• Journal of Nutrition and Health
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• v.32 no.3
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• pp.318-326
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• 1999

Apoptotic cell death, characterized by DNA fragmentation and morphological changes, has previously been shown to occur in vascular endothelial cells cultured with hydrogen peroxide. The present study examined the induction of apoptosis by hydrogen peroxide and whether pyruvate, a key glycolytic intermediate and $\alpha$-keto-monocarboxylate, can inhibit the apoptotic effects in bovine pulmonary artery endothelial cells(BPAECs). Culture with 500uM hydrogen peroxide resulted in 30% cell death and induced morphological changes and DNA fragmentation. Cell injury was inhibited by the treatment with pyruvate. Pyruvate(0.1-5.0mM), and cell viability increased in a dose-dependent manner. In the presence of pyruvate(10~20mM), the viability was improved to over 95%. In contrast, treatment with lactate, a reduced form of phyuvate, did not protect against cell death oxidative stress-induced loss of viability and apoptosis was examined with $\alpha$-cyano-3-hydroxycinnarmate(COHC) as a selective mitochondrial monocarboxylate transport blocker. Incubation with COHC(500uM) did not significantly affect cell viability in the presence of hydrogen peroxide. The cytoprotection by pyruvate(3mM)against hydrogen peroxide stress was abolished by COHC. This indicates that the cytoprotection by pyruvate against oxidative stress in endothelial cells is mediated, at least in part, by mitochondrial pyruvate uptake and hence endothelial enerygetics. However, cytosolic mechanisms related, at least in part, by mitochondrial pyruvate uptake and hence endothelial energetics. However, cytosolic mechanisms related to the glutathione system may also contribute. The results suggest that pyruvate has therapeutic potential in the treatment of oxidative stress-induced cytotoxicity associated with increased apoptosis.

• Journal of Hydrogen and New Energy
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• v.13 no.2
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• pp.127-134
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• 2002

A Study on the application of ultrasonic with high frequency is carried out as a plan to rise the efficiency of the hydrogen fuel production in an electrolysis of water. KOH is selected as an electrolyte and concentrations are 0 %, 10 %, 20 %, and 30%. The solvent is city water. A measurable device of buoyancy by an electronic balance and a measurable device of voltage with a sensor of pressure are planned newly as a measuring device to measure the quantity of hydrogen production. An ultrasonic transducer with high frequency of 2 MHz is selected to give them the ultrasonic forcing. In results, it is clarified that ultrasonic influences the decrease of overpotential in the electrolytic solution. And basic data according to the pole interval and the temperature are obtained.

• Journal of Hydrogen and New Energy
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• v.3 no.2
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• pp.45-54
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• 1992

An applicability microencapsulation, using electroless copper plating, of hydrogen storage alloy powder as an anode material for nickel-hydrogen secondary batteries was investigated. Alloys employed were $LaNi_{4.7}Al_{0.3}$ and $MmNi_{4.5}Al_{0.5}$(Mm=mischmetal) which have an appropriate equilibrium pressure and capacity. The microencapsulation of the alloy powder was found to accelerate initial activation of electrodes and to increase capacity which is about 285mAh/g for $LaNi_{4.7}Al_{0.3}$. In addition, other charge and discharge characteristics, such as polarization and flatness of charge and discharge potential, were improved due to the role of copper layer as a microcurrent collector and an oxidation barrier of the alloy powder. $MmNi_{4.5}Al_{0.5}$ alloy showed lower capacity than $LaNi_{4.7}Al_{0.3}$ because of higher equilibrium pressure. Cyclic characteristics of both alloys were somewhat poor because of mainly shedding and partial oxidation of alloy powder during the cycling. However, it was considered that the microencapsulation method is effective to improve the performances of the hydrogen storage alloy electrodes.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.25-25
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• 2000

In this talk we discuss the dynamics of hydrogen on the Si(100)-2xl surface. At room temperature the sticking coefficient for molecular hydrogen on this surface is less than 10sup-12. However, hydrogen molecules desorbing from the surface do not have an excess of energy, suggesting at best a small barrier on the exit channel. These observations have led to speculation about the validity of detailed balance in this system. Here we show that this discrepancy can be explained by considering both the surface-molecule co-ordinate and that associated with the Si-Si dimer bond tiltangle. By preparing the surface dimers with a specific tiltangle we demonstrate that the barrier to adsorption is a function of this angle and that the sticking coefficient dramatically increase for certain angles. The adsorption-desopption dynamics can then be described in terms of a common potential energy hypersurface involving both of these co-ordinates. The implications of these observations are also discussed. The dynamics of adsorbed hydrogen atoms on the Si(100) surface is also described. Paired dangling bonds produced following recombinative hydrogen desorption are mobile at elevated temperatures. Pairs of dangling bonds are observed to dissociate, diffuse, and ultimately recombine. At sufficiently elevated temperatures dangling bond exchange reactions are observed. These data are analyzed in terms of an attractive zone and an effective binding interaction between dangling bonds. Insights that this provides into the nature of surface defects and the localized chemistry that occurs on this surface, are also discussed.

