Rational Design and Evaluation of a Branched-Chain-Containing Glycolipid Antigen That Binds to CD1d

Baek, Dong Jae,Lee, Yoon-Sook,Lim, Chaemin,Lee, Doohyun,Lee, Taeho,Lee, Jae-Young,Lee, Kyoo-A,Cho, Won-Jea,Kang, Chang-Yuil,Kim, Sanghee Wiley (John WileySons) 2010 Chemistry - An Asian Journal Vol.5 No.7

Synthesis and Biological Evaluation of a Polyyne-Containing Sphingoid Base Probe as a Chemical Tool

Lee, Yun Mi,Lim, Chaemin,Lee, Hun Seok,Shin, Young Kee,Shin, Kyong-Oh,Lee, Yong-Moon,Kim, Sanghee American Chemical Society 2013 Bioconjugate chemistry Vol.24 No.8

<P>The sphingolipid metabolites have emerged as a starting point for the development of novel therapeutics for many diseases. However, details of the functions and mechanisms of sphingolipids remain unknown. To better understand the roles of sphingolipids, chemical tools with unique biological and physicochemical properties are needed. In this regard, we previously reported the synthesis of sphingoid base analogues in which the carbon chains are restricted by triple bonds. Here, we have conjugated a fluorescent dye to the polyyne analogues of the sphingoid bases to generate optical probes. Like the parent polyyne-containing sphingoid base, the 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD)-labeled triyne-sphingosine inhibited cancer cell growth far more effectively than did the corresponding sphingosine. NBD-triyne-sphingosine was rapidly incorporated into the cells and displayed broad cytoplasmic distribution. According to the results of a flow cytometric analysis, cancer cells fed with NBD-triyne-sphingosine showed significantly increased fluorescence intensity compared with the NBD-sphingosine treated cells. The metabolism of NBD-triyne-sphingosine was somewhat different from that of NBD-sphingosine. These results indicated that the incorporated rigid polyyne moiety in the sphingoid base altered the physicochemical properties of the sphingolipid, thereby affecting its biological behavior. The higher antiproliferative activity in the SRB assay and the significantly higher fluorescence intensity observed in the flow cytometric analysis are some of the interesting and distinct aspects of NBD-triyne-sphingosine compared to standard NBD-sphingosine probes. Thus, it is believed that the fluorescently labeled polyyne-containing sphingoid base developed in this study will be a useful chemical tool in sphingolipid research.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/bcches/2013/bcches.2013.24.issue-8/bc300684q/production/images/medium/bc-2012-00684q_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/bc300684q'>ACS Electronic Supporting Info</A></P>

Electron Transfer to Hydroxylase through Component Interactions in Soluble Methane Monooxygenase

( Chaemin Lee ),( Yunha Hwang ),( Hyun Goo Kang ),( Seung Jae Lee ) 한국미생물 · 생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.3

The hydroxylation of methane (CH₄) is crucial to the field of environmental microbiology, owing to the heat capacity of methane, which is much higher than that of carbon dioxide (CO₂). Soluble methane monooxygenase (sMMO), a member of the bacterial multicomponent monooxygenase (BMM) superfamily, is essential for the hydroxylation of specific substrates, including hydroxylase (MMOH), regulatory component (MMOB), and reductase (MMOR). The diiron active site positioned in the MMOH α-subunit is reduced through the interaction of MMOR in the catalytic cycle. The electron transfer pathway, however, is not yet fully understood due to the absence of complex structures with reductases. A type II methanotroph, Methylosinus sporium 5, successfully expressed sMMO and hydroxylase, which were purified for the study of the mechanisms. Studies on the MMOH-MMOB interaction have demonstrated that Tyr76 and Trp78 induce hydrophobic interactions through π-π stacking. Structural analysis and sequencing of the ferredoxin domain in MMOR (MMOR-Fd) suggested that Tyr93 and Tyr95 could be key residues for electron transfer. Mutational studies of these residues have shown that the concentrations of flavin adenine dinucleotide (FAD) and iron ions are changed. The measurements of dissociation constants (K_ds) between hydroxylase and mutated reductases confirmed that the binding affinities were not significantly changed, although the specific enzyme activities were significantly reduced by MMOR-Y93A. This result shows that Tyr93 could be a crucial residue for the electron transfer route at the interface between hydroxylase and reductase.

