• 제목/요약/키워드: Ion Channel

검색결과 442건 처리시간 0.03초

Development of a New Hybrid Silicon Thin-Film Transistor Fabrication Process

  • Cho, Sung-Haeng;Choi, Yong-Mo;Kim, Hyung-Jun;Jeong, Yu-Gwang;Jeong, Chang-Oh;Kim, Shi-Yul
    • Journal of Information Display
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    • 제10권1호
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    • pp.33-36
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    • 2009
  • A new hybrid silicon thin-film transistor (TFT) fabrication process using the DPSS laser crystallization technique was developed in this study to realize low-temperature poly-Si (LTPS) and a-Si:H TFTs on the same substrate as a backplane of the active-matrix liquid crystal flat-panel display (AMLCD). LTPS TFTs were integrated into the peripheral area of the activematrix LCD panel for the gate driver circuit, and a-Si:H TFTs were used as a switching device of the pixel electrode in the active area. The technology was developed based on the current a-Si:H TFT fabrication process in the bottom-gate, back-channel etch-type configuration. The ion-doping and activation processes, which are required in the conventional LTPS technology, were thus not introduced, and the field effect mobility values of $4\sim5cm^2/V{\cdot}s$ and $0.5cm^2/V{\cdot}s$ for the LTPS and a-Si:H TFTs, respectively, were obtained. The application of this technology was demonstrated on the 14.1" WXGA+(1440$\times$900) AMLCD panel, and a smaller area, lower power consumption, higher reliability, and lower photosensitivity were realized in the gate driver circuit that was fabricated in this process compared with the a-Si:H TFT gate driver integration circuit

하수방류수 재이용을 위한 Birm filter + UF 적용시 용도별 사용 가능성 및 막오염 특성 (Possible Uses of Reclaimed Wastewater Effluent Treated Using Birm Filtration Along UF, and Analysis on Membrane Fouling)

  • 정진희;이승철;성낙창;최영익
    • 한국환경과학회지
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    • 제25권11호
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    • pp.1467-1474
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    • 2016
  • In response to the water shortage problem, continued attempts are being made to secure consistent and reliable water sources. Among various solutions to this problem, wastewater effluent is an easy way to secure the necessary supply, since its annual output is consistent. Furthermore, wastewater effluent has the advantage of being able to serve various purposes, such as cleaning, sprinkling, landscaping, river management, irrigation, and industrial applications. Therefore, this study presents the possible use of reclaimed industrial wastewater treated with Birm filters and a UF membrane, along with an analysis on membrane fouling. The preprocessing stage, part of the reclamation process, used Birm filters to minimize membrane fouling. Since this study did not consider heavy metal levels in the treated water, the analyses did not include the criterion for irrigation water quality. However, the wastewater reclaimed by using Birm filters and a UF membrane met every other requirement for reclaimed water quality standards. This indicated that the treated water could be used for cleaning, channel flow for maintenance, recreational purposes, and industrial applications. The analysis on the fouling of the Birm filter and UF membrane required the study of the composition and recovery rate of the membrane. According to SEM and EDX analyses of the UF membrane, carbon and oxygen ion composition amounted to approximately 57%, whereas inorganic matter was not detected. Furthermore, the difference in the recovery rates of the distressed membrane between acidic and alkaline cleaning was more than ~78%, which indicated that organic rather than inorganic matter contributed to membrane fouling.

Association of GRIA1 polymorphisms with ovarian response to human menopausal gonadotropin in Iranian women

