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Ant colonization increased total mercury but reduced methylmercury contents in boreal mires, Northeast China

Journal of Environmental Sciences 2022年第9期34卷 50-58页

作者： Zhongsheng zhang xuehui zhang Yuan Xin Haitao Wu Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchun 130012China University of Chinese Academy of Sciences Beijing 100049China Shengyang University Shenyang 110044China

Soil macroinvertebrates as ecosystem engineers play significant, but largely ignored, roles in affecting mercury(Hg) cycle by altering soil physical-chemical properties. Ant is likely expanded into boreal mires with climate warming, however, its impacts on Hg cycle remained poorly understood. We compared total Hg(THg) and methylmercury(Me Hg) contents in soils from antmounds( Lasius flavus) and the nearby ambient in a boreal mire in Northeast China. The present work seeks to unravel factors that controlling Me Hg levels in case of ant appearance or absence. The average THg was 179 μg/kg in the ant mound and was 106.1 μg/kg in nearby soils, respectively. The average Me Hg was 10.9 μg/kg in the ant mound and was 12.9 μg/kg in nearby soils, respectively. The ratios of Me Hg to THg(%Me Hg) were 7.61% in ant mounds and 16.75% in nearby soils, respectively. Ant colonization caused THg enrichment and Me Hg depletion, and this change was obvious in the 10-20 cm depth soil layer where ants mainly inhabited. Spectrometry characteristics of soil dissolved organic matter(DOM) exert a stronger control than microorganisms on Me Hg variation in soils. A structural equation model revealed that the molecular weight of DOM inhibited Me Hg irrespective of ant presence or absence, while humification conducive to Me Hg significantly in ant mound soils. Microorganisms mainly affected Hg methylation by altering the molecular weight and humification of DOM. We propose that the effects of ant colonization on Me Hg rested on DOM feature variations caused by microorganisms in boreal mires.

关键词： Ant colonization Mercury Methylmercury Boreal mire DOM spectrometry

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Extrapolating neurogenesis of mesenchymal stem/stromal cells on electroactive and electroconductive scaffolds to dental and oral-derived stem cells

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International Journal of Oral Science 2022年第2期14卷 123-131页

作者： Boon Chin Heng Yunyang Bai Xiaochan Li xuehui zhang Xuliang Deng Central Laboratory Peking University School and Hospital of StomatologyBeijingChina School of Medical and Life Sciences Sunway UniversitySubang JayaSelangor Darul EhsanMalaysia Department of Geriatric Dentistry Peking University School and Hospital of StomatologyBeijingChina Department of Dental Materials&Dental Medical Devices Testing Center Peking University School and Hospital of StomatologyBeijingChina National Engineering Laboratory for Digital and Material Technology of Stomatology NMPA Key Laboratory for Dental MaterialsBeijing Laboratory of Biomedical Materials&Beijing Key Laboratory of Digital StomatologyPeking University School and Hospital of StomatologyBeijingChina

The high neurogenic potential of dental and oral-derived stem cells due to their embryonic neural crest origin,coupled with their ready accessibility and easy isolation from clinical waste,make these ideal cell sources for neuroregeneration therapy.Nevertheless,these cells also have high propensity to differentiate into the osteo-odontogenic lineage.One strategy to enhance neurogenesis of these cells may be to recapitulate the natural physiological electrical microenvironment of neural tissues via electroactive or electroconductive tissue engineering scaffolds.Nevertheless,to date,there had been hardly any such studies on these cells.Most relevant scientific information comes from neurogenesis of other mesenchymal stem/stromal cell lineages(particularly bone marrow and adipose tissue)cultured on electroactive and electroconductive scaffolds,which will therefore be the focus of this review.Although there are larger number of similar studies on neural cell lines(i.e.PC12),neural stem/progenitor cells,and pluripotent stem cells,the scientific data from such studies are much less relevant and less translatable to dental and oral-derived stem cells,which are of the mesenchymal lineage.Much extrapolation work is needed to validate that electroactive and electroconductive scaffolds can indeed promote neurogenesis of dental and oral-derived stem cells,which would thus facilitate clinical applications in neuroregeneration therapy.

