• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.6
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• pp.521-527
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• 2016

This paper is concerned with the numerical analysis of dynamic response of floating offshore wind turbine subject to underwater explosion using an effective non-reflecting technique. An infinite sea water domain was truncated into a finite domain, and the non-reflecting technique called the perfectly matched layer(PML) was applied to the boundary of truncated finite domain to absorb the inherent reflection of out-going impact wave at the boundary. The generalized transport equations that govern the inviscid compressible water flow was split into three PML equations by introducing the direction-wise absorption coefficients and state variables. The fluid-structure interaction problem that is composed of the wind turbine and the sea water flow was solved by the iterative coupled Eulerian FVM and Largangian FEM. And, the explosion-induced hydrodynamic pressure was calculated by JWL(Jones-Wilkins-Lee) equation of state. Through the numerical experiment, the hydrodynamic pressure and the structural dynamic response were investigated. It has been confirmed that the case using PML technique provides more reliable numerical results than the case without using PML technique.

• Journal of Sericultural and Entomological Science
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• v.25 no.2
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• pp.1-31
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• 1984

Flacherie, as one of the most prevalent silkworm diseases, causes severe economic damage to sericultural industry and its pathogens have been proved to be flacherie virus (FV) and densonucleosis virus (DNV). Multiplications of the viruses in the larvae of the silkworm, Bombyx mori, were studied by the sucrose density gradient centrifugation and electron microscopy. The quantitative and qualitative changes of nucleic acids and proteins were investigated from the midgut and hemolymph in the silkworm larvae infected separately with FV and DNV. The histopathological changes of epithelial cells of infected midgut also were examined by an electron microscope. 1. Purified fractions of FV or DNV in a sucrose density gradient centrifugation yielded one homogenous and sharp peak without a shoulder, suggesting no heterogenous materials in the preparation. Electron microscopy also revealed that FV and DNV were spherical particles, 27nm and 21nm in diameter, respectively. 2. Silkworm larvae showed a decrease in body weight on the 6th day and in midgut weight on the 3rd day after inoculation with FV or DNV. 3. DNA content was higher in the midgut when infected with FV or DNV, but the hemolymph of the infected larvae showed no difference during first 6 days after inoculation, after which DNA concentration declined rapidly. 4. RNA synthesis of silkworm larvae infected separately with FV and DNV was stimulated in the midgut, but RNA content was reduced in the hemolymph at the early stage of virus multiplication. At the late stage of virus multiplication, however, it was extremely reduced in both midgut and hemolymph. 5. The concentration of protein in the midgut and hemolymph of silkworm larvae infected separately with FV and DNV showed no difference from that of the healthy larvae at the early stage of virus multiplication, but it was significantly reduced at the late stage of virus multiplication. 6. There was no difference in the electrophoretic patterns of RNAs extracted from the midgut of healthy or virus-infected larvae. 7. The electrophoresis of proteins extracted from the midgut infected with FV or DNV, when carried out on the 1st and 5th day after virus inoculation, showed no difference from that of the healthy larvae. But, there was an additional band with medium motility in the proteins on the 8th day after virus inoculation, while a band with low mobility shown in the proteins of healthy larvae disappeared in the infected larvae. However, a band with high mobility in the healthy larvae was separated into two fractions in the infected larvae. 8. The electrophoretic pattern of hemolymph proteins of the silkworm larvae infected separately with FV and DNV was similar to that of the healthy larvae, but the concentration of hemolymph proteins in the infected larvae was lower than that of the healthy larvae at the late stage. 9. Two types of inclusion bodies were shown by the double staining of pyronin-methyl green in the columnar cell of the midgut on the 8th day after FV inoculation. 10. Electron microscopy of the infected midgut revealed that the 'cytoplasmic wall' of the goblet cell thickened on the 5th day after FV inoculation and several types of the cytopathogenic structures, such as virus$.$specific vesicles, virus particles, linear structures, tubular structures, and high electron-dense matrices were observed in the cytoplasm of the goblet cell. The virus particles were also observed in the microvilli and the structures similar to spherical virus particles were observed around the virus-specific vesicles, suggesting the virus assembly in the cytoplasm. 11. Fluorescence micrograph of the infected midgut stained with acridine orange showed that the nucleus, the site of DNV multiplication in the columnar cell, enlarged on the 5th day after virus inoculation. 12. Electron microscopic examination of DNV infected midgut revealed that the nucleolus of the columnar cell was broken into granules and those granules dispersed into apical region of the nucleus on the 5th day after virus inoculation. On the 8th day after inoculation, it was also observed that the nucleus of the columnar cell was full with the high electron-dense virogenic stroma which were similar to virus particles. These facts suggest that the virogenic stroma were the sites of virus assembly in the process of DNV multiplication.

