• Journal of Life Science
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• v.31 no.7
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• pp.609-616
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• 2021

Bacterial soft rot, caused by Pectobacterium carotovorum subsp. carotovorum (Pcc), is one of the destructive diseases of radish (Raphanus sativus) in Asian countries. The objective of this study was to establish an efficient bioassay method for the evaluation of bacterial soft rot resistance in commercial radish cultivars. First, an efficient bioassay method for examining resistance to bacterial soft rot in commercial radish cultivars was investigated. Six commercial radish cultivars were tested under various conditions: two temperatures (25℃ and 30℃), three inoculations methods (drenching, spraying, and root dipping), and two growth stages (two- and four-leaf stages). The results suggested that spraying with 1×10⁶ cfu/ml of bacterial inoculums during the four-leaf stage and incubating at 30℃ could be the most efficient screening method for bacterial soft rot resistance in commercial radish cultivars. Second, we investigated the degree of resistance of 41 commercial radish cultivars to five Pcc isolates, namely KACC 10225, KACC 10343, KACC 10421, KACC 10458, and KACC 13953. KACC 10421 had the strongest susceptibility in terms of moderately resistant disease response to bacterial soft rot. Out of the 41 radish cultivars, 13 were moderately resistant to this pathogen, whereas 28 were susceptible. The moderately resistant radish cultivars in this investigation could serve as resistance donors in the breeding of soft rot resistance or could be used to determine varietal improvement for direct use by breeders, scientists, farmers, researchers, and end customers.

• Journal of the Korea Institute of Building Construction
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• v.22 no.6
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• pp.651-662
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• 2022

The electrochemical impedance spectroscopy(EIS) method was used to evaluate the concrete deterioration process related to chloride-induced steel corrosion with various corrosion levels(initiation, rust propagation and acceleration periods). The impressed current technique, with four total current levels of 0C, 13C, 65C and 130C, was used to accelerate steel corrosion in concrete cylinder samples with w/c ratio of 0.4, 0.5, and 0.6, immersed in a 0.5M NaCl solution. A series of EIS measurements was performed to monitor concrete deterioration during the accelerated corrosion test in this study. Some critical parameters of the equivalent circuit were obtained through the EIS analysis. It was observed that the charge transfer resistance(R_c) dropped sharply as the impressed current increased from 0C to 13C, indicating a value of approximately 10kΩcm². However, the sensitivity of R_c significantly decreased when the impressed current was further increased from 13C to 130C after corrosion of steel had been initiated. Meanwhile, the double-layer capacitance value(C_dl) linearly increased from 50×10^-6μF/cm² to 250×10^-6μF/cm² as the impressed current in creased from 0C to 130C. The results in this study showed that monitoring C_dl is an effective measurement parameter for evaluating the progress of internal concrete damages(de-bonding between steel and concrete, micro-cracks, and surface-breaking cracks) induced by steel corrosion. The findings of this study provide a fundamental basis for developing an embedded sensor and signal interpretation method for monitoring concrete deterioration due to steel corrosion at various corrosion levels.

• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.839-852
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• 1997

It has been submitted that different ion solutions containing sulfate induce crystal growth and might substitute conventional acid etching for pretreatment of enamel in orthodontic bonding(${\AA}rtun$ et al., Am. J. Orthod. 85, 333, 1984). This investigation was designed to evaluate the relevance of crystal growth on the enamel surface as an alternative to conventional acid etching in direct bonding of orthodontic brackets. Annexing Li2SO4, MgSO4, K2SO4 respectively in the solution with $25\%$ polyacrylic md 0.3M sulfuric acids were employed to enhance the crystal growth. Human bicuspids were treated with various parameters as combinations of crystal growth and glass ionomer cement, crystal growth and orthodontic resin, acid etching and orthodontic resin for an investigative purpose. Crystal growth solution containing MgSO4 showed the highest shear bond strength(15.6MPa) within the groups of bonding brackets with glass ionomer cement(p<0.01). Bonding with glass ionomer cement on the surface of crystal growth demonstrated higher shear bond strength than with orthodontic resin(p<0.001). Bonding with glass ionomer cement on the surface treated with crystal growth solution containing MgSO4 or K2SO4 was not different shear bond strength statistically from bonding with orthodontic resin on the acid-etched surface. It suggests that bonding brackets with glass ionomer cement on the surface treated with crystal growth solution containing MgSO4 or K2SO4 is a potential alternative to bonding with resin on the acid etched sufrace.

