• Journal of Life Science
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• v.30 no.2
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• pp.178-185
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• 2020

Rice bakanae is a typical seed-borne and seed-transmitted disease caused by infection by Fusarium fujikuroi. Seed disinfection using chemical fungicides (such as benomyl and prochloraz) is most effective in controlling the disease, but the emergence of fungicide-resistant strains has recently been increasing. Slightly acidic hypochlorous acid water (SAHW) is a safe and environmentally friendly disinfectant that has a potent and broad spectrum of antimicrobial activity against viruses, bacteria, and fungi. In this study, we aimed to investigate the effectiveness of SAHW against F. fujikuroi strains, including chemical fungicide-resistant strains, as an alternative to conventional chemical fungicides in the management of bakanae disease. SAHW showed strong but similar levels of antifungal activity among the F. fujikuroi strains with a minimum inhibitory concentration (MIC₉₀) of 5±2.5 ppm of free available chlorine (FAC). In addition, F. fujikuroi cells lost viability completely within 5 min of SAHW treatment due to the lethal damage to cell integrity. When the rice seeds infected by F. fujikuroi were treated with SAHW containing 20±10 ppm of FAC for 12 hr, the efficiencies of seed disinfection and disease control were 95-98% and 90.1-92.6%, respectively. Altogether, our data suggest that SAHW is an effective compound for controlling rice bakanae disease.

• Journal of Animal Environmental Science
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• v.18 no.sup
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• pp.1-6
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• 2012

This study was conducted to verify the effect of chlorine dioxide ($ClO_2$) on odor reduction at a commercial swine facility consisting of a compost ficility. Compost facility in $NH_3$ concentration was around 550 ppm and less than 78 ppm before and after the $ClO_2$ spraying, respectively, which was over 86% reduction. There was no H2S detection. $NH_3$ concentration was around 420 ppm and less than 35 ppm before and after the $ClO_2$ spraying, respectively, which was over 83% reduction. $H_2S$ concentration was around 210 ppb and less than 32 ppb before and after the $ClO_2$ spraying, respectively, which was over 85% reduction. Hence, $ClO_2$ spraying at windowless barns was compost facility decreased malodor such as $NH_3$.

• Journal of the Mineralogical Society of Korea
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• v.26 no.1
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• pp.9-18
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• 2013

In order to optimize the gold leaching process from refractory sulfide concentrate, a chlorine-hypochlorite solution with varying concentrations and temperatures were applied to salt-roasted concentrate. The concentrate consisted of pyrite, chalcopyrite, and galena, which were turned into hematite through air-roasting at $750^{\circ}C$. Also these concentrates were changed into hematite and nantokite (CuCl)) through salt (NaCl)-roasting at $750^{\circ}C$. The results of the gold leaching experiments showed that the best gold leaching parameters were obtained when the hydrochloric acid-sodium hypochlorite mix was at a ratio of 1 : 2, the added concentration was 1.0 M concentration, the pulp density was 1.0%, and the leaching was done at a $60^{\circ}C$ leaching temperature. The leaching rate for gold was much greater in the roasted concentrate than in the raw concentrate. The leaching rate was greater in the salt-roasted concentrate than in the plain roasted concentrate too. From XRD analysis, quartz was found in the salt-roasted concentrate and in the solid residue from the chlorine-hypochlorite leaching solution at $60^{\circ}C$.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.4
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• pp.412-418
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• 2007

The purpose of this study was to determine the several factors for affecting chlorine disinfection by-products(DBPs) characteristics by reacting chlorine and organic matters in the aquatic phase. The results of this research yield the following specific conclusions: The concentration of trihalomethanes(THMs) was increased with increasing dissolved organic carbon(DOC), and a trend of THMs formation was parabolic with increasing organic matters. Formations of THMs increased straightly for the first 4 hours and the amounts of producted THMs for the 30 minutes were up to $25\sim43%$ in the entire experiment periods(168 hours). When keeping up the concentration of organic matters at constant and changing that of bromide, the quantity of formed THMs did not show distinguished difference with the reaction times. THMs were gradually increased at $4^{\circ}C$ even though a reaction phase was parabolic formation(PF) phase. However, THMs were increased rapidly in the instantaneous formation(IF) phase and then became slowdown in the PF phase between $20\sim35^{\circ}C$. THMs were gradually increased although entering in the PF phase at pH 5. However, THMswere increased rapidly in the IF phase and then became slowdown in the PF phase at pH 7 and pH 9, and these treads were much more clear at pH 9 than at pH 7.

