• The Journal of Korean Medicine
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• v.19 no.2
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• pp.373-390
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• 1998

35 theses conducted in Korea on the topic of senescence or anti-oxidant were classified on the basis of research methods, animals used for the experiments, and research items. Evaluating these research works with respect to the Free Radical Theory, the following conclusions were reached. 1. Of the 17 theses written in the Oriental medicine aspect, three theses used a single herb, nine theses used a complex prescription, four theses concentrated on the usage of the medicinal acupuncture, and one research paper focused on using scientific components. Common objection of these papers were on the verification of the efficacy of herbs. 2. Of the 18 these written in the Western medicine aspect, five theses used a single drug, seven theses conducted a research on the changes due to senescence, and 6 papers were on variety of topics. The main focus of these works were on the mechanism and pathology related to the senescence rather than on the suppression of senescence. 3. Among the theses written in the Oriental medicine perspective, a total of 48 herbs were utilized. 26 of these herbs has a tonification function on the Kidney. Six out of nine complex prescription mentioned above has a function of tonifying the Kidney. 4. With respect to the research subjects used on the experiments, 8 theses have used Senescence-Accelerated mice, 13 theses have used Sprague-Dawley mice, and remaining 7 papers have used human or other animals. 5. These are the categorization of the research items used: the weight (11) and weight changes of the visceral organs (9), the measurement of the content of peroxide-disease (9), the measurement of enzyme vitality (21), the blood and urine test (10), the experiment concerning immune system (3), the influence on the hepatic capability of metabolizing foreign substance (3), the effect on hepatic cell protection (3), the measurement of both the suppression of Free Radical and ability to create Free Radical (2), the measurement of effect of suppresing MDA(malondialdehyde) (4), the effect of eliminating DPPH Radical (2), and experiements about the functions (2). 6. The rate of vitalization of well known anti-oxidants such as Superoxide dismutase (SOD), Protein-bound SH, Nonprotein-bound SH, Glutathione(GSH), Catalase, and etc. were tested in 17 theses. Considering the conclusions mentioned above, the theses related to the senescence published in Korea elected different animals used for experiments, research items and the methods of research, the end result seems to be a lack of objectivity. Thus, I would argue that research methods to overcome such a deficiency need to be developed systematically.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.10
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• pp.1418-1424
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• 2010

This study was performed to assess the antioxidant activities and whitening effects of Sorbus commixta HEDL cortex on melanin synthesis. The whitening effects of Sorbus commixta HEDL cortex water extracts were examined by in vitro mushroom tyrosinase assay and B16BL6 melanoma cells. We assessed inhibitory effects of Sorbus commixta HEDL cortex water extracts on expression of melanogenic enzyme proteins including tyrosinase, tyrosinase-related protein 1 (TRP-1) and tyrosinase-related protein 2 (TRP-2) in B16BL6 cells. Inhibitory effects of Sorbus commixta HEDL cortex onto free radical generation were determined by measuring DPPH and hydroxyl radical scavenging activities. Our results indicated that Sorbus commixta HEDL cortex water extracts effectively inhibited free radical generation. In DPPH radical scavenging activity, Sorbus commixta HEDL cortex water extracts had a potent anti-oxidant activity in a dose-dependent manner. They significantly inhibited tyrosinase activity in vitro and in B16BL6 melanoma cells. Also, Sorbus commixta HEDL cortex suppressed the expression of tyrosinase, TRP-1 and TRP-2 in B16BL6 melanoma cells. These results show that Sorbus commixta HEDL cortex inhibited melanin production on the melanogenesis. The underlying mechanism of Sorbus commixta HEDL cortex on whitening activity may be due to the inhibition of tyrosinase activity and tyrosinase, TRP-1, TRP-2 expression. We suggest that Sorbus commixta HEDL cortex may be contain new natural active ingredients for antioxidant and whitening cosmetics.

• Journal of Environmental Science International
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• v.14 no.2
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• pp.231-240
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• 2005

The number of cases exceeding environmental standards of atmospheric ozone in the major cities in Korea has steadily increased during the past decades. In order to understand and analyze the atmospheric reactions in the atmosphere, especially the secondary photochemical reactions, smog chambers studies have been performed very actively by many research groups worldwide. However, these studies have focused on the mechanism of photochemical reactions in high concentration conditions, not at the ambient levels. Therefore, in-depth studies in these conditions are essentially needed to realize exact mechanism in the atmosphere near the earth surface, especially at Korean atmospheric conditions. In this experiment, the mechanism of photochemical smog was examined through a comparative experiment of smog chambers under sun light and black light conditions. The results of our study indicated that concentrations of ozone, aldehyde, and PAN increased as the radiation of light source increases. Photochemical reaction patterns can be considered quite similar for both black light and sun light experiments. Based on our experiments using toluene as a reactant which is present at significant high levels in ambient air relative to other VOCs, it was found that toluene could contribute notably to oxidize NO to $NO_2$, this reaction can eventually generate some other photochemical oxidants such as ozone, aldehyde, and PAN. The results of simulation and experiments generally showed a good agreement quite well except for the case of $O_3$. The restriction of oxidization of NO to $NO_2$ seems to cause this difference, which is mainly from the reaction of peroxy radical itself and other reactants in the real gas.

• Journal of the Korean Chemical Society
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• v.19 no.5
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• pp.367-374
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• 1975

Glycine residue in N-X-glycylphenylalanine methyl ester(X = trifluoroacetyl or acetyl) was converted into aspartic acid derivative by a photoalkylation reaction. The reaction was induced with 350 nm lamp using a combination of diacetyl/di-t-butyl peroxide (DBP) as the photoinitiator, and acetic anhydride as the alkylating agent. In the thermal reaction with DBP and acetic anhydride, the same alkylation reaction of the dipeptide was observed. From this thermal alkylation reaction the photoalkylation reaction is also thought to undergo via free radical mechanism.

