Surface Modification of Zinc with an Oxime for Corrosion Protection in Chloride Medium

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Ganesha Achary

2013-01-01

Full Text Available The surface treatment of zinc was done with different concentrations of an oxime (2E-2-(hydroxylamino-1,2-diphenylethanol molecule by the immersion method. The electrochemical corrosion studies of surface-treated zinc specimens were performed in aqueous sodium chloride solution (1 M, pH 5.0 at different temperatures in order to study the corrosion mechanism. The recorded electrochemical data indicated a basic modification of the cathodic corrosion behavior of the treated zinc resulting in a decrease of the electron transfer rate. The zinc samples treated by immersion in the inhibiting organic solution presented good corrosion resistance. Using scanning electron microscopy (SEM, it was found that a protective film was formed on the surface of zinc.

Anti-inflammatory, antinociceptive and ulcerogenic activity of a zinc-diclofenac complex in rats

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L.H. Santos

2004-08-01

Full Text Available We investigated the anti-inflammatory, antinociceptive and ulcerogenic activity of a zinc-diclofenac complex (5.5 or 11 mg/kg in male Wistar rats (180-300 g, N = 6 and compared it to free diclofenac (5 or 10 mg/kg and to the combination of diclofenac (5 or 10 mg/kg and zinc acetate (1.68 or 3.5 mg/kg. The carrageenin-induced paw edema and the cotton pellet-induced granulomatous tissue formation models were used to assess the anti-inflammatory activity, and the Hargreaves model of thermal hyperalgesia was used to assess the antinociceptive activity. To investigate the effect of orally or intraperitoneally (ip administered drugs on cold-induced gastric lesions, single doses were administered before exposing the animals to a freezer (-18ºC for 45 min in individual cages. We also evaluated the gastric lesions induced by multiple doses of the drugs. Diclofenac plus zinc complex had the same anti-inflammatory and antinociceptive effects as diclofenac alone. Gastric lesions induced by a single dose administered per os and ip were reduced in the group treated with zinc-diclofenac when compared to the groups treated with free diclofenac or diclofenac plus zinc acetate. In the multiple dose treatment, the complex induced a lower number of the most severe lesions when compared to free diclofenac and diclofenac plus zinc acetate. In conclusion, the present study demonstrates that the zinc-diclofenac complex may represent an important therapeutic alternative for the treatment of rheumatic and inflammatory conditions, as its use may be associated with a reduced incidence of gastric lesions.

Chronic zinc exposure decreases the surface expression of NR2A-containing NMDA receptors in cultured hippocampal neurons.

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Jia Zhu

Full Text Available Zinc distributes widely in the central nervous system, especially in the hippocampus, amygdala and cortex. The dynamic balance of zinc is critical for neuronal functions. Zinc modulates the activity of N-methyl-D-aspartate receptors (NMDARs through the direct inhibition and various intracellular signaling pathways. Abnormal NMDAR activities have been implicated in the aetiology of many brain diseases. Sustained zinc accumulation in the extracellular fluid is known to link to pathological conditions. However, the mechanism linking this chronic zinc exposure and NMDAR dysfunction is poorly understood.We reported that chronic zinc exposure reduced the numbers of NR1 and NR2A clusters in cultured hippocampal pyramidal neurons. Whole-cell and synaptic NR2A-mediated currents also decreased. By contrast, zinc did not affect NR2B, suggesting that chronic zinc exposure specifically influences NR2A-containg NMDARs. Surface biotinylation indicated that zinc exposure attenuated the membrane expression of NR1 and NR2A, which might arise from to the dissociation of the NR2A-PSD-95-Src complex.Chronic zinc exposure perturbs the interaction of NR2A to PSD-95 and causes the disorder of NMDARs in hippocampal neurons, suggesting a novel action of zinc distinct from its acute effects on NMDAR activity.

1 SUPPLEMENTARY INFORMATION A novel zinc(II) complex ...

Indian Academy of Sciences (India)

BİLGİSAYAR

1. SUPPLEMENTARY INFORMATION. A novel zinc(II) complex containing square pyramidal, octahedral and tetrahedral geometries on the same polymeric chain constructed from pyrazine-2,3-dicarboxylic acid and 1-vinylimidazole. HAKAN YILMAZ* and OMER ANDAC. Department of Chemistry, Ondokuz Mayis University, ...

Fabrication of superhydrophobic surface on zinc substrate by 3-trifluoromethylbenzene diazonium tetrafluoroborate salts

International Nuclear Information System (INIS)

Li, Hong; Huang, Chengya; Zhang, Long; Lou, Wanqiu

2014-01-01

Graphical abstract: - Highlights: • Fabrication of stable superhydrophobic Zn surfaces by a reaction with 3-trifluoromethylbenzene diazonium tetrafluoroborate salts. • The highest water contact angle was 160°, and a low sliding angle of about 1°. • The superhydrophobicity was related with the special hierarchical porous microstructure and the low surface energy. • This procedure is facile and effective. - Abstract: In this study we report a new and efficient method of fabricating superhydrophobic surface on zinc plate modified with 3-trifluoromethylbenzene diazonium tetrafluoroborate salts (CF 3 BD), which shows a water contact angle of 160° for a 4 μl water droplet and a low sliding angle of about 1°. The morphology and chemical composition of as-prepared superhydrophobic zinc surfaces are investigated by means of scanning electron microscopy (SEM), electron probe microanalyzer (EPMA) and FT-IR spectrum. The results show that the organic layers formed on zinc plate surface are provided with the special hierarchical porous microstructure and the low surface energy, which lead to the superhydrophobicity surface on the modified zinc

Fabrication of superhydrophobic surface on zinc substrate by 3-trifluoromethylbenzene diazonium tetrafluoroborate salts

Energy Technology Data Exchange (ETDEWEB)

Li, Hong, E-mail: lihong@gdut.edu.cn [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510090 (China); Huang, Chengya; Zhang, Long; Lou, Wanqiu [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China)

2014-09-30

Graphical abstract: - Highlights: • Fabrication of stable superhydrophobic Zn surfaces by a reaction with 3-trifluoromethylbenzene diazonium tetrafluoroborate salts. • The highest water contact angle was 160°, and a low sliding angle of about 1°. • The superhydrophobicity was related with the special hierarchical porous microstructure and the low surface energy. • This procedure is facile and effective. - Abstract: In this study we report a new and efficient method of fabricating superhydrophobic surface on zinc plate modified with 3-trifluoromethylbenzene diazonium tetrafluoroborate salts (CF{sub 3}BD), which shows a water contact angle of 160° for a 4 μl water droplet and a low sliding angle of about 1°. The morphology and chemical composition of as-prepared superhydrophobic zinc surfaces are investigated by means of scanning electron microscopy (SEM), electron probe microanalyzer (EPMA) and FT-IR spectrum. The results show that the organic layers formed on zinc plate surface are provided with the special hierarchical porous microstructure and the low surface energy, which lead to the superhydrophobicity surface on the modified zinc.

Zinc (hydr)oxide/graphite oxide/AuNPs composites: role of surface features in H₂S reactive adsorption.

Science.gov (United States)

Giannakoudakis, Dimitrios A; Bandosz, Teresa J

2014-12-15

Zinc hydroxide/graphite oxide/AuNPs composites with various levels of complexity were synthesized using an in situ precipitation method. Then they were used as H2S adsorbents in visible light. The materials' surfaces were characterized before and after H2S adsorption by various physical and chemical methods (XRD, FTIR, thermal analysis, potentiometric titration, adsorption of nitrogen and SEM/EDX). Significant differences in surface features and synergistic effects were found depending on the materials' composition. Addition of graphite oxide and the deposition of gold nanoparticles resulted in a marked increase in the adsorption capacity in comparison with that on the zinc hydroxide and zinc hydroxide/AuNP. Addition of AuNPs to zinc hydroxide led to a crystalline ZnO/AuNP composite while the zinc hydroxide/graphite oxide/AuNP composite was amorphous. The ZnOH/GO/AuNPs composite exhibited the greatest H2S adsorption capacity due to the increased number of OH terminal groups and the conductive properties of GO that facilitated the electron transfer and consequently the formation of superoxide ions promoting oxidation of hydrogen sulfide. AuNPs present in the composite increased the conductivity, helped with electron transfer to oxygen, and prevented the fast recombination of the electrons and holes. Copyright © 2014 Elsevier Inc. All rights reserved.

A zinc complex of heparan sulfate destabilises lysozyme and alters its conformation

International Nuclear Information System (INIS)

Hughes, Ashley J.; Hussain, Rohanah; Cosentino, Cesare; Guerrini, Marco; Siligardi, Giuliano; Yates, Edwin A.; Rudd, Timothy R.

2012-01-01

Highlights: ► Zinc–heparan sulfate complex destabilises lysozyme, a model amyloid protein. ► Addition of zinc, without heparan sulfate, stabilises lysozyme. ► Heparan sulfate cation complexes provide alternative protein folding routes. -- Abstract: The naturally occurring anionic cell surface polysaccharide heparan sulfate is involved in key biological activities and is implicated in amyloid formation. Following addition of Zn–heparan sulfate, hen lysozyme, a model amyloid forming protein, resembled β-rich amyloid by far UV circular dichroism (increased β-sheet: +25%), with a significantly reduced melting temperature (from 68 to 58 °C) by fluorescence shift assay. Secondary structure stability of the Zn–heparan sulfate complex with lysozyme was also distinct from that with heparan sulfate, under stronger denaturation conditions using synchrotron radiation circular dichroism. Changing the cation associated with heparan sulfate is sufficient to alter the conformation and stability of complexes formed between heparan sulfate and lysozyme, substantially reducing the stability of the protein. Complexes of heparan sulfate and cations, such as Zn, which are abundant in the brain, may provide alternative folding routes for proteins.

Effects of zinc complexes on the distribution of zinc in calcareous soil and zinc uptake by maize.

Science.gov (United States)

Alvarez, José M; Rico, María I

2003-09-10

The movement and availability of Zn from six organic Zn sources in a Typic Xerorthent (calcareous) soil were compared by incubation, column assay, and in a greenhouse study with maize (Zea mays L.). Zinc soil behavior was studied by sequential, diethylenetriaminepentaacetate, and Mehlich-3 extractions. In the incubation experiment, the differences in Zn concentration observed in the water soluble plus exchangeable fraction strongly correlated with Zn uptake by plants in the greenhouse experiment. Zinc applied to the surface of soil columns scarcely moved into deeper layers except for Zn-ethylenediaminetetraacetate (EDTA) that showed the greatest distribution of labile Zn throughout the soil and the highest proportion of leaching of the applied Zn. In the upper part of the column, changes in the chemical forms of all treatments occurred and an increase in organically complexed and amorphous Fe oxide-bound fractions was detected. However, the water soluble plus exchangeable fraction was not detected. The same results were obtained at the end of the greenhouse experiment. Significant increases were found in plant dry matter yield and Zn concentration as compared with the control treatment without Zn addition. Increasing Zn rate in the soil increased dry matter yield in all cases but Zn concentration in the plant increased only with Zn-EDTA and Zn-ethylenediaminedi-o-hydroxyphenyl-acetate (EDDHA) fertilizers. Higher Zn concentration in plants (50.9 mg kg(-)(1)) occurred when 20 mg Zn kg(-)(1) was added to the soil as Zn-EDTA. The relative effectiveness of the different Zn carriers in increasing Zn uptake was in the order: Zn-EDTA > Zn-EDDHA > Zn-heptagluconate >/= Zn-phenolate approximately Zn-polyflavonoid approximately Zn-lignosulfonate.

Structural and antimicrobial properties of irradiated chitosan and its complexes with zinc

International Nuclear Information System (INIS)

Khan, Azam; Mehmood, Shaukat; Shafiq, Muhammad; Yasin, Tariq; Akhter, Zareen; Ahmad, Shabir

2013-01-01

The aim of this research was to evaluate the structural and antimicrobial properties of irradiated chitosan and its complexes with zinc. Chitosan having a molecular weight (M η ) of 220 kDa was exposed to gamma rays in dry, wet and solution forms. The chitosan-zinc complexes were prepared by varying the M η of chitosan and Zn content. Viscometeric analysis revealed a sharp decrease in the M η of chitosan irradiated in solution form even at lower doses compared with the dry and wet forms. X-ray diffraction patterns demonstrated variation in the crystallinity of chitosan upon exposure to gamma rays. The antibacterial response of the irradiated chitosan and its complexes against gram-positive and gram-negative bacteria demonstrated wide spectrum of effective antimicrobial activities, which increased with the dose. Additionally, the complexes exhibited excellent antifungal activity with no growth of Aspergallious fumigatus and Fusarium solani even after two weeks. These results suggested that the irradiated chitosan and its complexes with Zn can be used as antimicrobial additives for various applications. - Highlights: • Gamma radiation is used to lower the molecular weight of chitosan. • The effect of environment on radiation degradation of chitosan is studied. • Its complexes with different amount of zinc are prepared and characterized. • Radiation-degraded chitosan and complexes showed good antibacterial properties

Reactivity of Zinc Halide Complexes Containing Camphor-Derived Guanidine Ligands with Technical rac-Lactide

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Angela Metz

2017-11-01

Full Text Available Three new zinc complexes with monoamine–guanidine hybridligands have been prepared, characterized by X-ray crystallography and NMR spectroscopy, and tested in the solvent-free ring-opening polymerization of rac-lactide. Initially the ligands were synthesized from camphoric acid to obtain TMGca and DMEGca and then reacted with zinc(II halides to form zinc complexes. All complexes have a distorted tetrahedral coordination. They were utilized as catalysts in the solvent-free polymerization of technical rac-lactide at 150 °C. Colorless polylactide (PLA can be produced and after 2 h conversion up to 60% was reached. Furthermore, one zinc chlorido complex was tested with different qualities of lactide (technical and recrystallized and with/without the addition of benzyl alcohol as a co-initiator. The kinetics were monitored by in situ FT-IR or 1H NMR spectroscopy. All kinetic measurements show first-order behavior with respect to lactide. The influence of the chiral complexes on the stereocontrol of PLA was examined. Moreover, with MALDI-ToF measurements the end-group of the obtained polymer was determined. DFT and NBO calculations give further insight into the coordination properties. All in all, these systems are robust against impurities and water in the lactide monomer and show great catalytic activity in the ROP of lactide.

One-step controllable fabrication of superhydrophobic surfaces with special composite structure on zinc substrates.

Science.gov (United States)

Ning, Tao; Xu, Wenguo; Lu, Shixiang

2011-09-01

Stable superhydrophobic platinum surfaces have been effectively fabricated on the zinc substrates through one-step replacement deposition process without further modification or any other post-treatment procedures. The fabrication process was controllable, which could be testified by various morphologies and hydrophobic properties of different prepared samples. By conducting SEM and water CA analysis, the effects of reaction conditions on the surface morphology and hydrophobicity of the resulting surfaces were carefully studied. The results show that the optimum condition of superhydrophobic surface fabrication depends largely on the positioning of zinc plate and the concentrations of reactants. When the zinc plate was placed vertically and the concentration of PtCl(4) solution was 5 mmol/L, the zinc substrate would be covered by a novel and interesting composite structure. The structure was composed by microscale hexagonal cavities, densely packed nanoparticles layer and top micro- and nanoscale flower-like structures, which exhibit great surface roughness and porosity contributing to the superhydrophobicity. The maximal CA value of about 171° was obtained under the same reaction condition. The XRD, XPS and EDX results indicate that crystallite pure platinum nanoparticles were aggregated on the zinc substrates in accordance with a free deposition way. Copyright © 2011 Elsevier Inc. All rights reserved.

Fabrication of an Organic Light-Emitting Diode from New Host π Electron Rich Zinc Complex

Science.gov (United States)

Jafari, Mohammad Reza; Janghouri, Mohammad; Shahedi, Zahra

2017-01-01

A new π electron rich zinc complex was used as a fluorescent material in organic light-emitting diodes (OLEDs). Devices with a structure of indium tin oxide/poly (3,4-ethylenedi-oxythiophene):poly(styrenesulfonate) (PEDOT: PSS) (50 nm)/polyvinylcarbazole (60 nm)/Zn: %2 porphyrin derivatives (45 nm)/Al (150 nm) were fabricated. Porphyrin derivatives accounting for 2 wt.% in the π electron rich zinc complex were used as a host. The electroluminescence (EL) spectra of porphyrin derivatives indicated a red shift, as π electron rich zinc complex EL spectra. The device (4) has also a luminance of 3420 cd/m2 and maximum efficiency of 1.58 cd/A at 15 V, which are the highest values among four devices. The result of Commission International del'Eclairage (CIE) (X, Y) coordinate and EL spectrum of device (3) indicated that it is more red shifted compared to other devices. Results of this work indicate that π electron rich zinc complex is a promising host material for high efficiency red OLEDs and has a simple structure compared to Alq3-based devices.

Surface and capillary forces encountered by zinc sulfide microspheres in aqueous electrolyte.

Science.gov (United States)

Gillies, Graeme; Kappl, Michael; Butt, Hans-Jürgen

2005-06-21

The colloid probe technique was used to investigate the interactions between individual zinc sulfide (ZnS) microspheres and an air bubble in electrolyte solution. Incorporation of zinc ions into the electrolyte solution overcomes the disproportionate zinc ion dissolution and mimics high-volume-fraction conditions common in flotation. Determined interaction forces revealed a distinct lack of long-ranged hydrophobic forces, indicated by the presence of a DLVO repulsion prior to particle engulfment. Single microsphere contact angles were determined from particle-bubble interactions. Contact angles increased with decreasing radii and with surface oxidation. Surface modification by the absorption of copper and subsequently potassium O-ethyldithiocarbonate (KED) reduced repulsive forces and strongly increased contact angles.

Studies on the Interaction between Zinc-Hydroxybenzoite Complex and Genomic DNA

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Hacali Necefoglu

2006-04-01

Full Text Available Zinc-Hydroxybenzoite ([Zn (H206] (p-HO-C6H4COO22H20 complex which wassynthesized and characterized by instrumental methods and the DNA samples which hadbeen isolated from cattle were allowed to interact at 37 oC for different time periods. Theinteraction of genomic DNA with this complex has been followed by agarose gelelectrophoresis at 50 V for 2 h. When DNA samples were allowed to interact with this metalcomplex, it was found that band intensities changed with the concentrations of the complex.In the result of interaction between this complex and genomic DNA samples, it wasdetermined that the intensities of bands were changed at the different concentrations of thecomplex. The brightness of the bands was increased and mobility of the bands wasdecreased, indicating the occurrence of increased covalent binding of the metal complexwith DNA. In this study it was concluded that the damage effect of ascorbate was reducedby Zinc-Hydroxybenzoite.

Dye-Sensitized Solar Cells Based on High Surface Area Nanocrystalline Zinc Oxide Spheres

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Pavuluri Srinivasu

2011-01-01

Full Text Available High surface area nanocrystalline zinc oxide material is fabricated using mesoporous nanostructured carbon as a sacrificial template through combustion process. The resulting material is characterized by XRD, N2 adsorption, HR-SEM, and HR-TEM. The nitrogen adsorption measurement indicates that the materials possess BET specific surface area ca. 30 m2/g. Electron microscopy images prove that the zinc oxide spheres possess particle size in the range of 0.12 μm–0.17 μm. The nanocrystalline zinc oxide spheres show 1.0% of energy conversion efficiency for dye-sensitized solar cells.

Zinc isotope investigation of surface and pore waters in a mountain watershed impacted by acid rock drainage

International Nuclear Information System (INIS)

Aranda, Suzan; Borrok, David M.; Wanty, Richard B.; Balistrieri, Laurie S.

2012-01-01

The pollution of natural waters with metals derived from the oxidation of sulfide minerals like pyrite is a global environmental problem. However, the metal loading pathways and transport mechanisms associated with acid rock drainage reactions are often difficult to characterize using bulk chemical data alone. In this study, we evaluated the use of zinc (Zn) isotopes to complement traditional geochemical tools in the investigation of contaminated waters at the former Waldorf mining site in the Rocky Mountains, Colorado, U.S.A. Geochemical signatures and statistical analysis helped in identifying two primary metal loading pathways at the Waldorf site. The first was characterized by a circumneutral pH, high alkalinity, and high Zn/Cd ratios. The second was characterized by acidic pHs and low Zn/Cd ratios. Zinc isotope signatures in surface water samples collected across the site were remarkably similar (the δ 66 Zn, relative to JMC 3-0749-L, for most samples ranged from 0.20 to 0.30‰ ± 0.09‰ 2σ). This probably suggests that the ultimate source of Zn is consistent across the Waldorf site, regardless of the metal loading pathway. The δ 66 Zn of pore water samples collected within a nearby metal-impacted wetland area, however, were more variable, ranging from 0.20 to 0.80‰ ± 0.09‰ 2σ. Here the Zn isotopes seemed to reflect differences in groundwater flow pathways. However, a host of secondary processes might also have impacted Zn isotopes, including adsorption of Zn onto soil components, complexation of Zn with dissolved organic matter, uptake of Zn into plants, and the precipitation of Zn during the formation of reduced sulfur species. Zinc isotope analysis proved useful in this study; however, the utility of this isotopic tool would improve considerably with the addition of a comprehensive experimental foundation for interpreting the complex isotopic relationships found in soil pore waters. - Highlights: ► Zinc isotopes of water were measured in

Studying the state of the surface and internal mass of powder-like zinc and cadmium sulfides

International Nuclear Information System (INIS)

Bundel', A.A.; Khozhainov, Yu.M.

1979-01-01

The investigation on the chemical and the phase composition of the surface and the bulk of powder zinc and cadmium sulphides as a function of the conditions of ignition and physico-chemical processing carried out using electron diffraction, X-ray phase and chemical analyses. The electron diffraction analysis has shown that ignition gives rise to zinc oxide on the surface of zinc sulphide particles and in the case of cadmium sulphide, to metallic cadmium. To obtain a pure zinc sulphide, free from its oxide both on the surface and in bulk, use should be made of a deoxidized preparation and all contact with oxidizing medium in subsequent ignition should be eliminated

Synthesis, characterization and thermal behavior of antibacterial and antifungal active zinc complexes of bis (3(4-dimethylaminophenyl)-allylidene-1,2-diaminoethane

International Nuclear Information System (INIS)

Montazerozohori, Morteza; Zahedi, Saeedeh; Naghiha, Asghar; Zohour, Mostafa Montazer

2014-01-01

In this work, synthesis of a new series of zinc halide/pseudohalide complexes of a bidentate Schiff base ligand entitled as bis (3-(4-dimethylaminophenyl)-allylidene)-1,2-diaminoethane(L) is described. The ligand and its zinc complexes were characterized by various techniques such as elemental analysis, FT-IR, UV–visible, 1 H and 13 C NMR spectra, cyclic voltammetry, and conductometry. Accordingly ZnLX 2 (X = Cl − , Br − , I − , SCN − and N 3 − ) was suggested as molecular formula of the complexes. Redox behaviors of ligand and its zinc complexes were investigated by cyclic voltammetry method. Furthermore, the ligand and its zinc halide/pseudohalide complexes were tested for their in vitro antibacterial activities against two gram positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Also in vitro antifungal activities of them against Candida albicans and Aspergillus niger were investigated. The results indicated that all compounds are antibacterial and antifungal active. Thermal behaviors of ligand and its zinc complexes were studied from room temperature to 1100 °C under argon atmosphere. It was found that the ligand and zinc iodide are decomposed completely via three and four steps respectively while other zinc complexes leave out the metal or organometallic compounds as final residuals after 3–4 decomposition steps at above temperature range. Moreover evaluation of some thermo-kinetic parameters such as activation energy (∆E ⁎ ), enthalpy (∆H ⁎ ), entropy (∆S ⁎ ) and Gibbs free energy change (∆G ⁎ ) of the thermal decomposition steps were performed based on the Coats–Redfern relation. - Highlights: • Some novel complexes of Zn(II) with a bidentate Schiff base ligand have been synthesized. • Redox behavior of ligand and zinc complexes was investigated by cyclic voltammetry. • The ligand and its zinc complexes are antibacterial and

An investigation of the electrochemical action of the epoxy zinc-rich coatings containing surface modified aluminum nanoparticle

Energy Technology Data Exchange (ETDEWEB)

Jalili, M. [Nanomaterials and Nanocoatings Department, Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of); Surface Coatings and Corrosion Department, Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of); Rostami, M. [Nanomaterials and Nanocoatings Department, Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of); Ramezanzadeh, B., E-mail: ramezanzadeh-bh@icrc.ac.ir [Surface Coatings and Corrosion Department, Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of)

2015-02-15

Highlights: • Aluminum nanoparticle was modified with amino trimethylene phosphonic acid. • 2 wt% of zinc dust in zinc-rich paint was substituted by aluminum nanoparticles. • Surface modified aluminum nanoparticle improved the cathodic period of protection. • Aluminum nanoparticles enhanced the corrosion protection of the zinc-rich coating. - Abstract: Aluminum nanoparticle was modified with amino trimethylene phosphonic acid (ATMP). The surface characterization of the nanoparticles was done by X-ray photo electron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis. The influence of the replacement of 2 wt% of zinc dust in the standard zinc-rich epoxy coating by nanoparticles on the electrochemical action of the coating was studied by electrochemical impedance spectroscopy (EIS) and salt spray tests. The morphology and phase composition of the zinc rich paints were evaluated by X-ray diffraction (XRD) and filed-emission scanning electron microscopy (FE-SEM). Results showed that the ATMP molecules successfully adsorbed on the surface of Al nanoparticles. Results obtained from salt spray and electrochemical measurements revealed that the addition of surface modified nanoparticles to the zinc rich coating enhanced its galvanic action and corrosion protection properties.

An investigation of the electrochemical action of the epoxy zinc-rich coatings containing surface modified aluminum nanoparticle

International Nuclear Information System (INIS)

Jalili, M.; Rostami, M.; Ramezanzadeh, B.

2015-01-01

Highlights: • Aluminum nanoparticle was modified with amino trimethylene phosphonic acid. • 2 wt% of zinc dust in zinc-rich paint was substituted by aluminum nanoparticles. • Surface modified aluminum nanoparticle improved the cathodic period of protection. • Aluminum nanoparticles enhanced the corrosion protection of the zinc-rich coating. - Abstract: Aluminum nanoparticle was modified with amino trimethylene phosphonic acid (ATMP). The surface characterization of the nanoparticles was done by X-ray photo electron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis. The influence of the replacement of 2 wt% of zinc dust in the standard zinc-rich epoxy coating by nanoparticles on the electrochemical action of the coating was studied by electrochemical impedance spectroscopy (EIS) and salt spray tests. The morphology and phase composition of the zinc rich paints were evaluated by X-ray diffraction (XRD) and filed-emission scanning electron microscopy (FE-SEM). Results showed that the ATMP molecules successfully adsorbed on the surface of Al nanoparticles. Results obtained from salt spray and electrochemical measurements revealed that the addition of surface modified nanoparticles to the zinc rich coating enhanced its galvanic action and corrosion protection properties

Zinc complexed chitosan/TPP nanoparticles: A promising micronutrient nanocarrier suited for foliar application.

Science.gov (United States)

Deshpande, Paresh; Dapkekar, Ashwin; Oak, Manoj D; Paknikar, Kishore M; Rajwade, Jyutika M

2017-06-01

Cultivation of cereals in zinc deficient soils leads to declined nutritional quality of grain. Zinc deficiency in humans is a consequence of consumption of micronutrient deficient cereals as staple food. To achieve an increase in zinc density in grain, we evaluated zinc complexed chitosan nanoparticles (Zn-CNP) as a potential 'nanocarrier' suited for foliar fertilization. Zn-CNP were synthesized using tri-polyphosphate as a cross-linker. Spherical Zn-CNP (diameter 250-300nm) were positively charged (zeta potential, +42.34mV) and contained ∼20mg Zn/g (w/w). Plant growth in zinc deficient sand media, followed by foliar application of Zn-CNP (twice-a-week, for 5 weeks) after anthesis resulted in 27 and 42% increase in grain zinc content of MACS 3125 and UC1114 (durum wheat cultivars) respectively. Translocation of zinc ions from foliar applied Zn-CNP into the leaf and seed tissue was demonstrated using zinquin and dithizone stains, respectively. The study indicates the suitability of chitosan-based nanocarriers in agronomic biofortification. Copyright © 2017 Elsevier Ltd. All rights reserved.

Induced superhydrophobic and antimicrobial character of zinc metal modified ceramic wall tile surfaces

Science.gov (United States)

Özcan, Selçuk; Açıkbaş, Gökhan; Çalış Açıkbaş, Nurcan

2018-04-01

Hydrophobic surfaces are also known to have antimicrobial effect by restricting the adherence of microorganisms. However, ceramic products are produced by high temperature processes resulting in a hydrophilic surface. In this study, an industrial ceramic wall tile glaze composition was modified by the inclusion of metallic zinc powder in the glaze suspension applied on the pre-sintered wall tile bodies by spraying. The glazed tiles were gloss fired at industrially applicable peak temperatures ranging from 980 °C to 1100 °C. The fired tile surfaces were coated with a commercial fluoropolymer avoiding water absorption. The surfaces were characterized with SEM, EDS, XRD techniques, roughness, sessile water drop contact angle, surface energy measurements, and standard antimicrobial tests. The surface hydrophobicity and the antimicrobial activity results were compared with that of unmodified, uncoated gloss fired wall tiles. A superhydrophobic contact angle of 150° was achieved at 1000 °C peak temperature due to the formation of micro-structured nanocrystalline zinc oxide granules providing a specific surface topography. At higher peak temperatures the hydrophobicity was lost as the specific granular surface topography deteriorated with the conversion of zinc oxide granules to the ubiquitous willemite crystals embedded in the glassy matrix. The antimicrobial efficacy also correlated with the hydrophobic character.

Speciation of Zinc Mixed Ligand Complexes in Salt Water Systems ...

African Journals Online (AJOL)

Speciation of Zinc Mixed Ligand Complexes in Salt Water Systems. ... method has been used to study heavy metal interaction in model lake water in KNO3 ... is of no consequential effect because in its normal state, the [OH-] of the lake water is ...

Detecting Latent Prints on Stone and Other Difficult Porous Surfaces via Indanedione/Zinc Chloride and Laser

Directory of Open Access Journals (Sweden)

Shiquan LIU

2016-01-01

Full Text Available Lasers and alternate light sources have been recognized as effective tools for latent print detection for over three decades. Luminescence often increases friction ridge contrast to reveal impressions otherwise undetectable. Indanedione/zinc chloride excited by a forensic light source is widely recognized as an effective process for developing latent prints on porous surfaces. This study was designed to evaluate the use of a combination of luminescence excitation and indanedione with zinc chloride to detect latent prints on stones, bricks, and similar difficult porous surfaces. The wavelengths evaluated included 400 nm (violet, 447 nm (blue, 532 nm (green, and 645 nm (red. Latent prints were deposited on a variety of porous surfaces including bricks, cement stones, wood, and cotton fabric, all commonly encountered at crime scenes in China. The surfaces were examined using white light (light-emitting diode flashlight and laser light sources separately, both before and after treatment with indanedione/zinc chloride. The goal of this study was to evaluate various light sources for their effectiveness in detecting impressions developed by indanedione/zinc chloride on difficult porous surfaces. Results indicated that latent prints on some brick and cement stone surfaces may be effectively detected using 532 nm laser excitation after indanedione/zinc chloride processing.

Controllable wettability and morphology of electrodeposited surfaces on zinc substrates

Energy Technology Data Exchange (ETDEWEB)

Zhang, Binyan; Lu, Shixiang, E-mail: shixianglu@bit.edu.cn; Xu, Wenguo, E-mail: wenguoxu60@bit.edu.cn; Cheng, Yuanyuan

2016-01-01

Graphical abstract: Superhydrophobic surfaces combining hierarchical micro/nanostructures were fabricated on zinc substrates by etching, electrodeposition of ZnO coatings and annealing. Such superhydrophobic surfaces offer possibilities for chemical, biological, electronic and microfluidic applications. - Highlights: • Superhydrophobic surface was fabricated via electrodeposition of ZnO and annealing. • The ZnO hierarchical micro/nanostructures contribute to the surface superhydrophobicity. • Surface wettability and morphology can be controlled by varying process conditions. • The anti-icing properties and reversible wetting behaviors of the ZnO coatings were studied. - Abstract: Superhydrophobic surfaces combining hierarchical micro/nanostructures were fabricated on zinc substrates by etching in hydrochloric acid solution, electrodeposition of ZnO coatings and subsequent thermal annealing. The optimal coatings were electrodeposited at −1.25 V for 900 s on the etched zinc substrates and then annealed at 200 °C for 60 min, which could achieve a maximum water contact angle of 170 ± 2° and an ultra-low sliding angle of approximately 0°. By conducting SEM and water CA analysis, we found that the morphology and wettability of prepared samples were controllable by the fabrication process. Interestingly, even without any additional modification, the samples prepared under different electrodeposition conditions (including Zn(CH{sub 3}COO){sub 2} concentration from 5 mM to 40 mM and deposition time from 300 s to 1500 s) exhibited superhydrophobic character. The influences of the Zn(CH{sub 3}COO){sub 2} concentration, deposition time, annealing temperature and annealing time on the wetting behaviors were also discussed in detail. Such superhydrophobic surfaces possess long-term stability, and good corrosion resistance as well as self-cleaning ability. In addition, the anti-icing properties of the ZnO films were investigated. These surfaces could be rapidly and

Controllable wettability and morphology of electrodeposited surfaces on zinc substrates

International Nuclear Information System (INIS)

Zhang, Binyan; Lu, Shixiang; Xu, Wenguo; Cheng, Yuanyuan

2016-01-01

Graphical abstract: Superhydrophobic surfaces combining hierarchical micro/nanostructures were fabricated on zinc substrates by etching, electrodeposition of ZnO coatings and annealing. Such superhydrophobic surfaces offer possibilities for chemical, biological, electronic and microfluidic applications. - Highlights: • Superhydrophobic surface was fabricated via electrodeposition of ZnO and annealing. • The ZnO hierarchical micro/nanostructures contribute to the surface superhydrophobicity. • Surface wettability and morphology can be controlled by varying process conditions. • The anti-icing properties and reversible wetting behaviors of the ZnO coatings were studied. - Abstract: Superhydrophobic surfaces combining hierarchical micro/nanostructures were fabricated on zinc substrates by etching in hydrochloric acid solution, electrodeposition of ZnO coatings and subsequent thermal annealing. The optimal coatings were electrodeposited at −1.25 V for 900 s on the etched zinc substrates and then annealed at 200 °C for 60 min, which could achieve a maximum water contact angle of 170 ± 2° and an ultra-low sliding angle of approximately 0°. By conducting SEM and water CA analysis, we found that the morphology and wettability of prepared samples were controllable by the fabrication process. Interestingly, even without any additional modification, the samples prepared under different electrodeposition conditions (including Zn(CH_3COO)_2 concentration from 5 mM to 40 mM and deposition time from 300 s to 1500 s) exhibited superhydrophobic character. The influences of the Zn(CH_3COO)_2 concentration, deposition time, annealing temperature and annealing time on the wetting behaviors were also discussed in detail. Such superhydrophobic surfaces possess long-term stability, and good corrosion resistance as well as self-cleaning ability. In addition, the anti-icing properties of the ZnO films were investigated. These surfaces could be rapidly and reversibly switched

The shaping of zinc coating on surface steels and ductile iron casting

Directory of Open Access Journals (Sweden)

D. Kopyciński

2010-01-01

Full Text Available The studies aimed at an analysis of the formation and growth kinetics of zinc coating on reactive silicon-killed steels in a zinc bath. The growth kinetics of the produced zinc coatings was evaluated basing on the power-law growth equation. As regards galvanizing of the surface of products, investigation was done for various steel grades and ductile iron (DI taking into account the quality and thickness of coating. It has been proved that the chemical constitution of basis significantly influences the kinetics of growth of the individual phases in a zinc coating. This relationship was evaluated basing on the, so called, silicon and phosphorus equivalent ESi,P and coating thickness dependences were obtained.

Zinc isotope investigation of surface and pore waters in a mountain watershed impacted by acid rock drainage

Energy Technology Data Exchange (ETDEWEB)

Aranda, Suzan [Department of Geological Sciences, University of Texas at El Paso, El Paso, TX 79968 (United States); Borrok, David M., E-mail: dborrok@utep.edu [Department of Geological Sciences, University of Texas at El Paso, El Paso, TX 79968 (United States); Wanty, Richard B. [US Geological Survey, MS 964d, Denver Federal Center, Denver, CO 80225 (United States); Balistrieri, Laurie S. [U.S. Geological Survey, University of Washington, School of Oceanography, Seattle, WA 98195 (United States)

2012-03-15

The pollution of natural waters with metals derived from the oxidation of sulfide minerals like pyrite is a global environmental problem. However, the metal loading pathways and transport mechanisms associated with acid rock drainage reactions are often difficult to characterize using bulk chemical data alone. In this study, we evaluated the use of zinc (Zn) isotopes to complement traditional geochemical tools in the investigation of contaminated waters at the former Waldorf mining site in the Rocky Mountains, Colorado, U.S.A. Geochemical signatures and statistical analysis helped in identifying two primary metal loading pathways at the Waldorf site. The first was characterized by a circumneutral pH, high alkalinity, and high Zn/Cd ratios. The second was characterized by acidic pHs and low Zn/Cd ratios. Zinc isotope signatures in surface water samples collected across the site were remarkably similar (the {delta}{sup 66}Zn, relative to JMC 3-0749-L, for most samples ranged from 0.20 to 0.30 Per-Mille-Sign {+-} 0.09 Per-Mille-Sign 2{sigma}). This probably suggests that the ultimate source of Zn is consistent across the Waldorf site, regardless of the metal loading pathway. The {delta}{sup 66}Zn of pore water samples collected within a nearby metal-impacted wetland area, however, were more variable, ranging from 0.20 to 0.80 Per-Mille-Sign {+-} 0.09 Per-Mille-Sign 2{sigma}. Here the Zn isotopes seemed to reflect differences in groundwater flow pathways. However, a host of secondary processes might also have impacted Zn isotopes, including adsorption of Zn onto soil components, complexation of Zn with dissolved organic matter, uptake of Zn into plants, and the precipitation of Zn during the formation of reduced sulfur species. Zinc isotope analysis proved useful in this study; however, the utility of this isotopic tool would improve considerably with the addition of a comprehensive experimental foundation for interpreting the complex isotopic relationships found in

Synthesis, characterization and thermal behavior of antibacterial and antifungal active zinc complexes of bis (3(4-dimethylaminophenyl)-allylidene-1,2-diaminoethane

Energy Technology Data Exchange (ETDEWEB)

Montazerozohori, Morteza, E-mail: mmzohori@mail.yu.ac.ir [Department of Chemistry, Yasouj University, Yasouj 75918-74831 (Iran, Islamic Republic of); Zahedi, Saeedeh [Department of Chemistry, Yasouj University, Yasouj 75918-74831 (Iran, Islamic Republic of); Naghiha, Asghar [Department of Animal Sciences, Faculty of Agriculture, Yasouj University, Yasouj (Iran, Islamic Republic of); Zohour, Mostafa Montazer [Genetics of Non-Communicable Disease Research Center, Zahedan University of Medical Sciences, Zahedan (Iran, Islamic Republic of)

2014-02-01

In this work, synthesis of a new series of zinc halide/pseudohalide complexes of a bidentate Schiff base ligand entitled as bis (3-(4-dimethylaminophenyl)-allylidene)-1,2-diaminoethane(L) is described. The ligand and its zinc complexes were characterized by various techniques such as elemental analysis, FT-IR, UV–visible, {sup 1}H and {sup 13}C NMR spectra, cyclic voltammetry, and conductometry. Accordingly ZnLX{sub 2} (X = Cl{sup −}, Br{sup −}, I{sup −}, SCN{sup −} and N{sub 3}{sup −}) was suggested as molecular formula of the complexes. Redox behaviors of ligand and its zinc complexes were investigated by cyclic voltammetry method. Furthermore, the ligand and its zinc halide/pseudohalide complexes were tested for their in vitro antibacterial activities against two gram positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Also in vitro antifungal activities of them against Candida albicans and Aspergillus niger were investigated. The results indicated that all compounds are antibacterial and antifungal active. Thermal behaviors of ligand and its zinc complexes were studied from room temperature to 1100 °C under argon atmosphere. It was found that the ligand and zinc iodide are decomposed completely via three and four steps respectively while other zinc complexes leave out the metal or organometallic compounds as final residuals after 3–4 decomposition steps at above temperature range. Moreover evaluation of some thermo-kinetic parameters such as activation energy (∆E{sup ⁎}), enthalpy (∆H{sup ⁎}), entropy (∆S{sup ⁎}) and Gibbs free energy change (∆G{sup ⁎}) of the thermal decomposition steps were performed based on the Coats–Redfern relation. - Highlights: • Some novel complexes of Zn(II) with a bidentate Schiff base ligand have been synthesized. • Redox behavior of ligand and zinc complexes was investigated by cyclic voltammetry. • The

Surface stoichiometry of zinc sulfide and its effect on the adsorption behaviors of xanthate

Directory of Open Access Journals (Sweden)

Wang Meng

2011-11-01

Full Text Available Abstract In this paper, the surface stoichiometry, acid-base properties as well as the adsorption of xanthate at ZnS surfaces were studied by means of potentiometric titration, adsorption and solution speciation modeling. The surface proton binding site was determined by using Gran plot to evaluate the potentiometric titration data. Testing results implied that for stoichiometric surfaces of zinc sulfide, the proton and hydroxide determine the surface charge. For the nonstoichiometric surfaces, the surface charge is controlled by proton, hydroxide, zinc and sulfide ions depending on specific conditions. The xanthate adsorption decreases with increasing solution pH, which indicates an ion exchange reaction at the surfaces. Based on experimental results, the surface protonation, deprotonation, stoichiometry and xanthate adsorption mechanism were discussed.

Electroluminescence and photosensitivity spectra of organic diode structures based on zinc complexes

Science.gov (United States)

Kaplunov, M. G.; Krasnikova, S. S.; Nikitenko, S. L.; Yakushchenko, I. K.

2017-01-01

Devices based on zinc complexes with sulphanylaminosubstituted ligands are characterized by dual function - electroluminescence (EL) and photosensitivity. Both EL and photosensitivity are associated with the formation of exciplexes.

Isotope aided micronutrient studies in rice production with special reference to zinc deficiency pt.2

International Nuclear Information System (INIS)

Kim, T.S.; Kim, J.S.; Kim, J.S.

1979-01-01

A field experiment has been carried out to evaluate the residual effect of zinc fertilizers by rice plant grown under flooded conditions in the field. The results obtained are summarized as follows: Residual effect of zinc fertilizers on yields of rough and hulled grains showed slight increases. Effect of zinc application methods on yields of the grains were shown that zinc mixed treatment could be more effectively utilized than treatment of zinc on the soil surface. In case of levels of zinc application, 5kg zinc per hectare represented high yields of the grains than those obtained from 10 kg and 20 kg zinc placement per hectare respectively. Regarding the form of zinc fertilizers, the urea-zinc complex showed less effective on yields of the grains than did the zinc sulfate. This phenomenon was consistent with the previous result. Yields of total zinc in rice plant grown on the rice straw added soils (Treatment No. 2 and 8) and the urea-zinc complex treated soil were increased markedly as compared to those data obtained from the previous year. The percentage of zinc derived from fertilizer decreased largely as compared to that of the first year crop. The yield of fertilizer zinc in rice plant decreased slightly in the most zinc treatments but in the case of treatments of zinc mixed with the straw added soil and the urea-zinc complex increased reversely as compared to the previous results. The mixed application of zinc with soil showed higher yield of fertilizer zinc than the soil surface placement. Approximately from 4.6 to 24.3 per cent of zinc taken up by rice plants were derived from the fertilizer zinc. Zinc fertilizer use efficiency ranged from 0.213 to 0.584 per cent when 5 kg zinc per hectare applied. (author)

Electroluminescence and photosensitivity spectra of organic diode structures based on zinc complexes

International Nuclear Information System (INIS)

Kaplunov, M.G.; Krasnikova, S.S.; Nikitenko, S.L.; Yakushchenko, I.K.

2017-01-01

Devices based on zinc complexes with sulphanylaminosubstituted ligands are characterized by dual function – electroluminescence (EL) and photosensitivity. Both EL and photosensitivity are associated with the formation of exciplexes.

Synthesis and characterization of an effective organic/inorganic hybrid green corrosion inhibitive complex based on zinc acetate/Urtica Dioica

International Nuclear Information System (INIS)

Salehi, E.; Naderi, Reza; Ramezanzadeh, B.

2017-01-01

Highlights: • An organic/inorganic hybrid green corrosion inhibitive pigment was synthesized and characterized. • Chemical structure and morphology of the hybrid complex were characterized. • Zinc acetate/Urtica Dioica showed effective inhibition action in saline solution on carbon steel. • The synergistic effect between Zn 2+ cations and inhibitive compounds existed in U.D resulted in protective film deposition on the steel surface. - Abstract: This study aims at synthesis and characterization of an effective corrosion inhibitive complex based on zinc acetate/Urtica Dioica (ZnA-U.D) for corrosion protection of mild steel in chloride solution. The chemical structure and morphology of the complex were characterized by Fourier transform infrared spectroscopy (FT-IR), UV–vis, thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The corrosion protection performance of the mild steel samples dipped in 3.5 wt.% NaCl solutions with and without ZnA-U.D extract was investigated by visual observations, open circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS) and polarization test. Results revealed that the ZnA successfully chelated with organic inhibitive compounds (i.e Quercetin, Quinic acid, Caffeic acid, Hystamine and Serotonin) present in the U.D extract. The electrochemical measurements revealed the effective inhibition action of ZnA-U.D complex in the sodium chloride solution on the mild steel. The synergistic effect between Zn 2+ and organic compounds present in the U.D extract resulted in protective film deposition on the steel surface, which was proved by SEM and XPS analyses.

Synthesis and characterization of an effective organic/inorganic hybrid green corrosion inhibitive complex based on zinc acetate/Urtica Dioica

Energy Technology Data Exchange (ETDEWEB)

Salehi, E.; Naderi, Reza [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Ramezanzadeh, B., E-mail: ramezanzadeh@aut.ac.ir [Department of Surface Coatings and Corrosion, Institute for Color Science and Technology (ICST), PO 16765-654, Tehran (Iran, Islamic Republic of)

2017-02-28

Highlights: • An organic/inorganic hybrid green corrosion inhibitive pigment was synthesized and characterized. • Chemical structure and morphology of the hybrid complex were characterized. • Zinc acetate/Urtica Dioica showed effective inhibition action in saline solution on carbon steel. • The synergistic effect between Zn{sup 2+} cations and inhibitive compounds existed in U.D resulted in protective film deposition on the steel surface. - Abstract: This study aims at synthesis and characterization of an effective corrosion inhibitive complex based on zinc acetate/Urtica Dioica (ZnA-U.D) for corrosion protection of mild steel in chloride solution. The chemical structure and morphology of the complex were characterized by Fourier transform infrared spectroscopy (FT-IR), UV–vis, thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The corrosion protection performance of the mild steel samples dipped in 3.5 wt.% NaCl solutions with and without ZnA-U.D extract was investigated by visual observations, open circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS) and polarization test. Results revealed that the ZnA successfully chelated with organic inhibitive compounds (i.e Quercetin, Quinic acid, Caffeic acid, Hystamine and Serotonin) present in the U.D extract. The electrochemical measurements revealed the effective inhibition action of ZnA-U.D complex in the sodium chloride solution on the mild steel. The synergistic effect between Zn{sup 2+} and organic compounds present in the U.D extract resulted in protective film deposition on the steel surface, which was proved by SEM and XPS analyses.

A Nonbactericidal Zinc-Complexing Ligand as a Biofilm Inhibitor: Structure-Guided Contrasting Effects on Staphylococcus aureus Biofilm.

Science.gov (United States)

Kapoor, Vidushi; Rai, Rajanikant; Thiyagarajan, Durairaj; Mukherjee, Sandipan; Das, Gopal; Ramesh, Aiyagari

2017-08-04

Zinc-complexing ligands are prospective anti-biofilm agents because of the pivotal role of zinc in the formation of Staphylococcus aureus biofilm. Accordingly, the potential of a thiosemicarbazone (compound C1) and a benzothiazole-based ligand (compound C4) in the prevention of S. aureus biofilm formation was assessed. Compound C1 displayed a bimodal activity, hindering biofilm formation only at low concentrations and promoting biofilm growth at higher concentrations. In the case of C4, a dose-dependent inhibition of S. aureus biofilm growth was observed. Atomic force microscopy analysis suggested that at higher concentrations C1 formed globular aggregates, which perhaps formed a substratum that favored adhesion of cells and biofilm formation. In the case of C4, zinc supplementation experiments validated zinc complexation as a plausible mechanism of inhibition of S. aureus biofilm. Interestingly, C4 was nontoxic to cultured HeLa cells and thus has promise as a therapeutic anti-biofilm agent. The essential understanding of the structure-driven implications of zinc-complexing ligands acquired in this study might assist future screening regimes for identification of potent anti-biofilm agents. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chirality sensing with stereodynamic biphenolate zinc complexes.

Science.gov (United States)

Bentley, Keith W; de Los Santos, Zeus A; Weiss, Mary J; Wolf, Christian

2015-10-01

Two bidentate ligands consisting of a fluxional polyarylacetylene framework with terminal phenol groups were synthesized. Reaction with diethylzinc gives stereodynamic complexes that undergo distinct asymmetric transformation of the first kind upon binding of chiral amines and amino alcohols. The substrate-to-ligand chirality imprinting at the zinc coordination sphere results in characteristic circular dichroism signals that can be used for direct enantiomeric excess (ee) analysis. This chemosensing approach bears potential for high-throughput ee screening with small sample amounts and reduced solvent waste compared to traditional high-performance liquid chromatography methods. © 2015 Wiley Periodicals, Inc.

An investigation of the electrochemical action of the epoxy zinc-rich coatings containing surface modified aluminum nanoparticle

Science.gov (United States)

Jalili, M.; Rostami, M.; Ramezanzadeh, B.

2015-02-01

Aluminum nanoparticle was modified with amino trimethylene phosphonic acid (ATMP). The surface characterization of the nanoparticles was done by X-ray photo electron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis. The influence of the replacement of 2 wt% of zinc dust in the standard zinc-rich epoxy coating by nanoparticles on the electrochemical action of the coating was studied by electrochemical impedance spectroscopy (EIS) and salt spray tests. The morphology and phase composition of the zinc rich paints were evaluated by X-ray diffraction (XRD) and filed-emission scanning electron microscopy (FE-SEM). Results showed that the ATMP molecules successfully adsorbed on the surface of Al nanoparticles. Results obtained from salt spray and electrochemical measurements revealed that the addition of surface modified nanoparticles to the zinc rich coating enhanced its galvanic action and corrosion protection properties.

ynthesis, theoretical study on Zinc (II and Ni(II complexes of 5-methoxyisatin 3-[N-(4-chlorophenyl thiosemicarbazone

Directory of Open Access Journals (Sweden)

Fatma Kandemirli

2012-03-01

Full Text Available Zinc(II and nickel(II-complexes of 5-methoxyisatin 3-[N-(4-chlorophenyl thiosemicarbazone] (H2MICP were synthesized and characterized by infrared, ultraviolet and 1H-NMR spectroscopies as well as elemental analysis. Model of H2MICP and its zinc(II and nickel(II-complexes were optimized with B3LYP method using 6-31G(d,p, 6-311G(d,p, 6-311++G(d,p, 6-311++G(2d,2p basis sets. The calculated 1H-NMR, UV and IR spectra data were compared with experimental results. In addition to the Natural Bond Orbital (NBO analysis of H2MICP and its Zinc(II and Nickel(II complexes, Fukui functions of H2MICP were also reported.

THE STUDY OF MOLTEN ZINC INTERACTION ON THE SURFACE OF REFRACTORIES IN THE PRODUCTION OF ZINC OXIDE

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Natália Luptáková

2013-04-01

Full Text Available This paper is closely connected with the complete process of indirect production of ZnO as well as with the problems which occur during the metallurgical process. Purity of raw materials has an important influence on the final quality of ZnO and the occurrence of slag that remains stuck on the walls of furnace linings. ZnO is generally produced in the melting furnaces with different types of ceramic linings. Input materials have to be analyzed and investigated in the order to the predict behavior from the aspect of the complex production process. Moreover, analysis of occurrence of undesirable phases in the batch, the output materials, character of furnace linings and waste material have to be evaluated and observed. Mutual interaction of all components will have a significant impact on the final quality of the ZnO. The result of the investigation of interaction occurring in the components will be used for the proposal of the suitable surface for furnace lining while the mentioned result is mainly obtained on the principle of chemical reactions and bonds. This surface for lining should have a minimum adhesion of the zinc and its alloys relating to production of ZnO.

The study of molten zinc interaction on the surface of refractories in the production of zinc oxide

Directory of Open Access Journals (Sweden)

Natália Luptáková

2013-02-01

Full Text Available This paper is closely connected with the complete process of indirect production of ZnO as well as with the problems which occur during the metallurgical process. Purity of raw materials has an important influence on the final quality of ZnO and the occurrence of slag that remains stuck on the walls of furnace linings. ZnO is generally produced in the melting furnaces with different types of ceramic linings. Input materials have to be analyzed and investigated in the order to the predict behaviour from the aspect of the complex production process. Moreover, analysis of occurrence of undesirable phases in the batch, the output materials, character of furnace linings and waste material have to be evaluated and observed. Mutual interaction of all components will have a significant impact on the final quality of the ZnO. The result of the investigation of interaction occurring in the components will be used for the proposal of the suitable surface for furnace lining while the mentioned result is mainly obtained on the principle of chemical reactions and bonds. This surface for lining should have a minimum adhesion of the zinc and its alloys relating to production of ZnO.

Synthesis, structure and luminescence properties of zinc (II) complexes with terpyridine derivatives as ligands

International Nuclear Information System (INIS)

Chen Xuegang; Zhou Quanguo; Cheng Yanxiang; Geng Yanhou; Ma Dongge; Xie Zhiyuan; Wang Lixiang

2007-01-01

Five zinc (II) complexes (1-5) with 4'-phenyl-2,2':6',2''-terpyridine (ptpy) derivatives as ligands have been synthesized and fully characterized. The para-position of phenyl in ptpy is substituted by the group (R), i.e. tert-butyl (t-Bu), hexyloxy (OHex), carbazole-9-yl (Cz), naphthalen-1-yl-phenyl-amine-N-yl (NPA) and diphenyl amine-N-yl (DPA), with different electron-donating ability. With increasing donor ability of the R, the emission color of the complexes in film was modulated from violet (392 nm) to reddish orange (604 nm). The photoexcited luminescence exhibits significant solvatochromism because the emission of the complexes involves the intra-ligand charge transfer (ILCT) excited state. The electrochemical investigations show that the complexes with stronger electro-donating substituent have lower oxidation potential and then higher HOMO level. The electroluminescence (EL) properties of these zinc (II) complexes were studied with the device structure of ITO/PEDOT/Zn (II) complex: PBD:PMMA/BCP/AlQ/LiF/Al. Complexes 3, 4 and 5 exhibit EL wavelength at 552, 600 and 609 nm with maximum current efficiency of 5.28, 2.83 and 2.00 cd/A, respectively

False-positive result when a diphenylcarbazide spot test is used on trivalent chromium-passivated zinc surfaces

DEFF Research Database (Denmark)

Reveko, Valeriia; Lampert, Felix; Din, Rameez Ud

2018-01-01

chromium passivation on zinc; however, subsequent analysis by XPS could not confirm the presence of chromium in a hexavalent state. Conclusions Unintended oxidation of DPC induced by atmospheric corrosion is suggested as a possible reason for the false-positive reaction of the DPC test on a trivalent......A colorimetric 1,5-diphenylcarbazide (DPC)-based spot test can be used to identify hexavalent chromium on various metallic and leather surfaces. DPC testing on trivalent chromium-passivated zinc surfaces has unexpectedly given positive results in some cases, apparently indicating the presence...... of hexavalent chromium; however, the presence of hexavalent chromium has never been confirmed with more sensitive and accurate test methods. Objectives To examine the presence of hexavalent chromium on trivalent chromium-passivated zinc surfaces with a DPC-based spot test. Methods A colorimetric DPC spot test...

Synthesis, photoluminescence and forensic applications of blue light emitting azomethine-zinc (II complexes of bis(salicylidenecyclohexyl-1,2-diamino based organic ligands

Directory of Open Access Journals (Sweden)

M. Srinivas

2017-06-01

Full Text Available Various azomethine-zinc(II complexes (3a-c of bis(salicylidenecyclohexyl-1,2-diamino organic ligands were synthesized by one pot reaction of salicylaldehydes/2-hydroxy-1-naphthaldehyde (2 eq, cyclohexyl-1,2-diamine (1 eq and zinc acetate (1 eq in methanol solvent at reflux temperature. The synthesized complexes were characterized by FTIR, 1H NMR, and SEM. Their photophysical properties such as Photoluminescence (PL and Diffused Reflectance Spectra (DRS were studied. PL studies revealed that the emission peaks of the complexes in both solution and solid states appeared to occur at 395–600 nm and emitted blue light. The band gap energies determined from DRS were 2.98 eV (3a, 2.91 eV (3b, and 2.73 eV (3c. Based on these results, we ascertain that these Zn(II complexes can serve as a suitable non-dopant blue light emitting compound for flat panel display applications. Latent fingerprint detection study indicated that the powder compounds show good adhesion and finger ridge details without background staining. The demonstrated method can be applied to detect fingerprints on all types of smooth surfaces.

