• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.1
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• pp.1-7
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• 2005

Although the Fourier Transform Infra-Red spectrophotometric Direct on Filter(FTIR-DOF) method is a useful analytical technique for quantifying quartz content in respirable dust samples, a number of analytical problems must be taken into consideration such as, to name only a few, inhomogeneous deposition of particles, level of environmental humidity, uneven surface of the filter, and interfering minerals in the sample. This study was designed to select the most suitable wavelength and proper filter material for the method, and to investigate effects of humidity and inhomogeneous deposition of particles on the filter. Samples of respirable dust, created in a dust chamber containing standard material of quartz, were collected using a cyclone equipped with a 25mm filter as a collection medium. The results were as follows; 1. Among seven (7) commercially available filters tested for the FTIR-DOF method, the DM 800 filter showed the best analytical performance having the lowest background absorbance bands and no overlapping peaks at 799, 779, and $695cm^{-1}$. 2. The variations of absorbance due to humidity ranged from 1.0% to 3.3% for $799cm^{-1}$, 1.0% to 3.3% for $779cm^{-1}$, and 8.9%~20.9% for $695cm^{-1}$ peaks, respectively. The $699cm^{-1}$ peak was proved to be most vulnerble to environmental humidity for quantitative analysis of quartz. 3. As for effects of inhomogeneous deposition of samples, the highest variation of absorbance of 10.9% ($13.5{\mu}g$) was observed when using the 695cm-1. The variations of absorbance from the other two peaks, 799 and $779cm^{-1}$, ranged from 1.2 to 3.2%, and 1.4 to 4.1%, respectively. Therefore, the $799cm^{-1}$ peak was considered to be most reliable for quantitative analysis of quartz. The results of this study suggest that, for quantitative analysis of quartz in the respirable dust samples, use of the $799cm^{-1}$ peak can minimize the influence of environmental humidity and inhomogeneous deposition of particles on the filter. The FTIR-DOF method, if adopted for routine analysis of quartz in the respirable dust samples, could save sample preparation time and efforts substantially and also could increase analytical throughputs. Since use of the $799cm^{-1}$ peak is prone to be affected by interferences in the sample, further research on minimizing the effects is needed.

• Journal of radiological science and technology
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• v.40 no.3
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• pp.469-484
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• 2017

Radiological Technologists deals with the life of a person which means professional competency is essential for the job. Nevertheless, there have been no studies in Korea that identified the job competence of radiologists. In order to define the core job competencies of Korean radiologists and to present the factor models, 147 questionnaires on job competency of radiology were analyzed using 'PASW Statistics Version 18.0' and 'AMOS Version 18.0'. The valid model consisted of five core job competencies ('Patient management', 'Health and safety', 'Operation of equipment', 'Procedures and management') and 17 sub - competencies. As a result of the factor analysis, the RMSEA value was 0.1 and the CFI, and TLI values were close to 0.9 in the measurement model of the five core job competencies. The validity analysis showed that the mean variance extraction was 0.5 or more and the conceptual reliability value was 0.7 or more, And there was a high correlation between subordinate competencies included in each subordinate competencies. The results of this study are expected to provide specific information necessary for the training and management of human resources centered on competence by clearly showing the job competence required for radiologists in Korea's health environment.

• Journal of Environmental Health Sciences
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• v.46 no.1
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• pp.103-109
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• 2020

