Genome-wide Transcriptional Regulatory Network of Methylomonas sp. DH-1 NtrC Reveals Regulatory Mechanisms of Nitrogen Utilization

Sukjae HAN,Joon Young PARK,Yong Hee HAN,Ina BANG,Ok Kyung LEE,Ji Sung HYUNG,Jeong-Geol NA,Eun Yeol LEE,Donghyuk KIM,Sang Woo SEO 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10

Methanotrophs, which utilize methane as a sole carbon source, are both a methane sink and a source of nitrogen oxides for the ecosystem. Since anthropogenic activities have increased greenhouse gases like methane and nitrous oxide, understanding nitrogen metabolism and its regulation of methanotroph becomes important. We elucidate the NtrC transcriptional regulatory network of type I methanotroph Methylomonas sp. DH-1. NtrC is a transcription factor that controls the expression of genes to respond environment perturbation mainly related to fixed nitrogen level. Multi-omics analysis with two different nitrogen sources, ammonium and nitrate, reveals that a total of 43 genes in 19 transcription units belong to NtrC regulon. Analysis of the NtrC regulon demonstrates that NtrC responsible to regulation of nitrogenase expression and reducing toxic effects of hydroxylamine and nitrite. Also, there are regulatory function involved in nitrate/nitrite assimilation, electron transfer complex and other regulatory components. This study reveals the characteristics of NtrC regulation in methanotrophs and offers the possibility to solve problems posed by anthropogenic environmental threats.

Berkeley on Continuous Creation

Sukjae Lee(이석재) 한국현상학회 2014 철학과 현상학 연구 Vol.62 No.-

“보존은 계속적 창조”라는 신학적 테제를 버클리가 폭넓게 자연세계에 적용시키고 있다는 윈클러의 해석에 반하여, 본 논문에서 버클리가 이 테제를 받아들이고 있다면 물리적인 대상에 국한하여 적용시키고 있다고 주장한다. 이어 필자는 계속적 창조 테제를 이렇게 제한적으로 적용시키는 태도는 버클리가 견지하는 기회원인론의 독특성, 곧 그의 “제한된” 기회원인론을 드러내준다고 주장한다. 달리 표현하자면, 버클리의 기회원인론은 신학적 테제들을 중심에 놓고 이에 근거하여 자연 세계 내에서의 신과 피조물의 인과력에 대한 입장을 개진시킨 결과로 보기 보다는, 신의 인과력을 그의 관념론에 잘 맞게끔 부합시키려는 노력의 결과로 보는 것이 자연스럽다는 주장을 편다. 이런 면에서 신학적 테제로부터 기회원인론을 이끌어낸, 이를 테면 ‘위로부터의’ 기회원인론을 주창한 말브랑슈와는 달리, 버클리는 ‘아래로부터의’ 기회원인론을 편다는 것이다. 이 ‘아래로부터의’ 기회원인론은 버클리 자신의 관념론적 형이상학이라는 정초위에서 기회원인론이 갖는 특정 설명적 장점 때문에 도입된다. 그러나 이렇게 도입된 기회원인론이 버클리의 형이상학에서 핵심적 역할을 하는 영혼의 활동성과 상충될 때 버클리는 과감히 기회원인론을 제한시키는데, 이러한 제한된 기회원인론을 견지하는 태도는 계속적 창조에 대한 버클리의 미온적 태도와 잘 들어맞는다는 것이 해석의 초점이다. Against Winkler’s interpretation that Berkeley endorses the “conservation is but continuous creation thesis” across-the-board, this paper argues that Berkeley restricts his endorsement of the continuous creation thesis to the domain of physical bodies. Such a restricted application of the continuous creation thesis, the paper goes on to argue, reveals the distinctive nature of Berkeley’s occasionalism, an occasionalism “contained.” That is, his occasionalism with regard to physical bodies is more a product of accommodating divine causality within his immaterialist metaphysics than a structuring of his metaphysics on the foundation of key theological considerations. In contrast to the “top-down” approach of Nicolas Malebranche, where foundational theological principles dictate the nature of the divine and creaturely causality in the world, resulting in a type of global occasionalism, in the case of Berkeley, the approach is better characterized as one that is “bottom up,” an occasionalism that finds its place after the basic setup of the metaphysical makeup of the world is in place. Consistent with this reading is the suggestion that Berkeley’s occasionalism thus restricted is motivated by the explanatory advantages of occasionalism than the theological claim that conservation is continuous creation.

