• YAKHAK HOEJI
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• v.46 no.3
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• pp.208-212
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• 2002

Dehydroevodiamine HCl (DHED), which is a component separated from Evodia rutaecarpa Bentham, has novel anticholinesterase and antiamnesic activities in the scopolamine-induced amnesia model. Several studies suggest that DHED might be an effective drug for the Alzheimer's disease and the vascular type of dementia. In order to evaluate the mutagenic potential of DHED, Salmonella typhimurium reversion assay, chromosomal aberration test on Chinese hamster lung cells, in vivo micronucleus assay using mouse bone marrow cells, and comet assay were performed. DHED did not increase the number of revertant in the reverse mutation test using Salmonella typhimurium TA1535, TA1537, TA98, TA100. DHED HCl, at concentration of 5 and 10 $\mu\textrm{g}$/mι, increased the number of chromosome aberrated Chinese hamster lung cells with 5 and 10％, respectively. In mouse micronucleus test, no significant increase in the occurrence of micronucleated polychromatic erythrocyte was observed in ICR mice orally administered with DHED. DHED was tested for ability to induce genotoxic effect in L5178Y cells (mouse lymphoma cells) using the single cell gel electrophoresis assay (comet assay). In comet assay, tail moment did not increase in L5178Y cells treated with 10, 100, 300 $\mu$M DHED.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.77-84
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• 2000

Although ferric sulfate has been proposed as an alternative to formocresol in pulpotomy treatment in primary teeth, it has been given little concern regarding its cytotoxicity and mutagenicity. In the present study, we assessed the in vitro genotoxic effect of a ferric sulfate on human gingival fibroblast cell line (HGF-1). DNA damage was evaluated using comet assay (single cell alkaline gel electrophoresis) and obtained the results as follows: 1. A dose-response relationship was found between ferric sulfate concentrations (0 to 5mM) and DNA damages. 2. Above the concentration of 0.1mM, DNA damage was significantly increased than those of the control (p<0.05). 2. At the fixed concentration of 0.05mM, no significant difference was found between exposure time and DNA damage. These findings suggest that ferric sulfate as a pulpotomy agent can induce DNA damage in human gingival fibroblasts.

• Korean Journal of Organic Agriculture
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• v.10 no.1
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• pp.65-74
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• 2002

The results of the experiment about the effect of the length of electrical stimulation treatment time on the yield components and NO$_3$ content in edible parts of 2 cherry type radishes(Raphanus salivas L.) were like followings. 1. The 2 hours electrical stimulation promoted the length of leaf and the enlargement of the root diameter of 'Comet' and 'Sakuranbo' cultivars, and their root diameters were increased by 14.7% and 12.8% respectively than that of the control. 2, The plot which showed the highest root fresh weight was the 2 hours stimulation plot in 'Comet' and 8 hours stimulation plot in 'Sakuranbo', and these results were approximately 39% higher than that of the control. 3. All of the electrically stimulated plots of 'Comet' and 'Sakuranbo' showed higher NO$^{[-10]}$ $_3$content in roots than the control. And the amount of NO$^{[-10]}$ 3 in their roots showed a remarkable positive correlation with the root diameter, the root fresh weight and the total fresh weight.

• Journal of KIISE:Software and Applications
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• v.34 no.8
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• pp.721-730
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• 2007

UML (Unified Modeling Language) is widely used to analyze and design target software. Developers also implement the target software based on the UML artifacts. However, it is difficult to validate whether the artifacts are generated to correspond to the modeling guidelines because the guidelines for UML modeling are described in natural language. This paper discusses rule based model checker focused on whether models are designed according to modeling methodology. We propose rules and their own checker, named GARDIAN, for UML model validation. The checkers are designed for COMET method for the real-time embedded system. We illustrate our checkers using Intelligent Robot system to validate our approach.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.159-159
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• 2003

Comet assay is a potential monitoring tool because DNA strand breakage may be produced by a wide range of agents. The comet assay, also called the single-cell gell electrophoresis (SCGE) assay, is rapid and sensitive method for the detection of DNA damage in cells. This study was performed for the identification of DNA damage in the cells from flounders and clams exposed to PAHs. As a control experiments, flounder and clam cells were exposed to $H_2O$$_2$. The cells exposed to $H_2O$$_2$ were displayed a typical nuclei movement DNA damage of cells were significantly increased when the isolated cells from the blood of flounders and the tissue of clams were in vitro exposed to the different concentrations (5, 10, 50, 100 ppb) of five kinds of PAHs (benzo[a]pyrene, pyrene, fluoranthene, anthrancene, and phenanthrene). For the in vivo test, flounders and clams were exposed to the different concentrations of BaP for 4 days. The results showed that DNA strand breakage was effected by the concentration of BaP and the duration of exposure. In high concentration of BaP, the mean tail lengths of nuclei was longer than it In low concentration, while the mean size of head DNA decreased. In this research, both in vitro and in vivo genotoxicity of PAHs could be biomonitored by the comet assay. Especially, clams and flounders seem to be useful as materials for monitoring genotoxic damage by comet assay.

