• Journal of Life Science
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• v.28 no.5
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• pp.547-554
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• 2018

Flaxseed (Linum usitatissimum L.), also called linseed and one of the raw materials for making linen, is rich in omega-3 fatty acids, vegetable estrogen, ${\alpha}$-linolenic acid, and dietary fiber. Studies on flaxseed have reported various additional effects, such as the inhibition of cholesterol, blood clotting, and tumor growth. In this study, we investigated the functional components of flaxseed fermented with lactic-acid bacteria. Lactic-acid bacteria was inoculated into heat-treated (roasted) flaxseed and fermented at $37^{\circ}C$ for 72 hr. The fermented flaxseed was extracted with 70% ethanol and the antioxidant effect of the fermented extracts according to the lactic-acid bacteria was analyzed. It was confirmed that the total polyphenol contents had expanded by about 1.5-8 times, and the total flavonoid contents had increased around 1.2 times in the case of fermented flaxseed with lactic-acid bacteria compared to non-fermented flaxseed (NFFS). DPPH radical scavenging and superoxide dismutase-like activities had increased around 5.6 and 2.3 times, respectively, in the fermented flaxseed compared to the NFFS at 100 ppm concentration. The study concluded that fermentation of flaxseed with lactic-acid bacteria is possible and that it is effective to increase the antioxidant effects of flaxseed. These results can be applied to the development of improved foods and cosmetic materials.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.8
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• pp.461-465
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• 2016

n-type silicon shows the better tolerance towards metal impurities with a higher minority carrier lifetime compared to p-type silicon substrate. Due to better lifetime stability as compared to p-type during illumination made the photovoltaic community to switch toward n-type wafers for high efficiency silicon solar cells. We fabricated the front electrode of the n-type solar cell with AgAl paste. The electrodes characteristics of the AgAl paste depend on the contact junction depth that is closely related to the firing temperature. Metal contact depth with p+ emitter, with optimized depth is important as it influence the resistance. In this study, we optimize the firing condition for the effective formation of the metal depth by varying the firing condition. The firing was carried out at temperatures below $670^{\circ}C$ with low contact depth and high contact resistance. It was noted that the contact resistance was reduced with the increase of firing temperature. The contact resistance of $5.99m{\Omega}cm^2$ was shown for the optimum firing temperature of $865^{\circ}C$. Over $900^{\circ}C$, contact junction is bonded to the Si through the emitter, resulting the contact resistance to shunt. we obtained photovoltaic parameter such as fill factor of 76.68%, short-circuit current of $40.2mA/cm^2$, open-circuit voltage of 620 mV and convert efficiency of 19.11%.

• Restorative Dentistry and Endodontics
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• v.28 no.4
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• pp.341-347
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• 2003

This study was conducted to evaluate the temperature rise on the root surface while the root canal is being obturated using continuous wave of condensation technique. Maxillary central incisor was prepared for repeated canal obturation. Ten thermocouples (Omega Engineering Inc., Stanford, USA) were placed at 1 mm increment from the anatomical root apex. The real temperature of Buchanan plugger was recorded before insertion into the root canal. The root canal was obturated with continuous wave of condensation technique as described by Buchanan and the root surface temperature was recorded during obturation at $150^{\circ}C,{\;}200^{\circ}C,{\;}250^{\circ}C{\;}and{\;}300^{\circ}C$ temperature settings of System B HeatSource (Model 1005, Analytic technologies, Redmond, WA, USA). After completion of the temperature recording, the dentinal-cementum thickness at each sites was measured. The data were analyzed using one-way ANOVA followed by Scheffe's test and linear regression test. The results were as follows. 1. When the temperature was set at $150^{\circ}C,{\;}200^{\circ}C,{\;}250^{\circ}C{\;}and{\;}300^{\circ}C$ on the digital display of System B HeatSource, the real temperature of the plugger at the 1mm point from the tip revealed $130.82{\pm}2.96^{\circ}C,{\;}158.00{\pm}5.26^{\circ}C,{\;}215.92{\pm}6.91^{\circ}C{\;}and{\;}249.88{\pm}3.65^{\circ}C$ respectively. 2. The position of 8 mm from the anatomical apex showed the highest temperature increase at each temperature settings and it was significantly higher than those of other positions (p<0.0l). The temperature rise was constantly increased toward coronal portion from apex of the root. 3. The maximum temperature increase on the root surface was $2.37{\pm}0.09^{\circ}C{\;}at{\;}150^{\circ}C{\;}setting,{\;}3.11{\pm}0.12^{\circ}C{\;}at{\;}200^{\circ}{\;}setting,{\;}3.93{\pm}0.09^{\circ}C{\;}at{\;}250^{\circ}C{\;}setting{\;}and{\;}5.69{\pm}0.15^{\circ}C{\;}at{\;}300^{\circ}C$ setting respectively. These results suggest that it be relatively kind to the supporting tissues of the root that the root canal is obturated using continuous wave of condensation technique at $150^{\circ}C,{\;}200^{\circ}C,{\;}250^{\circ}C{\;}and{\;}300^{\circ}C$ temperature settings on digital temperature display of System B HeatSource.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.52-52
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• 2008

