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Construction of a sustainable 3-hydroxybutyrate-producing probiotic Escherichia coli for treatment of colitis

Cellular & Molecular Immunology 2021年第10期18卷 2344-2357页

作者： Xu Yan Xin-Yi Liu dian Zhang Yu-dian Zhang Zi-Hua Li Xu Liu Fuqing Wu Guo-qiang Chen Center for Synthetic and Systems Biology Tsinghua UniversityBeijingChina School of Life Sciences Tsinghua UniversityBeijingChina MOE Key Lab for Industrial Biocatalysis Dept.Chemical EngineeringTsinghua UniversityBeijingChina

Colitis is a common disease of the colon that is very difficult to *** bacteria could be an effective *** probiotic Escherichia coli Nissle 1917(EcN)was engineered to synthesize the ketone body(R)-3-hydroxybutyrate(3HB)for sustainable production in the gut lumen of mice suffering from *** of heterologous 3HB synthesis routes were constructed,expressed,optimized,and inserted into the EcN genome,combined with deletions in competitive branch *** genome-engineered EcN produced the highest 3HB level of 0.6 g/L under microaerobic *** live therapeutic was found to colonize the mouse gastrointestinal tract over 14 days,elevating gut 3HB and short-chain-length fatty acid(SCFA)levels 8.7-and 3.1-fold compared to those of wild-type EcN,*** sustainable presence of 3HB in mouse guts promoted the growth of probiotic bacteria,especially Akkermansia spp.,to over 31%from the initial 2%of all the *** a result,the engineered EcN termed EcNL4 ameliorated colitis induced via dextran sulfate sodium(DSS)in *** to wild-type EcN or oral administration of 3HB,oral EcNL4 uptake demonstrated better effects on mouse weights,colon lengths,occult blood levels,gut tissue myeloperoxidase activity and proinflammatory cytokine ***,a promising live bacterium was developed to improve colonic microenvironments and further treat *** proof-of-concept design can be employed to treat other diseases of the colon.

关键词： Escherichia coli Nissle 1917 Colitis β-hydroxybutyrate 3HB Synthetic biology Metabolic engineering Microbiomes Probiotics Colonic microenvironment

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Effects of Surface Roughness on Interface Bonding Performance for 316H Stainless Steel in Hot-Compression Bonding

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Acta Metallurgica Sinica(English Letters) 2023年第5期36卷 771-788页

作者： Yong Zhao Bi-Jun Xie Jin-Long Zhang Qin-qiang wang Bin Xu Jiang Guo Zhu-Ji Jin Ren-Ke Kang dian-Zhong Li Key Laboratory for Precision and Non-Traditional Machining Technology of Ministry of Education Dalian University of TechnologyDalian116024China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

The metallurgical bonding quality of bonding joints is affected by the substrate surface state in hot-compression bonding(HCB),and the surface roughness is a core indicator of the surface ***,the effects of surface roughness on interface bonding performance(IBP)in the HCB process are unclear for substrates with refractory oxide *** study presents the effects of surface roughness on IBP for 316H stainless steel joints fabricated by HCB.A set of HCB parameters for interface bonding critical state of 316H stainless steel joints was *** HCB experiments were carried out under parameters of interface bonding critical state to amplify the effect of surface *** interface morphologies,element distribution,and tensile properties were used to characterize the *** a result,the formation mechanisms of the interface pits were revealed and the variation trend of pit number with the roughness was ***,the mapping relation between surface roughness and IBP was *** results show that the degree of rotational dynamic recrystallization becomes weaker with the decrease in the surface roughness and the interface bonding mechanism is completely transformed into discontinuous dynamic recrystallization when the roughness is lower than 0.020μm *** number of interfacial pits decreases as the roughness decreases owing to the weakening of oxide scale aggregation and abrasive inclusion *** elongation of the tensile specimen cannot increase significantly while the roughness is lower than 0.698μm Sa.

