• Journal of Life Science
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• v.30 no.8
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• pp.688-694
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• 2020

In a previous study, the total phenolic content in ethanol extracts of medicinal plants that naturally grow on Jeju Island were analyzed with the extracts of Raphiolepsis indica leaf found to have the highest. The current study was carried out to evaluate the total flavonoid content, radical-scavenging activity, and the protective effect of R. indica extracts and solvent fractions on oxidative stress in HaCaT keratinocytes. More specifically, total flavonoid content and 2-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical-scavenging activity were measured to assess anti-oxidative activity, and protective effects against hydrogen peroxide (H₂O₂) were determined by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide assay on the HaCaT cells. Of the various fractions analyzed, the ethyl acetate extract of R. indica showed the highest total flavonoid content (149.13 mg/g extracts) and the lowest remaining ABTS. In addition, the ethyl acetate fraction was significantly more resistant against H₂O₂ than the negative control. Our results therefore suggest that an ethyl acetate fraction of R. indica protects HaCaT cells against oxidative stress and could prove useful for developing functional cosmetic materials.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.08a
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• pp.98-102
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• 2003

$Ba_2NaNb_5O_{15}$, hereafter BNN, thin films are attractive candidates for nonvolatile memory and electro-optic devices. In the present work, thin films that have different contents of Ba, Na and Nb have been prepared by H-MOD technique on silicon and Pt substrates. XRD and SEM were used to investigate the phase evolution behavior and the microstructure of the films. It was found that the films of about 450nm thick were crack-free and uniform in microstructure. Nb content strongly influenced the phase formation of the films, where low temperature phase was always formed at the stoichiometric BNN composition. However, the amount of low temperature phase decreased with the increase of excess Nb content, and the single phase (orthorhombic tungsten bronze structure) BNN thin film was obtained at the temperature as low as $750^{\circ}C$ for samples with excess niobium. From this study, the sub-solidus phase diagram below $850^{\circ}C$ for $BaO-Na_2O-Nb_2O_5$ ternary system is proposed.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.4
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• pp.5-11
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• 2023

This study was conducted to improve energy efficiency and problems such as clumping and fouling in the glue zone that occur in the moisture content range of 40 to 60% when sewage dehydration residue is directly fed into the dryer. The temperature of the hot air is low at 270~300℃, and the paddle-type flotation method and dehydrated residue are applied to the circulated heat storage media to increase the contact area with the hot air, thereby reducing energy recovery and gas emissions. The water content of the dried residue is 2.7. ~7 .5%, the heat of evaporation of moisture was 608.0~690.6 kcal/kg·H₂O, which confirmed an energy saving effect of about 8.8% compared to the heat of evaporation of moisture of 714.5 kcal/kg·H₂O when no heat storage media was used.

• Nuclear Engineering and Technology
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• v.53 no.4
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• pp.1323-1330
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• 2021

This work reported the radiation shielding characteristic of the bismuth titanium vanadium sodium tellurite glass system. The density of the specially-developed glass samples was increased from 2.21 to 4.01 g/cm³ with the addition of Bi₂O₃, despite the fact the molar volume is decease within 85.43-54.79 cm³/mol. The WinXcom program was used to approximate the effect of Bi₂O₃ on the gamma radiation shielding parameters of bismuth titanium vanadium sodium tellurite glasses. The ㎛ values decrease with the increase of Bi₂O₃ concentration. The computed data shows that the glass sample with 20 mol.% of Bi₂O₃ content has the greatest radiation attenuation performance in comparison to other selected glasses. The Bi₂O₃-TiO₂-V₂O₅-Na₂O-TeO₂ glass system shows excellent neutron shielding material with high long-term light transmittance and discharge resistance and could be potentially used as transparent radiation-resistant shielding glass applications.

• Korean Journal of Materials Research
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• v.24 no.1
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• pp.43-47
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• 2014

NiO-doped hibonite pigments were synthesized by the solid state method to get stabilized blue color pigment in both oxidation and reduction atmospheres. Optimum substitution condition with NiO for hibonite blue pigment was investigated. Experimental results were comparable to those of previous cobalt-minimization studies performed with other phosphate- or oxide-based cobalt-containing ceramic pigments (having olivine ($Co_2SiO_4$), spinel ($CoAl_2O_4$), or with co-doped willemite ($(Co,Zn)_2SiO_4$) structures). Composition was designed varying the NiO molar ratio increasing with $SnO_2$. The optimum substitution content is 0.93 mole NiO with 0.75mole $SnO_2$. The characteristics of the synthesized pigment were analyzed by XRD, Raman spectroscopy, SEM, and UV-vis. Synthesized pigment was applied to a lime-barium glaze with 10 wt% each and fired at an oxidation atmosphere of $1250^{\circ}C/1h$ and a reducing atmosphere $1240^{\circ}C/1h$. Blue color was obtained with $L^*a^*b^*$ values at 43.39, -6.78, -18.20 under a reducing atmosphere and 41.66, -6.36, -14.7 under and oxidation atmosphere, respectively.

