• Journal of Microbiology
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• v.33 no.3
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• pp.215-221
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• 1995

S. coelicolor A3(2) cells were treated with various redox-cycling agents on nutrient agar plates and examined for their effect on the growth and differentiation. When treated with plumbagin, severe effect on cell viability was observed at concentrations above 250 $\mu$M. However, the surviving colonies differentiated normally. When treated with 100 $\mu$M paraquat, growth rate was decreased and morphological differentiation was inhibited, while the survival rate was maintained at about 100% even at 5 mM paraquat. Menadione or lawsone did not cause any visible changes at concentrations up to 1 mM. The effect of paraquat was also observed when it was added to nutrient agar plate before spore inoculation. Paraquat had also observed when it was added to nutrient agar plate before spore inoculation. Paraquat had no effect on colonies growing on R2YE agar plates. Among the components of R2YE medium selectively added to nutrient agar medium, CaCl$_2$ was found to have some protective function from the inhibitory effect of paraquat. As a first step to study the mechanism of the inhibitory effect of paraquat on differentiation, resistant mutants which sporulate well in the presence of paraquat were screened following UV mutagenesis. Three paraquat-resistant mutants were isolated with a frequency of 3 $\times$10${-5}$. Their mutation sites were determined by genetic crossings. All three mutations were mapped to a single locus near arg4 at about 1 o'clock on the genetic map of S. coelicolor A3(2).

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.1
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• pp.70-75
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• 2007

In the present study, we has been isolated the anti-cariogenic component, stigmasterol, from Aralia continentalis (A. continentalis) and identified by MS, $^1$H-NMR and $^{13}$C-NMR and also investigated the anti-cariogenic properties of stigmasterol. The methanol extract of ,A. continentalis showed concentration-dependent inhibitory activity against the growth and acid production of S. mutans. The MeOH extract was suspended in H$_2$O and sequentially partitioned with n-hexane, CHCl$_3$, EtOAc, and n-BuOH. The CHCl$_3$ fraction showed remarkable antibacterial activity against S. mutans. The anti-cariogenic compound, stigmasterol, has been isolated successively through the screening system and various chromatography methods. Anti-cariogenic properties of stigmasterol were also investigated. From this active chloroform subfraction, isolation and identification finally gave (24E)-stigmasta-5,22-dien-3${\beta}$-ol (stigmasterol) {[a]$_D\;^{25}$ -48.33$^{\circ}C$(C 0.28, CHCl$_3$)} by spectroscopic methods (MS, $^1$H-NMR and $^{13}$C-NMR) as an active principle. The compound, stigmasterol, showed significant growth, acid production, adhesion and water-insoluble glucan synthesis inhibitory effect against S. mutans. These results suggest that stigmasterol from ,A. continentalis may inhibit cariogenic properties of S. mutans and these properties may provide some scientific rationales that the local inhabitants used the extracts for treatment of dental diseases.

• Journal of Life Science
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• v.22 no.4
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• pp.472-477
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• 2012

A thermophilic $Alicyclobacillus$ $acidocaldarius$, which produces thermostable ${\alpha}$-amylase, was isolated from the hot water effluent of a boiled rice mill near Tirupati, Andhra Pradesh, India. The effect of different culture conditions on the growth and production of extracellular ${\alpha}$-amylase by thermophilic $A.$ $acidocaldarius$ was investigated in laboratory scale. The results showed that the optimum conditions for the production of ${\alpha}$-amylase are a temperature of $60^{\circ}C$, pH of 6.0, and medium starch concentration of 1.0%, and yeast extract and tryptone of 0.2%. Surfactants, like Tween-20 and SDS, up to 0.02%, were found to increase the bacterial growth and enzymes. Further increase in their concentration resulted in significantly decreased enzyme production.

• Journal of Korean Biological Nursing Science
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• v.11 no.2
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• pp.114-119
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• 2009

Purpose: The effectiveness of an infection control program is important to hospital quality improvement and decreases of mortality rate and prevalence. Methicillin resistant Staphylococcus aureus (MRSA) is the most common pathogen causing nosocomial infection. The aim of the study was to identify the most important risk factors for acquiring an MRSA, to evaluate the MRSA incidence rates after the nursing intervention in Neurosurgery intensive care unit (ICU). Methods: Clinical data were collected prospectively from December 2008 until July 2009 in Neurosurgery ICU. The patients were divided into preintervention and postintervention groups. An infection was defined as an MRSA if it occurred 48 hr after admission to the Unit. Infection control program including hand washing, education of health care workers about MRSA, standard precaution and contact isolation of patients were applied for three month. Results: A total of 85 patients were included in the study. Forty-five patients of S. aurerus were detected. Among 45 of S. aurerus, MRSA were isolated from 38 patients. The incidence MRSA rate of postintervention group was 26.9% while incidence MRSA rate of preintervention group was 66.7%. In total, The incidence MRSA rate was 44.7%. The incidence of MRSA have decreased in the postintervention as compared with the preintervention group. Conclusion: The infection control program for MRSA was effective to decrease the MRSA isolation rate. The health care workers regular hand washing, education of nosocomial infection control is important enough to be emphasized.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.2
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• pp.127-134
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• 2015