First-principles study on half-metallic zinc-blende CrS and its (001) surface

Energy Technology Data Exchange (ETDEWEB)

Xu, Bin, E-mail: hnsqxb@163.com [Department of Mathematics and Information Sciences, North China university of Water Resources and Electric Power, Zhengzhou 450011 (China); Chen, Leiming [Zhengzhou Institute of Aeronautical Industry Management, Zhengzhou, 450015 (China)

2016-11-01

Half-metallic magnets with complete (100%) spin polarization have attracted growing interest due to the potential in spintronic applications. In this paper, we use the first-principles calculations to explain the seeming contradiction between the recent experimental ferromagnetism (Demper et al., 2012 [22]) and the previous theoretical antiferromagnetic ground state for half-metallic zinc-blende CrS, and the experimental ferromagnetism of zinc-blende CrS arises from the substrate effect. We also show that both Cr- and S-terminated (001) surfaces of CrS preserve the bulk half-metallicity. The calculated surface energy indicates that the S-terminated (001) surface is more stable than the Cr-terminated (001) surface within the whole effective Cr chemical potentials, and thus the S-terminated (001) surface is more likely than the Cr-terminated (001) surface when the CrS thin films are grown on ZnSe substrate.

Zinc removal from wastewater by complexation-microfiltration process

OpenAIRE

Trivunac Katarina; Sekulić Zoran; Stevanović Slavica

2012-01-01

As a result of its wide industrial applications, zinc has become an important contaminant in aquatic environment since it is a toxic heavy metal and some of its compounds such as zinc arsenate and zinc cyanide, may be extremely hazardous. Therefore, there is a growing need for developing simple methods capable of separating and recovering trace zinc from environmental waters. Nowadays, the ultra and microfiltration method for trace metals removal from waters by the addition of water-sol...

Improved colorimetric determination of serum zinc.

Science.gov (United States)

Johnson, D J; Djuh, Y Y; Bruton, J; Williams, H L

1977-07-01

We show how zinc may easily be quantified in serum by first using an optimum concentration of guanidine hydrochloride to cause release of zinc from proteins, followed by complexation of released metals with cyanide. The cyanide complex of zinc is preferentially demasked with chloral hydrate, followed by a colorimetric reaction between zinc and 4-(2-pyridylazo)resorcinol. This is a sensitive water-soluble ligand; its complex with zinc has an absorption maximum at 497 nm. Values found by this technique compare favorably with those obtained by atomic absorption spectroscopy.

Exciplex electroluminescence and photoluminescence spectra of the new organic materials based on zinc complexes of sulphanylamino-substituted ligands.

Science.gov (United States)

Kaplunov, Mikhail G; Krasnikova, Svetlana S; Nikitenko, Sergey L; Sermakasheva, Natalia L; Yakushchenko, Igor K

2012-04-03

We have investigated the electroluminescence spectra of the electroluminescent devices based on the new zinc complexes of amino-substituted benzothiazoles and quinolines containing the C-N-M-N chains in their chelate cycles. The spectra exhibit strong exciplex bands in the green to yellow region 540 to 590 nm due to interaction of the excited states of zinc complexes and triaryl molecules of the hole-transporting layer. For some devices, the intrinsic luminescence band of 460 nm in the blue region is also observed along with the exciplex band giving rise to an almost white color of the device emission. The exciplex band can be eliminated if the material of the hole-transporting layer is not a triarylamine derivative. We have also found the exciplex emission in the photoluminescence spectra of the films containing blends of zinc complex and triphenylamine material.

Facile Preparation of Hybrid Zinc Porphyrin Dendrimer Using Coordination Complex

Energy Technology Data Exchange (ETDEWEB)

Choi, Go-Eun; Shin, Eun Ju [Sunchon National University, Suncheon (Korea, Republic of)

2016-03-15

Porphyrins and metalloporphyrins have been investigated extensively due to their important role in natural photosynthesis, strong absorption in visible region, good light-harvesting properties, unique photophysical and electrochemical properties, and the development of simple synthetic routes for various derivatives. Dendrimers have globular structure with branches of repeating units and wide diversity of the architecture because their size, shape, and functionalities can be tailored. Numerous dendrimers have been designed and synthesized for various applications ranging from catalyst to drug delivery. Both pyridine dendrons Py-PD and Py-AD were successfully coordinated at axial position on central zinc metal cation in zinc porphyrin dendrimers ZnP-AD, ZnP-AD2, or ZnP-AD4. Therefore, it was proven that the formation of axial coordination complex between metal-centered dendrimer and ligand-containing dendron provides another facile method for the preparation of new hybrid dendrimer.

Soybean extracts increase cell surface ZIP4 abundance and cellular zinc levels: a potential novel strategy to enhance zinc absorption by ZIP4 targeting.

Science.gov (United States)

Hashimoto, Ayako; Ohkura, Katsuma; Takahashi, Masakazu; Kizu, Kumiko; Narita, Hiroshi; Enomoto, Shuichi; Miyamae, Yusaku; Masuda, Seiji; Nagao, Masaya; Irie, Kazuhiro; Ohigashi, Hajime; Andrews, Glen K; Kambe, Taiho

2015-12-01

Dietary zinc deficiency puts human health at risk, so we explored strategies for enhancing zinc absorption. In the small intestine, the zinc transporter ZIP4 functions as an essential component of zinc absorption. Overexpression of ZIP4 protein increases zinc uptake and thereby cellular zinc levels, suggesting that food components with the ability to increase ZIP4 could potentially enhance zinc absorption via the intestine. In the present study, we used mouse Hepa cells, which regulate mouse Zip4 (mZip4) in a manner indistinguishable from that in intestinal enterocytes, to screen for suitable food components that can increase the abundance of ZIP4. Using this ZIP4-targeting strategy, two such soybean extracts were identified that were specifically able to decrease mZip4 endocytosis in response to zinc. These soybean extracts also effectively increased the abundance of apically localized mZip4 in transfected polarized Caco2 and Madin-Darby canine kidney cells and, moreover, two apically localized mZip4 acrodermatitis enteropathica mutants. Soybean components were purified from one extract and soyasaponin Bb was identified as an active component that increased both mZip4 protein abundance and zinc levels in Hepa cells. Finally, we confirmed that soyasaponin Bb is capable of enhancing cell surface endogenous human ZIP4 in human cells. Our results suggest that ZIP4 targeting may represent a new strategy to improve zinc absorption in humans. © 2015 Authors; published by Portland Press Limited.

Toxic and nontoxic components of botulinum neurotoxin complex are evolved from a common ancestral zinc protein

International Nuclear Information System (INIS)

Inui, Ken; Sagane, Yoshimasa; Miyata, Keita; Miyashita, Shin-Ichiro; Suzuki, Tomonori; Shikamori, Yasuyuki; Ohyama, Tohru; Niwa, Koichi; Watanabe, Toshihiro

2012-01-01

Highlights: ► BoNT and NTNHA proteins share a similar protein architecture. ► NTNHA and BoNT were both identified as zinc-binding proteins. ► NTNHA does not have a classical HEXXH zinc-coordinating motif similar to that found in all serotypes of BoNT. ► Homology modeling implied probable key residues involved in zinc coordination. -- Abstract: Zinc atoms play an essential role in a number of enzymes. Botulinum neurotoxin (BoNT), the most potent toxin known in nature, is a zinc-dependent endopeptidase. Here we identify the nontoxic nonhemagglutinin (NTNHA), one of the BoNT-complex constituents, as a zinc-binding protein, along with BoNT. A protein structure classification database search indicated that BoNT and NTNHA share a similar domain architecture, comprising a zinc-dependent metalloproteinase-like, BoNT coiled-coil motif and concanavalin A-like domains. Inductively coupled plasma-mass spectrometry analysis demonstrated that every single NTNHA molecule contains a single zinc atom. This is the first demonstration of a zinc atom in this protein, as far as we know. However, the NTNHA molecule does not possess any known zinc-coordinating motif, whereas all BoNT serotypes possess the classical HEXXH motif. Homology modeling of the NTNHA structure implied that a consensus K-C-L-I-K-X 35 -D sequence common among all NTNHA serotype molecules appears to coordinate a single zinc atom. These findings lead us to propose that NTNHA and BoNT may have evolved distinct functional specializations following their branching out from a common ancestral zinc protein.

Surface passivation of high purity granular metals: zinc, cadmium, lead

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Pirozhenko L. A.

2017-10-01

Full Text Available For the high purity metals (99.9999%, such as zinc, cadmium, and lead, which are widely used as initial components in growing semiconductor and scintillation crystals (CdTe, CdZnTe, ZnSe, (Cd, Zn, Pb WO4, (Cd, Zn, Pb MoO4 et al., it is very important to ensure reliable protection of the surface from oxidation and adsorption of impurities from the atmosphere. The specific features of surface passivation of high purity cadmium, lead and zinc are not sufficiently studied and require specific methodologies for further studies. The use of organic solutions in the schemes of chemical passivation of the investigated metals avoids hydrolysis of the obtained protective films. The use of organic solvents with pure cation and anion composition as the washing liquid prevents chemisorption of ions present in the conventionally used distilled water. This keeps the original purity of the granular metals. Novel compositions of etchants and etching scheme providing simultaneous polishing and passivation of high purity granular Zn, Cd and Pb are developed. Chemical passivation allows storing metals in the normal atmospheric conditions for more than half a year for Zn and Cd and up to 30 days for Pb without changing the state of the surface. The use of the glycerol-DMF solution in the processes for obtaining Pb granules provides self-passivation of metal surfaces and eliminates the additional chemical processing while maintaining the quality of corrosion protection.

Highly microporous carbons derived from a complex of glutamic acid and zinc chloride for use in supercapacitors

Science.gov (United States)

Dong, Xiao-Ling; Lu, An-Hui; He, Bin; Li, Wen-Cui

2016-09-01

The selection of carbon precursor is an important factor when designing carbon materials. In this study, a complex derived from L-glutamic acid and zinc chloride was used to prepare highly microporous carbons via facile pyrolysis. L-glutamic acid, a new carbon precursor with nitrogen functionality, coordinated with zinc chloride resulted in a homogeneous distribution of Zn2+ on the molecular level. During pyrolysis, the evaporation of the in situ formed zinc species creates an abundance of micropores together with the inert gases. The obtained carbons exhibit high specific surface area (SBET: 1203 m2 g-1) and a rich nitrogen content (4.52 wt%). In excess of 89% of the pore volume consists of micropores with pore size ranging from 0.5 to 1.2 nm. These carbons have been shown to be suitable for use as supercapacitor electrodes, and have been tested in 6 M KOH where a capacitance of 217 F g-1 was achieved at a current density of 0.5 A g-1. A long cycling life of 30 000 cycles was achieved at a current density of 1 A g-1, with only a 9% loss in capacity. The leakage current through a two-electrode device was measured as 2.3 μA per mg of electrode and the self-discharge characteristics were minimal.

Gastroprotection studies of Schiff base zinc (II) derivative complex against acute superficial hemorrhagic mucosal lesions in rats.

Science.gov (United States)

Golbabapour, Shahram; Gwaram, Nura Suleiman; Hassandarvish, Pouya; Hajrezaie, Maryam; Kamalidehghan, Behnam; Abdulla, Mahmood Ameen; Ali, Hapipah Mohd; Hadi, A Hamid A; Majid, Nazia Abdul

2013-01-01

The study was carried out to assess the gastroprotective effect of the zinc (II) complex against ethanol-induced acute hemorrhagic lesions in rats. The animals received their respective pre-treatments dissolved in tween 20 (5% v/v), orally. Ethanol (95% v/v) was orally administrated to induce superficial hemorrhagic mucosal lesions. Omeprazole (5.790×10(-5) M/kg) was used as a reference medicine. The pre-treatment with the zinc (II) complex (2.181×10(-5) and 4.362×10(-5) M/kg) protected the gastric mucosa similar to the reference control. They significantly increased the activity levels of nitric oxide, catalase, superoxide dismutase, glutathione and prostaglandin E2, and decreased the level of malondialdehyde. The histology assessments confirmed the protection through remarkable reduction of mucosal lesions and increased the production of gastric mucosa. Immunohistochemistry and western blot analysis indicated that the complex might induced Hsp70 up-regulation and Bax down-regulation. The complex moderately increased the gastroprotectiveness in fine fettle. The acute toxicity approved the non-toxic characteristic of the complex (<87.241×10(-5) M/kg). The gastroprotective effect of the zinc (II) complex was mainly through its antioxidant activity, enzymatic stimulation of prostaglandins E2, and up-regulation of Hsp70. The gastric wall mucus was also a remarkable protective mechanism.

A Rac1--GDP trimer complex binds zinc with tetrahedral and octahedral coordination, displacing magnesium

Energy Technology Data Exchange (ETDEWEB)

Prehna, G.; Stebbins, C

2007-01-01

The Rho family of small GTPases represent well characterized signaling molecules that regulate many cellular functions such as actin cytoskeletal arrangement and the cell cycle by acting as molecular switches. A Rac1-GDP-Zn complex has been crystallized in space group P3221 and its crystal structure has been solved at 1.9 {angstrom} resolution. These trigonal crystals reveal the unexpected ability of Rac1 to coordinate Zn atoms in a tetrahedral fashion by use of its biologically relevant switch I and switch II regions. Upon coordination of zinc, the switch I region is stabilized in the GDP-bound conformation and contributes to a Rac1 trimer in the asymmetric unit. Zinc coordination causes switch II to adopt a novel conformation with a symmetry-related molecule. Additionally, zinc was found to displace magnesium from its octahedral coordination at switch I, although GDP binding remained stable. This structure represents the first reported Rac1-GDP-Zn complex, which further underscores the conformational flexibility and versatility of the small GTPase switch regions.

A Rac1-GDP Trimer Complex Binds Zinc with Tetrahedral and Octahedral Coordination, Displacing Magnesium

Energy Technology Data Exchange (ETDEWEB)

Prehna,G.; Stebbins, E.

2007-01-01

The Rho family of small GTPases represent well characterized signaling molecules that regulate many cellular functions such as actin cytoskeletal arrangement and the cell cycle by acting as molecular switches. A Rac1-GDP-Zn complex has been crystallized in space group P3{sub 2}21 and its crystal structure has been solved at 1.9 {angstrom} resolution. These trigonal crystals reveal the unexpected ability of Rac1 to coordinate Zn atoms in a tetrahedral fashion by use of its biologically relevant switch I and switch II regions. Upon coordination of zinc, the switch I region is stabilized in the GDP-bound conformation and contributes to a Rac1 trimer in the asymmetric unit. Zinc coordination causes switch II to adopt a novel conformation with a symmetry-related molecule. Additionally, zinc was found to displace magnesium from its octahedral coordination at switch I, although GDP binding remained stable. This structure represents the first reported Rac1-GDP-Zn complex, which further underscores the conformational flexibility and versatility of the small GTPase switch regions.

Toxic and nontoxic components of botulinum neurotoxin complex are evolved from a common ancestral zinc protein

Energy Technology Data Exchange (ETDEWEB)

Inui, Ken [Department of Food and Cosmetic Science, Faculty of Bioindustry, Tokyo University of Agriculture, 196 Yasaka, Abashiri 099-2493 (Japan); Japan Society for the Promotion of Science, 1-8 Chiyoda-ku, Tokyo 102-8472 (Japan); Sagane, Yoshimasa [Department of Food and Cosmetic Science, Faculty of Bioindustry, Tokyo University of Agriculture, 196 Yasaka, Abashiri 099-2493 (Japan); Miyata, Keita [Department of Food and Cosmetic Science, Faculty of Bioindustry, Tokyo University of Agriculture, 196 Yasaka, Abashiri 099-2493 (Japan); Japan Society for the Promotion of Science, 1-8 Chiyoda-ku, Tokyo 102-8472 (Japan); Miyashita, Shin-Ichiro [Department of Food and Cosmetic Science, Faculty of Bioindustry, Tokyo University of Agriculture, 196 Yasaka, Abashiri 099-2493 (Japan); Suzuki, Tomonori [Department of Bacteriology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558 (Japan); Shikamori, Yasuyuki [Agilent Technologies International Japan, Ltd. Takaura-cho 9-1, Hachioji-shi, Tokyo 192-0033 (Japan); Ohyama, Tohru; Niwa, Koichi [Department of Food and Cosmetic Science, Faculty of Bioindustry, Tokyo University of Agriculture, 196 Yasaka, Abashiri 099-2493 (Japan); Watanabe, Toshihiro, E-mail: t-watana@bioindustry.nodai.ac.jp [Department of Food and Cosmetic Science, Faculty of Bioindustry, Tokyo University of Agriculture, 196 Yasaka, Abashiri 099-2493 (Japan)

2012-03-16

Highlights: Black-Right-Pointing-Pointer BoNT and NTNHA proteins share a similar protein architecture. Black-Right-Pointing-Pointer NTNHA and BoNT were both identified as zinc-binding proteins. Black-Right-Pointing-Pointer NTNHA does not have a classical HEXXH zinc-coordinating motif similar to that found in all serotypes of BoNT. Black-Right-Pointing-Pointer Homology modeling implied probable key residues involved in zinc coordination. -- Abstract: Zinc atoms play an essential role in a number of enzymes. Botulinum neurotoxin (BoNT), the most potent toxin known in nature, is a zinc-dependent endopeptidase. Here we identify the nontoxic nonhemagglutinin (NTNHA), one of the BoNT-complex constituents, as a zinc-binding protein, along with BoNT. A protein structure classification database search indicated that BoNT and NTNHA share a similar domain architecture, comprising a zinc-dependent metalloproteinase-like, BoNT coiled-coil motif and concanavalin A-like domains. Inductively coupled plasma-mass spectrometry analysis demonstrated that every single NTNHA molecule contains a single zinc atom. This is the first demonstration of a zinc atom in this protein, as far as we know. However, the NTNHA molecule does not possess any known zinc-coordinating motif, whereas all BoNT serotypes possess the classical HEXXH motif. Homology modeling of the NTNHA structure implied that a consensus K-C-L-I-K-X{sub 35}-D sequence common among all NTNHA serotype molecules appears to coordinate a single zinc atom. These findings lead us to propose that NTNHA and BoNT may have evolved distinct functional specializations following their branching out from a common ancestral zinc protein.

Performance of Grass Filter Strip in Copper and Zinc Removal in Surface and Subsurface Runoff

Directory of Open Access Journals (Sweden)

Huo Weijie

2017-01-01

Full Text Available Three filter strips were conducted on self-designed soil bins. Taking a filter strip with no vegetation as contrast, the effectiveness of vegetation and soil conditions on heavy metals (including copper and zinc removal efficiencies were investigated by simulated runoff experiment. The results showed that the adsorbed state is the main existing form of heavy metal. For surface runoff, most of total copper and total zinc are trapped in first 4m and it is ineffective to increase the distance beyond 4m for removal. Vegetation has no significant effect on total copper and total zinc removal, while the soil with higher content of organic matter is contributing to total Zn interception. For subsurface runoff, the removal efficiencies of total copper and total zinc can reach to above 95.38% and both vegetation and soil conditions have no significant effects. Vegetation is contributing to copper ion and zinc ion removal significantly. Soil condition is only a significant factor to zinc ion, with higher content of organic matter as a contributing factor.

Fabrication and characterization of organic light-emitting diodes using zinc complexes as hole-blocking layer.

Science.gov (United States)

Kim, Won Sam; You, Jung Min; Lee, Burm-Jong; Jang, Yoon-Ki; Kim, Dong-Eun; Kwon, Young-Soo

2006-11-01

2-(2-Hydroxyphenyl)benzoxazole (HPB) was employed as organic ligand and the corresponding zinc complexes (Zn(HPB)2 and Zn(HPB)q) were synthesized. And their EL properties were characterized. The structures of zinc complexes were determined with FT-NMR, FT-IR, UV-Vis, and XPS. The thermal stability showed up to about 300 degrees C under nitrogen flow, which was measured by TGA. The photoluminescence (PL) of zinc complexes were measured from the DMF solution. The PL emitted in blue and yellow region, respectively. The EL devices were fabricated by the vacuum deposition. Two kinds of OLEDs devices were fabricated; ITO/NPB (40 nm)/Zn complexes (60 nm)/LiF/Al and ITO/NPB (40 nm)/Alq3 (60 nm)/Zn complexes (5 nm)/LiF/Al. Both of the EL properties as the emitting and the hole-blocking layer were investigated. The EL emission of Zn(HPB)q exhibited green light centered at 532 nm. The device showed a turn-on voltage at 5 V and a luminance of 6073 cd/m2 at 10 V. Meanwhile, the maximum EL the emission of the Zn(HPB)2 device was found to be at 447 nm. And the device showed a luminance of 2813 cd/m2 at 10 V. The ITO/NPB (40 nm)/Alq3 (60 nm)/Zn(HPB)2 (5 nm)/LiF/Al device showed increased luminance of L=17000 cd/m2 compared to L=12000 cd/m2 for similar device fabricated without the hole-blocking layer. And the turn-on voltage was significantly affected by the existence of the hole-blocking layer.

Zinc Enolate/Sulfinate Prepared from a Single-Run Reaction Using Zinc Dust with O-Tosylated 4-Hydroxy Coumarin and Pyrone

Energy Technology Data Exchange (ETDEWEB)

Shin, Ueon Sang; Joo, Seong-Ryu; Kim, Seung-Hoi [Dankook University, Cheonan (Korea, Republic of)

2016-07-15

We demonstrated the preparation of new zinc complexes, 2-oxo-2H-chromen-4-yloxy tosylzinc (I), and 6-methyl-2-oxo-2H-pyran-4-yloxy tosylzinc (II), by the oxidative addition of readily available zinc dust into the corresponding 4-tosylated coumarin (A) and pyrone (B), respectively. Of special interest, the thus-obtained zinc complexes showed an electrophile-dependent reactivity. The subsequent coupling reactions of I and II with a variety of acid chlorides provided the O-acylation product in moderate yields. More interestingly, it should be emphasized that the thus-prepared zinc complexes (I and II) functioned both as zinc enolate and zinc sulfinate, providing C(3)-disubstituted product (b) and sulfone (c), respectively, from a single-run reaction when I or II was treated with benzyl halides. Even though somewhat low yields were achieved under the nonoptimized conditions, the novel zinc complexes present another potential application for zinc reagents. Versatile applications of this discovery are currently underway.

Zinc Enolate/Sulfinate Prepared from a Single-Run Reaction Using Zinc Dust with O-Tosylated 4-Hydroxy Coumarin and Pyrone

International Nuclear Information System (INIS)

Shin, Ueon Sang; Joo, Seong-Ryu; Kim, Seung-Hoi

2016-01-01

We demonstrated the preparation of new zinc complexes, 2-oxo-2H-chromen-4-yloxy tosylzinc (I), and 6-methyl-2-oxo-2H-pyran-4-yloxy tosylzinc (II), by the oxidative addition of readily available zinc dust into the corresponding 4-tosylated coumarin (A) and pyrone (B), respectively. Of special interest, the thus-obtained zinc complexes showed an electrophile-dependent reactivity. The subsequent coupling reactions of I and II with a variety of acid chlorides provided the O-acylation product in moderate yields. More interestingly, it should be emphasized that the thus-prepared zinc complexes (I and II) functioned both as zinc enolate and zinc sulfinate, providing C(3)-disubstituted product (b) and sulfone (c), respectively, from a single-run reaction when I or II was treated with benzyl halides. Even though somewhat low yields were achieved under the nonoptimized conditions, the novel zinc complexes present another potential application for zinc reagents. Versatile applications of this discovery are currently underway

Structural zinc(II thiolate complexes relevant to the modeling of Ada repair protein: Application toward alkylation reactions

Directory of Open Access Journals (Sweden)

Mohamed M. Ibrahim

2014-11-01

Full Text Available The TtZn(II-bound perchlorate complex [TtZn–OClO3] 1 (Ttxyly = hydrotris[N-xylyl-thioimidazolyl]borate was used for the synthesis of zinc(II-bound ethanthiothiol complex [TtZn–SCH2CH3] 2 and its hydrogen-bond containing analog Tt–ZnSCH2CH2–NH(COOC(CH33 3. These thiolate complexes were examined as structural models for the active sites of Ada repair protein toward methylation reactions. The Zn[S3O] coordination sphere in complex 1 includes three thione donors from the ligand Ttixyl and one oxygen donor from the perchlorate coligand in ideally tetrahedral arrangement around the zinc center. The average Zn(1–S(thione bond length is 2.344 Å, and the Zn(1–O(1 bond length is 1.917 Å.

Neodymium conversion layers formed on zinc powder for improving electrochemical properties of zinc electrodes

International Nuclear Information System (INIS)

Zhu Liqun; Zhang Hui; Li Weiping; Liu Huicong

2008-01-01

Zinc powder, as active material of secondary alkaline zinc electrode, can greatly limit the performance of zinc electrode due to corrosion and dendritic growth of zinc resulting in great capacity-loss and short cycle life of the electrode. This work is devoted to modification study of zinc powder with neodymium conversion films coated directly onto it using ultrasonic immersion method for properties improvement of zinc electrodes. Scanning electron microscopy and other characterization techniques are applied to prove that neodymium conversion layers are distributing on the surface of modified zinc powder. The electrochemical performance of zinc electrodes made of such modified zinc powder is investigated through potentiodynamic polarization, potentiostatic polarization and cyclic voltammetry. The neodymium conversion films are found to have a significant effect on inhibition corrosion capability of zinc electrode in a beneficial way. It is also confirmed that the neodymium conversion coatings can obviously suppress dendritic growth of zinc electrode, which is attributed to the amelioration of deposition state of zinc. Moreover, the results of cyclic voltammetry reveal that surface modification of zinc powder enhances the cycle performance of the electrode mainly because the neodymium conversion films decrease the amounts of ZnO or Zn(OH) 2 dissolved in the electrolyte

Transition metal complexes with pyrazole-based ligands.Part 29. Reactions of zinc(II and mercury(II thiocyanate with 4-acetyl-3-amino-5-methylpyrazole

Directory of Open Access Journals (Sweden)

KATALIN MÉSZÁROS SZÉCSÉNYI

2009-11-01

Full Text Available The work is concerned with the crystal and molecular structures of zinc(II and mercury(II complexes with 4-acetyl-3-amino-5-methyl-pyrazole (aamp of the coordination formulae [Zn(NCS2(aamp2] and (Haamp2[Hg(SCN4]. The zinc(II complex was obtained by the reaction of a warm methanolic solution of aamp with a mixture of zinc(II nitrate and ammonium thiocyanate, whereas the mercury(II complex was prepared by the reaction of a warm ethanolic solution of aamp and a warm, slightly acidified aqueous solution of [Hg(SCN4]2-. Both complexes have a tetrahedral geometry, which in the case of zinc complex is formed by monodentate coordination of two aamp molecules and two isothiocyanate groups. The Zn(II and Hg(II atoms have significantly deformed coordination geometry. In both crystal structures the pyrazole derivative has a planar form, probably stabilized by an intramolecular N–H···O hydrogen bond. Apart from the X-ray structural analysis, the isolated complexes were characterized by elemental analysis, IR spectroscopy, conductometric measurements and thermal analysis.

Role of zinc-protein complexes in the serum of human beings with reference to health and infectious diseases

International Nuclear Information System (INIS)

Bibi, S.; Sajjad, I.; Akram, W.; Viqar, N.; Iqbal, M.S.; Iqbal, M.Z.

1997-01-01

Serum of one hundred thirty normal subjects and 100 patients of different infections were analysed by electrophoresis and atomic absorption flame spectrophotometric technique. It was found that about sixty percent of zinc is bound to albumin and thirty percent is bound to alpha 2-globulins with a variation of 2-5%, beta-globulins and gamma-globulins with a variation of 2-5% in different normal subjects. While the determination of zinc in patients of different infections shows 20-30% decrease in the concentration of albumin bound zinc. The concentration of zinc in alpha 2-globulins remains the same in normal subjects as well as in patients of different infections. The results indicate that in low nourished normal subjects, there is a low concentration of zinc complexes of albumin and a greater chance of different infectious diseases it was further known that albumin works for the transport of zinc and possibly, alpha 2-globulins plays on intermediate role for the attachment of zinc to different body organs. From the above determinations, it is clear that it is the low concentration of zinc in normal subjects which favours the attack of infectious disease. So higher levels of zinc in serum means more resistance towards the attack of infectious diseases. (author)

Characterization and Influence of Green Synthesis of Nano-Sized Zinc Complex with 5-Aminolevulinic Acid on Bioactive Compounds of Aniseed.

Science.gov (United States)

Tavallali, Vahid; Rahmati, Sadegh; Rowshan, Vahid

2017-11-01

A new water soluble zinc-aminolevulinic acid nano complex (n[Zn(ALA) 2 ]), which was characterized by TEM, IR, and EDX spectra, has been prepared via sonochemical method under green conditions in water. In the current study, the effectiveness of foliar Zn amendment using synthetic Zn-ALA nano complex, as a new introduced Zn-fertilizer here, was evaluated. As the model plant, Pimpinella anisum, the most valuable spice and medicinal plant grown in warm regions, was used. By using zinc nano complex, further twenty compounds were obtained in the essential oil of anise plants. Application of 0.2% (w/v) Zn-ALA nano complex increased the levels of (E)-anethole, β-bisabolene, germacrene D, methyl chavicol, and α-zingiberene in the essential oil. Nano Zn complex at the rate of 0.2% induced considerable high phenolic compounds and zinc content of shoots and seeds. Chlorogenic acid had the highest level between four detected phenolic compounds. The maximum antioxidant activity was monitored through the application of Zn nano complex. According to the results, nanoscale nutrients can be provided with further decreased doses for medicinal plants. Using Zn-ALA nano complex is a new and efficient method to improve the pharmaceutical and food properties of anise plants. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

Cathodic hydrogen charging of zinc

International Nuclear Information System (INIS)

Panagopoulos, C.N.; Georgiou, E.P.; Chaliampalias, D.

2014-01-01

Highlights: •Incorporation of hydrogen into zinc and formation of zinc hydrides. •Investigation of surface residual stresses due to hydrogen diffusion. •Effect of hydrogen diffusion and hydride formation on mechanical properties of Zn. •Hydrogen embrittlement phenomena in zinc. -- Abstract: The effect of cathodic hydrogen charging on the structural and mechanical characteristics of zinc was investigated. Hardening of the surface layers of zinc, due to hydrogen incorporation and possible formation of ZnH 2 , was observed. In addition, the residual stresses brought about by the incorporation of hydrogen atoms into the metallic matrix, were calculated by analyzing the obtained X-ray diffraction patterns. Tensile testing of the as-received and hydrogen charged specimens revealed that the ductility of zinc decreased significantly with increasing hydrogen charging time, for a constant value of charging current density, and with increasing charging current density, for a constant value of charging time. However, the ultimate tensile strength of this material was slightly affected by the hydrogen charging procedure. The cathodically charged zinc exhibited brittle transgranular fracture at the surface layers and ductile intergranular fracture at the deeper layers of the material

Preparation and Wetting Behavior of Lyophobic Surface on Zinc Substrate

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HAN Xiang-xiang

2018-03-01

Full Text Available Micro-nano structure on zinc substrate was fabricated through the combination of chemical etching with hydrochloric acid aqueous solution and hydrothermal reaction. After modification with perfluorooctanoic solution, the lyophobic surface was prepared. The phase composition, microstructure, chemical composition, and wettability of the as-obtained surface were investigated by X-ray diffractometer, scanning electron microscope, Fourier transform infrared spectrometer, and contact angle tester. The results show that a layer of ZnO nano-rods grows on the surface of the submicrometer structure, and exhibits good resistance to water impact and stability under the combined action of low surface energy material. When hydrochloric acid concentration is 1.0mol/L and hydrothermal reaction temperature is 95℃, the lyophobic surface possesses the best morphology of ZnO nano-rods. The maximum contact angles of distilled water and peanut oil are 154.65° and 144.65°, respectively, and the sliding angle is less than 10°.

A review of zinc oxide mineral beneficiation using flotation method.

Science.gov (United States)

Ejtemaei, Majid; Gharabaghi, Mahdi; Irannajad, Mehdi

2014-04-01

In recent years, extraction of zinc from low-grade mining tailings of oxidized zinc has been a matter of discussion. This is a material which can be processed by flotation and acid-leaching methods. Owing to the similarities in the physicochemical and surface chemistry of the constituent minerals, separation of zinc oxide minerals from their gangues by flotation is an extremely complex process. It appears that selective leaching is a promising method for the beneficiation of this type of ore. However, with the high consumption of leaching acid, the treatment of low-grade oxidized zinc ores by hydrometallurgical methods is expensive and complex. Hence, it is best to pre-concentrate low-grade oxidized zinc by flotation and then to employ hydrometallurgical methods. This paper presents a critical review on the zinc oxide mineral flotation technique. In this paper, the various flotation methods of zinc oxide minerals which have been proposed in the literature have been detailed with the aim of identifying the important factors involved in the flotation process. The various aspects of recovery of zinc from these minerals are also dealt with here. The literature indicates that the collector type, sulfidizing agent, pH regulator, depressants and dispersants types, temperature, solid pulp concentration, and desliming are important parameters in the process. The range and optimum values of these parameters, as also the adsorption mechanism, together with the resultant flotation of the zinc oxide minerals reported in the literature are summarized and highlighted in the paper. This review presents a comprehensive scientific guide to the effectiveness of flotation strategy. Copyright © 2013 Elsevier B.V. All rights reserved.

Zinc electrode - its behaviour in the nickel oxide-zinc accumulator

Energy Technology Data Exchange (ETDEWEB)

1984-01-01

Certain aspects of zinc electrode reaction and behavior are investigated in view of their application to batteries. The properties of the zinc electrode in a battery system are discussed, emphasizing porous structure. Shape change is emphasized as the most important factor leading to limited battery cycle life. It is shown that two existing models of shape change based on electroosmosis and current distribution are unable to consistently describe observed phenomena. The first stages of electrocrystallization are studied and the surface reactions between the silver substrate and the deposited zinc layer are investigated. The reaction mechanism of zinc and amalgamated zinc in an alkaline electrolyte is addressed, and the batter system is studied to obtain information on cycling behavior and on the shape change phenomenon. The effect on cycle behavior of diferent amalgamation techniques of the zinc electrode and several additives is addressed. Impedance measurements on zinc electrodes are considered, and battery behavior is correlated with changes in the zinc electrode during cycling. 193 references.

The degradation of lining of rotary furnaces in the production of zinc oxide

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Natália Luptáková

2014-06-01

Full Text Available This paper is closely connected with the complex problem of degradation relating to the refractories of rotary furnace linings in the production of zinc oxide. Zinc oxide can be produced by variety of ways, but the most common method of production which is used in Europe is indirect, i.e. pyrolytic combustion of zinc. This method is also called "French process" of manufacturing ZnO. But this mentioned method of preparation leads to the creation of the enormous amount of zinc slag including chemical complexes of elements Fe, Zn and Al. The mechanism of degradation of the lining leads to slag rests and it is closely connected with the mutual interaction of the aggressive agents with the components of the lining. This process creates a new undesired surface layer which increased the overall thickness of zinc slag. Stuck slag has the influence on rapid degradation of the linings and moreover it also decreases the production quality of ZnO. Analysis results introduced in this paper are significant information for minimizing of degradation of rotary furnaces.  

Horse Liver Alcohol Dehydrogenase: Zinc Coordination and Catalysis

Energy Technology Data Exchange (ETDEWEB)

Plapp, Bryce V.; Savarimuthu, Baskar Raj; Ferraro, Daniel J.; Rubach, Jon K.; Brown, Eric N.; Ramaswamy, S. (Iowa)

2017-07-07

During catalysis by liver alcohol dehydrogenase (ADH), a water bound to the catalytic zinc is replaced by the oxygen of the substrates. The mechanism might involve a pentacoordinated zinc or a double-displacement reaction with participation by a nearby glutamate residue, as suggested by studies of human ADH3, yeast ADH1, and some other tetrameric ADHs. Zinc coordination and participation of water in the enzyme mechanism were investigated by X-ray crystallography. The apoenzyme and its complex with adenosine 5'-diphosphoribose have an open protein conformation with the catalytic zinc in one position, tetracoordinated by Cys-46, His-67, Cys-174, and a water molecule. The bidentate chelators 2,2'-bipyridine and 1,10-phenanthroline displace the water and form a pentacoordinated zinc. The enzyme–NADH complex has a closed conformation similar to that of ternary complexes with coenzyme and substrate analogues; the coordination of the catalytic zinc is similar to that found in the apoenzyme, except that a minor, alternative position for the catalytic zinc is ~1.3 Å from the major position and closer to Glu-68, which could form the alternative coordination to the catalytic zinc. Complexes with NADH and N-1-methylhexylformamide or N-benzylformamide (or with NAD+ and fluoro alcohols) have the classical tetracoordinated zinc, and no water is bound to the zinc or the nicotinamide rings. The major forms of the enzyme in the mechanism have a tetracoordinated zinc, where the carboxylate group of Glu-68 could participate in the exchange of water and substrates on the zinc. Hydride transfer in the Michaelis complexes does not involve a nearby water.

Zinc in Cellular Regulation: The Nature and Significance of "Zinc Signals".

Science.gov (United States)

Maret, Wolfgang

2017-10-31

In the last decade, we witnessed discoveries that established Zn 2+ as a second major signalling metal ion in the transmission of information within cells and in communication between cells. Together with Ca 2+ and Mg 2+ , Zn 2+ covers biological regulation with redox-inert metal ions over many orders of magnitude in concentrations. The regulatory functions of zinc ions, together with their functions as a cofactor in about three thousand zinc metalloproteins, impact virtually all aspects of cell biology. This article attempts to define the regulatory functions of zinc ions, and focuses on the nature of zinc signals and zinc signalling in pathways where zinc ions are either extracellular stimuli or intracellular messengers. These pathways interact with Ca 2+ , redox, and phosphorylation signalling. The regulatory functions of zinc require a complex system of precise homeostatic control for transients, subcellular distribution and traffic, organellar homeostasis, and vesicular storage and exocytosis of zinc ions.

Directed spatial organization of zinc oxide nanostructures

Science.gov (United States)

Hsu, Julia [Albuquerque, NM; Liu, Jun [Richland, WA

2009-02-17

A method for controllably forming zinc oxide nanostructures on a surface via an organic template, which is formed using a stamp prepared from pre-defined relief structures, inking the stamp with a solution comprising self-assembled monolayer (SAM) molecules, contacting the stamp to the surface, such as Ag sputtered on Si, and immersing the surface with the patterned SAM molecules with a zinc-containing solution with pH control to form zinc oxide nanostructures on the bare Ag surface.

Synthesis and characterization of 5,7-dimethyl-8-hydroxyquinoline and 2-(2-pyridyl)benzimidazole complexes of zinc(II) for optoelectronic application

Science.gov (United States)

Singh, Kapoor; Kumar, Amit; Srivastava, Ritu; Kadyan, Partap S.; Kamalasanan, Modeeparampil N.; Singh, Ishwar

2011-11-01

Bis(5,7-dimethyl-8-hydroxyquinolinato)zinc(II) (Me 2q) 2Zn and 5,7-dimethyl-8-hydroxyquinolinato(2-(2-pyridyl)benzimidazole) zinc(II) Me 2q(pbi)Zn have been synthesized and characterized by various techniques. These metal complexes have high thermal stability (>300 °C) and high glass transition temperatures (>150 °C). The vacuum deposited films of these materials show good film forming property and are suitable for opto-electronic applications. Multilayered organic electroluminescent (EL) devices have been fabricated having structure ITO/α-NPD/zinc complex/BCP/Alq 3/LiF/Al, which produce emission with chromaticity having Commission Internationale d'Eclairage (CIE) coordinates x = 0.506 and y = 0.484 for (Me 2q) 2Zn; x = 0.47 and y = 0.52 for (Me 2q)(pbi)Zn complex. The electroluminescence spectra show peak emission centered at 572 and 561 nm respectively for these materials.

First Principles Investigation of Zinc-anode Dissolution in Zinc-air Batteries

DEFF Research Database (Denmark)

Siahrostami, Samira; Tripkovic, Vladimir; Lundgård, Keld Troen

2013-01-01

With surging interest in high energy density batteries, much attention has recently been devoted to metal-air batteries. The zinc-air battery has been known for more than hundred years and is commercially available as a primary battery, but recharging has remained elusive; in part because...... the fundamental mechanisms still remain to be fully understood. Here, we present a density functional theory investigation of the zinc dissolution (oxidation) on the anode side in the zinc-air battery. Two models are envisaged, the most stable (0001) surface and a kink surface. The kink model proves to be more....... The applied methodology provides new insight into computational modelling and design of secondary metal-air batteries....

Iron and zinc complexation in wild-type and ferritin-expressing wheat grain: implications for mineral transport into developing grain

DEFF Research Database (Denmark)

Neal, Andrew L; Geraki, Kalotina; Borg, Søren

2013-01-01

of modified complexation of both metals in transgenic grain overexpressing wheat ferritin. For zinc, there is a consistent doubling of the number of complexing phosphorus atoms. Although there is some EXAFS evidence for iron phytate in ferritin-expressing grain, there is also evidence of a structure lacking......We have used synchrotron-based X-ray fluorescence and absorption techniques to establish both metal distribution and complexation in mature wheat grains. In planta, extended X-ray absorption fine structure (EXAFS) spectroscopy reveals iron phytate and zinc phytate structures in aleurone cells...... of ferritin-expressing grains is quite different from that in wild-type grain. This may explain why the raised levels of minerals transported to the developing grain accumulate within the crease region of the transgenic grain....

Design and development of anisotropic inorganic/polystyrene nanocomposites by surface modification of zinc oxide nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Han, Xiao [School of Materials Science and Engineering, Tongji University, Shanghai 200092 (China); Research Center for Translational Medicine, East Hospital, the Institute for Biomedical Engineering & Nano Science, Tongji University School of Medicine, Shanghai 200092 (China); Huang, Shiming [Department of Physics, Tongji University, Shanghai 200092 (China); Wang, Yilong, E-mail: yilongwang@tongji.edu.cn [Research Center for Translational Medicine, East Hospital, the Institute for Biomedical Engineering & Nano Science, Tongji University School of Medicine, Shanghai 200092 (China); Shi, Donglu, E-mail: shid@ucmail.uc.edu [Research Center for Translational Medicine, East Hospital, the Institute for Biomedical Engineering & Nano Science, Tongji University School of Medicine, Shanghai 200092 (China); The Materials Science and Engineering Program, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, OH 45221 (United States)

2016-07-01

Anisotropic yolk/shell or Janus inorganic/polystyrene nanocomposites were prepared by combining miniemulsion polymerization and sol–gel reaction. The morphologies of the anisotropic composites were found to be greatly influenced by surface modification of zinc oxide (ZnO) nanoparticle seeds. Two different types of the oleic acid modified ZnO nanoparticles (OA-ZnO) were prepared by post-treatment of commercial ZnO powder and homemade OA-ZnO nanoparticles. The morphologies and properties of the nanocomposites were investigated by transmission electron microscope (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), and energy dispersive X-ray spectroscopy (EDX). It was found that both post-treated OA-ZnO and in-situ prepared OA-ZnO nanoparticles resulted in the yolk–shell and Janus structure nanocomposites, but with varied size and morphology. These nanocomposites showed stable and strong fluorescence by introducing quantum dots as the co-seeds. The fluorescent anisotropic nanocomposites were decorated separately with surface carboxyl and hydroxyl groups. These composites with unique anisotropic properties will have high potential in biomedical applications, particularly in bio-detection. - Graphical abstract: Design and development of anisotropic inorganic/polystyrene nanocomposites by surface modification of zinc oxide nanoparticles. - Highlights: • Non-magnetic anisotropic yolk/shell or Janus nanocomposites are prepared and characterized. • Different surface modification of zinc oxide (ZnO) nanoparticles results in varied morphology and size of the final product. • Fluorescent anisotropic nanocomposites embodying quantum dots are an ideal candidate for bio-detection applications.

The Effect of Tear Supplementation with 0.15% Preservative-Free Zinc-Hyaluronate on Ocular Surface Sensations in Patients with Dry Eye.

Science.gov (United States)

Perényi, Kristóf; Dienes, Lóránt; Kornafeld, Anna; Kovács, Balázs; Kiss, Huba J; Szepessy, Zsuzsanna; Nagy, Zoltán Z; Barsi, Árpád; Acosta, M Carmen; Gallar, Juana; Kovács, Illés

To evaluate the effect of tear supplementation with preservative free 0.15% zinc-hyaluronate on ocular surface sensations and corneal sensitivity in dry eye patients. Ocular surface sensations were assessed using the ocular surface disease index (OSDI) questionnaire and by recording ocular sensations during forced blinking in parallel with noninvasive tear film breakup time measurement in 20 eyes of 20 dry eye patients. Corneal sensitivity thresholds to selective stimulation of corneal mechano-, thermal- and chemical receptors were measured using the Belmonte gas esthesiometer. All baseline measurements were repeated after 1 month of treatment with 0.15% zinc-hyaluronate. After 1 month, a significant decrease in mean OSDI score (from 35.66 ± 12.36 to 15.03 ± 11.22; P  0.05). Prolonged use of 0.15% zinc-hyaluronate results in an improvement of tear film stability and a decrease of dry eye complaints. The decrease in corneal mechano-and polymodal receptor excitability suggests that zinc-hyaluronate helps to recover normal corneal sensitivity, and thus might have a beneficial additional effect on reducing ocular surface complaints in dry eye patients.

Surface nanostructuring by ion-induced localized plasma expansion in zinc oxide

Energy Technology Data Exchange (ETDEWEB)

El-Said, A. S., E-mail: elsaid@kfupm.edu.sa, E-mail: a.s.el-said@hzdr.de [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden (Germany); Physics Department, Faculty of Science, Mansoura University, 35516 Mansoura (Egypt); Moslem, W. M. [Department of Physics, Faculty of Science, Port Said University, Port Said 42521 (Egypt); Centre for Theoretical Physics, British University in Egypt (BUE), El-Shorouk City, Cairo (Egypt); Djebli, M. [Theoretical Physics Laboratory, Faculty of Physics USTHB, B.P. 32 Bab Ezzour, 16079 Algiers (Algeria)

2014-06-09

Creation of hillock-like nanostructures on the surface of zinc oxide single crystals by irradiation with slow highly charged ions is reported. At constant kinetic energy, the nanostructures were only observed after irradiation with ions of potential energies above a threshold between 19.1 keV and 23.3 keV. The size of the nanostructures increases as a function of potential energy. A plasma expansion approach is used to explain the nanostructures creation. The calculations showed that the surface nanostructures became taller with the increase of ionic temperature. The influence of charged cluster formation and the relevance of their polarity are discussed.

Surface nanostructuring by ion-induced localized plasma expansion in zinc oxide

International Nuclear Information System (INIS)

El-Said, A. S.; Moslem, W. M.; Djebli, M.

2014-01-01

Creation of hillock-like nanostructures on the surface of zinc oxide single crystals by irradiation with slow highly charged ions is reported. At constant kinetic energy, the nanostructures were only observed after irradiation with ions of potential energies above a threshold between 19.1 keV and 23.3 keV. The size of the nanostructures increases as a function of potential energy. A plasma expansion approach is used to explain the nanostructures creation. The calculations showed that the surface nanostructures became taller with the increase of ionic temperature. The influence of charged cluster formation and the relevance of their polarity are discussed.

Shaping optimal zinc coating on the surface of high-quality ductile iron casting. Part I – Moulding technologies vs. zinc coating

Directory of Open Access Journals (Sweden)

Szczęsny A.

2017-03-01

Full Text Available Studies have demonstrated that in the process of hot dip galvanizing the decisive influence on the mechanism of zinc coating formation and properties has the quality of the mechanically untreated (raw surface layer of the galvanized product. The terms “casting surface layer” denote various parameters of the microstructure, including the type of metal matrix, the number of grains and the size of graphite nodules, possible presence of hard spots (the precipitates of eutectic cementite and parameters of the surface condition. The completed research has allowed linking the manufacturing technology of ductile iron castings with the process of hot dip galvanizing.

High surface area carbon for bifunctional air electrodes applied in zinc-air batteries

Energy Technology Data Exchange (ETDEWEB)

Arai, H [on leave from NTT Laboratories (Japan); Mueller, S; Haas, O [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

Bifunctional air electrodes with high surface area carbon substrates showed low reduction overpotential, thus are promising for enhancing the energy efficiency and power capability of zinc-air batteries. The improved performance is attributed to lower overpotential due to diffusion of the reaction intermediate, namely the peroxide ion. (author) 1 fig., 2 refs.

Zinc isotope investigation of surface and pore waters in a mountain watershed impacted by acid rock drainage.

Science.gov (United States)

Aranda, Suzan; Borrok, David M; Wanty, Richard B; Balistrieri, Laurie S

2012-03-15

The pollution of natural waters with metals derived from the oxidation of sulfide minerals like pyrite is a global environmental problem. However, the metal loading pathways and transport mechanisms associated with acid rock drainage reactions are often difficult to characterize using bulk chemical data alone. In this study, we evaluated the use of zinc (Zn) isotopes to complement traditional geochemical tools in the investigation of contaminated waters at the former Waldorf mining site in the Rocky Mountains, Colorado, U.S.A. Geochemical signatures and statistical analysis helped in identifying two primary metal loading pathways at the Waldorf site. The first was characterized by a circumneutral pH, high alkalinity, and high Zn/Cd ratios. The second was characterized by acidic pHs and low Zn/Cd ratios. Zinc isotope signatures in surface water samples collected across the site were remarkably similar (the δ(66)Zn, relative to JMC 3-0749-L, for most samples ranged from 0.20 to 0.30‰±0.09‰ 2σ). This probably suggests that the ultimate source of Zn is consistent across the Waldorf site, regardless of the metal loading pathway. The δ(66)Zn of pore water samples collected within a nearby metal-impacted wetland area, however, were more variable, ranging from 0.20 to 0.80‰±0.09‰ 2σ. Here the Zn isotopes seemed to reflect differences in groundwater flow pathways. However, a host of secondary processes might also have impacted Zn isotopes, including adsorption of Zn onto soil components, complexation of Zn with dissolved organic matter, uptake of Zn into plants, and the precipitation of Zn during the formation of reduced sulfur species. Zinc isotope analysis proved useful in this study; however, the utility of this isotopic tool would improve considerably with the addition of a comprehensive experimental foundation for interpreting the complex isotopic relationships found in soil pore waters. Copyright © 2012 Elsevier B.V. All rights reserved.

Enhancement in sensitivity of graphene-based zinc oxide assisted bimetallic surface plasmon resonance (SPR) biosensor

Science.gov (United States)

Kumar, Rajeev; Kushwaha, Angad S.; Srivastava, Monika; Mishra, H.; Srivastava, S. K.

2018-03-01

In the present communication, a highly sensitive surface plasmon resonance (SPR) biosensor with Kretschmann configuration having alternate layers, prism/zinc oxide/silver/gold/graphene/biomolecules (ss-DNA) is presented. The optimization of the proposed configuration has been accomplished by keeping the constant thickness of zinc oxide (32 nm), silver (32 nm), graphene (0.34 nm) layer and biomolecules (100 nm) for different values of gold layer thickness (1, 3 and 5 nm). The sensitivity of the proposed SPR biosensor has been demonstrated for a number of design parameters such as gold layer thickness, number of graphene layer, refractive index of biomolecules and the thickness of biomolecules layer. SPR biosensor with optimized geometry has greater sensitivity (66 deg/RIU) than the conventional (52 deg/RIU) as well as other graphene-based (53.2 deg/RIU) SPR biosensor. The effect of zinc oxide layer thickness on the sensitivity of SPR biosensor has also been analysed. From the analysis, it is found that the sensitivity increases significantly by increasing the thickness of zinc oxide layer. It means zinc oxide intermediate layer plays an important role to improve the sensitivity of the biosensor. The sensitivity of SPR biosensor also increases by increasing the number of graphene layer (upto nine layer).

Reactions of zinc hydride and magnesium hydride with pyridine; synthesis and characterization of 1,4-dihydro-1-pyridylzinc and -magnesium complexes

NARCIS (Netherlands)

Koning, A.J. de; Boersma, J.; Kerk, G.J.M. van der

1980-01-01

The synthesis and characterization of 1,4-dihydro-1-pyridylzinc and -magnesium complexes are described. Zinc hydride and magnesium hydride dissolve in and react with pyridine, and the reaction has been studied in detail in the case of zinc hydride. Evaporation of the solvent after 1–2 hours at 0°C

Foliar uptake of zinc by vascular plants. Radiometric study

International Nuclear Information System (INIS)

Maresova, J.; Remenarova, L.; Hornik, M.; Pipiska, M.; Augustin, J.; Lesny, J.

2012-01-01

The aim of this paper was to obtain quantitative data of foliar uptake kinetics and long distance transport of zinc in tobacco (Nicotiana tabacum L.) and hop (Humulus lupulus L.) plants. Zinc was used as a model of microelement and toxic metal, tobacco and hop as a representatives of agriculturally important plants. A tip of leaf blade was immersed in the solution spiked with 65 ZnCl 2 and foliar uptake and translocation to other parts of the plant grown in nutrient solution was measured by gamma-spectrometry and autoradiography. We found that foliar zinc uptake by both plants is dependent on the initial metal concentration within the range C 0 = 10-100 μmol dm -3 ZnCl 2 . Zinc is immobilized mainly in immersed part of the contact leaf and only 0 = 0.1 mmol dm -3 ZnCl 2 concentrations >2.5 mg/g Zn and 4.8 mg/g Zn (dry wt.) in immersed part of tobacco and hop leaf plant, respectively were found after 5 days of exposure. Low mobility of zinc entering the plant via the leaf surface can be attributed to the immobilization of zinc into Zn-ligand complexes with high stability constants log K at pH 6.0-8.0, such as the reaction products of Zn 2+ ions with citric acid, histidine or phosphates. Zinc can be extracted from dried leaves by the solutions of inorganic salts, carboxylic acids, amino acids and synthetic complexing ligands such as EDTA. Anionic (SDS) and non-ionic (Tween 40) surfactants causes the decrease of the Zn foliar uptake, but not translocation of Zn from the contact leaf area. Obtained data are discussed from the point of view of possible limited efficiency of liquid formulations designed for practical applications as Zn foliar fertilizers. (author)

Zinc-enriched boutons in rat spinal cord

DEFF Research Database (Denmark)

Schrøder, H D; Danscher, G; Jo, S M

2000-01-01

The rat spinal cord reveals a complex pattern of zinc-enriched (ZEN) boutons. As a result of in vivo exposure to selenide ions, nanosized clusters of zinc selenide are created in places where zinc ions are present, including the zinc-containing synaptic vesicles of ZEN boutons. The clusters can...

Transformation of zinc hydroxide chloride monohydrate to crystalline zinc oxide.

Science.gov (United States)

Moezzi, Amir; Cortie, Michael; McDonagh, Andrew

2016-04-25

Thermal decomposition of layered zinc hydroxide double salts provides an interesting alternative synthesis for particles of zinc oxide. Here, we examine the sequence of changes occurring as zinc hydroxide chloride monohydrate (Zn5(OH)8Cl2·H2O) is converted to crystalline ZnO by thermal decomposition. The specific surface area of the resultant ZnO measured by BET was 1.3 m(2) g(-1). A complicating and important factor in this process is that the thermal decomposition of zinc hydroxide chloride is also accompanied by the formation of volatile zinc-containing species under certain conditions. We show that this volatile compound is anhydrous ZnCl2 and its formation is moisture dependent. Therefore, control of atmospheric moisture is an important consideration that affects the overall efficiency of ZnO production by this process.

The relative efficiency of zinc carriers on growth and zinc nutrition of corn

International Nuclear Information System (INIS)

Prasad, B.; Sinha, K.

1981-01-01

A comparison of different zinc carriers showed that application of Zn-DTPA, Zn-EDTA, Zn-fulvate and ZnSO 4 significantly increased the dry matter yield and zinc uptake by corn over the control treatment where no zinc was applied. The chelates in particular enhanced to a greater extent the uptake of both native and applied sources than that observed with ZnSO 4 as the zinc carrier. Both the dry matter yield and zinc uptake by corn showed a positive and significant relationship with self-diffusion coefficient of zinc showing thereby that diffusion contributed mainly the supply of Zn from the ambient soil matrix to plant roots. The effectiveness of the chelates varied depending on their capacity to retain Zn in a soluble form in the soil solution. It is evident that zinc nutrition of plants in alkaline and calcareous soils can be more effectively regulated by both synthetic and natural chelates or organic manures which contain substantial amount of complexed zinc. (orig.)

