The correlation between lipid peroxidation and procine Embryo fragmentation

김민석 건국대학교 2006 국내석사

Implication of product fragmentation on the economic integration in East Asia

조해옥 Graduate School of International Studies, Korea Un 2014 국내석사

Production networks in East Asia have drawn attention since 1990’s. With the development of production networks, trade pattern in East Asia has experienced qualitative change from inter-industry trade to intra-industry trade. Production networks are basically based on product fragmentation which is characterized by breaking up the production processes into geographically separated locations. As production networks based on product fragmentation developed in East Asia, intra-regional trade in parts and components within the production networks has become important since product fragmentation necessarily induces trade in parts and components for one final goods. This paper proves that production networks based on the product fragmentation plays an important role for increasing trade among East Asian countries. To investigate the share of intra-regional trade in parts and components, trade in machinery sector is examined. From this research, findings indicate that production networks based on the product fragmentation in East Asia have a significant impact on the expansion of trade among East Asian countries from 1995 to 2012. With the findings, this paper attempts to explore implications of product fragmentation on the economic integration in East Asia. If product fragmentation significantly affects the regional trade outcome then it needs to be examined what East Asian countries pursue for elaborating production networks based on product fragmentation.

Elucidation of apoptotic DNA fragmentation mechanism via biochemical and structural study of Drep system : Drep system의 생화학, 분자 구조연구를 통한 apoptotic DNA fragmentation 조절 메커니즘 규명

박옥경 영남대학교 대학원 2012 국내석사

DNA fragmentation is common phenomenon for apoptotic cell death. DNA fragmentation factor, called DFF40 (CAD: mouse homologue), is a main nuclease for apoptotic DNA fragmentation. Nuclease activity of DFF40 is normally inhibited by DFF45 by tight interaction via CIDE domain without apoptotic stimuli. Once effector caspase is activated during apoptosis signaling, it cleave DFF45, allowing DFF40 to enter the nucleus and cleave chromosomal DNA. Unlike mammalian system, apoptotic DNA fragmentation in the fly might be controlled by four DFF-related proteins, known as Drep1, Drep2, Drep3 and Drep4. Although the function of Drep1 and Drep4 is well known as DFF45 and DFF40 homologues, respectively, the function of Drep2 and Drep3 is still unclear. DFF-related proteins contain a conserved CIDE domain of ~90 amino acid residues that is involved in protein-protein interaction. Here, we showed that Drep1 directly bind to Drep2 as well as Drep4 via CIDE domain. In addition, we found that the interaction of Drep2 and Drep4 to Drep1 was not competitive indicating that Drep2 and Drep4 bind different place of Drep1. And we found that full-length Drep2 exists as a highly oligomeric form mediated by CIDE domain oligomerization in solution unlike Drep3, which usually exists as a monomer in solution. We also found that Drep2 has nuclease activity, and that Drep2 nuclease activity was inhibited by Drep3 by a direct interaction. Based on our results, we conclude that the fly has a dual apoptotic DNA fragmentation system: a Drep1:Drep4 complex and a Drep2:Drep3 complex. Drep4 and Drep2 are nucleases and their activity is inhibited by Drep1 and Drep3, respectively. DNA fragmentation은 apoptotic 세포 죽음의 일반적인 현상이다. DFF40(CAD:mouse homologue)라 불리는 DNA fragmentation factor는 DNA fragmentation의 주요 핵산가수분해 효소 이다. DFF40의 핵산가수분해 활성은 일반적으로 apoptotic 자극이 없을 때, CIDE 도메인의 단단한 상호작용을 통해 DFF45에 의해 저해된다. Apoptosis 신호 중에 caspase가 활성화되면 DFF45를 분해하고, DFF40이 핵 안으로 들어가 염색체 DNA를 분해 한다. 포유류의 시스템과는 달리, 파리에서 apoptotic DNA fragmentation은 Drep1, Drep2, Drep3 그리고 Drep4로 알려진 네개의 DFF 관련 단백질에 의해 제어된다. Drep1과 Drep4의 기능은 각각 DFF45와 DFF40의 상동으로 잘 알려져 있지만, Drep2와 Drep3의 기능은 아직 분명하지 않다. DFF관련 단백질들은 단백질-단백질 간의 상호작용에 관여하는 ~90개의 아미노산을 포함하는 CIDE 도메인을 가진다. Drep1은 Drep4뿐만 아니라 Drep2와도 CIDE 도메인을 통해 직접적을 결합한다. 게다가 Drep2와 Drep4는 Drep1의 다른장소에 결합하며 경쟁적이지 않은 것으로 나타났다. 그리고 Drep2 전체 단백질은 용액에서 단량체로 존재하는 Drep3전체 단백질과 달리 CIDE 도메인 끼리의 origomerization으로 높은 oligomeric형태로 존재한다. 또한 Drep2의 핵산가수분해 활성과, 핵산가수분해 활성이 Drep3에 의해 저해되는 것을 밝혔다. 우리의 결과들을 바탕으로 파리는 Drep1:Drep2 복합체 그리고 Drep2:Drep3 복합체 두 가지의 apoptotic DNA fragmentation 시스템이 있다는 결론을 내렸다. Drep4와 Drep2의 핵산가수분해 활성은 각각 Drep1과 Drep3에 의해 저해된다.