• Textile Coloration and Finishing
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• v.11 no.6
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• pp.36-42
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• 1999

The antimicrobial activities of the copolymer of N,N'-dimethyl- N,N'-diallyl ammonium chloride(DMDAAC) and diallyl amino(DA) were investigated. The copolymer of DMDAAC and DA was prepared by free radical Polymerization through an intra-intermolecular propagation mechanism ie, cyclopolymerization. The copolymer was, then, reacted with cyanuric chloride for reactivity with hydroxyl group of cellulose. Cotton fabrics were finished by synthesized polymer, and their antimicrobial activities and fastness to launderings were tested. Dichlorotriazinyl DMDAAC-DA copolymer has MIC value of 1ppm against S. aureus and 10ppm against K pneumoniae. The antimicrobial fastness of the finished cotton to launderings were good enough to show colony reduction above 70% against S. aureus and K pneumoniae after 50 repeated laundering in anionic commercial detergent. Optimum treatment concentrations of the polymer were 0.5% in cold pad-batch method, and 0.1% in pad-dry method.

• Mass Spectrometry Letters
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• v.8 no.1
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• pp.1-7
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• 2017

Studies performed on heterogeneous reactions of hydroxyl radicals (OH) in aerosol materials of tropospheric interest are presented, focusing on the chemical ionization mass spectrometric approach. Kinetic investigations of these reactions reduced deviation in the estimation of OH concentration in the troposphere by atmospheric modeling from field measurements. Recently, OH uptake was investigated under wet conditions to acquire kinetic information under more realistic conditions representative of the troposphere. The information on the mechanism and kinetics of OH uptake by tropospheric aerosol materials will contribute to the updating of atmospheric models, allowing a better understanding of the troposphere.

• Textile Coloration and Finishing
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• v.10 no.6
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• pp.49-54
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• 1998

The antimicrobial activities of the copolymer of N,N'-dimethyl-N,N'-diallyl ammonium chloride (DMDAAC) and acrylamide(AA) were investigated. A series of copolymers with various ratios of DMDAAC and AA were prepared by free radical initiation via an intra-intermolecular propagation mechanism, ie, cyclopolymerization, and the antimicrobial activities of the prepared copolymers were measured by minimum inhibitory concentration(MIC) test. The copolymers were, then, methylolated under basic condition for reactivity with hydroxyl group of cellulose. Both antimicrobial activity and fastness to laundering of the cotton fabrics finished using the methylolated copolymers were evaluated. From the results it was shown that the copolymers with different ratios of DMDAAC and AA have MIC values in the range of 1∼100ppm. As the ratio of AA in the copolymers increases, the anitmicrobial activity decreases. The fastness of the cotton fabric finished by the methyolated copolymers to 10 repeated launderings in anionic commercial detergent is good enough to show colony reduction above 90％ regardless of DMDAAC and AA ratios.

• BMB Reports
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• v.39 no.3
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• pp.335-338
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• 2006

Methylglyoxal (MG) is an endogenous physiological metabolite which is present in increased concentrations in diabetics. MG reacts with the amino acids of proteins to form advanced glycation end products. In this in vitro study, we investigated the effect of MG on the structure and function of ceruloplasmin (CP) a serum oxidase carrier of copper ions in the human. When CP was incubated with MG, the protein showed increased electrophoretic mobility which represented the aggregates at a high concentration of MG (100 mM). MG-mediated CP aggregation led to the loss of enzymatic activity and the release of copper ions from the protein. Radical scavengers and copper ion chelators significantly prevented CP aggregation. CP is an important protein that circulates in plasma as a major copper transport protein. It is suggested that oxidative damage of CP by MG may induce perturbations of the copper transport system and subsequently lead to harmful intracellular condition. The proposed mechanism, in part, may provide an explanation for the deterioration of organs in the diabetic patient.

• Journal of the Korean Society of Combustion
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• v.15 no.4
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• pp.9-14
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• 2010

Numerical simulations of freely propagating fuel-rich $CH_4/CH_3Cl$ premixed flames were performed at atmospheric pressure in order to understand the effect of the oxygen enrichment on the production of PAH. A chemical kinetic mechanism was used, which involved 157 gas-phase species and 1693 forward reactions. The calculated flame speeds were compared with the experiments for the flames established on the equivalence ratios of 1~1.6, the results of which were in good agreement. As the level of oxygen enrichment was increased, the concentrations of one or four ring aromatic hydrocarbons were decreased. This might cause the fact that the contribution of PAH species to soot was weakened.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.10
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• pp.821-827
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• 2001

In this study performed to identify a degradation mechanism in macromolecular insulating material, the contact angel, surface potential decay, surface resistivity, and XPS analysis were compared after exposure of FRP laminate to plasma discharge. In the case of contact angle, the surface of specimen untreated showed weak hydrophobic property of 73。. However, the contact angle was decreased to 20。in the plasma-treated specimen. In the case of chemical changes arising form plasma treatment, carboxl radicals were generated mainly in the surface treated, which was rapidly changed to the hydrophilic one. In the corona potential decay study to determine the electrical changes of the surface, positive charges were rapidly decreased when compared with negative charges, leading to negative property in the surface of specimen not treated. However, in the case of the hydrophilic surface, lots of carboxl radicals acting as positive polarity were generated, resulting in positive surface. Owing to such positive surface, charges of negative polarity applied were rapidly decreased.