High Cobalt Research Articles

Genetic analysis of oxidative and endoplasmic reticulum stress responses induced by cobalt toxicity in budding yeast

BackgroundCobalt is an important metal cofactor of many living cells. However, excessive cobalt is toxic and can cause cell death and even several diseases in humans. Saccharomyces cerevisiae is a useful tool for studying metal homeostasis and many of the genes and pathways are highly conserved in higher eukaryotes including humans. MethodsThe intracellular cobalt and reactive oxygen species (ROS) levels were measured by an atomic absorption spectrometer and DHE staining method, respectively. The expression of genes involved in scavenging oxidative stress was tested by qPCR method, while the expression of UPRE-lacZ report gene was analyzed via β-galactosidase activity assay. ResultsUsing a genome-scale genetic screen, 153 cobalt-sensitive and 37 cobalt-tolerant gene deletion mutants were identified from Saccharomyces cerevisiae. We showed that 101 of the cobalt-sensitive mutants accumulated higher intracellular cobalt compared to wild-type. The intracellular ROS levels in 112 of the mutants were induced by cobalt, which might be caused by the decreased expression of genes involved in scavenging oxidative stress in response to cobalt. Moreover, more than one-third of the cobalt-sensitive mutants were also sensitive to tunicamycin, and cobalt stress might induce the unfolded protein response (UPR) through serine/threonine kinase and endoribonuclease Ire1. ConclusionsThis study reinforced the fact that cobalt toxicity might be due to the high intracellular cobalt and ROS levels, and the endoplasmic reticulum stress responses induced by cobalt. General significanceElucidating the toxicity mechanisms of cobalt stress response will help reveal new routes for the treatment of the diseases induced by cobalt.

CONDITIONS OF MICROELEMENTS EXCHANGE PROCESSES IN WOMEN’S PLACENTS IN INTRAUTERINE INFECTION OF THE FETUS

The aim:to study the content of trace elements (Fe, Cu, Zn, Co, Cr, Ni, Pb) in the placenta of pregnant healthy women and with signs of intrauterine infection of the fetus, features of transplacental transmission of infectious process from mother to fetus and to investigate the role of the placenta in trace element supply of the fetus. Materials and methods. 43 pregnant women between the aged 16 to 40 years were monitored, including 12 with physiological pregnancy (group 1) and 31 with signs of STI (group 2). All pregnant women underwent standard comprehensive examination, evaluation of fetal cardiac output and non-stress testing using cardio-toсography (CTG) in the third trimester. The group of pregnant women with signs of fetal ulcers included women whose pregnancy was complicated by chronic fetoplacental dysfunction (FPD), infectious lesions of the fetoplacental complex, which were diagnosed on the basis of ultrasound signs of placenta, syndrome of infectious and surrounding infections. Results:The content of essential trace elements in the placenta of the main group was significantly lower than in the placenta of the control group. There was a decrease in the concentration of iron by 32%, zinc - by 46%, nickel - by 44%, copper more than tripled, chromium - 4 times. Deficiency of essential trace elements (iron, zinc, copper, chromium, nickel) and elevated lead content in the placenta leads to the formation of conditions for the development of placental dysfunction, the progression of which leads to fetal distress, developmental delay syndrome and antenatal fetal death. Conclusions:1. One of the links in the pathogenesis of intrauterine infection in the fetus is the imbalance of essential trace elements in the system «mother - placenta - fetus». 2. Pregnant women with signs of intrauterine infection are characterized by a deficiency of serum Fe, Cu, Zn, Ni and an increased content of Pb, Cr and Co compared with pregnant women with physiological pregnancy. 3. Umbilical cord blood of women with evidence of fetal fetal infection also has a reduced content of iron, copper, zinc and high levels of lead, cobalt and chromium. 4. Disruption of placental function in intrauterine infection of the fetus is caused by reduced content of iron, zinc, copper, nickel and lead accumulation.

Uptake, translocation and accumulation of nickel and cobalt in Berkheya coddii, a 'metal crop' from South Africa.

