• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.280-285
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• 2015

Anti-oxidative and anti-inflammatory activities of Cotoneaster horizontalis Decne ethanol extract (CHEE) were evaluated. CHEE possessed a potent scavenging activity against 1,1-diphenyl-2-picryl hydrazyl, which was similar to the activity of ascorbic acid which was used as a positive control. CHEE also effectively suppressed hydrogen peroxide-induced reactive oxygen species on RAW 264.7 cells. Furthermore, CHEE induced the expression of the anti-oxidative enzyme heme oxygenase 1, and its upstream transcription factor, nuclear factor-E2-related factor 2. CHEE inhibited LPS induced nitric oxide (NO) formation as a consequence of inducible NO synthase (iNOS) down regulation. Taken together, these results provide us with an important new insight; that C. horizontalis possesses anti-oxidative and anti-inflammatory activities. Therefore, C. horizontalis may be utilized as a promising material in the field of nutraceuticals.

• Korean Journal of Animal Reproduction
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• v.20 no.4
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• pp.427-432
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• 1997

These studies were performed to approach the precise pathway inducing the meiotic inhibitory action of hypoxanthine on mouse follicular oocytes and to identify the cause of detrimental effect of hypoxanthine on viability of the oocyte in vitro. In addition, a correlation between the meiotic inhibitory effect and the detrimental effect of hypoxanthine was investigated. Mouse follicular oocytes at germinal vesicle(GV) stage were collected from the ovaries of ICR mice by puncturing the antral follicles with a fine needle, at 48 hours after PMSG injection. Oocytes were cultured in Modified Whittingham's T6 media containing hypoxanthine and several materials that involved in metabolism of hypoxanthine, and the effects of the materials on the actions of hypoxanthine were investigated by observing germinal vesicle breake down (GVBD), 1st polar body (PB) extrusion and viability of the oocytes. Phophodiesterase significantly reduced the meiotic inhibitory effect of dbcAMP but did not influence on the inhibitory effect of hypoxanthine. Allopurinol and 6-MP significantly enhanced the meiotic inhibitory effect of hypoxanthine, but the materials themselves also showed the meiotic inhibitory action like hypoxanthine. Hypoxanthine-guanine phosphoribosyltransferase significantly enhanced the meiotic inhibitory effect of hypoxanthine, on the contrary HGPRT itself promoted meiotic resumption of the oocytes. Catalase did not induce any change in the meiotic inhibitory effect of hypoxanthine, but SOD increased the GVBD rate suppressed by hypoxanthine. The detrimental effect of hypoxanthine on viability of the oocytes was significantly reduced by allopurinol and catalase, but SOD increased the GVBD rate suppressed by hypoxanthine. The detrimental effect of hypoxanthine on viability of the oocytes was significantly reduced by allopurinol and catalase, but SOD did not reduce the deterimental effect of hypoxanthine. In conclusion, the meiotic inhibtory effect of hypoxanthine may be caused by guanyl dervartives converted from hypoxanthine via salvage pathway, and superoxide anion may partially participate in the inhibitory effect of hypoxanthine. The detrimental effect of hypoxanthine on viability of the oocytes be cused by hydrogen peroxide produced during the metabolism of hypoxanthine.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.1
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• pp.41-47
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• 2005

Preparation of ferrocyanide-anion exchange resin and adsorption test of the prepared resin on the Cs$^{+}$$ion were performed. Adsorption capability of the prepared resin on the Cs$^{+}$ion in the simulated citric acid based soil decontamination waste solution was 4 times greater than that of the commercial cation exchange resin. Adsorption equilibrium of the prepared resin on the Cs$^{+}$ion reached within 360 minutes. Adsorption capability on the Cs$^{+}$ion became to decrease above the necessary Co$^{2+}$ion concentration in the experimental range. Recycling test of the spent ion exchange resin by the successive application of hydrogen peroxide and hydrazine was also performed. It was found that desorption of Cs$^{+}$ion from the resin occurred to satisfy the electroneutrality condition without any degradation of the resin.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.197-199
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• 2017

