• BMB Reports
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• v.29 no.1
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• pp.32-37
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• 1996

The cysteine 43, potentially important in the activity of O-acetylserine sulfhydrylase (OASS) from Salmonella typhimurium, has been changed to serine. This mutant enzyme (C43S) has been studied in order to gain insight into the structural basis for the binding of inhibitor, substrate and product. UV-visible spectra of C43S exhibit the same spectral change in the presence of OAS as that observed with wild type enzyme, indicating C43S will form an ${\alpha}$-aminoacrylate Schiff base intermediate. At pH 6.5, however, the deacetylase activity of C43S is much higher than wild type enzyme indicating that cysteine 43 plays a role in stabilizing the ${\alpha}$-aminoacrylate intermediate. The fluoroscence spectrum of C43S exhibits a ratio of emission at 340 to 502 nm of 16.9, reflecting the lower fluorescence of PLP and indicating that the orientation of cofactor and tryptophan are different from that of the wild type enzyme. The emission spectrum of C43S in the presence of OAS gives two maxima at 340 and 535 nm. The 535 nm emission is attributed to the fluoroscence of the ${\alpha}$-aminoacrylate intermediate. The visible circular dichroic spectrum was similar to wild type enzyme, but the negative effect observed at 530~550 nm and the molar ellipicity values for the mutant are decreased by about 50% compared to wild type enzyme. The circular dichroic and fluoroscence studies suggest binding of the cofactor is less asymmetric in C43S than in the wild type enzyme.

• Molecules and Cells
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• v.41 no.3
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• pp.214-223
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• 2018

Oligoadenylate synthetase (OAS) protein family is the major interferon (IFN)-stimulated genes responsible for the activation of RNase L pathway upon viral infection. OAS-like (OASL) is also required for inhibition of viral growth in human cells, but the loss of one of its mouse homolog, OASL1, causes a severe defect in termination of type I interferon production. To further investigate the antiviral activity of OASL1, we examined its subcellular localization and regulatory roles in IFN production in the early and late stages of viral infection. We found OASL1, but not OASL2, formed stress granules trapping viral RNAs and promoted efficient RLR signaling in early stages of infection. Stress granule formation was dependent on RNA binding activity of OASL1. But in the late stages of infection, OASL1 interacted with IRF7 transcripts to inhibit translation resulting in down regulation of IFN production. These results implicate that OASL1 plays context dependent functions in the antiviral response for the clearance and resolution of viral infections.

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.203-203
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• 2002

Cytomegalovirus (CMV), a beta-herpesvirus with worldwide distribution, exhibits host persistence, a distinguishing characteristic of all herpesviruses. This persistence is dependent upon restricted gene expression in infected cells as well as the ability of productively infected cells to escape from normal cell-mediated anti-viral immunosurveillance. Type I (IFN-α/β) and type II (IFN-γ) interferons are major components of the innate defense system against viral infection. They are potent inducers of MHC class I and II antigens and of antigen processing proteins. Additionally, IFNS mediate direct antiviral effects through induction effector molecules that block viral infection and replications such as 2′, 5-oligoadenylate synthetase (2, 5-OAS). IFNS function through activation of well-defined signal transduction pathways that involve phosphorylation of constituent proteins and ultimate formation of active transcription factors. Recent studies have shown that a number of diverse viruses, including CMV, EBV, HPV mumps and Ebola, are capable of inhibiting IFN-mediated signal transduction through a variety of mechanisms. As an example, CMV infection inhibits the ability of infected cells Is transcribe HLA class I and II antigens as well as the antiviral effector molecules 2, 5-OAS and MxA I. EMSA studies have shown that IFN-α and IFN-γ are unable to induce complete signal transduction in the presence of CMV infection, phenomena that are associated with specific decreases in JAKl and p48. Viral inhibition of IFN signal transduction represents a new mechanistic paradigm for increased viral survival, a paradigm predicting widespread consequences in the case of signal transduction factors common to multiple cytokine pathways.

