• 한국응용과학기술학회지
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• 제20권2호
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• pp.94-100
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• 2003

We studied electrochemical characteristics of Langmuir-Blodgett(LB) films by using cyclic voltammetry with a three-electrode system. An Ag/AgCl as a reference electrode, a platinum wire as a counter electrode and LB film-coated indium tin oxide(ITO) as a working electrode were used to study electrochemical characteristics at a various concentration of $NaClO_4$ solution. LB films were reduced from initial potential to -1350 mV, continuously oxidized to l650mV and returned to the initial point. The scan rate was l00mV/s. The monolayer surface morphology of the LB film have been measured by Atomic Force Microscope(AFM). As a result, We comfirmed that the microscopic properties of LB film by AFM showed the good orientation of momolayer molecules and the thickness of monolayer was 3.5-4.lnm. The cyclic voltammograms(CV) of the ITO-coated glass showed the peak potentials for the reduction-oxidation reation. LB films of 4-octyl-4'-(5-carboxypentamethyleneoxy) azobenzene(8A5H) / L-${\alpha}$-phosphayidyl choline, dilauroyl(DLPC) seemed to be irreversible process caused by only the oxidation current from the cyclic voltammogram. The current of oxidatation increased at cyclic voltammogram by increasing 8A5H density in LB films. The diffusivity(D) of LB films increased with increasing of a 8A5H amount and was inversely proportional to the concentration of $NaClO_4$ solution.

• KSBB Journal
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• 제8권4호
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• pp.382-389
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• 1993

초산이온이 대장균 성장을 저해하는 현상을 규명 하기 위해서 M9 배지, LB 배지를 사용해서 플라스 크, 발효조 배양을 수행하였다. 대장균의 초산 생성 은 높은 포도당 초기 농도, LB 배지와 같은 복합 배 지에서 활발하였고, 플라스크 배양과 같은 pH 조절 이 되지 않는 배양방법에셔는 초산의 생성에 따른 pH 감소에 따라 세포성장이 많이 저해되었다. 초산 을 외부에서 첨가하여 세포성장에 마치는 영향을 조 사하여 보았는데 LB 배지를 사용한 플라스크 배양 에서는 첨가된 초산의 농도가 2g/l 이상, M9 배지 를 사용한 플라스크 배양에서는 초산의 농도가 4g/l 이상, 그리고 M9 배지를 사용한 발효조 배양에 셔는 8g/l 이상에서 초산의 성장 저해효과가 나타 다. LB 한천 배지를 볕에 깐 LB 액체 배지의 플라스 크 배양을 수행하였다. LB 한천의 양이 증가함에 따라서 한천에서 포도당의 방출이 일어나 최종 대장 균 세포 O.D.가 증가하였다.

• Archives of Pharmacal Research
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• 제19권1호
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• pp.52-59
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• 1996

The in vitro activity of LB20304 was evaluated against clinical isolates and compared with those of Q-35, ciprofloxacin, sparfloxacin, lomefloxacin and ofloxacin. LB20304 demonstrated 16-to 64-fold more potent activity than ciprofloxacin against gram-positive bacteria. LB20304 inhibited 90% of the isolates of methicillin-susceptible Staphylococcus aureus(MSSA) at a concentration of $0.016\mug/ml\; (MIC_{90}). MIC_{90}$ values of LB20304 against methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible Staphylococcus epidermidis (MSSE), methicillin-resistant S. epidermidis (MRSE) and Streptococcus pneumoniae were $2\mug/ml,\; 0.016\mug/ml,\; 0.5\mug/ml \;and\; 0.031\mug/ml,$ respectively. LB20304 was also very active against gram-negative bacteria. Against Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Pseudomonas aeruginosa and Acinetobacter calcoaceticus, $MIC_{90}s of\; LB20304 were\; 0.031\mug/ml,\; 0.25\mug/ml,\; 2\mug/ml,\; 8\mug/ml\; and\; 0.5\mug/ml$, respectively. Its activity was comparable to that of ciprofloxacin but much better than those of Q-35, sparfloxacin, ofloxacin and lomefloxacin. LB20304 also exhibited the most potent acitvity among quinolones tested against laboratory standard strains, ofloxacin-resistant strains, .betha.-lactamase-producing strains and anaerobic strains. The inhibitory effect$ (IC_{50)$ of LB20304 on DNA gyrase from Micrococcus luteus, determined by the supercoiling assay, was 8-fold more potent than that of ciprofloxacin. LB20304 did not induce topoisomerase-associated DNA cleavage even at a concentration of 10 mg/ml, although ciprofloxacin induced DNA cleavage at a concentration of 1 mg/ml.

