• Mass Spectrometry Letters
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• v.3 no.4
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• pp.93-100
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• 2012

Cellular processes such as proliferation, differentiation, and adaptation to environmental changes are regulated by protein phosphorylation. In order to enhance the understanding of molecular dynamics for biological process in detail, it is necessary to develop sensitive and comprehensive analytical methods for the determination of protein phosphorylation. Neural stem cells hold great promise for neural repair following an injury or disease. In this study, we made differentiated oligodendrocytes from human neural stem cells using over-expression of olig2 gene. We confirmed using quantitative phosphoproteome analysis approach that combines stable isotope labeling by amino acids in cell culture (SILAC) and $TiO_2$ micro-column for phosphopeptide enrichment with $MS^2$ and $MS^3$ mass spectrometry. We detected 275 phosphopeptides which were modulated at least 2-fold between human neural stem cells and oligodendrocytes. Among them, 23 phosphoproteins were up-regulated in oligodendrocytes and 79 phosphoproteins were up-regulated in F3 cells.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.4
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• pp.288-294
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• 1994

Seedling vigor of introgressive hybrids between birdsfoot refoil 'MO-20"(Lotus corniculatus) used as the maternal parent and tetraploid(2n=4x=24)accession PI302921 narrowleaf trefoil(Lotus corniculatus L.), and parents were compared in terms of dry matter accumulation , net photosynthetic rate, dark respiration rate, and growth analysis. The hybrids showed better seedling vigor than PI302921 as they had lower dark respiration rate and higher relative growth rate (RGR) than PI302921. Hybrids grew faster than MO-20, but there was not significant difference between them. Net photosynthesis per unit area increased during three weeks after emergence without difference among the entries, then decreased sharply with leaf age and shading marking much differences among entries Dark respiration rate was very high just after emergence, after which it decreased rapidly until it reached a stable level at 1 week through 3 weeks of age, and then dropped again. In general, dark respiration, photosynthesis, and seedling growth of the hybrid was similar to those if MO-20. Although there are some reports about interspecific hybrids of Lotus species, it still remains as a new area for genetic improvement of seedling vigor of L. corniculatus.atus.

• Journal of Life Science
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• v.11 no.5
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• pp.457-463
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• 2001

A bacterial strain SC-22 which produced alkaline lipase was isolated from salf-fermented shrimps. Strains SC-22 was identified as Staphylococcus xylosus. An alkaline lipase excreted by Staphylococcus xylosus SC-22 was purified by ammonium sulfate predipitation and column chromatography on Sephadex G-100 and DEAE-Sephace. The specific activity of purified lipase was 756U/mg of protein with 17.2% yield. The approximate molecular weight of the purified enzyme was 47 kDa. The partially purified lipase preparation had and optimum temperature of 4$0^{\circ}C$, an optimum pH of 8.0, and a stable of 5~10. Lipase activities were enhanced by salt ions such as $Ca^{2+}$, $Mg^{2+}$,N $a^{2+}$ while inhibited remarkably by heavy metal ions, C $u^{2+}$ and P $b^{2+}$.EX> 2+/.

• Progress in Medical Physics
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• v.12 no.2
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• pp.141-146
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• 2001

It is well known that assurance of the radiation therapy needs for an accuracy of $\pm$ 5 % in the delivery of an absorbed dose to target volume. Therefore, the dose evaluation of brachytherapy source and/or linear accelerate beam must be a stability with accuracy. In an advanced country, they recommended to use the radioactive check source for reference air ionization chamber for a stable response of radiation field chamber. In this experiments, the radioactive source Sr-90 and PR-05 air ionization chamber were used for standard source and reference ion chamber. The response of reference ion chamber showed as an 1.000$\pm$ 0.010 uncertainty for 10 years long and the evaliuation f dose discrepancy of clinical field ion chamber showed as 0.997 $\pm$0.011 in a $^{60}$ Co brachytherapy soruce. In our experiments, we can assuarance the long halflife standard source is reliable to preserve the calibration factor of reference chamber in stability.

• The Korean Journal of Zoology
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• v.33 no.1
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• pp.6-11
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• 1990

Analysis of genetic structure in Kimpo natural population of Drosophila was carried out by utilizing the deleterious gene on the second chromosome of Drosophila melanogaster. Male flies tested were continuously collected for eight years; in late September 1974 and 1981-1987. The frequency of deleterious gene (lethal plus semilethal) ranged from 27.02% in 1983 to 41.48% in 1987, and the values estimated from the eight years samples are highly signihcent from each other with a homogenety test (X$^2$=52.0157, d.f.=28, P<0.005). Allelic rates ranged from 1.30% in 1981 to 5.03% in 1974. And the effective population size by using the rate of allelism was estimated average at 3, 300 pairs. Elimination rate by homozygous of lethal gene ranged from 0.0004 in 1984 to 0.0019 in 1974, and that is for smaller than mutation rate(0.005) at second chromosome. We suppose that stable frequency (about 20%) lethal genes of D. melanogaster in Kimpo natual population are maintained by invade of P-type mutator factor (P element) versus eliminated in heterozygous and homozygous condition of lethal gene.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.5
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• pp.681-689
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• 2011

