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71.
6-Bromoacetoxyandrostenediones (1 and 2) and 17 beta-bromoacetoxy-4-androsten-3-one having a 6 beta-bromo (3), 6-keto (4), or 6 beta-methoxyl (5) substituent were evaluated as mechanism-based inactivators of human placental aromatase. All of these compounds except the 6 alpha-bromoacetate 1 showed a time-dependent, pseudo-first-order inactivation of aromatase in the presence of reduced nicotinamide adenine dinucleotide phosphate (NADPH) with apparent Ki's of 40, 50, 30, and 34 microM and kinact's of 0.048, 0.364, 0.267, and 0.040 min-1, respectively, for compounds 2, 3, 4, and 5. The enzyme inactivation with compounds 3 and 4 was blocked by the addition of the substrate androstenedione to the incubates, and NADPH and oxygen were required for their effective time-dependent inactivation. 相似文献
72.
A novel ring tansfer reaction of furans to fused furans by tandem intramolecular Diels-Alder reaction and base-catalyzed ring-opening of the adducts has been developed. 相似文献
73.
Kimura M Ueki H Ohta K Hanabusa K Shirai H Kobayashi N 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(20):4954-4959
Atom-transfer radical polymerization (ATRP) of acrylates from the initiator-modified zinc phthalocyanine yielded amphiphilic, phthalocyanine-terminated polymers with a narrow molecular-weight distribution. The disklike phthalocyanine moiety was incorporated into one end of the polymer chain. We investigated the aggregation behavior of phthalocyanine-terminated polymers in solution and in the solid state by using UV-visible, FT-IR, differential scanning calorimetry (DSC), and temperature-controlled powder X-ray diffraction (XRD) measurements. Amphiphilic phthalocaynine-terminated polymers that possess a poly[tri(ethylene glycol)methyl ether acrylate] chain aggregate in methanol to form a physical gel. Images from atomic force microscopy (AFM) and transmission electron microscopy (TEM) indicate that the physical gel contains a dense fibrous network structure, in which the zinc phthalocyanine groups were stacked into one-dimensional columnar aggregates through intermolecular pi-pi interactions between the pi-conjugated phthalocyanines and through van der Waals interaction of alkyl chains. 相似文献
74.
Experimental study of color degree of freedom of gluons in e+e- annihilation at sqrt s around 60 GeV
Abe K Amako K Arai Y Asano Y Chiba M Chiba Y Daigo M Emura T Fukawa M Fukui T Fukushima Y Haba J Hemmi Y Higuchi M Hirose T Hojyo Y Homma Y Hoshi Y Ikegami Y Ishihara N Kamitani T Kanematsu N Kanzaki J Kikuchi R Kondo T Korhonen TT Koseki T Kurashige H Matsui T Minami M Miyake K Mori S Nagashima Y Nakamura T Nakano I Narita Y Odaka S Ogawa K Ohama T Ohsugi T Okamoto A Ono A Oyama T Sakamoto H Sakuda M Sasao N Sato M Shioden M Shirai J Shirakata M Sugimoto S Sumiyoshi T Suzuki A Suzuki Y 《Physical review letters》1991,66(3):280-284
75.
Katsuhiro Sumi Mutsumi Kimura Isei Nakamura 《Journal of polymer science. Part A, Polymer chemistry》1994,32(7):1243-1254
A vinyl monomer containing the pendant tetraphenylporphyrin (TPP) group, 4-vinyltetraphenylporphyrin (VTPP), was synthesized. A homopolymer (PVTPP) which is insoluble in water, and three water-soluble polymers were obtained by radical polymerization. The water-soluble polymers are two anionic polymers (PVPTSPP and PVTPP-StSO3) and a cationic polymer (PVTPP-VPyM). PVPTSPP has sulfonic acid groups in a TPP group and very high charge density. PVTPP-StSO3 was obtained by copolymerization of VTPP and sodium 4-styrenesulfonate. PVTPP-VPyM was obtained by quarternarization of a copolymer of VTPP and 4-vinylpyridine. Polymeric manganese(III) complexes (PMn-VTPP, PMnVPTSPP, PMnVTPP-StSO3, and PMnVTPP-VPyM) were prepared from the polymers and manganese acetate. The acetate ligand in PMnVTPP can be easily substituted by another ligand such as Cl?, AcO?, OH?, and SCN?. The substitution reaction occurs in the interface between water and chloroform. The sulfonated homopolymer, PMnVPTSPP, cannot incorporate with anionic ligands because of the strong electrostatic repulsion. In the anionic copolymer, PMnVTPP-StSO3, the ligand substitution reaction with SCN ligand needs activation energy of 53 kJ/mol. In the cationic polymer complex, PMnVTPP-VPyM, the OH ligand can be easily substituted with the SCN ligand and the equilibrium constant of the reaction was estimated at 1.38 × 10?3. © 1994 John Wiley & Sons, Inc. 相似文献
76.
