• 제목/요약/키워드: Magnetic resonance

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NMR 양자 컴퓨터

  • 이순칠
    • 한국자기공명학회:학술대회논문집
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    • 한국자기공명학회 2000년도 동계총회 및 제16회 자기공명 학술발표회
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    • pp.5-6
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    • 2000
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Molecular Dynamics of the C-Terminal Domain Mouse CDT1 Protein

  • Khayrutdinov, Bulat I.;Bae, Won-Jin;Kim, Jeong-Ju;Hwang, Eun-Ha;Yun, Young-Mi;Ryu, Kyoung-Seok;Cheong, Hae-Kap;Kim, Yu-Gene;Cho, Yun-Je;Jeon, Young-Ho;Cheong, Chae-Joon
    • 한국자기공명학회논문지
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    • 제11권1호
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    • pp.30-41
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    • 2007
  • The backbone molecular dynamics of the C-terminal part of the mouse Cdt1 protein (tCdt1, residues 420-557) was studied by high field NMR spectroscopy. The Secondary structure of this protein was suggested by analyzing of chemical shift of backbone atoms with programs TALOS and PECAN, together with NOE connectivities from 3D $^{15}N-HSQC-NOESY$ data. Measurement of dynamic parameters $T_1,\;T_2$ and NOE and limited proteolysis experiment provided information for domain organization of tCdt1(420-557). Analysis of the experimental data showed that the C-terminal part of the tCdt1 has well folded domain for residues 455-553. The residues 420-453 including ${\alpha}-helix$ (432-441) are flexible and probably belong to other functional domain in intact full length Cdt1 protein.

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Unwanted effects due to interactions between dental materials and magnetic resonance imaging: a review of the literature

  • Chockattu, Sherin Jose;Suryakant, Deepak Byathnal;Thakur, Sophia
    • Restorative Dentistry and Endodontics
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    • 제43권4호
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    • pp.39.1-39.20
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    • 2018
  • Magnetic resonance imaging (MRI) is an advanced diagnostic tool used in both medicine and dentistry. Since it functions based on a strong uniform static magnetic field and radiofrequency pulses, it is advantageous over imaging techniques that rely on ionizing radiation. Unfortunately, the magnetic field and radiofrequency pulses generated within the magnetic resonance imager interact unfavorably with dental materials that have magnetic properties. This leads to unwanted effects such as artifact formation, heat generation, and mechanical displacement. These are a potential source of damage to the oral tissue surrounding the affected dental materials. This review aims to compile, based on the current available evidence, recommendations for dentists and radiologists regarding the safety and appropriate management of dental materials during MRI in patients with orthodontic appliances, maxillofacial prostheses, dental implants, direct and indirect restorative materials, and endodontic materials.

Electron Paramagnetic Resonance Study of Al-incorporated ZnO:Mn Diluted Magnetic Semiconductors

  • Park, Jun Kue;Lee, K.W.;Choi, D.M.;Lee, Cheol Eui
    • Journal of the Korean Physical Society
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    • 제73권12호
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    • pp.1884-1888
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    • 2018
  • We have employed electron paramagnetic resonance spectroscopy and magnetization measurements in order to study the effect of Al-incorporation on the magnetic interactions in ZnO:Mn diluted magnetic semiconductors. Al-doping is shown to decrease the antiferromagnetic correlation and to increase the ferromagnetic interaction, which is attributed to the hydrogen-mediated ferromagnetic Mn complexes in our Mn-doped ZnO samples.

Characterization of Drawn Polyethylene by Solid State $^{13}C$ Magic Angle Spinning NMR

  • Han, Oc-Hee
    • 한국자기공명학회논문지
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    • 제2권1호
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    • pp.24-32
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    • 1998
  • Drawn polyethylene was studied by 13C cross polarization magic angle spinning techniques. Solid-solid phase transition from orthorhombic to monoclinic crystalline phase by drawing was observed. In addition, using a synchronized magic angle spinning 2 dimension technique, we confirmed that macroscopic ordering of the polyethylene was produced by drawing.

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A Review on the RF Coil Designs and Trends for Ultra High Field Magnetic Resonance Imaging

  • Hernandez, Daniel;Kim, Kyoung-Nam
    • Investigative Magnetic Resonance Imaging
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    • 제24권3호
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    • pp.95-122
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    • 2020
  • In this article, we evaluated the performance of radiofrequency (RF) coils in terms of the signal-to-noise ratio (S/N) and homogeneity of magnetic resonance images when used for ultrahigh-frequency (UHF) 7T magnetic resonance imaging (MRI). High-quality MRI can be obtained when these two basic requirements are met. However, because of the dielectric effect, 7T magnetic resonance imaging still produces essentially a non-uniform magnetic flux (|B1|) density distribution. In general, heterogeneous and homogeneous RF coils may be designed using electromagnetic (EM) modeling. Heterogeneous coils, which are surface coils, are used in consideration of scalability in the |B1| region with a high S/N as multichannel loop coils rather than selecting a single loop. Loop coils are considered state of the art for their simplicity yet effective |B1|-field distribution and intensity. In addition, combining multiple loop coils allows phase arrays (PA). PA coils have gained great interest for use in receiving signals because of parallel imaging (PI) techniques, such as sensitivity encoding (SENSE) and generalized autocalibrating partial parallel acquisition (GRAPPA), which drastically reduce the acquisition time. With the introduction of a parallel transmit coil (pTx) system, a form of transceiver loop arrays has also been proposed. In this article, we discussed the applications and proposed designs of loop coils. RF homogeneous coils for volume imaging include Alderman-Grant resonators, birdcage coils, saddle coils, traveling wave coils, transmission line arrays, composite right-/left-handed arrays, and fusion coils. In this article, we also discussed the basic operation, design, and applications of these coils.

Magnetic Resonance Imaging of Idiopathic Herniation of the Lingual Gyrus: a Case Report

  • Seok, Hee Young;Lee, Dong Hoon
    • Investigative Magnetic Resonance Imaging
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    • 제21권3호
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    • pp.195-198
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    • 2017
  • Idiopathic brain herniation is a rare condition. We believe that this is the first reported case of idiopathic herniation of the lingual gyrus. The case involves a 57-year-old woman presenting with frontal headache without overt visual symptoms. Magnetic resonance imaging (MRI) revealed an idiopathic herniation of the lingual gyrus of the occipital lobe extending into the quadrigeminal cistern. No other adjacent intracranial abnormalities were observed. Although some conditions may be considered in the differential diagnosis, accurate diagnosis of idiopathic brain herniation in medical practice can prevent unnecessary additional imaging procedures and invasive open biopsy in patients with typical imaging findings.