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Optimization of dual effects of Mg–1Ca alloys on the behavior of chondrocytes and osteoblasts in vitro

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Progress in Natural Science:Materials International 2014年第5期24卷 433-440页

作者： Yana Dou Ayeesha Mujeeb Yufeng Zheng zigang ge Center for Biomedical Materials and Tissue Engineering Academy for Advanced Interdisciplinary Studies Peking University Department of Materials Science and Engineering College of Engineering Peking University Department of Biomedical Engineering College of Engineering Peking University Arthritis Clinic and Research Center Peking University People's Hospital

Mg ions can enhance the proliferation and redifferentiation of chondrocytes and the osteogenic differentiation of osteoblasts at specific concentrations, respectively. However, degradation of Mg alloys at varying degradation rates could lead to complex changes in the surrounding tissue environment, such as changes in the dynamic concentration of Mg ions and subsequent p H value. Considering the above mentioned factors, the comprehensive effects of Mg alloys on chondrocytes and osteoblasts behaviors have not yet been optimized. In this study, we evaluated the effects of Mg–1Ca microspheres on cell behavior with an aim to optimize conditions favorable for both cell types. Cells were cultured with Mg–1Ca microspheres prepared using the following concentrations: 250 μg/ml, 500 μg/ml and 1000 μg/ml. At specific time points,cytotoxicity, expression of specific genes and extracellular matrix deposition by cells(Alizarin Red Staining of osteoblasts and Alcian blue staining for chondrocytes) were evaluated. The experimental results revealed that Mg–1Ca microspheres prepared at a concentration of 250 μg/ml were optimum for both cell types, where chondrocytes were found to be in hypertrophy state while osteoblasts in close proximity to the microspheres showed osteogenetic differentiation. Interestingly, a slight change in osteoblasts behavior was observed nearer to and at a relative distance away from Mg–1Ca microspheres, an important observation for administering the application of microspheres as potential scaffolds.

关键词： Magnesium Degradation Chondrocyte Phenotype

Modified hyaluronic acid hydrogels with chemical groups that facilitate adhesion to host tissues enhance cartilage regeneration

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Bioactive Materials 2021年第6期6卷 1689-1698页

作者： Jiaqing Chen Jiabei Yang Li Wang Xuewei Zhang Boon Chin Heng Dong-An Wang zigang ge Department of Biomedical Engineering College of EngineeringPeking UniversityBeijing100871PR China School of Stomatology Peking UniversityBeijing100081PR China Department of Biomedical Engineering College of EngineeringCity University of Hong KongHong Kong SARPR China

Stable integration of hydrogel implants with host tissues is of critical importance to cartilage tissue *** and fabricating hydrogels with high adhesive strength,stability and regeneration potential are major challenges to be *** study fabricated injectable adhesive hyaluronic acid(HA)hydrogel modified by aldehyde groups and methacrylate(AHAMA)on the polysaccharide backbone with multiple anchoring mechanisms(amide bond through the dynamic Schiff base reaction,hydrogen bond and physical interpenetration).AHAMA hydrogel exhibited significantly improved durability and stability within a humid environment(at least 7 days),together with higher adhesive strength(43 KPa to skin and 52 KPa to glass),as compared to commercial fibrin glue(nearly 10 KPa)and HAMA hydrogel(nearly 20 KPa).The results showed that AHAMA hydrogel was biocompatible and could be easily and rapidly prepared in *** vitro cell culture experiments showed that AHAMA hydrogel could enhance proliferation(1.2-folds after 3 days)and migration(1.5-folds after 12 h)of bone marrow stem cells(BMSCs),as compared to cells cultured in a culture ***,in a rat osteochondral defect model,implanted AHAMA hydrogel significantly promoted integration between neo-cartilage and host tissues,and significantly improved cartilage regeneration(modified O’Driscoll histological scores of 16.0±4.1 and 18.3±4.6 after 4 and 12-weeks of post-implantation in AHAMA groups respectively,12.0±2.7 and 12.2±2.8 respectively in HAMA groups,9.8±2.4 and 11.5±2.1 respectively in untreated groups).Hence,AHAMA hydrogel is a promising adhesive biomaterial for clinical cartilage regeneration and other biomedical applications.

