• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.28 no.1
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• pp.61-79
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• 2018

Objectives: The objective of this study was to examine the effect of non-thermal dielectric barrier discharge(DBD) plasma on decontamination of Staphylococcus aureus(S. aureus) and Escherichia coli(E. coli) as common pathogens. Methods: This experiment was carried out in a chamber($0.64m^3$)designed by the authors. The plasma was continuously generated by a non-thermal DBD plasma generator(Model TB-300, Shinyoung Air tech, Korea). Suspensions of S. aureus and E. coli of 0.5 McFarland standard($1.5{\times}10^8CFU/mL$) were prepared using a Densi-Check photometer(bio $M{\acute{e}}rieux$, France). The suspensions were diluted1:1000 in sterile PBS solutions(approximately$10^{4-5}CFU/mL$) and inoculated on tryptic soy agar(TSA) in Petri dishes. The Petri dishes(80mm internal diameter)were exposed to the non -thermal DBD plasma in the chamber. Results: The results showed that 95% of S. aureus colonies were killed after a six-hour exposure to the DBD plasma. In the case of E. coli, it took two hours to kill 100% of the colonies. The gram-negative E. coli had a greater reduction than the gram-positive S. aureus. This difference may be due to the structure of their cell membranes. The thickness of gram-positive bacteria is greater than that of gram-negative bacteria. The S. aureus is more resistant to DBD plasma exposures than is E. coli. It should be noted that average concentrations of ozone, a byproduct of the DBD plasma generator, were monitored throughout the experiment and the results were well below the criteria, 50 ppb, recommended by the Korean Ministry of the Environment. Thus, non-thermal DBD plasma is deemed safe for use in hospital and public facilities. Conclusions: There was evidence that non-thermal DBD plasma can effectively kill S. aureus and E. coli. The results indicate that DBD plasma technology can greatly contribute to the control of infections in hospitals and other public and private facilities.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.6
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• pp.910-916
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• 2022

The purpose of this study is to evaluate the effect of underwater non-thermal dielectric barrier discharge plasma (DBD plasma) on the sterilization of three types of pathogenic bacteria that cause diseases in freshwater fish and the reduction of a tetracycline antibiotics. This experiment was conducted in the DBD plasma generator, and the voltages used to generate plasma were 11.6 kV and 23.1 kV. The measurement intervals were 0, 1, 5, 10 and 15 min. As a result of DBD plasma treatment, Aeromonas hydrophila, Edwardsiella tarda and Pseudomonas fluorescens were removed 93-99% after 5 min at 23.1 kV, and the tetracycline antibiotics were reduced 70-95% after 15 min at 23.1 kV. In this study, as a result of treating the effluent with DBD plasma at a fish farm where the medicinal bath was conducted with oxytetracycline-HCl (OTC-HCl) products, OTC-HCl decreased by 62% after 10 min at 23.1 kV.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.2
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• pp.157-165
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• 2003

A combined process of non-thermal plasma and catalytic technique has been investigated to treat $CH_3$CN gas in the atmosphere. A planar type dielectric barrier discharge (DBD) reactor has been used to generate the non-thermal plasma that produces various chemically active species, such as O, N, OH, $O_3$, ion, electrons, etc. Several different types of the beads. which are Molecular Sieve (MS) 5A, MS 13X, Pt/alumina beads, are packed into the DBD reactor, and have been tested to characterize the effects of adsorption and catalytic process on treating the $CH_3$CN gas in the DBD reactor. The test results showed that the operating power consumption and the amounts of the by-products of the non-thermal plasma process can be reduced by the assistance of the adsorption and catalytic process.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.6
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• pp.727-733
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• 2007

In this study, a newly developed biotrickling system, combined with a non-thermal plasma reactor, was investigated to effectively treat gaseous contaminants such as VOCs (Volatile Organic Compounds). Three kinds of non-thermal plasmas (NTPs) such as a rod type dielectric barrier discharge (DBD) plasma, a packed bead type DBD plasma and a gliding arc (GA) plasma, were tested and compared in terms of power consumption. The rod type DBD plasma was selected as one for integration with biotrickling system due to its relatively high VOC removal efficiency, low power consumption and low pressure drop. Toluene and xylene as representatives of VOCs were used as test gases. The experiment results showed that the efficiency of biotrickling system was especially very low at the high gas concentration and high flow rate and the removal efficiencies of VOCs were considerably enhanced in the biotrickling system, when the DBD plasma was worked in front of that even at the high gas concentration and high flow rate.

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.641-650
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• 2022

The purpose of this study was to compare the efficiency of air and oxygen injected into the underwater non-thermal dielectric barrier discharge plasma (DBD plasma) device used to remove five types of antibiotics (tetracycline, doxycycline, oxytetracycline, clindamycin, and erythromycin) artificially contained in the fish farm discharge water. The voltage given to generate DBD plasma was 27.8 kV, and the measurement intervals were 0, 0.5, 1, 2, 4, 8, 16 and 32 minutes. Tetracycline antibiotics significantly decreased in 4 minutes when air was injected and were reduced in 30 seconds when oxygen was injected. After the introduction of air and oxygen at 32 minutes, 78.1% and 95.8% of tetracycline were removed, 77.1% and 96.3% of doxycycline were removed, and 77.1% and 95.5% of oxytetracycline were removed, respectively. In air and oxygen, 59.6% and 83.0% of clindamycin and 53.3% and 74.3% of erythromycin were removed, respectively. The two antibiotics showed lower removal efficiency than tetracyclines. In conclusion, fish farm discharge water contains five different types of antibiotics that can be reduced using underwater DBD plasma, and oxygen gas injection outperformed air in terms of removal efficiency.