• Korean journal of applied entomology
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• v.40 no.1
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• pp.69-76
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• 2001

The entomopathogenic nematodes, Steinernema carpocapsae Pocheon strain (ScP) and Heterorhabditis bacteriophora Hamyang strain (HbH) were evaluated against chestnut insect pests, The farmers＇handling methods of chestnuts were taken into consideration to develop practical biological control with entomopathogenic nematodes . The major insect pests found with chestnuts were Curculio sikkimensis, Seichocrocis punctiferalis, and Cydia kurokoi. Although individual chestnut contained one species of insect was 58% representing 18% by C. sikkimensis, 27.7% by D. punctiferalis and 12.3% by C. kurokoi. The percentage of co-infection of C. sikkimensis with D. punctiferalis was 3.3%, C. sikkimensis with C. kurokoi 5.0%, D. punctiferalis with C. kurokoi 7.7%, and C. sikkimensis with D. punctiferalis and C. kurokoi 5.0%. The entomopathogenic nematodes, ScP and HbH were effective against all the species of chestnut insect pests. The $LC_{50}$ of ScP was 14.6 for C. sikkimensis, 4.6 for D. punctiferalis, and 5.6 for C. kurokoi and that of HbH was 49.2 for C. sikkimensis, 5.8 for D. punctiferalis, and 13.9 for C. kurokoi, respectively. When ScP was applied into pot including harvested chestnuts at the rate of 4,813 infective juveniles (Ijs)/pot $(=1\times10^9/ha)$, mortality of C. sikkimensis, D. punctiferalis, and C. kurokoi was 85.3%, 96.9%, and 68.1%, respectively. The mortality of C. sikkimensis, D. punctiferalis, and C. kurokoi was 60.73%, 96.5%, and 66.8%, respectively when HbH was applied at the same rate. Combination of two nematode species produced similar effects and insects were more infected by ScP than HbH. When chestnuts were soaked in the suspension of ScP at the rate of 300, 3,000, and 30,000 Ijs for 10 minutes or 30 minutes, mortalities of all chestnut insects were high irrespective of soaking time, concentration , and nematode species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.1
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• pp.25-37
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• 1978

Since 1976 the catches of sardine increased rapidly in Korea. However due to the poor facilities of preservation, most sardine landed was used only for fish meal as feeds. The aims of this study are to investigate the processing of sardine as a protein. concentrate and to solve related problems under our particular circumstances. Using the ethyl alcohol and isopropyl alcohol, the storage effect for further processing, the optimum processing conditions of sardine protein concentrate and amino acid composition of the product were determined. The utilization of sardine protein ,concentrate as a supplement of bread and noodles was also studied. Chopped sardine meat could be stored in isopropyl and ethyl alcohol without significant deterioration as a raw material for tile further processing. High qualify sardine Protein concentrate could be produced by the method, that is five times five minutes extraction with isopropyl or ethyl alcohol at $80^{\circ}C$ under adequate mixing. In the first step of the extraction, the solvent was added as much as 10 times tile sample amount and the equal volume of additional solvent was also used for the second to fifth step extraction. In the products extracted using isopropyl alcohol and ethyl alcohol, the yields of sardine protein concentrate were $21.2\%$ and $20.3\%$ respectively, and the dry basis contents of protein in the two products were $80.5\%$ and $75.8\%$, the lipid being $0.22\%$ and $0.27\%$ respectively. Isoproyl alcohol was superior to superior alcohol for the extraction of fresh sardine. In amino acid composition of sardine protein concentrate, no difference was found between the products of isopropyl and ethyl alcohol extraction except a little difference in the amount of amino acid between them. In the supplementation of bread and noodles, taste panel showed that supplemented bread and noodles were well accepted when $3\%$ of wheat flour was replaced by sardine protein concentrate.

