• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.325-328
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• 2001

정상적인 뉴런의 활성전위는 외부에서 일정한 자극이 인가되었을 때 세포막을 기준으로 하여 각 이온간의 농도 차에 의해 발생한다. 최근에 관심이 되어지고 있는 쇼크에 의한 세포가 손상이 발생할 경우, 즉 신호를 받아들이고 전달하는 뉴런 중에서 축색에 이온채널이 이상증세를 발생하면 신경 전달 흐름을 흐트러지게 하여 이웃한 정상세포에게 커다란 영향을 미치게 된다. 이것은 병리학적인 중요한 역할을 하는 축색 내에 이상이 발생하였다고 가정을 하지만 이 가정을 뒷받침 해 주는 증거는 매우 적다고 보고되고 있다. 최근 연구에서 손상된 축색의 모델은 쇼크이후에 이온의 칼륨 채널에 blocking 현상이 발생하여 나트륨 이온이 다수 유입됨을 고려하고있다. 이에 본 연구에서는 쇼크나 충격에 의해 축색의 손상을 입을 경우 운동신경의 변형으로부터 병리학적인 중요한 이상결과를 일으킬 수 있는 상태를 고려하여 신경모델을 설계해 시뮬레이션 해 보았다.

• Journal of Veterinary Clinics
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• v.15 no.2
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• pp.378-385
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• 1998

Chloramphenicol주사에 의한 좌골신경손상을 유발한 후 Prednisolone을 이용한 약물처치군, 전침군 및 전침과 약물을 병용한 군에서 각각 회복속도를 비교하였다. 정상보행 횟수, pinching을 통한 감각신경의 통감반응,그리고 병리조직소견 등을 죠사한 결과를 요약 하면 다음과 같다. Enrofloxacin, cefazolin, cephalexin, penicillin 등의 좌골신경주위 주사게 서는 신경마비가 관찰되지 않았으나 chloramphenicol을 주사할 경우에는 좌골신경손상으로 인한 편측성 후지마비가 유발되어 knuckling 반응을 보였다. Chloramphenicol을 투여한후 좌골신경손상에 대한 각 처치에서 정상보행 횟수는 8-12주까지는 침술처치군이 약간 중가하 였으나, 처리군간 유의성은 관찰되지 않았다. 실험기간동안 chloramphenicol 에 의한 신경손 상에 대한 각 처치군별 병리조직 소견은 호전양상이 관찰되지 아니하였다.

• Journal of Chest Surgery
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• v.41 no.1
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• pp.128-132
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• 2008

Penetrating vascular trauma to zone one of the neck is potentially life-threatening. Trauma in this anatomical location is difficult to access and manage because the neck is a small anatomic area with the anatomical proximity of vital structures. An accurate diagnosis and aggressive surgical intervention are critical to the successful outcome of penetrating zone one vascular trauma in the neck. Here we report two cases with review of the medical literature.

• Journal of Veterinary Clinics
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• v.26 no.5
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• pp.441-444
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• 2009

Ischemia-reperfusion (I/R) injury is associated with an increased risk of acute rejection, delayed graft function and long-term changes after kidney transplantation. The reperfusion models remain unsolved complications such as vascular obstruction and blood leakage. We developed an alternative model of isolated hemoperfusion in porcine kidneys. In the present study we introduced a newly developed reperfusion method. A connector was used instead of surgical suture for the vascular anastomosis on the inguinal region in which main femoral vessels are parallel and big enough to perfuse the kidney. To assess renal perfusion quality of the modified hemoreperfusion model, we analyzed both hemodynamic values and patterns of I/R injury following a renal reperfusion. Following unilateral nephrectomy, the kidneys were preserved for 0, 24 and 48 hours at $4^{\circ}C$ with histidine-tryptophan ketogluatarate (HTK) solution and reperfused for 3 hours by vascular anastomosis connected to the femoral artery and vein in inguinal region. Histolopathological examinations were assessed on kidney biopsy specimens, taken after each cold storage and reperfusion. No differences of hemodynamic values were observed between aorta and femoral artery. The average warm ischemia time before reperfusion start was $7.0{\pm}1.1$ minutes. There were no complications including vascular obstruction and blood leakage during the reperfusion. I/R injury of the perfused kidneys in this model was dependent upon the cold ischemia time. The results support that the modified perfusion model is simple and appropriate for the study of early renal I/R injury and transplant immunology.

• Journal of the Korean Arthroscopy Society
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• v.16 no.1
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• pp.17-25
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• 2012

Purpose: The aim of this retrospective study was to evaluate the relationship between appearance and size of bone bruise and severity of anterior cruciate ligament (ACL) injury with magnetic resonance imaging (MRI), furthermore, to identify the mechanism of ACL injury by analyzing the footprint of bone bruise. Materials and Methods: Sixty-five subjects who was taken an MRI within 6 weeks after acute ACL injury were studied. All MRI showed ACL injury and associated bone bruises. Bone bruises were analyzed using Costa-Paz classification based on appearance and location and also scored using Kornaat bone bruise grading system based on size and location. The severity of the ACL injury was graded using a 4-point system (ie, grade 0-3) with oblique coronal MRI. Results: There was statistically significant correlation between Costa-Paz classification of bone bruises in lateral femoral condyle and grade of ACL injury. There were more type 2 lesions in partial tear group (grade 1, 2), however, type 3 lesions of Costa-Paz classification in complete tear group (P=0.037). Significant positive correlations were observed between Kornaat total bone bruise score and grade of ACL injury (P=0.014). Most common ACL injury mechanism was pivot shift injury. Other mechanisms were clip valgus injury, phantom foot injury, and hyperextension injury. Conclusion: It is highly suggested that appearance and size of bone bruise is related to severity of ACL injury after acute ACL injury. The foot print of bone bruise provides valuable clues to identify ACL injury mechanism.

