• 제목/요약/키워드: Chemistry factor

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다이사이클로펜타다이에닐 비스페놀 시아네이트 에스터와 폴리페닐렌에테르를 이용한 저유전손실 고분자 기판 소재 (Polymer Substrate Materials with Low Dielectric Loss Using Dicyclopentadienyl Bisphenol Cyanate Ester and Polyphenylene Ether)

  • 김동국;박성대;이우성;유명재;박세훈;임진규;경진범
    • 폴리머
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    • 제31권6호
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    • pp.474-478
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    • 2007
  • 다이사이클로펜타다이에닐 비스페놀 시아네이트 에스터 올리고머와 열가소성 수지인 폴리페닐렌에테르(PFE)를 복합체화함으로써 유전손실이 적은 고분자 기판소재를 제작하였다. 올리고머와 촉매의 경화반응을 분석하여 최적 촉매첨가량을 Zn 0.02 phr로 선정하고 이를 복합체 제작에 적용하였다. 올리고머와 PPE의 함량비를 변화시키며 제작된 복합체의 동박 박리 강도, gel content 등을 측정하였으며, GHz 대역에서의 유전율과 유전손실을 평가하였다. PPE의 함량은 박리 강도 및 유전특성에 큰 영향을 주었으나, 촉매의 함량에 따라서는 유전특성에 큰 차이가 없었다. 실험결과 박리 강도가 1 kN/m 이상이고, 1 GHz에서 유전손실이 0.004로 낮은 고분자 복합체 라미네이트를 얻을 수 있었다.

NMR Study of Consensus DNA-binding Site for Arabidopsis thaliana Class I Transcription Factor AtTCP1

  • Choi, Yong-Geun;Kim, Hee-Eun;Lee, Joon-Hwa
    • 한국자기공명학회논문지
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    • 제17권2호
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    • pp.76-80
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    • 2013
  • The TCP domain is a DNA-binding domain present in plant transcription factors and has a similar structural feature to the bHTH motif of eukaryotic transcription factors. The imino proton exchange study has been performed for the DNA duplex containing the consensus DNA-binding site for the AtTCP11 transcription factor. The first two base pairs in the consensus 5'-GTGGG-3' sequence are relatively very unstable but lead to greater stabilization of the neighboring two G C base pairs. These unique dynamic features of the five base pairs in the consensus DNA sequence might play crucial roles in the effective DNA binding of the AtTCP11 protein.

Indoor exposure to hazardous air pollutants and volatile organic compounds in low-income houses in Lagos, Nigeria

  • Luqmon, Azeez;Musa, Olaogun;Mariam, Adeoye;Abdulazeez, Lawal;Babatunde, Agbaogun;Ibrahim, Abdulsalami;Adija, Majolagbe
    • Advances in environmental research
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    • 제1권4호
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    • pp.277-288
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    • 2012
  • This study investigated exposure to air pollutants in rooms in low-income houses at Shomolu (R1), Mafoluku (R2) and Mushin (R3) in Lagos state. The concentrations of most measured exceeded limits of Illinois Department of Public Health (IDPH) for indoor air quality. Air quality index (AQI) in rooms studied was unhealthy for sensitive people in terms of CO, unhealthy in terms of $SO_2$ and very unhealthy in terms of $NO_2$ while moderate air quality was obtained in terms of $PM_{10}$ in most rooms. High concentrations of carbontetrachloride, formaldehyde and xylene measured could have been responsible for some of the health complaints of the occupants. Factor analysis shows that cooking with kerosene, use of gasoline generator and insecticide were the major contributors to indoor air pollution in these rooms. Therefore, there is need to urgently tackle poverty as all affected by these pollutants were poor who live in substandard houses without kitchens.

A Novel Anticoagulant Protein from Scapharca broughtonii

  • Jung, Won-Kyo;Je, Jae-Young;Kim, Hee-Ju;Kim, Se-Kwon
    • BMB Reports
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    • 제35권2호
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    • pp.199-205
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    • 2002
  • An anticoagulant protein was purified from the edible portion of a blood ark shell, Scapharca broughtonii, by ammonium sulfate precipitation and column chromatography on DEAE-Sephadex A-50, Sephadex G-75, DEAE-Sephacel, and Biogel P-l00. In vitro assays with human plasma, the anticoagulant from 'S. broughtonii, prolonged the activated partial thromboplastin time (APTT) and inhibited the factor LX in the intrinsic pathway of the blood coagulation cascade. But, the fibrin plate assay did not show that the anticoagulant is a fibrinolytic protease. The molecular mass of the purified S. broughtonii anticoagulant was measured to be about 26.0kDa by gel filtration on a Sephadex G-75 column and SDS-PAGE under denaturing conditions. The optimum activity in the APTT assay was exhibited at pH 7.0-7.5 and $40-45^{\circ}C$ in the presence of $Ca^{2+}$.

Improvement of output coupling efficiency of organic light emitting device by using porous anodic alumina

  • Lee, Hyung-Sup;Choi, Ji-Young;Gao, Xinwei;Kim, Seong-Su;Lee, K.W.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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    • pp.625-628
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    • 2004
  • Porous anodic alumina(PAA) which has arrays of nano size holes, was incorporated into organic light emitting devices. Porous anodic alumina on glass scattered the light generated from emitting layer and was decreased the waveguiding modes within the glass. An increase in the device coupling-out factor for the scattering structure is demonstrated.

