• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2001년도 춘계학술발표대회
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• pp.47-47
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• 2001

The neuropeptide vasopressin (VP) is a nine- amino acid hormone synthesized as preprohormone in the cell bodies of hypothalamic magnocellular neurons. The tumor in magnocellular neurons of the hypothalamus is associated with disfunctions of the cell bodies, leading to the diabetes insipidus. In order to study with the diabetes insipidus caused by a defect in VP synthesis and its secretion, we have produced the transgenic mice regulated by vasopressin promoter inserted to SV40 T antigen coding sequence (pVPSV.IGR2.1). One transgenic line expressing high levels of SV40 T antigen was propagated. The founder and all transgene positive adult animals have appeared with shorten mortality or apparent phenotypic abnormalities, including immune complex disease, and eventually die between 4 and 8 months of age. The mRNA and protein of SV40T antigen transgene were detected in brain of fetus as well as in brain, spleen, lung and lymph node in moribund at the age of 20 weeks. Histological analysis of transgenic mice showed that tumor developed in brain similar to primitive neuroectodermal tumors (PNET) in man. We also detected lymphomas in spleen and lymph node, and consequent tumor formation in various tissues of the transgenic mice. In pVPSV.IGR2.1, 21% mice showed brain tumor (PNET) at 5 weeks and 100% mice showed brain tumor after 15 weeks. In addition, Expression of apoptosis related genes (Bcl-28 & Bax) was increased over their age in mice with PNET as compared to control mice. Apoptosis related gene expression might be deregulated in mice with brain tumor. However, transgenic mice were not developed with the diabetes insipidus. These mice represent the first disease model to exhibit primitive neuroectodermal tumor in brain, as well as a unique model system for exploring the cellular pathogenesis of lymphomas.

• Journal of Korean Neurosurgical Society
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• 제58권5호
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• pp.454-461
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• 2015

Objective : In this study, we aimed to investigate the underlying ethiological factors in chiari malformation (CM) type-I (CMI) via performing volumetric and morphometric length-angle measurements. Methods : A total of 66 individuals [33 patients (20-65 years) with CMI and 33 control subjects] were included in this study. In sagittal MR images, tonsillar herniation length and concurrent anomalies were evaluated. Supratentorial, infratentorial, and total intracranial volumes were measured using Cavalieri method. Various cranial distances and angles were used to evaluate the platybasia and posterior cranial fossa (PCF) development. Results : Tonsillar herniation length was measured $9.09{\pm}3.39mm$ below foramen magnum in CM group. Tonsillar herniation/concurrent syringomyelia, concavity/defect of clivus, herniation of bulbus and fourth ventricle, basilar invagination and craniovertebral junction abnormality rates were 30.3, 27, 18, 2, 3, and 3 percent, respectively. Absence of cisterna magna was encountered in 87.9% of the patients. Total, IT and ST volumes and distance between Chamberlain line and tip of dens axis, Klaus index, clivus length, distance between internal occipital protuberance and opisthion were significantly decreased in patient group. Also in patient group, it was found that Welcher basal angle/Boogard angle increased and tentorial slope angle decreased. Conclusion : Mean cranial volume and length-angle measurement values significantly decreased and there was a congenital abnormality association in nearly 81.5 percent of the CM cases. As a result, it was concluded that CM ethiology can be attributed to multifactorial causes. Moreover, congenital defects can also give rise to this condition.

• 대한소아치과학회지
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• 제31권1호
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• pp.120-125
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• 2004

Cornelia de Lange Syndrome은 이형성적 특징들에 의해 특징 지워지는 증후군으로서 정확히 알려지지 않은 원인을 가진 이상증이다. 이 증후군은 이형성적 임상증상에 의거하여 진단되기 때문에 염색체 검사, 유전자 검사 등의 진단 목적의 다른 검사들은 유효하지 않다고 할 수 있다. 임상증상으로는 전반적 발육 장애 정신지체, 외소증 다모증(hypertrichosis), 갈매기 모양의 눈썹(confluent eye brows), 낮은 헤어라인, 낮고 평평한 코, 위로 들린 코끝, 사지 기형, 발가락의 합지증(webbing), 심장기형, 위식도 역류 질환, 청력 이상, 그리고 안 질환 등이 나타나며 구강관련 증상으로는 왜소악 치아 맹출 지연, 구순 구개열, 높은 구개궁, 얇은 상순, 그리고 처진 구각 등이 나타난다. 본 증례에서는 전북대학교병원 소아치과에 치아 우식증을 주소로 내원한 Cornelia do Lange Syndrome을 가진 3세 및 4세 여환의 치료 예를 보고하는 바이다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.150-150
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• 2008

