• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.255-255
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• 2011

Zinc oxide based thin films have been extensively studied in recent several years because they have very interesting properties and zinc oxide is non-poisonous, abundant and cheap material. ZnO films are employed in different applications like transparent conductive layers in solar cells, protective coatings and so on. Wide industrial application of the ZnO films requires of development of cheap, effective and scalable technology. Typically used technologies don't completely satisfy the industrial requirements. In the present work, we studied effect of the deposition parameters on the structure and properties of ZnO films deposited by DC arc plasmatron. The varied parameters were gas flow rates, precursor composition, substrate temperature and post-deposition annealing temperature. Vapor of Zinc acetylacetone was used as source materials, oxygen was used as working gas and argon was used as the cathode protective gas and a transport gas for the vapor. The plasmatron power was varied in the range of 700-1500 watts. Flow rate of the gases and substrate temperature rate were varied in the wide range to optimize the properties of the deposited coatings. After deposition films were annealed in the hydrogen atmosphere in the wide range of temperatures. Structure of coatings was investigated using XRD and SEM. Chemical composition was analyzed using x-ray photoelectron spectroscopy. Sheet conductivity was measured by 4-point probe method. Optical properties of the transparent ZnO-based coatings were studied by the spectroscopy. It was shown that deposition by a DC Arc plasmatron can be used for low-cost production of zinc oxide films with good optical and electrical properties. Increasing of the oxygen content in the gas mixture during deposition allow to obtain high-resistive protective and insulation coatings with high adhesion to the metallic surface.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.6
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• pp.748-756
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• 2000

Effects of xanthine (X), xanthine oxidase (XO), and catalase (C), $H_2O_2$, and carbohydrates on sperm capacitation, acrosome reaction, and fertilizing ability in vitro were examined. Glucose alone, but not fructose, supported the maximum rate of sperm capacitation and acrosome reaction. However, in the combination of X, XO, and C (XXOC) or $H_2O_2$, fructose alone also supported maximum capacitation, acrosome reaction, and fertilization. Either insufficient or excessive amounts of $H_2O_2$ decreased sperm capacitation and the acrosome reaction. In order to understand how glucose generates $H_2O_2$ or other reactive oxygen species in sperm cells, 6-aminonicotinamide, an inhibitor of the pentose-phosphate pathway (PPP), and apocynin, an inhibitor of NADPH oxidase, were added to sperm suspensions in glucose-containing medium. Results appeared that sperm capacitation, acrosome reaction, and fertilization were consequently inhibited by either one of these compounds. These inhibitory effects were nullified by addition of XXOC. These results support the hypothesis that glucose, in addition to being a substrate for glycolysis, facilitates sperm capacitation and the acrosome reaction by generating reactive oxygen species through G-6-P dehydrogenase and NADPH oxidase.

• Clinical and Experimental Reproductive Medicine
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• v.45 no.1
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• pp.10-16
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• 2018

Objective: Placental oxidative stress is known to be a factor that contributes to pregnancy failure. The aim of this study was to determine whether selenium could induce antioxidant gene expression and regulate invasive activity and mitochondrial activity in trophoblasts, which are a major cell type of the placenta. Methods: To understand the effects of selenium on trophoblast cells exposed to hypoxia, the viability and invasive activity of trophoblasts were analyzed. The expression of antioxidant enzymes was assessed by reverse-transcription polymerase chain reaction. In addition, the effects of selenium treatment on mitochondrial activity were evaluated in terms of adenosine triphosphate production, mitochondrial membrane potential, and reactive oxygen species levels. Results: Selenium showed positive effects on the viability and migration activity of trophoblast cells when exposed to hypoxia. Interestingly, the increased heme oxygenase 1 expression under hypoxic conditions was decreased by selenium treatment, whereas superoxide dismutase expression was increased in trophoblast cells by selenium treatment for 72 hours, regardless of hypoxia. Selenium-treated trophoblast cells showed increased mitochondrial membrane potential and decreased reactive oxygen species levels under hypoxic conditions for 72 hours. Conclusion: These results will be used as basic data for understanding the mechanism of how trophoblast cells respond to oxidative stress and how selenium promotes the upregulation of related genes and improves the survival rate and invasive ability of trophoblasts through regulating mitochondrial activity. These results suggest that selenium may be used in reproductive medicine for purposes including infertility treatment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.9
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• pp.1330-1335
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• 2005

