• 제목/요약/키워드: Magnetic interactions

검색결과 215건 처리시간 0.026초

Syndecan-4 cytoplasmic domain could disturb the multilamellar vesicle

  • Kim, Suhk-Mann
    • 한국자기공명학회논문지
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    • 제13권1호
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    • pp.1-6
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    • 2009
  • Syndecan-4 cytoplasmic domain was tested to confirm the interactions with the bilayer membrane using $^{31}P$ solid-state NMR measurements. Syndecan-4 was known as a coreceptor with integrins in the cell adhesion. The syndecan-4 V region is not understood of its functional roles and tested its ability of the interaction with multilamellar vesicles. The $^{31}P$ powder pattern was dramatically changed and showed isotropic peak which imply the bilayer membrane changed its topology to the micelle-like structure. Especially, phosphatidylcholine membrane was affected this effect more than phosphatidylethanolamine membrane.

RNA-Protein Interactions and Protein-Protein Interactions during Regulation of Eukaryotic Gene Expression

  • Varani, Luca;Ramos, Andres;Cole, Pual T.;Neuhaus, David;Varani, Gabriele
    • 한국자기공명학회논문지
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    • 제2권2호
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    • pp.152-157
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    • 1998
  • The diversity of RNA functions ranges from storage and propagation of genetic information to enzymatic activity during RNA processing and protein synthesis. This diversity of functions requires an equally diverse arrays of structures, and, very often, the formation of functional RNA-protein complexes. Recognition of specific RNA signals by RNA-binding proteins is central to all aspects of post-transcriptional regulation of gene expression. We will describe how NMR is being used to understand at the atomic level how these important biological processes occur.

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Solution NMR spectroscopy for investigation of liquid-liquid phase separation

  • Saio, Tomohide;Okumura, Masaki;Lee, Young-Ho
    • 한국자기공명학회논문지
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    • 제24권2호
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    • pp.47-52
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    • 2020
  • Liquid-liquid phase separation (LLPS) of biomolecules, a newly-found phase behavior of molecules in the liquid phase, has shown to its relationship to various biological function and misfolding diseases. Extensive studies have increasingly revealed a general mechanism of LLPS and characterized the liquid droplet; ho wever, intermolecular interactions of proteins and structural states of LLPS-inducing proteins inside of the droplet remain largely unknown. Solution NMR spectroscopy has emerged as a powerful approach as it provides invaluable information on protein intermolecular interactions and structures at the atomic and residue level. We herein comprehensively address useful techniques of solution NMR including the effect of paramagnetic relaxation enhancement for the study on the LLPS and droplet based on recent studies.

NMR Study on Binding Interactions of Cationic Porphyrin Derivatives with double helical $d(CGCGAATTCGCG)_2$

  • Huh, Sungho;Hong, Seokjoo
    • 한국자기공명학회논문지
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    • 제5권2호
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    • pp.118-129
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    • 2001
  • Binding interactions of cationic porphyrins, T4MPyP and TMAP with DNA oligomer d(CGCGAATTCGCG), were studied with NMR spectroscopy, W and CD spectroscopic method. Two porphyrins showed significant differences in NMR, UV and CD data upon binding to DNA. T4MPyP was considered to position more closely to DNA bases through partial intercalation as well as ionic intercalation between the positive charges of porphyrin and phosphate group of DNA at 5’-GC-3’steps. Contrast to this, TMAP was thought to bind to phosphate of DNA more or less outside of the groove.

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Magnetic properties and magnetocaloric effect of Sr-doped Pr0.7Ca0.3MnO3 compounds

  • Yen, Pham Duc Huyen;Dung, Nguyen Thi;Thanh, Tran Dang;Yu, Seong-Cho
    • Current Applied Physics
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    • 제18권11호
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    • pp.1280-1288
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    • 2018
  • In this work, we pointed out that Sr substitution for Ca leads to modify the magnetic and magnetocaloric properties of $Pr_{0.7}Ca_{0.3-x}Sr_xMnO_3$ compounds. Analyzing temperature dependence of magnetization, M(T), proves that the Curie temperature ($T_C$) increased with increasing Sr content (x); $T_C$ value is found to be 130-260 K for x = 0.0-0.3, respectively. Using the phenomenological model and M(T,H) data measured at several applied magnetic field, the magnetocaloric effect of $Pr_{0.7}Ca_{0.3-x}Sr_xMnO_3$ compounds has been investigated through their temperature and magnetic field dependences of magnetic entropy change ${\Delta}S_m$(T,H) and the change of the specific heat change ${\Delta}C_P$(T,H). Under an applied magnetic field change of 10 kOe, the maximum value of $-{\Delta}S_m$ is found to be about $3J/kg{\cdot}K$, and the maximum and minimum values of ${\Delta}C_P$(T) calculated to be about ${\pm}60J/kg{\cdot}K$ for x = 0.3 sample. Additionally, the critical behaviors of $Pr_{0.7}Ca_{0.3-x}Sr_xMnO_3$ compounds around their $T_C$ have been also analyzed. Results suggested a coexistence of the ferromagnetic short- and long-range interactions in samples. Moreover, Sr-doping favors establishing the short-range interactions.

