• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.706-709
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• 2003

The antioxidant activities of methanol and dichloromethane/acetone extracts of twenty three seaweeds were tested by using 1,1-Diphenyl-2-picryl-hydrazyl(DPPH) at a $100{\mu}g/ml$ concentrations. The dichloromethane/acetone extracts of three seaweeds(Symphyocladia latiuscula, Gloiopoltis furcata, Sagassum thunbergii), were found to be most effective in DPPH radical scavenging activity. The DPPH radical scavenging effect of these seaweeds was Symphyocladia latiuscula(85.82%), Gloiopoltis furcata(82.83%), Sagassum thunbergii(74.05%) in order. These seaweeds were evaluated using the pyrogallol UV-VIS spectrophotometeric method to generate superoxide anion. Among them, the methanol extracts of six seaweeds were showed weak superoxide dismutase-like activities. The dichloromethane/acetone extracts obtained from Symphyocladia latiuscula was fractionated with $CH_2Cl_2$, n-hexane, 15% aq.MeOH, n-BuOH, $H_2O$. The 15% aq.MeOH soluble fraction exhibiting the strongest antioxidative activities was further purified by C18 column flash chromatography and reversed HPLC. The two active principles of Symphyocladia latiuscula were isolated and characterized as 2,3,6-tribromo-4,5-dihydroxybenzyl alcohol(1), 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether(2).

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.6
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• pp.71-77
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• 2014

In this paper, we investigated the effects of high-energy electron beam irradiation (HEEBI) on the optical transmittance of InGaZnO (IGZO) films grown on transparent Corning glass substrates, with a radio frequency magnetron sputtering technique. The IGZO thin films deposited at low temperature were treated with HEEBI in air at room temperature (RT) with an electron beam energy of 0.8 MeV and doses of $1{\times}10^{14}-1{\times}10^{16}electrons/cm^2$. The optical transmittance of the IGZO films was measured using an ultraviolet visible near-infrared spectrophotometer (UVVIS). The detailed estimation process for separating the transmittance of HEEBI-treated IGZO films from the total transmittance of IGZO films on transparent substrates treated with HEEBI is given in this paper. Based on the experimental results, we concluded that HEEBI with an appropriate dose of $10^{14}electrons/cm^2$ causes a maximum increase in the transparency of IGZO thin films. We also concluded that HEEBI treatment with an appropriate dose shifted the optical band gap ($E_g$) toward the lower energy region from 3.38 to 3.31 eV. This $E_g$ shift suggested that HEEBI in air at RT with an appropriate dose acts like a thermal annealing treatment in vacuum at high temperature.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.236-237
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• 2012

ZnO nanorods were grown on R-plane sapphire substrates with the seed layers annealed at different temperature. The effects of annealing temperature for the seed layers on the properties of the ZnO nanorods were investigated by scanning electron microscopy, X-ray diffraction, UV-visible spectroscopy, and photoluminescence. For the as-prepared seed layers, the ZnO nanorods and the ZnO nanosheets were observed. Only the ZnO nanorods were grown as the annealing temperature was above $700^{\circ}C$. The optical transmittance in the UV region was almost zero while that in the visible region was gradually increased as the annealing temperature increased to $700^{\circ}C$. The optical band gap of the ZnO nanorods was increased as the annealing temperature increased to $700^{\circ}C$. In the visible region, the refractive index was decreased with increasing the wavelength, and the extinction coefficient was decreased as the annealing temperature increased to $700^{\circ}C$. The non-linear exciton radiative life time of the FX emission peak was established by cubic equation. The values of Varshni's empirical equation fitting parameters were ${\alpha}=4{\times}10^{-3}eV/K$, ${\beta}=1{\times}10^4K$, and $E_g(0)=3.335eV$ and the activation energy was found to be about 94.6 meV.

• Journal of Life Science
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• v.26 no.8
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• pp.948-954
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• 2016

