检索结果-南通市图书馆

Characteristics of force chains in frictional interface during abrasive flow machining based on discrete element method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Manufacturing 2018年第4期6卷 355-375页

作者： tian-xun Xiu Wei Wang Kun Liu Zhi-Yong Wang Dao-Zhu Wei School of Mechanical Engineering. Hefei University of Technology Hefei 230009 People's Republic of China Changzhou Borui Power Automation Equipment Co. Ltd Changzhou 213025 Jiangsu People's Republic of China

Abrading is a very important sub-technology of the surface treatment tech no logy with vast applications in the industry. This study aims at analyzing the inherent laws of friction systems during abrading. In particle flow code modeling, the abrading process can be simplified to the movement of particles in a parallel-plate shear friction system. In this study, the PFC2D software is used to construct the particle flow friction system with the set of parallel plates and the model parameters according to the abrading processing equipment and processing materials, control the simulation of a single variable, and compare the output data to estimate the impact of change of parameters on the force chain. The simulation results show that the shear dilatancy can be divided into three stages: plastic strain, macroscopic failure, and granular recombination stages. The distribution and load rates of the weak force chains depend on the load, velocity, friction coefficient between granules, granular diameter, and number of granular layers. The number of granular layers and the load increase cause the direction of the force chain to be oriented with the vertical direction, and the force chains move toward the horizontal direction as the velocity increases. The increase in load does not cause the shear dilatancy stage to occur;the velocity, friction coefficient between granules, and granular diameter increase cause the shear dilatancy to occur gradually.

关键词： Abrasion Force Machining

Diastereoselective Michael Addition of (4'S)-Ethyl-3-(2',2'-Dimethyl-1',3'- dioxolan-4'-yl) acrylate with Furyl Lithium

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2001年第5期12卷 403-406页

作者： Dong Mei HAN xun tian JIANG Jian Hong CHEN Bin WANG Dong Lu BAI Shanghai Institute of Meteria Medica Shanghai Institutes for Biological SciencesChinese Academy of SciencesShanghai 200031

Michael addition of the chiral alpha,beta -unsaturated ester 2 with furyl lithium proceeded in syn manner with excellent diastereoselectivity. The diastereoselectivity was not affected by the configuration of the doub... 详细信息

关键词： Michael addition configuration determination syn addition.

Construction of the Core of Pseudolaric Acid A and Mechanistic Studies on Intramolecular [4+3] Cycloaddition

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2001年第2期12卷 113-116页

作者： xun tian JIANG Li Gong OU Dong Mei HAN Yu Feng ZHAI Dong Lu BAI Shanghai Institute of Materia Medica Chinese Academy of Sciences294 Taiyuan RoadShanghai200031

This paper describes the construction of hemiacetal 2, the core of pseudolaric acid A via oxidative cleavage of acetonide 6 or 7 and enolization-hemiacetalization of aldehyde 8. A plausible general mechanism for thc i... 详细信息

关键词： pseudolaric acid A 5, 7-membered fused ring hemiacetal intramolecular [4+3] cycloaddition mechanism

Allograft rejection-related gene expression in the endothelial cells of renal transplantation recipients after cytomegalovirus infection

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第11期10卷 820-828页

作者： Yang LI Hang YAN Wu-jun XUE Pu-xun tian Xiao-ming DING Xiao-ming PAN Xin-shun FENG Xiao-hui tian He-li XIANG Jun HOU Department of Renal Transplantation Center of Nephropathy the First Affiliated Hospital School of Medicine Xi 'an Jiaotong University Xi 'an 710061 China The two authors contributed equally to this work

Objective： To explore the effects of cytomegalovirus （CMV） infection on rejection-related gene expression in the endothelial cells of renal transplantation recipients. Methods： Endothelial cells （ECs） were cultured and stimulated by a variety of factors： A, normal control group; B, inactivated human cytomegalovirus （HCMV） infection group; C, HCMV infection group; D, HCMV supematant infection group; and E, ganciclovir HCMV group. Expression of intercellular adhesion molecule-1 （ICAM-1） and major histocompability complex （MHC） class I and class II antigens was detected by flow cytometry （FCM） and immuno- histochemistry. Results： We found characteristic CMV-infected ECs in this study. There were no significant differences among groups A, B and D （P〉0.05）. Although the expression levels of ICAM-1 were not significantly different between groups C and E （P〉0.05）, the ICAM-1 expression in these two groups was significantly higher than that in group A （P〈0.05）. ICAM-1 expression was detected in groups C and E, while there was no expression in groups A, B and D. Furthermore, there was no significant difference of ICAM-1 mRNA expression between groups C and E （P〉0.05）. Human leucocyte antigen （HLA）-ABC expression was detected in all the groups, while HLA-DR expression was only detected in groups C and E. There were no significant dif- ferences of HLA-ABC and HLA-DR expression among groups A, B and D （P〉0.05）. However, the HLA-ABC and HLA-DR expression levels in groups C and D were higher than those of the remaining groups previously reported （P〈0.05）. Meanwhile, the HLA-ABC and HLA-DR expression levels in group E were lower than those of group C （P〈0.05）. Conclusion： CMV could up-regulate the expression levels of ICAM-1 and MHC antigens, which was closely related to allograft rejection.

