• Journal of Ginseng Research
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• 제33권4호
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• pp.355-360
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• 2009

Phenanthrene ($C_{14}H_{10}$) is a polycyclic aromatic hydrocarbon with three aromatic rings, and it can be produced by incomplete combustion of fossil fuels. Comet assay was used to examine the oxidative DNA damage of lymphocytes by phenanthrene and to measure the suppressive effects of ginseng extract on the DNA damage in this investigation. The in vitro oxidative DNA damage by phenanthrene increased in a dose-dependent manner in the lymphocyte. However, the DNA damage was significantly inhibited by ascorbate. Moreover, pretreatment, cotreatment and posttreatment with ginseng extract enhanced lymphocyte resistance to the phenanthrene-induced DNA damage. Phenanthrene enhanced the generation of intracellular reactive oxygen species, and the elevated reactive oxygen species level was reduced by treatment with ginseng extract.

• Environmental Analysis Health and Toxicology
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• 제16권1호
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• pp.17-20
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• 2001

The alkaline comet assay, employing a single-cell gel electrophoresis(SCGE), is a rapid, simple and sensitive technique for visualizing and measuring DNA damage leading to strand breakage in individual mammalian cells. The protecting effect of pretreatment with vitamin C and cysteine on the DNA damage of gamma ray was investigated in mice splenic lymphocytes. Vitamin C and cysteine were administered orally for five consecutive days before irradiation. Four week old ICR male mice were irradiated wish 3.5Gy of γ-radiation and were sacrificed 3 days later. Spleens were taken for DNA damage examination by Comet assay and the tail moments of DNA single -strand breaks in tole splenic lymphocytes were evaluated. The results show that pretreatment with vitamin C and cysteine were effective in protecting against DNA damage by gamma ray. Administration of antioxidants like vitamin C and cysteine to mice before irradiation was effective in reducing the tail moment of splenic lymphocytes DNA.

• 한국전자파학회논문지
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• 제11권1호
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• pp.93-101
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• 2000

본 논문에서는 국내환경에서 비정지궤도 위성인 COMETS의 Ka 대역 비콘 신호를 측정하였고 측정된 데이터를 이용하여 시간, 거리 및 고도각의 변화에 따른 전파전파특성에 대하여 분석하였다. 분석 결과 Clear sky에서의 거리 변화에 따른 전파전파특성은 자유공간손실이 중요한 영향을 끼침을 알 수 있었으며, COMETS 위성은 고도각이 40도 이상에서 관측되므로 고도각이 신호에 미치는 영향은 거의 나타나지 않았다.

• 천문학회보
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• 제36권1호
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• pp.41.2-41.2
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• 2011

P/2010 A2, a main-belt asteroid having comet-like dust trail was discovered in January 2010, but the origin of the trail is controversial. Moreno et al. (2010) reported water-ice sublimation as a mechanism for the comet-like activity, whereas other researches (Jewitt et al. 2010; Snodgrass et al. 2010) stated that impact collision contributed to the dust trail. For asteroids are categorized based on spectral shape, optical observation using different color filters makes it possible to determine the taxonomic type of P/2010 A2 nucleus, thus gives an answer to the question of activation mechanism of the object. In this presentation, we report multiband observation of P/2010 A2 in January and March 2010 with 1-meter telescope of Ishigaki-Jima Astronomical Observatory. We employed three broadband filters of g', Rc, and Ic. In this presentation, we focus on the data acquisition, the reduction and the derivation of the reflectance spectrum of debris in the trail. Finally we discuss the potential cause of dust ejection from this asteroid.

• Journal of Astronomy and Space Sciences
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• 제41권1호
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• pp.35-42
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• 2024

Sungrazing comets, known for their proximity to the Sun, are traditionally classified into broad groups like Kreutz, Marsden, Kracht, Meyer, and non-group comets. While existing methods successfully categorize these groups, finer distinctions within the Kreutz subgroup remain a challenge. In this study, we introduce an automated classification technique using the densitybased spatial clustering of applications with noise (DBSCAN) algorithm to categorize sungrazing comets. Our method extends traditional classifications by finely categorizing the Kreutz subgroup into four distinct subgroups based on a comprehensive range of orbital parameters, providing critical insights into the origins and dynamics of these comets. Corroborative analyses validate the accuracy and effectiveness of our method, offering a more efficient framework for understanding the categorization of sungrazing comets.

• 한국식품위생안전성학회:학술대회논문집
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• 한국식품위생안전성학회 2002년도 춘계학술발표대회 및 심포지움
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• pp.211-214
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• 2002

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 1999년도 한국우주과학회보 제8권2호
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• pp.49-49
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• 1999

No Abstract, See Full Text

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 1998년도 한국우주과학회보 제7권1호
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• pp.25.1-25
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• 1998

No Abstract.See Full-text

• 한국영양학회:학술대회논문집
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• 한국영양학회 2001년도 추계학술대회 초록
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• pp.49-49
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• 2001

• 대한생식의학회:학술대회논문집
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• 대한생식의학회 2007년도 제53차 추계학술대회 초록집
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• pp.105-105
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• 2007