  • Golestanpour, Hossein;Javadi, Gholamreza;Sheikhha, Mohammad Hasan
    • Clinical and Experimental Reproductive Medicine
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    • 제47권3호
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    • pp.207-212
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    • 2020
  • Objective: Glutamate ionotropic receptor AMPA type subunit 1 (GRIA1) is a subunit of a ligand-gated ion channel that regulates the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) by controlling the release of gonadotropin-releasing hormone. Few studies have investigated the association between the GRIA1 gene and human infertility. This study evaluated the association of the GRIA1 rs548294 C > T and rs2195450 G > A polymorphisms with the ovarian response to human menopausal gonadotropin (HMG) in Iranian women. Methods: One hundred women with histories of at least 1 year of infertility were included. On the second day of menstruation, patients were injected with HMG; on the third day, blood samples were collected. After hormonal analysis, the GRIA1 rs548294 C > T and rs2195450 G > A genotypes of samples were identified via the restriction fragment length polymorphism method, and on day 9, the number of follicles was assessed via ultrasound. Results: For the GRIA1 rs548294 C > T and rs2195450 G > A single nucleotide polymorphisms, the subjects with CT and GG genotypes, respectively, displayed the highest mean FSH level, LH level, and number of follicles on day 9 of the menstrual cycle (p< 0.05). Significant positive correlations were observed between LH and FSH (p< 0.01), LH and follicle count (p< 0.01), FSH and age (p< 0.05), follicle count and age (p= 0.048), and FSH and follicle count (p< 0.01). Conclusion: This study showed a significant relationship between GRIA1 polymorphisms and ovarian response to the induction of ovulation. Therefore, determining patients' GRIA1 genotype may be useful for improving treatment and prescribing suitable doses of ovulation-stimulating drugs.

고분자 제습로터의 저온재생 성능시험 (Performance Test of Low Temperature Regeneration Polymeric Desiccant Rotor)

  • 이진교;이대영;오명도
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2009년도 하계학술발표대회 논문집
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    • pp.629-632
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    • 2009
  • The polymeric desiccant rotor is made from the super absorbent polymer by ion modification. The moisture sorption capacity of the super desiccant polymer(SDP) is 4 to 5 times larger than those of common desiccant meterials such as silica gel or zeolite. It is also known that SDP can be regenerated even at the relatively low temperature. To fabricate the desiccant rotor, firstly the SDP was laminated by coating the SDP on polyethylene sheet. Then corrugated and rolled up into a rotor. The diameter, the depth, the dimensions of the corrugated channel, etc. were pre-determined from numerical simulation on the heat and mass transfer in the desiccant rotor. The dehumidification performance was tested in a climate chamber. The relevant tests were carried out at the process air inlet temperature of $32^{\circ}C$, the regeneration air inlet temperature of $60^{\circ}C$ and the inlet dew-point temperature of both the process air and the regeneration air of $18.5^{\circ}C$, when the rotation period is long, the moisture sorption is not effective. In the desiccant rotor developed in this study, the optimum rotation period is found about 350s at the regeneration temperature of $60^{\circ}C$. It was found from further experiments that the optimum rotation tends to decreases as the regeneration temperature increases. Meanwhile, the outlet temperature of the process air deceases monotonically as the rotation period increases.

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전기동력 무인항공기용 PMU의 개선 및 제작에 대한 연구 (Study on Production of Power Monitoring Unit for Electric Propulsion UAV)

  • 강진명;정진석;강범수;김장목
    • 한국항공우주학회지
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    • 제45권2호
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    • pp.140-147
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    • 2017
  • 본 논문에서는 전기추진 무인항공기의 동력원으로 주로 사용되고 있는 리튬폴리머 배터리의 상태 모니터링을 위해 기존에 자체 개발한 동력 모니터링 장치인 PMU의 개선 및 제작에 관하여 기술하였다. 개선된 PMU는 비행에 필요한 다양한 센서와 모터의 구동에 안정적인 전압과 전류를 제공하며 모니터링 채널과 온도센서의 추가로 상태 모니터링의 정밀도가 향상되었다. 지상 시험환경을 통해 무인항공기에 탑재되는 PMU의 전압전류 측정값을 보정하고 실제 비행시험을 통해 개선된 성능을 확인하였다.

Endothelial Ca2+ signaling-dependent vasodilation through transient receptor potential channels

  • Hong, Kwang-Seok;Lee, Man-Gyoon
    • The Korean Journal of Physiology and Pharmacology
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    • 제24권4호
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    • pp.287-298
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    • 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.