Objectives: Using as a sleep evaluation tool the Pittsburgh Sleep Quality Index (PSQI), this paper studied the effects of earthing on the amount and quality of sleep by examining a patient population of people who used and did not use earthing mats and a group of general healthy people. Methods: From September to November 2019, 30 patients who voluntarily used an earthing mat, 40 patients who did not use an earthing mat, and 40 healthy people who did not use an earthing mat were selected. A questionnaire applying the PSQI (Pittsburgh Sleep Quality Index) after being translated into Korean was distributed starting November 29, 2019 to 110 subjects. Out of them, 101 subjects who completed the questionnaire were examined. All statistics used SPSS 25.0. Results: The first overall score showed that all three groups had problems sleeping, with five points or more, but the general population had better sleep quality than the patient group. It also showed that the using matgroup had better quality of sleep than the ones that did not use the earthing mat In addition, the analysis of the third group through the variance analysis showed significance at >0.05 for the general population and the patient group. Based on this, a multi-comparison analysis of the third group showed significantly less than 0.05 in patients who do not use an earthing mat compared to the public. First of all, there are no statistically significant differences between the three groups in subjective sleep quality, sleep latency, and sleep time, but an analysis of multiple comparison analysis with the general population group showed that the quality of sleep was worse compared to those that used the mat. In addition, sleep efficiency, sleep disorder, sleeping pills, and daytime dysfunction were found to be less than >0.05 in the three groups. Conclusions: These results suggest that if you ground your body to Earth during sleep, the secretion of cortisol will decrease night levels, sync more with the natural 24-hour circulation rhythm profile, and that when you sleep, sleep is better and pain and stress are associated with the study. While the preceding study cannot confirm that contact with the ground affects the quality of sleep, it suggests that it is relevant as shown in this paper.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.8 no.2
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• pp.296-305
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• 1998

A study was performed to evaluate an effect of toluene or ethanol pretreatment on the toluene metabolism. A slight liver damage in rats was induced by administration of 0.2 ml of toluene or 0.2 ml of 50% ethanol per 100 g of body weight intraperitoneally every other day for four weeks except the last day before sacrifice. One day before sacrifice, toluene was administered to rats pretreated ethanol or toluene and the control. Rats were sacrificed at the 1st, the 2nd, the 3rd and the 4th week after the first administration of xenobiotics mentioned above. Based on the histopathological findings, liver weight per body weight, serum alanine aminotransferase and hepatic glutathione content, toluene- or ethanol-pretreated groups showed the reversible liver injury. By the treatment of one dose of toluene, the contents of hippuric acid in urine was higher in the group pretreated with toluene or ethanol than control. The contents of cytochrome P-450, benzylalcohol dehydrogenase and benzaldehyde dehydrogenase activities were generally more increased in toluene- or ethanol-pretreated rats than control. $K_m$ values of the benzylalcohol dehydrogenase in pooled liver samples from toluene- and ethanol-pretreated groups were similar each other. $V_{max}$ values of toluene- or ethanol-pretreated group was higher than control. In conclusion, the toluene metabolism is accelerated in rats pretreated with toluene or ethanol.

• Journal of radiological science and technology
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• v.30 no.3
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• pp.227-236
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• 2007

We investigated the factors which influence the musculoskeletal symptoms in diagnostic medical sonographer. The Korean Society of Medical Sonographer conducted a survey through e-mail. Of the 400 subjects, 124 subjects responded(31%). The number of abdominal sonographer was 72(71.3%), obstetrics sonographer was 20(19.8%), echocardiographer was 9(8.9%) for effective 101 participant among themselves. According to the NIOSH diagnostic criteria, 86 subjects(85.1%) had musculoskeletal symptoms on their shoulders/neck, 73 subjects(72.3%) on their hands/wrists/arms/elbows, 44 subjects(43.6%) on their lower back. The factor of musculoskeletal symptoms were analyzed by the logistic regression analysis. The factors of symptoms for the hands/wrists/arms/ elbows were official autonomy, number of scans performed per week. The factors of symptoms for the shoulders/neck and the lower back were work break. However scan type were not observed as a significant factor. The study came to conclusion that many study subjects experienced musculoskeletal symptoms. These measures should be taken properly and promptly by the hospital's administrators.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.1
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• pp.61-69
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• 1997

