• Title/Summary/Keyword: $K^{+}$ channels

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Distribution Channel Preference Accessing 'Korean Wave' in China : Comparing Official and Unofficial Channel

  • Jia, Shen;Park, Young-Eun;Kim, Myung-Sook
    • Journal of Distribution Science
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    • v.16 no.1
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    • pp.47-58
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    • 2018
  • Purpose - China has become the world's largest market of Korean culture goods. However the distribution and information channel from which Chinese consumers can access to Korean contents remains under-explored. This study aimed to investigate Chinese consumers' information accessing behavior. Research design, data, and methodology - We collected the sample of 800 customers who are exposed to Korean Wave in China. Regression analysis is used to confirm the relationships in the research model. Results - The results showed that official channels such as state owned sites still play a significant role, Chinese consumers prefer to use unofficial channels and the private SNS is the most popular one. It is also found that users with low interests in Korean contents prefer offline/indirect channels while people who are highly immersed into Korean culture and spend longer time on it tend to favor online/unofficial channels. The results confirms that there are some users' characteristics such as gender, age, income and experience of visiting Korea are relevant to explain their propensity to select distribution and information channels for Korean contents. Conclusions - The study enables managers to develop the more effective distribution channel strategies according to the different target consumer groups.

Study On the Six Channels Demonstration Answering the Question in Treatise on Exogenous Febrile Disease (${\ll}$상한론(傷寒論)${\gg}$의 육경변증(六經辨證) 설문에 관한 연구)

  • Park, Min-Kwan;Kim, Min-Yong;Park, Young-Jae
    • The Journal of the Society of Korean Medicine Diagnostics
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    • v.9 no.2
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    • pp.83-93
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    • 2005
  • It is well known that Treatise on Exogenous Febrile Disease is one of the oldest and most authoritative books in Oriental Medicine, suggesting the concept of Exogenous Febrile and Six channels as a theoretical basis of clinical experience and prescription. But, since Thang Thongjing had written the book, the numberous medical practitioners and theorists asserted their various and different views on the concept of Exogenous Febrile and its Six channels. 3UM-3YANG of Treatise on Exogenous Febrile Disease is basically the thing of specialization UM-YANG, eventually UM-YANG are two functional characteristics in human body. It is specialized to 3UM-3YANG by spatial and time criteria Therefore, it is important to apprehend the concept correctly that was written on Treatise on Exogenous Febrile Disease. I'd like to look into a bodily state by answering the question that is easy to access and based on Six Channels.

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Time Division Transmission of Visible Light Channels Using Power Line Frequency (전력선 주파수를 이용한 가시광 채널의 시분할 전송)

  • Lee, Seong-Ho
    • Journal of Sensor Science and Technology
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    • v.23 no.5
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    • pp.349-355
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    • 2014
  • In this paper, we developed a new method to transmit multiple visible light channels in time division mode using the AC power line frequency in order to prevent the crosstalk between adjacent optical signals. Synchronizing pulses are generated from the 220 V power line, and one pulse period is subdivided into several time slots for visible light channels. Each channel transmits data in a predefined time slot without interfering adjacent channels. In experiments, synchronizing pulses with a repetition rate of 240 Hz were generated from the 60 Hz power line, and three VLC channels with a bit rate of 9.6 kbps transmitted data independently using the time slots between synchronizing pulses. This configuration is very useful in constructing time division VLC networks for multiple sensors.

The timing do-skew modeling and design in a high speed digital system (고속 디지털 시스템에서 전달 시간차의 보정 모델링 및 구현)

  • Oh, Kwang-Suhk
    • Proceedings of the KIEE Conference
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    • 2002.11c
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    • pp.601-604
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    • 2002
  • In this paper, the timing do-skew modeling for a high speed logic tester channels is developed. The time delay of each channel in a logic tester are different from other channels and it can produce timing error in a test. To get the best timing accuracy in the test with a logic tester, the timing skew must be compensated. The timing skew of channels is due to the difference of time delay of pin-electronics devices composing channels and length of metal line placed on PCB. The expected timing difference of channels can be calculated according to the specifications of pin electronics devices and strip line modeling of PCB. With the calculated delay time, the timing skew compensation circuit has been designed. With the timing skew compensation circuit, the timing calibration of a logic tester can be peformed easily and automatically without other time measuring instruments. The calibration method can then be directly applied to logic testers in mass production lines.

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Dynamic Characteristics of Gain-Clamped L-band EDFA with Bi-directional Pumps (양방향 펌프구조 고정이득 L-band EDFA의 과도응답 특성)

  • Kim, Ik-Sang
    • The Journal of Engineering Research
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    • v.5 no.1
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    • pp.119-133
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    • 2004
  • The gain-clamped EDFA has been developed to eliminate the output power change of WDM surviving channels to occur with added or dropped channels, which degrades the performance of EDM optical network. It maintains the constant gain of surviving channels when WDM channels are added or dropped in a network amplifying node. In this paper, the bi-directionally pumped gain-clamped EDFA is implemented to compensate the change of the input power by a lasing. The results show that the alsing of a short wavelength and backward propagation is the optimal condition to minimize the transient response of surviving channels in terms of the overshoot and gain saturation sue to the inhomogeneous broadening effect.

