Objective:To explore the structural relationship between WMSDs in the upper limbs and various risk factors in the occupational population in China, based on a large sample epidemiological survey and structural equation analysis, and to establish a structural equation model, so as to lay a foundation for the prevention and control of such diseases.Methods:The Chinese version of the Musculoskeletal Disorders Electronic Questionnaire was used to conduct a nationwide survey on the prevalence of WMSDs in the upper extremity. Six factors related to WMSDs in the upper extremity were extracted by the classification standard of adverse ergonomic factors and their source and confirmatory factor analysis, including work organization, work type, upper extremity work posture, individual factors, upper extremity fatigue and upper extremity WMSDs. The structural equation analysis was carried out and the structural equation model was established.Results:The incidence of WMSDs and fatigue in the upper limbs was 24.44% and 43.76%, respectively. The adjusted structural equation model fitting indicators were generally up to the standard (GFI=1.000, AGFI=1.000, RMSEA=0.043, NFI=0.808, TLI=0.784) . The four exogenous latent variables of work organization, work type, upper limb work posture and individual factors were correlated. There was a strong positive correlation between job type and upper limb work posture ( r=0.865) , a moderate positive correlation between work organization and job type and upper limb work posture ( r=0.570, 0.490) , and a weak negative correlation between individual factors and the other three exogenous latent variables. Upper limb work posture and individual factors had direct effects on upper limb WMSDs, and the effect coefficients were 0.10 and 0.06, respectively. Upper limb fatigue played a mediating role between work organization, work type, upper limb work posture and upper limb WMSDs. The effect coefficient was 0.46, and the composition ratios of indirect effects were 100.0%, 100.0%, and 38.3%, respectively. The direct path effect of upper limb work posture, individual factors and upper limb WMSDs was weaker than the mediating path through upper limb fatigue. Conclusion:When carrying out the prevention and control of upper limbWMSDs, it is necessary to comprehensively consider the pathogenesis path of upper limb muscle fatigue and upper limb WMSDs caused by work organization, work type, and upper limb work posture, so as to provide theoretical reference for improving the prevention and control level of such diseases.

Objective:To explore the structural relationship between WMSDs in the upper limbs and various risk factors in the occupational population in China, based on a large sample epidemiological survey and structural equation analysis, and to establish a structural equation model, so as to lay a foundation for the prevention and control of such diseases.Methods:The Chinese version of the Musculoskeletal Disorders Electronic Questionnaire was used to conduct a nationwide survey on the prevalence of WMSDs in the upper extremity. Six factors related to WMSDs in the upper extremity were extracted by the classification standard of adverse ergonomic factors and their source and confirmatory factor analysis, including work organization, work type, upper extremity work posture, individual factors, upper extremity fatigue and upper extremity WMSDs. The structural equation analysis was carried out and the structural equation model was established.Results:The incidence of WMSDs and fatigue in the upper limbs was 24.44% and 43.76%, respectively. The adjusted structural equation model fitting indicators were generally up to the standard (GFI=1.000, AGFI=1.000, RMSEA=0.043, NFI=0.808, TLI=0.784) . The four exogenous latent variables of work organization, work type, upper limb work posture and individual factors were correlated. There was a strong positive correlation between job type and upper limb work posture ( r=0.865) , a moderate positive correlation between work organization and job type and upper limb work posture ( r=0.570, 0.490) , and a weak negative correlation between individual factors and the other three exogenous latent variables. Upper limb work posture and individual factors had direct effects on upper limb WMSDs, and the effect coefficients were 0.10 and 0.06, respectively. Upper limb fatigue played a mediating role between work organization, work type, upper limb work posture and upper limb WMSDs. The effect coefficient was 0.46, and the composition ratios of indirect effects were 100.0%, 100.0%, and 38.3%, respectively. The direct path effect of upper limb work posture, individual factors and upper limb WMSDs was weaker than the mediating path through upper limb fatigue. Conclusion:When carrying out the prevention and control of upper limbWMSDs, it is necessary to comprehensively consider the pathogenesis path of upper limb muscle fatigue and upper limb WMSDs caused by work organization, work type, and upper limb work posture, so as to provide theoretical reference for improving the prevention and control level of such diseases.