Metabotropic glutamate receptor dependent long-term depression in the cortex

Sukjae Joshua Kang,Bong-Kiun Kaang 대한생리학회-대한약리학회 2016 The Korean Journal of Physiology & Pharmacology Vol.20 No.6

Metabotropic glutamate receptor (mGluR)-dependent long-term depression (LTD), a type of synaptic plasticity, is characterized by a reduction in the synaptic response, mainly at the excitatory synapses of the neurons. The hippocampus and the cerebellum have been the most extensively studied regions in mGluR-dependent LTD, and Group 1 mGluR has been reported to be mainly involved in this synaptic LTD at excitatory synapses. However, mGluR-dependent LTD in other brain regions may be involved in the specific behaviors or diseases. In this paper, we focus on five cortical regions and review the literature that implicates their contribution to the pathogenesis of several behaviors and specific conditions associated with mGluR-dependent LTD.

지자체 사이버 공간 안전을 위한 금융사기 탐지 텍스트 마이닝 방법

최석재(Sukjae Choi),이중원(Jungwon Lee),권오병(Ohbyung Kwon) 한국지능정보시스템학회 2017 지능정보연구 Vol.23 No.3

최근 SNS는 개인의 의사소통뿐 아니라 마케팅의 중요한 채널로도 자리매김하고 있다. 그러나 사이버 범죄 역시 정보와 통신 기술의 발달에 따라 진화하여 불법 광고가 SNS에 다량으로 배포되고 있다. 그 결과 개인정보를 빼앗기거나 금전적인 손해가 빈번하게 일어난다. 본 연구에서는 SNS로 전달되는 홍보글인 비정형 데이터를 분석하여 어떤 글이 금융사기(예: 불법 대부업 및 불법 방문판매)와 관련된 글인지를 분석하는 방법론을 제안하였다. 불법 홍보글 학습 데이터를 만드는 과정과, 데이터의 특성을 고려하여 입력 데이터를 구성하는 방안, 그리고 판별 알고리즘의 선택과 추출할 정보 대상의 선정 등이 프레임워크의 주요 구성 요소이다. 본 연구의 방법은 실제로 모 지방자치단체의 금융사기 방지 프로그램의 파일럿 테스트에 활용되었으며, 실제 데이터를 가지고 분석한 결과 금융사기 글을 판정하는 정확도가 사람들에 의하여 판정하는 것이나 키워드 추출법(Term Frequency), MLE 등에 비하여 월등함을 검증하였다. Recently, SNS has become an important channel for marketing as well as personal communication. However, cybercrime has also evolved with the development of information and communication technology, and illegal advertising is distributed to SNS in large quantity. As a result, personal information is lost and even monetary damages occur more frequently. In this study, we propose a method to analyze which sentences and documents, which have been sent to the SNS, are related to financial fraud. First of all, as a conceptual framework, we developed a matrix of conceptual characteristics of cybercriminality on SNS and emergency management. We also suggested emergency management process which consists of Pre-Cybercriminality (e.g. risk identification) and Post-Cybercriminality steps. Among those we focused on risk identification in this paper. The main process consists of data collection, preprocessing and analysis. First, we selected two words ‘daechul(loan)’ and ‘sachae(private loan)’ as seed words and collected data with this word from SNS such as twitter. The collected data are given to the two researchers to decide whether they are related to the cybercriminality, particularly financial fraud, or not. Then we selected some of them as keywords if the vocabularies are related to the nominals and symbols. With the selected keywords, we searched and collected data from web materials such as twitter, news, blog, and more than 820,000 articles collected. The collected articles were refined through preprocessing and made into learning data. The preprocessing process is divided into performing morphological analysis step, removing stop words step, and selecting valid part-of-speech step. In the morphological analysis step, a complex sentence is transformed into some morpheme units to enable mechanical analysis. In the removing stop words step, non-lexical elements such as numbers, punctuation marks, and double spaces are removed from the text. In the step of selecting valid part-of-speech, only two kinds of nouns and symbols are considered. Since nouns could refer to things, the intent of message is expressed better than the other part-of-speech. Moreover, the more illegal the text is, the more frequently symbols are used. The selected data is given ‘legal’ or ‘illegal’. To make the selected data as learning data through the preprocessing process, it is necessary to classify whether each data is legitimate or not. The processed data is then converted into Corpus type and Document-Term Matrix. Finally, the two types of ‘legal’ and ‘illegal’ files were mixed and randomly divided into learning data set and test data set. In this study, we set the learning data as 70% and the test data as 30%. SVM was used as the discrimination algorithm. Since SVM requires gamma and cost values as the main parameters, we set gamma as 0.5 and cost as 10, based on the optimal value function. The cost is set higher than general cases. To show the feasibility of the idea proposed in this paper, we compared the proposed method with MLE (Maximum Likelihood Estimation), Term Frequency, and Collective Intelligence method. Overall accuracy and was used as the metric. As a result, the overall accuracy of the proposed method was 92.41% of illegal loan advertisement and 77.75% of illegal visit sales, which is apparently superior to that of the Term Frequency, MLE, etc. Hence, the result suggests that the proposed method is valid and usable practically. In this paper, we propose a framework for crisis management caused by abnormalities of unstructured data sources such as SNS. We hope this study will contribute to the academia by identifying what to consider when applying the SVM-like discrimination algorithm to text analysis. Moreover, the study will also contribute to the practitioners in the field of brand management and opinion mining.

