• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.3
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• pp.207-215
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• 2011

An endosulfan degrading bacterial strain, K-1321, was isolated by endosulfan-enrichment culture from a seaside sediment collected at Dadaepo Beach, Busan, Korea. The strain was identified as a Serratia sp. based on the results of morphological, biochemical and 16S rDNA homology analyses. Serratia sp. K-1321 was able to completely degrade 50 ppm endosulfan in culture media and soil within 6 weeks at $25^{\circ}C$. GC/MS analysis revealed that endosulfan diol was an intermediate of the bacterial endosulfan degradation. Considering the above results, we concluded that Serratia sp. K-1321 utilized endosulfan as a carbon source and metabolized endosulfan via a less toxic pathway, such as the formation of endosulfan diol as an intermediate.

• Journal of the Korean Applied Science and Technology
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• v.37 no.1
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• pp.49-55
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• 2020

In this study, isophorone diisocyanate (IPDI) and dimethylolbutanoic acid (DMBA) were used on the basis of poly caprolactone diol (3M, 3.5M, 4M, 4.5M) for the synthesis of water-based polyurethanes for coating on skin layers of leather. Tensile strength, elongation, and adhesive strength of the prepared samples were measured. As a result of measuring the tensile strength, the tensile strength was found to be 4.09 kgf / ㎟ when 3 moles were applied, and 1.071 kgf / ㎟ when 4.5 moles were applied. Elongation was 366 % when 3 moles of PCL were applied, and 709 % at 4.5 moles. Adhesive strength was 2.887 kgf / cm when 3 moles of PCL was applied and 0.998 kgf / cm when 4.5 moles were applied.

• Microbiology and Biotechnology Letters
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• v.27 no.2
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• pp.107-112
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• 1999

A bacterium, which can utilize cyclohexanol as a sole source of carbon and energy, was isolated from sludge in sewage of Ulsan Industrial Complex for Petrochemicals, Korea and identified as Rhodococcus sp. TK6. The growth conditions of the bacteria were investigated in cyclohexanol containing media. The bacteria utilized cyclohexanol, cyclohexanone, cyclohexane-1,2=diol, cyclopentanol, cyclopentanone, and $\varepsilon$-caprolactone but not cyclohexane, cyclohexane-1,2-dione, and cyclooctanone. The bacteria were able to utilize alcohols such as ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 2-methyl-1-propanol, 3-methyl-1-butanol, 2-propanol, and 2-butanol as well as cyclohexanol, organic acids such as adipate, propionate, butyrate, valerate, n-caproate, and 6-hydroxycaproate, and aromatic compounds such as phenol, salicylate, p-hydroxbenzoate, and benzoate as a sole source of carbon and energy. Cyclohexanone as a degradation product of cyclohexanol by Rhodococcus sp. TK6 was determined with gas chromatography.

• Natural Product Sciences
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• v.20 no.2
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• pp.91-94
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• 2014

Column chromatographic separation of the MeOH extract from the tubers of Bletilla striata yielded seven phenolic components including four phenanthrenes, 3,7-dihydroxy-2,4-dimethoxyphenanthrene (1), 3,7-dihydroxy-2,4,8-trimethoxyphenanthrene (2), 9,10-dihydro-4,7-dimethoxyphenanthrene-2,8-diol (3), and 9,10-dihydro-1-(4'-hydroxybenzyl)-4,7-dimethoxyphenanthrene-2,8-diol (4) and three stilbenes, gigantol (5), 3',4"-dihydroxy-5',3",5"-trimethoxybibenzyl (6), and batatasin III (7). Their structures were determined on the basis of NMR spectroscopic data. Among them, compound 2, 3, and 6 were reported for the first time from this plant. The isolated compounds (1-7) were tested for cytotoxicity against four human tumor cell lines in vitro using a Sulforhodamin B bioassay.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.418-418
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• 2012

We fabricated a new type of hybrid film using molecular layer deposition (MLD). The MLD is a gas phase process analogous to atomic layer deposition (ALD) and also relies on a saturated surface reaction sequentially which results in the formation of a monolayer in each sequence. In the MLD process, polydiacetylene (PDA) layers were grown by repeated sequential surface reactions of titanium tetrachloride and 2,4-hexadiyne-1,6-diol with ultraviolet (UV) polymerization under a substrate temperature of $100^{\circ}C$. Ellipsometry analysis showed a self-limiting surface reaction process and linear growth of the hybrid films. Polymerization of the hybrid films was confirmed by infrared (IR) spectroscopy and UV-Vis spectroscopy. Composition of the films was confirmed by IR spectroscopy and X-ray photoelectron (XP) spectroscopy. The titanium oxide cross-linked polydiacetylene (TiOPDA) hybrid films exhibited good thermal and mechanical stabilities.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.91-98
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• 2015