Hyperaccumulator plants have the ability to efficiently concentrate metallic elements, e.g. nickel, from low-grade sources into their living biomass. Although the majority of nickel hyperaccumulator plant species restrict cobalt uptake, some species are able to co-accumulate cobalt when growing in ultramafic soils. The asteraceous perennial herb Berkheya coddii from South Africa is one of the most promising agromining crops known globally. It may accumulate nickel in excess of 30 000 μg g-1 in dry leaves, while co-accumulating up to 600 μg g-1 cobalt. This study aimed to elucidate the interactions between nickel and cobalt for uptake by and translocation into B. coddii through a pot experiment including various cobalt/nickel treatment combinations in soil, after which uptake and localisation were recorded. Cobalt in the substrate limits nickel uptake by B. coddii plants and is mainly retained in the basal leaves in contrast to Ni that is rapidly transferred to the top of the plant. B. coddii was more tolerant to high Ni concentration, whether in the substrate or internally but remains a promising crop which could be used, with suitable agronomic measures and practices, for cobalt agromining in areas with high soil cobalt but low soil nickel. A yield of 77 kg ha-1 nickel and 16.5 kg ha-1 cobalt may be attainable under optimum conditions.

Binuclear iminopyridine-bridged 3d late transition metal complexes with o-semiquinones

Four novel binuclear high spin manganese(II), iron(II), cobalt(II) and nickel(II) complexes containing 1,2-bis(pyridin-2-ylmethylene)-para-phenylenediamine as a bridging ligand have been synthesized and investigated. Molecular structures of manganese and cobalt complexes were established by single crystal X-ray structural analysis. For all the complexes the magnetic susceptibility measurements have been performed. According to the obtained magnetic data the energies of intramolecular magnetic exchange interactions strongly depend on the electron structure of metal ion. In addition, all the obtained complexes demonstrate very weak antiferromagnetic metal-metal interaction.

Revealing the activation effects of high valence cobalt in CoMoO4 towards highly reversible conversion

Molybdenum (Mo)-based transition metal oxides normally delivery superior energy density in lithium ion batteries through electrochemical conversion reactions. The main challenge for this kind of electrode material is to promote reversible transformation of Li2O and alleviate the volume expansion during lithiation/delithiation processes. Here, electrochemical reaction mechanism of CoMoO4 investigated by in-situ X-ray diffraction and ex-situ Transmission electron microscopy reveals the irreversible transformation from CoMoO4 to CoO and MoO3 in the first cycle. During subsequent charge/discharge process, high valence state cobalt ions originated from Co2+ provide additional capacity and promote the electrochemical reversible reaction between MoO3 and Li2O, thus facilitating the release of irreversible capacity. Benefited by the contributor of high valence state cobalt ion, when CoMoO4 was utilized as Li-storage anode, high reversible capacity (1585.5 mAh g−1 at 200 mA h−1 after 150 cycles) and excellent cyclic stability (~100% retention after 400 cycles at 1000 mA g−1) are delivered. Such an optimized anode material expands the potential to develop lithium-ion batteries with significantly higher energy density.

Cobalt Chalcogenides/Cobalt Phosphides/Cobaltates with Hierarchical Nanostructures for Anode Materials of Lithium-Ion Batteries: Improving the Lithiation Environment.

Lithium-ion batteries (LIBs) are widely used in electric vehicles and portable electronic devices due to their high energy density, long cycle life, environmental friendliness, and negligible memory effect, though they also suffer from low power density, safety issues, and an aging effect. Cobalt chalcogenides/phosphides as promising anode materials have attracted intensive interests due to their high theoretical capacity based on the conversion mechanism. Cobaltates (XCo2 O4 , X = the other metal) have attracted attention because the X element can partially replace the high cost and toxic cobalt element. The serious volume variation during the cycling process has an impact, however, on the lithiation environment of above materials. Hierarchical construction can provide more active sites and shorten the diffusion pathways of Li ions as well as accommodating the volume expansion during lithiation processes. Herein, the research progress on the synthesis methods, structural characteristics, and electrochemical performances of cobalt chalcogenides/cobalt phosphides/cobaltates with hierarchical nanostructures for LIBs is presented. The concluding remarks highlight the research challenges and possible development directions of cobalt chalcogenides/cobalt phosphides/cobaltates with tailored hierarchical nanostructures for LIBs.

