Measurement of maxillary sinus volume using computed tomography

치의학과/석사[한글] 정상적인 상악동 크기에 관한 표준치는 상악동의 비정상적 상태를 평가하는데 도움을 주고, 상악동이 포함된 외과적 시술인 경우 상악골을 정확하게 수복하고 술후 결과를 평가하는데에도 중요하다. 이에 저자는 20세 이상 한국인 정상 성인 상악동의 횡단 폭경, 전후 폭경 및 고경을 측정하여 체적을 구한 뒤 상악동 각각의 계측치가 상악동 체적과 갖는 상관 관계를 평가하고 성별, 좌우별 상악동 크기의 차이를 알아봄으로써 한국인 정상 성인 상악동 크기의 표준치를 제시하고자 하였다. 1997년 2월부터 1999년 7월까지 연세대학교 치과대학병원 치과방사선과에서 전산화단층사진을 촬영한 20세 이상 성인 환자 중 상악동내에 특별한 증상이나 중격(septa)이 없고, 골절이나 염증, 종양 등의 병변도 없으며, 임상적으로 심한 비대칭 소견이나 악안면부위 수술을 받은 병력이 없는 52명 환자(총 상악동 수 95개동)의 전산화단층사진을 대상으로 후향적으로 고찰, 분석하여 다음과 같은 결과를 얻었다. 1. 전체 상악동 횡단 폭경, 전후 폭경, 고경, 체적의 평균값은 각각 28.33 mm,39.69 mm, 46.60 mm, 21.90 cm** 3이었다. 네 계측 항목 모두 전반적으로 남자가 여자에 비해 다소 큰 경향이 있었으며, 폭경 및 고경에서는 성별간에 통계학적으로 유의성있는 차이가 없었으나, 체적에서는 통계학적으로 유의성있는 차이가 있었다(p<0.05). 2. 좌우별 차이를 보면 상악동 전후 폭경, 고경, 체적에서 통계학적으로 유의성있는 차이가 없었으며, 횡단 폭경에서 통계학적으로 유의성있는 차이가 있었으나(p<0.05), 그 차이의 평균값은 0,84 mm였다. 네 계측 항목 모두 좌우간에 통계학적으로 유의성있는 상관 관계가 있었다(p<0.0001). 3. 상악동의 횡단 폭경, 전후 폭경, 고경은 모두 상악동의 체적과 통계학적으로 유의성있는 상관 관계를 보였다(p<0.0001). 결론적으로 한국인 정상 성인의 상악동은 성별간에는 전반적으로 남자가 여자에 비해 다소 큰 경향이 있었고, 좌우간에는 횡단 폭경을 제외하고 모든 계측치에서 통계학적으로 유의성있는 차이가 없었으며, 네 계측치 모두 좌우간에 유의성있는 상관 관계가 있었다. 따라서 편측으로 상악동의 과성장이나 열성장이 관찰된다면 상악동 크기에 영향을 미칠 수 있는 어떤 상악동 병변이나 발육성 이상을 생각해 볼 수 있을 것으로 사료된다. 또한 상악동 체적과 나머지 세 계측치간에 각각 유의성있는 상관 관계가 있었으므로 상악동 폭경 및 고경이 크면 체적도 클 것으로 예상할 수 있을 것이다. [영문] A standard value for the size of the normal maxillary sinus is important to evaluate the state of the maxillary sinus, as well as to precisely reduce the maxilla and to evaluate the results of an operation involving the maxillary sinus. This study was carried out to propose a standard value for the maxillary sinus volume of a normal Korean adult by measuring the width and height of the sinus and analyzing their correlation with the sinus volume and the difference of the maxillary sinus size respectively between sex, and on the right and left sides. Fifty-two patients(a total of 95 maxillary sinuses) out of adult patients aged 20 years or over who had taken CT in the Department of Dental Radiology, Yonsei University, Dental Hospital, between February 1997 and July 1999 who were without specific symptom, prominent bony septa, fracture, inflammation, tumor, clinical asymmetry and no history of orthognathic surgery were retrospectively analyzed. The results were as follows : 1. The mean transverse width, antero-posterior width, height and volume of the normal Korean adult's maxillary sinuses were 28.33 mm, 39.69 mm, 46.60mm and 21.90 cm**3, respectively. In all four measurements, the mean values in males were larger than in females. There were no significant sex differences in the mean width and height. However, in the mean volume, a significant difference was observed between the sex(p<0.05). 2. In the mean antero-posterior width, height and volume of the maxillary sinus, no significant difference was observed between the right and left side. In the mean transverse width, however, a significant difference was observed(p<0.05), but the mean difference between the two sides was 0.84mm. All four measurements showed a significant correlation between the right and left sides(p<0.0001), 3. The widths and height of the maxillary sinus all showed a significant correlation with the sinus volume(p<0.0001). Conclusively, in the Korean normal adult's maxillary sinus, males tended to be larger than females. Except far the transverse width, all of the measurements showed no significant difference between the right and left side, but significant correlations in the four measurements between both sides were observed. Thus, the overgrowth or undergrowth in the unilateral maxillary sinus may suggest a certain pathosis or developmental abnormalities in the maxillary sinus. Also there were a number of significant correlations between the width, height and volume of the maxillary sinus. So, we can expect that maxillary sinus volume is also large if the width and height are large.ope

