• Communications of the Korean Mathematical Society
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• v.34 no.3
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• pp.743-755
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• 2019

For every inverse semigroup S with subsemigroup E of idempotents, necessary and sufficient conditions are obtained for the weighted semigroup algebra $l^1(S,{\omega})$ and its second dual to be $l^1(E)$-module amenble. Some results for the module Arens regularity of $l^1(S,{\omega})$ (as an $l^1(E)$-module) are found. If S is either of the bicyclic inverse semigroup or the Brandt inverse semigroup, it is shown that $l^1(S,{\omega})$ is module amenable but not amenable for any weight ${\omega}$.

• Communications of the Korean Mathematical Society
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• v.38 no.3
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• pp.787-805
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• 2023

Let (Ω, µ) be a measure space and {τ_α}_α∈Ω be a normalized continuous Bessel family for a finite dimensional Hilbert space 𝓗 of dimension d. If the diagonal ∆ := {(α, α) : α ∈ Ω} is measurable in the measure space Ω × Ω, then we show that $$\sup\limits_{{\alpha},{\beta}{\in}{\Omega},{\alpha}{\neq}{\beta}}\,{\mid}{\langle}{\tau}_{\alpha},\,{\tau}_{\beta}{\rangle}{\mid}^{2m}\,{\geq}\,{\frac{1}{({\mu}{\times}{\mu})(({\Omega}{\times}{\Omega}{\backslash}{\Delta})}\;\[\frac{{\mu}({\Omega})^2}{\({d+m-1 \atop m}\)}-({\mu}{\times}{\mu})({\Delta})\],\;{\forall}m{\in}{\mathbb{N}}.$$ This improves 48 years old celebrated result of Welch [41]. We introduce the notions of continuous cross correlation and frame potential of Bessel family and give applications of continuous Welch bounds to these concepts. We also introduce the notion of continuous Grassmannian frames.

• Journal of the Korean Mathematical Society
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• v.54 no.3
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• pp.1015-1030
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• 2017

This paper is concerned with the following Klein-Gordon-Maxwell system: $$\{-{\Delta}u+{\lambda}V(x)u-(2{\omega}+{\phi}){\phi}u=f(x,u),\;x{\in}\mathbb{R}^3,\\{\Delta}{\phi}=({\omega}+{\phi})u^2,\;x{\in}\mathbb{R}^3$$ where ${\omega}$ > 0 is a constant and ${\lambda}$ is the parameter. Under some suitable assumptions on V (x) and f(x, u), we establish the existence and multiplicity of nontrivial solutions of the above system via variational methods. Our conditions weaken the Ambrosetti Rabinowitz type condition.

• Journal of the Korean Mathematical Society
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• v.45 no.3
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• pp.645-681
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• 2008

The Navier-Stokes system for heat-conducting incompressible fluids is studied in a domain ${\Omega}{\subset}R^3$. The viscosity, heat conduction coefficients and specific heat at constant volume are allowed to depend smoothly on density and temperature. We prove local existence of the unique strong solution, provided the initial data satisfy a natural compatibility condition. For the strong regularity, we do not assume the positivity of initial density; it may vanish in an open subset (vacuum) of ${\Omega}$ or decay at infinity when ${\Omega}$ is unbounded.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.642-646
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• 1989

We have developed analysis program of discharge chracteristics of KrF laser system with charge transfer type, that studied about deposited energy, nonlinear discharge, and electron number density in the laser tube. With this program, voltagr, current, and deposited energy was calculated 27 KV,32.6 KA,200 MW at total pressure 2 atm and charging voltage 33 KV, respectively. At this condition, circuit parameters are L1=150nH, R1=$0.3{\Omega}$, L2=15nH, R2= $0.3{\Omega}$. In addition, nonlinear discharge resistance and electron number density was calculated ${\infty}{\sim}0.17{\Omega}.1{\times}10^{16}cm^{-3}$, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.4
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• pp.550-555
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• 1995

