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71.
S Maruta Y Uyehara K Homma Y Sugimoto K Wakabayashi 《Canadian Metallurgical Quarterly》1999,125(1):177-185
The products of the SOS-regulated umuDC operon are required for most UV and chemical mutagenesis in Escherichia coli, a process that results from a translesion synthesis mechanism. The UmuD protein is activated for its role in mutagenesis by a RecA-facilitated autodigestion that removes the N-terminal 24 amino acids. A previous genetic screen for nonmutable umuD mutants had resulted in the isolation of a set of missense mutants that produced UmuD proteins that were deficient in RecA-mediated cleavage (J. R. Battista, T. Ohta, T. Nohmi, W. Sun, and G. C. Walker, Proc. Natl. Acad. Sci. USA 87:7190-7194, 1990). To identify elements of the UmuD' protein necessary for its role in translesion synthesis, we began with umuD', a modified form of the umuD gene that directly encodes the UmuD' protein, and obtained missense umuD' mutants deficient in UV and methyl methanesulfonate mutagenesis. The D39G, L40R, and T51I mutations affect residues located at the UmuD'2 homodimer interface and interfere with homodimer formation in vivo. The D75A mutation affects a highly conserved residue located at one end of the central strand in a three-stranded beta-sheet and appears to interfere with UmuD'2 homodimer formation indirectly by affecting the structure of the UmuD' monomer. When expressed from a multicopy plasmid, the L40R umuD' mutant gene exhibited a dominant negative effect on a chromosomal umuD+ gene with respect to UV mutagenesis, suggesting that the mutation has an effect on UmuD' function that goes beyond its impairment of homodimer formation. The G129D mutation affects a highly conserved residue that lies at the end of the long C-terminal beta-strand and results in a mutant UmuD' protein that exhibits a strongly dominant negative effect on UV mutagenesis in a umuD+ strain. The A30V and E35K mutations alter residues in the N-terminal arms of the UmuD'2 homodimer, which are mobile in solution. 相似文献
72.
Ken’ichiro Kita Masaki Narisawa Atsushi Nakahira Hiroshi Mabuchi Masayoshi Itoh Masaki Sugimoto Masahito Yoshikawa 《Journal of Materials Science》2010,45(1):139-145
The polymer blends of PCS (polycarbosilane) and PMHS-h (polymethylohydrosiloxane with high molecular weight) were prepared
by freeze-drying process of mixed benzene solution. Melt viscosity, mass loss, and gas evolution from prepared polymer blends
were analyzed. A polymer blend of HSah15 (15 mass% PMHS-h to PCS) was melt-spun to fiber form, curing by thermal oxidation
and pyrolyzed at various temperatures up to 1773 K. The obtained fibers were investigated by tensile tests, FE-SEM (field
emission scanning electron microscope) observation, and XRD (X-ray diffraction) analysis. After pyrolysis at 1273 K, there
were no pores in the cross section of the fiber derived from pure PCS; however, there were amounts of pores in the cross sections
of the fiber derived from HSah15. After pyrolysis at 1773 K, the coarse β-SiC (silicon carbide) crystals were formed on the
outside surface of the fiber derived from pure PCS; however, no remarkable β-SiC crystal were formed on the outside surface
of the fiber derived from HSah15. 相似文献
73.
The dissociation ratio of source gas molecules is measured using a quartz sensor, for which the output depends on the average molecular weight and viscosity of gases. The change in the pressure and temperature-normalized quartz sensor output (NQO) by discharge correlates with changes of the signal intensity of the source gas of ammonia (NH3), as measured by gas analysis using a quadrupole mass spectrometer. Thereby, the dissociation ratio is obtainable from the change in NQO by the discharge. The spatial distributions of the change in NQO in the plasma chamber show a larger change in NQO near the plasma electrode, indicating that the change in NQO correlates with the dissociation ratio of NH3. Finally, the dissociation ratios of NH3 near and between the plasma electrodes were obtained from the spatial distribution of the dissociation ratio of NH3. Results show that the Q-sensor measurement is simple and useful to derive the dissociation ratio of the source gases for the plasmas of reactive gases. 相似文献
74.
Hongo Takero Arakawa Hideo Sugimoto Gunji Tange Koichi Yamamoto Yuzo 《Industrial Electronics, IEEE Transactions on》1987,(1):5-10
An automatically guided vehicle, traveling without fixed guide ways, has been developed. In this paper, the construction of the vehicle, the control algorithm, and its general performance are described. 相似文献
75.