关键词： Surface roughness Interface bonding performance Hot-compression bonding Mapping relation Critical state

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基于遥感的1984一2019年查干湖及周边湖泊透明度变化

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湖泊科学 2025年第1期37卷 328-338页

作者：赵方睿王强穆春生刘阁温志丹陶慧宋开山东北师范大学生命科学学院长春130024 中国科学院东北地理与农业生态研究所长春130102

湖泊透明度是衡量水质变化和湖泊水生生态系统健康的重要指标。湖泊透明度一般通过塞氏盘现场观测获得,其变化主要由水体中非藻类颗粒物、藻类和黄色物质(CDOM)浓度共同决定,因此可以通过光学遥感进行反演。本研究基于20042009年8次查... 详细信息

湖泊透明度是衡量水质变化和湖泊水生生态系统健康的重要指标。湖泊透明度一般通过塞氏盘现场观测获得,其变化主要由水体中非藻类颗粒物、藻类和黄色物质(CDOM)浓度共同决定,因此可以通过光学遥感进行反演。本研究基于20042009年8次查干湖实地采样获得的132条透明度数据,通过分析同步Landsat天顶反射率产品数据(TOA)不同波段组合与透明度之间的相关性,发现以红波段和蓝波段比值和红绿蓝波段均值AV(B3,B1)组合建立的透明度反演模型精度最高,误差最小,进而基于此模型反演了19842019年查干湖以及周边湖泊透明度。结果表明:查干湖透明度范围在1.0~63.0 cm之间,年均值为17.6 cm。查干湖透明度年均值变化分为两个阶段:19842001年间透明度波动范围较大,没有明显趋势;20022019年期间呈上升趋势(2.3 cm/10 a)。查干湖透明度与风速、降水量、湖泊面积和归一化植被指数具有一定的相关性。通过长时间尺度上遥感监测查干湖水体透明度的时空格局变化,分析其变化特征与规律,可为查干湖流域生态治理提供科学依据。

关键词：查干湖透明度 Landsat 遥感

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Progress on deep circulation and meridional overturning circulation in the South China Sea

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Science China Earth Sciences 2016年第9期59卷 1827-1833页

作者： wang DongXiao XIAO JinGen SHU Yeqiang XIE qiang CHEN Ju wang qiang State Key Laboratory of Tropical Oceanography South China Sea Institute of Oceanology Chinese Academy of Sciences College of Earth Sciences University of Chinese Academy of Sciences Institute of Deep Sea Science and Engineering Chinese Academy of Sciences

The deep overflow through the Luzon Strait drives the cyclonic deep circulation in the South China Sea(SCS). In the mean time, the intruding Pacific deep water transforms and upwells due to enhanced diapycnal mixing in the SCS. Both processes greatly contribute to the SCS meridional overturning circulation(SCSMOC). At the same time, both the deep circulation and meridional overturning circulation are modulated by rough topography in the SCS. Furthermore, the spatial structure of the SCSMOC infers a link between the upper-layer circulation and deep circulation in the SCS. This paper reviews recent advances in the SCS deep circulation and meridional overturning circulation, including the driving mechanism of the SCS deep circulation and its modulation by topography, as well as the spatial structure of the SCSMOC and its dynamical mechanism.

关键词： Luzon overflow SCS deep circulation SCSMOC Topography

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采用小波变换的空间外差干涉图误差分析方法

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光谱学与光谱分析 2025年第1期45卷 8-14页

作者：王方原李晓静叶松李树王新强桂林电子科技大学光电工程学院广西桂林541004 广西光电信息处理重点实验室广西桂林541004

空间外差光谱技术(SHS)是一种应用于微弱物质探测、行星勘探以及大气遥感等领域的超光谱分析技术。受实验环境复杂及被测目标信号微弱等因素的影响,空间外差光谱仪的测量结果易出现干涉条纹倾斜、干涉图有斑点噪声等情况,从而最终影响... 详细信息

空间外差光谱技术(SHS)是一种应用于微弱物质探测、行星勘探以及大气遥感等领域的超光谱分析技术。受实验环境复杂及被测目标信号微弱等因素的影响,空间外差光谱仪的测量结果易出现干涉条纹倾斜、干涉图有斑点噪声等情况,从而最终影响测量光谱的精度。为了尝试解决这些问题,提出了基于小波变换的干涉图误差分析方法,对干涉图的斑点噪声水平和条纹倾斜误差进行有效的评价,从而为后续误差校正提供理论基础。首先对无误差的钾灯仿真干涉图加入不同标准差的高斯噪声,利用小波分解提取复小波系数,采用三种噪声估计法对干涉图数据进行计算,结果表明空域相关小波变换法噪声估计结果与真实值偏差最小,而Donoho估计法在修正截距后与真实值具有更好的吻合度。随后采用Db2小波对噪声水平不同的仿真钾灯干涉图进行一层小波分解并提取水平、对角及垂直三个方向的细节系数,采用Donoho估计法对干涉图进行二维噪声分析,有效表征了三幅干涉图各方向上的噪声水平特征。最后对仿真连续光干涉图进行小波分解并提取系数分析,研究了干涉条纹倾斜角度与小波分解系数的关系。研究结果表明,三个方向的小波细节系数估值变化分别在分解到不同层数时具有相似的变化规律:小波细节系数估值与条纹倾斜方向和小波细节系数的所属方向的夹角成反比,条纹倾斜方向与该小波细节系数的方向夹角越小,估值越大,反之则越小,且水平方向分解到第一层、对角方向分解到第二层、垂直方向分解到第三层符合变化规律。该研究是利用小波分解进行空间外差光谱误差分析的有益尝试,也为后续干涉图条纹倾斜误差的校正提供了一种新途径。