• KSBB Journal
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• v.30 no.1
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• pp.21-26
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• 2015

Plasma is an ionized gas mixture, consisting of neutral particles, positive ions, negative electrons, electronically excited atoms and molecules, radicals, UV photons, and various reactive species. Also, plasma has unique physical properties distinct from gases, liquids, and solids. Until now, non-thermal plasmas have been widely utilized in bio-medical applications (called bio-plasma) and have been developed for the plasma-related devices that are used in the medical field. Although numerous bio-plasma studies have been performed in biomedicine, there is no confirmation of the nonthermal effect induced by bio-plasma. Standardization of the biological application of plasma has not been evaluated at the molecular level in living cells. In this context, we investigated the biological effect of bio-plasma on living cells. Hence, we treated the fibroblasts with Dielectric Bauvier Discharge bio-plasma (DBD), and assessed the characteristic change at the molecular level, one of the typical cellular responses. Heat shock protein 70 (HSP70) regulates its own protein level in response to stimuli. HSP70 responds to heat shock by increasing its own expression at the molecular level in cells. Hence, we confirmed the level of HSP70 after treatment of mouse embryonic fibroblasts (MEFs) with DBD. Interestingly, DBD-plasma induced cell death, but there was no difference in the level of HSP70, which is induced by heat shock stimuli, in DBD-treated MEFs. Our data provide the basic information on the interaction between MEFs and DBD, and can help to design a molecular approach in this field.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.6
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• pp.617-624
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• 2019

Dielectric barrier discharge (DBD) plasma is one of the promising next generation non-thermal technologies for food sterilization. The present study investigated the effects of DBD plasma on the reduction of most common food-borne pathogenic bacteria (Staphylococcus aureus, Bacillus cereus, Vibrio parahaemolyticus, Salmonella enterica) and sanitary indicative bacteria (Escherichia coli) in the suspension (initial inoculum of approx. 9 log CFU/mL). The bacterial counts were significantly (P<0.05) reduced with the increase in the treatment time (1-30 min) of DBD plasma in the suspension. The D-values (time for 90% reduction) of DBD plasma by first-order kinetics for S. aureus, B. cereus, V. parahaemolyticus, S. enterica, and E. coli were 17.76, 19.96, 32.89, 21.55, and 15.24 min, respectively (R²>0.90). These results specifically showed that 30 min of DBD plasma treatment in > 90% reduction of seafood-borne pathogenic and sanitary indicative bacteria. This suspension study may provide the basic data for use in seafood processing and distribution.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.172-172
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• 2012

Non-thermal plasma has attracted medical researchers, since they showed higher apoptosis rate in cancer cells than normal cells. However, it is hard to conclude general cancer cell specific effect because comparison between normal and cancer cell activities after plasma treatment have not been reported yet. This research proposes a comparison of Dielectric Barrier Discharge (DBD) plasma effect on three normal cells lines and three cancer cells lines. We measured cell number, mitochondria activity (MTS assay) and amount of hydrogen peroxide (H2O2) for three days. The results show that the number of cancer cells decreased more than normal cells following of exposure time. On the other hand, mitochondria activities and amounts of H2O2 increased following of exposure time. In addition, we found that DBD plasma exposure on cell suspension in media and media only illustrated no difference in mitochondria activity, H2O2 quantity, and cell number. Thus, we can confirm higher apoptosis rate in cancer cells which is related to the reactive oxygen species (ROS) generated by DBD plasma. The related molecular mechanisms were investigated further.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.195-198
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• 2014

$Fuel/N_2$ and fuel/air mixtures were treated with non-thermal DBD plasma and the changes in characteristics of laminar diffusion flame have been observed. Flame of $Fuel/N_2$ mixture generated more soot under plasma condition while less amount of soot was formed from fuel/air mixture flame. Luminescence spectrum and gas chromatography results confirmed that plasma energy converts a fraction of fuel molecules into radicals, which then form $C_2$, $C_3$, $C_4$ and higher hydrocarbon under no oxygen condition or turn into CO, $CO_2$ and $H_2O$ when oxygen is present.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.189-192
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• 2015

An experimental study was conducted to find the effect of DBD plasma on the flammability limits of inert-gas-diluted fuel. The results showed that the concentration of diluting nitrogen at flammability limit increased when nitrogen-diluted methane and propane were reformed by plasma, while it decreased when nitrogen-diluted ethylene was reformed by plasma. Gas chromatography results suggested that the fuel type dependence of flammability limits is due to the difference in the concentrations of hydrogen and hydrocarbon species in reformed fuel.