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71.
Hiromichi Akahori Stéphane Guindon Sumio Yoshizaki Yoshinori Muto 《International journal of molecular sciences》2015,16(12):28472-28485
Ten-eleven translocation (TET) proteins, a family of Fe2+- and 2-oxoglutarate-dependent dioxygenases, are involved in DNA demethylation. They also help regulate various cellular functions. Three TET paralogs have been identified (TET1, TET2, and TET3) in humans. This study focuses on the evolution of mammalian TET genes. Distinct patterns in TET1 and TET2 vs. TET3 were revealed by codon-based tests of positive selection. Results indicate that TET1 and TET2 genes have experienced positive selection more frequently than TET3 gene, and that the majority of codon sites evolved under strong negative selection. These findings imply that the selective pressure on TET3 may have been relaxed in several lineages during the course of evolution. Our analysis of convergent amino acid substitutions also supports the different evolutionary dynamics among TET gene subfamily members. All of the five amino acid sites that are inferred to have evolved under positive selection in the catalytic domain of TET2 are localized at the protein’s outer surface. The adaptive changes of these positively selected amino acid sites could be associated with dynamic interactions between other TET-interacting proteins, and positive selection thus appears to shift the regulatory scheme of TET enzyme function. 相似文献
72.
Fatigue behaviour was investigated for low-strength silica fibres on which macroscopic flaws were forcibly introduced by abrading. Crack growth in silica glass was also examined on the CT specimen. Stable crack growth parameters, obtained from the static and dynamic fatigue tests for abraded fibres, were determined to be about 40 which is equal to that obtained from the CT specimen, indicating that the crack growth process in abraded fibres is quite the same as in the CT specimen. This leads to the conclusion that, for the optical fibre, the allowable stress condition wherein no breaks occur is given on the basis of some basic fracture mechanics parameters obtained from the CT specimen. 相似文献
73.
74.
Wakako Araki Yoshinori Imai Tadaharu Adachi 《Journal of the European Ceramic Society》2009,29(11):2275-2279
In the present study, the effect of mechanical tensile stress on oxygen mobility in 8 mol% yttria-stabilized zirconia (8YSZ) was investigated. The experimental results show that the ionic conductivity increases with stress and saturates. The maximum improvement in the conductivity was about 18% observed at 973 K. The simulation results show that the diffusion coefficient increases with stress and decreases with excessive stress. The maximum improvement was about 40% observed at 973 K. The improvement was larger at lower temperatures in both the experiment and the simulation. The strain caused by the stress is considered to have caused the gradient in the potential energies of the neighbouring oxygen sites, especially around the yttrium ions, which probably facilitated the migration of the oxygen ions. 相似文献
75.
Toshihiro Hiejima Yosuke Takamizawa Yoshinori Tanaka Kenji Ueda Takayuki Uchida 《Synthetic Metals》2009,159(9-10):986-989
The characteristics of EL devices containing α-helical poly(l-glutamate) and having a carbazole side chain (PCELG) were found to strongly depend on the casting solvents. Among EL devices fabricated using chlorine-containing casting solvents such as 1,2-dichloroethane (DCE), 1,1,2,2-tetrachloroethane (TCE), chloroform (CHCl3), and monochlorobenzene (?-Cl), the EL device fabricated using the DCE solvent exhibited the maximum luminance (65.8 cd/m2). The difference between the threshold voltages of the devices ranged up to 6.0 V, despite their fabrication by using solutions with the same composition ratio. The maximal efficiency of the devices fabricated using the DCE solvent was found to be 20 times greater than that of the devices fabricated using TCE solvents. A comparison of the current densities and voltages among devices fabricated using different casting solvents at their maximal efficiencies showed that the maximal efficiencies tended to significantly increase in the order TCE < CHCl3 < DCE solvents at similar voltages (~15 V), despite a lowering of the current density. The current density was considered to be directly related to the number of carriers injected into the device. The above-mentioned observations suggested that the maximal efficiency in these devices was not the hole and electron injection efficiencies, but the values of some parameters subsequent to carrier injection, such as the recombination rate, amount of excitons generated, and the diffusion length. 相似文献
76.
