• Preventive Nutrition and Food Science
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• v.5 no.2
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• pp.114-118
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• 2000

The inhibitory effects of doenjang extracts and linoleic acid(LA) which was identified as one of the active compounds in doenjang on the growth of human cancer cells were studied, comparing to the actions on normal cells. Methanol extract and hexane fraction from doenjang exhibited the strong growth inhibitory effect on HT-29 human colon carcinoma cells. Inhibitory effects of chloroform, ethyl acetate, butanol and aqueous fractions on the cancer cells were observed, moderately or weakly. When cell counts of SNU-C$_1$human colon carcinoma cells were determined daily for 6 days, the inhibitory effect of hexane fraction on this cell line was higher than that of the methanol extract from doenjang. LA completely suppressed the growth of SNU-C$_1$cells after 4 days, while conjugated linoleic acid(CLA) resulted in 98% inhibition after 6 days. With the addition of LA and other free fatty acids such as stearic acid, oleic acid, linolenic acid and ${\gamma}$-linolenic acid (${\gamma}$-LnA) to the culture system, the growth of HT-29 cells and SNU-C$_1$cells was greatly suppressed after 6 days. Inhibitory effects of LA ${\gamma}$-LnA on the growth of these cells were stronger than other fatty acids. On the growth of AZ-521 human gastric carcinoma cells, LA and CLA completely cuppressed the growth of the cells after 4 days and 3 days, respectively. At the level of 0.001%~0.01% of LA, there was no cytotoxic effect on normal rat kidney cells and normal intestine human cells. These results showed that LA, a major active compound of doenjang, had strong inhibitory effects on the growth of human cancer cells without damaging normal cells.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.6
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• pp.528-533
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• 2019

We investigated the growth of $(Al_xGa_{1-x})_2O_3$ thin films on c-plane sapphire substrates that were grown by mist chemical vapor deposition (mist CVD). The precursor solution was prepared by mixing and dissolving source materials such as gallium acetylacetonate and aluminum acetylacetonate in deionized water. The [Al]/[Ga] mixing ratio (MR) of the precursor solution was adjusted in the range of 0~4.0. The Al contents of $(Al_xGa_{1-x})_2O_3$ thin films were increased from 8 to 13% with the increase of the MR of Al. As a result, the optical bandgap of the grown thin films changed from 5.18 to 5.38 eV. Therefore, it was determined that the optical bandgap of grown $(Al_xGa_{1-x})_2O_3$ thin films could be effectively engineered by controlling Al content.

• Advances in environmental research
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• v.3 no.2
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• pp.107-116
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• 2014

This study aimed to synthesize dispersed and reactive nanoscale zero-valent iron (nZVI) with poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA), nontoxic and biodegradable stabilizer. The nZVI used for the experiments was prepared by reduction of ferric solution in the presence of PVP/VA with specific weight ratios to iron contents. Colloidal stability was investigated based on the rate of sedimentation, hydrodynamic radius and zeta potential measurement. The characteristic time, which demonstrated dispersivity of particles resisting aggregation, increased from 21.2 min (bare nZVI) to 97.8 min with increasing amount of PVP/VA (the ratios of 2). For the most stable nZVI coated by PVP/VA, its reactivity was examined by nitrate reduction in a closed batch system. The pseudo-first-order kinetic rate constants for the nitrate reduction by the nanoparticles with PVP/VA ratios of 0 and 2 were 0.1633 and $0.1395min^{-1}$ respectively. A nitrogen mass balance, established by quantitative analysis of aqueous nitrogen species, showed that the addition of PVP/VA to nZVI can change the reduction capacity of the nanoparticles.

• Journal of the Korean Magnetics Society
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• v.4 no.1
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• pp.62-68
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• 1994

Water-based magnetic fluids containing synthesized ultrafine magnetite were successfully prepared with $C_{18}$ fatty acid such as oleic acid, linoleic acid and stearic acid. Oleic acid was needed the amount of $3.0{\times}10^{-2}$ mol per 20 g magnetite to stabilize the magnetite $d\;=\;113\;\AA$ particles. From pH 8.0 to pH 11.0, stable aqueous-based fluids could be obtained. The aggregated powder after drying the water-based magnetic fluid was also successfully re-dispersed in dilute $NH_{4}OH$ solution and in kerosene. The pH levels of the magnetic fluid using oleic acid system could be predicted by the pH values obtained by calculation of therrrodynamic data.

• Journal of Environmental Science International
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• v.28 no.2
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• pp.183-189
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• 2019

Curcumin ($C_{21}H_{20}O_6$) is a hydrophobic polyphenol found in turmeric. Although curcumin has been used as a natural medicine, its major limitation is related to poor absorption from the gut. Therefore, we developed a method for preparation of Curcumin Nanospheres (CN) to improve the aqueous-phase solubility of curcumin and investigate the functional role of CN in promoting feed efficiency and odor reduction in mice. CN showed inhibitory effects on actate dehydrogenase (LDH) cytotoxicity induced by ecotoxic substance toluene in gut epithelial HCT116 cells. In addition, the weights of internal organs (liver, heart, kidneys, and spleen) and the levels of serum Glutamate Oxaloacetate Transaminase (GOT), Glutamate Pyruvate Transaminase (GPT), and LDH did not show significant differences between mice administered oral CN for two weeks and compared to the control group. Interestingly, CN not only reduced hydrogen sulfide ($H_2S$) and ammonia ($NH_3$) levels and fecal odor, but also improved feed efficiency in mice. These results demonstrate that oral nano-delivery of anti-ecotoxicological CN is a functional system to deliver curcumin to the gut to improve feed efficiency and reduce fecal odor in mice.

