Objective To search for a procedure for correction of square face. Methods 68 patients with square face (aged from 21～40 years, with 65 females and 3 males) underwent osteetomy combined mandibular angle triangle resection with lateral cortex around the mandibular angle-splitting by intraoral approach. The mandible outer cortex was splited with bone chisel and mandible angle was resected by the high-speed pneumatic drill. The bulky masseter muscle and the enbonpoint buecal fat-pad were scissored. Results The application of high-speed pneumatic drill and bone chisel facilitated resection of the mandibular angle with lateral cortex splitting osteetomy. The operative effects were satisfactory in 56 patients during 3-24 months of follow-up. The bigonial distance was effectively re-duced, and facial shape became ellipse. The gross asymmetry and mandibular fracture were not conse-quences. The lateral contour of the mandibular angle was natural. Conclusion Ostectomy of mandible angle and lateral cortex of the mandible allows the reduction of the mandibular contour of the frontal view and the lateral contour of mandibular angle becomes soft, giving a more natural appearance. This new method is worthy to be applied widely because of the good result with effective reduction of the mandibular width.

Objective To evaluate the clinical application of endoscopic technique in corrections of square face. Methods A total of 38 patients (age 21~40 years, 35 women and 3 men) with square face were corrected by endoscope-assisted intraoral approach and resected mandibular angle with the high-speed pneumatic drill or bulky masseter muscle and buccal fat pad. Results The use of an endoscope offered a clear view of the mandibular angle region and the application of high-speed pneumatic drill facilitated accurate and easy resection of the the mandibular angle. These patients were successfully treated for these new techniques: ruduced surgical trauma, operative bleeding and surgical time, along with a reduced risk of infection. Conclusion The endoscopic assisted correction of square face offers more satisfactory clinical results with a clear view of operation and less haematoma, risk of infection, surgical trauma and time.

Objective To investigate the occupational health status of the radiation workers in Xiamen, China, and provide direction and basis for improvement of occupational health surveillance. Methods After excluding duplicate records, a total of 7000 individuals who underwent occupational health examinations due to radiation exposure in Xiamen City from 2022 to 2023 were selected. Among them, 2499 individuals underwent examinations before employment, 4090 during employment, and 411 at the time of job separation. The results were analyzed. Results A total of 6979 (99.7%) individuals were deemed fit to engage (or continue engaging) in radiation work or to leave the position, while 21 (0.3%) individuals were found unfit. In the routine medical examinations of different genders, the items with relatively high abnormal rates included overweight and obesity (35.22%, χ² = 43.29, P < 0.01), abnormal liver function (33.74%, χ² = 153.53, P < 0.01), abnormal renal function (25.83%, χ² = 195.22, P < 0.01), and hyperuricemia (24.53%, χ² = 267.78, P < 0.01). For all of these items, the abnormality rates were significantly higher in males than in females. The abnormal rates of examination items related to radiation hazard factors were generally higher for females than for males. Statistically significant gender differences were observed in lens abnormality rate (χ² = 11.38, P < 0.001), the decrease rate of white blood cells (χ² = 12.04, P < 0.001), the abnormal rate of red blood cells (χ² = 25.47, P < 0.01), the abnormal rate of platelets (χ² = 88.07, P < 0.01), and the micronucleus rate of peripheral blood lymphocytes (χ² = 6.98，P = 0.008). The difference in micronucleus rate of peripheral blood lymphocytes among groups with different years of radiation exposure was statistically significant, and the rate increased with increasing exposure years. Conclusion Long-term exposure to radiation has a certain impact on the health of radiation workers. Radiation workers should enhance radiation protection measures, increase the awareness of protection, and reduce radiation-related damage.

Objective To investigate the occupational health status of the radiation workers in Xiamen, China, and provide direction and basis for improvement of occupational health surveillance. Methods After excluding duplicate records, a total of 7000 individuals who underwent occupational health examinations due to radiation exposure in Xiamen City from 2022 to 2023 were selected. Among them, 2499 individuals underwent examinations before employment, 4090 during employment, and 411 at the time of job separation. The results were analyzed. Results A total of 6979 (99.7%) individuals were deemed fit to engage (or continue engaging) in radiation work or to leave the position, while 21 (0.3%) individuals were found unfit. In the routine medical examinations of different genders, the items with relatively high abnormal rates included overweight and obesity (35.22%, χ² = 43.29, P < 0.01), abnormal liver function (33.74%, χ² = 153.53, P < 0.01), abnormal renal function (25.83%, χ² = 195.22, P < 0.01), and hyperuricemia (24.53%, χ² = 267.78, P < 0.01). For all of these items, the abnormality rates were significantly higher in males than in females. The abnormal rates of examination items related to radiation hazard factors were generally higher for females than for males. Statistically significant gender differences were observed in lens abnormality rate (χ² = 11.38, P < 0.001), the decrease rate of white blood cells (χ² = 12.04, P < 0.001), the abnormal rate of red blood cells (χ² = 25.47, P < 0.01), the abnormal rate of platelets (χ² = 88.07, P < 0.01), and the micronucleus rate of peripheral blood lymphocytes (χ² = 6.98，P = 0.008). The difference in micronucleus rate of peripheral blood lymphocytes among groups with different years of radiation exposure was statistically significant, and the rate increased with increasing exposure years. Conclusion Long-term exposure to radiation has a certain impact on the health of radiation workers. Radiation workers should enhance radiation protection measures, increase the awareness of protection, and reduce radiation-related damage.

