Objective:To explore the effect of refractory ceramic fibers (RCFs) on the serum Clara cell protein 16 (CC16) and surfactant protein D (SP-D) levels in Wistar rats.Methods:In October 2020, 96 healthy adult male Wistar rats were randomly divided into control group (equal volume of normal saline) , low-dose group (5 mg/ml RCFs) , medium-dose group (10 mg/ml RCFs) and high-dose group (20 mg/ml RCFs) , and subjected to non-exposure tracheal instillation. After intraperitoneal anesthesia, the rats were instilled with 200 μl of RCFs suspension or normal saline, once every 3 days for a total of 4 times. At 7, 14, 28, and 90 days after exposure, 6 rats were sacrificed by blood sampling through the abdominal aorta. The organs were separated, histopathological changes of lungs were observed and lung injury scores were performed. The contents of serum CC16 and SP-D were determined by enzyme-linked immunosorbent assay (ELISA) .Results:RCFs could cause inflammatory cells in rat lung tissues, widening of the lung septum and destruction of alveolar structure. 7 days after exposure, the lung injury scores of rats in each dose group were higher than control group, and the lung injury score of the high-dose group was higher than low-dose group ( P<0.05) . 14 and 90 days after exposure, the lung injury scores of the medium-dose and high-dose groups were higher than control group ( P<0.05) . 28 days after exposure, the lung injury score of the high-dose group was higher than control group ( P<0.05) . 7 days after exposure, the serum CC16 and SP-D concentrations of rats in the medium-dose and high-dose groups were significantly higher than control and low-dose groups ( P<0.05) . 28 days after exposure, the serum CC16 concentrations of rats in the low-dose and medium-dose groups were significantly lower than those of the control and high-dose groups ( P<0.05) . After 90 days of exposure, the serum CC16 concentrations of rats decreased with the increase of the exposure dose ( F=28.853, P<0.01) , and the concentrations of SP-D increased with the increase of the exposure dose ( F=25.636, P<0.01) . Conclusion:RCFs exposure may cause certain damage to rat Clara cells and alveolar-capillary barrier. The severity of lung injury can be indirectly understood through the dynamic changes of serum CC16 and SP-D.

Objective:To explore the effect of refractory ceramic fibers (RCFs) on the serum Clara cell protein 16 (CC16) and surfactant protein D (SP-D) levels in Wistar rats.Methods:In October 2020, 96 healthy adult male Wistar rats were randomly divided into control group (equal volume of normal saline) , low-dose group (5 mg/ml RCFs) , medium-dose group (10 mg/ml RCFs) and high-dose group (20 mg/ml RCFs) , and subjected to non-exposure tracheal instillation. After intraperitoneal anesthesia, the rats were instilled with 200 μl of RCFs suspension or normal saline, once every 3 days for a total of 4 times. At 7, 14, 28, and 90 days after exposure, 6 rats were sacrificed by blood sampling through the abdominal aorta. The organs were separated, histopathological changes of lungs were observed and lung injury scores were performed. The contents of serum CC16 and SP-D were determined by enzyme-linked immunosorbent assay (ELISA) .Results:RCFs could cause inflammatory cells in rat lung tissues, widening of the lung septum and destruction of alveolar structure. 7 days after exposure, the lung injury scores of rats in each dose group were higher than control group, and the lung injury score of the high-dose group was higher than low-dose group ( P<0.05) . 14 and 90 days after exposure, the lung injury scores of the medium-dose and high-dose groups were higher than control group ( P<0.05) . 28 days after exposure, the lung injury score of the high-dose group was higher than control group ( P<0.05) . 7 days after exposure, the serum CC16 and SP-D concentrations of rats in the medium-dose and high-dose groups were significantly higher than control and low-dose groups ( P<0.05) . 28 days after exposure, the serum CC16 concentrations of rats in the low-dose and medium-dose groups were significantly lower than those of the control and high-dose groups ( P<0.05) . After 90 days of exposure, the serum CC16 concentrations of rats decreased with the increase of the exposure dose ( F=28.853, P<0.01) , and the concentrations of SP-D increased with the increase of the exposure dose ( F=25.636, P<0.01) . Conclusion:RCFs exposure may cause certain damage to rat Clara cells and alveolar-capillary barrier. The severity of lung injury can be indirectly understood through the dynamic changes of serum CC16 and SP-D.