전이금속산화물 클러스터의 자기구조 및 자기이방성에너지 계산 (The Magnetic Structure and Magnetic Anisotropy Energy Calculations for Transition Metal Mono-oxide Clusters)

  • 박기택
    • 한국자기학회지
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    • 제21권1호
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    • pp.1-4
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    • 2011
  • 정육면체 전이금속 산화물 FeO, MnO의 자기적 상호작용을 제1원리의 범밀도함수법을 이용하여 계산하였다. 그 결과, 모두 초교환작용으로 인해 반강자성적 상호작용이 가장 낮은 에너지를 가지고 있었다. 자기이방성은 반강자성 스핀 배열의 FeO 클러스터에서만 발견되었다. 그 원인은 <111> 방향으로 각운동량을 가지는 3d down-spin 전자의 스핀-궤도 결합에 기인하였다.

Influence of Working Pressure on The Magnetic Properties of Tb(Fe0.55Co0.45)1.5 Thin Films

  • Tu, Le Tuan;Duc, Nguyen Huu;Jeong, Jong-Ryul;Kim, Cheol-Gi
    • Journal of Magnetics
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    • 제13권4호
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    • pp.160-162
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    • 2008
  • In this work the magnetic anisotropies of magnetostriction material $Tb(Fe_{0.55}Co_{0.45})_{1.5}$ (named a-TerfecoHan) films were investigated with respect to working pressures in the range 1-7 mTorr. The results obtained show that perpendicular magnetic anisotropy (PMA) can be obtained at a working pressure above 5.1 mTorr. XRD was utilized to clarify the origin of the PMA observed in $Tb(Fe_{0.55}Co_{0.45})_{1.5}$ films, and revealed that all samples were amorphous. Therefore, we propose that the PMA effect is explained by stress produced in film due to internal relaxation process and magnetic anisotropy enhancements caused by magnetoelastic interactions.

자가공명영상(Magnetic Resonance Imaging)의 기본원리 (Basic Principles of Magnetic Resonance Imaging)

  • 조봉혜
    • 치과방사선
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    • 제29권1호
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    • pp.7-20
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    • 1999
  • Magnetic resonance imaging with its superior soft tissue contrast resolution and absence of beam hardening artifacts, combined with its ability to perform multiplanar imaging, is now effective tool in diagnostic imagings. Magnetic resonance is primarily a phenomenon that involves atomic nuclei. It provides totally new clinical informations with no known hazards through the use of very weak interactions with endogenous stable magnetic atomic nuclei. This article briefly summarizes the basic mechanism of generation and detection of the signals and general sorts of tissue properties which can influence the signals and thereby give rise to tissue contrast. It also describes how the machine-operating parameters can be used to manipulate the tissue contrast observed in the image.

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EFFECT OF MAGNETIC FIELD ON LONGITUDINAL FLUID VELOCITY OF INCOMPRESSIBLE DUSTY FLUID

  • N. JAGANNADHAM;B.K. RATH;D.K. DASH
    • Journal of applied mathematics & informatics
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    • 제41권2호
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    • pp.401-411
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    • 2023
  • The effects of longitudinal velocity dusty fluid flow in a weak magnetic field are investigated in this paper. An external uniform magnetic field parallel to the flow of dusty fluid influences the flow of dusty fluid. Besides that, the problem under investigation is completely defined in terms of identifying parameters such as longitudinal velocity (u), Hartmann number (M), dust particle interactions β, stock resistance γ, Reynolds number (Re) and magnetic Reynolds number (Rm). While using suitable transformations of resemblance, The governing partial differential equations are transformed into a system of ordinary differential equations. The Hankel Transformation is used to solve these equations numerically. The effects of representing parameters on the fluid phase and particle phase velocity flow are investigated in this analysis. The magnitude of the fluid particle is reduced significantly. The result indicates the magnitude of the particle reduced significantly. Although some of our numerical solutions agree with some of the available results in the literature review, other results differs because of the effect of the introduced magnetic field.