检索结果-南通市图书馆

Preliminarily Investigating the Polymorphism of Self-organized Actin Filament in Vitro by atomic force microscope

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

Acta Biochimica et Biophysica Sinica 2004年第9期36卷 637-643页

作者： Jun ZHANG1,2, Yuan-Liang WANG1*, Xin-Yong Chen3, Chuang-Long HE1, Chao CHENG1, and Yang CAO1 1Key Lab of Biomechanics & Tissue Engineering, Chongqing University, Chongqing 400044, China Biology Department, Chongqing University of Medicine Sciences, Congqing 400016, China 3Laboratory of Biophysics and Surface Analysis, University of Nottingham, Nottingham NG7 2RD, United Kingdom Key Lab of Biomechanics & Tissue Engineering Chongqing UniversityChongqing 400044 China Biology Department Chongqing University of Medicine SciencesCongqing 400016 China Laboratory of Biophysics and Surface Analysis University of NottinghamNottingham NG7 2RD United Kingdom

With the atomic force microscope (AFM), we preliminarily investigated the large-scale structure of actin filaments formed in low concentration protein solution (5 μg/ml) via self-organization without the presence of any F-actin dynamic interfering factors (such as phalloidin)in vitro. It was found that the G-actin could be polymerized into ordered filamentous structures with different diameter from the slimmest filament of single F-actin to giant filament in tree-like branched aggregates. The observed polymerized actin filaments, to which our most intense attention was attracted, was discretely distributed and showed obvious polymorphism distinctly different from those in the presence of phalloidin or actin binding proteins (fimbrin, gelsolin, etc.) in previous experiments. Latter structures were mainly composed of single F-actin and/or multifilaments clearly consisting of several single F-actin. The experimental results clearly demonstrated that non-interference with the F-actin intrinsic dynamics in self-organizing could lead to the polymorphism of actin filamentous structures, and further analysis implied that the disturbance of normal F-actin dynamics by many factors could prevent the emergence of structural polymorphism, more often than not, give rise to formation of specific structures instead and different interference would bring about various particular structures under certain conditions.

关键词： actin self-organization filamentous structure polymorphism atomic force microscope

Surface Electromechanical Coupling on DLC Film with Conductive atomic force microscope

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Plasma Science and Technology 2004年第3期6卷 2342-2345页

作者：朱守星丁建宁范真李长生蔡兰杨继昌 Schcool of Mechanical Engineering Donghua University Shanghai 200051 China 2 Micro/Nano Science and Technology Research Center JiangSu University Zhen-jiang 212013 China

Diamond-like carbon (DLC) film composed of microscopically insulation but microscopically a mixture of conducting (sp2) and insulating (sp3) phases was discussed on the local modification with a conductive atomic force microscope (C-APM). Especially, a topographic change was observed when a direct current (DC) bias-voltage was applied to the DLC film. Experimental results show that a nanoscale pit on DLC surface was formed when applying a positive 25 V on DLC film. According to the interacting force between CoCr-coated microelectronic scanning probe (MESP) tip and DLC surface, as well as the Sondheimer oscillation theory, the 'scalewing effect' of the pit was explained. Electromechanical coupling on DLC film suggested that the depth of pits increased with an increase of load applied to surface when the cantilever-deflected signal was less than a certain threshold voltage.

关键词： atomic force microscope diamond-like carbon surface modification electromechanical coupling

Edge Effects and Coupling Effects in atomic force microscope Images

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2004年第B10期19卷 63-65页

作者：张向军 Tsinghua University

The AFM images were obtained by an atomic force microscope (AFM) and transformed from the deformation of AFM micro cantilever probe. However, due to the surface topography and surface forces applied on the AFM tip of sample, the deformation of AFM probe results in obvious edge effects and coupling effects in the AFM images.The deformation of AFM probe was analyzed,the mechanism of the edge effects and the coupling effects was investigated, and their results in the AFM images were studied. It is demonstrated by the theoretical analysis and AFM experiments that the edge effects make lateral force images more clear than the topography images,also make extraction of frictional force from lateral force images more complex and difficult. While the coupling effects make the comparison between topography images and lateral force images more advantage to acquire precise topography information by AFM.

