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81.
82.
S. Kulprecha T. Nihira C. Shimomura K. Yamada N. Nilubol T. Yoshida H. Taguchi 《Tetrahedron》1984,40(15):2843-2846
The microbiological transformation of lithocholic acid (3α-hydroxy-5β-cholanic acid) into 3α, 15β-dihydroxy-5β-cholanic acid by Cunninghamella sp. is Investigated. The structure has been determined on the basis of two-dimensional 1H-NMR. 相似文献
83.
G. Tamai H. Yoshida H. Imai T. Takashina K. Kotoo T. Fuwa Y. Tsuchioka H. Matsuura G. Kajiyama 《Chromatographia》1985,20(11):671-676
Summary New quinidine metabolites, including 10,11-dihydrodiol quinidine N-oxide, 10,11-dihydrodiol quinidine and their glucuronides, were found in human urine. A quinidine monitoring HPLC method including these metabolites, is proposed by the direct injection of body fluid samples onto the precolumn for deproteinization followed by reverse phase separation in the analytical column with a column switching technique. The recovery of spiked quinidine and its metabolites in plasma was quantitative (98–102%) with good reproducibility (C.V.: 1.6–4.0%). Several clinical samples such as whole blood and urine were analyzed by the present method. 相似文献
84.
Qi ZM Matsuda N Santos J Yoshida T Takatsu A Kato K 《Journal of colloid and interface science》2004,271(1):249-253
Broadband, time-resolved optical waveguide (OWG) spectroscopy has been used for in situ, real-time investigation into the self-assembly of metal nanoparticle monolayers. The OWG spectroscopy makes it possible to use the transverse electric (TE) and transverse magnetic (TM) modes to measure surface plasmon absorption of immobilized metal nanoparticles in two directions, parallel and normal to the waveguide surface. Therefore, this technique can provide direction-dependent information on the metal nanoparticles at the interface. In this paper, a 50-microm-thick glass plate was used as a slab waveguide and the kinetics of Au nanoparticle adsorption on a hemoglobin-functionalized glass substrate was examined in the early stage of self-assembly. The findings show that with the TE mode the surface plasmon resonance (SPR) behavior for immobilized Au nanoparticles is different from that with the TM mode. 相似文献
85.
86.
A new pulse sequence is proposed for the determination of scalar coupling correlation in small- and medium-sized organic compounds. The method uses a combination of the double pulsed field gradient spin-echo (DPFGSE) and the selective population transfer (SPT) techniques and is shown to be useful in the analysis of complex spectra with many overlapped signals. The usefulness of this method in the structural elucidation of natural substances is demonstrated using strychnine and digitoxin as examples. 相似文献
87.
Takuma Shinya Nakashima Noriyuki Tantirungkij Manee Kinoshita Shinichi Okada Hirosuke Sew TatsÜji Yoshida Toshiomi 《Applied biochemistry and biotechnology》1991,28(1):327-340
Applied Biochemistry and Biotechnology - A NADPH/NADH-dependent xylose reductase gene was isolated from the xylose-assimilating yeast,Pichia stipitis. DNA sequence analysis showed that the gene... 相似文献
88.
Funyu S Isobe T Takagi S Tryk DA Inoue H 《Journal of the American Chemical Society》2003,125(19):5734-5740
Visible light irradiation of a reaction mixture of carbonyl-coordinated tetra(2,4,6-trimethyl)phenylporphyrinatoruthenium(II) (Ru(II)TMP(CO)) as a photosensitizer, hexachloroplatinate(IV) as an electron acceptor, and an alkene in alkaline aqueous acetonitrile induces selective epoxidation of the alkene with high quantum yield (Phi = 0.6, selectivity = 94.4% for cyclohexene and Phi = 0.4, selectivity = 99.7% for norbornene) under degassed conditions. The oxygen atom of the epoxide was confirmed to come from a water molecule by an experiment with H(2)(18)O. cis-Stilbene was converted into its epoxide, cis-stilbeneoxide, without forming trans-stilbeneoxide. trans-Stilbene, however, did not exhibit any reactivity. Under neutral conditions, an efficient buildup of the cation radical of Ru(II)TMP(CO) was observed at the early stage of the photoreaction, while an addition of hydroxide ion caused a rapid reaction with the cation radical to promote the reaction with reversion to the starting Ru(II)TMP(CO). A possible involvement of a higher oxidized state of Ru such as Ru(IV), Ru(V), Ru(VI) through a dismutation of the Ru(III) species was excluded by an experiment with Ru(VI)TMP(O)(2). Decarbonylation of the Ru complex was also proven to be invalid. A reaction mechanism involving an electron transfer from the excited triplet state of Ru(II)TMP(CO) to hexachloroplatinate(IV) and subsequent formation of OH(-)-coordinated Ru(III) species, leading to an oxo-ruthenium complex as the key intermediate of the photochemical epoxidation, was postulated. 相似文献
89.
A phytochemical investigation in plantlets of the Brazilian medicinal tree Virola surinamensis resulted in the isolation and structural determination of four new compounds: 3-hydroxy-4-methyl-2-(11'-piperonyl-n-undecyl)-butenolide; 3-hydroxy-4-methyl-2-(7'-piperonyl-n-heptyl)-butanolide; 9'-(3,4-methylenedioxy-phenyl)-nonanoic acid and 13'-(3,4-methylene-dioxyphenyl)-tridecanoic acid. Thirteen compounds previously isolated from seeds and adult plants were also reported. 相似文献
90.
Wesley Y. Yoshida Kit K. Lee Anthony R. Carroll Paul J. Scheuer 《Helvetica chimica acta》1992,75(5):1721-1725
Two cytotoxic triphenylpyrrolo-oxazinones were isolated from a tunicate and their structures elucidated by spectral methods. Lukianol A ( = 3,7,8-tris(4-hydroxyphenyl)pyrrolo[2,1-c][1,4]oxazin-1 (1H)-one; 1 ) had MIC of 1 μg/ml in KB cytotoxicity tests; MIC value for 2 was 100 μg/ml. 相似文献