• Transactions of the Korean hydrogen and new energy society
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• v.20 no.4
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• pp.274-282
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• 2009

Diaphragm compressor is widely used for hydrogen compression because it achieves high gas pressure without gas contamination. Diaphragm deflecting in the cavity with high pressure formed by an oil compression is the most important component in the compressor. Therefore, it is necessary to obtain deflection degree of diaphragm to predict the damage point of diaphragm. The objective of this study is to estimate the diaphragm's damage point through diaphragm deflection test by implementing with strain gauges attached on several radial points. Without gas compression, strain sum of each points varied as similarly as the variation of the pressure with respect to time. And while the motor speed was slower than 400rpm, the strain near the rim was larger than that of the center. When motor speed, however, was over 500rpm, strain became similar to that of the center and the rim. With gas compression, it was shown that the variation of the strain sum was delayed against that of the pressure and the strain near the rim was much higher than that of the center.

• Korean Journal of Veterinary Research
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• v.42 no.2
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• pp.153-162
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• 2002

For the induction of arthropathy, 5% hydrogen peroxide($H_2O_2$) was injected for 5 weeks into the intraarticular space of the New Zealand white rabbits to damage articular cartilage. Alginic acid of low molecular weight (2%) made from macromolecular alginate treated with enzyme was administered into articular space at the dose of 5 mg/kg twice a week for 3 and 6 weeks using 1 ml syringe and 26 G needle. Saline was injected for the control. Tissues surrounding the articulation were obtained for the measurements of superoxide dismutase(SOD) activity as a major antioxidant enzyme and malondialdehyde (MDA) as a lipid peroxidation level. Histopathologic examination on the surface of articular cartilage was carried out. Data showed that injection of hydrogen peroxide for 5 weeks had led to the induction of free radical damage and of articular cartilage change as confirmed by microscopic observation. The application of hydrogen peroxide caused a gradual increase in the SODs and MDA. These patterns were similar after 3 and 6 weeks of alginate treatment. Furthermore, microscopic examinations revealed that hydrogen peroxide caused flaking, fibrillation, fissuring, denudation, and hypocellularity in the articular surfaces. In conclusion, lipid peroxidation was demonstrated in the articular cartilage by the administration of hydrogen peroxide in the rabbit model. This lipid peroxidation could be caused by oxygen free radicals. The histologic and enzymatic correlations on lipid peroxidation in the articulation have provided a better understanding of arthropathy. It is possible to take advantage of these findings to evaluate effective alginate dosage more efficiently.

• Biomolecules & Therapeutics
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• v.20 no.5
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• pp.487-491
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• 2012

The aim of this study was to investigate the inhibitory effects of rutaecarpine on DNA strand breaks and apoptosis induced by hydrogen peroxide ($H_2O_2$) in murine Hepa-1c1c7 cells. Oxidative DNA damage was estimated by nuclear condensation assessment, fluorescence-activated cell sorting analysis, and Comet assay. Rutaecarpine inhibited cell death induced by $500{\mu}M$ $H_2O_2$, as assessed by 4',6-diamidino-2-phenylindole (DAPI) staining. Treatment with rutaecarpine reduced the number of DNA strand breaks induced by $H_2O_2$, as assessed by DAPI staining and Comet assay, and increased quinone reductase, phosphatidylinositol 3-kinase, and pAkt protein levels, as assessed by western blotting.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.343-348
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• 2008

In this study, antioxidant activity of methanol extract of Glycyrrhiza uralensis Fisch (GUE) against $H_2O_2$-induced DNA damage in human leucocytcs and cell death in PC12 cells was determined. The effect of GUE on $H_2O_2$-induced DNA damage in human leucocytcs was evaluated by the comet assay, where GUE ($1-50\;{\mu}g/mL$) was a dose dependent inhibitor of DNA damage induced by $H_2O_2$. The protective effect of GUE against $H_2O_2$-induced damage on PC12 cells was investigated by MTT reduction assay and lactate dehydrogenase release assay. A marked reduction in cell survival induced by $H_2O_2$ was significantly prevented by $1-50\;{\mu}g/mL$ of GUE. The enzyme activity of caspase-3 was elevated in $H_2O_2$-treated PC12 cells, while preincubation with GUE for 30 min inhibited $H_2O_2$-induced caspase-3 activation in a dose-dependent manner. In conclusion, GUE ameliorates $H_2O_2$-induced DNA damage in human leucocytes and has neuroprotective effect by preventing cell death in PC12 cell, suggesting that GU may be a potential candidate for novel therapeutic agents for neuronal diseases associated with oxidative stress.

• Korean Journal of Plant Resources
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• v.24 no.2
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• pp.130-138
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• 2011

In this study, we evaluated the protective effects of the hot water extract from red bean (Phaseolus angularis) against oxidative DNA and cell damage induced by hydroxyl radical. The antioxidant activities were evaluated by hydroxyl radical and hydrogen peroxide scavenging assay, and $Fe^{2+}$-chelating assay. Although the extract with hot water didn't scavenge the hydroxyl radical, it removed and chelated hydrogen peroxide and ferrous iron necessary for the induction of hydroxyl radical by 71% and 64% at 200 ${\mu}g/ml$, respectively. Its protective effect on oxidative DNA damage was carried using ${\Psi}$X-174 RF I plasmid DNA comparing the conversion level of supercoiled form of the plasmid DNA into open-circular form and linear form and the expression level of phospho-H2AX in NIH 3T3 cells. In ${\Psi}$X-174 RF I plasmid DNA cleavage assay, it inhibited oxidative DNA damage by 96% at 200 ${\mu}g/ml$. Also, it decreased the expression of phospho-H2AX by 50.1% at 200 ${\mu}g/ml$. Its protective effect against oxidative cell damage was measured by MTT assay and the expression level of p21 protein in NIH 3T3 cells. In MTT assay for the protective effect against the oxidative cell damage, it inhibited the oxidative cell death and the abnormal cell growth induced by hydroxyl radical. Also, it inhibited p21 protein expression by 98% at 200 ${\mu}g/ml$. In conclusion, the results of the present studies indicate that hot water extract from red bean exhibits antioxidant properties and inhibit oxidative DNA damage and the cell death caused by hydroxyl radical.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.8
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• pp.974-980
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• 2014

