• Analytical Science and Technology
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• v.7 no.3
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• pp.261-269
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• 1994

The iodide formed stoichiometrically for sulfide by its oxidation with iodate was extracted as an ion-pair with methylene green into 1,2-dichloroethane and the extract was measured spectrophotometrically at 656nm for the determination of sulfide. Hydrogen sulfide separated from the sample matrix was introduced into a solution containing pH 3.5 acetate buffer and iodate, in which the hydrogen sulfide was completely converted into iodide. A linear calibration graph was obtained over the range $3{\times}10^{-7}{\sim}1.2{\times}10^{-5}M$ sulfide($0.0096{\sim}0.384{\mu}g$ of $S^{2-}/ml$) and the detection limit was $0.0032{\mu}g/ml$. The apparent molar absorptivity and a correlation coefficient(r) were $6.7{\times}10^4L\;mole^{-1}\;cm^{-1}$ and 0.999, respectively. When applied to the stream water samples, the proposed method gave a relative standard deviation of 1.59% at $5{\times}10^{-6}M$ sulfide level.

• Polymer(Korea)
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• v.33 no.5
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• pp.477-484
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• 2009

Suspension polymerization with hydrophobic silica as a stabilizer and AIBN as an initiator was conducted to synthesize PBMA particles and PBMA composite particles containing carbon black. Surface modification of silica particles by controlling pH revealed that 90% of them functioned as stabilizer and 10% were incorporated into PBMA particles. While stabilizer concentration had no impact on reaction kinetics and particle diameter, an increase in stabilizer concentration displayed an increase in molecular weights when it exceeded 1.67 wt%. An increase in initiator concentration and reaction temperature decreased molecular weights in close agreement with the theoretical equation. An increase in carbon black concentration from 1 to 7 wt%, relative to the monomer, showed a progressive decrease in reaction conversion. As carbon black was increased from 3 to 5 wt%, glass transition showed a $4^{\circ}C$ increase. The presence of carbon black was confirmed by TEM while its concentration was measured by TGA.

• KSBB Journal
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• v.4 no.3
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• pp.229-234
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• 1989

NAD+ analogs, 8-( 6-aminohexyl) aminonicotinamide adenine dinucleotide and N6-[(6- aminohewl)-carbamoylmethyl]- NAD+, were imobilized on bovine caseins by the action of hansglutaminase. It appears that NAD+ analogs bind with $\alpha$S1-and $\beta$-caseins through formation of the r-glutamylamine bond between the amino groups attached to the hexyl chains in NAD+ analogs and the glutaminyl residues in caseins. The NAD+ analogs immobilized on the caseins were enzymatically reducible by alcohol dehydrogenase. $\beta$-Casein was more useful carrier than the $\alpha$S1-casein and 8-substituted NAD+ analog was more effective than N6-substituted one in immobilization. Michaelis constant of 8-substituted NAD+ analog immobilized on $\beta$-casein in alcohol dehydrogenase reaction was similar to that of free from of NAD+ and that of NAD+ analog. Immobilized NAD+ was much more stable at alkaline pH than free NAD+ and its analog while maximum velocity was reduced to 31% of the free NAD+ analog. The coenzyme casein conjugated was recovered almost completely in casein precipitated by calcium.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.3
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• pp.45-52
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• 2016

This study is to predict the biogas production and the content analysis of the organic wastes of three islands located in the City of I. Content analysis for a total of six sections, including pH, BOD, COD, three components (Moisture, Ash, Combustibles)was conducted on the specimens of organic wastes from the representative spots of three islands. From the analysis result of organic waste, it is confirmed that more than $1,750,000m^3$ of methane gas per year will be generated through the calculation of the total methane generation for the COD value. Therefore, if the incineration facility for the organic waste in island region is converted into a biogas production facilities which is non-incineration facility, it seems that the organic waste of efficient utilization is available.

• Microbiology and Biotechnology Letters
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• v.17 no.3
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• pp.224-230
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• 1989

For the production of catechol from benzene, bacteria capable of assimilating benzene as a sole carbon and energy source were isolated from soils. Among them, newly isolated strain, KY-114 hay-ing the best ability of producing catechol from benzene was selected and a mutant Pseudomonas sp. HW-103 was developed from Pseudomonas sp. KY-114 by using mutagenesis induced by N-methyl - N'- nitro - N -nitrobo guanidine. The catechol reduction from benzone by Pseudomonas sp. HW-103 was investigated under various conditions. The highest catechol concentration (0.61 g/$\ell$) was obtained in the growth medium (pH 6.5) containing 1% sodium citrate, 0.75% (NH$_4$)$_2$SO$_4$, 0.15% benzene and other minerals at 3$0^{\circ}C$ after incubating of 15hrs. In the catechol production through the reaction with resting rolls, 2.5 g/1 of catechol was produced from 4 g/$\ell$ of benzene after incubation of 10 hrs under the optium conditions, which correponds to 45% of theoretical catechol yield.

• Journal of Plant Biotechnology
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• v.30 no.1
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• pp.65-71
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• 2003

This research aims the production of anti-tumor substances through in vitro culture of hairy roots transformed by Agrobacterium rhizogenes in Artemisia sylvatica MAX and the effect of culture conditions on optimum growth of hairy roots. We investigated the optimum medium, pH, carbon source, sucrose, light, Fe and polyamine conditions of various lines of hairy roots (NK3, NK4, YX. NK3-10) induced from Artemisia sylvatica to increase the optimum growth of hairy roots. MS medium was the best for optimum growth of hairy root clone, NK3-S10. The optimum culture period was 4 weeks for NK3-S10. The optimum sucrose concentration was 3.5%. The optimum concentration of FeSO$_4$, spermine and spermidine was 0.1 mM, 10 mM and 100 mM, respectively.