Using the InfraRed Camera (IRC) on board the infrared astronomical satellite AKARI we study the ${3.3{\mu}m}$ polycyclic aromatic hydrocarbon (PAH) feature and its connection to active galactic nucleus (AGN) properties for a sample of 54 hard X-ray selected bright AGN, including both Seyfert 1 and Seyfert 2 type objects. The sample is selected from the 9-month Swift/BAT survey in the 14-195 keV band and all of the sources have known neutral hydrogen column densities ($N_H$). The ${3.3{\mu}m}$ PAH luminosity ($L_{3.3{\mu}m}$) is used as a proxy for star-formation (SF) activity and hard X-ray luminosity ($L_{14-195keV}$) as an indicator of the AGN power. We explore for possible difference of SF activity between type 1 (un-absorbed) and type 2 (absorbed) AGN. We use several statistical analyses taking the upper-limits of the PAH lines into account utilizing survival analysis methods. The results of our log($L_{14-195keV}$) versus log($L_{3.3{\mu}m}$) regression shows a positive correlation and the slope for the type 1/unobscured AGN is steeper than that of type 2/obscured AGN at a $3{\sigma}$ level. Also our analysis shows that the circum-nuclear SF is more enhanced in type 2/absorbed AGN than type 1/un-absorbed AGN for low $L_{14-195keV}$ luminosity/low Eddington ratio AGN, while there is no significant dependence of SF activity on the AGN type in the high $L_{14-195keV}$ luminosities/Eddington ratios.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.11
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• pp.2305-2311
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• 2002

The pressure tube is a major component of the CANDU reactor, which supports nuclear fuel bundle and heavy water coolant. Pressure tubes are installed horizontally inside the reactor and only selected samples are periodically examined during in-service inspection. In this respect, a probabilistic safety assessment method is more appropriate fur the assessment of overall pressure tube safety. The failure behavior of CANDU pressure tubes, however, is governed by delayed hydride cracking which is the major difference from pipings and reactor pressure vessels. Since the delayed hydride cracking has more widely distributed governing parameters, it is impossible to apply a general PFM methodology directly. In this paper, a PFM methodology for the safety assessment of CANDU pressure tubes is introduced by applying Monte Carlo simulation in determining failure probability Initial hydrogen concentration, flaw shape and depth, axial and radial crack growth rate and fracture toughness were considered as probabilistic variables. Parametric study has been done under the base of pressure tube dimension and hydride precipitation temperature in calculating failure probability. Unstable fracture and plastic collapse are used for the failure assessment. The estimated failure probability showed about three-order difference with changing dimensions of pressure tube.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.107-111
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• 2005

We have performed a study on the electrochemical characteristics and nuclear ($^7Li$) magnetic resonance of $V_2O_5$ xerogels that have been synthesized by the sol-gel reaction of $V_2O_5$ powder with hydrogen peroxide. NMR measurements revealed that chemical shift of $Li^+$ ions varied as lithium ions were inserted into $V_2O_5$ xerogel and that several different sites for $Li^+$ ions existed in the $V_2O_5$ xerogel structure. The electrochemical properties of the xerogel electrodes did not depend much upon the concentration of $V_2O_5$ and HCl that were used for the synthesis of $V_2O_5$ gels. The specific capacity of $V_2O_5$ xerogels were about 140 mAh/g, similar to that of the xerogels prepared by the ion exchange method.

• Nutrition Research and Practice
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• v.9 no.2
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• pp.123-128
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• 2015

BACKGROUND/OBJECTIVES: Natural products or active components with a protective effect against oxidative stress have attracted significant attention for prevention and treatment of degenerative disease. Oligonol is a low molecular weight polyphenol containing catechin-type monomers and oligomers derived from Litchi chinensis Sonn. We investigated the protective effect and its related mechanism of oligonol against oxidative stress. MATERIALS/METHODS: Oxidative stress in C6 glial cells was induced by hydrogen peroxide ($H_2O_2$) and the protective effects of oligonol on cell viability, nitric oxide (NO) and reactive oxygen species (ROS) synthesis, and mRNA expression related to oxidative stress were determined. RESULTS: Treatment with oligonol inhibited NO and ROS formation under cellular oxidative stress in C6 glial cells. In addition, it recovered cell viability in a dose dependent-manner. Treatment with oligonol also resulted in down-regulated mRNA expression related to oxidative stress, nuclear factor kappa-B (NF-${\kappa}B$) p65, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS), compared with the control group treated with $H_2O_2$. In particular, expression of NF-${\kappa}B$ p65, COX-2, and iNOS was effectively reduced to the normal level by treatment with $10{\mu}g/mL$ and $25{\mu}g/mL$ of oligonol. CONCLUSIONS: These results indicate that oligonol has protective activity against oxidative stress-induced inflammation. Oligonol might be a promising agent for treatment of degenerative diseases through inhibition of ROS formation and NF-${\kappa}B$ pathway gene expression.

