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Objective To survey the prevalence of lower extremity musculoskeletal disorders (MSDs) among Chinese manufacturing workers, and to identify the associated factors. Design Observational study with cross-sectional design. Setting A self-administered questionnaire survey was conducted in four manufacturing factories in China. Participants 7908 manufacturing workers were included in this study after excluding non-conforming personnel. Outcome measures Individual and work-related information, and MSDs in the whole leg and knee region were measured by the anonymous self-administered questionnaire. Individual and work-related factors associated with MSDs and their effects were identified through multivariate logistic regression. Results Of all respondents, 3241 (41.0%) reported having had lower extremity MSDs in the recent 12 months, and for the knees, ankles/feet and hips/thighs were 29.5%, 23.9% and 16.7%, respectively. After confounder-adjusted single-factor analysis, 22 variables (of 24) were significantly related to the disorders. Factors like always kneeling/squatting for long periods, always standing for long periods and often lifting in an uncomfortable position were shown to have higher risks, with ORs of 2.77 (95% CI: 2.33 to 3.30), 2.30 (1.96 to 2.69) and 2.25 (2.04 to 2.47). Comparable results were found on knee disorders. The final model included 15 variables of demography, biomechanics and work organisation. The following factors showed increased risks of lower extremity MSDs: being female, being older, longer working years, higher body mass index (BMI), keeping the same posture for a long time, awkward position, shift work and monotonous work. Whereas having enough breaks reduced the risk. Conclusion The prevalence of lower extremity MSDs among Chinese manufacturing workers is high. The most commonly affected body regions were the knees and ankles/feet. Multiple factors were found associated with lower extremity MSDs including age, BMI, work experience, work, QC 20220228

BackgroundMusculoskeletal disorders (MSDs) are critical occupational and social problems. With the improvement of production mechanization and automation, and the widespread application of computers, more occupations are exposed to static postures and load. This study explored the role of inflammation in the association between static postures exposure and MSDs. MethodsThis study adopted a prospective nested case-control design in which 66 lower back MSDs cases and 66 healthy controls were selected from a cohort study of university employees. The personal information, postural load, musculoskeletal symptoms, pressure pain thresholds (PPTs), and inflammatory cytokines were collected. Logistic and linear regressions were used to investigate the association among postural load, inflammatory cytokines, and lower back MSDs. Mediation analysis was used to calculate the mediation effect. ResultsThe results of logistic and linear regressions showed that postural load and inflammatory cytokines were positively associated with lower back MSDs (P < 0.05), and postural load was positively associated with inflammatory cytokines (P < 0.05). Further, mediation analysis showed that the mediation effect of postural load on the lower back MSDs through TNF-alpha was 0.073 (95%CI: 0.025-0.128), and the mediation effect of posture load on the lower back MSDs through IL-6 was 0.098 (95%CI: 0.041-0.179), respectively. ConclusionStatic postures were associated with the occurrence of MSDs through inflammatory cytokines, and low-level inflammation may be a critical early event in the generation of MSDs. This study may help bridge the gap of potential mechanisms linking static postures to increased risks of MSDs, and provide new evidence for targeted protection against the global increasing MSDs., QC 202201111

Leaching of scheelite ore with phytate is a novel and clean hydrometallurgical method of isolating tungsten, which achieves efficient decomposition under atmospheric pressure. However, realising the separation and recycling of tungstate and phytate has become an additional and subsequent problem, which had not been encountered in the traditional tungsten metallurgical process. In determining ways to overcome this obstacle, ion exchange methods exhibit promising routes to separate tungstate and phytate. Before performing this new method, it is prudent to study the kinetics of the ion exchange process. The effects of WO3 concentration, phytate concentration, resin particle size, and reaction temperature were investigated. Results show that a pseudo-second-order model can describe the adsorption kinetic behaviour of phytate and tungstate in the mixed solution. The apparent activation energies of WO3 and phytate, based on the Arrhenius expression, were calculated as 21.4 kJ/mol and 21.8 kJ/mol, indicating that the adsorption processes of phytate and tungstate are diffusion-controlled. (Authors.), Leaching of scheelite ore with phytate is a novel and clean hydrometallurgical method of isolating tungsten, which achieves efficient decomposition under atmospheric pressure. However, realising the separation and recycling of tungstate and phytate has become an additional and subsequent problem, which had not been encountered in the traditional tungsten metallurgical process. In determining ways to overcome this obstacle, ion exchange methods exhibit promising routes to separate tungstate and phytate. Before performing this new method, it is prudent to study the kinetics of the ion exchange process. The effects of WO3 concentration, phytate concentration, resin particle size, and reaction temperature were investigated. Results show that a pseudo-second-order model can describe the adsorption kinetic behaviour of phytate and tungstate in the mixed solution. The apparent activation energies of WO3 and phytate, based on the Arrhenius expression, were calculated as 21.4 kJ/mol and 21.8 kJ/mol, indicating that the adsorption processes of phytate and tungstate are diffusion-controlled. (Authors.)

Work-related musculoskeletal injuries are one of the major occupational health issues of the workers, especially low back pain (LBP). The aim of this study was to survey the prevalence of LBP among manufacturing workers and to identify associations of individual and work-related factors with LBP. A cross-sectional questionnaire study was performed with 1173 participating manufacturing workers. The questionnaire included individual factors, psychosocial and physical exposures, and musculoskeletal discomfort. It was analyzed by logistic regression and structural equation modeling (SEM). The 1-year prevalence of LBP among Chinese manufacturing workers was 33.6%. Logistic regression analysis showed that job tenure, awkward postures, vibration and job demand were positively-while social support and job control were negatively associated with LBP (p < 0.05). The SEM results indicated that, as shown in other studies, job types, job tenure, postural load, high job demand, low job control and vibration were directly associated with LBP, but also that job types, high job demand, low social support and vibration may have indirect effects on LBP-mediated by postural load., QC 20210331