The twisted and coiled polymer(TCP)artificial muscles driven by hydraulic pressure offer high mechanical efficiency and power density.The relation between geometry,mechanics,and actuation performance for this kind of ...The twisted and coiled polymer(TCP)artificial muscles driven by hydraulic pressure offer high mechanical efficiency and power density.The relation between geometry,mechanics,and actuation performance for this kind of muscle is crucial.In this study,we study the mechanics and actuation characteristics of TCP tube-based muscles driven by hydraulic pressure through experiment,theory,and finite element simulation.Accounting for the helical geometry and transverse isotropy of the TCP muscles,we develop a phenomenological model to predict the actuation performance of TCP tube-based muscles.The torsional and tensile actuation characteristics of the twisted and TCP tube-based muscle driven by hydraulic pressure are characterized.It is found that the cold drawing enhances the anisotropy of the polyvinyl chloride tube,resulting in an improved actuation performance of the twisted and TCP muscles.The torsional actuation in the twisted tube reaches the maximum at a critical bias angle for a given pressure,while the tensile actuation in TCP muscles increases with the coil diameter.The theoretical predictions and simulations are in good agreement with experimental results.This study is significant for guiding the design of TCP tube-based muscles and achieving their precise actuation control.展开更多
An effective and rapid response of muscle contraction and relaxation is crucial for performing appropriate body gaits,including movements of the arms and legs.Any deformation in the muscles can disrupt gait stability,...An effective and rapid response of muscle contraction and relaxation is crucial for performing appropriate body gaits,including movements of the arms and legs.Any deformation in the muscles can disrupt gait stability,making muscle movement difficult.The arm,consisting of the radius,ulna,and humerus,can be modeled as mechanically jointed pendulums,with tensions from the arm muscles varying during contraction and relaxation.In a static state,the muscles maintain constant tension and length,even when external gravitational force is applied to the hand.This study presents a system in which a pair of jointed pendulums is driven by artificial muscles,represented by flexible ropes wound around the edge of an electronic motor's wheel.Muscle movement is simulated through the adjustment of the length of the flexible ropes attached to the motor.Switching between the clockwise and counterclockwise rotation of the motor modifies the length of the flexible ropes,thereby altering the intrinsic tensions to control arm movements.Electrical signals from a simple neural circuit are used to control the rotation of the electronic motor,enabling the regulation of muscle movement in the arm model by adjustable flexible ropes.The stability criterion for the electromechanical arm is derived,and the interactions among the neural circuit,electronic motor,and jointed pendulums are examined in detail.The results and proposed scheme can contribute to the design of controllable artificial arms,providing potential assistance to disabled arms by incorporating auxiliary artificial muscles.展开更多
AIM:To investigate the difference of medial rectus(MR)and lateral rectus(LR)between acute acquired concomitant esotropia(AACE)and the healthy controls(HCs)detected by magnetic resonance imaging(MRI).METHODS:A case-con...AIM:To investigate the difference of medial rectus(MR)and lateral rectus(LR)between acute acquired concomitant esotropia(AACE)and the healthy controls(HCs)detected by magnetic resonance imaging(MRI).METHODS:A case-control study.Eighteen subjects with AACE and eighteen HCs were enrolled.MRI scanning data were conducted in target-controlled central gaze with a 3-Tesla magnetic resonance scanner.Extraocular muscles(EOMs)were scanned in contiguous image planes 2-mm thick spanning the EOM origins to the globe equator.To form posterior partial volumes(PPVs),the LR and MR cross-sections in the image planes 8,10,12,and 14 mm posterior to the globe were summed and multiplied by the 2-mm slice thickness.The data were classified according to the right eye,left eye,dominant eye,and non-dominant eye,and the differences in mean cross-sectional area,maximum cross-sectional area,and PPVs of the MR and LR muscle in the AACE group and HCs group were compared under the above classifications respectively.RESULTS:There were no significant differences between the two groups of demographic characteristics.The mean cross-sectional area of the LR muscle was significantly greater in the AACE group than that in the HCs group in the non-dominant eyes(P=0.028).The maximum cross-sectional area of the LR muscle both in the dominant and non-dominant eye of the AACE group was significantly greater than the HCs group(P=0.009,P=0.016).For the dominant eye,the PPVs of the LR muscle were significantly greater in the AACE than that in the HCs group(P=0.013),but not in the MR muscle(P=0.698).CONCLUSION:The size and volume of muscles dominant eyes of AACE subjects change significantly to overcome binocular diplopia.The LR muscle become larger to compensate for the enhanced convergence in the AACE.展开更多
How the state of living muscles modulates the features of nonlinear elastic waves generated by external dynamic loads remains unclear because of the challenge of directly observing and modeling nonlinear elastic waves...How the state of living muscles modulates the features of nonlinear elastic waves generated by external dynamic loads remains unclear because of the challenge of directly observing and modeling nonlinear elastic waves in skeletal muscles in vivo,considering their active deformation behavior.Here,this important issue is addressed by combining experiments performed with an ultrafast ultrasound imaging system to track nonlinear shear waves(shear shock waves)in muscles in vivo and finite element analysis relying on a physically motivated constitutive model to study the effect of muscle activation level.Skeletal muscle was loaded with a deep muscle stimulator to generate shear shock waves(SSWs).The particle velocities,second and third harmonics,and group velocities of the SSWs in living muscles under both passive and active states were measured in vivo.Our experimental results reveal,for the first time,that muscle states have a pronounced effect on wave features;a low level of activation may facilitate the occurrence of both the second and third harmonics,whereas a high level of activation may inhibit the third harmonic.Finite element analysis was further carried out to quantitatively explore the effect of active muscle deformation behavior on the generation and propagation of SSWs.The simulation results at different muscle activation levels confirmed the experimental findings.The ability to reveal the effects of muscle state on the features of SSWs may be helpful in elucidating the unique dynamic deformation mechanism of living skeletal muscles,quantitatively characterizing diverse shock wave-based therapy instruments,and guiding the design of muscle-mimicking soft materials.展开更多
