• Journal of Microbiology and Biotechnology
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• v.16 no.6
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• pp.880-888
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• 2006

Pleurocidin, an $\alpha$-helical cationic antimicrobial peptide, was isolated from skin mucosa of winter flounder (Pleuronectes americamus). It had strong antimicrobial activities against Gram-positive and Gram-negative bacteria, but had very weak hemolytic activity. The Gly$^{13,17}\rightarrow$Ala analog (pleurocidin-AA) showed similar antibacterial activities, but had dramatically increased hemolytic activity. The bacterial cell selectivity of pleurocidin was confirmed through the membrane-disrupting and membrane-binding affinities using dye leakage, tryptophan fluorescence blue shift, and tryptophan quenching experiments. However, the non-cell-selective antimicrobial peptide, pleurocidin-AA, interacts strongly with both negatively charged and zwitterionic phospholipid membranes, the latter of which are the major constituents of the outer leaflet of erythrocytes. Circular dihroism spectra showed that pleurocidin-AA has much higher contents of $\alpha$-helical conformation than pleurocidin. The tertiary structure determined by NMR spectroscopy showed that pleurocidin has a flexible. structure between the long helix from $Gly^3$ to $Gly^{17}$ and the short helix from $Gly^{17}$ to $Leu^{25}$. Cell-selective antimicrobial peptide pleurocidin interacts strongly with negatively charged phospholipid membranes, which mimic bacterial membranes. Structural flexibility between the two helices may play a key role in bacterial cell selectivity of pleurocidin.

• Journal of Information Display
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• v.9 no.4
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• pp.21-29
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• 2008

We studied both the wavelength and intensity dependent photo-responses (photofield-effect) in amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs). During the a-IGZO TFT illumination with the wavelength range from $460\sim660$ nm (visible range), the off-state drain current $(I_{DS_off})$ only slightly increased while a large increase was observed for the wavelength below 400 nm. The observed results are consistent with the optical gap of $\sim$3.05eV extracted from the absorption measurement. The a-IGZO TFT properties under monochromatic illumination ($\lambda$=420nm) with different intensity was also investigated and $I_{DS_off}$ was found to increase with the light intensity. Throughout the study, the field-effect mobility $(\mu_{eff})$ is almost unchanged. But due to photo-generated charge trapping, a negative threshold voltage $(V_{th})$ shift is observed. The mathematical analysis of the photofield-effect suggests that a highly efficient UV photocurrent conversion process in TFT off-region takes place. Finally, a-IGZO mid-gap density-of-states (DOS) was extracted and is more than an order of magnitude lower than reported value for hydrogenated amorphous silicon (a-Si:H), which can explain a good switching properties observed for a-IGZO TFTs.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.214-222
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• 2008

The equivalent circuit for the RLH-TL is proposed considering radiation effects due to the inclusion of a series capacitor and shunt inductor in a unit cell for the right/left-handed transmission line(RLH-TL). The design equations to realize a specific phase shift at a given frequency is also provided. The S-parameters for unit cells with N=1, 3, 5, and 10 are analyzed in various aspects based on the EM and circuit simulations especially for the purpose of controlling radiation along RLH-TL's. A modification formula for the radiation rate per unit cell is also proposed for good agreement between the EM and circuit simulation results.

• The Korean Journal of Emergency Medical Services
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• v.10 no.3
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• pp.71-85
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• 2006

Purpose: The purpose of this study is to investigate the relationship among the variables, personality type, stress, and job satisfaction in firefighters. Methods: The questionnaire research was conducted for field service firefighters who work in two cities for the period of June 20, 2005 through July 20, 2005. A total number of 308 data were used for this analysis. For analysis of the data, the SPSSWIN 10.0 program was used to analyze descriptive statistics, correlation analysis, t-test and one-way ANOVA. Results: The mean score of subjects' stress was 3.30 and the mean score of job satisfaction was 2.86. There were significant differences on stress and job satisfaction by general characteristics. Stress was significantly differed by field of working. Job satisfaction was significantly differed by marital status and field of working. Also, there were significant differences on stress and job satisfaction by characteristics related to working. Stress was significantly differed by sleeping time at night shift, witness their superior's or companion's death or injury, and a threat to death or injury. Job satisfaction was significantly differed by an aptitude for field of working and wish to change the field of working. But there was no significant differences on stress and job satisfaction by personality type. There was statistically significant negative correlation between stress and job satisfaction. Conclusion: Strategies that can decrease their stress need to be developed to increase job satisfaction.

