유기용매 리그닌의 구조적 특성이 리그노-바이오플라스틱의 열적·기계적 특성에 미치는 영향

학위논문 (박사) -- 서울대학교 대학원 : 농업생명과학대학 산림과학부(환경재료과학전공), 2021. 2. 최인규.In this study, the effect of the structural characteristics of ethanol organosolv lignin (EOL) on the thermal and mechanical properties of ligno-bioplastics was investigated. A response surface methodology (RSM) based on central composite design (CCD) was adopted to investigate the influence of the extraction conditions on the structural characteristics of EOL. Via the RSM, EOL with a low molecular weight, low polydispersity index (PDI), high phenolic hydroxyl content, and condensed structure was obtained under harsh extraction conditions. The correlation between the structural characteristics of EOL and the severity of the extraction conditions was confirmed by introducing the combined severity factor (CSF), and a clear correlation consistent with the RSM results was derived. In addition, the structural characteristics of the EOL derived under different extraction conditions influenced its thermal properties. The EOL with a low molecular weight, high phenolic hydroxyl group content, and condensed structure, exhibited high thermal stability while delaying the thermal decomposition with a high glass transition temperature (Tg). To predict the weight reduction rate of EOL at 300 °C, the regression model (R2 = 0.837) was suggested. In accordance with the model, the lower the molecular weight of the EOL, the lower the rate of thermal degradation of EOL was expected. Meanwhile, the EOL–PLA thermo-bioplastics prepared using three types of EOL (EOL extracted under low-severity (LL), moderate-severity (ML), and high-severity (HL) conditions) exhibited improved thermal stability compared to neat PLA. According to the thermal properties of EOL, the EOL–PLA bioplastic formed with HL exhibited exceptional thermal stability. The bioplastics had different mechanical properties depending on the types of EOL. The tensile strength of the bioplastics tended to decrease as the content of lignin in the bioplastics increased. Conversely, the nominal strain at break of the bioplastics exhibited a different tendency depending on the types of EOL. Oxypropylation of EOL was employed to improve the thermoplasticity and compatibility with PLA. Three types of EOL (LL, ML, and HL) with different structural characteristics were modified by propylene oxide (PO). During the oxypropylation, the degree of substitution (DS) and the degree of polymerization (DP) of the propyl side chain were affected by the distribution of the hydroxyl groups in the initial EOL structure. The HL with a high aromatic hydroxyl group content (4.31 mmol/g) exhibited a high DS (0.77), and the LL with a high aliphatic hydroxyl group content (2.94 mmol/g) exhibited a high DP (11.17). Moreover, the oxypropylation of EOL enhanced its thermoplasticity. In particular, a new Tg (from 55 to 60 °C) and melting point were observed for the oxypropylated LL and ML. In addition, the compatibility of EOL with PLA was successfully improved by oxypropylation, which was supported by a slick and flat surface structure observed in the bioplastics with oxypropylated LL and ML. The increased compatibility of EOL with PLA induced an increase in the tensile strength of the oxypropylated EOL–PLA bioplastic to a similar level to that of the neat PLA, and the nominal strain was also increased to a higher level than that of the neat PLA. In addition, the Tg of the