• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.6
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• pp.529-535
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• 2015

Biological networks have been handled with the static concept. However, life phenomena in cells occur depending on the cellular state and the external environment, and only a few proteins and their interactions are selectively activated. Therefore, we should adopt the dynamic network concept that the structure of a biological network varies along the flow of time. This concept is effective to analyze the progressive transition of the disease. In this paper, we applied the proposed method to Alzheimer's disease to analyze the structural and functional characteristics of the disease network. Using gene expression data and protein-protein interaction data, we constructed the sub-networks in accordance with the progress of disease (normal, early, middle and late). Based on this, we analyzed structural properties of the network. Furthermore, we found module structures in the network to analyze the functional properties of the sub-networks using the gene ontology analysis (GO). As a result, it was shown that the functional characteristics of the dynamics network is well compatible with the stage of the disease which shows that it can be used to describe important biological events of the disease. Via the proposed approach, it is possible to observe the molecular network change involved in the disease progression which is not generally investigated, and to understand the pathogenesis and progression mechanism of the disease at a molecular level.

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.439-445
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• 2004

Diffusion tensor image(DTI) exploits the random diffusional motion of water molecules. This method is useful for the characterization of the architecture of tissues. In some tissues, such as muscle or cerebral white matter, cellular arrangement shows a strongly preferred direction of water diffusion, i.e., the diffusion is anisotropic. The degree of anisotropy is often represented using diffusion anisotropy indices (relative anisotropy(RA), fractional anisotropy(FA), volume ratio(VR)). In this study, FA images were obtained using different gradient schemes(N=6, 11, 23, 35. 47). Mean values and the standard deviations of FA were then measured at several anatomic locations for each scheme. The results showed that both mean values and the standard deviations of FA were decreased as the number of gradient directions were increased. Also, the standard error of ADC measurement decreased as the number of diffusion gradient directions increased. In conclusion, different gradient schemes showed a significantly different noise performance and the schem with more gradient directions clearly improved the quality of the FA images. But considering acquisition time of image and standard deviation of FA, 23 gradient directions is clinically optimal.

• Journal of the Korean Society of Safety
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• v.20 no.4 s.72
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• pp.171-179
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• 2005

It is essential to understand the role of wall lining materials when they are exposed to a fire from an ignition source. Full-scale test methods permit an assessment of the performance of a wall lining material. Fire growth models have been developed due to the costly expense associated with full-scale testing. The models require heat flux maps from the ignition burner flame as input data. Work to date was impeded by a lack of detailed spatial characterization of the heat flux maps due to the use of limited instrumentation. To increase the power of fire modeling, accurate and detailed heat flux maps from the ignition burner are essential. High level spatial resolution for surface temperature can be provided from an infrared camera. The objective of this study was to develop a heat flux mapping procedure for a room test burner flame to a wall configuration with surface temperature information taken from an infrared camera. A prototype experiment was performed using the ISO 9705 test burner to demonstrate the developed heat flux mapping procedure. The results of the experiment allow the heat flux and spatial resolutions of the method to be determined and compared to the methods currently available.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.5
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• pp.285-295
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• 1999

