• Journal of Environmental Science International
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• v.24 no.7
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• pp.947-954
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• 2015

Dielectric barrier discharge plasma is a new technique in water pollutant degradation, which that is characterized by the production of chemically active species such as hydroxyl radicals, ozone, hydrogen peroxide, etc. If dissolving of plasma gas generated in the plasma reaction has increased, it is possible to increase the contaminant removal capacity. In this study, the improvement on the dissolving performance of plasma gas was evaluated by the indirect method measuring the overall oxygen transfer coefficient. Experiments were conducted to examine the effects of nozzle type, distance from water surface, air supply rate and liquid circulation rate. The experimental results showed that the $K_{La}$ value of the 3-prong nozzle is 2.67 times higher than the diffuser. The order of $K_{La}$ value with nozzle type ranked in the following order: 3-prong nozzle (inner diameter, less 1 mm) > circular nozzle (inner diameter, 1.5 mm) > ellipse nozzle (short diameter 1 mm, long diameter 2.5 mm) > circular nozzle (inner diameter, 3 mm). Optimal liquid circulation rate was appeared to be 1.7 L/min, the value of $K_{La}$ was 0.510 1/min. The value of $K_{La}$ with increasing air supply rate was revealed in the form of an exponential such as $K_{La}=0.3581e^{0.2919^*air\;flow\;rate}$.

• Journal of Environmental Science International
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• v.25 no.3
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• pp.373-383
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• 2016

The aim of this study is to determine the exposure concentration of tetrabromobisphenol A(TBBPA) in southwestern coast and their photodecomposition rate. Also, it is to identify the radical species of the photodecomposition of TBBPA and their reactive byproducts using the electron spin resonance(ESR) method. TBBPA was not detected in any of the sea water samples from Mokpo, Gunsan, or Goheung. The sediment samples from Mokpo contained not detection(N.D)~50.0 ng/g dry wt., while those from Gunsan contained N.D~28.5 ng/g dry wt. and those from Goheung contained N.D~7.3 ng/g dry wt. The photodecomposition rates were $2.56{\times}10^{-6}/hr$ by visible light(400 nm), $7.98{\times}10^{-6}/hr$ by ultraviolet light(300 nm <), and $6.78{\times}10^{-6}/hr$ by sunlight. Also, we confirmed that singlet oxygen and hydroxyl radicals are the key reactive oxygen species at wavelengths greater than 400 and 300 nm, respectively. This study shows that the main byproducts formed during irradiation at wavelengths above 300 nm are 2,6-dibromobenzosemiquinone radical(2,6-$DBSQ{\cdot}^-$) and g-value 2.0048 doublet spectrum.

• Journal of the East Asian Society of Dietary Life
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• v.5 no.3
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• pp.215-221
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• 1995

This study was undertaken to investigate the effect of Taraxacum herba extract on the hepatic xanthine oxidase activity as a oxygen free radical generating enzyme in vitro and in vivo. It was observed that partial purified hepatic xanthine oxidase (type O) activity was strongly inhibited by the addition of Taraxacum herba n-butanol extract in vitro. The Km value of xanthine oxidase without affecting the Vmax value for xanthine was significantly increased by the addition of ta-dase (type O) activity was significantly inhibited by the treatment of Taraxacum gerba n-butanol ex-tract for 5days(over 40mg/kg, i.p), whereas, xanthine oxidase (type D) activity was not changed by the injection of Taracacum herba n-butanol extract. Meanwhile, liver weight / body weight(%), serum alanine aminotransferase activity and hepatic lipid peroxide content in Taraxacum herba n-buta-nol extract-treated rat were not changed. These findings led us to conclude that Taraxacum herba n-butanol extract may regulate the hepatic xanthine oxidase type O activity to prevent toxic effect of oxidative stress by the oxygen free radicals.