TUNEL法과 DNA fragmentation法에 의한 흰쥐 腎臟細胞에서 아포토시스의 檢索 比較

지수일 建國大學校 農畜大學院 1998 국내석사

아포토시스는 염증반응의 동반없이 핵염색질의 분절로 나타나는 생리적인 세포사멸로 기존의 단순염색의 광학현미경적 관찰이나 TUNEL기법을 이용한 면역화학적 방법, 전기영동을 이용한 DNA fragmentation 관찰 등의 다양한 방법으로 확인할 수 있다. 본 연구에서는 아포토시스 관찰을 위한 방법들의 장단점을 비교하기 위하여 cyclosporine A를 처리한 흰쥐의 신장을 시간별로 적출하여 아포토시스의 형태 및 정도를 기존의 단순염색의 광학현미경적 관찰과 TUNEL기법을 이용한 면역화학적 방법, 전기영동을 이용한 DNA fragmentation 관찰을 시행하여 비교하였다. 이들의 결과는 다음과 같다. 1. 아포토시스체는 기존의 H-E 및 PAS 염색에 의한 광학현미경적 방법으로 관찰할 수 있었다. 그러나 쥐의 세뇨관 상피세포에서의 아포토시스체 정량분석을 시행한 결과 cyclosporine A를 투여한 경우와 정상 대조군에서 의의있는 차이를 나타내지 못하였다. 2. Cyclosporine A를 투여한 쥐의 신선한 신장조직에서 아포토시스는 전기영동을 이용한 DNA fragmentation 관찰법에 의해 관찰이 용이하였으나 정량분석에 어려움이 있었고 아포토시스 세포의 조직내 위치확인이 불가능하였다. 3. TUNEL기법을 이용한 면역화학적 방법으로 아포토시스를 관찰한 결과 아포토시스 세포는 TUNEL기법을 이용한 면역화학적 반응에 강하게 반응하였다. 이러한 TUNEL기법을 이용한 면역화학적 방법은 아포토시스를 일으킨 세포뿐만 아니라 아포토시스 과정에 있는 세포의 형태학적 관찰 및 정량분석이 용이하였으며, 조직내에서의 아포토시스 세포의 위치 확인이 가능하였다. 4. Cyclosporine A를 투여한 쥐의 신장조직에서 PCNA염색으로 확인한 세포증식능은 아포토시스와 유의한 연관성을 보였으며, 이는 아포토시스 유발 초기에는 증가되고, 시간이 경과함에 따라 감소되었다. 이상의 결과에서 아포토시스를 관찰하기 위한 방법에서 TUNEL기법을 이용한 면역화학적 방법은 아포토시스의 형태학적 관찰이나 정량분석 및 위치확인에 있어 기존의 H-E 및 PAS 염색에 의한 광학현미경적 방법이나, DNA fragmentation법 보다 우수함을 알 수 있다. 더불어 cyclosporine A를 투여한 쥐의 신장조직에서 PCNA염색으로 확인한 세포증식능은 아포토시스와 유의한 연관성이 있음을 알 수 있다. Apoptosis is a highly regulated process of cell death characterized by nuclear fragmentation without accompanying inflammatory reaction. It can be detected by specific and selective techniques, such as conventional light microscopy, DNA fragmentation analysis by gel electrophoresis (DNA laddering), and histochemical in situ nick-end labeling (TUNEL) method. To compare each technique for the detection of apoptosis with respect to the qualitative and quantitative analysis, the kidneys of the Sprague Dawley rat treated with cyclosporine A (n=30) were sacrificed according to time and were examined by light microscopy, TUNEL method and DNA laddering. The results were as follows. 1 . Apoptotic bodies of the rat kidney treated with cyclosporine A were occasionally demonstrated by conventional hematoxylin-eosin (H-E) and periodic acid schiff (PAS) stains, however these methods could not discriminate the significant difference in the detection of apoptosis of the renal tubular epithelial cells between the cyclosporine A treated rats and the control rats. 2. Apoptosis could be recognized as the characteristic DNA ladder pattern on agarose gel electrophoresis in the fresh tissues of the rat kidney after the treatment of cyclosporine A, but DNA laddering has limited value in the quantitative analysis and the verification of the site of apoptosis and needed the fresh tissues. 3. Labeling was most intense in apoptotic nuclei on TUNEL method. This method can be adapted for paraffin tissue section. Moreover one can simultaneously assess the quantitative and qualitative analysis of apoptotic cells and cells committed to apoptosis and the localization of staining, making this an incredibly powerful tool for apoptosis detection. 4. Cellular proliferation index demonstrated by PCNA staining correlated with apoptosis in the rat kidney after the treatment of cyclosporine A, which increased in early period and decreased later. With these results, TUNEL method is superior to conventional light microscopic method such as H-E and PAS staining or DNA fragmentation method for the detection of apoptosis. In addition, these findings suggest that the frequency of apoptosis is significantly correlated with cellular proliferation.

