• Smart Structures and Systems
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• v.26 no.4
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• pp.481-493
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• 2020

The negative stiffness spring and inerter are both characterized by the negative stiffness effect in the force-displacement relationship, potentially yielding an amplifying mechanism for dashpot deformation by being incorporated with a series tuning spring. However, resisting forces of the two mechanical elements are dominant in different frequency domains, thus leading to necessary complementarity in terms of vibration control and the amplifying benefit. Inspired by this, this study proposes a Negative Stiffness Inerter System (NSIS) as an earthquake protection system and developed analytical design formulae by fully utilizing its advantageous features. The NSIS is composed of a sub-configuration of a negative stiffness spring and an inerter in parallel, connected to a tuning spring in series. First, closed-form displacement responses are derived for the NSIS structure, and a stability analysis is conducted to limit the feasible domains of NSIS parameters. Then, the dual advantageous features of displacement reduction and the dashpot deformation amplification effect are revealed and clarified in a parametric analysis, stimulating the establishment of a displacement-based optimal design framework, correspondingly yielding the design formulae in analytical form. Finally, a series of examples are illustrated to validate the derived formulae. In this study, it is confirmed that the synergistic incorporation of the negative stiffness spring and the inerter has significant energy dissipation efficiency in a wide frequency band and an enhanced control effect in terms of the displacement and shear force responses. The developed displacement-based design strategy is suitable to utilize the dual benefits of the NSIS, which can be accurately implemented by the analytical design formulae to satisfy the target vibration control with increased energy dissipation efficiency.

• Korean Journal of Microbiology
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• v.21 no.3
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• pp.115-126
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• 1983

The results that the effect of 6 detergents on the structural changes and biochemical composition of bacterial membrane of Escherichia coli and Bacillus cereus are as follows ; 1. Population growth of the bacteria was increased in case of the treatment with palmitoyl carnitine and sodium deoxy cholate but was increased in case of the treatment with palmitoyl carnitine and sodium deoxy cholate but was decreased by sodium dodecyl sulfate and palmitoyl choline, in E.coli and was decreased by palmitoyl carnitine and palmitoyl choline at the low concentration, in B. cereus. 2. The electron micrograph showed that cell wall lysis or cell collapse were observed in the treatment of sodium dodecyl sulfate and palmitoyl choline, and also cell wall was condensed by triton X-100 and sodium deoxy cholate, in E.coli. And in B. cereus, endospore formation of the bacteria was stimulated by palmitoyl choline, and cell lysis or structural changes of the membrane were observed in the treatment of sodium dodecyl sulfate, sodium cholate, and triton X-100, respectively. 3. As to the effect of detergent on the biochemical composition of biomembrane, the content of carnitine, in E.coli, and B.cereus, the content of structural protein and phospholipid were decreased by treatment of sodium dodecyl sulfate and structural protein was denatured by palmitoyl choline. 4. The profile of membrane protein revealed that the bacterial membrane were composed of various proteins. By dint of this result, some of membrane proteins were solubilized or changed to small molecules by the treatment of sodium dodecyl sulfate and palmitoyl choline, in E.coli and membrane protein of the biomembrane by treatment of sodium dodecyl sulfate, sodium deoxy cholate, palmitoyl choline, and palmitoyl carnitine were confirmed to be different profile as compared with those of the control, in B. cereus. Therefore, it is suggested that sodium dfodecyl sulfate and palmitoyl choline soulbilized biomembranes or inhibited membrane transport and that palmitoyl carnitine and sodium deoxy cholate were used as an energy source or stimulating the membrane transport, in E.coli. And, it is suggested that all of detergents were inhibited biomembrane synthesis, expet saponin, in B.cereus.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2564-2572
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• 2015

Entrepreneurial education for university students furnishes necessary knowledges and fosters competences of potential entrepreneurs and help them change their attitudes toward start-up of a new business. This study examines how entrepreneurial education affects promoting entrepreneurship and stimulating entrepreneurial motivation of university students. Testing mediating of entrepreneurship between entrepreneurial education and motivation is another aim of this study. Regression analysis was used to examine each hypothesis of the study. Following refers to summary of the findings of the study; at first, entrepreneurial education affects entrepreneurial motivation of university students positively. Secondly, entrepreneurial education influences promoting entrepreneurship of students. Thirdly, entrepreneurship has a positive effect on entrepreneurial motivation significantly. Lastly, entrepreneurship plays a mediating role between entrepreneurial education and motivation of students. Both theoretical and practical implication were provided based on the findings of the study.

