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| 1 | Engineering Escherichia coli to improve tryptophan production via genetic manipulation of precursor and cofactor pathways显示文摘Optimizing the supply of biosynthetic precursors and cofactors is usually an effective metabolic strategy to improve the production of target compounds.Here,the combination of optimizing precursor synthesis and balancing cofactor metabolism was adopted to improve tryptophan production in Escherichia coli.First,glutamine synthesis was improved by expressing heterologous glutamine synthetase from Bacillus subtilis and Bacillus megaterium in the engineered Escherichia coli strain KW001,resulting in the best candidate strain TS-1.Then icd and gdhA were overexpressed in TS-1,which led to the accumulation of 1.060 g/L tryptophan.Subsequently,one more copy of prs was introduced on the chromosome to increase the flux of 5-phospho-α-D-ribose 1-diphosphate followed by the expression of mutated serA and thrA to increase the precursor supply of serine,resulting in the accumulation of 1.380 g/L tryptophan.Finally,to maintain cofactor balance,sthA and pntAB,encoding transhydrogenase,were overexpressed.With sufficient amounts of precursors and balanced cofactors,the engineered strain could produce 1.710 g/L tryptophan after 48 h of shake-flask fermentation,which was 2.76-times higher than the titer of the parent strain.Taken together,our results demonstrate that the combination of optimizing precursor supply and regulating cofactor metabolism is an effective approach for high-level production of tryptophan.Similar strategies could be applied to the production of other amino acids or related derivatives. | Zhu Li Dongqin Ding Huiying Wang Linxia Liu Huan Fang Tao Chen Dawei Zhang | 2020 | Synthetic and Systems Biotechnology2020，5，3： | 5 |
| 2 | Study on growing thick AlGaN layer on c-plane sapphire substrate and free-standing GaN substrate显示文摘In this study,the thick AlGaN epilayers have been grown on the c-plane sapphire substrate and the free-standing GaN substrate using low-temperature AlN nucleation layers by low-pressure metal-organic chemical vapor deposition(LPMOCVD).High resolution X-ray diffraction(HRXRD),atom force microscopy(AFM),scanning electron microscopy(SEM),photoluminescence(PL) and Raman scattering measurements have been employed to study the crystal quality,threading dislocation density,surface morphology,optical properties and phonon properties of thick AlGaN epifilms.The results indicate that AlGaN epifilms crystal quality can be improved greatly when grown on the free-standing GaN substrate.We calculated the threading dislocation density and found that thick AlGaN epifilm grown on the free-standing GaN substrate is much lower in total threading dislocation density than that grown on the sapphire substrate,although the surface morphology is rougher than that of sapphire substrate. | WANG DangHui ZHOU Hao ZHANG JinCheng XU ShengRui ZHANG LinXia MENG FanNa AI Shan HAO Yue | 2012 | Science China(Physics,Mechanics & Astronomy)2012，55，12： | 3 |
| 3 | Heavy ion micro-beam study of single-event transient(SET) in Si Ge heterjunction bipolar transistor显示文摘Silicon-germainum heterojunction bipolar transistor(Si Ge HBT)has been demonstrated to be suitable in extreme environment because of its superior temperature characteristics which can operate from 43 K to 400 K[1].In addition,outstanding hardness to both total ionizing dose(TID)radiation and displacement damage make Si Ge HBT technology particularly attractive for | Jinxin ZHANG Hongxia GUO Fengqi ZHANG Chaohui HE Pei LI Yunyi YAN Hui WANG Linxia ZHANG | 2017 | Science China(Information Sciences)2017，60，12： | 2 |
| 4 | Preparation of lead carbonate from spent lead paste via chemical conversion显示文摘 | Xinfeng Zhu Jiakuan Yang Linxia Gao Jianwen Liu Danni Yang Xiaojuan Sun Wei Zhang Qin Wang Lei Li Dongsheng He R. Vasant Kumar | 2013 | Hydrometallurgy2013，，： | 1 |
| 5 | Gasifi- cation reactivity and kinetics of typical Chinese anthra- cite chars with steam and CO2显示文摘 | Zhang Linxia Huang Jiejie Fang Yitian | 2006 | Energy Fuels2006，20，3： | 1 |
| 6 | Intensive atorvastatin therapy attenuates the inflammatory responses in monocytes of patients with unstable angina undergoing pereutaneous coronary intervention via peroxisome prolifemtor- activated receptor γactivation显示文摘 | Jing Yang Changqing Liu Linxia Zhang | 2015 | Inflammation2015，38，4： | 1 |
| 7 | Leaching of spent lead acid battery paste components by sodium citrate and acetic acid显示文摘 | Xinfeng Zhu Xiong He Jiakuan Yang Linxia Gao Jianwen Liu Danni Yang Xiaojuan Sun Wei Zhang Qin Wang R Vasant Kumar | 2013 | Journal of Hazardous Materials2013，，： | 1 |
