• Animal cells and systems
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• v.2 no.4
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• pp.471-476
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• 1998

The G protein-activated inwardly rectifying $K^＋$ channel (GIRK1) was coex-pressed in Xenopus oocytes along with the $5-HT_{1A}$ receptor, a 7-helix receptor known to be coupled to $K^＋$ channels in many neural tissues. Thus, the activation of the $5-HT_{1A}$ receptor by its agonist leads to the opening of GIRK1. The GIRK1 current was measured using the two electrode voltage clamp technique with bath application of 5-HT in the presence of various external potassium concentrations $[K^＋]_0$. GIRK1 showed a strong inward rectification since only hyperpolarizing voltages evoked inward currents. $K^{+}$ was the major ion carrier as evidenced by about 44㎷ voltage shift corresponding to a 10-fold external 〔$K^＋$〕 change. 5-HT induced a concentration-dependent inward $K^＋$ current ($EC_{50}{\equation omitted}10.7nM$) which was blocked by $Ba^{2＋}$. Pertussis toxin (PTX) pre-treatment reduced the $K^＋$ current by as much as about 70%, suggesting that PTX-sensitive G protein ($G_i or G_o$ type) are involved in the $5-HT_{1A}$ receptor-GIRK1 coupling in Xenopus oocytes.

• Journal of the Korean Applied Science and Technology
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• v.16 no.1
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• pp.33-40
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• 1999

We used Cu as a representative of metals to be directly adsorbed on the bare Si surface and studied its removal DHF, DHF-$H_2O_2$ and BHF solution. It has been found that Cu ion in DHF adheres on every Si wafer surface that we used in our study (n, p, n+, p+) especially on the n+-Si surface. The DHF-$H_2O_2$ solution is found to be effective in removing metals featuring high electronegativity such as Cu from the p-Si and n-Si wafers. Even when the DHF-$H_2O_2$ solution has Cu ions at the concentration of 1ppm, the solution is found effective in cleaning the wafer. In the case the n+-Si and p+-Si wafers, however, their surfaces get contaminated with Cu When Cu ion of 10ppb remains in the DHF-$H_2O_2$ solution. When BHF is used, Cu in BHF is more likely to contaminate the n+-Si wafer. It is also revealed that the surfactant added to BHF improve wettability onto p-Si, n-Si and p+-Si wafer surface. This effect of the surfactant, however, is not observed on the n+-Si wafer and is increased when it is immersed in the DHF-$H_2O_2$ solution for 10min. The rate of the metallic contamination on the n+-Si wafer is found to be much higher than on the other Si wafers. In order to suppress the metallic contamination on every type of Si surface below 1010atoms/cm2, the metallic concentration in ultra pure water and high-purity DHF which is employed at the final stage of the cleaning process must be lowered below the part per trillion level. The DHF-$H_2O_2$ solution, however, degrades surface roughness on the substrate with the n+ and p+ surfaces. In order to remove metallic impurities on these surfaces, there is no choice at present but to use the $NH_4OH-H_2O_2-H_2O$ and $HCl-H_2O_2-H_2O$ cleaning.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.6
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• pp.545-553
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• 2020

Aripiprazole is a quinolinone derivative approved as an atypical antipsychotic drug for the treatment of schizophrenia and bipolar disorder. It acts as with partial agonist activities at the dopamine D2 receptors. Although it is known to be relatively safe for patients with cardiac ailments, less is known about the effect of aripiprazole on voltage-gated ion channels such as transient A-type K⁺ channels, which are important for the repolarization of cardiac and neuronal action potentials. Here, we investigated the effects of aripiprazole on Kv1.4 currents expressed in HEK293 cells using a whole-cell patch-clamp technique. Aripiprazole blocked Kv1.4 channels in a concentration-dependent manner with an IC₅₀ value of 4.4 μM and a Hill coefficient of 2.5. Aripiprazole also accelerated the activation (time-to-peak) and inactivation kinetics. Aripiprazole induced a voltage-dependent (δ = 0.17) inhibition, which was use-dependent with successive pulses on Kv1.4 currents without altering the time course of recovery from inactivation. Dehydroaripiprazole, an active metabolite of aripiprazole, inhibited Kv1.4 with an IC₅₀ value of 6.3 μM (p < 0.05 compared with aripiprazole) with a Hill coefficient of 2.0. Furthermore, aripiprazole inhibited Kv4.3 currents to a similar extent in a concentration-dependent manner with an IC₅₀ value of 4.9 μM and a Hill coefficient of 2.3. Thus, our results indicate that aripiprazole blocked Kv1.4 by preferentially binding to the open state of the channels.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.194-194
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• 2017

