In situ optical investigation of carbon nanotube growth in hot-filament chemical vapor deposition

Seungho Choi,Soonil Lee,Ken Ha Koh 한국물리학회 2006 Current Applied Physics Vol.6 No.1l

chemical vapor deposition (HFCVD) method using Fe catalysts pre-treated with argon plasma. The structural characteristics, such asthe thickness and surface roughness of CNT lms, deduced from the analysis of the optical reectivity while taking the scatteringdue to surface roughness into account were consistent with those estimated from ex situ SEM images. Moreover, the linear regressionanalysis of the temporal variation of reectivity revealed that an incubation period of. 50 s preceded the noticeable growth of CNTs,dropping rapidly, and that the active growth of CNTs up to tens of micrometer occurred in the short span of a few tens of seconds. Thus,in situ reectivity measurement can be used to investigate CNT growth, and may shed some light on the details of the CNT growth mech-anism in the HFCVD method.

Hydrogel micropost-based qPCR for multiplex detection of miRNAs associated with Alzheimer's disease

Choi, Woongsun,Yeom, Sang Yun,Kim, Junsun,Jung, Seungwon,Jung, Seungho,Shim, Tae Soup,Kim, Sang Kyung,Kang, Ji Yoon,Lee, Soo Hyun,Cho, Il-Joo,Choi, Jungkyu,Choi, Nakwon Elsevier Applied Science 2018 Biosensors & bioelectronics Vol. No.

<P><B>Abstract</B></P> <P>Quantitative polymerase chain reaction (qPCR) renders profiling of genes of interest less time-consuming and cost-effective. Recently, multiplex profiling of miRNAs has enabled identifying or investigating predominant miRNAs for various diseases such as cancers and neurodegenerative diseases. Conventional multiplex qPCR technologies mostly use colorimetric measurements in solution phase, yet not only suffer from limited multiplexing capacity but also require target-screening processes due to non-specific binding between targets and primers. Here, we present hydrogel micropost-based qPCR for multiplex detection of miRNAs associated with Alzheimer's disease (AD). Our methodology promises two key advantages compared with the conventional solution-based PCR: 1) nearly no non-specific crosstalks between targets and primers, and 2) practically valuable multiplexing by spatial encoding within a single microchamber. Specifically, we immobilized hydrogel microposts (~ 400µm in diameter) within commercially available polycarbonate PCR chips by multi-step ultraviolet (UV, 365nm) exposure. We optimized this photoimmobilization for thermal cycles of PCR as well. Acrylated forward primers incorporated in polyethylene glycol diacrylate (PEGDA) posts played a crucial role to confine fluorescent signal of cDNA amplification within the PEGDA hydrogel. To demonstrate the potential of our platform, we successfully verified multiplex detection of five miRNAs, which were reported to be highly correlated with AD, from a complex buffer of human plasma.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hydrogel micropost-based multiplex qPCR is reported for detection of miRNAs. </LI> <LI> Multi-step UV-exposure allows for immobilization of PEGDA microposts in PCR chips. </LI> <LI> Hydrogel-based qPCR results in the significant elimination of non-specific binding. </LI> <LI> 5-plex detection of miRNAs is presented with excellent specificity & selectivity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

WHAT DO ACQUIRING FIRMS DO WITH ACQUIRED KNOWLEDGE? THE IMPLICATION OF EXPLOITATION AND EXPLORATION FOR KNOWLEDGE LEVERAGE BEHAVIORS IN TECHNOLOGY ACQUISITIONS

Seungho Choi,Gerry McNamara 한국인사ㆍ조직학회 2013 한국인사ㆍ조직학회 발표논문집 Vol.2013 No.1

Obtaining knowledge through acquisitions is an important avenue with which firms can build a competitive advantage. However, to fully exploit the value associated with technology acquisitions, acquiring firms must effectively leverage knowledge acquired from these acquisitions. This study examines what firms do with acquired knowledge and how they create values by utilizing acquired knowledge in post acquisition. In particular, this paper identifies two distinct types of knowledge leverage behaviors by acquiring firms, knowledge integration and knowledge detachment, and it investigates how the previous innovation patterns of acquiring firms (exploitation vs. exploration) influence the modes of knowledge leverage behaviors in post acquisition. We find that exploration of acquiring firms tend to separate acquired knowledge of target firms from their prior knowledge so as to generate innovation in post acquisition. In addition, this paper finds that knowledge relatedness between acquiring and target firms moderates the relationship between previous innovation pattern of acquiring firms and their knowledge leverage mode.

