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1.
Prof. Hiroshi Watanabe Ming-Long Yao Atsuko Yamagishi Kunihiro Osaki Toshiyuki Shitata Hirokazu Niwa Yotaro Morishima 《Rheologica Acta》1996,35(5):433-445
Linear and nonlinear viscoelastic properties were examined for a 50 wt% suspension of spherical silica particles (with radius of 40 nm) in a viscous medium, 2.27/1 (wt/wt) ethylene glycol/glycerol mixture. The effective volume fraction of the particles evaluated from zero-shear viscosities of the suspension and medium was 0.53. At a quiescent state the particles had a liquid-like, isotropic spatial distribution in the medium. Dynamic moduli G* obtained for small oscillatory strain (in the linear viscoelastic regime) exhibited a relaxation process that reflected the equilibrium Brownian motion of those particles. In the stress relaxation experiments, the linear relaxation modulus G(t) was obtained for small step strain (0.2) while the nonlinear relaxation modulus G(t, ) characterizing strong stress damping behavior was obtained for large (>0.2). G(t, ) obeyed the time-strain separability at long time scales, and the damping function h() (–G(t, )/G(t)) was determined. Steady flow measurements revealed shear-thinning of the steady state viscosity () for small shear rates (< –1; = linear viscoelastic relaxation time) and shear-thickening for larger (>–1). Corresponding changes were observed also for the viscosity growth and decay functions on start up and cessation of flow, + (t, ) and – (t, ). In the shear-thinning regime, the and dependence of +(t,) and –(t,) as well as the dependence of () were well described by a BKZ-type constitutive equation using the G(t) and h() data. On the other hand, this equation completely failed in describing the behavior in the shear-thickening regime. These applicabilities of the BKZ equation were utilized to discuss the shearthinning and shear-thickening mechanisms in relation to shear effects on the structure (spatial distribution) and motion of the suspended particles.Dedicated to the memory of Prof. Dale S. Parson 相似文献
2.
Fumiko Fujisaki Sachi Hiromatsu Yumiko Matsumura Aki Fukami Nobuhiro Kashige Fumio Miake Kunihiro Sumoto 《Journal of heterocyclic chemistry》2013,50(2):417-424
In connection with our studies on antibacterial active compounds in the class of new oxazolidinones against Gram‐positive (Staphylococcus aureus) and Gram‐negative (Escherichia coli) strains, some molecular modifications were attempted. In this study, molecular modifications of 4‐aminomethyloxazolidin‐2‐ones ( 3a ) to the corresponding 4‐acylaminomethyloxazolidin‐2‐one derivatives ( 3c–d ) and preparations of the represented twin‐drug type molecules ( 10–14 ) were investigated. Some additional 4‐dialkylaminomethyloxazolidin‐2‐ones ( 2 ) were also synthesized. The synthesized compounds were evaluated for antibacterial activity with Gram‐positive (S. aureus) and Gram‐negative (E. coli) strains. 相似文献
3.
Makoto Kunisada Taro Masaki Ryusuke Ono Hironobu Morinaga Eiji Nakano Flandiana Yogianti Kunihiro Okunishi Hiroshi Sugiyama Chikako Nishigori 《Photochemistry and photobiology》2013,89(3):649-654
The UVA is currently thought to be carcinogenic because, similar to UVB, it induces the formation of cyclobutane pyrimidine dimers (CPDs). Various drugs have been reported to cause photosensitive drug eruptions as an adverse effect. Although the precise mechanism of photosensitive drug eruption remains to be elucidated, it is generally accepted that free radicals and other reactive molecules generated via UV‐irradiated drugs play important roles in the pathogenesis of photosensitive drug eruptions. The waveband of concern for photo‐reactive drugs is UVA‐visible light, but some extend into the UVB region. We tested whether photosensitive drugs could enhance CPD formation after UVA exposure by using isolated DNA in the presence of several reported photosensitive drugs using high‐performance liquid chromatography. We found that the diuretic agent hydrochlorothiazide (HCT) significantly enhanced the production of TT dimers over a wide range of UVA. Furthermore, we investigated whether UVA plus HCT could enhance CPD production in xeroderma pigmentosum model mice defective in nucleotide excision repair. Immunofluorescence studies showed that CPD formation in the skin significantly increased after 365 nm narrow‐band UVA irradiation in the presence of HCT, compared with that in wild‐type mice. HCT could be used with caution because of its enhancement of UVA‐induced DNA damage. 相似文献
4.
