• 한국임상수의학회지
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• 제32권2호
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• pp.158-161
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• 2015

세균성 피부염은 항생제 치료가 필요한 흔한 질환이다. 최근 항생제 내성 세균이 전 세계적으로 증가하고 있는 추세이다. 본 연구에서는 개 피부염 병변에서 분리한 S. pseudintermedius의 항생제 내성 유전자 발현을 조사하고, 이를 디스크 감수성 시험결과와 비교하였다. 총 7개의 S. pseudintermedius 균주가 연구에 포함되었다. 세균 동정은 16S rDNA 염기 서열 분석으로 실시하였다. 조사 결과 분리한 S. pseudintermedius 모두가 1개 이상의 항생제 내성유전자(mecA, blaZ and aac[6']/aph[2"])를 보유하였다. 전체 분리균주가 blaZ 유전자에 양성을 보였으나, 두 개 균주만이 amoxicillin/clavulanate에 내성을 나타냈다. Gentamicin 내성을 나타낸 5개 균주 중, 1개는 aac(6')/aph(2") 유전자에 대한 PCR 검사에서 음성을 나타냈다. 이 결과는 내성 유전자 검출 PCR 기법과 디스크 감수성 시험 기법이 항생제 내성을 검사하는 데에 있어 상호보완적인 관계를 가짐을 제시한다.

• 한국수산과학회지
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• 제52권4호
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• pp.382-388
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• 2019

Streptococcosis caused by Streptococcus parauberis is a very important disease in farmed olive flounder Paralichthys olivaceus. For most fish pathogens, including S. parauberis, there are no analytical criteria to distinguish antibioticsusceptible strains from antibiotic-resistant strains. In this study, epidemiological cut-off ($CO_{WT}$) values were generated to classify 75 strains of S. parauberis isolated from 1999 to 2018 as wild type (WT) and non-wild type (NWT) using disc diffusion data and normalized resistance interpretation (NRI) analysis. The susceptibility of the isolates to 16 antibiotics was evaluated using CLSI guideline M42-A. The wild-type cut-off values for amoxicillin, erythromycin, oxytetracycline, and florfenicol for S. parauberis were ${\geq}35$, 31, 28, and 27 mm, respectively. The NWT ratios of S. parauberis strains to treatment with GEN, FFC, ENR, SXT, EFT, VAN, and CHL were 17% or less, indicating that these antibiotics may be used to treat streptococcosis caused by S. parauberis. For recent S. parauberis isolates, the NWT ratios for AMX, ERY, OTC and FFC are much higher than for strains isolated from 1999-2007. The $CO_{WT}$ data from this study will assist aquatic animal disease professionals in prescribing appropriate antibiotics for the treatment of streptococcosis caused by S. parauberis, which will help reduce the misuse and abuse of antibiotics in the aquaculture sector.

• 생명과학회지
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• 제29권7호
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• pp.785-791
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• 2019

본 연구에서는 편백나무(Chamaecyparis obtusa) 추출액의 항산화 활성 및 항균활성을 검토하였다. 편백나무 추출액의 항산화 활성을 평가하기 위하여 DPPH radical 소거능, ABTS radical 소거능 및 SOD 유사 활성을 분석하였다. 그 결과, 편백나무 추출액의 DPPH radical 및 ABTS radical 소거 활성은 농도 의존적으로 증가하였으며, $50{\mu}l/ml$ 농도에서 78% 및 62%의 최대 활성을 나타내었다. 또한, 편백나무 추출액은 높은 SOD 유사 활성을 보였으며, $50{\mu}l/ml$ 농도에서 92.85 %의 최대 활성을 나타내었다. 한편, 편백나무 추출액의 항균 활성을 측정하기 위해 Paper disc agar diffusion 법을 이용하여 식중독 및 질병을 일으키는 6종의 균주에 대하여 검토하였다. 편백나무 추출액은 B. cereus, E. coli, L. monocytogenes, S. aureus, S. typhi, V. parahaemolyticus에 대한 항균 활성이 나타났고, 이중 B. cereus에 대하여 가장 강한 항 박테리아 활성을 보였다. 이상과 같이 항균 활성이 나타난 6종의 균주에서 편백나무 추출액의 MIC 및 MBC는 $30{\sim}40{\mu}l/ml$로 확인되었다. 이러한 결과는 편백나무 추출액을 이용하여 식중독과 같은 병원균의 성장을 억제하는 항균 소재로 개발한다면 산업적 가치가 높을 것으로 생각된다.

