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Effects of delayed repair of peripheral nerve injury on the spatial distribution of motor endplates in target muscle

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Neural Regeneration Research 2022年第2期17卷 459-464页

作者： Dong-Dong Li Jin Deng Bo Jin Shuai Han Xin-Yi Gu Xue-feng Zhou Xiao-Feng Yin Department of Trauma and Orthopedics Peking University People’s HospitalBeijingChina Department of Orthopedics PLA Strategic Support Force Medical CenterBeijingChina

Motor endplates(MEPs) are important sites of information exchange between motor neurons and skeletal muscle, and are distributed in an organized pattern of lamellae in the muscle. Delayed repair of peripheral nerve injury typically results in unsatisfactory functional recovery because of MEP degeneration. In this study, the mouse tibial nerve was transected and repaired with a biodegradable chitin conduit, immediately following or 1 or 3 months after the injury. Fluorescent α-bungarotoxin was injected to label MEPs. Tissue optical clearing combined with light-sheet microscopy revealed that MEPs were distributed in an organized pattern of lamellae in skeletal muscle after delayed repair for 1 and 3 months. However, the total number of MEPs, the number of MEPs per lamellar cluster, and the maturation of single MEPs in gastrocnemius muscle gradually decreased with increasing denervation time. These findings suggest that delayed repair can restore the spatial distribution of MEPs, but it has an adverse effect on the homogeneity of MEPs in the lamellar clusters and the total number of MEPs in the target muscle. The study procedures were approved by the Animal Ethics Committee of the Peking University People's Hospital(approval No. 2019 PHC015) on April 8, 2019.

关键词： degeneration delayed repair lamellar cluster light-sheet microscopy motor endplates peripheral nerve injury three-dimensional distribution tissue optical clearing

Footholds optimization for legged robots walking on complex terrain

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机械工程前沿:英文版 2023年第2期18卷 99-114页

作者： Yunpeng yin Yue ZHAO Yuguang xiao feng GAO State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China AI Institute School of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

This paper proposes a novel continuous footholds optimization method for legged robots to expand their walking ability on complex terrains.The algorithm can efficiently run onboard and online by using terrain perception information to protect the robot against slipping or tripping on the edge of obstacles,and to improve its stability and safety when walking on complex terrain.By relying on the depth camera installed on the robot and obtaining the terrain heightmap,the algorithm converts the discrete grid heightmap into a continuous costmap.Then,it constructs an optimization function combined with the robot’s state information to select the next footholds and generate the motion trajectory to control the robot’s locomotion.Compared with most existing footholds selection algorithms that rely on discrete enumeration search,as far as we know,the proposed algorithm is the first to use a continuous optimization method.We successfully implemented the algorithm on a hexapod robot,and verified its feasibility in a walking experiment on a complex terrain.

关键词： footholds optimization legged robot complex terrain adapting hexapod robot locomotion control

Temporal changes in the spinal cord transcriptome after peripheral nerve injury

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Neural Regeneration Research 2020年第7期15卷 1360-1367页

作者： Jian Weng Dong-Dong Li Bao-Guo Jiang Xiao-Feng Yin Department of Orthopedics and Trauma Peking University People's HospitalBeijingChina Department of Bone&Joint Surgery Peking University Shenzhen HospitalShenzhenGuangdong ProvinceChina Department of Surgery the 517th Hospital of the People's Liberation ArmyXinzhouShanxi ProvinceChina

