• Title/Summary/Keyword: Adherent molecules

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Molecular Dynamics Study on Evaporation Process of Adherent Molecules on Surface by High Temperature Gas

  • Yang, Young-Joon;Osamu Kadosaka;Masahiko Shibahara;Masashi Katsuki;Kim, Si-Pom
    • Journal of Mechanical Science and Technology
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    • v.18 no.12
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    • pp.2104-2113
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    • 2004
  • Surface degreasing method with premixed flame is proposed as the removal method of adherent impurities on materials. Effects of adherent molecular thickness and surface potential energy on evaporation rate of adherent molecules and molecular evaporation mechanism were investigated and discussed in the present study. Evaporation processes of adherent molecules on surface molecules were simulated by the molecular dynamics method to understand thermal phenomena on evaporation processes of adherent molecules by using high temperature gas like burnt gas. The calculation system was composed of a high temperature gas region, an adherent molecular region and a surface molecular region. Both the thickness of adherent molecules and potential parameters affceted the evaporation rate of adherent molecules and evaporation mechanism in molecular scale.

MOLECULAR SCALE MECHANISM ON EVAPORATION AND REMOVAL PROCESS OF ADHERENT MOLECULES ON SURFACE BY BURNT GAS

  • Yang, Y.J.;Lee, C.W.;Kadosaka, O.;Shibahara, M.;Katsuki, M.;Kim, S.P.
    • International Journal of Automotive Technology
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    • v.7 no.2
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    • pp.121-128
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    • 2006
  • The interaction between adherent molecules and gas molecules was modeled in the molecular scale and simulated by the molecular dynamics method in order to understand evaporation and removal processes of adherent molecules on metallic surface using high temperature gas flow. Methanol molecules were chosen as adherent molecules to investigate effects of adhesion quantity and gas molecular collisions because the industrial oil has too complex structures of fatty acid. Effects of adherent quantity, gas temperature, surface temperature and adhesion strength for the evaporation rate of adherent molecules and the molecular removal mechanism were investigated and discussed in the present study. Evaporation and removal rates of adherent molecules from metallic surface calculated by the molecular dynamics method showed the similar dependence on the surface temperature shown in the experimental results.

Molecular Dynamics Study for Improving the Adhesion of Paint (도료의 부착성 개선을 위한 분자동역학적 연구)

  • Yang, Young-Joon;Lee, Chi-Woo
    • Journal of Advanced Marine Engineering and Technology
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    • v.31 no.8
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    • pp.932-938
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    • 2007
  • The interaction between adherent molecules and gas molecules was modeled in molecular scale and simulated by the molecular dynamics method in order to understand the evaporation and removal processes of adherent molecules on metallic surface using high temperature gas flow. Methanol molecules were chosen as adherent molecules to investigate effects of adhesion quantify and gas molecular collisions because the industrial oil has too complex structures of fatty acid. The effects of adherent quantify, gas temperature and surface temperature for the evaporation rate of adherent molecules and the molecular removal mechanism were investigated and discussed in the present study. Evaporation and removal rates of adherent molecules from metallic surface calculated by the molecular dynamics method showed the similar dependence on surface temperature shown in the experimental results.

Effects of Tubulyzines, Novel Microtubule-Binding Triazine Molecules, on Endothelial Progenitor Cell Differentiation

  • Park, Hyo-Eun;Lee, Soo-Young;Ahn, Hyun-Young;Shin, Jong-Cheol;Chang, Young-Tae;Joe, Young-Ae
    • Biomolecules & Therapeutics
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    • v.11 no.2
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    • pp.85-90
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    • 2003
  • Microtubule-binding molecules have been developed as anti-cancer agents to overcome the toxicities of current chemotherapeutics and also have potential for use as anti-angiogenic agents. In this work, we examined the effect of novel triazine compounds, Tubulyzines (microTUBUle LYsing triaZINE), derived from the orthogonal synthesis of a triazine library, on endothelial progenitor cell differentiation. When mononuclear cells isolated from human cord blood were cultured on fibronectin-coated plates for 7 days, all the Tubulyzine compounds A, B, and C (TA, TB, and TC) tested decreased the number of adherent cells in a dose-dependent manner in a coo. centration ranges of 2-5 to $80\mu\textrm{M}$. TA ($IC_{50}$=$20\mu\textrm{M}$) showed slightly more potent activity than TB and TC. Adherent cells treated with TA also exhibited a lower level of ability to ac-LDL uptake, with low ratios of positive cells out of total adherent cells, in a dose-dependent manner and weak expression of endothelial lineage markers, KDR, CD31, and vWF at $20\mu\textrm{M}$. Therefore, these results suggest that tubulyzine A (TA) can be effectively used for the inhibition of new vessel growth by inhibiting differentiation of endothelial progenitor cells.

