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BACKGROUND: Human gait involves activities in nervous and musculoskeletal dynamics to modulate joint torques with time continuously for adapting to varieties of walking conditions. OBJECTIVE: The goal of this paper is to estimate the joint torques of lower limbs in human gait based on Gaussian process. METHOD: The potential uses of this study include optimization of exoskeleton assistance, control of the active prostheses, and modulating the joint torque for human-like robots. To achieve this, Gaussian process (GP) based data fusion algorithm is established with joint angles as the inputs. RESULTS: The statistic nature of the proposed model can explore the correlations between joint angles and joint torques, and enable accurate joint-torque estimations. Experiments were conducted for 5 subjects at three walking speed (0.8 m/s, 1.2 m/s, 1.6 m/s). CONCLUSION: The results show that it is possible to estimate the joint torques at different scenarios.

The purpose of this cross-sectional study was to determine the precision and accuracy of the measurement of finger motion with a depth camera. Fifty-five healthy adult hands were included. Measurements were done with a depth camera and compared with traditional manual goniometer measurements. Repeated measuring showed that the overall repeatability and reproducibility of extension measured with the depth camera were within 3° and 4° and that of flexion were within 13° and 14°. Compared with traditional manual goniometry, biases of extension of all finger joints and flexion of metacarpophalangeal joints were less than 5°, and the average bias of flexion of proximal and distal interphalangeal joints was 29°. We conclude that the measurement of finger extension and flexion of the metacarpophalangeal joints with a depth camera was reliable, but improvement is required in the precision and accuracy of interphalangeal joint flexion.

Horner syndrome is a clinical constellation that presents with miosis, ptosis, and facial anhidrosis. It is important as a warning sign of the damaged oculosympathetic chain, potentially with serious causes. However, the diagnosis of Horner syndrome is operator dependent and subjective. This study aims to present an objective method that can recognize Horner sign from facial photos and verify its accuracy. A total of 173 images were collected, annotated, and divided into training and testing groups. Two types of classifiers were trained (two-stage classifier and one-stage classifier). The two-stage method utilized the MediaPipe face mesh to estimate the coordinates of landmarks and generate facial geometric features accordingly. Then, ten machine learning classifiers were trained based on this. The one-stage classifier was trained based on one of the latest algorithms, YOLO v5. The performance of the classifier was evaluated by the diagnosis accuracy, sensitivity, and specificity. For the two-stage model, the MediaPipe successfully detected 92.2% of images in the testing group, and the Decision Tree Classifier presented the highest accuracy (0.790). The sensitivity and specificity of this classifier were 0.432 and 0.970, respectively. As for the one-stage classifier, the accuracy, sensitivity, and specificity were 0.65, 0.51, and 0.84, respectively. The results of this study proved the possibility of automatic detection of Horner syndrome from images. This tool could work as a second advisor for neurologists by reducing subjectivity and increasing accuracy in diagnosing Horner syndrome.

This paper proposes a super-twisting terminal sliding mode-based robust impedance controller to improve the compliance and robustness in robot-environment interaction. Based on the desired impedance dynamics, an impedance reference trajectory is constructed. Then, based on a super-twisting terminal sliding-mode, the robust impedance controller is designed to guarantee the achievement of the desired impedance dynamics in finite-time through the finite-time convergence of an impedance error. The main contribution of this paper is that the proposed control improves impedance control robustness by using the super-twisting nonsingular terminal sliding-mode without causing the chattering problem. The finite-time stability of the closed-loop control system is validated by theoretical analysis based on the Lyapunov theory, and the control effectiveness is illustrated by simulations on a two-link robot manipulator.

The exoskeleton has emerged as a promising technology to enhance humans’ strength and boost users’ efficiency. In order to provide congruent human–machine interaction for assisting the users, exoskeletons should have knowledge of human’s planned action and accordingly command the robot by the designed controller. It means the ubiquitous aspect of exoskeletons lies on motion intent understanding and active compliance control. In the last decade, extensive research has been conducted on the two topics. However, no major breakthrough has been made. Thus, a systematic review and analysis on this very subject is of great significance in developing exoskeletons. Within this context, this review first surveys the history of lower limb exoskeletons to summarize the various technologies for realizing transparent human exoskeleton coordination. Then, an overview about motion intent understanding and compliance control strategies are presented in detail. Furthermore, the future trend and research directions are also outlined.

The poultry industry has become a global leader in livestock farming over the past few decades. Poultry production has a large consumer market as an integrated industry producing high-protein foods.

Purpose Treatment of total brachial plexus avulsion (TBPA) is a challenge in the clinic, especially the restoration of hand function. The current main surgical order is from proximal to distal joints. The purpose of this study was to demonstrate the outcomes of “distal to proximal” surgical method. Methods Thirty-nine patients underwent contralateral C7 (CC7) nerve transfer to directly repair the lower trunk (CC7-LT) and phrenic nerve transfer to the suprascapular nerve (PN-SSN) during the first stage, followed by free functional gracilis transplantation (FFGT) for elbow flexion and finger extension. Muscle strength of upper limb, degree of shoulder abduction and elbow flexion, and Semmes–Weinstein monofilament test and static two-point discrimination of the hand were examined according to the modified British Medical Research Council (mBMRC) scoring system. Results The results showed that motor recovery reached a level of M3 + or greater in 66.7% of patients for shoulder abduction, 87.2% of patients for elbow flexion, 48.7% of patients for finger extension, and 25.6% of patients for finger flexion. The mean shoulder abduction angle was 45.5° (range 0–90°), and the average elbow flexion angle was 107.2° (range 0–142°), with 2.5 kg average flexion strength (range 0.5–5 kg). In addition, protective sensibility (≥ S2) was found to be achieved in 71.8% of patients. Conclusion In reconstruction of TBPA, CC7 transfer combined with free functional gracilis transplantation is an available treatment method. It could help patients regain shoulder joint stability and the function of elbow flexion and finger extension and, more importantly, provide finger sensation and partial finger flexion function. However, the pick-up function was unsatisfied, which needed additional surgery.

