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A single-domain protein catenane of dihydrofolate reductase

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National Science Review 2023年第11期10卷 128-137页

作者： Jing Fang Tianzuo Li Jiyeon Lee Dahye Im lianjie xu Yajie Liu Jongcheol Seo Wen-Bin Zhang Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry & Physics of Ministry of EducationCenter for Soft Matter Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking University Department of Chemistry Pohang University of Science and Technology (POSTECH) Beijing Academy of Artificial Intelligence

A single-domain protein catenane refers to two mechanically interlocked polypeptide rings that fold synergistically into a compact and integrated structure, which is extremely rare in nature. Here, we report a single-domain protein catenane of dihydrofolate reductase(cat-DHFR). This design was achieved by rewiring the connectivity between secondary motifs to introduce artificial entanglement and synthesis was readily accomplished through a series of programmed and streamlined post-translational processing events in cells without any additional in vitro reactions. The target molecule contained few exogenous motifs and was thoroughly characterized using a combination of ultra-performance liquid chromatography–mass spectrometry, sodium dodecyl sulfate–polyacrylamide gel electrophoresis, protease cleavage experiments and ion mobility spectrometry–mass spectrometry. Compared with the linear control, cat-DHFR retained its catalytic capability and exhibited enhanced stability against thermal or chemical denaturation due to conformational restriction. These results suggest that linear proteins may be converted into their concatenated single-domain counterparts with almost identical chemical compositions, well-preserved functions and elevated stabilities, representing an entirely new horizon in protein science.

关键词： cellular synthesis catenane protein domain chemical topology DHFR

Topology: a unique dimension in protein engineering

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Science China Chemistry 2018年第1期61卷 3-16页

作者： lianjie xu Wen-Bin Zhang Key Laboratory of Polymer Chemistry & Physics of Ministry of Education Center for Soft Matter Science and EngineeringCollege of Chemistry and Molecular Engineering Peking University

Controlling protein topology has been a long standing challenge to go beyond their linear configuration defined by the translation mechanism of cellular machinery. In this mini-review, we focus on the topological diversity in proteins and review the major categories of protein topologies known to date, including branched/star proteins, circular proteins, lasso proteins, knotted proteins,and protein catenanes. The discovery of these topologically complex natural proteins and their synthetic pathways, the rational design and recombinant synthesis of artificial topological proteins and their biophysical studies, are summarized and discussed with regard to their general features and broad implications. The complexity of protein topology is recognized and the routes to diverse protein topologies are illustrated. We believe that topology engineering is an important way to modify protein properties without alternating their native sequences and shall bring in valuable dynamic features central to the creation of artificial protein machinery.

关键词： protein topology protein engineering catenane rotaxane knot lasso peptide

加权核范数最小化和改进小波阈值函数的图像去噪算法

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国防科技大学学报 2024年第2期46卷 238-246页

作者：郭昕刚许连杰程超霍金花长春工业大学计算机科学与工程学院吉林长春130012

针对加权核范数最小化算法存在结构残余噪声以及无法较好地保持图像边缘结构的问题,提出基于加权核范数最小化和改进小波阈值函数的图像去噪算法。利用全变分模型对噪声图像进行初步去噪,使用噪声图像与初步去噪后的图像进行差分运算,... 详细信息

针对加权核范数最小化算法存在结构残余噪声以及无法较好地保持图像边缘结构的问题,提出基于加权核范数最小化和改进小波阈值函数的图像去噪算法。利用全变分模型对噪声图像进行初步去噪,使用噪声图像与初步去噪后的图像进行差分运算,对差分后得到的噪声残差图像使用改进的小波阈值函数去噪,将小波去噪后的残差图像与初步去噪图像叠加,将叠加后的图像使用基于残余噪声水平迭代的加权核范数最小化算法进行二次去噪。相较于当下主流去噪算法,经该算法处理后的图像的PSNR和SSIM值均有所提升,能够更好地保持图像的纹理结构,且在高噪声环境下效果更佳。

关键词：加权核范数小波变换噪声残差全变分

Native conjugation between proteins and [60]fullerene derivatives using SpyTag as a reactive handle

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Chinese Chemical Letters 2021年第1期32卷 353-356页

