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121.
Three novel diterpenes, phomactins K–M (13), were isolated from the cultures of an unidentified marine-derived fungus. The structures of 13 were elucidated from spectroscopic data (NMR, MS, IR), and the absolute configurations of 1, 2, and the relative configuration of 3 were determined by X-ray diffraction analysis.  相似文献   
122.
Composition control of aromatic poly(thioester‐amide) was examined by the reaction‐induced phase separation during polymerization of S‐acetyl‐4‐mercaptobenzoic acid (AMBA) and p‐acetylaminobenzoic acid (AABA) in aromatic solvent. The poly(thioester‐amide)s were obtained as precipitates and their yields became lower at the middle range of the content of AMBA in feed (χf). The contents of p‐mercaptobenzoyl (MB) moiety (χp) in the precipitates prepared without shearing were in good agreement with the χf values. In contrast to this, the χp values of the precipitates prepared at χf of 50–70 mol % under shearing were much lower than the χf values. The reaction rate of AMBA increased with shearing, whereas that of AABA was unchanged by shearing. This shearing effect on the reaction rates accelerated to form the homo‐oligomers. The solubility of MB oligomers enhanced by shearing, whereas that of p‐benzamide oligomers did not enhance owing to the strong interaction through hydrogen bonding. The MB oligomers were inhibited to be precipitated, resulting in the lower χp values than the χf values. The composition could be controlled by the application of the shearing to the heterogeneous polymerization. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4301–4308  相似文献   
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124.
Three methods for the determination of rat hepatocellular thiols by high-performance liquid chromatography (HPLC) with fluorescence (FL) detection have been developed. The thiols in the cells were tagged with three fluorogenic reagents, SBD-F, ABD-F and DBD-F. These reagents could permeate into cells and effectively reacted with thiols to produce highly fluorescent derivatives. These derivatives fluoresced in the long wavelength region at around 530 nm (excitation at around 380 nm). The five biological thiols tagged were perfectly separated by reversed-phase liquid chromatography and were sensitively and selectively detected without any interference from endogenous substanaces. The main thiol in the cells was reduced GSH and the concentration was at the mM level. The proposed procedures were applied to the determination of hepatocellular GSH after treatment of environmental pollutants such as volatile organic compounds (VOC) and endocrine disrupting chemicals (EDC). From the comparison of intracellular GSH concentration, the test compounds were classified into four groups: compounds of strong depletion (eg triphenyltin chloride, hexachlorocyclohexene, nonylphenol, bromoacetic acid, 4-chlorobenzyl chloride and 1,3-dichloropropene), slight decrease (eg bisphenol A, benzo[a]pylene, carbon tetrachloride and benzene), slight increase (eg bromoform and toluene), and no effect (eg 1,1,1-trichloroethane, 1,1,2-trichloroethane and 1,2-dichloroethane). Although the decrease of GSH concentration does not reflect the cytotoxicity of chemicals, the proposed procedure utilizing isolated rat hepatpcytes seems to be useful for investigating the bioactivation of VOC, and EDC, etc.  相似文献   
125.
A new term, spherophylon, indicates a unit of life higher than the individual level. To define this term, critical notes are given on the meaning of age in terms of life, the interrelationships among the elements of biodiversity, and an analogy of development between the multicellular body of an individual and the spherophylon. Life is compared at various levels; at the level of the cell, the individual as a multicellular organism, and the spherophylon. The biology of the spherophylon is discussed in the context of integrative biology.  相似文献   
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127.
8-Hydroxyquinoline derivative 1 as a fluorescent chemosensor for Zn2+ was synthesized. Because Cd2+ is often found with Zn2+ in the environment and can form fluorescent complexes with chelating fluorophores, a potentially important property of chemosensors for Zn2+ is their selectivity for Zn2+ over Cd2+. The Zn2+ or Cd2+ complexes of 1 gave an emission band from the 1:1 complex, but the fluorescence intensity for Cd2+ was a half of that for Zn2+. Ligand 1 is suited for use as a fluorescent chemosensor for Zn2+.  相似文献   
128.
A Mössbauer effect measurement has been done for Fe?N, Fe?Al?C and Fe?Ni?C austenite in order to study the interaction between the interstitial atoms and their distribution among the octahedral sites of the fcc lattice, together with the influence of Al and Ni atoms. The spectra for Fe?N and Fe?Al?C austenite are decomposed into three components; one singlet γ0, and two sets of doublet γ1 and γ2, with different quadrupole splittings, while no γ2 component is found in the spectrum for Fe?Ni?C. By analyzing the component ratio in each spectrum, it is concluded that, in Fe?N and Fe?Al?C, the interaction between 2nd nearest neighboring nitrogen or carbon atoms is attractive, and is repulsive between 1st nearest for Fe?N, and that the interaction between 2nd nearest atoms is repulsive for Fe?Ni?C. By measuring the spectra of Fe?Ni?C in magnetic field, the sign of EFG for most of the γ1 component is determined to be negative.  相似文献   
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130.
We present the results of searches for decays of B mesons to final states with a b1 meson and a charged pion or kaon. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 382x10(6) BB[over ] pairs produced in e+e- annihilation. The results for the branching fractions are, in units of 10(-6), B(B+-->b1(0)pi+)=6.7+/-1.7+/-1.0, B(B+-->b1(0)K+)=9.1+/-1.7+/-1.0, B(B0-->b1(-/+)pi(+/-))=10.9+/-1.2+/-0.9, and B(B0-->b1(-)K+)=7.4+/-1.0+/-1.0, with the assumption that B(b1-->omega pi)=1. We also measure charge and flavor asymmetries A(ch)(B+-->b1(0)pi+)=0.05+/-0.16+/-0.02, Ach(B+-->b1(0)K+)=-0.46+/-0.20+/-0.02, A(ch)(B0-->b1(-/+)pi(+/-))=-0.05+/-0.10+/-0.02, C(B0-->b1(-/+)pi(+/-))=-0.22+/-0.23+/-0.05, DeltaC(B0-->b1(-/+)pi(+/-))=-1.04+/-0.23+/-0.08, and A(ch)(B0-->b1(-)K+)=-0.07+/-0.12+/-0.02. The first error quoted is statistical, and the second systematic.  相似文献   
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