• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.98-107
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• 2004

The objectives of this research are to establish the criteria of peel occurrence considering the shape of bond terminus and to compare the strength properties of some adhesive joints. The criteria of feel occurrence at the bond terminus was suggested. Peel loads of some adhesive joint(butt joint, T -shape specimen, single lap joint) were determined from tensile tests. Principal stress distributions of these joints were determined from finite element method analysis. Then, peel occurrence was estimated with intensity of stress singularity ' $K_{prin.}$' when the terminus shape was square, with average principal stress when the terminus shape was rounded. The conclusions are summarized as follows; (1) In the non-filleted model(e.g., butt joint, T-shape specimen), principal stress shows singularity at the bond terminus, intensity of stress(principal stress) singularity ' $K_{prin.}$&apso; can use as the criteria of peel occurrence at the bond terminus. (2) In the filleted model(e.g., single lap joint), principal stress doesn't show singularity at the bond terminus. Average principal stress can use as the criteria of peel occurrence at the bond terminus.'t show singularity at the bond terminus. Average principal stress can use as the criteria of peel occurrence at the bond terminus.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.5
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• pp.62-73
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• 2005

The objects of this research are to establish the criteria of peel occurrence considering the shape of bond terminus and to compare the strength properties of adhesive joint of different three type such as butt joint, T-shape, and single lap Joints. The criteria of peel occurrence at the bond terminus was suggested. Peel loads of three type adhesive joint (butt Joint, T-shape specimen, single lap joint) were determined from tensile tests. Principal stress distributions of these joints were determined from finite element method analysis. Then, peel occurrence was estimated with stress singularity factor$(K_{prin})$ when the terminus shape was square, with average principal stress when the terminus shape was rounded. The conclusions are summarized as follows; (1) In the non-filleted model(e.g., butt joint, T-shape specimen), principal stress shows singularity at the bond terminus, intensity of stress(principal stress) singularity $(K_{prin})$ can use as the criteria of peel occurrence at the bond terminus. (2) In the filleted model(e.g., single lap joint), principal stress has not affected singularity at the bond terminus. Average principal stress$(K_{av})$ can use as the criteria of peel occurrence at the bond terminus.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.05a
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• pp.168-171
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• 2001

Due to intrinsic load eccentricity, severe peel stress concentration occurs at both ends of the single-lap joint. To avoid load eccentricity as well as the singular tensile peel stress in the joint interface, composite wavy-lap joint is proposed. In this paper, refined 3-D stress analysis of wavy-lap joint is performed by finite element method using parallel mutifrontal solver. Analysis results show that the singular tensile peel stress concentration is totally avoided in wavy-lap joint, and that loads are more evenly transferred over the length of the joint. Therefore, the strength of wavy-lap joint is significantly higher than that of conventional single-lap joint. And it is believed that even higher strengths can be obtained by optimizing the new design configuration.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.216-219
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• 2000

The adhesive bonded single-lap joint is due to its intrinsic load eccentricity problem, severe peel stresses concentration occur at both end of the joint. In this paper, new lap-joint is designed to avoid the singular peel stress, and to compare the stresses of the middle adhesive layer between the single-lap joint and the wavy-lap joint. Two adherend lay-up, i.e., [90/0/90/0]$_{2s}$ and [0/90/0/90]$_{2s}$ were consider in the study.

• Journal of Welding and Joining
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• v.17 no.4
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• pp.69-75
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• 1999

Spot welding has been used in the sheet metal joining processes because of its high productivity and convenience. In this study, predicting methods of fatigue life of spot welded joint have been investigated and fatigue and static tests were conducted with the peel-tension specimens using cold rolled steel plate(SPCC). Fatigue life of peel-tension spot welded joint was influenced by tail effect. Fatigue life evaluation using modified stress index parameter, considering the effective eccentric length, can predict the life more exactly than conventional stress index parameter.

