• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.294-294
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• 2005

• Proceedings of the PSK Conference
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• 2002.04a
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• pp.126.1-126.1
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• 2002

• Journal of the Korea Computer Industry Society
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• v.2 no.8
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• pp.1063-1068
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• 2001

In this paper, we designed a high resolution six channel DSB modulator of Acousto-Optic effect generator make use of DDS technology. Also, configured seamless connection for other instruments to use IEEE-488 bus interface. We programmed the device driver for DDS and DAC control by 80C51 assembler language. And, high resolution 6 channel DSB modulator has improved the important characteristics of that the frequency tuning range, the resolution, the switching time. This DSB modulator system can use high precision frequency synthesizer for instruments.

• Journal of Biomedical Engineering Research
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• v.38 no.1
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• pp.1-8
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• 2017

The successful synthesis of hyaluronic acid micro-threads is very promising approach for the broad application in tissue engineering such as dermal fillers. Because hyaluronic acid has the excellent biocompatibility and ability to maintain the moisture of up to several hundred times its own weight. In order to generate the hyaluronic acid micro-threads in microfluidic system, we employed two-phase flow microfluidic chip to make a rapid synthesis of the hyaluronic acid hydrogel. Hyaluronic acid was mixed with 0.02N NaOH solution and 1, 4-Butanediol diglycidyl ether (BDDE) solution and then injected into core channel. The ethanol was used for the 3-dimensional micro-thread formation in sheath channel. We manipulated the diameter of HA micro-threads using controlling of flow rates in microfluidic chip, and showed the feasibility of immobilization in HA micro-threads with florescent substances. Also, the generated HA micro-threads were evaluated and showed the suitable properties with tensile strength, bending property, and swelling profiles for dermal fillers. As a result, we suggested an innovative method for microfluidic chip-based HA micro-threads which could safely be applied as dermal filler in tissue engineering.

• YAKHAK HOEJI
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• v.59 no.4
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• pp.177-183
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• 2015

The mechanism of melanogenesis induced by cyclosporin A (CsA) was investigated in B16 melanoma cells. CsA stimulated the production of melanin in a dose-dependent manner in the cells. In addition, CsA increased intracellular $Ca^{2+}$ concentration in a dose-related fashion. Treatment with BAPTA/AM, an intracellular $Ca^{2+}$ chelator significantly inhibited the CsA-induced intracellular melanin synthesis. CsA profoundly induced $Cl^-$ efflux, which was significantly blocked by niflumic acid (NFA) and flufenamic acid (FFA), specific and nonspecific inhibitors of $Ca^{2+}$-activated $Cl^-$ channels (CaCCs), respectively. Furthermore, these inhibitors of CaCCs significantly inhibited the CsA-induced stimulation of melanin synthesis. Taken together, these results suggest that the activation of CaCCs may play an important role in the CsA-induced stimulation of melanin synthesis in B16 cells. These results further suggest that CaCCs may be a good target for the management of hyperpigmentation of the skin reported in the patients treated with CsA.

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.2031-2035
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• 2010

A triple-probe channel type chemosensor based on an $NO_2S_2$-macrocycle functionalized with phenyltricyanovinyl group was synthesized and its sensing characteristics were examined. The pink-red solution of L changed selectively to pale yellow upon addition of $Hg^{2+}$. The selective fluorometric response of L to all the tested metal ions was studied. The results showed that a large enhancement of the fluorescence of L was observed only in the case of $Hg^{2+}$. In addition, L showed large anodic shift (~ 0.3 V) for the addition of excess $Hg^{2+}$. Through above three observed results by the different techniques, we confirmed that the proposed chemosensor acts as the multiple-probe channel sensing material. The crystal structure of mercury(II) nitrate complexs of L which shows a 1-D polymer network with a formula $[Hg_2(L)_2(NO_3)_2({\mu}-NO_3)_2]_n$ was also reported.

