• The Korean Journal of Physiology and Pharmacology
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• v.20 no.5
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• pp.507-514
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• 2016

Although 3D-complex fractionated atrial electrogram (CFAE) mapping is useful in radiofrequency catheter ablation for persistent atrial fibrillation (AF), the directions and configuration of the bipolar electrodes may affect the electrogram. This study aimed to compare the spatial reproducibility of CFAE by changing the catheter orientations and electrode distance in an in -silico left atrium (LA). We conducted this study by importing the heart CT image of a patient with AF into a 3D-homogeneous human LA model. Electrogram morphology, CFAE-cycle lengths (CLs) were compared for 16 different orientations of a virtual bipolar conventional catheter (conv-cath: size 3.5 mm, inter-electrode distance 4.75 mm). Additionally, the spatial correlations of CFAE-CLs and the percentage of consistent sites with CFAE-CL<120 ms were analyzed. The results from the conv-cath were compared with that obtained using a mini catheter (mini-cath: size 1 mm, inter-electrode distance 2.5 mm). Depending on the catheter orientation, the electrogram morphology and CFAE-CLs varied (conv-cath: $11.5{\pm}0.7%$ variation, mini-cath: $7.1{\pm}1.2%$ variation), however the mini-cath produced less variation of CFAE-CL than conv-cath (p<0.001). There were moderate spatial correlations among CFAE-CL measured at 16 orientations (conv-cath: $r=0.3055{\pm}0.2194$ vs. mini-cath: $0.6074{\pm}0.0733$, p<0.001). Additionally, the ratio of consistent CFAE sites was higher for mini catheter than conventional one ($38.3{\pm}4.6%$ vs. $22.3{\pm}1.4%$, p<0.05). Electrograms and CFAE distribution are affected by catheter orientation and electrode configuration in the in-silico LA model. However, there was moderate spatial consistency of CFAE areas, and narrowly spaced bipolar catheters were less influenced by catheter direction than conventional catheters.

• Journal of the Korea Institute of Building Construction
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• v.18 no.6
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• pp.507-515
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• 2018

The purpose of this research is to develop a slurry-type accelerator that contains various beneficial properties such as reduction of dust generation, lower alkalinity, early age strength development, etc., and uses such slurry type accelerator to produce high performance shotcrete that present excellent resistant against chloride ion penetration. In this work, shotcrete mixtures of 0.44 and 0.338 water-to-binder ratio (w/b) were produced at construction site using slurry-type accelerator. The mechanical properties and chloride ion penetration resistance of such shotcrete (including base concrete) were evaluated. According to the experimental results, the slurry-type accelerator was successfully used to produce both w/b 0.44 and 0.338 shotcretes. The 1 day and 28 day compressive strength of shotcrete were found to be closer to or higher than 10MPa and 40MPa, respectively. The w/b 0.338 shotcrete that used 40% replacement of blast furnace slag showed lower compressive strength than w/b 0.44 shotcrete without any mineral admixture at 1 day. However, the compressive strength with 40% blast furnace slag increased significantly at 28 day. Moreover, there was more than 50% increase in chloride ion penetration resistance with blast furnace slag, showing its strong potential for higher performance shotcrete application.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.507-516
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• 2018