Red brownish p-pheylenediamine (PPD) has been widely used hair dye for women. The dye was known to cause systemic anaphylaxis, dermatitis and bladder cancer. But the effect of PPD toxicity with oxygen free radical has not been studied. This study investigated the degree of skin injury by PPD. PPD ($2.5\%$ PPD in $2\%\;NH_{4}OH$) was applied to the rat skin ($25 mg/16.5\;cm^2$) 3 or 5 times every other day. Histopathological findings demonstrated the proliferation of epithelial cells and the increased keratinization by PPD. The activities of glucose 6-phosphatase (G6Pase) was decreased and acid phosphatase (ACP) was increased in PPD-applied rat skin. Groups in which PPD was applied 5 times were more damaged than groups applied 3 times. To examine the relationship between tissue damage and oxygen free radicals, effect of PPD on xanthine oxidase (XO) activity was measured and XO activity was more significantly increased in the group treated with PPD 5 times than 3 times. However, reduced glutathione (GSH) content, and the activities of catalase (CAT), super-oxide dismutase (SOD) and glutathione S -transferase (GST) were more decreased in PPD-applied groups than in controls. Even though the activities of XOD was not changed in the group treated with PPD 3 times, the decreased activities of oxygen free radical system and the damaged skin tissue were observed. This result might be caused by the production of toxic PPD metabolites in rat skin. In conclusion, topical PPD application led to skin injury in a dose-dependent manner, probably due to the generation rate of oxygen free radical.

• The Korea Journal of Herbology
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• v.20 no.4
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• pp.121-132
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• 2005

Objectives : Siegesbeckiae Herba's effect on the protection of nerve cells was tested, and the effects were compared between Siegesbeckia glabrescens Makino, the state of which is spica imported from China, and original Korean leaves of it. Methods : After damaging nerve cells by exposing them on NMDA (N-methyl-D-aspartic acid) and KA(kainic acid), Siegesbeckiae Herba's effect on cell death, inhibition rate, glutamate separation, and ROS(reactive oxygen species) production were examined. Results : 1. Siegesbeckiae Herba inhibited the cell death exposed to NMDA. 2. Siegesbeckiae Herba inhibited the amount of glutamate separated from nerve cells exposed to NMDA. 3. Siegesbeckiae Herba inhibited the production of ROS induced by NMDA. 4. Siegesbeckiae Herba did not inhibit the cell death exposed to KA. 5. Chinese Siegesbeckiae Spica had no inhibition effect on cell death. Conclusions : Siegesbeckiae Herba was effective in inhibiting the death of nerve cells exposed to NMDA, and in protecting nerve cells from various damages in nerve cell diseases. Because Chinese Siegesbeckiae Spica did not show such effects, it is necessary to closely examine those effects according to the used parts.

• Journal of Environmental Health Sciences
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• v.22 no.2
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• pp.96-103
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• 1996

The objectives of this study were to examine the biodegradation of phenol using the anaerobic fluidized bed reactor(AFBR). Mixed microorganisms were selected from the anaerobic digestion tank, and could be adapted to high concentration of phenol by increasing the phenol concentration 600-3600 mg/l step by step. The results were summarized as follows: 1. The average removal efficiency of phenol was 90%, decreased by increasing concentration of phenol, and then a shock range was 1200~2400 ppm. 2. The production rate of biogas in overall limits was proportional to the concentration of influent phenol. 3. At steady state, compositions of gases were $CH_4$ 55~60%, $C0_2$ 34~43%, respectively. These were similar to that of the theoretical estimates. 4. The production rates of biogas and methane per the molarity of phenol removed were linearly increased, 56.45 l gas/mol-phenol and 29.20 l $CH_4/mol$-phenol. Using this biogas, the recoverable energy was 269.1 kcal/mol phenol. It was 120.2 kcal/g-COD, transforming into the chemical oxygen demand. 5. The bulk of microorganisms existed in suspended section of fluidized bed with type of biofilm and its concentration was 340 mg/g-media. In conclusion, the anaerobic treatment of pure phenol was possible and its removal efficiency, introducing the AFBR, was successful. Also toxic organic compound such as phenol was biodegradable and was recoverable as resource of energy.

• Journal of Marine Bioscience and Biotechnology
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• v.14 no.2
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• pp.93-101
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• 2022

Hizikia fusiforme, a type of brown algae, is widely used in Asian cuisine. It has been reported to have various pharmacological effects. In this study, the effects of the ethanol extract from H. fusiforme (EAHF) on the proliferation of human colon carcinoma cells were investigated. The effect on the survival of human hepatocarcinoma and colon carcinoma cells was examined, and results revealed that the anti-proliferative effects of EAHF were higher in colon carcinoma cells than in hepatocarcinoma cells. The inhibition of proliferation of HT29 colon carcinoma cells by EAHF treatment was closely related to the induction of apoptosis. EAHF treatment also increased caspase activity and poly(ADP-ribose) polymerase degradation, induced mitochondrial dysfunction, altered Bcl-2 family protein expression, and increased the rate of cytochrome c released from the mitochondria into the cytoplasm. Furthermore, the production of reactive oxygen species (ROS) was markedly stimulated by EAHF treatment, and when ROS production was blocked, EAHF-induced cytotoxicity was significantly attenuated. These results indicate that the anticancer activity of EAHF in HT29 colon carcinoma cells was induced by ROS-dependent mitochondrial impairment. While EAHF exhibited potent anticancer activity in colon carcinoma cells in this study, further studies on the active components of EAHF and their efficacy should be performed.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.4
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• pp.249-255
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• 2009