• Journal of Chest Surgery
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• v.40 no.1 s.270
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• pp.1-7
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• 2007

Backgound: It has been shown that the endothelium of cardiac valves and adjacent great vessels have a reduced immune reaction compared to other vessels. We investigated the clinical feasibility of using immunologically untreated xenogenic valves, in a pig-to-goat pulmonary valve conduit implantation model. Material and Method: Porcine pulmonary valve conduits were prepared without specific immunologic treatment and implanted into the right ventricular outflow tract of goats while undergoing cardiopulmonary bypass. Two goats each were assigned to the following observation time intervals: one day, one week, three months, six months and twelve months. Echo-cardiographic examinations were performed prior to sacrifice of the goat to evaluate pulmonary valve function. After the xenograft specimens were retrieved, histological changes were evaluated microscopically. Result: Ten of the twelve animals survived the predetermined observation time intervals. Aneurysmal dilatations, of the anterior wall of the implanted pulmonary artery, were observed at each of three and twelve month-survival animals. A variable degree of pulmonary valve regurgitation was observed on echocardiography. However, valve stenosis, thrombotic occlusion and vegetation were not seen. Microscopically, the nuclei of the donor tissue disappeared as a result of pyknosis and karyolysis; however the three components of the implanted xenografts (the pulmonary artery, the valve and the infundibulum) were gradually replaced by host cells over time, while maintaining their structural integrity. Conclusion: Immunologically untreated xenogenic pulmonary valve conduits were replaced by host cells with few observed clinical problems in a pig to goat pulmonary valve implantation model. Therefore, they might be an alternative bioprosthesis option.

• Journal of Environmental Science International
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• v.21 no.8
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• pp.1015-1021
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• 2012

Formation of disinfection by-products (DBPs) including trihalomethans (THMs), haloacetic acid (HAAs), haloacetonitriles (HANs) and others from chlorination of algogenic organic matter (AOM) of Microcystis sp., a blue-green algae. AOM of Microcystis sp. exhibited a high potential for DBPs formation. HAAs formation potential was higher than THMs and HANs formation potential. The percentages of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) formation potential were 43.4% and 51.4% in the total HAAs formation potential. In the case of HANs formation potential, percentage of dichloroacetonitrile (DCAN) formation potential was 97.7%. Other DBPs were aldehydes and nitriles such as acetaldehyde, methylene chloride, isobutyronitrile, cyclobutanecarbonitrile, pentanenitrile, benzaldehyde, propanal, 2-methyl, benzyl chloride, (2-chloroethyl)-benzene, benzyl nitrile, 2-probenenitrile and hexanal.

• Food Science and Preservation
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• v.24 no.6
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• pp.827-833
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• 2017

This study was investigated the effects of various commercial sanitizers on microbial characteristics in fresh-cut iceberg lettuce during storage. For screening sanitizer, lettuce was cut and dipped in chlorine water ($0.2ml{\cdot}L^{-1}$), solution of organic acids such as ascorbic acid, citric acid, acetic acid, mixture of ascorbic acid and acetic acid (1-6%), and solutions of commercial sanitizers such as Formula 4$^{TM}$ (1,3,4%), Fresh produce wash$^{TM}$ (1,3,4%), Cleancol$^{TM}$ (1%), Chitochol$^{TM}$ (1%) and Natural Ca$^{TM}$ (0.1%) for 3 min, respectively. Washing lettuce with selected sanitizers resulted in reduction of aerobic bacteria of more than 2 log CFU/g. Initial pH of lettuce was related with the pH of sanitizers. pH ranged from 4.7 to 6.1 in Formula 4 (4%, pH 1.7) and Natural Ca (0.1%, pH 12.0), respectively. Chlorine water showed consistent and significant inhibition effect in all of microorganisms except total coliform. Over 3% of Formula 4 and Fresh produce wash were found to have high bactericidal activity among sanitizers. The sanitizers of chlorine water, Fresh produce wash, Chitochol and Natural Ca were effective in reducing yeast and mould populations. As coliform and E. coli, Formula 4 (4%) showed the highest bactericidal activity. The bactericidal effect of commercial sanitizers during storage varied with the kinds and concentrations of tested sanitizers. Although inhibition effect was not showed during storage, these results suggest that commercial sanitizers could be an alternative to chlorine for washing fresh-cut produce.

