초기 발달단계에서 닭 배아의 다능성 획득에 관한 연구

학위논문 (석사)-- 서울대학교 대학원 : 농생명공학부 바이오모듈레이션전공, 2016. 2. 한재용.Pluripotency refers the ability that can differentiate into any of the three germ layersendoderm (gastrointestianl tract and lung), mesoderm (muscle, blood and bone) and ectoderm (nervous system and epidermal tissues). In mammals, embryogenesis is accompanied with a gradually loss of developmental capacity from a zygote which has totipotency. The zygote take series of cleavage to form cluster of cells for further development. The cluster of cells differentiate into ICM which has pluripotency and will makes body proper and trophectoderm which will differentiate into extraembryonic lineage cells. In vivo, pluripotency is gradually acquired from zygote through ZGA and pluripotent gene network. Embryonic pluripotency in the mouse is established and maintained by a gene-regulatory network under the control of a core set of transcription factors that include octamer-binding protein 4 (Oct4official name POU domain, class 5, transcription factor 1, Pou5f1), sex-determining region Y (SRY)-box containing gene 2 (Sox2), and homeobox protein Nanog. Notwithstanding usage in development biology, the studies for pluripotency in avian embryos is still remains largely unknown. Thus, to compare and analyze the acquisition of pluripotency between mammals and aves, we select chicken as a model of aves. We studied early development of intrauterine period of chick blastoderm. We described the general development of chick embryo. To investigate the novel phenomenon of chick development, firstly, we hypothesized that the gravity is one of the reason for shedding mechanism. We conducted ex vivo culture and the results indicate that gravity has no or little impact on the shedding phenomenon of chick blastoderm. Secondly, we conducted TUNEL assay with EGK.VIII blastoderms to detect programmed cell death (apopotosis). But, we cannot detect any TUNEL positive signals in shedding cells. Taken together, cell shedding, the novel mechanism of chick blastoderm during area pellucida formation, is not a passive moving of cells which is occurred by gravity or apoptosis. Next, we investigated the similarities of amino acid sequences of core pluripotent genes cPOUV and cNanog. As results, DNA binding domains of cPOUV and cNanog are highly conserved among the species, but the full length similarities of amino acid are low. Then, we focused on Nanog homeodomain of mouse and chicken were analyzed using PHYRE2. The results indicate that Nanog homeodomain of mouse and chicken have similar secondary structure and DNA binding sites. According to DNA binding domain similarity, we can assume that the function of chicken Nanog is similar to mouse. To investigate the expression of pluripotency related gene, we harvested chick blastoderms of intrauterine period by abdominal massage and classified the blastoderms according to Eyal-Giladi and Kochavs criteria. White Leghorn (WL) hens (54-56 weeks old) were used for the collection of intrauterine eggs. To collect oocytes, WL hens were sacrificed and the follicles were detached from the ovaries. Then, spatial and temporal expression patterns of pluripotent genes were observed during intrauterine stages of chick using PCR and in situ hybridization. RT- and Real time-PCR were conducted to investigate the expression of cPOUV, cSOX2, cNANOG and ENS-1. As results, EGK.X which is homologue of mouse blastocyst, has all the pluripotency related gene expression except cSOX2. However, expression dynamics is differ from those of mouse. Mouse Oct4 and Sox2 are maternally inherited and Nanog is upregulated by Oct4- Sox2 transcriptional complex in mouse embryo. But, in chicken, no cPOUV transcripts are found in the oocytes and cNANOG is expressed from the oocyte to EGK.X instead of cPOUV. cSOX2 is not exist until EGK.X in which pluripotency is fully acquired. Taken together, The lineage specific expression pattern of chick pluripotent genes are conserved. But their expression dynamics are differ from what occur in mammals and the underlying mechanisms could be different from mammals. Also, our results revealed that pluripotency seems to be related to cell shedding which is novel mechanism of chick early development. This work will serve as a foundation for the better elucidation of the mechanism of pluripotency formation and lineage segregation, as well as for the comparative information of the evo-devo among the species.CHAPTER 1. INTRODUCTION 1 CHAPTER 2. LITERATURE REVIEW 5 1. Early development of mammalian embryos 6 1.1. The first lineage specification of early embryos in mouse 6 1.2. The Second lineage specification of early embryos in mouse 9 2. Early development of avian embryos 10 2.1. Before the first cleavage of chick blastoderm 10 2.2. Cleavage period 11 2.3. Area pellucida formation period 13 3. Recent studies on pluripotency in vertebrate embryos 14 3.1. Mouse POUV 14 3.2. Mouse Nanog 15 3.3. Mouse Sox2 17 3.4. Pluripotency in other vertebrates 18 3.5. Pluripotency networks 21 4. Recent studies on pluripotency in avian embryos 24 4.1. Chicken embryonic stem cells 24 4.2. POUV 25 4.3. Nanog 27 4.4. Sox2 29 4.5. ENS-1 30 CHAPTER 3. STUDIES ON CELL SHEDDING DURING INTRAUTERINE PERIOD OF CHICK EMBRYOS 32 1. Introduction 33 2. Material and Methods 34 3. Results 38 4. Discussion 48 CHAPTER 4. ACQUISITION OF PLURIPOTENCY IN EARLY DEVELOPMENTAL STAGE OF CHICK BLASTODERM 51 1. Introduction 52 2. Materials and methods 55 3. Results 61 4. Discussion 89 REFERENCES 94Maste