• Advances in Traditional Medicine
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• v.5 no.3
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• pp.188-194
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• 2005

The Angelicae dahuricae radix (ADR) has been used a traditional medicine to treat acne, erythema, headache, toothache, sinusitis, colds, and flu in Korea, Japan and China. Here, we report the effect of ADR on compound 48/80-induced ear-swelling and the phorbol myristate acetate (PMA) plus calcium ionophore A23187-induced inflammatory cytokine secretion in the human mast cell line, HMC-1. ADR dose-dependently inhibited the ear-swelling response induced by intradermal injection of compound 48/80, In vitro model, PMA plus A23187 significantly increased interleukin $(IL)-1{\beta}$, IL-8, granulocyte macrophage colony stimulating factor (GM-CSF), and tumor necrosis factor $(TNF)-{\alpha}$ secretion compared with media control. We also show that the increased cytokines $IL-1{\beta}$, IL-8, GM-CSF, and $TNF-{\alpha}$ level was significantly inhibited by treatment of ADR. In addition, ADR partially blocked PMA plus A23187-induced extracelluar signal-regulated kinases phosphorylation. These results suggest that ADR might explain its beneficial effect in the treatment of mast cell-mediated inflammatory diseases.

• Journal of Korean Medicine Rehabilitation
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• v.30 no.2
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• pp.19-35
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• 2020

Objectives The aim of this study is to evaluate the fracture healing effect of Jinmu-tang (JM) on femur fractured rats. Methods Rats were randomly divided into 5 groups (normal, control, positive control, JM extract with low concentration and JM extract with high concentration). All group except normal group went through both femur fracture. Normal and control group received no treatment at all. Positive control group were medicated with tramadol (20 mg/kg) once a day for 14 days. Experimental group was orally medicated with JM extract (10 mg/kg for low concentration, 50 mg/kg for high concentration) once a day for 14 days. In order to investigate fracture healing process, plasma and serum were obtained. Also, micro-computed tomography was conducted to see the frature site visually. Immunohistochemistry for transforming growth factor-β1, Ki67, alkaline phosphatase, runt-related transcription factor 2, receptor activator of nuclear factor kappa-β, tartrate resistant acid phosphatase was conducted to observe bone healing progress after 14 days since fracture occured. Aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen and creatinine levels were measured in plasma, for hepatotoxicity and nephrotoxicity of JM extract. Osteocalcin was measured to observe activity of osteoblast. Results Through Micro-CT, more fracture healing was observed on both experimental group than control and positive control group. Through Hematoxylin & Eosin and safranin O staining showed bone cell proliferation and bone formation in the experimental group. RANK was significantly increased in the experimental groups. JM with high concentration showed statistically significant of TGF-β and Osteocalcin. NO, TRAP and ALP were not significantly changed. Liver toxicity was not significantly observed. Creatinine significantly increased in both experimental groups after 28 days. Conclusions As described above, JM extract showed anti-inflammatory effect, promoted fracture healing by stimulating the bone regeneration factor, and showed little hepatotoxicity and nephrotoxicity. In conclusion, JM extract can promote fracture healing and it can be used clinically to patients with fracture.

• Journal of Korean Medicine Rehabilitation
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• v.30 no.4
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• pp.17-30
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• 2020

Objectives The purpose of this study is to evaluate the healing effect of Yukmijihwang-tang (YM) on femur fractured mice. Methods Mice were randomly divided into 6 groups: normal, control, positive control, YM with low, medium, high dosage each. All groups were prepared with femur fracture and treated diffrently. In order to measure bone regeneration effects, we analysed the levels of cyclooxygenase-2 (COX2), bone morphogenetic protein-2 (BMP2), collagen type II alpha 1 chain (Col2a1), Sox9, runt-related transcription factor 2 (Runx2), and osterix genes expressed in bone. For morphological analysis, muscles were removed and femur was observed with naked eye. Results COX2 gene expression in bone marrow significantly decreased. BMP2 gene expression significantly increased. Col2a1 gene expression significantly increased. Sox9 gene expression increased as well. Runx2 gene expression in bone marrow increased, but there was no statistical significance. Osterix gene expression significantly increased. Union of the fracture site progressed more in YM group compared to the control group. The fracture union score was significantly decreased in YM group compared to the control group. Conclusions YM showed anti-inflammatory effect, promoted bone regeneration by stimulating the bone regeneration factor. In conclusion, YM can help fracture healing and it well be applied clinically to patients with fracture.

• Journal of Korea Game Society
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• v.11 no.6
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• pp.3-11
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• 2011

The sound of digital media would be able to perform communication by stimulating body's senses. Because the sound stimuli could arouse a person into the physiological excitement and sensitivity, which appear as the changes of heartbeat, blood pressure, brain waves(EEG) signals. In this paper, we would like to examine whether the game music mixed with relaxing white noises has an effect to relax game player or not through the EEG changes of game players. For the experiment, we divided game players into group A that plays game while hearing game music mixed with white noises, and group B that plays game while hearing game music not mixed. And we measured the EEG changes of the prefrontal lobe between two groups. The result shows that the game music mixed with white noises has an relaxing effect for the left brain, but fall short of the expectations for the right brain. It would be a basic research which will contribute to the development of serious games for psychotherapy using relaxing white noises.

