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Vaddypally Shivaiah - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and characterization of a reduced heteropoly-tungstoVanadate: (NH_4)_7[V^vO_4W _10 ^IV V _2 ^IV O_36].ca. 22H_2O
Journal of Chemical Sciences, 2002Co-Authors: Vaddypally ShivaiahAbstract:The compound (NH_4)_7[ V^vO_4W _10 ^VI V _2 ^VI O_36]·ca.22H_2O (1) has been synthesized from an aqueous ammonium acetate buffer (pH 4) containing Sodium Vanadate, Sodium rungstate_and Sodium dithionite. Compound (1) crystallizes in a cubic space group Fm — 3 , with a = 22.2001(6) Å and Z = 8. The anion [V^vO_4W _10 ^VI V _2 ^IV O_36]^7- is a typical Keggin type structure with V^VO_4 as the central tetrahedron. (1) has further been characterized by elemental analyses, redox titration, IR, EPR, and electronic spectroscopy and room temperature magnetic moment measurement.
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Synthesis and characterization of a reduced heteropoly-tungstoVanadate: (NH4)7[VvO4W 10 IV V 2 IV O36].ca. 22H2O
Journal of Chemical Sciences, 2002Co-Authors: Vaddypally Shivaiah, Samar K. DasAbstract:The compound (NH4)7[ VvO4W 10 VI V 2 VI O36]·ca.22H2O (1) has been synthesized from an aqueous ammonium acetate buffer (pH 4) containing Sodium Vanadate, Sodium rungstate_and Sodium dithionite. Compound (1) crystallizes in a cubic space groupFm — 3, witha = 22.2001(6) A and Z = 8. The anion [VvO4W 10 VI V 2 IV O36]7- is a typical Keggin type structure with VVO4 as the central tetrahedron. (1) has further been characterized by elemental analyses, redox titration, IR, EPR, and electronic spectroscopy and room temperature magnetic moment measurement.
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Synthesis and characterization of a reduced heteropolytungstoVanadate: (NH4)7[VVO4WVI10VIV2O36].ca. 22H2O
2002Co-Authors: Vaddypally Shivaiah, Samar K. DasAbstract:The compound (NH 4 ) 7 [V V O 4 W V I 1 0 V I V 2 O 3 6 ].ca.22H 2 O (1) has been synthesized from an aqueous ammonium acetate buffer (ph 4) containing Sodium Vanadate, Sodium tungstate_and Sodium dithionite. Compound (1) crystallizes in a cubic space group Fm3, with a = 22.2001(6)A and Z=8. The anion [V V O 4 W V I 1 0 V I V 2 O 3 6 ] 7 - is a typical Keggin type structure with V V O 4 as the central tetrahedron. (1) has further been characterized by elemental analyses, redox titration, IR, EPR, and electronic spectroscopy and room temperature magnetic moment measurement.
Samar K. Das - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and characterization of a reduced heteropoly-tungstoVanadate: (NH4)7[VvO4W 10 IV V 2 IV O36].ca. 22H2O
Journal of Chemical Sciences, 2002Co-Authors: Vaddypally Shivaiah, Samar K. DasAbstract:The compound (NH4)7[ VvO4W 10 VI V 2 VI O36]·ca.22H2O (1) has been synthesized from an aqueous ammonium acetate buffer (pH 4) containing Sodium Vanadate, Sodium rungstate_and Sodium dithionite. Compound (1) crystallizes in a cubic space groupFm — 3, witha = 22.2001(6) A and Z = 8. The anion [VvO4W 10 VI V 2 IV O36]7- is a typical Keggin type structure with VVO4 as the central tetrahedron. (1) has further been characterized by elemental analyses, redox titration, IR, EPR, and electronic spectroscopy and room temperature magnetic moment measurement.
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Synthesis and characterization of a reduced heteropolytungstoVanadate: (NH4)7[VVO4WVI10VIV2O36].ca. 22H2O
2002Co-Authors: Vaddypally Shivaiah, Samar K. DasAbstract:The compound (NH 4 ) 7 [V V O 4 W V I 1 0 V I V 2 O 3 6 ].ca.22H 2 O (1) has been synthesized from an aqueous ammonium acetate buffer (ph 4) containing Sodium Vanadate, Sodium tungstate_and Sodium dithionite. Compound (1) crystallizes in a cubic space group Fm3, with a = 22.2001(6)A and Z=8. The anion [V V O 4 W V I 1 0 V I V 2 O 3 6 ] 7 - is a typical Keggin type structure with V V O 4 as the central tetrahedron. (1) has further been characterized by elemental analyses, redox titration, IR, EPR, and electronic spectroscopy and room temperature magnetic moment measurement.
M. J. Poznansky - One of the best experts on this subject based on the ideXlab platform.
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The insulin-mimetic agent Vanadate promotes receptor endocytosis and inhibits intracellular ligand-receptor degradation by a mechanism distinct from the lysosomotropic agents.
