Objective To investigate the impact of ultra-high-frequency radiation(UHFR) on the mental arithmetic ability in exposed workers. Methods A total of 79 workers engaged in high-frequency heat-sealing operations in a shoe factory were selected as the exposure group, and 121 workers from the same factory without such exposure were selected as the control group using the judgment sampling method. The intensity of UHFR from the high-frequency heat-sealing machines at the workplaces was measured on-site. Mental arithmetic performance of the participants of the two groups was assessed using the neurobehavioral ability index (NAI) from Neurobehavioral Evaluation System Chinese 3rd Generation. Results The NAI of the participants was lower in the exposure group than that in the control group [(1.17 ± 0.48) vs (1.39 ± 0.59), P<0.01], as was the NAI of the high-exposure subgroup within the exposure group [ (1.10 ± 0.43) vs (1.39 ± 0.59), P<0.01]. Females in the exposed group had lower NAI than that in the control group [(1.14 ± 0.49) vs (1.39 ± 0.60), P<0.01]. Multivariable logistic regression analysis indicated that exposure to high intensity electric field was a risk factor for abnormal NAI (odds ratio=2.04, 95% confidence interval was 1.00-4.19, P<0.05). Conclusion Occupational exposure to UHFR from high-frequency heat-sealing machines may negatively affect the mental arithmetic ability of workers. Occupational health protection measures, such as reducing UHFR exposure levels, enhancing individual protection, and strengthening occupational health surveillance, should be implemented.

Background Although hand-arm vibration syndrome has traditionally been reported more frequently in colder northern regions, recent cases in Guangdong Province, a subtropical region in the south, exhibit a certain degree of clustering in terms of industry distribution and company size, and for a period of time, they account for a high proportion of the total number of cases reported nationwide. Objective To describe the occupational exposure profile of hand-transmitted vibration (HTV) in Guangdong Province in 2025 and to compare exposure levels across industries, enterprise sizes, and occupational categories. Methods Data were sourced from the Guangdong Provincial Occupational Health Quality Control Platform, to which occupational health technical service institutions across Guangdong Province submitted relevant reports in 2025. The dataset included employers with documented HTV hazards, measurement results, and the number of exposed workers. Exposure levels were categorized into four grades according to the 4-h energy-equivalent frequency-weighted vibration acceleration: Grade I (<1 m·s⁻²), Grade II (1-2.5 m·s⁻²), Grade III (>2.5-5 m·s⁻²), and Grade IV (>5 m·s⁻²). Results A total of 12468 employers with identifiable HTV exposure were identified through the platform in 2025, of which 11710 (93.92%) were in the manufacturing sector. By enterprise scale, 274 (2.20%) were large, 934 (7.49%) were medium-sized, 8 749 (70.17%) were small, and 2511 (20.14%) were micro-sized enterprises, with small enterprises accounting for the largest proportion. Among 22298 job posts with identified HTV exposure, grinding, assembly, polishing, burnishing, and welding were the most common tasks. The M (P₂₅, P₇₅) 4-h energy-equivalent frequency-weighted acceleration [a(4)] was 2.1 (1.5, 2.7) m·s⁻², with values ranging from 0.1 to 16.2 m·s⁻². Exposure levels were distributed as follows: Grade I, 2835 posts (12.71%); Grade II, 12761 posts, (57.23%); Grade III, 6690 posts, (30.00%); and Grade IV, 12 posts (0.05%), with Grade Ⅱ posts accounting for the largest proportion. Within the manufacturing sector, 21013 exposed job posts were identified, accounting for 94.24% of all exposed posts. Twelve job posts exceeded the occupational exposure limit, of which nine were polishing positions. A total of 115955 workers were exposed to HTV, primarily in manufacturing (110879; 95.62%). Among the exposed workers, 21237, 23454, 65047, and 6217 were employed in large, medium, small, and micro-sized enterprises, respectively. Grinding, assembly, polishing, deburring, and welding were the five most common occupational categories among the exposed workers. The distribution of worker by exposure grade was similar to that of exposed posts: Grade I, 11921 workers (10.28%); Grade II, 65463 workers (56.46%); Grade III, 38447 workers (33.16%); and Grade IV, 124 workers (0.11%). Conclusion In Guangdong Province, HTV exposure is mainly concentrated in the manufacturing sector, particularly in metal product manufacturing, and commonly involves tasks such as grinding, assembly, and polishing. Both exposed enterprises and exposed workers are predominantly concentrated in small enterprises. Grade II exposure accounts for the largest proportion of both exposed job posts and exposed workers, and some workers are at a risk of developing hand-arm vibration syndrome. These findings suggest that targeted occupational management and comprehensive control measures should be strengthened to reduce HTV exposure and prevent hand-arm vibration syndrome.

