• Journal of the Korean Orthopaedic Association
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• v.55 no.2
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• pp.127-134
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• 2020

Purpose: The aims of this study were (1) to investigate the relationship between the characteristics of allogenic bone block and the compressive strength of an allogenic bone block measured by biomechanical experiments, and (2) to compare the maximum pressure load of allogenic bone block with the gap pressure measured at the high tibial opening osteotomy. Materials and Methods: Ten patients who provided informed consent for gap pressure measurements during opening wedge high tibial osteotomy (OWHTO) were included. The gap pressures were measured at 1 mm intervals while opening the osteotomy site from 8 mm to 14 mm. Seventeen U-shaped allogenous wedge bone blocks were made from the femur, tibia, and humerus. The height, width, cross-sectional area, and cortex thickness of the bone blocks were measured, along with the maximum compressive load just before breakage. The relationship between these characteristics and the maximum pressure load of the bone blocks was evaluated. The gap pressures measured in OWHTO were compared with the maximum pressure loads of the allogenous wedge bone blocks to evaluate the possibility of inserting allogenous wedge bone blocks into the osteotomy site without a distractor in OWHTO. Results: The OWHTO gap pressure increased with increasing osteotomy site opening. The mean gap pressure, which occurred at a 14-mm opening, was 282±93 N; the maximum pressure was 427 N. The maximum pressure load of the allografts was 13,379±6,469 N (minimum, 5,868; maximum, 29,130 N) and was correlated significantly with the cortical bone thickness (correlation coefficient=0.693, p=0.002) and cross-sectional area (correlation coefficient=0.826, p<0.001). Depending on the sterilization method, the maximum pressure loads for the bone blocks were 13,406±5,928 N for freeze-dried and 13,348±7,449 N for fresh frozen. The maximum compressive load of the allogenous wedge bone blocks was 13.7-times greater than that in OWHTO opened to 14 mm (5,868 N vs. 427 N). Conclusion: The compressive strength of allogenous wedge bone blocks was sufficiently greater than the gap pressure in OWHTO. Therefore, allogenous wedge bone blocks can be inserted safely into the osteotomy site without a distractor.

• Journal of Educational Research in Mathematics
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• v.13 no.4
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• pp.429-446
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• 2003

Gu-il-jip is a mathematical book of Chosun dynasty in the 18c. It consists of nine chapters including more than 473 problems and their solutions. Analyzing the problems and their solutions, we can appreciate the mathematical researches by the professional mathematicians of Chosun. Especially, it is worth noting the followings: - units for measuring and decimal notations - $\pi$, area of circle, volume of sphere - naming the powers - counting rods - excess and deficit: calculation technique for excess-deficit relations among quantities - rectangular arrays: calculation technique for simultaneous linear equations - 'Thien Yuan' notation: method for representing equations - 'Khai Fang': algorithm for numerical solution of quadratic, cubic and higher equations Based on these analyses, some pedagogical applications are proposed.

• Korean Journal of Cleft Lip And Palate
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• v.8 no.1
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• pp.1-9
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• 2005

1. Introduction : 개방형 비성형술은 직접적인 비소주에 대한 접근으로 진단과 기술상의 장점으로 인하여 과거 수년간 의심의 여지 없이 사용되었으며 또한 비익 연골을 쉽게 사용할 수 있어서 대부분의 경우에 사용되어져 왔다. 그러나 비개방형에 비해 개방형 비성형술의 경우 콧구멍과 비첨부의 비대칭 및 비익부의 길어짐 등의 불만을 호소하는 경우가 많았다. 그러나 개방형 비성형술의 경우 아직도 접근의 용이성 및 대칭성으로 많이 사용되고 있다. 2. Material & Methods : 이에 서울대학교 구강악안면외과에서 1999년부터 2001년까지 개방형 성형술을 시행 받은 환자를 대상으로 술후에 비익과 비첨부의 대칭 및 비공의 크기 정도를 평가해보고 개방형 비성형술의 좋은 결과에 대해 논해보고자 하였다. 3. Resulo : 술 후 환자의 만족도는 높은 편이었으나 양측의 대칭 정도에서는 조금씩 차이를 보여 비첨은 대개 이환측으로 변위되어 있었으며 비공의 크기에서도조금씩 차이를 나타내었다. 4. Conclusion : 지금까지는 주로 비순부의 평균치나 성장 방향을 연구하는데 주로 계측치들이 이용되었던 반면, 수술 후 일어날 수 있는 비부의 변화앙상을 나타내는 데에는 부족한 점이 많았고 특히 구순 구개열 환자에서 연령, 성별에 따른 표준자료의 부족으로 형태학적인 비교 연구 및 표준자료가 부족하였다. 따라서 이번 연구에서는 구순 구개열 환자의 술 전 및 술 후 의 변화 양상을 파악하는데 도움이 될 만한 차트를 만들었고 변화양상을 연구하는데 도움이 될만한 자료를 제시하는 바이다.