A novel autophagy inducer, AS777, ameliorates liver fibrosis via suppressing liver inflammation

Seungho Choi,Min Woo Kim,Pasupathi Sundaramoorthy,Hyun-jin Jung,Ju-Hee Kang,Kwang Won Jeong,Hwan Mook Kim,Gyoonhee Han,Jung Ju Kim,Seong Won Song,Hye Jeong Shin,Seung Hyun Oh 한국실험동물학회 2019 한국실험동물학회 학술발표대회 논문집 Vol.2019 No.1

A novel STAT3 inhibitor, STX-0119, attenuates liver fibrosis in mice via inhibition of hepatic stellate cell activation

Seungho Choi,Ju-Hee Kang,Hyun Jin Jung,Yeong-Su Jang,Chang-Yong Lee,Dong Yun Shin,Yeo Sung Yoon,Seung Hyun Oh 한국실험동물학회 2018 한국실험동물학회 학술발표대회 논문집 Vol.2018 No.1

Profiling of testis-specific or testis-predominant genes expressed in mouse male germ cell lines GC-1 and GC-2

Choi Seungho,Hong Seong Hyeon,Han Gwidong,Cho Chunghee 한국유전학회 2024 Genes & Genomics Vol.46 No.3

Background Spermatogenesis is a tightly organized process that utilizes an intrinsic genetic program composed of germ cell-specific genes. Although mouse germ cell-related cell lines are available, few germ cell-specific genes have been comprehensively identified in such cell lines. Objective We aimed to profile gene expression in the male mouse germ cell-related cell lines, GC-1 and GC-2, characterize their transcriptomic nature, and identify potential testis- or germ cell-specific or -predominant genes expressed in these cell lines. Methods We performed profiling analysis of genes transcribed in the mouse germ cell-related cell lines, GC-1 and GC-2, using our previous microarray data together with public transcriptome information. We analyzed the expression of a number of the cell line genes predicted to be preferentially expressed in testis by RT-PCR. Results We found that most testis-specific or -predominant mRNAs are not expressed in GC-1 and GC-2 cells, implying that these cell lines have lost their testis- or germ cell-specific genetic characteristics. RT-PCR analysis of genes predicted to be expressed in the cell lines with preferential testicular expression showed the testis-specific or -predominant expression of nine genes and verified four of them as being expressed in the germ cell lines. Among them, only cyclin-dependent kinase inhibitor 3 genes (Cdkn3) showed testis and germ cell specificity. Conclusion Our study provides extensive transcriptomic information to shed light on the limited testicular characteristics of the mouse male germ cell-derived cell lines, GC-1 and GC-2, and offers a list of germ cell line genes with testicular preference. Background Spermatogenesis is a tightly organized process that utilizes an intrinsic genetic program composed of germ cell-specific genes. Although mouse germ cell-related cell lines are available, few germ cell-specific genes have been comprehensively identified in such cell lines. Objective We aimed to profile gene expression in the male mouse germ cell-related cell lines, GC-1 and GC-2, characterize their transcriptomic nature, and identify potential testis- or germ cell-specific or -predominant genes expressed in these cell lines. Methods We performed profiling analysis of genes transcribed in the mouse germ cell-related cell lines, GC-1 and GC-2, using our previous microarray data together with public transcriptome information. We analyzed the expression of a number of the cell line genes predicted to be preferentially expressed in testis by RT-PCR. Results We found that most testis-specific or -predominant mRNAs are not expressed in GC-1 and GC-2 cells, implying that these cell lines have lost their testis- or germ cell-specific genetic characteristics. RT-PCR analysis of genes predicted to be expressed in the cell lines with preferential testicular expression showed the testis-specific or -predominant expression of nine genes and verified four of them as being expressed in the germ cell lines. Among them, only cyclin-dependent kinase inhibitor 3 genes (Cdkn3) showed testis and germ cell specificity. Conclusion Our study provides extensive transcriptomic information to shed light on the limited testicular characteristics of the mouse male germ cell-derived cell lines, GC-1 and GC-2, and offers a list of germ cell line genes with testicular preference.

