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61.
The SHG coefficient of a proton-exchanged layer of LiNbO/sub 3/, relative to the bulk value, has been measured for the first time by non-phase-matched SHG using a grating sample. It was found that the d/sub 33/ coefficient is reduced to approximately 0.5 of the bulk value by proton exchanging in pure benzoic acid.<> 相似文献
62.
Kanazawa H Tsubayashi A Nagata Y Matsushima Y Mori C Kizu J Higaki M 《Journal of chromatography. A》2002,950(1-2):303-308
The chiral separation of loxoprofen was achieved on a chiral column with UV and circular dichroism (CD) detection. The good resolution of four loxoprofen stereoisomers was obtained. The column used for the chiral separation was Chiralcel OJ column (250 x 4.6 mm) using hexane-2-propanol-trifluoroacetic acid (95:5:0.1), as an eluent. The flow-rate was 1.0 ml/min and the detection was at 225 nm. In addition, CD and UV spectra were obtained by stopped flow scanning. The method allows the determination of the stereoisomers of loxoprofen in human plasma after the administration of therapeutic dose of the racemic drug, thus HPLC with CD detector is useful for the stereospecific determination of loxoprofen products in biological samples. 相似文献
63.
Kitamura Y Ihara T Okada K Tsujimura Y Shirasaka Y Tazaki M Jyo A 《Chemical communications (Cambridge, England)》2005,(36):4523-4525
The complex [Ru(phen)(2)(dppz)](2+)(phen = 1,10-phenanthroline, dppz = dipyrido[3,2-aratio2',3'-c]phenazine) was attached to the 5' end of a short oligonucleotide to form conjugates, the Delta-isomer of which showed a high cooperativity during the recognition of the repetitive sequence, while the Lambda-isomer did not. 相似文献
64.
65.
Yamada Y Akiba A Arima S Okada C Yoshida K Itou F Kai T Satou T Takeda K Harigaya Y 《Chemical & pharmaceutical bulletin》2005,53(10):1277-1290
This paper concerns a synthetic study of the right-hand segment of complestatin, an inhibitor of gp120-CD4 receptor. The effective synthesis of four important precursors for the right-hand segment of complestatin is described. Two of them are the precursor tripeptides for macrolactamization to the right-hand segment of complestatin at the last step and the other two are the precursor tripeptides for ring-closing reaction using Suzuki and Stille coupling, respectively, to the right-hand segment of complestatin at the last step. These compounds and the synthetic procedure will serve for both the synthesis of the right-hand segment and total synthesis of complestatin in the near future. In addition, consideration of the smooth acidic isomerization of complestatin to chloropeptin was carried out by density functional theory (DFT) calculation. 相似文献
66.
Tetsuya Okunaka Harubumi Kato Katsuo Aizawa Takuzo Ohtani Hirofumi Kawabe Takayuki Asahara Hitoshi Nakajima Ikuhiro Yamasawa Chiharu Ibukiyama Susumu O'Hata Yoshihiro Hayata 《Photochemistry and photobiology》1987,46(5):769-775
Abstract A new diagnostic and therapeutic endoscopic system consisting of an excimer pulse dye laser is presented. This report demonstrates the accumulation of hematoporphyrin derivative (HpD) in atheroma as shown by the fluorescence of HpD using this equipment. Atheroma was induced in the aorta of WHHL (Watanabe heritable hyperlipidemic) rabbits, 5 mg kg−1 HpD was injected intravenously and the rabbits were sacrificed 24 h later. The aorta was dissected and the localization of HpD was examined. Characteristic peaks of the fluorescence of HpD at 630, 665 and 690 nm wavelength were detected in the atheromatous lesion. However, in the fatty plaque, the emission peak at 630 nm was lower and the 665 nm peak faded away. No fluorescence with peaks was detected in the normal area. The ratio of fluorescence intensity in atheroma, border zones and normal areas was 10.4 : 5.0 : 1.0. On normal rabbits made atherosclerotic by diet and balloon damage, an ultra thin endoscopic catheter was inserted from the descending aorta of atherosclerotic rabbits under anesthesia. Essentially the same data was obtained by these studies in vivo as was obtained in the in vitro studies. The above data suggests the possibility of future applications of this equipment for diagnosis of atheroma. 相似文献
67.