Peripheral nerve injury may trigger changes in mRNA levels in the spinal cord.Finding key mRNAs is important for improving repair after nerve injury.This study aimed to investigate changes in mRNAs in the spinal cord following sciatic nerve injury by transcriptomic analysis.The left sciatic nerve denervation model was established in C57 BL/6 mice.The left L4–6 spinal cord segment was obtained at 0,1,2,4 and 8 weeks after severing the sciatic nerve.mRNA expression profiles were generated by RNA sequencing.The sequencing results of spinal cord mRNA at 1,2,4,and 8 weeks after severing the sciatic nerve were compared with those at 0 weeks by bioinformatic analysis.We identified 1915 differentially expressed mRNAs in the spinal cord,of which 4,1909,and 2 were differentially expressed at 1,4,and 8 weeks after sciatic nerve injury,respectively.Sequencing results indicated that the number of differentially expressed mRNAs in the spinal cord was highest at 4 weeks after sciatic nerve injury.These mRNAs were associated with the cellular response to lipid,ATP metabolism,energy coupled proton transmembrane transport,nuclear transcription factor complex,vacuolar proton-transporting V-type ATPase complex,inner mitochondrial membrane protein complex,tau protein binding,NADH dehydrogenase activity and hydrogen ion transmembrane transporter activity.Of these mRNAs,Sgk1,Neurturin and Gpnmb took part in cell growth and development.Pathway analysis showed that these mRNAs were mainly involved in aldosterone-regulated sodium reabsorption,oxidative phosphorylation and collecting duct acid secretion.Functional assessment indicated that these mRNAs were associated with inflammation and cell morphology development.Our findings show that the number and type of spinal cord mRNAs involved in changes at different time points after peripheral nerve injury were different.The number of differentially expressed mRNAs in the spinal cord was highest at 4 weeks after sciatic nerve injury.These results provide reference data for finding new targets

关键词： deep sequencing expression profile gene therapy mRNAs nerve regeneration peripheral nerve injury RNA sequencing sciatic nerve injury spinal cord transcriptome

Smart Gait:A Gait Optimization Framework for Hexapod Robots

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 146-159页

作者： Yunpeng yin feng Gao Qiao Sun Yue Zhao Yuguang xiao State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Lenovo Corporation ShanghaiChina AI Institute School of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

The current gait planning for legged robots is mostly based on human presets,which cannot match the flexible characteristics of natural mammals.This paper proposes a gait optimization framework for hexapod robots called Smart Gait.Smart Gait contains three modules:swing leg trajectory optimization,gait period&duty optimization,and gait sequence optimization.The full dynamics of a single leg,and the centroid dynamics of the overall robot are considered in the respective modules.The Smart Gait not only helps the robot to decrease the energy consumption when in locomotion,mostly,it enables the hexapod robot to determine its gait pattern transitions based on its current state,instead of repeating the formalistic clock-set step cycles.Our Smart Gait framework allows the hexapod robot to behave nimbly as a living animal when in 3D movements for the first time.The Smart Gait framework combines offline and online optimizations without any fussy data-driven training procedures,and it can run efficiently on board in real-time after deployment.Various experiments are carried out on the hexapod robot LittleStrong.The results show that the energy consumption is reduced by 15.9%when in locomotion.Adaptive gait patterns can be generated spontaneously both in regular and challenge environments,and when facing external interferences.

关键词： Gait optimization Swing trajectory optimization Legged robot Hexapod robot

The anatomical,electrophysiological and histological observations of muscle contraction units in rabbits:a new perspective on nerve injury and regeneration

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Neural Regeneration Research 2022年第1期17卷 228-232页

作者： Ting-Min Xu Bo Chen Zong-Xue Jin Xiao-Feng Yin Pei-Xun Zhang Bao-Guo Jiang Department of Trauma and Orthopedics Peking University People’s HospitalBeijingChina Key Laboratory of Trauma and Neural Regeneration(Peking University) Ministry of EducationBeijingChina Trauma Center Peking University People’s HospitalBeijingChina National Trauma Medical Center BeijingChina Department of Rehabilitation Peking University People’s HospitalBeijingChina

In the conventional view a muscle is composed of intermediate structures before its further division into microscopic muscle fibers.Our experiments in mice have confirmed this intermediate structure is composed of the lamella cluster formed by motor endplates,the innervating nerve branches and the corresponding muscle fibers,which can be viewed as an independent structural and functional unit.In this study,we verified the presence of these muscle construction units in rabbits.The results showed that the muscular branch of the femoral nerve sent out 4–6 nerve branches into the quadriceps and the tibial nerve sent out 4–7 nerve branches into the gastrocnemius.When each nerve branch of the femoral nerve was stimulated from the most lateral to the medial,the contraction of the lateral muscle,intermediate muscle and medial muscle of the quadriceps could be induced by electrically stimulating at least one nerve branch.When stimulating each nerve branch of the tibial nerve from the lateral to the medial,the muscle contraction of the lateral muscle 1,lateral muscle 2,lateral muscle 3 and medial muscle of the gastrocnemius could be induced by electrically stimulating at least one nerve branch.Electrical stimulation of each nerve branch resulted in different electromyographical waves recorded in different muscle subgroups.Hematoxylin-eosin staining showed most of the nerve branches around the neuromuscular junctions consisted of one individual neural tract,a few consisted of two or more neural tracts.The muscles of the lower limb in the rabbit can be subdivided into different muscle subgroups,each innervated by different nerve branches,thereby allowing much more complex muscle activities than traditionally stated.Together,the nerve branches and the innervated muscle subgroups can be viewed as an independent structural and functional unit.This study was approved by the Animal Ethics Committee of Peking University People’s Hospital(approval No.2019 PHE027)on October 20,2019.

