• Journal of Veterinary Clinics
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• v.21 no.2
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• pp.129-132
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• 2004

Causative agents of mastitis were isolated from glandular tissues of 101 culled Holstein cow udders and tested with antimicrobials by standardized disc diffusion method. Pathogens most commonly isolated were coagulase-negative staphylococci (43.9%) and streptococci (21.4%). Most of the udders (88.5%) showed mixed infections with more than two species of bacteria. Antimicrobial sensitivity tests revealed that 90.0% and 84.5% of the isolated organisms were susceptible to amoxicillin and gentamicin, while most organisms were resistant to erythromycin. Coliforms were resistant to ampicillin, cephalothin, cefazolin, erythromycin, kanamycin, neomycin, penicillin and tetracycline and streptococci to erythromycin, kanamycin, neomycin, trimethoprim/sulfamethoxazole and tetracycline.

• Journal of Applied Biological Chemistry
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• v.48 no.4
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• pp.167-169
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• 2005

Crude extract of bioconverted linoleic acid using Pseudomonas aeruginosa PR3 was evaluated for its antibacterial activity against food-borne pathogenic bacteria. Crude extract showed antibacterial activity against four Gram-positive bacteria, Staphylococcus aureus (ATCC 6538), S. aureus (KCTC 1916), Listeria monocytogenes (ATCC 19166), and Bacillus subtilis (ATCC 6633), and one Gramnegative bacterium, Pseudomonas aeruginosa (KCTC 2004), with minimum inhibitory concentrations ranging from 750 to $1,500\;{\mu}g{\cdot}ml^{-1}$. S. aureus and B. subtilis were selected for growth inhibition assays with bioconverted linoleic acid. Major antibacterial effects occurred at lag phase.

• Journal of Veterinary Clinics
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• v.20 no.2
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• pp.166-171
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• 2003

Milk samples were collected from a total of 418 quarters of 214 Holstein cows. Of these, samples which were positive on California Mastitis Test (CMT) and above 200,000 cells/ml by somatic cell counts were subjected to bacteriological examination and antimicrobial susceptibility test. Major pathogens responsible for mastitis included coagulase-negative staphylococci (34.3%), coagulase-positive staphylococci (21.5%), gran-negative rod (coliforms and noncoliforms: 12.6%) and Streptococcus spp. (8.4%). These strains were tested with 13 antimicrobial agents by the Kirby and Bauer standardized disc diffusion method. The isolated pathogens were mostly susceptible to amoxicillin and cephalothin, but were resistant to erythromycin.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.139-142
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• 2004

Nickel base superalloys are widely used for high temperature applications due to heat resisting capability and corrosion resistance at high temperatures. Superalloys with many strengthening alloying elements are frequently used in powder form to alleviate harmful effects of alloy segregation. HIP (hot isostatic pressing) and DB (diffusion bonding) as a form of solid-state bonding process is used to make turbine components, such as integrated turbine rotors. HIP/DB process requires many technical overcomes related to dimensional changes as well as microstructural control. In this research, HIP/DB process for nickel base superalloys, Udimet 720 and MM 247, were investigated with a view to control the dimensional change during the consolidation process. Simple disc-shaped cans were used to select the conceptual die design for the control of the dimensional change especially in radial direction. The change in the shape of consolidated shape was investigated using commercial FE code with constitutive equations fur low temperature plasticity deformation.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.777-780
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• 2000

Propolis는 꿀벌이 다양한 식물로부터 모아온 수지상의 물질이며 꿀벌의 분비물과 수목의 삼출액 등의 다양한 형태를 함유하고 있다. Propolis는 고대로부터 항생작용과 상처치유에 효과적인 혼합물로 알려져 있다. 또한 에탄올 추출 Propolis는 항박테리아, 항미생물, 항곰팡이, 마취성, 항염증, 통증저하, 면역상승과 세포증식억제작용 특성과 같은 약물학적 활성을 나타낸다고 알려져 있다. 이 연구에서는 국내산 Crude Propolis로부터 얻어진 EEP의 첨가가 미생물의 성장에 미치는 영향을 조사하였다. Paper Disc Diffusion Method와 균주의 성장에 따른 저해 정도를 확인하기 위한 20mg EEP/100mL MH배지에서도 균주의 성장을 저해함을 확인할 수 있었다. 70% EEP와 95% EEP에서 모두 저해를 확인할 수 있었고95% EEP에서 저해활성이 더 좋았다.

