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排序方式: 共有813条查询结果,搜索用时 31 毫秒
121.
Hassan Ghassemi Armaki Ruiping Chen Kouichi Maruyama Masaaki Igarashi 《Journal of Nuclear Materials》2011,416(3):273-279
There are two creep regions with different creep characteristics: short-term creep region “H”, where precipitates and subgrains are thermally stable, and long-term creep region “L”, where thermal coarsening of precipitates and subgrains appear. In region “H”, the normalized subgrain size (λ-λ0)/(λ∗-λ0) has a linear relation with creep strain and its slope is 10ε−1. But, region L is the time range in which the static recovery and the strain-induced recovery progress simultaneously. In this region, the static recovery accelerates the strain-induced recovery, and subgrain size is larger than that line which neglects the contribution of the static recovery. In region “L”, the Δλ/Δλ∗-strain present a linear relation with a slope 35ε−1. There is a linear relation between hardness and subgrain size. Hardness drop, H0 − H, as a function of Larson-Miller parameter can be a good measure method for assessment of hardness drop and consequently degradation of microstructure. Hardness drop shows an identical slope in creep region “H”, whereas hardness drop due to thermal aging and creep in region “L” show together a similar slope. In region “H”, degradation of microstructure is mainly due to recovery of subgrains controlled by creep plastic deformation, and precipitates do not have a major role. However, in creep region “L”, there are three degradation mechanisms that accelerate creep failure; (1) strain-induced recovery of subgrains due to creep plastic deformation, (2) static-recovery of subgrains and precipitates and (3) strain-induced coarsening of precipitates due to the appearance of static-recovery. 相似文献
122.
Beneficial Effects of Supplementation of the Rare Sugar “D‐allulose” Against Hepatic Steatosis and Severe Obesity in Lepob/Lepob Mice
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Kouichi Itoh Shodo Mizuno Sayuri Hama Wataru Oshima Miku Kawamata Akram Hossain Yasuhiro Ishihara Masaaki Tokuda 《Journal of food science》2015,80(7):H1619-H1626
A rare sugar, D‐allulose (also called D‐psicose), has recently been applied as a food supplement in view of controlling diabetes and obesity in Japan. D‐allulose has been proven to have unique effects against hyperglycemia and hyperlipidemia in a number of studies using several species of rats and mice. However, the antiobesity effects of D‐allulose have not yet been assessed in Lepob/Lepob (ob/ob) mice. Therefore, this study explored the dietary supplemental effects of this sugar in leptin‐deficient ob/ob mice. Consequently, the subchronic ingestion of D‐allulose in ob/ob mice for 15 wk significantly decreased the body and liver weights, and the loss of body weight was involved in the reduction of the total fat mass, including abdominal visceral fat, and not fat‐free body mass, including muscle. Furthermore, D‐allulose improved hepatic steatosis, as evaluated using hepatic histological studies and MRI. In the normal mice, none of these parameters were influenced by the single or long‐term ingestion of D‐allulose. These results indicate that dietary supplementation of D‐allulose especially influences postprandial hyperglycemia and obesity‐related hepatic steatosis, without exercise therapy or dietary restriction. Therefore, D‐allulose may be useful as a supplement for preventing and improving obesity and obesity‐related disorders. 相似文献
123.
Meng-Liang Lin Kenji Hara Yasuhiro Okubo Masaaki Yanagi Hironobu Nambu Atsushi Fukuoka 《Catalysis communications》2011,12(13):1228-1230
The olefin epoxidation is one of the most important reactions in chemical industry. Metal oxide supports often cause drawbacks in catalytic activity and selectivity, which has been overcome by introducing hydrophobic organic groups onto the oxide supports. The present study utilizes ordered mesoporous carbon (CMK-3 and CMK-1) as structurally defined hydrophobic catalyst support. Well-dispersed tantalum oxides supported on the ordered mesoporous carbon were prepared. Their application in catalytic epoxidation of cyclooctene demonstrates that the tantalum oxide catalysts on the ordered mesoporous carbon supports show higher performances than those of the catalysts supported on activated carbon and ordered mesoporous silica SBA-15. 相似文献
124.
Park JH Dias CA Lee SB Valentini SR Sokabe M Fraser CS Park MH 《Protein engineering, design & selection : PEDS》2011,24(3):301-309
Eukaryotic translation initiation factor 5A (eIF5A) is the only cellular protein that contains the polyamine-modified lysine, hypusine [N(ε)-(4-amino-2-hydroxybutyl)lysine]. Hypusine occurs only in eukaryotes and certain archaea, but not in eubacteria. It is formed post-translationally by two consecutive enzymatic reactions catalyzed by deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). Hypusine modification is essential for the activity of eIF5A and for eukaryotic cell proliferation. eIF5A binds to the ribosome and stimulates translation in a hypusine-dependent manner, but its mode of action in translation is not well understood. Since quantities of highly pure hypusine-modified eIF5A is desired for structural studies as well as for determination of its binding sites on the ribosome, we have used a polycistronic vector, pST39, to express eIF5A alone, or to co-express human eIF5A-1 with DHS or with both DHS and DOHH in Escherichia coli cells, to engineer recombinant proteins, unmodified eIF5A, deoxyhypusine- or hypusine-modified eIF5A. We have accomplished production of three different forms of recombinant eIF5A in high quantity and purity. The recombinant hypusine-modified eIF5A was as active in methionyl-puromycin synthesis as the native, eIF5A (hypusine form) purified from mammalian tissue. The recombinant eIF5A proteins will be useful tools in future structure/function and the mechanism studies in translation. 相似文献
125.
