• Journal of Korean Society of Environmental Engineers
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• v.31 no.4
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• pp.278-286
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• 2009

In this study, four natural Mn oxides ($NMO_1-NMO_4$) was characterized using x-ray diffraction, scanning electron microscopy, and their removal efficiency for 1-naphthol (1-NP) in aqueous phase, using batch reactor, was investigated. The results were compared with one another and a synthetic manganese oxide, birnessite. The NMOs have a various Mn minerals including pyrolusite (${\beta}-MnO_2$), cryptomeltane (${\alpha}-MnO_2$) as well as birnessite (${\delta}-MnO_2$) depending on their sources, which results in different removal efficiencies (removals, kinetics) and reaction types (sorption or oxidative-transformation). The comparative study showed that $NMO_1$ (electrolytic Mn oxide) have a higher removal efficiency for 1-NP via oxidative-transformation compared to birnessite. The 1-NP removals by NMOs were followed by pseudo-first order reaction, and the surface area-normalized specific rate constants ($K_{surf},\;L/m^2$ min) determined were in order of $NMO_1(3.31{\times}10^{-3})$>${\delta}-MnO_2(1.48{\times}10^{-3}){\fallingdotseq}NMO_3(1.46{\times}10^{-3})$>$NMO_2(0.83{\times}10^{-3})$>$NMO_4(0.67{\times}10^{-3})$. From the solvent extraction experiments with the Mn oxide precipitates after reaction, it was observed that the oxidative-transformation rates of 1-NP were in order of $NMO_1{\fallingdotseq}{\delta}-MnO_2$>$NMO_3$>$NMO_4{\gg}NMO_2$ and the analysis of HPLC chromatogram and UV-Vis. absorption ratios ($A_{2/4}$, $A_{2/6}$) on the supernatant confirmed that the reaction products were oligomers formed by oxidative-coupling reaction. Results from this study proved that natural Mn oxide (except $NMO_2$) used in this experiment can be effectively applied for the removal of naphthols in aqueous phase, and the removal efficiencies are depending on the surface characters of the Mn oxides.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.3
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• pp.217-222
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• 2011

Success in molecular breeding for better adapted varieties to environmental stresses depend upon the concerted efforts by various research including tissue culture, transformation, genetics and breeding. In order to optimize tissue culture conditions of Siberian wildrye grass, the effects of plant growth regulators on callus induction and plant regeneration were investigated with mature seeds. The highest callus induction frequency was observed when the mature seeds were cultured on MS medium supplemented with 5 mg/L 2,4-D. The highest plant regeneration frequency was observed when callus was transferred to N6 medium supplemented with 1 mg/L 2,4-D and 3 mg/L BA. Regenerated plants were grown normally when shoots were transplanted to the soil. A short tissue culture period and regeneration system would be beneficial for molecular breeding of Siberian wildrye grass by the production of transgenic plant.

• KSBB Journal
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• v.5 no.3
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• pp.247-253
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• 1990

These studies were carried out to obtain the transformant from carrot cells by using binary vector pGA472 with NPT II gene to confer kanamycin resistance in the plant cells. The binary vector pGA472 was mobilized from E. coli MC1000 into A. tumefaciens strains isolated in the Korea, C23-1. K29-1, and disarmed Ti-plasmid PC2760, and A28l using a tri-parental mating method with E. coli HB101/pRK2013. Transconjugants, C23-1/pGA472, K29-1/pGA472, PC2 760/pGA472 and A28l/pGA472 were obtaind on the minimum AB media containing tetracycline and kanamycin, were comfirmed to hold the Ti-plasmid and pGA472 binary vector on the 0.7% agarose gel. Transformed carrot calli were initiated on the MS media supplemented with l00$\mu\textrm{g}$/ml kanamycin and 250$\mu\textrm{g}$/ml carbenicillin after co-cultivation of carrot explant and transconjugant Agrobacteria. Selected callus was grown vigouousley for subculture on the medium containing 100$\mu\textrm{g}$/ml kanamycin, thus indication that the selected callus was transformed with NPT II gene.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.199-199
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• 2011

