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1

Molecular Mediators Governing Iron-Copper Interactions  

PubMed Central

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

Gulec, Sukru; Collins, James F.

2015-01-01

2

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

E-print Network

with iron oxide and barium titanate nanoparticles Z. Guo a,*, S.-E. Lee a , H. Kim a , S. Park a , H.T. Hahn (PU) nanocomposites reinforced with magnetic iron oxide nanoparticles and/or dielectric barium the introduction of the dielectric barium titanate nanoparticle into Fe2O3/PU nanocomposites. The permeability

Guo, John Zhanhu

3

Electrolytic Corrosion of Iron and Copper  

Microsoft Academic Search

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

W. F. Higgins

1954-01-01

4

Reduction behavior of barium hexaferrite into metallic iron nanocrystallites  

NASA Astrophysics Data System (ADS)

Barium hexaferrite (BaFe 12O 19) powder was prepared through the ceramic route by calcination of a stoichiometric mixture of barium carbonate and iron oxide at 1200 °C for 2 h. Compacts of synthesized BaFe 12O 19 powder were isothermally reduced in hydrogen atmosphere at 600-1000 °C. Based on thermogravimetric analysis, the reduction behavior of BaFe 12O 19 and reaction kinetics and mechanism were studied. The initial ferrite powder and the various reduction products were characterized by X-ray diffraction analysis,a scanning electron microscope and a vibrating sample magnetometer to reveal the effect of hydrogen reduction on composition, microstructure and magnetic properties. The reduction rate was found to be controlled by interfacial chemical reaction mechanism. Metallic iron was formed in nanosized regimes while grain growth and coalescence were observed at higher reduction temperatures. Magnetic measurements show diluted magnetic properties for the formed metallic iron, whereas coercivity values were in the range 14.1-55 Oe and saturation magnetization varied from 24.79 to 36.15 emu/g. These values have been ascribed to the formation and growth of nanosized metallic iron particles as the reduction treatment proceeded.

Bahgat, M.; Radwan, M.; Hessien, M. M.

2007-03-01

5

In-situ formation of barium ferrite in iron doped "tetragonal tungsten bronze": Elaboration of room temperature multiferroic composites  

E-print Network

1 In-situ formation of barium ferrite in iron doped "tetragonal tungsten bronze": Elaboration their room temperature multiferroics properties to the occurrence of barium ferrite parasitic phases to the in-situ formation of barium ferrite is given. We show that we can control the spurious ferrite phase

Paris-Sud XI, Université de

6

Bulk diffusion of iron in copper  

NASA Astrophysics Data System (ADS)

The temperature dependence of bulk diffusion coefficient of iron in copper has been determined by electron microprobe analysis (EMA) in the temperature range from 923 to 1273 K to be D_{Fe} = 0.03 × 10^{ - 4} exp ( { - {187 kJ/mol}}/{{RT}}} ) m2/s. The results obtained differ from the parameters of bulk diffusion determined by the tracer method: the activation energy is less by 30 kJ/mol and the preexponential factor is less by approximately a factor of 50. The deviations of the solutions from the ideality does not explain the discrepancies obtained.

Prokoshkina, D. S.; Rodin, A. O.; Esin, V. A.

2012-06-01

7

Iron versus Copper II. Principles and Applications in Bioinorganic Chemistry.  

ERIC Educational Resources Information Center

Discusses the differences between iron and copper. Describes various aspects of the behaviors of these two elements, including those of biological and environmental significance. Addresses the evolution of the atmosphere and sedimentary ore formation, the phylogeny of iron and copper, and some anthropological notes regarding the use of the metals.…

Ochiai, Ei-Ichiro

1986-01-01

8

Retronasal smell and detection thresholds of iron and copper salts  

Microsoft Academic Search

Iron and copper salts, when placed in the mouth, may give rise to odorous compounds which complicate their functioning as chemical stimuli. The contribution of retronasal smell to perception of these metal salts at threshold has not been determined. Detection thresholds of the sulfate and chloride salts of ferrous iron and copper, and sodium chloride (as a control) were determined

Effie M. Epke; Harry T. Lawless

2007-01-01

9

High temperature superconducting properties: Yttrium barium copper oxides. (Latest citations from the Aerospace database). Published Search  

SciTech Connect

The bibliography contains citations concerning experimental and theoretical studies of high temperature superconducting properties of yttrium barium copper oxides (Y-Ba-Cu-O). Physical properties of superconducting materials and devices are discussed, including electrical, magnetic, structural, electronic, thermal, transport, optical, and elastic properties. Topics include Y-Ba-Cu-O ceramics, critical current density, critical current anisotropy, crystal structures, crystal growth, effects of dopants, crystal defects, structural phase transformation, oxygen stoichiometry, thermal degradation, and stability of Y-Ba-Cu-O materials in various environments. Citations concerning superconducting Y-Ba-Cu-O films are examined in a separate bibliography. (Contains 250 citations and includes a subject term index and title list.)

Not Available

1993-10-01

10

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. PMID:20233928

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

2010-01-01

11

Multi-Copper Oxidases and Human Iron Metabolism  

PubMed Central

Multi-copper oxidases (MCOs) are a small group of enzymes that oxidize their substrate with the concomitant reduction of dioxygen to two water molecules. Generally, multi-copper oxidases are promiscuous with regards to their reducing substrates and are capable of performing various functions in different species. To date, three multi-copper oxidases have been detected in humans—ceruloplasmin, hephaestin and zyklopen. Each of these enzymes has a high specificity towards iron with the resulting ferroxidase activity being associated with ferroportin, the only known iron exporter protein in humans. Ferroportin exports iron as Fe2+, but transferrin, the major iron transporter protein of blood, can bind only Fe3+ effectively. Iron oxidation in enterocytes is mediated mainly by hephaestin thus allowing dietary iron to enter the bloodstream. Zyklopen is involved in iron efflux from placental trophoblasts during iron transfer from mother to fetus. Release of iron from the liver relies on ferroportin and the ferroxidase activity of ceruloplasmin which is found in blood in a soluble form. Ceruloplasmin, hephaestin and zyklopen show distinctive expression patterns and have unique mechanisms for regulating their expression. These features of human multi-copper ferroxidases can serve as a basis for the precise control of iron efflux in different tissues. In this manuscript, we review the biochemical and biological properties of the three human MCOs and discuss their potential roles in human iron homeostasis. PMID:23807651

Vashchenko, Ganna; MacGillivray, Ross T. A.

2013-01-01

12

High temperature superconducting films: Yttrium barium copper oxides. (Latest citations from the Aerospace database). Published Search  

SciTech Connect

The bibliography contains citations concerning the development, fabrication, characterization, and patterning of high temperature superconducting films based on yttrium barium copper oxides (Y-Ba-Cu-O). Fabrication methods include magnetron sputtering, laser beam evaporation, sol-gel process, ion beam deposition, spin/on pyrolysis, ion implantation, and chemical vapor deposition. Structural, electrical, morphological, and optical properties of Y-Ba-Cu-O films grown on various substrates such as SrTiO3, ceramics, silicon, and saphire are discussed. Effects of substrates, ion irradiation, fabrication conditions, and additives on the formation and properties of Y-Ba-Cu-O films are considered. The transition temperature of this high-temperature superconducting film is between 80 and 100 degrees Kelvin. (Contains a minimum of 154 citations and includes a subject term index and title list.)

Not Available

1993-10-01

13

Transcuprein is a Macroglobulin Regulated by Copper and Iron Availability  

PubMed Central

SUMMARY Transcuprein is a high affinity copper carrier in the plasma involved in the initial distribution of copper entering the blood from the digestive tract. To identify and obtain cDNA for this protein, it was purified from rat plasma by size exclusion and copper chelate affinity chromatography, and amino acid sequences were obtained. These revealed a 190 kDa glycosylated protein identified as the macroglobulin, ?1inhibitorIII, the main macroglobulin of rodent blood plasma. Albumin (65 kDa) co-purified in variable amounts and was concluded to be a contaminant (although it transiently can bind the macroglobulin). The main macroglobulin in human blood plasma (?2-macroglobulin), homologous to ?1inhibitorIII, also bound copper tightly. Expression of ?1I3 (transcuprein) mRNA by the liver was examined in rats with and without copper deficiency, using quantitative PCR and Northern analysis. Protein expression was examined by Western blotting. Deficient rats with 40% less ceruloplasmin oxidase activity and liver copper concentrations expressed about twice as much ?1I3 mRNA, but circulating levels of transcuprein did not differ. Iron deficiency, which increased liver copper concentrations 3-fold, reduced transcuprein mRNA expression and 7circulating levels of transcuprein relative to what occurred in rats with normal or excess iron. We conclude that transcupreins are specific macroglobulins that not only carry zinc but also transport copper in the blood; and that their expression can be modulated by copper and iron availability. PMID:17363239

Liu, Nanmei; Lo, Louis Shi-li; Askary, S. Hassan; Jones, LaTrice; Kidane, Theodros Z.; Nguyen, Trisha Trang Minh; Goforth, Jeremy; Chu, Yu-Hsiang; Vivas, Esther; Tsai, Monta; Westbrook, Terence; Linder, Maria C.

2009-01-01

14

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

15

Iron deficiency in the pregnant rat has differential effects on maternal and fetal copper levels  

Microsoft Academic Search

Iron deficiency during pregnancy causes problems both for the mother and fetus. Iron deficiency is known to have secondary effects on copper metabolism. In this study, we use a rat model to examine the effect of iron deficiency on copper levels in maternal and fetal tissue. We assess whether the effects of iron deficiency on copper metabolism are due to

Lorraine Gambling; Susan Dunford; Harry J. McArdle

2004-01-01

16

Moessbauer Study on Barium Ferrite Magnetic Recording Media and Iron-Based Thin Films.  

NASA Astrophysics Data System (ADS)

Mossbauer spectroscopy and magnetic measurements (VSM) are employed to study pure and Co-Ti substituted barium ferrite and iron-based thin films. For substituted barium ferrite, the Mossbauer spectra are superposition of five subspectra because of the five different environments of the Fe^{3+} ions. We observe that spectral peak width broadens as Co-Ti substitution increases, eventually leading to very poor resolution. To date only low-temperature (4.2 K), high-field (9 T) Mossbauer spectroscopy has been employed to study uniaxal anisotropy of Co-Ti substituted barium ferrite. In this work, a series of Co-Ti substituted barium ferrite samples (x = 0.0, 0.15, 0.30, 0.45, 0.60, 0.75, and 0.90) have been studied at room temperature in an applied field only up to 0.8 T with transmission geometry Mossbauer spectroscopy. A difference in applied-field spectra compared with zero -field spectra is observed and implies that meaningful data on anisotropy can be obtained in moderate magnetic fields. A computer program for generating applied field Mossbauer spectra for powdered ferrimagnetic samples (11) has been implemented. Assuming a 2-sublattice structure, and comparing the simulated and experimental spectra, we obtain a value of the anisotropy field for pure barium ferrite at room temperature of 0.35 +/- 0.05 T. The results suggest that the 2-sublattice model may be extended to determine a value of the anisotropy field for each site in barium ferrite. Conversion electron Mossbauer spectrometry has been used to study two series of Fe films sputtered at high and low argon pressures with variable thickness of 50 to 1000 nm. The relative intensities of the (2, 5) components of the Zeeman sextet decrease with increasing film thickness for samples deposited at high argon pressure. In contrast, films deposited at low argon pressure exhibit only a small decrease in (2, 5) intensities over the thickness range studied, suggesting that moments retain in-plane orientation. The analysis shows that CEMS is a sensitive tool to investigate magnetic moment orientation in thin films and can supply useful information on the perpendicular anisotropy K_| of thin films which can not be obtained by VSM or torque measurements.

Hai, Jenny Ou.

17

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

18

Effect of oxygen, methyl mercaptan, and methyl chloride on friction behavior of copper-iron contacts  

NASA Technical Reports Server (NTRS)

Sliding friction experiments were conducted with an iron rider on a copper disk and a copper rider on an iron disk. The sputter cleaned iron and copper disk surfaces were saturated with oxygen, methyl mercaptan, and methyl chloride at atmospheric pressure. Auger emission spectroscopy was used to monitor the surfaces. Lower friction was obtained in all experiments with the copper rider sliding on the iron disk than when the couple was reversed. For both iron and copper disks, methyl mercaptan gave the best surface coverage and was most effective in reducing friction. For both iron and copper disks, methyl chloride was the least effective in reducing friction. With sliding, copper transferred to iron and iron to copper.

Buckley, D. H.

1978-01-01

19

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

PubMed Central

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

Yassur, Y; Zauberman, H; Zidon, M

1975-01-01

20

Static and dynamic photoinduced magnetic effects in yttrium-iron garnet lightly doped with barium ions  

SciTech Connect

In yttrium-iron garnet lightly doped with barium, direct measurements of the photoinduced changes in magnetostrictive strains disagree with those in magnetostriction constants at 78-100 K. This is attributed to a considerable photoinduced modification of the initial state in this sample due to a redistribution of the charge (during illumination) between cations of the ferromagnetic octahedral sublattice. In the same sample, the temperature dependence of the photoinduced disaccomodation of magnetic permeability characterizing the initial demagnetized state is measured and calculated. A change in the electron mechanism of the phenomenon during the transition to room temperature is shown. The conclusion about the promising prospects for using such samples for remagnetization by light is advanced.

Vorob'eva, N. V., E-mail: vnv@anrb.ru; Khalilov, R. Z. [Russian Academy of Sciences, Institute of Molecule and Crystal Physics (Russian Federation)

2012-04-15

21

Iron, copper, and iron regulatory protein 2 in Alzheimer's disease and related dementias.  

PubMed

Accumulating evidence implicates a role for altered iron and copper metabolism in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease (AD). However, imbalances in the levels of the various forms of iron at different stages of AD have not been examined. In this pilot study we extracted and measured the levels of loosely bound, non-heme and total iron and copper in the frontal cortex and hippocampus of patients with mild-moderate AD (n=3), severe AD (n=8) and dementia with Lewy bodies (DLB, n=6), using graphite furnace atomic absorption spectrometry (GFAAS). Additionally, the expression of iron regulatory protein 2 (IRP2) was examined in relation to the pathological hallmarks of AD and DLB, amyloid plaques, neurofibrillary tangles (NFT), and Lewy bodies, by immunohistochemistry. We found significantly decreased loosely bound iron in the hippocampal white matter of mild-moderate and severe AD patients and a trend towards increased non-heme iron in the hippocampal gray matter of severe AD patients. Furthermore, decreased levels of total copper were seen in severe AD and DLB frontal cortex compared to controls, suggesting an imbalance in brain metal levels in both AD and DLB. The decrease in loosely bound iron in mild-moderate AD patients may be associated with myelin breakdown seen in the beginning stages of AD and implicates that iron dysregulation is an early event in AD pathogenesis. PMID:17408857

Magaki, Shino; Raghavan, Ravi; Mueller, Claudius; Oberg, Kerby C; Vinters, Harry V; Kirsch, Wolff M

2007-05-11

22

1. Introduction Copper, along with iron active sites dominate the field of  

E-print Network

#12;1. Introduction Copper, along with iron active sites dominate the field of biological oxygen chemistry[1] and play important roles in homogeneous[2] and heterogeneous catalysis.[3, 4] Copper pro- teins heme ± iron centers).[8] The known copper proteins which are involved in dioxygen binding, activation

Chen, Peng

23

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

Microsoft Academic Search

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

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

2003-01-01

24

Copper  

MedlinePLUS

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

25

Iron oxide-copper-gold deposits: an Andean view  

Microsoft Academic Search

Iron oxide-copper-gold (IOCG) deposits, defined primarily by their elevated magnetite and\\/or hematite contents, constitute a broad, ill-defined clan related to a variety of tectono-magmatic settings. The youngest and, therefore, most readily understandable IOCG belt is located in the Coastal Cordillera of northern Chile and southern Peru, where it is part of a volcano-plutonic arc of Jurassic through Early Cretaceous age.

Richard H. Sillitoe

2003-01-01

26

Methods for making a supported iron-copper catalyst  

DOEpatents

A catalyst is described for the synthesis of hydrocarbons from CO+H.sub.2 utilizing a porous Al.sub.2 O.sub.3 support impregnated with iron and copper and optionally promoted with an alkali metal. The use of an Al.sub.2 O.sub.3 support results in the suppression of heavy waxes (C.sub.26 + hydrocarbons), particularly in slurry phase operation, when compared to unsupported or co-precipitated catalysts.

Dyer, Paul N. (Allentown, PA); Pierantozzi, Ronald (Macungie, PA)

1986-01-01

27

Role of Surface Precipitation in Copper Sorption by the Hydrous Oxides of Iron and Aluminum  

E-print Network

Role of Surface Precipitation in Copper Sorption by the Hydrous Oxides of Iron and Aluminum K. G precipitation; sorption; isotherms; X-ray diffraction; hydrous iron oxide; hydrous aluminum oxide; copper. INTRODUCTION Hydrous oxides of iron (HFO) and aluminum (HAO) are important mineral components of natural

Chorover, Jon

28

Identification of the man-made barium copper silicate pigments among some ancient Chinese artifacts through spectroscopic analysis.  

PubMed

This article describes the complementary application of non-invasive micro-Raman spectroscopy and energy dispersive X-ray fluorescence spectrometry to the characterization of some ancient Chinese silicate artifacts. A total of 28 samples dated from fourth century BC to third century AD were analyzed. The results of chemical analysis showed that the vitreous PbO-BaO-SiO2 material was used to sinter these silicate artifacts. The barium copper silicate pigments including BaCuSi4O10, BaCuSi2O6 and BaCu2Si2O7 were widely identified from colorful areas of the samples by Raman spectroscopy. In addition, other crystalline phases such as Fe2O3, BaSi2O5, BaSO4, PbCO3 and quartz were also identified. The present study provides very valuable information to trace the technical evolution of man-made barium copper silicate pigments and their close relationship with the making of ancient PbO-BaO-SiO2 glaze and glass. PMID:25541398

Li, Q H; Yang, J C; Li, L; Dong, J Q; Zhao, H X; Liu, S

2015-03-01

29

In-situ diagnostics for metalorganic chemical vapor deposition of yttrium barium copper oxide  

NASA Astrophysics Data System (ADS)

A new stagnation flow MOCVD research reactor is described that is designed to serve as a testbed to develop tools for "intelligent" thin film deposition, such as in-situ sensors and diagnostics, control algorithms, and thin film growth models. The reactor is designed in particular for the deposition of epitaxial YBa2Cu3O 7-delta on MgO, although with minor modifications it would be suitable for deposition of any metal-oxide thin films. The reactor is specifically designed to permit closed-loop thermal and stoichiometric control of the film growth process. Closed-loop control of precursor flow rates is accomplished by using ultraviolet absorption spectroscopy on each precursor line. Also integrated into the design is a Fourier Transform Infrared (FTIR) spectroscopy system which collects real-time, in-situ infrared polarized reflectance spectra of the film as it grows. Numerical simulation was used extensively to optimize the fluid dynamics and heat transfer to provide uniform fluxes to the substrate. As a result, thickness uniformity across the substrate is typically within 3% from the center to the edge of the substrate. Experimental studies of thin films grown in the Y/Ba/Cu/O system have been carried out. The films have been characterized by Rutherford Backscattering Spectrometry and X-ray Diffraction. Results indicate c-axis oriented grains with pure 1:2:3 phase YBCO, good spatial uniformity, and a low degree of c-axis wobble. Experimental growth data is used in a gas phase and surface chemistry model to calculate sticking coefficients for yttrium oxide, barium oxide, and copper oxide on YBCO. In-situ FTIR and Coherent Gradient Sensing (CGS) analysis of growing films has been performed, yielding accurate substrate temperature, film thickness monitoring, and full-field, real-time curvature maps of the films. In addition, we have implemented CGS to obtain full-field in-situ images of local curvature during oxygenation and deoxygenation of YBCO films. An analysis of the oxygen diffusion is performed, and diffusivity constants are presented for a variety of temperature and film conditions.

Tripathi, Ashok Burton

30

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

31

Iron and copper-associated cirrhosis in infants. Acquired metal toxicity or genetic disorder?  

PubMed

Iron and Copper are essential trace elements for growth and development of the human infant but are toxic in excess. Lethal cirrhotic syndromes in the neonate and infant have been associated with both copper and iron overload. The relative importance of underlying genetic susceptibility and acquired excess of iron or copper in the pathogenesis of these chronic metal toxicity states is controversial and both syndromes probably encompass a spectrum of conditions. PMID:9891605

Lockitch, G

1998-12-01

32

Copper complexation by 3-hydroxypyridin-4-one iron chelators: structural and iron competition studies.  

PubMed

Clinical trials of 1,2-dimethyl-3-hydroxypyridine-4-one (1) as an orally available iron chelator are presently underway in several centers. Discrepant reports of toxicity in human and animal studies have stimulated debate on the role of iron status and the availability of iron for chelation relative to other essential elements like copper in determining the clinical effects of 1. Therefore, we investigated the ability of 1, its 1,2-diethyl analog 2, and their iron chelates to complex copper. Both compounds formed tetracoordinate 2:1 Cu(II) complexes which X-ray structure analysis showed to be planar and coordinated through the oxygen atoms of the hydroxy ketone functionality. Potentiometric analysis revealed that these complexes dominated at physiological pH, although between pH 6 and 7 approximately equal amounts of the mono and bis complexes of Cu with 1 were present at equilibrium. Comparing the stepwise formation constants deduced from the stability constants of these complexes (log beta 2 = 21.7 +/- 0.8 (1) and 20.2 +/- 2.0 (2)) with those of their Fe(III) complexes (Motekaitis,R.J.;Martell,A.E.Inorg.Chim.Acta 1991, 183,71-80) leads to a prediction of insignificant copper complexation when equimolar iron is present and dissociation products are thermodynamically unimportant. However, displacement of Fe3+ occurred from both complexes with stoichiometric amounts of Cu2+, implicating the participation of metal hydrolysis products in the equilibria. We conclude that Cu(II) complexes of the 3-hydroxypyridin-4-one chelators are stable under physiological conditions and that copper can effect displacement of iron by these agents under circumstances where hydrolysis of the metals is important. PMID:7509878

el-Jammal, A; Howell, P L; Turner, M A; Li, N; Templeton, D M

1994-02-18

33

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

34

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...

35

Alterations of Serum Zinc, Copper and Iron Concentrations in Patients with Acute and Chronic Cutaneous Leishmaniasis  

Microsoft Academic Search

The aim of this study was to measure the alterations in serum zinc (Zn) copper (Cu) and iron (Fe) concentrations in patients with acute and chronic cutaneous leishmaniasis. Serum zinc and copper were measured by flameless atomic absorption spectrophotometer and serum iron concentration was measured by the Ferrozine method with commercial kits and assay was carried out by using an

M Faryadi; M Mohebali

2003-01-01

36

Electrochemical behaviour of iron and copper in a culture solution for Spirulina platensis  

Microsoft Academic Search

Cyclic voltammograms of iron and copper electrodes were run in sodium hydroxide, carbonate–bicarbonate buffer and culture media for Spirulina platensis at 30°C. Potentiostatic steady state polarisation curves for both electrode surfaces in these electrolytes were performed in the presence and the absence of S. platensis at fixed temperature. Corrosion potential and corrosion current density values of iron and copper were

R. Malgor; G. Heijo; L. Romero; C. F. Zinola

1998-01-01

37

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

38

Sequential injection lab-on-valve simultaneous spectrophotometric determination of trace amounts of copper and iron.  

PubMed

A sequential injection (SI) method in a lab-on-valve (LOV) format for simultaneous spectrophotometric determination of copper and iron has been devised. The detection chemistry is based on the complex formation of 2-(5-bromo-2-pyridylazo)-5-[N-n-propyl-N-(3-sulfopropyl)amino]aniline (5-Br-PSAA) with copper(II) and/or iron(II) at pH 4.6. Copper(II) reacts with 5-Br-PSAA to form the complex which has an absorption maximum at 580 nm but iron(III) does not react. In the presence of a reducing agent only iron(II)-5-Br-PSAA complex is formed and detected at 558 nm. Under the optimum experimental conditions, the determinable ranges are 0.1-2 mg l(-1) for copper and 0.1-5 mg l(-1) for iron, respectively, with a sampling rate of 18 h(-1). The limits of detection are 50 microg l(-1) for copper and 25 microg l(-1) for iron. The relative standard deviations (n=15) are 2% for 0.5 mg l(-1) copper and 1.8% for 0.5 mg l(-1) iron when determined in standard solutions. The recoveries range between 96 and 105% when determining 0.25-2 mg l(-1) of copper and 0.2-5 mg l(-1) of iron in artificial mixtures at copper/iron ratios of 1:10 to 5:1. The proposed SI-LOV method is successfully applied to the simultaneous determination of copper and iron in multi-element standard solution and in industrial wastewater samples. PMID:18970353

Ohno, Shinsuke; Teshima, Norio; Sakai, Tadao; Grudpan, Kate; Polasek, Miroslav

2006-01-15

39

Copper.  

PubMed

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

Barceloux, D G

1999-01-01

40

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

41

Copper deficiency leads to anemia, duodenal hypoxia, upregulation of HIF-2? and altered expression of iron absorption genes in mice.  

PubMed

Iron and copper are essential trace metals, actively absorbed from the proximal gut in a regulated fashion. Depletion of either metal can lead to anemia. In the gut, copper deficiency can affect iron absorption through modulating the activity of hephaestin - a multi-copper oxidase required for optimal iron export from enterocytes. How systemic copper status regulates iron absorption is unknown. Mice were subjected to a nutritional copper deficiency-induced anemia regime from birth and injected with copper sulphate intraperitoneally to correct the anemia. Copper deficiency resulted in anemia, increased duodenal hypoxia and Hypoxia inducible factor 2? (HIF-2?) levels, a regulator of iron absorption. HIF-2? upregulation in copper deficiency appeared to be independent of duodenal iron or copper levels and correlated with the expression of iron transporters (Ferroportin - Fpn, Divalent Metal transporter - Dmt1) and ferric reductase - Dcytb. Alleviation of copper-dependent anemia with intraperitoneal copper injection resulted in down regulation of HIF-2?-regulated iron absorption genes in the gut. Our work identifies HIF-2? as an important regulator of iron transport machinery in copper deficiency. PMID:23555700

Matak, Pavle; Zumerle, Sara; Mastrogiannaki, Maria; El Balkhi, Souleiman; Delga, Stephanie; Mathieu, Jacques R R; Canonne-Hergaux, François; Poupon, Joel; Sharp, Paul A; Vaulont, Sophie; Peyssonnaux, Carole

2013-01-01

42

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 ...

43

Divalent metal transporter 1 (Dmt1) Mediates Copper Transport in the Duodenum of Iron-Deficient Rats and When Overexpressed in Iron-Deprived HEK-293 Cells12  

PubMed Central

Intracellular copper-binding proteins (metallothionein I/II) and a copper exporter (Menkes copper-transporting ATPase) are upregulated in duodenal enterocytes from iron-deficient rats, consistent with copper accumulation in the intestinal mucosa. How copper enters enterocytes during iron deficiency is, however, not clear. Divalent metal transporter 1 (Dmt1), the predominant iron importer in the mammalian duodenum, also transports other metal ions, possibly including copper. Given this possibility and that Dmt1 expression is upregulated by iron deprivation, we sought to test the hypothesis that Dmt1 transports copper during iron deficiency. Two model systems were utilized: the Belgrade (b) rat, expressing mutant Dmt1, and an inducible Dmt1-overexpression cell culture system. Mutant rats (b/b) were fed a semipurified, AIN93G-based control diet and phenotypically normal littermates (+/b) were fed control or iron-deficient diets for ?14 wk. An everted gut sleeve technique and a colorimetric copper quantification assay were utilized to assess duodenal copper transport. The control diet-fed +/b rats had normal hematological parameters, whereas iron-deprived +/b and b/b rats were iron deficient and Dmt1 mRNA and protein levels increased. Importantly, duodenal copper transport was similar in the control +/b and b/b rats; however, it significantly increased (?4-fold) in the iron-deprived +/b rats. Additional experiments in Dmt1 overexpressing HEK-293 cells showed that copper (64Cu) uptake was stimulated (?3-fold) in the presence of an iron chelator. Dmt1 transcript stabilization due to a 3? iron-responsive element was also documented, likely contributing to increased transport activity. In summary, these studies suggest that Dmt1 enhances copper uptake into duodenal enterocytes during iron deprivation. PMID:24089420

Jiang, Lingli; Garrick, Michael D.; Garrick, Laura M.; Zhao, Lin; Collins, James F.

2013-01-01

44

Divalent metal transporter 1 (Dmt1) mediates copper transport in the duodenum of iron-deficient rats and when overexpressed in iron-deprived HEK-293 cells.  

PubMed

Intracellular copper-binding proteins (metallothionein I/II) and a copper exporter (Menkes copper-transporting ATPase) are upregulated in duodenal enterocytes from iron-deficient rats, consistent with copper accumulation in the intestinal mucosa. How copper enters enterocytes during iron deficiency is, however, not clear. Divalent metal transporter 1 (Dmt1), the predominant iron importer in the mammalian duodenum, also transports other metal ions, possibly including copper. Given this possibility and that Dmt1 expression is upregulated by iron deprivation, we sought to test the hypothesis that Dmt1 transports copper during iron deficiency. Two model systems were utilized: the Belgrade (b) rat, expressing mutant Dmt1, and an inducible Dmt1-overexpression cell culture system. Mutant rats (b/b) were fed a semipurified, AIN93G-based control diet and phenotypically normal littermates (+/b) were fed control or iron-deficient diets for ~14 wk. An everted gut sleeve technique and a colorimetric copper quantification assay were utilized to assess duodenal copper transport. The control diet-fed +/b rats had normal hematological parameters, whereas iron-deprived +/b and b/b rats were iron deficient and Dmt1 mRNA and protein levels increased. Importantly, duodenal copper transport was similar in the control +/b and b/b rats; however, it significantly increased (~4-fold) in the iron-deprived +/b rats. Additional experiments in Dmt1 overexpressing HEK-293 cells showed that copper ((64)Cu) uptake was stimulated (?3-fold) in the presence of an iron chelator. Dmt1 transcript stabilization due to a 3' iron-responsive element was also documented, likely contributing to increased transport activity. In summary, these studies suggest that Dmt1 enhances copper uptake into duodenal enterocytes during iron deprivation. PMID:24089420

Jiang, Lingli; Garrick, Michael D; Garrick, Laura M; Zhao, Lin; Collins, James F

2013-12-01

45

Optimization of copper cementation process by iron using central composite design experiments  

Microsoft Academic Search

In this study, the effects of various experimental parameters on the cementation yield of copper by iron were investigated statistically. A statistical experimental design based on the second-order central composite rotatable design (CCRD) was planned fixing the cementation period at 2h. The experimental design was done at five levels of the operating parameters which were the initial copper concentration, temperature,

W. Djoudi; F. Aissani-Benissad; S. Bourouina-Bacha

2007-01-01

46

A mitochondrial-vacuolar signaling pathway in yeast that affects iron and copper metabolism.  

PubMed

Mitochondria utilize iron, but the transporters that mediate mitochondrial iron uptake and efflux are largely unknown. Cells with a deletion in the vacuolar iron/manganese transporter Ccc1p are sensitive to high iron. Overexpression of MRS3 or MRS4 suppresses the high iron sensitivity of Deltaccc1 cells. MRS3 and MRS4 have recently been suggested to encode mitochondrial iron transporters. We demonstrate that deletion of MRS3 and MRS4 severely affects cellular and mitochondrial metal homeostasis, including a reduction in cytosolic and mitochondrial iron acquisition. We show that vacuolar iron transport is increased in Deltamrs3Deltamrs4 cells, resulting in decreased cytosolic iron and activation of the iron-sensing transcription factor Aft1p. Activation of Aft1p leads to increased expression of the high affinity iron transport system and increased iron uptake. Deletion of CCC1 in Deltamrs3Deltamrs4 cells restores cellular and mitochondrial iron homeostasis to near normal levels. Deltamrs3Deltamrs4 cells also show increased resistance to cobalt but decreased resistance to copper and cadmium. These phenotypes are also corrected by deletion of CCC1 in Deltamrs3Deltamrs4 cells. Decreased copper resistance in Deltamrs3Deltamrs4 cells results from activation of Aft1p by Ccc1p-mediated iron depletion, as deletion of CCC1 or AFT1 in Deltamrs3Deltamrs4 cells restores copper resistance. These results suggest that deletion of mitochondrial proteins can alter vacuolar metal homeostasis. The data also indicate that increased expression of the AFT1-regulated gene(s) can disrupt copper homeostasis. PMID:15161905

Li, Liangtao; Kaplan, Jerry

2004-08-01

47

Impairment of interrelated iron- and copper homeostatic mechanisms in brain contributes to the pathogenesis of neurodegenerative disorders.  

PubMed

Iron and copper are important co-factors for a number of enzymes in the brain, including enzymes involved in neurotransmitter synthesis and myelin formation. Both shortage and an excess of iron or copper will affect the brain. The transport of iron and copper into the brain from the circulation is strictly regulated, and concordantly protective barriers, i.e., the blood-brain barrier (BBB) and the blood-cerebrospinal fluid (CSF) barrier (BCB) have evolved to separate the brain environment from the circulation. The uptake mechanisms of the two metals interact. Both iron deficiency and overload lead to altered copper homeostasis in the brain. Similarly, changes in dietary copper affect the brain iron homeostasis. Moreover, the uptake routes of iron and copper overlap each other which affect the interplay between the concentrations of the two metals in the brain. The divalent metal transporter-1 (DMT1) is involved in the uptake of both iron and copper. Furthermore, copper is an essential co-factor in numerous proteins that are vital for iron homeostasis and affects the binding of iron-response proteins to iron-response elements in the mRNA of the transferrin receptor, DMT1, and ferroportin, all highly involved in iron transport. Iron and copper are mainly taken up at the BBB, but the BCB also plays a vital role in the homeostasis of the two metals, in terms of sequestering, uptake, and efflux of iron and copper from the brain. Inside the brain, iron and copper are taken up by neurons and glia cells that express various transporters. PMID:23055972

Skjørringe, Tina; Møller, Lisbeth Birk; Moos, Torben

2012-01-01

48

Impairment of Interrelated Iron- and Copper Homeostatic Mechanisms in Brain Contributes to the Pathogenesis of Neurodegenerative Disorders  

PubMed Central

Iron and copper are important co-factors for a number of enzymes in the brain, including enzymes involved in neurotransmitter synthesis and myelin formation. Both shortage and an excess of iron or copper will affect the brain. The transport of iron and copper into the brain from the circulation is strictly regulated, and concordantly protective barriers, i.e., the blood-brain barrier (BBB) and the blood-cerebrospinal fluid (CSF) barrier (BCB) have evolved to separate the brain environment from the circulation. The uptake mechanisms of the two metals interact. Both iron deficiency and overload lead to altered copper homeostasis in the brain. Similarly, changes in dietary copper affect the brain iron homeostasis. Moreover, the uptake routes of iron and copper overlap each other which affect the interplay between the concentrations of the two metals in the brain. The divalent metal transporter-1 (DMT1) is involved in the uptake of both iron and copper. Furthermore, copper is an essential co-factor in numerous proteins that are vital for iron homeostasis and affects the binding of iron-response proteins to iron-response elements in the mRNA of the transferrin receptor, DMT1, and ferroportin, all highly involved in iron transport. Iron and copper are mainly taken up at the BBB, but the BCB also plays a vital role in the homeostasis of the two metals, in terms of sequestering, uptake, and efflux of iron and copper from the brain. Inside the brain, iron and copper are taken up by neurons and glia cells that express various transporters. PMID:23055972

Skjørringe, Tina; Møller, Lisbeth Birk; Moos, Torben

2012-01-01

49

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

50

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

51

Biochemical Evolution of Iron and Copper Proteins, Substances Vital to Life  

ERIC Educational Resources Information Center

Summarizes studies in the area of biochemical evolution of iron, copper, and heme proteins to provide an historical outline. Included are lists of major kinds of proteins and enzymes and charts illustrating electron flow in a cytochrome electron transport system and interconversion of jerrous to ferric ion in iron metabolism. (CC)

Frieden, Earl

1974-01-01

52

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. PMID:25030305

2014-01-01

53

IN-HOUSE CORROSION RESEARCH EMPHASIZING LEAD, COPPER AND IRON  

EPA Science Inventory

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

54

Removal of heavy metals and dyes by supported nano zero-valent iron on barium ferrite microfibers.  

PubMed

The binary nano zero-valent iron/barium ferrite (NZVI/BFO) microfibers with uniform diameters and high porosity were prepared by the organic gel-thermal selective reduction process. The composite microfibers are fabricated from nano zero-valent iron and nano BaFe12O19 grains. The effects of pH, adsorbent dosage, and contact time on the adsorption of heavy metals and dyes have been investigated. The adsorption isotherms of heavy metals and dyes on the microfibers are well described by the Langmuir model, in which the estimated adsorption capacities are 14.5, 29.9, 68.3 and 110.4 mg/g for Pb(II), As(V), Congo red and methylene blue, respectively. After five cycles, these microfibers still exhibit a high removal efficiency for As(V), Pb(II), Congo red and methylene blue. The enhanced adsorption characteristics can be attributed to the porous structure, strong surface activity and electronic hopping. Therefore, the magnetic NZVI/BFO microfibers can be used as an efficient, fast and high capacity adsorbent for heavy metals and dyes removal. PMID:24758012

Yang, Xinchun; Shen, Xiangqian; Jing, Maoxiang; Liu, Ruijiang; Lu, Yi; Xiang, Jun

2014-07-01

55

Reduction of copper(II) by iron(II).  

PubMed

Laboratory and field investigations have clearly demonstrated the important role of reduced iron (Fe(II)) in reductive transformations of first-row transition metal species. However, interactions of Fe(II) and copper (Cu) are not clearly understood. This study examined the reduction of Cu(II) by Fe(II) in stirred-batch experiments at pH 5.2 and 5.5 as influenced by chloride (Cl-) concentration (0.002-0.1 M), initial metal concentration (0.1-9.1 mM), and reaction time (1-60 min) under anoxic conditions. Reduction of Cu(II) to Cu(I) by dissolved Fe(II) was rapid under all experimental conditions and the stability of the products explains the driving force for the redox reaction. Under conditions of low [Cl-] and high initial metal concentration, >40% of total Cu and Fe were removed from solution after 1 min, which accompanied formation of a brownish-red precipitate. X-ray diffraction (XRD) patterns of the precipitates revealed the presence of cuprite (Cu2O), a Cu(I) mineral, based on d-spacings located at 0.248, 0.215, 0.151, and 0.129 nm. Fourier transform infrared (FTIR) spectroscopy corroborated XRD data for the presence of Cu2O, with features located at 518, 625, and 698 cm(-1). Increasing [Cl-] stabilized the dissolved Cu(I) product against Cu2O precipitation and resulted in more Fe precipitated from solution (relative to Cu) that appears to be present as poorly crystalline lepidocrocite (gamma-FeOOH). This process may be important in anoxic soil environments, where dissolved Fe(II) levels can accumulate. PMID:16091606

Matocha, C J; Karathanasis, A D; Rakshit, S; Wagner, K M

2005-01-01

56

Urinary excretion of copper, zinc and iron with and without D-penicillamine administration in relation to hepatic copper concentration in dogs.  

