Cobalt (Total 43418 Papers Found)

Cobalt (43418 Papers Found)
BACKGROUND Cobalt oxide nanoparticles (Co(3)O(4)NPs) are increasingly recognized for their utility in biological applications, magnetic resonance imaging, and drug delivery. However, little is known about the toxicity of Co(3)O(4)NPs in human cells. METHODS We investigated the possible mechanisms of genotoxicity induced by Co(3)O(4)NPs in human hepatocarcinoma (HepG2) cells. Cell viability, reactive oxygen species (ROS), glutathione, thiobarbituric acid reactive substance, apoptosis, and DNA d ...
Heme is present in all cells, acting as a cofactor in essential metabolic pathways such as respiration and photosynthesis. Moreover, both heme and its degradation products, CO, iron and biliverdin, have been ascribed important signaling roles. However, limited knowledge is available on the intracellular pathways involved in the flux of heme between different cell compartments. The cattle tick Boophilus microplus ingests 100 times its own mass in blood. The digest cells of the midgut endocytose b ...
An NADH: (acceptor) oxidoreductase from the cytosol of soybean root nodules was purified by ammonium sulfate fractionation, hydroxylapatite adsorption, and Sephacryl S-200 Superfine chromatography. The native molecular weight of the reductase was found to be 100,000 by analytical gel filtration and 83,000 by equilibrium ultracentrifugation. The subunit molecular weight was 54,000 as determined by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis. The pI of the enzyme was 5.5. With f ...
Heavy metal and trace element concentrations were examined in topsoils to evaluate a cement plant and an industrial waste incinerator as pollution sources. As, Ba, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Rb, Sb, Sc, Se, Sm, Ta, Tb, Th, U, Yb and Zn were measured by Neutron Activation Analysis (NAA), and Co, Cu, Fe, Ni, Pb and Zn by a 0.5M-hydrochloric extraction technique using an Atomic Absorption Spectrophotometer (AAS). The Cr total concentration and HCl-extracted Co and Mn were po ...
A SERIES of sediment samples from the TAG Hydrothermal Field1 have been collected and analysed for transition metals, and for uranium and thorium isotopes. We show here that metal enrichment of sediment samples is ubiquitous, but geographically variable. Non-detrital metal accumulation rates in one core are Fe and Mn 15.0 and 0.7 mg cm−2 10−3 yr; and Ni, 180; Co, 93; Cu, 134; and Cr, 148 µg cm−2 10−3yr. The hydrothermal field is located on the eastern wall of the Mid-Atlantic Ridge Rift ...
The influence of different functionalization treatments of the support on the electrocatalytic activity towards CO and methanol oxidation at platinum nanoparticles deposited on ordered mesoporous carbons (OMC) has been studied for the first time. Before deposition of the metal, the carbon support was functionalized applying several procedures, with the purpose to generate oxygenated groups for anchoring the Pt nanoparticles by the formic acid (FM) and borohydride (BM) reduction methods. Good dis ...
The effects of cholesterol and adrenodoxin binding on resonance Raman spectra of cytochrome P-450scc in both oxidized and CO-reduced states were examined. Upon cholesterol binding, oxidized cytochrome P-450scc showed a significant shift of spin equilibrium from low-spin to high-spin state. Addition of adrenodoxin caused a complete conversion of cholesterol-bound oxidized cytochrome P-450scc to a pure high-spin state that was considered to be in the hexacoordinated state judged by the v10 mode at ...
Recent work has suggested that the chromosomally encoded TetA(L) transporter of Bacillus subtilis, for which no physiological function had been shown earlier, not only confers resistance to low concentrations of tetracycline but is also a multifunctional antiporter protein that has dominant roles in both Na(+)- and K(+)-dependent pH homeostasis and in Na+ resistance during growth at alkaline pH. To rigorously test this hypothesis, TetA(L) has been purified with a hexahistidine tag at its C termi ...
