ABSTRACT
Objective To evaluate the noise hazard level of a coal mining enterprise, and identify high-risk operation types and people, and to provide a basis for preventing and controlling the health damage caused by noise. Methods A large coal mining enterprise in Shaanxi Province was selected as the research object. The noise monitoring data of the coal mine over the years was used to calculate the noise exposure matrix of each post in the enterprise, and the classification of occupational hazards at workplaces (GBZ/T 229.4-2012) was used to assess the occupational health risk levels. Results Among the 22 noise-exposed positions in the enterprise, the 8-hour working day equivalent sound level in positions of shearer driver, horseshoe driver, crusher driver, shuttle driver, relaxation screen driver, and grading screen driver were all higher than the occupational exposure limit of noise. In 2021, the noise exposure levels of shearer drivers, crusher drivers, and coal-selecting workers were all higher than 90 dB (A), and the occupational hazard level was moderate hazard level. In addition, the noise exposure levels of most other jobs also exceeded the occupational exposure limit. Conclusion The noise hazards in the coal mine industry are mainly concentrated in the posts of the coal mining system, tunneling system, and screening workshop. Among them, the shearer driver, the crusher driver, and the coal preparation workers have higher noise exposure levels. It is recommended to take corresponding noise reduction measures and strengthen the protection level to reduce the noise exposure risk of workers.
ABSTRACT
Objective To investigate the neuroprotective effect of cattle encephalon glycoside and ignotin injection on the rat model of traumatic brain injury (TBI).Methods Three hundred and six SD rats were randomly divided into sham group,TBI group,high dose group,middle dose group and low dose group according to the random number table.Rats received 1.8,0.6 and 0.2 ml/kg of cattle encephalon glycoside and ignotin injection for 28 days in high,middle and low dose groups,respectively.TBI was induced by the modified Feeney' s weight-drop method.Rat mortality,neurological function score and learning and memory ability were recorded.Brain morphological changes were evaluated with 7.0 T small animal nuclear magnetic resonance and HE staining.Evans blue was applied to assess blood brain barrier (BBB) permeability and hydrocephalus was evaluated by the brain water content.Results Mortality in high dose group decreased significantly compared to that in TBI group (22.40％ vs.28.14％,P ＜ 0.05).Defects in neurological function and learning and memory induced by TBI were significantly mitigated in middle and high dose groups (P ＜ 0.05).Pathological damage and contralateral hippocampal atrophy in middle and high dose groups were reduced significantly compared to TBI group (P ＜ 0.05).Hippocampus neuroapoptosis in middle and high dose groups was significantly improved compared to TBI group (P ＜ 0.05).BBB damage was less severe in middle and high dose groups than in TBI group (P ＜ 0.05).The treatment was preventive against secondary hydrocephalus.Conclusion Middle or high dose cattle encephalon glycoside and ignotin injection over a 28-day period has significant neuroprotective effect on the TBI rats.