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201.
K. Kasazaki K. Yasukawa H. Sano K. Yamada H. Utsumi 《Applied magnetic resonance》2003,23(3-4):585-595
In order to analyze free radical reactions in living stomach, we developed a noninvasive measurement by an in vivo electron spin resonance (ESR) and spin probe technique and applied it to mucosal injury. NH4OH-induced gastric lesions were prepared in rats. A nitroxyl probe was administered intragastrically or intravenously, and then in vivo ESR spectra of the gastric region were obtained by 300 MHz ESR spectroscopy. The signal of the intragastrically administered spin probe decreased gradually and the decay significantly enhanced 30 min after NH4OH administration. The enhanced signal decay was attributed to the OH radical generation, since it was completely suppressed by mannitol, catalase, and desferrioxamine. Two commercially available antigastric lesion drugs, rebamipide and taurine, were tested with a NH4OH-induced gastric lesion model. Both intraperitoneal administration of rebamipide and intravenous administration of taurine suppressed gastric lesion formation induced by NH4OH in a dose-dependent manner. Intraperitoneal preadministration of rebamipide also suppressed the enhanced signal decay, but neither pre- nor coadministration of taurine showed any effect on the enhanced signal decay. The results strongly indicate that the inhibitory mechanism on gastric lesion formation in NH4OH-treated rats is quite different for the two antigastric lesion drugs rebamipide and taurine. 相似文献
202.
Naoko Asakuma Hiroshi Hirashima Hiroaki Imai Toshimi Fukui Motoyuki Toki 《Journal of Sol-Gel Science and Technology》2003,26(1-3):181-184
Structural changes in sol-gel films with photo-irradiation were investigated using zinc oxide (ZnO) derived from zinc acetate. The exposure of the films to an ultraviolet lamp induced hexagonal ZnO crystals in a relatively dense amorphous structure. On the other hand, the formation of zinc metal was found in a porous gel film. The photo-induced crystallization and reduction are ascribed to the electronic excitation in the metastable non-crystalline states. 相似文献
203.
The method is based on a fluorescence reaction of the epoxy group with nicotinamide and 3-acetylpyridine. Oleandomycin phosphate and triacetyloleandomycin can be determined in the ranges 1–80 μg ml?1and 5–80 μg ml?1, respectively, with relative standard deviations of 3–5%. The method can be applied to pharmaceutical preparations. Results obtained by this method and by bioassay in an examination of residual potency agreed well when degradation was done under neutral or alkaline conditions. 相似文献
204.
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206.
The production of double- hypernuclei was studied regarding three different mechanisms: (1) coalescence of a nuclear fragment from peripheral collisions and two A particles, (2) coalescence of two A particles, neutrons and protons due to central collisions, and (3) conversion of a hypernucleus. The production probability is estimated for several projectile-target combinations at 5 and 14.5 GeV/nucleon. 相似文献
207.
208.
Satoru Nakashima Tsuneo Koura Motomi Katada Hirotoshi Sano Izumi Motoyama 《Hyperfine Interactions》1990,53(1-4):361-366
TCNQ salts of 1-monoalkylbiferrocenes showed a temperature-independent trapped-valence state as expected for the unsymmetrical structure of cations. On the other hand, mixed crystals of 1-monobutyl- and 1.1-dibutylbiferrocenium+(TCNQ)
3
–
showed a temperature dependence of the mixed-valence states, showing that the lattice affects the mixed-valence states. 相似文献
209.
Kawasaki T Ogawa A Terashima R Saheki T Ban N Sekiguchi H Sakaguchi KE Sakamoto M 《The Journal of organic chemistry》2005,70(8):2957-2966
Hexahydropyrrolo[2,3-b]indoles 6 were synthesized in five steps from indolin-3-one 8 by a general and efficient method, in which elements of molecular diversity were readily added onto the 3a-position of the pyrrolo[2,3-b]indole ring system. Horner-Wadsworth-Emmons reaction of 2-allyloxyindolin-3-ones 7, derived from indolin-3-one 8 and a variety of allylic alcohols, smoothly proceeded with successive Claisen rearrangement to give the corresponding 3-allyl-3-cyanomethylindolin-2-ones 15. Indolin-2-ones 15 were converted into pyrrolo[2,3-b]indoles 6 using partial hydrolysis followed by reductive cyclization with LiAlH(4). Synthesis of N-methylated pyrrolo[2,3-b]indole derivatives 23 and 26 is also described. 相似文献
210.
It has been known that simply mixing single-walled carbon nanotubes (SWCNTs) in an aqueous solution of gelatin disperses SWCNTs well for a period of months. Gels made from the gelatin-SWCNT mixture are also stable and have a clear, black color. Scanning electron microscopy shows that gelatin molecules self-organize into a foamlike structure. All SWCNTs are embedded in the gelatin film that makes up the foam walls. Those SWCNTs belonging to one face of the foam cell cannot approach other faces to make van der Waals contact. Thus, the foam structure is associated with stabilization of the SWCNT dispersion. The gelatin can be removed thermally while maintaining the foam structure to give a sponge made of nanotube foams. This highly porous solid is electrically conducting and mechanically stable and can be used as a structural frame for composite materials. 相似文献