Towards improving finite element solutions automatically with enriched 2D solid elements

Chaemin Lee,San Kim 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.76 No.3

In this paper, we propose an automatic procedure to improve the accuracy of finite element solutions using enriched 2D solid finite elements (4-node quadrilateral and 3-node triangular elements). The enriched elements can improve solution accuracy without mesh refinement by adding cover functions to the displacement interpolation of the standard elements. The enrichment scheme is more effective when used adaptively for areas with insufficient accuracy rather than the entire model. For given meshes, an error for each node is estimated, and then proper degrees of cover functions are applied to the selected nodes. A new error estimation method and cover function selection scheme are devised for the proposed adaptive enrichment scheme. Herein, we demonstrate the proposed enrichment scheme through several 2D problems.

A new design concept for ocean nuclear power plants using tension leg platform

Chaemin Lee,Jaemin Kim,Seongpil Cho 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.76 No.3

This paper presents a new design concept for ocean nuclear power plants (ONPPs) using a tension leg platform (TLP). The system-integrated modular advanced reactor, which is one of the successful small modular reactors, is mounted for demonstration. The authors define the design requirements and parameters, modularize and rearrange the nuclear and other facilities, and propose a new total general arrangement. The most fundamental level of design results for the platform and tendon system are provided, and the construction procedure and safety features are discussed. The integrated passive safety system developed for the gravity based structure-type ONPP is also available in the TLP-type ONPP with minor modifications. The safety system fully utilizes the benefits of the ocean environment, and enhances the safety features of the proposed concept. For the verification of the design concept, hydrodynamic analyses are performed using the commercial software ANSYS AQWA with the Pierson-Moskowitz and JONSWAP wave spectra that represent various ocean environments and the results are discussed.

The strain-smoothed MITC3+ shell finite element

Lee, Chaemin,Lee, Phill-Seung Elsevier 2019 Computers & structures Vol.223 No.-

<P><B>Abstract</B></P> <P>In this paper, we propose the strain-smoothed MITC3+ shell finite element. The membrane strain field of the continuum mechanics based 3-node triangular shell element (MITC3+) is smoothed using the recently developed strain-smoothed element (SSE) method. The strain-smoothed MITC3+ shell element passes basic tests (patch, isotropy and zero energy mode tests) and shows significantly improved membrane behavior in various numerical examples. The major advantage of the SSE method is that no additional degree of freedom is required for solution improvement.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The strain-smoothed MITC3+ shell finite element is proposed. </LI> <LI> The membrane strain of the MITC3+ element is improved using the strain-smoothed element method. </LI> <LI> The strain-smoothed element does not require special smoothing domains and additional DOFs. </LI> <LI> Through various numerical examples, its improved performance is demonstrated. </LI> </UL> </P>

