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Abstract Helicoid plasmonic nanoparticles with intrinsic chirality are an emerging class of artificial chiral materials with tailorable properties. The ability to extend their chiroplasmonic responses to the near-infrared (NIR) range is critically important for biomedical and nanophotonic applications, yet the rational design of such materials remains challenging. Herein, a strategy employing chiral plasmon-dielectric coupling is proposed to manipulate the chiroptical responses into the NIR region with high optical anisotropy. Through this strategy, the helicoid Au@Cu2O nanoparticles with structural chirality are designed and synthesized with tunable and enriched NIR chiroptical responses. Specially, a high optical anisotropy (g-factor) with a value of 0.35 is achieved in the NIR region, and multi-band chiroptical behaviors are observed. Spectral and electromagnetic simulations elucidate that strong coupling between chiroplasmonic core and chiral dielectric shell with high refractive index contributes to the rich and strong chiroptical responses, which are related to the interplay between various emerged and enhanced electric and magnetic multipolar resonance modes proved by multipole expansion analysis. Moreover, the helicoid Au@Cu2O nanoparticles display greater polarization rotation capability than the helicoid Au nanoparticles. This work offers mechanistic insights into chiral plasmon-dielectric coupling and suggests a general approach of creating NIR chiroplasmonic materials.

ObjectiveTo explore the neuromuscular control mechanism and quantifying the fatigue response during bench press exercise is important references to prescribe an appropriate exercise program. However, current literature struggles to provide a concrete conclusion on the changes of intermuscular EMG-EMG coupling between synergistic and antagonist muscles during the exercise. Thus, the current study was designed to reveal fatigue-related changes of intermuscular EMG-EMG coupling during bench press exercise.MethodsThirty-one healthy male participants performed a bench press exercise on the Smith machine at 60% One Repetition Maximum (1RM) workload to exhaustion, while surface electromyographic signals (sEMG) were collected from triceps brachii (TB), biceps brachii (BB), anterior deltoid (AD), posterior deltoid (PD), and pectoralis major (PM). Surface EMG signals were divided into the first half and second half of the bench press exercise. Phase synchronization index (PSI) was calculated between sEMG of synergistic muscle pairs AD-TB, AD-PM and antagonist muscle pairs BB-TB, AD-PD.ResultsEMG power of TB, AD, PD, PM muscles in alpha (8–12 Hz) frequency band and EMG power of each muscle in beta (15–35 Hz), and gamma (35–60 Hz) frequency bands were all increased during the second half of contraction compared with the first half of contraction. PSI of gamma frequency band was significantly decreased in BB-TB muscle pair while EMG-EMG coupling of AD-TB in gamma frequency band was significantly increased during the second half of contraction compared to the first half of contraction.ConclusionsThe results indicated a decrease of interconnection between synchronized cortical neurons and the motoneuron pool of BB and TB, and an increase of interconnection between AD-TB muscles during fatiguing bench press exercise at 60% 1RM workload. The changes of intermuscular coupling may be related to the supraspinal modulations to compensate for the decrease of muscle force as well as a result of unbalanced changes of agonist and antagonist muscle contractility.

Abstract Background Near infrared brain functional imaging (FNIRS) has been used for the evaluation of brain functional areas, the imaging differences of central activation of cognitive-motor dual tasks between patients with chronic lateral ankle instability (CLAI) and healthy population remain unclear. This study aimed to evaluated the role of central imaging based on FNIRS technology on the plan management in patients with CLAI, to provide insights to the clinical treatment of CLAI. Methods CLAI patients treated in our hospital from January 1, 2021 to June 31, 2022 were selected. Both CLAI patients and health controls were intervened with simple task and cognitive-motor dual task under sitting and walking conditions, and the changes of oxygenated hemoglobin concentration in bilateral prefrontal cortex (PFC), premotor cortex (PMC) and auxiliary motor area (SMA) were collected and compared. Results A total of 23 participants were enrolled. There were significant differences in the fNIRS ΔHbO2 of barefoot subtractive walking PFC-R and barefoot subtractive walking SMA-R between experimental and control group (all P 0.05). There was no significant difference in ΔHbO2 between the experimental group and the control group in each state of the brain PMC region. Conclusion Adaptive alterations may occur within the relevant brain functional regions of individuals with CLAI. The differential activation observed between the PFC and the SMA could represent a compensatory mechanism emerging from proprioceptive afferent disruptions following an initial ankle sprain.

