• Investigative Magnetic Resonance Imaging
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• v.23 no.4
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• pp.341-350
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• 2019

Purpose: To determine the MR parameters affecting India ink artifacts on opposed-phase chemical shift magnetic resonance (MR) imaging. Materials and Methods: The use of a female Sprague-Dawley rat was approved by our Institutional Animal Care and Use Committee. Using an iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) images, which is a modified Dixon method, axial opposed-phase images of the abdominal cavity were obtained with different MR parameters: series 1, different repetition times (TRs; 400, 2000, and 4000 ms); series 2, different echo times (TEs; 10, 50, and 100 ms); series 3, different field of views (FOVs; 6, 8, 16, and 24 cm); series 4, different echo train lengths (ETLs; 2, 4, and 8); series 5, different bandwidths (25, 50, and 85); and series 6, different slice thicknesses (1, 2, 4, 8, and 16 mm). Artifacts on opposed images obtained with different parameters were compared subjectively by two radiologists. For objective analysis, the thickness of the artifact was measured. Spearman's correlation between altered MR parameters and thicknesses of India ink artifact was obtained via objective analysis. Results: India ink artifact was increasingly apparent using shorter TE, larger FOV and ETL, and thicker slices upon subjective analysis. The objective analysis revealed a strong negative correlation between the thickness of the artifact and TE (r = -0.870, P < 0.01); however, strong positive correlations were found between FOV (r = 0.854, P < 0.01) and slice thickness (r = 0.971, P < 0.01). Conclusion: India ink artifact was thicker with shorter TE, larger FOV, and larger slice thickness.

• Journal of radiological science and technology
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• v.26 no.3
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• pp.33-39
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• 2003

Purpose : Be aware of clinical possibilities on image quality by comparison of contrast-enhanced dynamic CT and MR imaging applied of MIP technique after the experimentally induced clonorchasis infection in dogs. Materials and Method : Twenty mongrel dogs prepared in zoo-laboratory were followed up with serial CT scans and MR imaging for 13 weeks after the experimental infection in liver. Two-phase helical CT was acquired in the supine position with the following scanning parameters. After the injection of contrast material, the arterial phase was initiated using a bolus-racking method. The portal phase scan was started 15 seconds after the arterial phase scan. CT protocol was determined after single level dynamic scans. MR imaging used the CP body coil and images get a 2D image using HASTE, FLASH, TSE pulse sequence. Bile duct MR imaging were obtained in three plans. Then each image was post processed by using target MIP algorithm. Two experimentation above, as a method of evaluation, one pathologist, three radiologist and five radiological technologist were analyzed visually for evaluation of following findings, enhancement of the bile duct wall, dilatation of bile duct tip, liver parenchyma, background suppression. Results : Five dogs was died of a disease after the infection, the rest one else shows the chronic dilatation of the intrahepatic bile duct with CT and MR imaging. Contrast administration of CT shows the contrast-enhanced of the bile duct walls with live parenchyma. MR imaging calculated of CNR and CR from pulse sequence for comparative evaluation and shows the pattern of the intrahepatic bile duct, dilatation of bile duct tip using MIP technique. CNR of the clonorchiasis, HASTE was $16{\pm}0.83$, TSE $7.06{\pm}3.0$, FLASH $1.19{\pm}0.2$ and CR, HASTE was 73.3%, TSE 62.3%, FLASH 6.4%. Conclusion : CT and MR imaging is very usefulness in diagnosis of dog clonorchiasis.

