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Sequence analysis of peptides with biological activities using electrospray-Fourier transform ion cyclotron resonance mass spectrometry

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Chinese Science Bulletin 2001年第15期46卷 1281-1285页

作者： he Meiyu XU Jiaxi he xiaoran Tak Wah Dominic Chan Rebecca L.C.Lau Department of Chemistry Peking UniversityBeijing 100871China Beijing Mass Spectrometry Center Beijing 100080China Department of Chemistry The Chinese University of Hong KongShatinN.T.Hong KongChina

The mass spectra of five peptides with biological activities are reported. All mass spectra were recorded using a 4.7-T Fourier transform ion cyclotron resonance mass spectrometer equipped with an external electrospray source. The accurate molecular weights for the five peptides prepared by solid phase synthesis were measured as 1765.9013, 1063.5420, 1092.5254, 820.3804 and 1078.5193, respectively. All the data were obtained with the external calibration. Differences between observed and theoretical monoisotopic molecular weights were in the (0.2-1.0)×10-6 range. The complete primary sequence for the five polypep-tides were determined using the method of in-source electrospray ionization/collision induced dissociation (ESI/CID). All the intact y series ions and b series ions were obtained from various peptides respectively, thus determining the sequences of the five polypeptides. We found that the meas-ured accurate molecular mass of sample 4 was not in agreement with that expected from the planned

关键词： sequence peptide with biological activity Fourier transform ion cyclotron resonance mass spectrometry electrospray collision-induced dissociation.

The Method of Polynomial Particular Solutions for Solving Nonlinear Poisson-Type Equations

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Acta Mechanica Solida Sinica 2024年第1期37卷 155-165页

作者： Zhile Jia Yanhua Cao xiaoran Wu School of Sciences East China Jiaotong UniversityNanchang 330013China

In this paper,the method of polynomial particular solutions is used to solve nonlinear Poisson-type partial differential equations in one,two,and three *** condition number of the coefficient matrix is reduced through the implementation of multiple scale technique,ultimately yielding a stable numerical *** methodological process can be divided into two main parts:first,identifying the corresponding polynomial particular solutions for the linear differential operator terms in the governing equations,and second,employing these polynomial particular solutions as basis function to iteratively solve the remaining nonlinear terms within the governing ***,we investigate the potential improvement in numerical accuracy for equations with singularities in the analytical solution by shifting the computational domain a certain *** experiments are conducted to assess both the accuracy and stability of the proposed method.A comparison of the obtained results with those produced by other numerical methods demonstrates the accuracy,stability,and efficiency of the proposed method in handling nonlinear Poisson-type partial differential equations.

关键词： Nonlinear equation Singularity Polynomial particular solutions Poisson type

A Deep Neural Collaborative Filtering Based Service Recommendation Method with Multi-Source Data for Smart Cloud-Edge Collaboration Applications

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Tsinghua Science and Technology 2024年第3期29卷 897-910页

作者： Wenmin Lin Min Zhu Xinyi Zhou Ruowei Zhang xiaoran Zhao Shigen Shen Lu Sun Alibaba Business School Hangzhou Normal UniversityHangzhou 311121China Blockchain Laboratory of Agricultural Vegetables Weifang University of Science and TechnologyShouguang 262700China School of Computer Science Qufu Normal UniversityRizhao 276827China School of Information Engineering Huzhou UniversityHuzhou 313000China

Service recommendation provides an effective solution to extract valuable information from the huge and ever-increasing volume of big data generated by the large cardinality of user ***,the distributed and rich multi-source big data resources raise challenges to the centralized cloud-based data storage and value mining approaches in terms of economic cost and effective service recommendation *** view of these challenges,we propose a deep neural collaborative filtering based service recommendation method with multi-source data(i.e.,NCF-MS)in this paper,which adopts the cloud-edge collaboration computing paradigm to build recommendation *** specifically,the Stacked Denoising Auto Encoder(SDAE)module is adopted to extract user/service features from auxiliary user profiles and service *** Multiple Layer Perceptron(MLP)module is adopted to integrate the auxiliary user/service features to train the recommendation ***,we evaluate the effectiveness of the NCF-MS method on three public *** experimental results show that our proposed method achieves better performance than existing methods.

