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주파수 효율 및 성능 향상을 위한 Frequency Slope Modulated Chirp 신호를 이용한 UWB 시스템
김정현, 김지현, 유철우, Kim. Jung-Hyun, Kim. Ji-Hyun, You. Cheol-woo 한국통신학회 한국통신학회논문지. The journal of Korea Information and Communications Society. 무선통신 6 Pages
한국통신학회 한국통신학회논문지. The journal of Korea Information and Communications Society. 무선통신 2011, Vol.36 127-132 (6 pages)
본 논문은 Chirp 신호가 변조된 UWB frequency slope를 이용한 거리 측정 기술 및 통신 시스템을 제안하였다. 오직 up-chirp 만 사용하거나 혹은 (주파수 간) 동일한 주파수 변화도(frequency sweeping rate)를 가진 down-chirp 만 사용하는 대신에, 제안된 시스템은 주파수 도약을 이용하여 서로 다른 주파수 변화도를 가지는 여러 Chirp 신호를 사용한다. 제안된 시스템은 데이터 전송 속도를 증가시킬 수 있고 동시에 사용자들이 사용한 sequence 간에 간섭도 줄일 수 있기 때문에 기존 통신 거리 측정 전략보다도 성능이 좋다. 본... -
pH-dependent modulation of intracellular free magnesium ions with ion- selective electrodes in papillary muscle of guinea pig
Shang-Jin Kim, In-Gook Cho, Hyung-Sub Kang, Jin-Shang Kim 대한수의학회 Journal of Veterinary Science 6 Pages
대한수의학회 Journal of Veterinary Science 2006, 제 7권 제 1호 5 31-36 (6 pages)
NH4Cl. All the experiments were at constant [pH]o of 7.4. For the control, the choline chloride was added to the Thyroid solution. ..PAGE:5 pH-dependent modulation of intracellular free magnesium ions 35 increase in [Mg 2+]i. Nevertheless, the acidification-induced modulation in the [Mg 2+]i coupled with HCO 3 such as Mg 2+/HCO 3 cotransport in sarcolemma and mitochondrial membrane [29] and with H... A change in pH can alter the intracellular concentration of electrolytes such as intracellular Ca2+ and Na+ ([Na+]i) that are important for the cardiac function.For the determination of the role of pH in the cardiac magnesium homeostasis, the intracellular Mg 2+ concentration ([Mg 2+]i), membrane potential and contraction in the papillary muscle of guinea pigs using ion-selective electrodes changing extracellular pH ([pH]o)or intracellular pH ([pH ]i )were measured in this study. A high... -
Graphene field-effect transistor for radio-frequency applications : review
Jeong-Sun Moon 한국탄소학회 Carbon Letters 6 Pages
한국탄소학회 Carbon Letters 2012, Vol.13 No.1 2 17-22 (6 pages)
technologies. 5. Conclusions While it is early in the stage of development to clearly forecast its impact, graphene FETs could potentially offer performance benefts in RF systems including LNAs, frequency multipliers, mixers and high-speed radiometers. The future success of the RF circuit applications depends on high-quality material growth on large-wafer scale, vertical and lateral scaling... -
Antidepressant drug paroxetine blocks the open pore of Kv3.1 potassium channel
HyangMiLee, OkHeeChai, SangJuneHahn, BokHeeChoi 대한생리학회-대한약리학회 The Korean Journal of Physiology & Pharmacology 10 Pages
대한생리학회-대한약리학회 The Korean Journal of Physiology & Pharmacology 2018, Vol.22 No.1 8 71-80 (10 pages)
the paroxetine-induced inhibition of GIRK and TREK could render neurons more excitable. In addition to these channels, various types of ion channels are also involved in the modulation of spike frequency and membrane excitability. However, it is unclear whether and how paroxetine affects such diverse channels related to neuronal excitation. Kv3.1 channels, one of the Shaw-type voltage-gated... determine whether paroxetine, a very potent selective serotonin reuptake inhibitor (SSRI), interacts with ion channels that modulate neuronal excitability, we examined the effects of paroxetine on Kv3.1 potassium channels, which contribute to high-frequency firing of interneurons, using the whole-cell patch-clamp technique. Kv3.1 channels were cloned from rat neurons and expressed in Chinese hamster ovary cells. Paroxetine reversibly reduced the amplitude of Kv3.1 current, with an IC50 value of... -
