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A double accumulation and stripping steps were proposed to increase the sensitivity of Co(II) determination by catalytic adsorptive stripping voltammetry (AdSV). Electrodes with large and small surface area were used for the first and second accumulation step, respectively. As the accumulation of Co(II) complex at the first electrode was finished, the electrode was placed at a short distance opposite the second one. Then the Co(II) complex desorbed from the first electrode was accumulated at the second electrode. Taking into account the small volume of space between the electrodes, the concentration of the Co(II) complex in solution between the electrodes was drastically higher than that in the bulk solution. The accumulation step at the second electrode was performed from the solution with higher concentration of Co(II) and therefore the detection limit was lowered. The calibration graph of Co(II) determination for accumulation time of 120 s at both electrodes was linear from 1.18 to 58.9 ng L−1. The detection limit for Co(II) was equal to 0.47 ng L−1and it is so far the lowest detection limit obtained for Co(II) using mercury-free electrodes. The proposed method was applied to Co(II) determination in water certified reference material. [ABSTRACT FROM PUBLISHER]

In this work, dioctyl phthalate (Dop) was used as a highly plasticizing material to coat and link the surface of basic cellulose (Cel) with baker's yeast for the formation of a novel modified cellulose biosorbent (Cel-Dop-Yst). Characterization was accomplished by Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric analysis (TGA) and Scanning Electron Microscope (SEM) measurements. The feasibility of using Cel-Dop-Yst biosorbent as an efficient material for removal of Co(II), Cu(II), Cd(II), Hg(II) and Pb(II) ions was explored using the batch equilibrium technique along with various experimental controlling parameters. The optimum pH values for removal of these metal ions were characterized in the range of 5.0–7.0. Cel-Dop-Yst was identified as a highly selective biosorbent for removal of the selected divalent metal ions. The Cel-Dop-Yst biosorbent was successfully implemented in treatment and removal of these divalent metal ions from industrial wastewater, sea water and drinking water samples using a multistage microcolumn technique. [ABSTRACT FROM AUTHOR]

An organic–inorganic hybrid supramolecular complex, (H3O)4[(CoC14H12N2O10)1.5(SiW12O40)]·2H2O, is constructed by tungstosilicate anion and 2,3-pyridinedicarboxylic acid cobalt coordination complex via intermolecular forces. Crystal data of the title complex: trigonal system,P-3c1space group,a = 20.363(3) Å,b = 20.363(3) Å,c = 27.685(5) Å,? = 90 °,? = 90 °,? = 90 °,V = 9942(3) Å3,Z = 4,Rint = 0.0383,R2 = 0.1645, GOOF = 1.083. The complex has been hydrothermally synthesized and characterized by Infrared spectra, TG-DTA, fluorescence, cyclic voltammetry, and single-crystal X-ray diffraction. The complex exhibits good catalytic activity for elimination of methanol in the gas phase, when the initial concentration of methanol is 2.76 g m?3, and flow rate is 10 mL min?1at 140 °C, the elimination rate of methanol is 82.6% over 0.2 g of complex. Catalytic performance [ABSTRACT FROM AUTHOR]

Macro-X-ray fluorescence (XRF) is a newly commercially available research tool very useful in the examination of artwork. Its novelty lies in its ability to create maps of the distribution of chemical elements on scales of a few milimetres. In this contribution, its use together with optical coherence tomography (OCT) in the inspection of an illuminated manuscript is reported for the first time. The former technique is used both for mapping the elemental distribution over large parts of the folios - including illuminated initials - and for quantitative analysis of the composition of the smalt pigment, as well as of changes in the composition of iron-gall ink at different pages. The latter, by providing cross-sectional images of painted details, helps in interpreting the XRF results. All of the results shown relate to the examination of a late sixteenth-century-illuminated parchment manuscript (a gradual) originating from the Convent of the Benedictine Sisters in Lviv in the Ukraine. [ABSTRACT FROM AUTHOR]

In vivocytogenetical assay in root meristems has been carried out to study the effect of cobalt and cobalt oxide nanos on active mitotic index and chromosomal aberrations of green manure crop, Sesbania pea. Nanoparticles are nanosize particles and can enter freely into the cells and can interfere in cell's normal function. Studies to justify its probable after-effects on living beings are scarce. So it is important to study its effect on living beings. For this purpose, seeds ofSesbania cannabinavariety ND-1 were soaked in distilled water for 14 hours and after soaking, the seeds were treated with three different treatments, namely, nano-cobalt, nano-cobalt oxide and ethanol for three hours. The treated root meristems exhibited various types of chromosomal aberrations such as metaphasic plate distortion, unorientation at metaphase, breaking of chromosomes, fragmentation, spindle dysfunctioning, stickiness, scattering, precocious movement at metaphase and bridge, unequal separation, multiple bridge, fragmentation, scattering, laggard and unorientation at anaphase, etc. [ABSTRACT FROM AUTHOR]

We investigate the binding of the cobalt atom on small aromatic model systems as a proxy for interaction with graphene, using density functional theory, coupled-cluster theory, and combinations of them using projector-based quantum embedding. We set out in some detail the electronic structure of the cobalt atom alone, because some nuances of atomic structure appear to have been overlooked in previous studies. Two states of the complex in particular are studied: those formed from thea 4F ground state of the atom; and fromc 2D, the lowest doublet state with configuration 3d94s0. We highlight the difficulties in extracting reliable results from typical approximate density functionals, and demonstrate that embedding calculations using the coupled-cluster theory in an active subsystem greatly reduce functional dependence, and produce a picture more consistent with the available experimental information. Our results cast doubt on previous calculations that have predicted strong chemisorptive binding between graphene and thec 2D state of cobalt. [ABSTRACT FROM PUBLISHER]