The accurate measurement of human joint torque is one of the research hotspots in the field of biomechanics. However, due to the complexity of human structure and muscle coordination in the process of movement, it is difficult to measure the torque of human joints in vivo directly. Based on the traditional elbow double-muscle musculoskeletal model, an improved elbow neuromusculoskeletal model is proposed to predict elbow muscle torque in this paper. The number of muscles in the improved model is more complete, and the geometric model is more in line with the physiological structure of the elbow. The simulation results show that the prediction results of the model are more accurate than those of the traditional double-muscle model. Compared with the elbow muscle torque simulated by OpenSim software, the Pearson correlation coefficient of the two shows a very strong correlation. One-way analysis of variance (ANOVA) showed no significant difference, indicating that the improved elbow neuromusculoskeletal model established in this paper can well predict elbow muscle torque.

Background Intestinal health plays a pivotal role in broiler chicken growth. Oregano aqueous extract (OAE) effectively exerts anti-inflammatory and antibacterial effects. However, the protective effects of OAE on intestinal health in broilers and the underlying mechanism remain unclear. This study aimed to investigate the potential effects of OAE on growth performance, the gut microbiota and intestinal health. A total of 840 1-day-old male and female broilers (Arbor Acres) were randomly allocated into 6 groups as follows: basal diet (Con), Con + antibiotics (Anti, Mycolistin sulfate 7 g/kg, Locke sand arsine 35 g/kg), Con + 400, 500, 600 and 700 mg/kg OAE (OAE400, OAE500, OAE600 and OAE700). Subsequently, fermentation in vitro together with oral administration trials were carried out to further assess the function of OAE on intestinal health of broilers. Results Dietary 700 mg/kg OAE supplementation resulted in an increase (P P P IL-4 and IL-10 at D42. In addition, dietary OAE addition increased the abundance of Firmicutes (P = 0.087) and Lactobacillus (P P in vitro fermentation test, OAE significantly increased (P Lactobacillus, decreased (P Unspecified_Enterobacteriaceae, and increased the content of acetic acid (P P P = 0.073) when giving OAE fermentation supernatant. Conclusions Dietary OAE addition could maintain intestinal health and improve growth performance through enhancing intestinal mucosal immunity and barrier function mediated by gut microbiota changes.

This paper presents an impedance learning-based adaptive control strategy for series elastic actuator (SEA)-driven compliant robots without the measurement of the robot–environment interaction force. The adaptive controller is designed based on the command filter-based adaptive backstepping approach, where a command filter is used to decrease computational complexity and avoid the requirement of high derivatives of the robot position. In the controller, environmental impedance profiles and robotic parameter uncertainties are estimated using adaptive learning laws. Through a Lyapunov-based theoretical analysis, the tracking error and estimation errors are proven to be semiglobally uniformly ultimately bounded. The control effectiveness is illustrated through simulations on a compliant robot arm.

BackgroundRadial, ulnar, or median nerve injuries are common peripheral nerve injuries. They usually present specific abnormal signs on the hands as evidence for hand surgeons to diagnose. However, without specialized knowledge, it is difficult for primary healthcare providers to recognize the clinical meaning and the potential nerve injuries through the abnormalities, often leading to misdiagnosis. Developing technologies for automatically detecting abnormal hand gestures would assist general medical service practitioners with an early diagnosis and treatment.MethodsBased on expert experience, we selected three hand gestures with predetermined features and rules as three independent binary classification tasks for abnormal gesture detection. Images from patients with unilateral radial, ulnar, or median nerve injuries and healthy volunteers were obtained using a smartphone. The landmark coordinates were extracted using Google MediaPipe Hands to calculate the features. The receiver operating characteristic curve was employed for feature selection. We compared the performance of rule-based models with logistic regression, support vector machine and of random forest machine learning models by evaluating the accuracy, sensitivity, and specificity.ResultsThe study included 1,344 images, twenty-two patients, and thirty-four volunteers. In rule-based models, eight features were finally selected. The accuracy, sensitivity, and specificity were (1) 98.2, 91.7, and 99.0% for radial nerve injury detection; (2) 97.3, 83.3, and 99.0% for ulnar nerve injury detection; and (3) 96.4, 87.5, and 97.1% for median nerve injury detection, respectively. All machine learning models had accuracy above 95% and sensitivity ranging from 37.5 to 100%.ConclusionOur study provides a helpful tool for detecting abnormal gestures in radial, ulnar, or median nerve injuries with satisfying accuracy, sensitivity, and specificity. It confirms that hand pose estimation could automatically analyze and detect the abnormalities from images of these patients. It has the potential to be a simple and convenient screening method for primary healthcare and telemedicine application.

This paper investigated the effect of the modification of 5A zeolite by KCl solution for eliminating Cu2+ from aqueous solutions. The results show that the adsorbent modified with 0.5 M KCl exhibited the best performance, and the removal rate is 82.12%, the adsorption capacity is 53.1 mg/g, when the initial concentration of Cu(II) is 63.4 mg/L, In addition, the extension of the adsorption time will also increase the adsorption capacity. This indicates that KCl can effectively increase the adsorption capacity of Cu2+. It is hoped that this method can be applied to wastewater treatment.