PubMed

Hereditary copper-associated hepatitis in dogs resembles Wilson's disease, a copper storage disease in humans. Values for urinary copper excretion are well established in the diagnostic protocol of Wilson's disease, whereas in dogs these have not been evaluated. The objectives of this study were to characterize both basal and D-penicillamine induced urinary copper, zinc and iron excretion in dogs in relation to hepatic copper concentration. Beagles, Beagle-Bedlington terrier cross-breeds homozygous for the COMMD1 gene mutation that causes copper toxicosis, and Labrador retrievers with normal or increased hepatic copper concentrations were investigated. The hepatic copper phenotype was determined by histological evaluation of liver biopsies and measurement of the hepatic copper concentration by instrumental neutron activation analysis. Urinary excretion of copper, iron and zinc was measured via inductively coupled plasma optical emission spectrometry under basal conditions and after oral administration of a single dose (20mg/kg bodyweight) of the chelator D-penicillamine. There was a rapid increase in urinary excretion of copper and zinc, but not iron after D-penicillamine administration. This increase was not different between dogs with high or normal hepatic copper concentrations. D-penicillamine-induced urinary copper excretion and the copper/creatinine ratio did not correlate with hepatic copper concentrations in the dogs studied, although basal urinary copper/zinc ratios did correlate with hepatic copper concentrations in Labrador retrievers. The latter parameter may be useful in diagnostic and follow-up protocols for copper-associated hepatitis in Labrador retrievers. PMID:23583003

Fieten, H; Hugen, S; van den Ingh, T S G A M; Hendriks, W H; Vernooij, J C M; Bode, P; Watson, A L; Leegwater, P A J; Rothuizen, J

2013-08-01

57

a Positron Study of the Electronic Structure of Yttrium Barium Copper Oxide.  

NASA Astrophysics Data System (ADS)

The work described in this thesis is concerned with a study of the electronic structure of the high T _{c} superconductor YBa _2Cu_3O _7 using the technique of two dimensional angular correlation of annihilation radiation (2D-ACAR). We have studied this compound with a view to clarifying whether YBa_2Cu_3O _7 possess a Fermi surface. The numerous different theories that have been proposed to explain the superconductivity phase of these types of materials can be classified into two main groups. The theories in the first group assume the existence of a conventional Fermi fluid and Fermi surface. The alternative more exotic models do not require a Fermi surface but are based on the Mott-Hubbard model of strongly correlated charge and spin excitations. Prior to this work all 2D-ACAR studies of YBa _2Cu_3O _7 involved twinned crystals and modest statistics and little of significance was learned other than that, consistent with that of predictions of theory, the positron was preferentially annihilating on the copper-oxygen chains. The studies of untwinned crystals of YBa_2Cu _3O_7, herein described are of much higher statistics and resulted in one of the clearest imaginable manifestations of a Fermi surface in the form of an extended discontinuity in the measured momentum spectrum. This discontinuity is even more apparent in the LCW-folded spectrum with a form and profile in substantial agreement with the theoretical predictions of a Gamma-X electron ridge Fermi surface section arising from states in the Cu-O chains.

Haghighi, Hossein

58

Herbal infusions as a source of calcium, magnesium, iron, zinc and copper in human nutrition.  

PubMed

The study material consisted of five herbs: chamomile (flowers), mint (leaves), St John's wort (flowers and leaves), sage (leaves) and nettle (leaves), sourced from three producers. The calcium, magnesium, iron, zinc and copper contents were determined for both dried herb samples and prepared infusions, and the extraction rates were calculated. Mineral components were determined using atomic absorption spectrometry. Analysis showed that the contents of individual elements in herbs and infusions depended on the type of raw material, as well as on its origin. Moreover, it was found that iron penetrated the herbal infusions to the lowest degree (4.4-12.4%), while copper did so to the highest (26.7-50.7%). It is felt that in average consumption the herbal infusions are not important as calcium, magnesium, iron, zinc and copper sources in human nutrition. PMID:21916535

Suliburska, Joanna; Kaczmarek, Karolina

2012-03-01

59

Some new chromogens for iron, cobalt, and copper Substituted hydrazidines and 1,2,4-triazines containing the ferroin group.  

PubMed

The spectral characteristics and solution conditions requisite for formation of the iron(II), cobalt(II), and copper(I) complexes of some newly synthesised compounds containing the ferroin functional grouping have been determined. These properties are useful for evaluation of the possible analytical effectiveness of the compounds as spectrophotometric reagents for the determination of iron, cobalt, and copper. PMID:18959951

Schilt, A A

1966-07-01

60

Electrically and magnetically tunable phase shifters based on a barium strontium titanate-yttrium iron garnet layered structure  

NASA Astrophysics Data System (ADS)

We report on the tuning of permittivity and permeability of a ferroelectric/ferromagnetic bilayer structure which can be used as a microwave phase shifter with two degrees of tuning freedom. The structure was prepared by the growth of a yttrium iron garnet (YIG) layer on a gadolinium gallium garnet substrate by liquid phase epitaxy, the growth of a barium strontium titanate (BST) layer on the YIG layer through pulsed laser deposition, and then the fabrication of a coplanar waveguide on the top of BST through e-beam evaporation and trilayer liftoff techniques. The phase shifters exhibit a differential phase shift of 38°/cm at 6 GHz through permittivity tuning under an applied electric field of ˜75 kV/cm and a static magnetic field of 1700 Oe. By tuning the permeability through the applied magnetic field we increase the differential phase shift to 52°/cm and simultaneously obtain a better match to the zero applied electric field condition, resulting in an improvement in the return loss from 22.4 to 24.9 dB. Additionally, we demonstrate the use of a lead magnesium niobate-lead titanate (PMN-PT) layer to tune the permeability of the YIG layer. This tuning relies on the piezoelectric and magnetostrictive effects of PMN-PT and YIG, respectively. Tuning of the ferromagnetic response through strain and magnetostriction as opposed to applied magnetic field can potentially pave the way for low power consumption, continuously and rapidly tunable, impedance matched phase shifters.

Leach, J. H.; Liu, H.; Avrutin, V.; Rowe, E.; Özgür, Ü.; Morkoç, H.; Song, Y.-Y.; Wu, M.

2010-09-01

61

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. 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

62

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

63

Lenticular nucleus hyperechogenicity in Wilson's disease reflects local copper, but not iron accumulation.  

PubMed

In patients with Wilson's disease (WD) transcranial brain sonography typically reveals areas of increased echogenicity (hyperechogenicity) of the lenticular nucleus (LN). Correlation with T2-hypointensity on magnetic resonance images suggested that LN hyperechogenicity in WD is caused by trace metal accumulation. Accumulation of both, copper and iron, in the brain of WD patients has been reported. The present study was designed to elucidate whether LN hyperechogenicity in WD reflects accumulation of copper or iron. Post-mortem brains of 15 WD patients and one non-WD subject were studied with ultrasonography in an investigator-blinded fashion. LN hyperechogenicity was measured planimetrically by manual tracing as well as using digitized image analysis. The putaminal copper content was determined in samples of 11 WD brains and the non-WD brains using inductively coupled plasma mass spectrometry, and iron content was assessed using flame atomic absorption spectroscopy. LN was normal on ultrasonography only in the non-WD brain, but abnormal (hyperechogenic) in all WD brains. Digitized image analysis measures of LN hyperechogenicity and, by trend, manual measures correlated with putaminal copper content (Pearson test; digitized: r = 0.77, p = 0.04; manual: r = 0.57, p = 0.051) but not with iron content (each, p > 0.18). LN hyperechogenicity measures were unrelated to age at death of patients, age at onset of WD, WD duration, age of brain specimen, serum copper or serum ceruloplasmin (each, p > 0.1). We conclude that LN hyperechogenicity in WD reflects copper, but not iron accumulation. Further studies are warranted to elucidate the use of transcranial brain sonography for monitoring therapeutic effects of chelating agents in WD patients. PMID:24615184

Walter, Uwe; Skowro?ska, Marta; Litwin, Tomasz; Szpak, Gra?yna Maria; Jab?onka-Salach, Katarzyna; Skoloudík, David; Bulska, Ewa; Cz?onkowska, Anna

2014-10-01

64

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

Microsoft Academic Search

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

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

1985-01-01

65

Gas tungsten arc welding of nickel-copper to nickel-chromium-iron. Welding procedure specification  

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 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.

1985-08-01

66

Gas tungsten arc welding of nickel-copper to nickel-chromium-iron. Welding procedure specification  

Microsoft Academic Search

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 of 0.035 to 0.432 inch; filler metal is ERNiCu-7 (F-42); shielding gas is argon.

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

1985-01-01

67

IRON ABSORPTION AND INTESTINAL HEPHAESTIN PROTEIN IN COPPER-DEFICIENT RATS  

Technology Transfer Automated Retrieval System (TEKTRAN)

More than 100 years ago, a connection between copper (Cu) and iron (Fe) metabolism was established when some forms of anemia were found to respond to treatment with Cu but not Fe. It was later discovered that the Cu-dependent plasma ferroxidase, ceruloplasmin, was associated with Fe homeostasis. Cu ...

68

Metal passivity as mechanism of metal carcinogenesis: Chromium, nickel, iron, copper, cobalt, platinum, molybdenum  

Microsoft Academic Search

For the transition metals chromium, nickel, iron, copper, cobalt, platinum, and molybdenum, mechanisms of stable bonding in biochemistry (emphasis on carcinogenic mechanisms), chemistry, industrial chemistry, as well as epidemiological, occupational, orthopedic (implant devices) effects related to carcinogenesis, were reviewed. Hypothetically, the propensity to stable bonding (inertness), which ensures the metals’ performance capacity for consumers and industrial application, relates to their

Cornelia Richardson-Boedler

2007-01-01

69

Calcium, copper, iron, magnesium, silicon and zinc content of hair in Parkinson's disease  

Microsoft Academic Search

The aetiology of Parkinson's disease (PD) is still unknown, but some hypotheses have focused on the imbalances in body levels of metals as co-factors of risk. To assess whether hair could be a reliable marker of possible changes, calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), silicon (Si) and zinc (Zn) were determined in hair from 81 patients affected by

Giovanni Forte; Alessandro Alimonti; Nicola Violante; Marco Di Gregorio; Oreste Senofonte; Francesco Petrucci; Giuseppe Sancesario; Beatrice Bocca

2005-01-01

70

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

71

Investigating the role of transferrin in the distribution of iron, manganese, copper, and zinc.  

PubMed

The essential role of transferrin in mammalian iron metabolism is firmly established. Integral to our understanding of transferrin, studies in hypotransferrinemic mice, a model of inherited transferrin deficiency, have demonstrated that transferrin is essential for iron delivery for erythropoiesis and in the regulation of expression of hepcidin, a hormone that inhibits macrophage and enterocyte iron efflux. Here we investigate a potential role for transferrin in the distribution of three other physiologic metals, manganese, copper, and zinc. We first assessed metal content in transferrin-rich fractions of wild-type mouse sera and demonstrate that although both iron and manganese cofractionated predominantly with transferrin, the absolute levels of manganese are several orders of magnitude lower than those of iron. We next measured metal content in multiple tissues in wild-type and hypotransferrinemic mice of various ages. Tissue metal imbalances were severe for iron and minimal to moderate for some metals in some tissues in hypotransferrinemic mice. Metal levels measured in a transferrin-replete yet hepcidin-deficient and iron-loaded mouse strain suggested that the observed imbalances in tissue copper, zinc, and manganese levels were not all specific to hypotransferrinemic mice or caused directly by transferrin deficiency. Overall, our results suggest that transferrin does not have a primary role in the distribution of manganese, copper, or zinc to tissues and that the abnormalities observed in tissue manganese levels are not attributable to a direct role for transferrin in manganese metabolism but rather are attributable to an indirect effect of transferrin deficiency on hepcidin expression and/or iron metabolism. PMID:24567067

Herrera, Carolina; Pettiglio, Michael A; Bartnikas, Thomas B

2014-08-01

72

Zinc Pyrithione Inhibits Yeast Growth through Copper Influx and Inactivation of Iron-Sulfur Proteins?†  

PubMed Central

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.

2011-01-01

73

Controlling lead and copper corrosion and sequestering of iron and manganese  

SciTech Connect

With the recently enacted Lead and Copper Rule (LCR), many utilities are faced with the conflict of meeting the requirements of the Rule and controlling aesthetic problems caused by source water iron and manganese. The most common approach for utilities to control ``red and black water`` is to add a polyphosphate based compound. However, the higher pH required for control of lead and copper solubility reduces the effectiveness of polyphosphate to sequester iron and manganese. There is also the threat that polyphosphate may complex lead and copper and increase their concentration. An alternative treatment approach, sodium silicate addition, was evaluated at medium sized water system with elevated source water iron (0.30--2.27 mg/L) and manganese (0.11--0.27 mg/L). The goal of the study was to examine the viability of sodium silicate to simultaneously control red water complaints, and reduce lead and copper concentrations. Samples for a wide range of water quality parameters were collected before initiating treatment (5 months) and after treatment to gauge the effectiveness of the approach.

Clement, J.A. [Black and Veatch, Cambridge, MA (United States); Schock, M.; Lytle, D. [Environmental Protection Agency, Cincinnati, OH (United States)

1994-12-31

74

Composite nanoplatelets combining soft-magnetic iron oxide with hard-magnetic barium hexaferrite.  

PubMed

By coupling two different magnetic materials inside a single composite nanoparticle, the shape of the magnetic hysteresis can be engineered to meet the requirements of specific applications. Sandwich-like composite nanoparticles composed of a hard-magnetic Ba-hexaferrite (BaFe12O19) platelet core in between two soft-magnetic spinel iron oxide maghemite (?-Fe2O3) layers were synthesized using a new, simple and inexpensive method based on the co-precipitation of Fe(3+)/Fe(2+) ions in an aqueous suspension of hexaferrite core nanoparticles. The required close control of the supersaturation of the precipitating species was enabled by the controlled release of the Fe(3+) ions from the nitrate complex with urea ([Fe((H2N)2C[double bond, length as m-dash]O)6](NO3)3) and by using Mg(OH)2 as a solid precipitating agent. The platelet Ba-hexaferrite nanoparticles of different sizes were used as the cores. The controlled coating resulted in an exclusively heterogeneous nucleation and the topotactic growth of the spinel layers on both basal surfaces of the larger hexaferrite nanoplatelets. The direct magnetic coupling between the core and the shell resulted in a strong increase of the energy product |BH|max. Ultrafine core nanoparticles reacted with the precipitating species and homogeneous product nanoparticles were formed, which differ in terms of the structure and composition compared to any other compound in the BaO-Fe2O3 system. PMID:25583312

Primc, D; Makovec, D

2015-01-28

75

Serum iron, zinc, and copper concentration in premature graying of hair.  

PubMed

Premature graying of hair with unclear etiology, which is known as premature canities, is a common cause of referrals to the dermatologists. We assessed the relationship between serum iron, copper, and zinc concentrations with premature canities. This study was conducted on patients under 20 years old suffering from premature canities, having a minimum of ten gray hair fibers, and referring to university hospitals of Isfahan (Iran). The results were compared with age-sex-matched controls. Demographic data and disease characteristics were recorded for two groups. We studied serum iron, copper, and zinc concentrations of 66 patients and 66 controls using atomic absorption and Ferrozine methods. The mean age of studied cases was 17.8?±?2.0 years, and the mean age of the onset of canities was 15.5?±?3.2 years with no significant difference between males and females (P?>?0.05). Serum copper concentration was significantly lower in patients compared with controls (90.7?±?37.4 vs. 105.3?±?50.2 ?g/dL, P?=?0.048), but serum iron concentration was significantly lower in controls compared to patients (88.8?±?39.5 vs. 108.3?±?48.4 ?g/dL, P?=?0.008). Also, there was no significant difference between patients and controls in serum zinc concentration (114.8?±?67.8 vs. 108.2?±?49.9 ?g/dL, P?=?0.285). According to these results, among copper, zinc, and iron, a low serum copper concentration may play a role in premature graying of hairs in our society. Further studies are needed to find the underlying mechanism of this relationship. PMID:21979243

Fatemi Naieni, Farahnaz; Ebrahimi, Bahareh; Vakilian, Hamid Reza; Shahmoradi, Zabihollah

2012-04-01

76

Copper, nickel, and iron in plumage of three upland gamebird species from non-contaminated environments  

SciTech Connect

High levels of atmospheric contamination and particulate fallout characterizing the Industrial Basin of the copper-nickel smelting operations at Sudbury, Ontario, were shown to be reflected in the feather chemistry of resident ruffed grouse populations. Of considerable concern, however, is the paucity of information on background concentrations of elemental metals that could be considered normal for non-contaminated environments. The present report examines concentrations of copper, nickel and iron in the plumage of three tetraonid species collected from remote and undisturbed areas in Northern Ontario and Quebec.

Parker, G.H.

1985-12-01

77

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

78

Barium Sulfate  

MedlinePLUS

Cheetah® ... Barium sulfate is used to help doctors examine the esophagus (tube that connects the mouth and stomach), stomach, ... dimensional pictures of the inside of the body). Barium sulfate is in a class of medications called radiopaque ...

79

Content of total iron, copper and manganese in liver of animals during hypokinesia, muscle activity and process of recovery  

NASA Technical Reports Server (NTRS)

It is shown that the content of total iron, copper and manganese in the liver of animals is altered depending on the intensity and duration of their swimming. Hypodynamia for 7 days does not alter the concentration of iron, but sufficiently increases the content of copper and manganese. The barometric factor effectively influences the maintenance of constancy in the content of microelements accumulated in the liver after intensive muscle activity.

Potapovich, G. M.; Taneyeva, G. V.; Uteshev, A. B.

1980-01-01

80

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. PMID:21902275

2011-01-01

81

Serum ceruloplasmin protein expression and activity increases in iron-deficient rats and is further enhanced by higher dietary copper intake  

PubMed Central

Increases in serum and liver copper content are noted during iron deficiency in mammals, suggesting that copper-dependent processes participate during iron deprivation. One point of intersection between the 2 metals is the liver-derived, multicopper ferroxidase ceruloplasmin (Cp) that is important for iron release from certain tissues. The current study sought to explore Cp expression and activity during physiologic states in which hepatic copper loading occurs (eg, iron deficiency). Weanling rats were fed control or low iron diets containing low, normal, or high copper for ? 5 weeks, and parameters of iron homeostasis were measured. Liver copper increased in control and iron-deficient rats fed extra copper. Hepatic Cp mRNA levels did not change; however, serum Cp protein was higher during iron deprivation and with higher copper consumption. In-gel and spectrophotometric ferroxidase and amine oxidase assays demonstrated that Cp activity was enhanced when hepatic copper loading occurred. Interestingly, liver copper levels strongly correlated with Cp protein expression and activity. These observations support the possibility that liver copper loading increases metallation of the Cp protein, leading to increased production of the holo enzyme. Moreover, this phenomenon may play an important role in the compensatory response to maintain iron homeostasis during iron deficiency. PMID:21768302

Ranganathan, Perungavur N.; Lu, Yan; Jiang, Lingli; Kim, Changae

2011-01-01

82

Oxidation of cyclohexane over iron and copper salen complexes simultaneously encapsulated in zeolite Y  

Microsoft Academic Search

Iron and copper salen complexes have been simultaneously encapsulated in zeolite Y by using the flexible ligand method, as substantiated by infrared spectroscopy, diffuse reflectance UV–vis spectroscopy, thermo-gravimetric and differential-thermal analyses and N2 adsorption\\/desorption experiments at ?196°C. The prepared material showed much higher activity than the neat Cu(salen) and Fe(salen) or the Cu(salen)\\/Y and Fe(salen)\\/Y or their physical mixtures in

Binbin Fan; Hongyu Li; Weibin Fan; Chun Jin; Ruifeng Li

2008-01-01

83

Effect of CaO Addition on Iron Recovery from Copper Smelting Slags by Solid Carbon  

NASA Astrophysics Data System (ADS)

We investigated the effect of flux (lime) addition on the reduction behavior of iron oxide in copper slag by solid carbon at 1773 K (1500 °C). In particular, we quantified the recovery of iron by performing typical kinetic analysis and considering slag foaming, which is strongly affected by the thermophysical properties of slags. The iron oxide in the copper slag was consistently reduced by solid carbon over time. In the kinetic analysis, we determined mass transfer coefficients with and without considering slag foaming using a gas holdup factor. The mass transfer of FeO was not significantly changed by CaO addition when slag foaming was ignored, whereas the mass transfer of FeO when slag foaming was considered was at a minimum in the 20 mass pct CaO system. Iron recovery, defined as the ratio of the amount of iron clearly transferred to the base metal ingot to the initial amount of iron in the slag phase before reduction, was maximal (about 90 pct) in the 20 mass pct CaO system. Various types of solid compounds, including Mg2SiO4 and Ca2SiO4, were precipitated in slags during the FeO reduction process, and these compounds strongly affected the reduction kinetics of FeO as well as iron recovery. Iron recovery was the greatest in the 20 mass pct CaO system because no solid compounds formed in this system, resulting in a highly fluid slag. This fluid slag allowed iron droplets to fall rapidly with high terminal velocity to the bottom of the crucible. A linear relationship between the mass transfer coefficient of FeO considering slag foaming and foam stability was obtained, from which we concluded that the mass transfer of FeO in slag was effectively promoted not only by gas evolution due to reduction reactions but also by foamy slag containing solid compounds. However, the reduced iron droplets were finely dispersed in foamy and viscous slags, making actual iron recovery a challenge.

Heo, Jung Ho; Kim, Byung-Su; Park, Joo Hyun

2013-12-01

84

A chemical potentiator of copper-accumulation used to investigate the iron-regulons of Saccharomyces cerevisiae  

PubMed Central

The extreme resistance of Saccharomyces cerevisiae to copper is overcome by 2-(6-benzyl-2-pyridyl)quinazoline (BPQ), providing a chemical-biology tool which has been exploited in two lines of discovery. First, BPQ is shown to form a red (BPQ)2Cu(I) complex and promote Ctr1-independent copper-accumulation in whole cells and in mitochondria isolated from treated cells. Multiple phenotypes, including loss of aconitase activity, are consistent with copper-BPQ mediated damage to mitochondrial iron–sulphur clusters. Thus, a biochemical basis of copper-toxicity in S. cerevisiae is analogous to other organisms. Second, iron regulons controlled by Aft1/2, Cth2 and Yap5 that respond to mitochondrial iron–sulphur cluster status are modulated by copper-BPQ causing iron hyper-accumulation via upregulated iron-import. Comparison of copper-BPQ treated, untreated and copper-only treated wild-type and fra2? by RNA-seq has uncovered a new candidate Aft1 target-gene (LSO1) and paralogous non-target (LSO2), plus nine putative Cth2 target-transcripts. Two lines of evidence confirm that Fra2 dominates basal repression of the Aft1/2 regulons in iron-replete cultures. Fra2-independent control of these regulons is also observed but CTH2 itself appears to be atypically Fra2-dependent. However, control of Cth2-target transcripts which is independent of CTH2 transcript abundance or of Fra2, is also quantified. Use of copper-BPQ supports a substantial contribution of metabolite repression to iron-regulation. PMID:24895027

Foster, Andrew W; Dainty, Samantha J; Patterson, Carl J; Pohl, Ehmke; Blackburn, Hannah; Wilson, Clare; Hess, Corinna R; Rutherford, Julian C; Quaranta, Laura; Corran, Andy; Robinson, Nigel J

2014-01-01

85

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

86

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

PubMed Central

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

87

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

88

Investigation of Iron Metabolism in Mice Expressing a Mutant Menke’s Copper Transporting ATPase (Atp7a) Protein with Diminished Activity (Brindled; MoBr/y)  

PubMed Central

During iron deficiency, perturbations in copper homeostasis have frequently been documented. Previous studies in iron-deprived rats demonstrated that enterocyte and hepatic copper levels increase and a copper transporter (the Menkes Copper ATPase; Atp7a) is induced in the duodenal epithelium in parallel to iron transport-related genes (e.g. Dmt1, Dcytb, Fpn1). Moreover, two ferroxidase proteins involved in iron homeostasis, hephaestin expressed in enterocytes and ceruloplasmin, produced and secreted into blood by the liver, are copper-dependent enzymes. We thus aimed to test the hypothesis that Atp7a function is important for the copper-related compensatory response of the intestinal epithelium to iron deficiency. Accordingly, iron homeostasis was studied for the first time in mice expressing a mutant Atp7a protein with minimal activity (Brindled [MoBr/y]). Mutant mice were rescued by perinatal copper injections, and, after a 7–8 week recovery period, were deprived of dietary iron for 3 weeks (along with WT littermates). Adult MoBr/y mice displayed copper-deficiency anemia but had normal iron status; in contrast, iron-deprived MoBr/y mice were iron deficient and more severely anemic with partial amelioration of the copper-deficient phenotype. Intestinal iron absorption in both genotypes (WT and MoBr/y) increased ?3-fold when mice consumed a low-iron diet and ?6-fold when mice were concurrently bled. WT mice exhibited no alterations in copper homeostasis in response to iron deprivation or phlebotomy. Conversely, upregulation of iron absorption was associated with increased enterocyte and liver copper levels and serum ferroxidase (ceruloplasmin) activity in MoBr/y mice, typifying the response to iron deprivation in many mammalian species. We thus speculate that a copper threshold exists that is necessary to allow appropriate regulate of iron absorption. In summary, MoBr/y mice were able to adequately regulate iron absorption, but unlike in WT mice, concurrent increases in enterocyte and liver copper levels and serum ferroxidase activity may have contributed to maintenance of iron homeostasis. PMID:23776592

Gulec, Sukru; Collins, James F.

2013-01-01

89

Iron and Copper Act Synergistically To Delay Anaerobic Growth of Bacteria  

PubMed Central

Transition metals are known to cause toxic effects through their interaction with oxygen, but toxicity under anoxic conditions is poorly understood. Here we investigated the effects of iron (Fe) and copper (Cu) on the anaerobic growth and gene expression of the purple phototrophic bacterium Rhodopseudomonas palustris TIE-1. We found that Fe(II) and Cu(II) act synergistically to delay anaerobic growth at environmentally relevant metal concentrations. Cu(I) and Cu(II) had similar effects both alone and in the presence of ascorbate, a Cu(II) reductant, indicating that reduction of Cu(II) to Cu(I) by Fe(II) is not sufficient to explain the growth inhibition. Addition of Cu(II) increased the toxicity of Co(II) and Ni(II); in contrast, Ni(II) toxicity was diminished in the presence of Fe(II). The synergistic anaerobic toxicity of Fe(II) and Cu(II) was also observed for Escherichia coli MG1655, Shewanella oneidensis MR-1, and Rhodobacter capsulatus SB1003. Gene expression analyses for R. palustris identified three regulatory genes that respond to Cu(II) and not to Fe(II): homologs of cueR and cusR, two known proteobacterial copper homeostasis regulators, and csoR, a copper regulator recently identified in Mycobacterium tuberculosis. Two P-type ATPase efflux pumps, along with an FoF1 ATP synthase, were also upregulated by Cu(II) but not by Fe(II). An Escherichia coli mutant deficient in copA, cus, and cueO showed a smaller synergistic effect, indicating that iron might interfere with one or more of the copper homeostasis systems. Our results suggest that interactive effects of transition metals on microbial physiology may be widespread under anoxic conditions, although the molecular mechanisms remain to be more fully elucidated. PMID:23563938

Bird, Lina J.; Coleman, Maureen L.

2013-01-01

90

Iron and copper act synergistically to delay anaerobic growth of bacteria.  

PubMed

Transition metals are known to cause toxic effects through their interaction with oxygen, but toxicity under anoxic conditions is poorly understood. Here we investigated the effects of iron (Fe) and copper (Cu) on the anaerobic growth and gene expression of the purple phototrophic bacterium Rhodopseudomonas palustris TIE-1. We found that Fe(II) and Cu(II) act synergistically to delay anaerobic growth at environmentally relevant metal concentrations. Cu(I) and Cu(II) had similar effects both alone and in the presence of ascorbate, a Cu(II) reductant, indicating that reduction of Cu(II) to Cu(I) by Fe(II) is not sufficient to explain the growth inhibition. Addition of Cu(II) increased the toxicity of Co(II) and Ni(II); in contrast, Ni(II) toxicity was diminished in the presence of Fe(II). The synergistic anaerobic toxicity of Fe(II) and Cu(II) was also observed for Escherichia coli MG1655, Shewanella oneidensis MR-1, and Rhodobacter capsulatus SB1003. Gene expression analyses for R. palustris identified three regulatory genes that respond to Cu(II) and not to Fe(II): homologs of cueR and cusR, two known proteobacterial copper homeostasis regulators, and csoR, a copper regulator recently identified in Mycobacterium tuberculosis. Two P-type ATPase efflux pumps, along with an F(o)F(1) ATP synthase, were also upregulated by Cu(II) but not by Fe(II). An Escherichia coli mutant deficient in copA, cus, and cueO showed a smaller synergistic effect, indicating that iron might interfere with one or more of the copper homeostasis systems. Our results suggest that interactive effects of transition metals on microbial physiology may be widespread under anoxic conditions, although the molecular mechanisms remain to be more fully elucidated. PMID:23563938

Bird, Lina J; Coleman, Maureen L; Newman, Dianne K

2013-06-01

91

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. PMID:24159298

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

2013-01-01

92

Seasonal changes of zinc, copper, and iron in gilthead sea bream ( Sparus aurata ) fed fortified diets  

Microsoft Academic Search

Four groups of gilthead sea bream (Sparus aurata) were fed diets with additional metal contents: a basal diet (diet A) contained Zn at 60.9 ± 1.9 mg\\/kg diet, Cu at 3.9 ±\\u000a 0.9 mg\\/kg diet, and Fe at 138.3 ± 6.8 mg\\/kg diet; the other diets were supplemented with copper (20 mg\\/kg, diet B), iron (100\\u000a mg\\/kg, diet C), or

Emilio Carpeme; Rossella Serra; Maurizio Manera; Gloria Isani

1999-01-01

93

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

94

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. 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

95

Rapid Size- Controlled Synthesis of Dextran-Coated, Copper-Doped Iron Oxide Nanoparticles  

NASA Astrophysics Data System (ADS)

Development of dual modality probes enabled for magnetic resonance imaging (MRI) and positron emission tomography (PET) has been on the rise in recent years due to the potential for these probes to facilitate combining the complementary high resolution of MRI and the high sensitivity of PET. The efficient synthesis of multimodal probes that include the radiolabels for PET can be hindered due to prolonged reaction times during radioisotope incorporation, and the resulting decay of the radiolabel. Along with a time-efficient synthesis, one also needs an optimal synthesis that yields products in a desirable size range (between 20-100 nm) to increase blood retention time. In this work, we describe a novel, rapid, microwave-based synthesis of dextran-coated iron oxide nanoparticles doped with copper (DIO/Cu). Traditional methods for synthesizing dextran-coated iron oxide particles require refluxing for 2 hours and result in approximately 50 nm particles. We demonstrate that microwave synthesis can produce 50 nm nanoparticles in 5 minutes of heating. We discuss the various parameters used in the microwave synthesis protocol to vary the size distribution of DIO/Cu, and demonstrate the successful incorporation of copper into these particles with the aim of future use for rapid 64Cu incorporation.

Wong, Ray M.

2011-12-01

96

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

97

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

98

Effects of substituting mercury for yttrium, barium and copper on the superconducting transition temperature of YBa 2 Cu 3 O ?  

Microsoft Academic Search

Several superconducting oxide samples such as YBa2Cu3Od (denoted AO), Y1-xHgxBa2Cu3Od (x=0.5–0.8, Al), YBa2-xHgxCu3Od (x=0.3–1.5, A2) and YBa2Cu3-xHgxOd (x=0.5, A3) were prepared by mixing Y203, BaCO3, copper acetate (instead of CuO) and HgO. The superconducting transition temperatures,Tc, in all the mercury-doped samples were found to be more than 90 K, with the highestTc = 100 K observed in A2. Results of

A. K. Chakraborty; K. Bose; G. De; K. K. Som; B. K. Chaudhuri

1994-01-01

99

Iron, copper, and nickel behavior in buffered, neutral aluminum chloride:1-methyl-3-ethylimidazolium chloride molten salt  

Microsoft Academic Search

Iron, copper, and nickel electrodes were examined as possible metal\\/metal(II) chloride cathodes for the room temperature sodium\\/metal chloride battery in a molten salt composed of sodium chloride (NaCl), aluminum chloride (AlClâ), and 1-methyl-3-ethylimidazolium chloride (MEIC). The iron electrode was investigated in basic, neutral-like, and acidic MEIC:AlClâ melts. The solubility and the kinetics of the reduction of Fe(II) was a function

Stephen Pye; J. Winnick; P. A. Kohl

1997-01-01

100

Synthesis of Barium Hexaferrite/iron Oxides Magnetic Nano-Composites via High Energy Ball Milling and Subsequent Heat Treatment  

NASA Astrophysics Data System (ADS)

Barium hexaferrite (BaFe12O19) is a hard magnetic ceramic with superior magnetic properties and in powder form has potential for application in high density recording media. In this research a mechano-chemical approach was applied in order to achieve a nano-structured magnetic composite. Graphite was used to reduce barium hexaferrite in mechanical milling medium under argon atmosphere. Milling was carried out with a ball to powder mass ratio of 35 and rotation speed of 300 rpm. Effects of milling time on phase composition and morphology of the samples were evaluated by XRD and SEM techniques, respectively. XRD results revealed that after 20 hours of milling, nano-composite of BaFe12O19/Fe3O4/Fe2O3 was obtained. By extending the milling time to 40 hours, FeO was detected as the dominant crystalline phase with crystallite size of 22 nm. Composite of Fe/FeO/Fe3O4 was synthesized by controlled heat treatment of the 40 hours milled sample. SEM results revealed that particle size in the aforementioned heat treated composite sample reached to about 89 nm and the morphology of the samples changed slightly.

Molaei, M. J.; Ataie, A.; Raygan, S.

101

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

102

Micronutrient status in female university students: iron, zinc, copper, selenium, vitamin B12 and folate.  

PubMed

Young women are at an increased risk of micronutrient deficiencies, particularly due to higher micronutrient requirements during childbearing years and multiple food group avoidances. The objective of this study was to investigate biomarkers of particular micronutrients in apparently healthy young women. Female students (n = 308; age range 18-35 year; Body Mass Index 21.5 ± 2.8 kg/m2; mean ± SD) were recruited to participate in a cross-sectional study. Blood samples were obtained from participants in the fasted state and analysed for biomarkers of iron status, vitamin B12, folate, homocysteine, selenium, zinc, and copper. The results show iron deficiency anaemia, unspecified anaemia, and hypoferritinemia in 3%, 7% and 33.9% of participants, respectively. Low vitamin B12 concentrations (<120 pmol/L) were found in 11.3% of participants, while 4.7% showed sub-clinical deficiency based on serum methylmalonic acid concentrations >0.34 ?mol/L. Folate concentrations below the reference range were observed in 1.7% (serum) or 1% (erythrocytes) of participants, and 99.7% of the participant had erythrocyte-folate concentrations >300 nmol/L. Serum zinc concentrations <10.7 ?mol/L were observed in 2% of participants. Serum copper and selenium concentrations were below the reference range in 23% and 11% of participants, respectively. Micronutrient deficiencies including iron and vitamin B12, and apparent excess of folate are present in educated Australian female students of childbearing age, including those studying nutrition. The effects of dietary behaviours and food choices on markers of micronutrient status require further investigation. PMID:25401503

Fayet-Moore, Flavia; Petocz, Peter; Samman, Samir

2014-11-01

103

Haemolysis and Perturbations in the Systemic Iron Metabolism of Suckling, Copper-Deficient Mosaic Mutant Mice – An Animal Model of Menkes Disease  

PubMed Central

The biological interaction between copper and iron is best exemplified by the decreased activity of multicopper ferroxidases under conditions of copper deficiency that limits the availability of iron for erythropoiesis. However, little is known about how copper deficiency affects iron homeostasis through alteration of the activity of other copper-containing proteins, not directly connected with iron metabolism, such as superoxide dismutase 1 (SOD1). This antioxidant enzyme scavenges the superoxide anion, a reactive oxygen species contributing to the toxicity of iron via the Fenton reaction. Here, we analyzed changes in the systemic iron metabolism using an animal model of Menkes disease: copper-deficient mosaic mutant mice with dysfunction of the ATP7A copper transporter. We found that the erythrocytes of these mutants are copper-deficient, display decreased SOD1 activity/expression and have cell membrane abnormalities. In consequence, the mosaic mice show evidence of haemolysis accompanied by haptoglobin-dependent elimination of haemoglobin (Hb) from the circulation, as well as the induction of haem oxygenase 1 (HO1) in the liver and kidney. Moreover, the hepcidin-ferroportin regulatory axis is strongly affected in mosaic mice. These findings indicate that haemolysis is an additional pathogenic factor in a mouse model of Menkes diseases and provides evidence of a new indirect connection between copper deficiency and iron metabolism. PMID:25247420

Lenartowicz, Ma?gorzata; Starzy?ski, Rafa? R.; Krzeptowski, Wojciech; Grzmil, Pawe?; Bednarz, Aleksandra; Ogórek, Mateusz; Pierzcha?a, Olga; Staro?, Robert; Gajowiak, Anna; Lipi?ski, Pawe?

2014-01-01

104

The effect of iron and copper as an essential nutrient on mitochondrial electron transport system and lipid peroxidation in Trichoderma harzianum.  

PubMed

Iron and copper are essential nutrients for all living organisms as cofactors of many enzymes and play important roles in electron transport system (ETS) enzymes which have heme and iron-sulfur centers. In the present study, ETS enzymes, namely, succinate dehydrogenase (SDH) and cytochrome c oxidase (COX), activities as well as adenine nucleotides and lipid peroxidation (LPO) levels of eukaryotic model Trichoderma harzianum grown in varied concentrations of iron (0-20 mg/l) and copper (0-25 mg/l) mediums have been examined. SDH and COX activities increased up to 10 mg/l of iron. COX and SDH activities increased significantly up to 15 and 1 mg/l of copper, respectively. ATP and ADP levels showed a positive correlation with SDH activity with respect to iron-copper concentrations. The trends of AMP were similar with those of ATP and ADP for iron concentrations, while AMP levels elevated until 5 mg/l of copper. As an indicative marker of membrane damage, LPO levels increased with iron and copper concentration. In conclusion, iron and copper concentrations are of critical importance on activities of the ETS enzymes besides adenine nucleotides and LPO levels by maintenance of this metal homeostasis. PMID:23716140

Tavsan, Zehra; Ayar Kayali, Hulya

2013-08-01

105

pH-Dependent reactivity of oxidants formed by iron and copper-catalyzed decomposition of hydrogen peroxide.  

PubMed

The decomposition of hydrogen peroxide catalyzed by iron and copper leads to the generation of reactive oxidants capable of oxidizing various organic compounds. However, the specific nature of the reactive oxidants is still unclear, with evidence suggesting the production of hydroxyl radical or high-valent metal species. To identify the reactive species in the Fenton system, the oxidation of a series of different compounds (phenol, benzoic acid, methanol, Reactive Black 5 and arsenite) was studied for iron- and copper-catalyzed reactions at varying pH values. At lower pH values, more reactive oxidants appear to be formed in both iron and copper-catalyzed systems. The aromatic compounds, phenol and benzoic acid, were not oxidized under neutral or alkaline pH conditions, whereas methanol, Reactive Black 5, and arsenite were oxidized to a different degree, depending on the catalytic system. The oxidants responsible for the oxidation of compounds at neutral and alkaline pH values are likely to be high-valent metal complexes of iron and copper (i.e., ferryl and cupryl ions). PMID:23433935

Lee, Hongshin; Lee, Hye-Jin; Sedlak, David L; Lee, Changha

2013-07-01

106

Transcriptional regulation of copper metabolism genes in the liver of fetal and neonatal control and iron-deficient rats.  