• Nutrition Research and Practice
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• v.9 no.4
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• pp.364-369
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• 2015

BACKGROUND/OBJECTIVES: Inflammation is associated with various types of acute and chronic alcohol liver diseases. In this study, we examined whether umbelliferone (7-hydroxycoumarin, UF) ameliorates chronic alcohol-induced liver damage by modulating inflammatory response and the antioxidant system. METHODS: Rats were fed a Liber-Decarli liquid diet containing 5% alcohol with or without UF (0.05 g/L) for 8 weeks, while normal rats received an isocaloric carbohydrate liquid diet. RESULTS: Chronic alcohol intake significantly increased serum tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and interleukin 6 levels and decreased interleukin 10 level; however, UF supplementation reversed the cytokines related to liver damage. UF significantly suppressed hepatic lipopolysaccharide binding protein, toll-like receptor 4 (TLR4), nuclear factor kappa B, and TNF-${\alpha}$ gene expression increases in response to chronic alcohol intake. Masson's trichrome staining revealed that UF improved mild hepatic fibrosis caused by alcohol, and UF also significantly increased the mRNA expressions and activities of superoxide dismutase and catalase in liver, and thus, decreased lipid peroxide and mitochondrial hydrogen peroxide levels. CONCLUSIONS: The findings of this study indicate that UF protects against alcohol-induced liver damage by inhibiting the TLR4 signaling pathway and activating the antioxidant system.

• Korean Journal of Materials Research
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• v.9 no.4
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• pp.378-385
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• 1999

To evaluate the effect of Sn on the corrosion behavior of Zr alloys for nuclear fuel claddings, the corrosion tests on the binary Zr-xSn and the ternary Zr-0.4Nb-xSn alloys were performed in water at $360^{\circ}C$. The binary alloys containing 0.5, 0.8 and 1.5wt.% Sn showed the transition corrosion rate at 15 days. On the other hand, the binary alloy containing 2.0wt.% Sn showed a good corrosion resistance without the transition of corrosion rate up to 80 days. The corrosion rate of the ternary alloy increased with increasing Sn content. The difference of corrosion behaviors between binary and ternary alloys is considered due to the different solubility of Sn, Nb content and precipitates. The corrosions of Zr-xSn and Zr-0.4Nb-xSn alloys would be controlled by the fraction of tetragonal-$ZrO_2$and the amount of hydrogen pick-up.

• BMB Reports
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• v.48 no.11
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• pp.636-641
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• 2015

There are controversial findings regarding the roles of nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway on bone metabolism under oxidative stress. We investigated how Nrf2/HO-1 pathway affects osteoblast differentiation of MC3T3-E1 cells in response to hydrogen peroxide (H₂O₂), N-acetyl cysteine (NAC), or both. Exposing the cells to H₂O₂ decreased the alkaline phosphatase activity, calcium accumulation, and expression of osteoblast markers, such as osteocalcin and runt-related transcription factor-2. In contrast, H₂O₂ treatment increased the expression of Nrf2 and HO-1 in the cells. Treatment with hemin, a chemical HO-1 inducer, mimicked the inhibitory effect of H₂O₂ on osteoblast differentiation by increasing the HO-1 expression and decreasing the osteogenic marker genes. Pretreatment with NAC restored all changes induced by H₂O₂ to near normal levels in the cells. Collectively, our findings suggest that H₂O₂-mediated activation of Nrf2/HO-1 pathway negatively regulates the osteoblast differentiation, which is inhibited by NAC.