This study investigated a novel coronary knobby scoring balloon through finite element analysis (FEA) and in vitro anti-slippage testing, evaluating its dilation process under various vascular conditions and comparing it with other balloons. The FEA results indicated that in the cases of healthy artery and diseased artery with different stenosis rates, the stress on the vessels caused by the knobby scoring balloon was significantly smaller than that of the scoring balloon, and was close to that of the plain balloon. In vitro anti-slippage testing showed that the slippage distance of a plain balloon was 0.11±0.06 mm, and there was no slippage for knobby scoring balloon under nominal pressure. Knobby scoring balloon can effectively expand calcified lesion while providing anti-slippage function, and has a lower risk of vascular injury.
Finite Element Analysis ; Humans ; Angioplasty, Balloon, Coronary/instrumentation* ; Equipment Design ; Biomechanical Phenomena ; Coronary Vessels

BACKGROUND:Surface electromyography has been extensively utilized for monitoring muscle fatigue. However,traditional electromyographic metrics typically focus on individual muscles and fail to assess the variations in a muscle group during the fatigue process. OBJECTIVE:To establish a muscle functional network to extract complex network parameters and investigate the topological property changes of the muscle functional network under different levels of fatigue,aiming to provide theoretical and methodological foundations for fatigue monitoring and prevention. METHODS:Eleven participants performed single-leg leg press exercise at 50％ of one-repetition maximum until exhaustion. Simultaneously,electromyographic signals of seven muscles (rectus femoris,vastus lateralis,vastus medialis,biceps femoris,tibialis anterior,lateral gastrocnemius,and medial gastrocnemius),electrocardiographic signals,and Borg CR-10 scale scores were collected. The Borg CR-10 scale was used to categorize three fatigue stages:mild,moderate,and severe. Heart rate and heart rate variability were calculated to validate the effective division of fatigue stages. Using the coherence of muscle signals,a muscle functional network was constructed with the seven muscles as nodes,and four complex network parameters (clustering coefficient,average weighted degree,global efficiency,and eigenvector centrality) were extracted. Additionally,four electromyographic indices (root mean square,median frequency,instantaneous mean frequency,and co-activation ratio) were extracted and compared under the three levels of fatigue. RESULTS AND CONCLUSION:(1) Differences in heart rate and heart rate variability were observed across three fatigue stages,indicating the effectiveness of fatigue stage delineation. (2) Electromyographic indicators for different muscles under three levels of fatigue:root mean square and co-activation ratio showed no differences;however,median frequency exhibited robust fatigue trends in vastus lateralis,vastus medialis,and biceps femoris,while instantaneous mean frequency demonstrated robust fatigue trends in rectus femoris,vastus lateralis,vastus medialis,and biceps femoris. Instantaneous mean frequency outperformed median frequency and root mean square,yet all three indicators showed robust trends only for the major working muscle groups,unaffected by fatigue factors,unlike the co-activation ratio. (3) The connectivity strength between vastus lateralis and vastus medialis,vastus lateralis and biceps femoris,vastus lateralis and gastrocnemius medialis,and vastus medialis and biceps femoris gradually increased,showing significant differences in average weighted degree,clustering coefficient,and global efficiency post-fatigue,significantly correlated with fatigue levels. To conclude,changes in connectivity strength reflect the synergy and complementarity among muscles during fatigue. Clustering coefficient,average weighted degree,and global efficiency serve as fatigue markers reflecting overall muscle changes.

