• International Journal of Oral Biology
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• 제34권3호
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• pp.165-168
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• 2009

Postantibiotic effect (PAE) is defined as the length of time that bacterial growth is suppressed following brief exposure to an antibiotic. In this study, the in vitro PAE, postantibiotic sub-MIC effect (PA SME) and sub-MIC effect (SME) of antibiotics on Treponema denticola ATCC 35405 were investigated. The PAE of doxycycline and metronidazole were 20.3 h and 25.0 h, respectively. The PA SMEs examined by addition of 0.1, 0.2 and 0.3X MICs during the postantibiotic phase of the bacteria for metronidazole were longer than those for doxycycline. In contrast, the SMEs for doxycycline were longer than those for metronidazole. The PA-SME and SME values increased as the concentration of antibiotics increased. The present study illustrates the existence of PAE, PA-SME and SME for several antibiotics against T. denticola, thereby extending the pharmacodynamic advantages of these antibiotics.

• 미생물학회지
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• 제29권6호
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• pp.353-360
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• 1991

5-substituted uridine(I,Br,Cl), 5'-amino-5'-deoxyuridine conjugates of amino acid, peptide and penicillin G, 5'-monophosphate uridine derivatives and 5'-monophosphate-fatty acid detrivatives were chemically synthesized. Their biological activities were determined as MIC and IC/sub 50/ unit against various pathogenic microorganisms in vitro. 5'-amino-5'-deoxyuridine-cyclo(Phe-Asp)(23), 5-iodo-5'-amino-deoxyuridine-penicillin G(26) were the most efficient; their IC/sub 50/ against L5178Y murine lymphoma cell was 6.5 h/ml, MIC against S. aureus (+) and E. coli (-) was 6.25 g/ml. MIC of 5-bromo-2', 3'-O-isopropylideneuridine(6) against Trichophyton rubrum was 0.2 g/ml. And 5'-monophosphate derivatives are more active than simple uridine derivatives, suggesting other modified nucleoside 5'-phosphate may be worthwhile examing further as a new prodrugs.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2252-2254
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• 1998

As the state of the art for handling multimedia on the internet is developed a new system called WebCAM which services video and image came out. However, WebMIC site for audio services are still rare. In this work, we developed a WebMIC system which enables anyone to listen audio in real-time through the internet. WebMIC system is implemented by connecting a server with a microphone and the recorded audio files are stored in a Database system. Because the microphones can be distributed sporadically, the developed system can be utilized for managing and advertizing a location. It also can be used to reduce the cost for the existing management system which is almost met by personnel expenses. Anyone who can connect to the internet can get this WebMIC service, so this system can produce a good effect if used in advertising any tourist resort.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.287.1-287.1
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• 2014

본 연구에서는 현재 디스플레이에서 가장 널리 이용되는 저온 polycrystalline silicon (poly-Si)의 결정화 방법에 따른 thin-film transistor (TFT)의 전기적 특성을 분석하였다. 분석에 이용된 결정화 방식은 Excimer Laser Annealing (ELA)와 Metal Induced Crystallization (MIC)이다. ELA와 MIC TFTs의 전기적 특성 측정을 통한 분석결과 ELA와 MIC poly-Si TFTs의 전기적 특성 [field-effect mobility (${\mu}_{FE}$), on/off current ratio ($I_{ON}/I_{OFF}$), sub-threshold swing (SS)]은 큰 차이는 없지만, ELA를 이용한 poly-Si TFT의 전기적 특성이 조금 우수하다. 하지만, MIC poly-Si TFT의 경우 threshold voltage ($V_{TH}$)가 0V에 보다 가까울 뿐만 아니라, 전기적 스트레스를 통한 신뢰성 확인 시 ELA poly-Si TFT보다 조금 더 안정적이다. 이는 ELA의 경우 좁은 면에 선형 레이저 빔으로 조사하면서 생기는 hill-lock의 영향으로 표면이 거칠고 균일하지 못하여 바이어스 인가시 생기는 문제이다. 또한 MIC는 금속 촉매를 이용해 결정립 경계를 확장하고 결정 크기를 키워 대면적화에 유리하다. Thermal Stress에서는 (from 293K to 373K) TFT에 점차 높은 온도를 가하자 MIC poly-Si TFT의 경우 off 상태에서 누설 전류 값이 증가하며 열에 민감한 반응을 보이는 것을 확인하였다.

