检索结果-南通市图书馆

Shamanskii-Like Levenberg-Marquardt Method with a New Line Search for Systems of Nonlinear Equations

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2020年第5期33卷 1694-1707页

作者： chen Liang MA Yanfang School of Mathematical Sciences Huaibei Normal UniversityHuaibei 235000China School of Compuler Science and Technology Huaibei Normal UniversityHuaibei 235000China

To save the calculations of Jacobian,a multi-step Levenberg-Marquardt method named Shamanskii-like LM method for systems of nonlinear equations was proposed by Fa.Its convergence properties have been proved by using a trust region technique under the local error bound condition.However,the authors wonder whether the similar convergence properties are still true with standard line searches since the direction may not be a descent direction.For this purpose,the authors present a new nonmonotone m-th order Armijo type line search to guarantee the global convergence.Under the same condition as trust region case,the convergence rate also has been shown to be m+1 by using this line search technique.Numerical experiments show the new algorithm can save much running time for the large scale problems,so it is efficient and promising.

关键词： Armijo line search Levenberg-Marquardt method local error bound condition systems of nonlinear equations unconstrained optimization

Reprogramming the tumor immune microenvironment via nanomaterial-mediated dynamic therapy

在线全文

学校读者我要写书评

暂无评论

Nano Research 2023年第12期16卷 13100-13112页

作者： Wangbo Jiao Yao Feng chen Liang Qiaoyi Lu Haiming Fan Xing-Jie liang Xiaoli Liu Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education College of Chemistry and Materials ScienceNorthwest UniversityXi’an 710069China Laboratory of Controllable Nanopharmaceuticals Chinese Academy of Sciences(CAS)Center for Excellence in Nanoscience and CAS Key Laboratory for Biomedical Effects of Nanomaterials and NanosafetyNational Center for Nanoscience and TechnologyBeijing 100190China Institute of Regenerative and Reconstructive Medicine Med-X InstituteFirst Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710049China

Our improved knowledge of tumor immunology laid a solid foundation for the clinical use of tumor immunotherapies such as immune checkpoint blockers,and the efficacy of these drugs increased our confidence that immunomodulation was a viable way of treating cancer.The basis of immunotherapy is to break the immune escape of the tumor and resolve the immune suppressive microenvironment of tumors.Nanomaterial-mediated dynamic therapy(NDT)is an emerging immuno-regulatable type for tumor therapy,whose effects are mediated by increased cellular levels of reactive oxygen species(ROS).ROS is a potent trigger of immunogenic cell death,and this process initiates antitumor immunity.Nanomaterials for use in NDT can be engineered to interact with almost all cell types in the tumor microenvironment to remodel this environment.In this review,we systematically examined the effects of NDT on four major cell types in the tumor microenvironment,namely tumor cells,lymphocytes,myeloid cells,and tumor stromal cells.We believe that this review will improve researchers’understanding of the anti-tumor immunity triggered by NDT,and provide ideas and inspiration for how optimally designed NDT schemes can be used to target the cells in the tumor microenvironment.

关键词： tumor immunotherapy tumor immune microenvironment nanomaterials reactive oxygen species immune cells

Accelerated prediction of Cu-based single-atom alloy catalysts for CO_(2) reduction by machine learning

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Green Energy & Environment 2023年第3期8卷 820-830页

作者： Dashuai Wang Runfeng Cao Shaogang Hao chen Liang Guangyong chen Pengfei chen Yang Li Xiaolong Zou Shenzhen Geim Graphene Center Tsinghua-Berkeley Shenzhen Institute&Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen518055China Tencent Shenzhen518054China Shenzhen Key Laboratory of Virtual Reality and Human Interaction Technology Shenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhen518055China Department of Mechanical and Automation Engineering The Chinese University of Hong KongHong Kong999077China Tsinghua-Berkeley Shenzhen Institute Tsinghua UniversityShenzhen518055China

Various strategies,including controls of morphology,oxidation state,defect,and doping,have been developed to improve the performance of Cu-based catalysts for CO_(2) reduction reaction(CO_(2)RR),generating a large amount of data.However,a unified understanding of underlying mechanism for further optimization is still lacking.In this work,combining first-principles calculations and machine learning(ML)techniques,we elucidate critical factors influencing the catalytic properties,taking Cu-based single atom alloys(SAAs)as examples.Our method relies on high-throughput calculations of 2669 CO adsorption configurations on 43 types of Cu-based SAAs with various surfaces.Extensive ML analyses reveal that low generalized coordination numbers and valence electron number are key features to determine catalytic performance.Applying our ML model with cross-group learning scheme,we demonstrate the model generalizes well between Cu-based SAAs with different alloying elements.Further,electronic structure calculations suggest surface negative center could enhance CO adsorption by back donating electrons to antibonding orbitals of CO.Finally,several SAAs,including PCu,AgCu,GaCu,ZnCu,SnCu,GeCu,InCu,and SiCu,are identified as promising CO_(2)RR catalysts.Our work provides a paradigm for the rational design and fast screening of SAAs for various electrocatalytic reactions.

