• Journal of Preventive Medicine and Public Health
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• v.46 no.2
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• pp.89-95
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• 2013

Objectives: Little is yet known about the determinants of bone mineral density (BMD) in young adults. Thus, in this study, we aimed to determine the factors that have an impact on BMD in young men. Methods: Questionnaires were sent out to 111 male medical students. Information on age, socio-economic status, medical history, lifestyle, physical activity during adolescence, school club participation, current physical activity, and dietary intake were collected by the survey. Height, weight, percent body fat and muscle mass were estimated by bioelectrical impedance, and BMD was obtained using calcaneal quantitative ultrasound. Using the Poisson regression model, prevalence ratios (PRs) were used to estimate the degree of association between risk factors and osteopenia. Results: The height and current physical activity showed a correlation to the Osteoporosis Index. Among the categorized variables, past physical activity during adolescence (p= 0.002) showed a positive effect on the bone mineral content. In the multivariate model, past physical activity (${\geq}1$ time/wk) had a protective effect on osteopenia (PR, 0.37; 95% confidence interval [CI], 0.18 to 0.75) and present physical activity (1000 metabolic equivalent of task-min/wk) decreased the risk of osteopenia (PR, 0.64; 95% CI, 0.44 to 0.91). Conclusions: Past physical activity during adolescence is as important as physical activity in the present for BMD in young men.

• Korean Journal of Applied Biomechanics
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• v.24 no.1
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• pp.43-50
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• 2014

The purpose of this study was to analyze of the GRF (ground reaction force) parameters according to the change of positions and weights of bag during downward stairs between dominant and non-dominant in upper & lower limbs. To perform this study, participants were selected 9 healthy women (age: $21.40{\pm}0.94yrs$, height: $166.50{\pm}2.68cm$, body mass: $57.00{\pm}3.61kg$, BMI: $20.53{\pm}1.03kg/m^2$), divided into 2 carrying bag positions (dominant arm/R, non-dominant arm/L) and walked with 3 type of bag weights (0, 3, 5 kg) respectively. One force-plate was used to collect GRF (AMTI OR6-7) data at a sample rate of 1000 Hz. The variables analyzed were consisted of the medial-lateral GRF (Fx), anterior-posterior GRF (Fy), vertical GRF (Fz), impact loading rate and center of pressure (COPx, COPy, COP area, COPy posterior peak time) during downward stairs. 1) The Fx, Fy, Fz, COPx, and COP area of GRF were not statistically significant between dominant leg and non-dominant leg, but non-dominant leg, that is, showed the higher COPy, and showed higher impact loading rate than that dominant leg during downward stairs. 2) In bag wearing to non-dominant arm, Fx, Fz, COPx, COPy, impact loading rate and COP area showed increase tendency according to increase of bag weights. Also, against bag wearing to dominant arm, non-dominant showed different mechanism according to increase of bag weights. The Ground Reaction Force parameters showed different characteristics according to the positions and weights of bag during downward stairs between dominant and non-dominant arm.

• Journal of Conservation Science
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• v.32 no.3
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• pp.437-448
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• 2016

Studies on vulnerability of cultural heritage and adaptation strategy to worldwide climate change have been actively carried out in advanced countries since the late 20th century, and this established a valid research methodology and piled up climate and deterioration dataset in the field of climate change. Meanwhile, we still have tasks to acquire related scientific data despite referencing political researches in Korea. Applying Korean future climate to impact analysis, deterioration of Korean stone heritage is likely prospected to change into complexity in terms of physical, chemical and biological weathering that may bring impacts on conservation business and administrative field of cultural heritage. Further studies will ensure detailed implication of climate change impact on Korean stone heritage by means of down-scaling analysis of areas to local scale and dataset frequency to an hour. It is important to sort out capability and vulnerability of the stone heritage to future environment, and to make an adaption and prevention strategies.

