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91.
The Niigata Prefectural Govemment has been carrying out an environmental radiation monitoring around the Kashiwazaki Kariwa Nuclear Power Station. Most of the gamma-ray dose rate was dependent on the natural radiation from the ground. The investigations wanted to detemine the natural radiation level in the Kashiwazaki Kariwa area. Gamma-ray dose rates were measured with a scintillation detector. Additionally, the quantity of radionuclides and their contribution to the dose rate were obtained by an in situ measurement method.  相似文献   
92.
A series of supramolecular complexes of various cytochrome c proteins with 18-crown-6 derivatives behave as cold-active synzymes in the H2O2 oxidation of racemic sulfoxides. This interesting behavior contrasts with native functionality, where the employed proteins act as electron transfer carriers. ESI-MS. UV, CD, and Raman spectroscopic characterizations reveal that four or five 18-crown-6 molecules strongly bind to the surface of the cytochrome c and also that nonnatural low-spin hexacoordinate heme structures are induced in methanol. Significantly, crown ether complexation can convert catalytically inactive biological forms to catalytically active artificial forms. Horse heart, pigeon breast, and yeast cytochromes c all stereoselectively oxidize (S)-isomers of methyl tolyl sulfoxide and related sulfoxides upon crown ether complexation. These supramolecular catalysts show the highest efficiency and enantiomer selectivity at -40 degrees C in the H202-dependent sulfoxide oxidation, while oxidative decomposition of the heme moieties predominantly occurs at room temperature. The oxidation reactivity of the employed sulfoxides is apparently related to steric constraints and electrochemical oxidation potentials of their S=O bonds. Among the cytochrome c complexes, yeast cytochrome c demonstrates the lowest catalytic activity and degradation reactivity. It has a significantly different protein sequence, suggesting that crown ether complexation effectively activates heme coordination but may additionally alter the native backbone structure. The proper combination of cytochrome c proteins, 18-crown-6 receptors, and external circumstances can be used to successfully generate "protein-based supramolecular catalysts" exhibiting nonbiological reactivities.  相似文献   
93.
A variety of lariat ethers were employed to solubilize water-soluble cytochrome c in methanol, in which alcohol, ether, ester, amine, and amide functionalities were attached as cation-ligating side arms to 18-crown-6, 15-crown-5, and 12-crown-4 rings. Among these lariat ethers, the alcohol-armed 18-crown-6 derivative offered the highest solubilization efficiency for cytochrome c via supramolecular complexation. The resulting cytochrome c-lariat ether complexes were electrochemically and spectroscopically characterized and confirmed to have redox-active heme structures of 6-coordinate low-spin population in methanol. Some of them catalyzed the oxidation of pinacyanol chloride with hydrogen peroxide in methanol and exhibited higher activities than unmodified cytochrome c and its poly(ethylene glycolated) derivative. Since the supramolecular complexation between lariat ether and cytochrome c includes extremely simple procedures, it provides a facile preparation method of effective biocatalysts working in organic solvents from metalloproteins.  相似文献   
94.
A new diacylated 8-C-glucosylanthocyanin was isolated from the purple flowers of Tricyrtis formosana 'Fujimusume' as one of the major anthocyanins along with four known pigments. The structure of this pigment was determined to be 8-C-(6-O-trans-sinapoyl)-beta-glucopyranosylcyanidin 3-O-(6-O-malonyl-beta-glucopyranoside) by chemical and spectroscopic methods. In addition, four known pigments, 8-C-glucosylcyanidin 3-malonylglucoside, cyanidin 3-glucoside, cyanidin 3-rutinoside and cyanidin 3-malonylglucoside, were identified as the major anthocyanins in the flowers.  相似文献   
95.
All the metastable transitions observed above m/z 39 in the first field-free region were compared for the three positional isomers of dimethoxybenzene. The observed isomer-dependent fragmentation processes, in particular the formation and decomposition of the m/z 95 (C6H7O)+ ion, are discussed in terms of two competing fragmentations [elimination of CH3 and CHnO (n = 1–3) and formation of methoxycyclopentadienyl and protonated phenol ions] and the relative energies of several isomers of the C6H7O+ ion calculated with molecular orbital theory.  相似文献   
96.
The inhibitory effect of an anabolic steroid, stanozolol, on testicular microsomal cytochrome P-450 (17 alpha-hydroxylase/C17,20-lyase) (P-450(17 alpha/lyase] and the nature of the interaction were compared with those of other anabolic steroids, furazabol and mestanolone. Stanozolol markedly inhibited delta 16-C19-steroid synthesizing activity, 17 alpha-hydroxylase and C17,20-lyase activities, which were mediated by oxygenase activities of testicular microsomal cytochrome P-450(17 alpha/lyase). In addition, stanozolol was a competitive inhibitor of 17 alpha-hydroxylase (Ki = 6.31 microM) and C17,20-lyase (Ki = 1.30 microM) activities in the reconstituted enzyme system. The interaction of cytochrome P-450&17 alpha/lyase) with stanozolol induced a type I difference spectrum (peak at 387 nm and trough at 418 nm) with a dissociation constant (Ks) of 1.47 microM.  相似文献   
97.
Cobalt ferrite particles with diameters ranging from a few micrometer to about 15 nm were synthesized using a modified oxidation process. The fine control of the particle size was achieved by introducing various concentrations of Fe(3+) ions at the beginning of the reaction. Among the particle sizes obtained by using this method, particles with a grain size of about 36 nm showed a magnetization (M(s)) of 64 emu/g and a maximum coercivity (H(c)) of 2020 Oe at room temperature. The corresponding squareness ratio was found to be 0.53.  相似文献   
98.
99.
Molecules confined in nanopores show unusual behavior not seen in bulk systems. The present paper reports on molecular dynamics simulations of unusual freezing behavior in confined Ar. Similar to bulk Ar, liquid Ar confined in pores with a diameter D>15sigma (5.1 nm), where sigma is the diameter of the Ar atom, crystallizes when the cooling rate is lower than a critical value (Qc). We also find that the spatial confinement does not have significant influence on Qc when D>15sigma (5.1 nm). In the pore of 10sigma (3.4 nm) in diameter, on the other hand, the behavior is dramatically changed. Crystalline Ar does not appear inside the pore even when the system is cooled at a rate lower than the Qc in the bulk system by over two orders of magnitude. Instead, amorphous Ar characterized by local icosahedral configurations is formed in the pore. We further find that, even when crystalline Ar is formed outside the pore, it does not grow deeply into the pore. This supports that the amorphous Ar is actually the most stable phase in the pore. It is well known that Ar is a poor glass former. Our finding that even such an amorphous Ar is the most stable in the pore suggests that, in any system, it is possible to prepare amorphous structure selectively by using nano-molds.  相似文献   
100.
Simple gas chromatographic-mass spectrometric determination of hydrophilic organic compounds in environmental water was developed. A cartridge containing activated carbon fiber felt was made by way of trial and was evaluated for solid-phase extraction of the compounds in water. The hydrophilic compounds investigated were acrylamide, N,N-dimethylacetamide, N,N-dimethylformamide, 1,4-dioxane, furfural, furfuryl alcohol, N-nitrosodiethylamine and N-nitrosodimethylamine. Overall recoveries were good (80-100%) from groundwater and river water. The relative standard deviations ranged from 4.5 to 16% for the target compounds. The minimum detectable concentrations were 0.02 to 0.03 microg/l. This method was successfully applied to several river water samples.  相似文献   
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