• The Korea Journal of Herbology
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• v.22 no.2
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• pp.181-188
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• 2007

Objectives : This study was to verify the Attributive Channel theory of herbal medicine. Methods : [13lI]iodocurcumin was synthesized, separated, and refined from curcumin, the major component of Curcuma species, followed by observing the biodistribution in an organism. Especially, from the fact that curcumin has shown to possess potent anti-carcinogenic properties, the biodistribution in the carcinogenesis organism was analyzed. Result : Iodocurcumin 23mg was obtained through column chromatography after a reaction with 50mg of Curcumin and ICl. The nominal yield of [13lI]iodocurcumin synthesis was 35% when checked with radioactive layer of chromatography. [13lI]iodocurcumin was most largely distributed in the stomach of a BALB/c mouse and a C57BL/6 mouse transplanted with Lewis lung carcinoma cell. Conclusion : The fact that [13lI]iodocurcumin was most largely distributed in the stomach was related with the Attributive Channel theory. And there was no significant finding related to tumor cells.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.5
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• pp.361-365
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• 2009

Effects of quercetin, a kind of flavonoids, on the vasodilating actions were investigated. Among the mechanisms for quercetin-induced vasodilatation in rat aorta, the involvement with the $Ca^{2+}$ activated $K^+$ ($K_{Ca}$) channel was examined. Pretreatment with NE ($5\;{\mu}M$) or KCl (60 mM) was carried out and then, the modulation by quercetin of the constriction was examined using rat aorta ring strips (3 mm) at $36.5^{\circ}C$. Quercetin (0.1 to $100\;{\mu}M$) relaxed the NE-induced vasoconstrictions in a concentrationdependent manner. NO synthesis (NOS) inhibitor, NG-monomethyl-L-arginine acetate (L-NMMA), at $100\;{\mu}M$ reduced the quercetin ($100\;{\mu}M$)-induced vasodilatation from $97.8{\pm}3.7%$ (n=10) to $78.0{\pm}11.6%$ (n=5, p<0.05). Another NOS inhibitor, L-NG-nitro arginine methyl ester (L-NAME), at $10\;{\mu}M$ also had the similar effect. In the presence of both $100\;{\mu}M$ L-NMMA and $10\;{\mu}M$ indomethacin, the quercetin-induced vasodilatation was further attenuated by $100\;{\mu}M$ tetraethylammonium (TEA, a $K_{Ca}$ channel inhibitor). Also TEA decreased the quercetin-induced vasodilatation in endothelium-denuded rat aorta. Used other $K_{Ca}$ channel inhibitors, the quercetin-induced vasodilatation was attenuated by $0.3\;{\mu}M$ apamin (a SK channel inhibitor), but not by 30 nM charybdotoxin (a BK and IK channel inhibitor). Quercetin caused a concentration-dependent vasodilatation, due to the endotheliumdependent and -independent actions. Also quercetin contributes to the vasodilatation selectively with SK channel on smooth muscle.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.6
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• pp.101-108
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• 2005

In this paper, we proposed a new algorithm of pulse generation and detection for the UWB multimedia communication system. The existing UWB systems using Gaussian pulse have some difficulties to cope with bandwidth limitation and frequency transition. In this paper, we introduce a new pulse generation method, which is able to control the bandwidth and center frequency that applies to the frequency modulation method, thus the proposed algorithm could improve the detection performance of receiving. And we proposed the multi channel transmission algorithm which transmits 1 channel synthesized at same time using the wavelet synthesis filter. Because of wavelet filter's perfect reconstruction property, the BER(Bit Error Rate) of transmission data is not changed by the number of accessed user. BER is changed only the property of channel transmission. By the results of simulation, when shift SNR from 2dB to 8dB on AWGN channel, we confirmed that the proposed algerian has $3.9063{\times}10^{-4}$ BER at 4dB SNR(AWGN channel).

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.277.1-277.1
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• 2016

We report on synthesis of large-area MoS2 using chemical vapor deposition (CVD). Relatively uniform MoS2 are obtained. To fabricate field-effect transistor (FET) devices, MoS2 films are transferred to another SiO2/Si substrate using polystyrene (PS) and patterned using oxygen plasma. In addition, to reduce contact resistance, synthesis of graphene used as channel. Device characteristics are presented and compared with the reported results.