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Fabrication of three-dimensional islet models by geometry-controlled hanging drop method

Acta Mechanica Sinica 2019年第2期35卷 329-337页

作者： Bin Gao Ce Jing Kelvin Ng Belinda Pingguan-Murphy Qingzhen Yang Department of Endocrinology and Metabolism The First Affiliated Hospital Air Force Military Medical University Xi’an 710032 China Outpatient Department of Lanzhou Military Region 940 Hospital Joint Logistics Support Force of the People's Liberation Army of China Lanzhou 730000 China Department of Biomedical Engineering Faculty of Engineering University of Malaya Kuala Lumpur 50603 Malaysia Key Laboratory of Biomedical Information Engineering of Ministry of Education School of Life Science and Technology Xi'an Jiaotong University Xi'an 710049 China Bioinspired Engineering and Biomechanics Center (BEBC) Xi’an Jiaotong University Xi’an 710049 China

Hanging-drop method has been widely used to fabricate three-dimensional (3D) in vitro tissue models due to its advantages such as being easy to perform, inexpensive, and permitting precise control of cell spheroid formation. The geometry of hanging drop may play a critical role on the formation of cell spheroids, which, however, has not been explored. In this study, we developed a modified hanging-drop platform that enables the production of cell spheroids in a high-throughput manner by controlling hanging drop geometry with defined spreading ring. The surface tension force is proportional to the spreading ring and gravitational force is determined by the droplet volume, and the geometry can be determined by the balance between surface tension and gravity.β-TC-6 cell spheroids with optimized diameters were fabricated as 3D in vitro islet models. The models show morphology similar to primary islets and have functionality that more closely resembles primary islets than two-dimensional cell culture. The developed platform holds great potential for engineering well-controlled in vitro tissue models for various applications such as physiological and pathological studies, drug screening, as well as transplantation for treatment purpose.

关键词： Hanging drop cell culture Mechanical microenvironment Drop geometry 3D islet spheroids

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Inner-shell photoabsorption spectra——A theoretical study to determine the geometry structure of the core excited methane

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Science China Mathematics 2000年第8期43卷 871-877页

作者：张卫华钟志萍李家明 Department of Physics Center of Atomic and Molecular Sciences Tsinghua University Beijing 100084 China

Based on multi-scattering self-consistent field method, the photoabsorption spectra near C 1s threshold of CH4(near-threshold structure) have been studied with the broken symmetry from Td. The most possible geometry of the core excited CH4** is determined as the C3v symmetry; the core excited CH4** molecules have the same bond angle (109.5? as that of the ground state CH4 and consist of one shorter bond length (1.91 a. u.) and three longer bond lengths (2.04 a. u.). The three longer bond lengths are almost the same as that of the ground state CH4, and the averaged bond length (2.01 a.u.) of core excited CH4** is shorter than that of the ground state CH4(2.06 a.u.).

关键词： molecular geometry inner-shell photoabsorption near-threshold structures methane.

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A unified curvature theory in kinematic geometry of mechanism

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Science China(Technological Sciences) 1998年第2期41卷 196-202页

作者：王德伦刘健肖大准 Department of Mechanical Engineering Dalian University of Technology Dalian China

Based on the differential geometry, the expressions of centrodes and axodes as well as their invariants are derived. And then, the kinematic meanings of them are revealed. Meanwhile, the properties of a point trajectory in planar, spherical and spatial motion or a line trajectory in spatial motion are discussed. A main clue for the unified curvature theory in kinematic geometry of mechanism is set up in the form and content from plane to space motion.

关键词： curvature theory kinematic geometry of mechanism differential geometry.

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Restoration of the joint geometry and outcome after stemless TESS shoulder arthroplasty

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World Journal of Orthopedics 2017年第10期8卷 790-797页

作者： Lars V von Engelhardt Michael Manzke Andreas Breil-Wirth Timm J Filler Joerg Jerosch Faculty of Health University of Witten/Herdecke Department of Orthopedics Trauma Surgery and Sports MedicineJohanna Etienne Hospital Department of Anatomy Heinrich-Heine University of Duesseldorf

