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1.
Properties and applications of β‐glycosidase from Bacteroides thetaiotaomicron that specifically hydrolyses isoflavone glycosides
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Da‐Hye Byun Hye‐Jeong Choi Hye‐Won Lee Hye‐Yeon Jeon Woo‐Jae Choung Jae‐Hoon Shim 《International Journal of Food Science & Technology》2015,50(6):1405-1412
To modify the glycan part of glycosides, the gene encoding β‐glycosidase was cloned from Bacteroides thetaiotaomicron VPI‐5482. The cloned gene, bt_1780, was expressed in Escherichia coli MC1061 and the expressed enzyme was purified using Ni‐NTA affinity chromatography. The purified enzyme, BTBG, showed optimal activity at 50 °C and pH 5.5. Interestingly, this enzyme did not have any hydrolysing activity on ordinary β‐linkage–containing substrates such as xylobiose, lactose and cello‐oligosaccharide, but specifically hydrolysed isoflavone glycosides such as daidzin, genistin and glycitin. Compared to a commercial beta glucosidase, BTBG selectively hydrolysed isoflavone glycosides in soybean extract mixture solution. These results suggest that BTBG may be a specialized enzyme for the hydrolysis of glycosides and that the substrate specificity of BTBG is applicable for the bioconversion of isoflavone glycosides in the food industry. 相似文献
2.
PURPOSE: This article describes a vascularized bony window for access to the maxillary sinus and reports the clinical results. PATIENTS AND METHODS: A bony U-shaped window in the anterior sinus wall was pedicled on the surrounding soft tissue and periosteum. After the described sinus was cleared of disease, the window was repositioned in its original site either using resorbable sutures or not. The method was used in 47 maxillary sinus operations in 45 patients. Twenty-four patients were followed-up for more than 48 months. RESULTS: The vascularized bony window technique showed uneventful healing in all patients and none of the 24 patients reported any problems. CONCLUSIONS: The vascularized bony window technique provides a large antrostomy, which gives good access and visibility and results in satisfactory postoperative healing. 相似文献
3.
In recent years, the topic of knowledge production has been widely investigated in the advanced countries. However, the process
by which knowledge is produced in the developing countries has not been fully explored or characterized. In Korea, the science
and engineering fields strongly reflect systems of knowledge production in the universities and demonstrate the dynamics of
systems of innovation for knowledge production. Through using a case study including data for knowledge production, in the
field of information and telecommunication, the following general trends were observed. Firstly, there has been a trend towards
increasing the capabilities for knowledge production, via domestic and foreign collaboration. Secondly, there has been an
increasing trend towards the diversification of knowledge sources such as university-industry, and university-public research
institutes. Finally, the establishment of a nation's knowledge base is influenced by governmental research and development
policies.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
4.
Numerical prediction of the wind flow and pollutant dispersion over two-dimensional hilly terrain is presented. The wind tunnel
experiments are conducted to validate the numerical results of the flow field. Measured mean velocity profiles, turbulence
characteristics, and surface pressure distributions show good agreement with the numerical predictions. The hypothesis of
Reynolds number independency for an atmospheric boundary layer flow over aerodynamically rough terrain is numerically confirmed.
The linear theory provides generally good prediction of speed-up characteristics for gently sloped low hills. The effect of
two-dimensional double hills on the dispersion of pollutants from continuously or temporally released line source of different
emission heights and locations is also investigated. The ground-level concentrations are considerably reduced as emission
heights are increased. The variances of ground-level concentration with respect to time from a temporally released source
are strongly influenced by the flow separation. 相似文献
5.
Sanja Dogramadzi Maria Elena Giannaccini Christopher Harper Mohammad Sobhani Roger Woodman Jiyeon Choung 《Journal of Intelligent and Robotic Systems》2014,76(1):73-117
Robot manufacturers will be required to demonstrate objectively that all reasonably foreseeable hazards have been identified in any robotic product design that is to be marketed commercially. This is problematic for autonomous mobile robots because conventional methods, which have been developed for automatic systems do not assist safety analysts in identifying non-mission interactions with environmental features that are not directly associated with the robot’s design mission, and which may comprise the majority of the required tasks of autonomous robots. In this paper we develop a new variant of preliminary hazard analysis that is explicitly aimed at identifying non-mission interactions by means of new sets of guidewords not normally found in existing variants. We develop the required features of the method and describe its application to several small trials conducted at Bristol Robotics Laboratory in the 2011–2012 period. 相似文献
6.
A new approach to the design of a neural network (NN) based navigator is proposed in which the mobile robot travels to a pre-defined
goal position safely and efficiently without any prior map of the environment. This navigator can be optimized for any user-defined
objective function through the use of an evolutionary algorithm. The motivation of this research is to develop an efficient
methodology for general goal-directed navigation in generic indoor environments as opposed to learning specialized primitive
behaviors in a limited environment. To this end, a modular NN has been employed to achieve the necessary generalization capability
across a variety of indoor environments. Herein, each NN module takes charge of navigating in a specialized local environment,
which is the result of decomposing the whole path into a sequence of local paths through clustering of all the possible environments.
We verify the efficacy of the proposed algorithm over a variety of both simulated and real unstructured indoor environments
using our autonomous mobile robot platform. 相似文献
7.