Background: Intestinal health plays an important role in broiler chicken production. Oregano aqueous extract (OAE) effectively exerts anti-inflammatory and antibacterial effects. However, the protective effects of OAE on gut health in broilers and the underlying mechanism remain unclear. This study aimed to investigate the potential effects of OAE on production performance, the intestinal microbiome and gut health, and to verify the effect of intestinal microbe on gut health. Results: Dietary 700 mg/kg OAE supplementation resulted in an increase (P < 0.05) in body weight and a decrease (P < 0.05) in feed conversion ratio than the control at D42 of the trial. Compared to the control, OAE addition resulted in lower (P < 0.05) jejunal crypt depth and the relative mRNA expression of IL-4 and IL-10 at D42. Dietary OAE increased (P < 0.05) the abundance of Firmicutes and Lactobacillus in the cecum, and affected the content of short-chain fatty acids. In addition, the results of microorganisms affected by OAE in vitro were consistent with those in vivo. The relative mRNA expression of IL-4 was significantly increased (P < 0.05) by feeding oregano fermentation microorganisms at D42. And the secretion of SIgA was significantly increased (P < 0.05) in the ileum in S group.Conclusions: Dietary OAE addition could increase the abundance of intestinal Lactobacillus and acetic acid content, which were capable to improve intestinal mucosal immunity and barrier function, thus maintaining intestinal health and improving production performance.

Estimating the joint torques of lower limbs in human gait, known as motion intent understanding, is of great significance in the control of lower limb exoskeletons. This study presents novel soft smart shoes designed for motion intent learning at unspecified walking speeds using long short-term memory with a convolutional autoencoder. The smart shoes serve as a wearable sensing system consisting of a soft instrumented sole and two 3D motion sensors that are nonintrusive to the human gait and comfortable for the wearers. A novel data structure is developed as a “sensor image” for the measured ground reaction force and foot motion. A convolutional autoencoder is established to fuse multisensor datasets and extract the hidden features of the sensor images, which represent the spatial and temporal correlations among the data. Then, long short-term memory is exploited to learn the multiscale, highly nonlinear input-output relationships between the acquired features and joint torques. Experiments were conducted on five subjects at three walking speeds (0.8 m/s, 1.2 m/s, and 1.6 m/s). Results showed that 98% of the ${r}^{2}$ values were acceptable in individual testing and 75% of the ${r}^{2}$ values were acceptable in interindividual testing. The proposed method is able to learn the join torques in human gait and has satisfactory generalization properties.

The C5-C6 nerve roots are usually spared from avulsion after brachial plexus injury (BPI) and can thus be used as donors for nerve repair. A BPI rat model with C5-C6 nerve root stumps has been established in our previous work. The aim of this study was to test whether riluzole loaded into a thermosensitive hydrogel could applied locally in the nerve root stumps of this BPI rat model, thus increasing the reparative effect of the nerve root stumps. Nile red (a hydrophobic dye) was used as a substitute for riluzole since riluzole itself does not emit light. Nile red, loaded into a thermosensitive hydrogel, was added to the nerve root stumps of the BPI rat model. Additionally, eighteen rats, with operation on right brachial plexus, were evenly divided into three groups: control (Con), thermosensitive hydrogel (Gel) and thermosensitive hydrogel loaded with riluzole (Gel + Ri) groups. Direct nerve repair was performed after local riluzole release for two weeks. Functional and electrophysiological evaluations and histological assessments were used to evaluate the reparative effect 8 weeks after nerve repair. Nile red was slowly released from the thermosensitive hydrogel and retrograde transport through the nerve root stumps to the motoneurons, according to immunofluorescence. Discernible functional recovery began earlier in the Gel + Ri group. The compound muscle action potential, ChAT-expressing motoneurons, positivity for neurofilaments and S100, diameter of regenerating axons, myelin sheath thickness and density of myelinated fibers were markedly increased in the Gel + Ri group compared with the Con and Gel groups. Our results indicate that the local administration of riluzole could undergo retrograde transportation through C5-C6 nerve root stumps, thereby promoting neuroprotection and increasing nerve regeneration.

Although human–exoskeleton systems have tremendous potentials for rehabilitation training, transparent human–exoskeleton interaction has not been achieved for late-phase rehabilitation. To cope with this challenge, an adaptive pilot intent prediction–based control algorithm is proposed to achieve compliant motion coordination. A novel surface electromyography signal processing method providing definite physical meaning and high computational efficiency is derived. The state space model of human musculoskeletal system is developed with the input of the processed surface electromyography. Adaptive parameter estimation is employed to cope with the emerging dynamics. It integrates the advantages of surface electromyography signals which imply muscle contraction in advance and force signals with high stability. Based on the coupled human–exoskeleton system dynamics, transparent control of a human–exoskeleton system is realized. Experimental results show that the computational efficiency of the proposed surface electromyography processing method is 129% higher than the energy kernel method, and the maximum interactive force is reduced about 15 N compared with impedance control.

MicroRNA-217-5p (miR-217-5p) has been implicated in cell proliferation; however, its role in skeletal muscle stem cells (SkMSCs) remains unknown. The present study aimed to explore the roles of miR‑217‑5p in the biological characteristics of SkMSCs. SkMSCs were identified by cell surface markers using flow cytometry. The present study observed that miR‑217‑5p mimics accelerated the proliferation and suppressed the differentiation in SkMSCs. In addition, the results of the present study revealed that fibroblast growth factor receptor 2 (FGFR2) was a target of miR‑217‑5p, as miR‑217‑5p bound directly to the 3'‑untranslated region of FGFR2 mRNA, resulting in increased FGFR2 mRNA and protein levels. In addition, the present study suppressed the expression of FGFR2 in SkMSCs using a selective FGFR inhibitor AZD4547 and detected the efficiency of inhibition by reverse transcription‑quantitative PCR and western blotting. miR‑217‑5p levels were positively associated with FGFR2 expression, which was upregulated and accelerated the proliferation of SkMSCs compared with that of the miR‑NC group. Collectively, these results demonstrated that miR‑217‑5p may act as a myogenesis promoter in SkMSCs by directly targeting FGFR2 and may regulate the myogenesis of these cells.