We investigated the flavonoid and phenol contents and antioxidant effect of wine by-product extract. Antioxidant effects were measured with 1,1-diphenyl-2-picryhydrazyl (DPPH) and 2.2'-azino-bis(3-ethylbenothiazoline-6-sulfonic acid) diammonium salt radical cation (ABTS+) assays. Cellular reactive oxygen species (ROS) were measured with the dichlorofluorescein-diacetate (DCFH-DA) assay. The flavonoid and phenol contents of the methanol (MeOH) extract were greater than those of the acetone+methylene chloride (A+M) extract. Among fractions, the 85% aqueous methanol (85% aq. MeOH) fraction contained the highest flavonoid contents, while the n-BuOH fraction had more phenol contents. In the DPPH and ABTS assays, the MeOH extract showed a scavenging effect greater than that of the A+M extract (p<0.05). The n-BuOH fraction (0.5 mg/ml concentrations) showed scavenging effects of 72% and 92%, respectively, in the DPPH and ABTS assays (p<0.05). However, the 85% aq. MeOH fraction showed a 90% scavenging effect in the DPPH assay only. In 120 min ROS production assay, all tested fractions dose-dependently decreased cellular ROS production induced by H₂O₂ in comparison with that produced by exposure to the extract-free control. The MeOH extract showed a higher sinhibitory effect on cellular ROS producing than that of the A+M extract at all concentrations tested. Treatment with the n-BuOH fraction (0.1 mg/ml concentrations) inhibited cellular ROS production by 60%. These results indicate that the n-BuOH fraction of wine by-product extract inhibited cellular oxidation and may contain valuable bioactive compounds such as flavonoids and phenols.

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.530-534
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• 2011

The synthesis of dimethyl carbonate by liquid phase oxidative carbonylation of methanol was studied under batch reaction system. Reaction factors such as effect on various metals, anion containing in copper catalyst, temperature, carbon monoxide and oxygen molar ratio and copper content were investigated. In particular $CuCl_2{\cdot}2H_2O$ showed the excellent of the methanol conversion 65.2%, DMC selectivity 96.6% reaction condition under 1.0 g, $150^{\circ}C$, MeOH/CO/$O_2$=0.2/0.215/0.05 (molar ratio). $CuCl_2$ led to corrosion of the reactor. Thus, a new catalyst system using supports was investigated to resolve these corrosion problem. Influence on various supports were examined and copper catalyst supported on zeolite Y showed the most excellent activity on the formation of dimethyl carbonate. The amount of Fe dissolved during the reaction using ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometer) was compared with catalysts, calcined Cu/zeolite Y showed the lower value below 5% than $CuCl_2-2H_2O$.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.4
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• pp.230-235
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• 1993

This study was carried out to investigate the supplying capacity of various forms(Water soluble, exchangeable, and available) of potassium in soils of different site quality by using surface soils from the Japanese cedar(Cryptomeria japonica) forests in Cheju island. Major results can be summerized as follows. Using continuous leaching methods with 0.01N-HCl, accumulated amounts of available potassium from surface soils of site upper and site low were about 0.6me/100g and 0.4me/100g, respectively. The release ratio of available potassium in the first $1{\ell}$ leaching of 0.01N-HCl to the total available potassium leached with $6{\ell}$ of 0.01N-HCl was over 80% for both sites, and this suggester that surface soil of both sites had the weak potassium adsorptivity as the typical volcanic ash soil. The ratio of the exchangeable potassium to the water soluble potassium was 1 : 1 for both sites. The ratio of the exchangeable potassium to the available potassium was 1 : 1 for the site low but the smaller ratio value for the site upper, indicating that the potassium supplying power of the site upper was greater than that of the site low. Available potassium was highly correlated with exchangeable Ca($0.83^{**}$) and Mg($0.84^{**}$).

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.668-672
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• 2003

An antioxidative activity of Portulaca oleracea was tested by in vitro experimental models. The antioxidative activities were determined by evaluation the DPPH radical scavenging activity and by measuring lipid peroxide using 2-thiobarbituric acid (TBA). The crude extract was sequentially partitioned with n-hexane, 15% aq. MeOH, EtOAc, n-BuOH, $H_2O$. Among them, a remarkable antioxidative effect was observed in the fractions of EtOAc and n-BuOH. The DPPH radical scavenging effect $(IC_{50}=17.90{\mu}g/ml)$ of the n-BuOH soluble fraction was comparable with that of natural antioxidant, ${\alpha}-tocopherol(IC_{50}=\;6.99{\mu}g/ml)$ and the inhibitory effect of lipid peroxidation in mouse liver homogenate was similar to that of natural antioxidant, L-ascorbic acid at a concentration of 0.1mg/ml to 5mg/ml. From the BuOH soluble fraction yielded two biophenolic glycosides, 3-hydroxy-1-(2-hydroxyethyl)phenyl-4-O-${\beta}$-D-glucopyranoside(1) and 2-(3,4-dihydroxyphenyl)ethyl-O-${\beta}$-D-glucopyranoside(2) using column chromatography and revered-phase HPLC. In particular, the DPPH radical scavenging activity of 2 was comparable to that tocopherol$(IC_{50}=6.59{\mu}g/ml)$.