본 연구에서는 Wet chemistry damage가 Nanopatterned p-ohmic electrode에 미치는 영향을 연구하였다. Nanopattern은 Metal clustering을 이용하여, P-GaN와 Ohmic형성에 유리한 Pd을 50$\AA$ 적층한 후 Rapid Thermal Annealing방법으로 $850^{\circ}C$, $N_2$분위기에서 3min열처리를 하여 Pd Clustering mask 를 제작하였다. Wet etching은 $85^{\circ}C$, $H_3PO_4$조건에서 시간에 따라 Sample을 Dipping하는 방법으로 시행하였다 Ohmic test를 위해서 Circular - Transmission line Model 방법을 이용하였으며, Atomic Force Microscopy과 Parameter Analyzer로 Nanopatterned GaN surface위에 형성된 Ni/ Au Contact에서의 전기적 분석과, 표면구조분석을 시행하였다. AFM결과 Wet처리시간에 따라서 Etching형상 및 Etch rate이 영향을 받는 것이 확인되었고, Ohmic test에서 Wet chemistry처리에 의한 Tunneling parameter와 Schottky Barrier Height가 크게 증/감함을 관찰하였다. 이러한 결과들은 Wet처리에 의해서 발생된 Defect가 GaN의 표면과 하부에서 발생되며, Deep acceptor trap 및 transfer거동과 밀접한 관련이 있음을 확인 할 수 있었다. 보다 자세한 Transport 및 Wet chemical처리영향에 관한 형성 Mechanism은 후에 I-V-T, I-V, C-V, AFM결과 들을 활용하여 발표할 예정이다.

• 대한전자공학회논문지TC
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• 제38권12호
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• pp.39-48
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• 2001

본 논문에서는 마이크로스트립 라인에 포토닉 밴드갭(photonic bandgap: PBG) 구조를 구현할 경우 저지대역 내에 형성되는 통과대역의 부분대역폭(fractional bandwidth)을 효과적으로 조절할 수 있는 PBG 구조의 설계에 관하여 연구하였다. 이 구조는 결함을 갖는 통상적 PSG 구조의 기본 PSG 셀(cell)에 스텁(stub)을 더하여 구현한 것으로 PBG 셀에 첨가된 스텁 길이가 증가함에 따라 스컷(skirt) 특성이 현저하게 개선됨을 볼 수 있었다. 이때 차단주파수(cutoff- frequency), 저지대역 및 통과대역의 중심주피수는 저주파 쪽으로 이동하였고 통과대역폭은 감소하였다. 이러한 결과는 PBG 셀에 스텁을 활용함으로써 저지대역 내에 형성되는 통과대역의 부분대역폭을 효과적으로 조절할 수 있음을 보여준다. 또한 스텁을 갖는 PBG 구조를 응용하여 우수한 스컷 특성을 갖는 듀플렉서를 설계할 수 있음도 보였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.623-628
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• 2007

도시 대중교통을 주도하는 도시철도에서의 중요한 기능인 신호 연동장치의 주요 논리 회로 중 가장 취약한 3, 4호선의 소형 (Non-Vital) 계전기를 성능이 향상된 전자연동장치(PLC)로 개량함으로서 사전 장애 발생요인을 제거, 열차 안전운행 확보는 물론 설비의 현대화로 업무 향상에 기여하고 신호설비 유지 보수의 합리화 및 효율화를 기할 수 있도록 신호설비의 기능개선 및 발전 방안이 되도록 하였다. 특히 고장 발생 빈도를 낮추기 위한 방안과 설비 보완 및 신설 등 종합적이고 실현 가능한 설비를 구현하고자 하였으며, 기존의 노후된 신호시설이나 교체 예정인 신호 설비들을 효율적으로 개량하기 위한 방안으로 신호 관련기술기준과 표준을 바탕으로 신호시스템의 합리적 발전에 일익을 담당코자 하였다.

• Archives of Plastic Surgery
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• 제39권5호
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• pp.463-468
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• 2012

Background In the extremities of premature infants, the skin and subcutaneous tissue are very pliable due to immaturity and have a greater degree of skin laxity and mobility. Thus, we can expect wounds to heal rapidly by wound contraction. This study investigates wound healing of full-thickness defects in premature infant extremities. Methods The study consisted of 13 premature infants who had a total of 14 cases of full-thickness skin defects of the extremities due to extravasation after total parenteral nutrition. The wound was managed with intensive moist dressings with antibiotic and anti-inflammatory agents. After wound closure, moisturization and mild compression were performed. Results Most of the full-thickness defects in the premature infants were closed by wound contraction without granulation tissue formation on the wound bed. The defects resulted in 3 pinpoint scars, 9 linear scars, and 2 round hypertrophic scars. The wounds with less granulation tissue were healed by contraction and resulted in linear scars parallel to the relaxed skin tension line. The wounds with more granulation tissue resulted in round scars. There was mild contracture without functional abnormality in 3 cases with a defect over two thirds of the longitudinal length of the dorsum of the hand or foot. The patients' parents were satisfied with the outcomes in 12 of 14 cases. Conclusions Full-thickness skin defects in premature infants typically heal by wound contraction with minimal granulation tissue and scar formation probably due to excellent skin mobility.

