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Functionalized carbon dots for corrosion protection:Recent advances and future perspectives

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International Journal of Minerals,Metallurgy and Materials 2023年第11期30卷 2112-2133页

作者： Li Zhao Jinke Wang Kai Chen Jingzhi Yang Xin Guo Hongchang Qian Lingwei Ma Dawei Zhang Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China National Materials Corrosion and Protection Data Center University of Science and Technology BeijingBeijing 100083China key laboratory of biomechanics and mechanobiology(Beihang University) Ministry of EducationBeijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringBeihang UniversityBeijing 100083China

Metal corrosion causes significant economic losses,safety issues,and environmental pollution.Hence,its prevention is of immense research interest.Carbon dots(CDs)are a new class of zero-dimensional carbon nanomaterials,which have been considered for corrosion protection applications in recent years due to their corrosion inhibition effect,fluorescence,low toxicity,facile chemical modification,and cost-effectiveness.This study provides a comprehensive overview of the synthesis,physical and chemical properties,and anticorrosion mechanisms of functionalized CDs.First,the corrosion inhibition performance of different types of CDs is introduced,followed by discussion on their application in the development of smart protective coatings with self-healing and/or self-reporting properties.The effective barrier formed by CDs in the coatings can inhibit the spread of local damage and achieve self-healing behavior.In addition,diverse functional groups on CDs can interact with Fe^(3+)and H^(+)ions generated during the corrosion process;this interaction changes their fluorescence,thereby demonstrating self-reporting behavior.Moreover,challenges and prospects for the development of CD-based corrosion protection systems are also presented.

关键词： carbon dots corrosion protection corrosion inhibitors self-healing self-reporting

Electrospinning of a sandwich-structured membrane with sustained release capability and long-term anti-inflammatory effects for dental pulp regeneration

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Bio-Design and Manufacturing 2022年第2期5卷 305-317页

作者： Fenghe Yang Jiangxue Wang Xiaoyu Li Zhenzhen Jia Qiang Wang Dazhi Yu Jinyu Li Xufeng Niu key laboratory for biomechanics and mechanobiology of ministry of education Beijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringBeihang UniversityBeijing 100083China Department of Burn Plastic Surgery 80th Army Hospital of PLAWeifang 261021China Department of Hand Surgery 971st Army Hospital of PLAQingdao 266000China Department of Orthopaedics Dongzhimen HospitalBeijing University of Chinese MedicineBeijing 100700China

Current electro spun membranes used for pulp capping still lack the sustained-release capability and long-term anti-inflammatory effects that are favorable for dental pulp regeneration.In this work,a single-layered poly(lac tic acid)(PLA)electro spun membrane loaded with amorphous calcium phosphate(ACP)and aspirin(PLA/ACP/Aspirin membrane,i.e.,PA A membrane)is sandwiched between two poly(lactic-co-glycolic acid)(PLGA)electro spun membranes as a novel sandwich-structured PLGA and PA A composite electro spun membrane(PLGA-PAA membrane)to resolve the need for sustained-release design and anti-inflammatory effects.Contact angle measurements indicate that the PLGA-PAA membrane is more hydrophilic than the PAA membrane.An in vitro release study reveals that PLGA membranes coated on PAA membrane could slightly slow down ion release,while signiificantly prolonging aspirin release.We also co-cultured membranes with dental pulp stem cells(DPSCs)and human monocytic THP-1 cells to evaluate their osteogenic ability and anti-inflammatory effects,respectively.Compared with the PAA membrane,the PLGA-PAA membrane promotes cell adhesion,proliferation,and osteogenic differentiation.A prolonged anti-inflammatory effect of up to 18 days is also observed in the PLGA-PAA group.The results suggest a promising strategy for fabricating an electro spun membrane system with controlled release capabilities and long-term anti-inflammatory effects for use as pulp-capping material for regeneration of the dentin-pulp complex.