Preconcentration and Determination of Copper and Zinc in Natural Water Samples by ICP-AES After Complexation and Sorption on Amberlite XAD-2

Directory of Open Access Journals (Sweden)

Ferreira Sérgio Luis Costa

1998-01-01

Full Text Available The present paper describes a procedure for separation, preconcentration and sequential determination of trace amounts of copper and zinc in natural water samples, by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES. The proposed method is based on the complexation of copper(II and zinc(II ions by 1-(2-thiazolylazo-2-naphthol (TAN and sorption on to Amberlite XAD-2 resin. Parameters such as: TAN amount, pH effect on the complexation and sorption of TAN complexes, agitation time for complete sorption, concentration of metal ion, mass of Amberlite XAD-2, desorption of metal ions from XAD-2 resin and sample volume were studied. The results demonstrated that the copper(II and zinc(II ions, in the range of 0.10 to 100.00 mug, contained in a solution sample volume of 400 mL, in the pH range of 5.7 to 8.3, on the form of TAN complexes had been quantitatively retained on to XAD-2 resin. The shaking time required for sorption is 1 h using a resin mass of 1.4 g. The solution for determination of copper and zinc by ICP-AES is obtained, after desorption of the ions from the XAD-2 resin, using 5 mL of 2 mol L-1 hydrochloric acid and shaking the system for 5 min. The procedure was applied to the determination of copper and zinc in several natural water samples. The standard addition technique was applied and the obtained recoveries revealed that the proposed procedure has a good accuracy. A high enrichment factor (80 and simplicity are the main advantages in this analytical protocol.

Availability of native and fertilizer zinc in some Indian soils: studies with 65Zinc

International Nuclear Information System (INIS)

Chaudhury, J.; Deb, D.L.

1979-01-01

Isotopically exchangeable zinc (Et values) was determined by different methods in some soils having pH(H 2 O) varying from 3.05 to 8.40 using 65 Zn. The Et values obtained using different extractants showed significant correlation with available zinc, organic carbon and soil pH. The recovery of applied zinc in the aqueous phase was less than one percent in most of the soils having pH higher than 7.0. Application of zinc with complexing agents like DTPA and EDTA increased the recovery of applied zinc in the solution to about 95 percent. Soil pH, organic C and DTPA extractable zinc showed significant relationship with the recovery of applied zinc under different treatments. Use of EDTA and DTPA extractants reduced the zinc buffering capacity of soil to a value less than one, irrespective of the initial pH of the soil, whereas the values were comparatively higher in presence of different levels of zinc carrier. (auth.)

Surface compounds and the routes of formation of the reaction products in the interaction of propylene with zinc oxide

Energy Technology Data Exchange (ETDEWEB)

Davydov, A.A.; Yefremov, A.A.; Mikhalchenko, V.G.; Sokolovskii, V.D.

1979-06-15

Temperature programed desorption of propylene and allyl bromide from zinc oxide in the absence and presence of oxygen and an IR spectroscopic study of the adsorbed allyl bromide showed that propylene chemisorbed reversibly as a m-allyl species which may undergo dimerization at higher pressures or temperatures but does not form acrolein because the necessary electron transfer does not proceed on the n-type zinc oxide; that propylene also forms carbon dioxide and water via carbonate/carboxylate intermediates; and that the allyl bromide, which forms cations on the zinc oxide surface, is oxidized to acrolein.

A bipyridine-ligated zinc(II) complex with bridging flavonolate ligation: synthesis, characterization, and visible-light-induced CO release reactivity.

Science.gov (United States)

Sorenson, Shayne; Popova, Marina; Arif, Atta M; Berreau, Lisa M

2017-09-01

Metal-flavonolate compounds are of significant current interest as synthetic models for quercetinase enzymes and as bioactive compounds of importance to human health. Zinc-3-hydroxyflavonolate compounds, including those of quercetin, kampferol, and morin, generally exhibit bidentate coordination to a single Zn II center. The bipyridine-ligated zinc-flavonolate compound reported herein, namely bis(μ-4-oxo-2-phenyl-4H-chromen-3-olato)-κ 3 O 3 :O 3 ,O 4 ;κ 3 O 3 ,O 4 :O 3 -bis[(2,2'-bipyridine-κ 2 N,N')zinc(II)] bis(perchlorate), {[Zn 2 (C 15 H 9 O 3 ) 2 (C 10 H 8 N 2 ) 2 ](ClO 4 ) 2 } n , (1), provides an unusual example of bridging 3-hydroxyflavonolate ligation in a dinuclear metal complex. The symmetry-related Zn II centers of (1) exhibit a distorted octahedral geometry, with weak coordination of a perchlorate anion trans to the bridging deprotonated O atom of the flavonolate ligand. Variable-concentration conductivity measurements provide evidence that, when (1) is dissolved in CH 3 CN, the complex dissociates into monomers. 1 H NMR resonances for (1) dissolved in d 6 -DMSO were assigned via HMQC to the H atoms of the flavonolate and bipyridine ligands. In CH 3 CN, (1) undergoes quantitative visible-light-induced CO release with a quantum yield [0.004 (1)] similar to that exhibited by other mononuclear zinc-3-hydroxyflavonolate complexes. Mass spectroscopic identification of the [(bpy) 2 Zn(O-benzoylsalicylate)] + ion provides evidence of CO release from the flavonol and of ligand exchange at the Zn II center.

Synthesis and crystal structure of a polymeric zinc(II complex derived from 4-nitro- phenylacetic acid and propane-1,3-diamine

Directory of Open Access Journals (Sweden)

G-H. Sheng

2014-05-01

Full Text Available A new polymeric zinc(II complex, [ZnL2(PDA]n, has been prepared by the reaction of zinc sulfate, 4-nitrophenylacetic acid, and propane-1,3-diamine (PDA in water. Structure of the complex has been characterized by single-crystal X-ray diffraction. The complex crystallizes as orthorhombic space group Pnma, with unit cell dimensions a = 15.732(1 Å, b = 23.912(1 Å, c = 5.5565(3 Å, V = 2090.2(2 Å3, Z = 4, R1 = 0.0427, wR2 = 0.0968, S = 1.048. The Zn atom is coordinated in a tetrahedral geometry. Single crystals of the complex are stabilized by hydrogen bonds and p···p interactions. DOI: http://dx.doi.org/10.4314/bcse.v28i2.17

Mononuclear zinc(II) complexes of 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols: Synthesis, structural characterization, DNA binding and cheminuclease activities

Science.gov (United States)

Ravichandran, J.; Gurumoorthy, P.; Karthick, C.; Kalilur Rahiman, A.

2014-03-01

Four new zinc(II) complexes [Zn(HL1-4)Cl2] (1-4), where HL1-4 = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, have been isolated and fully characterized using various spectro-analytical techniques. The X-ray crystal structure of complex 4 shows the distorted trigonal-bipyramidal coordination geometry around zinc(II) ion. The crystal packing is stabilized by intermolecular NH⋯O hydrogen bonding interaction. The complexes display no d-d electronic band in the visible region due to d10 electronic configuration of zinc(II) ion. The electrochemical properties of the synthesized ligands and their complexes exhibit similar voltammogram at reduction potential due to electrochemically innocent Zn(II) ion, which evidenced that the electron transfer is due to the nature of the ligand. Binding interaction of complexes with calf thymus DNA was studied by UV-Vis absorption titration, viscometric titration and cyclic voltammetry. All complexes bind with CT DNA by intercalation, giving the binding affinity in the order of 2 > 1 ≫ 3 > 4. The prominent cheminuclease activity of complexes on plasmid DNA (pBR322 DNA) was observed in the absence and presence of H2O2. Oxidative pathway reveals that the underlying mechanism involves hydroxyl radical.

Nonlinear absorption dynamics using field-induced surface hopping: zinc porphyrin in water.

Science.gov (United States)

Röhr, Merle I S; Petersen, Jens; Wohlgemuth, Matthias; Bonačić-Koutecký, Vlasta; Mitrić, Roland

2013-05-10

We wish to present the application of our field-induced surface-hopping (FISH) method to simulate nonlinear absorption dynamics induced by strong nonresonant laser fields. We provide a systematic comparison of the FISH approach with exact quantum dynamics simulations on a multistate model system and demonstrate that FISH allows for accurate simulations of nonlinear excitation processes including multiphoton electronic transitions. In particular, two different approaches for simulating two-photon transitions are compared. The first approach is essentially exact and involves the solution of the time-dependent Schrödinger equation in an extended manifold of excited states, while in the second one only transiently populated nonessential states are replaced by an effective quadratic coupling term, and dynamics is performed in a considerably smaller manifold of states. We illustrate the applicability of our method to complex molecular systems by simulating the linear and nonlinear laser-driven dynamics in zinc (Zn) porphyrin in the gas phase and in water. For this purpose, the FISH approach is connected with the quantum mechanical-molecular mechanical approach (QM/MM) which is generally applicable to large classes of complex systems. Our findings that multiphoton absorption and dynamics increase the population of higher excited states of Zn porphyrin in the nonlinear regime, in particular in solution, provides a means for manipulating excited-state properties, such as transient absorption dynamics and electronic relaxation. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An index of floodplain surface complexity

Science.gov (United States)

Scown, Murray W.; Thoms, Martin C.; DeJager, Nathan R.

2016-01-01

Floodplain surface topography is an important component of floodplain ecosystems. It is the primary physical template upon which ecosystem processes are acted out, and complexity in this template can contribute to the high biodiversity and productivity of floodplain ecosystems. There has been a limited appreciation of floodplain surface complexity because of the traditional focus on temporal variability in floodplains as well as limitations to quantifying spatial complexity. An index of floodplain surface complexity (FSC) is developed in this paper and applied to eight floodplains from different geographic settings. The index is based on two key indicators of complexity, variability in surface geometry (VSG) and the spatial organisation of surface conditions (SPO), and was determined at three sampling scales. FSC, VSG, and SPO varied between the eight floodplains and these differences depended upon sampling scale. Relationships between these measures of spatial complexity and seven geomorphological and hydrological drivers were investigated. There was a significant decline in all complexity measures with increasing floodplain width, which was explained by either a power, logarithmic, or exponential function. There was an initial rapid decline in surface complexity as floodplain width increased from 1.5 to 5 km, followed by little change in floodplains wider than 10 km. VSG also increased significantly with increasing sediment yield. No significant relationships were determined between any of the four hydrological variables and floodplain surface complexity.

The stability and half-metallicity of (001) surface and (001) interface based on zinc blende MnAs

Science.gov (United States)

Han, Hongpei; Feng, Tuanhui; Zhang, Chunli; Feng, Zhibo; Li, Ming; Yao, K. L.

2018-06-01

Motivated by the growth of MnAs/GaAs thin films in many experimental researches, we investigate the electronic and magnetic properties of bulk, (001) surfaces and (001) interfaces for zinc blende MnAs by means of first-principle calculations. It is confirmed that zinc blende MnAs is a nearly half-metallic ferromagnet with 4.00 μB magnetic moment. The calculated density of states show that the half-metallicity exists in As-terminated (001) surface while it is lost in Mn-terminated (001) surface. For the (001) interfaces of MnAs with semiconductor GaAs, it is found that As-Ga and Mn-As interfaces not only have higher spin polarization but also are more stable among the four considered interfaces. Our results would be helpful to grow stable and high polarized thin films or multilayers for the practical applications of spintronic devices.

Various ways to reduce zinc oxide levels in S-SBR rubber compounds

NARCIS (Netherlands)

Heideman, G.; Noordermeer, Jacobus W.M.; Datta, Rabin; van Baarle, Ben

2007-01-01

Because of environmental concerns, the zinc content in rubber compounds has come under scrutiny. The research described in this article encompasses zinc-oxide, various zinc-complexes and alternative metal oxides as activators for sulphur vulcanisation. Regarding zinc complexes, it can be concluded

Synthesis, characterization and anticancer activity of kaempferol-zinc(II) complex.

Science.gov (United States)

Tu, Lv-Ying; Pi, Jiang; Jin, Hua; Cai, Ji-Ye; Deng, Sui-Ping

2016-06-01

According to the previous studies, the anticancer activity of flavonoids could be enhanced when they are coordinated with transition metal ions. In this work, kaempferol-zinc(II) complex (kaempferol-Zn) was synthesized and its chemical properties were characterized by UV-VIS, FT-IR, (1)H NMR, elemental analysis, electrospray mass spectrometry (ES-MS) and fluorescence spectroscopy, which showed that the synthesized complex was coordinated with a Zn(II) ion via the 3-OH and 4-oxo groups. The anticancer effects of kaempferol-Zn and free kaempferol on human oesophageal cancer cell line (EC9706) were compared. MTT results demonstrated that the killing effect of kaempferol-Zn was two times higher than that of free kaempferol. Atomic force microscopy (AFM) showed the morphological and ultrastructural changes of cellular membrane induced by kaempferol-Zn at subcellular or nanometer level. Moreover, flow cytometric analysis indicated that kaempferol-Zn could induce apoptosis in EC9706 cells by regulating intracellular calcium ions. Collectively, all the data showed that kaempferol-Zn might be served as a kind of potential anticancer agent. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluación de la dimensión fractal reactiva de los glicinatos de magnesio, manganeso y zinc Evaluation of the reactive fractal dimension of magnesium, manganese and zinc glycinates

Directory of Open Access Journals (Sweden)

Julie Fernanda Benavides Arevalo

2012-03-01

. The latter was related to the water dissolution process in order to obtain two associated properties, that is, the surface fractal dimension and the reactive fractal dimension, Conclusions: these results showed that the dissolution of glycinates occurs through the pores or cracks found in their particle surfaces and that these complexes are suitable for use in nutritional formulations as sources of magnesium, manganese and zinc.

Synthesis and characterization of an effective organic/inorganic hybrid green corrosion inhibitive complex based on zinc acetate/Urtica Dioica

Science.gov (United States)

Salehi, E.; Naderi, Reza; Ramezanzadeh, B.

2017-02-01

This study aims at synthesis and characterization of an effective corrosion inhibitive complex based on zinc acetate/Urtica Dioica (ZnA-U.D) for corrosion protection of mild steel in chloride solution. The chemical structure and morphology of the complex were characterized by Fourier transform infrared spectroscopy (FT-IR), UV-vis, thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The corrosion protection performance of the mild steel samples dipped in 3.5 wt.% NaCl solutions with and without ZnA-U.D extract was investigated by visual observations, open circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS) and polarization test. Results revealed that the ZnA successfully chelated with organic inhibitive compounds (i.e Quercetin, Quinic acid, Caffeic acid, Hystamine and Serotonin) present in the U.D extract. The electrochemical measurements revealed the effective inhibition action of ZnA-U.D complex in the sodium chloride solution on the mild steel. The synergistic effect between Zn2+ and organic compounds present in the U.D extract resulted in protective film deposition on the steel surface, which was proved by SEM and XPS analyses.

Machining of Complex Sculptured Surfaces

CERN Document Server

2012-01-01

The machining of complex sculptured surfaces is a global technological topic in modern manufacturing with relevance in both industrialized and emerging in countries particularly within the moulds and dies sector whose applications include highly technological industries such as the automotive and aircraft industry. Machining of Complex Sculptured Surfaces considers new approaches to the manufacture of moulds and dies within these industries. The traditional technology employed in the manufacture of moulds and dies combined conventional milling and electro-discharge machining (EDM) but this has been replaced with  high-speed milling (HSM) which has been applied in roughing, semi-finishing and finishing of moulds and dies with great success. Machining of Complex Sculptured Surfaces provides recent information on machining of complex sculptured surfaces including modern CAM systems and process planning for three and five axis machining as well as explanations of the advantages of HSM over traditional methods ra...

The study and microstructure analysis of zinc and zinc oxide

Directory of Open Access Journals (Sweden)

N. Luptáková

2015-01-01

Full Text Available The given paper is closely connected with the process of the manufacturing of ZnO. The purity of the metal zinc has crucial influence on the quality of ZnO. ZnO can be produced by pyrometallurgical combustion of zinc and hard zinc. But this mentioned method of preparation leads to the creation of the enormous amount of waste including chemical complexes. On the basis of the occurrence of the residual content of other elements, it is possible to make prediction about the material behavior in the metallographic process. The input and finally materials were investigated and this investigation was done from the aspect of structural and chemical composition of the materials.

Removal of arsenate by ferrihydrite via surface complexation and surface precipitation

Energy Technology Data Exchange (ETDEWEB)

Jiang, Xiuli [Department of Environment Engineering, College of the Environment and Ecology, and The Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, Xiamen University, Xiamen (China); Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, and The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen (China); Peng, Changjun; Fu, Dun; Chen, Zheng [Department of Environment Engineering, College of the Environment and Ecology, and The Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, Xiamen University, Xiamen (China); Shen, Liang [Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, and The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen (China); Li, Qingbiao [Department of Environment Engineering, College of the Environment and Ecology, and The Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, Xiamen University, Xiamen (China); Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, and The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen (China); Ouyang, Tong, E-mail: yz3t@xmu.edu.cn [Department of Environment Engineering, College of the Environment and Ecology, and The Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, Xiamen University, Xiamen (China); Wang, Yuanpeng, E-mail: wypp@xmu.edu.cn [Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, and The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen (China)

2015-10-30

Graphical abstract: - Highlights: • Surface complexation and surface precipitation of As on ferrihydrite happen at pH 3–6. • The formation of surface precipitation enhanced As(V) adsorption. • The dissolved Fe{sup 3+} had a good linear relationship with the amount of arsenate re-adsorption. - Abstract: In this study, macroscopic and spectroscopic experimental methods accurately modeled the sorption process of arsenate on ferrihydrite. EXAFS, X-ray diffraction and infrared (IR) spectroscopy indicated that the behavior of As(V) adsorption onto ferrihydrite took place mainly via surface complexation and surface precipitation at acidic pH (3.0–6.0), while the surface precipitation was dominated at longer time intervals and higher Fe{sup 3+} concentration. The macroscopic competitive adsorption experiment between arsenate with phosphate indicated two types of adsorption sites existing on the surface of ferrihydrite, i.e., non-exchangeable sites, which are responsible for a rapid surface complex formation; and exchangeable sites for a slow build-up of surface precipitates. In the slow build-up precipitates, the As(V) surface coverage (mmol/g) exhibited a good linear relationship (R{sup 2} = 0.952) with the amount of dissolved Fe{sup 3+}. Three steps are involved during the process of surface precipitation, i.e., (1) an initial uptake of As(V) via surface complexation; (2) re-adsorption of Fe{sup 3+} leaching from ferrihydrite on the surface complex; and (3) As(V) adsorption via surface complexation again and finally forming the surface precipitate.

Predictive Surface Complexation Modeling

Energy Technology Data Exchange (ETDEWEB)

Sverjensky, Dimitri A. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Earth and Planetary Sciences

2016-11-29

Surface complexation plays an important role in the equilibria and kinetics of processes controlling the compositions of soilwaters and groundwaters, the fate of contaminants in groundwaters, and the subsurface storage of CO₂ and nuclear waste. Over the last several decades, many dozens of individual experimental studies have addressed aspects of surface complexation that have contributed to an increased understanding of its role in natural systems. However, there has been no previous attempt to develop a model of surface complexation that can be used to link all the experimental studies in order to place them on a predictive basis. Overall, my research has successfully integrated the results of the work of many experimentalists published over several decades. For the first time in studies of the geochemistry of the mineral-water interface, a practical predictive capability for modeling has become available. The predictive correlations developed in my research now enable extrapolations of experimental studies to provide estimates of surface chemistry for systems not yet studied experimentally and for natural and anthropogenically perturbed systems.

An in situ study of zirconium-based conversion treatment on zinc surfaces

Energy Technology Data Exchange (ETDEWEB)

Taheri, P. [Materials innovation institute (M2i), Elektronicaweg 25, 2628 XG Delft (Netherlands); Delft University of Technology, Department of Materials Science and Engineering, Mekelweg 2, 2628 CD Delft (Netherlands); Laha, P. [Vrije Universiteit Brussel, Department of Electrochemical and Surface Engineering, Pleinlaan 2, B-1050 Brussels (Belgium); Terryn, H. [Delft University of Technology, Department of Materials Science and Engineering, Mekelweg 2, 2628 CD Delft (Netherlands); Vrije Universiteit Brussel, Department of Electrochemical and Surface Engineering, Pleinlaan 2, B-1050 Brussels (Belgium); Mol, J.M.C., E-mail: J.M.C.Mol@tudelft.nl [Delft University of Technology, Department of Materials Science and Engineering, Mekelweg 2, 2628 CD Delft (Netherlands)

2015-11-30

Highlights: • We investigated the deposition mechanism of zirconium conversion layer on zinc. • In situ FTIR and electrochemical measurements are conducted. • The initial hydroxyl fraction plays an important role in the deposition process. • Deposition starts with hydroxyl removal by fluoride ions. • An increase of alkalinity adjacent to the surface promotes deposition of Zr. - Abstract: This study is focused on the deposition process of zirconium-based conversion layers on Zn surfaces. The analysis approach is based on a Kretschmann configuration in which in situ ATR-FTIR spectroscopy is combined with open circuit potential (OCP) and near surface pH measurements. Differently pretreated Zn surfaces were subjected to conversion treatments, while the Zr-based deposition mechanism was probed in situ. It was found that the initial hydroxyl fraction promotes the overall Zr conversion process as the near surface pH values are influenced by the initial hydroxyl fraction. Kinetics of the early surface activation and the subsequent Zr-based conversion process are discussed and correlated to the initial hydroxyl fractions.

Surface functionalization of carbon nanofibers by sol-gel coating of zinc oxide

Energy Technology Data Exchange (ETDEWEB)

Shao Dongfeng [Key Laboratory of Eco-textiles, Ministry of Education, Jiangnan University, Wuxi 214122 (China); Changzhou Textile Garment Institute, Changzhou 213164 (China); Wei Qufu [Key Laboratory of Eco-textiles, Ministry of Education, Jiangnan University, Wuxi 214122 (China)], E-mail: qfwei@jiangnan.edu.cn; Zhang Liwei; Cai Yibing; Jiang Shudong [Key Laboratory of Eco-textiles, Ministry of Education, Jiangnan University, Wuxi 214122 (China)

2008-08-15

In this paper the functional carbon nanofibers were prepared by the carbonization of ZnO coated PAN nanofibers to expand the potential applications of carbon nanofibers. Polyacrylonitrile (PAN) nanofibers were obtained by electrospinning. The electrospun PAN nanofibers were then used as substrates for depositing the functional layer of zinc oxide (ZnO) on the PAN nanofiber surfaces by sol-gel technique. The effects of coating, pre-oxidation and carbonization on the surface morphology and structures of the nanofibers were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Scanning electron microscopy (SEM), respectively. The results of SEM showed a significant increase of the size of ZnO nanograins on the surface of nanofibers after the treatments of coating, pre-oxidation and carbonization. The observations by SEM also revealed that ZnO nanoclusters were firmly and clearly distributed on the surface of the carbon nanofibers. FTIR examination also confirmed the deposition of ZnO on the surface of carbon nanofibers. The XRD analysis indicated that the crystal structure of ZnO nanograins on the surface of carbon nanofibers.

Zinc(II) halide complexes with 2-methoxyaniline ligand: Synthesis, characterization, thermal analyses, crystal structure determination and luminescent properties

Science.gov (United States)

Amani, Vahid

2018-03-01

Three new mononuclear zinc(II) complexes, [Zn(2-MeO-C6H4NH2)2X2] (X is Cl in 1, Br in 2 and I in 3), were prepared from the reactions of ZnX2 with 2-methoxyaniline (2-MeO-C6H4NH2) ligand in methanol. Suitable crystals of these complexes were obtained for X-ray diffraction measurements by slow evaporation of methanol solution at room temperature. The three complexes were thoroughly characterized by thermogravimetric analysis, elemental analysis (CHNO), spectral methods (IR, UV-Vis, 13C{1H}NMR, 1H NMR and luminescence), and single crystal X-ray diffraction. The X-ray structural analysis indicated that in the structures of these complexes, the zinc(II) cation is four-coordinated in a distorted tetrahedral configuration by two N atoms from two 2-methoxyanyline ligands and two halide anions. Also, in these complexes intermolecular interactions, for example Nsbnd H⋯X hydrogen bonds (in 1-3), Csbnd H⋯X hydrogen bonds (in 3), Csbnd H⋯π interactions (in 1 and 2) and π⋯π interactions (in 3), are effective in the stabilization of the crystal structures. In addition, the luminescence spectra of all complexes in methanolic solution show that the intensity of their emission bands is stronger than that for free 2-methoxyaniline ligand.

Improved corrosion behavior of nanocrystalline zinc produced by pulse-current electrodeposition

International Nuclear Information System (INIS)

Youssef, Kh.M.S.; Koch, C.C.; Fedkiw, P.S.

2004-01-01

Pulse electrodeposition was used to produce nanocrystalline (nc) zinc from zinc chloride electrolyte with polyacrylamide and thiourea as additives. Field emission scanning electron microscopy (FESEM) was used to study the grain size and surface morphology of the deposits and X-ray diffraction was used to examine their preferred orientation. Corrosion behavior of the electrodeposited nc zinc in comparison with electrogalvanized (EG) steel in de-aerated 0.5 N NaOH solution was studied using potentiodynamic polarization and impedance measurements. A scanning electron microscope (SEM) was used to characterize the surface morphology of the EG steel before corrosion testing. Surface morphologies of nc zinc deposits and EG steel were also studied after potentiondynamic polarization by SEM. Nanocrystalline zinc (56 nm) with random orientation was produced. The estimated corrosion rate of nc zinc was found to be about 60% lower than that of EG steel, 90 and 229 μA/cm 2 , respectively. The surface morphology of corroded nc zinc was characterized by discrete etch pits, however, uniform corrosion was obtained after potentiodynamic polarization of EG steel. The passive film formed on the nc zinc surface seems to be a dominating factor for the corrosion behavior observed

In silico, in vitro and antifungal activity of the surface layers formed on zinc during this biomaterial degradation

Science.gov (United States)

Alves, Marta M.; Marques, Luísa M.; Nogueira, Isabel; Santos, Catarina F.; Salazar, Sara B.; Eugénio, Sónia; Mira, Nuno P.; Montemor, M. F.

2018-07-01

Zinc (Zn) has been proposed as an alternative metallic biodegradable material to support transient wound-healing processes. Once a Zn piece is implanted inside the organism the degradation will depend upon the physiological surrounding environment. This, by modulating the composition of the surface layers formed on Zn devices, will govern the subsequent interactions with the surrounding living cells (e.g. biocompatibility and/or antifungal behaviour). In silico simulation of an implanted Zn piece at bone-muscle interface or inside the bone yielded the preferential precipitation of simonkolleite or zincite, respectively. To study the impact of these surface layers in the in vitro behaviour of Zn biomaterials, simonkolleite and zincite where synthesised. The successful production of simonkolleite or zincite was confirmed by an extensive physicochemical characterization. An in vitro layer formed on the top of these surface layers revealed that simonkolleite was rather inert, while zincite yielded a complex matrix containing hydroxyapatite, an important bone analogue. When analysing the "anti-biofilm" activity simonkolleite stood out for its activity against an important pathogenic fungi involved in implant-device infections, Candida albicans. The possible physiological implications of these findings are discussed.

Complexes cobalt(II, zinc(II and copper(II with some newly synthesized benzimidazole derivatives and their antibacterial activity

Directory of Open Access Journals (Sweden)

S. O. PODUNAVAC-KUZMANOVIC

1999-05-01

Full Text Available The preparation and properties of some complexes of cobalt(II, zinc(II and copper(II with several newly synthesized benzimidazole derivatives (L are reported. The complexes, of the general formula [MCl2L2] (M=Co(II, Zn(II and [CuCl2L(H2O], have a tetrahedral structure. The complexes were characterized by elemental analysis, molar conductivity, magnetic susceptibility measurements, IR and absorption electronic spectra. The antibacterial activitiy of the benzimidazoles and their complexes was evaluated against Erwinia carotovora subsp. carotovora and Erwinia amylovora. The complexes were found to be more toxic than the ligands.

(Pyridine)(tetrahydroborato)zinc complex, (Zn(BH4)2(py)), as a new stable, efficient and chemoselective reducing agent for reduction of carbonyl compounds

International Nuclear Information System (INIS)

Zeynizadeh, Behzad; Faraji, Fariba

2003-01-01

(Pyridine)(tetrahydroborato)zinc complex, (Zn(BH 4 ) 2 (py)), as a stable white solid, was prepared quantitatively by complexation of an equimolar amount of zinc tetrahydroborate and pyridine at room temperature. This reagent can easily reduce variety of carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones and α,β-unsaturated carbonyl compounds to their corresponding alcohols in good to excellent yields. Reduction reactions were performed in ether or THF at room temperature or under reflux conditions. In addition, the chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing agent

Surface investigation and tribological mechanism of a sulfate-based lubricant deposited on zinc-coated steel sheets

Energy Technology Data Exchange (ETDEWEB)

Timma, Christian, E-mail: christian.timma@thyssenkrupp.com [ThyssenKrupp Steel Europe AG, Technology & Innovation, Kaiser-Wilhelm Str. 100, 47166 Duisburg (Germany); University of Duisburg-Essen, Faculty of Chemistry, CENIDE, Universitätsstraße 7, 45141 Essen (Germany); Lostak, Thomas; Janssen, Stella; Flock, Jörg [ThyssenKrupp Steel Europe AG, Technology & Innovation, Kaiser-Wilhelm Str. 100, 47166 Duisburg (Germany); Mayer, Christian [University of Duisburg-Essen, Faculty of Chemistry, CENIDE, Universitätsstraße 7, 45141 Essen (Germany)

2016-12-30

Highlights: • Skin-passed hot-dip galvanized (HDG-) steel sheets were coated with (NH{sub 4}){sub 2}SO{sub 4} in a common roll-coating method. • A formation of (NH{sub 4}){sub 2}Zn(SO{sub 4}) * xH{sub 2}O was observed and the reaction mainly occurred in the skin-passed areas of the surface. • Sulfate coated samples reveal a superior friction behaviour in oil-like conditions compared non-sulfated specimen. - Abstract: Phosphatation is a well-known technique to improve friction and wear behaviour of zinc coated steel, but has a variety of economic and ecologic limitations. In this study an alternative coating based on ammonium sulfate ((NH{sub 4}){sub 2}SO{sub 4}) is applied on skin-passed hot-dip galvanized steel sheets in order to investigate its surface chemical and tribological behaviour in a Pin-on-Disk Tribometer. Raman- and X-ray photoelectron spectroscopic results revealed a formation of ammonium zinc sulfate ((NH{sub 4}){sub 2}Zn(SO{sub 4}){sub 2} * xH{sub 2}O) on the surface, which is primarily located in the skin-passed areas of the steel material. Sulfate coated samples exhibited a superior friction behaviour in Pin-on-Disk Tests using squalane as a model substance for oil-like lubricated conditions and a formation of a thin lubrication film is obtained in the wear track. Squalane acts as a carrier substance for ammonium zinc sulfate, leading to an effective lubrication film in the wear track.

Zinc hexacyanoferrate film as an effective protecting layer in two-step and one-step electropolymerization of pyrrole on zinc substrate

Energy Technology Data Exchange (ETDEWEB)

Pournaghi-Azar, M.H. [Electroanalytical Chemistry Laboratory, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of)]. E-mail: pournaghiazar@tabrizu.ac.ir; Nahalparvari, H. [Electroanalytical Chemistry Laboratory, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of)

2005-03-15

The two-step and one-step electrosynthesis processes of polypyrrole (PPy) films on the zinc substrate are described. The two-step process includes (i) the zinc surface pretreatment with hexacyanoferrate ion in the aqueous medium in order to form a zinc hexacyanoferrate (ZnHCF) film non-blocking passive layer on the surface and with the view to prevent its reactivity and (ii) electropolymerization of pyrrole on the ZnHCF vertical bar Zn-modified electrode in aqueous pyrrole solution. In this context, both the non-electrolytic and electrolytic procedures were adapted, and the effect of some experimental conditions such as supporting electrolyte, pH and temperature of the solution at the zinc surface pretreatment step as well as pyrrole concentration and electrochemical techniques at the polymerization step was investigated. By optimizing the experimental conditions in both steps, we have obtained a homogeneous and strongly adherent PPy films on the zinc substrate. The one-step process is based on the use of an aqueous medium containing Fe(CN){sub 6}{sup 4-} and pyrrole. The ferrocyanide ion passivates the substrate by formation of ZnHCF film during the electropolymerization process of pyrrole and therefore makes it possible to obtain strongly adherent PPy films, with controlled thickness, either by cyclic voltammetry or by electrolysis at constant current or constant potential without any previously treatment of the zinc electrode surface. The polypyrrole films deposited on the zinc electrode were characterized by cyclic voltammetry and scanning electron microscopic (SEM) measurement.

Zinc hexacyanoferrate film as an effective protecting layer in two-step and one-step electropolymerization of pyrrole on zinc substrate

International Nuclear Information System (INIS)

Pournaghi-Azar, M.H.; Nahalparvari, H.

2005-01-01

The two-step and one-step electrosynthesis processes of polypyrrole (PPy) films on the zinc substrate are described. The two-step process includes (i) the zinc surface pretreatment with hexacyanoferrate ion in the aqueous medium in order to form a zinc hexacyanoferrate (ZnHCF) film non-blocking passive layer on the surface and with the view to prevent its reactivity and (ii) electropolymerization of pyrrole on the ZnHCF vertical bar Zn-modified electrode in aqueous pyrrole solution. In this context, both the non-electrolytic and electrolytic procedures were adapted, and the effect of some experimental conditions such as supporting electrolyte, pH and temperature of the solution at the zinc surface pretreatment step as well as pyrrole concentration and electrochemical techniques at the polymerization step was investigated. By optimizing the experimental conditions in both steps, we have obtained a homogeneous and strongly adherent PPy films on the zinc substrate. The one-step process is based on the use of an aqueous medium containing Fe(CN) 6 4- and pyrrole. The ferrocyanide ion passivates the substrate by formation of ZnHCF film during the electropolymerization process of pyrrole and therefore makes it possible to obtain strongly adherent PPy films, with controlled thickness, either by cyclic voltammetry or by electrolysis at constant current or constant potential without any previously treatment of the zinc electrode surface. The polypyrrole films deposited on the zinc electrode were characterized by cyclic voltammetry and scanning electron microscopic (SEM) measurement

Activity incorporation into zinc doped PWR oxides

International Nuclear Information System (INIS)

Maekelae, Kari

1998-01-01

Activity incorporation into the oxide layers of PWR primary circuit constructional materials has been studied in Halden since 1993. The first zinc injection tests showed that zinc addition resulted in thinner oxide layers on new metal surfaces and reduced further incorporation of activity into already existing oxides. These tests were continued to find out the effects of previous zinc additions on the pickup of activity onto the surface oxides which were subsequently exposed to zinc-free coolant. The results showed that previous zinc addition will continue to reduce the rate of Co-60 build-up on out-of-core surfaces in subsequent exposure to zinc-free coolants. However, the previous Zn free test was performed for a relatively short period of time and the water chemistry programme was continued to find out the long term effects for extended periods without zinc. The activity incorporation into the stainless steel oxides started to increase as soon as zinc dosing to the coolant was stopped. The Co-60 concentration was lowest on all of the coupons which were first oxidised in Zn containing primary coolant. After the zinc injection period the thickness of the oxides increased, but activity in the oxide films did not increase at the same rate. This could indicate that zinc in the oxide blocks the adsorption sites for Co-60 incorporation. The Co-60 incorporation rate into the oxides on Inconel 600 seemed to be linear whether the oxide was pre-oxidised with or without Zn. The results indicate that zinc can either replace or prevent cobalt transport in the oxides. The results show that for zinc injection to be effective it should be carried out continuously. Furthermore the actual mechanism by which Zn inhibits the activity incorporation into the oxides is still not clear. Therefore, additional work has to follow with specified materials to verify the conclusions drawn in this work. (author)

Luminescent zinc(ii) and copper(i) complexes for high-performance solution-processed monochromic and white organic light-emitting devices.

Science.gov (United States)

Cheng, Gang; So, Gary Kwok-Ming; To, Wai-Pong; Chen, Yong; Kwok, Chi-Chung; Ma, Chensheng; Guan, Xiangguo; Chang, Xiaoyong; Kwok, Wai-Ming; Che, Chi-Ming

2015-08-01

The synthesis and spectroscopic properties of luminescent tetranuclear zinc(ii) complexes of substituted 7-azaindoles and a series of luminescent copper(i) complexes containing 7,8-bis(diphenylphosphino)-7,8-dicarba- nido -undecaborate ligand are described. These complexes are stable towards air and moisture. Thin film samples of the luminescent copper(i) complexes in 2,6-dicarbazolo-1,5-pyridine and zinc(ii) complexes in poly(methyl methacrylate) showed emission quantum yields of up to 0.60 (for Cu-3 ) and 0.96 (for Zn-1 ), respectively. Their photophysical properties were examined by ultrafast time-resolved emission spectroscopy, temperature dependent emission lifetime measurements and density functional theory calculations. Monochromic blue and orange solution-processed OLEDs with these Zn(ii) and Cu(i) complexes as light-emitting dopants have been fabricated, respectively. Maximum external quantum efficiency (EQE) of 5.55% and Commission Internationale de l'Eclairage (CIE) coordinates of (0.16, 0.19) were accomplished with the optimized Zn-1 -OLED while these values were, respectively 15.64% and (0.48, 0.51) for the optimized Cu-3 -OLED. Solution-processed white OLEDs having maximum EQE of 6.88%, CIE coordinates of (0.42, 0.44), and colour rendering index of 81 were fabricated by using these luminescent Zn(ii) and Cu(i) complexes as blue and orange light-emitting dopant materials, respectively.

Zinc Bioavailability from Phytate-Rich Foods and Zinc Supplements. Modeling the Effects of Food Components with Oxygen, Nitrogen, and Sulfur Donor Ligands.

Science.gov (United States)

Tang, Ning; Skibsted, Leif H

2017-10-04

Aqueous solubility of zinc phytate (K sp = (2.6 ± 0.2) × 10 -47 mol 7 /L 7 ), essential for zinc bioavailability from plant foods, was found to decrease with increasing temperature corresponding to ΔH dis of -301 ± 22 kJ/mol and ΔS dis of -1901 ± 72 J/(mol K). Binding of zinc to phytate was found to be exothermic for the stronger binding site and endothermic for the weaker binding site. The solubility of the slightly soluble zinc citrate and insoluble zinc phytate was found to be considerably enhanced by the food components with oxygen donor, nitrogen donor, and sulfur donor ligands. The driving force for the enhanced solubility is mainly due to the complex formation between zinc and the investigated food components rather than ligand exchange and ternary complex formation as revealed by quantum mechanical calculations and isothermal titration calorimetry. Histidine and citrate are promising ligands for improving zinc absorption from phytate-rich foods.

Complexation of carboxylate on smectite surfaces.

Science.gov (United States)

Liu, Xiandong; Lu, Xiancai; Zhang, Yingchun; Zhang, Chi; Wang, Rucheng

2017-07-19

We report a first principles molecular dynamics (FPMD) study of carboxylate complexation on clay surfaces. By taking acetate as a model carboxylate, we investigate its inner-sphere complexes adsorbed on clay edges (including (010) and (110) surfaces) and in interlayer space. Simulations show that acetate forms stable monodentate complexes on edge surfaces and a bidentate complex with Ca 2+ in the interlayer region. The free energy calculations indicate that the complexation on edge surfaces is slightly more stable than in interlayer space. By integrating pK a s and desorption free energies of Al coordinated water calculated previously (X. Liu, X. Lu, E. J. Meijer, R. Wang and H. Zhou, Geochim. Cosmochim. Acta, 2012, 81, 56-68; X. Liu, J. Cheng, M. Sprik, X. Lu and R. Wang, Geochim. Cosmochim. Acta, 2014, 140, 410-417), the pH dependence of acetate complexation has been revealed. It shows that acetate forms inner-sphere complexes on (110) in a very limited mildly acidic pH range while it can complex on (010) in the whole common pH range. The results presented in this study form a physical basis for understanding the geochemical processes involving clay-organics interactions.

Zinc oxide nanotubes decorated with silver nanoparticles as an ultrasensitive substrate for surface-enhanced Raman scattering

International Nuclear Information System (INIS)

Gao, M.; Feng, B.; Sun, Y.; Xing, G.; Li, S.; Yang, J.; Yang, L.; Zhang, Y.; Liu, H.; Fan, H.; Sui, Y.; Zhang, Z.; Liu, S.; Song, H.

2012-01-01

We report on the fabrication of a highly aligned silver-decorated array of zinc oxide nanotubes for use in surface-enhanced Raman spectroscopy (SERS). The ZnO nanotube array was first prepared by chemical etching, and the silver nanoparticles (AgNPs) were then deposited on their surface by magnetron sputtering. Such ZnO/Ag hybrid structures are shown to act as SERS-active substrates with remarkable sensitivity. The enhancement factor can be as high as 10 5 when using 4-mercaptopyridine in solution as a SERS probe. The synergistic combination between SERS 'hot spots' and the formation of an interfacial electric field between the zinc oxide nanotubes and the AgNPs in our opinion contribute to the high sensitivity. The relative standard deviations of signal intensities for the major SERS peaks are <7 %. This demonstrates that the optimized ZnO/Ag hybrid represents an excellent SERS substrate that may be used in trace analysis and ultrasensitive molecular sensing. (author)

Hemimorphite Ores: A Review of Processing Technologies for Zinc Extraction

Science.gov (United States)

Chen, Ailiang; Li, Mengchun; Qian, Zhen; Ma, Yutian; Che, Jianyong; Ma, Yalin

2016-10-01

With the gradual depletion of zinc sulfide ores, exploration of zinc oxide ores is becoming more and more important. Hemimorphite is a major zinc oxide ore, attracting much attention in the field of zinc metallurgy although it is not the major zinc mineral. This paper presents a critical review of the treatment for extraction of zinc with emphasis on flotation, pyrometallurgical and hydrometallurgical methods based on the properties of hemimorphite. The three-dimensional framework structure of hemimorphite with complex linkage of its structural units lead to difficult desilicification before extracting zinc in the many metallurgical technologies. It is found that the flotation method is generally effective in enriching zinc minerals from hemimorphite ores into a high-grade concentrate for recovery of zinc. Pure zinc can be produced from hemimorphite or/and willemite with a reducing reagent, like methane or carbon. Leaching reagents, such as acid and alkali, can break the complex structure of hemimorphite to release zinc in the leached solution without generation of silica gel in the hydrometallurgical process. For optimal zinc extraction, combing flotation with pyrometallurgical or hydrometallurgical methods may be required.

Beneficiation studies on low-grade complex polymetallic lead-zinc ore of duddar (lasbela) Balochistan, Pakistan

International Nuclear Information System (INIS)

Bhatti, M.R.; Kazim, K.R.; Mehmood, R.; Akram, A.

2016-01-01

A bench-scale beneficiation study was performed on low-grade complex lead-zinc ore of Duddar area, District Lasbela, Balochistan Province, Pakistan. The polymetallic ore under investigation contains galena and sphalerite as valuable minerals of lead and zinc. The low-grade ore was upgraded by selective sequential froth flotation technology to recover both minerals. An effort was made to investigate the effect of important variables on grade and recovery of concentrates and to design the process flow sheet. Different parameters of flotation process such as particle size of the feed, pH and % solids of the pulp, speed of impeller, type of reagents (collectors, frothers, regulators and modifiers) and their quantities, conditioning time and flotation time were optimized to attain maximum grade and recovery of respective concentrates. The rougher concentrates obtained were subjected to one regrinding and two cleaning operations to achieve higher-grade concentrates of both metals. Bench-scale flotation tests show that it is possible to obtain a lead concentrate assaying 65.24% Pb with recovery rate of 81.32% and a zinc concentrate containing 55.63% Zn content with recovery rate of 80.28%. Both the concentrates meet the specifications required for metallurgical and chemical grades. (author)

Electrochemical assessing corrosion inhibiting effects of zinc aluminum polyphosphate (ZAPP) as a modified zinc phosphate pigment

International Nuclear Information System (INIS)

Naderi, R.; Attar, M.M.

2008-01-01

Undesirable anti-corrosion performance of zinc phosphate pigment, the classical chromate replacement, has led researchers to take modification into account. Polyphosphate-based anti-corrosion pigments as a result of modification of zinc orthophosphate have been found to function much more efficiently. This study aimed to evaluate performance of steel samples immersed in 3.5% NaCl aqueous solution-containing zinc aluminum polyphosphate (ZAPP) pigment extract compared to those involving conventional zinc phosphate (ZP) pigment extract and also no pigment (blank) using electrochemical tests such as electrochemical impedance spectroscopy (EIS) and linear polarization (LP) as well as surface analysis. Impedance spectra and polarization curves revealed two different trends, showing the superiority of ZAPP pigment. Based on the results of scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), presence of a precipitated layer on the surface was confirmed when steel sample was immersed into the solution-containing ZAPP

Fabrication of bismuth superhydrophobic surface on zinc substrate

Science.gov (United States)

Yu, Tianlong; Lu, Shixiang; Xu, Wenguo; He, Ge

2018-06-01

The dendritic Bi/Bi2O3/ZnO superhydrophobic surface (SHPS) was facilely obtained on zinc substrate via etching in 0.5 mol L-1 HCl solution for 2 min, immersing in 2 mmol L-1 Bi(NO3)3/0.1 mol L-1 HNO3 solution for 2.5 min and annealing treatment at 180 °C for 2 h. The wetting property results demonstrated that the superhydrophobic sample had excellent water-repellency with a static water contact angle of 160° and sliding angle of 0° under the optimum condition, which can be visually confirmed by the impacting droplet could rebound back immediately and roll off the horizontally placed sample. Moreover, it exhibited remarkable self-cleaning ability, buoyancy, desired stability in long-term storage in air, corrosion resistance in 3.5 wt% NaCl solution, ice-over delay at - 16 °C and durability in lab-simulated abrasion test.

Excretion of Different Forms of Zinc by the prawn Palaemon serratus (Pennant)

International Nuclear Information System (INIS)

Small, L.F.; Keckes, S.; Fowler, S.W.

1976-01-01

Freshly collected speciments of Palaemon serratus from the upper Adriatic Sea were used to determine excretion rates of zinc in ''zinc-free'' water by anodic stripping polarographic techniques. Weight-specific excretion of total zinc varied reciprocally with body weight apparently in a log-log relationship. Weight-specific excretion of ionic-particulate zinc appeared greatest in short term (1-3 hr) experiments, while weight specific excretion of complexed zinc appeared greatest in longer term (4-5 hr) experiments; however, we cannot exclude the possibility that ionic-particulate zinc and dissolved organic compounds were excreted separately and subsequently combined in the water to yield zinc complex. (author)

Excretion of different forms of zinc by the prawn Palaemon serratus (Pennant)

International Nuclear Information System (INIS)

Small, L.F.; Keckes, S.; Fowler, S.W.

1974-01-01

Freshly collected specimens of Palaemon serratus from the upper Adriatic Sea were used to determine excretion rates of zinc in zinc-free water by anodic stripping polarographic techniques. Weight-specific excretion of total zinc varied reciprocally with body weight, apparently in a log--log relationship. Weight-specific excretion of ionic-particulate zinc appeared greatest in short term (1 to 3 hr) experiments, while weight-specific excretion of complexed zinc appeared greatest in longer term (4 to 5 hr) experiments; however, we cannot exclude the possibility that ionic-particulate zinc and dissolved organic compounds were excreted separately and subsequently combined in the water to yield zinc complex. (auth)

Decontamination of chemical-warfare agent simulants by polymer surfaces doped with the singlet oxygen generator zinc octaphenoxyphthalocyanine.

Science.gov (United States)

Gephart, Raymond T; Coneski, Peter N; Wynne, James H

2013-10-23

Using reactive singlet oxygen (1O2), the oxidation of chemical-warfare agent (CWA) simulants has been demonstrated. The zinc octaphenoxyphthalocyanine (ZnOPPc) complex was demonstrated to be an efficient photosensitizer for converting molecular oxygen (O2) to 1O2 using broad-spectrum light (450-800 nm) from a 250 W halogen lamp. This photosensitization produces 1O2 in solution as well as within polymer matrices. The oxidation of 1-naphthol to naphthoquinone was used to monitor the rate of 1O2 generation in the commercially available polymer film Hydrothane that incorporates ZnOPPc. Using electrospinning, nanofibers of ZnOPPc in Hydrothane and polycarbonate were formed and analyzed for their ability to oxidize demeton-S, a CWA simulant, on the surface of the polymers and were found to have similar reactivity as their corresponding films. The Hydrothane films were then used to oxidize CWA simulants malathion, 2-chloroethyl phenyl sulfide (CEPS), and 2-chloroethyl ethyl sulfide (CEES). Through this oxidation process, the CWA simulants are converted into less toxic compounds, thus decontaminating the surface using only O2 from the air and light.

Non-Chromate Passivation of Zinc

DEFF Research Database (Denmark)

Tang, Peter Torben; Bech-Nielsen, G.

1993-01-01

Phos). The treatments are within the same concentration region, and they have a mutual pat-ent pending. Although some tests still need to be conducted, the following aspects are clear at the present time: The general appearance of the passivated zinc surface is very similar to a standard yellow chromate treatment...... successfully. The corrosion resistance against white rust on zinc and zinc alloys is just as good as that of yellow chromate, although the result de-pends on the corrosion test method as well as on the nature of the zinc substrate pas-sivated. The passivation procedure is simply a dip for approxi-mately 2...

Mutations in the putative zinc-binding motif of UL52 demonstrate a complex interdependence between the UL5 and UL52 subunits of the human herpes simplex virus type 1 helicase/primase complex.

Science.gov (United States)

Chen, Yan; Carrington-Lawrence, Stacy D; Bai, Ping; Weller, Sandra K

2005-07-01

Herpes simplex virus type 1 (HSV-1) encodes a heterotrimeric helicase-primase (UL5/8/52) complex. UL5 contains seven motifs found in helicase superfamily 1, and UL52 contains conserved motifs found in primases. The contributions of each subunit to the biochemical activities of the complex, however, remain unclear. We have previously demonstrated that a mutation in the putative zinc finger at UL52 C terminus abrogates not only primase but also ATPase, helicase, and DNA-binding activities of a UL5/UL52 subcomplex, indicating a complex interdependence between the two subunits. To test this hypothesis and to further investigate the role of the zinc finger in the enzymatic activities of the helicase-primase, a series of mutations were constructed in this motif. They differed in their ability to complement a UL52 null virus: totally defective, partial complementation, and potentiating. In this study, four of these mutants were studied biochemically after expression and purification from insect cells infected with recombinant baculoviruses. All mutants show greatly reduced primase activity. Complementation-defective mutants exhibited severe defects in ATPase, helicase, and DNA-binding activities. Partially complementing mutants displayed intermediate levels of these activities, except that one showed a wild-type level of helicase activity. These data suggest that the UL52 zinc finger motif plays an important role in the activities of the helicase-primase complex. The observation that mutations in UL52 affected helicase, ATPase, and DNA-binding activities indicates that UL52 binding to DNA via the zinc finger may be necessary for loading UL5. Alternatively, UL5 and UL52 may share a DNA-binding interface.

Construction of an interatomic potential for zinc oxide surfaces by high-dimensional neural networks

Energy Technology Data Exchange (ETDEWEB)

Artrith, Nongnuch; Morawietz, Tobias; Behler, Joerg [Lehrstuhl fuer Theoretische Chemie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2011-07-01

Zinc oxide (ZnO) is a technologically important material with many applications, e.g. in heterogeneous catalysis. For theoretical studies of the structural properties of ZnO surfaces, defects, and crystal structures it is necessary to simulate large systems over long time-scales with sufficient accuracy. Often, the required system size is not accessible by computationally rather demanding density-functional theory (DFT) calculations. Recently, artificial Neural Networks (NN) trained to first principles data have shown to provide accurate potential-energy surfaces (PESs) for condensed systems. We present the construction and analysis of a NN PES for ZnO. The structural and energetic properties of bulk ZnO and ZnO surfaces are investigated using this potential and compared to DFT calculations.

Production of high purity granular metals: cadmium, zinc, lead

Directory of Open Access Journals (Sweden)

Shcherban A. P.

2017-04-01

Full Text Available Cadmium, zinc and lead are constituent components of many semiconductor compounds. The obtained high purity distillates and ingots are large-size elements, which is not always convenient to use, and thus require additional grinding, which does not always allow maintaining the purity of the original materials. For the growth of semiconductor and scintillation single crystals it is advisable to use "friable" granular high-purity distillates, which can be processed without the risk of contamination. For example, the European low-background experiment LUCIFER required more than 20 kg of high-purity granulated zinc, which was agreed to be supplied by NSC KIPT. This task was then extended to cadmium and lead. Motivated by these tasks, the authors of this paper propose complex processes of deep refining of cadmium, zinc and lead by vacuum distillation. A device producing granules has been developed. The process of granulation of high-purity metals is explored. The purity of produced granules for cadmium and zinc is >99,9999, and >99,9995% for lead granules. To prevent oxidation of metal granules during exposition to air, chemical methods of surface passivation were used. Organic solvent based on dimethylformamide used as a coolant improves the resistance of granules to atmospheric corrosion during the granulation of high purity Cd, Zn and Pb.

Steric Effects on the Binding of Phosphate and Polyphosphate Anions by Zinc(II) and Copper(II) Dinuclear Complexes of m-Xylyl-bis-cyclen.

Science.gov (United States)

Esteves, Catarina V; Esteban-Gómez, David; Platas-Iglesias, Carlos; Tripier, Raphaël; Delgado, Rita

2018-05-11

The triethylbenzene-bis-cyclen (cyclen = 1,4,7,10-tetraazacyclododecane) compound (tbmce) was designed with an imposed structural rigidity at the m-xylyl spacer to be compared to a less restrained and known parent compound (bmce). The framework of both compounds differs only in the substituents of the m-xylyl spacer. The study was centered in the differences observed in the acid-base reactions of both compounds, their copper(II) and zinc(II) complexation behaviors, as well as in the uptake of phosphate and polyphosphate anions (HPPi 3- , ATP 4- , ADP 3- , AMP 2- , PhPO 4 2- , and HPO 4 2- ). On the one hand, the acid-base reactions showed lower values for the third and fourth protonation constants of tbmce than for bmce, suggesting that the ethyl groups of the spacer in tbmce force the two cyclen units to more conformational restricted positions. On the other hand, the stability constant values for copper(II) and zinc(II) complexes revealed that bmce is a better chelator than tbmce pointing out to additional conformational restraints imposed by the triethylbenzene spacer. The binding studies of phosphates by the dinuclear copper(II) and zinc(II) complexes showed much smaller effective association constants for the dicopper complexes. Single-crystal X-ray and computational (density functional theory) studies suggest that anion binding promotes the formation of tetranuclear entities in which anions are bridging the metal centers. Our studies also revealed the dinuclear zinc(II) complex of bmce as a promising receptor for phosphate anions, with the largest effective association constant of 5.94 log units being observed for the formation of [Zn 2 bmce(HPPi)] + . Accordingly, a colorimetric study via an indicator displacement assay to detect phosphates in aqueous solution found that the [Zn 2 bmce] 4+ complex acts as the best receptor for pyrophosphate displaying a detection limit of 2.5 nM by changes visible to naked eye.

Zinc and nickel removal in limestone based treatment of acid mine drainage: The relative role of adsorption and co-precipitation

International Nuclear Information System (INIS)

Miller, Andrew; Wildeman, Thomas; Figueroa, Linda

2013-01-01

Highlights: • Limestone treatment of mining impacted water was simulated in batch reactors. • Zinc and nickel removals were quantified/characterized with a sequential extraction. • Removals were described with a surface complexation and a surface precipitation model. • Extraction/modeling results imply mechanisms beyond adsorption dominate metal removal. - Abstract: Mining influenced water may contain high metal and sulfate loads, and have low pH (acid mine drainage). Removal of these metals prior to environmental discharge is critical to maintain ecosystem vitality. Limestone based passive treatment systems are commonly used for pH neutralization. The same conditions that lead to pH neutralization may also remove a substantial amount of metals from solution, but the connection between treatment conditions and metal removal are not well understood. In this study, zinc and nickel removals are quantified in batch reactor simulated limestone treatment of acid mine drainage. The resulting solid phase is characterized with a sequential extraction procedure, and the removals are interpreted using surface complexation and surface precipitation models. Zinc and nickel removals are closely linked to the initial iron concentration in the mine water, but are also affected by pH, alkalinity, calcium and sulfate concentrations. The surface complexation model was based on literature descriptions of hydrous ferric oxide. In order to obtain a sufficient fit to the data, the surface site density was increased to an unrealistically high value. Uptake data was also fit to an existing surface precipitation model. The values used are similar to those found in previous studies. Both models indicate that adsorption is not the dominant removal process in the treatment system. Using adsorption only models will generally underpredict metal removals within limestone based treatment systems

Characterization of Zinc Oxide (ZnO) piezoelectric properties for Surface Acoustic Wave (SAW) device

Science.gov (United States)

Rosydi Zakaria, Mohd; Johari, Shazlina; Hafiz Ismail, Mohd; Hashim, Uda

2017-11-01

In fabricating Surface Acoustic Wave (SAW) biosensors device, the substrate is one of important factors that affected to performance device. there are many types of piezoelectric substrate in the markets and the cheapest is zinc Oxide substrate. Zinc Oxide (ZnO) with its unique properties can be used as piezoelectric substrate along with SAW devices for detection of DNA in this research. In this project, ZnO thin film is deposited onto silicon oxide substrate using electron beam evaporation (E-beam) and Sol-Gel technique. Different material structure is used to compare the roughness and best piezoelectric substrate of ZnO thin film. Two different structures of ZnO target which are pellet and granular are used for e-beam deposition and one sol-gel liquid were synthesize and compared. Parameter for thickness of ZnO e-beam deposition is fixed to a 0.1kÅ for both materials structure and sol-gel was coat using spin coat technique. After the process is done, samples are annealed at temperature of 500°C for 2 hours. The structural properties of effect of post annealing using different material structure of ZnO are studied using Atomic Force Microscopic (AFM) for surface morphology and X-ray Diffraction (XRD) for phase structure.