PubMed

Copper and iron metabolism have been known to interact for many years. We have previously shown, during pregnancy, that copper levels in the maternal liver rise as a consequence of iron deficiency, but that levels in the fetal liver decrease. In this paper, we measure expression of genes involved in copper metabolism in fetal and postnatal liver, to test whether alterations can explain this observation. Additionally, we study the extent to which gene expression changes in the latter stages of pregnancy and in the perinatal period. Ctr1 expression levels dropped to term, rising again thereafter. There was no difference in gene expression between control and iron deficient animals. Atox1 expression remained approximately stable until term, and then there was a rise to a maximum at about Day 8. Atp7a expression levels remained constant, except for a brief drop at term. Atp7b levels, in contrast, decreased from a maximum early in gestation to low levels in the term and post-natal livers. Ceruloplasmin expression appeared to be diametrically opposite to Atp7b. The other two metallochaperones showed the same pattern of expression as Atox1, with a decrease to term, a rise at Day 1, or a rise after birth followed by a brief decrease at about Day 3. None of the genes were significantly affected by iron deficiency, suggesting that changes in expression cannot explain the altered copper levels in the fetal and neonatal liver. PMID:25349135

Lenartowicz, Malgorzata; Kennedy, Christine; Hayes, Helen; McArdle, Harry J

2015-02-01

107

Adventiously-bound redox active iron and copper are at the center of oxidative damage in Alzheimer disease  

Microsoft Academic Search

Central to oxidative damage in Alzheimer disease is the production of metal-catalyzed hydroxyl radicals that damage every category of macromolecule. Studies on redox-competent copper and iron indicate that redox activity in Alzheimer disease resides exclusively within the cytosol of vulnerable neurons and that chelation with deferoxamine or DTPA removes this activity. We have also found that while proteins that accumulate

George Perry; Marta A. Taddeo; Robert B. Petersen; Rudy J. Castellani; Peggy L. R. Harris; Sandra L. Siedlak; Adam D. Cash; Quan Liu; Akohiko Nunomura; Craig S. Atwood; Mark A. Smith

2003-01-01

108

Creation of ribbon substrates with a sharp cube texture of copper and copper-nickel alloys additionally alloyed with iron and chromium  

NASA Astrophysics Data System (ADS)

The possibility of obtaining a perfect cube texture in thin ribbon made of binary copper-nickel alloys opens the possibility of using them as substrates in the technology of second-generation HTSC cables. The possibility of production of multicomponent alloys based on a binary Cu-30% Ni alloy additionally alloyed with elements (such as iron or chromium) that strengthen the fcc matrix has been shown. Optimum regimes of annealing have been determined, which make it possible to obtain a perfect biaxial texture with the content of cube grains {001}<100> exceeding 97% in Cu- M and Cu-30Ni- M ( M = Fe or Cr) alloys. In the tapes made of copper alloys with iron or chromium, the precipitation of disperse particles occurs in the process of cooling after recrystallization annealing, which improves the mechanical properties of the substrate. The estimation of the mechanical properties of the textured ribbons of binary and ternary copper alloys demonstrates a yield stress higher than that of the ribbons of pure copper by a factor of 2.5-4.5.

Schastlivtsev, V. M.; Khlebnikova, Yu. V.; Rodionov, D. P.; Gervas'eva, I. V.; Suaridze, T. R.

2014-12-01

109

Correlations between lead, cadmium, copper, zinc, and iron concentrations in frozen tuna fish  

SciTech Connect

The presence of metallic pollutants in marine ecosystems has promoted wide research plans in order to evaluate pollution levels in marine organisms. However, little is known concerning environmental and physiological processes that regulate the concentration of trace metals in marine organisms. Even though the toxicity of lead and cadmium is well established, copper, zinc and iron are considered as essential elements for mammals. Little is known about heavy metals, other than mercury, concentrations in fresh and frozen tuna fish. Fifty samples obtained at the entrance of a canning factory in Santa Cruz de Tenerife (Canary Islands), were analyzed by atomic absorption spectrophotometry. Results were treated by applying the Statistical Package for the Social Sciences compiled and linked in the software of a Digital VAX/VMS 11/780 computer.

Galindo, L.; Hardisson, A.; Montelongo, F.G.

1986-04-01

110

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. PMID:2420582

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

1985-01-01

111

Photometric and spectrochemical determination of gold in iron pyrites, copper and lead concentrates.  

PubMed

A photometric and a spectrochemical method have been developed for determining gold in iron pyrites, copper and lead concentrates. In both, the sample is dissolved and gold is extracted from 1M hydrochloric add solution with a mixture of ethyl methyl ketone and chloroform (1:1). Gold was determined photometrically with N,N'-tetramethyl-o-tolidine. Conditions have been found for satisfactorily sensitive and reproducible spectral determination of gold. For this purpose the effect of various collectors and buffers on the evaporation curves of gold has been studied, as well as excitation conditions, form of the electrodes, optimum slit-width, and photographic variables. The sensitivity and precision of both methods have been evaluated. PMID:18960389

Jordanov, N; Mareva, S; Krasnobaeva, N; Nedyalkova, N

1968-09-01

112

SOURCE ASSESSMENT: MAJOR BARIUM CHEMICALS  

EPA Science Inventory

This report summarizes data on air emissions from the production of major barium chemicals. Compounds studied include barium sulfide, barium carbonate, barium chloride, barium hydroxide, and barium sulfate. In order to evaluate potential environmental effects the source severity,...

113

Predicting copper-, iron-, and zinc-binding proteins in pathogenic species of the Paracoccidioides genus  

PubMed Central

Approximately one-third of all proteins have been estimated to contain at least one metal cofactor, and these proteins are referred to as metalloproteins. These represent one of the most diverse classes of proteins, containing metal ions that bind to specific sites to perform catalytic, regulatory and structural functions. Bioinformatic tools have been developed to predict metalloproteins encoded by an organism based only on its genome sequence. Its function and the type of metal binder can also be predicted via a bioinformatics approach. Paracoccidioides complex includes termodimorphic pathogenic fungi that are found as saprobic mycelia in the environment and as yeast, the parasitic form, in host tissues. They are the etiologic agents of Paracoccidioidomycosis, a prevalent systemic mycosis in Latin America. Many metalloproteins are important for the virulence of several pathogenic microorganisms. Accordingly, the present work aimed to predict the copper, iron and zinc proteins encoded by the genomes of three phylogenetic species of Paracoccidioides (Pb01, Pb03, and Pb18). The metalloproteins were identified using bioinformatics approaches based on structure, annotation and domains. Cu-, Fe-, and Zn-binding proteins represent 7% of the total proteins encoded by Paracoccidioides spp. genomes. Zinc proteins were the most abundant metalloproteins, representing 5.7% of the fungus proteome, whereas copper and iron proteins represent 0.3 and 1.2%, respectively. Functional classification revealed that metalloproteins are related to many cellular processes. Furthermore, it was observed that many of these metalloproteins serve as virulence factors in the biology of the fungus. Thus, it is concluded that the Cu, Fe, and Zn metalloproteomes of the Paracoccidioides spp. are of the utmost importance for the biology and virulence of these particular human pathogens.

Tristão, Gabriel B.; Assunção, Leandro do Prado; dos Santos, Luiz Paulo A.; Borges, Clayton L.; Silva-Bailão, Mirelle Garcia; Soares, Célia M. de Almeida; Cavallaro, Gabriele; Bailão, Alexandre M.

2015-01-01

114

NORMAL:SUPERCONDUCTOR Point Contact Spectroscopy of Niobium, NEODYMIUM(1.85) CERIUM(0.15) Copper OXYGEN(4 - and Yttrium BARIUM(2) COPPER(3) OXYGEN(7-DELTA  

NASA Astrophysics Data System (ADS)

Point contacts are electrical contacts with dimensions smaller than the characteristic dimension associated with charge transport in the conducting material near the contact. In normal materials this characteristic dimension is the mean free path of the charge carriers (electrons or holes) and in a superconductor the characteristic dimension is the superconducting coherence length. In this limit, the transfer of charge through the contact is ballistic rather than diffusive. That is, the charge does not move through the contact with an average "drift" velocity, as in a bulk conductor, since the average distance between collisions is on the order of the contact size. As might be expected, the resistance of a point contact varies with changes in the scattering probability for charge carriers. By measuring nonlinearities in the voltage vs. current curves (V-I curves) of point contacts, information about the scattering mechanisms in conductors can be obtained. In this study, the differential resistance (dV/dI) vs. V curves of point contacts formed between normal metal wires and superconducting wedges were measured as a function of temperature. On elemental metal superconductor (niobium) and two high transition temperature superconductors (Nd _{1.85}Ce_ {0.15}CuO_{4-delta } and rm YBa_2 Cu_3 O_{7-delta}) were used. The results for niobium contacts with silver, aluminum and copper closely matched the predictions of a recent theory describing electrical conduction through normal:superconducting point contacts (1). The results for the differential resistance (dV/dI) at zero voltage bias for Ag:Nd_ {1.85}Ce_{0.15} CuO_{4-delta} point contacts also matched this theory, but other aspects of the dV/dI vs. V curves differed significantly from the theory. The dV/dI vs. V curves for Ag:rm YBa_2 Cu_3 O_{7-delta} ) point contacts were dominated by critical current effects and did not resemble the predicted form from the theory. Reference. (1) G. E. Blonder, M. Tinkham, and T. M. Klapwijk, Phys. Rev. B 25, 4515 (1982).

Reinertson, Randal C.

1991-02-01

115

Regulation of brain iron and copper homeostasis by brain barrier systems: implication in neurodegenerative diseases.  

PubMed

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. PMID:22115751

Zheng, Wei; Monnot, Andrew D

2012-02-01

116

Cadmium, copper, iron, and zinc concentrations in kidneys of grey wolves, Canis lupus, from Alaska, Idaho, Montana (USA) and the Northwest Territories (Canada).  

PubMed

Cadmium, copper, iron, and zinc levels were measured in the kidneys of 115 grey wolves (Canis lupus) from Idaho, Montana and Alaska (United States), and from the Northwest Territories (Canada). No significant differences in the levels of iron or copper were observed between locations, but wolf kidneys from more northern locations had significantly higher cadmium levels (Alaska > Northwest Territories > Montana ? Idaho), and wolves from Alaska showed significantly higher zinc than other locations. Additionally, female wolves in Alaska had higher iron levels than males, and adult wolves in Montana had higher copper levels than subadults. PMID:20972865

Hoffmann, S R; Blunck, S A; Petersen, K N; Jones, E M; Koval, J C; Misek, R; Frick, J A; Cluff, H D; Sime, C A; McNay, M; Beckman, K B; Atkinson, M W; Drew, M; Collinge, M D; Bangs, E E; Harper, R G

2010-11-01

117

Copper(I)- and copper(0)-promoted homocoupling and homocoupling-hydrodehalogenation reactions of dihalogenoclathrochelate precursors for C-C conjugated iron(II) bis-cage complexes.  

PubMed

Iron(II) dibromo- and diiodoclathrochelates undergo copper(I)-promoted reductive homocoupling in HMPA at 70-80 °C leading to C-C conjugated dibromo- and diiodo-bis-clathrochelates in high yields. Under the same conditions, their dichloroclathrochelate analog does not undergo the same homocoupling reaction, so the target dichloro-bis-cage product was obtained in high yield via dimerization of its heterodihalogenide iodochloromonomacrobicyclic precursor. The use of NMP as a solvent at 120-140 °C gave the mixture of bis-clathrochelates resulting from a tandem homocoupling-hydrodehalogenation reaction: the initial acetonitrile copper(I) solvato-complex at a high temperature underwent re-solvatation and disproportionation leading to Cu(II) ions and nano-copper, which promoted the hydrodehalogenation process even at room temperature. The most probable pathway of this reaction in situ includes hydrodehalogenation of the already formed dihalogeno-bis-clathrochelate via the formation of reduced anion radical intermediates. As a result, chemical transformations of the iron(II) dihalogenoclathrochelates in the presence of an acetonitrile copper(I) solvato-complex were found to depend both on the nature of halogen atoms in their ribbed chelate fragments and on reaction conditions (i.e. solvent and temperature). The C-C conjugated iron(II) dihalogeno-bis-clathrochelates easily undergo nucleophilic substitution with various N,S-nucleophiles giving ribbed-functionalized bis-cage species. These iron(II) complexes were characterized by elemental analysis, MALDI-TOF mass spectrometry, IR, UV-Vis, (1)H and (13)C NMR spectroscopy, and by X-ray diffraction; their electrochemical properties were studied by cyclic voltammetry. The isomeric shift values in (57)Fe Mössbauer spectra of such cage compounds allowed identifying them as low-spin iron(II) complexes, while those of the quadrupole splitting are the evidence for a significant TP distortion of their FeN6-coordination polyhedra. As follows from CV data, the C-C conjugated iron(II) bis-clathrochelates undergo stepwise electrochemical reduction and oxidation giving mixed-valence Fe(II)Fe(I) and Fe(II)Fe(III) bis-cage intermediates. PMID:25056255

Varzatskii, Oleg A; Shul'ga, Sergey V; Belov, Alexander S; Novikov, Valentin V; Dolganov, Alexander V; Vologzhanina, Anna V; Voloshin, Yan Z

2014-12-28

118

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. PMID:21833306

Silva, Mirelle Garcia; Schrank, Augusto; Bailão, Elisa Flávia L.C.; Bailão, Alexandre Melo; Borges, Clayton Luiz; Staats, Charley Christian; Parente, Juliana Alves; Pereira, Maristela; Salem-Izacc, Silvia Maria; Mendes-Giannini, Maria José Soares; Oliveira, Rosely Maria Zancopé; Silva, Lívia Kmetzsch Rosa e; Nosanchuk, Joshua D.; Vainstein, Marilene Henning; de Almeida Soares, Célia Maria

2011-01-01

119

Cadmium, Copper, Iron, and Zinc Concentrations in Kidneys of Grey Wolves, Canis lupus , from Alaska, Idaho, Montana (USA) and the Northwest Territories (Canada)  

Microsoft Academic Search

Cadmium, copper, iron, and zinc levels were measured in the kidneys of 115 grey wolves (Canis lupus) from Idaho, Montana and Alaska (United States), and from the Northwest Territories (Canada). No significant differences\\u000a in the levels of iron or copper were observed between locations, but wolf kidneys from more northern locations had significantly\\u000a higher cadmium levels (Alaska > Northwest Territories

S. R. Hoffmann; S. A. Blunck; Petersen Kelly; E. M. Jones; J. C. Koval; R. Misek; J. A. Frick; H. D. Cluff; C. A. Sime; M. McNay; K. B. Beckman; M. W. Atkinson; M. Drew; M. D. Collinge; E. E. Bangs; R. G. Harper

2010-01-01

120

Utilization of activating and masking effects by ligands for highly selective catalytic spectrophotometric determination of copper and iron in natural waters.  

PubMed

A kinetic-catalytic spectrophotometric method is proposed for the successive determination of nanogram levels of copper and iron, which is based on their catalytic effects on the oxidative coupling of p-anisidine with N,N-dimethylaniline (DMA) to form a colored compound (lambda(max)=740 nm) in the presence of hydrogen peroxide at pH 3.2. 2,9-Dimethyl-1,10-phenanthroline (neocuproine) acted as an activator for the copper catalysis, and 1,10-phenanthroline (phen) acted as an activator for the iron catalysis. The selectivity was improved in the presence of diphosphate as a masking agent. The determinable ranges were 0.16-10 ppb for copper and 1-100 ppb for iron, respectively. The relative standard deviations of copper and iron were 1.1 and 0.97% for five determinations of 10 ppb copper and 40 ppb iron. The method was successfully applied to the analyses of copper and iron in tap, well, river and pond waters. PMID:18969144

Ohno, Shinsuke; Teshima, Norio; Zhang, Heng; Sakai, Tadao

2003-08-29

121

Tribological behaviour and statistical experimental design of sintered iron-copper based composites  

NASA Astrophysics Data System (ADS)

The sintered iron-copper based composites for automotive brake pads have a complex composite composition and should have good physical, mechanical and tribological characteristics. In this paper, we obtained frictional composites by Powder Metallurgy (P/M) technique and we have characterized them by microstructural and tribological point of view. The morphology of raw powders was determined by SEM and the surfaces of obtained sintered friction materials were analyzed by ESEM, EDS elemental and compo-images analyses. One lot of samples were tested on a "pin-on-disc" type wear machine under dry sliding conditions, at applied load between 3.5 and 11.5 × 10-1 MPa and 12.5 and 16.9 m/s relative speed in braking point at constant temperature. The other lot of samples were tested on an inertial test stand according to a methodology simulating the real conditions of dry friction, at a contact pressure of 2.5-3 MPa, at 300-1200 rpm. The most important characteristics required for sintered friction materials are high and stable friction coefficient during breaking and also, for high durability in service, must have: low wear, high corrosion resistance, high thermal conductivity, mechanical resistance and thermal stability at elevated temperature. Because of the tribological characteristics importance (wear rate and friction coefficient) of sintered iron-copper based composites, we predicted the tribological behaviour through statistical analysis. For the first lot of samples, the response variables Yi (represented by the wear rate and friction coefficient) have been correlated with x1 and x2 (the code value of applied load and relative speed in braking points, respectively) using a linear factorial design approach. We obtained brake friction materials with improved wear resistance characteristics and high and stable friction coefficients. It has been shown, through experimental data and obtained linear regression equations, that the sintered composites wear rate increases with increasing applied load and relative speed, but in the same conditions, the frictional coefficients slowly decrease.

Popescu, Ileana Nicoleta; Ghi??, Constantin; Bratu, Vasile; Palacios Navarro, Guillermo

2013-11-01

122

Molecular bases of copper and iron deficiency-associated dyslipidemia: a microarray analysis of the rat intestinal transcriptome  

Microsoft Academic Search

As essential cofactor in many proteins and redox enzymes, copper and iron are involved in a wide range of biological processes.\\u000a Mild dietary deficiency of metals represents an underestimated problem for human health, because it does not cause clear signs\\u000a and clinical symptoms, but it is associated to long-term deleterious effects in cardiovascular system and alterations in lipid\\u000a metabolism. The

Alessandra Tosco; Bianca Fontanella; Rosa Danise; Luigi Cicatiello; Olì M. V. Grober; Maria Ravo; Alessandro Weisz; Liberato Marzullo

2010-01-01

123

Catalytic activity and magnetic properties of barium hexaferrite prepared from barite ore  

Microsoft Academic Search

Barium hexaferrite (BaFe12O19) has traditionally been used in permanent magnets and more recently used for high density magnetic recording. The classical ceramic method for the preparation of barium hexaferrite consists of firing mixture of chemical grade iron oxide and barium carbonate at high temperature. In this paper a mixture of chemical grade hematite, barium oxide and predetermined mixtures of iron

M. M. Hessien; M. H. Khedr

2007-01-01

124

Iron, copper, and nickel behavior in buffered, neutral aluminum chloride:1-methyl-3-ethylimidazolium chloride molten salt  

SciTech Connect

Iron, copper, and nickel electrodes were examined as possible metal/metal(II) chloride cathodes for the room temperature sodium/metal chloride battery in a molten salt composed of sodium chloride (NaCl), aluminum chloride (AlCl{sub 3}), and 1-methyl-3-ethylimidazolium chloride (MEIC). The iron electrode was investigated in basic, neutral-like, and acidic MEIC:AlCl{sub 3} melts. The solubility and the kinetics of the reduction of Fe(II) was a function of acidity. In the basic melt, the FeCl{sub 2} was soluble; however, its reduction was not observed due to slow kinetics. In the neutral-like and acidic melts, the quasi-reversible reduction of Fe(II) to Fe(0) was observed. The redox potential of copper was approximately 1 V more positive of iron; however, the oxidized copper was soluble in the neutral-like melt, making it unacceptable without a separator. The oxidized and reduced forms of nickel were insoluble and the redox potential was 2.5 V positive of Na/Na{sup +}. The nickel electrode supported a charge density of 3.5 mC/cm{sup 2} at room temperature, suggesting that a high-surface-area electrode would be needed in a practical device.

Pye, S.; Winnick, J.; Kohl, P.A. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Chemical Engineering

1997-06-01

125

Barium Enema Examination  

MedlinePLUS

Barium Enema Examination What you need to know about… A barium enema examination dem- onstrates your large bowel (colon). ... a diagnostically useful image. Prior to performing your barium enema examination, the radiographer will give you a ...

126

Assessing Plasma Levels of Selenium, Copper, Iron and Zinc in Patients of Parkinson’s Disease  

PubMed Central

Trace elements have been recognized to play an important role in the development of Parkinson’s disease (PD). However, it is difficult to precisely identify the relationship between these elements and the progression of PD because of an insufficient number of patients. In this study, quantifications of selenium (Se), copper (Cu), iron (Fe) and zinc (Zn) by atomic absorption spectrophotometry were performed in plasma from 238 PD patients and 302 controls recruited from eastern China, which is so far the largest cohort of PD patients and controls for measuring plasma levels of these elements. We found that plasma Se and Fe concentrations were significantly increased whereas Cu and Zn concentrations decreased in PD patients as compared with controls. Meanwhile, these four elements displayed differential changes with regard to age. Linear and logistic regression analyses revealed that both Fe and Zn were negatively correlated with age in PD patients. Association analysis suggests that lower plasma Se and Fe levels may reduce the risk for PD, whereas lower plasma Zn is probably a PD risk factor. Finally, a model was generated to predict PD patients based on the plasma concentrations of these four trace elements as well as other features such as sex and age, which achieved an accuracy of 80.97±1.34% using 10-fold cross-validation. In summary, our data provide new insights into the roles of Se, Cu, Fe and Zn in PD progression. PMID:24340079

Cheng, Xing; Wang, Jian-Yong; Hu, Bei-Lei; Zhang, Yan; Zhang, Xiong; Zhu, Jian-Hong

2013-01-01

127

The membrane-associated form of methane mono-oxygenase from Methylococcus capsulatus (Bath) is a copper/iron protein.  

PubMed Central

A protocol has been developed which permits the purification of a membrane-associated methane-oxidizing complex from Methylococcus capsulatus (Bath). This complex has approximately 5 fold higher specific activity than any purified particulate methane mono-oxygenase (pMMO) previously reported from M. capsulatus (Bath). This efficiently functioning methane-oxidizing complex consists of the pMMO hydroxylase (pMMOH) and an unidentified component we have assigned as a potential pMMO reductase (pMMOR). The complex was isolated by solubilizing intracytoplasmic membrane preparations containing the high yields of active membrane-bound pMMO (pMMO(m)), using the non-ionic detergent dodecyl-beta-D-maltoside, to yield solubilized enzyme (pMMO(s)). Further purification gave rise to an active complex (pMMO(c)) that could be resolved (at low levels) by ion-exchange chromatography into two components, the pMMOH (47, 27 and 24 kDa subunits) and the pMMOR (63 and 8 kDa subunits). The purified complex contains two copper atoms and one non-haem iron atom/mol of enzyme. EPR spectra of preparations grown with (63)Cu indicated that the copper ion interacted with three or four nitrogenic ligands. These EPR data, in conjunction with other experimental results, including the oxidation by ferricyanide, EDTA treatment to remove copper and re-addition of copper to the depleted protein, verified the essential role of copper in enzyme catalysis and indicated the implausibility of copper existing as a trinuclear cluster. The EPR measurements also demonstrated the presence of a tightly bound mononuclear Fe(3+) ion in an octahedral environment that may well be exchange-coupled to another paramagnetic species. PMID:12379148

Basu, Piku; Katterle, Bettina; Andersson, K Kristoffer; Dalton, Howard

2003-01-01

128

Characterization of Precious Metal Resources in Copper Slag and Their Implications in Beneficiation  

NASA Astrophysics Data System (ADS)

Studies have been carried out on precious metal association, on a typical Indian copper slag sample using SEM-EDS. The studies revealed the presence of platinum as well as gold, reported here for the first time, in the copper metal as well as different types of metallic sulphides phases of the copper slag. These phases are either entrapped in the silicate minerals or are present as free liberated grains within the slag sample. The platinum content varies in the range of 1.24-1.95 wt% whereas gold values range from 2.41 to 5.90 wt% in some phases. The phases of copper slag, which contain gold and platinum are present in very less quantity with respect to volume percentage. The major phases, in the copper slag are fayalite and magnetite while spinel, ulvospinel, metallic iron, calcium oxide and barium sulphide are minor phases and all these are devoid of gold or platinum.

Rao, D. S.; Angadi, S.; Reddy, P. S. R.

2015-01-01

129

Maternal iron supplementation attenuates the impact of perinatal copper deficiency but does not eliminate hypotriiodothyroninemia nor impaired sensorimotor development  

PubMed Central

Copper (Cu), iron (Fe), and iodine/thyroid hormone (TH) deficiencies disrupt brain development. Neonatal Cu deficiency causes Fe deficiency and may impact thyroidal status. One purpose of these studies was to determine the impact of improved iron status following Cu deficiency by supplementing the diet with iron. Cu deficiency was produced in pregnant Holtzman (Exp. 1) or Sprague Dawley (Exp. 2) rats using two different diets. In Exp. 2, dietary Fe content was increased from 35 to 75 mg/kg according to NRC guidelines for reproduction. Cu deficient (CuD) postnatal day 24 (P24) rats from both experiments demonstrated lower hemoglobin, serum Fe, and serum triiodothyronine (T3) concentrations. However, brain Fe was lower only in CuD P24 rats in Exp. 1. Hemoglobin and serum Fe were higher in Cu adequate (CuA) P24 rats from Exp. 2 compared to Exp. 1. Cu and TH deficient rats from Exp. 2 exhibited a similar sensorimotor functional deficit following three months of repletion. Results suggest that Cu deficiency may impact TH status independent of its impact on iron biology. Further research is needed to clarify the individual roles for Cu, Fe, and TH in brain development. PMID:21239157

Bastian, Thomas W.; Lassi, Katie C.; Anderson, Grant W.; Prohaska, Joseph R.

2012-01-01

130

Concentration of copper, iron, zinc, cadmium, lead, and nickel in boar semen and relation to the spermatozoa quality.  

PubMed

The concentration of copper, iron, zinc, cadmium, lead, and nickel as well as its relation to spermatozoa quality was investigated. The semen samples were analyzed by atomic absorption spectrophotometry (AAS). The concentration of copper in boar semen was 1.64 +/- 0.28 mg kg(-1) and of iron 16.14 +/- 10.35 mg kg(-1). The concentration of zinc in boar semen reached an average value of 171.74 +/- 64.72 mg kg(-1) and the level of cadmium reached 0.01-0.16 mg kg(-1) with the average value of 0.05 mg kg(-1). The analysis of lead showed that the concentration of this element in boar semen was 0.02 +/- 0.03 mg kg(-1) and the average level of nickel was 0.06 +/- 0.08 mg kg(-1). The total percentage of pathological spermatozoa was 9.82 +/- 1.47%. Detail analysis determined 3.18% of separated flagellum, 2.26% knob twisted flagellum, 0.88% flagellum torso, 0.85% flagellum ball, 0.42% broken flagellum, 0.23% retention of the cytoplasmic drop, 0.14% small heads, 0.03% large heads, and 1.83% forms other of pathological changes. Correlation analysis showed significant (p < 0.05) positive correlation between copper and lead (r = 0.52). High correlation between small head and knob twisted tail (r = 0.67), small head and broken flagellum (r = 0.88) as well as between small head and total number of pathological spermatozoa (r = 0.73) was determined. PMID:14533929

Massányi, Peter; Trandzík, Jozef; Nad, Pavol; Koréneková, Beáta; Skalická, Magdaléna; Toman, Robert; Lukác, Norbert; Strapák, Peter; Halo, Marko; Turcan, Ján

2003-01-01

131

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 ...

132

Iron  

MedlinePLUS

Iron is a mineral that our bodies need for many functions. For example, iron is part of hemoglobin, a protein which carries ... It helps our muscles store and use oxygen. Iron is also part of many other proteins and ...

133

Copper and iron isotope fractionation during weathering and pedogenesis: Insights from saprolite profiles  

NASA Astrophysics Data System (ADS)

Iron and copper isotopes are useful tools to track redox transformation and biogeochemical cycling in natural environment. To study the relationships of stable Fe and Cu isotopic variations with redox regime and biological processes during weathering and pedogenesis, we carried out Fe and Cu isotope analyses for two sets of basalt weathering profiles (South Carolina, USA and Hainan Island, China), which formed under different climatic conditions (subtropical vs. tropical). Unaltered parent rocks from both profiles have uniform ?56Fe and ?65Cu values close to the average of global basalts. In the South Carolina profile, ?56Fe values of saprolites vary from -0.01‰ to 0.92‰ in the lower (reduced) part and positively correlate with Fe3+/?Fe (R2 = 0.90), whereas ?65Cu values are almost constant. By contrast, ?56Fe values are less variable and negatively correlate with Fe3+/?Fe (R2 = 0.88) in the upper (oxidized) part, where large (4.85‰) ?65Cu variation is observed with most samples enriched in heavy isotopes. In the Hainan profile formed by extreme weathering under oxidized condition, ?56Fe values vary little (0.05-0.14‰), whereas ?65Cu values successively decrease from 0.32‰ to -0.12‰ with depth below 3 m and increase from -0.17‰ to 0.02‰ with depth above 3 m. Throughout the whole profile, ?65Cu positively correlate with Cu concentration and negatively correlate with the content of total organic carbon (TOC). Overall, the contrasting Fe isotopic patterns under different redox conditions suggest redox states play the key controls on Fe mobility and isotope fractionation. The negative correlation between ?56Fe and Fe3+/?Fe in the oxidized part of the South Carolina profile may reflect addition of isotopically light Fe. This is demonstrated by leaching experiments, which show that Fe mineral pools extracted by 0.5 N HCl, representing poorly-crystalline Fe (hydr)-oxides, are enriched in light Fe isotopes. The systematic Cu isotopic variation in the Hainan profile reflects desorption and downward transport of isotopically heavy Cu, leaving the organically-bound Cu enriched in light isotope as supported by the negative correlation of ?65Cu with TOC (R2 = 0.88). The contrasting (mostly positive vs. negative) Cu isotopic signatures in the upper parts of these two profiles can be attributed to the different climatic conditions, e.g., high rainfall at a tropical climate in Hainan favors desorption and the development of organism, whereas relatively dry climate in South Carolina favors Cu re-precipitation from soil solutions and adsorption onto Fe (hydr)-oxides. Our results highlight the potential applications of Fe and Cu isotopes as great tracers of redox condition, ancient climate and biological cycling during chemical weathering and pedogenic translocation.

Liu, Sheng-Ao; Teng, Fang-Zhen; Li, Shuguang; Wei, Gang-Jian; Ma, Jing-Long; Li, Dandan

2014-12-01

134

Concentrations of strontium, barium, cadmium, copper, zinc, manganese, chromium, antimony, selenium and lead in the liver and kidneys of dogs, depending on age, sex and the occurrence of a chronic kidney disease.  

PubMed

Only few data are available for the storage of elements in the organs of dogs. This study aimed at determining the concentrations of strontium (Sr), barium (Ba), cadmium (Cd), copper (Cu), zinc (Zn), manganese (Mn), chromium (Cr), antimony (Sb), selenium (Se) and lead (Pb) in the canine liver, renal cortex and renal medulla, evaluating also the relevance of age, sex and the occurrence of a chronic kidney disease (CKD). Therefore, tissues of 50 dogs were analyzed using inductively coupled plasma mass spectrometry. Cu, Zn and Mn were highest in the liver, followed by the renal cortex and the renal medulla. Highest Sr, Cd and Se concentrations were measured in the renal cortex, while markedly lower concentrations were found in the renal medulla and the liver. Female dogs showed higher tissue concentrations of Sr (liver; renal medulla), Cd (liver), Zn (liver; renal cortex), Cr (liver; renal cortex; renal medulla) and Pb (liver) than male dogs. Except for Mn and Sb, age-dependent variations were observed for all element concentrations in the canine tissues. The hepatic Cd and Cr concentrations were higher in dogs with CKD. In conclusion, the present results provide new knowledge on the storage of specific elements in the canine liver and kidneys and can be considered as important reference data for diagnostics and further investigations. PMID:25234328

Paßlack, Nadine; Mainzer, Barbara; Lahrssen-Wiederholt, Monika; Schafft, Helmut; Palavinskas, Richard; Breithaupt, Angele; Zentek, JÜrgen

2014-09-17

135

Iron superoxide dismutase from Escherichia coli at 3.1-A resolution: a structure unlike that of copper/zinc protein at both monomer and dimer levels.  

PubMed Central

The structure of iron superoxide dismutase (EC 1.15.1.1) from Escherichia coli has been determined at 3.1-A resolution. The dimeric molecule is constructed from identical subunits, which are two-domain polypeptides. The NH2-terminal domain is composed of two antiparallel crossing helices and the COOH-terminal domain is a three-layered structure characterized by mixed alpha/beta secondary structural features. The active center iron atoms, separated by 18 A and located near the monomer-monomer interface, are coordinated by two amino acid residues from each domain. Azide binding has been investigated by using difference Fourier techniques. Consistent with the notion of the independent evolution of the copper/zinc dismutase gene, the iron dismutase structure resembles the copper/zinc protein at neither the monomer nor the dimer level. PMID:6346322

Stallings, W C; Powers, T B; Pattridge, K A; Fee, J A; Ludwig, M L

1983-01-01

136

Effect of chronic cadmium administration on liver and kidney concentrations of zinc, copper, iron, manganese, and chromium  

SciTech Connect

Chronic Cd exposure in animals brings about significant morphological and functional changes in both liver and kidney. Most studies of cadmium effects on essential metal tissue distribution involve large concentrations of either Cd or essential metals added to the diet. The effect of Cd ingestion on trace metal metabolism of animals consuming usual diets may be marked, as elements whose physical and chemical properties are enough alike...will act antagonistically to each other biologically. Therefore, the purpose of the present study was to observe the effects of a chronic low dose of Cd added to an otherwise normal diet on the liver and kidney accumulation of zinc, copper, iron, manganese and chromium in the mouse at different times after the cessation of cadmium ingestion.

Friel, J.K.; Borgman, R.F.; Chandra, R.K.

1987-04-01

137

Neutron Scattering Studies of Cuprates and Iron Pnictides.  

E-print Network

??Presented within are neutron scattering studies of several different high temperature superconducting materials: BaFe1.9Ni0.1As2 [Barium Iron Nickel Arsenic], BaFe1.85Ni0.15As2 [Barium Iron Nickel Arsenic], Ba0.67K0.33Fe2As2 [Barium… (more)

Liu, Mengshu

2014-01-01

138

Iron, zinc and copper in the Alzheimer’s disease brain: a quantitative meta-analysis. Some insight on the influence of citation bias on scientific opinion  

PubMed Central

Dysfunctional homeostasis of transition metals is believed to play a role in the pathogenesis of Alzheimer’s disease (AD). Although questioned by some, brain copper, zinc, and particularly iron overload are widely accepted features of AD which have led to the hypothesis that oxidative stress generated from aberrant homeostasis of these transition metals might be a pathogenic mechanism behind AD. This meta-analysis compiled and critically assessed available quantitative data on brain iron, zinc and copper levels in AD patients compared to aged controls. The results were very heterogeneous. A series of heavily cited articles from one laboratory reported a large increase in iron in AD neocortex compared to age-matched controls (p<0.0001) while seven laboratories failed to reproduce these findings reporting no significant difference between the groups (p=0.76). A more than three-fold citation bias was found to favor outlier studies reporting increases in iron and this bias was particularly prominent among narrative review articles. Additionally, while zinc was not significantly changed in the neocortex (p=0.29), copper was significantly depleted in AD (p=0.0003). In light of these findings, it will be important to re-evaluate the hypothesis that transition metal overload accounts for oxidative injury noted in AD. PMID:21600264

Schrag, Matthew; Mueller, Claudius; Oyoyo, Udochukwu; Kirsch, Wolff M.

2011-01-01

139

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

140

Iron  

MedlinePLUS

... mealtime or when you take iron supplements.RiboflavinTaking riboflavin supplements may improve the way iron supplements work ... significant only in people with low levels of riboflavin.SoySoy protein seems to reduce the body's ability ...

141

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

142

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. PMID:22962679

Waters, Brian M.; Stein, Ricardo J.

2012-01-01

143

IRON  

EPA Science Inventory

The document surveys the effects of organic and inorganic iron that are relevant to humans and their environment. The biology and chemistry of iron are complex and only partially understood. Iron participates in oxidation reduction processes that not only affect its geochemical m...

144

Barium release system  

NASA Technical Reports Server (NTRS)

A chemical system is described for releasing a good yield of free barium neutral atoms and barium ions in the upper atmosphere and interplanetary space for the study of the geophysical properties of the medium. The barium is released in the vapor phase so that it can be ionized by solar radiation and also be excited to emit resonance radiation in the visible range. The ionized luminous cloud of barium becomes a visible indication of magnetic and electrical characteristics in space and allows determination of these properties over relatively large areas at a given time.

Lewis, B. W.; Stokes, C. S.; Smith, E. W.; Murphy, W. J. (inventors)

1973-01-01

145

Flow-injection determination of copper(II) based on its catalysis on the redox reaction of cysteine with iron(III) in the presence of 1,10-phenanthroline  

Microsoft Academic Search

A redox reaction of cysteine with iron(III) proceeds slowly in the presence of 1,10-phenanthroline (phen). However, this reaction is accelerated in the presence of copper(II) as a catalyst, producing an iron(II)–phen complex (?max=510 nm). A sensitive spectrophotometric flow-injection method is proposed for the determination of copper(II) based on its catalytic action on this redox reaction. The dynamic range was 0.1–10

Norio Teshima; Hideyuki Katsumata; Makoto Kurihara; Tadao Sakai; Takuji Kawashima

1999-01-01

146

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

147

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

Microsoft Academic Search

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

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

2010-01-01

148

Barium ferrite nanoparticles prepared directly by aerosol pyrolysis  

Microsoft Academic Search

BaFe12O19 nanoparticles, 10 nm in diameter, have been obtained by combination of two methods, the citrate precursor and the aerosol pyrolysis technique. For the first time, well-crystallised barium ferrite particles were obtained by pyrolysis of an aerosol, produced by ultrasonic frequency spraying of a barium iron citrate aqueous solution, in a tubular furnace at 1000°C, without further heat treatment. The

T González-Carreño; M. P Morales; C. J Serna

2000-01-01

149

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

150

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

Microsoft Academic Search

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.

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

1986-01-01

151

Biosorption of copper(II), lead(II), iron(III) and cobalt(II) on Bacillus sphaericus-loaded Diaion SP850 resin  

Microsoft Academic Search

The biosorption of copper(II), lead(II), iron(III) and cobalt(II) on Bacillus sphaericus-loaded Diaion SP-850 resin for preconcentration–separation of them have been investigated. The sorbed analytes on biosorbent were eluted by using 1molL?1 HCl and analytes were determined by flame atomic absorption spectrometry. The influences of analytical parameters including amounts of pH, B. sphaericus, sample volume etc. on the quantitative recoveries of

Mustafa Tuzen; Ozgur Dogan Uluozlu; Canan Usta; Mustafa Soylak

2007-01-01

152

Analysis of the fuel wood used in Late Bronze Age and Early Iron Age copper mining sites of the Schwaz and Brixlegg area (Tyrol, Austria)  

E-print Network

Charcoal analysis was carried out as part of an interdisciplinary project focusing on the copper mining history of the former mining area of Schwaz and Brixlegg, a region pivotal as a copper source in prehistoric Europe. The goal was to use remains of carbonised wood to investigate environmental implications of prehistoric mining, as well as to gain new insight about the ancient mining technique of fire-setting. Charcoal samples from seven copper mining sites (Late Bronze Age to Early Iron Age) were analysed. The results reveal a strong preference for coniferous wood as fuel in fire-setting, but not in ore smelting/roasting processes. Species composition at the ore-processing sites indicates moderate forest degradation processes caused by human intervention.

