• 대한정형외과스포츠의학회지
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• 제10권1호
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• pp.35-40
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• 2011

목적: 만성 발목 관절 외측 불안정성 환자에 대한 기계적 불안정성의 평가에서 스트레스 방사선검사의 진단적 유용성을 알아보고자 하였다. 대상 및 방법: 본원에서 변형 Brostrom 술식을 시행받은 환자들 중 수술 소견상 외측 측부인대(전 거비 인대)의 완전 파열이 확인되었던 42예를 대상으로 하였다. 대조군으로는 발목 관절 손상의 과거력이 없고 이학적 검사상 불안정성 소견을 보이지 않는 정상 한국인 성인 총 60명(120예)을 모집하였다. Telos 기구를 이용한 전방 전위 및 내반 스트레스 검사를 시행한 뒤, 거골 경사각과 거골 전방전위 정도를 계측하였다. 대조군에서 얻어진 정상범위를 기준으로 스트레스 방사선검사의 민감도, 특이도, 양성 예측도, 음성 예측도를 분석하였다. 결과: 스트레스 방사선검사 상 정상 한국인 성인에서의 거골 경사각은 평균 $4.2{\pm}2.1$도, 거골 전방전위는 평균 $3.9{\pm}1.9$ mm로 계측되었다. 95% 신뢰한계 분석을 이용한 정상 범위의 설정시 거골 경사각의 정상 범위는 8.3도 이하, 거골 전방전위는 7.6 mm 이하로 분석되었다. 이 수치를 기준값으로 하는 경우 발목 관절 스트레스 방사선검사 상 거골 경사각의 민감도는 57%, 특이도는 97%, 양성 예측도는 89%, 음성 예측도는 86% 였고, 거골 전방전위의 민감도는 69%, 특이도는 97%, 양성 예측도는 91%, 음성 예측도는 90% 였다. 결론: 만성 발목 관절 외측 불안정성 환자에 대한 기계적 불안정성의 평가에서 스트레스 방사선검사는 비교적 우수한 특이도 및 양성, 음성 예측도를 보였으나 민감도는 낮아, 유용하지만 정확성은 떨어지는 검사법인 것으로 분석되었다. 기계적 불안정성이 발목 관절 스트레스 방사선검사 상 실제보다 덜 반영된다고 생각되며, 스트레스 방사선검사 소견만으로 발목 관절 외측 불안정성을 배제해서는 안 될 것으로 생각한다.

• Journal of Korean Neurosurgical Society
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• 제48권1호
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• pp.37-45
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• 2010

Objective : Craniovertebral junction (CVJ) consists of the occipital bone that surrounds the foramen magnum, the atlas and the axis vertebrae. The mortality and morbidity is high for irreducible CVJ lesion with cervico-medullary compression. In a clinical retrospective study, the authors reviewed clinical and radiographic results of occipitocervical fusion using a various methods in 32 patients with CVJ instability. Methods : Thirty-two CVJ lesions (18 male and 14 female) were treated in our department for 12 years. Instability resulted from trauma (14 cases), rheumatoid arthritis (8 cases), assimilation of atlas (4 cases), tumor (2 cases), basilar invagination (2 cases) and miscellaneous (2 cases). Thirty-two patients were internally fixed with 7 anterior and posterior decompression with occipitocervical fusion, 15 posterior decompression and occipitocervical fusion with wire-rod, 5 C1-2 transarticular screw fixation, and 5 C1 lateral mass-C2 transpedicular screw. Outcome (mean follow-up period, 38 months) was based on clinical and radiographic review. The clinical outcome was assessed by Japanese Orthopedic Association (JOA) score. Results : Nine neurologically intact patients remained same after surgery. Among 23 patients with cervical myelopathy, clinical improvement was noted in 18 cases (78.3%). One patient died 2 months after the surgery because of pneumonia and sepsis. Fusion was achieved in 27 patients (93%) at last follow-up. No patient developed evidence of new, recurrent, or progressive instability. Conclusion : The authors conclude that early occipitocervical fusion to be recommended in case of reducible CVJ lesion and the appropriate decompression and occipitocervical fusion are recommended in case of irreducible craniovertebral junction lesion.

