• International Journal of Advanced Culture Technology
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• v.8 no.3
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• pp.211-215
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• 2020

Currently, most of the chlorine dioxide gas is processed at the beginning of storage or distribution. It has the disadvantage of not being able to continuously process gas since there is no system that can continuously process it during the distribution process. Therefore, in order to minimize changes in freshness and quality during the distribution process of agrifood, there is a need for a sustained-release chlorine dioxide gas treatment technology that can be continuously released. Therefore, in this study, the film to be used was examined so that the chlorine dioxide gas can be continuously released for a certain period of time, the concentration of the reactant and the viscosity at the time of the reaction were determined, and a chlorine dioxide gas gel pack was manufactured using this optimal condition. In addition, the gel pack was used to measure the amount of chlorine dioxide gas released and the sterilization effect of food poisoning bacteria.

• Journal of Sensor Science and Technology
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• v.29 no.3
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• pp.211-214
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• 2020

Chlorine dioxide is very effective gas for sterilization or disinfection (in manufacturing), and does not produce harmful by-products after use. However, if its concentration exceeds 10 %, it become explosive and cannot be compressed or stored. Therefore, it is necessary to measure its concentration. In this study, the concentration of chlorine dioxide with a high oxidizing strength was measured using a metal oxide sensor. The sensor was a commercially available TGS series from Figaro. The sensitivity of the sensor was inversely proportional to a low concentration of chlorine dioxide gas below 6 ppm and returned to the initial resistance at about 6 ppm. When the gas concentration reached multiples of 10 ppm, resistance of the sensor increased to several megaohms.

• Applied Chemistry for Engineering
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• v.25 no.4
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• pp.386-391
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• 2014

Atmospheric-pressure nonthermal corona discharge plasma was applied to the sterilization of biologically contaminated scoria powder. Escherichia coli (E. coli) culture solution was uniformly sprayed throughout the scoria powder for artificial inoculation, which was well mixed to ensure uniformity of the batch. The effect of the key parameters such as discharge power, treatment time, type of gas and electrode distance on the sterilization efficiency was examined and discussed. The experimental results revealed that the plasma treatment was very effective for the sterilization of scoria powder; 5-min treatment at 15 W could sterilize more than 99.9% of E. coli inoculated into the scoria powder. Increasing the discharge power, treatment time or applied voltage led to an improvement in the sterilization efficiency. The effect of type of gas on the sterilization efficiency was in order of oxygen, synthetic air (20% oxygen) and nitrogen from high to low. The inactivation of E. coli under the influence of corona discharge plasma can be explained by cell membrane erosion or etching resulting from UV and reactive oxidizing species (oxygen radical, OH radical, ozone, etc.), and the destruction of E. coli cell membrane by the physical action of numerous corona streamers.

• Restorative Dentistry and Endodontics
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• v.30 no.2
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• pp.121-127
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• 2005

A variety files made of stainless steel (S-S) or nickel-titanium (Ni-Ti) are used during endodontic treatment. The purpose of tt)is study was to evaluate the corrosion susceptibility of S-S and Ni-Ti endodontic files. Three brands of files were used for this study: $K-flex^{(R)}$ S-S files (Maillefer, USA), $Profile^{(R)}$ Ni-Ti files (Maillefer, USA), $K-3^{(R)}$ Ni-Ti files (SybronEndo. USA). 120 files of each brands (21mm, ISO size $\#20$) were divided into 12 groups according to 1) sterilization methods using Autoclave or Ethylene Oxide (E-O) gas, 2) Irrigation solutions using $5.25\%$ NaOCl or Saline, 3) the number of sterilization (1, 5, 10 times), After above procedures, each of the files was inspected by three examiners with a light microscope and camera at X25. Each file was judged and ranked according to the following criteria: 0;, no corrosion, 1; mild corrosion, 2; moderate corrosion, and 3; severe corrosion. The files of high score were examined under the Scanning Electron Microscope. Data were statistically analyzed with the Kruskal-Wallis test (p < 0.05). Most of the ten time-autoclaved files had showed mild to moderate corrosion. But, one or five time-autoclaved files did not show corrosive surface. NaOCl treatment and E-O gas sterilization did not influence on corrosion. There was a significant difference in corrosion susceptibility between sterilization methods and the number of autoclaving. However, there was no significant difference between brands and file materials.

• Korean Journal of Pharmacognosy
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• v.36 no.3 s.142
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• pp.220-223
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• 2005

The purposes of this study was to develop the best one among the methods using dry heat, gamma irradiation and alcohol gas, to sterilize Scutellariae Radix selected based on high frequency of circulation between merchants and high susceptibility to microbial contamination, through comparing these methods in terms of the followings; ⅰ) the efficacy of sterilization in comparison with cost, and ⅱ)the alteration of chemical components of these herbal medicines. The results of this study will be taken advantage of establishment of the maximum limit of microorganism contaminated in herbal medicines. From the results of this study we conclude the followings: ⅰ) The sterilizing method using dry heat may be inappropriate, because it seriously changed their color and morphology which is an essential criterion to estimate a measure of quality between merchants and consumers, although it effectively got rid of contaminated microorganism and did not alter major components, baicalin; ⅱ) The sterilizing method using gamma irradiation may be appropriate, because it showed a strong sterilizing effect, and no alteration of chemical components, color and morphology; ⅲ)The sterilizing method using alcohol gas may also be appropriate, because it had a similar effects as in the case of gamma irradiation. Collectively, we suggest that appropriate sterilizing methods to guarantee the microbial quality of this herbal medicine may be those using gamma irradiation and alcohol gas.

