• KEPCO Journal on Electric Power and Energy
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• v.8 no.2
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• pp.111-118
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• 2022

SF₆ is used as an insulating gas because of its excellent electrical insulation properties, non-toxicity, and non-inflammability. On the other hand, the global warming potential of SF₆ is 23,900 times higher than that of CO₂. The Korea electric power cooperation (KEPCO) is responsible for 80% of the domestic SF₆ usage, and approximately 6,000 tons are currently charged in electrical and power facilities. KEPCO will gradually replace the insulating gas with SF₆-free gas from 2023. SF₆ decomposition facilities are required because more than 60 tons of SF₆ will need to be disposed of annually from existing equipment. This study developed a novel decomposition and pollution control system that can process 60 tons of SF₆ per year. This facility can decompose more than 97.7% of SF₆, with the emissions of hazardous and toxic materials below the legal limit.

• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.184-191
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• 2016

In recent years, there are a number of studies that have been carried out to explore the alternative for Mineral Oil (MO) as dielectric insulating fluid in transformers due to the increasing tight regulation on safety and environment. Vegetable oils have been identified as suitable candidate since it is biodegradable, non-toxic and high flash/fire points which ensure more in-service safety. Among the types of vegetable oils considered for transformers application are Palm Oil (PO) and Coconut Oil (CO). This paper presents an experimental study on the lightning breakdown voltages of PO and CO under non-uniform electric field based on needle-sphere electrodes configuration at 3 small gap distances. The type of PO used in this study is Refined Bleached and Deodorized Palm Oil (RBDPO) Olein. The main focus of this study is to examine the lightning breakdown performance of RBDPO and CO under different test conditions and assess its suitability as dielectric insulating fluid in transformers. The effect of voltage polarities (positive and negative) and testing methods (rising-voltage, up-and-down and multiple-voltage) were investigated. The data obtained from all tests were analysed by Weibull distribution in order to determine the withstand voltages for each type of oils. It was found that the breakdown voltages of RBDPO and CO are comparable with MO under positive lightning impulse. Under negative lightning impulse, the breakdown voltage of MO is slightly higher than RBDPO and CO. There is no significant effect of testing methods and voltage polarities on lightning breakdown voltages of RBDPO and CO. Based on the statistical analysis, it is found that the breakdown voltages of RBDPO and CO at 1% probability are slightly lower than MO.

• Journal of Environmental Science International
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• v.20 no.4
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• pp.457-463
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• 2011

This study was carried out to compare the toxicity of nano and micrometer particles with Cu and Zn on soil microbial community and metal uptake of buck wheat. In microcosm system, soil was incubated for 14 days after soil aliquots were artificially contaminated with 1,000 mg/kg Cu, Zn nano and micro particles, respectively. After then, buck wheat was planted in incubating soils and non incubating soils. After 14 days, we compared bioaccumulation of metal, and microbial carbon substrate utilization patterns between incubating soils and non-incubating soils. The enrichment factor (EF) values of incubating samples were greater than non-incubating soils. Dehydrogenase activity had been inhibited by Cu and Zn nanoparticles in non-incubating soil, as well as it had been inhibited by Zn micro particles in incubating soils. Results of biolog test, it was not significant different between nano particles and micro particles. It cannot be generalized that nanoparticles of metal are always more toxic to soil microbial activity and diversity than micrometer-sized particles and the toxicity needs to be assessed on a case-by-case basis.

• Korean Journal of Medicinal Crop Science
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• v.19 no.4
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• pp.287-299
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• 2011

Pharmacological effects of Panax ginseng have been demonstrated in cardiovascular system, endocrine secretion and immune system, together with antitumor, anti-stress and anti-oxidant activities. Modern scientific data show protective effect of ginseng against bone marrow cell death, increased survival rate of experimental animals, recovery of hematopoietic injury, immunopotentiation, reduction of damaged intestinal epithelial cells, inhibition of mutagenesis and effective protection against testicular damages, caused by radiation exposure. And also, ginseng acts in indirect fashion to protect radical processes by inhibition of initiation of free radical processes and thus reduces the radiation damages. The research has made much progress, but still insufficient to fully uncover the action mechanism of ginseng components on the molecule level. This review provides the usefulness of natural product, showing no toxic effects, as an radioprotective agent. Furthermore, the further clinical trials on radioprotection of ginseng need to be highly done to clarify its scientific application. The effective components of ginseng has been known as ginsenosides. Considering that each of these ginsenosides has pharmacological effect, it seems likely that non-saponin components might have radioprotective effects superior to those of ginsenosides, suggesting its active ingredients to be non-saponin series. These results also show that the combined effects of saponin and non-saponin components play an important role in the radioprotective effects of ginseng.