关键词： Electrospinning Sandwich-structured Pulp capping Controlled release Anti-inflammatory effects

Friction behaviour between a laparoscopic grasper and the large intestine during minimally invasive surgery

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Biosurface and Biotribology 2022年第1期8卷 58-68页

作者： Yan Guo Chengmo Cai Wei Li key laboratory for Advanced Technology of Materials of ministry of education Tribology Research InstituteSouthwest Jiaotong UniversityChengduChina

Slippage is a common phenomenon between laparoscopic graspers and tissues during minimally invasive surgery,which may lead to inefficient surgical operations,prolonged operation time,and increased patient suffering.The stability factors related to the friction behaviour between laparoscopic graspers and the large intestine,including bio-surface liquids,pulling angle,and surface profile of graspers,were studied.The friction behav-iour at the large intestine-grasper interface was tested using a UMT-II tribometer under the conditions of clamping force of 1-4 N,sliding displacement of 15 mm,and sliding velocity of 2 mm/s to simulate the grasping and pulling operations of soft tissue.The results showed that the bio-surface liquid(serum)of the large intestine significantly decreased the friction coefficient,thus reducing the grasping efficiency.A pulling angle of 15°could generate the peak frictional force and enhance the grasping stability.The frictional force increased with the ratio of the profile surface area of the grasper.These results demonstrate that the grasping stability can be improved by changing either the bio-surface liquid condition or the pulling angle.In addition,a grasper with a larger profile surface area can also prevent slippage due to its significant influence on the pressure distribution and actual contact area for tissue retention.

关键词： biointerface biomaterials biomechanics biotribology wear mechanism

Ultrasound speed and attenuation in progressive trypsin digested articular cartilage

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Science China(Life Sciences) 2011年第11期54卷 1029-1035页

作者： NIU HaiJun LI LiFeng SUN Feng YAN Yan WANG YueXiang LI DeYu FAN YuBo State key laboratory of Software Development Environment Key Laboratory of Ministry of Education for Biomechanics and Mechanobiology School of Biological Science and Medical Engineering Beihang University Beijing 100191 China Department of Ultrasound People＇s Liberation Army General Hospital Beijing 100085 China

Subtle changes of articular cartilage(AC) can lead to tissue degeneration and even osteoarthritis(OA).The early degeneration of AC is closely related to a change in proteoglycans(PG) content.The observation of PG is therefore an appropriate way of studying OA and evaluating the degree of AC degeneration.In this study,20 cartilage-bone samples were prepared from normal porcine femoral condyle cartilage and 10 samples were digested over 2 h using 0.25% trypsin solution.The dynamic process of PG-digestion was explored using a conventional A-mode ultrasound(US) experimental system with a 10 MHz center frequency.Quantitative acoustic parameters were calculated from ultrasonic radio-frequency echo signals and included US speed(USS),US amplitude attenuation coefficient(UAA) and broadband US attenuation coefficient(BUA).The experimental results showed that the conventional A-mode ultrasound is valuable for tracking the degree of PG-digestion.Histology also confirmed the validity of the ultrasound observations.For every AC sample,the degree of PG-digestion within a given time was different and was affected by individual differences.After two hours of degeneration,USS showed a mean decrease of 0.4%(P<0.05).UAA was significantly lower after a two-hour PG depletion period(from(2.45±0.23) to(2.28±0.41) dB mm?1).BUA showed no significant differences during this process.In conclusion,conventional ultrasound can provide useful information about trypsin-induced progressive PG depletion in AC and can reflect variations of PG content via the quantitative acoustic parameters USS and UAA.The results of this study may be used to identify an indirect indicator of cartilage matrix integrity and OA disease progression.

关键词：振幅衰减系数超声速度关节软骨胰蛋白酶消化交流采样样品制备实验系统

In vitro and in vivo evaluation of micro-alloyed magnesium for potential application in alveolar bone fixation screws

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Journal of Materials Science & Technology 2023年第13期144卷 62-69页

作者： Hongyan Tang Qing Li Min Li Xuenan Gu Chengkung Cheng Yubo Fan key laboratory of biomechanics and mechanobiology(Beihang University) Ministry of EducationBeijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringBeihang UniversityBeijing 100083China Center of Digital Dentistry Peking University School and Hospital of StomatologyBeijing 100081China National Engineering Research Center of Oral Biomaterials and Digital Medical Devices Beijing 100081China School of Biomedical Engineering Shanghai Jiao Tong UniversityShanghai 200030China