The addition of a carbanion to ${\yen}{\acute{a}}{\yen}{\hat{a}}$-unsaturated carbonyl compounds is of importance in the C-C bond formation reactions for modern pharmaceuticals and organic synthesis. Recently, heterogeneous asymmetric catalysis became more attractive area of research because of the easy recovery and separation of the catalyst from the reaction system. Most of synthetic methods for heterogeneous catalysts were grafting or immobilization of homogeneous catalyst onto the solid supports. Trans-1,2-Diaminocyclohexane(DACH) and L-proline ligands have been enormously used as chiral ligands in several catalytic transformation under homogenous conditions. Our group prepared l-proline functionalized mesoporous silica was synthesized under acidic condition using a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer template (EO20PO70EO20, Pluronic P-123, BASF). Furthermore, we successfully directly synthesized trans-1,2 diaminocyclohexane functionalized mesoporous silica by using microwave method. The direct functionalization of chiral ligand into the framework of mesoporous materials is expected to be useful for the heterogeneous asymmetric catalysis. So, we adopt the direct synthesis of chiral ligand functionalized mesoporous silica by using thermal and microwave irradiation. Then, chiral ligand functionalized mesoporous silicas were applied to enantioselective asymmetric catalytic reactions.

• Journal of Korean Society on Water Environment
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• v.20 no.3
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• pp.290-295
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• 2004

In this study, ozone was adopted for the reduction and stabilization of waste sludge from the municipal sewage treatment plant. The waste sludge used in the experiments was primary sludge, excess sludge and a mixture of the two. The sludge cells and flocs were disrupted by ozonation resulting in the reduction of TSS and VSS concentrations. In the case of the primary sludge with a concentration of 20 gTS/L, the TSS and VSS concentrations were reduced 28%, 33% and the TCOD concentration was reduced 20% respectively. The consumption of ozone was $0.18gO_3/gSS$. In the case of the excess sludge with a concentration of 7.5 gTS/L, the TSS and VSS concentrations were reduced 37%, 41%, and the TCOD concentration was reduced 19% respectively. The consumption of ozone was $0.33gO_3/gSS$. In the case of the mixed sludge of 9.3 gTS/L, the TSS and VSS concentrations were reduced by 45%, 53%, and the TCOD was reduced 26% respectively. The desirable consumption of ozone was $0.27gO_3/gSS$. As ozonation proceeded, the level of SCOD increased due to the release of intracellular materials. However TCOD was reduced due to mineralization resulting from the transformation of organic materials to inorganic materials.

• Economic and Environmental Geology
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• v.39 no.6 s.181
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• pp.689-697
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• 2006

Distribution and speciation of arsenic in water resources was investigated in the Ulsan mine area. In 62% of uoundwater samples from the mine area, total As concentrations exceeded 0.05 mg/l, the Korean Drinking Water Standard. As(V) was the major type in groundwater with minor As(III). Arsenic species appeared to be in transition stages following redox changes after exposure to the air through the monitoring wells. In areas around the mine, the mine and Cheongog spring appeared to be the sources of arsenic contamination of water resources. The spring showed 0.345 mg/1-As, as much as seven times of the Korean standard. Groundwater and stream samples showed As-concentrations greater than 0.05 mg/l in 30% and 33% samples, respectively, and 60 and 67% of samples exceeded 0.01 mg/l of WHO guideline, respectively. Again, As(V) was a dominant species, however, several samples had As(III) in appreciable levels. In one stream sample, organic species including DMA and AsB were detected in low levels, probably resulted from transformation or related biogeochemical processes.