关键词：空间外差光谱技术噪声标准差估计干涉图小波变换

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A review of object representation based on local features

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Journal of Zhejiang University-Science C(Computers and Electronics) 2013年第7期14卷 495-504页

作者： Jian CAO dian-hui MAO qiang CAI Hai-sheng LI Jun-ping DU College of Computer and Information Engineering Beijing Technology and Business University School of Computer Science Beijing University of Posts and Telecommunications

Object representation based on local features is a topical subject in the domain of image understanding and computer vision. We discuss the defects of global features in present methods and the advantages of local features in object recognition, and briefly explore state-of-the-art recognition methods using local features, especially the main approaches of local feature extraction and object representation. To clearly explain these methods, the problem of local feature extraction is divided into feature region detection, feature region description, and feature space optimization. The main components and merits of these steps are presented. Technologies for object presentation are classified into three types: vector space, sliding window, and structure relationship models. Future development trends are discussed briefly.

关键词： Object presentation Local feature Image understanding Object recognition Visual words

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基于无人机多光谱数据和氮素空间分异的玉米冠层氮浓度估算

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作物学报 2025年第1期51卷 189-206页

作者：郝琪陈天陆王富贵王振白岚方王永强王志刚内蒙古农业大学农学院内蒙古呼和浩特010010

作物冠层氮素营养的遥感诊断对指导作物精准施氮,提高作物氮效率和产量具有重要意义。本研究针对玉米冠层纵深大影响无人机估算氮浓度精度的问题,基于2022年和2023年不同氮肥运筹处理下田间无人机多光谱数据和氮浓度实测数据,分析玉米... 详细信息

作物冠层氮素营养的遥感诊断对指导作物精准施氮,提高作物氮效率和产量具有重要意义。本研究针对玉米冠层纵深大影响无人机估算氮浓度精度的问题,基于2022年和2023年不同氮肥运筹处理下田间无人机多光谱数据和氮浓度实测数据,分析玉米冠层氮浓度空间分布特征,并利用随机森林算法确定估算冠层氮浓度的有效叶层。进一步结合随机森林算法和多光谱植被指数构建有效叶层氮浓度估算模型,最终将有效叶层氮浓度转换到冠层尺度实现冠层氮浓度的估算。结果表明:(1)九叶展期和大喇叭口期玉米冠层氮浓度表现为上层叶片>中层叶片>下层叶片,吐丝期和乳熟期表现为中层叶片>上层叶片>下层叶片。(2)各时期估算冠层氮浓度的有效叶层分别为下层、中层、中层和中层。与支持向量回归模型相比,随机森林回归估算冠层氮浓度的精度较高。(3)结合随机森林算法,基于有效叶层氮浓度估算冠层氮浓度的平均RMSE、NRMSE和MAE分别为0.10%、4.41%和0.07%,而直接基于植被指数估算冠层氮浓度的平均RMSE、NRMSE和MAE分别为0.19%、9.00%和0.15%。综上,玉米冠层氮浓度存在空间分异特征,估算冠层氮浓度时考虑基于随机森林和植被指数估算的有效叶层氮浓度能明显提高冠层氮浓度的估算精度。本研究确定的考虑空间分异的冠层氮浓度估算框架可为玉米氮素营养实时诊断提供理论支撑。

关键词：玉米冠层氮浓度氮素空间分异多光谱数据机器学习

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Effect of order–disorder transition on thermodynamic and electronic properties of σ and χ phases in W–Re alloy: the first-principles calculation