Aluminum acts as sacrificial anode and corrosion protection with Al2O3 formation. If the same current on material for Al ships with steel ships supplies, the more hydrogen would be occurred, that result is bring about over-protection. For this reason, the damage by hydrogen embrittlement leads to the serious accident. In this study, we evaluate electrochemical behavior with rotation speed of 5083-H116 Al alloy material for Al ship in seawater. To examine the electrochemical characteristics with rotation speed and its effects on performance, experiments were conducted at four rotation speed. Results of experiments, the corrosion current density and damage were increased by applying the rotation speed compared to static state.

• Journal of Welding and Joining
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• v.30 no.6
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• pp.10-14
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• 2012

Recently the low alloy steel plate made with manganese-molybdenum is used widely in steam drum and separator of the new coal-fired power plant boiler. This material is suitable for the vapor storage of high pressure and high temperature. The high temperature creep strength of Mn-Mo alloy is higher than the carbon plate(SA516) that used in the subcritical pressure boiler. It reduces the thickness of the pressure vessel and makes the lightweight possible. Recently in the power plant boiler operation and production process, the damage has happened frequently in the heat affected zone and base material according to the hydrogen crack and delayed crack. This paper describes the research result about the damage case experienced in the boiler steam drum production process and present the optimum manufacture method for the similar damage prevention of recurrence.

• Biomolecules & Therapeutics
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• v.13 no.3
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• pp.150-155
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• 2005

The ethanolic extract of chestnut (Castanea crenata S. et Z., Fagaceae) inner shell (CISE) and one of its components, ellagic acid (EA), were evaluated for their protective effects against 1, 1-diphenyl-2-picryl hydrazine (DPPH) free radical generation and hydrogen peroxide-induced oxidative DNA damage in a mammalian cell line. CISE and EA were shown to possess the free radical scavenging effect against DPPH radical generation, significantly. They were also found to strongly inhibit hydrogen peroxide-induced DNA damage from Chinese hamster lung (CHL) cell, assessed by single cell gel electrophoresis assay and 8-hydroxy -2'-deoxy guanosine (8-OH-2'dG) assay. Furthermore, topical application of CISE [$12.5\%$(w/w) cream] and ellagic acid [$1.0\%$(w/w) cream] for 14 days potently inhibited malondialdehyde (MDA) formation of mouse dorsal skin (a marker of lipid peroxidation) induced by ultraviolet B exposure. Therefore, CISE and its component, ellagic acid, may be the useful natural antioxidants by scavenging free radicals, inhibition of lipid peroxidation and protecting oxidative DNA damage when topically applied.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.61-61
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• 2003

The ethanol extract of peony root (Paeonia Lactiflora Pall, Paeoniaceae) and its major active components including gallic acid and methyl gallate were evaluated for their protective effects against free radical generation and lipid peroxidation. And protective effects against hydrogen peroxide-induced oxidative DNA damage in a mammalian cell line were performed. The ethanol extract of peony root (PRE), gallic acid and methyl gallate were shown to possess the significant free radical scavenging effect against 1,1-diphenyl-2-picryl hydrazine (DPPH) radical generation and were revealed the inhibitory effect of lipid peroxidation as expressed by malondialdehyde (MDA) formation. They were also found to strongly inhibit hydrogen peroxide-induced DNA damage from NIH/3T3 fibroblasts, assessed by single cell gel electrophoresis. Furthermore, oral administration of 50% PRE (50% ethanol extract), gallic acid and methyl gallate potently inhibited micronucleated reticulocyte (MNRET) formation of mouse peripheral blood induced by KBrO3 treatment in vivo. Therefore, PRE containing gallic acid and methyl gallate may be a useful natural antioxidant by scavenging free radicals, inhibition of lipid peroxidation and protecting oxidative DNA damage.

• Archives of Pharmacal Research
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• v.28 no.7
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• pp.775-783
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• 2005

The ethanol extract of the peony root (Paeonia Lactiflora Pall, Paeoniaceae) as well as its major active components including gallic acid and methyl gallate were evaluated for their protective effects against free radical generation and lipid peroxidation. In addition, the protective effects against hydrogen peroxide-induced oxidative DNA damage in a mammalian cell line were examined. The ethanol extracts of the peony root (PREs) and its active constituents, gallic acid and methyl gallate, exhibited a significant free radical scavenging effect against 1,1-diphenyl-2-picryl hydrazine (DPPH) radical generation and had an inhibitory effect on lipid peroxidation, as measured by the level of malondialdehyde (MDA) formation. The PREs did not have any pro-oxidant effect. They strongly inhibited the hydrogen peroxide-induced DNA damage from NIH/3T3 fibroblasts, as assessed by single cell gel electrophoresis. Furthermore, the oral administration of 50% PRE (50% ethanol extract of peony root), gallic acid and methyl gallate potently inhibited the formation of micronucleated reticulocytes (MNRET) in the mouse peripheral blood induced by a $KBrO_3$ treatment in vivo. Therefore, PREs containing gallic acid and methyl gallate may be a useful antigenotoxic antioxidant by scavenging free radicals, inhibiting lipid peroxidation and protecting against oxidative DNA damage without exhibiting any pro-oxidant effect.