• The Journal of Information Systems
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• v.23 no.4
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• pp.49-74
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• 2014

The introduction of smartphone caused the most revolutionary change in the domestic telecommunications market after the digital revolution. However, due to the saturation of the local market, it is expected to post negative growth in 2016 and the sales of national communication carriers is in stasis. Thus, the smartphone industry is starting to shift its marketing efforts to secure the silver generation who still has room for increase in the rate of smartphone usage. As the silver generation has physical limitations and differences in needs, the marketing strategy based on the smartphone utilization is not appropriate. This study suggests the new silver generation, who has high income level and similar characteristics to the younger generation, as the new customer segment for smartphone. We analyze the effects of the major variables of UTAUT on smartphone use, as well as examine how these relationships differ between the new silver and the net generation. We verified the hypotheses using a survey with 309 smartphone users. The research findings supported the hypotheses regarding the effects of performance expectancy, effort expectancy and facilitating conditions on smartphone use, but did not support the hypothesis on the effect of social influence. The result of the group comparisons showed that both generation have similar characteristics on innovativeness and cognitive absorption, but the moderating effect of age on performance expectancy, effort expectancy and use is stronger in conjunction with the new silver generation. The study results are expected to be used in establishing a marketing strategy for the new silver generation.

• Journal of Powder Materials
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• v.17 no.4
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• pp.289-294
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• 2010

For the aim of low-temperature co-fired ceramic microwave components, sintering behavior and microwave properties (dielectric constant ${\varepsilon}_r$, quality factor Q, and temperature coefficient of resonant frequency ${\tau}_f$) are investigated in $Bi_{18}O(Ca_{0.725}Zn_{0.275})_8Nb_{12}O_{65}$ [BCZN] ceramics with addition of $V_2O_5$. The specimens are prepared by conventional ceramic processing technique. As the main result, it is demonstrated that the additives ($V_2O_5$) show the effect of lowering of sintering temperature and improvement of microwave properties at the optimum additive content. The addition of 0.25 wt% $V_2O_5$ lowers the sintering temperature to $890^{\circ}C$ utilizing liquidphase sintering and show the microwave dielectric properties (dielectric constant ${\varepsilon}_r$ = 75, quality factor $Q{\times}f$ = 572 GHz, temperature coefficient of resonance frequency ${\tau}_f\;=\;-10\;ppm/^{\circ}C$). The estimated microwave dielectric properties with $V_2O_5$ addition (increase of ${\varepsilon}_r$, decrease of $Q{\times}f$, shift of ${\tau}_f$ to negative values) can be explained by the observed microstrucure (sintered density, abnormal grain structure) and possibly high-permittivity $Bi_{18}Zn_8Nb_{12}O_{65}$ (BZN) phase determined by X-ray diffraction.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.4
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• pp.339-341
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• 2007

A 22-year-old woman with a history of acute lymphoblastic leukemia was hospitalized for headache and vomiting. CT scan showed a well-defined, ring like enhancing mass in the left frontal lobe with surrounding edema and midline shift. Magnetic resonance imaging demonstrated a round homogeneous mass with a ring of enhancement in the left frontal lobe. Tl-201 brain SPECT showed increased focal uptake coinciding with the CT and MRI abnormality. Aspiration of the lesion performed through a burr hole yielded many neutrophils, a few lymphocytes and histiocytes with some strands of filamentous microorganism-like material. Modified AFB stained negative for norcardia. Gram stain showed a few white blood cells and no microorganism. Antibiotics were started and produced a good clinical response. After one month, CT scan showed markedly reduction in size and extent was observed.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.529-539
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• 1998

