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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
    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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  • 3
    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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  • 4
    Electronic Resource
    Electronic Resource
    Calorimetric characterization of the formation of acrylic type bone cements (1996)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 33 (1996), S. 83-88 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The formation of acrylic bone cements upon heating was investigated by differential scanning calorimetry (DSC). The effects of the contents of initiators, accelerator, biocompatibilizer, and crosslinking agents on the rate and the heat of polymerization during DSC heating were studied. The rate and the heat of polymerization (ΔH) were characterized by the peak temperature and the area of the DSC exotherm, respectively. It was found that both the rate and heat of polymerization decreased with increasing heating rate. The ΔH was increased considerably with increasing benzoyl peroxide (BPO) initiator concentration from 1 to 10% (w/v), whereas the rate of polymerization was reduced significantly. An increase in azobisisobutyronitrile (AIBN) initiator concentration also induced an increase in ΔH, but the rate of reaction was not affected considerably. The addition of the accelerator promoted the rate of reaction but resulted in a drop in ΔH. The rate of polymerization for the system containing BPO initiator was increased quite significantly with the addition of hydroxyethyl methacrylate (HEMA) biocompatibilizer, while the ΔH was slightly increased. For the system using AIBN as the initiator, the rate of polymerization was decreased slightly and the ΔH dropped significantly with the addition of HEMA. The effect of ethylene glycol dimethacrylate (EGDMA) crosslinking agent was also examined. Polymerization became more rapid with the addition of EGDMA in the bone cement using BPO as the initiator, while it remained approximately constant for the system using AIBN as the initiator. No systematic change in ΔH was observed with the addition of EGDMA in both systems. This study demonstrated that DSC is a potential tool to measure the amount of heat released and also the rate of polymerization for bone cements. © 1996 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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