Cobalt (Co) can stimulate erythropoietin production in individuals at doses exceeding 25 mg CoCl2/day. Co has also been shown to exert effects on the thyroid gland, heart and nervous system at sufficient doses. The biological activity of Co is dictated by the concentration of free (unbound) ionic Co2+. Blood concentrations, as well as, urinary excretion rates of Co are reliable biomarkers for systemic Co exposure. A recent series of human volunteer Co-supplement studies simultaneously measured Co blood and urine concentrations, as well as, Co speciation in serum, and a number of biochemical and clinical parameters. It was found in these studies that peak Co whole blood concentration as high as 117 μg/L were not associated with changes in hematological parameters such as increased red blood cell (RBC) count, hemoglobin (Hgb) or hematocrit (Hct) levels, nor with changes in cardiac, neurological or, thyroid function. Using a Co biokinetic model, the estimated Co systemic tissue concentrations (e.g., liver, kidney, and heart) following 90-days of Co-dietary supplementation with ∼1 mg Co/day were found to be similar to estimated tissue concentrations in implant patients after 10 years of exposure at continuous steady state Co blood concentration of ∼10 μg/L. This study is the first to present modeled Co tissue concentrations at various doses following sub-chronic and chronic exposure. The modeled steady state tissue Co concentrations in combination with the data on adverse health effects in humans should help in the characterization of potential hazards associated with increased blood Co concentrations due to exposure to dietary supplements or cobalt-chromium (Co-Cr) containing implants. [ABSTRACT FROM AUTHOR]

The as-cast Co-Cr-Mo alloy (ASTM F75) has been widely used as biomaterial in orthopaedic implant because of its excellent mechanical properties, good corrosion resistance and biocompatibility. However, some defects such as porosity and pinhole in an as-cast make some problems for application. Therefore in this study, the cobalt-aluminate (CoAl2O4) used as an inoculant during coating plays to refine the grain size and to reduce the porosity and pinhole content in an as-cast. Therefore, the effect of an inoculant addition on defect content, microstructure and mechanical properties of as-cast Co-Cr-Mo alloy has been investigated. The mechanical properties of the Co-Cr-Mo alloy were improved by addition of an inoculant. [ABSTRACT FROM AUTHOR]

To avoid the activated radiation of elemental cobalt and meet the requirements of critical working conditions in which operate the sealing surface of nuclear-power valves, a new cobalt-free Ni-based alloy (Ni-SD) was developed. The powder was deposited on a stainless-steel substrate by a novel hollow laser beam cladding technique. The experimental results reveal that the micro-hardness of Ni-SD can approach 700 HV0·3, which is much higher than that of the common Co-based alloy Stellite6 (500 HV0·3) that is currently used in nuclear-power valves. Analytical results indicate that γ-Ni is the primary phase in the Ni-SD coating and that it proportionally dissolves metallic and non-metallic elements. In addition, the Ni-SD coating contains some hard phases, such as carbides and borides. High-temperature measurements indicate that the Ni-SD alloy offers excellent advantages such as high wear resistance and high-temperature operation. [ABSTRACT FROM AUTHOR]

It is of much significance to control the morphology and size of cobalt oxalate precursor for the preparation of cobalt powders. The cobalt oxalate powders were prepared by conventional precipitation at different initial cobalt chloride concentrations in the presence of pulsed electromagnetic field. Scanning electron microscopy images and size analysis indicate that spherical and fine cobalt oxalate particles with uniform size are obtained. Conductivity analysis demonstrates that pulsed electromagnetic field plays an important role in the preparation of monodisperse cobalt oxalate particles owing to the inhibition of the secondary nucleation. X-ray powder diffraction results show the formation of β-CoC2O4·2H2O with a micro-size change of cobalt oxalate grain when the extra pulsed electromagnetic field is present. Fourier transform infrared spectroscopy results indicate that the transition of bond way in CoC2O4·2H2O favours to develop stable crystal nucleus. Besides, a possible mechanism for the interaction between pulsed electromagnetic field and cobalt oxalate reaction system was preliminarily discussed. [ABSTRACT FROM AUTHOR]

(x= 0.12) nanofibres have been successfully prepared by sol-gel method, electrospinning and subsequent heat treatment. The prepared nanofibres were characterised via X-ray diffraction (XRD), transmission electron micrograph (TEM) and superconducting quantum interference device (SQUID). The XRD revealed that the crystal structure of samples was hexagonal magnetoplumbite structure at calcination temperature from 900 °C to 1100 °C. The TEM showed that the ferrite nanofibres had a smooth morphology and a bamboo joint structure, and the diameter of nanofibres increased with the increase of sintering temperature. The SQUID revealed that there were some intriguing changes in magnetic properties with the variation of sintering temperature or altering calcination time, and the optimised magnetic property of samples wasMs70.76 emu/g,Mr36.35 emu/g andHc6.26 kOe at 950 °C for 2 h, the corresponding grain size was 39.30 nm. Meanwhile, the nanofibres display more significant improvements in the magnetic properties than the nanoparticles obtained by the sol-gel process, which was probably due to the anisotropic morphology and the cylindrical magnetic domain of ferrite nanofibres. [ABSTRACT FROM AUTHOR]

We present low-temperature magnetic properties for a high-quality polycrystalline sample of the first ferromagnetic superconductor Y9Co7. The results of susceptibility and magnetization measurements show the coexistence of a weak itinerant ferromagnetic order with a Curie temperature ofTC≅ 4.5 K and superconductivity belowTS = 3 K. Several electronic quantities and parameters characterizing the superconducting and normal state are calculated within the Ginzburg–Landau–Abrikosov–Gorkov theory. The data reveal clean limit superconductivity in Y9Co7due to the good chemical purity and structural order of the specimen. [ABSTRACT FROM PUBLISHER]

The aliphatic α-hydroxyoxime LIX®63 contains a secondary hydroxyl group that is susceptible to oxidation. In the present work, an alternative oxidation-resistant α-hydroxyoxime containing a tertiary hydroxyl group, namely (1-hydroxycyclohexyl)-phenyl ketone oxime (“phenyl oxime”), has been synthesized and characterized. Combining phenyl oxime with Versatic 10 results in synergistic metal extraction behavior. The ability of this ligand to withstand oxidation is demonstrated. Other benefits are also evident, including its existing wholly in the activeantiisomeric form and exhibiting fast nickel kinetics in the synergistic system. Phenyl oxime readily undergoes aqueous acid-catalyzed hydrolysis and so is not commercially practical. Addition of carbon side-chains could help to overcome this. [ABSTRACT FROM PUBLISHER]

