• Title/Summary/Keyword: Variety Chung

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Regulation of $Ca^{2+}$ Influx by Membrane Potential in Microglia

  • Lee, Jungsun;Uhm, Dae-Yong;Sungkwon Chung
    • Proceedings of the Korean Biophysical Society Conference
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    • 2002.06b
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    • pp.39-39
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    • 2002
  • Microglia are known to have an important function as brain macrophage during immunological processes, oncogenesis, and regeneration in the central nervous system (CNS). A wide variety of ion channels have been identified and characterized in microglia including inward rectifier $K^{+}$ channel (Kir), voltage dependent $K^{+}$ channel (Kv), $Ca^{2+}$-release activated $Ca^{2+}$ channel (CRAC).(omitted)

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DOUBLE LINES IN THE QUINTIC DEL PEZZO FOURFOLD

  • Kiryong Chung
    • Bulletin of the Korean Mathematical Society
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    • v.60 no.2
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    • pp.485-494
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    • 2023
  • Let Y be the quintic del Pezzo 4-fold defined by the linear section of Gr(2, 5) by ℙ7. In this paper, we describe the locus of double lines in the Hilbert scheme of coincs in Y. As a corollary, we obtain the desigularized model of the moduli space of stable maps of degree 2 in Y. We also compute the intersection Poincaré polynomial of the stable map space.

Mobility-Aware Interference Avoidance Scheme for Vehicular WLANs

  • Park, Lai-Hyuk;Na, Woong-Soo;Lee, Gun-Woo;Lee, Chang-Ha;Park, Chang-Yun;Cho, Yong-Soo;Cho, Sung-Rae
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.5 no.12
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    • pp.2272-2293
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    • 2011
  • Communication technology of future networks is predicted to provide a large variety of services including WiFi service in vehicular network. In this paper, we assume that vehicles are embedded with WiMAX antenna and in-vehicle terminals receive WiMAX traffic through WiFi interface. This assumption will impose severe performance degradation due to interference among mobile BSSs when WiFi access points (APs) are densely located. Existing interference avoidance techniques cannot properly resolve the above problems and do not cope with dynamically moving vehicular scenario since they focus only on the fixed network topology. In this paper, we propose a mobility-aware interference avoidance scheme for WiFi services. The proposed scheme computes the interference duration by exploiting mobility vector and location information of neighboring APs. If the interference duration is not negligible, our scheme searches for another channel in order to avoid interference. However, if the interference duration is negligible, our scheme continues to use the channel to reduce switching overhead. To measure the effectiveness of the proposed scheme against other existing techniques, we evaluated performance by using OPNET simulator. Through the simulation, we obtained about 60% reduction in the maximum interference frequency and about 67% improvement in throughput. Furthermore, our scheme provides fair channel usage.

Influence of Exposure to Extremely Low Frequency Magnetic Field on Neuroendocrine Cells and Hormones in Stomach of Rats

  • Hong, Min-Eui;Yoon, Kyu-Hyun;Jung, Yoon-Yang;Lee, Tae-Jin;Park, Eon-Sub;Sohn, Uy-Dong;Jeong, Ji-Hoon
    • The Korean Journal of Physiology and Pharmacology
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    • v.15 no.3
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    • pp.137-142
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    • 2011
  • Extremely low frequency magnetic fields (ELF-MF) have the ability to produce a variety of behavioral and physiological changes in animals. The stomach, as the most sensitive part of the neuroendocrine organ of the gastrointestinal tract, is crucial for the initiation of a full stress response against all harmful stress. Thus, the purpose of this study was to examine whether ELF-MF stimuli induce changes in the activity of neuroendocrine cells, considering their involvement in endocrine or paracrine effect on surrounding cells. The exposure to ELF-MF (durations of 24 h and 1 or 2 weeks, 60 Hz frequency, 0.1 mT intensity) altered the distribution and occurrence of gastrin, ghrelin and somatostatinpositive endocrine cells in the stomach of rats. The change, however, in the secretion of those hormones into blood from endocrine cells did not appear significantly with ELF-MF exposure. Comparing with sham control, ELF-MF exposure for 1 and 2 week induced an increase in $BaSO_4$ suspension propelling ratio of gastrointestinal tract, indicating that ELF-MF affects gastrointestinal motility. Our study revealed that ELF-MF exposure might influence the activity of endocrine cells, an important element of the intrinsic regulatory system in the digestive tract. The pathophysiological character of these changes and the mechanism responsible for neuroendocrine cell are still unclear and require further studies.

Molecular Modeling of Complexation Behavior of p-tert-Butylcalix[5]arene Derivative toward Butylammonium Ions

  • Choe, Jong-In;Chang, Suk-Kyu
    • Bulletin of the Korean Chemical Society
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    • v.23 no.1
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    • pp.48-52
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    • 2002
  • Using several molecular modeling programs we have performed computer simulations to investigate the complexation behaviors of an ester derivative of p-tert-butylcalix[5]arene (1e) toward a variety of butylammonium ions. Semi-empirical AM1 method was used for calculating the binding energies and the formation enthalpies. MM and CVFF forcefields for molecular mechanics calculations were adapted to express the complexation energies of the host. Molecular dynamics were performed to the calculated complex systems to simulate the ionophoric behavior of the host-guest complexes. The absolute Gibbs free energies of the host (1e) complexed with four kinds of butylammonium ions have been calculated using the Finite Difference Thermodynamic Integration (FDTI) method in Discover. Calculation results show that the trend in complex formation is n-$BuNH_3^+$ > iso-$BuNH_3^+$ >> sec-$BuNH_3^+$ > tert-$BuNH_3^+$, which is in good agreement with the experimental results.

Shadow and Highlight Invariant Color Models

  • Lee, Ja-Yong;Kang, Hoon
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.557-560
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    • 2005
  • The color of objects varies with changes in illuminant color and viewing conditions. As a consequence, color boundaries are influenced by a large variety of imaging variables such as shadows, highlights, illumination, and material changes. Therefore, invariant color models are useful for a large number of applications such as object recognitions, detections, and segmentations. In this paper, we propose invariant color models. These color models are independent of the object geometry, object pose, and illumination. From these color models, color invariant edges are derived. To show the validity of the proposed invariant color models, some examples are given.

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