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排序方式: 共有492条查询结果,搜索用时 15 毫秒
51.
Tsutom Hasuikea Toshihiko Hattori Toshio Hayashi Seiichi Wakaizumi 《Zeitschrift fur Physik C Particles and Fields》1997,76(1):127-132
Due to the large mass of top quark, CP violation in the top-quark decay is sensitive to the interactions mediated by Higgs bosons. We consider CP violation in t → W + b decay by calculating consistently in unitary gauge the CP-violating up-down asymmetry of the leptons from W boson decays in t → W + b, defined by Grz?dkowski and Gunion, in the two-Higgs doublet model with CP-violating neutral sector. The asymmetry is shown to be at most of the order of (1–4) × 10-4 for tan β = 1.0, where tan β is the ratio of vacuum expectation values for the two neutral Higgs bosons. 相似文献
52.
53.
Fumi ShozuiKen’ichiro Matsumoto Ren MotohashiJian Sun Toshifumi SatohToyoji Kakuchi Seiichi Taguchi 《Polymer Degradation and Stability》2011,96(4):499-504
A poly(lactic acid) (PLA)-like terpolyester consisting of 96 mol% lactate (LA), 1 mol% 3-hydroxybutyrate and 3 mol% 3-hydroxyvalerate was produced in recombinant Escherichia coli LS5218 expressing LA-polymerizing enzyme (LPE). The strain was grown on glucose with a feeding of valerate as the monomer precursor. The glass transition and melting temperatures of the terpolyester were close to those of chemically synthesized poly(L-LA)s (PLLAs) having similar molecular weights. Additionally, a blend of the terpolyester, which was composed entirely of (R)-LA (D-LA) due to the strict enantiospecificity of LPE, with PLLA formed a stereocomplex with higher melting temperature (201.9 °C). These results indicate that the biological PLA-like polyester produced via this one-step microbial process has comparable thermal properties to chemically synthesized PLAs. 相似文献
54.
Miura S Nishizawa S Suzuki A Fujimoto Y Ono K Gao Q Teramae N 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(50):14104-14110
A surface plasmon resonance (SPR) biosensor that carries DNA-binding small ligands has been developed for the detection of single-nucleotide polymorphisms (SNPs). 3,5-Diaminopyrazine derivatives, with a hydrogen-bonding profile fully complementary to the thymine base, were utilized as recognition elements on the sensor surface, and a target single-stranded DNA sequence was hybridized with a DNA probe containing an abasic site to place this site opposite a nucleobase to be detected. In a continuous flow of sample solutions buffered to pH 6.4 (0.25 M NaCl), the 3,5-diaminopyrazine-based SPR sensor can detect an orphan nucleobase in the duplex with a clear selectivity for thymine over cytosine, guanine, and adenine (5'-GTT GGA GCT GXG GGC GTA GGC-3'/3'-CAA CCT CGA CNC CCG CAT CCG-5'; X=abasic site, N=target nucleobase G, C, A, or T). The SPR response was linear in the concentration range 10-100 nM. Allele discrimination is possible based on the combination of different binding surfaces in a flow cell of the SPR system, which is demonstrated for the analysis of the thymine/cytosine mutation present in 63-meric polymerase chain reaction (PCR) amplification products (Ha-ras gene, codon 12, antisense strand). Comparison with a bulk assay based on 3,5-diaminopyrazine/DNA binding shows that the immobilization of 3,5-diaminopyrazine derivatives on the SPR sensor allows more sensitive detection of the target DNA sequence, and binding selectivity can be tuned by controlling the salt concentration of sample solutions. These features of the DNA-binding small-molecule-immobilized SPR sensor are discussed as a basis for the design of SPR biosensors for SNP genotyping. 相似文献
55.