Electroluminescent(EL) devices based on organic materials have been of great interest due to their possible applications for large-area flat-panel displays. They are attractive because of their capability of multi-color emission, and low operation voltage. An approach to realize such device characteristics is to use active layers of lanthanide complexes with their inherent extremely sharp emission bands in stead of commonly known organic dyes. In general, organic molecular compounds show emission due to their $\pi$-$\pi*$ transitions resulting in luminescence bandwidths of about 80 to 100nm. Spin statistic estimations lead to an internal quantum efficiency of dye-based EL devices limited to 25%. On the contrary, the fluorescence of lanthanide complexes is based on an intramolecular energy transfer from the triplet of the organic ligand to the 4f energy states of the ion. Therefore, theoretical internal quantum efficiency is principally not limited. In this study, Powders of TPD, $Eu(TTA)_3(phen) and AlQ_3$ in a boat were subsequently heated to their sublimation temperatures to obtain the growth rates of 0.2~0.3nm/s. Organic electrolumnescent devices(OELD) with a structure of $glass substrate/ITO/Eu(TTA)_3(phen)/AI, glass substrate/ITO/TPD/Eu(TTA)_3(phen)/AI and glass substrate/ITO/TPD/Eu(TTA)_3(phen)/AIQ_3AI$ structures were fabricated by vacuum evaporation method, where aromatic diamine(TPD) was used as a hole transporting material, $Eu(TTA)_3(phen)$ as an emitting material, and Tris(8-hydroxyquinoline)Aluminum$(AlQ_3)$ as an electron transporting layer. Electroluminescent(EL) and current density-voltage(J-V) characteristics of these OELDs with various thickness of $Eu(TTA)_3(phen)$ layer were investigated. The triple-layer structure devices show the red EL spectrum at the wavelength of 613nm, which is almost the same as the photoluminescent(PL) spectrum of $Eu(TTA)_3(phen)$.It was found from the J-V characteristics of these devices that the current density is not dependent on the applied field, but on the electric field.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.957-964
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• 2010

The deactivated catalyzed diesel particulate filter-trap (DPF) was remanufactured by ultrasonic wave treatment with various prepared solutions, followed by active component re-impregnation, and the emission control performance and surface properties of remanufactured DPF were studied at various remanufacturing conditions. The proper ultrasonic wave cleaning time at various prepared solutions and optimal re-impregnation amounts of active component for the best emission control performance of DPF were investigated and its performance tests were also carried out with various temperatures for the conversions of CO, THC (total hydrocarbon) and PM (particulate matter) by catalytic reaction test unit using bypass gas from the diesel engine dynamo system. It was found that the emission control performance of DPF remanufactured with the high-temperature air washing, ultrasonic wave cleaning at acid/base solutions and active component re-impregnation method was recovered to 95% level of its activity compared to that of the fresh DPF, which was caused by removing the deactivating materials from the surface of the DPF, through the analyses of performance test and their surface characterization by Optical microscope, EDX, ICP, TGA, and porosimeter.

• Applied Biological Chemistry
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• v.22 no.3
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• pp.166-172
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• 1979

A series of experiments was planned for practical application of rhizobia in grass lands in Korea. This is the report for the studies mainly on the isolation and characterization of alfalfa nodule bacteria, and on the assessment of their nodulation abilities and nitrogen fixation capacities. 1. Total number of 47 strains was isolated from nodules which were taken from alfalfa grown in Daekwanyong, Cheju and other places. 2. Morphological and cultural characteristics of the strains were studied, and attempts. were also made to investigate their antigenic properties and to demonstrate lysogenic strains. The results were; i) the isolates varied in their cultural characteristics on yeast mannitol broth and agar, and in degree of congo red absorption; ii) similarities in their antigenic prorerties were found between the strains: SU 47/M-11, M-13/M-15, and M-3/M-5; iii) no lysogeny was found in the strains. 3. Plant infection test by test tube method in light room were carried out to elucidate the ability of the strains to nodulate Luna alfalfa and of the capacity of such nodules to fix atmospheric nitrogen. The isolates were grouped info non-invasive, ineffective, or effective to the legumes. Those strains which produced effective nodules, supporting similar/higher level of growth as nitrate control were: M-8, 9, 14, 20, 21, 25 and 34.

• Polymer(Korea)
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• v.28 no.5
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• pp.382-390
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• 2004

