• 제목/요약/키워드: $T_2$ relaxation time

검색결과 136건 처리시간 0.029초

자기공명영상장치(磁氣共鳴映像裝置)에서 움직임허상(虛像)의 위치제어(位置制御)에 관(關)한 연구(硏究) (A Study on Locational Control of Motion Ghost in Magnetic Imaging System)

  • 이후민
    • 대한방사선기술학회지:방사선기술과학
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    • 제16권2호
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    • pp.19-26
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    • 1993
  • Magnetic Resonance Image represents three-dimensional diagnostic imaging technique using both nuclear magnetic resonance phenomenon and computer. Compared with computed tomography (CT), MRI have advantages harmless to patient's body, three-dimensional image with high resolution and disadvantages long data acquisition time because of long T1 relaxation time, relatively low signal to noise ratio, high cost of setting, also. As physiologic motion of tissue results in motion ghost in MRI, high 2.0Tesla make improve low signal to noise ratio. This study have aim to improve image quality with controling motion ghost of tissue. Supposing a moving pixel in constant frequency, one pixel make two ghosts which are same size and different anti-phase. So, this study will show adjust parameter on locational control of motion ghost. Author made moving phantom replaced by respiratory movement of human, researched change of motion frequency, FOV by location shift, and them decided optimal FOV (field of view). The results are as follows: 1. The frequency content of the motion determines how far the image always appear in phase-encoding direction, the morphology of the ghost image is characteristic of the direction of the motion and its amplitude. 2. Double FOV of fixed signal object for locational control of motion ghost is recommended. Decreasement of spatial resolution by increasing FOV can compensate on increasing of matrix in spite of scan time increasement.

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[ $^1H$ ] Nuclear Magnetic Resonance Study of Ferroelectric $(NH_4)_3H(SO_4)_2$

  • Choi, S.H.;Han, K.S.;Kwon, S.K.;Nam, S.K.;Choi, H.H.;Lee, Moo-Hee;Lim, Ae-Ran
    • 한국자기공명학회논문지
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    • 제11권2호
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    • pp.64-72
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    • 2007
  • [ $^1H$ ] nuclear magnetic resonance (NMR) experiments have been performed at 30 - 300 K and 7 T to investigate dynamics of hydrogen bond network in the single crystal $(NH_4)_3H(SO_4)_2$. The two proton sites, ammonium proton and hydrogen-bond proton, are identified from the $^1H$ NMR MAS spectrum at 340 K. As temperature decreases, the $^1H$ NMR spectrum shifts to the higher frequency side with a larger linewidth. The spectrum at 65 K shows a distinctive change in line shape toward the ferroelectric transition at 63 K. The measured values of $T_1$ for ammonium and hydrogen-bond protons are similar in the whole range of temperature. $T_1$ of $^1H$ NMR shows a gradual decrease down to 120 K and starts to steeply increase below 100 K. Then $T_1$ shows abrupt decrease below 70 K with a sharp minimum at 63 K, where the ferroelectric transition occurs. This temperature dependence of spectrum and $T_1$ clearly prove that the large change in the dynamics of hydrogen bond network is associated with the ferroelectric phase transition at 63 K.

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Nanoscale imaging of rat atrial myocytes by scanning ion conductance microscopy reveals heterogeneity of T-tubule openings and ultrastructure of the cell membrane

  • Park, Sun Hwa;Kim, Ami;An, Jieun;Cho, Hyun Sung;Kang, Tong Mook
    • The Korean Journal of Physiology and Pharmacology
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    • 제24권6호
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    • pp.529-543
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    • 2020
  • In contrast to ventricular myocytes, the structural and functional importance of atrial transverse tubules (T-tubules) is not fully understood. Therefore, we investigated the ultrastructure of T-tubules of living rat atrial myocytes in comparison with ventricular myocytes. Nanoscale cell surface imaging by scanning ion conductance microscopy (SICM) was accompanied by confocal imaging of intracellular T-tubule network, and the effect of removal of T-tubules on atrial excitation-contraction coupling (EC-coupling) was observed. By SICM imaging, we classified atrial cell surface into 4 subtypes. About 38% of atrial myocytes had smooth cell surface with no clear T-tubule openings and intracellular T-tubules (smooth-type). In 33% of cells, we found a novel membrane nanostructure running in the direction of cell length and named it 'longitudinal fissures' (LFs-type). Interestingly, T-tubule openings were often found inside the LFs. About 17% of atrial cells resembled ventricular myocytes, but they had smaller T-tubule openings and a lower Z-groove ratio than the ventricle (ventricular-type). The remaining 12% of cells showed a mixed structure of each subtype (mixed-type). The LFs-, ventricular-, and mixed-type had an appreciable amount of reticular form of intracellular T-tubules. Formamide-induced detubulation effectively removed atrial T-tubules, which was confirmed by both confocal images and decreased cell capacitance. However, the LFs remained intact after detubulation. Detubulation reduced action potential duration and L-type Ca2+ channel (LTCC) density, and prolonged relaxation time of the myocytes. Taken together, we observed heterogeneity of rat atrial T-tubules and membranous ultrastructure, and the alteration of atrial EC-coupling by disruption of T-tubules.