광자극발광선량계(OSLD)측정법과 몬테카를로 산출법(MC)에 의한 콘빔시티의 유효선량 평가

치의학전문대학원Objective: The aim of this study was to evaluate the effective dose of three different cone beam computed tomography (CBCT) units with optically stimulated luminescence dosimeters (OSLD). Also, this dosimetric measurement method was compared with Monte Carlo (MC) simulation in Alphard 3030 CBCT unit. Through the measurement process and obtained value, more practical and efficient method in acquiring the effective dose of a CBCT would be suggested. Materials and Methods: Twenty-two optically stimulated luminescence dosimeters (OSLD) were calibrated and equipped in human anthropomorphic phantom of head and neck. The phantom with dosimetry was exposed respectively with C, P and I modes of Alphard 3030 (Asahi Roentgen Ind., Co. Ltd, Kyoto, Japan); Large Jaw and Jaw modes of RAYSCAN α+ (Ray Co. Ltd, Hwaseong-si, Korea); Facial and Dual Jaw modes of CS9300 (Carestream Dental LLC, Atlanta, Georgia). Dose recorded in dosimetry was obtained and organ dose as well as effective dose were obtained in each examination mode of 3 CBCT units. The organ and effective dose were also obtained with MC simulation on three examination modes of Alphard 3030 CBCT unit. For MC simulation, PCXMC software (STUK, Helsinki, Finland) was used and dose-area-product (DAP) value was measured with DAP meter. Results: The effective dose was the highest in C mode, Alphard 3030 and the lowest in Dual jaw mode, CS9300. When comparing the 10 x10 cm FOV mode of all 3 CBCT units, the effective dose was higher in order of Alphard 3030 (258.8 µSv), RAYSCAN α+ (213.8 µSv), and CS9300 (90.7 µSv). The organ dose was the highest in salivary gland and the lowest in bone marrow in the same FOV mode of 3 CBCT units. When compared the result of OSLD in Alphard 3030 with MC simulation, percent difference of the effective dose was 9.8~23.4%. Overall organ dose distribution was consistent in all different examination modes of Alphard 3030 CBCT unit. Conclusion: The effective dose showed tendency of increasing as FOV increased regardless of the CBCT model. In addition, the effective dose varies depending on several other factors such as exposure conditions and geometry of the CBCT, thus the effective dose of various equipment should be examined in the future. Also, MC simulation is expected to be convenient assessment method because it was similar to the OSLD measured value according to the examination modes. 목적: 광자극발광선량계(OSLD)를 이용하여 세 종류의 콘빔시티에서 유효선량을 측정하고, Alphard 3030 콘빔시티에서 OSLD 측정값과 몬테카를로(MC) 시뮬레이션 산출값을 비교하는 것이다. 이를 통해 콘빔시티 유효선량을 획득하기 위한 보다 실용적이고 효율적인 방법을 제안하고자 한다. 재료 및 방법: 초기 보정을 거친 22개의 OSLD를 성인 두경부를 재현한 ATOM (CIRS, Norfolk, VA) 팬텀의 정해진 위치에 각각 삽입하였다. 준비된 팬텀을 세 종류의 콘빔시티를 이용하여 제조사가 제시한 노출조건으로 촬영하였다. Alphard 3030 콘빔시티(Asahi Roentgen Ind., Co. Ltd, Kyoto, Japan)에서 C, P, I 3가지 모드, RAYSCAN α+ 콘빔시티(Ray Co. Ltd, Hwaseong-si, Korea)에서 Large jaw, jaw 2가지 모드, CS9300 콘빔시티(Carestream Dental LLC, Atlanta, Georgia)에서 Facial, Dual jaw 2가지 모드로 각각 촬영하였다. 모드 별로 OSLD 측정값을 얻고, 장기 흡수선량과 유효선량을 산출하였다. 또한 Alphard 3030의 3가지 모드에서는 선량면적곱측정계 DAP meter (VacuDAPTM; VacuTec Meßtechnik GmbH, Dresden, Germany)로 노출선량을 측정하였다. 이 값을 통해 PCXMC 소프트웨어(STUK, Helsinki, Finland)를 사용하여 몬테카를로 산출법으로 장기 흡수선량과 유효선량을 획득하였다. OSLD와 MC 두 방법 간의 유효선량 차이를 % 오차로 비교하였다. 결과: OSLD로 측정한 유효선량은 Alphard 3030 C 모드에서 가장 높았고 (599.0 µSv), CS 9300 Dual jaw 모드에서 가장 낮았다 (90.7 µSv). 조사야 크기가 10×10 cm으로 동일한 모드 간의 유효선량을 비교하면 Alphard 3030 (258.8 µSv), RAYSCAN α+ (213.8 µSv), CS9300 (90.7 µSv) 순서대로 높게 나타났다. 장기별 흡수선량은 콘빔시티의 종류와 상관없이 타액선에서 가장 높았고, 골수에서 가장 낮았다. Alphard 3030 콘빔시티의 OSLD 측정값과 MC 산출값을 비교해보면, 유효선량의 두 방법 간 퍼센트 오차는 9.8~23.4 %를 보였다. 두 방법 간의 장기별 흡수선량의 전반적인 분포는 Alphard 3030 콘빔시티의 검사 모드와 상관없이 비슷한 양상을 보였다. 결론: MC 산출값은 검사 모드에 따른 OSLD 측정값과 유사한 수준의 결과를 보였다. 따라서 MC 산출법은 임상에서 사용할 수 있는 편리한 방사선량측정 방법으로 기대된다. 중심단어: 몬테카를로방법, 선량측정법, 콘빔시티, 광자극발광선량계open박