Formamide의 중성가수분해 mechanism은 QM/MM (quantum mecahnics/molecular mechanics) molecular dynamics simulations 및 CPMD과 같은 방법으로 연구되어왔다. 본 연구에서는. Umbrella sampling을 이용한 QM/MM-MD simulation을 사용하여 4가지 반응의 free energy surface를 도출해냈다. 전체적으로, 가장 선호되는 메커니즘은 two step으로 구성된 water assisted stepwise mechanism이었으며 모든 mechanism은 ab-initio calculation과 QM/MM-MD simulation이 수행되었다. water assisted stepwise mechanism을 살펴보면, 첫 번째 step에서 formamide의 carbonyl group이 hydrate되면서 gem-diol intermediate를 형성한다. 다음 step에서, intermediate의 hydroxyl group으로부터 amino group으로 water-assisted proton transfer이 일어난다. 두 반응 모두에서 물이 proton transfer를 직접적으로 도와주는 것을 관찰할 수 있었다. 특히, ab-initio calculation과는 다르게 QM/MM-MD에서는 gem-diol intermediate가 안정화되는 것으로 solvent effect를 잘 보여준다.

• Archives of Pharmacal Research
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• v.20 no.2
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• pp.191-193
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• 1997

A new nortriterpene, rhombenone (1) was isolated from the leaves of Hedera rhombea Bean (Araliaceae). The structure of this compound was established as 27-demethyl-20(S)-dammar-23-ene-$6{\alpha}$, 20-diol-3, 25-dione on the basis of spectral analysis including HMQC and HMBC techniques. Rhombenone (1) was the first 27-demethyl nortriterpene of dammarane type isolated from natural sources.

• Bulletin of the Korean Chemical Society
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• v.26 no.6
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• pp.913-915
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• 2005

The three new lignans 1-3 were isolated from the methanol extracts of the flower buds of Magnolia fargesii. They were elucidated as (7S,8R)-1-(3,4-dimethoxyphenyl)-2-O-(2-methoxy-4-omegahydroxypropylphenyl) propane-1,3-diol, (7S,8S)-1-(4-hydroxy-3-methoxyphenyl)-2-O-(6-hydroxy-2-methoxy-4-omegahydroxypropylphenyl) propane-1,3-diol, and [tetrahydro-4-hydroxy-2-(3,4,5-trimethoxyphenyl)furan-3-yl]methyl 3,4-dimethoxy benzoate by spectral analysis.

• Elastomers and Composites
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• v.55 no.1
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• pp.20-25
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• 2020

The effect of the isocyanate index (NCO index) on the particle size and particle size distribution of a waterborne polyurethane dispersion (WPUD) with polycarbonate-diol was determined. The WPUDs were prepared using a conventional acetone process with polycarbonate-polyol (M_n = 2028), 4,4'-methylenebis(cyclohexyl isocyanate) (H₁₂MDI), 2,2-bis(hydroxymethyl) propionic acid (DMPA), and dibutyltin dilaurate catalyst. At NCO index values below 1.5, the number average particle diameter of the WPUDs significantly increased with the NCO index, whereas the particle diameter slightly varied at higher NCO indexes. The dependency of the WPUD viscosity on the NCO index exhibited similar behavior to that of the particle size. The relative values of the full width at half maximum of the WPUD particle distribution curves at various NCO indexes were not influenced by the NCO index.

• YAKHAK HOEJI
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• v.39 no.1
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• pp.85-93
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• 1995

Acidic and alkaline hydrolysis of diol-type ginseng saponins produced a new glycoside, (20E)-ginsenoside Rh$_{3}$, and its stereoisomer (20Z)-, which were further subjected to alkaline by drolysis to give their aglycones, (20E)- and (20Z)-3$\beta$, 12$\beta$-dihydroxy-dammar-20(22),24-diene. The ratio of stereoisomeric mixtures was estimated to be ca. 5:1 from intensities of the peaks in $^{1}$H- and $^{13}$C-NMR spectra. The $^{1}$H- and $^{13}$C-NMR signals of ginsenoside Rh$_{3}$, which have remained unclarified, were completely assigned by the extensive application of modern NMR techniques.