关键词： mesenchymal conductive neural

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Investigation of the first quasi-rectangular metro tunnel constructed by the 0-θ method

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Frontiers of Structural and Civil Engineering 2023年第11期17卷 1707-1722页

作者： Peinan LI Xue LIU Xi JIANG xuehui zhang Jun WU Peixin CHEN College of Environmental Science and Engineering Donghua UniversityShanghai 201620China Department of Civil and Environmental Engineering University of TennesseeKnoxvilleTN 37996USA Department of Geoscience and Engineering Delft University of TechnologyDelft 2628The Netherlands College of Urban Railway Transportation Shanghai University of Engineering ScienceShanghai 201620China Shanghai Tunnel Engineering Co..Ltd. Shanghai 200032China

Quasi-rectangular shield tunneling is a cutting-edge trenchless method for constructing metro tunnels with double tubes,owing to its advantages in saving underground space and reducing ground disturbance.However,the conventional quasi-rectangular shield tunneling method is not applicable when constructing a tunnel without a center pillar,such as a scissor crossover section of a metro line.Therefore,the O-0 tunneling method,which combines the quasirectangular shield and pipe jacking methods,was investigated in this study to solve the aforementioned construction challenges.This study presents a case study of the Sijiqing Station of the Hangzhou Metro Line 9 in China,in which the O-0 method was first proposed and applied.Key techniques such as switching between two types of tunneling modes and the tunneling process control in complex construction environments were investigated.The results demonstrated that the O-0 method can address the technical challenges presented by the post-transition line with a high curvature and a scissors crossover line.In addition,the adoption of the 0-0 method ensured that the transformation between shield tunneling and pipe jacking was safe and efficient.The ground settlement monitoring results demonstrated that the disturbance to the surrounding environment can be limited to a safe level.This case study contributes to the construction technology for a metro tunnel containing both post-transition lines with a small turning radius and a scissors crossover line.A practical construction experience and theoretical guidance were provided in this study,which are of significance for both the industry and academia.

关键词： quasi-rectangular tunnel O-0 method pipe jacking shield tunneling underground space

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Electrical charge on ferroelectric nanocomposite membranes enhances SHED neural differentiation

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Bioactive Materials 2023年第2期20卷 81-92页

作者： Xiaochan Li Boon Chin Heng Yunyang Bai Qianqian Wang Min Gao Ying He Xinwen zhang Xuliang Deng xuehui zhang Department of Geriatric Dentistry Peking University School and Hospital of StomatologyBeijing100081PR China Department of Dental Materials&Dental Medical Devices Testing Center Peking University School and Hospital of StomatologyBeijing100081PR China Department of Prosthodontics Peking University School and Hospital of StomatologyBeijing100081PR China Central Laboratory Peking University School and Hospital of StomatologyBeijing100081PR China Center of Implant Dentistry School and Hospital of StomatologyChina Medical UniversityLiaoning Provincial Key Laboratory of Oral DiseasesShenyang110002PR China National Engineering Research Center of Oral Biomaterials and Digital Medical Devices NMPA Key Laboratory for Dental MaterialsBeijing Laboratory of Biomedical MaterialsPeking University School and Hospital of StomatologyBeijing100081PR China

Stem cells from human exfoliated deciduous teeth(SHED)uniquely exhibit high proliferative and neurogenic potential.Charged biomaterials have been demonstrated to promote neural differentiation of stem cells,but the dose-response effect of electrical stimuli from these materials on neural differentiation of SHED remains to be elucidated.Here,by utilizing different annealing temperatures prior to corona poling treatment,BaTiO_(3)/P(VDF-TrFE)ferroelectric nanocomposite membranes with varying charge polarization intensity(d_(33)≈0,4,12 and 19 pC N^(-1))were fabricated.Enhanced expression of neural markers,increased cell elongation and more prominent neurite outgrowths were observed with increasing surface charge of the nanocomposite membrane indicating a dose-response effect of surface electrical charge on SHED neural differentiation.Further investigations of the underlying molecular mechanisms revealed that intracellular calcium influx,focal adhesion formation,FAK-ERK mechanosensing pathway and neurogenic-related ErbB signaling pathway were implicated in the enhancement of SHED neural differentiation by surface electrical charge.Hence,this study confirms the dose-response effect of biomaterial surface charge on SHED neural differentiation and provides preliminary insights into the molecular mechanisms and signaling pathways involved.