关键词： anatomy electrophysiology femoral nerve hematoxylin-eosin staining gastrocnemius motor endplate muscle contraction unit peripheral nerve quadriceps rabbit skeletal muscle tibial nerve

Electrophoretic deposition of hybrid organic-inorganic PTFE/Al/CuO energetic film

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Defence Technology（防务技术） 2023年第4期22卷 112-118页

作者： Yan-jun yin feng Hu Le-hua Cheng xiao-dong Wang School of Chemistry and Material Engineering Chaohu UniversityChaohu238000China

Thermite films are typical energetic materials(EMs)and have great value in initiating explosive devices.However,research in thermite film preparation is far behind that of research in thermite powders.Electrophoretic deposition(EPD)is an emerging,rapid coating method for film fabrication,including of energetic composite films.In this work,a polytetrafluoroethylene(PTFE)/Al/CuO organic-inorganic hybrid energetic film was successfully obtained using the above method for the first time.The addition of lithocholic acid as a surfactant into the electroplating suspension enabled PTFE to be charged.The combustion and energy release were analyzed by means of a high-speed camera and differential scanning calorimetery(DSC).It was found that the combustion process and energy release of PTFE/Al/CuO were much better than that of Al/CuO.The main reason for the excellent combustion performance of the hybrid PTFE/Al/CuO system was that the oxidability of PTFE accelerated the redox reaction between Al and CuO.The prepared PTFE/Al/CuO film was also employed as ignition material to fire a B-KNO_3 explosive successfully,indicating considerable potential for use as an ignition material in micro-ignitors.This study sheds light on the preparation of fluoropolymer-containing organic-inorganic hybrid energetic films by one-step electrophoretic deposition.

关键词： Energetic film Electrophoretic deposition Fluorine-based polymers Combustion performance Thermite

Estimation of non-point source pollution loads with flux method in Danjiangkou Reservoir area,China

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Water Science and Engineering 2017年第2期10卷 134-142页

作者： xiao-kang Xin Wei yin Ke-feng Li State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Changjiang Water Resources Protection Institute Changjiang Water Resources Commission

The estimation of non-point source pollution loads into the Danjiangkou Reservoir is highly significant to environmental protection in the watershed. In order to overcome the drawbacks of traditional watershed numerical models, a base flow separation method was established coupled with a digital filtering method and a flux method. The digital filtering method has been used to separate the base flows of the Hanjiang,Tianhe, Duhe, Danjiang, Laoguan, and Qihe rivers. Based on daily discharge, base flow, and pollutant concentration data, the flux method was used to calculate the point source pollution load and non-point source pollution load. The results show that:(1) In the year 2013, the total inflow of the six rivers mentioned above accounted for 95.9% of the total inflow to the Danjiangkou Reservoir. The total pollution loads of chemical oxygen demand(CODMn) and total phosphorus(TP) from the six rivers were 58.20 103 t and 1.863 10~3 t, respectively, and the non-point source pollution loads were 39.82 10~3 t and 1.544 10~3 t, respectively, indicating that the non-point source pollution is a major factor(with a contribution rate of 68.4% for CODMnand 82.9% for TP).(2) The Hanjiang River is the most significant contributor of pollution loads to the Danjiangkou Reservoir, and its CODMnand TP contribution rates reached 79.3% and 83.2%, respectively. The Duhe River took the second place.(3) Non-point source pollution mainly occurred in the wet season in 2013, accounting for 80.8% and 90.9% of the total pollution loads of CODMnand TP, respectively. It is concluded that the emphasis of pollution control should be placed on non-point source pollution.