고강도강 휨 부재의 비탄성 횡비틀림좌굴 거동

학위논문 (박사)-- 서울대학교 대학원 : 건축학과, 2015. 2. 이철호.This research focuses on the inelastic behavior of structural I-shaped members fabricated from 800MPa high strength steel (HSA800). HSA800, a new generation of high performance steel, produced by thermo-mechanical controlling (TMC) process, has the advantages to acquire the high strength as well high toughness and relatively low carbon equivalent value (CEV). Due to these features, the high strength steel has attracted considerable attention in the construction industry for its use in new structural applications with the help of the appropriate design and fabrication methods. However, due to the lack of sufficient research on the effects of the different post-yield range characteristics of the high strength steel to the structural behavior, the current code directly or indirectly restricts high strength steel by adopting limiting parameters such upper yield strength limit, upper yield-to-tensile (Y/T) strength ratio limit or a certain level of ductility capacity (rotation capacity). The primary target of this research is to experimentally and analytically quantify the effects of the post-yield range characteristics of mild and high strength steel on I-shaped flexural members. In addition, this study attempts to establish a methodology to provide adequate slenderness ratios to ensure inelastic lateral torsional buckling (LTB) strength and a certain level of rotation capacity, related to the existing AISC-LRFD specification and EC 3 code. This work consists of four major sections: stress-strain curve idealizations, estimation of in-plane rotation capacities, and analytical and experimental studies of inelastic LTB behaviors. In the stress-strain curve idealizations, tensile coupons of HSA800, SM570, and SM490 plates are tested and statistical regression curves were proposed to predict the Y/T strength ratio and tensile-to-yield (T/Y) strain ratio according to yield strength, which are pivotal values to idealize the initial portion of the stress-strain curve up to tensile strength. Four idealized material models (the traditional model (#1) and the Haaijer model (#2) for mild steelthe Ramberg-Osgood model (#3) for high strength steeland the Piecewise linear model (#4) for both steel grades) with properly assumed parameter values are suggested and numerically verified with the tensile coupon data. In the estimation of in-plane rotation capacities, a simplified method is proposed to calculate the in-plane rotation capacity at maximum moment of HSA800, SM570, and SM490 I-shaped members under uniform and moment gradient loading conditions by adopting the piecewise linear models. Under uniform moment loading condition, the in-plane rotation capacity is directly proportional to the T/Y strain ratio. On the other hand, at the moment gradient loading condition, three parameters including Y/T strength ratio, T/Y strain ratio, and yield plateau length together influence on the in-plane rotation capacity. Due to high Y/T strength ratio and low T/Y strain ratio of HSA800, the in-plane rotation capacity of HSA800 I-shaped member is inevitably low as compared to other grades (SM570 and SM490) of steel under moment gradient loading condition. Parametric studies were conducted to increase the rotation capacity level of the HSA800 I-shaped member under the moment gradient condition, demonstrating that lowering the Y/T strength ratio to 0.80 levels only does not ensure the satisfactory rotation capacity of the existing AISC-LRFD specification assumedthe increase of T/Y strain ratios is thus inevitably required. In the analytical studies of inelastic LTB behaviors, the methods to quantify the inelastic section stiffness (effective flexural, warping, and torsional rigidities of I-shaped member fabricated from mild and high strength steel), including the presence of the residual stresses, are proposed by applying the tangent modulus theories. This inelastic section stiffness is crucial to develop the LTB strength and rotation capacity curves of the I-shaped member under uniform and moment gradient loadings. After verifications of the derived strength and rotation capacity curves in current studies with the previous experimental data, parametric studies are conducted to evaluate the geometrical and material effects on the LTB capacity of I-shaped member. By comparing the results of the parametric models with the existing unbraced length limits specified in AISC-LRFD specifications, a methodology to design appropriate I-section geometry depending on the material selection of I-shaped member is proposed. In the experimental studies, three types of welded I-shaped specimens (type A-[G:H-250x150x15x15]-[M:Ho-775], type B-[G:H-400x150x15x15]-[M:Ho-775], and type C-[G:H-400x150x15x15]-[M:Hy-349-822], where [G:] indicates the cross section geometry[M:Ho] and [M:Hy] indicates the homogeneous and hybrid I-section respectively) were fabricated and tested under uniform moment to examine the geometrical and material effects of the I-section on LTB behaviors. All specimens