OBJECTIVE To investigate the current status of quality management of cold chain medicines in direct-to-patient(DTP)pharmacies and propose measures for pre-emptive risk management,providing references for the quality risk management of cold chain medicines.METHODS Based on the requirements of national regulations,a survey was conducted on the quality management of cold chain medicines in DTP pharmacies of J Province from November 2023 to February 2024,focusing on the receipt,storage,distribution,and delivery processes,using questionnaires,telephone interviews,and on-site visits.Common quality management issues in the operation of cold chain medicines were identified,and the causes of these issues were analyzed to propose feasible pre-emptive risk management measures.RESULTS&CONCLUSIONS A total of 122 DTP pharmacies participated in the questionnaire survey,and personnel from 30 DTP pharmacies participated in on-site and telephone interviews.Typical problems were identified in some DTP pharmacies,including insufficient personnel allocation or training,incomplete or inadequate implementation of quality system documentation,inadequate provision or management of cold chain facilities and equipment,and non-compliant storage and distribution of cold chain medicines.These issues posed certain risks to the quality management of cold chain medicines.It is recommended that DTP pharmacies strengthen personnel allocation and training,improve quality system documentation,enhance the provision and management of facilities and equipment,standardize storage and transportation operations,and strengthen supervision and assessment as pre-emptive measures.In addition,all sectors of society should also collaborate in governance from the perspective of ensuring the safety of cold chain drug storage and transportation,in order to mitigate the risk of quality and safety issues during the distribution of cold chain drugs and guarantee the safe and effective use of medications for patients.

{L-End}Objective To analyze the local muscle response under continuous ergonomic workload by simulating manual lifting, and to screen the sensitive metabolic biomarkers during fatigue process. {L-End}Methods A total of 13 healthy male volunteers were selected as the study subjects using simple random sampling method. Study subjects underwent repetitive simulated manual lifting for four periods (T1 to T4), each lasting 12 minutes. The degree of work-related fatigue in the forearm, upper arm, shoulder, back, and leg muscles, and the whole body was accessed using Borg 6-20 Rating of Perceived Exertion (RPE) Scale. The venous blood samples were collected from elbow between each two periods to detect the levels of eight metabolic biomarkers: ammonia, lactate, creatine kinase, lactate dehydrogenase (LDH), C-terminal telopeptide of type Ⅰ collagen (CTX-Ⅰ), C-terminal telopeptide of type Ⅱ collagen (CTX-Ⅱ), cartilage oligomeric matrix protein (COMP), and calcium ions. {L-End}Results The RPE scores of the study subjects for the muscles of five body parts and the whole body increased with the increasing lifting periods (all P<0.01). Fatigue was observed in all target muscles, with overall body fatigue occurring in the T2 period. The levels of ammonia, lactate, creatine kinase, LDH, COMP, and calcium ions in the serum of study subjects were higher in the T1 to T4 periods than in the T0 period (all P<0.05). The serum CTX-Ⅰ level was higher in the T1 and T3 periods than that in the T0 period (all P<0.05) , and the serum CTX-Ⅱ level was higher in the T1, T2 and T4 periods than that in the T0 period (all P<0.05). The level of these eight serum metabolic biomarkers fluctuated during the T1 to T4 periods. The serum creatine kinase level increased with the period of lifting (all P<0.05). The serum lactate level was higher in the T3 period than those in the T1 and T2 periods (all P<0.05). The serum LDH and calcium ion levels were higher in the T2 to T4 periods than that in the T1 period (all P<0.05). The serum COMP level was higher in the T2 and T3 periods than that in the T1 period (all P<0.05). Except for CTX-Ⅰ, the levels of other seven metabolic markers in serum were higher in individuals after fatigue than before fatigue (all P<0.05). {L-End}Conclusion Serum metabolic biomarkers such as ammonia, lactate, creatine kinase, calcium ions, LDH, CTX-Ⅱ, and COMP exhibit significant changes before and after fatigue. These metabolic biomarkers could be used as sensitive biomarkers for evaluating muscle fatigue during repetitive works.