• Magazine of the Korea Concrete Institute
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• v.7 no.5
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• pp.172-178
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• 1995

Concrete contains numerous microcracks at initially poured. The growth and propagation of nicrockacsk are believed tc finally incur the faiure of concrete. These processings are understood as a damage. Damage IS represented as a second-order tensor and crack is treated as a con tinuum phenomenon. In this paper, damage is characterized through the effective stress concept together with the hypothesis of elastic energy equivalence, and damage evolution law and constitutive equation of a damage model are derived by using the Helmholtz frte eriergy and the dissipation potential by means of the thermodynamic principles. The constitutive equation of the model includes the effects of elasticity, anisotropic damage and plasticity of concrete. There are two effective tangent stiffness tensors in this model : one is for elastic-darnage and the other for plastic damage. For the verification of the model, finite element analysis was performed for the analysis of concrete subjec:t to uniaxial and biaxial loading and the results obtained were compared with test results.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.8
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• pp.780-788
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• 2009

AE technique was applied to the static structural test of the composite wing structure to evaluate the structural integrity and damage. During the test, strain and displacements measurement technique were used to figure out for static structural strength. AE parameter analysis and source location technique were used to evaluate the internal damage and find out damage source location. Design limit load test, the 1st and 2nd design ultimate load tests and fracture test were performed. Main AE source was detected by an sensor attached on skin near by front lug. Especially, at the 1st design ultimate test, strain and displacements results didn't show internal damage but AE signal presented a phenomenon that the internal damage was formed. At the fracture test, AE activities were very lively, and strain and displacements results showed a tendency that the load path was changed by severe damage. The internal damage initiation load and location were accurately evaluated during the static structural test using AE technique. It is certified from this paper that AE technique is useful technique for evaluation of internal damage at static structural strength test.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.4
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• pp.349-355
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• 2003

Material degradation due to corrosion fatigue was evaluated nondestructively using backward radiated Rayleigh surface wave. h corrosion fatigue test was carried out for the specimens made of thermo-mechanically controlled process steel in 3.5wt.% NaCl solution at $25^{\circ}C$. The backward radiation profile, which is the amplitude variation of backward radiated ultrasound according to the incident angle, of the specimens were measured in water at room temperature after the corrosion fatigue test. The velocity of Rayleigh surface wave, determined from the incident angle at which the profile of the backward radiated ultrasound became maximum, decreased for the specimen that had the large number of cycles to failure in the corrosion fatigue test. This fact implies that the corrosion degradation occurred at specimen surface in this specific test is dominantly dependant on the me exposed to corrosion environment. The result observed in the present work demonstrates the high potential of backward radiated Rayleigh surface wave as a tool for nondestructive evaluation of corrosion degradation of aged materials.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.1
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• pp.10-17
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• 2000

In boiler high-temperature pipelines such as main steam pipe, header and steam drum in fossil power plants, conventional measurement techniques(replica method, electric resistance method, and hardness test method) for measuring creep damage have such disadvantages as complex preparation and measurement procedures, too many control parameters. And also, these techniques have low practicality and applied only to component surfaces with good accessibility. It needs to apply a reliable and quantitative ultrasonic nondestructive evaluation method that can be replaced for these equipment. In this study, both artificial creep degradation test using life prediction formula and frequency analysis by ultrasonic tests for crept specimens were carried out for the purpose of nondestructive evaluation for creep damage. As a result of ultrasonic tests for crept specimens, we conformed that the high frequency side spectra decrease and central frequency components shift to low frequency band, and also their bandwidth decreases as increasing creep damage in backwall echos.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2668-2676
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• 2011

In order to analyze the variation in length of stay(LOS) of injury inpatients, we developed severity-adjusted LOS model using Korean National Discharge In-depth Injury Survey data of Center for Disease Control. Appling this model, we calculated predicted values and, after standardizing LOS using the differences from the actual values, analyzed the variation in LOS. Major factors affecting severity-adjusted LOS of injury inpatients were found to be severity, surgery(or no surgery), age, injury mechanism and channel of hospitalization. Result of analysis of the differences between the actual values and predicted values adjusted by decision tree model suggested that there were statistically significant differences by hospital size(number of beds), type of insurance and location of institution. In order to reduce the variation in LOS, efforts should be exerted in developing nationwide treatment protocol, inducing medical institutions to utilize it, and furthermore systematically evaluating it to reduce the variation continually.