YoonKeun Chae JinWon Park Shinsuke Mori Masaaki Suzuki 《Korean Journal of Chemical Engineering》2013,30(1):62-66
The photocatalytic characteristics of partially reduced TiO2 (TiO2?x ) by plasma treatment and plasma-heated treatment were investigated in the visible-light region. For the visible-light photocatalytic activity of TiO2?x , plasmaheated treatment shows stronger than plasma treatment significantly. The TiO2?x by plasma-heated treatment shows broader red-shifted absorption bands than one by plasma treatment in the visible-light region. The surface color of TiO2?x by plasma treatment and plasma-heated treatment changed from white to sky blue, and to navy, respectively. After exposure to air, the surface color of TiO2?x changed from sky blue to white for plasma treatment and from navy to beige for plasma-heated treatment. 相似文献
126.
Katsuyoshi Matsuura Masaaki Nakabayashi Tetsuro Tamura Koichiro Honda Seigen Ohtani 《Integrated ferroelectrics》2013,141(2-4):139-149
Abstract PZT capacitor with direct contact between Si substrate and bottom electrode of the capacitor was obtained with Ir/IrO2/Ir/Ti electrode, by crystallizing sol-gel PZT thin film using RTA (650°CC 30 sec.). Contact resistance for hole diameter of 0.72 μm was 19 Ω. It was observed by cross-sectional TEM that Ti silicide was formed at the interface, but there was not oxygen diffusion from PZT thin film. Fatigue property of the PZT thin film was improved by RTA compared with furnace annealed film (600°CC 60 min.). The absolute value of the remnant polarization was 13 μC/cm2 for both films, but it did not degrade until 108 cycles of switching for the film by RTA, while it degraded before 105 cycles for furnace annealed film. 相似文献
127.
Tadao Shibuya Masahiro Yoshinaka Futoshi Utsuno Kazuyoshi Inoue Jung J. Kim Masaaki Obata 《Thin solid films》2010,518(11):3008-3011
The electronic structural analysis of the conductive transparent films was carried out using bulk sensitive hard X-ray photoelectron spectroscopy (HAXPES). The In2O3-ZnO film has amorphous structure before and after annealed, and the conduction band spectrum around Fermi level showed the similar spectra with that of as-deposited amorphous In2O3 film. In these amorphous films, the conduction band minimum locates at the deeper level than the crystalline In2O3 film. The electronic state which comes from randomness of amorphous structure possibly exists around this level or below. These electrons are expected to act as scattering center. We concluded that the electron mobility depends on the density of this electronic state. 相似文献
128.
Magnetite nanoparticles with high heating efficiencies for application in the hyperthermia of cancer
Zhixia Li Masakazu Kawashita Norio Araki Michihide Mitsumori Masahiro Hiraoka Masaaki Doi 《Materials science & engineering. C, Materials for biological applications》2010,30(7):990-996
Magnetic hyperthermia is a safe method for cancer therapy. A gap-type alternating current magnetic field (100 kHz, 100–300 Oe) is expected to be clinically applicable for magnetic hyperthermia. In this study, magnetite nanoparticles (MNPs) varying in size from 8 to 413 nm were synthesized using a chemical coprecipitation and an oxidation precipitation method to find the optimum particle size that shows a high heating efficiency in an applied magnetic field. The particles' in vitro heating efficiency in an agar phantom at an MNP concentration of 58 mg Fe/ml was measured in an applied magnetic field. In a magnetic field of 120 Oe, the temperature increase (ΔT) of the agar phantom within 30 s was 9.3 °C for MNPs with a size of 8 nm, but was less for the other samples, while in a magnetic field of 300 Oe, ΔT = 55 °C for MNPs with a size of 24 nm, and ΔT = 25 °C for MNPs with a size of 8 nm. The excellent heating efficiency of MNPs with a size of 24 nm in a magnetic field of 300 Oe may be due to a combination of the effects of both relaxation and hysteresis losses of the magnetic particles. It is believed that MNPs with a size of 8–24 nm will be useful for the in situ hyperthermia treatment of cancer. 相似文献
129.
130.
Ohtani Naoto; Haruki Mitsuru; Morikawa Masaaki; Kanaya Shigenori 《Protein engineering, design & selection : PEDS》2001,14(12):975-982
The rnhA gene encoding RNase HI from a psychrotrophic bacterium,Shewanella sp. SIB1, was cloned, sequenced and overexpressedin an rnh mutant strain of Escherichia coli. SIB1 RNase HI iscomposed of 157 amino acid residues and shows 63% amino acidsequence identity to E.coli RNase HI. Upon induction, the recombinantprotein accumulated in the cells in an insoluble form. Thisprotein was solubilized and purified in the presence of 7 Murea and refolded by removing urea. Determination of the enzymaticactivity using M13 DNARNA hybrid as a substrate revealedthat the enzymatic properties of SIB1 RNase HI, such as divalentcation requirement, pH optimum and cleavage mode of a substrate,are similar to those of E.coli RNase HI. However, SIB1 RNaseHI was much less stable than E.coli RNase HI and the temperature(T1/2) at which the enzyme loses half of its activity upon incubationfor 10 min was ~25°C for SIB1 RNase HI and ~60°C forE.coli RNase HI. The optimum temperature for the SIB1 RNaseHI activity was also shifted downward by 20°C compared withthat of E.coli RNase HI. Nevertheless, SIB1 RNase HI was lessactive than E.coli RNase HI even at low temperatures. The specificactivity determined at 10°C was 0.29 units/mg for SIB1 RNaseHI and 1.3 units/mg for E.coli RNase HI. Site-directed mutagenesisstudies suggest that the amino acid substitution in the middleof the 相似文献