• Title/Summary/Keyword: ADHESION

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Re-adhesion control performance improvement for a vector controlled electric motor coach (백터제어 전동차의 재점착 성능개선에 관한 연구)

  • Byun Yeun-Sub;Lee Byung-Song;Han Kyung-Hee;Bae Chang-Han
    • Proceedings of the KSR Conference
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    • 2004.10a
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    • pp.1455-1460
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    • 2004
  • In electric motor coaches, when the adhesion force coefficient between rail and driving wheel decreases suddenly, the electric motor coach has slip phenomena. The characteristics of adhesion force coefficient is strongly affected by the conditions between rails and driving wheels, such as moisture, dust, and oil on the rails and so on. This paper proposes the vector control structure for the improved re-adhesion control with paralleled control of induction motors under the sudden variation of the adhesion force coefficient.

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Selection of Flavonoids Inhibiting Expression of Cell Adhesion Molecules Induced by Tumor Necrosis Factor- a in Human Vascular Endothelial Cells (종양괴사인자에 의하여 유도된 혈관내피세포의 Cell Adhesion Molecules 발현을 억제시키는 플라보노이드 선별)

  • 최정숙;최연정;박성희;이용진;강영희
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.31 no.6
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    • pp.1134-1141
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    • 2002
  • Adhesion of leukocytes to the activated vascular endothelium and their subsequent recruitment/migration into the artery wall are key features in the pathogenesis of atherosclerosis and inflammatory diseases. These features have been mediated by cell adhesion molecules including vascular cell adhesion molecule-1 (VCAM-1) and in tracellular cell adhesion molecule-1 (ICAM-1). This study examined whether flavonoids inhibit the pro-inflammatory cytokine TNF-$\alpha$-induced monocyte adhesion via a modulation of the protein expression of VCAM-1 and ICAM-1 of human umbilical vein endothelial cells (HUVECs). TNF-$\alpha$ markedly increased the adhesion of THP-1 monocytes to endothelial cells and induced the expression of VCAM-1, ICAM-1 and E-selectin proteins in HUVECs. Micromolar concentrations of the flavones luteolin and apigenin and the flavonol quercetin near completely blocked the monocyte adhesion to the activated endothelial cells and the induction of these adhesion molecules. However, equimicromolar catechins of (-)epigallocatechin gallate and (+)catechin, the flavonol myr- icetin and the flavanones of naringin and hesperidin had no effect on TNF-$\alpha$-activated monocyte adhesion. (-)Epigallocatechin gallate, (+) catechin, and naringin did not attenuate the TNF-$\alpha$ induction of these adhesion molecules. Furthermore, culture with luteolin and apigenin strongly blocked the expression of TNF-$\alpha$-induced VCAM-1 mRNA and modestly attenuated ICAM-1 mRNA. Quercetin modestly decreased the TNF-$\alpha$-activated VCAM-1 and ICAM-1 mRNAs. These results demonstrate that flavonoids classified as flavones and flavonols may inhibit monocyte adhesion to the TNF-$\alpha$-activated endothelium, most likely due to a blockade of expression of functional adhesion molecules down-regulated at the transcriptional level, indicating a definite linkage between the chemical structure of flavonoids and the expression of cell adhesion molecules. Furthermore, the antiathero-genic feature of flavonoids appears to be independent of their antioxidant activity.

ORIGINAL ARTICLE - Adhesion of Streptococcus mutans and Streptococcus sobrinus to different types of self-ligating brackets