기니픽 심근의 전기생리학적 특성에 미치는 α1-Adrenoceptor 자극효과 (Effects of α1-adrenoceptor stimulation on ventricular electrophysiological properties of guinea pigs)

  • 김진상
    • 대한수의학회지
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    • 제33권2호
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    • pp.199-209
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    • 1993
  • The effects of ${\alpha}_1$-adrenergic stimulation on membrane potential, intracellular sodium activity $(a_N{^i{_a}})$, and contractility were investigated in the isolated papillary muscle of euthyroid, hyperthyroid, and hypothyroid guinea pigs. Cardiac alterations in the thyroid state have been shown to induce marked changes in action potential characteristics, the most pronounced shortening of action potential duration by hyperthyroidism and an increase in duration by hypothyroidism. $10^{-5}M$ Phenylephrine produced a decrease in $(a_N{^i{_a}})$ in euthyroid and hypothyroid preparations, but an increase in $(a_N{^i{_a}})$ in hyperthyroid ones. The major findings were that phenylephrine produced a stronger positive inotropic effect(PIE) without initial negative inotropic effect(NIE) in hyperthyroid preparations, while phenylephrine produced markedly NIE in hypothyroid ones. The alterations in membrane potential, $(a_N{^i{_a}})$, and contractility were abolished by $3{\times}10^{-5}M$ prazosin in hypothyroidism. In hypothyroid ventricular muscle, the decrease in $(a_N{^i{_a}})$ caused by phenylephrine were not abolished or reduced by $10^{-5}M$ strophanthidin, $10^{-5}M$ TTX, $3{\times}10^{-4}M$ lidocaine, or $100^{-5}M$ verapamil. These results indicate that the ${\alpha}_1$-adrenoceptor-mediated decrease in $(a_N{^i{_a}})$ is not associated with a stimulation of the $Na^+$-$K^+$ pump, inhibition of the $Na^+$ or $Ca^+$ channel in hypothyroid ventricular muscle. $10^{-5}M$ Phenylephrine decreased $(a_N{^i{_a}})$ but increased $(a_N{^i{_a}})$ in the presence of a PKC activator phorbol dibutyrate$(PDB_u)$. In conclusion, it is suggested that the following sequence of events in response to phenyleplhane occur in guinea pig ventricular muscle. First, changes in thyroid state may contribute to the ventacular electrophysiological propeties or ion transport system. Second, the adrenoceptor-mediated initial transient NIE may be associated with the decrease in $(a_N{^i{_a}})$ by PKC activation.

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Phosphate Number and Acyl Chain Length Determine the Subcellular Location and Lateral Mobility of Phosphoinositides

  • Cho, Hana;Kim, Yeon A;Ho, Won-Kyung
    • Molecules and Cells
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    • 제22권1호
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    • pp.97-103
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    • 2006
  • Phosphoinositides are critical regulators of ion channel and transporter activity. There are multiple isomers of biologically active phosphoinositides in the plasma membrane and the different lipid species are non-randomly distributed. However, the mechanism by which cells impose selectivity and directionality on lipid movements and so generate a non-random lipid distribution remains unclear. In the present study we investigated which structural elements of phosphoinositides are responsible for their subcellular location and movement. We incubated phosphatidylinositol (PI), phosphatidylinositol 4-monophosphate (PI(4)P) and phosphatidylinositol 4,5-bisphosphate ($PI(4,5)P_2$) with short or long acyl chains in CHO and HEK cells. We show that phosphate number and acyl chain length determine cellular location and translocation movement. In CHO cells, $PI(4,5)P_2$ with a long acyl chain was released into the cytosol easily because of a low partition coefficient whereas long chain PI was released more slowly because of a high partition coefficient. In HEK cells, the cellular location and translocation movement of PI were similar to those of PI in CHO cells, whereas those of $PI(4,5)P_2$ were different; some mechanism restricted the translocation movement of $PI(4,5)P_2$, and this is in good agreement with the extremely low lateral diffusion of $PI(4,5)P_2$. In contrast to the dependence on the number of phosphates of the phospholipid head group of long acyl chain analogs, short acyl chain phospholipids easily undergo translocation movement regardless of cell type and number of phosphates in the lipid headgroup.

