Objective: To investigate the prevalence and risk factors of occupational musculoskeletal disorders among workers in heavy-duty automobile parts factories in Beijing Municipality, so as to provide insights into development of effective interventions for occupational musculoskeletal disorders. Methods: The workers in three heavy-duty automobile truck parts factories in Beijing Municipality were recruited using the convenient sampling method during the period from May 2019 to October 2020. Subjects' demographic characteristics, type of job and prevalence of occupational musculoskeletal disorders at various sites were collected using self-designed electronic questionnaires, and the factors affecting the development of occupational musculoskeletal disorders were identified using a multivariable logistic regression model. Results: A total of 264 workers were enrolled, including 260 males (98.48%) and 4 females (1.52%). The participants had a mean age of (31.71±6.13) years, and mean duration of (7.51±5.25) years at current position, and mechanical technician was the major type of work (129 workers, 48.86%). The prevalence of occupational musculoskeletal disorders was 70.08% among the participants, and high prevalence of occupational musculoskeletal disorders was found in the lower back/waist (41.28%), shoulder (40.15%), neck (39.02%) and upper back (33.33%). Multivariable logistic regression analysis identified females (OR=1.280, 95%CI: 1.021-1.602) and head-down posture at work (OR=2.644, 95%CI: 1.034-6.763) as risk factors for occupational musculoskeletal disorders at neck; females (OR=1.633, 95%CI: 1.624-2.117), sheet metal workers, mechanical technicians and painters (OR: 5.811-10.452, 95%CI: 1.205-54.027), working in an uncomfortable posture (OR：1.376-7.749, 95%CI: 1.034-27.270) and frequent working overtime (OR=2.081, 95%CI: 1.192-4.137) as risk factors for occupational musculoskeletal disorders at shoulder; and sheet metal workers, mechanical technicians and painters (OR: 8.760-11.948, 95%CI: 1.630-66.927), working in an uncomfortable posture (OR：4.067-12.185, 95%CI: 1.332-47.523) and frequent working overtime (OR=2.201, 95%CI: 1.142-4.244) as risk factors for occupational musculoskeletal disorders at waist/back. Conclusions The prevalence of occupational musculoskeletal disorders is high among workers in heavy-duty automobile parts factories, which mainly occur at shoulder, neck, waist and back. Type of work, working posture and working duration are main factors affecting the development of occupational musculoskeletal disorders.

Bus drivers, as an important occupational group in urban public transportation system, are prone to suffer from work-related musculoskeletal disorders (WMSDs) due to prolonged fixed postures and repetitive movements. The T/WSJD 14.9-2024 Ergonomic Guidelines for the Prevention of Work-related Musculoskeletal Disorders: Part 9: Bus Driving Work is a recommended standard developed to prevent WMSDs among bus drivers. This standard, guided by the principles of T/WSJD 14.1-2020 Ergonomic Principle for the Prevention of Work-related Musculoskeletal Disorders: Part 1: General Principles, is based on a preliminary work of comprehensive review of domestic and international research, workplace on-site surveys and questionnaires, data analysis, and factor identification. It defines the scope of application, identifies relevant risk factors and potential affected body parts, and offers ergonomic solutions in the form of intervention examples. The issuance of this guideline as a organization standard will facilitate the promotion and implementation of intervention measures.

