• Microbiology and Biotechnology Letters
• /
• v.32 no.3
• /
• pp.277-281
• /
• 2004

This study was performed to investigate the antimicrobial effect of the Fraxinus rhynchophylla extracts against food-borne pathogens. First, the Fraxinus rhynchophylla was extracted with methanol at room temperatures, and fractionation of the methanol extracts from Fraxinus rhynchophylla was carried out by using petroleum ether, chloroform, and ethyl acetate, and methanol respectively. The antimicrobial activity of the Fraxinus rhynchophylla extracts was determined using a paper disc method against food-borne pathogens and food spoilage bacteria. The ethyl acetate extracts of Fraxinus rhynchophylla showed the highest antimicrobial activity against Staphylococcus aureus and Shigella dysenteriae. The synergistic effect has been found in combined extracts of Fraxinus rhynchophylla and Portulaca aleracea as compared to each extracts alone. Finally, the growth inhibition curve was determined using ethyl acetate extracts of Fraxinus rhynchophylla against Staphylococcus aureus and Shigella dysenteriae. The ethyl acetate extract of Fraxinus rhynchophylla showed strong antimicrobial activity against Staphylococcus aureus at the concentration of 4,000 ppm. The 4,000 ppm of ethyl acetate extract from Fraxinus rhynchophylla retarded the growth of S. aureus more than 24 hours and Shigella dysenteriae up to 36 hours. The ethyl acetate extracts of Fraxinus rhynchophylla has been shown the antimicrobial effect against Staphylococcus aureus and Shigella dysenteriae.

• The Korean Journal of Food And Nutrition
• /
• v.18 no.1
• /
• pp.81-87
• /
• 2005

This study was performed to investigate the antimicrobial activities of the Plagiorhegama dubium extracts against food-borne pathogens. The methanol extract was partitioned into petroleum ether, chloroform, ethyl acetate, and methanol portions. The antimicrobial activity of the P. dubium extracts was determined using a paper disc method against food-borne pathogens and food spoilage bacteria. The methanol extracts of P. dubium showed the highest antimicrobial activity against Staphylococcus aureus and Escherichia coli. The synergistic effect has been found in combined extracts of P. dubium and Hedyotis diffsa as compared to each extracts alone. Finally, the growth inhibition curve was determined using methanol extracts of P. dubium against S. aureus and E. coli. The methanol extract of P. dubium showed strong antimicrobial activity against S. aureus at the concentration of 4,000 ppm. The 4,000 ppm of ethyl acetate portion from P. dubium retarded the growth of S. aureus more than 36 hours and E. coli up to 60 hours. The methanol extracts of P. dubium has been shown the antimicrobial activity against S. aureus and E. coli.

• Journal of the Korea Society of Computer and Information
• /
• v.25 no.9
• /
• pp.159-166
• /
• 2020

The purpose of this research is to suggest some practical and policy implications for improving adolescent's self-esteem through analyzing longitudinally the effects of parental attitude, peer relationship, student-teacher relationship, school learning activity, life-goal on adolescent's self-esteem by using latent growth curve model. Analytical data was obtained from the KYCPS. The analytical results showed that the change model of adolescent's self_esteem turned out to be a leaner model in which the change rate and intercept were significant. Second, time dependent variables influence on adolescent's self_ esteem meaningfully. Third, time dependent variables influence on adolescent's self_ esteem changes significantly. This study proposed some policy implications basing on these findings.