Sato Y Nishizawa S Teramae N 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(41):11650-11656
A new class of label-free molecular beacon (MB) system based on DNA strands that contain abasic (AP) sites (AP-DNA) and adopt stem-loop structures, in combination with fluorescent ligands that bind these AP sites, has been developed. Unlike a conventional MB, which requires covalent labeling of the MB with a fluorophore and a quencher, the developed system (APMB) does not require covalent attachment of signal transduction units. Detailed sensing functions of a series of APMB systems were examined with the aid of the fluorescent ligand named ATMND to provide insight into the design strategy for APMB systems. The effects of the stem length and the position of the AP site in the stem moiety on the fluorescence response of the APMB system were examined. Genotyping of a G/C SNP of PCR amplification products was successfully demonstrated with the APMB system and blue-fluorescent ATMND as a ligand. The APMB system was further extended to a system that utilized green-fluorescent lumiflavin. 相似文献
56.
Thermoplastic elastomer was prepared from deproteinized natural rubber (DPNR) by graft-copolymerization of styrene, which was performed onto rubber particles of about 1 μm in diameter in latex stage with tert-butyl hydroperoxide/tetraethylenepentamine as an initiator. Suitable initiator concentrations were determined to be 3.3 × 10−2 and 20 × 10−2 mol/kg-rubber for the graft-coplymerization of styrene of 1.5 and 5.5 mol/kg-rubber, respectively, in which conversion and grafting efficiency of styrene were more than 90 mol% and 80 mol%, respectively. The resulting polystyrene, grafted onto the rubber particles, was characterized by size exclusion chromatography after ozonolysis. Morphology of the DPNR grafted with polystyrene (DPNR-graft-PS) was observed by transmission electron microscopy (TEM). Change in morphology after processing the DPNR-graft-PS at 150 °C was associated with change in mechanical properties, i.e. stress at strain of 1 and stress at break. The outstanding mechanical properties, maintained even after processing, were assigned to the thermoplasticity of the DPNR-graft-PS, based on the high conversion and high grafting efficiency. 相似文献
57.
Sato Y Honjo A Ishikawa D Nishizawa S Teramae N 《Chemical communications (Cambridge, England)》2011,47(20):5885-5887
We report on the selective binding of 2-amino-5,6,7-trimethyl-1,8-naphthyridine (ATMND) to C-C mismatch present in the hairpin structures of (CCG)(n) trinucleotide repeats that are associated with neurological diseases; this binding is accompanied by significant fluorescence quenching of ATMND. 相似文献
58.
Highly sensitive photoalignment of liquid crystals (LCs) can be realized by axis-selective triplet energy transfer. Addition of a triplet photosensitizer (phosphorescent donor) into a photocrosslinkable polymer tethering E-cinnamate side chains ensures dramatic enhancement of photosensitivity to generate the optical anisotropy of polymer film and surface-assisted LC photoalignment. Photoirradiation of triplet photosensitizer-doped polymer films with linearly polarized 365 nm light for the selective excitation of triplet sensitizer gives rise to optical anisotropy of cinnamates as a result of axis-selective triplet energy transfer. By analyzing phosphorescence spectra with theoretical Perrin's formula, we find that triplet energy transfer is efficient within a radius of ~0.3 nm from the triplet photosensitizer. Such photoaligned polymer films can be used for the surface-assisted orientation photocontrol of not only calamitic LC, but also discotic LC, even for extremely low exposure energies. The present procedure would be greatly advantageous for high-throughput fabrication of optical devices by photoalignment techniques. 相似文献
59.
Seiichi Takano Minoru Moriya Takashi Kamikubo Kou Hiroya Kunio Ogasawara 《Tetrahedron letters》1993,34(52):8485-8488
It has been revealed that the generation of 2-cyclohexenones from cis-1,4-dihydroxycyclohexene derivatives under PdCl2(PPh3)2-HCO2NH4 system takes place in an intramolecular pathway involving unprecedented mode of suprafacial 1,4-hydrogen migration across the 1,4-allylic centers. 相似文献
60.
Seiichi Yamaguchi 《Annali di Matematica Pura ed Applicata》1972,94(1):231-245
Summary Let M be a compact Sasakian space admitting a conformal Killing p-form u. Then, we show that the associated form ϑ of a conformal
Killing form u is a special Killing form with constant 1. Moreover we prove the decomposition theorem of u and seek the condition
for M to be a unit sphere.
Entrata in Redazione il 29 agosto 1971.
Delicated to ProfessorT. Adati on his 60th Birthday. 相似文献