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981.
Akira Sugimoto Takeshi Kotani Junko Tsujimoto Shigeo Yoneda 《Journal of heterocyclic chemistry》1989,26(2):435-438
In order to examine the “capto-dative” substitution-effect on the electrical conductivity, five compounds which have capto-dative substituents were prepared. Electron withdrawing (capto) group was nitro- or cyano-substituted phenyl and electron donating (dative) one was 5-methyl-5,10-dihydrophenazinyl moiety. The character of intramolecular electron donor acceptor complex of the five compounds were demonstrated by their uv spectra. Electron donor acceptor complexes of them with tetracyanoquinodimethane were prepared and their electrical resistivities were measured. 相似文献
982.
SUNBURN CELL: FACTORS INVOLVED IN ITS FORMATION. 总被引:1,自引:0,他引:1
Abstract— The sunburn cell (SC) is a type of individual cell death appearing in epidermis principally after exposure to middle-wavelength UV radiation (UVR). Because SCs can easily be recognized by histologic characteristics, they may provide a countable index of assessment of the degree of UVR injuries. However, despite extensive investigations, the mode of formation of this UVR-induced apoptosis has not fully been understood. In this review article, we are summarizing the results of recent studies with special reference to both the formation mechanisms and their implications in the field of photobiology. 相似文献
983.
The epidermal growth factor (EGF)-like domain of the bovine blood coagulation factor IX (45-87) carrying glucose at Ser(53) was synthesized by a solid-phase method using 9-fluorenylmethoxycarbonyl (Fmoc)-amino acids. The introduction of Ser(53) was carried out using the benzotriazolyl ester of Fmoc-serine carrying an unmasked glucose. The remaining sequence was also introduced using the benzotriazolyl ester. HPLC analysis of the crude peptide shows that acylation of the free hydroxyl group of the glucose was not significant, demonstrating that the amino acid carrying an unmasked carbohydrate is a useful building block for solid-phase synthesis. 相似文献
984.
Maeda Y Miyashita J Hasegawa T Wakahara T Tsuchiya T Nakahodo T Akasaka T Mizorogi N Kobayashi K Nagase S Kato T Ban N Nakajima H Watanabe Y 《Journal of the American Chemical Society》2005,127(35):12190-12191
The reversible and regioselective reaction of La@C82 with cyclopentadiene was carried out. The activation and thermodynamic parameter of the retro-reaction was estimated from the Arrhenius plots of the rate constants. 相似文献
985.
An amperometric glucose ring-disk biosensor based on a ruthenium complex mediator of low redox potential was fabricated and evaluated. This thin-layer radial flow microsensor (10 μl) with ring-disk working electrode displayed remarkable amperometric sensitivity. For Ru3(μ3-O)(AcO)6(Py)3(ClO4) (Ru-Py), a trinuclear oxo-acetate bridged cluster, a reversible redox curve of low redox potential and narrow potential window (redox potentials were −0.190 and −0.106 V versus Ag/AgCl wire, respectively) was observed, which is comparable to many reported mediators such as ferrocene derivatives and other ruthenium complexes. The glucose and hydrogen peroxide assays were carried out with this complex-modified electrode Ru-Py-HRP-GOx/Nafion. The sensitivity was obtained 24 nA (15.4 mA M−1 cm−2) for 10 μM glucose and 126 nA (160 mA M−1 cm−2) for 5 μM H2O2, respectively with a working potential at 0 V versus Ag/AgCl. Ascorbic acid was studied as interference to the glucose assay. The application of 0 V potential versus Ag/AgCl did not avoid the occurrence of the oxidation of ascorbic acid, however, the pre-coating of ascorbate oxidase on the disk part of the ring-disk working electrode efficiently pre-oxidized the ascorbic acid and hence eliminated its interference on the glucose response. The practical reliability was also evaluated by assaying the dialysate from the prefrontal cortex of Wistar rats. 相似文献
986.
The locally projected self-consistent field molecular orbital method for molecular interaction (LP SCF MI) is reformulated for multifragment systems. For the perturbation expansion, two types of the local excited orbitals are defined; one is fully local in the basis set on a fragment, and the other has to be partially delocalized to the basis sets on the other fragments. The perturbation expansion calculations only within single excitations (LP SE MP2) are tested for water dimer, hydrogen fluoride dimer, and colinear symmetric ArM+ Ar (M = Na and K). The calculated binding energies of LP SE MP2 are all close to the corresponding counterpoise corrected SCF binding energy. By adding the single excitations, the deficiency in LP SCF MI is thus removed. The results suggest that the exclusion of the charge-transfer effects in LP SCF MI might indeed be the cause of the underestimation for the binding energy. 相似文献
987.
Tadashi Nakata Takaaki Kuwabara Yōichirō Tani Takeshi Oishi 《Tetrahedron letters》1982,23(9):1015-1016
()-Oudemansin has been synthesized starting from -cinnamaldehyde by a route involving the stereoselective Zn(BH4)2 reduction of β-keto ester. 相似文献
988.
Both the enantiomers of sclerosporin and sclerosporal were synthesized from (-)-carvone. (4R,9R,10S)-(+)-Sclerosporin and (4R,9R,10S)-(-)-sclerosporal were identified as the natural enantiomers by a comparison of their CD-spectra. An intramolecular Diels-Alder route was proved to be an efficient method of preparing sufficient amounts of (+)- for the biological study. 相似文献
989.
Terutaka Watanabe Takeshi Wada Masaaki Takehisa Sueo Machi 《Journal of polymer science. Part A, Polymer chemistry》1974,12(8):1609-1618
The radiation-induced polymerization of ethylene in cyclohexane was carried out in a reactor of 100 ml capacity under a range of temperature of 25–150°C, dose rate of 4.1 × 104–2.9 × 105 rad/hr, pressure of 200 kg/cm2, and amount of cyclohexane of 20–90 ml. The polymerization was found to proceed at a steady state from the beginning. The polymerization rate is maximum at ca. 50 ml of cyclohexane. The dose rate exponent of the polymerization rate was 0.6 at every temperature from 25 to 150°C. The polymer molecular weight is in the range of 103–104, independent of dose rate, and decreases with increasing amount of cyclohexane. The molecular weight distribution is unimodal and narrow. Kinetic analysis of these results indicates that the polymerization proceeds via a simple scheme of homogeneous polymerization and the polymer molecular weight was determined by the chain transfer reaction which takes place mostly with cyclohexane. The unimodal and narrow molecular weight distribution is also consistent with the homogeneous polymerization scheme. 相似文献
990.
Fumio Hamazu Sumio Akashi Tatsuya Koizumi Toshikazu Takata Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》1993,31(4):1023-1028
Various p-substituted benzyl p-hydroxyphenyl methyl sulfonium salts ( 2 ) were synthesized and their initiator activities were evaluated in bulk polymerization of glycidyl phenyl ether (PGE). The order of the activity was found to be 2b (X = CH3) > 2a (X = H) ≈ 2c (X = Cl) > 2d (X = NO2), indicating that the introduction of an electron-donating group enhanced the activity. In Hammett's plots, the logarithm of the ratio of the polymerization rates (log kx/kH) was correlated with σ+ρ better than with σp and a negative ρ+ value (-1.18) was obtained. Reaction of 2a with benzyl mercaptan mainly gave dibenzyl sulfide and p-hydroxyphenyl methyl sulfide. The obtained results seemed to demonstrate that the OH group of the aryl group yielded no proton as initiator for the polymerization, whereas the benzyl group caused the polymerization, which was initiated by the corresponding benzyl cation formed by C? S bond cleavage. © 1993 John Wiley & Sons, Inc. 相似文献