• Clinics in Shoulder and Elbow
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• v.3 no.2
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• pp.95-101
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• 2000

Purpose : The purpose of this study was to evaluate the efficacy of oblique coronal MR images, oblique axial images of neutral, internal rotation and external rotation positions in the diagnosis of SLAP Ⅱ lesion. Materials and Methods: MR arthrography of the glenohumeral joint was evaluated retrospectively in 16 patients(16 shoulders) who underwent arthroscopic surgery(mean age; 38 years old, Male; 13, Female; 3). Oblique coronal fat-suppressed Tl-weighted spin echo images were performed with each shoulder in the neutral position of the arm and oblique axial images were performed in neutral, internal and external rotations of the arm respectively. The preoperative findings of MR were classified as definite tear, possible tear and no tear. Arthroscopic findings were correlated with MR findings of several different position of the arm. Results: Arthroscopic surgery revealed 8 SLAP Ⅱ lesion, 2 SLAP I lesion, and 6 normal superior labrum respectively. The accuracy of diagnosis in the 8 SLAP Ⅱ lesion were high on oblique axial image in external rotation which were interpreted as 8 definite tear, to compare with oblique axial images in neutral position which were interpreted as 4 definite tear, 3 possible tear, 1 no tear. The 6 normal superior labrum lesion were interpreted as no tear in all three position. The 2 SLAP I lesion were interpreted as 1 definite tear, 1 no tear on oblique axial image in neutral position and 1 definite tear, 1 possible tear on oblique axial image in external rotation. Conclusion: This study showed that axial MR images in external rotation of the arm combined with oblique coronal images have proved to be effective to detect SLAP Ⅱ lesion, and should be considered in imaging protocol for MR arthrography of the SLAP Ⅱ lesion.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.3
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• pp.60-66
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• 2012

This paper aims to constitute a feedback vibration control system using wireless sensor networks and experiment it on a model structure to verify its effectiveness. For the purpose, we set up a feedback vibration control system composed of a wireless input/output(I/O) sensor node based on bluetooth, a home-made shear type MR damper, a shaker which generates a constant size of sine wave, and a simple beam model structure. The vibration control experiment was performed by shaking the 1/4 point of beam with a shaker. At the moment of shaking, we controled the vibration with MR damper which was placed vertically on the center of beam. Simultaneously, by acquiring acceleration response at the 2/4 point of beam, we evaluated the effectiveness of control capability. The control command was set to send a voltage signal to MR damper when the acceleration response, acquired from the wireless I/O sensor node placed at the center of beam, was more than a certain amount. Although the realtime feedback vibration control system constituted in this paper is effective only within a limited command system, it has been proven that the system was able to effectively decrease the vibration of structure by generating a control command aimed for realtime purpose. The system also showed a possibility to be used as a structural response control system adapting a variety of semi-active control algorithm.

• Transactions on Electrical and Electronic Materials
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• v.15 no.4
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• pp.230-234
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• 2014

Automatic detection of disease helps medical institutions that are introducing digital images to read images rapidly and accurately, and is thus applicable to lesion diagnosis and treatment. The aim of this study was to apply a symmetry contribution algorithm to unsharp mask filter-applied MR images and propose an analysis technique to automatically recognize brain tumor and edema. We extracted the skull region and drawed outline of the skull in database of images obtained at P University Hospital and detected an axis of symmetry with cerebral characteristics. A symmetry contribution algorithm was then applied to the images around the axis of symmetry to observe intensity changes in pixels and detect disease areas. When we did not use the unsharp mask filter, a brain tumor was detected in 60 of a total of 95 MR images. The disease detection rate for the brain was 63.16%. However, when we used the unsharp mask filter, the tumor was detected in 87 of a total of 95 MR images, with a disease detection rate of 91.58%. When the unsharp mask filter was used in the pre-process stage, the disease detection rate for the brain was higher than when it was not used. We confirmed that unsharp mask filter can be used to rapidly and accurately to read many MR images stored in a database.

