• 구강회복응용과학지
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• 제23권4호
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• pp.373-384
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• 2007

The purpose of this study was to analyse the stress distribution on the craniofacial suture and cranium after application of RME. Twelve years and six months old boy and twenty years old adult male were chosen for taking computed-tomography for FEM. From DICOM visual information, it was processed by 3-dimensional image construction program Mimics 10.01. Hounsfield unit(HU) which shows gray scale of CT image is picked for revealing mechanical properties of each model. The models have been accomplished with various range of physical properties. After applying 5.0 mm expansion, the maxillary complex model was obeserved for analyzing displacement and stress distribution of the model. The amount of transverse expansion of child and adult maxilla is different according to its location. It appears that it decreases gradually with the distance from separation site. In child, maximum compressive stress located broad area in zygomatic buttress department and the ends of frontal process of maxilla, pterygoid plate, and bones surrounding orbit. However, in adult maximum compressive stress was located smaller area and the stres was higher than child.

• 대한기계학회논문집B
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• 제29권1호
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• pp.103-109
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• 2005

Airflow in the nasal cavity of a normal Korean adult is investigated experimentally by tomographic PIV measurement. Knowledge of airflow characteristics in nasal cavities is essential to understand the physiology and pathology aspects of nasal breathing. Several studies have utilized physical models of the healthy nasal cavity to investigate the relationship between nasal anatomy and airflow. All of these researches on nasal airflow are under the condition of constant flow-rate. In this study, nasal cavity flow with the physiological period is investigated by tomographic PIV, for the first time. A pumping system that can produce the periodic flow is created. Thanks to a new method for the model casting by a combination of the rapid prototyping and curing of clear silicone, a transparent rectangular box containing the complex nasal cavity can be made for PIV, The CBC PIV algorithm is used for analysis. Phase-averaged mean and RMS velocity distributions are obtained for inspirational and expiration nasal airflows. The comparison with the constant flow case is appreciated. There exist many flow patterns depending on each phase.

• 대한정형도수물리치료학회지
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• 제16권1호
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• pp.64-76
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• 2010

The sacroiliac joint is difficult to appropriately examine and treat because it is extremely complex and also is difficult to distinguish dysfunctions from those of the spine and hip which are highly intergrated functionally. In addition generally traditional x-rays and CT scans also are not beneficial in detecting sacroiliac joint dysfunction. The manipulative physiotherapist should seek to establish a series of relevant finding that build into a case implicating the sacroiliac joint. When deciding to use these diagnostic tests, the examiner must determine if the test will give reliable and useful information that will help in the diagnosis and subsequent treatment. To be useful diagnostic tests must give reliable data and be valid and the most useful methods of determining whether a test is a good test for pathology under consideration are sensitivity and specificity. In the ideal world, one would want a test that has both high sensitivity and high specificity. The purpose of this review is to ascertain diagnostic value on the tests for sacroiliac joint dysfunction by literature.

• Design & Manufacturing
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• 제11권3호
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• pp.29-34
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• 2017

Increased demand for parts with micro-pattern structure made of metals, ceramics, and composites in various fields such as medical ultrasonic sensors, CT collimators, and ultra-small actuator parts. Micro powder injection molding (PIM) is a technology for manufacturing micro size, high volume, complex, precision, net-shape components from either metal or ceramic powder. In the present study, a standard mold with a variable insert core capable of producing various micro patterns was investigated. An injection molding test was performed on a standard mold using a line type micro-pattern core having an aspect ratio of 2, a slenderness ratio of 70, a pattern size of $200{\mu}m$, and a pattern spacing of $150{\mu}m$. During the filling process, the deformation of the mold with large aspect ratio and slenderness ratio was analyzed by the experiment and the numerical simulation according to the position of the gate. We proposed a mold structure that minimizes mold deformation by gate modification and enables uniform pattern filling behavior.

