copper smelting industry may produce various adverse health effects including cancer. Despite a number of well-documented studies reporting an increased risk of cancer among copper smelter workers, the data on genotoxic effects in this industry are scarce. In view of the above, an assessment of DNA damage in peripheral blood leukocytes by Comet assay from copper smelter workers was undertaken. Additionally, the proton-induced X-ray emission (PIXE) analysis was assessed to determine the metal content of samples. The study was conducted with all workers from a copper smelter (males; n = 11), and a control group (n = 11) was recruited. The results of our study showed a significant increase (p < 0.001; Mann-Whitney test) in DNA damage in peripheral blood lymphocytes of smelter workers, compared to the controls (p < 0.001; Mann-Whitney test). No correlation between DNA damage or metal concentration and age mean or time of exposure was found under study. Our findings indicate that copper smelter workers have increased levels of DNA damage in somatic cells, suggesting a potential health risk for the workers. PIXE results show the presence of copper, iron, and other metals. PMID:22042770

De Olivera, Juliana Viégas Duarte; Boufleur, Liana Appel; Dos Santos, Carla Eliete Iochims; Dias, Johnny Ferraz; Squeff, Cíntia Haag; Silva, Guilherme Ruivo Gonçalves; Ianistcki, Martus; Benvegnú, Vinícius Cosmos; Da Silva, Juliana

2012-10-01

406

Copper staves in the blast furnace  

SciTech Connect

Operational data for stave cooling systems for two German blast furnaces show good correlation with predicted thermal results. Copper staves have been installed in blast furnaces in the zones exposed to the highest thermal loads. The good operational results achieved confirm the choice of copper staves in the areas of maximum heat load. Both temperature measurements and predictions establish that the MAN GHH copper staves do not experience large temperature fluctuations and that the hot face temperatures will be below 250 F. This suggests that the copper staves maintain a more stable accretion layer than the cast iron staves. Contrary to initial expectations, heat flux to the copper staves is 50% lower than that to cast iron staves. The more stable accretion layer acts as an excellent insulator for the stave and greatly reduces the number of times the hot face of the stave is exposed to the blast furnace process and should result in a more stable furnace operation. In the future, it may be unnecessary to use high quality, expensive refractories in front of copper staves because of the highly stable accretion layer that appears to rapidly form due to the lower operating temperature of the staves. There is a balance of application regions for cast iron and copper staves that minimizes the capital cost of a blast furnace reline and provides an integrated cooling system with multiple campaign life potential. Cast iron staves are proven cooling elements that are capable of multiple campaign life in areas of the blast furnace which do not experience extreme heat loads. Copper staves are proving to be an effective and reliable blast furnace cooling element that are subject to virtually no wear and are projected to have a longer campaign service life in the areas of highest thermal load in the blast furnace.

Helenbrook, R.G. [ATSI, Inc., Amherst, NY (United States); Kowalski, W. [Thyssen Stahl AG, Duisburg (Germany); Grosspietsch, K.H. [Preussag Stahl AG, Saltzgitter (Germany); Hille, H. [MAN GHH AG, Oberhausen (Germany)

1996-08-01

407

Binding and Leakage of Barium in Alginate Microbeads  

PubMed Central

Microbeads of alginate cross-linked with Ca2+ and/or Ba2+ are popular matrices in cell-based therapy. The aim of this study was to quantify the binding of barium in alginate microbeads and its leakage under in vitro and accumulation under in vivo conditions. Low concentrations of barium (1 mM) in combination with calcium (50 mM) and high concentrations of barium (20 mM) in gelling solutions were used for preparation of microbeads made of high-G and high-M alginates. High-G microbeads accumulated barium from gelling solution and contained higher concentrations of divalent ions for both low- and high-Ba exposure compared to high-G microbeads exposed to calcium solely and to high-M microbeads for all gelling conditions. Although most of the unbound divalent ions were removed during the wash and culture steps, leakage of barium was still detected during storage. Barium accumulation in blood and femur bone of mice implanted with high-G beads was found to be dose-dependent. Estimated barium leakage relevant to transplantation to diabetic patients with islets in alginate microbeads showed that the leakage was 2.5 times lower than the tolerable intake value given by WHO for high-G microbeads made using low barium concentration. The similar estimate gave 1.5 times higher than is the tolerable intake value for the high-G microbeads made using high barium concentration. In order to reduce the risk of barium accumulation that may be of safety concern, the microbeads made of high-G alginate gelled with a combination of calcium and low concentration of barium ions is recommended for islet transplantation.