Background Furniture manufacturing is one of the typical labor-intensive industries, and workers in this industry face a high risk of work-related musculoskeletal disorders (WMSDs), which seriously affect the physical and mental health of workers. Objective To explore the prevalence and potential risk factors of WMSDs among workers in a large-scale furniture manufacturing factory. Methods A cross-sectional study of 3431 workers in a furniture factory in Guangdong Province was conducted from September to December 2019. Information including reported WMSDs in various body parts in the past year, demographic characteristics, work organization factors, job characteristics, and work postures was collected by an electronic version of Musculoskeletal Disorders Questionnaire. Pearson χ² test and binary logistic regression were used to analyze the risk factors leading to WMSDs. Results The overall prevalence rate of WMSDs was 32.12% (1102/3431). The most common WMSDs symptoms occurred in the neck (16.85%), followed by the feet (15.27%), shoulders (14.81%), and hands (14.25%). The prevalence rates of WMSDs in the neck, shoulders, elbows, hands, legs, and feet were significantly different among different types of work (P<0.05). The results of multiple logistic regression analysis showed that individual factors, work organization factors, job characteristics, and awkward work postures were associated with the frequency of reporting WMSDs in specific parts of workers. Comparatively poor physical health (including moderate, poor, and very poor) was positively correlated with neck, shoulder, hand, and foot WMSDs (OR=1.479-4.077); working with an uncomfortable posture (OR=1.983) and doing the same task almost every day (OR=1.783) were positively correlated with neck pain; doing the same task almost every day (OR=2.408) and neck twisting for a long time (OR=1.830) were positively correlated with shoulder pain; bending wrists up and down frequently (OR=1.948) and bending wrists for a long time (OR=2.081) were positively correlated with hand pain; prolonged standing (OR=1.953) and often working overtime (OR=1.627) were positively correlated with feet pain; sufficient rest time was negatively correlated with WMSDs in the neck, shoulders, hands, and foot (OR=0.544-0.717). Conclusion The prevalence rate of WMSDs in furniture manufacturing workers is relatively high, and neck, feet, shoulders, and hands are the most involved body parts. The frequency of reporting WMSDs is related to individual factors, work organization factors, job characteristics, and awkward work postures.

Objective:To investigate the immune effects of Clostridium difficile toxoid B (CdtB) vaccine formulated with different mucosal adjuvants through microneedle immunization, and to provide ideas for the prevention and treatment of Clostridium difficile infection. Methods:CdtB vaccine was prepared with purified Clostridium difficile toxin B(TcdB) after formaldehyde detoxification. Female BALB/c mice were immunized with different doses of vaccine alone or in combination with mucosal adjuvants. The titers of specific serum IgG and fecal IgA were detected at 0 d, 7 d, 14 d, 28 d and 42 d after immunization. The protective effects of CdtB vaccine were evaluated by cell neutralization assay and Clostridium difficile challenge infection. Results:(1) With the increase of immune dose, the mice immunized with CdtB vaccine alone by microneedle not only produced better serum specific IgG, but also had higher level of IgA in feces. (2) When the mice were immunized with CdtB vaccine containing LT or CTB adjuvant by microneedle, the trend of serum specific IgG titer in each group increased with the increase of immune dose, especially in the group containing LT adjuvant. There were significant differences in the trend of specific IgA titer in feces between the adjuvant groups and the group without adjuvant, but the adjuvant effect was not obvious. (3) No significant difference in serum IgG titer was observed between the mice immunized with 10 μg CdtB by microneedle or intraperitoneal injection, but microneedle immunization significantly increased fecal IgA level. (4) The neutralization titers of specific antibodies in mouse serum after immunization and the test results of challenge protection in mice confirmed that the use of CdtB vaccine had certain protective effects.Conclusions:CdtB vaccine had better immune effects in mice through microneedle immunization, but the adjuvant effects of LT and CTB were not significant.

Objective: To analyze the effects of Clostridium difficile toxin B (TcdB) on the proliferation and apoptosis of colon cancer cell line SW480 and the possible mechanisms related to cell apoptosis. Methods: SW480 cells were treated with different concentrations of TcdB. Cell proliferation was detected by MTT assay. Cell apoptosis and mitochondrial membrane potential were measured with flow cytometry. Results: TcdB significantly inhibited the proliferation of SW480 cells in a time-concentration dependent manner and the inhibition rate reached 46.36% at 48 h. Flow cytometry results showed that TcdB could induce the apoptosis of SW480 cells in a time-concentration dependent manner and a 20.83% apoptosis rate was induced by 800 ng/ml of TcdB at 48 h. Conclusions TcdB could inhibit the proliferation and induce the apoptosis of colon cancer SW480 cells, and the possible mechanisms might be relate to the initiation of mitochondrial apoptosis pathway.