Andreas G. Heiss; Klaus Oeggl

2008-01-01

153

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 PMID:6264990

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

1981-01-01

154

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

155

Coumarin-Based Fluorescent Probes for Dual Recognition of Copper(II) and Iron(III) Ions and Their Application in Bio-Imaging  

PubMed Central

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?5 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

156

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

157

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

158

High Levels of Copper, Zinc, Iron and Magnesium, but not Calcium, in the Cerebrospinal Fluid of Patients with Fahr's Disease.  

PubMed

Patients with marked calcification of the basal ganglia and cerebellum have traditionally been referred to as having Fahr's disease, but the nomenclature has been criticized for including heterogeneous etiology. We describe 3 patients with idiopathic bilateral striatopallidodentate calcinosis (IBSPDC). The patients were a 24-year-old man with mental deterioration, a 57-year-old man with parkinsonism and dementia, and a 76-year-old woman with dementia and mild parkinsonism. The former 2 patients showed severe calcification of the basal ganglia and cerebellum, and the latter patient showed severe calcification of the cerebellum. We found significantly increased levels of copper (Cu), zinc (Zn), iron (Fe) and magnesium (Mg), using inductively coupled plasma mass spectrometry in the CSF of all these 3 patients. The increased levels of Cu, Zn, Fe and Mg reflect the involvement of metabolism of several metals and/or metal-binding proteins during the progression of IBSPDC. More numerous patients with IBSPDC should be examined in other races to clarify the common mechanism of the disease and to investigate the specific treatment. PMID:20671856

Hozumi, Isao; Kohmura, Akihiro; Kimura, Akio; Hasegawa, Tatsuya; Honda, Akiko; Hayashi, Yuichi; Hashimoto, Kazunori; Yamada, Megumi; Sakurai, Takeo; Tanaka, Yuji; Satoh, Masahiko; Inuzuka, Takashi

2010-01-01

159

High Levels of Copper, Zinc, Iron and Magnesium, but not Calcium, in the Cerebrospinal Fluid of Patients with Fahr's Disease  

PubMed Central

Patients with marked calcification of the basal ganglia and cerebellum have traditionally been referred to as having Fahr's disease, but the nomenclature has been criticized for including heterogeneous etiology. We describe 3 patients with idiopathic bilateral striatopallidodentate calcinosis (IBSPDC). The patients were a 24-year-old man with mental deterioration, a 57-year-old man with parkinsonism and dementia, and a 76-year-old woman with dementia and mild parkinsonism. The former 2 patients showed severe calcification of the basal ganglia and cerebellum, and the latter patient showed severe calcification of the cerebellum. We found significantly increased levels of copper (Cu), zinc (Zn), iron (Fe) and magnesium (Mg), using inductively coupled plasma mass spectrometry in the CSF of all these 3 patients. The increased levels of Cu, Zn, Fe and Mg reflect the involvement of metabolism of several metals and/or metal-binding proteins during the progression of IBSPDC. More numerous patients with IBSPDC should be examined in other races to clarify the common mechanism of the disease and to investigate the specific treatment. PMID:20671856

Hozumi, Isao; Kohmura, Akihiro; Kimura, Akio; Hasegawa, Tatsuya; Honda, Akiko; Hayashi, Yuichi; Hashimoto, Kazunori; Yamada, Megumi; Sakurai, Takeo; Tanaka, Yuji; Satoh, Masahiko; Inuzuka, Takashi

2010-01-01

160

Effect of dietary phytic acid and cadmium on the availability of cadmium, zinc, copper, iron, and manganese to rats  

SciTech Connect

The main route of cadmium intake for general population, both human and animal, is via ingestion. The intestinal absorption of cadmium is relatively low, 6% of a single oral dose for humans and less than 2% for various animal species. However, due to poor excretion, accumulation of cadmium occurs, primarily in kidney. The chronic exposure even to low levels of dietary cadmium can lead to the development of renal disturbances. Fox (1988) suggests that phytic acid might be a dietary component capable to influence the intestinal absorption of cadmium. Phytic acid naturally occurs as the major phosphorus storage constituent of most cereals, legumes, and oilseeds. At physiological pH, phytic acid is ionized and has a strong affinity for divalent cations. The potential of phytic acid to decrease the availability of Zn has been for long time of concern for nutritionists. Phytic acid has also been reported to decrease the availability of other trace metals. For nonessential elements, reduced availability of lead has been observed. The experimental data concerning the effect of dietary phytic acid on the availability of dietary cadmium are limited to the work of Rose and Quarterman (1984). The objective of this experiment was to examine: (1) the effect of dietary phytic acid on the availability of cadmium under conditions of chronic dietary exposure of rats to cadmium, and (2) the effect of dietary phytic acid and of chronic dietary exposure to cadmium on the availability of zinc, copper, iron, and manganese to rats. 19 refs., 4 tabs.

Turecki, T.; Ewan, R.C.; Stahr, H.M. [Iowa State Univ., Ames, IA (United States)

1995-05-01

161

Transcriptomic and physiological characterization of the fefe mutant of melon (Cucumis melo) reveals new aspects of iron-copper crosstalk.  

PubMed

Iron (Fe) and copper (Cu) homeostasis are tightly linked across biology. In previous work, Fe deficiency interacted with Cu-regulated genes and stimulated Cu accumulation. The C940-fe (fefe) Fe-uptake mutant of melon (Cucumis melo) was characterized, and the fefe mutant was used to test whether Cu deficiency could stimulate Fe uptake. Wild-type and fefe mutant transcriptomes were determined by RNA-seq under Fe and Cu deficiency. FeFe-regulated genes included core Fe uptake, metal homeostasis, and transcription factor genes. Numerous genes were regulated by both Fe and Cu. The fefe mutant was rescued by high Fe or by Cu deficiency, which stimulated ferric-chelate reductase activity, FRO2 expression, and Fe accumulation. Accumulation of Fe in Cu-deficient plants was independent of the normal Fe-uptake system. One of the four FRO genes in the melon and cucumber (Cucumis sativus) genomes was Fe-regulated, and one was Cu-regulated. Simultaneous Fe and Cu deficiency synergistically up-regulated Fe-uptake gene expression. Overlap in Fe and Cu deficiency transcriptomes highlights the importance of Fe-Cu crosstalk in metal homeostasis. The fefe gene is not orthologous to FIT, and thus identification of this gene will provide clues to help understand regulation of Fe uptake in plants. PMID:24975482

Waters, Brian M; McInturf, Samuel A; Amundsen, Keenan

2014-09-01

162

Copper stable isotopes as tracers of metal-sulphide segregation and fractional crystallisation processes on iron meteorite parent bodies  

NASA Astrophysics Data System (ADS)

We report high precision Cu isotope data coupled with Cu concentration measurements for metal, troilite and silicate fractions separated from magmatic and non-magmatic iron meteorites, analysed for Fe isotopes (? 57Fe; permil deviation in 57Fe/ 54Fe relative to the pure iron standard IRMM-014) in an earlier study ( Williams et al., 2006). The Cu isotope compositions (? 65Cu; permil deviation in 65Cu/ 63Cu relative to the pure copper standard NIST 976) of both metals (? 65Cu M) and sulphides (? 65Cu FeS) span much wider ranges (-9.30 to 0.99‰ and -8.90 to 0.63‰, respectively) than reported previously. Metal-troilite fractionation factors (? 65Cu M-FeS = ? 65Cu M - ? 65Cu FeS) are variable, ranging from -0.07 to 5.28‰, and cannot be explained by equilibrium stable isotope fractionation coupled with either mixing or reservoir effects, i.e. differences in the relative proportions of metal and sulphide in the meteorites. Strong negative correlations exist between troilite Cu and Fe (? 57Fe FeS) isotope compositions and between metal-troilite Cu and Fe (? 57Fe M-FeS) isotope fractionation factors, for both magmatic and non-magmatic irons, which suggests that similar processes control isotopic variations in both systems. Clear linear arrays between ? 65Cu FeS and ? 57Fe FeS and calculated Cu metal-sulphide partition coefficients (D Cu = [Cu] metal/[Cu] FeS) are also present. A strong negative correlation exists between ? 57Fe M-FeS and D Cu; a more diffuse positive array is defined by ? 65Cu M-FeS and D Cu. The value of D Cu can be used to approximate the degree of Cu concentration equilibrium as experimental studies constrain the range of D Cu between Fe metal and FeS at equilibrium to be in the range of 0.05-0.2; D Cu values for the magmatic and non-magmatic irons studied here range from 0.34 to 1.11 and from 0.04 to 0.87, respectively. The irons with low D Cu values (closer to Cu concentration equilibrium) display the largest ? 57Fe M-FeS and the lowest ? 65Cu M-FeS values, whereas the converse is observed in the irons with large values D Cu that deviate most from Cu concentration equilibrium. The magnitudes of Cu and Fe isotope fractionation between metal and FeS in the most equilibrated samples are similar: 0.25 and 0.32‰/amu, respectively. As proposed in an earlier study ( Williams et al., 2006) the range in ? 57Fe M-FeS values can be explained by incomplete Fe isotope equilibrium between metal and sulphide during cooling, where the most rapidly-cooled samples are furthest from isotopic equilibrium and display the smallest ? 57Fe M-FeS and largest D Cu values. The range in ? 65Cu M-FeS, however, reflects the combined effects of partial isotopic equilibrium overprinting an initial kinetic signature produced by the diffusion of Cu from metal into exsolving sulphides and the faster diffusion of the lighter isotope. In this scenario, newly-exsolved sulphides initially have low Cu contents (i.e. high D Cu) and extremely light ? 65Cu FeS values; with progressive equilibrium and fractional crystallisation the Cu contents of the sulphides increase as their isotopic composition becomes less extreme and closer to the metal value. The correlation between ? 65Cu M-FeS and ? 57Fe M-FeS is therefore a product of the superimposed effects of kinetic fractionation of Cu and incomplete equilibrium between metal and sulphide for both isotope systems during cooling. The correlations between ? 65Cu M-FeS and ? 57Fe M-FeS are defined by both magmatic and non-magmatic irons record fractional crystallisation and cooling of metallic melts on their respective parent bodies as sulphur and chalcophile elements become excluded from crystallised solid iron and concentrated in the residual melt. Fractional crystallisation processes at shallow levels have been implicated in the two main classes of models for the origin of the non-magmatic iron meteorites; at (i) shallow levels in impact melt models and (ii) at much deeper levels in models where the non-magmatic irons represent metallic melts that crystallised within the in

Williams, Helen M.; Archer, Corey

2011-06-01

163

Effect of Copper and Nickel on the Transformation Kinetics of Austempered Ductile Iron  

NASA Astrophysics Data System (ADS)

The kinetics of reaction occurring during the austempering treatment of ductile iron (DI) containing different additions of Cu and Ni was investigated in this work. DI bars were heat treated in an instrumented dilatometer in order to follow the exhibited transformation kinetics. The dilatometric results indicated that the addition of Cu alone did not have a significant effect on the incubation times for the austempering transformation. Also, the addition of both, Cu and Ni resulted in a significant effect on reducing the transformation rates. It was found that the austempering process is characterized by two clearly distinguished transformation stages. In the initial stage, the addition of Cu, and to a greater extent, additions of both Cu and Ni led to reductions in the transformation rates shifting the maximum transformation rate values toward longer times. The outcome of this work indicates that during the first stage of austempering, nucleation of the ferrite plates occurs via a diffusionless mechanism while their growth is diffusion controlled. Moreover, after the maximum in the transformation rate has been reached, the growth of ferrite plates becomes dominant with the rate-limiting step becoming the diffusion of C into the surrounding austenite. A qualitative model for the austempering transformation is proposed in this work to account for the experimental observations.

Górny, Marcin; Tyra?a, Edward; Lopez, Hugo

2014-10-01

164

Combined effects of ethanol and protein deficiency on hepatic iron, zinc, manganese, and copper contents.  

PubMed

The present study has been performed in order to establish the relative and combined roles of ethanol and malnutrition on liver Fe, Zn, Cu, and Mn alterations in alcoholic male adult Wistar rats, and also the relationships between these alterations and histomorphometrically determined hepatocyte and nuclear areas, perivenular fibrotic rim area, and total amount of fat present in the liver. Four groups of 8 animals each were fed: (1) a nutritionally adequate diet (C); (2) a 36% ethanol-containing (as percent of energy), isocaloric diet (A); (3) a 2% protein-containing, isocaloric diet (PD); and (4) a 36% ethanol, 2% protein-containing, isocaloric diet (A-PD), respectively, following the Lieber-DeCarli model. Ethanol-fed, protein-deficient animals showed the highest liver Fe, and the lowest Zn and Cu values, although differences in liver Zn, Mn, and Cu values were not significantly different between PD and A-PD groups. Statistically significant differences of these parameters were observed between the A and the A-PD groups, and between the A and PD groups, except for liver iron. Except for liver Mn, differences between C and A groups were statistically significant. These alterations correlated with liver fibrosis and steatosis, serum albumin, and weight loss, except for liver Mn, which was not correlated with fibrosis or steatosis. Thus, protein deficiency seems to enhance ethanol-induced liver Fe, Zn, and Cu alterations, whereas protein deficiency, but not ethanol, seems to play a major role on liver Mn alterations. PMID:1418656

Conde-Martel, A; González-Reimers, E; Santolaria-Fernández, F; Castro-Alemán, V; Galindo-Martín, L; Rodríguez-Moreno, F; Martínez-Riera, A

1992-01-01

165

Acute and subacute response of iron, zinc, copper and selenium in pigs experimentally infected with Actinobacillus pleuropneumoniae.  

PubMed

This study was performed to characterise the response of iron (Fe), zinc (Zn), copper (Cu) and selenium (Se) in bacterial-induced porcine acute phase reaction (APR). Twenty piglets were challenged by aerosolic infection with Actinobacillus pleuropneumoniae (A.pp.) serotype 2, ten piglets serving as controls. Blood sampling was done initially and at day 4 and 21 after infection, collection of liver tissue was done at day 21 (autopsy). A.pp.-infection caused fever and respiratory symptoms. APR at day 4 after infection was marked by an increase in total white blood cells, granulocytes and monocytes in whole blood samples and an increase in globulin/albumin ratio (G/A), ?2-globulins, C-reactive protein, haptoglobin, ceruloplasmin (Cp), Cu and Se in serum. Concurrently, there was a decrease in haemoglobin (Hb) and packed cell volume (PCV) in whole blood as well as a decrease in albumin, transferrin, total iron binding capacity and Fe in serum and Zn in plasma. The subacute stage at day 21 was characterised by progressively increased concentrations of G/A, ?-globulins and ?-globulins reflecting the specific immune reaction. Hb and PCV showed further decreases, all other parameters returned to the initial concentrations. Glutathione peroxidase activity in plasma and liver tissue remained unaffected by A.pp.-infection. The liver concentration (day 21) of Zn was found to be higher, that of Se was lower in the A.pp.-group, whereas hepatic concentrations of Cu and Fe were not affected by A.pp.-infection. In summary, the acute and subacute stages of A.pp.-infection were accurately characterised by the APR-related parameters. Se was only marginally affected by the A.pp.-infection. The elevated plasma Cu concentration may be a side effect of the transient hepatic induction of Cp synthesis. Zn responded, being distinctly reduced in plasma and probably having been sequestered in the liver tissue. Reduction in serum Fe can be regarded as an unspecific defence mechanism in A.pp.-infection to withdraw Fe from bacterial acquisition systems. PMID:25100437

Humann-Ziehank, Esther; Menzel, Anne; Roehrig, Petra; Schwert, Barbara; Ganter, Martin; Hennig-Pauka, Isabel

2014-10-01

166

Dynamic Aeolian Deposition of Glacial Iron to the Open Ocean: 2 Years of Time-Series Observations from Middleton Island and the Copper River Delta  

NASA Astrophysics Data System (ADS)

ron (Fe) is thought to be a limiting nutrient for phytoplankton in much of the north Pacific and the Gulf of Alaska (GoA) in particular. In the subarctic GoA, we have a limited knowledge of the role of glaciers in driving the supply of iron to marine ecosystem, and in particular, the role that dust derived from glacial flour plays in delivering bioavailable iron to the offshore ecosystems. In order to better understand glacial dust deposition in the GoA and its potential role in marine productivity, we combine time-series satellite, meteorological, and aerosol geochemical data from over 2 years of monitoring at Middleton Island and the Copper River Valley. Middleton Island is located on the edge of the continental shelf and is ideally positioned to monitor the flux of aerosol iron into adjacent Fe-limited waters, while the Copper River Delta and Valley are thought to be the source of much of the glacial dust that reaches Middleton. In fact, widespread dust events have been frequently observed (MODIS imagery) emanating from exposed floodplains within the heavily glacierized Copper River Valley. These events are most common in the fall, when high pressure in the AK interior and low pressure in the central GoA establish a pressure gradient that drives anomalously strong northerly winds capable of entraining the abundant glacial flour that is exposed under low water conditions in the Copper River floodplain. Here we present Fe geochemical data from continuous automated aerosol sampling on Middleton Island from 2011-2013. These time-series geochemical data, when coupled with MODIS and meteorological observations, present a remarkable opportunity to examine the drivers of these dust events and how inter-annual meteorological variability between dust seasons influences the annual flux of soluble Fe associated with these phenomena. The dust season of 2011-12, characterized by early and heavy snows and onshore winds, generated very little dust with minimal and infrequent iron deposition observed on Middleton Island and estimated via MODIS. This was in stark contrast to the dust season of 2012-2013, when sustained high offshore winds and dry conditions during the fall generated close to continuous strong dust activity for over a month and delivered a high flux of soluble glacial Fe offshore. As a whole, these time-series data reveal the dramatic inter-annual variability of the influence of glaciers on eolian iron deposition in offshore GoA waters, and clearly demonstrate that the potential role of glacial dust in marine nutrient cycles is highly dynamic and sensitive to regional and local climatological and hydrologic conditions.

Schroth, A. W.; Crusius, J.; Campbell, R. W.; Gasso, S.; Moy, C. M.

2013-12-01

167

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

168

Copper and Iron Homeostasis in Plants: The Challenges of Oxidative Stress  

PubMed Central

Abstract Significance: Photosynthesis, the process that drives life on earth, relies on transition metal (e.g., Fe and Cu) containing proteins that participate in electron transfer in the chloroplast. However, the light reactions also generate high levels of reactive oxygen species (ROS), which makes metal use in plants a challenge. Recent Advances: Sophisticated regulatory networks govern Fe and Cu homeostasis in response to metal ion availability according to cellular needs and priorities. Molecular remodeling in response to Fe or Cu limitation leads to its economy to benefit photosynthesis. Fe toxicity is prevented by ferritin, a chloroplastic Fe-storage protein in plants. Recent studies on ferritin function and regulation revealed the interplay between iron homeostasis and the redox balance in the chloroplast. Critical Issues: Although the connections between metal excess and ROS in the chloroplast are established at the molecular level, the mechanistic details and physiological significance remain to be defined. The causality/effect relationship between transition metals, redox signals, and responses is difficult to establish. Future Directions: Integrated approaches have led to a comprehensive understanding of Cu homeostasis in plants. However, the biological functions of several major families of Cu proteins remain unclear. The cellular priorities for Fe use under deficiency remain largely to be determined. A number of transcription factors that function to regulate Cu and Fe homeostasis under deficiency have been characterized, but we have not identified regulators that mediate responses to excess. Importantly, details of metal sensing mechanisms and cross talk to ROS-sensing mechanisms are so far poorly documented in plants. Antioxid. Redox Signal. 19, 919–932. PMID:23199018

Pilon, Marinus

2013-01-01

169

Barium Abundances in Cepheids  

E-print Network

We derived the barium atmospheric abundances for a large sample of Cepheids, comprising 270 stars. The sample covers a large range of galactocentric distances, from about 4 to 15 kpc, so that it is appropriated to investigate the existence of radial barium abundance gradients in the galactic disc. In fact, this is the first time that such a comprehensive analysis of the distribution of barium abundances in the galactic disc is carried out. As a result, we conclude that the Ba abundance distribution can be characterized by a zero gradient. This result is compared with derived gradients for other elements, and some reasons are briefly discussed for the independence of the barium abundances upon galactocentric distances.

Andrievsky, S M; Korotin, S A; Luck, R E; Kovtyukh, V V; Maciel, W J

2012-01-01

170

Fractionation of fulvic acid by iron and aluminum oxides--influence on copper toxicity to Ceriodaphnia dubia.  

PubMed

This study examines the effect on aquatic copper toxicity of the chemical fractionation of fulvic acid (FA) that results from its association with iron and aluminum oxyhydroxide precipitates. Fractionated and unfractionated FAs obtained from streamwater and suspended sediment were utilized in acute Cu toxicity tests on Ceriodaphnia dubia. Toxicity test results with equal FA concentrations (6 mg FA/L) show that the fractionated dissolved FA was 3 times less effective at reducing Cu toxicity (EC50 13 ± 0.6 ?g Cu/L) than were the unfractionated dissolved FAs (EC50 39 ± 0.4 and 41 ± 1.2 ?g Cu/L). The fractionation is a consequence of preferential sorption of molecules having strong metal-binding (more aromatic) moieties to precipitating Fe- and Al-rich oxyhydroxides, causing the remaining dissolved FA to be depleted in these functional groups. As a result, there is more bioavailable dissolved Cu in the water and hence greater potential for Cu toxicity to aquatic organisms. In predicting Cu toxicity, biotic ligand models (BLMs) take into account dissolved organic carbon (DOC) concentration; however, unless DOC characteristics are accounted for, model predictions can underestimate acute Cu toxicity for water containing fractionated dissolved FA. This may have implications for water-quality criteria in systems containing Fe- and Al-rich sediment, and in mined and mineralized areas in particular. Optical measurements, such as specific ultraviolet absorbance at 254 nm (SUVA254), show promise for use as spectral indicators of DOC chemical fractionation and inferred increased Cu toxicity. PMID:25289694

Smith, Kathleen S; Ranville, James F; Lesher, Emily K; Diedrich, Daniel J; McKnight, Diane M; Sofield, Ruth M

2014-10-21

171

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

PubMed

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. PMID:22442359

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

2012-03-01

172

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. PMID:24705926

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

2014-01-01

173

Copper and Copper Proteins in Parkinson's Disease  

PubMed Central

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

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

2014-01-01

174

Copper and copper proteins in Parkinson's disease.  

PubMed

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

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

2014-01-01

175

Analysis of 26 Barium Stars I. Abundances  

E-print Network

We present a detailed analysis of 26 barium stars, including dwarf barium stars, providing their atmospheric parameters (Teff, log g, [Fe/H], vt) and elemental abundances. We aim at deriving gravities and luminosity classes of the sample stars, in particular to confirm the existence of dwarf barium stars. Accurate abundances of chemical elements were derived. Abundance ratios between nucleosynthetic processes, by using Eu and Ba as representatives of the r- and s-processes are presented. High-resolution spectra with the FEROS spectrograph at the ESO-1.5m Telescope, and photometric data with Fotrap at the Zeiss telescope at the LNA were obtained. The atmospheric parameters were derived in an iterative way, with temperatures obtained from colour-temperature calibrations. The abundances were derived using spectrum synthesis for Li, Na, Al, alpha-, iron peak, s- and r-elements atomic lines, and C and N molecular lines. Atmospheric parameters in the range 4300 barium stars, were derived and showed that [X/Ba] vs. [Ba/H] and [X/Ba] vs. [Fe/H] present different behaviour as compared to [X/Eu] vs. [Eu/H] and [X/Eu] vs. [Fe/H], reflecting the different nucleosynthetic sites for the s- and r-processes.

Dinah M. Allen; Beatriz Barbuy

2006-04-03

176

London penetration depth measurements in Barium(Iron1-xTx)2Arsenic2 (T=Cobalt, Nickel,Ruthenium, Rhodium, Palladium, Platinum, Cobalt+Copper) superconductors  

NASA Astrophysics Data System (ADS)

The London penetration depth has been measured in various doping levels of single crystals of Ba(Fe1-xTx )2As2 (T=Co,Ni,Ru,Rh,Pd,Pt,Co+Cu) superconductors by utilizing a tunnel diode resonator (TDR) apparatus. All in-plane penetration depth measurements exhibit a power law temperature dependence, indicating the existence of low-temperature, normal state quasiparticles all the way down to the lowest measured temperature, which was typically 500 mK. Several different doping concentrations from the Ba(Fe1- xTx)2As2 (T=Co,Ni) systems have been measured and the doping dependence of the power law exponent, n, is compared to results from measurements of thermal conductivity and specific heat. In addition, a novel method has been developed to allow for the measurement of the zero temperature value of the in-plane penetration depth by using TDR frequency shifts. By using this technique, the doping dependence of the zero temperature value of the penetration depth has been measured in the Ba(Fe 1-xTx)2As 2 series, which has allowed also for the construction of the doping-dependent superfluid phase stiffness. By studying the effects of disorder on these superconductors using heavy ion irradiation, it has been determined that the observed power law temperature dependence likely arises from pair-breaking impurity scattering contributions, which is consistent with the proposed s+/- symmetry of the superconducting gap in the dirty scattering limit. This hypothesis is supported by the measurement of an exponential temperature dependence of the penetration depth in the intrinsically clean LiFeAs, indicative of a nodeless superconducting gap.

Gordon, Ryan T.

2011-12-01

177

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

178

The correlation between high background radiation and blood level of the trace elements (copper, zinc, iron and magnesium) in workers of Mahallat's hot springs  

PubMed Central

Background: Blood trace elements of people who are living or working in areas with high radioactivity have an important role in vital processes. The scope of this work is to measure the concentrations of blood trace elements of permanent workers in Mahallat's hot springs. Materials and Methods: In this study, 30 persons of hot springs permanent workers in Mahallat (mean background dose: 21.6 mSv) were selected as a sample group and 30 persons with similar social class who received a normal background dose and were not engaged in any type of radiation work were selected as a control group. Five milliliters of blood sample was taken from each person and after preparation of the samples, the concentration of copper, iron, zinc and magnesium was measured with atomic absorption spectrometry. Results: The average concentration of copper, iron, zinc and magnesium in the irradiated group was 0.67±0.11, 1.54±0.41, 1.76±0.34 and 19.78±1.42, respectively and in the control group, was 0.78±0.06, 1.06±0.15, 0.85±0.05 and 20.34±0.57, respectively. Values of copper and magnesium in workers were found to be less than that of the control group. The mean concentration of iron and zinc in permanent workers was significantly more than that of the control group (P<0.05). Overall, no meaningful statistical correlation was found between the concentration of magnesium among the permanent presence in the area (P>0.05). Conclusions: The results showed that increases in the average concentrations of Zn and Fe and decreases in the concentration of Cu of workers was observed. The finding also showed that the probability of chronic exposure effects on body trace element concentrations was increases and each value of the doses could be dangerous. PMID:23326795

Shahbazi-Gahrouei, Daryoush; Abdolahi, Mohammad

2012-01-01

179

Iron(III)- and copper(II) complexes of an asymmetric, pentadentate salen-like ligand bearing a pendant carboxylate group  

Microsoft Academic Search

The equilibrium and solution structural properties of the iron(III) and copper(II) complexes of an asymmetric salen-like ligand (N,N?-bis(2-hydroxybenzyl)-2,3-diamino-propionic acid, H3bhbdpa) bearing a pendant carboxylate group were characterized in aqueous solution by potentiometric, pH-dependent electron paramagnetic resonance (EPR) and UV–Vis (UV–Visible) measurements. In the equimolar systems the pentadentate ligand forms very stable, differently protonated mononuclear complexes with both metal ions. In

Attila Jancsó; Zoltán Paksi; Satu Mikkola; Antal Rockenbauer; Tamás Gajda

2005-01-01

180

Chelatometric determination of calcium and magnesium in iron ores, slags, anorthosite, limestone, copper-nickel-lead-zinc ores and divers materials.  

PubMed

Chelatometric methods for the determination of calcium and magnesium in iron ores, slags, anorthosite, copper-nickel-lead-zinc ores and various other materials are described. Potential interfering elements are masked with triethanolamine and potassium cyanide. In one aliquot calcium is titrated at pH > 12, with calcein and thymolphthalein mixed indicator and in another aliquot calcium and magnesium are titrated in ammonia buffer, with o-cresolphthalein complexone screened with Naphthol Green B as indicator. The results compare favourably with certified values for reference materials of diverse nature. PMID:18962661

Hitchen, A; Zechanowitsch, G

1980-03-01

181

Barium and Yttrium abundance in intermediate-age and old open clusters  

E-print Network

Barium is a neutron capture element, that, in open clusters, is frequently over-abundant with respect to the Iron. A clear explanation for this is still missing. Additionally, its gradient across the Galactic disk is poorly constrained. We measure the abundance of yttrium and barium using the synthetic spectrum method from UVES high-resolution spectra of eight distant open clusters, namely Ruprecht 4, Ruprecht 7, Berkeley 25, Berkeley 73, Berkeley 75, NGC 6192, NGC 6404, and NGC 6583. The barium abundance was estimated using NLTE approximation. We confirm that Barium is indeed over-abundant in most clusters, especially young clusters. Finally, we investigated the trend of yttrium and barium abundances as a function of distance in the Galaxy and ages. Several scenarios for the barium over-abundance are then discussed.

Mishenina, T; Carraro, G; Kovtyukh, V V; Yegorova, I A

2013-01-01

182

A Spectroscopic Analysis of Barium Stars  

NASA Astrophysics Data System (ADS)

Detailed abundance analyses have been carried out for 31 barium and normal G-K giant stars using high-dispersion spectra and model atmospheres. A significant enhancement of s-process elements is found for seventeen stars. The abundances of light and iron-peak elements are in general equal to those in the standard star ? Vir. However, Na, Mg, Mn, and Co are systematically slightly deficient (about 0.2 dex). The elements heavier than Ni are enhanced by up to about 1.5 dex compared with the standards, while the r-process element Eu abundance is roughly normal. We cannot find substantial differences in abundances, atmospheric parameters, and luminosities of radial- velocity variable and nonvariable barium stars. Therefore it seems that both groups of stars belong to a single family of peculiar giants. Comparison between the mean observed s-process abundances for our uniform barium star sample, and theoretical predictions from various neutron exposure models, show that 13C neutron source AGB star (with the mean neutron exposure ?0 > 0.4mb-1 can best reproduce the abundance data of these stars. Low neutron density single neutron exposures of approx. 1.1mb-1 also are shown to result in good agreement with the barium star observations. Mass transfer scenarios are tested using the chemical composition and orbital parameter data of Ba II stars. Since a correlation exists between s-process abundance anomalies and orbital periods (projections of the semi-major axis, mass functions) for barium star binaries, we conclude that a wind accretion scenario is more promising than Roche-lobe overflow ones. Abundance patterns for barium and carbon stars have been compared. We find good agreement for the iron group metals, but carbon stars show higher s-process element overabundances (0.9 dex in the mean). Therefore, the companions to the Ba II stars were perhaps once carbon stars, who overflowed mass onto the presently visible star with a second dilution (the ratio of the transferred mass to the mass of the receiving envelope) of roughly 0.9.

Zacs, L.

1994-03-01

183

Barium Ion Trapping Rebecca Schutzengel  

E-print Network

Barium Ion Trapping Rebecca Schutzengel Franklin W. Olin College of Engineering University of Washington INT REU August 20, 2012 Rebecca Schutzengel Barium Ion Trapping August 20, 2012 1 / 12 #12;Uses for Ion Trapping Bell's Inequality tests Quantum Computing Rebecca Schutzengel Barium Ion Trapping August

Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group

184

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

185

Identical flow injection spectrophotometric manifold for determination of protein, phosphorus, calcium, chloride, copper, manganese, iron, and zinc in feeds or premixes.  

PubMed

A simple procedure using an identical manifold was developed for determination of nitrogen (protein) phosphorus, calcium, chloride, copper, manganese, iron, and zinc in feeds and feedstuffs. By changing appropriate reagents and detection wavelength, these 8 elements were determined successively with a simple identical double-line flow injection (FI) manifold. Fl spectrophotometric determinations were made by the blue indophenol reaction for ammonium, the molybdenum blue method for phosphate, the cresolphthalein complexone procedure for calcium, and the mercuric thiocyanate procedure for chloride. The chromogenic reagents for copper, iron, manganese, and zinc determination were bis(cyclohexanone)oxalydihydrazone (Cuprizone), 1,10-phenanthroline, formaldoxime, and xylenol orange, respectively. Sample digestion catalyst, Fl manifold, and some chemical parameters were optimized. The proposed procedure had a sampling rate of 90/h for each analyte. The determination ranges (mg/L) were 10-60 for N, 1-15 for P and Ca, 540 for Cl, and 0.5-15 for Cu, Fe, Mn, and Zn, respectively. Results of the analyses of animal feed and feedstuff samples by this procedure did not differ significantly from those obtained by proven manual methods. PMID:11501921

Liu, J F; Feng, Y D; Jiang, G B

2001-01-01

186

Relative and combined effects of ethanol and protein deficiency on zinc, iron, copper, and manganese contents in different organs and urinary and fecal excretion.  

PubMed

The relative contribution of protein deficiency to the altered metabolism of certain trace elements in chronic alcoholics is not well defined, so this study was performed to analyse the relative and combined effects of ethanol and protein deficiency on liver, bone, muscle, and blood cell content of copper, zinc, iron, and manganese, and also on serum levels and urinary and fecal excretion of these elements in four groups of eight animals each that were pair-fed during 8 weeks with a nutritionally adequate diet, a 36% (as energy) ethanol-containing isocaloric diet, a 2% protein isocaloric diet, and a 36% ethanol 2% protein isocaloric diet, respectively, following the Lieber-DeCarli model. Five additional rats were fed ad lib the control diet. Protein malnutrition, but not ethanol, leads to liver zinc depletion. Both ethanol and protein malnutrition cause muscle zinc depletion and increase urinary zinc and manganese excretion, whereas ethanol also increases urinary iron excretion and liver manganese content. No differences were observed regarding copper metabolism. PMID:9650630

Gonzalez-Reimers, E; Martinez-Riera, A; Santolaria-Fernandez, F; Mas-Pascual, A; Rodriguez-Moreno, F; Galindo-Martin, L; Molina-Perez, M; Barros-Lopez, N

1998-07-01

187

Effects of microbial iron reduction and oxidation on the immobilization and mobilization of copper in synthesized Fe(III) minerals and Fe-rich soils.  

PubMed

The effects of microbial iron reduction and oxidation on the immobilization and mobilization of copper were investigated in a high concentration of sulfate with synthesized Fe(III) minerals and red earth soils rich in amorphous Fe (hydr)oxides. Batch microcosm experiments showed that red earth soil inoculated with subsurface sediments had a faster Fe(III) bioreduction rate than pure amorphous Fe(III) minerals and resulted in quicker immobilization of Cu in the aqueous fraction. Coinciding with the decrease of aqueous Cu, SO4(2-) in the inoculated red earth soil decreased acutely after incubation. The shift in the microbial community composite in the inoculated soil was analyzed through denaturing gradient gel electrophoresis. Results revealed the potential cooperative effect of microbial Fe(III) reduction and sulfate reduction on copper immobilization. After exposure to air for 144 h, more than 50% of the immobilized Cu was remobilized from the anaerobic matrices; aqueous sulfate increased significantly. Sequential extraction analysis demonstrated that the organic matter/sulfide-bound Cu increased by 52% after anaerobic incubation relative to the abiotic treatment but decreased by 32% after oxidation, indicating the generation and oxidation of Cu-sulfide coprecipitates in the inoculated red earth soil. These findings suggest that the immobilization of copper could be enhanced by mediating microbial Fe(III) reduction with sulfate reduction under anaerobic conditions. The findings have an important implication for bioremediation in Cucontaminated and Fe-rich soils, especially in acid-mine-drainage-affected sites. PMID:24448165

Hu, Chaohua; Zhang, Youchi; Zhang, Lei; Luo, Wensui

2014-04-01

188

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

189

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

190

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

191

Esophagram (Barium Swallow Study)  

MedlinePLUS

... up. You will be given a gown to wear. The esophagram barium swallow uses x-rays and anyone who is pregnant cannot be in the room during the x-ray. During the Test Before the study you/your child will need ...

192

Degradation of some typical pharmaceuticals and personal care products with copper-plating iron doped Cu2O under visible light irradiation.  

PubMed

A mixture of five commonly used pharmaceuticals and personal care products (PPCPs) was degraded using a new combined catalyst under visible light irradiation. Scanning electron microscopy and X-ray diffraction analysis revealed that the combined catalyst was composed of copper-plating iron doped Cu2O (FeCu/Cu2O). Compared with the Fe/C inner micro-circuit, the electric currents flowing between Cu and Fe increase the speed of anodic Fe dissolution. Moreover, due to the photochemical properties, Cu2O can accelerate the PPCPs degradation processes under the irradiation of visible light. In addition, shaking increased the dissolved oxygen concentration in the solution, which not only preconditioned the photo-catalysis reaction, but also set the stage for Fe reduction. According to the experimental results, we propose the possible reaction mechanism of the reaction. PMID:22893958

An, Jing; Zhou, Qixing

2012-01-01

193

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

194

The influence of the production technology of iron-copper composite alloy on its erosion properties in a high-current high-pressure arc  

NASA Astrophysics Data System (ADS)

The electrical erosion properties of material based on a pseudo-alloy of copper and iron CuFe (85/15%) obtained by layered cladding are compared with the erosion of CuW (25/75%) and CuFe (70/30%) obtained by conventional powder alloying. Erosion of electrodes has been measured for arcs in the range of current amplitudes from 50 to 150 kA at an air pressure from 20 Pa to 2 MPa. Specific erosion has been determined as a function of current and gas pressure. The specific erosion of the new material is ˜1 mg/C at the level of materials produced by conventional powder technology.

Budin, A. V.; Pinchuk, M. E.; Kuznetsov, V. E.; Rutberg, F. G.

2014-12-01

195

75 FR 33824 - Barium Chloride From China  

Federal Register 2010, 2011, 2012, 2013, 2014

...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

196

75 FR 19657 - Barium Chloride From China  

Federal Register 2010, 2011, 2012, 2013, 2014

...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

197

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

198

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

199

Evaluating In-Situ Reactions of Chlorine and Chloramines at the Surface of Copper and Iron using Microelectrodes  

EPA Science Inventory

Corrosion of drinking water plumbing materials is a significant cause of deterioration of treated drinking water quality and a failure to supply safe water to the public. As a result of the Lead and Copper Rule, many water utilities in the US have developed and evaluated corrosio...

200

SOURCES OF COPPER AIR EMISSIONS  

EPA Science Inventory

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

201

Calcium, potassium, iron, copper and zinc concentrations in the white and gray matter of the cerebellum and corpus callosum in brain of four genetic mouse strains  

NASA Astrophysics Data System (ADS)

In the central nervous system, metallic cations are involved in oligodendrocyte maturation and myelinogenesis. Moreover, the metallic cations have been associated with pathogenesis, particularly multiple sclerosis and malignant gliomas. The brain is vulnerable to either a deficit or an excess of available trace elements. Relationship between trace metals and myelinogenesis is important in understanding a severe human pathology : the multiple sclerosis, which remains without efficient treatment. One approach to understand this disease has used mutant or transgenic mice presenting myelin deficiency or excess. But to date, the concentration of trace metals and mineral elements in white and gray matter areas in wild type brain is unknown. The aim of this study is to establish the reference concentrations of trace metals (iron, copper and zinc) and minerals (potassium and calcium) in the white and gray matter of the mouse cerebellum and corpus callosum. The brains of four different genetic mouse strains (C57Black6/SJL, C57Black6/D2, SJL and C3H) were analyzed. The freeze-dried samples were prepared to allow PIXE (Proton-induced X-ray emission) and RBS (Rutherford backscattering spectrometry) analyses with the nuclear microprobe in Bordeaux. The results obtained give the first reference values. Furthermore, one species out of the fours testes exhibited differences in calcium, iron and zinc concentrations in the white matter.

