• The Korean Journal of Physiology and Pharmacology
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• v.16 no.3
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• pp.205-209
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• 2012

The objective of the present study was to establish the method of measurement of hydrogen peroxide and to estimate the anti-oxidative effect of genistein in the skin. UVB induced skin oxidation and anti-oxidative effect of genistein formulations were evaluated by determining levels of hydrogen peroxide. The mechanism involved in the determination of hydrogen peroxide is based on a color reaction between ferric ion ($Fe^{3+}$) and xylenol orange, often called FOX assay and subsequent monitoring of absorbance values of the reactant at 540 nm. The reaction was to some extent pH-dependent and detection sensitivity was greatest at pH 1.75. Genistein liposomal gel demonstrated better anti-oxidative effect with regard to lowering hydrogen peroxide levels elevated by UVB irradiation compared to genistein-suspended gel. A linear relationship has been observed between anti-oxidative effect of genistein and drug deposition in the skin tissue. Genistein liposomal gel resulting in the localization of the drug in the deeper skin led to improved anti-oxidative effect compared to genistein gel. The suggested method for evaluation of oxidation of the skin can be used as a tool to screen effective anti-oxidative agents and their delivery systems acting on the skin.

• Bulletin of the Korean Chemical Society
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• v.26 no.10
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• pp.1611-1613
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• 2005

• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.586-589
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• 2010

In present work, oxidative addition reaction of 1,3-cycleohexandion (1,3-CHD) with ethyl vinyl ether (EVE) was attempted utilizing $Ag_2CO_3$/celite (SC) reagent. In order to optimize reaction conditions, we surveyed several solvents for the production of dihydrofuran with the (SC) system. The yield of the acetonitrile (AN), dimethyl sulfoxide (DMSO), benzene (BZ), and heptane (HT) are given 78, 40, 15, and 10%, respectively. Therefore, we studied the solvent effects on yields by using PM3 and ZINDO/1 parameter of semi-empirical method of HyperChem7.0 molecular modeling program.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1566-1571
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• 2007

Oligodeoxyribonucleotide bearing the di-acetylenic linkage has been prepared. Staring from 5-Iodo-2'-deoxyuridine(1), a four-step sequence, consisting of the Pd(0)-catalyzed Heck-type C-C coupling with acetylenic group, protection of 5'-hydroxy group, generation of acetylenic hydrogen, and Glaser oxidative coupling reaction leads to the dimeric oligodeoxyribonucleotide(5).

• Bulletin of the Korean Chemical Society
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• v.22 no.8
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• pp.909-913
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• 2001

The kinetics of oxidative decarboxylation of pyruvic acid and benzoylformic acid by peroxomonophosphoric acid (PMPA) in aqueous medium have been investigated. The reaction follows second order-first order each in PMPA and substrate concentration a t constant pH. The reactivity of different peroxo species in the oxidation has been determined. Activation energy and thermodynamic parameters have been computed. A plausible mechanism consistent with the observed results is proposed.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.5
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• pp.476-485
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• 2005

In this study, abiotic transformation of TNT reduction products via oxidative-coupling reaction was investigated using Mn oxide. In batch experiments, all the reduction products tested were completely transformed by birnessite, one of natural Mn oxides present in soil. Oxidative-coupling was the major transformation pathway, as confirmed by mass spectrometric analysis. Using observed pseudo-first-order rate constants with respect to birnessite loadings, surface area-normalized specific rate constants, $k_{surf}$, were determined. As expected, $k_{surf}$ of diaminonitrotoluenes (DATs) ($1.49{\sim}1.91\;L/m^2{\cdot}day$) are greater about 2 orders than that of dinitroaminotoluenes (DNTs) ($1.15{\times}10^{-2}{\sim}2.09{\times}10^{-2}\;L/m^2{\cdot}day$) due to the increased number of amine group. In addition, by comparing the value of $k_{surf}$ between DNTs or DATs, amino group on ortho position is likely to be more preferred for the oxidation by birnessite. Although cross-coupling of TNT in the presence of various mediator compounds was found not to be feasible, transformation of TNT by reduction using $Fe^0$ followed by oxidative coupling using Mn oxide was efficient, as evaluated by UV-visible spectrometry.