The positive temperature coefficient of resistivity (PTCR) effect in (1-x)$BaTiO_3$ - $x(Bi_{0.5}K_{0.5})TiO_3$ doped with $Nb_2O_5$ was investigated. $(Bi_{1/2}K_{1/2})TiO_3$ (BKT) is more environment-friendly than $PbTiO_3$ in order to use in PTC thermistors. The incorporation of 1 mol% BKT to $BaTiO_3$ increased the Curie temperature (Tc) to $148^{\circ}C$. Doping of $Nb_2O_5$ to $Ba_{0.99}(Bi_{0.5}K_{0.5})_{0.01}TiO_3$ (BaBKT) ceramic has enhanced its PTCR effects. For the sample containing 0.025 mol% $Nb_2O_5$, it showed good PTCR properties; low resistivity at room temperature (${\rho}_r$) of 30 $\Omega{\cdot}cm$, a high PTCR intensity of approximately $3.3\times10^3$, implying the ratio of maximum resistivity to minimum resistivity (${\rho}_{max}/{\rho}_{min}$) in the measured temperature range, and a large resistivity temperature factor (a) of 13.7%/$^{\circ}C$ along with a high Curie temperature (Tc) of $167^{\circ}C$. In addition, the cooling rate of the samples during the sintering process had an influence on their PTCR behavior. All the samples showed the best ${\rho}_{max}/{\rho}_{min}$ ratio when they have cooled down at a rate of $600^{\circ}C$/min.

• Annals of Clinical Neurophysiology
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• v.13 no.2
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• pp.80-86
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• 2011

Background: A dry-type electrode is an alternative to the conventional wet-type electrode, because it can be applied without any skin preparation, such as a conductive electrolyte. However, because a dry-type electrode without electrolyte has high electrode-to-skin impedance, an impedance-converting amplifier is typically used to minimize the distortion of the bioelectric signal. In this study, we developed an active dry electroencephalography (EEG) electrode using an impedance converter, and compared its performance with a conventional Ag/AgCl EEG electrode. Methods: We developed an active dry electrode with an impedance converter using a chopper-stabilized operational amplifier. Two electrodes, a conventional Ag/AgCl electrode and our active electrode, were used to acquire EEG signals simultaneously, and the performance was tested in terms of (1) the electrode impedance, (2) raw data quality, and (3) the robustness of any artifacts. Results: The contact impedance of the developed electrode was lower than that of the Ag/AgCl electrode ($0.3{\pm}0.1$ vs. $2.7{\pm}0.7\;k{\Omega}$, respectively). The EEG signal and power spectrum were similar for both electrodes. Additionally, our electrode had a lower 60-Hz component than the Ag/AgCl electrode (16.64 vs. 24.33 dB, respectively). The change in potential of the developed electrode with a physical stimulus was lower than for the Ag/AgCl electrode ($58.7{\pm}30.6$ vs. $81.0{\pm}19.1\;{\mu}V$, respectively), and the difference was close to statistical significance (P=0.07). Conclusions: Our electrode can be used to replace Ag/AgCl electrodes, when EEG recording is emergently required, such as in emergency rooms or in intensive care units.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1638-1643
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• 2018

