• BMB Reports
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• 제30권2호
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• pp.113-118
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• 1997

Aspartase from Hafnia alvei was inactivated by N-ethylmaleimide (NEM) and 5,5' -Dithiobis-(2-znitrobenzoic acid) (DTNB) following pseudo-first order kinetics. Their apparent reaction orders were 0.83 and 0.50 for NEM and DTNB modifications, respectively, indicating that inactivation was due to a sulfhydryl group in the active site of aspartase and participation of the sulfhydryl group in an essential step in the catalytic reaction. When aspartase was modified by DTNB, the enzyme activity was restored by dithiothreitol treatment, indicating that cysteine residuetsl islarel possibly at or near the active site. The pH-dependence of the inactivation rate by NEM suggested that an amino acid residue having pK value of 8.3 was involved in the inactivation. When aspartase was incubated with NEM and L-aspartate together, L-aspartate markedly protected the enzyme from inactivation by NEM, but the other reagents used did not.

• 약학회지
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• 제34권6호
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• pp.434-438
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• 1990

The methanolic extract of the root-bark of Morus alba L.(Mulberry tree) has the potent antibacterial activity against Streptococcus mutans. Its active component was identified to be sanggenon C. The active component had stronger anti-bacterial activity than berberine, having minimum inhibitory concentration(MIC) of $25\;{\mu}g/ml$. Moreover, the inhibitory effect of this component on the cellular adherence of Streptococcus mutans to glass surfaces also was more remarkable than that of berberine in the presence of glucosyltransferase(GTase) and sucrose in vitro. These results indicate that sanggenon C may play an important role in inhibiting plaque formation and caries incidence.

• 한국응용과학기술학회지
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• 제7권1호
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• pp.49-62
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• 1990

In order to synthesize N,N-di-(polyoxyethylene) perfluoroacyl amines and the surface active monoperfluoroacyl aza crown ethers, it is performed as follow. Six of N,N-di(polyoxyethylene) perfluoro acyl amines were synthesized from perfluoroalkanoic acids with ethanol followed by oxyethylation with triethylene glycol mono chloride or tetra ethylene glycol mono chloride and six of N-perfluor acyl monoaza crown ethers by cyclization of corresponding N,N-di(polyoxy ethylene} perfluoro acyl amines with p-toluene suflonic chloride-NaOH/dioxane, p-toluene sulfonyl chloride KOH/dioxane and benzene sulfonic chloride-KOH/dioxane systems.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.927-930
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• 2009

We studied the solution processes of IGZO thin films and investigated the electrical characteristics of thin film transistor (TFT) with sol-gel processed InGaZn-oxide active semiconductor layer. In particular, the effect of composition variation and post annealing temperature were studied by using solutions having various metal cation ratios to optimize transistor performance.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1571-1572
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• 2009

Polymer solar cells were fabricated with gravure printing process and the effect of thermal annealing of gravure printed organic layer was investigated. The layer structure of polymer solar cells is glass / ITO / hole transfer layer / active layer / Al structure was fabricated. For the active layer, 1:1 ratio of poly-3-hexylthiophene (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) mixture was applied. The P3HT/PCBM blend was gravure printed onto the substrates. The effect of thermal annealing was investigated by changing annealing time and the number of printing. Maximum 3.6% of power conversion efficiency was achieved with gravure printing of organic layer and thermal annealing in this work.

• Korean Chemical Engineering Research
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• 제49권1호
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• pp.10-14
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• 2011