• Journal of the Korean Society of Food Culture
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• v.19 no.2
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• pp.129-138
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• 2004

The changes in DNA damage were investigated during storage after irradiation. Beef, pork and chicken were irradiated at 1.0, 3.0 and 5.0 kGy and stored for 6 months at $-20^{\circ}C$. The comet assay was applied to the sample muscles at the beginning of irradiation and at the end of storage. Muscles were isolated, sliced, and the suspended cells were embedded in an agarose layer. After lysis of the cells, they were electrophoresed for 2 min. and then stained. DNA fragmentation in tissues caused by irradiation was quantified as tail length and tail moment (tail length ${\times}$ % DNA in tail) by comet image analyzing system. Right after irradiation, the differences in tail length between unirradiated and irradiated muscles were significant(p<0.05) in beef, pork and chicken. With increasing the increasing doses, statistically significant longer extension of the DNA from the nucleus toward anode was observed. Similarly even 6 months after irradiation, all the irradiated muscles significantly showed longer tail length than the unirradiated controls. The results represented as tail moment showed similar tendency to those of tail length, but the latter parameter was more sensitive than the former. These results indicate that the comet assay could be one of the simple methods of detecting irradiated muscles. Moreover, this method suggest that using comet assay, we were able to detect DNA damage differences even after 6 months after irradiation.

• Publications of The Korean Astronomical Society
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• v.10 no.1
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• pp.1-14
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• 1995

We observed impact spots on Jupiter which were formed by the collision with fragments of Shoemaker-Levy 9 comet during the period from 17 July to 13 August, by using the SNU 61cm reflector combined with CCD camera and DBVRI filters. In order to get more clear image of impact spots, the observed data were processed by the unsharp masking method, high-pass filtering method and Richardson-Lucy algorithm after the basic processing through IRAF package. The sizes of impact spots range from 2000km to 1000km, and from this size, the original size of comet fragments before collision with Jupiter is estimated to be less than ${\sim}3km$. From the observed rotating rate of impact spots, the rotational period of Jupiter is determined as $9^h$ $56^m$ $32^s$ at the southern latitude of $47^{\circ}{\sim}49^{\circ}$.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.53.2-53.2
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• 2010

A Jupiter-family comet, 17P/Holmes, suddenly underwent a spectacular outburst on 2007 October 23, about 173 days after the perihelion passage. There has been no more outstanding comet outburst than the 17P/Holmes event since the beginning of modern astronomical observations. However, little is known about the activity of the comet before the outburst because of the accidental event. We found that 17P/Holmes appeared in the AKARI all sky survey data. It was taken on 2007 August 23, 112 days after the perihelion passage and 61 days before the outburst. The 9 micron images shows obvious coma and tail. We study the dust production rate from these images and evaluate the fractional active area. We compare these results with those of data after the outburst, and discuss the aftermass.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2002.11a
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• pp.145-153
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• 2002

유해 화학 물질류에 의해 오염된 해양 환경 시료의 환경독성 수준을 평가하기 위하여 다양한 화학물질에 대해 민감성이 우수한 생물학적 독성평가기법을 개발 하고자하였다. 지속성 유기오염 물질 중 다환 방향 족 탄화수소(PAHs)를 처리한 광어(Conger myriaster)와 개조개(Saxidomus pupurata)의 DNA 손상정도를 single cell gel electrophoresis assay(comet assay)를 통해 분석하였다. PAHs 중 광양만에서 높은 농도로 검출되는 benzo(a)pyrene을 농도별(0, 10, 50, 100 ppb)로 처리한 후 2일과 4일에 광어의 혈액세포와 개조개의 근육세포를 채취해 comet assay를 실시하였다. benso(a)pyrene에 대한 DNA 손상정도를 처리된 농도와 생물종에 따라 다르게 나타났는데 광어의 혈액세포는 2일에 가장 DNA 손상정도가 높았고, 4일에는 회복되는 경향을 나타냈다. 개조개의 근육세포는 시간이 지나면서 DNA 손상정도가 증가하는 경향을 보였다. 이와 같은 결과는 comet assay 기법이 유해 화학물질로 오염된 해양생물 종의 환경독성을 검색하는 유용한 수단이 될 수 있음을 보여준다.

• Publications of The Korean Astronomical Society
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• v.22 no.4
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• pp.183-187
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• 2007

The detection and measurement of faint features in cometary image is generally troublesome due to the high value of the ratio of the brightness of the nucleus to the tail, the large size and low surface brightness of the coma and tail and the disturbing presence of field stars trails. The image processing is based on background removal by median filtering. Sample results are shown for the case study of comet 73P/Schwassmann-Wachmann 3.