The closed chamber method, which is one of the most commonly used method for measuring greenhouse gases produced in rice paddy fields, has limitations in measuring dynamic $CH_4$ flux with spatio-temporal constrains. In order to deal with the limitation of the closed chamber method, some studies based on open-path of eddy covariance method have been actively conducted recently. The aim of this study was to compare the $CH_4$ fluxes measured by open-path and closed chamber method in the paddy rice fields. The open-path, one of the gas ($CO_2$, $CH_4$ etc.) analysis methods, is technology where a laser beam is emitted from the source passes through the open cell, reflecting multiple times from the two mirrors, and then detecting. The $CH_4$ emission patterns by these two methods during rice cultivation season were similar, but the total $CH_4$ emission measured by open-path method were 31% less than of the amount measured by closed chamber. The reason for the difference in $CH_4$ emission was due to overestimation by closed chamber and underestimation by open-path. The closed chamber method can overestimate $CH_4$ emissions due to environmental changes caused by high temperature and light interruption by acrylic partition in chamber. On the other hand, the open-path method for eddy covariance can underestimate its emission because it assumes density fluctuations and horizontal homogeneous terrain negligible However, comparing $CH_4$ fluxes at the same sampling time (AM 10:30-11:00, 30-min fluxes) showed good agreements ($r^2=0.9064$). The open-path measurement technique is expected to be a good way to compensate for the disadvantage of the closed chamber method because it can monitor dynamic $CH_4$ fluctuation even if data loss is taken into account.

• Journal of The Korean Association For Science Education
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• v.19 no.4
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• pp.507-515
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• 1999

This study is to develope the performance scoring rubrics for the inquiry-based experiments of general chemistry course in the college of education. Two types of analytic scoring rubrics have been developed for nine different experiments. The first one is to assess scientific process skills from the written experimental reports. These analytic scoring rubrics include seven process skills selected from the Lawson's 'creative and critical thinking skills' and other known process skills. The second one is to assess the individual manipulative skills and experimental attitudes through direct observations by the teacher. The content validity of all scoring rubrics was testified by six science educators. Also the inter-scorer reliability of analytic scoring rubrics administered on the students' experimental reports was examined. The correlation coefficient between the scores obtained from the experiments and those of the written test for theoretical knowledges was found to be r=.663(p <.01). From the variance($r^2$=.440), we would say indirectly that the 56% of this experimental assessment does not overlap with the theoretical knowledges test and assesses students' science process skills, manipulative skills, and attitudes.

• Restorative Dentistry and Endodontics
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• v.34 no.6
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• pp.500-507
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• 2009

The purpose of this study is to compare the antibacterial effect of $Listerine^{(R)}$ on two microorganisms (P. gingivalis and E. faecalis) with various root canal irrigants (NaOCl, CHX, EDTA) and to identify possibility of using $Listerine^{(R)}$ as a root canal irrigant. Porphyromonas gingivalis ATCC 3327 and Enterococcus faecalis ATCC 29212 were used in this experiment. For the test irrigants, 0.5%, 1%, 2.5%, 5.25% NaOCl, 0.1%, 0.2%, 1%, 2% CHX, 0.5M EDTA (18.6% EDTA) and $Listerine^{(R)}$ were prepared. Distiled water was used as control. Two methods-1) Comparison of turbidity in broth and 2) Agar diffusion test-were used to determine the extent of antibacterial effect of $Listerine^{(R)}$ and to compare it with that of NaOCl, CHX, and EDTA. All solutions tested were effective against two bacterial strains compared with control (p < 0.001). Any concentration of NaOCl, CHX, and EDTA showed similarly high effectiveness against all bacterial strains. In all experiment, $Listerine^{(R)}$ showed significantly low antibacterial effect compared with the other root canal irrigants (p < 0.05). In conclusion, the results reflect remarkably low antibacterial effect of $Listerine^{(R)}$ as compared with root canal irrigants in general so it is not suitable for the root canal irrigant.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.67-75
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• 2012

