• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.2
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• pp.380-393
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• 2003

In order to evaluate the effect of Chekambohyulansin-tang (CST) which was a traditional poly-herbal formula has been used for treatment of obesity in Korea, on the obesity in ovariectomized rats, the changes of body weight, peri-kidney, abdominal and perineal subcutaneous fat weight and their histological changes were measured with the detection of number and/or size of adipocytes after an oral administration of CBT extracts (125, 250 and 500 mg/kg, respectively). CBT significantly attenuated elevations in the body weight, the absolute and relative weight of peri-kidney, abdominal and perineal fat tissues and decrease the severe hypertrophy, the number of adipocytes, and the diameter of adipocytes of peri-kidney, abdominal and perineal fat tissues in ovariectomized rats in a dose dependent manner. These results provide a story evidence that CBT can playa role in the treatment of obesity induced by ovariectomy. Determination of the specific mechanisms involred toxicological dosage of CBT on obesity will require addition study.

• Steel and Composite Structures
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• v.28 no.1
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• pp.13-24
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• 2018

A size-dependent novel hyperbolic shear deformation theory of simply supported functionally graded beams is presented in the frame work of the non-local strain gradient theory, in which the stress accounts for only the nonlocal strain gradients stress field. The thickness stretching effect (${\varepsilon}_z{\neq}0$) is also considered here. Elastic coefficients and length scale parameter are assumed to vary in the thickness direction of functionally graded beams according to power-law form. The governing equations are derived using the Hamilton principle. The closed-form solutions for exact critical buckling loads of nonlocal strain gradient functionally graded beams are obtained using Navier's method. The derived results are compared with those of strain gradient theory.

• Structural Engineering and Mechanics
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• v.74 no.2
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• pp.175-187
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• 2020

The theories having been developed thus far account for higher-order variation of transverse shear strain through the depth of the beam and satisfy the stress-free boundary conditions on the top and bottom surfaces of the beam. A shear correction factor, therefore, is not required. In this paper, the effect of surface on the axial buckling and free vibration of nanobeams is studied using various refined higher-order shear deformation beam theories. Furthermore, these theories have strong similarities with Euler-Bernoulli beam theory in aspects such as equations of motion, boundary conditions, and expressions of the resultant stress. The equations of motion and boundary conditions were derived from Hamilton's principle. The resultant system of ordinary differential equations was solved analytically. The effects of the nanobeam length-to-thickness ratio, thickness, and modes on the buckling and free vibration of the nanobeams were also investigated. Finally, it was found that the buckling and free vibration behavior of a nanobeam is size-dependent and that surface effects and surface energy produce significant effects by increasing the ratio of surface area to bulk at nano-scale. The results indicated that surface effects influence the buckling and free vibration performance of nanobeams and that increasing the length-to-thickness increases the buckling and free vibration in various higher-order shear deformation beam theories. This study can assist in measuring the mechanical properties of nanobeams accurately and designing nanobeam-based devices and systems.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.93-93
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• 2013

To make the rationale design of interface between cell and artificial surface, many studies have been controlled influencing cue which can typically be divided into two central categories: chemical cues based on modification surface chemical properties containing attractive/repulsive molecules, and physical cues that may include applied tension/stress, electrical polarization, magnetic field, and topography. Recently, researches have been focused on physical cue, especially topography. The surface topography may influence cellular responses for example, cell adhesion, cell morphology and gene expression. However, there were few systematic studies about these nanotopographical effects on neuronal developments in a feature size-dependent manner. Herein, we report a nanoscale-resolved study of nanotopographical effects on cellular adhesion and growth. In this study, we use substrates with packed glass beads by rubbing method for generating highly periodic nanotopographies with various sizes. We found that acceleration of neuritogenesis appeared only on the beads larger than 200 nm in diameter, and observed that filopodial thickness was comparable with this scale. This study is expected to be essential to elucidate the nanotopographical effect on cellular adhesion and growth.

• Korean Journal of Materials Research
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• v.29 no.3
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• pp.189-195
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• 2019

The effect of C, Mn, and Al additions on the tensile and Charpy impact properties of austenitic high-manganese steels for cryogenic applications is investigated in terms of the deformation mechanism dependent on stacking fault energy and austenite stability. The addition of the alloying elements usually increases the stacking fault energy, which is calculated using a modified thermodynamic model. Although the yield strength of austenitic high-manganese steels is increased by the addition of the alloying elements, the tensile strength is significantly affected by the deformation mechanism associated with stacking fault energy because of grain size refinement caused by deformation twinning and mobile dislocations generated during deformation-induced martensite transformation. None of the austenitic high-manganese steels exhibit clear ductile-brittle transition behavior, but their absorbed energy gradually decreases with lowering test temperature, regardless of the alloying elements. However, the combined addition of Mn and Al to the austenitic high-manganese steels suppresses the decrease in absorbed energy with a decreasing temperature by enhancing austenite stability.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.7
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• pp.195-201
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• 2021

This study aims to assess the impact of ownership structure of commercial banks on bank credit risk in Vietnam. The authors used the unbalanced table data of 28 commercial banks in the period from 2004 to 2020 with 439 observations. The ratio of loan loss provisioning to loans (CR) is selected as a dependent variable representing credit risk at commercial banks. The regression methods used include: least squares method (OLS), fixed-effect model (FEM), random-effect model (REM) and general least squares method (GLS). The results reveal that, with interaction variable between the ratio of equity to total assets and foreign ownership, the national GDP annual growth rate is negatively associated with credit risk. With the ratio of equity to total assets, the interaction variable between equity and state ownership, and bank size have a significant positive impact on credit risk. In addition, inflation has negligible impact on the credit risk of commercial banks in Vietnam over the research period. The findings of this study suggest that, if foreign-owned banks increase equity capital, there will be a stronger impact on reducing credit risk than other banks. On the other hand, when state-owned commercial banks in Vietnam increase equity, they will have higher credit risk.