In the dynamic interaction between the runner and the ground, the running shoe is the only medium that bears the impact force of body weight and plays a crucial role in athletic performance. Traditional designs do not adequately consider the different shapes of the foot, which often leads to discomfort and aggravation of foot disorders. This study presents an innovative approach to running shoe midsole design using 3D-printed chiral negative poisson’s ratio (NPR) structures to enhance shock absorption and support, thereby optimizing biomechanical performance and comfort. Using computer-aided design (CAD) and computer-aided engineering (CAE), the biomechanical effects of different midsole structures has been explored through finite element analysis (FEA). The study focuses on optimizing the cushioning, propulsion and stability of the midsole to mitigate the impact on the ankle and knee. Static compression and dynamic impact simulations were utilized to comprehensively select optimized design of midsole structure and the selected structures was 3D printed to validate the biomechanical benefits in a wear trial. The results of the study highlight the superior performance of chiral NPR structures in reducing forefoot stress during standing and movement and advance the design and functionality of 3D printed materials in running shoes.

IntroductionOsteoporosis-induced changes in bone structure and composition significantly reduce bone strength, particularly in the human proximal femur. This study examines how these changes affect the mechanical performance of trabecular bone to enhance diagnosis, prevention, and treatment strategies.MethodsA proximal femur sample was scanned using micro-CT at 40 μm resolution. Five regions of interest were selected within the femoral head, femoral neck, and greater trochanter. Structural models simulating various stages of osteoporosis were created using image processing software. Micro-finite element analysis evaluated the mechanical properties of trabecular bone under different conditions of structural deterioration and tissue-level elastic modulus variations. The combined effects of structural deterioration and tissue-level mechanical properties on trabecular bone mechanical performance were further analyzed.ResultsThe mechanical performance of trabecular bone generally follows a power-law relationship with its microstructural characteristics. However, in any specific region, the apparent mechanical properties linearly decrease with structural deterioration. The femoral neck and greater trochanter are more sensitive to structural deterioration than the femoral head. A 5% bone mass loss in the femoral head led to a 7% reduction in mechanical performance, while the femoral neck experienced a 12% loss. Increasing tissue-level elastic modulus improved mechanical performance, partially offsetting bone mass reduction effects.ConclusionTrabecular bone in low bone mass regions is more affected by bone mass loss. Structural deterioration primarily reduces bone strength, but improvements in tissue-level properties can mitigate this effect, especially in early osteoporosis. Targeted assessments and interventions are crucial for effective management. Future research should explore heterogeneous deterioration models to better understand osteoporosis progression.

BackgroundMetatarsal stress fracture is common in people engaged in repetitive weight-bearing activities, especially athletes and recruits. Identifying risk factors in these contexts is crucial for effective prevention.MethodsA systematic search on Web of Science, PubMed, EBSCO, SPORTDiscus, MEDLINE, and Cochrane Library was conducted and the date range for the retrieval was set from January 1984 to April 2024.Results32 eligible studies were selected from 1,728 related research. Anatomical and biomechanical factors, such as higher foot arch, abnormal inversion/eversion of foot, and longer metatarsal length or larger angles, relatively influence stress fracture risk. However, given that there is no standardized measurement, the results remain to be examined. Soccer is associated with fifth metatarsal fractures, while long-distance running and recruit training often lead to fractures of the second or third metatarsals. High exercise intensity, non-adaptive training, and inadequate equipment heighten fracture risk.ConclusionThis review highlights the complex interplay of anatomical, biomechanical, and sports-related factors in the risk of metatarsal stress fractures. Relatively, high arches, specific metatarsal morphologies, and foot inversion/eversion patterns are significant risk factors, particularly among athletes. Sports type also correlates with metatarsal stress fracture locations. Despite extensive research, study heterogeneity and inherent biases necessitate cautious interpretation. Comprehensive, multifactorial approaches and personalized injury prevention strategies are essential for reducing the incidence of these injuries and improving the health and performance of athletes.

Summary: The monitoring of treadmill walking energy expenditure (EE) plays an important role in health evaluations and management, particularly in older individuals and those with chronic diseases. However, universal and highly accurate prediction methods for walking EE are still lacking. In this paper, we propose an ensemble neural network (ENN) model that predicts the treadmill walking EE of younger and older adults and stroke survivors with high precision based on easy-to-obtain features. Compared with previous studies, the proposed model reduced the estimation error by 13.95% and 66.20% for stroke survivors and younger adults, respectively. Furthermore, a contactless monitoring system was developed based on Kinect, mm-wave radar, and ENN algorithms, and the treadmill walking EE was monitored in real time. This ENN model and monitoring system can be combined with smart devices and treadmill, making them suitable for evaluating, monitoring, and tracking changes in health during exercise and in rehabilitation environments.

