Objective To analyze the distribution characteristics of the single nucleotide polymorphism (SNP) site rs76206423 in the promoter region of the interleukin-2 receptor (IL-2R) β gene among Han males in a high radiation background area (HBRA) in Yangjiang City. Methods A total of 48 male participants from Tangkou Town, Yangxi County, Yangjiang City (HBRA group), and 51 male participants from Hengpo Town, Enping City (control group) were selected as the research subjects using the random number table method. Peripheral venous blood samples of participants from both groups were collected, and genomic DNA was extracted. The genotyping and allele frequency distribution of the rs76206423 (A/G) site in the IL-2R β promoter region was detected among the participants in both groups using the SNP detection method. The difference of allele frequencies between population in HBRA group and five area of East Asia, South Asia, Africa, Europe, and the Americas published in the Human Genome Project database from National Center for Biotechnology Information were analyzed. Results The allele frequencies of rs76206423 of population in both groups conformed to Hardy-Weinberg equilibrium (P>0.05). In the HBRA group, the AA genotype was predominant (64.6%), while the AG genotype was the most common in the control group (51.0%), with a significant difference (P<0.05). Population in both groups showed a predominance of the variant allele A (78.1% and 72.5%, respectively), with no significant difference (P>0.05). The frequency of the G allele of rs76206423 in the population in HBRA group was higher than those in South Asian, African, European, and American populations (all P<0.01), but showed no significant difference compared with East Asian populations (P>0.05). Conclusion In the Han male population from the HBRA in Yangjiang City, the rs76206423 site in the IL-2R β gene promoter region is predominantly composed of the wild-type A allele and AA genotype, indicating genetic stability and a relatively high degree of variation at this locus.

Objective To analyze the monitoring status of occupational hazard factors in key industry workplaces in a city of the Pearl River Delta area from 2019 to 2023. Methods A total of 1 548 enterprises in 12 key industries of the city were selected as the research subjects using the judgmental sampling method. Their monitoring data for dust, chemical factors, and noise, along with the occupational health management status of the enterprises were analyzed. Results Among the 1 548 enterprises, large and medium-sized enterprises accounted for 2.7% and 13.4%, while small and micro enterprises accounted for 83.9%. A total of 474 enterprises exceeded the national limit in the detection of occupational hazard factors, with an exceedance rate of 30.6%. The rates of workers exposed to occupational hazard factors, dust, chemical factors, and noise were 29.4%, 6.9%, 21.0%, and 13.0%, respectively, all showing a downward trend year by year (all P<0.05). The training rates for occupational health among enterprise managers, responsible persons, and workers were 84.1%, 84.2%, and 91.2%, respectively. The detection rates for abnormal occupational health examinations among workers exposed to dust, chemical factors, and noise were 0.2%, 0.3%, and 0.5%, respectively. The setting rates of warning signs and warning instructions among enterprises for dust, chemical toxins, and noise were 87.3%, 91.1%, and 89.5%, respectively. The setting rates for dust, toxic chemical, and noise control facilities were 72.4%, 75.4%, and 46.0%, with effectiveness rates of 70.5%, 56.6%, and 55.2%, respectively. The distribution rates of personal protective dust masks, gas masks, and noise earplugs/earmuffs were 91.9%, 83.8%, and 86.4%, with wearing rates of 80.8%, 70.5%, and 76.4%, respectively. The detection rates of exceeding national limits for dust, chemical factors, and noise in the work site of occupational hazard factors were15.2%, 1.0%, and 21.6%, respectively. The detection rates of exceeding national limits for dust, chemical factors, and noise in the workplace of occupational hazard factors were 2.4%, 2.5%, and 12.3%, respectively. The exceedance rate for noise in work site showed an upward trend year by year (P<0.01). Conclusion Occupational disease prevention and control work in the key industries of this city needs strengthening. It is essential to further enhance the regular monitoring and preventive measures of occupational hazard factors in enterprises, improve protective measures, strengthen the use of personal protective equipment, and enhance occupational health training and supervision, to effectively reduce the risk of occupational diseases and protect workers' occupational health rights.

Objective To obtain the protective performance parameters of barium sulfate mortar against positron nuclide γ-rays, provide reference data for precise shielding calculations, and guide the design, evaluation, and construction of radiation shielding. Methods The FLUKA program was used to build a model for simulating the dose equivalent rate variation around points of interest under the irradiation of the most commonly used positron nuclide ¹⁸F with changes in the thicknesses of lead and barium sulfate mortar. The transmission curves of lead and barium sulfate mortar were fitted, and the half-value layer (HVL) and lead equivalence of barium sulfate mortar were calculated based on the fitted curves. Results The ambient dose equivalent rate coefficient of positron nuclide ¹⁸F was 1.339 4×10⁻¹ μSv·m²/MBq·h and the HVL for lead was 4.037 mm, with deviations of 0.043% and 1.53% compared to the values provided in the AAPM Report No. 108, respectively. The HVLs for γ-rays produced by ¹⁸F, using barium sulfate mortar with apparent densities of 4.20, 4.00, and 3.90 g/cm³ mixed with 35.2-grade cement in a 4∶1 mass ratio, were 2.914, 2.969, and 3.079 cm, respectively. The lead equivalences were 0.1385, 0.1360, and 0.1311 mmPb/mm, respectively. Conclusion The three types of barium sulfate mortar can provide good protection against γ-rays in positron imaging locations. As the apparent density of barium sulfate increases, its protective effect improves slightly but remains significantly better than common construction materials like concrete and solid bricks.