Shigeki Tasaka Yoshihiro Sato Nobuhito Tateyama Hisahiko Sugimoto Fumihito Fumuro Kaoru Hoshino 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1985,236(2):400-409
A new multiple scanning method is developed and applied to detect cosmic heavy nuclei. The plastic track detectors CR-39 exposed to cosmic heavy nuclei are over-etched in 8.0N NaOH for 94 h at 80°C. We found that the etched cones can easily be scanned on the plastic plates without using an optical microscope. The trajectories of heavy nuclei can be reconstructed with the naked eyes by superposing four or more over-etched plates. The charge detection threshold is obtained by this method, and appears to be 10. The charge resolution is estimated to be 1.0 charge units for iron nuclei. By adopting this method, the scanning time is much shortened and CR-39 plastic chamber size can easily be scaled up. The method is very useful for detecting particles with low flux intensity, like for searching magnetic monopoles or for measuring the high energy spectra of cosmic heavy nuclei. 相似文献
76.
77.
Xunwen Xiao Jianghua Fang Jin Zhou Haoqi Gao Hideki Fujiwara Toyonari Sugimoto 《Synthetic Metals》2010,160(23-24):2413-2416
Crystal structure, and electrical conducting and magnetic properties of a radical cation salt of EDO-TTFVODS with magnetic FeCl4? ion, (EDO-TTFVODS)2FeCl4 (EDO-TTFVODS = ethylenedioxytetrathiafulvalenoquinone-1,3-diselenolemethide) are reported. In this salt, there are two independent donor molecules formed two different layers A and B, and the counter FeCl4? ions layer is sandwiched between two donor layers A and B along the b-axis. The donor molecules form the one-dimensional columns along the a-axis in both donor layers. This salt shows high conductivity at room temperature (σRT = 25 S cm?1) and a metallic behavior down to ca. 80 K, where a metal–insulator transition however occurs. The magnetic susceptibility obeys a Curie–Weiss law (Curie constant C = 4.42 emu K mol?1 and Weiss temperature Θ = ?1.5 K), without any magnetic ordering down to 1.8 K. This result suggests the weak antiferromagnetic interaction between the d spins of FeCl4? ions. 相似文献
78.
79.
K Sakamoto M Arakawa M Ohmori K Sugimoto A Fujimura 《Canadian Metallurgical Quarterly》1997,61(13):1253-1259
The daily variation in an intensity of kaolin-induced writhing reaction was examined in mice kept under conditions of light; 07:00 - 19:00 and dark; 19:00 - 07:00. The number of writhes was counted for 30 minutes after a single intraperitoneal injection of kaolin at 00:00, 02:00, 04:00, 06:00, 08:00, 10:00, 12:00, 14:00, 16:00, 18:00, 20:00 and 22:00. The number of writhes showed a daily variation with a peak at 18:00 and a trough at 06:00. The intensity of writhing reaction was significantly reduced by pretreatment with the bradykinin B1 (Des-Arg9-[Leu8]-BK) and B2 (icatibant) receptor antagonists. Significant daily variation in this parameter was still observed in the group with the B1 antagonist, but disappeared in the B2 antagonist-treated group. These results suggest that the kaolin-induced writhing reaction shows the daily variation with a peak at the end of the resting period and a trough at the end of the active period. The B2 receptor mediated stimuli appears to be involved in this phenomenon. 相似文献
80.
Rong-Jun Xie Naoto Hirosaki Mamoru Mitomo Takayuki Suehiro Xin Xu Hidehiko Tanaka 《Journal of the American Ceramic Society》2005,88(10):2883-2888
Rare-earth-doped Ca-α-SiAlON phosphors, with the compositions of (Ca1−3/2 x RE x ) m /2 Si12− m − n Al m+n O n N16− n (RE=Ce, Sm, and Dy, 0.5≤ m =2 n ≤3.0), were prepared by sintering at 1700°C for 2 h under 10 atm N2 . The concentration of rare earths varied from 3 to 30 at.% with respect to Ca. The photoluminescence (PL) properties were investigated as functions of the composition of the host matrix (i.e., m ) and the concentration of rare earths (i.e., x ). The results show that the emission properties can be optimized by tailoring m and x . The Ce3+ luminescence originating from the 4 f –5 d interconfigurational transitions is greatly affected by the environment surrounding the Ce3+ ions, which differs from the Sm3+ or Dy3+ luminescence arising from the 4 f –4 f intraconfigurational transitions. X-ray diffraction and scanning electron microscopy were used to explain the composition and concentration dependence of PL properties. 相似文献