• Journal of the Korean Ceramic Society
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• v.20 no.1
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• pp.37-42
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• 1983

An attempt was made to derive a possible synthetic mechanism of Fluoro-phlogopite (Mica, 4Mg.$Al_2O_3$.$6SiO_2$.$K_2O$.$2MgF_2$) The pevention of fluorine vaporization turned out to be the key in the synthesis of Mica in question.l Consequently the quinary system of Mica was seperately synthesized ; frist 4MgO.$Al_2O_3-6SiO_2$(ternary system) was sintered at 135$0^{\circ}C$ and $K_2O$ and $MgF_2$ were added and second 4MgO.$Al_2O_3-6SiO_2$.$K_2O$ (quarternary system) was heat-treated at 135$0^{\circ}C$ and $MgF_2$ was added. The ternary system resulted in Proto-enstatite Cordierite and Spinel phases while Forsterite and Leucite were shown in the quarternay system . In both methods Fluoro-phlogopite was systhesized but the solid state reactions to form Mica from the ternary system and the quarternary system were different. High temperature reactions in the formation of Mica were investigated employing XRD, DTA and SEM The study of the synthesis of Mica indirectly suggested a method of phase analysis of quinary system(MgO-$Al_2O_3-SiO_2-K_2O-MgF_2$) and quarternary system(MgO-$Al_2O_3-SiO_2-K_2O-MgF_2$) at various temperatures.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.367-375
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• 2017

In this study, NO oxidation process was studied to increase the NO treatment efficiency of pollutant present in exhaust gas. $H_2O_2$ catalytic cracking was introduced as a method of producing dry oxidizing agents with strong oxidizing power. The $K-Mn/Fe_2O_3$ heterogeneous catalysts applicable to the $H_2O_2$ decomposition process were prepared and their physico-chemical properties were investigated. The prepared dry oxidant was applied to the NO oxidation process to treat the simulated exhaust gas containing NO, NO conversion rates close to 100% were confirmed at various flow rates (5, 10, 20 L/min) of the simulated flue gas.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.2
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• pp.455-459
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• 2006

The inhibitors of prostaglandin $E_2\;(PGE_2)$ production and cyclooxygenase-2 (COX-2) activity have been considered as potential anti-inflammatory agents. In this study, we evaluated 9 compounds isolated from 5 Korean phytomedicinal plants (Spirea prunifolia, Paeonia suffruticosa, Salvia miltiorrhiza, Scutellaria baicalensis, and Artemisia capillaris) for the inhibition of $PGE_2$production and COX-2 expession in lipopolysaccharide (LPS)-stimulated human macrophages U937 cells. As a result, several compound such as prunioside A, penta-O-galloyl-beta-D-glucose, tanshinone IIA, baicalin, baicalein, wogonin, scopolatin, scoparone and decursinol showed potent inhibition of $PGE_2$production (50-70% inhibition at the test concentration of $10\;{\mu}M$). In addition, these compounds were also considered as potential inhibitors of COX-2 activity (45-73% inhibition at the test concentration of $10\;{\mu}M$). These active compound mediating COX-2 inhibitory activities are warranted for further elucidation of active principles for development of anti-inflammatory agents and these properties may contribute to the anti-atopic dermatitis activity.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1863-1868
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• 2004

Kringle 5 (K5), located outside of angiostain (K1-4) in human plasminogen, displays more potent antiangiogenic activity on endothelial cell proliferation than angiostatin itself. Using a yeast two-hybrid system in vivo, we have recently identified Rgl2 (guanine nucleotide dissociation stimulator (RalGDS)-like factor 2) as a binding protein of human K5. In order to confirm in vitro protein interaction between K5 and Rgl2, we developed bacterial recombinant expression systems for them. K5 and Rgl2 proteins were expressed in high yields and purified into pure forms with His tags and GST fusion, respectively. GST-pull down experiments clearly demonstrated that K5 interacts specifically with Rgl2 in vitro. These results indicate that Rgl2 functions as a receptor protein for K5 in vitro as well as in vivo, leading to anti-angiogenesis through regulating Ras signaling pathways.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.5
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• pp.731-738
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• 2016

Glucagon-like peptide-2 (GLP-2) is important for intestinal barrier function and regulation of tight junction (TJ) proteins, but the intracellular mechanisms of action remain undefined. The purpose of this research was to determine the protective effect of GLP-2 mediated TJ and transepithelial electrical resistance (TER) in lipopolysaccharide (LPS) stressed IPEC-J2 cells and to test the hypothesis that GLP-2 regulate TJ and TER through the phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt)-mammalian target of rapamycin (mTOR) signaling pathway in IPEC-J2 cells. Wortmannin and LY294002 are specific inhibitors of PI3K. The results showed that $100{\mu}g/mL$ LPS stress decreased TER and TJ proteins occludin, claudin-1 and zonula occludens protein 1 (ZO-1) mRNA, proteins expressions (p<0.01) respectively. GLP-2 (100 nmol/L) promote TER and TJ proteins occludin, claudin-1, and zo-1 mRNA, proteins expressions in LPS stressed and normal IPEC-J2 cells (p<0.01) respectively. In normal cells, both wortmannin and LY294002, PI3K inhibitors, prevented the mRNA and protein expressions of Akt and mTOR increase induced by GLP-2 (p<0.01) following with the significant decreasing of occludin, claudin-1, ZO-1 mRNA and proteins expressions and TER (p<0.01). In conclusion, these results indicated that GLP-2 can promote TJ's expression and TER in LPS stressed and normal IPEC-J2 cells and GLP-2 could regulate TJ and TER through the PI3K/Akt/mTOR pathway.