A Study on the Function of Advocacy Coalition in Cases of Radioactive Waste Disposal Facility Location Selection

학위논문 (석사)-- 서울대학교 행정대학원 : 공기업정책학과, 2014. 8. 고길곤.방사성폐기물처분장은 대표적인 비선호시설이며 입지정책 추진 시 정부를 중심으로 하는 우호적 정책옹호연합이 형성되어 주도적으로 정책변화를 도모할 것으로 인식된다. 본 연구에서는 방사성폐기물처분장 입지정책에서 정책옹호연합을 구성하는 조직간의 신념, 자원, 전략의 결속력에 대한 사례분석을 통해 정책추진 과정에서 정책옹호연합의 순기능과 역기능을 확인하였다. 연구의 분석틀로써 Sabatier(1998)에 의해 제안된 정책옹호연합모형을 정책하위체제 구성 변수 중심으로 수정하여 사용하였고 중저준위 방사성폐기물처분장 입지 결정까지의 정책 변화를 대상으로 분석하였다. 연구의 결과 방사성폐기물처분장 정책과 관련하여 갈등 관리의 주체는 정부로 인식되고 지자체, 한국수력원자력, 방사성폐기물 관리공단, 원자력연구소, 원자력안전기술원, 원자력문화재단 등은 강한 정책옹호집단으로 비쳐지고 있다. 이들은 강한 우호적 정책옹호연합을 구성할 것으로 인식되지만 실제 갈등의 많은 요인은 조직들의 약한 신념체계, 부조화 및 역할 모호성 등에서 발생하였다. 우호적 정책옹호연합의 순기능으로 연합의 결속 강화, 지속성 확보, 풍부한 자원의 활용, 정책 추진 시기의 결정권 및 전략적 자원 활용 등을 기대할 수 있으나, 실제 정책 추진과정에서는 조직별 신념의 다양성 및 이질성에서 기인하는 상이한 목표 추구, 무임승차 조직의 발생, 자원의 낭비, 정보의 왜곡, 정책 신뢰성 저하 등의 역기능이 확인되었다. 결론적으로 방사성폐기물처분장 입지정책 추진 과정에서 정부 주도 정책옹호연합은 연합적 순기능을 기대하고 있으나 신념의 공유, 자원의 공유, 전략의 공유 측면에서 역기능을 드러내며 갈등을 효과적으로 관리하지 못하였다. 따라서 향후 고준위 방사성폐기물처분장을 비롯한 비선호시설 입지정책에서 우호적 정책옹호연합 조직의 구성과 역할 설정이 정책 성공의 주요 요소임을 제시하였다. 단일사례를 토대로 연구가 진행되어 연구 결과의 일반화가 어렵다는 점, 효과적인 정책옹호연합 구성에 대한 구체적 방법론 제시로 연계되지 못한 점은 연구의 한계이며 이에 대해서는 향후 계속적인 연구가 요구된다.제 1 장 서론 제 1 절 연구배경 및 목적 제 2 절 연구범위 및 방법 제 2 장 이론적 배경 제 1 절 정책옹호연합모형의 검토 1. 정책옹호연합모형의 개념과 특징 2. 정책옹호연합모형의 발전과정 3. 정책옹호연합모형의 구조와 주요 변수 4. ACF를 적용한 정책변화 연구 제 2 절 방폐장 입지선정 정책에 관한 선행연구 검토 1. 방폐장 입지 선정 정책에 관한 선행 연구 2. 선행연구의 한계 3. 연구분석틀 설정 제 3 장 방폐장 입지정책 추진과정 분석 제 1 절 정책의 개요 1. 원자력발전과 방사성폐기물 2. 방사성폐기물 현황 3. 방사성폐기물처분장 입지정책의 요약 제 2 절 방사성폐기물처분장 입지정책 추진과정 1. 방사성폐기물관리사업 계획 수립 2. 부지선정 과정 3. 중·저준위방폐장 부지선정 제 3 절 ACF를 활용한 분석 1. 외부변수 2. 정책옹호연합의 형성과 신념체계 3. 정책중개자 4. 정책학습 5. 정책산출 및 정책영향과 변동 제 4 절 정책옹호연합의 순기능과 역기능 1. 신념 공유 : 이질성 2. 자원 공유 : 이론적‧현실적 적실성 3. 전략 공유 : 조직 특성의 다양성 제 4 장 결론 및 연구의 한계 참고문헌Maste