Objective:To evaluate the quality and item characteristics of the Brief Job Stress Questionnaire (BJSQ) among employees in manufacturing and service industries.Methods:From December 2021 to December 2022, a total of 2077 employees from 4 manufacturing and service enterprises in Beijing were selected by the method of combining purpose sampling and convenience sampling. The Chinese version of BJSQ was used to carry out a survey on occupational stress from 57 items in 4 dimensions including job stress factors, stress response, social support factors and satisfaction. Classical test theory (CTT) was used to analyze the validity and reliability of the questionnaire. The Semejima hierarchical response model in item response theory (IRT) was used to analyze the differentiation a, difficulty coefficient b and information content of each item.Results:Among the 2077 subjects, the age M ( Q1, Q3) was 33 (28, 37) years old, and the working age M ( Q1, Q3) was 4 (2, 8) years. There were 723 (34.8%) people in manufacturing industry and 1354 (65.2%) people in service industry. Eleven common factors were extracted by exploratory factor analysis, with a cumulative variance contribution rate of 62.823%, the variance of the common factors of each entry ranging from 0.451 to 0.865, and the range of factor loading values from 0.413 to 0.825, with 5 items having cross-loadings. The results of the validation factor analysis showed that the model fit indexes of root means square error of approximation was 0.055, comparative fit index was 0.950, Tucker Lewis index was 0.948, and standardized root mean square was 0.066. Content validity results showed that the total scores of the Chinese version of the BJSQ were positively correlated with the scores of the 4 dimensions ( rs=0.487-0.936, P<0.05) . The results of the reliability analysis showed that the Cronbach's alpha coefficient for the total questionnaire was 0.945, and the Cronbach's alpha coefficients of job stress factors, stress response and social support factors were 0.775, 0.957, and 0.830, respectively. The Spearman-Brown coefficient for the total questionnaire was 0.866, and for the 3 dimensions, it was 0.572, 0.882 and 0.772. The results of IRT analysis showed that only 1 of the 57 items had a differentiation a-value<0.30, the difficulty coefficient b-value of each item ranged from -12.02 to 11.09, of which 8 items had a difficulty coefficient that was too high, 3 items had a difficulty coefficient that was too low, and 3 items did not meet the requirements, and the average amount of information in each item ranged from 0.022 to 2.566, and there were 47 items with average amount of information>0.088 (5/57) . Conclusion:The Chinese version of BJSQ has good reliability and validity in the typical occupational groups of manufacturing and service industries in China, and most of the items have good performance, but some items still need to be further improved and optimized or deleted.

Objective:To evaluate the quality and item characteristics of the Brief Job Stress Questionnaire (BJSQ) among employees in manufacturing and service industries.Methods:From December 2021 to December 2022, a total of 2077 employees from 4 manufacturing and service enterprises in Beijing were selected by the method of combining purpose sampling and convenience sampling. The Chinese version of BJSQ was used to carry out a survey on occupational stress from 57 items in 4 dimensions including job stress factors, stress response, social support factors and satisfaction. Classical test theory (CTT) was used to analyze the validity and reliability of the questionnaire. The Semejima hierarchical response model in item response theory (IRT) was used to analyze the differentiation a, difficulty coefficient b and information content of each item.Results:Among the 2077 subjects, the age M ( Q1, Q3) was 33 (28, 37) years old, and the working age M ( Q1, Q3) was 4 (2, 8) years. There were 723 (34.8%) people in manufacturing industry and 1354 (65.2%) people in service industry. Eleven common factors were extracted by exploratory factor analysis, with a cumulative variance contribution rate of 62.823%, the variance of the common factors of each entry ranging from 0.451 to 0.865, and the range of factor loading values from 0.413 to 0.825, with 5 items having cross-loadings. The results of the validation factor analysis showed that the model fit indexes of root means square error of approximation was 0.055, comparative fit index was 0.950, Tucker Lewis index was 0.948, and standardized root mean square was 0.066. Content validity results showed that the total scores of the Chinese version of the BJSQ were positively correlated with the scores of the 4 dimensions ( rs=0.487-0.936, P<0.05) . The results of the reliability analysis showed that the Cronbach's alpha coefficient for the total questionnaire was 0.945, and the Cronbach's alpha coefficients of job stress factors, stress response and social support factors were 0.775, 0.957, and 0.830, respectively. The Spearman-Brown coefficient for the total questionnaire was 0.866, and for the 3 dimensions, it was 0.572, 0.882 and 0.772. The results of IRT analysis showed that only 1 of the 57 items had a differentiation a-value<0.30, the difficulty coefficient b-value of each item ranged from -12.02 to 11.09, of which 8 items had a difficulty coefficient that was too high, 3 items had a difficulty coefficient that was too low, and 3 items did not meet the requirements, and the average amount of information in each item ranged from 0.022 to 2.566, and there were 47 items with average amount of information>0.088 (5/57) . Conclusion:The Chinese version of BJSQ has good reliability and validity in the typical occupational groups of manufacturing and service industries in China, and most of the items have good performance, but some items still need to be further improved and optimized or deleted.

