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.

ObjectiveThis study aims to analyze the pharmacodynamic material basis and multi-target mechanism of action of Banxia Baizhu Tianmatang combined with Danggui Shaoyaosan in the treatment of Meniere's disease（MD）. MethodsUltra-performance liquid chromatography-high resolution mass spectrometry （UPLC-HRMS） （mobile phase： gradient elution with 0.1% formic acid aqueous solution-acetonitrile. Mass spectrometry scanning range： m/z 90-1 300） was used to identify the chemical components of the compound recipe and components absorbed into blood. The core mechanism was predicted by combining network pharmacology （target screening via SwissTargetPrediction and GeneCards databases， and construction of protein-protein interaction （PPI） network by STRING） and molecular docking （evaluated by Autodock， with binding energy ≤ -5.0 kcal·mol^-1）. For animal experiment validation， 36 Sprague Dawley （SD） rats were divided into a blank group， a model group （postauricular injection of lipopolysaccharide （LPS） at 1 mg·kg^-1）， low/medium/high-dose Chinese medicine groups （5.94， 11.88， and 23.76 g·kg^-1·d^-1， respectively）， and Western medicine group （betahistine at 0.1 mg·kg^-1·d^-1）. After eight weeks of intervention， the gene and protein expressions in cochlear tissue were detected. Results①A total of 2 831 chemical components and 173 components absorbed into blood were identified， with terpenoids showing the highest absorption rate into blood（10.28%）. ②60 common drug-disease targets were screened， with core targets including tumor necrosis factor-α（TNF-α），interleukin-6（IL-6）， Toll-like receptor 4（TLR4）， angiotensin-converting enzyme（ACE）， and endothelial nitric oxide synthase 3（NOS3）.These targets were enriched in the nuclear factor-κB（NF-κB） signaling pathway and renin-angiotensin system（P<0.05）. Molecular docking showed that the active component YC-1 had a strong binding ability to TNF（binding energy-9.66 kcal·mol^-1）. ③In animal experiments， the high-dose Chinese medicine group significantly down-regulated the expression of pro-inflammatory factors TNF mRNA（P<0.01）and up-regulated vascular regulatory factors NOS3 protein（P<0.01）， and alleviated cochlear pathological damage［hematoxylin eosin （HE） score： from 4 to 2］. ConclusionThis compound recipe synergistically regulates the TNF/NF-κB inflammatory pathway and ACE/NOS3 vascular homeostasis pathway through flavonoids， triterpenoids， and other components， thereby inhibiting endolymphatic hydrops and cochlear damage. It provides a scientific basis for the theory of "simultaneous treatment of phlegm and blood stasis" in traditional Chinese medicine.

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 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.

Objective To analyze the quality of 22 batches of Fritillariae thunbergii bulbus Formula Granules from 12 different manufacturers by using water-extraction reference substance of Fritillariae thunbergii bulbus(ZBM ERS ST)and water-extraction reference substance of Fritillariae hupehensis bulbus(HBBM ERS ST)as references.Methods Ethyl acetate-methanol-triethylamine-water(17∶1∶1∶0.5)was used as the developing solvent for high-performance thin-layer chromatography(HPTLC)fingerprint analysis.The high-performance liquid chromatography(HPLC)fingerprint analysis was performed on a Agilent Eclipse XDB-C18 column(4.6 mm×250 mm,5 μm)with the gradient mobile phase consisted of acetonitrile-0.03%diethylamine solution.The column temperature was set at 25℃and evaporative light-scattering detector was used.The determination was conducted according to standard test method for measurement of Fritillariae thunbergii bulbus Formula Granules(Guangdong PFKL00117).Results The results of HPTLC and HPLC analysis showed that there are significant differences among the 22 batches of Fritillariae thunbergii bulbus Formula Granules.There were 4 batches of Fritillariae thunbergii bulbus Formula Granules from 3 manufacturers among them showed fingerprint characteristics of Fritillariae hupehensis bulbus.The total amount of peimine and peiminine in the remaining 18 batches of Fritillariae thunbergii bulbus Formula Granules was 0.291-3.179 mg·g-1,which were quite different.Conclusion Currently,the quality of Fritillariae thunbergii bulbus Formula Granules on the market varies greatly.Standardized water-extract reference substance has better applicability for the analysis of the quality of Fritillariae thunbergii bulbus Formula Granules than the control medicinal materials.

