• 전기화학회지
• /
• 제18권1호
• /
• pp.24-30
• /
• 2015

일반적으로 저농도의 염 용액에서 탈염성능이 우수한 축전식 탈염기술에 고농도의 염을 함유한 용액을 처리할 수 있는 가능성을 확인하기 위해 spacer와 spiral 형태의 두 가지 모양의 유로에따라 이온교환수지를 채움으로써 탈염효율을 비교분석하고 기술의 적용가능성을 평가하였다. Spacer와 spiral 형태로 이온교환수지를 채운 축전식 탈염 셀의 탈염효율은 각각 77.21 및 99.94%로, 이는 spiral 형태의 유로에 채워진 이온교환수지가 유입수와 고르게 접촉할 수 있는 유로의 모양을 구성하기 때문에 많은 이온들이 제거될 수 있었다고 판단된다. 또한 pH와 축적 전하량의 변화량에서 탈염성능을 감소시킬 수 있는 페러데이 반응이 현저하게 줄어들었다. 따라서 본 연구를 통해 에너지효율적인 축전식 탈염 기술을 이용하여 고농도의 염 용액의 탈염에 대한 가능성을 제시해주었고, 이온교환수지의 혼합비율의 최적화와 연속식 전기탈이온 기술의 재생공정의 도입에 대한 추가적인 연구를 통해 이상적인 탈염기술을 개발하는 데 큰 기반이 될 것으로 기대된다.

• 한국생물물리학회:학술대회논문집
• /
• 한국생물물리학회 1998년도 학술발표회
• /
• pp.33-33
• /
• 1998

Oxidation and reduction of amino acid residues in proteins affect their functional properties. Especially, redox modulation of ion channel activities has been reported in number of ion channel proteins. In this study, we investigated the effects of tertiary-butyl hydrogen peroxide (tBHP) on the large-conductance Ca$\^$2＋/ -activated K$\^$+/(Maxi-K) channel of rat brain using lipid bilayer reconstitution technique.(omitted)

• 대한수의학회지
• /
• 제32권4호
• /
• pp.543-553
• /
• 1992

Properties of unitary ATP-sensitive $K^+$ channels were studied using planar lipid bilayer technique. Vesicles were prepared from bullfrog (Rana catesbeiana) skeletal muscle. ATP-sensitive $K^+$ (K (ATP)) channels were identified by their unitary conductance and sensitivity to ATP. In the symmetrical solution containing 200mM KCI, 10mM Hepes, 1mM EGTA and pH 7.2, single K (ATP) channels showed a linear current-voltage relations with slight inward rectification. Slope conductance at reversal potential was $60.1{\pm}0.43$ pS(n=3)). Micromolar ATP reversibly inhibited the channel activity when applied to the cytoplasmic side. In the range of -50~＋50 mV, the channel activity was not voltage-dependent, but the channel gating within a burst was more frequent at negative voltage range. Varying the concentrations of external/internal KCl(mM) to 40/200, 200/200, 200/100 and 200/40 shifted reversal potentials to $-30.8{\pm}2.9$(n=3), $-1.1{\pm}2.7$(n=3), 10.5 and 30.6(mV), respecrivety. These reversal potentials were close to the expected values by the Nernst equation, indicating nearly ideal selectivity for $K^+$ over $Cl^-$. Under bi-ionic conditions of 200mM external test ions and 200mM internal $K^+$, the reversal potentials for each test ion/K pair were measured. The measured reversal potentials were used for the calculation of the releative permeability of alkali cations to $K^+$ ions using the Goldman-Hodgkin-Katz equation. The permeability sequence of 5 cations relative to $K^+$ was $K^+$(1), $Rb^+$(0.49), $Cs^+$(0.27), $Na^+$(0.027) and $Li^+$(0.021). This sequence was recognized as Eisenman's selectivity sequence IV. In addition, modelling the permeation of $K^+$ ion through ATP-sensitive $K^+$ channel revealed that a 3-barrier 2-site multiple occupancy model can reasonably predict the observed current-voltage relations.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
• /
• pp.1341-1342
• /
• 2006

