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31.
Shigeyuki Mayama Toshikazu Tani Tamio Ueno Kazumasa Hirabayashi Tadakazu Nakashima Hiroshi Fukami Yukio Mizuno Hiroshi Irie 《Tetrahedron letters》1981,22(22):2103-2106
The major phytoalexin from oat leaves has been identified as 2-[2-(4-hydroxyphenyDethenyl] -6-hydroxy-4H-3,1-benzoxazin-4-one (). 相似文献
32.
While most of CO-bound hemes are easily photodissociated with a quantum yield of nearly unity, we occasionally encounter a CO-heme which appears hardly photodissociable under the ordinary measurement conditions of resonance Raman spectra using CW laser excitation and a spinning cell. This study aims to understand such hemes theoretically, that is, the excited-state properties of the five-coordinate heme-CO adduct (5cH) as well as the 6c heme-CO adduct (6cH) with a weak axial ligand. Using a hybrid density functional theory, we scrutinized the properties of the ground and excited spin states of the computational models of a 5cH and a water-ligated 6cH (6cH-H(2)O) and compared these properties with those of a photodissociable imidazole-ligated 6cH (6cH-Im). Jahn-Teller softening for the Fe-C-O bending potential in the a(1)-e excited state was suggested. The excited-state properties of 6cH-Im and 5cH were further studied with time-dependent DFT theory. The reaction products of 6cH-Im and 5cH were assumed to be quintet and triplet states, respectively. According to the time-dependent DFT calculations, the Q excited state of 6cH-Im, which is initially a pure pi-pi state, crosses the Fe-CO dissociative state (2A') without large elongation of the Fe-CO bond. In contrast, the Q state of the 5cH does not cross the Fe-CO dissociative state but results in the formation of the excited spin state with a bent Fe-C-O. Consequently, photoisomerization from linear to bent Fe-C-O in the 5cH is a likely mechanism for apparent nonphotodissociation. 相似文献
33.
We have observed lasing in a complicated eigenmode of a quasi-stadium laser diode with an unstable resonator consisting of two curved end mirrors obeying an unstable resonator condition and two straight sidewall mirrors. The laser was fabricated by application of a reactive-ion-etching technique to a molecular beam epitaxy-grown graded-index separate-confinement heterostructure single-quantum-well GaAs/AlGaAs structure. The far-field pattern shows that the lasing mode corresponds to the complicated lowest-loss mode obtained numerically by an extended Fox-Li method. 相似文献
34.
To non-invasively determine the condition of the masticatory muscles during chewing in real time, we used near-infrared spectroscopy and measured the masseter muscle. It increased in size, while the deoxy Hb in this muscle experienced the change in the short cycle by chewing. Periodic change of deoxy Hb was in agreement with the vertical movement of the lower jaw. It was found that the amount of increase in the deoxy Hb differs depending on the hardness of food being chewed. Moreover, by carrying out simultaneous measurement of the masseter muscles on both side of the jaw it was possible to determine the predominant muscles currently used in chewing. 相似文献
35.
An optical fiber multi-function device consisting of a single gradient-index-rod lens and a multi-facet blazed reflection
grating is proposed to simultaneously realize functions of wavelength demultiplexing and optical signal distribution in a
multimode optical fiber transmission system. We analyzed the demultiplexing characteristics and the tolerance of optical components
using the ray trace method. This device can realize not only low loss optical signal distribution but also offers improved
demultiplexing characteristics in comparison with the previously proposed demultiplexer-multiposition switch. The following
characteristics are expected from the design using commercially available optical components: a working band of 0.64–0.88
μm, channel separation of 34–36 nm, 3 dB bandwidth of 27–28 nm, channel cross-talk of less than - 40 dB and minimum excess
insertion loss of 0.9–2.1 dB. 相似文献
36.
D. Okai R. Nagai G. Motoyama T. Fukami T. Yamasaki Y. Yokoyama H.M. Kimura A. Inoue 《Physica C: Superconductivity and its Applications》2010,470(20):1048-1051
The superconducting property of Zr(1−x)Cox (x = 10–50 at.%) alloys and a Zr55Co30Al15 bulk metallic glass fabricated using techniques of rapid solidification was investigated. The Zr55Co30Al15 alloy crystallized by heat treatment in a vacuum atmosphere exhibited superconductivity of Tc,on = 2.4 K. This was attributable to the superconducting property of a crystalline Zr–Co alloy precipitated in the Zr55Co30Al15 alloy. The Tc,on of the crystalline Zr(1−x)Cox alloy was sensitive to the Co content. The increase of Co content for the Zr(1−x)Cox alloy led to the decrease of Tc,on. The Zr(1−x)Cox alloy exhibited superconductivity of a maximum Tc,on = 3.9 K for the Zr80Co20 alloy with superconducting nanocrystal particles embedded in the amorphous matrix. 相似文献
37.
