Osteogenesis imperfecta（OI） comprises a group of heritable connective tissue disorders generally defined by recurrent fractures, low bone mass, short stature and skeletal fragility. Beyond the skeletal complications...Osteogenesis imperfecta（OI） comprises a group of heritable connective tissue disorders generally defined by recurrent fractures, low bone mass, short stature and skeletal fragility. Beyond the skeletal complications of OI,many patients also report intolerance to physical activity, fatigue and muscle weakness. Indeed, recent studies have demonstrated that skeletal muscle is also negatively affected by OI, both directly and indirectly. Given the well-established interdependence of bone and skeletal muscle in both physiology and pathophysiology and the observations of skeletal muscle pathology in patients with OI, we investigated the therapeutic potential of simultaneous anabolic targeting of both bone and skeletal muscle using a soluble activin receptor 2B（ACVR2B） in a mouse model of type Ⅲ OI（oim）. Treatment of 12-week-old oim mice with ACVR2 B for 4 weeks resulted in significant increases in both bone and muscle that were similar to those observed in healthy,wild-type littermates. This proof of concept study provides encouraging evidence for a holistic approach to treating the deleterious consequences of OI in the musculoskeletal system.展开更多
A quantum chain model of multiple molecule motors is proposed as a mathematical physics theory for the microscopic modeling of classical force-velocity relation and tension transients in muscle fibers. The proposed mo...A quantum chain model of multiple molecule motors is proposed as a mathematical physics theory for the microscopic modeling of classical force-velocity relation and tension transients in muscle fibers. The proposed model was a quantum many-particle Hamiltonian to predict the force-velocity relation for the slow release of muscle fibers, which has not yet been empirically defined and was much more complicated than the hyperbolic relationships. Using the same Hamiltonian model, a mathematical force-velocity relationship was proposed to explain the tension observed when the muscle was stimulated with an alternative electric current. The discrepancy between input electric frequency and the muscle oscillation frequency could be explained physically by the Doppler effect in this quantum chain model. Further more, quantum physics phenomena were applied to explore the tension time course of cardiac muscle and insect flight muscle. Most of the experimental tension transient curves were found to correspond to the theoretical output of quantum two- and three-level models. Mathematical modeling electric stimulus as photons exciting a quantum three-level particle reproduced most of the tension transient curves of water bug Lethocerus maximus.展开更多
In this letter, a comparison between three types （two linear and one nonlinear） of models of skeletal muscle stiffness is shown. Results are compared with experimental data for biceps brachii in the case of muscle s...In this letter, a comparison between three types （two linear and one nonlinear） of models of skeletal muscle stiffness is shown. Results are compared with experimental data for biceps brachii in the case of muscle stretching and with the Hill equation for a biological muscle. It is shown that results for nonlinear stiffness model in case of length-force relationship fits to the experimental data.展开更多
Skeletal muscle is a dynamic tissue in which homeostasis and function are guaranteed by a very defined three-dimensional organization of myofibers in respect to other nonmuscular components,including the extracellular...Skeletal muscle is a dynamic tissue in which homeostasis and function are guaranteed by a very defined three-dimensional organization of myofibers in respect to other nonmuscular components,including the extracellular matrix and the nervous network.In particular,communication between myofibers and the nervous system is essential for the overall correct development and function of the skeletal muscle.A wide range of chronic,acute and genetic-based human pathologies that lead to the alteration of muscle function are associated with modified preservation of the fine interaction between motor neurons and myofibers at the neuromuscular junction.Recent advancements in the development of in vitro models for human skeletal muscle have shown that three-dimensionality and integration of multiple cell types are both key parameters required to unveil pathophysiological relevant phenotypes.Here,we describe recent achievement reached in skeletal muscle modeling which used biomaterials for the generation of three-dimensional constructs of myotubes integrated with motor neurons.展开更多