OBJECTIVE:To explore the efficacy of different exercise regimens to reduce fall risks in older adults.METHODS:PubMed,Embase,Web of Science,The Cochrane Library,WanFang,and CNKI were searched for studies about exercise interventions on fall risk in healthy older adult individuals at the age of 60 years and above.The search timeframe should cover from the inception of each database to July 2023.Quality assessment and risk-of-bias were assessed using the Cochrane risk of bias tool.Meta-analysis,subgroup analysis,sensitivity analysis,and publication bias were conducted using Review Manager 5.3 and Stata 16.0.RESULTS:A total of 45 papers containing 54 studies with 3 074 participants were included in the analysis.Overall,exercise intervention can improve the interventional effects on balance(the unipedal stance test with eyes open,functional reach,Timed"Up & Go",and Berg balance scale),lower limb muscle strength(30-second chair-stand test,Five-Times Sit-To-Stand Test,and Short Physical Performance Battery),and fall-efficacy(Falls Efficacy Scale-International),leading to reduced fall risk(P＜0.05).The Meta-analysis results revealed a dosage effect of different exercise regimens to reduce fall risk in the elderly.Mind-body exercise could efficiently increase scores of the unipedal stance test[mean difference(MD)=6.81,95％confidence interval(CI)(2.17,11.44),P＜0.01];resistance exercise could efficiently increase the scores of the Timed"Up & Go"[MD=-3.12,95％CI(-5.72,-0.52),P＜0.05]and the 30-second chair-stand test[MD=1.22,95％CI(0.37,2.08),P＜0.01];and multicomponent physical activity could efficiently increase the scores of functional reach[MD=4.50,95％CI(2.58,6.42),P＜0.01],Berg Balance Scale[MD=1.05,95％CI(0.39,1.71),P＜0.01],Five-Times Sit-To-stand Test[MD=-3.15,95％CI(-4.80,-1.50),P＜0.01],Short Physical Performance Battery[MD=0.55,95％CI(0.37,0.74),P＜0.01],and Falls Efficacy Scale-International[MD=-0.41,95％CI(0.69,-0.13),P＜0.01].Conclusion:Exercise interventions can effectively improve balance,enhance limb strength and functional ability,and reduce fear of falling,and lower the risk of falls in older adults.The components of different intervention programs(such as type of exercise,duration,frequency,and session length)have varying dose-response relationships with the results of fall risk screening tests in older adults.

Objective To develop a three-compartment kinetic fatigue model for the isometric muscle endurance of the hip,knee,and ankle joints at 50％IPT(isometric peak torque),so as to provide a theoretical basis for simulation-based assessments and load evaluations in biomechanics and sports science.Methods The IPT of the hip,knee,and ankle joints was measured in 40 male university students.Isometric endurance tests were then performed on all three joints at 50％IPT until exhaustion.Electromyography data and endurance time(ET)of major lower limb muscles were collected concurrently.The differences between ETs predicted by models based on previously recommended F and R parameters and actual ETs were analyzed.Subsequently,experimental ETs were used in a grid search to optimize Fand R parameters,allowing for the development of an accurate three-compartment kinetic model.Results The ET of the hip and ankle joints was significantly longer than that of the knee joint(P＜0.001).Models using previously recommended Fand R parameters overestimated ET,with significantly higher predicted values than experimentally measured ET(P＜0.001),as well as elevated root mean squared error(RMSE)and mean relatvie error(MRE)values.The grid search successfully identified Fand R parameters for the three-compartment model in isometric endurance tests of lower limb joints,with no statistical difference between model-predicted ET and experimental ET(P＞0.05).Conclusions The developed model in this study can serve as an indirect measurement tool for evaluating load in similar activities.

