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81.
82.
Ishikawa T Ishii H Shimizu K Nakao H Urano J Kudo T Saito S 《The Journal of organic chemistry》2004,69(23):8133-8135
Diastereoselective total synthesis of isocarbacyclin, which features a fused bicyclic key intermediate available from l-ascorbic acid, is described. The key intermediate was prepared in multigram quantities by the Pauson-Khand reaction of l-ascorbic acid-based (R)-4,4-diallyl-2,2-dimethyl-5-(trimethylsilyl)ethynyl-1,3-dioxolane (3), discriminating diastereotopic groups and faces of the geminal allyl substituents. 相似文献
83.
84.
Does there exist any equivalence between the notions of inconsistency and consequence in paraconsistent logics as is present
in the classical two valued logic? This is the key issue of this paper. Starting with a language where negation (?{\neg}) is the only connective, two sets of axioms for consequence and inconsistency of paraconsistent logics are presented. During
this study two points have come out. The first one is that the notion of inconsistency of paraconsistent logics turns out
to be a formula-dependent notion and the second one is that the characterization (i.e. equivalence) appears to be pertinent
to a class of paraconsistent logics which have double negation property. 相似文献
85.
Teruhiko Maekawa Yutaka Ozaki Hiroshi Yoshioka Seizo Okamura 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(5):731-743
The radiation-induced polymerization of acrylonitrile in the frozen aqueous solutions of various metal chlorides and zinc halides was studied to compare the accelerating effect of metal cations and halogen anions. Among metal chlorides examined, zinc, stannous, manganese, and nickel cations gave greater rates and degrees of polymerization. Of the halogen anions, the rate of polymerization decreased in the order, Br?, CI?, SCN? ? I?, CH3CO2 ?, and the degree of polymerization decreased in the order, Br?, SCN? ? CI? ? I? ? CH3CO2 ?. The increase of the rate and the degree of polymerization was confirmed below the eutectic temperatures of the hydrated metal chlorides and ice. This suggests that the increment of the rate and the degree of polymerization is attributed to formation of hydrated metal chloride-acrylonitrile complexes accompanied by their solidification in eutectic mixtures with ice. The radioactivation analysis of polymers obtained in frozen dilute aqueous zinc bromide solution reveals appreciable contribution of water to generation of initiating species. 相似文献
86.
We simulate viscous fingering generated by separating two plates with a constant force, in a lifting Hele-Shaw cell. Variation in the patterns for different fluid viscosity and lifting force is studied. Viscous fingering is strongly affected by anisotropy. We report a computer simulation study of fingering patterns, where circular or square grooves are etched on to the lower plate. Results are compared with experiments. 相似文献
87.
Yoshifumi Hanada Teizi Tanizaki Minoru Koga Hiroaki Shiraishi Mitsuyuki Soma 《Analytical sciences》2002,18(4):441-444
Liquid chromatography/mass spectrometry (LC/MS) has been applied to analyze N,N'-ethylenebisdithiocarbamate fungicides (EBDCs: manzeb, maneb and zineb) in environmental water samples. The EBDCs that are zinc and/or manganese salts are transformed into readily water-soluble sodium salts by adding an alkaline EDTA solution. The N,N'-ethylenebisdithiocarbamate anion is extracted into chloroform-hexane (3:1) as an ion pair with tetrabutylammonium, and then S-alkylated with methyl iodide. The extraction and derivatization are carried out at room temperature. The derivatized ethylenebisdithiocarbamic acid dimethyl ester is introduced into an LC/MS equipped with a negative ion electrospray ionization interface. Identification of the compound is performed with the specific quasi-molecular ion, and the quantitative analyses are carried out using the peak areas. The average recoveries and coefficients of variation of EBDCs at sub-ppb level are 79.1% and 29.3% (n = 6), respectively. The limit of detection based on standard deviation of 0.043 microg/L for manzeb is achieved. 相似文献
88.
N Kitahara-Tanabe Y Tanabe A Morikawa D Mizuno G Soma 《Chemical & pharmaceutical bulletin》1991,39(2):417-420
To elucidate the mechanism of tumor necrosis factor (TNF) production, we analyzed proteins produced in macrophages sharing the epitope of TNF according to the priming and triggering of TNF production. Rabbit alveolar macrophages primed with Bacillus Calmette-Guerin (BCG) were isolated and cultured in vitro with 35S-methionine, and the proteins produced were analyzed using anti-rabbit TNF monoclonal antibody. Primed with BCG, alveolar macrophages synthesized two proteins with molecular sizes of 50 and 17 kilodaltons (kDa) (p50 and p17) sharing the same epitope with mature TNF within the cells. These two proteins were released into the medium where other proteins were detected without TNF-activity. Cultured with lipopolysaccharide (LPS triggering), the primed alveolar macrophages released TNF-activity into the medium where p17 together with many larger proteins was detected by immunoprecipitation. In vitro translation of messenger ribonucleic acid (mRNA) from BCG-primed macrophages showed that primary TNF has a molecular size of 28 kDa (p28). These results suggest that active TNF of p17 is secreted when triggered via post-translational processing of the precursor molecules synthesized through priming with BCG. 相似文献
89.
Teruhiko Soma 《Proceedings of the American Mathematical Society》2002,130(4):1221-1223
We will show that any infinite sequence of epimorphisms between finitely generated hyperbolic 3-manifold groups eventually consists of isomorphisms.
90.
The temperature dependence of the thermal expansion for GaAs and InP is investigated theoretically using the experimental pressure derivatives of elastic stiffness constants and phonon frequencies. The linear correlation between the transverse acoustical mode Grüneisen parameter γXTA and the metallic transion pressure Pt obtained by Weinstein is not satisfied for GaAs and InP, but the observed thermal expansion of GaAs is well reproduced. In addition, the linear expansion coefficient of InP is predicted theoretically as a function of temperature. Then, the phonon dispersion curves of GaAs and InP at their covalent-metallic transition pressures are quantitatively shown. 相似文献