关键词： atomic force microscope micro-scale topography edge effects coupling effects

Competitive Adsorption between Bovine Serum Albumin and Collagen Observed by atomic force microscope

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2004年第12期15卷 1465-1468页

作者： Yong YU Pei Qing YING Gang JIN National Microgravity Lab,Institute of Mechanics,Chinese Academy of Sciences, Beijing 100080 National Microgravity Lab. Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

atomic force microscopy (AFM) was used to study the competitive adsorption betweenbovine serum albumin (BSA) and type Ⅰ collagen on hydrophilic and hydrophobic silicon wafers.BSA showed a grain shape and the type Ⅰ collagen displayed fibril-like molecules with relativelyhomogeneous height and width, characterized with clear twisting (helical formation). These AFMimages illustrated that quite a lot of type Ⅰ collagen appeared in the adsorption layer on hydrophilicsurface in a competitive adsorption state, but the adsorption of BSA was more preponderant than thatof type Ⅰ collagen on hydrophobic silicon wafer surface. The experiments showed that theinfluence of BSA on type Ⅰ collagen adsorption on hydrophilic surface was less than that onhydrophobic surface.

关键词： atomic force microscope protein competitive adsorption collagen bovine serum albumin.

atomic force microscope VISUALIZED ETHIDIUM BROMIDE-INDUCED CHROMOSOMAL DAMAGE

在线全文

学校读者我要写书评

暂无评论

ATOMIC FORCE MICROSCOPE VISUALIZED ETHIDIUM BROMIDE-INDUCED ...

Nonlinear control techniques for an atomic force microscope system

Asia Conference on Nanoscience and Nanotechnology Abstracts Book

作者： YANDZHE WU, JIYB CAI, KBYU YUN, YONO CHEN, LONGQIU CHEN, CHENXI WANG Chemistry Department, Jinan University Guangzhou 510632, China Biomedical Engineering Department, Jinan University GuangZhou 510632, China College of Science and Engineering, Jinan University GuangZhou 510632, China

Ethidium Bromide (EB), a heterocyclic organic substance, can insert between base pairs, resulting in increased DNA rigidity and lengthening of cyclic DNA. Low doses of EB can induce DNA denaturation and can lead to cancer formation. And EB staining of bands is often used to facilitate high-resolution observations by optical microscope. However, conventional optical microscopy is unable to visualize potential aberrations of chromosome structures caused by EB treatment

关键词： Chromosome damage EtMdium Bromide （EB） atomic force microscope

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

控制理论与应用（英文版） 2005年第1期3卷 85-92页

作者： YongchunFANG MatthewFEEMSTER DarrenDAWSON NaderM.JALILI InstituteofRoboticsandAutomancInformationSystem NankaiUniversityTianjin300071China WeaponsandSystemEngineeringDeparment AnnapolisMarylandUSA21402-5025 ClemsonUniversity ClemsonSC29634-0915

Two nonlinear control techniques are proposed for an atomic force microscopesystem. Initially, a learning-based control algorithm is developed for the microcantilever-samplesystem that achieves asymptotic cantilever tip tracking for periodic trajectories. Specifically, thecontrol approach utilizes a learning-based feedforward term to compensate for periodic dynamics andhigh-gain terms to account for non-periodic dynamics. An adaptive control algorithm is thendeveloped to achieve asymptotic cantilever tip tracking for bounded tip trajectories despiteuncertainty throughout the system parameters. Simulation results are provided to illustrate theefficacy and performance of the control strategies.

关键词： atomic force microscope adaptive control learning control lyapunov-basedstability analysis

Visualization of Cellulose Microfibrils of Phyllostachys pubescens Fibers with atomic force microscope

在线全文

学校读者我要写书评

暂无评论

Chinese Forestry Science and Technology 2008年第3期7卷 32-37页

作者： YU Yan JIANG Zehui WANG Ge QIN Daochun CHENG Qiang International Centre for Bamboo and Rattan, Beijing 100102, P. R. China