Comparisons for the Abnormality of Breathing Pattern, Kinesiophobia and Flexion Relaxation Phenomenon in Patients with Chronic Low Back Pain and Healthy Person during Flexion and Extension of the Trunk

  • Yoon, Junggyu
    • 국제물리치료학회지
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    • 제10권2호
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    • pp.1750-1755
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    • 2019
  • Background: Most of the previous researches on the abnormality of breathing pattern have focused on the silence of functional movements owing to such abnormality, however, have not been clearly identified the relationship between the abnormal breathing pattern on one hand and kinesiophobia and flexion relaxation phenomenon (FRP) on the other hand. Objective: To compare patients with chronic low back pain (CLBP) and healthy person in the abnormality of breathing pattern, kinesiophobia, and FRP during flexion and extension of the trunk. Design: Case-control study. Methods: The research subjects consisted of a group of 15 healthy adults and another group of 15 patients with CLBP. Capnography was used to measure the endtidal $CO_2$ ($EtCO_2$) and respiratory quotient (RQ). The muscle activity of multifidus and erector spinae of the subjects was measured during flexion and extension of the trunk to identify their FRP. The Nijmegen Questionnaire (NQ) and Tampa Scale of Kinesiophobia (TSK) were utilized to measure their breathing patterns and kinesiophobia, respectively. The Kolmogorov-Smirnov (K-S) test was conducted in order to analyze the normal distribution of the measured data. Their general characteristics were identified by the descriptive statistics and the independent t-test was performed to identify the differences between the two groups in terms of abnormality of breathing pattern, kinesiophobia, and FRP. The level of significance was set at ${\alpha}=.05$. Results: The patients with CLBP had significantly less $EtCO_2$ and shorter breathing hold time (BHT) than normal healthy person (p<.05). The patient with CLBP also had significantly greater kinesiophobia than healthy person (p<.05), and had less FRP than the healthy person (p<.01). Conclusions: These results suggest that the CLBP had greater abnormality of breathing pattern and kinesiophobia with less FRP than healthy person.

Magnetic Resonance Imaging as a Biomarker for Duchenne Muscular Dystrophy

  • Lim, Woo-taek
    • 한국전문물리치료학회지
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    • 제22권3호
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    • pp.98-105
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    • 2015
  • Muscular dystrophy is a hereditary musculoskeletal disorder caused by a mutation in the dystrophin gene. Duchenne muscular dystrophy (DMD) is one of the most common, and progresses relatively faster than other muscular dystrophies. It is characterized by progressive myofiber degeneration, muscle weakness and ultimately ambulatory loss. Since it is an X-linked recessive inheritance, DMD is mostly expressed in males and rarely expressed or less severe in females. The most effective measurement tool for DMD is magnetic resonance imaging (MRI), which allows non-invasive examination of longitudinal measurement. It can detect progressive decline of skeletal muscle size by measuring a maximal cross-sectional area of skeletal muscle. Additionally, other techniques in MRI, like $T_2$-weighted imaging, assess muscle damage, including inflammation, by detecting changes in $T_2$ relaxation time. Current MRI techniques even allow quantification of metabolic differences between affected and non-affected muscles in DMD. There is no current cure, but physical therapist can improve their quality of life by maintaining muscle strength and function, especially if treatment (and other forms of medical intervention) begins in the early stages of the disease.

STORAGE OF BROCCOLI BY MAKING THE WATER STRUCTURED -Suppression of metabolism-

  • Oshita, S.;Seo, Y.;Kawagoe, Y.;Rahman, M.A.
    • 한국농업기계학회:학술대회논문집
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    • 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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    • pp.918-925
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    • 1996
  • The effect of structured water by dissolution of xenon was examined from the view point of the suppression of both browning and respiratory metabolism of broccoli. The structured water is formed duet to hydrophobic interaction when xenon gas dissolves into water. NMR measurements were carried out to determine proton spin-spin relaxation time, T2, for water. There was a difference in proton T2 between distilled water and structured water. This can be interpreted as the change of water structure. Fro the broccoli cut in half stored for 16 days at 279K, the section color did not change appreciably for the sample whose water was structured by dissolution of xenon whose initial partial pressure was 0.39MPa. In contrast to this, the browning of section surface was observed for the sample stored under the condition of nitrogen gas at the same partial pressure as xenon and for the sample stored under atmospheric condition . These results led to the conclusion that the suppression of b owning by oxidation was due to structured water but not to applied pressure. Adding to this, the water structured by xenon has resulted in suppression of respiratory metabolism of broccoli.

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고온인가에 따른 에폭시 복합체의 열화 및 유전특성평가 (Estimation of Degradation and Dielectric Properties for Epoxy Composites doe to Applying High Temperature)

  • 왕종배;이준웅;김재환
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1995년도 추계학술대회 논문집
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    • pp.175-178
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    • 1995
  • Distribution of relaxation time is presented in the Cole-Cole arc diagram with frequency parameter. In the case of estimation of activation energy for main chains, maximum loss frequencies of ${\alpha}$ peaks, f$\sub$m/(${\alpha}$) display curved change according to the WLF type with variations of temperature. Structural change by the filling of filler and degradation by the thermal aging can be estimated from the WLF factors, C$_1$and C$_2$in Log f$\sub$m/-1/T curves which reflect the variations of free volume and thermal expansivity of composites.