• Journal of Environmental Science International
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• v.24 no.11
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• pp.1431-1442
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• 2015

This study was carried out to systematically maintain and manage the trails by assessing the physical characteristics, the types of deterioration and impact rating class of trails located in Mt. Nam District of the Gyeongju National Park. The major trails followed 6 routes including Sambulsa-Geumobong(A), Yongjangsaji-Geumobong(B), Yongjanggol-Yiyoungjae-Gowibong(C), Cheonusa-Gowibong(D), Sangseojang-Forest road(E) and Tongiljeon-Forest road(F). The routes length of A was 2.2 km, 2.7 km of B, 3.4 km of C, 1.3 km of D, 2.0 km of E and 1.0 km of F. In the physical characteristics, A was the widest and F was the narrowest in the width and bared width of trail. In depth of erosion, B was the deepest and E was the shallowest. D was the steepest and E was the gentlest in the slope. In the results of analysing the types of deterioration, A were 13 types, 11 types of B, C and D, 10 types of E and 6 types of F. The times of appearance of deterioration types in A were 86 times, 75 times of B, 105 times of C, 48 times of D, 47 times of E and 13 times of F. In case of the impact rating class, trail erosion was II degree, I degree of trail expansion, root exposure, trail divergence and rock exposure.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.168-175
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• 2018

In order to investigate the effect of the chemical treatment of bamboo fiber on physical properties of polypropylene (PP)/bamboo fiber (BF) composites, silane coupling agents such as ${\gamma}$-aminopropyltriethoxysilane (APS), ${\gamma}$-glycidoxypropyl-trimethoxysilane (GPS) and ${\gamma}$-mercaptopropyltrimethoxysilane (MRPS) were applied to BF and alkaline treated BF. Morphological properties of the chemically treated BF were confirmed by optical microscope and SEM measurements, and chemical structure changes were confirmed by FT-IR and EDS. TGA results showed that the thermal stability of silane treated BF increased. Based on the analysis of a universal testing machine and an Izod impact test, the flexural and impact properties of PP/silane treated BF composites showed higher values than those of PP/BF composites. The enhancement of interfacial adhesion properties of the PP/BF composite was checked from SEM images of the fracture of specimens after the tensile test.

• PNF and Movement
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• v.18 no.1
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• pp.127-132
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• 2020

Purpose: This study aimed to investigate the impact of resistance on the muscle activities of the long and short heads of the biceps brachii, according to the elbow angle in supination, and the difference in muscle activity between the long and the short heads. Methods: This study was conducted with 22 men in their 20s who voluntarily agreed to participate. With the glenohumeral joint neutral in a position of supination, the elbow angle was randomly moved to 0°, 30°, 60°, and 90°. Using an 8-channel surface EMG while the participants held a 2-kg. dumbbell, the muscle activities of the long and the short heads of the biceps brachii were measured. The measured data were statistically processed using SPSS for Windows 12.0. For the activities of the short and the long heads according to the angle, a one-way ANOVA was conducted, and subsequently, to check the results of an analysis of the difference between groups, an LSD post-hoc test was conducted. An independent t-test was used to compare the activities of the long head and the short head according to the angles. Results: The analysis of the impact of the load of the dumbbell at each elbow angle on the muscle activities of the long and short heads of the biceps brachii revealed significant differences in both heads (p < 0.05). The result of the post-hoc analysis showed significant differences in both heads at angles between 0° and 30°, between 0° and 60°, and between 0° and 90°. Analysis of the impact of the load of the dumbbell in supination on the muscle activities of the long and short heads showed a significant difference at the angle between 0° and 30° (p < 0.05). Conclusion: The long head of the biceps brachii mainly acts in supination; however, in supination at elbow-bending angles of 60° and 90°, there was no difference in muscle activity between the short head and the long head.

• Journal of Sport and Applied Science
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• v.7 no.2
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• pp.1-12
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• 2023

