• Korean journal of applied entomology
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• 제18권2호
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• pp.63-71
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• 1979

Tests were made to find new non-mercurious seed disinfectants that were best for rice seeds. For these experiments four seed samples carr)?ing natural infection of Pyricularia oryzae, Helminthosporium oryzae, and Fusarium moniliforme were used and the following fungicides were used; Zinc Omadine, Sodium Omadine, Panoctine, Tecto-F, Benlate-T, Homai, Sisthane, $P_{242}$, Busan 30, Tecto-Wp and Terracoat Zn. Blotter method and water agar plate method used in the laboratory and growing-on test used in greenhouse. Results have shown that Sisthane, $P_{242}$ and Sodium Omadine have equal or superior effect to organic mercury compound against P. oryzae, H. oryzae, and F. moniliforme. Benlate T and Homai are effective against blast and Bakanae disease, but are inferior to organic mercury compound against brown spot disease. Busan 30 and Panoctine are effective against blast and brown spot disease, but have moderately inferior effects against F. monilifome. It is considered that the recommendable testing methods of seed treatment were blotter method for P. oryzae and water agar plate method for H, oryzae and F. moniliforme according to the experimental results obtained. No phytotoxicity against seed germination and seedling growth were observed when treated with disinfectants before germination of seeds.

• Journal of environmental and Sanitary engineering
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• 제20권3호
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• pp.36-43
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• 2005

Prior to the study of the sewage treatment methods, water quality for Gwangju sewage of fluent was investigated from January to December, 2004 for sewage water reuse. Monthly mean values of BOD, SS, turbidity, total phosphorus and color were 4.1 mg/L, 2.9 mg/L, 0.8 NTU, 1.3 mg/L, and 27 unit, respectively. Jar-test was performed to investigate the removal efficiency of pollutants under the coagulation conditions of fast mixing for 5 min, slow mixing for 15 min and precipitation for 1hr. Here, alum and polyaluminium chloride (PAC) were used as coagulants to reduce color, turbidity, total phosphorus (TP) and total organic carbon (TOC) in sewage effluents. The results showed that PAC gave better efficiency in removing turbidity and dissolved phosphorus than alum. It was also found from the relative molecular weight (RMW) distribution analysis that organic matter over 1,000 Dalton (Da) was easily removed by coagulation and subsequently MF treatment, while it was not effective for less than 500 Da. Based on tis result, Natural organic matter (NOM) with lower molecular weight (< 500 Da) may cause harmful disinfectant by-product (DBP) after chlorine treatment. Thus, activated carbon adsorption seems to be required for the complete removal of DBP in the hybrid system.

• Restorative Dentistry and Endodontics
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• 제40권1호
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• pp.50-57
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• 2015

Objectives: The usage of medicinal plants as natural antimicrobial agents has grown in many fields including dental medicine. The aim of this in vitro study was three-fold: (i) to determine the chemical compositions of the Ferula gummosa essential oil (FGEO), (ii) to compare the antimicrobial efficacy of the oil with sodium hypochlorite (NaOCl) and chlorhexidine (CHX), (iii) to assess the toxic behavior of FGEO in different concentrations compared to 5% NaOCl and 0.2% CHX. Materials and Methods: Gas chromatography/mass spectrometry (GC/MS) was used to determine the chemical compositions of the oil. The disk diffusion method and a broth micro-dilution susceptibility assay were exploited to assess the antimicrobial efficacy against Enterococcus faecalis, Staphylococcus aureus, Streptococcus mitis, and Candida albicans. The cytocompatibility of the FGEO was assessed on L929 fibroblasts, and compared to that of NaOCl and CHX. Results: Twenty-seven constituents were recognized in FGEO. The major component of the oil was ${\beta}$-pinene (51.83%). All three irrigants significantly inhibited the growth of all examined microorganisms compared to the negative control group. FGEO at $50{\mu}g/mL$ was effective in lower concentration against Enterococcus faecalis than 5% NaOCl and 0.2% CHX, and was also more potent than 0.2% CHX against Candida albicans and Staphylococcus aureus. FGEO was a cytocompatible solution, and had significantly lower toxicity compared to 5% NaOCl and 0.2% CHX. Conclusions: FGEO showed a promising biological potency as a root canal disinfectant. More investigations are required on the effectiveness of this oil on intracanal bacterial biofilms.

