Effects of Oxidation and Nitridation Temperatures on Electrical Properties of Sputtered Zr Thin Film Based on Si in N2O Ambient

Yew Hoong Wong,Kuan Yew Cheong 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.1

The effects of oxidation and nitridation temperatures (500-1100°C) on metal-oxide-semiconductor charac-teristics of sputtered Zr thin film on Si in N2O ambient have been systematically investigated. The sample being oxidized and nitrided at 700°C has demonstrated the highest effective dielectric constant of 21.82 and electrical breakdown field of 13.6 MV cm−1at a current density of 10−6A cm−2. This is attributed to the lowest effective oxide charge, interface-trap density, and total interface-trap density of the oxide and the highest barrier height of conduction band offset between the oxide and semiconductor when compared with others.

Update on Phosphorylation-Mediated Brassinosteroid Signaling Pathways

Yew Lee(이유),Soo Hwan Kim(김수환) 한국생명과학회 2012 생명과학회지 Vol.22 No.3

단백질 인산화는 세포의 활동을 조절하는 보편적인 과정이다. 브라시노스테로이드(brassinostreoid)에 의해 매개되는 신호전달은 브라시노스테로이드에 의해 활성화된 세포막상의 protein kinase 로부터 인산화되어 있는 전사 인자들을 탈인산화하는 연속적인 인산화/탈인산화 과정이다. 브라시노스테로이드에 의해 매개되는 신호전달의 연구는 인산화에 관여하는 kinase 기질상의 아미노산을 밝히고, 그와 관련된 돌연변이체의 표현형을 알아봄으로써 급속하게 발전하였다. BRI1과 BAK1의 자기인산화(autophosphorylation), 상호인산화(transphosphorylation), 타이로신 인산화(tyrosine phosphorylation)를 밝힘으로써 그들의 조절작용을 식물의 생리학적, 발생학적 과정을 더 이해할 수 있는 장이 열렸다. 브라시노스테로이드에 의한 인산화는 수용체에 의해 매개되는 세포 내 함입(endocytosis)과 그에 뒤따르는 수용체의 파괴현상에서도 볼 수 있다. 인산화/탈인산화 과정에 관련하여 브라시 노스테로이드에 의해 매개되는 신호전달은 더 연구할 여지가 많이 남아 있다. 이 총설은 단백질의 인산화/탈인산화 과정을 통한 브라시노스테로이드의 신호전달 연구의 최근 상황을 기술하였다. Protein phosphorylation is a universal mechanism that regulates cellular activities. The brassinosteroid (BR) signal transduction pathway is a relay of phosphorylation and dephosphorylation cascades. It starts with the BR-induced activation of the membrane receptor kinase brassinosteroid insensitive 1 (BRI1), resulting in the dephosphorylation of transcription factors such as BZR1/BES2 and BZR2/BES1 followed by BR-induced gene expression. Brassinosteroid signal transduction research has progressed rapidly by identifying the phosphorylation/dephosphorylation site(s) of the BR-regulated kinase and phosphatase substrates with a simultaneous pursuit of mutant phenotypes. Autophosphorylation, transphosphorylation, and serine/threonine and tyrosine phosphorylation of the receptor protein kinases BRI1 and BRI1-associated kinase (BAK1) have increased the understanding of the regulatory role of those kinases during physiological and developmental processes in plants. The phosphorylation event initiated by BR is also found in the regulation of receptor-mediated endocytosis and the subsequent degradation of the receptor. However, the basic molecular links of the BR signal transduction pathway are not well understood regarding this phosphorylation/dephosphorylation event. This review summarizes the current state of BR signal transduction research to uncover the phosphorylation/ dephosphorylation networks and suggests directions for future research on steroid signal transduction to gain a more comprehensive understanding of the process.

