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Synthetic auxotrophs accelerate cell factory development through growth-coupled models

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Frontiers of Chemical Science and Engineering 2024年第9期18卷 73-87页

作者： Liangpo Li Linwei Yu Xinxiao sun.Qipeng Yuan Xiaolin Shen jia Wang State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China

The engineering of microbial cell factories for the production of high-value chemicals from renewable resources presents several challenges,including the optimization of key enzymes,pathway fluxes and metabolic *** these challenges involves the development of synthetic auxotrophs,a strategy that links cell growth with enzyme properties or biosynthetic *** linkage allows for the improvement of enzyme properties by in vivo directed enzyme evolution,the enhancement of metabolic pathway fluxes under growth pressure,and remodeling of metabolic networks through directed strain *** advantage of employing synthetic auxotrophs lies in the power of growth-coupled selection,which is not only high-throughput but also labor-saving,greatly simplifying the development of both strains and *** auxotrophs play a pivotal role in advancing microbial cell factories,offering benefits from enzyme optimization to the manipulation of metabolic networks within single ***,this strategy extends to coculture systems,enabling collaboration within microbial *** review highlights the recently developed applications of synthetic auxotrophs as microbial cell factories,and discusses future perspectives,aiming to provide a practical guide for growth-coupled models to produce value-added chemicals as part of a sustainable biorefinery.

关键词： synthetic auxotrophs growth-coupled directed enzyme evolution pathway flux directed strain evolution coculture

Univariate Time Series Anomaly Detection Based on Hierarchical Attention Network

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Tsinghua Science and Technology 2024年第4期29卷 1181-1193页

作者： Zexi Chen Dongqiang jia Yushu sun.Lin Yang Wenjie Jin Ruoxi Liu State Grid Beijing Electric Power Company Beijing 100031China Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China

In order to support the perception and defense of the operation risk of the medium and low voltage distribution system, it is crucial to conduct data mining on the time series generated by the system to learn anomalous patterns, and carry out accurate and timely anomaly detection for timely discovery of anomalous conditions and early alerting. And edge computing has been widely used in the processing of Internet of Things (IoT) data. The key challenge of univariate time series anomaly detection is how to model complex nonlinear time dependence. However, most of the previous works only model the short-term time dependence, without considering the periodic long-term time dependence. Therefore, we propose a new Hierarchical Attention Network (HAN), which introduces seven day-level attention networks to capture fine-grained short-term time dependence, and uses a week-level attention network to model the periodic long-term time dependence. Then we combine the day-level feature learned by day-level attention network and week-level feature learned by week-level attention network to obtain the high-level time feature, according to which we can calculate the anomaly probability and further detect the anomaly. Extensive experiments on a public anomaly detection dataset, and deployment in a real-world medium and low voltage distribution system show the superiority of our proposed framework over state-of-the-arts.

关键词： edge computing anomaly detection univariate time series self-attention

Special Unipotent Representations of Simple Linear Lie Groups of Type A

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Acta Mathematica Sinica,English Series 2024年第3期40卷 707-716页

作者： Dan BARBASCH jia Jun MA Bin Yong sun.Chen Bo ZHU Department of Mathematics Cornell UniversityIthacaNY 14853USA School of Mathematical Sciences Xiamen UniversityXiamen 361005P.R.China Department of Mathematics Xiamen University Malaysia CampusSepangSelangor Darul Ehsan43900Malaysia Institute for Advanced Study in Mathematics&New Cornerstone Science Laboratory Zhejiang UniversityHangzhou 310058P.R.China Department of Mathematics National University of Singapore10 Lower Kent Ridge RoadSingapore 119076

Let G be a special linear group over the real,the complex or the quaternion,or a special unitary *** this note,we determine all special unipotent representations of G in the sense of Arthur and Barbasch-Vogan,and show... 详细信息

关键词： Special unipotent representations unitary representations coherent continuation Weyl group representations

Research on the generation method of seawater sound velocity model based on Perlin noise

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Acta Oceanologica Sinica 2024年第1期43卷 99-111页

作者： Zhimiao chang Fuxing Han Zhangqing sun.Zhenghui Gao Xueqiu Wang College of Geoexploration Science and Technology Jilin UniversityChangchun 130026China

In the processing of conventional marine seismic data,seawater is often assumed to have a constant velocity ***,due to static pressure,temperature difference and other factors,random disturbances may often frequently in seawater *** impact of such disturbances on data processing results is a topic of theoretical *** seawater sound velocity is a difficult physical quantity to measure,there is a need for a method that can generate models conforming to seawater *** article will combine the Munk model and Perlin noise to propose a two-dimensional dynamic seawater sound velocity model generation method,a method that can generate a dynamic,continuous,random seawater sound velocity model with some regularity at large ***,the paper discusses the influence of the inhomogeneity characteristics of seawater on wave field propagation and *** results show that the seawater sound velocity model with random disturbance will have a significant influence on the wave field simulation and imaging results.