Objective: To investigate the distribution of pupil diameter and its association with myopia in school age children, providing ideas into the mechanisms of the role of pupil diameter in the onset and development of myopia. Methods: Adopting a combination of stratified cluster random sampling and convenience sampling method, 3 839 children from six schools in Shandong Province were included in September 2021. Pupil diameters distribution was analyzed by age, sex, and myopic status. Pearson correlation analysis was used to assess the relationship between pupil diameter and cycloplegic spherical equivalent (SE), as well as axial length (AL) and other variables. Propensity score matching (PSM) was applied to match myopic and non myopic children at a 1∶1 ratio based on age and sex. A generalized linear model (GLM) was constructed with pupil diameter as the dependent variable to identify independent factors influencing pupil size and its association with myopia. Results: The mean pupil diameter of school age children was (5.77±0.80)mm. Pupil diameter exhibited a significant increasing trend with age ( F =49.34， P trend ＜ 0.01). Myopic children had a significantly larger mean pupil diameter [(6.10±0.73)mm] compared to non myopic children [(5.62±0.79)mm] with a statistically significant difference( t=18.10, P <0.01). Multivariable GLM analysis, adjusted for age, amplitude of accommodation, and uncorrected visual acuity, revealed a negative correlation between pupil diameter and cycloplegic SE (before PSM: β =-0.089, after PSM: β =-0.063, both P ＜0.01). Conclusions Myopic school age children exhibite larger pupil diameters than their non myopic counterparts. Pupil diameter may serve as a potential indicator for monitoring myopia development in school age children.

Objective To investigate the prevalence and risk factors of work-related musculoskeletal disorders (WMSDs) among construction workers. Methods A total of 5 783 workers were selected as participants from 12 construction companies in Guangdong Province, Guangxi Zhuang Autonomous Region and Zhejiang Province using a convenient sampling method. The revised Musculoskeletal Disorders Questionnaire was used to investigate the prevalence and influencing factors of WMSDs. Results The prevalence of WMSDs was 27.4% among the construction workers. The prevalence of WMSDs in shoulder, neck, waist/lower back and hand/wrist was 10.6%, 9.5%, 9.5% and 9.4% respectively, which was higher than that in other body parts. Bianry logistic regression analysis showed that the risk of WMSDs in construction workers with junior high school education and below was higher than that of high school/ college and above (P<0.05). The risk of WMSDs was higher in drinkers than that in non-drinkers (P<0.01). The worse the health status of construction workers, the higher the risk of WMSDs (P<0.01). The risk of WMSDs in those who exercised once or twice a month was lower than that in those who did not exercise (P<0.05). The risk of WMSDs was higher in construction workers with longer working hours in uncomfortable postures and greater back bending amplitude at work (all P<0.01). The risk of WMSDs in construction workers with hands holding above the shoulder was higher than that with hands below the shoulder (P<0.05). Construction workers who repeated the same work daily, involved in high-temperature work, often worked overtime, had insufficient rest time, and had a shortage of department personnel had a relatively high risk of WMSDs (all P<0.01). Conclusion The prevalence of WMSDs among the construction workers was relatively high, and the most common WMSDs occurred in shoulder, neck, waist/lower back and hand/wrist. Individual characteristic, work type, work posture and work organization are the influencing factors of WMSDs. Comprehensive measures, especially ergonomic measures based on personal and occupational characteristics should be taken to reduce the risk of WMSDs among construction workers.