A novel preconcentration technique termed suspension dispersive solid phase extraction (SDSPE) was developed for selective separation and preconcentration of cobalt, nickel, and copper in environmental water. The method is based on the reaction of zinc sulfate and sodium hydroxide to form zinc hydroxide. The suspension results from the dispersion of the fine particles of the sorbent in the aqueous sample. The complexes of metal ions in the bulk aqueous sample with 1-(2-pyridylazo)-2-naphthol (PAN) were loaded on sorbents. After extraction, phase separation was performed by centrifugation and the enriched analyte in the sedimented phase was eluted by methanol and determined by flame atomic absorption spectrometry. Key parameters such as the type and mass of sorbent, type and volume of eluent, concentration of the chelating agent, equilibration time, and sample volume were optimized and an enrichment factor of 20 was obtained with a sample volume of 40 mL. The limits of detection for Co, Ni, and Cu were 2.4, 1.7, and 1.5 µg L−1, respectively. The relative standard deviations were 4.3%, 2.7%, and 1.6% at 10 µg L−1for Co, Ni, and Cu, respectively. The method was successfully employed for the determination of these metals in environmental waters. [ABSTRACT FROM AUTHOR]

Co(II) and Cd(II) salts react with 3,5-bis(benzimidazol-1-ylmethyl)benzoic acid (HL) under hydrothermal conditions to yield two new complexes, [Co(L)(Cl)]n(1) and {[Cd(L)2]·2.5H2O}n(2), which have been characterized by single-crystal and powder X-ray diffractions, IR, element, and thermogravimetric analysis. Complexes1and2exhibit structural diversity dependent on different metal salts;1has 2-D undulating sheet-like structure with (63)hcbtopology and2is a 3-D 2-nodal (3,6)-connectedfluframework with ()2() topology. Luminescence of2was investigated. [ABSTRACT FROM AUTHOR]

Four cobalt(II) coordination polymers, {[Co(HO-BDC)(bbp)]}n(1), {[Co(HO-BDC)(bmbp)2]·(H2O)2}n(2), {[Co(HO-BDC)(bbb)]}n(3), and {[Co2(HO-BDC)2(bmbb)2]·(H2O)3}n(4), where HO-H2BDC = 5-hydroxyisophthalic acid, bbp = 1,3-bis(benzimidazol-1-yl)propane, bmbp = 1,3-bis(2-methyl-benzimidazol-1-yl)propane, bbb = 1,4-bis(benzimidazol-1-yl)butane, and bmbb = 1,4-bis(2-methyl-benzimidazol-1-yl)butane, have been synthesized and characterized by elemental analyses, IR spectra, single-crystal X-ray diffraction, thermogravimetric analyses, and fluorescence properties. Compounds1and3are 4-connected 2-D networks with (44·62) topology. Compound2is a 1-D chain, while4features a 1-D ladder. These 1-D and 2-D complexes are further connected by hydrogen bonds to form 3-D supramolecular architectures. Complexes1–4showed very strong yellow luminescence emission. Four new cobalt(II) coordination polymers have been synthesized and characterized by elemental analyses, IR spectra, single crystal X-ray diffraction andthermogravimetric analyses. These four complexes all showed very strong yellowluminescence emission. [ABSTRACT FROM AUTHOR]

Cobalt electrodeposits have been produced from two types of baths. In the bath containing cobalt sulphate, cobalt chloride and boric acid, saccharin is found effective as a brightener additive. In the bath containing cobalt sulphate, potassium chloride and potassium citrate, thiourea is found to be effective as a brightener additive. Results of solution characteristics such as conductivity of the electrolytes, cathode current efficiency and rate of deposition are compared. The effect of additives on brightness, roughness, orientation of the crystal, grain size and surface morphology of the cobalt deposits are reported. The X-ray diffraction pattern obtained for electrodeposited cobalt showed a polycrystalline nature with hexagonal close packed structure. A smooth uniform and pore free surface was observed under scanning electron microscopy and atomic force microscopy analysis. Potentiodynamic polarisation and electrochemical impedance measurements in sodium chloride solution showed that a higher corrosion resistance was observed for the deposit from the second type of bath containing an additive. [ABSTRACT FROM AUTHOR]

Background: Minerals, metals, clays and rocks were widely used by physicians in the past. However, it was and it is well known that some inorganic elements at high dosage may have curative effects but also serious toxicity. The effects at low or ultra-low concentrations, on the contrary, are less documented, but the idea that low dosage supplementation might be beneficial to human health is widespread even in the present period. Methods: The main information about aluminium, bismuth, cobalt, gold, lithium, nickel and silver was selected and evaluated from a vast body of medical literature. Results: In modern times, most elements are proposed for human use at levels comparable with normal dietary intake, probably for precautionary considerations. Conclusion: Some inorganic trace compounds might have unexpected effects at extremely low dosages, but scientific demonstrations of beneficial effects of supplementation are mostly not available in the medical literature. [ABSTRACT FROM AUTHOR]

We report the successful substitution of cobalt, nickel and copper for iron in the 1038-phase parent compoundyielding,and), respectively. Superconductivity is induced in Co and Ni doped compounds reaching critical temperatures up to 15 K, similar to known Pt substituted), whereas no superconductivity was detected in. The obtainedphase diagrams are very similar to those of other iron arsenide superconductors indicating rather universal behaviour despite the more complex structures of the 1038-type compounds, where the physics is primarily determined by the FeAs layer. [ABSTRACT FROM PUBLISHER]