Abstract Background Wheelchair Tai Chi (WCTC) has been proved to have benefits for the brain and motor system of spinal cord injury (SCI) patients. However, the characteristics of corticomuscular coupling during WCTC are scarcely known. We aimed to investigate changes following SCI on corticomuscular coupling, and further compare the coupling characteristics of WCTC with aerobic exercise in SCI patients. Methods A total of 15 SCI patients and 25 healthy controls were recruited. The patients had to perform aerobic exercise and WCTC, while healthy controls needed to complete a set of WCTC. The participants accomplished the test following the tutorial video in a sitting position. The upper limb muscle activation was measured from upper trapezius, medial deltoid, biceps brachii and triceps brachii with surface electromyography. Cortical activity in the prefrontal cortex, premotor cortex, supplementary motor area and primary motor cortex was simultaneously collected by functional near-infrared spectroscopy. The functional connectivity, phase synchronization index and coherence values were then calculated and statistically analyzed. Results Compared to healthy controls, changes in functional connectivity and higher muscle activation were observed in the SCI group. There was no significant difference in phase synchronization between groups. Among patients, significantly higher coherence values between the left biceps brachii as well as the right triceps brachii and contralateral regions of interest were found during WCTC than during aerobic exercise. Conclusion The patients may compensate for the lack of corticomuscular coupling by enhancing muscle activation. This study demonstrated the potential and advantages of WCTC in eliciting corticomuscular coupling, which may optimize rehabilitation following SCI.

The present study was aimed to verify whether an integrating of wearable activity tracker device and a social media intervention strategy would be better than a standalone social media intervention for improving physical activity (PA) and reducing sedentary time for Chinese postgraduate population. A total of 42 full-time postgraduate students participated in this study, which were randomized to receive a 4-week social media intervention through WeChat either with (Wearable Device group) or without (control group) a wearable activity tracker device. Energy expenditure, step counts, moderate to vigorous physical activity time (MVPA) and sedentary time were assessed before and after the intervention. Besides, anthropometric parameters of body weight, body mass index, body fat rate, waist-to-hip ratio, as well as self-reported quality of life were also evaluated. It was found that both energy expenditure and step counts were significantly increased, while sedentary time was significantly reduced during the post-intervention test compared to the baseline test for Wearable Device group. No significant difference of PA was found for the control group. The results demonstrated that the integrating of wearable activity tracker device and a social media intervention was effective in promoting PA, while a standalone social media intervention may have no effect on the influence of PA for Chinese postgraduates.

The foot, as the foundation of the human body, bears the vast majority of the body’s weight. Obese children bear more weight than healthy children in the process of walking and running. This study compared three footwear midsole structures (solid, lattice, and chiral) based on plantar pressure distribution and bone stress in obese and healthy children through numerical simulation. The preparation for the study included obtaining a thin-slice CT scan of a healthy 9-year-old boy’s right foot, and this study distinguished between a healthy and an obese child by applying external loadings of 25 kg and 50 kg in the finite element models. The simulation results showed that the plantar pressure was mainly concentrated in the forefoot and heel due to the distribution of gravity (first metatarsal, fourth metatarsal, and heel bone, corresponding to plantar regions M1, M4, and HM and HL) on the foot in normal standing. Compared with the lattice and solid EVA structures, in both healthy and obese children, the percentage reduction in plantar pressure due to the chiral structure in the areas M1, M4, HM, and HL was the largest with values of 38.69%, 34.25%, 64.24%, and 54.03% for an obese child and 33.99%, 28.25%, 56.08%, and 56.96% for a healthy child. On the other hand, higher pressures (15.19 kPa for an obese child and 5.42 kPa for a healthy child) were observed in the MF area when using the chiral structure than when using the other two structures, which means that this structure can transfer an amount of pressure from the heel to the arch, resulting in a release in the pressure at the heel region and providing support at the arch. In addition, the study found that the chiral structure was not highly sensitive to the external application of body weight. This indicates that the chiral structure is more stable than the other two structures and is minimally affected by changes in external conditions. The findings in this research lay the groundwork for clinical prevention and intervention in foot disorders in obese children and provide new research ideas for shoe midsole manufacturers.

The aim of this study was to examine whether antagonist muscles may be fatigued during a prolonged isometric fatiguing elbow flexion at very low forces. Twelve healthy male subjects sustained an isometric elbow flexion at 10% maximal voluntary contraction torque until exhaustion while multichannel electromyographic signals were collected from the biceps brachii (BB) and triceps brachii (TB). Muscle fiber conduction velocity (CV) and fractal dimension (FD) of both muscles were calculated to reflect peripheral and central fatigue. CV and FD of TB as well as FD of BB decreased progressively during the sustained fatiguing contraction, while the CV of BB declined at the beginning of the contraction and then increased progressively until the end of the contraction. The result may indicate that during the sustained low-force isometric fatiguing contraction, antagonist muscle may be peripherally fatigued, and changes in coactivation activities were modulated not only by central neuronal mechanisms of common drive but also by peripheral metabolic factors.

