Fabrication of Fluorescent Hybrid Nanoparticles and Their Specific Ion and Molecule Detection Applications

학위논문 (박사)-- 서울대학교 대학원 : 화학생물공학부, 2016. 8. 장정식.Various nanoprobe systems are being developed to explore their potential in biomedical fields, with many applications to the diagnosis or monitoring of various diseases. There are many advantages of nano-size probes for the application in biomedical field. First, the scale of cell and tissue structures is meaningful. Since most nanoprobes are about 10—500nm which are generally over 100 fold smaller than cells. Second, the building blocks of nanoprobes like proteins, carbohydrates, nucleic acids, synthetic polymers or small inorganic particles are generally smaller than about several scores of nanometers. Third, nanoprobes have potential for wide application because they can easily contain useful molecules such as imaging agents, active targeting moieties, or drugs by simple loading or conjugation. Consequently, it is still challenging to produce fluorescent hybrid nanoparticles for detecting and imaging target analytes in living systems. This dissertation describes the three different ways in the synthetic methodology of fluorescent hybrid nanoparticles. First, PAN nanomaterials as novel bioimaging agents without additional fluorophores were developed by ultrasound induced emulsion polymerization, and it could be applied for the fluorescence sensors of copper ion and cell imaging. Second, a dual emission Au-PAN NPs sensor was prepared for sensitive detection of mercury ions in aqueous solution. The Au-PAN nanoparticles showed significant intensity change by addtion of mercury ions and higher binding affinity toward mercury ion than other metal ions. Lastly, a novel fluorescent Au-GQDs nanoparticle was synthesized for use as a probe that can selectively detect Cys in living cells. The dual emission fluorescence peak ratio changed when the Au-GQDs nanoparticles reacted with Cys. This fluorescence behavior was highly specific for Cys. Most importantly, these novel approaches can be used as an alternative tool for specific ions and molecule detection in environmental condition, and may offer an opportunity for the further investigation of industrial applications, and might be expanded to allow the fluorescence sensor applications of hybrid nanoparticles in a wide range of areas.1. INTRODUCTION 1 1.1. Background 1 1.1.1. Nanoprobe 1 1.1.2. Materials of Nanoprobe 4 1.1.3. Fluorescent Nanoprobe for Bioimaging applications 20 1.2. Objectives and Outlines 28 1.2.1. Objectives 28 1.2.2. Outlines 28 2. EXPERIMENTAL DETAILS 32 2.1. Amidine/Schiff Base Dual-Modified PAN Nanoparticles and Their Application 32 2.1.1. Fabrication of Amidine/Schiff Base Dual-Modified PAN Nanoparticles 32 2.1.2. Application for Intracellular Copper Ion Detection 35 2.2. Au-decorated PAN Nanoparticles with Dual-Emission and Their Application 37 2.2.1. Fabrication of Au-decorated PAN Nanoparticles with Dual-Emission 37 2.2.2. Application for Mercury Ion Detection 40 2.3. Au-decorated Graphene Quantum Dots with Dual-Emission and Their Application 41 2.3.1. Fabrication of Au-decorated Graphene Quantum Dots with Dual-Emission 41 2.3.2. Application for Intracellular Cysteine Detection 44 3. RESULTS AND DISCUSSION 46 3.1. Amidine/Schiff Base Dual-Modified PAN Nanoparticles and Their Application 46 3.1.1. Fabrication of Amidine/Schiff Base Dual-Modified PAN Nanoparticles 46 3.1.2. Application for Intracellular Copper Ion Detection 63 3.2. Au-decorated PAN Nanoparticles with Dual-Emission and Their Application 68 3.2.1. Fabrication of Au-decorated PAN Nanoparticles with Dual-Emission 68 3.2.2. Application for Mercury Ion Detection 77 3.3. Au-decorated Graphene Quantum Dots with Dual-Emission and Their Application 84 3.3.1. Fabrication of Au-decorated Graphene Quantum Dots with Dual-Emission 84 3.3.2. Application for Intracellular Cysteine Detection 97 4. CONCLUSIONS 101 REFERENCES 104 국문 초록 110Docto

