• 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 Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.216-221
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• 2017

Reducing optical reflection in the visible light range, in order to increase the share of transmitted light and avoid the formation of ghost images in imaging, is important for polymer lens applications. In this study, polymer lenses with refractive indices of n=1.56, 1.60, and 1.67 were fabricated by the injection-molding method with a polymer lens monomer, dibutyltin dichloride as the catalyst and an alkyl phosphoric ester as the release agent. To investigate their anti-reflection (AR) effects, various AR coating structures, viz. a multi-layer AR coating structure, tri-layer AR coating structure with a discrete approximation Gaussian gradient-index profile, and tri-layer AR coating structure with a quarter-wavelength approximation, were designed and coated on the polymer lens by an E-beam evaporation system. The optical properties of the polymer lenses were characterized by UV-visible spectrometry. The material properties of the thin films, refractive index and surface roughness, were analyzed by ellipsometry and AFM, respectively. The most effective AR coating structure of the polymer lens with low refractive index, n=1.56, was the both side coating of multi-layer AR coating structure. However, both side coating of the tri-layered discrete approximation Gaussian gradient-index profile AR coating structure gave comparable results to the both side coating of the multi-layer AR coating structure for the polymer lens with a high refractive index of n=1.67.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.482-487
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• 2016

Ultra-violet rays are very harmful to eye health care. The blocking of ultra-violet rays and a reduction of optical reflection in the visible light range, which is to increase the share of transmitted light, and avoid the formation of ghost images in imaging, are important for the applications of polymer eyeglasses lenses. In this study, the high-refractive index polymer lenses, n=1.67, were fabricated by injection-molded method with the xylene diisocyanate monomer, 2,3-bis-1-propanethiol monomer, and benzotriazol UV absorber (SEESORB 709) mixture. To reduce the reflection of the polymer lens surfaces, multi-layer anti-reflection (AR) coatings were coated for both sides of the polymer lens using an E-beam evaporation system. The optical properties of the UV blocking polymer lens were characterized using a UV-visible spectrometer. The material properties of the thin films, which were composed AR coating layers, refractive index, and surface roughness, were analyzed by ellipsometry and atomic force microscopy. As a result, the fabricated polymer lens perfectly blocked ultra-violet rays below 395 nm with a blocking rate greater than 99%.

• Conservation Science in Museum
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• v.17
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• pp.55-68
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• 2016

Conservation and research efforts are currently underway at the National Museum of Korea on a series of artifacts excavated from Tomb No. 9 at Seogam-ri nearly a century ago by an archaeology team from the institution's colonialera predecessor. Among these objects are a number of bronze and gilt bronze buttons. The present study explores the production techniques used in making such buttons. Both bronze and gilt bronze buttons are hemispherical in shape and are similar in external appearance. However, their shanks differ significantly in size and cross-sectional shape, some with a round cross-section while others are square. The buttons, first sorted into two groups by each type of shank, were further subdivided by size. Analysis of round shanks has found variations in design and location as well as in shank thickness. In addition, the location where round shanks attach to buttons are usually irregular in surface. Square shanks, on the other hand, are more uniform in design and location. The shanks are typically located on the backs of buttons and attach to a groove which ostensibly serves to mark the correct position. X-ray imaging has revealed that round shanks have thick borders made from metal rather than dirt or other material. The buttons themselves appear to been cast using lost-wax technique. The ways in which each shank attaches to its respective button varies based on its cross-sectional shape.

• Journal of Chest Surgery
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• v.41 no.6
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• pp.718-723
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• 2008

Background: The advances in surgical techniques, anesthesia management, perfusion methodology and postoperative intensive care have markedly decreased the mortality and cardiac morbidity of patients who undergo heart surgery over the past 2 decades. Nevertheless, it is well recognized that cardiac surgery carries a substantial risk for central nervous system complications. This study was conducted to evaluate the prevalence of subclinical cerebrovascular lesions in the head and neck by performing magnetic resonance angiography (MRA), and we investigated the clinical course of patients who had abnormal lesion seen on head and neck MRA. Material and Method: The subjects were 107 patients (71 men and 36 women ranging in age from 21 to 83 years) who were scheduled for cardiac surgery under nonemergency conditions between October 2005 and June 2008. Informed consent was obtained before the MRA. The carotid arteries, intracranial arteries and brain parenchyme were examined for subclinical cerebrovascular lesions by performing MRA. We reviewed the patients' medical records and MR findings to evaluate the prevalence of neurologically high risk patients and their clinical course. Result: The overall prevalence of neurologically high risk patients was 15.7% (17 patients). Among these patients, 11 patients had ischemic heart disease and 6 patients had valvular heart disease. Only 2 patients had a history of cerebrovascular disease. The clinical courses of 14 patients (13.1%) were changed according to their MRI findings. Conclusion: The prevalence of subclinical cerebrovascular disease in patients who were scheduled for cardiac surgery was higher than was expected. MR angiography was of value to identify these patients.