To validate the use of key point matrix technology based contactless automatic measurement for evaluation of joint motion of hand.Thirty-three volunteers were enrolled to evaluate the extension and flexion of hand joints between May 2021 and November 2021. There were 20 males and 13 females, the age ranged from 16 to 70 years with an average of 30.2 years. The extension angles of 14 joints of 5 fingers (including hyperextension) and the flexion angles of 12 joints of 4 fingers (excluding thumb) of volunteers were measured by key point matrix technology and manual goniometer, respectively. Then 5 participants and repeated measurement experiment were employed to test the system repeatability and accuracy; 28 participants and paired measurement experiment were employed to test the system accuracy.The average repeatability of finger joint motion measured by the key point matrix technology was 1.801° (extension) and 7.823° (flexion), respectively. Compared with manual measurement, the average differences of each finger joint measured by the key point matrix technology were 3.225° in extension and 14.145° in flexion, respectively. The key point matrix technology based contactless automatic evaluation system offered excellent consistency with the manual goniometers (The key point matrix technology based contactless automatic evaluation provides sufficient measurement repeatability and accuracy in evaluation for the joint motion of hand.探讨关键点矩阵技术用于手指关节运动角度无接触式智能测量中的可行性。.将2021年5月—11月符合选择标准的33名志愿者纳入研究。其中男20名，女13名；年龄16～70岁，平均30.2岁。利用关键点矩阵技术和手工角度尺分别测量志愿者五指14个关节伸直（含过伸）角度和四指（不含拇指）12个关节屈曲角度。随机选择5名志愿者行小样本组间重复测量对比观察，评价测量方法的重复性及准确性；随机选择28名志愿者行大样本配对准确性比较观察，评价测量方法的准确性。.关键点矩阵技术测量手指关节运动角度的平均重复性分别为1.801°（伸直）和7.823°（屈曲）。与手工测量相比，手指各关节伸直角度平均差值为3.225°，屈曲角度平均差值为14.145°。两种方法测量结果整体一致性较强（基于关键点矩阵技术的手指关节运动角度测量重复性和准确性好，各关节伸直角度和各掌指关节屈曲角度的准确性符合临床要求。.

This study aimed to investigate outcomes after extremity arterial injury repair and examined the association between outcomes and the degree of soft tissue injury and vascular repair methods.A retrospective study was conducted on 106 patients (108 cases) who underwent emergent microsurgical repair of extremity arterial injury due to trauma and non-perfusion of the affected extremity. The cases were divided into three groups by degree of associated soft tissue injuries: (A) adequate soft tissue coverage over the injured major vessels after radical debridement, (B) inadequate soft tissue coverage over the injured major vessels after radical debridement, and (C) radical debridement was not feasible due to unclear extent of injured soft tissue. Differences in vascular repair methods and outcomes among the three groups were analyzed.In Group A (n = 61), microvascular suture and vessel graft achieved 95.1% and 85.0% successful limb reperfusion, respectively. In Group B (n = 31), vessel reconstruction with flap coverage achieved 100% successful reperfusion. Vessel graft achieved 28.6% successful limb reperfusion, while there were no cases of successful reperfusion using microvascular sutures. In Group C (n = 16), no vascular repair method achieved successful reperfusion. There were significant differences among the three groups in successful reperfusion (The extent of associated soft tissue injury was associated with different vascular repair methods and outcomes. We propose a new system for classifying these injuries according to the degree of associated soft tissue injury.

Intensive selective breeding for high growth rate and body weight cause excess abdominal fat in broilers. Gut microbiota and folic acid were reported to regulate lipid metabolism. A total of 210 one-day-old broilers were divided into the control (folic acid at 1.3 mg/kg) and folic acid groups (folic acid at 13 mg/kg) to illustrate the effects of folic acid on growth performance, abdominal fat deposition, and gut microbiota, and the experiment lasted 28 d. Results revealed that dietary folic acid addition decreased abdominal fat percentage (

Background: Range of motion (ROM) measurements are essential for diagnosing and evaluating upper extremity conditions. Clinical goniometry is the most commonly used methods but it is time-consuming and skill-demanding. Recent advances in human tracking algorithm suggest potential for automatic angle measuring from RGB images. It provides an attractive alternative for at-distance measuring. However, the reliability of this method has not been fully established. The purpose of this study is to evaluate if the results of algorithm are as reliable as human raters in upper limb movements.Methods: Thirty healthy young adults (20 males, 10 females) participated in this study. Participants were asked to performed a 6-motion task including movement of shoulder, elbow and wrist. Images of movements were capture by commercial digital camera. Each movement was measured by a pose tracking algorithm and compared with the surgeon-measurement results. The mean differences between the two measurements were compared. Pearson correlation coefficients were used to determine the relationship. Reliability was investigated by the intra-class correlation coefficients.Results: Comparing this algorithm-based method with manual measurement, the mean differences were less than 3 degrees in 5 motions (shoulder abduction: 0.51; shoulder elevation: 2.87; elbow flexion:0.38; elbow extension:0.65; wrist extension: 0.78) except wrist flexion. All the intra-class correlation coefficients were larger than 0.60. The Pearson coefficients also showed high correlations between the two measurements (pConclusions: Our results indicated that pose estimation is a reliable method to measure the shoulder and elbow angles, supporting RGB images for measuring joint ROM. Our results proved the possibility that patients can assess their ROM by photos taken by a digital camera.Trial registration: This study was registered in the Clinical Trials Center of The First Affiliated Hospital, Sun Yat-sen University (2021-387).

