• Transactions of Materials Processing
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• 제9권1호
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• pp.80-87
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• 2000

The static softening behavior of SCM 440 could be characterized by the hot torsion test in the temperature ranges of 90$0^{\circ}C$~110$0^{\circ}C$and strain rate ranges of 0.05/sec~5/sec. Interrupted deformation was performed with 2 pass deformation in the pass strain ranges of 0.25$\varepsilon$p~3$\varepsilon$p and interrupted time ranges of 0.5~100sec. The dependences of process variables, pass strain ($\varepsilon$i), stain rate ($\varepsilon$), temperature (T) and interpass time (ti), on static recrystallization (SRX) and metadynamic recrystallization (MDRX)were individually predicted from the modified Avrami's equations, The dependence of pass strain on MDRX was neglectable. Comparison of the softening kinetics between MDRX and SRX showed that the rate of MDRX was more rapid than that of SRX for the same deformation variables. Controlled multipass deformations were performed using static and metadynamic recrystallization of SCM 440.

• Transactions of the Korean Society of Automotive Engineers
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• 제14권3호
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• pp.133-141
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• 2006

The Low cycle fatigue behavior of 11.7Cr-1.1Mo heat-resisting steel has been investigated under strain-controlled conditions with mean stresses at room temperature and $300^{\circ}C$. For the tensile mean stress test, the initial high tensile mean stress generally relaxed to zero at room temperature, however, at $300^{\circ}C$ initial tensile mean stress relaxed to compressive mean stress. Low cycle fatigue lives under mean stress conditions are usually correlated using modifications to the strain-life approach. Based on the fatigue test results from different stain ratio of -1, 0, 0.5, and 0.75 at room temperature and $300^{\circ}C$, the fatigue damage of the steel was represented by using cyclic strain energy density. Total strain energy density considering mean stress indicated well better than not considering mean stress at $300^{\circ}C$. Predicted fatigue life using Smith-Watson-Topper's parameter correlated fairly well with the experimental life at $300^{\circ}C$.

• Journal of Life Science
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• 제19권10호
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• pp.1444-1450
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• 2009

The number of patients with immune- mediated dermatitis such as contact dermatitis is increasing year by year. Allergic contact dermatitis is a complex phenomenon that involves resident epidermal cells, fibroblasts, and endothelial cells, as well as invading leukocytes that interact with each other under the control of a network of cytokines and lipid mediators. It is a cell-mediated immune reaction, which occurs after susceptible individuals are exposed to sensitizing chemicals, and characteristic eczematous reaction is seen at the point of contact with an allergen. In this study, we investigated the allergy prevention effects of quercetin on mast cell-mediated allergic inflammation in BALB/c mice. BALB/c mice were sensitized with 40 ${\mu}l$ of 1.5% picryl choloride (PCL) to the left and right ear each. Total serum IgE levels and histamine levels were measured by the sandwich ELISA method using mouse IgE, histamine measuring kit. For histopathological examination, paraffin sections were stained with hematoxylin and eosin(HE) or toluidine blue(TB). Ear swelling responses were much weaker in the high-dose group (100 mg/kg) than the control group (0 mg/kg). The number of mast cells showed a significant decrease in the high-dose group (100 mg/kg) compared to the control group (0 mg/kg). Degranulation of mast cells was also confirmed by Toluidine Blue (TB) staining method. Both total serum IgE and histamine levels were significantly decreased in the high-dose group (100 mg/kg) compared to other groups. These findings suggest a certain relationship between the elevation of IgE, histamine levels and the degranulation of mast cells. These results show that the pharmacological actions of quercetin indicate its potential activity for prevention of allergic inflammatory diseases through the down-regulation of mast cell activation.

• Nutrition Research and Practice
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• 제9권6호
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• pp.586-591
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• 2015

BACKGROUND/OBJECTIVES: Reactive oxygen species (ROS) formation is closely related to miconazole-induced heart dysfunction. Although rhamnetin has antioxidant effects, it remained unknown whether it can protect against miconazole-induced cardiomyocyte apoptosis. Thus, we investigated the effects of rhamnetin on miconazole-stimulated H9c2 cell apoptosis. MATERIALS/METHODS: Cell morphology was observed by inverted microscope and cell viability was determined using a WelCount$^{TM}$ cell proliferation assay kit. Miconazole-induced ROS production was evaluated by fluorescence-activated cell sorting with 6-carboxy-2',7'-dichlorofluoroscein diacetate ($H_2DCF$-DA) stain. Immunoblot analysis was used to determine apurinic/apyrimidinic endonuclease 1 (APE/Ref-1) and cleaved cysteine-aspartic protease (caspase) 3 expression. NADPH oxidase levels were measured using real-time polymerase chain reaction. RESULTS: Miconazole (3 and $10{\mu}M$) induced abnormal morphological changes and cell death in H9c2 cells. Rhamnetin enhanced the viability of miconazole ($3{\mu}M$)-treated cells in a dose-dependent manner. Rhamnetin (1 and $3{\mu}M$) treatment downregulated cleaved caspase 3 and upregulated APE/Ref-1 expression in miconazole-stimulated cells. Additionally, rhamnetin significantly reduced ROS generation. CONCLUSIONS: Our data suggest that rhamnetin may have cytoprotective effects in miconazole-stimulated H9c2 cardiomyocytes via ROS inhibition. This effect most likely occurs through the upregulation of APE/Ref-1 and attenuation of hydrogen peroxide levels.

