• Korean journal of applied entomology
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• v.39 no.2
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• pp.117-122
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• 2000

The chemosterilizing effects of 4 benzoylphenylureas (BPUs), were tested on the adult house fly at different developmental stages. The male and female flies before insemination (I-day-old) or with fully developed ovaries (5-day-old) were exposed to the flask surface coated with BPUs solution (300 ppm) for 24 hrs. None of the eggs layed by the 5-day-old flies on the next day of exposure to either flufenoxuron or teflubenzuron hatched to larvae. The eggs layed by the 5-day-old flies exposed to either triflumuron or diflubenzuron also showed a significantly reduced hatchability of 23%. The first egg batches layed by 1-day-old flies exposed to flufenoxuron showed hatchability of only 1%. These results indicate that the BPUs applied were effective in egg sterilization irrespective of developmental stage of house fly. The effect of flufenoxuron was the most pronounced and lasted for 5 days after exposure.

• Journal of Technologic Dentistry
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• v.31 no.3
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• pp.21-26
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• 2009

Purpose: Standards of alloy for porcelain fused to metal crown be classified by metallic factor and biological factor. Metallic factors consist of stability of alloy composition and mechanical strength and surface characteristics for chemical bond. Biological factors be considered properties of metallic elements and problems originated by toxicity and hypersensitive reaction. Alloys considered such controversial points are the most suitable alloy for dental instrument. Method: Alloys added Be and Nb using Ni-Cr alloy which has been widely used for dental instrument be selected and classified experimental group. Non-addition Be and Nb to Ni-Cr alloy classify control group and addition Be alloy is Be-experimental group, addition Nb alloy is Nb-experimental group. Specimens for cytotoxicity analysis gave effect to washing and sterilization. and then made an experiment on elution with cell medium after disinfection. It conducted specimens within cell medium with 24hours, 48hours, 72hours, respectively. It cultured human dermal fibroblast(HDF) using cell medium for cytotoxicity test and then investigated elution rate through spectroscopic analysis by MTT-assay. Result: As results of cytotoxicity test by MTT-assay, cultured cell rate of VII measured more low numerical value within elution medium for 24hours focused on control group. Also, cultured cell rate of K3 alloys observed low value for 48hours, 72hours than value of control group. Conclusion: According to final result that synthesize above results, Ni-Cr alloy added Be and Ni has little difference in Cytotoxicity by MTT-assay.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.39-39
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• 2017

In Asia, sweet potato (Ipomoea batatas) is a very important crop for starch production. Approximately 74.3% of the total sweet potato production quantity is produced in Asia (FAO, 2014) and China is the largest producer of sweet potato. Post-harvest management is particularly important because it is difficult to maintain the quality as well as quantity of sweet potatoes. Despite the importance of post-harvest management, researches on sweet potato have been focused on production-related study such as breeding of new variety, improved techniques of cultivation, so there is limited research on storage after harvest. Curing is a normal practice after sweet potato harvest to promote wound healing and extend postharvest storage life. In Korea, harvested sweet potatoes are usually cured for 4 to 7 days at $30-33^{\circ}C$ and 80-95% relative humidity within one week. Since the optimum storage temperature of sweet potato is regarded as $15-20^{\circ}C$, additional facilities and costs are required to raise the temperature for curing. However, the majority of small farmers do not have the capacity to provide additional facilities and costs. This study was initiated to suggest a new curing method to accelerate the wound healing by applying chemical oxidation to the wound surface of sweet potato. Oxidative stress is known to play an important role in the synthesis of secondary metabolites including lignin. In addition, chemical oxidation can be applied to prevent spoilage caused by microorganisms. Powerful gaseous oxidant with excellent penetration ability and superior sterilization effect was selected for this study. Lignification, weight loss, and spoilage rate of artificially wounded sweet potatoes were investigated after oxidant fumigation. There were clear differences in morphological analysis such as lignification pattern, lignin deposition color, and continuity of lignified cell layers between oxidant-fumigated sweet potatoes and control. These results show that gaseous oxidant can be used to supplement or replace the curing practice, to improve shelf-life as well as curing cost reduction.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.2
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• pp.111-119
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• 1976