• 감성과학
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• 제5권4호
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• pp.45-49
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• 2002

가상환경시스템은 매우 현실감 있는 정보를 제공할 수 있다는 점에서 산업, 의료, 교육훈련 등에 널리 사용되고 있다. 그러나 아직 많은 가상환경 시스템에서 부정적 요인으로 멀미, 시각피로, 방향감각 상실로 대표되는 cybersickness중세를 수반하고 있어 그 사용과 확산에 제약이 되고 있다. 이러한 cybersickness문제에 대응하기 위해서는 우선 이것을 객관적으로 측정, 평가할 수 있는 방법의 개발이 필요하다. 이러한 방법들 중의 하나로 신체동요의 정도를 평가 지표로 사용할 수 있다. 이번 연구에서는 45 명의 피실험자들을 대상으로 가상현실 운전시뮬레이터를 운전하기 전과 후의 신체동요 정도를 힘판(force platform)을 이용해 측정하였다. 특히 본 실험에 사용된 가상현실 운전시뮬레이터는 피실험자에게 운동판(motion platform)을 이용해 운동감을 제공할 수 있었고, 피실험자의 멀미 현상이 검지되면, 시야각을 1/3로 줄여주는 멀미 완화 피드백(feedback) 시스템이 연결되어 있었다. 그래서 motion의 제공여부와 feedback의 제공 여부도 실험의 독립변수로 추가하였다. 실험 결과, 가상현실 체험 후 유의한 차이는 아니나 피실험자들의 신체동요가 약간 증가하는 것이 관측되었다. motion과 feedback에 대한 분석에서는, 유일하게 motion을 제공하는 것이 제공 안할 때에 비해 좌우 방향의 신체동요가 더 적어지는 것으로 나타났다. 신체동요를cybersickness의 지표로 사용하기 위해서는 추후연구가 더 요청된다.

• Clinics in Shoulder and Elbow
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• 제5권2호
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• pp.118-123
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• 2002

Purpose: The purpose was to identify the effectiveness of beach-chair position in the arthroscopic Bankart repair over conventional lateral decubitus position with distal traction. Materials & Methods: 36 arthroscopic Bankart repair through July 2000 to July 2001 was done under beach chair position. All cases were shoulder instability. Male patients were 6 and female were 4 with average age of 25 years. Arthroscopic suture anchor was used in 24 cases and average number was 3. Results: Interscalene block was tried in 29 patients and 1 case was changed to general anesthesia. Arthroscopic examination to identify Bankart lesion and associated pathology was done without difficulty Bankart lesions were easily reduced to anatomic position and placed suture anchor and hooking approprately. After the arthroscopic examination,3 cases were converted to open procedure without any positional change. Conclusion: Under interscalene block, the preparation was more simple and the patient could watch arthroscopic procedure with confidence. There was no hindrance in arthroscopic examination and arthroscopic repair could be dont: in more anatomic position. It can be easily changed to open repair if it needed

• International Journal of Fluid Machinery and Systems
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• 제3권3호
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• pp.235-244
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• 2010

Recent studies on the moment whirl due to leakage flow in the back shroud clearance of hydro-turbine runners or centrifugal pump impellers are summarized. First, destabilizing effect of leakage flow is discussed for lateral vibrations using simplified models. Then it is extended to the case of whirling motion of an overhung rotor and the criterion for the instability is obtained. The fluid moment caused by a leakage clearance flow between a rotating disk and a stationary casing was obtained by model tests under whirling and precession motion of the disk. It is shown that the whirl moment always destabilizes the whirl motion of the overhung rotor while the precession moment destabilizes the precession only when the precession speed is less than half the rotor speed. Then vibration analyses considering both whirl and precession are made by using the hydrodynamic moments determined by the model tests. For larger overhung rotors, the whirl moment is more important and cause whirl instability at all rotor speed. On the other hand, for smaller overhung rotors, the precession moment is more important and cancels the destabilizing effect of the whirl moment.

