Abstract: Objective Methods Toevaluatetheriskofhearinglosscausedbyworkplacenoiseinurbanrailtransitenterprises. Noiseexposedworkers from eight rail transit lines in an urban rail transit enterprise was selected as the research subjects - usingconvenientsamplingmethod.Thenoiseintensitywasdetected,andtheriskofnoise inducedhearinglosswaspredictedby Results the method of the International Organization for Standardization. The incidence of noise exceeded the standard detection points was 8.3% (175/2 101) from 2016 to 2018. For risk classification in interval tunnel repairmen, higher risk was predictedattheageof40yearsoldandwiththelengthofserviceof20years,andhighriskwaspredictedattheageof50or60 yearsoldwiththelengthofserviceof30or40years.Theriskclassificationofstationinspectoratthepredictedageof 50years oldandthepredictedageof30yearswasnegligible,anditwasacceptableatthepredictedageof60yearsoldandthepredicted ageof40years.TheriskgradesofmaintenanceworkersinvehicledepotundertheabovetwopredictedconditionsweremediumConclusionrisk,whiletheriskclassificationofdriversunderwasacceptablerisk.Therailtransitenterprisehasacertain degreeofnoisehazardsintheoperationprocess.Theriskanddegreeofhearinglosscausedbynoiseincreaseswiththeincrease ofthelengthofservice.

Objective:To explore the effect of adipose derived mesenchymal stem cells to regulate the differentiation of macrophage RAW264.7.Methods:First,we used RAW264.7 cells to simulate macrophage and induced them to M 1 macrophage with lipopolysaccharide ( LPS,1 μg/ml) .Then we cultured these RAW264.7 cells in culture mediums which were previously used to culture adipose derived mesenchymal stem cells to imitate the transplantation of ADMSC .Last,the mRNA relative expression of IL-10, IGF-1,Arg-1,TNF-α,FIZZ1,SPHK-1 was detected by real-time PCR.The protein expression of IL-12 p40,IL-27 Rα,IL-10 was detected by Western blot.Results:After been cultured in ADMSCCM and induced by LPS ,M1 markers (TNF-αmRNA,IL-12 p40;P<0.05) of the RAW264.7 cells declined while M2 markers (IGF-1 mRNA,IL-10 mRNA,IL-10;P<0.05) rose.Conclusion: ADMSC can secrete soluble cytokines to induce the RAW264.7 cell,which have been induced to the M1 macrophages,to differentiate towards M2 macrophages.