• Journal of Convergence for Information Technology
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• v.9 no.9
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• pp.245-251
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• 2019

This study was conducted to investigate the anti-oxidative, anti-oxidative and tyrosinase inhibitory effects of MeOH 80% extract and hexane, chloroform, ethyl acetate, butanol and aqueous fraction on three kinds of compositae plants in Korea. In the antimicrobial effect, the extract and chloroform fraction of Eclipta prostrata and hexane fraction of Carpesium abrotanoides L. and chloroform fraction of Siegesbeckia glabrescens exhibited significant inhibition. The antioxidant activity of ethyl acetate and butanol fractions was more than 90% in all three plants. In case of tyrosinase activity, showed a potent inhibition ethlyacetate fraction of Siegesbeckia glabrescens and Carpesium abrotanoides L, which were higher than control group. In MeOH 80% extracts, there was not found to have antimicrobial, anti-oxidant and tyrosinase inhibitory activity, however there was ethylacetate fraction of Siegesbeckia glabrescens to show effectss commonly in the three assay system.

• Korean Journal of Pharmacognosy
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• v.50 no.1
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• pp.65-71
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• 2019

One of the oriental medicine prescriptions, Sagunja-tang consists of four herbal medicines (Ginseng Radix, Poria Sclerotium, Atractylodis Rhizoma Alba, and Glycyrrhiziae Radix et Rhizoma) and has been used as a medicine to enhance tonify the function of spleen and stomach in Korea. In this study, we conducted simultaneous analysis of the 9 marker components, liquiritin apioside, liquiritin, ginsenoside Rg1, liquiritigenin, ginsenoside Rb1, glycyrrhizin, atractylenolide III, atractylenolide II, and atractylenolide I in Sagunja-tang using a liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS/MS). Marker compounds were separated on a Waters Acquity UPLC BEH $C_{18}$ analytical column ($2.1{\times}100mm$, 1.7 mm) and the column was maintained at $45^{\circ}C$. The mobile phase consists of 0.1% (v/v) aqueous formic acid and acetonitrile with gradient condition. The LC-MS analysis was performed using a Waters ACQUITY TQD LC-MS/MS system with multiple reaction monitoring (MRM) method in the positive and negative modes. The calibration curves of the nine marker components showed good linearity with coefficient of determination ${\geq}0.9984$ within tested range. The limits of detection and limits of quantification values were 0.27-2.42 ng/mL and 0.81-7.27 ng/mL, respectively. The concentrations of tested 9 analytes in the lyophilized Sagunja-tang sample using the established LC-ESI-MS/MS MRM method were detected up to 16.593 mg/g. These results can be useful as a basic data for the quality control of an oriental medicine prescriptions.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.224-229
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• 2011

Adsorption characteristics of erythrosine dye onto the activated carbon has been investigated in a batch system with respect to initial concentration, contact time and temperature. Kinetic studies of the adsorption of erythrosine were carried out at 298 K, using aqueous solutions with 100, 250 and 500 mg/L concentration of erythrosine. The adsorption process followed a pseuo second order model, and the adsorption rate constant (k2) decreased with increasing the initial concentration of erythrosine. The equilibrium process can be well discribed by Freundlich isotherm in the temperature range from 298 to 318 K. Free energy of adsorption (${\Delta}G^o$), enthalpy (${\Delta}H^o$), and entropy (${\Delta}S^o$) change were calculated to predict the nature the adsorption. The estimated values for ${\Delta}G^o$ were -3.72~-9.62 kJ/mol over the activated carbon at 250 mg/L, indicated toward a spontaneous process. The positve value for ${\Delta}H^o$ indicates that the adsorption of erythrosine dye on activated carbon is an endothermic process.

• Korean Journal of Materials Research
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• v.32 no.9
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• pp.369-378
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• 2022

The recycling of solid waste materials to fabricate carbon-based electrode materials is of great interest for low-cost green supercapacitors. In this study, porous carbon foam (PCF) was prepared from waste floral foam (WFF) as an electrode material for supercapacitors. WFF was directly carbonized at various temperatures of 600, 800, and 1,000 ℃ under an inert atmosphere. The WFF-derived PCF (C-WFF) was found to have a specific surface area of 458.99 m²/g with multi-modal pore structures. The supercapacitive behavior of the prepared C-WFF was evaluated using a three-electrode system in a 6 M KOH aqueous electrolyte. As a result, the prepared C-WFF as an active material showed a high specific capacitance of 206 F/g at 1 A/g, a rate capability of 36.4 % at 20 A/g, a specific power density of 2,500 W/kg at an energy density of 2.68 Wh/kg, and a cycle stability of 99.96 % at 20 A/g after 10,000 cycles. These results indicate that the C-WFF prepared from WFF could be a promising candidate as an electrode material for high-performance green supercapacitors.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.2
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• pp.132-140
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• 2023

In this study, rotary magnet holder (RMH) was manufactured to analyze the ion transport effect according to the rotating magnetic field for the hydrogen production efficiency by alkaline water electrolyte. In the experiment, the voltage signal according to the magnet arrangement inside the RMH, the rotation speed, and the rotation time was measured using the voltage measurement module. As a result of the voltage signal measurement experiment, the average potential difference increased as the rotation speed of the RMH increased. Through the results of the voltage signal measurement experiment, the most efficient magnet arrangement (case 2) was applied to the RMH to conduct a water electrolysis experiment. A 20% NaOH aqueous solution was filled in the electrolytic cell, and a direct current 2 V constant voltage was applied to measure the current value according to the RMH rotation to compare the hydrogen generation amount. When rotating at 100 RPM, the hydrogen production efficiency increased by 8.06% compared to when not rotating. Considering the area exceeding +25 mA, which was not measured at the beginning of the experiment, an increase in hydrogen production of about 10% or more can be expected.