Coordinated contraction of skeletal muscles relies on selective connections between the muscles and multiple classes of the spinal motoneuro ns.Howeve r,current research on the spatial location of the spinal motoneuro...Coordinated contraction of skeletal muscles relies on selective connections between the muscles and multiple classes of the spinal motoneuro ns.Howeve r,current research on the spatial location of the spinal motoneurons innervating differe nt muscles is limited.In this study,we investigated the spatial distribution and relative position of different motoneurons that control the deep muscles of the mouse hindlimbs,which were innervated by the obturator nerve,femoral nerve,inferior gluteal nerve,deep pe roneal nerve,and tibial nerve.Locations were visualized by combining a multiplex retrograde tracking technique compatible with three-dimensional imaging of solvent-cleared o rgans(3DISCO)and 3-D imaging technology based on lightsheet fluorescence microscopy(LSFM).Additionally,we propose the hypothesis that"messenger zones"exist as interlaced areas between the motoneuron pools that dominate the synergistic or antagonist muscle groups.We hypothesize that these interlaced neurons may participate in muscle coordination as messenger neurons.Analysis revealed the precise mutual positional relationships among the many motoneurons that innervate different deep muscles of the mouse.Not only do these findings update and supplement our knowledge regarding the overall spatial layout of spinal motoneurons that control mouse limb muscles,but they also provide insights into the mechanisms through which muscle activity is coordinated and the architecture of motor circuits.展开更多
In the intricate skeletal muscle tissue,the symbiotic relationship between myotubes and their supporting vasculature is pivotal in delivering essential oxygen and nutrients.This study explored the complex interplay be...In the intricate skeletal muscle tissue,the symbiotic relationship between myotubes and their supporting vasculature is pivotal in delivering essential oxygen and nutrients.This study explored the complex interplay between skeletal muscle and endothelial cells in the vascularization ofmuscle tissue.By harnessing the capabilities of three-dimensional(3D)bioprinting and modeling,we developed a novel approach involving the co-construction of endothelial and muscle cells,followed by their subsequent differentiation.Our findings highlight the importance of the interaction dynamics between these two cell types.Notably,introducing endothelial cells during the advanced phases of muscle differentiation enhanced myotube assembly.Moreover,it stimulated the development of the vascular network,paving the way for the early stages of vascularized skeletal muscle development.The methodology proposed in this study indicates the potential for constructing large-scale,physiologically aligned skeletal muscle.Additionally,it highlights the need for exploring the delicate equilibrium and mutual interactions between muscle and endothelial cells.Based on the multicell-type interaction model,we can predict promising pathways for constructing even more intricate tissues or organs.展开更多
Objective:To evaluate the effects of Catalpa bignonioides fruit extract on the promotion of muscle growth and muscular capacity in vitro and in vivo.Methods:Cell viability was measured using the 3-(4,5-dimethylthiazol...Objective:To evaluate the effects of Catalpa bignonioides fruit extract on the promotion of muscle growth and muscular capacity in vitro and in vivo.Methods:Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.Cell proliferation was assessed using a 5-bromo-2’-deoxyuridine(BrdU)assay kit.Western blot analysis was performed to determine the protein expressions of related factors.The effects of Catalpa bignonioides extract were investigated in mice using the treadmill exhaustion test and whole-limb grip strength assay.Chemical composition analysis was performed using high-performance liquid chromatography(HPLC).Results:Catalpa bignonioides extract increased the proliferation of C2C12 mouse myoblasts by activating the Akt/mTOR signaling pathway.It also induced metabolic changes,increasing the number of mitochondria and glucose metabolism by phosphorylating adenosine monophosphate-activated protein kinase.In an in vivo study,the extract-treated mice showed improved motor abilities,such as muscular endurance and grip strength.Additionally,HPLC analysis showed that vanillic acid may be the main component of the Catalpa bignonioides extract that enhanced muscle strength.Conclusions:Catalpa bignonioides improves exercise performance through regulation of growth and metabolism in skeletal muscles,suggesting its potential as an effective natural agent for improving muscular strength.展开更多
[Objective] This study aimed to investigate the characteristics of deposition of inosine monophosphate （IMP） and intramuscular fat （IMF） in muscles of Jinghai yellow chickens and its crossbred.[Method] The charact...[Objective] This study aimed to investigate the characteristics of deposition of inosine monophosphate （IMP） and intramuscular fat （IMF） in muscles of Jinghai yellow chickens and its crossbred.[Method] The characteristics of IMP and IMF deposition of 112-day-old Jinghai yellow chickens （J×J） and its two different 70-day- old crossbreeds （J×B and B×B） were analyzed. The IMP content in breast muscle and leg muscle were determined by HPLC. [Result] The contents of IMP and cor- rected inosine monophosphate （IMPc） in breast muscle were significantly or ex- tremely significantly higher than that in leg muscle of the chickens in the three groups whether in male or female chickens （P〈0.05 or P〈0.01）. There were no sig- nificant difference in the contents of IMP and IMPc between hens and roosters （P〉 0.05）. The fresh degree of breast muscle and leg muscle was 96,11%-98.16% and 87.22%-93.07%, respectively. And the fresh degree of breast muscle was higher than that of leg muscle. In the three groups, the IMF content in leg muscle was significantly higher than that in breast muscle whether in male or female chickens （P〈0.05）. The contents of IMF in breast muscle and leg muscle were 0.36%-0.75% and 1.84%-2.38%, respectively. The iMP content in breast muscle of chickens in Bx J group was extremely significantly higher than that in breast muscle of chickens in JxJ group （P〈0.01）, but the contents of IMPc and iMF of breast muscle and leg muscle of the chickens in the three groups had no significant difference （P〉0.05）. [Conclusion] To sum up, the freshness and flavor significantly differ between the breast muscle and leg muscle of chickens, but show no significant difference among the three groups.展开更多
Objective:To provide new insights for the evaluation and diagnosis of chronic neck pain(CNP).Methods:22 patients with CNP and 22 healthy individuals were recruited from South China Normal University,who were all colle...Objective:To provide new insights for the evaluation and diagnosis of chronic neck pain(CNP).Methods:22 patients with CNP and 22 healthy individuals were recruited from South China Normal University,who were all college students.The subjects'neck extensor muscle strength in the head neutral position,the natural anteversion position,and the maximum forward flexion position were measured by an isometric muscle strength tester respectively.The neck extensor strength of CNP patients and healthy subjects were compared.Results:In the neutral position,the maximum isometric muscle strength of neck extensor muscles was 12.31 kg for CNP patients and 15.16 kg for healthy individuals,resulting in a ratio of 81%strength in patients compared to healthy subjects.This difference was highly significant(P<0.000).In the natural anteversion position,the respective values were 12.6 kg for CNP patients and 15.05 kg for healthy individuals,with a ratio of 83%,and a significant difference between groups(P<0.001).In the maximum forward flexion position of the head,the values were 13.36 kg for CNP patients and 16.15 kg for healthy individuals,with a ratio of 82%,and a highly significant difference(P<0.000).Conclusion:The neck extensor muscle strength levels in college students with CNP were significantly lower compared to healthy college students across all measured positions.展开更多