Alveolar bone augmentation with fixation screws has difficulties such as non-degradable materials that could lead to secondary surgery and insufficient osseointegration due to the subgingival environment in dental practice.With degradability and a high degree of osteogenesis,Mg alloy is a successful biodegrad-able material for orthopedic applications,and its application in dentistry has made certain progress.How-ever,considering the unique subgingival healing properties of oral implants,there is still a gap between the desired material properties for clinical applications and available materials.Indeed,studies on the use of Mg-based fixation screws for dentistry applications are still rare.In this study,we reported a magnesium alloy with low combined addition of strontium and lanthanum.The mechanical properties,degradation behavior,osteogenesis,and gingival compatibility were systematically investigated for assess-ing its potential application in alveolar bone fixation screws.With the alloying element content restricted to 0.3 wt.%,Mg-Sr-La alloy still exhibited good mechanical properties,with yield tensile and compressive strength twice higher than those of pure Mg.The in vitro degradation rate of this alloy was 0.10 mm y-1,which was slightly slower than high-purity Mg.The indirect and direct cell assay confirmed the elevated osteoblastic differentiation of MC3T3-E1 and migration of HGF-1 cells.Moreover,Mg-Sr-La alloy demon-strated a relatively slow degradation in the maxillary bone of Beagles.A remarkable promotion of the bone-implant contacts and significantly decreased fibrous encapsulation was observed in the subgingival environment,implying superior osseointegration of the experimental alloy than the titanium control.The empirical findings here reveal the great potential of Mg-Sr-La alloy for the application in alveolar bone fixation devices.

关键词： Magnesium alloys Alveolar ridge augmentation Fixation screws Osseointegration

Biomechanism of impact resistance in the woodpecker's head and its application

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Science China(Life Sciences) 2013年第8期56卷 715-719页

作者： WANG LiZhen LU Shan LIU XiaoYu NIU XuFeng WANG Chao NI YiKun ZHAO MeiYa FENG ChengLong ZHANG Ming FAN YuBo key laboratory for biomechanics and mechanobiology of ministry of education School of Biological Science and Medical EngineeringBeihang University Science China Press Interdisciplinary Division of Biomedical Engineering the Hong Kong Polytechnic University

The woodpecker does not suffer head/eye impact injuries while drumming on a tree trunk with high acceleration(more than 1000×g) and high frequency.The mechanism that protects the woodpecker's head has aroused the interest of ornithologists,biologists and scientists in the areas of mechanical engineering,material science and electronics engineering.This article reviews the literature on the biomechanisms and materials responsible for protecting the woodpecker from head impact injury and their applications in engineering and human protection.

关键词：应用工程啄木鸟耐冲击性运动性材料科学高加速度机械工程生物学家

Transcranial direct current stimulation inhibits epileptic activity propagation in a large-scale brain network model

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Science China(Technological Sciences) 2023年第12期66卷 3628-3638页

作者： YU Ying FAN YuBo HAN Fang LUAN GuoMing WANG QingYun School of Engineering Medicine Beihang UniversityBeijing 100191China Beihang University Beijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringKey Laboratory Biomechanics&MechanobiologyMinistry of EducationBeijing 100191China College of Information Science and Technology Donghua UniversityShanghai 201620China Beijing key laboratory of Epilepsy Sanbo Brain HospitalCapital Medical UniversityBeijing 100069China Department of Dynamics and Control Beihang UniversityBeijing 100191China Beijing Institute of Brain Disorders Capital Medical UniversityBeijing 100069China

Transcranial direct current stimulation(tDCS)is a noninvasive technique that uses constant,low-intensity direct current to regulate brain activities.Clinical studies have shown that cathode-tDCS(c-tDCS)is effective in reducing seizure frequency in patients with epilepsy.Due to the heterogeneity and patient specificity of seizures,patient-specific epilepsy networks are increasingly important in exploring the regulatory role of c-tDCS.In this study,we first set the left hippocampus,parahippocampus,and amygdala as the epileptogenic zone(EZ),and the left inferior temporal cortex and ventral temporal cortex as the initial propagation zone(PZ)to establish a large-scale epilepsy network model.Then we set tDCS cathode locations according to the maximum average energy of the simulated EEG signals and systematically study c-tDCS inhibitory effects on the propagation of epileptic activity.The results show that c-tDCS is effective in suppressing the propagation of epileptic activity.Further,to consider the patient specificity,we set specific EZ and PZ according to the clinical diagnosis of 6 patients and establish patient-specific epileptic networks.We find that c-tDCS can suppress the propagation of abnormal activity in most patient-specific epileptic networks.However,when the PZ is widely distributed in both hemispheres,the treatment effect of c-tDCS is not satisfactory.Hence,we propose dual-cathode tDCS.For epilepsy models with a wide distribution of PZ,it can inhibit the propagation of epileptiform activity in other nodes except EZ and PZ without increasing the tDCS current strength.Our results provide theoretical support for the treatment of epilepsy with tDCS.