5.
Strahil Iv. PASTUHOV Naoki HISAMOTO Kunihiro MATSUMOTO 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2015,91(3):63-75
Mitogen-activated protein kinase (MAPK) signaling cascades are activated by diverse stimuli such as growth factors, cytokines, neurotransmitters and various types of cellular stress. Our evolving understanding of these signal cascades has been facilitated by genetic analyses and physiological characterization in model organisms such as the nematode Caenorhabditis elegans. Genetic and biochemical studies in C. elegans have shed light on the physiological roles of MAPK cascades in the control of cell fate decision, neuronal function and immunity. Recently it was demonstrated that MAPK signaling is also important for axon regeneration in C. elegans, and the use of C. elegans as a model system has significantly advanced our understanding of the largely conserved molecular mechanisms underlying axon regeneration. This review summarizes our current understanding of the role and regulation of MAPK signaling in C. elegans axon regeneration. 相似文献
6.
We propose a fundamental interconnection method using a polarization alignment system for waveguides having different spatial
modes. In addition, as an example for the verification of the fundamental operation, we demonstrate an interconnection between
a photonic crystal fiber and a laser that have obviously different spatial modes. The polarization alignment system operates
synergistically with a self-written waveguide formed with a double phaseconjugate mirror. This technique enables us to interconnect
a photonic crystal fiber with a laser source without complicated and time-consuming optical alignment. In this method, although
it is not necessary to perform an external control for interconnection, the waveguide most suitable for connection is formed
autonomously in a Sn2P2S6:Sb crystal developed for this purpose. There was a marked reduction in the polarization dependence of coupling efficiency,
compared with that observed using a stand-alone double phase-conjugate mirror. 相似文献
7.
K. Hirose M. Ejima T. Fujibayashi Y. Fujii K. Futatsukawa O. Hashimoto T. Ishikawa S. Kameoka H. Kanda F. Kato S. Kinoshita T. Kinoshita T. Kon O. Konno K. Maeda A. Matsumura Y. Miura F. Miyahara H. Miyase T. Nakabayashi S.N. Nakamura H. Nomura K. Nonaka A. Ohtani Y. Okayasu M. Oyamada A. Sasaki H. Shimizu T. Takahashi T. Tamae H. Tamura T. Terasawa H. Tsubota K. Tsukada D. Uchida M. Ukai M. Wakamatsu T. Watanabe H. Yamauchi H. Yamazaki K. Yawata 《Physics letters. [Part B]》2009
8.
9.
We propose a stable first-order relativistic dissipative hydrodynamic equation in the particle frame (Eckart frame) for the first time. The equation to be proposed was in fact previously derived by the authors and a collaborator from the relativistic Boltzmann equation. We demonstrate that the equilibrium state is stable with respect to the time evolution described by our hydrodynamic equation in the particle frame. Our equation may be a proper starting point for constructing second-order causal relativistic hydrodynamics, to replace Eckart's particle-flow theory. 相似文献
10.
Casting a photopolymer solution to form a film, followed by imagewise photoirradiation and subsequent wet development, leads to photolithography. Whereas the wet development is achievable with aqueous alkali, the emission of an organic solvent as a volatile organic compound (VOC) is usually inevitable during the film casting because ingredients of common photopolymers are insoluble in water. We show here a prototype of water‐borne photopolymers dispersed with milled nanoparticles of poorly water‐soluble photoacid generators (PAGs), which undergo solid‐state photolysis to liberate a photoacid to make a poly(vinyl alcohol) film insoluble in water with the aid of an acid‐sensitive crosslinking reagent. The photolysis of onium‐type PAGs is sensitized in the solid state simply by comilling with water‐insoluble sensitizers to extend spectral sensitivity of this kind of photopolymers. Fluorescence quenching measurements revealed that the solid‐state sensitization occurs through exciton migration in sensitizer particles followed by electron transfer to PAG particles.