• Journal of Korean Society on Water Environment
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• 제24권3호
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• pp.328-332
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• 2008

This research was about T-N removal efficiency of oxic reactor in which fixed media submerged from Membrane BNR(An+Ax+Ox) process. This experiment was implemented by using fixed media and changing DO concentration in the oxic reactor. Nitrification efficiencies of all modes were more than 98%. When no media was in the oxic reactor, T-N removal efficiency was only 47.4%, while it were shown from 60.3% to 67.4% with packed media, which indicated improved efficiency of 27~42%. The removal efficiencies of TCOD and BOD were more than 89%, 98% respectively, which could satisfy the guideline of advanced sewage reclamation by Department of Environment. When DO concentration in the packed oxic-media tank was 0.5~1.0 mg/L, T-N removal efficiency was low, which resulted from insufficient nitrification in the oxic reactor. Therefore, DO concentration of bulk solution needs to be kept more than 1.0 mg/L to induce higher nitrification efficiency in the reactor in which media was submerged. Also, the selection of DO concentration is important to prevent media from being clogged.

• Macromolecular Research
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• 제12권2호
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• pp.213-218
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• 2004

We have performed dispersion polymerization of acrylamide in tert-butyl alcohol/water mixture-using hydroxypropyl cellulose and ammonium persulfate as the stabilizer and the initiator, respectively - to study the effects that the concentration of monomer, initiator, and stabilizer, the tert-butyl alcohol/water ratios as polymerization media, and the reaction temperature have on, among other things, the polymerization kinetics, particle sizes, and molecular weights. The polymerization rate increased upon increasing the concentration of the monomer, initiator, and stabilizer, the water content in the tert-butyl alcohol/water media, and the polymerization temperature. The average particle size of the lattices increased upon increasing the concentration of initiator, the polymerization temperature, and the water content in the tert-butyl alcohol/water media, but it decreased upon increasing the concentration of monomer and stabilizer. The viscosity-average molecular weight increased upon increasing the concentration of monomer and stabilizer and the water content in the tert-butyl alcohol/water media, but it decreased upon increasing both the concentration of initiator and the polymerization temperature.

• Journal of the korean academy of Pediatric Dentistry
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• 제23권3호
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• pp.764-773
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• 1996

The mutan containing $\alpha$-1,3 bond is an insoluble portion of glucan which is the main component of dental plaque. The secretion of mutanase was assessed with mutan-digesting Streptomyces isolated from soil, and the factors affecting its activity was studied, obtaining the following result. Mutan-digesting Streptomyces was identified as Streptomyces exfoliatus by its characteristics. The effect of dextranase was identified on the media containing blue dextran. A clear zone was produced by Streptomyces exfoliatus on the media containing blue mutan, so showing the secretion of mutanase. A clear zone was significantly produced on the media overlayed with agar containing blue mutan. A clear zone was produced at 2 days after the inoculation of Streptomyces exfoliatus on the media containing below a concentration of 0.025% glucose, at 3 days on the media containing 0.05 % glucose, and at 4 days on the media containing 0.1 % glucose. Mutan-digestion wasn't appeared early by adding other carbohydrates. The higher concentration of peptone, the later appearance of clear zone was on the media containing below a concentration of 0.1 % peptone. These results indicated that the secretion of mutanase was identified from mutan-digesting Streptomyces on the media containing blue mutan, and a clear zone was appeared lately on the media containing higher amount of glucose.

• Journal of Nutrition and Health
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• 제29권1호
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• pp.97-103
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• 1996

This study was performed to investigate the effects of lipid on cellular senescence, lipid peroxide production, and morphological changes. For this study we used primary skin fibroblasts from neonate rats grown in media various lipid contents. Fibroblasts were cultured until they lost their proliferation potential either in control medium (Dulbecco's modified Eagle's medium supplement with 10% fetal bovine serum) or in media supplemented with various concentrations of lipid-cholesterol rice component from bovine serum. Cumulative population doublings(CPD, as an index of cellular life span), and cellular thiobarbituric acid reactive substances (TBARS, as an index of lipid peroxide) concentrations were measured and morphological changes were observed. CPD were shortened with increasing lipid concentration in media ; 28.12 for cells grown in control medium and 13.42, 11.42, and 6.19 for those grown in 0.1%, 1% and 5% lipid rich components containing media, respectively. Cellular proliferation ratios were those grown in 5% lipid rich components containing media were delayed and they were degenerated soon. TBARS concentrations were increased with increasing concentration of lipid in media. Morphological changes were observed in cells grown in control medium by cellular senescence. Especially lipid droplets were observed in cells grown in 5% lipid rich components containing media. Therefore it seems that lipid contents in media had an effect on cellular proliferation and cellular life span, possibly via lipid peroxide production.

• Journal of Internet Computing and Services
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• 제12권4호
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• pp.51-59
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• 2011

The purpose of this study is to provide relevant directions of media industry regulation and policy by analyzing the relationship between market concentration and performance in global pay TV markets. The market concentration has long been regulated in the media industry under the belief that it harms market efficiency and cultural diversity. As the global media market is undergoing significant chance accelerated by the advance of technology, it is necessary to examine the feasibility of this long myth. The data are collected from global 17 pay TV markets and analyzed to see whether the highly concentrated markets by a single player result in higher price and slower service penetration. The result indicates that the price is not escalated and the penetration is not limited even in the markets where a dominant player takes high market share. It implies that more diverse factors other than the market concentration affect the market performance and that maintaining strict regulation of the market concentration is likely to have negative effect on technology innovation.