• KSBB Journal
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• 제31권4호
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• pp.312-314
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• 2016

This study was carried out to determine the antifungal activity of $SeO_2$ against pathogenic fungus, Candida albicans. Concentration-dependent Inhibitory activity of $SeO_2$ against C. albicans was shown. When $400{\mu}g/disc$ of $SeO_2$ was tested, the inhibition size ranged from 20.7 to 26.8 mm (avg. 23.4 mm). MIC values of $SeO_2$ against cell growth of C. albicans ranged from 50 to $100{\mu}g/mL$ (avg. $70{\mu}g/mL$). These results could be applied to antibiotics-resistant C. albicans and other pathogenic fungi.

• Fisheries and Aquatic Sciences
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• 제25권11호
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• pp.579-586
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• 2022

Research on the potential biological activity of red alga Symphyocladia spp. has been limited to Symphyocladia latiuscula, which is widely used as a food ingredient in Korea. Here, we examined the biological activity of another species, Symphyocladia linearis, which is found in Korea and was reported as a new species in 2013. The aim of this study was to evaluate the antioxidant, anti-inflammatory, and antibacterial properties of a 70% ethanol extract of S. linearis. Antioxidant activity, which was evaluated using radical scavenging assays, revealed half maximal inhibitory concentration values for 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) of 34.57 and 11.70 ㎍/mL algal extract, respectively. Anti-inflammatory activity of the S. linearis ethanolic extract was evaluated using RAW 264.7 cells by measuring the inhibition of lipopolysaccharide-induced nitric oxide (NO) and prostaglandin E₂ (PGE₂) production. The potential cytotoxicity of NO and PGE₂ was first examined, confirming no toxicity at concentrations ranging from 10-100 ㎍/mL. NO production was inhibited 61.1% and 78.0% at 50 and 100 ㎍/mL S. linearis extract, respectively; and PGE₂ production was inhibited 69.1%, 83.2%, and 94.8% at 25, 50, and 100 ㎍/mL S. linearis extract, respectively. Thus, the S. linearis extract showed very strong efficacy against PGE₂ production. The cellular production of reactive oxygen species, measured using 2',7'-dichlorofluorescin diacetate fluorescence, was inhibited 48.8% by the addition of 100 ㎍/mL S. linearis extract. Antibacterial activity was evaluated using the disc diffusion method and minimum inhibitory concentration (MIC). S. linearis was effective only against gram-positive bacteria, exhibiting antibacterial activity against Staphylococcus aureus with a MIC of 256 ㎍/mL extract and against Bacillus cereus with a MIC of 1,024 ㎍/mL extract. Based on these results, we infer that a 70% ethanolic extract of S. linearis possesses strong anti-inflammatory properties, and therefore has the potential to be used in the prevention and treatment of inflammatory and immune diseases.

• Journal of Microbiology and Biotechnology
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• 제24권8호
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• pp.1059-1064
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• 2014

Staphylococcus aureus is a major human pathogen, implicated in both community and hospital acquired infections. The therapy for methicillin-resistant Staphylococcus aureus (MRSA) infections is becoming more difficult because of multidrug resistance and strong biofilm-forming properties. Schiff bases have attracted attention as promising antibacterial agents. In this study, we investigated the in vitro activity of taurine-5-bromosalicylaldehyde Schiff base (TBSSB) against MRSA. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) were determined using a microtiter broth dilution method. TBSSB effectively inhibited planktonic MRSA, with an MIC of $32{\mu}g/ml$. The time-kill curve confirmed that TBSSB exhibited bactericidal activity against MRSA. TBSSB was also found to significantly inhibit MRSA biofilm formation at 24 h, especially at $1{\times}MIC$ and sub-MIC levels. Furthermore, scanning electron microscopy and transmission electron microscopy showed remarkable morphological and ultrastructural changes on the MRSA cell surface, due to exposure to TBSSB. This study indicated that TBSSB may be an effective bactericidal agent against MRSA.