• The Korean Journal of Mycology
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• v.16 no.4
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• pp.220-225
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• 1988

This study was carried out to investigate the effect on the system of crop rotation of sesame(Sesamum indicum L). The results of infected plant percentage and yield of sesame wilting disease, fluctuation of density of Fusarium oxysporum and Actinomycetes, and their pathogenicity test on Fusarium spp isolated from sesame cultural soil were investigated. Density of F. oxysporum was the highest in a sesame continuous cropping soil but that of Actinomycetes was the lowest in that soil. And that of F. oxysporum and Actinomycetes according to investigation date was the highest at June. 30 and July. 30, respectively. Their pathogenicity of F. oxysporum and F. solani isolated from sesame cultural soil to sesame, peanut and green gram were recognized to all isolates except one isolate among F. oxysporum 8 isolates and one isolate to sesame, 2 isolates to peanut and all isolates to green gram among F. solani 4 isolates. F. oxysporum density and infected plant of wilting disease were increased as a result of replanted cultivation of sesame, and yield of that was prominantly reduced. Relation between density of F. oxysporum in cultural soil and infected plant percentage showed positive correlation and yield index highly negative. There was little difference between sesame-upland rice and sesame-peanut in the system of crop rotation.

• Journal of Food Hygiene and Safety
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• v.22 no.2
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• pp.82-87
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• 2007

This research was performed to investigate chemical and microbiological hazards of Ready-to-eat(RTE) compound foods which uses the by-product of meat. For this experiment, 51 samples of RTE compound foods in by-product of meat distributed in Incheon from January to December 2006 were tested. The contents of heavy metals in the main ingredient of RTE compound foods were in the range of $0.073{\sim}0.112ppm$ for lead (Pb), $0.006{\sim}0.013ppm$ for cadmium (Cd) and $0.746{\sim}0.978ppb$ for mercury (Hg). The concentrations of residual ABS(alkyl benzene sulfate) in the small intestine which is a main ingredient of Gopchang-casserole were $$0.8ppm{\sim}57.6ppm$ (Ave. 10.3ppm). Staphylococcus aureus was isolated from 11 samples (21.6%) among 51 main ingredients of RTE compound foods. The isolation rates of Salmonella spp. and Clostridium perfringens were 2.0% (1/51) and 5.9% (2/51), respectively. By types of main ingredient, the small intestine was showed the highest isolation rate as 35.3% (12/34), ham and the sausage which are main ingredients of the Budae-pot stew were 25% (2/8) and other meat products were 20% (1/5). Food poisoning bacteria was not found in the blood of pig which is a main ingredient of the Sunji-pot stew. 28.4% (27/95) of sauce included in each RTE compound foods were coliform bacteria positive. Pesticide residues were found in four of 45 vegetables which are the additional ingredient of RTE compound foods. The concentrations of pesticide were chlorothalonil 2.8 ppm, EPN 10.3 ppm, chlorpyrifos 0.4ppm and indoxacarb 0.7ppm. In 33 bean sprout samples, captan and carbendazim were not detected.

• Journal of Marine Life Science
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• v.8 no.2
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• pp.136-149
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• 2023

Basic bioactivities (antioxidant, anti-inflammatory, antibacterial, anticancer, antiviral) were investigated from 370 strains of marine bacteria, fungi, and microalgae obtained from various marine environmental regions in Korea, and the activity results were obtained at the collection site, isolation source, and species level was compared. In the case of marine bacteria, strains belonging to the generally useful genera Streptomyces and Bacillus were observed to have particularly strong efficacy and useful resources were mainly isolated from marine sediments. In the case of marine fungi and microalgae, results showing strong species-specific activity were confirmed, and results showing efficacy-specific activity were also obtained. Based on these results, it is a research result that can facilitate priority access as a strategic material for industrial revitalization and the establishment of a strategy to secure resources based on usefulness when conducting research on chemicals that are selectively effective against specific diseases or when conducting resource-based research. In addition, we believe that by using these results as material for sale through the Marine BioBank (MBB), academia and industry can use them to help accelerate the revitalization of the marine bio industry.