• Advances in environmental research
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• v.2 no.1
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• pp.1-8
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• 2013

There is a significant demand to make various dissolved gases in water. However, the conventional aeration method shows low gas mass transfer rate and gas utilization efficiency. In this study, a novel rotating wheel entraining gas method was developed for making high dissolved $O_2$ and $O_3$ in water. It produced higher concentration and higher transfer rate of dissolved $O_2$ and $O_3$ than conventional bubble aeration method, especially almost 100% of gas transfer efficiency was achieved for $O_3$ in enclosed reactor. For application of rotating wheel entraining gas method, aerobic bio-reactor and membrane bio-reactor (MBR) were successfully used for treatment of domestic and pharmaceutical wastewater, respectively; and vacuum ultraviolet $(VUV)/UV+O_3/O_2$ reactors were well used for sterilization in air/water, removal of dust particles and toxic gases in air, and degradation of pesticide residue and sterilization on fruits and vegetables.

• Journal of Korean Society of Archives and Records Management
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• v.1 no.1
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• pp.231-243
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• 2001

The sterilization method of records by fumigation using mixed gas of methyl bromide(MB) and ethylene oxide(ETO) has been generally used as a way to protect biological deterioration by microorganisms and insects. In this study, we confirmed sterilization effect of MB and ETO [86 : 14(Vol.%)] on and analyzed toxicity on microorganisms isolated from records. To analyze sterilization effect of fumigation on microorganisms and insect, we have fumigated microorganisms and insect with a various amounts mixed gas of MB and ETO, and various exposure time. Insect was sterilized at all experimental conditions. In microorganisms, sterilization effect was detected only when the mixed gas was treated at $120g/m^3$ concentration for at least 24 hrs. To test the possibility of isolated microorganisms as a threat to human health, it was investigated that toxicity test using yeast, radish and cancer cells on microorganisms. Only Aspergillus oryzae had an inhibition effect on growth of yeast. radish and cancer cells, respectively. These results demonstrate that sterilization effect can occur at low concentrations of the mixed gas on insect but requires higher concentrations of the mixed gas on microorganisms. In addition to, it is suspected that the possibility of the microorganism as a threat to human health is little.

• Journal of Microbiology
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• v.44 no.3
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• pp.269-275
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• 2006

Atmospheric-pressure cold plasma (APCP) using helium/oxygen was developed and tested as a suitable sterilization method in a clinical environment. The sterilizing effect of this method is not due to UV light, which is known to be the major sterilization factor of APCP, but instead results from the action of reactive oxygen radicals. Escherichia coli, Staphylococcus aureus, and Saccharomyces cerevisiae deposited on a nitrocellulose filter membrane or Bacillus subtilis spores deposited on polypropylene plates were exposed to helium/oxygen plasma generated with AC input power at 10 kHz, 6 kV. After Plasma treatment, nitrocellulose filter membranes were overlaid on fresh solid media and CFUs were counted after incubation overnight. D-values were 18 sec for E. coli, 19 sec for S. aureus, 1 min 55 sec for S. cerevisiae, and 14 min for B. subtilis spores. D-values of bacteria and yeast were dependent on the initial inoculation concentration, while the D-value of B. subtilis spores showed no correlation. When treated cells were observed with a scanning electron microscope, E. coli was more heavily damaged than S. aureus, S. cevevisiae exhibited peeling, and B. subtilis spores exhibited shrunken morphology. Results showed that APCP using helium/oxygen has many advantages as a sterilization method, especially in a clinical environment with conditions such as stable temperature, unlimited sample size, and no harmful gas production.

• YAKHAK HOEJI
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• v.49 no.2
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• pp.180-184
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• 2005

The purpose of this study was to develop the best methods to sterilize Moutan Root Bark which is frequently used as a herbal medicine, and known to have high susceptibility to m icrobial contamination. We used dry heat, gamma irradiation and alcohol gas treatment for sterilization, and evaluated these methods in terms of the followings; I) the efficacy of sterilization, and ii) the chemical alteration of a major component of the harbal medicines. Treatment with dry heat effectively got rid of contaminated microorganisms, and did not significantly alter the content of paeonol. However it seriously changed the color and morphology which are an essential criterion to estimate a measure of quality of medicinal herbs. Treatment with gamma irradiation showed a strong sterilizing effect, and no alteration of the content of paeonol, color and morphology. Alcohol gas treatment resulted in similar effects as those in gamma irradiation. Collectively, these results suggest that appropriate sterilizing methods to guarantee the microbial quality of this herbal medicine may be those using gamma irradiation or alcohol gas.

• YAKHAK HOEJI
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• v.50 no.6
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• pp.415-420
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• 2006

The purpose of this study was to develop the best methods to sterilize herbal medicines which is frequently used and known to have high susceptibility to microbial contamination. We used dry heat, gamma irradiation and alcohol gas treatment for sterilization, and evaluated these methods in terms of the followings; i) the efficacy of sterilization, and ii) the chemical alteration of index constituents of herbal medicines. Treatment with dry heat effectively eliminated the contaminated microorganisms, and did not significantly alter the content of berberine chloride, paeoniflorin and amygdalin in Phellodendron Bark, Peony Root and Apricot Kernel, respectively: However it seriously changed the color and morphology which are essential criteria to estimate a measure of quality of herbal medicines. Treatment with gamma irradiation showed a strong sterilizing effect, and no alteration of the content of index constituents, color and morphology: Alcohol gas treatment resulted in similar effects as those in gamma irradiation. Collectively; these results suggest that treatment with gamma irradiation or alcohol gas may be useful methods for sterilizing herbal medicines without a decrease in their microbial quality.