• KSBB Journal
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• v.22 no.1
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• pp.16-21
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• 2007

Although Energy demands of modern society increase rapidly, current energy would be exhausted shortly. Therefore development of bio-ethanol production process from cellulose containing materials was extremly demanded. Therefore development of highly functional cellulase is requisite for this purpose. In this study cellobio-hydrolase (CBH1) gene from Trichorderma reesei was used to increase cellulase activity by directed evolution and highly functional cellobio-hydrolase was obtained and characterized.

• Journal of Plant Biotechnology
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• v.34 no.3
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• pp.223-227
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• 2007

Plant regeneration system from leaf and root segments of Lycoris chejuensis via bulblet formation was established. Surface-sterilized leaf and root segments were cultured on the B5 medium containing 2,4-D. After 12 weeks of culture onto B5 medium containing 2,4-D, white globular structures and white calluses were formed on the cut surface of the explants. The highest frequency of globular structures and calluses formation from leaf explants was 32.1% when leaf explants were cultured onto B5 medium supplemented with 1 mg/L of 2,4-D. However, the higher concentration of 2,4-D (over than 3 mg/L) resulted in decrease of the frequency. In comparison to leaf explants, root segments showed the highest frequency at a rate of 36.1% when root explants were cultured onto B5 medium supplemented with 3 mg/L of 2,4-D. These structures and calluses were sub-cultured and proliferated onto the same culture medium. Upon transfer to B5 basal medium, white globular structures were developed into bulblets and normal plantlets. After 4 weeks of incubation in the light, plantlets were successfully rooted over the frequency of approximately 90%. Rooted plantlets were successfully transferred to potting soil and acclimatized in the growth chamber. The plant regeneration system of Lycoris chejuensis established in this study, might be applied to mass proliferation, conservation of genetic resources and genetic transformation for molecular breeding.

• Journal of Plant Biotechnology
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• v.31 no.1
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• pp.43-48
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• 2004

As an initial step for future genetic manipulations to improve forage characteristics of Italian ryegrass (Lolium multiflorum Lam.), an efficient tissue culture system was established and the factors affecting plant regeneration were evaluated. MS medium containing 5mg/L 2,4-D was optimal for embryogenic callus induction from mature seed and had a strong effect on successive plant regeneration. The plant regeneration frequency was observed at above 70％ when embryogenic calli induced were transferred to N6 medium supplemented with 1mg/L 2,4-D and 5mg/L BA. Among several basic media tested, MS and N6 medium were optimal for callus induction and plant regeneration, respectively. Genotype was an important factor in plant regenerability. 'Jeanne' showed the highest regeneration frequency of 73％. A short tissue culture period and high-frequency regeneration system established in this study will be useful for molecular breeding of Italian ryegrass through genetic transformation.

• Journal of Plant Biotechnology
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• v.33 no.4
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• pp.271-276
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• 2006

Hypocotyl explants of Chinese cabbage (us. 'Jeong Sang' and 'Seoul') produced adventitious shoots on Murashige and Skoog (MS) basal medium supplemented with 4mg/L $AgNO_3$, 5 mg/L acetosyringone, 4 mg/L 6-benzyladenine and 3mg/L alpha-naphthaleneacetic acid (SI) after cocoultivation with strains of Agrobacterium tumefaciens (LBA4404) harboring the pCAMBIA1301 and the $_PPTN290$ containing hygromycin-resistance gene and paromomycin-resistance gene as a selectable marker genes, respectively. There was a significant difference in the frequency of transgenic plants depending on antibiotics and cultivars used. Paromomycin was better than hygromycin, and cultivar 'Jeong-sang' was higher than 'c.v. Seoul' in the frequency of transgenic plants. In particular, the highest frequency (0.70%) of transgenic plants was obtained from selection medium (SI) containing 100mg/L paromomycin in c.v., 'Jeong-sang' GUS positive response were obtained 9 plants and 3 plants from the cultivars, 'Jeong-sang' and 'Seoul', respectively. They were grown to maturity in a greenhouse and normally produced $T_1$ seeds. GUS histochemical assay for progeny $(T_1)$ revealed that the transgenes were expressed in the plant genome.