failed by LTB, triggering a sinusoidal shape failure mode. The measured critical buckling strength and rotation capacity of both type A and type C specimens, where the effective section rigidities to plastic moment ratio are relatively high, satisfy the existing AISC-LRFD specification and EC 3 code. However, type B specimens, where a high height-to-width ratio is applied or the effective section rigidities to plastic moment ratio are relatively low, the current AISC-LRFD unbraced length limit would not give conservative rotation capacity values. By comparing the experimental data with the analytically developed buckling curves, it is shown that the curves well predict experimental LTB strength and rotation capacity values.Chapter 1. Introduction 1.1 Background 1.1.1 Production and mechanical properties of high strength steel 1.1.2 Specified limitation on high strength steels in building codes 1.2 Brief review of influence of post-yield range properties on member behavior 1.2.1 Post-yield range properties 1.2.2 In-plane behavior 1.2.3 Out-of-plane behavior 1.3 Limitation of recent studies and object of this study 1.3.1 Limitation of traditional stress-strain model to apply in high strength steel 1.3.2 Limitation of up-to-date theoretical and experimental researches 1.3.3 Objective of this study 1.4 Scope of work 1.4.1 Background 1.4.2 Development of analytical LTB model for I-shaped members 1.4.3 Development of LTB strength curve for homogeneous I-shaped member 1.4.4 Development of available rotation capacity curve for homogeneous I-shaped member 1.4.5 Development of LTB strength and rotation capacity curves for hybrid I-shaped member 1.5 Methodology 1.5.1 Experimental work 1.5.2 Theoretical work 1.6 Relevance of current studies 1.7 Summary Chapter 2. Previous Researches 2.1 Introduction 2.1.1 Major buckling phenomenon and the significance of uncoupling approach 2.1.2 Rotation capacity under uniform moment and moment gradient 2.2 Experimental studies of inelastic LTB behavior 2.2.1 Rotation capacity of I-beam under uniform moment 2.2.2 Rotation capacity of I-beam under moment gradient 2.3 Analytical studies of inelastic LTB behavior 2.3.1 I-Beams under uniform moment 2.3.2 I-Beams under moment gradient 2.4. Summary Chapter 3. Idealized Material Models and In-plane Rotation Capacity 3.1 Characteristics of stress-strain curves 3.1.1 Y/T strength ratio according to yield strength 3.1.2 T/Y strain ratio according to yield strength 3.2 Idealized material models 3.2.1 Traditional model 3.2.2 Haaijer model 3.2.3 Ramberg-Osgood model 3.2.4 Piecewise-linear model (Tri-linear, Bi-linear) 3.3 In-plane rotation capacity 3.3.1 Overview and assumption 3.3.2 In-plane rotation capacity at member maximum moment 3.4 Summary Chapter 4. Analytical Studies of Inelastic LTB Behaviors 4.1 Derivation of inelastic section rigidities for analyzing inelastic buckling 4.1.1 Tangent modulus theory and its application 4.1.2 Inelastic section rigidities in ideal I-section 4.1.3 Residual stress in I-section 4.1.4 Effects of residual stresses on inelastic section rigidities of I-beam 4.1.5 Summary 4.2 LTB strength under uniform moment 4.2.1 Overview of LTB under uniform moment 4.2.2 Analytical parametric studies 4.2.3 Detailed approach to derive unbraced length limit for achieving plastic moment 4.2.4 Simplified approach to derive unbraced length limit for achieving plastic moment 4.2.5 Summary 4.3 Available rotation capacities (governed by LTB) under uniform moment 4.3.1 Description of the behavior 4.3.2 Derivation of rotation capacity curve under uniform moment via inelastic section rigidities 4.3.3 Validation of the analytically developed rotation capacity curve with previous experiments 4.3.4 Analytical parameter studies 4.3.5 Detailed approach to derive unbraced length limit for target rotation capacity 4.3.6 Simplified approach to derive unbraced length limit for target rotation capacity 4.3.7 Summary 4.4 LTB strength under moment gradient 4.4.1 Overview of LTB under moment gradient 4.4.2 Simplified T-column approach to derive unbraced length limit for achieving plastic moment 4.4.3 Summary 4.5 Available rotation capacitys under moment gradient 4.5.1 Description of the behavior 4.5.2 Derivation of rotation capacity curve under moment gradient via inelastic section rigidities 4.5.3 Simplified T-column approach to derive unbraced length limit for target rotation capacity 4.5.4 Summary Chapter 5. Experimental Buckling Studies 5.1 Overview of the experimental study 5.1.1 Mechanical properties 5.1.2 Instrumentation plan for measurement 5.1.3 Data processing method 5.1.4 Description of test parameter 5.2 Experimental test results 5.2.1 Specimen Type A: [G:H-250x150x15x15]-[M:H0-775] 5.2.2 Specimen Type B: [G:H-400x150x15x15]-[M:H0-775] 5.2.3 Specimen Type C: [G:H-350x150x30x25]-[M:Hy-349-827] 5.3 Evaluation of the experimental results 5.3.1 Comparison with the code prediction 5.3.2 Comparison with the previous experiments 5.3.3 Comparison with the analytically developed buckling curves 5.4 Summary Chapter 6. Conclusions ReferencesDocto

