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Background Climbing pylons during high-voltage cable maintenance is not only a labor-intensive task, but also a challenge bringing about heat stress and mental pressure from working at height, which may lead to accumulation of muscle fatigue and work-related musculoskeletal disorders. Objective To record the local muscle fatigue during a simulated climbing task by high-voltage cable electricians based on surface electromyography (sEMG) signals, explore the characteristic changes in sEMG signals and their relationship with subjective fatigue evaluation of the task, and provide data support for developing task specific objective assessment tools for local muscle fatigue and prevention of work-related musculoskeletal disorders. Methods Ten male college students were recruited to conduct a test of a simulated pylon climbing task. The climbing distance was 60 m, and a task segment was set for every 20 m (about 100 s), recorded as T1, T2, and T3, respectively. After completing each task segment, the subjects were required to rate their subjective fatigue using the Borg's RPE Scale. Fatigue was defined by rating of perceived exertion (RPE) score ≥ 14 in this study. The sEMG signals of trapezius, erector spinae, rectus femoris, and gastrocnemius muscles were recorded wirelessly. The standardized maximal voluntary electrical activation (MVE) obtained by standardizing the root mean square (RMS) of the time domain index and the median frequency (MF) of the frequency domain index were estimated for the recorded sEMG signals, and joint amplitude and spectrum analysis (JASA) was used to evaluate local muscle fatigue of target muscles involving in the climbing task. Results The RPE scores of T1, T2, and T3 were 11.9, 15.3, and 17.4, respectively. Subjective fatigue was found in T2 and T3 but not in T1. With the extension of climbing time, the MVE values of left and right erector spinae muscles, left and right rectus femoris, and right gastrocnemius muscle increased gradually, while the MVE values of left and right trapezius muscles and left gastrocnemius muscle increased first and then decreased. The MF values of left and right rectus femoris increased at first, then remained unchanged, while the MF values of the other muscles remained basically unchanged. In T1, three muscles, including left trapezius muscle and both side of erector spinae muscles, showed fatigue; in T2, five muscles, including both sides of erector spina muscles, right trapezius muscle, and both sides of gastrocnemius muscle appeared fatigue; in T3 , except for left rectus femoris, the other seven muscles were fatigue. Conclusion The characteristic changes of electromyography signals in the simulated climbing task are not completely consistent with the typical amplitude increase and left shift of the frequency spectrum of sEMG signals in static tasks, indicating that the application of time-domain and frequency-domain analysis methods in the evaluation of muscle fatigue in climbing tasks needs further discussion. Trapezius muscles and erector spinae muscles are the first to show fatigue in the simulation, and may be the sensitive muscle groups of muscle fatigue associated with climbing movement. Compared with subjective evaluation, surface electromyography is more sensitive in the assessment of body fatigue. Fatigue is reported about 100 s of climbing (the climbing length is about 20 m).
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Background Long working hours is harmful to the physical and mental health of occupational groups, and should receive active attention. Objective To evaluate the current status of long working hours among operation and maintenance workers of power supply enterprises, and explore its effects on work-related musculoskeletal disorders (WMSDs) of the population. Methods From March to June 2021, a cross-sectional survey was conducted among 1433 operation and maintenance workers from 10 power supply enterprises in Jilin Province, Shandong Province, and Tianjin Municipality using cluster sampling. A total of 1433 copies of revised Mus-culoskeletal Disorders Questionnaire were distributed, 1343 questionnaires were recovered, and the recovery rate was 93.72%. The questionnaire included general information, personal health behaviors, weekly working hours, work-related factors, and musculoskeletal pain or discomfort in nine body parts in the past 12 months. χ2 test and multiple logistic regression models were used to investigate the relationships between long working hours (>40 h per week) and WMSDs. Results The average age of the workers was (39.42±9.89) years, and the average work experience was 11.00 (5.00, 21.00) years. There were 1158 males (86.22%) and 185 females (13.78%). The average weekly working hours of the workers were (47.98±11.35) h, and the proportion of long working hours (>40 h per week) was 61.06% (820/1343). The proportions of long working hours were higher among the workers with characteristics of male, power distribution, shift work, often/very often long-time standing, often/very often holding awkward postures, often handling heavy objects, limited space to operate, long-time neck tilting backward, keeping arms above shoulders, frequent elbow bending, repeating knee movement every minute, and repeating lower limb or foot movement every minute (all P<0.05). The prevalence rate of WMSDs was 81.53% (1095/1343) among the workers. The results of multiple logistic regression showed that after adjusting education, smoking, exercise, awkward postures, often handling heavy objects, limited space to operate, long-time heavy trunk bending, long-time neck tilting backward, and keeping arms above shoulders, compared with working ≤40 h per week, the risk of WMSDs among workers working >49 h per week was higher (OR=1.406, 95%CI: 1.011-1.955). Conclusion Long working hours is prominent among operation and maintenance workers of power supply enterprises, and increases the risk of reporting WMSDs.
