• 제목/요약/키워드: structure-activity

검색결과 3,401건 처리시간 0.032초

The effect of field-line twist on the dynamic and electric current structures of emerging magnetic field on the Sun

  • An, Jun-Mo;Lee, Hwan-Hee;Kang, Ji-Hye;Magara, Tetsuya
    • 천문학회보
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    • 제36권2호
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    • pp.102.1-102.1
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    • 2011
  • In this study we use three-dimensional magnetohydrodynamic simulations to investigate how the dynamic state of emerging magnetic field is related to the twist of field lines. Emerging magnetic field forms a magnetic structure on the Sun where various kinds of activity such as solar flares, jets, and coronal mass ejections are observed. To understand the physical mechanism for producing such activity, we have to know the dynamic nature of this structure. Since flares are the manifestation of rapidly dissipating electric current in the corona, we also investigate the distribution of current density inside the structure and examine how it depends on the field-line twist. To demonstrate the dynamic structure of emerging magnetic field, we focus on the factors characterizing the geometric property and stratification of emerging magnetic field, such as the curvature of field line and the scale height of field strength. These two factors show that emerging field forms a two-part structure in which the central part is close to a force-free state while the outer marginal part is in a fairly dynamic state where magnetic pressure force is dominant. We discuss how the field-line twist affects the two-part structure and also explain a possible relation between electric current structure and sigmoid observed in a preflare phase.

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낙동강 유역의 지속적인 이용을 위한 미래예측 (Simulating the Future of Nakdong River Basin for the Sustainable Use)

  • 김진이;이석모
    • 한국환경과학회지
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    • 제10권4호
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    • pp.253-258
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    • 2001
  • A macroeconomic minimodel was simulatedto suggest the public for sustainable us of Nakdong River Basin. The minimodel for the simulation shows the interrelationships between natural environment and economic activity. Topsoil, water, economic assets, and money stock are plotted for 300 years, beginning with 1996 in each simulation. The computer simulation runs suggest that the Nakdong River Basin system in the near future may strongly be influenced by the favorable availability of outside resources, while the economic assets and money stock may be declined by indigenous environmental stock depletion. The simulation run made under the constant decrease in systems purchased inputs with investment ratio of developed country and for sustainable use. The results of simulation shows the recover of natural environment and decrease of economic activity under these condition. Therefore, the economic structure of Nakdong River Basin should be transformed from the present industrial structure to the social-economic structure based on an ecological-recycling concept which depend on renewable resources rather than industrial structural which depend on outside resources.

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Structure-function analysis of PRDI DNA polymerase

  • Jung, Guhung
    • 미생물과산업
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    • 제16권3호
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    • pp.6-14
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    • 1990
  • PRDI DNA polymerase is the smallest member of the family B DNA polymerase (Jung et al., 1987). This DNA polyerase is specified by bacteriophage PRDI which infects a wide variety of gram-negative bacteria(Mindich and Bamford, 1988). Because PRDI is highly amenable to genetic and biochemical manipulation, it is a convenient model system with which to study structure-function relationships of DNA polymerase molecules. To determine the functional roles of the highly conserved regions of the family B DNA polymerases, we have initiated site-directed mutagenesis with PRD1 DNA polymerase, and our results show that mutations at the conserved regions within PRD1 DNA polymerase inactivate polymerase complementing activity and catalytic activity.

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Proline Effect on Structure and Activity of Antimicrobial Peptides

  • Suh, Jeong-Yong;Park, Byong-Seok
    • 한국생물물리학회:학술대회논문집
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    • 한국생물물리학회 1998년도 학술발표회
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    • pp.19-19
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    • 1998
  • Structure and activity of a helical antimicrobial peptide with a central proline (P14) and its alanine derivative (P14A) were investigated by NMR spectroscopy and biological assay. Chemical shift analysis showed that both of the peptides formed curved helix and P14 showed diminished stability near proline due to hindrance of hydrogen bonding by proline.(omitted)

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Preparation of High Transparent Olefin Copolymer with Metallocene Catalyst

  • Lee, Dong-Ho;Choi, Yeon-Seok;Ha, Ki-Ryong
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.1028-1029
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    • 2003
  • The copolymerization of ethylene and norbornene was carried out with ansa-metallocene and modified methylaluminoxane (MMAO) cocatalyst. The copolymerization behavior was changed with the structure of metallocene catalysts. In addition the catalyst activity was dependent on the structure of MMAO, i.e.. MMAO-4 which contains less i-butyl group compared to MMAO-3A exhibited higher catalyst activity than MMAO-3A. The glass transition temperature and the composition of the produced copolymer were not affected by MMAO type.

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Quantitative Structure-Activity Relationship(QSAR) Study of New Fluorovinyloxycetamides

  • 조두호;이성광;김범태;노경태
    • Bulletin of the Korean Chemical Society
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    • 제22권4호
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    • pp.388-394
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    • 2001
  • Quantitative Structure-Activity Relationship (QSAR) have been established of 57 fluorovinyloxyacetamides compounds to correlate and predict EC50 values. Genetic algorithm (GA) and multiple linear regression analysis were used to select the descriptors and to generate the equations that relate the structural features to the biological activities. This equation consists of three descriptors calculated from the molecular structures with molecular mechanics and quantum-chemical methods. The results of MLR and GA show that dipole moment of z-axis, radius of gyration and logP play an important role in growth inhibition of barnyard grass.

Molecular modeling study of indeno[1,2-c]isoquinolines and 3-arylisoquinolines using CoMFA

  • Kang, Sung-Kyung;Manhk, Le-Quynh;Cho, Won-Jea
    • 대한약학회:학술대회논문집
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    • 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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    • pp.171.1-171.1
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    • 2003
  • ·The potent antitumor activities of 3-arylisoquinolines promoted us to explore the structure-activity relationship of these compounds. A series of 3-arylisoquinoline derivatives were evaluated for antitumor cytotoxicity against human lung tumor cell (A 549). For the next stage, we decided to prepare the constrained form of 3-arylisoquinolines as indeno[1,2-c]isoquinolines. As a result, diverse spectrum against human tumor cell lines was obtained. In order to study structure-activity relationship (SAT) of these compounds the comparative molecular field analysis (CoMFA) was carried out. (omitted)

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배추좀나방에 대한 flupyrazofos KH502의 살충활성 CoMFA (Insecticidal activity of flupyrazofos KH502 against Plutella xylostella: a CoMFA study)

  • 김수경;이관구;김혜원;유성은;황기준;공영대
    • 농약과학회지
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    • 제8권3호
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    • pp.162-167
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    • 2004
  • 십자화과 식물을 가해하는 세계적으로 중요한 해충의 하나인 배추좀나방(diamondback moth, Plutella xylostella)을 방제를 하기위하여 개발된 새로운 형태의 thiophosphoryl pyrazole계 살충제 KH502 유도체들의 구조와 살충활성을 CoMFA 방법으로 조사한 결과 효소의 결합부위에서 가장 중요한 역할을 하는 작용기는 trifluoro-methyl group과 thiophosphoryl group으로 밝혀졌다. 이와 같은 3D-QSAR 분석결과는 새로운 배추좀나방 방제용 살충제를 설계하는데 유용한 정보로 이용할 수 있을 것이다.