• Journal of the Korean Society for Railway
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• v.8 no.2
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• pp.170-175
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• 2005

This study presents a prediction of a failure rate in a safety required system that consists of a embedded control system, requiring a satisfaction of a quantitative safety requirement. International Standards are employed to achieve a regular procedures in the whole life cycle of a system, for the purpose of a prediction and a evaluation of a fault that might be able to be happened in a system. This International Standards uses SIL (Safety Integrity Level) to evaluate a safety level of a system. SIL is divided into 4 levels, from level 1 to level 4, and each level has functional failure rate and dangerous failure rate of a system. In this paper we describe the conventional method to predict the dangerous failure rate and propose a method using hazard analysis to predict the dangerous failure rate. The conventional method and the technique using hazard analysis to predict the dangerous failure rate are made a comparison through the control modules of the interlocking system in KTX. The proposed method verify better effectiveness for the prediction of the dangerous failure rate than that of the conventional method.

• Journal of the Korean Society of Visualization
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• v.19 no.1
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• pp.74-80
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• 2021

Cells regulate their shapes and motility by sensing the cues from the internal and external microenvironment. Under different circumstances, microglia, the brain resident immune cells, undergo dynamic phenotypic changes, one of which is a remarkable periodic oscillatory migration in vitro. However, very little is known about the kinematic and dynamic perspectives of this oscillatory behavior. In this study, we tracked the changes in cell morphology and nuclear displacement, and visualized the forces using traction force microscopy (TFM). By correlation analyses, we confirmed that the lamellipodia formation preceded the nuclear translocation. Moreover, traction, developed following lamellipodia formation, was found to be localized and fluctuated at two ends of the oscillating cells. Taken together, our results imply that oscillatory microglial cells feature a viscoelastic migration, which will contribute to the field of cell mechanics.

• Journal of Korean Academy of Nursing
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• v.43 no.3
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• pp.305-311
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• 2013

Purpose: The purpose of this study was to compare the effect of alcohol gel according to the amount and drying time in health personnel hand hygiene and to promote in their practice adequate and effective hand hygiene. Methods: The crossover experimental study was performed with 14 volunteers. Hands were artificially contaminated with 5 mL of $10^8$ CFU/mL of Serratia marcescens (ATCC 14756) and four different alcohol gel hand hygiene methods varying by the amount of alcohol gel (2 mL vs. 1 mL) and drying time (complete vs. incomplete) were compared. Samples were collected by glove juice sampling procedures. Results: Mean log reduction values of the four different hand hygiene methods were $2.22{\pm}0.36$, $1.26{\pm}0.53$, $1.49{\pm}0.60$, $0.89{\pm}0.47$ respectively for the 4 groups: adequate amount (2mL) and complete dry (30 seconds rubbing followed by 2 min air-dry), inadequate amount (1 mL) and complete dry, adequate amount and incomplete dry (15 seconds rubbing and no air-dry), and inadequate amount and incomplete dry. The difference was statistically significant in the adequate amount and complete dry group compared to other three groups (p<.001). Conclusion: Only alcohol gel hand hygiene with adequate amount and complete drying was satisfactory by U.S. FDA-TFM efficacy requirements for antiseptic hand hygiene products.

• Journal of the Korean Society of Visualization
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• v.13 no.1
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• pp.43-48
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• 2015

Collective cell migration is a fundamental phenomenon observed in various biological processes such as development, wound healing, and cancer metastasis. During the collective migration, cells undergo changes in their phenotypes from those of stable to the migratory state via the process called epithelial-mesenchymal transition (EMT). Recent findings in biology and biochemistry have shown that EMT is closely related to the cancer invasion or metastasis, but not much of the correlations in kinematics and physical forces between the neighboring cells are known yet. In this study, we aim to understand the cell migration and stress distribution within the expanding cell cluster. We constructed the in vitro cell cluster on the hydrogel, employed traction force microscopy (TFM) and monolayer stress microscopy (MSM) to visualize the physical forces within the expanding cell monolayer. During the expansion, cells at the cluster edge exhibited enhanced motility and developed focal adhesions that are the essential features of EMT while cells at the core of the cluster maintained the epithelial characteristics. In the aspect of mechanical stress, the cluster edge had the highest traction force of ~90 Pa directed toward the cluster core, which means that cells at the edge actively pull the substrate to make the cluster expansion. The cluster core of the tightly confined cells by neighboring cells had a lower traction force value (~60 Pa) but the highest intercellular normal stress of ~800 Pa because of the accumulation of traction from the edge of the monolayer.