EOL–PLA bioplastic was increased compared to that of the neat PLA in a thermodynamic perspective, implying that the mechanical properties of the oxypropylated EOL–PLA bioplastic were improved at temperatures above the Tg of the neat PLA. Thermosetting lignopolyurethanes with different thermal and mechanical properties depending on the types of EOL were prepared. The structural characteristics and properties of lignopolyurethane highly depended on the structural characteristics of oxypropylated EOL. The oxypropylated EOL with a high hydroxyl group content showed a high reaction rate. All of the lignopolyurethanes exhibited increased thermal stability at low temperatures compared to those of the corresponding oxypropylated EOLs, whereas at high temperatures, the thermal properties of lignopolyurethane depended on the thermal properties of the corresponding initial EOLs. In addition, the structural characteristics of the EOL had a significant effect on the mechanical properties of the lignopolyurethane film. The oxypropylated EOL with a high average hydroxyl content enabled to form a lignopolyurethane film with a high crosslink density due to its high reactivity. The lignopolyurethane film with a high crosslinking density exhibited competent tensile strength. Consequently, the thermoplastic and thermosetting properties of EOL were imparted through chemical modification methods based on the correlation between the structural characteristics and properties of the EOL. The thermal and mechanical properties of the ligno-bioplastics were found to be significantly influenced not only by the chemical modification of EOL but also by the structural characteristics of lignin, the raw material.본 연구에서는 유기용매 리그닌의 구조적 특성이 리그노-바이오플라스틱의 열적·기계적 특성에 미치는 영향을 조사하였다. 먼저 에탄올 유기용매 리그닌(EOL)의 구조적 특성에 대한 추출 조건의 영향은 반응표면분석법(RSM)을 이용하여 조사하였다. 설정된 RSM 분석 범위 내에서 추출 조건이 가혹할수록 낮은 분자량, 낮은 다분산도, 높은 방향족 수산기 함량 및 축합된 구조를 가진 EOL이 생산되는 경향을 보였다. 이러한 경향은 추출 조건의 가혹도 지수(CSF)를 도입하여 EOL의 구조와의 명확한 상관관계를 도출함으로써 확인되었다. 또한 다양한 추출 조건에서 파생된 EOL의 구조와 열적 특성 간의 상관관계를 평가하였다. EOL의 열적 특성은 분자량 및 방향족 수산기 인자와 뚜렷한 상관 관계를 보였다. 낮은 분자량, 높은 방향족 수산기 함량 및 축합된 구조를 갖는 EOL은 높은 유리전이온도(Tg), 낮은 열분해 시작 온도 및 초기 분해 속도를 나타냈다. EOL의 구조와 열적 특성 간의 상관관계 결과를 바탕으로 EOL의 중량 감소율 예측을 위한 회귀 모델(R2 = 0.837)이 제시되었으며, EOL의 분자량이 낮을수록 300 °C에서의 열분해가 느리게 발생할 것으로 예측되었다. 추출 조건의 가혹도가 서로 다른 EOL(LL(#5, 낮은 가혹도 조건에서 추출된 EOL), ML(#16, 중간의 가혹도 조건에서 추출된 EOL), HL(#4, 높은 가혹도 조건에서 추출된 EOL))을 사용하여 제조된 EOL-PLA 바이오플라스틱은 사용된 EOL 종류에 따라 다른 열적·기계적 특성을 나타냈다. EOL-PLA 바이오플라스틱은 순수 PLA에 비해 우수한 열안정성을 나타냈으며, HL를 사용하여 제조한 EOL-PLA 바이오플라스틱은 다른 바이오플라스틱 보다 높은 열분해 시작점과 최대 분해 온도를 나타냈다. EOL-PLA 바이오플라스틱의 인장 강도는 리그닌 함량이 증가함에 따라 감소하는 경향을 나타냈다. 반면 EOL-PLA 바이오플라스틱의 공칭변형률은 EOL에 따라 다른 경향을 보였다. 한편, EOL의 열가소성과 바이오폴리이스터와의 상용성을 개선하기 위해 옥시프로필화를 도입하였다. 옥시프로필화는 구조적 특성이 다른 세 종류의 EOL(LL, ML 및 HL)을 이용하여 EOL의 수산기와 프로필렌 옥사이드(PO)의 다양한 몰비(1:1, 1:2 및 1:5)로 실시했다. 옥시프로필화 과정에서 초기 EOL의 수산기 분포는 프로필 측쇄의 치환도와 중합도에 크게 영향을 미쳤으며, 방향족 수산기 함량이 높은 HL(4.31 mmol/g)은 높은 치환도(0.77)를 보였고, 지방족 수산기 함량이 높은 LL(2.94 mmol/g)은 높은 중합도(11.17)를 나타냈다. 옥시프로필화는 EOL의 열가소성을 향상시켰으며, 구조적 특성과 초기 EOL에 따라 서로 다른 열적 특성을 나타냈다. 특히 옥시프로필화된 LL과 ML은 55-60 °C 범위의 새로운 Tg가 생성되었으며, 용융점이 관찰되었다. 또한 개선된 열가소성을 기반으로 EOL과 PLA의 상용성이 옥시프로필화에 의해 향상되었다. 옥시프로필화 LL 및 ML을 이용한 바이오플라스틱에서는 열가소성 및 상용성이 개선되어 초기 EOL을 이용한 바이오플라스틱에 비해 매끄럽고 평평한 표면 구조가 관찰되었다. EOL의 개선된 PLA와의 상용성 및 열가소성은 바이오플라스틱의 인장강도를 PLA와 유사한 수준으로 향상시켰으며 공칭변형률을 PLA보다 높은 수준으로 증가시켰다. 동역학적 열분석 결과, 옥시프로필화 EOL의 첨가는 PLA의 Tg를 향상시켜 물리·화학적 특성을 개선하였다. 