• Food Science and Preservation
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• v.17 no.1
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• pp.50-57
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• 2010

To develop a new functional kimchi with antioxidative properties, salted baechu was soaked in black rice water extract for 6 h at room temperature. The antioxidative property of the water extract was $78.75{\pm}1.18%$ that of the control (0.1% [w/v] alpha-tocopherol). The black rice gel was added to the baechu kimchi preparation. The color of baechu kimchi treated with black rice water extract changed to dark violet and/or black. Control kimchi and black rice water-treated kimchi were stored at $4^{\circ}C$ for 30 days. No significant differences were detected between the control and the black rice water-treated group in the early stages of fermentation. As fermentation time increased, pH decreased and titratable acidity increased rapidly in control kimchi. However, such marked changes were not evident in test kimchi. The hardness value of black rice water-treated kimchi was higher than that of control kimchi after the midpoint of the fermentation period. The storage life of baechu kimchi treated with black rice water extract was prolonged by up to 5 days compared with control samples, owing to a decline in lactic acid bacteria and yeast levels during the final fermentation period in black rice water-treated kimchi. The total phenolic levels and the antioxidative capacity of black rice water-treated kimchi (83%) were approximately 1.5-fold higher than in control kimchi (57%). In sensory evaluation, black rice water-treated kimchi scored higher than did control kimchi using a blind test protocol.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.6
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• pp.875-880
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• 2012

This study was conducted to investigate the level of contamination of pathogenic Escherichia (E.) coli in 50 types of red pepper powders collected domestically. Pathogenic E. coli was confirmed using real-time PCR to confirm the 4 types of EAEC, EPEC, EHEC and ETEC. One sample out of 50 was contaminated with pathogenic E. coli. The type of pathogenic E. coli detected in the sample was EAEC. This study was also conducted to determine the effect of alcohol treatment on the reduction of E. coli populations in red pepper powder. The amount of E. coli in the control was $1.2{\times}10^6$ cfu/mL. The amount of E. coli in 10 minutes immersion treatment with 10% alcohol was $1.1{\times}10^6$ cfu/mL. In samples treated with over 20% alcohol, E. coli was not detected. This showed that 10 minutes of immersion in over 20% alcohol might be effective to reduce E. coli. This study was also conducted to determine the effect of UV irradiation on E. coli reduction. The number of E. coli in the control group was $5.0{\times}10^5$ cfu/mL. However, the number of E. coli in 45 min of the UV irradiated sample decreased to $1.0{\times}10^3$ cfu/mL, by $10^2$ cfu/mL. In contrast, E. coli was not detected in an over 60 min UV irradiated sample in $10^{-2}dilution$. This study showed that over 20% alcohol treatment and UV irradiation for 60 min was effective to control E. coli in red pepper powder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.4
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• pp.316-324
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• 1985