Impacts of anthropogenic activities on forest fires and fragmentation in the Korean Peninsula

박용 서울대학교 대학원 2024 국내박사

This research delves into the profound anthropogenic influences on forest ecosystems, specifically addressing the critical issues of forest fragmentation and fires on the Korean Peninsula. Recognizing the imperative need for a nuanced understanding of these impacts, the study unfolds a comprehensive exploration. A pivotal aspect underscored in this paper is the significance of customized forest management strategies, accounting for regional idiosyncrasies such as topography and climate. The impending threats emanating from forest fragmentation and anthropogenic forest fires to biodiversity and the consequential ecological havoc are spotlighted. The research meticulously conducts an anthropogenic impact assessment, dissecting forest fragmentation and forest fires across distinct chapters. The research is designed to assess and analyze the impact of anthropogenic activities on forest fragmentation and fires systematically. To achieve these objectives, the research employs a robust methodology integrating various research techniques and tools. The investigation delves into the historical context and background of anthropogenic activities in the Korean Peninsula, offering insights into the evolving landscape. The dissertation unfolds in four chapters, with Chapter 1 and Chapter 2 dedicated to the exploration of forest fragmentation. Leveraging spatial analysis, satellite imagery, machine learning, and impact assessment methodologies, these chapters delve into the intricate dynamics of forest fragmentation. The research methodologically emphasizes spatial analysis techniques to unveil the spatial patterns and extent of forest fragmentation, utilizing advanced tools for a nuanced understanding of the landscape. Chapters 3 and 4 shift the focus to anthropogenic forest fires, employing spatial analysis, machine learning, and vulnerability assessment methodologies. These chapters scrutinize the spatial dynamics and impact of forest fires, emphasizing the need for proactive measures to mitigate their destructive consequences. The research methodically employs spatial analysis techniques to understand the spatial distribution and intensity of forest fires, incorporating machine learning algorithms for predictive modeling and assessing vulnerability. In detail, the chapter 1: North Korea being one of the most degraded forests globally has recently been emphasizing in forest restoration. Monitoring the trend of forest restoration in North Korea has important ref-erence significance for regional environmental management and ecological security. Thus, this study constructed and analyzed a time-series land use land cover (LULC) map to identify the LULC changes (LULCCs) over extensive periods across North Korea and understand the forest change trends. The analysis of LULC used Landsat multi-temporal image and Random Forest algorithm on Google Earth Engine(GEE) from 2001 to 2018 in North Korea. Through the LULCC detection technique and consideration of the cropland change relation with elevation, the forest change in North Korea for 2001–2018 was evaluated. I extended the existing sampling methodology and obtained a higher overall accuracy (98.2% ± 1.6%), with corresponding kappa coefficients (0.959 ± 0.037), and improved the classification accuracy in cropland and forest cover. Through the change detection and spatial analysis, our research shows that the forests in the southern and central re-gions of North Korea are undergoing restoration. The sampling method I extended in this study can effectively and reliably monitoring the change trend of North Korea forests. It also provides an important reference for the regional environmental management and ecological security in North Korea. The chapter 2: One method of understanding landscape pattern changes is through an understanding of land use/land cover (LULC) changes, which are closely related to landscape pattern changes. Previous studies have monitored LULC changes across North Korea but did not consider landscape changes at a local scale. Using multiple LULC products to construct sample points, the LULC was classified using a random-forest algorithm and Landsat satellite dataset. The overall accuracy of the classification was 97.66 ± 1.36%, and the Kappa coefficient was 0.95 ± 0.03. Based on the classification results, landscape indices were used to quantify and monitor landscape pattern changes. The results showed that, from 