Objective. This study aimed to evaluate whether the site of C7 neurotomy affects spinal cord glial cell activation and pain-related behavior on the paralyzed side in a rat stroke model. Methods. After middle cerebral artery occlusion (MCAO) was induced in male Sprague-Dawley rats, they underwent C7 neurotomy 0, 2, and 4 mm distal to the intervertebral foramen on the paralyzed side. Pain-related behavior and immunofluorescence examination of spinal cord glial cell activation in the ipsilateral C7 dorsal horn were evaluated. Results. Mechanical paw withdrawal threshold (MPWT) was lower, and the number of microglia and astrocytes (/mm2) was higher as the distance between the site of C7 neurotomy and the intervertebral foramen decreased from 4 mm to 0. Conclusion. The site of C7 neurotomy affects MPWT and spinal cord glial proliferation in rats with MCAO. Nerve division closer to intervertebral foramen resulted in lower MPWT and higher degree of glial proliferation in the spinal cord.

Background Telemedicine support virtual consultations and evaluations in hand surgery for patients in remote areas during the COVID-19 era. However, traditional physical examination is challenging in telemedicine and it is inconvenient to manually measure the hand range of motion (ROM) from images or videos. Here, we propose an automatic method using the hand pose estimation technique, aiming to measure the hand ROM from smartphone images. Methods Twenty-eight healthy volunteers participated in the study. An eight-hand gestures measurement protocol and the Google MediaPipe Hands were used to analyze images and calculate the ROM automatically. Manual goniometry was also performed according to the guideline of the American Medical Association. The correlation between the automatic and manual methods was analyzed by the intraclass correlation coefficient and Pearson correlation coefficient. The clinical acceptance was testified using Bland-Altman plots. Results A total of 32 parameters of each hand were measured by both methods, and 1792 measurement results were compared. The mean difference between automatic and manual methods is −2.21 ± 9.29° in the angle measurement and 0.48 ± 0.48 cm in the distance measurement. The intraclass correlation coefficient of 75% of parameters was higher than 0.75, the Pearson correlation coefficient of 84% of parameters was over 0.6, and 40.6% of parameters reached well-accepted clinical agreements. Conclusions The proposed method provides a helpful protocol for automatic hand ROM measurement based on smartphone images and the MediaPipe Hands pose estimation technique. The automatic measurement is acceptable and comparable with existing methods, showing a possible application in the telemedicine examination of hand surgery.

Background Range of motion (ROM) measurements are essential for diagnosing and evaluating upper extremity conditions. Clinical goniometry is the most commonly used methods but it is time-consuming and skill-demanding. Recent advances in human tracking algorithm suggest potential for automatic angle measuring from RGB images. It provides an attractive alternative for at-distance measuring. However, the reliability of this method has not been fully established. The purpose of this study is to evaluate if the results of algorithm are as reliable as human raters in upper limb movements. Methods Thirty healthy young adults (20 males, 10 females) participated in this study. Participants were asked to performed a 6-motion task including movement of shoulder, elbow and wrist. Images of movements were captured by commercial digital cameras. Each movement was measured by a pose tracking algorithm (OpenPose) and compared with the surgeon-measurement results. The mean differences between the two measurements were compared. Pearson correlation coefficients were used to determine the relationship. Reliability was investigated by the intra-class correlation coefficients. Results Comparing this algorithm-based method with manual measurement, the mean differences were less than 3 degrees in 5 motions (shoulder abduction: 0.51; shoulder elevation: 2.87; elbow flexion:0.38; elbow extension:0.65; wrist extension: 0.78) except wrist flexion. All the intra-class correlation coefficients were larger than 0.60. The Pearson coefficients also showed high correlations between the two measurements (p Conclusions Our results indicated that pose estimation is a reliable method to measure the shoulder and elbow angles, supporting RGB images for measuring joint ROM. Our results presented the possibility that patients can assess their ROM by photos taken by a digital camera. Trial registration This study was registered in the Clinical Trials Center of The First Affiliated Hospital, Sun Yat-sen University (2021–387).

Exoskeletons can assist the daily life activities of the elderly with weakened muscle strength, but traditional rigid exoskeletons bring parasitic torque to the human joints and easily disturbs the natural movement of the wearer’s upper limbs. Flexible exoskeletons have more natural human-machine interaction, lower weight and cost, and have great application potential. Applying assist force according to the patient’s needs can give full play to the wearer’s remaining muscle strength, which is more conducive to muscle strength training and motor function recovery. In this paper, a design scheme of an elbow exoskeleton driven by flexible antagonistic cable actuators is proposed. The cable actuator is driven by a nonlinear series elastic mechanism, in which the elastic elements simulate the passive elastic properties of human skeletal muscle. Based on an improved elbow musculoskeletal model, the assist torque of exoskeleton is predicted. An assist-as-needed (AAN) control algorithm is proposed for the exoskeleton and experiments are carried out. The experimental results on the experimental platform show that the root mean square error between the predicted assist torque and the actual assist torque is 0.00226 Nm. The wearing experimental results also show that the AAN control method designed in this paper can reduce the activation of biceps brachii effectively when the exoskeleton assist level increases.

Although impedance control has huge application potential in human–robot cooperation, its engineering application is still quite limited, owing to the high nonlinearity of the human–robot dynamics and disturbances. This article presents a novel adaptive neural network controller with extended state observer for the human–robot interaction using output feedback. The adaptive neural network with extended state observer integrates the adaptive neural network and extended state observer to combine their advantages. The proposed algorithm can address the challenges encountered in human–machine systems, for example, slow convergence of neural networks, internal and external disturbances. Output feedback is realized using tracking differentiator to avoid the costly measurements of certain states. The errors of the closed-loop system are proven to converge to a small compact set containing 0 by Lyapunov theory. Simulations and experiments were conducted to verify the effectiveness of the proposed controller. Results show that the proposed strategy offers superior convergence and better tracking performance compared with the adaptive neural network. The proposed controller can be widely applied in various human–machine interactions to enhance productivity and efficiency.

