• Transactions of the Korean Society of Mechanical Engineers A
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• 제28권7호
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• pp.1014-1020
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• 2004

The present work complies the elastic stress concentration factor for a pipe with local wall thinning, based on detailed three-dimensional elastic FE analysis. To cover practically interesting cases, a wide range of pipe and defect geometries are considered, and both internal pressure and global bending are considered. Resulting values of stress concentration factors are tabulated for practical use, and the effect of relevant parameters such as pipe and defect geometries on stress concentration factors are discussed. The present results would provide valuable information to estimate fatigue damage of the pipe with local wall thinning under high cycle fatigue.

• The Korean Journal of Franchise Management
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• 제12권2호
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• pp.35-49
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• 2021

Purpose: The major objective of this study is to develop a model for the impact of franchisors' Gapjil (verbal·nonverbal Gapjil, abusing bargaining position, refusing transaction, false or exaggerated information, restrictive practices, unfair damage compensation) on franchisee's recontract intention. We also examine the mediating role of economic satisfaction and social satisfaction in the relationship between franchisors' Gapjil and franchisee's contract intention. Research design, data, and methodology: Data were collected from franchisee owners located nationwide in Korea. Out of 256 questionaires distributed, a total of 256 questionnaires were returned. After excluding 10 invalid respondent questionnaires, we coded and analyzed 246 valid questionnaires (effective response rate of 96.09%) using frequency, confirmatory factor analysis, correlations analysis, and structural equation modeling with SPSS 22.O and SmartPLS 3.0. Results: The findings of this study are summarized as follows: First, among the Gapjil of the franchisors, restrictive practices and unfair damage compensation had negative effects on economic and social satisfaction, but verbal and nonverbal Gapjil for economic and social satisfaction was not significant. Second, abusing bargaining positions and false or exaggerated information had negative effects on social satisfaction, but for economic satisfaction, found to be insignificant. Third, economic and social satisfaction had positive effects on the franchisee's recontract intention to the franchisor. Conclusion: The following implications of this study are as follows. First, the construct of Gapjil that occurs between the franchisors and the franchisees was first presented, and the franchisors' Gapjil is divided into interpersonal Gapjil and structural Gapjil. Second, the Gapjil of the franchisors can be an important predictor variable in maintaining and developing a long-term relationship between the franchisors and the franchisees. Third, solving conflict due to the Gapjil problem between franchisors and franchisees can be an important factor for franchisors and franchisees to co-survive and thrive in Korean franchise system. Fourth, this study suggest that managing the Gapjil of the franchisors was a important antecedent factor in maintaining long-term relationship between the franchisors and the franchisees. Therefore, this study will help franchisors formulate effective symbiotic marketing strategies to satisfy relationships with franchisees and consequently enhance long-term orientation.

• Herbal Formula Science
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• 제29권3호
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• pp.127-145
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• 2021

Objectives : The purpose of this study was to evaluate the effects of Daeganghwal-tang on knee cartilage in monosodium iodoacetate(MIA)-induced osteoarthritis rats. Methods : Forty SD rats were randomly divided into five groups(n=8/group): normal group was SD rats group injected with normal saline at left knee joint and administrated orally distilled water, control group was MIA-induced osteoarthritis SD rats group administrated orally distilled water, Indomethacin group was MIA-induced osteoarthritis SD rats group administrated orally indomethacin 2 mg/kg, DGHT(L) group was MIA-induced osteoarthritis SD rats group administrated orally 1280 mg/kg of Daeganghwal-tang, and DGHT(H) group was MIA-induced osteoarthritis SD rats group administrated orally 2560 mg/kg of Daeganghwal-tang. After orally administration of drugs for 4 weeks, gross appearance and histological analysis were used to evaluate the degree of knee cartilage damage. In addition, pro-inflammatory cytokines, bone degrade factor and bone defence factors were analyzed to investigate the anti-inflammatory and cartilage protection effects of Daeganghwal-tang. Also, hematological test, biochemical test, and liver and kidney tissue were analyzed to determine the safety of Daeganghwal-tang. Results : Daeganghwal-tang inhibited the damage of the knee cartilage, and significantly prevented the reduction in cartilage thickness. In addition, the pro-inflammatory cytokines and the bone degrade factor significantly decreased, and the bone defence factors significantly increased. In the safety assessment of Daeganghwal-tang, there were no significant differences among the experimental groups and no abnormal findings were observed. Conclusions : Daeganghwal-tang has anti-inflammatory effect, inhibits cartilage damage, and protects cartilage in MIA-induced osteoarthritis rats.