关键词： Munk model Perlin noise seawater inhomogeneity

Effects of serum inflammatory factors,health index and disease activity scores on ankylosing spondylitis patients with sleep disorder

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World Journal of Psychiatry 2024年第6期14卷 866-875页

作者： Hui Wang jia-Ying sun.Yue Zhang Department of Rheumatology and Immunology The First Affiliated Hospital of Harbin Medical UniversityHarbin 150001Heilongjiang ProvinceChina

BACKGROUND Patients with ankylosing spondylitis(AS)frequently suffer from comorbid sleep disorders,exacerbating the burden of the disease and affecting their quality of *** To investigate the clinical significance of serum inflammatory factors,health index and disease activity scores in patients with AS complicated by sleep *** A total of 106 AS patients with comorbid sleep disorders were included in the *** patients were grouped into the desirable and undesirable prognosis groups in accordance with their clinical *** serum levels of inflammatory factors,including C-reactive protein,erythrocyte sedimentation rate,interleukin(IL)-6,tumour necrosis factor-αand IL-1β,were *** activity scores,such as the Bath AS functional index,Bath AS disease activity index,Bath AS metrology index and AS disease activity score,were *** health index was obtained through the Short Form-36 *** The study found significant associations amongst serum inflammatory factors,health index and disease activity scores in AS patients with comorbid sleep *** correlations were found between serum inflammatory factors and disease activity scores,indicating the influence of heightened systemic inflammation on disease severity and functional ***,negative correlations were found between disease activity scores and health index parameters,highlighting the effect of disease activity on various aspects of healthrelated quality of *** regression analysis further confirmed the predictive value of these factors on patient outcomes,underscoring their potential utility in risk assessment and *** The findings demonstrate the intricate interplay amongst disease activity,systemic inflammation and patientreported health outcomes in AS patients complicated by sleep *** results emphasise the need for comprehensive care strategies that address the diverse needs and challe

关键词： Inflammatory factors Disease activity scores Health index Ankylosing spondylitis Sleep disorders

Si/TiO2 carbon fiber core encapsulated in hierarchical multiple MXene@Co-MoS2 shells for constructing a free-standing anode of lithium storage

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Rare Metals 2024年第9期43卷 4222-4233页

作者： Xian-ping Du Ying Huang jia-ming Wang Zhen-he Feng Xu sun MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions School of Chemistry and Chemical Engineering Northwestern Polytechnical University Shanghai Institute of Space Power-Sources Ningbo Institute of Northwestern Polytechnical University

Silicon-based（Si-based） materials offer more possibilities for generating new portable electronic devices due to their high specific capacities. However, their inferior electrical conductivity and volume expansion during cycling seriously limit their development. The optimum solution is to select specific materials to establish an exceptionally conductive and volume buffer structure,which can assist Si materials in developing their excellent lithium storage properties. In this study, Si particles were confined in TiO2carbon fibers（TiO2CFs） via electrospinning, after which they were encapsulated with MXene and Co-MoS2（CMS） nanosheets to fabricate hierarchical ST-2@MXene@CMS films. TiO2CF, MXene and CMS were employed to establish a coherent conductive network with one-, two-and three-dimensional electronic pathways to permit the unimpeded flow of electrons inside the electrode material. TiO2CF, MXene and CMS acted precisely as multilayered buffers to ameliorate the volume change of Si particles during cycling. In addition, the CMS nanosheets were involved in lithium storage, contributing to the final electrochemical performance. Ultimately, the ST-2@MXene@CMS films served as free-standing electrodes, avoiding the impact of inactive interfaces on the electrochemical performance and fulfilling the lightweight requirement for new energy storage devices.

关键词： Co-MoS2 nanosheets Hierarchical structure Lithium-ion batteries MXene Si particles

Anion competition for Li^(+)solvated coordination environments in poly(1,3 dioxolane)electrolyte to enable high-voltage lithium metal solid-state batteries

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Journal of Energy Chemistry 2024年第9期96卷 633-641页

作者： Qiujun Wang Yanqiang Ma Xiaomeng jia Di Zhang Zhaojin Li Huilan sun.Qujiang sun.Bo Wang Li-Zhen Fan Hebei Key Laboratory of Flexible Functional Materials School of Materials Science and EngineeringHebei University of Science and TechnologyShijiazhuang 050000HebeiChina Beijing Advanced Innovation Center for Materials Genome Engineering Institute of Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China

