• The Journal of the Korea Contents Association
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• v.17 no.7
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• pp.437-442
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• 2017

Previously, studies on compensation material to increase the signal intensity have been conducted which does not affect the reading of images. However, the compensation material has a concern on patient infection as it is attached directly on the skin. Therefore, in this study, we tested an indirect attachment of the compensation material as an alternative method of the direct attachment. The silicon compensation material was fabricated in the form of a cylindrical bar and attached to each element of the 8 channel head coil. Then the signal intensities of the water phantom pre and post application of the silicon were measured. T1 and T2-weighted images were acquired using an 8-channel head coil and a 3.0T superconducting MRI. Signal intensities were measured by using an image measuring program. Paired t-test was used to verify if there were significant differences. The signal intensity before application of the silicon was significantly increased by 3.39% and 2.62% in T1 and T2 weighted images, respectively. Although the indirect attachment method had a limitation to completely replace the existing method, it was considered to be useful in patients with infectious diseases such as diabetic complications since it had a meaningful improvement in signal intensity based on the filling factor increase.

• Journal of Korean Neurosurgical Society
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• v.29 no.10
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• pp.1316-1321
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• 2000

Objectives : The authors analyzed the surgical series of Cushing's disease to evaluate the proper treatment policy and to verify the possible prognostic factors. Material and Methods : Of 50 patients diagnosed as Cushing's disease and operated at Department of Neurosurgery of our institute between 1988 and 1999, 48 patients with available medical records were analyzed retrospectively. Mean follow-up period was 48 months(3 to 109 months). Preoperative diagnosis was made after evaluating the patients with multiple-stage endocrinological studies and 31 selective patients were evaluated with inferior petrosal sinus sampling(IPSS). Magnetic resonance imaging(MRI) and/or high resolution computerized tomography(CT) was done in all patients. A total of 51 transsphenoidal adenomectomy(TSA) were performed including 3 revision for initial surgical failure cases. Remission was decided on the basis of both endocrinological criteria and clinical status. Radiation and/or ketoconazole therapy were applied to failed cases. For the verification of prognostic factors, the authors evaluated the statistical significance of multiple variables over remission rate by chi-square test. Result : Sensitivity of IPSS for central localization was 93.5% which was better than that of MRI(87.5%). But for lateralization, it was 72.4% for IPSS versus MRI 90.5%. Success rate of TSA was 82%(42/51) and recurrence rate was 9%(4/48). When including adjuvant treatments for surgically failed cases, overall success rate was 89.6% and all of 3 reoperated cases(TSA) due to recurrence were successful. Significant complication occurred in 7.8%(4/51) after TSA including hypopituitarism, diabetes insipidus, and visual loss. Non-existence of tumor in MRI and prolonged symptom duration(>3 years) were significant prognostic factors. Conclusion : TSA can be considered as initial treatment for Cushing's disease. In surgically failed cases, multiple treatment modality may improve the overall outcome and repeated TSA for recurrent cases seem to provide similar success.

• Journal of the Korean Vacuum Society
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• v.15 no.4
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• pp.331-337
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• 2006

Cavity-type beam position monitors were developed in collaboration with KEK to use for the future accelerators such as international linear collider (ILC) or x-ray free electron laser (XFEL) in PAL. BPM components such as BPM cavity, beam tubes, waveguides and feedthroughs were assembled by brazing at the same time to reduce mechanical errors during the fabrication. There are four screwed pins around outer rim of the cavity for the tuning of cavity frequency and x-y isolation. The resonance frequency of BPM is 6.422 GHz, the inner diameter of cavity is 53.822 mm, and the range of mechanical adjusting is $+ / - 250{\mu}m$. The x-y isolation was measured better than -40 dB after tuned. Test results of signal forms, x-y isolations, sensitivities are satisfied within requirements for the KEK ATF2 beam line.