• Biomolecules & Therapeutics
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• 제30권2호
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• pp.184-190
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• 2022

Targeting the cystine/glutamate exchange transporter, system x_c^-, is a promising anticancer strategy that induces ferroptosis, which is a distinct form of cell death mediated by iron-dependent lipid peroxidation. The concentration of ⳑ-cystine in culture medium is higher than the physiological level. This study was aimed to evaluate the effects of ⳑ-cystine concentration on the efficacy of ferroptosis inducers in hepatocellular carcinoma cells. This study showed that treatment with sulfasalazine or erastin, a system x_c^- inhibitor, decreased the viability of Huh6 and Huh7 cells in a dose-dependent manner, and the degree of growth inhibition was greater in medium containing a physiological ⳑ-cystine concentration of 83 µM than in commercial medium with a concentration of 200 µM ⳑ-cystine. However, RSL3, a glutathione peroxidase 4 inhibitor, decreased cell viability to a similar extent in media containing both ⳑ-cystine concentrations. Sulfasalazine and erastin significantly increased the percentages of propidium iodide-positive cells in media with 83 µM ⳑ-cystine, but not in media with 200 µM ⳑ-cystine. Sulfasalazine- or erastin-induced accumulation of lipid peroxidation as monitored by C11-BODIPY probe was higher in media with 83 µM ⳑ-cystine than in media with 200 µM ⳑ-cystine. In contrast, the changes in the percentages of propidium iodide-positive cells and lipid peroxidation by RSL3 were similar in both media. These results showed that sulfasalazine and erastin, but not RSL3, were efficacious under conditions of physiological ⳑ-cystine concentration, suggesting that medium conditions would be crucial for the design of a bioassay for system x_c^- inhibitors.

• Journal of Environmental Health Sciences
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• 제35권3호
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• pp.201-208
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• 2009

Oxidation of phenol in aqueous media by electro-Fenton process using Ru-Sn-Sb/graphite electrode has been studied. Hydrogen peroxide was electrically generated by reaction of dissolved oxygen in acidic solutions containing supporting electrolyte and $Fe^{2+}$ was added in aqueous media. Phenol degradation experiments were performed in the presence of electrolyte media at pH 3. Effect of operating parameters such as current, electrolyte type (NaCl, KCl and $Na_2SO_4$) and concentration, $Fe^{2+}$ concentration, air flow rate and phenol concentration were investigated to find the best experimental conditions for achieving overall phenol removal. Results showed that current of 2 A, NaCl electrolyte concentration of 2g/l, 0.5M concentration of $Fe^{2+}$, air flow rate of 1l/min were the best conditions for mineralization of the phenol by electro-Fenton.

• Journal of Korean Society of Water and Wastewater
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• 제20권6호
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• pp.813-822
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• 2006

Soluble manganese removal was analyzed as a function of filter media, filter depth, presence or absence of chlorination, and surface manganese oxide concentration in water treatment processes. Sand, manganese oxide coated sand (MOCS), sand+MOCS, and granular activated carbon(GAC) were used as filter media. Manganese removal, surface manganese oxide concentration, turbidity removal, and regeneration of MOCS in various filter media were investigated. Results indicated that soluble manganese removal in MOCS was rapid and efficient, and most of the removal happened at the top of the filter. When filter influent (residual chlorine 1.0mg/L) with an average manganese concentration of 0.204mg/L was fed through a filter column, the sand+MOCS and MOCS columns can remove 98.9% and 99.2% of manganese respectively on an annual basis. On the other hand, manganese removal in sand and the GAC column was minimal during the initial stage of filtration, but after 8 months of filter run they removed 99% and 35% of manganese, respectively. Sand turned into MOCS after a certain period of filtration, while GAC did not. In MOCS, the manganese adsorption rate on the filter media was inversely proportional to the filter depth, while the density of media was proportional to the filter depth.

• Korean journal of communication and information
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• 제45권
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• pp.113-150
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• 2009

Attempts to relax cross-media ownership have been made by conservative Party and leading dailies. A concern with the cross-ownership of media is predominant in media and political spheres. This article is about the media market concentration created by cross-media ownership. This essay is a response to the demand of the ruling camp that attempts to concentrate on media market, and to increase their influence. I have outlined issues of cross ownership. The finding of this research supported the rationale of ban on cross ownership of newspaper and broadcasting outlet.

• KSBB Journal
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• 제16권4호
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• pp.332-336
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• 2001

This paper is intended as an application of the biological rope media sedimentation tank using biodegradability of BAC(Biological activated carbon) to the drinking water treatment system for the removal of NOM. The removal of DOC(Dissolved organic carbon), UV absorbance(UV$\_$254/), and turbidity were evaluated under various operation condition of a biological rope media sedimentation tank such as raw water-media process (Media 1), ozonation-media process (Media 2), and ozonation-coagulation/sedimentation-media process (Media 3). The raw water had DOC concentration of 1.3∼3.4 mg/L, UV$\_$254/ of 0.027∼0.039 cm$\^$-1/, and turbidity of 0.3∼4.5 NTU, respectively. The average DOC concentration were 2.2 mg/L in media 1, 1.8 mg/L in media 2, and 1.3 mg/l in media 3 from raw water, respectively. On the other hand, the DOC concentration in conventional sedimentation tank was 1.5 mg/l. Higher removal of the DOC was noted in media 3 than media 1 and media 2. The UV$\_$254/ of the treated water were 0.037 cm$\^$-1/ in media 1, 0.027 cm$\^$-1/ in media 2, and 0.014 cm$\^$-1/ in media 3 from raw water, respectively The UV$\_$254/ in conventional sedimentation tank was 0.014 cm$\^$-1/ which is similar to that of media 3. Average turbidity of the treated water was 1.1 NTU in media 1, 0.9 NTU in media 2, and 0.5 NTU in media 3, respectively. It is expected that the biological rope media sedimentation tank is a good alternative over the conventional sedimentation process from these results.