• Journal of Korean Society of Forest Science
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• v.106 no.3
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• pp.288-299
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• 2017

This study was conducted to find out the influence of drought stress on physiological responses of Synurus deltoides. Drought stress was induced by withholding water for 25 days. Leaf water potentials were decreased of both predawn (${\Psi}_{pd}$) and mid-day (${\Psi}_{mid}$) with increasing drought stress, but water saturation dificit (WSD) was 7 times increased. ${\Psi}_{pd}-{\Psi}_{mid}$ showed the significant difference of 0.22~0.18 MPa in stressed before 10 days, and nonsignificant as treatment time became longer. A strong reduction of stomatal conductance ($gH_2O$) and stomatal transpiration rate (E) were observed after 15 days of drought stress Significant reductions of net apparent quantum yield (${\Phi}$) and maximum photosynthesis rate ($Pn_{max}$) were observed after 20 days of drought stress; However, water use efficiency (WUE) was shown the opposite trend. This implies that decrease of photosynthesis rate may be due to an inability to regulate water and $CO_2$ exchanged through the stomata. From JIP analysis, flux ratios (${\Psi}_O$ and ${\Phi}_{EO}$) and performance index on absorption basis ($PI_{ABS}$) were dramatically decreased withholding water after 15 days, which reflects the relative reduction of photosystem II activity. The leaf of S. deltoides showed osmotic adjustment of -0.35 MPa at full turgor and -0.40 MPa at zero turgor, and also cell-wall elastic adjustment of 9.4 MPa, indicating that S. deltoides tolerate drought stress through osmotic adjustment and cell-wall elastic adjustment. The degree of change in water relations parameters such as Vo/DW, Vt/DW decreased with increasing drought stress. This result showed that S. deltoides was exhibited a strong reduction of photosynthetic activity to approximately -0.93 MPa of predawn leaf water potential, and both of osmotic adjustment and cell-wall elastic adjustment in drought stress condition appears to be an important adaptation for restoration in this species.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.11
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• pp.1717-1726
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• 2013

Fermentation characteristics and health functionalities of kimchi by inoculating kimchi lactic acid bacteria (LAB) starters were studied. We manufactured single LAB starter kimchi (Lactobacillus plantarum pnuK, Lactobacillus plantarum 3099K, Leuconostoc mesenteroides pnuK), mixed LAB starter kimchi (Lb. plantarum pnu/Leu. mesenteroides pnuK, Lb. plantarum 3099/Leu. mesenteroides pnuK) with inoculum size of $10^6$ CFU/g, as well as naturally fermented kimchi (NK), and fermented them for 6 days at $15^{\circ}C$. The pH and acidity of the early phase of fermentation were not different, but kimchi with the starters showed rapid changes in the pH and acidity from 2 days of fermentation. As the fermentation progressed, the level of total aerobic bacteria and Lactobacillus sp. increased similarly with or without Lb. plantarum (LP) inoculation. However, the level of Leuconostoc sp. was high in kimchi inoculated with Leuconostoc sp. starter. In the sensory evaluation test, kimchi with starters received higher overall acceptability scores than those of NK; mixed starter added kimchi earned the highest score. In DPPH and hydroxyl radical scavenging activity, kimchi with the starters exhibited higher activity than that of NK. In the MTT assay of HCT-116 and HT-29 human colon cancer cells, NK showed inhibition rates of 63.4 and 51.9%, but LPpnuK achieved 77.1 and 68.8%, respectively. This study showed that inoculating starters in kimchi increased in vitro antioxidant and anticancer activities, and single starter (LP) added kimchi revealed higher functionality than the kimchi with mixed starter. Kimchis with the starters effectively up-regulated the gene expressions of the pro-apoptotic gene of Bax, but down-regulated Bcl-2. They promoted expressions of p53 and p21, and suppressed expressions of inflammation-related genes, iNOS and COX-2, compared with NK. Taken together, it is expected that using starters may help manufacture kimchi with improved sensory quality and health functionality.

• Research in Plant Disease
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• v.16 no.3
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• pp.238-246
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• 2010