BACKGROUND Proton therapy can deliver a more conformal dose distribution than photon radiation and may allow safe dose escalation in stage III lung cancer. Early outcomes are presented here for patients who received proton therapy with concurrent chemotherapy for non-small-cell lung cancer (NSCLC). MATERIALS AND METHODS Nineteen patients with regionally advanced NSCLC were treated with concurrent chemotherapy (carboplatin and paclitaxel [n = 18]) and proton therapy from August 2008 to April 20 ...
BACKGROUND Hard-on-hard bearings for total hip arthroplasty continue to warrant analysis even though crosslinked polyethylene is performing very well. Ceramic-on-metal (CoM) has low in vitro wear and did well in an early clinical trial. We report on a prospective, randomized, multicenter investigational device trial comparing CoM with metal-on-metal (MoM). QUESTIONS/PURPOSES (1) Is there a difference in the number or type of revisions comparing CoM with MoM? (2) Are cobalt and chromium metal l ...
A cofacial iron tetraphenyl porphyrin dimer, , bio-inspired by the Ni-Fe containing metalloenzyme, carbon monoxide dehydrogenase (CODH), efficiently and selectively catalyses the electrochemical reduction of CO2 to CO in DMF/10% H2O solution at the electro-generated Fe(0)(por) species with high Faradic efficiency (95%) and TOF (4300 s(-1)) at a moderate overpotential, η = 0.66 V. ...
Citation Datta, Soumendu et al. " Engineering the magnetic properties of the Mn_{13} cluster by doping. " Physical Review B 83 (2011). Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. With a goal to produce a giant magnetic moment in a Mn 13 cluster that will be usef ...
Adducts of hydrogen peroxide and transition metals have been implicated as intermediates in biological and industrial processes but have only recently been observed. Therefore, knowledge of how hydrogen peroxide interacts with transition metals is extremely limited. Herein, we report the synthesis of H2O2 complexes of cobalt, nickel, and copper supported by sulfonamido ligands with second-sphere hydrogen bonding. Binding constant and decay kinetics are reported for four new M(H2O2) adducts, prov ...
Coalpha-[alpha-(Aden-9-yl)]-Cobeta-adenosylcobamide (pseudocoenzyme B12) purified from Clostridium tetanomorphum has been reacted with ribonucleotide reductase purified from Lactobacillus leichmannii under various conditions, and the properties of the products obtained have been compared by electron paramagnetic resonance (EPR) with those previously reported for products formed from the normal coenzyme (adenosylcobalamin). The rapidly formed intermediate and the slowly formed "doublet" species f ...
Pure rotational spectra of the ground vibrational states of six isotopologues of OC···AgI have been measured by chirped-pulse Fourier transform microwave spectroscopy. The spectra are assigned to determine the rotational constant, B(0), centrifugal distortion constant, D(J), and nuclear quadrupole coupling constant of the iodine atom, χ(aa)(I). The complex is linear. Isotopic substitutions at the silver, carbon, and oxygen atoms allow bond lengths to be established by the r(0), r(s), and r(m ...
The novel phase Na2-xCo6(OH)3[HPO4][Hx/3PO4]3 (x≈ 1.1) was prepared by hydrothermal synthesis at 553 K. Its crystal structure was determined using single-crystal X-ray diffraction data and refined against F(2) to R = 0.052, including positions of all hydrogen atoms. The compound crystallizes in the hexagonal space group P63mc, with unit-cell parameters a = 12.630(3) Å, c = 5.017(1) Å, V = 693.1(3) Å(3), and Z = 2. The crystal structure is based on a 3D framework built from CoO6 octahedra an ...
