• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.255-263
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• 2016

Antimicrobial properties of Licorice(Glycyrrhizae radix L.) against food spoilage microorganism, Bacillus subtilis KCTC 1021 was investigated. Antibacterial activity of the essential oil was as equivalent as Potassium metabisulfite and myconazole. The licorice extracts was fractionated to hexane, chloroform, ethyl acetate, butanol and water fraction. Chloroform fraction showed the highest inhibitory effect on the Bacillus subtilis KCTC 1021. Chloroform fraction was further fractionated by silica gel column chromatography and thin layer chromatography(TLC). The antibacterial compound was isolated from their fractions and its chemical structures was identified as (R)-glabridin by ESI-MS, $^1H$-NMR and $^{13}C$-NMR.

• Transactions of the Korean hydrogen and new energy society
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• v.2 no.1
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• pp.47-56
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• 1990

Pure titanium rods were oxidized by anodic oxidation, furnace oxidation and flame oxidation and used as a electrode in the photodecomposition of water. The maximum photoelectrochemical conversion efficiency(${\eta}$) was found for flame oxidized electrode ($1200^{\circ}C$ for 2 min in air), 0.8 %. Anodically oxidized electrodes have minimum photoelectrochemical conversion efficiencies, 0.3 %. Furnace oxidized electrode ($800^{\circ}C$ for 10min in air) has 0.5% phtoelectrochemical efficiency and shows a band-gap energy of about 2.9eV. The efficiency shows a parallelism with the presence of the metallic interstitial compound $TiO_{O+X}$(X < 0.33) at the metal-semiconductor interface, the thickness of the sub oxide layer and that of the external rutile scale.

• Journal of the Korean Ceramic Society
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• v.35 no.3
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• pp.219-230
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• 1998

Various interlayer materials have been tested for active metal(Cusil ABA) brazing of Si3N4/S. S316 joint. In general multilayer joint had higher strength(80-150 MPa) and better reliability than monolayered one. The joint with Cu(0.2)/Mo(0.3)/Cu(0.2mm) interlayer showed the highest bending strength of abou 490 MPa and the joint with Cu(0.2)/Mo(0.3mm) interlayer the best reliability (14.6 Weibull modulus). The stresses distributed in joint materials during 4-point bending test were estimated by CAE von Mises analysis; the estimated stresses were In good agreement with the measured data. In multilayer joint Cu was though to reduce the residual stresses induced by the difference in thermal expansion coefficient between the ceramic Mo and metal It apperared that a Cu/Mo was optimum interlayer material for Si3N4/S. S316 joint with high bending strength (420 MPa) and reliability. In addition the various shapes and types of compound were examined by EPMA in joining interface.

• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.63-70
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• 2001

To identify and evaluate the benzidine-DNA adducts in liver and bladder, we exposed the 80 ppm benzidine to 40 sprague-dawley rats by drinking water for 4 weeks(6.2 mg/kg body wt./day). Only one benzidine-DNA adduct was found at the same site of thin layer chromatogram of $^{32}$ P-postlabeling method in the liver and bladder of exposed rats. So we know the DNA adduct formed at liver and bladder were similar to each other, which was N-(deoxyguanosin-8-yl)-N'-acetylbenzidine. Relative adduct labeling(RAL) of DNA adduct was similar to each other for 1 and 2 weeks, but that in liver was significantly higher than in bladder for 3 and 4 weeks. RAL$\times$10$^{9}$ of DNA adduct were 84.45$\pm$11.31 and 152.8$\pm$5.53 in liver, and were 24.76$\pm$7.06 and 38.00$\pm$10.57 in bladder for 3 and 4 weeks, respectively. Regression equation between liver and bladder was Y=-3.801+2.507 X(r=0.6036, p<0.01). In conclusion, benzidine-DNA adduct formed in liver was significantly higher than that in bladder, with the similar compound structure in sparague-dewley rates treated benzidine in drinking water.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.1
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• pp.14-20
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• 2016

This paper describes a green stripping process to effectively strip the remaining DFR layer on a non-alkali-based ITO glass surface after an etching process. A stripper, water-soluble amine compound, is used to investigate the characteristics of stripping ability and to suggest a valid method for the green process. Increasing the composition (5-30% concentration) of the ethanol amine-based stripper was found to greatly reduce the stripping time applied in the dipping method. The composition (30%) achieved an excellent stripping effect and free-residue impurities. Additionally, it was possible to obtain the effect of stripping in a way to sustain the release before generating DFR sludge from the ITO glass surface by using dipping condition (stripping time) in the composition. An Additional stripping process (buffering) out of dipping can realize productivity improvement and cost reduction because of the higher proportion of re-use of the stripping solution used in the DFR removal step.