(Pyridine)(tetrahydroborato)zinc complex, (Zn(BH{sub 4}){sub 2}(py)), as a new stable, efficient and chemoselective reducing agent for reduction of carbonyl compounds

Energy Technology Data Exchange (ETDEWEB)

Zeynizadeh, Behzad; Faraji, Fariba [Urima Univ., Urima (Iran, Islamic Republic of)

2003-04-01

(Pyridine)(tetrahydroborato)zinc complex, (Zn(BH{sub 4}){sub 2}(py)), as a stable white solid, was prepared quantitatively by complexation of an equimolar amount of zinc tetrahydroborate and pyridine at room temperature. This reagent can easily reduce variety of carbonyl compounds such as aldehydes, ketones, acyloins, {alpha}-diketones and {alpha},{beta}-unsaturated carbonyl compounds to their corresponding alcohols in good to excellent yields. Reduction reactions were performed in ether or THF at room temperature or under reflux conditions. In addition, the chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing agent.

Effects of nanorod structure and conformation of fatty acid self-assembled layers on superhydrophobicity of zinc oxide surface.

Science.gov (United States)

Badre, Chantal; Dubot, P; Lincot, Daniel; Pauporte, Thierry; Turmine, Mireille

2007-12-15

Superhydrophobic surfaces have been prepared from nanostructured zinc oxide layers by a treatment with fatty acid molecules. The layers are electrochemically deposited from an oxygenated aqueous zinc chloride solution. The effects of the layer's structure, from a dense film to that of a nanorod array, as well as that of the properties of the fatty acid molecules based on C18 chains are described. A contact angle (CA) as high as 167 degrees is obtained with the nanorod structure and the linear saturated molecule (stearic acid). Lower values are found with molecules having an unsaturated bond on C9, in particular with a cis conformation (140 degrees ). These results, supplemented by infrared spectroscopy, indicate an enhancement of the sensitivity to the properties of the fatty acid molecules (conformation, flexibility, saturated or not) when moving from the flat surface to the nanostructured surface. This is attributed to a specific influence of the structure of the tops of the rods and lateral wall properties on the adsorption and organization of the molecules. CA measurements show a very good stability of the surface in time if stored in an environment protected from UV radiations.

Critical rate of electrolyte circulation for preventing zinc dendrite formation in a zinc-bromine redox flow battery

Science.gov (United States)

Yang, Hyeon Sun; Park, Jong Ho; Ra, Ho Won; Jin, Chang-Soo; Yang, Jung Hoon

2016-09-01

In a zinc-bromine redox flow battery, a nonaqueous and dense polybromide phase formed because of bromide oxidation in the positive electrolyte during charging. This formation led to complicated two-phase flow on the electrode surface. The polybromide and aqueous phases led to different kinetics of the Br/Br- redox reaction; poor mixing of the two phases caused uneven redox kinetics on the electrode surface. As the Br/Br- redox reaction was coupled with the zinc deposition reaction, the uneven redox reaction on the positive electrode was accompanied by nonuniform zinc deposition and zinc dendrite formation, which degraded battery stability. A single-flow cell was operated at varying electrolyte circulation rates and current densities. Zinc dendrite formation was observed after cell disassembly following charge-discharge testing. In addition, the flow behavior in the positive compartment was observed by using a transparent version of the cell. At low rate of electrolyte circulation, the polybromide phase clearly separated from the aqueous phase and accumulated at the bottom of the flow frame. In the corresponding area on the negative electrode, a large amount of zinc dendrites was observed after charge-discharge testing. Therefore, a minimum circulation rate should be considered to avoid poor mixing of the positive electrolyte.

Studies on the fate of applied zinc and its distribution among different chemical pools using zinc-65

International Nuclear Information System (INIS)

Ahmed, Sultana; Rahaman, S.M.

1991-01-01

Investigations were carried out to study the fate of applied zinc and its distribution among different soil zinc fractions in 15 surface soils (0 to 30 cm depth) of Bangladesh. 65 Zn was used in the study. (author). 9 refs., 2 tabs., 2 figs

Effect of heavy metals on soil mineral surfaces and bioretention pond performance

Science.gov (United States)

Zhang, H.; Olson, M. S.

2009-12-01

Haibo Zhang and Mira S. Olson Department of Civil, Architectural, and Environmental Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 As urban stormwater runoff flows across impervious surfaces, it collects and accumulates pollutants that are detrimental to the quality of local receiving water bodies. Heavy metal pollution, such as copper, lead and zinc, has been a concern in urban stormwater runoff. In addition, the presence of bacteria in stormwater has been frequently reported. The co-existence of both heavy metals and bacteria in stormwater and their complex interactions determine their transport and removal through bioretention pond. Stormwater runoff was sampled from a bioretention pond in Philadelphia, PA. The concentration of copper, lead and zinc were measured as 0.086ppm, 0.083ppm and 0.365ppm, respectively. Batch experiments were conducted with solutions of pure copper, lead and zinc, and with a synthetic stormwater solution amended with copper, lead and zinc. The solution was buffered to pH 7, within the range of the observed stormwater pH. In pure heavy metal solutions, the sorption of copper, lead and zinc onto soil are 96%, 99% and 85%, respectively. In synthetic stormwater containing nutrients and all three metals, the sorption of lead is 97%, while copper and zinc decrease to 29% and 71%, respectively. Mineralogy of a soil sample taken from the bioretention pond was analyzed using a scanning electron microscope (SEM) and compared before and after sorption experiments. Sorption and complexation of heavy metals is likely to change the mineralogy of soil particle surfaces, which will affect the attachment of bacteria and therefore its transport through soil. This study will benefit long-term predictions of the performance of bioretention ponds for urban stormwater runoff treatment. Keyword: Heavy metal pollution, sorption, surface complexation, urban stormwater runoff, bioretention pond

Zinc-ion implanted and deposited titanium surfaces reduce adhesion of Streptococccus mutans

International Nuclear Information System (INIS)

Xu Juan; Ding Gang; Li Jinlu; Yang Shenhui; Fang Bisong; Sun Hongchen; Zhou Yanmin

2010-01-01

While titanium (Ti) is a commonly used dental implant material with advantageous biocompatible and mechanical properties, native Ti surfaces do not have the ability to prevent bacterial colonization. The objective of this study was to evaluate the chemical composition and bacterial adhesive properties of zinc (Zn) ion implanted and deposited Ti surfaces (Zn-PIIID-Ti) as potential dental implant materials. Surfaces of pure Ti (cp-Ti) were modified with increasing concentrations of Zn using plasma immersion ion implantation and deposition (PIIID), and elemental surface compositions were characterized by X-ray photoelectron spectrometry (XPS). To evaluate bacterial responses, Streptococcus mutans were seeded onto the modifiedTi surfaces for 48 h and subsequently observed by scanning electron microscopy. Relative numbers of bacteria on each surface were assessed by collecting the adhered bacteria, reculturing and counting colony forming units after 48 h on bacterial grade plates. Ti, oxygen and carbon elements were detected on all surfaces by XPS. Increased Zn signals were detected on Zn-PIIID-Ti surfaces, correlating with an increase of Zn-deposition time. Substantial numbers of S. mutans adhered to cp-Ti samples, whereas bacterial adhesion on Zn-PIIID-Ti surfaces signficantly decreased as the Zn concentration increased (p < 0.01). In conclusion, PIIID can successfully introduce Zn onto a Ti surface, forming a modified surface layer bearing Zn ions that consequently deter adhesion of S. mutans, a common bacterium in the oral environment.

Zinc-ion implanted and deposited titanium surfaces reduce adhesion of Streptococccus mutans

Energy Technology Data Exchange (ETDEWEB)

Xu Juan, E-mail: doctorxue@126.com [Implant Center, School of Stomatology Jilin University, Changchun, Jilin (China) and Stomatological Hospital, Urumqi, Xinjiang (China); Ding Gang [Department of Stomatology, Yidu Central Hospital, Weifang, Shandong (China); Capital Medical University School of Stomatology, Beijing (China); Li Jinlu; Yang Shenhui; Fang Bisong [Capital Medical University School of Stomatology, Beijing (China); Sun Hongchen, E-mail: hcsun@jlu.edu.cn [Implant Center, School of Stomatology Jilin University, Changchun, Jilin (China); Zhou Yanmin, E-mail: zhouym62@126.com [Implant Center, School of Stomatology Jilin University, Changchun, Jilin (China)

2010-10-01

While titanium (Ti) is a commonly used dental implant material with advantageous biocompatible and mechanical properties, native Ti surfaces do not have the ability to prevent bacterial colonization. The objective of this study was to evaluate the chemical composition and bacterial adhesive properties of zinc (Zn) ion implanted and deposited Ti surfaces (Zn-PIIID-Ti) as potential dental implant materials. Surfaces of pure Ti (cp-Ti) were modified with increasing concentrations of Zn using plasma immersion ion implantation and deposition (PIIID), and elemental surface compositions were characterized by X-ray photoelectron spectrometry (XPS). To evaluate bacterial responses, Streptococcus mutans were seeded onto the modifiedTi surfaces for 48 h and subsequently observed by scanning electron microscopy. Relative numbers of bacteria on each surface were assessed by collecting the adhered bacteria, reculturing and counting colony forming units after 48 h on bacterial grade plates. Ti, oxygen and carbon elements were detected on all surfaces by XPS. Increased Zn signals were detected on Zn-PIIID-Ti surfaces, correlating with an increase of Zn-deposition time. Substantial numbers of S. mutans adhered to cp-Ti samples, whereas bacterial adhesion on Zn-PIIID-Ti surfaces signficantly decreased as the Zn concentration increased (p < 0.01). In conclusion, PIIID can successfully introduce Zn onto a Ti surface, forming a modified surface layer bearing Zn ions that consequently deter adhesion of S. mutans, a common bacterium in the oral environment.

Positron annihilation studies of bio-related N2S2-tetradentate ligands and their zinc complexes

International Nuclear Information System (INIS)

Shaban, S.Y.; Mahmoud, K.R.; Sharshar, T.

2013-01-01

In this study, a series of three N 2 S 2 -tetradentate ligands and their zinc complexes were investigated by positron annihilation lifetime spectroscopy. The measurements were performed at room temperature. The analysis of lifetime spectra of all samples yielded four lifetime components, except in one sample that yielded three components. The results showed that the formation probability and lifetime of ortho-positronium in this series are dependent on the structure.

Zinc-nickel alloy electrodeposits for water electrolysis

Energy Technology Data Exchange (ETDEWEB)

Sheela, G.; Pushpavanam, Malathy; Pushpavanam, S. [Central Electrochemical Research Inst., Karaikudi (India)

2002-06-01

Electrodeposited zinc-nickel alloys of various compositions were prepared. A suitable electrolyte and conditions to produce alloys of various compositions were identified. Alloys produced on electroformed nickel foils were etched in caustic to leach out zinc and to produce the Raney type, porous electro catalytic surface for hydrogen evolution. The electrodes were examined by polarisation measurements, to evaluate their Tafel parameters, cyclic voltammetry, to test the change in surface properties on repeated cycling, scanning electron microscopy to identify their microstructure and X-ray diffraction. The catalytic activity as well as the life of the electrode produced from 50% zinc alloy was found to be better than others. (Author)

Preparation of Zinc Oxide (ZnO) Thin Film as Transparent Conductive Oxide (TCO) from Zinc Complex Compound on Thin Film Solar Cells: A Study of O2 Effect on Annealing Process

Science.gov (United States)

Muslih, E. Y.; Kim, K. H.

2017-07-01

Zinc oxide (ZnO) thin film as a transparent conductive oxide (TCO) for thin film solar cell application was successfully prepared through two step preparations which consisted of deposition by spin coating at 2000 rpm for 10 second and followed by annealing at 500 °C for 2 hours under O2 and ambient atmosphere. Zinc acetate dehydrate was used as a precursor which dissolved in ethanol and acetone (1:1 mol) mixture in order to make a zinc complex compound. In this work, we reported the O2 effect, reaction mechanism, structure, morphology, optical and electrical properties. ZnO thin film in this work shows a single phase of wurtzite, with n-type semiconductor and has band gap, carrier concentration, mobility, and resistivity as 3.18 eV, 1.21 × 10-19cm3, 11 cm2/Vs, 2.35 × 10-3 Ωcm respectively which is suitable for TCO at thin film solar cell.

Hydrogen-related complexes in Li-diffused ZnO single crystals

Science.gov (United States)

Corolewski, Caleb D.; Parmar, Narendra S.; Lynn, Kelvin G.; McCluskey, Matthew D.

2016-07-01

Zinc oxide (ZnO) is a wide band gap semiconductor and a potential candidate for next generation white solid state lighting applications. In this work, hydrogen-related complexes in lithium diffused ZnO single crystals were studied. In addition to the well-known Li-OH complex, several other hydrogen defects were observed. When a mixture of Li2O and ZnO is used as the dopant source, zinc vacancies are suppressed and the bulk Li concentration is very high (>1019 cm-3). In that case, the predominant hydrogen complex has a vibrational frequency of 3677 cm-1, attributed to surface O-H species. When Li2CO3 is used, a structured blue luminescence band and O-H mode at 3327 cm-1 are observed at 10 K. These observations, along with positron annihilation measurements, suggest a zinc vacancy-hydrogen complex, with an acceptor level ˜0.3 eV above the valence-band maximum. This relatively shallow acceptor could be beneficial for p-type ZnO.

Hydrogen-related complexes in Li-diffused ZnO single crystals

International Nuclear Information System (INIS)

Corolewski, Caleb D.; Parmar, Narendra S.; Lynn, Kelvin G.; McCluskey, Matthew D.

2016-01-01

Zinc oxide (ZnO) is a wide band gap semiconductor and a potential candidate for next generation white solid state lighting applications. In this work, hydrogen-related complexes in lithium diffused ZnO single crystals were studied. In addition to the well-known Li-OH complex, several other hydrogen defects were observed. When a mixture of Li_2O and ZnO is used as the dopant source, zinc vacancies are suppressed and the bulk Li concentration is very high (>10"1"9" cm"−"3). In that case, the predominant hydrogen complex has a vibrational frequency of 3677 cm"−"1, attributed to surface O-H species. When Li_2CO_3 is used, a structured blue luminescence band and O-H mode at 3327 cm"−"1 are observed at 10 K. These observations, along with positron annihilation measurements, suggest a zinc vacancy–hydrogen complex, with an acceptor level ∼0.3 eV above the valence-band maximum. This relatively shallow acceptor could be beneficial for p-type ZnO.

Zinc Addition Effects on General Corrosion of Austenitic Stainless Steels in PWR Primary Conditions

International Nuclear Information System (INIS)

Qiao Peipeng; Zhang Lefu; Liu Ruiqin; Jiang Suqing; Zhu Fawen

2010-01-01

Zinc addition effects on general corrosion of austenitic stainless steel 316 and 304 were investigated in simulated PWR primary coolant without zinc or with 50 ppb zinc addition at 315 degree C for 500 h. The results show that with the addition of zinc, the corrosion rate of austenitic stainless steel is effectively reduced, the surface oxide film is thinner, the morphology and chemical composition of surface oxide scales are evidently different from those without zinc. There are needle-like corrosion products on the surface of stainless steel 304. (authors)

The development of a micropatterned electrode for studies of zinc electrodeposition

Energy Technology Data Exchange (ETDEWEB)

Sutija, Dave P. [Univ. of California, Berkeley, CA (United States); Muller, Rolf H. [Univ. of California, Berkeley, CA (United States); Tobias, Charles W. [Univ. of California, Berkeley, CA (United States)

1986-12-01

A micropatterned electrode was prepared for the study of electrocrystallization. Using microphotolithography, in conjunction with evaporation and pulse electrodeposition of thin films, a set of artificially roughened electrodes with hemispherical surface features five microns in diameter was developed. Voltammetric studies were conducted to determine the best electrode material. Gold, platinum, and various carbon surfaces were evaluated for zinc nucleation density and hydrogen overpotential. Surface homogeneity was examined by both light and scanning electron microscopy. Gold was determined to possess the best combination of material properties: chemical inertness, low melting point, and a high work function allowing underpotential deposition of zinc which reduces the rate of hydrogen evolution. Stripping coulometry was employed to determine zinc limiting currents, and evaluate effective diffusion coefficients in concentrated zinc chloride solutions. Although the method worked well for dilute zinc chloride and copper sulfate solutions, it failed at higher current densities; the emergence of surface roughness obscured actual limiting current plateaus.

Zinc fingers, zinc clusters, and zinc twists in DNA-binding protein domains

International Nuclear Information System (INIS)

Vallee, B.L.; Auld, D.S.; Coleman, J.E.

1991-01-01

The authors recognize three distinct motifs of DNA-binding zinc proteins: (i) zinc fingers, (ii) zinc clusters, and (iii) zinc twists. Until very recently, x-ray crystallographic or NMR three-dimensional structure analyses of DNA-binding zinc proteins have not been available to serve as standards of reference for the zinc binding sites of these families of proteins. Those of the DNA-binding domains of the fungal transcription factor GAL4 and the rat glucocorticoid receptor are the first to have been determined. Both proteins contain two zinc binding sites, and in both, cysteine residues are the sole zinc ligands. In GAL4, two zinc atoms are bound to six cysteine residues which form a zinc cluster akin to that of metallothionein; the distance between the two zinc atoms of GAL4 is ∼3.5 angstrom. In the glucocorticoid receptor, each zinc atom is bound to four cysteine residues; the interatomic zinc-zinc distance is ∼13 angstrom, and in this instance, a zinc twist is represented by a helical DNA recognition site located between the two zinc atoms. Zinc clusters and zinc twists are here recognized as two distinctive motifs in DNA-binding proteins containing multiple zinc atoms. For native zinc fingers, structural data do not exist as yet; consequently, the interatomic distances between zinc atoms are not known. As further structural data become available, the structural and functional significance of these different motifs in their binding to DNA and other proteins participating in the transmission of the genetic message will become apparent

Zinc chelates as new activators for sulphur vulcanization of acrylonitrile-butadiene elastomer

Directory of Open Access Journals (Sweden)

2009-04-01

Full Text Available The goal of this work was to apply several zinc chelates as activators for sulphur vulcanization of acrylonitrilebutadiene elastomer (NBR, in order to find alternatives for the conventionally used zinc oxide. In this article, we discuss the effects of different zinc complexes on the cure characteristics, crosslinks distribution in the elastomer network and mechanical properties of acrylonitrile-butadiene rubber. Zinc chelates seem to be good substitutes for zinc oxide as activators for sulphur vulcanization of NBR rubber, without detrimental effects on the crosslinking process and physical properties of the obtained vulcanizates. Moreover, application of zinc complexes allows to reduce the amount of zinc ions in rubber compounds by 40% compared to conventionally crosslinked vulcanizates with zinc oxide. It is a very important ecological goal since zinc oxide is classified as toxic to aquatic species and its amount in rubber products must be reduced below 2.5% at least. From a technological point of view it is a very important challenge.

A study on the isotope effects in the reduction of carbon dioxide by zinc; Etude des effets isotopiques dans la reduction du gaz carbonique par le zinc

Energy Technology Data Exchange (ETDEWEB)

Senegacnik, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1957-06-15

We have determined the isotope effects which occur in the reduction of carbon dioxide by zinc. It has been shown that in the case of irreversible surface reactions, Bernstein's equation which permits the calculation of the fractionation factor is still valid. These experimental factors are in good agreement with those obtained by calculating the partition functions of the adsorbed activated complexes. In the reaction mechanism used, the model of the activated complex corresponds to the dissociation of one of the carbon oxygen bonds CO{sub 2} {yields} CO + O. Perturbations arising from the slight reversibility of the reaction Zn + CO{sub 2} {r_reversible} ZnO + CO on the isotope effects on the carbon and oxygen atoms have also been calculated. (author) [French] Nous avons etudie les effets isotopiques qui ont lieu dans la reduction du gaz carbonique par le zinc. La validite de l'equation de Bernstein qui permet de calculer le facteur de fractionnement a ete demontree pour le cas d'une reaction irreversible de surface. Ces facteurs de fractionnement experimentaux sont en bon accord avec ceux obtenus par le calcul des fonctions de partition isotopiques des complexes actives adsorbes. Dans le mecanisme de reaction utilise, le modele du complexe active correspond a la dissociation d'une des liaisons carbone oxygene CO{sub 2} {yields} CO + O. Les effets perturbateurs de la reversibilite de la reduction Zn + CO{sub 2} {r_reversible} ZnO + CO sur les effets isotopiques du carbone et ceux de l'oxygene ont ete egalement evalues. (auteur)

A study on the isotope effects in the reduction of carbon dioxide by zinc; Etude des effets isotopiques dans la reduction du gaz carbonique par le zinc

Energy Technology Data Exchange (ETDEWEB)

Senegacnik, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1957-06-15

We have determined the isotope effects which occur in the reduction of carbon dioxide by zinc. It has been shown that in the case of irreversible surface reactions, Bernstein's equation which permits the calculation of the fractionation factor is still valid. These experimental factors are in good agreement with those obtained by calculating the partition functions of the adsorbed activated complexes. In the reaction mechanism used, the model of the activated complex corresponds to the dissociation of one of the carbon oxygen bonds CO{sub 2} {yields} CO + O. Perturbations arising from the slight reversibility of the reaction Zn + CO{sub 2} {r_reversible} ZnO + CO on the isotope effects on the carbon and oxygen atoms have also been calculated. (author) [French] Nous avons etudie les effets isotopiques qui ont lieu dans la reduction du gaz carbonique par le zinc. La validite de l'equation de Bernstein qui permet de calculer le facteur de fractionnement a ete demontree pour le cas d'une reaction irreversible de surface. Ces facteurs de fractionnement experimentaux sont en bon accord avec ceux obtenus par le calcul des fonctions de partition isotopiques des complexes actives adsorbes. Dans le mecanisme de reaction utilise, le modele du complexe active correspond a la dissociation d'une des liaisons carbone oxygene CO{sub 2} {yields} CO + O. Les effets perturbateurs de la reversibilite de la reduction Zn + CO{sub 2} {r_reversible} ZnO + CO sur les effets isotopiques du carbone et ceux de l'oxygene ont ete egalement evalues. (auteur)

Effects of size and surface of zinc oxide and aluminum-doped zinc oxide nanoparticles on cell viability inferred by proteomic analyses

Directory of Open Access Journals (Sweden)

Pan CH

2014-08-01

Full Text Available Chih-Hong Pan,1,2,* Wen-Te Liu,3,4,* Mauo-Ying Bien,4,5 I-Chan Lin,6 Ta-Chih Hsiao,7 Chih-Ming Ma,8 Ching-Huang Lai,2 Mei-Chieh Chen,9 Kai-Jen Chuang,10,11 Hsiao-Chi Chuang3,4 On behalf of the Taiwan CardioPulmonary Research (T-CPR Group 1Institute of Labor, Occupational Safety and Health, Ministry of Labor, 2School of Public Health, National Defense Medical Center, 3Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, 4School of Respiratory Therapy, College of Medicine, 5Division of Pulmonary Medicine, Department of Internal Medicine, Taipei Medical University Hospital, 6Department of Ophthalmology, Shuang Ho Hospital, Taipei Medical University, Taipei, 7Graduate Institute of Environmental Engineering, National Central University, Taoyuan, 8Department of Cosmetic Application and Management, St Mary’s Junior College of Medicine, Nursing and Management, Sanxing, 9Department of Microbiology and Immunology, College of Medicine, 10Department of Public Health, School of Medicine, College of Medicine, 11School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan *These authors contributed equally to this work Abstract: Although the health effects of zinc oxide nanoparticles (ZnONPs on the ­respiratory system have been reported, the fate, potential toxicity, and mechanisms in biological cells of these particles, as related to particle size and surface characteristics, have not been well elucidated. To determine the physicochemical properties of ZnONPs that govern cytotoxicity, we investigated the effects of size, electronic properties, zinc concentration, and pH on cell viability using human alveolar-basal epithelial A549 cells as a model. We observed that a 2-hour or longer exposure to ZnONPs induced changes in cell viability. The alteration in cell viability was associated with the zeta potentials and pH values of the ZnONPs. Proteomic profiling of A549 exposed to Zn

Preparation of surface modified zinc oxide nanoparticle with high capacity dye removal ability

International Nuclear Information System (INIS)

Mahmoodi, Niyaz Mohammad; Najafi, Farhood

2012-01-01

Highlights: ► Amine-functionalized zinc oxide nanoparticle (AFZON) was synthesized. ► Isotherm and kinetics data followed Langmuir isotherm and pseudo-second order kinetic model, respectively. ► Q 0 of ZON for AB25, DR23 and DR31 was 20, 12 and 15 mg/g, respectively. ► Q 0 of AFZON for AB25, DR23 and DR31 was 1250, 1000 and 1429 mg/g, respectively. ► AFZON was regenerated at pH 12. -- Abstract: In this paper, the surface modification of zinc oxide nanoparticle (ZON) by amine functionalization was studied to prepare high capacity adsorbent. Dye removal ability of amine-functionalized zinc oxide nanoparticle (AFZON) and zinc oxide nanoparticle (ZON) was also investigated. The physical characteristics of AFZON were studied using Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Acid Blue 25 (AB25), Direct Red 23 (DR23) and Direct Red 31 (DR31) were used as model compounds. The effect of operational parameters such as dye concentration, adsorbent dosage, pH and salt on dye removal was evaluated. The isotherm and kinetic of dye adsorption were studied. The maximum dye adsorption capacity (Q 0 ) was 20 mg/g AB25, 12 mg/g DR23 and 15 mg/g DR31 for ZON and 1250 mg/g AB25, 1000 mg/g DR23 and 1429 mg/g DR31 for AFZON. It was found that dye adsorption followed Langmuir isotherm. Adsorption kinetic of dyes was found to conform to pseudo-second order kinetics. Dye desorption tests (adsorbent regeneration) showed that the maximum dye release of 90% AB25, 86% for DR23 and 90% for DR31 were achieved in aqueous solution at pH 12. Based on the data of the present investigation, it can be concluded that the AFZON being an adsorbent with high dye adsorption capacity might be a suitable alternative to remove dyes from colored aqueous solutions.

Post-synthetic modification of mesoporous zinc-adeninate framework with tris(2,2′-biprydine) ruthenium(II) complex and its electrochemiluminescence

Energy Technology Data Exchange (ETDEWEB)

Park, Ji Eun; Shin, Ik Soo [Dept. of Chemistry, Soongsil University, Seoul (Korea, Republic of); Oh, Hye Jae; An, Ji Hyun [Dept. of Chemistry Education, Seoul National University, Seoul (Korea, Republic of)

2017-04-15

Herein we report a redox-active metal-organic framework (MOF) via post-synthetic cation exchange with tris(2,2′-biprydine) ruthenium(II) complex (Ru(bpy){sub 3}{sup 2+}). A porous anionic zinc-adeninate framework (bMOF-100) is spacious enough to easily entrap 2.43 of Ru(bpy){sub 3}{sup 2+} cations within the mesopore. The encapsulation supported the framework structure preventing any distortion from a rapid solvent evaporation under SEM observation. Ru(bpy){sub 3}{sup 2+}@bMOF-100 was then immobilized on the surface of glassy carbon electrode, and its electrocatalytic and electrochemiluminescent (ECL) properties were investigated in aqueous and organic solution. Especially, Ru(bpy){sub 3}{sup 2+}@bMOF-100 showed the excellent electrochemical properties of Ru(bpy){sub 3}{sup 2+}, but gradual decomposition of the MOF structure was observed under electrochemical measurements because of the sluggish oxidation of adeninate ligand.

Etude multi-échelle des mécanismes d'élaboration de revêtements d'alliage zinc-nickel à base d'électrolytes alcalins : germination, complexation et structures cristallines

OpenAIRE

Fedi , Baptiste

2016-01-01

The present work aims to deepen the understanding of the mechanisms of zinc-nickelelectrodeposition in alkaline baths. Zinc-nickel deposits containing between 12% and 16%nickel known for their anti-corrosion performance. Complexing agents are required toobtain soluble and reactive nickel forms, and to stabilize the electrolytes. A study ofthe complexing mechanisms has improved the understanding of their respective role andbehavior, and their influence on the stability and the morphology and c...

Assessing the speciation pattern of lead and zinc in surface water collected from Abegede creek, Ijora and Lagos

International Nuclear Information System (INIS)

Adeniyi, A.A.; Okedeyi, O.O.

2004-01-01

A two stage sequential extraction procedure for the speciation of zinc and lead has been applied to surface water randomly collected from three sites in Abegede Creek, Ijora and Lagos. The determination of the labile and non-labile metals species was carried out by flame atomic absorption spectrophotometry (FAAS). The mean values of non-labile zinc and lead concentrations from the three sites, A, B and Care 0.54 minus plus 0.25 mg/l; 0.55 plus minus 0.26 mg/l;1.13 plus 0.76 mg/l; respectively for zinc and 0.13 plus minus 0.09 mg/l; 0.17 plus minus 0.07 mg/l;0.42 plus minus 0.23 mg/l respectively for lead. These are higher than for the labile species in the three sites;0.14 plus minus 0.07 mg/l; 0.21 plus minus 0.22 mg/l; 0.73 plus minus 0.82 mg/l, respectively for zinc and ND; 0.02 plus minus 0.04 mg/l; 0.16 plus minus 0.22 mg/l, respectively for lead. The statistical analysis of variance of the distribution of zinc and lead in the three sites were estimated at 95% confidence level. The values of metal and obtained were compared with Nigeria's background values for some rivers and the World Health Organization limits for drinking water respectively and found to be generally higher especially for lead levels. The probable sources of zinc and lead in the Creek are from natural and point sources, although there could be non-point source contributions from urban run-offs and vehicular exhaust. (author)

Effect of Zinc Oxide Doping on Electroluminescence and Electrical Behavior of Metalloporphyrins-Doped Samarium Complex

Science.gov (United States)

Janghouri, Mohammad; Amini, Mostafa M.

2018-02-01

Samarium complex [(Sm(III)] as a new host material was used for preparation of red organic light-emitting diodes (OLEDs). Devices with configurations of indium-doped tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):(poly(styrenesulfonate) (PEDOT:PSS (50 nm)/polyvinyl carbazole (PVK):[zinc oxide (ZnO)] (50 nm)/[(Sm(III)]:[zinc(II) 2,3-tetrakis(dihydroxyphenyl)-porphyrin and Pt(II) 2,3-dimethoxyporphyrin] (60 nm)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) (15 nm)/Al (150 nm) have been fabricated and investigated. An electroplex occurring at the (PVK/Sm: Pt(II) 2,3-dimethoxyporphyrin) interface has been suggested when ZnO nanoparticles were doped in PVK. OLED studies have revealed that the photophysical characteristics and electrical behavior of devices with ZnO nanoparticles are much better than those of devices with pure PVK. The efficiency of devices based on [(Sm(III)] was superior than that of known aluminum tris(8-hydroxyquinoline) (Alq3) and also our earlier reports on red OLEDs under the same conditions.

A novel zinc finger protein Zfp277 mediates transcriptional repression of the Ink4a/arf locus through polycomb repressive complex 1

DEFF Research Database (Denmark)

Negishi, Masamitsu; Saraya, Atsunori; Mochizuki, Shinobu

2010-01-01

. METHODOLOGY/PRINCIPAL FINDINGS: We examined the function of Zinc finger domain-containing protein 277 (Zfp277), a novel zinc finger protein that interacts with the PcG protein Bmi1. Zfp277 binds to the Ink4a/Arf locus in a Bmi1-independent manner and interacts with polycomb repressor complex (PRC) 1 through...... is essential for the recruitment of PRC1 to the Ink4a/Arf locus. Our findings also highlight dynamic regulation of both Zfp277 and PcG proteins by the oxidative stress pathways....

Alumina/silica aerogel with zinc chloride as an alkylation catalyst

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DEJAN U. SKALA

2001-10-01

Full Text Available The alumina/silica with zinc chloride aerogel alkylation catalyst was obtained using a one step sol-gel synthesis, and subsequent drying with supercritical carbon dioxide. The aerogel catalyst activity was found to be higher compared to the corresponding xerogel catalyst, as a result of the higher aerogel surface area, total pore volume and favourable pore size distribution. Mixed Al–O–Si bonds were present in both gel catalyst types. Activation by thermal treatment in air was needed prior to catalytic alkylation, due to the presence of residual organic groups on the aerogel surface. The optimal activation temperature was found to be in the range 185–225°C, while higher temperatures resulted in the removal of zinc chloride from the surface of the aerogel catalyst with a consequential decrease in the catalytic activity. On varying the zinc chloride content, the catalytic activity of the aerogel catalyst exhibited a maximum. High zinc chloride contents decreased the catalytic activity of the aerogel catalyst as the result of the pores of the catalyst being plugged with this compound, and the separation of the alumina/silica support into Al-rich and Si-rich phases. The surface area, total pore volume, pore size distribution and zinc chloride content had a similar influence on the activity of the aerogel catalyst as was the case of xerogel catalyst and supported zinc chloride catalysts.

Synthesis and characterization of fly ash-zinc oxide nanocomposite

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Kunal Yeole

2014-04-01

Full Text Available Fly ash, generated in thermal power plants, is recognized as an environmental pollutant. Thus, measures are required to be undertaken to dispose it in an environmentally friendly method. In this paper an attempt is made to coat zinc oxide nano-particles on the surface of fly ash by a simple and environmentally friendly facile chemical method, at room temperature. Zinc oxide may serve as effective corrosion inhibitor by providing sacrificial protection. Concentration of fly ash was varied as 5, 10 and 15 (w/w % of zinc oxide. It was found that crystallinity increased, whereas particle size, specific gravity and oil absorption value decreased with increased concentration of fly ash in zinc oxide, which is attributed to the uniform distribution of zinc oxide on the surface of fly ash. These nanocomposites can potentially be used in commercial applications as additive for anticorrosion coatings.

Examination of Wetting by Liquid Zinc of Steel Sheets Following Various Kinds of Abrasive Blasting

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Cecotka M.

2016-06-01

Full Text Available Abrasive blasting is one of the methods of surface working before hot-dip zinc-coating. It allows not only to remove products of corrosion from the surface, but it also affects the quality of the zinc coating applied later, thereby affecting wettability of surface being zinc-coated. The surface working can be done with different types of abrasive material.

Zinc fixation preserves flow cytometry scatter and fluorescence parameters and allows simultaneous analysis of DNA content and synthesis, and intracellular and surface epitopes

DEFF Research Database (Denmark)

Jensen, Uffe Birk; Owens, David; Pedersen, Søren

2010-01-01

Zinc salt-based fixation (ZBF) has proved advantageous in histochemical analyses conducted on intact tissues but has not been exploited in flow cytometry procedures that focus on quantitative analysis of individual cells. Here, we show that ZBF performs equally well to paraformaldehyde in the pre......Zinc salt-based fixation (ZBF) has proved advantageous in histochemical analyses conducted on intact tissues but has not been exploited in flow cytometry procedures that focus on quantitative analysis of individual cells. Here, we show that ZBF performs equally well to paraformaldehyde...... allowing subsequent quantitative PCR analysis or labeling for incorporation of the thymidine analog EdU following surface and intracellular epitope staining. Finally, ZBF treatment allows for long-term storage of labeled cells with little change in these parameters. Thus, we present a protocol for zinc...... salt fixation of cells that allows for the simultaneous analysis of DNA and intracellular and cell surface proteins by flow cytometry....

Zinc Binding by Lactic Acid Bacteria

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Jasna Mrvčić

2009-01-01

Full Text Available Zinc is an essential trace element in all organisms. A common method for the prevention of zinc deficiency is pharmacological supplementation, especially in a highly available form of a metalloprotein complex. The potential of different microbes to bind essential and toxic heavy metals has recently been recognized. In this work, biosorption of zinc by lactic acid bacteria (LAB has been investigated. Specific LAB were assessed for their ability to bind zinc from a water solution. Significant amount of zinc ions was bound, and this binding was found to be LAB species-specific. Differences among the species in binding performance at a concentration range between 10–90 mg/L were evaluated with Langmuir model for biosorption. Binding of zinc was a fast process, strongly influenced by ionic strength, pH, biomass concentration, and temperature. The most effective metal-binding LAB species was Leuconostoc mesenteroides (27.10 mg of Zn2+ per gram of dry mass bound at pH=5 and 32 °C, during 24 h. FT-IR spectroscopy analysis and electron microscopy demonstrated that passive adsorption and active uptake of the zinc ions were involved.

Epitaxial growth of zinc on ferritic steel under high current density electroplating conditions

International Nuclear Information System (INIS)

Greul, Thomas; Comenda, Christian; Preis, Karl; Gerdenitsch, Johann; Sagl, Raffaela; Hassel, Achim Walter

2013-01-01

Highlights: •EBSD of electroplated Zn on Fe or steel was performed. •Zn grows epitaxially on electropolished ferritic steel following Burger's orientation relation. •Surface deformation of steel leads to multiple electroplated zinc grains with random orientation. •Zn grows epitaxially even on industrial surfaces with little surface deformation. •Multiple zinc grains on one steel grain can show identical orientation relations. -- Abstract: The dependence of the crystal orientation of electrodeposited zinc of the grain orientation on ferritic steel substrate at high current density deposition (400 mA cm −2 ) during a pulse-plating process was investigated by means of EBSD (electron backscatter diffraction) measurements. EBSD-mappings of surface and cross-sections were performed on samples with different surface preparations. Furthermore an industrial sample was investigated to compare lab-coated samples with the industrial process. The epitaxial growth of zinc is mainly dependent on the condition of the steel grains. Deformation of steel grains leads to random orientation while zinc grows epitaxially on non-deformed steel grains even on industrial surfaces

Room temperature Zinc-metallation of cationic porphyrin at graphene surface and enhanced photoelectrocatalytic activity

Science.gov (United States)

Zeng, Rongjin; Chen, Guoliang; Xiong, Chungang; Li, Gengxian; Zheng, Yinzhi; Chen, Jian; Long, Yunfei; Chen, Shu

2018-03-01

A stable zincporphyrin functionalized graphene nanocomposite was prepared by using positively charged cationic porphyrin (5,10,15,20-tetra(4-propyl pyridinio) porphyrin, TPPyP) and successive reduced graphene oxide (rGO) with tuned negative charge. The nanocomposite preparation was accompanied first by distinct electrostatic interactions and π-π stacking between TPPyP and rGO, and followed by fast Zinc-metallation at room temperature. In contrast to free TPPyP with Zn2+, the incorporation reaction is very slow at room temperature and heating or reflux conditions are required to increase the metallation rate. While at the surface of rGO nanosheet, the Zinc-metallation of TPPyP was greatly accelerated to 30 min at 25 °C in aqueous solution. The interaction process and composites formation were fully revealed by significant variations in UV-vis absorption spectra, X-ray photoelectron spectra (XPS) measurements, atomic force microscope (AFM) images, and fluorescence spectra. Furthermore, photoelectrochemical activity of resultant rGO/TPPyP-Zn nanocomposites was evaluated under visible-light irradiation, and enhancement of the photoelectrocatalytic reduction of CO2 was achieved.

THE METHOD OF ROLL SURFACE QUALITY MEASUREMENT FOR CONTINUOUS HOT DIP ZINC COATED STEEL SHEET PRODUCTION LINE

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Ki Yong Choi

2015-01-01

Full Text Available The present paper describes a developed analyzing system of roll surface during the process of continuous hot dip zinc coated steel sheet production line, in particular, adhering problem by transferred inclusions from roll to steel sheet surface during annealing process so called the pickup. The simulated test machine for coated roll surface in processing line has been designed and performed. The system makes it possible to analyze roll surface condition according to pickup phenomena from various roll coatings concerning operating conditions of hearth rolls in annealing furnace. The algorithm of fast pickup detection on surface is developed on the base of processing of several optical images of surface. The parameters for quality estimation of surface with pickups were developed. The optical system for images registration and image processing electronics may be used in real time and embed in processing line.

Antibacterial activity of zinc oxide-coated nanoporous alumina

Energy Technology Data Exchange (ETDEWEB)

Skoog, S.A. [Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Box 7115, Raleigh, NC 27695-7115 (United States); Bayati, M.R. [Department of Materials Science and Engineering, North Carolina State University, Box 7907, Raleigh, NC 27695-7907 (United States); Petrochenko, P.E. [Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Box 7115, Raleigh, NC 27695-7115 (United States); Division of Biology, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993 (United States); Stafslien, S.; Daniels, J.; Cilz, N. [Center for Nanoscale Science and Engineering, North Dakota State University, 1805 Research Park Drive, Fargo, ND 58102 (United States); Comstock, D.J.; Elam, J.W. [Energy Systems Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Narayan, R.J., E-mail: roger_narayan@msn.com [Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Box 7115, Raleigh, NC 27695-7115 (United States); Department of Materials Science and Engineering, North Carolina State University, Box 7907, Raleigh, NC 27695-7907 (United States)

2012-07-25

Highlights: Black-Right-Pointing-Pointer Atomic layer deposition was used to deposit ZnO on nanoporous alumina membranes. Black-Right-Pointing-Pointer Scanning electron microscopy showed continuous coatings of zinc oxide nanocrystals. Black-Right-Pointing-Pointer Activity against B. subtilis, E. coli, S. aureus, and S. epidermidis was shown. - Abstract: Nanoporous alumina membranes, also known as anodized aluminum oxide membranes, are being investigated for use in treatment of burn injuries and other skin wounds. In this study, atomic layer deposition was used for coating the surfaces of nanoporous alumina membranes with zinc oxide. Agar diffusion assays were used to show activity of zinc oxide-coated nanoporous alumina membranes against several bacteria found on the skin surface, including Bacillus subtilis, Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis. On the other hand, zinc oxide-coated nanoporous alumina membranes did not show activity against Pseudomonas aeruginosa, Enterococcus faecalis, and Candida albicans. These results suggest that zinc oxide-coated nanoporous alumina membranes have activity against some Gram-positive and Gram-negative bacteria that are associated with skin colonization and skin infection.

Potential interaction between zinc ions and a cyclodextrin-based diclofenac formulation.

Science.gov (United States)

Hamdan, Imad I; El-Sabawi, Dina; Abdel Jalil, Mariam

2016-03-01

Complexes of diclofenac sodium (DF-Na) with hydroxypropyl betacyclodextrin (HPβCD) were prepared by co-evaporation in a 1:1 ratio and characterized in light of previously reported data. Phase solubility diagrams were obtained for DF-Na with HPβCD in the presence and absence of zinc ions. Dissolution profiles were obtained for DF-Na and its HPβCD complex at acidic (pH 1.2) as well as in phosphate buffer (pH 6.8), in the presence and absence of zinc. HPβCD, as expected, was shown to improve the dissolution of DF-Na in acidic medium but not in phosphate buffer (pH 6.8). The presence of zinc ions decreased the in vitro dissolution of DF-HPβCD complex in acidic medium (pH 1.2) but not in phosphate buffer (pH 6.8). It was confirmed that the precipitate that was formed by zinc ions in the presence of HPβCD and DF-Na contained no cyclodextrin and most likely it was a mixture of the complexes: DF 2 -Zn and DF-Zn with some molecules of water. In vivo experiments on rats have shown that HPβCD has no statistically significant effect on absorption or bioavailability of DF-Na in spite of the observed improvement of its in vitro dissolution by HPβCD. Moreover, zinc ions were shown to decrease the absorption rate of DF-Na in rats model but did neither significantly alter the absorption nor bioavailability of DF-HPβCD complex. The zinc induced precipitates of DF were shown to have significantly different crystalline properties when HPβCD was present. Therefore, the pharmaceutical details of a DF-Na preparation should be considered when designing the formulation and predicting possible interaction between DF-Na (or other potential NSAIDs) and zinc metal.

Hydrogen-related complexes in Li-diffused ZnO single crystals

Energy Technology Data Exchange (ETDEWEB)

Corolewski, Caleb D. [Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164-2814 (United States); Parmar, Narendra S.; Lynn, Kelvin G. [Center for Materials Research, Washington State University, Pullman, Washington 99164-2814 (United States); McCluskey, Matthew D., E-mail: mattmcc@wsu.edu [Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164-2814 (United States); Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164-2814 (United States)

2016-07-21

Zinc oxide (ZnO) is a wide band gap semiconductor and a potential candidate for next generation white solid state lighting applications. In this work, hydrogen-related complexes in lithium diffused ZnO single crystals were studied. In addition to the well-known Li-OH complex, several other hydrogen defects were observed. When a mixture of Li{sub 2}O and ZnO is used as the dopant source, zinc vacancies are suppressed and the bulk Li concentration is very high (>10{sup 19 }cm{sup −3}). In that case, the predominant hydrogen complex has a vibrational frequency of 3677 cm{sup −1}, attributed to surface O-H species. When Li{sub 2}CO{sub 3} is used, a structured blue luminescence band and O-H mode at 3327 cm{sup −1} are observed at 10 K. These observations, along with positron annihilation measurements, suggest a zinc vacancy–hydrogen complex, with an acceptor level ∼0.3 eV above the valence-band maximum. This relatively shallow acceptor could be beneficial for p-type ZnO.

Biologically-transformed zinc and its availability for bioaccumulation by marine organisms

International Nuclear Information System (INIS)

Fowler, S.W.; Heyraud, M.

1980-01-01

Zinc which occurs in sea water as a trace element exists in several different stable or meta-stable forms in the aquatic environment. One of them is ''complexed'' form which is relatively stable. Radiotracer studies were carried out to investigate the mode of formation of the complexed zinc fraction and to find whether this fraction once formed by biological means is available for accumulation by marine biota. Sea water solutions used in the experiments were filtered through double 0.45 μm Millipore filters. Chelex-100 resin which quantitatively removes zinc from sea water was used to measure the relative degree of binding of different species of 65 Zn formed by association with marine organisms. 65 Zn in exometabolites from living animals represented in this case by shrimp (Lymata seticaudata), influence of organic detritus represented in this case by dead shrimp on the conversion of different forms of zinc and bioavailability of biologically processed 65 Zn were studied. It was observed that: (1) living and dead marine animals can produce a soluble species of complexed, possibly organically bound, zinc, (2) uptake of this species is reduced relative to that of the ionic form indicating that zinc which has passed through biological cycles may be less available for bioaccumulation than zinc which has been directly introduced into the marine environment in inorganic forms. (M.G.B.)

Status of zinc injection in PWRs

Energy Technology Data Exchange (ETDEWEB)

Bergmann, C.A. [Westinghouse Electric Co., Pittsburgh, PA (United States)

1995-03-01

Based on laboratory and other studies, it was concluded that zinc addition in a PWR primary coolant should result in reduced Alloy 600 PWSCC and general corrosion rates of the materials of construction. Because of these positive results, a Westinghouse Owner`s Subgroup, EPRI, and Westinghouse provided funds to continue the development and application of zinc in an operating plant. As part of the program, Southern Operating Nuclear Company agreed to operate the Farley 2 plant with zinc addition as a demonstration test of the effectiveness of zinc. Since zinc is incorporated in the corrosion oxide film on the primary system surfaces and Farley 2 is a mature plant, it was estimated that about 10 kgs of zinc would be needed to condition the plant before an equilibrium value in the coolant would be reached. The engineered aspects of a Zinc Addition and Monitoring System (ZAMS) considered such items as the constitutents, location, sizing and water supply of the ZAMS. Baseline data such as the PWSCC history of the Alloy 600 steam generator tubing, fuel oxide thickness, fuel crud deposits, radiation levels, and RCP seal leak-off rates were obtained before zinc addition is initiated. This presentation summarizes some of the work performed under the program, and the status of zinc injection in the Farley 2 plant.

Resistance of extremely halophilic archaea to zinc and zinc oxide nanoparticles

Science.gov (United States)

Salgaonkar, Bhakti B.; Das, Deepthi; Bragança, Judith Maria

2016-02-01

Industrialization as well as other anthropogenic activities have resulted in addition of high loads of metal and/or metal nanoparticles to the environment. In this study, the effect of one of the widely used heavy metal, zinc (Zn) and zinc oxide nanoparticles (ZnO NPs) on extremely halophilic archaea was evaluated. One representative member from four genera namely Halococcus, Haloferax, Halorubrum and Haloarcula of the family Halobacteriaceae was taken as the model organism. All the haloarchaeal genera investigated were resistant to both ZnCl2 and ZnO NPs at varying concentrations. Halococcus strain BK6 and Haloferax strain BBK2 showed the highest resistance in complex/minimal medium of up to 2.0/1.0 mM ZnCl2 and 2.0/1.0-0.5 mM ZnO NP. Accumulation of ZnCl2/ZnO NPs was seen as Haloferax strain BBK2 (287.2/549.6 mg g-1) > Halococcus strain BK6 (165.9/388.5 mg g-1) > Haloarcula strain BS2 (93.2/28.5 mg g-1) > Halorubrum strain BS17 (29.9/16.2 mg g-1). Scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDX) analysis revealed that bulk ZnCl2 was sorbed at a higher concentration (21.77 %) on the cell surface of Haloferax strain BBK2 as compared to the ZnO NPs (14.89 %).

Surface plasmon resonance based fiber optic detection of chlorine utilizing polyvinylpyrolidone supported zinc oxide thin films.

Science.gov (United States)

Tabassum, Rana; Gupta, Banshi D

2015-03-21

A highly sensitive chlorine sensor for an aqueous medium is fabricated using an optical fiber surface plasmon resonance (OFSPR) system. An OFSPR-based chlorine sensor is designed with a multilayer-type platform by zinc oxide (ZnO) and polyvinylpyrollidone (PVP) film morphology manipulations. Among all the methodologies of transduction reported in the field of solid state chemical and biochemical sensing, our attention is focused on the Kretschmann configuration optical fiber sensing technique using the mechanism of surface plasmon resonance. The optical fiber surface plasmon resonance (SPR) chlorine sensor is developed using a multimode optical fiber with the PVP-supported ZnO film deposited over a silver-coated unclad core of the fiber. A spectral interrogation mode of operation is used to characterize the sensor. In an Ag/ZnO/PVP multilayer system, the absorption of chlorine in the vicinity of the sensing region is performed by the PVP layer and the zinc oxide layer enhances the shift in resonance wavelength. It is, experimentally, demonstrated that the SPR wavelength shifts nonlinearly towards the red side of the visible region with an increase in the chlorine concentration in an aqueous medium while the sensitivity of the sensor decreases linearly with an increase in the chlorine concentration. As the proposed sensor utilizes an optical fiber, it possesses the additional advantages of fiber such as less signal degradation, less susceptibility to electromagnetic interference, possibility of remote sensing, probe miniaturization, probe re-usability, online monitoring, small size, light weight and low cost.

PIXE characterization of by-products resulting from the zinc recycling of industrial cemented carbides

International Nuclear Information System (INIS)

Freemantle, C.S.; Sacks, N.; Topic, M.; Pineda-Vargas, C.A.

2015-01-01

By-product materials of the widely used zinc recycling process of cemented carbides have been studied. Scanning electron microscopy and micro-PIXE techniques have identified elemental concentrations, distributions and purity of by-product materials from an industrial zinc recycling plant. Cobalt surface enrichment, lamellar microstructures of varying composition, including alternating tungsten carbide (WC) grains and globular cobalt, and regions of excess zinc contamination were found in materials with incomplete zinc penetration. Liquid Co–Zn formation occurred above 72 wt.% Zn at the furnace temperature of 930 °C, and was extracted towards the surface of poorly zinc infiltrated material, primarily by the vacuum used for zinc distillation. Surface enrichment was not observed in material that was zinc infiltrated to the sample center, which was more friable and exhibited more homogeneous porosity and elemental concentrations. The result of incomplete zinc infiltration was an enriched surface zone of up to 60 wt.% Co, compared to an original sample composition of ∼10–15 wt.% Co. The impact on resulting powders could be higher or inhomogeneous cobalt content, as well as unacceptably high zinc concentrations. PIXE has proven it can be a powerful technique for solving industrial problems in the cemented carbide cutting tool industry, by identifying trace elements and their locations (such as Zn to 0.1 wt.% accuracy), as well as the distribution of major elements within WC–Co materials.

PIXE characterization of by-products resulting from the zinc recycling of industrial cemented carbides

Energy Technology Data Exchange (ETDEWEB)

Freemantle, C.S. [School of Chemical & Metallurgical Engineering and DST-NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, P/Bag 3, Wits 2050 (South Africa); Pilot Tools (Pty) (Ltd), P.O. Box 27420, Benrose 2011 (South Africa); Sacks, N. [School of Chemical & Metallurgical Engineering and DST-NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, P/Bag 3, Wits 2050 (South Africa); Topic, M. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Pineda-Vargas, C.A. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Faculty of Health & Wellness Sciences, CPUT, Bellville (South Africa)

2015-11-15

By-product materials of the widely used zinc recycling process of cemented carbides have been studied. Scanning electron microscopy and micro-PIXE techniques have identified elemental concentrations, distributions and purity of by-product materials from an industrial zinc recycling plant. Cobalt surface enrichment, lamellar microstructures of varying composition, including alternating tungsten carbide (WC) grains and globular cobalt, and regions of excess zinc contamination were found in materials with incomplete zinc penetration. Liquid Co–Zn formation occurred above 72 wt.% Zn at the furnace temperature of 930 °C, and was extracted towards the surface of poorly zinc infiltrated material, primarily by the vacuum used for zinc distillation. Surface enrichment was not observed in material that was zinc infiltrated to the sample center, which was more friable and exhibited more homogeneous porosity and elemental concentrations. The result of incomplete zinc infiltration was an enriched surface zone of up to 60 wt.% Co, compared to an original sample composition of ∼10–15 wt.% Co. The impact on resulting powders could be higher or inhomogeneous cobalt content, as well as unacceptably high zinc concentrations. PIXE has proven it can be a powerful technique for solving industrial problems in the cemented carbide cutting tool industry, by identifying trace elements and their locations (such as Zn to 0.1 wt.% accuracy), as well as the distribution of major elements within WC–Co materials.

Zinc-zincate electrochemical behaviour in NaOH medium

International Nuclear Information System (INIS)

Pessine, E.J.

1984-01-01

The reaction mechanism of zinc/NaOH-zincate system was investigated with the rotating disk electrode technique, using both the surfaces of mercury film and zinc in 1M NaOH concentration and 25 0 C temperature. It was found that, at the mercury surface, the zincate ion deposition reaction occurs by two steps with one electron each, with comparable rates, with b sup(-) sub(K1) = (132+ -20)mV/decade and b sup(-) sub(K2) = (74 + - 9)mV/decade cathodic Tafel slopes. At the zinc surface the mechanism of the anodic and cathodic reactions is the same and is by two steps with one electron each. The rate-determining step is the first reaction in the cathodic direction. The exchange current density was found to be between 1.00 and 6.00mA/cm 2 , with b sup(-) sub(K) = (95+ -3)mV/decade cathodic and b sup(-) sub(a) = (61+ -5)mV/decade anodic Tafel slopes. The mechanism of passivation of zinc occurs as a result of the two reactions, the adsorption of the dissolved species of zinc II and the precipitation of the zincate ions over the electrode active sites. It has been verified that of all the chemical species studied namely the zincate, chloride, benzoate, silicate ions and the benzotriazole that affect the zinc anodic reaction the silicate ion is the one that change the reaction rate. However, for all the species studied we have the same anodic reaction mechanism (active dissolution). The deposition reaction mechanism of the zincate ion on zinc electrode is the same with NaOH plus benzoate or chloride. The diffusion coefficient found for the diffusion of the zincate ion in 1M NaOH with the mercury film RDE is D sup(-) = (4,90+ -0,20) x 10 -6 cm 2 s -1 . (Author) [pt

Radiation induced traps of zinc phosphate and phosphide

International Nuclear Information System (INIS)

Murali, K.R.; Rao, D.R.