Poster Session : Plant Genetics ; An Arabidopsis RanGTP-binding protein, AtRanBP1c, is a coactivator of Ran GTPase activating protein and requires C-terminus for its cytoplasmic Localization

( Yew Lee ),( Stanley J. Roux ),( Soo Hwan Kim ) 생화학분자생물학회 2007 생화학분자생물학회 춘계학술발표논문집 Vol.2007 No.-

Base Stocks : A Formulator's Market Place

Yew Chin Law 한국트라이볼로지학회 2007 Lubricants SYMPOSIUM Vol.2007 No.9

Hazardless Biomedical Sensing Data Transmission Using VLC

Yew-Kiat Cheong,Xiao-Wei Ng,Wan-Young Chung IEEE 2013 IEEE SENSORS JOURNAL Vol.13 No.9

<P>The implementation of radio-frequency communication technologies in biomedical or healthcare applications involves multiple issues such as interference with precision medical instruments and human health hazard because of electromagnetic waves. A novel visible light communication technology for transmitting and monitoring biomedical data is presented. White beam light emitting diodes are used as optical information emitters for efficiently transmitting biomedical data such as patient information text and wavelike body sensor signals. ON/OFF keying modulation is used to modulate the data onto the visible light beam, and a high-speed p-i-n photo-detector is employed at the receiver. Experimental analysis of the data collected using this system demonstrates the effectiveness of the proposed method.</P>

SMC Reliable Design for T-S Model-Based Systems

Yew-Wen Liang,Sheng-Dong Xu,Der-Cherng Liaw,Cheng-Chang Chen,Li-Wei Ting 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

This paper studies the robust reliable control issues based on the Takagi-Sugeno (T-S) fuzzy system modeling method and the sliding mode control (SMC) technique. The combined scheme is shown to have the merits of both approaches. It not only alleviates the on-line computational burden by using the T-S fuzzy system model to approximate the original nonlinear one (since most of the system parameters of the T-S model can be computed off-line) but it also preserves the advantages of rapid response and robustness of the SMC schemes. Moreover, the combined scheme does not require on-line computation of any nonlinear term of the original dynamics and the increase in the partition number of the region of premise variables does not create extra on-line computational burdens for the scheme. Under the design, the control mission can continue safely without prompt external support even when the susceptible actuators fail to operate. The proposed analytical results are also applied to the attitude control of a spacecraft. Simulation results demonstrate the benefits of the proposed scheme.

Intraoperative Motor Evoked Potential Improvement in Cervical Spondylotic Myelopathy: Comparison of Cortical Stimulation Parameters

Yew Long Lo,Lisa Zhu,Reuben C Soh,Chang Ming Guo 대한신경과학회 2020 Journal of Clinical Neurology Vol.16 No.1

Background and Purpose Intraoperative monitoring of the motor pathways is a routine procedure for ensuring the integrity of descending motor tracts during spinal surgery. Intraoperative motor evoked potential improvement (MEPI) may be associated with a better postsurgical outcome in cervical spondylotic myelopathy (CSM). To compare the efficacy of two cortical stimulation parameters in eliciting MEPI intraoperatively during CSM surgery. Methods We studied 69 patients who underwent decompression surgery for CSM over a 9-month period using either 5 (Group 1) or 9 (Group 2) stimuli. MEPI was defined as the increase in the amplitude of MEPs from baseline at the end of CSM surgery just prior to skin closure. Results An MEPI of 100% from baseline was observed in 10 patients (53%) in Group 1 and 36 patients (72%) in Group 2. Comparisons of the baseline mean MEP amplitudes of muscles bilaterally between Groups 1 and 2 did not reveal any significant differences. Supramaximal stimulation showed that a significantly higher mean intensity was required for Group 1 than for Group 2. Conclusions MEPI is observed in a much larger proportion of cervical decompression surgery cases than previously thought. Intraoperative MEPI with longer-train cortical stimulation may reflect adequacy of decompression and provide additional guidance for the surgical procedure.

New Antitubercular Drugs : Where Do We Go from Here?