Multi-layer ceramic capacitors as decoupling capacitor were fabricated by dielectric composition with a high dielectric constant. The fabricated decoupling capacitors were embedded in the PCB of the 10G RF transceiver module and evaluated for the characteristics of electrical noise by the level of AC input voltage. In order to further improve the electrical properties of the $BaTiO_3$ based composite, glass frit, MgO, $Y_2O_3$, $Mn_3O$, $V_2O_5$, $BaCO_3$, $SiO_2$, and $Al_2O_3$ were used as additives. The electrical properties of the composites were determined by various amounts of additives and optimum sintering temperature. As a result of the optimized composite, it was possible to obtain a density of $5.77g/cm^3$, a dielectric constant of 1994, and an insulation resistance of $2.91{\times}10^{12}{\Omega}$ at an additive content of 5wt% and a sintering temperature of $1250^{\circ}C$. After forming a $2.5{\mu}m$ green sheet using the doctor blade method, a total of 77 layers were laminated and sintered at $1180^{\circ}C$. A decoupling capacitor with a size of $0.6mm(W){\times}0.3mm(L){\times}0.3mm(T)$ (width, length and thickness, respectively) and a capacitance of 100 nF was embedded using a PCB process for the 10G RF Transceiver modules. In the range of AC input voltage 400mmV @ 500kHz to 2200mV @ 900kHz, the embedded 10G RF Transceiver modules evaluated that it has better electrical performance than the non-embedded modules.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.1
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• pp.7-15
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• 2004

Nitric oxide (NO) system has been implicated in a wide range of physiological functions in the nervous system. However, the role of NO in regulating the neural activity in the gustatory zone of nucleus tractus solitarius (NTS) has not been established. The present study was aimed to investigate the role of NO in the gustatory NTS neurons. Sprague-Dawley rats, weighing about 50 g, were used. Whole cell patch recording and immunohistochemistry were done to determine the electrophysiological characteristics of the rostral gustatory nucleus of the tractus solitaries and distribution of NO synthases (NOS). Neuronal NOS (nNOS) immunoreactivity was strongly detected along the solitary tract extending from rostral to caudal medulla. Resting membrane potentials of NTS neurons were $-49.2{\pm}2\;mV$ and action potential amplitudes were $68.5{\pm}2\;mV$ with a mean duration measured at half amplitude of $1.7{\pm}0.3\;ms$. Input resistance, determined from the response to a 150 ms, -100 pA hyperpolarizing current pulse, was $385{\pm}15\;M{\Omega}$, Superfusion of SNAP or SNP, NO donors, produced either hyperpolarization (68%), depolarization (5%), or no effect (27%). The hyperpolarization was mostly accompanied by a decrease in input resistance. The hyperpolarization caused by SNAP or SNP increased the time to initiate the first action potential, and decreased the number of action potentials elicited by current injection. SNP or SNAP also markedly decreased the number of firing neural discharges of the spontaneous NTS neural activity under zero current. Superfusion of L-NAME, a NOS inhibitor, slightly depolarized the membrane potential and increased the firing rate of NTS neurons induced by current injection. ODQ, a soluble guanylate cyclase inhibitor, ameliorated the SNAP-induced changes in membrane potential, input resistance and firing rates. 8-Br-cGMP, a non-degradable cell-permeable cGMP, hyperpolarized the membrane potential and decreased the number of action potentials. It is suggested that NO in the gustatory NTS has an inhibitory role on the neural activity of NTS through activating soluble guanylate cyclase.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1058-1067
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• 2000

In this study, eel, puffer and snake head fish, which are widely taken and highly valued for processing into baked fish, soup or fish juice were studied by classifying them into wild fish and cultured fish, and evaluated in terms of taste. The samples were gathered in the area including Kimhae, Samchonpo and Haman in Kyungsangnam-do, Kangsu-Gu in Pusan and Bukcheju-Gun in Cheju-do. Proximate compositions, the content of nucleotides and their related compounds, total and free amino acids, organic acids and fatty acids of the fishes were analysed. Generally, as for the compositions, wild fish had a higher crude fat content and a lower moisture content as compared with cultured fish, while there was no great difference between them in terms of crude protein and ash contents. Nucleotides and their related compounds including ATP, ADP, AMP, IMP, HxR, Hx were detected, and the amounts of which were nearly the same with respect to the growth conditions. IMP content was high in all of the samples, while ATP content was extremely low. Total 17 amino acids were detected from the samples, and most of the samples had high contents of glutamic acid, aspartic acid, lysine, leucine, glycine, alanine and arginine, and low contents of cystein, isoleucine and methionine. As for the other amino acids, generally same level of contents were detected for each samples. In cases of eel and snake head fish, the wild fish had higher total amino acid contents in comparison with cultured fish. And the result to the contrary was obtained for the case of puffer. Sample fishes had nearly the same compose distribution of free amino acid though the contents of which were a little different according to the samples. Each sample had high contents of taurine, hydroxyproline, glutamic acid, glycine, cystathionine, ${\beta}-aminoisobutyric$ acid and lysine. Total organic acid contents of cultured fish was higher than that of wild fish. All fishes commonly had high contents of lactic acid, iso-valeric acid, oxalic acid and fumaric acid. High levels of $C_{16:0},\;C_{16:1},\;C_{18:1(cis)},\;C_{18:3},\;and\;C_{22:6}$ were shown in all of the samples and ${\omega}-3$ polyunsaturated fatty acid content of cultured fish was higher than that of wild fish, and as for the essential fatty acid, wild fish has higher content in comparison with cultured fish.