Objective:To propose a functional method for locating the shoulder joint center of rotation aimed at rapid estimation of the upper limb reachable domain envelope, thereby informing ergonomic design and task optimization.Methods:In March 2024, shoulder kinematics during gait were recorded from ten adults using a three-dimensional motion-capture system. Assuming the existence of a point near the glenohumeral joint that maintains a fixed spatial relationship to the humerus and the acromion, we estimated both static and dynamic centers of rotation. Localization accuracy was quantified by the standard deviation of distance residuals to upper-arm markers. Upper-limb joint angles and anthropometric parameters were modeled via regression; combined with maximal joint ranges of motion, these were used to infer the reachable domain envelope.Results:The static center of rotation was located approximately twenty-two millimeters medial to the acromial landmark in the coronal plane and thirty-seven millimeters inferior to it. The standard deviation of the residuals for the distances from the dynamic shoulder joint center of rotation to upper-arm markers averaged 1.02 mm, which was 47.42% lower than that of the static center of rotation and 66.56% lower than that of the acromion. Moreover, the trajectory of this dynamic center showed a strong correlation with upper-limb joint angles ( R2>0.7) . Conclusion:The proposed method enables rapid and accurate estimation of the upper limb reachable domain envelope to support ergonomic design and may help reduce the risk of work-related musculoskeletal disorders.

Objective:To explore the common risk factors of sarcopenia in middle-aged and elderly inpatients with type 2 diabetes mellitus(T2DM).Methods:A total of 1 125 middle-aged and elderly T2DM inpatients admitted to the Endocrinology Department of Beijing Hospital from January 2014 to December 2019 were selected and divided into three groups according to age: 50-<60 years old, 60-<75 years old, and ≥75 years old; According to the inclusion and exclusion criteria, 269 study subjects were divided into sarcopenia group( n=90)and non-sarcopenia group( n=179). General data of 1 125 subjects were collected and analyzed.With the presence or absence of sarcopenia as the dependent variable, multivariate logistic regression was used to analyze the relevant risk factors of sarcopenia in middle-aged and elderly inpatients with T2DM.With the comparison of the differences between the sarcopenia group and the non-sarcopenia group, stepwise regression analysis was used to explore the related factors of sarcopenia occurrence. Results:Among the 1 125 patients, the detection rate of muscle content reduction in male was 18.26%, which was significantly higher than that in female 9.28%( P<0.05). The detection rate of muscle content reduction in the senile group was higher than that in 50-<60 years old group and 60-<75 years old group( P<0.05). The proportion of patients with sarcopenia in ≥75 years old group was higher than that in 50-<60 years old group and 60-<75 years old group( P<0.05). The prevalence of sarcopenia in male and ≥75 years old groups was significantly higher than that in female in 50-<60 years old group and the senile group( P<0.05). Logistic regression analysis showed that T2DM patients aged ≥75( OR=4.992, 95% CI: 2.448-10.179)and with glycated hemoglobin(HbA1c)>10%( OR=3.563, 95% CI: 1.526-8.322)had a significantly increased risk of sarcopenia( P<0.05). The proportion of patients with ≥75 years, with a diatetes duration of ≥20 years, with hypertension, with coronary heart disease, with asthma, treated with dipeptidyl peptidase-4(DPP-4)inhibitors, with low albumin and with HbA1c<7% in the sarcopenia group was higher than that in the non-sarcopenia group( P<0.05). T2DM patients aged ≥75 years old( OR=12.140, 95% CI: 2.740-53.790), with a diabetes duration of ≥20 years( OR=3.270, 95% CI: 1.100-9.740), with asthma( OR=7.570, 95% CI: 1.270-45.150), no use of DPP-4 inhibitors( OR=1.950, 95% CI: 1.070-3.570), and with a 2-hour postpranpranal blood glucose ≥11.1mmol/L( OR=0.160, 95% CI: 0.060-0.420)had a significantly increased risk of sarcopenia.( P<0.05). Conclusions:Male and elderly inpatients with T2DM aged ≥ 75 years have a higher detection rate of muscle content reduction and sarcopenia.The main risk factors for sarcopenia in middle-aged and elderly inpatients with T2DM include age HbA 1C, diabetes duration, asthma, use of DPP-4 inhibitors and 2-hour postprandial blood glucose.

