OBJECTIVE: To study the combined effect of noise and hydrogen cyanide on noise-induced hearing loss( NIHL)in a metal electroplating enterprise. METHODS: The judgment sampling method was used to select 663 workers in a largescale metal electroplating enterprise as the study subjects. Among them,186 workers exposed to noise alone were designated as noise group; 138 workers exposed to hydrogen cyanide alone were designated as hydrogen cyanide group; and161 workers exposed to noise and hydrogen cyanide were designated as combined effect group,and 178 workers without exposure from occupational disease risk factors were designated as control group. Questionnaires survey and pure tone audiometry were used for analyzing the effects of combined noise and hydrogen cyanide exposure on NIHL. RESULTS: The hearing loss detection rate of the study subjects was 40. 4%. The hearing loss detection rates in the control group,noise group,hydrogen cyanide group,and combined effect group were 17. 4%,47. 8%,32. 6% and 64. 0%,respectively. The detection rate of hearing loss in the control group was lower than that in the other three groups( P < 0. 008). The NIHL detection rates in the combined effect group and the noise group were higher than that in the hydrogen cyanide group( P <0. 008). The hearing loss detection rate of the combined effect group was higher than that of the noise group and the hydrogen cyanide group( P < 0. 008). Ordinal multi-categorical logistic regression model results showed that after adjusting confounding factors such as age,length of service,gender,marital status,smoking,alcohol drinking,we found hydrogen cyanide exposure,noise exposure,and combined exposure to hydrogen cyanide and noise had effects on workers' hearing(P < 0. 05). The risk of hearing loss in workers exposed to noise and hydrogen cyanide was higher than that of workers exposed to noise alone or hydrogen cyanide alone. CONCLUSION: There is a combined effect of noise and hydrogen cyanide in this metal electroplating enterprise,which can increase the risk of NIHL in workers.

OBJECTIVE：To explore the metabolic charact eristics of Miao medicine Laportea bulbifera extract in isolated human intestinal flora. METHODS ：L. bulbifera was extracted with 70％ ethanol reflux extraction. After concentration，extraction with n-butanol and drying ，L. bulbifera extract was obtained. Taking 0.05 g/mL L. bulbifera extract 1 mL mixed with isolated human intestinal flora fluid 10 mL and cultured for 36 h in anaerobic environment （setting up blank control without drugs or human intestinal bacterial solution ），so as to simulate the metabolic process of the extract in human intestine. The metabolites were detected by UPLC-Q-TOF/MS. The determination was performed on Agilent Eclipse Plus C 18 RRHD column with mobile phase consisted of 0.01％ formic acid water solution- 0.01％ formic acid acetonitrile solution （gradient eluetion ）at the flow rate of 0.25 mL/min. The column temperature was set at 40 ℃，and the sample size was 1 µL. ESI detection was adopted and scanned by negative ion mode （ESI－）；the capillary voltage was 4.5 kV，the ion source temperature was 120 ℃，the collision energy was 15-32 V，and the scanning range was m/z 50-1 000. The “Strip”module of MassLynx V 4.1 software was used to analyze the differential chromatograms between the reaction solution and the blank control of L. bulbifera extract. Mass spectrum data and UNIFI so ftware were used to predict relative molecular weight and formula ；based on the information of substance control and related literature reports ， the structure and biotransformation pathway of L. bulbifera metabolites in isolated human intestinal flora were predicted and analyzed. RESULTS & CONCLUSIONS ： A total of 3 prototype ： products（rutin，quercetin，kaempferol-3-O-rutinoside）and 22metabolites （mainly the metabolites of quercetin ，mono- caffeoylquinic acid ，isoquercitrin，etc.） were detected after metabolized in isolated human intestinal flora. Itsbiotransformation pathway is phase Ⅰ reaction，which mainly consisted of reduction ，oxidation and hydrolysis.