• 대한예방의학회:학술대회논문집
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• 1994.02a
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• pp.412-415
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• 1994

The fundamental assumption that thresholds exist for noncarcinogenic toxic effects of chemicals is reviewed; this assumption forms the basis for the no-observed-effect level/ safety-factor (NOEL/SF) approach to risk assessment for such effects. The origin and evolution of the NOEL/SF approach are traced, and its limitations are discussed. The recently proposed use of dose-response modeling to estimate a benchmark dose as a replacement for the NOEL is explained. The possibility of expanding dose-response modeling of non carcinogenic effects to include the estimation of assumed thresholds is discussed. A new method for conversion of quantitative toxic responses to a probability scale for risk assessment via dose-response modeling is outlined.

• Journal of Society of Preventive Korean Medicine
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• v.11 no.2
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• pp.133-139
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• 2007

In the study of Stress-Control by Qigong Program, the results were as follows : In modern society, many stress factors affect the human organism, altering and chipping away at our nervous, endocrine, locomotor, reproductive, digestive, respiratory, circulatory and immune systems. The beneficial effects of Qigong can help us to restore our equilibrium and enhance our quality of life. This study was performed to investigate the effect of Qigong on stress and psychological symptoms. Twenty-two subjects were trained Qigong Program a week for 8 weeks. The stress index of subjects and psychosomatic symptoms was compared before and after Qigong Program and was significantly decreased after Qigong training. It means that the stress index and psychosomatic symptoms were improved by Qigong training.

• 대한예방의학회:학술대회논문집
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• 2002.10a
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• pp.195-196
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• 2002

• 대한예방의학회:학술대회논문집
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• 2002.10a
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• pp.208-209
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• 2002

• 대한예방의학회:학술대회논문집
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• 2002.10a
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• pp.292-293
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• 2002

• Journal of Korean Institute of Industrial Engineers
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• v.36 no.2
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• pp.108-116
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• 2010

The maintenance of a deteriorating system is often imperfect. Previous studies have shown that the imperfect preventive maintenance (PM) can reduce the wear out and aging effects of deteriorating systems to a certain level between the conditions of as good as new and as bad as old. In this paper, we employ the concept of the improvement factor in investigating two optimal PM policies; failure limit policy and periodic PM policy. We redefine the improvement factor model as a function of the cost of PM, using this concept, we derive the conditions of optimal PM policies and formulate expressions to compute the expected cost rate. Based on this information, the determination of the maintenance policies which minimize the cost rate is examined. Numerical examples for the Weibull distribution case are also given.

• Journal of Preventive Medicine and Public Health
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• v.17 no.1
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• pp.217-221
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• 1984

In order to estimate interfering effects of mercury and lead on biochemical oxygen demand (BOD), BOD in 18 effluent samples were measured under three different concentrations of mercury and lead. The results obtained were as follows: 1. Biochemical oxygen demand(BOD) was decreased under the presence of mercury and lead, with parallel correlation of mercury concentration. 2. High correlations were noted between original BOD concentration and decreasing amount of BOD when concentrations of mercury or lead were increased. 3. When the lead concentration was high, the close correlation was observed between total organic carbon(TOC) and decreasing amount of BOD. 4. There was a negative correlation between TOC/BOD ratio and decreasing amount of BOD when the mercury concentrations were high.

• Journal of Preventive Medicine and Public Health
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• v.17 no.1
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• pp.245-250
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• 1984

Reciprocal exchanges of DNA in sister chromatids (SCEs) are induced by various carcinogens and mutagens, although the quantitative relationship between the number of mutations and SCEs induced varies among chemicals. Nevertheless, the analysis of SCEs production by various agents often proposed as a sensitive and quantitative assay for mutagenicity and cytotoxicity. Mercury, even if which has no evidences for mutagenicity and carcinogenicity, is reported to exert some cytotoxic effects, such as chromosomal aberrations or bad influences to ovulation and reproduction in experimental animals, etc.. In this study, tests for sister chromatid exchanges have been carried out on normal human lymphocytes in whole blood culture to add mercury chloride ($HgCl_2$) or methylmercury chloride ($CH_3\;HgCl$) for 72 hr. The results indicate the dose-dependent relationship between the frequencies of SCEs and the concentrations of $HgCl_2,\;CH_{3}HgCl$ and 5-bromo-2'-deoxyuridine (BrdU). Lymphocyte proliferation has depressed in the higher concentration of mercury.

• Journal of Ginseng Research
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• v.13 no.1
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• pp.5-7
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• 1989

The objective of this study was to investigate the preventive effect of ginseng on acetaldehyde-induced acute toxicity in mice . Compared to the control group, treatment with acetaldehyde inhibited the hepatic cytosolic xanthine oxidise activity with increase in dose. The inhibition of enzyme activity was not changed after dialysis. Pretreatment with ginseng butanol fraction prevented the inhibition of enzyme activity by acetaldehyde. In conjunction with the our previous results (Yakhak Hoeji, 29, 18 (1985)), these results suggest that the most likely mechanism for the observed preventive effects of ginseng against the acetaldehyde-induced acute toxicity may be the decrease hepatic acetaldehyde level.

• Toxicological Research
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• v.12 no.2
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• pp.283-288
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• 1996

This study was performed to investigate the effects of chitosan on the lead poisoning in rats. For this experiment, 15 male Sprague-Dawley rats were used. The experimental groups were divided into five: Control (250 mg/kg lead), Group I (250 mg/kg lead+1% chitosan), Group II (250 mg/kg lead+2% chitosan), Group III(250 mg/kg lead+4% chitosan), Group IV (250 mg/kg lead+8% chitosan). The results were as follows; 1. The lead concentration in the liver showed 3.924~10.217 mg/kg in control group, but treated group was inclined to decrease during the experiment period (P<0.05). 2. The lead concentration in the kidney showed 23.268~31.315 mg/kg in control group, but Experimental group showed 3.765~9.725 mg/kg (Group I), 34.60~9.115 mg/kg (Group II), 3.549~8.816 mg /kg (Group III), 3.502~8.532 mg/kg (Group IV) resectively, also, Experimental group was inclined to decrease compared to control group (P