One of the significant natural bioactive materials is demineralized bone particle (DBP) whose has a powerful induce. of new bone growth. In this study, we developed the DBP loaded poly-lactide (PLA) and poly(L-lactide-co-glycolide) (PLGA) scaffolds for the possibility of the application of the tissue engineered bone. PLA/DBP and PLGA/DBP scaffolds were prepared by solvent casting/salt leaching method and were characterized by porosimeter, scanning electron microscopy. BMSCs were stimulated by osteogenic medium and characterized by histological stained Wright-Giemsa, Alizarin red, von Kossa, and alkaline phosphate activity (ALP). DBP impregnated scaffolds with BMSCs were implanted into the back of athymic nude mouse to observe the effect of DBP on the osteoinduction compared with control scaffolds. It can be observed that the porosity was above $90.2\%$ and the pore size was above 69.1$\mu$m. BMSCs could be differentiated into osteoprogenitor cells as result of wright-giemsa, alizarin red, von Kossa and ALP staining. In in vivo study, we could observed calcification region in PLA/DBP and PLGA/DBP groups, but calcification did not occur almost in control scaffolds. From these results, it seems that DBP as well as BMSCs play an important role for bone induction in PLA/DBP and PLGA/DBP scaffolds.

• Polymer(Korea)
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• v.35 no.4
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• pp.350-355
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• 2011

A soluble polyamide containing photosensitive l,4-phenylenediacrylic acid (PDA) in main chain with biphenyl moiety was synthesized. The chemical structure of synthesized polyamide was investigated by means of $^1H$ NMR spectroscopy. The polymer was stable up to $280^{\circ}C$ and soluble in organic solvents, giving a good quality of thin films. The photoreaction of unpolarized LTV irradiated films was investigated by means of UV-vis absorption spectroscopy and FTlR spectroscopy, and liquid crystals (LCs) alignment property was examined by exposing to linearly polarized UV light (LPUVL) of 260~380 nm. The polyamide in film has excellent photoreactivity to unpolarized UV light. Direction selective photoreaction of PDA moiety in Lhe film was found to further induce nematic liquid -crystals to align along a perpendicular direction with respect to the electric vector of LPUVL, regardless of exposure energy of LPUVL. In addition, pretilt angle was measured by means of crystal rotation method. LPUVL-exposed polymer film induced the alignment of liquid-crystals (LC) with a pretilt angle of 0.2~$0.5^{\circ}$.

• Journal of Korea Water Resources Association
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• v.41 no.10
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• pp.995-1007
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• 2008

Studies on modeling the rainfall-runoff relationship which shows nonlinear trend strongly use artificial neural networks theory not only for the prediction but also for the characteristics analysis of the data used by pattern classification. For the pattern classification, the results from Self-Organizing Map (SOM) mention that the map size and array for the SOM training have significantly influenced on the SOM performance. Since there is no deterministic method or theoretical equation to determine the number of rows and columns for the map size, hexagonal array is generally used for the map array. Therefore, this study present a determination of the optimized map structure for the rainfall-runoff analysis in Naju station considering the map size and array simultaneously which can represent the classified characterization of rainfall-runoff relationship. The result showed that the map size of 20$\times$16 hexagonal array with 8-clustered patterns was selected as an appropriate map structure for rainfall-runoff analysis in Naju station.

• Korean Journal of Microbiology
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• v.47 no.4
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• pp.308-315
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• 2011

The purpose of this work was to examine the antimicrobial activity derived from the lactic acid bacterium, UK-3 isolated from the vaginas of women of childbearing age. Various physiological and biochemical properties of this strain were characterized. Both the BIOLOG system and phylogenetic analysis using 16S rRNA sequencing were utilized for identification, and the strain was designated as Lactobacillus plantarum UK-3, and registered in GenBank as [JK266589]. Growth rate, production of organic acids (e.g., lactic acid and acetic acid), and pH during growth were monitored. The maximum concentrations of lactic acid and acetic acid were approximately 684.11 mM and 174.26 mM, respectively, and pH changed from 7.0 to 3.7 after 72 h of incubation. High performance liquid chromatography was used to confirm lactic acid and acetic acid production. Significant antimicrobial activity of the concentrated supernatant was demonstrated against various Gram-positive (e.g., Staphylococcus aureus, Staphylococcus epidermidis, Methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, Neisseria species., Listeria monocytogenes), Gram-negative bacteria (e.g., Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis), and yeast (e.g., Candida albicans) by the plate diffusion method. As a result, the concentrated L. plantarum UK-3 cultures had lower acidity and inhibited the growth of all microorganisms tested, whereas the growth of L. acidophilus was not affected.