• Korean Journal of Community Nutrition
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• v.9 no.3
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• pp.303-314
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• 2004

We studied daily micronutrient intake from vitamin-mineral supplements, health-related life style, clinical case of diseases and food frequency of the Korean middle-aged (40-59 yr, n = 404) to compare the characteristics of non-user (n = 270) and user (n = 134) of vitamin-mineral supplements. Rate of supplement use of the middle-aged was 33.2% and there was significant difference in education level (p = 0.0084) and family income (p = 0.0476) of user and nonuser. Smoking habit (p = 0.0844) and drinking frequency (p = 0.0606) tended to be lower in a supplement user than a non-user. The medical history of a case was significantly higher in users (67.9%) than in non-users (44.4%) (p = 0.001), which suggests that medical history is one of the important motivations of supplement use. Supplement users had the medical history of digestive disease (34.1%), anemia (11.0%) and hypertension (9.9%) in order. Vitamin C was the most frequently supplemented nutrient (81.3%) among vitamin-mineral supplement, and the next orders were vitamins E (73.1%), B$_2$(68.7%) and B$_{6}$ (60.4%). Mean intakes of vitamin B$_1$, iron, selenium, vitamin E, and vitamin C from supplement was 4,260%, 4,030%, 1,660% and 1,330% of RDA, respectively. The supplement users tended to consume most food items including milk ＆ milk products (p ＜ 0.01), rice (p ＜ 0.01), grains (p ＜ 0.05) and cookies (p ＜ 0.01) less frequently than non-users. Conclusively, nutrient intake of vitamin B$_1$, iron, selenium, vitamin E, and vitamin C from supplement was excessively high compared to RDA. We suggest that the toxic effect of excessive supplementation should he informed to supplement user and nutritional education should be focused on the optimal supplement dose.e.

• Economic and Environmental Geology
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• v.30 no.6
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• pp.587-601
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• 1997

This study had three purposes: (1) to investigate the enrichment levels and dispersion patterns of potentially toxic elements in the rock-soil-plant system; (2) to evaluate the uptake ratios of heavy metals from soils into plants and (3) to assess the chemical speciation of heavy metals in soils. Rock, surface soil and plant samples were collected in the Boeun area underlain by black shales of the Okchon Zone. These samples were analyzed for multi-elements using INAA, ICP-AES and AAS. The maximum abundance of U in black shales is 16 mg/kg and radioactivity counts up to 300 cpm. In particular, Mo, V, Ba, Cd, Pb and U are enriched in black shales. Most of soils derived from black shales show high concentrations of U, As, Mo, Ba, Cu, Cd, Pb, Zn and mean concentrations of As and Mo in soils (20 mg/kg of As and 6.6 mg/kg of Mo) are higher than the permissible level suggested by Kloke (1979). Enrichment index values of soils are calculated and higher than 1.0 in the black shale area with the highest value of 6.4. Mean concentration of Cd in plants is higher than those of Cu, Pb and Zn. The concentration of Cd in plant species decreases in the order of Chinese cabbage > red pepper > soybean=sesame > rice stalk > com > rice grain. The biological absorption coefficients (BAC) in plants are in the order of Cd > Zn=Cu > Pb, which suggests that Cd is more bioavailable to plants than Cu, Pb and Zn. From the results of sequential extraction analysis of soils, relatively high proportion of Cu, Pb and Zn are present as residual fractions whereas that of Cd as non-residual fractions. Cadmuim occurs predominantly as exchangeable/water-acid soluble phase in soils, and Cd is more mobile and bioavailable than Cu, Pb and Zn.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.1
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• pp.33-40
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• 2012

This paper proposes a method to implement biological early warning systems(BEWS). This system generates periodically data event using a monitoring daemon and it extracts the feature parameters from this data sets. The feature parameters are derived with 6 variables, x/y coordinates, distance, absolute distance, angle, and fractal dimension. Specially by using the fractal dimension theory, the proposed algorithm define the input features represent the organism characteristics in non-toxic or toxic environment. And to find a moderate algorithm for learning the extracted feature data, the system uses an extended learning algorithm(UChoo) popularly used in machine learning. And this algorithm includes a learning method with the extended data expression to overcome the BEWS environment which the feature sets added periodically by a monitoring daemon. In this algorithm, decision tree classifier define class distribution information using the weight parameter in the extended data expression. Experimental results show that the proposed BEWS is available for environmental toxicity detection.