[Objective] This study aimed to explore the effects of IGFs system on the growth of goose skeletal muscles. [Method] Quantitative fluorescence PCR technique was adopted to study the variety- and gender-specificity in ...[Objective] This study aimed to explore the effects of IGFs system on the growth of goose skeletal muscles. [Method] Quantitative fluorescence PCR technique was adopted to study the variety- and gender-specificity in the expression of GHR, IGF-I, IGF-IR and IGFBP-3 genes in leg muscles of 70-day-old Taihu goose and Wanxi white goose, and the correlation between their expression and carcass traits was also investigated. [Resull] There was no variety difference in the expression of GHR, IGF-t, IGF-IR and IGFBP-3 genes in leg muscles of Taihu goose and Wanxi white goose, but there were significant variety differences in the body weight and leg muscle weight. There were no gender difference in the body weight, leg muscle weight and the rate of leg muscles; except IGF-I mRNA level that was significantly higher in male Taihu goose than in female ones（P=0.032）, there was no gender dif- ference in the expression of other three genes. Among the four tested genes, only IGFBP-3 mRNA exhibited an extremely significantly positively correlation with the rate of leg muscles, suggesting that IGFs may play a role in regulating the growth of leg muscles via IGFBP-3 system in 70-day-old goose. [Conclusion] This study provides theoretical basis for research in the skeletal growth and development.展开更多
Summary: The operation methods, clinical classification, postoperative function exercise of gluteal muscles contracture were investigated. Clinically and retrospectively, treatment of 1280 patients with gluteal muscle...Summary: The operation methods, clinical classification, postoperative function exercise of gluteal muscles contracture were investigated. Clinically and retrospectively, treatment of 1280 patients with gluteal muscles contracture, being subjected to a 'Z-shaped' release lengthening operation and efficiency exercise, was clearly standardized. All the cases were followed up from 3 months to 2 years with the effective rate being 100 %, the cure rate being 98. 5 %, the recent complications being 5%, and the far complications being 0. 2 %. It was concluded that the clear diagnosis combined with standarized operation and efficiency functional exercise could greatly improve the therapeutic effects of gluteal muscles contracture.展开更多
Developing artificial muscles that can replace biological muscles to accomplish various tasks iswhat we have long been aiming for.Recent advances in flexible materials and 3D printing technology greatly promote the de...Developing artificial muscles that can replace biological muscles to accomplish various tasks iswhat we have long been aiming for.Recent advances in flexible materials and 3D printing technology greatly promote the development of artificial muscle technology.A variety of flexible material-based artificial muscles that are driven by different external stimuli,including pressure,voltage,light,magnetism,temperature,etc.,have been developed.Among these,fluid-driven artificial muscles(FAMs),which can convert the power of fluid(gas or liquid)into the force output and displacement of flexible materials,are the most widely used actuation methods for industrial robots,medical instruments,and human-assisted devices due to their simplicity,excellent safety,large actuation force,high energy efficiency,and low cost.Herein,the bio-design,manufacturing,sensing,control,and applications of FAMs are introduced,including conventional pneumatic/hydraulic artificial muscles and several innovative artificial muscles driven by functional fluids.What’s more,the challenges and future directions of FAMs are discussed.展开更多
BACKGROUND De-afferentation or non-weight bearing induces rapid cortical and spinalα-motor neuron excitability.Author supposed that an end-effector type gait robot(EEGR)could provide patients with a training conditio...BACKGROUND De-afferentation or non-weight bearing induces rapid cortical and spinalα-motor neuron excitability.Author supposed that an end-effector type gait robot(EEGR)could provide patients with a training condition that was specific enough to activate rapid cortical/spinal neuroplasticity,leading to immediate muscle strengthening.The electromyographic and biomechanical comparisons were conducted.AIM To compare the electromyographic activities of the thigh and shank muscles and isometric peak torque(PT)before and after walking training on a floor or in the end-effector gait robot.METHODS Twelve outpatients without ambulatory dysfunction were recruited.Order of two interventions(5-min training on a floor at a comfortable pace or training in an EEGR with non-weight bearing on their feet and 100%guidance force at 2.1 km/h)were randomly chosen.Isometric PT,maximal ratio of torque development,amplitude of compound motor action potential(CMAP),and area under the curve(AUC)were evaluated before and 10 min after both interventions.RESULTS The degree of PT improvement of the dominant knee flexors was larger in the EEGR than on the floor(9.6±22.4 Nm/BW,P<0.01).The EEGR-trained patients had greater PT improvement of the dominant knee extensors than those who trained on the floor(4.5±28.1 Nm/BW,P<0.01).However,all electromyographic activities of the thigh and shank muscles(peak CMAP,mean and peak AUC)were significantly lower for the use of the EEGR than walking on the floor.CONCLUSION Immediate strengthening of the knee flexors and extensors was induced after the 5-min EEGR training,despite reduced muscular use.展开更多
According to the deficiency of the present model of pneumatic artificialmuscles (PAM), a serial model is built up based on the PAM's essential working principle with theelastic theory, it is validated by the quasi...According to the deficiency of the present model of pneumatic artificialmuscles (PAM), a serial model is built up based on the PAM's essential working principle with theelastic theory, it is validated by the quasi-static and dynamic experiment results, which are gainedfrom two experiment systems. The experiment results and the simulation results illustrate that theserial model has made a great success compared with Chou's model, which can describe the forcecharacteristics of PAM more precisely. A compensation item considering the braid's elasticity andthe coulomb damp is attached to the serial model based on the analysis of the experiment results.The dynamic experiment proves that the viscous damp of the PAM could be ignored in order to simplifythe model of PAM. Finally, an improved serial model of PAM is obtained.展开更多
Artificial yarn muscles show great potential in applications requiring low-energy consumption while maintaining high performance. However, conventional designs have been limited by weak ion-yarn muscle interactions an...Artificial yarn muscles show great potential in applications requiring low-energy consumption while maintaining high performance. However, conventional designs have been limited by weak ion-yarn muscle interactions and inefficient “rocking-chair” ion migration. To address these limitations, we present an electrochemical artificial yarn muscle design driven by a dual-ion co-regulation system. By utilizing two reaction channels, this system shortens ion migration pathways, leading to faster and more efficient actuation. During the charging/discharging process, PF_6~- ions react with carbon nanotube yarn, while Li~+ ions react with an Al foil. The intercalation reaction between PF_6~- and collapsed carbon nanotubes allows the yarn muscle to achieve an energy-free high-tension catch state. The dual-ion coordinated yarn muscles exhibit superior contractile stroke, maximum contractile rate, and maximum power densities, exceeding those of “rocking-chair” type ion migration yarn muscles. The dual-ion co-regulation system enhances the ion migration rate during actuation, resulting in improved performance. Moreover, the yarn muscles can withstand high levels of isometric stress, displaying a stress of 61 times that of skeletal muscles and 8 times that of “rocking-chair” type yarn muscles at higher frequencies. This technology holds significant potential for various applications, including prosthetics and robotics.展开更多