Camelina (Camelina sativa L.) is a potential bio-energy crop that has short life cycle about 90 days and contains high amount of unsaturated fatty acid which is adequate to bio-diesel production. Enhancing environmental stress tolerance is a main issue to increase not only crop productivity but also big mass production. CsRCI2s (Rare Cold Inducible 2) are cold and salt stress related protein that localized at plasma membrane (PM) and assume to be membrane potential regulation factor. These proteins can be divide into C-terminal tail (CsRCI2D/E/F/G) or no-tail group (CsRCI2A/B/C/H). However, function of CsRCI2s are less understood. In this study, physiological responses and functional characterization of CsRCI2s of Camelina under salt stress were analyzed. Full-length CsRCI2s (A/B/E/F) and CsPIP2;1 sequences were confirmed from Camelina genome browser. Physiological investigations were carried out using one- or four-week-old Camelina under NaCl stress with dose and time dependent manner. Transcriptional changes of CsRCI2A/B/E/F and CsPIP2;1 were determined using qRT-PCR in one-week-old Camelina seedlings treated with NaCl. Translational changes of CsRCI2E and CsPIP2;1 were confirmed with western-blot using the antibodies. Water transport activity and membrane potential measurement were observed by cRNA injected Xenopus laevis oocyte. As results, root growth rate and physiological parameters such as stomatal conductance, chlorophyll fluorescence, and electrolyte leakage showed significant inhibition in 100 and 150 mM NaCl. Transcriptional level of CsPIP2;1 did not changed but CsRCI2s were significantly increased by NaCl concentration, however, no-tail type CsRCI2A and CsRCI2B increased earlier than tail type CsRCI2E and CsRCI2F. Translational changes of CsPIP2;1 was constitutively maintained under NaCl stress. But, accumulation of CsRCI2E significantly increased by NaCl stress. CsPIP2;1 and CsRCI2A/B/E/F co-expressed Xenopus laevis oocyte showed decreased water transport activity as 61.84, 60.30, 62.91 and 76.51 % at CsRCI2A, CsRCI2B, CsRCI2E and CsRCI2F co-expression when compare with single expression of CsPIP2;1, respectively. Moreover, oocyte membrane potential was significantly hyperpolarized by co-expression of CsRCI2s. However, higher hyperpolarized level was observed in tail-type CsRCI2E and CsRCI2F than others, especially, CsRCI2E showed highest level. It means transport of $Na^+$ ion into cell is negatively regulated by expression of CsRCI2s, and, function of C-terminal tail is might be related with $Na^+$ ion influx. In conclusion, accumulation of NaCl-induced CsRCI2 proteins are related with $Na^+$ ion exclusion and prevent water loss by CsPIP2;1 under NaCl stress.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.758-761
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• 2001

