• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.149-165
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• 2001

This study was performed to define the cytotoxicity and the anti-inflammatory action of Pulsatilla koreana extracts. To analyze cytotoxic effects, gingival and periodontal ligament fibroblasts were used, and anti-inflammatory actions related to reduction of $IL-1{\beta}$ and $PGE_2$ production were performed in vitro, for the suggestion of efficacy and safety on periodontal therapeutic use of Pulsatilla koreana extracts. We extracted ethylacetate and butylalcohol from well-dried and ground Pulsatilla koreana throughout multiple processing, then used different concentration solution(0.1 %, 0.2 %, 0.4 %, 0.01 %, 0.02 %, 0.04 %, 1 %, 2 %) of ethylacetate and butylalcohol extracts to examine eytotoxic effects and anti-inflammatory actions Cytotoxic effects were examined by ELISA reader using MTT(Methyl Thiazol-2-YL-2, 5-diphenyl Tetrazolium bromide)solution following culture of human gingival and periodontal ligament fibroblasts. Synthesis of $IL-1{\beta}$was examined by $IL-1{\beta}$ enzyme-immunoassay(EIA)system after separation and culture of monocyte, and $PGE_2$ was examined by $PGE_2EIA$ system after culture of gingival fibroblasts. The results were as follows: 1. In the MTT test of gingival fibroblasts, the change of optical density was decreased significantly at 2 % of butylalcohol extracts and 0.04 %, 0.1 %, 0.2 %, 0.4 %, 1 %, 2 % of ethylacetate extracts.(p<0.05) 2. In the MTT test of periodontal ligament cells, the change of optical density were not differ significantly. but butylalcohol and ethylacetate extracts except from butylalcohol 0.01 % showed high cell cytotoxity. 3. Both ethylacetate and butylalcohol extracts from Pulsatilla koreana inhibited the synthesis of $IL-1{\beta}$and inhibition effect of ethylacetate extracts were higher than butylalcohol extracts. 4. Both ethylacetate and butylalcohol extracts from Pulsatilla koreana inhibited the synthesis of $PGE_2$, and ethylacetate extracts were higher than butylalcohol extracts. In conclusion, ethylacetate and butylalcohol extracts from Pulsatilla koreana showed little cell cytotoxity for gingival and periodontal ligament fibroblasts, and the inhibition of $IL-1{\beta}$ and $PGE_2$ sysnthesis, therefore it is considered that these extracts can be developed as the therapeutics of the periodontal disease.

• Journal of the Korean Geotechnical Society
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• v.27 no.5
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• pp.85-92
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• 2011

The dynamic behavior of piles becomes very complex due to soil-pile dynamic interaction, soil non-linearity, resonance phenomena of soil-pile system and so on. Therefore, the proper numerical simulation of the pile behavior needs much effort and calculation time. In this research, a new modeling method, which can be applied to the conventional finite difference analysis program FLAC 3D, was developed to reduce the calculation time. The soil domain in this method is divided into a near-field region and a far-field region, which is not influenced by the soil-pile dynamic interaction. Then, the ground motion of the far-field is applied to the boundaries of the near-field instead of modeling the far-field region as finite meshes. In addition, the soil non-linearity behavior is modeled by using the hysteretic damping model, which determines the soil tangent modulus as a function of shear strain and the interface element was applied to simulate the separation and slip between the soil and pile. The proposed method reduced the calculation time by as much as one third compared with a usual modeling method and maintained the accuracy of the calculated results. The calculated results by the proposed method showed a good agreement with the prototype pile behavior, which was obtained by applying a similitude law to the 1-g shaking table test results.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.1
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• pp.55-61
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• 2023

This study aims to develop CLSM fill material for emergency restoration using landfill coal ash. As a result of examining physical properties such as particle size distribution and fines content of landfill coal ash, bottom ash, fly ash, and general soil were mixed, and SP was found to have a density of 2.03 and a residual particle pass rate of 7.8 %. CLSM materials that secure fluidity in unit quantities without using chemical admixtures such as glidants and water reducing agents have a high risk of material separation due to bleeding. As a result of this experiment, it was found that the bleeding ratio did not satisfy the standard in the case of the specimen with a large amount of fly ash and a lot of addition of mixing water. As a result of the compressive strength test, the strength development of 0.5 MPa or more for 4 hours was found to be satisfactory for the specimens using hemihydrate gypsum with a unit binder amount of 200 or more, and the remaining gypsum showed poor strength development. Although it is judged that landfill coal ash can be used as a CLSM material, it is necessary to identify and apply the physical and chemical characteristics of coal ash buried in the ash treatment plant of each power generation company.

• Journal of the Korea Institute of Building Construction
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• v.23 no.3
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• pp.295-303
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• 2023

South Korea has recently witnessed an increasing number of seismic events, leading to a surge in studies focusing on seismic earth pressures, as well as the attributes of geological layers and ground where foundations are established. Consequently, earthquake-resistant design has become imperative to ensure the safety of subterranean structures. The slurry wall method, due to its superior wall rigidity, excellent water resistance, and minimal noise and vibration, is often employed in constructing high-rise buildings in urban areas. However, given the separation between panels that constitute the wall, slurry walls possess limited resistance to seismic loads in the longitudinal direction. As a solution, several studies have probed into the possibility of interconnecting slurry wall panels to augment their seismic performance. In this research, we developed and evaluated a method for linking slurry wall panels using mechanical joints, including concrete-confined steel pipes and headed bars, through mock-up tests. We also assessed the constructability of the suggested method and compared it with other analogous methods. Any challenges identified during the mock-up test were discussed to guide future research in resolving them. The results of this study aid in enhancing the seismic performance of slurry walls through the development of an interconnected panel method. Further research can build on these findings to address the identified issues and improve the efficacy and reliability of the proposed method.