• Journal of Ginseng Research
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• v.24 no.1
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• pp.18-22
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• 2000

In previous reports we have shown that ginsenosides inhibit high threshold voltage-dependent $Ca^{2+}$ channels in neuronal cells. However, these studies did not show whether ginsenosides-induced inhibition of $Ca^{2+}$ currents discriminates among the various $Ca^{2+}$ channel subtypes, although it is known that there are at least five different $Ca^{2+}$ channel subtypes in neuronal cells. In this study we investigated the effect of ginsenosides on high threshold voltage-dependent $Ca^{2+}$ channel subtypes using their selective $Ca^{2+}$ channel blockers nimodipine (L-type), $\omega$-conotoxin GVIA (N-type), or $\omega$-agatoxin IVA (P-type) in bovine chromaffin cells. We could observe that ginsenosides inhibited high threshold voltage-dependent $Ca^{2+}$ currents in a dose-dependent manner. The $IC_{50}$/ was about 120 $\mu$g/ml. Nimodipine had no effect on ginsenosides response. However, the effect of ginsenosides on $Ca^{2+}$ currents was reduced by $\omega$-conotoxin GVIA, $\omega$-agatoxin IVA, and mixture of nimodipine, $\omega$-contoxin GVIA, and $\omega$-agatoxin IVA. These data suggest that ginsenosides are negatively coupled to three types of calcium channels in bovine chromaffin cell, including an $\omega$-conotoxin GVIA-sensitive (N-type) channel, an $\omega$-agatoxin IVA-sensitive (P-type) channel and nimodipine/$\omega$-conotoxin GVIA/$\omega$-agatoxin IVA-resistant (presumptive Q-type) channel.Q-type) channel.

• Journal of the Chungcheong Mathematical Society
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• v.23 no.1
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• pp.11-27
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• 2010

Let $\Omega$ be a domain with smooth boundary in ${\mathbb{C}}^{n+1}$ and let $p{\in}{\partial}{\Omega}$. Suppose that $\Omega$ is Kobayashi hyperbolic and p is of Catlin multi-type ${\tau}=({\tau}_0,{\ldots},{\tau}_n)$. In this paper, we show that $\Omega$ admits a $C^{k}$ contraction at p with $k{\geq}\mid{\tau}\mid+1$ if and only if $\Omega$ is biholomorphically equivalent to a domain defined by a weighted homogeneous polynomial.

• Bulletin of the Korean Mathematical Society
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• v.52 no.5
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• pp.1683-1709
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• 2015

Let (${\Omega}$, S) be an association scheme where ${\Omega}$ is a non-empty finite set and S is a partition of ${\Omega}{\times}{\Omega}$. For a positive integer k we say that (${\Omega}$, S) is k-equivalenced if each non-diagonal element of S has valency k. In this paper we focus on 4-equivalenced association schemes, and prove that they are transitive.

• East Asian mathematical journal
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• v.27 no.3
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• pp.373-380
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• 2011

In this paper L-fuzzy ${\omega}$-closed and L-fuzzy ${\omega}$-open sets are introduced. Also a new class of L-fuzzy topological space called L-fuzzy ${\omega}$-basically disconnected space is introduced. Several characterizations and some interesting properties are also given.

• Korean Journal of Mathematics
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• v.24 no.3
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• pp.545-565
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• 2016

In this paper, we present some general results on the pointwise convergence of the non-convolution type nonlinear singular integral operators in the following form: $$T_{\lambda}(f;x)={\large\int_{\Omega}}K_{\lambda}(t,x,f(t))dt,\;x{\in}{\Psi},\;{\lambda}{\in}{\Lambda}$$, where ${\Psi}$ = and ${\Omega}$ = stand for arbitrary closed, semi-closed or open bounded intervals in ${\mathbb{R}}$ or these set notations denote $\mathbb{R}$, and ${\Lambda}$ is a set of non-negative numbers, to the function $f{\in}L_{p,{\omega}}({\Omega})$, where $L_{p,{\omega}}({\Omega})$ denotes the space of all measurable functions f for which $\|{\frac{f}{\omega}}\|^p$ (1 ${\leq}$ p < ${\infty}$) is integrable on ${\Omega}$, and ${\omega}:{\mathbb{R}}{\rightarrow}\mathbb{R}^+$ is a weight function satisfying some conditions.

• Archives of Pharmacal Research
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• v.17 no.3
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• pp.135-138
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• 1994

Acyclonucleoside homologues of 1-$(\omega$-cyabnoalkyl)-and 1, 3-bis $(\omega$-cyanoalkyl) uracils were synthesized by the series of alkylation reactions of uracil with the $\omega$-chloroalkyl nitrile ${(Cl-(CH}_2)_n$-CN;n=1, 2, 3, 4) in DMSO under $50-70^circ{C}$ temperature. The 1-$(\omega$-cyanoalkyl)-and 1, 3-bis$(\omega$-cyanoalkyl) uracils were separated either by the fractional crystallization or column chromatography. The antitumor activities for these synthesized compounds were determined against four cell lines (J-82 cell, P388 cell, FM-3A cell and U-937 cell lines). These compounds failed to exhibit any significant antitumor activity.

