• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.102-105
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• 2007

The performance evaluation of the micro thruster utilizing hydrogen peroxide decomposition is described. The catalyst bed was made of porous ceramic material($Isolite^{(R)}$) with large surface to mass ratio. 14%wt platinum was loaded on the catalyst support as a catalyst. Hydrogen peroxide with 85% concentration was used as a monopropellant. The length of the catalyst bed and the feed pressure of the hydrogen peroxide were taken as the parameters for the experiment. All experiments were carried out under cold start condition for 30 seconds. The $c^*$ efficiency was evaluated for each test case using measured pressure data. For the catalyst support length of 30 mm and feed pressure at 5.51 bar, satisfactory $c^*$ efficiency beyond 95% was observed.

• Journal of Microbiology
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• v.44 no.2
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• pp.206-216
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• 2006

In this study, we have attempted to characterize the functions of YlaC and YlaD encoded by ylaC and ylaD genes in Bacillus subtilis. The GUS reporter gene, driven by the yla operon promoter, was expressed primarily during the late exponential and early stationary phase, and its expression increased as the result of hydrogen peroxide treatment. Northern and Western blot analyses revealed that the level of ylaC transcripts and YlaC increased as the result of challenge with hydrogen peroxide. A YlaC-overexpressing strain evidenced hydrogen peroxide resistance and a three-fold higher peroxidase activity as compared with a deletion mutant. YlaC-overexpressing and YlaD-disrupted strains evidenced higher sporulation rates than were observed in the YlaC-disrupted and YlaD-overexpressing strains. Analyses of the results of native polyacrylamide gel electrophoresis of recombinant YlaC and YlaD indicated that interaction between YlaC and YlaD was regulated by the redox state of YlaD in vitro. Collectively, the results of this study appear to suggest that YlaC regulated by the YlaD redox state, contribute to oxidative stress resistance in B. subtilis.

• The Korean Journal of Physiology and Pharmacology
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• v.11 no.5
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• pp.171-174
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• 2007

Neuronal death is a common characteristic hallmark of a variety of neurodegenerative disorders including Alzheimer's disease and Parkinson's disease. However, there have been no effective drugs to successfully prevent neuronal death in those diseases, whereas oriental medicinal plants have to possess valuable therapeutic potentials to treat neurodegenerative diseases. In the present study, in an attempt to provide neuroprotective agents from natural plants, 80% methanol extracts of a wide range of medicinal plants, which are native to Jeju Island in Korea, were prepared and their protective effects on hydrogen peroxide-induced apoptotic cell death were examined. Among those tested, extracts from Smilax china and Saururus chinesis significantly decreased hydrogen peroxide-induced apoptotic cell death. The extracts attenuated hydrogen peroxide($H_2O_2$)-induced caspase-3 activation in a dose-dependent manner. Further, plant extracts restored $H_2O_2$-induced depletion of intracellular glutathione, a major endogenous antioxidant. The data suggest that Jeju native medicinal plants could potentially be used as therapeutic agents for treating or preventing neurodegenerative diseases in which oxidative stress is implicated.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.235-238
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• 2007

There is great interest in the applicability of generated hydrogen peroxide to a variety of industrial processes, usually involving oxidation of organics. Hydrogen peroxide is now employed for the bleaching as well as mechanical and chemical treatment in the pulp and paper industries. It addition, it is considered as an agent to displace the traditional alkaline treatments with chlorine-based chemicals. This paper reports a comparative study of $H_2O_2$ electogeneration on gas-diffusion electrode in divided cell with several $Nafion^{(R)}$ proton-exchange membranes, Russian cation-exchange membrane MK-40 and SPEEK membrane. The influence of different PEMs on electro-chemical cell voltage, current efficiency and energy consumption of hydrogen peroxide generation has been studied.

• Journal of the Korean Chemical Society
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• v.39 no.12
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• pp.932-939
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• 1995

Rates of the decomposition of hydrogen peroxide by copper(Ⅱ)-Schiff base complexes were measured at various concentrations of hydrogen peroxide. Decomposition rates of hydrogen peroxide increased with increasing pH for CuⅡBSDT and CuⅡBSTP but then decreased with the same variation of the pH for CuⅡBSTT. A possible mechanism in accord with experimental results was proposed. The mechanism involves the deprotonation of copper(Ⅱ)-Schiff base complexes of hydrogen peroxide, followed by the formation of peroxo complexes at the rate-determining step.

