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71.
Takenori Tomohiro Kouichi Uoto Hiroaki Okuno 《Journal of heterocyclic chemistry》1990,27(5):1233-1239
A series of macrocyclic tetraamines with 28-, 32-, 36-, 40- and 44-membered rings have been efficiently prepared from the corresponding ditosylamide and monobromoalcohol derivatives in 6 steps via a double condensation reaction. Overall yields were: 41, 41, 46, 29, and 33%, respectively, for 1,8,15,22-tetraazacyclooctacontane ( 11a ), 1,9,17,25-tetraazacyclodotriacontane ( 11b ), 1,10,19,28-tetraazacyclohexatriacontane ( 11c ), 1,11,21,31-tetraazacyclotetracontane ( 11d ) and 1,12,23,34-tetraazacyclotetratetracontane ( 11e ). 相似文献
72.
Yoshihisa Kurasawa Yoshihisa Okamoto Atsushi Takada 《Journal of heterocyclic chemistry》1985,22(3):935-936
Novel compounds 8-(quinoxalin-2-yl)-1,2,4-triazolo[3,4-f][1,2,4]triazines 3a,b were obtained by a new annulation method in the 1,2,4-triazine synthesis. 相似文献
73.
Tetsuro Kawahara Kazuhiro Doushita Hiroaki Tada 《Journal of Sol-Gel Science and Technology》2003,27(3):301-307
Anatase TiO2 films (thickness = 50 nm) were formed in shape of stripes (width = 1.6 mm, interval = 0.4 mm) by gravure printing on commercially available SnO2 coated soda-lime glass substrates (dimension = 300 × 300 mm). Its photocatalytic activity was examined for the gas-phase oxidation of CH3CHO in comparison with a simple TiO2 photocatalyst formed on a silica glass. The patterned TiO2/SnO2 bilayer type photocatalyst showed a high photocatalytic activity in an H2O bearing atmosphere. On the other hand, neither the patterning nor stacking effect was observed for the same reaction under dry conditions. These results could be explained in terms of the reducing potential of the electrons in the conduction band of the SnO2 layer. 相似文献
74.
Yoshihiro Yamauchi Takanori Okamoto Hiroshi Murayama Akira Nagara Tadashi Kashihara 《Applied biochemistry and biotechnology》1995,53(3):277-283
The characteristics of yeast sulfite metabolism in a multistage bioreactor system for beer fermentation were investigated. No sulfite was produced in the continuous stirred-tank reactor (CSTR). However, large amounts were produced in the packed-bed reactor (PBR). Production of sulfite in the PBR seems to be inevitable when it is operated continuously. In order to control the sulfite level in the young beer, the yeast needs to be reactivated into the growth phase. One possible strategy to achieve this is to aerate and periodically remove yeast clogged in the reactor once every 6–7 months before the sulfite level exceeds a given concentration (e.g., 20 mg/L). It was confirmed that sulfite production is closely related to the growth condition of the yeast and is therefore important to consider in the control strategy for sulfite when using the immobilized yeast reactor for beer production. 相似文献
75.
Takeo Fujino Hiroaki Tagawa Takeo Adachi Hiroshi Hashitani 《Analytica chimica acta》1978,98(2):373-383
A simple gravimetric determination of oxygen in uranium oxides and ternary uranium oxides is described. In alkaline earth uranates which are formed by heating in air at 800–1100°C, uranium is in the hexavalent state over certain continuous ranges of alkaline earth-to-uranium ratios. Thus, if an alkaline earth uranate or a compound containing an alkaline earth element, e.g. MgO, is mixed with the oxide sample and heated in air under suitable conditions, oxygen can be determined from the weight change before and after the reaction. The standard deviation of the O:U ratio for a UO2+x test sample is ±0.0008–0.001, if a correction is applied for atmospheric moisture absorbed during mixing. 相似文献
76.
Summary The molecular-shape recognition of polycyclic aromatic hydrocarbons has been studied on various stationary phases in reversed-phase high-performance liquid chromatography. The examined stationary phases were phenyl-, diphenyl-, triphenyl- and benzyl-bonded silicas. The results of regression analysis inidcated that triphenylsilica is the best packing material to recognize the difference in the molecular-shape of structural isomers. This fact was confirmed by the separation of 4-ring isomers. 相似文献
77.
Zeolite T membranes were synthesized on tubular porous mullite tubes by hydrothermal synthesis. The membranes selectively permeated carbon dioxide from CO2/CH4 and CO2/N2 mixtures with high separation performances, which were due to combined effects of molecular sieving and competitive adsorption. 相似文献
78.
79.
A microanalytical method for the determination of traces of natural brassinosteroids as their dansylaminophenylboronates by liquid chromatography with fluorimetric detection is described. The boronates are easily prepared by the reaction of brassinosteroids with dansylaminophenylboronic acid (DABA), which was newly synthesized as a precolumn fluorogenic reagent for brassinosteroids. The potential of the method is demonstrated by the separation of a standard brassinosteroid mixture and the analysis of a biologically active fraction sample obtained from an extract of Zea mays L. pollen. The detection limit of the DABA derivative was found to be 25 pg for brassinolide, which is superior to that of the phenanthreneboronate derivative. 相似文献
80.
Ramaswamy K Saito H Murakami H Shiba K Suga H 《Journal of the American Chemical Society》2004,126(37):11454-11455
Fx3 is an artificial ribozyme with the ability to aminoacylate various tRNAs with phenylalanine and its nonnatural derivatives. Herein we report a simple strategy to build tRNA specificity into the generic Fx3, by appending to its 3'-end a tRNA-specific sequence (TSS), which is complementary to the acceptor stem of the cognate tRNA. This new designer ribozyme, referred to as Fx10, is able to recognize its cognate tRNA via a 10-base-pair interaction that is formed after the invasion of the tRNA acceptor stem by the TSS. We have demonstrated that Fx10 can aminoacylate its cognate tRNA with a high degree of specificity and also discriminate against the noncognate tRNAs. Because the tRNA specificity can be easily programmed into Fx10, it is a custom-made catalyst to generate nonnatural aminoacyl-tRNAs. 相似文献