Novel application of CoAl-layered double hydroxide/reduced graphene oxide nanocomposite as a highly efficient cathode additive for nickel-based secondary batteries

A series of Co–Al layered double hydroxide (Co–Al LDHs)@reduced graphene oxide (rGO) nanocomposite are successfully synthesized through a hydrothermal method and applied as novel cathode additives for nickel-based secondary batteries for the first time. The obtained Co–Al LDHs@rGO nanocomposite is composed of many thin nanosheets, displaying laminated structure. The effects of various Co–Al LDHs@rGO on the properties of nickel cathodes were compared and its action mechanism was further investigated. Interestingly, the Ni(OH)2 electrode added with Co–Al LDHs@rGO(10%) delivers best high-rate performances and more stable cycling stability as comparison with the pure Ni(OH)2 and Ni(OH)2+CoO electrodes. Owing to its soft and flexible structure, Co–Al LDHs@rGO(10%) is conducive to modify the electronic conductivity, proton diffusion and electrochemical reversibility of the electrode by forming a more effective and stable conductive network. Especially, Co–Al LDHs@rGO(10%) with high electrochemical activity can contribute much higher discharge capacity than the commercial CoO. Owing to its high efficiency and low cobalt content, Co–Al LDHs@rGO(10%) can be applied as an effective, cheap, and promising cathode additive for nickel-based rechargeable batteries.

Structure and magnetic properties of melt-spun ribbons of Sm(Co,Fe,Cu,Zr)z with high cobalt content

In this work the investigation of structure and magnetic properties of SmCo7.5Fe3.09Cu0.84Zr0.3 and SmCo7.52Fe3.01Cu0.84Zr0.28 melt-spun ribbons with high cobalt content after different heat treatments was performed. The phase composition and magnetic properties of the samples were determined. Isothermal aging at 600-800 °C with subsequent slow cooling leads to the slight increase in coercivity of the samples. After arc-melting the phase composition of the samples is hexagonal Sm2Co17 and CoFe. After melt-spinning a small amount of the disordered SmCo7 phase is detected. After aging metastable SmCo7 disappears, and the phase structure is basically hexagonal phase Sm2Co17 and CoFe, except a tiny amount of SmCo5 and rhombohedral Sm2Co17 after aging at 800 °C. Magnetic properties of the samples are relatively low because the phases, essential for the high-coercive state in these alloys, do not form during applied heat treatments.

Feasibility analysis of 60Co production in pressurized water reactors

The radioactive isotope 60Co is used in many applications and is typically produced in heavy water reactors. As most of the commercial reactors in operation are pressurized light water reactors (PWRs), the world supply of high level radioactive cobalt would be greatly increased if 60Co could be produced in them. Currently, 60Co production in PWRs has not been extensively studied; for the 59Co (n, γ) 60Co reaction, the positioning of 59Co rods in the reactor determines the rate of production. This article primarily uses the models of 60Co production in Canadian CANDU power reactors and American boiling water reactors; based on relevant data from the pressurized water Daya Bay nuclear power plant, a PWR core model is constructed with the Monte Carlo N-Particle Transport Code; this model suggests changes to existing fuel assemblies to enhance 60Co production. In addition, the plug rods are replaced with 59Co rods in the improved fuel assemblies in the simulation model to calculate critical parameters including the effective multiplication factor, neutron flux density, and distribution of energy deposition. By considering different numbers of 59Co rods, the simulation indicates that different layout schemes have different impact levels, but the impact is not large. As a whole, the components with four 59Co rods have a small impact, and the parameters of the reactor remain almost unchanged when four 59Co rods replace the secondary neutron source. Therefore, in theory, the use of a PWR to produce 60Co is feasible.