ObjectiveTo analyze the spectrum distribution characteristics of high-intensity productive noise in key industries in Guangdong Province. Methods A total of 2 806 enterprises in 21 prefecture-level cities in Guangdong Province were selected as the study subjects using the stratified sampling method. On-site investigations were conducted in workplaces. Noise in workplaces and work-sites, and the noise spectrum of the workplaces with sound pressure level ≥85.0 dB(A) were detected. Results The noise of a total of 23 076 workplaces and 20 969 work sites from 30 key industries were monitored. The median (M) and 25th and 75th percentiles (P₂₅, P₇₅) of workplace sound pressure level were 82.3 (78.6, 86.5) dB(A). The rate of the noise exceeded national standard was 30.4%. The sound pressure level M (P₂₅, P₇₅) of work-site was 78.6 (70.0, 83.5) dB(A). The rate of the noise exceeded national standard was 18.0%. Workplace noise and work site noise were positively correlated (Spearman correlation coefficient=0.86, P<0.01). The rate of the noise exceeded national standard was 46.5% in key work sites where the rate of noise exceeded the national standard was ≥25.0%, and corresponding rate of the workplace noise exceeded national standard was 58.1%. The noise spectrum result of 5 636 workplaces sound pressure level>85.0 dB(A) showed that most of the noise source was from grinding machines (441 cases), and the highest average sound pressure level of noise source was from screening machines [93.0 dB(A)]. Cluster analysis results showed that the main noise sources could be divided into three categories, including wideband noise with levels >80.0 dB in all frequency bands except 8 000.0 Hz, medium-high-frequency noise with the highest sound pressure level at 1 000.0, 2 000.0, and 4 000.0 Hz and low frequencies <75.0 dB, and medium-low-frequency noise below 500.0 Hz with sound pressure level >85.0 dB. Conclusion The rate of the noise exceeded national standard in workplace of key industries in Guangdong Province is high, involving a wide range of industries, with high sound pressure levels and obvious spectrum characteristics of corresponding noise sources. Corresponding noise control strategies can be formulated based on different spectrum characteristics and magnitudes.

Objective:To investigate the application of "micro ward" teaching based on the concept of dedicated education units (DEU) in the standardized training of neurosurgery residents.Methods:The 22 neurosurgery residents enrolled in 2021 for standardized training were assigned to the control group with traditional teaching method. The 24 neurosurgery residents enrolled in 2022 were assigned to the observation group with the "micro ward" teaching method based on the DEU concept. The theoretical knowledge and operational skill scores, clinical thinking ability, and teaching satisfaction were compared between the two groups of students before and after the training. SPSS 21.0 was used to perform chi-square test, Z test and t test. Results:The observation group had higher scores in terms of surgical skills [(190.63±4.35) vs. (86.79±4.82)] and case analysis [(190.54±5.06) vs. (86.13±5.35)] than the control group ( P<0.05). The scores were higher in the observation group than in the control group in terms of broadening thinking, overall thinking, curiosity, and cognitive maturity after training ( P<0.05). The observation group had a significantly higher proportion of students who were satisfied with standardized neurosurgery training teachers, teaching methods, and teaching results than the control group ( P<0.05). Conclusion:The application of "micro ward" teaching based on the concept of DEU in the standardized training of neurosurgery residents can effectively improve the clinical practice ability and professional quality of trainees, cultivate their specialized clinical thinking, enhance their independent learning ability, and improve the training quality. Therefore, this teaching method is worth promoting.

Objective     To identify the heart sounds of aortic stenosis by deep learning model based on DenseNet121 architecture, and to explore its application potential in clinical screening aortic stenosis. Methods      We prospectively collected heart sounds and clinical data of  patients with aortic stenosis in Tianjin Chest Hospital, from June 2021 to February 2022. The collected heart sound data were used to train, verify and test a deep learning model. We evaluated the performance of the model by drawing receiver operating characteristic curve and precision-recall curve.  Results     A total of 100 patients including 11 asymptomatic patients were included. There were 50 aortic stenosis patients with 30 males and 20 females at an average age of 68.18±10.63 years in an aortic stenosis group (stenosis group). And 50 patients without aortic valve disease were in a negative group, including 26 males and 24 females at an average age of 45.98±12.51 years. The model had an excellent ability to distinguish heart sound data collected from patients with aortic stenosis in clinical settings: accuracy at 91.67%, sensitivity at 90.00%, specificity at 92.50%, and area under receiver operating characteristic curve was 0.917.   Conclusion     The model of heart sound diagnosis of aortic stenosis based on deep learning has excellent application prospects in clinical screening, which can provide a new idea for the early identification of patients with aortic stenosis.