As the torso is critical to the coordinated movement and flexibility of vertebrates,a 6-(Degree of Freedom)DOF bionic parallel torso with noteworthy motion space was designed in our previous work.To improve the compli...As the torso is critical to the coordinated movement and flexibility of vertebrates,a 6-(Degree of Freedom)DOF bionic parallel torso with noteworthy motion space was designed in our previous work.To improve the compliance of the parallel mechanism,a pair of virtual muscle models is constructed on both sides of the rotating joints of each link of the mechanism,and a bionic muscle control algorithm is introduced.By analyzing the control parameters of the muscle model,dynamic characteristics similar to those of biological muscle are obtained.An adaptive stiffness control is proposed to adaptively adjust the stiffness coefficient with the change in the external load of the parallel mechanism.The attitude closed-loop control can effectively keep the attitude angle unchanged when the position of the moving platform changes.The simulations and experiments are undertaken to validate compliant movements and the flexibility and adaptability of the parallel mechanism.展开更多
Virtual reality(VR)technology revitalises rehabilitation training by creating rich,interactive virtual rehabilitation scenes and tasks that deeply engage patients.Robotics with immersive VR environments have the poten...Virtual reality(VR)technology revitalises rehabilitation training by creating rich,interactive virtual rehabilitation scenes and tasks that deeply engage patients.Robotics with immersive VR environments have the potential to significantly enhance the sense of immersion for patients during training.This paper proposes a rehabilitation robot system.The system integrates a VR environment,the exoskeleton entity,and research on rehabilitation assessment metrics derived from surface electromyographic signal(sEMG).Employing more realistic and engaging virtual stimuli,this method guides patients to actively participate,thereby enhancing the effectiveness of neural connection reconstruction—an essential aspect of rehabilitation.Furthermore,this study introduces a muscle activation model that merges linear and non-linear states of muscle,avoiding the impact of non-linear shape factors on model accuracy present in traditional models.A muscle strength assessment model based on optimised generalised regression(WOAGRNN)is also proposed,with a root mean square error of 0.017,347 and a mean absolute percentage error of 1.2461%,serving as critical assessment indicators for the effectiveness of rehabilitation.Finally,the system is preliminarily applied in human movement experiments,validating the practicality and potential effectiveness of VRcentred rehabilitation strategies in medical recovery.展开更多
Active muscle response is a key factor in the motion and injury of the human head and neck.Due to the limitations of experimentation and the shortcomings of previous finite element models,the influence of material par...Active muscle response is a key factor in the motion and injury of the human head and neck.Due to the limitations of experimentation and the shortcomings of previous finite element models,the influence of material parameters of cervical muscle on motions of the head and neck during a car crash have not been comprehensively investigated.In the present work,a model of the cervical muscle in a 50th-percentile adult male was constructed.The muscles were modelled using solid finite elements,with a nonlinear-elastic and viscoelastic material and a Hill material modelling the passive and active parts of each muscle,respectively.The head dynamic responses of the model were validated using results obtained from volunteer sled tests.The influence of the material parameters of a muscle on head and neck motions were determined.Our key finding was that the greater the stiffness and the contraction strength of the neck muscles,the smaller the rotation angle of the head and the neck,and,hence,the lower the risk of head and neck injury to occupants in a car crash.展开更多
Deformation of skin and muscle is essential for bringing an animated character to life. This deformation is difficult to animate in a realistic fashion using traditional techniques because of the subtlety of the skin ...Deformation of skin and muscle is essential for bringing an animated character to life. This deformation is difficult to animate in a realistic fashion using traditional techniques because of the subtlety of the skin deformations that must move appropriately for the character design. In this paper, we present an algorithm that generates natural, dynamic, and detailed skin deformation(movement and jiggle) from joint angle data sequences. The algorithm has two steps: identification of parameters for a quasi-static muscle deformation model, and simulation of skin deformation. In the identification step, we identify the model parameters using a musculoskeletal model and a short sequence of skin deformation data captured via a dense marker set. The simulation step first uses the quasi-static muscle deformation model to obtain the quasi-static muscle shape at each frame of the given motion sequence(slow jump). Dynamic skin deformation is then computed by simulating the passive muscle and soft tissue dynamics modeled as a mass–spring–damper system. Having obtained the model parameters, we can simulate dynamic skin deformations for subjects with similar body types from new motion data. We demonstrate our method by creating skin deformations for muscle co-contraction and external impacts from four different behaviors captured as skeletal motion capture data. Experimental results show that the simulated skin deformations are quantitatively and qualitatively similar to measured actual skin deformations.展开更多