关键词： Cu-based single-atom alloy CO adsorption Machine learning First principles CO_(2)reduction reaction

Big Theta Equals Small Theta Generically

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2024年第3期40卷 717-730页

作者： Rui chen Jia liang ZOU Institute for Advanced Study in Mathmatics Zhejiang UniversityHangzhou 310058P.R.China Department of Mathematics University of Michigan530 Church StAnn ArborMI 48109USA

In this paper we consider the theta correspondence over a non-Archimedean local field.Using the homological method and the theory of derivatives,we show that under a mild condition the bigtheta lift is irreducible.

关键词： Theta correspondence derivatives

Urbanization of county in China:Spatial patterns and influencing factors

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2022年第7期32卷 1241-1260页

作者： ZHANG Hua chen Mingxing liang chen Beijing Key Laboratory of Environmental Remote Sensing and Digital Cities Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Key Laboratory of Regional Sustainable Development Modeling Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

This paper uses the fifth and sixth census data and 2018 demographic statistics to analyze the spatiotemporal evolution of the urbanization of county in China and the factors that influence the evolution.The paper reveals that the urbanization level of counties is a weak area in China’s overall urbanization.During the period from 2000 to 2010,the spatial patterns of the urbanization level of counties remained stable.Counties with high-level urbanization were concentrated in the coastal areas of the eastern region,while counties that experienced rapid urbanization were mainly located in the central and western regions.Regression analyses indicate that harsh natural endowments that constrain economic development are the most important factors that hinder the urbanization of county;these factors include marginalized locations far away from center cities,high altitudes,and a population with a low education level.This paper also compares two theoretical modes of new-type urbanization,nearby urbanization and remote urbanization,and argues that the new-type urbanization of county is the main form of nearby urbanization and provides an example of urbanization for developing countries worldwide.

关键词： new-type urbanization urbanization of county nearby urbanization spatial patterns influencing factors

AFM probe for measuring~10^(−5)ultra-low friction coefficient:Design and application

在线全文

学校读者我要写书评

暂无评论

Friction 2024年第1期12卷 64-73页

作者： Yushan chen liang JIANG Linmao QIAN Tribology Research Institute State Key Laboratory of Traction PowerSouthwest Jiaotong UniversityChengdu 610031China

Superlubricity provides a novel approach to addressing friction and wear issues in mechanical systems.However,little is known regarding improving the atomic force microscope(AFM)friction coefficient measurement resolution.Accordingly,this study established the theoretical formula for the AFM friction coefficient measurement and deduced the measurement resolution.Then,the formula was applied to the AFM probe with a rectangular cross-section cantilever.The measurement resolution is associated with the dimensional properties of the AFM probe,the mechanical properties of the cantilever material,the properties of the position-sensitive detector(PSD),and probably the anti-vibration performance of the AFM.It is feasible to make the cantilever as short as possible and the tip as high as possible to improve the measurement resolution.An AFM probe for measuring an ultra-low friction coefficient was designed and fabricated.The cantilever’s length,width,and thickness are 50,35,and 0.6μm,respectively.The tip height is 23μm.The measurement resolution can reach 7.1×10^(−6) under the maximum normal force.Moreover,the AFM probe was applied to measure the superlubricity between graphene layers.The friction coefficient is 0.00139 under 853.08 nN.This work provides a promising method for measuring a~10^(−5) friction coefficient of superlubricity.