In this paper, a series of Cu-Fe-Ti and Co-Fe-Ti oxide catalysts were prepared by sol gel method. Cu-Fe-Ti and Co-Fe-Ti oxide catalysts showed the moderate catalytic activity for selective catalytic reduction (SCR) of NO with NH3 at low temperature. The catalysts with the molar ratio as 4:1:10 (M:Fe:Ti) were selected as the representatives for comparison of reaction properties and H2O resistance, which were denoted as Cu-Fe/TiO2 and Co-Fe/TiO2 respectively. The characterization results manifeste ...
The title compound, [Co(C(27)H(25)O(2)P(2))I(C(3)H(9)P)], was synthesized by the addition of 1-iodo-butane to a solution of the parent cobalt complex {1,3-bis-[(diphenyl-phosphan-yl)-oxy]prop-2-yl}bis-(trimethyl-phosphane)cobalt(II). Two five-membered cobaltocycles with considerable ring bending (sum of inter-nal angles = 516.4 and 517.7°) are formed through two P atoms of the PPh(2) groups and a metallated Csp(3) atom. The Co(II) atom is centered in a trigonal-bipyramidal configuration. ...
Levan, fructose-composed biopolymer of bacterial origin, has potential in biotechnology due to its prebiotic and immunostimulatory properties. In this study levan synthesized by levansucrase from Pseudomonas syringae was thoroughly characterized and used as multifunctional biocompatible coating material for microelement-nanoparticles (NPs) of selenium, iron and cobalt. Transmission electron microscopy (TEM), hydrodynamic size measurements (DLS) and X-ray photoelectron spectroscopy (XPS) showed t ...
The sublimation of cobalt trifluoride was studied using the Knudsen effusion method combined with mass spectrometry. The pressure of F was directly measured for decomposition of CoF(3)(s) into CoF(2)(s). The average kinetic energy of CoF(2)(+), CoF(+) and Co(+) fragment ions was determined and the relative ionisation cross section curves measured from 6 eV to 100 eV. Thermodynamic functions of gaseous CoF(3) and Co(2)F(6), were evaluated from geometrical and vibrational parameters provided from ...
Twenty four male rats weighing between 120-130g were randomly assigned into four groups. Group A was fed normal diet; Group B, C and D were fed hypercholesterolemic diet (i.e. 20% fat + 1% cholesterol) for two weeks to establish hypercholesterolemia. Thereafter, Group B were maintained on hyper diet, while C and D were fed 5% and 10% Sesamum indicum seed oil supplemented diet for four weeks. The liver and kidney were removed, dried and powdered. The concentrations of iron, zinc, cobalt, manganes ...
This study was conducted to determine the effects of anticipated future level of CO2 on growth and dry matter partitioning of mungbean (Vigna radiata). Plants were grown from seedlings to maturity inside the open top chamber under amhient CO2 (350 +/- 25 microL L(-1)) and elevated CO2 (600 +/- 50 microL L(-1)) at Indian Agricultural Research Institute, New Delhi (India). Plants were harvested at 20, 35 and 50 days after germination. Mungbean plants grown under elevated CO2 concentration resulted ...
A wet chemical approach from organometallic reactants allowed the targeted synthesis of Co@Fe(2)O(3) heterodimer and CoFe(2)O(4) ferrite nanoparticles. They display magnetic properties that are useful for magnetic MRI detection. ...
Luminescent organometallic platinum(II) compounds are of interest as phosphors for organic light emitting devices. Their emissive properties can be tuned by variation of the ligands or by specific electron-withdrawing or electron-donating substituents. Different ancillary ligands can have a profound impact on the emission color and emission efficiency of these complexes. We studied the influence of sterically hindered, aryl-substituted β-diketonates on the emission properties of C^C* cyclometal ...
To test the hypothesis that the voltage-insensitive background leak K+ channel is responsible for the oxygen-sensitive properties of glomus cells in the rat carotid body (CB) we used Ba2+, a non-specific inhibitor of K+ currents. In vitro changes in cytosolic calcium ([Ca2+]c) and chemosensory discharge were studied to measure the effect of Ba2+. In normal Tyrode buffer, Ba2+ (3 and 5 mM) significantly increased carotid sinus nerve (CSN) discharge over baseline firing rates under normoxia (PO2 a ...