In 2006 fall, a preliminary survey of viruses in two important medicinal plants, Cynanchum wilfordii and C. auriculatum, was conducted on the experimental fields at the Agricultural Research and Extension Services of Chungbuk province in Korea. On each experimental fields, percentage of virus infection was ranged from 20 to 80%, and especially an average of disease incidence propagated by roots was twice higher than that by seeds. The various symptoms were observed in Cynanchum spp. plants, such as mosaic, mottle, necrosis, yellowing, chlorotic spot and malformation etc. In electron microscopic examination of crude sap extracts, filamentous rod particles with 390-730 nm were observed in most samples. The virus particles were purified from the leaves of C. wilfordii with typical mosaic symptom, and the viral RNA was extracted from this sample containing 430-845 nm long filamentous rod. To identify the viruses, reverse transcription followed by PCR with random primers was carried out. The putative sequences of P3 and coat protein of potyvirus were obtained. From a BLAST of the two sequences, they showed 26-38% and 62-72% identities to potyviruses, respectively. In SDS-PAGE analysis, the subunit of coat protein was approximately 30.3 kDa, close to the coat protein of potyvirus. In bioassay with 21 species in 7 families, Chenopodium quinoa showed local lesion on inoculated leave and chlorotic spot on upper leave, but the others were not infected. RT-PCR detection using specific primer of C. wilfordii and C. auriculatum samples, all of 24 samples with virus symptom was positive, and five out of seven samples without virus symptom were also positive. On the basis of these data, the virus could be considered as a new member of potyvirus. We suggested that the name of the virus was Keunjorong mosaic virus (KjMV) after the common Korean name of C. wilfordii.

• Journal of Sericultural and Entomological Science
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• v.26 no.2
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• pp.11-15
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• 1984

To save the labour reguired for separation of copulated moth during egg Production, some of the chemicals available at the market were on screen test for easy separation of copulated moth of silkworm. The obtained results are summarized as following. 1. In a separation ratio of copulated moth along with a treating time, TCTFE(Trichloro-trifluoroethane) completely separated the copulated moth in 10 minutes. The combinations of TCTFE plus Acetone (87.5 : 12.5 V/V) and TCTFE plus Acetic acid (50 : 50 V/V) take 25minutes for the complete separation of copulated moth. Use of Acetic acid solution only makes 100% separation of copulated moth in one hour and foully minutes and non$.$treatment shows only 47.5% of separation in three and half hours. On the other hand. There is no statistical significance between TCTFE Plus Acetone and control in the egg productivity. 2. The combination of TCTFE Plus Acetone (87.5 : 12.5 V/V) does not infuluence the egg productivity of the moth, showing 443 grains for an average number of egg per moth out of which 417 grains are for the number of fertilized eggs while control shows 452 grains for an avarage number of egg/moth and 428 grains for the number of fertilized eggs. However a sing1e use of TCTFE and Acetic acid shows less egg productivity and number of ferilized eggs per moth, respectively as compared to those of the control. In particular, a single use of acetic acid makes an increase of number of non-egg prodncible moth and it seems to be brought due to a chemical damage. 3. In a rearing test of the egg laid by the chemical treated moth, there are no differences among the treatments in all of the useful characters of the larvae; larval duration, survival rate, cocoon yield, single cocoon weight, single cocoon shell weight and cocoon shell ratio. In these regards, it is recognized that TCTFE can be practically used for the separation of copulated moth and the combination of TCTFE and Acetone promote its efiectiveness on the separation of copulated moth.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.215-223
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• 1978

In Korea, the annual production of watermelon and cantaloupe melon is around 110,000 to 170,000 Metric Tons, and as the fruit does not keep well, studies were conducted to determine the feasibility of preservation in the form of natural juice or lactic fermented juice. The results obtained in these studies are summarized as follows: (1) The average yield of juice obtained from watermelon was 56.2%, and from cantaloupe melon 65.8%, of the fresh weight. (2) The colloidal components of watermelon juice separated from the juice by sedimentation within 24 hours. Cantaloupe melon juice gave a stable colloidal dispersion. (3) No change in the colour of the juices was detected by sensory evaluation or instrumental methods after they were treated at $100^{\circ}C$ for 5 minutes. (4) The addition of canesugar to give a total solids content of 11/13 Brix gave juices which were preferred by most tasters. (5) Lactic fermentation of natural juices pasteurised at $90^{\circ}C$ for 5 minutes, and inoculated with a pure culture of lactic acid bacteria proceeded without interference from competing microorganisms. (6) Sensory evaluation of lactic fermented juices indicated that 60% of tasters found the juices as acceptable or better than commercial fruit nectars at present on the market. (7) Taste panels showed a preference for natural melon juices over the lactic fermented juices. (8) The peroxidase activity of cantaloupe melon juice was higher than that of watermelon juice, with juice extracted from the core of the fruit showing a higher activity than that from other portions of the tissue. (9) Two types of peroxidase, of differing heat stability were detected in both juices. The more heat stable peroxidase had a decimal reduction time of 40 minutes at $80^{\circ}C$ and a z value of $11^{\circ}C$.