An exoskeleton force feedback dataglove is developed, which uses the pneumatic artificial muscles as actuators. On the basis of the simplified hand model, the motion equation is deduced according to the theory of Dena...An exoskeleton force feedback dataglove is developed, which uses the pneumatic artificial muscles as actuators. On the basis of the simplified hand model, the motion equation is deduced according to the theory of Denavit-Hartenberg. The model of the equivalent contact forces exerted by the object on the finger is proposed. By the principle of virtual work, the static equilibrium of finger is established. The force Jacobian matrix of finger is calculated, and then the joint torques of the finger when grasping objects are obtained. The theory and structure of the force feedback datagolve are introduced. Based on the theory of motion stabilization of four-bar linkage, the flexion angles of joints are measured. The torques on finger joints caused by the output forces of pneumatic artificial muscles are calculated. The output forces of pneumatic artificial muscle, whose values are controlled by its inner pressure, can be calculated by the joint torques of the finger when grasping objects. The arms of force, driving torques and the needed output forces of pneumatic muscle are calculated for each joint of the index finger. The criterion of output force of pneumatic muscle is given.展开更多
The purpose of this study was to show the benefit of visualizing a tree-dimensional (3D) image of the tongue’s muscle structure, which until now has been regarded as fully understood. Until now, no suitable 3D observ...The purpose of this study was to show the benefit of visualizing a tree-dimensional (3D) image of the tongue’s muscle structure, which until now has been regarded as fully understood. Until now, no suitable 3D observation methods have been developed for soft tissue, such as the tongue, using?histological magnification. For this purpose, this study used a micro-computed tomographic method (micro-CT) and image processing after the fixation, decalcification, and dehydration of a mouse tongue. Results: 3D rendered images of tongue muscles obtained by micro-CT showed every muscle and their relationships to each other. The superior longitudinal and the hyoglossus muscles of the tongue made up one group, while the inferior longitudinal and the styloglossus muscles of the tongue made up another. The boundary of the two muscles in each group was difficult to distinguish. On the other hand, what appear to be newly described muscles were identified. These results indicate that our micro-CT method is beneficial and that classical knowledge of tongue muscles derived from two-dimensional (2D) images does not fully describe the actual complexity of the tongue muscles. In our opinion, 3D rendered images mixed with raw structure can provide a more in-depth picture of the tongue from an integrated as well as an analytical perspective.展开更多
This study aimed to clarify the immediate effect that trunk muscle exercise has on muscle reaction time, and to clarify the effect of 2-week exercise on muscle reaction time. The study showed that as for immediate eff...This study aimed to clarify the immediate effect that trunk muscle exercise has on muscle reaction time, and to clarify the effect of 2-week exercise on muscle reaction time. The study showed that as for immediate effects, the muscle reaction time was significantly shortened in the TrA/OI (transversus abdominis muscle/obliquus internus muscle) of two exercise groups. However, the immediate effect seen before the 2-week trunk muscle exercise intervention disappeared after the intervention. In addition, trunk muscle exercise intervention for 2 weeks significantly shortened the muscle reaction time of TrA/OI in one exercise group. Furthermore, shortening of the muscle reaction time was also observed in the MF (multifidus muscle) of both exercise groups. The factors affecting the muscle reaction time of TrA observed in this study were considered to be an improvement of neuromuscular function by the central nervous system. It was also considered that 2-week exercise intervention has a lower value after 2 weeks due to an improvement of neuromuscular function by the central nervous system, and an immediate effect could not be obtained with the same exercise as at the time of intervention.展开更多
Myasthenia gravis (MG) is an autoimmune disorder involving the neuromuscular junction that frequently affects the extra-ocular muscles (EOMs). It has been described as a very rare cause of bilateral EOM atrophy, but h...Myasthenia gravis (MG) is an autoimmune disorder involving the neuromuscular junction that frequently affects the extra-ocular muscles (EOMs). It has been described as a very rare cause of bilateral EOM atrophy, but histological analysis of such cases is lacking. A 66-year-old man presented with two months of right eyelid drooping and vertical diplopia. Examination showed bilateral ophthalmoparesis and complete right ptosis. The remainder of his exam was normal, and an MRI showed small EOMs. Acetylcholine receptor antibodies were elevated, establishing the diagnosis of MG. Oral corticosteroids and pyridostigmine followed by azathioprine improved his ptosis, but not his ophthalmoparesis. One year later he had surgical correction of his diplopia, and the resected superior rectus muscle showed complete replacement of EOM by connective tissue. MG can rarely cause bilateral EOM atrophy, which is characterized histologically by fibrosis in the muscle itself. Atrophy in the EOMs of a myasthenic patient may indicate a poor response to medical management alone.展开更多
The effects of 2-[p-(Dimethylamino)styryl] pyridine methiodide(DSPM)on slow response action potential(SRAP)and slow inward current(Isi) of guinea pig papillary muscles were studied by intracellular microelectrodes and...The effects of 2-[p-(Dimethylamino)styryl] pyridine methiodide(DSPM)on slow response action potential(SRAP)and slow inward current(Isi) of guinea pig papillary muscles were studied by intracellular microelectrodes and voltage clamp techniques.The APA and V_(max) of SRAP induced by high K￣+were decreased after 50 min of perfusion with DSPM solu- tion. Isi was suppressed from a peak value of8.8± 1.6μA to 5.7± 1.8μA, The results indicated that DSPM has a selective blocking effect on calcium channel.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12272146)the Fundamental Research Funds for the Central Universities(Grant No.2024BRA009)the National Ten Thousand Talent Program for Young Top-notch Talents。
文摘The twisted and coiled polymer(TCP)artificial muscles driven by hydraulic pressure offer high mechanical efficiency and power density.The relation between geometry,mechanics,and actuation performance for this kind of muscle is crucial.In this study,we study the mechanics and actuation characteristics of TCP tube-based muscles driven by hydraulic pressure through experiment,theory,and finite element simulation.Accounting for the helical geometry and transverse isotropy of the TCP muscles,we develop a phenomenological model to predict the actuation performance of TCP tube-based muscles.The torsional and tensile actuation characteristics of the twisted and TCP tube-based muscle driven by hydraulic pressure are characterized.It is found that the cold drawing enhances the anisotropy of the polyvinyl chloride tube,resulting in an improved actuation performance of the twisted and TCP muscles.The torsional actuation in the twisted tube reaches the maximum at a critical bias angle for a given pressure,while the tensile actuation in TCP muscles increases with the coil diameter.The theoretical predictions and simulations are in good agreement with experimental results.This study is significant for guiding the design of TCP tube-based muscles and achieving their precise actuation control.