Immunomodulatory activity of Salicornia herbacea L. Components

  • Im, Sun-A;Kim, Goo-Whan;Lee, Chong-Kil
    • Natural Product Sciences
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    • v.9 no.4
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    • pp.273-277
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    • 2003
  • Salicornia herbacea is an annual herb growing in salt marshes and on muddy seashores. Salicornia herbacea has been used as a fork medicine as well as a seasoned vegetable. In fork medicine, Salicornia herbacea has been used to treat a variety of diseases such as constipation, obesity, diabetes, asthma, arthritis and cancer. However, the biological mechanisms for these activities have not been characterized, nor the active components. The immunomodulatory activity of Salicornia herbacea components were studied in the present study. The components of Salicornia herbacea were prepared from the whole plant by passage through a fine screen, and then dialyzed against PBS overnight. Immunomodulatory activities of the Salicornia herbacea components were examined on a mouse macrophage cell line, RAW 264.7 cells. The Salicornia herbacea components were shown to stimulate cytokine production, nitric oxide release, and expression of surface molecules in a dose dependent manner. The Salicornia herbacea components also induced further differentiation of slightly adherent RAW 264.7 cell into strongly adherent macrophages. These results indicate that Salicornia herbacea contains immunomodulator(s) that induces activation of macrophages.

Adhesion-induced generation of oxygen free radical from human alveolar macrophages and its mechanisms (폐포대식세포의 부착에 의한 산소유리기 분비능 활성화 및 그 기전)

  • Chung, Man-Pyo;Yoo, Chul-Gyu;Kim, Young-Whan;Han, Sung-Koo;Shim, Young-Soo;Han, Yong-Chol
    • Tuberculosis and Respiratory Diseases
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    • v.43 no.2
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    • pp.210-220
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    • 1996
  • Background : Neutrophils or monocytes separated in vitro by the adherence to plastic surface are known to be activated by surface adherence itself and subsequent experimental data might be altered by surface adherence. In the process of surface adherence, adhesion molecules have a clear role in intracellular signal pathway of cellular activation. Human alveolar macrophages(HAM) are frequently purified by the adherence procedure after bronchoalveolar lavage. But the experimental data of many reports about alveolar macrophages have ignored the possibility of adhesion-induced cellular activation. Method : Bronchoalveolar lavage was performed in the person whose lung of either side was confirmed to be normal by chest CT. With the measurement of hydrogen peroxide release from adherent HAM to plastic surface and non-adherent HAM with or without additional stimulation of phorbol myristate acetate(PMA) or N-formyl-methionyl-leucyl-phenylalanine (fMLP), we observed the effect of the adherence to plastic surface. We also evaluated the effect of various biological surfaces on adhesion-induced activation of HAM. Then, to define the intracellular pathway of signal transduction, pretreatment with cycloheximide, pertussis toxin and anti-CD11/CD18 monoclonal antibody was done and we measured hydrogen peroxide in the culture supernatant of HAM. Results : 1) The adherence itself to plastic surface directly stimulated hydrogen peroxide release from human alveolar macrophages and chemical stimuli such as phorbol myristate acetate(PMA) or N-formyl-methionyl-leucyl-phenylalanine(fMLP) colud not increase hydrogen peroxide release in these adherent macrophages which is already activated. 2) PMA activated human alveolar macrophages irrespective of the state of adhesion. However, fMLP stimulated the release of hydrogen peroxide from the adherent macrophages, but not from the non-adherent macrophages. 3) HAM adherent to A549 cell(type II alveolar epithelium-like human cell line) monolayer released more hydrogen peroxide in response to both PMA and fMLP. This adherence-dependent effect of fMLP was blocked by pretreatment of macrophages with cycloheximide, pertussis toxin and anti-CD18 monoclonal antibody, Conclusion : These results suggest that the stimulatory effect of PMA and fMLP can not be found in adherent macrophage because of the activation of human alveolar macrophage by the adherence to plastic surface and the cells adhered to biologic surface such as alveolar epithelial cells are appropriately responsive to these stimuli. It is also likely that the effect of fMLP on the adherent macrophage requires new protein synthesis via G protein pathway and is dependent on the adhesion between alveolar macrophages and alveolar epithelial cells by virtue of CD11/CD18 adhesion molecules.