또한 구조적 특성이 서로 다른 옥시프로필화 리그닌을 이용하여 열적·기계적 특성이 다른 리그노폴리우레탄을 제조하였다. 리그노폴리우레탄은 옥시프로필화 EOL과 헥사메틸렌 디이소시아네이트(HDI)를 이용하여 합성하였으며, 옥시프로필화 EOL의 구조적 특성은 리그노폴리우레탄의 반응성 및 열적·기계적 특성에 영향을 미쳤다. 구조 내 수산기 함량이 높은 옥시프로필화 EOL은 높은 반응 속도를 나타냈다. 리그노폴리우레탄의 초기 열안정성은 각각의 상응하는 옥시프로필화 EOL에 비해 증가하였으며 350 °C 이상의 고온에서 리그노폴리우레탄의 열적 특성은 초기 EOL의 열적 특성에 따라 다르게 나타났다. 또한, 옥시프로필화 EOL의 구조적 특성은 리그노폴리우레탄 필름의 기계적 물성에 큰 영향을 미쳤다. 수산기 함량이 높은 옥시프로필화 EOL은 높은 반응성으로 인해 리그노폴리우레탄의 가교밀도를 증가시켜 높은 인장강도를 야기했다. 결론적으로 EOL의 구조와 물성 간의 상관관계를 바탕으로 옥시프로필화를 통해 EOL의 열가소성을 부여하여 EOL-PLA 바이오플라스틱을 제조하였으며 우레탄 합성을 통해 열경화성을 부여하여 리그노폴리우레탄 필름을 제조하였다. 이때 초기 EOL의 구조적 특성은 리그노-바이오플라스틱의 열적·기계적 특성에 유의미한 영향을 미쳤다.Chapter 1 1 Introduction 1 1. Background 2 1.1. Lignin as a bioplastic material 2 1.1.1. Bioplastics as alternatives to petroleum-based plastics 2 1.1.2. Drawbacks of thermoplastics (biopolyester) and thermosetting (biopolyurethane) bioplastics 6 1.1.3. Lignin as an additive or precursor of bioplastic materials and ligno-bioplastic 9 1.2. Bottlenecks of lignin utilization for bioplastics applications derived from its structure and thermal properties 12 1.2.1. Types of lignin based on the extraction processes and organosolv lignin 12 1.2.2. Diversity of the structural characteristics and thermal properties of lignin 16 1.2.3. Bottlenecks of lignin utilization in bioplastic production 20 1.3. Strategies for improving the commercial utilization of lignin in bioplastic production 21 1.3.1. Selective production of lignin with desirable structure 21 1.3.2. Compatibilization of lignin and thermoplastic resins by functionalization 23 1.3.3. Macromoleculization of lignin with bifunctional monomers 26 2. Objectives 27 3. Literature review 30 3.1. Investigation of the correlation between the structure and properties of lignin for its application in bioplastic production 30 3.1.1. Control of the lignin structure by adjusting the extraction conditions 30 3.1.2. Thermal properties of lignin based on its structure 33 3.2. Unmodified lignin–PLA bioplastics 36 3.2.1. Mechanical properties of lignin–PLA bioplastics 36 3.2.2. Thermal properties of lignin–PLA bioplastics 38 3.3. Chemical modification of lignin for lignin–PLA bioplastics 39 3.3.1. Lignin graft copolymer 39 3.3.2. Macromoleculization 43   Chapter 2 46 Thermal and mechanical properties of EOLs and EOL–PLA bioplastics 46 1. Introduction 47 2. Materials and methods 50 2.1. Ethanol organosolv lignin (EOL) preparation 50 2.1.1. Raw materials 50 2.1.2. Conditions for EOL extraction 50 2.1.3. EOL extraction process 53 2.2. Structural characteristics of the EOL 54 2.2.1. Molecular weight 54 2.2.2. Hydroxyl group content 54 2.2.3. Intramolecular coupling structure of EOL 55 2.3. Thermal properties of EOL 57 2.3.1. Thermal decomposition characteristics of EOL 57 2.3.2. Glass transition temperature of EOL 57 2.3.3. Statistical analysis 57 2.4. EOL–PLA bioplastic 59 2.4.1. Preparation of EOL–PLA bioplastics 59 2.4.2. Thermal properties of EOL–PLA bioplastics 59 2.4.3. Mechanical properties of EOL–PLA bioplastics 59 3. Results and Discussion 60 3.1. Structural characteristics of EOL based on the extraction conditions 60 3.1.1. Molecular weight and PDI 61 3.1.2. Hydroxyl group content 68 3.1.3. Intramolecular coupling structure 75 3.1.4. Correlation between CSF of extraction condition and the structural characteristics of EOL 81 3.2. The thermal properties of EOL depending on its structural characteristics 84 3.2.1. Statistical analysis of