• Journal of the Korean Geotechnical Society
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• v.27 no.5
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• pp.85-92
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• 2011

The dynamic behavior of piles becomes very complex due to soil-pile dynamic interaction, soil non-linearity, resonance phenomena of soil-pile system and so on. Therefore, the proper numerical simulation of the pile behavior needs much effort and calculation time. In this research, a new modeling method, which can be applied to the conventional finite difference analysis program FLAC 3D, was developed to reduce the calculation time. The soil domain in this method is divided into a near-field region and a far-field region, which is not influenced by the soil-pile dynamic interaction. Then, the ground motion of the far-field is applied to the boundaries of the near-field instead of modeling the far-field region as finite meshes. In addition, the soil non-linearity behavior is modeled by using the hysteretic damping model, which determines the soil tangent modulus as a function of shear strain and the interface element was applied to simulate the separation and slip between the soil and pile. The proposed method reduced the calculation time by as much as one third compared with a usual modeling method and maintained the accuracy of the calculated results. The calculated results by the proposed method showed a good agreement with the prototype pile behavior, which was obtained by applying a similitude law to the 1-g shaking table test results.

• Journal of the Korean earth science society
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• v.32 no.1
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• pp.1-11
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• 2011

The impact echo and impulse response methods were applied to the safety inspection of concrete structure, which has the rear cavity. The concrete structure model used in this study was divided into four sections, pure concrete, concrete+cavity, reinforced concrete with iron bar, and reinforced concrete+cavity, respectively. Previous study performed by authors have showed a possibility of success to use these method for detection of the rear cavity of concrete structure. Therefore, we tried to get more enhanced result with IE and IR methods through this study. Especially, IE and IR methods are relatively accurate to map the point of measurement, which makes it possible to interpret the depth of the concrete bed and effect by rear cavity with confidence. Followings were revealed from the results; the IE method shows some small peak zones probably indicating the rear cavity in the frequency lower than the resonance frequency and the changes of mobility and dynamic stiffness in the IR method indicate the weak zones. The proposed methods can be used to delineate the weak zones of the concrete structure.

• Tuberculosis and Respiratory Diseases
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• v.60 no.3
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• pp.353-356
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• 2006

Acute transverse myelitis (TM) is a neurological syndrome caused by inflammation of the spinal cord. TM is rare but is frequently caused by viral or bacterial infections. TM caused by tuberculosis (TB) is extremely rare and there are no reports of TM caused by multidrug-resistant TB (MDR-TB). We report a case of acute TM due to MDR-TB in a 40-year-old man. The patient had been diagnosed with pulmonary TB and was started on the first-line anti-TB treatment. However, the chest radiographic findings were aggravated and neurological symptoms such as weakness in both lower extremities, sensory changes, and voiding difficulty were newly developed. The T2-weighted magnetic resonance image of the spine showed diffusely increased signal intensity in the spinal cord, particularly at the lower cervical and upper thoracic levels, without any definite evidence of myeloradicular compression, which is consistent with a diagnosis of TM. A drug susceptibility test revealed MDR and second-line anti-TB drugs were prescribed. The chest radiographic findings showed improvement after treatment, the mycobacterial culture converted to negative, the MRI findings improved, and there was partial improvement in the low extremity weakness. The patient has been prescribing second-line anti-TB medications for 14 months.

• Korean Journal of Biological Psychiatry
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• v.22 no.4
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• pp.223-232
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• 2015

Objectives In this study, the authors evaluated the correlation between levels of serum lipid, homocysteine, and folate with volumes of hippocampus, amygdala, corpus callosum, and in patients with amnestic mild cognitive impairment (aMCI) or Alzheimer's disease (AD) type. Methods The study recruited patients who visited the dementia clinic of Haeundae Paik Hospital in Korea between March 2010 and June 2014. Among those, patients who had taken the neurocognitive test, brain magnetic resonance imaing, tests for serum lipid, homocysteine, folate, and apolipoprotein E (APOE) genotyping and diagnosed with aMCI or AD were included for analysis. Bilateral hippocampus, entorhinal cortex, amygdala and corpus callosum were selected for region of interest (ROI). The cross-sectional relationships between serum lipid, homocysteine, folate and ROI were assessed by partial correlation analysis and multiple linear regression analysis. Results In patients with aMCI, old age (> 80) and APOE ${\varepsilon}4$ carrier were associated with AD [odds ration (OR) : 12.80 ; 95% confidence interval (CI) : 2.25-72.98 and OR : 4.48 ; 95% CI : 1.58-12.67, respectively]. In patients with aMCI or AD, volumes and thickness of ROI were inversely correlated with levels of serum lipid and homocysteine. In multiple linear regression analyses, higher total cholesterol level was related to lower left, right hippocampus volume and left amygdala volume ; higher low-density lipoprotein cholesterol was related to lower right entorhinal cortex thickness ; higher homocysteine level was related to lower corpus callosum volume. Conclusions Higher serum lipid and homocysteine levels are associated with decreased volume of hippocampus, amygdala, corpus callosum and entorhinal cortex thickness in patients with aMCI or AD. These findings suggest that serum lipid and homocysteine levels are associated with AD as a modifiable risk factor.

