• Title/Summary/Keyword: Lee Soon-Sin

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Benzoin Condensation Reactions of 5-Membered Heterocyclic Compounds Catalyzed by Thiazolium Salts

  • Chang Kiu Lee;Jin Soon Gong;Sin Kwan Seog;Jong-Gab Jun
    • Bulletin of the Korean Chemical Society
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    • v.14 no.1
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    • pp.29-31
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    • 1993

  • Benzoin condensation reactions of furfurals and thiophenecarboxaldehydes in the presence of substituted benzyl and alkyl thiazolium salts were examined in order to improve the yield of the reaction and to examine the effect of the electronic nature of the catalysts. Thiophene derivatives gave thenils as the major products in low yields while furan derivatives gave only furoins in moderate to high yields.

  • https://doi.org/10.5012/bkcs.1993.14.1.29 인용 PDF

The Effect of NO Donor on Contraction, Cytosolic $Ca^{2+}$ Level and Ionic Currents in Guinea-pig Ileal Smooth Muscle

  • Kwon, Seong-Chun;Park, Ki-Young;Ahn, Duck-Sun;Lee, Young-Ho;Kang, Bok-Soon
    • The Korean Journal of Physiology and Pharmacology
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    • v.4 no.1
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    • pp.33-40
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    • 2000

  • This study was designed to clarify the mechanism of the inhibitory action of a nitric oxide (NO) donor, 3-morpholino-sydnonimine (SIN-1), on contraction, cytosolic $Ca^{2+}$ level $([Ca^{2+}]_i)$ and ionic currents in guinea-pig ileum. SIN-1 $(0.01{\sim}100\;{\mu}M)$ inhibited 25 mM KCl- or histamine $(10\;{\mu}M)-induced$ contraction in a concentration-dependent manner. SIN-1 reduced both the 25 mM KCl- and the histamine-stimulated increases in muscle tension in parallel with decreased $[Ca^{2+}]_i.$ Using the patch clamp technique with a holding potential of -60 mV, SIN-1 $(10\;{\mu}M)$ decreased peak Ba currents $(I_{Ba})$ by $30.9{\pm}5.4%$ (n=6) when voltage was stepped from -60 mV to +10 mV and this effect was blocked by ODQ $(1\;{\mu}M),$ a soluble guanylyl cyclase inhibitor. Cu/Zn SOD (100 U/ml), the free radical scavenger, had little effect on basal $I_{Ba},$ and SIN-1 $(10\;{\mu}M)$ inhibited peak $I_{Ba}$ by $32.4{\pm}5.8%$ (n=5) in the presence of Cu/Zn SOD. In a cell clamped at a holding-potential of -40 mV, application of $10\;{\mu}M$ histamine induced an inward current. The histamine-induced inward current was markedly and reversibly inhibited by $10\;{\mu}M$ SIN-1, and this effect was abolished by ODQ $(1\;{\mu}M).$ In addition, SIN-1 markedly increased the depolarization-activated outward $K^+$ currents in the all potential ranges. We concluded that SIN-1 inhibits smooth muscle contraction mainly by decreasing $[Ca^{2+}]_i$ resulted from the inhibition of L-type $Ca^{2+}$ channels and the inhibition of nonselective cation currents and/or by the activation of $K^+$ currents via a cGMP-dependent pathway.

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Current Development Status of Payload Data Handling Unit for Earth Observation Satellite (지구관측 위성용 탑재체자료처리장치 개발 동향)

  • Lee, Jong-Tae;Lee, Sang-Gyu;Yong, Sang-Soon;Yi, Ho-Sang;Lee, Seung-Kun;Song, Jin-Huan;Kwak, Sin-Ung
    • Current Industrial and Technological Trends in Aerospace
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    • v.9 no.1
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    • pp.90-101
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    • 2011

  • In this article, we introduce the technologies and trend of technical evolution of Payload Data Handling Unit (PDHU) for Earth Observation Satellites. As well, we review the efforts for the Koreanization of PDHU so far, and conclude with some suggestions for future work.

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