• Title/Summary/Keyword: Li Gao

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Hepatitis C Virus Non-structural Protein NS4B Can Modulate an Unfolded Protein Response

  • Zheng Yi;Gao Bo;Ye Li;Kong Lingbao;Jing Wei;Yang Xiaojun;Wu Zhenghui;Ye Linbai
    • Journal of Microbiology
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    • v.43 no.6
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    • pp.529-536
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    • 2005
  • Viral infection causes stress to the endoplasmic reticulum (ER). The response to endoplasmic reticulum stress, known as the unfolded protein response (UPR), is designed to eliminate misfolded proteins and allow the cell to recover. The role of hepatitis C virus (HCV) non-structural protein NS4B, a component of the HCV replicons that induce UPR, is incompletely understood. We demonstrate that HCV NS4B could induce activating transcription factor (ATF6) and inositol-requiring enzyme 1 (IRE1), to favor the HCV subreplicon and HCV viral replication. HCV NS4B activated the IRE1 pathway, as indicated by splicing of X box-binding protein (Xbp-1) mRNA. However, transcriptional activation of the XBP-1 target gene, EDEM (ER degradation-enhancing $\alpha-mannosidase-like$ protein, a protein degradation factor), was inhibited. These results imply that NS4B might induce UPR through ATF6 and IRE1-XBP1 pathways, but might also modify the outcome to benefit HCV or HCV subreplicon replication.

High Ratio Bidirectional DC-DC Converter with a Synchronous Rectification H-Bridge for Hybrid Energy Sources Electric Vehicles

  • Zhang, Yun;Gao, Yongping;Li, Jing;Sumner, Mark;Wang, Ping;Zhou, Lei
    • Journal of Power Electronics
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    • v.16 no.6
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    • pp.2035-2044
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    • 2016
  • In order to match the voltages between high voltage battery stacks and low voltage super-capacitors with a high conversion efficiency in hybrid energy sources electric vehicles (HESEVs), a high ratio bidirectional DC-DC converter with a synchronous rectification H-Bridge is proposed in this paper. The principles of high ratio step-down and step-up operations are analyzed. In terms of the bidirectional characteristic of the H-Bridge, the bidirectional synchronous rectification (SR) operation is presented without any extra hardware. Then the SR power switches can achieve zero voltage switching (ZVS) turn-on and turn-off during dead time, and the power conversion efficiency is improved compared to that of the diode rectification (DR) operation, as well as the utilization of power switches. Experimental results show that the proposed converter can operate bidirectionally in the wide ratio range of 3~10, when the low voltage continuously varies between 15V and 50V. The maximum efficiencies are 94.1% in the Buck mode, and 93.6% in the Boost mode. In addition, the corresponding largest efficiency variations between SR and DR operations are 4.8% and 3.4%. This converter is suitable for use as a power interface between the battery stacks and super-capacitors in HESEVs.

Kinetics of Horseradish Peroxidase-Catalyzed Nitration of Phenol in a Biphasic System

  • Kong, Mingming;Zhang, Yang;Li, Qida;Dong, Runan;Gao, Haijun
    • Journal of Microbiology and Biotechnology
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    • v.27 no.2
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    • pp.297-305
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    • 2017
  • The use of peroxidase in the nitration of phenols is gaining interest as compared with traditional chemical reactions. We investigated the kinetic characteristics of phenol nitration catalyzed by horseradish peroxidase (HRP) in an aqueous-organic biphasic system using n-butanol as the organic solvent and ${NO_2}^-$ and $H_2O_2$ as substrates. The reaction rate was mainly controlled by the reaction kinetics in the aqueous phase when appropriate agitation was used to enhance mass transfer in the biphasic system. The initial velocity of the reaction increased with increasing HRP concentration. Additionally, an increase in the substrate concentrations of phenol (0-2 mM in organic phase) or $H_2O_2$ (0-0.1 mM in aqueous phase) enhanced the nitration efficiency catalyzed by HRP. In contrast, high concentrations of organic solvent decreased the kinetic parameter $V_{max}/K_m$. No inhibition of enzyme activity was observed when the concentrations of phenol and $H_2O_2$ were at or below 10 mM and 0.1 mM, respectively. On the basis of the peroxidase catalytic mechanism, a double-substrate ping-pong kinetic model was established. The kinetic parameters were ${K_m}^{H_2O_2}=1.09mM$, ${K_m}^{PhOH}=9.45mM$, and $V_{max}=0.196mM/min$. The proposed model was well fit to the data obtained from additional independent experiments under the suggested optimal synthesis conditions. The kinetic model developed in this paper lays a foundation for further comprehensive study of enzymatic nitration kinetics.

