• Title/Summary/Keyword: Bowen 선

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Spectroscopic Observation of AG Peg and Efficiency Changes of Bowen Fluorescence Mechanism (AG Peg의 분광 관측과 Bowen 형광 기작의 효율 변화)

  • Hyung, Siek;Lee, Seong-Jae;Lee, Kang Hwan
    • Journal of the Korean earth science society
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    • v.38 no.6
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    • pp.405-420
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    • 2017
  • We investigated the H I, He II and O III emission lines of the symbiotic star AG Peg, using the spectroscopic data secured at different phases in three periods at the Lick Observatory. We measured FWHM and the intensity of six O III Bowen lines and studied the efficiency of fluorescence mechanism. The mean FWHM of O III normal and Bowen lines observed during three time periods did not make much difference, while Bowen line intensities are about 4.0 times higher than the normal lines. Comparing the predicted and the observed ratios, we found that the observed intensities are higher than predicted intensities, except for O III ${\lambda}$ 3759.87. The O III ${\lambda}$ 3791.26 and 3754.67 intensity ratios observed only in 2001 are in good agreement with the predictions by Saraph and Seaton (1980). We obtained the Bowen efficiency parameter (R)=0.47 for 2002, but we could not find R for the other two periods of time. Because of this, based on the 2002 efficiency result, we calculated the intensity ratio of O III normal and Bowen lines relative to He II ${\lambda}$ 4685.68 and derive the efficiency variation with time period. The result showed that the efficiency is the highest in 1998 and the lowest in 2001. We conclude that the efficiencies with phase are caused by the electron temperature changes in the ionized gas. The efficiencies of AG Peg are likely to increase along with electron temperature. Our analysis results may be useful in understanding the physical conditions of the ionized shell in symbiotic star and the intensity ratio and efficiency variation.

Various Skin Tumors Originating from Disseminated Superficial Actinic Porokeratosis (파종얕은광선땀구멍각화증에서 발생한 다양한 피부종양)

  • Jeong, Hae Bong;Jo, Jeong Won;Shin, Young Bin;Kim, Chi Yeon
    • Korean journal of dermatology
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    • v.56 no.10
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    • pp.628-630
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    • 2018
  • Disseminated superficial actinic porokeratosis (DSAP) is a rare keratinization disorder. It is histopathologically characterized by the presence of coronoid lamellae and clinically by lesions showing central atrophy with elevated borders. Squamous cell carcinoma originating in the classical Mibelli subtype of porokeratosis is well-documented; however, few reports have described squamous cell carcinoma in DSAP lesions. We report the case of a 76-year-old woman with DSAP who developed Bowen's disease, actinic keratosis, and keratoacanthoma on her face.

Effects of Tomatoes and Lycopene on Prostate Cancer Prevention and Treatment (토마토와 라이코펜이 전립선암의 예방과 치료에 미치는 영향)

  • ;Phyllis E. Bowen
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.33 no.2
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    • pp.455-462
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    • 2004
  • Prostate cancer is a leading cause of cancer death in American men and evidences point to significant life style/diet components as risk factors for its development or prevention. Two large cohort studies have identified the consumption of tomatoes or high Plasma levels of Iycopene as associated with reduced risk. A number of other substances such as quercetin, phytoene, phytofluene, cyclolycopene, salicylates and tomatine in tomato besides lycopene could have anticancer activity and may be acting synergistically with lycopene. Lycopene at almost physiologically feasible concentrations, reduces cell viability by cell cycle arrest and apoptosis and modulates the cyclin pathways as well as increasing intercellular communication. However, it is not clear whether lycopene or its oxidation products are more bioactive. Tomato product supplementation results in plasma accumulation of phytoene, Phytofluene, the lycopene oxidation product, and cyclolycopene at significant concentrations and lycopene supplementation, either as a tomato product or as beadlets, results in maximal mean plasma lycopene concentrations of ∼ 1 $\mu$M which is at the lower limit of its activity in cell culture. Rats and mice are poor accumulators of lycopene and other carotenoids making them poor models for the study of cancer prevention and control. Of the 19 animal studies for various cancer sites, lycopene showed a positive effect in 10 studies but negative in 2 prostate cancer studies. In vivo prevention of leukocyte DNA damage in humans has been mostly studied using tomato product supplementation but lycopene supplementation appeared to reduce oxidative DNA damage as well as tomato product supplementation. Lycopene appears to be bioactive in intefering with carcinogenesis but the actions of phytoene, phytofluene or cyclolycopene cannot be ruled out since these compounds were present in most of the lycopene material used for these studies. Although lycopene remains as a promising agent, especially for cancer control, exploring interactions with other tomato phytochemicals and with current prostate cancer therapies should be encouraged.