To evaluate an effect of pathological liver damage on the toluene metabolism, the rate were induced acute liver damage with 3 times $CCl_4$ injection (0.1 ml of 50 % in olive oil/100 g body wt.) three days. In the present animal molel, the injection of toluene(0.3 ml of 50 % in olive oil) showed the more decreased urine hippuric acid throughout 24 hr in the liver damage induced animals($CCl_4$-pretreated rats) than normal group. The activities of hepatic aniline hydroxylase, benzylalcohol dehydrogenase and benzaldehyde dehydrogenase were significantly decreased in $CCl_4$-pretreated rats than the normal group at 24 hr after injection of toluene. Furthermore, the benzaldehyde dehydrogenase in pooled liver of $CCl_4$-pretreated rats showed similiar $K_m$ value, but showed the more decreased $V_{max}$ value compared with the normal group by the injection of toluene. These results suggest that the rats induced liver damage with $CCl_4$ may reduce the toluene metabolism.

• Journal of Preventive Medicine and Public Health
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• v.36 no.2
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• pp.137-146
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• 2003

Objectives : Impaired hearing is a prevalent occupational hazard, not only in industry, but also in the armed forces. In military life, noise has unusual characteristics, and constitutes a serious hazard to hearing. The aim of this study was to analyze the hearing threshold data in order to compare the hearing loss among shipyard workers, representing different workers, and a military service background. Methods : A cross-sectional audiological survey, combined with a questionnaire study, was conducted on a stratified random sample of 440 shipyard workers, with long-term exposure to noise. The employees were divided into four groups, according to their working and military service backgrounds, in relation to their exposure to noise. Results : As expected, the working and military noise exposure group (Group I) had significantly poorer hearing than the other groups. The high frequencies (2-8 kHz) showed the greatest difference in terms of poorer fearing in both ears. The prevalence of noise-induced hearing loss (NIHL) was highest in Group I. A logistic regression analysis was applied to determine the dependence of the NIHL in relation to age, smoking, drinking, working duration, ear protection, past history of ear diseases, and working and military sonics backgrounds, on the noise exposure The important factors found to be related to the NIHL, in relation to noise exposure were: age, work duration, and working and military service backgrounds. The adjusted odds ratio estimates for NIML in the right ear were 4.5 times greater (95% CI 1.7-11.6) for the military noise exposed group, and 7.9 times greater (95% CI 2.0-31.3) for the working noise exposed group than in the controls. The hearing thresholds at the pure-tone average and 4 kHz were significantly increased with age and work duration with both the working and military service backgrounds. Conclusions : From these results, specific preventive programs were planned, which should be assessed by epidemiological surveillance of the military noise exposed population.

• Journal of the Society of Disaster Information
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• v.17 no.3
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• pp.442-453
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• 2021

Purpose: The objective of this study is to suggest desirable direction of Korean accident investigation organization by analyzing the operation status and way of overseas developed countries' investigation agency. Method: To accomplish the objective of this study, we were examined four main characteristics of accident investigation agencies of the U.S., Japan, and Sweden, focusing on (1); the background of the establishment, (2);organizational structure, (3);major tasks and functions, (4); accident investigation procedures. Result: First, the purpose of its establishment and task is to prevent recurrence of disasters and accidents, at the same time, administrating and researching duties such as legal system, policy, recommending improvement and conducting scientific disaster-cause analysis to contribute safety for the government. Second, it is operated as an independent organization under the president, not belonging to the ministry, in order to enable fair investigation in an impartial position. Third, it has the authority to be recognized for its expertise in the results of investigation. In other words, it is operated as a permanent organization with professional personnel, and secures authority through the accident research with indepth investigation and high-quality recommendations. Conclusion: The overseas investigation agencies rapidly manage and coordinate their operational practices in order to resolve national requirements and social conflicts with fairness, accuracy and expertise in accident investigations. In order to prevent the recurrence of similar events, Korea needs to efficiently reconstruct its investigative functions distributed by each government department. In addition, institutional improvement is needed to make general adjustments at the national level, organize and operate control tower for when the accident has happened.