M?rch, Yrr A.; Qi, Meirigeng; Gundersen, Per Ole M.; Formo, Kjetil; Lacik, Igor; Skjak-Braek, Gudmund; Oberholzer, Jose; Strand, Berit L.

2013-01-01

408

Processing of copper converter slag for metal reclamation. Part I: Extraction and recovery of copper and cobalt.  

PubMed

Clean processing of copper converter slag to reclaim cobalt and copper could be a challenge. An innovative and environmentally sound approach for recovering valuable metals from such a slag has been developed in the present study. Curing the slag with strong sulphuric acid, without re-smelting or roasting as practiced currently in the industry, render it accessible to leaching, and more than 95% of cobalt and up to 90% of copper was extracted together with iron by water leaching, leaving silica behind in a residue. The copper in the leach liquor was recovered by cementation with iron and the dissolved iron crystallized as ferrous sulphate monohydrate. The cobalt in the mother-liquor rich in iron was recovered by either cementation or sulphide precipitation. Operation variables in the new process were also investigated and optimized. PMID:17985669

Deng, Tong; Ling, Yunhan

2007-10-01

409

High toughness-high strength iron alloy  

NASA Technical Reports Server (NTRS)

An iron alloy is provided which exhibits strength and toughness characteristics at cryogenic temperatures. The alloy consists essentially of about 10 to 16 percent by weight nickel, about 0.1 to 1.0 percent by weight aluminum, and 0 to about 3 percent by weight copper, with the balance being essentially iron. The iron alloy is produced by a process which includes cold rolling at room temperature and subsequent heat treatment.

Stephens, J. R.; Witzke, W. R. (inventors)

1980-01-01

410

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.

Chaturvedi, Kaveri S.; Henderson, Jeffrey P.

2014-01-01

411

Mechanisms of Copper Ion Mediated Huntington's Disease Progression  

Microsoft Academic Search

Huntington's disease (HD) is caused by a dominant polyglutamine expansion within the N-terminus of huntingtin protein and results in oxidative stress, energetic insufficiency and striatal degeneration. Copper and iron are increased in the striata of HD patients, but the role of these metals in HD pathogenesis is unknown. We found, using inductively-coupled-plasma mass spectroscopy, that elevations of copper and iron

Jonathan H. Fox; Jibrin A. Kama; Gregory Lieberman; Raman Chopra; Kate Dorsey; Vanita Chopra; Irene Volitakis; Robert A. Cherny; Ashley I. Bush; Steven Hersch; Katrina Gwinn-Hardy

2007-01-01

412

Barium and europium abundances in cool dwarf stars and nucleosynthesis of heavy elements  

NASA Astrophysics Data System (ADS)

