• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.3
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• pp.261-269
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• 2009

To evaluate the effect of antioxidant on the cytotoxicity induced by oxidative stress of reactive oxygen species (ROS) in cultured human skin melanocytes, colorimeric assay of XTT and tyrosinase activity assay were adopted after human skin melanocytes were preincubated for 2 hours in the media containing various concentrations of superoxide dismutase (SOD) before the treatment of hydrogen peroxide. Light microscopic study was carried out in same cultures. The results of this study were as follows 1. Cell viability of human skin melanocytes was significantly decreased by 30 and $40{\mu}M$ of hydrogen peroxide($H_2O_2$), respectively. 2. XTT50 was determined at $30{\mu}M$ after human skin melanocytes were treated with $10{\sim}40{\mu}M$ of hydrogen peroxide for 6 hours. 3. The cell viability of cultured human skin melanocytes pretreated with SOD was increased than that of cultured human skin melanocytes treated with $H_2O_2$ dose-dependently. 4. In tyrosinase activity of human skin melanocytes, the cell treated with SOD showed brown stain compared with $H_2O_2$ treated cells, dark stain. 5. In light microscopy, cultured human skin melanocytes exposed to $H_2O_2$ showed morphological changes such as the decreased cell number and cytoplasmic processes, compared with control. 6. In light microscopy, cultured human skin melanocytes pretreated with SOD showed the increase of cell number and cytoplasmic processes compared with $H_2O_2-treated$ group. From these results, it is suggested that oxidative stress of ROS such as $H_2O_2$ has cytotoxicity by showing the decreased cell viability, the increased tyrosinase activity and mophological changes of the decreased cell number and cytoplasmic processes. While, antioxidant like SOD was effective in the prevention of oxidative stress-mediated cytotoxicity by the increased cell viability, decreased tyrosinase activity and the protection of degenerative morphological changes in cultured human skin melanocytes.

• Journal of the Korean Magnetics Society
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• v.11 no.3
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• pp.129-133
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• 2001

In this paper, we studied structural and magnetic properties of Ba-ferrite thin film deposited on Si(100) substrate with TiO$_2$ underlayer. Ba-ferrite thin films with TiO$_2$ underlayer were deposited by reactive RF/DC magnetron sputtering system at room temperature. TiO$_2$ underlayer was reactive sputtered with $O_2$. After deposition, the thin films were annealed at vatious temperatures to get the crystallized sample. Underlayer was used to prevent interdiffusion from Ba-ferrite thin film to substrate. The growth of Ba-ferrite thin films was influenced by TiO$_2$ underlayer. Easy magnetization direction is in-plane. From these results the Ba-ferrite film with TiO$_2$ underlayer can be used as longitudinal recording media.

• Journal of the Korean Magnetics Society
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• v.11 no.3
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• pp.122-128
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• 2001

In this paper, we studied structural and magnetic properties of Ba-ferrite thin film deposited on Si(100) substrate with various underlayers. Ba-ferrite thin films with various underlayers were deposited by reactive RF/DC magnetron sputtering system at room temperature. various underlayers was reactive sputtered with O$_2$. After deposition, the thin films were annealed at 850 $^{\circ}C$ to get the crystallized sample. Underlayers were used to prevent interdiffusion from Ba-ferrite thin film to substrate. The growth of Ba-ferrite thin films was influenced by underlayers. Easy magnetization direction is in-plane. From these results the Ba-ferrite film with various underlayers can be used as longitudinal recording media.

• Clean Technology
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• v.14 no.3
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• pp.218-223
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• 2008

Decomposition of reactive organic compound dispersed in microemulsion media by hydroxide ions and proton ions generated during electrolysis was tried and the half-lifes for decomposition were compared. Absorbance of p-nitrophenoxide produced from the decomposition of p-nitrophenylacetate (PNPA) was followed to find the rate of decomposition. The applied voltage, temperature, and the amount of substrate were changed to see the effects on the decomposition rate. The advantages of electrolysis in microemulsion system were the high solubilizing capacity of substrate, easy control of decomposition rate, low operation cost, no need for any addition of chemicals, and no byproducts. The mechanism of decomposition and the application to water purification were discussed.

• Korean Journal of Microbiology
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• v.32 no.2
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• pp.132-138
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• 1994

L-Ascorbic acid-producing enzyme in Neurospora crassa was found to exist in mitochondria and the activity of this enzyme was increased by the addition of D-fluconno-${\gamma}$-lactone or L-gulono-${\gamma}$-lactone in the media. L-Ascorbic acid-producin enzyme in N. crassa has been purified with ammonium sulfate precipitation. DEAE Sepharose CL-6B ion exchange chromatography. Sephacryl S-200 gel filtration chromatography and Reactive yellow 3-agarose dye affinity column chromatography. The specific activity of this enzyme was increased to 239.6 fold and the yield was 2.1%. The molecular weight of the native enzyme was 150.000 dalton when it was estimated with Sephacryl S-200 gel filtration chromatography. Its molecular weight appeared as 75.000 dalton by SDS-polyacrylamide gel electrophoresis. which suggested that this enzyme was consisted with two identical subunits. The optimal pH for this enzyme was 9.0 and the $K_m$ value for D-galactono-${\gamma}$-lactone was 0.073 mM.