『쇼미더머니 시즌3』를 통해 살펴본 한국 힙합의 진정성

이채민(Lee, Chaemin),김재범(Kim, Jaibeom) 한국문화산업학회 2015 문화산업연구 Vol.15 No.2

힙합 오디션 프로그램인 『쇼미더머니』시리즈를 통해 최근 힙합과 관련된 담론이 형성되고 있다. 『쇼미더머니』는 그간의 일반적인 음악 오디션 프로그램과는 달리 힙합이라는 하나의 장르에만 초점을 맞추어 진행되어 음악 애호가들과 일반 대중들의 큰 관심을 끌었다. 그러나 타 장르에 비해 수용의 역사가 짧은 힙합은 미국 본토와의 제 문화사회적 차이로 인하여, 장르의 성격에 대해 합의가 이루어지지 않은 부분들이 발견된다. 그 중에서도 ‘어떻게 해야 진정한 힙합인가?’라는 근본적인 물음을 상기시키는 힙합의 진정성에 대한 논의는 현재 진행형이다. 예술의 진정성(authenticity)에 대한 담론은 발터 벤야민의 고전적인 아우라(aura) 개념으로부터 확인해볼 수 있다. 벤야민 이후에도 사회학과 문화학, 음악학 등 제 분야에서 진정성 개념을 재해석하고 있는데, 크게 작품 및 창작자 측면과 수용자 및 사회 측면 두 가지 모두를 포괄하는 개념이라 정의할 수 있다. 본 연구에서는 『쇼미더머니』시리즈 중 가장 최근에 종영한 시즌3을 통하여 현재 한국 힙합에서 요구되는 진정성이 무엇인지에 대하여 주목해보고자 한다.『쇼미더머니3』에서 현저하게 드러난 부분은 창작자의 진정성인데, 특히 아이돌 출신이 정통 힙합에 도전한다는 사실에 대하여 프로그램 안팎으로 상당한 논란을 불러 일으켰다. 창작자의 출신 배경이 힙합의 진정성에 미치는 영향에 대하여 살펴보고, 현재의 한국 힙합이 생각해보아야 할 진정성 함의에 대해 고찰해보는 것이 본 연구의 의의이자 목적이다. Authenticity has long been discussed in arts. Recently, there is an ongoing debate on the authenticity in popular culture in general and in popular music in particular. In popular music, discussions concerned with authenticity has been notably in folk and rock. Yet, hip hop is another genre that deserves discussions on authenticity. In the United States where hip hop has its roots, hip hop has long beenmostly enjoyed by youth in the lower class in the city. Hip hop has been synonymous with violence, crime and other anti-social activities. Hip hop has been introduced to Korea in the late 1980s. Hip hop in Korea has been popular tomiddle class youth quite oftenwith experiences in foreign countries. Hip hop fanbase has long been limited. Local Music TV channel M.net has launched a hip hop audition program "Show me the money". this audition program has contributed to the wider acceptance of hip hop in terms of age and gender. A hot issue surrounding hip hop is the authenticity. Authenticity has long been discussed in various disciplines ranging from philosophy and sociology to popular music studies. Authenticity in hip hop comes from two some what different perspectives. One is the authenticity of the hip hop artist. Authenticity come from his personal background and how the artist has made his way in life. The other is concerned with the authenticity of the audience and society. These two aspects can help to explain the authenticity of hip hop. In Korea, central issue is concernedwith the first aspect.More specifically, the authenticity of idol hip hop, a rapper froman idol group. Showme the money has shown how an intial prejudice against the idol hiphopper can be gradually changed over the course, winding up the idol rapper to win the competition. 힙합 오디션 프로그램인 『쇼미더머니』시리즈를 통해 최근 힙합과 관련된 담론이 형성되고 있다. 『쇼미더머니』는 그간의 일반적인 음악 오디션 프로그램과는 달리 힙합이라는 하나의 장르에만 초점을 맞추어 진행되어 음악 애호가들과 일반 대중들의 큰 관심을 끌었다. 그러나 타 장르에 비해 수용의 역사가 짧은 힙합은 미국 본토와의 제 문화사회적 차이로 인하여, 장르의 성격에 대해 합의가 이루어지지 않은 부분들이 발견된다. 그 중에서도 ‘어떻게 해야 진정한 힙합인가?’라는 근본적인 물음을 상기시키는 힙합의 진정성에 대한 논의는 현재 진행형이다. 예술의 진정성(authenticity)에 대한 담론은 발터 벤야민의 고전적인 아우라(aura) 개념으로부터 확인해볼 수 있다. 벤야민 이후에도 사회학과 문화학, 음악학 등 제 분야에서 진정성 개념을 재해석하고 있는데, 크게 작품 및 창작자 측면과 수용자 및 사회 측면 두 가지 모두를 포괄하는 개념이라 정의할 수 있다. 본 연구에서는 『쇼미더머니』시리즈 중 가장 최근에 종영한 시즌3을 통하여 현재 한국 힙합에서 요구되는 진정성이 무엇인지에 대하여 주목해보고자 한다.『쇼미더머니3』에서 현저하게 드러난 부분은 창작자의 진정성인데, 특히 아이돌 출신이 정통 힙합에 도전한다는 사실에 대하여 프로그램 안팎으로 상당한 논란을 불러 일으켰다. 창작자의 출신 배경이 힙합의 진정성에 미치는 영향에 대하여 살펴보고, 현재의 한국 힙합이 생각해보아야 할 진정성 함의에 대해 고찰해보는 것이 본 연구의 의의이자 목적이다. Authenticity has long been discussed in arts. Recently, there is an ongoing debate on the authenticity in popular culture in general and in popular music in particular. In popular music, discussions concerned with authenticity has been notably in folk and rock. Yet, hip hop is another genre that deserves discussions on authenticity. In the United States where hip hop has its roots, hip hop has long beenmostly enjoyed by youth in the lower class in the city. Hip hop has been synonymous with violence, crime and other anti-social activities. Hip hop has been introduced to Korea in the late 1980s. Hip hop in Korea has been popular tomiddle class youth quite oftenwith experiences in foreign countries. Hip hop fanbase has long been limited. Local Music TV channel M.net has launched a hip hop audition program "Show me the money". this audition program has contributed to the wider acceptance of hip hop in terms of age and gender. A hot issue surrounding hip hop is the authenticity. Authenticity has long been discussed in various disciplines ranging from philosophy and sociology to popular music studies. Authenticity in hip hop comes from two some what different perspectives. One is the authenticity of the hip hop artist. Authenticity come from his personal background and how the artist has made his way in life. The other is concerned with the authenticity of the audience and society. These two aspects can help to explain the authenticity of hip hop. In Korea, central issue is concernedwith the first aspect.More specifically, the authenticity of idol hip hop, a rapper froman idol group. Showme the money has shown how an intial prejudice against the idol hiphopper can be gradually changed over the course, winding up the idol rapper to win the competition.

