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Zhi-Qiang Wang,Zhi-Qiang Long,Xiao-Long Li 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.3
It is observed in test operation that for permanent magnet electro-magnetic suspension (PEMS) type high speed maglev train, when a single levitation unit in an end joint structure fails to work, the performance of the entire joint structure deteriorates rapidly, whereas in electro-magnetic suspension (EMS) type maglev system, there is no such phenomenon under the same failure. To solve this problem and to enhance system performance under faulty condition, fi rstly a comparative modeling of EMS and PEMS maglev end joint structure system was made to analyze the underlying reasons. Then a dynamic compensation method and a disturbance rejection method based on disturbance estimation and feedback linearization were proposed respectively. The performances of the proposed measures are verifi ed and compared in simulations.
Xiao-Qiang Li,Gui-Qiang Guo,Hong-Zhi Gao,Nan Song,Dong-Sheng Li 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.
Al-Cu-Mg aluminum alloy sheet is widely used for aircraft skin. Multi-stage forming combined with Solution Heat Treatment (SHT) is necessary for some geometrically complex productions in aircraft skin components. However, the effects of pre-strain and natural ageing time on the formability of Al-Cu-Mg aluminum alloy sheet are not fully understood. In this study, the deformation responses of an Al-Cu-Mg aluminum alloy sheet, over a range of pre-strain levels (0% to 6%) and natural ageing time levels (0 h to 2 h) were investigated. A modified Hollomon constitutive model coupling with pre-strain and natural ageing time was proposed to characterize the deformation responses of the Al-Cu-Mg aluminum alloy sheet. The hemispherical dome tests were performed at natural ageing time levels ranging from 0.25 h to 1.5 h. Marciniak and Kuczynski (M-K) theory was used to obtain the forming limit prediction model which takes pre-strain and natural ageing time into account. The theoretical Forming Limit Curves (FLCs) were compared with the experimental results.
MicroRNA-214-mediated UBC9 expression in glioma
( Zhi Qiang Zhao ),( Xiao Chao Tan ),( Ani Zhao ),( Li Yuan Zhu ),( Bin Yin ),( Jiang Ang Yuan ),( Bo Qin Qiang ),( Xiao Zhong Peng ) 생화학분자생물학회(구 한국생화학분자생물학회) 2012 BMB Reports Vol.45 No.11
It has been reported that ubiquitin-conjugating enzyme 9 (Ubc9), the unique enzyme2 in the sumoylation pathway, is up-regulated in many cancers. However, the expression and regulation of UBC9 in glioma remains unknown. In this study, we found that Ubc9 was up-regulated in glioma tissues and cell lines compared to a normal control. UBC9 knockdown by small interfering RNA (siRNA) affected cell proliferation and apoptosis in T98G cells. Further experiments revealed that microRNA (miR)-214 directly targeted the 3` untranslated region (UTR) of UBC9 and that there was an inverse relationship between the expression levels of miR-214 and UBC9 protein in glioma tissues and cells. MiR-214 overexpression suppressed the endogenous UBC9 protein and affected T98G cell proliferation. These findings suggest that miR-214 reduction facilitates UBC9 expression and is involved in the regulation of glioma cell proliferation.
The Size Dependence of Dissolution Thermodynamics of Nanoparticles
Zhi-Qiang Wang,Yongqiang Xue,Zixiang Cui,Huijuan Duan,Xiao-Yan Xia 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.9
Dissolution of nanoparticles is involved in the preparation, research and application of nanomaterials, but there is a surprising difference in dissolution thermodynamics between nanoparticles and the corresponding bulk materials. In the paper, the relations of dissolution thermodynamic properties, equilibrium constant of nanoparticles, respectively, and particle size were derived by introducing interface variables and the surface chemical potential. Experimentally, the solubility of nano-barium sulfate with different average particle sizes at different temperatures were determined by the method of electrical conductivity, obtaining the influencing regularities of particle size on the dissolution thermodynamic properties and the equilibrium constant. The regularities are in accordance with the theory. The results show that there are remarkable effects of particle size of nanoparticles on the dissolution thermodynamic properties and the equilibrium constant; with the decreasing of the size of nanoparticles, the dissolution equilibrium constant increases, while the standard dissolution Gibbs free energy, the standard dissolution enthalpy and the standard dissolution entropy decrease; and the logarithm of the dissolution equilibrium constant, the standard dissolution Gibbs free energy, the standard dissolution enthalpy and the standard dissolution entropy are linearly associated with the reciprocal of particle size, respectively. This new theory provides a quantitative description of nanoparticles dissolution behavior, and has important scientific significance for understanding and predicting of thermodynamic regularity of dissolution concerned in the preparation, researches and applications of nanomaterials.