Objective: To analyze the status of noise hazard in workplace of key industries in Guangdong Province. Methods: A total of 1 061 enterprises from 14 key industries in 21 prefecture-level cities in Guangdong Province were selected as the research subjects using stratified sampling method. The occupational health survey was carried out, and the noise intensity in the workplace was detected. Results: There were 12 606 workplaces and 5 570 work sites involved among 1 061 enterprises. The median and the 0-100th percentile value ［M (P₀-P₁₀₀)］ of noise intensity in workplace were 82.6 (46.5-112.6) dB(A), and 35.03% of the workplace exceeded the national noise intensity standard. The regions and industry with the highest rate of noise exceeded the national noise intensity standard in workplace were in the northern part of Guangdong and the stone processing industry respectively. The M (P₀-P₁₀₀) of noise intensity in the work sites was 83.7 (47.5-106.2) dB(A), and 36.00% of the work sites exceeded the national noise intensity standard. The regions and industry with the highest rate of noise exceeded the national noise intensity standard in work sites were in the Pearl River Delta region and the ferrous metal mining and dressing industry respectively. The rate of noise protection facilities setting was 66.45%, and the validity of personal protection was 61.73%. The occupational medical examination was performed in 73.24% of the research subjects, and 3.25% of the result was abnormal. The industry with the highest occupational medical examination rate was nonferrous metal smelting and rolling processing, and the industry with the highest abnormal rate of occupational medical examination was stone processing industry. Conclusion: Noise hazards in workplaces of key industries in Guangdong Province are relatively severe, necessitating strengthened supervision and management, noise control measures, and efforts to reduce noise exposure levels in workplaces and work sites.

{L-End}Objective To analyze the characteristics of hearing loss and the influencing factors of high-frequency hearing loss (HFHL) among noise-exposed workers in an urban rail transit enterprise over five consecutive years. {L-End}Methods A total of 1 268 noise-exposed workers, who exposed to the average noise intensity of <85.0 dB(A), in an urban rail transit enterprise was selected as the research subjects using a judgment sampling method. The pure-tone audiometry results from 2019 to 2023 were collected to analyze the result of hearing loss. The influencing factors of HFHL (average hearing threshold ≥40.0 dB at high frequencies in both ears) were analyzed using the generalized estimating equations (GEE). {L-End}Results The detection rates of threshold elevations at frequencies of 0.5-6.0 kHz increased with increasing frequency from 2019 to 2023 (all P<0.01), with the highest detection rate at 6.0 kHz. The detection rate of speech frequency hearing loss (hearing threshold weighted value≥26.0 dB in the better ear) was 0.1%, 0.0%, 0.4%, 0.2%, and 0.2%, respectively. The detection rate of HFHL from 2019 to 2023 was 2.4%, 2.8%, 2.8%, 2.1%, and 2.8%, respectively. The GEE analysis results showed that the risk of HFHL of the workers in 2022 and 2023 was lower than that in 2019 (all P<0.01), with the odds ratios and 95% confidence intervals ［OR (95%CI)］ of 0.57 (0.41-0.81) and 0.65 (0.48-0.87), respectively. The risk of HFHL was higher among vehicle maintenance worker than train drivers (P<0.05), with OR (95%CI) of 2.37 (1.18-4.77). The risk of HFHL increased with age and length of service among the workers (all P<0.05), with the OR (95%CI) of 2.05 (1.22-3.46) and 1.69 (1.12-2.54), respectively. No interaction was found between type of job and age, type of job and length of service, or age and length of service in the risk of HFHL among the research subjects(all P<0.05). {L-End}Conclusion Noise exposure below the national occupational exposure limits can lead to hearing loss in noise-exposed workers of urban rail transit enterprises, possibly affecting the hearing threshold at 6.0 kHz first. The influencing factors for HFHL in workers of rail transit are age, length of service, and type of job. There is a dose-effect relationship with age and length of service.