Acute Gelsemium poisoning is a systemic disease primarily affecting the central nervous system and respiratory symptoms caused by the ingestion of a substantial amount of Gelsemium within a short period. It manifests as sudden onset and rapid progression, primarily caused by accidental ingestion due to misidentification, and posing significant health risks. The compilation of the Technical Plan for Emergency Health Response to Acute Gelsemium Poisoning describes in detail the specialized practice and technical requirements in the process of handling acute Gelsemium poisoning, including accident investigation and management, laboratory testing and identification, in-hospital treatment, and health monitoring. The guidelines clarify key procedures and requirements such as personal protection, investigation elements, etiology determination, medical rescue, and health education. The key to acute Gelsemium poisoning investigation lies in promptly identifying the toxin through exposure history, clinical manifestations, and sample testing. Because there is no specific antidote for Gelsemium poisoning, immediate removal from exposure, rapid elimination of the toxin, and respiratory monitoring are critical on-site rescue measures. Visual identification of food or herbal materials, followed by laboratory testing to determine Gelsemium alkaloids in samples is a rapid effective screening method. These guidelines offer a scientific, objective, and practical framework to support effective emergency responses to acute Gelsemium poisoning incidences.

Objective To simulate and analyze the dose distribution from external exposure and its influencing factors of induced radioactivity in proton therapy site. Methods Referencing a domestically under-construction proton therapy facility, a geometric model of the proton therapy site was constructed, and the FLUKA program was used to simulate the distribution of the induced radioactive dose of the proton therapy site under the conditions of different energies, beam angles, irradiation time, cooling time and medium of the treatment site. Results For a 230 MeV proton beam with a current of 3.0 nA, directed along the negative Z-axis and irradiating a phantom for two minutes, at the shutdown moment, the ambient dose equivalent rates in air and vacuum 5, 30, and 50 cm away from the phantom surface were (1 039.02±5.82)-(127.86±1.20) and (1 037.96±4.38)~(127.35±0.93) μSv/h, respectively. The mean difference was 0.51~1.06 μSv/h, and the air-immersed external irradiation accounted for <1% of the total irradiation, which rapidly decreased to 1/15 of the shutdown moment value after cooling for 10 minutes. Under the condition of 130~250 MeV, the ambient dose equivalent rates at the shutdown moments 5, 30 and 50 cm away from the surface of the phantom were (427.49±3.12)-(1 058.41±4.66), (100.36±0.92)-(259.70±1.69) and (50.15±0.68)-(131.93±1.11) μSv/h, respectively. Irradiation for one-five minutes, and at the moment of shutdown at 5, 30, and 50 cm from the surface of the phantom were (688.19±3.33)-(1 594.04±8.08), (167.60±1.35)-(388.24±2.96) and (84.73±0.69)-(195.94±1.56) μSv/h. The peripheral dose-equivalent rate of the sensed radioactivity decreases with the irradiation time, the energy of the beam, and the distance from the model. The peak dose equivalent rate around the induced radioactivity exists in the beam direction, which is significantly larger than that in the non-beam direction. Conclusion Proton therapy sites are characterized by relatively large levels of induced peripheral radioactive dose equivalent rates, mainly originating from patients. In actual practice, a suitable working position can be chosen according to the direction of the beam current, especially the direction of the final irradiation field beam current, in the non-beam current direction and as far away from the patient as possible. Within 10 minutes after the end of treatment, staff should try to avoid close contact with the patients.

Respiratory protective equipment (RPE) is an effective measure to protect the health of workers. The domestic and foreign facial classfication of fit testing of RPE is mainly categorized into Los Alamos National Laboratory (LANL) classification, National Institute for Occupational Safety and Health (NIOSH) classification, principal component analysis (PCA) classification, Chinese Han adult facial classification, and Chinese young male facial classification. The LANL classification has low applicability. The NIOSH classification included different ethnicity and region of the study subjects, which is more representative for the American population. The PCA facial classification is complex to use and has low matching with RPE sizes. The Chinese Han adult facial classification and Chinese young male facial classification included more facial data of Chinese Han population and young population. There are qualitative and quantitative fit testing. Qualitative methods include the isoamyl acetate method, saccharin solution aerosol method, aerosol bitter testing solution method, and irritant smoke method which are cost-effective and easy to use, but are highly subjective to the study subjects. Quantitative methods include the aerosol generated method, environmental aerosol condensation nucleus counting method, and the controlled negative pressure method, which accurately quantify the facial fit of RPE but require specific testing equipment and high costs. It is necessary to include occupational populations from multiple industries, combine facial fit testing and fit testing methods of RPE, and establish a follow-up database based on digital information platforms, to achieve dynamic monitoring of respiratory protection levels among different occupational populations in the future.

