(1) If anionic production of quantum bumps in Limulus photoreceptors is mediated by changes in cyclic nucleotides, then the electrophysiological response of Limulus photoreceptors to tungstate may indicate a role for phosphodiesterase rather than adenylate cyclase in mediating light-induced cyclic nucleotide alterations in this cell.
(2) Film changer angiograms using conventional calcium-tungstate screen combinations.
(3) However, the tungstate effect was not very strong, and the P-2 type tended to change into the P-3.
(4) After staining with hematoxylin-phosphorus-tungstate, the vitelline epithelium of untreated and progesterone-treated rats showed a blue granulation.
(5) The addition of 1 mM tungstate to molybdate-containing media resulted in nearly complete loss of enzyme activity and decreased the intracellular concentration of molybdenum 10-fold.
(6) These studies show that the nontransformed, and the heat-, salt-, and ATP-transformed GRc from the rat liver cytosol can be separated chromatographically, and that the use of tungstate facilitates the resolution of these different receptor forms.
(7) The inactive enzyme obtained from cells grown in the presence of tungstate did not hold Mo but contained 1 mol of W. The content of Fe was not increased.
(8) The constitutive xanthine dehydrogenase and the inducible 2-furoyl-coenzyme A (CoA) dehydrogenase could be labeled with [185W]tungstate.
(9) The level of formate dehydrogenase of C. acidiurici increased 12-fold when 10(-7) M tungstate and selenite were present during growth.
(10) We evaluated six deproteinizing methods for determination of uric acid in serum by "high-performance" liquid chromatography with ultraviolet detection: those involving zinc hydroxide, sodium tungstate, trichloroacetic acid, perchloric acid, acetonitrile, and centrifugal ultrafiltration (with Amicon MPS-1 devices).
(11) Both xanthine dehydrogenase and formate dehydrogenase exhibited the highest level of activity if selenite and tungstate were present in that medium.
(12) Rare earth and barium fluorochloride screen-film combinations of different relative speeds were compared to conventional calcium tungstate systems in patients undergoing excretory urography under controlled conditions.
(13) Single molecules were contrasted with 2 percent potassium silico tungstate which gave better contrast and preservation of enzyme activity than ammonium molybdate.
(14) On the other hand, agents related to VRC and oxoanions of transient metals, such as ribonucleoside, vanadate, molybdate, tungstate and arsenate, exerted no effect on the DNA-cellulose binding ability of the receptor.
(15) Tungstate prevents the formation of NADH-nitrate reductase and FMNH(2)-nitrate reductase activities, but it causes superinduction of NADH-cytochrome c reductase activity.
(16) The results support the idea that NADH-nitrate reductase, FMNH(2)-nitrate reductase and NADH-cytochrome c reductase are activities of the same enzyme complex, and that in the presence of tungstate the 8S enzyme complex is formed but is functional only with respect to NADH-cytochrome c reductase activity.
(17) Rare earth and other new screens absorb a maximum of 1.5 times as much energy and emit twice as much light as comparable calcium tungstate screens.
(18) Furthermore, in vitro cytotoxicity experiments showed inhibition by tungstate of cartilage production in limb bud mesenchymal cultures at concentrations similar to those found in vivo.
(19) We evaluated the physical characteristics and contrast-dose-detail performance of 11 rare-earth and three calcium tungstate screen-film systems.
(20) The transformed and nontransformed GRc were also differentially fractionated by (NH4)2SO4: tungstate-treated (nontransformed) receptor required higher salt concentration and was precipitated at 55% saturation.
Tungsten
Definition:
(n.) A rare element of the chromium group found in certain minerals, as wolfram and scheelite, and isolated as a heavy steel-gray metal which is very hard and infusible. It has both acid and basic properties. When alloyed in small quantities with steel, it greatly increases its hardness. Symbol W (Wolframium). Atomic weight, 183.6. Specific gravity, 18.
(n.) Scheelite, or calcium tungstate.
Example Sentences:
(1) Moments later, explosive charges blasted free two tungsten blocks, to shift the balance of the probe so it could fly itself to a prearranged landing spot .
(2) This in vivo incorporation of tungsten was competitively hindered by molybdenum.
(3) The results of transmission measurements for neutrons, cobalt-60 gamma-rays, and 10 and 15 MV photons made with close-packed arrays of tungsten rods are presented.
(4) Using a tungsten microelectrode, activities of medullary inspiratory neurons were recorded around nucleus ambiguus.
(5) Treatment was administered with white light produced by a commercially available halogen-tungsten lamp.
(6) The results support the hypothesis that mild steel welding and to a lesser extent stainless steel welding with tungsten inert gas is associated with reduced semen quality at exposure in the range of the Danish process specific threshold limit values of welding.
(7) All xeroradiographic measurements were made with a tungsten target source with aluminum filtration at half-value layers of 1.5 to 1.56 mm Al.
(8) The electrode consists of a 30 gauge stainless steel cannula through which multiple strands of 13 micron insulated tungsten microwires are threaded.
(9) Under these conditions, blue absorbing intermediate(s) is (are) formed, the time constant of regeneration of rhodopsin is much faster than after long tungsten bleaches, and the kinetic equation is not valid.9.
(10) Dense projections of the presynaptic grid are most sensitive to hypoxia: their height, distinctness of the frame, and the intensity degree of phosphoric tungsten acid staining decrease.
(11) For larger angles some discrepancies appear which could be either due to increased filtration by tungsten (surface roughness) or limited applicability of the data used.
(12) The uptake of cobalt by macrophages in the presence of tungsten carbide was found to be increased.
(13) A previous study from this laboratory, using morphological and biochemical (LDH release) parameters, has shown that tungsten carbide-cobalt dust exhibits a greater cytotoxicity toward isolated macrophages than cobalt metal powder alone.
(14) After a recovery period of approximately one month, physiological recordings were made with tungsten micro-electrodes from the central nucleus of the inferior colliculus of animals with SOC lesions.
(15) A high prevalence of gout among workers of the mining industry and early age at the onset of disease suggest probable association of gout with some industrial factors (manganese, tungsten, molybdenum, bismuth).
(16) Biological systems show a marked preference for molybdenum over tungsten.
(17) To determine the physiological role of xanthine oxidase in renal ischemia, we depleted rats of xanthine oxidase by feeding tungsten.
(18) A cross-sectional study of 1,039 tungsten carbide (TC) production workers was carried out.
(19) Intercellular interconnections in neuropil of dorsal ganglia in the subpharyngeal complex and nerves have been studied in a mature snail (Helix pomatia), dimensions of the shell--3.0 X 3.5 sm, after double fixation (glutaraldehyde and osmium tetraoxide) and treatment with phosphoric tungsten acid.
(20) Images of DNA and ribosomal subunits contrasted by sputter shadowing with tungsten are shown.