关键词： Cartilage regeneration Hydrogel Adhesion Schiff base reaction Hyaluronic acid Aldehyde

Nanosecond pulsed electric fields prime mesenchymal stem cells to peptide ghrelin and enhance chondrogenesis and osteochondral defect repair in vivo

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Science China(Life Sciences) 2022年第5期65卷 927-939页

作者： Kejia Li Litong Fan Jianjing Lin Boon Chin Heng Zhantao Deng Qiujian Zheng Jue Zhang Yangzi Jiang zigang ge Department of Biomedical Engineering College of EngineeringPeking UniversityBeijing 100871China Arthritis Clinical and Research Center Peking University People’s HospitalBeijing 100044China Arthritis Institute Peking UniversityBeijing 100871China Peking University School of Stomatology Beijing 100081China Department of Orthopedics Guangdong Provincial People’s HospitalGuangdong Academy of Medical SciencesGuangzhou 510080China Institute of Biomechanics and Biomedical Engineering College of EngineeringPeking UniversityBeijing 100871China Institute for Tissue Engineering and Regenerative Medicine School of Biomedical SciencesFaculty of MedicineThe Chinese University of Hong KongHong Kong 999077China School of Biomedical Sciences Faculty of MedicineThe Chinese University of Hong KongHong Kong 999077China Department of Biomedical Engineering College of Future TechnologyPeking UniversityBeijing 100871China

Mesenchymal stem cells(MSCs) are important cell sources in cartilage tissue development and homeostasis,and multiple strategies have been developed to improve MSCs chondrogenic differentiation with an aim of promoting cartilage *** we report the effects of combining nanosecond pulsed electric fields(ns PEFs) followed by treatment with ghrelin(a hormone that stimulates release of growth hormone) to regulate chondrogenesis of *** PEFs and ghrelin were observed to separately enhance the chondrogenesis of MSCs,and the effects were significantly enhanced when the bioelectric stimulation and hormone were combined,which in turn improved osteochondral tissue repair of these cells within Sprague Dawley *** further found that ns PEFs can prime MSCs to be more receptive to subsequent stimuli of differentiation by upregulated Oct4/Nanog and activated JNK signaling *** initiated chondrogenic differentiation by activation of ERK1/2 signaling pathway,and RNA-seq results indicated 243 genes were regulated,and JAK-STAT signaling pathway was ***,the sequential order of applying these two stimuli is critical,with ns PEFs pretreatment followed by ghrelin enhanced chondrogenesis of MSCs in vitro and subsequent cartilage regeneration in vivo,but not vice *** synergistic prochondrogenic effects provide us new insights and strategies for future cell-based therapies.

关键词： mesenchymal stem cells nanosecond pulsed electric fields ghrelin chondrogenic differentiation

A simple magnetic force-based cell patterning method using soft lithography

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Science China(Life Sciences) 2015年第4期58卷 400-402页

作者： LI ShanShan LIU XiangQi CHAU Alicia PENG XiaoLing GUIDO Isabella WANG LiLi ge zigang XIONG ChunYang Academy for Advanced Interdisciplinary Studies Peking University College of Engineering Peking University

Dear Editor,Cell patterning is gaining more and more attention regarding a wide range of applications including cell biology, tissue engineering, and biosensor technology, to name a few. Magnetic force provides a promising tool to pattern cells because it is of excellent biocompatibility, tunable and reversible, and can be employed flexibly in or out of the cell culture system [1]. While extensive studies [2-5] contribute valuable approaches for positioning cells with high resolution, costly and time-consuming fabrication procedures, such as electrodeposition and electrical discharge, still limit the application of these techniques.