Two new complexes involving 3,4-pyridinedicarboxylic acid (3,4-H2pdc), copper(II) and cobalt(II) complexes, {[Cu(3,4-Hpdc)2(H2O)2]·2dmso}n(1) and {[Co(3,4-Hpdc)2(H2O)2]·2H2O·2dmso}n(2) (dmso = dimethylsulfoxide), have been synthesized by the diffusion method and characterized by elemental analysis, IR spectroscopy, thermal analysis, powder and single-crystal X-ray diffraction analysis, and electron paramagnetic resonance (EPR). In both compounds, the metal coordination sphere is composed of atrans-MO4N2core and adopts a distorted octahedral geometry in accordance with X-ray diffraction and EPR results. 3,4-Hpdc−ligands bridge the metal centers giving two-dimensional (2-D) coordination polymers with four-connected uninodal nets of (4,4) topology. [ABSTRACT FROM AUTHOR]

Phytoremediation of contaminated calcareous desert land in the United Arab Emirates has been investigated. Soils from 12 northern UAE sites, suspected of metal contamination, were acid-extracted and analyzed by ICP-OES for Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. Twenty-two plants naturally growing at contaminated sites were sampled and analyzed for their uptake of Co, Cr, Cu, Mn, Ni, Pb, and Zn and eight commercially available plants, grown under controlled conditions, were also studied for their phytoextraction capabilities. The concentration of available Cr was found to be 1300 ± 150 mg/kg in the soil of the Ajman Industrial Zone and 80 ± 10 mg/kg of Pb was found at Bithna. Among the plants investigated,Portulaca oleraceaandIresine herbstiishowed potential for Cr(VI) and Pb(II) accumulation, respectively, with bioconcentration factors (BCF) greater than unity.Atriplex halimusaccumulated Co(II), Cr(III), and Cu(II) each with a BCF > 1. [ABSTRACT FROM AUTHOR]

Amorphous and nanocrystalline cobalt-tungsten coatings were electrodeposited from a citrate-ammonia bath on copper substrates. Both coatings showed a nodular surface morphology, but a microcrack network was observed in the amorphous coating. The cyclic voltammograms of both deposits revealed anodic and cathodic low-current plateaus around the open circuit potential, exhibiting a passive behaviour. Mott-Schottky analysis showed that the passive films exhibit n-type semiconductivity behaviour and that formed on the amorphous coating showed higher crystal defects. Electrochemical impedance spectroscopy revealed that the amorphous coating has higher corrosion resistance than the nanocrystalline one at both open circuit and anodic potentials. This was attributed to the higher pore resistance of passive film formed at the open circuit potential and more chemical stability of the amorphous coating which reduces its dissolution at the anodic potential. The plugging of the microcrack network in the amorphous coating by corrosion products eliminated the negative effect of microcracks. [ABSTRACT FROM AUTHOR]

The greenness of a chemical precipitation process was attempted in the synthesis of SnO2nanoparticles through the use of safe, environmental-benign citric acid as a chelating agent. Thermogravimetric analysis (TGA) of the precipitates was used to study thermal decomposition. Presence of functional groups was examined by Fourier Transform Infrared Spectroscopy (FTIR). Negligible traces of functional groups were detected after calcination at 800°C. Phase formation and the degree of crystallinity were probed by X-ray diffraction (XRD). The process with chelation by citric acid resulted in larger crystallite sizes compared to those from the non-chelated system. The morphology of the nanoparticles was investigated by transmission electron microscopy (TEM). Although the SnO2phase could not be obtained at ambient temperature due to oxidative constraint, chelation by citric acid did indeed reduce the calcination temperature required for the change in the oxidation number and thus emergence of the SnO2phase. Such results could be indicative of lessened energy requirement in the synthesis of SnO2nanoparticles. [ABSTRACT FROM AUTHOR]

In this study, it is shown that the rate of bond degradation due to ageing in hot & humid conditions can be significantly reduced by the use of a Cu–Zn–Co ternary alloy coating, compared to current compounds and normal brass-coated steel cord. To better understand the adhesion mechanism, X-ray photoelectron spectroscopy is used to investigate the adhesion interface upon hot and humid ageing. In addition, the effect of removal of cobalt salts from compound on static and dynamic rubber compound properties is studied: it is found that this leads to improved heat ageing resistance, slower crack growth rate and less hysteresis. Hence, the new Cu–Zn–Co ternary alloy coating for steel cord allows cobalt salts to be removed from tires, which makes tires more durable and eco-friendly. [ABSTRACT FROM AUTHOR]

Cobalt-rich slag from blister refining is leached with an oxidising acid, and Co3O4 powder is prepared by an ozonation-precipitation-calcination method after iron has been removed from the solution by the goethite process at different pH values. The effects of stirring speed, gas flow rate, ozone concentration, pH and solution temperature on the precipitation rate of cobalt are investigated. The solution pH has an obvious effect on the precipitation rate, as do the stirring speed, gas flow rate and ozone concentration, but the temperature has little effect. With almost all the cobalt precipitated from the solution, the losses of copper and zinc are about 10% and 1·5%, respectively. The cobalt is precipitated in the form of amorphous CoOOH, identified by X-ray diffraction and with some physicochemical properties similar to those of cobalt hydroxide. The amorphous CoOOH is transformed into spherical Co3O4 powder by the calcination treatment. [ABSTRACT FROM AUTHOR]

Schiff-cobalt (salenCo) and Schiff-chromate (salenCr) were synthesized and used as catalysts for copolymerizing of propylene oxide (PO) and CO2. The alternating copolymer of polycarbonate was successfully obtained under mild conditions in the presence of 4-(dimethylamino)-pyridine (DMAP) cocatalyst. The influences of DMAP amount, polymerization time, temperature, and CO2pressure on the copolymerization efficiency and selectivity to polycarbonate were investigated in the presence of catalysts. Under the optimized conditions, salenCo/DMAP exhibited an excellent catalytic efficiency with perfectly alternating copolymerization products (99% carbonate and more than 99% polycarbonate with head-to-tail linkage) and high selectivity to polycarbonate over cyclic carbonate (more than 99% polymeric product) without byproduct (polyether). While only 76% selectivity to polymer, 95% carbonate linkage, and 80% head-to-tail connection unit were obtained over salenCr/DMAP catalyst. Furthermore, the catalytic activity of salenCo was superior to that of salenCr, resulting in higher molecular weight, more regular microstructure, and higher stability of copolymer. [ABSTRACT FROM AUTHOR]