Gel-based polymer electrolytes are limited by the polarity of the residual solvent,which restricts the coupling-breaking behaviour during Li^(+)conduction,resulting in the Li^(+)transport kinetics being greatly ***,we designed anion competitive gel polymer electrolyte(ACPE)by introducing lithium difluoro(oxalato)borate(LiDFOB)anion into the 1,3-dioxolane(DOL)in situ polymerisation *** enhances the ionic dipole interaction between Li^(+)and the solvent molecules and synergizes with Li^(+)across the solvation site of the polymer ethylene oxide(EO)unit,combination that greatly improves the Li^(+)transport *** a result,ACPE exhibits 1.12 mS cm^(−1)ionic conductivity and 0.75 Li^(+)transfer number at room ***,this intra-polymer solvation sheath allows preferential desolvation of DFOB−,which contributes to the formation of kinetically stable anion-derived interphase and effectively mitigates side *** results demonstrate that the assembled Li||NCM622 solid-state battery exhibits lifespan of over 300 cycles with average Coulombic efficiency of 98.8%and capacity retention of 80.3%.This study introduces a novel approach for ion migration and interface design,paving the way for high-safety and high-energy-density batteries.

关键词： Li-metal batteries Poly(1,3-dioxolane) In situ polymerization Solid-state polymer electrolytes Anion competition

Significantly Enhanced Melt Memory Effect of Metallocene-made Isotactic Polypropylene Containing Talc

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Chinese Journal of Polymer Science 2024年第2期42卷 213-222,I0008页

作者： Hong-Wen sun.Fu-Shan Wang Yan Gao Fu-Qing Wei jia-Chun Feng State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan UniversityShanghai200433China Lanzhou Petrochemical Corporation of PetroChina Lanzhou730060China Lanzhou Petrochemical Research Center Petrochemical Research Institute of PetroChinaLanzhou730060China

The melt memory effect is a widely observed phenomenon in semi-crystalline polymers. In practical applications, various additives are usually introduced into polymers, which may affect their melt memory behavior. In this work, the effect of talc on the melt memory effect of metallocene-made isotactic polypropylene(M-PP) was investigated in detail by using the differential scanning calorimetry. The results indicated that the introduction of talc significantly strengthened the melt memory effect of M-PP. Specifically, the upper limit temperature of Domain II increased from 161 ℃ to 174 ℃, resulting in a substantial widening of the temperature range of Domain IIa from 1 ℃ to 14 ℃. Analysis of the crystal orientation of the M-PP containing talc cooled from various Ts suggested that the remarkably enhanced melt memory effect could be ascribed to the stabilization of oriented nuclei facilitated by talc. This stabilizing effect was likely attributable to the prefreezing effect or the sorption interaction between talc and the M-PP chains.

关键词： Metallocene-made isotactic polypropylene Talc Melt memory effect Crystal orientation

Effects of 1-methylcyclopropene on skin greasiness and quality of'Yuluxiang'pear during storage at 20℃

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Journal of Integrative Agriculture 2024年第7期23卷 2476-2490页

作者： Wanting Yu Xinnan Zhang Weiwei Yan Xiaonan sun.Yang Wang Xiaohui jia Research Institute of Pomology Chinese Academy of Agricultural SciencesXingcheng 125100China

During storage at 20℃,specific pear cultivars may exhibit a greasy texture and decline in quality due to fruit *** these varieties,‘Yuluxiang’is particularly susceptible to peel greasiness,resulting in significant economic ***,there is an urgent need for a preservative that can effectively inhibit the development of *** studies have demonstrated the efficacy of 1-methylcyclopropene(1-MCP)in extending the storage period of *** hypothesize that it may also influence the occurrence of postharvest peel greasiness in the‘Yuluxiang’*** this study,we treated‘Yuluxiang’pears with *** stored them at 20℃while analyzing the composition and morphology of the surface waxes,recording enzyme activities related to wax synthesis,and measuring indicators associated with fruit storage quality and physiological *** results demonstrate that prolonged storage at 20℃leads to a rapid increase in skin greasiness,consistent with the observed elevations in L^(*),greasiness score,and the content of total wax and greasy wax ***,there were indications that cuticular waxes underwent melting,resulting in the formation of an amorphous *** comparison to controls,the application of 1-MCP significantly inhibited increments in L^(*) values as well as grease scores while also reducing accumulation rates for oily waxes throughout most stages over its shelf period,additionally delaying transitions from flaky-wax structures towards their amorphous *** the initial 7 d of storage,several enzymes involved in the biosynthesis and metabolism of greasy wax components,including lipoxygenase(LOX),phospholipase D(PLD),andβ-ketoacyl-CoA synthase(KCS),exhibited an increase followed by a subsequent *** activity of LOX during early shelf life(0–7 d)and the KCS activity during middle to late shelf life(14–21 d)were significantly suppressed by ***,1-MCP effectively maintained firmness,

关键词： ‘Yuluxiang’pear skin greasiness 1-methylcyclopropene storage quality