Electrical characteristics of field-effect thin film transistors (TFTs) with p-channels of CdTe/CdHgTe core-shell nanocrystals are investigated in this paper. For the fabrication of bottom- and top-gate TFTs, CdTe/CrHgTe nanocrystals synthesized by colloidal method are first dispersed on oxidized p+ Si substrates by spin-coating, the dispersed nanoparticles are sintered at $150^{\circ}C$ to form the channels for the TFTs, and $Al_{2}O_{3}$ layers are deposited on the channels. A representative bottom-gate field-effect TFT with a bottom-gate $SiO_2$ layer exhibits a mobility of $0.21cm^2$/ Vs and an Ion/Ioff ratio of $1.5{\times}10^2$ and a representative top-gate field-effect TFT with a top-gate $Al_{2}O_{3}$ layer provides a field-effect mobility of $0.026cm^2$/ Vs and an Ion/Ioff ratio of $2.5{\times}10^2$. $Al_{2}O_{3}$ was deposited for passivation of CdTe/CdHgTe core-shell nanocrystal layer, resulting in enhanced hole mobility, Ior/Ioff ratio by 0.25, $3{\times}10^3$, respectively. The CdTe/CdHgTe nanocrystal-based TFTs with bottom- and top gate geometries are compared in this paper.

• 한국생물물리학회:학술대회논문집
• /
• 한국생물물리학회 2002년도 제9회 학술 발표회 프로그램과 논문초록
• /
• pp.34-34
• /
• 2002

Oxidative stress has been considered as a major cause of inducing cell damage, but it is recently recognized that mild oxidative stress or receptor-mediated production of ROS contributes to the regulation of various cellular functions. Several ion channels, such as L-type $Ca^{2＋}$ channels and $Ca^{2＋}$-activated $K^{＋}$ channels, have been shown to be regulated by oxidation of thiol group in their structure, and are suggested to be involved in ROS-sensitive cellular signaling.(omitted)

• The Korean Journal of Physiology and Pharmacology
• /
• 제21권1호
• /
• pp.75-82
• /
• 2017

The effects of acepromazine on human ether-$\grave{a}$-go-go-related gene (hERG) potassium channels were investigated using whole-cell voltage-clamp technique in human embryonic kidney (HEK293) cells transfected with hERG. The hERG currents were recorded with or without acepromazine, and the steady-state and peak tail currents were analyzed for the evaluating the drug effects. Acepromazine inhibited the hERG currents in a concentration-dependent manner with an $IC_{50}$ value of $1.5{\mu}M$ and Hill coefficient of 1.1. Acepromazine blocked hERG currents in a voltage-dependent manner between -40 and +10 mV. Before and after application of acepromazine, the half activation potentials of hERG currents changed to hyperpolarizing direction. Acepromazine blocked both the steady-state hERG currents by depolarizing pulse and the peak tail currents by repolarizing pulse; however, the extent of blocking by acepromazine in the repolarizing pulse was more profound than that in the depolarizing pulse, indicating that acepromazine has a high affinity for the open state of the channels, with a relatively lower affinity for the closed state of hERG channels. A fast application of acepromazine during the tail currents inhibited the open state of hERG channels in a concentration-dependent. The steady-state inactivation of hERG currents shifted to the hyperpolarized direction by acepromazine. These results suggest that acepromazine inhibits the hERG channels probably by an open- and inactivated-channel blocking mechanism. Regarding to the fact that the hERG channels are the potential target of drug-induced long QT syndrome, our results suggest that acepromazine can possibly induce a cardiac arrhythmia through the inhibition of hERG channels.