Objective: To compare the macro mean shear bond strength (SBS) and failure mode of three cements to two types of metal using mould-enclosed and non-enclosed cement specimens.Methods: Titanium and base metal cobalt-based substrates were finished with 50 ?m aluminium oxide. Two resin-modified glass-ionomers (Riva Luting Plus, Fuji Plus) and one resin cement (RelyX Unicem) were prepared as per manufacturers’ instructions. Metal mould-enclosed and non-enclosed cement specimens with a bonding area diameter of 3.5?mm were prepared and stressed to failure using a 2 mm blunt edge shear knife at a cross-head speed of 1?mm/min to determine mean SBS. The shear knife was placed against the surface of the substrate. Failure analysis of the failed interface was performed with a stereo microscope at 40× magnification.Results: Two-way Analysis of Variance demonstrated a significant difference in mean SBS between materials (p?=?0.004) and cement (p?=?0.001). There was also a significant interaction between method and cement on SBS,F(2,?170)?=?7.209,p?=?0.003. Post hoc Tukey tests demonstrated no significant difference for either resinmodified glass-ionomer cements (RMGIC) (p?=?0.864,p?=?0.620) when comparing non-enclosed and mould-enclosed test methods bonded to titanium. There was however a significant difference (p?

Electroless cobalt films were deposited from a neutral pH glycinate solution without additives using morpholine borane (MB) as a reducing agent. The rate of deposition rises with increase in concentration of solution components (Co ions, MB and glycine), and pH. The efficiency of cobalt discharge increases when the deposition is performed from the Co(II) complex with glycine. XPS data indicate that boron and oxygen are incorporated into the cobalt films. Two forms of boron (elemental and its oxide) were detected in the electrolessly deposited cobalt films. [ABSTRACT FROM AUTHOR]

In this article, we describe that mononuclear complexes composed of (5-chloro-2-hydroxybenzylidene)aminobenzenesulfonamides ( L1-3) of general formula (L2(M)2H2O, where M is Co, Cu, Zn, Ni or Mn) reduced epimastigote proliferation and were found cidal for trypomastigotes of Trypanosoma cruzi Y strain. Complexes C5 and C11 have IC50 of 2.7 ± 0.27 and 4.8 ± 0.47 µM, respectively, for trypomastigotes, when the positive control Nifurtimox, which is also an approved drug for Chagas disease, showed IC50 of 2.7 ± 0.25 µM. We tested whether these complexes inhibit the enzyme T. cruzi trypanothione reductase or acting as DNA binders. While none of these complexes inhibited trypanothione reductase, we observed some degree of DNA binding, albeit less pronounced than observed for cisplatin in this assay. Unfortunately, most of these complexes were also toxic for mouse splenocytes. Along with the present studies, we discuss a number of interesting structure-activity relationships and chemical features for these metal complexes, including computational calculations. [ABSTRACT FROM AUTHOR]

Subduction of the Bangong Meso-Tethys and collision between the Lhasa and Qiangtang blocks were important for the growth of Tibetan crust, as well as the development of super-large porphyry copper deposits in central Tibet. However, the initiation and closure timing, and nature and structure of the Bangong Meso-Tethys are still poorly constrained. Petrology, geochronology, and geochemistry of the Rebang Co and Julu ophiolites in the western part of the suture zone are used to constrain the tectonic history and structure of the Bangong Meso-Tethys. These two suites consist of ultramafic rocks, gabbro and diabase dikes, pillow basalts, and radiolarian cherts. Zircon U–Pb dating of zircon grains of gabbros yields well-defined weighted mean ages of 161.5 ± 1.5 Ma and 103.8 ± 3.9 Ma for the Rebang Co and Julu suites, respectively. Both of ophiolitic suites have mid-oceanic ridge basalt and island-arc tholeiite affinities, similar to back-arc basin crust. We suggest these suites formed above an intra-oceanic subduction zone at least during Middle Jurassic through mid-Cretaceous times. Along with coeval subduction beneath the southern Qiangtang margin, as well as fore-arc basin development, the Bangong Meso-Tethys has a complicated structure and history. Clearly, subduction in the Bangong Meso-Tethys was still active during mid-Cretaceous time and the Meso-Tethys did not close until Late Cretaceous time. [ABSTRACT FROM AUTHOR]

The mechanistic understanding of nanotoxicity requires the physico-chemical characterisation of nanoparticles (NP), and their comparative investigation relative to the corresponding ions and microparticles (MP). Following this approach, the authors studied the dissolution, interaction with medium components, bioavailability in culture medium, uptake and intracellular distribution of radiolabelled Co forms (CoNP, CoMP and Co2+) in Balb/3T3 mouse fibroblasts. Co2+ first saturates the binding sites of molecules in the extracellular milieu (e.g., albumin and histidine) and on the cell surface. Only after saturation, Co2+ is actively uptaken. CoNP, instead, are predicted to be internalised by endocytosis. Dissolution of Co particles allows the formation of Co compounds (CoNP-rel), whose mechanism of cellular internalisation is unknown. Co uptake (ranking CoMP > CoNP > Co2+) reached maximum at 4 h. Once inside the cell, CoNP spread into the cytosol and organelles. Consequently, massive amounts of Co ions and CoNP-rel can reach subcellular compartments normally unexposed to Co2+. This could explain the fact that the nuclear and mitochondrial Co concentrations resulted significantly higher than those obtained with Co2+. [ABSTRACT FROM AUTHOR]

Two new alkaloids, lycosprenine (1) and 2α-methoxy-6-O-methyllycorenine (2), along with 22 known alkaloids (3–23b), were isolated from the bulb of Lycoris sprengeri. Their structures were elucidated on the basis of spectral analysis and by comparison of the spectroscopic data with those of known compounds. Selected compounds (1–3 and 6–9) were tested for their neuroprotective activities against H2O2-, CoCl2- and Aβ25–35-induced SH-SY5Y cell injury, most of which exhibited neuroprotective effects of different degrees. [ABSTRACT FROM AUTHOR]