• Journal of agricultural medicine and community health
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• v.29 no.2
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• pp.303-314
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• 2004

Objectives: This study was carried out to assess exposure levels of organic dusts and ammonia in poultry farms in Korea. Methods: A total of six poultry farms were investigated. The farms were located in Namwon, Chonlabuk-do and in Kae-San, Chungchongbuk-do. This study consisted of a questionnaire and measuring organic dusts and ammonia. The questionnaire included the characteristics of the farms, work patterns and the tasks of the poultry farms. Results and Conclusions: The farmers raised the chickens 45 times a year and the average number of years in the poultry farm were eight years ranging from 2 to 12 years. They worked for seven days per week and the average hours spent caring the chickens are 6.3 hours per day. The duration of staying in the confinement buildings was 3.3 hours per day. The work time in summer was longest. The feed and the water supply systems were automatic and the control of ventilation windows used "winch curtain" was semiautomatic. They used mechanical ventilation system in winter and used dilution ventilation system in the other seasons. The geometric mean concentration of total and respirable dust sampled in the poultry confinement buildings was 4.0 mg/$m^3$and 0.9 mg/$m^3$ respectively. The ratio of respirable to total dusts range from 9 to 49 percent. There was no sample exceeding the criteria 10 mg/$m^3$ for total dust and 3 mg/$m^3$ for respirable dust in farms. The criteria have been recommended by Korean Ministry of Labor and American Conference of Governmental Industrial Hygienist. The personal respirable dusts measured during a circle work averaged geometric mean concentration 1.4 mg/$m^3$ Two personal samples were exceeded the threshold 3 mg/$m^3$. There was a positive relation between an index and the personal samples of respirable dusts($R^2$=0.98). The index is calculated by multipling the total number of chickens in the farm by the age of the chickens and then dividing by the volume of the confinement building. The geometric mean concentration of area and personal ammonia samples was 23.3 ppm and 22.2 ppm, respectively. Some of the ammonia samples, both area and personal samples, exceeded the short term exposure limit value 35 ppm.

• Tuberculosis and Respiratory Diseases
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• v.58 no.3
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• pp.230-242
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• 2005

Background : Spirometry should be compared with the normal predictive values obtained from the same population using the same procedures, because different ethnicity and different procedures are known to influence the spirometry results. This study was performed to obtain the normal predictive values of the Forced Vital Capacity(FVC), Forced Expiratory Volume in 1 Second($FEV_1$), Forced Expiratory Volume in 6 Seconds($FEV_6$), and $FEV_1/FVC$ for a representative Korean population. Methods : Based on the 2000 Population Census of the National Statistical Office of Korea, stratified random sampling was carried out to obtain representative samples of the Korean population. This study was performed as a part of the National Health and Nutrition Survey of Korea in 2001. The lung function was measured using the standardized methods and protocols recommended by the American Thoracic Society. Among those 4,816 subjects who had performed spirometry performed, there was a total of 1,212 nonsmokers (206 males and 1,006 females) with no significant history of respiratory diseases and symptoms, with clear chest X-rays, and with no significant exposure to respiratory hazards subjects. Their residence and age distribution was representative of the whole nation. Mixed effect models were examined based on the Akaike's information criteria in statistical analysis, and those variables common to both genders were analyzed by regression analysis to obtain the final equations. Results : The variables affecting the normal predicted values of the FVC and $FEV_6$ for males and females were $age^2$, height, and weight. The variables affecting the normal predicted values of the $FEV_1$ for males and females were $age^2$, and height. The variables affecting the normal predicted values of the $FEV_1/FVC$ for male and female were age and height. Conclusion : The predicted values of the FVC and $FEV_1$ was higher in this study than in other Korean or foreign studies, even though the difference was < 10%. When compared with those predicted values for Caucasian populations, the study results were actually comparable or higher, which might be due to the stricter criteria of the normal population and the systemic quality controls applied to the whole study procedures together with the rapid physical growth of the younger generations in Korea.