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61.
The nitrosyl-hemoglobin (HbNO) is the carrier of nitric oxide (NO) which is the important messenger molecule displaying multiple physiologic and pathophysiologic roles. However it is still not clear for the fate of HbNO molecules during the venous-arterial transit. In this letter, the HbNO transition in vitro was studied by using the electron paramagnetic resonance (EPR) spectra. It was found that HbNO molecules were stable when oxygen did not exist in the system but not stable in aerobic conditions. The absorption spectra further revealed that the methemoglobin (metHb) was the product of HbNO in aerobic environment, showing that the HbNO changed to metHb when there were enough oxygen molecules in the system. 相似文献
62.
钙与 DBC-偶氮氯膦显色反应的研究及其在高纯氧化钇中钙的测定的应用 总被引:1,自引:0,他引:1
在PH8.5-9的液中,钙可与DBC-偶氮氯膦形成一种紫色的稳定配合物。该配合物在625nm处有最大吸收,表观摩尔吸光系数为2.6×10~4L.mol~(-1).cm~(-1),配合物组成为Ca:DBC-偶氮氯膦=1:1。在Zn-DTPA和乙二胺的存在下,较大量的Y~(3+)、Fe~(3+)及Cu~(2+)、Mo(Ⅵ)、Cr~(3+)等三十余种离子不干扰钙的测定。方法的选择性较好,利用本方法,并经简单萃取分离基体后,测定了高纯氧化钇和易切削钢中的微量钙,结果令人满意。标准加入试验回收率好。方法简便实用。 相似文献
63.
羧甲基壳聚糖/聚乙烯醇/甘油环氧树脂蛇笼型复合螯合膜的制备及对金属离子的吸附性能 总被引:4,自引:0,他引:4
以交联甘油环氧树脂交联的聚乙烯醇(PVA)为笼树脂,羧甲基壳聚糖(CCTS)为蛇树脂制备了具有蛇笼结构的复合螯合膜,研究了其对Cu^2 、Ni^2 、Pb^2 、Fe^3 、Zn^2 ,Hg”^2 、Cd^2 等金属离子的吸附性能,研究表明,该树脂对Cu^2 、Ni^2 、Pb^2 有较好的吸附性能,其中PVA是对Cu^2 的吸附的主要贡献者,而CCTS则是在对Ni^2 的吸附中起主要作用。该树脂可以用于含Cu^2 废水的处理。 相似文献
64.
Naotomo Dobashi 《Tetrahedron letters》2007,48(27):4669-4673
Palladium-1,2-bis(diphenylphosphino)ethane complex catalyzes regioselective Markovnikov addition of diphenylphosphine oxide to terminal alkynes in propionitrile, while the use of triarylphopshines, di(o-tolyl)phenylphosphine in particular, as the ligand leads to dehydrogenative double addition forming 1,2-diphenylphosphinyl-1-alkenes as major products. 相似文献
65.
Solubility of lanthanum oxide was measured by thermal analysis. The solubility in alkali cryolites is rather high, because of chemical reactions between lanthanum oxide and cryolites. In Li3AlF6-La2O3, alumina precipitates, in the other systems the mixed oxide LaAlO3 is formed. In La2O3-Li3AlF6 the eutectic point is at 9.5 mol% La2O3 and 755 °C. The eutectic points in La2O3-Na3AlF6 and La2O3-K3AlF6 are at 11.5 mol% La2O3, and at 937 and 934 °C, respectively. 相似文献
66.
Jason R McCarthyPatricia J Melfi Steven H CapettaChristian Brückner 《Tetrahedron》2003,59(46):9137-9146
The use of AgII as a removable template in synthetic porphyrin chemistry is described. Mild procedures for the insertion of AgII into chlorins and the demetallation of the [chlorinato]AgII complexes are delineated. The UV-vis spectra of the novel [chlorinato]AgII complexes are discussed. The diol cleavage products of [meso-tetraphenyl-2,3-diolchlorinato]silver(II) under a number of conditions are characterized and compared to those resulting from the cleavage of the corresponding free base diol chlorin or its NiII complex, highlighting the unique templating effect of AgII. The scopes and limits of electrospray ionization mass spectrometry (ESI-MS) for the analysis of AgII chlorins is described. The use of AgII as a templating metal is superior over NiII or ZnII for the preparation of free base pyrrole-modified porphyrins along metal templated pathways. 相似文献
67.
Posudievskii O. Yu. Kurys' Ya. I. Biskulova S. A. Malinovskii Yu. K. Pokhodenko V. D. 《Theoretical and Experimental Chemistry》2002,38(5):278-282
The possibility of the production of nanocomposites based on V2O5 and conducting polymers by direct intercalation of macromolecules of secondary doped polyaniline into the interlayer galleries of nanoparticles of aqueous V2O5 sol was demonstrated for the first time. The driving force of the intercalation process is substitution of the protons present in the galleries of the V2O5 by a polyaniline chain carrying a positive charge. 相似文献
68.
V. A. D’yakonov R. K. Timerkhanov A. G. Ibragimov U. M. Dzhemilev 《Russian Chemical Bulletin》2007,56(11):2232-2235
Catalytic cycloalumination of cyclonona-1,2-diene upon treatment with Et3Al and EtAlCl2 in the presence of Cp2ZrCl2, leading to 10-ethyl-10-aluminabicyclo[7.3.01,9]dodec-8-ene (1) and 11-ethyl-11-aluminatricyclo[10.7.01,12.02,10]nonadeca-9,12-diene, respectively, was accomplished in high yields. A possibility for the selective transformation of compound
1 to 1-allyl-9-(pent-4-enyl)cyclonon-1-ene and 10-hydroxybicyclo[7.3.01,9]dodec-8-ene in one preparative step was demonstrated.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2156–2159, November, 2007. 相似文献
69.
J. Šesták D. Sedmidubsky G. Moiseev 《Journal of Thermal Analysis and Calorimetry》1997,48(5):1105-1122
Thermochemical and thermodynamical properties of HTSC phases are reviewed for the Y-Ba-Cu-O system and also presented for the newly calculated Bi-Sr-Cu-O system stressing out stoichiometric and phenomenological viewpoints. Simulated data are listed for (H
298
o
-H
o
o
, phase transformation temperatures, standard entropies, standard enthalpies of formation, heat capacities in crystalline phase, etc. Pseudobinary phase diagrams are treated showing the effect of oxygen partial pressure particularly illustrated on the (Sr, Bi, Ba)-Cu-O system.The work was carried out under the project No. A 2010532 supported by the Grant Agency of Academy of Sciences of the Czech Republic and the grant No. 104/97/0589 financed by the Grant Agency of the Czech Republic. 相似文献
70.
T. Tsanov K. Vassilev R. Stamenova C. Tsvetanov 《Journal of polymer science. Part A, Polymer chemistry》1995,33(15):2623-2628
Radiation crosslinked poly(ethylene oxide)s (PEO) modified with two tetraalkylammonium salts: allyldimethyldodecylammonium bromide and ethylmethacrylate dimethyldodecylammonium bromide were prepared. They have been characterized by elemental analysis, IR, 1H-NMR spectra, and DSC measurements. Their activity as phase transfer catalysts (PTC) in the model displacement reaction of 1-bromooctane with aqueous sodium cyanide were studied. The reaction kinetics were followed under pseudo-first-order conditions. Small amounts of onium salt inserted into the PEO network gave rise to a five time increase in the rate constant. The recovered catalysts could be re-used without loss of activity. © 1995 John Wiley & Sons, Inc. 相似文献