• Journal of Microbiology and Biotechnology
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• 제12권4호
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• pp.598-602
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• 2002

Damage to cells exposed to radiation is primarily attributed to direct effects on the structure of cellular DNA. Radiation-induced damage of pBluescript SK plasmid DNA and Escherichia coli $DH5\alpha$ were examined in the presence of various branched oligosaccharides, polysaccharides, and/or 8-MOP (8-methoxypsoralen). Branched oligosaccharides efficiently protected DNA and cells exposed to ultrasoft X-ray and UV irradiation. In the presence of 0.2% (w/v) branched oligosaccharides and polysaccharides, DNA can be protected from damage due to W and ultrasoft X-ray by a factor of 1.3-2.1 fo1d and 3.2-8.3 fold, respectively. The protective effect of cells exposed to UV or ultrasoft X-ray was also observed by branched oligosaccharides. The combination of MOP, a photoreagent, with carbohydrates increased the protective effects for DNA and cells, compared with that of a single use of MOP or carbohydrate alone.

• The Journal of Korean Medicine
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• 제21권2호
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• pp.68-78
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• 2000

Objective : This research was performed to investigate protective effects of Sophora subprostrata, against ischemic brain damage after a middle cerebral artery(MCA) occlusion. The effect was estimated using histological test, neurobehavioural test, and biochemical test. Methods : Rats(Sprague-Dawley) were divided into four groups: Sham operated group, MCA occluded group, Sophora subprostrata administrated group after MCA occlusion, and Normal group. The MCA was occluded by intraluminal method. Sophora subprostrata was administrated orally twice(l and 4 hours) after middle cerebral artery occlusion. The neurobeavioural test was performed at 3 hours, 6 hours, 9 hours and 24 hours after the surgery by posture reflex test and swimming behavioural test. All groups were sacrificed at 24 hours after the surgery. The brain tissue was stained with 2% triphenyl tetrazolium chioride(TTC) or 1 % cresyl violet solution, to examine effect of Sophora subprostrata on ischemic brain tissue. The blood samples were obtained from the heart of rats. Tumor necrosis factor-a level was measured from sera using Enzyme-Linked Immunoabsorbent Assay(ELISA). Results : The results showed that (1) Sophora subprostrata reduced infarct size and total infarct volume by 54.8% compared to the control group, (2) that neuronal death, which was shown by decrease in cell number and size, was attenuated significantly in the boundary area of the infarction, (3) that serum $TNF-{\alpha}$ㆍlevel was reduced significantly, and finally, there was significant recovery of motor deficit at 3 hours after MCA occluded by Swimming behavioural test. Conclusions :In conclusion, Sophora subprostrata has protective effects against ischemic brain damage at the early stage of ischemia.

• Geomechanics and Engineering
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• 제36권2호
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• pp.167-181
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• 2024

The soil-structure relative stiffness is a key factor affecting the seismic response of underground structures. It is of great significance to study the soil-structure relative stiffness for the soil-structure interaction and the seismic disaster reduction of subway stations. In this paper, the dynamic shear modulus ratio and damping ratio of an inhomogeneous soft soil site under different buried depths which were obtained by a one-dimensional equivalent linearization site response analysis were used as the input parameters in a 2D finite element model. A visco-elasto-plastic constitutive model based on the Mohr-Coulomb shear failure criterion combined with stiffness degradation was used to describe the plastic behavior of soil. The damage plasticity model was used to simulate the plastic behavior of concrete. The horizontal and vertical relative stiffness ratios of soil and structure were defined to study the influence of relative stiffness on the seismic response of subway stations in inhomogeneous soft soil. It is found that the compression damage to the middle columns of a subway station with a higher relative stiffness ratio is more serious while the tensile damage is slighter under the same earthquake motion. The relative stiffness has a significant influence on ground surface deformation, ground acceleration, and station structure deformation. However, the effect of the relative stiffness on the deformation of the bottom slab of the subway station is small. The research results can provide a reference for seismic fortification of subway stations in the soft soil area.

• Journal of the Earthquake Engineering Society of Korea
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• 제23권6호
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• pp.311-319
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• 2019

The number of aged bridges is increasing so that bridges over 30 years old account for about 11% of all bridges. Consequently, the development of a seismic performance evaluation method that considers the effects of ageing is essential for a seismic retrofitting process for improvement of the seismic safety of existing old bridges. Assessment of the damage situation of bridges after the recent earthquakes in Korea has been limited to the bearings, anchor, and concrete mortar on piers. The purpose of this study is to evaluate the seismic responses of PSC box girder bridges by considering the ageing effect of rubber bearings (RBs) and lead-rubber bearings (LRBs). The modification factor proposed by AASHTO is used to take into account the ageing effect in the bearings. PSC box girder bridges with RBs and LRBs were 3D modeled and analyzed with the OpenSEES program. In order to evaluate the ageing effect of RBs and LRBs, 40 near fault and 40 far field records were used as the input earthquakes. When considering the effect of ageing, the displacement responses and shear forces of bridge bearings (RBs and LRBs) were found to increase mostly under the analytical conditions. It was shown that the effect of ageing is greater in the case of RBs than in the case of LRBs.