A non-equilibrium statistical method is used to study the collective characteristics of myosin II motors in a sarcomere during its contraction. By means of Fokker-Planck equation of molecular motors, we present a dyna...A non-equilibrium statistical method is used to study the collective characteristics of myosin II motors in a sarcomere during its contraction. By means of Fokker-Planck equation of molecular motors, we present a dynamic mechanical model for the sarcomere in skeletal muscle. This model has been solved with a numerical algorithm based on experimental chemical transition rates. The influences of ATP concentration and load on probability density, contraction velocity and maximum active force are discussed respectively. It is shown that contraction velocity and maximum isometric active force increase with the increasing ATP concentration and become constant when the ATP concentration reaches equilibrium saturation. Contraction velocity reduces gradually as the load force increases. We also find that active force begins to increase then decrease with the increasing length of sarcomere, and has a maximum value at the optimal length that all myosin motors can attach to actin filament. Our results are in good agreement with the Hill muscle model.展开更多
Fatigue is believed to be a major contributory factor to occupational injuries in machine operators.The development of accurate and usable techniques to measure operator fatigue is therefore important.In this study,we...Fatigue is believed to be a major contributory factor to occupational injuries in machine operators.The development of accurate and usable techniques to measure operator fatigue is therefore important.In this study,we used a novel method based on surface electromyography (sEMG) of the biceps brachii and the Borg scale to evaluate local muscle fatigue in the upper limb after isometric muscle action.Thirteen young males performed isometric actions with the upper limb at different force levels.sEMG activities of the biceps brachii were recorded during the actions.Borg scales were used to evaluate the subjective sensation of local fatigue of the biceps brachii after the actions.sEMG activities were analyzed using the one-third band octave method,and an equation to determine the degree of fatigue was derived based on the relationship between the variable and the Borg scale.The results showed that the relationship could be expressed by a conic curve,and could be used to evaluate muscle fatigue during machine operation.展开更多
基金supported by NIAMS,of the National Institutes of Health,under award numbers R01AR062074 (to DJD) and R01AR060636 (to S-JL)the Harry Headley Charitable and Research Foundation,Punta Gorda,FL(to ELG-L)
文摘Osteogenesis imperfecta（OI） comprises a group of heritable connective tissue disorders generally defined by recurrent fractures, low bone mass, short stature and skeletal fragility. Beyond the skeletal complications of OI,many patients also report intolerance to physical activity, fatigue and muscle weakness. Indeed, recent studies have demonstrated that skeletal muscle is also negatively affected by OI, both directly and indirectly. Given the well-established interdependence of bone and skeletal muscle in both physiology and pathophysiology and the observations of skeletal muscle pathology in patients with OI, we investigated the therapeutic potential of simultaneous anabolic targeting of both bone and skeletal muscle using a soluble activin receptor 2B（ACVR2B） in a mouse model of type Ⅲ OI（oim）. Treatment of 12-week-old oim mice with ACVR2 B for 4 weeks resulted in significant increases in both bone and muscle that were similar to those observed in healthy,wild-type littermates. This proof of concept study provides encouraging evidence for a holistic approach to treating the deleterious consequences of OI in the musculoskeletal system.
基金Project supported by the Fundamental Research Foundation for the Central Universities of China
文摘A quantum chain model of multiple molecule motors is proposed as a mathematical physics theory for the microscopic modeling of classical force-velocity relation and tension transients in muscle fibers. The proposed model was a quantum many-particle Hamiltonian to predict the force-velocity relation for the slow release of muscle fibers, which has not yet been empirically defined and was much more complicated than the hyperbolic relationships. Using the same Hamiltonian model, a mathematical force-velocity relationship was proposed to explain the tension observed when the muscle was stimulated with an alternative electric current. The discrepancy between input electric frequency and the muscle oscillation frequency could be explained physically by the Doppler effect in this quantum chain model. Further more, quantum physics phenomena were applied to explore the tension time course of cardiac muscle and insect flight muscle. Most of the experimental tension transient curves were found to correspond to the theoretical output of quantum two- and three-level models. Mathematical modeling electric stimulus as photons exciting a quantum three-level particle reproduced most of the tension transient curves of water bug Lethocerus maximus.