추력조절이 가능한 액체중심 동축형 스월 분사기의 분무특성에 관한 실험적 연구

학위논문 (석사)-- 서울대학교 대학원 : 기계항공공학부, 2014. 2. 윤영빈.In liquid rocket engine, the study on throttling have been conducted since 1930s. The throttleable rocket engine enables the operational possibilities, for example docking of spacecraft, maneuvering in certain orbit and landing on a surface of planet, attitude control, entrance to atmosphereless of planet and etc. To achieve throttling in liquid rocket engine, methods are classified by target variable, such as high pressure drop, change in discharge coefficient, various density, and change in nozzle area Meanwhile, as rocket engine employed bi-propellant instead of mono-propellant, mixing efficiency became a major criteria in engine design stage. In order to mix fuel and propellant, impinging type injector, coaxial type injector, etc. were developed. For a coaxial type injector, the injector, such as shear coaxial injector and swirl coaxial injector, could be classified by injection type. And liquid centered injector and gas centered could be classified by injection position. To investigate the characteristics of injector, lots of method have been studied. In liquid rocket engine, rocket engine do not employed a single injector, but tens or hundreds of injector are installed in injector plate. So, interference between spray from injector could be occurred. To avoid the interference, prediction of spray angle is important variable in characteristics of liquid rocket injector. Also the diameter of droplets is considered in design stage since it could influence on combustion instability. In this study, dual manifold, one of controlling discharge coefficient, was used to control the thrust in liquid phase. And liquid centered coaxial injector was employed to mix liquid and gas simulant. To investigate variation of mixture ratio F/O ratio increased 0, 1/10, 1/8, and 1/6 in the experience. In order to comparative study between dual manifold injector and single manifold injector, the spray angle, mass flow rate, diameters of droplets, and mean diameter of droplets which are representative characteristics in spray, were investigated.Chapter 1 INTRODUCTION 1 Chapter 2 APPARATUS AND EXPERIMENTAL METHOD 5 2.1 Experimental Appraatus 5 2.2 Indirect Photograghy 7 2.3 Image Processing Method 8 2.4 Experimental Condition 11 Chapter 3 RESULT AND DISCUSSION 13 3.1 Mass Flow Rate 13 3.2 Spray Pattern 16 3.3 SMD Distribution 23 Chapter 4 CONCLUSION 32 Bibliography 34 Abstract in Korean 36Maste

신입생을 위한 캠퍼스 적응, 지도 프로그램 - 명예교수 멘토링

서울대학교 명예교수협의회는 명예교수들이 지닌 지적 재산을 사회에 환원하기 위한 활동의 일환으로 일반 대학에서 미처 포괄하지 못하는 학제 간의 다양한 틈새 학문 영역을 개발하고, 빠르게는 40대로부터 시작되는 다양한 연령층의 퇴직자들이 여생을 위한 새로운 직업에 도전할 수 있도록 도움을 주기 위하여제3기 인생대학(정년 후 새로운 취업 길을 모색하는 사람들을 대상으로 한 교육)의 프로그램을 개발하거나, 평생교육 프로그램에 참여하는 일, 그리고 오늘의 대학 현실처럼 과중한 연구와 교육의 업무로 인하여 현직 교수들의 손이 미치지 못하는 소외된 학생들도 대학생활에 성공적으로 적응할 수 있도록 도움을 주는 개별적인 신입생 멘토링 프로그램 등에 참여하고 있다

Regulation of CD4+CD8–CD25+ and CD4+CD8+CD25+ T cells by gut microbiota in chicken