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Tungsten 2025年第1期 195-213页

作者： Zhi-Peng Zhu dian Jia William Yi wang Jun-Lei Yin Xing-Yu Gao Shu-Feng Yang Hai-Feng Song Jin-Shan Li State Key Laboratory of Solidification Processing Northwestern Polytechnical University Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The Tungsten-Rhenium(W-Re) alloys,celebrated for their high melting point,strength at elevated temperatures,electrical resistivity,and radiation resistance,have been widely utilized in high-temperature components,aerospace,electronics,and nuclear *** constituents of the topologically close-packed(TCP) phases,the sigma phase(σ) and chi phase(χ) formed within W-Re alloys wield considerable influence on the mechanical properties and the stability of the *** calculations were utilized in the present work to explore the structural,thermodynamic,and electronic properties of both ordered and disordered configurations within the σ and χ phases,culminating in a systematic elucidation of the higher phase stability exhibited by the ordered *** is found that the bulk modulus of these two phases is directly proportional to the concentration of Re in the alloy,while the equilibrium volume is inversely *** thermodynamic parameters of the σ and χ phases are calculated via the mean-field potential *** similar trends observed in the isobaric heat capacity,enthalpy increment,and entropy change curves for these two phases suggest they possess comparable thermodynamic *** is noteworthy that the contribution of ionic vibrations predominantly affects the isobaric heat capacity,while the contribution of thermal electronic excitations increases linearly with *** the structure and thermodynamic properties of TCP phases in W-Re alloys at low temperatures has profound significance for optimizing material performance,microstructures features,establishing theoretical foundations,and predicting material behavior.

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Impacts of emissions and meteorological changes on China’s ozone pollution in the warm seasons of 2013 and 2017

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Frontiers of Environmental Science & Engineering 2019年第5期13卷 129-137页

作者： dian Ding Jia Xing Shuxiao wang Xing Chang Jiming Hao State Key Joint Laboratory of Environmental Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Beijing 100084China

We have quantified the impacts of anthropogenic emissions reductions caused by the Air Pollution Control Action Plan and changes in meteorological fields between 2013 and 2017 on the warm-season O3 concentration in China using a regional 3D chemical transport model. We found that the impact on daily maximum eight-hour (MDA8) O3 concentration by the meteorological variation that mostly increased O3 was greater than that from emission reduction, which decreased O3. Specifically, the control measures implemented since 2013 in China have reduced SO2, NOx, PM2.5, and VOC emissions by 33%, 25%, 30%, and 4% in 2017, while NH3 emissions have increased by 7%. The changes in anthropogenic emissions lowered MDA8 O3 by 0.4–3.7 ppb (0.8%–7.6%, varying by region and month), although MDA8 O3 was increased slightly in some urban areas (i.e. North China) at the beginning/end of warm seasons. Relative to 2013, the average 2 m temperature in 2017 shows increments in North, North-east, East, and South China (0.34℃–0.83℃) and decreases in Central China (0.24℃). The average solar radiation shows increments in North, North-east, and South China (7.0–9.7 w/m2) and decreases in Central, South-west, and North-west China (4.7–10.3 w/m2). The meteorological differences significantly change MDA8 O3 by -3.5–8.5 ppb (-8.2%–18.8%) with large temporal variations. The average MDA8 O3 was slightly increased in North, North-east, East, and South China. The response surface model suggests that the O3 formation regime transfers from NOx-saturated in April to NOx-limited in July on average in China.

关键词： O3 pollution Meteorological influences Emission reduction NOx VOC

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Short-term traffic safety forecasting using Gaussian mixture model and Kalman filter

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第4期14卷 231-243页

作者： Sheng JIN dian-hai wang Cheng XU Dong-fang MA College of Civil Engineering and Architecture Zhejiang University Zhejiang Police College

In this paper,a prediction model is developed that combines a Gaussian mixture model(GMM) and a Kalman filter for online forecasting of traffic safety on *** time-to-collision(TTC) samples are divided into two categories:those representing vehicles in risky situations and those in safe ***,the GMM is used to model the bimodal distribution of the TTC samples,and the maximum likelihood(ML) estimation parameters of the TTC distribution are obtained using the expectation-maximization(EM) *** propose a new traffic safety indicator,named the proportion of exposure to traffic conflicts(PETTC),for assessing the risk and predicting the safety of expressway traffic.A Kalman filter is applied to forecast the short-term safety indicator,PETTC,and solves the online safety prediction problem.A dataset collected from four different expressway locations is used for performance *** test results demonstrate the precision and robustness of the prediction model under different traffic conditions and using different *** results could help decision-makers to improve their online traffic safety forecasting and enable the optimal operation of expressway traffic management systems.

关键词： Forecasting Traffic safety Gaussian mixture model Kalman filter

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