The performance of microbial fuel cell (MFC) can be affected by many factors including the rate of organic matter oxidation, the electron transfer to electrode by electrochemical bacteria, proton diffusion, the concentration of electron acceptor, the rate of electron acceptor reduction and internal resistance. the performance of MFC using oxygen as electron acceptor can be influenced by oxygen concentration as limit factors in cathode compartment. Many studies have been performed to enhance electricity production from MFC. The series or parallel stacked MFC connected several MFC units can use to increase voltages and currents produced from MFCs. In this study, a single MFC (S-MFC) and a stacked MFC (ST-MFC) using acetate as electron donor and oxygen as electron acceptor were used to investigate the influence of dissolved oxygen (DO) concentrations in cathode compartment on MFC performance. The power density (W/$m^3$) of S-MFC was in order DO 5 > 3 > 7 > 9 mg/L, the maximum power density (W/$m^3$) of S-MFC was 42 W/$m^3$ at DO 5 mg/L. The power density (W/$m^3$) of ST-MFC was in order DO 5 > 7 > 9 > 3 mg/L and the maximum power density (W/$m^3$) of STMFC was 20 W/$m^3$ at DO 5 mg/L. These results suggest that the DO concentration of cathode chamber should be considered as important limit factor of MFC operation and design for stacked MFC as well as single MFC. The results of ST-MFC operation showed the voltage decrease of some MFC units by salt formation on the surface of anode, resulting in decrease total voltage of ST-MFC. Therefore, connecting MFC units in parallel might be more appropriate way than series connections to enhance power production of stacked MFC.

• Reproductive and Developmental Biology
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• v.28 no.2
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• pp.119-126
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• 2004

The present study was carried out to examine the effect of four different media (NCSU (North Carolina State University)-23, PZM (Porcine Zygotes Medium)-3, PZM-4 and TCM (Tissue Culture Medium)-l99) and two oxygen concentrations (39 , 5% $O_2$, 5% $CO_2$ and 90% $N_2$, 5% $CO_2$ in air) on in vitro production of porcine IVM/IVF embryos. The results were summarized as follows: The rates of GVBD and nuclear maturations were not significantly different (p>0.05) for 44 hours of culture with four media in two oxygen concentrations. The rates of polyspermy, penetrated sperm(s) and male and female prouclei formation were not significantly different (p>0.05). among four media in two oxygen concentrations. The cleavage rates were not significantly different (p>0.05) among four media in two oxygen concentrations. At day 7 under gas atmosphere of 5% $O_2$, 5% $CO_2$ and 90% $N_2$, the blastocyst formation was significantly higher (p<0.05) in PZM-3 (19.9$\pm$2.4) than other media. Also, NCSU-23 medium gave high rate of blastocyst formation at day 7 under gas atmosphere of 5% $CO_2$ in air (p<0.05). Based on the result of differential staining of porcine blastocyst at dat 7, inner cell mass cell and total cell numbers were not significantly different (p>0.05) among four media in two oxygen concentrations. However, the observed total cell number was higher in PZM-3 medium (36.8$\pm$6.5) than other madia. In conclusion, these results suggested that in vitro production of porcine embryos in PZM-3 medium under a gas atmosphere of 5% $O_2$, 5% $CO_2$ and 90% $N_2$ was effective on the blastocyst formation rate and total blastocyst cell number.

• Journal of the Korean Professional Engineers Association
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• v.18 no.3
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• pp.28-35
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• 1985

As the paper industry consumes much water in process and discharge wastewater containing suspended solid and COD(chemical oxygen demand), relevant law against this discharge has been set up to limit the total containment of COD in discharge. This study has been carried out to improve the treatment method for the soluble COD in wastewater produced during the process of paste-board production, which is made of semichemical pulp and waste paper. Applicated methods are, O$_2$AS : O$_2$ activated sludge process DAS : Deep well activated sludge process SAS : standard activated sludge process and proper combination of DAS and SAS 1) As a result of this experiment, we get the following conclusion between in COD sludge loading "X" and COD removable rate in the process of treating waste-water. COD removable rate(％)=(0.778+0.0146/X)${\times}$100(％)……(7) 2) In case that the COD sludge loading is high, it has been cleared out that the COD removable rate shall become low due to unknown unsoluble substances contained in the process. Meanwhile, to increase the efficiency rate of treatment, it is thought to be necessary, to provide long-time contacts with activated sludge. 3) Once the COD of original waste-water and the target COD of treated water are decided, COD sludge loading is obtained from equation(7), and capacity of aeration tank in the effective systems such as O$_2$AS, DAS, to bet the required COD removable rate can be decided. Therefore the choice among SAS, O$_2$AS, DAS methods is made in consideration of required COD removable rate and allowable installation area. 4) In the sedimentation tank with sludge bulking, it is possible to increase the COD removable rate by 3～7％ but still there exist many obstacles to manage this operation.