철 이온 교환방법에 의해 메조기공을 갖는 활성탄소 섬유(ACF)를 제조하고, 이를 사용하여 전기 이중층 커패시터(EDLC)의 전극소재 성능을 조사하였다. 질산처리에 의해 제조된 메조기공 ACF는 비표면적이 1,249, 664 $m^2/g$이고, 메조 기공 분율이 70.6-81.3%이고, 평균 기공크기는 약 2.78~4.14 nm이다. 질산처리시간이 짧을수록 비표면적이 크고 메조 기공이 적게 발달됨을 알 수 있었다. 전기이중층 커패시터의 성능을 조사하기 위해서, 메조기공 ACF, 도전제, 바인더를 사용하여 단위 셀을 제조하였으며, 유기 전해질을 사용하였다. 2시간 질산으로 처리된 ACF의 비 축전양은 0.47 $F/cm^2$이고, 20회 충.방전 테스트에서 안정된 실험결과를 얻을 수 있었다. EDLC의 전기화학적 성능은 ACF 전극의 비표면적에 크게 영향을 받으며 메조기공은 전하의 확산저항을 감소시키는 것을 알 수 있었다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권3호
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• pp.180-185
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• 2005

Cytosine deaminase (cytosine aminohydrolase, EC 3.5.4.1) stoichiometrically catalyzes the hydrolytic deamination of cytosine and 5-fluorocytosine to uracil and 5-fluorouracil, respectively. Amino acid residues located in or near the active sites of the intracellular cytosine deaminase from chromobacterium violaceum YK 391 were identified by chemical modification studies. The enzymic activity was completely inhibited by chemical modifiers, such as 1mM NBS, chloramine-T, $\rho-CMB,\;\rho-HMB$ and iodine, and was strongly inhibited by 1mM PMSF and pyridoxal 5'-phosphate. This chemical deactivation of the enzymic activity was reversed by a high concentration of cytosine. Furthermore, the deactivation of the enzymic activity by $\rho-CMB$ was also reversed by 1mM cysteine-HCI, DTT and 2-mercaptoethanol. These results suggested that cysteine, tryptophan and methionine residues might be located in or near the active sites of the enzyme, while serine and lysine were indirectly involved in the enzymic activity. The intracellular cytosine deaminase from C violaceum YK 391 was assumed to be a thiol enzyme.

• Journal of Ginseng Research
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• 제42권3호
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• pp.334-342
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• 2018

Background: Panax notoginseng is a highly valued medicine and functional food, whose quality is considered to be influenced by the size, botanical parts, and growth environments. Methods: In this study, a HPLC method integrating fingerprinting and determination of multiconstituents by single reference standard was established and adopted to investigate the chemical profiles and active constituent contents of 215 notoginseng samples with different sizes, from different botanical parts and geographical regions. Results: Chemical differences among main root, branch root, and rotten root were not distinct, while rhizome and fibrous root could be discriminated from other parts. The notoginseng samples from Wenshan Autonomous Prefecture and cities nearby were similar, whereas samples from cities far away were not. The contents of major active constituents in main root did not correlate with the market price. Conclusion: This study provided comprehensive chemical evidence for the rational usage of different parts, sizes, and growth regions of notoginseng in practice.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1997년도 제12회 학술발표회 논문개요집
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• pp.43-44
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• 1997

We repport the effects of active nitrogens on the low-tempperature growth of GaN by a remote pplasma-enhanced metal-organic chemical vappor depposition method. the emission intensities of active nitrogens increase with fr ppower and nitrogen flow rate, but decrease with total reactor ppressure. Low-tempperature growth of GaN are greatly affected by the concentrations of active nitrogens and its concentrations are closely related with the emission intensities.

• Current Optics and Photonics
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• 제1권4호
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• pp.358-363
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• 2017

In this study, we present a detailed investigation of luminescence properties of a blue light-emitting diode using InGaN/GaN (indium component is 17.43%) multiple quantum wells as the active region grown on patterned sapphire substrate by low-pressure metal-organic chemical vapor deposition (MOCVD). High-resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), Raman scattering (RS) and photoluminescence (PL) measurements are employed to study the crystal quality, the threading dislocation density, surface morphology, residual strain existing in the active region and optical properties. We conclude that the crystalline quality and surface morphology can be greatly improved, the red-shift of peak wavelength is eliminated and the superior blue light LED can be obtained because the residual strain that existed in the active region can be relaxed when the LED is grown on patterned sapphire substrate (PSS). We discuss the mechanisms of growing on PSS to enhance the superior luminescence properties of blue light LED from the viewpoint of residual strain in the active region.