• Computers and Concrete
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• v.26 no.6
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• pp.467-482
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• 2020

This research focused on analyzing the post-fire behavior of high-performance concrete-filled steel tube (CFST) columns, with the concrete containing tire rubber and steel fibers, under axial compressive loading. The finite element (FE) modeling of such heated columns containing recycled aggregate is a branch of this field which has not received the proper attention of researchers. Better understanding the post-fire behavior of these columns by measuring their residual strength and deformation is critical for achieving the minimum repair level required for structures damaged in the fire. Therefore, to develop this model, 19 groups of confined and unconfined specimens with the variables including the volume ratio of steel fibers, tire rubber content, diameter-to-thickness (D/t) ratio of the steel tube, and exposure temperature were considered. The ABAQUS software was employed to model the tested specimens so that the accurate behavior of the FE-modeled specimens could be examined under test conditions. To achieve desirable results for the modeling of the specimens, in addition to the novel procedure described in this research, the modified versions of models presented by previous researchers were also utilized. After the completion of modeling, the load-axial strain and load-lateral strain relationships, ultimate strength, and failure mode of the modeled CFST specimens were evaluated against the test data, through which the satisfactory accuracy of this modeling procedure was established. Afterward, using a parametric study, the effect of factors such as the concrete core strength at different temperatures and the D/t ratio on the behavior of the CFST columns was explored. Finally, the compressive strength values obtained from the FE model were compared with the corresponding values predicted by various codes, the results of which indicated that most codes were conservative in terms of these predictions.

• Proceedings of the Ginseng society Conference
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• 1998.06a
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• pp.300-311
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• 1998

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), one of the most notorious toxic environmental pollutants, induces various toxic effects in many organs including testes and is regarded as an endocrine disruptor. Korean ginseng, on the other hand, has been well known for its preventive effects on lox- ins, diabetes melltus and hyperlipidemia. We investigated, histopathologically, the effect of Korean Red ginseng water extract (KR-WE) on guinea pig testes damaged by TCDD. Ninety guinea pigs were divided into 6 groups: normal control (NC) group received vehicle and saline; TCDD,1191kg b.w., was administered intraperitoneally to the single dose TCDD-treated (77) group; 100 mghg b.w.16 and 200mg1kg b.w./d KR-WE were injected intraperitoneally to the preventive groups (PIOO and P2OO, respectively) for 28 days from 1 week before TCDD injection, and to the therapeutic groups (CIOO and C2OO, respectively) for 14 days since 1 week after TCDD administration. Increment of body weight was retarded to a larger extent by TCDD. Moreover, body weight of the 77 group decreased significantly 7 days after TCDD exposure, while that of preventive groups kept increasing. Decrease in body weight was not observed in KR-WE-treated groups. Weight decrease in testes caused by TCDD was remarkably protected by KR-WE. Testicles in 77 group displayed decreased tubular size and maturation arrest at the primary or secondary spermatocyte stage. On the other hand, maturation arrest in germ cells by TCDD was improved in KR-WE treated groups. Almost complete protection of the testes was observed in PIOO and P2OO groups. In addition, the therapeutic effect was noticed in C 100 and C2OO groups. These results provided strong evidence that Korean Red ginseng might be a useful agent for the prevention and treatment of testicular damage induced by environmental pollutants.

• Applied Microscopy
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• v.34 no.4
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• pp.241-254
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• 2004

Kidney had recovery functions against toxicants, ischemia, reperfusion-induced damage, acute-renal failure (ARF). Urinary epidermal growth factor (EGF) is produced by the juxtaglomerular apparatus. Kidney accumulates or excretes the EGF. In case of renal diseases, excreted EGF was decreased. The aim of this study is to evaluate the effects squalene (SQ) on the prevention of experimental acute renal failure induced by glycerol. In case of in vitro study, we investigated the expression of EGF by RT-PCR. After the proximal tubular cells was isolated, glycerol (1, 2, 4 mM) or glycerol plus squalene (0.1, 0.05 or 0.1%) was added. In case of in vivo study, we investigated the changes of BUN, creatine, and ultrastructure. Experimental groups were divided into four groups. Group 1 was normal mouse. Group 2 was injected with SQ only (180 mg/kg). Group 3 was not treated with squalene after intraperitoneal contamination of glycerol (50%, 8 ml/kg). And, Group 4 was treated with squalene (180 mg/kg) after intraperitoneal contamination of glycerol (50%, 8 ml/kg). All groups were used to 7 mice. In the results, we investigated the glycerol induced renal failure. The expression of EGF mRNA was decreased in renal proximal tubules when treated with only glycerol. SQ increased the mRNA expression of EGF in renal proximal tubules. SQ also quickly recovered the levels of BUN and creatine compared with those of mice treated with only glycerol (P<0.01). In case of ultrastructure, group 3 had heavily damaged mitochondria, but, mitochondria in group 4 had evidences of the recovery. It was concluded that SQ had the recovery effects for the glycerol-induced acute renal failure.

• Korean Journal of Veterinary Pathology
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• v.3 no.1
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• pp.15-25
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• 1999

To elucidate the mechanism of age-related development in FGS/NgaKIST mice with spontaneous glomerulosclerotic lesion, we examined expression and localization of various cytokine mRNA in the kidney in the progression of diseases. This mouse model is the first to develop spontanously occuring glomerosclerotic lesion in the kidney. In this study, we detected the up-regulation of local cytokine genes such as IL-1$\beta$, IL-2, IL-6, IL-10, TNF-$\alpha$, TGF-$\beta$, and IFN- $\gamma$ in the kidneys. In RT-PCR and Southern blot analysis, we detected gradual expressions of cytokine mRNA of IL-1$\beta$, IL-2, IL-6, IFN- $\gamma$, and TNF $\alpha$ mRNA during the course of disease. Other cytokines including IL -10 and TGF -$\beta$ were found to be appeared the slightly expressed level at 3 to 12 weeks before onset of inflammatory lesion but they are highly expressed at the end-stage of the disease accompaning high proteinurea and wasting. In situ RT-PCR, each cytokine mRNA were specifically localized in a variety of cells including mesangial, endothelial, parietal epithelial, tubular epithelial, arterial muscle cell, and infiltrated inflammatory cells. In addition, TNF - $\alpha$was detected moderately in the visceral and parietal epithelial cell, but weakly in endothelial and mesangial cells, whereas IL-1 $\beta$ and IL -6 were strong in mesangial regions. IL-6 and TNF- $\alpha$ was highly localized in the damaged proximal and collecting tubules. Especially, TGF -$\beta$ mRNA was highly found in mesangial cells within glomerulus and interstitium during the end-stage of this disease.. These results indicate that pro inflammatory cytokines such as IL-1 $\beta$, IL-2, IL-6, and TNF- $\alpha$ were gradually expressed from the early stage of this disease to the end-stage, and that IL-10 and TGF-$\beta$ may be important in the accumulation of extracellular matrix(ECM) within glomerulus and periglomerular fibrosis in the progression of this disease as well as tissue destruction in end-stage of this disease.