In selective ulnar and median nerve transfers, donor nerve fascicles should be harvested in an area where motor and sensory fascicles are intermingled to minimize motor or sensory deficits. We aimed to define such an area for ulnar and median nerve harvesting through microanatomical dissection and histology in 12 fresh adult cadaveric upper extremities. Anatomically, we studied the arrangement, localization, and histological features of fascicle groups in two nerves at eight segments of the upper arms. Histological sections were examined to confirm the findings of the anatomical dissections. We found that sensory and motor fascicles were mixed proximally to the third most distal segment of the ulnar nerve and to the fourth most distal segment of the median nerve. We conclude that harvesting a part of the ulnar or median nerve proximal to these levels minimizes donor nerve deficits.

Human gait involves activities in nervous and biomechanics of the musculoskeletal system. Thus, approaching the dynamics may be challenging. This paper aims to present the design of soft smart shoes for joint angle estimation in human gait. There are three pneumatic chambers at the heel, arch, and forefoot of the soft sole. Barometers embedded in every chambers are used to measure the ground reaction forces (GRFs). The inertial sensors are installed on the outsole of shoes to detect the foot attitudes. The soft soles are made of silicone rubber to provide good compliance and ensure the comfort of human. Gaussian process regression (GPR) is established and serves as the mathematics foundation to explore the deep layer correlation between the joint angle and GRFs and foot attitudes which are regarded as the inputs of the model. The statistic nature of the proposed model offers superior flexibility and encouraging estimation results of joint angles. One potential use of the novel designed shoes and the proposed joint estimation method is the high-level control of exoskeletons and prosthetic legs. Finally, experiments were conducted to verify the superiority of the proposed algorithms.

Purpose Complex injuries of the extremity can be very challenging to treat. In the setting of soft tissue infection and vascular defect, arterial reconstructions are at high risk of failure. Historically, there have not been good options to successfully salvage limbs with these serious injuries. We describe our experience of utilizing a cross limb vessel transfer to salvage the limb. Methods Patients were identified retrospectively with complex vascular injuries of the extremity and wound infection, who were treated with a cross limb vessel transfer. Once the infection has successfully been cleared, flow-through flap transfer was performed for definitive reconstruction of the arterial injury. Data collated included patient demographics, injury and operation details, and post-operative outcomes including blood supply of the limb, wound infection and complications. Results Between April 2014 and January 2017, 3 patients with an average age of 21 years (range, 16-29) were admitted. The median length of hospital stay was 62 days (range, 26-122). The average number of operation was 7.3 times (range, 6-10). Two patients’ upper limb had survived with limited movement, relatively minor donor site morbidity and confirmed flow through the vessel reconstruction using CTA, while one patient had lower limb amputation due to severe infection and prolonged ischemia time. Conclusions This series of patients demonstrates that cross limb vessel transfer is an invaluable technique to salvage the limb in patients with complex vascular injury and wound infection. However, for lower limb with prolonged ischemia time and severe infection, limb salvage is not recommended.

Continuous human motion intent learning may be modeled using a Gaussian process (GP) autoregression based evolving system to cope with the unspecified and time-varying motion patterns. Electromyography (EMG) signals are the primary input. GP is used as a mathematical foundation to model human kinematics by adopting the nonlinear autoregressive with exogenous inputs (NARX) framework, and an evolving system is applied to learn the irregular and unspecified dynamic features. The statistical nature of the GP offers superior flexibility for learning human kinematics and is capable of giving credibility to motion intent prediction, which also enables risk-based control. As an important neuromuscular signal, EMG is processed with a novel method, the energy kernel method, to extract the activation level of muscle and feature out muscular force and motion intent. Without losing robustness, the high signal-to-noise ratio or the linearity level with muscular force, huge improvement has been made in computational efficiency to meet the requirements of real-time applications. Experimental works concerning the validity and application of this method are also presented.

Understanding the distribution and composition of soil microbes in bare patches is a critical step to improving ecological remediation. The effects of different vegetative restoration types on soil microbes within semi‐arid bare patches remain unclear. Here, we evaluated the distribution of soil fungi and bacteria among different ecological restoration types at the southern Taihang Mountains. Analysis of variance showed that the chemical properties of soil with vegetation cover have higher nutrient quality than those of the exposed soil. The results also suggested that vegetative restoration significantly improved the diversity and the richness of the soil fungal and bacterial communities. Sequencing results showed that Ascomycota and Basidiomycota were the main soil fungal communities, whereas Proteobacteria, Acidobacteria, and Actinobacteria were the main soil bacterial communities. There were significant relationships between the contents of moisture, organic matter and organic carbon and the soil fungal/bacterial communities. Venn and network diagrams indicated that the vegetative restoration types largely influenced the soil fungi and weakly influenced the soil bacteria in the bare patches. This study discusses the importance of vegetative restoration in the ecological remediation of bare patches. These findings provide effective references for soil restorative measures, water conservation, and bare‐spot reduction at the southern Taihang Mountains in future., This study discusses the importance of vegetative restoration in the ecological remediation of bare patches. These findings provide effective references for soil restorative measures, water conservation, and bare‐spot reduction at the southern Taihang Mountains in future.