Sergeant, C.; Vesvres, M. H.; Devès, G.; Guillou, F.

2005-04-01

202

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

Microsoft Academic Search

The resonance Raman spectrum of the blue copper protein azurin from Alcaligenes denitrificans exhibits nine vibrational modes between 330 and 460 cm⁻¹, seven of which shift 0.4-3.0 cm⁻¹ to lower energy after incubation of the protein in DâO. These deuterium-dependent shifts have been previously ascribed to exchangeable protons on imidazole ligands or to exchangeable protons on amide groups which are

Yoshiki Mino; Thomas M. Loehr; Keishiro Wada; Hiroshi Matsubara; Joann Sanders-Loehr

1987-01-01

203

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. PMID:24430662

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

2014-01-01

204

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

2014-05-01

205

Comparison of injectable iron complexes in their ability to iron load tissues and to induce oxidative stress  

Microsoft Academic Search

Iron and copper homeostasis have been studied in various tissues after iron-loading with the polynuclear ferric hydroxide carbohydrate complexes, iron dextran, iron polymaltose, iron sucrose and iron gluconate for four weeks. There were significant increases in the iron content of the different rat tissues compared to controls, with the exception of the brain, which showed no change in its iron

R. Legssyer; P. Geisser; Harry McArdle; R. R. Crichton; R. J. Ward

2003-01-01

206

Barium uranyl diphosphonates  

SciTech Connect

Three Ba{sup 2+}/UO{sub 2}{sup 2+} 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 Degree-Sign C. These compounds, Ba[UO{sub 2}[CH{sub 2}(PO{sub 3}){sub 2}]{center_dot}1.4H{sub 2}O (Ba-1), Ba{sub 3}[(UO{sub 2}){sub 4}(CH{sub 2}(PO{sub 3}){sub 2}){sub 2}F{sub 6}]{center_dot}6H{sub 2}O (Ba-2), and Ba{sub 2}[(UO{sub 2}){sub 2}(CH{sub 2}(PO{sub 3}){sub 2})F{sub 4}]{center_dot}5.75H{sub 2}O (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 UO{sub 5}F{sub 2} 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 [UO{sub 2}[CH{sub 2}(PO{sub 3}){sub 2}]{sup 2-} sheets. The interlayer space of the structures is occupied by Ba{sup 2+}, which, along with the fluoride ion, mediates the structure formed and maintains overall charge balance. - Graphical abstract: Illustration of the stacking of the layers in Ba{sub 3}[(UO{sub 2}){sub 4}(CH{sub 2}(PO{sub 3}){sub 2}){sub 2})F{sub 6}]{center_dot}6H{sub 2}O viewed along the c-axis. The structure is constructed from UO{sub 7} pentagonal bipyramidal units, U(1)O{sub 7}=gray, U(2)O{sub 7}=yellow, barium=blue, phosphorus=magenta, fluorine=green, oxygen=red, carbon=black, and hydrogen=light peach. Highlights: Black-Right-Pointing-Pointer The polymerization of the UO{sub 2}{sup 2+} sites to form uranyl dimers leads to structural variations in compounds. Black-Right-Pointing-Pointer Barium cations stitch uranyl diphosphonate anionic layers together, and help mediate structure formation. Black-Right-Pointing-Pointer HF acts as both a mineralizing agent and a ligand.

Nelson, Anna-Gay D., E-mail: nelsoa@umich.edu [Department of Civil Engineering and Geological Sciences and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States); Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109-1005 (United States); Alekseev, Evgeny V. [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Juelich Wilhelm-Johnen-Strasse, Juelich 52428 (Germany); Ewing, Rodney C. [Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109-1005 (United States); Albrecht-Schmitt, Thomas E. [Department of Civil Engineering and Geological Sciences and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States)

2012-08-15

207

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

208

Synthesis and Characterization of New Alkoxotitanates of Yttrium, Barium, and Copper: Single Crystal X-ray Diffraction Structures of Cl(2)Y{Ti(2)(OPr(i))(9)}, {Ti(OPr(i))(5)}Ba{Ti(2)(OPr(i))(9)}, and ClCu{Ti(2)(OPr(i))(9)}  

PubMed

The synthesis and characterization of new mixed-metal alkoxides of titanium with yttrium, barium, and copper, achieved via salt elimination and acid-base reactions, is described. The metathesis reactions of KTi(2)(OPr(i))(9) with anhydrous YCl(3) (1:1 and 2:1) and CuCl(2) (1:1) afford chloro-functionalized heterobimetallic alkoxides Cl(2)Y{Ti(2)(OPr(i))(9)} (1), ClY{Ti(2)(OPr(i))(9)}(2) (2), and ClCu{Ti(2)(OPr(i))(9)} (3), respectively, in high yields. The barium-titanium derivatives [Ba{Ti(2)(OPr(i))(10)}](2) (4), {Ti(2)(OPr(i))(9)}Ba{Ti(OPr(i))(5)} (5), and Ba{Ti(2)(OPr(i))(9)}(2) (6) result from the reaction between [Ba(OPr(i))(2)](n) and Ti(OPr(i))(4) in 1:2, 1:3, and 1:4 molar ratios, respectively. All the new derivatives (1-6) have been characterized by elemental analyses, variable-temperature (1)H and (13)C NMR, infrared spectroscopy, cryoscopy, and single crystal X-ray diffraction studies for 1, 3, and 5. The crystallographic study of 1 reveals a mononuclear species where the yttrium atom, coordinated by four alkoxide oxygen atoms of the {Ti(2)(OPr(i))(9)}(-) unit and two chloride ligands, is in a pseudo-octahedral arrangement. The NMR ((1)H and (13)C) and cryoscopic data for 1 indicate that the bioctahedral {Ti(2)(OPr(i))(9)} framework, as observed in the solid state structure, is retained in solution also. The X-ray structure of copper derivative 3 exhibits a triangular heterometallic core CuTi(2)(&mgr;(2)-OPr(i))(3)(&mgr;(3)-OPr(i))(2) with chloride as a terminal ligand on copper. Each titanium bears two terminal OPr(i) groups and displays a distorted octahedral geometry whereas copper has a pseudotrigonal bipyramidal environment. The high-temperature NMR studies for the paramagnetic 3 are in agreement with Curie law behavior; the isotropic shifts indicate that the OPr(i) groups bound directly to the Cu(II) center experience a greater paramagnetic influence in comparison to OPr(i) groups attached to titanium only. Barium titanates reveal an interesting observation of structural and stoichiometry (Ba/Ti) change. The dimeric compound 4 (Ba/Ti, 1:2) reacts with 1 mol of Ti(OPr(i))(4) to offer mononuclear 5 with a Ba/Ti stoichiometry of 1:3; on further addition of 1 mol of Ti(OPr(i))(4), 5 is converted to 6 (Ba/Ti, 1:4). X-ray crystallography performed on 5 shows the molecular structure to be formed by the coordination of monoanionic {Ti(OPr(i))(5)}(-) and {Ti(2)(OPr(i))(9)}(-) units to Ba(2+) in bi- and tetradentate fashion, respectively. The coordination figure of the central atom, barium, corresponds to a trigonal prism distorted toward an octahedron. Crystal data for 1: monoclinic space group Cc, a = 21.618(14) Å, b = 9.878(5) Å, c = 19.949(13) Å, beta = 109.51(4) degrees, V = 4015(4) Å(3), Z = 4. Crystal data for 3: triclinic space group P&onemacr;, a = 10.085(2) Å, b = 10.210(2) Å, c = 21.551(4) Å, alpha = 84.40(3) degrees, beta = 84.03(3) degrees, gamma = 60.86(3) degrees, V = 1924.9(6) Å(3), Z = 2. Crystal data for 5: triclinic space group P&onemacr;, a = 11.850(2)Å, b = 13.888(3) Å, c = 18.716(4) Å, alpha = 86.08(3) degrees, beta = 89.15(3) degrees, gamma = 83.36(3) degrees, V = 3052.3(11) Å(3), Z = 4. PMID:11669876

Veith, Michael; Mathur, Sanjay; Huch, Volker

1997-05-21

209

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

210

Electrothermal atomic absorption spectrometric determination of cadmium, copper, iron, lead, and selenium in fruit slurry: analytical application to nutritional and toxicological quality control.  

PubMed

A method is described for direct determination of cadmium, copper, iron, lead, and selenium in slurried fruit samples by electrothermal atomic absorption spectrometry. The fresh samples were suspended in Triton X-100 and shaken with 10 g zirconia spheres until a slurry was formed. The graphite furnace conditions were optimized for each element. The detection limits were 0.3, 3.5, 15.0, 0.5, and 10.0 ng/g for Cd, Cu, Fe, Pb, and Se, respectively. Accuracy and precision were checked against sample mineralization in a microwave acid-digestion bomb. Results for analyses of National Institute of Standards and Technology standard reference materials agreed closely with certified values. Analytical application of this method was tested with 40 samples of 8 widely consumed fruit species. The mean values (referred to fresh weight of edible fraction) for each fruit species had ranges of 0.0003-0.050 microgram/g for Cd, 0.316-1.094 micrograms/g for Cu, 2.00-5.50 micrograms/g for Fe, 0.050-0.396 microgram/g for Pb, and 0.010-0.020 microgram/g for Se. The proposed method is useful for routine multielemental analysis in nutritional and toxicological quality control of fruits and similar foodstuffs. PMID:7580318

Cabrera, C; Lorenzo, M L; Lopez, M C

1995-01-01

211

Biosorption of copper(II), lead(II), iron(III) and cobalt(II) on Bacillus sphaericus-loaded Diaion SP-850 resin.  

PubMed

The biosorption of copper(II), lead(II), iron(III) and cobalt(II) on Bacillus sphaericus-loaded Diaion SP-850 resin for preconcentration-separation of them have been investigated. The sorbed analytes on biosorbent were eluted by using 1 mol L(-1) HCl and analytes were determined by flame atomic absorption spectrometry. The influences of analytical parameters including amounts of pH, B. sphaericus, sample volume etc. on the quantitative recoveries of analytes were investigated. The effects of alkaline, earth alkaline ions and some metal ions on the retentions of the analytes on the biosorbent were also examined. Separation and preconcentration of Cu, Pb, Fe and Co ions from real samples was achieved quantitatively. The detection limits by 3 sigma for analyte ions were in the range of 0.20-0.75 microg L(-1) for aqueous samples and in the range of 2.5-9.4 ng g(-1) for solid samples. The validation of the procedure was performed by the analysis of the certified standard reference materials (NRCC-SLRS 4 Riverine Water, SRM 2711 Montana soil and GBW 07605 Tea). The presented method was applied to the determination of analyte ions in green tea, black tea, cultivated mushroom, boiled wheat, rice and soil samples with successfully results. PMID:17386450

Tuzen, Mustafa; Uluozlu, Ozgur Dogan; Usta, Canan; Soylak, Mustafa

2007-01-01

212

Field trials to assess the use of iron-bearing industrial by-products for stabilisation of chromated copper arsenate-contaminated soil.  

PubMed

Two industrial by-products with high iron contents were tested for their effectiveness in the stabilisation of arsenic and trace metals in chromated copper arsenate (CCA)-contaminated soil. Steel abrasive (SA; 97% Fe(0)) and oxygen scarfing granulate (OSG; 69% Fe(3)O(4)) were applied at levels of 1% and 8% (w/w) respectively to two soils with different organic matter contents. Field lysimeter measurements indicated that SA and OSG treatments decreased the arsenic concentration in pore water by 68% and 92%, respectively, for the soil with low organic matter content, and by about 30% in pore water of soil with high organic matter content. At pH < or =6, the amended soil with low organic content contained elevated levels of manganese and nickel in their pore water, which were sufficient to induce cytotoxic effects in L-929 mouse fibroblast cells. The industrial by-products have significant potential for soil amendment at field-scale, but caution is required because of the potential release of their chemical contaminants and their reduced capacity for sorption of arsenic in organic-rich soils. PMID:17804040

Lidelöw, Sofia; Ragnvaldsson, Daniel; Leffler, Per; Tesfalidet, Solomon; Maurice, Christian

2007-11-15

213

Discovery of the Barium Isotopes  

E-print Network

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

A. Shore; A. Fritsch; J. Q. Ginepro; M. Heim; A. Schuh; M. Thoennessen

2009-08-13

214

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

215

Barium light source method and apparatus  

NASA Technical Reports Server (NTRS)

Visible light emission is obtained from a plasma containing elemental barium including neutral barium atoms and barium ion species. Neutral barium provides a strong green light emission in the center of the visible spectrum with a highly efficient conversion of electrical energy into visible light. By the selective excitation of barium ionic species, emission of visible light at longer and shorter wavelengths can be obtained simultaneously with the green emission from neutral barium, effectively providing light that is visually perceived as white. A discharge vessel contains the elemental barium and a buffer gas fill therein, and a discharge inducer is utilized to induce a desired discharge temperature and barium vapor pressure therein to produce from the barium vapor a visible light emission. The discharge can be induced utilizing a glow discharge between electrodes in the discharge vessel as well as by inductively or capacitively coupling RF energy into the plasma within the discharge vessel.

Curry, John J. (Inventor); MacDonagh-Dumler, Jeffrey (Inventor); Anderson, Heidi M. (Inventor); Lawler, James E. (Inventor)

2002-01-01

216

The SLC31 (Ctr) copper transporter family  

Microsoft Academic Search

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

Michael J. Petris

2004-01-01

217

Clean hydrometallurgical route to recover zinc, silver, lead, copper, cadmium and iron from hazardous jarosite residues produced during zinc hydrometallurgy.  

PubMed

A hydrometallurgical process for treating the hazardous jarosite residue from zinc hydrometallurgy was proposed, for not only detoxifying the residue, but also recovering the contained valuable metal components. The jarosite was initially activated and decomposed by sintering at 650°C for 1h. The sintered residue was leached in 6mol L(-1) aqueous NH(4)Cl solution at 105°C, followed by filtration. The leaching extraction of Zn, Pb, Cu, Cd and Ag are more than 95%. During reduction with Zn powder, more than 93% of Pb, Cu, Ag and Cd can be simultaneously recovered. Then the NH(4)Cl leaching residue were leached again in 30wt% aqueous NaOH solution for 1h at 160°C, and about 94% of As and 73% of Si were removed from the residue. The final residue was almost completely detoxified, and contains about 55wt% Fe, which can be used as an iron concentration. PMID:21684683

Ju, Shaohua; Zhang, Yifei; Zhang, Yi; Xue, Peiyi; Wang, Yihui

2011-08-30

218

Abundance analysis of barium and mild barium stars  

E-print Network

High signal to noise, high resolution spectra were obtained for a sample of normal, mild barium, and barium giants. Atmospheric parameters were determined from the FeI and FeII lines. Abundances for Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, La, Ce, Nd, Sm, Eu, and Gd, were determined from equivalent widths and model atmospheres in a differential analysis, with the red giant Eps Vir as the standard star. The different levels of s-process overabundances of barium and mild barium stars were earlier suggested to be related to the stellar metallicity. Contrary to this suggestion, we found in this work no evidence of barium and mild barium to having different range in metallicity. However, comparing the ratio of abundances of heavy to light s-process elements, we found some evidence that they do not share the same neutron exposure parameter. The exact mechanism controlling this difference is still not clear. As a by-product of this analysis we identify two normal red giants misclassified as mild barium stars. The relevance of this finding is discussed. Concerning the suggested nucleosynthetic effects possibly related to the s-process, for elements like Cu, Mn, V and Sc, we found no evidence for an anomalous behavior in any of the s-process enriched stars analyzed here. However, further work is still needed since a clear [Cu/Fe] vs. [Ba/H] anticorrelation exists for other s-process enriched objects.

R. Smiljanic; G. F. Porto de Mello; L. da Silva

2007-04-02

219

Barium and CH Stars The classical barium (or ``Ba II'') stars are red  

E-print Network

Barium and CH Stars The classical barium (or ``Ba II'') stars are red giants whose spectra show strong absorption lines of barium, strontium, and certain other heavy elements, as well as strong transfer in binary sys­ tems that drastically alters the surface compo­ sition of a companion star. Barium

Bond, Howard E.

220

Role of intermediate milling in the processing of nano-size particles of barium hexaferrite via co-precipitation method  

Microsoft Academic Search

Nano-crystalline particles of barium hexaferrite (BaFe12O19) have been prepared by a co-precipitation\\/mechanical milling technique using aqueous solutions of iron and barium chlorides with a Fe\\/Ba molar ratio of 11 and subsequent mechanical milling with a high energy planetary mill. The thermal properties, phase composition and morphology of the products were studied. DTA\\/TGA results confirmed by those obtained from XRD indicated

K. Sheikhi Moghaddam; A. Ataie

2006-01-01

221

Effect of breeding season and pregnancy status on serum progesterone, sodium, potassium, copper and iron of estrous synchronized Aradi goat does  

PubMed Central

Eighteen out of 88 estrous synchronized Aradi goat does were randomly chosen to be bled during May–July (Out breeding season, n = 9) and during September–December (Within breeding season, n = 9). Estrous synchronization was applied by using a control internal drug release (CIDR) as a reproductive management regimen throughout the year. Nineteen days after CIDR insertion, a 500 IU eCG was injected (i.m.) and CIDR was removed. Does were subjected to fertile bucks 48-60 h after CIDR removal. Jugular blood samples were collected in non-heparinized Vacutainer tubes at 0 h just before CIDR insertion, every 3 days during CIDR insert, at day of CIDR removal, at incidence of estrus and mating, at day 1, 8 and 30 post mating. Data on pregnancy were recorded and serum levels of progesterone (P), sodium (Na), potassium (K), copper (Cu) and iron (Fe) were determined. Progesterone concentration was higher (p < 0.05) within (2.85 ± 0.15 ng/ml) than outside (2.37 ± 0.13 ng/ml) the breeding season. Pregnant does exhibited higher (p < 0.05) levels of progesterone (2.76 ± 0.17 ng/ml) than non-pregnant does (2.37 ± 0.10 ng/ml). No significant interaction was found between season and pregnancy status on progesterone concentration. A typical progesterone profile was found during treatment days, as levels of P increased during CIDR insertion and declined at CIDR removal and thereafter. Neither breeding season nor pregnancy status affected Na+ concentration. Contrariwise, mean levels of K+ was higher (p < 0.05) outside (148.34 ± 3.91 mg/L) than within (136.27 ± 3.91 mg/L) the breeding season. Pregnancy status did not influence K concentration. Sodium/potassium (Na+/K+) ratio was significantly (p < 0.01) higher within (30.29 ± 0.44) than outside (27.62 ± 0.44) the breeding season. On the contrary, pregnancy status did not affect this ratio. Iron concentrations neither affected by season nor pregnancy. Likewise, Cu concentrations were not affected by season, however Cu levels were higher (p < 0.05) in pregnant (147.75 ± 7.24 ?g/L) than in non-pregnant (127.31 ± 5.03 ?g/L) does. PMID:23961088

Al-Sobaiyl, K.A.

2010-01-01

222

Iron, copper, zinc and bromine mapping in cirrhotic liver slices from patients with hemochromatosis studied by microscopic synchrotron radiation X-ray fluorescence analysis in continuous scanning mode  

NASA Astrophysics Data System (ADS)

Iron (Fe) and copper (Cu) are essential metals in physiological cell metabolism. While Fe is easy to determine biochemically in histological slices, Cu and zinc (Zn) distribution is frequently critical in confirming the presence of an overload in disturbed Fe/Cu metabolism. To analyze Fe, Cu and Zn in a near histological resolution, energy dispersive microscopic synchrotron radiation X-ray fluorescence was applied. In normal liver tissue, after fixation and imbedding in paraffin, mean Fe, Cu and Zn concentrations were 152 ± 54, 20.1 ± 4.3 and 88.919.5 ?g/g sample weight, respectively. No substantial, characteristic differences in their distribution were found in the two-dimensional scans. In slices from patients with hemochromatosis mean Fe, Cu and Zn concentrations were 1102 ± 539, 35.9 ± 14.6 and 27.2 ± 6.7 ?g/g sample weight, respectively. Additionally, a significant decrease in phosphorus and sulphur concentrations existed. An increased Cu around cirrhotic regenerations nodules is mostly associated with a lymphocytic infiltration in this region. Analyzing concentrations of Fe in different regions of the samples show a clear negative dependency between Fe and Cu, Cu and Zn, but a positive one between Fe and Zn. Conclusion: With a focal beam size of 15 ?m in diameter a resolution of the elemental distribution was achieved which is widely comparable with stained histological slices (20× light microscope). The analysis of simultaneous determined elements reveals metabolic differences between Fe, Cu and Zn in liver tissue from patients with hemochromatosis.

Osterode, W.; Falkenberg, G.; Höftberger, R.; Wrba, F.

2007-07-01

223

Mesopelagic carbon remineralization during the European Iron Fertilization Experiment  

Microsoft Academic Search

The impact of iron fertilization on mesopelagic carbon (C) remineralization was assessed during the European Iron Fertilization Experiment (EIFEX) in the Southern Ocean by following the temporal change of excess particulate barium (also called biogenic or Baxs) in the mesopelagic waters of a mesoscale eddy. Before the iron infusion the site was already sustaining a significant vertical flux of particles

S. H. M. Jacquet; N. Savoye; F. Dehairs; V. H. Strass; D. Cardinal

2008-01-01

224

Barium Ions for Quantum Computation Matthew Dietrich  

E-print Network

Barium Ions for Quantum Computation Matthew Dietrich A dissertation submitted in partial of the manuscript made from microform." Signature Date #12;#12;University of Washington Abstract Barium Ions Department of Physics Barium ion is investigated as a hyperfine qubit. 137Ba+ is trapped in a linear Paul

Blinov, Boris

225

Quantum manipulation on the Barium quadrupolar transition  

E-print Network

Quantum manipulation on the Barium quadrupolar transition A diploma thesis in physics submitted and stabilization of a new fiber laser system to ma- nipulate the Barium quadrupolar transition, with the aim with a single Barium ion trapped in a linear Paul trap and Doppler cooled to the Lamb Dicke regime. The narrow

Blatt, Rainer

226

Iron and Iron Deficiency  

MedlinePLUS

... iron. (NIH) back to top Iron Overload and Hemochromatosis Iron overload is the accumulation of excess iron in body tissues. Hemochromatosis is the disease resulting from significant iron overload. ...

227

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

228

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

229

The Abundance Pattern of Two Barium Stars in the Galactic Halo: HD 104340 and HD 206983  

NASA Astrophysics Data System (ADS)

We present the abundance pattern of two barium stars in the Galactic halo, HD 104340 and HD 206983, based on high-resolution optical spectra. We also determined the spectroscopic stellar atmospheric parameters, temperature, and microturbulent velocity, as well as stellar surface gravity from a solution of excitation and ionization equilibria of Fe I and Fe II lines under the assumption of local thermodynamic equilibrium. The abundance analysis reveals HD 104340 to be a metal-poor K giant with [Fe/H]=-1.72 and HD 206983 also a metal-poor K giant with [Fe/H]=-1.43. From a set of Fe I lines, the radial velocity is found to be 263.3+/-0.6 km s-1 and -319.2+/-4.4 km s-1 for HD 104340 and HD 206983, respectively. Their high velocity, low metallicity, and high galactic latitude imply that both stars are members of a Galactic halo population. From our study and by using information from the literature we believe that HD 206983 is another member of a group known as metal-deficient barium stars. We compare the abundance pattern with the abundances of a halo population. We found that the abundances of the iron group, ?-elements, manganese, copper, and zinc, as well as sodium and magnesium, of HD 104340 and HD 206983 follow the abundance pattern of a halo population. The heavy element abundance pattern of both stars shows enhancement by a factor of 4-8 with respect to the metal-poor stars with the same metallicity as that analyzed by us. We also discuss the abundances of the s-process elements and compare our results with other objects that display the same degree of enrichment due to neutron capture reactions, binary systems, and AGB stars, through a diagram of metallicity versus neutron exposure given by the [hs/ls] index. Based on the observations made with the 1.52 m telescope at the European Southern Observatory (La Silla, Chile) under agreement with Observatório Nacional (Brazil).

Junqueira, S.; Pereira, C. B.

2001-07-01

230

40 CFR 721.10011 - Barium calcium manganese strontium oxide.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 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...

2011-07-01

231

40 CFR 721.10011 - Barium calcium manganese strontium oxide.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 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...

2010-07-01

232

40 CFR 721.10011 - Barium calcium manganese strontium oxide.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 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...

2012-07-01

233

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

234

40 CFR 721.10011 - Barium calcium manganese strontium oxide.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 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...

2014-07-01

235

Are There Any Stars Lacking Neutron-Capture Elements? Evidence from Strontium and Barium  

E-print Network

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]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, like magnesium, calcium, or iron, although the yields of heavy elements may be more variable.

Roederer, Ian U

2012-01-01

236

Microstructure and hysteresis curves of the barium hexaferrite from co-precipitation by organic agent  

NASA Astrophysics Data System (ADS)

This work correlates the magnetic hysteresis curves to the microstructure of the sintered polycrystalline barium hexaferrite discs produced from co-precipitated barium and iron citrates. Citric acid was used as the organic precipitating agent. Thermogravimetric and differential thermal analyses were performed on the co-precipitated product in order to guide its calcination into barium hexaferrite crystals, which was confirmed by means of the X-ray fluorescence and X-ray diffraction. After that, the hexaferrite powder was pressed in a steel die and submitted to firing in air at various temperatures. The final ceramic pieces were characterized by means of scanning electron microscopy and magnetic hysteresis grapher. The obtained results indicate a strong effect of the firing temperature on the microstructure, which in turn affected the magnetic hysteresis curve.

Ogasawara, T.; Oliveira, M. A. S.

2000-07-01

237

The Porphyromonas gingivalis HmuY haemophore binds gallium(iii), zinc(ii), cobalt(iii), manganese(iii), nickel(ii), and copper(ii) protoporphyrin IX but in a manner different to iron(iii) protoporphyrin IX.  

PubMed

Porphyromonas gingivalis, a major etiological agent of chronic periodontitis, acquires haem from host haemoproteins through a haem transporter HmuR and a haemophore HmuY. The aim of this study was to analyse the binding specificity of HmuY towards non-iron metalloporphyrins which may be employed as antimicrobials to treat periodontitis. HmuY binds gallium(iii), zinc(ii), cobalt(iii), manganese(iii), nickel(ii), and copper(ii) protoporphyrin IX but in a manner different to iron(iii) protoporphyrin IX which uses His(134) and His(166) as axial ligands. The metal ions in Ga(iii)PPIX and Zn(ii)PPIX can accept only His(166) as an axial ligand, whereas nickel(ii) and copper(ii) interact exclusively with His(134). Two forms of pentacoordinate manganese(iii) are present in the Mn(iii)PPIX-HmuY complex since the metal accepts either His(134) or His(166) as a single axial ligand. The cobalt ion is hexacoordinate in the Co(iii)PPIX-HmuY complex and binds His(134) and His(166) as axial ligands; however, some differences in their environments exist. Despite different coordination modes of the central metal ion, gallium(iii), zinc(ii), cobalt(iii), and manganese(iii) protoporphyrin IX bound to the HmuY haemophore cannot be displaced by excess haem. All of the metalloporphyrins examined bind to a P. gingivalis wild-type strain with higher ability compared to a mutant strain lacking a functional hmuY gene, thus corroborating binding of non-iron metalloporphyrins to purified HmuY protein. Our results further clarify the basis of metalloporphyrin acquisition by P. gingivalis and add to understanding of the interactions with porphyrin derivatives which exhibit antimicrobial activity against P. gingivalis. PMID:23392445

Wójtowicz, Halina; Bielecki, Marcin; Wojaczy?ski, Jacek; Olczak, Mariusz; Smalley, John W; Olczak, Teresa

2013-04-01

238

The problem of the barium stars  

NASA Technical Reports Server (NTRS)

Ultraviolet observations of barium stars and other cool stars with peculiar element abundances are reported. Those observations attempted to find hot white dwarf companions. Among six real barium stars studied, only Zeta Cap was found to have a white dwarf companion. Among seven mild, or marginal, barium stars studied, at least three were found to have hot subluminous companions. It is likely that all of them have white dwarf companions.

Bohm-Vitense, E.; Nemec, J.; Proffitt, C.

1984-01-01

239

Copper in microbial pathogenesis: meddling with the metal  

PubMed Central

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

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

2012-01-01

240

75 FR 20625 - Barium Chloride From China  

Federal Register 2010, 2011, 2012, 2013, 2014

...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

241

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

Microsoft Academic Search

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

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

2005-01-01

242

Hydrothermal alteration, fluid inclusions and stable isotope systematics of the Alvo 118 iron oxide-copper-gold deposit, Carajás Mineral Province (Brazil): Implications for ore genesis  

NASA Astrophysics Data System (ADS)

The Alvo 118 iron oxide-copper-gold (IOCG) deposit (170 Mt at 1.0 wt.% Cu, 0.3 g/t Au) lies in the southern sector of the Itacaúnas Shear Belt, Carajás Mineral Province, along a WNW-ESE-striking, 60-km-long shear zone, close to the contact of the ~2.76-Ga metavolcano-sedimentary Itacaiúnas Supergroup and the basement (~3.0 Ga Xingu Complex). The Alvo 118 deposit is hosted by mafic and felsic metavolcanic rocks and crosscutting granitoid and gabbro intrusions that have been subjected to the following hydrothermal alteration sequence towards the ore zones: (1) poorly developed sodic alteration (albite and scapolite); (2) potassic alteration (biotite or K-feldspar) accompanied by magnetite formation and silicification; (3) widespread, pervasive chlorite alteration spatially associated with quartz-carbonate-sulphide infill ore breccia and vein stockworks; and (4) local post-ore quartz-sericite alteration. The ore assemblage is dominated by chalcopyrite (~60%), bornite (~10%), hematite (~20%), magnetite (10%) and subordinate chalcocite, native gold, Au-Ag tellurides, galena, cassiterite, F-rich apatite, xenotime, monazite, britholite-(Y) and a gadolinite-group mineral. Fluid inclusion studies in quartz point to a fluid regime composed of two distinct fluid types that may have probably coexisted within the timeframe of the Cu-Au mineralizing episode: a hot (>200°C) saline (32.8‰ to 40.6 wt.% NaCl eq.) solution, represented by salt-bearing aqueous inclusions, and a lower temperature (<200°C), low to intermediate salinity (<15 wt.% NaCl eq.) aqueous fluid defined by two-phase (LH2O + VH2O) fluid inclusions. This trend is very similar to those defined for other IOCG systems of the Carajás Mineral Province. ? 18OH2O values in equilibrium with calcite (-1.0‰ to 7.5‰ at 277°C to 344°C) overlap the lower range for primary magmatic waters, but the more 18O-depleted values also point to the involvement of externally derived fluids, possibly of meteoric origin. Furthermore, sulphide ? 34S values (5.1‰ to 6.3‰), together with available boron isotope and Cl/Br-Na/Cl data provide evidence for a significant component of residual evaporative fluids (e.g., bittern fluids generated by seawater evaporation) in this scenario that, together with magma-derived brines, would be the main sources of the highly saline fluids involved in the formation Alvo 118 IOCG deposit. The restricted high temperature sodic alteration, the pervasive overprinting of the potassic alteration minerals by chlorite proximal to the ore zones, ore breccias with open-space filling textures in brittle structures, microthermometric and stable isotope data indicate, collectively, that the Alvo 118 IOCG system developed at structurally high levels and may be considered the shallower representative of the IOCG systems of the CMP.

Torresi, Ignacio; Xavier, Roberto Perez; Bortholoto, Diego F. A.; Monteiro, Lena V. S.

2012-03-01

243

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

244

Communications to the Editor Synthesis of Monodisperse Nanoparticles of Barium  

E-print Network

Communications to the Editor Synthesis of Monodisperse Nanoparticles of Barium Titanate: Toward of barium titanate, BaTiO3, with diameters ranging from 6 to 12 nm. Barium titanate is a room,10 In the synthesis developed here, barium titanium ethyl hexano-isopropoxide (A

245

Copper stabilizes the Menkes copper-transporting ATPase (Atp7a) protein expressed in rat intestinal epithelial cells  

PubMed Central

Iron deficiency decreases oxygen tension in the intestinal mucosa, leading to stabilization of hypoxia-inducible transcription factor 2? (Hif2?) and subsequent upregulation of genes involved in iron transport [e.g., divalent metal transporter (Dmt1) and ferroportin 1 (Fpn1)]. Iron deprivation also alters copper homeostasis, reflected by copper accumulation in the intestinal epithelium and induction of an intracellular copper-binding protein [metallothionein (Mt)] and a copper exporter [Menkes copper ATPase (Atp7a)]. Importantly, Atp7a is also a Hif2? target. It was, however, previously noted that Atp7a protein expression was induced more strongly than mRNA in the duodenum of iron-deprived rats, suggesting additional regulatory mechanisms. The current study was thus designed to decipher mechanistic aspects of Atp7a regulation during iron deprivation using an established in vitro model of the mammalian intestine, rat intestinal epithelial (IEC-6) cells. Cells were treated with an iron chelator and/or copper loaded to mimic the in vivo situation. IEC-6 cells exposed to copper showed a dose-dependent increase in Mt expression, confirming intracellular copper accumulation. Iron chelation with copper loading increased Atp7a mRNA and protein levels; however, contrary to our expectation, copper alone increased only protein levels. This suggested that copper increased Atp7a protein levels by a posttranscriptional regulatory mechanism. Therefore, to determine if Atp7a protein stability was affected, the translation inhibitor cycloheximide was utilized. Experiments in IEC-6 cells revealed that the half-life of the Atp7a protein was ?41 h and, furthermore, that intracellular copper accumulation increased steady-state Atp7a protein levels. This investigation thus reveals a novel mechanism of Atp7a regulation in which copper stabilizes the protein, possibly complementing Hif2?-mediated transcriptional induction during iron deficiency. PMID:23174565

Xie, Liwei

2013-01-01

246

Copper Sulfide Precipitation by Yeasts from Acid Mine-Waters  

PubMed Central

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

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

1967-01-01

247

Selective adsorption of lead, copper and antimony in runoff water from a small arms shooting range with a combination of charcoal and iron hydroxide.  

PubMed

Metals and metalloids from ammunition residues at small arms shooting ranges leach into the soil and surrounding watercourses and may pose a threat to exposed wildlife and humans. To reduce the potential impact of heavy metal on the environment a field study was performed with different sorbents in order to reduce the metal concentration in polluted water from a shooting range. Two sorbents were tested in situ for their ability to reduce the concentration of Cu, Sb and Pb: Brimac(®) charcoal and Kemira(®) iron hydroxide. The mean sorption of Cu, Sb and Pb was 85%, 65%, and 88% respectively when using the charcoal and 60%, 85% and 92% respectively with the iron hydroxide. Even better sorption of the elements was achieved when the two sorbents were combined in order to increase their selectivity. The best results were achieved in the filter in which the water percolated the charcoal first and the iron hydroxide last, with a mean sorption of Cu, Sb and Pb of 89%, 90% and 93% respectively. This preparation gave a significant better sorption of Cu compared to the filter in which the water percolated the iron hydroxide first and the charcoal last. The different effect between the two filters may be due to pH, since charcoal has alkaline properties and iron hydroxide has acidic properties. For large scale experiments or in filter devices we therefore recommend use of a combination of different reactive sorbents. PMID:25527987

Mariussen, Espen; Johnsen, Ida Vaa; Strømseng, Arnljot Einride

2015-03-01

248

Thin films preparation by rf-sputtering of copper\\/iron ceramic targets with Cu\\/Fe = 1: From nanocomposites to delafossite compounds  

Microsoft Academic Search

In the Cu–Fe–O phase diagram, delafossite CuFeO2 is obtained for the CuI oxidation state and for the Cu\\/Fe=1 ratio. By decreasing the oxygen content, copper\\/spinel oxide composite can be obtained because of the reduction and the disproponation of cuprous ions. Many physical properties as for instance, electrical, optical, catalytic properties can then be affected by the control of the oxygen

E. Mugnier; A. Barnabe; L. Presmanes; Ph. Tailhades

2008-01-01

249

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

250

Magnetic and dielectric properties of barium titanate-coated barium ferrite  

Microsoft Academic Search

Flaky barium ferrite with hexagonal molecular structure was successfully prepared by reverse microemulsion method, and was coated with barium titanate through a coordination–precipitation technique. The prepared composite particles were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), vibrating sample magnetometry (VSM) and vector network analyzer. Barium ferrite nanoparticles are proved to be single magnetic

Chao Wang; Xijiang Han; Ping Xu; Xiaohong Wang; Xueai Li; Hongtao Zhao

2009-01-01

251

Barium Sulfate Scale Formation in Oil Reservoir During Water Injection at High-Barium Formation Water  

NASA Astrophysics Data System (ADS)

This study presents the results of laboratory experiments carried out to investigate the formation of barium sulfate in sandstone cores from mixing injected sea water and formation water contain high concentration of barium at various temperatures (50 and 80°C) and differential pressures (100, 150 and 200 psig). The morphology of scaling crystals as shown by Scanning Electron Microscopy (SEM) is presented. Results show a large extent of permeability damage caused by barium sulfate deposits on the rock pore surface. The rock permeability decline indicates the influence of the concentration of barium ions.

Merdhah, Amer Badr Bin; Mohd Yassin, Abu Azam

252

Abundance Analysis of Barium Stars  

E-print Network

We obtain the chemical abundances of six barium stars and two CH subgiant stars based on the high signal-to-noise ratio and high resolution Echelle spectra. The neutron capture process elements Y, Zr, Ba, La, Eu show obvious overabundance relative to the Sun, for example, their [Ba/Fe] values are from 0.45 to 1.27. Other elements, including Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Ni, show comparable abundances to the Solar ones, and their [Fe/H] cover a range from $-$0.40 to 0.21, which means they belong to Galactic disk. The predicts of the theoretical model of wind accretion for binary systems can explain the observed abundance patterns of the neutron capture process elements in these stars, which means that their overabundant heavy-elements could be caused by accreting the ejecta of AGB stars, the progenitors of the present white dwarf companions in the binary systems.

G. Q. Liu; Y. C. Liang; L. Deng

2008-11-13

253

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

254

Impact of vanadium ions in barium borate glass  

NASA Astrophysics Data System (ADS)

Combined optical and infrared spectral measurements of prepared barium borate glasses containing different concentrations of V2O5 were carried out. Vanadium containing glasses exhibit extended UV-visible (UV/Vis.) bands when compared with base binary borate glass. UV/Vis. spectrum shows the presence of an unsymmetrical strong UV broad band centered at 214 nm attributed to the presence of unavoidable trace iron impurities within the raw materials used for the preparation of such glass. The calculated direct and indirect optical band gaps are found to decrease with increasing the vanadium content (2.9:137 for indirect and 3.99:2.01 for direct transition). This change was discussed in terms of structural changes in the glass network. Infrared absorption spectra of the glasses reveal the appearance of both triangular and tetrahedral borate units. Electron spin resonance analyses indicate the presence of unpaired species in sufficient quantity to be identified and to confirm the spectral data.

Abdelghany, A. M.; Hammad, Ahmed H.