• East Asian Economic Review
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• v.27 no.3
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• pp.179-211
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• 2023

This paper investigates the relationship between the spread of COVID-19 and time preference. In contrast to previous studies that compared time preferences before and during the pandemic, this study estimates time preferences during the COVID-19 period using eight surveys conducted over two years. Additionally, a regression analysis was conducted on the number of new COVID-19 cases and the time elapsed since the outbreak, with estimated time preference as the dependent variable. Despite a small sample size, statistically significant results were obtained, showing that as the number of new cases increased, time preference also increased. However, this effect diminished over time and disappeared by the end of 2021 in Japan. This may be due to the public's growing familiarity with the risks of COVID-19 and the availability of vaccines and treatments. Despite a significant increase in new cases in 2022, time preference was lower than immediately after the outbreak, and this was reflected in private investments. Immediately after the outbreak of COVID-19, private investments decreased by 12% compared to the previous year, but the investments are returning in 2022 despite the surge in the number of cases. The trend of time preference explains the trend of Japanese private investments very well.

• Steel and Composite Structures
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• v.52 no.5
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• pp.501-513
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• 2024

Two-directional functionally graded materials (2D-FGMs) show extraordinary physical properties which makes them ideal candidates for designing smart micro-switches. Pull-in instability is one of the most critical challenges in the design of electrostatically-actuated microswitches. The present research aims to bridge the gap in the static pull-in instability analysis of microswitches composed of 2D-FGM. Euler-Bernoulli beam theory with geometrical nonlinearity effect (i.e. von-Karman nonlinearity) in conjunction with the modified couple stress theory (MCST) are employed for mathematical formulation. The micro-switch is subjected to electrostatic actuation with fringing field effect and Casimir force. Hamilton's principle is utilized to derive the governing equations of the system and corresponding boundary conditions. Due to the extreme nonlinear coupling of the governing equations and boundary conditions as well as the existence of terms with variable coefficients, it was difficult to solve the obtained equations analytically. Therefore, differential quadrature method (DQM) is hired to discretize the obtained nonlinear coupled equations and non-classical boundary conditions. The result is a system of nonlinear coupled algebraic equations, which are solved via Newton-Raphson method. A parametric study is then implemented for clamped-clamped and cantilever switches to explore the static pull-in response of the system. The influences of the FG indexes in two directions, length scale parameter, and initial gap are discussed in detail.

• Safety and Health at Work
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• v.15 no.3
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• pp.310-316
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• 2024

Background: The wood-processing industry has historically exhibited high rates of occupational hazards resulting in illness and injury. One of the major causes of high injury rates is small firm size, as resource constraints generally preclude hiring safety officers. This study examined the effect of a safety leadership training program that included coaching for managers on workers' safety behaviors and safety climate in three wood-processing companies. Methods: One or two managers at each site participated in this study. The manager training consisted of safety leadership education, safety observation, positive or corrective feedback on workers' behaviors, goal setting, and low-cost rewards for meeting goals. The dependent variable was the percentage of safe employee behaviors recorded on a critical behavior checklist developed for this study. Safety climate was measured before and after the intervention. An AB multiple baseline design across settings was adopted. After the baseline (A), the training program (B) was introduced to each site at different points in time. Results: After the introduction of safety leadership training, the mean rate of safety compliance increased by 15.3%, from 80.38% to 95.68%, and safety climate scores increased significantly from an average of 3.2 to 3.47. Conclusion: These results suggest that safety leadership coaching can be effective in improving safety management in small sawmilling sites. Implications, limitations, and possible future research directions are discussed.

• Journal of the Korea Convergence Society
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• v.11 no.5
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• pp.87-96
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• 2020

The purpose of this study is to evaluate the convergence effectiveness of treadmill training in patients with chronic stroke through a meta-analysis. After searching the literature based on the patients, intervention, comparison, outcome criteria, and study desigan, a total of 22 studies related to "stroke" and "treadmill" were eligible for inclusion. Effect size was calculated using the comprehensive meta-analysis program for the meta-analysis. Based on the forest plot results, the overall effect size of treadmill training was 0.661 (95% confidence interval: 0.456-0.865), which was statistically significant with a medium effect size (p < 0.05). The effects of treadmill training on patients with stroke were separated by dependent variables of interest-plantar pressure (1.147), lower limb muscle function (0.875), and balance (0.664). The effect sizes were evaluated for the subdomains of timed up and go test (0.553), Berg Balance Scale (0.760), and static balance index (0.654) for balance. Therefore, treadmill training can be expected to have a positive impact on improving the quality of life of patients with chronic stroke. This meta-analysis of treadmill training may the lead to an industry paradigm shift toward healthcare convergence of information, communication, and medical technology.