Search results for "vanA"

Insulin-Mimetic Action of Vanadate

2001

Abstract — — The insulin-mimetic effect of vanadate is well established, and vanadate has been shown to improve insulin sensitivity in diabetic rats and humans. Although the exact mechanism(s) remain undefined, we have previously demonstrated a direct relation of intracellular free magnesium (Mg i ) levels to glucose disposal, to insulinemic responses following glucose loading, and to insulin-induced ionic effects. To investigate whether the insulin-mimetic effects of vanadate could similarly be mediated by Mg i , we utilized 31 P-nuclear magnetic resonance spectroscopy to measure Mg i in erythrocytes from normal (NL, n=10) and hypertensive (HTN, n=12) subjects, before and after incubation…

Effects of low temperature and pharmacological interventions on the responses of the isolated guinea-pig trachea

1992

Cooling the guinea-pig isolated trachea from 37°C to 20°C virtually abolished the response to CaCl2 (in K+-depolarized tissues) and depressed that to histamine (about 75% reduction), KCl and 5-hydroxytryptamine (around 50% inhibition) while the response to acetylcholine remained unaffected. A further cooling to 10°C was necessary to inhibit acetylcholine-induced contractions. Hyporesponsiveness to spasmogens by cooling was not associated with subsensitivity (increased EC50) except for 5-hydroxytryptamine. Contractile responses to KCl (50 mmol/l), histamine (1 mmol/l) and 5-hydroxytryptamine (0.1 mmol/l) in a Ca2+-free EGTA (0.1 mmol/l)-containing solution were inhibited by cooling to 20°C b…

EFFECTS OF VANADATE ON RESPONSES OF GUINEA-PIG ISOLATED TRACHEA TO SPASMOGENS

1993

Abstract The effects of vanadate on the contractility of the guinea-pig isolated trachea was examined. Vanadate (0·1 Mm) produced a sustained contraction that was abolished in Ca2+-free EGTA (0·1 Mm)-containing physiological salt solution but was resistant to verapamil (1 μm). Vanadate (0·1 Mm) depressed tracheal responses to CaCl2 (in Ca2+-free depolarizing solution), KCl, acetylcholine, histamine and 5-hydroxytryptamine. For vanadate (10 μm), the inhibition of spasmogenic responses only reached statistical significance for histamine and 5-hydroxytryptamine. Caffeine (1 Mm)-induced spasm (trachea at 20°C in the presence of indomethacin (2·8 μm)) was not affected by vanadate (10 μm-0·1 Mm).…

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A comparative study of photocatalytically active nanocrystalline tetragonal T zyrcon- type and monoclinic scheelite-type bismuth vanadate

2018

The authors from Vinča Institute of Nuclear Sciences acknowledge the financial support of the Ministry of Education, Science and Technological Development of the Republic of Serbia (Project no: 172056 ). The work of K. Smits was supported by Latvian National Research Program IMIS2 (Grant no. 302/2012 ).

Effective low temperature reduction of graphene oxide with vanadium(iii)

2014

Reduction of graphene oxide (GO) with vanadium(III) trichloride under various reaction conditions has been investigated. The results show that V(III) can be used as an efficient reducing agent for GO in aqueous solutions at low concentrations and in moderate temperatures under ambient conditions. The IR spectroscopy and X-ray photoelectron spectroscopy (XPS) show that the structure of the vanadium-reduced material is similar to reduced graphene oxide prepared using TiCl3 or hydrazine as a reducing agent. The electrical conductivity of the material is also similar in all cases. However, on the basis of the XPS results, vanadium-based reduction does not leave significant reductant impurities …

Proposal for a Dual Spin Filter Based on [VO(C 3 S 4 O) 2 ] 2–

2018

Polynuclear magnetic molecules often present dense electronic transmission spectra with many overlapping conduction spin channels. Single-metal complexes display a sparser density of states, which in the presence of a fixed external magnetic field makes them interesting candidates for spin filtering. Here we perform a DFT study of a family of bis- and tris-dithiolate vanadium complexes sandwiched between Au(111) electrodes and demonstrate that [VO(C3S4O)2]2– can behave as a dual spin filter. This means that an external electrical stimulus can switch between the selective transmission of spin-up and spin-down carriers. By using an electrostatic gate, we show that the onset for the spin-up co…

V-containing ZrO 2 inorganic yellow nano-pigments prepared by hydrothermal approach

2017

Abstract Recent results on the preparation, characterization and color properties of the V-containing ZrO 2 inorganic yellow nano-pigment are reported. A series of monoclinic V-ZrO 2 solid solution nanocrystals (V x Zr 1-x O 2 , being x = 0, 0.1, 0.02, 0.03, 0.04, 0.05, 0.065, 0.08 and 0.1) were prepared straightforward by hydrothermal processing of mixtures of zirconyl nitrate and ammonium metavanadate in water. Interestingly, the crystalline precipitated obtained by hydrothermal processing at 140 °C for 3 d was almost entirely V-containing ZrO 2 nanocrystals with the structure of monoclinic zirconia for the whole range of compositions. Lattice parameters changes along the series of prepar…

Changes in the local structure of nanocrystalline electrochromic films of hydrated nickel vanadium oxide upon ozone-induced coloration

2005

Hydrated thin films of nickel vanadium oxide (Ni1−xVxOy), made by reactive DC magnetron sputtering, were studied by x-ray absorption spectroscopy at the Ni and V K-edges using synchrotron radiation. The XANES signals were analysed within the full-multiple-scattering formalism, whereas EXAFS data were modelled within the multi-shell multiple-scattering approach. We found that transparent films exhibit a nanocrystalline NiO-type structure with homogeneous distribution of V ions substituting Ni ions. Exposure of the films to ozone resulted in dark brown coloration associated with an appearance of Ni3+ ions and accompanied by a modification of the local electronic and atomic structures of the V…

Mechanical activation conditions of the Fe2O3 and V2O3 mixture powders in order to obtain a nanometric vanadium spinel ferrite

1999

Abstract Co-milling of iron and vanadium oxides allows to obtain an intimate oxides mixture at a nanoscale, similar to a coprecipitate elaborated by soft chemistry. Reduction of such a mixture in the same temperature and oxygen partial pressure conditions (500°C and 10−25 Pa) as the soft chemistry products leads to a nanometric vanadium ferrite with the only spinel phase. The characterization of the powders is achieved by X-ray diffraction (XRD), scanning electron microscopy, infrared (IR) spectrometry, thermogravimetry and calorimetry. Homogeneity of grain size and chemical composition is reached if the initial oxides have similar grain size.