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Product Presentation Strategies for Cable Television Home Shopping Channels

  • Kim Dong Hun
    • Journal of Distribution Research
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    • v.1 no.1
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    • pp.223-237
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    • 1996
  • The emergence of the cable television era has spawned the introduction of many new television programming formats such as all-news channels, movie channels, channels catering to cultural events, channels for women, and many others. One of the new programming formats that is expected to have interesting implications for marketing is the home shopping channel. As we have observed in other countries, this new form of distribution may potentially have a major impact on the traditional retail industry. This paper presents a model of home shopping channel viewing behavior. This model is then used to formulate optimal product presentation strategies that may aid managers in the design of home shopping programs. Specifically, by formulating a profit-maximization problem based on tile model, we derive the optimal length of product presentations and explore its properperties through simulating various situations. The discussion of these properties provide insights about making strategic decisions regarding product presentations.

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Effects of hydrogen peroxide on voltage-dependent K+ currents in human cardiac fibroblasts through protein kinase pathways

  • Bae, Hyemi;Lee, Donghee;Kim, Young-Won;Choi, Jeongyoon;Lee, Hong Jun;Kim, Sang-Wook;Kim, Taeho;Noh, Yun-Hee;Ko, Jae-Hong;Bang, Hyoweon;Lim, Inja
    • The Korean Journal of Physiology and Pharmacology
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    • v.20 no.3
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    • pp.315-324
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    • 2016
  • Human cardiac fibroblasts (HCFs) have various voltage-dependent $K^+$ channels (VDKCs) that can induce apoptosis. Hydrogen peroxide ($H_2O_2$) modulates VDKCs and induces oxidative stress, which is the main contributor to cardiac injury and cardiac remodeling. We investigated whether $H_2O_2$ could modulate VDKCs in HCFs and induce cell injury through this process. In whole-cell mode patch-clamp recordings, application of $H_2O_2$ stimulated $Ca^{2+}-activated$ $K^+$ ($K_{Ca}$) currents but not delayed rectifier $K^+$ or transient outward $K^+$ currents, all of which are VDKCs. $H_2O_2-stimulated$ $K_{Ca}$ currents were blocked by iberiotoxin (IbTX, a large conductance $K_{Ca}$ blocker). The $H_2O_2-stimulating$ effect on large-conductance $K_{Ca}$ ($BK_{Ca}$) currents was also blocked by KT5823 (a protein kinase G inhibitor) and 1 H-[1, 2, 4] oxadiazolo-[4, 3-a] quinoxalin-1-one (ODQ, a soluble guanylate cyclase inhibitor). In addition, 8-bromo-cyclic guanosine 3', 5'-monophosphate (8-Br-cGMP) stimulated $BK_{Ca}$ currents. In contrast, KT5720 and H-89 (protein kinase A inhibitors) did not block the $H_2O_2-stimulating$ effect on $BK_{Ca}$ currents. Using RT-PCR and western blot analysis, three subtypes of $K_{Ca}$ channels were detected in HCFs: $BK_{Ca}$ channels, small-conductance $K_{Ca}$ ($SK_{Ca}$) channels, and intermediate-conductance $K_{Ca}$ ($IK_{Ca}$) channels. In the annexin V/propidium iodide assay, apoptotic changes in HCFs increased in response to $H_2O_2$, but IbTX decreased $H_2O_2$-induced apoptosis. These data suggest that among the VDKCs of HCFs, $H_2O_2$ only enhances $BK_{Ca}$ currents through the protein kinase G pathway but not the protein kinase A pathway, and is involved in cell injury through $BK_{Ca}$ channels.

Detection of Mitochondrial ATP-Sensitive Potassium Channels in Rat Cardiomyocytes

  • Cuong, Dang Van;Kim, Na-Ri;Kim, Eui-Yong;Lee, Young-Suk;Kim, Hyun-Ju;Kang, Sung-Hyun;Hur, Dae-Young;Joo, Hyun;Park, Young-Shik;Hong, Yong-Geun;Lee, Sang-Kyung;Chung, Joon-Yong;Seog, Dae-Hyun;Han, Jin
    • The Korean Journal of Physiology and Pharmacology
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    • v.8 no.4
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    • pp.201-206
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    • 2004
  • Mitochondrial ATP-sensitive potassium $(mitoK_{ATP})$ channels play a role in early and late ischemic preconditioning. Nevertheless, the subunit composition of $mitoK_{ATP}$ channels remains unclear. In this study, we investigated the subunit composition of $mitoK_{ATP}$ channels in mitochondria isolated from rat cardiac myocytes. Mitochondria were visualized using the red fluorescence probe, Mitrotracker Red, while $mitoK_{ATP}$ channels were visualized using the green fluorescence probe, glibenclamide-BODIPY. The immunofluorescence confocal microscopy revealed the presence of Kir6.1, Kir6.2 and SUR2 present in the cardiac mitochondria. Western blot analysis was carried to further investigate the nature of $mitoK_{ATP}$ channels. For SUR proteins, a 140-kDa immunoreactive band that corresponded to SUR2, but no SUR1 was detected. For Kir6.2, three bands $({\sim}44,\;{\sim}46,\;and\;{\sim}30\;kDa)$ were detected, and a specific ${\sim}46-kDa$ immunoreactive band corresponding to Kir6.1 was also observed. These observations suggest that the subunits of $mitoK_{ATP}$ channels in rat myocytes include Kir6.1, Kir6.2, and a SUR2-related sulfonylurea-binding protein.

