• The Journal of Korean Physical Therapy
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• v.18 no.3
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• pp.37-45
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• 2006

Purpose: This study analyzed changes in spinal neuron and action potential of motor unit depending on voluntary contraction on spinal neuron adaptation. Methods: It selected 80 university students in their twenties and divided into experimental groups of 25% MVIC (I), 50% MVIC (II), 75% MVIC (III) and 100% MVIC (IV) depending on maximum voluntary isometric contraction (MVIC) and performed isometric exercise of plantar flexor muscle to each experimental group with given contraction for 20 times. It measured Mmax, H/Mmax, Hmax latency, V/Mmax, V wave latency before and after exercise, compared method and volume of contraction. Results: H/Mmax ratio showed significant difference in comparison among groups (p<0.01) and there was difference in I and IV groups. V/Mmax ratio showed significant difference in comparison among experimental groups (p<0.05) and there was difference in I and IV groups. When voluntary contraction level was maximum, changes were greatest. However, no significantly difference was to Mmax, H latency and V wave latency. Conclusion: These results suggest that amplitude changes of voluntary contraction level, spinal neuron and supra-spinal neuron had a dose connection that the more contraction level, the better central activation seem to decrease highly for a short time.

• Journal of Mechanical Science and Technology
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• v.18 no.12
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• pp.2182-2189
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• 2004

In the recent years, environmentally conscious design and manufacturing technologies have attracted considerable attention. The coolants, lubricants, solvents, metallic chips and discarded tools from manufacturing operations will harm our environment and the earth's ecosystem. In the present work, the Tukey method of multiple comparisons is used to select the minimum level of coolant required in a turning process. The amount of coolant is varied in 270 designed experiments and the parameters cutting temperature, surface roughness, and specific cutting energy are carefully evaluated. The effects of coolant mix ratio as well as the amount of coolant on the turning process are studied in the present work. The cutting temperature and surface roughness for different quantity of coolant are investigated by analysis of variance (ANOVA) - test and a multiple comparison method. ANOVA-test results signify that the average tool temperature and surface roughness depend on the amount of coolant. Based on Tukey's Honestly Significant Difference (HSD) method, one of the multiple comparison methods, the minimum level of coolant is 1.0 L/min with 2% mix ratio in the aspect of controlling tool temperature. F-test concludes that the amount of coolant used does not have any significant effect on specific cutting energy. Finally, Tukey method ascertains that 0.5 L/min with 6% mix ratio is the minimum level of coolant required in turning process without any serious degradation of the surface finish. Considering all aspects of cutting, the minimum coolant required is 1.0 L/min with 6% mix ratio. It is merely half the coolant currently used i.e. 2.0 L/min with 10% mix ratio. Minimal use of coolant not only economically desirable for reducing manufacturing cost but also it imparts fewer hazards to human health. Also, sparing use of coolant will eventually transform the turning process into a more environment-conscious manufacturing process.

• Journal of Digital Convergence
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• v.15 no.6
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• pp.535-543
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• 2017

This study aimed to improve the satisfaction of multi-cultural children by encouraging their participation in healthy exercises, and confirm the level of changes in their school life, the satisfaction with happiness. In order to achieve this purpose, dividing the participants in this program into an experimental group of 20 who participate in taekwondo training program and a comparison group of 20 who do not do sports activity, the study was conducted with a binary mixed design by three repeated measures by group. The conclusions made through these measures were as follows: According to the measurement time between the experimental group who participated in taekwondo training program and the comparison group who did not do sports activity, there were differences in changes in satisfaction of school life, leisure satisfaction, and satisfaction with happiness. Namely, the change in the experimental group was more than that of the comparison group. In conclusion, for multi-cultural children, it can be assessed that as the duration of participation in the taekwondo training program increases, the effect was clear, and it was found that satisfaction of school life, leisure satisfaction, and happiness satisfaction have changed statistically and significantly.

• The Plant Pathology Journal
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• v.36 no.5
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• pp.428-439
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• 2020

Erwinia pyrifoliae is a Gram-negative bacterial plant pathogen that causes black shoot blight in apple and pear. Although earlier studies reported the genome comparison of Erwinia species, E. pyrifoliae strains for such analysis were isolated in 1996. In 2014, the strain E. pyrifoliae EpK1/15 was newly isolated in the apple tree showing black shoot blight in South Korea. This study aimed to better understand the similarities and differences caused by natural variations at the genomic level between newly isolated E. pyrifoliae EpK1/15 and the strain Ep1/96, which were isolated almost 20 years apart. Several comparative genomic analyses were conducted, and Clusters of Orthologous Groups of proteins (COG) database was used to classify functional annotation for each strain. E. pyrifoliae EpK1/15 had similarities with the Ep1/96 strain in stress-related genes, Tn3 transposase of insertion sequences, type III secretion systems, and small RNAs. The most remarkable difference to emerge from this comparison was that although the draft genome of E. pyrifoliae EpK1/15 was almost conserved, Epk1/15 strain had at least three sorts of structural variations in functional annotation according to COG database; chromosome inversion, translocation, and duplication. These results indicate that E. pyrifoliae species has gone natural variations within almost 20 years at the genomic level, and we can trace their similarities and differences with comparative genomic analysis.