Vacuum-packed and seasoned smoked-dried products of red squid, Ommastrephes bartrami, caught in the Northern Pacific Ocean, were prepared and stored at room temperature for 90 days to test their keeping quality. Defrosted squids were eviscerated, skinned, and cut. The mantle meats were flavored with seasoning powders prepared from sugar, sorbitol, salt, monosodium glutamate, or smoke flavor (Smoke-EZ, Alpha Foods Co., Ltd.). After seasoning, the mantle meats were dried at $45^{\circ}C$ for 7 hours, vacuum packed in plastic film bags, and pasteurized in water at $95^{\circ}C$ for 30 minutes. Three kinds of products were prepared : control products (seasoned-dried), solid smoked seasoned-dried and liquid smoked seasoned-dried. The moisture level, water activity, color value (L, a and b value), texture, and viable cell counts of bacteria in these products were determined during storage at room temperature, $5^{\circ}C\;and\;35^{\circ}C$, respectively. The results showed that the products could be preserved at good condition for 90 days though they developed pale brown color during storage. The contents of free amino acids, nucleotides and their related compounds, and the compositions of fatty acids of raw squid and smoked products were analysed. In the amino acids, arginine, taurine, glycine and proline were abundant in raw and smoked products. The contents of hypoxanthine of raw and smoked products were higher than the other nucleotides and their related compounds. In fatty acid compositions of raw and smoked products, the dominant fatty acids were docosahexaenoic acid (22:6), hexadecanoic acid(16:0) and eicosapentaenoic acid (22:5).

• Korean Journal of Food Science and Technology
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• v.26 no.3
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• pp.317-323
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• 1994

Nine plant foods (persimmon leaf, perilla seed, Chinese quince, ginger root, walnut, mugwort leaf, arrowroot, buckwheat and sorghum) rich in phenolic substances were examined for their effects on the digestive enzymes, food-poisoning bacteria and mutagenicity/antimutagenicity by Ames test. Among tested samples, Chinese quince significantly inhibited the $\alpha-amylase$ activity (97%), exhibiting an uncompetitive inhibition type. Protease activity was inhibited by Chinese quince (86%), persimmon leaf (51%) and mugwort leaf (20%), in which mugwort extract exhibited a noncompetitive type. Lipase was activated >50% by all samples. The inhibition of $\alpha-amylase$ was highly correlated with the content of condensed tannin (r=0.89) and the inhibition of protease, with total phenolic content (r=0.84). Total phenolies fraction of tested samples showed the growth inhibition toward E. coli. Streptococcus faecalis and Salmonella enteritidis, in which the effect of perilla, sorghum and arrowroot was the highest for E. coli. Standard phenolics and food samples did not show any mutagenicity toward Salmonella typhimurium TA98 and TA100. Tannic acid inhibited the mutation of the two strains by benzo[a]pyrene whereas total phenolics fractions of Chinese quince and walnut exhibited antimutagenicity to a lesser extent.

• Journal of Korean Society of Forest Science
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• v.78 no.2
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• pp.103-118
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• 1989

The occurrence of witches' broom in Ligustrum ovalifolium was first noticed in Korea by author in 1984. The present study was carried out with particular emphasis on the symptomatology, etiology, transmission of the disease and antibiotic treatments. The infected tissue was observed by the fluorescence and electron microscopy and its biochemical characteristics were compared with healthy one by electrophoresis. The results are summarized as follows : 1. symptoms of the infected trees were characterized by the dwarfing of the organs, yellowing and brooming of the foliage. 2. The observation by the trans electron microscopy on the witches' broom of L. ovalifolium revealed the occurrence of numerous mycoplasma-like organisms(MLOs) in the phloem tissue cells of the midribs of infected leaves. 3. The MLOs were surrounded by a single unit membrane, and they appeared to be multiplied by binary fission. 4. The presence of crystals unidentified in the phloem parenchyma cells was noticed by electron rnicroscopy, 5. The disease was able to be transmitted by budding, crown, and greenwood graftings to L. ovalifolium, L. obtusifolium, L, japonicum and also transmitted, even when the stocks and scions were not completely grafted. 6. Insect transmission on L. ovalifolium and L, obtzrsifolium was carried by Hishimonus sellatus. 7. The infected roots dipped in the 1,000 ppm of teracyclin solution was only temporarily effective in controlling the disease. 8. Infected plant with MLOs showed specific fluorescent reactions in phloems with DAPI stain. 9. The protein and peroxidase separated by electrophoresis showed strikingly distinctive difference between the healthy and diseased leaves.