the correlation between weight loss at 300 °C and the structural characteristics of EOL 84 3.2.2. Thermal decomposition characteristics and glass transition temperature of three types of EOL 91 3.3. The properties of the EOL–PLA bioplastics depending on the structural characteristics of EOLs 94 3.3.1. Thermal properties of the EOL–PLA bioplastics depending on types of EOL 94 3.3.2. Mechanical properties of the EOL–PLA bioplastics depending on types of EOL 97 4. Summary 101   Chapter 3 103 Chemical modification of EOL for improving thermoplasticity and compatibility in EOL–PLA bioplastics 103 1. Introduction 104 2. Materials and methods 107 2.1. EOL preparation 107 2.1.1. Raw materials 107 2.1.2. EOL extraction 107 2.1.2. Properties of EOL based on the extraction condition 110 2.2. Oxypropylated lignin preparation 112 2.2.1. Oxypropylation of three types of EOL 112 2.2.2. Properties of the oxypropylated EOLs in relation to their structural characteristics 113 2.3. Oxypropylated EOL–PLA bioplastics 116 2.3.1. Preparation of the EOL–PLA bioplastics 116 2.3.2. Morphologies of the EOL–PLA bioplastics 116 2.3.3. Properties of oxypropylated EOL–PLA bioplastics based on its structural characteristics 116 3. Results and Discussion 118 3.1. Structural characteristics of the oxypropylated EOL 118 3.1.1. Molecular weight of the oxypropylated EOLs 118 3.1.2. Hydroxyl group and modified methyl group content of the oxypropylated EOLs 123 3.1.3. DS and DP of the oxypropylated EOLs 131 3.2. Thermal properties of oxypropylated EOLs based on its structural characteristics 134 3.2.1. Thermal decomposition behavior of the oxypropylated EOL based on its structural characteristics 134 3.2.2. DSC analysis of the oxypropylated EOL based on its structural characteristics 138 3.3. The properties of the oxypropylated EOL–PLA bioplastic 143 3.3.1. Morphologies of the EOL–PLA bioplastics 143 3.3.2. Thermal properties of the oxypropylated EOL–PLA bioplastics 146 3.3.3. Mechanical properties of the oxypropylated EOL–PLA bioplastics 151 3.3.4. Thermodynamic properties of the oxypropylated EOL–PLA bioplastics 157 4. Summary 160   Chapter 4 162 Preparation and characterization of lignopolyurethanes using different types of EOL 162 1. Introduction 163 2. Materials and methods 166 2.1. EOL and oxypropylated EOL preparation 166 2.1.1. Raw materials 166 2.1.2. Extraction of EOL 166 2.1.3. Oxypropylation of EOL 166 2.2. Lignopolyurethane preparation 169 2.2.1. Urethane synthesis for lignopolyurethane 169 2.2.2. Lignopolyurethane film preparation 169 2.3. Structural characteristics of lignopolyurethane 171 2.3.1. Elementary analysis of lignopolyurethane 171 2.3.2. FT-IR analysis of lignopolyurethane 171 2.4. The properties of lignopolyurethane 172 2.4.1. Thermal properties of lignopolyurethane 172 2.4.2. Mechanical properties of lignopolyurethane film 172 3. Results and Discussion 173 3.1. Structural characteristics of lignopolyurethane 173 3.1.1. Urethane synthesis for lignopolyurethane 173 3.1.2. FT-IR analysis of lignopolyurethane 178 3.2. Properties of lignopolyurethane 181 3.2.1. TGA of lignopolyurethane 181 3.2.2. DSC analysis of lignopolyurethane depending on its structural characteristics 184 3.3. Lignopolyurethane film 187 3.3.1. Crosslinking density of lignopolyurethane film 187 3.3.2. Mechanical properties of the lignopolyurethane film 189 4. Summary 194   Chapter 5 196 Concluding remarks 196 References 202 초 록 218Docto