2000 to 2020, there was an increasing trend in built-up and forest areas in Pyongyang, while cropland showed a decreasing trend, and landscape fragmentation increased. However, urban expansion was not the main factor affecting fragmentation. The main factors were forest recovery and cropland reduction, leading to an increase in landscape fragmentation in Pyongyang. The chapter 3: Forest fires are one of the most frequently occurring natural hazards, causing substantial economic loss and destruction of forest cover. As the Gangwon-do region in Korea has abundant forest resources and ecological diversity as Korea's largest forest area, spatial data on forest fire susceptibility of the region are urgently required. In this study, a forest fire susceptibility map (FFSM) of Gangwon-do was constructed using Google Earth Engine (GEE) and three machine learning algorithms: Classification and Regression Trees (CART), Random Forest (RF), and Boosted Regression Trees (BRT). The factors related to climate, topography, hydrology, and human activity were constructed. To verify the accuracy, the area under the receiver operating characteristic curve (AUC) was used. The AUC values were 0.846 (BRT), 0.835 (RF), 0.751 (CART). Factor importance analysis was performed to identify the important factors of the occurrence of forest fires in Gangwon-do. The results show that the most important factor in the Gangwon-do region is slope. A slope of approximately 17° (moderately steep) has a considerable impact on the occurrence of forest fires. Human activity and interference are the other important factors that affect forest fires. The established FFSM can support future efforts on forest resource protection and environmental management planning in Gangwon-do. The chapter 4: In recent years, the frequency of forest fires in Gangwon-do has increased due to increased climate change and dry weather. The Gangwon-do area has rich forest resources and ecological diversity as the largest forest area in South Korea, so there is an urgent need for more effective monitoring and prevention of forest fires. This study is based on multi-layer hazards approach and machine learning algorithms for multi-hazard probability map of two associated hazards (forest fire and drought) for monitoring Forest Fire High Susceptibility Area. First, extreme drought years were selected using the standardized precipitation index (SPI) and an inventory map of drought was constructed using the enhanced vegetation index (EVI) based on satellite image data. Then, 70% of the inventory maps based on forest fire and drought were used to construct hazard susceptibility maps and 30% were used for validation of three machine learning models: Classification and Regression Trees (CART), Random Forest (RF). Boosted Regression Trees (BRT). And 11 conditioning factors related to climate, topography, hydrology and human activities were considered for the analysis. The results of the three models were then validated using the Area under the ROC (Receiver operating characteristic) curve (AUC) and the best performing model was selected (BRT; Forest Fire: 85%, Drought: 80%). Finally, the susceptibility maps of forest fire and drought were combined to construct the multi-hazard probability map (MHPM) for the Gangwon Province, South Korea. The results show that the multi-hazard probability map (MHPM) of forest fire and drought constructed in this study is valid and reliable. This multi-hazard map can provide key information for planners and decision makers to develop forest fire prevention and management plans, and to more effectively prevent and reduce the frequency of forest fires. The overarching goal of this dissertation is to conduct a comprehensive anthropogenic impact assessment, dissecting the intricacies of forest fragmentation and forest fires. By approaching these issues in distinct chapters, the study aims to provide a detailed and actionable understanding of their implications. The findings of this research will contribute to the development of effective management strategies, crucial for sustaining forest health, preserving biodiversity, and mitigating the escalating threats posed by anthropogenic activities in the Korean Peninsula. 본 연구는 산림 파편화와 산불의 인위적 문제를 해결하고 산림 생태계에 미치는 중요한 영향을 평가하고 관리하는 것을 목표로 한다. 이러한 효과의 실질적인 의미를 이해하는 데 있어 현재의 과제는 종합적인 연구가 필요하다. 본 논문에서는 지형, 기후 등 지역적 특성을 고려한 맞춤형 산림관리의 중요성을 강조하고 있다. 특히 산림 파편화와 인위적 산불이 생물 다양성에 미치는 위협과 파괴적인 영향을 강조한다. 이 연구는 산림 건강과 생물 다양성을 유지하기 위한 효과적인 관리 전략 개발에 중점을 두고, 별도의 장에서 산림 분열과 산불을 분석하는 인위적 영향 평가를 수행한다.