In this paper, we propose 2.6 GHz single band dual polarization MIMO omni antenna for in-building applications. The proposed antenna operates at 2.6 GHz single LTE band, Up-link 2.52~2.54 GHz and Down-link 2.64~2.66 GHz. Horizontal and vertical polarizations of the antenna has been, respectively, constructed by the synthesis of four folded loop antennas and the folded monopole antenna. The height of the MIMO omni-directional antenna is minimized to be less than ${\lambda}/13.5$ from the ground. The measurement results show excellent MIMO omni antenna performance of 2.85 dBi vertical polarization gain, 2.29 dBi horizontal polarization gain, and 19.25 dB port isolation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.11
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• pp.1243-1253
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• 2007

Recently UHF RFID system has drawn a great deal of attention because of its potential to revolutionize supply chain management. An important characterization of the performance of a RFID system is 'interrogation range', which is defined as the maximum distance between a reader and a tag. Forward-link interrogation range is defined as the maximum distance from which the tag receives just enough power to turn on and back-scatter, and reverse-tink interrogation range is the maximum distance from which the reader can detect this back-scattered signal. A link balance has to be found between the two interrogation ranges. In this paper, the interrogation range equations are formulated in both forward-link and reverse-link and a trade-off between the two values is investigated in order to maximize the interrogation range. As a result, it is observed that the gain of the reader antenna, the isolation of the circulator, and the phase noise of the local oscillator with range correlation effect mainly determine the reverse-link interrogation range.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.9
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• pp.882-889
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• 2010

Semi-active vibration control is one of the attractive control methods for space application due to its robustness as passive damping system and much higher damping performance than passive system. However, a chattering induced by the sudden variation of damping force at the time of On-Off switching of semi-active control device degrades pointing performance of the on-board payload. In this paper, to enhance the pointing performance of the on-board payload, we proposed a semi-active vibration isolation with a strategy for attenuating chattering effect. Numerical simulation results using simplified analysis model indicated that the proposed semi-active control strategy produced much better isolation performance than the conventional Bang-Bang control semi-active control laws derived from skyhook and LQ theories.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.5
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• pp.363-369
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• 2005

Purpose: To determine the role of Insulin-like Growth Factor-I (IGF-I) in the regulation of Vascular Endothelial Growth Factor (VEGF) expression in MG-63 cells and then to find the mechanism b which this regulation occurs. Materials and methods: MG-63 cells were grown to confluence in 60-mm dishes. To determine the effects of IGF-I on expression of VEGF mRNA according to time and concentration, the cells were treated with 10 nM IGF-I, following isolation of total RNA and Northern blot analysis after 1, 2, 4, 8, 12, 24 hours and after 2 hours of treatment with 0.5, 2, 10, 25, 50 nM IGF-I respectively, isolation of total RNA and Northern blot analysis were followed. To determine the mechanism of action of IGF-I, inhibitors such as hydroxyurea $(76.1\;{\mu}g/ml)$, actinomycin D $(2.5\;{\mu}g/ml)$, cycloheximide $(10\;{\mu}g/ml)$ were added 1 hour after treatment of 10 nM IGF-I. Results: 1. the expression of VEGF mRNA was increased with treatment of IGF-I. 2. The expression of VEGF mRNA was increased according to time-and concentration dependent manner of IGF-I. 3. The effect of IGF-I was decreased by hydroxyuera, actinomycin D, but not by cycloheximide. Conclusion: IGF-I regulate the expression of VEGF mRNA in the level of DNA synthesis and transcription. These results could suggest that IGF-I plays an important role in angiogenesis in the process of new bone formation and remodeling.

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.139-146
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• 2004

A bacterium producing alkaline cellulase was isolated from soil, leaf mold and compost, and was identified as alkalophilic Bacillus sp. HSH-810 by morphological, cultural and biochemical determination. The optimum cul-ture condition of Bacillus sp. HSH-810 for the growth and alkaline cellulase production was $30^{\circ}C$ and pH 10.0. The maximum alkaline cellulase production was obtained when 1.0%(w/v) CMC, 0.5%(w/v) peptone, 0.02%(w/v) $CaCl_2$ and 0.02(w/v) $CoCl_2$ were used as carbon source, nitrogen source and mineral source, respectively. The optimum pH and temperature of the enzyme activity were pH 10.5 and $50^{\circ}C$, respectively. This enzyme was fairly stable in the pH range of 6.0-13.0 and at $50^{\circ}C$. For the effect of surfactants, the activity of alkaline cellulase was stable in the presence of sodium-$\alpha$-olefin sulfonate (AOS), sodium dodecyl sulfonate (SDS), Tween 20 and Tween 80, but inhibited by the presence of 0.1 linear alkyl-benzene sulfonate (LAS) sig-nificantly.

• Journal of the Korean Vacuum Society
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• v.6 no.4
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• pp.343-347
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• 1997

The dependence of compensation mechanism in $P^+$-InGaAs layer implanted with oxygen on the annealing temperatures was investigated. The oxygen implantation was performed for electrical isolation. The conductivity was controlled by damage related traps below $500^{\circ}C$. For the temperature of 500 to $600^{\circ}C$, oxygen began to show the chemical effect of compensating the acceptors due to activation and type conversion (plongrightarrown-type) occurred at $600^{\circ}C$. This indicates that the defects generated by the chemical activity of oxygen increased with increasing annealing temperature, where activation energy of 24.2 meV was obtained. It is attributed to the formation of native defects, such as In interstitials, acting as shallow donor in InGaAs. Above $600^{\circ}C$, the interstitial Be atoms become reactivated and the n-type conductivity decreases.