关键词： epilepsy large-scale brain network modeling transcranial direct current stimulation neural mass model

Effect of 3D anchorage attachment on the alleviating tipping/extrusion of premolars for en-mass distalization of maxillary molars with clear aligners:A finite element study

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Medicine in Novel Technology and Devices 2023年第2期18卷 272-280页

作者： Lurong Jia Chunjuan Wang Yao He Chao Wang Antonio Apicella Jinlin Song Yubo Fan Chongqing key laboratory of Oral Diseases and Biomedical Sciences ChongqingChina Stomatological Hospital of Chongqing Medical University ChongqingChina key laboratory of biomechanics and mechanobiology Ministry of EducationBeijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringSchool of Engineering MedicineBeihang UniversityBeijingChina Chongqing Municipal key laboratory of Oral Biomedical Engineering of Higher education ChongqingChina Polytechnique School of Engineering and Base Science University of CampaniaItaly

This study aimed to explore the optimal invisible orthodontic force system during the en-mass distalization of two maxillary molars to minimize the side effect of anchorage loss by changing the direction of the application of the orthodontic force system.A high bio-fidelity 3D finite element model including maxilla,periodontal ligament,dentition,clear aligner,3D anchorage attachment and mini-implant was established.Different lengths of lateral hooks of 3D-printed anchorage attachments and mini-implant positions into the palatal alveolus were considered.A 200 g distal force was applied to the lateral hooks of different horizontal lengths(3.26 mm,6.52 mm and 9.78 mm)with the mini-implant as the application point.Using ABAQUS software,orthodontic tooth movements under 12 different clinical treatment designs were analyzed and calculated.The 3D anchorage attachment enhanced the anchorage of anterior teeth and alleviated the tipping/extrusion of premolars.In contrast to without clear aligners,length of the lateral hook had a negligible effect on both mesial tipping and buccal tipping with clear aligners,which could then be ignored.The change in mesial tipping was less and nearly remained constant despite of the different heights of the mini-implant.The 3D anchorage attachment assisted clear aligner can avoid the side effects of anterior tooth proclination caused by insufficient anchorage.The length of the lateral hook,and height of the mini-implant in this invisible orthodontic force system hardly affects the tooth movement of anchorage units.Clear aligners can effectively control the rotation and tipping of anchorage units caused by 3D anchorage attachment.

关键词： Clear aligner Orthodontics 3D printing Three-dimensional finite element Attachments Reinforced anchorage

Simulation and prediction of membrane fusion dynamics

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Theoretical & Applied Mechanics Letters 2022年第1期12卷 49-55页

作者： Zhi Zheng Shouqin Lü Mian Long Center of biomechanics and Bioengineering Key Laboratory of Microgravity(National Microgravity Laboratory)Beijing Key Laboratory of Engineered Construction and Mechanobiologyand CAS Center for Excellence in Complex System MechanicsInstitute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Membrane fusion is an important process by which biological membranes perform their life activities. Simulations show that the membrane fusion process happens mainly through three pathways, where the Stalk-Pore hypothesis, in which two membranes come into close contact to form a stalk to a hemifusion intermediate, and then the fusion pore opens to achieve completely fusion, is widely accepted, and there exist two free energy barriers that break the current structural steady state for lipid rearrangement. Factors of lipid composition, mechanical environment, protein and ion have regulatory roles in the membrane fusion process by effecting membrane curvature structurally and the free energy barriers from energetic perspective. Meanwhile, many theoretical models, represented by the Helfrich model, have been proposed to predict the membrane fusion process. In this paper, we review the research process of membrane fusion and mainly introduce the dynamics of membrane fusion, regulation factors and typical theoretical models.

关键词： Membrane fusion Hemifusion intermediates Fusion pathway Regulation Helfrich model