매크로셀과 마이크로셀이 중첩된 W-CDMA 무선가입자망에서 마이크로셀의 용량 산정 (Capacity esitmation of microcell in macro/microcell overlaid W-CDMA WLL system)

  • 손성찬;노재성;김수용;조성준
    • 한국통신학회논문지
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    • 제23권9A호
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    • pp.2153-2164
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    • 1998
  • This paper has presented the parameters for the coexistence between two systems in macro/microcell ovelaid W-CDMA WLL (wideband CDMA wireless local loop) and has calculated the capacity of forward/reverse link in microcell. To produce the capacity for analyzing system interference effects, we have shown tables and graphs with the parameters sucyh as RF channel bandwidth of WLL(W), the transmission rate of service message(R), the required signal power to noise power ratio( $E_{b/}$ $N_{0}$) for achieving accepatable error rate, te user number ( $N_{W1}$, $N_{W2}$) of the neighboring system, the signal power to interference power ratio(.GAMMA.$_{C1B}$, .GAMMA.$_{C2B}$) of the neighboring system, the normalized distance(d) between microcell and macrocell base-station, and microcell to macrocell radius ratio ( $R_{d}$). From the results, we have convinced that the capacity of microcell diminishes as increasing the user number ( $N_{W2}$) in macrocell, increasing the microcell radius, and decreasing the normalized distance(d) between microcell and macrocell base-station. Especially, we have known that when $R_{d}$=0.1, $N_{W2}$ must be below 24 at .GAMMA.$_{C2B}$ = 0 dB and below 8 at .GAMMA.$_{C2B}$ = 4 dB for the acceptable capacity raito to be over 80%. Therfore, this paper is usefult to design microcell W-CDMA WLL for accommodating more user number under the interference effects of macrocell W-CDMA WLL and is expected to be reference in power control if base-station.ation.ion.ation.ation.

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당근 현탁배양 세포에서 $Ca^{2+}$과 Polyamines가 Cell Wall 합성에 관여하는 $\beta-Glucan$ Synthetase II 활성에 미치는 영향 (Effect of $Ca^{2+}$ and Polyamines on the Activity of $\beta-Glucan$ Synthetase II Related to Cell Wall Synthesis in Carrot Suspension Cultured Cells)

  • 표병식
    • Journal of Plant Biology
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    • 제31권2호
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    • pp.91-100
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    • 1988
  • The effect of Ca2+ and polyamines on the activity $\beta$-glucan synthetase II(GSII) related to cell wall synthesis was studied in carrot suspension cultured cells. The activity of GS II is four times higher than that of $\beta$-glucan synthetase I in carrot suspension cultured cells and in vitro expreiment, the activity of GSII was increased in response to increase in concentration of Ca2+ and polyamines. When carrot suspension cultured cells were incubated together with Ca2+ and polyamines, the GSII activity was high at 0.1mM of Ca2+ and 1mM of putrescine. Also, polycationic poly-L-lysine and poly-L-ornithine increased about 50% the GSII activity than that of the control, respectively. These results may imply that Ca2+ and polyamines were related to the enzyme activity as a polycationic nature. In addition, verapamil as the calcium channel blocker and flunarizine as an antagonist of calcium mechanism in cytoplasm decreased GSII activity ramarkably, Ca2+ and calmodulin stimulated GSII activity as Ca2+ of free ion rather than Ca2+ calmodulin complex. The effect of 2,4-D on the GSII activity in culture medium is shown to be low at 0.1mg per liter and GSII activity increased about 30% more than that of the 0.1mg/l at the range of 0.3-1.0mg per litere. Cummulative results suggest that Ca2+ and polyfamines stimulate the cell wall synthesis by means of the enhancement of GSII activity responsible for synthesizing the cell wall components.

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