• Journal of Microbiology and Biotechnology
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• v.32 no.12
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• pp.1547-1552
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• 2022

β-Amyrin is a pentacyclic triterpene widely distributed in leaves and stems worldwide. The ability of β-amyrin to induce the production of reactive oxygen species (ROS) in microorganisms suggests its potential as an antimicrobial agent. Thus, this study aimed to elucidate the antibacterial mode of action of β-amyrin. We treated Escherichia coli cells with β-amyrin and found that it triggered ROS accumulation. Excessive stress caused by ROS, particularly hydroxyl radicals, induces glutathione (GSH) dysfunction. GSH protects cells from oxidative and osmotic stresses; thus, its dysfunction leads to membrane depolarization. The resultant change in membrane potential leads to the release of apoptotic proteins, such as caspases. The activated caspases-like protein promotes the cleavage of DNA into single strands, which is a hallmark of apoptosis-like death in bacteria. Apoptotic cells usually undergo events such as DNA fragmentation and phosphatidylserine exposure, differentiating them from necrotic cells, and the cells treated with β-amyrin in this study were positive for annexin V and negative for propidium iodide, indicating apoptosis-like death. In conclusion, our findings suggest that the antibacterial mode of action of β-amyrin involves the induction of ROS, which resulted in apoptosis-like death in E. coli.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.2
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• pp.87-92
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• 2000

This study was designed to investigate the effects og $10{\%},\;20{\%}\;and\;40{\%}$-addition of functional brown algae (FBA)-noodles on oxygen radicals and their scavenger enzymes in liver of Sprague-Dawley(SD) male rats. Hydroxyl radicals$({\cdot}OH)$ formations were significantly inhibited$(20{\~}35{\%}\;and\;12{\~}20{\%})$ in liver mitochondria and microsomes of rats administered $0{\%},\;20{\%}\;and\;40{\%}$ FBA-noodles compared with that of control group. Significant differences in $H_2O_2$ formations of liver microsome in these FBA-noodles fed groups could not be obtained, but superoxide-radical $(O_2^({\cdot}-))$ formations of liver cytosol resulted in a significant decrease about $10{\%}\;in\;20{\%}\;and\;40{\%}$ FBA-noodles compared with control group. Mn-SOD activities in liver mitochondria were significanlty increased $(10{\~}15{\%})$ in the groups fed $10{\%},\;20{\%}\;and\;40{\%}$ FBA-noodles, while a group administered $40{\%}$ FBA-noodle only resulted In a significant increases $(about 12{\%})$ in Mn-SOD activity of liver microsomes compared with control group. Cu, Zn-SOD activities in liver cytosol were significantly increased $(10{\~}20{\%})\;in\;10{\%},\;20{\%}\;and\;40{\%}$ FEA-noodles compared with control group. Administration of $10{\%},\;20{\%}\;and\;40{\%}$ FBA-noodles resulted in a marked increases$(20{\~}40{\%})$ in liver cytosolic glutathione peroxidase (GSHPx) compared with control group. Significant differences in lipid peroxide (LPO) levels of mitochondria and microsomes in $10{\%}$ FBA-noodle could not be obtained, while LPO levels of $20{\%} and 40{\%}$ FBA-noodles were significantly inhibited about $10{\%}$ in mitochondria and microsomes compared with control group. These results suggest that these FBA-noodles may play a desirable role in attenuating an oxygen radical formations and increasing a scavenger enzymes activity by some brown algae (Undaria pinnatifida) components.

• Journal of Life Science
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• v.7 no.1
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• pp.10-16
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• 1997

This study was designed as a part of efforts to investigate the biochemical pollutant markers for diagnosis of marine pollutions by changes in oxygen radicals and their scavenger enzymes of the flounder (Paralichthys olivaceus)in Yellow Sea of Kores. Protein contents in brian and muscle of cultured flounder in Yellow Sea were remarkably lower(30-45% and 25-45%, respectively) than those of wild flounders in Pohang(control) of East Sea. Lipid peroxide(LPO) levels in serum of cultured and wild flounders in Yellow Sea were significanltly higher (30-80% and 125-145%, respectively)than those of wild flounder in Pohang. Hydroxide radical formations and superoxide dismutase(SOD) activities in serum of cultured flounders in Yellow Sea were significantly 15-30% and 15-35% lower than those of wild flounders in Pohang, but glutathione peroxidase (GSHPx) activities in brain of cultured flounders in Yellow Sea were significantly 15-25% higher than those of wild flounders in Pohang. It is believed that significantly decreases of protein contents in brain anad muscle, remakable increases of malondialdehyde(LPO) in serum and glutathione peroxidase (GSHPx)in brain of cultured flounders of Yellow Sea may be used as a biochemical pollutant markers for diagnosis of marine pollutions.