In this study, the nar promoter of E. coli was characterized to see whether the nar promoter cloned onto pBBR122 can be used as an expression promoter of gram negative microbes. For this purpose, a plasmid with lacZ gene expressing ${\beta}-galactosidase$ instead of the structural genes of nar operon in a gram negative host strain(Agrobacterium.tumefaciens) was used to simplify an assay of induction of the nar promoter. The following effects were investigated to find optimal conditions: methods of inducing the nar promoter, optimal nitrate concentration, maximally inducing the nar promoter, the amount of expressed ${\beta}-galactosidase$ and induction ratio(specific ${\beta}-galactosidase$ activity after maximal induction/specific ${\beta}-galactosidase$ activity before induction). The following results were obtained from the experiments: the growth of Agrobacterium with E.coli nar promoter was not much affected by nitrate concentration in the shake-flask; induction of nar promoter was optimal when Agrobacterium was grown in the presence of 1% nitrate ion at the beginning of culture and when overnight culture was completely grown in the shake-flask before being transferred to other shake-flask; the amount of ${\beta}-galactosidase$ per cell and per medium volume was maximal when Agrobacterium was grown under aerobic condition to $OD_{600}$ of 1.7; then the nar promoter was induced under microaerobic and anaerobic condition made by lowering dissolved oxygen level(DO). After 2-3h of induction in the YEP medium selected as a main culture medium, the specific ${\beta}-galactosidase$ activity became about 17,000 Miller units in the fermentor cluture.

• Analytical Science and Technology
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• v.13 no.4
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• pp.466-473
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• 2000

The complex formation constants (${\beta}_{MLn}$) of potassium and various sodium-selective neutral carriers in solvent polymeric membranes have been determined using solvent polymeric membrane-based optodes and ion-selective electrodes (ISEs). Two different types of PVC-based membranes containing the H^+selective chromoionophore (ETH 5294) with and without a sodium ionophore (4-tert-bntylcalix[4]arenetetraacetic acid tetraethyl ester, ETH 2120, bis[(12-crown-4)methyl] dodecylmethylmalonate or monensin methyl ester) were prepared and their optical responses to either the changes in alkali metal cation (e.g., sodium and potassium) concentrations at a fixed pH (0.05 M Tris-HCl, pH 7.2) or varying pH at a fixed alkali metal cation concentration (0.1 M) were measured. The same type of membranes were also mounted in conventional electrode body and their potentiometric responses to varying pH at a fixed alkali metal cation concentration (0.1 M) were measured. The complex formation constants of the ligand could be calculated from the calibration plots of the relative absorbance vs. the activity ratios of cation and proton ($a_{M^+}/a_{H^+}$) and of the emf vs. pH. It was confirmed that the ratio values of the complex formation constants for the primary and interfering ions are closely related to the experimental selectivity coefficients of ISEs.

• Journal of Sensor Science and Technology
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• v.23 no.3
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• pp.185-191
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• 2014

The width of depletion region in a varactor diode can be modulated by varying a reverse bias voltage. Thus, the preferred characteristics of depletion capacitance can obtained by the change in the width of depletion region so that it can select only the desirable frequencies. In this paper, the TV tuner varactor diode fabricated by hyper-abrupt profile control technique is presented. This diode can be operated within 3.3 V of driving voltage with capability of UHF band tuning. To form the hyperabrupt profile, firstly, p+ high concentration shallow junction with $0.2{\mu}m$ of junction depth and $1E+20ions/cm^3$ of surface concentration was formed using $BF_2$ implantation source. Simulation results optimized important factors such as epitaxial thickness and dose quality, diffusion time of n+ layer. To form steep hyper-abrupt profile, Formed n+ profile implanted the $PH_3$ source at Si(100) n-type epitaxial layer that has resistivity of $1.4{\Omega}cm$ and thickness of $2.4{\mu}m$ using p+ high concentration Shallow junction. Aluminum containing to 1% of Si was used as a electrode metal. Area of electrode was $30,200{\mu}m^2$. The C-V and Q-V electric characteristics were investigated by using impedance Analyzer (HP4291B). By controlling of concentration profile by n+ dosage at p+ high concentration shallow junction, the device with maximum $L_F$ at -1.5 V and 21.5~3.47 pF at 0.3~3.3 V was fabricated. We got the appropriate device in driving voltage 3.3 V having hyper-abrupt junction that profile order (m factor) is about -3/2. The deviation of capacitance by hyper-abrupt junction with C0.3 V of initial capacitance is due to the deviation of thermal process, ion implantation and diffusion. The deviation of initial capacitance at 0.3 V can be reduced by control of thermal process tolerance using RTP on wafer.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.4
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• pp.85-89
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• 2021