Influence of cryo-processing on properties of tungsten carbide with low, medium and high cobalt content

This research was designed to evaluate the influence of cryo-processing on properties of tungsten carbide with varied cobalt content. Samples of uncoated tungsten carbide with 6% (WC-6 wt%Co), 9% (WC-9 wt%Co) and 25% cobalt (WC-25 wt%Co) content were fabricated for the research. Magnetic properties, porosity analysis, eta phase analysis by microscopic observation, EDS, XRD and Vickers hardness were evaluated. Investigation shows that 25% cobalt content samples after cryo-processing exhibit a significant improvement of around 2.2% in Vickers hardness and 8.7% in coercivity followed by samples with 9% cobalt grade (1.2% increase in Vickers hardness and 2.1% in coercivity), whereas 6% cobalt samples showed negligible changes. There is no change in the other properties in any of the selected grades. The change in Vickers hardness and coercivity are attributed to the cobalt’s phase transformation from FCC to HCP structure in cryo-processed samples. This study reveals that the amount of cobalt used in the fabrication of tungsten carbide tools is the determinant factor for the changes in properties.

Microporous core-shell Co11(HPO3)8(OH)6/Co11(PO3)8O6 nanowires for highly efficient electrocatalytic oxygen evolution reaction

Exploring high-efficient oxygen evolution reaction (OER) catalysts is critical for producing clean H2 fuel through water splitting. Co and P involved Co-Pi and cobalt phosphide OER catalysts attracted tremendous attention, while limited report on cobalt phosphite as an OER catalyst. Herein, a novel cobalt phosphite nanowires with microporous 1D channel have been succsessfully discovered with remarkable catalytic performance of a low overpotential of ˜340 mV and Tafel slope of 60 mV dec−1 at 10 mA cm−2 at pH 14. Through comprehensive structural characterization, the effective species has been clearly illustrated to be the in-situ formed heterostructural Co11(HPO3)8(OH)6/Co11(PO3)8O6 core-shell structure nanowires. This work fills the gap for exploring high efficient cobalt phosphites OER catalysts under akaline condition and paves the way for exploring novel high efficiency waster splitting catalysts.

Characterization of cobalt oxide nanoparticles produced by laser ablation method: Effects of laser fluence

Abstract The role of laser fluence in producing cobalt oxide nanoparticles in distilled water by laser ablation method has been studied experimentally. Output of a pulsed Nd:YAG laser of 1064 nm wavelength and 7 ns pulse width with 10 Hz repetition rate was employed to irradiate a high purity cobalt bulk in distilled water. According to results, size of produced nanostructures as well as their oxidation was strongly under the influence of laser energy. Although a high purity Co bulk was used as the target of laser irradiation in the experiment but produced nanoparticles were mainly cobalt oxides. X ray diffraction pattern indicates that produced nanostructures are Co3O4. The excitonic absorption peak of Co3O4 nanoparticles was occurred in UV region. Results show that with increasing the fluence of laser pulse, size of nanoparticles was decreased while their aggregation was increased noticeably.

A robust and precious metal-free high performance cobalt Fischer–Tropsch catalyst

Slurry-phase Fischer–Tropsch catalysis is widely used in the production of synthetic transportation fuels, but places severe stresses on the catalyst due to the demanding hydrothermal and mechanical reaction conditions. In this Article we report the synthesis, characterization and catalytic performance of a robust cobalt-based Fischer–Tropsch catalyst. Combining an inert alpha alumina support with an appropriate cobalt addition method produces a material that is easy to reduce without precious metal additives and is mechanically and hydrothermally stable. Unlike many Fischer–Tropsch catalysts, this material is resistant to sintering and shows excellent selectivity and good activity in slurry-phase testing over 1,000 hours. The Fischer–Tropsch reaction is one of the key means of producing synthetic fuels. Here a deposition method to disperse cobalt nanoparticles across an alpha alumina support is shown to produce a highly stable system capable of withstanding demanding conditions while providing excellent activity.