• Microbiology and Biotechnology Letters
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• v.23 no.6
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• pp.641-646
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• 1995

During the screening of inhibitors of melanin biosynthesis from microbial secondary metabolites, a fungal strain MR304 which was capable of producing high level of an inhibitor was selected. Based on taxonomic studies, this fungus could be classified as Trichoderma harzianum. The active compound (MR304-1) was purified from culture broth by Diaion HP-20 column chromatography, ethylacetate extraction, Sephadex LH-20 column chromatographv and HPLC. The inhibitor was identified as 3-(1,5-dihvdroxy-3-isocyanocyclopent-(E)-3-envl)prop-2-enoate by spectroscopic methods of UV, ESIMS, $^{1}$H-NMR, $^{13}$C-NMR, NOE, HMQC and HMBC. MR304-1 showed strong mushroom tyrosinase inhibitory activity with IC$_{50}$ value of 0.25 $\mu $g/ml. It inhibited melanin biosynthesis with 15 mm inhibition zone at 30 $\mu $g/paper disc in Streptomyces bikiniensis, a bacterium used as an indicator organism in this work. It also inhibited melanin biosynthesis in B16 melanoma cells with a niinimum inhibitory concentration of 0.05 $\mu $g/ml.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.2
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• pp.291-304
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• 1994

The purpose of this study was to analyze the facial asymmetry of the patients with the craniomandibular disorder. In this study, 50 patients, who have joint clicking and pain, mouth opening limitation, and 40 dental students, Chosun University, who did not posses any restoration and orthodontic treatment, joint clicking and pain, mouth opening limitation, were selected as the control group. Both the control group and the patient group were takened skull P-A, submento-vertex radiogram by standized methods. After that, the deviation and facial asymmetry were measured and analyzed. The results of the this study were as follows: 1. In the Skull P-A radiogram, the width difference of control group and patient group measured that the △ Cg-Go-Cl: control group were 3.35㎜, patient group were 4.51㎜ (P<0.05), the △Cg-Zy-Go: control group were 1.83㎜, patient group were 3.27㎜(P<0.001). 2. In the Skull P-A radiogram, the height difference of control group and patient group measured that the △ Cg-Go-Cl: control group were 131.85㎜, patient group were 188.45㎜(P<0.05), the △Cg-Zy-Go: control group were 1.58㎜, patient group were 2.68㎜(P<0.00l). 3. In the Skull P-A radiogram, the area difference of control group and patient group measured that the △ Cg-Go-Cl: control group were 120.76㎟, patient group were 185.49㎟(P<0.05), the △Cg-Zy-Go: control group were 2.29㎟, patient group were 3.37㎟(p<0.05). 4. In the submento-vertex radiogram, the width difference of control group and patient group measured that the △Mr-Cl-Ia: control group were 1.50㎜, patient group were 2.35㎜(P<0.05), the △Mr-Cm-Ia: control group were 1.75㎜, patient group were 3.17㎜(P<0.05), the △Mr-Go-Ia: control group were 1.96㎜, patient group were 3.24㎜(P<0.001), the △Mr-Cp-Co: control group were 1.74㎜, patient group were 2.73㎜(P<0.05). 5. In the submento-vertex radiogram, the height difference of control group and patient group measured that the △Mr-Cp-Ia: control group were 1.68㎜, patient group were 2.46㎜P<0.05), the △Mr-CI-Ia: control group were 2.38㎜, patient group were 3.74㎜(P<0.05), the △Mr-Co-Ia: control group were 1.63㎜, patient group were 2.80㎜(P<0.05), the △Mr-Cm-Ia: control group were 1.45㎜, patient group were 3.12㎜(P<0.001). 6. In the submento-vertex radiogram, the area difference of control group and patient group measured that the △ Mr-Cp-Ia: control group were 73.17㎟, patient group were 110.16㎟(P<0.05), the △Mr-Cl-Ia: control group were 105.09㎟, patient group were 180.87㎟(P<0.001), the △Mr-Co-Ia: control group were 103.31㎟, patient group were 148.48㎟(P<0.05), the △Mr-Cm-Ia: control group were 97.01㎟, patient group were 167.83㎟(P<0.05), the △Mr-Go-Ia: control group were 104.24㎟, patient group were 205.90㎟(P<0.05).

• Computational Structural Engineering
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• v.16 no.3
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• pp.41-50
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• 2003

• Journal of KSNVE
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• v.16 no.6 s.84
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• pp.36-41
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• 2006

• Journal of KSNVE
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• v.16 no.5 s.83
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• pp.66-72
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• 2006