Objective To analyze the epidemiological characteristics of occupational diseases caused by physical factors in Guangdong Province from 2013 to 2022, and to evaluate the key risk points of its incidence. Methods The data of newly diagnosed and suspected occupational diseases caused by physical factors in Guangdong Province from 2013 to 2022 were collected from the Occupational Diseases and Hazards Monitoring Information System under China Disease Prevention and Control Information System, and were analyzed retrospectively. The key risk points of occupational diseases caused by physical factors were evaluated. Results A total of 661 cases of occupational diseases caused by physical factors were reported in Guangdong Province from 2013 to 2022, showing an overall increasing trend, with an average annual growth rate of 29.6%. The major occupational diseases caused by physical factors were occupational hand-arm vibration disease and occupational heat stroke, accounting for 59.5% and 39.6%, respectively. The nine prefecture-level cities of Pearl River Delta region accounted for 98.5% of the new cases. The cases were distributed mainly in the manufacturing industry (77.0% of the cases). A total of 294 enterprises were involved in the analysis of newly diagnosed occupational diseases caused by physical factors. Occupational hand-arm vibration cases appeared to be significantly aggregated in specific enterprises, and other disease cases were mostly sporadic. The types of enterprise registration were mainly Hong Kong-, Macao-, and Taiwan-invested enterprises and domestic-funded enterprises, accounting for 53.1% and 41.4%, respectively. In terms of enterprise size, large-scale and small-scale enterprises accounted for 56.5% and 21.4% of cases, respectively. A total of 27.4% of workers with occupational diseases caused by physical factors were identified as suspected occupational diseases before be diagnosed as occupational diseases, all of which were hand vibration disease and heat stroke In the future, attention should be paid to the risks of mass events of occupational hand-arm vibration disease, outbreaks of occupational heat stroke, and missed diagnosis of suspected occupational hand-arm vibration disease. Conclusion Among all occupational diseases caused by physical factors in Guangdong Province, attention should be paid on occupational hand-arm vibration disease and occupational heat stroke. Occupational hand-arm vibration disease has a high risk of group morbidity. Construction workers and sanitation workers have a high potential risk of occupational heat stroke.

Objective: To investigate the characteristics, temporal trend of silicosis, and provide basis for risk assessment and precise prevention and control of occupational diseases. Methods: Using descriptive statistics to analyze the reported cases of silicosis by SPSS 20.0 software. Reported silicosis cases, the constituent ratio, the incidence age and the working age at onset were analyzed by a linear trend test. Analyzing the variation trends of regional, industry, economic type and enterprise scale distributions by the chi-square trend test. Moreover, using Moran's I method for spatial autocorrelation analysis and trend-surface analysis. Results: (1) During 2006 to 2015, Guangdong province had reported 1, 428 cases of silicosis, mainly gathered in Foshan, Zhongshan, Guangzhou, Shenzhen, which included 1391 male cases accounting for 97.41%. And the average incidence age was 45 (39, 51) . The average working age of onset was 9 (5.5, 15) . In economic type distribution, the private economy took the main part, accounting for 59.1%. In enterprise scale distribution, it was dominated by small and medium enterprises (SMEs) , accounting for 32.4% and 37.3% respectively. In industry distribution, most cases were gathered in materials and mining industry, accounting for 32.1% and 22.9% respectively. (2) The number of silicosis cases, the incidence age and the working age of onset showed a rising trend (P<0.01) . Meanwhile, the constituent ratios of medium-sized enterprises and building materials industry were increasing (P<0.05) . The annual variation trends of regional, economic type and age distributions were not statistically significant (P> 0.05) . (3) The spatial distribution trend showed an inverted U type, which was firstly raised and then declined from south to north and from east to west. The distribution characteristic demonstrated some high-high cluster areas, including Chancheng, Nanhai, Shunde, Panyu, Dongguan, Pengjiang, and Zhongshan. While Wuhua showed a high-low outlier form (P<0.01) . Conclusion Silicosis cases, age and working age of onset were on the rise, as well as the industry and enterprise scale distributions of occupational diseases presented a certain trend in Guangdong province from 2006 to 2015. There were high-high cluster and high-low outlier phenomena in spatial distribution with spatial correlation. Therefore, our work of silicosis epidemic trend and distribution may provide some bases for the occupational disease risk assessment and control.

Objective To investigate the level of finger systolic blood pressure (FSBP) in healthy young adults. Methods A total of 28 healthy young adults were selected as the study subjects by convenient sampling method. The FSBP of the study subjects was detected at 30 and 10 ℃, and the FSBP index (F_i) was calculated. Results The FSBP of the study subjects at 30 and 10 ℃ were (102.0±16.5) and (104.4±15.2) mmHg, respectively. The FSBP in male group at 30 and 10 ℃ was (99.6±18.6) and (107.2±17.0) mmHg, respectively. The FSBP in female group at 30 and 10 ℃ was (104.4±13.9) and (101.5±2.8) mmHg, respectively. The results of factorial analysis showed that the interaction between gender and temperature on FSBP was statistically significant (P<0.05). FSBP in male group was higher at 10 than 30 ℃ (P<0.05) and higher than female group at 10 ℃ (P<0.05). There was no statistical significance for the main effect of gender, temperature, finger, or the interaction effect of gender and finger, temperature and finger for FSBP (all P>0.05). The average F_i of the study subjects was (98.0±16.6)%, with males and females having the average F_i of (100.7±20.7) % and (95.2±10.6) % respectively. The results of factorial analysis of variance showed that there was no significant difference on F_i in the main effect gender and fingers or the interaction effect between them(all P>0.05). Conclusion The FSBP test could be used as a detection method for assessing peripheral microcirculation function in Chinese population. However, further research is needed to establish reference ranges and influencing factors.

