• Membrane Journal
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• v.30 no.1
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• pp.38-45
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• 2020

Although Lithium metal battery (LMB) has a very large theoretical capacity, it has a critical problem such as formation of dendrite which causes short circuit and short cycle life of the LMB. In this study, PDMS/GO composite with evenly dispersed graphene oxide (GO) nanosheets in poly (dimethylsiloxane) (PDMS) was synthesized and coated into a thin film, resulting in the effect that can physically suppress the formation of dendrite. However, PDMS has low ion conductivity, so that we attained improved ion conductivity of PDMS/GO thin film by etching technic using 5wt% hydrofluoric acid (HF), to facilitate the movement of lithium (Li) ions by forming the channel of Li ions. The morphology of the PDMS/GO thin film was observed to confirm using SEM. When the PDMS/GO thin film was utilized to lithium metal battery system, the columbic efficiency was maintained at 87.4% on average until the 100^th cycles. In addition, voltage profiles indicated reduced overpotential in comparison to the electrode without thin film.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.387-390
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• 2006

매립장주변의 대수층 특성과 수리지화학적 특성과의 상관관계 분석은 매립장 환경 위해 요인을 평가하는데 중요한 역할을 하며 이를 위해 생활쓰레기 매립장인 금산 매립장을 대상으로 연구를 수행하였다. 대수층 매질 특성을 파악하기 위해 토양시료를 채취하여 중금속 성분 및 pH, 전기전도도, 용존유기탄소, 양이온교환능력, 유기물함량, 토양 입도분석을 수행하였고, 수리지화학적 특성 파악을 위해 수질검층 및 지하수 시료를 분석하여 매립지역의 수직 및 수평적인 분포 특성을 파악하였다. 대수층의 토양특성과 지하수 수질특성의 비교분석 결과 침출수 집수정을 기점으로 침출수의 영향을 받은 관측정의 전기전도도(EC) 측정값이 배경 지하수에 비해 상대적으로 높은 값을 보여 주었다. 입도분석 결과 상부 표토에 가까운 50cm 이내의 토양은 농경의 영향으로 심부보다 상대적으로 실트질 토양이 많고 이보다. 심부의 토양은 사질 토양으로 되어 있었다. 이러한 투수성이 좋은 사질 토양은 지하수의 이동을 비교적 쉽게 유도하기 때문에 매립장으로부터 침출수가 누출되었을 때 지하수 흐름을 따라 빠르게 이동할 수 있는 통로로 작용될 것으로 판단된다.

• The Korean Journal of Pharmacology
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• v.17 no.1 s.28
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• pp.9-15
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• 1981

Aconiti tuber butanol fraction, which is isolated from the chloroform insoluble and water soluble extract of Aconitum volubile, has been recently known to have a potent positive inotropic effect in the isolated cardiac muscle preparations of various animals. The positive inotropic mechanism of Aconiti tuber butanol fraction, in relation with the external calcium, was studied using the isolated cat papillary muscle. The positive inotropic effect was dependent on the calcium concentration in the nutrient medium, and a synergistic relation could be demonstrated between Aconiti tuber butanol fraction and the external calcium. The inotropic effect of $10^{-4}g/ml$ of Aconiti tuber butanol fraction was equivalent to that of 0.06mM of calcium in the medium. After the treatment with a calcium influx inhibitor, Verapamil$(2{\pm}10^{-7}-10^{-6}M)$, the contractile force of the papillary muscle was markedly inhibited. In these preparations, Aconiti tuber butanol fraction restored the decreased contractility in a dose-dependent manner. It was suggested that the positive inotropic effect of Aconiti tuber butanol fraction might be related with the stimulating action on the calcium influx through the slow inward calcium channels in the cardiac cell membrane. In contrast with digitalis cardiac glycoside, Aconiti tuber butanol fraction infused intravenously into the anesthetized rabbit decreased the systemic arterial blood pressure and increased the carotid blood flow, but produced no prominent changes in the heart rate.

• Journal of the Korean Chemical Society
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• v.32 no.1
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• pp.9-14
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• 1988

Perovskite type compounds of the $La_{1-x}Ca_xFeO_{3-y}$ system were prepared from stoichiometric mixtures of La_2O_3,\;CaCO_3$, and Fe(NO-3)_3{\cdot}9H_2O$ by heating at 1100$^{\circ}C$ for 24 hours. The crystallographic structures of the solid solutions of all compositions were orthorhombic systems. X-ray diffraction and Mohr salt analysis revealed that at higher y value the phase transition due to vacancy ordering occured and that the lattice volume decreased when the x value was increased. The value of nonstoichiometric ratio y were found to be in the range of $0.0{\sim}0.5$. Electrical conductivities of this systems are measured in temperature range of -100 to 100$^{\circ}C$. Ionic contribution to total conductivity was found from activation energy in the phase containing the open pathway due to vacancy ordering.

