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The results of a study of the reaction between ammonium m-vanadate and sodium oxalate in strong sulfuric acid solution are given. It has been found that the latter is a suitable and convenient primary standard for solutions of quinquevalent vanadium. 相似文献
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以苯乙酰氯和苯甲醚为起始原料,经酰化、缩合、消除、水解、成环、脱保护、氢化还原等反应合成了抗凝血灭鼠剂杀它仗——3-{3-[4-(4-三氟甲基苄氧基)苯基]-1,2,3,4-四氢化萘基}-4-羟基香豆素,总收率8.4%,其结构经1H NMR和IR确证。 相似文献
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Ya. L. Garazd E. M. Kornienko L. N. Maloshtan M. M. Garazd V. P. Khilya 《Chemistry of Natural Compounds》2005,41(5):508-512
3,4-Cyclocondensed coumarin O-glycopyranosides containing glucose, galactose, xylose, and arabinose were synthesized by condensation
of potassium salts of hydroxycoumarins and acetobromosugars. 7-(β-D-Galactopyranosyloxy)-2,3-dihydrocyclopenta[c]chromen-4-one,
3-(β-D-xylopyranosyloxy)-7,8,9,10-tetrahydrobenzo[c]chromen-6-one, and 3-(α-D-arabinopyranosyloxy)benzo[c]chromen-6-one exhibited
distinct anticoagulant activity.
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Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 416–419, September–October, 2005. 相似文献
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Bovine lung thrombomodulin was partially purified, and immobilized on agarose gel (Sepharose 4B). Immobilized thrombomodulin inhibited the procoagulant activity of thrombin, and enhanced the thrombin-catalyzed protein C activation. The plasma recalcification time test showed that immobilized thrombomodulin prolonged plasma clotting time. It is suggested that the immobilization of thrombomodulin will provide an antithrombogenic biomaterial able to convert thrombin from a procoagulant to an anticoagulant enzyme. 相似文献
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Lateral (L) cilia of freshwater mussel (Margaritana margaritifera and Elliptio complanatus) gills can be arrested in one of two unique positions. When treated with 12.5 mM CaCl2 and 10(-5) M A23187 they arrest in a "hands up" position, ie, pointing frontally. When treated with approximately 10 mM vanadate (V) they arrest in a "hands down" position, ie, pointing abfrontally. L-cilia treated with 12.5 mM CaCl2 and 1 mM NaN3 also arrest in a "hands down" position; substitution of 20 mM KCl and 1 mM NaN3 causes cilia to move rapidly and simultaneously to a "hands up" position. The observations suggest that there are two switching mechanisms for activation of active sliding in ciliary beat one at the end of the recovery stroke and the other at the end of the effective stroke; the first is inhibited by calcium and the second by vanadate or azide. This is consistent with a model of ciliary beating where microtubule doublet numbers 1, 2, 3, and 4 are active during the effective stroke while microtubule doublets numbers 6, 7, 8, and 9 are passive, and the converse occurs during the recovery stroke. 相似文献
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A spectrophotometric method for determining some penicillins has been developed. A known volume of the penicillin solution-in phosphate buffer of pH 6.8 is boiled with ammonium vanadate solution-in sulphuric acid medium-for 10 min and the absorbance of the colour formed is measured at 750 nm. The excess of vanadate can also be determined volumetrically. The method has been successfully applied for the determination of penicillin G sodium, phenoxymethyl penicillin, ampicillin sodium, phenethicillin potassium, cloxacillin sodium and methicillin sodium. The procedure is also used for analysing some pharmaceutical preparations of these drugs, e.g., injections. The results obtained are in agreement with those of the B P 1973 methods. 相似文献
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P. K. Sinhamahapatra V. K. Sharma S. Sinhamahapatra S. K. Bhattacharyya 《Reaction Kinetics and Catalysis Letters》1977,7(2):171-174
Oxidation of toluene vapors over fused bismuth vanadate catalysts of various compositions in fixed bed has been studied. The optimum conversion of toluene to benzaldehyde is related to the Bi2O3 content of the catalyst. The composition Bi2O3–V2O5(2575) and Bi2O3–V2O5 (4060) are highly active and selective for the oxidation of toluene to benzaldehyde.