The activation of propane and isobutane in acidic zeolite H-ZSM-5 in the presence of both CO and H2O has been studied by in situ solid-state NMR and GC analysis. Evidence was provided for the conversion of propane to isobutyric acid at 373-473 K by cleavage of the C-C bond; methane and ethane are also produced. Isobutane is transformed into pivalic acid with simultaneous production of hydrogen. The low conversion (1-2%) at this temperature was rationalized by the existence of a small number of s ...
The distribution of heavy metal concentration in water and sediment samples from Ero River in South western, Nigeria was carried out for a period of dry and wet season. For both seasons Ni, Cd, Co were not detected in the water samples, while all metal examined were detected in the sediment samples. The concentrations of heavy metals were higher in the sediments than water sample. On the average the concentration of most the heavy metals appears higher in the dry season than wet season. The resu ...
METALS dissolved in natural waters often become sorbed onto oxide or clay minerals, so that prediction of their chemical behaviour and transport properties requires knowledge of the structure and bonding of metal species at the solid/water interface1. For many sorption systems, X-ray absorption spectroscopy (XAS) can be used to determine the identity and number of nearest-neighbour atoms and interatomic distances in aqueous complexes on solid surfaces, and thus to identify the dominant type of s ...
(C3N2H5)2[CoCl4] (ICC) was characterized in a wide temperature range by the single-crystal X-ray diffraction method. Differential scanning calorimetry revealed two structural phase transitions: continuous at 245.5 K (from phase I to II) and a discontinuous one at 234/237 K (cooling/heating) (II → III). ICC adopts monoclinic space groups C2/c and P21/c in phase (I) and (III), respectively. The intermediate phase (II) appears to be incommensurately modulated. Dynamic properties of polycrystallin ...
Copper amine oxidases (CAOs) contain 2,4,5-trihydroxyphenylalanyl quinone (TPQ) and a copper ion in their active sites, catalyzing amine oxidation to aldehyde and ammonia concomitant with the reduction of molecular oxygen to hydrogen peroxide. Kinetic studies on the CAO from bovine serum (BSAO) [Su and Klinman (1999) Biochemistry 37, 12513-12525] and the recent reports on the cobalt substituted form of the enzyme from Hansenula polymorpha (HPAO) [Mills and Klinman (2000) J. Am. Chem. Soc. 122, 9 ...
  • C. Zimmermann,
  • 2006 IEEE 4th World Conference on Photovoltaic Energy Conference
  • 2006
A set of representative miniature solar arrays was built, featuring triple junction cells with a range of typical production defects. The evolution of these cracks throughout several thousand simulated eclipse phases was studied with the help of electroluminescence imaging and pulsed solar simulator measurements. In addition, the effect of sine vibration and acoustic noise was analyzed by monitoring cell cracks on actual flight panels throughout their testing sequences. A power law dependence wa ...
Silver tungsten-carbide (AgWC) has been used for contact materials of low surge type vacuum interrupter because of their properties such as low chopping current and low erosion. However the interrupting capability of AgWC is relatively less than CuCr. Generally, in order to increase the interrupting capability, axial magnetic field (AMF) is applied for large rated currents. On the other hand, it is known that the contact materials greatly affect the interrupting capability and chopping current. ...
Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with a tridendate Schiff base prepared by condensation of ethyl 2-amino-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxylate with (3Z)-4-hydroxypent-3-en-2-one were synthesized and characterized on the basis of elemental analysis, molar conductance measurements, magnetic susceptibility values, UV-Vis, IR,EPR and NMR spectral data wherever possible. Spectral studies show that the ligand behaves as tridentate chelating agent and bonded to the metal ...