关键词： Danjiangkou Reservoir Non-point source pollution Base flow separation Digital filtering method (DFM) Flux method

Identification of four differentially expressed genes associated with acute and chronic spinal cord injury based on bioinformatics data

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Neural Regeneration Research 2021年第5期16卷 865-870页

作者： Su-Ping Niu Ya-Jun Zhang Na Han Xiao-Feng Yin Dian-ying Zhang Yu-Hui Kou Key Laboratory of Trauma and Neural Regeneration(Peking University) Ministry of EducationBeijingChina Department of Trauma and Orthopedics Peking University People’s HospitalBeijingChina Trauma Medicine Center Peking University People’s HospitalBeijingChina Office of Academic Research Peking University People’s HospitalBeijingChina

Complex pathological changes occur during the development of spinal cord injury(SCI),and determining the underlying molecular events that occur during SCI is necessary for the development of promising molecular targets and therapeutic strategies.This study was designed to explore differentially expressed genes(DEGs)associated with the acute and chronic stages of SCI using bioinformatics analysis.Gene expression profiles(GSE45006,GSE93249,and GSE45550)were downloaded from the Gene Expression Omnibus database.SCI-associated DEGs from rat samples were identified,and Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed.In addition,a protein-protein interaction network was constructed.Approximately 66 DEGs were identified in GSE45550 between 3–14 days after SCI,whereas 2418 DEGs were identified in GSE450061–56 days after SCI.Moreover,1263,195,and 75 overlapping DEGs were identified between these two expression profiles,3,7/8,and 14 days after SCI,respectively.Additionally,16 overlapping DEGs were obtained in GSE450061–14 days after SCI,including Pank1,Hn1,Tmem150c,Rgd1309676,Lpl,Mdh1,Nnt,Loc100912219,Large1,Baiap2,Slc24a2,Fundc2,Mrps14,Slc16a7,Obfc1,and Alpk3.Importantly,3882 overlapping DEGs were identified in GSE932491–6 months after SCI,including 3316 protein-coding genes and 567 long non-coding RNA genes.A comparative analysis between GSE93249 and GSE45006 resulted in the enrichment of 1135 overlapping DEGs.The significant functions of these 1135 genes were correlated with the response to the immune effector process,the innate immune response,and cytokine production.Moreover,the biological processes and KEGG pathways of the overlapping DEGs were significantly enriched in immune system-related pathways,osteoclast differentiation,the nuclear factor-κB signaling pathway,and the chemokine signaling pathway.Finally,an analysis of the overlapping DEGs associated with both acute and chronic SCI,assessed using the expression profiles GSE93249 and GSE45006,identified four

关键词： bioinformatics differential expression factor gene immune response injury pathways protein spinal cord

Effect of titanium and rare earth microalloying on microsegregation,eutectic carbides of M2 high speed steel during ESR process

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Journal of Rare Earths 2020年第9期38卷 1030-1038,I0005页

作者： Fuxing yin Lu Wang Zhixia xiao Jianhang feng Lin Zhao School of Materials Science and Engineering Hebei University of TechnologyTianjin 300130China Research Institute for Energy Equipment Materials Hebei University of TechnologyTianjin 300130China Tianjin Key Laboratory of Materials Laminating Fabrication and Interfacial Controlling Technology Tianjin 300130China Central Iron and Steel Research Institute Beijing 100081China

The effects of RE and Ti microalloying during electroslag remelting(ESR)process on the microsegregation and morphology of eutectic M2C carbides in M2 high speed steel were investigated.The results show that the addition of 0.2 wt%RE can alleviate the segregation of C,W,Mo,V and Cr,while the morphology of eutectic M2C carbides hardly changes.The microalloying with the addition of 0.5 wt%Ti has the lowest degree of microsegregation due to the improvement of primary dendrites by the effective heterogeneous nucleating agent of(Ti,V)(C,N)particles.The addition of Ti makes the mo rphology of M2C carbides change from rod-like or maze-like shape into a coarse feathery shape,exhibiting anisotropic facet growth characteristics.For the microalloying of 0.2 wt%RE and 0.5 wt%Ti,the segregation of the main metal alloying elements is slightly more severe than that of the addition of only RE or Ti.Under the combined action of RE and Ti,the feathery eutectic M2C becomes thinner and shorter and tends to be isolated or distributed in a discontinuous network.

关键词： Microsegregation Morphology Eutectic carbides High speed steel Electroslag remelting Rare earths