• BMB Reports
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• v.34 no.5
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• pp.408-414
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• 2001

Ornithine decarboxylase (EC 4.1.1.17) is an essential enzyme for polyamine synthesis and growth in mammalian cells and plants. We compared the biochemical and immunological properties of rat and Nicotiana glutinosa ODC by cloning and expressing the recombinant proteins. The primary amino acid sequence between rat and N. glutinosa ODC had a 40% homology The molecular weight of the overexpressed rat ODC was 53 kDa, and that of N. glutinosa was 46.5 kDa. Adding 1 mM of putrescine to the enzyme reaction mixture inhibited both rat and N. glutinosa ODC activity to 30%. Agmatine had an inhibitory effect only on N. glutinosa ODC. Cysteine and lysine modifying reagents reduced both ODC activities, verifying the key roles of cysteine and lysine residues in the catalytic mechanism of ODC. ELISA was performed to characterize the immunological difference between the rat and plant ODC. Both the rat and N. glutinosa ODC were recognized by the polyclonal antibody that was raised against purified N. glutinosa ODC, but the rat ODC was 50-fold less sensitive to the antibody binding. These results indicate that even though both ODCs have the same evolutionary origin, there seems to be a structural distinction between the species.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1320-1325
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• 2008

In the manufacture of automobile suspension modules at a company as parts supplier, the design process includes the detail design and the design modification via structural and fatigue durability analyses considering PoF(physics of failure) of their weldments that are repeated more than four times sequentially. The approval of the design and the release of final drawings follows. For the suspension modules, e.g. control arms and cross member, the man-hours per worker required in the process outlined above can reach as high as 1,414hours. Application of the developed integrated design system can reduce the man-hours of 1,004. In comparison with the conventional design process, this integrated design system reduces the required time by about 40%. If expense is taken into account, a savings of approximately $192,000 is estimated, assuming the design process accounts for 1.5% of total sales for the parts supplier

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.6
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• pp.736-752
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• 1995

Fine structural changes of germ cell during the gametogenesis of Korean rockfish, Sebastes schlegeli sampled in west coast of Korea were investigated from September 1993 to August 1994. In a layer of microvilli of oocyte with active yolk duplication, many pinocytotic vesicles containing protein granules regarded as yolk precursors were observed. The multivesicular bodies were formed by gathered mitochondria. They are participated in formation of the primary yolk globules homogeneously filled with high dense particles and enclosed within a limiting membrane. The precursors of yolk globule appeared to be formed by modification of mitochondria and they developed into the primary yolk globules with participation of large and dense pinocytotic vesicles. Yolk globules in mature oocyte were consisted of three components: the crystalline type main body, the superficial layer with dense and fine granules, and the limiting membrane. Steroid hormone secreting cells were recognized in the interstitial cells of growing testis. Numerous endoplasmic reticula and large mitochondria with well developed tubular cristae appeared in their cytoplasms. The axoneme in the tail flagellum of spermatozoon consisted of nine pairs of microtubules at the periphery and one pair at the center, and they were covered with doublet microtubules.

• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.188-191
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• 2005

Abstract Cyclosporins are a family of clinically-important immunosuppressive cyclic peptides produced by Tolypocladium inflatum. The structural modification of cyclosporins via hydroxylation at various positions of N-methyl leucines in cyclosporin A leads to a dramatic change of their bioactive spectra. Among over 100 soil actinomycetes screened, two actinomycetes species, Sebekia benihana and Pseudonocardia autotrophica, were identified to contain superior cyclosporin A hydroxylation activities. A HPLC-based cyclosporin A hydroxylation assay revealed that each strain possesses distinctive hydroxylation specificity and regiospecificity; mono-hydroxylation at the 4th N-methyl leucine of cyclosporin A by S. benihana, and di-hydroxylations at both 4th and 9th N-methyl leucines of cyclosporin A by P. autotrophica. The conversion yields for cyclosporin A hydroxylation by both S. benihana and P. autotrophica were significantly improved from less than 10% and 18% up to 58% and 45%, respectively, in the optimized culture containing molybdenum with 0.05 g/l of cyclosporin A concentration. An ancymidol-specific inhibition of cyclosporin hydroxylation also suggested that the regiospecific cyclosporin hydroxylation might be catalyzed by a putative cytochrome P450 mono-oxygenase enzyme.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.7
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• pp.634-641
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• 2008

Automatic Differentiation(AD) is a tool for generating sensitivities, such as gradient or Jacobian, automatically. AD tools provide mathematically exact sensitivities for the given source code. In this paper applications of automatic differentiation are studied. Derivative codes are generated with AD tools for structural analysis code and flow analysis code. How to apply AD tools is explained and the accuracy of sensitivities is compared with the finite difference. Sensitivities of generated derivative code accord well with finite difference, but the calculation time of derivative code increases. It was found that the calculation time can be decreased by additional modification of derivative code.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1051-1055
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• 2003

Aluminum carbody for rolling stocks is light and perfectly recycled, but includes severe defects which are very dangerous to fatigue strength. Structural integrity assessment for the carbody by static load test has been performed up to date. In this study, to evaluate fatigue strength of the aluminum carbody of urban transit unit. a testing method to simulate dynamic loading condition was proposed and the fatigue strength of the carbody was evaluated. The dynamic load test results showed that the alternating stress ranges were different from the estimated ranges based on the static test results. Excessive stress ranges at the center are thought to come from the flexible motion of the carbody. published fatigue test data for aluminum components, but variation of alternating acceleration along the length due to flexibility of carbody yielded unexpected results. Because fatigue strength based on the static test results may be overestimated at the center, modification of testing method is necessary.