Submerged membrane bio-reactor (SMBR) has several advantages such as high MLSS, long SRT, and low F/M ratio at wastewater treatment. So, this has widely applied over the world and many studies have been conducted. However, membrane fouling remains an inevitable problem. This study was investigated using bench-scale SMBR with three poeration modes. Raw waters were prepared by addition of starch, acetic and fibric acid to recovery water of zeolite. The efficiency of nitrification and COD were very stable as about 95% and 80%, respectively. And critical flux was 128.8L/$m^{2}$/hr. The result of biodegradability test was following values at the each mode : Ss+Xs/$C_{T}$=81.7%, 35.1% and 45.3%, $X_{I}+S_{I}/C_{T}=18.3%$, 64.9% and 54.7%. When particulate matters such as $X_{I}$ and $X_{S}$ in influent are increased, membrane fouling will take place more and more. A relative ratio of filtration resistance to the fouling occurred by the cake layer was increased when increased the portion of $X_{I}$ and polysaccharide. It was thought that the formation of cake layer was promoted due to bond between $X_{I}$ and vicid material s generated from the polysaccharide.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.173-180
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• 1988

Chromosomal gene transferable hybrid plasmids, RP4::Mu cts and RP4::mini-Mu, were transferred by conjugation from E. coli to Pseudomonas strains. In order to use for recipient cells of RP4::Mu cts and RP4:: mini-Mu, plasmid-free Pseudomonas strains were characterized for their antobiotic resistance, aromatic hydrocarbon utility and degradation patterns of chlorinated herbicide. Transfer frequencies of RP4::mini-Mu exhibited about $10^{-2}$ to $10^{-4}$, while those of RP4::Mu cts exhibited very low value of $10^{-7}$ in recipients tested except Pseudomonas aeruginosa KU557. Existance of hybrid plasmids in Pseudomonas transconjugants were identified by their antibiotic resistance and agarose gel electrophoresis. In case of RP4::Mu cts transconjugants it was also confirmed by demonstrating that they were capable of releasing phage and forming plaques at $43^{\circ}C$. Plaque forming unit of the transconjugants was about $10^{5}$. It was shown by the stability test that RP4::Mu cts and RP4::mini-Mu in Pseudomonas were relatively stable.

• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.147-153
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• 2012

Precise estimation f a structure's dynamic characteristics is indispensable for ensuring stable dynamic response during life time especially for the structures which can experience resonance such as railway bridges. Especially, concrete track can change the modal properties of the railway bridge, through the contribution of stiffness as well as mass effects, generally only the mass effect is considered in dynamic analysis of the railway bridge. In this paper, static and dynamic behaviors of railway bridge with concrete track were investigated through experimental study. Also, numerical analysis was performed about considering only mass of concrete track and together with stiffness and mass of concrete track. These were compared with experiment value. Numerical analysis value considering together with stiffness and mass of concrete track was similar experiment value. Therefore, when dynamic analysis of railway bridge with concrete track is performed, the contribution of stiffness as well as mass effects for concrete track is considered.

• Korean Business Review
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• v.11
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• pp.439-464
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• 1998

Global electronic commerce, driven by the development of the Internet and computer, premises to be an important engine for growth for the world economy in the 21st century. Electronic commerce offers considerable new opportunities for businesses and citizens in all regions of the world by enhancing productivity across all sectors 6f our economies and encouraging trade in both goods and services. Specially in relation to contract, electronic commerce requires a coherent, coordinated approach internationally on key issues such as a validity, a legality, consumer protection. In order to ensure the stable growth of electronic commerce in Korea, the government needs to construct a predictable legal and commercial environment, suitable to the situation in Korea, for business conduct on the Internet and other electronic method. Electronic commerce, which breaks down national boundaries and widens the gap between the place where services are performed and the place where they are consumed, requires a new paradigm when making an agreement between contracting parties.

• Journal of the Korean Ceramic Society
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• v.38 no.5
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• pp.405-411
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• 2001

Compacts of a mixture of fine $\alpha$-Si$_3$N$_4$powders, 6% $Y_2$O$_3$and 1% $Al_2$O$_3$were attrition milled time on phase and microstructural development in silicon nitride ceramics. The sintered surface and the interior showed different behaviors in phase and microstructral developments. Increased oxygen content with increased milling time of powder mixture leads to the formation of Si$_2$$N_2$O phase at temperatures as low as 155$0^{\circ}C$. Si$_2$$N_2$O is stable in the interior of the samples but unstable in the surface region of the specimen sintered at higher temperature. This results in a duplex structure where the interior consists of Si$_2$$N_2$O grains dispersed in $\beta$-Si$_3$N$_4$matrix and a surface which contains only $\beta$-Si$_3$N$_4$. The alpha to beta phase transformation and the microstructural development are shown to be influenced by the formation and decomposition of the Si$_2$$N_2$O.