• Bulletin of the Korean Chemical Society
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• v.23 no.5
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• pp.663-664
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• 2002

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10A
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• pp.1521-1528
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• 2000

In this paper we analyze the performance of a DS/CDMA system in LEO mobile satellite channels. The channel uses the Extended Suzuki model which is the product of a Rician distribution having a LOS component and a lognormal distribution due to shadowing. We assume that the signal transmitted from the satellite to the mobile undergoes the same fading for the whole coverage of signal's beam. The average bit error probabilities of double coverage system is calculated in this paper. The interference resulting from the reference satellite is calculated for mobile located in the middle of the double coverage region whereas the additive interference from next-satellite is included for mobile located in the edge of the double coverage region. The performance of the mobile's receiving signal is dependent on shadowing and the interference of the next-satellite. We can obtain an obtain an improved average bit error probability by using dual diversity over the conventional correlated receiver for similar shadowing conditions in the coverage area of the satellite channel.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.413-414
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• 1996

A 230 GHz SIS tunnel junction receiver has been being developed for radio astronomy in Nagoya University. In this heterodyne receiver, we use a $\~$1/3 reduced hight rectangular waveguide SIS mixer with two tuning elements as front end. The mixer block with SIS junction was cooled to 4K with a closed cycle He-gas refrigerator. So far, a double sideband receiver noise temperature lower than l00K in 222-237 GHz is obtained. The receiver exhibits a best DSB noise temperature of 69K at 236 GHz as well as 228 GHz.

• Macromolecular Research
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• v.15 no.3
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• pp.216-220
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• 2007

A new polyfluorene-based copolymer having 2-ethylhexyloxy-5-methoxy-l,4-phenylene as an electron donating group and 2,5-diphenyl-oxadiazole as an electron withdrawing group was synthesized by the Suzuki coupling reaction. The obtained copolymer was characterized by $^1H-NMR,\;^{13}C-NMR$, and IR-spectroscopy. The weight average molecular weight ($M_w$) of the obtained polymer was 18,600 with a polydispersity index of 1.5. The maximum photoluminescence of the solution and film of the polymer was observed at 453 nm and 456 nm, respectively. A double-layer device with the configuration, ITO/PEDOT/copolymer/Al, emitted blue light at 460 nm.

• Clinical Endoscopy
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• v.56 no.5
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• pp.650-657
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• 2023

Background/Aims: Endoscopic ultrasound gallbladder drainage (EUS-GBD) is gaining attention as a treatment method for cholecystitis. However, only a few studies have assessed the outcomes of permanent stenting with EUS-GBD. Therefore, we evaluated the clinical outcomes of permanent stenting using EUS-GBD. Methods: This was a retrospective, single-center cohort study. The criteria for EUS-GBD at our institution are a high risk for surgery, inability to perform surgery owing to poor performance status, and inability to obtain consent for emergency surgery. EUS-GBD was performed using a 7-Fr double-pigtail plastic stent with a dilating device. The primary outcomes were the recurrence-free rate of cholecystitis and the late-stage complication-avoidance rate. Secondary outcomes were technical success, clinical success, and procedural adverse events. Results: A total of 41 patients were included in the analysis. The median follow-up period was 168 (range, 10-1,238) days. The recurrence-free and late-stage complication-avoidance rates during the follow-up period were 95% (38 cases) and 90% (36 cases), respectively. There were only two cases of cholecystitis recurrence during the study period. Conclusions: EUS-GBD using double-pigtail plastic stent was safe and effective with few complications, even in the long term, in patients with acute cholecystitis.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.1
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• pp.1-8
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• 2001

Hyperpolarization of arterial smooth muscle by acetylcholine is considered to be produced by the release of an unidentified chemical substance, an endothelium-derived hyperpolarizing factor (EDHF). Several chemicals have been proposed as the candidate for EDHF. However, none of them fulfil completely the nature and property of EDHF. Ultrastructural observation with electron microscope reveals that in some arteries, gap junctions are formed between endothelial and smooth muscle cells. In small arterioles, injection of gap junction permeable dyes into an endothelial cell results in a distribution of the dye to surrounding cells including smooth muscle cells. These observations allow the speculation that myoendothelial gap junctions may have a functional significance. Simultaneous measurement of the electrical responses in both endothelial and smooth muscle cells using the double patch clamp method demonstrates that these two cell types are indeed electrically coupled, indicating that they behave as a functional syncytium. The EDHF-induced hyperpolarization is produced by an activation of $Ca^{2+}-sensitive\;K^+-channels$ that are inhibited by charybdotoxin and apamin. Agonists that release EDHF increase $[Ca^{2+}]_i$ in endothelial cells but not in smooth muscle cells. Inhibition of gap junctions with chemical agents abolishes the agonist-induced hyperpolarization in smooth muscle cells but not in endothelial cells. All these observations can be explained if EDHF is an electrotonic signal propagating from endothelium to smooth muscle cells through gap junctions.