BaTi1−xCoxO3ceramics (x = 0.05∼0.25) have been synthesized with the solid state method and the Co-doping samples were formed hexagonal structure with x < 0.25. The XPS spectra show the two Co2+2p3/2and Co2+2p1/2peaks in full doping range, which indicates hexagonal BaTi1−xCoxO3are stable by Co2+, not Co3+-ion. Although the radius of Co2+-ion is larger than the radius of Ti4+-ion, the volume of unit cell is still decreasing with Co concentration increasing due to oxygen vacancy increasing, which can induce the hydrostatic pressure in this system. The Qxf value and K value are both decreasing with Co-doping level increasing due to hydrostatic pressure increasing. [ABSTRACT FROM PUBLISHER]

Hip replacement with large metal-on-metal (MoM) coupling has recently been under attention for its metal ions release, inducing several disorders. Since the blood level toxicity threshold for cobalt is known, the aim of this work is to determine whether Co serum and blood levels correlate with the synovial fluid level. Beside this, the synovial fluid Co from patients without prosthesis has also been measured. Co has been determined in 54 samples (32 unilateral MoM and 22 controls) with inductively coupled plasma mass spectrometry in the three matrices. In the prosthesized group, cobalt was significantly higher compared with controls and in the synovial fluid it strongly correlated with whole blood Co ( p = 0.847) and serum ( p = 0.855). Moreover, the Co levels into whole blood and serum were significantly different. In conclusion, haematic Co concentration correctly reflects Co local level. [ABSTRACT FROM AUTHOR]

A novel coordination polymer, namely {[Co3(HEIDC)2(4,4′-bipy)3]·2NO3·6H2O}n(1), has been hydrothermally successfully synthesized by the reaction of 2-ethyl-1H-imidazole-4,5-dicarboxylic acid (H3EIDC) with Co(NO3)2·6H2O in the presence of 4,4′-bipyridine (4,4′-bipy). The single-crystal structural study reveals that 1 is a 3D metal-organic framework, which can be viewed as made up of [Co3(HEIDC)2(4,4′-bipy)3]nunits, nitrate anions and solvent water molecules. Its thermal properties have been determined as well. [ABSTRACT FROM PUBLISHER]

Molecular dynamics simulation has been performed to explore the structure, thermodynamics and dynamics properties of Cu-Co melt based upon embedded atom method (EAM). The pair correlation function of liquid Cu50Co50show stronger interaction of homogeneous atom pairs. The coordination number (CN) of Cu-Cu and Co-Co in Cu50Co50melt is a little higher than that of Cu-Co at temperature of 1800 K. The calculated enthalpy of mixing is positive in the whole concentration range andSCC(q) increases sharply at lowerq, which are the typical features of dense fluid that exhibits phase segregation tendency. The interdiffusion coefficient shows same concentration dependence as that of demixing alloy. Our work indicates that Cu-Co melt exhibits weak demixing behaviour even at temperatures greater than those of bimodal curve. [ABSTRACT FROM AUTHOR]

The cobalt–based Fischer–Tropsch (F–T) catalysts, in which Co3O4nanocrystals, supported on TiO2nanotubes were prepared and charactered. The structure of the catalysts was characterized by X–ray diffraction, Transmission electron microscope and energy–dispersive X–ray spectroscopy. And the catalytic activity in F–T reaction was also investigated. In the CO hydrogenation reaction, the cobalt species dispersed on the TiO2nanotubes have higher selectivity and activity compare to sample in which Co3O4nanocrystals supported on TiO2bulk materials. According to the data of product selectivity, it can be concluded that cobalt–based F–T catalysts had higher selectivity and activity. [ABSTRACT FROM AUTHOR]

Treatment of cobalt(II) perchlorate hexahydrate with 2 M equiv. of 2-aminobenzenethiol (Habt) in acetonitrile afforded a tricationic tricobalt complex, [Co{Co(abt)3}2](ClO4)3·2CH3CN, by aerial oxidation. The molecular structure of the meso (ΔΛ) form of the complex was determined by X-ray crystallography. In the complex cation, the central Co is coordinated by six thiolate groups from two terminalfac(S)-[Co(abt)3] units in an octahedral geometry, forming a linear S-bridged tricobalt structure. [ABSTRACT FROM AUTHOR]

Silica gel H impregnated with microcrystalline cellulose gel in alkaline medium was used as a stationary phase for the thin layer chromatography of heavy metal cations. A mixture of 10% aqueous potassium thiocyanate and triton X-100 in 1:1 v/v has been identified as the best combination of mobile phase for achieving selective separation of cobalt from nickel. The efficacy of the chromatographic system has been investigated by monitoring reproducibility of RFvalues and spot compactness with respect to the change in sample concentration and matrix effect. The improved selectivity of impregnated silica gel H was expounded by SEM and FTIR studies. The typical surface modification as well as the chemical changes in impregnated silica gel H was attributed. Chromatograms of the cations were quantitatively evaluated by scanning densitometry in comparison with ICP elemental analysis. The proposed method is applied for the determination of cobalt and nickel cations in spiked samples of geological and industrial origin. [ABSTRACT FROM AUTHOR]

The reactions of freshly prepared solutions of [Co(CNC8H17-t)5](ClO4)2with three triarylphosphines, PR3(R = Ph, C6H4Me-p, C6H4OMe-p), were investigated in dichloromethane under pseudo-first-order conditions and with temperatures maintained at  ± 0.1 °C. Addition of each of the phosphines to the Co(II) complex solutions results in a shift in theλmaxof the electronic spectra accompanied by a change in color of the solution. The shift is attributed to ligand substitution. Analyses of the kinetic data suggest a general rate law given by: Rate =. Overall, the reactions of the cobalt(II) complex [Co(CNC8H17-0t)5]2+with the triarylphosphines are proposed to proceed via substitution/reduction mechanisms with final formation of disubstituted Co(I) complexes. The order of reactivity of the complex with the triarylphosphines was P(C6H4OMe-p)3 > P(C6H4Me-p)3 > PPh3. This order is explained in terms of the electron donating/π-acceptor properties of the phosphines. [ABSTRACT FROM AUTHOR]