• Korean Journal of Veterinary Research
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• v.43 no.3
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• pp.361-371
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• 2003

The vasorelaxant actions and blood pressure lowering of the ${\alpha}_2$-adrenoceptor agonists (${\alpha}_2$-AAs) clonidine and xylazine were investigated in rat isolated aortic rings and anesthesized rats. Both clonidine and xylazine produced a concentration-dependent inhibition of the sustained contraction induced by norepinephrine (NE), but not by KCl. NE-induced contractions were attenuated partly by nifedipine or verapamil, voltage dependent $Ca^{2+}$ channel blockers. These $Ca^{2+}$ channel blockers-resistant contractions were abolished by clonidine or xylazine. Inhibitory effects of a ${\alpha}_2$-AAs on contractions could be reversed by ryanodine, an intracellular $Ca^{2+}$, transport blocker, and tetrabutylammonium (TBA), a $Ca^{2+}$ activated $K^+$ channel blocker, but not by nifedipine, glibenclamide or removal of extracellular $Ca^{2+}$ and endothelium. Moreover, ${\alpha}_2$-AAs produced relaxation in NE-precontracted isolated intact aortic rings in a concentration-dependent manner, but not in KCl-precontracted rings. The relaxant effects of ${\alpha}_2$-AAs were inhibited by ryanodine and TBA, but not by nifedipine, glibenclamide, N (G)-nitro-L-arginine (L-NNA), N(omega)-nitro-L-arginine methyl ester (L-NAME), aminoguanidine (AG), 2-nitro-4-carboxyphenyl N,N-diphenylcarhurnte (NCDC), lithium sulfate, staurosporine or removal of extracellular $Ca^{2+}$ and endothelium. In vivo, infusion of xylazine elicited significant decrease in anerial blood pressure. This xylazinelowered blood pressure was completely inhibited by the intravenous injection of TBA, but not by the intravenous injection of glibenclamide, L-NNA, L-NAME, AG, nifedipine, lithium sulfate or saponin.. These findings showed that the receptor-mediated and ${\alpha}_2$-adrenoceptor A-stimulated endothelium-independent vasorelaxant effect may be explained by decreasing intracellular $Ca^{2+}$ release and activation of $Ca^{2+}$-activated $K^+$ channels, which may contribute to the hypotensive effects of ${\alpha}_2$-AAs in rats.

• Korean Journal of Materials Research
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• v.20 no.4
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• pp.175-180
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• 2010

Transparent conducting oxide (TCO) films are widely used for optoelectronic applications. Among TCO materials, zinc oxide (ZnO) has been studied extensively for its high optical transmission and electrical conduction. In this study, the effects of $O_2$ plasma pretreatment on the properties of Ga-doped ZnO films (GZO) on polyethylene naphthalate (PEN) substrate were studied. The $O_2$ plasma pretreatment process was used instead of conventional oxide buffer layers. The $O_2$ plasma treatment process has several merits compared with the oxide buffer layer treatment, especially on a mass production scale. In this process, an additional sputtering system for oxide composition is not needed and the plasma treatment process is easily adopted as an in-line process. GZO films were fabricated by RF magnetron sputtering process. To improve surface energy and adhesion between the PEN substrate and the GZO film, the $O_2$ plasma pre-treatment process was used prior to GZO sputtering. As the RF power and the treatment time increased, the contact angle decreased and the RMS surface roughness increased significantly. It is believed that the surface energy and adhesive force of the polymer surfaces increased with the $O_2$ plasma treatment and that the crystallinity and grain size of the GZO films increased. When the RF power was 100W and the treatment time was 120 sec in the $O_2$ plasma pretreatment process, the resistivity of the GZO films on the PEN substrate was $1.05\;{\times}\;10^{-3}{\Omega}-cm$, which is an appropriate range for most optoelectronic applications.