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Background Power grid is a basic industry of national economy. The occupational health problems among operation and maintenance workers in this industry have become increasingly prominent in recent years, and they should receive enough attention. Objective To estimate the prevalence of work-related musculoskeletal disorders (WMSDs) of neck and shoulder among operation and maintenance workers of power supply enterprises, and analyze related influencing factors. Methods From March to June 2021, a total of 1433 operation and maintenance worker from 10 power supply enterprises in three provinces of North China were selected as research subjects using cluster sampling method. A revised Musculoskeletal Disorders Questionnaire was used to investigate the prevalence and ergonomic factors of neck and shoulder pain in the past year. χ2 test and logistic regression model were used to explore influencing factors of neck and shoulder pain among operation and maintenance workers. Results A total of 1343 valid questionnaires were recovered and the effective recovery rate was 93.72%. The neck pain prevalence was 66.0% (886 cases) and the shoulder pain prevalence was 54.1% (727 cases). The multiple logistic regression analysis results showed that often/very often long-time sitting (OR=1.864, 95%CI: 1.236-2.811; OR=1.659, 95%CI: 1.091-2.524), sometimes holding awkward postures (OR=1.695, 95%CI: 1.294-2.219; OR=1.596, 95%CI: 1.218-2.092), often/very often holding awkward postures (OR=2.416, 95%CI: 1.618-3.607; OR=2.058, 95%CI: 1.405-3.015), long-time slight neck tilting forward (OR=1.327, 95%CI: 1.023-1.722; OR=1.571, 95%CI: 1.221-2.022), long-time elbows bending (OR=1.327, 95%CI: 1.023-1.722; OR=1.506, 95%CI: 1.112-2.040) and department or team staff shortages (OR=1.578, 95%CI: 1.153-2.161; OR=1.831, 95%CI: 1.320-2.539) were associated with higher neck and shoulder pain prevalence rates. While exercise (OR=0.630, 95%CI: 0.492-0.809; OR=0.707, 95%CI: 0.557-0.899) was associated with lower neck and shoulder pain prevalence rates. Doing same work every day (OR=1.704, 95%CI: 1.305-2.225) was associated with a higher neck pain prevalence rate. Awkward postures with ineffectual force (OR=1.808, 95%CI: 1.226-2.665) and often keeping arms above shoulders (OR=1.424, 95%CI: 1.017-1.992) were associated with a higher shoulder pain prevalence rate. Conclusion The prevalence rates of neck and shoulder pian are high among operation and maintenance workers of power supply enterprises in selected three provinces of North China, and the main associated factors include individual factors, awkward work postures, and labor organization.