• 한국축산식품학회지
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• 제44권1호
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• pp.204-215
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• 2024

This study was designed to examine the effect of Lactilactobacillus curvatus LB-P9 on hair regeneration. The treatment of LB-P9 conditioned medium increased the proliferation of both hair follicle dermal papilla cells and hair germinal matrix cells (hGMCs). Moreover, the expression levels of hair growth factors such as vascular endothelial growth factor (VEGF) and fibroblast growth factor 7 were significantly elevated in hGMCs co-cultured with LB-P9. After time-synchronized depilation, mice were orally administered with either 4×10⁷ colony forming unit (CFU) of LB-P9 (low dose) or 4×10⁸ CFU of LB-P9 (high dose), once daily for 4 weeks. Compared with the vehicle (phosphate-buffered saline)-administrated group, the LB-P9-treated groups exhibited accelerated hair regrowth rate and enhanced hair thickness in a dose-dependent manner. Supporting this observation, both hair follicle numbers and the dermal thickness in skin tissues of the LB-P9-treated groups were increased, compared to those of the vehicle-treated group. These results might be explained by the increased level of β-catenin and number of hair follicle stem cells (CD34⁺ CD49f⁺ cells) in the skin tissues of mice administered with LB-P9, compared to the vehicle-treated mice. Also, increased serum levels of hair growth factors such as VEGF and insulin-like growth factor-1, and superoxide dismutase were found in the LB-P9-treated groups, compared to those of the vehicle-treated group. Taken together, these results might demonstrate that the oral administration of LB-P9 promotes hair regeneration by the enhancement of dermal papilla proliferation through the stimulation of hair growth factor production.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권7호
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• pp.508-513
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• 1999

The response properties of quartz crystal coated with stearic acid LB films to organic gases were investigated by measuring the shift of resonant frequency. Stearic acid was used as a sensing material and deposited on the surface of quartz crystal using the Langmuir-Blodgett(LB) method. The effect of temperature on the quartz crystal coated with stearic acid LB films was also investigated by Scanning Maxwell-stress Microscopy(SMM). As a result, the sensitivity of the quartz crystal coated with LB films to organic gases is dependent on temperature, thickness of LB film and molecular weight of organic gas.

• 한국조명전기설비학회지:조명전기설비
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• 제7권3호
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• pp.34-40
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• 1993

전기전자산업에 유기분자집합체에 대한 전자 device적 기능을 갖게 하는 초전막형성 기술의 하나로서 LB막이 이용되게 된다. 10여년전에 만들어 대기중에 방치되었던 Langmuir Blodgett(LB) 초전막 시료에 대해서 MIM구조소자에 전하가 발생하는 특성을 검토하였다.그 결과 LB막이 무극성일 때는 상하부전극을 동일 금속으로 하면 전압이 발생하지 않고, 서로 다른 금속전극으로 할 때는 전압이 발생하였는데 양전극금속의 일함수값의 차가 클수록 발생전압이 높았고 LB막이 유극성일때는 동일 전극이라도 전압이 발생하였다.따라서 LB초전막의 MIM 소자에서 발생하는 전하는 단순한 화학작용에 의한 것이 아니고양전극 금속의 일함수와 극성에 관계가 있다고 생각된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.244-246
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• 1991

Recently, a study on LB ultra thin film of molecular size is widely performed. To make use of LB ultra thin film in engineering applications, it is important to investigate how uniformly Langmuir film is deposited on a substrate. In this paper, to confirm the uniformity of film deposition, the relation between the monolayer numbers deposited and its ratio is investigated by deposition of the Y type and Hetero type LB film. If films are deposited ideally, the deposition ratio will become 1.0. From the experimental results, it can be suggested that the deposition of LB film is done well, as we obtained an approximate value 1.0 by the calculation of deposition ratio of L film area and LB film deposition area.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권8호
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• pp.371-375
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• 2001

We attempted to fabricate polyurethane derivatives (PU-CN, PU-DCM) LB films by using LB method. Also, we investigated the monolayer behavior at the air-water interface by surface pressure-area (${\pi}$-A) isotherms. The surface morphologies and the physicochemical properties of LB films were investigated by atomic force microscopy(AFM) and UV-vis spectroscopy, respectively. And, the electrical properties of polyurethane derivatives LB films were investigated by using the conductivity and the dielectric constant. In the surface morphologies, physicochemical and electrical properties of polyurethane derivatives LB films, the properties is different as to the polyurethane derivatives, it is considered that this phenomena could be described by the difference of lumophore pendant which was adhered at PU main chain.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.884-885
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• 1998

The electrical characteristics of Stearic acid Langmuir-Blodgett(LB) films were investigated to develop the gas sensor using LB films. The deposition status of LB films were verified I-V characteristic which was increased with an applied voltage for the number of layers and decreased as increasing the distance of electrode. The conductivity of Stearic acid LB films was $10^{-8}[S/cm]$, which is typical of semiconductor. The conductivity of LB films were increased as the temperature was increased. The activation energy was about 1[eV].

• 약학회지
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• 제40권4호
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• pp.438-441
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• 1996

The therapeutic activity of LB20304a was examined on experimental respiratory tract infection (RTI) caused by Klebsiella pneumoniae DT-S in mice. A single oral dose of LB 20304a (1.2mg/mouse) showed a rapid bacteriocidal activity in lung tissue at 4,7 and 24h after administration of drug. The in vivo activity of LB20304a was comparable to that of ciprofloxacin against K. pneumoniae infection, although in vitro MIC of LB20304a was four-fold higher than that of ciprofloxacin.