Myometrial relaxation of mice via expression of two pore domain acid sensitive K+ (TASK-2) channels

  • Kyeong, Kyu-Sang;Hong, Seung Hwa;Kim, Young Chul;Choi, Woong;Myung, Sun Chul;Lee, Moo Yeol;You, Ra Young;Kim, Chan Hyung;Kwon, So Yeon;Suzuki, Hikaru;Park, Yeon Jin;Jeong, Eun-Hwan;Kim, Hak Soon;Kim, Heon;Lim, Seung Woon;Xu, Wen-Xie;Lee, Sang Jin;Ji, Il Woon
    • The Korean Journal of Physiology and Pharmacology
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    • v.20 no.5
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    • pp.547-556
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    • 2016
  • Myometrial relaxation of mouse via expression of two-pore domain acid sensitive (TASK) channels was studied. In our previous report, we suggested that two-pore domain acid-sensing $K^+$ channels (TASK-2) might be one of the candidates for the regulation of uterine circular smooth muscles in mice. In this study, we tried to show the mechanisms of relaxation via TASK-2 channels in marine myometrium. Isometric contraction measurements and patch clamp technique were used to verify TASK conductance in murine myometrium. Western blot and immunehistochemical study under confocal microscopy were used to investigate molecular identity of TASK channel. In this study, we showed that TEA and 4-AP insensitive non-inactivating outward $K^+$ current (NIOK) may be responsible for the quiescence of murine pregnant longitudinal myometrium. The characteristics of NIOK coincided with two-pore domain acid-sensing $K^+$ channels (TASK-2). NIOK in the presence of $K^+$ channel blockers was inhibited further by TASK inhibitors such as quinidine, bupivacaine, lidocaine, and extracellular acidosis. Furthermore, oxytocin and estrogen inhibited NIOK in pregnant myometrium. When compared to non-pregnant myometrium, pregnant myometrium showed stronger inhibition of NIOK by quinidine and increased immunohistochemical expression of TASK-2. Finally, TASK-2 inhibitors induced strong myometrial contraction even in the presence of L-methionine, a known inhibitor of stretch-activated channels in the longitudinal myometrium of mouse. Activation of TASK-2 channels seems to play an essential role for relaxing uterus during pregnancy and it might be one of the alternatives for preventing preterm delivery.

[$Ca^{2+}$ Signalling in Endothelial Cells: Role of Ion Channels

  • Nilius, Bernd;Viana, Felix;Kamouchi, Masahiro;Fasolato, Cristina;Eggermont, Jan;Droogmans, Guy
    • The Korean Journal of Physiology and Pharmacology
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    • v.2 no.2
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    • pp.133-145
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    • 1998
  • $Ca^{2+}-signals$ in endothelial cells are determined by release from intracellular stores and entry through the plasma membrane. In this review, the nature of $Ca^{2+}$ entry and mechanisms of its control are reviewed. The following ion channels play a pivotal role in regulation of the driving force for $Ca^{2+}$ entry: an inwardly rectifying $K^+$ channel, identified as Kir2.1, a big-conductance, $Ca^{2+}-activated$ $K^+$ channel (hslo) and at least two $Cl^-$ channels (a volume regulated $Cl^-$ channel, VRAC, and a $Ca^{2+}$ activated $Cl^-$ channel, CaCC). At least two different types of $Ca^{2+}$-entry channels exist: 1. A typical CRAC-like, highly selective $Ca^{2+}$ channel is described. Current density for this $Ca^{2+}$ entry is approximately 0.1pA/pF at 0 mV and thus 10 times smaller than in Jurkat or mast cells. 2. Another entry pathway for $Ca^{2+}$ entry is a more non-selective channel, which might be regulated by intracellular $Ca^{2+}$. Although detected in endothelial cells, the functional role of trp1,3,4 as possible channel proteins is unclear. Expression of trp3 in macrovascular endothelial cells from bovine pulmonary artery induced non-selective cation channels which are probably not store operated or failed to induce any current. Several features as well as a characterisation of $Ca^{2+}$-oscillations in endothelial cells is also presented.

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