Development of a robust pH-sensitive polyelectrolyte ionomer complex for anticancer nanocarriers

Lim, Chaemin,Youn, Yu Seok,Lee, Kyung Soo,Hoang, Ngoc Ha,Sim, Taehoon,Lee, Eun Seong,Oh, Kyung Taek Dove Medical Press 2016 INTERNATIONAL JOURNAL OF NANOMEDICINE Vol.11 No.-

<P>A polyelectrolyte ionomer complex (PIC) composed of cationic and anionic polymers was developed for nanomedical applications. Here, a poly(ethylene glycol)–poly(lactic acid)–poly(ethylene imine) triblock copolymer (PEG–PLA–PEI) and a poly(aspartic acid) (P[Asp]) homopolymer were synthesized. These polyelectrolytes formed stable aggregates through electrostatic interactions between the cationic PEI and the anionic P(Asp) blocks. In particular, the addition of a hydrophobic PLA and a hydrophilic PEG to triblock copolyelectrolytes provided colloidal aggregation stability by forming a tight hydrophobic core and steric hindrance on the surface of PIC, respectively. The PIC showed different particle sizes and zeta potentials depending on the ratio of cationic PEI and anionic P(Asp) blocks (C/A ratio). The doxorubicin (dox)-loaded PIC, prepared with a C/A ratio of 8, demonstrated pH-dependent behavior by the deprotonation/protonation of polyelectrolyte blocks. The drug release and the cytotoxicity of the dox-loaded PIC (C/A ratio: 8) increased under acidic conditions compared with physiological pH, due to the destabilization of the formation of the electrostatic core. In vivo animal imaging revealed that the prepared PIC accumulated at the targeted tumor site for 24 hours. Therefore, the prepared pH-sensitive PIC could have considerable potential as a nanomedicinal platform for anticancer therapy.</P>

비대면 회의 참여자간 사회적 실재감의 인터렉션 향상 방안 제안 - 화상회의 플랫폼 Zoom, Webex, Teams 중심으로 -

이채민(Chaemin Lee),이하리(Hari Lee),차민영(Minyoung Cha),최나은(Naeun Choi),윤재영(Jaeyoung Yun) 한국HCI학회 2024 한국HCI학회 논문지 Vol.19 No.1

