동시베리아 바타가이 메가슬럼프의 두 얼음층에서의 온실기체 형성에 관한 생지화학적 연구

학위논문(석사) -- 서울대학교대학원 : 자연과학대학 지구환경과학부, 2023. 8. 안진호.Permafrost can be a significant source of greenhouse gases (GHGs) under global warming in the future. However, the source and control mechanisms of GHGs in permafrost regions are not well understood. Ice wedges, commonly found in subsurface permafrost regions, contain gas bubbles with very high concentration of GHGs. Analysis of GHGs in the gas bubbles may help us better understand control mechanisms of GHG formation at subzero temperature in permafrost regions. The Batagay megaslump, which is located in the Yana Highlands of northern Yakutia, is the largest thaw slump in the world. Here, I used ice-wedge samples from two stratigraphic units: the Upper Ice Complex (UIC) and the Lower Ice Complex (LIC) of the Batagay megaslump. I estimated the ice-wedge formation processes by analyzing the Ar/N2/O2 compositions of the gas bubble and stable water isotopic ratios (δ18O and δD) of the wedge ice. Then, the sources and control mechanisms of GHGs in the occluded gas within the ice wedge were constrained by analyzing carbon stable isotopes of the GHGs (CO2, CH4) and the sediment particles included in the wedge ice, the relationships between the mixing ratios of GHGs (CO2, N2O, CH4), and various soluble inorganic ionic compositions of the wedge ice. The Ar/N2/O2 compositions indicated that the studied ice wedges were likely formed through dry snow or hoarfrost compaction, and microbial activity remained active after ice wedge formation. The δ18O and δD values of the ice suggested colder winter temperatures in the UIC compared to the LIC. CO2 and CH4 primarily originated from biogenic sources. N2O showed exclusive correlation with CH4, and its mixing ratios vary at different depths, likely due to differences in the microbiome. These findings suggest that GHG formation in ice wedges is not solely controlled by physiochemical conditions but involves a complex interplay between microbial activity and environmental conditions. Our study contributes to a better understanding of the dynamics involved in GHG formation within permafrost.영구동토층은 미래의 지구 온난화 상황에서 온실 가스(GHGs)의 중요한 원천이 될 수 있다. 그러나 영구동토층 지역에서의 온실가스의 형성 메커니즘은 잘 이해되지 않고 있다. 영구동토 지역에서 흔히 볼 수 있는 얼음 쐐기에는 매우 높은 농도의 온실기체를 함유한 버블이 포함되어 있으며, 이 가스 버블 내의 온실기체 분석을 통해 영구동토 지역, 특히 영하의 온도에서 온실기체 형성 메커니즘을 더 잘 이해할 것이라 기대한다. 우리는 북동시베리아 야쿠시아(Yakutia)의 야나 (Yana) 고원에 위치한 세계에서 가장 큰 해동 슬럼프인 바타가이 메가슬럼프의 상부 얼음 복합체(UIC)와 하부 얼음 복함체(LIC)에서 얼음쐐기 샘플을 사용하여 온실기체 농도 분석을 진행하였다. 우리는 가스 버블의 Ar/N2/O2 조성과 얼음의 물동위원소 비율 (δ18O 및 δD)을 분석하여 얼음 쐐기 형성 과정을 추정하였다. 그런 다음, 이산화탄소와 메탄의 탄소 안정 동위원소와 얼음 쐐기에 포함된 퇴적 입자, 온실기체의 혼합 비율과 이온 조성 간의 관계를 분석함으로써 얼음 쐐기 내부 온실기체의 기원과 형성 메커니즘을 제안하였다. 연구 지역의 얼음 쐐기는 건조한 눈이나 서리가 압착되어 형성되었을 것으로 보이며, 얼음 쐐기 형성 이후에도 미생물 활동이 존재하여 온실기체를 형성하였을 것으로 보인다. 특히, 아산화질소의 경우, 혼합 비율이 LIC에서 더 적었는데, 이러한 결과는 미생물 군집의 차이가 있었기 때문으로 보인다. 이러한 결과는 얼음쐐기 내에서 온실기체 형성이 물리화학적 조건뿐만 아니라 미생물 활동과 환경 조건 사이의 복잡한 상호작용을 포함한다는 것을 시사한다.Chapter 1. Introduction 1 Chapter 2. Site and sample description 5 Chapter 3. Materials and Methods 7 3.1 Gas extraction and mixing ratio measurements 7 3.2 Stable water isotope analysis 9 3.3 Soil and major ion chemistry 10 3.4 Stable carbon isotopes for greenhouse gas 11 Chapter 4. Results 12 4.1 Stable water isotopes 12 4.2 N2, O2 and Ar mixing ratios 13 4.3 Greenhouse gas mixing ratios 14 4.4 Soil and ion properties 15 4.5 δ13C for greenhouse gas 16 Chapter 5. Discussion 17 5.1 Batagay ice wedge formation and related climate conditions 17 5.2 Origin of GHGs within ice wedges 20 5.2.1 Carbon dioxide, CO2 23 5.2.2 Methane, CH4 24 5.2.3 Nitrous oxide, NO2 26 Chapter 6. Conclusion 31 References 32 Abstract in Korean 38 Lisf of Figures 39 List of Tables 47석