2015-02-01

255

Dielectric and Piezoelectric Properties of Barium Titanate  

Microsoft Academic Search

The dielectric constant and loss of barium titanate and barium-strontium titanate have been measured at biasing field strengths from 0 to 5 megavolts per meter, at temperatures from -50°C to +135°C and at frequencies from 0.1 to 25 megacycles. The measurements versus temperature indicate the expected agreement with the Curie-Weiss law at temperatures above the Curie point. Measurements versus field

Shepard Roberts

1947-01-01

256

Fabrication of Barium Ferrite Thick Films  

Microsoft Academic Search

During recent years the need for high quality self-biased barium ferrite (BaFe12O19) thick films had been increasing due to its chemical stability, anisotropy and oriented hexagonal M-type ferrites. Our goal is to fabricate barium ferrite thick films to be incorporated in self-biased microwave devises. Different methods such as sputtering, pulse laser deposition, CVD and modified liquid phase deposition have been

Wei Jiang Yeh; Carla Blengeri-Oyarce; Sundeep Pillamari; Jnana Manoj Appikonda; Laura Diaz; Yanko Kranov; David McIlroy

2008-01-01

257

Barium hexaferrite synthesis by oxalate precursor route  

Microsoft Academic Search

Magnetic materials are important electronic materials that have a wide range of industrial and commercial applications. Barium hexaferrite (BaFe12O19), is of great importance as permanent magnets, particularly for magnetic recording as well as in microwave devices. An aim of this study was to synthesize stoichiometric and single phase barium hexaferrite by a technique of oxalate precursor. Effect of different annealing

Q. Mohsen

2010-01-01

258

Sulphate removal from sodium sulphate-rich brine and recovery of barium as a barium salt mixture.  

PubMed

Sulphate removal from sodium sulphate-rich brine using barium hydroxide and recovery of the barium salts has been investigated. The sodium sulphate-rich brine treated with different dosages of barium hydroxide to precipitate barium sulphate showed sulphate removal from 13.5 g/L to less than 400 mg/L over 60 min using a barium to sulphate molar ratio of 1.1. The thermal conversion of precipitated barium sulphate to barium sulphide achieved a conversion yield of 85% using coal as both a reducing agent and an energy source. The recovery of a pure mixture of barium salts from barium sulphide, which involved dissolution of barium sulphide and reaction with ammonium hydroxide resulted in recovery of a mixture of barium carbonate (62%) and barium hydroxide (38%), which is a critical input raw material for barium salts based acid mine drainage (AMD) desalination technologies. Under alkaline conditions of this barium salt mixture recovery process, ammonia gas is given off, while hydrogen sulfide is retained in solution as bisulfide species, and this provides basis for ammonium hydroxide separation and recovery for reuse, with hydrogen sulfide also recoverable for further industrial applications such as sulfur production by subsequent stripping. PMID:23485244

Vadapalli, Viswanath R K; Zvimba, John N; Mulopo, Jean; Motaung, Solly

2013-01-01

259

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

PubMed

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

Eskici, Gözde; Axelsen, Paul H

2012-08-14

260

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. PMID:24367764

Porcheron, Gaëlle; Garénaux, Amélie; Proulx, Julie; Sabri, Mourad; Dozois, Charles M.

2013-01-01

261

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

PubMed Central

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

Cooksey, Donald A.; Azad, Hamid R.

1992-01-01

262

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

Microsoft Academic Search

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.

Shigehiro Kagaya; Yasuko Araki; Noriyasu Hirai; Kiyoshi Hasegawa

2005-01-01

263

Copper hypersensitivity.  

PubMed

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

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

2014-10-01

264

Redesigning the blue copper azurin into a redox-active mononuclear nonheme iron protein: preparation and study of Fe(II)-M121E azurin.  

PubMed

Much progress has been made in designing heme and dinuclear nonheme iron enzymes. In contrast, engineering mononuclear nonheme iron enzymes is lagging, even though these enzymes belong to a large class that catalyzes quite diverse reactions. Herein we report spectroscopic and X-ray crystallographic studies of Fe(II)-M121E azurin (Az), by replacing the axial Met121 and Cu(II) in wild-type azurin (wtAz) with Glu and Fe(II), respectively. In contrast to the redox inactive Fe(II)-wtAz, the Fe(II)-M121EAz mutant can be readily oxidized by Na2IrCl6, and interestingly, the protein exhibits superoxide scavenging activity. Mössbauer and EPR spectroscopies, along with X-ray structural comparisons, revealed similarities and differences between Fe(II)-M121EAz, Fe(II)-wtAz, and superoxide reductase (SOR) and allowed design of the second generation mutant, Fe(II)-M121EM44KAz, that exhibits increased superoxide scavenging activity by 2 orders of magnitude. This finding demonstrates the importance of noncovalent secondary coordination sphere interactions in fine-tuning enzymatic activity. PMID:25082811

Liu, Jing; Meier, Katlyn K; Tian, Shiliang; Zhang, Jun-Long; Guo, Hongchao; Schulz, Charles E; Robinson, Howard; Nilges, Mark J; Münck, Eckard; Lu, Yi

2014-09-01

265

Temperature-dependent coherent oscillation in photorefractive relaxor strontium barium  

E-print Network

Temperature-dependent coherent oscillation in photorefractive relaxor strontium barium niobate M of the photorefractive light-induced scattering (beam fanning) in Sr0.61Ba0.39Nb2O6 (strontium barium niobate) doped

Osnabrück, Universität

266

Determination of calcium, copper, iron, magnesium, manganese, potassium, phosphorus, sodium, and zinc in fortified food products by microwave digestion and inductively coupled plasma-optical emission spectrometry: single-laboratory validation and ring trial.  

PubMed

A single-laboratory validation (SLV) and a ring trial (RT) were undertaken to determine nine nutritional elements in food products by inductively coupled plasma-optical emission spectrometry in order to modernize AOAC Official Method 984.27. The improvements involved extension of the scope to all food matrixes (including infant formula), optimized microwave digestion, selected analytical lines, internal standardization, and ion buffering. Simultaneous determination of nine elements (calcium, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, and zinc) was made in food products. Sample digestion was performed through wet digestion of food samples by microwave technology with either closed- or open-vessel systems. Validation was performed to characterize the method for selectivity, sensitivity, linearity, accuracy, precision, recovery, ruggedness, and uncertainty. The robustness and efficiency of this method was proven through a successful RT using experienced independent food industry laboratories. Performance characteristics are reported for 13 certified and in-house reference materials, populating the AOAC triangle food sectors, which fulfilled AOAC criteria and recommendations for accuracy (trueness, recovery, and z-scores) and precision (repeatability and reproducibility RSD, and HorRat values) regarding SLVs and RTs. This multielemental method is cost-efficient, time-saving, accurate, and fit-for-purpose according to ISO 17025 Norm and AOAC acceptability criteria, and is proposed as an extended updated version of AOAC Official Method 984.27 for fortified food products, including infant formula. PMID:22468357

Poitevin, Eric

2012-01-01

267

Two barium stars in the Galactic bulge  

E-print Network

Barium stars conserve important information on the s-process and the third dredge-up in intermediate mass stars. Their discovery in various environments is therefore of great help to test nucleosynthesis and mixing models. Our aim is to analyse two stars with a very strong barium line detected in a large survey of red giants in the Galactic bulge. Abundance analysis was done comparing synthetic model spectra based on the COMARCS code with our medium resolution spectra. Abundances of Ba, La, Y, and Fe were determined. Beside the two main targets, the analysis was also applied to two comparison stars. We confirm that both stars are barium stars. They are the first ones of this kind identified in the Galactic bulge. Their barium excesses are among the largest values found up to now. The elemental abundances are compared with current nucleosynthesis and mixing models. Furthermore, we estimate a frequency of barium stars in the Galactic bulge of about 1%, which is identical to the value for disc stars.

Lebzelter, Thomas; Straniero, Oscar; Aringer, Bernhard

2013-01-01

268

Two barium stars in the Galactic bulge  

NASA Astrophysics Data System (ADS)

Context. Barium stars conserve important information on the s-process and the third dredge-up in intermediate mass stars. Their discovery in various environments is therefore of great help in testing nucleosynthesis and mixing models. Aims: Our aim is to analyse two stars with a very strong barium line detected in a large survey of red giants in the Galactic bulge. Methods: Abundance analysis was done comparing synthetic model spectra based on the COMARCS code with our medium resolution spectra. Abundances of Ba, La, Y, and Fe were determined. Beside the two main targets, the analysis was also applied to two comparison stars. Results: We confirm that both stars are barium stars. They are the first ones of this kind identified in the Galactic bulge. Their barium excesses are among the largest values found up to now. The elemental abundances are compared with current nucleosynthesis and mixing models. Furthermore, we estimate a frequency of barium stars in the Galactic bulge of about 1%, which is identical to the value for disc stars. Based on observations at the Very Large Telescope of the European Southern Observatory, Cerro Paranal/Chile, under Programme 083.D-0046(A).

Lebzelter, T.; Uttenthaler, S.; Straniero, O.; Aringer, B.

2013-06-01

269

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

270

Copper Metallochaperones  

PubMed Central

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

Robinson, Nigel J.; Winge, Dennis R.

2014-01-01

271

Simultaneous removal of nitrate and heavy metals by iron metal*  

PubMed Central

Great attention should be paid now to simultaneously removing common pollutants, especially inorganic pollutants such as nitrate and heavy metals, as individual removal has been investigated extensively. Removing common pollutants simultaneously by iron metal is a very effective alternative method. Near neutral pH, heavy metals, such as copper and nickel, can be removed rapidly by iron metal, while nitrate removal very much slower than that of copper and nickel, and copper can accelerate nitrate removal when both are removed simultaneously. Even a little amount of copper can enhance nitrate removal efficiently. Different mechanisms of these contaminants removal by iron metal were also discussed. PMID:15822139

Hao, Zhi-wei; Xu, Xin-hua; Jin, Jian; He, Ping; Liu, Yong; Wang, Da-hui

2005-01-01

272

Ferroelectric Properties of Individual Barium Titanate Nanowires Investigated  

E-print Network

Ferroelectric Properties of Individual Barium Titanate Nanowires Investigated by Scanned Probe on the ferroelectric properties of individual single-crystalline barium titanate nanowires. We show that nonvolatile report the scanned probe characterization of individual single-crystalline barium titanate (BaTiO3) nano

Heller, Eric

273

Magnetoresistive Conductive Polyaniline-Barium Titanate Nanocomposites with Negative Permittivity  

E-print Network

Magnetoresistive Conductive Polyaniline-Barium Titanate Nanocomposites with Negative Permittivity Carolina 28301, United States ABSTRACT: Polyaniline (PANI) polymer nanocomposites (PNCs) filled with barium field sensors,10 energy electrodes11 and biosensors.12,13 Barium titanate (BaTiO3) as transition metal

Guo, John Zhanhu

274

PHOTOSENSITIVE CENTERS AND CHARGE TRANSFER PROCESSES IN BARIUM CALCIUM TITANATE  

E-print Network

PHOTOSENSITIVE CENTERS AND CHARGE TRANSFER PROCESSES IN BARIUM CALCIUM TITANATE G.MALOVICHKO, V@uos.de; vgrachev@uos.de; schirmer@uos.de Abstract The results of the study of charge transfer processes in barium of crystals from barium titanate (BT) family make them promising candidates for various applications

Malovichko, Galina

275

Experiments with remote entanglement using single barium ions Nathan Kurz  

E-print Network

Experiments with remote entanglement using single barium ions Nathan Kurz A dissertation submitted entanglement using single barium ions Nathan Kurz Chair of the Supervisory Committee: Dr. Boris B. Blinov Physics Department Barium ion qubits are trapped and Doppler cooled in a linear Paul trap and the tasks

Blinov, Boris

276

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

277

Barium Titanate and Bismuth Oxide Nanocomposites Barium titanate, BaTiO3, and bismuth oxide Bi2O3 are transparent materials with  

E-print Network

Barium Titanate and Bismuth Oxide Nanocomposites Barium titanate, BaTiO3, and bismuth oxide Bi2O3 Wall in Tetragonal Barium Titanate", H. Chaib, F. Schlaphof, T. Otto and L. M. Eng, Journal of Physics

Harmon, Julie P.

278

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

279

IRON METABOLISM IN EXPERIMENTAL ANEMIA  

PubMed Central

In experimental anemia in dogs due to blood loss the term "available iron" as determined by the dipyridyl test has no physiological significance. Iron salts (100 per cent available by dipyridyl) given in optimum dose (560 mg. per 2 weeks) will cause a net production of 50 to 55 gm. hemoglobin above the control base line in anemic dogs. This means that an iron salt which is rated as 100 per cent available by the dipyridyl test is only 35 per cent physiologically available. The term "available iron (dipyridyl)" simmers down to iron not in the form of hematin compounds. The absorption of this "available iron" is conditioned by a great variety of factors, many unknown at this time. Iron is indeed an elusive sprite whose "availability" or comings and goings cannot be determined in dogs by dipyridyl—perhaps only in part by studies of absorption and excretion. Liver contains "available iron (dipyridyl)" but also organic factors influencing hemoglobin regeneration in anemia as liver ash contains only about 50 per cent the potency of the whole liver. One can readily dissociate the iron from other potent factors in various tissues. Fractions of heart, liver, spleen, and kidney may contain very little iron yet cause much hemoglobin regeneration in anemic dogs. No investigator has reported any condition of copper deficiency in man or dog. In fact, in anemias copper is usually above normal concentration in the liver. It is unlikely, therefore, that in experimental anemia in dogs and in the various anemias of man, any significance attaches to the intake of copper. PMID:19870718

Hahn, P. F.; Whipple, G. H.

1938-01-01

280

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

281

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

282

Attaching Copper Wires to Magnetic-Reed-Switch Leads  

NASA Technical Reports Server (NTRS)

Bonding method reliably joins copper wires to short iron-alloy leads from glass-encased dry magnetic-reed switch without disturbing integrity of glass-to-metal seal. Joint resistant to high temperatures and has low electrical resistance.

Kamila, Rudolf

1987-01-01

283

Pathogenic adaptations to host-derived antibacterial copper  

PubMed Central

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

Chaturvedi, Kaveri S.; Henderson, Jeffrey P.

2014-01-01

284

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

285

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

286

Copper intrauterine contraceptive devices and serum essential metals  

Microsoft Academic Search

Serum levels of the essential metals, iron (Fe), copper (Cu), magnesium (Mg), zinc (Zn), and calcium (Ca), were determined by atomic absorption spectrophotometry in one hundred and twenty randomly selected adult Nigerian female volunteers fitted with copper T or Delta T intrauterine contraceptive devices (IUDs) for a period of 3–18 months, and their normal age-matched controls. The mean serum concentration

S. O. Ayangade; O. O. Oyelola

1988-01-01

287

Physico-chemical properties of copper electrorefining and electrowinning electrolytes  

NASA Astrophysics Data System (ADS)

Densities, viscosities, electrical conductivities and specific heats of solutions containing copper, nickel, arsenic, iron and sulphuric acid in the concentration ranges of copper electrorefining and electrowinning electrolytes have been measured. Equations are presented for calculating these properties as a function of electrolyte composition and temperature.

Price, Derek C.; Davenport, William G.

1981-12-01

288

Trapped Barium Ions for Quantum ComputationTrapped Barium Ions for Quantum Computation V.Mirgon, G.Shu, A.Avril, M.Dietrich N.Kurz, E. Shahar, and B.B.Blinov  

E-print Network

Trapped Barium Ions for Quantum ComputationTrapped Barium Ions for Quantum Computation V.Mirgon, G of Washington Seattle WA 98195 Trapped Barium Ions for Quantum ComputationTrapped Barium Ions for Quantum

Blinov, Boris

289

Inhibition of copper uptake in yeast reveals the copper transporter Ctr1p as a potential molecular target of saxitoxin  

PubMed Central

Saxitoxin is a secondary metabolite produced by several species of dinoflagellates and cyanobacteria which targets voltage-gated sodium and potassium channels in higher vertebrates. However, its molecular target in planktonic aquatic community members that co-occur with the toxin producers remains unknown. Previous microarray analysis with yeast identified copper and iron-homeostasis genes as being differentially regulated in response to saxitoxin. This study sought to identify the molecular target in microbial cells by comparing the transcriptional profiles of key copper and iron homeostasis genes (CTR1, FRE1, FET3, CUP1, CRS5) in cells exposed to saxitoxin, excess copper, excess iron, an extracellular Cu(I) chelator, or an intracellular Cu(I) chelator. Protein expression and localization of Ctr1p (copper transporter), Fet3p (multicopper oxidase involved in high-affinity iron uptake), and Aft1p (iron regulator) were also compared among treatments. Combined transcript and protein profiles suggested saxitoxin inhibited copper uptake. This hypothesis was confirmed by intracellular Cu(I) imaging with a selective fluorescent probe for labile copper. Based on the combined molecular and physiological results, a model is presented in which the copper transporter Ctr1p serves as a molecular target of saxitoxin and these observations couched in the context of the eco-evolutionary role this toxin may serve for species that produce it. PMID:22304436

Cusick, Kathleen D.; Minkin, Steven C.; Dodani, Sheel C.; Chang, Christopher J.; Wilhelm, Steven W.

2012-01-01

290

A Novel Copper A Containing Menaquinol NO Reductase from Bacillus azotoformans  

E-print Network

A Novel Copper A Containing Menaquinol NO Reductase from Bacillus azotoformans Suharti, Marc J. F of one non-heme iron, two copper atoms and of two b-type hemes per enzyme complex. Heme c was absent features of this enzyme that distinguish it from other NO reductases. First, the enzyme contains copper

Schroeder, Imke

291

COPPER-UPTAKE KINETICS OF COASTAL AND OCEANIC DIATOMS1 , Amber L. Annett3  

E-print Network

COPPER-UPTAKE KINETICS OF COASTAL AND OCEANIC DIATOMS1 Jian Guo2 , Amber L. Annett3 , Rebecca L We investigated copper (Cu) acquisition mecha- nisms and uptake kinetics of the marine diatoms organic Cu complexes. Key index words: copper; Cu; diatom; Fe; iron; kinetics; Thalassiosira; transport

292

Accumulation and hyperaccumulation of copper in plants  

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

293

Ultrafast laser inscription of bistable and reversible waveguides in strontium barium niobate crystals  

E-print Network

Ultrafast laser inscription of bistable and reversible waveguides in strontium barium niobate optical channel waveguides in strontium barium niobate nonlinear ferroelectric crystals by direct barium niobate SBN crystal because of its prime importance in modern photonics due to its nonlinear

294

Enhanced dielectric properties from barium strontium titanate films with strontium titanate buffer layers  

E-print Network

Enhanced dielectric properties from barium strontium titanate films with strontium titanate buffer in their PE state. One of the leading material candidates for tunable materials is barium strontium titanate- tive amounts of Ba and Sr. TC for pure barium t

Alpay, S. Pamir

295

Dielectric properties of MgO-doped compositionally graded multilayer barium strontium titanate films  

E-print Network

Dielectric properties of MgO-doped compositionally graded multilayer barium strontium titanate shifters and filters operat- ing in the microwave regime.1­4 Ferroelectrics FEs such as barium strontium. Required amounts of barium

Alpay, S. Pamir

296

Engineering domain configurations for enhanced piezoelectricity in barium titanate single crystals  

E-print Network

Engineering domain configurations for enhanced piezoelectricity in barium titanate single crystals piezoelectric responses of barium titanate single crystals under different crystallographic orientations, and use it to explain the ultrahigh piezoelectric response recently observed in a 270 cut barium titanate

Li, Jiangyu

297

Production of translationally cold barium monohalide ions  

E-print Network

We have produced sympathetically cooled barium monohalide ions BaX$^+$ (X = F, Cl, Br) by reacting trapped, laser cooled Ba$^+$ ions with room temperature gas phase neutral halogen-containing molecules. Reaction rates for two of these (SF$_6$ and CH$_3$Cl) have been measured and are in agreement with classical models. BaX$^+$ ions are promising candidates for cooling to the rovibrational ground state, and our method presents a straightforward way to produce these polar molecular ions.

DePalatis, M V

2013-01-01

298

Barium ferrite films grown by laser ablation  

Microsoft Academic Search

Pulsed laser ablation (PLA) has been used to grow barium ferrite films on Al2O3 single crystal substrates. When deposition occurs in an oxidising atmosphere at high temperatures, the films are single BaFe12O19 phase, very well oriented with (001) texture, and exhibit a large perpendicular magnetic anisotropy. In this case, the microstructure and the anisotropy orientation are not influenced by variation

A. Lisfia; J. C. Lodder; P. de Haan; M. A. Smithers; F. J. G. Roesthuis

1998-01-01

299

Properties of barium ferrite sputtered films  

Microsoft Academic Search

Ferrites have magnetic properties suitable for electronic applications, especially in the microwave range (circulators and isolators). Hexagonal ferrite, such as barium ferrite (BaFe12O19 or BaM), are of great interest for microwave device applications because of their large resistivity and high permeability at high frequencies. BaM films, 1–10?m thick, were deposited under optimized conditions by RF magnetron sputtering on alumina and

S. Capraro; M. Le Berre; J. P. Chatelon; H. Joisten; E. Mery; B. Bayard; J. J. Rousseau; D. Barbier

2004-01-01

300

Pyroelectroluminescence of barium beta borate single crystals  

Microsoft Academic Search

Investigations were made of the pyroluminescence properties of barium beta borate single crystals. The measurements were made\\u000a at air pressures of 1–10 Pa and temperatures of 80–400 K. Luminescence was observed as isolated flashes over the entire range\\u000a of experimental conditions. It was observed that the light flashes coincided with the pyrocurrent oscillations.

V. T. Adamiv; Ya. V. Burak; M. R. Panasyuk; I. M. Teslyuk

1998-01-01

301

Electronic structure of nanograin barium titanate ceramics  

Microsoft Academic Search

The density of states and band structure of 20 nm barium titanate (BaTiO3, BT) ceramics are investigated by first-principles calculation. The full potential linearized augmented plane wave (FLAPW)\\u000a method is used and the exchange correlation effects are treated by the generalized gradient approximation (GGA). The results\\u000a show that there is substantial hybridization between the Ti 3d and O 2p states

Xiangyun Deng; Xiaohui Wang; Dejun Li; Longtu Li

2007-01-01

302

Resonance-fluorescence in barium ion clouds  

NASA Astrophysics Data System (ADS)

The problem of resonant-fluorescent scattering of sunlight by a high altitude, plane-parallel, barium ion cloud is solved numerically. Line strengths and profiles are computed using a modified version of the computer program LINEAR (Auer, Heasley and Milkey, 1972). Hyperfine structure of the spectral lines becomes important for very thick layers and is taken into account. Comparisons are made between coherent and completely noncoherent scattering results, and finally the influence of collisions on the radiation field is estimated.

Horak, H. G.; Whitaker, R. W.

1982-09-01

303

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

304

Fabrication of Barium Ferrite Thick Films  

NASA Astrophysics Data System (ADS)

During recent years the need for high quality self-biased barium ferrite (BaFe12O19) thick films had been increasing due to its chemical stability, anisotropy and oriented hexagonal M-type ferrites. Our goal is to fabricate barium ferrite thick films to be incorporated in self-biased microwave devises. Different methods such as sputtering, pulse laser deposition, CVD and modified liquid phase deposition have been used for thick film deposition with limited or no success for thickness above 300?m. Excessive residual stresses of BaM films deposited with the previous methods and/or their low coercivity are the main problems targeted by this project. We present a low cost solution using BaFe12O19 nanopowder mixing with epoxy. The mix is placed on alumina substrates to fabricate 500?m thick films of BaM, resulting thick films with good magnetic properties such as a 4?Ms between 2.000 to 2.500 Gauss and a coercivity of 3800 to 4000 Oe. In addition, we have integrated the barium ferrite thick films into microwave devises and successfully deposited their contact lines for their testing and use.

Jiang Yeh, Wei; Blengeri-Oyarce, Carla; Pillamari, Sundeep; Manoj Appikonda, Jnana; Diaz, Laura; Kranov, Yanko; McIlroy, David

2008-05-01

305

Creating unstable velocity-space distributions with barium injections  

NASA Technical Reports Server (NTRS)

Ion velocity-space distributions resulting from barium injections from orbiting spacecraft and shaped charges are discussed. Active experiments confirm that anomalous ionization processes may operate, but photoionization accounts for the production of the bulk of the barium ions. Pitch-angle diffusion and/or velocity-space diffusion may occur, but observations of barium ions moving upwards against gravity suggests that the ions retain a significant enough fraction of their initial perpendicular velocity to provide a mirror force. The barium ion plasmas should have a range of Alfven Mach numbers and plasma betas. Because the initial conditions can be predicted these active experiments should permit testing plasma instability hypotheses.

Pongratz, M. B.

1983-01-01

306

Spatial and temporal zoning of hydrothermal alteration and mineralization in the Sossego iron oxide-copper-gold deposit, Caraja??s Mineral Province, Brazil: Paragenesis and stable isotope constraints  

USGS Publications Warehouse

The Sossego iron oxide-copper-gold deposit (245 Mt 1.1% Cu, 0.28 g/t Au) in the Caraja??s 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 Itacaiu??nas 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 ??18OH2O 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 ??18OH2O values suggest that the fluids that formed the early calcic-sodic alteration assemblage were of formational/metamorphic or magmatic origin. The decrease of ??18OH2O 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. ?? Springer-Verlag 2007.

Monteiro, L.V.S.; Xavier, R.P.; Carvalho, E.R.; Hitzman, M.W.; Johnson, C.A.; Souza, Filho C.R.; Torresi, I.

2008-01-01

307

Extraction of copper from an oxidized (lateritic) ore using bacterially catalysed reductive dissolution.  

PubMed

An oxidized lateritic ore which contained 0.8 % (by weight) copper was bioleached in pH- and temperature-controlled stirred reactors under acidic reducing conditions using pure and mixed cultures of the acidophilic chemolithotrophic bacterium Acidithiobacillus ferrooxidans. Sulfur was provided as the electron donor for the bacteria, and ferric iron present in goethite (the major ferric iron mineral present in the ore) acted as electron acceptor. Significantly more copper was leached by bacterially catalysed reductive dissolution of the laterite than in aerobic cultures or in sterile anoxic reactors, with up to 78 % of the copper present in the ore being extracted. This included copper that was leached from acid-labile minerals (chiefly copper silicates) and that which was associated with ferric iron minerals in the lateritic ore. In the anaerobic bioreactors, soluble iron in the leach liquors was present as iron (II) and copper as copper (I), but both metals were rapidly oxidized (to iron (III) and copper (II)) when the reactors were aerated. The number of bacteria added to the reactors had a critical role in dictating the rate and yield of copper solubilised from the ore. This work has provided further evidence that reductive bioprocessing, a recently described approach for extracting base metals from oxidized deposits, has the potential to greatly extend the range of metal ores that can be biomined. PMID:24687752

Nancucheo, Ivan; Grail, Barry M; Hilario, Felipe; du Plessis, Chris; Johnson, D Barrie

2014-07-01

308

Oxidation Potentials in Matte Smelting of Copper and Nickel  

NASA Astrophysics Data System (ADS)

The oxidation potential, given as the base-ten logarithm of the oxygen partial pressure in bars and the temperature [log pO2/ T, °C], defines the state of oxidation of pyrometallurgical extraction and refining processes. This property varies from copper making, [-6/1150]; to lead/zinc smelting, [-10/1200]; to iron smelting, [-13/1600]. The current article extends the analysis to the smelting of copper and nickel/copper sulfide concentrates to produce mattes of the type Cu(Ni)FeS(O) and iron silicate slags, FeOxSiO2—with oxidation potentials of [-7.5/1250].

Matousek, Jan W.

2014-09-01

309

Effect of 3d-transition metal doping on the shielding behavior of barium borate glasses: A spectroscopic study  

NASA Astrophysics Data System (ADS)

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 60 mol.%) reveals strong charge transfer UV absorption bands which are related to unavoidable trace iron impurities (Fe3+) 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 580 nm. 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.

ElBatal, H. A.; Abdelghany, A. M.; Ghoneim, N. A.; ElBatal, F. H.

2014-12-01

310

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

311

Characteristics and antimicrobial activity of copper-based materials  

NASA Astrophysics Data System (ADS)

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

Li, Bowen

312

Microbial iron management mechanisms in extremely acidic environments: comparative genomics evidence for diversity and versatility  

Microsoft Academic Search

BACKGROUND: Iron is an essential nutrient but can be toxic at high intracellular concentrations and organisms have evolved tightly regulated mechanisms for iron uptake and homeostasis. Information on iron management mechanisms is available for organisms living at circumneutral pH. However, very little is known about how acidophilic bacteria, especially those used for industrial copper bioleaching, cope with environmental iron loads

Héctor Osorio; Verónica Martínez; Pamela A Nieto; David S Holmes; Raquel Quatrini

2008-01-01

313

Simultaneous determination of arsenic, cadmium, calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, molybdenum, nickel, selenium, and zinc in fertilizers by microwave acid digestion and inductively coupled plasma-optical emission spectrometry detection: single-laboratory validation of a modification and extension of AOAC 2006.03.  

PubMed

A single-laboratory validation study was conducted for the simultaneous determination of arsenic, cadmium, calcium, cobalt, copper, chromium, iron, lead, magnesium, manganese, molybdenum, nickel, selenium, and zinc in all major types of commercial fertilizer products by microwave digestion and inductively coupled plasma-optical emission spectroscopy analysis. This validation study proposes an extension and modification of AOAC 2006.03. The extension is the inclusion of calcium, copper, iron, magnesium, manganese, and zinc, and the modification is incorporation of hydrochloric acid in the digestion system. This dual acid digestion utilizes both hydrochloric and nitric acids in a 3 to 9 mL volume ratio/100 mL. In addition to 15 of the 30 original validation materials used in the 2006.03 collaborative study, National Institute of Standards and Technology Standard Reference Material 695 and Magruder 2009-06 were incorporated as accuracy materials. The main benefits of this proposed method are a significant increase in laboratory efficiency when compared to the use of both AOAC Methods 965.09 and 2006.03 to achieve the same objective and an enhanced recovery of several metals. PMID:25051614

Webb, Sharon; Bartos, James; Boles, Rhonda; Hasty, Elaine; Thuotte, Ethel; Thiex, Nancy J

2014-01-01

314

Studies in reduction-roast leaching ion exchange of copper converter slag from an Indian copper complex, Ghatshila  

SciTech Connect

Large quantities of converter and anode slags are generated in different unit operations for the production of copper in I.C.C. Ghatshila. The converter slag contains about 2.75% copper, 0.9% nickel, 52.0% iron, and 0.6% cobalt and cannot be rejected due to its economic importance. X-ray diffraction (XRD) studies revealed the presence of copper in elemental, oxide, and silicate phases and iron in silicate (Feyalite) and oxide (Fe{sub 2}O{sub 3}) phases. From the earlier work on leaching by an acetic acid lixiviant up to 55% copper could be extracted at 250 mL of acetic acid/100 g of slag, 125 C temperature, and 35 atm of oxygen pressure. Low copper recovery was attributed to the presence of copper silicate and sulfide phases which could not be detected by XRD. Therefore, reduction roasting by noncoking coal was done to increase the copper recovery. A coal sample from Talchar which contained 30% fixed carbon, 40% volatile, and 30% ash was used for reduction roasting. Maximum percent extraction of copper and nickel (97% Cu and 20% Ni) could be achieved at the temperature of 720 C for 90 min of roasting with 20% reductant. The acetic acid requirement was 130 mL/100 g of reduced pellets, while leaching at the oxygen pressure of 35 atm for 120 min at 120 C. Iron dissolution was minimum (max 1%) in all the experiments. The ion-exchange technique was employed to separate copper from acetate solution. Zeolite resin was found to be suitable for the separation of copper from leach liquor. About 92% copper was recovered by geolite. 2.5 N H{sub 2}SO{sub 4} was found to be most effective for the stripping of the copper from resin.

Bodas, M.G.; Mathur, S.B. [National Metallurgical Lab., Jamshedpur (India). Non-Ferrous Process Div.] [National Metallurgical Lab., Jamshedpur (India). Non-Ferrous Process Div.

1997-12-01

315

Copper peroxide  

NASA Technical Reports Server (NTRS)

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

Moser, L.

1988-01-01

316

COPPER AND BRAIN FUNCTION  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

317

Effect of Different Weight Fraction on Dielectric Properties of Barium Ferrite-Barium Titanate Composites  

NASA Astrophysics Data System (ADS)

Barium ferrite-barium titanate composite systems, (1-x)BaFe12O19 - (x)BaTiO3 with different weight fractions of × = 0.0, 0.1, 0.3 and 0.5 were prepared via the conventional solid state reaction method using nano-sized starting materials. The x-ray diffraction peaks of the composite samples show two phases which can be indexed by the hexagonal barium ferrite and tetragonal barium titanate. Field emission scanning electron microscope (FESEM) image of sample with × = 0.1 shows formation of nano-sized BaTiO3 grains spreading evenly among the micron-sized BaFe12O19 grains after sintering at 1000 °C. The dielectric properties studies at room temperature of the composites samples show that sample with BaTiO3 weight fraction of × = 0.1 has the highest dielectric constant, ?' and lowest loss tangent, tan ? in the studied frequency range between 1 Hz and 1 MHz. Its highest dielectric constant value is ~ 1.2 × 103 and its lowest loss tangent is 0.06 at 50 Hz.

Anuar, S. N.; Zalita, Z.; Shamsudin, R.

2013-04-01

318

Thermal decomposition of (BaTi) citrates into barium titanate  

Microsoft Academic Search

From aqueous solutions of barium and titanium citrates two different (BaTi) citrate salts can be precipitated, depending on the pH of the solution. The ratio of barium to titanium in the salts is either 1 : 1 or 2 : 1. The thermal decomposition of the salts was investigated by means of DTA, TGA, infrared spectroscopy, and X-ray diffraction. At

D. Hennings; W. Mayr

1978-01-01

319

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...

320

Spectroscopic studies of novel porphyrin-copper(II) and zinc(II) complexes that share the pinch-porphyrin family structure of iron(III) complex models of peroxidases  

Microsoft Academic Search

Six novel pinch-porphyrin complexes [(picdien)(protoporphyrinate dimethyl ester)]copper(II) (7), [(picdien)(mesoporphyrinate dimethyl ester)]copper(II) (8) and [(picdien)(deuteroporphyrinate dimethyl ester)]copper(II) (9), [(picdien)(protoporphyrinate dimethyl ester)]zinc(II) (13), [(picdien)(mesoporphyrinate dimethyl ester)]zinc(II) (14) and [(picdien)(deuteroporphyrinate dimethyl ester)]zinc(II) (15), were prepared from the corresponding free copper(II)-porphyrins (4–6), and zinc(II)-porphyrins (10–12) and picdien (N-(3H-imidazol-4-ylmethyl)-N'-{2-[(3H-imidazol-4-ylmethyl)-amino]-ethyl}-ethane-2,3-diamine). Spectroscopic studies show that complexes (7–9) and (13–15) have the pinch-porphyrin type structure previously found in

José Luis Gárate-Morales; Yasmi Reyes-Ortega; Cecilio Alvarez-Toledano; René Gutiérrez-Pérez; Daniel Ramírez-Rosales; Rafael Zamorano-Ulloa; Eduardo Basurto-Uribe; Julio Hernández-Díaz; Rosalinda Contreras

2002-01-01

321

Proper management for morbid iatrogenic retroperitoneal barium insufflation.  

PubMed

A barium enema is a diagnostic and therapeutic procedure commonly used for colon and rectum problems. Rectal perforation with extensive intra- and/or extraperitoneal spillage of barium is a devastating complication of a barium enema that leads to a significant increase in patient mortality. Due to the low number of reported cases in recent scientific literature and the lack of experience with the management of these cases, we would like to present our treatment approach to a rare case of retroperitoneal contamination with barium, followed by its intraperitoneal involvement during a diagnostic barium enema. Our experience with long-term management of the patient and the good outcome will be depicted in this paper. PMID:25580416

Vahedian-Ardakani, Jalal; Nazerani, Shahram; Saraee, Amir; Sarmast, Ali; Saraee, Ehsan; Keramati, Mohammad Reza

2014-12-01

322

Proper Management for Morbid Iatrogenic Retroperitoneal Barium Insufflation  

PubMed Central

A barium enema is a diagnostic and therapeutic procedure commonly used for colon and rectum problems. Rectal perforation with extensive intra- and/or extraperitoneal spillage of barium is a devastating complication of a barium enema that leads to a significant increase in patient mortality. Due to the low number of reported cases in recent scientific literature and the lack of experience with the management of these cases, we would like to present our treatment approach to a rare case of retroperitoneal contamination with barium, followed by its intraperitoneal involvement during a diagnostic barium enema. Our experience with long-term management of the patient and the good outcome will be depicted in this paper. PMID:25580416

Vahedian-Ardakani, Jalal; Nazerani, Shahram; Saraee, Amir; Sarmast, Ali; Saraee, Ehsan

2014-01-01

323

Barium Enhancement in NGC 6819 Blue Stragglers  

NASA Astrophysics Data System (ADS)

Possible formation pathways for blue straggler stars include mergers in hierarchical triple systems, stellar collisions during dynamical encounters, and mass transfer from a giant companion. Extensive work on the blue stragglers in the old open cluster NGC 188 (7 Gyr) has led to exciting discoveries including a binary secondary mass distribution peaked at 0.5 MSolar and the detection of three young white dwarf binary companions. These indicate that mass transfer from an asymptotic giant branch star is the dominant mechanism for blue straggler formation in open clusters. Such mass transfer events should pollute the surface abundance of the blue straggler with nucleosynthesis products from the evolved donor. The other formation pathways, mergers and collisions, are predicted to produce no such enhancements. In an effort to move beyond NGC 188 and into other open clusters we present the first results of a surface abundance study of the blue stragglers in the intermediate-aged open cluster NGC 6819 (2.5 Gyr) using the Hydra multi-object spectrograph on the WIYN 3.5 m telescope. This part of our study centers on the s-process element barium as a tracer of formation via mass transfer. We compare the blue straggler surface abundance of barium to that of a sample of main-sequence stars in NGC 6819 and find multiple blue stragglers with anomalous abundances. Surprising, most of the blue stragglers with barium anomalies show no radial-velocity evidence for a companion. We gratefully acknowledge funding from the National Science Foundation under grant AST- 0908082 and the Wisconsin Space Grant Consortium.

Milliman, Katelyn; Mathieu, Robert D.; Schuler, Simon C.

2015-01-01

324

Scattering lengths of calcium and barium isotopes  

E-print Network

We have calculated the s-wave scattering length of all the even isotopes of calcium (Ca) and barium (Ba), in order to investigate the prospect of Bose-Einstein condensation (BEC). For Ca we have used an accurate molecular potential based on detailed spectroscopic data. Our calculations show that Ca does not provide other isotopes alternative to the recently Bose condensed 40Ca that suffers strong losses because of a very large scattering length. For Ba we show by using a model potential that the even isotopes cover a broad range of scattering lengths, opening the possibility of BEC for at least one of the isotopes.

U. Dammalapati; L. Willmann; S. Knoop

2011-10-25

325

Short-cavity squeezing in barium  

NASA Technical Reports Server (NTRS)

Broadband phase sensitive noise and squeezing were experimentally observed in a system of barium atoms interacting with a single mode of a short optical cavity. Squeezing of 13 +/- 3 percent was observed. A maximum possible squeezing of 45 +/- 8 percent could be inferred for out experimental conditions, after correction for measured loss factors. Noise reductions below the quantum limit were found over a range of detection frequencies 60-170 MHz and were best for high cavity transmission and large optical depths. The amount of squeezing observed is consistent with theoretical predictions from a full quantum statistical model of the system.

Hope, D. M.; Bachor, H-A.; Manson, P. J.; Mcclelland, D. E.

1992-01-01

326

Current-voltage characteristics of barium polymethacrylate  

SciTech Connect

In this paper current-voltage characteristics of Barium Polymethacrylate (BaPMA) in the form of Al-BaPMA-Al structures are studied. The currents are measured in the voltage range 10 V-1 kV. At low voltages an ohmic relation is observed and at higher voltages the Poole-Frenkel mechanism is proposed. The mechanism of conduction has been explained on the basis of different current-voltage and current-temperature curves. The activation energy values calculated using Arrhenius relation fall in the range 0.25-2 eV, suggesting a sequence of trapping levels.

