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.

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 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 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.

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 investigate the application value of enhanced recovery after surgery (ERAS) in perioperative period of laparoscopic sleeve gastrectomy (LSG).Method:The retrospective cohort study was conducted. The clinical data of 1 181 patients undergoing LSG in the Sir Run Run Shaw Hospital, Affiliated with the Zhejiang University School of Medicine from January 2021 to December 2023 were collected. There were 242 males and 939 females, aged (31±8)years. Of 1 181 patients, 598 cases receiving routine perioperative care were divided into the control group, and 583 cases receiving perioperative care with ERAS were divided into the ERAS group. Measurement data with normal distribution were represented as Mean± SD, and the independent sample t test was used for comparison between the groups. Measurement data with skewed distribution were represented as M( Q1, Q3), and the Mann-Whitney rank sum test was used for comparison between the groups. Count data were expressed as absolute numbers or percentages, and the chi-square test or Fisher exact probability were used for comparison between the groups. Repeated measurement data were analyzed using the repeated ANOVA, with baseline scores as covariates. Simple effects analysis was conducted in case of interaction, and multiple comparisons were adjusted using the Bonferroni method. Results:(1) Postoperative outcomes. The numerical rating scale (NRS) scores for pain at immediate return to the ward and on the third postoperative mornings changed from 5.35±0.93 to 2.57±0.83 in the control group, versus changed from 3.15±0.93 to 0.70±0.65 in the ERAS group, showing significant difference between the two groups ( Ftime=66.58, Fgroup=1 765.85, Finteraction=6.90, P<0.05). After adjusting NRS scores for pain at immediate return to the ward as the baseline, results of simple effects analysis showed that on the third postoperative mornings, the NRS scores in the ERAS group were lower by 1.89, 1.53, and 1.76 respectively compared to the control group ( P<0.05). Cases with nausea at immediate return to the ward and on the third postoperative mornings changed from 497 to 97 in the control group, versus changed from 198 to 11 in the ERAS group, showing signifi-cant difference between the two groups ( χ2=294.45, 398.76,209.39, 73.00, P<0.05). Cases with vomiting at immediate return to the ward and on the third postoperative mornings changed from 243 to 41 in the control group, versus changed from 51 to 2 in the ERAS group, showing significant difference between the two groups ( χ2=160.54, 149.37, 71.76, 35.69, P<0.05). The duration of postoperative hospital stay was (3.22±0.65)days in the control group, versus (2.17±0.49)days in the ERAS group, showing a significant difference between the two groups ( t=-11.89, P<0.05). (2) Complications. The incidence of cases with dehydration within postoperative 30 days was 0.50%(3/598) in the control group, versus 0.69%(4/583) in the ERAS group, showing no significant difference between the two groups ( P>0.05). None of patient in the control group and the ERAS group experienced bleeding, gastric leakage, intra-abdominal infection, and no patient had unplanned secondary surgery within postoperative 30 days. Conclusions:ERAS in perioperative period of LSG are safe and feasible. Compared to routine care, ERAS can significantly reduce postoperative pain, decrease the incidence of postoperative nausea and vomiting, shorten the postoperative hospital stay, and do not increase the rate of postoperative complications or unplanned secondary surgeries within postoperative 30 days.