OBJECTIVE: To assess the effect of ergonomic factor load on work-related musculoskeletal disorders(WMSDs) in shipyard workers. METHODS: A total of 751 shipyard workers were selected as the research subjects using judgment sampling method. The exposure level of adverse ergonomic factors was assessed using the Quick Exposure Check method. The prevalence of WMSDs was investigated using the revised Musculoskeletal Disorders Investigating Questionnaire of our research group, and the relationship between them was analyzed. RESULTS: The proportions of high or very high level of work load exposure to the neck, back, shoulder and hand in shipyard workers from high to low were 66.4%, 63.5%, 59.8% and 43.7%(P<0.01) respectively. The proportions of occupational stress, driving, vibration and working rhythm at high or very high exposure level were 20.0%, 4.1%, 22.9% and 3.2%, respectively. The prevalence of WMSDs in four body parts of shipyard workers from high to low was the back, neck, hand and shoulder(the prevalence were 44.2%, 31.2%, 26.9% and 26.6%, respectively, P<0.01). After excluding the influence of confounding factors, multiple logistic regression analysis showed that the higher the labor load exposure level and longer of the vibration tool using, the higher the risk of shoulder WMSDs [odds ratio(OR) and 95% confidence interval(CI) were 1.25(1.04-1.51) and 1.33(1.05-1.69), respectively, P<0.05]. The higher the level of occupational stress, the higher the risk of back and neck WMSDs [OR(95%CI) was 1.29(1.05-1.58) and 1.42(1.15-1.77), respectively, P<0.05]. CONCLUSION: There was a dose-effect relationship between the exposure level of shoulder load, the time of using vibration tools and the shoulder WMSDs, and there was a dose-effect relationship between the occupational stress level and the WMSDs in the back and neck.

Objective:To study the differences of different signal processing method of surface electromyography (sEMG) in judging muscle fatigue.Methods:From July to October 2019, based on the model of simulated manual lifting operation, the original sEMG signals from 13 volunteers of brachial radial muscle, brachial two-headed muscle, triangle muscle, left vertical spine muscle, right vertical spine muscle and lateral femoral muscle were collected in the operation activities. Three different electromyography signal processing methods (all signal from motion beginning to the end, peak signal and ehe specified motion signal) were used to analyze the original data in time domain (RMS) and frequency domain (MDF) , the data difference between different electromyography signal processing methods was analyzed by using Wilcoxon rank and sum test and nonlinear curve fitting method.Results:The age of the subjects of the simulated lifting operation was (24.31±2.02) years old, height (173.78±4.84) cm, weight (66.28±5.58) kg, body mass index (BMI) 21.94±1.58. The thickness of triceps skinfold was (14.08±4.86) mm, and the thickness of the skin fold under the scapula was (15.54±3.59) mm. After processing the original signal data by using different sEMG signal interception methods, the normality test, Levene's test, and the Wilcoxon test showed that, except for the MDF index of the brachial two-headed muscle, the differences in the RMS and MDF signals of the other muscles were statistically significant ( P<0.016) . The all signal processing method dealed with data distribution dispersion better than other methods, and the rate of change of RMS signal slope was higher than other methods. Non-linear regression results showed that all signal processing method had low volatility in processing data, and the regression equation had a high degree of fit. Conclusion:Different electromyography signal processing methods have differences. The all signal processing method which intercepts from starting point to the end point of action cycle has the least data volatility, and electromyography time domain and frequency domain index with the highest sensitivity of time, which is suitable for the application of surface electromyography to judge muscle fatigue in dynamic and complex operations.

Objective:To study the differences of different signal processing method of surface electromyography (sEMG) in judging muscle fatigue.Methods:From July to October 2019, based on the model of simulated manual lifting operation, the original sEMG signals from 13 volunteers of brachial radial muscle, brachial two-headed muscle, triangle muscle, left vertical spine muscle, right vertical spine muscle and lateral femoral muscle were collected in the operation activities. Three different electromyography signal processing methods (all signal from motion beginning to the end, peak signal and ehe specified motion signal) were used to analyze the original data in time domain (RMS) and frequency domain (MDF) , the data difference between different electromyography signal processing methods was analyzed by using Wilcoxon rank and sum test and nonlinear curve fitting method.Results:The age of the subjects of the simulated lifting operation was (24.31±2.02) years old, height (173.78±4.84) cm, weight (66.28±5.58) kg, body mass index (BMI) 21.94±1.58. The thickness of triceps skinfold was (14.08±4.86) mm, and the thickness of the skin fold under the scapula was (15.54±3.59) mm. After processing the original signal data by using different sEMG signal interception methods, the normality test, Levene's test, and the Wilcoxon test showed that, except for the MDF index of the brachial two-headed muscle, the differences in the RMS and MDF signals of the other muscles were statistically significant ( P<0.016) . The all signal processing method dealed with data distribution dispersion better than other methods, and the rate of change of RMS signal slope was higher than other methods. Non-linear regression results showed that all signal processing method had low volatility in processing data, and the regression equation had a high degree of fit. Conclusion:Different electromyography signal processing methods have differences. The all signal processing method which intercepts from starting point to the end point of action cycle has the least data volatility, and electromyography time domain and frequency domain index with the highest sensitivity of time, which is suitable for the application of surface electromyography to judge muscle fatigue in dynamic and complex operations.