Phylogenetic Positioning of a Strongyloides stercoralis Isolate Recovered from a Korean Patient and Comparison with Other Asian Isolates

Strongyloidiasis is caused by Strongyloides stercoralis and is one of the most neglected tropical diseases in tropical and subtropical regions. Although several strongyloidiasis cases have been reported in Korea, genetic analysis of Korean isolates is still incomplete. In this study, a parasite was isolated from a 61-year-old man diagnosed with strongyloidiasis during the treatment of lymphoma on his retroperitoneal lymph node. Diffuse symmetric wall thickening from the ascending to descending colon and a nematode-infected intestine was observed following microscopic examination. Genomic DNA was isolated from a patient tissue block, and S. stercoralis was identified by PCR and sequencing (18S rDNA). In order to determine phylogenetic location of a Korean isolate (named KS1), we analyzed cox1 gene (500-bp) and compared it with that from 47 previous S. stercoralis isolates (28 human isolates and 19 canid isolates) from Asian countries. Our results showed that phylogenetic tree could clearly be divided into 5 different groups according to hosts and regions. KS1 was most closely related with the Chinese isolates in terms of genetic distance.ope

Research on the Architectural Experiments and Alteration of Protestant Churches in Early Modern Seoul

학위논문 (석사)-- 서울대학교 대학원 : 건축학과, 2015. 2. 전봉희.본 연구는 근대 초기 서울의 개신교 교회의 도성 내 확산 과정과 개신교 교회의 다양한 건축 실험 및 변화를 고찰하는 것에 목적이 있다. 이를 위해 본 연구에서는 1884년 개신교 선교가 시작된 이래로 도성 내에 장로교, 감리교 소속의 교회들이 확산되어 입지하는 양상에 주목하였다. 또한 1897년 정동제일교회를 시작으로 건립되게 된 대형 예배당들의 평면과 구조에 있어서의 건축적 실험과 그에 따른 영향과 변화의 관계를 확인하였다. 근대기 교회 건축에 대한 연구는 실물이 대부분 현존하고 있는 천주교 성당을 중심으로 연구가 진행되어 왔다. 개신교 교회 건축은 근대기에 천주교 성당만큼이나 사회적으로나 문화적으로나 건축적으로 서울에서 큰 영향을 끼쳤음에도 불구하고 전쟁 및 재건축 등으로 인한 실물 사료 등의 부족으로 깊이 있는 연구가 진행되지 못하였다. 하지만 최근의 근대기 개신교 교회 건축에 대한 새로운 자료의 발굴 및 각 교회의 교회사 편찬, 선교사들의 일기 및 편지류 등의 번역, 외국 아카이브 자료에 대한 접근의 용이성 등은 현재 많은 교회들이 실존하지 않음에도 불구하고 당시의 개신교 교회의 도시적 특성 및 건축적 특성 등을 새롭게 재조명할 수 있는 계기가 된다고 할 수 있다. 교회 입지 및 확산 과정은 장로교∙감리교 정동 선교기지 시기를 거친 후에 도성 내로 확산하게 된다. 먼저 교회는 일반 대중과의 접촉이 용이한 곳과 병원 및 학교 시설이 세워질 수 있는 위치에 자리 잡게 된다. 초기에 세워진 교회들은 4대문과 시장 주변으로 세워짐을 알 수 있다. 그 이후의 교회의 확산은 선교부 사이에 맺은 선교지 분담 정책과 3각 거점 계획에 의해 도성 내 지역적 거점을 확보하게 된다. 많은 선교부 소속의 교회들이 서울에 세워졌음에도 서로 겹치지 않고 고르게 분포될 수 있었던 것은 정식적으로 발효되지는 않았지만, 선교사들 사이에서 협정한 선교지 분담정책의 영향이다. 또한 교회 내의 신자간 갈등과 지역갈등이 교회 확산 및 입지에 한 축을 담당하게 되었다. 이는 선교지 개척에 소외되었던 북쪽의 양반 계층 거주 지역에 교회가 세워지도록 하는 역할을 하였다. 한편, 대형 예배당이 건축되기 시작한 이후의 개신교 교회의 건축 실험은 평면과 구조를 통해 다양한 양상으로 드러나게 된다. 평면에 있어서는 미국교회의 설계 도면의 수용과 적응, 한국인 건축가에 의한 삼랑식 평면의 실험, 2층의 갤러리 공간을 고려한 장방형의 평면의 도입으로 나타난다. 구조적 측면에 있어서는 가위형 가새 트러스(sissor-bracing truss)가 정동제일교회를 짓기 위해 보내온 도면을 통해 도입된 것으로 추정되며, 기울어진 천장에 중앙부분만 평평한 특징을 보인다. 왕대공 트러스(king post roof truss)는 안동교회에 적용이 되었고, 인장력을 받는 대공을 목재를 대신하여 철제로 사용한 특징을 보인다. 이는 왕대공 트러스가 갖는 경간의 한계를 극복하기 위한 시도로 생각된다. 쌍대공 트러스(queen post roof truss)는 승동교회에 적용이 되었다. 근대 시기에 쌍대공 방식은 드문 경우이다. 또한 쌍대공 트러스에서 일반적으로 사용되는 평천장 구조를 택한 것이 아니라 천장 보의 일부를 이동하여 천장이 움푹 파인 구조물을 시도하였다는 점에서 의의가 있다고 하겠다. 마지막으로 근대기 서울의 교회 건축을 둘러싼 여러 시도들은 다른 지역의 교회 및 학교 건물에 영향을 주었고, 이후 시기에도 영향을 주게 된다. 평면에 있어서는 인천의 내리교회가 정동제일교회와 마찬가지로 미국식 평면을 도입하여 건축하였다. 평양의 남산현 교회는 외형, 구조, 평면 등에서 상동교회와 매우 유사한 건축적 특성을 보인다. 장로교의 정방형 평면은 동시기의 목포의 양동교회에서 동일하게 나타나지만, 이후 시기의 건물에서는 정방형보다는 장방형의 평면으로 귀결되는 특징을 보인다. 구조의 측면에 있어서는 가위형 가새 트러스가 정동제일교회에 도입된 이후로 상동교회 등의 감리교 교회 및 학교 건물 등에 꾸준하게 활용되었고, 교파를 뛰어넘어 장로교와 성결교의 학교 및 교회 건물에서도 적용된 것을 확인할 수 있다.This studys purpose is to trace the location of early Protestant churches in Seoul during 1885-1910 and to reveal the spreading patterns of them. Furthermore, it aims for analyzing their architectural experiments and the alterations over the time period. Specifically, this study focuses on how Presbyterian churches and Methodist churches spread within Seoul city walls since the Protestant churches started missionary works in 1884. Starting with Chungdong First Methodist Church built in 1897, the changes in the floor patterns and roof structureof large chapels due to various architectural experiments and alterations were scrutinized. The study of modern churches in Korea has mainly focused on existing Catholic churches so far. Even though the Protestant churches played a critical role in shaping modern Seouls cityscape in both social and cultural contexts as Catholic churches did, there has been a limited number of studies about them because of the lack in resources and existing buildings due to Korean war and continuous reconstructions. However, as new resources for early modern Protestant churches have been collected recently and an easier access to