基金supported by the National Natural Science Foundation of China(Grant Nos.62361037,12072139)。
文摘An effective and rapid response of muscle contraction and relaxation is crucial for performing appropriate body gaits,including movements of the arms and legs.Any deformation in the muscles can disrupt gait stability,making muscle movement difficult.The arm,consisting of the radius,ulna,and humerus,can be modeled as mechanically jointed pendulums,with tensions from the arm muscles varying during contraction and relaxation.In a static state,the muscles maintain constant tension and length,even when external gravitational force is applied to the hand.This study presents a system in which a pair of jointed pendulums is driven by artificial muscles,represented by flexible ropes wound around the edge of an electronic motor's wheel.Muscle movement is simulated through the adjustment of the length of the flexible ropes attached to the motor.Switching between the clockwise and counterclockwise rotation of the motor modifies the length of the flexible ropes,thereby altering the intrinsic tensions to control arm movements.Electrical signals from a simple neural circuit are used to control the rotation of the electronic motor,enabling the regulation of muscle movement in the arm model by adjustable flexible ropes.The stability criterion for the electromechanical arm is derived,and the interactions among the neural circuit,electronic motor,and jointed pendulums are examined in detail.The results and proposed scheme can contribute to the design of controllable artificial arms,providing potential assistance to disabled arms by incorporating auxiliary artificial muscles.
基金Supported by National Natural Science Foundation of China(No.82070998)Young Scientists Fund of the National Natural Science Foundation of China(No.82101174)+3 种基金Program of Beijing Hospitals Authority(No.XMLX202103)Program of Beijing Municipal Science&Technology Commission(No.Z201100005520044)Capital Health Development Research Special Project(No.2022-1-2053)Beijing Hospitals Authority Youth Programme(No.QML20230205).
文摘AIM:To investigate the difference of medial rectus(MR)and lateral rectus(LR)between acute acquired concomitant esotropia(AACE)and the healthy controls(HCs)detected by magnetic resonance imaging(MRI).METHODS:A case-control study.Eighteen subjects with AACE and eighteen HCs were enrolled.MRI scanning data were conducted in target-controlled central gaze with a 3-Tesla magnetic resonance scanner.Extraocular muscles(EOMs)were scanned in contiguous image planes 2-mm thick spanning the EOM origins to the globe equator.To form posterior partial volumes(PPVs),the LR and MR cross-sections in the image planes 8,10,12,and 14 mm posterior to the globe were summed and multiplied by the 2-mm slice thickness.The data were classified according to the right eye,left eye,dominant eye,and non-dominant eye,and the differences in mean cross-sectional area,maximum cross-sectional area,and PPVs of the MR and LR muscle in the AACE group and HCs group were compared under the above classifications respectively.RESULTS:There were no significant differences between the two groups of demographic characteristics.The mean cross-sectional area of the LR muscle was significantly greater in the AACE group than that in the HCs group in the non-dominant eyes(P=0.028).The maximum cross-sectional area of the LR muscle both in the dominant and non-dominant eye of the AACE group was significantly greater than the HCs group(P=0.009,P=0.016).For the dominant eye,the PPVs of the LR muscle were significantly greater in the AACE than that in the HCs group(P=0.013),but not in the MR muscle(P=0.698).CONCLUSION:The size and volume of muscles dominant eyes of AACE subjects change significantly to overcome binocular diplopia.The LR muscle become larger to compensate for the enhanced convergence in the AACE.
基金supported by the National Students Training Program for Innovation(Grant No.202210007029)。
文摘How the state of living muscles modulates the features of nonlinear elastic waves generated by external dynamic loads remains unclear because of the challenge of directly observing and modeling nonlinear elastic waves in skeletal muscles in vivo,considering their active deformation behavior.Here,this important issue is addressed by combining experiments performed with an ultrafast ultrasound imaging system to track nonlinear shear waves(shear shock waves)in muscles in vivo and finite element analysis relying on a physically motivated constitutive model to study the effect of muscle activation level.Skeletal muscle was loaded with a deep muscle stimulator to generate shear shock waves(SSWs).The particle velocities,second and third harmonics,and group velocities of the SSWs in living muscles under both passive and active states were measured in vivo.Our experimental results reveal,for the first time,that muscle states have a pronounced effect on wave features;a low level of activation may facilitate the occurrence of both the second and third harmonics,whereas a high level of activation may inhibit the third harmonic.Finite element analysis was further carried out to quantitatively explore the effect of active muscle deformation behavior on the generation and propagation of SSWs.The simulation results at different muscle activation levels confirmed the experimental findings.The ability to reveal the effects of muscle state on the features of SSWs may be helpful in elucidating the unique dynamic deformation mechanism of living skeletal muscles,quantitatively characterizing diverse shock wave-based therapy instruments,and guiding the design of muscle-mimicking soft materials.