• Journal of the Korea Convergence Society
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• v.8 no.11
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• pp.115-121
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• 2017

The present study aimed to obtain basic knowledge of a customized artificial joint based on the convergence research of Digital Imaging and Communications in Medicine(DICOM) and 5-axis machining technology. In the case of the research method, three-dimensional modeling was generated based on the medical image of the humerus bone, and the shape was machined using a chemical wood material. Then, the anatomical characteristics and the modeling machining computation times were compared. The results showed that the Stereolithography (STL) modeling required twice more time for semi-finishing and 10 times more time for finishing compared to the Initial Graphics Exchange Specification(IGES) modeling. For the 5-axis machining humerus bone, the anatomical structures of the anatomic neck, greater tubercle, lesser tubercle, and intertubercular groove were similar to those in the three-dimensional medical image. In the future, the convergence machining technology, where 5-axis machining of various structures(e.g., the surgical neck undercut of the humerus bone) is performed as described above, can be efficiently applied to the manufacture of a customized joint that pursues the precise model of a human body.

• Journal of the Korea Institute of Building Construction
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• v.16 no.1
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• pp.35-43
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• 2016

Concrete is a representative heterogeneous material and mechanical properties of concrete are influenced by various factors. Due to the fact that pores in concrete affect determining compressive strength of concrete, studies which deal with distribution and magnitudes of pores are very important. That way, studies using picture imaging have been emerged. Studies on mechanical performance evaluation of structural lightweight foamed concrete and FEM analysis based on picture image are inadequate because lightweight foamed concrete has been researched for only non-structural. Therefore, in this study, cement paste with foaming agent to evaluate mechanical performance is made, FEM analysis with picture image is conducted and young's modulus of experiment and analysis are compared. In this study, dosage of foaming agent is determined 7 level to check pore distribution and water-binder ratio is determined 20% to progress research about structural light weight foamed concrete. Weight of unit volume is minimum at 0.8% of foaming agent dosage. However, weight of unit volume is increased over 0.8% of foaming agent dosage because of interconnection with independent pores. For FEM analysis, cement paste is photographed to use image analyzer(HF-MA C01). Consequently, the fact that Young's Modulus of experiment and FEM analysis are same is drawn by using OOF(Object Oriented Finite elements).

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.44 no.3
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• pp.112-119
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• 2018

Objectives: Temporomandibular joint ankylosis (TMJA) is a joint pathology caused by bony and/or fibrous adhesion of the joint apparatus, resulting in partial or total loss of function. Materials and Methods: This is a retrospective study conducted between 2012 and 2016 in the northwest region of Nigeria. The data retrieved includes gender, age, etiology of ankylosis, duration of ankylosis, laterality of ankylosis, type of imaging technique, type of airway management, types of incision, surgical procedure, mouth opening, interpositional materials used, and complications. Results were presented as simple frequencies and descriptive statistics. Results: Thirty-six patients with TMJA were evaluated during the study period. There were 21 males (58.3%) and 15 females (41.7%), yielding a male:female ratio of 1.4:1. The patients' age ranged from 5 to 33 years with $mean{\pm}standard$ deviation ($13.8{\pm}6.6years$). Thirty-five cases (97.2%) were determined to be true/bony ankylosis, while only 1 case (2.8%) was false/fibrous ankylosis. Most of the TMJA cases (16 cases, 44.4%) were secondary to a fall. In our series, the most commonly utilized incision was the Bramley-Al-Kayat (15 cases, 41.7%). The mostly commonly performed procedures were condylectomies and upper ramus ostectomies (12 cases each, 33.3%), while the most commonly used interpositional material was temporalis fascia (14 cases, 38.9%). The complications that developed included 4 cases (11.1%) of severe hemorrhage, 1 case (2.8%) of facial nerve palsy, and 1 case (2.8%) of re-ankylosis. Conclusion: Plain radiographs, with their shortcomings, still have significant roles in investigating TMJA. Aggressive postoperative physiotherapy for a minimum of 6 months is paramount for successful treatment.

• 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.

• Journal of Magnetics
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• v.19 no.3
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• pp.248-254
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• 2014

The purpose of this study is to figure out how uptake counts of technetium ($^{99m}Tc$) among radioisotopes in the human body are affected if computed tomography (CT), magnetic resonance imaging (MRI) and isotope examination are performed consecutively. $^{99m}Tc$ isotope material, iodinated contrast media for CT and paramagnetic contrast media for magnetic resonance (MR) were used as experimental materials. First, $^{99m}Tc$ was added to 4 cc normal saline in a test tube. Then, 2 cc of CT contrast media such as $Iopamidol^{(R)}$ and $Dotarem^{(R)}$ were diluted with 2 cc normal saline, and 2cc of MRI contrast media such as $Primovist^{(R)}$ and $Gadovist^{(R)}$ were diluted with 2 cc normal saline. Each distributed contrast media was a total of 4 cc and included 10m Ci of $^{99m}Tc$. A gamma camera, a LEHR (Low energy high resolution) collimator and a pin-hole collimator were used for image acquisition. Image acquisition was repeated a total of 6 times and 120 frames were obtained and uptake counts of $^{99m}Tc$ were measured (from this procedure). In this study, as a result of measuring the uptake counts of $^{99m}Tc$ using the LEHR collimator, the uptake counts were less measured in all contrast media than normal saline as a reference. In particular, the lowest uptake counts were measured when $Gadovist^{(R)}$, contrast media for MRI, was used. However, the result of measuring the uptake counts of $^{99m}Tc$ using the pin-hole collimator showed higher uptake counts in all contrast media, except for $Iopamidol^{(R)}$, than normal saline as a reference. The highest uptake counts were measured particularly when $Primovist^{(R)}$, contrast media for MRI, was used. In performing the gamma camera examination using contrast media and $^{99m}Tc$, it is considered significant to check the changes in the uptake counts to improve various diagnosis values.