본 연구는 코로나19에 따른 판데믹 이후 보편화된 비대면 온라인 화상회의 플랫폼의 인터렉션 향상 방안을 제안한다. 비대면 회의에서 실제와 같이 이뤄지는 소통은 사회적 실재감이라는 개념으로 정의 가능하며, 본 연구에서는 Swan의 사회적 실재감 모델을 지표로 하여 온라인 화상회의 플랫폼의 주요 기능을 진단했다. 이를 통해 각 기능별 사회적 실재감을 향상시킬 수 있는 방안을 발견했다. 현재 플랫폼의 주요 기능을 진단하기 위해 시장에서 가장 활발하게 활용되는 플랫폼 3가지(Zoom, Webex, Teams)를 선정하였다. 사회적 실재감은 정서적, 상호 작용적, 응집적 실재감으로 나뉘는데 각 실재감에 해당하는 기능을 선별하여 3가지 플랫폼에서 동일 기능을 사용하여 참여자들이 회의를 진행하도록 설계했다. 실험 대상은 20-30대 남/여 12명으로 실제 화상회의를 진행하는 Task를 수행하는 경험을 관찰하여 정성적 결과를 도출했다. 실험 결과 온라인 플랫폼을 활용한 비대면 소통 시 사회적 실재감 향상 시키는데 온라인 플랫폼 화면에서 실시간적으로 나타내는 시각적 피드백의 중요성이 나타났다. 이는 같은 공간에 있을 때 무의적으로 상대의 행동, 표정 등 분위기를 파악할 수 있는 정보가 한정적이기 때문이다. 화상회의 플랫폼에서 제공하는 기본적인 시각 요소인 비디오(카메라) 비시각적 요소인 소리, 행동, 기분을 시각적인 피드백으로 강화하는 것이 비대면 상황에서도 사회적 실재감을 높여주는 요소임을 확인하였다. 본 연구는 비대면 회의 참여자간 사회적 실재감 향상 방안을 제시하는데 의의가 있다. This study proposes strategies to enhance interaction on widely adopted non-face-to-face online video conferencing platforms that have become prevalent following the COVID-19 pandemic. Communication in virtual meetings, mirroring real-world interactions, can be defined by the concept of social presence. In this study, we examined the key features of online video conferencing platforms using Swans social presence model as an indicator. Through this analysis, we identified methods to improve social presence for each function of the platform. To assess the current features of the platforms, we selected the three most widely used platforms in the market (Zoom, Webex, Teams). Social presence was categorized into emotional, interactional, and cohesive presence, and specific features corresponding to each presence were identified. Participants were instructed to engage in meetings using the same features across the three platforms, and the study observed the experiences of 12 participants in their 20s and 30s performing tasks during actual video conferences. The results of the experiment underscored the importance of real-time visual feedback displayed on the online platform for enhancing social presence during non-face-to-face communication. This significance stems from the limited ability to unconsciously perceive information such as the other partys actions, expressions, and overall atmosphere when physically present in the same space. The study confirmed that reinforcing basic visual elements provided by video (camera) and enhancing non-visual elements such as sound, behavior, and mood through visual feedback are critical factors for increasing social presence in non-face-to-face situations using video conferencing platforms. This research is significant in presenting strategies for enhancing social presence among participants in virtual meetings.

Experimental and numerical investigations of near-field underwater explosions

Seunggyu Lee,Junghee Cho,Chaemin Lee,Seongpil Cho 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.77 No.3

Near-field underwater explosion (UNDEX) phenomena were investigated by experiments and numerical simulations. The UNDEX experiments were performed in a water tank using a ship-like model. One kilogram of TNT, one of the most widely used military high explosives, was used for the experiments. Numerical simulations were performed under the same conditions as in the experiments using the commercial software LS-DYNA. Underwater pressures, accelerations, velocities, and strains by shock waves were measured at multiple locations. Further, the bubble pulsation period and the whipping deformations of the ship-like model were explored. The experimental results are presented and examined through comparison with the results obtained from widely used empirical equations and numerical simulations.