AIM To evaluate the joint geometry and the clinical outcome of stemless, anatomical shoulder arthroplasty with the TESS system.METHODS Twenty-one shoulders with a mean follow-up 18 of months were included. On scaled digital radiographs the premorbid center of rotation(CoR) was assessed and compared to the CoR of the prosthesis by using the MediC AD~? software. Additionally, the pre-and post-operative geometry of the CoR was assessed in relation to the glenoid, the acromion as well as to the proximal humerus. Radiological changes, such as radiolucencies, were also assessed. Clinical outcome was assessed with the Constant and DASH score. RESULTS Both, the Constant and DASH scores improved signifi-cantly from 11% to 75% and from 70 to 30 points, P 0.05). The pre-and postoperative humeral offset, the lateral glenohumeral offset, the height of the CoR, the acromiohumeral distance as well as neckshaft angle showed no significant changes(P > 0.05). The mean deviation of the CoR of the prosthesis from the anatomic center was 1.0 ± 2.8 mm. Three cases showed a medial deviation of more than 3 mm. These deviations of 5.1, 5.7 and 7.6 mm and were caused by an inaccurate humeral neck cut. These 3 patients showed a relatively poor outcome scoring.CONCLUSION TESS arthroplasty allows an anatomical joint reconstruction with a very good outcome. Outliers described in this study sensitize the surgeon for an accurate humeral neck cut.

关键词： Anatomical shoulder arthroplasty Stemless Omarthrosis Total shoulder replacement Joint geometry

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Closed form of the inverse Plücker correspondence in line geometry

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Science China Mathematics 2019年第12期62卷 2617-2630页

作者： Lei Dong Hongbo Li Lei Huang Changpeng Shao Key Laboratory of Mathematics Mechanization Academy of Mathematics and Systems ScienceChinese Academy of Sciences

By mapping the homogeneous coordinates of two points in space to the Plücker coordinates of the line they determine, any transformation of type SL(4) upon points in space is mapped to a transformation of type SO0(3, 3), the latter being the connected component containing the identity of the special orthogonal transformation group of the linear space spanned by Plücker coordinates. This is the classical Plücker correspondence, two-to-one and onto. It has important applications in line geometry and projective transformations.While the explicit form of Plücker correspondence is trivial to present, its inverse in explicit form, which is also important in application, is not found in the literature. In this paper, we present a simple and unified formula for the inverse of the Plücker correspondence.

关键词： Plücker correspondence inverse Plücker correspondence line geometry SL(4) SO(3,3)

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Assessing the oscillation of channel geometry and meander migration cardinality of Bhagirathi River,West Bengal,India

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Journal of Geographical Sciences 2019年第4期29卷 613-634页

作者： Rakhohori Bag Ismail Mondal Jatisankar Bandyopadhyay Department of Remote Sensing&GIS Vidyasagar UniversityMidnapore-721102India Department of Marine Science University of CalcuttaKolkata-700019India

Lateral migration of the Bhagirathi River temporally creates unavoidable geomorphic hazards in West Bengal,India.The Bhagirathi River flows SW for-67.30 km betwee n the confluenee point of Ajay and Jalangi rivers in East Burdwan and Nadia districts of West Bengal.The course of Bhagirathi is notably migration prone and cultivates problematic changes along its course over time.In the study,we have looked into its migration tendency and unpredictability for past 238 years and then predicted the lateral shifting of river centerline using temporal satellite imageries-Landsat-5(TM)of 1987(8,December),1995(28,January),2005(7,January)and LISS-IV satellite imagery(2017,5 January);SOI Toposheet-1968-1969(79A/2,79A/3,79A/6 and 79A/7)and RennelPs map of 1779.Other highlights are the quest of fluvial features,oxbow lakes,mid-channel bars,channel migration rate,meander geometry,channel sinuosity in different parts of river course and the parts that experience intensive bank erosion.The entire river course has been subdivided into three segments;viz.reaches A,B and C.Investigation displays that degree of sinuosity decreases from its anterior course(1968)to the existing course(2017).Reach-specific outputs display that reach B is highly sinuous(SI value 1.94 in 2017)and SI increases temporarily,whereas for reaches A and C it decreases with time.The rate of migration is higher in reach B than that in reaches C and A.The study displays a notably decreasing trend of migration in comparison with its previous lateral migration and shows that the migration nature over time is intensively inconsistent and unpredictable except very few portions of the river course.The nature of deposition within the river channel shows an unstable behavior during the entire period of the study.Meander geometry depicts a rapid change of river course innate to meander bends and shows a higher rate of migration by meander loop cut-off rather than lateral migration that reflects the inconsistency,erosion vulnerability and unpredictable nature of migration.Th

关键词： channel geometry sinuosity index braiding index meander geometry radius of curvature bend tightness index linear regression GIS

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Spatio-temporal Characteristics of Area Coverage and Observation geometry of the MISR Land-surface BRF Product: A Case Study of the Central Part of Northeast Asia

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Chinese Geographical Science 2019年第4期29卷 679-688页

作者： LI Jian CHEN Shengbo QIN Wenhan Mike MUREFU WANG Yufei YU Yan ZHEN Zhijun College of Geo-Exploration Science and Technology Jilin UniversityChangchun 130026 China Climate Centre of Jilin Province Changchun 130062 China