A New Method to Estimate the Magnetic Field Modulation Effect of Brushless Doubly-Fed Machine with Cage Rotor

  • Liu, Hanghang;Han, Li;Gao, Qiang
    • Journal of international Conference on Electrical Machines and Systems
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    • v.1 no.3
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    • pp.330-335
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    • 2012
  • Brushless doubly-fed machine (BDFM) doesn't use brush and slip ring, and has advantages such as high system reliability, small capacity of its frequency converter, low system cost, adjustable power factor and speed, etc. At the same time, it has good applicable potentials on the variable frequency motors and the variable speed constant frequency generators. However, due to the complicacy and particularity of BDFM in the structure and operating mechanism, the effect of magnetic field modulation directly influences the operating efficiency of BDFM. To study the effect of different cage rotor structures on the magnetic field modulation of BDFM, the rotor magnetomotive force (MMF) of BDFM with cage rotor is studied by the analytical method. The components and features of rotor harmonic MMFs are discussed. At the same time, the method to weaken the higher harmonics is analyzed by the theoretic formulae. Furthermore, the magnetic field modulation mechanism is expounded on in detail and the relationship between the magnetic field modulation effect and the operating efficiency of BDFM is established. And then, a new method for estimating the magnetic field modulation effect is proposed. At last, the magnetic field modulation effects of four BDFM prototypes with different cage rotor structures are compared by the MMF analysis and the efficiency data of electromagnetic design. The results verify the effectiveness of the new method for estimating the magnetic field modulation effect of BDFM with cage rotor.

The Study on Common Cold recorded in Chinese Medical Journal (중의잡지(中醫雜誌)에 보고(報告)된 감모(感冒)에 대(對)한 고찰(考察))

  • Lim, Do-Hee;Bae, Han-Ho;Park, Yang-Chun
    • Journal of Haehwa Medicine
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    • v.13 no.2
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    • pp.231-249
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    • 2004
  • This study analyzed the contents of the research papers concerning the common cold recorded in Chinese medical journal published over the period between 2000 and 2004. As a result, the following conclusion was drawn. 1. Among the clinical research papers, There are a lot of treatment papers of traditional chinese medicine in the method of treatment. There are a lot of papers about Feng-Re-Xing(風熱型) and Xu-Zheng-Xing(虛證型) in the Bian-Zheng-Lei-Xing(辨證類型) 2. "Zhong-Yi-Xu-Zheng-Bian-Zheng-Can-Kao-Biao-Zhun" ("中醫虛證辨證參考標準"), "Zhong-Yi-Nei-Ke-Wu-Ban-Jiao-Cai"("中醫內科五版敎材"), "Zhong-Hua-Ren-Min-Gong-He-Guo-Zhong-Yi-Yao-Hang-Ye-Biao-Zhun"("中華人民共和國醫藥行業標準"), "Gan-Mao-Zhen-Duan-Biao-Zhun"("感冒診斷漂準"), "Zhong-Yi-Bing-Zheng-Zhen-Duan-Liao-Xiao-Biao-Zhun"("中醫病證診斷療效標準"), "Quan-Guo-Gao-Deng-Yi-Xue-Yuan-Xiao-Zhong-Yi-Zhuan-Ye-Jiao-Cai"("全國高等醫藥院校中醫專業敎材") are used as the criterion for diagnosis in Chinese medicine. 3. It is mainly used "Zhong-Yi-Bing-Zheng-Zhen-Duan-Liao-Xiao-Biao-Zhun"("中醫病證診斷療效標準") as the criterion for treatment effect evaluation, and symptom of traditional chinese medicine, the frequency and the duration of common cold, measurement of immunologic function are used as assistant evaluation indicator. 4. The research papers reported that the use of prescriptions such as Chai-Qi-Fang-Jiao-Tang, Tui-Re-He-Ji(退熱合劑), Ti-Xu-Gan-Mao-He-Ji(體虛感冒合劑), Yu-Ping-Feng-San-He-Gui-Zhi-Tang(玉屛風散合桂枝湯), Chai-Guan-Jie-Re-Ke-Li(柴貫解熱顆粒), Hu-Qin-He-Ji(蒿芩合劑), Lian-Hua-Feng-Cha(蓮花峰茶), Kang-Gan-He-Ji(抗感合劑), Bing-Du-He-Ji(病毒合劑), Zhong-Gan-Ling-Pian(重感靈片) led to the high efficacy 5. The pharmacological research papers reported that Yu-Ping-Feng-San(玉屛風散) have influence on IgA, phagocytic function of macrophage, the total number of splenocyte and PEC.