Chohan, M.H. (Lab. for Electrical Characterization of Polymers, Dept. of Electronics, Quaid-i-Azam Univ., Islamabad (PK)); Zulfiqar, M.; Sapra, Z.H.; Husain, R.; Zulfiqar, S. (Dept. of Chemistry, Quaid-i-Azam Univ., Islamabad (PK))

1992-06-30

327

Scattering lengths of calcium and barium isotopes  

SciTech Connect

We have calculated the s-wave scattering length of all the even isotopes of calcium (Ca) and barium (Ba) in order to investigate the prospect of Bose-Einstein condensation (BEC). For Ca we have used an accurate molecular potential based on detailed spectroscopic data. Our calculations show that Ca does not provide other isotopes alternative to the recently Bose condensed {sup 40}Ca that suffers strong losses because of a very large scattering length. For Ba we show by using a model potential that the even isotopes cover a broad range of scattering lengths, opening the possibility of BEC for at least one of the isotopes.

Dammalapati, U.; Willmann, L.; Knoop, S. [Kernfysisch Versneller Instituut (KVI), University of Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands); LaserLaB Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam (Netherlands)

2011-11-15

328

Lab Tracker and Copper Calculator  

MedlinePLUS

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

329

308 Brain Research, 498 (1989) 308-314 Potassium conductance block by barium in amphibian  

E-print Network

308 Brain Research, 498 (1989) 308-314 Elsevier BRES 14831 Potassium conductance block by barium cell; Glial cell; Retina; Barium; Potassium conductance; Tiger salamander The effect of barium on M in situ (retinal slice and isolated retina). Barium effects were similar in both cases. In dissociated

Newman, Eric A.

330

Fluid seepage along the San Clemente Fault scarp: basin-wide impact on barium cycling  

E-print Network

Fluid seepage along the San Clemente Fault scarp: basin-wide impact on barium cycling Marta E present evidence that the barium released at cold seeps along the San Clemente Fault zone may significantly impact the geochemical budget of barium within the basin. Barium fluxes at seep localities

Huh, Chih-An

331

Cation non-stoichiometry in yttrium-doped barium zirconate: phase behavior, microstructure, and proton conductivity  

E-print Network

Cation non-stoichiometry in yttrium-doped barium zirconate: phase behavior, microstructure approach in which the barium deficiency is precisely controlled. The perovskite phase is tolerant to barium-phase region barium deficiency also has a detrimental impact on grain boundary conductivity, as a result both

332

Earthquake-induced barium anomalies in the Lisan Formation, Dead Sea Rift valley, Israel  

E-print Network

Earthquake-induced barium anomalies in the Lisan Formation, Dead Sea Rift valley, Israel Amitai Editor: L. Stixrude Keywords: barium Dead Sea seismite earthquake Lisan recurrence rate Prominent barium The present paper is a rst report of prominent barium concen- tration anomalies in seismically perturbed

Marco, Shmuel "Shmulik"

333

Barium ion Zeeman and space potential diagnostic  

NASA Astrophysics Data System (ADS)

A diagnostic has been developed to simultaneously determine the magnetic field and space potential in fusion-like plasmas.1 In Fig. 1, we show schematically the diagnostic concept. The magnetic field is determined by a measurement of the Zeeman resonance absorption pattern of an energetic (<30 keV) barium ion beam (10 ?A). The spectrum is obtained by laser-induced fluorescence. In our approach, similar to a technique developed at UC Irvine,2 the absorption spectrum of the barium ion beam is measured as the frequency of a narrow-linewidth dye laser is scanned over the Doppler-shifted Zeeman-split resonance transition. The resonantly scattered light at 4934.1 Å is collected without frequency processing other than a narrow-band filter to reduce background plasma light. Space potentials are determined by a measurement of the Doppler shift due to a change in beam energy, E=E0-e?p(E0 is the beam energy, ?p is the plasma potential). The laser is injected tangentially to the ion beam to take advantage of the narrow Doppler spread in the direction of the beam.

Wickham, M.; Lazar, N. H.; Rynn, N.

1985-05-01

334

Cyanobacterial metallochaperone inhibits deleterious side reactions of copper  

PubMed Central

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

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

2012-01-01

335

Transition-metal prion protein attachment: Competition with copper  

NASA Astrophysics Data System (ADS)

Prion protein, PrP, is a protein capable of binding copper ions in multiple modes depending on their concentration. Misfolded PrP is implicated in a group of neurodegenerative diseases, which include ``mad cow disease'' and its human form, variant Creutzfeld-Jacob disease. An increasing amount of evidence suggests that attachment of non-copper metal ions to PrP triggers transformations to abnormal forms similar to those observed in prion diseases. In this work, we use hybrid Kohn-Sham/orbital-free density functional theory simulations to investigate copper replacement by other transition metals that bind to PrP, including zinc, iron and manganese. We consider all known copper binding modes in the N-terminal domain of PrP. Our calculations identify modes most susceptible to copper replacement and reveal metals that can successfully compete with copper for attachment to PrP.

Hodak, Miroslav; Bernholc, Jerry

2012-02-01

336

Toxicity of Copper and Ascorbic Acid to Serratia marcescens  

PubMed Central

Zimmerman, Leonard (Fort Detrick, Frederick, Md.). Toxicity of copper and ascorbic acid to Serratia marcescens. J. Bacteriol. 91:1537–1542. 1966.—Neutral solutions of ascorbic acid were antibacterial to Serratia marcescens at low but not at high population densities. The toxicity of ascorbate was eliminated by metal-sequestering treatments, and was restored only by the addition of trace amounts of copper salts. Copper-ascorbate was equally toxic under aerobic or anaerobic conditions; its toxicity was abolished by (i) chelating agents that sequestered the copper, (ii) metal-complexing agents that bound to the cells but did not sequester copper, and (iii) iron salts in the presence of air. On the basis of these observations, the toxic effects of copper-ascorbate were attributed to its reaction with vital Fe-containing cellular components. PMID:5326115

Zimmerman, Leonard

1966-01-01

337

Role of copper transporters in copper homeostasis.  

PubMed

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

Prohaska, Joseph R

2008-09-01

338

Do all barium stars have a white dwarf companion?  

NASA Technical Reports Server (NTRS)

International Ultraviolet Explorer short-wavelength, low-dispersion spectra were analyzed for four barium, two mild barium, and one R-type carbon star in order to test the hypothesis that the barium and related giants are produced by mass transfer from a companion now present as a white dwarf. An earlier tentative identification of a white dwarf companion to the mild barium star Zeta Cyg is confirmed. For the other stars, no ultraviolet excess attributable to a white dwarf is seen. Limits are set on the bolometric magnitude and age of a possible white dwarf companion. Since the barium stars do not have obvious progenitors among main-sequence and subgiant stars, mass transfer must be presumed to occur when the mass-gaining star is already on the giant branch. This restriction, and the white dwarf's minimum age, which is greater than 8 x 10 to the 8th yr, determined for several stars, effectively eliminates the hypothesis that mass transfer from an asymptotic giant branch star creates a barium star. Speculations are presented on alternative methods of producing a barium star in a binary system.

Dominy, J. F.; Lambert, D. L.

1983-01-01

339

[Ceruloplasmin, hephaestin and zyklopen: the three multicopper oxidases important for human iron metabolism].  

PubMed

Multi-copper oxidases are a group of proteins which demonstrate enzymatic activity and are capable of oxidizing their substrates with the concomitant reduction of dioxygen to two water molecules. For some multi-copper oxidases there has been demonstrated ferroxidase activity which is related to their specific structure characterized by the presence of copper centres and iron-binding sites. Three multi-copper oxidases have been included in this group: ceruloplasmin, hephaestin and zyklopen. Multi-copper oxidases which are expressed in different tissues are capable of oxidizing a wide spectrum of substrates. Multi-copper oxidases are capable of oxidizing a wide spectrum of substrates. Ceruloplasmin exhibits antioxidant activity as well as being involved in many other biological processes. The observations of phenotypic effects of absence or low expression of multi-copper ferroxidase-coding genes suggest that the main role of these proteins is taking part in iron metabolism. The main role of ceruloplasmin in iron turnover is oxidizing Fe2+ into Fe3+, a process which is essential for iron binding to transferrin (the main iron-transporting protein), as well as to ferritin (the main iron-storage protein). The function of hephaestin as ferroxidase is essential for iron binding to apotransferrin in the lamina propria of the intestinal mucosa, a process that is important for further transport of iron to the liver by the portal vein. Available data indicate that zyklopen is responsible for the placental iron transport. The presence of three multi-copper oxidases with ferroxidase activity emphasizes the significance of oxidation for iron metabolism. The distribution of multi-copper ferroxidases in many tissues ensures the proper iron turnover in the body as well as preventing toxic effects related to the presence of Fe2+ ions. These ions contribute to generation of free radicals, including the highly reactive hydroxyl radical, through the Fenton and Haber-Weiss reactions. PMID:24988611

Wierzbicka, Diana; Gromadzka, Grazyna

2014-01-01

340

Simultaneous amperometric determination of nickel and copper.  

PubMed

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

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

1975-06-01

341

A high-altitude barium radial injection experiment  

NASA Technical Reports Server (NTRS)

A rocket launched from Poker Flat, Alaska, carried a new type of high-explosive barium shaped charge to 571 km, where detonation injected a thin disk of barium vapor with high velocity nearly perpendicular to the magnetic field. The TV images of the injection are spectacular, revealing three major regimes of expanding plasma which showed early instabilities in the neutral gas. The most unusual effect of the injection is a peculiar rayed barium-ion structure lying in the injection plane and centered on a 5 km 'black hole' surrounding the injection point. Preliminary electrostatic computer simulations show a similar rayed development.

Wescott, E. M.; Stenbaek-Nielsen, H. C.; Hallinan, T. J.; Deehr, C. S.; Romick, G. J.; Olson, J. V.; Roederer, J. G.; Sydora, R.

1980-01-01

342

Eat Iron?!!  

NSDL National Science Digital Library

To gain an understanding of mixtures and the concept of separation of mixtures, students use strong magnets to find the element of iron in iron-fortified breakfast cereal flakes. Through this activity, they see how the iron component of this heterogeneous mixture (cereal) retains its properties and can thus be separated by physical means.

NSF GK-12 and Research Experience for Teachers (RET) Programs,

343

Radium and barium removal through blending hydraulic fracturing fluids with acid mine drainage.  

PubMed

Wastewaters generated during hydraulic fracturing of the Marcellus Shale typically contain high concentrations of salts, naturally occurring radioactive material (NORM), and metals, such as barium, that pose environmental and public health risks upon inadequate treatment and disposal. In addition, fresh water scarcity in dry regions or during periods of drought could limit shale gas development. This paper explores the possibility of using alternative water sources and their impact on NORM levels through blending acid mine drainage (AMD) effluent with recycled hydraulic fracturing flowback fluids (HFFFs). We conducted a series of laboratory experiments in which the chemistry and NORM of different mix proportions of AMD and HFFF were examined after reacting for 48 h. The experimental data combined with geochemical modeling and X-ray diffraction analysis suggest that several ions, including sulfate, iron, barium, strontium, and a large portion of radium (60-100%), precipitated into newly formed solids composed mainly of Sr barite within the first ? 10 h of mixing. The results imply that blending AMD and HFFF could be an effective management practice for both remediation of the high NORM in the Marcellus HFFF wastewater and beneficial utilization of AMD that is currently contaminating waterways in northeastern U.S.A. PMID:24367969

Kondash, Andrew J; Warner, Nathaniel R; Lahav, Ori; Vengosh, Avner

2014-01-21

344

Designed microstructures in textured barium hexaferrite  

NASA Astrophysics Data System (ADS)

It is a fundamental principle of materials science that the microstructure of a material defines its properties and ultimately its performance for a given application. A prime example of this can be found in the large conch shell Strombus gigas, which has an intricate microstructure extending across five distinct length scales. This microstructure gives extraordinary damage tolerance to the shell. The structure of Strombus gigas cannot be replicated in a modern engineering ceramic with any existing processing technique, so new processing techniques must be developed to apply this structure to a model material. Barium hexaferrite was chosen as a model material to create microstructures reminiscent of Strombus gigas and evaluate its structure-property relations. This work describes novel processing methods to produce textured barium hexaferrite with no coupling between the sample geometry and the texture direction. This technique, combining magnetic field-assisted gelcasting with templated grain growth, also allows multilayer samples to be fabricated with different texture directions in adjacent layers. The effects of adding either B2O3 or excess BaCO 3 on the densification and grain growth of barium hexaferrite was studied. The texture produced using this technique was assessed using orientation imaging microscopy (OIM) at Oak Ridge National Laboratory. These measurements showed peak textures as high as 60 MRD and sharp interfaces between layers cast with different texture directions. The effect of oxygen on the quality of gelcasting is also discussed, and it is shown that with proper mold design, it is possible to gelcast multiple layers with differing texture directions without delamination. Monolithic and multilayer samples were produced and tested in four point bending to measure the strength and work of fracture. Modulus measurements, made with the ultrasonic pulse-echo technique, show clear signs of microcracking in both the isotropic and textured samples. Both the strength and work of fracture were shown to be affected by the texture direction. The multilayer samples did not show significant improvements in either strength or work of fracture, but they did show much less variability than the monolithic samples.

Hovis, David Brian

345

Impact of Copper Limitation on Expression and Function of Multicopper Oxidases (Ferroxidases)12  

PubMed Central

Copper is an essential trace element whose recommended intake is met by most North American diets. However, incidence of new cases of secondary copper deficiency is rising due to complications of gastric bypass surgery and high zinc exposure. Patients frequently are ataxic and anemic. Anemia of copper deficiency was first described in the 19th century, but the underlying biochemistry remains unknown. Approximately one dozen cuproenzymes have been characterized in mammals. Four of these are referred to as multicopper oxidases (MCO) due to their copper binding geometries. They have iron oxidase activity (ferroxidase). These include the hepatic secreted protein ceruloplasmin representing ?90% of plasma copper, a splice-variant of ceruloplasmin originally characterized in brain linked by glycosylphosphatidylinositol (GPI) to membranes, an intestinal enriched MCO named hephaestin, and newly described MCO in placenta called zyklopen. Limitation in available copper appears to limit function of the MCO group exhibited as impaired iron flux due to the copper requirement of MCO for their ferroxidase activity. Dietary copper deficiency is associated with lower levels of ceruloplasmin, GPI-ceruloplasmin, and hephaestin. Limitation of copper does not appear to limit synthesis of MCO but rather their stability and turnover. However, there appears to be a disconnect between limitation in MCO function and anemia, because humans and mice missing ceruloplasmin are not anemic despite hepatic iron overload and hypoferremia. Furthermore, anemic copper-deficient mammals are not improved by iron replacement. This suggests that the anemia of copper deficiency is not caused by iron limitation but rather impairment in iron utilization. PMID:22332037

Prohaska, Joseph R.

2011-01-01

346

Iron Nanoparticles in Reactive Environmental Barriers  

SciTech Connect

Zero-valent iron is cheap, environmentally innocuous, and effective at reducing chlorinated organics. It has, as a result, become a popular candidate for remediating aquifers contaminated with trichloroethylene and other halogenated pollutants. In this paper, we discuss one such system, where iron nanoparticles are synthesized and incorporated into polyvinyl alcohol membranes, forming water-permeable barriers to these pollutants. These barriers are tested against a variety of contaminants, including carbon tetrachloride, copper, and chromate.

Nuxoll, Eric E.; Shimotori, Tsutomu; Arnold, William A.; Cussler, Edward L.

2003-09-23

347

COPPER CORROSION RESEARCH UPDATE  

EPA Science Inventory

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

348

Phased surgical treatment of barium enema-induced rectal injury and retention of barium in the pelvic floor space  

PubMed Central

Iatrogenic injuries caused by barium enema are rarely reported. Following a phased surgical protocol for up to one year, we have successfully treated a patient with rectal injury and severe infection of the pelvic floor space complicated with retention of large amounts of barium and vaginal fistula. In this article, the phased surgery planning for the treatment of rectal injury complicated with vaginal fistula is discussed in terms of the pros and cons, and the observed effect and evolution of barium retained in the pelvic floor space are described. PMID:25405155

Yang, Xuefei; Xia, Ligang; Huang, Jun; Wang, Jianping

2014-01-01

349

Theoretical isotope shifts in neutral barium  

E-print Network

The present work deals with a set of problems in isotope shifts of neutral barium spectral lines. Some well known transitions ($6s^2~^1S_0-6s6p~^{1,3}P^o_1$ and $6s^2~^1S_0-6p^2~^3P_0$) are first investigated. Values of the changes in the nuclear mean-square charge radius are deduced from the available experimental isotope shifts using our ab initio electronic factors. The three sets $\\{ \\delta\\langle r^2\\rangle^{A,A'}\\} $ obtained from these lines are consistent with each other. The combination of the available nuclear mean-square radii with our electronic factors for the $6s5d~^3D_{1,2} -6s6p~^{1}P^o_1$ transitions produces isotope shift values in conflict with the laser spectroscopy measurements of Dammalapati et al. (Eur. Phys. J. D 53, 1 (2009)).

Nazé, Cédric; Godefroid, Michel

2015-01-01

350

Synthesis and characterization of barium hexagonal ferrite  

NASA Astrophysics Data System (ADS)

Barium Hexagonal ferrite (BaFe12O19) was synthesized by a two step process, first by high-energy ball milling and then sintering the milled powder subsequently at 950°C. The phase formation and morphology studies were carried out using X-ray Diffraction (XRD) and High Resolution Scanning Electron Microscopy (HRSEM) respectively. XRD results clearly show the phase purity and the good crystalline nature of BaFe12O19. The mean particle size was found to be 80 nm from the SEM image. The magnetic properties such as saturation magnetization and coercive field were calculated from the magnetization curve, which was obtained using Vibrating Sample Magnetometer (VSM). A possible relation between the magnetic hysteresis curve and the microstructure of the sintered sample has been investigated.

Manikandan, M.; Venkateswaran, C.

2013-02-01

351

Magnetic properties of substituted barium ferrite powders  

SciTech Connect

Hexagonal barium ferrites were prepared using the citrate method. Cobalt and titanium were added in the amounts x from 0.2 to 1.1 ion/f.u. related to the formula BaCo{sub x}Ti{sub x}Fe{sub 12{minus}2x}O{sub 19}. The heat treatment has been applied in three steps of 550 C/5 hrs, 850 C/2 hrs and 1,100 C/2 hrs. The following magnetic properties have been achieved: H{sub c} {approximately} 80 kA/m, J{sub s} {approximately} 120 {times} 10{sup {minus}6} Tkg{sup {minus}1} m{sup 3}, and J{sub r} {approximately} 60 {times} 10{sup {minus}6} Tkg{sup {minus}1} m{sup 3} in the composition for which x is equal to 0.5 ion/f.u. The magnetic parameters have been measured by the vibration magnetometer.

Gruskova, A. [Slovak Univ. of Technology, Bratislava (Slovakia). Dept. of Electrotechnology] [Slovak Univ. of Technology, Bratislava (Slovakia). Dept. of Electrotechnology

1994-03-01

352

A new polymorph of barium chloroanilate trihydrate.  

PubMed

Single crystals of a new polymorph of the title compound, barium(II) 3,6-dichloro-2,5-dihydroxy-1,4-benzoquinone trihydrate, Ba2+.C6Cl2O4(2-).3H2O, have been grown in sodium metasilicate gel. Each Ba2+ cation is coordinated by eight O atoms. The Ba2+ cations are bridged by an O atom of a ligand around the centre of symmetry at Wyckoff position 4a and by the O atom of a water molecule around the centre of symmetry at Wyckoff position 4b, forming a sheet parallel to the (100) plane. Loose contacts are found around one of the water molecules, as observed in the Cmca form. PMID:11173382

Kashino, S; Ishida, H; Fukunaga, T; Oishi, S

2001-01-01

353

Calculated emission rates for barium releases in space  

NASA Technical Reports Server (NTRS)

The optical emissions from barium releases in space are caused by resonance and fluorescent scattering of sunlight. Emission rates for the dominant ion and neutral lines are calculated assuming the release to be optically thin and the barium to be in radiative equilibrium with the solar radiation. The solar spectrum has deep Fraunhofer absorption lines at the primary barium ion resonances. A velocity component toward or away from the sun will Doppler shift the emission lines relative to the absorption lines and the emission rates will increase many-fold over the rest value. The Doppler brightening is important in shaped charge or satellite releases where the barium is injected at high velocities. Emission rates as a function of velocity are calculated for the 4554, 4934, 5854, 6142 and 6497 A ion emission lines and the dominant neutral line at 5535 A. Results are presented for injection parallel to the ambient magnetic field, B, and for injection at an angle to B.

Stenbaek-Nielsen, H. C.

1989-01-01

354

Synthesis, photoluminescence and magnetic properties of barium vanadate nanoflowers  

SciTech Connect

Graphical abstract: The flower-shaped barium vanadate was obtained for the first time. The photoluminescence and magnetic properties of the barium vanadate nanoflowers were investigated at room temperature. Research highlights: {yields} In the paper, the flower-shaped barium vanadate were obtained for the first time. The CHM method used here is new and simple for preparation of barium vanadate. {yields} The photoluminescence and magnetic properties of the barium vanadate nanoflowers were investigated at room temperature. The strong bluish-green emission was observed. {yields} The ferromagnetic behavior of the barium vanadate nanoflowers was found with saturation magnetization of about 83.50 x 10{sup -3} emu/g, coercivity of 18.89 Oe and remnant magnetization of 4.63 x 10{sup -3} emu/g. {yields} The mechanisms of PL and magnetic property of barium vanadate nanoflowers have been discussed. -- Abstract: The flower-shaped barium vanadate has been obtained by the composite hydroxide mediated (CHM) method from V{sub 2}O{sub 5} and BaCl{sub 2} at 200 {sup o}C for 13 h. XRD and XPS spectrum of the as-synthesized sample indicate it is hexagonal Ba{sub 3}V{sub 2}O{sub 8} with small amount of Ba{sub 3}VO{sub 4.8} coexistence. Scan electron microscope and transmission electron microscope display that the flower-shaped crystals are composed of nanosheets with thickness of {approx}20 nm. The UV-visible spectrum shows that the barium vanadate sample has two optical gaps (3.85 eV and 3.12 eV). Photoluminescence spectrum of the barium vanadate flowers exhibits a visible light emission centered at 492 and 525 nm which might be attributed to VO{sub 4} tetrahedron with T{sub d} symmetry in Ba{sub 3}V{sub 2}O{sub 8}. The ferromagnetic behavior of the barium vanadate nanoflowers has been found with saturation magnetization of about 83.50 x 10{sup -3} emu/g, coercivity of 18.89 Oe and remnant magnetization of 4.63 x 10{sup -3} emu/g, which is mainly due to the presence of a non-orthovanadate phase with spin S = 1/2.

Xu, Jing [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China) [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China); Chongqing University of Science and Technology, Chongqing 401331 (China); Hu, Chenguo, E-mail: hucg@cqu.edu.cn [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China)] [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China); Xi, Yi [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China)] [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China); Peng, Chen [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China)] [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Wan, Buyong; He, Xiaoshan [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China)] [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China)

2011-06-15

355

A search for technetium (Tc II) in barium stars  

NASA Technical Reports Server (NTRS)

The authors searched without success for the lines of Tc II at 2647.02, 2610.00 and 2543.24 A in IUE spectra of the barium stars HR 5058, Omicron Vir, and Zeta Cap. The lack of Tc II implies that the observed s-process enhancements were produced more than half a million years ago and supports the suggestion that the spectral peculiarities of barium stars are probably related to the binary nature of the stars.

Little-Marenin, Irene R.; Little, Stephen J.

1987-01-01

356

'Skidding' of the CRRES G-9 barium release  

NASA Technical Reports Server (NTRS)

A simulation study and experimental data of the CRRES G-9 ionospheric barium release are presented. The simulation study is based on a 2D electrostatic code that incorporates time-dependent coupling to the background plasma. It is shown that the densest portion of the barium ion cloud 'skids' about 15 km within the first three seconds following the release, consistent with the optical data analyses.

Huba, J. D.; Mitchell, H. G.; Fedder, J. A.; Bernhardt, P. A.

1992-01-01

357

Growth and characterization of barium ferrite films grown using PECVD  

Microsoft Academic Search

Deposition of c-axis perpendicularly oriented barium ferrite (BaFe12O19) films was attempted by means of plasma enhanced chemical vapor deposition (PECVD). A substituted acetylacetonate barium complex has been used with ferrocene in a PECVD system to deposit films of BaFe12O19. These films were examined for crystallinity, composition and magnetic properties. The crystallinity was measured by x-ray diffraction (XRD), the composition was

Radhakrishnan Padmanabhan; Ehab Marji; Yanko Kranov; Daqing Zhang; David N. McIlroy

2004-01-01

358

Effect of anions on selective solubilization of zinc and copper in bacterial leaching of sulfide ores.  

PubMed

Bacterial leaching of sulfide ores using Thiobacillus ferrooxidans, Thiobacillus thiooxidans, or a combination of the two was studied at various concentrations of specific anions. Selective zinc and copper solubilization was obtained by inhibiting iron oxidation without affecting sulfur/sulfide oxidation. Phosphate reduced iron solubilization from a pyrite (FeS(2))-sphalerite (ZnS) mixture without significantly affecting zinc solubilization. Copper leaching from a chalcopyrite (CuFeS(2))-sphalerite mixture was stimulated by phosphate, whereas chloride accelerated zinc extraction. In a complex sulfide ore containing pyrite, chalcopyrite, and sphalerite, both phosphate and chloride reduced iron solubilization and increased copper extraction, whereas only chloride stimulated zinc extraction. Maximum leaching obtained was 100% zinc and 50% copper. Time-course studies of copper and zinc solubilization suggest the possibility of selective metal recovery following treatment with specific anions. PMID:10861398

Harahuc, L; Lizama, H M; Suzuki, I

2000-07-20

359

Fatal barium chloride poisoning: four cases report and literature review.  

PubMed

Barium is an alkaline earth metal which has a variety of uses including in the manufacturing industry and in medicine. However, adverse health effects and fatalities occur due to absorption of soluble barium compounds, notably the chloride, nitrate, and hydroxide, which are toxic to humans. Although rare, accidental and suicidal modes of poisoning are sporadically reported in the literature.We describe 4 cases of poisoning due to barium chloride in China. In witnessed cases, severe gastrointestinal symptoms, hypokalemia leading to muscle weakness, cardiac arrhythmias, and respiratory failure were noted. Autopsy showed some nonspecific but common findings, such as subendocardial hemorrhage in the ventricles, visceral petechiae, and fatty changes in the liver. Interestingly, microscopic examination showed degenerative changes and amorphous, flocculent foamy materials in the renal tubules. Toxicology was relevant for barium in blood and tissues. Three of the cases were accidental and 1 homicidal in nature. A round-up of relevant literature on fatal barium compounds poisoning is also provided. Forensic pathologists should be aware of the clinical presentations of barium compound poisoning and especially look for any evidence of hypokalemia. Still, postmortem toxicological and histological studies are essential for an accurate identification of the cause of death. PMID:23629399

Ananda, Sunnassee; Shaohua, Zhu; Liang, Liu

2013-06-01

360

Tetrathiomolybdate Inhibits Copper Trafficking Proteins Through Metal Cluster Formation  

SciTech Connect

Tetrathiomolybdate (TM) is an orally active agent for treatment of disorders of copper metabolism. Here we describe how TM inhibits proteins that regulate copper physiology. Crystallographic results reveal that the surprising stability of the drug complex with the metallochaperone Atx1 arises from formation of a sulfur-bridged copper-molybdenum cluster reminiscent of those found in molybdenum and iron sulfur proteins. Spectroscopic studies indicate that this cluster is stable in solution and corresponds to physiological clusters isolated from TM-treated Wilson's disease animal models. Finally, mechanistic studies show that the drug-metallochaperone inhibits metal transfer functions between copper-trafficking proteins. The results are consistent with a model wherein TM can directly and reversibly down-regulate copper delivery to secreted metalloenzymes and suggest that proteins involved in metal regulation might be fruitful drug targets.

Alvarez, Hamsell M.; Xue, Yi; Robinson, Chandler D.; Canalizo-Hernández, Mónica A.; Marvin, Rebecca G.; Kelly, Rebekah A.; Mondragón, Alfonso; Penner-Hahn, James E.; O’ Halloran, Thomas V. (Michigan); (NWU)

2010-05-06

361

Synthesis of single-crystal barium titanium isopropoxide complex to form barium titanate  

SciTech Connect

Single-crystal barium titanate double alkoxide complex with a composition presumed to be BaTi(OCH(CH[sub 3])[sub 2])[sub 6][center dot]xC[sub 6]H[sub 6] was successfully synthesized in this work. The crystal was converted to BaTiO[sub 3] at 100 C. The preparation of the oxides via single crystals of metal alkoxides has some advantage over the well-known sol-gel method in that it results in oxides with well-defined and homogeneous compositions at the atomic level and in fine particle sizes, smaller than 50 nm.

Suyama, Yoko (Japan Fine Ceramic Center, Nagoya (Japan)); Nagasawa, Mitsuru (Toyota Technological Inst., Nagoya (Japan))

1994-02-01

362

DISSOLVED ORGANIC CARBON CHARACTERISTICS IN METAL-RICH WATERS AND THE IMPLICATIONS FOR COPPER AQUATIC TOXICITY  

EPA Science Inventory

This research will aim to quantify the effects of fractionation between DOC, HFO, HAO, free copper and the behavior of resultant free DOC in the water column on the toxicological effects of copper. Fractionation between DOC, free metals and iron (Fe) and aluminum (Al) hydro...

363

SORPTION OF COPPER IN SOILS AS INFLUENCED BY SOIL PH AND ORGANIC AMENDMENTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Copper (Cu) is generally added to agricultural soils either as an ingredient in fungicides or in soil amendments, i.e. sewage sludge or manures. High Cu levels in soils can antagonize the uptake of other micro-elements, most notably iron, zinc, and molybdenum. Copper content in most soils varies f...

364

High copper concentrations in squid livers in association with elevated levels of silver, cadmium, and zinc  

Microsoft Academic Search

Livers from 43 Loligo opalescens, 14 Ommastrephes bartrami, and 7 Symplectoteuthis oualaniensis were analyzed for their silver, cadmium, copper, zinc and iron contents. Copper concentrations of up to 15,000 µg\\/g dry weight were found in L. opalescens in conjunction with significant correlations between this element and Ag, Cd and Zn. The latter elements are known to affect Cu metabolism in

J. H. Martin; A. R. Flegal

1975-01-01

365

Biokinetics and effects of barium sulfate nanoparticles.  

PubMed

BackgroundNanoparticulate barium sulfate has potential novel applications and wide use in the polymer and paint industries. Only a short-term inhalation study on barium sulfate nanoparticles (BaSO4 NPs) has been published [Part Fibre Toxicol 11:16, 2014]. We performed comprehensive biokinetic studies of 131BaSO4 NPs administered via different routes and of acute and subchronic pulmonary responses to instilled or inhaled BaSO4 in rats.MethodsWe compared the tissue distribution of 131Ba over 28 days after intratracheal (IT) instillation, and over 7 days after gavage and intravenous (IV) injection of 131BaSO4. Rats were exposed to 50 mg/m3 BaSO4 aerosol for 4 or 13 weeks (6 h/day, 5 consecutive days/week), gross and histopathology, blood and bronchoalveolar lavage (BAL) fluid analyses were performed. BAL fluid from instilled rats was also analyzed.ResultsInhaled BaSO4 NPs showed no toxicity after 4-week exposure, but a slight neutrophil increase in BAL after 13-week exposure was observed. Lung burden of inhaled BaSO4 NPs after 4-week exposure (0.84¿±¿0.18 mg/lung) decreased by 95% over 34 days. Instilled BaSO4 NPs caused dose-dependent inflammatory responses in the lungs. Instilled BaSO4 NPs (0.28 mg/lung) was cleared with a half-life of¿¿¿9.6 days. Translocated 131Ba from the lungs was predominantly found in the bone (29%). Only 0.15% of gavaged dose was detected in all organs at 7 days. IV-injected 131BaSO4 NPs were predominantly localized in the liver, spleen, lungs and bone at 2 hours, but redistributed from the liver to bone over time. Fecal excretion was the dominant elimination pathway for all three routes of exposure.ConclusionsPulmonary exposure to instilled BaSO4 NPs caused dose-dependent lung injury and inflammation. Four-week and 13-week inhalation exposures to a high concentration (50 mg/m3) of BaSO4 NPs elicited minimal pulmonary response and no systemic effects. Instilled and inhaled BaSO4 NPs were cleared quickly yet resulted in higher tissue retention than when ingested. Particle dissolution is a likely mechanism. Injected BaSO4 NPs localized in the reticuloendothelial organs and redistributed to the bone over time. BaSO4 NP exhibited lower toxicity and biopersistence in the lungs compared to other poorly soluble NPs such as CeO2 and TiO2. PMID:25331813

Konduru, Nagarjun; Keller, Jana; Ma-Hock, Lan; Gröters, Sibylle; Landsiedel, Robert; Donaghey, Thomas C; Brain, Joseph D; Wohlleben, Wendel; Molina, Ramon M

2014-10-21

366

D-penicillamine treatment of copper-associated hepatitis in Labrador retrievers.  

PubMed

d-penicillamine is effectively used in the lifelong treatment of copper toxicosis in Bedlington terriers and Wilson's disease in humans. A complex form of copper-associated hepatitis has recently been characterized in the Labrador retriever. The aims of this study were to evaluate the effectiveness of d-penicillamine treatment for copper-associated hepatitis in this breed, to study the effects on hepatic copper, iron and zinc concentrations, and to evaluate parameters to predict optimal duration of treatment. Forty-three client owned Labrador retrievers that were diagnosed with increased hepatic copper were treated with d-penicillamine and underwent at least one follow-up examination including a liver biopsy for histopathological scoring of inflammatory lesions. Hepatic copper, iron and zinc concentrations were determined in the initial and follow-up biopsies by instrumental neutron activation analysis. The influence of initial hepatic copper concentration, sex, age, d-penicillamine formulation and the occurrence of side effects were investigated for their influence on hepatic copper concentration after a certain period of treatment by generalized mixed modelling. d-penicillamine proved to be effective in reducing hepatic copper concentration and associated inflammatory lesions. Parameters derived from the model can be used to estimate the necessary duration of d-penicillamine treatment for Labrador retrievers with increased hepatic copper concentration. Continuous, lifelong d-penicillamine treatment is not recommended in this breed, as there may be a risk for hepatic copper and zinc deficiency. PMID:23375251

Fieten, Hille; Dirksen, Karen; van den Ingh, Ted S G A M; Winter, Esther A; Watson, Adrian L; Leegwater, Peter A J; Rothuizen, Jan

2013-06-01

367

Copper sensitivity of cueO mutants of Escherichia coli K-12 and the biochemical suppression of this phenotype.  

PubMed

The cueO gene of Escherichia coli encodes a multi-copper oxidase, which contributes to copper tolerance in this bacterium. It was observed that a cueO mutant was highly sensitive to killing by copper ions when cells were grown on defined minimal media. Copper sensitivity was correlated with accumulation of copper in the mutant strain. Growth of the cueO mutant in the presence of copper could be restored by addition of divalent zinc and manganese ions or ferrous iron but not by other first row transition metal ions or magnesium ions. Copper toxicity towards a cueO mutant could also be suppressed by addition of the superoxide quencher 1,2-dihydroxybenzene-3,5-disulfonic acid (tiron), suggesting that a primary cause of copper toxicity is the copper-catalyzed production of superoxide anions in the cytoplasm. PMID:15708004

Tree, Jai J; Kidd, Stephen P; Jennings, Michael P; McEwan, Alastair G

2005-03-25

368

Prospects for Barium Tagging in Gaseous Xenon  

SciTech Connect

Tagging events with the coincident detection of a barium ion would greatly reduce the background for a neutrino-less double beta decay search in xenon. This paper describes progress towards realizing this goal. It outlines a source that can produce large quantities of Ba++ in gas, shows that this can be extracted to vacuum, and demonstrates a mechanism by which the Ba++ can be efficiently converted to Ba+ as required for laser identification. It is clear from this study that electrospray is a convenient mechanism for producing Ba++ is gas at atmospheric pressure. It is likely that the source will perform just as effectively at higher pressures. Even though the source region has water vapour and methanol vapour at the 0.3% level, there is no evidence for molecular formation. The use of TEA offers an effective method to achieve the charge state conversion. The overall design of the ion extraction from high pressure to vacuum is very similar to the scheme proposed for the final detector and this appears to work well although the efficiency is not yet determined.

Sinclair, D.; /Carleton U. /TRIUMF; Rollin, E.; /Carleton U.; Smith, J.; /Carleton U.; Mommers, A.; /Ottawa U.; Ackerman, N.; /SLAC; Aharmim, B.; /Laurentian U.; Auger, M.; /Bern U., LHEP; Barbeau, P.S.; /Stanford U., Phys. Dept.; Benitez-Medina, C.; /Colorado State U.; Breidenbach, M.; /SLAC; Burenkov, A.; /Moscow, ITEP; Cook, S.; /SLAC; Coppens, A.; /Carleton U.; Daniels, T.; /Massachusetts U., Amherst; DeVoe, R.; /Stanford U., Phys. Dept.; Dobi, A.; /Maryland U.; Dolinski, M.J.; Donato, K.; /Stanford U., Phys. Dept.; Fairbank, W., Jr.; /Colorado State U.; Farine, J.; /Laurentian U.; Giroux, G.; /Bern U., LHEP /Carleton U. /Stanford U., Phys. Dept. /Carleton U. /Laurentian U. /Carleton U. /SLAC /Indiana U. /Indiana U., CEEM /Korea U. /Stanford U., Phys. Dept. /SLAC /Alabama U. /Colorado State U. /Stanford U., Phys. Dept. /Alabama U. /SLAC /Stanford U., Phys. Dept. /Alabama U. /Massachusetts U., Amherst /SLAC /Alabama U. /SLAC /Maryland U. /Moscow, ITEP /Stanford U., Phys. Dept. /Maryland U. /Bern U., LHEP /Laurentian U. /SLAC /Maryland U.

2012-05-03

369

Co-doped Barium Phosphate Glass  

NASA Astrophysics Data System (ADS)

Co-doping of a P2O5:BaO glass matrix with divalent tin and trivalent samarium ions has been realized by the melt-quenching technique with the purpose of investigating the material's luminescent properties. Photoluminescence excitation spectra obtained by monitoring Sm3+ 4G5/2 emission showed a broad excitation band around 290 nm (absent in a Sm3+-doped reference), typical of donor/acceptor energy transfer. Under such excitation, the material exhibits a reddish-white emission. Time-resolved spectra recorded under the 290-nm excitation (non-resonant with Sm3+ excitation peaks) exposed a broad blue-white band characteristic of twofold-coordinated Sn centers and orange-red emission bands of Sm3+ ions, which appeared well separated in time in accord with their emission decay dynamics. Consequently, the data indicate that light absorption occurs at Sn centers (donors) followed by energy transfer to samarium ions (acceptors) which results in populating the 4G5/2 emitting state in Sm3+. Energy transfer pathways likely resulting in the sensitization of Sm3+ photoluminescence are discussed. Results are put into context in terms of the potential of SnO and rare-earth co-doped barium phosphate glasses for use in white light-emitting devices.

Jiménez, J. A.