• Journal of Plant Biotechnology
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• 제49권4호
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• pp.339-346
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• 2022

본 연구는 벌나무 에탄올 추출물의 황색포도상구균에 대한 항균 및 항산화 활성을 검증하였다. 총 폴리페놀 및 플라보노이드 함량, DPPH와 ABTS 라디칼 소거효능과 FRAP법을 사용한 환원력을 측정하여 벌나무 에탄올 추출물의 항산화활성을 검증하였고, Paper disc법, MIC 및 MBC법을 통하여 황색포도상구균에 대한 벌나무 에탄올 추출물의 항균 활성을 검증하였다. 총 폴리페놀 및 플라보노이드 함량은 각각 266.66 ㎍ GAE/mg와 6.46 ㎍ QE/mg이었다. DPPH와 ABTS 라디칼 소거능은 농도 의존적 소거능을 보였고, 벌나무 에탄올 추출물의 RC₅₀ 값은 각각 21.49, 12.81 ㎍/mL이었다. 환원력을 평가하기 위해 수행된 FRAP 분석에서 벌나무 추출물은 0.73 ± 0.19 mM FeSO₄ E/mg의 효능을 보여주었다. Paper disc법을 이용한 황색포도상구균에 대한 벌나무 추출물의 항균 활성은 2 mg에서 3 mm의 저해환을 보여주었으며, 최소 저해농도 연구에서는 1 mg/mL 이상의 농도에서 80% 이상의 억제력을 보여주었고, 16 mg/mL 이상의 농도에서 최소저해 농도를 확인할 수 있었다. 또한, 최소살균농도 연구에서는 32 mg/mL에서 최소살균농도를 확인할 수 있었다. 벌나무 추출물을 사용한 항산화 및 황색포도상구균에 대한 항균 활성을 확인한 결과 벌나무 추출물의 아토피피부염에 유효한 물질로서의 가능성을 확인할 수 있었다.

• International Journal of Oral Biology
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• 제42권3호
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• pp.123-128
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• 2017

Recurrent aphthous stomatitis (RAS) is a common oral mucosal disorder for which no curative treatment is available. We previously reported that decreased Streptococcus salivarius and increased Acinetobacter johnsonii on the oral mucosa are associated with RAS risk. The purpose of this study was to identify antibiotics that selectively inhibit A. johnsonii but minimally inhibit oral mucosal commensals. S. salivarius KCTC 5512, S. salivarius KCTC 3960, A. johnsonii KCTC 12405, Rothia mucilaginosa KCTC 19862, and Veillonella dispar KCOM 1864 were subjected to antibiotic susceptibility test using amoxicillin, cefotaxime, gentamicin, clindamycin, and metronidazole in liquid culture. The minimal inhibitory concentration (MIC) was defined as the concentration that inhibits 90% of growth. Only gentamicin presented a higher MIC for A. johnsonii than MICs for S. salivarius and several oral mucosal commensals. Interestingly, the growth of S. salivarius increased 10~200% in the presence of sub-MIC concentrations of gentamicin, which was independent of development of resistance to gentamicin. In conclusion, gentamicin may be useful to restore RAS-associated imbalance in oral microbiota by selectively inhibiting the growth of A. johnsonii but enhancing the growth of S. salivarius.

• 대한화장품학회지
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• 제24권3호
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• pp.89-95
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• 1998

The aim of this study is to elucidate the anti-microbial activity and anti-oxidative activity of water-soluble chitosan with a molecular weight of 5,000-200,000. Water-soluble chitosans have demonstrated a regular anti-microbial activity on the tested strians by the paper disk method. In the MIC (Minimum Inhibitory Concentration) test, CC-01 (MW=5,000) with the lower MW showed the higher MIC value than the higher MW chitosan. The MW of chitosan increase, the MIC decreases. MICs of 4 chitosans(CC-02∼CC-05) against S. aureusTCC 65389, E coli ATCC 8739, p. aeruginosa, ATCC 9027 and C. albicans ,ATCC 10231 were 7.0-39.O$\mu\textrm{m}$, whereas MICs of chitosans against A. niger were over 2.OmM. Formula containing chitosan showed higher anti-microbial activities than the formula made with the chemical preservatives(Methylparaben 0.2％ and Imidazolidinyl Urea 0.3％). Among 5 water-soluble chitosans, CC-03(MW=92,163) showed the most potent anti-oxidative activity (IC$\sub$50/ : 0.2mM). In conclusion, the water-soluble low molecular weight chitosan could be served as natural preservatives and antioxidant in cosmetics.