Objective To analyze the evaluation results of health enterprises in Beijing City and their influencing factors. Methods A total of 40 enterprises that passed the health enterprise evaluation in Beijing from 2021 to 2022 were selected as the study subjects using the judgment sampling method. The total evaluation scores and influencing factors were analyzed based on the size, nature, industry classification, and establishment time of the enterprises. Results The total evaluation score of the 40 health enterprises was (553.1±18.4) points. Scores for the primary evaluation indicators, including management organization and system, occupational disease prevention measures, health environment, health promotion measures, prevention measures for occupational stress caused damage, and musculoskeletal injury prevention measures, were (94.0±4.8), (94.0±4.3), (94.5±3.8), (89.7±4.8), (89.6±4.6), and (91.4±5.9) points, respectively. The result of multiple linear regression analysis showed that, large enterprises had higher total evaluation scores than medium enterprises and micro and small enterprises after controlling for confounding factors such as industry classification and establishment time (all P<0.10). The total evaluation scores of private enterprises and foreign-funded enterprises were lower than that of state-owned or state-participated enterprises (all P<0.10). Conclusion Enterprise size and nature are influencing factors for the total evaluation score of health enterprises. It is necessary to enhance resource and policy support for medium-sized, micro and small enterprises and private enterprises to improve the development of the health enterprises.

{L-End}Objective To study and develop a suitable scale to identify and assess risks of occupational stress in workplaces of enterprises, and to explore the establishment of a workplace occupational stress risk assessment method aimed at guiding enterprises to improve working conditions based on the electronics industry in Beijing City. {L-End}Methods The initial version of the Workplace Occupational Stress Risk Assessment Scale (WOSRAS) was constructed based on literature review and expert evaluation. A total of 1 284 employees from four electronics enterprises in Beijing City were selected as the research subjects using a convenient sampling method. Item analysis and exploratory factor analysis were used to determine the final items of the scale and test its reliability and validity. The method of percentile norms was used to establish risk assessment method for the electronics industry workplace and its stress sources, and the cut-off values of low, medium, high risk was graded by the 50th and 80th percentiles of the total score and the score of each dimension of the risk assessment scale. {L-End}Results i) Based on item analysis and exploratory factor analysis, a WOSRAS consisting of six dimensions and 23 items was constructed, which could explain 63.2% of the total variation of occupational stress. The results of confirmatory factor analysis showed that the root mean square error of approximation and standardized root mean square residual were both <0.080, and the comparative fit index and Tucker-Lewis index were both >0.900. The total criterion validity of the scale was 0.816. The total Cronbach's α coefficient of the scale was 0.835, and the Spearman-Brown coefficient was 0.802. ii) The cut-off values of WOSRAS scores for high, medium and low risk in electronics industry were <53.0, 53.0-60.0 and >60.0,respectively. According to the result, the workplace stress risk levels of the production, research and development, and logistics departments of the electronics industry in Beijing were medium risk, while the management department was low risk. {L-End}Conclusion The WOSRAS constructed in this study has good reliability and validity. The proposed risk assessment method can reflect the actual risk status of enterprises in the electronic industry and is convenient for widespread application.

