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排序方式: 共有241条查询结果,搜索用时 15 毫秒
31.
Atsushi Kawano Kansuke Fukui Yuji Matsumoto Atsushi Terada Akihiro Tominaga Nozomi Nikaido Takashi Tonozuka Kazuhide Totani Nozomu Yasutake 《Journal of Applied Glycoscience》2020,67(2):41
According to whole-genome sequencing, Aspergillus niger produces multiple enzymes of glycoside hydrolases (GH) 31. Here we focus on a GH31 α-glucosidase, AgdB, from A. niger . AgdB has also previously been reported as being expressed in the yeast species, Pichia pastoris ; while the recombinant enzyme (rAgdB) has been shown to catalyze tranglycosylation via a complex mechanism. We constructed an expression system for A. niger AgdB using Aspergillus nidulans . To better elucidate the complicated mechanism employed by AgdB for transglucosylation, we also established a method to quantify glucosidic linkages in the transglucosylation products using 2D NMR spectroscopy. Results from the enzyme activity analysis indicated that the optimum temperature was 65 °C and optimum pH range was 6.0–7.0. Further, the NMR results showed that when maltose or maltopentaose served as the substrate, α-1,2-, α-1,3-, and small amount of α-1,1-β-linked oligosaccharides are present throughout the transglucosylation products of AgdB. These results suggest that AgdB is an α-glucosidase that serves as a transglucosylase capable of effectively producing oligosaccharides with α-1,2-, α-1,3-glucosidic linkages. 相似文献
32.
Makoto Ito Nam Ho Kim Nozomu Kogiso 《Structural and Multidisciplinary Optimization》2018,57(5):1919-1935
In this paper, a simple but efficient concept of epistemic reliability index (ERI) is introduced for sampling uncertainty in input random variables under conditions where the input variables are independent Gaussian, and samples are unbiased. The increased uncertainty due to the added epistemic uncertainty requires a higher level of target reliability, which is called the conservative reliability index (CRI). In this paper, it is assumed that CRI can additively be decomposed into the aleatory part (the target reliability index) and the epistemic part (the ERI). It is shown theoretically and numerically that ERI remains same for different designs, which is critically important for computational efficiency in reliability-based design optimization. Novel features of the proposed ERI include: (a) it is unnecessary to have a double-loop uncertainty quantification for handling both aleatory and epistemic uncertainty; (b) the effect of two different sources of uncertainty can be separated so that designers can better understand the optimization outcome; and (c) the ERI needs to be calculated once and remains the same throughout the design process. The proposed method is demonstrated with two analytical and one numerical examples. 相似文献
33.
Yao Zhang Takehumi Suga Mutsurou Kawasaki Xiao-Xia Tang Nozomu Uchida Keizo Uematsu 《Journal of the American Ceramic Society》1996,79(2):435-440
The effect of poly(vinyl alcohol) adsorption on segregation was quantitatively studied by a model experiment of one–dimension drying and simulated by a mathematical model. It was clear that the adsorption of PVA on alumina particle was a slow process, and the adsorbed binder was not desorbed at higher temperature. PVA segregation can significantly be limited by fully adsorbing the binder before drying. The simulation and experiments agreed very well. The effects of drying temperature, initial concentration of the binder, and thickness of specimen on the surface segregation are discussed quantitatively. Mathematical simulation has a great potential for predicting the segregation of soluble components during drying, especially for such cases as thin films and small granules where it is difficult to determine the distribution of the component directly. 相似文献
34.
Nozomu Takeuchi Mitsuharu Murase Yasuharu Nomura Haruto Takase Kiyohisa Uchida 《Lipids》1987,22(8):566-571
In order to investigate the effect of hepatic cholesterol flux on biliary bile acids, Triton WR 1339 and orotic acid were
administered to rats, and the biliary cholesterol, phospholipids and bile acids were analyzed together with serum lipoproteins
and hepatic lipids. Triton, which raised serum very low density lipoprotein and lipid levels and decreased serum high density
lipoprotein liver lipid levels, increase the biliary cholic acid group/chenodeoxycholic acid group ratio (CA/CDCA) in the
bile without affecting the total amount of bile acids and the other biliary lipids. Orotic acid, which decreased serum lipid
and lipoprotein concentrations and increased liver lipid levels, increased the biliary excretion of cholesterol and phospholipids,
but produced no significant change in the total amount of bile acids and in the CA/CDCA ratio in bile. 相似文献
35.