• Korean journal of applied entomology
• /
• v.5_6
• /
• pp.27-32
• /
• 1968

The larval instar of Scintillatrix djingischani OBENBERGER WES determined by measuring the head width of the larvae, some of which were bred in the room and the other collected in orchards during four years(1963-1966). Their growth ratio and variation were also studied. 1) The variation curve of the head width of the Iarvae distinctly appeared to be seven (7) curves, which seemed to have lived to be over seven(7) instars after six(6) times of molting. 2) In general, tile larvae live out to be 6-7 instar. Those pupated at 6th instar seem to over winter in tissue from November as matured. And those pupated in late Spring or early Summer after over wintering in canbium seem to be at 7th instar. 3) The standard deviation of the head width tends to grow larger except at 1st and 7th instar, while the coefficient of variation tends to decrease according as the number of instar increases. The growth ratio was found to decrease according as the number of instar increase except at 1 at and 2 nd instar. 4) To the growth of tee larval head width of this insect, Games and Campbell's formula was more applicable than Dyar's. 5) From the activties of larvae it is presumed that those bred in the year over winter in phelloderm or canbium at the 2 nd-3 rd instar, and the matured (2 year old) emerge the next year after over wintering in cambium or tissue at the 5th or 6th instar.

• The Korean Journal of Food And Nutrition
• /
• v.14 no.6
• /
• pp.548-561
• /
• 2001

Listeria spp. from sea water, fishes and shellfishes have been troubled in many countries. So we exam ined its distribution rates, biochemical characteristics of a separated strain, growth curve of pH at set times to 4 species of standard strain, and yes or no of growth inhibition for precautionary measure of food poisoning by L. monocytogenes, garlic, mustard, wasabi, and green tea extracts including sensitivity of antibiotics 10 species. As its results, check numbers of its positivity to Listeria spp. were 32 species in total examination body 200 species, and its isolation rates were 16%, L. innocua was 14.0%, L. monocytogenes 1.0%, and L. seeligeri 1.0% by the strain species. All the standard strain of 4 species showed growth inhibition bellow pH 3.0, its pH conditions of the optimum growth at 7.0∼8.0, and its growth was more active in alkali co]tuition than in acid condition. Its growth inhibition examination by garlic extracts had an the worst effects with O.D values of 0.078∼0.210. But the case of mustard and wasabi had weakened effect, and the case of green tea had some effect as the time went by. The results of sensitivity examination of antibiotics 10 species were as fellows. L. innocua of the 16 cases showed sensitivity of 100% in all 5 species, Ampicillin, etc, and Ciprofloxacin showed sensitivity of 43.7% and gentamicin, 93.7%. But tetracycline showed tolerance of 31.3% , cefotaxine. 75%, nalidixic acid, 100%. L. monocytogenes of the 6 cases showed sensitivity of 100% in all 6 species, ciprofloxacin, etc.

• Korean Journal of Food Science and Technology
• /
• v.33 no.5
• /
• pp.574-581
• /
• 2001

The microbial properties and acid tolerance of the three kinds of Acetobacter sp. isolated from persimmon vinegar were investigated. Acid tolerance was also evaluated. Acetobacter sp. were gram negative, short rod, nonspore forming and motile. They reacted positively catalase, methyl red, oxidation fermentation, Voges-Proskauer and nitrate reduction tests and negative to hydrogen sulfide test and ONPG. Acetobacter sp. showed normal growth curve in Carr broth and there was no significant difference between isolates and (standard on) typical strains such as Acetobacter aceti (KCTC1010), Acetobacter liquefaciens (KCTC2804), Acetobacter diazotrophicus (KCTC 2859). Optimum temperature and initial ethanol concentration in incubation were $30^{\circ}C$ and 6%, respectively. Growth and acid production of Acetobacter sp. were suppressed by the concentration of above 4% acetic acid. The amount of $Mg^{++}$ release from Acetobacter sp. cells in medium was increased by acetic acid, and almost in the concentration of 6% acetic acid. Glycolysis by Acetobacter sp. had optimal pH about 6.0 to 7.0 and more stable in acidic condition than in alkalic. The $H^+-ATPase$ of Acetobacter sp. S-1 and S-3 showed a maximal activity between pH values of approximately 5.5 to 7.5 and 6.0 to 7.5, respectively.

