Search results for "Vanadate"
showing 10 items of 46 documents
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).…
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 ).
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…
The electronic structure of zircon-type orthovanadates: Effects of high-pressure and cation substitution
2012
The electronic structure of four ternary-metal oxides containing isolated vanadate ions is studied. Zircon-type YVO4, YbVO4, LuVO4, and NdVO4 are investigated by high-pressure optical-absorption measurements up to 20 GPa. First-principles calculations based on density-functional theory were also performed to analyze the electronic band structure as a function of pressure. The electronic structure near the Fermi level originates largely from molecular orbitals of the vanadate ion, but cation substitution influence these electronic states. The studied ortovanadates, with the exception of NdVO4, undergo a zircon-scheelite structural phase transition that causes a collapse of the band-gap energ…
Synthesis, structure and spectroscopic properties of luminescent GdVO 4 :Dy 3+ and DyVO 4 particles
2018
Part of this research was done during visit of D.J. to IFN-CNR CSMFO Lab. and FBK Photonics Unit, Povo-Trento, Italy, in the framework of the STSM (Grant No. 38223) from the project: COST Action MP 1401 Advanced Fibre Laser and Coherent Source as tools for Society, Manufacturing and Lifescience” (2014e2018). The authors from Vinca Institute of Nuclear Sciences acknowledge the financial support of the Ministry of Education, Science and Tech-nological Development of the Republic of Serbia (Project No: 45020 and 172056). L.T.N. Tran acknowledges the scholarship of the Ministry of Education and Training, Vietnam International Education Development. T. G. acknowledges the ERDF PostDoc project No…
Evaluation of Arsenate- and Vanadate-Associated Changes of Electrical Membrane Potential and Phosphate Transport inLemna gibbaG1
1989
Interference of arsenate and vanadate with phosphate uptake in Lemna gibba L. was studied by measuring voltage changes and (32P)phosphate uptake. Arsenate proved to be competitive with the highand low-affinity phosphate uptake system. It induced transient membrane potential changes of up to 120 mV which were similar to those induced by phosphate and indicated a cotransport mechanism with at least 2H+/H2As04. The amplitude of the transient arsenate-induced membrane depolarization was strongly influenced by phosphate starvation. A permanent membrane depolarization to the diffusion potential was achieved within 2 to 6 h in P-starved plants. Thus, arsenate is indeed a strongly competitive physi…
Synthetically persistent, self assembled [V(IV)2V(V)4] polyoxovanadates: facile synthesis, structure and magnetic analysis.
2011
Slow diffusion in a H-tube at room temperature of a methanolic solution of [VO(acac)(2)] (Hacac = acetylacetone) and 1,10-phenanthroline (phen) or 2,2'-bipyridine (bipy) into an aqueous solution of sodium pyrophosphate (Na(4)P(2)O(7)) resulted in the serendipitous formation of X-ray quality crystals of mixed-valent, hexameric oxovanadates of general formula [V(6)O(12)(OCH(3))(4)(L)(4)]·solv [L = 1,10-phenanthroline (phen) for 1· 2CH(3)OH · 4H(2)O (1a), and 2,2'-bipyridine (bipy) for 2· 4H(2)O (2a)]. These were characterized by single-crystal X-ray diffraction, IR, elemental and thermogravimetric analysis (TGA). A facile, rationalized synthetic route for the isolation of 1a and 2a could be e…
The spasmogenic effects of vanadate in human isolated bronchus
1997
1. Inhalation of vanadium compounds, particularly vanadate, is a cause of occupational bronchial asthma. We have now studied the action of vanadate on human isolated bronchus. Vanadate (0.1 microM-3 mM) produced concentration-dependent, well-sustained contraction. Its -logEC50 was 3.74 +/- 0.05 (mean +/- s.e.mean) and its maximal effect was equivalent to 97.5 +/- 4.2% of the response to acetylcholine (ACh, 1 mM). 2. Vanadate (200 microM)-induced contraction of human bronchus was epithelium-independent and was not inhibited by indomethacin (2.8 microM), zileuton (10 microM), a mixture of atropine, mepyramine and phentolamine (each at 1 microM), or by mast cell degranulation with compound 48/…
Lattice dynamics ofYVO4at high pressures
2010
We report an experimental and theoretical lattice-dynamics study of yttrium orthovanadate $({\text{YVO}}_{4})$ up to 33 GPa together with a theoretical study of its structural stability under pressure. Raman-active modes of the zircon phase are observed up to 7.5 GPa, where the onset of an irreversible zircon-to-scheelite phase transition is detected, and Raman-active modes in the scheelite structure are observed up to 20 GPa, where a reversible second-order phase transition occurs. Our ab initio total-energy calculations support that the second-order phase transition in ${\text{YVO}}_{4}$ is from the scheelite to the monoclinic M-fergusonite structure. The M-fergusonite structure remains u…