전체 게놈 검색법을 이용한 몽골 민족 HDL 콜레스테롤 유전자 자리에 관한 연구

학위논문(박사) --서울대학교 대학원 :의학과 생화학 전공,2007.Docto

cDNA Microarray를 이용한 항암제 투여에 따른 폐암세포주 유전자발현 변화 연구

학위논문(석사)--서울대학교 대학원 :의학과 생화학전공,2001.Maste

A Study on the stress of files and canal transportation in a curved canal

학위논문(박사)--서울대학교 대학원 :치의학과 치과보존학전공,1998.Docto

A study on the sol gel transition behavior of PEO-(polyalkylene succinate)-PEO triblock copolymer solution

학위논문(석사) - 한국과학기술원 : 생명화학공학과, 2002.8, [ vi, 55 p ]한국과학기술원 : 생명화학공학과

CYTOTOXICITY OF RESIN-BASED ROOT CANAL SEALER, ADSEAL

The properties of ideal root canal sealers include the ability of sealing the total root canal system and no toxic effects to periradicular tissues. Cytotoxicity test using cell culture is a common screening method for evaluation of the biocompatibility of root canal sealers. The purpose of this study was to investigate the cytotoxic effect of newly developed resin-based sealer (Adseal 1, 2, and 3) comparing with those commercial resin-based sealers (AH26 and AH Plus), ZOE-based sealers (Tubliseal EWT, Pulp Canal Sealer EWT) and calcium hydroxide based sealer (Sealapex), An indirect contact test of cytotoxicity by agar diffusion was performed according to the international standard ISO 10993-5. L929 fibroblast cells were incubated at in humidified 5% air atmosphere. The freshly mixed test materials were inserted into glass rings of internal diameter 5 mm and height 5 mm placed on the agar. After the 24 hrs incubation period, the decolorization zones around the test materials were assessed using an inverted microscope with a calibrated screen. A Decolorization Index was determined for each specimen. Adseal 1. 2, and 3 did not exert any cytotoxic effects, whereas AH26, AH Plus, Tubliseal EWT, Pulp Canal Sealer EWT, and Sealapex produced mild cytotoxicity.보건복지부 보건의료기술연구개발사

Genomic alterations in BCL2L1 and DLC1 contribute to drug sensitivity in gastric cancer

Gastric cancer (GC) is the third leading cause of cancer-related deaths worldwide. Recent high-throughput analyses of genomic alterations revealed several driver genes and altered pathways in GC. However, therapeutic applications from genomic data are limited, largely as a result of the lack of druggable molecular targets and preclinical models for drug selection. To identify new therapeutic targets for GC, we performed array comparative genomic hybridization (aCGH) of DNA from 103 patients with GC for copy number alteration (CNA) analysis, and whole-exome sequencing from 55 GCs from the same patients for mutation profiling. Pathway analysis showed recurrent alterations in the Wnt signaling [APC, CTNNB1, and DLC1 (deleted in liver cancer 1)], ErbB signaling (ERBB2, PIK3CA, and KRAS), and p53 signaling/apoptosis [TP53 and BCL2L1 (BCL2-like 1)] pathways. In 18.4% of GC cases (19/103), amplification of the antiapoptotic gene BCL2L1 was observed, and subsequently a BCL2L1 inhibitor was shown to markedly decrease cell viability in BCL2L1-amplified cell lines and in similarly altered patient-derived GC xenografts, especially when combined with other chemotherapeutic agents. In 10.9% of cases (6/55), mutations in DLC1 were found and were also shown to confer a growth advantage for these cells via activation of Rho-ROCK signaling, rendering these cells more susceptible to a ROCK inhibitor. Taken together, our study implicates BCL2L1 and DLC1 as potential druggable targets for specific subsets of GC cases

An integrative approach to precision cancer medicine using patient-derived xenografts

Cancer is a heterogeneous disease caused by diverse genomic alterations in oncogenes and tumor suppressor genes. Despite recent advances in high-throughput sequencing technologies and development of targeted therapies, novel cancer drug development is limited due to the high attrition rate from clinical studies. Patient-derived xenografts (PDX), which are established by the transfer of patient tumors into immunodeficient mice, serve as a platform for co-clinical trials by enabling the integration of clinical data, genomic profiles, and drug responsiveness data to determine precisely targeted therapies. PDX models retain many of the key characteristics of patients’ tumors including histology, genomic signature, cellular heterogeneity, and drug responsiveness. These models can also be applied to the development of biomarkers for drug responsiveness and personalized drug selection. This review summarizes our current knowledge of this field, including methodologic aspects, applications in drug development, challenges and limitations, and utilization for precision cancer medicine. © The Korean Society for Molecular and Cellular Biology. All rights reserved

Nitric oxide-releasing polymer incorporated ointment for cutaneous wound healing

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