학위논문 (박사)-- 서울대학교 대학원 : 농생명공학부, 2017. 2. 윤철희.Gut microbiota in chicken has long been studied and considered for mostly growth performance point of view. And therefore, immunological studies regarding gut homeostasis in chicken have been insufficiently achieved. Regulatory T cells (Tregs) are a notable subtype of CD4+ T cells playing an important role to maintain gut homeostasis in humans and animals. Intestinal Tregs are induced by gut microbiota, such as, Clostridium spp. cluster IV and XIVa strains, altered Schaedler flora (ASF), or Bacteroides fragilis in mice. Although it has been suggested that CD4+CD25+ T cells act as Tregs, there are no such studies showing the relationship between gut microbiota and Tregs in chickens. The first, I established the model for ABX-treated chickens by the administration of various concentrations of antibiotic cocktail consisting of ampicillin, gentamycin, neomycin, metronidazole, and vancomycin in water. Cecal contents from chickens treated with antibiotic cocktail consisting of 100 g/ml of ampicillin, gentamycin, neomycin and metronidazole, and 50 g/ml of vancomycin for 7 days eliminated colony forming unit (CFU) over 99%. These chickens treated by certain concentration of antibiotics cocktail (ABX) were referred as ABX-treated chickens. There were no changes on physiological traits, for example, weight of body and immune organs (spleen, bursa and liver), length of intestine (duodenum, jejunum, ileum and large intestine) and the concentration of glucocorticoid in the serum. Furthermore, the population and MHC class II expression on B cells and macrophages in the cecal tonsils and spleen were not changed. I concluded that physiological traits, B cells and macrophages were not changed in ABX-treated chickens. The second, I examined whether subtype of CD4+ T cells was changed in ABX-treated chickens. In cecal tonsil, CD4+CD8–CD25+ and CD4+CD8+CD25+ T cells were significantly decreased in ABX-treated chickens, however these cells in the spleen were not changed. The expression of IL-10 and IFN-g was significantly decreased in CD4+CD8–CD25+ T cells from cecal tonsils of ABX-treated chickens. It was noting that CD4+CD8–CD25+ and CD4+CD8+CD25+ T cells from ABX-treated chickens did not suppress the proliferation of CD4+CD25– T cells. The reduction of CD4+CD8–CD25+ and CD4+CD8+CD25+ T cells in cecal tonsils from ABX-treated chickens expressed high level of CD5hi. Interestingly, the percentage of thymic CD4+CD8+CD25+ T cells was not changed in ABX-treated chickens. Conclusively, the population and suppressive function of peripheral CD4+CD8–CD25+ and CD4+CD8+CD25+ T cells decreased in ABX-treated chickens. The third, I examined what factors affected the population of CD4+CD8–CD25+ and CD4+CD8+CD25+ T cells. ABX-treated chickens co-housed with wild type chickens recovered the number of gut microbiota, and the proportion of CD4+CD8–CD25+ or CD4+CD8+CD25+ T cells in cecal tonsils to similar levels as those of wild type chickens. The results further showed that Gram-positive bacteria appeared to be responsible for the changes of CD4+CD8–CD25+ or CD4+CD8+CD25+ T cells in cecal tonsils. Feeding acetate, one of the short chain fatty acids, in ABX-treated chickens recovered CD4+CD8–CD25+ T cells and CD4+CD8+CD25+ T cells in cecal tonsils. Both butyrate and propionate did not show the effect to recover these cells. Interestingly, GPR43 mRNA level was highly expressed in CD4+CD8–CD25+ T cells. Conclusively, my study demonstrated that gut microbiota can regulate the population and suppressive function of CD4+CD8–CD25+ or CD4+CD8+CD25+ T cells, and acetate can induce CD4+CD8–CD25+ T cells in cecal tonsils via GPR43.I. Review of Literature 1 1. Gut homeostasis 1 1.1. Regulatory T cells 1 1.2. T helper 17 cells 3 1.3. Immunoglobulin A 4 1.4. Innate lymphoid cells 6 2. Gut microbiota in chicken 7 2.1. Intestine 7 2.2. Establishment of gut microbiota 8 2.3. Gut microbiota on growth performance 9 2.4. Effects of gut microbiota on immunological aspect 10 II. Introduction 13 III. Materials and Methods 16 1) Experimental animal and ABX treatment 16 2) Measurement of colony forming unit 17 3) Examination of physiological changes in ABX-treated chickens 17 4) Flow cytometric analysis for immune cells 18 5) Measurement of mRNA level using RT-qPCR 19 6) Changes on the subtype of CD4+ T cells treated with antibiotics in vitro 21 7) T cell suppression assay 21 8) Co-housing experiment 22 9) The elimination of Gram positive and negative bacteria 23 10) Administration of short chain fatty acids 23 11) Statistical Analysis 23 IV. Results 25 1) Elimination of gut microbiota in chicken 25 2) Verification of physiological alteration in ABX-treated chickens 28 3) Change of B cells and macrophages in ABX-treated chickens 30 4) Change of CD4+ T cells in ABX-treated chickens 32 5) Change of IL-10 and IFN-g from subtype of CD4+ T cells in ABX-treated chickens 36 6) Direct effect of antibiotics on the change of CD4+CD8–CD25+ and CD4+CD8+CD25+ T cells 38 7) Changes of CD4+CD8–CD25+ and CD4+CD8+CD25+ T cells in periphery of ABX-treated chickens 40 8) Suppressive function of CD4+CD8–CD25+ and CD4+CD8+CD25+ T cells in ABX-treated chickens 43 9) Changes of CD4+CD8–CD25+ and CD4+CD8+CD25+ T cells in ABX-treated chickens after co-housing with control chickens 45 10) Effect of Gram-positive or negative bacteria on the population changes of CD4+CD8–CD25+ and CD4+CD8+CD25+ T cells 47 11) Effect of SCFAs on CD4+CD8–CD25+ and CD4+CD8+CD25+ T cells 49 V. Discussion 51 VI. Literature Cited 60 VII. Summary in Korean 78Docto