Hybrid dielectrics composed of Al2O3 and phosphonic acid self-assembled monolayers for performance improvement in low voltage organic field effect transistors

Jang Sukjae,Son Dabin,황선빈,Kang Minji,Lee Seoung-Ki,Jeon Dae-Young,Bae Sukang,Lee Sang Hyun,이동수,Kim Tae-Wook 나노기술연구협의회 2018 Nano Convergence Vol.5 No.20

Low voltage operational organic transistors (< 4 V) based on pentacene were successfully fabricated with hybrid dielectric films composed of aluminum oxide using atomic layer deposition and various phosphonic acid-based self-assembled monolayers as the gate dielectrics. High capacitances up to 279 nF/cm2, low leakage current densities of 10−8 A/cm2 at 6 V, and high breakdown fields up to 7.5 MV/cm were obtained. The transistors with the octadecylphosphonic acid hybrid dielectric exhibited an improved saturation mobility of 0.58 cm2/Vs, a subthreshold slope of 151 mV/decade, a threshold voltage of − 1.84 V and an on–off current ratio of 106. The low surface energies of the self-assembled monolayers having non-polar terminal groups, such as methyl and pentafluorophenoxy, improved the carrier conduction of the transistors due to the pentacene growth with an edge-on orientation for low voltage operation. The pentafluorophenoxy end-group showed an accumulation of holes at the semiconductor-dielectric interface.

Metabotropic glutamate receptor dependent long-term depression in the cortex

Kang, Sukjae Joshua,Kaang, Bong-Kiun The Korean Society of Pharmacology 2016 The Korean Journal of Physiology & Pharmacology Vol.20 No.6

Metabotropic glutamate receptor (mGluR)-dependent long-term depression (LTD), a type of synaptic plasticity, is characterized by a reduction in the synaptic response, mainly at the excitatory synapses of the neurons. The hippocampus and the cerebellum have been the most extensively studied regions in mGluR-dependent LTD, and Group 1 mGluR has been reported to be mainly involved in this synaptic LTD at excitatory synapses. However, mGluR-dependent LTD in other brain regions may be involved in the specific behaviors or diseases. In this paper, we focus on five cortical regions and review the literature that implicates their contribution to the pathogenesis of several behaviors and specific conditions associated with mGluR-dependent LTD.

Graphene nano-floating gate transistor memory on plastic.

Jang, Sukjae,Hwang, Euyheon,Cho, Jeong Ho RSC Pub 2014 Nanoscale Vol.6 No.24

<P>A transparent flexible graphene nano-floating gate transistor memory (NFGTM) device was developed by combining a single-layer graphene active channel with gold nanoparticle (AuNP) charge trap elements. We systematically controlled the sizes of the AuNPs, the thickness of the tunneling dielectric layer, and the graphene doping level. In particular, we propose that the conductance difference (i.e., memory window) between the programming and erasing operations at a specific read gate voltage can be maximized through the doping. The resulting graphene NFGTMs developed here exhibited excellent programmable memory performances compared to previously reported graphene memory devices and displayed a large memory window (12 V), fast switching speed (1 μs), robust electrical reliability (10(5) s), and good mechanical (500 cycles) and thermal stability (100 C).</P>

Philosophy in its Place and Time

Lee, Sukjae(이석재) 서울대학교 철학사상연구소 2013 철학사상 Vol.48 No.-

저자는 개인적 경험을 바탕으로 이 글에서 철학과 순수학문 교육의 쇠락이라는 현상을 한국과 미국을 비교하며 조망한다. 쇠락의 측면에서 양국이 비슷한 운명을 겪고 있지만 저자는 그 쇠락의 형태나 원인은 상이 하다고 분석한다. 이러한 상이성에 근거하여 저자는 각각의 역사적, 문화적, 사회적 배경에 근거하여 철학과 철학 교육의 역할 역시 규명, 추구 되어야 한다는 주장을 제시한다. This paper, on the basis of personal experience, examines the challenges that philosophy and the liberal arts in general face, and argues that, while the decline of philosophy and the liberal arts might be common to both Korea and the United States, the reasons behind such decline are distinct. Based on this diagnosis, the paper goes on to suggest how we might begin to address this decline by identifying the proper role of philosophy in relation to the social, historical, and cultural setting in which philosophy has its natural place.