Objective To investigate the occupational health status of the radiation workers in Xiamen, China, and provide direction and basis for improvement of occupational health surveillance. Methods After excluding duplicate records, a total of 7000 individuals who underwent occupational health examinations due to radiation exposure in Xiamen City from 2022 to 2023 were selected. Among them, 2499 individuals underwent examinations before employment, 4090 during employment, and 411 at the time of job separation. The results were analyzed. Results A total of 6979 (99.7%) individuals were deemed fit to engage (or continue engaging) in radiation work or to leave the position, while 21 (0.3%) individuals were found unfit. In the routine medical examinations of different genders, the items with relatively high abnormal rates included overweight and obesity (35.22%, χ² = 43.29, P < 0.01), abnormal liver function (33.74%, χ² = 153.53, P < 0.01), abnormal renal function (25.83%, χ² = 195.22, P < 0.01), and hyperuricemia (24.53%, χ² = 267.78, P < 0.01). For all of these items, the abnormality rates were significantly higher in males than in females. The abnormal rates of examination items related to radiation hazard factors were generally higher for females than for males. Statistically significant gender differences were observed in lens abnormality rate (χ² = 11.38, P < 0.001), the decrease rate of white blood cells (χ² = 12.04, P < 0.001), the abnormal rate of red blood cells (χ² = 25.47, P < 0.01), the abnormal rate of platelets (χ² = 88.07, P < 0.01), and the micronucleus rate of peripheral blood lymphocytes (χ² = 6.98，P = 0.008). The difference in micronucleus rate of peripheral blood lymphocytes among groups with different years of radiation exposure was statistically significant, and the rate increased with increasing exposure years. Conclusion Long-term exposure to radiation has a certain impact on the health of radiation workers. Radiation workers should enhance radiation protection measures, increase the awareness of protection, and reduce radiation-related damage.

Background Air pollution exposure has a significant impact on maternal and child health. However, the research on the association between ambient ozone (O₃) exposure during pregnancy and the risk of premature birth in newborns is limited, and the conclusions are inconsistent. Objective To investigate the association of ambient O₃ exposure during pregnancy with the risk of preterm birth in Guangdong Province. Methods Data of pregnant women in Guangzhou from 2013 to 2019 and Foshan from 2018 to 2023 were collected, and O₃ concentrations during different trimesters were assessed according to maternal residential addresses. Bilinear interpolation was used to evaluate the concentrations of air pollution. A cohort study design was adopted in our study. Restricted cubic spline curves were used to evaluate the exposure-response relationship between O₃ exposure and preterm birth risk and explore potential exposure threshold of O₃. Logistic regression models were used to evaluate the association of O₃ exposure with preterm birth. Results A total of 702 924 pregnant women were included in this study, of whom 43 051 (6.12%) were preterm. The average O₃ exposure concentrations of pregnant women during the first, second, third, and whole trimesters were 95.51, 97.51, 100.60, and 97.87 μg·m⁻³, respectively. We observed J-shaped associations between O₃ exposure and preterm birth risk during the second, third, and whole trimesters of pregnancy using restricted cubic spline curves. This study found that there were threshold concentrations between O₃ exposure and preterm birth risk during different gestational periods, and the threshold concentrations in the first, second, third, and whole trimesters were 112.32, 99.83, 111.74, and 112.46 μg·m⁻³, respectively. During the second, third, and whole trimesters of pregnancy, after adjusting for maternal age, baby sex, pre-pregnancy body mass index, mode of delivery, baby birth weight, gestational diabetes, and gestational hypertension, the odds ratios (OR) of preterm birth were 1.02 (95%CI: 1.01, 1.04), 1.02 (95%CI: 1.00, 1.03), and 1.17 (95%CI: 1.13, 1.21) for each 10 μg·m⁻³ increase in O₃ concentration above the O₃ threshold. No significant association was found between O₃ exposure and the risk of preterm birth during the first trimester. Conclusion There is a nonlinear association between the risk of preterm birth and O₃ exposure during pregnancy, and higher concentrations of O₃ exposure during pregnancy are associated with the risk of preterm birth. Above the O₃ threshold concentration during pregnancy, especially during the second, third, and whole trimesters, the risk of preterm birth elevates with the increase of O₃ exposure concentrations.