  • Yang, Pil-Seung;Yu, Yoon-Jeong;Cha, Jung-Yul;Hwang, Chung-Ju
    • The Journal of the Korean dental association
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    • v.50 no.7
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    • pp.394-406
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    • 2012
  • Objective: The adhesion capabilities of different types of self-ligating brackets were measured with respect to Streptococcus mutans and Streptococcus sobrinus. Methods: Five types of self-ligating brackets (Clippy-C; Mini Clippy; Clarity-SL; Speed; Damon 3) were used for the experiment group and composite resin brackets (Spirit-MB), metal brackets (Victory) and polycrystalline alumina brackets (Clarity) were used for the control group. In order to assess adhesion of bacteria to the brackets, the brackets were cultured for 3, 6 and 24 hours in media containing bacteria and 20% sucrose. Results: There was no statistic difference in adhesion amount of Streptococcus mutans and Streptococcus sobrinus according to the types of brackets. A total adhesion amount according to bracket type was different. An extended incubation time increased adhesion amount. Observation under scanning electron microscope showed that Streptococcus sobrinus adhered more to Clippy-C and Victory rather than to Clarity-SL. Conclusions: Clarity-SL, a self-ligating esthetic bracket was confirmed to show lower bacterial adhesion to cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus group than other self-ligating brackets or conventional brackets, which suggests that proper use of self-ligating esthetic brackets might even be better in preventing tooth surface decalcification.

Inhibitory effect of the extract of Catalpa ovata G. Don. on endothelial adhesion molecule expression (개오동나무 추출물의 내피세포 부착분자 발현 억제 효과)

  • Choi, Byung-Min;Chong, Myong-Soo;Song, Ho-Joon
    • The Korea Journal of Herbology
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    • v.22 no.4
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    • pp.137-143
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    • 2007
  • Objectives : Catalpa ovata G. Don (Bignoniaceae) has been shown to possess a variety of pharmacological activities. However, the effect of Catalpa ovata G. Don on endothelial adhesion molecule expression has not been reported. Methods : To examine the effect of Catalpa ovata G. Don on the expression of adhesion molecules in human umbilical vein endothelial cells (HUVECs) stimulated with tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), we used various methods such as Western blot analysis, reverse tranascription-polymerase chain reaction (RT-PCR), and luciferase activity assay. Results : 1. The extract of Catalpa ovata G. Don inhibited the expression of intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in HUVECs stimulated with TNF-${\alpha}$. 2. The extract of Catalpa ovata G. Don reduced TNF-${\alpha}$-induced adhesion of leukocytes to HUVECs. 3. In addition, The extract of Catalpa ovata G. Don inhibited the promoter activities of ICAM-1 and VCAM-1. Conclusions : These results that Catalpa ovata G. Don may be beneficial in the treatment of inflammatory such as atherosclerosis.

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Effects of Plasma Lipoproteins on Expression of Vasular Cell Adhesion Molecule- in Human Microvasuclar Endothelial Cells (혈관내피세포에서 Vascular Cell Adhesion Molecule-1 발현에 대한 혈장 지단백의 효과)

  • 박성희
    • Journal of Nutrition and Health
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    • v.31 no.8
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    • pp.1235-1243
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    • 1998
  • Although an elevated plasma level of high density lipoprotein (HDL) is known as a protective component against the development of atherosclerosis and ensuing coronary heart diseases, the related mechanisms are still not established . It has been clearly demonstrated in the early stages of atherogenesis that adhesion of monocytes and lymphocytes to the vascular endothelium is enhanced via adhesion molecules, and that monocytes and macrophages accumulate in the subendothelial space. The present study has investigated whether isolated plasma HDL plays a role in protection against atherogenesis by inhibiting the expression of vascular cell adhesioin molecule-1(VCAM-1) on the endothelial cells. Effects of plasma native low density lipoprotein (LDL) and ac ethylated LDL(AcLDL) on VCAM-1 expression were also examined by using an immunocytochemical technique. While plasma HDL did not alter the basal expression of VCAM-1 , lipopolysaccharide(LPS) induction of this adhesion modlecule was markedly inhibited at a phyaiological concentration of HDL. In contrast, 30$\mu\textrm{g}$ protein/ml AcLDL increased sifnificantly both basal VCAM-1 expression and its LPD induction , suggesting that this modified LDL enhances leukocyte adhesiion to endothelial cells. Unlike AcLDL , plasma native LDL inhibited significantly VCAM-1 expression. This indicates that LDL did not undergo oxidative modificantion while incubated with endothelial cells. These results suggest that plasam HDL may inhibit atherogenesis by reducing the expression of adhesion molecules, which is a protective mechanism independent of tis reverse cholesterol transport function . Modified LDL is a potent iducer for adhesion molecules in vascular endothelical cells and could play a role in the pathogenesis of atherosclerosis by adhering to blood cells.

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