• Journal of radiological science and technology
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• v.34 no.2
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• pp.97-103
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• 2011

The Full-length examination of the femur sometimes does not show all of the femur because of the limited width in collimator and size of detectors although it is located in the diagonal direction. Aim of this study is to identify usefulness of the method of combining images which obtained from two radiographic images containing the femoral head and condyle respectively. Our group interviewed 30 radiological technologists who used both palliative DR method and SM method in their examinations of the femur of patients who were carried to the emergency rooms in Gwang-ju city from August 2007 to November 2009. We evaluated twenty images according to the contraction of femoral neck, turning of knee joints and inclusion of the femur. The examination were performed by two radiologists and six radiological technologists who have more than ten years of career. The results are as follows: SM method was graded with higher score for examination time, number of examiners, emaciation, retake and patients' discomfort (p< 0.001) while the. SM method was scored higher than the palliative DR method in the palliative DR method for examination of long bone.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.1
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• pp.47-57
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• 2010

An undisturbed healing process without micromotion at the implant-bone interface is essential for achievement of osseointegration of dental implant. Therefore, initial stability was advocated as prerequisite for successful clinical outcome. Adequate bone quality and quantity were important to achieve initial stability and to prevent early failures. However there were few published data available regarding the effect of design change in implant geometry on initial stability of the implants. The purpose of the current study was to assess the initial stability of various designs of implants when placed into artificial bone materials of varying qualities and shapes of insertion holes. Within the scope of this study, the following results were drawn. Bone quality was major importance to achieve initial stability. Initial stability was higher on GS II which had additional design feature of double thread. With a tapered design of implant such as GS III showed a higher initial stability than straight one. An insertion hole with the similar shape of implant would lead to reduce a compression force on cortical bone and enhance a bone anchorage on cancellous bone.

• The Journal of the Korean dental association
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• v.48 no.2
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• pp.96-105
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• 2010

Titanium implant is used as the most popular dental material for replacement of missing teeth recently. A lot of studies on the surface modification of titanium implant have been carried out for enhancing osseointegration. The surface modification techniques could be classified as follows; topographic modifications which provide roughness and porosity, chemical surface modificationss or deposition of osseoconductive materials, and biochemical modifications to immobilize bone growth factors on titanium surface. In this study, the current and ongoing surface modification techniques and its typical characteristics used in clinics were reviewed. In the future, study and implication about biochemical modifications including patient' s individual characteristics will be important.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06b
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• pp.283-288
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• 2010

본 논문은 VTK를 이용한 3차원 무릎 MRI 가시화에 대한 프로그램 기술을 제안한다. 기존의 많은 연구에서는 VTK를 사용하여 의료영상에 대한 3차원 가시화 프로그램을 제안하였으나 골관절염 진단을 목표로 한 무릎 3차원 가시화 방법은 아직 많이 제안되지 않고 있다. 본 논문에서는 볼륨렌더링(Volume redering) 기술과 다각형렌더링(Polygonal rendering)기술을 융합하여 무릎 및 연골을 효과적으로 가시화 할 수 있는 방법을 제안한다. 프로그램은 사용자 상호작용이 가능하고 VTK를 이용한 GPU기반의 프로세싱을 기반으로 하기 때문에 실시간 렌더링이 가능하다. 실험결과로부터 제안한 3차원 가시화 기술은 연골과 무릎의 관계를 직관적으로 표현할 수 있어 골관절염 조기진단에 유용하게 사용될 것으로 기대한다.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.4
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• pp.323-329
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• 2018

Traditional options for posterior edentulous treatment include removable partial dentures and implant fixed prostheses. Recently, the concept of implant assisted removable partial denture, in which two treatments are fused, has been introduced in consideration of systemic health and patient's needs, costs, residual alveolar bone status and so on. Implant assisted removable partial denture has the advantage of increasing the retention and stability of the denture and improving its esthetics in cases of large bone defects or biomechanical disadvantages. In addition, it is possible to strategically place the implants in a site where the alveolar bone is relatively sufficient, thereby overcome the limit of the conventional removable partial denture design as well as reducing the burden on a wide range of implant surgery. Cost reduction is also expected. In this case, the patient was treated by placing the implant in both premolar sites of the mandible and fabricating the distal extension removable partial denture with the implant fixed prosthesis as an abutment. After delivering the definitive prosthesis, the patient showed satisfaction with the masticatory function and esthetics. and has been regularly followed-up for more than one year. The following 20-months follow-up case report describes the design of an implant-assisted-removable partial denture (IARPD) in which two cementretained implant crowns used to provide support and stability.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.295-295
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• 2010

생체 식립형 임플란트의 경우 성공도는 매식체의 골유착 정도에 크게 영향을 받는다. 골유착 시 임플란트의 표면 형상과 하중, 골질의 양 등 많은 요인에 영향을 받게 되므로, 임플란트의 안정성을 주기적으로 점검해야할 필요가 있다. 따라서 임플란트 안정성을 공진 주파수 분석법을 이용하여 측정하기 위해 압전소자 제작과 트랜스듀서의 구조를 설계하였다. 유한요소 해석을 통하여 압전소자와 트랜스듀서의 두께와 크기 변화를 통해 측정 주파수 범위를 10kHz대역으로 맞추었으며, 해석 결과를 토대로 샘플제작과 평가를 실시하였다. 평가 결과 시뮬레이션 해석결과와 유사한 10kHz의 주파수 대역을 가지는 것을 볼 수 있었고, 식립된 나사의 고정도가 증가할수록 주파수가 점차 증가하는 결과를 얻을 수 있었다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.49.1-49.1
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• 2009

