[Characteristics at different frequencies of hearing loss in noise exposure workers of the automobile manufacturing industry].

Objective: To analyze the effects of noise exposure on the hearing at different frequencies in workers from the automobile manufacturing industry. Methods: A total of 4723 noise workers in a large automobile manufacturing company in Guangzhou were chosen as the research object by using judgment sampling method between April and July, 2018, and carried out 0.5, 1.0, 2.0, 3.0, 4.0 and 6.0 kHz pure tone audiometry threshold to analyze the characteristics of the status of hearing loss at different frequencies and its relationship with the noise exposure time. Results: The detection rate of hearing loss in noise-exposed workers was 29.8% (1406/4723) . Among them, the binaural hearing loss was 21.2% (999/4723) , and single unilateral hearing loss accounted for 8.6% (407/4723) . The hearing loss detection rate of right ear was higher than that of the left ear (P<0.05) , especially in the 6.0 kHz (P<0.001) . The detection rate of increased speech frequency hearing threshold was 1.9% (90/4723) , and the detection rate of increased high-frequency hearing threshold was 28.9% (1366/4723) . The detection rate of increased threshold in both the left and the right ear increased with the increase of frequency (P<0.001) , the increased hearing threshold was the highest at the frequency of 6.0 kHz. The auditory threshold of left ear in 0.5 kHz were higher than that of right ear at the same frequency (P<0.05) . The detection rate of hearing loss increased with the increase of noise exposure time (P<0.001) , and the increased threshold of 3.0, 4.0 and 6.0 kHz from workers increased with the increase of noise exposure time (P<0.001) . Conclusion: There is a significant increased threshold in workers exposed to noise frequency of 6.0 kHz, right ear is more easily damaged than left ear, there is a dose-response relationship for the noise exposure time and high-frequency hearing loss.

[Effect of low dose ionizing radiation on peripheral blood cells of radiation workers in nuclear power industry].

Objective: To investigate the effects of long-term ionizing radiation on peripheral blood cells of nuclear power workers. Methods: In March 2019, a total of 530 radiation exposed workers in the nuclear power industry who underwent in-service radiation occupational health examination in Guangzhou occupational disease prevention and control hospital in 2018 and with service age ≥1 year were selected as the radiation group. At the same time, 545 workers in nuclear power industry were selected as control group. According to the methods and requirements of GBZ 235-2011 ＂technical specification for occupational health monitoring of radiation workers＂ and GBZ 98-2017 ＂health requirements for radiation workers＂, the occupational health monitoring data were collected, and the change rules of peripheral blood cells in the two groups were analyzed. Results: Compared with the control group, the total number of WBC, NEUT, LYMP, Hb, MCV and MCHC in radiation group were lower than those in control group (P<0.05) , and the difference was statistically significant (P<0.05) . The MPV increased significantly (P<0.05) . Compared with the control group, the abnormal rate of WBC and Hb in the radiation group was higher than that in the control group (P<0.01) , but there was no significant difference in the abnormal rate of RBC and PLT (P>0.05) . Conclusion: Low dose ionizing radiation has a certain cumulative damage effect on peripheral blood cells of radiation workers in nuclear power industry. The change rules of different cell subtypes are different, and the changes of WBC and PLT appear earlier.

Amperometric glucose enzyme electrode by immobilizing glucose oxidase in multilayers on self-assembled monolayers surface.

A novel and robust amperometric enzyme electrode for the determination of glucose was constructed by immobilizing glucose oxidase (GOD) and Os(bpy)(2)Cl-poly(4-vinyl)pyridine (Os-PVP) complex multilayers on thiol self-assembled monolayers surface. The apparent Michaelis-Menton constant K(m)' increased with increasing the number of Os-PVP/GOD multilayers. The concentration range of linear response and detection limit were 0.1-10 and 0.05 mM, the interference of ascorbic acid and uric acid were eliminated by the presence of SAMs and the enzyme electrodes were stable over 3 weeks. The preparation technique may be useful for controlling the performance of multilayer enzyme electrodes by changing the enzyme content.

[Immunological injury from serum sickness on aortic connective tissue components].

Changes of aortic proteoglycan, collagen and elastic fibers following immunological injury were studied quantitatively and qualitatively under electron microscope after ruthenium red labelling. The results showed that repeated intravenous injections of bovine serum albumin in rabbits activated the synthesis of collagen, elastic fibers and proteoglycan in the aortic wall. The increase of connective tissue components was coincident with the morphological changes of smooth muscle cell.