Byeong-Seon Shin Sang-Yun Lim Suk-Jin Choung 《Korean Journal of Chemical Engineering》1994,11(4):254-260
As an attempt to improve the catalytic activity at higher reaction temperatures between 300-450°C, various mole ratios of
WO3 were added to V2O5/TiO2 catalytic systems. And also, in order to suggest a new mixed oxide catalyst system for simultaneous removal of NOx and SOx, from stationary sources, MoO3-V2O5/TiO2catalysts were prepared by a conventional impregnation method together with a newly introduced method of surface fixation
(non-aqueous solution method). In case of WO3 addition, at higher reaction temperature range (300–450°C), WO3 and WO3-V2O5/TiO2 catalysts showed significant high conversion in NO reduction with NH3 while V2O5/TiO2 catalyst showed a significant change in selectivity mainly due to the excess side reaction of NH3 oxidation. This difference in selectivity due to NH3 oxidation at high temperature is supposed to be associated with the difference in values of surface excess oxygen between
WO3 and V2O5 on titania. The surface acidities of tested catalysts were relatively well correlated with the % conversion of NO at 400°C.
In case of MoO3 addition, the catalytic activity for the simultaneous removal of NOx and SOx were quite enhanced by the addition of MoO3 into V2O5/TiO2 catalysts. The enhanced activities were responsible for the formation of Mo=O bond on the intermediate species produced by
solid solutions on MoO3-V2O5/TiO2 (aqueous). However, in the case of MoO3-V2O5/TiO2 (non-aqueous), the exact source of active site was not able to detect in IR spectra in spite of more enhanced activity was
obtained in this study. After SO2 contact, VOSO4 is newly formed on the surface of catalyst, which supposed to be associated with the activity enhancement. 相似文献
8.
Seok Cho Se-Young Chun Sang-Ki Moon Won-Pil Baek Yoo Kim 《Nuclear Engineering and Design》2005,235(1):77-90
KAERI has performed an experimental study on the critical heat flux (CHF) under zero flow conditions with a non-uniformly heated 3 × 3 rod bundle. Experimental conditions are in the range of a system pressure from 0.50 to 14.96 MPa and inlet water subcooling enthalpies from 68 to 352 kJ/kg. The test section used in the present experiments consisted of a vertical flow channel, upper and lower plenums, and a non-uniformly heated 3 × 3 rod bundle. The experimental results show that the CHFs in low-pressure conditions are somewhat scattered within a narrow range. As the system pressure increases, however, the CHFs show a good parametric trend. The CHFs occur in the upper region of the heated section, but the locations of the detected CHFs move gradually in a downward direction with the increase of the system pressure. Even though the effects of the inlet water subcooling enthalpies and system pressure of the flooding CHF are relatively smaller than those of the flow boiling CHF, the CHF increases by increasing the inlet water subcooling enthalpies. Several existing correlations for the countercurrent flooding CHF based on Wallis's flooding correlation and Kutateladze's criterion for the onset of flooding are compared with the CHF data obtained in the present experiments to examine the applicability of the correlations. 相似文献
9.
Preparation and optimisation of liposome‐in‐alginate beads containing oyster hydrolysate for sustained release
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Cheng‐liang Xie Su‐Seon Lee Se‐young Choung Sang Soo Kang Yeung Joon Choi 《International Journal of Food Science & Technology》2016,51(10):2209-2216
Oyster (Crassostrea gigas) hydrolysate shows antihypertensive effect in our previous study. Oral administration of oyster hydrolysate can loss bioactive peptides due to enzymatic degradation in vivo. To maximise its bioavailability, liposome‐in‐alginate (LA) beads were used to encapsulate the oyster hydrolysates to protect from degradation and obtain sustained release. The preparation conditions of the LA beads were optimised by response surface method using a model peptide of tyrosylalanine (YA). Their characterisation, swelling and release properties were investigated. The optimised conditions for the concentration of calcium chloride, sodium alginate and the amount of ethanol‐dissolved lecithin (EDL) were 0.5 m , 3% and 95.4 mg, respectively. The encapsulation efficiencies of YA and the oyster hydrolysate in the optimised condition were 74.9% and 84.3%, respectively. The release time of the oyster hydrolysate in the simulated gastrointestinal fluid was up to 16 h. The LA beads can be recommended to encapsulate oyster hydrolysate for bioavailability improvement. 相似文献
10.
A Mo/TiN composite powder has been synthesized by a sol–gel method to improve the electrical performance and microstructural stability of the alkali metal thermal to electric converter electrode. The core (TiN)–shell (Mo) structure of the composite powder is confirmed by energy-dispersive X-ray spectroscopy and scanning electron microscopy. The composite powder is primarily composed of submicron (400–800 nm) particles that are coated on a core (>3–5 μm) particle. The Mo/TiN composite electrode exhibits high electrical conductivities of 1000 Scm−1 at 300 °C and 260 Scm−1 at 700 °C in an Ar atmosphere. The electrode exhibits excellent tolerance against grain growth during thermal cycling tests (R.T.↔800 °C), where the average growth rate of Mo grains in the Mo/TiN composite electrodes is controlled less than 0.5%/time (0.62→0.65 μm), while the growth rate in Mo electrodes is 306.7%/time (0.24→3.92 μm). It can be concluded that the Mo/TiN composite powder will suppress the degradation of the electrode and enhance the performance and durability of the unit cell at elevated temperatures. 相似文献