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991.
Metabolic thermogenic curves of mitochondria isolated from liver tissue of Carassius auratus and the effect of different concentration of NaAsO2 on it were investigated by TAM air isothermal microcalorimeter, ampoule method, at 28.00 ℃. From the thermogenic curves, activity recovery rate constants k, the maximum heat production rate (Pmax) and the total heat produced (Q) were obtained. The values of k and Pmax decline gradually with the increase of the concentration of NaAsO2, and both of the values of Pmax and k are highly correlated to the concentration of NaAsO2. When concentration of NaAsO2 reached 16.0 μg/mL, the maximum heat production rate dropped to 70.8% of the control group, and the corresponding percentage of k was 71.4% of the control group. This experimental result indicates that the addition of NaAsO2 has restrained the metabolic activities of mitochondria in vitro. 相似文献
992.
Christopher KoradinWolfgang Dohle Alain L RodriguezBertram Schmid Paul Knochel 《Tetrahedron》2003,59(9):1571-1587
A general preparation of 2-substituted indoles starting from functionalized 2-alkynylanilines has been developed. This base mediated reaction has also been used to synthesize the heterocyclic core of the marine alkaloid hinckdentine A. Furthermore the reaction was successfully adapted to the solid phase. Benzofurans and isoindolones could also be prepared with this method. 相似文献
993.
B. S. Fedorov N. L. Gotovina V. V. Arakcheeva R. F. Trofimova L. O. Atovmyan 《Russian Chemical Bulletin》1996,45(5):1157-1161
A novel reaction of the sodium salt of 2-nitroethanol in aqueous ammonia resulted in the sodium salt of 2-oxo-3-hydroxypropionic acid oxime (1) has been found. Bromination of1 affords 2-bromo-2-nitropropane-1,3-diol (2) with a previously unknown molecular conformation. The formation mechanisms of compounds1 and2 were suggested. X-ray analysis of products1,2 and that of the model compound, 2,2-dinitropropane-1,3-diol, was performed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1217–1221, May, 1996. 相似文献
994.
The effects of β-cyclodextrin (β-CD) on the spectral properties and electrochemical behaviour of barbitone sodium were studied using electrochemical and optical techniques. The apparent changes in the UV-visible absorption spectrum and fluorescence quenching of the barbiturate upon addition of β-CD afford clear evidence of the inclusion complex formation of β-CD in aqueous solutions. The redox acitivity of barbitone sodium in both the absence and presence of β-CD was assessed by an electrochemical method in 0.05 M potassium nitrate-nitric acid (pH 1.8) solution. While the complexation reaction remains is equilibrium, the apparent formation constant of the inclusion complex could be obtained by either spectral or electrochemical methods. Quantitative evaluation of the data gave 326 l mol−1 under equilibrium conditions at 20°C. Possible conclusions are discussed on the basis of environmental changes around the barbiturate molecules on inclusion. 相似文献
995.
Apparent molar volumes and heat capacities of sodium benzenesulfonate have been measured at 25°C and at molalities up to 1.1 molal using a Picker flow densimeter and a Picker flow heat capacity calorimeter. Data for both properties have been modeled with Pitzer equations for the respective functions, and the standard state values evaluated. The apparent molar volume of sodium benzenesulfonate appears to be relatively insensitive to sample preparation. Possible reasons for the difference in the apparent molar volume reported here and the literature value are discussed. 相似文献
996.
通过等摩尔竞争反应研究了氟化物催化的硅氢化合物和取代酚的脱氢偶联反应机理。研究表明,p-XC6H4OH在反应中的取代基效应与氟化物催化取代苯甲醛p-XC6H4CHO的硅氢化反应中的不同,这表明它们的反应机理存在差异,在这两种反应中,虽然F^-对Si的配位都促进了硅氢化合物中的H对底物中带正电荷原子的亲核进攻,但是在催化酚解反应中,由于没有四中心过渡态的形成,因此下一步取代酚中的氧原子对F^-配位的 相似文献
997.
Díaz V. González Armas A. González Martí C. Ossuna Pérez Pont M. L. 《Mikrochimica acta》1993,111(1-3):113-118
A sensitive, selective Spectrofluorimetric method has been developed for the determination of thiabendazole in a sodium dodecylsulphate micellar medium. The method features a linear determination range of 0.020-15 g and a detection limit of 0.2 ng/ml, with a relative standard deviation of less than 3%. By using a straightforward extraction procedure with ethyl acetate and hydrochloric acid, the method provided average thiabendazole recoveries above 96% from apple, pear and potato samples. 相似文献
998.
A. P. Apisarov V. A. Kryukovskii Yu. P. Zaikov A. A. Red’kin O. Yu. Tkacheva V. A. Khokhlov 《Russian Journal of Electrochemistry》2007,43(8):870-874
Electroconductance of molten electrolytes KF-AlF3 (cryolite ratio 1.3) containing LiF or/and Al2O3 is evaluated using empirical equations. The electroconductivity of molten mixtures KF-AlF3, KF-AlF3-Al2O3, KF-AlF3-LiF, and KF-AlF3-LiF-Al2O3 is measured in the temperature interval 687 to 797°C. The electroconductivity is determined in cells with a capillary of pyrolytic boron nitride and parallel molybdenum electrodes. Comparing calculated and experimental data on the electroconductivity of cryolite-alumina melts confirms that the model proposed for the calculations reflects the temperature and concentration dependences adequately enough and makes it possible to forecast variations in the electroconductivity upon adding different admixtures into the electrolyte. 相似文献
999.
1000.
硫酸铵-碘化钾-乙醇体系萃取分离钯 总被引:3,自引:0,他引:3
传统的萃取分离法主要是采用与水互不相溶的有机溶剂作萃取溶剂,有的反应速度慢,传质速率低,分配比较小而需要在振荡器上进行较长时间振荡或多次萃取才能达到定量萃取的目的。均相萃取、异相分离萃取体系可以克服异相萃取分离技术中的一些缺点而受到重视[1,2]。本文以乙醇为萃取溶剂,均相萃取、异相分离Pd(Ⅱ)。试验表明硫酸铵存在下乙醇与水分相过程中,Pd(Ⅱ)与I-开成的PdI42-与质子化乙醇(C2H5OH2+)形成电中性的缔合物(C2H5OH2+)2·PdI42-被乙醇相萃取,能使Pd(Ⅱ)从Fe(Ⅲ)、Al(Ⅲ)、Zn(Ⅱ)、Mn(Ⅱ)、Ni(Ⅱ)、Cr(Ⅲ)、Co(Ⅱ)… 相似文献