• Journal of Applied Biological Chemistry
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• v.57 no.1
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• pp.1-5
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• 2014

The roots of Opuntia humifusa (OHR) were extracted with 80% aqueous MeOH and the concentrated extract was partitioned with EtOAc, n-butanol and $H_2O$, successively. The fractions were tested using DPPH and ABST radical scavenging method. The all fractions showed potent scavenging effects. The scavenging effect of the EtOAc fraction was higher than the other fractions, with $IC_{50}$ values as DPPH; $77.0{\pm}1.38{\mu}g/mL$, ABTS: $26.3{\pm}2.02{\mu}g/mL$. And, we investigated anti-inflammatory activities by examining the effects of the OHR fractions on pro-inflammatory cytokine release in the human mast cells (HMC-1). Treatment with OHR fractions clearly reduced the release of the proinflammatory cytokines tumor necrosis factor-alpha (TNF-${\alpha}$), interleukin (IL)-$1{\beta}$, interleukin (IL)-6 and interleukin (IL)-8) in PMACI-stimulated HMC-1 cells. The results showed the potential of OHR as an excellent antioxidant substance and inhibiting inflammatory mediators. Therefore, OHR may be used as a therapeutic approach to various inflammatory diseases.

• Journal of Life Science
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• v.30 no.2
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• pp.147-155
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• 2020

In this study, the antioxidant and cytotoxic effects and the flavonoid contents of leaf extracts from Stachys sieboldii Miq. and Lycopus lucidus Turcz. were compared. The flavonoid contents of the acetone + methylene chloride (A+M) and methanol (MeOH) extracts of L. lucidus Turcz. leaves were 55.7 and 233.2 mg/g, respectively. In a DPPH assay, A+M and MeOH extracts from L. lucidus Turcz leaves had a greater scavenging effect than those of S. sieboldii Miq. leaves (p<0.05). In an ABTS assay, MeOH extracts from S. sieboldii Miq. and L. lucidus Turcz (0.5 mg/ml concentration) leaves had scavenging effects of 85% and 91%, respectively (p<0.05), suggesting that both of the MeOH extracts had greater scavenging effects than both A+M extracts. In a 120 min ROS production assay, all tested extracts decreased the cellular ROS production induced by H₂O₂ compared to that produced by exposure to the extract-free control. The MeOH extract from L. lucidus Turcz leaves had a greater inhibitory effect on cellular ROS production (p<0.05). Treatment with A+M and MeOH extracts from both S. sieboldii Miq. and L. lucidus Turcz. leaves showed a dose-dependent increased cytotoxicity against the growth of AGS, HT-29 cancer cells, and HT-1080 (p<0.05). Both A+M extracts had a greater inhibitory effect on the growth of all cancer cells than both MeOH extracts. These results suggest that the MeOH extract of L. lucidus Turcz. leaves is effective in scavenging free radicals and inhibiting cellular oxidation, while the A+M extract inhibits proliferation of three types of cancer cell.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.1
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• pp.69-74
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• 1977

This study has been conducted to identify physico-chemical and clay mineralogical characteristics of bentonites produced in Korea for the purpose of finding good quality bentonite for agricultural ure. The results are summarized as follows: 1. Bentonites are mainly composed of montmorillonite developed from tuffs in a lava flow. 2. Chemical properties of bentonites are: pH in $H_2O$(1:1), 7:cation exchange capacity, 60-96me/100g; content of $SiO_2$, 54-72%; ratio of $SiO_2$ to $Al_2O_3$, 4.1-10.0;oven dry loss of $H_2O$ is higher than the ingnition loss of $H_2O$. 3. The x-ray diffrection patterns of powder bentonites show peaks at $14-15{\AA}$, $4.4{\AA}$, and $2.5{\AA}$, and that of swellen one show $17{\AA}$ when treated with ethylene glycol. 4. Distribution areas of the good quality bentonites were (1) Dogu-Dong, Donghae-Myeon, Yeonil-Gun, Gyeongsangbug-Do (2) Hamyeon-Ri, Yangnam-Myeon, Weolseong-Gun, Gyeongsanbug-Do. (3) Joam-Ri, Gangdong-Myeon, Weolseong-Gun, Gyeongsangbug-Do. (4) Sanha-Ri, Gangdong-Myeon, Ulju-Gun, Gyeongsangnam-Do. (5) Sinhyeon-Ri, Gangdong-Myeon, Ulju-Gun, Gyeongsangnam-Do. (6) Yonghang-Ri, Pyeongchang-Myeon, Pyeongchang-Gun, Gangweon-Do.