• YAKHAK HOEJI
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• v.43 no.2
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• pp.180-197
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• 1999

Acute and subacute oral toxicity of $HELIKIT^{TM}$ ($^{13}C-urea$) were carried out in Sprague-Dawley rats of both sex. The toxicity of $HELIKIT^{TM}$ was compared with urea($^{12}C-urea$ which is used for control). In acute toxicity studies, we daily examined number of deaths, clinical signs, body weights and pathological examination for 14 days after single oral administration of HELIKIT or urea($^{12}C-urea$) at a dose of 5000 mg/kg. The subacute oral toxicity was investigated in Sprague-Dawley rats treated with $HELIKIT^{TM}$ at a dose of 40, 200 and 1,000 mg/kg/day or $^{12}C-urea$ at a dose of 1,000 mg/kg/day for 4 weeks. In acute toxicity studies, $HELIKIT^{TM}$ and urea did not show any toxic effect in rats and oral LD50 value was over 5,000 mg/kg rats. In subacute toxicity studies, no death occured and no drug-related changes were found in clinical observations; body weight, food consumption, opthalmoscopy. auditory test, urinalysis, hematology, blood chemistry, gross pathological examination or organ weight between $HELIKIT^{TM}$, urea and control groups. In histopathological examinations, the slight thickening of mucosa of the limiting ridge in the stomach was noted in the animals treated with $HELIKIT^{TM}$ at a dose of 1,000 mg/kg/day and also the changes in urea group at a dose of 1,000 mg/kg/day was found, but all of these changes in the changes in ures group at a dose of 1,000 mg/kg/days was found, but all of these changes in the stomach regressed after withdrawal of the test article for 2 weeks and reversibility of the effect was revealed. These results indicate that the non toxic dose level of $HELIKIT^{TM}$ was 1,000 mg/kg/day in the 4 weeks-repeated dose study, suggesting that the substitution of $^{13}C$ for carbon in urea molecule has no effect on the toxicity of urea and changes in stomach are reversible.

• Korean Journal of Clinical Pharmacy
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• v.23 no.4
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• pp.344-364
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• 2013

Background: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are immune-complex-mediated hypersensitivity reactions that predominantly involve skin and mucous membranes. Despite the low incidence, both are considered medical emergencies as the mortality rate has been estimated at 30-50%. Although as many as half of cases are idiopathic, several drugs have been implicated as main cause of SJS/TEN. This review therefore aimed to identify drugs that were potentially associated with SJS/TEN and compare the relative risk of the medications. Method: A comprehensive search was performed using MEDLINE, EMBASE and 5 Korean databases. We defined study drugs as non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics, antiepileptics, and allopurinol. Only epidemiologic studies investigating associations between the above drugs and drug-induced SJS/TEN were included. Two reviewers independently selected and evaluated candidate papers and extracted odds ratios or incidence rates. Meta-analysis was performed only for drugs that were reported from 4 or more studies. Results: We found 8 case-control studies, 3 cohort studies and 1 RCT. The ranges of adjusted ORs were 0.6-34.0 for NSAIDs, 1.6-302.0 for antiepileptics, 0.3-10.0 for antibiotics and 1.0-187.0 for allopurinol. The drug with the highest incidence of SJS/TEN was carbamazepine (40 persons/1,000 DDD). Conclusion: Finally, the risk was highest in first 8 weeks after onset of treatment in all drugs.

• Journal of Pharmacopuncture
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• v.5 no.2
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• pp.40-51
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• 2002

Objectives : The purpose of this study was to investigate the effect of Bee Venom on the lipopolysaccharide-induced expression phospholipase $A_2$, cyclooxygenase-2 and inducible nitrogen oxide synthase, and the generation of arachidonic acid, prostaglandin D2 and E2 in RAW 264.7 cells, a murine macrophage cell line. Methods : The expression of phospholipase $A_2$, cyclooxygenase and inducible nitrogen oxide synthase was determined by western blotting with corresponding antibodies, and the generation of arachidonic acid, prostaglandin $D_2$ and $E_2$ was assayed by ELISA method in RAW 264.7 cells. The non-toxic concentrations (0.1 to $5\;{\mu}g/ml$) of bee venom determined by MTT assay, were used in this study. Results : 1. Bee venom inhibited lipopolysaccharide-induced expression of phospholipase $A_2$ in a dose dependent manner after 48 hours treatment. 2. Bee venom inhibited lipopolysaccharide-induced expression of cyclooxygenase-2 in a dose dependent manner after 24 and 48 hours treatment. 3. Bee venom inhibited lipopolysaccharide-induced expression of inducible nitrogen oxidesynthase in a dose dependent manner after 48 hours treatment. 4. The generation of arachidonic acid, prostaglandin $D_2$ and $E_2$ was not much affected by the treatment of bee venom on the lipopolysaccharide-induced generation of arachidonic acid, prostaglandin $D_2$ and $E_2$ in RAW 264.7 cells.