Effects of acidic pH on voltage-gated ion channels in rat trigeminal mesencephalic nucleus neurons
Jin-EonHan, Jin-HwaCho, In-SunChoi, Do-YeonKim, Il-SungJang 대한생리학회-대한약리학회 The Korean Journal of Physiology & Pharmacology 9 Pages
대한생리학회-대한약리학회 The Korean Journal of Physiology & Pharmacology 2017, Vol.21 No.2 9 215-223 (9 pages)
acutely isolated Vmes neurons. The mechanisms underlying the acidic modulation of voltage-gated ion channels are still unknown; however, an acidic pH may affect the various ion channels tested in this study either directly or indirectly. For example, an acidic pH indirectly affects these ion channels by activating ASICs, since Vmes neurons express multiple ASIC subtypes [18,19,24]. However,... 6.0 solution showed complex modulation of the current-voltage and conductance-voltage relationships, the midpoint voltages for the activation of HCN channels were not changed by acidic pH. On the other hand, voltage-dependent Ca2+ channels were significantly inhibited by an acidic pH. The application of an acidic pH solution significantly shifted the current-voltage and conductance-voltage relationships to the depolarization range. The modulation of several voltage-dependent ion channels by an... -
Potassium Currents in Isolated Deiters' Cells of Guinea Pig
JongWooChung, EuiCholNam, WonTaeKim, JaeBoumYoum, ChaeHunLeem 대한생리학회-대한약리학회 The Korean Journal of Physiology & Pharmacology 10 Pages
대한생리학회-대한약리학회 The Korean Journal of Physiology & Pharmacology 2013, Vol.17 No.6 10 537-546 (10 pages)
and are suggested to play an important role in biochemical and mechanical modulation of outer hair cells. We successfully isolated functionally different K + currents from Deiters’ cells of guinea pig using whole cell patch clamp technique. With high K + pipette solution, depolarizing step pulses activated strongly outward rectifying currents which were dose-dependently blocked by clofilium,... Deiters' cells are the supporting cells in organ of Corti and are suggested to play an important role in biochemical and mechanical modulation of outer hair cells. We successfully isolated functionally different K+ currents from Deiters’ cells of guinea pig using whole cell patch clamp technique. With high K+ pipette solution, depolarizing step pulses activated strongly outward rectifying currents which were dose-dependently blocked by clofilium, a class III anti-arrhythmic K+ channel blocker.... -
Bile Acid Inhibition of N-type Calcium Channel Currents from Sympathetic Ganglion Neurons
HyeKyungLee, KyoungHwaLee, Eui-SicCho 대한생리학회-대한약리학회 The Korean Journal of Physiology & Pharmacology 6 Pages
대한생리학회-대한약리학회 The Korean Journal of Physiology & Pharmacology 2012, Vol.16 No.1 4 25-30 (6 pages)
by alte ring channel gating. Other single channel properties such as current-voltage relation- ship, unitary slope conductance, single channel current am- plitude, open times and shut times were unaffected by CA. CA increased the frequency of null (Figs. 1 and 3) and con- sequently decreased Po. The nu ll sweeps appeared to be clustered, suggesting that an open state is not attainable for a... the control recorded without CA. Other single channel properties including slope conductance, single channel current amplitude, open and shut times were not significantly affected by CA being present. The results suggest that CA could modulate N-type Ca2＋ channel gating at a concentration as low as 10－6 M. Bile acids have been shown to activate nonselective cation conductance and depolarize the cell membrane. Under pathological conditions with increased circulating bile acids, CA suppression... -