{L-End}Objective To explore the suitable methods for individual occupational stress examination and evaluation for workers in China based on the electronics industry. {L-End}Methods A total of 1 164 workers from four electronics enterprises in Beijing City were selected as the research subjects using a convenient sampling method. The Occupational Stress Measurement Scale, which was developed based on the Japanese Brief Job Stress Questionnaire, was used to assess the occupational stress of the research subjects, and test the reliability and validity of the scale. Percentile norms and T-score norms were established, and the T-scores of the three dimensions of stress reaction (psychological reaction and physical symptoms), stress factors, and social support were divided into five stages using the normal distribution method with x¯±0.5 s and x¯±1.5 s, which was used to explore a proposed standard for assessing individual stress levels. {L-End}Results The revised scale consisted of 57 items, which could explain 64.0% of the total variation of occupational stress based on the result of item analysis and exploratory factor analysis. The results of confirmatory factor analysis showed that the model fitted well, with root mean square error of approximation of 0.052, standardized root mean square residual of 0.070, comparative fit index of 0.960, and Tucker-Lewis index of 0.958. The Cronbach's α coefficient of the scale was 0.951, and the Spearman-Brown coefficient was 0.837. Cronbach's α coefficients of the three dimensions ranged from 0.794 to 0.952, and the Spearman-Brown coefficients ranged from 0.737 to 0.850. The scores of the three dimensions of stress reaction, stress factors, and social support were (49.1±13.0), (44.9±7.7), and (18.1±3.6), respectively. Workers in the electronics industry met one of the following items were identified as the high level of occupational stress individuals: i) a score of stress reaction dimension ≥72.0 points; ii) a sum of stress factor and social support dimension scores ≥81.0 points, and a stress reaction dimension score ≥58.0 points. {L-End}Conclusion The Occupational Stress Measurement Scale and the criteria for determining high level of occupational stress can be used to assess the individual occupational stress levels of workers in the electronics industry in China. This method can provide a theoretical basis for the formulation of occupational stress examination and assessment for Chinese workers.

{L-End}Objective To analyze the current status of occupational stress and its influencing factors among workers in pharmaceutical enterprises in Beijing City. {L-End}Methods A total of 860 employees from six pharmaceutical enterprises in Beijing City were selected as the research subjects using convenience sampling method. The Chinese version of the New Brief Job Stress Questionnaire was used to evaluate the occupational stress, and multiple linear regression analysis was used to analyze the influencing factors of occupational stress. {L-End}Results The detection rate of high occupational stress was 1.40% (12/860). The results of multiple linear regression analysis showed that the workers with higher education level and longer length of service had a higher risk of high occupational stress (all P<0.01). Workers who were satisfied with their jobs had a lower risk of high occupational stress than those who were unsatisfied with their jobs (P<0.01). Workers who were satisfied with life had a significantly lower risk of high occupational stress than those who were unsatisfied with life (P<0.01). {L-End}Conclusion The detection rate of high occupational stress in workers of pharmaceutical enterprises is relatively low. Occupational stress is mainly affected by individual factors such as education level and length of service, and work and life satisfaction. Improving job and life satisfaction is helpful to reduce occupational stress level.

Objective:To evaluate the effects of exposure of fine particle matter (PM 2.5) and ozone (O 3) in Beijing as the main pollutants on olfaction of SD rats. Methods:In October 16, 2018, twenty 8-week-old SD rats were randomly divided into two groups, 10 rats in the exposure group and 10 rats in the control group. They were fed in air pollutant exposure system and clean experimental environment respectively, and the concentrations of PM 2.5 and O 3 in each system were measured. The degree of olfaction damage of SD rats at different feeding time was assessed by using the buried food test (BFT). The difference of BFT time between the two groups was analyzed by performing the repeated measures analysis of variance. Results:The results showed that the concentrations of PM 2.5 and O 3 in the exposure group were (22.65±11.47) μg/m 3 and (12.36±5.87) μg/m 3, respectively, while those in the control group were both 0 μg/m 3. The repeated measures analysis of variance showed that the time of BFT in the exposure group was longer than that in the control group ( F=6.49, P=0.031). With the increase of feeding time, the time of BFT was prolonged ( F=61.69, P<0.001). Conclusion:Exposure to PM 2.5 and O 3in the atmosphere might lead to olfaction damage in rats.

Objective:To evaluate the effects of exposure of fine particle matter (PM 2.5) and ozone (O 3) in Beijing as the main pollutants on olfaction of SD rats. Methods:In October 16, 2018, twenty 8-week-old SD rats were randomly divided into two groups, 10 rats in the exposure group and 10 rats in the control group. They were fed in air pollutant exposure system and clean experimental environment respectively, and the concentrations of PM 2.5 and O 3 in each system were measured. The degree of olfaction damage of SD rats at different feeding time was assessed by using the buried food test (BFT). The difference of BFT time between the two groups was analyzed by performing the repeated measures analysis of variance. Results:The results showed that the concentrations of PM 2.5 and O 3 in the exposure group were (22.65±11.47) μg/m 3 and (12.36±5.87) μg/m 3, respectively, while those in the control group were both 0 μg/m 3. The repeated measures analysis of variance showed that the time of BFT in the exposure group was longer than that in the control group ( F=6.49, P=0.031). With the increase of feeding time, the time of BFT was prolonged ( F=61.69, P<0.001). Conclusion:Exposure to PM 2.5 and O 3in the atmosphere might lead to olfaction damage in rats.