| 8 | Leaching of spent lead acid battery paste components by sodium citrate and acetic acid显示文摘 | Xinfeng Zhu Xiong He Jiakuan Yang Linxia Gao Jianwen Liu Danni Yang Xiaojuan Sun Wei Zhang Qin Wang R Vasant Kumar | 2013 | Journal of Hazardous Materials2013，，： | 1 |
| 9 | Polyvinylpyrrolidone as an Efficient Stabilizer for Silver Nanoparticles显示文摘Aggregation of nanoparticles is a serious problem in their applications.In this article,stability of biosynthesized silver nanoparticles(AgNPs)was initially studied with different concentrations of sodium chloride(NaCl).Surfactant screening showed that polyvinylpyrrolidone(PVP)was an ideal stabilizer,which not only was effective at a low concentration(0.1%,V/V),but also could protect silver colloids from aggregation for a long period at 1 mol•L^(−1) NaCl,and 6 h even at 3 mol•L^(−1) NaCl.However,some other surfactants,such as sodium dodecyl(SDS),Triton X-100,Tween-20,and Tween-80,could not prevent AgNPs from aggregation even at a high concentration up to 0.5%(V/V).This AgNPs stabilizer is simple and convenient for a variety of applications compared with others. | Weidong Huang Linxia Zhang Qiuping Yang Zhimin Wang | 2014 | Chinese Journal of Chemistry2014，32，9： | 0 |
| 10 | Amplitude-frequency-aware deep fusion network for optimal contact selection on STN-DBS electrodes显示文摘Parkinson’s disease(PD)is treated effectively by deep brain stimulation(DBS)of the subthalamic nucleus(STN),using an electrode inserted into the head of a PD patient.The electrode has multiple electrical contacts along its length,so the best may be chosen for selectively stimulating the STN.Neurosurgeons usually determine the optimal stimulated contact via the clinical experience of the neurosurgeon and the motor improvement of PD patients.This is a time-consuming and labor-intensive trial-and-error process.The selection of optimal stimulated contact highly depends on the locations of sweet spots,which are manually identified by the characteristic features of microelectrode recordings(MERs).This paper presents an amplitude-frequency-aware deep fusion network for optimal contact selection on STN-DBS electrodes.The method first obtains the amplitude-frequency fusion features by combining the MERs time sequence features and the amplitude sequence features,and then uses the convolutional neural network(CNN)with convolutional block attention module(CBAM)to identify both the border of the STN and the sweet spots to implant the electrode.The optimal stimulated contact can be selected according to the distribution of the sweet spots.Experimental results indicate that,for successful surgeries,neurosurgeons and the proposed AI solution selected the same optimal contacts.Furthermore,the proposed method outperforms the state-of-the-art methods for STN and sweet spot identification.The proposed method shows great potential for optimal contact selection to improve the efficiency of STN-DBS surgery and reduce the dependence on clinicians’experience. | Linxia XIAO Caizi LI Yanjiang WANG Weixin SI Hai LIN Doudou ZHANG Xiaodong CAI Pheng-Ann HENG | 2022 | Science China(Information Sciences)2022，65，4： | 0 |
| 11 | Analysis on a Cold Wave Weather Process in Winter in Gansu显示文摘[Objective]The research aimed to analyze a cold wave weather process in winter in Gansu.[Method] Based on routine observation data and numerical forecast products,formation reason and physical quantity characteristics of a cold wave process during 2-5 December,2008 were comprehensively analyzed by synoptic analysis and diagnostic analysis methods.[Result]The cold wave weather belonged to ' translot turning vertical type'.Collapse of the Urals ridge,turning vertical of the translot and strengthening south of the ground cold high induced the cold wave.Development of the Siberian low vortex drove the small branch of cold air in polar region supplementing south,playing certain promoting role in outbreak of the cold wave.Physical quantities in the cold wave process also had very good expression,such as vorticity,temperature advection,etc.[Conclusion]This research had important indication effect for early warning,forecast and decision service of the future similar weather process. | SUN Yu-lian 1,2,ZHANG Shu-fang 2,ZHANG Li-lu 3,HUANG Cheng-xiu 2,HE Yu-chun 2 1.Lanzhou Institute of Arid Meteorology,China Meteorological Administration,Lanzhou 730020,China 2.Linxia Meteorological Bureau in Gansu,Linxia 731100,China 3.Yongjing Meteorological Bureau in Linxia of Gansu,Yongjing 731600,China | 2011 | Meteorological and Environmental Research2011，2，11： | 0 |
| 12 | Design of A 1.2 V Low-Power Clock Generator显示文摘 | Xu Zhuang Yu HuiYue Zhang Hui LinXia | 2011 | 半导体技术2011，36，12： | 0 |
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