• Journal of Ginseng Research
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• v.29 no.4
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• pp.167-175
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• 2005

The $Ca^{2+}-activated$ chloride channel (CLCA) was activated by ginseng total saponin (GTS) in Xenopus oocytes. The reverse transcription PCR (RT-PCR) method was performed with gene specific primers on oocytes. The gene specific primers were deduced from spleen cDNA in expressed sequence tags (EST) database showing high homology to the mouse CLCA. Full length of cDNA sequence was completed by linkage of several 5' and 3'-half cDNA fragments have been sequenced. We named the full cDNA to oCLCA transiently. The oCLCA gene encodes a protein of 911 amino acids with $48.9\%$ identity overall to that of mouse CLCA (mCLCA4). A predicted oCLCA amino acids sequence shows the molecular weight of 108 kDa and has four or more transmembrane domains, and also the one hydrophobic C­terminal domain. oCLCA gene was expressed ubiquitously in various tissues included oocytes, also interfered in oocytes by siRNA for oCLCA. Here, we suggest that oCLCA is a endogenous chloride channel gene in oocytes. We are studying for the identification of oCLCA gene and further physiological research.

• Journal of Korean Medicine for Obesity Research
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• v.18 no.1
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• pp.10-18
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• 2018

Objectives: Metabolic syndrome is correlated with increased cardiovascular risk and characterized by several factors, including visceral obesity, hypertension, insulin resistance, and dyslipidemia. Several members of a large family of nonselective cation entry channels, e.g., transient receptor potential (TRP) melastatin 7 (TRPM7) channels have been associated with the development of cardiovascular diseases. The purpose of this study was to investigate the effects of Dangkwisoo-san, ginger and curcumin on TRPM7 channel. Methods: Human embryonic kidney (HEK) 293 cells stably transfected with the TRPM7 expression vectors were maintained in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetal bovine serum (FBS), 1% penicillin/streptomycin, $5{\mu}g/mL$ blasticidin, and 0.4 mg/mL zeocin in a humidified 20% $O_2$/10% $CO_2$ atmosphere at $37^{\circ}C$. Whole-cell patch clamp recordings were obtained using an Axopatch 700B amplifier and pClamp v.10.4 software, and signals were digitalized at 5 kHz using Digidata 1422A. Results: Dangkwisoo-san extract (100, 200, 300, 400, and $500{\mu}g/mL$) inhibited the outward and inward TRPM7 whole-cell currents at dose dependent manner and the half maximal inhibitory concentration $(IC)_{50}$ of Dangkwisoo-san was $218.3{\mu}g/mL$. Also, ginger extract (100, 200, 300, 400, and $500{\mu}g/mL$) inhibited the outward and inward of TRPM7 whole-cell currents in a dose dependent manner and the $IC_{50}$ of ginger was $877.2{\mu}g/mL$. However, curcumin had no effects on TRPM7 whole-cell currents. Conclusions: These results suggest that both Dangkwisoo-san and ginger have good roles to inhibit the TRPM7 channel, suggesting that Dangkwisoo-san and ginger are considered one of the candidate agents for the treatment of metabolic syndrome such as cardiovascular disease.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.2
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• pp.54-62
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• 2024

SICM (Scanning Ion Conductivity Microscopy) is a technique for measuring surface topography in an environment where electrochemical reactions occur, by detecting changes in ion conductivity as a nanopipette tip approaches the sample. This study includes an investigation of the current response curve, known as the approach curve, according to the distance between the tip and the sample. First, a simulation analysis was conducted on the approach curves. Based on the simulation results, then, several measuring experiments were conducted concurrently to analyze the difference between the simulated and measured approach curves. The simulation analysis confirms that the current squeezing effect occurs as the distance between the tip and the sample approaches half the inner radius of the tip. However, through the calculations, the decrease in current density due to the simple reduction in ion channels was found to be much smaller compared to the current squeezing effect measured through actual experiments. This suggests that ion conductivity in nano-scale narrow channels does not simply follow the Nernst-Einstein relationship based on the diffusion coefficients, but also takes into account the fluidic hydrodynamic resistance at the interface created by the tip and the sample. It is expected that SICM can be combined with SECM (Scanning Electrochemical Microscopy) to overcome the limitations of SECM through consecutive measurement of the two techniques, thereby to strengthen the analysis of electrochemical surface reactivity. This could potentially provide groundbreaking help in understanding the local catalytic reactions in electroless plating and the behaviors of organic additives in electroplating for various kinds of patterns used in semiconductor damascene processes and packaging processes.