• Journal of Microbiology and Biotechnology
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• v.28 no.7
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• pp.1094-1104
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• 2018

The peel of astringent persimmon (Diospyros kaki Thunb. cv. Cheongdo-Bansi) is a by-product of dried persimmon (gotgam). We investigated if deastringent peel extracts of persimmon cv. Cheongdo-Bansi had antioxidative and neuroprotective properties. Two different extracts were prepared: thermally and nonthermally treated persimmon peel extracts (TPE and NTPE, respectively). Both TPE and NTPE were fractionated sequentially in n-hexane, chloroform, ethyl acetate, n-butanol, and water. The TPE and NTPE ethyl acetate fractions had the highest total phenolic and flavonoid contents as well as antioxidant capacities among all the fractions. Pretreatment of neuronal PC-12 and SH-SY5Y cells with the TPE and NTPE ethyl acetate fractions increased cell viability after exposure to oxidative stress. The ethyl acetate fraction of TPE attenuated oxidative stress inside both PC-12 and SH-SY5Y cells more effectively than that of NTPE. Furthermore, the TPE and NTPE ethyl acetate fractions inhibited acetylcholinesterase and butyrylcholinesterase. Analysis of ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry results revealed gallic acid, kaempferol, kaempferol-3-O-galactoside, kaempferol-3-O-glucoside, quercetin, quercetin3-O-galactoside, quercetin-3-O-galactoside-2'-O-gallate, and quercetin-3-O-glucoside as the major phenolics of the TPE and NTPE ethyl acetate fractions. Taken together, these results suggest that the ethyl acetate fraction of deastringent persimmon peel is rich in antioxidants and has potential as a functional food to reduce oxidative stress.

• Journal of Physiology & Pathology in Korean Medicine
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• v.38 no.1
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• pp.10-15
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• 2024

Previous studies have highlighted the pivotal role of the β-adrenergic receptor (β-AR) signaling pathway in stimulating cancer metastasis induced by chronic stress. According to the theory of traditional Korean medicine, chronic stress can induce Qi stagnation. Based on the traditional role of premature citrus unshiu peel in moving Qi, we hypothesized that an ethanol extract of premature citrus unshiu peel (EPCU) can attenuate chronic stress-induced cancer progression. In this study, we investigated the potential role of EPCU on modulating the adrenergic agonists-induced metastatic properties of liver cancer cells. Our findings revealed that adrenergic agonists, including norepinephrine (NE), epinephrine (E), and isoproterenol (ISO), augmented the migratory capacity of Hep3B human hepatocellular carcinoma cells, which was completely abrogated by EPCU treatment in a concentration-dependent manner. Consistently, EPCU inhibited the E-induced invasive property of Hep3B cells in a dose-dependent manner. These results suggest that EPCU efficiently attenuates adrenergic agonists-induced metastatic abilities of liver cancer cells. As a molecular mechanism, EPF suppressed the phosphorylation of major components of β-AR signaling pathway, including Src, signal transducer and activator of transcription 3 (STAT3) and ERK, induced by E treatment. Taken together, our results demonstrate that EPCU impedes the adrenergic agonists-driven metastatic potential of cancer cells by inhibiting β-AR signaling pathway. This study provides basic evidence supporting the probable use of premature citrus unshiu peel to prevent metastasis in liver cancer patients under chronic stress.

• Journal of the Korean Society of Food Culture
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• v.20 no.6
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• pp.721-730
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• 2005