• Journal of the Korean Applied Science and Technology
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• v.18 no.1
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• pp.67-77
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• 2001

In search for several fatty acid with unusual structure in vegetable oils, we have found that unknown peaks were shown on GLC in the analysis of fatty acids of the lipids from the pulp of ripened jujube (Zizypus jujuba var. inermis) fruits. These fatty acids were identified as a series of cis-monoenoic acids with ${\omega}-5$ double bond system such as $C_{14:1{\omega}5}$, $C_{16:1{\omega}5}$ and $C_{18:1{\omega}5}$, including ${\omega}-7$ fatty acid as $C_{16:1{\omega}7}$ and $C_{18:1{\omega}7}$, by GLC, solid-phase extraction silver ion-column chromatographic, GLC-mass spectrometric and IR techniques. First of all, total fatty acid methyl esters were resolved into saturated and branched fatty acid, monoenoic acid, dienoic acid, and trienoic acid fraction, respectively, with 100% dichloromethane (DCM), DCM/acetone (9:1, v/v) 100% acetone, and acetone/ acetonitrile (97:3, v/v) solvent system. Unknown fatty acids were included in the monoenoic fraction and were confirmed to have cis-configuration by IR. Picolinyl esters of monoenoic fatty acids gave distinct molecular ion peak and dominant diagnostic peaks, for example, m/z 317, 220 and 260 fragment for $cis-C_{14:1{\omega}5}$, m/z 345, m/z 248 and 288 fragment for $cis-C_{16:1{\omega}5}$ and m/z 373, m/z 276 and 316 fragment for $cis-C_{18:1{\omega}5}$. In this way the occurrence of $cis-C_{16:1{\omega}7}$ and $cis-C_{18:1{\omega}7}$ could be deduced from the appearance of prominent fragments as m/z 345, 220 and 260, and m/z 373, 248 and 280. Level of total ${\omega}-5$ fatty acids amounted to about 30% in the fatty acid composition with the predominance of $C_{16:1{\omega}5}$ $ (18.7{\sim}25.0%)$, in the semi-ripened and/or ripened samples collected in September 14 ($C_{16:1{\omega}5}$ ; 18.7%, $C_{14:1{\omega}5}$ ; 3.6% and $C_{18:1{\omega}5}$ ; 3.0%), September 22 ($C_{16:1{\omega}5}$ ; 25.0%, $C_{14:1{\omega}5}$ ; 1.4% and $C_{18:1{\omega}5}$ ; 2.6%), and October $7 (C_{16:1{\omega}5}$ ; 24.7%, $C_{14:1{\omega}5}$ ; 7.7% and $C_{18:1{\omega}5}$ ; 2.5%). However, the lipids extracted from unripened jujube in July and August contain these unusual fatty acids as low as negligible. It could be observed that the level of ${\omega}-5$ fatty acids in the pulps increased sharply with an elapse of ripening time of jujube fruits. Other monoenoic fatty acids with ${\omega}-7$ series, $C_{16:1{\omega}7}$ (palmitoleic acid) and $C_{18:1{\omega}7}$ (cis-vaccenic acid) could be detected. And in the lipids of the kernel and leaf of jujube, none of ${\omega}-5$ fatty acids could be detected.

• Structural Engineering and Mechanics
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• v.25 no.4
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• pp.481-500
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• 2007

The dynamic instability of doubly curved panels, subjected to non-uniform tensile in-plane harmonic edge loading $P(t)=P_s+P_d\;{\cos}{\Omega}t$ is investigated. The present work deals with the problem of the occurrence of combination resonances in contrast to simple resonances in parametrically excited doubly curved panels. Analytical expressions for the instability regions are obtained at ${\Omega}={\omega}_m+{\omega}_n$, (${\Omega}$ is the excitation frequency and ${\omega}_m$ and ${\omega}_n$ are the natural frequencies of the system) by using the method of multiple scales. It is shown that, besides the principal instability region at ${\Omega}=2{\omega}_1$, where ${\omega}_1$ is the fundamental frequency, other cases of ${\Omega}={\omega}_m+{\omega}_n$, related to other modes, can be of major importance and yield a significantly enlarged instability region. The effects of edge loading, curvature, damping and the static load factor on dynamic instability behavior of simply supported doubly curved panels are studied. The results show that under localized edge loading, combination resonance zones are as important as simple resonance zones. The effects of damping show that there is a finite critical value of the dynamic load factor for each instability region below which the curved panels cannot become dynamically unstable. This example of simultaneous excitation of two modes, each oscillating steadily at its own natural frequency, may be of considerable interest in vibration testing of actual structures.

• Journal of Sensor Science and Technology
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• v.3 no.3
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• pp.3-8
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• 1994

Flow sensor was fabricated with PTC thermistor usually operating as thermostats. The PTC thermistor was manufactured with $(Ba_{0.7}Sr_{0.3})TiO_{3}$ powder and its resistivity as a function of flow velocity was investigated. The resistivity changed from 4.45 $k{\Omega}{\cdot}cm$ to 3.95 $k{\Omega}{\cdot}cm$ as flow velocity varied 0 cm/s to 5 cm/s The sensitivities of the PTC thermistor were -204 (${\Omega}{\cdot}cm$)/(cm/s) and -24 (${\Omega}{\cdot}cm$)/(cm/s) at the flow velocity of 1 cm/s and 5 cm/s, respectively.

• Bulletin of the Korean Mathematical Society
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• v.52 no.4
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• pp.1123-1132
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• 2015

In this paper, we investigate derivations on the noncommutative Banach algebra $L^{\infty}_0({\omega})^*$ equipped with an Arens product. As a main result, we prove the Singer-Wermer conjecture for the noncommutative Banach algebra $L^{\infty}_0({\omega})^*$. We then show that a derivation on $L^{\infty}_0({\omega})^*$ is continuous if and only if its restriction to rad($L^{\infty}_0({\omega})^*$) is continuous. We also prove that there is no nonzero centralizing derivation on $L^{\infty}_0({\omega})^*$. Finally, we prove that the space of all inner derivations of $L^{\infty}_0({\omega})^*$ is continuously homomorphic to the space $L^{\infty}_0({\omega})^*/L^1({\omega})$.