archived materials of other countries and missionaries journals and letters was provided, a better environment for studying urban and architectural characteristics of Protestant churches at that time has been created. Missionary works of Protestant churches began with the construction of Presbyterian and Methodist mission compounds in Jeong-dong where the foreign legations, including the U.S. legation, were located. However, since it was hard to be in contact with the general public at Jeong-dong, they eventually moved out to new areas in Seoul. First, churches settled in the area where they could easily contact with the general public and find enough space for hospital and school facilities. Churches of the early period were built around the four main gates of old Seoul and big markets. Second, according to the mission field apportionment policies and triangular foothold plans set by the central missionary, both Presbyterian and Methodist branches could procure regional footholds in Seoul boundary. Because of that mission field apportionment policies, they were evenly distributed within Seoul in spite of drastic growth. Furthermore, dividing Seoul into 3 or 4 sections and distributing each to the responsible missionaries had a huge impact on the spreading pattern. Lastly, both inner and outer struggles within the believers or among the local regions contributed to the location and spread of churches. This trend eventually led toward the church construction in the northen part of Seoul where was mainly the residential areas of gentry and therefore, previously excluded from the missionary works. Meanwhile, as the large chapels were built, Protestant churches began to attempt various architectural experiments, trying different floor plans and roof truss structures. Main characteristics of floor plans include the application and adaptation of the floor plans of American churches, the experiment of basilican brick churches by Korean architects, and the introduction of square-shaped plans considering the use of second floor gallery. In terms of structures, Scissors-shaped bracing truss was introduced when Chungdong First Methodist church was built, and the central parts shape was flat while the sides were inclined. King post roof truss was applied for Andong Presbyterian church, in which the vertical member in charge of tension force was replaced by the iron one instead of wood. Grounds for this feature may be to overcome the limitations in the span length of king post roof truss. Queen post roof truss was used in Seungdong Presbyterian church, and it was a rare type in the early modern period. Seungdong Presbyterian churchs case is significant because some of beams were moved to the side to create a new type of ceiling structure while flat ceiling structure was commonly used for queen post roof truss originally. Last, the architectural experiments and alterations of Protestant churches in early modern Seoul ultimately influenced the architecture of churches and schools in other regions, and these impacts have been continued afterwards. For the floor plans, Naeri Methodist church in Incheon and Chungdong First Methodist church both applied an American style plans. Namsanhyun Methodist church in Pyoung-yang is very similar to Sang-dong Methodist church in its appearance, structure, and plan. A square-shaped plan for Presbyterian churches appeared in Yangdong Presbyterian church, but the use of square-shaped plan declined as the rectangular plans were used. In the structural aspect, scissors-shaped bracing truss, which was first applied in Chungdong First methodist church, began to be widely used in school buildings and methodist churches, including Sangdong Methodist church. It is even found in the Presbyterian churches and the Holiness churches after all.Ⅰ. 서 론 1 1.1 연구의 배경과 목적 1 1.2 연구의 대상과 방법 3 1.3 선행연구의 분석 5 Ⅱ. 개신교 교회의 입지와 확산 11 2.1 정동 선교기지의 설립 11 2.2 교회의 입지와 확산 19 2.2.1 정동 선교기지 외부로의 진출 19 2.2.2 선교지 분담 정책과 지역별 분포와 확산 26 2.2.3 교파 별 교회 확산 35 Ⅲ. 초기 개신교 교회 건축의 특성 39 3.1 개신교 교회 건축의 특성 40 3.1.1 신의 집과 신자들의 집회소로서의 교회 건축 40 3.1.2 내부 공간의 특성 45 3.2 대형 예배당의 등장과 확산 51 3.2.1 천주교 성당 건축의 영향 54 3.2.2 교인수 증가 56 3.2.2 새로운 프로그램의 도입 60 3.3 교파의 특성에 따른 건축 활동의 차별화 63 3.2.1 감리교 63 3.2.2 장로교 66 Ⅳ. 개신교 교회의 건축적 실험과 영향 71 4.1 평면에서의 실험 72 4.1.1 미국 설계 도면을 통한 십자형 평면의 도입 72 4.1.2 한국인 건축가에 의한 삼랑식 평면의 실험 81 4.1.3 장로교 교회 건축에 도입된 정방형의 평면 87 4.2 지붕 구조에서의 실험 97 4.2.1 가위형 가새 트러스 구조(scissor-bracing) 100 4.2.2 왕대공 지붕 트러스 구조(king post roof truss) 105 4.2.3 쌍대공 지붕 트러스 구조(queen post roof truss) 111 4.2 실험의 영향과 교회 건축의 변화 115 4.2.1 다른 지역으로의 영향 115 4.2.2 이후 시기로의 영향 123 Ⅴ. 결론 135Maste

