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  • 1
    Electronic Resource
    Electronic Resource
    Effect of molecular weight on two smectic polyesters (1996)
    Springer
    Journal of polymer research 3 (1996), S. 59-63 
    Details
    ISSN: 1572-8935
    Keywords: Thermotropic ; Liquid crystalline polymers ; Smectic ; Intrinsic viscosity ; 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 liquid crystalline transitions of two kinds of smectic polyesters with different molecular weights were investigated by DSC, polarized microscopy and X-ray diffraction. The molecular weight affects the transitions significantly for these two kinds of polyesters. With a high enough molecular weight, both poly (pentamethylenep,p′-bibenzoate) and poly(hexamethylenep,p′-bibenzoate) exhibit an enantiotropic smectic phase, but the two endothermic transition peaks of the DSC heating curve seem to overlap. The polyesters tend to exhibit a monotropic smectic phase as the molecular weight decreases. From the DSC cooling curve, the isotropic-smectic transition can be seen more clearly. As the molecular weight decreases, the smectic order decrease significantly. The molecular weight affects the transitions in a different way for these two different kinds of polyesters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01493381
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  • 2
    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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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Intraepidermal nerve fiber expression of calcitonin gene-related peptide, vasoactive intestinal peptide and substance P in psoriasis (1997)
    Springer
    Archives of dermatological research 289 (1997), S. 611-616 
    Details
    ISSN: 1432-069X
    Keywords: Key words Neuropeptides ; Psoriasis ; Substance P ; Vasoactive intestinal peptide ; Calcitonin-gene-related protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In order to evaluate more fully the role of neuropeptides in the pathogenesis of psoriasis, skin biopsies were obtained from 36 patients with psoriasis to identify substance P (SP), vasoactive intestinal peptide (VIP) and calcitonin gene-related peptide (CGRP). Lesional and nonlesional skin was examined from these biopsies and the results compared with those from biopsies taken from patients with a variety of other inflammatory dermatoses, including lichen planus, lichen simplex chronicus, spongiotic dermatitis, and seborrheic dermatitis. Also studied was a series of nine biopsies taken from patients with no known skin disorders. We found an increase in the number of SP-positive nerve fibers within the epidermis in biopsies from lesional skin of psoriasis patients (8.4 nerves per 3-mm biopsy) compared with nonlesional psoriatic skin (2.6 nerves per 3-mm biopsy) and normal skin (2.0 nerves per 3 mm biopsy). Other inflammatory disorders also demonstrated fewer SP-positive nerves than lesional psoriatic skin; lichen planus (0 nerves per 3 mm biopsy) and lichen simplex chronicus (1.3 nerves per 3 mm biopsy). The difference in SP-positive nerve expression between lesional psoriatic skin and the group comprising nonlesional skin, normal skin, lichen planus, and lichen simplex chronicus attained statistical significance ( P 〈 0.013). SP-positive intraepidermal nerve fibers in lesional psoriatic specimens were fewer than in spongiotic dermatitis (17.4 nerves per 3 mm biopsy). There was no significant difference in numbers of VIP- or CGRP-immunopositive intraepidermal nerve fibers between psoriatic skin and the group comprising all other material tested. However, in five patients with psoriasis, there was a marked increase in the expression of intraepidermal CGRP (up to 10.7 nerves per 3-mm biopsy) and VIP (up to 8.3 nerves per 3-mm biopsy) which was not observed in control groups. These findings suggest that neuropeptides SP, CGRP, and VIP play a role in the pathogenesis of psoriasis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004030050249
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  • 4
    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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    Paper (German National Licenses)
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  • 5
    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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