Detection of an anthrax biomarker by screen-printed fluorescent sensors

학위논문 (석사)-- 서울대학교 대학원 : 화학생물공학부(에너지환경 화학융합기술전공), 2013. 8. 장정식.스크린 프린팅 기법과 두 개의 란탄족 이온을 이용해 제조된 형광 센서의 탄저균 검출을 대표적인 탄저균 바이오마커인 디피콜린산을 이용해 알아보았다. 두 종류의 서로 다른 란탄족 이온(유로피움 그리고 터비움)을 에틸렌디아민 사초산과 수용액 상태에서 결합시키고 폴리비닐알코올을 넣어 점도를 높인 후 폴리에터술폰 필름 위로 스크린 프린팅을 수행하였다. 란탄족 이온과 에틸렌디아민 사초산과의 결합은 핵자기공명 분광법과 푸리에 변환 적외분광법을 이용해 관찰했다. 란탄족 이온의 최적 농도 측정과 제조된 형광 센서의 디피콜린산 비율 측정은 자외선 등과 형광분석기를 통해 체계적으로 조사되었다. 유로피움을 이용한 형광 센서와 터비움을 이용한 형광 센서 모두 놀라운 검출 한계 (각각 0.5 나노몰, 0.1 나노몰)를 보여주었으며 터비움을 이용한 형광 센서가 보다 높은 감도를 보여주었다. 이는 작은 에너지 갭과 디피콜린산 삼중 상태와 들뜬 상태의 터비움 사이의 강결합에 의한 것이라 사료된다. 추가적으로 유로피움과 터비움을 사용한 두 형광 센서의 다양한 방향족 리간드의 검출 능력을 비교해보았을 때 디피콜린산에 대해서 뛰어난 선택성(각각 135배, 200배)을 나타내었다. 이러한 결과들은 스크린 프린팅 방법과 두 종류의 란탄족 이온이 함께 탄저균 검출에 이용되었을 때 높은 검출 감도와 선택적 검출에 대한 중요한 정보들을 제공하게 될 것으로 판단된다.Chapter 1 Introduction 1 1.1 Anthrax disease 1 1.2 Lanthanide luminescence 4 1.3 Anthrax biomarker detection via lanthanide luminescence 11 1.4 Lanthanide-macrocycle complex 14 1.5 Screen-printing method 15 Chapter 2 Experimental Details 18 2.1 Materials 18 2.2 Preparation of ink pastes for screen-printing 18 2.3 Lanthanide-based anthrax detectors via screen-printing 19 2.4 Quantum yield 19 2.5 DPA detection 20 Chapter 3 Results and Discussion 22 3.1 Fabrication of screen-printed anthrax biomarker detectors 22 3.2 Characterization of anthrax biomarker detectors 31 3.3 Optimal concentration of lanthanide metals 35 3.4 Sensitivity of screen-printed anthrax biomarker detectors 38 3.5 Selectivity of screen-printed anthrax biomarker detectors 44 Chapter 4 Conclusions 50 References 51 국문초록 53Maste