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Synthesis, Crystal Structure and Quantum Chemistry of a Novel Schiff Base N-(2,4-Dinitro-phenyl)-N'-(1-phenyl-ethylidene)-hydrazine

  • Ji, Ning-Ning;Shi, Zhi-Qiang;Zhao, Ren-Gao;Zheng, Ze-Bao;Li, Zhi-Feng
    • Bulletin of the Korean Chemical Society
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    • v.31 no.4
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    • pp.881-886
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    • 2010
  • A novel Schiff base N-(2,4-dinitro-phenyl)-N'-(1-phenyl-ethylidene)-hydrazine has been synthesized and structurally characterized by X-ray single crystal diffraction, elemental analysis, IR spectra and UV-vis spectrum. The crystal belongs to monoclinic with space group P21/n. The molecules are connected via intermolecular O-$H{\cdots}O$ hydrogen bonds into 1D infinite chains. The crystal structure is consolidated by the intramolecular N-$H{\cdots}O$ hydrogen bonds. weak intermolecular C-$H{\cdots}O$ hydrogen bonds link the molecules into intriguing 3D framework. Furthermore, Density functional theory (DFT) calculations of the structure, stabilities, orbital energies, composition characteristics of some frontier molecular orbitals and Mulliken charge distributions of the title compound were performed by means of Gaussian 03W package and taking B3LYP/6-31G(d) basis set. The time-dependent DFT calculations have been employed to calculate the electronic spectrum of the title compound, and the UV-vis spectra has been discussed on this basis. The results show that DFT method at B3LYP/6-31G(d) level can well reproduce the structure of the title compound.

Dynamic Studies on Physiology and Biochemistry in American Seng Seed During Stratification - Part I. Embryo Ratio, Dry Weight Ratio and respiration Rate (충적과정 중 미국삼 종자의 생리 및 생화학적 지표에 관한 동태학적 연구 I. 배아율, 건조중량비 및 호흡강도)

  • Huang, Yao-Ge;Li, Xiang-Gao;Yang, Ji-Xiang;Kuang, Ya-Lan;Yan, Jie-Kun;Cui, Shu-Yu;Liu, Ren-Song;Kim, Hack-Seang
    • Journal of Ginseng Research
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    • v.20 no.3
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    • pp.325-330
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    • 1996
  • Dynamic parameters of physiology including embryo ratio (ER), embryo length to endosperm length, dry weight ratio between embryo and endosperm (DWR) and respiration rate (RR) in American send (Panax quinquefolium L.) seed were investigated. According to the changes of ER during seed stratification, the duration of embryo afterripening could be divided into three stages as \circled1 embryo slow growth stage (ESGS), ER increased from 7.31% to 20.48% (0.16% day-1): \circled2 embryo rapid growth stage (ERGS), ER increased to 80.98% (0.61% day-1) (75G5+ ERGS=morphological afterripening stage (MP,5)) and \circled3pysiological afterripening stage (PAS), ER Increased to 88.50% (0.094 day-1) only. DWR Increased slowly from 0.20% to 2.76clp (0.016% day-1) in MAS and rapidly to 8.81% (0.061% day-1) in PAS. The RR correlated significantly with ER as well (r=0.8934 > rot, 0.6610). The steep increment of both DWR and RR in PAS indicated that the PAS was not a static stage although the ER was not changed too much. All of these may provide some information for understanding the dormancy mechanisms of American sting seed.