• Journal of the Korean Vacuum Society
• /
• v.13 no.1
• /
• pp.9-13
• /
• 2004

Perylene is an interesting material known to have P-type and N-type characteristics at the same time. We prepared perylene thin-films in ultrahigh vacuum with two different deposition rates of 0.1 $\AA$/s and 1.0 $\AA$/s in order to study the dependence of film characteristics on the growth condition. The smaller average grain size with larger surface coverage as well as the better crystallinity were observed on the perylene film prepared under 1.0 $\AA$/s deposition rate in x-ray diffraction (XRD) and atomic force microscopy (AFM) study. For studying electrical property of the film, perylene organic thin-film transistor (OTFT) with gold contacts was fabricated on $SiO_2$/Si surface in UHV condition. The prepared perylene OTFT device shows P-type characteristic. The obtained hole mobility in the current-voltage characteristic curve was$2.23\times10^{-5}\textrm{cm}^2$/Vs.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.10 no.6
• /
• pp.937-946
• /
• 1986

In this paper, the plane stress fracture toughness of low carbon steel with 3mm thickness is investigated for various specimen widths and crack ratios using the J integral. The experiments is carried out for the compact tension(CT) specimen on an Instron machine. For materials that may be approximated by the Ramberg and Osgood stress strain law, the relevant crack parameter like the J integral and load line displacement are approximately normalized. Crack driving forces in terms of J integral is computed using the above estimation scheme. Abtained results are summarized as follows. (1) The plane stress fracture toughness, J$_{c}$, is almost constant in the range 50-70mm of width. Hence J$_{c}$ can be obtained by using smaller specimen than ASTM standard. (2) Yoon's and Simpson's formular which considers crack growth in obtaining J integral show more consevative J than Rice's and Merkle's (3) J$_{c}$ is almost constant in the range 0.499-0.701 crack ratios tested. J$_{c}$ obtained by using Kumar's formular is 28.14kgf/mm for base metal specimen and 32.51kgf/mm for annealed. (4) Comparison of the prediction with actual experimental measurements by Yoon's formular show good agreement for several different-size specimens.

• Journal of Digital Convergence
• /
• v.16 no.9
• /
• pp.107-114
• /
• 2018

Since China's economic reform in 1978, international trade has enormously flourished and the port industry is reckoned as a key factor contributing to this growth. This study examines the Bohai Rim port group in the scope of top three largest ports Qingdao, Dalian and Tianjin. By utilizing indicators including concentration ratio (CR), Herfindahl-Hirschman index (HHI), the Gini coefficient and the Lorenz curve as well as shift-share analysis (SSA), the concentration level of this port group in the period 2004-2016 is discussed. As a results, CR demonstrates a decrease during the studied period with a minor fluctuation, and HHI index shows a trend of deconcentration with Bohai Rim port group. In addition, SSA indicates that during the period 2004-2016, the overall shift index of Qingdao port was -1.371 meanwhile with Tianjin and Dalian port were 0.118 and 1.252 in turn. These results suggest that the growth in regional influence of Tianjin and Dalian ports would motivate to the deconcentration pattern in Bohai Rim region. The findings assist decision makers and scholars to obtain knowledge about the port development this region. Considering the geographic position of these three ports as the gate of northeast China, it is suggested that these three ports could explore their advantages and cooperate with the small ports in the surrounding area to enhance their influences in the future study.

• Journal of Embryo Transfer
• /
• v.22 no.3
• /
• pp.143-147
• /
• 2007

Records on 546 Korea native pigs for average daily gain (ADG), age at 70 kg (D70 kg) and backfat thickness (BF) made between 2001 and 2006 in herds on National Institutes of Animal Science in Korea were used to estimate genetic parameters. The data was analyzed by the DF-REML (Derivative-Free Restricted Maximum Likelihood) program of Boldman using a single-trait animal model. Heritabilities were 0.26, 0.09, and 0.29 for ADG, D70 kg and BF, respectively. The phenotypic correlations of ADG with D70 kg and BF were -0.71 and 0.30. The phenotypic correlation of D70 kg with BF was -0.15. The genetic correlations of ADG with D70 kg and BF were -0.11, 0.41, respectively. The genetic correlation of D70 kg with BF was -0.16. The data of weights and measurements on body length, body height and chest width after age at 11 months (days to 330) were shown scarcely less differences compare to data of age at 11 months.