• Proceedings of the KSEG Conference
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• 2002.04a
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• pp.129-136
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• 2002

대전광역시의 도심하천인 갑천, 유등천, 대전천을 대상으로 하천수의 수리화학적 특성과 동위원소 특성을 분석하였다. 하천의 수리화학적 특성은 상류에서는 $Ca(Mg)-HCO_3$ 유형을 보이다가 도심권을 통과하면서 $Ca(Mg)-SO_4(Cl)$유형으로 전환되고 하류에서는 $Na(Ca)-HCO_3(Cl,{\;}SO_4)$ 유형으로 변화를 보였다. 이와 같은 화학적 유형의 변화는 자연적 영향보다는 인위적 오염물질의 유입에 의한 것으로 해석된다. 하천수의 전기전도도와 수리화학적 유형으로 보면 대전천보다는 유등천과 갑천이 비교적 좋은 수질특성을 보인다. 그러나 하수종말처리장에서 방류되는 방류가 합류되는 갑천하류부터는 수질이 급격하게 나빠진다. 하천수의 pH는 상류에서 중성을 보이다가 도심권을 지나면서 최고 pH 9.8정도의 알카리성을 보인다. 이는 아파트의 우수관을 통한세제 유입에 기인하는 것으로 보인다. 하천수의 ${\delta}^{13}l3C-HCO_3$ 관계에서 중탄산 함량의 증가에 따른 ${\delta}^{13}C$ 값의 증가는 하천수내 $CO_2$의 기원이 유기물에서 무기물의 영향이 커짐을 의미한다. ${\delta}^{34}S-SO_4$의 함량관계는 황산염의 농도가 증가함에 따라서 ${\delta}^{34}S$ 값은 낮아진다. 갑천, 유등천, 대전천의 순으로 황산염의 농도가 증가하고 ${\delta}^{34}S$ 값은 낮아지는 경향을 보인다. 이를 바탕으로 볼 때 갑천 중상류의 경우에는 황산염의 기원이 자연적 반응외 비료 등으로부터 유입된 것으로 보이며, 대전천의 경우에는 유기오염에 의한 황산염의 유입이 상당한 것으로 판단된다. 갑천하류는 하수종말처리장의 방류수의 영향이 큰 것으로 해석된다. 대전시 도심하천수의 수리화학적수질 개선을 위해서는 하수종말처리장의 방류수 기준의 강화, 아파트단지에서의 세제의 유입의 차단, 그리고 부분적인 오염물질의 유입을 차단하여야 할 것이다.

• Applied Chemistry for Engineering
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• v.25 no.6
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• pp.553-558
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• 2014

Microalgae are a promising alternative feedstock for biodiesel production because their growth rates and oil contents are higher than those of conventional energy crops. Microalgal lipid is mainly triacylglyceride that can be converted to biodiesel as fatty acid methyl esters through trans-esterification. In this paper, the influence of several important lipid inducing factors such as nutrient limitation and changes in salinity and metallic components in microalgae and their potential strategies to be used for biodiesel production are reviewed. Depending upon strains/species that we use, microalgae react to stresses by producing different amount of triacylglyceride and/or by altering their fatty acids composition. Although the most widely applied method is the nitrogen starvation, other potential factors, including nutrient surplus conditions and changes in salinity, pH, temperature and metal concentrations, should be considered to increase biodiesel productivity.

• Analytical Science and Technology
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• v.11 no.6
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• pp.452-459
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• 1998

Crosslinked chitin was prepared from epichlorohydrin and chitin which was isolated from waste marin source. The crosslinked chitosan were prepared by the deacetylation of the crosslinked chitin with a strong base. 2,2'-Iminodibenzoic acid-crosslinked chitosan was prepared by reacting 2,2'-Iminodibenzoic acid salt with crosslinked chitosan-Cl which was obtained by chlorination of crosslinked chitosan. The adsorptivity of Pb(II), Cu(II), Cd(II) was studied as a synthetic adsorbent. Experimental results for the adsorption and the recovery characteristics showed that the more pH increase, the more amount of adsorbed metal ion increase. Optimum adsorption time was 1 hr, and adsorption capacity was increased in order of $Cu^{2+}$<$Cd^{2+}$<$Pb^{2+}$, and recovery capacity was increased in order of $Cd^{2+}$<$Cu^{2+}$<$Pb^{2+}$.

• Journal of Life Science
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• v.14 no.2
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• pp.309-314
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• 2004

Cyclic AMP receptor protein (CRP) is involved in the transcriptional regulation of more than 100 genes in E. coli. CRP dimer is converted into active form via the sequential conformation change of cAMP binding pocket, hinge region and HTH DNA binding motif by binding of cAMP. The temperature gradient gel electrophoresis (TGGE) was applied to CRP protein to know whether it was an efficient technique to study the conformational transitions and the thermal stability. TGGE showed the unfolding process of wild-type and S83G CRP proteins with the temperature gradient set from 29 to 71$^{\circ}C$ on nondenaturing polyacrylamide gel. Melting temperature (Tm) was 57$\pm$1 and 55$\pm$1$^{\circ}C$ for wild-type and S83G CRP, respectively in acidic buffer[89.8 mM Glycine and 24 mM Boric acid (pH 5.8)].