PURPOSE This study aimed to evaluate the role of the implant/abutment system on torque maintenance of titanium retention screws and the vertical misfit of screw-retained implant-supported crowns before and after mechanical cycling. MATERIALS AND METHODS Three groups were studied: morse taper implants with conical abutments (MTC group), external-hexagon implants with conical abutments (EHC group), and external-hexagon implants with UCLA abutments (EHU group). Metallic crowns casted in cobalt-ch ...
In the present study, the contents of Zn, Fe, Cu, Mn, Co, Ni, Pb, Cd, Cr, Al, Ca, Mg, and K in Agaricus campestris, Agrocybe cylindracea, Collybia dryophila, Helvella leucopus, Russula delica, Tricholoma auratum, Amanita ovoidea, Melanoleuca excissa, Rhizopogon roseolus, Russula chloroides, Volvoriella gloiocephala, Lyophyllum decastes, Morcella angusticeps, Morchella esculenta and Morcella eximia collected from Isparta, Mugla, and Osmaniye provinces (Turkey) were determined by inductively coupl ...
Origination of electron magnetic chiral dichroism in cobalt-doped ZnO dilute magnetic semiconductors Z.H. Zhang,a,c,⇑ H.L. Tao, Ming He and Quan Li Liaoning Key Materials Laboratory for Railway, School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028, China Department of Physics, Dalian Jiaotong University, Dalian 116028, China Department of Physics, The Chinese University of Hong Kong, Shatin, New Territory, Hong Kong SAR, China ...
A study into the effects of atmospheric pollution on the health of people living in the city of Parma (population 170,000) shows motor vehicle traffic of average density and light industrial activities that have little impact on air pollution. General mortality and hospitalisation for all causes and for DRG specific were considered as sanitary events. The day values of the total PT, PM10, SO2 and NO2, CO and benzene were analysed. In addition, atmospheric conditions and outbreaks of flu were con ...
We investigated the effects of tumor necrosis factor-alpha (TNF alpha), a cytokine produced as one aspect of inflammatory reactions, on the intracellular free calcium concentration in single pituitary cells using a calcium-sensitive fluorescent dye, indo-1, and a digital imaging fluorescence microscopic system. TNF alpha induced an increase in intracellular free calcium immediately after administration, reaching a peak after 30 sec and then returning to nearly the basal level after 120 sec in th ...
The formation of ternary ion-association complexes of Co(II) with 4-(2-pyridylazo)resorcinol (PAR) and tetrazolium salts (TS) - (3-(4,5-dimethylThiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and 3-(2-naphtyl)-2,5-diphenyl-2H-tetrazolium chloride (TV) - were investigated with the aid of the extraction-spectrophotometric method. The optimum conditions for the extraction of Co(II) were found. On the basis of the experimental data and their mathematical treatment the association process in ...
The local application of cobalt reversibly blocks calcium-channel conductance and therefore synaptic transmission. In this study pretreatment with a solution of cobalt (100 mM) in the nucleus tractus solitarii (NTS) of anaesthetized rats significantly blocked the apnea (P < 0.01) and arterial hypotension induced by L-glutamate (25 mM) and N-methyl-D-aspartate (0.4 mM) microinjected in the NTS. We conclude that cobalt causes these effects by acting at the postsynaptic level. ...
Four potential tetradentate ligands of formulae 1,2-bis-(3,5-di-tert-butyl-2-hydroxybenzamido)ethane (H(4)L(1), 1), 1,2-bis-(3,5-di-tert-butyl-2-hydroxybenzamido)propane (H(4)L(2), 2), 1,2-bis-(3,5-di-tert-butyl-2-hydroxybenzamido)benzene (H(4)L(3), 3) and 1,8-bis-(3,5-di-tert-butyl-2-hydroxybenzamido)naphthalene (H(4)L(4), 4) have been prepared and the crystal structures of three of them (1, 3 and 4) determined by single crystal X-ray diffraction. The investigation of their complexing ability t ...