• Journal of Life Science
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• v.24 no.5
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• pp.549-557
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• 2014

This study examined the quality characteristics of fermented black garlic (BG) with probiotics. Nine strains of probiotics were tested in media containing 20% BG. Four of the strains grew well in the BG media: Lactobacillus rhamnosus, L. paracasei subsp. paracasei, L. casei, and L. plantarum. These four strains were used to make 10, 20, and 30% BG fermented product, respectively. The number of viable cells, pH, acidity, S-allyl cysteine (SAC) concentration, and nitric oxide (NO) and reactive nitrogen species (ROS) generation in Raw 264.7 macrophage cells were measured. L. plantarum showed the best growth of all the strains in the BG media. The pH of all the samples decreased during fermentation, and the acidity increased acidity. However, they did not differ significantly from the pH and acidity of the control. In all four strains, the SAC content did not differ before and after fermentation. However, the SAC content increased, depending on the BG concentration. NO production was inhibited in the L. rhamnosus inoculation strain compared to the other strains. ROS generation was also significantly inhibited in the L. plantarum inoculation strain compared to the other strains. The results show that the characteristics of BG fermentation products are determined by the fermentation strain. Therefore, fermentation products with particular characteristics can be produced using a single strain or mixed strains.

• Journal of Environmental Impact Assessment
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• v.30 no.1
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• pp.35-48
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• 2021

In this study, the assessment of field applicability of in-situ remediation of nitrate-contaminated groundwater located in Yesan-gun was performed. Zero-valent iron/bio composite media injected PRB (Permeable Reactive Barrier) and monitoring well were installed in the contaminated groundwater site and monitored main remediation indicators during the PRB operation. Nitrate, nitrite, ammonia, Fe ion, TOC, and turbidity were analyzed and the diversity and population of microorganism in the PRB installed site were investigated for the verification of effect of injected PRB. In the study site where is an agricultural area, a river flows from west to east that forms a river boundary and the southern area has an impermeable sector. It was found that nitrate flows into the river, which is similar as groundwater flow. Simulation result for the fate of nitrate in groundwater showed steady state of nitrate arrived after 3~5 years passed. However, it is just to consider current conditions with no additional input of contaminant source, if additional input of contaminant source occurs contamination dispersion and time for steady state are expected to be increased. The monitoring results showed that Fe ion, TOC and turbidity in groundwater were not clearly changed in concentration after PRB installation, which indicates adaptability of the injected PRB for remediation of groundwater with no additional harmful effect to water quality. The concentration of nitrate maintained less than 5mg/L until 42 days after PRB installation and recovered its initial concentration after 84 days passed and showed termination of reactivity of injected zero-valent iron/bio composite media for removal nitrate. Nitrite and ammonia ions found after installation of PRB indicates reductive removal of nitrate. And the outstanding increase of microorganism diversity and population of Betaproteobacteria Class which includes denitrification microorganism explains biologically reductive removal of nitrate in injected PRB.

• Reproductive and Developmental Biology
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• v.38 no.4
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• pp.143-146
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• 2014

Antioxidants, as reactive oxygen species scavengers, are one of the beneficial additives in serum-free defined culture medium. In this study, three separate experiments were performed to determine the effects of 3-hyroxyflavone added to the culture medium on the developmental competence of follicular bovine oocytes during in vitro maturation (IVM) and/or in vitro culture (IVC). The rate of blastocyst developed from oocytes cultured in IVM medium with 3-hyroxyflavone was significantly higher than that from control oocytes (39.0% vs. 26.3%, p<0.001), respectively. However, oocytes cultured in the medium with addition of 3-hyroxyflavone only at IVC period did not show significance in the blastocyst development when compared with control. When 3-hyroxyflavone was added to both IVM and IVC media, the rate of blastocyst formation was even significantly lower (21.1%) than control (26.5%; p<0.05). The present findings suggested that antioxidative activity of 3-hydroxyflavone added to only IVM medium beneficially affected the developmental competence of follicular bovine.

• Journal of Fashion Business
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• v.13 no.1
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• pp.115-124
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• 2009

Chitosan and CA/BTCA were employed in order to induce crosslinking in the fiber for the improvement of wrinkle recovery of the cotton fabrics and the endowment of anti-microbial functions to the fabric. The treated fabrics were dyed by using reactive dyestuff and their dyeing behaviors were investigated. As a result, the fabric treated with chitosan only exhibited more dye-uptake amount than the untreated fabric, and the treated and untreated fabrics together showed excellent light-fastness and wash-fastness. In the cases that CA or BTCA was added to the chitosan, the CA-treated showed better dye-uptake and dyeing properties as light-fastness than the BTCA-treated. In conclusion, it is possible to maintain the dye-uptake level at reduced treatment cost when the CA is employed as a substitute cross-linking agent for BTCA.

• Biomedical Science Letters
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• v.14 no.1
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• pp.33-38
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• 2008

In order to examine oxidative stress of reactive oxygen species and the antioxidant effect of Citri Reticulatae Pericarpium (CRP) extract, human skin melanoma cells were treated with various concentrations of hydrogen peroxide ($H_2O_2$). Antioxidant effect of CRP extract on $H_2O_2$-induced cytotoxicity, cell viability, DPPH-radical scavenging activity and superoxide dismutase (SOD)-like activity. In this study, $H_2O_2$ decreased cell viability of cultured human skin melanoma cells in dose- and time-dependent manners, and then, midcytotoxicity value (MCV) was determined at $60\;{\mu}M$ after human skin melanoma cells were cultured for 5 hours in the media containing $20{\sim}60\;{\mu}M$ of $H_2O_2$, respectively. The $H_2O_2$ was on cultured human skin melanoma cells because MCV of $H_2O_2$ was lower than $100\;{\mu}M$. In the antioxidant effect of CRP extract, CRP extract increased cell viability DPPH-radical scavenging activity and SOD-like activity. From these results, it is suggested that $H_2O_2$ was very toxic on cultured human skin melanoma cells. And also, CRP extract has the antioxidant effect on $H_2O_2$-induced cytotoxicity.