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Evaluation of Erosivity Index (EI) in Calculation of R Factor for the RUSLE

  • Kim, Hye-Jin;Song, Jin-A;Lim, You-Jin;Chung, Doug-Young
    • 한국토양비료학회지
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    • 제45권1호
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    • pp.112-117
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    • 2012
  • The Revised Universal Soil Loss Equation (RUSLE) is a revision of the Universal Soil Loss Equation (USLE). However, changes for each factor of the USLE have been made in RUSLE which can be used to compute soil loss on areas only where significant overland flow occurs. RUSLE which requires standardized methods to satisfy new data requirements estimates soil movement at a particular site by utilizing the same factorial approach employed by the USLE. The rainfall erosivity in the RUSLE expressed through the R-factor to quantify the effect of raindrop impact and to reflect the amount and rate of runoff likely is associated with the rain. Calculating the R-factor value in the RUSLE equation to predict the related soil loss may be possible to analyse the variability of rainfall erosivity with long time-series of concerned rainfall data. However, daily time step models cannot return proper estimates when run on other specific rainfall patters such as storm and daily cumulative precipitation. Therefore, it is desirable that cross-checking is carried out amongst different time-aggregations typical rainfall event may cause error in estimating the potential soil loss in definite conditions.

Screening of Peptides Bound to Anthrax Protective Antigen by Phage Display

  • Kim, Joung-Mok;Park, Hye-Yeon;Choi, Kyoung-Jae;Jung, Hoe-Il;Han, Sung-Hwan;Lee, Jae-Seong;Park, Joon-Shik;Yoon, Moon-Young
    • Journal of Microbiology and Biotechnology
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    • 제16권11호
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    • pp.1784-1790
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    • 2006
  • Bacillus anthracis is a causative agent of anthrax. Anthrax toxins are composed of a protective antigen (PA), lethal factor (LF), and edema factor (EF), in which the PA is a central mediator for the delivery of the two enzymatic moieties LF and EF. Therefore, the PA has been an attractive target in the prevention and vaccinization for anthrax toxin. Recently, it has been reported that the molecule consisting of multiple copies of PA-binding peptide, covalently linked to a flexible polymer backbone, blocked intoxification of anthrax toxin in an animal model. In the present study, we have screened novel diverse peptides that bind to PA with a high affinity (picomolar range) from an M13 peptide display library and characterized the binding regions of the peptides. Our works provide a basis to develop novel potent inhibitors or diagnostic probes with a diverse polyvalence.

In vitro Interaction of Recombinantly Expressed Kringle 5 (rK5) with Ras Guanine Nucleotide Dissociation Stimulator-like Factor (Rgl2)

  • Lee, Jung-Whoi;Kim, Sun-Hee;Park, Yong-Sung;Woo, Je-Wan;Lim, Dong-Yeol;Lee, Kyung-Hee
    • Bulletin of the Korean Chemical Society
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    • 제25권12호
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    • pp.1863-1868
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    • 2004
  • Kringle 5 (K5), located outside of angiostain (K1-4) in human plasminogen, displays more potent antiangiogenic activity on endothelial cell proliferation than angiostatin itself. Using a yeast two-hybrid system in vivo, we have recently identified Rgl2 (guanine nucleotide dissociation stimulator (RalGDS)-like factor 2) as a binding protein of human K5. In order to confirm in vitro protein interaction between K5 and Rgl2, we developed bacterial recombinant expression systems for them. K5 and Rgl2 proteins were expressed in high yields and purified into pure forms with His tags and GST fusion, respectively. GST-pull down experiments clearly demonstrated that K5 interacts specifically with Rgl2 in vitro. These results indicate that Rgl2 functions as a receptor protein for K5 in vitro as well as in vivo, leading to anti-angiogenesis through regulating Ras signaling pathways.

Yeast내에서 MEK1 융합 단백질 발현 및 Lethal Factor 활성 검증 (Expression of MEK1 Fusion Protein in Yeast for Developing Cell Based Assay System, a Major Substrate of LeTx)

  • 황혜현;김정목;최경재;박해철;한성환;정회일;구본성;박준식;윤문영
    • 미생물학회지
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    • 제42권3호
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    • pp.195-198
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    • 2006
  • Anthrax lethal toxin은 탄저병의 치사원인이 되는 독소이며, Lethal toxin은 두 종류의 단백질 PA (Protective antigen)과 LF (lethal factor)로 구성되어 진다. PA는 세포표면의 수용체와 결합하여 LF를 세포질 안으로 이동시켜 주는 역할을 한다. LF는 금속 이온$(Zn^{2+})$ 의존적 단백질 가수분해 효소로써 MKKs[MAPK (mitogen-activated protein kinase) kinases] 집단 단백질의 아미노 말단 부분을 절단하여 대상 세포를 죽음으로 유도하는 것으로 알려져 있다. 본 연구에서는 LF에 대한 특성 분석 및 억제제 개발에 과한 연구를 위해 cell-based high-throughtput screens 개발에 선행되어야 하는 기초 자료를 마련하는데 그 목적이 있다. 이를 위하여 LF의 절단 대상이 되는 기질이 MEK1을 yeast내에서 동시 발현시켜 LF의 활성을 검증하였다. 먼저 효모(Saccharomyces cerevisiae)를 숙주로 하여 LF의 기질인 MEK1 발현 vector를 구축하였고, 구축된 발현 system을 기본을 LF 활성을 검증하고자 yeast에 형질전환하여 plasmid의 안전성 및 MEK1 유전자의 발현 및 LF에 의한 MEK1 아미노말단의 절단 부위를 확인하였다. 본 연구는 세포내 검증 system 도입의 기초적 자료를 제공하였으며, yeast내의 MEK1 발현은 탄저병의 저해제 선별 및 활성 측정 검증을 생체에서 고효율적이며, 안정적으로 할 수 있다는 가능성을 나타냈다.