关键词： atomic force microscope(AFM) superlubricity friction coefficientμ probe

scEMAIL: Universal and Source-free Annotation Method for scRNA-seq Data with Novel Cell-type Perception

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Genomics, Proteomics & Bioinformatics 2022年第5期20卷 939-958页

作者： Hui Wan liang chen Minghua Deng School of Mathematical Sciences Peking UniversityBeijing 100871China Huawei Technologies Co. Ltd.Beijing 100080China Center for Statistical Science Peking UniversityBeijing 100871China Center for Quantitative Biology Peking UniversityBeijing 100871China

Current cell-type annotation tools for single-cell RNA sequencing(sc RNA-seq)data mainly utilize well-annotated source data to help identify cell types in target data.However,on account of privacy preservation,their requirements for raw source data may not always be satisfied.In this case,achieving feature alignment between source and target data explicitly is impossible.Additionally,these methods are barely able to discover the presence of novel cell types.A subjective threshold is often selected by users to detect novel cells.We propose a universal annotation framework for sc RNA-seq data called sc EMAIL,which automatically detects novel cell types without accessing source data during adaptation.For new cell-type identification,a novel cell-type perception module is designed with three steps.First,an expert ensemble system measures uncertainty of each cell from three complementary aspects.Second,based on this measurement,bimodality tests are applied to detect the presence of new cell types.Third,once assured of their presence,an adaptive threshold via manifold mixup partitions target cells into‘‘known”and‘‘unknown”groups.Model adaptation is then conducted to alleviate the batch effect.We gather multi-order neighborhood messages globally and impose local affinity regularizations on‘‘known”cells.These constraints mitigate wrong classifications of the source model via reliable self-supervised information of neighbors.sc EMAIL is accurate and robust under various scenarios in both simulation and real data.It is also flexible to be applied to challenging single-cell ATAC-seq data without loss of superiority.The source code of sc EMAIL can be accessed at https://***/aster-ww/sc EMAIL and https://***/biocode/tools/BT007335/releases/v1.0.

关键词： Cell-type annotation Transfer learning Privacy preservation Single-cell RNA sequencing Gene expression

Downregulation of Astrocyte Elevated Gene-1 Expression Combined with All-Trans Retinoic Acid Inhibits Development of Vasculogenic Mimicry and Angiogenesis in Glioma

在线全文

学校读者我要写书评

暂无评论

Current Medical Science 2022年第2期42卷 397-406页

作者： chen Liang Ling YANG Shi-wen GUO Rui-chun LI Department of Neurosurgery First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an710061China Department of Aeromedical Physical Examination Xi’an Civil Aviation HospitalXi’an710082China

Objective This study aimed to investigate the effects of downregulating astrocyte elevated gene-1(AEG-1)expression combined with all-trans retinoic acid(ATRA)on vasculogenic mimicry(VM)formation and angiogenesis in glioma.Methods U87 glioma cells were transfected with AEG-1 shRNA lentiviral vectors(U87-siAEG-1)and incubated in a medium containing 20µmol/L ATRA.Matrigel-based tube formation assay was performed to evaluate VM formation,and the cell counting kit-8(CCK-8)assay was used to analyze the proliferation of glioma cells in vitro.Reverse transcription-quantitative polymerase chain reaction and Western blot analysis were used to investigate the mRNA and protein expression of related genes,respectively.Glioma xenograft models were generated via subcutaneous implantation of glioma cells in nude mice.Tumor-bearing mice received an intraperitoneal injection of ATRA(10 mg/kg per day).Immunohistochemistry was used to evaluate the expression of related genes and the microvessel density(MVD)in glioma xenograft models.CD34/periodic acid-Schiff double staining was performed to detect VM channels in vivo.The volume and weight of tumors were measured,and a tumor growth curve was drawn to evaluate tumor growth.Results A combination of ATRA intervention and downregulation of AEG-1 expression significantly inhibited the proliferation of glioma cells in vitro and glioma VM formation in vitro and in vivo.It also significantly decreased MVD and inhibited tumor growth.Further,the expression levels of matrix metalloproteinase(MMP)-2,MMP-9,vascular endothelial-cadherin(VE-cadherin),and vascular endothelial growth factor(VEGF)in glioma significantly decreased in vivo and in vivo.Conclusion Hence,a combinatorial approach might be effective in treating glioma through regulating MMP-2,MMP-9,VEGF,and VE-cadherin expression.

关键词： astrocyte elevated gene-1 glioma all-trans retinoic acid vasculogenic mimicry angiogenesis

Circular RNAs remain peculiarly unclear in biogenesis and function

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2015年第6期58卷 616-618页

作者： chen Liang SHAN Ge School of Life Sciences & CAS Key Laboratory of Brain Function and Disease University of Science and Technology of China

The known complexity of eukaryotic transcriptomes has been greatly expanded due to the identification of a large family of circular RNAs in recent years[1?3].As a special form of RNA compared to the"common"linear form,these molecules were first described in 1976,when it was discovered that several plant viroids were single-stranded and covalently closed circular RNAs[4].In a broad sense。

关键词： RNA 生物合成圆形线性形式复杂性类病毒家族转录