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  • 1
    Electronic Resource
    Electronic Resource
    Synthesis and thermal properties of block copolyetheresters with poly(pentamethylene p,p′-bibenzoate) segments (1995)
    Springer
    Journal of polymer research 2 (1995), S. 109-114 
    Details
    ISSN: 1572-8935
    Keywords: Thermotropic ; Liquid crystalline polymers ; Smectic ; Block copolyetheresters ; Thermal transitions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The block copolyetheresters with hard segments of poly(pentamethylene p,p′-bibenzoate) and soft segments of poly (tetramethylene ether) were prepared by melt polycondensation of dimethyl-p,p′-bibenzoate, 1,5-pentanediol and poly (tetramethyene ether) glycol (PTMEG) with molecular weights of 650, 1000 and 2000. The results by NMR indicate that the polymer composition is determined by the charge molar ratio (x) of PTMEG to dimethyl-p,p′-bibenzoate. The thermal transitions of the block copolyetheresters were investigated by DSC in combination with X-ray diffraction and polarized microscopy. Some block copolyetheresters exhibit a monotropic smectic phase due to the presence of the poly (pentamethylene p,p′-bibenzoate) segments. As the molar content of PTMEG increases, the average sequence length of the polyester segments decreases, the isotropic-smectic transition temperature and the smectic order decrease accordingly. When x is as high as 0.3, the block copolyetheresters exhibit no liquid crystallinity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01493210
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  • 2
    Electronic Resource
    Electronic Resource
    Intermolecular interaction and conformation in poly(ether ether ketone)/poly(ether imide) blends — An infrared spectroscopic investigation (1996)
    Springer
    Journal of polymer research 3 (1996), S. 151-158 
    Details
    ISSN: 1572-8935
    Keywords: Blends ; PEEK ; PEI ; Infrared spectroscopy ; Conformation ; Intermolecular interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The intermolecular interaction and the conformation in miscible blends of poly(ether ether ketone) (PEEK) and poly(ether imide) (PEI) have been investigated by Fourier-transform infrared (FTIR) spectroscopy. The intensity of the C=O out-of-phase stretching (1725 cm−1) of PEI shows a minimum at 70 wt% PEI, whereas that of the C=O in-phase stretching (1778 cm−1) is not perturbed by blending. These intensity variations have been attributed to the effect of blending on the coplanarity of the two imide rings bridged by the phenylene group. Change in coplanarity of these two imide rings alters the intensity of the C=O out-of-phase stretching, but it can not affect the intensity of the C=O in-phase stretching. When the two imide rings are perpendicular to each other, the intensity of the C=O out-of-phase stretching is shown to reach the minimum, corresponding to the observation at 70 wt% PEI. The difference spectra (blend - PEEK - PEI) reveal that the bands associated with the diphenyl ether groups in PEEK are modified by blending with PEI. It is proposed that the favorable interaction takes place between the oxygen lone-pair electrons of the ether group in PEEK and the electron-deficient imide rings in PEI.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01494524
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  • 3
    Electronic Resource
    Electronic Resource
    Inhibition of cancer cell motility and invasion by interleukin-12 (1995)
    Springer
    Clinical & experimental metastasis 13 (1995), S. 396-404 
    Details
    ISSN: 1573-7276
    Keywords: cell motility ; colon cancer ; interleukin-12 ; invasion ; metastasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Tumour cell motility and attachment are crucial requirements in the formation of metastatic lesions. These properties are affected by a number of cytokines including hepatocyte growth factor/scatter factor (HGF/SF) and several immunoregulatory proteins, including interleukin-12 (IL-12). Although IL-12 has been reported to exhibit potent anti-tumour effects in vivo, a direct effect of IL-12 on cancer cells has not been reported. We show here that IL-12 directly inhibited the attachment of the human colon cancer cell lines HRT18, HT29 and HT115 to Matrigel, HGF/SF-stimulated cell motility and HGF/SF-induced cell invasion through a reconstituted basement membrane. IL-12 did not affect the growth of these cell lines. Flow cytometry, Western analysis and immunohistochemistry revealed an up-regulation of E-cadherin cell-surface adhesion molecules. These direct effects of IL-12 on colon cancer cells suggest a potentially important role for IL-12 in metastasis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00121916
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  • 4
    Electronic Resource
    Electronic Resource
    Regulation of desmosomal cell adhesion in human tumour cells by polyunsaturated fatty acids (1997)
    Springer
    Clinical & experimental metastasis 15 (1997), S. 593-602 
    Details
    ISSN: 1573-7276
    Keywords: cell adhesion ; desmoglein ; E-cadherin ; gamma linolenic acid ; invasion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Desmosomes are key structures in cell-cell adhesion. In this study we examined the effect of n-6 essential fatty acids on the expression of desmoglein (Dsg), desmosomal cadherin and the formation of desmosomes in E-cadherin negative human breast, colon and lung cancer cells and melanoma cells. Electron microscopy revealed that cells cultured with gamma linolenic acid (GLA) showed increased cell-cell adhesion together with an increase in the formation of desmoglein-containing desmosomes. Western blotting studies of cellular proteins demonstrated that, following culture with fatty acids, Dsg expression was modified, with the greatest increase seen after GLA treatment. Other fatty acids increased Dsg expression, but to a lesser extent. It is concluded that GLA regulates desmosome-mediated cell-cell adhesion in human cancer cells, particularly in cells without E-cadherin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018435229087
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    Paper (German National Licenses)
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