Objective:To explore the common risk factors of sarcopenia in middle-aged and elderly inpatients with type 2 diabetes mellitus(T2DM).Methods:A total of 1 125 middle-aged and elderly T2DM inpatients admitted to the Endocrinology Department of Beijing Hospital from January 2014 to December 2019 were selected and divided into three groups according to age: 50-<60 years old, 60-<75 years old, and ≥75 years old; According to the inclusion and exclusion criteria, 269 study subjects were divided into sarcopenia group( n=90)and non-sarcopenia group( n=179). General data of 1 125 subjects were collected and analyzed.With the presence or absence of sarcopenia as the dependent variable, multivariate logistic regression was used to analyze the relevant risk factors of sarcopenia in middle-aged and elderly inpatients with T2DM.With the comparison of the differences between the sarcopenia group and the non-sarcopenia group, stepwise regression analysis was used to explore the related factors of sarcopenia occurrence. Results:Among the 1 125 patients, the detection rate of muscle content reduction in male was 18.26%, which was significantly higher than that in female 9.28%( P<0.05). The detection rate of muscle content reduction in the senile group was higher than that in 50-<60 years old group and 60-<75 years old group( P<0.05). The proportion of patients with sarcopenia in ≥75 years old group was higher than that in 50-<60 years old group and 60-<75 years old group( P<0.05). The prevalence of sarcopenia in male and ≥75 years old groups was significantly higher than that in female in 50-<60 years old group and the senile group( P<0.05). Logistic regression analysis showed that T2DM patients aged ≥75( OR=4.992, 95% CI: 2.448-10.179)and with glycated hemoglobin(HbA1c)>10%( OR=3.563, 95% CI: 1.526-8.322)had a significantly increased risk of sarcopenia( P<0.05). The proportion of patients with ≥75 years, with a diatetes duration of ≥20 years, with hypertension, with coronary heart disease, with asthma, treated with dipeptidyl peptidase-4(DPP-4)inhibitors, with low albumin and with HbA1c<7% in the sarcopenia group was higher than that in the non-sarcopenia group( P<0.05). T2DM patients aged ≥75 years old( OR=12.140, 95% CI: 2.740-53.790), with a diabetes duration of ≥20 years( OR=3.270, 95% CI: 1.100-9.740), with asthma( OR=7.570, 95% CI: 1.270-45.150), no use of DPP-4 inhibitors( OR=1.950, 95% CI: 1.070-3.570), and with a 2-hour postpranpranal blood glucose ≥11.1mmol/L( OR=0.160, 95% CI: 0.060-0.420)had a significantly increased risk of sarcopenia.( P<0.05). Conclusions:Male and elderly inpatients with T2DM aged ≥ 75 years have a higher detection rate of muscle content reduction and sarcopenia.The main risk factors for sarcopenia in middle-aged and elderly inpatients with T2DM include age HbA 1C, diabetes duration, asthma, use of DPP-4 inhibitors and 2-hour postprandial blood glucose.

Objective:To propose a functional method for locating the shoulder joint center of rotation aimed at rapid estimation of the upper limb reachable domain envelope, thereby informing ergonomic design and task optimization.Methods:In March 2024, shoulder kinematics during gait were recorded from ten adults using a three-dimensional motion-capture system. Assuming the existence of a point near the glenohumeral joint that maintains a fixed spatial relationship to the humerus and the acromion, we estimated both static and dynamic centers of rotation. Localization accuracy was quantified by the standard deviation of distance residuals to upper-arm markers. Upper-limb joint angles and anthropometric parameters were modeled via regression; combined with maximal joint ranges of motion, these were used to infer the reachable domain envelope.Results:The static center of rotation was located approximately twenty-two millimeters medial to the acromial landmark in the coronal plane and thirty-seven millimeters inferior to it. The standard deviation of the residuals for the distances from the dynamic shoulder joint center of rotation to upper-arm markers averaged 1.02 mm, which was 47.42% lower than that of the static center of rotation and 66.56% lower than that of the acromion. Moreover, the trajectory of this dynamic center showed a strong correlation with upper-limb joint angles ( R2>0.7) . Conclusion:The proposed method enables rapid and accurate estimation of the upper limb reachable domain envelope to support ergonomic design and may help reduce the risk of work-related musculoskeletal disorders.

