• BMB Reports
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• 제48권9호
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• pp.495-500
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• 2015

Up-regulation of cell adhesion molecules and proinflammatory cytokines contributes to enhanced monocyte adhesiveness and infiltration into the skin, during the pathogenesis of various inflammatory skin diseases, including atopic dermatitis. In this study, we examined the anti-inflammatory effects of butein, a tetrahydroxychalcone, and its action mechanisms using TNF-α-stimulated keratinocytes. Butein significantly inhibited TNF-α-induced ICAM-I expression and monocyte adhesion in human keratinocyte cell line HaCaT. Butein also decreased TNF-α-induced pro-inflammatory mediators, such as IL-6, IP-10 and MCP-1, in HaCaT cells. Butein decreased TNF-α-induced ROS generation in a dose-dependent manner in HaCaT cells. In addition, treatment of HaCaT cells with butein suppressed TNF-α-induced MAPK activation. Furthermore, butein suppressed TNF-α-induced NF-kappaB activation. Overall, our results indicate that butein has immunomodulatory activities by inhibiting expression of proinflammatory mediators in keratinocytes. Therefore, butein may be used as a therapeutic agent for the treatment of inflammatory skin diseases. [BMB Reports 2015; 48(9): 495-500]

• Journal of Korea Foundry Society
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• 제18권4호
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• pp.364-372
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• 1998

Effects of Si and Ca additions on the mechanical properties of AM60 based Mg alloys have been investigated. Hardness of the AM60 based Mg alloys reached a maximum value after aging for approximately 33 hours but the amount of hardness increase was negligible. The poor age hardening response of the alloys was due to low Al content, which implies that Al content must be >6 wt.% to observe age hardening effect. The tensile and yield strength increased with increasing Al, Si, and Ca content but elongation decreased with increasing Al and Si content. The best mechanical properties obtained in AM 40-2.5Si-0.2Ca alloy after T4 heat treatment were as follows; tensile strength 193.4 MPa, yield strength 79.2 MPa, and elongation 11.2%. High temperature property obtained from creep test was also improved by introducing $Mg_2Si$ which has high hardness, high melting temperature and low thermal expansion coefficient.

• The Korean Journal of Physiology and Pharmacology
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• 제4권6호
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• pp.463-469
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• 2000

It has been well known that 4-aminopyridine (4-AP) has an excitatory effect on vascular smooth muscle due to causing membrane depolarization by blocking $K^+-channel$. However, we observed that 4-AP had an inhibitory effect on the mesenteric artery of rat. Therefore, we investigated the mechanism of 4-AP-induced vasorelaxation. The mesenteric arcuate artery and its branches were isolated and cut into ring. The ring segment was immersed in HEPES-buffered solution and its isometric tension was measured. 4-AP $(0.1{\sim}10\;mM)$ induced a concentration-dependent relaxation, which was unaffected by NO synthase inhibitor, $N^G-nitro-L-arginine$ methylester $(100\;{\mu}M)$ or soluble guanylate cyclase inhibitor, methylene blue $(100\;{\mu}M).$ Glibenclamide $(100\;{\mu}M)$, ATP-sensitive $K^+$ channel blocker, did not exert any effect on the 4-AP-induced vasorelaxation. 4-AP relaxed the sustained contraction induced by 100 mM $K^+$ or $Ca^{2+}$ ionophore, A23187 $(100\;{\mu}M)$ in a dose-dependent manner. In addition, 4-AP significantly decreased the phasic contractile response to norepinephrine in the absence of extracellular $Ca^{2+}$. However, 4-AP did not block the $^{45}Ca$ influx of rat aorta. From the above results, we suggest that 4-AP may not block the $Ca^{2+}$ influx through $Ca^{2+}-channel,$ but act as a nonspecific vasorelaxant in arterial smooth muscle.

• Journal of Life Science
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• 제15권3호
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• pp.453-460
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• 2005

This investigation was performed to study Cd toxicity and the influence of Ca on Cd toxicity in growth, and photosynthetic pigments and enzymes in tobacco. Cd inhibited both growth and level of chlorophyll, but the inhibition was compensated by the treatment of Ca. Especially, chlorophyll content was significantly increased by the combination of Cd and Ca treatment compared with Cd treatment alone. In addition, activity and content of rubisco by Cd treatment was also significantly lesser than the non-treated control. The highly reduced activity of rubisco was minimized by the combined treatment of Ca to Cd. Rubisco activase activity and content also showed a pattern of change similar to the rubisco level, suggesting that Cd- and Ca-induced changes of rubisco could be caused by rubisco activase.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 초전도 자성체
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• pp.64-67
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• 2002

The Physical and magnetic properties such as microstructure, permeability and power loss of Ni-Zn ferrite with composition of $Ni_{0.8}Zn_{0.2}Fe_2O_4$, were investigated as the function of $Bi_2O_3$ and CaO contents. The power loss increased in proportion to the amount of $Bi_2O_3$ up to 0.3 wt% but it decreased over than 0.3 wt% addition. The highest permeability of 134 was obtained to the specimen added 1.0 wt% $Bi_2O_3$ since $Bi_2O_3$ contents were strongly dominant to grain growth and size than that of CaO. $Bi_2O_3$ liquid phase created during sintering process promoted sintering and grain growth so that grain size and permeability increased compared to that of the specimens which were sintered with free-additive and CaO. Also, lots of pores existed in the specimen which was added $Bi_2O_3$ wt% with the biggest grain size.