Kenichiro Arai Yoshitaka Ogiwara Chiharu Kuwabara 《Journal of polymer science. Part A, Polymer chemistry》1981,19(8):1885-1889
Hydrolysis of dextrin in the presence of copoly(vinyl alcohol-styrenesulfonic acid) resin was investigated kinetically. The hydrolysis rate increased nearly proportionally with increases in the concentrations of the substrate and the catalyst copolymer. This is in contrast to the results found in a similar homogeneous reaction in the presence of soluble copoly(vinyl alcohol–styrenesulfonic acid) in which the reaction rate clearly followed Michaelis–Menten type kinetics. However, the hydrolysis was inhibited by the addition of copoly(vinyl alcohol–styrene) resin or poly(vinyl alcohol). Activation parameters of the hydrolysis in the presence of the copolymer resin as catalyst were also investigated, and it was found that the enthalpy and entropy of the activation in the presence of the copolymer resin were lower than those in Amberlite 120B and slightly decreased when vinyl alcohol unit was introduced. From these results it was concluded that the poly(vinyl alcohol) sequence introduced into the insoluble catalyst copolymer resin also played an important part in the acceleration of dextrin hydrolysis in a manner similar to the case of a soluble catalyst, although the interaction with the substrate was weaker. 相似文献
68.
Junichi Motohisa Chiharu Tazaki Tomoki Irisawa Masashi Akabori Takashi Fukui 《Journal of Electronic Materials》2000,29(1):140-145
We investigated the delta-doping (δ-doping) of Si using SiH4 on MOVPE-grown GaAs (001) vicinal surfaces to explore the possibility of selective incorporation of Si along atomic steps,
and to demonstrate doping quantum wires by the combination of multiatomic steps and wire-like doping. It was found that the
doping density on vicinal surfaces was enhanced as the misorientation angle was increased, which suggested the enhanced decomposition
of SiH4 and the selective incorporation of Si at step edges. It was also found that this selective incorporation could be enhanced
by annealing the surface prior to the δ-doping, which resulted from the reduced incorporation of Si at the terrace regions.
Anisotropic electron transport properties which are expected from the wire-like incorporation along step edges are also discussed. 相似文献
69.
Yamada Y Arima S Okada C Akiba A Kai T Harigaya Y 《Chemical & pharmaceutical bulletin》2006,54(6):788-794
7-Substituted (Cl, Br, I) indoles were synthesized by using thallation of N-formylindoline as a key reaction. Two precursor tripeptides for the right-hand segment of chloropeptin were synthesized by using (R)-7'-iodo and 7'-bromotryptophans derived from each 7-substituted indole (I, Br) obtained by the above procedure. 相似文献
70.
In order to indentity the corrosion products formed on steel surfaces from 57Fe Mössbauer spectroscopy, detailed Mössbauer parameters have been determined for various kinds of iron-oxyhydroxides: -FeOOH, -FeOOH, -FeOOH and -FeOOH. 57Fe Mössbauer measurements of the iron oxyhydroxides indicate the following results. Fe occupies a single site in -FeOOH, but below the Néel temperature as at e.g., 300 K the Mössbauer spectrum is always broad, showing a distribution of the strength of the magnetic exchange interactions. Its shape depends on the grain-size and synthetic methods of the specimen. Fe occupies 3 sites in -FeOOH. High-purity reagents of -FeOOH always contain small amounts of -FeOOH and their Néel temperatures depend on the synthetic methods of the specimen. Mössbauer spectroscopy of the synthetic -FeOOH shows very broad distribution of the hyperfine magnetic fields. 相似文献