Purpose: The study is to check the specialty of radiotherapists working in the department of radiation oncology and find job satisfaction, organizational commitment and job commitment having an effect on professional parts. After making analysis of the mutual relation, it is to provide radiotechnologists with making progress in the future. Materials and Methods: From March 2 to March 30, we had carried out a survey with email. It is possible to have 272 questionnaires answered in the survey. We make use of SPSS 13.0 for Windows to analyze the data collected for study. Frequency and a percentage are meant to show general characteristics, and t-test and ANOVA to do the difference between general properties and professionalism. Pearson's correlation coefficient also is meant to do the correlation of professionalism, organizational job commitment and job satisfaction, and multiple regression analysis to do the factor for a relevant variable to affect professionalism. Results: There are subdivisions in the professionalism informing us of the self-regulation $17.74{\pm}2.32/3.55{\pm}.46$, a sense of calling $17.58{\pm}2.63/3.52{\pm}.53$, reference of the professional $17.14{\pm}2.39/3.43{\pm}.48$, service to the public $15.97{\pm}2.48/3.19{\pm}50$, and autonomy $15.68{\pm}2.28/3.14{\pm}46$. Grand mean turns out to be $83.89{\pm}7.63$(Summation of items)/$3.37{\pm}0.49$ (Numbers of items). When it comes to a statistical relation between general characteristics and professionalism, the statistics have it that these come within age (P<.001), period of employment (P<.001), education status (P<.05), a monthly income (P<.001), radiotherapists who get a special license (P<.001), the position (P<.001), and an opportunity for developing (P<.001). As a result of organizational commitment, job commitment, and job satisfaction, grand mean in organizational commitment proves to be $80.10{\pm}8.15/3.34{\pm}.34$. There are subvisions showing affective commitment $28.64{\pm}4.61$/3.58, continuance commitment $27.54{\pm}4.22/3.44{\pm}.53$, and normative commitment $23.95{\pm}2.94/2.99{\pm}.37$ in order of precedence. The average grade in job commitment is $32.47{\pm}5.77/3.30{\pm}.60$ and that in job satisfaction is $63.39{\pm}10.16/3.17{\pm}.51$, respectively. We find the positive relationship between professionalism and organizational commitment (r=.522, P<.05), between professionalism and job commitment (r=.444, P<.05), and between professionalism and job satisfaction (r=.507, P<.05). And we also get the positive relationship between organizational commitment and job commitment (r=.549, P<.05), between organizational commitment and job satisfaction (r=.433, P<.05), and between job commitment and job satisfaction (r=.462, P<.05). To catch the factors influencing the professionalism of radiotherapists, we used multiple regression analysis. According to the final model, it appears affective commitment (B=.755, P<.05), normative commitment (B=.305, P<.05), job satisfaction (B=.092, P<.05), an opportunity for developing (B=-1.505, P<.05), and the position (B=-1.155, P<.05) in order of precedence. It seems that explaining influece on $R^2$ is 0.504. Conclusion: The results of the factors that influence professionalism working as radiotherapists in the department of radiation oncology have it that the more affective commitment, normative commitment, and job satisfaction we feel, the more professionalism we recognize. We think that the focus of professionalism is increased if getting the chances for radiotherapists to have little to do with developing opportunities given.

• Korean Journal of Poultry Science
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• v.6 no.2
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• pp.75-81
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• 1979

This study was carried out to select superior dual purpose hens which could spread to poultry farming for subsidiary work and general farmhouse. Three hundred and fifty chicks of 7 kinds of 2-way crossbred from mating of Rhode Island Red, New Hampshire and Australorps were tested for dual purpose performance. The results obtained were as follows: 1. The average viability of brooding, rearing and laying Period hen were 92.3% 98.3% and 93.1% respectively. There was significant difference at 1% level among crossbreds for brooding viability, but other viabilitys were no significant difference. 2. The average body weight of 8 weeks was 854.41g, but there was no significant difference among crossbreds, respectively. Average body weight at 300 days, 500 days were 2507.15g, 2632.25g respectively, but there was significant difference at 1% level among crossbreds. 3. Sexual maturity of individual and 50% egg production were 173.7 days and 199.4 days, respectively. There was significant difference at 5% level among crossbreds. 4. The average hen day egg production was 65.3% and the highest was R.N crossbred (70.5%). There was significant difference at 5% level among crossbreds and average hen housed egg Production was 20.2 eggs and the highest was 220.4 eggs in R.A. crossbred. 5. The average egg weight was 57.36g and the highest was A.N crossbred (58.3g). Therc was no significant difference among crossbreds. 6. The average feed consumption per hen per day by stag. was 42.9g (brooding period), 83.7g (rearing period), 131.1g (laying period). Average feed requirement per 1kg. egg production was 3.79 and th. R.A. crossbred was superiority (3.42). 7. On the basis of the results of this study, the R.A and R.N crossbreds were best for superior dual commercial chicks under farming management conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.389-398
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• 2018