As a markerless motion capture system (MLS), the Microsoft Kinect sensor may be a low-cost and portable option for measuring shoulder joint angles. However, the system's concurrent validity to capture shoulder functional movement is unclear. The purpose of this study was to investigate the concurrent validity of MLS for capturing shoulder kinematics during functional movement by comparing the MLS measures to those of the marker-based motion capture system (MBS). Twenty-five healthy participants were included in this study. Using the Microsoft Kinect sensor as the MLS and Vicon as the MBS, six shoulder functional movements were measured in all three anatomical planes concurrently. The six movements included flexion to max, maximum extension, abduction to 90°, internal rotation at 90° abduction, external rotation at 0° abduction, and maximum horizontal adduction. The shoulder joint kinematics was measured with both systems. The MLS showed a good to excellent correlation (r ​> ​0.75) with MBS for abduction to 90°, maximum external rotation at 0° abduction and maximum internal rotation at 90° abduction. The results for maximum extension (r ​= ​0.727) and maximum horizontal adduction (r ​= ​0.619) showed a moderate to good correlation. For maximum flexion, a poor correlation was observed (r ​= ​0.479). The validity of the MLS to measure shoulder kinematics would be acceptable. The system demonstrates potential as a measurement tool of joint motions for a function assessment and rehabilitation purpose.

The aim of this study was to analyze and compare the muscle activation and concomitant intermuscular coupling of antagonist muscles among bench presses with different instability degrees. Twenty-nine untrained male college students performed bench press exercises at an intensity of 60% 1 RM on three conditions: small unstable bench press with Smith machine (SBP), medium unstable bench press of free weight (FWBP), and large unstable bench press with increased instability by suspending the load with elastic bands (IIBP). One-way repeated measures analysis of variance was used to compare integrated EMG activity values of the biceps brachii (BB), posterior deltoid (PD), long head of the triceps brachii (TB), anterior deltoid (AD), upper portion of the pectoralis major (PM) muscles, and phase synchronization index (PSI) of BB-TB and PD-AD antagonist muscle pairs. A higher integrated EMG of BB muscle was found during bench press with a more unstable condition. IIBP showed a higher integrated EMG of prime movers (TB, AD, and PM) and stabilizing of BB than SBP and FWBP. PSI between muscle pairs of BB-TB in the gamma frequency band was higher in SBP than the other bench presses with unstable conditions, which may be related to the optimal “internal model” for antagonist muscles during bench press exercise. Therefore, IIBP training may be an effective accessory exercise to maintain a higher level of muscle activation across primary and stabilizing muscles with a lighter load for untrained men, while SBP may be a suitable bench press exercise for untrained participants who have not developed the neuromuscular adaptations necessary for correct stabilization of the elbow joint.

ObjectiveWe created predictive models using machine learning algorithms for return-to-work (RTW) in patients with traumatic upper extremity injuries.MethodsData were obtained immediately before patient discharge and patients were followed up for 1 year. K-nearest neighbor, logistic regression, support vector machine, and decision tree algorithms were used to create our predictive models for RTW.ResultsIn total, 163 patients with traumatic upper extremity injury were enrolled, and 107/163 (65.6%) had successfully returned to work at 1-year of follow-up. The decision tree model had a lower F1-score than any of the other models (t values: 7.93–8.67, p < 0.001), while the others had comparable F1-scores. Furthermore, the logistic regression and support vector machine models were significantly superior to the k-nearest neighbors and decision tree models in the area under the receiver operating characteristic curve (t values: 6.64–13.71, p < 0.001). Compared with the support vector machine, logistical regression selected only two essential factors, namely, the patient's expectation of RTW and carrying strength at the waist, suggesting its superior efficiency in the prediction of RTW.ConclusionOur study demonstrated that high predictability for RTW can be achieved through use of machine learning models, which is helpful development of individualized vocational rehabilitation strategies and relevant policymaking.