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Background Operation and maintenance work in the power grid industry often involving climbing, manual handling, and poor postures causing serious problems like work-related musculoskeletal disorders (WMSDs). The influencing factors of WMSDs are not very clear, but the problem has been widely concerned in this industry. Objective To understand the prevalence and influencing factors of WMSDs among climbing task-involved workers in power supply enterprises. Methods Using a cross-sectional design, a total of 702 workers involving climbing task from 10 power supply enterprises in Jilin Province, Tianjin Municipality, and Shandong province were selected as study subjects using cluster sampling. The Musculoskeletal Disorders Questionnaire which was revised by Lei Yang was used to estimate the prevalence and identify related factors of WMSDs. \begin{document}$ {\chi
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Objective To investigate the procedure and efficacy of medial patellofemoral ligament (MPFL) reconstruction assisted with arthroscopy for recurrent patellar dislocation in adolescents.Methods From March 2012 to March 2017,15 adolescents suffered with recurrent patellar dislocation,who underwent MPFL reconstruction operation,were all adopted with autograft semitendinosus.The patellar side used the modified bone tunnels and the minimally invasive percutaneous grafts through bone tunnels,and then fixed in the femoral tunnel with absorbable interference screw.Follow-up included complications,subjective feeling,patellar apprehension test,recurrent dislocation.Knee function was evaluated by the Kujala score and Lysholm score.Results 15 patients were followed up for at least 12 months.All patients were satisfied with the treatment.No recurrent dislocation occurred.All the patients showed negative apprehension test.The Kujala score was improved from 53.2 ±5.27 (preoperative) to 93.0 ±4.13 (postoperative),with significant difference (t =21.84,P ＜ 0.05);the Lysholm score was improved from 54.5 ± 6.24 to 91.2 ±4.72,with significant difference (t =19.37,P ＜ 0.05).Conclusions MPFL reconstruction assisted with arthroscopy is an effective surgical procedure for adolescent patients wih recurrent patellar dislocation,which can improve the knee function with little trauma and complications.
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OBJECTIVE@#To describe and analyze the clinical features of nasal respiratory epithelial adenomatoid hamartom and improve the levels of diagnosis and treatment.@*METHOD@#Fourteen cases of nasal respiratory epithelial adenomatoid hamartom confirmed by pathology were collected and analyzed.@*RESULT@#In 14 cases, primary complaint of Hyposmia(or Anosmia)and nasal obstruction were occured in 13 and 11 cases respectively. Four cases had past history of endoscopic sinus surgery because of the diagnosis of nasal polyps. Polypoid neoplasms could be seen in the bilateral olfactory clefts. Sinus CT showed soft tissue shadows in bilateral nasal cavity and mucous membrane thickening in different sinus. Endoscopic sinus surgery were utilized to eliminate focus in all cases. All cases weren t recurred after 2-20 months' following-up visitings.@*CONCLUSION@#Nasal respiratory epithelial adenomatoid hamartom is so rare that clinical and pathological doctors have limited knowledge of it. It has its own characteristics from the clinical symptoms, signs to sinus CT although they are nonspecific. So we should improve the understanding about it to avoid misdiagnosis or missed diagnosis.
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Humanos , Diagnóstico Diferencial , Endoscopía , Hamartoma , Diagnóstico , Patología , Cirugía General , Cavidad Nasal , Obstrucción Nasal , Pólipos Nasales , Recurrencia Local de Neoplasia , Neoplasias Nasales , Diagnóstico , Patología , Cirugía General , Senos ParanasalesRESUMEN
ObjectiveTo investigate the expression levels of vascular endothelial growth factor (VEGF)in knee synovial membranes and synovial fluids whether it could be a marker for progressive osteoarthritis.MethodsKnee synovial membranes and synovial fluids of patients with osteoarthritis who were underwent total knee arthroplaaty or arthroscopy were collected. They were classified into four groups according to the radiographic grading[Kellegren-Lawrence(K-L) grade]. Appoint K-L-0-grade patients who suffered from menisci injuries only served as controls. The levels of VEGF in the synovial fluid were measured by enzymelinked immunosorbent assay(ELISA) and VEGF-secreting cells were identified by immunohistochemistry.ANOVA was used for statistical analysis. ResultsVarious degrees of inflammation could be found in all the samplesevaluated histologically on HE-stained sections. Synovial tissue inflammation presented as synovial lining thickening, and inflammatory cells infiltration. VEGF expressed in the synovium linings and surrounding blood vessels. The VEGF levels in the synovial fluids were increased accordingly with K-L grades, which reached the peak level in the late stage of osteoarthritis. The levels of VEGF in the synovial fluids were significantly higher in patients with osteoarthritis[from (1181±116), (1632±140) to (2252±216) pg/ml]than in those with menisci injury (P＜0.01); The percent ages positive cell in each groups were (5±4)％ , (9±4)％,(16±6)％ and (21±6)％ respectively, there were significantly differences too (P＜0.01). ConclusionVEGF originated from synovial tissue may play a role in the pathogenesis of osteoarthritis. High levels of VEGF in the synovial fluids can be regarded as the marker of active osteoarthritis.