Financial Systems and Economic Outcomes: A Comparative Perspective

Shang-Jin Wei 연세대학교 동서문제연구원 2014 Global economic review Vol.43 No.4

Offshore Investment Funds

Shang-Jin Wei,Woochan Kim 대외경제정책연구원 1999 East Asian Economic Review Vol.3 No.4

Offshore investment funds are alleged to have engaged in trading behavior that is different from their onshore counterparts because they may be subject to less supervision and regulation. In particular, they may trade more intensely. They could also pursue more aggressively certain trading strategies such as positive feedback trading or herding that could contribute to a greater volatility in the market. Using a unique data set, this chapter compares the trading behavior in the Korean stock market between offshore investment funds with their onshore counterparts registered in the US and UK. There are a number of interesting findings. First, there is indeed evidence suggesting that the offshore funds trade more intensely than their onshore counterparts. Second, however, there is no evidence that the offshore funds engage in positive feedback trading. In contrast, there is strong evidence that the funds from the U.S. and U.K. do. Third, while offshore funds do herd, they do so far less than onshore funds in the U.S. or UK. Fourth, offshore funds hold less glamour stocks (e.g. stocks with high P/E) in their portfolio than funds in the U.S. or U.K. do. Moreover, flight to glamour stocks during the in-crisis period is less evident in the case of offshore funds. In sum, offshore funds are no especially worrisome monsters.

Anti-HIV-1 Activity of Lignans from the Fruits of Schisandra rubriflora

Wei-Lie Xiao,Rui-Rui Wang,Wei Zhao,Ren-Rong Tian,Shan-Zhai Shang,Liu-Meng Yang,Jian-Hong Yang,Jian-Xin Pu,Yong-Tang Zheng,Han-Dong Sun 대한약학회 2010 Archives of Pharmacal Research Vol.33 No.5

This study investigated the 70% aqueous acetone extract of the fruits of Schisandra rubriflora which led to the isolation of eight lignans, including a new isolate, rubrisandrin C (1), and seven known lignans (2-8) . The structure of 1 was established by extensive 1D and 2D NMR spectroscopy and its absolute stereochemistry was determined by CD spectrum. Compounds 1-5 and 7-8 were evaluated for their anti-HIV-1 activity that showed inhibitory activity on HIV-1IIIB induced syncytium formation with EC50 values in the range of 2.26~20.4 μg/mL. Compounds 1 and 7 exerted their obvious protection of HIV-1IIIB inducted MT-4 host cells lytic effects with a selectivity index of 15.4 and 24.6, respectively.

Determine the robot assistive forces based on human intent estimation in bone cutting applications

Shang-Wei Hsu,Ping-Lang Yen 제어로봇시스템학회 2013 제어로봇시스템학회 국제학술대회 논문집 Vol.2013 No.10

Robots can provide real-time bone cutting assistance on various operational conditions. A human intent estimation together with a bilateral force control has been designed to assist the surgeon in total knee replacement. Different admittance gains are online adjusted based on estimated human intent, followed by the robot to exert appropriate forces to the cutter, either pushing or pulling forces so that the bone cutting can be carried out in easier, safer and more precise way. Experiments show that the proposed control structure is promising to meet the clinical needs for real-time bone cutting assistance.

Genetic diversity and spread of Lissorhoptrus oryzophilus (Coleoptera: Curculionidae) in China, based on amplified fragment length polymorphism

Shang-Wei Li,Fang-Chao Wei,Juan Du,Mao-Fa Yang 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.3

The rice water weevil (RWW), Lissorhoptrus oryzophilus Kuschel, is one of the most destructive pests causing heavy rice yield loss worldwide. In the present study, amplified fragment length polymorphism (AFLP) was used to analyze the genetic differentiation and transmission routes of 26 RWW geographical populations from Guizhou and 6 other provinces in China. The genetic distance between the 26 populations ranged from 0 to 0.693; the genetic distance between Guizhou and 6 other provinces populations varied from 0.043 to 0.693, with an average of 0.382. There was higher genetic variation among the populations from Guizhou and 6 other provinces compared with populations within Guizhou. The Mantel test showed no correlation between the genetic and geographical distances of the 26 populations. According to genetic distance, clustering, and time that RWW was found in these regions, we deduced that the pest entered Guizhou and spread in this province most likely via three routes: (1) from Hebei to Zunyi and southward to the south-central regions; (2) from Sichuan to Bijie and eastward to the central regions; and (3) from Yunnan through Anshun to the central regions and Qiandongnan prefecture. RWW spread in a natural manner, including flight, crawling, swimming, and by human-associated mechanisms, comprising dissemination through paddies and hay and hitchhiking on human transportations.