온라인 뉴스 제목 분석을 통한 특정 장소 이벤트 성과 예측을 위한 형태소 분석 방법

최석재(Sukjae Choi),이재웅(Jaewoong Lee),권오병(Ohbyung Kwon) 한국전자거래학회 2016 한국전자거래학회지 Vol.21 No.1

공개된 데이터인 온라인 뉴스 기사 중 상당수는 도시와 같은 특정 장소에서 발생하는 이벤트에 관련된 사실과 의견을 담고 있어 독자의 의사 결정에 영향을 끼친다. 따라서 대량의 인터넷 뉴스 기사를 분석하면 향후 사람들이 특정 이벤트에 대하여 어떠한 선택을 할지 예상할 수 있을 것이다. 이에 본 연구는 온라인 뉴스 기사 제목을 형태소 분석하여 특정 장소에서 이루어질 이벤트의 성과를 사전에 예측하는 방법을 제안하고자 한다. 기사 제목은 기사의 가장 핵심적인 내용을 담고 있어 본문보다 사실과 의견이 더 정확하게 발현될 뿐 아니라, 모바일 환경에서는 기사 본문보다 더 큰 영향력을 가지기 때문에 이벤트의 성과 예측에 효과적인 자료이다. 이에 인터넷 뉴스 기사의 제목을 수집하여 학습 데이터와 평가 데이터로 구분하고, 학습 데이터에서 유의한 극성을 보이는 형태소를 추출하여 전체 기사의 제목을 감성 분석하였다. 여기에 뉴스기사가 갖는 특성이 반영될 수 있도록 기사 검색량과 기사 산출량 정보를 변인에 추가하여 이벤트 성과를 예측하는 알고리즘을 수립하였다. 그 결과 70.6%의 성공률로 성과를 예측하여 다른 비교 대상 분석 방법과 분명한 차이를 보였다. 도출된 이벤트 성과 예측 정보는 이벤트를 준비하는 기관 및 업체에서 예상 수요량을 결정할 때 도움을 줄 수 있을 것이다. Online news on the Internet, as published open data, contain facts or opinions about a specific affair and hence influences considerably on the decisions of the general publics who are interested in a particular issue. Therefore, we can predict the people’s choices related with the issue by analyzing a large number of related internet news. This study aims to propose a text analysis method to predict the outcomes of events that take place in a specific place. We used topics of the news articles because the topics contains more essential text than the news articles. Moreover, when it comes to mobile environment, people tend to rely more on the news topics before clicking into the news articles. We collected the titles of news articles and divided them into the learning and evaluation data set. Morphemes are extracted and their polarity values are identified with the learning data. Then we analyzed the sensitivity of the entire articles. As a result, the prediction success rate was 70.6% and it showed a clear difference with other analytical methods to compare. Derived prediction information will be helpful in determining the expected demand of goods when preparing the event.

영국의 재생에너지 정책에 대한 정치적 과정 연구

이석재(Sukjae Lee) 한국유럽학회 2017 유럽연구 Vol.35 No.3

한 국가 내부에서 국제제도가 요구하는 수준을 맞추기 위해 기후변화 정책과 재생에너지 제도를 도입하고자 할 때, 정책의 내용과 수준은 국가 별로 상이하다. 본 연구는 재생에너지 증진 정책을 분석함에 있어 총리와 유관부서와 같은 정책결정자들의 정치적 이익에 따라 결정된다고 주장한다. 위 주장을 검증하기 위해서 2000년부터 2015년까지를 기준으로 영국의 재생에너지증진 정책인 재생에너지 의무할당제도와 발전차액지원제도를 분석함으로서 사례분석을 시행하였다. 이를 통해 환경정책의 도입과 전환이 정치인들의 재선에 있어 도움이 되는 지와 함께 유관부서의 연합과 갈등에 따라 두 제도간 의 전환이 발생하게 된다. 이는 기후변화 이슈를 넘어선 전반적인 정책도입 과정을 분석함에 있어 중요한 점은 정책의 효과성이 아닌 정책결정자들의 정치가 중요하다는 점을 제공하는 분석결과라고 할 수 있다. When countries introduce climate change policies to meet international standards, the policy content and level of importance vary across countries. This study argues that the criteria politicians and officials use for analysis of renewable energy promotion policies are not based on the scientific recommendations for promoting renewable energy but determined only by the political interests of policy-makers such as the Prime Minister and relevant departments. To verify the argument, the study conducted a case analysis of the Renewable Obligation and the Feed-in Tariff―the UK`s renewable energy promotion policy programs―from 2000 to 2015. The results of the case analysis indicate that the difference in the choice between the two programs depends on which program is more in line with coalitions and conflicts of the related departments, as well as reelection of politicians. This finding suggests the importance of policymakers` politics in the analysis of the policy-making process in general that goes beyond the climate change issue.