• Journal of Soil and Groundwater Environment
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• v.12 no.5
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• pp.115-123
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• 2007

Immobilization of contaminants in subsurface environment is one of the major processes that determine their fate. Especially, immobilization by oxidative-coupling reactions, which is irreversible in the bio-chemical reactions and results in a significant reduction of toxicity, can be successfully applied for the remediation of contaminated soil and groundwater more effectively than conventional degradation. As a catalyst of this oxidative-coupling reaction, manganese oxide has many advantages in practical aspects as compared to microorganisms or oxidoreductive enzymes extracted from microorganisms, fungi, or plants. This paper is to present recent research achievements on the treatment mechanisms of various organic contaminants by manganese oxide. Especially, treatment methods of non-reactive organic compounds to Mn oxide are the main focus; i.e., application of reaction mediator, PAHs treatment method, combination with an appropriate pretreatment such as reduction using $Fe^0$, which suggests the potential of a wide range of engineering application. Concerning the natural carbon cycle processes, immobilization and stabilization by oxidative coupling reaction can be effectively applied as a environmentally-friend remediation method especially for aromatic contaminants which possess a high resistance to degradation.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.358-364
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• 2018

An isotropic pitch precursor for fabricating carbon fibres was prepared by co-carbonization of ethylene bottom oil(EBO) and polyvinyl chloride (PVC). Various pre-treatments of EBO and PVC, and a high heating rate of $3^{\circ}C/min$ with no holding time, were evaluated for their effects on the oxidative stabilization process and the mechanical stability of the resulting fibres. Our stabilization process enhanced the volatilization, oxidative reaction and decomposition properties of the precursor pitch, while the addition of PVC both decreased the onset time and accelerated the oxidative reaction. Aliphatic carbon groups played a critical role in stabilization. Microstructural characterization indicated that these were first oxidised to carbon-oxygen single bonds and then converted to carbon-oxygen double bonds. Due to the higher heating rate and lack of a holding step during processing,the resulting thermoplastic fibers did not completely convert to thermoset materials, allowing partially melted, adjacent fibres to fuse. Fiber surfaces were smooth and homogeneous. Of the various methods evaluated herein, carbon fibers derived from pressure-treated EBO and PVC exhibited the highest tensile strength. This work shows that enhancing the naphthenic component of a pitch precursor through the co-carbonization of pre-treated EBO with PVC improves the oxidative properties of the resulting carbon fibers.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.1
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• pp.33-37
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• 2003

Oxidative damage to mitochondria is a critical mechanism in necrotic or apoptotic cell death induced by many kinds of toxic chemicals. Thioredoxin (Trx) family proteins are known to play protective roles in organisms under oxidative stress through redox reaction by using reducing equivalents of cysteines at a conserved active site, Cys-X-X-Cys. Whereas biological and physiological properties of Trx1 are well characterized, significance of mitochondrial thioredoxin (Trx2) is not well known. Therefore, we addressed physiological role of Trx2 in PC12 cells under oxidative stress. In PC12 cells, transiently overexpressed Trx2 significantly reduced cell death induced by hydrogen peroxide, whereas mutant Trx2, having serine residues instead of two cysteine residues at the active site did not. In addition, stably expressed Trx2 protected PC12 cells from serum deprivation. These results suggest that Trx2 may play defensive roles in PC12 cells by reducing oxidative stress to mitochondria.

• Journal of Fashion Business
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• v.9 no.5
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• pp.136-144
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• 2005

Oxidative hair color is currently widely used because of its beautiful light color and good dyeability. In this study, hair color, oxidative agents, and dye intermediate were reacted. Modifier, which changes color with various hue, and alkaline agent, which opens the cuticle of hair fiber and enhances the dyeing reaction, were added. For gel formation, isocetyl alcohol was used as solvent in preparing three kinds of permanent oxidative hair color. Physiochemical study of prepared permanent oxidative hair color was done for basic information acquisition. Acid perspiration test, pH measurement both at room temperature and at high temperature, drop movement test, dyeability efficiency upon the amount of hydrogen peroxide added, and humidity fastness were studied. Shampoo fastness and light fastness of prepared permanent oxidative hair color dyed hair sample were also investigated. All three kinds of hair color prepared showed good properties overall, however, dyed hair sample became reddish upon shampoo fastness and lightfastness tests.