基金supported by"Master Programme"of the Foundation for Polish Science
文摘In this letter, a comparison between three types （two linear and one nonlinear） of models of skeletal muscle stiffness is shown. Results are compared with experimental data for biceps brachii in the case of muscle stretching and with the Hill equation for a biological muscle. It is shown that results for nonlinear stiffness model in case of length-force relationship fits to the experimental data.
基金supported by IRP Consolidator Grant 2021(Grant Code:21/05 Irp),Fondazione Cittàdella Speranza,Italy(to AU)。
文摘Skeletal muscle is a dynamic tissue in which homeostasis and function are guaranteed by a very defined three-dimensional organization of myofibers in respect to other nonmuscular components,including the extracellular matrix and the nervous network.In particular,communication between myofibers and the nervous system is essential for the overall correct development and function of the skeletal muscle.A wide range of chronic,acute and genetic-based human pathologies that lead to the alteration of muscle function are associated with modified preservation of the fine interaction between motor neurons and myofibers at the neuromuscular junction.Recent advancements in the development of in vitro models for human skeletal muscle have shown that three-dimensionality and integration of multiple cell types are both key parameters required to unveil pathophysiological relevant phenotypes.Here,we describe recent achievement reached in skeletal muscle modeling which used biomaterials for the generation of three-dimensional constructs of myotubes integrated with motor neurons.
基金the National Natural Science Foundation of China(Grant No.51605039)the Open Foundation of Shanghai Collaborative Innovation Center of Intelligent Manufacturing Robot Technology for Large Components,in part by the China Postdoctoral Science Foundation(Grant No.2018T111005)the Fundamental Research Funds for the Central Universities(Grant Nos.300102259308,300102259401,and 300102252503).
文摘As the torso is critical to the coordinated movement and flexibility of vertebrates,a 6-(Degree of Freedom)DOF bionic parallel torso with noteworthy motion space was designed in our previous work.To improve the compliance of the parallel mechanism,a pair of virtual muscle models is constructed on both sides of the rotating joints of each link of the mechanism,and a bionic muscle control algorithm is introduced.By analyzing the control parameters of the muscle model,dynamic characteristics similar to those of biological muscle are obtained.An adaptive stiffness control is proposed to adaptively adjust the stiffness coefficient with the change in the external load of the parallel mechanism.The attitude closed-loop control can effectively keep the attitude angle unchanged when the position of the moving platform changes.The simulations and experiments are undertaken to validate compliant movements and the flexibility and adaptability of the parallel mechanism.
基金National Key Research and Development Program of China,Grant/Award Number:2022YFB4700701National Outstanding Youth Science Fund Project of National Natural Science Foundation of China,Grant/Award Number:52025054。
文摘Virtual reality(VR)technology revitalises rehabilitation training by creating rich,interactive virtual rehabilitation scenes and tasks that deeply engage patients.Robotics with immersive VR environments have the potential to significantly enhance the sense of immersion for patients during training.This paper proposes a rehabilitation robot system.The system integrates a VR environment,the exoskeleton entity,and research on rehabilitation assessment metrics derived from surface electromyographic signal(sEMG).Employing more realistic and engaging virtual stimuli,this method guides patients to actively participate,thereby enhancing the effectiveness of neural connection reconstruction—an essential aspect of rehabilitation.Furthermore,this study introduces a muscle activation model that merges linear and non-linear states of muscle,avoiding the impact of non-linear shape factors on model accuracy present in traditional models.A muscle strength assessment model based on optimised generalised regression(WOAGRNN)is also proposed,with a root mean square error of 0.017,347 and a mean absolute percentage error of 1.2461%,serving as critical assessment indicators for the effectiveness of rehabilitation.Finally,the system is preliminarily applied in human movement experiments,validating the practicality and potential effectiveness of VRcentred rehabilitation strategies in medical recovery.