Objective To analyze the effect of hand transmitted vibration on fingertip thermotactile perception threshold (TPT) among grinding workers in a sports equipment manufacturing enterprise. Methods A total of 151 male grinding workers from a sports equipment manufacturing enterprise in Guangdong Province were enrolled in the vibration exposure group, and 51 male workers without hand-transmitted vibration exposure were enrolled in the control group, using the judgment sampling method. Basic health conditions of the workers were surveyed in both groups. The TPTs of the distal phalanges of the index and little fingers on both hands were tested using an HVLab thermal perception tester. Results The detection rates of finger numbness and tingling among workers in the vibration exposure group were higher than those in the control group (92.1% vs 7.8% and 59.6% vs 0.0%, respectively, both P<0.01). The detection rates of numbness or tingling of different fingers in the vibration exposure group descended in the following order: index finger, middle finger, ring finger, thumb and little finger. The hot threshold of the index finger and little finger increased (all P<0.01), while the cold threshold decreased (all P<0.01) in the vibration exposure group, compared with the control group. The results of generalized linear regression analysis showed that with the increase of the duration of hand-transmitted vibration, the hot threshold of the index finger and the little finger of both hands increased (all P<0.01), and the cold threshold decreased (all P<0.01). The hot thresholds of workers with numbness of both the index fingers and left little finger were higher than those of workers without numbness of the same finger (all P<0.05). The hot threshold of workers with tingling of the left index finger was higher than those without tingling (P<0.05). The cold thresholds of workers with tingling of the both index fingers and left little finger were lower than those without tingling of the same finger (all P<0.05). The hot threshold of the right little finger increased with age (P<0.01), while the cold thresholds of both little fingers decreased with age (all P<0.01). Conclusion Hand-transmitted vibration exposure increases fingertip hot threshold and decreases fingertip cold threshold of workers exposed to hand-transmitted vibration. Years of service in hand-transmitted vibration work, finger numbness or tingling, and age were influencing factors of TPT. Fingertip TPT examination can be used to assist in the early detection of vibration-induced nerve injury in workers exposed to hand-transmitted vibration.

Objective To understand the characteristics of occupational noise hazards in key industries in Huizhou City. Methods A total of 247 enterprises from 13 key industries in Huizhou City were selected as the research subjects using the stratified judgment sampling method. The worksite survey of occupational health and workplace noise intensity and spectrum monitoring were conducted at key work sites using "questionnaires and on-site inspections" method. Results The rate of noise intensity exceeding national standards was 53.4% (132/247). The median, 25th and 75th percentile of noise pressure levels in workplaces and worksites were 85.1 (81.2, 91.2)and 82.5 (78.8, 86.3) dB(A), respectively. The high-noise workplaces accounted for 50.0% (479/958). The rate of noise intensity exceeding national standard at work sites was 32.9% (303/921). The sound pressure level of noise at work sites was positively correlated with sound pressure level of noise sources (Spearman correlation coefficient=0.73, P<0.01). The top three high-risk work sites for exceeding national noise standards were grinding, frame nailing, and material cutting, with exceedance rates of 84.6%, 81.3%, and 62.8%, respectively. The frequency characteristics of the top ten high-risk work sites were mainly high-frequency noise. There were significant differences in noise spectrum characteristics among different workpiece materials used in similar types of work sites (all P<0.05), though high-frequency noise remained dominant. Conclusion Noise hazards in workplaces of key industries in Huizhou City are relatively severe. Continuous attention should be given to key work sites with high over-standard rate, such as grinding, frame nailing, and material cutting, and noise control strategies should be developed based on frequency spectrum characteristics.