Lysophosphatidylcholine Increases Ca2+ Current via Activation of Protein Kinase C in Rabbit Portal Vein Smooth Muscle Cells
SeungsooJung, YounghoLee, SungsikHan, YoungwhanKim, TaiksangNam, DucksunAhn 대한생리학회-대한약리학회 The Korean Journal of Physiology & Pharmacology 4 Pages
대한생리학회-대한약리학회 The Korean Journal of Physiology & Pharmacology 2008, Vol.12 No.1 5 31-34 (4 pages)
vascular smooth muscle cells, although this relationship has not yet been investigated in these ce lls. The aims of the present study were to examine the LPC-induced modulation of I Ca(L) in smooth muscle cells and to investigate the possible role of PKC in this modulation. ..PAGE:2 32 SS Jung, et al Fig. 1. (A) Plot of Ca 2+ currents evoked by repetitive step depolarization from －80 mV to 0... Lysophosphatidylcholine (LPC), a metabolite of membrane phospholipids by phospholipase A2, has been considered responsible for the development of abnormal vascular reactivity during atherosclerosis. Ca2+ influx was shown to be augmented in atherosclerotic artery which might be responsible for abnormal vascular reactivity. However, the mechanism underlying Ca2+ influx change in atherosclerotic artery remains undetermined. The purpose of the present study was to examine the effects of LPC on... -
Open Channel Block of Kv3.1 Currents by Genistein, a Tyrosine Kinase Inhibitor
BokHeeChoi, JiHyunPark, SangJuneHahn 대한생리학회-대한약리학회 The Korean Journal of Physiology & Pharmacology 8 Pages
대한생리학회-대한약리학회 The Korean Journal of Physiology & Pharmacology 2006, Vol.10 No.2 3 71-78 (8 pages)
rect modulation of Kv3.1 channels by genistein in a phosphorylation-independent manner. METHODS Stable transfection and cell culture Rat brain Kv3.1 channels stably expressed in CHO cells were used in the present study (Choi et al, 2001). The method for establishment of Kv3.1 expression in CHO cells is briefly described as follows. The cDNA of Kv3.1 (Luneau et al, 1991) was subcloned into... can close. Genistein-induced block was voltage-dependent, increasing in the voltage range (20 mV∼0 mV) for channel opening, suggesting an open channel interaction. Genistein (20μM) produced use-dependent block of Kv3.1 at a stimulation frequency of 1 Hz. The voltage dependence of steady-state inactivation of Kv3.1 was not changed by 20μM genistein. Our results indicate that genistein blocks directly Kv3.1 currents in concentration-, voltage-, time-dependent manners and the action of... -
Direct Block of Cloned K+ Channels, Kv1.5 and Kv1.3, by Cyclosporin A, Independent of Calcineurin Inhibition
BokHeeChoi, SangJuneHahn 대한생리학회-대한약리학회 The Korean Journal of Physiology & Pharmacology 10 Pages
대한생리학회-대한약리학회 The Korean Journal of Physiology & Pharmacology 2005, Vol.9 No.6 7 353-362 (10 pages)
on a millisecond time scale. Because modulation of ion channels by phosphorylation takes seconds to minutes (Chung & Schlichter, 1997; Choi et al, 2002; Williams et al, 2002), it is again likely that the rapid current reduction was not due to involvement of second messenger pathways such as, phosphorylation and de phosphorylation, but rather a direct action on Kv1.5 channels. In principle,... The interaction of cyclosporine A (CsA), an immunosuppressant, with rat brain Kv1.5 (Kv1.5) channels, which were stably expressed in Chinese hamster ovary cells, was investigated using the whole-cell patch-clamp technique. CsA reversibly blocked Kv1.5 currents at 50 mV in a reversible concentration- dependent manner with an apparent IC50 of 1.0μM. Other calcineurin inhibitors (cypermethrin, autoinhibitory peptide) had no effect on Kv1.5 and did not prevent the inhibitory effect of CsA....