A different proportion of Co, Bi doping NiCuZn ferrite was synthesised by the sol–gel self-propagating high temperature synthesis method. X-ray diffraction analysis showed that the sample grain density increases with the increase in doping amount of Bi ion. The hysteresis loop at T = 300 K of the samples showed that this ferrite is typical ferrimagnetic, coercive force Hc increases with the increase in doped ion and the saturation magnetisation increases firstly and then decreases with the increase in doped ion. Through Mössbauer spectrum analysis, the absorption area of A site is relatively reduced and the absorption area of B site is relatively increased with the compound doped increase. [ABSTRACT FROM AUTHOR]

Ferroelectric relaxor behavior of Ba0.92-xCa0.08Ndx(Zr0.18Ti0.815Y0.0025Mn0.0025)O3(x= 0, 0.5%, 1.0% and 2.0% mol) ceramics has been investigated. All the compositions have only tetragonal perovskite structure at room temperature. The dielectric peak constant of samples decrease and broaden, dielectric peak temperature (Tm) shifts toward lower temperature as the content of Nd increases. Diffuse phase transition (DPT) and strong frequency dispersion can be observed. When Nd varied from 0 to 2.0% mol, the degree of deviation from the Curie-Weiss law (△Tm) is from 62 to 108 and the parameterγfrom 1.588 to 1.853 respectively. The ferroelectric relaxor behavior is discussed using the random field model. [ABSTRACT FROM PUBLISHER]

Nanogenotoxicology is an emergent area of research, relevant for estimating the potential carcinogenic risk of nanomaterials. Since most of the approaches use in vitro studies, and neglecting the whole organism limits the accuracy of the obtained results, we have used Drosophila melanogaster to study the possible genotoxic potential of cobalt nanoparticles (Co NPs). The wing somatic mutation and recombination test has been the test of choice. This test is based on the principle that the loss of heterozygosis and the corresponding expression of the suitable recessive markers, multiple wing hairs and flare-3 can lead to the formation of mutant clone cells in growing up larvae, which are expressed as mutant spots on the wings of adult flies. Co NPs, as well as the ionic form cobalt chloride, were given to third instar larvae through the food, at concentrations ranging from 0.1 to 10 mM. The results obtained indicate that both cobalt forms are able to induce significant increases in the frequency of mutant clones. Although at low concentrations only Co NPs were genotoxic, the level of genetic damage obtained at the highest dose tested of cobalt chloride (10 mM) showed a significant higher increase in the frequency of total spots than those observed after the treatment with cobalt nanoparticles. As conclusion, our results indicate that Co NPs were able to induce genotoxic activity in the wing-spot assay of D. melanogaster, mainly via the induction of somatic recombination. The differences observed in the behaviour of the two selected cobalt forms may result from differences in the uptake. [ABSTRACT FROM AUTHOR]

Context. With regard to biological effects, the increasing number of early failure of metal-on-metal (MoM) hip arthroplasties and possible parenteral exposure to orthopedic metal alloys have caused concern for patients and providers alike. Objective. We sought to characterize our outpatient clinical experience of patients with MoM and other forms of hip implants and associated serum/blood chromium and cobalt levels, with a focus on possible systemic sequelae. Methods. This was an observational and retrospective chart review of consecutive patients presenting to two outpatient medical toxicology clinics from January 1, 2010-June 1, 2012 with history of hip implants. Presenting signs, symptoms, and interventions were reviewed. Available cobalt and chromium levels were summarized as median concentration with interquartile range. Results. A total of 39 patients were analyzed; of the 39 patients, 26 had MoM hip implants while 13 did not. Twelve patients exhibited no symptoms and nine sought evaluation for fatigue while two other patients had been previously diagnosed with fibromyalgia. Tinnitus/hearing loss was also a frequent complaint noted in 12 patients (one presenting complaint), however there was no difference between the incidence of this symptom between the MoM and non-MoM groups. Three patients were provisionally diagnosed with demyelinating neuropathy with one patient demonstrating marked (subjective and objective) improvement after revision. Patients with MoM arthroplasties generally exhibit an approximately tenfold increase in metal ion levels than traditional arthroplasties. Finally, 20 (51.2%) patients had replacement or revision of their hip implant with subsequent decreases in metal ion levels. Discussion. A majority of our patients had minor symptoms (fatigue and muscle aches) or no symptoms (n = 23 or 59%). Documented peripheral neurotoxicity is uncommon. The decision for hip revision solely for toxicologic reasons is rare and usually involves a multidisciplinary approach. Conclusion. Most patients seeking toxicologic referral may be minimally symptomatic and seek guidance regarding elevated blood or serum metal ions; however, solely toxicologic-based interventions are unusual. Revision was associated with a decrease in metal ion levels; however, subjective complaints did not correlate with metal ion levels. [ABSTRACT FROM AUTHOR]

Reactions of Co(ClO4)2·6H2O with 2-pyrazinephosphonic acid (2-paPO3H2) under two different hydrothermal conditions gave two new cobalt 2-pyrazinephosphonates, Co(2-paPO3H)2(1) and Co(2-paPO3)(H2O) (2). Compound1was obtained at 160 °C, while2was obtained at 180 °C. In1, two Co(II) units are bridged by two O–P–O’s into a dimer and the dimers are linked by pyrazinyl groups into a 1-D double chain. In2, the {CoO4N2} and {CPO3} polyhedra are interconnected via edge and corner-sharing into a metal phosphonate layer, and the layers are pillared by pyrazinyl groups into a 3-D network. Variable-temperature magnetic susceptibility studies reveal that both complexes have weak antiferromagnetic coupling between Co(II) ions. [ABSTRACT FROM AUTHOR]