• 한국재료학회지
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• 제27권12호
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• pp.688-694
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• 2017

Porous materials such as polymeric foam are widely adopted in engineering and biomedical fields. Porous materials often exhibit complex nonlinear behaviors and are sensitive to material and environmental factors including cell size and shape, amount of porosity, and temperature, which are influenced by the type of base materials, reinforcements, method of fabrication, etc. Hence, the material characteristics of porous materials such as compressive stress-strain behavior and void volume fraction according to aforementioned factors should be precisely identified. In this study, unconfined uniaxial compressive test for two types of closed-cell structure polyurethane foam, namely, 0.16 and $0.32g/cm^3$ of densities were carried out. In addition, the void volume fraction of three different domains, namely, center, surface and buckling regions under various compressive strains (10 %, 30 %, 50 % and 70 %) were quantitatively observed using Micro 3D Computed Tomography(micro-CT) scanning system. Based on the experimental results, the relationship between compressive strain and void volume fraction with respect to cell size, density and boundary condition were investigated.

• 대한핵의학회지
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• 제34권4호
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• pp.366-369
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• 2000

We report a case of a patient with cystic subdural hygroma who underwent pre-operative Tc-99m DTPA cistrenoscintigraphy to determine the course of operation. A 68-year-old female was admitted to the department of neurosurgery because of acute subarachnoid hemorrhage. After emergency ventricular drainage, the hydrocephalus and cystic subdural hygroma in the right fronto-temporal area developed. She underwent Tc-99m DTPA cisternoscintigraphy to evaluate the type of hydrocephalus, which revealed obstructive communicating hydrocephalus and the communication between the subdural hygroma and the subarachnoid space. As a result of these findings, she underwent the ventriculo-peritoneal shunt operation without removal of the subdural hygroma. Post-operative brain CT showed nearly normalized shape and size of the right ventricle and disappearance of subdural hygroma. We recommend the pre-operative cisternoscintigraphy in patients with complex hygroma to evaluate the communication between subdural hygroma and the subarachnoid space.

• Parasites, Hosts and Diseases
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• 제60권6호
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• pp.413-417
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• 2022

We retrospectively evaluated the clinical and imaging features of 6 patients with bone hydatid disease confirmed by surgery and pathological examination. Among the 6 patients, 2 were infected with Echinococcosis granulosus metacestode and 4 were infected with E. multilocularis metacestode. The 2 cases with cystic echinococcosis were diagnosed by computed tomographic (CT) examination, and other 4 cases were diagnosed by magnetic resonance (MR) imaging. On the initial evaluation, 1 case each was misdiagnosed as a giant cell tumor or neurogenic tumor, and 2 were misdiagnosed as tuberculosis. The imaging manifestations of bone hydatid disease are complex, but most common findings include expansive osteolytic bone destruction, which may be associated with sclerosing edges or dead bone formation, localized soft tissue masses, and vertebral lesions with wedge-shaped changes and spinal stenosis. Combining imaging findings with the patient's epidemiological history and immunological examinations is of great help in improving the diagnosis and differential diagnosis of bone hydatid disease.

• 대한영상의학회지
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• 제82권2호
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• pp.417-422
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• 2021

제1형 신경섬유종증은 상염색제 우성으로 유전되는 신경외배영성 질환으로 다양한 악성 종양이 발생할 수 있다. 하지만 유방암이 발생한 보고는 드물다. 이에 저자들은 제1형 신경섬유종증 환자에서 발생한 양측성 유방암 증례를 영상 소견과 함께 보고하고자 한다.