. Bi2O3 . Bi2O3V2O5, 2575 4060, .相似文献
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Aluminum vanadate (AlVO4) shows a broad-band emission peaking at 620 nm at temperatures below 100°K. The luminescence is discussed in connection with the crystal structure. 相似文献
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《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1982,38(2):253-259
The i.r. spectra of some phosphate—arsenate strontium apatites and phosphate—vanadate strontium apatites have been studied and the assignments of their bands realized. It is shown that the symmetry of the distinct anions depends on the apatitic composition and it is suggested the existence of a mechanism of continuous anion migration throughout the apatite lattice. 相似文献
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P. K. Sinhamahapatra S. K. Bhattacharyya 《Journal of Thermal Analysis and Calorimetry》1979,15(2):233-249
Physicochemical properties of bismuth vanadate catalysts with varying compositions, e.g., Bi4V6O21-6 1/2H2O·1
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NH3; Bi6V2O14·3 H2O; Bi6V4O19·6 H2O have been studied by chemical analysis, differential thermal analysis, thermogravimetry, infrared, X-ray diffraction, surface area and magnetic susceptibility techniques.The endotherms, in all the cases, prior to exo ones are due to stepwise dehydration and those following exochanges are due to decomposition of adsorbed impurities, sintering and melting, etc. The last endopeak, in all the cases, however is due to melting. The exochanges are attributed to stepwise phase transitions. The V-0 stretching in all the compounds is characteristic of polyvanadates. Two types of vanadium-oxygen bonds e.g., V=O and V-O -V are characterized by IR analysis. The fresh first and third vanadates are amorphous whereas the second one is crystalline. The exochanges (presumably due to disorder-order transitions) are suggested to be related to displacement of oxygen anions. The precipitated vanadates are similar with their corresponding solid state reaction products of Bi2O3 and V2O5 when they are heated at elevated temperature. The fresh as well as treated vanadates are diamagnetic. These systems display maximum surface area at the temperature corresponding to complete dehydration. The composition of the precipitated vanadates is not ultimately defined by Bi/V ratio and the binary compound consequently formed.
Zusammenfassung Die physikalisch-chemischen Eigenschaften von Bismuthvanadat-Katalysatoren verschiedener Zusammensetzung, z.B. Bi4V6O21·6 2 1 H2O·1 2 1 NH3; Bi6V2O14·3 H2O; Bi6V4O19·6 H2O wurden durch chemische Analyse, Differentialthermoanalyse, Thermogravimetrie, Infrarot, Röntgendiffraktion, Oberflächenmessung und magnetische Susceptibilitätsmessung untersucht. In jedem Fall werden die den Exo-Änderungen vorangehenden Endo-Änderungen durch stufenweise Dehydratisierung verursacht und diejenigen, welche den Exo-Änderungen folgen, durch Zersetzung adsorbierter Verunreinigungen, Sinterung und Schmelzen. Der letzte Endopeak ist jedoch in jedem Falle dem Schmelzen zuzuschreiben. Die Exo-Änderungen werden stufenweisen Phasenübergängen zugeschrieben. In allen Verbindungen ist die V-O Dehnung für die Polyvanadate charakteristisch. Zwei Typen von Vanadium-Sauerstoff Bindungen, z. B. V=O und V-O-V wurden durch IR-Analyse charakterisiert. Die frisch synthetisierten ersten und dritten Vanadate sind amorph, während das zweite kristallin ist. Die (vermutlich durch Unordnung-Ordnungs Übergänge verursachten) Exo-Änderungen sind wahrscheinlich mit der Bewegung der Sauerstoff-Anionen verbunden. Die gefällten Vanadate sind — wenn sie auf hohe Temperaturen erhitzt werden — ihren entsprechenden Festphasen-Reaktionsprodukten Bi2O3 und V2O5 ähnlich. Die ursprünglichen wie die behandelten Vanadate sind diamagnetisch. Diese Systeme weisen die maximale Oberfläche bei der ihrer vollständigen Dehydratisierung entsprechenden Temperature auf. Die Zusammensetzung der gefällten Vanadate wird letzten Endes nicht durch. ihr Bi-V-Verhältnis und die in der Folge entstandene Binärverbindung bestimmt.