Parasites and blood-meal hosts of the tsetse fly in Tanzania: a metagenomics study

Background: Tsetse flies can transmit various Trypanosoma spp. that cause trypanosomiasis in humans, wild animals, and domestic animals. Amplicon deep sequencing of the 12S ribosomal RNA (rRNA) gene can be used to detect mammalian tsetse hosts, and the 18S rRNA gene can be used to detect all associated eukaryotic pathogens, including Trypanosoma spp. Methods: Tsetse flies were collected from the Serengeti National Park (n = 48), Maswa Game Reserve (n = 42), and Tarangire National Park (n = 49) in Tanzania in 2012-13. Amplicon deep sequencing targeting mammal-specific 12S rRNA and 18S rRNA genes was performed to screen the blood-feeding sources of tsetse flies and eukaryotic parasites in tsetse flies, respectively. Results: 12S rRNA gene deep sequencing revealed that various mammals were blood-feeding sources of the tsetse flies, including humans, common warthogs, African buffalos, mice, giraffes, African elephants, waterbucks, and lions. Genes of humans were less frequently detected in Serengeti (P = 0.0024), whereas African buffaloes were detected more frequently as a blood-feeding source (P = 0.0010). 18S rRNA gene deep sequencing showed that six tsetse samples harbored the Trypanosoma gene, which was identified as Trypanosoma godfreyi and Trypanosoma simiae in subsequent ITS1 gene sequencing. Conclusions: Through amplicon deep sequencing targeting the 12S rRNA and 18S rRNA genes, various mammalian animals were identified as blood-meal sources, and two Trypanosoma species were detected in tsetse flies collected from the Maswa Game Reserve, Serengeti National Park, and Tarangire National Park in Tanzania. This study illustrates the patterns of parasitism of tsetse fly, wild animals targeted by the fly, and Trypanosoma spp. carried by the fly in Tanzania. It may provide essential data for formulating better strategies to control African trypanosomes.ope

Ampicillin treated German cockroach extract leads to reduced inflammation in human lung cells and a mouse model of Asthma

Cockroaches can cause allergic sensitization in humans via contact with their feces or frass. Antibiotics can affect concentration of major allergen and total bacteria production in German cockroaches (Blattella germanica). This study examined the ability of antibiot-ic-treated German cockroaches to induce allergic airway inflammation and the effect of antibiotics on their lipopolysaccharide and Bla g1, 2, and 5 expression levels. Specifical-ly, we measured the ability of German cockroach extract (with or without prior antibiotic exposure) to induce allergic inflammation in human bronchial epithelial cells and a mouse model of asthma. Bacterial 16S rRNA and lipopolysaccharide levels were lower in ampi-cillin-treated cockroaches than in the control group. The Bla g1, Bla g2, and Bla g5 expression in ampicillin-treated cockroaches decreased at both the protein and RNA lev-els. In human bronchial epithelial cell lines BEAS-2B exposed to the ampicillin-treated extract, expression levels of interleukin-6 and interleukin-8 were lower than that in the control group. The total cell count and eosinophil count in bronchoalveolar lavage fluid was also lower in mice exposed to the ampicillin-treated extract than in those exposed to normal cockroach extract. Mouse lung histopathology showed reduced immune cell infiltration and mucus production in the ampicillin group. Our results showed that ampi-cillin treatment reduced the symbiont bacterial population and major allergen levels in German cockroaches, leading to reduced airway inflammation in mice. These results can facilitate the preparation of protein extracts for immunotherapy or diagnostics applications. © 2023 The Korean Society for Parasitology and Tropical Medicine.ope