다양한 암종에서 메틸화 변이 정도와 종양 면역원성 사이 상관관계에 관한 연구

학위논문(석사)--서울대학교 대학원 :의과대학 의학과,2020. 2. 김동완.While genomic alterations in tumors, such as somatic mutations or somatic chromosomal instability, have been reported as reliable biomarkers in immune-oncology, associations between the methylation landscape and tumor immunogenicity is unknown. I sought to find biomarker related to methylation to represent tumor immunogenicity. I used The Cancer Genome Atlas (TCGA) pan-cancer database (N~8,000) to define methylation burden (MetB) as the number of hypermethylated or hypomethylated CpG sites to represent the degree of aberrant methylation. I comprehensively investigated the association of MetB with cytolytic activity score, calculated by mean of GZMA and PRF1 expression levels, and other various genomic profiles. The degree of methylation aberrancy correlated with methylation subtypes defined in previous literatures. It also showed negative correlation expression of molecules coordinating immune recognition of tumors. The pan-cancer analysis showed that MetB was negatively correlated with cytolytic activity score (ρ = -0.37, p < 0.001), independent of mutation burden and chromosomal instability. The negative correlation was consistent in the external cohort of lung adenocarcinoma and low grade glioma (Spearman ρ = -0.41, p < 0.001 and ρ = -0.34, p = 0.014, respectively). MetB also had negative correlation with interferon-gamma signatures and was lower in highly immunogenic subtypes of immune landscape. Furthermore, patients with bottom 20% MetB showed longer progression free survival to ipilimumab in TCGA melanoma patients (p = 0.029). These findings emphasize the importance of methylation aberrancy for tumors to evade immune surveillance and warrant further development of methylation biomarker.체세포 돌연변이 또는 체세포 염색체 불안정성과 같은 종양에서의 유전자 변이가 종양면역치료에서 신뢰할 수 있는 바이오마커로 보고되어 있지만, 유전자 메틸화의 변화와 종양 면역원성 사이의 연관성은 알려져 있지 않다. 본 연구에서는 종양 면역원성을 나타내는 메틸화와 관련된 바이오마커를 찾고자 한다. TCGA (The Cancer Genome Atlas)의 약 8000여개에 달하는 전체 암종 데이터베이스를 활용하여, 메틸화 변이 정도를 검체가 가지고 있는 과 메틸화 혹은 저 메틸화 된 CpG 부위의 수로 정의하였다. 이렇게 정의된 메틸화 변이 정도와 GZMA와 PRF1 유전자의 발현의 평균값인 세포 용해활성도를 비롯하여 다양한 종양 면역원성과의 연관성을 포괄적으로 조사하였다. 메틸화 변이 정도는 기존의 문헌에 정의되었던 메틸화 분류와 관련성이 있었다. 또한, 종양 면역 인식에 관여하는 분자의 발현과 음의 상관관계가 있는 것도 확인하였다. 전체 암종 분석을 하였을 때, 메틸화 변이 정도는 세포 용해활성도와 음의 상관 관계(ρ = -0.37, p <0.001)가 있음을 확인하였고, 이는 체세포 돌연변이 개수 및 염색체 불안정성과 독립적으로 연관이 있음을 확인하였다. 