The Multi-angle imaging spectroradiometer(MISR) land-surface(LS) bidirectional reflectance factor(BRF) product(MILS_BRF) has unique semi-simultaneous multi-angle sampling and global coverage. However, unlike on-satellite observations, the spatio-temporal characteristics of MILS_BRF data have rarely been explicitly and comprehensively analysed. Results from 5-yr(2011–2015) of MILS_BRF dataset from a typical region in central Northeast Asia as the study area showed that the monthly area coverage as well as MILS_BRF data quantity varies significantly, from the highest in October(99.05%) through median in June/July(78.09%/75.21%) to lowest in January(18.97%), and a large data-vacant area exists in the study area during four consecutive winter months(December through March). The data-vacant area is mainly composed of crop lands and cropland/natural vegetation mosaic. The amount of data within the principal plane(PP)±30°(nPP) or cross PP ±30°(nCP), varies intra-annually with significant differences from different view zeniths or forward/backward scattering directions. For example, multiple off-nadir cameras have nPP but no nCP data for up to six months(September through February), with the opposite occurring in June and July. This study provides explicit and comprehensive information about the spatio-temporal characteristics of product coverage and observation geometry of MILS_BRF in the study area. Results provide required user reference information for MILS_BRF to evaluate performance of BRDF models or to compare with other satellite-derived BRF or albedo products. Comparing this final product to on-satellite observations, what was found here reveals a new perspective on product spatial coverage and observation geometry for multi-angle remote sensing.

关键词： multi-angle remote sensing Multi-angle Imaging Spectroradiometer (MISR) bidirectional reflectance factor (BRF) spatio-temporal characteristics observation geometry

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Design and implementation of web-based dynamic geometry drawing technology

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The Journal of China Universities of Posts and Telecommunications 2019年第6期26卷 43-53页

作者： Guan Hao Rao Yongsheng Xu Zhangtao Chengdu Institute of Computer Application Chinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China Institute of Computing Science and Technology Guangzhou UniversityGuangzhou 510006China School of Mathematics and Statistics Central China Normal UniversityWuhan 430079China

Dynamic geometry software, as a piece of computer-assisted instruction(CAI) software, is closely and deeply associated with mathematics, and is widely applied to mathematics teaching activities in primary and secondary schools. Meanwhile, web technology also has become an important technology for assisting education and teaching. This paper expounds a web-based dynamic geometry software development process, and analyses specific requirements regarding graphical application programming interface(API) required by dynamic geometry software. With experiments and comparison on the two different hypertext markup language(HTML)5 graphical API technologies, i.e., scalable vector graphics(SVG) and Canvas, on different apparatuses and browsers, we draw the conclusion that it is more suitable to adopt Canvas as the graphical API technology for the web-based dynamic geometry software, thus further proposed the principles and methods for an object-oriented Canvas design. The dynamic geometry software based on the newly-designed Canvas has technical advantages and educational value, well incorporating aesthetic education into mathematics education.

关键词： web Canvas dynamic geometry subject tools

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Fibrations and stability for compact group actions on manifolds with local bounded Ricci covering geometry

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Frontiers of Mathematics in China 2020年第1期15卷 69-89页

作者： Hongzhi HUANG School of Mathematical Sciences Capital Normal UniversityBeijing 100048China

In the study of the collapsed manifolds with bounded sectional curvature,the following two results provide basic tools:a(singular)fibration theorem by K.Fukaya[J.Differential Gcom.,1987.25(1):139156]and J.Cheeger,K.Fukaya,and M.Gromov[J.Airier.Math.Soc.,1992.5(2):327372],and the stability for isometric compact Lie group actions on manifolds by R.S.Palais[Bull.Amer.Math.Soc.,1961,67(4):362364]and K.Grove and H.Karcher[Math.Z..1973,132:1120].The main results in this paper(partially)generalize the two results to manifolds with local bounded Ricci covering geometry.

关键词： Fibrations stability for group actions nilpotent structures Ricci curvature bounded Ricci covering geometry

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A geometry characteristic of Banach spaces with c^1-norm

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Frontiers of Mathematics in China 2014年第5期9卷 1089-1103页

作者： Jipu MA Department of Mathematics Nanjing University Nanjing 210093 China

Let E be a Banach space with the cl-norm｜｜·｜｜ in E／{0}, and let S（E） = {e ∈ E：｜｜e｜｜ = 1}. In this paper, a geometry characteristic for E is presented by using a geometrical construct of S（E）. That is, the following theorem holds： the norm of E is of eI in E／{0} if and only if S（E） is a c1 submanifold of E, with codimS（E） = 1. The theorem is very clear, however, its proof is non-trivial, which shows an intrinsic connection between the continuous differentiability of the norm ｜｜·｜｜ in E／{0} and differential structure of S（E）.

关键词： Banach space geometry non-linear analysis global analysis

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