Background: Subtalar arthroereisis may cause sinus tarsi pain complications. In this study, we aimed to introduce a customised implant that facilitated treatment effect and less impingement. The biomechanical outcome between the intact and implant conditions was compared using finite element analysis. Methods: A female patient with flatfoot (age: 36 years, height: 156 ​cm, body mass: 51 ​kg) was recruited as the model patient. The customised implant was designed from the extracted geometry. Boundary and loading conditions were assumed from the data of a normal participant. Four gait instants, including the ground reaction force first peak (25% stance), valley (45%), initial push-off (60%) and second peak (75%) were analyzed. Results: The navicular height was elevated by 4.2% at 25% stance, whereas the strain of the spring, plantar cuneonavicular and plantar cuboideonavicular ligaments were reduced. The talonavicular joint force decreased and the calcaneocuboid joint increased by half and 67%, respectively, representing a lateralised load pathway. There was a stress concentration at the sulcus tali reaching 15.29 ​MPa Conclusion: Subtalar arthroereisis using a customised implant may produce some positive treatment effects in terms of navicular height elevation, ligament strain relief and lateralised joint loading pathway. Although the concentrated stress at the sulcus tali did not exceed the threshold of bone breakdown, we could not rule out the potential of vascular disturbance owing to the remarkable elevation of stress. Future study may enlarge the contact area of the bone–implant interface by considering customisation based on the dynamic change of the sinus tarsi during walking gait. The translational potential of this article: Geometry mismatch of prefabricated implants could be the reason for complications. With the advancement of 3D printing, customising implant becomes possible and may improve treatment outcome. This study implemented a theoretical model approach to explore its potential under a simulation of walking.

The crystal phase-based heterostructures of noble metal nanomaterials are of interest for various applications. Here, the authors report the wet-chemical synthesis of gold nanorods with a well-defined fcc-2H-fcc heterophase, which possess unique optical and catalytic properties.

The present study examined the effects of transcranial direct current stimulation (tDCS) using Halo Sport on the time to exhaustion (TTE) in relation with muscle activities and corticomuscular coupling of agonist and antagonist muscles during a sustained isometric fatiguing contraction performed with the elbow flexors. Twenty healthy male college students were randomly assigned to tDCS group and control group. The two group participants performed two experimental sessions which consisted of pre-fatigue isometric maximal voluntary contraction (MVC), sustained submaximal voluntary contractions (30% maximal torque) performed to exhaustion, and post-fatigue MVC with the right elbow flexor muscles. Sham stimulation (90 s) and tDCS (20 min) were applied for control and tDCS group participants 20 min prior to the second session test, respectively. MVC strength in pre- and post-fatigue test, TTE, electroencephalogram (EEG), and electromyography (EMG) of biceps brachii (BB) and triceps brachii (TB) were recorded during the tests. It was found that tDCS using the Halo Sport device significantly increased TTE and thus improved muscular endurance performance. The improvement may be partly related to the improvement of neuromuscular efficiency as reflected by decrease of antagonistic muscle coactivation activities, which may be related to cortical originated central processing mechanism of neuromuscular activities.

Background: The role of multifidus in the biomechanics of lumbar spine remained unclear. Purpose: This study aimed to investigate the role of multifidus in the modeling of lumbar spine and the influence of asymmetric multifidus atrophy on the biomechanics of lumbar spine. Methods: This study considered five different multifidus conditions in the trunk musculoskeletal models: group 1 (with entire multifidus), group 2 (without multifidus), group 3 (multifidus with half of maximum isometric force), group 4 (asymmetric multifidus atrophy on L5/S1 level), and group 5 (asymmetric multifidus atrophy on L4/L5 level). In order to test how different multifidus situations would affect the lumbar spine, four trunk flexional angles (0°, 30°, 60°, and 90°) were simulated. The calculation of muscle activation and muscle force was done using static optimization function in OpenSim. Then, joint reaction forces of L5/S1 and L4/L5 levels were calculated and compared among the groups. Results: The models without multifidus had the highest normalized compressive forces on the L4/L5 level in trunk flexion tasks. In extreme cases produced by group 2 models, the normalized compressive forces on L4/L5 level were 444% (30° flexion), 568% (60° flexion), and 576% (90° flexion) of upper body weight, which were 1.82 times, 1.63 times, and 1.13 times as large as the values computed by the corresponding models in group 1. In 90° flexion, the success rate of simulation in group 2 was 49.6%, followed by group 3 (84.4%), group 4 (89.6%), group 5 (92.8%), and group 1 (92.8%). Conclusions: The results demonstrate that incorporating multifidus in the musculoskeletal model is important for increasing the success rate of simulation and decreasing the incidence of overestimation of compressive load on the lumbar spine. Asymmetric multifidus atrophy has negligible effect on the lower lumbar spine in the trunk flexion posture. The results highlighted the fine-tuning ability of multifidus in equilibrating the loads on the lower back and the necessity of incorporating multifidus in trunk musculoskeletal modeling.