2014-09-01

370

High H? ionic conductivity in barium hydride  

NASA Astrophysics Data System (ADS)

With hydrogen being seen as a key renewable energy vector, the search for materials exhibiting fast hydrogen transport becomes ever more important. Not only do hydrogen storage materials require high mobility of hydrogen in the solid state, but the efficiency of electrochemical devices is also largely determined by fast ionic transport. Although the heavy alkaline-earth hydrides are of limited interest for their hydrogen storage potential, owing to low gravimetric densities, their ionic nature may prove useful in new electrochemical applications, especially as an ionically conducting electrolyte material. Here we show that barium hydride shows fast pure ionic transport of hydride ions (H?) in the high-temperature, high-symmetry phase. Although some conductivity studies have been reported on related materials previously, the nature of the charge carriers has not been determined. BaH2 gives rise to hydride ion conductivity of 0.2 S cm?1 at 630 °C. This is an order of magnitude larger than that of state-of-the-art proton-conducting perovskites or oxide ion conductors at this temperature. These results suggest that the alkaline-earth hydrides form an important new family of materials, with potential use in a number of applications, such as separation membranes, electrochemical reactors and so on.

Verbraeken, Maarten C.; Cheung, Chaksum; Suard, Emmanuelle; Irvine, John T. S.

2015-01-01

371

High H(-) ionic conductivity in barium hydride.  

PubMed

With hydrogen being seen as a key renewable energy vector, the search for materials exhibiting fast hydrogen transport becomes ever more important. Not only do hydrogen storage materials require high mobility of hydrogen in the solid state, but the efficiency of electrochemical devices is also largely determined by fast ionic transport. Although the heavy alkaline-earth hydrides are of limited interest for their hydrogen storage potential, owing to low gravimetric densities, their ionic nature may prove useful in new electrochemical applications, especially as an ionically conducting electrolyte material. Here we show that barium hydride shows fast pure ionic transport of hydride ions (H(-)) in the high-temperature, high-symmetry phase. Although some conductivity studies have been reported on related materials previously, the nature of the charge carriers has not been determined. BaH2 gives rise to hydride ion conductivity of 0.2 S cm(-1) at 630 °C. This is an order of magnitude larger than that of state-of-the-art proton-conducting perovskites or oxide ion conductors at this temperature. These results suggest that the alkaline-earth hydrides form an important new family of materials, with potential use in a number of applications, such as separation membranes, electrochemical reactors and so on. PMID:25485988

Verbraeken, Maarten C; Cheung, Chaksum; Suard, Emmanuelle; Irvine, John T S

2015-01-01

372

Pyroelectric properties of barium strontium titanate films: Effect of thermal M. W. Cole,2  

E-print Network

Pyroelectric properties of barium strontium titanate films: Effect of thermal stresses J. Zhang,1 M pyroelectric properties of 001 -textured polycrystalline barium strontium titanate BaxSr1-xTiO3, BST films

Alpay, S. Pamir

373

Cooling laser system for quantum computing with barium-137 ions Tom Chartrand  

E-print Network

Cooling laser system for quantum computing with barium-137 ions Tom Chartrand Department of Physics for essentially any application. We have been trapping 137-barium with this end in mind. The odd isotope has

Blinov, Boris

374

Tracking Phaselock Loop Characteristics with a VCO Using a Barium Strontium Titanate (BST)  

E-print Network

Tracking Phaselock Loop Characteristics with a VCO Using a Barium Strontium Titanate (BST) Thin University, Raleigh, NC-27695-7919,USA, Ph: +1-919-767-3277, Email: avictor@harris.com Abstract -- Barium

375

Impact of thermal strain on the dielectric constant of sputtered barium strontium titanate thin films  

E-print Network

Impact of thermal strain on the dielectric constant of sputtered barium strontium titanate thin, California 93106 Received 6 November 2001; accepted for publication 10 January 2002 Barium strontium titanate

York, Robert A.

376

Millimeter wave phase shifter based on ferromagnetic resonance in a hexagonal barium ferrite thin film  

E-print Network

Millimeter wave phase shifter based on ferromagnetic resonance in a hexagonal barium ferrite thin of an M-type barium ferrite BaM thin film prepared by pulsed laser deposition and a coplanar waveguide

377

Über die bei der Uranspaltung auftretenden kurzlebigen Barium und Lanthan-Isotope  

Microsoft Academic Search

Zusammenfassung 1. Das früher für ein primäres Spaltprodukt des Urans gehaltene sog. „14-Minuten-Barium“ wurde auch im „aktiven Niederschlag“ aus hochemanierendem Uran nachgewiesen. Es entsteht also, wie die anderen bisher bekannten Barium-Isotope, ebenfalls aus Xenon.

Otto Hahn; Fritz Strassmann

1942-01-01

378

Demystifying Controlling Copper Corrosion  

EPA Science Inventory

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

379

Copper metabolism of astrocytes  

PubMed Central

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

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

2013-01-01

380

Copper metabolism of astrocytes.  

PubMed

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

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

2013-01-01

381

Acceleration of barium ions near 8000 km above an aurora  

NASA Technical Reports Server (NTRS)

A barium shaped charge, named Limerick, was released from a rocket launched from Poker Flat Research Range, Alaska, on March 30, 1982, at 1033 UT. The release took place in a small auroral breakup. The jet of ionized barium reached an altitude of 8100 km 14.5 min after release, indicating that there were no parallel electric fields below this altitude. At 8100 km the jet appeared to stop. Analysis shows that the barium at this altitude was effectively removed from the tip. It is concluded that the barium was actually accelerated upward, resulting in a large decrease in the line-of-sight density and hence the optical intensity. The parallel electric potential in the acceleration region must have been greater than 1 kV over an altitude interval of less than 200 km. The acceleration region, although presumably auroral in origin, did not seem to be related to individual auroral structures, but appeared to be a large-scale horizontal structure. The perpendicular electric field below, as deduced from the drift of the barium, was temporally and spatially very uniform and showed no variation related to individual auroral structures passing through.

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

1984-01-01

382

Emission spectrographic determination of barium in sea water using a cation exchange concentration procedure  

USGS Publications Warehouse

A concentration technique employing Dowex 50W cation exchange resin is described for the determination of barium in sea water. The separated barium is precipitated as fluoride together with calcium and strontium and measured by emission spectrographic analysis. The vertical distribution of barium in sea water has been measured in the Caribbean Sea and the Atlantic Ocean. The barium content varied between 7 and 23 ??g. per liter; in two profiles, the lowest concentrations were at a depth of about 1000 meters.

Szabo, B. J.; Joensuu, O.

1967-01-01

383

Copper pathways in Plasmodium falciparum infected erythrocytes indicate an efflux role for the copper P-ATPase  

PubMed Central

Copper, like iron, is a transition metal that can generate oxygen radicals by the Fenton reaction. The Plasmodium parasite invades an erythrocyte host cell containing 20 ?M copper, of which 70% is contained in the Cu/Zn SOD (cuprozinc superoxide dismutase). In the present study, we follow the copper pathways in the Plasmodium-infected erythrocyte. Metal-determination analysis shows that the total copper content of Percoll-purified trophozoite-stage-infected erythrocytes is 66% that of uninfected erythrocytes. This decrease parallels the decrease seen in Cu/Zn SOD levels in parasite-infected erythrocytes. Neocuproine, an intracellular copper chelator, arrests parasites at the ring-to-trophozoite stage transition and also specifically decreases intraparasitic levels of Cu/Zn SOD and catalase. Up to 150 ?M BCS (2,9-dimethyl-4,7-diphenyl-1,10-phenanthrolinedisulphonic acid), an extracellular copper chelator, has no effect on parasite growth. We characterized a single copy PfCuP-ATPase (Plasmodium falciparum copper P-ATPase) transporter, which, like the Crypto-sporidium parvum copper P-ATPase, has a single copper-binding domain: ‘Met-Xaa-Cys-Xaa-Xaa-Cys’. Recombinant expression of the N-terminal metal-binding domain reveals that the protein specifically binds reduced copper. Transcription of the PfCuP-ATPase gene is the highest at late ring stage/early trophozoite, and is down-regulated in the presence of neocuproine. Immunofluorescence and electron microscopy indicate the transporter to be both in the parasite and on the erythrocyte membrane. Both the decrease in total copper and the location of the PfCuP-ATPase gene indicate a copper-efflux pathway from the infected erythrocyte. PMID:15125686

2004-01-01

384

Technical development: CT colonography without cathartic cleansing and with barium as the sole tagging agent  

Microsoft Academic Search

The purpose of this study was to perform CT colonography (CTC) without cathartic colon cleansing. Four groups of 3 patients were prepared the day before CTC with a dedicated low residue diet, a hydration control allowing 2 liters of fluid intake and barium as tagging agent. Four different barium regimens were investigated. Groups 1 and 3 ingested barium over 1

Philippe Lefere; Stefaan Gryspeerdt; Marc Baekelandt; Bartel Van Holsbeeck

2004-01-01

385

Dielectric tunability of graded barium strontium titanate multilayers: Effect of thermal strains  

E-print Network

Dielectric tunability of graded barium strontium titanate multilayers: Effect of thermal strains M TEC of a multilayered barium strontium titanate Ba1-ySryTiO3 BST ferroelectric heterostructure such as barium strontium titanate Ba1-ySryTiO3 BST have emerged as leading candidates for such applications due

Alpay, S. Pamir

386

Enhanced Sintering of Yttrium-Doped Barium Zirconate by Addition of ZnO  

E-print Network

Enhanced Sintering of Yttrium-Doped Barium Zirconate by Addition of ZnO Peter Babilo and Sossina M properties of doped barium zirconate have been examined. With the use of zinc ox- ide as a sintering aid, Ba of the material under flowing CO2 showed ZnO-modified barium zirconate to exhibit excellent chemical stability

Haile, Sossina M.

387

Spectroscopy of Ba and Ba+ deposits in solid xenon for barium tagging in  

E-print Network

Spectroscopy of Ba and Ba+ deposits in solid xenon for barium tagging in nEXO B. Mong,1, 2 S. Cook, Vermillion SD, USA (Dated: October 13, 2014) Progress on a method of barium tagging for the nEXO double beta decay experiment is reported. Absorption and emission spectra for deposits of barium atoms and ions

Gratta, Giorgio

388

Synthesis and Structural Diversity of Barium (N,N-Dimethylamino)diboranates  

E-print Network

Synthesis and Structural Diversity of Barium (N,N-Dimethylamino)diboranates Scott R. Daly, Brian J. The reaction of 1 or 1 with Lewis bases that bind more strongly to barium than diethyl ether results that several of the barium complexes are monomeric in the solid state, none is appreciably volatile up to 200

Girolami, Gregory S.

389

Influence of Ba content on grain size and dynamics of crystallization in barium ferrite thin films  

E-print Network

Influence of Ba content on grain size and dynamics of crystallization in barium ferrite thin films of the crystallization process, which ultimately determines the grain size, were studied in barium ferrite thin films. Rapid thermal annealing was used to crystallize the amorphous as-deposited barium ferrite films

Laughlin, David E.

390

A comparison between excess barium and barite as indicators of carbon export  

E-print Network

A comparison between excess barium and barite as indicators of carbon export Meagan Eagle and Adina in many paleoproductivity studies. Barite, the main carrier of particulate barium in the water column in some locations. We demonstrate that Baexcess (total barium minus the fraction associated

Paytan, Adina

391

Barium ferrite thin film media with perpendicular c-axis orientation and small grain size  

E-print Network

Barium ferrite thin film media with perpendicular c-axis orientation and small grain size Zailong, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 Barium ferrite thin films with perpendicular c conditions. The c-axis orientation of barium ferrite thin films is most sensitive to the oxygen partial

Laughlin, David E.

392

49 CFR 173.182 - Barium azide-50 percent or more water wet.  

Code of Federal Regulations, 2011 CFR

... 2011-10-01 2011-10-01 false Barium azide-50 percent or more water wet. 173...Other Than Class 1 and Class 7 § 173.182 Barium azide—50 percent or more water wet. Barium azide—50 percent or more water wet,...

2011-10-01

393

MNRAS 428, 32523261 (2013) doi:10.1093/mnras/sts270 Barium abundances in Cepheids  

E-print Network

MNRAS 428, 3252­3261 (2013) doi:10.1093/mnras/sts270 Barium abundances in Cepheids S. M. Andrievsky; in original form 2012 August 28 ABSTRACT We derived the barium atmospheric abundances for a large sample to 15 kpc, so it is appropriate to investigate the existence of radial barium abundance gradients

Maciel, Walter Junqueira

394

Journal of Crystal Growth 300 (2007) 330335 Growth and optical property characterization of textured barium  

E-print Network

of textured barium titanate thin films for photonic applications Matthew J. DickenÃ?, Kenneth Diest, Young. D.P. Norton Available online 21 December 2006 Abstract We have investigated the growth of barium layers on amorphous and silicon substrates. Growth of highly oriented barium titanate films

Atwater, Harry

395

Discrete Barium Strontium Titanate (BST) Thin-Film Interdigital Varactors on Alumina: Design, Fabrication, Characterization, and  

E-print Network

Discrete Barium Strontium Titanate (BST) Thin-Film Interdigital Varactors on Alumina: Design, Raleigh, NC-27695-7914, USA. Email:jayeshnath@ieee.org Abstract -- Discrete Barium Strontium Titanate (BST, capacitors, BST, ferroelectric, thin-film, barium strontium titanate, bandpass filter, IP3, ACPR, temperature

396

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Barium manganese oxide (BaMnO3). 721.10010...Chemical Substances § 721.10010 Barium manganese oxide (BaMnO3 ). (a...The chemical substance identified as barium manganese oxide (BaMnO3 )...

2013-07-01

397

Effect of Microwave Frequency on Hydrothermal Synthesis of Nanocrystalline Tetragonal Barium Titanate  

E-print Network

Effect of Microwave Frequency on Hydrothermal Synthesis of Nanocrystalline Tetragonal Barium, 2007; ReVised Manuscript ReceiVed: April 29, 2008 Nanocrystalline tetragonal barium titanate (BaTiO3. The dependence of properties of barium titanate on microwave frequency could be due to different transverse

Dutta, Prabir K.

398

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Barium manganese oxide (BaMnO3). 721.10010...Chemical Substances § 721.10010 Barium manganese oxide (BaMnO3 ). (a...The chemical substance identified as barium manganese oxide (BaMnO3 )...

2014-07-01

399

Noncollinear Optical Frequency Doubling in Strontium Barium Niobate Arthur R. Tunyagi, Michael Ulex, and Klaus Betzler*  

E-print Network

Noncollinear Optical Frequency Doubling in Strontium Barium Niobate Arthur R. Tunyagi, Michael Ulex of a novel noncollinear optical second-harmonic generation mechanism is reported. In strontium barium niobate mechanism which we detected in crystals of strontium barium niobate (SBN)--cone-shaped second

Osnabrück, Universität

400

Spectroscopy of Eu3+ ions in congruent strontium barium niobate crystals  

E-print Network

Spectroscopy of Eu3+ ions in congruent strontium barium niobate crystals Ã?. Andresen, A.-N. Bahar properties of single crystals of strontium barium niobate, grown from the congruently melting composition, electro-optic, pho- torefractive, and dielectric properties, the solid solution strontium barium niobate

Osnabrück, Universität

401

Optogalvanic detection of barium high-lying levels with a two-step pulsed laser excitation  

E-print Network

L-513 Optogalvanic detection of barium high-lying levels with a two-step pulsed laser excitation P barium have been investigated by using a two-step pulsed laser excitation combined with an optogalvanic number for the ground state. In barium the ground level has a J = 0 value, so with a two- photon process

Boyer, Edmond

402

75 FR 36629 - Barium Chloride From the People's Republic of China: Continuation of Antidumping Duty Order  

Federal Register 2010, 2011, 2012, 2013, 2014

...Trade Administration [A-570-007] Barium Chloride From the People's Republic...revocation of the antidumping duty order on barium chloride from the People's Republic...review of the antidumping duty order on barium chloride from the PRC pursuant to...

2010-06-28

403

Processing of yttrium-doped barium zirconate for high proton conductivity  

E-print Network

Processing of yttrium-doped barium zirconate for high proton conductivity Peter Babilo Materials the transport properties of yttrium-doped barium zirconate (BYZ) have been explored, with the aim of attaining­100 nm) and high-temperature sintering (1600 °C) in the presence of excess barium were essential

404

M-type barium hexaferrite synthesis and characterization for phase shifter applications  

E-print Network

M-type barium hexaferrite synthesis and characterization for phase shifter applications A. T. Wise; published online 13 April 2011) M-type barium hexaferrite films have been grown by liquid phase epitaxy half a percent. VC 2011 American Institute of Physics. [doi:10.1063/1.3559471] Since M-type barium

McHenry, Michael E.

405

Distribution of barium in the Weddell Gyre: Impact of circulation and biogeochemical processes  

E-print Network

of barium in the Weddell Gyre: Impact of circulation and biogeochemical processes M. Hoppemaa,1 , F@vub.ac.be Key words : Barium; silicate; geochemical cycle; (Southern Ocean, Weddell Sea) Manuscript Click here barium (Bad) has been augmented significantly with two sections across the Weddell Gyre sampled

Paris-Sud XI, Université de

406

Phase associations of barium in marine sediments Meagan Eagle Gonneea *, Adina Paytan 1  

E-print Network

Phase associations of barium in marine sediments Meagan Eagle Gonneea *, Adina Paytan 1 Department 2006 Abstract Barium (Ba) is associated with various phases in marine sediments, including carbonates-export productivity. D 2005 Elsevier B.V. All rights reserved. Keywords: Barium; Barite; Marine sediment; Sedimentary

Paytan, Adina

407

Defect Chemistry of Yttrium-Doped Barium Zirconate: A Thermodynamic Analysis of Water Uptake  

E-print Network

Defect Chemistry of Yttrium-Doped Barium Zirconate: A Thermodynamic Analysis of Water Uptake-based SOFCs.3 Of known proton conducting oxides, yttrium-doped barium zirconate (BYZ) is particularly mobile species. Doping with trivalent yttrium onto the tetravalent zirconium in barium zirconate

408

Barium Titanate Nanoparticles in Block Copolymer Tu Lee,*,, Nan Yao, Hiroaki Imai,, and Ilhan A. Aksay,  

E-print Network

Barium Titanate Nanoparticles in Block Copolymer Tu Lee,*,, Nan Yao, Hiroaki Imai,, and Ilhan A-polybutadiene-polystyrene (Kraton D1102). The barium titanated Kraton thin film had remnants of the cylindrical morphology of a plain Kraton thin film with an interdomain spacing of 23 nm. The procedure of barium titanation

Aksay, Ilhan A.

409

The effect of stress on the dielectric properties of barium strontium titanate thin films  

E-print Network

The effect of stress on the dielectric properties of barium strontium titanate thin films T. M Barium strontium titanate thin films are being developed as capacitors in dynamic random access memories to their large permittivities, barium strontium titan- ate BST bulk ceramics have long been used to make high

Suo, Zhigang

410

Introduction Strontium Barium Niobate k-Space Spectroscopy Results Conclusions Unraveling Relaxor Phase Transitions by  

E-print Network

Introduction Strontium Barium Niobate k-Space Spectroscopy Results Conclusions Unraveling Relaxor 2009 WILLIAMSBURG WORKSHOP ON FUNDAMENTAL PHYSICS OF FERROELECTRICS #12;Introduction Strontium Barium ferroelectrics Introduction Strontium Barium Niobate k-Space Spectroscopy Results Conclusions SBN ­ SrxBa1-xNb2O6

Osnabrück, Universität

411

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Barium manganese oxide (BaMnO3). 721.10010...Chemical Substances § 721.10010 Barium manganese oxide (BaMnO3 ). (a...The chemical substance identified as barium manganese oxide (BaMnO3 )...

2012-07-01

412

Optimization of the tunability of barium strontium titanate films via epitaxial stresses  

E-print Network

Optimization of the tunability of barium strontium titanate films via epitaxial stresses Z.-G. Ban The tunability of epitaxial barium strontium titanate films is analyzed theoretically using a phenomenological.1063/1.1524310 I. INTRODUCTION Thin films of barium strontium titanate (BaxSr1 xTiO3, BST have long been recognized

Alpay, S. Pamir

413

1 Barium and carbon fluxes in the Canadian Arctic Archipelago 2 Helmuth Thomas,1  

E-print Network

1 Barium and carbon fluxes in the Canadian Arctic Archipelago 2 Helmuth Thomas,1 Elizabeth Shadwick Barium (Ba) in the Amundsen Gulf, 8 southeastern Beaufort Sea, was monitored over a full year from observed at river mouths, the lowest concentrations are found in water 12 masses of Atlantic origin. Barium

Boyer, Edmond

414

Structure evolution and dielectric behavior of polystyrene-capped barium titanate nanoparticles  

E-print Network

Structure evolution and dielectric behavior of polystyrene-capped barium titanate nanoparticles H35600g Polystyrene-capped barium titanate (BaTiO3) nanoparticles with sizes of 11 nm and 27 nm were nanocrystals. 1. Introduction Barium titanate (BaTiO3), one of the most commonly used perovskite compounds

Lin, Zhiqun

415

PHYSICAL REVIEW A 88, 023403 (2013) Production of translationally cold barium monohalide ions  

E-print Network

PHYSICAL REVIEW A 88, 023403 (2013) Production of translationally cold barium monohalide ions M. V) We have produced sympathetically cooled barium monohalide ions BaX+ (X = F, Cl, Br) by reacting with these predictions. Producing BaX+ ions in this way is simple and allows for the study of different barium monohalide

Chapman, Michael

416

PHYSICAL REVIEW A 81, 052328 (2010) Hyperfine and optical barium ion qubits  

E-print Network

PHYSICAL REVIEW A 81, 052328 (2010) Hyperfine and optical barium ion qubits M. R. Dietrich,* N these profoundly quantum systems. Despite a long history in ion trapping [3­5], barium has never previously been a natural source without isotope-selective ionization [6,7]. Barium possesses a long-lived metastable state

Blinov, Boris

417

Nanoscale Patterning of Barium Titanate on Block Tu Lee,, Nan Yao, and Ilhan A. Aksay*,,  

E-print Network

Nanoscale Patterning of Barium Titanate on Block Copolymers Tu Lee,, Nan Yao, and Ilhan A. Aksay of polystyrene-polybutadiene-polystyrene (Kraton D1102) has been used to pattern barium titanate precursor on the unsaturated carbon bonds in the polybutadiene matrix with antistereochemistry. Anchoring the barium titanate

Aksay, Ilhan A.

418

Barium Ion Extraction and Identification from Laser Induced Fluorescence in Gas for the  

E-print Network

Barium Ion Extraction and Identification from Laser Induced Fluorescence in Gas for the Enriched the barium ion daughter from the double beta decay of xenon-136 using laser induced fluorescence. The technique is very complex and requires an excellent understanding of the barium ion spectroscopy and its

Wechsler, Risa H.

419

TEE BARIUM CONTENT IN THE CALCAREOUS SKELETAL MATERTALS OF SOME RECENT AND  

E-print Network

TEE BARIUM CONTENT IN THE CALCAREOUS SKELETAL MATERTALS OF SOME RECENT AND FOSSIL CORALS known mlxtures of the 'vrlo m inerals. Ion-exchange methods hrere utllized to separate barium from on ln the Ilvlng eorals varled from 5- 2 + IOS ppn, to L2.5 + 6.1+% ppr. ThtB varJ-atlon ln barium

Luther, Douglas S.

420

Phase diagrams and dielectric response of epitaxial barium strontium titanate films: A theoretical analysis  

E-print Network

Phase diagrams and dielectric response of epitaxial barium strontium titanate films: A theoretical for publication 7 March 2002 We develop phase diagrams for single-domain epitaxial barium strontium titanate films. DOI: 10.1063/1.1473675 I. INTRODUCTION Thin films of barium strontium titanate BaxSr1 xTiO3 ,(BST

Alpay, S. Pamir

421

49 CFR 173.182 - Barium azide-50 percent or more water wet.  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 2010-10-01 false Barium azide-50 percent or more water wet. 173...Other Than Class 1 and Class 7 § 173.182 Barium azide—50 percent or more water wet. Barium azide—50 percent or more water wet,...

2010-10-01

422

Compact high power barium nitrite crystal-based Raman laser at 1197 nm  

E-print Network

Compact high power barium nitrite crystal-based Raman laser at 1197 nm for photoacoustic imaging of fat Rui Li Mikhail N. Slipchenko Pu Wang Ji-Xin Cheng #12;Compact high power barium nitrite crystal such a barrier, we demonstrate the construction and use of a com- pact, barium nitrite crystal-based Raman laser

Cheng, Ji-Xin

423

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Barium manganese oxide (BaMnO3). 721.10010...Chemical Substances § 721.10010 Barium manganese oxide (BaMnO3). (a...The chemical substance identified as barium manganese oxide (BaMnO3 )...

2011-07-01

424

Discrete barite particles and barium as tracers of paleoproductivity in South Atlantic sediments  

Microsoft Academic Search

Geochemical analyses as well as X ray diffraction measurements were carried out on five sediment cores from the eastern Angola Basin and the equatorial divergence of the South Atlantic. Barite concentrations were calculated from total barium concentrations by subtracting the estimated barium background supplied by ``nonbarite'' barium carriers. Barite concentrations assessed by this geochemical method show a good correspondence to

Franz Gingele; Andreas Dahmke

1994-01-01

425

Optimization of High Tunability Barium Strontium Titanate Thin Films Grown by RF Magnetron  

E-print Network

Optimization of High Tunability Barium Strontium Titanate Thin Films Grown by RF Magnetron Abstract-- Barium strontium titanate is a solid solution perovskite with a field-dependent permittivity.7 MV/cm. I. INTRODUCTION In recent years there has been much interest in thin-film barium strontium

York, Robert A.

426

49 CFR 173.182 - Barium azide-50 percent or more water wet.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 2013-10-01 false Barium azide-50 percent or more water wet. 173...Other Than Class 1 and Class 7 § 173.182 Barium azide—50 percent or more water wet. Barium azide—50 percent or more water wet,...

2013-10-01

427

Single-crystal barium titanate thin films by ion slicing T. Izuhara,a)  

E-print Network

Single-crystal barium titanate thin films by ion slicing T. Izuhara,a) I.-L. Gheorma, and R. M, D.C. 20052 Received 19 September 2002; accepted 3 December 2002 Thin barium titanate films, 0.5­8 m.1063/1.1540727 Barium titanate, BaTiO3 BTO , is a ferroelectric crystal whose outstanding electrical and optical

Reeves, Mark E.

428

M-type barium hexaferrite synthesis and characterization for phase shifter applications  

E-print Network

M-type barium hexaferrite synthesis and characterization for phase shifter applications A. T. Wise subject to AIP license or copyright; see http://jap.aip.org/about/rights_and_permissions #12;M-type barium-type barium hexaferrite films have been grown by liquid phase epitaxy and examined by x-ray diffraction

Laughlin, David E.

429

Microwave dielectric properties of graded barium strontium titanate films M. W. Cole,1,a  

E-print Network

Microwave dielectric properties of graded barium strontium titanate films M. W. Cole,1,a C. V Received 8 April 2008; accepted 13 April 2008; published online 8 May 2008 Compositionally graded barium, delay lines, filters, and phase shifters for steerable antennas.1­3 Barium strontium titanate BaxSr1-x

Alpay, S. Pamir

430

Journal of Crystal Growth 271 (2004) 128133 Growth of strontium barium niobate  

E-print Network

Journal of Crystal Growth 271 (2004) 128­133 Growth of strontium barium niobate: the liquidus. Roth Available online 11 September 2004 Abstract The liquidus­solidus phase diagram of strontium barium, and dielectric properties, strontium barium niobate, SrxBa1�xNb2O6--hen- ceforth denoted as SBN, is one

Osnabrück, Universität

431

High tunability barium strontium titanate thin films for rf circuit applications  

E-print Network

High tunability barium strontium titanate thin films for rf circuit applications N. K. Pervez,a) P) Large variations in the permittivity of rf magnetron sputtered thin-film barium strontium titanate have/cm. © 2004 American Institute of Physics. [DOI: 10.1063/1.1818724] Barium strontium titanate (BST) is a solid

York, Robert A.

432

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Barium manganese oxide (BaMnO3). 721.10010...Chemical Substances § 721.10010 Barium manganese oxide (BaMnO3). (a...The chemical substance identified as barium manganese oxide (BaMnO3 )...

2010-07-01

433

49 CFR 173.182 - Barium azide-50 percent or more water wet.  

Code of Federal Regulations, 2014 CFR

... 2014-10-01 2014-10-01 false Barium azide-50 percent or more water wet. 173...Other Than Class 1 and Class 7 § 173.182 Barium azide—50 percent or more water wet. Barium azide—50 percent or more water wet,...

2014-10-01

434

Single-Crystalline Barium Titanate By Jeffrey J. Urban, Jonathan E. Spanier, Lian Ouyang,  

E-print Network

Single-Crystalline Barium Titanate Nanowires By Jeffrey J. Urban, Jonathan E. Spanier, Lian Ouyang composed of barium titanate (BaTiO3), a prototypical displacive ferroelectric material[14,15] that yields-volatile memory devices with an integration density approaching 1 terabit cm±2 . 2. Synthesis of Barium Titanate

Heller, Eric

435

21 CFR 201.304 - Tannic acid and barium enema preparations.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Tannic acid and barium enema preparations. 201...Specific Drug Products § 201.304 Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to...

2013-04-01

436

21 CFR 201.304 - Tannic acid and barium enema preparations.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Tannic acid and barium enema preparations. 201...Specific Drug Products § 201.304 Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to...

2012-04-01

437

21 CFR 201.304 - Tannic acid and barium enema preparations.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Tannic acid and barium enema preparations. 201...Specific Drug Products § 201.304 Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to...

2014-04-01

438

21 CFR 201.304 - Tannic acid and barium enema preparations.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Tannic acid and barium enema preparations. 201...Specific Drug Products § 201.304 Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to...

2010-04-01

439

21 CFR 201.304 - Tannic acid and barium enema preparations.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Tannic acid and barium enema preparations. 201...Specific Drug Products § 201.304 Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to...

2011-04-01

440

Prompt ionization in the CRIT II barium releases  

NASA Astrophysics Data System (ADS)

Observations of electron and ion distributions inside a fast neutral barium jet in the ionosphere show significant fluxes within 4 km of release, presumably related to beam plasma instability processes involved in the Critical Ionization Velocity (CIV) effect. Electron fluxes exceeding 5 x 10 exp 12/sq cm-str-sec-keV were responsible for ionizing both the streaming barium and ambient oxygen. Resulting ion fluxes seem to be consistent with 1-2 percent ionization of the fast barium, as reported by optical observations, although the extended spatial distribution of the optically observed ions is difficult to reconcile with the in situ observations. When the perpendicular velocity of the neutrals falls below critical values, these processes shut off. Although these observations resemble the earlier Porcupine experimental results (Haerendel, 1982), theoretical understanding of the differences between these data and that of earlier negative experiments is still lacking.

Torbert, R. B.; Kletzing, C. A.; Liou, K.; Rau, D.

1992-05-01

441

Barium Levels in Soils and Centella asiatica  

PubMed Central

In this study, Centella asiatica and surface soils were collected from 12 sampling sites in Peninsular Malaysia, and the barium (Ba) concentrations were determined. The Ba concentration [?g/g dry weight (dw)] was 63.72 to 382.01 ?g/g in soils while in C. asiatica, Ba concentrations ranged from 5.05 to 21.88 ?g/g for roots, 3.31 to 11.22 ?g/g for leaves and 2.37 to 6.14 ?g/g for stems. In C. asiatica, Ba accumulation was found to be the highest in roots followed by leaves and stems. The correlation coefficients (r) of Ba between plants and soils were found to be significantly positively correlated, with the highest correlation being between roots-soils (r=0.922, p<005), followed by leaves-soils (r=0.890, p<005) and stems-soils (r=0.848, p<005). This indicates that these three parts of C. asiatica are good biomonitors of Ba pollution. For the transplantation study, four sites were selected as unpolluted [(Universiti Putra Malaysia (UPM)], semi-polluted (Seri Kembangan and Balakong) and polluted sites (Juru). Based on the transplantation study under experimental field and laboratory conditions, Ba concentrations in C. asiatica were significantly (p<0.05) higher after three weeks of exposure at Seri Kembangan, Balakong and Juru. Thus, these experimental findings confirm that the leaves, stems and roots of C. asiatica can reflect the Ba levels in the soils where this plant is found. Three weeks after back transplantation to clean soils, the Ba levels in C. asiatica were still higher than the initial Ba level even though Ba elimination occurred. In conclusion, the leaves, stems and roots of C. asiatica are good biomonitors of Ba pollution. PMID:24575242

Ong, Ghim Hock; Yap, Chee Kong; Mahmood, Maziah; Tan, Soon Guan; Hamzah, Suhaimi

2013-01-01

442

Selectivity in biomineralization of barium and strontium.  

PubMed

The desmid green alga Closterium moniliferum belongs to a small number of organisms that form barite (BaSO(4)) or celestite (SrSO(4)) biominerals. The ability to sequester Sr in the presence of an excess of Ca is of considerable interest for the remediation of (90)Sr from the environment and nuclear waste. While most cells dynamically regulate the concentration of the second messenger Ca(2+) in the cytosol and various organelles, transport proteins rarely discriminate strongly between Ca, Sr, and Ba. Herein, we investigate how these ions are trafficked in C. moniliferum and how precipitation of (Ba,Sr)SO(4) crystals occurs in the terminal vacuoles. Towards this goal, we simultaneously visualize intracellular dynamics of multiple elements using X-ray fluorescence microscopy (XFM) of cryo-fixed/freeze-dried samples. We correlate the resulting elemental maps with ultrastructural information gleaned from freeze-fracture cryo-SEM of frozen-hydrated cells and use micro X-ray absorption near edge structure (micro-XANES) to determine sulfur speciation. We find that the kinetics of Sr uptake and efflux depend on external Ca concentrations, and Sr, Ba, and Ca show similar intracellular localization. A highly ion-selective cross-membrane transport step is not evident. Based on elevated levels of sulfate detected in the terminal vacuoles, we propose a "sulfate trap" model, where the presence of dissolved barium leads to preferential precipitation of (Ba,Sr)SO(4) due to its low solubility relative to SrSO(4) and CaSO(4). Engineering the sulfate concentration in the vacuole may thus be the most direct way to increase the Sr sequestered per cell, an important consideration in using desmids for phytoremediation of (90)Sr. PMID:21871966

Krejci, Minna R; Wasserman, Brian; Finney, Lydia; McNulty, Ian; Legnini, Daniel; Vogt, Stefan; Joester, Derk

2011-11-01

443

Compact pulse forming line using barium titanate ceramic material  

NASA Astrophysics Data System (ADS)

Ceramic material has very high relative permittivity, so compact pulse forming line can be made using these materials. Barium titanate (BaTiO3) has a relative permittivity of 1200 so it is used for making compact pulse forming line (PFL). Barium titanate also has piezoelectric effects so it cracks during high voltages discharges due to stresses developed in it. Barium titanate is mixed with rubber which absorbs the piezoelectric stresses when the PFL is charged and regain its original shape after the discharge. A composite mixture of barium titanate with the neoprene rubber is prepared. The relative permittivity of the composite mixture is measured to be 85. A coaxial pulse forming line of inner diameter 120 mm, outer diameter 240 mm, and length 350 mm is made and the composite mixture of barium titanate and neoprene rubber is filled between the inner and outer cylinders. The PFL is charged up to 120 kV and discharged into 5 ? load. The voltage pulse of 70 kV, 21 ns is measured across the load. The conventional PFL is made up of oil or plastics dielectrics with the relative permittivity of 2-10 [D. R. Linde, CRC Handbook of Chemistry and Physics, 90th ed. (CRC, 2009); Xia et al., Rev. Sci. Instrum. 79, 086113 (2008); Yang et al., Rev. Sci. Instrum. 81, 43303 (2010)], which increases the length of PFL. We have reported the compactness in length achieved due to increase in relative permittivity of composite mixture by adding barium titanate in neoprene rubber.

Kumar Sharma, Surender; Deb, P.; Shukla, R.; Prabaharan, T.; Shyam, A.

2011-11-01

444

Ionization and expansion of barium clouds in the ionosphere  

NASA Technical Reports Server (NTRS)

A recently envelope 3D model is used here to study the motion of the barium clouds released in the ionosphere, including the ionization stage. The ionization and the expansion of the barium clouds and the interaction between the clouds and the background ions are investigated using three simulations: a cloud without a directional velocity, a cloud with an initial velocity of 5 km/s across the B field, and a cloud with initial velocity components of 2 km/s both along and across the B field.

Ma, T.-Z.; Schunk, R. W.

1993-01-01

445

Photoionization and Photoelectric Loading of Barium Ion Traps  

E-print Network

Simple and effective techniques for loading barium ions into linear Paul traps are demonstrated. Two-step photoionization of neutral barium is achieved using a weak intercombination line (6s2 1S0 6s6p 3P1, 791 nm) followed by excitation above the ionization threshold using a nitrogen gas laser (337 nm). Isotopic selectivity is achieved by using a near Doppler-free geometry for excitation of the triplet 6s6p 3P1 state. Additionally, we report a particularly simple and efficient trap loading technique that employs an in-expensive UV epoxy curing lamp to generate photoelectrons.

A. V. Steele; L. R. Churchill; P. F. Griffin; M. S. Chapman

2007-03-22

446

[Mutagen activity of barium chloride in Salmonella typhimurium].  

PubMed

Barium chloride, which is an important industrial chemical used in pigments, lacquers, dyes, glass and pesticide production, leather tanning and cloth dying, was tested on Salmonella typhimurium (TA 1535, TA 1537, TA 1538, TA 97, TA 98, TA 100) with the reverse mutation test, with and without metabolic activation, to assess its possible genotoxic effects and any possible action with respect to standard mutagens (sodium azide, 9-aminoacridine, 2-nitrofluorene, mitomycine-C, 2 aminoacridine). Using the platelet incorporation technique, barium chloride at various progressive concentrations gave negative results under the experimental conditions of the study. PMID:2199807

Monaco, M; Dominici, R; Barisano, P; Di Palermo, G

1990-01-01

447

Methods for producing monodispersed particles of barium titanate  

DOEpatents

The present invention is a low-temperature controlled method for producing high-quality, ultrafine monodispersed nanocrystalline microsphere powders of barium titanate and other pure or composite oxide materials having particles ranging from nanosized to micronsized particles. The method of the subject invention comprises a two-stage process. The first stage produces high quality monodispersed hydrous titania microsphere particles prepared by homogeneous precipitation via dielectric tuning in alcohol-water mixed solutions of inorganic salts. Titanium tetrachloride is used as an inorganic salt precursor material. The second stage converts the pure hydrous titania microsphere particles into crystalline barium titanate microsphere powders via low-temperature, hydrothermal reactions.

Hu, Zhong-Cheng (Knoxville, TN)

2001-01-01

448

Growth and characterization of barium ferrite films grown using PECVD  

NASA Astrophysics Data System (ADS)

Deposition of c-axis perpendicularly oriented barium ferrite (BaFe12O19) films was attempted by means of plasma enhanced chemical vapor deposition (PECVD). A substituted acetylacetonate barium complex has been used with ferrocene in a PECVD system to deposit films of BaFe12O19. These films were examined for crystallinity, composition and magnetic properties. The crystallinity was measured by x-ray diffraction (XRD), the composition was found using scanning electron microscopy (SEM) and energy dispersive analysis of x-rays (EDAX) and the magnetic properties using vibrating sample magnetometry (VSM).

Padmanabhan, Radhakrishnan; Marji, Ehab; Kranov, Yanko; Zhang, Daqing; McIlroy, David N.

2004-05-01

449

COPPER DEFICIENCY PROPHYLAXIS IN GRAZING SHEEP BY COPPER OXIDE INJECTION  

E-print Network

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

Boyer, Edmond