• Tuberculosis and Respiratory Diseases
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• 제57권3호
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• pp.242-249
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• 2004

연구배경 : 기관지확장증을 가진 환자의 객담에서 NTM이 분리되는 경우 집락상태와 폐침범을 구별하는 것은 쉽지 않다. 본 연구는 기관지확장증과 다발성 결절이 관찰되는 환자에서 NTM 폐질환을 진단하는데 기관지 내시경술의 유용성을 알아보고자 하였다. 대상 및 방법 : 2002년 4월부터 2003년 6월까지 흉부 전산화단층촬영에서 기관지확장증과 동반된 다발성 결절로 NTM 폐질환이 의심되어, 기관지내시경을 통해 기관지폐포세척술과 경기관지폐생검을 시행한 48명의 환자를 대상으로 후향적 조사를 시행하였다. 결 과 : 48명의 환자 중 여자가 34명(71%)이었고, 연령은 중앙값 60세(범위 21-80세)였다. 최종진단은 NTM 폐질환 26명(54%; M. abscessus 14명, MAC 12명), 기관지 확장증에 동반된 비특이적 세기관지염 15명(31%), 폐결핵 3명(6%) 등이었다. 기관지내시경 시행 전 객담에서 3회 이상 NTM이 분리된 환자 21명 중 6명(29%)에서 경기관지폐생검 조직 도말 양성, 14명(67%)에서 조직 배양 양성, 5명(24%)에서 육아종이 관찰되어 전체적으로 16명(76%)에서 NTM 폐 침범의 소견을 확인하였다. 객담검사만으로 NTM 폐질환을 진단하지 못한 27명의 환자 중 3명의 폐결핵 환자를 제외한 24명의 환자 중 5명(21%)에서 기관지내시경 검사를 통해서 NTM 폐질환을 진단할 수 있었다. 시술 후 발열이 25명(52%), 기흉이 1명(2%)에서 발생하였다. 결 론 : 흉부 전산화단층촬영에서 기관지확장증과 동반된 다발성 결절이 관찰되면서 객담에서 NTM이 여러 차례 분리되는 환자에서 기관지내시경술은 NTM의 폐조직침범을 확인하는데 도움이 될 수 있으며, NTM 폐질환이 의심되지만 객담검사만으로 NTM 폐질환 진단기준을 만족하지 못하는 환자에서 기관지내시경술은 NTM 폐질환의 진단에 도움이 될 수 있을 것으로 사료된다.

• 대한의용생체공학회:의공학회지
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• 제31권3호
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• pp.199-209
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• 2010

The locking compression plates-distal femur(LCP-DF) are being widely used for surgical management of the extra-articular complex fractures of the distal femur. They feature locking mechanism between the screws and the screw holes of the plate to provide stronger fixation force with less number of screws than conventional compression bone plate. However, their biomechanical efficacies are not fully understood, especially regarding the number of the screws inserted and their optimal configurations. In this study, we investigated effects of various screw configurations in the shaft and the condylar regions of the femur in relation to structural stability of LCP-DF system. For this purpose, a baseline 3-D finite element (FE) model of the femur was constructed from CT-scan images of a normal healthy male and was validated. The extra-articular complex fracture of the distal femur was made with a 4-cm defect. Surgical reduction with LCP-DF and bone screws were added laterally. To simulate various cases of post-op screw configurations, screws were inserted in the shaft (3~5 screws) and the condylar (4~6 screws) regions. Particular attention was paid at the shaft region where screws were inserted either in clustered or evenly-spaced fashion. Tied-contact conditions were assigned at the bone screws-plate whereas general contact condition was assumed at the interfaces between LCP-DF and bone screws. Axial compressive load of 1,610N(2.3 BW) was applied on the femoral head to reflect joint reaction force. An average of 5% increase in stiffness was found with increase in screw numbers (from 4 to 6) in the condylar region, as compared to negligible increase (less than 1%) at the shaft regardless of the number of screws inserted or its distribution, whether clustered or evenly-spaced. At the condylar region, screw insertion at the holes near the fracture interface and posterior locations contributed greater increase in stiffness (9~13%) than any other locations. Our results suggested that the screw insertion at the condylar region can be more effective than at the shaft during surgical treatment of fracture of the distal femur with LCP-DF. In addition, screw insertion at the holes close to the fracture interface should be accompanied to ensure better fracture healing.