• Journal of Haehwa Medicine
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• 제27권2호
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• pp.11-20
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• 2018

Objectives : Coronary and cerebrovascular disease with high mortality is a major factor in arteriosclerosis. Pro-inflammatory cytokines damage vascular endothelial cells, leading to vascular inflammation. These vascular inflammation can build up cholesterol and thrombus to cause atherosclerosis. Methods : In this study, we researched the effect of ChungHyul-Plus for vascular inflammation in human umbilical vein endothelial cells (HUVECs) stimulated with tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$). Change in mRNA expression of inflammatory cytokines (CCL5, CXCL8, CX3CL1, and MCP-1), cell adhesion molecules (VCAM-1 and ICAM-1), and anti-inflammation modulators (KLF2 and eNOS) were quantified by qRT-PCR. Results : ChungHyul-Plus decreased expression of inflammatory cytokines and cell adhesion molecules and increased anti-inflammation modulators expression in $TNF-{\alpha}$ stimulated HUVECs. Conclusions : These results suggest that ChungHyul-Plus can be used in the treatment and prevention of vascular inflammation and arteriosclerosis.

• Journal of Marine Bioscience and Biotechnology
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• 제13권2호
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• pp.86-93
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• 2021

A high salt diet contributes to kidney damage by causing hypoxia and oxidative stress. Recently, an increase in dietary salt has been reported to induce an inflammatory phenotype in immune cells, further contributing to kidney damage. However, studies on the exact mechanism and role of a high salt diet on the inflammatory response in the kidneys are still insufficient. In this study, a cisplatin-induced acute kidney injury model using C57BL/6 mice was used to analyze the effect of salt intake on kidney injury. Results showed that high salt administration aggravated kidney edema in mice induced by treatment with cisplatin. Moreover, the indicators of kidney and liver function impairment were significantly increased in the group cotreated with high salt compared with that treated with cisplatin alone. Furthermore, the exacerbation of kidney damage by high salt administration was also associated with a decrease in the number of cells in the immune regulatory system. Additionally, high salt administration further decreased renal perfusion functions along with increased cisplatin-induced damage to proximal tubules. This was accompanied by increased expression of T cell immunoglobulin, mucin domain 1 (a biomarker of kidney injury), and Bax (a pro-apoptotic factor). Moreover, cisplatin-induced expression of proinflammatory mediators and cytokines, including cyclooxygenase-2 and tumor necrosis factor-α in kidney tissue, was further increased by high salt intake. Therefore, these results indicate that the kidney's inflammatory response by high salt treatment can further promote kidney damage caused by various pathological factors.

• The Korea Journal of Herbology
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• 제33권1호
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• pp.47-55
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• 2018

Objectives : The current study is to evaluate the hepatoprotective effect of youngyanggak-san (YGS) on thioacetamide (TAA)-induced acute liver injury in rats. Methods : YGS is composed of Glycyrrhizae Radix, Asiasari Radix, Cimicifugae Rhizoma, Saigae Tataricae Cornu. While N-YGS (non-youngyanggak-san) doesn't include Saigae Tataricae Cornu. Two samples were administrated TAA together for 3 days. Thirty-six rats were divided into four groups. Rats except for the normal group were received TAA (200 mg/kg of body weight, I.P) were divided into three groups (n=9/group) : Group 1 (TAA only), Group 2 (TAA + 200 mg/kg YGS) and Group 3 (TAA + 200 mg/kg N-YGS). Acute liver damage confirmed using histological examination, The factors associated with oxidative stress and liver function activity measured in serum. Also, expressions of inflammation related proteins were investigated by western blot analysis. Results : Oxidative stress factors such as ROS and $ONOO^-$ in the Group 2 was manifested by a significant rise compared with Group 1. YGS markedly decreased the elevated ROS and $ONOO^-$. Furthermore, YGS significantly reduced the levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) The nuclear $factor-{\kappa}B$ ($NF-{\kappa}B$) activation induced by TAA led to increase both inflammatory mediators and cytokines. While YGS administration remarkably suppressed such the overexpression. In addition, the histopathological analysis showed that the liver tissue lesions were improved obviously in YGS treatment. Conclusion : YGS provided a hepatoprotective effect on acute liver damage through the suppression of oxidative stress. Especially, this effect enhanced markedly when Saigae Tataricae Cornu is included.