• 대한관절경학회:학술대회논문집
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• 2009.10a
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• pp.93-98
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• 2009

족관절 고정술은 족관절에 발생한 심한 관절염(end-stage arthritis)에서 전통적으로 시행하던 술식으로 현재 사용되고 있는 인공 족관절 치환술이 발달되기 전까지는 gold standard 로 알려져 있었으며 현재에도 심한 족관절의 변형이나 파괴, 족관절 인공 관절의 실패시에 시행되고 있다. 1897년 Albert가 처음으로 족관절 고정술을 소개한 이후로 30여가지가 넘는 방법이 행해지고 있으나 개방적 관절 고정술의 단점인 수술 후 염증, 유합 지연, 연부조직의 손상에 의한 피부 괴사 등을 극복하고 유합물을 높이기 위해 다양한 내고정 및 외고정 장치를 사용하고 있다. 관절경 술식이 발달하면서 Schnider가 1983년 최초로 관절경을 이용한 족관절 고정술을 발표한 이후로 관절경하의 족관절 고정술은 개방적 족관절 고정술 보다 높은 유합율과 적은 수술 합병증으로 인해 관심의 대상이 되었지만 족관절의 변형이 심한 경우에는 시행하기 어려운 단점이 있는 것으로 알려져 왔다.

• Journal for History of Mathematics
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• v.22 no.4
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• pp.29-40
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• 2009

we know that Zeng Cheng Kai Fang Fa is the generalization of the method of square roots and cube roots of ancient through the investigation of China mathematics. In this paper, we have research on traditional solutions equations of China mathematics and the development solutions of equations used by Chosun mathematicians.

• Journal of Chest Surgery
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• v.40 no.11
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• pp.765-769
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• 2007

Background: The curative treatment of choice for empyema is decortication of the pleura. The risks of this treatment however are increased for the patient with reduced pulmonary function, complicated calcification or septic shock. In the past, open window thoracostomy was a final stage treatment for chronic empyema. Relatively safe treatment of empyema could be achieved in difficult cases with a closure of the open window after open drainage and use of a myocutaneous flap (one stage or staged). Material and Method: A retrospective study of the cause, progression and final outcome of empyema patients who received open window thoracostomy was performed. 21 patients were followed from 1995 to 2004 in the department of Thoracic and Cardiovascular Surgery in the College of Medicine, Pusan National University. Result: The average age of the patients was $57.5{\pm}15.5$ years (range $25{\sim}78$ years), of whom 16 (76.2%) were men and five (23.8%) were women. Pulmonary function test results showed an average FEV1 of $1.58{\pm}0.49 L$. The type of empyema was tuberculous empyema in 13 cases (61.9%), aspergillosis in three cases (14.3%), parapneumonic empyema in three cases (14.3%) and post-resectional empyema in two cases (10%). Bronchopulmonary fistula was seen in 14 cases. Eight cases were complicated by severe calcification of the pleura. For the four cases of bronchopulmonary fistula, the patients' serratus anterior muscle was covered in their first operation. The average number of ribs resected was $4{\pm}1$. Closure of the open window thoracostomy was performed in 12 cases. The average time to closure after open drainage was $10.22{\pm}3.11$ months and the average defect of the empyemal cavity before the final operation was $330{\pm}110 cc$. Among the 12 cases, there were two cases of spontaneous closure. In two cases closure was only achieved by using the reserved skin fold during the first surgery. Of the remaining eight cases, in seven we used the myocutaneous flap (four cases of lattisimus dorsi muscle and three cases of pectoralis major muscle), and in one case we used soft tissue. As regards complications of the closure, tissue necrosis occurred in one case, which led to failed closure, and there was one case of abdominal hernia in the rectus abdominis muscle flap. One patient died within 30 days of the surgery and one patient died of metastatic cancer. Conclusion: A staged operation with a final closure using open window thoracostomy, which consists of open drainage, transposition of the muscle and a myocutaneous flap, can be a safe and effective option for the chronic empyema patient who is difficult to cure with traditional surgical methods.

• Clinics in Shoulder and Elbow
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• v.14 no.2
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• pp.222-228
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• 2011

Purpose: To compare the mid-term clinical results of arthroscopic and open repair for large to massive rotator cuff tear. Materials and Methods: We retrospectively reviewed 48 patients who underwent either arthroscopic or open repair for large to massive rotator cuff tear. 28 patients underwent arthroscopic repair and 20 patients had open repair. The clinical outcome for the 2 groups was evaluated using range of motion, Visual Analogue Scale (VAS) for pain and function, American Shoulder and Elbow Society (ASES) score and Korean Shoulder Scoring System (KSS) score. Results: The range of motion, VAS for pain and function and ASES score was improved significantly in both groups at the final follow-up visit compared with preoperative values. However, there were no significant differences between the two groups statistically (p>0.05). There were no significant differences between the two groups statistically at the final follow-up KSS score (p>0.05) either. Conclusion: We could obtain improved mid-term clinical outcomes in both arthroscopic repair and open repair without any statistically significant differences between the two groups.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2008.03a
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• pp.131-131
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• 2008

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2007.03a
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• pp.101-102
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• 2007

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.30 no.6
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• pp.55-64
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• 2001

전기적 스윗치 기능을 갖는 신기술의 개방검지형 자동스프링클러헤드의 구조, 원리 및 특성과 이를 설치하는 습식 스프링크러시스템의 구성방식 및 그 실효성에 대해 소개한다.