Purpose: The purpose of this study was to investigate the possibility of modified swing to prevent shoulder injury by analyzing differences in the muscle activation patterns of upper limb by the swing method in wheelchair badminton players. Research design, data, and methodology: 10 wheelchair badminton players participated in the experiment as subjects and performed 10 high clears and 10 smashes in both traditional and modified swing methods toward a shuttlecock hung at the height of racket impact point. For each trial, activation patterns of biceps brachii, triceps brachii, anterior deltoid, and posterior deltoid were measured from the upper limb participating in the swing from which the duration, peak, and root mean square (RMS) of electromyography (EMG) activities from swing initiation to shuttle impact were calculated. The maximum swing velocity of the smash and the distance of the high clear were also measured with both methods to compare differences in the swing velocity and shuttle hit distance. Results: Differences in the EMG peak and RMS of the anterior deltoid by swing methods were shown to differ by the skill type, being higher in the traditional swing method than the modified during only the high clear. The EMG peak and RMS, and the duration of the posterior deltoid were higher and longer with the traditional swing method than the modified during both the smash and high clear. The intensities of the biceps brachii and triceps brachii activities measured during the smash and high clear were higher in the traditional swing method than the modified, and the biceps brachii and triceps activity durations during the high clear were shorter in the modified swing method than the traditional. The maximum swing velocity of the smash was faster with the traditional swing method than the modified, while the distance of the high clear did not differ significantly. Conclusions: These results suggest that the modified swing can be an effective performance method for preventing shoulder injuries without undue loss of impact power in wheelchair badminton players by reducing excessive loads imposed on the shoulder and allowing the optimal use of the elbow extension.

• Resources Recycling
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• v.33 no.1
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• pp.48-57
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• 2024

This study aimed to improve utilization of the Class C vinyl waste generated in rural areas based on a preliminary investigation on the use of eco-powder, generated through pyrolysis, as a raw material for plastic. The efficiency of pre-processing treatments in controlling ash content of the generated eco-powder and its effect on the basic properties of manufactured plastic were evaluated. The basic properties included ash content of the compressed eco-powder at different levels of ash content, impact strength, flexural strength, and tensile strength. The experimental results confirmed that pre-processing improved the separation efficiency of soil particles and vinyl waste through physical impact. The eco-powder with ash content of less than or equal to 26% was found to satisfy the target performance during impact strength, flexural strength, and tensile strength evaluation. Thus, it was confirmed that the Class C vinyl waste, having low utilization and recovery rates, could be effectively utilized as a plastic raw material after optimum thermal treatment and physical processing using the eco-powder.

• Journal of the Korean Society of Clothing and Textiles
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• v.48 no.1
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• pp.140-156
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• 2024

This study examined how the motivational language of instructors in senior fashion model classes affects learners' achievement goal orientation and interpersonal competence, as well as their intention to continue participating. The participants in this study were active seniors aged 50 and above, and the analysis was conducted using PLS-SEM and bootstrapping for mediation effects. It was found that autonomous motivation had a significant impact on task achievement goals and interpersonal competence, but not on ego achievement goals. On the other hand, controlled motivation only had a significant impact on ego achievement goals. Additionally, interpersonal competence had a significant impact on the intention to continue participating, and task achievement goals were found to mediate the relationship between autonomous motivation and interpersonal competence. This study aimed to promote understanding of the importance of instructors' motivational language in senior fashion model education and learners' psychology and to provide information that can help develop a fashion-related leisure activity curriculum. It also suggests efficient instructional directions for instructors in senior education, and it is expected to be utilized in the development of fashion-related leisure activity program curricula in the future.

• Journal of dental hygiene science
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• v.10 no.2
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• pp.109-116
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• 2010

Objective: The purpose of this study was oral health related quality of life among elderly population in some rural area, Korea. Methods: 546 participants (male 196, female 350) aged more than 65 years (mean $71.4{\pm}4.6\;years$) were surveyed cross-sectionally. All the subjects were examined short-form of Oral Health Impact Profile (OHIP-14) by face to face interview. Categorical responses of strata-adjusted Wilcoxon correlation and Kruskal-Willis test and multiple regression analysis after adjusting for socio-demographic variables were adapted for statistical analysis. Results: 1. As for sub-factors of the quality of living related to oral health, the drop in social ability was 4.61, the drop in mental ability 4.53, the drop in physical ability 3.99, mental inconvenience 3.98, social disadvantages 3.82, physical pains 3.77, and functional division 3.44, on the average. 2. As for the quality of living related to oral health, there were statistically significant differences in functional restrictions by gender, the educational level, and the presence of occupation, in physical pains by gender, the educational level, family members living together. mental inconvenience by gender, the educational level, the presence of occupation. and in the drop in physical ability by gender, the educational level, monthly incomes. There were statistically significant differences in the drop in physical ability by gender, the educational level. in the drop in social ability by the educational level, the presence of occupation, monthly income. and in social inconvenience by age, the presence of occupation, monthly income. 3. There were statistically significant differences in the general quality of living related to oral health by gender, the educational level, the presence of occupation.