• Title/Summary/Keyword: Disruption

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Tidal Disruption Flares from Stars on Bound Orbits

  • Hayasaki, Kimitake;Stone, Nicholas;Loeb, Abraham
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.2
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    • pp.60.1-60.1
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    • 2013
  • We study tidal disruption and subsequent mass fallback process for stars approaching supermassive black holes on bound orbits, by performing three dimensional Smoothed Particle Hydrodynamics simulations with a pseudo-Newtonian potential. We find that the mass fallback rate decays with the expected -5/3 power of time for parabolic orbits, albeit with a slight deviation due to the self-gravity of the stellar debris. For eccentric orbits, however, there is a critical value of the orbital eccentricity, significantly below which all of the stellar debris is bound to the supermassive black hole. All the mass therefore falls back to the supermassive black hole in a much shorter time than in the standard, parabolic case. The resultant mass fallback rate considerably exceeds the Eddington accretion rate and substantially differs from the -5/3 power of time. We also show that general relativistic precession is crucial for accretion disk formation via circularization of stellar debris from stars on moderately eccentric orbits.

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Studies on the Endocrine Disruption in Wildlife Fish (어류생체지표를 이용한 내분비계장애 연구)

  • 구자민;류지성;정규혁;이철우;박응로;박광식
    • Environmental Analysis Health and Toxicology
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    • v.16 no.4
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    • pp.197-204
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    • 2001
  • Endocrine disruption in crucian carp (Carassius auratus) living in the branch of Han River were examined. Vitellogenin level in plasma was measured using ELISA system and aromatase mRNA level in brain was observed using RT-PCR technique. In all female fish, vitellogenin levels were in the range of 20∼40 $\mu\textrm{g}$/ml and aromatase mRNA expression could be detected on the agarose gel after RT-PCR. However, in case of males, vitellogenin level was elevated in only one fish, while vitellogenin was hardly detected in others. Aromatase was expressed in all males although the levels were relatively lower than the level in female fish. Testis-ova and any other histological changes of reproductive organ were not shown in both sexes.

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Disruption time scale of merged halos in a dense cluster environment

  • Shin, Jihye;Taylor, James E.;Peng, Eric
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.2
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    • pp.60.1-60.1
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    • 2016
  • To obtain a reliable estimate of the cold dark matter (CDM) substructure mass function in a dense cluster environment, one needs to understand how long a merged halo can survive within the host halo. Measuring disruption time scale of merged halos in a dense cluster environment, we attempt to construct the realistic CDM mass function that can be compared with stellar mass functions to get a stellar-to-halo mass ratio. For this, we performed a set of high-resolution simulations of cold dark matter halos with properties similar to the Virgo cluster. Field halos outside the main halo are detected using a Friend-of-Friend algorithm with a linking length of 0.02. To trace the sub-halo structures even after the merging with the main halo, we use their core structures that are defined to be the most 10% bound particles.

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In Situ Sapheneous Vein Arterial Bypass; A Case Report (자연위치의 복재정맥을 이용한 하지동맥 우회술;치험 1례)

  • 문남출
    • Journal of Chest Surgery
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    • v.26 no.11
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    • pp.881-885
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    • 1993
  • In the last few years there has been a resurgenceof interest in in-situ saphenous vein arterial bypass for lower extremity revascularization because of improved patency rates. we performed 1 in situ bypass oreration using the intraluminal valve-disruption tecnique. A 65-year-old female who had ztherosclerotic obstruction in the superficial and popliteal arteries underwent in situ saphenous vein arterial bypass. After harvesting of saphenous vein, we used LeMaitre retrograde valvulotome for valve-disruption technique. Completion of the arterrigraphy was performed to evaluate bothh the anastomoses. The two side brances were all ligated. In situ saphenous vein arterial bypass has become the procedure of choice for distal reconstruction in severely ischemic lower extremities because of improved long-term patency compared with reversed-saphenous vein bypass procedure.

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Candidacidal Effects of Rev (11-20) Derived from HIV-1 Rev Protein

  • Lee, Juneyoung;Lee, Dong Hwan;Lee, Dong Gun
    • Molecules and Cells
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    • v.28 no.4
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    • pp.403-406
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    • 2009
  • Rev is an essential regulatory protein for HIV-1 replication. Rev (11-20) is known as the significant region regarding the function of a nuclear entry inhibitory signal (NIS) of Rev. In this study, anticandidal effects and mechanism of action of Rev (11-20) were investigated. The result exhibited that Rev (11-20) contained candidacidal activities. To understand target site(s) of Rev (11-20), the intracellular localization of the peptide was investigated. The result showed that Rev (11-20) rapidly accumulated in the fungal cell surface. The cell wall regeneration test also indicated that Rev (11-20) exerted its anticandidal activity to fungal plasma membrane rather than cell wall. The fluorescent study using 1,6-diphenyl-1,3,5-hexatriene (DPH) further confirmed the membrane-disruption mechanism(s) of Rev (11-20). The present study suggests that Rev (11-20) possesses significant potential regarding therapeutic agents for treating fungal diseases caused by Candida species in humans.