• Journal of Electrochemical Science and Technology
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• 제3권4호
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• pp.165-171
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• 2012

An experimental study of mass transfer to an amalgamated copper rotating disc electrode has been employed to determine an empirical correlation for the mass transfer rate in laminar flow. The study was performed in a three-electrodes configuration using 0.1 M boric acid and 0.1M potassium chloride as supporting electrolyte with Zn (II) concentration in the range (25-100 mg $dm^{-3}$). Polarization curves at different zinc ion concentration are reported. Hydrogen and oxygen reduction has also been considered.The diffusion coefficients and mass transfer coefficient were obtained using limiting diffusion current technique based on zinc ion reduction. A least squares analysis indicates that the laminar flow results for 13067 < Re > 57552 and 550 < Sc > 1390 can be correlated by the following equation with correlation coefficient (CR) equal to 0.98: $sh=0.61Re^{0.5}Sc^{1/3}$.

• 한국동물위생학회지
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• 제36권4호
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• pp.297-301
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• 2013

The present study was to investigate anti-microbial effects of curcumin on major bacterial pathogens for farmed fish, such as Aeromonas hydrophila, A. salmonicida subsp. masoucida, A. salmonicida subsp. salmonicida, Edwardsiella tarda, Vibrio vulnificus, V. paraheamolyticus using disk diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests. In disc diffusion test, curcumin exhibited concentration-dependent antimicrobial activities to all bacteria pathogens used in the study. Antimicrobial effects of curcumin was found differently depending on bacterial species when determined by MIC or MBC tests. For examples, E. tarda and A. hydrophila was respectively the most sensitive bacterium for bacteriostatic and bacteriocidal effect of curcumin. Collectively, curcumin could be a potential natural drug for controlling pathogenic bacteria in the aquaculture industry.

• 천문학회보
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• 제42권2호
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• pp.37.1-37.1
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• 2017

Since the seminal work of Perrin, physicists have understood in the context of kinetic theory how ink slowly diffuses in a glass of water. The fluctuations of the stochastic forces acting on water molecules drive the diffusion of the ink in the fluid. This is the archetype of a process described by the so-called fluctuation-dissipation theorem, which universally relates the rate of diffusion to the power spectrum of the fluctuating forces. For stars in galaxies, a similar process occurs but with two significant differences, due to the long-range nature of the gravitational interaction: (i) for the diffusion to be effective, stars need to resonate, i.e. present commensurable frequencies, otherwise they only follow the orbit imposed by their mean field; (ii) the amplitudes of the induced fluctuating forces are significantly boosted by collective effects, i.e. by the fact that, because of self-gravity, each star generates a wake in its neighbours. In the expanding universe, an overdense perturbation passing a critical threshold will collapse onto itself and, through violent relaxation and mergers, rapidly converge towards a stationary, phase-mixed and highly symmetric state, with a partially frozen orbital structure. The object is then locked in a quasi-stationary state imposed by its mean gravitational field. Of particular interests are strongly responsive colder systems which, given time and kicks, find the opportunity to significantly reshuffle their orbital structure towards more likely configurations. This presentation aims to explain this long-term reshuffling called gravity-driven secular evolution on cosmic timescales, described by extended kinetic theory. I will illustrate this with radial migration, disc thickening and the stellar cluster in the galactic centre.

• 한국식품영양과학회지
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• 제39권7호
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• pp.1083-1086
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• 2010

본 연구에서는 대두 isoflavone의 하나인 daidzein의 콜레스테롤 당전이 효소에 대한 저해효과와 헬리코박터에 대한 항균력을 측정하였다. 콜레스테롤 당전이 효소는 헬리코박터 파이로리의 세포벽 지질성분을 구성하는 $\alpha$-glucosyl cholesterol을 생성하는 데 관여하는 효소로 헬리코박터의 생육에 있어서 중요한 역할을 하고 있다. Daidzein을 농도별로 처리하였을 경우, 콜레스테롤 당전이 효소의 활성은 daidzein의 농도에 의존적으로 저해를 나타내었으며, daidzein의 $IC_{50}$값은 $128.5\;{\mu}M$이었다. 또한 disc diffusion 방법을 이용하여 항균실험에 있어서도 daidzein은 헬리코박터의 생육을 억제하였다. 이상의 결과를 통하여 daidzein의 효소저해 활성은 헬리코박터의 생육 저해와 밀접한 연관이 있는 것으로 판단된다.