关键词： deep neural collaborative filtering multi-source data cloud-edge collaboration application stackeddenoising auto encoder multiple layer perceptron

A Tale of Two“Skewness”:Managerial Epidemic Experience,Probability Weighting and Financial Market Stability

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Social Sciences in China 2024年第1期45卷 157-181页

作者： Gu Leilei Ni xiaoran Peng Yuchao Business School Central University of Finance and Economics School of Economics Xiamen University School of Finance and Belt&Road Finance Institute Central University of Finance and Economics

Under probability weighting,entrepreneurs with skewness preference tend to seek rightskewed and avoid left-skewed *** show that Chinese firms managed by CEOs with professional epidemic experience,i.e.,who previously experienced the outbreak of SARS during their tenure as high level executives,have a lower stock price crash risk measured by the negative skewness of stock prices in subsequent *** particular,those firms intentionally avoid stock price crashes by adopting more conservative strategies in ***,we provide the first evidence on the unintended effect of entrepreneurs'subjective judgments of the probabilities of disease outbreaks on financial market *** have long-term implications for the financial system.

关键词： SARS epidemic experience probability weighting skewness preference stock price crash risk

Joint UAV trajectory and communication design with heterogeneous multi-agent reinforcement learning

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Science China(Information Sciences) 2024年第3期67卷 225-245页

作者： Xuanhan ZHOU Jun XIONG Haitao ZHAO xiaoran LIU Baoquan REN Xiaochen ZHANG Jibo WEI Hao YIN College of Electronic Science and Technology National University of Defense Technology Systems Engineering Institute Academy of Military Sciences PLA

Unmanned aerial vehicles(UAVs) are recognized as effective means for delivering emergency communication services when terrestrial infrastructures are unavailable. This paper investigates a multiUAV-assisted communication system, where we jointly optimize UAVs’ trajectories, user association, and ground users(GUs)’ transmit power to maximize a defined fairness-weighted throughput metric. Owing to the dynamic nature of UAVs, this problem has to be solved in real time. However, the problem’s non-convex and combinatorial attributes pose challenges for conventional optimization-based algorithms, particularly in scenarios without central controllers. To address this issue, we propose a multi-agent deep reinforcement learning(MADRL) approach to provide distributed and online solutions. In contrast to previous MADRLbased methods considering only UAV agents, we model UAVs and GUs as heterogeneous agents sharing a common objective. Specifically, UAVs are tasked with optimizing their trajectories, while GUs are responsible for selecting a UAV for association and determining a transmit power level. To learn policies for these heterogeneous agents, we design a heterogeneous coordinated QMIX(HC-QMIX) algorithm to train local Q-networks in a centralized manner. With these well-trained local Q-networks, UAVs and GUs can make individual decisions based on their local observations. Extensive simulation results demonstrate that the proposed algorithm outperforms state-of-the-art benchmarks in terms of total throughput and system fairness.

关键词： unmanned aerial vehicle (UAV) trajectory design resource allocation multi-agent deep reinforcement learning (MADRL) heterogeneous agents

Divergent responses of growth rate and antioxidative system of ten Bacillus strains to acid stresses

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Soil Ecology Letters 2024年第1期6卷 107-118页

作者： xiaoran Shan Jiayi Chen Jiaen Zhang Ziqiang Liu Shufang Chen Hui Wei Key Laboratory of Agro-Environment in the Tropics of Ministry of Agriculture and Rural Affairs Guangdong Laboratory for Lingnan Modern AgricultureCollege of Natural Resources and EnvironmentSouth China Agricultural UniversityGuangzhou 510642China Guangdong Engineering Research Center for Modern Eco-agriculture and Circular Agriculture South China Agricultural UniversityGuangzhou 510642China

Response of growth rate and antioxidative system of ten Bacillus strains to acid stresses was *** acid treatment significantly decreased the growth rate of the *** stresses increased the GPX activity and GSSG content of the tested *** changes occurred in ROS and antioxidative system(SOD,CAT,GR,MDA and GSH).Environmental changes including soil acidification exert obvi-ous stresses on soil ecosystems and influence soil *** this study,ten microbial strains were incubated under different acid treatments to investigate responses of microbial growth and antioxidative system to acid *** the strains belong to Bacillus genus,but exhibit distinct ecological *** observed that these microbial strains had obviously different pH tolerance threshold,in spite of the close phylogenetic classification among *** stresses exerted significant effects on microbial antiox-idative system,including superoxide dismutase(SOD),cata-lase(CAT)and glutathione transferring enzymes(GPX and GR)and reactants(GSH and GSSH),but the effects were strain ***,we found acid stress effects on total variances of the investigated microbial antioxidative system along the first two principal components(PCs).Activities of CAT and SOD contributed substantially to PC1 that reflected obvious acid effects on NC7 and ZC4,and closely related to intracellular malondialdehyde *** GSSG activities and GSH/GSSG contributed greatly to PC2 that unveiled acid stress effects on most of the microbial *** results highlight substantially heterogeneous responses of microbial strains to acid stress and support that phylogenetic closeness does not imply functional similarity of soil microorganisms under environmental changes.