• Ceramist
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• v.22 no.3
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• pp.301-315
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• 2019

We prepared hybrids between layered double hydroxide (LDH) and natural plant extract such as Peaonia suffruticosa Andrews (PS) and Peaonia Japonica (PJ) which was confirmed anti-bacterial activity through paper disc diffusion assay. According to X-ray diffractometer, scanning electron microscope, zeta-potential measurement and quantification of extract loading amount in hybrids, we confirmed that similar amount of PS and PJ loaded on inter-particle pore of LDH with partial adsorption on surface of LDH through reconstruction process. We also evaluated the bacterial colony forming inhibition of PS extract, PJ extract, PS-LDH and PJ-LDH hybrids against Escherichia coli as gram negative bacterium and Bacillus subtilis as gram positive bacterium, suggesting that both hybrids have enhanced anti-bacterial activity compared with extract itself.

• Mycobiology
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• v.37 no.1
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• pp.31-36
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• 2009

A phytochemical study on the flower of Calotropis gigantea (Linn.) using silica gel column chromatography and preparative thin layer chromatography, led to the first time isolation of Di-(2-ethylhexyl) phthalate (compound 1) and anhydrosophoradiol-3-acetate (compound 2). The structures of these compounds were confirmed by spectroscopic analyses (IR, HRTOFMS and NMR). The antibacterial and antifungal activities of ethyl acetate extract, compound 1 and compound 2 were measured using the disc diffusion method. Ethyl acetate extract and compound 1 presented better results than compound 2. The minimum inhibitory concentrations (MICs) of the extract and compounds were found to be in the range of $16{\sim}128{\mu}g/ml$. The cytotoxicity ($LC_{50}$) against brine shrimp nauplii (Artemia salina) were also evaluated and found to be 14.61 ${\mu}g/ml$ for ethyl acetate, 9.19 ${\mu}g/ml$ for compound 1 and 15.55 ${\mu}g/ml$ for compound 2.

• Korean Journal of Microbiology
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• v.16 no.4
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• pp.161-169
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• 1978

Escherichiae-like organisms were isolated from rectal specimens of 56 children who were either in preschool age or in elementary school. The isolated strains were subjected to tests to screen enteropathogens producing heat-labile enterotoxin and susceptibility test to various antibiotics by disc diffusion method on agar plates. Production of heat-labile enterotoxin by the strains was assyed in the sensitive and reproducible cultured adrenal tumor cell system. The assay was sterodogenesis of the cell in the presence of heat-labile enterotoxin. Among 56 strains, gave positive reaction in the test of toxin production. This meant that about 10% of the children population objected to the study harbored the toxigenic strain of enteropathogenes. Some of these toxigenic strains were resistant to the antibiotics employed in the test. This study suggested that considerable population in Korea may harbor entertoxigenic E. coli as a part of intestinal normal flora. The toxigenic strains which are resistant to antibiotics may bring issue of public health in the future.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.171-174
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• 2004

Superalloys with many strengthening alloying elements are frequently used in powder form to alleviate harmful effects of alloy segregation. HIP (hot isostatic pressing) and DB (diffusion bonding) as a form of solid-state bonding process is often used to make turbine components, such as integrated turbine rotors. HIP/DB process requires many technical overcomes related to dimensional changes as well as microstructural control. In this research, HIP/DB process for nickel base superalloys, Udimet 720, were investigated with a view to control the dimensional change during the consolidation process. Simple disc-shaped cans were used to select the conceptual die design for the control of the dimensional change especially in radial direction. The change in the shape of consolidated shape was investigated using commercial FE code with constitutive equations for low temperature plasticity and creep deformation.

• Korean Journal of Pharmacognosy
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• v.32 no.2 s.125
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• pp.140-144
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• 2001

The composition of essential oils in the leaves of three cultivars (Ban-Chung-Gat, Chung-Gat and Dolsan-Gat) of Brassica juncea L. were analyzed and their antifungal activity were investigated in this study. Allyl isothiocyanate, 2-phenyl ethyl isothiocyanate, 4-isothiocyanato-1-butene, 5-methyl isothiazole, benzene acetaldehyde, benzene propane nitrile and beta-ionone have been identified in all of the experimented oils. The main component of the oils from Ban-Chung-Gat and Chung-Gat was 2-phenyl ethyl isothiocyanate while allyl isothiocyanate was the representing compound in the oil of Dolsan-Gat. The antifungal activities of the oils were tested by micro broth dilution method and disc diffusion method. As the result the oils exhibited significant inhibiting activities against Aspergillus niger, A. flavus, Trichoderma viride, Candida albicans, C. utilis, C. tropicalis, Cryptococcus neoformans, Trichosporon mucoides, Trichophyton tonsurans and Geotrichum capitatum.