Numerical investigation of the critical heat fl ux in a 5 × 5 rod bundle with multi-grid

Wei Liu,Zemin Shang,Shihao Yang,Lixin Yang,Zihao Tian,Yu Liu,Xi Chen,Qian Peng 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.5

To improve the heat transfer efficiency of the reactor fuel assembly, it is necessary to accurately calculatethe two-phase flow boiling characteristics and the critical heat flux (CHF) in the fuel assembly. In thispaper, a Eulerian two-fluid model combined with the extended wall boiling model was used tonumerically simulate the 5 5 fuel rod bundle with spacer grids (four sets of mixing vane grids and foursets of simple support grids without mixing vanes). We calculated and analyzed 11 experimental conditions under different pressure, inlet temperature, and mass flux. After comparing the CHF and thelocation of departure from the nucleate boiling obtained by the numerical simulation with the experimental results, we confirmed the reliability of computational fluid dynamic analysis for the prediction ofthe CHF of the rod bundle and the boiling characteristics of the two-phase flow. Subsequently, weanalyzed the influence of the spacer grid and mixing vanes on the void fraction, liquid temperature, andsecondary flow distribution. The research in this article provides theoretical support for the design of fuelassemblies

Systems-level Modeling with Molecular Resolution Elucidates the Rate-limiting Mechanisms of Cellulose Decomposition by Cellobiohydrolases

Shang, Barry Z.,Chang, Rakwoo,Chu, Jhih-Wei American Society for Biochemistry and Molecular Bi 2013 The Journal of biological chemistry Vol.288 No.40

<P>Interprotein and enzyme-substrate couplings in interfacial biocatalysis induce spatial correlations beyond the capabilities of classical mass-action principles in modeling reaction kinetics. To understand the impact of spatial constraints on enzyme kinetics, we developed a computational scheme to simulate the reaction network of enzymes with the structures of individual proteins and substrate molecules explicitly resolved in the three-dimensional space. This methodology was applied to elucidate the rate-limiting mechanisms of crystalline cellulose decomposition by cellobiohydrolases. We illustrate that the primary bottlenecks are slow complexation of glucan chains into the enzyme active site and excessive enzyme jamming along the crowded substrate. Jamming could be alleviated by increasing the decomplexation rate constant but at the expense of reduced processivity. We demonstrate that enhancing the apparent reaction rate required a subtle balance between accelerating the complexation driving force and simultaneously avoiding enzyme jamming. Via a spatiotemporal systems analysis, we developed a unified mechanistic framework that delineates the experimental conditions under which different sets of rate-limiting behaviors emerge. We found that optimization of the complexation-exchange kinetics is critical for overcoming the barriers imposed by interfacial confinement and accelerating the apparent rate of enzymatic cellulose decomposition.</P>

Gradual electroforming and memristive switching in Pt/CuO_<i>x</i>/Si/Pt systems

Wei, L L,Shang, D S,Sun, J R,Lee, S B,Sun, Z G,Shen, B G IOP Pub 2013 Nanotechnology Vol.24 No.32

<P>We report a memristive switching effect in Pt/CuO<SUB><I>x</I></SUB>/Si/Pt devices prepared by the rf sputtering technique at room temperature. Differently from other Cu-based metal filament switching systems, a gradual electroforming process, marked by a gradual increase of the device resistance and a gradual decrease of the device capacitance, was observed in the current–voltage and capacitance characteristics. After the gradual electroforming, the devices show a uniform memristive switching behavior. By Auger electron spectroscopy analysis, a model based on the thickness change of the SiO<SUB><I>x</I></SUB> layer at the CuO<SUB><I>x</I></SUB>/Si interface and Cu ion migration is proposed for the gradual electroforming and uniform memristive switching, respectively. This work should be meaningful for the preparation of forming-free and homogeneous memristive devices.</P>