关键词： Renal transplantation Cytomegalovirus (CMV) Rejection Intercellular adhesion molecule-1 (ICAM-1) Major histocompability complex (MHC)

Effect of small intestinal submucosa on islet recovery and function in vitro culture

在线全文

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2005年第4期4卷 524-529页

作者： Xiao-Hui tian Wu-Jun Xue Xin-Lu Pang Yan Teng Pu-xun tian Xin-Shun Feng Department of Renal Transplantation First Affiliated Hospital College of Medicine Xi'an Jiaotong University Xi'an 710061 China.

BACKGROUND: The ability to maintain isolated human islet preparation in tissue culture has recently been adopted by most islet transplant centers to improve the safety and practicality of islet transplantation. However, maintaining islet viability and recovery remains a challenge in clinical setting. Extracellular matrix (ECM) is one of the most important components of islet microenvironment. The reconstruction of the cell-matrix relationship seems to be effective in improving the loss of differentiated islet structure and function. Small intestinal submucosa ( SIS ) , a naturally occurring ECM, has been investigated to be able to promote wound healing, tissue remodeling, and cell growth. The purpose of this study was to evaluate the recovery and function of isolated rat pancreatic islets after in vitro culture with SIS. METHODS: Pancreatic islets were isolated from Wistar rats by using standard surgical procurement followed by intra-ductal collagenase distension, mechanical dissociation, and EuroFicoll purification. Groups of purified islets were cultured in plates which were coated with multilayer SIS (SIS-treated group) or without ( standard cultured group) for 7 days and 14 days in standard islet culture conditions of RP-MI 1640 tissue culture media in humidified atmosphere containing 95% air and 5% CO2 at 37 ℃. The mean recovery of islets after the culture period was determined by sizing duplicate counts of a known volume and their viability was assessed by static incubation with low glucose (2.7 mmol) , high glucose (16.7 mmol) and high glucose solution supplemented with 50 μm 3-isobutyl-1-methylxanthine (IB-MX) solution. RESULTS: After 7 days and 14 days of in vitro tissue culture, the SIS-treated group showed a significantly higher recovery compared with those cultured under standard conditions. The recovery in the SIS-treated group was about two times of the control group cultured in standard conditions after 14 days culture. In the SIS-treated group, there

关键词： islet culture islet recovery islet function small intestinal submucosa

Genome editing for the treatment of tumorigenic viral infectionsand virus-related carcinomas

在线全文

学校读者我要写书评

暂无评论

Frontiers of Medicine 2018年第5期12卷 497-508页

作者： Lan Yu xun tian Chun Gao Ping Wu Liming Wang Bei Feng Xiaomin Li Hui Wang Ding Ma Zheng Hu Cancer Biology Research Center (Key Laboratory of the Ministry of Education) Tongji Hospital Tong/i Medical College HuazhongUniversity of Science and Technology Wuhan 430030 China Department of Obstetrics and Gynecology Tongji Hospital Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 China Department of Gynecological Oncology First AffiliatedHospital of Sun Yat-sen University Guangzhou 510080 China Department of Gynecology and Obstetrics First Affiliated Hospital ofGuangzhou Medical University Guangzhou 510120 China

Viral infections cause at least 10%-15% of all human carcinomas. Over the last century, the elucidation of viral oncogenic roles in many cancer types has provided fundamental knowledge on carcinogenetic mechanisms and established a basis for the early intervention of virus-related cancers. Meanwhile, rapidly evolving genome-editing techniques targeting viral DNA/RNA have emerged as novel therapeutic strategies for treating virus-related carcinogenesis and have begun showing promising results. This review discusses the recent advances of genome-editing tools for treating tumorigenic viruses and their corresponding cancers, the challenges that must be overcome before clinically applying such genome-editing technologies, and more importantly, the potential solutions to these challenges.