关键词：细胞生物学图案磁力软光刻基础生物传感器生物相容性组织工程

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远程英语教学一对一辅导实验研究

中国远程教育 2009年第11期 46-49页

作者：葛子刚北京邮电大学网络教育学院

交互式教学被很多教师应用在远程教学之中,但到底应该采取什么样的交互形式目前还没定论。为了检验远程教学中不同辅导方式在教学效果方面的差异,本研究以北京邮电大学网络教育学院的两个班级为实验对象,就一对多辅导形式和一对一辅导... 详细信息

交互式教学被很多教师应用在远程教学之中,但到底应该采取什么样的交互形式目前还没定论。为了检验远程教学中不同辅导方式在教学效果方面的差异,本研究以北京邮电大学网络教育学院的两个班级为实验对象,就一对多辅导形式和一对一辅导形式在远程英语教学中的效果进行了对比分析。实验结果表明,一对一辅导比一对多辅导具有更好的教学效果,可以更好地促进学生的学习参与,更有助于了解学生的学习状态。

关键词：远程教学一对多辅导一对一辅导

Key considerations on the development of biodegradable biomaterials for clinical translation of medical devices:With cartilage repair products as an example

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Bioactive Materials 2022年第3期7卷 332-342页

作者： Li Wang Xiaolei Guo Jiaqing Chen Zhen Zhen Bin Cao Wenqian Wan Yuandong Dou Haobo Pan Feng Xu Zepu Zhang Jianmei Wang Daisong Li Quanyi Guo Qing Jiang Yanan Du Jiakuo Yu Boon Chin Heng Qianqian Han zigang ge Department of Biomedical Engineering College of EngineeringPeking UniversityBeijingPR China Center for Medical Device Evaluation National Medical Products AdministrationBeijingPR China Jiangsu DissueTech Medical Technology Co.Ltd|DeJian Group SuzhouPR China State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghaiPR China Research Center for Human Tissue and Organs Degeneration Shenzhen Institute of Advanced TechnologyChinese Academy of ScienceShenzhenPR China Bioinspired Engineering and Biomechanics Center(BEBC) MOE Key Laboratory of Biomedical Information EngineeringSchool of Life Science and TechnologyXi’an Jiaotong UniversityXi’anPR China Beijing Institute of Science and Technology Evaluation BeijingPR China Institute of Orthopedics Chinese PLA General HospitalBeijingPR China Department of Sports Medicine and Adult Reconstructive Surgery State Key Laboratory of Pharmaceutical BiotechnologyThe Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical SchoolNanjingPR China Department of Biomedical Engineering School of MedicineTsinghua UniversityBeijingPR China Knee Surgery Department of the Institute of Sports Medicine Beijing Key Laboratory of Sports InjuriesPeking University Third HospitalBeijingPR China School of Stomatology Peking UniversityBeijingPR China National Institutes for Food and Drug Control BeijingPR China Department of Biomedical Engineering Institute of Future TechnologyPeking UniversityBeijingPR China

With the interdisciplinary convergence of biology,medicine and materials science,both research and clinical translation of biomaterials are progressing at a rapid ***,there is still a huge gap between applied basic research on biomaterials and their translational products-medical devices,where two significantly different perspectives and mindsets often work independently and non-synergistically,which in turn significantly increases financial costs and research *** this gap is well-known and often criticized in the biopharmaceutical industry,it is gradually *** this article,we critically examine the developmental pipeline of biodegradable biomaterials and biomaterial-based medical device *** based on clinical needs,market analysis,and relevant regulations,some ideas are proposed to integrate the two different mindsets to guide applied basic research and translation of biomaterial-based products,from the material and technical *** repair substitutes are discussed here as an ***,this will lay a strong foundation for biomaterial research and clinical translation,while reducing the amount of extra research effort and funding required due to the dissonance between innovative basic research and commercialization pipeline.

