Occupational noise exposure and hearing loss: A study on knowledge, attitude and practice among Tanzanian iron and steel workers

We assessed Knowledge Attitude and Practice (KAP) regarding occupational noise exposure, Noise-induced hearing loss, audiometry and use of hearing protection devices among iron and steel factory workers exposed to high noise level. A modified, validated, structured questionnaire was used to collect information from 253 male workers randomly selected from the four factories. The sum scores for each domain of KAP were computed. Scores above 75% were defined as good knowledge and positive attitude. For practice, scores of >50% were defined as good. Independent samples t-test and Chi-squared test were used to analyze association between KAP and continuous/categorical variables respectively. Majority of workers displayed poor knowledge and poor practice (94%), but 76% displayed a positive attitude. Most of the workers (86%) had never been provided with hearing protection devices. The mean scores for attitude and practice differed significantly between the four factories (one-way ANOVA, p < 0.001). Implementation of hearing conservation program with provision of hearing protection devices are suggested.publishedVersio

Validation of Noise Induced Hearing Loss Questionnaire Among Malay Sawmill Workers in Kelantan Malaysia

Exposure to excessive noise is the major avoidable cause of permanent hearing impairment. Sawmill is one of the workplaces where workers are exposed to hazardous noise level. This study was conducted to determine the reliability and validity of noise-induced hearing loss questionnaire among sawmill workers. Materials and Methods: This cross sectional study was conducted in March 2007 among 35 consented sawmill workers. A total of 40 items; 10 items for knowledge (8 areas), 20 items for attitude (7 areas) and 10 items for practice (2 areas) were assessed. Statistical analysis for reliability analysis was test by internal consistency and construct validity by exploratory factor analysis using principal components and Varimaxrotation method. Results: Cronbach’s alpha coefficients were acceptable for attitude (0.90) and practice (0.75). However, it was low for knowledge (0.67). Exploratory factor analysis showed three meaningful exploratory factors that could explain the three dimensions in the questionnaire. Conclusion: The results of the validation study suggested that the noise-induced hearing loss questionnaire is reliable and valid tool for assessing knowledge, attitude and practice among sawmill workers

Arterial Stiffness and its Association with Dyslipidemia

ABSTRACT Introduction: Cardiovascular diseases (CVD) are the leading cause of mortality in Malaysia as well as in other countries. It is associated with many risk factors, such as increasing age, hypertension, diabetes, dyslipidemia, oxidative stress and autonomic dysfunction and arterial stiffness. The objectives of this study were to measure the prevalence of arterial stiffness and to assess its association with dyslipidemia. Methods: A cross sectional study was conducted in a rural community in Malaysia involving 146 subjects. Data were collected using an interviewer administered questionnaire which included three sections -sociodemographic characteristics, personal profile, and past medical history. In addition, Seca Body Meter (Seca 220) was used to measure height and weight. Sphygmomanometer (OMRON Automatic Blood Pressure Monitor HEM 907) and SphygmoCor-AtCor MM3 SERIAL/RS-232 were used for blood pressure and augmentation index (AIx) measurement. Data were analysed using the SPSS for Windows, Version 18.0. Results: The mean age of respondents was 49.5 years, SD±15.6. The prevalence of arterial stiffness was 23.3% (95% Confidence Interval (CI): 16.44 -30.16). The prevalence of dyslipidemia was 82.9% (95% CI: 76.79 -89.01). Multivariate logistic regression revealed that total cholesterol was significantly associated with arterial stiffness (OR=4.56, CI 1.10-18.90). Conclusion: The prevalence of dyslipidemia was high. Despite an insignificant association between dyslipidemia and AIx, there is a significant association between TC level and AIx

An Improved Switching Control Technique for Single-Phase Voltage Source Inverter

&copy; 2020 IEEE. The traditional pulse width modulation techniques cause high power loss in the power devices of the inverter. This paper presents a modified equal loading bus clamping pulse width modulation technique, where the modulating voltage is clamped to its dc bus voltage for 120 degree in each half cycle of the fundamental period. Consequently, the switching loss of the inverter is greatly reduced, which in turn increases the inverter overall efficiency and active life time. Also, the total harmonic distortion of the converter is also improved. Furthermore, the dc bus voltage utilization is around 81.6%. The improved performance of the proposed technique is validated by simulation in MATLAB/Simulink