Objective:To explore the effect of ointment massage on the postoperative recovery of newborns who had intestinal tract operation, aim to construct an effective post-operative ointment and massage scheme and to enrich the content of enhanced recovery after surgery in the field of newborns.Methods:Delphi expert inquiry method was used to construct the ointment message scheme. A total of 64 newborns undergone intestinal surgery from May 2022 to May 2023 in Guangdong Women and Children Hospital were selected as study subjects and divided into routine group (34 cases) and ointment group (30 cases) by random number table method. In addition to routine treatment and nursing, the newborns in the ointment group also received ointment massage. The postoperative gastrointestinal drainage volume, fasting days, the first feeding time, hospital stay and the number of cases of vomiting and abdominal distension between the two groups were compared.Results:A total of 16 experts with (38.93 ± 5.13) years old were inquired, 6 males and 10 females. The effective questionnaire response rates for the two rounds of expert inquiry were 16/16 and 15/16, the expert authority coefficients were both≥0.80, the Kendall′s W coefficients were 0.117 and 0.107, with statistically significant differences (both P<0.05). A ointment message scheme consisting of 8 acupoints and 7 kinds of traditional Chinese medicines was determined. In the routine group, there were 19 males and 15 females with (268.47 ± 11.27) gestational age. In the ointment group, there were 20 males and 10 femles with (271.93 ± 10.36) gestational age. The postoperative gastrointestinal drainage volume, fasting days, the first feeding time and the hospital stay in the ointment group were 74.0 ml, 6.0 d, 158.5 h and 13.0 d, which had significant differences with the 184.5 ml, 7.5 d, 192.0 h, 16.5 d in the routine group ( Z values were 2.07-2.45, all P<0.05). The incidence of vomiting and abdominal distension in the ointment group were both 8 cases, which were lower than the 19 and 18 cases in the routine group with a statistically significant difference ( χ2 = 5.58, 4.56, both P<0.05). Conclusions:The ointment massage in this study has a positive impact on the recovery of newborn infants after intestinal surgery, with high safety, in line with enhanced recovery after surgery concept, and is worthy of promotion.

Objective:To learn about the clinical manifestations, laboratory characteristics and treatment of patients with acute and chronic brucellosis.Methods:Clinical data of 153 brucellosis patients admitted to the Guangzhou Eighth People's Hospital, Guangzhou Medical University from 2012 to 2022 were retrospectively collected, including general information, epidemiological characteristics, clinical manifestations, laboratory test results, imaging examination results, treatment and prognosis. According to the course of disease < 180 d and ≥180 d, these patients were divided into acute brucellosis group and chronic brucellosis group, and the clinical data of the two groups of patients were compared and analyzed.Results:A total of 153 patients with brucellosis were included, including 119 in the acute brucellosis group and 34 in the chronic brucellosis group. The age was (46.2 ± 13.8) years old, with 115 males (75.2%) and 38 females (24.8%), and 85 patients (55.6%) were occupational exposed. Complications occurred in 90 patients (58.8%), and the incidence of complications in the acute brucellosis group was lower than that in the chronic brucellosis group [76.5% (26/34) vs 53.8% (64/119), χ 2 = 5.62, P = 0.018]. The most common clinical manifestations were fever and arthralgia, with 128 cases (83.7%) and 124 cases (81.0%), respectively. The incidence of fever in the acute brucellosis group was higher than that in the chronic brucellosis group [87.4% (104/119) vs 70.6% (24/34), χ 2 = 5.46, P = 0.019], while the incidence of arthralgia was lower than that in the chronic brucellosis group [77.3% (92/119) vs 94.1% (32/34), χ 2 = 4.83, P = 0.027]. In laboratory tests, the positive rate of blood culture was 59.5% (91/153), and it was higher in the acute brucellosis group than that in the chronic brucellosis group [67.2% (80/119) vs 32.4% (11/34), P < 0.05]. The incidence of elevated procalcitonin [PCT, 58.6% (58/99) vs 24.1% (7/29), χ 2 = 10.65, P = 0.001] and the incidence of liver dysfunction [33.9% (40/118) vs 15.2% (5/33), χ 2 = 4.33, P = 0.037] in the acute brucellosis group were higher than those in the chronic brucellosis group. In the imaging examination, 61 patients (39.9%) experienced bone destruction, and the incidence of bone destruction in the chronic brucellosis group was higher than that in the acute brucellosis group [55.9% (19/34) vs 35.3% (42/119), χ 2 = 4.68, P = 0.031]. All patients were treated with antibiotics, with a median of 3 and 4 types of antibiotics used in the acute and chronic brucellosis groups, respectively. The overall incidence of adverse drug reactions was 5.2% (8/153). After treatment, 65 cases (42.5%) recovered, 70 cases (45.8%) improved, and 18 cases (11.8%) did not recover. Conclusions:The main clinical manifestations of brucellosis patients are fever and arthralgia, with a high incidence of complications. All patients are treated with combined antibiotics therapy. Patients in acute brucellosis group have a higher incidence of fever, positive blood culture, elevated PCT and abnormal liver function, while patients in chronic brucellosis group have a higher incidence of complications, arthralgia and bone destruction.