• Proceedings of the Korean Institute of Building Construction Conference
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.24-25
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• 2017

Gamma-C₂S (γ-C₂S) is a substance that is difficult to react with water under normal temperature but can absorb a large amount of CO₂ in the air. The addition of γ-C₂S to cementitious materials through the curing of CO₂ can improve the pore structure and improve the durability of the material. In this study, three kind of Ca-bearing materials : CaO, Ca(OH)₂, CaCO₃, were calcined 2.5h at 1450℃ to synthesize γ-C₂S after mixing with SiO₂ respectively. Among them, Ca(OH)₂ mixed with SiO₂ after calcining shows highest content. Synthesized γ-C₂S was added to the cement mortar, after water curing for 1 month, accelerated carbonation test was experimented. After 28d accelerated carbonation test, pore structure will be detectived by MIP. Based on the MIP result, following the calculation method of Fractal theory, the pore structure will be quantitative described.

• Korean Journal of Environmental Agriculture
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• 제22권4호
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• pp.290-293
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• 2003

To measure an effects of strontium on secretion of ${\alpha}$-amylase and RNase, wheat aleurone layers were isolated after the pre-incubation in a solution with or without 10 mM $SrCl_2$ or $CaCl_2$ for 3 days at $25^{\circ}C$ in the dark under aseptic conditions. The secretion of ${\alpha}$-amylase reached a maximum at 72 h after incubation. $Sr^{2+}$ induced more effectively secretion of ${\alpha}$-amylase than $Ca^{2+}$. The ${\alpha}$-amylase secretions by $Sr^{2+}$ or $Ca^{2+}$ ware about $2 (Ca^{2+})$ to $2.5 (Sr^{2+})$ fold higher than it without divalent ions, When aleurone layers were incubated without divalent ions, however, the ${\alpha}$-amylase was remarkably retained in the tissues. Total ${\alpha}$-amylase synthesis (ie. tissues + media) was slightly lowered by 10mM $SrCl_2$ addition. It seemed that the RNase secretion begins at 18 h after incubation. This meaned that the RNase secretion may process slower than ${\alpha}$-amylasee secretion. $Ca^{2+}$ effect on RNase secretion is stronger than $Sr^{2+}$ unlikely to ${\alpha}$-amylase. The secretion process is likely to be suddenly induced between 72 hand 96 h. These results suggested that the secretion was enhanced after the accumulation in aleurone layers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.323-323
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• 2007

Influence of $La_2O_3$ addition to $CaO-B_2O_3$-based glass on the water leaching resistance of the glass was first investigated. The optimized $La_2O_3-CaO-B_2O_3$(LCB) glass was ball milled for varying time, followed by mixing with $Al_2O_3$ crystalline phase to form $Al_2O_3$-LCB glass composites at $875^{\circ}C$ for 1h. Microwave dielectric properties of the composites were investigated as a function of the ball milling time of the LCB glass. Dielectric constant and quality factor of the composites were 6.31 and 13856 GHz, respectively, when the LCB glass was ball milled for 2h prior to mixing with $Al_2O_3$.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• 제45권6호
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• pp.44-54
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• 2013

Replacing OMG (old magazine) to ONP (old newspaper) by raising optical property through $CaCO_3$ in-situ precipitation method in white duplex board presents cost reduction and possible drying energy saving. The strength property impairment by the presence of $CaCO_3$ could be supplemented by the fiber furnish treatment or strength polymer addition. In $CaCO_3$ in-situ precipitation of ONP, it was found from morphological study using FlowCAM, an image analyzer, that most of calcium carbonate were formed on the fines, and made the size of the fines larger. For the case of forming calcium carbonate only on the fractionated fines, the size of the fines were the biggest, and there were more clean surface areas available for bonding for the fractionated long fibers when fractionated fibers and fines were regrouped to make paper.

• Biomedical Science Letters
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• 제25권2호
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• pp.123-130
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• 2019

Platelet aggregation is essential for hemostatic process in case of blood vessels damages. However, excessive platelet aggregation can cause cardiovascular disorders including atherosclerosis, thrombosis and myocardial infarction. Scopoletin is usually found in the roots of genus Scopolia or Artemisia, and is known to have anticoagulant and anti-malarial effects. This study investigated the effect of scopoletin on human platelet aggregation induced by U46619, an analogue of thromboxane $A_2(TXA_2)$. Scopoletin had anti-platelet effects by down-regulating $TXA_2$ and intracellular $Ca^{2+}$ mobilization ($[Ca^{2+}]_i$), the aggregation-inducing molecules generated in activated platelets. On the other hand, scopoletin increased the levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are known to be intracellular $Ca^{2+}$ antagonists. This resulted in inhibition of fibrinogen binding to ${\alpha}IIb/{\beta}_3$ in U46619-induced human platelet aggregation. In addition, scopoletin inhibited the release of adenosine trisphosphate (ATP) in dose-dependent manner. This result means that the aggregation amplification activity through the granule secretion in platelets was suppressed by scopoletin. Therefore, we demonstrated that scopoletin has a potent antiplatelet effect and is highly likely to prevent platelet-derived vascular disease.