1980-01-01

Thermoluminescence (TL) glow curve (TGC) method has been used to study the traps produced by X-irradiation in Zn 3 (PO 4 ) 2 and Zn 3 P 2 . Prominent TL glow peaks were observed at 100 0 and 360 0 C for zinc phosphate while for zinc phosphide only one glow peak at 245 0 C was observed, and in the latter case the TL output was in general quite low compared to zinc phosphate. The TL spectra for both the glow peaks of zinc phosphate indicated emission band in the region around 560 nm, while for zinc phosphide the emission occurred at 575 nm (in the temperature region 200-270 0 C). The low temperature glow peaks below 270 0 C were less stable compared to those above 300 0 C and were completely destroyed when the irradiated samples were stored in darkness for 24 hr at room temperature. Shining by 470 nm light however produced preferential bleaching of the two TL peaks at 100 and 360 0 C with no effect on the 245 0 C glow peak of zinc phosphide. It is concluded that during heat treatment large numbers of Zn-vacancies are formed due to which complexes like Zn-P are produced by irradiation and the TL traps destroyed in a radiative recombination process are related with these complexes. (author)

Holographic subregion complexity for singular surfaces

Energy Technology Data Exchange (ETDEWEB)

Bakhshaei, Elaheh [Isfahan University of Technology, Department of Physics, Isfahan (Iran, Islamic Republic of); Mollabashi, Ali [Institute for Research in Fundamental Sciences (IPM), School of Physics, Tehran (Iran, Islamic Republic of); Shirzad, Ahmad [Isfahan University of Technology, Department of Physics, Isfahan (Iran, Islamic Republic of); Institute for Research in Fundamental Sciences (IPM), School of Particles and Accelerators, Tehran (Iran, Islamic Republic of)

2017-10-15

Recently holographic prescriptions were proposed to compute the quantum complexity of a given state in the boundary theory. A specific proposal known as 'holographic subregion complexity' is supposed to calculate the complexity of a reduced density matrix corresponding to a static subregion. We study different families of singular subregions in the dual field theory and find the divergence structure and universal terms of holographic subregion complexity for these singular surfaces. We find that there are new universal terms, logarithmic in the UV cut-off, due to the singularities of a family of surfaces including a kink in (2 + 1) dimensions and cones in even dimensional field theories. We also find examples of new divergent terms such as squared logarithm and negative powers times the logarithm of the UV cut-off parameter. (orig.)

Symptomatic zinc deficiency in experimental zinc deprivation.

OpenAIRE

Taylor, C M; Goode, H F; Aggett, P J; Bremner, I; Walker, B E; Kelleher, J

1992-01-01

An evaluation of indices of poor zinc status was undertaken in five male subjects in whom dietary zinc intake was reduced from 85 mumol d-1 in an initial phase of the study to 14 mumol d-1. One of the subjects developed features consistent with zinc deficiency after receiving the low zinc diet for 12 days. These features included retroauricular acneform macullo-papular lesions on the face, neck, and shoulders and reductions in plasma zinc, red blood cell zinc, neutrophil zinc and plasma alkal...

Zinc(II) complexes with intramolecular amide oxygen coordination as models of metalloamidases.

Science.gov (United States)

Rivas, Juan C Mareque; Salvagni, Emiliano; Prabaharan, Ravi; de Rosales, Rafael Torres Martin; Parsons, Simon

2004-01-07

Polydentate ligands (6-R1-2-pyridylmethyl)-R2(R1= NHCOtBu, R2= bis(2-pyridylmethyl)amine L1, bis(2-(methylthio)ethyl)amine L2 and N(CH2CH2)2S L3) form mononuclear zinc(II) complexes with intramolecular amide oxygen coordination and a range of coordination environments. Thus, the reaction of Zn(ClO4)2.6H2O with L1-3 in acetonitrile affords [(L)Zn](ClO4)2(L=L1, 1; L2, 2) and [(L3)Zn(H2O)(NCCH3)](ClO4)2 3. The simultaneous amide/water binding in resembles the motif that has been proposed to be involved in the double substrate/nucleophile Lewis acidic activation and positioning mechanism of amide bond hydrolysis in metallopeptidases. X-ray diffraction, 1H and 13C NMR and IR data suggests that the strength of amide oxygen coordination follows the trend 1>2 >3. L1-3 and undergo cleavage of the tert-butylamide upon addition of Me4NOH.5H2O (1 equiv.) in methanol at 50(1)degrees C. The rate of amide cleavage follows the order 1> 2> 3, L1-3. The extent by which the amide cleavage reaction is accelerated in 1-3 relative to the free ligands, L1-3, is correlated with the strength of amide oxygen binding and Lewis acidity of the zinc(II) centre in deduced from the X-ray, NMR and IR studies.

Cathodic protection of steel by electrodeposited zinc-nickel alloy coatings

Energy Technology Data Exchange (ETDEWEB)

Baldwin, K.R.; Smith, C.J.E. [Defence Research Agency, Farnborough (United Kingdom). Structural Materials Centre; Robinson, M.J. [Cranfield Univ. (United Kingdom). School of Industrial and Manufacturing Science

1995-12-01

The ability of electrodeposited zinc-nickel alloy coatings to cathodically protect steel was studied in dilute chloride solutions. The potential distribution along steel strips partly electroplated with zinc-nickel alloys was determined, and the length of exposed steel that was held below the minimum protection potential (E{sub prot}) was taken as a measure of the level of cathodic protection (CP) provided by the alloy coatings. The level of CP afforded by zinc alloy coatings was found to decrease with increasing nickel content. When nickel content was increased to {approx} {ge} 21 wt%, no CP was obtained. Surface analysis of uncoupled zinc-nickel alloys that were immersed in sodium chloride (NaCl) solutions showed the concentration of zinc decreased in the surface layers while the concentration of nickel increased, indicating that the alloys were susceptible to dezincification. The analysis of zinc-nickel alloy coatings on partly electroplated steel strips that were immersed in chloride solution showed a significantly higher level of dezincification than that found for uncoupled alloy coatings. This effect accounted for the rapid loss of CP afforded to steel by some zinc alloy coatings, particularly those with high initial nickel levels.

Intensification of zinc dissolution process in sulphuric acid

Directory of Open Access Journals (Sweden)

Stanojević D.

2005-01-01

Full Text Available Many high purity salts are produced by dissolving pure metal in non-oxidizing mineral acids. If hydrogen overpotential on the given metal is high, then the rate of overall process is defined by reaction of hydrogen ion reduction. This study investigated the possibility of accelerated dissolving of metal zinc in sulphuric acid by introducing copper cathode on which evolving hydrogen is much easier than on zinc. It was found out that the acceleration of zinc dissolving is possible and, at constant surface of copper cathode depends on the quality of electrical contact between copper electrode and zinc.

Zinc Finger Takes on a Whole New Meaning: Reducing and Monitoring Zinc Blanks in the Isotope Lab

Science.gov (United States)

Wilkes, E. B.; Wasylenki, L. E.; Anbar, A. D.

2010-12-01

In terms of avoiding contamination, zinc is one of the most difficult elements to study isotopically. The reason for this is that zinc stearate is a very common mold release agent in the production of plastics, including those most often used in isotope geochemistry clean labs. While polyethylene bottles, polypropylene centrifuge tubes, pipette tips, and Kimwipes are all potential sources of contaminant zinc, by far the largest amount of zinc is introduced to the laboratory by gloves. Most items can be effectively rid of zinc by soaking in dilute hydrochloric acid, but gloves cannot be cleaned easily, and use of gloves can quickly lead to contamination on many surfaces throughout the lab. We recently conducted several experiments in which dissolved zinc was partly adsorbed onto synthetic Mn oxyhydroxide particles. The dissolved and adsorbed pools were separated by filtration, purified with ion exchange chemistry, and analyzed for isotope composition by MC-ICP-MS. We used a commercially purchased ICP standard solution both as our standard (delta66/64Zn = 0) and as the source of the zinc in the experiments. Whenever gloves were worn during purification, process blanks contained as much as 150 ng Zn, and both the dissolved and adsorbed pools of zinc came out enriched in heavy isotopes relative to the starting pool, contrary to our expectation of mass balance. When gloves were not worn, blanks were brands of vinyl gloves, including one brand recommended to us for being “low” in zinc, measured +10‰ relative to our standard. We therefore concluded that glove zinc contaminated most of our experimental samples. We were only able to see such clear evidence of contamination because (1) we were doing an experiment in which we expected one light and one heavy pool of zinc compared to our standard, and (2) we happened to use an ICP standard solution for delta = 0 that is strongly enriched in light isotopes relative to both brands of gloves. We caution others who measure

BWR radiation buildup control with ionic zinc

International Nuclear Information System (INIS)

Marble, W.J.; Wood, C.J.; Leighty, C.E.; Green, T.A.

1986-01-01

In 1983 a hypothesis was disclosed which suggested that the presence of ionic zinc in the reactor water of the BWR could reduce radiation buildup. This hypothesis was developed from correlations of plant data, and subsequently, from laboratory experiments which demonstrated clearly that ionic zinc inhibits the corrosion of stainless steel. The benefits of zinc addition have been measured at the Vallecitos Nuclear Center under and EPRI/GE project. Experimentation and analyses have been performed to evaluate the impact of intentional zinc addition on the IGSCC characteristics of primary system materials and on the performance of the nuclear fuel. It has been concluded that no negative effects are expected. The author conclude that the intentional addition of ionic zinc to the BWR reactor water at a concentration of approximately 10 ppb will provide major benefits in controlling the Co-60 buildup on primary system stainless steel surfaces. The intentional addition of zinc is now a qualified technique for use in BWRs

Adsorption of the diazo dye Direct Red 23 onto a zinc oxide surface: A spectroscopic study

Science.gov (United States)

Lucilha, Adriana Campano; Bonancêa, Carlos Eduardo; Barreto, Wagner José; Takashima, Keiko

2010-01-01

The adsorption of the diazo dye Direct Red 23 onto a zinc oxide surface at 30 °C in the dark was investigated. The color reduction was monitored by spectrophotometry at 503 nm. The FTIR and Raman spectra of the Direct Red 23 adsorption as a function of ZnO concentration were registered. From the PM3 semi-empirical calculations of the atomic charge density and dipole moment of the Direct Red 23 molecule, it was demonstrated that the azo dye molecule may be adsorbed onto the ZnO surface through molecule geometry modifications, enhancing the interfacial area causing a variation in the bonding frequencies.

Zinc composite anode for batteries with solid electrolyte

Science.gov (United States)

Tedjar, F.; Melki, T.; Zerroual, L.

A new negative composite anode for batteries with a solid electrolyte is studied. Using a complex of zinc ammonium chloride mixed with zinc metal powder, the advantage of the Zn/Zn 2+ electrode ( e = -760 mV) is kept while the energy density and the shelf-life of the battery are increased.

Diagnostic study of the roughness surface effect of zirconium on the third-order nonlinear-optical properties of thin films based on zinc oxide nanomaterials

International Nuclear Information System (INIS)

Bahedi, K.; Addou, M.; El Jouad, M.; Sofiani, Z.; Alaoui Lamrani, M.; El Habbani, T.; Fellahi, N.; Bayoud, S.; Dghoughi, L.; Sahraoui, B.; Essaidi, Z.

2009-01-01

Zinc oxide (ZnO) and zirconium doped zinc oxide (ZnO:Zr) thin films were deposited by reactive chemical pulverization spray pyrolysis technique on heated glass substrates at 500 deg. C using zinc and zirconium chlorides as precursors. Effects of zirconium doping agent and surface roughness on the nonlinear optical properties were investigated in detail using atomic force microscopy (AFM) and third harmonic generation (THG) technique. The best value of nonlinear optical susceptibility χ (3) was obtained from the doped films with less roughness. A strong third order nonlinear optical susceptibility χ (3) = 20.12 x 10 -12 (esu) of the studied films was found for the 3% doped sample.

Photocatalysis application of zinc oxide fibers obtained by electrospinning

International Nuclear Information System (INIS)

Gerchman, D.; Alves, A.K.; Berutti, F.A.; Bergmann, C.P.

2010-01-01

Using the electrospinning technique, composite fibers of polyvinylbutyral and zinc nitrate were obtained. After a heat treatment at 600 deg C, nanostructured zinc oxide fibers were obtained. The fibers were characterized using X ray diffraction. The photocatalytic activity of the nanostructured fibers was determined using the photodegradation of a methyl orange solution. The increase in the heat treatment temperature decreases the photoactivity of the zinc oxide. The heat treatment, the phases and the surface area, affect the physical, chemical and photocatalytic activity of the zinc oxide. (author)

Zinc injection helps reduce radiation field buildup in BWRs

International Nuclear Information System (INIS)

Wood, C.

1991-01-01

The injection of zinc into the reactor water of BWRs (Boiling Water Reactors) was a technique developed by General Electric (GE) and the Electric Power Research Institute (EPRI) to control the buildup of radiation fields from cobalt-60 on out-of-core piping. The presence of 5-10ppb zinc in the reactor water reduces the growth of oxide films on stainless steel surfaces, thereby reducing the number of sites available for the incorporation of cobalt; zinc also competes with cobalt for the sites. In September 1990, EPRI organized a workshop at the request of several US utilities to provide a forum to discuss experiences with zinc injection. The meeting focused on six main issues: the effect of zinc on radiation fields in normal water chemistry; the radiation buildup in hydrogen water chemistry, with and without zinc; the effects of zinc-65; the corrosion of fuel cladding and structural materials; the performance of zinc injection and monitoring equipment; and planning for zinc injection. (author)

Ultrafast pump-probe spectroscopy of Zinc Phthalocynine (ZnPc) and light harvesting complex II (LHC II)

CSIR Research Space (South Africa)

Ombinda-Lemboumba, Saturnin

2009-07-01

Full Text Available pump-probe spectroscopy of Zinc Phthalocynine (ZnPc) and light harvesting complex II (LHC II) SAIP 7-10 July 2009, University of Kwazulu Natal. S. Ombinda-Lemboumba1, 2 A. du Plessis1, L. Botha1, D.E. Roberts1, P. Molukanele1, 3, R.W. Sparrow3, E... and phtobiology (2008) Page 12 Conclusion SAIP 7-10 July 2009, University of Kwazulu natal Femto group © CSIR 2008 www.csir.co.za • Presented our method of correcting chirp induced by white light generation. • Pump...

Corrosion and solubility in a TSP-buffered chemical environment following a loss of coolant accident: Part 2 – Zinc

International Nuclear Information System (INIS)

Pease, David; LaBrier, Daniel; Ali, Amir; Blandford, Edward D.; Howe, Kerry J.

2016-01-01

Highlights: • Zinc release is limited to less than 1 mg/L in TSP-buffered solution under a variety of conditions (pH, temperature, zinc source). • Zinc release in high-temperature non-TSP-buffered environment is approximately 25 mg/L. • Long-term zinc release is controlled by passivation (without TSP) and zinc solubility (with TSP). • Precipitation and solubility of zinc phosphate limit the release of zinc. - Abstract: Bench experiments were conducted to investigate the effect of the presence of trisodium phosphate (TSP) on the corrosion and release of zinc from metallic zinc-bearing surfaces under conditions representative of the containment pool following a postulated loss of coolant accident (LOCA) at a nuclear power generating facility. The experiments showed that in non-buffered (acidic) environments, measurable quantities of zinc are released from zinc-bearing surfaces. Precipitation and solubility of phosphate-based corrosion products, such as zinc phosphate, limit the release of zinc from zinc-bearing surfaces. These experiments have found that under a variety of conditions, including variations of temperature, pH, and across different zinc-bearing surfaces, the release of zinc into solution is limited to <1 mg/L when phosphate is present. When phosphate is not present, zinc release is instead bounded by a markedly higher saturation limit which is a strong function of the solution temperature.

Organically complexed copper, zinc, and chelating agents in the rivers of Western Puerto Rico

International Nuclear Information System (INIS)

Montgomery, J.R.; Echevarria, J.E.

1975-01-01

The method for determining soluble chelators gives their concentration in copper-equivalent chelating capacity units in fresh or slightly brackish (less than 3 percent salinity) water. The mean concentration of chelators in the Rio Guanajibo for December 1973 and January 1974 was 0.4 mg of copper per liter of water (N = 21, SD = 0.2) and for February 1974, 0.9 mg/liter (N = 8, SD = 0.4). The combined mean for the Rio Anasco and Culebrinas was 0.5 mg/liter (N = 7, SD = 0.4) in January and February 1974. The mean concentration of ionic copper was 0.5 μg/liter (N = 7, SD = 0.6) and of ionic zinc, 0.2 μg/liter (N = 8, SD = 0.1) in the Rio Guanajibo from November 1972 to February 1973. The concentration of organically bound copper was 0.3 μ/liter (N = 7, SD = 0.2) and that of organically bound zinc was 0.6 μg/liter (N = 8, SD = 0.6); this indicates that there was more than a sufficient quantity of chelator available in the river to complex all the soluble copper. The presence of a high ratio of Ca 2+ to Cu 2+ probably prevents the formation of larger concentrations of organically complexed copper. The mean concentration of chelating agents in the Guanajibo River seems to be directly related to the increased organic input from municipalities and a sugar mill. The concentration of chelators in tropical rivers appears to be higher than that found in Canadian lakes. The mean concentration for particulate organic carbon (POC) was 3653 μg atoms/liter (SD = 3653, N = 29). The dissolved reactive phosphate (DRP) ranged from a mean of 1.1 μg atom/liter. No significant correlation could be found between POC, DRP, and the concentration of chelators

Comparisons of the spectroscopic and microbiological activities among coumarin-3-carboxylate, o-phenanthroline and zinc(II) complexes

Science.gov (United States)

Islas, María S.; Martínez Medina, Juan J.; Piro, Oscar E.; Echeverría, Gustavo A.; Ferrer, Evelina G.; Williams, Patricia A. M.

2018-06-01

Coumarins (2H-chromen-2-one) are oxygen-containing heterocyclic compounds that belong to the benzopyranones family. In this work we have synthesized different coordination complexes with coumarin-3-carboxylic acid (HCCA), o-phenanthroline (phen) and zinc(II). In the reported [Zn(CCA)2(H2O)2] complex, coumarin-3-carboxylate (CCA) is acting as a bidentate ligand while in the two prepared complexes, [Zn(phen)3]CCA(NO3) (obtained as a single crystal) and [Zn(CCA)2phen].4H2O, CCA is acting as a counterion of the complex cation [Zn(phen)3]+2 or coordinated to the metal center along with phen, respectively. These compounds were characterized on the basis of elemental analysis and thermogravimetry. NMR, FTIR and Raman spectroscopies of the compounds and the CCA potassium salt (KCCA) allow to determine several similarities and differences among them. Finally, their behavior against alkaline phosphatase enzyme and their antimicrobial activities were also measured.

Evaluation of Zinc solubilization potential by different strains of ...

African Journals Online (AJOL)

Michael Horsfall

the colony diameter and area respectively for zinc oxide and zinc carbonate were as following, respectively: 0.60-. 1.32 cm, 1.20-2.64 ... the formation of highly insoluble metal sulphide .... from microorganisms to the surface of minerals, and.

Zinc

Science.gov (United States)

... Consumer Datos en español Health Professional Other Resources Zinc Fact Sheet for Consumers Have a question? Ask ... find out more about zinc? Disclaimer What is zinc and what does it do? Zinc is a ...

Zinc composite anode for batteries with solid electrolyte

Energy Technology Data Exchange (ETDEWEB)

Tedjar, F.; Melki, T.; Zerroual, L. (Setif Univ. (Algeria). Unite de Recherche Electrochimie)

1992-05-01

A new negative composite anode for batteries with a solid electrolyte is studied. Using a complex of zinc ammonium chloride mixed with zinc metal powder, the advantage of the Zn/Zn[sup 2+] electrode (e = -760 mV) is kept while the energy density and the shelf-life of the battery are increased. (orig.).

Uncertainty analysis of point-by-point sampling complex surfaces using touch probe CMMs DOE for complex surfaces verification with CMM

DEFF Research Database (Denmark)

Barini, Emanuele Modesto; Tosello, Guido; De Chiffre, Leonardo

2010-01-01

The paper describes a study concerning point-by-point sampling of complex surfaces using tactile CMMs. A four factor, two level completely randomized factorial experiment was carried out, involving measurements on a complex surface configuration item comprising a sphere, a cylinder and a cone, co...

Electronic Structure of the Perylene / Zinc Oxide Interface: A Computational Study of Photoinduced Electron Transfer and Impact of Surface Defects

KAUST Repository

Li, Jingrui

2015-07-29

The electronic properties of dye-sensitized semiconductor surfaces consisting of pery- lene chromophores chemisorbed on zinc oxide via different spacer-anchor groups, have been studied at the density-functional-theory level. The energy distributions of the donor states and the rates of photoinduced electron transfer from dye to surface are predicted. We evaluate in particular the impact of saturated versus unsaturated aliphatic spacer groups inserted between the perylene chromophore and the semiconductor as well as the influence of surface defects on the electron-injection rates.

Electronic Structure of the Perylene / Zinc Oxide Interface: A Computational Study of Photoinduced Electron Transfer and Impact of Surface Defects

KAUST Repository

Li, Jingrui; Li, Hong; Winget, Paul; Bredas, Jean-Luc

2015-01-01

The electronic properties of dye-sensitized semiconductor surfaces consisting of pery- lene chromophores chemisorbed on zinc oxide via different spacer-anchor groups, have been studied at the density-functional-theory level. The energy distributions of the donor states and the rates of photoinduced electron transfer from dye to surface are predicted. We evaluate in particular the impact of saturated versus unsaturated aliphatic spacer groups inserted between the perylene chromophore and the semiconductor as well as the influence of surface defects on the electron-injection rates.

Electrical conductivity of chromate conversion coating on electrodeposited zinc

International Nuclear Information System (INIS)

Tencer, Michal

2006-01-01

For certain applications of galvanized steel protected with conversion coatings it is important that the surface is electrically conductive. This is especially important with mating surfaces for electromagnetic compatibility. This paper addresses electrical conductivity of chromate conversion coatings. A cross-matrix study using different zinc plating techniques by different labs showed that the main deciding factor is the type of zinc-plating bath used rather than the subsequent chromating process. Thus, chromated zinc plate electrodeposited from cyanide baths is non-conductive while that from alkaline (non-cyanide) and acid baths is conductive, even though the plate from all the bath types is conductive before conversion coating. The results correlate well with the microscopic structure of the surfaces as observed with scanning electron microscopy (SEM) and could be further corroborated and rationalized using EDX and Auger spectroscopies

Zinc(II) complexes with potent cyclin-dependent kinase inhibitors derived from 6-benzylaminopurine: synthesis, characterization, X-ray structures and biological activity

Czech Academy of Sciences Publication Activity Database

Trávníček, Zdeněk; Kryštof, Vladimír; Šipl, M.

2006-01-01

Roč. 100, č. 2 (2006), s. 214-225 ISSN 0162-0134 R&D Projects: GA ČR GA203/04/1168 Institutional research plan: CEZ:AV0Z50380511 Keywords : Zinc(II) complexes * 6-Benzylaminopurine derivatives * Bohemine * Olomoucine * X-ray structures Subject RIV: CA - Inorganic Chemistry Impact factor: 2.654, year: 2006

Zinc-based electrolyte compositions, and related electrochemical processes and articles

Science.gov (United States)

Kniajanski, Sergei; Soloveichik, Grigorii Lev

2018-02-20

An aqueous electrolyte composition is described, including a zinc salt based on zinc acetate or zinc glocolate. The saturation concentration of zinc in the electrolyte composition is in the range of about 2.5M to about 3.5M. The composition also contains at least one salt of a monovalent cation. The molar ratio of zinc to the monovalent cation is about 1:2. An aqueous zinc electroplating bath, containing the aqueous electrolyte composition, is also disclosed, along with a method for the electrochemical deposition of zinc onto a substrate surface, using the electroplating bath. Related flow batteries are also described, including a catholyte, as well as an anolyte based on the aqueous electrolyte composition, with a membrane between the catholyte and the anolyte.

Correlation and prediction of ion exchange equilibria on weak-acid resins by means of the surface complex formation model

International Nuclear Information System (INIS)

Horst, J.

1988-11-01

The present work summarizes investigations of the equilibrium of the exchange of protons, copper, zinc, calcium, magnesium and sodium ions on two weak-acid exchange resins in hydrochloric and carbonic acid bearing solutions at 25 0 C. The description of the state of equilibrium between resin and solution is based on the individual chemical equilibria which have to be adjusted simultaneously. The equilibrium in the liquid phase is described by the mass action law and the condition of electroneutrality using activity coefficients calculated according to the theory of Debye and Hueckel. The exchange equilibria are described by means of a surface complex formation model, which was developed by Davis, James and Leckie for activated aluminia and which has been applied to weak-acid resins. The model concept assumes the resin as a plane surface in which the functional groups are distributed uniformly. (orig./RB) [de

Proton microprobe analysis of zinc in skeletal tissues

Science.gov (United States)

Doty, S. B.; Jones, K. W.; Kraner, H. W.; Shroy, R. E.; Hanson, A. L.

1981-03-01

A proton microprobe with windowless exit port has been used to study zinc distributions in various types of skeletal tissues. The use of an external beam facilitated positioning of the targets for examination of particular points of interest. The proton microprobe is uniquely suited to this work since it combines high sensitivity for zinc determination in thick samples with good spatial resolution. Our measurements on rat and rabbit Achilles tendon showed a significant increase in zinc concentrations as the beam moved from the unmineralized collagen into the mineralized attachment site. Cartilage gave a similar result, with calcified cartilage having a greater zinc level than the articular surface on unmineralized epiphyseal cartilage.

Proton microprobe analysis of zinc in skeletal tissues

International Nuclear Information System (INIS)

Doty, S.B.; Jones, K.W.; Kraner, H.W.; Shroy, R.E.; Hanson, A.L.

1980-06-01

A proton microprobe with windowless exit port was used to study zinc distributions in various types of skeletal tissues. The use of an external beam facilitated positioning of the targets for examination of particular points of interest. The proton microprobe is uniquely suited to this work since it combines high sensitivity for zinc determinations in thick samples with good spatial resolution. Measurements on rat and rabbit Achilles tendon showed a significant increase in zinc concentrations as the beam moved from the unmineralized collagen into the mineralized attachment site. Cartilage gave a similar result, with calcified cartilage having a greater zinc level than the articular surface on unmineralized epiphyseal cartilage

Multisample conversion of water to hydrogen by zinc for stable isotope determination

Science.gov (United States)

Kendall, C.; Coplen, T.B.

1985-01-01

Two techniques for the conversion of water to hydrogen for stable isotope ratio determination have been developed that are especially suited for automated multisample analysis. Both procedures involve reaction of zinc shot with a water sample at 450 ??C. in one method designed for water samples in bottles, the water is put in capillaries and is reduced by zinc in reaction vessels; overall savings in sample preparation labor of 75% have been realized over the standard uranium reduction technique. The second technique is for waters evolved under vacuum and is a sealed-tube method employing 9 mm o.d. quartz tubing. Problems inherent with zinc reduction include surface inhomogeneity of the zinc and exchange of hydrogen both with the zinc and with the glass walls of the vessels. For best results, water/zinc and water/glass surface area ratios of vessels should be kept as large as possible.

First stages of zinc runoff in humid tropical climate

International Nuclear Information System (INIS)

Meraz, E.; Veleva, L.; Acosta, M.

2007-01-01

Frequently used metals in building application are Zinc and hot dip galvanized steel. The zinc has a relatively good atmospheric resistance, due to its oxidation in air and formation of protective layer. However, some of the zinc corrosion products can be dissolved by pluvial precipitations and water condensed on the metal surface. This process is called metal runoff. In order to estimate el zinc runoff in humid tropical climate, since its firs stages, samples of pure zinc and hot dip galvanized steel have been exposed during 2 years in outdoor atmosphere (rural and urban). The data reveal high annual values of zinc runoff (8,20-12,40±0.30 g/m''2 ano), being this process 80% of total mass loss of corroded zinc. The runoff and corrosion processes are more accelerated for zinc, than that of galvanized steel. The principal factors that control the runoff process are discussed. (Author) 48 refs

Protection against ionising radiation and synergism with thiols by zinc aspartate

International Nuclear Information System (INIS)

Floersheim, G.L.; Floersheim, P.

1986-01-01

Pre-treatment with zinc aspartate protected mice against the lethal effects of radiation and raised the LD 50 from 8 gy to 12.2 Gy. Zinc chloride and zinc sulphate were clearly less active. The radioprotective effect of zinc aspartate was equivalent to cysteamine and slightly inferior to S,2-aminoethylisothiourea (AET). Zinc aspartate displayed a similar therapeutic index to the thiols but could be applied at an earlier time before irradiation. Synergistic effects occurred with the combined administration of zinc aspartate and thiols. By giving zinc aspartate with cysteamine, the LD 50 was increased to 13.25 Gy and, by combining it in the optimal protocol with AET, to 17.3 Gy. The radioprotection by zinc and its synergism with thiols is explained by the stabilisation of thiols through the formation of zinc complexes. (author)

Diagnostic study of the roughness surface effect of zirconium on the third-order nonlinear-optical properties of thin films based on zinc oxide nanomaterials

Energy Technology Data Exchange (ETDEWEB)

Bahedi, K., E-mail: bahedikhadija@yahoo.com [Laboratoire Optoelectronique et Physico-chimie des Materiaux Universite Ibn Tofail, Faculte des Sciences BP 133 Kenitra 14000, Maroc (Morocco); Addou, M.; El Jouad, M.; Sofiani, Z.; Alaoui Lamrani, M.; El Habbani, T.; Fellahi, N.; Bayoud, S.; Dghoughi, L. [Laboratoire Optoelectronique et Physico-chimie des Materiaux Universite Ibn Tofail, Faculte des Sciences BP 133 Kenitra 14000, Maroc (Morocco); Sahraoui, B.; Essaidi, Z. [Laboratoire POMA, UMR CNRS 6136, Universite d' Angers 2, Bd Lavoisier, 49045 France (France)

2009-02-01

Zinc oxide (ZnO) and zirconium doped zinc oxide (ZnO:Zr) thin films were deposited by reactive chemical pulverization spray pyrolysis technique on heated glass substrates at 500 deg. C using zinc and zirconium chlorides as precursors. Effects of zirconium doping agent and surface roughness on the nonlinear optical properties were investigated in detail using atomic force microscopy (AFM) and third harmonic generation (THG) technique. The best value of nonlinear optical susceptibility {chi}{sup (3)} was obtained from the doped films with less roughness. A strong third order nonlinear optical susceptibility {chi}{sup (3)} = 20.12 x 10{sup -12} (esu) of the studied films was found for the 3% doped sample.

Electroplated zinc-cobalt alloy

International Nuclear Information System (INIS)

Carpenter, D.E.O.S.; Farr, J.P.G.

2005-01-01

Recent work on the deposition and use of ectrodeposited zinc-cobalt alloys is surveyed. Alloys containing lower of Nuclear quantities of cobalt are potentially more useful. The structures of the deposits is related to their chemical and mechanical properties. The inclusion of oxide and its role in the deposition mechanism may be significant. Chemical and engineering properties relate to the metallurgical structure of the alloys, which derives from the mechanism of deposition. The inclusion of oxides and hydroxides in the electroplate may provide evidence for this mechanism. Electrochemical impedance measurements have been made at significant deposition potentials, in alkaline electrolytes. These reveal a complex electrode behaviour which depends not only on the electrode potential but on the Co content of the electrolyte. For the relevant range of cathodic potential zinc-cobalt alloy electrodeposition occurs through a stratified interface. The formation of an absorbed layer ZnOH/sup +/ is the initial step, this inhibits the deposition of cobalt at low cathodic potentials, so explaining its 'anomalous deposition'. A porous layer of zinc forms on the adsorbed ZnOH/sup +/ at underpotential. As the potential becomes more cathodic, cobalt co- deposits from its electrolytic complex forming a metallic solid solution of Co in Zn. In electrolytes containing a high concentration of cobalt a mixed entity (ZnCo)/sub +/ is assumed to adsorb at the cathode from which a CoZn intermetallic deposits. (author)

Results of zinc injection test for Hamaoka Unit-1

International Nuclear Information System (INIS)

Kani, K.; Masuda, H.; Hayashi, Y.; Sudo, S.; Yamazaki, K.

1998-01-01

A zinc injection test was preformed at Hamaoka Nuclear Power Station Unit-1 for suppressing radiation dose rate on primary coolant recirculation piping after the replacement of piping. Zinc ion was injected by using injection system where Depleted Zinc Oxide was dissolved in carbonated water. Controllability of the system was sufficient to maintain concentration of zinc in primary water. The concentration of zinc in the primary coolant was controlled from 1 ppb to 5 ppb gradually. The increasing trend of concentration of Co-60 in the coolant was suppressed at zinc concentration of 3 ppb. It is evaluated that the deposition coefficient of Co-60 onto the surface of primary coolant recirculation piping was suppressed to one-third of previous cycle in average, and one-fourth of that just before injection start at zinc concentration of 5 ppb. We concluded that zinc injection is effective for suppressing dose rate on the primary coolant piping and no adverse effect occurs by zinc injection up to 5 ppb in the primary coolant. (J.P.N.)

LiZIP3 is a cellular zinc transporter that mediates the tightly regulated import of zinc in Leishmania infantum parasites

Science.gov (United States)

Carvalho, Sandra; da Silva, Rosa Barreira; Shawki, Ali; Castro, Helena; Lamy, Márcia; Eide, David; Costa, Vítor; Mackenzie, Bryan; Tomás, Ana M.

2016-01-01

Summary Cellular zinc homeostasis ensures that the intracellular concentration of this element is kept within limits that enable its participation in critical physiological processes without exerting toxic effects. We report here the identification and characterization of the first mediator of zinc homeostasis in Leishmania infantum, LiZIP3, a member of the ZIP family of divalent metal-ion transporters. The zinc transporter activity of LiZIP3 was first disclosed by its capacity to rescue the growth of Saccharomyces cerevisiae strains deficient in zinc acquisition. Subsequent expression of LiZIP3 in Xenopus laevis oocytes was shown to stimulate the uptake of a broad range of metal ions, among which Zn2+ was the preferred LiZIP3 substrate (K0.5 ≈ 0.1 μM). Evidence that LiZIP3 functions as a zinc importer in L. infantum came from the observations that the protein locates to the cell membrane and that its overexpression leads to augmented zinc internalization. Importantly, expression and cell-surface location of LiZIP3 are lost when parasites face high zinc bioavailability. LiZIP3 decline in response to zinc is regulated at the mRNA level in a process involving (a) short-lived protein(s). Collectively, our data reveal that LiZIP3 enables L. infantum to acquire zinc in a highly regulated manner, hence contributing to zinc homeostasis. PMID:25644708

Controlled Growth of ZnSe Nanocrystals by Tuning Reactivity and Amount of Zinc Precursor

Directory of Open Access Journals (Sweden)

Lai-Jun Zhang

2013-01-01

Full Text Available Zinc selenide (ZnSe nanocrystals were synthesized via a phosphine-free route using the highly reactive alkylamine-H2Se complex as selenium precursor and zinc precursors with different reactivity. The reactivity of zinc precursor was tuned by using three kinds of zinc carboxylates with different alkyl chain lengths, including zinc acetate, zinc nonanoate, and zinc stearate. The effect of the reactivity and the amount of zinc precursor on nucleation and growth of ZnSe nanocrystals were investigated by ultraviolet-visible absorption and photoluminescence spectra. Result indicates that the growth and optical property of the resulting ZnSe nanocrystals are strongly dependent on the alkyl chain length and the amount of the zinc carboxylates and both shorter alkyl chain length, and more amount of zinc carboxylate will lead to faster growth of ZnSe nanocrystals. This allows that the controlled growth and excellent optical property of high-quality ZnSe nanocrystals can be achieved by combining the different reactivity and the used amount of zinc precursor, such as by using stoichiometric and reactive Zn precursor and Se precursor or by using larger amount of more unreactive Zn precursor relative to the highly reactive alkylamine-H2Se complex precursor.

Electro-chemical deposition of nano hydroxyapatite-zinc coating on titanium metal substrate.

Science.gov (United States)

El-Wassefy, N A; Reicha, F M; Aref, N S

2017-08-13

Titanium is an inert metal that does not induce osteogenesis and has no antibacterial properties; it is proposed that hydroxyapatite coating can enhance its bioactivity, while zinc can contribute to antibacterial properties and improve osseointegration. A nano-sized hydroxyapatite-zinc coating was deposited on commercially pure titanium using an electro-chemical process, in order to increase its surface roughness and enhance adhesion properties. The hydroxyapatite-zinc coating was attained using an electro-chemical deposition in a solution composed of a naturally derived calcium carbonate, di-ammonium hydrogen phosphate, with a pure zinc metal as the anode and titanium as the cathode. The applied voltage was -2.5 for 2 h at a temperature of 85 °C. The resultant coating was characterized for its surface morphology and chemical composition using a scanning electron microscope (SEM), energy dispersive x-ray spectroscope (EDS), and Fourier transform infrared (FT-IR) spectrometer. The coated specimens were also evaluated for their surface roughness and adhesion quality. Hydroxyapatite-zinc coating had shown rosette-shaped, homogenous structure with nano-size distribution, as confirmed by SEM analysis. FT-IR and EDS proved that coatings are composed of hydroxyapatite (HA) and zinc. The surface roughness assessment revealed that the coating procedure had significantly increased average roughness (Ra) than the control, while the adhesive tape test demonstrated a high-quality adhesive coat with no laceration on tape removal. The developed in vitro electro-chemical method can be employed for the deposition of an even thickness of nano HA-Zn adhered coatings on titanium substrate and increases its surface roughness significantly.

Proton microprobe analysis of zinc in skeletal tissues

International Nuclear Information System (INIS)

Doty, S.B.; Jones, K.W.; Kraner, H.W.; Shroy, R.E.; Hanson, A.L.

1981-01-01

A proton microprobe with windowless exit port has been used to study zinc distributions in various types of skeletal tissues. The use of an external beam facilitated positioning of the targets for examination of particular points of interest. The proton micorprobe is uniquely suited to this work since it combines high sensitivity for zinc determinations in thick samples with good spatial resolution. Our measurements on rat and rabbit Achilles tendon showed a significant increase in zinc concentrations as the beam moved from the unmineralized collagen into the mineralized attachment site. Cartilage gave a similar result, with calcified cartilage having a greater zinc level than the articular surface on unmineralized epiphyseal cartilage. (orig.)

Dietary phytate, zinc and hidden zinc deficiency.

Science.gov (United States)

Sandstead, Harold H; Freeland-Graves, Jeanne H

2014-10-01

Epidemiological data suggest at least one in five humans are at risk of zinc deficiency. This is in large part because the phytate in cereals and legumes has not been removed during food preparation. Phytate, a potent indigestible ligand for zinc prevents it's absorption. Without knowledge of the frequency of consumption of foods rich in phytate, and foods rich in bioavailable zinc, the recognition of zinc deficiency early in the illness may be difficult. Plasma zinc is insensitive to early zinc deficiency. Serum ferritin concentration≤20μg/L is a potential indirect biomarker. Early effects of zinc deficiency are chemical, functional and may be "hidden". The clinical problem is illustrated by 2 studies that involved US Mexican-American children, and US premenopausal women. The children were consuming home diets that included traditional foods high in phytate. The premenopausal women were not eating red meat on a regular basis, and their consumption of phytate was mainly from bran breakfast cereals. In both studies the presence of zinc deficiency was proven by functional responses to controlled zinc treatment. In the children lean-mass, reasoning, and immunity were significantly affected. In the women memory, reasoning, and eye-hand coordination were significantly affected. A screening self-administered food frequency questionnaire for office might help caregiver's identify patients at risk of zinc deficiency. Copyright © 2014 Elsevier GmbH. All rights reserved.

An overview of zinc addition for BWR dose rate control

Energy Technology Data Exchange (ETDEWEB)

Marble, W.J. [GE Nuclear Energy, San Jose, CA (United States)

1995-03-01

This paper presents an overview of the BWRs employing feedwater zinc addition to reduce primary system dose rates. It identifies which BWRs are using zinc addition and reviews the mechanical injection and passive addition hardware currently being employed. The impact that zinc has on plant chemistry, including the factor of two to four reduction in reactor water Co-60 concentrations, is discussed. Dose rate results, showing the benefits of implementing zinc on either fresh piping surfaces or on pipes with existing films are reviewed. The advantages of using zinc that is isotopically enhanced by the depletion of the Zn-64 precursor to Zn-65 are identified.

Phenoxo bridged dinuclear Zn(II) Schiff base complex as new precursor for preparation zinc oxide nanoparticles: Synthesis, characterization, crystal structures and photoluminescence studies

Energy Technology Data Exchange (ETDEWEB)

Saeednia, S., E-mail: sami_saeednia@yahoo.com [Department of Chemistry, Faculty of Science, Vali-e-Asr University of Rafsanjan, Rafsanjan 77188-97111 (Iran, Islamic Republic of); Iranmanesh, P. [Department of physics, Faculty of Science, Vali-e-Asr University of Rafsanjan, Rafsanjan 77188-97111 (Iran, Islamic Republic of); Ardakani, M. Hatefi; Mohammadi, M.; Norouzi, Gh. [Department of Chemistry, Faculty of Science, Vali-e-Asr University of Rafsanjan, Rafsanjan 77188-97111 (Iran, Islamic Republic of)

2016-06-15

Highlights: • A novel nano-scale Zn(II) complex was synthesized by solvothermal method. • Chemical structure of the nanostructures was characterized as well as bulk complex. • The photoluminescence property of the complex was investigated at room temperature. • The thermogravimetry and differential thermal analysis were carried out. • Thermal decomposition of the nanostructures was prepared zinc oxide nanoparticles. - Abstract: Nanoparticles of a novel Zn(II) Schiff base complex, [Zn(HL)NO{sub 3}]{sub 2} (1), (H{sub 2}L = 2-[(2-hydroxy-propylimino) methyl] phenol), was synthesized by using solvothermal method. Shape, morphology and chemical structure of the synthesized nanoparticles were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Fourier Transform Infrared Spectoscopy (FT-IR) and UV–vis spectroscopy. Structural determination of compound 1 was determined by single-crystal X-ray diffraction. The results were revealed that the zinc complex is a centrosymmetric dimer in which deprotonated phenolates bridge the two five-coordinate metal atoms and link the two halves of the dimer. The thermal stability of compound 1 was analyzed by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The effect of the initial substrates concentration and reaction time on size and morphology of compound 1 nanostructure was investigated as well. Furthermore, the luminescent properties of the complex 1 were examined. ZnO nanoparticles with diameter between 15 and 20 nm were simply synthesized by solid-state transformation of compound 1 at 700 °C.

Zinc acetylacetonate hydrate adducted with nitrogen donor ligands: Synthesis, spectroscopic characterization, and thermal analysis

Science.gov (United States)

Brahma, Sanjaya; Shivashankar, S. A.

2015-12-01

We report synthesis, spectroscopic characterization, and thermal analysis of zinc acetylacetonate complex adducted by nitrogen donor ligands, such as pyridine, bipyridine, and phenanthroline. The pyridine adducted complex crystallizes to monoclinic crystal structure, whereas other two adducted complexes have orthorhombic structure. Addition of nitrogen donor ligands enhances the thermal property of these complexes as that with parent metal-organic complex. Zinc acetylacetonate adducted with pyridine shows much higher volatility (106 °C), decomposition temperature (202 °C) as that with zinc acetylacetonate (136 °C, 220 °C), and other adducted complexes. All the adducted complexes are thermally stable, highly volatile and are considered to be suitable precursors for metal organic chemical vapor deposition. The formation of these complexes is confirmed by powder X-ray diffraction, Fourier transform infrared spectroscopy, mass spectroscopy, and elemental analysis. The complexes are widely used as starting precursor materials for the synthesis of ZnO nanostructures by microwave irradiation assisted coating process.

Preparation, infrared, raman and nmr spectra of N,N'-diethylthiourea complexes with zinc(II), cadmium(II) and mercury(II) halides

Energy Technology Data Exchange (ETDEWEB)

Marcotrigiano, G [Bari Univ. (Italy). Cattedra di Chimica, Facolta di Medicina-Veterinaria

1976-05-01

Several complexes of N,N'-diethylthiourea (Dietu) with zinc(II), cadmium(II) and mercury(II) halides were prepared and characterized by i.r. (4000-60 cm/sup -1/), raman (400-60 cm/sup -1/), in the solid state and n.m.r. and conductometric methods in solution. The complexes Zn(Dietu)/sub 2/X/sub 2/, Cd(Dietu)/sub 2/X/sub 2/ (X=Cl, Br, I) and Hg(Dietu)/sub 2/X/sub 2/ (X=Br, I) are tetrahedral species in which intramolecular -NH...X interactions have been observed. The 1:1 mercury(II) complexes, Hg(Dietu)X/sub 2/ (X=Cl, Br), appear to have a dimeric tetrahedral halide-bridged structure in the solid state. In all these complexes N,N'-diethylthiourea is sulphur-bonded to the metal.

Fluorescent zinc–terpyridine complex containing coordinated ...

Indian Academy of Sciences (India)

Unknown

Keywords. Zinc peroxo complex; terpyridine complexes; fluorescence ... structure determination 3. Zinc is an essential element for normal function of most .... 63 179; (d) De Silva A P, Gunaratna H Q N, Gunnlaugsson T, Huxley A J M, Mcloy C.

Potential ecological risk assessment and predicting zinc accumulation in soils.

Science.gov (United States)

Baran, Agnieszka; Wieczorek, Jerzy; Mazurek, Ryszard; Urbański, Krzysztof; Klimkowicz-Pawlas, Agnieszka

2018-02-01

The aims of this study were to investigate zinc content in the studied soils; evaluate the efficiency of geostatistics in presenting spatial variability of zinc in the soils; assess bioavailable forms of zinc in the soils and to assess soil-zinc binding ability; and to estimate the potential ecological risk of zinc in soils. The study was conducted in southern Poland, in the Malopolska Province. This area is characterized by a great diversity of geological structures and types of land use and intensity of industrial development. The zinc content was affected by soil factors, and the type of land use (arable lands, grasslands, forests, wastelands). A total of 320 soil samples were characterized in terms of physicochemical properties (texture, pH, organic C content, total and available Zn content). Based on the obtained data, assessment of the ecological risk of zinc was conducted using two methods: potential ecological risk index and hazard quotient. Total Zn content in the soils ranged from 8.27 to 7221 mg kg -1 d.m. Based on the surface semivariograms, the highest variability of zinc in the soils was observed from northwest to southeast. The point sources of Zn contamination were located in the northwestern part of the area, near the mining-metallurgical activity involving processing of zinc and lead ores. These findings were confirmed by the arrangement of semivariogram surfaces and bivariate Moran's correlation coefficients. The content of bioavailable forms of zinc was between 0.05 and 46.19 mg kg -1 d.m. (0.01 mol dm -3 CaCl 2 ), and between 0.03 and 71.54 mg kg -1 d.m. (1 mol dm -3 NH 4 NO 3 ). Forest soils had the highest zinc solubility, followed by arable land, grassland and wasteland. PCA showed that organic C was the key factor to control bioavailability of zinc in the soils. The extreme, very high and medium zinc accumulation was found in 69% of studied soils. There is no ecological risk of zinc to living organisms in the study area, and in 90

Deposition and surface characterization of nanoparticles of zinc oxide using dense plasma focus device in nitrogen atmosphere

International Nuclear Information System (INIS)

Malhotra, Yashi; Srivastava, M P; Roy, Savita

2010-01-01

Nanoparticles of zinc oxide from zinc oxide pellets in the nitrogen plasma atmosphere are deposited on n and p type silicon substrates using Dense Plasma Focus device. The hot and dense nitrogen plasma formed during the focus phase ionizes the ZnO pellet, which then move upward in a fountain like shape and gets deposited on substrates which are placed above the top of the anode. Structural and surface properties of the deposited ZnO are investigated using X-ray diffraction and Atomic force microscope (AFM). X-ray spectra shows the diffraction plane (002) of ZnO nanoparticles deposited on Si with few shots in nitrogen atmosphere. AFM investigations revealed that there are nanoparticles of size between 15-80 nm on n-Si and p-Si substrates. The deposition on n-type Si is better than the p-type Si can be seen from AFM images, this may be due to different orientation of silicon.

Alkali-crown ether complexes at metal surfaces

Energy Technology Data Exchange (ETDEWEB)

Thontasen, Nicha; Deng, Zhitao; Rauschenbach, Stephan [Max Planck Institute for Solid State Research, Stuttgart (Germany); Levita, Giacomo [University of Trieste, Trieste (Italy); Malinowski, Nikola [Max Planck Institute for Solid State Research, Stuttgart (Germany); Bulgarian Academy of Sciences, Sofia (Bulgaria); Kern, Klaus [Max Planck Institute for Solid State Research, Stuttgart (Germany); EPFL, Lausanne (Switzerland)

2010-07-01

Crown ethers are polycyclic ethers which, in solution, selectively bind cations depending on the size of the ring cavity. The study of a single host-guest complex is highly desirable in order to reveal the characteristics of these specific interactions at the atomic scale. Such detailed investigation is possible at the surface where high resolution imaging tools like scanning tunneling microscopy (STM) can be applied. Here, electrospray ion beam deposition (ES-IBD) is employed for the deposition of Dibenzo-24-crown-8 (DB24C8)-H{sup +}, -Na{sup +} and -Cs{sup +} complexes on a solid surface in ultrahigh vacuum (UHV). Where other deposition techniques have not been successful, this deposition technique combines the advantages of solution based preparation of the complex ions with a highly clean and controlled deposition in UHV. Single molecular structures and the cation-binding of DB24C8 at the surface are studied in situ by STM and MALDI-MS (matrix assisted laser desorption ionization mass spectrometry). The internal structure of the complex, i.e. ring and cavity, is observable only when alkali cations are incorporated. The BD24C8-H{sup +} complex in contrast appears as a compact feature. This result is in good agreement with theoretical models based on density functional theory calculations.

Shaping optimal zinc coating on the surface of high-quality ductile iron casting. Part II – Technological formula and value of diffusion coefficient

Directory of Open Access Journals (Sweden)

Kopyciński D.

2017-03-01

Full Text Available The completed research presented in the first part of the article has allowed linking the manufacturing technology of ductile iron castings with the process of hot dip galvanizing. On the basis of these data simulations were carried out to examine the behaviour of zinc diffusion coefficient D in the galvanized coating. The adopted model of zinc coating growth helped to explain the cases of excessive growth of the intermetallic phases in this type of coating. The paper analyzes covered the relationship between the roughness and phase composition of the top layer of product and the thickness and kinetics of zinc coating growth referred to individual sub-layers of the intermetallic phases.Roughness and phase composition in the surface layer of product were next related to the diffusion coefficient D examined in respective sublayers of the intermetallic phases.

Path coefficient analysis of zinc dynamics in varying soil environment

International Nuclear Information System (INIS)

Rattan, R.K.; Phung, C.V.; Singhal, S.K.; Deb, D.L.; Singh, A.K.

1994-01-01

Influence of soil properties on labile zinc, as measured by diethylene-triamine pentaacetic acid (DTPA) and zinc-65, and self-diffusion coefficients of zinc was assessed on 22 surface soil samples varying widely in their characteristics following linear regression and path coefficient analysis techniques. DTPA extractable zinc could be predicted from organic carbon status and pH of the soil with a highly significant coefficient of determination (R 2 =0.84 ** ). Ninety seven per cent variation in isotopically exchangeable zinc was explained by pH, clay content and cation exchange capacity (CEC) of soil. The self-diffusion coefficients (DaZn and DpZn) and buffer power of zinc exhibited exponential relationship with soil properties, pH being the most dominant one. Soil properties like organic matter, clay content etc. exhibited indirect effects on zinc diffusion rates via pH only. (author). 13 refs., 6 tabs

Zinc-induced Self-association of Complement C3b and Factor H

Science.gov (United States)

Nan, Ruodan; Tetchner, Stuart; Rodriguez, Elizabeth; Pao, Po-Jung; Gor, Jayesh; Lengyel, Imre; Perkins, Stephen J.

2013-01-01

The sub-retinal pigment epithelial deposits that are a hallmark of age-related macular degeneration contain both C3b and millimolar levels of zinc. C3 is the central protein of complement, whereas C3u is formed by the spontaneous hydrolysis of the thioester bridge in C3. During activation, C3 is cleaved to form active C3b, then C3b is inactivated by Factor I and Factor H to form the C3c and C3d fragments. The interaction of zinc with C3 was quantified using analytical ultracentrifugation and x-ray scattering. C3, C3u, and C3b associated strongly in >100 μm zinc, whereas C3c and C3d showed weak association. With zinc, C3 forms soluble oligomers, whereas C3u and C3b precipitate. We conclude that the C3, C3u, and C3b association with zinc depended on the relative positions of C3d and C3c in each protein. Computational predictions showed that putative weak zinc binding sites with different capacities exist in all five proteins, in agreement with experiments. Factor H forms large oligomers in >10 μm zinc. In contrast to C3b or Factor H alone, the solubility of the central C3b-Factor H complex was much reduced at 60 μm zinc and even more so at >100 μm zinc. The removal of the C3b-Factor H complex by zinc explains the reduced C3u/C3b inactivation rates by zinc. Zinc-induced precipitation may contribute to the initial development of sub-retinal pigment epithelial deposits in the retina as well as reducing the progression to advanced age-related macular degeneration in higher risk patients. PMID:23661701

Influence of Zinc on the Surface Tension, Density and Molar Volume of (Ag-Sneut +Zn Liquid Alloys

Directory of Open Access Journals (Sweden)

Gąsior W.

2016-03-01

Full Text Available The dilatometric and maximum bubble pressure methods were applied for the measurements of the density and surface tension of liquid (Ag-Sneut +Zn lead-free solders. The experiments were carried out in the temperature range from 515 to 1223 K for the alloys of the zinc concentration equaling 0.01, 0.02, 0.04, 0.05, 0.1 and 0.2 of the mole fraction. It was found that the temperature dependence of both the density and the surface tension could be thought as linear, so they were interpreted by straight line equations. The experimental data of the molar volume of the investigated alloys were described by the polynomial dependent on the composition and temperature.

Accelerated bone ingrowth by local delivery of Zinc from bioactive ...

African Journals Online (AJOL)

2015-10-19

Oct 19, 2015 ... Aims: This study aims to evaluate in vivo the performance therapy of zinc-doped bioactive glass (BG-Zn) and ... Keywords: zinc metallic ion; bioactive glass; osteoporosis; trabecular bone architecture; mechanical property; oxidative stress ..... Ducheyne P, Qiu Q. Bioactive ceramics: the effect of surface.

Compartmentation of metals in foliage of Populus tremula grown on soils with mixed contamination. II. Zinc binding inside leaf cell organelles

Energy Technology Data Exchange (ETDEWEB)

Vollenweider, Pierre, E-mail: pierre.vollenweider@wsl.c [Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zuercherstrasse 111, 8903 Birmensdorf (Switzerland); Bernasconi, Petra [Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zuercherstrasse 111, 8903 Birmensdorf (Switzerland); Environmental Protection Office (AfU), Aabachstrasse 5, 6300 Zug (Switzerland); Gautschi, Hans-Peter [Centre for Microscopy and Image Analysis (CMI), University of Zurich, Gloriastrasse 30, 8006 Zuerich (Switzerland); Menard, Terry; Frey, Beat; Guenthardt-Goerg, Madeleine S. [Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zuercherstrasse 111, 8903 Birmensdorf (Switzerland)

2011-01-15

The phytoextraction potential of plants for removing heavy metals from polluted soils is determined by their capacity to store contaminants in aboveground organs and complex them safely. In this study, the metal compartmentation, elemental composition of zinc deposits and zinc complexation within leaves from poplars grown on soil with mixed metal contamination was analysed combining several histochemical and microanalytical approaches. Zinc was the only heavy metal detected and was stored in several organelles in the form of globoid deposits showing {beta}-metachromasy. It was associated to oxygen anions and different cations, noteworthy phosphorous. The deposit structure, elemental composition and element ratios indicated that zinc was chelated by phytic acid ligands. Maturation processes in vacuolar vs. cytoplasmic deposits were suggested by differences in size and amounts of complexed zinc. Hence, zinc complexation by phytate contributed to metal detoxification and accumulation in foliage but could not prevent toxicity reactions therein. - Zinc contaminants translocated to symplast of aged leaves were detoxified by phytic acid ligands.

Compartmentation of metals in foliage of Populus tremula grown on soils with mixed contamination. II. Zinc binding inside leaf cell organelles

International Nuclear Information System (INIS)

Vollenweider, Pierre; Bernasconi, Petra; Gautschi, Hans-Peter; Menard, Terry; Frey, Beat; Guenthardt-Goerg, Madeleine S.

2011-01-01

The phytoextraction potential of plants for removing heavy metals from polluted soils is determined by their capacity to store contaminants in aboveground organs and complex them safely. In this study, the metal compartmentation, elemental composition of zinc deposits and zinc complexation within leaves from poplars grown on soil with mixed metal contamination was analysed combining several histochemical and microanalytical approaches. Zinc was the only heavy metal detected and was stored in several organelles in the form of globoid deposits showing β-metachromasy. It was associated to oxygen anions and different cations, noteworthy phosphorous. The deposit structure, elemental composition and element ratios indicated that zinc was chelated by phytic acid ligands. Maturation processes in vacuolar vs. cytoplasmic deposits were suggested by differences in size and amounts of complexed zinc. Hence, zinc complexation by phytate contributed to metal detoxification and accumulation in foliage but could not prevent toxicity reactions therein. - Zinc contaminants translocated to symplast of aged leaves were detoxified by phytic acid ligands.

NMR investigation of dynamic processes in complexes of nickel(II) and zinc(II) with iminodiacetate, n-methyliminodiacetate and n-ethyliminodiacetate

International Nuclear Information System (INIS)

Wagner, M.R.