임신중독증 태반에서 세포고사의 발현

이연혜 연세대학교 대학원 2001 국내석사

세포사멸 과정은 이전부터 알려져 온 전형적인 괴사와 세포고사로 나눌 수 있다. 1990년대에 들어서 분자 생물학 분야가 발전됨에 따라 세포고사에 관계된 일부 유전자의 역할이 밝혀지면서 이에 대한 연구가 활발해졌고 퇴행성 질환이나 종양의 발생과 치료, 정상조직의 발생과 소멸과정 등에서 세포고사의 역할을 밝히려는 연구가 진행되어 왔다. 산부인과 영역에서도 배란 이후 난포의 퇴행과정, 자궁내막의 월경주기에 따른 생성과 탈락 등에서 세포고사가 일어난다는 연구 결과가 있고 최근 몇 년 사이에는 착상이후 태반의 성장과 노화, 분만과정에서도 세포고사가 발생한다는 연구보고가 있었다. 비정상적인 태반의 착상과정과 태반의 혈류부전, 태아의 발육제한 등을 고려할 때 임신중독증 시 정상임신과 구별되는 세포사의 특징을 나타낼 것이라 생각되어 본 연구를 시행하였다. 연구대상은 1995년부터 1998년까지 23 주에서 40 주까지의 중증의 임신중독증 또는 전자간증, 자간증으로 입원하여 분만한 환자 39명과 20주 이후 분만한 환자중 태반의 병적 조직소견을 보이지 않고 태반조직을 확보할 수 있었던 33명을 대상으로 하였고 DNA fragmentation detection kit와 Bcl-2 단일클론 항체를 이용하여 대조군의 태반과 임신중독증 산모의 태반에서의 DNA fragmentation과 Bcl-2 단백의 발현여부를 비교하였다. 그 결과 첫째, 임신중독증의 산모에서 대조군에 비해 DNA fragmentation의 발현 비율이 더 낮았고 bcl-2 발현은 대조군에서 임신중독증 환자보다 대조군에서 억제되어 나타나 임신중독증 환자에서 세포고사의 경향을 파악하기가 어려웠다. 둘째, 자궁동맥 혈류 파형에서 notch를 보여 순환장애를 의심했던 경우의 환자 군과 그렇지 않은 경우를 각각 비교해 보았는데 순환장애를 보인 경우에는 DNA fragmentation이 많이 나타났고 Bcl-2의 발현이 적어 세포고사가 촉진되는 경향을 보였다. 셋째, 임신중독중 환자의 병리조직 검사 상에서 합포체성 결절(syncytial knots)과 경색소견을 보였던 경우와 특징적인 소견을 나타내지 않았던 태반조직에서 각각 비교해 보면 병리조직 검사상 임신중독증의 특징적인 소견을 보였던 경우에 DNA fragmentation이 현저하게 감소되어 있었고 Bcl-2의 발현이 증가한 것으로 나타나 세포고사가 억제되는 경향을 보였고 병리조직 검사 상에서 특징적인 소견이 없었던 임신중독증 환자 군에서 세포고사가 증가되는 경향을 보였다. 넷째, 대조군에서 임신 주 수별로 주 수에 맞게 성숙된 태반과 그렇지 않은 태반을 구별해서 관찰하였는데 대조군 태반에서 주 수에 맞게 성숙한 태반과 주 수에 비해 미성숙한 태반의 경우, 특징적인 세포고사의 경향을 보이지 않았고 세포고사에 의한 태반의 성숙과정에 미치는 영향을 찾기 어려웠다. 이상의 결과로 볼 때 본 연구에서 이용한 TUNEL 방법에 의한 DNA fragmentation과 면역조직화학염색에 의한 Bcl-2의 발현을 분석함으로써 임신중독증의 병태 생리에서 태반의 세포고사의 역할을 명확히 밝히기 어려우나 임신중독증의 진행과정에 따라 일시적인 세포고사의 진행이나 억제가 모두 나타날 수 있다는 결과를 얻었고 이에 대해서 좀 더 깊은 연구가 필요할 것으로 생각되었다. The process of natural cell death can be classified as necrosis or apoptosis. As the molecular biology continues to be developed, several genes and their roles in apoptosis has been identified and attempts have been made to determine that apoptosis is involved in the development and progression of numerous degenerative diseases, growth and treatment of neoplasm, and organogenesis and regression of normal tissues. In the field of obstetrics and gynecology, there are some reports that apoptosis occurs during regression of follicles after ovulation and in the endometrium based on the menstrual cycle. Recently studies have reported that apoptosis was involved in placental aging process after implantation and parturition. Because the pathogenesis of toxemia might be caused by abnormal implantation and uteroplacental insufficiency and intrauterine growth restriction, we hypothesize that apoptosis in toxemia is quite frequently compared to normal pregnancy. This study has been carried out with 39 patients who had severely induced hypertension during pregnancy and who eventually delivered from 23 to 40 gestational weeks, in addition to 33 cases who delivered after 20 weeks and had no pathologic findings of placenta. We compared the DNA fragmentation and expression of Bcl-2 protein in the placentas of toxemia and normotensive patients using a DNA fragmentation detection kit and Bcl-2 monoclonal antibodies. The results showed that first of all, DNA fragmentation in the pregnancy- induced hypertension patients were less than control group and Bcl-2 expression were greater than control group. Second, it showed that more DNA fragmentation and less Bcl-2 expression were observed with the notch of Doppler ultrasound, then we discovered that the apoptosis was accelerated with uteroplacental insufficiency. Third, DNA fragmentation was less than in the group of pregnancy-induced hypertension patients with syncytial knots and infarct and Bcl-2 was more evident in similar groups comparing with no pathologic pregnancy-induced hypertension patients' characteristics. Forth, no significant difference in DNA fragmentation and Bcl-2 expression was observed in the mature placentas as compared with the immature placentas in control group according to gestational weeks. From the results of this study, we found that it was difficult to clearly determine placental apoptosis in the pathology of pregnancy-induced hypertension, although both progress and restraint of momentary apoptosis might be found according to the process of pregnancy-induced hypertension with DNA fragmentation and Bcl-2 expression by immunohystochemistry. This means that further studies on this subject is necessary.

소와 돼지 정자에 있어서 활성산소계가 정자 기능과 지방산화 및 DNA 절편화에 미치는 영향

류범용 中央大學校 2000 국내박사

Many-Body Condensate Fragmentation in a Single Trap: Theory of Detection and Phase State Characterization