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Non-Newtonian Intrinsic Viscosities of Biopolymeric and Nonbiopolymeric Solutions (I)

  • Jang, Chun-Hag;Kim, Jong-Ryul;Ree, Tai-Kyue
    • Bulletin of the Korean Chemical Society
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    • 제8권4호
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    • pp.318-324
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    • 1987
  • Experimental results for viscous flow of poly (${\gamma}$ -methyl L-glutamate) solutions have been published elsewhere. The data of $[{\eta}]^f / [{\eta}]^0$ are expressed by the following equation, $\frac{[{\eta}^f]}{[{\eta}^{\circ}]}=1-\frac{A}{\eta^\circ}{1-\frac{sin^{-1}[{\beta}_2(f/{\eta}_0)\;{e}xp\;(-c_2f^2/{\eta}_0^2kT)]}{{\beta}_2f/{\eta}_0}$ (A1) where $[{\eta}]^f\; and\; [{\eta} ]^0$ are the intrinsic viscosity at shear stress f and zero, respectively, $ A{\equiv}lim\limits_{C{\rightarrow}0}[(1/C)(X_2/{\alpha}_2)({\beta}_2/{\eta}_0)],{\eta}_0$ viscosity of the solvent, ${\beta}_2$ is the relaxation time of flow unit 2, $c_2$ is a constant related to the elasticity of flow unit 2. The theoretical derivation of Eq.(A1) is given in the text. The experimental curves of $[{\eta}]^f / [{\eta}]^0$ vs. log f are compared with the theoretical curves calculated from Eq.(A1) with good results. Eq.(A1) is also applied to non-biopolymeric solutions, and it was found that in the latter case $c_2 = 0.$ The reason for this is explained in the text. The problems related to non-Newtonian flows are discussed.

기판온도에 따른 ITO 박막의 제조 및 특성 (Preparation and characterization of ITO Thin Film By Various Substrate heating temperature)

  • 김성진;박헌균
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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    • pp.94.2-94.2
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    • 2010
  • Indium tin oxide (ITO) Thin films were grown on Non-alkarai glass Substrates by PVD method and Subsequently Subjected to ($100^{\circ}C-350^{\circ}C$) Thermal Annealing (TA) In Nitr Oxygen ambinent. Most of all, The effect of TA treatment on the structural properties were studied by using X-Ray diffraction and atomic force microscopy, while optical properties were studied by UV-Transmittance measurements. After TA treatment, the XRD spectra have shown an effective relaxation of the residual compressive stress, As a result, XRD peaks increase of the intensity and narrowing of full width at half-maximun (FWHM). In addtion The microstructure, The surface morphology, the optical transmittance changed and improved, and we investigated The effects of temperature, Time and atmosphere during the TA on the structural and electrical properties of the ITO/glass on TA at $300^{\circ}C$. As a results, the films are highly transparent (80%~89%) in visible region. AFM analysis shows that the films are very smooth with root mean square surface roughness 0.58nm -2.75nm thickness film. It is observed that resistivity of the films drcreases T0 $1.05{\times}10^{-4}{\Omega}cmt$ $6.06{\times}10^{-4}{\Omega}cm$, while mobility increases from $152cm^2/vs$ to $275cm^2/vs$.

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향요법마사지의 심리신경면역학적 효과 (Psychoneuroimmunologic Effect of Aromatherapy massage)

  • 이성희
    • 여성건강간호학회지
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    • 제6권2호
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    • pp.305-315
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    • 2000
  • The purpose of this study was to explore the psychoneuroimmunologic effect of aromatherapy massage and to compare the effect with that of massage. This study is designed as a nonequivalent control group pretest-posttest quasi-experimental study and each twenty postpartum mothers volunteered the experimental group and control group. For experimental group, researcher used massage with 2% Jojova oil mixed with Lavender and Rosemary oil (Bush Boake Allen Inc., USA) for 20 minutes, whereas for control group Jojova oil was used as luburicant for massage. Skin temperature was measured with YSI Tele-thermometer(Simpson electric Co., USA) and the concentration of IgA in salivary was analyzed by immunoturbididimetric assay(Cobas INTEGRA, Roche, Swiss) at pre and post test. Also at this time fatigue were measured by Rhoten Fatigue Scale through self-report. The data were analyzed using SAS and hypothesis was tested with unpaired t-test. The results were as follows : 1) Score of fatigue decreased significantly after use of aromatherapy massage. 2) Skin temperature increased significantly after use of aromatherapy massage. 3) Concentration of salivary IgA increased significantly after use of aromatherapy massage. In conclusion, from the standpoint of psychoneuroimmunologic view, the results suggest that aromatherapy massage have greater effect compared with massage and can be effective nursing intervention to enhance relaxation of mind and body in the postpartum mothers.

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