Randeep Rakwal Ganesh Kumar Agrawal Junko Shibato Tetsuji Imanaka Satoshi Fukutani Shigeru Tamogami Satoru Endo Sarata Kumar Sahoo Yoshinori Masuo Shinzo Kimura 《International journal of molecular sciences》2009,10(3):1215-1225
We report molecular changes in leaves of rice plants (Oryza sativa L. - reference crop plant and grass model) exposed to ultra low-dose ionizing radiation, first using contaminated soil from the exclusion zone around Chernobyl reactor site. Results revealed induction of stress-related marker genes (Northern blot) and secondary metabolites (LC-MS/MS) in irradiated leaf segments over appropriate control. Second, employing the same in vitro model system, we replicated results of the first experiment using in-house fabricated sources of ultra low-dose gamma (γ) rays and selected marker genes by RT-PCR. Results suggest the usefulness of the rice model in studying ultra low-dose radiation response/s. 相似文献
77.
Yoshinori Nishida Norihisa Izawa Yukio Kuramasu 《Metallurgical and Materials Transactions A》1999,30(3):839-844
Separation of matrix metals in composites was tried on alumina short fiber-reinforced aluminum and 6061 alloy composites and
SiC whisker-reinforced 6061 alloy composite for recycling. It is possible to separate molten matrix metals from fibers in
the composites using fluxes that are used for melt treatment to remove inclusions. About 50 vol pct of the matrix metals was
separated from the alumina short fiber-reinforced composites. The separation ratio of the matrix from the SiC whisker-reinforced
6061 alloy composite was low and about 20 vol pct. The separation mechanism was discussed thermodynamically using interface
free energies. Since the flux/fiber interface energy is smaller than the aluminum/fiber interface energy, the replacement
of aluminum with fluxes in composites takes place easily. Gases released by the decomposition of fluxes act an important role
in pushing out the molten matrix metal from the composite. The role was confirmed by the great amount cavity formed in the
composite after the matrix metal flowed out. 相似文献
78.
Sanae Shimizu Kazuhiko Yamamoto Caihau Wang Yutaka Satoh Hideki Tanahashi Yoshinori Niwa 《Electrical Engineering in Japan》2005,152(3):29-38
Moving object detection with a mobile image sensor is an important task in robotics and computer vision, when considering the practical use of robotics in human environments. In this paper, we propose a robust method that detects moving objects in the environment using the omnidirectional depth information obtained by a mobile Stereo Omnidirectional System (SOS). In order to detect only the moving objects within the depth image that are obtained by a sensor in motion, we first estimate the ego‐motion of the sensor, and generate a predicted depth image for the current time from the depth obtained at the previous time by only considering the ego‐motion of the sensor. Then the predicted depth image is compared with the actual one obtained at the current time, and the inconsistent regions are detected as moving objects. When the sensor moves, occlusions will occur in the scene and they will cause false detections. However, these false detections can be suppressed by estimating the occlusion regions using the ego‐motion parameters of the sensor and the jump edges in the depth image. The effectiveness of the method is shown with experimental results for a real environment. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(3): 29–38, 2005; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.20155 相似文献
79.
Masahiko Hirao Hidekazu Fukuoka Yoshinori Murakami 《Research in Nondestructive Evaluation》1992,4(3):127-138
A computer-driven, swept-frequency measurement technique is developed on the basis of resonance birefringence acoustoelasticity to evaluate the stresses in thin plates. The resonance frequency depends on the thickness and the elastic wave velocity; they change with stress because of the Poisson effect and the acoustoelastic effect. The resonance frequency is obtained from the spectral response curve in the electric impedance of the piezoelectric transducer. The frequency displacement induced by acoustically coupling the transducer can be minimized by employing the resonance peak closest to the transducer fundamental frequency. To illustrate the method, the residual stress is measured in butt-welded aluminum alloy plates and is compared with the results of conventional methods. 相似文献
80.
Shigeaki Abe Yoshinori Nagoya Fumio Watari Hiroto Tachikawa 《Computational Materials Science》2011,50(9):2640-2643
The evaporation processes of water molecules adsorbed in the edge region of graphene have been investigated by means of direct MO–MD method. A large system composed of 29 water molecules and a graphene sheet (C96H24) was used as a model system. The edge carbon atom of graphene was terminated by hydrogen atom. The geometry optimization showed that the water molecules interact with the hydrogen atoms in the edge region of graphene. At low temperature (300 K), the water molecules were dissociated as water clusters from the graphene. On the other hand, in addition to the dissociation of water clusters, the isolated water molecule was also found as dissociation product at high temperature (500 K). The mechanism of water evaporation was discussed on the basis of theoretical results. 相似文献