• 대한족부족관절학회지
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• 제8권2호
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• pp.204-207
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• 2004

An unstable second metatarsophalangeal joint may produce pain in the forefoot. Plication of stretched lateral ligament and capsule and transfer of the extensor digitorum brevis under the transverse intermetatarsal ligament performed as the primary procedure to stabilize this painful joint. But the pain was not subsided and the proximal phalanx was resubluxated. So, we osteotomized the second metatarsal to restore a normal alignment of the second toe. Then the symptom was subsided. We report a case of painful instability of the metatarsophalangeal joint of the second toe.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1995년도 추계학술대회논문집; 한국종합전시장, 24 Nov. 1995
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• pp.185-190
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• 1995

In recent years, many researcher have been interested in the stability of a thin beam. Among them, Pai and Nayfeh[1] had investigated the nonplanar motion of the cantilever beam under lateral base excitation and chaotic motion, but this study is associated with internal resonance, i.e. one to one resonance. Also Cusumano[2] had made an experiment on a thin beam, called Elastica, under bending loads. In this experiment, he had shown that there exists out-of-plane motion, involving the bending and the torsional mode. Pak et al.[3] verified the validity of Cusumano's experimental works theoretically and defined the existence of Non-Local Mode(NLM), which is came out due to the instability of torsional mode and the corresponding aspect of motions by using the Normal Modes. Lee[4] studied on a thin beam under bending loads and investigated the routes to chaos by using forcing amplitude as a control parameter. In this paper, we are interested in the motion of a thin beam under torsional loads. Here the form of force based on the natural forcing function is used. Consequently, it is found that small torsional loads result in instability and in case that the forcing amplitude is increasing gradually, the motion appears in the form of dynamic double potential well, finally leads to complex motion. This phenomenon is investigated through the poincare map and time response. We also check that Harmonic Balance Method(H.B.M.) is a suitable tool to calculate the bifurcated modes.

• 한국임상수의학회지
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• 제36권3호
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• pp.166-168
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• 2019

A 22-month-old female mongrel dog weighing 4.8 kg was referred with chief complaint of bite wounds and lameness. The patient showed non-weight bearing lameness on left hindlimb and lateral instability of intertarsal joint. On radiograph, proximal intertarsal luxation between calcaneus and fourth tarsal bone was diagnosed. To imitate the long collateral and calcaneoquartal ligament, bone tunnels were drilled in the distal calcaneus and proximal fifth metatarsal bone. The figure-eight suture was placed with 0.5 mm cerclage wire through the predrilled holes. At 2 weeks after surgery, the lameness of hindlimb was still present. However, the patient had weight bearing lameness for 4 weeks after operation and was able to walk and run without lameness at 5 weeks after surgery. This case report explains the successful correction of intertarsal luxation with a single figure of eight wire suture in case of luxation to the intertarsal joint.

• Journal of Korean Neurosurgical Society
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• 제30권1호
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• pp.114-117
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• 2001

Generally, the posterolateral approach had been recommended in case of extraforaminal disc herniation or lateral stenosis but it has been speculated that this procedure may be feasible to posterolateral disc herniation at the high lumbar levels of the L1-L2 interspace. Topographically, a posterolateral approach should be able to access anteromedial side of the spinal canal without the risk of the bony instability and damage to the neural structures. During the past one year period, three patients with high lumbar discs at the L1-L2 level were treated by the modified posterolateral approach. This article describeds the details of this approach with pertinent literature review.

• Wind and Structures
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• 제23권6호
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• pp.485-503
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• 2016

To investigate the nonlinear aerostatic stability of the Hutong cable-stayed rail-cum-road bridge with ultra-kilometer main span, a FEM bridge model is established. The tri-component wind loads and geometric nonlinearity are taken into consideration and discussed for the influence of nonlinear parameters and factors on bridge resistant capacity of aerostatic instability. The results show that the effect of initial wind attack-angle is significant for the aerostatic stability analysis of the bridge. The geometric nonlinearities of the bridge are of considerable importance in the analysis, especially the effect of cable sag. The instable mechanism of the Hutong Bridge with a steel truss girder is the spatial combination of vertical bending and torsion with large lateral bending displacement. The design wind velocity is much lower than the static instability wind velocity, and the structural aerostatic resistance capacity can meet the requirement.