We revise barium abundances in 29 cool stars with metallicities [Fe/H] ranging from -2.20 to 0.07 and europium abundances in 15 stars with [Fe/H] from -1.52 to 0.07. The sample has been extracted from Fuhrmann's lists (\\cite{Fuhr3, Fuhr4}) and confined to main-sequence and turnoff stars with only one subgiant added. The results are based on differential NLTE model atmosphere analyses of spectra that have a typical S/N of 200 and a resolution of 40000 or 60000. The statistical equilibrium of Eu Ii is first investigated with a model atom containing 32 levels of Eu Ii plus the ground state of Eu Iii. NLTE effects decrease the equivalent widths of the Eu Ii lines compared with LTE resulting in positive NLTE abundance corrections which are below 0.08 dex for all the stars investigated. The solar barium abundance eps {Ba,sun} = 2.21 and the europium abundance eps {Eu,sun} = 0.53 are found from the Ba Ii and Eu Ii solar flux line profile fitting, and they coincide within error bars with meteoritic abundances of Grevesse et al. (\\cite{met96}). Here the usual scale with eps {H} = 12 is used. The isotopic ratio \\iso{151}{Eu}: \\iso{153}{Eu} = 55: 45 is obtained from solar disk center intensity profile fitting of the Eu Ii lambda 4129 Åline. We report here for the first time that the elemental ratios [Ba/Fe], [Eu/Fe] and [Eu/Ba] show a different behaviour for stars of different Galactic populations. For the halo stars the [Ba/Fe] ratios are approximately solar, europium is overabundant relative to iron and barium with the mean values [Eu/Fe] = 0.62 and [Eu/Ba] = 0.64. For thick disk stars it is found that a) barium is slightly underabundant relative to iron by about 0.1 dex; b) europium is overabundant relative to iron with the [Eu/Fe] ratios between 0.30 and 0.44; and c) europium is overabundant relative to barium with a mean value of [Eu/Ba] = 0.49 +/- 0.03. A step-like change in the [Eu/Ba] and [Ba/Fe] ratios occurs at the thick to thin disk transition; so, nearly solar elemental ratios [Ba/Fe], [Eu/Fe] and [Eu/Ba] are found for the thin disk stars. These data suggest that a) the halo and thick disk stellar population formed quickly during an interval comparable with the evolution time of an AGB progenitor of 3 to 4 M_sun, and the r-process dominated heavy element production at that epoch; b) there was a hiatus in star formation before the early stage of the thin disk developed. The even-to-odd Ba isotope ratios estimated from hyperfine structure (HFS) affecting the Ba Ii resonance line in the halo and thick disk stars favour a significant contribution of \\iso{138}{Ba} to barium for a pure r-process, and this is supported by the recent data of Arlandini et al. (\\cite{rs99}). Based on observations at the German Spanish Astronomical Center, Calar Alto, Spain

Mashonkina, L.; Gehren, T.

2000-12-01

413

The siderophore yersiniabactin binds copper to protect pathogens during infection  

PubMed Central

Bacterial pathogens secrete chemically diverse iron chelators called siderophores, which may exert additional distinctive functions in vivo. Among these, uropathogenic E.coli often co-express the virulence-associated siderophore yersiniabactin (Ybt) along with catecholate siderophores. Here we used a novel mass-spectrometric screening approach to reveal that yersiniabactin is also a physiologically favorable copper (II) ligand. Direct mass-spectrometric detection of the resulting Cu(II)-Ybt complex in mice and humans with E. coli urinary tract infections demonstrates copper binding to be a physiologically relevant in vivo interaction during infection. Yersiniabactin expression corresponded to higher copper resistance among human urinary tract isolates, suggesting a protective role for this interaction. Chemical and genetic characterization showed that yersiniabactin helps bacteria resist copper toxicity by sequestering host-derived copper (II) and preventing its catechol-mediated reduction to copper (I). Together, these studies reveal a new virulence-associated function for yersiniabactin that is distinct from iron binding.

Chaturvedi, Kaveri S.; Hung, Chia S.; Crowley, Jan R.; Stapleton, Ann E.; Henderson, Jeffrey P.

2013-01-01

414

BARIUM IN TEETH AS INDICATOR OF BODY BURDEN  

EPA Science Inventory

A study was conducted to determine the biological availability of naturally occurring barium in a municipal drinking water by the analysis of barium in deciduous teeth of children. The grade school children of two Illinois towns were chosen for the study. The towns were chosen ba...