• The Korean Journal of Physiology and Pharmacology
• /
• 제24권4호
• /
• pp.287-298
• /
• 2020

Ca²⁺ signaling of endothelial cells plays a critical role in controlling blood flow and pressure in small arteries and arterioles. As the impairment of endothelial function is closely associated with cardiovascular diseases (e.g., atherosclerosis, stroke, and hypertension), endothelial Ca²⁺ signaling mechanisms have received substantial attention. Increases in endothelial intracellular Ca²⁺ concentrations promote the synthesis and release of endothelial-derived hyperpolarizing factors (EDHFs, e.g., nitric oxide, prostacyclin, or K⁺ efflux) or directly result in endothelial-dependent hyperpolarization (EDH). These physiological alterations modulate vascular contractility and cause marked vasodilation in resistance arteries. Transient receptor potential (TRP) channels are nonselective cation channels that are present in the endothelium, vascular smooth muscle cells, or perivascular/sensory nerves. TRP channels are activated by diverse stimuli and are considered key biological apparatuses for the Ca²⁺ influx-dependent regulation of vasomotor reactivity in resistance arteries. Ca²⁺-permeable TRP channels, which are primarily found at spatially restricted microdomains in endothelial cells (e.g., myoendothelial projections), have a large unitary or binary conductance and contribute to EDHFs or EDH-induced vasodilation in concert with the activation of intermediate/small conductance Ca²⁺-sensitive K⁺ channels. It is likely that endothelial TRP channel dysfunction is related to the dysregulation of endothelial Ca²⁺ signaling and in turn gives rise to vascular-related diseases such as hypertension. Thus, investigations on the role of Ca²⁺ dynamics via TRP channels in endothelial cells are required to further comprehend how vascular tone or perfusion pressure are regulated in normal and pathophysiological conditions.

• 멤브레인
• /
• 제28권6호
• /
• pp.388-394
• /
• 2018

탄소나노튜브(CNT) 기반의 멤브레인은 높은 물 전달률과 직경에 따른 이온 배제율로 해수담수, 물질 정화 등을 위한 분리막으로써의 가능성을 보여 주었다. 이온 선택성은 CNT 기반 멤브레인의 응용 분야를 확대하기 위한 중요한 요소이며, 기능기를 이용하여 이온 선택성의 조절이 가능함이 보고되었다. 다양한 원자가/크기의 이온이 혼합될 경우, 이온-기능기간 작용력 뿐만 아니라 이온-이온간의 작용력, 이온의 크기에 의한 반발력 등이 복합적으로 작용한다. 이에 본 연구에서는 분자동역학 전산모사를 통하여, 상이한 원자가/크기를 가진 이온의 혼합이 기능화된 CNT의 이온 선택성에 미치는 영향을 연구하였다. Potential of Mean Force 계산을 통하여 이온 투과에 대한 자유 에너지 장벽을 계산하였으며, CNT 크기 변화, 전하량 변화를 통하여 이온 선택성과 배제에 영향을 미치는 요소를 분석하였다. 본 연구는 CNT 멤브레인을 이용한 분리막 설계, 생체 이온 전달 채널 모사 등에 유용할 것으로 기대한다.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2009년 춘계학술대회논문집
• /
• pp.368-376
• /
• 2009

Studies on the effect of the wall-ion, wall-water, water-ion and ion-ion interaction on properties of water and ions in nano-channels have been performed through the use of different kinds of ions or different models of potential energy between wall-ion or wall-water. On this paper, we address the effect of water-wall interaction potential on the properties of confined aqueous solution by using the molecular dynamics (MD) simulations. As the interaction potential energies between water and wall we employed the models of the Weeks-Chandler-Andersen (WCA) and Lennard-Jones (LJ). On the MD simulations, 680 water molecules and 20 ions are included between uniformly charged plates that are separated by 2.6 nm. The water molecules are modeled by using the rigid SPC/E model (simple point charge/Extended) and the ions by the charged Lennard-Jones particle model. We compared the results obtained by using WCA potential with those by LJ potential. We also compared the results (e.g. ion density and electro-static potential distributions) in each of the above cases with those provided by solving the Poisson-Boltzmann equation.

• 고려인삼연구와산업
• /
• 제3권2호
• /
• pp.3-15
• /
• 2009