A method utilizing size exclusion liquid chromatography (SEC) was developed to separate and quantify large molecular cobalt (Co) (e.g., albumin-Co) from cyanocobalamin (vitamin B12) and small molecular Co (e.g., glutathione-Co and free Co) in human serum. Highly selective and sensitive detection using inductively coupled plasma–mass spectrometry was coupled with SEC to provide a method with reliable accuracy, precision, recoveries, stability, and a detection limit of 0.037 μg/L in undiluted serum. Other divalent metal cations known to compete with Co(II) for serum albumin-binding sites (such as iron, zinc, manganese, cadmium, copper, nickel, and lead) did not significantly alter Co(II) quantification. Co–protein binding capacity determination of individual serum samples indicated that addition of 2500 μg Co/L to undiluted human serum resulted in approximately 90% distribution to the large molecular Co peak, consistent with Co binding to high-affinity divalent metal binding sites on albumin. Since serum albumin binding partially sequesters biologically active Co(II) ions, this method provides an important tool for better understanding the kinetics and toxicology of Co compounds. Thus, the proposed method might play an important role in establishing Co dose–response relationships that affect the equilibrium concentrations of free ionic Co(II). [ABSTRACT FROM PUBLISHER]

A new analytical method for determining cobalt (Co) species in human serum by size exclusion chromatography with inductively coupled plasma mass spectrometry (SEC-ICP-MS) was applied to serum samples collected from 12 human volunteers who participated in a Co(II) chloride supplement study involving ingestion of 1 mg Co/day for up to 90 consecutive days. The study protocol included determination of serum total Co by acid digestion followed by ICP-MS. Co speciation assay measurements were conducted for up to 13 time points per individual spanning from one to two weeks before dosing began to two weeks after dosing ceased. The Co speciation assay showed good recovery >91% relative to total Co measurements. Undiluted serum demonstrated uniform fractions of large molecular Co defined as Co bound to albumin and other proteins >50 kDa at 96% and the residual as small molecular Co defined as free Co(II) and <1 kDa Co-complexes for individual serum Co concentrations up to 146 μg/L. There were no dose-related changes in Co distribution. Analysis of the same serum samples with tenfold dilution in 0.1 M acetic acid led to a lower fraction of large molecular Co at 87%, with the difference between diluted and undiluted measurements being 8.4%. The difference noted between undiluted and diluted large molecular Co may be attributed to Co release from albumin. Data demonstrated that large molecular Co was the predominant Co species in both undiluted and diluted human serum over a broad range ofin vivoCo concentrations, reflecting high albumin–Co binding capacity. These data validate the Co speciation assay and may be employed in understanding further the toxicokinetics and dose-response relationships for Co species. [ABSTRACT FROM PUBLISHER]

The influence of the grain boundary (GB) specific areasGBon the appearance of ferromagnetism in Co-doped ZnO has been analysed based on a review of numerous research contributions from the literature on the origin of the ferromagnetic behaviour of Co-doped ZnO. An empirical correlation has been found that the value of the specific grain boundary areasGBis the main factor controlling such behaviour. The Co-doped ZnO becomes ferromagnetic only if it contains enough GBs, i.e., ifsGBis higher than a certain threshold valuesth = 1.5 × 106 m2/m3. It corresponds to the effective grain size of about 1 µm assuming a full dense material and equiaxial grains. The magnetic properties of Co-doped (0 to 42 at. %) ZnO dense nanograined thin films have been investigated. The films were deposited using the wet chemistry “liquid ceramics” method. The samples demonstrate ferromagnetic behaviour withJsup to 0.12 emu/g and coercivityHc ∼ 0.01 T. Saturation magnetization non-monotonically depends on the Co concentration. The dependence on Co content can be explained by the changes in the structure of a ferromagnetic “grain boundary foam” responsible for the magnetic properties of pure and doped ZnO. [ABSTRACT FROM PUBLISHER]

An effective spherical interaction potential for HeCO+and values for the momentum-transfer collision integral are obtained from experimental ion mobility data by using the direct inversion method. The potential is fitted to a Morse–Spline–van der Waals (MSV) model potential. Consistency is checked by calculating collision integrals and the mobilities of CO+ions in He gas from the MSV potential and showing that they agree with the experimental data. The separation- and angle-dependent interaction potential energy surface is calculated from the spin-unrestricted, fourth-order Moller–Ploesset theory with single, double, triple and quadruple excitations, using a 6-311++G(3df,3pd) basis set while correcting for basis set superposition error. Full and partial versions of theab initiopotentials are used to determine the transport cross-sections for the collisions of CO+with He as a function of the collision energy at fixed angles between the C–O bond axis and the internuclear axis. Finally, the transport coefficients of CO+ions moving through He are calculated accurately, over a wide range of reduced electric field and gas temperature, using an extension of the Monchick–Mason approximation. [ABSTRACT FROM PUBLISHER]

The separation of Co(II) from Ni(II) in a sulfate solution across a hollow fiber membrane containing the sodium salt of Cyanex 302 dissolved in kerosene was studied. The Co(II) was simultaneously re-extracted into a strip phase containing H2SO4in another hollow fiber membrane. Experiments were conducted to determine the effects of the feed pH (4.5–5.5), carrier concentration (0.1–0.4 mol/dm3), strip acidity (0.1–2 mol/dm3), and flow rates of the three phases (200 ∼ 600 cm3/min). The percent of each metal ion extracted was found to increase with increasing feed pH, Na-Cyanex 302 concentration, and feed flow rate in the extraction module. Na-Cyanex 302 extracted Co(II) preferentially over Ni(II) under identical extraction conditions. Increasing the strip acidity and strip phase flow rate increased the recovery of Co(II) by the re-extraction module. The effect of the flow rate of the organic phase on the percent extraction and re-extraction of Co(II) were negligible. The separation of Co(II) from Ni(II) in sulfate solution was achieved using 0.3 mol/dm3Na-Cyanex 302 as extractant and 2 mol/dm3H2SO4as stripping solution in HFMCs during a 2 h extraction. At a feed pH of 5, the percent extraction and recovery of Co(II) were 84.6% and 43.7% (Ni/Co < 0.05 in strip phase), respectively. The extraction efficiency and recovery of Co(II) using one-stage HFMC experiments were better than those using two-stage HFMC experiments. [ABSTRACT FROM PUBLISHER]