关键词： Surface charge Electric polarization Dose-response effect Electrical microenvironment Neurogenesis

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The bioelectrical properties of bone tissue

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Animal Models and Experimental Medicine 2023年第2期6卷 120-130页

作者： Boon Chin Heng Yunyang Bai Xiaochan Li Yanze Meng Yanhui Lu xuehui zhang Xuliang Deng Department of Dental Materials&Dental Medical Devices Testing Center Peking University School and Hospital of StomatologyBeijingPR China Central Laboratory Peking University School and Hospital of StomatologyBeijingPR China School of Medical and Life Sciences Sunway UniversitySubang JayaMalaysia Department of Geriatric Dentistry Peking University School and Hospital of StomatologyBeijingPR China National Engineering Research Center of Oral Biomaterials and Digital Medical Devices NMPA Key Laboratory for Dental MaterialsBeijing Laboratory of Biomedical Materials&Beijing Key Laboratory of Digital StomatologyPeking University School and Hospital of StomatologyBeijingPeople's Republic of China

Understanding the bioelectrical properties of bone tissue is key to developing new treatment strategies for bone diseases and injuries,as well as improving the design and fabrication of scaffold implants for bone tissue engineering.The bioelectrical properties of bone tissue can be attributed to the interaction of its various cell lineages(osteocyte,osteoblast and osteoclast)with the surrounding extracellular matrix,in the presence of various biomechanical stimuli arising from routine physical activities;and is best described as a combination and overlap of dielectric,piezoelectric,pyroelectric and ferroelectric properties,together with streaming potential and electro-osmosis.There is close interdependence and interaction of the various electroactive and electrosensitive components of bone tissue,including cell membrane potential,voltage-gated ion channels,intracellular signaling pathways,and cell surface receptors,together with various matrix components such as collagen,hydroxyapatite,proteoglycans and glycosaminoglycans.It is the remarkably complex web of interactive cross-talk between the organic and non-organic components of bone that define its electrophysiological properties,which in turn exerts a profound influence on its metabolism,homeostasis and regeneration in health and disease.This has spurred increasing interest in application of electroactive scaffolds in bone tissue engineering,to recapitulate the natural electrophysiological microenvironment of healthy bone tissue to facilitate bone defect repair.

关键词： bone dielectric electric ferroelectric homeostasis metabolism piezoelectric pyroelectric regeneration

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Research on Career Identity in China:A Literature Review

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International Journal of Mental Health Promotion 2023年第2期25卷 153-172页

作者： Huaruo Chen Ya Wen Fei Liu Yihong Zhao Zhiyao Xie xuehui zhang College of Education Science and Technology Nanjing University of Posts and TelecommunicationsNanjing210023China Center for Research and Reform in Education Johns Hopkins UniversityBaltimore21218USA School of Teachers and Education Nanjing Xiaozhuang UniversityNanjing211171China School of Education Science Nanjing Normal UniversityNanjing210097China School of Education Science Huaiyin Normal UniversityHuai’an223300China Publicity Department of Weifang Municipal Committee Weifang261071China Jiangsu Health Vocational College Nanjing210029China