The incidence of occupational injury accidents in the metallurgy and mechanical manufacturing industries remains high, posing risks not only to the safety and health of workers but also causing heavy economic burdens to enterprises and families. The occupational injury accidents in metallurgy and mechanical manufacturing industries were caused by the following six items： human factors, machine factors, building factors, raw material factors, environmental factors, and management factors. The types and body parts of occupational injury accidents varied among different industries due to the nature of the occupation and working environment. Occupational injury accidents were both sudden and preventable. Currently, comprehensive intervention measures for occupational injury accidents at China and abroad included safety education, improving work environments, optimizing building layout and facilities, and enhancing safety management capabilities. Effective and feasible intervention measures for occupational injury accidents should be based on the characteristics and causes of occupational injury accidents in each industry, and should include corresponding interventions for workers, machines, buildings, raw materials, environment, and management.

Noise is a common occupational hazard in workplaces. Long-term exposure to high-intensity noise mainly causes occupational noise-induced hearing loss (ONIHL). The development of ONIHL is irreversible, and there is currently no cure. At present, risk assessment methods based on noise exposure intensities mainly include risk index assessment method, Engineering Professional Council assessment method in United Kingdom (EDC assessment method in UK), National Institute of Occupational Safety and Health assessment method in United State (NIOSH assessment method in US), and International Standardization Organization assessment method (ISO assessment method). However, the risk index assessment method is subjective and does not consider the effectiveness of workers wearing protective equipment. The EDC assessment method in UK defines ONIHL differently from China. The NIOSH assessment method in US and ISO assessment methods have population data sources that deviate from China, which can lead to bias in risk assessment. In the future, it is necessary to further carry out application research on the risk assessment of ONIHL in Chinese noise-exposed workers, compare the applicabilities of various assessment methods, conduct large-sample population epidemiological studies for verification, and fully utilize the risk-prediction function to prevent and control ONIHL.

ObjectiveTo analyze the results of fit testing and its influencing factors on half-mask respirator among workers exposed to organic solvents. Methods A total of 84 workers exposed to organic solvents were selected as the research subjects using a convenience sampling method. The qualitative fit test apparatus of respiratory protection was tested after the workers had put on the half-mask respirats, and 11 facial indicators of the subjects were measured. Results The overall pass rate of the respirator fit testing was 71.4% (60/84). The lowest pass rate was 63.1% (53/84), which occurred during bending movements of workers. The head width, minimum forehead width, face length, nose length, nose depth, head circumference and head length were higher in workers who passed respirator fit testing, compared with those in the failing group (all P<0.05). The result of binary logistic regression analysis showed that gender and face width were influencing factors of the respirator fit testing (both P<0.05). Female workers had a lower pass rate of the fit testing than male workers, and workers with larger face width had a lower pass rate in the fit testing. Conclusion Drastic movement may lead to a decrease in the seal of half-mask respirator of workers exposed to organic solvents. When providing half-mask respirator to workers exposed to organic solvents, employers need to pay attention to the fit of respirators of female works and those with larger face width to ensure the effectiveness of respiratory protection for workers.

ObjectiveTo explore the protective effect of hearing protectors worn by noise-exposed workers and its influencing factors. Methods A total of 329 occupational noise-exposed workers were selected as the research subjects by judgment sampling method. A questionnaire survey on the use of ear protectors and individual suitability tests was conducted. Intervention was carried out for those whose personal attenuation rating (PAR) did not pass the baseline standard. Results The median (M) and the 25th and 75th percentiles of baseline PAR were 17.0 (5.0, 22.5) dB. The baseline PAR of the workers who were male, aged 25-<35 years, with a working experience of 5-<15 years, with a college degree or above, wearing ear protectors for 5-<15 years, knowing the right way to wear ear protectors, and workers who wore ear protectors correctly during work was relatively high (all P<0.01). The unqualified rate of baseline PAR of the study subjects was 32.8%. The unqualified rate of baseline PAR of workers in automobile manufacturing enterprises was lower than that of workers in plastic enterprises and textile enterprises (9.2% vs 43.6%, and 9.2% vs 50.0%, both P<0.01). The M of the 108 unqualified worker on baseline PAR was improved after intervention (22.0 vs 1.0 dB, P<0.01). The rates of knowing the right way to wear ear protectors, wearing ear protectors correctly during work, and receiving training on wearing ear protectors correctly for the research subjects were 88.1%, 84.8%, and 86.6%, respectively. Workers in automobile manufacturing enterprises and plastic enterprises had higher rates of knowing the right way to wear ear protectors, wearing ear protectors correctly during work, and receiving training on wearing ear protectors correctly than those in textile enterprises (all P<0.01). Conclusion Gender, age, working experience, education level, duration of wearing ear protectors, knowledge and use of ear protectors correctly are influencing factors of the protective effect of ear protectors for noise-exposed workers.