This study was conducted to investigate the prevalence of obesity and the concerns with omega 3 fatty acid intakes in 100 men do regular exercising. Most subjects were 23~66 years old whose average height and weight were 170.0$\pm$0.5cm and 68.2$\pm$0.8kg, respectively. Prevalence of obesity was 7%, 41% and 41% by criteria of Bioelectrical impedance analysis, Skin fold thickness and Body mass index, respectively. According to this survey, 75% of the subjects prefered vegetable oil to animal fat, 55% of them prefered seaweeds to shellfishes and 76% of them prefered natural foods to processed foods for good health. 61% of the interviewed subjects had the experience of eating perilla oil and 49% of them chose the Mackeral that had contained omega 3 fatty acids. The reason that seaweeds were good for health was rather high vitamin and mineral content than low fat.

• Biomedical Science Letters
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• v.14 no.3
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• pp.187-192
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• 2008

To clerify the protective effect of omega-3 of polyunsaturated fatty acid docosahexaenoic acid (DHA) on the cytotoxicity induced by organic mercury in cultured NIH3T3 fibroblasts. The measurement of cell viability on ogranic mercury wad done by XTT assay after NIH3T3 fibroblasts were cultured with various concentrations of methyl mercuric chloride (MMC). And also, the effect of DHA on the MMC-mediated cytotoxicity was examined by cell viability, and antioxidant effect of DHA was also assessed by superoxide dismutase (SOD)-like activity and the lipid peroxidation activity in cultured NIH3T3 fibroblasts. In this study, MMC decreased cell viability and $XTT_{50}$ value was determined at $50{\mu}M$ of MMC in these culture. In the effect of DHA against the cytotoxicity induced by MMC, DHA significantly increased the cell viability damaged by MMC in cultured NIH3T3 fibroblasts. And also, DHA showed the antioxidant effect by showing the increase of SOD-like activity and the decrease of lipid peroxidation activity. From these results, it is suggested that organic mercury such as MMC has highly toxic effect on cultured NIH3T3 fibroblasts, and also, omega-3 of polyunsaturated fatty acid, DHA showed the protection on MMC-induced cytotoxicity and antioxidant effect.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.2
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• pp.87-91
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• 2002

The aim of this study was to investigate the role of $Ca^{2+}-channel$ blockers in norepinephrine (NE) release from rat hippocampus. Slices and synaptosomes were incubated with $[^3H]-NE$ and the releases of the labelled products were evoked by 25 mM KCl stimulation. Nifedipine, diltiazem, nicardipine, flunarizine and pimozide did not affect the evoked and basal release of NE in the slice. But, diltiazem, nicardipine and flunarizine decreased the evoked NE release with a dose-related manner without any change of the basal release from synaptosomes. Also, a large dose of pimozide produced modest decrement of NE release. ${\omega}-conotoxin$ (CTx) GVIA decreased the evoked NE release in a dose-dependent manner without changing the basal release. And ${\omega}-CTxMVIIC$ decreased the evoked NE release in the synaoptosomes without any effect in the slice, but the effect of decrement was far less than that of ${\omega}-CTxGVIA.$ In interaction experiments with ${\omega}-CTxGVIA,\;{\omega}-CTxMVIIC$ slightly potentiated the effect of ${\omega}-CTxGVIA$ on NE release in the slice and synaptosomal preparations. These results suggest that the NE release in the rat hippocampus is mediated mainly by N-type $Ca^{2+}-channels,$ and that other types such as L-, T- and/or P/Q-type $Ca^{2+}-channels$ could also be participate in this process.