• Applied Science and Convergence Technology
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• v.26 no.5
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• pp.133-138
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• 2017

We investigated the interface defect engineering and reaction mechanism of reduced transition layer and nitride layer in the active plasma process on 4H-SiC by the plasma reaction with the rapid processing time at the room temperature. Through the combination of experiment and theoretical studies, we clearly observed that advanced active plasma process on 4H-SiC of oxidation and nitridation have improved electrical properties by the stable bond structure and decrease of the interfacial defects. In the plasma oxidation system, we showed that plasma oxide on SiC has enhanced electrical characteristics than the thermally oxidation and suppressed generation of the interface trap density. The decrease of the defect states in transition layer and stress induced leakage current (SILC) clearly showed that plasma process enhances quality of $SiO_2$ by the reduction of transition layer due to the controlled interstitial C atoms. And in another processes, the Plasma Nitridation (PN) system, we investigated the modification in bond structure in the nitride SiC surface by the rapid PN process. We observed that converted N reacted through spontaneous incorporation the SiC sub-surface, resulting in N atoms converted to C-site by the low bond energy. In particular, electrical properties exhibited that the generated trap states was suppressed with the nitrided layer. The results of active plasma oxidation and nitridation system suggest plasma processes on SiC of rapid and low temperature process, compare with the traditional gas annealing process with high temperature and long process time.

• KIEAE Journal
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• v.12 no.1
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• pp.21-27
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• 2012

This study aims at finding the trend changes of spatial configuration in housing units of Korean apartments in the 2000s. Among the housing units in the apartments built by large construction companies, we have selected ones with small and regular sizes, $59m^2$ and $84m^2$ respectively, and investigated the number of bays, the location of wet zone and the spatial flexibility in the housing units selected for analysis. In conclusion, the number of bays in the housing unit has gradually increased, after allowing for the structural change of the balcony in the legal. It is estimated that the trend has came from the intent to increase the numbers of the externally exposed surfaces of the balcony, ensure a good view, lighting, ventilation and spatial flexibility. The location of wet zone, water-needed space such as a bathroom or a kitchen, has changed in the direction to facilitate the expansion and modification of space. Variable range of space has gradually expanded by using the balcony and wet zone as much as possible. In order to configure more effectively spaces in housing environments, the future study should be implemented to develop tools for realizing sustainable housing environment at the levels of not only the housing unit. but also the entire building, housing site, and city.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.3-23
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• 2017

The achievement of tissue engineering can be highly depending on the capability to generate complicated, cell seeded three dimensional (3D) micro/nano-structures. So, various fabrication techniques that can be used to precisely design the architecture and topography of scaffolding materials will signify a key aspect of multi-functional tissue engineering. Previous methods for obtaining scaffolds based on top-down are often not satisfactory to produce complex micro/nano-structures due to the lack of control on scaffold architecture, porosity, and cellular interactions. However, a bioprinting method can be used to design sophisticated 3D tissue scaffolds that can be engineered to mimic the tissue architecture using computer aided approach. Also, in recent, the method has been modified and optimized to fabricate scaffolds using various natural biopolymers (collagen, alginate, and chitosan etc.). Variation of the topological structure and polymer concentration allowed tailoring the physical and biological properties of the scaffolds. In this presentation, the 3D bioprinting supplemented with a newly designed plasma treatment for attaining highly bioactive and functional scaffolds for tissue engineering applications will be introduced. Moreover, various in vivo and in vitro results will show that the fabricated scaffolds can carry out their structural and biological functionality.

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.693-697
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• 2004

YH-1715R, (2R,3R)-2-(2,4-difluorophenyl)-3-(3-methoxy-1,2,4-isothiazol-3-yl-thio)-1-( 1H-1,2,4-triazol-l-yl)-2-butanol, a new triazole derivative obtained by the structural modification of fluconazole, was found to exhibit potent anti-Candida activity against a wide variety of Candida albicans (C. albicans) (MIC: 0.4-12.5 mg/l). To investigate the mode of action of YH-1715R, its effect on ergosterol biosynthesis in cell-free extracts and whole cells of C. albicans was examined. The inhibitory activity of YH-1715R was approximately ten-fold higher than that of fluconazole. To determine the primary action mechanism of YH-1715R, its inhibitory activity against lanosterol $14\alpha$-demethylase (14$\alpha$-DM), a major target for azole, was measured using gas-liquid chromatography. YH-1715R and fluconazole were found to inhibit 14a-DM with an $IC_{50}$ of 0.015 $\mu$M and 0.01$8\mu$M, respectively, plus the mode of inhibition of YH-1715R and fluconozole was noncompetitive with a $K_i$ of 0.0533$\mu$M and 0.0975$\mu$M.