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Seoul, South Korea

Lee D.,Pohang University of Science and Technology | Lee S.-G.,Seoul Science High School | Kim S.,Pohang University of Science and Technology
European Physical Journal B | Year: 2012

The transmission of a signal through an axon is studied using a compartment model of a non-uniform axon. We find that the transmission efficiency in these axons has nonlinear mode-locking structure that depends on the relative ion channel density. The refractory period of the soma is found to be longer than that of its axon and this structure appears by it. Our study suggets that non-uniform axons can actively participate in information processing. © EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2012. Source


Shin J.,Seoul Science High School | Jeon S.,Seoul National University | Kim H.S.,Seoul National University | Yoo S.-W.,Seoul National University
Japanese Journal of Applied Physics | Year: 2015

In this paper, we analyzed the amplitude of variable junction leakage currents caused by the interaction between two interface states in MOS transistors. For the first time, an analytical equation for the ratio between the junction leakage current before and after electron capture into the slow state was derived with consideration of both the change in the capture cross-section and the electric field. Also, the correct equation for the electric field after electron trapping was derived and used. The distance between the two interface states was extracted from the equation and measurement data. The extracted distance was interpreted under the framework of the inter-atomic distance in the silicon lattice structure at the Si/SiO2 interface. © 2015 The Japan Society of Applied Physics. Source


Hahn C.,Hanyang University | Oh C.-H.,Hanyang University | Wang H.,Seoul Science High School
Journal of the Korean Physical Society | Year: 2011

A photonic crystal structure was fabricated by using a flow-controlled vertical deposition (FCVD) method. We simplified the fabrication setup by replacing the peristaltic pump with just an open hole at the bottom of beaker. The optimum surface drop velocity of the polystyrene suspension for a photonic crystal structure with uniform surface and thickness was experimentally determined to be 0.35 μm/s. The photonic band-gap behavior of the fabricated photonic crystal structure was analyzed by using the transmission spectrum. The measured transmission spectrum was compared with a theoretical calculation, and we learned that the particle size contracted during the selfassembly process. Source


Kim H.-R.,Ewha Womans University | Lee S.-M.,Ewha Womans University | Won J.-W.,Seoul Science High School | Lim W.,Ewha Womans University | And 3 more authors.
Immunology | Year: 2013

Regulatory T (Treg) cells are important in the regulation of immune response, but the exact regulation of Treg-cell function in vivo is still not well known. In the present study, we investigated the functional activity of CD4+ CD25+ Treg cells as well as the frequency and number of CD4+ CD25+ FoxP3+ Treg cells in the spleens of experimentally infected mice with a tissue-migrating parasite, sparganum (plerocercoid of Spirometra mansoni) for 3 weeks. The results demonstrated fluctuations in the Treg-cell function during the parasite infection, being up-regulated at day 3, down-regulated until day 14, and thereafter up-regulated again at day 21. We also investigated the cytokine-producing capability of the splenocytes to study the pattern of immune response of the mice to the parasite. The results showed decreased capabilities of interleukin-2 (IL-2), interferon-γ (IFN-γ) and IL-17α production, whereas IL-4-producing and IL-10-producing capabilities were increased along with the parasitic infection. Meanwhile, IL-6-producing capability was increased to reach a peak at week 2, and thereafter was decreased to the baseline level. As a regulatory mechanism, we found that Treg-cell function was attenuated in the presence of the crude extracts of sparganum, but was enhanced in the presence of the excretory-secretory products, suggesting that sparganum products were involved in the triggering and regulation of immune response in the acute and chronic phases, respectively. Results show that Treg cells are central in the immune homeostasis in vivo that is maintained by host-parasite interactions during the parasitic infection. © 2012 Blackwell Publishing Ltd. Source


Jung K.,Seoul Science High School | Cho W.,Wonkwang University
Analytical Chemistry | Year: 2013

Glycan-targeting affinity chromatography systems are becoming increasingly important as tools in the purification, enrichment, and identification of glycoproteins. The great advantage of this strategy is that immobilized lectin and antibody selectors allow specific glycan structures to be matched with a particular protein. It is also possible to show that a glycan seen at one site in a glycoprotein may not be present at another glycosylation site in the same glycoprotein. A problem with single-column affinity chromatography is how to obtain information on glycan diversity within the oligosaccharide portions of captured glycoproteins. Although all the glycoprotein species bearing a particular glycan feature will be captured by an affinity column, there is no way of knowing whether the ligand being targeted appears alone or coresides with a series of other glycan features in the same oligosaccharide conjugate. The work being described here examines the utility of serial affinity columns in determining whether individual glycan structures appear alone or together with other glycans in specific proteins. Four different types of affinity columns were examined in two series; the LEL → HPA → anti-LexAb → anti-sLexAb series and the anti-sLexAb → anti-LexAb → HPA → LEL series. Patterns in protein capture from these two series were very different. Thus, serial affinity chromatography (SAC) can be a valuable tool in recognizing diversity in protein glycosylation, especially when the order of columns in the SAC series is varied. Two clear types of diversity were recognized. One is the independent occurrence of different affinity-targetable glycan features in the same glycoprotein. The other is that multiple targetable glycan features were coresident in the same glycoprotein. The great advantage of this method is that it couples easily with current methods used in glycoproteomics. © 2013 American Chemical Society. Source

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