Objective:To investigate the effects of breast milk to total milk intake ratio during hospitalization on the duration of antibiotic therapy in preterm infants less than 34 weeks of gestation.Methods:Clinical data of preterm infants ( n=1 792) less than 34 gestational weeks were retrospectively collected in 16 hospitals of Jiangsu Province Neonatal-Perinatal Cooperation Network from January 1, 2019, to December 31, 2021. The days of therapy (DOT) were used to evaluate the duration of antibiotic administration. The median DOT was 15.0 d (7.0-27.0 d). The patients were divided into four groups based on the quartiles of DOT: Q 1 (DOT≤7.0 d), Q 2 (7.0 d27.0 d) groups. According to the breast milk intake ratio (breast milk intake to total milk intake during hospitalization×100%), they were also divided into four groups: very-low-ratio breastfeeding group (breast milk intake ratio≤25%), low-ratio breastfeeding group (25%75%). Univariate analysis ( Chi-square test and Kruskal-Wallis rank-sum test) was used to analyze the factors influencing DOT. Spearman correlation analysis and trend Chi-square test were used to explore the relationship between breast milk intake ratio and DOT. After using multiple imputations to address missing data, two models were constructed after adjusting for different factors, and multinomial logistic regression model was applied to evaluate the effects of the breast milk intake ratio on DOT. Finally, sensitivity analysis was conducted to assess the stability of the models. Results:(1) Of the 1 792 preterm infants, there were 507 (28.3%) in the Q 1 group, 422 (23.5%) in the Q 2 group, 438 (24.4%) in the Q 3 group and 425 (23.7%) in the Q 4 group. (2) The median values of DOT in the very-low-ratio, low-ratio, medium-ratio and high-ratio breastfeeding groups were 20.0 d (11.0-31.0 d), 20.0 d (11.0-32.0 d), 13.0 d (6.0-25.8 d) and 10.0 d (4.0-21.0 d), respectively. Compared with the very-low-ratio and low-ratio breastfeeding groups, the medium-ratio and high-ratio breastfeeding groups had shorter DOT (all P<0.05). (3) After adjusting for factors with P<0.1 (prenatal glucocorticoid exposure, antimicrobial use within 24 h before delivery, gestational age at delivery, birth weight, Apgar score≤7 at 1 min, neonatal respiratory distress syndrome, infectious pneumonia and early-onset neonatal sepsis) between the DOT quartile groups, it showed that medium-ratio and high-ratio breastfeeding were protective factors in contrast to very-low-ratio breastfeeding in the Q 2, Q 3 and Q 4 groups as compared with the Q 1 group [Q 2 group: OR=0.50 (95% CI: 0.30-0.85) and OR=0.36 (95% CI: 0.26-0.51); Q 3 group: OR=0.31 (95% CI: 0.18-0.55) and OR=0.20 (95% CI: 0.14-0.29); Q 4 group: OR=0.22 (95% CI: 0.12-0.42) and OR=0.17 (95% CI: 0.12-0.26)]. Conclusion:Breast milk intake accounting for over 50% of total milk intake has a positive impact on reducing DOT in premature infants requiring antibiotics, which suggests that breastfeeding should be actively encouraged.

Mesenchymal stem cells (MSCs) are capable of self-replication and multi-directional differentiation, which are very important for the development and reconstruction of mesenchymal tissue. Bone tissue damage repair involves the participation of various cells and molecules. The recovery of bone mass requires sufficiently many MSCs to migrate to the damaged site to perform the reconstruction function. The local inflammatory response at the injury site can recruit MSCs and promote new bone formation. Simultaneously, niche changes during the migration of MSCs will affect their biological performance and initiate the phase of directed differentiation. This article explores the relevant mechanisms that mediate the migration of MSCs in the process of bone injury repair, including the regulation of immune cells and chemotactic signaling molecules in the inflammatory response in the bone repair stage through signaling pathways such as BMP/Smads. Then, it summarizes the mechanism by which the high matrix stiffness upregulates the expression of the integrin and focal adhesions to promote the MSCs migration and osteogenic differentiation. Simultaneously, the migration ability of MSCs can be regulated through drugs or genetic modification to promote the bone injury repair. The improvement of MSCs migration ability can shorten the time of bone tissue damage repair and improve the bone quality. This article reviews the role of the MSCs migration ability in bone tissue injury repair to provide a reference for the application of MSCs with high migration ability in the fields of stem cell therapy for bone related diseases and bone tissue engineering.

OBJECTIVE: To analyze the effects of long term exposure to power frequency electromagnetic fields( PFEMF) on apoptotic rates of peripheral blood T and B lymphocytes in workers of transformer substation. METHODS: A random number table method was used to select 73 workers with long-term exposure to PFEMF as exposure group and 70 non-exposure workers( administrative and logistics staffs) were selected as control group from 10 transformer substations in a province.The peripheral venous blood of workers in these two groups was collected,and the apoptosis of T and B lymphocytes were detected and analyzed by flow cytometry. RESULTS: The apoptosis rates of T and B lymphocyte between the exposure and non-exposure groups showed no statistical difference( median: 1. 555% vs 0. 790%,0. 020% vs 0. 030%,P > 0. 05).The multivariate linear regression analysis showed that both the PFEMF exposure and length of service had no significant effects on the apoptosis rates of T lymphocyte and B lymphocyte after adjusting confounding factors such as gender,age,alcohol drinking,smoking,medication history,medical radiation exposure and stressful events( P > 0. 05). CONCLUSION: Long-term exposure to PFEMF has no effects on apoptosis of peripheral blood T and B lymphocytes in workers of transformer substation.