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  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 704-709 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A study of the frequency (0.1–30 Hz) and temperature (120–373 K) behavior of the internal friction and of the dynamic modulus was carried out in polyethylene oxide (PEO)-Ba(SCN)2 polymeric electrolytes. The mechanical spectra reveal the presence of the following anelastic relaxations: (a) the γ process due to localized movements within the main chain, (b) a process due to relaxing particles introduced by salt, and (c) the αa process associated to the glass-rubber like transition. Both the γ- and αa -loss peaks are shifted to higher temperatures by the addition of salt. A careful analysis of the observed peculiarities permits us to gain an insight on the microscopic nature of the relaxation mechanisms and to associate the γ relaxation with localized segmental motion within the amorphous phase. In pure PEO and in the complex with the lowest salt content, the loss due to the melting transition of PEO crystals is also observed. The cited loss is lacking in the complexes with a salt molar fraction X〉0.05, which show an enormous enhancement of the strength of the αa relaxation. It is argued that the addition of a salt with a divalent cation to semicrystalline PEO gives rise to completely amorphous single phase structures.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    Physica C: Superconductivity and its applications 235-240 (1994), S. 3267-3268 
    ISSN: 0921-4534
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    Physica C: Superconductivity and its applications 180 (1991), S. 77-80 
    ISSN: 0921-4534
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1437-9813
    Schlagwort(e): Key words Infantile hypertrophic pyloric stenosis ; Plasmalemmal cytoskeleton ; Nitric oxide synthase ; Dystrophin ; Confocal laser scanning microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In reference to a possible neuropathy in the pathogenesis of infantile hypertrophic pyloric stenosis (IHPS), previous studies have described alterations in peptidergic transmission while others have recently attributed an important role to nitrinergic activity. Little attention has been given to the organization of the extracellular matrix (ECM) and the constituent cytoskeleton and subsarcolemma of the pyloric smooth-muscle cell. To study a possible relationship between neuronal and muscular elements in IHPS, 9 biopsies from patients with IHPS and 5 biopsies of normal pylorus were examined using immunohistochemical techniques with regard to the distribution of nerve cells and fibers (bNOS and PGP 9.5) and the ECM (laminin) and cytoskeleton (talin, vinculin, dystrophin, α-smooth iso-actin, desmin) components of the pyloric muscle. Our results showed anti-protein gene product 9.5 and b-nitric oxide synthase immunoreaction respectively reduced or absent in nerve fibers with a positive reaction inside the ganglion cells. An uneven distribution of the ECM component laminin was evident, together with a negative immunoreaction to talin and dystrophin. The imunolocalization of vinculin, α-smooth iso-actin, and desmin was similar to the controls. Our findings suggest that there is a close relationship between the nerve and muscle elements in the pathophysiology of IHPS and that non-alteration of some elements of cytoskeleton organization can play an important role in regaining pyloric function after pyloromyotomy.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1434-0879
    Schlagwort(e): Key words Adolescent varicocele ; Myofibroblasts ; Immunofluorescence ; α-Smooth muscle isoactin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Myofibroblasts of the testes play an important role in the morphofunctional integrity of the seminiferous tubule. Previous studies in adults with varicocele have demonstrated an involvement of this cell population that tends to transform into fibroblasts. The aim of the present study was to try and verify the morphological features of myofibroblasts in the adolescent with left idiophatic varicocele. Twenty-two testicular biopsies were obtained from adolescents (aged 13–18 years, mean 15.8) and operated for left idiophatic varicocele. Biopsies were processed for electron microscopy (TEM) and immunofluorescence studies. The latter determined the level of myofibroblasts by using α-smooth muscle isoactin, a specific marker of myofibroblasts and, hence, excluding fibroblasts. TEM observations revealed a normal ultrastructure of myofibroblasts that was similar to that for the controls but an increased presence of extracellular matrix. The immunofluorescence study always demonstrated strong cell positivity to anti α-smooth muscle isoactin as also seen in the controls. This study demonstrates that adolescents with varicocele have well preserved myofibroblasts and do not show any evidence of transformation into fibroblasts, this has already been demonstrated in adult varicocele. These observations could represent an important factor for the understanding of the reversal of growth failure of the testes observed after early treatment.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Journal of superconductivity 6 (1993), S. 391-395 
    ISSN: 1572-9605
    Schlagwort(e): YBCO ; dc SQUID ; high-T- c junction ; step edge junction ; Josephson effect
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Physik
    Notizen: Abstract We describe the fabrication and testing of dc SQUIDs (Superconducting QUantum Interference Devices) obtained by photolithographic patterning of YBa2Cu3O7−x thin films deposited both on SrTiO3 and MgO substrates. The Josephson junctions in the superconducting loop are of the “step-edge” type, where the weak link is obtained through the growth of grains with different orientations across suitably prepared steps previously etched on the substrate surface. TheI−V characteristics of the devices tested show multiple branches and instabilities having a weak dependence on the external magnetic field, probably due to formation of junction clusters on the substrate step. The SQUID devices showed quantum interference behavior and an easily detectable voltage modulation with the applied magnetic field at a temperature of 77 K.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Il nuovo cimento della Società Italiana di Fisica 16 (1994), S. 2095-2102 
    ISSN: 0392-6737
    Schlagwort(e): Proximity effects, tunneling phenomena, and Josephson effects ; Conference proceedings
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Summary The current status of the electronic applications of high-T c Josephson junctions is briefly reviewed. Recent results obtained by the authors on devices employing step-edge junctions are reported. In particular the design of a microwave oscillator based on a parallel array of junctions is discussed and preliminary experimental results are presented.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    International journal of infrared and millimeter waves 15 (1994), S. 723-738 
    ISSN: 1572-9559
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We measured reflectance spectra R(v) of oxygen deficient Y1Ba2Cu3O7−x (YBCO) films of different thickness, with critical temperatures between 85 and 87 K. Measurements were made at room temperature between 15 and 25000 cm−1. The measured R(v) have a maximum below 100 cm−1 and then decrease for v → 0. This low frequency behaviour of R(v) can be accounted for by considering a relevant extra-Drude contribution to the far infrared optical conductivity of YBCO.
    Materialart: Digitale Medien
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