关键词： delivery method genome-editing tools off-target effect tumorigenic virus virus-related carcinoma

VIS Atlas:A Database of Virus Integration Sites in Human Genome from NGS Data to Explore Integration Patterns

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 2023年第2期21卷 300-310页

作者： Ye Chen Yuyan Wang Ping Zhou Hao Huang Rui Li Zhen Zeng Zifeng Cui Rui tian Zhuang Jin Jiashuo Liu Zhaoyue Huang Lifang Li Zheying Huang xun tian Meiying Yu Zheng Hu Department of Obstetrics and Gynecology the First Affiliated HospitalSun Yat-sen UniversityGuangzhou 510000China Department of Obstetrics and Gynecology Dongguan Maternal and Child Health Care HospitalDongguan 523000China Office of Scientific Research&Development Sun Yat-sen UniversityGuangzhou 510000China Department of Obstetrics and Gynecology Academician Expert WorkstationThe Central Hospital of WuhanTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430000China Center for Translational Medicine the First Affiliated HospitalSun Yat-sen UniversityGuangzhou 510000China Department of Pathology the Central Hospital of Enshi Tujia and Miao Autonomous PrefectureEnshi 445000China Department of Obstetrics and Gynecology Zhongnan Hospital of Wuhan UniversityWuhan 430062China

Integration of oncogenic DNA viruses into the human genome is a key step in most virusinduced ***,we constructed a virus integration site(VIS)Atlas database,an extensive collection of integration breakpoints for three most prevalent oncoviruses,human papillomavirus,hepatitis B virus,and Epstein-Barr virus based on the next-generation sequencing(NGS)data,literature,and experimental *** are 63,179 breakpoints and 47,411 junctional sequences with full annotations deposited in the VIS Atlas database,comprising 47 virus genotypes and 17 disease *** VIS Atlas database provides(1)a genome browser for NGS breakpoint quality check,visualization of VISs,and the local genomic context;(2)a novel platform to discover integration patterns;and(3)a statistics interface for a comprehensive investigation of genotypespecific integration *** collected in the VIS Atlas aid to provide insights into virus pathogenic mechanisms and the development of novel antitumor drugs.

关键词： DNA virus Virus integration site Next-generation sequencing Integration pattern Virus genotype

Puncturing Period on the Performance of Punctured Turbo Codes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural Sciences 2002年第3期7卷 319-322页

作者： Xu Heng\|ping, Pan Sheng, Zhao xun, Rong Meng\|tian Department of Electronic Engineering, Shanghai Jiaotong University, Shanghai 200030, Shanghai, China Shanghai Jiaotong University Department of Electronic Engineering Shanghai Shanghai China (GRID:grid.16821.3c) (ISNI:***)

Puncturing is the predominant strategy to construct high code rate turbo codes. Puncturing period is a crucial parameter influencing the performance of punctured turbo codes (PTC). Here we developed a new puncturing scheme of turbo codes, with which the puncturing period on the performance of PTC is studied. Consequently, suggestions on selecting the puncturing period are proposed.

关键词： Key words puncturing period puncturing table AWGN turbo codes

Magnetic cell sorting and flow cytometry sorting methods for the isolation and function analysis of mouse CD^4+ CD25^+ Treg cells

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第12期10卷 928-932页

作者： Hang YAN Chen-guang DING Pu-xun tian Guan-qun GE Zhan-kui JIN Li-ning JIA Xiao-ming DING Xiao-ming PAN Wu-jun XUE Department of Renal Transplantation Center of Nephropathy the First Affiliated Hospital Medicine College Xi'an Jiaotong University Xi'an 710061 China

Objective: In this paper we compared the two methods of cell sorting (magnetic cell sorting and flow cytometry sorting) for the isolation and function analysis of mouse CD4+ CD25+ regulatory T (Treg) cells, in order to inform further studies in Treg cell function. Methods: We separately used magnetic cell sorting and flow cytometry sorting to identify CD4+ CD25+ Treg cells. After magnetic cell separation, we further used flow cytometry to analyze the purity of CD4+ CD25+ Treg cells, trypan blue staining to detect cell viability, and propidium iodide (PI) staining to assess the cell viability. We detected the immune inhibition of CD4+ CD25+ Treg cells in the in vitro proliferation experiments. Results: The results showed that compared to flow cytometry sorting, magnetic cell sorting took more time and effort, but fewer live cells were obtained than with flow cytometry sorting. The CD4+ CD25+ Treg cells, however, obtained with both methods have similar immunosuppressive capacities. Conclusion: The result suggests that both methods can be used in isolating CD4+ CD25+ Treg cells, and one can select the best method according to specific needs and availability of the methodologies.

关键词： CD4+ CD25+ Treg cells Flow cytometry sorting Magnetic cell sorting