The effects of membrane surface charge originated from lipid head groups on ion channels were tested by analyzing the activity of single large conductance $Ca^{2+}-activated\;K^+$ (maxi K) channel from rat skeletal muscle. The conductances and open-state probability ($P_o$) of single maxi K channels were compared in three types of planar lipid bilayers formed from a neutral phosphatidylethanolamine (PE) or two negatively-charged phospholipids, phosphatidylserine (PS) and phosphatidylinositol (PI). Under symmetrical KCl concentrations $(3{\sim}1,000\;mM)$, single channel conductances of maxi K channels in charged membranes were $1.1{\sim}1.7$ times larger than those in PE membranes, and the differences were more pronounced at the lower ionic strength. The average slope conductances at 100 mM KCl were $251{\pm}9.9$, $360{\pm}8.7$ and $356{\pm}12.4$ $(mean{\pm}SEM)$ pS in PE, PS and PI membranes respectively. The potentials at which $P_o$ was 1/2, appeared to have shifted left by 40 mV along voltage axis in the membranes formed with PS or PI. Such shift was consistently seen at pCa 5, 4.5, 4 and 3.5. Estimation of the effect of surface charge from these data indicated that maxi K channels sensed the surface potentials at a distance of $8{\sim}9\;{\AA}$ from the membrane surface. In addition, similar insulation distance ($7{\sim}9\;{\AA}$) of channel mouth from the bilayer surface charge was predicted by a 3-barrier-2-site model of energy profile for the permeation of $K^+$ ions. In conclusion, despite the differences in structure and fluidity of phospholipids in bilayers, the activities of maxi K channels in two charged membranes composed of PS or PI were strikingly similar and larger than those in bilayers of PE. These results suggest that the enhancement of conductance and $P_o$ of maxi channels is mostly due to negative charges in the phospholipid head groups.

• Fire Science and Engineering
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• v.34 no.4
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• pp.125-134
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• 2020

This paper aimed to statistically analyze the impact of fire needs not considered in previous reports based on preventive and preparedness strategies of fire administration and fire budget.. The panel data came from 16 metropolitan councils from 2008 to 2018 and was statistically analyzed based on the preventive measures of the fire administration (agreement for building permission, specific target for fire-fighting, public use facilities, and special fire inspection [SFI]), preparedness of the fire administration (fire safety education [FSE]), response of the fire administration (mobilization for fire suppression [MFS] and mobilization for ambulance service [MAS]), and fire budget. In the results, SFI, FSE, and MFS had a significant negative influence on the fire budget. Meanwhile, MAS had a significant positive effect on the fire budget (p < 0.01). These results reflect public policy in Korea; there has been a paradigm shift in fire administration: from disaster acceptance (focusing on recovery) to disaster response (focusing on field response) to disaster preparedness (focusing on preparedness).

• Environmental and Resource Economics Review
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• v.19 no.2
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• pp.243-282
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• 2010

In this paper, we analyze the components and trends of carbon emissions using the Logarithmic Mean Divisia Index decomposition method in Korean electricity industry during the period 1991~2007. In the demand side, carbon emissions are affected by electricity intensity and structural shift and especially electricity intensity is identified as the major factor which has lead carbon emissions decreasing. In the supply side, the result in variations of carbon emission for electric power generation depends on the influences of fossil fuel mix, fuel intensity, generation mix and so on. As a result fuel intensity is the most negative effect on both carbon emission intensity and the amount of carbon emission while the change of generation mix has a positive effect on increasing carbon emissions. And to conclude it needs to make the strategic policies to improve electricity intensity in the demand and to rise emission efficiency as well as to substitute thermal power generation in supply side.