• Journal of Korean Society of Water and Wastewater
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• 제32권6호
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• pp.527-533
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• 2018

Microorganisms detected in the biofilm not only cause secondary pollution of drinking water such as taste, odor and pathogenic disease but also increase the amount of disinfectant due to microbial regrowth during the transportation of tap water. In this work, the influence of C/N ratio in tap water on the characteristics of biofilm growth was examined. The C/N ratio of the tap water sample was controlled at 100:5, 100:10, 100:20, 100:30, and 100:40 by adding appropriate amounts of dextrose and $(NH_4)_2SO_4$. Of the five C/N ratios, heterotrophic plate counts (HPC) was highest at the ratio of 100:10. Following the initial formation in all the five experimental conditions, natural detachment of the biofilm was observed. Extracellular enzyme activity (EEA) analyses showed that the change of the EEA during the experimental period was similar to that of the HPC, demonstrating a positive correlation between HPC and EEA. For TOC concentration in the tap water sample, approximately 75% of the TOC was consumed in 7 days of the experiment and 96% in 28 days. The TOC appeared to be relatively rapidly consumed at the initial phase of the biofilm growth. Consumption pattern of the ammonia nitrogen was different from the TOC consumption pattern showing the different role of ammonia nitrogen on the growth of biofilm.

• Journal of Food Hygiene and Safety
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• 제29권2호
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• pp.117-122
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• 2014

Rice can be the contaminating with soil-borne bacteria. Furthermore, the contaminated bacteria can be grown during immersion process for produce wet-milled rice flour. Therefore, disinfectants can be added during the immersion process. Antibacterial activities of the natural disinfectant, fermented rice spent water (FRSW), and the chemical disinfectants, chlorine dioxide (CD) and sodium benzoate (SB), were respectively determined when added in pure cultures of target bacteria such as Salmonella typhimurium, Escherichia coli, and Bacillus cereus or when added to immersion water in the immersion process. In addition, rinsing effects for removing bacteria were determined when rice was rinsed with water before and after the immersion process. Antibacterial activities were rapidly increased as increasing amounts of the disinfectants are added to the pure cultures of the target bacteria. Antibacterial activity of CD was the most effective among the three tested disinfectants when added to the pure cultures of the target bacteria, respectively. Those of the same disinfectants were increased when they were increasingly added to the immersion water. However those of the disinfectants were less effective when added to the immersion water. On the other hand, rinsing effects for removing bacteria were the most effective when rice was rinsed only with water without the immersion process. Collectively, rinsing rice with water only was more effective than using disinfectants in the immersion water during rice flour production.

• Korean Journal of Environmental Biology
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• 제35권2호
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• pp.116-122
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• 2017

Basic dyes such as malachite green and methylene blue have been used as disinfectants to control water fungal infections since the 1930s. However, after succeeding reports of carcinogenicity and bioaccumulation of the dye, their use was forbidden in lieu of public health. This study undertook to evaluate the therapeutic effect of sulfur solution processed by effective microorganisms (EM-PSS) against Saprolegnia parasitica infection, and its safety in fish. In vitro antifungal evaluation of EM-PSS inhibited the growth of S. parasitica mycelia at concentrations of 50 ppm or higher. The acute toxicity test of EM-PSS to the mud fish (Misgurnus mizolepis) measured a no effect concentration (NOEC) at 100 ppm, the lowest effect concentration (LOEC) at 125 ppm, and the half-lethal concentration ($LC_{50}$) at 125 ppm in juvenile and 250 ppm in the immature stage. In addition, the ecotoxicity test of EM-PSS using Daphnia magna inhibited swimming of D. magna at concentrations of 100 ppm or less. Lastly, the EM-PSS prevented infection of S. parasitica to mud fish, at concentrations of 50 ppm. Furthermore, at 100 ppm concentration, the EM-PSS showed no acute toxicity on mud fish, nor any eco-toxic effects on D. magnano. Therefore, we conclude that carcinogenic disinfectants such as malachite green and methylene blue could be replaced by EM-PSS to remove S. parasitica in mud fish farming, and might be a potential eco-friendly disinfectant in aquaculture.