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71.
72.
Antiviral activity of natural occurring flavonoids in vitro 总被引:2,自引:0,他引:2
Y Tsuchiya M Shimizu Y Hiyama K Itoh Y Hashimoto M Nakayama T Horie N Morita 《Chemical & pharmaceutical bulletin》1985,33(9):3881-3886
73.
Nobuyuki Ichinose Masahide Hagiri Jun-ichiro Kinugasa Nobuyuki Shichi Toshihiro Nakayama 《Research on Chemical Intermediates》2013,39(1):425-435
A charge-transfer (CT) complex of NOBF4 and hexamethoxybenzene (HMB), which gives out HMB?+ as a “fluorescent radical cation probe,” upon one-electron oxidation, has been designed to explore the excited state dynamics of contact radical ion pairs by laser-induced fluorescence and femtosecond transient absorption spectroscopic techniques. The acetonitrile solution of the CT complex showed weak fluorescence with a similar spectrum to that observed for free excited HMB radical cation (HMB?+*), suggesting the formation of HMB?+* upon the one-photonic excitation of the CT complex. The laser-power dependence of the fluorescence intensity supported the one-photonic excitation event. We have also observed a short-lived transient species but no long-lived species by femtosecond laser flash photolysis of the CT complex. The lifetime (6.5 ps) was in good accordance with its fluorescence quantum yield (2.5 × 10?5) and was able to assign the transient species to the fluorescent state, an excited radical ion pair [HMB ?+*/NO?]. All the events were completed within the inner sphere and the short lifetime of the transient species could be attributed to rapid back-electron transfer. It is concluded that the excited radical cation character in the excited state of the CT complex originates from the radical ion character in the CT complex in the ground state and that a relatively long lifetime of HMB?+* facilitates its observation even in the contact ion pair. 相似文献
74.
Yasuto Uchio Junzo Toyota Hiroshi Nozaki Mitsuru Nakayama Yoshifumi Nishizono Tsunao Hase 《Tetrahedron letters》1981,22(41):4089-4092
The structures of lobohedleolide (1) and (7Z)-lobohedleolide (2), two new cembranolides containing the α,β-unsaturated carboxylic acid system isolated from the Japanese soft coral Lobophytum hedleyi Whitelegge, were elucidated from spectral and chemical evidence, and the absolute configuration of (1) was determined by X-ray analysis of its p-bromophenacyl ester (9). Lobohedleolide (1) showed growth inhibition of the in vitro Hella cells. 相似文献
75.
We have investigated the nonradiative deactivation process of malachite green in the singlet excited states, S(1) and S(2), by high-level ab initio quantum chemical calculations using the CASPT2//CASCF approach. The deactivation pathways connecting the Franck-Condon region and conical intersection regions are identified. The initial population in the S(1) state is on a flat surface and the relaxation involves a rotation of phenyl rings, which leads the molecule to reach the conical intersection between the S(1) and S(0) states, where it efficiently decays back to the ground state. There exists a small barrier connecting the Franck-Condon and conical intersection regions on the S(1) potential energy surface. The decay mechanism from the S(2) state also involves the twisting motion of phenyl rings. In contrast to the excitation to the S(1) state, the initial population is on a downhill ramp potential and the barrierless relaxation through the rotation of substituted phenyl rings is expected. During the course of relaxation, the molecule switches to the S(1) state at the conical intersection between S(2) and S(1), and then it decays back to the ground state through the intersection between S(1) and S(0). In relaxation from both S(1) and S(2), large distortion of phenyl rings is required for the ultrafast nonradiative decay to the ground state. 相似文献
76.
H. Akimune T. Yamagata S. Nakayama M. Fujiwara K. Fushimi K. Hara K. Y. Hara K. Ichihara K. Kawase K. Matsui K. Nakanishi A. Shiokawa M. Tanaka H. Utsunomiya M. Yosoi 《Physics of Atomic Nuclei》2004,67(9):1721-1725
Trinucleon molecular structures in 6He and 6Be were investigated by using the 6Li(7Li, 7Be)6He reaction at 455 MeV and 6Li(3He, t)6Be reaction at 450 MeV, respectively. Binary decays into t + t from a broad state at E x =18.0±1.0 MeV in 6He and into 3He + 3He from one at E x =18.0±1.2 MeV in 6Be, respectively, were observed by measuring trinucleon cluster decays in coincidence with reaction particles. The branching ratios for binary decay were estimated to be about 0.7 for 6He and 6Be. These large branching ratios show that a trinucleon cluster state exists as an isobaric partner around E x =18 MeV in 6He and 6Be. 相似文献
77.