AlGaN-based UV-C light-emitting diodes (LEDs) were applied for p-type activation by electrochemical potentiostatic activation (EPA). The p-type activation efficiency was increased by removing hydrogen atoms through EPA treatment using a neutral Mg-H complex that causes high resistance and low conductivity. A neutral Mg-H complex is decomposed into Mg^- and H⁺ depending on the key parameters of solution, voltage, and time. The improved hole carrier concentration was confirmed by secondary ion mass spectroscopy (SIMS) analysis. This mechanism eventually improved the internal quantum efficiency (IQE), the light extraction efficiency, the leakage current value in the reverse current region, and junction temperature, resulting in better UV-C LED lifetime. For systematic analysis, SIMS, Etamax IQE system, integrating sphere, and current-voltage measurement system were used, and the results were compared with the existing N₂-annealing method.

• Journal of agriculture & life science
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• v.53 no.1
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• pp.13-21
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• 2019

This study was carried out to acquire basic data for a long-term hydroponic culture through investigating water and inorganic ion uptake characteristics at different EC level of nutrient solution of three tomato varieties. Three different tomato varieties, the European type(cv. Daphnis), the Asian type(cv. Super Doterang) and cherry type(cv. Minichal), were used for the investigation. Also, the deep flow technique(DFT) was applied. The three different electrical conductivity(EC) level(1.0, 2.0, 3.0, and 4.0 dS·m-1) of hydroponic nutrient solution were used as variable. At a high EC level of nutrient solution, the leaf area and fresh weight decreased in the early stage, and its growth(plant height, leaf number, leaf area, fresh-weight) was poor with salt stress. Result showed that the higher the EC level of the nutrient solution, the lesser was water uptake. The water uptake was not significantly different from varieties in the first survey, but In the second survey, the 'Daphnis' did not show a significant decrease in water uptake in the EC level higher than 2.0 dS·m-1., on the other hand, 'Super Doterang' presented very low water uptake. At a low EC level, N, P, and K, were absorbed more than the concentration of the irrigation water, while Ca, Mg, S uptake were low. At a high EC level, almost ions absorbed less than 50% of the initial concentration of irrigation water. Thus, imbalance among ions was severe at low EC level compared to high EC level. 'Daphnis' was a variety that effectively utilize nutrients under nutrient stress, showing high absorption at low concentration condition and low absorption at high concentration condition. However, 'Daphnis' suffered most seriously by absorbing nutrients excessively.

• Applied Chemistry for Engineering
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• v.18 no.1
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• pp.29-35
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• 2007

Recently, due to narrow margin on design factor of flue gas desulfurization (FGD) systems or aging of systems, some problems such as decrease of $SO_2$ removal efficiency and difficulty on coping with unstable state are arising on FGD systems. On this study, to cope with these problems several methods such as adjustment of reagent pH, inlet $SO_2$ concentration, variation of units of operation pump, installation of liquid distribution ring (LDR) were attempted to increase the $SO_2$ removal using spray type simulated FGD system. Also, sulfite and Al/Fx ion effects on limestone blinding were experimented. When three absorber recirculation pumps were operated, $SO_2$ removal was increased by 12% in comparison with that of two pumps operation. $SO_2$ removal was increased by 2~7% after installation of LDR. Dissolved oxygen increased up to 0.5 ppm and limestone binding effect was alleviated after injection of dibasic acid (DBA) with the concentration of 500 and 1,000 ppm. When $Al^{3+}$ and $F^-$ ions were coexisting, the dissolution rate of limestone was decreased by 20%.