이러한 음의 상관 관계는 TCGA 이외에 폐선암종 및 저등급 뇌교종으로 각각 구성된 외부 코호트에서도 확인되었다 (ρ = -0.41, p <0.001 및 ρ = -0.34, p = 0.014). 메틸화 변이 정도는 또한 인터페론 감마 유전자 시그니처와 음의 상관관계를 보였으며, 면역원성이 높은 아형에서 더 낮은 것이 확인되었다. 또한, TCGA 흑색종 환자 중 이필리무맙 면역치료를 받은 환자들을 대상으로 보았을 때, 하위 20%의 메틸화 변이를 갖는 환자들에서 더 긴 무질병진행생존을 보였다 (p = 0.029). 그리고 면역 반응과 관련된 유전자 프로모터의 과 메틸화 및 저 메틸화는 세포 용해활성점수에 유의하게 영향을 미쳤다. 이러한 결과는 종양의 메틸화 변이 정도가 종양의 면역 회피에 중요하다는 것을 강조하며, 차후 이와 관련된 바이오마커의 개발이 필요함을 시사한다.Abstract 1 List of Figures 5 List of Tables 7 Introduction 8 Results 10 Defining the degree of methylation aberrancy and its correlation with methylation subtypes 10 Hypermethylation in promoter of CD274 (PD-L1) and human leukocyte antigen correlates decreased corresponding RNA expression 14 Negative correlation of methylation burden with immunogenicity in the tumor microenvironment 21 Methylation aberration in addition to mutation burden and copy number alterations predicting immunogenicity 36 Selection of CpG sites to assess potential of methylation aberrancy as a biomarker 39 Discussion 41 Conclusion 44 Methods 45 Dataset acquisition 45 Determining β-score cutoffs and definition of methylation burden 46 Promoter methylation status and expression determination 47 Genomic profile definition 47 Selection of CpG sites 48 Statistical analysis 48 References 50 초록 57Maste

The Influence of Total Body Irradiation of X-rayon The Survival of Homologous Skin Grafts in Rats.

The behavior of the homologous skin grafts in rats irradiated with sublethal dosis of X-ray was studied. Wistar albino rats were used as recipients and donors were Long-Evans hooded rats. The sublethal dosis of total body irradiation of X·ray to the normal Wistar rats was approximately 600r-650 r and 500r was estimated to be sublethal dosis. The skin homografts of 2.0cm.x 2.0 cm. from hooded donors to untreated Wister recipients survived for 7 to 10days, on average 8. 5 days, followed by the typical pattern of the skin homograft re ection; whereas of the 15sublethally irradiated ani~ mals 12showed prolonged survival (4 to weeks) of the grafts from hooded donors, which were ultimately replaced by the host tissue with the chronic rejection pattern, none of them survived permanently

Effect of Yield Strength on Inelastic Lateral Instability and Rotation Capacity of Continuous Steel Beams

학위논문(석사) --서울대학교 대학원 :건축학과,2010.2.Maste