Objective: To study the relationship between XRCC1 gene polymorphism and DNA damage in peripheral blood lymphocytes of workers exposed to coal tar pitch. Methods: 203 coal tar asphalt device operation area workers (exposure group) and 76 logistics management personnel (control group) as the research ob-ject, determination of 1-hydroxypyrene concentrations in the urine as polycyclic aromatic hydrocarbons expo-sure dose, using the alkaline comet assay evaluation a peripheral blood lymphocyte DNA damage degree, using TaqMan MGB real time PCR method to detect XRCC1 gene 3 loci (XRCC1-194, XRCC1-280 and XRCC1-399) single nucleotide polymorphism. Results: No significant differences was observed in age, sex, smoking and alco-hol consumption between the two groups (P>0.05). The level of 1-OHP in the exposed group was significantly higher than that in the control group (1.27±0.93 μg/g creatinine) (P<0.05). The comet Olive tail moment level (3.21±0.93) in the peripheral blood lymphocytes of the exposed group was significantly higher than that in the control group (0.94 ± 0.39) (P<0.05). There was no significant difference in genotype distribution of XRCC1-194, XRCC1-280 and XRCC1-399 between the two groups (P>0.05). There was a significant correlation be-tween the XRCC1-280 locus gene polymorphism and comet Olive tail moment in the exposure group (P<0.05) af-ter adjustment for sex, age, smoking rate, drinking rate, length of service and urinary 1-OHP concentration. The comet Olive tail moment level of GG individuals carrying wild homozygous genotype was significantly lower than that of individuals carrying heterozygous genotype GA and carrying mutant homozygous genotype AA (P< 0.05) , and the difference was statistically significant (P<0.05) The comet Olive tail moment level of heterozy-gous genotype GA was significantly lower than that of genotype AA with mutational homozygous genotype AA (P<0.05) , and the difference was statistically significant (P<0.05). Conclusion Arg280His locus polymor-phism of XRCC1 gene may influence the DNA damage level of peripheral blood lymphocytes induced by occupational exposure to coal tar pitch.

Objective: To evaluate the viability of gasoline engine exhaust (GEE) with different particle sizes on human lung cell line BEAS-2B in vitro by air-liquid interface (ALI) . Methods: GEE were collected with a Tedlar bag and their particulate matter (PM) number, surface and mass concentration in three kind of GEE (filtered automobile exhaust, non-filtered automobile exhaust and motorcycle exhaust without three-way catalytic converter) were measured by two type of particle size spectrometer including TSI-3321 and SMPS-3938. Five groups were included, which divided into blank control group, clean air group, filtered automobile exhaust group, non-filtered automobile exhaust group and motorcycle exhaust without three-way catalytic converter group. Except the blank control group, BEAS-2B cells, cultured on the surface of Transwells, were treated with clean air or GEE by ALI method at a flow rate of 25 ml/min, 37 ℃ for 60 min in vitro. CCK-8 cytotoxicity test kit was used to determine the cell relative viability of BEAS-2B cells. Results: In the filtered automobile exhaust, non-filtered automobile exhaust and motorcycle exhaust without three-way catalytic converter, high concentrations of fine particles can be detected, but the coarse particles only accounted for a small proportion, and the sequence of PM concentration was motorcycle exhaust without three-way catalytic converter group> non-filtered automobile exhaust group> filtered automobile exhaust group (P<0.001) . Compared with the clean air group, the cell relative viability in the 3 GEE-exposed groups were significantly lower (P<0.001) . Among the comparisons of GEE exposure groups with different particle size spectra, the sequence of the cell relative viability was filtered automobile exhaust group >non-filtered automobile exhaust group> motorcycle exhaust without three-way catalytic converter group (P<0.001) . When took the clean air control group as a reference, the mean of the cell relative viability in the filtered automobile exhaust group, non-filtered automobile exhaust group and motorcycle exhaust without three-way catalytic converter group, was decreased by 26.34%, 36.00% and 49.59%, respectively. Conclusion GEE with different particle size spectra could induce different levels of toxic effects to the human lung cells BEAS-2B by ALI. After lowering the concentration of particles in the GEE and using the three-way catalytic converter could obviously improve the survival rate of lung cells.