• Journal of Microbiology
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• v.38 no.4
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• pp.203-208
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• 2000

Cytomegalovirus (CMV), a beta-herpesvirus with worldwide distribution, exhibits host persistence, a distinguishing characteristic of all herpesviruses. This persistence is dependent upon restricted gene expression in infected cells as well as the ability of productively infected cells to escape from normal cell-mediated anti-viral immunosurveillance. Type I (IFN-$\alpha$/$\beta$) and type II (IFN-γ) interferons are major components of the innate defense system against viral infection. They are potent inducers of MHC class I and II antigens and of antigen processing proteins. Additionally, IFNS mediate direct antiviral effects through induction effector molecules that block viral infection and replications such as 2', 5-oligoadenylate synthetase (2, 5-OAS). IFNS function through activation of well-defined signal transduction pathways that involve phosphorylation of constituent proteins and ultimate formation of active transcription factors. Recent studies have shown that a number of diverse viruses, including CMV, EBV, HPV mumps and Ebola, are capable of inhibiting IFN-mediated signal transduction through a variety of mechanisms. As an example, CMV infection inhibits the ability of infected cells Is transcribe HLA class I and II antigens as well as the antiviral effector molecules 2, 5-OAS and MxA I. EMSA studies have shown that IFN-$\alpha$ and IFN-γ are unable to induce complete signal transduction in the presence of CMV infection, phenomena that are associated with specific decreases in JAKl and p48. Viral inhibition of IFN signal transduction represents a new mechanistic paradigm for increased viral survival, a paradigm predicting widespread consequences in the case of signal transduction factors common to multiple cytokine pathways.

• Journal of Korean Neurosurgical Society
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• v.29 no.4
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• pp.514-520
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• 2000

Objective : Stereotactic psychosurgery is known as one of effective means of treating in some medically intractable psychiatric illness. However, it is unfamiliar and it's long-term clinical result has not reported in our country. The authors evaluated its long-term results of pscychosurgery and discussed its neuroanatomical basis. Methods : Since 1993, eight patients underwent stereotactic psychosurgery for medically intractable psychiatric illnesses. All were referred from psychiatrist of these disorders, one was aggressive behavior, five were obsessive-compulsive disorders(OCD), and two were depression with anxiety disorders. Bilateral amygdalotomy and subcaudate tractotomy were done for aggressive behavior, and limbic leukotomy was done for OCD and depression with anxiety. The results of OCD were evaluated with with YBOCS(Yale-Brown obsessive compulsive scale) and VAS (visual analogue scale), CGI(clinical global impairment) in OCD, and OAS(overt aggression scale), MMS, WAIS were checked for the evaluation of aggressive behavior. Hamilton depression scale(HAMD) was used for evaluation of depression. Ventriculography was used in the first five patients and MR-guided stereotaxy was used in recent three cases for localization of target. The lesions were made with radiofrequency lesion generator. Results : With long-term follow up(mean 45 months) in five OCDs, mean YBOCS declined from 34 to 3(n=5). All returned to previous social life. In OAS scores of aggressive behavior during six-year follow up, scores declined from 8 to 2 with clinical improvement. In two patients with depression with anxiety, HAMD declined from 28.5 to 16.5(n=2). There was no operative mortality and no significant morbidity except one case of mild transient urinary incontinence. Conclusion : With these long-term results, authors assumed that stereotactic psychosurgery could be one of safe and effective mtherapeutic methods in several medically intractable psychiatric illness.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.16-16
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• 2023

Metabolomics is the study of global metabolite profiles in a system (cell, tissue, or organism) under a given set of conditions. Metabolomics has its roots in early metabolite profiling studies but is now a rapidly expanding area of scientific research in its own right. In this study, the applications of metabolomics in natural product studies are explored. Ginseng is a well-known herbal medicine and has various pharmacological effects, which include antiaging, anticancer, antifatigue, memory enhancing, immunomodulatory, and stress reducing effects. Metabolomic analysis of organic acids has not been performed for evaluation whether ginseng has been cultivated using conventional or environmental-friendly farming methods. In this study, profiling analysis was conducted for organic acids (OAs) in ginseng roots produced using conventional or environmentfriendly farming methods at five locations in each of five regions. In OA profiles, lactic acid was the most abundant OA in all regions, with the exception for environmentally friendly farmed ginseng in two of the five regions, in which glycolic acid was most abundant OA. OA profiles in all regions showed isocitric acid levels were increased by environment-friendly cultivation, which suggests metabolic differences associated from farming method, and that isocitric acid might be a useful discriminatory biomarker of environmental-friendly and conventional cultivation. The results of the present study suggest metabolomic studies of OAs in ginseng roots might be useful for monitoring whether ginseng has been cultivated using conventional or environmentally friendly farming methods.