강명균 서울대학교 대학원 2016 국내박사

임계온도 이하의 희박한 원자기체는 계 전체에 걸친 큰 결맞음 등으로 흥미로운 물리 분야 중 하나이다. 이 저온 양자기체는 계의 변수들을 조정하기 용이하고, 외부의 원치 않는 간섭이 매우 적게 들어온다는 장점이 있다. 이런 점들이 하나의 거시적으로 점유된 모드(mode), 혹은 에너지 레벨, 를 이용해 보즈-아인슈타인 응집체(BEC)의 물리를 설명하고 묘사할 수 있게 한다. 본 논문에서, 파편화된 상태(fragmented state)-둘 혹은 더 많은 수의 거시적인 모드들이 존재하는 상태-를 다루었으며 둘 이상의 거시적인 모드들 간의 상관관계가 어떤 흥미로운 효과를 가져올 수 있을지 살펴보았다. 그를 위해 파편화된 상태의 정의를 소개하고, 더 나아가 자명한 파편화된 상태인 이중 우물에서의 파편화된 상태를 걸러내기 위한 분류를 시도하였다. 파편화된 상태는, 절대 온도가 0으로 가는 극한에서 상호작용이 증가함에 따라 보즈-아인슈타인 응집체로부터 전이된 다체계 바닥 상태로써 나타날 것으로 생각된다. 거시적인 모드들은, 임계온도보다 높은 온도에 있는 이상기체들처럼 운동량 상태의 밀도행렬을 통해 단순하게 다루는 것이 불가능하다. 따라서 계에 대한 추가적인 제한이나 미리 알려진 특성 없이, 거시적인 모드들의 오비탈과 모드들의 점유수 등을 변분법적으로 계산하는 것은 수치적으로도 매우 힘든 일이다. 이 논문에서 다루는 다체계를 비균질 적인 하나의 덫 안에 있는 준-1차원 원자 기체로 한정하여, 거시적인 모드가 두 개인 경우(1+1) 에 대해 다루려 하였다. 두 개의 거시적인 모드들로 구성된 유효 해밀토니안을 얻기 위해 장 연산자(field operator)를 두 번째 항까지 전개하고 잘라내었으며, 이는 그로스-피타예브스키 방정식에서 조금 더 나아가는 것이다. 이론을 준-1차원계의 함수로 얻기 위해 다른 방향들은 적분하였다. 그리고 원래 보즈-아인슈타인 응집체로 존재하는 거시적인 모드는 주로 가우시안이나 토마스-페르미 모양이며 짝수 패리티를 갖는다. 파편화된 상태는 상호작용을 제외한 에너지가 필연적으로 증가하므로, 추가되는 거시적인 모드를 홀수 패리티를 주어 덫 포텐셜의 영향을 줄이고 상호작용을 통해 에너지를 상대적으로 낮추기 위해 기존의 모드와 크게 겹치게 선택하였다. 이렇게 되는 경우, 제한적인 변분적 계산으로 에너지 방정식을 풀면, 상호작용의 세기가 올라감에 따라 파편화된 상태가 보즈-아인슈타인 응집체보다 더 낮은 에너지를 가지게 된다. 이 파편화된 상태는 상당한 크기의 음의 짝결맞음(pair coherence)를 가지고 있으며 이는 짝 터널링 항에 연관된다. 이 파편화된 상태는 거의 축퇴된 두 파편화된 상태들이 있으며, 작은 터널링 항에 의해 둘의 대칭 혹은 반대칭 중첩 상태 중 하나로 수렴하게 된다. 공간 결맞음 (spatial coherence)와 밀도-밀도 상관함수가 파편화된 상태의 고유의 특징을 잡아내는지에 대해 연구되었다. 밀도-밀도 상관함수의 강한 요동이 Time-of-Flight (TOF)이후에 존재하며, 이는 이중 우물에서 파편화된 상태의 Hanburry-Brown-Twiss (HBT) 상관관계와 비교되었다. 독립적인 두 보즈-아인슈타인 응집체들의 간섭 무늬 형성에 대해 좋은 해석을 준 위상 상태(phase state)를 이용해 단일 덫 안의 파편화된 상태에 대한 추가적인 해석을 하고자 하였고, 이를 일반적인 두개의 모드로 이루어진 상태에 대해 적용하기 위한 조건을 찾았다. 단일 덫 안의 파편화된 상태가 180도의 위상차이를 갖는 두 위상 상태의 중첩임을 알게 되었고, 파편화의 조건을 위상 상태를 이용해 표현함으로써 파편화된 상태와 특이한 상관함수간의 관계에 대해 조명하였다. 근사 결맞음 상태(approximate coherent state) 형식을 만들어, 파편화된 상태에 대한 추가적인 해석을 시도하였다. 위상 상태와 근사 결맞음 상태를 비교함으로써, 광자 고양이 상태와 파편화된 상태 간의 유사 관계에 대한 단서를 얻어 단일 덫 안의 파편화된 상태가 근사 결맞음 상태들의 중첩 상태, 즉 고양이 상태로 보여지는지에 대해 연구되었다. 일반적인 음의 짝결맞음 상태(NPC state)와 근사 결맞음 상태들의 중첩 상태간의 계수간의 관계를 찾아 유사 관계를 확립할 수 있었다. 더 나아가, 밀도-밀도 상관함수의 요동과 직교 위상 요동관의 직접적인 관계에 대해서도 다루었다. Dilute atomic gas below the critical temperature has been a field of interest due to its long-range, large coherence among over the whole system. Also parameters of the atomic gas system can easily be engineered with less unwanted external disturbance. And Bose-Einstein Condensate (BEC) is described by one macroscopically occupied mode (macroscopic mode) as a mean field together with small quantum fluctuations. In this thesis, a fragmented state which has two or more macroscopic mode in bosonic system, is investigated to find whether there exists interesting effects from correlation between macroscopic modes. Firstly, definition of fragmented state is introduced and further classification is presented to exclude trivial cases such as fragmented state appearing in a double well. Emergence of fragmented state is claimed as a ground state transition from BEC of the system in zero temperature limit. Macroscopic modes cannot be simply dealt with density matrix in terms of momentum eigenstates as in homogeneous