• YAKHAK HOEJI
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• v.42 no.2
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• pp.149-152
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• 1998

A high performance liquid chromatographic method was developed for the determination of DA-6034 in biological fluids using internal standard. Plasma containing DA-6034 and inter nal standard was extracted by liquid-liquid extraction at an acidic pH. After evaporation of the organic layer, the drug and internal standard were reconstituted with mobile phase and injected into the column. They were separated by high performance liquid chromatography on inertsil ODS II column at 334 nm. The detection limit of DA-6034 in plasma was 0.02 ${\mu}$g/ml. In this method, the range of recovery and coefficients of variation were 96-110% and 0.40-3.78%, respectively. There was no interference from endogenous substances. Urine and bile were analysed using the deproteinization method and the detection limit of DA-6034 was 1${\mu}$g/l.

• Korean Journal of Microbiology
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• v.24 no.2
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• pp.184-193
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• 1986

Interrelation between environmental influences on soil microorganisms and it's effect on disease development in ginseng (Panax ginseng C.A. Meyer) field were studied to obtain a preventive measures against the root rot of ginseng caused by soil-borne pathogens in soil in three major Korean ginseng producing areas such as Kumsan, Goesan and Poonggi. Populations of actinomycetes were relatively high in fall season from September to November. Their numbers were highly populated in healthy plot in field than replanted disease field of ginseng, whereas ratio of Trichoderma spp to actinomycetes increased in healthy plot of field indicating the higher numbers of Trichoderma spp pressented in healthy plot field. The numbers of propagules of Trichoderma spp generally increased in early summer through early fall season. Their numbers were also highly populated in the healthy plot of fields. The contents of organic matter and phosphate in healthy plot of field were somewhat high, and phophate/organic matter ratio and Mg content were high in diseased replanted field. All of the soil samples showed a weak acidic pH from 4.5 to 4.7. Soilmoisture content was increased during winter season and it did not show any significant changes curing the growing period, showing 24.6% in healthy plot in field and 19.5% in deseased plot in field respectively. Soil temperature was highest in July and August and lowest in January and February.

• Journal of the Korean Electrochemical Society
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• v.5 no.4
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• pp.202-208
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• 2002

We have been investigating electropolymerization of pyrrole in aqueous electrolyte solutions in acidic as well as in neutral conditions by in situ electrochemical quartz crystal oscillator method, where resonant frequency and resonant resistance can be monitored simultaneously with current-voltage measurements during electropolymerization of pyrrole. The properties of thin PPy films prepared on electrode surfaces depended strongly on the experimental variables of electrode potentials applied, solution pH, kinds and quantity of supporting electrolytes, added chemicals, and the mode of electrochemical method employed. We are applying our experience gained on electropolymerization of pyrrole to immobilizing biomolecules onto electrode surfaces to develop a biosensor system. In this work, we wish to present the results on electrochemical monitoring on electropolymerization of pyrrole in the presence of DNA and albumin in different electrochemical conditions. Additionally we will summarize our investigations on the miniaturization of biomolecules/PPy composites by means of scanning tunneling microscopy.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.4
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• pp.570-577
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• 1995

Aspergillus sp. SB-2704 was selected for its strong polygalacturonase activity among various strain of mold found in soil. It was found that production of polygalacturonase reached to maximum when the wheat bran medium containing 1% polypepton, 1% glucose, and 0.2% FeSO4 were cultured for 3 days at 35$^{\circ}C$. Polygalacturonase was purified 20.90 fold from Aspergillus SB-2704. The purification procedures include ammonium sulfate treatment, gel filtration on Sephdex G-150 and DEAE-cellulose ion exchange chromatography. Yield of the enzyme purification was 4.34%. Purified enzyme was confirmed as a single band by the polyacrylamide gel electrophoresis. When the purified enzyme was applied to SDS-polyacrylamide gel electrophoresis, the molecular weight was estimated to be 36,000. The optimum pH for the enzyme activity was 5.5 and optimum temperature was 5$0^{\circ}C$. The enzyme is stable in acidic condition. The activity of purified enzyme was inhibited by Pb2+, Hg2+ and Ba2+, whereas activated by Cu2+, Mn2+, Mg2+ and Fe2+. The activity of polygalacturonase was inhibited by the treament wit maleic anhydride, iodine, and EDTA. The result indicate the possible involvement of histidine and metal ion at active site.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.529-529
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• 2007

Ruthenium (Ru) is a white metal and belongs to platinum group which is very stable chemically and has a high work function. It has been widely studied to apply Ru as an electrode material in memory devices and a Cu diffusion barrier metal for Cu interconnection due to good electrical conductivity and adhesion property to Cu layer. To planarize deposited Ru layer, chemical mechanical planarization(CMP) was suggested. However, abrasive particle can induce particle contamination on the Ru layer surface during CMP process. In this study, zeta potentials of Ru and interaction force of alumina particles with Ru substrate were measured as a function of pH. The etch rate and oxidation behavior were measured as a function of chemical concentration of several organic acids and other acidic and alkaline chemicals. PRE (particle removal efficiency) was also evaluated in cleaning chemical.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.227-230
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• 2004