Direct coaptation of contralateral C7 to the upper trunk could avoid the interposition of nerve grafts. We have successfully shortened the gap and graft lengths, and even achieved direct coaptation. However, direct repair can only be performed in some selected cases, and partial procedures still require autografts, which are the gold standard for repairing neurologic defects. As symptoms often occur after autografting, human acellular nerve allografts have been used to avoid concomitant symptoms. This study investigated the quality of shoulder abduction and elbow flexion following direct repair and acellular allografting to evaluate issues requiring attention for brachial plexus injury repair. Fifty-one brachial plexus injury patients in the surgical database were eligible for this retrospective study. Patients were divided into two groups according to different surgical methods. Direct repair was performed in 27 patients, while acellular nerve allografts were used to bridge the gap between the contralateral C7 nerve root and upper trunk in 24 patients. The length of the harvested contralateral C7 nerve root was measured intraoperatively. Deltoid and biceps muscle strength, and degrees of shoulder abduction and elbow flexion were examined according to the British Medical Research Council scoring system; meaningful recovery was defined as M3-M5. Lengths of anterior and posterior divisions of the contralateral C7 in the direct repair group were 7.64 ± 0.69 mm and 7.55 ± 0.69 mm, respectively, and in the acellular nerve allografts group were 6.46 ± 0.58 mm and 6.43 ± 0.59 mm, respectively. After a minimum of 4-year follow-up, meaningful recoveries of deltoid and biceps muscles in the direct repair group were 88.89% and 85.19%, respectively, while they were 70.83% and 66.67% in the acellular nerve allografts group. Time to C5/C6 reinnervation was shorter in the direct repair group compared with the acellular nerve allografts group. Direct repair facilitated the restoration of shoulder abduction and elbow flexion. Thus, if direct coaptation is not possible, use of acellular nerve allografts is a suitable option. This study was approved by the Medical Ethical Committee of the First Affiliated Hospital of Sun Yat-sen University, China (Application ID: [2017] 290) on November 14, 2017.

A potting experiment was conducted to investigate the effect of sulfur application on the bioaccumulation by tobacco and its mechanisms of rhizospheric microorganisms. Cadmium content in tobacco was analyzed using atomic absorption spectrometer, while bacterial community and related gene in soil were analyzed via high-throughput sequencing and quantitative PCR techniques, respectively. The obtained results indicated that tobacco had the ability to accumulate cadmium under no sulfur application conditions, with cadmium contents of 35.4, 23.6, and 26.3 mg kg-1 in leaves, stems, and roots, respectively. Under high-sulfur treatment, these values increased to 66.4, 46.1, and 42.6 mg kg-1, respectively, probably due to the increase of the available cadmium content (from 1.1 to 3.3 mg kg-1) in the soil through a decrease of the soil pH value, which was contributed by the sulfur oxidation reaction. dsrA and soxB genes might play an important role in sulfur oxidation, and Thiobacillus sp. was the dominant bacterial genus during the sulfur oxidation process. In addition, sulfur application exerted little effect on the diversity and structure of the soil bacterial community. The combined results indicate that sulfur application is an effective and safe method for Cd phytoextraction by tobacco.

Background: The purpose of this study was to illustrate the characteristics of skeletal muscle ECM hydrogels and assess the function and underlying mechanisms of hydrogels combined with TGFβ1 for the myogenesis of skeletal muscle stem cells (SkMSCs). Methods: Six methods were used to obtain extracellular matrix (ECM) from rat skeletal muscle. Hydrogel components and cytocompatibility were assessed by Masson’s trichrome staining, scanning electron microscopy, the sulfated glycosaminoglycan (s-GAG) and bFGF contents and a cell viability assay. Satellite cells were sorted, identified and seeded into skeletal muscle ECM hydrogels with TGFβ1. To determine the function of decellularized aligned skeletal muscle ECM hydrogels with TGFβ1 for the proliferation and differentiation of SkMSCs, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, 5-ethynyl-2′-deoxyuridine (EdU) analysis and immunofluorescence staining were conducted. RNA stability assay and Gene set enrichment analysis (GSEA) were used to further investigated the mechanism underlying the function. Results: Our study established a highly efficient method for the decellularization of skeletal muscle and fabricated an ECM hydrogel without cell components that preserves the rich ECM composition. This hydrogel formed a three-dimensional microstructure and showed good biocompatibility. We found that the decellularized aligned ECM scaffold with TGFβ1 promoted SkMSC proliferation and suppressed SkMSC differentiation through extracellular signal-regulated kinase (ERK) signaling. Our study suggested that TGFβ1 increases the m6A methylation of the integrin mRNA 3’UTR, thereby inducing the phosphorylation of ERK and promoting SkMSCs proliferation and differentiation.Conclusions: Our study explored a highly efficient method for the decellularization of skeletal muscle and fabricated an ECM hydrogel with a three-dimensional microstructure and good biocompatibility. Furthermore, we demonstrated that decellularized aligned ECM scaffolds with TGFβ1 promoted SkMSC proliferation and differentiation through enhancing the m6A methylation of the integrin mRNA 3’UTR, which may serve as a potential therapeutic strategy for the acute and chronic muscle injuries

Transparent human-exoskeleton interaction requires accurate human joint angle and velocity learning which are regarded as human intent detection to cope with the unspecific and irregular kinematics and dynamics of the system. This paper attempts to address the limitations and deficiencies encountered by traditional methods which make it challengeable to figure out the natural relationships among the strongly coupled multi-source information from each of the human-exoskeleton subsystems. Dependent Gaussian process (DGP) based data fusion algorithm is established and serves as the mathematics foundation to explore the deep layer correlation among the human joint angle, interactive force and processed sEMG achieving satisfactory prediction results of joint angle. Gradient estimation model is then performed to obtain the human joint velocity by differential of a GP model. The statistic nature of the proposed model offers superior flexibility and encouraging human motion prediction results. And the proposed model can achieve human joint angle and velocity learning simultaneously without accessional sensors which may incur marked cost or may be impossible. Experimental works on an in-house exoskeleton which is the key step to verify the superiority of the proposed algorithms are also presented.

Additional file 2: Figure S2. (A) Elbow flexion and fingers and thumb extension reconstruction; (B). Fingers and thumb reconstruction.