Keizo Uematsu Zenzi Kato Nozomu Uchida Katukazu Saito 《Journal of the American Ceramic Society》1987,70(7):142-C
High-purity and high-density tin dioxide doped with 1 × 1020 /cm3 antimony was prepared by hot isostatic pressing, and its electrical conductivity was measured over the temperature range 20° to 1200°C in various atmospheres. The conductivity decreased with increasing temperature and reached the value found in specimens normally sintered under the same conditions at normal pressure. The effect of microstructure on the carrier transport is discussed. Grain boundaries only slightly affect carrier transport at high temperatures. 相似文献
36.
Yasuaki Okamoto Hajime Nakano Takafumi Shimokawa Toshinobu Imanaka Shiichiro Teranishi 《Journal of Catalysis》1977,50(3):447-454
The promotional effects of Co in hydrodesulfurization (HDS) catalysts were studied by means of X-ray photoelectron spectroscopy. The higher MoO3-content catalysts (10 and 20 wt% MoO3) contain mobile Mo, which migrates from the pores to the outermost surface layers of the catalysts and segregates to form less active crystalline MoS2 during the HDS reaction, while in the case of (5 wt% MoO3) catalyst: no migration of Mo was observed. It is revealed that the Co in catalyst inhibits the migration and segregation of Mo and that it keeps Mo effective for the HDS reaction, since no surface enrichment of Mo was observed. It is concluded that stabilization of the Mo monomolecular layer is the main role of Co. The active species of Mo is suggested to have the composition of S/Mo(IV) = 1 on the basis of the sulfur contents of the catalysts under the mild HDS reaction conditions. 相似文献
37.
38.
One of the current issues in the peer-to-peer streaming systems is to supply sufficient upload bandwidth for continuous streaming of high-quality video channels. The helpers as upload bandwidth boosters can improve the streaming capacity of system, so that the imbalance of upload bandwidth between different video channel overlays is compensated. With the deployment of helpers as an intermediate level between server and peers, building and maintaining the optimal peer-helper topology becomes a challenging task since the one-directional nature of video streaming from the helpers to users makes the well-known reciprocity-based algorithms useless. Because of selfish behavior of peers and lack of a central authority among them, selection of helpers requires implicit coordination. In this paper, we design a decentralized, stochastic approximation helper selection mechanism which is adaptable to supply and demand pattern of various video channels. Our regret-tracking-based solution for allowing peers to strategically exploit their shared resources is guaranteed to converge to the correlated equilibria (CE) among the helper selection strategies. Online convergence to the set of CE is achieved through the regret-tracking algorithm which tracks the equilibrium in the presence of stochastic dynamics of helpers’ bandwidth. The resulting CE can help to select proper cooperation policies. Simulation results demonstrate that our algorithm achieves good convergence, load distribution on helpers and sustainable streaming rates for peers. 相似文献
39.
Sumitomo N Noritake K Hattori T Morikawa K Niwa S Sato K Niinomi M 《Journal of materials science. Materials in medicine》2008,19(4):1581-1586
In order to investigate bone tissue reaction to the low rigidity titanium alloy of TNTZ in bone plate fixation, animal experiment
with rabbit was performed with X-ray follow-up and histological observation. Experimental fractures were made in rabbit tibiae,
and fixed by different bone plates of SUS316L, Ti–6Al–4V and TNTZ. Although there was no significant difference in fracture
healing, bone atrophy was observed in cortical bone especially under the bone plate, which was different in time course among
three materials. The bone atrophy under the bone plate was confirmed as porous or poor bone tissue in histological observation.
In addition, the diameter of the tibia bone was increased in TNTZ as the result of bone remodeling with a new cortical bone.
It is confirmed that the elastic modulus of the bone plate will naturally influence bone tissue reaction to the bone plate
fixation according to the Wolff’s law of functional restoration. 相似文献
40.
The future high-temperature gas-cooled reactor (HTGR) is now designed in Japan Atomic Energy Agency. The reactor has many merging points of helium gas with different temperatures. It is needed to clear the thermal mixing characteristics of helium gas at the pipe in the HTGR from the viewpoint of structure integrity and temperature control. Previously, the reactor inlet coolant temperature was controlled lower than specific one in the high-temperature engineering test reactor (HTTR) due to lack of mixing of helium gas in the primary cooling system. Now, the control system is improved to use the calculated bulk temperature of reactor inlet helium gas. In this paper, thermal–hydraulic analysis on the primary cooling system of the HTTR was conducted to clarify the thermal mixing behavior of helium gas. As a result, it was confirmed that the thermal mixing behavior is mainly affected by the aspect ratio of annular flow path, and it is needed to consider the mixing characteristics of helium gas at the piping design of the HTGR. 相似文献