• The Korean Journal of Physiology and Pharmacology
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• v.13 no.3
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• pp.139-145
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• 2009

The purpose of this study was to evaluate the effects of the water extract of Samultang (SMT), a Chinese herb, on apoptotic cell death by $H_2O_2$-induced oxidative stress in SK-N-M C cells. A nuclear fragmentation was observed via fluorescence imaging 12 h after exposure to 30 ${\mu}M$ $H_2O_2$ and DNA laddering was detected via agarose electrophoresis gel. In addition, increases in sub-G1 phase and cleavage of the PARP protein were observed. However, treatment with SMT for 2 h prior to $H_2O_2$ exposure significantly reduced apoptotic cell death induced by incubation with 30 ${\mu}M$ $H_2O_2$ in SK-N-MC cells. Pre-incubation with water extract of SMT for 2 h prevented the $H_2O_2$-induced decrease in mitochondrial transmembrane potential. SMT also attenuated the increase in caspase-3 activity and the breakdown of PARP protein caused by $H_2O_2$-induced oxidative stress. These results suggest that the water extract of SMT provides inhibition of apoptotic cell death against oxidative injury in SK-N-MC cells.

• Journal of the Korean Chemical Society
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• v.18 no.3
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• pp.157-170
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• 1974

The effects of ionic strength on the polynucleation reaction of tungstate ions and the protonized reaction of polytungstate ions have been investigated in the range of ionic strength from 1 M to 4 M KCl.The hexatungstate ions and the protonized forms of hexatungstate ions are formed in the tungstate solutions whose ionic strengths are 1 M to 4 M KCl. The equilibrium constants for the formation of hexatungstate ions and the protonized forms of hexatungstate ions are calculated in the range of ionic strength from 1 M to 4M KCl. The enthalpy changes for the formation of hexatungstate ions and the protonized forms of hexatungstate ions are as follows; $7H^++{6WO_4}^{2-}={HW_6O_{21}}^{5-}+3H_2O\;\;{\Delta}H^{\circ}=-62.4{\pm}0.6$$H^++{HW_6O_{21}}^{5-}={H_2W_6O_{21}}^{4-}\;\;{\Delta}H+_1^{\circ}=-4.12{\pm}0.10$$H^++{H_2W_6O_{21}}^{4-}={ H_3W_6O_{21}}^{3-}\;\;{\Delta}H_2^{\circ}=-4.36{\pm}0.30$ The free energy and entropy changes for the above reactions have been also calculated. A linear relation is formed between $log k_{6,7}$ and ionic strength, and $log k_1\;or\;log k_2\;vs{\cdot}{\mu}.$ $log k_{6,7}\;=\;D{\mu}+I,\;\;where\;D\;=\;1.66{\pm}0.02$$log k_1\;=\;D_1{\mu}+I_1,\;\;where\;D_1\;=\;-8.065{\pm}0.001$$log k_2\;=\;D_2{\mu}+I_2,\;\;where\;D_2\;=\;-0.376{\pm}0.006$

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.541-547
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• 2011

Nanorod-clustered $MnO_2$ precursors with ${\alpha}$-, ${\beta}$-, and ${\gamma}$-phases are synthesized by hydrothermal reaction of $MnSO_45H_2O$ and $(NH_4)S_2O_8$. The formation of nanorod-clustered ${\beta}-MnO_2$ is particularly confirmed under the conditions of high reactant concentration and hydrothermal reaction at $150^{\circ}C$. The spinel $LiMn_2O_4$ nanorod-clusters are also prepared by lithiating the $MnO_2$ precursors, varying the concentration of lithiating agent ($LiC_3H_3O_2{\cdot}2H_2O$) and heat treatment temperature, and characterized for use as cathode material of lithium-ion batteries. As a result, the nanorod-clustered $LiMn_2O_4$ prepared from the ${\beta}-MnO_2$ at higher $LiC_3H_3O_2{\cdot}2H_2O$ concentration and the annealing at $800^{\circ}C$ is proven to show the cubic spinel structure and to achieve the high initial discharge capacity of 120 mAh/g.

• Journal of the Korean Chemical Society
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• v.24 no.3
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• pp.218-224
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• 1980

The surface reactions of CO and $C_2H_4$ with adsorbed oxygen on ZnO were studied by means of EPR spectroscopy. The EPR spectra of $O_2$ adsorbed ZnO at various temperatures were compared, and the signal at g = 2.014 was characterized as trapped $O^-$ at oxygen vacancy. CO and $C_2H_4$ react with $O^-$ at $25^{\circ}C$ and desorbed as $CO_2$ and $H_2O$ above $200^{\circ}C$. $O_2^-$ species interact with $C_2H_4$ about $100^{\circ}C$, but desorption of partial oxidation products also was not observed until the temperature was raised to $200^{\circ}C$.

• Journal of Hydrogen and New Energy
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• v.9 no.2
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• pp.77-84
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• 1998

Hydrogen isotope exchange in mixtures of $H_2O/D_2$, $H_2O/D_2O$, or $D_2O/H_2$ can be facilitated under electrical discharge. For example, a simple DC corona discharge through the mixture creates a plasma in which the reactants are excited energetically. The reactants in such plasma, due to increase in population of excited quantum levels or due to production of radicals or ions, undergo very rapid chemical reactions even at ambient temperature. The isotope exchange reaction of hydrogen(H) and deuterium(D) produces the third kind of heavy water(HDO) and isotopic hydrogen gas(HD), as shown in $D_2+H_2O{\rightarrow}HD$ K=11.257(at $25^{\circ}C$) The reaction products can be detected with temporal resolution using the Fourier transform infrared(FTIR) absorption spectroscopy. Since $H_2O$, $D_2O$ and HDO are all infrared active with different absorption peaks, FTIR proves to be a useful tool for monitoring the reaction. Experimental results show that the electrical method is indeed a useful means to promote the reaction, showing a better efficiency than traditional catalytic methods.