• Conservation Science in Museum
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• 제15권
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• pp.96-121
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• 2014

Portrait of Sim Huisu is a seventeenth-century Joseon portrait of a meritorious vassal. The National Museum of Korea currently owns two portraits of Sim Huisu, which are the eldest son's family and by the eldest grandson of the family's second eldest son. Both were donated in 1980. Portraits were still in its original mounting, but the supporting silk had been damaged and stained in a flood. Conservation treatment was undertaken to restore the original style, and scientific analysis, such as, X-ray, XRD, XRF and Graff "C" stain, was conducted to study the materials and painting techniques. The support silk was found to be refined fibroin and a plain weave consisting of two weft threads and one warp thread. The lining papers were found to be bamboo fiber paper of first layer in China and Korean traditional mulberry paper in second. Various pigments were identified in the painting, including white lead, cinnabar, atacamite, ink stick, azurite, silver, and gold. The study also confirmed the use of the back painting, with colors such as white ^{White Lead}, green ^Atacamite, orange ^Minium, black ^{Ink Stick}, and yellow ^Dye. Also, it was found that stick ink or dye was used with white lead.

• Biomedical Science Letters
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• 제5권1호
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• pp.119-129
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• 1999

This study was aimed to investigate the enzyme-histochemical localization and characteristics of alkaline and acid phosphatase extracted from adult of Echinostoma hortense. Using the Gomori calcium stain and the Gomori lead nitrate satin method, we found that the alkaline and acid phosphatases were localized mostly in the intestine, vitellaria and pharynx of Echinostoma hortense. The three isozymes of alkaline phosphatase and two isozymes of acid phosphatase were separated from Echinostoma hortense by electrophoresis. The isozymes of alkaline phosphatase were 145.9, 207.5, 220.8 kDa and the isozymes of acid phosphatase were 179.5 and 209.4 kDa. The activity of alkaline phosphatase was denatured completely after heating at 9$0^{\circ}C$ for 12 seconds. The optimum pH and temperature for activity of alkaline phosphatase were about pH 9 and 4$0^{\circ}C$, while the optimum pH for activity of acid phosphatase was about pH 5. The maximum activity of alkaline phosphatase was at 189 unit, but maximum activity of acid phosphatase was at 71 unit As the result from above, we observed that alkaline and acid phosphatases funtion mainly in the alimentary tract and vitellaria. Echinostoma hortense performs the parasitism in the intestine of host by using proper isozyme of phosphatase.

• Korean Journal of Food Science and Technology
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• 제29권5호
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• pp.1028-1032
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• 1997

The strain No. 33, which produces cellulose-degrading enzyme, was isolated from soil. Yellow halo was identified when the culture supernatant of the strain was loaded onto agar plate containing 2.0% CMC using paper disc method. From scanning electron microscopic observation, the morphology of the stain was rod-shaped. For identification, several biochemical characteristics were tested, and this strain was identified to Bacillus sp. So, we named this strain as Bacillus sp. No. 33. The maximal growth was observed when the stain was cultured in the medium containing 1.0% glucose, 3.0% yeast extract, 0.5% $KH_2PO_4$, 0.02% $MgSO_4{\cdot}7H_2O$, pH 7.0 at $30^{\circ}C$ for 39 hours with shaking. The maximal enzyme production was accomplished using the medium containing 4.0% CMC, 2.0% yeast extract, 0.5% $KH_2PO_4$, 0.04% $MgSO_4{\cdot}7H_2O$, pH 7.0 at $30^{\circ}C$ for 42 hours with shaking.

• Nuclear Medicine and Molecular Imaging
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• 제42권3호
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• pp.229-234
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• 2008