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Remarkable impact of steam temperature on ginsenosides transformation from fresh ginseng to red ginseng

  • Xu, Xin-Fang;Gao, Yan;Xu, Shu-Ya;Liu, Huan;Xue, Xue;Zhang, Ying;Zhang, Hui;Liu, Meng-Nan;Xiong, Hui;Lin, Rui-Chao;Li, Xiang-Ri
    • Journal of Ginseng Research
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    • v.42 no.3
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    • pp.277-287
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    • 2018
  • Background: Temperature is an essential condition in red ginseng processing. The pharmacological activities of red ginseng under different steam temperatures are significantly different. Methods: In this study, an ultrahigh-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry was developed to distinguish the red ginseng products that were steamed at high and low temperatures. Multivariate statistical analyses such as principal component analysis and supervised orthogonal partial least squared discrimination analysis were used to determine the influential components of the different samples. Results: The results showed that different steamed red ginseng samples can be identified, and the characteristic components were 20-gluco-ginsenoside Rf, ginsenoside Re, ginsenoside Rg1, and malonyl-ginsenoside Rb1 in red ginseng steamed at low temperature. Meanwhile, the characteristic components in red ginseng steamed at high temperature were 20R-ginsenoside Rs3 and ginsenoside Rs4. Polar ginsenosides were abundant in red ginseng steamed at low temperature, whereas higher levels of less polar ginsenosides were detected in red ginseng steamed at high temperature. Conclusion: This study makes the first time that differences between red ginseng steamed under different temperatures and their ginsenosides transformation have been observed systematically at the chemistry level. The results suggested that the identified chemical markers can be used to illustrate the transformation of ginsenosides in red ginseng processing.

Study on Thermodynamics of Three Kinds of Benzindocarbocyanine Dyes in Aqueous Methanol Solution

  • Huang, Wei;Wang, Lan-Ying;Fu, Yi-Le;Liu, Ji-Quan;Tao, You-Ni;Fan, Fang-Li;Zhai, Gao-Hong;Wen, Zhen-Yi
    • Bulletin of the Korean Chemical Society
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    • v.30 no.3
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    • pp.556-560
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    • 2009
  • Aggregation behavior of three kinds of benzindocarbocyanine dyes in aqueous methanol solution was studied by UV-Vis absorption spectrum. The results indicated that the three dyes all existed monomer-dimer equilibrium in aqueous methanol solution (concentration range $10^{−5}\;to\;10^{−6}$ M) at 25.0$\sim$41.0 ${^{\circ}C}$ for Dye 1, 28.0$\sim$49.0 ${^{\circ}C}$ for Dye 2 and 26.0$\sim$47.0 ${^{\circ}C}$ for Dye 3. The fundamental property of the three dyes as the dimeric association constant KD, the dimeric free energy ${\Delta$}G_D, the dimeric entropy ${\Delta$}S_D, and the dimeric enthalpy ${\Delta$}H_D were determined. The ${\Delta$}H_D of three dyes: Dye 1, Dye 2 and Dye 3 was -42.5, -15.1 and -18.9 kJ/mol, respectively. The experimental observations were the subject of a theoretical study including the ground-state geometries which were fully optimized using DFT at B3LYP/6-31G level. The effect of dye molecule structure on ${\Delta$}H_D was discussed by theoretical calculations.

Dynamic Studies on Physiology and Biochemistry in American Ginseng Seed During Stratification Part III. POD Activity, Contents of DNA and RNA, Isozymes of POD and ES - (충적과정중 미국인삼 종자의 생리 및 생화하적 지표에 관한 동태학적 연구 III)

  • Huang, Yao-Ge;Li, Xiang-Gao;Kuang, Ya-Lan;Yan, Jie-Kun;Cui, Shu-Yu;Yu, Wen-Bo;Yang, Ji-Xiang;Liu, Ren-Song;Kim, Hack-Seang
    • Journal of Ginseng Research
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    • v.21 no.1
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    • pp.43-48
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    • 1997
  • Dynamic parameters of biochemistry including the POD (peroxidase) activity, contents of DNA and RNA, isozymes of POD and ES (esterase) in American send (Panax quinquefolium L.) seed are reported in the present paper. The dynamic changes of POD activity proved that the PAS (physiological afterripening stage) is a stage in which some substances are prepared for seed germination. The POD activity correlated with ER (embryo ratio) significantly DNA content changed little only within 0.0036∼0.013 mg/ml, which did not correlate with ER. RNA content changed from 0.1539 to 1.0313 mg/ml and correlated significantly with RE during all of the embryo afterripening. None of the POD isozyme band was obtained in ESGS (embryo slowly growth stage), but five bands in ERGS (embryo rapidly growth stage) and six bands in PAS. Four bands of ES isozymes were obtained in ESGS, but six bands in ERGS, particularly, the content of ES isozymes increased in PAS. All of these may provide some information for understanding the dormancy mechanisms of American song seed.

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