Discoloration of canned boiled oyster namely greening, yellowing and browning often occur separately or associatively in the storage of the product. Greening is mainly caused by the appearance of chlorophyll and its derivatives on the surface around the digestive diverticula of the oyster and yellowing by dispersion of carotenoid. Browning reactions by sugar amino condensation or enzymatic action, tyrosinase, also cause an undesirable color development. In this paper, the stability and the changes in distributional or partitional ratio of chlorophyll and carotenoid pigment of meat vs viscera in raw and canned oyster during six month storage in order to measure the dispersion rate of both pigments between meat and viscera, and to evaluate the feasibility of discoloration of oyster meat. The development of brownish pigment and the toss of free tyrosine in oyster were also determined to compare the readiness of color development. In addition the influence of processing and storage conditions to the dispersion rate and the tendency of discoloration, and finally the effect of inhibitor were discussed. The results showed that greening or yellowing was initiated by the dispersion of chlorophyll or carotenoids from viscera to the meat of oyster, and the dispersion rate of carotenoid was much higher than the chlorophyll's, so that, yellowing appeared a leading reaction of discoloration. The dispersion rate was obviously fastened by raising the temperature in the process of sterilization and storage. Consequently, the low temperature storage could largely retard the occurance of yellowing or greening of oyster meat. The pH control of canned oyster did not seem to affect the dispersion of pigment but significantly did on the stability of the piqments. Browning by the reaction of sugar-amino condensation and enzymatic oxidation of tyrosine was positively detected in canned oyster meat. The development of brownish color was influenced rather by the storage temperature than the heating process. Addition of sodium sulfite in can or treating the boiled oyster with sulfite solution prior to filling seemed possibly inhibit the color development particularly in cold-storaged oyster meat.

• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.116-122
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• 2000

On the instrumented root canal wall, amorphous, irregular smear layer can be observed with Scanning Electron Microscope(SEM). The purpose of this study was to evaluate the effect of the presence or absence of smear layer on the adhesion of Staphylococcus aureus to the dentin of the root canal. Human incisors, extracted within 7 days, with no caries, no fracture, no calcification of canal, were selected. After cutting crown portion at cemento-enamel junction, root canal preparation was done by modified crown-down technique using Profile and Gates - Glidden Drill. During canal preparation, 10ml physiologic saline solution(group1&3) or 10ml 3.5% NaOCl(group2&4) was used as irrigation solution. And 10ml physiologic saline solution(group1&3) or 10ml 0.5M EDTA(group2&4) was applicated for final flush. After vertical sectioning and ethylene oxide gas sterilization, samples(group1&2) were immersed into BHIYHM broth inoculated with Staphylococcus aureus (ATCC 31153) and incubated for 3hrs at $37^{\circ}C$. All samples were prepared for and observed with SEM(JEOL JSM840S). The data were analyzed by Mann-Whitney rank sum test. The conclusions are as follows ; 1. Smear layer covers entire root canal surface after root canal preparation. 2. Smear layer has been removed away and the entrances of dentinal tubules have opened widely, when applying 0.5M EDTA and 3.5% NaOCl. 3. A significantly higher number of bacteria were adhered to the root canal dentin without smear layer(p<0.0001). 4. Smear layer produced during root canal preparation impedes bacterial adhesion and colonization to dentin matrix, therefore inhibits canal reinfection.

• Korean Journal of Medicinal Crop Science
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• v.2 no.3
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• pp.211-218
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• 1994

This experiment was conducted to obtain basic information for the establishment of in vitro initial culture system in Fritillaria thuubergii Miq. Methods of surface sterilization of scale segments as explant and effect of antibiotics added into the culture medium on contamination of explant and chilling treatment of mother bulb on bulblet formation were investigated. Portent of contamination of cultured scale segments was significantly higher in the outer scale segments which were unsuitable as initial culture explant than inner scale segments. Contamination of explants taken from inner scale of bulb was reduced by surface sterilizing explants in the solution of $4{\sim}5%$ sodium hypoclorite for $10{\sim}15$ mimutes. Addition of antibiotics such as kanamycin, vancomycia cefotaxim, agrirnycin and agreptomycin and dithane as fungicide and$lncyte^{tm}$ into MS medium was effective to reduce bateriological contamination, but did not work to control fungi. It had effective to delay the degree of contamination caused by fungi and bacteria haboring in cultured explants. Bulblet formation from cultured scale segments was promoted by dry storage for $2{\sim}4$ weeks or moisture storage of mother bulbs for $4{\sim}6$ weeks at $10^{\circ}C$ before excision of explants. Addition of kinetin into medium could not exerted for the bulblet formation from the scale segment of dry storaged bulb compared to control. But explant taken from 6 week moisture storaged bulb formed more than 10 bulblets per explant on the medium containing $3{\sim}5mg/L$ kinetin.