At present, the C-arm structure accelerators commonly used in radiotherapy equipment are complex in operation and have potential safety hazards when realizing non-coplanar treatment. By combining with medical robotic arm technology, a spherical radiotherapy accelerator motion system is designed. The beam module is clamped by the medical robotic arm structure to achieve three-dimensional multi-angle irradiation treatment within the non-coplanar angle range. Firstly, the rotating mechanism, beam module, and MLC module of the spherical radiotherapy equipment are designed. Then, the double-plane counterweight method is used to calculate the dynamic balance of the equipment, ensuring that the beam center point does not rotate during the treatment process. Finally, the strength check and reliability analysis of the transmission component gear are conducted. The results show that the designed spherical radiotherapy accelerator motion system can meet the requirements of stable, accurate, and fast precision radiotherapy, which is conducive to improving the treatment efficiency.
Particle Accelerators/instrumentation* ; Equipment Design ; Reproducibility of Results ; Radiotherapy/instrumentation*

Objective To evaluate the role of distortion product otoacoustic emissions (DPOAE) testing in evaluating early hearing loss among noise-exposed workers. Methods A total of 174 noise-exposed workers in a metal shipbuilding enterprise were selected as the research subjects by the convenience sampling method. Pure tone audiometry (PTA), DPOAE and the level of noise exposure were conducted on the workers. The rank correlation analysis was used to analyze the correlation between DPOAE amplitude and PTA threshold. The multilevel model was used to analyze the effects of gender, age, noise exposure intensity, cumulative noise exposure (CNE), hearing loss classification and PTA threshold on DPOAE results. Results At the frequencies of 0.50, 1.00, 2.00, 3.00, 4.00, 6.00 and 8.00 kHz, the DPOAE amplitude was negatively correlated with the PTA threshold (rank correlation coefficients were -0.12, -0.48, -0.47, -0.18, -0.23, -0.44, -0.19, respectively, all P<0.01). At the most frequencies, DPOAE amplitude was negatively correlated with age and CNE (all P<0.05). The results of multilevel model analysis showed that there were significant differences in DPOAE amplitudes at certain frequencies across gender, age, noise intensity, CNE, and hearing loss classification (all P<0.05). Significant differences in DPOAE responses were found among different CNE and hearing loss groups (all P<0.01). Conclusion DPOAE testing can objectively reflect the hearing status of noise-exposed workers and could be considered for inclusion in routine hearing monitoring to facilitate early detection of noise-induced hearing loss.

Objective:To analyze the correlation between near work, screen time, outdoor time and myopia in children based on objective monitoring technology and to explore the influencing factors related to myopia in children.Methods:A cross-sectional study was conducted.From October 2022 to March 2023, the purposive sampling method was used to select 596 children in Grade 2 and Grade 3 from two primary schools in Shandong Province as study subjects.Eye-Monitor technology of eye-use behavior based on artificial intelligence was used to quantify parameters of near work, screen time and outdoor time.The eye-use behavior parameters were compared within each subject and between non-myopic and myopic children on weekdays and weekends.A multivariate binary logistic regression model was constructed to analyze the influencing factors related to myopia.The study protocol was approved by the Medical Ethics Committee of the Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine (No.HEC-HY-2022023KY).Written informed consent was obtained from the legal guardian of each subject.Results:For each subject, the proportion of near work time on weekdays was greater than on weekends, the proportion of time spent looking at cell phones, computer screens, and outdoor activities was smaller, the duration of single continuous near eye use was longer, the tilt angle of the head in sitting position was greater, and the light intensity was stronger, showing statistically significant differences ( t=19.427, -9.964, -5.916, -10.470, 2.211, 2.898, 15.061; all P<0.05).During weekdays, compared with the non-myopia group, the myopia group had longer total near work duration, longer single continuous near eye use duration, shorter outdoor activity duration, closer eye use distance, larger proportion of near work time, and smaller proportion of outdoor activity time, showing statistically significant differences (all P<0.05).During weekends, compared with the non-myopia group, the myopia group had longer time spent looking at cell phones and computer screens, shorter outdoor activity time, greater proportion of time spent looking at cell phones and computer screens, and smaller proportion of outdoor activity time, with statistically significant differences (all P<0.05).During weekdays, after adjusting for confounding factors, longer single continuous near eye use duration ( OR=1.138, 95% CI: 1.086-1.192, P<0.001) was the risk factor for myopia, and longer working distance ( OR=0.906, 95% CI: 0.847-0.970, P=0.004) and longer outdoor activity time ( OR=0.127, 95% CI: 0.023-0.703, P=0.018) were protective factors for myopia.During weekends, after adjusting for confounding factors, longer time spent on looking at cell phone screens ( OR=2.437, 95% CI: 1.460-4.068, P<0.001) and longer time spent on looking at computer screens ( OR=2.260, 95% CI: 1.283-3.979, P=0.005) were risk factors for myopia, and longer outdoor activity time ( OR=0.624, 95% CI: 0.416-0.934, P=0.022) was the protective factor for myopia. Conclusions:The eyes with continuous near work, prolonged use of smartphone and computer screens, closer eye use distance, and less time spent outdoors have been confirmed to be significantly correlated with myopia based on objective monitoring data.When formulating intervention measures for myopia prevention and control in children, it is advocated to further pay attention to control the distance and duration of near work on weekdays and strengthen screen time management on weekends.

