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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 | Application of a Novel Method for Machine Performance Degradation Assessment Based on Gaussian Mixture Model and Logistic Regression显示文摘The currently prevalent machine performance degradation assessment techniques involve estimating a machine's current condition based upon the recognition of indications of failure features,which entail complete data collected in different conditions.However,failure data are always hard to acquire,thus making those techniques hard to be applied.In this paper,a novel method which does not need failure history data is introduced.Wavelet packet decomposition(WPD) is used to extract features from raw signals,principal component analysis(PCA) is utilized to reduce feature dimensions,and Gaussian mixture model(GMM) is then applied to approximate the feature space distributions.Single-channel confidence value(SCV) is calculated by the overlap between GMM of the monitoring condition and that of the normal condition,which can indicate the performance of single-channel.Furthermore,multi-channel confidence value(MCV),which can be deemed as the overall performance index of multi-channel,is calculated via logistic regression(LR) and that the task of decision-level sensor fusion is also completed.Both SCV and MCV can serve as the basis on which proactive maintenance measures can be taken,thus preventing machine breakdown.The method has been adopted to assess the performance of the turbine of a centrifugal compressor in a factory of Petro-China,and the result shows that it can effectively complete this task.The proposed method has engineering significance for machine performance degradation assessment. | LIU Wenbin ZHONG Xin LEE Jay LIAO Linxia ZHOU Min | 2011 | Chinese Journal of Mechanical Engineering2011，24，5： | 3 |
| 4 | 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 |
| 5 | Molecular modulating of cobalt phthalocyanines on aminofunctionalized carbon nanotubes for enhanced electrocatalytic CO_(2)conversion显示文摘Metal porphyrins and metal phthalocyanines(Pc)constitute a promising class of metal molecular catalysts(MMCs)for efficient CO_(2)-to-CO electrocatalytic conversion due to their well-defined molecular structures.How to adjust the local coordination and electronic environment of the metal center and enhance the molecular-level dispersion of the active components remains as great challenges for further improving the performance.Herein,a cobalt(II)Pc(CoPc)-COOH/carbon nanotube(CNT)-NH_(2)hybrid catalyst was rationally designed by clicking the CoPc-COOH molecules onto the surface of CNT-NH_(2)through amidation reaction.This novel hybrid catalyst exhibited the enhanced current density of 22.4 mA/cm2 and CO selectivity of 91%at−0.88 V vs.reversible hydrogen electrode(RHE)in the CO_(2)electroreduction,as compared with CoPc-COOH/CNT and CoPc/CNT samples.The superior activity was ascribed to the charge transfer induced by introduction of-COOH and-NH_(2)functional groups to CoPc and CNT,respectively,facilitating the active centers of CoI being generated at lower potentials,and leading to the highest turnover frequency(TOF)being obtained over the CoPc-COOH/CNT-NH_(2)hybrid catalyst.The inherent directivity and saturability of covalent bonds formed via the amidation reaction ensure not only a higher density of Co active centers,but also an improved stability for CO_(2)reduction reaction(CO_(2)RR).The present study represents an effective strategy for improving MMCs performance by molecular modulating of metal phthalocyanines on functionalized carbon substrates directed by click confinement chemistry. | Huajian Xu Huizhu Cai Linxia Cui Limei Yu Rui Gao Chuan Shi | 2023 | Nano Research2023，16，3： | 2 |
| 6 | Preparation of basic lead oxide from spent lead acid battery paste via chemical conversion显示文摘 | Xinfeng Zhu Lei Li Xiaojuan Sun Danni Yang Linxia Gao Jianwen Liu R. Vasant Kumar Jiakuan Yang | 2012 | Hydrometallurgy2012，，： | 2 |
| 7 | Preparation, prop- erties and applications of polypyrtoles 显示文摘 | Wang Linxia Li Xingui Yang Yuliang | 2001 | Reactive and Functional Polymers2001，47，2： | 1 |
| 8 | A novel method for machine performance degradation assessment based on fixed cycle features test 显示文摘 | LIAO Linxia | 2009 | Journal of Sound and Vibration2009，323，： | 1 |
| 9 | 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 |
| 10 | Global asymp- totic behavior of a rational difference equation 显示文摘 | HU linxia HE wansheng XIA hongming | 2012 | Appl Math Comput2012，218，15： | 1 |
| 11 | Preparation of basic lead oxide from spent lead acid battery paste via chemical conversion显示文摘 | Xinfeng Zhu Lei Li Xiaojuan Sun Danni Yang Linxia Gao Jianwen Liu R. Vasant Kumar Jiakuan Yang | 2012 | Hydrometallurgy2012，，： | 1 |
| 12 | Effect of iron doped lead oxide on the performance of lead acid batteries显示文摘 | Jianwen Liu Danni Yang Linxia Gao Xinfeng Zhu Lei Li Jiakuan Yang | 2011 | Journal of Power Sources2011，，： | 1 |
| 13 | Preparation and characterization of nano-structured lead oxide from spent lead acid battery paste显示文摘 | Lei Li Xinfeng Zhu Danni Yang Linxia Gao Jianwen Liu R. Vasant Kumar Jiakuan Yang | 2011 | Journal of Hazardous Materials2011，，： | 1 |
| 14 | Synthesis and characterization of pyrrole and anisidine copolymers显示文摘 | LI Xingui HUANG Meirong WANG Linxia | 2001 | Polymer2001，42，14： | 1 |
| 15 | Synthesis and characterization of pyrrole and m-toluidine copolymers 显示文摘 | LI Xingui HUANG Meirong WANG Linxia | 2001 | Synthetic Metals2001，123，3： | 1 |
| 16 | Preparation of lead carbonate from spent lead paste via chemical conversion显示文摘 | Zhu Xinfeng Yang Jiakuan Gao Linxia | 2013 | Hydrometallurgy2013，，： | 1 |
| 17 | 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 |
| 18 | Preparation of lead carbonate from spent lead paste via chemical conversion 显示文摘 | Zhu Xinfeng Yang Jiakuan Gao Linxia | 2013 | Hy- drometallurgy2013，，： | 1 |
| 19 | A novel method for machine performancedegradation assessment based on fixed cycle featurestest显示文摘 | Liao Linxia | 2009 | Journal of Sound and Vibration2009，323，： | 1 |
| 20 | A cyclin protein governs the infectious and sexual life cycles of Cryptococcus neoformans显示文摘Cell cycle is a fundamental process underlying growth and development in evolutionarily diverse organisms, including fungi. In human fungal pathogens, cell cycle control generally determines their life cycles, either in the environment or during infections.Thus, cell cycle components can potentially serve as important targets for the development of antifungal strategy against fungal infections. Here, in Cryptococcus neoformans, the most common cause of fatal fungal meningitis, we show that a previously uncharacterized B-type cyclin named Cbc1 is essential for both its infectious and sexual cycles. We reveal that Cbc1 coordinates various sexual differentiation and molecular processes, including meiosis. Especially, the absence of Cbc1 abolishes formation of sexual spores in C. neoformans, which are presumed infectious particles. Cbc1 is also required for the major Cryptococcus pathogenic attributes. Virulence assessment using the murine model of cryptococcosis revealed that the cbc1 mutant is avirulent.Together, our results provide an important insight into how C. neoformans employs shared cell cycle regulation to coordinate its infectious and sexual cycles, which are considered crucial for virulence evolution and the production of infectious spores. | Pengjie Hu Linxia Liu Weixin Ke Xiuyun Tian Linqi Wang | 2021 | Science China(Life Sciences)2021，64，8： | 1 |
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