Objective: The spatial distribution model of particulate matter based on time change in a specific place was established to analyze the spatial and temporal distribution characteristics and movement of particulate matter. Methods: A convenience store was selected as the research subject. The micro-climate and particle number concentration (PNC) of the site were detected, and numerical simulation was carried out by computational fluid dynamics (CFD) simulation method. Based on the discrete phase model, the temporal and spatial distribution characteristics and movement rules of simulated particles were analyzed. Results: The wind speed at the entrance of the convenience store was low and almost unchanged during the detection, while the wind speeds outside and inside outlets were high and changed sharply. The PNC of particle size of 0.02-1.00 μm was higher than that of particle size >1.00 μm (all P<0.05). The PNC with particle size of 0.02-1.00 μm from high to low were checkout counter, entrance, outer outlet and inner outlet (all P<0.05). The PNC of the checkout counter and entrance varies greatly, while the PNC of the outer outlet and inner outlet was relatively steady. The CFD simulation results showed that particles exhaled by individuals near the entrance of the checkout counter of the convenience store could be expelled outdoors more quickly with the influence of airflow. However, particles exhaled by individuals in the middle of the shelves remained suspended indoors for a longer period of time compared to those near the checkout counter. Particles emitted from the air conditioning outlet diffuse throughout the entire store and reach a steady state in 300 seconds. Conclusion: The particulate matter in the convenience store was mainly small particle with the size less than 1.00 μm. The residence time, downward trend and number of suspended particulates of human exhaled particles were related to air flow. The particulates escaped from the air conditioner could quickly spread to almost the entire convenience store.

Objective:To explore the index system and weight of occupational stress risk assessment for civil aviation air traffic controllers (ATC) .Methods:In October 2018, a total of 489 ATC staff from an air traffic administration bureau were selected by cluster sampling. Through ATC questionnaire survey, the basic information, the influencing factors of occupational stress and the degree of occupational stress were understood. Based on the order relation analysis method (GL method) , the influencing factors of ATC occupational stress in civil aviation are evaluated. The fuzzy relation synthesis principle is applied to carry out multi-level fuzzy evaluation on the subordinate degree of occupational stress risk, and the ATC occupational stress risk evaluation system model is established. The weight of each index in the index system is determined, Establish a three-level comprehensive evaluation index system for ATC occupational stress risk, and quantify the occupational stress risk, Each Civil Aviation ATC occupational stress index corresponds to different degree of stress.Results:The influence degree of ATC occupational stress from heavy to light is: work factor, psychological factor, event factor, management factor, physiological factor, equipment factor and environmental factor (weight value is 0.2652, 0.2265, 0.1832, 0.1253, 0.1154, 0.045 5, 0.038 9 respectively) .Conclusion:GL method can be used to comprehensively and quantitatively evaluate the occupational stress risk of Civil Aviation ATC, which may be a feasible way to evaluate the occupational stress risk of Civil Aviation ATC.

Objective:To explore the index system and weight of occupational stress risk assessment for civil aviation air traffic controllers (ATC) .Methods:In October 2018, a total of 489 ATC staff from an air traffic administration bureau were selected by cluster sampling. Through ATC questionnaire survey, the basic information, the influencing factors of occupational stress and the degree of occupational stress were understood. Based on the order relation analysis method (GL method) , the influencing factors of ATC occupational stress in civil aviation are evaluated. The fuzzy relation synthesis principle is applied to carry out multi-level fuzzy evaluation on the subordinate degree of occupational stress risk, and the ATC occupational stress risk evaluation system model is established. The weight of each index in the index system is determined, Establish a three-level comprehensive evaluation index system for ATC occupational stress risk, and quantify the occupational stress risk, Each Civil Aviation ATC occupational stress index corresponds to different degree of stress.Results:The influence degree of ATC occupational stress from heavy to light is: work factor, psychological factor, event factor, management factor, physiological factor, equipment factor and environmental factor (weight value is 0.2652, 0.2265, 0.1832, 0.1253, 0.1154, 0.045 5, 0.038 9 respectively) .Conclusion:GL method can be used to comprehensively and quantitatively evaluate the occupational stress risk of Civil Aviation ATC, which may be a feasible way to evaluate the occupational stress risk of Civil Aviation ATC.