Additional file 3: Table S1. Ultrasound and follow-up results of all 35 patients

Changes in precipitation patterns greatly impact regional drought/flood risk management and utilization of water resources. The main purpose of this paper was to investigate spatio-temporal variability of precipitation concentration in the transitional zone between Qinling Mountains (QDM), Guanzhong Plain (GZP) and the Loess Plateau (LPNS) in China, using monthly-scale precipitation concentration index (PCI) and daily-scale concentration index (CI) from daily rainfall records. The Mann-Kendall method was employed to illustrate the change in trend of PCI and CI, the Kriging interpolation method was adopted to measure spatial distribution, and the Wavelet transforms were used to explore their spatio-temporal correlation with the Arctic Oscillation (AO) & Western Pacific Subtropical High (WPSH) for revealing the potential attribution of precipitation concentration variation. Also, the regional implication of CI was investigated in the zone to provide local knowledge of the index application. Results showed that annual precipitation demonstrated a north-south increasing layered spatial distribution in the zone, representing a generally decreasing trend. The CI change generally exhibited a more significant decreasing trend than did PCI in LPNS and GZP due to AO slowly increasing over time, with a spatially weak layered or radial north-south decay, and an insignificant increasing trend in QDM impacted by the enhancing WPSH, with an obvious layered or radial spatial distribution. The spatiotemporal pattern of PCI variation represented similar characteristics in attribution with CI, but an inverse spatial distribution due to the phase difference (positive and negative effects) of AO and WPSH influencing seasonal precipitation. Regional analysis of CI showed that the CI value with over 0.62 indicated that approximately 80% of precipitation was contributed by 25% of the rainiest days in this zone. Fortunately, the area with this high CI has been getting smaller, implying a positive trend toward regional flash flood and debris flow control.

Background Lymphedema is a chronic disease results from impaired flow of the lymphatic system. Therefore, reconstruction of lymphatic system is crucial to treat limb lymphedema. Vascular endothelial growth factor (VEGFC) has been reported to be an important regulator involved in the growth and differentiation of lymphatic endothelial cells; however; the application of exosomes with VEGFC in the treatment of lymphedema has been rarely reported. Methods From the membrane-based fusion technology, we constructed engineered exosomes that overexpress CD63-VEGFC fusion protein (CD63-VEGFC/exos). We examined the in vitro effects of CD63-VEGFC/exos on the proliferation, migration, and tube formation of human dermal lymphatic endothelial cells (HDLECs) by MTT assay, migration assay, and tube formation assay, respectively. CD63-VEGFC/exos were embedded in sodium alginate hydrogel and their effect on lymphedema was evaluated by a mouse model. Results VEGFC could be successfully delivered to lymphatic endothelial cells via engineered CD63-VEGFC/exos. Treatment with CD63-VEGFC/exos resulted in a significant increase in the proliferation, migration, and tube formation of lymphatic endothelial cells. Using CD63-VEGFC/egos in sodium alginate hydrogel enabled a sequenced release of exosomes and markedly improved lymphedema in a mouse model. Conclusions Our findings supply a novel adipose tissue-derived stem cell (ADSC)-exo-based strategy that delivers target proteins to lymphatic endothelial cells and thus enhances the treatment of lymphedema.

Background: Ultrasonic measurement has not been utilized to assess functional recovery of transplanted muscle. This study aimed to investigate the feasibility of B-ultrasound measurement for evaluation of muscle recovery following free functioning gracilis transfer.Methods: From January 2009 to January 2014, 35 patients receiving free functioning gracilis transfer due to total brachial plexus injury were enrolled. B-ultrasound was utilized to measure the cross-sectional area (CSA) of transplanted gracilis muscle at rest and contraction state. The ratio of pre- to post-transplant CSA value at rest state was defined as muscle bulk ratio (MBR). The ratio of CSA value at the contraction state to that at rest state was defined as contraction ratio (CR). Results: Patients with muscle strength M≥4 had significantly higher CR1 (post-transplant), CR2 (pre-transplant), and range of motion (ROM, joint mobility) than those with muscle strength M＜4. The CR1>CR2 group had significantly higher CR1, muscle strength, and ROM than the CR1≤CR2 group. The MBR>1 group had significantly higher muscle strength than the MBR≤1 group. CR1 value was highly correlated with muscle strength and with ROM. CR2 value was moderately correlated with muscle strength and ROM. Multivariate linear regression analysis showed that higher CR1/CR2 value was associated with higher muscle strength and higher joint mobility. The CR1>CR2 group had better muscle strength and ROM than the CR1≤CR2 groups.Conclusion: B-ultrasound measurement can quantitatively reflect muscle strength following gracilis transfer, and CR but not MBR value could be a potential indicator for functional recovery of the transplanted gracilis muscle.Level of Evidence: Prognostic studies, Level II.

Estimating the joint torques of lower limbs in human gait is a highly challenging task and of great significance in developing high-level controllers for lower-limb exoskeletons. This paper presents a dependent Gaussian process (DGP)-based learning algorithm for joint-torque estimations with measurements from wearable smart shoes. The DGP was established to perform data fusion, and serves as the mathematical foundation to explore the correlations between joint kinematics and joint torques that are embedded deeply in the data. As joint kinematics are used in the training phase rather than the prediction process, the DGP model can realize accurate predictions in outdoor activities by using only the smart shoe, which is low-cost, nonintrusive for human gait, and comfortable to wearers. The design methodology of dynamic specific kernel functions is presented in accordance to prior knowledge of the measured signals. The designed composite kernel functions can be used to model multiple features at different scales, and cope with the temporal evolution of human gait. The statistical nature of the proposed DGP model and the composite kernel functions offer superior flexibility for time-varying gait-pattern learning, and enable accurate joint-torque estimations. Experiments were conducted with five subjects, whose results showed that it is possible to estimate joint torques under different trained and untrained speed levels. Comparisons were made between the proposed DGP and Gaussian process (GP) models. Obvious improvements were achieved when all DGP r2 values were higher than those of GP.