• 분석과학
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• 제30권3호
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• pp.113-121
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• 2017

Now a day's rise of new antibiotic resistant bacterial strains is a global threat. Ethnic people of India have been employing Aphanamixis polystachya (Wall.) R. Parker wood extract in healing cancerous wounds. The aim of this study was to evaluate the antimicrobial activity and to identify the medicinally potent chemicals in the essential oil extract of A. polystachya. The antibacterial properties of various organic extracts were evaluated against a range of bacteria (gram-positive and gram-negative bacteria) based on the disc diffusion method and GC-MS based analysis for finding active oil extract components. All extracts of A. polystachya leaves showed potential antibacterial activity, notably ethyl acetate, while petroleum ether extracts revealed highly sensitive activity against all tested bacteria (zones of inhibition ranging from 8.83 to 11.23 mm). In addition, the petroleum ether extract had the lowest MIC value (32 to $256{\mu}g/mL$) against E. coli, S. lutea, X. campestris, and B. subtilis bacteria. The major compounds detected in oil [${\beta}$-elemene (16.04 %), ${\beta}$-eudesmol (12.78 %), ${\beta}$-caryophyllene (19.37 %), ${\beta}$-selinene (11.32 %), elemol (5.76 %), and ${\alpha}$-humulene (5.68 %)] are expected to be responsible for the potent antimicrobial activity. The results of this study offer valuable insights into the potent role of A. polystachya essential oil extract in pharmaceutical and antibiotic research.

• 한국응용과학기술학회지
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• 제33권2호
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• pp.225-231
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• 2016

본 연구는 잘피 추출물의 화장품 소재로서 활용가능성을 평가하기 위해 건조된 잘피 전체, 뿌리, 잎 줄기를 70% 에탄올로 추출하여 항균활성을 확인하였다. 잘피 추출물의 항균활성은 Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Propionibacterium acnes 균주로 disc diffusion 방법을 통해 생육저해환(clear zone)을 측정하였다. 그 결과 잘피 뿌리 추출물처리군에서 Staphylococcus epidermidis의 clear zone이 $13.00{\pm}0.50mm$로 확인되었고, Staphylococcus aureus, Propionibacterium acnes, Pseudomonas aeruginosa의 clear zone은 각각 $11.75{\pm}0.25mm$, $12.00{\pm}0.50mm$, $12.25{\pm}0.25mm$로 확인되어 잘피 추출물의 항균 효능을 확인할 수 있었다.

• Journal of Periodontal and Implant Science
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• 제26권3호
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• pp.625-639
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• 1996

The purpose of this study was to an in estimate the antibiotic susceptibility of P. gingivalis and P. interrnedia isolate from the subgingival plaque to adult periodontitis. Six P. gingivalis and five P. intermedia bacterial strains were tested for their susceptibility to 10 antimicrobial agents under disc diffusion method and broth dilution method. Ten patients with deep pocket(6mm) were selected for this study. They had not taken antibiotics for 6 months and no history of dental treatment for 6 months before this study. The result were as follow : 1. For antibiotic disc diffusion method, six P. gingivalis and five P. interrnedia were tested with 10 antimicrobial agents which comprised penicillin, gentamycin, clindamycin, lincomycin, ampicillin, erythromycin, tetracycline, amikacin, chloramphenicol, vancomycin. The sensitive antibiotics were tetracycline, penicillin, ampicillin, vancomycin, chloramphenicol and resisitent antibiotics were lincomycin. The other antimicrobial agents were less active. 2. From the study of determination on the minimal inhibitory concentration(MIC) by broth dilution method, the MIC of tetracycline to P. gingivalis and P. intermedia were $0.5-1.0{\mu}g/ml$, $0.5{\mu}g/ml$, that of ampicillin were $1-8{\mu}g/ml$, that of clindamycin were $1-32{\mu]g/ml$, $8-16{\mu}g/ml$, that of lincomycin were $16-32{\mu}g/ml$, $2-32{\mu}g/ml$. These data suggest that tetracycline and ampicillin may be valuable drug in the elemination of P. gingivalis and P. interrnedia from the patients with adult periodontitis.