[Study on the Wavelength Selection Based on VIP Analysis in Noninvasive Measurement of Blood Components].

Selection of independent variable is a hotspot in the field of quantitative spectral analysis. Efficient and easy-to-use method for wavelength selection can not only reduce the computation and improve the accuracy of analysis, but also can reduce dependency on the spectral resolution of instruments and cut cost. Wavelength selection is also an important part of the research about noninvasive measurement of blood components by spectrum technology. Dynamic Spectrum theory provides excellent ideas for researchers, but only broadband light source and high-resolution spectrograph were used in correlational studies for a long time. The large number of wavelengths needed for analysis limits the further development of Dynamic Spectrum method. In order to remove redundancy information and make the devices low-cost and integrated, the method of Wavelength selection on the basis of Variable Importance in Projection (VIP) analysis was proposed. Variables with less importance were removed and wavelengths with great explanation power were retained after VIP analysis the number of wavelengths was reduced from 586 to 64. PLS model with 64 wavelengths get a satisfactory predict result that the MREP is 1.82%. The significance test through Bootstrap method validate the selected wavelengths' explanation power. Moreover, the study pointed out the sensitive wavelengths in Dynamic Spectrum method for the first time. Study also took the first step toward the practical application of Dynamic Spectrum and laid the foundation of low-cost on-line analysis, and it also provided valuable references and new ideas for spectral analysis in other areas.

[A study on the relationship between hearing impairment and blood pressure and hypertension in workers occupationally exposed to noise].

OBJECTIVE: To study the correlation between noise and blood pressure and/or hypertension, and its age characteristic. METHODS: The pure tone audiometric and blood pressure examinations were performed in 14537 workers from 157 factories. Hearing impairment was used as a surrogate indicator of cumulated noise exposure. The associations of hearing impairment and duration of noise exposure with blood pressure and hypertension were analyzed respectively after age and gender stratification. RESULTS: Most of the objects were males (81.2%), younger than 35 years old (77.8%), and the duration of exposure to noise was less than 5 years (73.6%). The prevalence of hearing impairment in males was significantly higher than that in males, and increased with age and duration of noise exposure. Only in males with age younger than 35 years old, the systolic and diastolic blood pressures of subjects with sensorineural hearing loss significantly enhanced, and the diastolic blood pressure and prevalence of hypertension increased with duration of noise exposure. The risk of hypertension in males with sensorineural hearing loss significantly increased, the odds ratios in subjects with age younger than 35 years old and with age older than 35 years old were 3.0 (95%CI: 1.5 ∼ 6.1) and 2.1 (95%CI: 1.2 ∼ 3.4), respectively. CONCLUSION: The severe hearing impairment induced by noise was associated with hypertension. It is suggested that people should pay attention to the effects of noise on hypertension in young workers.

[Effect of environmental risk factors in occupational noise exposure to noise-induced hearing loss].

OBJECTIVE: To observe the effect of environmental risk factors in occupational noise exposure on hearing loss and find out the susceptible population of noise induced hearing loss (NIHL). METHODS: A case-control study was designed to study the effect of environmental risk factors on NIHL. 2400 workers exposed to 75 approximately 120 dB noises from an air conditioning factory in southern China served as the subjects. 202 workers were selected from 10% of population with the maximum hearing shift of the left ear to 3000 Hz noises as the NIHL susceptible group while 204 workers from 10% of population with the least hearing shift as the NIHL tolerant group. A questionnaire was designed to carry out an investigation, and an occupational health survey was used to identify the occupational risk factors which might affect the hearing system. The univariate analysis and multivariate analysis were used to observe the effect of environmental risk factors on NIHL. RESULTS: The results of univariate analysis showed that smoking, alcohol drinking, organic solvent, heavy metal, heat, dust were significantly was associated with NIHL (P < 0.05). Multivariate analysis showed that only heat was associated with NIHL (P < 0.05), and OR value was 1.804 (95% CI: 1.101 approximately 2.958). CONCLUSION: Exposure to heat may be a high risk factor of NIHL.