• Journal of Energy Engineering
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• v.8 no.2
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• pp.279-284
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• 1999

Thermal analyses were conducted in a thermogravimetric analyzer by isothermal technique in order to characterize the Korean anthracites-nitrogen oxides reaction. The tested coal sample was Dogae anthracites and compared with SP-1 graphite. Carbon-NO and carbon-N$_2$O reactions were carried out with respect to isothermal reaction temperatures (550$^{\circ}C$-900$^{\circ}C$) and reactant gas partial pressures (5 kPa∼20 kPa). In NO reaction, measured reaction orders of NO concentration and activation energy were 0.45∼0.96 and 39∼l12 kJ/mol, respectively. In N$_2$O reaction, measured reaction orders of N$_2$O concentration and activation energy were 0.62∼0.87 and 190∼215.3 kJ/mol, respectively. Compared the Korean anthracites-nitrogen oxides reaction with the combustion reaction, the reaction rate in the oxidation below 700$^{\circ}C$ decreases in the order O$_2$>NO>N$_2$O. But above 700$^{\circ}C$, the reaction rate of N$_2$O is faster than that of NO.

• Archives of Pharmacal Research
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• v.29 no.2
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• pp.172-177
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• 2006

Hepatotoxic potential of 2, 3-dibromopropene (2, 3-DBPE) and its conjugation with glutathione (GSH) were investigated in male ICR mice. Treatment of mice with 20, 50, and 100 mg/kg of 2, 3-DBPE for 24 h caused elevation of serum alanine aminotransferase and aspartate aminotransferase activities. The hepatic content of GSH was not changed by 2, 3-DBPE. Meanwhile, the GSH content was slightly reduced when mice were treated with 2, 3-DBPE for 6 h and significantly increased 12 h after the treatment. Subsequently, a possible formation of GSH conjugate of 2, 3-DBPE was investigated in vivo. After the animals were treated orally with 20, 50, and 100 mg/kg of 2, 3-DBPE, the animals were subjected to necropsy 6, 12, and 24 h later. A conjugate of S-2-bromopropenyl GSH was identified in liver and serum treated with 100 mg/kg of 2, 3-DBPE by using liquid chromatography-electrospray ionization tandem mass spectrometry. The protonated molecular ions $[M+H]^+$ of S-2-bromopropenyl GSH were observed at m/z 425.9 and 428.1 in the positive ESI spectrum with a retention time of 6.35 and 6.39 min, respectively. In a time-course study in livers following an oral treatment of mice with 100 mg/kg of 2, 3-DBPE for 6, 12, and 24 h, the 2, 3-DBPE GSH conjugate was detected maximally 6 h after the treatment. The present results suggested that 2, 3-DBPE-induced hepatotoxicity might be related with the production of its GSH conjugate.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.3
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• pp.361-368
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• 1998

The spontaneous contractions of gastric smooth muscles are regulated by slow waves, which are modulated by both nervous system and humoral agents. This study was designed to examine the effects of prostaglandin $E_2$ ($PGE_2$) on the contractile and electrical activities of antral smooth muscles in guinea-pig stomach, using an intracellular recording technique. To elucidate the underlying mechanism for its effect on contractility, ionic currents were also measured using a whole-cell patch clamp method. The basal tone by $PGE_2$ was variable, whereas the magnitude of phasic contractions was reduced ($19.0{\pm}2.1%$, n=19). The resting membrane potentials were hyperpolarized ($-4.4{\pm}0.5%$ mV, n=10), and plateau potentials were lowered ($-2.9{\pm}0.5%$ mV, n=10). In most cases, however, the initial peak potentials of slow waves were depolarized more by $PGE_2$ than those of control. The frequency of the slows wave was increased from $5.7{\pm}0.2$ cycles/min to $6.5{\pm}0.2$ (n=22). Voltage-operated $Ca^{2+}$ currents were decreased by $PGE_2$ (n=5). Voltage-operated $K^+$ currents, both Ca-dependent and Ca-independent, were increased (n=5). These results suggest that $PGE_2$ plays an important role in the modulation of gastric smooth muscle activities, and its inhibitory effects on the contractility and activities of slow waves are resulted from both decrease of $Ca^{2+}$ currents and increase of $K^+$ currents.

• Bulletin of the Korean Chemical Society
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• v.27 no.10
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• pp.1708-1711
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• 2006

• The Pure and Applied Mathematics
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• v.26 no.1
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• pp.49-58
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• 2019

In this paper, I prove the stability problem for a quadratic-cubic functional equation $$f(x+ky)-k^2f(x+y)-k^2f(x-y)+f(x-ky)+f(kx)-{\frac{k^3-3k^2+4}{2}}f(x)+{\frac{k^3-k^2}{2}}f(-x)=0$$ in modular spaces by applying the direct method.