1985-11-01

Analysis of oxygen-17 bulk water relaxation rates with an aqueous solution of 1:1 Ni(II):ida reveals that two rate-limiting processes are involved with solvent exchange. Analysis of carbon-13 longitudinal relaxation rates of the bis-ligand complexes with zinc(II) are used to determine molecular tumbling rates and methyl rotation rates. The carbon-13 transverse relaxation rates for the carbons in the bis-ligand complex with Ni(II) are adequately fitted to the Solomon-Bloembergen equation. Three carboxylate carbon peaks are seen with the 13 C spectrum of the 1:2 Ni(II):ida complex, which coalesce into a single peak above about 360 K. The mechanism and rate of ligand exchange are determined for the complexes Zn(II)L 2 -2 (L = mida, eida) in aqueous solution by total lineshape analysis of the proton spectrum at 500 MHz

[Improvement in zinc nutrition due to zinc transporter-targeting strategy].

Science.gov (United States)

Kambe, Taiho

2016-07-01

Adequate intake of zinc from the daily diet is indispensable to maintain health. However, the dietary zinc content often fails to fulfill the recommended daily intake, leading to zinc deficiency and also increases the risk of developing chronic diseases, particularly in elderly individuals. Therefore, increased attention is required to overcome zinc deficiency and it is important to improve zinc nutrition in daily life. In the small intestine, the zinc transporter, ZIP4, functions as a component that is essential for zinc absorption. In this manuscript, we present a brief overview regarding zinc deficiency. Moreover, we review a novel strategy, called "ZIP4-targeting", which has the potential to enable efficient zinc absorption from the diet. ZIP4-targeting strategy is possibly a major step in preventing zinc deficiency and improving human health.

Remediation of arsenic and lead with nanocrystalline zinc sulfide.

Science.gov (United States)

Piquette, Alan; Cannon, Cody; Apblett, Allen W

2012-07-27

Nanocrystalline (1.7 ± 0.3 nm) zinc sulfide with a specific surface area up to 360 m(2) g(-1) was prepared from the thermal decomposition of a single-source precursor, zinc ethylxanthate. Zinc ethylxanthate decomposes to cubic zinc sulfide upon exposure to temperatures greater than or equal to 125 °C. The resulting zinc sulfide was tested as a water impurity extractant. The target impurities used in this study were As(5+), As(3+), and Pb(2+). The reaction of the nanocrystalline ZnS with Pb(2+) proceeds as a replacement reaction where solid PbS is formed and Zn(2+) is released into the aqueous system. Removal of lead to a level of less than two parts per billion is achievable. The results of a detailed kinetics experiment between the ZnS and Pb(2+) are included in this study. Unlike the instance of lead, both As(5+) and As(3+) adsorb on the surface of the ZnS extractant as opposed to an ion-exchange process. An uptake capacity of > 25 mg g(-1) for the removal of As(5+) is possible. The uptake of As(3+) appears to proceed by a slower process than that of the As(5+) with a capacity of nearly 20 mg g(-1). The nanocrystalline zinc sulfide was extremely successful for the removal of arsenic and lead from simulated oil sand tailing pond water.

Zinc content of selected tissues and taste perception in rats fed zinc deficient and zinc adequate rations

International Nuclear Information System (INIS)

Boeckner, L.S.; Kies, C.

1986-01-01

The objective of the study was to determine the effects of feeding zinc sufficient and zinc deficient rations on taste sensitivity and zinc contents of selected organs in rats. The 36 Sprague-Dawley male weanling rats were divided into 2 groups and fed zinc deficient or zinc adequate rations. The animals were subjected to 4 trial periods in which a choice of deionized distilled water or a solution of quinine sulfate at 1.28 x 10 -6 was given. A randomized schedule for rat sacrifice was used. No differences were found between zinc deficient and zinc adequate rats in taste preference aversion scores for quinine sulfate in the first three trial periods; however, in the last trial period rats in the zinc sufficient group drank somewhat less water containing quinine sulfate as a percentage of total water consumption than did rats fed the zinc deficient ration. Significantly higher zinc contents of kidney, brain and parotid salivary glands were seen in zinc adequate rats compared to zinc deficient rats at the end of the study. However, liver and tongue zinc levels were lower for both groups at the close of the study than were those of rats sacrificed at the beginning of the study

Pan-Domain Analysis of ZIP Zinc Transporters

Directory of Open Access Journals (Sweden)

Laura E. Lehtovirta-Morley

2017-12-01

Full Text Available The ZIP (Zrt/Irt-like protein family of zinc transporters is found in all three domains of life. However, little is known about the phylogenetic relationship amongst ZIP transporters, their distribution, or their origin. Here we employed phylogenetic analysis to explore the evolution of ZIP transporters, with a focus on the major human fungal pathogen, Candida albicans. Pan-domain analysis of bacterial, archaeal, fungal, and human proteins revealed a complex relationship amongst the ZIP family members. Here we report (i a eukaryote-wide group of cellular zinc importers, (ii a fungal-specific group of zinc importers having genetic association with the fungal zincophore, and, (iii a pan-kingdom supercluster made up of two distinct subgroups with orthologues in bacterial, archaeal, and eukaryotic phyla.

Development of surface plasmon resonance sensor for determining zinc ion using novel active nanolayers as probe.

Science.gov (United States)

Fen, Yap Wing; Yunus, W Mahmood Mat; Talib, Zainal Abidin; Yusof, Nor Azah

2015-01-05

In this study, novel active nanolayers in combination with surface plasmon resonance (SPR) system for zinc ion (Zn(2+)) detection has been developed. The gold surface used for the SPR system was modified with the novel developed active nanolayers, i.e. chitosan and chitosan-tetrabutyl thiuram disulfide (chitosan-TBTDS). Both chitosan and chitosan-TBTDS active layers were fabricated on the gold surface by spin coating technique. The system was used to monitor SPR signal for Zn(2+) in aqueous media with and without sensitivity enhancement by TBTDS. For both active nanolayers, the shift of resonance angle is directly proportional to the concentration of Zn(2+) in aqueous media. The higher shift of resonance angle was obtained for chitosan-TBTDS active nanolayer due to a specific binding of TBTDS with Zn(2+). The chitosan-TBTDS active nanolayer enhanced the sensitivity of detection down to 0.1 mg/l and also induced a selective detection towards Zn(2+). Copyright © 2014 Elsevier B.V. All rights reserved.

Zinc and lead transfer in a contaminated roadside soil: Experimental study and modeling

International Nuclear Information System (INIS)

Hanna, K.; Lassabatere, L.; Bechet, B.

2009-01-01

The application of a surface complexation model to simulate the sorption of metals on single sorbents is very well investigated, but very little is known regarding the use of surface complexation modeling to simulate the metal mobility in contaminated roadside soils. The overall objective of this study was to examine whether the use of the surface complexation model (SCM) could correctly describe the migration of zinc and lead in roadside soil under various physicochemical conditions. The release and transport of Zn and Pb was studied by means of batch reactors and saturated chromatography columns. Soil batch experiments were conducted to evaluate the effects of pH variation and ionic strength on the metal mobility from soil. Elution of Pb and Zn was examined in column experiments by using acetic acid at pH5 and EDTA at pH7. The modeling work has focused on the development of a SCM using MINTEQ2 database incorporated in PHREEQC-2 to describe the interactions between trace metals and the main mineral soil components (quartz, iron and aluminum oxides). In this study, it was found that the SCM was able to simulate the mobility of metals from soil by assuming one mononuclear surface reaction between one solution species (Me 2+ ) and one type of site on the surface of soil dominant sorbents

Surface-complexation models for sorption onto heterogeneous surfaces

International Nuclear Information System (INIS)

Harvey, K.B.

1997-10-01

This report provides a description of the discrete-logK spectrum model, together with a description of its derivation, and of its place in the larger context of surface-complexation modelling. The tools necessary to apply the discrete-logK spectrum model are discussed, and background information appropriate to this discussion is supplied as appendices. (author)

Nanocrystalline zinc oxide for the decontamination of sarin

Energy Technology Data Exchange (ETDEWEB)

Mahato, T.H. [Defense R and D Establishment, Jhansi Road, 474002, Gwalior, MP (India); Prasad, G.K., E-mail: gkprasad@lycos.com [Defense R and D Establishment, Jhansi Road, 474002, Gwalior, MP (India); Singh, Beer; Acharya, J.; Srivastava, A.R.; Vijayaraghavan, R. [Defense R and D Establishment, Jhansi Road, 474002, Gwalior, MP (India)

2009-06-15

Nanocrystalline zinc oxide materials were prepared by sol-gel method and were characterized by X-ray diffraction, scanning electron microscopy, thermogravimetry, nitrogen adsorption and infrared spectroscopy techniques. The data confirmed the formation of zinc oxide materials of zincite phase with an average crystallite size of {approx}55 nm. Obtained material was tested as destructive adsorbent for the decontamination of sarin and the reaction was followed by GC-NPD and GC-MS techniques. The reaction products were characterized by GC-MS and the data explored the role of hydrolysis reaction in the detoxification of sarin. Sarin was hydrolyzed to form surface bound non-toxic phosphonate on the surface of nano-zinc oxide. The data also revealed the values of rate constant and half-life to be 4.12 h{sup -1} and 0.16 h in the initial stages of the reaction and 0.361 h{sup -1} and 1.9 h at the final stages of the reaction for the decontamination reaction on nanocrystalline ZnO.

Nanocrystalline zinc oxide for the decontamination of sarin

International Nuclear Information System (INIS)

Mahato, T.H.; Prasad, G.K.; Singh, Beer; Acharya, J.; Srivastava, A.R.; Vijayaraghavan, R.

2009-01-01

Nanocrystalline zinc oxide materials were prepared by sol-gel method and were characterized by X-ray diffraction, scanning electron microscopy, thermogravimetry, nitrogen adsorption and infrared spectroscopy techniques. The data confirmed the formation of zinc oxide materials of zincite phase with an average crystallite size of ∼55 nm. Obtained material was tested as destructive adsorbent for the decontamination of sarin and the reaction was followed by GC-NPD and GC-MS techniques. The reaction products were characterized by GC-MS and the data explored the role of hydrolysis reaction in the detoxification of sarin. Sarin was hydrolyzed to form surface bound non-toxic phosphonate on the surface of nano-zinc oxide. The data also revealed the values of rate constant and half-life to be 4.12 h -1 and 0.16 h in the initial stages of the reaction and 0.361 h -1 and 1.9 h at the final stages of the reaction for the decontamination reaction on nanocrystalline ZnO.

Evaluation of sources, rates and methods of zinc fertilizer applications in flooded rice

International Nuclear Information System (INIS)

Sarkar, A.K.; Deb, D.L.

1981-01-01

A pot experiment was conducted using 65 Zn as tracer to evaluate the different sources, levels and methods of zinc fertilization in flooded rice. Results indicated that zinc sulphate was either at par or slightly superior to zincated urea from the point of view of yield and total zinc uptake by rice. The Zndff percent was found to be the highest with zincated urea and the lowest was observed with zinc oxide. 5 and 10 kg/ha levels of zinc were statistically at par in this regard. Among the different methods, surface application and thorough mixing with soil were comparable. Root dipping in 1 percent zinc oxide suspension and application of zinc in irrigation water also indicated high zinc absorption by the rice plant. (author)

Corrosion resistance of zinc-magnesium coated steel

International Nuclear Information System (INIS)

Hosking, N.C.; Stroem, M.A.; Shipway, P.H.; Rudd, C.D.

2007-01-01

A significant body of work exists in the literature concerning the corrosion behaviour of zinc-magnesium coated steel (ZMG), describing its enhanced corrosion resistance when compared to conventional zinc-coated steel. This paper begins with a review of the literature and identifies key themes in the reported mechanisms for the attractive properties of this material. This is followed by an experimental programme where ZMG was subjected to an automotive laboratory corrosion test using acidified NaCl solution. A 3-fold increase in time to red rust compared to conventional zinc coatings was measured. X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy were used to characterize the corrosion products formed. The corrosion products detected on ZMG included simonkolleite (Zn 5 Cl 2 (OH) 8 . H 2 O), possibly modified by magnesium uptake, magnesium hydroxide (Mg(OH) 2 ) and a hydroxy carbonate species. It is proposed that the oxygen reduction activity at the (zinc) cathodes is reduced by precipitation of alkali-resistant Mg(OH) 2 , which is gradually converted to more soluble hydroxy carbonates by uptake of atmospheric carbon dioxide. This lowers the surface pH sufficiently to allow thermodynamically for general precipitation of insoluble simonkolleite over the corroding surface thereby retarding the overall corrosion reactions, leaving only small traces of magnesium corrosion products behind. Such a mechanism is consistent with the experimental findings reported in the literature

Compact complex surfaces with geometric structures related to split quaternions

International Nuclear Information System (INIS)

Davidov, Johann; Grantcharov, Gueo; Mushkarov, Oleg; Yotov, Miroslav

2012-01-01

We study the problem of existence of geometric structures on compact complex surfaces that are related to split quaternions. These structures, called para-hypercomplex, para-hyperhermitian and para-hyperkähler, are analogs of the hypercomplex, hyperhermitian and hyperkähler structures in the definite case. We show that a compact 4-manifold carries a para-hyperkähler structure iff it has a metric of split signature together with two parallel, null, orthogonal, pointwise linearly independent vector fields. Every compact complex surface admitting a para-hyperhermitian structure has vanishing first Chern class and we show that, unlike the definite case, many of these surfaces carry infinite-dimensional families of such structures. We provide also compact examples of complex surfaces with para-hyperhermitian structures which are not locally conformally para-hyperkähler. Finally, we discuss the problem of non-existence of para-hyperhermitian structures on Inoue surfaces of type S 0 and provide a list of compact complex surfaces which could carry para-hypercomplex structures.

Natively textured surface hydrogenated gallium-doped zinc oxide transparent conductive thin films with buffer layers for solar cells

Energy Technology Data Exchange (ETDEWEB)

Chen, Xin-liang, E-mail: cxlruzhou@163.com; Wang, Fei; Geng, Xin-hua; Huang, Qian; Zhao, Ying; Zhang, Xiao-dan

2013-09-02

Natively textured surface hydrogenated gallium-doped zinc oxide (HGZO) thin films have been deposited via magnetron sputtering on glass substrates. These natively textured HGZO thin films exhibit rough pyramid-like textured surface, high optical transmittances in the visible and near infrared region and excellent electrical properties. The experiment results indicate that tungsten-doped indium oxide (In{sub 2}O{sub 3}:W, IWO) buffer layers can effectively improve the surface roughness and enhance the light scattering ability of HGZO thin films. The root-mean-square roughness of HGZO, IWO (10 nm)/HGZO and IWO (30 nm)/HGZO thin films are 28, 44 and 47 nm, respectively. The haze values at the wavelength of 550 nm increase from 7.0% of HGZO thin film without buffer layer to 18.37% of IWO (10 nm)/HGZO thin film. The optimized IWO (10 nm)/HGZO exhibits a high optical transmittance of 82.18% in the visible and near infrared region (λ ∼ 400–1100 nm) and excellent electrical properties with a relatively low sheet resistance of 3.6 Ω/□ and the resistivity of 6.21 × 10{sup −4} Ωcm. - Highlights: • Textured hydrogenated gallium-doped zinc oxide (HGZO) films were developed. • Tungsten-doped indium oxide (IWO) buffer layers were applied for the HGZO films. • Light-scattering ability of the HGZO films can be improved through buffer layers. • Low sheet resistance and high haze were obtained for the IWO(10 nm)/HGZO film. • The IWO/HGZO films are promising transparent conductive layers for solar cells.

Factors affecting the hot-dip zinc coatings structure

International Nuclear Information System (INIS)

Sere, P.R.; Cuclcasi, J.D.; Elsner, C.I.; Sarli, A.R.

1997-01-01

Coating solidification during hot-dip galvanizing is a very complex process due to Al-Fe, Al-Fe-Zn and Fe-Zn intermetallic compounds development . Fe-Zn intermetallics are brittle and detrimental for the coating ductility, while the diffusion towards the surface of a segregated insoluble alloying such as antimonium causes the sheet darkness. Steel of different roughness were hot-dip galvanized under different operation conditions using a laboratory scale simulator. The effect of steel roughness and process parameters upon coating characteristics were analysed. Experimental results showed that the steel roughness affects the coating thickness, zinc grain size and texture as well as the out-bursts development, while the process parameters affects the Fe 2 Al 5 morphology and antimonium segregation. (Author) 11 refs

Effect of soluble zinc additions on the SCC performance of nickel alloys in deaerated hydrogenated water

International Nuclear Information System (INIS)

Morton, D.S.; Thompson, C.D.; Gladding, D.; Schurman, M.K.

1997-08-01

Stress corrosion crack growth rates (SCCGR) of alloy 600, EN82H and X-750 were measured in deaerated hydrogenated water to determine if soluble zinc mitigates SCCGR. Constant load compact tension specimen tests were conducted. Two test strategies were used to discern a possible zinc effect. The first strategy employed separate SCCGR tests in zinc and non-zinc environments and compared the resulting crack growth rates. The second strategy varied zinc levels at the midterm of single specimen SCCGR tests and characterized the resulting crack growth rate effect through an electrical potential drop in-situ crack monitor. Results from the direct comparison and midterm changing chemistry tests did not discern a zinc influence; any apparent zinc influence is within test to test variability (∼1.5x change in crack growth rate). AEM, AUGER and ESCA crack tip fracture surface studies identified that zinc was not incorporated within crack tip oxides. These studies identified nickel rich crack tip oxides and spinel, with incorporated zinc, (∼5 atom percent) bulk surface oxides

Leaching of zinc from rubber infill on artificial turf (football pitches)

NARCIS (Netherlands)

Verschoor AJ; LER

2007-01-01

Many artificial football pitches are treated with a rubber infill made of recycled tyres. From this material zinc leaches to the soil, groundwater and surface water. [This can present significant environmental risks, particularly for aquatic life.] Human health risks posed by leaching of zinc are

Environmental significance of copper, lead, manganese, uranium and zinc speciation in the event of contaminated waters release from the Ranger Uranium Mining Complex

International Nuclear Information System (INIS)

Noller, B.N.; Currey, N.A.

1983-01-01

The likely impact of the accidental release of tailings dam water during the dry season at the Ranger Uranium Mining Complex was examined. A speciation scheme utilising sizing by filtration and ion-exchange with Chelex 100 has given an insight into the likely partitioning of zinc, copper, lead, manganese and uranium following the addition of tailings dam water to samples from waterbodies in the vicinity of the uranium mining/milling complex. The speciation findings are discussed in terms of likely toxic effects on fish

Zinc-Modified Nanotransporter of Doxorubicin for Targeted Prostate Cancer Delivery

Directory of Open Access Journals (Sweden)

Sylvie Skalickova

2017-12-01

Full Text Available This work investigated the preparation of chitosan nanoparticles used as carriers for doxorubicin for targeted cancer delivery. Prepared nanocarriers were stabilized and functionalized via zinc ions incorporated into the chitosan nanoparticle backbone. We took the advantage of high expression of sarcosine in the prostate cancer cells. The prostate cancer targeting was mediated by the AntiSar antibodies decorated surface of the nanocage. Formation of the chitosan nanoparticles was determined using a ninhydrin assay and differential pulse voltammetry. Obtained results showed the strong effect of tripolyphosphine on the nanoparticle formation. The zinc ions affected strong chitosan backbone coiling both in inner and outer chitosan nanoparticle structure. Zinc electrochemical signal depended on the level of the complex formation and the potential shift from −960 to −950 mV. Formed complex is suitable for doxorubicin delivery. It was observed the 20% entrapment efficiency of doxorubicin and strong dependence of drug release after 120 min in the blood environment. The functionality of the designed nanotransporter was proven. The purposed determination showed linear dependence in the concentration range of Anti-sarcosine IgG labeled gold nanoparticles from 0 to 1000 µg/mL and the regression equation was found to be y = 3.8x − 66.7 and R2 = 0.99. Performed ELISA confirmed the ability of Anti-sarcosine IgG labeled chitosan nanoparticles with loaded doxorubicin to bind to the sarcosine molecule. Observed hemolytic activity of the nanotransporter was 40%. Inhibition activity of our proposed nanotransporter was evaluated to be 0% on the experimental model of S. cerevisiae. Anti-sarcosine IgG labeled chitosan nanoparticles, with loaded doxorubicin stabilized by Zn ions, are a perspective type of nanocarrier for targeted drug therapy managed by specific interaction with sarcosine and metallothionein for prostate cancer.

Chemical-Biological Properties of Zinc Sensors TSQ and Zinquin: Formation of Sensor-Zn-Protein Adducts versus Zn(Sensor)2 Complexes.

Science.gov (United States)

Nowakowski, Andrew B; Meeusen, Jeffrey W; Menden, Heather; Tomasiewicz, Henry; Petering, David H

2015-12-21

Fluorescent zinc sensors are the most commonly used tool to study the intracellular mobile zinc status within cellular systems. Previously, we have shown that the quinoline-based sensors Zinquin and 6-methoxy-8-p-toluenesulfonamido-quinoline (TSQ) predominantly form ternary adducts with members of the Zn-proteome. Here, the chemistries of these sensors are further characterized, including how Zn(sensor)2 complexes may react in an intracellular environment. We demonstrate that these sensors are typically used in higher concentrations than needed to obtain maximum signal. Exposing cells to either Zn(Zinquin)2 or Zn(TSQ)2 resulted in efficient cellular uptake and the formation of sensor-Zn-protein adducts as evidenced by both a fluorescence spectral shift toward that of ternary adducts and the localization of the fluorescence signal within the proteome after gel filtration of cellular lysates. Likewise, reacting Zn(sensor)2 with the Zn-proteome from LLC-PK1 cells resulted in the formation of sensor-Zn-protein ternary adducts that could be inhibited by first saturating the Zn- proteome with excess sensor. Further, a native SDS-PAGE analysis of the Zn-proteome reacted with either the sensor or the Zn(sensor)2 complex revealed that both reactions result in the formation of a similar set of sensor-Zn-protein fluorescent products. The results of this experiment also demonstrated that TSQ and Zinquin react with different members of the Zn-proteome. Reactions with the model apo-Zn-protein bovine serum albumin showed that both Zn(TSQ)2 and Zn(Zinquin)2 reacted to form ternary adducts with its apo-Zn-binding site. Moreover, incubating Zn(sensor)2 complexes with non-zinc binding proteins failed to elicit a spectral shift in the fluorescence spectrum, supporting the premise that blue-shifted emission spectra are due to sensor-Zn-protein ternary adducts. It was concluded that Zn(sensors)2 species do not play a significant role in the overall reaction between these sensors and

The effects of cetyltrimethylammonium bromide surfactant on alumina modified zinc oxides

Energy Technology Data Exchange (ETDEWEB)

Gac, Wojciech, E-mail: wojciech.gac@umcs.lublin.pl [Department of Chemical Technology, Faculty of Chemistry, Maria Curie-Sklodowska University, 3 M. Curie-Sklodowska Sq., 20-031 Lublin (Poland); Zawadzki, Witold; Słowik, Grzegorz; Pawlonka, Justyna; Machocki, Andrzej [Department of Chemical Technology, Faculty of Chemistry, Maria Curie-Sklodowska University, 3 M. Curie-Sklodowska Sq., 20-031 Lublin (Poland); Lipke, Agnieszka; Majdan, Marek [Department of Inorganic Chemistry, Faculty of Chemistry, Maria Curie-Sklodowska University, 2 M. Curie-Sklodowska Sq., 20-031 Lublin (Poland)

2016-06-15

Highlights: • Synthesis of novel ZnO−Al{sub 2}O{sub 3} oxides in the presence of CTAB surfactant. • Determination of the structural, surface and optical properties. • Nanocrystalline, high-surface area ZnO−Al{sub 2}O{sub 3} oxides. • ZnO-Al{sub 2}O{sub 3} materials of different gap energy. - Abstract: Novel alumina modified zinc oxide materials were prepared by co-precipitation method in the presence of different amounts of cetyltrimethylammonium bromide (CTAB) surfactant. X-ray diffraction, {sup 27}Al magic-angle spinning Nuclear Magnetic Resonance Spectroscopy, and transmission electron microscopy studies evidenced formation of 10–15 nm zinc oxide nanoparticles in the presence of the small amounts of surfactant. Amorphous alumina and zinc aluminate phases of different coordination environment of Al sites were identified. An increase of surfactant concentration led to the elongation of nanoparticles and changes of the nature of hydroxyl groups. Precipitation in the high CTAB concentration conditions facilitated formation of mesoporous materials of high specific surface area. The materials were composed of very small (2–3 nm) zinc aluminate spinel nanoparticles. High concentration of CTAB induced widening of band gap energy.

Synthesis of zinc aluminate with high surface area by microwave hydrothermal method applied in the transesterification of soybean oil (biodiesel)

International Nuclear Information System (INIS)

Quirino, M.R.; Oliveira, M.J.C.; Keyson, D.; Lucena, G.L.; Oliveira, J.B.L.; Gama, L.

2016-01-01

Highlights: • ZnAl_2O_4 spinel was synthesized by the microwave hydrothermal method in only 15 or 30 min. • The powders show high specific surface area. • ZAT_b15 showed activity of 52.22% for the conversion of soybean oil into biodiesel. - Abstract: Zinc aluminate is a material with high thermal stability and high mechanical strength that, owing to these properties, is used as a catalyst or support. In this work, zinc aluminate spinel was synthesized by the microwave hydrothermal method in only 15 or 30 min at a low temperature (150 °C) without templates, using only Al(NO_3)_3·9H_2O, Zn(NO_3)_2·6H_2O, and urea as precursors and applied in the transesterification of soybean oil. X-ray diffraction analysis showed that ZnAl_2O_4 had a cubic structure without secondary phases. The nitrogen adsorption measurements (BET) revealed a high surface area (266.57 m"2 g"−"1) for the nanopowder synthesized in 15 min. This powder showed activity of 52.22% for the catalytic conversion of soybean oil into biodiesel by transesterification.

In-house zinc SAD phasing at Cu Kα edge.

Science.gov (United States)

Kim, Min-Kyu; Lee, Sangmin; An, Young Jun; Jeong, Chang-Sook; Ji, Chang-Jun; Lee, Jin-Won; Cha, Sun-Shin

2013-07-01

De novo zinc single-wavelength anomalous dispersion (Zn-SAD) phasing has been demonstrated with the 1.9 Å resolution data of glucose isomerase and 2.6 Å resolution data of Staphylococcus aureus Fur (SaFur) collected using in-house Cu Kα X-ray source. The successful in-house Zn-SAD phasing of glucose isomerase, based on the anomalous signals of both zinc ions introduced to crystals by soaking and native sulfur atoms, drove us to determine the structure of SaFur, a zinc-containing transcription factor, by Zn-SAD phasing using in-house X-ray source. The abundance of zinc-containing proteins in nature, the easy zinc derivatization of the protein surface, no need of synchrotron access, and the successful experimental phasing with the modest 2.6 Å resolution SAD data indicate that inhouse Zn-SAD phasing can be widely applicable to structure determination.

potentiometric studies of the complexes formed by copper (ii) and zinc

African Journals Online (AJOL)

MBI

, P. M. B. 3011, Kano, Nigeria e-mail: jnaaliya@yahoo.com. ABSTRACT. The overall stability constants of copper (II) and zinc (II) ions with some polar uncharged amino acids including proline, threonine and asparagines were determined by ...

Layered zinc hydroxide–ibuprofen nanohybrids: synthesis and ...

Indian Academy of Sciences (India)

The nonsteroidal anti-inflammatory drug (NSAID), ibuprofen (IBU) anion, was intercalated into the layered zinc ... surface morphology, Fourier transform infrared (FTIR) spectrophotometer to study the chemical interactions and ..... J. Food Sci.

Compartmentation of metals in foliage of Populus tremula grown on soils with mixed contamination. II. Zinc binding inside leaf cell organelles.

Science.gov (United States)

Vollenweider, Pierre; Bernasconi, Petra; Gautschi, Hans-Peter; Menard, Terry; Frey, Beat; Günthardt-Goerg, Madeleine S

2011-01-01

The phytoextraction potential of plants for removing heavy metals from polluted soils is determined by their capacity to store contaminants in aboveground organs and complex them safely. In this study, the metal compartmentation, elemental composition of zinc deposits and zinc complexation within leaves from poplars grown on soil with mixed metal contamination was analysed combining several histochemical and microanalytical approaches. Zinc was the only heavy metal detected and was stored in several organelles in the form of globoid deposits showing β-metachromasy. It was associated to oxygen anions and different cations, noteworthy phosphorous. The deposit structure, elemental composition and element ratios indicated that zinc was chelated by phytic acid ligands. Maturation processes in vacuolar vs. cytoplasmic deposits were suggested by differences in size and amounts of complexed zinc. Hence, zinc complexation by phytate contributed to metal detoxification and accumulation in foliage but could not prevent toxicity reactions therein. Copyright © 2010 Elsevier Ltd. All rights reserved.

Does the oral zinc tolerance test measure zinc absorption

Energy Technology Data Exchange (ETDEWEB)

Valberg, L.S.; Flanagan, P.R.; Brennan, J.; Chamberlain, M.J.

1985-01-01

Increases in plasma zinc concentration were compared with radiozinc absorption after oral test doses. Ten healthy, fasting subjects were each given 385 mumol zinc chloride (25 mg Zn) labelled with 0.5 muCi /sup 65/ZnCl/sub 2/ and a non-absorbed marker, /sup 51/CrCl/sub 3/, dissolved in 100 ml of water; another 10 persons were given 354 mumol zinc chloride and 125 g of minced turkey containing 31 mumol zinc also labelled with /sup 65/Zn and /sup 51/Cr. Measurements were made of plasma zinc concentration at hourly intervals for 5 hours, radiozinc absorption by stool counting of unabsorbed radioactivity 12-36 hours later, and radiozinc retention by whole body counting at 7 days. The mean percentage of radiozinc absorbed and retained in the body from the two test meals was found to be identical (42%). In contrast the increased area under the plasma zinc curve up to 5 hours after the turkey meal, 28 +/- 9 mumol/L (mean +/- SD) was significantly less than that for zinc chloride alone, 47 +/- 15 mumol/L, p less than 0.005. Despite this difference, a good correlation was found between the area under the plasma zinc curve and /sup 65/Zn absorption in individual subjects after each meal. The discrepancy between the results of zinc absorption derived from the plasma zinc curve and /sup 65/Zn absorption for the liquid and solid test meals was most likely explained by binding of zinc to food and delayed gastric emptying of the solid meal. With a test meal of turkey meat at least this dampened the plasma appearance of zinc but did not affect its overall absorption.

Does the oral zinc tolerance test measure zinc absorption

International Nuclear Information System (INIS)

Valberg, L.S.; Flanagan, P.R.; Brennan, J.; Chamberlain, M.J.

1985-01-01

Increases in plasma zinc concentration were compared with radiozinc absorption after oral test doses. Ten healthy, fasting subjects were each given 385 mumol zinc chloride (25 mg Zn) labelled with 0.5 muCi 65 ZnCl 2 and a non-absorbed marker, 51 CrCl 3 , dissolved in 100 ml of water; another 10 persons were given 354 mumol zinc chloride and 125 g of minced turkey containing 31 mumol zinc also labelled with 65 Zn and 51 Cr. Measurements were made of plasma zinc concentration at hourly intervals for 5 hours, radiozinc absorption by stool counting of unabsorbed radioactivity 12-36 hours later, and radiozinc retention by whole body counting at 7 days. The mean percentage of radiozinc absorbed and retained in the body from the two test meals was found to be identical (42%). In contrast the increased area under the plasma zinc curve up to 5 hours after the turkey meal, 28 +/- 9 mumol/L (mean +/- SD) was significantly less than that for zinc chloride alone, 47 +/- 15 mumol/L, p less than 0.005. Despite this difference, a good correlation was found between the area under the plasma zinc curve and 65 Zn absorption in individual subjects after each meal. The discrepancy between the results of zinc absorption derived from the plasma zinc curve and 65 Zn absorption for the liquid and solid test meals was most likely explained by binding of zinc to food and delayed gastric emptying of the solid meal. With a test meal of turkey meat at least this dampened the plasma appearance of zinc but did not affect its overall absorption

Influence of DNA-methylation on zinc homeostasis in myeloid cells: Regulation of zinc transporters and zinc binding proteins.

Science.gov (United States)

Kessels, Jana Elena; Wessels, Inga; Haase, Hajo; Rink, Lothar; Uciechowski, Peter

2016-09-01

The distribution of intracellular zinc, predominantly regulated through zinc transporters and zinc binding proteins, is required to support an efficient immune response. Epigenetic mechanisms such as DNA methylation are involved in the expression of these genes. In demethylation experiments using 5-Aza-2'-deoxycytidine (AZA) increased intracellular (after 24 and 48h) and total cellular zinc levels (after 48h) were observed in the myeloid cell line HL-60. To uncover the mechanisms that cause the disturbed zinc homeostasis after DNA demethylation, the expression of human zinc transporters and zinc binding proteins were investigated. Real time PCR analyses of 14 ZIP (solute-linked carrier (SLC) SLC39A; Zrt/IRT-like protein), and 9 ZnT (SLC30A) zinc transporters revealed significantly enhanced mRNA expression of the zinc importer ZIP1 after AZA treatment. Because ZIP1 protein was also enhanced after AZA treatment, ZIP1 up-regulation might be the mediator of enhanced intracellular zinc levels. The mRNA expression of ZIP14 was decreased, whereas zinc exporter ZnT3 mRNA was also significantly increased; which might be a cellular reaction to compensate elevated zinc levels. An enhanced but not significant chromatin accessibility of ZIP1 promoter region I was detected by chromatin accessibility by real-time PCR (CHART) assays after demethylation. Additionally, DNA demethylation resulted in increased mRNA accumulation of zinc binding proteins metallothionein (MT) and S100A8/S100A9 after 48h. MT mRNA was significantly enhanced after 24h of AZA treatment also suggesting a reaction of the cell to restore zinc homeostasis. These data indicate that DNA methylation is an important epigenetic mechanism affecting zinc binding proteins and transporters, and, therefore, regulating zinc homeostasis in myeloid cells. Copyright © 2016 Elsevier GmbH. All rights reserved.

Nano zinc phosphate coatings for enhanced corrosion resistance of mild steel

International Nuclear Information System (INIS)

Tamilselvi, M.; Kamaraj, P.; Arthanareeswari, M.; Devikala, S.

2015-01-01

Highlights: • Nano zinc phosphate coating on mild steel was developed. • Nano zinc phosphate coatings on mild steel showed enhanced corrosion resistance. • The nano ZnO increases the number of nucleating sites for phosphating. • Faster attainment of steady state during nano zinc phosphating. - Abstract: Nano crystalline zinc phosphate coatings were developed on mild steel surface using nano zinc oxide particles. The chemical composition and morphology of the coatings were analyzed by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The particles size of the nano zinc phosphate coating developed was also characterized by TEM analysis. Potentiodynamic polarization and electrochemical impedance studies were carried out in 3.5% NaCl solution. Significant variations in the coating weight, morphology and corrosion resistance were observed as nano ZnO concentrations were varied from 0.25 to 2 g/L in the phosphating baths. The results showed that nano ZnO particles in the phosphating solution yielded phosphate coatings of higher coating weight, greater surface coverage and enhanced corrosion resistance than the normal zinc phosphate coatings (developed using normal ZnO particles in the phosphating baths). Better corrosion resistance was observed for coatings derived from phosphating bath containing 1.5 g/L nano ZnO. The activation effect brought about by the nano ZnO reduces the amount of accelerator (NaNO 2 ) required for phosphating

The degradation of lining of rotary furnaces in the production of zinc oxide

OpenAIRE

Natália Luptáková; Evgeniy Anisimov; Františka Pešlová

2014-01-01

This paper is closely connected with the complex problem of degradation relating to the refractories of rotary furnace linings in the production of zinc oxide. Zinc oxide can be produced by variety of ways, but the most common method of production which is used in Europe is indirect, i.e. pyrolytic combustion of zinc. This method is also called "French process" of manufacturing ZnO. But this mentioned method of preparation leads to the creation of the enormous amount of zinc slag including ch...

An Aqueous Metal-ion Capacitor with Oxidised Carbon Nanotubes and Metallic Zinc Electrodes

Directory of Open Access Journals (Sweden)

Yuheng Tian

2016-10-01

Full Text Available An aqueous metal ion capacitor comprising of a zinc anode, an oxidized carbon nanotubes (oCNTs cathode and a zinc sulfate electrolyte is reported. Since the shuttling cation is Zn2+, this typical metal ion capacitor is named as zinc-ion capacitor (ZIC. The ZIC integrates the divalent zinc stripping/plating chemistry with the surface-enabled pseudocapacitive cation adsorption/desorption on oCNTs. The surface chemistry and crystallographic structure of oCNTs were extensively characterized by combining X-ray photoelectron spectroscopy, Fourier-transformed infrared spectroscopy, Raman spectroscopy and X-ray powder diffraction. The function of the surface oxygen groups in surface cation storage was elucidated by a series of electrochemical measurement and the surface-enabled ZIC showed better performance than the ZIC with an un-oxidized CNT cathode. The reaction mechanism at the oCNT cathode involves the additional reversible Faradaic process, while the CNTs merely show electric double layer capacitive behavior involving a non-Faradaic process. The aqueous hybrid ZIC comprising the oCNT cathode exhibited a specific capacitance of 20 mF cm-2 (corresponding to 53 F g-1 in the range of 0-1.8 V at 10 mV s-1 and a stable cycling performance up to 5000 cycles.

An Aqueous Metal-Ion Capacitor with Oxidized Carbon Nanotubes and Metallic Zinc Electrodes

Energy Technology Data Exchange (ETDEWEB)

Tian, Yuheng; Amal, Rose; Wang, Da-Wei, E-mail: da-wei.wang@unsw.edu.au [School of Chemical Engineering, The University of New South Wales (UNSW), Sydney, NSW (Australia)

2016-10-03

An aqueous metal ion capacitor comprising of a zinc anode, oxidized carbon nanotubes (oCNTs) cathode, and a zinc sulfate electrolyte is reported. Since the shuttling cation is Zn{sup 2+}, this typical metal ion capacitor is named as zinc-ion capacitor (ZIC). The ZIC integrates the divalent zinc stripping/plating chemistry with the surface-enabled pseudocapacitive cation adsorption/desorption on oCNTs. The surface chemistry and crystallographic structure of oCNTs were extensively characterized by combining X-ray photoelectron spectroscopy, Fourier-transformed infrared spectroscopy, Raman spectroscopy, and X-ray powder diffraction. The function of the surface oxygen groups in surface cation storage was elucidated by a series of electrochemical measurement and the surface-enabled ZIC showed better performance than the ZIC with an un-oxidized CNT cathode. The reaction mechanism at the oCNT cathode involves the additional reversible Faradaic process, while the CNTs merely show electric double layer capacitive behavior involving a non-Faradaic process. The aqueous hybrid ZIC comprising the oCNT cathode exhibited a specific capacitance of 20 mF cm{sup −2} (corresponding to 53 F g{sup −1}) in the range of 0–1.8 V at 10 mV s{sup −1} and a stable cycling performance up to 5000 cycles.

Distribution of zinc-65 in Agrostis tenuis Sibth. and A. stolonifera L. tissues

Energy Technology Data Exchange (ETDEWEB)

Peterson, P J

1969-11-01

The distribution of /sup 65/Zn in zinc-tolerant and copper-tolerant plants of Agrotis spp. from toxic mine-tailings in England and Wales was compared with zinc distribution in non-tolerant plants. Isotope was applied in culture solution in which the plants were growing. No differences could be demonstrated between the plants by whole-plant radioautography, or by zinc analyses of the tops. Root/shoot ratios calculated from specific activity values varied with population, the non-tolerant plants having the lowest and the zinc-tolerant plants the highest ratio. After solvent (80% ethanol and water) extractions, the root residue of zinc-tolerant plants contained a higher percentage of /sup 65/Zn than that of non-tolerant plants. Chemical fractionation of the roots revealed that the main difference was that the amount of /sup 65/Zn in the pectate extract of the cell wall was high in zinc-tolerant plants and low in non-tolerant plants. The /sup 65/Zn distribution in the copper-tolerant plants was similar to that in the non-tolerant plants, indicating that the tolerance mechanisms for the two elements are different. Soluble protein and RNA preparations were made but they contained low levels of /sup 65/Zn. An exception was the relatively high value for RNA from zinc-tolerant A. stolonifera shoots. An anionic complex of /sup 65/Zn in the soluble fraction was investigated. This complex accounted for most of the radioactivity in A. tenuis extracts of shoots but the concentration of the complex was low in A. stolonifera shoots, and in root extracts of all plants examined. 18 references, 2 figures, 4 tables.

New Route to Synthesize Surface Organometallic Complexes (SOMC): An Approach by Alkylating Halogenated Surface Organometallic Fragments

KAUST Repository

Hamieh, Ali Imad Ali

2017-01-01

The aim of this thesis is to explore new simpler and efficient routes for the preparation of surface organometallic complexes (SOMC) for the transformation of small organic molecules to valuable products. The key element in this new route relies on surface alkylation of various halogenated surface coordination complexes or organometallic fragments (SOMF).

New Route to Synthesize Surface Organometallic Complexes (SOMC): An Approach by Alkylating Halogenated Surface Organometallic Fragments

KAUST Repository

Hamieh, Ali Imad

2017-02-01

The aim of this thesis is to explore new simpler and efficient routes for the preparation of surface organometallic complexes (SOMC) for the transformation of small organic molecules to valuable products. The key element in this new route relies on surface alkylation of various halogenated surface coordination complexes or organometallic fragments (SOMF).

Method of capturing or trapping zinc using zinc getter materials

Science.gov (United States)

Hunyadi Murph, Simona E.; Korinko, Paul S.

2017-07-11

A method of trapping or capturing zinc is disclosed. In particular, the method comprises a step of contacting a zinc vapor with a zinc getter material. The zinc getter material comprises nanoparticles and a metal substrate.

The Effect of Ductile Cast Iron Matrix on Zinc Coating During Hot Dip Galvanising of Castings

Directory of Open Access Journals (Sweden)

D. Kopyciński

2012-12-01

Full Text Available The growth kinetics of the zinc coating formed on the surface of casting made from ductile iron grade EN-GJS-500-3 was investigated. To produce homogenous metal matrix in test samples, the normalising and ferritising annealing was carried out. Studies showeda heterogeneous structure of cast iron with varying content of the phases formed. This was followed by hot dip galvanising treatment at450°C to capture the growth kinetics of the zinc coating (the time of the treatment ranged from 60 to 600 seconds. Nonlinear estimation of the determined growth kinetics of the alloyed layer of a zinc coating was made and an equation of the zinc coating growth was derived.Based on the results of the investigations it was concluded that thickness of the zinc coating formed on the surface of casting with a 100% pearlitic matrix makes 55% of the thickness of coating formed on the surface in 100% ferritic.

The Effect of Ductile Cast Iron Matrix on Zinc Coating During Hot Dip Galvanising of Castings

Directory of Open Access Journals (Sweden)

Kopyciński D.

2012-12-01

Full Text Available The growth kinetics of the zinc coating formed on the surface of casting made from ductile iron grade EN-GJS-500-3 was investigated. To produce homogenous metal matrix in test samples, the normalising and ferritising annealing was carried out. Studies showed a heterogeneous structure of cast iron with varying content of the phases formed. This was followed by hot dip galvanising treatment at 450°C to capture the growth kinetics of the zinc coating (the time of the treatment ranged from 60 to 600 seconds. Nonlinear estimation of the determined growth kinetics of the alloyed layer of a zinc coating was made and an equation of the zinc coating growth was derived. Based on the results of the investigations it was concluded that thickness of the zinc coating formed on the surface of casting with a 100% pearlitic matrix makes 55% of the thickness of coating formed on the surface in 100% ferritic.

Surface ligand dependent toxicity of zinc oxide nanoparticles in HepG2 cell model

International Nuclear Information System (INIS)

Bartczak, D; Baradez, M-O; Merson, S; Goenaga-Infante, H; Marshall, D

2013-01-01

Physicochemical properties of nanoparticles (NP) strongly affect their influence on cell behaviour, but can be significantly distorted by interactions with the proteins present in biological solutions. In this study we show how different surface functionalities of zinc oxide (ZnO) NP lead to changes in the size distribution and dissolution of the NP in serum containing cell culture media and how this impacts on NP toxicity. NPs capped with weakly bound large proteins undergo substantial transformations due to the exchange of the original surface ligands to the components of the cell culture media. Conversely, NP capped with a tight monolayer of small organic molecules or with covalently conjugated proteins show significantly higher stability. These differences in ligand exchange also affect the toxicity of the NP to the HepG2 liver cell model, with the NP capped with small organic molecules being more toxic than those capped with large proteins. This study highlights the importance of characterising NPs in biological media and the effect the media has during in-vitro analysis.

Cobalt (III) complexes as novel matrix metalloproteinase-9 inhibitors

International Nuclear Information System (INIS)

Lee, Jiyoun

2012-01-01

We have synthesized a series of novel MMP-9 inhibitors containing cobalt(III) complexes. The synthesized cobalt(III) complexes are effective as enzyme inhibitors and the attachment of a biphenyl group enhanced the efficiency of enzyme inhibition up to 6-fold. When compared to the reported non-hydroxamate MMP inhibitors, the synthesized complexes showed comparable in vitro potency. The enzyme assay showed that the cobalt(III) complex can disrupt the zinc binding active site of MMP-9 and is proposed to work via a ligand exchange mechanism. Since histidine residues are essential for the catalytic activity of a large percentage of enzymes and zinc finger proteins, these cobalt(III) complexes can serve as a prototype inhibitor towards various zinc containing enzymes and proteins. Matrix metalloproteinases (MMPs) are a family of zinc binding endopeptidases that play crucial roles in various physiological processes and diseases such as embryogenic growth, angiogenesis, arthritis, skin ulceration, liver fibrosis and tumor metastasis. Because of their implications in a wide range of diseases, MMPs are considered as intriguing drug targets. The majority of MMP inhibitors are organic small molecules containing a hydroxamate functionality for the zinc binding group. This hydroxamate group binds to a zinc(II) center in a bidentate fashion and creates a distorted trigonal bipyramidal geometry

Cobalt (III) complexes as novel matrix metalloproteinase-9 inhibitors

Energy Technology Data Exchange (ETDEWEB)

Lee, Jiyoun [Sungshin Women' s Univ., Seoul (Korea, Republic of)

2012-04-15

We have synthesized a series of novel MMP-9 inhibitors containing cobalt(III) complexes. The synthesized cobalt(III) complexes are effective as enzyme inhibitors and the attachment of a biphenyl group enhanced the efficiency of enzyme inhibition up to 6-fold. When compared to the reported non-hydroxamate MMP inhibitors, the synthesized complexes showed comparable in vitro potency. The enzyme assay showed that the cobalt(III) complex can disrupt the zinc binding active site of MMP-9 and is proposed to work via a ligand exchange mechanism. Since histidine residues are essential for the catalytic activity of a large percentage of enzymes and zinc finger proteins, these cobalt(III) complexes can serve as a prototype inhibitor towards various zinc containing enzymes and proteins. Matrix metalloproteinases (MMPs) are a family of zinc binding endopeptidases that play crucial roles in various physiological processes and diseases such as embryogenic growth, angiogenesis, arthritis, skin ulceration, liver fibrosis and tumor metastasis. Because of their implications in a wide range of diseases, MMPs are considered as intriguing drug targets. The majority of MMP inhibitors are organic small molecules containing a hydroxamate functionality for the zinc binding group. This hydroxamate group binds to a zinc(II) center in a bidentate fashion and creates a distorted trigonal bipyramidal geometry.

Zinc in soybeans. Chemical nature and bioavilability

International Nuclear Information System (INIS)

Khan, A.

1987-01-01

Soybeans were grown hydroponically and intrinsically labeled with 65 Zn through root absorption, stem injection and foliar application. Stem injection resulted in the greatest accumulation of 65 Zn. Regardless of the labeling technique, approximately 40-45% of the seed 65 Zn was associated with the subcellular organelles. The pattern of 65 Zn incorporation into soybeans did not change appreciably as a result of the labelling technique. The major portion of the soluble 65 Zn was either free or associated with very low molecular weight proteins, peptides, or their complexes with phytic acid rather than the major proteins of soybeans. Zinc in soybeans is ionically bound to proteins, peptides and phytic acid. Autoclaving did not affect the chemical association of zinc with soy proteins. Solubility of protein, zinc and phytic acid was studied over the pH range of 3.5-12.0. Bioavailability of zinc to rats from soybeans was lower than from casein and rats adapted to a casein basal diet absorbed more 65 Zn from both casein and soy than rats adapted to a soy basal diet

Analysis of reaction and transport processes in zinc air batteries

CERN Document Server

Schröder, Daniel

2016-01-01

This book contains a novel combination of experimental and model-based investigations, elucidating the complex processes inside zinc air batteries. The work presented helps to answer which battery composition and which air-composition should be adjusted to maintain stable and efficient charge/discharge cycling. In detail, electrochemical investigations and X-ray transmission tomography are applied on button cell zinc air batteries and in-house set-ups. Moreover, model-based investigations of the battery anode and the impact of relative humidity, active operation, carbon dioxide and oxygen on zinc air battery operation are presented. The techniques used in this work complement each other well and yield an unprecedented understanding of zinc air batteries. The methods applied are adaptable and can potentially be applied to gain further understanding of other metal air batteries. Contents Introduction on Zinc Air Batteries Characterizing Reaction and Transport Processes Identifying Factors for Long-Term Stable O...

Process Optimization of EDM Cutting Process on Tool Steel using Zinc Coated Electrode

Directory of Open Access Journals (Sweden)

Hanizam H.

2017-01-01

Full Text Available In WEDM machining process, surface finish quality depends on intensity and duration of spark plasma. Electrode wire diameter has significant effect on the spark intensity and yet the studies on this matter still less. Therefore, the main objectives of this studies are to compare the different diameters of zinc coated and uncoated brass electrode on H13 tool steel surface roughness. The experiments were conducted on Sodick VZ300L WEDM and work piece material of tool steel AISI H13 block. Electrode of zinc coated brass with diameters of 0.1 mm, 0.2 mm, 0.25 mm and uncoated brass 0.2 mm were used. The surface roughness of cutting was measured using the SUR-FTEST SJ-410 Mitutoyo, surface roughness tester. The results suggest that better surface roughness quality can be achieved through smaller electrode wire diameter. The zinc coated improves flushing ability and sparks intensity resulting in better surface finish of H13 tool steel. New alloys and coating materials shall be experimented to optimized the process further.

Uranium(VI) sorption onto magnetite. Increasing confidence in surface complexation models using chemically evident surface chemistry

Energy Technology Data Exchange (ETDEWEB)

Bok, Frank [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes

2017-06-01

Surface complexation models have made great efforts in describing the sorption of various radionuclides on naturally occurring mineral phases. Unfortunately, many of the published sorption parameter sets are built upon unrealistic or even wrong surface chemistry. This work describes the benefit of combining spectroscopic and batch sorption experimental data to create a reliable and consistent surface complexation parameter set.

Role of nanoparticles in phase separation and final morphology of superhydrophobic polypropylene/zinc oxide nanocomposite surfaces

Energy Technology Data Exchange (ETDEWEB)

Hejazi, Iman [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Hajalizadeh, Bardia [Department of Chemical Engineering, Islamic Azad University, Shahrood Branch, P.O. Box 36155-163, Shahrood (Iran, Islamic Republic of); Seyfi, Javad, E-mail: Jseyfi@gmail.com [Department of Chemical Engineering, Islamic Azad University, Shahrood Branch, P.O. Box 36155-163, Shahrood (Iran, Islamic Republic of); Sadeghi, Gity Mir Mohamad [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Jafari, Seyed-Hassan [School of Chemical Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Khonakdar, Hossein Ali [Iran Polymer and Petrochemical Institute, P.O. Box 14965/115, Tehran (Iran, Islamic Republic of)

2014-02-28

In this work, phase separation process was revisited to study the effect of nanoparticles in acceleration of phase separation and formation of hierarchical structures. Superhydrophobic surfaces were prepared using polypropylene (PP) and the corresponding nanocomposites containing zinc oxide (ZnO) nanoparticles through a typical solution casting method. The wettability and morphological behavior of the surfaces were investigated via water contact angle (WCA) measurements and scanning electron microscopy (SEM), respectively. It was found that upon introduction of ZnO nanoparticles into the pure PP, the obtained surfaces have become superhydrophobic with WCAs above 150° and sliding angles below 10°. Calcination of ZnO nanoparticles was exploited to explicate the unexpected significant loss in superhydrophobicity of the sample loaded with high ZnO content. Crystallization behavior of the samples were also investigated via differential scanning calorimetry and correlated to superhydrophobicity of the surfaces. X-ray photoelectron and Fourier transform infrared spectroscopies were also utilized to further characterize the samples. An attempt was also made to present a more clear mechanism for formation of hierarchical structures which are responsible for superhydrophobicity. Likewise, the so far proposed mechanisms for formation of micro/nano roughness on the superhydrophobic surfaces were reviewed as well.

The bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens

OpenAIRE

Veldkamp, T.; Diepen, van, J.T.M.; Bikker, P.

2014-01-01

Zinc is an essential trace element for all farm animal species. It is commonly included in animal diets as zinc oxide, zinc sulphate or organically bound zinc. Umicore Zinc Chemicals developed zinc oxide products with different mean particle sizes. Umicore Zinc Chemicals requested Wageningen UR Livestock Research to determine the bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens. A precise estimate of the bioavailability of zinc sources is required both for fulf...

The effect of the electrode material on the electrodeposition of zinc from deep eutectic solvents

International Nuclear Information System (INIS)

Vieira, L.; Schennach, R.; Gollas, B.

2016-01-01

Highlights: • Mechanistic insight into zinc electrodeposition from deep eutectic solvents. • Overpotential for hydrogen evolution affects the electrodeposition of zinc. • Electrodeposited zinc forms surface alloys on Cu, Au, and Pt. • In situ PM-IRRAS of a ZnCl_2 containing deep eutectic solvent on glassy carbon. - Abstract: The voltammetric behaviour of the ZnCl_2 containing deep eutectic solvent choline chloride/ethylene glycol 1:2 was investigated on glassy carbon, stainless steel, Au, Pt, Cu, and Zn electrodes. While cyclic voltammetry on glassy carbon and stainless steel showed a cathodic peak for zinc electrodeposition only in the anodic reverse sweep, a cathodic peak was found also in the cathodic forward sweep on Au, Pt, Cu, and Zn. This behaviour is in agreement with the proposed mechanism of zinc deposition from an intermediate species Z, whose formation depends on the cathodic reduction potential of the solvent. The voltammetric reduction of the electrolyte involves hydrogen evolution and as a result the formation of Z and its reduction to zinc depend on the hydrogen overpotential for each electrode material. On Au, Pt, and Cu also the anodic stripping was different from that on glassy carbon and steel due to the formation of surface zinc alloys with the three former metals. The morphology of the zinc layers on Cu has been characterised by scanning electron microscopy and focussed ion beam. X-ray diffraction confirmed the presence of crystalline zinc and a Cu_4Zn phase. Spectroelectrochemistry by means of polarization modulation reflection-absorption spectroscopy (PM-IRRAS) on a glassy carbon electrode in the ZnCl_2 containing deep eutectic solvent showed characteristic potential dependent changes. The variation of band intensities at different applied potentials correlate with the voltammetry and suggest the formation of a compact blocking layer on the electrode surface, which inhibits the electrodeposition of zinc at sufficiently negative

Application of zinc isotope tracer technology in tracing soil heavy metal pollution

Science.gov (United States)

Norbu, Namkha; Wang, Shuguang; Xu, Yan; Yang, Jianqiang; Liu, Qiang

2017-08-01

Recent years the soil heavy metal pollution has become increasingly serious, especially the zinc pollution. Due to the complexity of this problem, in order to prevent and treat the soil pollution, it's crucial to accurately and quickly find out the pollution sources and control them. With the development of stable isotope tracer technology, it's able to determine the composition of zinc isotope. Based on the theory of zinc isotope tracer technique, and by means of doing some latest domestic and overseas literature research about the zinc isotope multi-receiving cups of inductively coupled plasma mass spectrometer (MC-ICP-MS) testing technology, this paper summarized the latest research results about the pollution tracer of zinc isotope, and according to the deficiencies and existing problems of previous research, made outlooks of zinc isotope fractionation mechanism, repository establishment and tracer multiple solutions.