Norihiro?SadatoEmail author Hiroki?Yamada Tomohisa?Okada Masaki?Yoshida Takehiro?Hasegawa Ken-Ichi?Matsuki Yoshiharu?Yonekura Harumi?Itoh 《BMC neuroscience》2004,5(1):56
Background
Sign-language comprehension activates the auditory cortex in deaf subjects. It is not known whether this functional plasticity in the temporal cortex is age dependent. We conducted functional magnetic-resonance imaging in six deaf signers who lost their hearing before the age of 2 years, five deaf signers who were >5 years of age at the time of hearing loss and six signers with normal hearing. The task was sentence comprehension in Japanese sign language. 相似文献38.
Dr. Yusuke Sato Yushuang Zhang Dr. Seiichi Nishizawa Dr. Takehiro Seino Kodai Nakamura Dr. Minjie Li Prof. Dr. Norio Teramae 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(40):12719-12724
A fluorescence assay for theophylline, one of the common drugs for acute and chronic asthmatic conditions, has been developed based on an abasic site‐containing DNA duplex aptamer (AP aptamer) in combination with an abasic site‐binding fluorescent ligand, riboflavin. The assay is based on the competitive binding of theophylline and riboflavin at the abasic (AP) site of the AP aptamer. In the absence of theophylline, riboflavin binds to the receptor nucleotide opposite the AP site, which leads to fluorescence quenching of the riboflavin. Upon addition of theophylline, competitive binding occurs between theophylline and riboflavin, which results in an effective fluorescence restoration due to release of riboflavin from the AP site. From an examination of the optimization of the AP aptamers, the complex of riboflavin with a 23‐mer AP aptamer (5′‐TCT GCG TCC AGX GCA ACG CAC AC‐3′/5′‐GTG TGC GTT GCC CTG GAC GCA GA‐3′; X : the AP site (Spacer C3, a propylene residue)) possessing cytosine as a receptor nucleotide was found to show a selective and effective fluorescence response to theophylline; the limit of detection for theophylline was 1.1 μM . Furthermore, fluorescence detection of theophylline was successfully demonstrated with high selectivity in serum samples by using the optimized AP aptamer and riboflavin. 相似文献
39.
Hiroaki Shimomoto Dai Fukami Tomomi Irita Ken‐ichi Katsukawa Takabumi Nagai Shokyoku Kanaoka Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2012,50(8):1547-1555
Various types of fluorine‐containing star‐shaped poly(vinyl ether)s were successfully synthesized by crosslinking reactions of living polymers based on living cationic polymerization. Star polymers with fluorinated arm chains were prepared by the reaction between a divinyl ether and living poly(vinyl ether)s with fluorine groups (C4F9, C6F13, and C8F17) at the side chain using cationogen/Et1.5AlCl1.5 in a fluorinated solvent (dichloropentafluoropropanes), giving star‐shaped fluorinated polymers in high yields with a relatively narrow molecular weight distribution. The concentration of living polymers for the crosslinking reaction and the molar feed ratio of a bifunctional vinyl ether to living polymers affected the yield and molecular weight of the star polymers. Star polymers with block arms were prepared by a linking reaction of living block copolymers of a fluorinated segment and a nonfluorinated segment. Heteroarm star‐shaped polymers containing two‐ or three‐arm species were synthesized using a mixture of different living polymer species for the reaction with a bifunctional vinyl ether. The obtained polymers underwent temperature‐induced solubility transitions in various organic solvents, and their concentrated solutions underwent sol–gel transitions, based on the solubility transition of a thermoresponsive fluorinated segment. Furthermore, a slight amount of fluorine groups were shown to be effective for physical gelation when those were located at the arm ends of a star polymer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
40.
Hiroshi DanjoWataru Sasaki Takehiro MiyazakiTsuneo Imamoto 《Tetrahedron letters》2003,44(17):3467-3469
P-Chirogenic trialkylphosphonium salts were prepared from the corresponding free phosphines by treatment with a strong acid (HBF4 or HOTf). No racemization of the phosphonium salts occurred in methanol or water even at considerably high temperature. The salts were conveniently used in rhodium-catalyzed asymmetric hydrogenation of enamides. 相似文献