• Archives of Plastic Surgery
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• 제43권5호
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• pp.418-423
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• 2016

Background Skin grafting is a relatively simple and thus widely used procedure. However, the elastic and structural quality of grafted skin is poor. Recently, various dermal substitutes have been developed to overcome this disadvantage of split-thickness skin grafts. The present study aims to determine the feasibility of RapiGraft as a new dermal substitute. Methods This prospective study included 20 patients with partial- or full-thickness skin defects; the patients were enrolled between January 2013 and March 2014. After skin defect debridement, the wound was divided into two parts by an imaginary line. Split-thickness skin grafting alone was performed on one side (group A), and RapiGraft and split-thickness skin grafting were used on the other side (group B). All patients were evaluated using photographs and self-questionnaires. The Manchester scar scale (MSS), a chromameter, and a durometer were used for the scar evaluation. The average follow-up period was 6 months. Results The skin graft take rates were 93% in group A and 89% in group B, a non-significant difference (P=0.082). Statistically, group B had significantly lower MSS, vascularity, and pigmentation results than group A (P<0.05 for all). However, the groups did not differ significantly in pliability (P=0.155). Conclusions The present study indicates that a simultaneous application of RapiGraft and a split-thickness skin graft is safe and yields improved results. Therefore, we conclude that the use of RapiGraft along with skin grafting will be beneficial for patients requiring reconstructive surgery.

• 비파괴검사학회지
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• 제28권1호
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• pp.46-53
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• 2008

복합재료의 내부 결함 평가를 위해 일반적으로 적용되어온 초음파 C-스캔 기법은 섬유자동 배열을 통한 정밀 성형 공정에 적용하기에는 많은 어려움이 있다. 따라서 본 연구는 복합재료의 정밀 성형 공정 중에 발생되는 각종 내부 결함들을 비파괴적, 비접촉으로 평가하기 위한 새로운 하이브리드 초음파 평가 기법을 확립하는데 목적이 있다. 이를 위하여 본 연구에서는 초음파 산란 반사(scattering reflection) 방식을 토대로 한 새로운 이중 피치-캐치(dual pitch-catch) 기법을 확립하여 기존의 결함평가를 위해 시험편의 스캔에 소요되는 시간을 줄이면서 우수한 결함 영상을 얻을 수 있는 새로운 하이브리드 기법을 개발하였다. 즉 두 가지 종류의 열경화성 및 열가소성 복합재료(carbon/epoxy, carbon/PPS) 적층판의 내부 박리(delamination) 결함의 영상화를 위하여 레이저를 이용한 유도 초음파의 발생 및 이중 피치-캐치(pitch-catch)방식을 토대로 한 비접촉식 공기 정합 트랜스듀서(air-coupled transducer)를 이용하여 결함 영상을 얻기 위한 핵심 알고리즘을 확립하였다.

• Tribology and Lubricants
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• 제31권3호
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• pp.109-124
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• 2015

This paper presents a wear analysis procedure for the journal bearings on a stripped-down single-cylinder engine during start-up and coast-down by motoring. A journal bearing is in the mixed elastohydrodynamic (EHL) lubrication region when the shaft speed is less than the corresponding lift-off speed. Below the lift-off speed, a wear scar can form on bearing surfaces. In part 1 of this paper, we develop the appropriate formulations and the calculation procedure for the analysis. Specifically, we formulate an equation for modified film thickness in a journal bearing considering the additional wear volume. In order to obtain the modified specific wear rate induced by the modified Archard’s wear coefficient, we utilized the extended non-dimensional diagram for the specific wear rate, k, the fractional film defect coefficient, Ψ and the asperity load sharing factor, γ₂. This asperity load sharing factor is newly calculated by setting the Zhao-Maietta-Chang (ZMC) asperity contact pressure equation coupled with the central film thickness equation derived by using the ZMC asperity contact model equal to the modified central contact pressure derived by using the central (or maximum) contact pressure at the dry rough line-contact configuration. We can use the procedure introduced in this paper to determine the lifetime (or longterm) linear wear in radial journal bearings that is a result of repeated stop-start cycles.