• Journal of agriculture & life science
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• v.53 no.3
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• pp.27-39
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• 2019

The purpose of this study was to investigate the effect of hot water treatment and pH corrected lime sulfur combination treatment on the fungicidal and bacterial disinfection effects and germination rate of organic lettuce seeds. Among the followers, Alternaria sp. was infected 53.3% and Aspergillus sp. and Cladosporium sp. Infected 14.5% and 5.4%, respectively. Bacteria were isolated only Pseudomonas sp., and infected with 16.5%. In order to investigate the effect of disinfection on the temperature of hot water (45℃, 50℃, 55℃ and 60℃). The seed germination rate sharply decreased with increasing temperature and treatment time. The germination effect and germination rate of the follower were highest when hot water treatment was carried out for 20 minutes in hot water at 50℃. In the case of combined treatment of 50℃ hot water for 10 min and 0.4% pH adjusted lime sulfur mixture, showed the highest sterilization effect and germination rate with 100% and 97.6%, respectively. The results of this study can contribute to the development of technology to sterilize not only seed surface but also fungi and bacteria inside of seed.

• Research in Plant Disease
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• v.20 no.4
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• pp.283-288
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• 2014

Citrus canker caused by Xanthomonas citri subsp. citri (Xcc) has been quarantined by many countries in the world. Recently, the usage of methyl bromide should be limited, application by gamma irradiation on the agricultural production is raised as an alternative method. In this study, the level of gamma irradiation which could decrease of population of Xcc in the suspension or on the surface of citrus fruit was investigated. The $D_{10}$ value of Xcc, which is radiation dose required to reduce the number of the microorganism, was 55 and 28 Gy in the suspension and on the surface of citrus fruit, respectively. Furthermore, disease severity was suppressed on the citrus leaves inoculated with Xcc suspension pre-treated with gamma irradiation. Based on this study, it is suggested that Xcc on the citrus fruit could be eradicated by gamma irradiation and the results of this study may be valuable for application of gamma ray in quarantine activity.

• Journal of Food Hygiene and Safety
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• v.39 no.1
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• pp.54-60
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• 2024

This study investigated the effectiveness of using pathogens and aqueous acids to reduce the Aspergillus ochraceus and Rhodotorula mucilaginosa contamination in livestock production environments. For this study, 1 mL of each bacterial suspension (10⁷-10⁸ spores/mL) was inoculated on a knife surface, dried at 37℃, and used under each treatment condition. First, to investigate the effect of organic acids, acetic, lactic, and citric acids were used. Subsequently, to select the appropriate concentration, they were prepared at concentrations of 0.5, 1, 2, 3, 4, and 5%, respectively. Accordingly, to further maximize the effect of organic acid treatment, we combined the treatment with ultraviolet light. The two strains showed a significant difference (P<0.05) compared to the initial strain, with a greater than 90% decrease in the concentrations of all organic acids. Consequently, acetic and lactic acids decreased by approximately 5 and 2 log colony forming unit (CFU)/cm², respectively, when treated with ultraviolet light (360 mJ/cm²); however, citric acid decreased by less than 1 log CFU/cm². However, when manufactured with 4% acetic acid, a severe malodor was emitted, making it difficult for workers to use it in a production environment. Accordingly, the optimal treatment conditions for organic acid and ultraviolet light for application were selected as follows: immersion in a 4% lactic acid solution for 1 minute and then, sterilization with ultraviolet light at 360 mJ/cm². Finally, when a pork meat sample was cut with a knife that was finally washed with lactic acid and treated with ultraviolet light, the low level of inoculum transferred from the cleaned knife to the surface of the sample was not detected. In conclusion, using this established method can prevent cross-contamination of the surface of the meat during processing.

• Journal of Applied Biological Chemistry
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• v.60 no.2
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• pp.149-153
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• 2017

Contamination and growth of Trichoderma, a green mold, on the oak log and wooden chip or sawdust media can severely inhibit the growth of oak mushroom. Chemicals including pesticides and antibiotics are generally not allowed for the control of green mold disease during mushroom cultivation. In this study, bacterial pathogens causing blotch disease on the oyster mushrooms were isolated and their peptide toxins were purified for the control of green mold disease. Strains of Pseudomonas tolaasii secret various peptide toxins, tolaasin and its structural analogues, having antifungal activities. These peptides have shown no effects on the growth of oak mushrooms. When the peptide toxins were applied to the green mold, Trichoderma harzianum H1, they inhibited the growth of green molds. Among the 20 strains of peptide-forming P. tolaasii, strong, moderate, and weak antifungal activities were measured from 8, 5, and 7 strains, respectively. During oak mushroom cultivation, bacterial culture supernatants containing the peptide toxins were sprayed on the aerial mycelia of green molds grown on the surface of sawdust media. The culture supernatants were able to suppress the fungal growth of green molds while no effect was observed on the mushroom growth and production. They changed the color of molds from white aerial mycelium into yellowish dried scab, representing the powerful anti-fungal and sterilization activities of peptide toxins.