Koutaro Shiraishi Hironobu Koseki Toshiyuki Tsurumoto Koumei Baba Mariko Naito Koji Nakayama Hiroyuki Shindo 《Surface and interface analysis : SIA》2009,41(1):17-22
Photocatalysis with anatase Titanium dioxide (TiO2) under ultraviolet A (UVA) has a well recognized bactericidal effect. There have been a few reports, however, on the effects of photocatalysis on bio‐implant‐related infections. The purpose of present study was to evaluate the photocatalytic bactericidal effects of anatase TiO2 on Staphylococcus aureus (S. aureus) associated with surgical site infections. TiO2 films were synthesized on commercially pure titanium substrates and SUS316 stainless steel using a plasma source ion implantation method followed by annealing. The chemical composition of the surface layers was determined using GXRD and XPS. The disks were seeded with cultured S. aureus and exposed to UVA illumination from black light. The bactericidal effect of the TiO2 films was evaluated by counting the survived colonies statistically. A structural gradient anatase type TiO2 layer formed on all substrates. The viability of the bacteria on the photocatalytic TiO2 film coated on titanium was suppressed to 7.0% at 30 minutes and 5.5% at 45 minutes, whereas that on a similarly coated stainless steel was suppressed to 45.8% at 30 minute and 28.6% at 45 minutes (ANOVA: p < 0.05). Complete bacterial inactivation was achieved after 90 minutes on titanium and after 60 minutes on stainless steel. The photocatalytic bactericidal effect of TiO2 is useful for sterilizing the contaminated surfaces of bioimplants. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
78.
A thermal method using differential scanning calorimeter has been applied to aqueous solutions of a series of poly(tetraalkylammonium ethenesulfonates) (R4NPES). It was found that only the salts withR=n-C4H9 andR=i-C5H11 could form stable hydrates having large hydration numbers. The melting point and hydration numbers of these two hydrates were 12.0°C and 30±1 for the (n-C4H9)4NPES hydrate and 16.0°C and 53±2 for the (i-C5H11)4NPES hydrate, respectively. It was concluded that these hydrates were clathrate-like essentially similar to such hydrates as (n-C4H9)4NF·30H2O and (i-C5H11)4NF·40H2O. 相似文献
79.
Gas transport properties of novel hyperbranched polyimide/hydroxy polyimide blends and their silica hybrid membranes were investigated. Gas permeability coefficients of the blend membranes showed positive deviation from a semilogarithmic additive rule. The enhanced gas permeability were resulted from the increase in free volume elements caused by the intermolecular interaction between terminal amine groups of the hyperbranched polyimide and hydroxyl groups of the hydroxy polyimide backbone. Additionally, CO2/CH4 separation ability of the blend membranes was markedly promoted by hybridization with silica. The remarkable CO2/CH4 separation behavior was considered to be due to characteristic distribution and interconnectivity of free volume elements created by the incorporation of silica. For the hyperbranched polyimide/hydroxy polyimide blend system, polymer blending and hybridization techniques synergistically provided the excellent CO2/CH4 separation ability. 相似文献
80.
Kimura H Nakayama Y Tsuchida A Okubo T 《Colloids and surfaces. B, Biointerfaces》2007,56(1-2):236-Optics
Rheological properties for Chinese ink in exhaustively deionized aqueous media were carefully examined. In the steady shear measurement, the shear viscosities of the ink could be well explained by considering the “effective” volume fraction of the particles in the ink including the electrical double layers and by using Einstein's equation for dilute suspension viscosity, when the particle volume fraction was substantially low. In the case that the volume fraction was higher, the shear viscosities showed extremely higher than those from Einstein's prediction, though the ink remained a Newtonian liquid. In the stress-strain measurement, the shear moduli were observed at strain smaller than 0.2. The “weak” aggregation among the particles in the ink under no shear or low shear rates was supported. It should be noted that the glue in the suspension plays an important role for the good liquidity of the ink and for the “weak” bridges among the particles resulting its good dispersion stability. 相似文献