作者： Guangzhong Yin Jingjing Wei Yu Shao Wen-Hao Wu lianjie xu Wen-Bin Zhang Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry and Physics of the Ministry of EducationCollege of Chemistry and Molecular EngineeringCenter for Soft Matter Science and EngineeringPeking UniversityBeijing 100871China College of Chemical and Environmental Engineering Anyang Institute of TechnologyAnyang 455000China

Herein,we report the facile conjugation between proteins and water-soluble [60]fullerene derivatives(DC_(60)) under native conditions using SpyTag as a reactive handle.Water-soluble [60] fullerene derivatives were first prepared via sequential Bingel-Hirsch reaction and "clicked" with SpyTag to give DC_(60)-SpyTag for native conjugation with proteins by the highly efficient SpyTag-SpyCatcher chemistry.The bioconjugation was confirmed by MALDI-TOF MS spectra and SDS-PAGE analysis.The TEM and UVvis spectroscopic study further revealed that the DC_(60) could alter the optical performance and induce aggregation of the target proteins.It thus provides a general and robust method for modifying proteins with C_(60) derivatives and could potentially be adapted for native conjugation between proteins and other nonbiological motifs as well.

关键词： SpyTag Spy Catcher Fullerene Protein Bioconjugate

Energy-saving design and optimization of pressure-swing-assisted ternary heterogenous azeotropic distillations

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Chinese Journal of Chemical Engineering 2024年第4期68卷 1-7页

作者： lianjie Wu Kun Lu Qirui Li Lianghua xu Yiqing Luo Xigang Yuan Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion College of Chemical and Chemical EngineeringTianjin University of TechnologyTianjin 300384China State Key Laboratory of Chemical Engineering Tianjin UniversityTianjin 300072China

A huge amount of energy is always consumed to separate the ternary azeotropic mixtures by distillations.The heterogeneous azeotropic distillation and the pressure-swing distillation are two kinds of effective technologies to separate heterogeneous azeotropes without entrainer addition.To give better play to the synergistic energy-saving effect of these two processes,a novel pressure-swing-assisted ternary heterogeneous azeotropic distillation(THAD)process is proposed firstly.In this process,the ternary heterogeneous azeotrope is decanted into two liquid phases before being refluxed into the azeotropic distillation column to avoid the aqueous phase remixing,and three columns'pressures are modified to decrease the flowrates of the recycle streams.Then the dividing wall column and heat integration technologies are introduced to further reduce its energy consumption,and the pressureswing-assisted ternary heterogeneous azeotropic dividing-wall column and its heat integration structure are achieved.A genetic algorithm procedure is used to optimize the proposed processes.The design results show that the proposed processes have higher energy efficiencies and lower CO_(2)emissions than the published THAD process.

关键词： Distillation Separation Process control Process systems

Newspaper coverage of tobacco issues: an analysis of print news in Chinese cities, 2008-2011

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Newspaper coverage of tobacco issues: an analysis of print n...

KL散度多模块滑动窗口慢特征分析的故障诊断方法

第八届中国健康传播大会

作者： Siwei He Qin Shen Xiaoli Yin lianjie xu Xiaoyun Lan Xiangya School of Medicine Central South University Xiangya Hospital Central-South University

Objective The purpose of this study was to determine to what extent Chinese media coverage of tobacco issues in 17 Chinese cities comprises messaging known to motivate healthy behaviour. Methods This study involved a content analysis of4821 articles that contained at least one full paragraph focused on tobacco issues from newspapers published in cities that participated in the Tobacco-Free City-Gates Tobacco Control Project in China between 1 January 2008 and 30 June 2011. Results The number of tobacco-focused articles increased over the study period. The number of articles varied considerably among different newspapers and cities. Education, prevention and cessation programs （35%） were the most frequent theme. There was also considerable variation in the volume of coverage each month. News articles were the most frequent article type （70%）. The majority of the articles （72%） were positive for tobacco control. There were significant differences between party newspapers and local newspapers in prominence, article type, slant and fear appeal. One quarter （n=729） of the articles mentioned the severity of tobacco use, while only 10% of the articles referred to susceptibility to the threat. Conclusions The coverage of events was predominantly positive toward tobacco control. However, media reports could better support tobacco control efforts if they did a better job at provoking an emotional response to the harms of tobacco use and promoting a sense among smokers that they can succeed in quitting smoking.