The methodological quality of subject-specific finite element analysis papers depends on the rigor of the study design and detailed description of key elements, while assessment instruments are often confined to clinical trials or quasi-experiments. This study aims to present an instrument for methodological quality assessment of single-subject finite element analysis used in computational orthopaedics (MQSSFE). Based upon existing instruments and relevant review papers, a pilot version was developed consisting of 37 items with 6 domains, including study design and presentation of findings, subject recruitment, model reconstruction and configuration, boundary and loading conditions (simulation), model verification and validation, and model assumption and validity. We interviewed four experts in the field to assess the face validity and refined the instrument. The instrument was tested for interrater reliability among two assessors on nine finite element study papers. Also, the criterion validity was evaluated by comparing the similarity of the MQSSFE and the modified Down and Black instrument. The intraclass correlation coefficient was 0.965, while the MQSSFE was significantly moderately correlated with the modified Down and Black instruments (r ​= ​0.61). We believed that MQSSFE was adequately appropriate, reliable, and valid for assessing the methodological quality for finite element studies used in computational orthopaedics. The instrument could facilitate quality assessment in the systematic reviews of finite element models and checklists for fidelity.

It has been demonstrated that articular facet degeneration can cause local strain alterations and induce neck pain. This study aims to quantify the biomechanical effects of normal and degenerated C5–C6 articular facets, and evaluate the correlation of mechanical strain between healthy and degenerated spine. A 3-dimensional finite element (FE) model of the C5–C6 cervical spine was developed [Model 0 (M0)]. The asymmetric models of C5–C6 bilateral articular facet joint were established separately to mimic articular facet joint degeneration. The capsule ligament stiffness of C5–C6 unilateral facet joint was altered with minimum and maximum threshold to simulate capsule ligaments' lesion and calcification [Model 1 (M1) and Model 2 (M2), respectively]. Besides, the cervical C5–C6 unilateral articular facet joint direction was changed by 5° and 10° forward to imitate the moderate joint hyperplasia and severe osteophyte (Model 3 and Model 4 respectively). M1 increased the rotation range of ipsilateral side (left), while M2 reduced, and both had limited effect on the contralateral side (right). The angle increased in Model 3 (M3) (61°) and Model 4 (M4) (55°) comparing to M0 during the axial rotation, and the angle of M4 was larger. M3 and M4 increased the nucleus pulposus pressure with and without controlled angular displacement during axial rotation. The pressure of nucleus pulpous increased during M1 rotating to the abnormal side but decreased when rotating to the other side, but the results of M2 were opposite. The capsule ligament stiffness made an impact on segmental mobility and vertebral spatial position, and the sagittal angle of articular facet joint exerted an influence on disc pressure distribution.

Twinning is a powerful approach to engineering the physicochemical properties of metallic nanomaterials. Here, the authors discover unusual non-close-packed twinning planes in 4H-phase gold nanokites and show that they can be used as templates to grow 4H-phase twinned nanostructures of other noble metals.

Abstract Background Grip strength (GS) test is an essential aspect of clinical practice with patients with upper extremity injuries. The random error of GS test was hypothesized to be proportional to the level of GS. The purpose of the current study was to estimate a precise range for the measurement error of GS in patients following traumatic injuries in the upper extremity. Methods Following traumatic injuries in the upper extremity, 109 participants completed GS tests twice one weekend apart. The Bland-Altman plot analysis was adopted to estimate the precise limits of agreement with 95% confidence interval (CI). Results The mean of three consecutive trials had a higher intraclass correlation coefficient of 0.974 (95% CI = 0.963, 0.982) than those of one trial and the mean of the first two trials in injured upper extremities. When GS was ≤20 kg, the upper limit of agreement with 95% CI was estimated as (0.41 × average GS + 1.24), while the lower limit was estimated as (− 0.41 × average GS − 0.39). A table of one-to-one matches between averaged GS ≤ 20 kg and transformed ranges of random errors with 95% certainty was created; the standard error of measurement and minimal detectable change with 95% certainty of GS test were 1.8 and 4.9 kg, respectively. When GS was > 20 kg, the width of agreement with 95% CI ranged from − 4.9 to 5.3 kg, and the standard error of measurement and minimal detectable change with 95% certainty were 1.8 and 5.1 kg, respectively. Conclusion The one-to-one match table can be considered as a practical tool to judge a change in GS score is real or due to random errors when it is ≤20 kg.

This study aimed to analyze the biomechanical response of the knee cartilage and meniscus to a typical Tai Chi (TC) movement, brush-knee and twist-step (BKTS). Kinematic and kinetic data was recorded while an experienced TC practitioner performed normal walking, jogging and BKTS. The kinetic data were then imported into a validated finite element model of the knee joint to examine the biomechanical response of the articular cartilage and meniscus. Compared with walking and jogging, the BKTS movement showed a greater increase in the range of motion (ROM) of the knee. The ROM in the sagittal plane was 56° (walking), 38° (jogging) and 93° (BKTS). In coronal plane, the knee ROM was 8° (walking), 11° (jogging) and 28° (BKTS). And in horizontal plane the ROM was 17° (walking), 15° (jogging) and 29° (BKTS). The finite element simulation demonstrated that the pressure contact stress is much more concentrated during walking and jogging than BKTS, which is consistent with the lower peak contact stresses recorded on the cartilage and meniscus. In conclusion, the TC movement produced a gentler stress state on the meniscus and cartilage, while also requiring a greater knee ROM. Practicing TC may have a lower risk of knee joint injury compared to walking and jogging.