Zinc corrosion after loss-of-coolant accidents in pressurized water reactors – Physicochemical effects

Energy Technology Data Exchange (ETDEWEB)

Kryk, Holger, E-mail: h.kryk@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Fluid Dynamics, P.O. Box 510119, D-01314 Dresden (Germany); Hoffmann, Wolfgang [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Fluid Dynamics, P.O. Box 510119, D-01314 Dresden (Germany); Kästner, Wolfgang; Alt, Sören; Seeliger, André; Renger, Stefan [Hochschule Zittau/Görlitz, Institute of Process Technology, Process Automation and Measuring Technology, Theodor-Körner-Allee 16, D-02763 Zittau (Germany)

2014-12-15

Highlights: • Physicochemical effects due to post-LOCA zinc corrosion in PWR were elucidated. • Decreasing solubility of corrosion products with increasing temperature was found. • Solid corrosion products may be deposited on hot surfaces and/or within hot-spots. • Corrosion products precipitating from coolant were identified as zinc borates. • Depending on coolant temperature, different types of zinc borate are formed. - Abstract: Within the framework of the reactor safety research, generic experimental investigations were carried out aiming at the physicochemical background of possible zinc corrosion product formation, which may occur inside the reactor pressure vessel during the sump circulation operation after loss-of-coolant accidents in pressurized water reactors. The contact of the boric acid containing coolant with hot-dip galvanized steel containment internals causes corrosion of the corresponding materials resulting in dissolution of the zinc coat. A retrograde solubility of zinc corrosion products with increasing temperature was observed during batch experiments of zinc corrosion in boric acid containing coolants. Thus, the formation and deposition of solid corrosion products cannot be ruled out if the coolant containing dissolved zinc is heated up during its recirculation into hot regions within the emergency cooling circuit (e.g. hot-spots in the core). Corrosion experiments at a lab-scale test facility, which included formation of corrosion products at a single heated cladding tube, proved that dissolved zinc, formed at low temperatures in boric acid solution by zinc corrosion, turns into solid deposits of zinc borates when contacting heated zircaloy surfaces during the heating of the coolant. Moreover, the temperature of formation influences the chemical composition of the zinc borates and thus the deposition and mobilization behavior of the products.

Zinc corrosion after loss-of-coolant accidents in pressurized water reactors – Physicochemical effects

International Nuclear Information System (INIS)

Kryk, Holger; Hoffmann, Wolfgang; Kästner, Wolfgang; Alt, Sören; Seeliger, André; Renger, Stefan

2014-01-01

Highlights: • Physicochemical effects due to post-LOCA zinc corrosion in PWR were elucidated. • Decreasing solubility of corrosion products with increasing temperature was found. • Solid corrosion products may be deposited on hot surfaces and/or within hot-spots. • Corrosion products precipitating from coolant were identified as zinc borates. • Depending on coolant temperature, different types of zinc borate are formed. - Abstract: Within the framework of the reactor safety research, generic experimental investigations were carried out aiming at the physicochemical background of possible zinc corrosion product formation, which may occur inside the reactor pressure vessel during the sump circulation operation after loss-of-coolant accidents in pressurized water reactors. The contact of the boric acid containing coolant with hot-dip galvanized steel containment internals causes corrosion of the corresponding materials resulting in dissolution of the zinc coat. A retrograde solubility of zinc corrosion products with increasing temperature was observed during batch experiments of zinc corrosion in boric acid containing coolants. Thus, the formation and deposition of solid corrosion products cannot be ruled out if the coolant containing dissolved zinc is heated up during its recirculation into hot regions within the emergency cooling circuit (e.g. hot-spots in the core). Corrosion experiments at a lab-scale test facility, which included formation of corrosion products at a single heated cladding tube, proved that dissolved zinc, formed at low temperatures in boric acid solution by zinc corrosion, turns into solid deposits of zinc borates when contacting heated zircaloy surfaces during the heating of the coolant. Moreover, the temperature of formation influences the chemical composition of the zinc borates and thus the deposition and mobilization behavior of the products

Solving complex and disordered surface structures with electron diffraction

International Nuclear Information System (INIS)

Van Hove, M.A.

1987-10-01

The past of surface structure determination with low-energy electron diffraction (LEED) will be briefly reviewed, setting the stage for a discussion of recent and future developments. The aim of these developments is to solve complex and disordered surface structures. Some efficient solutions to the theoretical and experimental problems will be presented. Since the theoretical problems dominate, the emphasis will be on theoretical approaches to the calculation of the multiple scattering of electrons through complex and disordered surfaces. 49 refs., 13 figs., 1 tab

Characterization of surface complexes in enhanced Raman scattering

International Nuclear Information System (INIS)

Roy, D.; Furtak, T.E.

1984-01-01

An indicator molecule, para-nitrosodimethylanaline (p-NDMA), has been used to study the chemical nature of surface complexes involving the active site for SERS in the electrochemical environment. We present evidence for positively charged Ag atoms stabilized by coadsorbed Cl - ions as the primary sites which are produced during the oxidation reduction cycle treatment of an Ag electrode. Depending on the relative number of Cl - ions which influence the Ag site the active site demonstrates a greater or lesser electron accepting character toward p-NDMA. This character is influenced by the applied voltage and by the presence of Tl + ions in the bulk of the solution near the surface. As in previously studied systems p-NDMA/Cl - /Ag complexes demonstrate charge transfer excitation which in this case is from the p-NDMA to the Ag site. These results further solidify the importance of complex formation in electrochemical SERS and suggest that caution should be applied when using SERS as a quantitative measure of surface coverage

Study of silicon doped with zinc ions and annealed in oxygen

International Nuclear Information System (INIS)

Privezentsev, V. V.; Kirilenko, E. P.; Goryachev, A. N.; Batrakov, A. A.

2017-01-01

The results of studies of the surface layer of silicon and the formation of precipitates in Czochralski n-Si (100) samples implanted with "6"4Zn"+ ions with an energy of 50 keV and a dose of 5 × 10"1"6 cm"–"2 at room temperature and then oxidized at temperatures from 400 to 900°C are reported. The surface is visualized using an electron microscope, while visualization of the surface layer is conducted via profiling in depth by elemental mapping using Auger electron spectroscopy. The distribution of impurity ions in silicon is analyzed using a time-of-flight secondary-ion mass spectrometer. Using X-ray photoelectron spectroscopy, the chemical state of atoms of the silicon matrix and zinc and oxygen impurity atoms is studied, and the phase composition of the implanted and annealed samples is refined. After the implantation of zinc, two maxima of the zinc concentration, one at the wafer surface and the other at a depth of 70 nm, are observed. In this case, nanoparticles of the Zn metal phase and ZnO phase, about 10 nm in dimensions, are formed at the surface and in the surface layer. After annealing in oxygen, the ZnO · Zn_2SiO_4 and Zn · ZnO phases are detected near the surface and at a depth of 50 nm, respectively.

Relation between microstructure and adhesion of hot dip galvanized zinc coatings on dual phase steel

International Nuclear Information System (INIS)

Song, G.M.; Vystavel, T.; Pers, N. van der; De Hosson, J.Th.M.; Sloof, W.G.

2012-01-01

Highlights: ► Amorphous manganese oxides present at the steel surface impair the adhesion of the zinc coating. ► The adhesion of the various interfaces that exist in zinc coated steel is quantitatively estimated using the “Macroscopic Atom” model. ► Zinc coating delaminates along the zinc layer/inhibition layer and ζ-FeZn 13 particle/inhibition layer interfaces, which agrees the theoretical calculation. - Abstract: The microstructure of hot dip galvanized zinc coatings on dual phase steel was investigated by electron microscopy and the coating adhesion characterized by tensile testing. The zinc coating consists of a zinc layer and columnar ζ-FeZn 13 particles on top of a thin inhibition layer adjacent to the steel substrate. The inhibition layer is a thin compact and continuous layer that consists of η-Fe 2 Al 5–x Zn x fine and coarse particles. The coarse faceted particles are on top and fine faceted particles are at the bottom. The steel surface is covered with small fraction manganese oxides, which may impair adhesion of the zinc coating. The adhesion at various interfaces that exist in zinc-coated steel was quantitatively estimated using a so-called “macroscopic atom” model. In addition, the adhesion at the interfaces in zinc-coated steel was qualitatively assessed by examining the fracture and delamination behavior upon tensile testing. In accordance with this model, fracture along zinc grain boundaries preceded fracture along the zinc layer/inhibition layer and ζ-FeZn 13 particle/inhibition layer interfaces.

The bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens

NARCIS (Netherlands)

Veldkamp, T.; Diepen, van J.T.M.; Bikker, P.

2014-01-01

Zinc is an essential trace element for all farm animal species. It is commonly included in animal diets as zinc oxide, zinc sulphate or organically bound zinc. Umicore Zinc Chemicals developed zinc oxide products with different mean particle sizes. Umicore Zinc Chemicals requested Wageningen UR

Synthesis, thermal, spectral and biological properties of zinc(II) 4-hydroxybenzoate complexes

Czech Academy of Sciences Publication Activity Database

Homzová, K.; Györyová, K.; Bujdošová, Z.; Hudecová, D.; Ganajová, M.; Vargová, Z.; Kovářová, Jana

2014-01-01

Roč. 116, č. 1 (2014), s. 77-91 ISSN 1388-6150 Institutional support: RVO:61389013 Keywords : zinc * 4-hydroxybenzoate * thermal Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.042, year: 2014

Mechanism and degradation kinetics of zinc complex containing isophthalato and 2,2‧-dipyridylamine ligands under different atmospheres

Science.gov (United States)

Zdravković, J. D.; Radovanović, L.; Poleti, D.; Rogan, J. R.; Vulić, P. J.; Radovanović, Ž.; Minić, D. M.

2018-06-01

The design of mixed-ligand complexes are of increasing interest from fundamental as well as technological and curative aspects. Having that in mind, we studied zinc complex containing 2,2‧-dipyridylamine (dipya) and dianion of isophthalic acid (ipht), [Zn(dipya)(ipht)]n, as promising precursor for synthesis of nanostructured metal oxide. In that sense, the mechanism and degradation kinetics of [Zn(dipya)(ipht)]n was analyzed under non-isothermal conditions in nitrogen and in air atmospheres. Peak deconvolution of the [Zn(dipya)(ipht)]n decomposition profile, in the form of a derivative thermogram (DTG), in nitrogen atmosphere, revealed the presence of three decomposition steps, while in air five single steps were isolated. In both cases ZnO is formed as residue at 530 °C: pure (in air) or in amorphous matrix (nitrogen). In air we obtained well crystalized ZnO nanospheres (∼25 nm), by thermal treatment in temperature range 370-530 °C showing that this complex could be considered as good precursor for production of nanosized ZnO.

Mobile trap algorithm for zinc detection using protein sensors

International Nuclear Information System (INIS)

Inamdar, Munish V.; Lastoskie, Christian M.; Fierke, Carol A.; Sastry, Ann Marie

2007-01-01

We present a mobile trap algorithm to sense zinc ions using protein-based sensors such as carbonic anhydrase (CA). Zinc is an essential biometal required for mammalian cellular functions although its intracellular concentration is reported to be very low. Protein-based sensors like CA molecules are employed to sense rare species like zinc ions. In this study, the zinc ions are mobile targets, which are sought by the mobile traps in the form of sensors. Particle motions are modeled using random walk along with the first passage technique for efficient simulations. The association reaction between sensors and ions is incorporated using a probability (p 1 ) upon an ion-sensor collision. The dissociation reaction of an ion-bound CA molecule is modeled using a second, independent probability (p 2 ). The results of the algorithm are verified against the traditional simulation techniques (e.g., Gillespie's algorithm). This study demonstrates that individual sensor molecules can be characterized using the probability pair (p 1 ,p 2 ), which, in turn, is linked to the system level chemical kinetic constants, k on and k off . Further investigations of CA-Zn reaction using the mobile trap algorithm show that when the diffusivity of zinc ions approaches that of sensor molecules, the reaction data obtained using the static trap assumption differ from the reaction data obtained using the mobile trap formulation. This study also reveals similar behavior when the sensor molecule has higher dissociation constant. In both the cases, the reaction data obtained using the static trap formulation reach equilibrium at a higher number of complex molecules (ion-bound sensor molecules) compared to the reaction data from the mobile trap formulation. With practical limitations on the number sensors that can be inserted/expressed in a cell and stochastic nature of the intracellular ionic concentrations, fluorescence from the number of complex sensor molecules at equilibrium will be the measure

Synthesis of zinc aluminate with high surface area by microwave hydrothermal method applied in the transesterification of soybean oil (biodiesel)

Energy Technology Data Exchange (ETDEWEB)

Quirino, M.R. [Chemistry Laboratory of Federal University of Paraiba (LABQUIM), Campus III, 58200-000 Bananeiras, PB (Brazil); Oliveira, M.J.C. [Academic Unit of Materials Engineering, UFCG, Campina Grande Campus I, 58429-900 Campina Grande, PB (Brazil); Keyson, D. [Laboratory of study in Science, DME, Federal University of Paraíba, Campus I, 58051-900 João Pessoa, PB (Brazil); Lucena, G.L., E-mail: guilherme_leo1@yahoo.com.br [Chemistry Laboratory of Federal University of Paraiba (LABQUIM), Campus III, 58200-000 Bananeiras, PB (Brazil); Oliveira, J.B.L. [Federal University of Rio Grande do Norte, UFRN, Campus I, 59078-970 Natal, RN (Brazil); Gama, L. [Academic Unit of Materials Engineering, UFCG, Campina Grande Campus I, 58429-900 Campina Grande, PB (Brazil)

2016-02-15

Highlights: • ZnAl{sub 2}O{sub 4} spinel was synthesized by the microwave hydrothermal method in only 15 or 30 min. • The powders show high specific surface area. • ZAT{sub b}15 showed activity of 52.22% for the conversion of soybean oil into biodiesel. - Abstract: Zinc aluminate is a material with high thermal stability and high mechanical strength that, owing to these properties, is used as a catalyst or support. In this work, zinc aluminate spinel was synthesized by the microwave hydrothermal method in only 15 or 30 min at a low temperature (150 °C) without templates, using only Al(NO{sub 3}){sub 3}·9H{sub 2}O, Zn(NO{sub 3}){sub 2}·6H{sub 2}O, and urea as precursors and applied in the transesterification of soybean oil. X-ray diffraction analysis showed that ZnAl{sub 2}O{sub 4} had a cubic structure without secondary phases. The nitrogen adsorption measurements (BET) revealed a high surface area (266.57 m{sup 2} g{sup −1}) for the nanopowder synthesized in 15 min. This powder showed activity of 52.22% for the catalytic conversion of soybean oil into biodiesel by transesterification.

Solution NMR characterization of Sgf73(1-104) indicates that Zn ion is required to stabilize zinc finger motif

International Nuclear Information System (INIS)

Lai, Chaohua; Wu, Minhao; Li, Pan; Shi, Chaowei; Tian, Changlin; Zang, Jianye

2010-01-01

Zinc finger motif contains a zinc ion coordinated by several conserved amino acid residues. Yeast Sgf73 protein was identified as a component of SAGA (Spt/Ada/Gcn5 acetyltransferase) multi-subunit complex and Sgf73 protein was known to contain two zinc finger motifs. Sgf73(1-104), containing the first zinc finger motif, was necessary to modulate the deubiquitinase activity of SAGA complex. Here, Sgf73(1-104) was over-expressed using bacterial expression system and purified for solution NMR (nuclear magnetic resonance) structural studies. Secondary structure and site-specific relaxation analysis of Sgf73(1-104) were achieved after solution NMR backbone assignment. Solution NMR and circular dichroism analysis of Sgf73(1-104) after zinc ion removal using chelation reagent EDTA (ethylene-diamine-tetraacetic acid) demonstrated that zinc ion was required to maintain stable conformation of the zinc finger motif.

Synthesis and characterization of monomeric and dimeric manganese(II and zinc(II complexes of pyridine-2-carbaldoxime

Directory of Open Access Journals (Sweden)

Jørgen Glerup

2000-12-01

Full Text Available The syntheses and characterization of two complexes of manganese(II and one complex of zinc(II with the ligand pyridine-2-carbaldoxime, C6H6N2O, are described. The monomeric manganese(II complex cis-[Mn(C6H6N2O 2Cl2] (1 crystallizes in the orthorhombic space group Pbcn with 4 formula units in a cell of dimensions a = 12.479(3 Å, b = 10.348(2 Å, and c = 11. 974(2 Å. The structure has been refined to a final value of the conventional R-factor of 0.0330 based on 1513 observed independent reflections. The analogous zinc(II complex, cis-[Zn(C6H6N2O2Cl2] (2 also crystallizes in the orthorhombic space group Pbcn with 4 formula units in a cell of dimensions a = 12.215(2 Å, b = 10.383(2 Å, and c = 12. 016(2 Å. The structure has been refined to a final value of the conventional R-factor of 0.0377 based on 1117 observed independent reflections. The two complexes are isostructural, with the central metal atom lying on a crystallographic 2-fold axis. Both complexes are approximately octahedral, the coordination being provided by two trans pyridine nitrogen atoms and two cis amine nitrogen atoms from the oxime ligands, and by two cis chlorides. The dimeric manganese(II complex [(C6H6N2O(CH3OHClMnCl2MnCl(CH3OH(C6H6N2O] (3 crystallizes in the monoclinic space group P21/n with 2 formula units in a cell of dimensions a = 7.895(2 Å, b = 11.196(3 Å, and c = 12. 544(2 Å, and b = 98.39(2o. The structure has been refined to a final value of the conventional R-factor of 0.0312 based on 1568 observed independent reflections. There is a crystallographic inversion center in the middle of the dimer relating one manganese center to the other. The geometry at each manganese(II center is again roughly octahedral, coordination being provided by two nitrogen atoms from the oxime ligand, a terminal chloride ion trans to the amine nitrogen, the oxygen atom of the coordinated methanol molecule, and two bridging chlorides that link the two halves of the dimer. The Mn

Supported versus colloidal zinc oxide for advanced oxidation processes

Science.gov (United States)

Laxman, Karthik; Al Rashdi, Manal; Al Sabahi, Jamal; Al Abri, Mohammed; Dutta, Joydeep

2017-07-01

Photocatalysis is a green technology which typically utilizes either supported or colloidal catalysts for the mineralization of aqueous organic contaminants. Catalyst surface area and surface energy are the primary factors determining its efficiency, but correlation between the two is still unclear. This work explores their relation and hierarchy in a photocatalytic process involving both supported and colloidal catalysts. In order to do this the active surface areas of supported zinc oxide nanorods (ZnO NR's) and colloidal zinc oxide nanoparticles (having different surface energies) were equalized and their phenol oxidation mechanism and capacity was analyzed. It was observed that while surface energy had subtle effects on the oxidation rate of the catalysts, the degradation efficiency was primarily a function of the surface area; which makes it a better parameter for comparison when studying different catalyst forms of the same material. Thus we build a case for the use of supported catalysts, wherein their catalytic efficiency was tested to be unaltered over several days under both natural and artificial light, suggesting their viability for practical applications.

The effect of polymers onto the size of zinc layered hydroxide salt and its calcined product

Science.gov (United States)

Hussein, Mohd Zobir bin; Ghotbi, Mohammad Yeganeh; Yahaya, Asmah Hj; Abd Rahman, Mohd Zaki

2009-02-01

Zinc hydroxide nitrate, a brucite-like layered material was synthesized using pH control method. Poly(vinyl alcohol) and poly(ethylene glycol) were used at various percentages as size decreasing agents during the synthesis of zinc hydroxide nitrate. SEM and PXRD showed the decrease of size and thickness of the resultant zinc hydroxide nitrates. TG and surface area data confirmed the decrease of the particle sizes, too. When zinc hydroxide nitrates were heat treated at 500 °C, the physical properties of nano zinc oxides obtained depended on the parent material, zinc hydroxide nitrate.

Synthesis, characterization and thermal studies of nickel (II), copper (II), zinc (II) and cadmium (II) complexes with some mixed ligands

International Nuclear Information System (INIS)

Mitra, Samiran; Kundu, Parimal; Singh, Rajkumar Bhubon

1998-01-01

Dichloro-(DCA) and trichloroacetate(TCA) -cyclic ligand morpholine (Morph)/thiomorpholine (Tmorph)/methylmorpholine (Mmorph)/dimethyl-piperazine (DMP) complexes of nickel (II), copper (II), zinc (II) and cadmium (II) with the compositions [Ni(tmorph) 2 (DCA) 2 ], [Ni(tmorph) 2 (TCA) 2 ].2H 2 O, [Cu(DMP) 2 (TCA) 2 ],[ML 2 X 2 ].nH 2 O where M=Zn II or Cd II , L=Morph, DMP or tmorph and X=DCA or TCA and n=O except in case of [Cd (Morph) 2 (TCA) 2 ] where n=1 have been synthesised. Some intermediate complexes have been isolated by temperature arrest technique (pyrolysis) and characterised. Configurational and conformational changes have been studied by elemental analyses, IR and electronic spectra, magnetic moment data (in the case of Ni(II) and Cu(II) complexes) and thermal analysis. E a * , ΔH, and ΔS for the decomposition reaction of these complexes are evaluated and the stability of the complexes with respect to activation energy has also been compared. The linear correlation has been found between E a * and ΔS for the decomposition of the complexes. (author)

A study on the isotope effects in the reduction of carbon dioxide by zinc

International Nuclear Information System (INIS)

Senegacnik, M.

1957-06-01

We have determined the isotope effects which occur in the reduction of carbon dioxide by zinc. It has been shown that in the case of irreversible surface reactions, Bernstein's equation which permits the calculation of the fractionation factor is still valid. These experimental factors are in good agreement with those obtained by calculating the partition functions of the adsorbed activated complexes. In the reaction mechanism used, the model of the activated complex corresponds to the dissociation of one of the carbon oxygen bonds CO 2 → CO + O. Perturbations arising from the slight reversibility of the reaction Zn + CO 2 ↔ ZnO + CO on the isotope effects on the carbon and oxygen atoms have also been calculated. (author) [fr

Effect of consuming zinc-fortified bread on serum zinc and iron status of zinc-deficient women: A double blind, randomized clinical trial

Directory of Open Access Journals (Sweden)

Akbar Badii

2012-01-01

Full Text Available After iron deficiency, zinc deficiency is the major micronutrient deficiency in developing countries, and staple food fortification is an effective strategy to prevent and improve it among at-risk-populations. No action has been taken to reduce zinc deficiency via flour fortification so far in Iran, and little is known about the influence of zinc fortification of flour on serum zinc and the iron status, and also about the optimum and effective amount of zinc compound that is used in food fortification. The objective of this study is to evaluate the influence of consuming zinc-fortified breads on the zinc and iron status in the blood serum. In this study, three types of bread were prepared from non-fortified and fortified flours, with 50 and 100 ppm elemental zinc in the form of sulfate. Eighty zinc-deficient women aged 19 to 49 years were randomly assigned to three groups; The volunteers received, daily, (1 a non-fortified bread, (2 a high-zinc bread, and (3 a low-zinc bread for one month. Serum zinc and iron were measured by Atomic Absorption before and after the study. Results showed a significant increase in serum zinc and iron levels in all groups (p 0.05. Absorption of zinc and iron in the group that consumed high-zinc bread was significantly greater than that in the group that received low-zinc bread (p < 0.01. It was concluded that fortification of flour with 50-100 ppm zinc was an effective way to achieve adequate zinc intake and absorption in zinc-deficient people. It also appeared that consuming zinc-fortified bread improved iron absorption.

Water resistant surfaces using zinc oxide structured nanorod arrays with switchable wetting property

OpenAIRE

Ennaceri, H.; Wang, L.; Erfurt, D.; Riedel, W.; Mangalgiri, G.; Khaldoun, A.; El Kenz, A.; Benyoussef, A.; Ennaoui, A

2016-01-01

This study presents an experimental approach for fabricating super hydrophobic coatings based on a dual roughness structure composed of zinc oxide nanorod arrays coated with a sputtered zinc oxide nano layer. The ZnO nanorod arrays were grown by means of a low temperature electrochemical deposition technique 75 C on FTO substrates. The ZnO nanorods show a 002 orientation along the c axis, and have a hexagonal structure, with an average length of 710 nm, and average width of 156 nm. On th...

Zinc and lead detoxifying abilities of humic substances relevant to environmental bacterial species.

Science.gov (United States)

Perelomov, L V; Sarkar, Binoy; Sizova, O I; Chilachava, K B; Shvikin, A Y; Perelomova, I V; Atroshchenko, Y M

2018-04-30

The effect of humic substances (HS) and their different fractions (humic acids (HA) and hymatomelanic acids (HMA)) on the toxicity of zinc and lead to different strains of bacteria was studied. All tested bacteria demonstrated a lower resistance to zinc than lead showing minimum inhibitory concentrations of 0.1 - 0.3mM and 0.3-0.5mM, respectively. The highest resistance to lead was characteristic of Pseudomonas chlororaphis PCL1391 and Rhodococcus RS67, while Pseudomonas chlororaphis PCL1391 showed the greatest resistance to zinc. The combined fractions of HS and HA alone reduced zinc toxicity at all added concentrations of the organic substances (50 - 200mgL -1 ) to all microorganisms, while hymatomelanic acids reduced zinc toxicity to Pseudomonas chlororaphis PCL1391 at 200mgL -1 organic concentration only. The HS fractions imparted similar effects on lead toxicity also. This study demonstrated that heavy metal toxicity to bacteria could be reduced through complexation with HS and their fractions. This was particularly true when the metal-organic complexes held a high stability, and low solubility and bioavailability. Copyright © 2018 Elsevier Inc. All rights reserved.

Properties of tire rubber with zinc-containing technological additives

Directory of Open Access Journals (Sweden)

S. N. Kayushnikov

2017-01-01

Full Text Available In this paper, we studied the influence of zinc-containing technological additives on partial replacement of zinc oxide and stearic acid on deformation-strength and performance properties of tire elastomeric compositions based on polyisoprene rubber and combination of oil-filled butadiene-styrene and polybutadiene rubbers. It was revealed that partial replacement of zinc oxide and stearic acid with zinc-containing technological additives does not significantly affect the basic physico-mechanical properties of rubbers based on synthetic rubbers of general use. It was determined that the introduction of zinc-containing technological additives SCC2 in combination with zinc oxide in all the studied ratios and SCC3 in combination with zinc oxide in 4: 1 and 3: 1 ratios leads to increase (up to 10.4% of the resistance of these rubbers under the action of temperature-force fields, which is probably due to a more even distribution of polar components of curing system in non-polar elastomeric matrix, as well as the type of cross-links formed during vulcanization under the action of surface-active additives. It has been found that the introduction of zinc-containing additives into the elastomeric compositions based on SRMS-30 ARKM-15 + SRD in combination with zinc oxide leads to increase to 6.3% of wear resistance of rubbers, which may be due to a lower defectiveness of vulcanization structure of these rubbers, concentration of stress centers in the material. For rubbers based on SRI-3, preservation of bond strength of rubber with a textile cord at a sufficiently high level is shown.

Factors influencing the cytotoxicity of zinc oxide nanoparticles: particle size and surface charge

International Nuclear Information System (INIS)

Baek, M; Kim, M K; Cho, H J; Lee, J A; Yu, J; Chung, H E; Choi, S J

2011-01-01

Zinc oxide (ZnO) nanoparticle is one of the most important materials in diverse applications, since it has UV light absorption, antimicrobial, catalytic, semi-conducting, and magnetic properties. However, there is little information about the toxicological effects of ZnO nanoparticles with respect to physicochemical properties. The aim of this study was, therefore, to evaluate the relationships between cytotoxicity and physicochemical properties of ZnO nanoparticle such as particle size and surface charge in human lung cells. Two different sizes of ZnO nanoparticles (20 and 70 nm) were prepared with positive (+) or negative (-) charge, and then, cytotoxicity of different ZnO nanoparticles was evaluated by measuring cell proliferation in short-term and long-term, membrane integrity, and generation of reactive oxygen species (ROS). The results demonstrated that smaller particles exhibited high cytotoxic effects compared to larger particles in terms of inhibition of cell proliferation, membrane damage, and ROS generation. In addition, positively charged ZnO showed greater ROS production than ZnO with negative charge. These findings suggest that the cytoxicity of ZnO nanoparticles are strongly affected by their particle size and surface charge, highlighting the role of the physicochemical properties of nanoparticles to understand and predict their potential adverse effects on human.

Factors influencing the cytotoxicity of zinc oxide nanoparticles: particle size and surface charge

Energy Technology Data Exchange (ETDEWEB)

Baek, M; Kim, M K; Cho, H J; Lee, J A; Yu, J; Chung, H E; Choi, S J, E-mail: sjchoi@swu.ac.kr [Department of Food Science and Technology, Seoul Women' s University, 126 Gongneung 2-dong, Nowon-gu, Seoul 139-774 (Korea, Republic of)

2011-07-06

Zinc oxide (ZnO) nanoparticle is one of the most important materials in diverse applications, since it has UV light absorption, antimicrobial, catalytic, semi-conducting, and magnetic properties. However, there is little information about the toxicological effects of ZnO nanoparticles with respect to physicochemical properties. The aim of this study was, therefore, to evaluate the relationships between cytotoxicity and physicochemical properties of ZnO nanoparticle such as particle size and surface charge in human lung cells. Two different sizes of ZnO nanoparticles (20 and 70 nm) were prepared with positive (+) or negative (-) charge, and then, cytotoxicity of different ZnO nanoparticles was evaluated by measuring cell proliferation in short-term and long-term, membrane integrity, and generation of reactive oxygen species (ROS). The results demonstrated that smaller particles exhibited high cytotoxic effects compared to larger particles in terms of inhibition of cell proliferation, membrane damage, and ROS generation. In addition, positively charged ZnO showed greater ROS production than ZnO with negative charge. These findings suggest that the cytoxicity of ZnO nanoparticles are strongly affected by their particle size and surface charge, highlighting the role of the physicochemical properties of nanoparticles to understand and predict their potential adverse effects on human.

Production of zinc pellets

Science.gov (United States)

Cooper, J.F.

1996-11-26

Uniform zinc pellets are formed for use in batteries having a stationary or moving slurry zinc particle electrode. The process involves the cathodic deposition of zinc in a finely divided morphology from battery reaction product onto a non-adhering electrode substrate. The mossy zinc is removed from the electrode substrate by the action of gravity, entrainment in a flowing electrolyte, or by mechanical action. The finely divided zinc particles are collected and pressed into pellets by a mechanical device such as an extruder, a roller and chopper, or a punch and die. The pure zinc pellets are returned to the zinc battery in a pumped slurry and have uniform size, density and reactivity. Applications include zinc-air fuel batteries, zinc-ferricyanide storage batteries, and zinc-nickel-oxide secondary batteries. 6 figs.

Surface plasmon resonance-based fiber-optic hydrogen gas sensor utilizing palladium supported zinc oxide multilayers and their nanocomposite.

Science.gov (United States)

Tabassum, Rana; Gupta, Banshi D

2015-02-10

We analyze surface plasmon resonance-based fiber-optic sensor for sensing of small concentrations of hydrogen gas in the visible region of the electromagnetic spectrum. One of the two probes considered has multilayers of zinc oxide (ZnO) and palladium (Pd) while the other has layer of their composite over a silver coated unclad core of the fiber. The analysis is carried out for different volume fractions of palladium nanoparticles dispersed in zinc oxide host material in the nanocomposite layer. For the analysis, a Maxwell-Garnett model is adopted for calculating the dielectric function of a ZnO:Pd nanocomposite having nanoparticles of dimensions smaller than the wavelength of radiation used. The effects of the volume fraction of the nanoparticles in the nanocomposite and the thickness of the nanocomposite layer on the figure of merit of the sensor have been studied. The film thickness of the layer and the volume fraction of nanoparticles in the ZnO:Pd nanocomposite layer have been optimized to achieve the maximum value of the figure of merit of the sensor. It has been found that the figure of merit of the sensing probe coated with ZnO:Pd nanocomposite is more than twofold of the sensing probe coated with multilayers of Pd and ZnO over a silver coated unclad core of the fiber; hence, the sensor with a nanocomposite layer works better than that with multilayers of zinc oxide and palladium. The sensor can be used for online monitoring and remote sensing of hydrogen gas.

Corrosion mechanism of model zinc-magnesium alloys in atmospheric conditions

International Nuclear Information System (INIS)

Prosek, T.; Nazarov, A.; Bexell, U.; Thierry, D.; Serak, J.

2008-01-01

Recently, superior corrosion properties of zinc coatings alloyed with magnesium have been reported. Corrosion behaviour of model zinc-magnesium alloys was studied to understand better the protective mechanism of magnesium in zinc. Alloys containing from 1 to 32 wt.% magnesium, pure zinc, and pure magnesium were contaminated with sodium chloride and exposed to humid air for 28 days. Composition of corrosion products was analyzed using infrared spectroscopy (FTIR), ion chromatography (IC), and Auger electron spectroscopy (AES). The exposure tests were completed with scanning Kelvin probe (SKP) and electrochemical measurements. Weight loss of ZnMg alloys with 1-16 wt.% magnesium was lower than that of pure zinc. Up to 10-fold drop in weight loss was found for materials with 4-8 wt.% Mg in the structure. The improved corrosion stability of ZnMg alloys was connected to the presence of an Mg-based film adjacent to the metal surface. It ensured stable passivity in chloride environment and limited the efficiency of oxygen reduction

Influence of stripping and cooling atmospheres on surface properties and corrosion of zinc galvanizing coatings

International Nuclear Information System (INIS)

Yasakau, K.A.; Giner, I.; Vree, C.; Ozcan, O.; Grothe, R.; Oliveira, A.; Grundmeier, G.; Ferreira, M.G.S.; Zheludkevich, M.L.

2016-01-01

Highlights: • Stripping/cooling atmosphere affects surfaces chemical composition of Zn and Zn-Al-Mg galvanized coatings. • Higher peel forces of model adhesive films were obtained on zinc alloys samples prepared under nitrogen atmosphere. • Localized corrosion attack originates at grain boundaries on Zn galvanized coating. • Visible dissolution of MgZn_2 phase was observed by in situ AFM only at binary eutectics and not at ternary ones. - Abstract: In this work the influence of stripping/cooling atmospheres used after withdrawal of steel sheet from Zn or Zn-alloy melt on surface properties of Zn (Z) and Zn-Al-Mg (ZM) hot-dip galvanizing coatings has been studied. The aim was to understand how the atmosphere (composed by nitrogen (N_2) or air) affects adhesion strength to model adhesive and corrosive behaviour of the galvanized substrates. It was shown that the surface chemical composition and Volta potential of the galvanizing coatings prepared under the air or nitrogen atmosphere are strongly influenced by the atmosphere. The surface chemistry Z and ZM surfaces prepared under N_2 contained a higher content of metal atoms and a richer hydroxide density than the specimens prepared under air atmosphere as assessed by X-ray photoelectron spectroscopy (XPS). The induced differences on the microstructure of the galvanized coatings played a key role on the local corrosion induced defects as observed by means of in situ Atomic force microscopy (AFM). Peel force tests performed on the substrates coated by model adhesive films indicate a higher adhesive strength to the surfaces prepared under nitrogen atmosphere. The obtained results have been discussed in terms of the microstructure and surface chemical composition of the galvanizing coatings.

Cysteine-rich intestinal protein binds zinc during transmucosal zinc transport

International Nuclear Information System (INIS)

Hempe, J.M.; Cousins, R.J.

1991-01-01

The mechanism of zinc absorption has not been delineated, but kinetic studies show that both passive and carrier-mediated processes are involved. The authors have identified a low molecular mass zinc-binding protein in the soluble fraction of rat intestinal mucosa that could function as an intracellular zinc carrier. The protein was not detected in liver or pancreas, suggesting a role specific to the intestine. The protein binds zinc during transmucosal zinc transport and shows signs of saturation at higher luminal zinc concentrations, characteristics consistent with a role in carrier-mediated zinc absorption. Microsequence analysis of the protein purified by gel-filtration HPCL and SDS/PAGE showed complete identity within the first 41 N-terminal amino acids with the deduced protein sequence of cysteine-rich intestinal protein. These investigators showed that the gene for this protein is developmentally regulated in neonates during the suckling period, conserved in many vertebrate species, and predominantly expressed in the small intestine. Cysteine-rich intestinal protein contains a recently identified conserved sequence of histidine and cysteine residues, the LIM motif, which our results suggest confers metal-binding properties that are important for zinc transport and/or functions of this micronutrient

Synthesis, thermal, spectral, and biological properties of zinc(II) 4-aminobenzoate complexes

Czech Academy of Sciences Publication Activity Database

Homzová, K.; Györyová, K.; Hudecová, D.; Koman, M.; Melník, M.; Kovářová, Jana

2017-01-01

Roč. 129, č. 2 (2017), s. 1065-1082 ISSN 1388-6150 Institutional support: RVO:61389013 Keywords : zinc(II) 4-aminobenzoate * thermal * spectral Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.953, year: 2016

Zinc Signals and Immunity.

Science.gov (United States)

Maywald, Martina; Wessels, Inga; Rink, Lothar

2017-10-24

Zinc homeostasis is crucial for an adequate function of the immune system. Zinc deficiency as well as zinc excess result in severe disturbances in immune cell numbers and activities, which can result in increased susceptibility to infections and development of especially inflammatory diseases. This review focuses on the role of zinc in regulating intracellular signaling pathways in innate as well as adaptive immune cells. Main underlying molecular mechanisms and targets affected by altered zinc homeostasis, including kinases, caspases, phosphatases, and phosphodiesterases, will be highlighted in this article. In addition, the interplay of zinc homeostasis and the redox metabolism in affecting intracellular signaling will be emphasized. Key signaling pathways will be described in detail for the different cell types of the immune system. In this, effects of fast zinc flux, taking place within a few seconds to minutes will be distinguish from slower types of zinc signals, also designated as "zinc waves", and late homeostatic zinc signals regarding prolonged changes in intracellular zinc.

The kinetic of photoreactions in zinc oxide microrods

Science.gov (United States)

Fiedot, M.; Rac, O.; Suchorska-Woźniak, P.; Nawrot, W.; Teterycz, H.

2016-01-01

Zinc oxide is the oldest sensing material used in the chemical resistive gas sensors which allow to detect many gases, such as carbon oxide, nitrogen oxides and other. This material is also widely used in medicine and daily life as antibacterial agent. For this reason this semiconductor is often synthesized on the polymer substrates such as foils and textiles. In presented results zinc oxide was deposited on the surface of poly(ethylene terephthalate) foil to obtain antibacterial material. As synthesis method chemical bath deposition was chosen. The growth of zinc oxide structures was carried out in water solution of zinc nitrate (V) and hexamethylenetetramine in 90°C during 9 h. Because antibacterial properties of ZnO are strongly depended on photocatalytic and electric properties of this semiconductor impedance spectroscopy measurements were carried out. During the measurements material was tested with and without UV light to determinate the kinetic of photoreactions in zinc oxide. Moreover the composite was analyzed by XRD diffraction and scanning electron microscope. The X-ray analysis indicated that obtained material has the structure of wurtzite which is typical of zinc oxide. SEM images showed that on the PET foil microrods of ZnO were formed. The impedance spectroscopy measurements of ZnO layer showed that in UV light significant changes in the conductivity of the material are observed.

The kinetic of photoreactions in zinc oxide microrods

International Nuclear Information System (INIS)

Fiedot, M; Rac, O; Suchorska-Woźniak, P; Nawrot, W; Teterycz, H

2016-01-01

Zinc oxide is the oldest sensing material used in the chemical resistive gas sensors which allow to detect many gases, such as carbon oxide, nitrogen oxides and other. This material is also widely used in medicine and daily life as antibacterial agent. For this reason this semiconductor is often synthesized on the polymer substrates such as foils and textiles. In presented results zinc oxide was deposited on the surface of poly(ethylene terephthalate) foil to obtain antibacterial material. As synthesis method chemical bath deposition was chosen. The growth of zinc oxide structures was carried out in water solution of zinc nitrate (V) and hexamethylenetetramine in 90°C during 9 h. Because antibacterial properties of ZnO are strongly depended on photocatalytic and electric properties of this semiconductor impedance spectroscopy measurements were carried out. During the measurements material was tested with and without UV light to determinate the kinetic of photoreactions in zinc oxide. Moreover the composite was analyzed by XRD diffraction and scanning electron microscope. The X-ray analysis indicated that obtained material has the structure of wurtzite which is typical of zinc oxide. SEM images showed that on the PET foil microrods of ZnO were formed. The impedance spectroscopy measurements of ZnO layer showed that in UV light significant changes in the conductivity of the material are observed

Adsorption and photocatalytic properties of transition metal Zinc(II) complex based on 5-(4-(tetrazol-5-yl)phenyl)isophthalic acid

Science.gov (United States)

Qiao, Yu; Ren, Shan-Shan; Liu, Li-Hui; Guan, Wei-Sheng; Li, Zhi-Min; Che, Guang-Bo; Liu, Chun-Bo; Wang, Yan-Yan; Wang, Qing-Wei; Li, Xiu-Ying; Zhu, En-Wei

2018-06-01

A new coordination polymeric zinc(II) complex, namely, [Zn2(L)(H2O)3]n·nNO3(1), (H3L = 5-(4-(tetrazol-5-yl)phenyl)isophthalic acid) has been synthesized under solvothermal conditions and structurally characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction analysis and powder X-ray diffraction. Complex 1 exhibits a three-dimensional structure with a Schläfli symbol of 44•69•82 topologies, constructed from two crystallographically independent five and six coordinated mode with metal center and connected H3L ligands. The complex has good thermal stability and excellent photoluminescent property. Furthermore, by comparing the photoluminescent and photocatalytic mutation results induced by interconversion of metal ions, we confirm that the properties mutation induced by metal ions is much controllable and obvious. In addition, the complex exhibits significantly enhanced photocatalytic activity for methylene blue (MB) under UV light irradiation (λ < 400 nm), and the degradation rate could reach 75% in 80 min. Meanwhile trapping experiments indicated that the •O2- and h+ are the main activated species.

Study of silicon doped with zinc ions and annealed in oxygen

Energy Technology Data Exchange (ETDEWEB)

Privezentsev, V. V., E-mail: v.privezentsev@mail.ru [Russian Academy of Sciences, Institute of Physics and Technology (Russian Federation); Kirilenko, E. P.; Goryachev, A. N. [Zelenograd, National Research University of Electronic Technology “MIET” (Russian Federation); Batrakov, A. A. [National Research University “MEI” (Russian Federation)

2017-02-15

The results of studies of the surface layer of silicon and the formation of precipitates in Czochralski n-Si (100) samples implanted with {sup 64}Zn{sup +} ions with an energy of 50 keV and a dose of 5 × 10{sup 16} cm{sup –2} at room temperature and then oxidized at temperatures from 400 to 900°C are reported. The surface is visualized using an electron microscope, while visualization of the surface layer is conducted via profiling in depth by elemental mapping using Auger electron spectroscopy. The distribution of impurity ions in silicon is analyzed using a time-of-flight secondary-ion mass spectrometer. Using X-ray photoelectron spectroscopy, the chemical state of atoms of the silicon matrix and zinc and oxygen impurity atoms is studied, and the phase composition of the implanted and annealed samples is refined. After the implantation of zinc, two maxima of the zinc concentration, one at the wafer surface and the other at a depth of 70 nm, are observed. In this case, nanoparticles of the Zn metal phase and ZnO phase, about 10 nm in dimensions, are formed at the surface and in the surface layer. After annealing in oxygen, the ZnO · Zn{sub 2}SiO{sub 4} and Zn · ZnO phases are detected near the surface and at a depth of 50 nm, respectively.

Effect of Consuming Zinc-fortified Bread on Serum Zinc and Iron Status of Zinc-deficient Women: A Double Blind, Randomized Clinical Trial.

Science.gov (United States)

Badii, Akbar; Nekouei, Niloufar; Fazilati, Mohammad; Shahedi, Mohammad; Badiei, Sajad

2012-03-01

After iron deficiency, zinc deficiency is the major micronutrient deficiency in developing countries, and staple food fortification is an effective strategy to prevent and improve it among at-risk-populations. No action has been taken to reduce zinc deficiency via flour fortification so far in Iran, and little is known about the influence of zinc fortification of flour on serum zinc and the iron status, and also about the optimum and effective amount of zinc compound that is used in food fortification. The objective of this study is to evaluate the influence of consuming zinc-fortified breads on the zinc and iron status in the blood serum. In this study, three types of bread were prepared from non-fortified and fortified flours, with 50 and 100 ppm elemental zinc in the form of sulfate. Eighty zinc-deficient women aged 19 to 49 years were randomly assigned to three groups; The volunteers received, daily, (1) a non-fortified bread, (2) a high-zinc bread, and (3) a low-zinc bread for one month. Serum zinc and iron were measured by Atomic Absorption before and after the study. Results showed a significant increase in serum zinc and iron levels in all groups (p 0.05). Absorption of zinc and iron in the group that consumed high-zinc bread was significantly greater than that in the group that received low-zinc bread (p bread improved iron absorption.

Further Aspects of Ochratoxin A-Cation Interactions: Complex Formation with Zinc Ions and a Novel Analytical Application of Ochratoxin A-Magnesium Interaction in the HPLC-FLD System

Directory of Open Access Journals (Sweden)

Miklós Poór

2014-04-01

Full Text Available Ochratoxin A (OTA is a mycotoxin produced by different Aspergillus and Penicillium species. Since its mechanism of action is not fully understood yet, it is important to gain further insight into different interactions of OTA at the molecular level. OTA is found worldwide in many foods and drinks. Moreover, it can also be detected in human and animal tissues and body fluids, as well. Therefore, the development of highly sensitive quantitative methods for the determination of OTA is of utmost importance. OTA most likely forms complexes with divalent cations, both in cells and body fluids. In the present study, the OTA-zinc interaction was investigated and compared to OTA-magnesium complex formation using fluorescence spectroscopy and molecular modeling. Our results show that zinc(II ion forms a two-fold higher stable complex with OTA than magnesium(II ion. In addition, based on the enhanced fluorescence emission of OTA in its magnesium-bound form, a novel RP-HPLC-fluorescence detector (FLD method was also established. Our results highlight that the application of magnesium chloride in alkaline eluents results in an approximately two-fold increase in sensitivity using the HPLC-FLD technique.

Leptin and zinc relation : In regulation of food intake and immunity

Directory of Open Access Journals (Sweden)

Abdulkerim Kasim Baltaci

2012-01-01

Full Text Available Leptin is synthesized and released by the adipose tissue. Leptin, which carries the information about energy reserves of the body to the brain, controls food intake by acting on neuropeptide Y (NPY, which exercises a food-intake-increasing effect through relevant receptors in the hypothalamus. Zinc deficiency is claimed to result in anorexia, weight loss, poor food efficiency, and growth impairment. The fact that obese individuals have low zinc and high leptin levels suggests that there is a relation between zinc and nutrition, and consequently also between zinc and leptin. Leptin deficiency increases the predisposition to infections and this increase is associated with the impairments in the production of cytokines. Zinc has a key role in the sustenance of immune resistance against infections. Dietary zinc deficiency negatively affects CD +4 cells, Th functions, and consequently, cell-mediated immunity by causing a decrease in the production of IL-2, IF-γ, and TNF-α, which are Th1 products. The relation between zinc and the concerned cytokines in particular, and the fact that leptin has a part in the immune responses mediated by these cytokines demonstrate that an interaction among cellular immunity, leptin and zinc is inevitable. An overall evaluation of the information presented above suggests that there are complex relations among food intake, leptin and zinc on one hand and among cellular immunity, leptin and zinc on the other. The aim of the present review was to draw attention to the possible relation between zinc and leptin in dietary regulation and cellular immunity.

Zinc

Science.gov (United States)

... Some early research suggests that zinc supplementation increases sperm count, testosterone levels, and pregnancy rates in infertile men with low testosterone levels. Other research suggests that taking zinc can improve sperm shape in men with moderate enlargement of a ...

Relationship between maternal serum zinc, cord blood zinc and ...

African Journals Online (AJOL)

Background: Adequate in utero supply of zinc is essential for optimal fetal growth because of the role of zinc in cellular division, growth and differentiation. Low maternal serum zinc has been reported to be associated with low birth weight and the later is associated with increased morbidity and mortality in newborns.

BWR zinc addition Sourcebook

International Nuclear Information System (INIS)

Garcia, Susan E.; Giannelli, Joseph F.; Jarvis, Alfred J.

2014-01-01

Boiling Water Reactors (BWRs) have been injecting zinc into the primary coolant via the reactor feedwater system for over 25 years for the purpose of controlling primary system radiation fields. The BWR zinc injection process has evolved since the initial application at the Hope Creek Nuclear Station in 1986. Key transitions were from the original natural zinc oxide (NZO) to depleted zinc oxide (DZO), and from active zinc injection of a powdered zinc oxide slurry (pumped systems) to passive injection systems (zinc pellet beds). Zinc addition has continued through various chemistry regimes changes, from normal water chemistry (NWC) to hydrogen water chemistry (HWC) and HWC with noble metals (NobleChem™) for mitigation of intergranular stress corrosion cracking (IGSCC) of reactor internals and primary system piping. While past reports published by the Electric Power Research Institute (EPRI) document specific industry experience related to these topics, the Zinc Sourcebook was prepared to consolidate all of the experience gained over the past 25 years. The Zinc Sourcebook will benefit experienced BWR Chemistry, Operations, Radiation Protection and Engineering personnel as well as new people entering the nuclear power industry. While all North American BWRs implement feedwater zinc injection, a number of other BWRs do not inject zinc. This Sourcebook will also be a valuable resource to plants considering the benefits of zinc addition process implementation, and to gain insights on industry experience related to zinc process control and best practices. This paper presents some of the highlights from the Sourcebook. (author)

Electrodeposition of gallium and zinc onto aluminium. Influence of the electrodeposited metals on the activation process

International Nuclear Information System (INIS)

Flamini, D.O.; Saidman, S.B.; Bessone, J.B.

2007-01-01

The electrodeposition of gallium and/or zinc on aluminium, aluminium-zinc alloy and vitreous carbon electrodes in chloride solutions is analysed. The electrodissolution of the formed interfaces is also described and discussed. For this purpose, potentiodynamic and potentiostatic techniques and open circuit potential measurements were employed and surface characterisation was performed by scanning electron microscopy and energy dispersive X-ray analysis. The presence of zinc, electrodeposited from the solution or as an alloying component, facilitates gallium enrichment at the interface and improves the wetting on the aluminium oxide. These conditions ensure the formation of a surface Ga-Al amalgam. As a result, the dissolution process occurs at potentials which are more active than those observed for aluminium or aluminium-zinc alloy in halide solutions

Electrodeposition of gallium and zinc onto aluminium. Influence of the electrodeposited metals on the activation process

Energy Technology Data Exchange (ETDEWEB)

Flamini, D.O. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina); Saidman, S.B. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)], E-mail: ssaidman@criba.edu.ar; Bessone, J.B. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Departamento de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)

2007-07-31

The electrodeposition of gallium and/or zinc on aluminium, aluminium-zinc alloy and vitreous carbon electrodes in chloride solutions is analysed. The electrodissolution of the formed interfaces is also described and discussed. For this purpose, potentiodynamic and potentiostatic techniques and open circuit potential measurements were employed and surface characterisation was performed by scanning electron microscopy and energy dispersive X-ray analysis. The presence of zinc, electrodeposited from the solution or as an alloying component, facilitates gallium enrichment at the interface and improves the wetting on the aluminium oxide. These conditions ensure the formation of a surface Ga-Al amalgam. As a result, the dissolution process occurs at potentials which are more active than those observed for aluminium or aluminium-zinc alloy in halide solutions.

The peculiarity of the formation of zinc films on a glass substrate

Energy Technology Data Exchange (ETDEWEB)

Tomaev, V. V., E-mail: tvaza@mail.ru [Saint Petersburg State University, 198504, Russia, Saint-Petersburg, Petrodvorets, Universitetskii pr. 26 (Russian Federation); Saint Petersburg Mining University, Russia, 199106, St. Petersburg, V.O., 21-st line, 2 (Russian Federation); Polishchuk, V. A., E-mail: vpvova2010@yandex.ru [St. Petersburg University of Information Technologies, Mechanics, and Optics, 197101, Russia, St. Petersburg, Kronverksky Pr., 49 (Russian Federation); Borisov, E. N., E-mail: enbor@bk.ru [Saint Petersburg State University, 198504, Russia, Saint-Petersburg, Petrodvorets, Universitetskii pr. 26 (Russian Federation)

2016-06-17

Thin Nanocrystalline films of the zinc have been fabricated by thermal spraying on the glass substrate. Morphologies and structure of the films had been investigated by the methods X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). It is found that the surface of the films has a different types of the nanocrystals zinc. Were detected intergrowths of two or more the nanocrystals, hexagonal shape. Using the theory of homogeneous and heterogeneous nucleation of a new phase, had been evaluated the geometrical and thermodynamic parameters nanocrystals zinc.

Photoelectrochemical etching of gallium nitride surface by complexation dissolution mechanism

Energy Technology Data Exchange (ETDEWEB)

Zhang, Miao-Rong [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 215123 Suzhou (China); University of Chinese Academy of Sciences, 100049 Beijing (China); Hou, Fei; Wang, Zu-Gang; Zhang, Shao-Hui [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 215123 Suzhou (China); Changchun University of Science and Technology, 130022 Changchun (China); Pan, Ge-Bo, E-mail: gbpan2008@sinano.ac.cn [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 215123 Suzhou (China)

2017-07-15

Graphical abstract: GaN surface was etched by 0.3 M EDTA-2Na. The proposed complexation dissolution mechanism can be applicable to almost all neutral etchants under the prerequisite of strong light and electric field. - Highlights: • GaN surface was etched by EDTA-2Na. • GaN may be dissolved into EDTA-2Na by forming Ga–EDTA complex. • We propose the complexation dissolution mechanism for the first time. - Abstract: Gallium nitride (GaN) surface was etched by 0.3 M ethylenediamine tetraacetic acid disodium (EDTA-2Na) via photoelectrochemical etching technique. SEM images reveal the etched GaN surface becomes rough and irregular. The pore density is up to 1.9 × 10{sup 9} per square centimeter after simple acid post-treatment. The difference of XPS spectra of Ga 3d, N 1s and O 1s between the non-etched and freshly etched GaN surfaces can be attributed to the formation of Ga–EDTA complex at the etching interface between GaN and EDTA-2Na. The proposed complexation dissolution mechanism can be broadly applicable to almost all neutral etchants under the prerequisite of strong light and electric field. From the point of view of environment, safety and energy, EDTA-2Na has obvious advantages over conventionally corrosive etchants. Moreover, as the further and deeper study of such nearly neutral etchants, GaN etching technology has better application prospect in photoelectric micro-device fabrication.

Gallium diffusion in zinc oxide via the paired dopant-vacancy mechanism

Science.gov (United States)

Sky, T. N.; Johansen, K. M.; Riise, H. N.; Svensson, B. G.; Vines, L.

2018-02-01

Isochronal and isothermal diffusion experiments of gallium (Ga) in zinc oxide (ZnO) have been performed in the temperature range of 900-1050 °C. The samples used consisted of a sputter-deposited and highly Ga-doped ZnO film at the surface of a single-crystal bulk material. We use a novel reaction diffusion (RD) approach to demonstrate that the diffusion behavior of Ga in ZnO is consistent with zinc vacancy (VZn) mediation via the formation and dissociation of GaZnVZn complexes. In the RD modeling, experimental diffusion data are fitted utilizing recent density-functional-theory estimates of the VZn formation energy and the binding energy of GaZnVZn. From the RD modeling, a migration energy of 2.3 eV is deduced for GaZnVZn, and a total/effective activation energy of 3.0 eV is obtained for the Ga diffusion. Furthermore, and for comparison, employing the so-called Fair model, a total/effective activation energy of 2.7 eV is obtained for the Ga diffusion, reasonably close to the total value extracted from the RD-modeling.

Zinc at glutamatergic synapses.

Science.gov (United States)

Paoletti, P; Vergnano, A M; Barbour, B; Casado, M

2009-01-12

It has long been known that the mammalian forebrain contains a subset of glutamatergic neurons that sequester zinc in their synaptic vesicles. This zinc may be released into the synaptic cleft upon neuronal activity. Extracellular zinc has the potential to interact with and modulate many different synaptic targets, including glutamate receptors and transporters. Among these targets, NMDA receptors appear particularly interesting because certain NMDA receptor subtypes (those containing the NR2A subunit) contain allosteric sites exquisitely sensitive to extracellular zinc. The existence of these high-affinity zinc binding sites raises the possibility that zinc may act both in a phasic and tonic mode. Changes in zinc concentration and subcellular zinc distribution have also been described in several pathological conditions linked to glutamatergic transmission dysfunctions. However, despite intense investigation, the functional significance of vesicular zinc remains largely a mystery. In this review, we present the anatomy and the physiology of the glutamatergic zinc-containing synapse. Particular emphasis is put on the molecular and cellular mechanisms underlying the putative roles of zinc as a messenger involved in excitatory synaptic transmission and plasticity. We also highlight the many controversial issues and unanswered questions. Finally, we present and compare two widely used zinc chelators, CaEDTA and tricine, and show why tricine should be preferred to CaEDTA when studying fast transient zinc elevations as may occur during synaptic activity.