OBJECTIVE:To explore the efficacy of different exercise regimens to reduce fall risks in older adults.METHODS:PubMed,Embase,Web of Science,The Cochrane Library,WanFang,and CNKI were searched for studies about exercise interventions on fall risk in healthy older adult individuals at the age of 60 years and above.The search timeframe should cover from the inception of each database to July 2023.Quality assessment and risk-of-bias were assessed using the Cochrane risk of bias tool.Meta-analysis,subgroup analysis,sensitivity analysis,and publication bias were conducted using Review Manager 5.3 and Stata 16.0.RESULTS:A total of 45 papers containing 54 studies with 3 074 participants were included in the analysis.Overall,exercise intervention can improve the interventional effects on balance(the unipedal stance test with eyes open,functional reach,Timed"Up & Go",and Berg balance scale),lower limb muscle strength(30-second chair-stand test,Five-Times Sit-To-Stand Test,and Short Physical Performance Battery),and fall-efficacy(Falls Efficacy Scale-International),leading to reduced fall risk(P＜0.05).The Meta-analysis results revealed a dosage effect of different exercise regimens to reduce fall risk in the elderly.Mind-body exercise could efficiently increase scores of the unipedal stance test[mean difference(MD)=6.81,95％confidence interval(CI)(2.17,11.44),P＜0.01];resistance exercise could efficiently increase the scores of the Timed"Up & Go"[MD=-3.12,95％CI(-5.72,-0.52),P＜0.05]and the 30-second chair-stand test[MD=1.22,95％CI(0.37,2.08),P＜0.01];and multicomponent physical activity could efficiently increase the scores of functional reach[MD=4.50,95％CI(2.58,6.42),P＜0.01],Berg Balance Scale[MD=1.05,95％CI(0.39,1.71),P＜0.01],Five-Times Sit-To-stand Test[MD=-3.15,95％CI(-4.80,-1.50),P＜0.01],Short Physical Performance Battery[MD=0.55,95％CI(0.37,0.74),P＜0.01],and Falls Efficacy Scale-International[MD=-0.41,95％CI(0.69,-0.13),P＜0.01].Conclusion:Exercise interventions can effectively improve balance,enhance limb strength and functional ability,and reduce fear of falling,and lower the risk of falls in older adults.The components of different intervention programs(such as type of exercise,duration,frequency,and session length)have varying dose-response relationships with the results of fall risk screening tests in older adults.

Objective To develop a three-compartment kinetic fatigue model for the isometric muscle endurance of the hip,knee,and ankle joints at 50％IPT(isometric peak torque),so as to provide a theoretical basis for simulation-based assessments and load evaluations in biomechanics and sports science.Methods The IPT of the hip,knee,and ankle joints was measured in 40 male university students.Isometric endurance tests were then performed on all three joints at 50％IPT until exhaustion.Electromyography data and endurance time(ET)of major lower limb muscles were collected concurrently.The differences between ETs predicted by models based on previously recommended F and R parameters and actual ETs were analyzed.Subsequently,experimental ETs were used in a grid search to optimize Fand R parameters,allowing for the development of an accurate three-compartment kinetic model.Results The ET of the hip and ankle joints was significantly longer than that of the knee joint(P＜0.001).Models using previously recommended Fand R parameters overestimated ET,with significantly higher predicted values than experimentally measured ET(P＜0.001),as well as elevated root mean squared error(RMSE)and mean relatvie error(MRE)values.The grid search successfully identified Fand R parameters for the three-compartment model in isometric endurance tests of lower limb joints,with no statistical difference between model-predicted ET and experimental ET(P＞0.05).Conclusions The developed model in this study can serve as an indirect measurement tool for evaluating load in similar activities.