Overexpression of reactive oxygen species (ROS) can lead to chronic inflammation, which limits skin wound healing. Therefore, it is of great significance to develop materials that can locally control the adverse reactions caused by excessive ROS. In this research, an ROS-sensitive hydrogel with strong free radical scavenging ability was prepared by introducing the thione (Tk) group into carboxymethyl chitosan (CMCTS) hydrogel. CMCTS hydrogel was cross-linked by NH2-Tk-NH2 agent and loaded curcumin (Cur), which possessed favorable nontoxicity, water absorption, mechanical property, biodegradability, drug release behavior, the M2 phenotype, and inflammatory factor regulating the capacity of macrophages. It is worth noting that Cur@CMCTS-Tk hydrogel can significantly inhibit oxidative damage of human fibroblasts in the H2O2-induced microenvironment and protect their viability by reducing the production of intracellular ROS. In vivo, ROS-removing hydrogel effectively accelerated the process of wound healing and possessed good regenerative properties, including hair follicle formation, promotion of new blood vessel formation, and highly orderly arrangement of collagen fibers in the full-thickness skin burn defect rat model. Hence, we expect that the Cur@CMCTS-Tk hydrogel could be used for wound treatment and tissue regeneration due to the ability to scavenge excess ROS.

Abstract Background Calcaneal fractures account for around 2% of all fractures and most of them are intra-articular fractures. Many implants have been used in the fixation of calcaneal fractures, but their biomechanical stability has not yet been well investigated. The aim of this study was to compare the primary stability of four fixations of calcaneal fracture. Methods Eight cadaveric calcaneus samples were used to simulate the Sanders’ types III fracture pattern and fixed through four different implants, namely, K-wires, cannulated screws (CS), absorbable screws (AS), and plate-screw system (PSS). Each specimen was then placed into a custom-made jig and was loaded through a material testing machine to simulate the physiological condition. The primary stability was measured in the vertical direction as the stiffness and anterior–posterior direction as the calcaneocuboid force. One-way analysis of variance was used for data analysis. Results The results showed the highest stiffness of 634 (383–891; SD 226) N/mm in the intact model. It was significantly higher than the models fixed with K-wires, CS or PSS. There was no significant difference in vertical stiffness between fractures fixed with AS and the intact model or other fixed models. The intact model showed the lowest calcaneocuboid force of 153 (120–218; SD 39) N, while the fractures fixed with AS showed the greatest force of 242 (146–398; SD 84) N. The significance was only detected between these two models. Conclusions The global stiffness was similar when the calcaneal fractures were fixed by K-wires, CS and PSS. The stability of the AS fixation differed along both the vertical and anterior–posterior directions, and was greatly influenced by the bone quality. AS for fracture fixation should be designed with greater strength and pull-out resistance.

Robotic technologies offer a range of functions to augment clinical rehabilitation practice. However, compliance with robot-assisted rehabilitation techniques has not been optimally achieved. Traditional approaches to improving the treatment efficacy are focusing more on the system function, while psychological factors have not been integrated comprehensively. In this perspective paper, eight key factors reflecting three conceptions-robot design, function design, and patients’ expectations have been evaluated and analyzed. Clinical results with 28 therapists and 84 patients indicate that integrating psychological strategies into robot-assisted physiotherapy may promote better trust and acceptance of rehabilitation robots.