As the organic acids were added in the slurry, zeta potential of alumina was changed to negative value and IEP value was shifted from alkaline to acidic pH. In citric acid based slurry, Cu surface continuously dissolved and etching depth linearly increased. On the contrary, passivation layer was grown on Cu surface in oxalic acid based slurry. As the platen rotation speed increased, Preston coefficient decreased in both slurries. With oxalic acid based slurry, at low velocity, removal rate is high value because of high friction force compared to citric acid based slurry. As platen velocity increased, removal of Cu in citric acid based slurry became higher value than oxalic acid based slurry. Typical lubrication behaviors were observed in both slurries. As Sommerfeld number increased, COF values gradually decreased and then re-increased. It indicated that lubrication was changed to direct contact or semi-direct contact mode to hydro-lubrication mode.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.5
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• pp.47-53
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• 2010

It is important to utilize the citrus sludge in terms of the reuse of waste materials in the manufacture of corrugated medium. Especially, the mandarin industry occupies the first place in Jeju province. In this paper, the application of citrus sludge mixed with KOCC recycled fibers into the manufacture of corrugated medium was studied. The citrus sludge was acidic in pH value. Also, the constituents of citrus sludge contain some short fibers, fines, and mucus which contain flavonoids, pectins and so on. In papermaking application, these components cause some troubles like foams, bad smell, fouling on the paper machine, and bad drainage and web breaks of wet web. The strength properties of handsheets prepared from KOCC and citrus sludge was decreased, compare to handsheets made of only KOCC. To compensate the problems on strength properties, some kinds of additives were tried to apply into papermaking wet-end system in laboratory scale. As a result, mixing conditions of alum, starch and anionic additives showed the best options in the recovery of strength properties and formations of corrugated medium.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.6
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• pp.64-71
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• 2013

The biodegradable mulching paper could be applied for the environmental friendly agriculture as an alternative to the current vinyl mulching. In order to increase the usability of the mulching paper, the effects of the addition of various inorganic materials on the functionality of the mulching paper were evaluated in terms of practical benefits. The blend of carbonized rice husk powder and perlite resulted in the higher value in the air permeability of the mulching paper, which would be important for the health of plant root. The heat conservative of the mulching paper could be improved by adding the bottom ash or the fly ash because of the pore structure of the ashes. The pH of acidic soil could be neutralized by using the mulching paper containing paper-mill sludge ash or fly ash. The various results showed the addition of the inorganic materials could improve the functional properties of the mulching paper.

• Mass Spectrometry Letters
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• v.4 no.3
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• pp.55-58
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• 2013

Dioscin is a biologically active steroidal saponin with anticancer and hepatoprotective effects. A rapid, selective, and sensitive liquid chromatographic method with electrospray ionization tandem mass spectrometry was developed for the quantification of dioscin in rat plasma. Dioscin was extracted from rat plasma using ethyl acetate at acidic pH. The analytes were separated on a Halo C18 column using gradient elution of acetonitrile and 0.1% formic acid and detected by tandem mass spectrometry in selected reaction monitoring mode. The standard curve was linear ($r^2$ = 0.998) over the concentration range of 1-100 ng/mL. The lower limit of quantification was 1.0 ng/mL using 50 ${\mu}L$ of plasma sample. The coefficient of variation and relative error for intra- and inter-assay at four QC levels were 1.3 to 8.0% and -5.4 to 10.0%, respectively. This method was applied successfully to the pharmacokinetic study of dioscin after oral administration of dioscin at a dose of 29.2 mg/kg in male Sprague-Dawley rats.

• Journal of the Korean Magnetic Resonance Society
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• v.9 no.2
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• pp.74-92
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• 2005

The high resolution solution structure of MCP-3 was determined using multinuclear, multidimensional NMR spectroscopy with an expressed and $^{13}C-\;and\;^{15}N-labeled$ protein. The MCP-3 has a typical chemokine fold including 3 anti-parallel $\beta-sheets$, and a C-terminal helix, but it exists as a monomer in solution under the conditions where the structure was determined (2 mM, pH 5.1 at $30^{\circ}C$). Based on the structure and the amino acid sequence compared to other chemokines we propose that Ile20 and Leu25 in MCP-3 play key roles in the formation of N-loop (residues between the $2^{nd}$ cysteine and the I sheet) which has been implicated as a determinant of chemokine specificity. Additional receptor binding surface is supplied by the 40s loop (residues between the 2 and the 3 sheet) and the binding interface of the acidic N-terminal region of chemokine receptor to MCP-3 would resemble the dimerization interface of CC type dimer.