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991.
Ishibashi K Tsue H Sakai N Tokita S Matsui K Yamauchi J Tamura R 《Chemical communications (Cambridge, England)》2008,(24):2812-2814
Electron paramagnetic resonance spectroscopy has unmasked for the first time the spin-delocalised doublet- and triplet-ground states of azacalix[4]arene cation radicals. 相似文献
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994.
We have compared endo- and exo-type protease reactions and characterized the enzymatic reaction mechanisms by determining all kinetic parameters (k(on), k(off), k(cat), K(d) = k(off)/k(on), and K(m) = (k(off) + k(cat))/k(on)) by following the mass change of the formation and the decay of the enzyme-substrate (ES) complex (k(on) and k(off)), and the formation of the product (k(cat)) on a 27 MHz quartz-crystal microbalance in aqueous solutions. The K(m) value was nearly equal to the K(d) value for the endo-type protease (subtilisin and alpha-chymotrypsin); however, in the case of exo-type protease (carboxypeptidase P), the K(m) value was quite different from the K(d) value, due to k(cat) > k(off). 相似文献
995.
The binding of amino acids to water-soluble zinc porphyrins in basic aqueous solution was spectrophotometrically analyzed. The amino acids were bound to the porphyrins through the coordination of the N atom with the central zinc ion. Additional attractions arise due to Coulomb interactions between the -COO(-) anion of the amino acids and the -N(CH(3))(3)(+) cation of the porphyrin substituents and due to hydrophobic interactions between the porphyrin plane and the hydrophobic substituents of the amino acids. These attractions could be explained based on the binding data. The compensatory relationships of DeltaS and DeltaH were also discussed. 相似文献
996.
Kimura T Kanota N Matsui K Tanaka I Tsuboi T Takaguchi Y Yomogita A Wakahara T Kuwahara S Nagatsugi F Akasaka T 《Inorganic chemistry》2008,47(9):3577-3583
4,5-Bis(benzylthio)-3,6-diethylphthalonitrile (1) was mixed with 4 -t-butylphthalonitrile and then treated with lithium alkoxide in n-hexanol to produce the corresponding unsymmetrically substituted phthalocyanines (2) and (3) with two or four benzylthio groups, respectively. Treatment of phthalocyanine (2) with nickel(II) acetate yielded the corresponding metal complex 2-Ni. Two benzyl groups of 2 and 2-Ni were removed with lithium/THF/ammonia at -78 degrees C under argon, and the dithiolate anions generated were then reacted with elemental sulfur to give monotrithiolophthalocyanines (5) and (5-Ni). A similar treatment of 3 produced bistrithiolophthalocyanine (6). Tetrakistrithiolophthalocyanine (7-Ni) was prepared by complexation of phthalocyanine (4) with nickel(II) acetate, followed by a Birch reduction of the resulting nickel(II) complex (4-Ni), and then sulfurization and cyclization of the octathiolate anions that were generated. The structures of the phthalocyanines were determined by (1)H NMR and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The optical and electrochemical properties of the phthalocyanines were examined by UV-vis absorption spectroscopy and cyclic voltammetry. Treatment of 5, 5-Ni, 6, 7, and 7-Ni with trifluoroacetic acid in chloroform generated positively charged species, which were characterized by UV-vis and/or NMR spectroscopy. 相似文献
997.
Funabiki K Shibata A Iwata H Hatano K Kubota Y Komura K Ebihara M Matsui M 《The Journal of organic chemistry》2008,73(12):4694-4697
Reduction of the obtained chiral (S)- tert-butyl 2-(perfluoroalkanoyl)pyrrolidine-1-carboxylate with sodium borohydride or lithium aluminum hydride proceeded smoothly to give the corresponding (S)- tert-butyl 2-((R)-perfluoro-1-hydroxyalkyl)pyrrolidine-1-carboxylate in yields of 73-97% with excellent diastereoselectivities (up to >98% de), compared with the reduction of nonfluorinated (S)-tert-butyl 2-pentanoylpyrrolidine-1-carboxylate. 相似文献
998.
Pearson’s Chi-square statistic for frequency tables depends on what is hypothesized as the expected frequencies. Its partitions also depend on the hypothesis. Lancaster (J R Stat Soc B 13:242–249, 1951) proposed ANOVA-like partitions of Pearson’s statistic under several representative hypotheses about the expected frequencies. His expositions were, however, not entirely clear. In this paper, we clarify his method of derivations, and extend it to more general situations. A comparison is made with analogous decompositions of the log likelihood ratio statistic associated with log-linear analysis of contingency tables. 相似文献
999.
Remarkable Charge Separation and Photocatalytic Efficiency Enhancement through Interconnection of TiO2 Nanoparticles by Hydrothermal Treatment
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Prof. Yusuke Ide Nozomu Inami Hideya Hattori Kanji Saito Dr. Minoru Sohmiya Prof. Nao Tsunoji Prof. Kenji Komaguchi Prof. Tsuneji Sano Prof. Yoshio Bando Prof. Dmitri Golberg Prof. Yoshiyuki Sugahara 《Angewandte Chemie (International ed. in English)》2016,55(11):3600-3605
Although tremendous effort has been directed to synthesizing advanced TiO2, it remains difficult to obtain TiO2 exhibiting a photocatalytic efficiency higher than that of P25, a benchmark photocatalyst. P25 is composed of anatase, rutile, and amorphous TiO2 particles, and photoexcited electron transfer and subsequent charge separation at the anatase–rutile particle interfaces explain its high photocatalytic efficiency. Herein, we report on a facile and rational hydrothermal treatment of P25 to selectively convert the amorphous component into crystalline TiO2, which is deposited between the original anatase and rutile particles to increase the particle interfaces and thus enhance charge separation. This process produces a new TiO2 exhibiting a considerably enhanced photocatalytic efficiency. This method of synthesizing this TiO2, inspired by a recently burgeoning zeolite design, promises to make TiO2 applications more feasible and effective. 相似文献
1000.
Single‐step enrichment of basophils from human peripheral blood by a novel method using a Percoll density gradient
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Hiroyuki Shiono Takuya Matsui Tadashi Okada Yoichiro Ito 《Journal of separation science》2016,39(15):3062-3071
We have developed a novel continuous flow‐through cell separation method using a Percoll density gradient. This method can continuously separate a large number of cells into five fractions according to their densities. To apply this method to the separation of basophils, Percoll density gradients were modified to improve basophil enrichment. When a set of Percoll density gradients was prepared (1.071, 1.075, 1.080, 1.084, and 1.090 g/mL) the basophils in a healthy volunteer were enriched by an average of 23.1 and 63.5% at Percoll densities of 1.075 (fraction 3) and 1.080 g/mL (fraction 4), respectively. On average, the yield of basophils was 1.66 × 105 cells in fraction 3 and 1.61 × 105 cells in fraction 4 from 9 mL of peripheral blood. The expression of CD203c (cluster of differentiation 203c) on separated basophils was upregulated by anti‐immunoglobulin E stimulation similar to basophils in whole blood. Histamine release induced by calcium ionophore was also observed in the separated basophils. The present method will be useful for basophil enrichment since it preserves their function without using counterflow elutriation and immunological reagents, and this method will be effective as a preparative separation for cell purification by flow cytometry. 相似文献