• YAKHAK HOEJI
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• v.54 no.1
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• pp.32-38
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• 2010

The aim of this study was to evaluate the effect of galangin towards hydrogen peroxide-induced DNA damage. The calf thymus DNA and Chinese Hamster Lung (CHL) cells were used to measure 8-hydroxy-2'-deoxyguanosine(8-OH2'dG) as an indicator of DNA oxidative damage using high performance liquid chromatography with electrochemical detection. Hydrogen peroxide in the presence of Fe(II) ion induced the formation of 8-OH2'dG in both calf thymus DNA and CHL cells. The DNA damage effects were enhanced by increasing the concentration of Fe(II) ion and inhibited by galangin. In the single cell gel electrophoresis (Comet assay), galangin and dl-a-tocopherol showed an inhibitory effect in CHL on hydrogen peroxide induced DNA single strand breaks. Galangin showed more potent activity than dl-$\alpha$-tocopherol under our experimental conditions. These results indicate that galangin can modify the action mechanisms of the oxidative DNA damage and may act as chemopreventive agents against oxidative stress.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.11
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• pp.1454-1464
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• 2005

The study was based on a three-stage, non-repetitive factorial experiment in which chemical-rotted kenaf fibers were treated separately with hydrogen peroxide concentrations of $0.5\%,\;1\%\;and\;2\%$, with pH solutions of 7, 9 and 11, and treatment times of 30, 60 and 90 minutes. Under optimal conditions, the study was conducted to determine the strength and elongation of kenaf fibers by the addition of chelators, penetrants and surfactants. The hydrogen peroxide concentration, solution pH and treatment time directly affected the strength of kenaf fibers. The hydrogen peroxide concentration, solution pH affected the elongation of kenaf fibers. It was found, however, that the interaction between pH and treatment time, concentration and treatment time, concentration and treatment time and pH affected the strength of kenaf fibers. Also, It was found that the interaction between pH and concentration, concentration and treatment time, concentration and treatment time and pH affected the elongation of kenaf fibers. Under the hydrogen peroxide conditions of $2\%$ concentration, pH 11 and a treatment time of 60 minutes, there were no effects on the strength and elongation of kenaf fibers with the addition of chelator SP, CA.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.397-400
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• 2008

Traditional propellants which have a hypergolic characteristic have a high performance but also have disadvantages of toxicity and complex handling requirement. In order to replace these propellants, one of the alternatives is hydrogen peroxide which generates high temperature oxygen and water vapor after catalytic reaction. In this paper, autoignition characteristics of kerosene by decomposed hydrogen peroxide were investigated to perform fundamental research for designing a thruster using hydrogen peroxide and kerosene propellants. Contraction ratio, whether flame holder exists or not, and feeding pressure of propellants were selected as variables. From the experiments for different mixture ratio, we confirmed the ignition stability is strongly affected by a feeding pressure of propellants.

• The Korean Journal of Food And Nutrition
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• v.35 no.4
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• pp.259-267
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• 2022

The purpose of this study was to evaluate the antioxidative activities of jeolpyun containing Cnidium officinale M extract (2%, 4%, 6%, 8%) by total polyphenol contents, electron donating ability on 2,2-diphenyl-1-picrylhydrazyl (DPPH), scavenging ability of superoxide anion radical and decomposing ability of hydrogen peroxide. In chromaticity analysis, the brightness significantly decreased with increasing Cnidium officinale M extract content. Jeolpyun containing 8% Cnidium officinale M extract revealing the highest value for the redness and the yellowness, 1.07, 12.70, respectively. The total polyphenol contents of jeolpyun containing 8% Cnidium officinale M extract were the highest content of 4,213 ㎍ gallic acid equivalent (GAE)/mL. The total polyphenol contents revealed significant difference (p<0.05). Jeolpyun containing 8% Cnidium officinale M extract revealing the highest electron donating ability (83.55%). The electron donating abilities were significantly related at p<0.05. The scavenging abilities of superoxide anion radical for jeolpyun containing 4% Cnidium officinale M extract revealed the highest ability (0.01676). There was no significant difference. The hydrogen peroxide decomposing ability for jeolpyun containing 8% Cnidium officinale M extract revealed the most hydrogen peroxide decomposing ability (-0.193) and the hydrogen peroxide decomposing ability revealed a significant difference (p<0.05).

• Journal of Korean Clinical Health Science
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• v.11 no.1
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• pp.1625-1631
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• 2023

Purpose The The purpose of this study was to clinically evaluate the efficacy and safety of a self-whitening patch containing a primer containing taurine and 3.0% hydrogen peroxide. Methods A double-blind randomized clinical trial was conducted on 55 subjects. The whitening patches containing 3.0% hydrogen peroxide were applied to the labial surfaces of maxillary six anterior teeth once daily for 30 minutes using a primer, and whitening efficacy was measured by △E^* values before application and at 3, 5, 7, and 10 days after application. Stability was determined using the Gingival index (GI) and visual analogue scale (VAS). Results Changes in △E^* values were clinically recognizable as early as day 5 after patch application, and whitening effects were visible by day 7. There was no statistically significant difference in gingival index (p=0.069). Conclusions Self-whitening patches using primer and 3.0% hydrogen peroxide applied once daily for 30 minutes showed effective whitening effect from the 5th day after application and could be used safely without significant side effects.