基金supported by the Chinese National General Program of the National Natural Science Foundation of China,No.82072162(to XY)。
文摘Coordinated contraction of skeletal muscles relies on selective connections between the muscles and multiple classes of the spinal motoneuro ns.Howeve r,current research on the spatial location of the spinal motoneurons innervating differe nt muscles is limited.In this study,we investigated the spatial distribution and relative position of different motoneurons that control the deep muscles of the mouse hindlimbs,which were innervated by the obturator nerve,femoral nerve,inferior gluteal nerve,deep pe roneal nerve,and tibial nerve.Locations were visualized by combining a multiplex retrograde tracking technique compatible with three-dimensional imaging of solvent-cleared o rgans(3DISCO)and 3-D imaging technology based on lightsheet fluorescence microscopy(LSFM).Additionally,we propose the hypothesis that"messenger zones"exist as interlaced areas between the motoneuron pools that dominate the synergistic or antagonist muscle groups.We hypothesize that these interlaced neurons may participate in muscle coordination as messenger neurons.Analysis revealed the precise mutual positional relationships among the many motoneurons that innervate different deep muscles of the mouse.Not only do these findings update and supplement our knowledge regarding the overall spatial layout of spinal motoneurons that control mouse limb muscles,but they also provide insights into the mechanisms through which muscle activity is coordinated and the architecture of motor circuits.
基金support from the National Natural Science Foundation of China(Nos.T2222029,U21A20396,and 62127811)the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(No.XDA16020802)the CAS Project for Young Scientists in Basic Research(No.YSBR-012).
文摘In the intricate skeletal muscle tissue,the symbiotic relationship between myotubes and their supporting vasculature is pivotal in delivering essential oxygen and nutrients.This study explored the complex interplay between skeletal muscle and endothelial cells in the vascularization ofmuscle tissue.By harnessing the capabilities of three-dimensional(3D)bioprinting and modeling,we developed a novel approach involving the co-construction of endothelial and muscle cells,followed by their subsequent differentiation.Our findings highlight the importance of the interaction dynamics between these two cell types.Notably,introducing endothelial cells during the advanced phases of muscle differentiation enhanced myotube assembly.Moreover,it stimulated the development of the vascular network,paving the way for the early stages of vascularized skeletal muscle development.The methodology proposed in this study indicates the potential for constructing large-scale,physiologically aligned skeletal muscle.Additionally,it highlights the need for exploring the delicate equilibrium and mutual interactions between muscle and endothelial cells.Based on the multicell-type interaction model,we can predict promising pathways for constructing even more intricate tissues or organs.
基金supported by Korea Environment Industry&Technology Institute through Project to make multi-ministerial national biological research resources more advanced Project,funded by Korea Ministry of Environment(grant number RS-2023-00230403).
文摘Objective:To evaluate the effects of Catalpa bignonioides fruit extract on the promotion of muscle growth and muscular capacity in vitro and in vivo.Methods:Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.Cell proliferation was assessed using a 5-bromo-2’-deoxyuridine(BrdU)assay kit.Western blot analysis was performed to determine the protein expressions of related factors.The effects of Catalpa bignonioides extract were investigated in mice using the treadmill exhaustion test and whole-limb grip strength assay.Chemical composition analysis was performed using high-performance liquid chromatography(HPLC).Results:Catalpa bignonioides extract increased the proliferation of C2C12 mouse myoblasts by activating the Akt/mTOR signaling pathway.It also induced metabolic changes,increasing the number of mitochondria and glucose metabolism by phosphorylating adenosine monophosphate-activated protein kinase.In an in vivo study,the extract-treated mice showed improved motor abilities,such as muscular endurance and grip strength.Additionally,HPLC analysis showed that vanillic acid may be the main component of the Catalpa bignonioides extract that enhanced muscle strength.Conclusions:Catalpa bignonioides improves exercise performance through regulation of growth and metabolism in skeletal muscles,suggesting its potential as an effective natural agent for improving muscular strength.
基金Supported by the Science and Technology Supporting Project (Agriculture) of Jiangsu Province (BE2011452)the Special Fund Project of the National Broiler Industry Technology System (CARS-42-G23)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)~~
文摘[Objective] This study aimed to investigate the characteristics of deposition of inosine monophosphate （IMP） and intramuscular fat （IMF） in muscles of Jinghai yellow chickens and its crossbred.[Method] The characteristics of IMP and IMF deposition of 112-day-old Jinghai yellow chickens （J×J） and its two different 70-day- old crossbreeds （J×B and B×B） were analyzed. The IMP content in breast muscle and leg muscle were determined by HPLC. [Result] The contents of IMP and cor- rected inosine monophosphate （IMPc） in breast muscle were significantly or ex- tremely significantly higher than that in leg muscle of the chickens in the three groups whether in male or female chickens （P〈0.05 or P〈0.01）. There were no sig- nificant difference in the contents of IMP and IMPc between hens and roosters （P〉 0.05）. The fresh degree of breast muscle and leg muscle was 96,11%-98.16% and 87.22%-93.07%, respectively. And the fresh degree of breast muscle was higher than that of leg muscle. In the three groups, the IMF content in leg muscle was significantly higher than that in breast muscle whether in male or female chickens （P〈0.05）. The contents of IMF in breast muscle and leg muscle were 0.36%-0.75% and 1.84%-2.38%, respectively. The iMP content in breast muscle of chickens in Bx J group was extremely significantly higher than that in breast muscle of chickens in JxJ group （P〈0.01）, but the contents of IMPc and iMF of breast muscle and leg muscle of the chickens in the three groups had no significant difference （P〉0.05）. [Conclusion] To sum up, the freshness and flavor significantly differ between the breast muscle and leg muscle of chickens, but show no significant difference among the three groups.