최근 손상된 생체조직의 재생 또는 대체를 위하여 다공성의 지지체(scaffold)를 이용하는 연구가 활발히 이루어져 왔다. 지지체 재료는 조직 재생을 목적으로 하는 경우에는 생분해성 고분자, 생흡수성 세라믹스 또는 이들의 복합재료가 사용되고, 조직 대체를 목적으로 하는 경우에는 금속 또는 세라믹스 재료가 단독으로 사용된다. 현재 경조직 대체를 위한 임플란트 재료로 사용되고 있는 금속재료 중 대부분이 타이타늄 또는 타이타늄 합금이다. 타이타늄은 비강도, 내식성이 우수하며, 생체 내 환경에서 부동태피막 재생 속도가 빠르고, 섬유상 결체조직 형성 두께가 얇아 생체의료용 소재로서 각광을 받고 있다. 다공성 타이타늄은 기존 타이타늄 소재의 장점에 다공체의 구조적인 특성을 부가하여 하중을 받는 골 결손부에 사용될 경우 뼈와의 탄성계수 차이에서 기인하는 응력차폐(stress shielding) 효과를 최소화할 수 있고, 다공체 내부로 골조직 성장을 유도할 수 있어 지지체와 골조직이 일체화되는 골융합 효과의 극대화를 기대할 수 있다. 본 연구에서는 기공 구조를 다양하게 제어할 수 있고, 3차원적 연결 기공구조를 만들 수 있는 적층조형(layer manufacturing) 기술을 이용하여 3차원 다공성 타이타늄 지지체를 제조하였으며, 이에 대한 세포독성, 조골세포 증식능 등 in vitro 생체적합성을 평가하고, Rat model 을 이용한 in vivo 생체적합성을 평가하였다. 또한 지지체의 골조직 재생 유도성의 증대를 위한 생체활성처리 영향도 분석 평가하였다.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.2
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• pp.158-165
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• 2010

Purpose: The objective of the present study was to histologically evaluate durability and bone regeneration capacity of new synthetic membranes in comparison to clinically available collagen membrane. Material and methods: To the skulls of 12 rabbits, we created 4 bone defects of 6 mm in diameter on each of them. Each of defects were covered with at least one of 5 membranes; No membrane, Collagen ($Ossix^{TM}$), PLGA, HA-coated-PLGA and HA-PLGA/PLGA. After 4, 8, 12 weeks, we cut the skulls and dyed with H-E. And then, the histologic observation was done. Results: In current study, the control group which did not use the membrane showed bone regeneration at 12 weeks and covered the bone defect partially. New bones were formed through the underneath of endocranium, and the upper defect was filled with connective tissues and fats. Collagen membrane ($Ossix^{TM}$) showed new bones after 4 weeks, and they were formed through the membrane which maintained until 12 weeks. PLGA, HA-coated-PLGA, HA-PLGA/PLGA showed bone regeneration after 4 weeks and after 8 weeks, they mostly filled defects. At 12 weeks, we could find new bones and previous bones almost look alike and also, they united well. Membranes were unnoticeable after 4 weeks and were absorbed. Conclusion: Bone formation and maturation of PLGA, HA-coated-PLGA and HA-PLGA/PLGA were faster than the control group. They showed no difference on the application of HA and after 4 weeks, they were absorbed.

• The Korean Journal of Zoology
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• v.38 no.3
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• pp.330-339
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• 1995

In Helice tridens tridens, hylaine cells, small granulocytes, and large granulocytes were identified. Features of hyaline cells include a large nucleus in proportion to the cytoiplasm, and weak electron-dense granules of oval shape and vesicles, and endoplasmic reticulum (ER) in the cytoplasm. Small granulocytes have smaller nucleus than that of the hyaline cells, well-developed ER, Golgi complex, and small, round and electron-dense granules in the cytoplasm. Large granulocytes contain large and electron dense granules (ahout 1 $\mu$m) that fused small granules. Hemocytes of Helice tridens tridens differentiated from hyaline cell to large granulocyte granules of hyaline cells have lysosome and make small vesicles from nuclear envelopes. While these vesicles pass through the Golgi complex, they are filled with electron dense matetials, and then fused with the small granules. They eventually matured into large granules. All of hemocytes have the glycogen particles. In the large granulocytes heterogeneouse granules were supposed to occur by disappearance of granules.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.1
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• pp.8-14
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• 2005

The implementation of vision system using CCD camera which measures the earing rate of aluminium CAN is represented in this paper. In order to optimize the input image, the object of the input image is separated and the position of the image is calibrated. In the preprocessing, the definition of image is improved by the histogram equalization, and then the edges of the input image are detected by the Robert mask. The heights of the four ears and angles of the aluminium CAN are measured manually with the digital vernier calipers in industry. It takes 30 seconds to measure manually the height of one direction of the aluminium CAN at least three times. However, when the proposed system in this paper is applied, it takes 0.02 seconds only. In conclusion, the efficiency of the proposed system is higher than that of the system used in the industry.