Realizing High Voltage Lithium Cobalt Oxide in Lithium-Ion Batteries

The combination of high voltage cathode and metal or graphite anodes provides a feasible way for future high-energy batteries. Among various battery cathodes, lithium cobalt oxide is outstanding for its excellent cycling performance, high specific capacity, and high working voltage and has achieved great success in the field of consumer electronics in the past decades. Recently, demands for smarter, lighter, and longer standby-time electronic devices have pushed lithium cobalt oxide-based batteries to their limits. To obtain high voltage batteries, various methods have been adopted to lift the cutoff voltage of the batteries above 4.45 V (vs Li/Li+). This review summarizes the mechanism of capacity decay of lithium cobalt oxide during cycling. Various modifications to achieve high voltage lithium cobalt oxide, including coating and doping, are also presented. We also extend the discussion of popular modification methods for electrolytes including electrolyte additives, quasi-solid electrolytes, and electr...

Content of macronutrients in oat (Avena sativa L.) after remediation of soil polluted with cobalt

The purpose of this study was to determine the remediation effect of various substances (manure, clay, charcoal, zeolite and calcium oxide) on limiting the influence of high cobalt doses (0, 20, 40, 80, 160 and 320 mg/kg of soil) on the content of macroelements in grain, straw and roots of oat. The doses of cobalt applied in this experiment as well as soil amendments such as manure, clay, charcoal, zeolite and calcium oxide had a significant effect on the content of the analysed macronutrients in grain, straw and roots of oat. In the series without any neutralising substances, the soil contamination with cobalt caused an increase in the content of nitrogen, phosphorus, sodium, calcium and, partly, potassium, in grain, straw and roots of oat. Among the neutralising substances tested, the most unambiguous effect was produced by manure, which raised the content of all macronutrients (except calcium and magnesium) in oat grain, straw and roots. The influence of the other substances on the content of macronutrients in oat plants was less equivocal. However, all of them, especially calcium oxide, tended to induce a decrease in the content of most macronutrients in grain, straw and roots of oat.

Evolution of cobalt species in glow discharge plasma prepared CoRu/SiO2 catalysts with enhanced Fischer-Tropsch synthesis performance

Glow discharge plasma was applied to substitute thermal calcination during catalyst preparation. Evolution of cobalt particles in cobalt-ruthenium based catalysts at different stages (fresh prepared, reduced, after Fischer-Tropsch synthesis (FTS) reaction) were studied using a series of characterization techniques. Glow discharge plasma can be developed as an efficient technique to decompose metal salt. Cobalt dispersion was greatly enhanced by glow discharge plasma treatment, and higher initial cobalt dispersion was found on the one with lower treating intensity. However, cobalt crystallites generated by plasma treatment below certain intensity had poor thermal stability, they were tended to aggregate into large particles during reduction and reaction processes, and thus severe deactivations were observed during FTS tests. Besides cobalt sintering, mass transfer limitation at high FTS activity due to the pore plugging by long-chain hydrocarbons was also one of the important reasons for deactivation. The CRS-P140 catalyst with higher plasma treating intensity combined relatively high cobalt dispersion, high cobalt reducibility and relatively stable cobalt distribution during reduction or reaction, showed a high FTS activity with less activity loss.

Structure, Linear Thermal Expansion Coefficient, and Electrical Conductivity of Y0.9Ca0.1Cr1 – уCoуO3 (у = 0–0.9) Perovskites

The structure, thermal expansion coefficient, and electrical conductivity of Y0.9Ca0.1Cr1 – уCoуO3 (у = 0–0.9) compounds with the perovskite structure have been investigated in air in the temperature range of 100–1000°С. The linear thermal expansion coefficient of Y1 – хCaхCr1 – уCoуO3 lies in the range of (8.77–16.1) × 10–6 K–1. The maximum electrical conductivity is attained for the Y0.9Ca0.1Cr0.6Co0.4O3 composition. It is shown that the electrical conductivity at low (25–270°С) temperatures and weak substitution of cobalt for chromium is mainly due to the hopping of one electron hole from Cr4+ to Cr3+. At high (565–1000°С) temperatures and cobalt contents, this conductivity mechanism is supplemented with the conductivity caused by the hopping of an electron hole from Cо3+ to Cо2+.