• Journal of the Korean Ceramic Society
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• v.37 no.1
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• pp.1-5
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• 2000

Cathodoluminescence(CL) properties of ZnO:Zn green phosphor were investigated. ZnO:Zn phosphor was synthesized by varying reducing agents and firing temperatures. ZnS, charcoal and 5% H2 gas mixed with 95% N2 gas(5H2-95N2) were used as the reducing agent and atmosphere. The highest CL intensity of ZnO:Zn phosphor was observed under the condition of 5H2-95N2 atmosphere and firing temperature of 90$0^{\circ}C$ for 1h. Charocal and ZnO as reducing agents in the syntehsis of ZnO:Zn phosphor exhibited about 60% and 40%, respectively, of the CL intensity obtained with 5H2-95N2 atmosphere.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.964-972
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• 2011

This work investigated the difference between $Fe^{2+}$ autoxidation-induced and Fenton-type cleavage of pBR322 plasmid DNA. $^{\cdot}OH$ generation reactions in the absence and presence of $H_2O_2$ under various conditions were also investigated. Although both the $Fe^{2+}$ autoxidation and Fenton-type reactions showed DNA cleavage and $^{\cdot}OH$ generation, there were significant differences in their efficiencies and reaction rates. The rate and efficiency of the cleavage reaction were higher in the absence of 1.0 mM of $H_2O_2$ than in its presence in 20 mM phosphate buffer. In contrast, the $^{\cdot}OH$ generation reaction was more prominent in the presence of $H_2O_2$ and showed a pH-independent, fast initial reaction rate, but the rate was decreased in the absence of $H_2O_2$ at across the entire tested pH range. Studies using radical scavengers on DNA cleavage and $^{\cdot}OH$ generation reactions in both the absence and presence of $H_2O_2$ confirmed that both reactions spontaneously involved the active oxygen species $^{\cdot}OH$, ${O_2}^{\cdot-}$, $^1O_2$ and $H_2O_2$, indicating that a similar process may participate in both reactions. Based on the above observations, a new mechanism for the $Fe^{2+}$ autoxidation-induced DNA cleavage reaction is proposed.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.666-672
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• 2011

The catalytic activity of an inorganic-organic complex with a vanadium-substituted polyoxometalate 1, formulated as [Cu(2,2'-bipy)]$[Cu(2,2'-bipy)_2]_2[PMo_8V_6O_{42}]{\cdot}1.5H_2O$ was studied in the Biginelli reactions. The obtained results showed that, in the one-pot synthesis of dihydropyrimidinones, the turnover frequencies (TOF) for the [Cu(2,2'-bipy)]$[Cu(2,2'-bipy)_2]_2[PMo_8V_6O_{42}]{\cdot}1.5H_2O$ catalyst were higher than the $H_3PMo_{12}O_{40}$ catalyst.

• Journal of Periodontal and Implant Science
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• v.38 no.4
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• pp.645-656
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• 2008

Purpose: To evaulate the effects of chlorhexidine and $H_2O_2$ on matrix metalloproteinase-1 (MMP-1), tissue inhibitor of metalloproteinase(TIMP-1, TIMP-2), Type 1 collagen, fibronectin and UNCL expressions in human periodontal ligament fibroblasts (hPDLF). Materials and Methods: $1.2{\times}10^{-1}%$, $1.2{\times}10^{-2}%$ and $1.2{\times}10^{-3}%$ CHX and $3{\times}10^{-3}%$, $3{\times}10^{-4}%$ and $3{\times}10^{-5}%$ $H_2O_2$ and mixture of CHX and $H_2O_2$ were applied to hPDLF for 1 min and 30 min. The mRNA expressions of MMP-1, TIMP-1 and 2, Type 1 collagen, fibronectin and UNCL in hPDLF were analysed by RT-PCR. Results: The result were as follows: 1. The expression of UNCL mRNA was higher than that of other mRNAs. 2. $1.2{\times}10^{-3}%$ CHX increased mRNA expressions of hPDLF as application time increased. 3. $H_2O_2$ lower than $3{\times}10^{-3}%$ increased expression of UNCL mRNA, and did not decrease mRNA expression of hPDLF. 4. hPDLF treatment with $1.2{\times}10^{-1}%$ CHX (with or without $H_2O_2$) resulted in no gene expression. 5. hPDLF treatment with $1.2{\times}10^{-2}%$ CHX (with or without $H_2O_2$) for 30 minutes resulted in no gene expression. Conclusion: Because low concentration of CHX and $H_2O_2$ increased UNCL mRNA expression of hPDLF, low concentraction of CHX and $H_2O_2$ may have an antioxidative effect.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.3
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• pp.294-305
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• 1994

The influence of deposition parameter on the electrical, optical andsurface morphology of $SnO_2(:F)$ films prepared by ultrasonic spray deposition using DBDA and $SnCl_4.5H_2O$ as a source material was studied. Resistivity was decreased sharply with increasing F/Sn ratio in solution up to 0.6. Depending on the source material, $SnCl_4.5H_2O$ shows lower resistivity than DBDA. When F/Sn ratio in solution was 1, optical transmittance was higher DBDA than $SnCl_4.5H_2O$.