• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.245-248
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• 1997

The dielectric resonators(DRs) with dielectric properties are widely used in microwave integrated circuit(MICs) and monolithic microwave integrated circuits(MMICS). The variational method as numerical simulation scheme would be applied to calculate the resonant frequencies(fr) and Q-factors of microwave dielectric resonators. The dielectric resonator with a cylindrical “puck” structure of high dielectric material is modeled in this simulation. The parameters, such as the diameter, the height, and the dielectric constant of dielectric resonator, would determine the resonant frequency and the Q-factor. The relationship between these parameters would effect each other to evaluate the approximate resonant frequency. This simulation method by the variational formula is very effective to calculate fr, and Q-factor. in high frequency microwave dielectric resonator The error rate of the simulation results and the measured results would be considered to design the microwave dielectric resonators.

• Archives of Pharmacal Research
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• v.27 no.9
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• pp.885-892
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• 2004

Due to the rapidly growing number of resistant strains of bacteria, the search for antibacterial agents with new modes of action will always remain an important and challenging task. Thus, the reaction of 2-substituted or. unsubstituted-4-(4-acetylanilino)-5,6,7,8-terahydrobenzo［b］ thieno［2,3-d］pyrimidine derivatives 1-3 with the hydrazine derivatives, semi and / or thiosemi-carbazides, provided the corresponding hydrazones 4-6 and semi and/or thiosemicarbazones 7-9. Claisen-Schmidt condensation of compounds 1 or 2 with the appropriate aldehyde yielded the chalcones 10, 11 which, when treated with hydroxylamine hydrochloride gave rise to the isoxazoline-containing compounds 12, 13. Furthermore, reacting the respective chalcones 10, 11 with different hydrazines, urea and/or thiourea, furnished compounds 14, 15, 16, and 17 respectively. Representative compounds were tested for their antimicrobial activity against Candida Albicans and certain gram-positive and gram-negative bacteria. Their MICs were then determined. Compound 15e, showed a broad spectrum of activity while most of the other com-pounds showed varying antimicrobial activity.

• Korean Journal of Microbiology
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• v.19 no.3
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• pp.103-107
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• 1981

Increasing the concentration of the nonionic surfactants the solubility of methyl paraben was increased. This is called the solubilization phenomenon and caused inactivation of the preservatives used. The MICs(minimum inhibitory concentrations) on E. coli were increased at the same time. So the relation between the solubility and the mic could be expressed as $S-S_0=R^{\prime}/R^{\prime\prime}\;(M-M_0)$ and in this case $R^{\prime}/R^{\prime\prime}$ was about 2.

• Archives of Pharmacal Research
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• v.15 no.1
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• pp.99-103
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• 1992

Susceptibility of Psudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis to gentimicin and ceforaxime was affected by salicylaye. In presence of salicylaye (15 mM) and gentamicin (1.0 .mu.g/ml), log efficiency of plating (log E. O. P. s) for the tested bacteria were -1.24, -2.17 and -1.66 respectively. The activity of cefotaxime against Bacillus subtilis was reduced (log E. O. P. = 1.33). The highest potentiating effects of salicylaye were shown when using gentamicin against Staphylococcus aureus, cefotaxime against Ps. aeruginosa, log E. O. P.s were -3.0, and -2.4 respectively. On the other hand, no significant effects were detected with cefotaxime against Staphylococcus aureus (log E. O. P. = -0.04). No significant killing was shown in presence of gentamicin or salicylaye alone. There was no significant effect for salicylaye on MICs (By broth dilution) could be observed except in case of gentamicin against Staphyloccus aureus, which was reduced from 0.02 .mu.g/ml to 0.0012 .mu.g/ml. These results raise the concern that high concentrations of salicylaye in patients might interfere with antibiotic therapies.

• Natural Product Sciences
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• v.13 no.1
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• pp.85-89
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• 2007

To determine whether the essential oil from Coriandum sativum and its main component, linalool, exhibit antifungal activity, we employed a broth dilution assay and disk diffusion test using common pathogenic Candida and Trichophyton species. Both coriander oil and linalool significantly inhibited growth of the tested fungi, with minimal inhibitory concentrations (MICs) in the range of $0.03{\sim}2mg/ml$. Furthermore, in a checkerboard titer test, both the oil fraction and linalool exhibited synergism when combined with ketoconazole, with resultant FICIs ranging from 0.06 to 0.53. Notably, hyphal formation in C. albicans cells was obviously inhibited by C. sativum essential oil in this experiment.

• International Journal of Oral Biology
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• v.34 no.3
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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.

• 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.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.170-173
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• 2010

최근 진보된 무선 통신 기술과 발전된 의료 기술로 인하여 u-Health의 핵심 기술인 WBAN에 대한 연구가 활발히 진행되고 있다. 인체에 이식 가능한 WBAN 장치는 전원 공급에 제한이 있으므로 소비전력을 최소화하기 위한 MAC 프로토콜이 필요하다. 본 논문은 WBAN 장치의 다양한 무선 통신 특성을 적용한 시뮬레이터에 관한 것으로 MICS 대역의 채널 특성을 적용하였고, 데이터의 신뢰성과 에너지 효율성을 향상시키기 위해 가변 패킷 및 비트맵 기반의 패킷 블록 전송기법을 적용한 MAC 프로토콜을 사용한다.

• Korean Journal of Pharmacognosy
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• v.28 no.3
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• pp.99-103
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• 1997

To develop anticariogenic agents, Scutellariae Radix was tested for its antibacterial activity against Streptococcus mutans OMZ176 which is known as a strong cariogenic bacterium. The antibacterial activity was evaluated with disk plate method and minimal inhibitory concentration (MIC). The ethyl acetate fraction showed significant activity. By means of activity-guided fractionation, baicalein and ganhuangenin were isolated as the active principles. The MICs of these compounds were $100{\mu}g/ml$ and $200{\mu}g/ml$, respectively.

• Natural Product Sciences
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• v.16 no.3
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• pp.175-179
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• 2010

The present study aimed to assess the antifungal properties of the essential oil fraction from Ligusticum chuanxiong (Umbelliferae) and its components against five clinically important Aspergillus species. The essential oil fraction was extracted from the underground parts of the plant by steam distillation, and its main components, namely, Z-ligustilide, butylidene phthalide, and p-cresol were isolated by column chromatography. The antifungal activities of the essential oils were evaluated by the broth dilution method. Both the total essential oil fraction of L. chuanxiong and its components showed significant anti-Aspergillus activity against all five tested strains with MICs between 62.5 and 250 ${\mu}g$/ml, respectively. In a checkerboard microtiter assay, the combination of antibiotics, itraconazole with the essential oil fraction of L. chuanxiong or its main components exhibited synergistic or additive, and in some cases indifferent, effects against the tested Aspergillus species, resulting in FICIs (fractional inhibiting concentration indices) ranging from 0.12 to 2, while the combination of antibiotics, amphothericin B with L. chuanxiong essential oils mostly showed antagonistic effects.