Objective: The aim of this trial was to compare the effect of movement-based mirror therapy (MMT) and task-based mirror therapy (TMT) on improving upper limb functions in patients with stroke.Methods: A total of 34 patients with sub-acute stroke with mildly to moderately impaired upper limb motor functions. The participants were randomly allocated to one of three groups: MMT, TMT, and conventional treatment (CT). The MMT group underwent movement-based mirror therapy for around 30 min/day, 5 days/week, for 4 weeks, whereas the TMT group underwent dose-matched TMT. The CT group underwent only conventional rehabilitation. The MMT and TMT groups underwent CT in addition to their mirror therapy. Blinded assessments were administered at baseline and immediately after the intervention. Upper limb motor functions, measured using Fugl-Meyer Assessment-upper extremity (FMA-UE), Wolf Motor Function Test (WMFT), and hand grip strength; upper limb spasticity, measured using the modified Ashworth scale (MAS); and activities of daily living, measured using the modified Barthel index (MBI).Results: A significant time-by-group interaction effect was noted in FMA-UE. Post-hoc analysis of change scores showed that MMT yielded a better effect on improving FMA-UE than the other two therapies, at a marginally significant level (P = 0.050 and 0.022, respectively). No significant interaction effect was noted in WMFT, hand grip strength, MAS, and MBI.Conclusion: Both MMT and TMT are effective in improving the upper limb function of patients with mild to moderate hemiplegia due to stroke. Nevertheless, MMT seems to be superior to TMT in improving hemiplegic upper extremity impairment. Further studies with larger stroke cohorts are expected to be inspired by this pilot trial.Trial registration number: No. ChiCTR1800019043 (http://www.chictr.org.cn/index.aspx)

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INTRODUCTION:Foot and ankle impact injury is common in geriatric trauma and often leads to fracture of rearfoot, including calcaneus and talus. The objective of this study was to assess the influence of foot impact on the risk of calcaneus and talus fracture via finite element analysis. METHODS:A three-dimensional finite element model of foot and ankle was constructed based on magnetic resonance images of a female aged 28. The foot sustained a 7-kg passive impact through a foot plate. The simulated impact velocities were from 2.0 to 7.0 m/s with 1.0 m/s interval. RESULTS:At 5.0 m/s impact velocity, the maximum von Mises stress of the trabecular calcaneus and talus were 3.21MPa and 2.41MPa respectively, while that of the Tresca stress were 3.46MPa and 2.55MPa. About 94% and 84% of the trabecular calcaneus and talus exceeded the shear yielding stress, while 21.7% and 18.3% yielded the compressive stress. The peak stresses were distributed around the talocalcaneal articulation and the calcaneal tuberosity inferiorly, which corresponded to the common fracture sites. CONCLUSIONS:The prediction in this study showed that axial compressive impact at 5.0 m/s could produce considerable yielding of trabecular bone in both calcaneus and talus, dominantly by shear and compounded with compression that predispose the rearfoot in the risk of fracture. This study suggested the injury pattern and fracture mode of high energy trauma that provides insights in injury prevention and fracture management.

Background. The biomechanical effect of two implants, namely, proximal femoral nail antirotation for Asia (PFNA-II) and Expert Asian Femoral Nail (A2FN), for treating subtrochanteric fracture during healing stages, is still unclear. Methods. A 3D finite element model of an intact femur was constructed and validated. The fractured and postoperative models were accordingly produced. The postoperative models were loaded with the peak joint forces during gait for the soft and hard callus stages. The effects of stress distribution on the implants, femoral head and callus, and the deformation of the proximal femur were examined. Results. Both implants showed similar biomechanical effect in two healing stages. As the healing duration increased, the von Mises stress of two implants and the tensile stress of the femoral head decreased, whereas the compressive stress of the femoral head increased. However, the PFNA-II operation resulted in higher stress on the implant, lower stress on the proximal femur, and lower compressive stress and higher tensile stress on the callus than A2FN operation. Conclusions. The A2FN implant may provide a biomechanically superior construct for subtrochanteric fracture healing. However, the upper screw of the A2FN implant may be more likely to be loose in the healing process.

BACKGROUND: Primary health care and patient triage are two basic functions of rural hospitals. As a routine test, the diagnostic radiology is still unavailable in some rural hospitals in China. Therefore, high-level hospitals are often the first choice of rural residents when they feel unwell. It brings serious social problems. This study was designed to propose an on-the-job drilling schema with integration of practical medical recordings and experienced radiological doctors as tutors to improve skills in diagnostic radiology of rural physicians. METHODS: The information technology was used to help the contact between rural doctors and tutors. In a longitudinal pre/post-test control study design, a cohort of 20 young physicians, each of whom was working in a rural hospital and had a work experience less than two years, were established as the trial group over one year. Another 20 similar counterparts were established as the control group. Participants' performances were evaluated in four categories at five-time point (TP). RESULTS: The trial group significantly outscored the control group on the style of writing at the second TP (d = 2.28); on the accuracy of the image description at final TP (d = 1.11); on the accuracy of the diagnosis at the fourth TP (d = 3.62); and on the correct treatment selection at the third TP (d = 6.45). The aspects with the most improvement were the accuracies of the diagnosis and the treatment selection. CONCLUSION: This study provided the detailed evidences that applying the on-the-job drilling schema has a significant effect on the skills improvement in diagnostic radiology of rural physicians. It was also concluded that the educational intervention based on practical cases was better than that only based on didactic slides presentation.