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.83-90
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• 2020

This study conducted a risk assessment using the HyKoRAM program created by international joint research. Risk assessment was conducted based on accident scenarios and worst-case scenarios that could occur in the facility, reflecting design specifications of major facilities and components such as compressors, storage tanks, and hydrogen pipes in the hydrogen charging station, and environmental conditions around the demonstration complex. By identifying potential risks of hydrogen charging stations, we are going to derive the worst leakage, fire, explosion, and accident scenarios that can occur in hydrogen storage tanks, treatment facilities, storage facilities, and analyze the possibility of accidents and the effects of damage on human bodies and surrounding facilities to review safety.

• Journal of Hydrogen and New Energy
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• v.34 no.6
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• pp.722-727
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• 2023

There are various types of hydrogen production methods, but among them, the alkaline water electrolysis method produces hydrogen by electrolyzing water, and unlike other methods, it can produce green hydrogen that does not emit pollutants and greenhouse gases. There are many different potential risk factors inherent in the water electrolysis process. So it is necessary to predict an emergency situation in advance and to safely manage and take countermeasures according to the emergency situation. Korea Gas Safety Corporation (KGS) CODE AH271 stipulates legal matters to secure safety, but it is not detalied. Thus it is necessary to take measures to safely control and manage it according to the situation in which an emergency stop is required. In this study, based on KGS CODE and HAZOP for alkaline water electrolysis facilities, factors that can cause emergency situations were derived and countermeasures were prepared.

• Applied Chemistry for Engineering
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• v.25 no.5
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• pp.538-543
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• 2014

In order to substitute for the marketed horseradish peroxidase, a hydrogen peroxide sensor embedded with tobacco leaf in carbon pastes was constructed and its sensing ability was electrochemically evaluated. Ten and more electrode parameters obtained implied that the enzyme electrode exerts its remarkable specificity quantitatively in the experimental range of potential. Especially the small symmetry factor (${\alpha}$, 0.21) showed that the electrode kinetics is very sensitive to the change of electrode potential. The experimental facts above suggested that our enzyme electrode functions as a hydrogen peroxide sensor normally and tobacco peroxidase can be used in the place of the marketed one as an alternative to marketed ones.

• Toxicological Research
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• v.23 no.1
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• pp.25-31
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• 2007

To evaluate the protective effect of Houttuynia cordata on hydrogen peroxide-induced oxidative DNA damage in HepG2 cell line, we used an alkaline single-cell gel electrophoresis (SCGE; comet assay). The DNA damage was analyzed by tail moment (TM) and tail length (TL), which used markers of DNA strand breaks in SCGE. The $100{\mu}g/ml$ of methanolic extract of Houttuynia cordata root showed significant protective effects (p < 0.01) against hydrogen peroxide-induced DNA damage in HepG2 cells and increased cell viability against hydrogen peroxide. The results of this study indicate that Houttuynia cordata root methanol extract acts as a potential antioxidant, and exhibits potential anticancer properties, which may provide a clue to find applications in new pharmaceuticals for oxidative stability.

• Applied Chemistry for Engineering
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• v.4 no.2
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• pp.409-415
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• 1993

A potential function is applied to a hydrogen bonded system such as O-H---O and is slightly modified to provide a good understanding of a range of data. The use of this model requires a knowledge of terms describing the Van der Waals repulsion and the electrostatic interaction and the determination of these terms form the equilibrium conditions is described. Using this simple model, it will be shown that the relationship between the frequency shift and enthalpy of hydrogen bond formation is predicted to be linear and this is in reasonable agreement with experimental results in the literature.

• Bulletin of the Korean Chemical Society
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• v.33 no.6
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• pp.1998-2004
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• 2012

We carried out DFT calculations for monohydrated sulfuric and phosphoric acids. We are interested in clusters which differ in orientation of hydrogen atoms only. Such molecular complexes are close in energy, since they lie in the vicinity of the global minimum energy structure on the flat potential energy surface. For monohydrated sulfuric acid we identified four different isomers. The monohydrated phosphoric acid forms five different conformers. These systems are difficult to study from the theoretical point of view, since binding energy differences in several cases are very small. For each structure, we calculated harmonic vibrational frequencies to be sure that if the optimized structures are at the local or global minima on the potential energy surface. The analysis of calculated -OH vibrational frequencies is useful in interpretation of infrared photodissociation spectroscopy experiments. We employed four different DFT functionals in our calculations. For each structure, we calculated binding energies, thermodynamic properties, and harmonic vibrational frequencies. Our analysis clearly shows that DFT approach is suitable for studying monohydrated inorganic acids with different hydrogen atom orientations. We carried out MP2 calculations with aug-cc-pVDZ basis set for both monohydrated acids. MP2 results serve as a benchmark for DFT calculations.