Production of Dermatophagoides farinae Having Low Bacterial Content Using Ampicillin

Background: Symbiotic bacteria in house dust mites pose a risk of immunological side effects in the clinical use of immunotherapeutic agents. In this study, we investigated the duration for which the bacterial concentration in Dermatophagoides farinae could be kept low with antibiotic treatment, and whether the allergenic properties of the mite changed under ampicillin treatment. Methods: D. farinae was cultivated in the presence of ampicillin powder in an autoclaved medium for 6 weeks. After subsequent subcultures without ampicillin, the mites were harvested, and the extract was prepared. The amounts of bacteria, lipopolysaccharides (LPS), and two major allergens (Der f 1 and Der f 2) were measured. Human bronchial epithelial cells and mice were treated with the D. farinae extract to assess the allergic airway inflammation. Results: The number of bacteria and level of LPS were reduced by 150-fold and 33-fold, respectively, at least 18 weeks after ampicillin treatment. The concentration of Der f 1 and Der f 2 remained unchanged by ampicillin treatment. The secretion of interleukin (IL)-6 and IL-8 from the human airway epithelial cells decreased when treated with the extract of ampicillin-treated D. farinae compared with that of ampicillin-untreated D. farinae. A mouse asthma model was developed using ampicillin-treated D. farinae. We observed that the level of lung function, airway inflammation, and serum-specific immunoglobulin were not different for the mouse asthma model developed using ampicillin-treated D. farinae than the model developed using ampicillin-untreated D. farinae. Conclusions: We showed that bacterial content in D. farinae was reduced by ampicillin treatment, which was sufficient to induce allergic sensitization and an immune response. This method will be used to develop more controlled allergy immunotherapeutic agents. Copyright © 2023 Ju Yeong Kim et al.ope

Metabarcoding of bacteria and parasites in the gut of Apodemus agrarius

Background: The striped field mouse Apodemus agrarius is a wild rodent commonly found in fields in Korea. It is a known carrier of various pathogens. Amplicon-based next-generation sequencing (NGS) targeting the 16S ribosomal RNA (rRNA) gene is the most common technique used to analyze the bacterial microbiome. Although many bacterial microbiome analyses have been attempted using feces of wild animals, only a few studies have used NGS to screen for parasites. This study aimed to rapidly detect bacterial, fungal and parasitic pathogens in the guts of A. agrarius using NGS-based metabarcoding analysis. Methods: We conducted 18S/16S rDNA-targeted high-throughput sequencing on cecal samples collected from A. agrarius (n = 48) trapped in May and October 2017. Taxa of protozoa, fungi, helminths and bacteria in the cecal content were then identified. Results: Among the protozoa identified, the most prevalent was Tritrichomonas sp., found in all of the cecal samples, followed by Monocercomonas sp. (95.8% prevalence; in 46/48 samples) and Giardia sp. (75% prevalence; in 36/48 samples). For helminths, Heligmosomoides sp. was the most common, found in 85.4% (41/48) of samples, followed by Hymenolepis sp. (10.4%; 5/48) and Syphacia sp. (25%; 12/48). The 16S rRNA gene analysis showed that the microbial composition of the cecal samples changed by season (P = 0.005), with the linear discriminant analysis effect size showing that in the spring Escherichia coli and Lactobacillus murinus were more abundant and Helicobacter rodentium was less abundant. Helicobacter japonicus was more abundant and Prevotella_uc was less abundant in males. The microbial composition changed based on the Heligmosomoides sp. infection status (P = 0.019); specifically, Lactobacillus gasseri and Lactobacillus intestinalis were more abundant in the Heligmosomoides sp.-positive group than in the Heligmosomoides sp.-negative group. Conclusions: This study demonstrated that bacterial abundance changed based on the season and specific parasitic infection status of the trapped mice. These results highlight the advantages of NGS technology in monitoring zoonotic disease reservoirs.ope

그레이브즈 병 환자로부터 얻은 갑상선 조직에서의 산화질소합성효소 발현 및 지질 과산화 효과에 대한 연구

학위논문(석사)--서울대학교 대학원 :의학과 외과학전공,2005.Maste

과학문화사업 추진과정에서의 참여 주체간 정책 네트워크 연구 : 대학민국과학축전을 중심으로

학위논문(석사) --서울대학교 대학원 :행정학과(정책학전공),2008. 8.Maste