Diabetes, 1996Co-Authors: I. G. Fantus, R. George, Shangguo Tang, P. Chong, M. J. PoznanskyAbstract:Vanadate (Sodium orthoVanadate) is an insulin-mimetic agent and phosphotyrosine phosphatase inhibitor that has been proposed as a potential therapeutic agent for diabetes. We previously reported that Vanadate decreased the number of cell-surface insulin receptors but inhibited receptor degradation in cultured lymphocytes (IM-9) (1). To determine whether Vanadate affected receptors without intrinsic tyrosine kinase activity, its effects on LDL and transferrin receptors and their ligands were examined. Vanadate exposure resulted in a doseand time-dependent decrease in LDL binding to cultured human fibroblasts associated with a decrease in cell surface receptor number while total solubilized cell LDL receptors increased. Vanadate also inhibited the LDLmediated downregulation of total cellular LDL receptors in the absence and presence of cycloheximide consistent with an inhibition of LDL receptor degradation. In the case of the ligand, Vanadate augmented the accumulation of intact 125 I-LDL associated with an inhibition of up to 80% of the ability of LDL to decrease cholesterol synthesis. Since these actions were similar to the effects of lysosomotropic agents, we examined the effect of Vanadate on intraendosomal pH using the fluorescent probe acridine orange. In contrast with chloroquine and NH 4 C1, Vanadate did not neutralize the pH of the acidic intracellular compartment. Furthermore, after a transient insulin-like effect, chronic exposure to Vanadate diminished 125 I-diferric transferrin binding to rat adipocytes. In contrast with the inhibitory action of NH 4 C1, intracellular 59 Fe uptake remained unaffected and was proportional to cell-surface binding capacity in the presence of Vanadate. These data demonstrate a chronic effect of Vanadate to promote the accumulation of intracellular receptors and to inhibit ligand and receptor degradation. The latter effect is not mediated by pH changes, appears to be localized to a late endosoma/Mysosomal compartment, and suggests a possible role for tyrosine dephosphorylation in the regulation of receptor-ligand degradation.
Mao-fa Jiang - One of the best experts on this subject based on the ideXlab platform.
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Study of the Effect of Roasting System on Leaching Process of Sodium Vanadium Residue
DEStech Transactions on Materials Science and Engineering, 2017Co-Authors: Bao-yao Liu, Pei-yang Shi, Mao-fa JiangAbstract:Reasonable choice of Sodium roasting process system for vanadium and solution purification plays an important role. The effects of roasting process on the migration behavior of V , Si and P were studied systematically by means of XRD and fluorescence spectr oscopy. The results show that the vanadium iron spinel phase disappears gradually with the increase of calcination temperature, and the diffraction peaks of Sodium Vanadate, Sodium silicate and Sodium chromate are gradually enhanced. With the increase of c alcination temperature and the reaction time, the leaching efficiency of vanadium in vanadium slag increased first and then decreased. When the calcination temperature was 860 ° C , the maximum leaching efficiency of vanadium was 91.0% . The leaching efficien cy of Si, P and Cr in vanadium slag is gradually increased, and the higher the temperature, the higher the leaching efficiency of these elements is, and the suitable process is roasting Temperature 860 ° C and time 45min.
I. George Fantus - One of the best experts on this subject based on the ideXlab platform.
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Enhanced sensitivity of insulin-resistant adipocytes to Vanadate is associated with oxidative stress and decreased reduction of Vanadate (+5) to vanadyl (+4).
Journal of Biological Chemistry, 2001Co-Authors: David Ennis, Robert Lai, Elena Bogdanovic, Rinna Nikolov, Lisa Salamon, Claire Fantus, Hoang Le-tien, I. George FantusAbstract:Abstract Vanadate (Sodium orthoVanadate), an inhibitor of phosphotyrosine phosphatases (PTPs), mimics many of the metabolic actions of insulin in vitro and in vivo. The potential of Vanadate to stimulate glucose transport independent of the early steps in insulin signaling prompted us to test its effectiveness in an in vitro model of insulin resistance. In primary rat adipocytes cultured for 18 h in the presence of high glucose (15 mm) and insulin (10−7 m), sensitivity to insulin-stimulated glucose transport was decreased. In contrast, there was a paradoxical enhanced sensitivity to Vanadate of the insulin-resistant cells (EC50 for control, 325 ± 7.5 μm; EC50 for insulin-resistant, 171 ± 32 μm; p < 0.002). Enhanced sensitivity was also present for Vanadate stimulation of insulin receptor kinase activity and autophosphorylation and Akt/protein kinase B Ser-473 phosphorylation consistent with more effective PTP inhibition in the resistant cells. Investigation of this phenomenon revealed that 1) depletion of GSH with buthionine sulfoximine reproduced the enhanced sensitivity to Vanadate while preincubation of resistant cells withN-acetylcysteine (NAC) prevented it, 2) intracellular GSH was decreased in resistant cells and normalized by NAC, 3) exposure to high glucose and insulin induced an increase in reactive oxygen species, which was prevented by NAC, 4) EPR (electron paramagnetic resonance) spectroscopy showed a decreased amount of vanadyl (+4) in resistant and buthionine sulfoximine-treated cells, which correlated with decreased GSH and increased Vanadate sensitivity, while total vanadium uptake was not altered, and 5) inhibition of recombinant PTP1Bin vitro was more sensitive to Vanadate (+5) than vanadyl (+4). In conclusion, the parodoxical increased sensitivity to Vanadate in hyperglycemia-induced insulin resistant adipocytes is due to oxidative stress and decreased reduction of Vanadate (+5) to vanadyl (+4). Thus, sensitivity of PTP inhibition and glucose transport to Vanadate is regulated by cellular redox state.