• YAKHAK HOEJI
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• v.39 no.3
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• pp.276-282
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• 1995

Compared to the first and second-generation cephalosporins, the third-generation cephalosporins are remarkably stable against hydrolysis by the $\beta$-lactamases produced by aerobic gram-negative bacilli, such as Enterobacteriaceae. Among these bacteria, the most prevalent plasmid-encoded $\beta$-lactamase is TEM-1 $\beta$-lactamase belonging to class A or group 2b. This enzyme is produced constitutively and is principally active against peniciflins and old cephalosporins rather than third-generafion cephalosporins, carbapenems and mmobactams. However, new TEM type $\beta$-lactamases including TEM-9 and TEM-12 evolved through point mutations in a gene encoding $\beta$-lactamase have been discovered from patients during chemotherapy. These $\beta$-lactamases are known to be capable of hydrolyzing most of the third-generatim cephalosporins. To study the prevalence of $\beta$-lactamases from clinical isolates collected in Korea. the minimal inhibitory concentratims(MICs) of several third-generation cephalosporins against 628 clinical isolates were determined by agar dilution methods, and $\beta$-lactamas-producing bacteria were isolated by use of cefinase disc. By polymerase chain reaction (PCR) method, clinical isolates harboring a gene for TEM type $\beta$-lactamase were identified among the $\beta$-lactamase producing strains. Twentiy three percent of the clinical isolates was resistant to the thirdgeneration cephalosporins, and more than 90% of resistant cells produced various $\beta$-lactamases. TFM type $\beta$-lactamases were dominant in gram-negative bacilli, such as Escherichia coli, Klebsiella pneumoniae, Enterobacter species. These results suggest the necessity of the development of new cephalosporins which are stable against $\beta$-lactamases like TEM.

• Korean Journal of Food Science and Technology
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• v.40 no.3
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• pp.343-348
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• 2008

The ovomucoid (OM) of egg whites is recognized as a major allergen. Here, the allergenicity of OM in egg whites (EW) treated by chemical, enzymatic, and physiological methods were investigated by competitive inhibitory ELISA using human IgE antibody acquired from egg-allergic patients. Enzymatic hydrolysis, irradiation, and succinic anhydride treatments did not reduce the allergenicity of the OM effectively. Allergenicity was reduced to only 1/20 by deglycosylation with trifluoromethanesulfonic acid (TFMS). Heat treatment of the OM at $121^{\circ}C$ for 10 min reduced allergenicity to 1/100. Furthermore, NaOH (over 3%) treatment reduced allergenicity to 1/10,000, and the combinatory treatment of NaOH (over 0.3%) and heat ($70^{\circ}C$, 15 min) reduced it to less than 1/10,000, which was the most effective method. In this study, which analyzed treated EW using ELISA and patient-derived IgE, the OM allergenicity was nearly the same as its antigenicity according to ELISA using rabbit IgG. However, in the case of the TFMS-treated EW, the antigenicity was much lower than the allergenicity. These results suggest that the allergenicity of OM is slightly different from its antigenicity.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.2
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• pp.187-193
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• 2017