• Progress in Medical Physics
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• v.7 no.2
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• pp.67-77
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• 1996

Purpose: To get a 3-D coordinates of intracranial target position was investicated in axial, sagittal and coronal magnetic resonance imaging with a preliminary experimented target localizer. Material and methods : In preliminal experiments, the localizer is made of engineering plastic to avoid the distrubance of magnetic field during the MR image scan. The MR localizer displayed the 9 points in three different axial tomogram. The bright signal of localizer was obtjained from 0.1～0.3％ of paramagnetic gadolinium/DTPA solution in T1WI or T2WI. In this study, the 3-D position of virtual targets were examined from three different axial MR images and the streotactic position was compared to that of BRW stereotactic system in CT scan with same targets. Results: This study provided the actual target position could be obtained from single scan with MRI localizer which has inverse N-typed 9 bars. This experiment was accomplished with shimming test for detection of image distortion in MR image. However we have not found the image distortion in axial scan. The maximum error of target positions showed 1.0 mm in axial, 1.3 mm for sagittal and 1.7 mm for coronal image, respectivelly. The target localization in MR localizer was investicated with spherical virtual target in skull cadaver. Furthermore, the target position was confirmed with CRW stereotactic system showed a 1.3 mm in discrepancy. Summary : The intracranial target position was determined within 1.7 mm of discrepancy with designed MR localizer. We found the target position from axial image has more small discrepancy than that of sagittal and coronal image.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.137-137
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• 2001

Purpose： The purpose of this study was to identify cerebral cortices related with sexual arousal fro visual sexual stimulation in healthy males using BOLD-based functional MR imaging Method： Sixteen male volunteers with sexually potent(mean age：24) were examined for thi study. Functional MRI was performed on a 1.5T MR scanner(GE Signa Horizon) with birdcage-type head coil. In this study, blood oxygenation level dependent(BOLD) technique was utilized to create fMR image reflecting local brain activities. The BOLD-based fMRI d were obtained from 7 oblique planes using gradient-echo EPI with $90^{\circ}$flip angle, 50ms TE 6000ms TR, $26cm{\times}26$ cm FOV, $128{\times}128$ matrix, and 10mm slice thickness. The sexual stimulation paradigm consisted of two alternating periods of rest and activati and it began with a 1 minute rest, followed by a 2 minute stimulation by a documentary a erotic video film. Brain activation maps were generated by cross-correlation of imag acquired during rest and activation periods. The index of activation was used to compare t number of pixels activated by each task in each volunteer, where the significance of th differences was evaluated by using Students t-test.

• Journal of Gifted/Talented Education
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• v.23 no.5
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• pp.637-648
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• 2013

The relationship between the cerebral cortex and human intelligence has been studied using various methods, and related brain areas involved in intellectual manifestation have been discovered individually. Such studies have also shown the cerebellum is closely involved in various cognitive functions such as language, memory, and information processing. However, studies showing an activity difference between the cerebral cortex and cerebellum when performing specific tasks are hard to find. This study searched and analyzed the active regions of the cerebral cortex and cerebellum seen while performing the inference of geometrical figures. A WAIS intelligence test was conducted using 81 healthy boys (16.3 years of age on average), and five categories were classified. While performing the inference of shapes, their brain images were taken using functional magnetic resonance imaging (fMRI). As a result, the activity in 12 brain regions was observed, including in the cerebral cortex, the bilateral inferior parietal, the visual cortex, bilateral superior parietal, frontal-Inf-Tri-R, and bilateral caudate, while activities in 5 discrete areas were seen in the cerebellum. In particular, the higher the intelligence (IQ) of the subject, the stronger their activity. Among those with the most superior intelligence, subjects with an IQ of 140-147 showed significantly higher activity compared to the other groups. Such results seem to represent a very high utilization of intelligence in a highly gifted group, and we can expect to use this to determine the super gifted.