文摘Objective:To provide new insights for the evaluation and diagnosis of chronic neck pain(CNP).Methods:22 patients with CNP and 22 healthy individuals were recruited from South China Normal University,who were all college students.The subjects'neck extensor muscle strength in the head neutral position,the natural anteversion position,and the maximum forward flexion position were measured by an isometric muscle strength tester respectively.The neck extensor strength of CNP patients and healthy subjects were compared.Results:In the neutral position,the maximum isometric muscle strength of neck extensor muscles was 12.31 kg for CNP patients and 15.16 kg for healthy individuals,resulting in a ratio of 81%strength in patients compared to healthy subjects.This difference was highly significant(P<0.000).In the natural anteversion position,the respective values were 12.6 kg for CNP patients and 15.05 kg for healthy individuals,with a ratio of 83%,and a significant difference between groups(P<0.001).In the maximum forward flexion position of the head,the values were 13.36 kg for CNP patients and 16.15 kg for healthy individuals,with a ratio of 82%,and a highly significant difference(P<0.000).Conclusion:The neck extensor muscle strength levels in college students with CNP were significantly lower compared to healthy college students across all measured positions.
基金Supported by the National Sci-tech Support Plan(2012BAD39B04)the Special Fund for Yangzhou Municipal Key Agricultural Science and Technology Projects(YZ2011067)Special Fund for the Industrial Technology System Construction of Modern Agriculture(nycytx-42-G1)~~
文摘[Objective] This study aimed to explore the effects of IGFs system on the growth of goose skeletal muscles. [Method] Quantitative fluorescence PCR technique was adopted to study the variety- and gender-specificity in the expression of GHR, IGF-I, IGF-IR and IGFBP-3 genes in leg muscles of 70-day-old Taihu goose and Wanxi white goose, and the correlation between their expression and carcass traits was also investigated. [Resull] There was no variety difference in the expression of GHR, IGF-t, IGF-IR and IGFBP-3 genes in leg muscles of Taihu goose and Wanxi white goose, but there were significant variety differences in the body weight and leg muscle weight. There were no gender difference in the body weight, leg muscle weight and the rate of leg muscles; except IGF-I mRNA level that was significantly higher in male Taihu goose than in female ones（P=0.032）, there was no gender dif- ference in the expression of other three genes. Among the four tested genes, only IGFBP-3 mRNA exhibited an extremely significantly positively correlation with the rate of leg muscles, suggesting that IGFs may play a role in regulating the growth of leg muscles via IGFBP-3 system in 70-day-old goose. [Conclusion] This study provides theoretical basis for research in the skeletal growth and development.
文摘Summary: The operation methods, clinical classification, postoperative function exercise of gluteal muscles contracture were investigated. Clinically and retrospectively, treatment of 1280 patients with gluteal muscles contracture, being subjected to a 'Z-shaped' release lengthening operation and efficiency exercise, was clearly standardized. All the cases were followed up from 3 months to 2 years with the effective rate being 100 %, the cure rate being 98. 5 %, the recent complications being 5%, and the far complications being 0. 2 %. It was concluded that the clear diagnosis combined with standarized operation and efficiency functional exercise could greatly improve the therapeutic effects of gluteal muscles contracture.
基金This work was supported by National Key R&D Program of China(2018YFB2000903)NationalNatural Science Foundation of China under Grant Numbers 51875507 and 51890885,Open Fund of Key Laboratory of Electronic Equipment Structure Design in Xidian University(EESD1905)applied by Author Yangqiao Lin,which support the research,the Fundamental Research Funds for the Central Universities,and Director’s Fund of State Key Laboratory of Fluid Power and Mechatronic Systems.
文摘Developing artificial muscles that can replace biological muscles to accomplish various tasks iswhat we have long been aiming for.Recent advances in flexible materials and 3D printing technology greatly promote the development of artificial muscle technology.A variety of flexible material-based artificial muscles that are driven by different external stimuli,including pressure,voltage,light,magnetism,temperature,etc.,have been developed.Among these,fluid-driven artificial muscles(FAMs),which can convert the power of fluid(gas or liquid)into the force output and displacement of flexible materials,are the most widely used actuation methods for industrial robots,medical instruments,and human-assisted devices due to their simplicity,excellent safety,large actuation force,high energy efficiency,and low cost.Herein,the bio-design,manufacturing,sensing,control,and applications of FAMs are introduced,including conventional pneumatic/hydraulic artificial muscles and several innovative artificial muscles driven by functional fluids.What’s more,the challenges and future directions of FAMs are discussed.
基金Supported by the Research Project of Future Growth Engine Flagship Project,No:CN16040)by Minister of Science,ICT and Future Planningthe National Research Foundation of Korea grant funded by the Korea government(Ministry of Science,ICT and Future Planning),No.NRF-2017R1A2B4011478
文摘BACKGROUND De-afferentation or non-weight bearing induces rapid cortical and spinalα-motor neuron excitability.Author supposed that an end-effector type gait robot(EEGR)could provide patients with a training condition that was specific enough to activate rapid cortical/spinal neuroplasticity,leading to immediate muscle strengthening.The electromyographic and biomechanical comparisons were conducted.AIM To compare the electromyographic activities of the thigh and shank muscles and isometric peak torque(PT)before and after walking training on a floor or in the end-effector gait robot.METHODS Twelve outpatients without ambulatory dysfunction were recruited.Order of two interventions(5-min training on a floor at a comfortable pace or training in an EEGR with non-weight bearing on their feet and 100%guidance force at 2.1 km/h)were randomly chosen.Isometric PT,maximal ratio of torque development,amplitude of compound motor action potential(CMAP),and area under the curve(AUC)were evaluated before and 10 min after both interventions.RESULTS The degree of PT improvement of the dominant knee flexors was larger in the EEGR than on the floor(9.6±22.4 Nm/BW,P<0.01).The EEGR-trained patients had greater PT improvement of the dominant knee extensors than those who trained on the floor(4.5±28.1 Nm/BW,P<0.01).However,all electromyographic activities of the thigh and shank muscles(peak CMAP,mean and peak AUC)were significantly lower for the use of the EEGR than walking on the floor.CONCLUSION Immediate strengthening of the knee flexors and extensors was induced after the 5-min EEGR training,despite reduced muscular use.
文摘According to the deficiency of the present model of pneumatic artificialmuscles (PAM), a serial model is built up based on the PAM's essential working principle with theelastic theory, it is validated by the quasi-static and dynamic experiment results, which are gainedfrom two experiment systems. The experiment results and the simulation results illustrate that theserial model has made a great success compared with Chou's model, which can describe the forcecharacteristics of PAM more precisely. A compensation item considering the braid's elasticity andthe coulomb damp is attached to the serial model based on the analysis of the experiment results.The dynamic experiment proves that the viscous damp of the PAM could be ignored in order to simplifythe model of PAM. Finally, an improved serial model of PAM is obtained.