Objective:To analyze the correlation between near work, screen time, outdoor time and myopia in children based on objective monitoring technology and to explore the influencing factors related to myopia in children.Methods:A cross-sectional study was conducted.From October 2022 to March 2023, the purposive sampling method was used to select 596 children in Grade 2 and Grade 3 from two primary schools in Shandong Province as study subjects.Eye-Monitor technology of eye-use behavior based on artificial intelligence was used to quantify parameters of near work, screen time and outdoor time.The eye-use behavior parameters were compared within each subject and between non-myopic and myopic children on weekdays and weekends.A multivariate binary logistic regression model was constructed to analyze the influencing factors related to myopia.The study protocol was approved by the Medical Ethics Committee of the Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine (No.HEC-HY-2022023KY).Written informed consent was obtained from the legal guardian of each subject.Results:For each subject, the proportion of near work time on weekdays was greater than on weekends, the proportion of time spent looking at cell phones, computer screens, and outdoor activities was smaller, the duration of single continuous near eye use was longer, the tilt angle of the head in sitting position was greater, and the light intensity was stronger, showing statistically significant differences ( t=19.427, -9.964, -5.916, -10.470, 2.211, 2.898, 15.061; all P<0.05).During weekdays, compared with the non-myopia group, the myopia group had longer total near work duration, longer single continuous near eye use duration, shorter outdoor activity duration, closer eye use distance, larger proportion of near work time, and smaller proportion of outdoor activity time, showing statistically significant differences (all P<0.05).During weekends, compared with the non-myopia group, the myopia group had longer time spent looking at cell phones and computer screens, shorter outdoor activity time, greater proportion of time spent looking at cell phones and computer screens, and smaller proportion of outdoor activity time, with statistically significant differences (all P<0.05).During weekdays, after adjusting for confounding factors, longer single continuous near eye use duration ( OR=1.138, 95% CI: 1.086-1.192, P<0.001) was the risk factor for myopia, and longer working distance ( OR=0.906, 95% CI: 0.847-0.970, P=0.004) and longer outdoor activity time ( OR=0.127, 95% CI: 0.023-0.703, P=0.018) were protective factors for myopia.During weekends, after adjusting for confounding factors, longer time spent on looking at cell phone screens ( OR=2.437, 95% CI: 1.460-4.068, P<0.001) and longer time spent on looking at computer screens ( OR=2.260, 95% CI: 1.283-3.979, P=0.005) were risk factors for myopia, and longer outdoor activity time ( OR=0.624, 95% CI: 0.416-0.934, P=0.022) was the protective factor for myopia. Conclusions:The eyes with continuous near work, prolonged use of smartphone and computer screens, closer eye use distance, and less time spent outdoors have been confirmed to be significantly correlated with myopia based on objective monitoring data.When formulating intervention measures for myopia prevention and control in children, it is advocated to further pay attention to control the distance and duration of near work on weekdays and strengthen screen time management on weekends.