415

Toward a more environmentally benign synthesis of doped barium titanate  

Microsoft Academic Search

Barium titanate is one of the most thoroughly studied members of the perovskite family due to its prominent place in the electroceramic industry. To be used as a capacitor at room temperature, a high-dielectric constant is needed which is achieved through doping. The focus of this research was to develop a more environmentally benign alternative to the doping of barium

Anne Marteel-Parrish; Samantha DeCarlo; Danielle Harlan; Jonathan Martin; Heather Sheridan

2008-01-01

416

Large electrostrictive actuation of barium titanate single crystals  

Microsoft Academic Search

An experimental investigation of the electromechanical behavior of single crystals of the ferroelectric perovskite barium titanate is presented. An experimental setup has been designed to investigate large strain actuation in single crystal ferroelectrics subjected to combined electrical and mechanical loading. Experiments have been performed on initially single domain crystals of barium titanate with (100) and (001) orientation at compressive stresses

E. Burcsu; G. Ravichandran; K. Bhattacharya

2004-01-01

417

Composition and structure measurements in an ionospheric barium cloud  

NASA Astrophysics Data System (ADS)

A 48 kg barium payload was launched from Eglin Air Force Base, Florida on 12 December 1980 at 2311 GMT and detonated at 183.7 km. At 2342:50.25 GMT, a second rocket, instrumented with an ion mass spectrometer and pulsed plasma probes, was fired to traverse the barium cloud. Composition, ion density, and structure measurements were acquired up to 241.2 km in both the natural and disturbed ionosphere. The rocket penetrated the barium cloud between 147 and 184 km. In addition to the Ba+, Ba++ produced by H Lyman alpha ionization, and Ca+, an impurity in the barium were detected in the cloud. A peak barium ion concentration of about 6,000,000 ions cu cm was measured at 161 km where the ionospheric NO+ and O2+ ions were essentially eliminated by large recombination loss. The bottom side of the barium cloud had a relatively smooth structure while the top side showed significant density fluctuations. The first experimental evidence of a theoretically predicted E region 'image cloud' was found in the form of an enhanced NO+ layer just below the barium cloud. Unexplained wave-like density variations in O+, NO+, and O2(+) also were seen above the barium cloud to 195 km. A quantitative estimate of the outgassing water vapor concentrations near the payload's surface was made using the fast change transfer rate coefficient for O+ + H2O yields H2O+ + O that created the observed water vapor ions.

Narcisi, R.; Tracinski, E.; Federico, G.; Wlodyka, L.; Bench, P.

1981-12-01

418

Removal of barium and radium from groundwater. Environmental research brief  

Microsoft Academic Search

A research project was undertaken to investigate processes for removing barium and radium from drinking water. Special emphasis was placed on ion exchange processes that can be used without adding large concentrations of sodium to the water. The wastes from radium and barium removal processes were also characterized, and processes suitable for treatment of ion-exchange brines were evaluated. The report

V. L. Snoeyink; C. C. Chambers; C. K. Schmidt; R. F. Manner; A. G. Myers

1987-01-01

419

Barium strontium titanate powder obtained by polymeric precursor method  

Microsoft Academic Search

Pure barium strontium titanate powder, with Ba\\/Sr ratio of 80\\/20 was prepared by the polymeric precursor method (also called Pechini process). The powder was obtained after a calcination at 800 °C for 8 h and characterized by XRD, IR, BET and SEM. The requirements to avoid barium carbonate as a secondary phase are presented and discussed in detail.

A. Ries; A. Z. Simões; M. Cilense; M. A. Zaghete; J. A. Varela

2003-01-01

420

Barium strontium titanate powder obtained by polymeric precursor method  

SciTech Connect

Pure barium strontium titanate powder, with Ba/Sr ratio of 80/20 was prepared by the polymeric precursor method (also called Pechini process). The powder was obtained after a calcination at 800 deg. C for 8 h and characterized by XRD, IR, BET and SEM. The requirements to avoid barium carbonate as a secondary phase are presented and discussed in detail.

Ries, A.; Simoes, A.Z.; Cilense, M.; Zaghete, M.A.; Varela, J.A

2003-03-15