Purpose: A urea breath test (UBT) using C-14 or C-13 has been developed for identifying Helicobacter (H) pylori infection on the basis of urease production with release of labeled $CO_2$. We investigated if the C-14 and C-13 UBT have the difference to reflect the presence and degree of H. pylori infection detected by gastro-duodenoscopic biopsies (CBx) in the same patients. Materials and methods: Thirty eight patients (M:F = 28:10, age $53.4{\pm}13.0$ yrs) with upper gastrointestinal symptoms such as indigestion, gastric fullness or pain consecutively underwent C-14 UBT, GBx and C-13 UBT within one week before medications. For the C-14 UBT, a single breath sample was collected at 10 minutes after ingestion of C-14 urea (37 KBq) capsule and counting was done in a liquid scintillation counter for 1 minute, and the results were classified as positive (${\ge}$ 200 dpm), intermediate (50-199 dpm) or negative (50 dpm). For the C-13 UBT, the results were classified as positive (${\ge}2.5\%_{\circ}$) or negative ($<2.5\%_{\circ}$). The results of GBx with Giemsa stain were graded 0 (normal) to 4 (diffuse) according to the distribution of H. pylori by the Wyatt method. We compared C-14 UBT and C-13 UBT results with GBx grade as a gold standard. Results: The prevalence of H. pylori infection by GBx with Giemsa stain was 25/38 (65.8%). In the assessment of the presence of H. pylori infection, the C-14 UBT global performance yielded sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 92.0%, 92.3%, 95.8%, 91.7% and 92.1%, respectively. However, the C-13 UBT had sensitivity, specificity, PPV, NPV and accuracy of 96.0%, 84.6%, 92.3%, 91.7% and 92.1%, respectively. The more significant correlation in C-14 than C-13 UBT (r=0.948 vs r=0.819, p <0.001) was found between the value of UBT and the grade of distribution of H. pylori infection. Conclusion: We conclude that the diagnostic performance between C-14 and C-13 UBT to detect H. pylori infection is not significantly different, but the value of C-14 UBT more significantly reflects the degree of bacterial distribution.

• Transactions of Materials Processing
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• 제7권2호
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• pp.158-167
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• 1998

Hot restoration mechanism flow stress and stain of the Al2024 composites reinforced with 1,8,15,36, and $44{\mu}m\;SiC_p$(10 vol. %) were studied by hot torsion tests. The hot restoration mechanism of all the composites was found to be dynamic recrystallization(DRX) at $320^{\circ}C$ while that of the composites reinforced with 1 and $8{\mu}m\;SiC_p$ was found to be dynamic recovery(DRX) at $480^{\circ}C$. It was found that the Al2024 composite with $15{\mu}m\;SiC_p$ showed the highest flow stress(${\sim}$223 MPa) at $320^{\circ}C$ under a strain rate of 1.0/sec. Also the highest flow strain of the composites was obtained at $430^{\circ}C$. The com-posites reinforced with 1 and $8{\mu}m\;SiC_p$ showed lower flow stress and higher flow strain at $480^{\circ}C$ than those of the composites reinforced with 15, 36, and $44\;{\mu}m\;SiC_p$ These result were discussed in relation to the transition of the hot restoration mechanism. $DRX{\leftrightarrow}DRV$. The dependence of flow stress on strain rate and temperature was attempted to fit with the hyperbolic sine equation ($\dot{\varepsilon}=A[sinh({\alpha}{\cdot}{\sigma}_p]^n$ exp(-Q/RT)and Zener-Hollomon parameter($Z=\;\dot{\varepsilon}\;exp(Q/RT))$.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제31권2호
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• pp.116-129
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• 2005

Distraction osteogenesis is a new bone formation technique. There is a advantage of the environmental adaptation when distraction force is applied to the gap between osteotomy lines. But it has a disadvantage of long-term wearing of the appliance and long consolidation period. Therefore we make an effort to reduce it and repair normal function. Extracellular matrix proteins have a function to control the cellular growth, migration, shape and metabolism. In these, hyaluronic acid is a member of polysaccharide glycosaminoglycans (GAGs) and has a important function as bone formation and osteoinduction property. Purpose : In this experimental study in rabbit mandibular distraction osteogenesis, we investigated the bone enhancing property of hyaluronic acid and the expression of extracellular proteins such as osteocalcin and osteonectin. Materials and Methods : The experimental study was carried out on 24 Korean male white rabbits (both mandibular body, n=48). Distraction group was divided to distraction experimental (A, n=16) and distraction control (B, n=16) by the application of hyaluronic acid (Hyruan, LGCI, Seoul, Korea). Normal control group (C, n=16) was only osteotomized. After 5 days latency, distraction devices were activated at a rate of 1.4 mm per day (0.7 mm every 12hours) for 3.5 days. Animals were sacrificed at postoperative 3, 7, 14, and 28 days. H&E stain and immunohistochemical stain was done on decalcified section. Additionally RT-PCR analysis was done for the identification of the expression of osteocalcin and osteonectin. Results : The bone formation in distraction experimental group was much more than that in distraction and normal control group at postoperative 28 days. In immunohistochemical stain, osteocalcin was enhanced at only postoperative 14 days, but osteonectin was not different at each post-operation days. In RT-PCR analysis, osteocalcin was not different at each post-operation days, but osteonectin was strongly expressed in distraction experimental group at postoperative 7 days. The expression of osteocalcin and osteonectin was elevated during the healing period. Conclusion : We found the good bone formation ability of hyaluronic acid in distraction osteogenesis through the immunohistochemistry and RTPCR analysis to osteocalcin and osteonectin, known as a bone formation marker. The application of hyaluronic acid in distraction osteogenesis is a method to reduce the consolidation period.