基金supported by the National Natural Science Foundation of China (51205117)Natural Science Foundation of Hunan Province (2019JJ70045)Hunan Province Education Department Science Research Project (19C1559).
文摘Active muscle response is a key factor in the motion and injury of the human head and neck.Due to the limitations of experimentation and the shortcomings of previous finite element models,the influence of material parameters of cervical muscle on motions of the head and neck during a car crash have not been comprehensively investigated.In the present work,a model of the cervical muscle in a 50th-percentile adult male was constructed.The muscles were modelled using solid finite elements,with a nonlinear-elastic and viscoelastic material and a Hill material modelling the passive and active parts of each muscle,respectively.The head dynamic responses of the model were validated using results obtained from volunteer sled tests.The influence of the material parameters of a muscle on head and neck motions were determined.Our key finding was that the greater the stiffness and the contraction strength of the neck muscles,the smaller the rotation angle of the head and the neck,and,hence,the lower the risk of head and neck injury to occupants in a car crash.
文摘Deformation of skin and muscle is essential for bringing an animated character to life. This deformation is difficult to animate in a realistic fashion using traditional techniques because of the subtlety of the skin deformations that must move appropriately for the character design. In this paper, we present an algorithm that generates natural, dynamic, and detailed skin deformation(movement and jiggle) from joint angle data sequences. The algorithm has two steps: identification of parameters for a quasi-static muscle deformation model, and simulation of skin deformation. In the identification step, we identify the model parameters using a musculoskeletal model and a short sequence of skin deformation data captured via a dense marker set. The simulation step first uses the quasi-static muscle deformation model to obtain the quasi-static muscle shape at each frame of the given motion sequence(slow jump). Dynamic skin deformation is then computed by simulating the passive muscle and soft tissue dynamics modeled as a mass–spring–damper system. Having obtained the model parameters, we can simulate dynamic skin deformations for subjects with similar body types from new motion data. We demonstrate our method by creating skin deformations for muscle co-contraction and external impacts from four different behaviors captured as skeletal motion capture data. Experimental results show that the simulated skin deformations are quantitatively and qualitatively similar to measured actual skin deformations.
基金supported by the National Natural Science Foundation of China (Grant No. 61075101/60643002)the Research Fund of State Key Laboratory of MSV, China (Grant No. MSV-2010-1)+2 种基金the National High-Tech Research and Development Program of China (Grant No. 2006AA04Z240)the Shanghai Dawn Program (Grant No. 07SG14)the Medical and Technology Intercrossing Research Foundation of Shanghai Jiao Tong University (Grant No. YG2010ZD101)
文摘A non-equilibrium statistical method is used to study the collective characteristics of myosin II motors in a sarcomere during its contraction. By means of Fokker-Planck equation of molecular motors, we present a dynamic mechanical model for the sarcomere in skeletal muscle. This model has been solved with a numerical algorithm based on experimental chemical transition rates. The influences of ATP concentration and load on probability density, contraction velocity and maximum active force are discussed respectively. It is shown that contraction velocity and maximum isometric active force increase with the increasing ATP concentration and become constant when the ATP concentration reaches equilibrium saturation. Contraction velocity reduces gradually as the load force increases. We also find that active force begins to increase then decrease with the increasing length of sarcomere, and has a maximum value at the optimal length that all myosin motors can attach to actin filament. Our results are in good agreement with the Hill muscle model.
文摘Fatigue is believed to be a major contributory factor to occupational injuries in machine operators.The development of accurate and usable techniques to measure operator fatigue is therefore important.In this study,we used a novel method based on surface electromyography (sEMG) of the biceps brachii and the Borg scale to evaluate local muscle fatigue in the upper limb after isometric muscle action.Thirteen young males performed isometric actions with the upper limb at different force levels.sEMG activities of the biceps brachii were recorded during the actions.Borg scales were used to evaluate the subjective sensation of local fatigue of the biceps brachii after the actions.sEMG activities were analyzed using the one-third band octave method,and an equation to determine the degree of fatigue was derived based on the relationship between the variable and the Borg scale.The results showed that the relationship could be expressed by a conic curve,and could be used to evaluate muscle fatigue during machine operation.