Career identity is one of the important topics to study the psychological problems of employees,especially after the outbreak of CoV-19.Being a populous country in the world,China has a large number of employees from all walks of life,and its research on career identity has attracted more and more attention.Thus,this study aims to sort out the history,characteristics,and trends of the research on career identity in China through a literature review,which can help more scholars pay attention to China’s career identity research.In this study,Citespace is used to statistically analyze the selected literature from China’s National Knowledge Infrastructure(CNKI)and Web of Science(WOS).The results show that:(1)The historical evolution of career identity research in China can be divided into three stages:germination,development and maturity.(2)From the perspective of cooperation between authors and institutions,researchers tend to do independent research,mainly focusing on the research in the field of psychology.(3)From the key words,career identity and employability are the main high-frequency words.(4)From the cluster analysis,the research focuses mainly include social support,teachers’career identity,influencing factors,and job involvement.(5)From the emergent analysis,it can be seen that the research on roles and differences between urban and rural areas is weakening,and the research on factors such as job satisfaction is gradually strengthening as the frontier theme.Finally,according to the existing analysis results,this study predicts the future trend of career identity in China and thinks that it will extend from the fields of concept explanation,interdisciplinary research,scientific research tools,and so on.

关键词： Career identity scientific knowledge maps historical evolution research hot spot career education

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Comparative study on foundation treatment methods of immersed tunnels in China

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Frontiers of Structural and Civil Engineering 2020年第1期14卷 82-93页

作者： Shaochun WANG xuehui zhang Yun BAI Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China

Based on engineering practices of four typical traffic immersed tunnels built in China,this paper details the features of the four dominant foundation treatment methods for immersed tunnel construction:pile foundation,sand flow foundation,grouting foundation,and gravel bedding foundation.Subsoil stress time-history of different method are specified first,plus a summary of settlement assessment method for foundation quality control.Further,a comprehensive comparison of settlement and cost of these four foundation treatment methods is conducted to highlights the specific merits,disadvantages and conditions encountered in each foundation treatment method,based on real projects information.The findings of this article could henceforth be applied to foundation treatment work in immersed tube tunnel construction.

关键词： foundation treatment method immersed tunnel subsoil stress settlement

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Matrix stiffness modulates tip cell formation through the p-PXN-Rac1-YAP signaling axis

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Bioactive Materials 2022年第1期7卷 364-376页

作者： Yaru Guo Feng Mei Ying Huang Siqin Ma Yan Wei xuehui zhang Mingming Xu Ying He Boon Chin Heng Lili Chen Xuliang Deng Department of Geriatric Dentistry Peking University School and Hospital of StomatologyBeijing100081China Department of Stomatology Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430022China Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration Wuhan430022China Department of Dental Materials Peking University School and Hospital of StomatologyBeijing100081PR China National Engineering Laboratory for Digital and Material Technology of Stomatology Beijing100081PR China Beijing Laboratory of Biomedical Materials Peking University School and Hospital of StomatologyBeijing100081PR China Central Laboratory Peking University School and Hospital of StomatologyBeijing100081PR China

Endothelial tip cell outgrowth of blood-vessel sprouts marks the initiation of angiogenesis which is critical in physiological and pathophysiological procedures.However,how mechanical characteristics of extracellular matrix(ECM)modulates tip cell formation has been largely neglected.In this study,we found enhanced CD31 expression in the stiffening outer layer of hepatocellular carcinoma than in surrounding soft tissues.Stiffened matrix promoted sprouting from endothelial cell(EC)spheroids and upregulated expressions of tip cell-enriched genes in vitro.Moreover,tip cells showed increased cellular stiffness,more actin cytoskeleton organization and enhanced YAP nuclear transfer than stalk and phalanx ECs.We further uncovered that substrate stiffness regulates FAK and Paxillin phosphorylation in focal adhesion of ECs promoting Rac1 transition from inactive to active state.YAP is subsequently activated and translocated into nucleus,leading to increased tip cell specification.p-Paxillin can also loosen the intercellular connection which also facilitates tip cell specification.Collectively our present study shows that matrix stiffness modulates tip cell formation through p-PXN-Rac1-YAP signaling axis,shedding light on the role of mechanotransduction in tip cell formation.This is of special significance in biomaterial design and treatment of some pathological situations.