사용자 제어가 가능한 적응형 화일 캐슁

학위논문(박사) - 한국과학기술원 : 전산학과, 1998.2, [ v, 108 p. ]As disk performance continues to lag behind microprocessors and memory systems, the file system caching has a growing importance in many applications. An effective file system caching can reduce disk accesses significantly. This paper proposes an adaptive and flexible buffer cache management scheme which can handle workloads with various file access characteristics and can exploit applications`` knowledge about their access pattern to improve the file system performance. Most traditional file systems employ a global LRU policy as the buffer replacement policy. The problem with the global LRU policy is that a single global policy, LRU, is applied to all applications without exception and it may not perform well outside the “typical” computing environment. Our solution is the split-level buffer cache management where responsibility of the buffer cache management is split between the kernel and the applications. The kernel provides user applications with a default replacement policy flexible enough to cope with various file access characteristics. Applications can change and customize kernel``s behavior to their needs. For the kernel, we propose a new replacement policy called LRU-RS. Under LRU-RS, the buffer cache is managed in terms of files rather than blocks so as to enforce a different replacement policy for each cached file according to its access pattern. In order to prevent the buffer cache from being wasted by a very long sequential run, a technique of recycling buffers is introduced. In addition, an adaptive recycling technique is also employed to distinguish between frequently-accessed and infrequently-accessed large files with a small amount of the buffer cache. For application-specific management, we propose a set of flexible interfaces through which applications can exert fine control over the buffer replacement management. System call interfaces are employed in order to minimize interactions between the kernel and applications but not to add to t...한국과학기술원 : 전산학과

Architecture-aware Automatic Computation Offload for Native Applications

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CloudSwap: A Cloud-Assisted Swap Mechanism for Mobile Devices

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화이트레그혼 대리난각 배양에 의한 오계 배아 발생

The avian embryos have been used as a good model to study embryonic development. Due to its uniquedevelopment in the eggshell, avian embryos can be cultured and hatch in the surrogate eggshell system. In this study, weexamined the viability, normal development and hatchability of Korean Oge (KO) chicken embryos in White Leghorn (WL)surrogate eggshells. Donor KO embryos at 3-day and 4-day-old were transferred into recipient WL eggshells, incubated forfurther 18 days at 37.5℃ with 70% of humidity until hatching. The viability of 3-day-old KO embryos at 7, 14 and 21 dayin surrogate eggshell were 70.0%, 43.8% and 23.1%, respectively. In contrast, the viability of 4-day-old KO embryos at 7,14 and 21 day in surrogate eggshells were 87.1%, 55.6% and 36.0%, respectively. The hatchability of KO embryos transferredinto surrogate eggshells at 3-day-old was 23.1%, whereas embryos transferred at 4-day-old was 36.0%. Furthermore, thedevelopment of all viable embryos from 3-day group and 4-day group were normal. Our results suggested that culture of KOembryos in WL surrogate eggshells is highly possible, and transfer of donor embryos at 4-day-old may yield higher percentageof hatchability. This study may provide potential knowledge for the conservation of wild and endangered birds throughsurrogate system.N