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Molecular and Cellular Mechanisms of Syndecans in Tissue Injury and Inflammation

  • Bartlett, Allison H.;Hayashida, Kazutaka;Park, Pyong Woo
    • Molecules and Cells
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    • v.24 no.2
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    • pp.153-166
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    • 2007
  • The syndecan family of heparan sulfate proteoglycans is expressed on the surface of all adherent cells. Syndecans interact with a wide variety of molecules, including growth factors, cytokines, proteinases, adhesion receptors and extracellular matrix components, through their heparan sulfate chains. Recent studies indicate that these interactions not only regulate key events in development and homeostasis, but also key mechanisms of the host inflammatory response. This review will focus on the molecular and cellular aspects of how syndecans modulate tissue injury and inflammation, and how syndecans affect the outcome of inflammatory diseases in vivo.

Lysyl-tRNA Synthetase Inhibits Various Shear Stress-stimulated Signaling Pathways in Endothelial Cells

  • Park, Heon-Yong
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 2008.04a
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    • pp.103-115
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    • 2008
  • Hemodynamic shear stress, the dragging force generated by blood flow, is known as an anti-atherogenic factor. We tested whether lysyl-tRNA synthetase (KRS) will be utilized as an agent controlling shear-sensing systems. KRS was previously known to be secreted as a pro-inflammatory agent. Here we found that KRS inhibited various shear-stimulated signaling pathways. We further found that KRS binds to detergent-resistant membrane (DRM), indicating that KRS binding molecules exist in DRM, specialized regions of the plasma membrane. DRM plays important roles in a variety of cellular processes and consists of gangliosides, signaling molecules and cytoskeletons. We then determined that KRS was colocalized with integrins ${\alpha}4$, ${\alpha}5$ and $av{\beta}3$. In addition, KRS was shown to be associated with sialic acid, existing at the end of gangliosides. Interestingly, the adherent effect of KRS was inhibited by pretreatment with sialic acid. Moreover, treatment of endothelial cells with neuraminidase appeared to inhibit both the KRS adhesion to endothelial cells and shear-stimulated signaling. In conclusion, KRS is likely to be utilized as a vascular regulator.

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Surface Modification of Biomaterials for Hard Tissue Substitutes to Improve Biocompatibility and Osteoconductivity (생체적합성 및 골전도성 향상을 위한 경조직 대체용 생체재료의 표면개질)

  • Kim, Sung-Wook;Lee, Woo-Kul
    • Applied Chemistry for Engineering
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    • v.16 no.6
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    • pp.725-730
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    • 2005
  • In the development of biomaterials as a substitute of hard tissues, the biocompatibility and osteoconductivity of the biomaterial are considered to be one of the most significant considerations. These biological properties of a material can be greatly improved by the modification of the surface properties by the depositing calcium phosphate thin films on the material since calcium phosphate films possess similar chemical compositions to hard tissues. The success of a material as a biomaterial will be determined by the interaction of the surface of the material with the adhesion molecules which induce cellular adhesion and biological responses of the adherent cells. Depending on the adsorption mechanisms and adsorbed conformation of the adhesion molecules on the surface of the biomaterial, cellular responses, such as adhesion, proliferation and differentiation of osteoblast cells, can be promoted or restricted. It has been reported that materials of which surfaces were modified with thin films of calcium phosphate appeared to be more osteoconductive. Rapid formations of bone nodule in addition to higher differentiations of osteoblast have been observed on the calcium phosphate thin films.

The effect of gelatin-coating on embryonic stem cells as assessed by measuring Young's modulus using an atomic force microscope

  • Hyunhee Song;Hoon Jang
    • Journal of Animal Reproduction and Biotechnology
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    • v.38 no.3
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    • pp.121-130
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    • 2023
  • Background: Coating a culture plate with molecules that aid in cell adhesion is a technique widely used to produce animal cell cultures. Extracellular matrix (ECM) is known for its efficiency in promoting adhesion, survival, and proliferation of adherent cells. Gelatin, a cost-effective type of ECM, is widely used in animal cell cultures including feeder-free embryonic stem (ES) cells. However, the optimal concentration of gelatin is a point of debate among researchers, with no studies having established the optimal gelatin concentration. Methods: In this study, we coated plastic plates with gelatin in a concentration-dependent manner and assessed Young's modulus using atomic force microscopy (AFM) to investigate the microstructure of the surface of each plastic plate. The adhesion, proliferation, and differentiation of the ESCs were compared and analyzed revealing differences in surface microstructure dependent on coating concentration. Results: According to AFM analysis, there was a clear difference in the microstructure of the surface according to the presence or absence of the gelatin coating, and it was confirmed that there was no difference at a concentration of 0.5% or more. ES cell also confirmed the difference in cell adhesion, proliferation, and differentiation according to the presence or absence of gelatin coating, and also it showed no difference over the concentration of 0.5%. Conclusions: The optimum gelatin-coating for the maintenance and differentiation of ES cells is 0.5%, and the gelatin concentration-mediated microenvironment and ES cell signaling are closely correlated.