atomic force microscope(AFM) was used to investigate the arrangement of cellulose microfibrils (CMF) in Moso bamboo (Phyllostachys pubescens) fibers. Two methods of sample preparation were used here for different purposes. The first method was chemical maceration with a mixture of hydrogen peroxide and glacial acetic acid, through which the obtained fibers were suitable for observing the orientation of CMF in the primary wal1. The other method was to prepare tangential microtomed sections with a thickness of approximately 30 μm, which was used to investigate the arrangement of CMF in the inner wall of cell cavity of bamboo fibers. The results indicated that the CMF are randomly oriented in the primary wall while in the inner wall of cell cavity they are nearly vertical to the long axis of fibers , which is similar to the arrangement of CMF in the corresponding layer of wood fibers. Meanwhile, the highly oriented arrangement of CMF is also observed in a certain layer of bamboo fibers, though it is incapable of determining which layer it is in this study. The pilot investigation demonstrates that AFM is a powerful tool for the high-resolution observation of CMF in bamboo fibers, meanwhile it has the advantages of simple procedure of sample preparation and easy operation compared to the traditional transmission electron microscopy.

关键词： Moso bamboo (Phyllostachys pubescens) cellulose microfibrils atomic force microscope

Observation of Ultrastructure of Polysaccharides from Chinese Jujube with Contact Mode atomic force microscope in the Air

在线全文

学校读者我要写书评

暂无评论

Observation of Ultrastructure of Polysaccharides from Chines...

Effects of Astragalus Polysaccharide on Mechanical Characterization of Liver Sinusoidal Endothelial Cells by atomic force Microscopy at Nanoscale

第五届全国化学生物学学术会议

作者： Jie Zhu~(1*) Lian-hong Guo~1 Bai-gang Zhang~2 Guo-dong Wang~1 1 College of Science,Northwest A&F University,Yangling 712100 China 2 College of Life Science and Engineering,Lanzhou University of Technology,Lanzhou,730050,China

＜正＞As the defoliating arbor,the jujube tree is the peculiar economic varieties of China.The jujube’s edible history in China has over 3,000 years,and there were plenty of gardens along the Yellow River valleys even in Zhou Dynasty.As the ‘king’ of fruits,the jujube fruit（commonly called as the Red Date）is sweet,delicious and nutritious,can be used as food or medicine which

关键词： Jujube Polysaccharides atomic force microscope Ultrafine Structure

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2018年第6期24卷 455-459页

作者： LU Wen-liang LI Juan-mei YANG Jiao XU Chen-guang ZHANG Sha-sha YAN Jie ZHANG Ting-ting ZHAO Hui-hui Department of Liver Diseases Guang'anmen Hospital China Academy of Chinese Medical Sciences Beijing 100053 China Department of Traditional Chinese Medicine The First People's Hospital of Huzhou Huzhou Zhejiang Province 313000 China Department of Traditional Chinese Medicine The First People's Hospital of Yuhang District Hangzhou 311100 China Department of Traditional Chinese Medicine Ningxia People's Hospital Yinchuan 750021 China

Objective： To study the effects of Astragalus polysaccharide （APS）, the primary effective component of the Chinese herb medicine Astragalus membranaceus （frequently used for its anti-hepatic fibrosis effects）, on nanoscale mechanical properties of liver sinusoidal endothelial cells （SECs）. Methods： Using endothelial cell medium as the control, 5 experimental groups were established utilizing different concentrations of APS, i.e. 12.5, 25, 50, 100, and 200μg/mL. By using atomic force microscopy along with a microcantilever modified with a silicon dioxide microsphere as powerful tools, the value of Young＇s modulus in each group was calculated. SAS 9.1 software was applied to analyze the values of Young＇s modulus at the pressed depth of 300 nm. Environmental scanning electron microscopy was performed to observe the surface microtopography of the SECs. Results： The value of Young＇s modulus in each APS experimental group was significantly greater than that of the control group： as APS concentration increased, the value of Young＇s modulus presented as an increasing trend. The difference between the low-concentration （12.5 and 25 μg/mL） and high-concentration （200μg/mL） groups was statistically significant （P〈0.05）, but no significant differences were observed between moderate-concentration （50 and 100μg/mL） groups versus low- or high-concentration groups （P〉0.05）. Surface topography demonstrated that APS was capable of increasing the total area of fenestrae. Conclusions： The values of Young＇s modulus increased along with increasing concentrations of APS, suggesting that the stiffness of SECs increases gradually as a function of APS concentration. The observed changes in SEC mechanical properties may provide a new avenue for mechanistic rasearch of anti-hepatic fibrosis treatments in Chinese medicine.

关键词： liver sinusoidal endothelial cell atomic force microscope Astragalus polysaccharide Young＇s modulus nanoscale Chinese medicine