Yew, wing Wai,Chau, Chi Hung Medical Publications Korea 1997 Medical Progress Vol.19 No.10

A Review of Sirtuin Inhibitors in Therapeutics, Pharmaceutics, and Plant Research

Yew Lee(이유) 한국생명과학회 2020 생명과학회지 Vol.30 No.1

서투인 억제제는 유형 III 히스톤 데아세틸라제(HDAC)인 서투인을 억제하는 화합물이며, 약제학적 및 치료학적 가치를 갖는다. 합성 서투인 억제제는 효모 S. cerevisiae 에서 세포-기반 스크린을 사용하여 발견되었고 특성화 되었으며 서투인의 기능과 관련된 노화, 발암 및 당뇨병을 연구하는데 사용되었다. 의학 분야에서 합성 서투인 억제제는 보다 강력한 효능과 특이성을 얻기 위해 개발되어 왔다. 니코틴아미드 및 티오아세틸리신 함유 화합물, β-나프톨 함유화합물, 인돌 유도체. 수마린, 테노빈 및 그 유사체가 개발 되었다. 서투인 억제제는 식물 발달에 영향을 미치는 것으로 밝혀졌으며 식물의 화학적 유전학에 사용되었다. 그러나, 시르티놀-내성 돌연변이 체는 알데히드 옥시다제에 대한 몰리브돕테린 보조인자의 생합성 유전자에 돌연변이가 있었다. 일부 천연 플라보노이드, 카테킨 유도체 및 퀴르세틴 유도체는 서투인 억제제로서 작용하며 치료 목적을 위한 보다 강력한 억제제를 찾기위해 연구 되고 있다. 이 리뷰에서, 서투인을 소개하면서 치료제에서 개발된 서투인 억제제를 소개한다. 서투인 억제제인 서티놀은 식물에서 화학적 유전학에 예기치 않게 사용되었습니다. 보다 강력하고 선택적인 서투인 억제제가 치료제에서 개발되어야 하고, 약학에서 개발된 다른 서투인 억제제는 식물에서 보다 진정한 서투인을 찾기위해 사용되어야 한다. Sirtuin inhibitors are pharmaceutically and therapeutically valuable compounds that inhibit sirtuin, a type III histone deacetylase. Synthetic sirtuin inhibitors were discovered and characterized using cell-based screens in yeast (Saccharomyces cerevisiae) and have been used in the study of aging, carcinogenesis, and diabetes, all of which are related to sirtuin function. For medical applications, synthetic inhibitors have been further developed for increased potency and specificity, including compounds containing nicotinamide, thioacetyl lysine, β-naphthol, and indole derivatives. Suramin, tenovin, and their analogues were developed as a result. Sirtuin inhibitors were found to affect organic development and have been used to genetically modify plants, although a sirtinol-resistant mutation in the biosynthesis of a molybdopterin cofactor for an aldehyde oxidase has been identified. Some natural flavonoids, and catechin and quercetin derivatives also act as sirtuin inhibitors have been studied to identify a more potent inhibitor for therapeutic purposes. In this review, sirtuin is introduced and the therapeutic inhibitors that have been developed are presented, particularly sirtinol which has been used for genetic modification in plants though it was not designed to be so. Sirtuin inhibitors with greater potency and selectivity are required and those developed in pharmaceutics should be used in plant research to identify more authentic sirtuins in plants.

Cell Type Identity in Arabidopsis Roots Is Altered by Both Ascorbic Acid-Induced Changes in the Redox Environment and the Resultant Endogenous Auxin Response

( Yew Lee ),( Myoung Won Kim ),( Soo Hwan Kim ) 한국식물학회 2007 Journal of Plant Biology Vol.50 No.4

Redox plays a critical role in controlling many cellular processes of plant growth and development. To understand the effect of changes in redox on cell-type determination in the root meristem, we examined the influence of a strong reducing agent - ascorbic acid (AA) - on both the expression patterns of several cell type-specific promoters and the endogenous auxin sensitivity of auxin-responsive DR5::GUS transgenic plants. AA treatment altered the regular expression of columella-specific markers. Moreover, when the same treatment was applied to the DR5::GUS lines, normal expression of the GUS reporter was completely abolished in the auxin maximum, while exogenous auxin restored AA-driven depletion of that maximum. Interestingly, the level of DHA (dehydroascorbate, an oxidized form of AA) in the AA-treated roots was greatly increased. This indicates that changes in cell-type specificity and the sensitivity to endogenous auxin may result from an increase in the cellular DHA that is metabolized from exogenously supplied AA. Therefore, we propose that redox changes in the root meristem alter auxin homeostasis, perhaps causing a change in cell types within the root meristem.