This study examined the influence of problem solving ability, communication skill and self-efficacy on clinical competence of nursing students. The research subjects were 184 grade 4 nursing students in D and G city. Data were collected from September 1 to September 10, 2016 and analyzed by independent t-test, one-way ANOVA, Pearson's correlation, and stepwise multiple regression using the IBM SPSS/WIN 20.0 program. The results showed that the problem solving ability was 3.60, communication skill was 3.79, and self-efficacy was 3.45. The clinical competence was positively correlated with problem solving ability, communication skill and self-efficacy. Problem solving ability (${\beta}=0.283$, p<0.001), self-efficacy (${\beta}=0.249$, p<0.001), motivation for nursing (${\beta}=0.182$, p=0.002), communication skills (${\beta}=0.176$, p=0.016), and interpersonal relationships (${\beta}=0.101$, p=0.082) explained 42.8% of the total variance in clinical competence of nursing students. The most significant predictors of clinical competence were problem solving ability, followed by self-efficacy and communication skills. Therefore, it is necessary to develop an empowerment program to improve problem solving ability, self-efficacy and communication skills of nursing students.

• Journal of radiological science and technology
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• v.39 no.4
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• pp.501-507
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• 2016

This study is to figure out the amount of primary X-ray generated in SID 50cm, 1m, and 2m penetrating protective aprons in X-ray radiography for hands, skull, and lumbar spine. Results are as follows: Firstly, the exposure dose of primary X-ray which is low such as that of hand X-ray may be reduced by 270 times if protective aprons are worn, but it still slightly penetrates 0.3mm thick Pb protective aprons at SID 50cm, 1m, and 2m. Secondly, the exposure dose of primary X-ray which is moderate such as that of skull X-ray may be reduced by 22 times if protective aprons are worn, but it still fairly penetrates 0.3mm thick Pb protective aprons at SID 50cm, 1m, and 2m. Thirdly, the exposure dose of primary X-ray which is very high such as that of lumbar spine X-ray may be reduced by 13 times if protective aprons are worn, but it still penetrates a lot 0.3mm thick Pb protective aprons at SID 50cm, 1m, and 2m. Therefore, people in X-ray room should not only wear protective aprons at any spaces that the primary X-ray can reach, but also need to stand behind the thick Pb shield to protect the body if it is inevitable to stay in the room.

• Applied Chemistry for Engineering
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• v.27 no.5
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• pp.502-507
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• 2016

This study was conducted to develop novel antimicrobial nano-composites, with the aim of fully utilizing antimicrobial properties of multi-walled carbon nanotubes (MWCNTs), nickel (Ni) and zinc oxide (ZnO). Ni coated-MWCNTs (Ni-CNT) were prepared and evaluated for their potential application as an antimicrobial material for inactivating bacteria. Field emission scanning electron microscopy (FE-SEM), and X-ray energy dispersive spectroscopy (EDS) were used to characterize the Ni coating and morphology of Ni-CNT. Staphylococcus aureus (S. aureus) and Escherichia coil (E. coil) were employed as the target bacterium on antimicrobial activities. Comparing with the nitric acid treated MWCNTs and Ni-CNT which have been previously reported to possess antimicrobial activity towards S. aureus and E. coil, Ni-CNT/ZnO exhibited a stronger antimicrobial ability. The nickel coating was confirmed to play an important role in the bactericidal action of Ni-CNTs/ZnO composites. Also, the addition of ZnO to the developed nanocomposite is suggested to improve the antimicrobial property.