• Journal of Pharmaceutical Investigation
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• v.26 no.2
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• pp.99-103
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• 1996

Effects of glycerin and PEG 400 in donor and receptor solutions upon skin permeation of drug were investigated. Deoxycortisone was used as a model compound. In vitro skin permeation study with freshly excised hairless mouse skin was performed and the steady-state skin permeation rates of the drug were determined in different fractions of glycerin or PEG 400 in donor and receptor solutions. Glycerin in donor solution didn't show any effect on the skin permeation rate of deoxycortisone. However glycerin in receptor solution showed significant effect on the skin permeation rate of the drug. In glycerin, there's a critical concentration for balancing hydration and dehydration of skin. At low concentration, less than 20 %, glycerin showed the enhancement of the flux due to the hydration effect of skin. At high concentration, more than 30 %, glycerin retard the permeation rate which might be due to the dehydration effect on the dermis layer. Since dermis has more water content than the stratum corneum, the steady state skin permeation rates were more influenced when glycerin was in receptor solution than that of in donor solution. PEG 400 aqueous solutions doesn't affect the steady state permeation rate of deoxycortisone significantly.

• Applied Biological Chemistry
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• v.36 no.2
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• pp.134-137
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• 1993

Yongia sonchifolia Max. has been used as raw materials of traditional Kimchi and medicinal herb in Korea. This study was performed to investigate biologically active components in the plant. First, the writer carried out the experiment of antitumor screening test against Sarcoma-180A and the cytotoxic activity against Chinese hamster V-79 cells with methanol extract of the plant. And the aqueous solution of the extract from roots of Youngia sonchifolia Max. was partitioned into n-hexane. The concentrated extract of n-hexane layer was chromatographed on silica gel column and developed with n-hexane and ethylacetate. Two yellow elutes, on concentration, were recrystallized from ethylacetate, and the $R_f$ value of TLC of the crystal was 0.43. After analysis by $^{1}H-NMR$, $^{13}C-NMR$ and MS to confirm the structure, the author could identify the compound as bauerenyl acetate, a naturally occurring pentacyclic triterpene. The crystal was colorless plate and m.p. was $280{\sim}282^{\circ}C$.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.562-567
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• 2017

The organic light-emitting diodes are fabricated with six anthracene derivatives containing simple substituents such as phenyl or naphthyl group. The device structure is as in the following: Indium tin oxide (ITO) (180 nm)/4,4-4,4',4"-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (2-TNATA) (30 nm)/4,4'-bis[N-(1-naphthyl)-N-phenyl-1-amino] biphenyl (NPB) (20 nm)/Emitting compound (30 nm)/2,2',2"-(1,3,5-Benzinetriyl)-tris (1-phenyl-1-H-benz-imidazole) TPBi (40 nm)/lithium quinolate (Liq) (2 nm)/Al (100 nm). In the emitting layer the anthracene derivatives are used without any dopant. All the six devices show blue emissions. Among the tested diodes, the one with 9-(2-naphthyl)-10-(p-tolyl) anthracene (2-NTA) exhibited luminous efficiency, power and external quantum efficiencies of 3.26 cd/A, 0.98 lm/A, 2.8 % at $20mA/cm^2$.

• Journal of Microbiology and Biotechnology
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• v.20 no.9
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• pp.1259-1265
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• 2010

The filamentous cyanobacterium Arthrospira platensis strain MMG-9 was isolated from a rice field. The ability of this strain to synthesize the bioactive compound indole-3-acetic acid (IAA) was demonstrated. IAA was extracted from the culture of A. platensis strain MMG-9 and its identity was confirmed by thin-layer chromatography (TLC) as well as by high-performance liquid chromatography (HPLC). The IAA precursor L-tryptophan was required for IAA biosynthesis. Released IAA increased with the increase of the initial concentration of L-tryptophan in the medium and with the incubation time. A. platensis strain MMG-9 accumulated more IAA than it released into the medium. The bioactivity of the secreted IAA was shown by its effect on the formation of roots by Pisum sativum. There was a significant positive effect of the supernatant of cultures of A. platensis strain MMG-9 on the number of lateral roots of P. sativum, whereas a negative effect on root length was observed.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.23 no.2
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• pp.63-70
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• 1997

It has been observed that local increase in melanin synthesis or uneven distribution can cause local hyperpigmintation or spot. Pigmentary disorders are caused by various factors, including inflammation, imbalance of hormones, and genetic disorder. Recently the harmfulness of Ultraviolet radiation is increasing due to destruction of ozone layer. Excessive exposure to UV radiation caused post-inflammatory pigmentation. Most women want to avoid uneven skin pigmentation. To satisfy this desire many cosmetic companies have been developing melanogenesis inhibitors and finding promising active agents for use in cosmetic preparations for skin whitening. In cosmetic preparations, many inhibitors such as kojic acid, arbutin, ascorbic acid, and licorice extracts6 have been used as whitening purpose. Plant extracts having an inhibitory effect on melanin formation may be a good choice for cosmetic purpose because of their relatively lower side effects. Therefore, we screened 285 plant extracts for their inhibitory activity in tyrosinase. Of the plant extracts, ramulus mori extracts showed potent tyrosinase inhibition activity. We also identified the active compound in the extract.