Estimation of shallow groundwater ages and circulation rates in the Henan Plain, China: CFC and deuterium excess methods

Wei-hong Dong,Bo Kang,Shang-hai Du,Xu-fei Shi 한국지질과학협의회 2013 Geosciences Journal Vol.17 No.4

CFC age and deuterium excess methods were applied to the estimation of groundwater circulation rates in the Quaternary shallow groundwater system of the Henan Plain. The results provide a basis for groundwater renewability evaluation. The spatial distribution of CFC age shows that the groundwater system mainly comprises modern water, less than 50 a. The groundwater of less than 30 a was in the piedmont zone of the Taihang, Funiu, and Dabie Mountains, indicating short groundwater residence times,and fast groundwater cycling, with circulation rates of 27–31 m/d. Groundwater cycling along the Yellow River was also rapid because of exchange with the Yellow River. The circulation rates were 34–54m/d. In the areas around Tongxu, Shangqiu, Taikang, Xiangcheng,in the middle of the study area, and east of Huaxian-Changyuan and Xixian, Gushi in the south, groundwater age was 30–40 a, suggesting a longer groundwater residence time. The groundwater cycle in these areas was slower than in the piedmonts, and the area along the Yellow River. The circulation rates were 15–26 m/d. In the areas of Luyi, Yongcheng, Zhumadian, Xincai and Huaibin,the groundwater age was older than 40 a, with the longest residence times and slowest circulation rates (~12 m/d). The correlation between groundwater age and deuterium excess averages for the northern, central, southern shallow groundwater systems and the <30 a, 30–40 a, >40 a groundwater age divisions was strong (R = 0.9714), showing that the groundwater residence time embodied by the deuterium excess parameter was consistent with groundwater age estimated using the CFC method.

Structural and functional analyses of the lipase CinB from <i>Enterobacter asburiae</i>

Shang, Fei,Lan, Jing,Liu, Wei,Chen, Yuanyuan,Wang, Lulu,Zhao, Jing,Chen, Jinli,Gao, Peng,Ha, Nam-Chul,Quan, Chunshan,Nam, Ki Hyun,Xu, Yongbin Elsevier 2019 Biochemical and biophysical research communication Vol.519 No.2

<P><B>Abstract</B></P> <P>Lipases are widely present in various plants, animals and microorganisms, constituting a large category of enzymes. They have the ability to catalyze the cleavage of ester bonds. The lipase CinB from <I>Enterobacter asburiae</I> (<I>E. asburiae</I>) is an acetyl esterase. The primary amino acid sequence suggests that the EaCinB protein belongs to the α/β-hydrolase (ABH) superfamily of the esterase/lipase superfamily. However, its molecular functions have not yet been determined. Here, we report the crystal structure of <I>E. asburiae</I> CinB at a 1.45 Å resolution. EaCinB contains a signal peptide, cap domain and catalytic domain. The active site of EaCinB contains the catalytic triad (Ser180-His307-Asp277) on the catalytic domain. The oxyanion hole is composed of Gly106 and Gly107 within the conserved sequence motif HGGG (amino acid residues 106–109). The substrate is accessible between the α1 and α2 helices or the α1 helix and catalytic domain. Narrow substrate pockets are formed by the α2 helix of the cap domain. Site-directed mutagenesis showed that EaCinB-W208H exhibits a higher catalytic ability than EaCinB-WT by approximately nine times. Our results provide insight into the molecular function of EaCinB.</P> <P><B>Highlights</B></P> <P> <UL> <LI> EaCinB structure contains a signal peptide, cap domain and catalytic domain. </LI> <LI> The active site of EaCinB contains the catalytic triad (Ser180-His307-Asp277). </LI> <LI> The oxyanion hole is composed of Gly106 and Gly107. </LI> <LI> Substrate-binding mode of EaCinB are proposed. </LI> <LI> Site-directed mutagenesis showed that EaCinB-W208H exhibits a higher catalytic ability than EaCinB-WT. </LI> </UL> </P>