关键词： Tip cells Mechanotransduction Stiffness Angiogenesis Extracellular matrix

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Efficacy of a mineralized collagen bone-grafting material for peri-implant bone defect reconstruction in mini pigs

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Regenerative Biomaterials 2019年第2期6卷 107-111页

作者： Enbo Wang Jianmin Han xuehui zhang Yuhan Wu Xu-Liang Deng Department of Oral and Maxillofacial Surgery Peking University School and Hospital of Stomatology22 Zhongguancun South StreetHaidian DistrictBeijing 100081China Department of Dental Materials Peking University School and Hospital of Stomatology22 Zhongguancun South StreetHaidian DistrictBeijing 100081China Department of Geriatric Dentistry Peking University School and Hospital of Stomatology22 Zhongguancun South StreetHaidian DistrictBeijing 100081China

The mechanism of the mineralization process induced by natural mineralized collagen(MC)has been investigated for decades.The purpose of this study was to investigate the efficacy of selfassembled MC for peri-implant bone defect reconstruction in a mini pig.A standardized peri-implant bone defect model was created using 14 mini pig mandibles.Two materials were evaluated,i.e.a mixture of hydroxyapatite and collagen(Type A,TA),and self-assembled MC(Type B,TB).Bio-Oss(BO)and untreated(blank control,BC)groups were used as controls.After 3-and 6-month healing periods,the mini pigs were sacrificed for histomorphometric and microcomputed tomography analysis.After 3 months of healing,the average alveolar ridge height was 3.2761.57mm for group TA,3.28±2.02mm for group TB and 3.37±1.09mm for group BO,while group BC showed the lowest height of 2.68±0.47mm.After 6 months of healing,the average alveolar ridge height was 2.64±1.13mm for group TA,4.31±1.80mm for group TB and 3.8761.38mm for group BO,while group BC showed the lowest height of 2.48±1.80mm.The experimental groups and control group showed similar bone volume density,bone complexity and histological reaction.The self-assembled MC(Type B)stimulated new bone formation in the reconstruction of deficient alveolar ridges around the dental implant;it also displayed excellent clinical operability compared with bone grafts without collagen.

关键词： dental implant bone-grafting material mineralized collagen

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多簧片结构的磁保持继电器多物理场刚柔耦合仿真模型建立和实验分析

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电工技术学报 2024年第10期39卷 3192-3205页

作者：赵靖英李宁张雪辉赵正元河北工业大学电气工程学院天津300401 河北工业大学省部共建电工装备可靠性与智能化国家重点实验室天津300401 西安铁路信号有限责任公司西安710010

多簧片结构的磁保持继电器衔铁转动引起的触点碰撞、弹跳现象使运动过程复杂,静、动态特性理论分析和仿真模型建立困难。以某型号多簧片结构的磁保持继电器为研究对象,理论分析结构拓扑及工作机理,考虑触点间切入深度,引入狄拉克函数和... 详细信息

多簧片结构的磁保持继电器衔铁转动引起的触点碰撞、弹跳现象使运动过程复杂,静、动态特性理论分析和仿真模型建立困难。以某型号多簧片结构的磁保持继电器为研究对象,理论分析结构拓扑及工作机理,考虑触点间切入深度,引入狄拉克函数和赫维赛德函数,解决簧片受力分散及触点由于碰撞、弹跳引起的作用力不连续问题;将簧片等效为悬臂梁,基于欧拉-伯努利梁理论建立触簧系统三簧片分段耦合动力学模型。利用Ansys Maxwell引入基于误差的自适应网格划分方法求解电磁机构静态特性;考虑触簧系统簧片运动变形效应,通过ADAMS基于模态理论,构建刚柔耦合动力学仿真模型。基于分段动力学思想,搭建电-磁-机械运动多物理场刚柔耦合仿真模型。利用高速摄像机、电流探头等设计磁保持继电器实验方案,搭建实验平台,测试并分析磁保持继电器触点吸合运动时间、触点压力、弹跳时间、线圈电流,并分析人工装配簧片引起触点压力不同使继电器动作过程存在的不一致性问题,验证该文所提多簧片结构的磁保持继电器特性分段耦合分析方法和多物理场刚柔耦合仿真模型的有效性。

关键词：磁保持继电器多簧片结构碰撞弹跳分段耦合动力学模型多物理场刚柔耦合

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