• Journal of the East Asian Society of Dietary Life
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• v.4 no.1
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• pp.57-70
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• 1994

The present study was carried out in normal and atherosclerotic New Zealand white(NZW) rabbits, to evaluate the effect of dietary supplementation with Korean pinenut oil, on the total fatty acid composition of red blood cell membranes. Erythrocyte fatty acids of chain lengths ranging fro 12 : 0 to 22 : 6$\omega$3 were identified. In study I, palmitic acid(16 : 0) was found to be the main erythrocyte membranes fatty acid, followed in turn by stearic(18 : 0), oleic(18 : 1), and linoleic acids(18 : 2$\omega$6). There was a large increase in the proportion of 20 : 4$\omega$6 in 10% pinenut oil group on days 40 and 80(compared with control), although the increase was not statistically significant. Most erythrocyte fatty acids were less affected by the types or levels of oils supplemented for periods fo 40 and 80days. In study II,at the end of the dietary treatment, the levels of 12 : 0, 14 : 0, 15 : 0 and 18 : 0 were significantly decreased in the 5% soybean oil/cholesterol group, whereas those of 12 : 0, 14 : 0 and 18 : 0 were significantly decreased, but that of 18 : 2$\omega$6 was significantly increased in the 10% soybean oil/cholesterol group, compared to the cholesterol group. No significant differences in fatty acid composition were seen between the pinenut oil/cholesterol group, whereas the 10% soybean oil/cholesterol group had significantly elevated 18 : 2$\omega$6, compared to the cholesterol group. The proportion of 18 : 4$\omega$6 was significantly raised in the 5% soybean oil/cholesterol and 5% pinenut oil/cholesterol group, and the content of 16 : 1$\omega$7 was significantly lowered in the 5% and 10% soybean/cholesterol groups, compared to the cholesterol group at 10 weeks supplementation. In studies I,II and III, the total proportions of saturated fatty acids were not significantly affected by the types of levels of oils supplemented throughout the study period.

• Journal of Nutrition and Health
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• v.26 no.2
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• pp.131-144
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• 1993

This study was carried out to investigate the effects of different sources and level of dietary lipid on lecithin : cholesterol acyltrasferase activity and cholesterol metabolism in male rats of Sprague-Dawley strain. The effects of different lipid sources was compared with sardine oil($\omega$3 EPA and DHA), beef tallow(SFA), perilla oil($\omega$3 linolenic acid) and corn oil($\omega$6 linoleic acid). Diets were formulated in such a way that 10%, 20% and 40% dietary energy were supplied with each of four experimental lipid sources. Control diet contained only non-lipid energy. A total number of 78 rats, equally divided into 13 groups, were fed the experimental diets for a period of 6 weeks. In vitro cultures were also carried out to study the cholesterol synthetic activity in the liver prepared from rats used in feeding trials. The concentration of plasma total cholesterol, HDL-cholesterol, LDL-cholesterol and HDL-C/T/C(total cholesterol) ratio were significantly (p<0.001) influenced by dietary lipid sources. Higher HDL-cholesterol and lower LDL-cholesterol concentration in plasma were obtained in rats fed $\omega$3 fatty acid supplemented diets(sardine oil and perilla oil group) compared to diets containing $\omega$6 and saturated fatty acid(corn oil and beef tallow group). In total cholesterol concentration of plasma, beef tallow group was significantly (p<0.001) higher than other lipid groups, and non-lipid group was significantly(p<0.05) higher than the lipid supplemented groups. The activity of lecithin : cholesterol acyltransferase(LCAT) in plasma was greatly(p<0.001) affected by dietary lipid sources and levels. In LCAT acivity of plasma, lipid supplemented groups were significantly(p<0.05) higher than non-lipid group, vegetable oil groups were significantly (p<0.001) higher than animal fat groups, and sardine oil group were significalylty (p<0.001) higher than beef tallow group. Also perilla oil group was significanlty (p<0.05) higher than corn oil group, and sardine oil group was significantly (p<0.05) higher than perilla oil group. Low lipid group, compared with medium or high lipid group, showed higher activity of LCAT in plasma. In cholesterol synthetic activity of liver tissues culture, sardine oil group($\omega$3 EPA and DHA) was significantly(p<0.001) higher than other lipid groups, non-lipid group was significantly(p<0.001) higher than the lipid supplemented groups, and amimal fat group were significantly(p<0.001) higher than vegetable oil groups, but the synthetic activity was not affected by dietary lipid levels.