작가와 독자의 대화로서 Vanity Fair : 19세기 소설 독서의 한 의미와 관련하여

현대소설에 비하여 19세기 소설을 읽는 즐거움의 하나는 우리가 일종의 편안함을 가지고 작품을 대할 수 있다는 데에 있다. 물론 이때 편안하다는 말은 다분히 유보적인 것이다. 왜냐하면 현대소설에 익숙한 독자는 대체로 길이가 걸고 구성이 느슨하며 틈나는 대로 작가의 목소리가 튀어나오는 19세기 소설을 읽을 때 오히려 부담스럽고 지리하며 부자유스럽게 느끼기가 쉽기 때문이다. 사실 Henry James 이후 전개된 현대소설론에 있어 작가의 개업을 가능한 한 억제하고 등장인물들로 하여금 스스로를 보여주도록 하는 것이 소설미학상의 장점으로 역설되어온 바, 독자는 작가의 간섭으로부터 벗어나 자신의 강수성과 상상력에 의해 자유로이 작품을 읽을 수 있게 되었다. 그러나 독자의 이러한 자유로움의 권리획득이 반드시 소설읽기의 편안함을 가져온 것은 아니라고 할 수 있다. 자유로와진다는 것은 그것에 수반되는 의무의 요건을 갖추는 한에서만 가능하기 때문이다. 작가는 독자에게 자유로움을 허용하는 대신 작품뒤에 숨어들어가 한충 정교하고 섬세한 언어와 구성으로 복잡하고 세련된 삶의 모습을 짜놓고서, 독자에게 그것을 제대로 읽어내고 판단할 수 있는 감수성과 상상력의 날카로움과 긴장된 노력을 갖추도록 끊임없이 요구하는 것이다. 결국 독자의 자유로움이란 소설읽기의 상당한 어려움을 통과한 뒤에야 비로소 얻어낸 위안물에 다름아닌 것이다. 따라서 이른바 현대의 독자가 19세기 소설을 대할 때 갖는 불편함은 기실 어려운 훈련과정과 자격요건을 거쳐 겨우 획득한 자유로움의 권리를 행사할 수 없다는 낭패감에서 기인하는 것에 불과하다. 이것은 말하자자면 우리가 이와같이 이율배반적인 현대독자로서의 권리와 의무를 유보하는 순간 19세기 소설의 독서는 실로 편안해질 수 있다는 것을 의미한다. 그리고 이 때에 19세기 소설의 긴 분량과 느슨한 이야기 전개는 부담스러움과 답답함보다 느긋함과 여유가 되고 상존하는 작가의 목소리는 간섭자와 권위자의 것이 아니라 친밀한 동반자이자 자연스려운 대화자의 것이 되는 것이다

국가적인 지적 자산 축적을 위한 제언

과학 기술의 발달로 우리의 평균 수명이 날로 다르게 연장되고 있다는 것은 결코 새삼스러운 이야기가 아니다. 단순히 평균 수명만 늘어나는 것이 아니라 건강하게 살 수 있는 삶의 질도 높아져서, 오늘의 70대는 과거 우리 선친 세대가 환갑을 맞을 때보다 더 건강하고 활동적임을 모두가 인지하는 바다. 그럼에도 불구하고 우리 사회는 개인적인 능력이나 건강 여건은 불문에 부치고 정년이라는 획일적인 잣대로 공적 활동을 정지시키고 있으니, 이로 인한 국가적인 손실은 말할 수 없이 크게 되었다. 대학의 경우 그것은 고급 두뇌가 지닌 지적 자산을 사장시키는 일로 직결되고 있어, 이제는 한 번쯤 이 문제를 심각하게 논의해야 할 시점에 이르렀다고 생각한다. 우리나라 사회 전반이 이처럼 물리적인 연령으로 정년을 재단하고 있으니, 대학만을 예외로 하라고는 할 수 없을 것이다. 더욱이 대학은 만 65세라는 가장 늦은 나이까지 활동을 보장하고 있어. 더 이상 무엇을 요구한다는 것은 과욕이라고 말할 수도 있을 것이다. 그럼에도 불구하고 이와 같은 문제를 공론하고자 하는 것은 실버 세대가 급격하게 늘어난 오늘의 사회적인 여건을 외면할 수 없기 때문이다

자동차 헤드라이트용 고압 방전등 안정기 시스템의 모델링 및 제어기 설계

학위논문(석사)--서울대학교 대학원 :전기공학부,2000.Maste

Analysis and Design of an Electronic Ballast for MHD Lamps

학위논문(박사) --서울대학교 대학원 :전기. 컴퓨터공학부,2007.Docto