• The Korean Journal of Pharmacology
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• v.24 no.2
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• pp.179-187
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• 1988

Verapamil, tetrodotoxin and tetraethylammonium chloride in the stated amount did not affect the $Na^{++}$ induced $Ca^{++}$ release. $Cd^{++}$ and $Zn^{++}$ significantly inhibited the $Na^{++}$ induced $Ca^{++}$ release. $Mn^{++}$ also inhibited $Na^+-Ca^{++}$ exchange. $Cd^{++}$ inhibited $Na^+-Ca^{++}$ exchange noncompetitively with an apparent inhibition constant (Ki) of $100\;{\mu}M$. $Cd^{++}$ caused loss of sulfhydryl group, whereas $Zn^{++}$ did not show any significant effect. $Cd^{++}$ and $Zn^{++}$ effectively inhibited $Na^+-Ca^{++}$ ATPase and slightly inhibited $Ca^{++}-Mg^{++}$ ATPase. Carbonyl cyanide chlorophenylhydrazone, 2,4-dinitrophenol and sodium arsenate stimulated the $Na^{++}$ induced $Ca^{++}$ release. Dibucaine and oligomycin slightly inhibited it. The results suggest that the $Na^+-Ca^{++}$ exchange on the synaptosomal plasma membrane may be not accomplished by ion channels. The $Na^+-Ca^{++}$ exchange is sensitively inhibited by $Cd^{++}$ and this transport process appears to be partially regulated by sulfhydryl groups of the synaptosomal plasma membrane. It is also postulated that $Na^+-Ca^{++}$ exchange is suppressed during the phosphorylation reaction of protein component on the neuronal membrane.

• Journal of Ginseng Research
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• v.26 no.1
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• pp.1-5
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• 2002

It has been well known that Korea red ginseng has an antihypertensive effect. The antihypertensive effect may be due to its ability to change the peripheral resistance. Change of vascular tone in the resistance-sized artery contribute to the peripheral resistance, thereby regulate the blood pressure. Therefore, we investigated to clarify the vasorelaxing mechanism induced by crude saponin of Korea red ginseng in the resistance-sized mesenteric artery of rats. The resistance-sized mesenteric artery was isolated and cut into a ring. The ring segment was immersed in HEPES-buffered solution and its isometric tension was measured using myograph force-displacement transducer. Crude saponin of ginseng relaxed the mesenmetric arterial rings precontracted with norepinephrine (3$\mu$M) in dose-dependent manner (0.01 mg/㎖ -1 mg/㎖. The relaxation by crude saponin was smaller in endothelium-intact preparation than that in endothelium-denuded preparation. The contraction induced by A23187 or phorbol 12,13-dibutyrate was not affected by crude saponin of ginseng. The vasorelaxing effect of crude saponin of ginseng was significantly attenuated by the increase of the extracellular K$\^$+/ concentration. Crude saponin-induced vasorelaxation was not affected by tetraethylammonium (1 mM), glybenclamide (10$\mu$M), and 4-aminopyridine (0.1 mM) in these preparations. Ba$\^$2+/(10$\mu$M ∼100$\mu$M) markedly reduced the crude saponin-induced vasorelakation dose-dependently. From the above results, we suggest that crude saponin of ginseng may stimulate K$\^$+/ efflux and hyperpolarize the membrane, thereby cause the vasorelaxation in the resistance-sized mesenteric artery of rats.

• Journal of Life Science
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• v.32 no.2
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• pp.175-188
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• 2022

Relaxin has been demonstrated to have regulatory functions on both the smooth muscle and extracellular matrix (ECM) of blood vessels and fibrotic organs. The diverse mechanisms by which relaxin acts on small resistance arteries and fibrotic organs, including the bladder, are reviewed here. Relaxin induces vasodilation by inhibiting the contractility of vascular smooth muscles and by increasing the passive compliance of vessel walls through the reduction of ECM components, such as collagen. The primary cellular mechanism whereby relaxin induces arterial vasodilation is mediated by the endothelium-dependent production of nitric oxide (NO) through the activation of RXFP1/PI3K, Akt phosphorylation, and eNOS. In addition, relaxin triggers different alternative pathways to enhance the vasodilation of renal and mesenteric arteries. In small renal arteries, relaxin stimulates the activation of the endothelial MMPs and EtB receptors and the production of VEGF and PlGF to inhibit myogenic contractility and collagen deposition, thereby bringing about vasodilation. Conversely, in small mesenteric arteries, relaxin augments bradykinin (BK)-evoked relaxation in a time-dependent manner. Whereas the rapid enhancement of the BK-mediated relaxation is dependent on IK_Ca channels and subsequent EDH induction, the sustained relaxation due to BK depends on COX activation and PGI₂. The anti-fibrotic effects of relaxin are mediated by inhibiting the invasion of inflammatory immune cells, the endothelial-to-mesenchymal transition (EndMT), and the differentiation and activation of myofibroblasts. Relaxin also activates the NOS/NO/cGMP/PKG-1 pathways in myofibroblasts to suppress the TGF-β1-induced activation of ERK1/2 and Smad2/3 signaling and deposition of ECM collagen.