This study evaluated tidal stream energy resources according to tidal flow properties around Uido off the west coast of, Jeollanam-do, South Korea. A feasibility study was first carried out through the collection of bathymetry data and tidal phase information. For this simulation, a depth-averaged 2D ADCIRC (Advanced Circulation) model for real sea situations was applied to a Finite Element Method (FEM) approach for tides given the variation of tidal current speed. Hydrodynamics were simulated with 4 major tidal constituents (M2, S2, K1, and O1) after setting up 4 observation points. From the real depth-averaged model simulation results, it was found that the spring tide Higher High Water (HHW) and tidal current speed values at the 4 observation points were about 2.2 m and 1.33 m/s, respectively. The ADCIRC model results were analyzed with reference to the Korea Hydrographic and Oceanographic Agency's (KHOA) observed data for verification. Furthermore, using topographical characteristics via the Tidal Flux Method (TFM), tidal energy density distribution was calculated, indicating a maximum tidal energy density of about $1.75kW/m^2$ for the 5 assessment areas around Uido. The tidal energy density was evaluated with consideration given to topographical characteristics as well as tidal elevation and tidal current speed to determine an optimum tidal farm candidate.

• Korean Journal of Agricultural Science
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• v.2 no.2
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• pp.357-373
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• 1975

This study was conducted to evaluate the winter active polycross progenies of 10 genotypes selected at the hot and dry climate of the Southern Oregon in their performance in the progeny test comparing with a high yielding variety, 'Fawn', and a winter active variety, 'TFM', as the control varieties at Daejon, Korea. Various plant and leaf characteristics, especially which related to photosynthesis, and forage production during the first summer after their establishment, were examined. The important conclusions of this study are summarized as follows: 1. The winter active genotypes and variety had less leaf fresh weight and dry weight per leaf than variety 'Fawn'. Variations among polycross progenies of genotypes for these characteristics were great. 2. The winter active genotypes and variety had less leaf area per leaf than variety 'Fawn'. Leaf area among polycross progenies of genotypes deviated greatly and poly cross progenies of 'genotype-16' had the same average leaf area as 'Fawn'. 3. Differences of specific leaf weight (S. L. W.) in the winter active genotypes and variety were not significant. Probably the genetic diversity for S. L. W were not big and were narrowed down already in this genetic population. It was suggested that the photosynthate production within the population might not be different and there might be differences in the photosynthate production-translocation balance. Further study for the diurnal change in S. L. W. within the population might be useful. 4. The winter active variety and genotypes had less leaf width than 'Fawn' does. Leaf width among polycross progenies of genotypes deviated significantly. 5. Differences among controls and polycross progeny group in the initial plant height were significant and variety 'Fawn' was taller than the winter active genotypes and variety. But the differences were not significant in the regrowth of plant height after the first forage harvest. On the contrary. the differences among polycross progenies of genotypes were not significant in the initial plant but the differences in their polycross progeny performance became obvious and great in the regrowth ability which is an improtent agronomic characteristics for forage crops produced in the pasture and for hay and silage. 6. Plant width of the winter active genotypes and variety was lesser than 'Fawn' variety. 7. Differences of tiller number became evident and variety 'Fawn' had higher tiller number than the winter active genotypes and variety after the first forage cutting. There, deviations among polycross progenies of genotypes were great for this characteristic. It was obvious that the genetic differences became more evident in the second measurement after the first cutting of forage probably because this characteristic were stimulated by defoliation in the cartain genotypes and variety. 8. The winter active genotypes and variety on the initial growth. the regrowth ability andtotal yield had lesser forage yield than variety 'Fawn'. Deviation of forage yield among polycross progenies of genotypes were great and gave basis for selection according to their polycross progeny performance improving the forage yield of these winter active tall fescue population during summer. 9. It was concluded that the winter active variety and genotypes in this study was poorer than variety 'Fawn' for the most of leaf and plant characteristics including forage yield. For these measurements, the variations among polycross progenies of genotypes were great. and plant breeding might able to improve further this winter active tall fescue through the polycross progeny testing method for the higher forage production during summer in Korea. 10. The result of the associations among various characteristics under study were quite agreeable with the results of the analysis of variance and woul be useful in the selection of desirable genotypes for the development of a new variety.