• Journal of Oriental Physiology
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• v.14 no.2 s.20
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• pp.199-208
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• 1999

As the average life span have been lengthened and the rate of senile population have been raised, chronic degenerative diseases incident to aging has been increased rapidly and become a social problem. With this social background, recently, the facts that oxygen radicals(OR) have toxic effects on Central Nervous System and Peripheral Nervous System and cause neuropathy such as Parkinson's Disease, Alzheimer Disease have been turned out, and accordingly lots of studies on the mechanism of the toxic effects of OR on nerves, the diseases caused by OR and the approaches to curing the diseases have been made. The purpose of this study is to examine the toxic effects caused by Glucose Oxidase(GO) and the effects of herbal extracts such as Chilbokyeum(CBY) on the treatment of the toxic effects. For this purpose, experiments with the cultured cell from the cerebrums of new born mice were done. The results of these experiments were as follows. 1. GO, a oxygen radical, decreased the survival rate of the cultured cells on NR assay and MTT assay 2. GO, a oxygen radical, increased lipid peroxidation and the amount of LDH. 3. CBY have efficacy of decreasing lipid peroxidation. 4. CBY have efficacy of decreasing the amount of LOH. From the above results, It is concluded that Chilbokyeum has marked efficacy as a treatment for the damages caused in the GO-mediated oxidative process. And Chilbokyeum is thought to have certain pharmacological effects on controlling over aging and treating Dementia. Further clinical study of this pharmacological effects of Chilbokyeum should be complemented.

• Journal of Photoscience
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• v.9 no.2
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• pp.385-387
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• 2002

Direct EPR evidence of the photo-generation of superoxide radicals ( $O_2$$^{-.}$) was obtained by using spin trapping techniques in spinach photosystem II (PSII) membranes. $O_2$$^{-.}$ was detected by following the formation of 5-diethoxyphosphoryl-5-methyl-1 -pyrroline-N-oxide (DEPMPO) superoxide adducts, DEPMPO-OOH. The significant increase of the EPR signal amplitude of DEPMPO-OOH in N$H_2O$H-, CaC $l_2$- and NaCl-treated PSII membranes showed that the oxygen-evolving system has a close relation to the $O_2$$^{-.}$ production. PSII membranes with inactivated donor side could not prevent the $O_2$$^{-.}$ production efficiently. Treatments on PSII donor side also influence the maximum level and the kinetics of Chlorophyll (Chi) a fluorescence. Results suggested that manganese cluster and extrinsic proteins might affect Chi a fluorescence in ways different from that happens at the acceptor side of PSII.SII.SII.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.664-668
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• 2002

Antioxidants either scavenge superoxide and free radicals or stimulate the detoxification mechanisms within cells, resulting in increased detoxification of free radicals formation. Hyperin, isolated from the stem of Uncaria rhynchophylla, prevented oxygen radical formation and inhibited lipid oxidation. The effective concentrations were 31.3 $\mu$M for a radical scavenging assay and 2.2 $\mu$M for a microsome assay. cDNA microarray analysis to determine which genes were modulated by hyperin found that 50 genes were upregulated and 37 genes were downregulated in SNU-668 human gastric cancer cells. Among these genes, thirteen genes that were significantly affected by hyperin were verified by RT-PCR for their effect of genetic reprogramming.

• Toxicological Research
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• v.11 no.1
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• pp.57-62
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• 1995

To investigate the ultrastructural changes of kidney and clarify to a cause of its changes in lead intoxicated rats, the 0.5% lead acetate administed orally to the rats and those were sacrifled at 2 day, 1, 2, 4, 6 and 8 week after the treatment of lead acetate. Each extirpated kidney was histopathologically examined under the electron microscopy and histochemical examination was also carried out. Concomitantly, the activity of free radical metabolizing enzyme was determined. The blood levels of lead concentration showed a gradual increase from the first group reaching the plateau at the one or two week group with the slightly decreasing value throughout the whole course of the experiment. And the urinary ALA concentration showed a gradual increase from the first group to the 8 week group. In the kidney tissue of rat sacrified at 6 week, the proximal tubular cells showed dilatation of endoplasmic reticulum, mitochondrial swelling, increased numbers of secondary lysosomes and myelin figure-like residual bodies on electron microscope and oxygen free radicals are identified by histochemistry on light microscope whereas there were no differences in the activity of catalase and glutathione peroxidase between the lead acetate treated group and control group. But the activity of xanthine oxidase was more increased in lead acetate treated rats than control group. Furthermore, the superoxide dismutase activity was significantly increased in the experimental group than the control group. In conclusion, it is assumed the kidney damage in lead intoxicated rat may be induced by free radicals.