• Development and Reproduction
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• v.21 no.4
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• pp.417-424
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• 2017

Alzheimer's disease (AD) is neurodegenerative disease, characterized by the progressive decline of memory, cognitive functions, and changes in personality. The major pathological features in postmortem brains are neurofibrillary tangles and amyloid beta ($A{\beta}$) deposits. The majority of AD cases are sporadic and age-related. Although AD pathogenesis has not been established, aging and declining mitochondrial function has been associated. Mitochondrial dysfunction has been observed in AD patients' brains and AD mice models, and the mice with a genetic defect in mitochondrial complex I showed enhanced $A{\beta}$ level in vivo. To elucidate the role of mitochondrial complex I in AD, we used SH-SY5Y cells transfected with DNA constructs expressing human amyloid precursor protein (APP) or human Swedish APP mutant (APP-swe). The expression of APP-swe increased the level of $A{\beta}$ protein in comparison with control. When complex I was inhibited by rotenone, the increase of ROS level was remarkably higher in the cells overexpressing APP-swe compared to control. The number of dead cell was significantly increased in APP-swe-expressing cells by complex I inhibition. We suggest that complex I dysfunction accelerate amyloid toxicity and mitochondrial complex I dysfunction in aging may contribute to the pathogenesis of sporadic AD.

• Nutrition Research and Practice
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• v.3 no.1
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• pp.49-55
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• 2009

This study investigated the management importance and performance level of foodservice managers at senior centers. Using the survey, perceived importance and performance levels of seven foodservice management areas were evaluated and analyzed. Data showed the foodservice facilities were being managed by dietitians (61.6%) or non-dietitians (38.9%). The result indicated that overall importance level (3.43) was higher than performance level (3.02) (p<.01). As of the IPA result, dietitians and non-dietitians had different perspectives in terms of managing the eight categories of foodservice areas. The differences in the IPA results between the two groups may reflect bias attributable to the respondents' degrees of knowledge and professional preparation. The research findings could enhance our understanding of importance of hiring professional dietitians to operate foodservice at senior centers and find out which management area should be concentrated for more effective foodservice management.

• Journal of the Korean Society of Earth Science Education
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• v.2 no.1
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• pp.55-61
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• 2009

This study was designed to explore problem solving process to earth science area by elementary science gifted children, which compared and analyzed the questionnaires and problem solving to earth science area by gifted Science education center, Seoul National University Of Education, The analyzed results showed difference by gender that in the science study level at the time of entrance to the gifted Science education center, male students was the highest in the middle school as 37.5%, and female students in the elementary 6th grade as 61.5%. And male students were investigated to do more precedent study than female students. Secondly, in the problem solving process of earth science related problems, males made most use of problem solving process area(30.3%), and females symbolizing (27.5%) area. Thirdly, comparison of reasoning technology in problem solving process by gender indicated that both sexes made the most use of analytical reasoning (male 62.0%, female 53.6%) to solve problems.

• Wind and Structures
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• v.5 no.2_3_4
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• pp.227-244
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• 2002

Recently, the prediction of wind environment around a building using Computational Fluid Dynamics (CFD) technique comes to be carried out at the practical design stage. However, there have been very few studies which examined the accuracy of CFD prediction of flow around a high-rise building including the velocity distribution at pedestrian level. The working group for CFD prediction of wind environment around building, which consists of researchers from several universities and private companies, was organized in the Architectural Institute of Japan (AIJ) considering such a background. At the first stage of the project, the working group planned to carry out the cross comparison of CFD results of flow around a high rise building by various numerical methods, in order to clarify the major factors which affect prediction accuracy. This paper presents the results of this comparison.

• Health Policy and Management
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• v.28 no.1
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• pp.98-103
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• 2018

This study aims to evaluate the status of Korean healthcare among Organization for Economic Cooperation and Development countries and to monitor the trend of health care status since 2000. The position value for relative comparison (PARC) index was selected to gauge the level of healthcare status in demand, supply, accessibility, quality, and cost as per healthcare policy aspects. The Mann-Kendall test was conducted to allocate healthcare status of Korea since 2000. The PARC values indicate strength and weakness of Korean healthcare system by the mathematical comparisons. Korea positioned higher in demand, supply, accessibility, and quality. Yet, there are shortages in human resources and primary care. In conclusion, we suggest utilizing this study provides evidence to prioritize health care problems that can lead to establishing healthcare policy.

• Journal of Society of Preventive Korean Medicine
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• v.18 no.2
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• pp.59-67
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• 2014

Objective : This study was to examine the effects of Doin-Angyo program, evidenced by East Asian Medicine literatures, on stress among smoking adolescents. Method : This study was a prospective community trial using a one-group, pretest-posttest design. As an intervention, Doin-Angyo program was implemented for 10 minutes per session, 3 days a week, for 6 weeks to smoking students who attend a Girl's high school. Psychological stress was measured by self-report questionnaire and physiological stress was measured by salivary cortisol. The final sample for the questionnaire included 18 participants. In addition, pre- and post-salivary cortisol levels of 24 adolescents participating in the last session were compared in order to identify the acute effects of Doin-Angyo program in reducing stress. Results : There were no significant differences in overall stress-test results from the comparisons before and after the intervention. However, we found a significant going-down of the stress level(p = .032) in the question, "About School-work" among six sub-category questions. From the salivary cortisol tests in the last session, we found, in comparison with the standard salivary cortisol density level, $0.3{\mu}g/dL$, the density level tended to go down(p = .062) when higher than the standard, and it went up(p = .001) when lower than the standard, after 10 minute session. Conclusion : The results of this pilot study supported the partial effect of Doin-Angyo program in reducing the stress levels. The study protocol and results can be used to elaborate the community trials design aiming to prove the effect of Korean Medicine based health promotion modalities.