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国防科技大学学报 2023年第6期45卷 165-173页

作者：郭昕刚霍金花程超许连杰长春工业大学计算机科学与工程学院吉林长春130012

针对传统分块方法根据经验划分子块导致变量特征信息无法充分利用,其单一的建模方式忽略局部信息以及离线模型无法适应时变特性的问题,提出了一种KL (Kullback-Leibler)散度多模块滑动窗口慢特征分析方法。在正常工况数据集中,利用KL散... 详细信息

针对传统分块方法根据经验划分子块导致变量特征信息无法充分利用,其单一的建模方式忽略局部信息以及离线模型无法适应时变特性的问题,提出了一种KL (Kullback-Leibler)散度多模块滑动窗口慢特征分析方法。在正常工况数据集中,利用KL散度来度量变量间的距离,同时引入最小误差平方和准则进行聚类,分成两个距离最小的子模块;在此基础上利用慢特征分析方法对每个子模块进行建模,结合滑动窗口对每次采样的数据进行更新,得到最优模型,分别计算监测统计信息,利用支持向量数据描述对故障监测结果进行融合,实现故障诊断。并将该方法应用于田纳西伊斯曼过程的监控中,得到了较高的故障检测率和较低的虚警率,验证了该方法的可行性和有效性。

关键词： KL散度滑动窗口慢特征分析故障诊断

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一种简易快速装夹轴类零件钻削夹具设计

科学技术创新 2022年第35期 173-176页

作者：许连杰苏州健雄职业技术学院江苏太仓215400

企业生产中,往往夹具的一点点优化便可以改进产品的生产工艺,进而降低生产成本。在轴类零件端面孔的加工中,因为孔的定位要求,无法使用普通钻床加工,需要使用数控设备加工。但产品结构简单,使用数控设计加工的话经济效益较低。因此设计... 详细信息

企业生产中,往往夹具的一点点优化便可以改进产品的生产工艺,进而降低生产成本。在轴类零件端面孔的加工中,因为孔的定位要求,无法使用普通钻床加工,需要使用数控设备加工。但产品结构简单,使用数控设计加工的话经济效益较低。因此设计一种夹具,使之能够使用普通钻床加工,且装夹方便快捷。

关键词：夹具设计快速装夹钻削凸轮

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基于时间序列融合的室内定位方法

数据采集与处理 2024年第3期39卷 750-760页

作者：余莲杰李建峰徐睿张小飞南京航空航天大学电子信息工程学院南京211106

提出了一种基于拉依达准则-相关系数-卷积神经网络(Pauta criterion-correlation coefficient-convolutional neural networks,P-C-CNN)的时间序列融合定位算法。P-C-CNN方法整合了不同节点以及不同时间序列的数据点,利用时间和空间数... 详细信息

提出了一种基于拉依达准则-相关系数-卷积神经网络(Pauta criterion-correlation coefficient-convolutional neural networks,P-C-CNN)的时间序列融合定位算法。P-C-CNN方法整合了不同节点以及不同时间序列的数据点,利用时间和空间数据的相互关联性,提高了室内定位的精度和可靠性。首先,该方法使用拉依达准则-相关系数(Pauta criterion-correlation coefficient,P-C)算法对到达角度(Angle of arrival,AOA)-接收信号强度(Received signal strength,RSS)数据的异常值进行剔除,提高了训练数据的质量。其次,算法对数据进行随机间隔选取,从而缩短模型训练时间,同时较好地模拟在线定位阶段数据选取的不确定性,减少模型对训练数据的过度拟合。再次,传统单帧信息训练方法由于噪声混杂无法稳定提取信息特征,所提算法在连续采集的时间序列数据中,融合随机选取固定长度的多帧AOA-RSS数据,然后利用卷积神经网络(Convolutional neural networks,CNN)进行特征提取,避免了单帧信号定位中误差波动较大的问题。最后,通过大量实际测试,验证了所提方法的有效性。实验结果表明,在典型室内环境中,与仅采用RSS数据或者AOA信息的指纹定位算法相比,本文算法的分类准确率由91.6%提高到了96.4%,定位精度从1.3 m提高到了0.3 m;与传统基于模型的AOA-RSS联合定位相比,本文算法能较好解决实测中多径效应等干扰因素的影响,定位精度从1.1 m提高到了0.3 m。

关键词：室内定位深度学习卷积神经网络联合定位时间序列