• BMB Reports
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• v.37 no.5
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• pp.586-596
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• 2004

The folding of ervatamin C was investigated in the presence of various fluorinated and non-fluorinated organic solvents. The differences in the unfolding of the protein in the presence of various organic solvents and the stabilities of O-states were interpreted. At pH 2.0, non-fluorinated alkyl alcohols induced a switch from the native $\alpha$-helix to a $\beta$-sheet, contrary to the $\beta$-sheet to $\alpha$-helix conversion observed for many proteins. The magnitude of ellipticity at 215 nm, used as a measure of $\beta$-content, was found to be dependent on the concentration of the alcohol. Under similar conditions of pH, fluorinated alcohol enhanced the intrinsic a-helicity of the protein molecule, whereas the addition of acetonitrile reduced the helical content. Ervatamin C exhibited high stability towards GuHCl induced unfolding in different O-states. Whereas the thermal unfolding of O-states was non-cooperative, contrary to the cooperativity seen in the absence of the organic solvents under similar conditions. Moreover, the differential scanning calorimetry endotherms of the protein acquired at pH 2.0 were deconvoluted into two distinct peaks, suggesting two cooperative transitions. With increase in pH, the shape of the thermogram changed markedly to exhibit a major and a minor transition. The appearance of two distinct peaks in the DSC together with the non-cooperative thermal transition of the protein in O-states indicates that the molecular structure of ervatamin C consists of two domains with different stabilities.

• Korean Journal of Materials Research
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• v.14 no.8
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• pp.547-551
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• 2004

The sulfidation behaviour of Fe-XAl-0.3Y(X=5, 10, 14, 25 $wt.\%$) alloys was investigated at 1123 K in $H_2/H_{2}S$ gas atmosphere for $1\sim24$ hrs using SEM/EDX, XRD and EPMA. The weight changes of Fe-XAl-0.3Y alloys followed the parabolic rate law, Sulfidation rates of iron aluminide alloys with high Al content were one-twentieth lower than that of 5Al alloys. This is due to the formation of protective $Al_{2}O_3$ oxides on the surface of 10Al, 14Al and 25Al alloys. By calculating partial pressure of impurity oxygen contained $H_2/H_{2}S$ gas, the $Al_{2}O_3$ oxides formation could be explained using Fe-Al-S-O thermodynamic stability diagram. The sulfidation product scales of the 5Al alloy showed that thick iron sulfide scale(FeS) containing porosities formed during early stages of sulfidation. With continued sulfidation, aluminum sulfide was formed at the alloy/scale interface.

• The Journal of Internal Korean Medicine
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• v.19 no.1
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• pp.442-451
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• 1998

This study was carried out to examine mechanisms by which Holotrichia (HTC) produces protective effect against renal cell injury. HTC extraction (5%) prevented $H_2O_2(50mM)$-induced LDH release and lipid peroxidation in renal cortical slices. When slices were treated with 5% HTC extraction, cellular glutathione content and the superoxide dismutase activity were not altered in control and $H_2O_2$-treated tissues. When slices were treated with 50 mM $H_2O_2$, the catalase activity was significantly inhibited, which was completely restored by addition of 5% HTC. Treatment of slices with 5% HTC extraction increased the glutation peroxidase activity in $H_2O_2$-treated tissues. These results suggest that HTC prevents oxidant-induced cell injury and lipid peroxidation by increasing the activities of catalase and glutathione peroxidase in renal cortical slices.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.11a
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• pp.119-120
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• 2003

The experiments were conducted to investigate the effects of supplementary feather meal(FM) and its digest on the taurine content and performance of laying hens. Feeding trial was conducted with 810 78-wk-old ISA-Brown layers for 5wk. The experiment consisted of nine dietary treatments ； T1 ; control(basal diet), T2；Tl + feather meal(FM) 6 ％ diet, T3；T2 + pyridoxin(21 mg/kg) supplemented diet, T4； T1 + H$_2$O$_2$treated FM 6%, T5； T4 + pyridoxin(21 mg/kg) supplemented diet, T6； T1 + cystine(0.25 ％) supplemented diet, T7； T6 + pyridoxin(21 mg/kg) supplemented diet, T8； T1 + synthetic taurine supplemented(0.25％) diet, T9； T1 + synthetic taurine supplemented(0.5 ％) diet. Diets were formulated to be iso-caloric and to meet NRC(1994) requirements of essential nutriente. Birds in treatments T3 showed significantly higher(P＜0.01) egg production, feed intake, feed conversion ratio, egg weight, haugh unit and eggshell strength than those fed other treatments. Supplementation of FM. H$_2$O$_2$treated FM and cystine with or without pyridoxin did not significantly affected taurine content of egg yolk. Only synthetic taurine supplemented diets(T8 and T9) linearly increased(P＜0.01) taurine content of egg yolk.

• Korean Journal of Food Science and Technology
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• v.21 no.2
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• pp.269-275
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• 1989

The study was conducted to compare the components such as proximate composition, total dietary fiber(TDF) content, acid detergent fiber(ADF) content, lignin, water binding capacity(WBC), amino acid composition and lipid components from brown Job's tears, dehulled Job's tears, brown Yeomjoo and bran of Job's tears. The results from this study are summerized as follows: Total dietary fiber(TDF) content of Job's tears, brown Job's tears, brown Yeomjoo and bran of Job's tears were 2.70%, 3.86%, 4.33% and 13.3% each. Water-binding capacity(WBC) of TDF and ADF were $2.63{\pm}0.02g\;H_2O/g$ TDF and $5.89{\pm}0.15g\;H_2O/g$ ADF each. In amono acids composition of samples, glutamic acid content was the highest and the next was leucine. Chemical score of leucine in dehulled Job's tears was very high(189), in contrast lysine was very low$(22{\sim}23)$ So lysine was a first limitting amino acid in Job's tears and Yeomjoo. Neutral lipid contents were 90.89%-96.55%, glycolipid contents were 2.35%-7.48% and phospholipid contents were very low. The major fatty acids of lipid fractions were palmitic acid. oleic acid and linoleic acid.