关键词： Biomaterials Polymer Translation Medical devices Regulation Clinical needs

Controllability of Semilinear Integrodifferential Degenerate Sobolev Equations

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Journal of Systems Science & Complexity 2024年第5期37卷 1923-1936页

作者： ge Zhaoqiang School of Mathematics and Statistics Xi’an Jiaotong University

In this paper, the approximate controllability of semilinear integrodifferential degenerate Sobolev equations with nonlocal conditions is investigated in the sense of integral solution in Hilbert spaces. Some sufficient and necessary conditions are obtained. Firstly, the existence and uniqueness of integral solutions of semilinear integrodifferential degenerate Sobolev equations with nonlocal conditions are considered by ge-evolution operator theory and Sadovskii's fixed point theorem, the existence and uniqueness theorem of solutions is given. Secondly, the approximate controllability of semilinear integrodifferential degenerate Sobolev equations with nonlocal conditions is studied in the sense of integral solution. The criterion for approximate controllability is provided. The obtained results have important theoretical and practical value for the study of controllability of semilinear integrodifferential degenerate Sobolev equations with nonlocal conditions.

关键词： Approximate controllability ge-evolution operator integral solution Sadovskii’s fixed point theorem semilinear integrodifferential degenerate Sobolev equations

Polymeric piezoelectric accelerometers with high sensitivity,broad bandwidth,and low noise density for organic electronics and wearable microsystems

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Microsystems & Nanoengineering 2024年第3期10卷 63-74页

作者： Chang ge Edmond Cretu The Department of Electrical and Computer Engineering The University of British ColumbiaVancouverBCCanada

Piezoelectric accelerometers excel in vibration *** the emerging trend of fully organic electronic microsystems,polymeric piezoelectric accelerometers can be used as vital front-end components to capture dynamic signals,such as vocal vibrations in wearable speaking assistants for those with speaking ***,high-performance polymeric piezoelectric accelerometers suitable for such applications are *** organic compounds such as PVDF have inferior properties to their inorganic counterparts such as ***,most existing polymeric piezoelectric accelerometers have very unbalanced performance *** often sacrifice resonance frequency and bandwidth for a flat-band sensitivity comparable to those of PZT-based accelerometers,leading to increased noise density and limited application *** this study,a new polymeric piezoelectric accelerometer design to overcome the material limitations of PVDF is *** new design aims to simultaneously achieve high sensitivity,broad bandwidth,and low *** samples were manufactured and characterized,demonstrating an average sensitivity of 29.45 pC/g within a±10 g input range,a 5%flat band of 160 Hz,and an in-band noise density of 1.4μg/√*** results surpass those of many PZT-based piezoelectric accelerometers,showing the feasibility of achieving comprehensively high performance in polymeric piezoelectric accelerometers to increase their potential in novel applications such as organic microsystems.

关键词： piezoelectric polymeric overcome

Meridional deflection of global eddy propagation derived from tandem altimetry: Mechanism and implication

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Science China Earth Sciences 2024年第3期67卷 811-825页

作者： ge CHEN Xiaoyan CHEN Frontiers Science Center for Deep Ocean Multispheres and Earth System School of Marine TechnologyOcean University of ChinaQindao 266100China Laboratory for Regional Oceanography and Numerical Modeling Laoshan LaboratoryQindao 266237China

A common view on meridional deflection of eddy propagation is poleward for cyclones and equatorward for anticyclones. This widely accepted polarity-sensitive pattern has been increasingly undermined given that it is systematically violated on both zonal and regional scales as recently reported. Here, we approach the problem by exploring these violations in terms of eddy effects of spatiotemporal geostrophy, thermal fading, and flow dragging, yielding the following main conclusions.(1) The polarity-dependent deflection discrepancy is a pseudo feature resulting from a biased fit to the normalized eddy tracks which are spatially asymmetric(though azimuthally symmetric) between the two signs;Instead, the primary pattern of eddy deflection appears to be geographically correlated and polarity independent.(2) geostrophic adjustment plays a critical role in defining the meridional movement of an eddy. Specifically, a consistent poleward(equatorward) trajectory bending of spatially(temporally) ageostrophic eddies is observed irrespective of their polarity.(3) The mechanism of eddy deflection is also determined by its zonal propagation direction. Westward propagating eddies are substantially affected by thermal fading, while opposite ones by flow dragging. A realistic and comprehensive understanding of eddy deflection mechanisms serves as a significant contribution to the prediction of eddy trajectory, and the protection of ocean environment.

关键词： Mesoscale eddies Eddy propagation Eddy meridional deflection Satellite observation geostrophic adjustment