基金financial support obtained from the National Key Research and Development Program of China (2020YFB1312900)the National Natural Science Foundation of China (21975281)+1 种基金Key Research Project of Zhejiang lab (No. K2022NB0AC04)Jiangxi Double Thousand Talent Program (No. jxsq2020101008)。
文摘Artificial yarn muscles show great potential in applications requiring low-energy consumption while maintaining high performance. However, conventional designs have been limited by weak ion-yarn muscle interactions and inefficient “rocking-chair” ion migration. To address these limitations, we present an electrochemical artificial yarn muscle design driven by a dual-ion co-regulation system. By utilizing two reaction channels, this system shortens ion migration pathways, leading to faster and more efficient actuation. During the charging/discharging process, PF_6~- ions react with carbon nanotube yarn, while Li~+ ions react with an Al foil. The intercalation reaction between PF_6~- and collapsed carbon nanotubes allows the yarn muscle to achieve an energy-free high-tension catch state. The dual-ion coordinated yarn muscles exhibit superior contractile stroke, maximum contractile rate, and maximum power densities, exceeding those of “rocking-chair” type ion migration yarn muscles. The dual-ion co-regulation system enhances the ion migration rate during actuation, resulting in improved performance. Moreover, the yarn muscles can withstand high levels of isometric stress, displaying a stress of 61 times that of skeletal muscles and 8 times that of “rocking-chair” type yarn muscles at higher frequencies. This technology holds significant potential for various applications, including prosthetics and robotics.
基金This project is supported by National Natural Science Foundation of China(No.50375034).
文摘An exoskeleton force feedback dataglove is developed, which uses the pneumatic artificial muscles as actuators. On the basis of the simplified hand model, the motion equation is deduced according to the theory of Denavit-Hartenberg. The model of the equivalent contact forces exerted by the object on the finger is proposed. By the principle of virtual work, the static equilibrium of finger is established. The force Jacobian matrix of finger is calculated, and then the joint torques of the finger when grasping objects are obtained. The theory and structure of the force feedback datagolve are introduced. Based on the theory of motion stabilization of four-bar linkage, the flexion angles of joints are measured. The torques on finger joints caused by the output forces of pneumatic artificial muscles are calculated. The output forces of pneumatic artificial muscle, whose values are controlled by its inner pressure, can be calculated by the joint torques of the finger when grasping objects. The arms of force, driving torques and the needed output forces of pneumatic muscle are calculated for each joint of the index finger. The criterion of output force of pneumatic muscle is given.
文摘The purpose of this study was to show the benefit of visualizing a tree-dimensional (3D) image of the tongue’s muscle structure, which until now has been regarded as fully understood. Until now, no suitable 3D observation methods have been developed for soft tissue, such as the tongue, using?histological magnification. For this purpose, this study used a micro-computed tomographic method (micro-CT) and image processing after the fixation, decalcification, and dehydration of a mouse tongue. Results: 3D rendered images of tongue muscles obtained by micro-CT showed every muscle and their relationships to each other. The superior longitudinal and the hyoglossus muscles of the tongue made up one group, while the inferior longitudinal and the styloglossus muscles of the tongue made up another. The boundary of the two muscles in each group was difficult to distinguish. On the other hand, what appear to be newly described muscles were identified. These results indicate that our micro-CT method is beneficial and that classical knowledge of tongue muscles derived from two-dimensional (2D) images does not fully describe the actual complexity of the tongue muscles. In our opinion, 3D rendered images mixed with raw structure can provide a more in-depth picture of the tongue from an integrated as well as an analytical perspective.
文摘This study aimed to clarify the immediate effect that trunk muscle exercise has on muscle reaction time, and to clarify the effect of 2-week exercise on muscle reaction time. The study showed that as for immediate effects, the muscle reaction time was significantly shortened in the TrA/OI (transversus abdominis muscle/obliquus internus muscle) of two exercise groups. However, the immediate effect seen before the 2-week trunk muscle exercise intervention disappeared after the intervention. In addition, trunk muscle exercise intervention for 2 weeks significantly shortened the muscle reaction time of TrA/OI in one exercise group. Furthermore, shortening of the muscle reaction time was also observed in the MF (multifidus muscle) of both exercise groups. The factors affecting the muscle reaction time of TrA observed in this study were considered to be an improvement of neuromuscular function by the central nervous system. It was also considered that 2-week exercise intervention has a lower value after 2 weeks due to an improvement of neuromuscular function by the central nervous system, and an immediate effect could not be obtained with the same exercise as at the time of intervention.
文摘Myasthenia gravis (MG) is an autoimmune disorder involving the neuromuscular junction that frequently affects the extra-ocular muscles (EOMs). It has been described as a very rare cause of bilateral EOM atrophy, but histological analysis of such cases is lacking. A 66-year-old man presented with two months of right eyelid drooping and vertical diplopia. Examination showed bilateral ophthalmoparesis and complete right ptosis. The remainder of his exam was normal, and an MRI showed small EOMs. Acetylcholine receptor antibodies were elevated, establishing the diagnosis of MG. Oral corticosteroids and pyridostigmine followed by azathioprine improved his ptosis, but not his ophthalmoparesis. One year later he had surgical correction of his diplopia, and the resected superior rectus muscle showed complete replacement of EOM by connective tissue. MG can rarely cause bilateral EOM atrophy, which is characterized histologically by fibrosis in the muscle itself. Atrophy in the EOMs of a myasthenic patient may indicate a poor response to medical management alone.
文摘The effects of 2-[p-(Dimethylamino)styryl] pyridine methiodide(DSPM)on slow response action potential(SRAP)and slow inward current(Isi) of guinea pig papillary muscles were studied by intracellular microelectrodes and voltage clamp techniques.The APA and V_(max) of SRAP induced by high K￣+were decreased after 50 min of perfusion with DSPM solu- tion. Isi was suppressed from a peak value of8.8± 1.6μA to 5.7± 1.8μA, The results indicated that DSPM has a selective blocking effect on calcium channel.