• Journal of Life Science
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• v.17 no.10
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• pp.1354-1360
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• 2007

Theaflavins (TF) and thearubigins (TR) are constituents of tea pigments which are polyphenols derived from Korean fermentation tea. After TF, TR and [(-) epigallocatechin-3-gallate](EGCG) have been applied to macrophage cell line (RAW264.7) nitric oxide (NO) synthesis and cytokines production were estimated. Cytokines production by enzyme linked immune-sorbent assay (ELISA) determined. NO production was increased by about 1.5-folds at the dose of $80\;{\mu}g/ml$ compared to control and lipopolysaccharide (LPS) stimulation when TF, TR and EGCG were applied to a RAW264.7 cell. Interleukin-6 (IL-6), Tumor necrosis factor ($TNF-{\alpha}$) and granulocyte-macrophage colony stimulating factor (GM-CSF) increased depended on concentrations of TF, TR and EGCG. The production of tumor necrosis $factor-{\alpha}$ increased highly in TR, TF and EGCG group with LPS. These results suggest that TF, TR and EGCG have immune-enhancement effect through the cytokine production. TF, TR and EGCG inhibited cancer cell viability, the anticancer effect of these polyphenols may explain the anti-tumor promotion action and antioxidant activity of these tea constituents.

• Molecules and Cells
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• v.40 no.8
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• pp.550-557
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• 2017

The periodontal ligament (PDL) is the connective tissue between tooth root and alveolar bone containing mesenchymal stem cells (MSC). It has been suggested that human periodontal ligament stem cells (hPDLSCs) differentiate into osteo/cementoblast and ligament progenitor cells. The periodontitis is a representative oral disease where the PDL tissue is collapsed, and regeneration of this tissue is important in periodontitis therapy. Fibroblast growth factor-2 (FGF-2) stimulates proliferation and differentiation of fibroblastic MSCs into various cell lineages. We evaluated the dose efficacy of FGF-2 for cytodifferentiation of hPDLSCs into ligament progenitor. The fibrous morphology was highly stimulated even at low FGF-2 concentrations, and the expression of teno/ligamentogenic markers, scleraxis and tenomodulin in hPDLSCs increased in a dose dependent manner of FGF-2. In contrast, expression of the osteo/cementogenic markers decreased, suggesting that FGF-2 might induce and maintain the ligamentogenic potential of hPDLSCs. Although the stimulation of tenocytic maturation by $TGF-{\beta}1$ was diminished by FGF-2, the inhibition of the expression of early ligamentogenic marker by $TGF-{\beta}1$ was redeemed by FGF-2 treatment. The stimulating effect of BMPs on osteo/cementogenesis was apparently suppressed by FGF-2. These results indicate that FGF-2 predominantly differentiates the hPDLSCs into teno/ligamentogenesis, and has an antagonistic effect on the hard tissue differentiation induced by BMP-2 and BMP-4.

• Archives of Plastic Surgery
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• v.34 no.2
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• pp.156-162
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• 2007

Purpose: In the previous in vitro studies the bone marrow stromal cells(BSCs) have shown the superior effect for wound healing activity than fibroblasts, which includes cell proliferation, type I collagen synthesis, and the production of bFGF, VEGF and TGF-${\beta}$ in chronic wound healing. The aim of this study is to compare the effects of BSCs and fibroblasts on wound healing activity in vivo, especially on collagen synthesis. Methods: The fibroblasts and BSCs were harvested from patients and cultured. The cultured cells were infiltrated into the pores of polyethylene discs. These discs were divided into three groups according to the mixed cells. In groups I, II and III the discs were loaded with no cells, fibroblasts and BSCs, respectively. Twelve discs per group(total 36 discs) were made for this study. After creating 6 pockets in the back of each rats, each discs was implanted into each pockets. At three time intervals from 1 to 3 weeks, the implanted discs were harvested for the histological and quantitative analysis. The amount of collagen produced was evaluated using ELISA. Statistical comparisons were made using the Mann-Whitney U-test. Results: There was great difference in the collagen synthesis among the three groups by the 1st and 2nd weeks. The BSC group showed highest collagen level, followed by fibroblast group and no cell group(p<0.05). The 3rd week specimens also showed greater collagen amount in BSC and fibroblast groups compared to those of no cell group(p<0.05). However, there was little difference between BSC and fibroblast groups. Conclusion: This result demonstrates that BSC has superior effect on stimulating wound healing than fibroblast, which is currently used for wound healing.