Role of surface modification in zinc oxide nanoparticles and its toxicity assessment toward human dermal fibroblast cells

Directory of Open Access Journals (Sweden)

Ramasamy M

2014-08-01

Full Text Available Mohankandhasamy Ramasamy,1 Minakshi Das,1 Seong Soo A An,1 Dong Kee Yi2 1Division of Bionanotechnology, Gachon University, Seongnam, 2Department of Chemistry, Myongji University, Yongin, South Korea Abstract: The wide-scale applications of zinc oxide (ZnO nanoparticles (NPs in ­photocatalysts, gas sensors, and cosmetics may cause toxicity to humans and environments. Therefore, the aim of the present study was to reduce the toxicity of ZnO NPs by coating them with a silica (SiO2 layer, which could be used in human applications, such as cosmetic preparations. The sol–gel method was used to synthesize core ZnO with SiO2-shelled NPs (SiO2/ZnO NPs with varying degrees of coating. Diverse studies were performed to analyze the toxicity of NPs against cells in a dose- and time-dependent manner. To ensure the decreased toxicity of the produced SiO2/ZnO NPs, cytotoxicity in membrane damage and/or intracellular reactive oxygen species (ROS were assessed by employing 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide, lactate dehydrogenase, 2',7'-dichlorofluorescin, and lipid peroxide estimations. The cores of ZnO NPs exhibited cytotoxicity over time, regardless of shell thickness. Nevertheless, the thicker SiO2/ZnO NPs revealed reduced enzyme leakage, decreased peroxide production, and less oxidative stress than their bare ZnO NPs or thinner SiO2/ZnO NPs. Therefore, thicker SiO2/ZnO NPs moderated the toxicity of ZnO NPs by restricting free radical formation and the release of zinc ions, and decreasing surface contact with cells. Keywords: zinc oxide, silica coating, photostability, human dermal fibroblast, membrane damage, oxidative stress

A bio-inspired zinc finger analogue anchored in 2D hexagonal meso-porous silica for room temperature CO_2 activation via a hydrogeno-carbonate route

International Nuclear Information System (INIS)

Doghri, Hanene; Baranova, Elena A.; Albela, Belen; Bonneviot, Laurent; Mongia Said-Zina

2017-01-01

Bio-inspired diethylenetriamine-zinc(II) complexes were anchored into the nano-pores of hexagonal meso-porous MCM41-like silicas targeting a carbamate free and low temperature CO_2 recycling process. A step-by-step approach was adopted to perform an in situ synthesis in order to mimic the zinc finger of carbonic anhydrases, the fastest family of enzymes. In the presence of a surface-masking pattern of TMA"+ ions, some silanol groups were capped using grafted trimethylsilyl functions, TMSgr, (gr for grafted). After removing the masking ions, a tridentate diethylenetriamine ligand was anchored using diethylenetriamine propyl-trimethoxysilane. The so-called DETA_a_n ligands (an for anchored) were partially mono-protonated using either cyclohexane or isopropanol as a solvent. Nonetheless, up to two thirds of them were metallated by Zn(II) ions, leading to the targeted anchored zinc finger mimic [Zn(DETAan)L]+(L = Cl or OH). CO_2 is then adsorbed at room temperature and in humid ambient air by the formation of an intermediate hydrogeno-carbonate-zinc complex. Specific IR signatures at 1330 and 1400 cm"-"1 together with characteristic C 1s and Zn 2p3/2 XPS binding energies at 286.4 and 1024.6 eV advocate for a rather symmetrical bidentate [η"2-CO_3] structural unit in the anchored complex [Zn(DETA_a_n)(η"2-HCO_3"*)]"+, where the Zn(II) ion is most likely penta-coordinated. The internal pH value varied by less than 0.5 depending on the metal reacting with the DETA_a_n ligand and its ability to generate HCO_3"-, due to the buffering effect of surface silanol and amino groups according to the level of protonation of the DETA moieties measured from the N 1s XPS spectra. In contrast to nitrate ions, chloride ions were found to inhibit the formation of hydrogeno-carbonate. (authors)

Tracing of Zinc Nanocrystals in the Anterior Pituitary of Zinc-Deficient Wistar Rats.

Science.gov (United States)

Kuldeep, Anjana; Nair, Neena; Bedwal, Ranveer Singh

2017-06-01

The aim of this study was to trace zinc nanocrystals in the anterior pituitary of zinc-deficient Wistar rats by using autometallographic technique. Male Wistar rats (30-40 days of age, pre-pubertal period) of 40-50 g body weight were divided into the following: the ZC (zinc control) group-fed with 100 ppm zinc in diet, the ZD (zinc-deficient) group-fed with zinc-deficient (1.00 ppm) diet and the PF (pair-fed) group-received 100 ppm zinc in diet. The experiments were set for 2 and 4 weeks. Pituitary was removed and processed for the autometallographic technique. The control and pair-fed groups retained their normal morphological features. However, male Wistar rats fed on zinc-deficient diet for 2 and 4 weeks displayed a wide range of symptoms such as significant (P zinc nanocrystals in the nuclei. The present findings suggest that the dietary zinc deficiency causes decreased intensity of zinc nanocrystals localization and their distribution in the pituitary thereby contributing to the dysfunction of the pituitary of the male Wistar rats. The severity of zinc deficiency symptoms progressed after the second week of the experiment. Decreased intensity of zinc nanocrystals attenuates the pituitary function which would exert its affect on other endocrine organs impairing their functions indicating that the metabolic regulation of pituitary is mediated to a certain extent by zinc and/or hypothalamus-hypophysial system which also reflects its essentiality during the period of growth.

The effect of zinc injection into PWR primary coolant on the reduction of radiation buildup and corrosion control. The solubilities of zinc, nickel and cobalt spinel oxides

International Nuclear Information System (INIS)

Miyajima, Kaori; Hirano, Hideo

1999-01-01

The use of zinc injection into PWR primary coolant to reduce radiation buildup has been widely studied, and te reduction effect has been experimentally confirmed. However, some items, such as the optimal concentration of zinc required to reduce radiation buildup, the corrosion control effect of zinc injection, and the influence of zinc injection on the integrity of fuel cladding, have not been clarified yet. In particular, the corrosion suppression effect of zinc remains unconfirmed. Therefore, it is necessary to measure and calculate the solubilities of zinc and nickel spinel oxides, which are formed on the surface of Ni-based alloys in PWR primary systems. In this study, in order to assess the effectiveness of zinc injection in the reduction of radiation buildup and the corrosion control of Ni-based alloy, the potential-pH diagrams for Zn-Cr-H 2 O, Ni-Cr-H 2 O, and Co-Cr-H 2 O systems at 300degC were constructed and the solubilities of Zn-Cr, Ni-Cr, and Co-Cr spinel oxides were calculated. It is concluded that under pH conditions for which NiCr 2 O 4 is stable, zinc injection is effective in corrosion control as well as in reducing radiation buildup. (author)

Surface characterization of the cement for retention of implant supported dental prostheses: In vitro evaluation of cement roughness and surface free energy

Energy Technology Data Exchange (ETDEWEB)

Brajkovic, Denis [Clinic for Dentistry, Department of Maxillofacial Surgery, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, 34000 Kragujevac (Serbia); Antonijevic, Djordje; Milovanovic, Petar [Laboratory for Anthropology, Institute of Anatomy, School of Medicine, University of Belgrade, Dr. Subotica 4/2, 11000 Belgrade (Serbia); Kisic, Danilo [Laboratory for Atomic Physics, Institute of Nuclear Sciences “Vinca”, University of Belgrade, Belgrade (Serbia); Zelic, Ksenija; Djuric, Marija [Laboratory for Anthropology, Institute of Anatomy, School of Medicine, University of Belgrade, Dr. Subotica 4/2, 11000 Belgrade (Serbia); Rakocevic, Zlatko, E-mail: zlatkora@vinca.rs [Laboratory for Atomic Physics, Institute of Nuclear Sciences “Vinca”, University of Belgrade, Belgrade (Serbia)

2014-08-30

Graphical abstract: - Highlights: • Surface free energy and surface roughness influence bacterial adhesion. • Bacterial colonization causes periimplantitis and implant loss. • Zinc-based, glass-ionomers and resin-cements were investigated. • Glass-ionomers-cements present the lowest values of surface free energy and roughness. • Glass-ionomer-cements surface properties result with reduced bacterial adhesion. - Abstract: Background: Material surface free energy and surface roughness strongly influence the bacterial adhesion in oral cavity. The aim of this study was to analyze these two parameters in various commercial luting agents used for cementation of implant restorations. Materials and methods: Zinc-based, glass-ionomers, resin modified glass-ionomer and resin-cements were investigated. Contact angle and surface free energy were measured by contact angle analyzer using Image J software program. Materials’ average roughness and fractal dimension were calculated based on Atomic Force Microscope topography images. Results: Zinc phosphate cements presented significantly higher total surface free energy and significantly lower dispersive component of surface free energy compared to other groups, while resin-cements showed significantly lower polar component than other groups. The surface roughness and fractal dimension values were statistically the highest in the zinc phosphate cements and the lowest for the glass-ionomers cements. Conclusion: Glass-ionomers-cements presented lower values of surface free energy and surface roughness than zinc phosphate and resin cements, indicating that their surfaces are less prone to biofilm adhesion. Practical implications: Within limitations of an in vitro trial, our results indicate that glass-ionomers-cements could be the cements of choice for fixation of cement retained implant restorations due to superior surface properties compared to zinc phosphate and resin cements, which may result in reduced plaque formation

Surface characterization of the cement for retention of implant supported dental prostheses: In vitro evaluation of cement roughness and surface free energy

International Nuclear Information System (INIS)

Brajkovic, Denis; Antonijevic, Djordje; Milovanovic, Petar; Kisic, Danilo; Zelic, Ksenija; Djuric, Marija; Rakocevic, Zlatko

2014-01-01

Graphical abstract: - Highlights: • Surface free energy and surface roughness influence bacterial adhesion. • Bacterial colonization causes periimplantitis and implant loss. • Zinc-based, glass-ionomers and resin-cements were investigated. • Glass-ionomers-cements present the lowest values of surface free energy and roughness. • Glass-ionomer-cements surface properties result with reduced bacterial adhesion. - Abstract: Background: Material surface free energy and surface roughness strongly influence the bacterial adhesion in oral cavity. The aim of this study was to analyze these two parameters in various commercial luting agents used for cementation of implant restorations. Materials and methods: Zinc-based, glass-ionomers, resin modified glass-ionomer and resin-cements were investigated. Contact angle and surface free energy were measured by contact angle analyzer using Image J software program. Materials’ average roughness and fractal dimension were calculated based on Atomic Force Microscope topography images. Results: Zinc phosphate cements presented significantly higher total surface free energy and significantly lower dispersive component of surface free energy compared to other groups, while resin-cements showed significantly lower polar component than other groups. The surface roughness and fractal dimension values were statistically the highest in the zinc phosphate cements and the lowest for the glass-ionomers cements. Conclusion: Glass-ionomers-cements presented lower values of surface free energy and surface roughness than zinc phosphate and resin cements, indicating that their surfaces are less prone to biofilm adhesion. Practical implications: Within limitations of an in vitro trial, our results indicate that glass-ionomers-cements could be the cements of choice for fixation of cement retained implant restorations due to superior surface properties compared to zinc phosphate and resin cements, which may result in reduced plaque formation

Enhanced phosphorescence and electroluminescence in triplet emitters by doping gold into cadmium selenide/zinc sulfide nanoparticles

International Nuclear Information System (INIS)

Liu, H.-W.; Laskar, Inamur R.; Huang, C.-P.; Cheng, J.-A.; Cheng, S.-S.; Luo, L.-Y.; Wang, H.-R.; Chen, T.-M.

2005-01-01

Gold-cadmium selenide/zinc sulfide (Au-CdSe/ZnS) nanocomposites (NCs) were synthesized and characterized by transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, ultraviolet-visible (UV-visible) absorption and photoluminescence (PL) emission spectroscopy. The PL intensity in the Au-CdSe/ZnS NCs system was found to be much greater than that of CdSe/ZnS nanoparticles (NPs) alone, because of the surface-enhanced Raman scattering of Au NPs. Adding Au-CdSe/ZnS NCs to the cyclometalated iridium(III) complex (Ir-complex) greatly enhanced the PL intensity of a triplet emitter. Three double-layered electroluminescence (EL) devices were fabricated where the emitting zone contains the definite mixture of Ir-complex and the NCs [molar concentration of Ir-complex/NCs = 1:0 (Blank, D-1), 1:1 (D-2) and 1:3 (D-3)] and the device D-2 exhibited optimal EL performances

Espectrofotometria de zinco em fertilizantes em fluxo Flow injection spectrophotometry of zinc in mineral fertilizers

Directory of Open Access Journals (Sweden)

Arnaldo Antonio Rodella

1999-07-01

Full Text Available Um sistema de análise química por injeção em fluxo é proposto para a determinação espectrofotométrica de zinco em amostras de misturas de fertilizantes minerais, empregando-se zincon como reagente cromogênico. O procedimento analítico envolve redução de íons metálicos por ácido ascórbico, complexação com íon cianeto, seguindo-se a descomplexação seletiva do zinco com formaldeído, liberando-o para que reaja com o zincon formando um complexo azul. A aplicação do método proposto à extratos de mistura de fertilizantes indicou que a ação de interferentes pode ser contornada e que resultados comparáveis aos da espectrometria de absorção atômica são obtidos.A flow injection system for zinc analysis in mineral fertilizer mixtures is proposed using zincon as chromogenic reagent. The effect of interfering ions such as Cu2+, Fe3+, Mn2+ was eliminated by reduction (using ascorbic acid and complexation of these metal íons with cyanide, with zinc included. Zinc is allowed to react with zincon only after the destruction of the zinc cyano complex with formaldehyde. Flow injection analysis permitted efficient control of the reaction time so that only the zinc ion is set free to produce a blue complex with zincon. Zinc was determined in 16 fertilizer mixtures (3 replicates with precision and accuracy comparable to atomic absorption spectrometry.

Influence of stripping and cooling atmospheres on surface properties and corrosion of zinc galvanizing coatings

Energy Technology Data Exchange (ETDEWEB)

Yasakau, K.A., E-mail: kyasakau@ua.pt [Department of Materials and Ceramic Engineering, CICECO—Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro (Portugal); Giner, I. [Universität Paderborn, Fakultät NW—Department Chemie, Technische und Makromolekulare Chemie, Warburger Strasse 100, D-33098 Paderborn (Germany); Vree, C. [Salzgitter Mannesmann Forschung, GmbH Division Surface Technology, Eisenhüttenstrasse 99, 38239 Salzgitter (Germany); Ozcan, O.; Grothe, R. [Universität Paderborn, Fakultät NW—Department Chemie, Technische und Makromolekulare Chemie, Warburger Strasse 100, D-33098 Paderborn (Germany); Oliveira, A. [Department of Materials and Ceramic Engineering, CICECO—Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro (Portugal); Grundmeier, G. [Universität Paderborn, Fakultät NW—Department Chemie, Technische und Makromolekulare Chemie, Warburger Strasse 100, D-33098 Paderborn (Germany); Ferreira, M.G.S. [Department of Materials and Ceramic Engineering, CICECO—Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro (Portugal); Zheludkevich, M.L. [Department of Materials and Ceramic Engineering, CICECO—Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro (Portugal); Department of Corrosion and Surface Technology, Institute of Materials Research Helmholtz-Zentrum Geesthacht, Max-Planck Str. 1, 21502 Geesthacht (Germany)

2016-12-15

Highlights: • Stripping/cooling atmosphere affects surfaces chemical composition of Zn and Zn-Al-Mg galvanized coatings. • Higher peel forces of model adhesive films were obtained on zinc alloys samples prepared under nitrogen atmosphere. • Localized corrosion attack originates at grain boundaries on Zn galvanized coating. • Visible dissolution of MgZn{sub 2} phase was observed by in situ AFM only at binary eutectics and not at ternary ones. - Abstract: In this work the influence of stripping/cooling atmospheres used after withdrawal of steel sheet from Zn or Zn-alloy melt on surface properties of Zn (Z) and Zn-Al-Mg (ZM) hot-dip galvanizing coatings has been studied. The aim was to understand how the atmosphere (composed by nitrogen (N{sub 2}) or air) affects adhesion strength to model adhesive and corrosive behaviour of the galvanized substrates. It was shown that the surface chemical composition and Volta potential of the galvanizing coatings prepared under the air or nitrogen atmosphere are strongly influenced by the atmosphere. The surface chemistry Z and ZM surfaces prepared under N{sub 2} contained a higher content of metal atoms and a richer hydroxide density than the specimens prepared under air atmosphere as assessed by X-ray photoelectron spectroscopy (XPS). The induced differences on the microstructure of the galvanized coatings played a key role on the local corrosion induced defects as observed by means of in situ Atomic force microscopy (AFM). Peel force tests performed on the substrates coated by model adhesive films indicate a higher adhesive strength to the surfaces prepared under nitrogen atmosphere. The obtained results have been discussed in terms of the microstructure and surface chemical composition of the galvanizing coatings.

Sulfur dioxide leaching of spent zinc-carbon-battery scrap

Energy Technology Data Exchange (ETDEWEB)

Avraamides, J.; Senanayake, G.; Clegg, R. [A.J. Parker Cooperative Research Centre for Hydrometallurgy, Murdoch University, Perth, WA 6150 (Australia)

2006-09-22

Zinc-carbon batteries, which contain around 20% zinc, 35% manganese oxides and 10% steel, are currently disposed after use as land fill or reprocessed to recover metals or oxides. Crushed material is subjected to magnetic separation followed by hydrometallurgical treatment of the non-magnetic material to recover zinc metal and manganese oxides. The leaching with 2M sulfuric acid in the presence of hydrogen peroxide recovers 93% Zn and 82% Mn at 25{sup o}C. Alkaline leaching with 6M NaOH recovers 80% zinc. The present study shows that over 90% zinc and manganese can be leached in 20-30min at 30{sup o}C using 0.1-1.0M sulfuric acid in the presence of sulfur dioxide. The iron extraction is sensitive to both acid concentration and sulfur dioxide flow rate. The effect of reagent concentration and particle size on the extraction of zinc, manganese and iron are reported. It is shown that the iron and manganese leaching follow a shrinking core kinetic model due to the formation of insoluble metal salts/oxides on the solid surface. This is supported by (i) the decrease in iron and manganese extraction from synthetic Fe(III)-Mn(IV)-Zn(II) oxide mixtures with increase in acid concentration from 1M to 2M, and (ii) the low iron dissolution and re-precipitation of dissolved manganese and zinc during prolonged leaching of battery scrap with low sulfur dioxide. (author)

Influence of extracellular zinc on M1 microglial activation.

Science.gov (United States)

Higashi, Youichirou; Aratake, Takaaki; Shimizu, Shogo; Shimizu, Takahiro; Nakamura, Kumiko; Tsuda, Masayuki; Yawata, Toshio; Ueba, Tetuya; Saito, Motoaki

2017-02-27

Extracellular zinc, which is released from hippocampal neurons in response to brain ischaemia, triggers morphological changes in microglia. Under ischaemic conditions, microglia exhibit two opposite activation states (M1 and M2 activation), which may be further regulated by the microenvironment. We examined the role of extracellular zinc on M1 activation of microglia. Pre-treatment of microglia with 30-60 μM ZnCl 2 resulted in dose-dependent increases in interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and tumour necrosis factor-alpha (TNFα) secretion when M1 activation was induced by lipopolysaccharide administration. In contrast, the cell-permeable zinc chelator TPEN, the radical scavenger Trolox, and the P2X7 receptor antagonist A438079 suppressed the effects of zinc pre-treatment on microglia. Furthermore, endogenous zinc release was induced by cerebral ischaemia-reperfusion, resulting in increased expression of IL-1β, IL-6, TNFα, and the microglial M1 surface marker CD16/32, without hippocampal neuronal cell loss, in addition to impairments in object recognition memory. However, these effects were suppressed by the zinc chelator CaEDTA. These findings suggest that extracellular zinc may prime microglia to enhance production of pro-inflammatory cytokines via P2X7 receptor activation followed by reactive oxygen species generation in response to stimuli that trigger M1 activation, and that these inflammatory processes may result in deficits in object recognition memory.

Studies on nitrile rubber degradation in zinc bromide completion fluid and its prevention by surface fluorination

Science.gov (United States)

Vega-Cantu, Yadira Itzel

Poly(acrylonitrile-co-butadiene) or nitrile-butadiene rubber (NBR) is frequently used as an O-ring material in the oil extraction industry due to its excellent chemical properties and resistance to oil. However, degradation of NBR gaskets is known to occur during the well completion and oil extraction process where packers are exposed to completion fluids such as ZnBr2 brine. Under these conditions NBR exhibits accelerated chemical degradation resulting in embrittlement and cracking. Samples of NBR, poly(acrylonitrile) (PAN) and poly(butadiene) (PB) have been exposed to ZnBr2 based completion fluid, and analyzed by ATR and diffuse reflectance IR. Analysis shows the ZnBr2 based completion fluid promotes hydrolysis of the nitrile group to form amides and carboxylic groups. Analysis also shows that carbon-carbon double bonds in NBR are unaffected after short exposure to zinc bromide based completion fluid, but are quickly hydrolyzed in acidic bromide mixtures. Although fluoropolymers have excellent chemical resistance, their strength is less than nitrile rubber and replacing the usual gasket materials with fluoroelastomers is expensive. However, a fluoropolymer surface on a nitrile elastomer can provide the needed chemical resistance while retaining their strength. In this study, we have shown that this can be achieved by direct fluorination, a rather easy and inexpensive process. Samples of NBR O-rings have been fluorinated by exposure to F2 and F2/HF mixtures at various temperatures. Fluorination with F 2 produces the desired fluoropolymer layer; however, fluorination by F2/HF mixtures gave a smoother fluorinated layer at lower temperatures and shorter times. Fluorinated samples were exposed to ZnBr2 drilling fluid and solvents. Elemental analysis shows that the fluorinated layer eliminates ZnBr2 diffusion into the NBR polymeric matrix. It was also found that surface fluorination significantly retards the loss of mechanical properties such as elasticity, tensile

Long-term surveillance of zinc implant in murine artery: Surprisingly steady biocorrosion rate.

Science.gov (United States)

Drelich, Adam J; Zhao, Shan; Guillory, Roger J; Drelich, Jaroslaw W; Goldman, Jeremy

2017-08-01

Metallic zinc implanted into the abdominal aorta of rats out to 6months has been demonstrated to degrade while avoiding responses commonly associated with the restenosis of vascular implants. However, major questions remain regarding whether a zinc implant would ultimately passivate through the production of stable corrosion products or via a cell mediated fibrous encapsulation process that prevents the diffusion of critical reactants and products at the metal surface. Here, we have conducted clinically relevant long term in vivo studies in order to characterize late stage zinc implant biocorrosion behavior and products to address these critical questions. We found that zinc wires implanted in the murine artery exhibit steady corrosion without local toxicity for up to at least 20months post-implantation, despite a steady buildup of passivating corrosion products and intense fibrous encapsulation of the wire. Although fibrous encapsulation was not able to prevent continued implant corrosion, it may be related to the reduced chronic inflammation observed between 10 and 20months post-implantation. X-ray elemental and infrared spectroscopy analyses confirmed zinc oxide, zinc carbonate, and zinc phosphate as the main components of corrosion products surrounding the Zn implant. These products coincide with stable phases concluded from Pourbaix diagrams of a physiological solution and in vitro electrochemical impedance tests. The results support earlier predictions that zinc stents could become successfully bio-integrated into the arterial environment and safely degrade within a time frame of approximately 1-2years. Previous studies have shown zinc to be a promising candidate material for bioresorbable endovascular stenting applications. An outstanding question, however, is whether a zinc implant would ultimately passivate through the production of stable corrosion products or via a cell mediated tissue encapsulation process that prevented the diffusion of critical

Adsorption of Cashew Allergens to Acid-Etched Zinc Metal Particles

Science.gov (United States)

Galvanized metal surfaces are approved by the FDA for use in many food processing steps. Food allergens can cause severe reactions even in very small amounts, and surfaces contaminated with allergens could pose a serious threat. The binding of cashew allergens to zinc particles was evaluated. Whi...

Binding of zinc and iron to wheat bread, wheat bran, and their components.

Science.gov (United States)

Ismail-Beigi, F; Faraji, B; Reinhold, J G

1977-10-01

Wholemeal wheat bread decreases the availability and intestinal absorption of divalent metals. To define this action further, binding of zinc in vitro to a wheat wholemeal bread (Tanok), dephytinized Tanok, and cellulose was determined at pH 5.0 to 7.5. Zinc binding by each was highly pH-dependent and reached a maximum at pH 6.5 to 7.5. Removal of phytate from Tanok did not reduce its binding capability. Wheat bran at pH 6.5 and 6.8 bound 72% of iron (0.5 microgram/ml of solution) and 82.5% of zinc (1.43 microgram/ml solution), respectively. Lignin and two of the hemicellulose fractions of wheat bran and high binding capabilities for zinc (85.6, 87.1, and 82.1%, respectively) whereas a third had a lower zinc-binding capability (38.7%). Binding of zinc to various celluloses and dextrans is also demonstrated. Formation of complexes of these metals with wheat fiber can explain, at least in part, the decreased availability of dietary iron and zinc in wholemeal wheat bread.

PREPARATION OF ZINC ENRICHED YEAST (SACCHAROMYCES CEREVISIAE BY CULTIVATION WITH DIFFERENT ZINC SALTS

Directory of Open Access Journals (Sweden)

Ľuboš Harangozo

2012-02-01

Full Text Available The yeast Saccharomyces cerevisiae is the best known microorganism and therefore widely used in many branches of industry. This study aims to investigate the accumulation of three inorganic zinc salts. Our research presents the ability of this yeast to absorb zinc from liquid medium and such enriched biomass use as a potential source of microelements in animal and/or human nutrition. It was found that the addition of different zinc forms, i.e. zinc nitrate, zinc sulphate and zinc chloride in fixed concentrations of 0, 25, 50 and 100 mg.100 ml-1 did not affect the amount of dry yeast biomass yielded, i.e. 1.0 – 1.2 g of yeast cells from 100 ml of cultivation medium, while higher presence of zinc solutions caused significantly lower yield of yeast biomass. The highest amount of zinc in yeast cells was achieved when added in the form of zinc nitrate in concentration of 200 mg.100 ml-1 YPD medium. The increment of intracellular zinc was up to 18.5 mg.g-1 of yeast biomass.

Self-assembled bilayers based on organothiol and organotrimethoxysilane on zinc platform

International Nuclear Information System (INIS)

Berger, Francois; Delhalle, Joseph; Mekhalif, Zineb

2010-01-01

This study describes the formation of a bilayer system developed on electrodeposited zinc. In a first step, a monolayer of 11-mercapto-1-undecanol is grafted on zinc, optimization of the conditions of elaboration have been performed. In a second step, organotrimethoxysilane have been grafted on the zinc modified with the hydroxyl terminated self-assembled monolayer (SAM) to finalize the bilayer system. X-ray photoelectron spectroscopy (XPS), polarization modulation-infrared reflection absorption spectroscopy (PM-IRRAS) and contact angle measurements are used to characterize each step of modification. An electrochemical evaluation of the different created systems is carried out by linear sweep voltammetry (LSV), cyclic voltammetry (CV) and scanning vibrating electrode technique (SVET). The impact of the modification of zinc using SAM and self-assembled bilayer (SAB) on the electrochemical activity of the surface is highlighted.

The study and microstructure analysis of zinc and zinc oxide

Czech Academy of Sciences Publication Activity Database

Luptáková, Natália; Pešlová, F.; Kliber, J.

2015-01-01

Roč. 54, č. 1 (2015), s. 43-46 ISSN 0543-5846 Grant - others:KEGA(SK) KEGA 007 TnUAD-4/2013 Institutional support: RVO:68081723 Keywords : zinc * production of zinc oxide * microstructure * chemical composition * zinc slag Subject RIV: JG - Metal lurgy Impact factor: 0.959, year: 2014

Zinc Biochemistry: From a Single Zinc Enzyme to a Key Element of Life12

Science.gov (United States)

Maret, Wolfgang

2013-01-01

The nutritional essentiality of zinc for the growth of living organisms had been recognized long before zinc biochemistry began with the discovery of zinc in carbonic anhydrase in 1939. Painstaking analytical work then demonstrated the presence of zinc as a catalytic and structural cofactor in a few hundred enzymes. In the 1980s, the field again gained momentum with the new principle of “zinc finger” proteins, in which zinc has structural functions in domains that interact with other biomolecules. Advances in structural biology and a rapid increase in the availability of gene/protein databases now made it possible to predict zinc-binding sites from metal-binding motifs detected in sequences. This procedure resulted in the definition of zinc proteomes and the remarkable estimate that the human genome encodes ∼3000 zinc proteins. More recent developments focus on the regulatory functions of zinc(II) ions in intra- and intercellular information transfer and have tantalizing implications for yet additional functions of zinc in signal transduction and cellular control. At least three dozen proteins homeostatically control the vesicular storage and subcellular distribution of zinc and the concentrations of zinc(II) ions. Novel principles emerge from quantitative investigations on how strongly zinc interacts with proteins and how it is buffered to control the remarkably low cellular and subcellular concentrations of free zinc(II) ions. It is fair to conclude that the impact of zinc for health and disease will be at least as far-reaching as that of iron. PMID:23319127

An experimental study of the retention of zinc, zinc-cadmium mixture and zinc-65 in the presence of cadmium in Anguilla anguilla (L.)

International Nuclear Information System (INIS)

Pally, Monique; Foulquier, Luc

1976-07-01

Zinc uptake was studied in eels in fresh water, using stable zinc, a zinc-cadmium mixture, and zinc 65 in the presence of small amounts of cadmium. The zinc content in the eel began to increase after 45 days only, and reached approximately 85 ppm after 76 days in water initially containing 5ppm of zinc. At the conclusion of the experiment (76 days), the body organs could be classified in decreasing order in zinc content (in ppm): kidneys (152), skeleton (133), skin (129), muscles (89), head (80), gills (78), digestive tract (77), liver (63) spleen-heart-air bladder (32), and mucus (15). A comparison of experimental results obtained with the zinc-cadmium mixture and cadmium alone showed that zinc decreased the cadmium content of all organs except the gills. The presence of cadmium in water did not inhibit zinc uptake. As cadmium content in water increased, then zinc content in the digestive tract and the kidneys decreased and in all cases remained lower than when zinc alone was present. In the presence of cadmium the percentage of zinc in the kidneys was always lower than the value obtained for zinc alone, and that of the digestive tract did not increase. Contamination of eels treated with 18 and 50ppb of cadmium for 29 days, then contaminated by zinc-65 (5μCi/l) while maintaining the same low cadmium content, showed no significant difference in zinc 65 uptake in the two groups. The same applied to the body organs, and particularly the digestive tract and kidneys, where the highest activity levels were observed. By weight, muscles represented approximately 30% of the total contamination after 45 days [fr

Effect of zinc sources on yield and utilization of zinc in rice-wheat sequence

International Nuclear Information System (INIS)

Deb, D.L.

1990-01-01

A field experiment was conducted on an inceptisol of Delhi to evaluate three sources of zinc, namely, zinc sulphate, zincated urea and zinc oxide on yield and utilization of zinc in rice-wheat sequence. Results indicated that, amongst the three zinc sources, zinc sulphate and zincated urea gave the best performance in increasing the grain yield of rice whereas zinc oxide depressed the grain yield of wheat significantly when compared to other treatments. The highest Zn derived from fertilizer and its utilization was obtained with zinc sulphate for both rice and wheat crops. (author). 9 refs., 4 tabs

Visible-light-enhanced interactions of hydrogen sulfide with composites of zinc (oxy)hydroxide with graphite oxide and graphene.

Science.gov (United States)

Seredych, Mykola; Mabayoje, Oluwaniyi; Bandosz, Teresa J

2012-01-17

Composites of zinc(oxy)hydroxide-graphite oxide and of zinc(oxy)hydroxide-graphene were used as adsorbents of hydrogen sulfide under ambient conditions. The initial and exhausted samples were characterized by XRD, FTIR, potentiometric titration, EDX, thermal analysis, and nitrogen adsorption. An increase in the amount of H(2)S adsorbed/oxidized on their surfaces in comparison with that of pure Zn(OH)(2) is linked to the structure of the composite, the relative number of terminal hydroxyls, and the kind of graphene-based phase used. Although terminal groups are activated by a photochemical process, the graphite oxide component owing to the chemical bonds with the zinc(oxy)hydroxide phase and conductive properties helps in electron transfer, leading to more efficient oxygen activation via the formation of superoxide ions. Elemental sulfur, zinc sulfide, sulfite, and sulfate are formed on the surface. The formation of sulfur compounds on the surface of zinc(oxy)hydroxide during the course of the breakthrough experiments and thus Zn(OH)(2)-ZnS heterojunctions can also contribute to the increased surface activity of our materials. The results show the superiority of graphite oxide in the formation of composites owing to its active surface chemistry and the possibility of interface bond formation, leading to an increase in the number of electron-transfer reactions. © 2011 American Chemical Society

Tribological performance of Zinc soft metal coatings in solid lubrication

Science.gov (United States)

Regalla, Srinivasa Prakash; Krishnan Anirudh, V.; Reddy Narala, Suresh Kumar

2018-04-01

Solid lubrication by soft coatings is an important technique for superior tribological performance in machine contacts involving high pressures. Coating with soft materials ensures that the subsurface machine component wear decreases, ensuring longer life. Several soft metal coatings have been studied but zinc coatings have not been studied much. This paper essentially deals with the soft coating by zinc through electroplating on hard surfaces, which are subsequently tested in sliding experiments for tribological performance. The hardness and film thickness values have been found out, the coefficient of friction of the zinc coating has been tested using a pin on disc wear testing machine and the results of the same have been presented.

Zinc blotting assay for detection of zinc binding prolamin in barley (Hordeum vulgare) grain

DEFF Research Database (Denmark)

Uddin, Mohammad Nasir; Nielsen, Ane Langkilde-Lauesen; Vincze, Eva

2014-01-01

In plants, zinc is commonly found bound to proteins. In barley (Hordeum vulgare), major storage proteins are alcohol-soluble prolamins known as hordeins, and some of them have the potential to bind or store zinc. 65Zn overlay and blotting techniques have been widely used for detecting zinc......-binding protein. However, to our knowledge so far this zinc blotting assay has never been applied to detect a prolamin fraction in barley grains. A radioactive zinc (65ZnCl2) blotting technique was optimized to detect zinc-binding prolamins, followed by development of an easy-to-follow nonradioactive colorimetric...... zinc blotting method with a zinc-sensing dye, dithizone. Hordeins were extracted from mature barley grain, separated by SDS-PAGE, blotted on a membrane, renatured, overlaid, and probed with zinc; subsequently, zinc-binding specificity of certain proteins was detected either by autoradiography or color...

Silver-zinc electrodeposition from a thiourea solution with added EDTA or HEDTA

International Nuclear Information System (INIS)

Oliveira, G.M. de; Carlos, I.A.

2009-01-01

This paper shows the study of silver-zinc electrodeposition from a thiourea solution with added (ethylenedinitrilo)tetraacetic acid (EDTA), disodium salt and N-(2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), trisodium salt. Voltammetric results indicated that silver-zinc alloy can be obtained applying overpotential higher than 0.495 V, in Tu solution containing 1.0 x 10 -1 mol L -1 Zn(NO 3 ) 2 + 2.5 x 10 -2 mol L -1 AgNO 3 . This was due to silver(I) ion complexation with thiourea, which shifted the silver deposition potential to more negative value and due to silver-zinc alloy deposition, which occurred at potentials more positive than the potential to zinc deposition alone. EDTA or HEDTA did not significantly affect the silver and zinc deposition potentials, but decreased the current density for silver-zinc deposition. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses of the silver-zinc deposits showed that the morphology and composition changed as a function of the conditions of deposition, viz, deposition potential (E d ), deposition charge density (q d ) and solution composition (silver, EDTA and HEDTA concentrations). EDS analysis of the deposits showed sulphur (S) incorporated into the silver-zinc deposit, while SEM images showed that this sulphur content seemed to improve the silver-zinc morphology, as did the presence of EDTA and HEDTA in the solution, which enhanced the sulphur incorporation into the silver-zinc deposit. X-ray diffraction (XRD) analysis of the silver-zinc deposit showed that it was amorphous, irrespective of its composition and morphology

Surface reaction of SnII on goethite (α-FeOOH): surface complexation, redox reaction, reductive dissolution, and phase transformation.

Science.gov (United States)

Dulnee, Siriwan; Scheinost, Andreas C

2014-08-19

To elucidate the potential risk of (126)Sn migration from nuclear waste repositories, we investigated the surface reactions of Sn(II) on goethite as a function of pH and Sn(II) loading under anoxic condition with O2 level redox state and surface structure were investigated by Sn K edge X-ray absorption spectroscopy (XAS), goethite phase transformations were investigated by high-resolution transmission electron microscopy and selected area electron diffraction. The results demonstrate the rapid and complete oxidation of Sn(II) by goethite and formation of Sn(IV) (1)E and (2)C surface complexes. The contribution of (2)C complexes increases with Sn loading. The Sn(II) oxidation leads to a quantitative release of Fe(II) from goethite at low pH, and to the precipitation of magnetite at higher pH. To predict Sn sorption, we applied surface complexation modeling using the charge distribution multisite complexation approach and the XAS-derived surface complexes. Log K values of 15.5 ± 1.4 for the (1)E complex and 19.2 ± 0.6 for the (2)C complex consistently predict Sn sorption across pH 2-12 and for two different Sn loadings and confirm the strong retention of Sn(II) even under anoxic conditions.

Influence of silane films in the zinc coating post-treatment

International Nuclear Information System (INIS)

Costa, Marlla Vallerius da; Menezes, Tiago Lemos; Malfatti, Celia de Fraga; Muller, Iduvirges Lourdes; Oliveira, Claudia Trindade; Bonino, Jean-Pierre

2009-01-01

The sol-gel process based on silanes precursors appeared in recent years as a strong alternative for post-treatment to provide an optimization of the protective efficacy of zinc. Moreover, this process has been used to replace chemical chromating conversion based on hexavalent chromium. The silane films are hybrid compounds that provide characteristics of both polymeric materials, such as flexibility and functional compatibility, and ceramic materials, such as high strength and durability. The present work aimed to evaluate the influence of silane films obtained by dip-coating, on the characteristics of electrodeposited zinc coatings. The xerogel films showed a homogeneous surface and a better performance on the corrosion resistance than zinc coating without post-treatment, what can be confirmed by the electrochemical impedance results. These tests showed that application of the silane film promotes the occurrence of one more time constant compared to pure zinc system, hindering the corrosion process. (author)

Incorporation of zinc into the coccoliths of the microalga Emiliania huxleyi.

Science.gov (United States)

Santomauro, Giulia; Sun, Wei-Lin; Brümmer, Franz; Bill, Joachim

2016-04-01

The coccolithophore Emiliania huxleyi is covered with elaborated calcite plates, the so-called coccoliths, which are produced inside the cells. We investigated the incorporation of zinc into the coccoliths of E. huxleyi by applying different zinc and calcium amounts via the culture media and subsequently analyzing the zinc content in the cells and the Zn/Ca ratio of the coccoliths. To investigate the Zn/Ca ratio of coccoliths built in the manipulated media, the algae have first to be decalcified, i.e. coccolith free. We used a newly developed decalcification method to obtain 'naked' cells for cultivation. E. huxleyi proliferated and produced new coccoliths in all media with manipulated Zn/Ca ratios. The cells and the newly built coccoliths were investigated regarding their zinc content and their Zn/Ca ratio, respectively. High zinc amounts were taken up by the algae. The Zn/Ca ratio of the coccoliths was positively correlated to the Zn/Ca ratio of the applied media. The unique feature of the coccoliths was maintained also at high Zn/Ca ratios. We suggest the following pathway of the zinc ions into the coccoliths: first, the zinc ions are bound to the cell surface, followed by their transportation into the cytoplasm. Obviously, the zinc ions are removed afterwards into the coccolith vesicle, where the zinc is incorporated into the calcite coccoliths which are then extruded. The incorporation of toxic zinc ions into the coccoliths possibly due to a new function of the coccoliths as detoxification sites is discussed.

Study on a corrosion products behavior with zinc injection in PWR primary circuit based on the crud investigation in actual plant

International Nuclear Information System (INIS)

Hisamune Kenji; Nambu Tohru; Akutagawa Daisuke; Nagata Nobuaki; Shimizu, Yuichi; Nagamine, Kunitaka; Kogawa Noritaka

2012-09-01

Zinc injection into the reactor coolant of Pressurized Water Reactor (PWR) is one of the most effective techniques for removing radioactive cobalt from the chromite type spinel oxides in the inner layer of reactor coolant component surfaces. Many documents have reported that zinc injection applied plants have generally achieved positive dose rate reduction effects for the reactor coolant components and piping. Tsuruga Nuclear Power Plant unit 2 (hereafter Tsuruga unit 2) which applied zinc injection in 2005 has also achieved good dose reduction effects in most primary coolant piping. However, some piping without dose-rate reduction effects exist, it has come to an issue to plan radiation exposure reduction measures for the works around relevant piping. To plan a reasonable dose-rate reduction measures for respective components and piping in primary systems, it is considered necessary to understand the dose-rate reduction effects of zinc injection mechanically. Therefore, the surface oxides/deposits on piping and fuel cladding tubes with operational histories under zinc injection were investigated. As a result of the investigation, the changes in specific aspects of oxide layers and CRUDs are found as follow: - Owing to long-term zinc injection, deposits and oxides on the primary coolant piping are extremely reduced, the boundary between the outer oxide layer and the inner oxide layer become unclear with the thinning of the outer oxide layers. - At a Pressurizer Spray Piping, the dose-rate increases than before zinc injection. The oxide layers have the same 3-layer construction as before zinc injection, and the surface concentration of the radioactive cobalt is high. - At the fuel cladding tube surfaces, what is observed is the amount of metal nickel decrease and the chromium composition increase in the spinel type oxide From these results, it is suggested that, the oxide layers composed principally of zinc chromite spinel grow up on the pipe surface with zinc

Zinc in human serum

International Nuclear Information System (INIS)

Kiilerich, S.

1987-01-01

The zinc ion is essential for the living organism. Many pathological conditions have been described as a consequence of zinc deficiency. As zinc constitutes less than 0.01 per cent of the body weight, it conventionally belongs to the group of trace elements. The method of atomic absorption spectrophotometry is used to measure the concentration of zinc in serum and urine from healthy persons. The assumptions of the method is discussed. The importance of proteinbinding, diet and the diurnal variation of serum zinc concentration is presented. Serum versus plasma zinc concentration is discussed. Reference serum zinc values from 104 normal subjects are given. Zinc in serum is almost entirely bound to proteins. A preliminary model for the estimation of the distribution of zinc between serum albumin and α 2 -macroglobulin is set up. This estimate has been examined by an ultracentrufugation method. The binding of zinc to a α 2 -macroglobulin in normal persons is appoximately 7 per cent, in patients with cirrhosis of the liver of alcoholic origin approximately 6 per cent, in patients with insulin dependent diabetes mellitus approximately 5 per cent, and in patients with chronic renal failure approximately 2 per cent. It is concluded, therefore, that for clinical purposes it is sufficient to use the concentration of total serum zinc corrected for the concentration of serum albumin. (author)

Functional and community-level soil microbial responses to zinc addition may depend on test system biocomplexity.

NARCIS (Netherlands)

Sverdrup, L.E.; Linjordet, R.; Stomman, G.; Hagen, S.B.; van Gestel, C.A.M.; Frostegard, A.; Sorheim, R.

2006-01-01

The effect of zinc on soil nitrification and composition of the microbial community in soil was investigated using a full factorial experiment with five zinc concentrations and four levels of biological complexity (microbes only, microbes and earthworms (Eisenia fetida), microbes and Italian

Synthesis, photophysical and photochemical properties of zinc phthalocyanines bearing fluoro-functionalized substituents

International Nuclear Information System (INIS)

Aktaş, Ayşe; Pişkin, Mehmet; Durmuş, Mahmut; Bıyıklıoğlu, Zekeriya

2014-01-01

In this study, the synthesis of phthalonitrile derivatives bearing fluoro-functionalized groups and their peripherally-tetra substituted zinc phthalocyanine complexes were reported. The phthalonitrile derivatives 2a–5a were prepared by nucleophilic substitution of 4-nitrophthalonitrile with 2-[3-(trifluoromethyl)phenoxy]ethanol, 2-{2-[3-(trifluoromethyl) phenoxy]ethoxy}ethanol, 2-(2,3,5,6-tetrafluorophenoxy)ethanol, 2-[2-(2,3,5,6-tetrafluorophenoxy)ethoxy]ethanol, respectively. Zinc phthalocyanines bearing fluoro-functionalized groups (2b–5b) were obtained from the corresponding phthalonitrile derivatives. The newly synthesized phthalocyanines displayed good solubility in organic solvents such as chloroform (CHCl 3 ), dichloromethane (DCM), tetrahydrofuran (THF), toluene, dimethylformamide (DMF) and dimethylsulfoxide (DMSO). On the other hand, the singlet oxygen, photodegradation, fluorescence quantum yields and fluorescence lifetime of these complexes were determined in DMSO. The effects of the substitution with fluoro-functionalized groups on these parameters were also compared. -- Highlights: • Synthesis of peripherally substituted zinc phthalocyanines. • Photophysical and photochemical properties in DMSO for phthalocyanines. • Photodynamic therapy studies

Synthesis, photophysical and photochemical properties of zinc phthalocyanines bearing fluoro-functionalized substituents

Energy Technology Data Exchange (ETDEWEB)

Aktaş, Ayşe [Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Pişkin, Mehmet [Marmara University, Faculty of Art and Science, Department of Chemistry, 34722 Kadikoy-Istanbul (Turkey); Durmuş, Mahmut [Gebze Institute of Technology, Department of Chemistry, PO Box 141, Gebze 41400, Kocaeli (Turkey); Bıyıklıoğlu, Zekeriya, E-mail: zekeriya_61@yahoo.com [Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey)

2014-01-15

In this study, the synthesis of phthalonitrile derivatives bearing fluoro-functionalized groups and their peripherally-tetra substituted zinc phthalocyanine complexes were reported. The phthalonitrile derivatives 2a–5a were prepared by nucleophilic substitution of 4-nitrophthalonitrile with 2-[3-(trifluoromethyl)phenoxy]ethanol, 2-{2-[3-(trifluoromethyl) phenoxy]ethoxy}ethanol, 2-(2,3,5,6-tetrafluorophenoxy)ethanol, 2-[2-(2,3,5,6-tetrafluorophenoxy)ethoxy]ethanol, respectively. Zinc phthalocyanines bearing fluoro-functionalized groups (2b–5b) were obtained from the corresponding phthalonitrile derivatives. The newly synthesized phthalocyanines displayed good solubility in organic solvents such as chloroform (CHCl{sub 3}), dichloromethane (DCM), tetrahydrofuran (THF), toluene, dimethylformamide (DMF) and dimethylsulfoxide (DMSO). On the other hand, the singlet oxygen, photodegradation, fluorescence quantum yields and fluorescence lifetime of these complexes were determined in DMSO. The effects of the substitution with fluoro-functionalized groups on these parameters were also compared. -- Highlights: • Synthesis of peripherally substituted zinc phthalocyanines. • Photophysical and photochemical properties in DMSO for phthalocyanines. • Photodynamic therapy studies.

Impact of residual elements on zinc quality in the production of zinc oxide

Czech Academy of Sciences Publication Activity Database

Luptáková, Natália; Dymáček, Petr; Pešlová, F.; Jurkovič, Z.; Barborák, O.; Stodola, J.

2016-01-01

Roč. 55, č. 3 (2016), s. 407-410 ISSN 0543-5846 Institutional support: RVO:68081723 Keywords : zinc * metallography * microstructure of zinc * zinc oxide * production of zinc oxide Subject RIV: JG - Metallurgy Impact factor: 0.959, year: 2014

Hydrothermal synthesis of zinc oxide nanoparticles using rice as soft biotemplate.

Science.gov (United States)

Ramimoghadam, Donya; Bin Hussein, Mohd Zobir; Taufiq-Yap, Yun Hin

2013-01-01

Rice as a renewable, abundant bio-resource with unique characteristics can be used as a bio-template to synthesize various functional nanomaterials. Therefore, the effect of uncooked rice flour as bio-template on physico-chemical properties, especially the morphology of zinc oxide nanostructures was investigated in this study. The ZnO particles were synthesized through hydrothermal-biotemplate method using zinc acetate-sodium hydroxide and uncooked rice flour at various ratios as precursors at 120°C for 18 hours. The results indicate that rice as a bio-template can be used to modify the shape and size of zinc oxide particles. Different morphologies, namely flake-, flower-, rose-, star- and rod-like structures were obtained with particle size at micro- and nanometer range. Pore size and texture of the resulting zinc oxide particles were found to be template-dependent and the resulting specific surface area enhanced compared to the zinc oxide synthesized without rice under the same conditions. However, optical property particularly the band gap energy is generally quite similar. Pure zinc oxide crystals were successfully synthesized using rice flour as biotemplate at various ratios of zinc salt to rice. The size- and shape-controlled capability of rice to assemble the ZnO particles can be employed for further useful practical applications.

Comparison of drug delivery potentials of surface functionalized cobalt and zinc ferrite nanohybrids for curcumin in to MCF-7 breast cancer cells

International Nuclear Information System (INIS)

Sawant, V.J.; Bamane, S.R.; Shejwal, R.V.; Patil, S.B.

2016-01-01

The functionalization and surface engineering of CoFe 2 O 4 and ZnFe 2 O 4 nanoparticles were performed by coating with PEG and Chitosan respectively using simple wet co-precipitation. Then multiactive therapeutic drug curcumin was loaded to form drug delivery nanohybrids by precipitation. These nanohybrids were characterized separately using UV–vis, FTIR, PL spectroscopy, XRD, VSM, SEM and TEM analysis. The moderate antibacterial activities of the nanohybrids were elaborated by in vitro antibacterial screening on Escherichia coli and Staphylococcus aureus. The anticancer potentials, apoptotic effects and enhanced drug delivery properties of these nanohybrids were confirmed and compared on MCF-7 cells by in vitro MTT assay. The drug delivery activities for hydrophobic drug and anticancer effects of chitosan coated zinc ferrite functionalized nanoparticles were higher than PEG coated cobalt ferrite nanohybrids. - Highlights: • CoFe 2 O 4 and ZnFe 2 O 4 nanoparticles were surface functionalized with PEG and Chitosan respectively. • Hydrophobic multi therapeutic anticancer drug curcumin was loaded into these nanohybrids and their structure, morphologies were confirmed. • The effects of PEG and Chitosan coating over ferrites for curcumin release have been elaborated, and the Chitosan coated curcumin loaded Zinc ferrite nanohybrid exhibited higher drug delivery and anticancer effects.

Comparison of drug delivery potentials of surface functionalized cobalt and zinc ferrite nanohybrids for curcumin in to MCF-7 breast cancer cells

Energy Technology Data Exchange (ETDEWEB)

Sawant, V.J., E-mail: v11131@rediffmail.com [Department of Chemistry, Smt.K.W.College, Sangli, MS 416416 (India); Bamane, S.R. [Department of Chemistry, Raja Shripatrao Bhagwantrao College, Aundh, Satara, MS (India); Shejwal, R.V. [L.B.S. College, Satara, MS (India); Patil, S.B. [A.Birnale College of Pharmacy, Sangli, MS (India)

2016-11-01

The functionalization and surface engineering of CoFe{sub 2}O{sub 4} and ZnFe{sub 2}O{sub 4} nanoparticles were performed by coating with PEG and Chitosan respectively using simple wet co-precipitation. Then multiactive therapeutic drug curcumin was loaded to form drug delivery nanohybrids by precipitation. These nanohybrids were characterized separately using UV–vis, FTIR, PL spectroscopy, XRD, VSM, SEM and TEM analysis. The moderate antibacterial activities of the nanohybrids were elaborated by in vitro antibacterial screening on Escherichia coli and Staphylococcus aureus. The anticancer potentials, apoptotic effects and enhanced drug delivery properties of these nanohybrids were confirmed and compared on MCF-7 cells by in vitro MTT assay. The drug delivery activities for hydrophobic drug and anticancer effects of chitosan coated zinc ferrite functionalized nanoparticles were higher than PEG coated cobalt ferrite nanohybrids. - Highlights: • CoFe{sub 2}O{sub 4} and ZnFe{sub 2}O{sub 4} nanoparticles were surface functionalized with PEG and Chitosan respectively. • Hydrophobic multi therapeutic anticancer drug curcumin was loaded into these nanohybrids and their structure, morphologies were confirmed. • The effects of PEG and Chitosan coating over ferrites for curcumin release have been elaborated, and the Chitosan coated curcumin loaded Zinc ferrite nanohybrid exhibited higher drug delivery and anticancer effects.

Zinc-Containing Hydroxyapatite Enhances Cold-Light-Activated Tooth Bleaching Treatment In Vitro

Science.gov (United States)

Shi, Xinchang

2017-01-01

Cold-light bleaching treatment has grown to be a popular tooth whitening procedure in recent years, but its side effect of dental enamel demineralization is a widespread problem. The aim of this study was to synthesize zinc-substituted hydroxyapatite as an effective biomaterial to inhibit demineralization or increase remineralization. We synthesized zinc-substituted hydroxyapatite containing different zinc concentrations and analysed the product using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and energy dispersive spectrometer (EDS). The biological assessment of Zn-HA was conducted by CCK-8 assay and bacterial inhibition tests. pH cycling was performed to estimate the effect of Zn-HA on the enamel surface after cold-light bleaching treatment. The XRD, FTIR, and EDS results illustrated that zinc ions and hydroxyapatite combined in two forms: (1) Zn2+ absorbed on the surface of HA crystal and (2) Zn2+ incorporated into the lattice of HA. The results indicated that 2% Zn-HA, 4% Zn-HA, and 8% Zn-HA effectively inhibited the growth of bacteria yet showed poor biocompatibility, whereas 1% Zn-HA positively affected osteoblast proliferation. The XRD and scanning electron microscopy (SEM) results showed that the use of Zn-HA in pH cycling is obviously beneficial for enamel remineralization. Zinc-substituted hydroxyapatite could be a promising biomaterial for use in cold-light bleaching to prevent enamel demineralization. PMID:29159178

Zinc-Containing Hydroxyapatite Enhances Cold-Light-Activated Tooth Bleaching Treatment In Vitro

Directory of Open Access Journals (Sweden)

Yi Li

2017-01-01

Full Text Available Cold-light bleaching treatment has grown to be a popular tooth whitening procedure in recent years, but its side effect of dental enamel demineralization is a widespread problem. The aim of this study was to synthesize zinc-substituted hydroxyapatite as an effective biomaterial to inhibit demineralization or increase remineralization. We synthesized zinc-substituted hydroxyapatite containing different zinc concentrations and analysed the product using X-ray diffraction (XRD, Fourier transform infrared (FTIR spectroscopy, and energy dispersive spectrometer (EDS. The biological assessment of Zn-HA was conducted by CCK-8 assay and bacterial inhibition tests. pH cycling was performed to estimate the effect of Zn-HA on the enamel surface after cold-light bleaching treatment. The XRD, FTIR, and EDS results illustrated that zinc ions and hydroxyapatite combined in two forms: (1 Zn2+ absorbed on the surface of HA crystal and (2 Zn2+ incorporated into the lattice of HA. The results indicated that 2% Zn-HA, 4% Zn-HA, and 8% Zn-HA effectively inhibited the growth of bacteria yet showed poor biocompatibility, whereas 1% Zn-HA positively affected osteoblast proliferation. The XRD and scanning electron microscopy (SEM results showed that the use of Zn-HA in pH cycling is obviously beneficial for enamel remineralization. Zinc-substituted hydroxyapatite could be a promising biomaterial for use in cold-light bleaching to prevent enamel demineralization.

Cyclic AMP Pathway Activation and Extracellular Zinc Induce Rapid Intracellular Zinc Mobilization in Candida albicans

Science.gov (United States)

Kjellerup, Lasse; Winther, Anne-Marie L.; Wilson, Duncan; Fuglsang, Anja T.

2018-01-01

Zinc is an essential micronutrient, required for a range of zinc-dependent enzymes and transcription factors. In mammalian cells, zinc serves as a second messenger molecule. However, a role for zinc in signaling has not yet been established in the fungal kingdom. Here, we used the intracellular zinc reporter, zinbo-5, which allowed visualization of zinc in the endoplasmic reticulum and other components of the internal membrane system in Candida albicans. We provide evidence for a link between cyclic AMP/PKA- and zinc-signaling in this major human fungal pathogen. Glucose stimulation, which triggers a cyclic AMP spike in this fungus resulted in rapid intracellular zinc mobilization and this “zinc flux” could be stimulated with phosphodiesterase inhibitors and blocked via inhibition of adenylate cyclase or PKA. A similar mobilization of intracellular zinc was generated by stimulation of cells with extracellular zinc and this effect could be reversed with the chelator EDTA. However, zinc-induced zinc flux was found to be cyclic AMP independent. In summary, we show that activation of the cyclic AMP/PKA pathway triggers intracellular zinc mobilization in a fungus. To our knowledge, this is the first described link between cyclic AMP signaling and zinc homeostasis in a human fungal pathogen. PMID:29619016

Reactivation in vitro of zinc-requiring apo-enzymes by rat liver zinc-thionein