thermal gas. Hence it is impossible to get the exact variational calculation considering spatial orbitals of each modes and occupation numbers without enough specification of system and constraints. In this thesis we consider a quasi-1d gas in a single inhomogeneous but symmetric (e.g. harmonic) trap, in order to seek for two-mode fragmentation. Field operator is truncated to obtain effective Hamiltonian for two macroscopic modes, which is just one step beyond the Gross-Pitaevskii (GP) equation. Then specification of the system into quasi-1d case is done by integrating out the other directions. And original macroscopic mode is considered to be e.g. Gaussian or Thomas-Fermi (TF) with even parity which are popular model describing BEC, since we consider fragmented state to stem from BEC as interaction strength increases. Fragmented state has larger single particle energy than BEC, thus odd parity of additional macroscopic mode with large overlap between the original mode in magnitude is assumed to minimize increase of single particle energy by introducing additional mode. Fragmented state satisfying energy equation has lower energy than BEC state as repulsive interaction strength goes up from limited variational calculation. This fragmented state has significant, and negative pair coherence related to pair tunneling term. There exist almost degenerate two fragmented states. They collapse for very small tunneling perturbation into symmetric, anti-symmetric superpositions which is stable fragmented states. Spatial coherence and density-density correlation are investigated for detection of unique characteristic(s) in the fragmented state. Strong fluctuation of density-density correlation after Time-of-Flight (TOF) is discussed, and is compared to double well case which has Hanburry-Brown-Twiss (HBT) correlation. Phase state is introduced, which is useful in analyzing interference between two independent BECs, to interpret fragmented state in a single trap further. Condition to apply phase state formalism for general two-mode state is studied, and phase state relates fragmented state to a superposition of two phase states of opposite phases. Furthermore, condition for fragmentation in terms of phase state coefficient is stated which can support the relation between fragmented state and peculiar correlation function. Approximate coherent state is established, to further fertilize and broaden the possible interpretation on fragmented state. By comparing phase state and approximate coherent state, a clue is found which leads us to the analogy between fragmented state and photonic cat state. To identify fragmented state as cat state, superposition of approximate coherent states of opposite phases, an expression of two-mode state in terms of approximate coherent state basis is investigated. Relation between coefficients of two different types of superpositions were found by transforming generalized expression of negative pair coherent (NPC) state including fragmented state, into a superposition of approximate coherent states. Further, direct relation between fluctuation in density-density correlation and quadrature fluctuation is discussed.