Xiao-Ling Zheng,Zhi-Qiang Xiong,Jie-Qun Wu 한국식품과학회 2017 Food Science and Biotechnology Vol.26 No.1
Detection of the number of vegetative cells and endospores is necessary for quality control during the production of orally administered probiotic Bacillus licheniformis-containing tablets (BCT). However, there is no standard method for the rapid detection of vegetative cells and endospores in China. In this study, a simple flow cytometry (FCM) method was used to monitor the population dynamics of BCT. Using a specific fluorescent stain, SYBR green I, flow cytometric analysis could easily differentiate two morphological states of B. licheniformis. Compared with plate count assay (PCA) for determining the number of vegetative cells and endospores, the percentage of endospores determined by FCM was ~10% higher than that by PCA. Advantages of the FCM method over conventional methods include lower labor work, shorter detection time, and higher accuracy. Therefore, this simple FCM method could be a practical tool for monitoring quality control during the production of probiotic BCT
( Zhi-qiang Ren ),( Yan Liu ),( Xiao-qiong Pei ),( Zhong-liu Wu ) 한국미생물 · 생명공학회 2019 Journal of microbiology and biotechnology Vol.29 No.11
Ethyl (S)-3-hydroxy-3-(2-thienyl) propanoate ((S)-HEES) acts as a key chiral intermediate for the blockbuster antidepressant drug duloxetine, which can be achieved via the stereoselective bioreduction of ethyl 3-oxo-3-(2-thienyl) propanoate (KEES) that contains a 3-oxoacyl structure. The sequences of the short-chain dehydrogenase/reductases from Chryseobacterium sp. CA49 were analyzed, and the putative 3-oxoacyl-acyl-carrier-protein reductase, ChKRED12, was able to stereoselectively catalyze the NADPH-dependent reduction to produce (S)-HEES. The reductase activity of ChKRED12 towards other substrates with 3- oxoacyl structure were confirmed with excellent stereoselectivity (>99% enantiomeric excess) in most cases. When coupled with a cofactor recycling system using glucose dehydrogenase, the ChKRED12 was able to catalyze the complete conversion of 100 g/l KEES within 12 h, yielding the enantiopure product with >99% ee, showing a remarkable potential to produce (S)-HEES.
Xiao-qiang Ma,Er-zheng Su,Sen-wen Deng,Dong-zhi Wei 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.4
In this study, several chemical treatment techniques commonly used for protein extraction were investigated for recovering glutaryl-7-aminocephalosporanic acid acylase (GLA) from recombinant E. coli cells. The best results were obtained by the combined use of cetyltrimethylammonium bromide (CTAB) and KCl. Subsequently, various extraction conditions, such as cation salt, concentrations of CTAB and KCl, extraction temperature, extraction time, and biomass, were optimized to further enhance the release yield and specific activity of GLA. Our results showed that 110% of GLA was released after treatment with 0.5% CTAB (w/v, %) and 0.3 M KCl at 10°C for 12 h, and its specific activity in this extracting solution was approximately 1.5 times higher as compared to that obtained by sonication. This extraction method could avoid the inactivation of GLA caused by drastic mechanical methods, and also enhance its specific activity for industrial extraction.
Zhi-Qiang Feng,Xiao-Li Yang,Yuan-Feng Ye,Lin-Yun Hao 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.4
The design, synthesis, and structural characterization of two new palladium complexes based on Schiff base ligands is reported; [Pd(L1)2] (1) and [Pd(L2)2] (2), [HL1 = 2-((E)-(2,6-diethylphenylimino)methyl)-4,6- dibromophenol, L2 = (E)-N-benzylidene-2,6-diethylbenzenamine], which are obtained by functionalizing Schiff base ligands with or without electron-withdrawing groups. Both compounds are mononuclear structures. Comparisons are made to the compounds 1 and 2 to analyze and understand the effect of electron-withdrawing groups. Antibacterial activity studies indicate the electron-withdrawing groups on Schiff base ligands enhance antibacterial activity. Catalytic activity, however, is reduced due to the enhanced steric-hindrance of the electron-withdrawing groups. Electronic absorption and emission properties of HL1, L2, 1 and 2 are also reported.
You, Zhi-Mei,Zhao, Liang,Xia, Jing,Wei, Qiang,Liu, Yu-Min,Liu, Xiao-Yan,Chen, Di-Long,Li, Jing Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.3
Aims and Background: Ginsenoside Rh2, which exerts the potent anticancer action both in vitro and in vivo, is one of the most well characterized ginsenosides extracted from ginseng. Although its effects on cancer are significant, the underlying mechanisms remain unknown. In this study, we sought to elucidate possible links between ginsenoside Rh2 and phosphoglucose isomerase/autocrine motility factor (PGI/AMF). Methods: $KG1{\alpha}$, a leukemia cell line highly expressing PGI/AMF was assessed by western blot analysis and reverse transcription- PCR (RT-PCR) assay after transfection of a small interfering (si)-RNA to silence PGI/AMF. The effect of PGI/AMF on proliferation was measured by typan blue assay and antibody array. A cell counting kit (CCK)-8 and flow cytometry (FCM) were adopted to investigate the effects of Rh2 on PGI/AMF. The relationships between PGI/AMF and Rh2 associated with Akt, mTOR, Raptor, Rag were detected by western blot analysis. Results: KG1${\alpha}$ cells expressed PGI/AMF and its down-regulation significantly inhibited proliferation. The antibody array indicated that the probable mechanism was reduced expression of PARP, State1, SAPK/JNK and Erk1/2, while those of PRAS40 and p38 were up-regulated. Silencing of PGI/AMF enhanced the sensibility of $KG1{\alpha}$ to Rh2 by suppressing the expression of mTOR, Raptor and Akt. Conclusion: These results suggested that ginsenoside Rh2 suppressed the proliferation of $KG1{\alpha}$, the same as down-regulation of PGI/AMF. Down-regulation of PGI/AMF enhanced the pharmacological effects of ginsenoside Rh2 on KG1${\alpha}$ by reducing Akt/mTOR signaling.