Objective: To investigate the effect of coal tar pitch occupational exposure on the cytogenetic damage. Methods: In July 2015, 691 workers exposed to coal tar pitch were selected as contact group. The administrative and the support crew 201 cases were selected as control group. Detect the tail DNA% and tail moment in peripheral blood lymphocyte as DNA damage degree by single cell gel electrophoresis (SCGE) . Detect the concentration of the metabolic product in urine by HPLC/MC as exposure levels. Results: The contact group were significantly higher than the control group in tail DNA% (contact group14.44%, control group 11.17%) and olive tail moment (contact group 2.85 μm, control group 1.95 μm) . The smoking one (contact group18.51%, control group13.43%) were significantly higher than the group not smoking (contact group12.69%, control group 11.71%) in tail DNA%. The coal tar pitch content in the air of workplace have correlation with worker, stail DNA% (r_s=0.10) and olive tail moment (r_s=0.11) . Conclusion Occupational exposure to coal tar pitch and smoking can cause cytogenetic damage to workers.

Objective To investigate the prevalence and related factors of musculoskeletal diseases in nurses by means of qualitative and quantitative research, and to have a discussion on the inner experiences of nurses. Methods 1 012 clinical nurses, from one hospital during March 2019 to May 2019, were selected as research objects by convenience sampling method. The Nordic musculoskeletal disease questionnaire was used for investigation,and SPSS 21.0 was used for statistical analysis. In the qualitative study,5 ICU nurses were selected by objective sampling method. Data were collected by semi-structured interview method,and analyzed by content analysis method. Results The annual prevalence rate of musculoskeletal diseases in clinical nurses was mainly in the neck (53.2%, 538/1 012), followed by the waist and back (48.5%, 491/1 012), hip and leg (45.2%, 457/1 012). Logistic regression analysis of neck related factors showed that BMI (P=0.039), repeated operation for one minute (P=0.007), and staff shortage in the Department (P=0.027) were the influencing factors of musculoskeletal diseases. Qualitative research extracted the following two themes:negative psychological experience of nurses under high workload and positive psychological experience of nurses. Conclusion The prevalence of neck is the highest among those of other musculoskeletal diseases in clinical nurses, which is related to many related factors. In the professional environment of nurses, nurses have high self-protection willingness and ability. It is suggested to strengthen support from hospital, family and other aspects, reduce the prevalence rate, and improve the quality of work and family life of nurses.

Objective To investigate the changes of brain networks function in patients with primary dysmenorrhea(PDM)during menstruation based on topological attributes of brain network.Methods Brain resting-state functional MRI of 57 PDM patients(PDM group)and 50 healthy women(health control[HC]group)were prospectively collected within the first or the second day of menstruation.Clinical scores were obtained and compared between groups.Results Visual analogue scale,cox menstrual symptom scale,self-rating anxiety scale and self-rating depression scale scores in PDM group were all higher than those in HC group(all P＜0.05).At the sparsity of 0.04-0.50,brain networks in both groups conformed to the small world attribute characteristics,and no significant difference of global attributes of brain network was found between groups(all P＞0.05).The node efficiency(Ne)and node degree(Dc)of bilateral posterior cingulate gyrus(PCG),as well as De and node betweenness(Bc)of left middle frontal gyrus(MFG)in PDM group were all higher than those in HC group,while Ne and De of left inferior temporal gyrus in PDM group were lower than those in HC group(all P＜0.01).Compared with HC group,the functional connections between left PCG and right calcarine fissure and surrounding cortex,right lingual gyrus and left MFG,as well as between right PCG and right dorsolateral superior frontal gyrus and left MFG,between right insula and left middle occipital gyrus enhanced in PDM group(all P＜0.001).Conclusion In PDM patients,local brain networks function such as default mode network,central executive network and salience network were over-activated during menstruation,yet the overall brain network still had good coordination and organization.