关键词： soil acidification microbial strain acid tolerance capacity microbial growth oxidative stress antioxidative system

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青霉素发酵过程的模型仿真与补料优化

化工学报 2012年第9期63卷 2831-2835页

作者：贺晓冉陈宸金光石熊智华清华大学自动化系北京100084 金策工业综合大学自动化系

补料分批式青霉素发酵的机理模型已得到深入研究,但是模型往往难以用于补料的优化和批次内的控制。为了对模型进行优化控制,针对Birol等提出的青霉素发酵非结构动力学模型,合理调整了温度和pH变化的影响,得到了青霉素发酵过程的简化机... 详细信息

补料分批式青霉素发酵的机理模型已得到深入研究,但是模型往往难以用于补料的优化和批次内的控制。为了对模型进行优化控制,针对Birol等提出的青霉素发酵非结构动力学模型,合理调整了温度和pH变化的影响,得到了青霉素发酵过程的简化机理模型。反应基质的补料是青霉素优化控制的关键,选择对补料速率进行优化来提高青霉素的产量。由于机理模型具有非线性和约束条件,采用序贯二次规划算法来进行求解,其中将补料轨线进行分段处理提高了优化效率。优化计算结果表明改进的补料过程可以提高青霉素的浓度和产量。

关键词：青霉素发酵机理模型仿真补料优化

Pressure stimulated current in progressive failure process of combined coal-rock under uniaxial compression:Response and mechanism

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International Journal of Mining Science and Technology 2024年第2期34卷 227-243页

作者： Tiancheng Shan Zhonghui Li Xin Zhang Haishan Jia xiaoran Wang Enyuan Wang Yue Niu Dong Chen Weichen Sun Dongming Wang State Key Laboratory of Coal Mine Disaster Prevention and Control China University of Mining and TechnologyXuzhou 221116China National Engineering Research Center for Coal Gas Control China University of Mining and TechnologyXuzhou 221116China School of Safety Engineering China University of Mining and TechnologyXuzhou 221116China State Key Laboratory for Fine Exploration and Intelligent Development of Coal Resources China University of Mining and TechnologyXuzhou 221116China State Key Laboratory of Intelligent Construction and healthy Operation and Maintenance of Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China

Effective monitoring of the structural health of combined coal-rock under complex geological conditions by pressure stimulated currents(PSCs)has great potential for the understanding of dynamic disasters in underground *** reveal the effect of this way,the uniaxial compression experiments with PSC monitoring were conducted on three types of coal-rock combination samples with different strength *** mechanism explanation of PSCs are investigated by resistivity test,atomic force microscopy(AFM)and computed tomography(CT)methods,and a PSC flow model based on progressive failure process is *** influence of strength combinations on PSCs in the progressive failure process are *** results show the PSC responses between rock part,coal part and the two components are different,which are affected by multi-scale fracture characteristics and electrical *** the rock strength decreases,the progressive failure process changes obviously with the influence range of interface constraint effect decreasing,resulting in the different responses of PSC strength and direction in different parts to fracture *** PSC flow model is initially validated by the relationship between the accumulated charges of different *** results are expected to provide a new reference and method for mining design and roadway quality assessment.

关键词： Combined coal-rock Pressure stimulated current Progressive failure process Mechanism Flow model

Observation of the failure mechanism in Ag_(10)Ge_(15)Te_(75)-based memristor induced by ion transport

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Nano Research 2024年第9期17卷 8431-8437页

作者： Yuwei Xiong Kuibo Yin Weiwei Sun Jingcang Li Shangyang Shang Lei Xin Qiyun Wu xiaoran Gong Yidong Xia Litao Sun SEU-FEI Nano-Pico Center Key Laboratory of MEMS of Ministry of EducationSoutheast UniversityNanjing 210096China College of Engineering and Applied Sciences Nanjing UniversityNanjing 210093China

The solid-electrolyte-based memristors have attracted tremendous attention for the next-generation nonvolatile memory for both logic and neuromorphic ***,they encounter variability performance challenges which originated from the random ionic transport and conductive filaments ***,the electrochemical metallized mechanism associated with ion transport has been ***,the failure mechanism caused by ion transport during cycles is rarely ***,the five stages of failure in the Ag/Ag_(10)Ge_(15)Te_(75)/W memristor are elucidated through ex-situ current-voltage measurements combined with in-situ transmission electron microscopy *** investigation reveals that the migration and enrichment of Ag ions result in the precipitation of Ag_(2)*** formation of Ag_(2)Te hinders the device's ability to maintain its bipolar characteristics and also decreases the resistance value of the high resistance state,thereby reducing the device's switching *** promising results provide important guidance for the future design of structures and the manipulation of ion transport for high-performance memristors.

关键词： Ag10Ge15Te75 in-situ transmission electron microscopy(TEM) failure mechanism