• Analytical Science and Technology
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• v.19 no.4
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• pp.290-300
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• 2006

Disinfection by-products(DBPs), such as volatile trihalomethanes and the nonvolatile organochlorine acids, created by chlorination have been extensively studied. However MX which contributes 20-50% of the mutagenic activity in drinking water began to people's attention since 1990. Its chemical name is 3-chloro-4-dichloromethyl-5-hydroxy-2(5H)-furanone. According to WHO guidelines its concentration should be controlled, but its value has not been set up. Due to analytical difficulties in measuring this compound at such a low concentrations and lack of information on toxicity to human. Because concentration (ng/L) of MX in drinking water is low traditional testing methods are ineffective. Therefore this study compared LLE and SPE and have chosen SPE to improve preconcentration. MX has been identified in chlorinated drinking water samples in several countries but not in korea Therefore this study analyzed concentration of MX in different water sources and in spring water. This study examined the causes of changing MX content. Chlorine dosage, seasons, water temperature and distance from the source was all discoverd to be relavant. MX was analyzed in various treatment to find optimum disinfection methods. The outcome was that the concentration of MX was minimized when using biological activated carbon-O3 and granular activated carbon.

• Journal of Environmental Science International
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• v.4 no.3
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• pp.277-284
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• 1995

There has been an increased awareness of the need to confirm the chloroform exposure associated with using chlorinated household water. Ten of a 30-minute tub bath were normally taken by two volunteers in a bathroom of an apartment. Chloroform concentrations were measured in bathing water and bathroom air, and exhaled breath of the subjects prior to and after bathing. Bathing using chlorinated tap water resulted in a chloroform exposure and caused a body burden. Based on the difference of chloroform concentrations between breath samples collected prior to and after bathing, the chloroform body burden from a 30-minute bath was estimated to be about 8 to 26 folds higher than that prior to the bath. The mean water and bathroom air chloroform concentrations measured to evaluate the body burden were $9.4\mu\textrm{g}/l$ and TEX>$14.9\mu\textrm{g}/m^3$, respectively. The chloroform level of the bathroom air was 각 to 130 times higher than that of the living-room air. The relationship between the bathroom air and the corresponding breath chloroform concentrations were significant with p=0.03 and $R^2=0.47$.

• Journal of Environmental Science International
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• v.4 no.3
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• pp.125-125
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• 1995

There has been an increased awareness of the need to confirm the chloroform exposure associated with using chlorinated household water. Ten of a 30-minute tub bath were normally taken by two volunteers in a bathroom of an apartment. Chloroform concentrations were measured in bathing water and bathroom air, and exhaled breath of the subjects prior to and after bathing. Bathing using chlorinated tap water resulted in a chloroform exposure and caused a body burden. Based on the difference of chloroform concentrations between breath samples collected prior to and after bathing, the chloroform body burden from a 30-minute bath was estimated to be about 8 to 26 folds higher than that prior to the bath. The mean water and bathroom air chloroform concentrations measured to evaluate the body burden were $9.4\mu\textrm{g}/l$ and TEX>$14.9\mu\textrm{g}/m^3$, respectively. The chloroform level of the bathroom air was 각 to 130 times higher than that of the living-room air. The relationship between the bathroom air and the corresponding breath chloroform concentrations were significant with p=0.03 and $R^2=0.47$.