• Aerospace Industry
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• s.107
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• pp.66-67
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• 2010

공용어로 스페인어를 사용하며 통화는 미국 달러를 사용하는 에콰도르 공화국(Republic del Ecuador)은 남아메리카 북서부에 위치한 중소국가다. 미주 기구(OAS), 석유수출국 기구(OPEC), 남아메리카 국가 연합(UNASUR), 라틴어 연합(Latin Union) 등에 가입되어 있고 활발한 대외활동을 펼치고 있다. 그럼에도 불구하고 사실 에콰도르의 대외 위상은 그리 높지 않다. 생태학적으로 중요한 갈라파고스 제도가 에콰도르의 영토라는 사실을 아는 사람이 극히 적을 정도로 에콰도르는 우리에게 먼 나라다. 그러나 최근 에콰도르는 항공우주분야에서 급격한 두각을 나타내고 있다. 2007년 11월 설립된 에콰도르 민간 우주기구(La Agencia Espacial Civil Ecuatoriana)를 중심으로 우주개발에 적극 뛰어들고 있기 때문이다. 에콰도르 최초의 우주인을 배출하고 주요 항공우주 선진국과 협력을 강화해 나가고 있는 에콰도르 민간 우주기구의 활약을 소개한다.

• Journal of Distribution Science
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• v.12 no.10
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• pp.47-56
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• 2014

Purpose - This study aims to eradicate and halt the continuous life cycle of corruption. Only when ethical management policies are implemented can the business ethics system be effective and transparent. Research design, data, and methodology - The analyses and legislative measures designed by these organizations and countries were based on solid research, uncovered during my visits and interviews conducted with businessmen in those countries. Results - The main focus of in this study is as follows: First, to introduce the programs of UN, OECD, OAS, USA, and Asian countries noted for business ethics and transparency policies; Second, to define each function and problem of these countries' anti-corruption systems, including the U.S. federal government, and to examine Chinese trends. Conclusions - Ethical managements are necessary to improve business ethics. This study suggests four related areas for the purpose of discouraging bribery and corruption; these are improving global corporate governance standards, increasing financial transparency, improving good governance in the public service of the OECD member countries, and focusing on not only the supply side but also the demand side of the corruption market.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.179-179
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• 2012

Low pressure radio-frequency glow discharges are investigated using theoretical modeling and various experimental diagnostic methods. In the calculations, global models and transformer models are developed to understand the chemical kinetics as well as the electrical properties such as the effective collision frequency, the heating mechanism and the power transferred to the plasma electrons. In addition, Boltzmann equation solver is used to compensate the effect of the electron energy distribution function (EEDF) shape in the global model, and the general expression of energy balance for non-Maxwellian electrons is developed. In the experiments, a number of traditional plasma diagnostic methods are used to compare with calculated results such as Langmuir probe, optical emission spectroscopy (OES), optical absorption spectroscopy (OAS) and two-photon absorption laser-induced fluorescence (TALIF). These theoretical and experimental methods are applied to understand several interesting phenomena in low pressure ICP discharges. The chemical and physical properties of low pressure ICP discharges are described and the applications of these methods are discussed.

• Journal of International Area Studies (JIAS)
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• v.14 no.2
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• pp.449-476
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• 2010

This paper focuses on the security problems in atlantic ocean involved in the USA and Latin America and the Caribbean. The ocean security matters in this region have mainly argued military concerns traditionally. However, the concept of ocean security has been changed in the 21st century and strongly debated with various dimensions: social, human and resource, environment as well. This paper traces these changed concepts currently with many empirical cases existed in many security conflicts in this ocean, especially between the USA and Latin(South) America region. Historically, security conflicts in the OAS(Organization of American States) countries have involved with many military matters, territory and oceans, and currently added up with terrorism and drug problems as well. However, the great and potential conflict emerged in the security issues is resource matter in this ocean and get a dilemma to be sorted out between military and social security matter. For example, the re-establishment of 'the 4th Fleet' in US Navy got a great conflict between the USA and the South American countries, both of them wants to achieve to resource security in this ocean to meet their energy security. Finally this paper addresses some implications and prospects in this conflict in near future and suggests a few solutions and advices for Korean's relation in this ocean.