KNOWLEDGE LEVERAGE BEHAVIORS IN TECHNOLOGY ACQUISITIONS

Seungho Choi,Gerry McNamara 한국전략경영학회 2013 한국전략경영학회 학술대회발표논문집 Vol.2013 No.11

Obtaining knowledge through acquisitions is an important avenue with which firms can build a competitive advantage. However, to fully capture the value associated with acquisitions, acquiring firms must effectively leverage knowledge acquired from these acquisitions. This paper distinguishes two distinct types of knowledge leverage behaviors of acquiring firms by considering whether acquiring firms use their prior knowledge as inputs for post acquisition innovation: integrated knowledge leverage and independent knowledge leverage. This paper examines how the innovation patterns of acquiring firms before acquisitions (exploitation and exploration) influence these two modes of knowledge leverage behaviors in post acquisition processes. We find that explorative acquiring firms are more likely to pursue independent knowledge leverage that enables them reinvent and extend themselves in a new technology direction. In addition, knowledge similarity between acquiring and target firms moderates the relationship between previous innovation pattern of acquiring firms and their knowledge leverage mode. This study enhances our understanding about how acquiring firms create value by utilizing acquired knowledge following an acquisition.

Smart Lighting Control and Systematic Photovoltaic Monitoring Service UI/UX Design

Seungho Choi(최승호) 한국디자인학회 2019 한국디자인학회 국제초대전도록 Vol.2019 No.11

Investigating Ten-Finger Text Entry on Tablet PCs

Seungho Choi,Kyeongjin Park,Kyungdoh Kim 대한인간공학회 2017 大韓人間工學會誌 Vol.36 No.5

Objective: The aim of this study is to investigate the performance and usability of ten-finger text entry on Tablet PCs. Background: Generally a soft keyboard is used on Tablet PCs. However, the soft keyboard"s performance is usually worse than physical keyboard"s performance. In this study, we proposed a modified keyboard for tablet PCs to improve the performance of ten-finger text entry and evaluated the performance and subjective ratings of the keyboard. Method: The modified soft keyboard that is suggested in this study was compared with current Google and Samsung soft keyboards on Tablet PCs. Results: The three keyboards were not significantly different in terms of typing speed, error rate, and mental workload and showed bad performance. Also, the subjective ratings were not shown positively. Conclusion: Based on our results, ten-finger text entry using soft keyboards on Tablet PCs seems to be very difficult. However, we need to research the possibility continuously since ten-finger text entry can improve typing speed. Application: Our study can be a starting point of research that explores ten-finger text entry on Tablet PCs. The new soft keyboard design can be one of the soft keyboard alternatives. However, the key factors to improve the performance and usability of the soft keyboard will not be "key size" or "convenience to typing special characters or numbers", but other factors (e.g., "tactile feedback").

Ninjurin1 plays a crucial role in pulmonary fibrosis by promoting interaction between macrophages and alveolar epithelial cells

Seungho Choi,Jong Kyu Woo,Yeong-Su Jang,Ju-Hee Kang,Jong-Ik Hwang,Je-Kyung Seong,Yeo Sung Yoon,Seung Hyun Oh 한국실험동물학회 2018 한국실험동물학회 학술발표대회 논문집 Vol.2018 No.7