The effect of cobalt content in Zn/Co-ZIF-8 on iodine capping properties

We have tested for iodine sorption properties a variety of samples with ZIF-8 structure and various Zn/Co ratios (100/0, 95/5, 75/25, 50/50 and 0/100 in mol%). For iodine saturation, an excess of sublimated iodine crystals was used. We have observed that the prevailing trend for all compositions is adsorption of most of the iodine molecules by the internal surface and retaining them up to framework collapse. However, Co-doping results in a small decrease in the thermal stability of the samples after iodine saturation. Moreover, in the samples with high cobalt content, the part of iodine adsorbed by the external surface is higher than in zinc analogs. Combination of TGA and FTIR data evaluated the impact of lower flexibility of Co-linker bonds on the transfer of iodine molecules from the external surface of the crystals to internal pores.

Super-Hydrophobic Co–Ni Coating with High Abrasion Resistance Prepared by Electrodeposition

Although super-hydrophobic surfaces have great application prospects in industry, their preparation cost and mechanical durability have limited their practical utilization. In this work, we presented a new low-cost process preparation for super-hydrophobic Co–Ni coating on carbon steel substrate via an electrodeposition route. The deposited Co–Ni coating with cauliflower-shaped micro-nano structures exhibited high super-hydrophobic properties with water contact angles over 161° after modification with 1H,1H,2H,2H-Perfluorooctyltrichlorosilane (PFTEOS). Evaluated by the linear abrasion methods, the super-hydrophobic coating can maintain super-hydrophobicity after abrasion distance of 12 m under the applied pressure of 5 kPa, which was attributed to the high cobalt content of the Co–Ni coating. Moreover, electrochemical tests showed that the super-hydrophobic Co–Ni coatings exhibited a good anti-corrosion performance thus providing an adequate protection to the carbon steel substrates.

Relating to the rational utilization of manganese-containing raw materials

Data on main manganese ores deposits by Russian Federation subjects presented. It was shown, that main part of manganese ore raw materials prognostic resources are concentrated in Altaj-Sayan and Enisej-East-Sayan metallogenic provinces. Estimation of metallurgical value of manganese ores deposits, located at the territory of Altaj-Sayan metallogenic province, carried out. A technological flow-chart of manganese-containing raw materials elaborated, comprising high quality manganese concentrate obtaining, its preparation, synthesis of marokite and mono-phase CaMnO3 material, marokite briquetting with a reducing agent and application for steel processing in ladle-furnace facility. A possibility shown to utilization of CaMnO3 mono-phase material mixed with a reducing agent and high quality manganese concentrate for production of metal manganese. Thermodynamic calculations and experiment studies on polymetallic manganese-containing raw material beneficiation enabled to determine main technological parameters of extraction and elaborate a technological flow-chart of beneficiation. The elaborated technology enables to obtain high quality manganese, nickel, iron and cobalt concentrates. Application of optimal technological parameters of beneficiation enables to extract from a polymetallic manganese-containing raw materials up to 95–97% of manganese, 98–99% of nickel, 96–98% of iron. It was shown, that it is reasonable to use the manganese concentrate for low phosphor metal manganese smelting, that will enable to decrease the dependence from manganese-containing materials import. A technology of steel alloying by obtained nickel concentrate elaborated. The substitution of metal nickel by nickel concentrate will considerably reduce expenses for alloying. A technology of metalized iron production by a solid-phase reducing method from an iron concentrate also elaborated, which will enable to decrease impurities content in steel during its application.