Kondo H Kanematsu M Itoh K Ito K Maetani Y Goshima S Matsuo M Matsunaga N Konishi J Hoshi H Moriyama N 《Magnetic resonance imaging》2005,23(1):89-95
The purpose of our study was to determine whether or not the addition of T2-weighted fast spin-echo (SE) imaging to gadolinium-enhanced spoiled gradient-recalled-echo (GRE) imaging improves the observer performance in the preoperative detection of malignant hepatic tumors. Gadolinium-enhanced GRE and fat-suppressed T2-weighted fast SE images obtained in 49 patients with 82 surgically confirmed malignant hepatic tumors (40 hepatocellular carcinomas and 42 metastases) were retrospectively reviewed by three independent off-site observers. In the random review of images, gadolinium-enhanced GRE images were reviewed first; thereafter, T2-weighted fast SE images were added for combined review. Observer performance was evaluated with the McNemar's test and receiver operating characteristic curve analysis. For gadolinium-enhanced GRE images alone vs. combined images, sensitivities for detection were 78% vs. 79% for hepatocellular carcinomas (P>.05), 67% vs. 71% for metastases (P<.05) and 72% vs. 75% for tumors overall (P<.05), respectively. The Az values were 0.892 vs. 0.889 in hepatocellular carcinomas (P>.05), 0.797 vs. 0.828 in metastases (P<.05) and 0.839 vs. 0.846 in tumors overall (P>.05), respectively. Our results showed that the addition of T2-weighted fast SE imaging to gadolinium-enhanced GRE imaging improved the observer performance in the detection of metastases. 相似文献
77.
78.
Noriko Hata Kaoru Teraguchi Mutsumi Yamaguchi Issei Kasahara Shigeru Taguchi Katsumi Goto 《Mikrochimica acta》1992,106(1-2):101-108
Ammonia-nitrogen, in the range 0.06 to 2 g in 20 ml of water sample, is treated with hypochlorite and thymol to form an intensely blue anionic dye called indothymol. The indothymol is collected on a glass-fiber filter as the ion-pair with benzyldimethyltetradecylammonium ion. The indothymol collected on the filter is dissolved in a small volume of dimethylformamide (DMF) and the absorbance due to the indothymol is measured at 675 nm against the reagent blank. An unexpectedly high sensitivity was obtained because of the increased molar absorptivity of indothymol in DMF (3.2 × 104 l mol–1 cm–1, max = 675 nm), approximately 3 times larger than that in water (1.16 × 104 l mol–1 cm–1, max = 660 nm). The detection limit, defined as three times the standard deviation of the blank, is better than 1 g 1–1 of ammonia-nitrogen with 5-fold preconcentration. 相似文献
79.
80.
Determination of acrolein in serum by high‐performance liquid chromatography with fluorescence detection after pre‐column fluorogenic derivatization using 1,2‐diamino‐4,5‐dimethoxybenzene
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Takahiro Imazato Mariko Kanematsu Naoya Kishikawa Kaname Ohyama Takako Hino Yukitaka Ueki Eisuke Maehata Naotaka Kuroda 《Biomedical chromatography : BMC》2015,29(9):1304-1308
Acrolein is a major unsaturated aldehyde that is generated during the lipid peroxidation process. The measurement of acrolein in biological samples should be useful to estimate the degree of lipid peroxidation and to evaluate the effect of hazardous properties of acrolein on human health. In this study, a highly sensitive and selective high‐performance liquid chromatography with fluorescence detection method was developed for the determination of acrolein in human serum. The proposed method involves the pre‐column fluorogenic derivatization of acrolein with 1,2‐diamino‐4,5‐dimethoxybenzene (DDB) as a reagent. The fluorescent derivative of acrolein could be detected clearly without any interfering reagent blank peaks because DDB does not have intrinsic fluorescence itself, and the detection limit was 10 nM (signal‐to‐noise ratio = 3). The proposed method could selectively detect acrolein in human serum with a simple protein precipitation treatment. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献