Recently, epidemiological evidence has raised concerns that moderate elevation in body iron stores may increase oxidative stress and the risk of cardiovascular disease and cancer. Onion flesh or peel contains antioxidant such as flavonoids and alk(en)ylcysteine sulphoxides. This study was conducted to examine the effect of onion flesh or peel feeding on antioxidative capacity in aged rats supplemented with high dietary iron. Thirty-two Sprague-Dawley male 16-month-old rats weighing $618{\pm}6g$ were acclimated for 10 days with medium-iron diet (35ppm in diet), and blocked into 4 groups according to their body weights and raised for 3 months on either control diets (adequate iron-35ppm or high iron-350ppm) or experimental diets containing onion flesh/peel (5% w/w in diet) with high iron (350ppm). Rats fed high iron-onion peel diet had significantly high quercetin and isorhamnetin levels in plasma whereas rats fed high iron-onion flesh diet did not show. Plasma TBARS level was lowered by onion flesh or peel diet with high iron supplementation. However, there was no significant difference in cellular DNA damage in brain and kidney tissue among all experimental groups. We concluded that high iron diet (10 times higher than requirement) tend to increase oxidative stress and it is plausible that onion flesh or peel feeding enhances antioxidative capacity in the elderly even with iron supplementation.

• Journal of the Korea Concrete Institute
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• v.14 no.5
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• pp.766-773
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• 2002

The failure phenomenon of overlaid concrete structures, such as surface crack, and peel-off failure, shear bond failure in the end contact zone, was investigated due to humidity changes. To investigate this failure phenomenon, the surface tensile stress, and the shear stress, the vertical tensile stress in the contact zone were analysed using the non-linear stress-strain relationship of material such as strain-hardening- and strain-softening diagrams. Overlay thickness and overlay material were the main variables in the analyses. It is assumed that the initial surface humidity of overlaid concrete structures was 100％ r.H. With a atmospheric humidity of 55％ r.H. and two load cases for drying(LCI), curing and drying(LC2), the stress states of overlaid concrete structures were calculated. The result shows that only fictitious cracks occurred in the overlay surface of CM2O, ECM25, and no shear bond failure occurred in the contact zone without CM2O. The peel-off failure was proved to be the main cause of the damage in the overlaid concrete structures. Only for overlay thickness of 1cm occurred no peel-off failure in the case of drying after a long-term public use(LC1). In the case of curing and drying during overlay work(LC2) occurred the peel-off failure within 1.5days for all the overlaid concrete structures.

• Nutrition Research and Practice
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• v.4 no.2
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• pp.114-120
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• 2010

The effects of grape seeds extract and grape peels extract prepared from grape pomace on the activity of antioxidant enzymes, degree of lipid peroxidation in serum and liver tissue were investigated in rabbits fed on high cholesterol diet. New Zealand white rabbits were divided as follows ; 1) NOR (normal group); 2) CHOL (cholesterol group); 3) GSH (cholesterol + grape seed extract group); 4) GPE (cholesterol + grape peel extract); 5) GSP (cholesterol + grape seed powder); 6) GPP (cholesterol + grape peel powder); 7) GE (cholesterol + grape seed and peel extract); 8) GP (cholesterol + grape seed and peel powder). Eight groups of rabbits were studied for 8 weeks. At the end of the experimental period, rabbits were sacrificed and the liver tissue were removed. Then, GSH, GPx, GST, CAT and MDA in the liver were measured. In liver tissues, total glutathione contents (GSH), glutathione peroxidase (GPx) and catalase (CAT) activity, which was significantly higher by grape seed extract supplementation. The level of malondialdehyde (MDA) was lower in the serum of rabbits fed grape seed extract or grape peel powder plus cholesterol than in the serum of rabbits fed cholesterol alone. It is therefore likely that grape seed extract prepared from grape pomace functioned as antioxidants in vivo, negating the effects of the oxidative stress induced by 1% cholesterol diet. The grape seed extract was found effective in converting the oxidized glutathione into reduced glutathione, and in removing $H_2O_2$ that is created by oxidative stress. The grape peel powder was found to have small influence on reduced glutathione content, CAT and GPX activity, but it increased GST activity in liver tissues, resulting in promoting the combination of lipid peroxide and glutathione (GSH), and further, lowering the formation of lipid peroxide in the serum. Therefore, grape pomace (grape seed extract and grape peel powder) supplementation is considered to activate the antioxidant enzyme system and prevent damage with hypercholesterolemia.