Résumé Les propriétés physico-chimiques des catalyseurs au vanadate de bismuth, de diverses compositions, par ex. Bi4V6O21 · 6 2 1 H2O · 1 2 1 NH3,Bi6V2Oi14 · 3H2O, Bi6V4O19 · 6H2O, ont été étudiées par analyse chimique, analyse thermique différentielle, thermogravimétrie, spectroscopie infrarouge, diffraction des rayons X, mesures de surfaces spécifiques et de susceptibilité magnétique.Dans tous les cas, les phénomènes endothermiques qui précèdent ceux de nature exothermique sont dus à la déshydratation par étapes; les phénomènes endothermiques qui suivent ceux de nature exothermique sont dus aux impuretés adsorbées, au frittage, à la fusion, etc ... Cependant, le dernier pic endothermique est toujours dû à la fusion. Les changements exothermiques sont attribués à des transitions de phases par étapes. La déformation V-0 dans tous les composés est caractéristique des polyvanadates. Deux types de liaisons vanadium-oxygène, par ex. V=O et V-O-V ont été caractérisés par analyse infrarouge. Le premier et le troisième vanadate, fraîchement préparés, sont amorphes alors que le second est cristallisé. Les. phénomènes exothermiques (probablement dus à des transitions désordre-ordre) sont sans doute en rapport avec le déplacement des anions oxygène. Les vanadates précipités — si on les. chauffe jusqu'à une température élevée — sont similaires aux produits correspondants, obtenus par réaction à l'état solide entre Bi2O3 et V2O5. Les vanadates fraîchement préparés ainsi que ceux qui ont subi un traitement thermique, sont diamagnétiques. Ces systèmesmontrent une surface spécifique maximalé à la température correspondant à la déshydratation complète. La composition des vanadates précipités n'est pas finalement définie par le rapport Bi/V et le composé binaire formé par la suite.
- - , , Bi4V6O21 · 6.5 2 ·1.5 NH3; Bi6V2O14 · 2; Bi6V4O19· 6H2O , , , , - , . , , , , , . . . . V- . - : V= V--V. , — . , (-, -) . , Bi2O3 V2O5 . , . , . Bi/V, a, , .相似文献
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SUN Di GAO Wenqing WU Peng LIU Jie LI Shengmei LI Shilin YU Meili NING Meng BAI Ru LI Tong LIU Ying CHEN Chunying 《高等学校化学研究》2021,37(5):1085-1091
Extracorporeal membrane oxygenation(ECMO) has emerged as a viable treatment in severe cases of acute respiratory distress syndrome, acute respiratory failure, and adult respiratory distress syndrome. However, thromboembolic events stemming from the use of ECMO devices results in significant morbidity and mortality rates; the inner surface of the ECMO tubing comes into contact with the blood and can readily initiate coagulation. In addition, the tubing needs to be continually replaced due to thromboses on the inner tube wall, which not only increases the risk of infection but also the economic burden. Despite considerable effort, a surface modification strategy that effectively addresses these challenges has not yet been realized. In this study, we developed an integrated hollow core-shell-shell hydrogel tube of gelatin/alginate/acrylamide-bacterial nanocellulose(GAA) that meets the anticoagulant requirements for the inner tubing layer as well as the highly elastic soft material needed for the outer layer. Using static blood from healthy volunteers, we confirmed that the platelets or coagulation is not stimulated by the GAA tubing. Importantly, experiments with dynamic blood also demonstrated that the inner layer of the tubing does not elicit blood clotting. The one-pot-synthesized process may provide guidance for the design of anticoagulation tubes used clinically. 相似文献
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V. I. Pet’kov M. V. Sukhanov A. S. Shipilov V. S. Kurazhkovskaya E. Yu. Borovikova N. V. Sakharov M. M. Ermilova N. V. Orekhova 《Russian Journal of Inorganic Chemistry》2013,58(9):1015-1021
Mixed vanadate phosphates in the systems MZr2(VO4) x (PO4)3 ? x , where M is an alkali metal, were synthesized and studied by X-ray diffraction, electron probe microanalysis, and IR spectroscopy. Substitutional solid solutions with the structure of the mineral kosnarite (NZP) are formed at the compositions 0 ≤ x ≤ 0.2 for M = Li; 0 ≤ x ≤ 0.4 for M = Na; 0 ≤ x ≤ 0.5 for M = K; 0 ≤ x ≤ 0.3 for M = Rb; and 0 ≤ x ≤ 0.2 for M = Cs. Apart from the high-temperature NZP modification, lithium vanadate phosphates LiZr2(VO4) x (PO4)3 ? x with 0 ≤ x ≤ 0.8 synthesized at temperatures not exceeding 840°C crystallize in the scandium tungstate type structure. The crystal structures of LiZr2(VO4)0.8(PO4)2.2 (space group P21/n, a = 8.8447(6) Å, b = 8.9876(7) Å, c = 12.3976(7) Å, β = 90.821(4)○, V = 985.4(1) Å3, Z = 4) and NaZr2(VO4)0.4(PO4)2.6 (space group $R\bar 3c$ = 8.8182(3) Å, c = 22.7814(6) Å, V = 1534.14(1) Å3, Z = 6) were refined by the Rietvield method. The framework of the vanadate phosphate structure is composed of tetrahedra (that are statistically occupied by vanadium and phosphorus atoms) and ZrO6 octahedra. The alkali metal atoms occupy extra-framework sites. 相似文献