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.

Objective:To assess the efficacy of silicone earplugs in protecting workers exposed to noise in a typical manufacturing environment, and to provide training interventions for workers who do not achieve the anticipated noise reduction levels, as well as examining the spectral characteristics of earplug attenuation.Methods:From June to August 2022, a total of 294 noise-exposed workers in two manufacturing enterprises equipped with the same type of earplug were studied by cluster sampling method, by conducting questionnaire surveys, collecting data, fitting tests, and providing trainings, the current noise exposure levels of workers in the industry as well as the perception about the earplug were understood. Additionally, the attenuation before and after intervention in workplace were measured, the spectral characteristics of noise reduction were were described and compared.Results:The percentage of workers with Personal Attenuation Rating (PAR) of 0 is 32.7% (96/294), and the baseline pass rates are all below 60%. There were no significant differences in pass rates based on gender, age, noise exposure, education level, or cognition of earplug effectiveness. After adjusting the way that earplugs are worn or changing the type of earplugs, all workers were able to meet their noise reduction requirements. The median PAR improvement for both companies is above 10 dB. The noise attenuation of the earplug vary with frequency, with lower attenuation at 4 000 Hz and higher attenuation at 8 000 Hz, showing some deviation from the nominal values.Conclusion:The difference between the actual sound attenuation value of earplugs and the nominal value is related to the noise frequency. When using silicone earplugs, attention should be paid to the spectral composition of the noise in the workplace.

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.

Objective:To assess the efficacy of silicone earplugs in protecting workers exposed to noise in a typical manufacturing environment, and to provide training interventions for workers who do not achieve the anticipated noise reduction levels, as well as examining the spectral characteristics of earplug attenuation.Methods:From June to August 2022, a total of 294 noise-exposed workers in two manufacturing enterprises equipped with the same type of earplug were studied by cluster sampling method, by conducting questionnaire surveys, collecting data, fitting tests, and providing trainings, the current noise exposure levels of workers in the industry as well as the perception about the earplug were understood. Additionally, the attenuation before and after intervention in workplace were measured, the spectral characteristics of noise reduction were were described and compared.Results:The percentage of workers with Personal Attenuation Rating (PAR) of 0 is 32.7% (96/294), and the baseline pass rates are all below 60%. There were no significant differences in pass rates based on gender, age, noise exposure, education level, or cognition of earplug effectiveness. After adjusting the way that earplugs are worn or changing the type of earplugs, all workers were able to meet their noise reduction requirements. The median PAR improvement for both companies is above 10 dB. The noise attenuation of the earplug vary with frequency, with lower attenuation at 4 000 Hz and higher attenuation at 8 000 Hz, showing some deviation from the nominal values.Conclusion:The difference between the actual sound attenuation value of earplugs and the nominal value is related to the noise frequency. When using silicone earplugs, attention should be paid to the spectral composition of the noise in the workplace.

At present, China has not yet established a comprehensive standard and evaluation system specifically for occupational health engineering ventilation inspection. In order to meet the requirements for the design of occupational-disease-prevention facilities, the evaluation of occupational disease hazard control effectiveness, and the protective facilities, the Guangdong Provincial Occupational Health Technical Quality Control Center developed the Guangdong Province Occupational Health Engineering Ventilation Inspection Work Specification (Trial) by referring domestic and international standards and norms related to occupational health engineering, industrial ventilation design manuals and professional literature, using brainstorming and experience-based methods. The work specification covers the key detection indicators of ventilation systems, and comprehensively covers the core links of occupational health engineering ventilation testing. The relevant indicators mainly include: detection of air velocity control; wind speed and air volume of exhaust hoods and exhaust vents of ventilation facilities; detection of wind pressure, wind speed and air volume inside the ventilation duct; fresh air volume detection; and calculation and evaluation of ventilation frequency. The specification is highly practical, indicting scientific and advanced principles, and ensures the fairness and reliability of the testing process and results. Its implementation will effectively promote the standardization and professionalism of occupational health engineering ventilation testing, providing robust technical support for safeguarding workers' health.

Multimodal analgesia is the gold standard for postoperative pain management,and ultra-sound-guided nerve block as the cornerstone supplemented with fewer opioids and a sufficient amount of non-steroidal anti-inflammatory drugs(NSAIDs)throughout the entire course of the procedure is the most main-stream multimodal analgesic regimen at present.However,ultrasound-guided nerve blocks are limited by the duration of action of local anesthetics and often provide effective analgesia for surgical patients for no more than 8 hours,resulting in a low satisfaction rate of postoperative analgesia in surgical patients.With the con-tinuous research on the concept of rapid rehabilitation,how to extend the duration of action of local anesthet-ics is the focus and hotspot of research.Ultra-long-acting local anesthetics include liposomal bupivacaine and HTX-011,which have been applied in clinical practice,and quaternary ammonium derivatives,which are still in the research stage.In this paper,we will review the existing ultra-long-acting local anesthetics in terms of ultra-long-acting local anesthetics with extended-release systems,new pathways and targets of ultra-long-acting local anesthetics,and the development of ultra-long-acting local anesthetics in the form of brand-new compounds,so as to provide new ideas for the subsequent research and clinical application of ultra-long-acting local anesthetics.

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.

Objective:To investigate the value of radiomics signatures based on 18F-FDG PET/CT for predicting molecular classification and Ki-67 expression of breast cancer. Methods:A total of 134 female patients ((55.4±13.3) years) who underwent 18F-FDG PET/CT examination and were diagnosed with breast cancer by pathology in the First Affiliated Hospital of Soochow University from April 2016 to May 2023 were retrospectively enrolled. LIFEx software was used to extract radiomics features and the least absolute shrinkage and selection operator (LASSO) algorithm and independent-sample t test were used to screen potentially meaningful features and calculate the radiomics score, which were considered as radiomics models. Clinical characteristics were selected by supervised logistic regression and clinical models were established. Radiomics features and clinical characteristics were incorporated to logistic regression analysis to establish combined models. ROC curves were drawn and the differences among AUCs were analyzed by Delong test. Results:Among 134 patients, 22 were with triple negative breast cancer (TNBC), 47 were human epidermal growth factor receptor 2 (HER2) over-expression type, 37 were Luminal A type and the rest 28 were Luminal B type. The expression of Ki-67 was high in 85 patients, and was low in the rest 49 patients. The AUCs (95% CI) of the combined models for predicting TNBC, HER2 overexpression type, Luminal A type and Ki-67 expression were 0.843(0.770-0.900), 0.808(0.723-0.876), 0.825(0.711-0.908) and 0.836(0.762-0.894), respectively, which were higher than those of clinical models ( z values: 1.97-3.06, all P<0.05). Conclusion:The predictive model combining radiomics signatures based on 18F-FDG PET/CT and clinical characteristics can well predict the molecular classification and Ki-67 expression level of breast cancer.