(The) role of the superoxide dismutases in iron regulation and vacuole physiology in Cryptococcus neoformans

김동현 중앙대학교 대학원 2021 국내석사

많은 병원성 진균에서 철분은 다양한 세포 과정에 필요하며 병원성 인자의 발현에 있어서 중요한 역할을 한다. 진균의 액포는 다양한 스트레스에 의해 형태를 바꾸는 세포 소기관이며, 다양한 효소를 갖고 있으며, 아미노산을 저장하거나 여러 이온, 특히 철분을 저장하는 기능을 갖고 있다. 때문에 액포의 기능은 진균의 병원성을 발현하는데 있어서 중요하다. 예를 들어, Cryptococcus neoformans에서 철 대사 또는 액포 기능이 결핍된 돌연변이체는 캡슐이나 멜라닌 합성과 같은 병원성 인자의 발현에 결함을 보인다. 추가로 모델 진균 Saccharomyces cerevisiae에서 액포가 산화 스트레스에 의해 절편화되는 모습을 보였고, 항산화 작용을 하는 Superoxide dismutase (SOD)가 결핍되었을 때도 액포가 절편화되는 모습을 보였다. 또한, SOD가 결핍되면, 철 항상성에서 중요한 역할을 하는 철-황 클러스터가 산화되어 비활성화되기 때문에, SOD는 철 항상성에 있어서도 중요한 역할을 한다. 이런 점들로, C. neoformans에서 SOD의 철 조절과 액포 형태에서의 역할에 대해 알아보고자 했다. 높은 철분 농도 조건에서 Mn-Superoxide dismutase인 Sod2 단백질의 발현이 증가하고 SOD2가 없는 돌연변이체에서 철 조절 단백질인 Cir1과 HapX의 발현이 크게 감소하는 것을 발견했고, 액포의 절편화가 현저하게 증가하는 것을 발견했다. 액포 절편화는 Cu, Zn-Superoxide dismutase를 암호화하는 SOD1이 결여된 돌연변이체에서도 증가했지만, 액포 절편화 수준은 sod2 돌연변이체에서 더 높았다. 또한 높은 농도의 철분, 구리 또는 아연 배지에서 자란 야생형 균주의 액포 절편화가 크게 증가하는 것을 관찰했다. 이러한 모든 조건은 세포 내 활성 산소 종을 증가시키는 조건이었으며, 이는 액포의 절편화가 산화 스트레스에 의해 발생함을 시사했다, 그리고 C. neoformans에서 액포의 절편화는 S. cerevisiae와 유사하게 TORC1 및 Fab1에 의해 조절되는 것을 발견했다. 흥미롭게도, Sod2의 위치가 낮은 농도의 구리 또는 철분 농도, 파고라이소솜 내에서 변하는 것을 발견했고, 이 조건들에서 Sod2는 미토콘드리아 뿐만 아니라 세포질에서도 발견되었다. 최종적으로, C. neoformans에서 액포의 절편화는 산화 스트레스에 의해 일어났으며, Sod2는 철 항상성에도 영향을 미친다는 것을 확인했다. In many pathogenic fungi, iron is required for various cellular processes and plays an important role in the expression of virulence factors. The yeast vacuoles are cellular organelles that change their morphology by various stresses, and the vacuole contains various enzymes and has the function of storing amino acids or various ions, especially iron. Therefore, the vacuolar function is important for virulence. For example, in Cryptococcus neoformans, mutants deficient in iron metabolism or vacuolar function showed defects in the expression of virulence factors such as capsule or melanin synthesis. In addition, in Saccharomyces cerevisiae, the yeast model organism, vacuoles were fragmented by oxidative stress, and vacuoles were fragmented even when superoxide dismutase (SOD), an antioxidant, was deficient. In addition, SOD also plays an important role in iron homeostasis, since iron-sulfur clusters, which play an important role in iron homeostasis, are oxidized and deactivated when SOD is deficient. With these points, I aimed to investigate the iron regulation of SOD in C. neoformans and its function in the vacuole morphology. It was showed that the expression of Sod2 was increased in high-iron condition, and the expression of iron regulatory proteins Cir1 and HapX was greatly decreased and vacuole fragmentation was significantly increased in a mutant lacking SOD2, which encodes Mn-superoxide dismutase. The vacuole fragmentation was also increased in a mutant lacking SOD1, which encodes Cu, Zn-superoxide dismutase, but the level of vacuole fragmentation was higher in the sod2 mutant. Additionally, I observed a significant increase in vacuole fragmentation of wild-type cells grown in high-iron, copper, or zinc media. Furthermore, growth at 37℃ and antifungal drug fluconazole treatment also increased vacuole fragmentation. All of these conditions increased intracellular reactive oxygen species, suggesting that vacuole fragmentation is caused by oxidative stress. And it was discovered that vacuole fragmentation in C. neoformans is regulated by TORC1 and Fab1, similar to S. cerevisiae. Interestingly, I found that the localization of Sod2 was changed at low-copper or iron concentrations, and under these conditions Sod2 was found not only in mitochondria but also in the cytoplasm. Finally, it was confirmed that vacuole fragmentation in C. neoformans was caused by oxidative stress, and that Sod2 also affects iron homeostasis.

수면 분절 유발 쥐의 해마조직에서 Inflammasome의 활성화 연구

좌훈정 고려대학교 대학원 2016 국내박사

ABSTRACT A study on inflammasome activation in rat hippocampus subjected to sleep fragmentation. Hoon-Jung Jwa Director: Chol Shin, MD, PhD Korea University Seoul, South Korea Continuation of sleep is important for body health and cognitive function. Several experimental studies have been conducted to clarify the exact mechanisms underlying the effect of sleep fragmentation (SF) on cognitive functions, but it remains still unknown. It has been reported that up-regulation of Nod-like receptor 3 (NLRP3) inflammasome is associated with several kinds of chronic diseases such as diabetes and insulin resistance. In this study, I investigated whether SF affects the NLRP3 activation in rat hippocampus using a walking wheel system. 7-weeks old eight male Wistar rats were used for SF model validation. Four and eight day sleep fragmentation was accomplished by a forced walking wheel system with a wheel on/off cycle of 30-s on/90-s off to mimic the arousal that is common in patients with severe sleep apnea. Time interval of exercise control (EC) was set at 10 min on/30 min off. Then, forty-eight male Wistar rats were randomly divided into the 4-day SF group, 4-day EC group, 8-day SF group, and 8-day EC group. Western blot analysis revealed that SF induced up-regulation of NLRP3 inflammasome complex. In accordance with the expression level of the complex, malondialdehyde levels were more increased in the SF group than in the EC group. There were no significant changes in ATP levels between 4 and 8 day SF groups and corresponding EC groups, indicating that SF-induced activation of NLRP3 is independent of ATP levels. I found that SF induced activation of NLRP3 inflammasome in rat hippocampus. A further study is required to clarify the role of NLRP3 inflammasome in SF-associated cognitive impairments. Keywords Sleep fragmentation; Nod-like receptor 3; Inflammasome; Western blot; Malondialdehyde