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  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 5959-5964 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We performed isothermal annealing on a hydrogenated amorphous silicon (a-Si:H) sample deposited at low temperature in a glow discharge reactor. In order to change the hydrogen bonding configuration without affecting the silicon structure we choose a relatively low annealing temperature. We studied the dependence on the annealing time of the dark conductivity, photoconductivity, light-induced degradation of the photoconductivity, optical gap, vibrational spectra, and subgap defect density. As the annealing time increased we found an increase in the dark conductivity activation energy. This shift of the dark Fermi level toward the valence band was correlated with the growth of a peak in the density of states below midgap. From the vibrational spectra we obtained the microstructure parameter, which is indicative of the amount of hydrogen bonded as polihydrides and/or to some sort of internal surface. We used the bond-breaking model to fit photoconductivity decay as a function of illumination time, and we found a correlation between the Staebler–Wronski susceptibility and the microstructure parameter. This would mean that the stability of the material concerning light-induced degradation is related to the way hydrogen is attached in the amorphous network. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 4853-4856 
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: We describe an insert for optical and magnetic-resonance experiments on single molecules in a solid matrix at liquid-helium temperatures. The experimental arrangement allows in situ adjustment of the focusing lens and of the sample. A parabolic mirror serves to collect the fluorescence emission and to direct the light onto a photodetector. Microwaves can be irradiated through a coil around the sample while a superconducting magnet provides the possibility of a stationary magnetic field. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 99 (1995), S. 226-229 
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 99 (1995), S. 11644-11649 
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
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  • 5
    ISSN: 0942-0940
    Schlagwort(e): Calcitonin gene-related peptide ; CGRP ; subarachnoid haemorrhage ; SAH ; transcranial Doppler ; trigemino-cerebrovascular system
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A possible involvement of perivascular vasodilatory neuropeptides in subarachnoid haemorrhage (SAH) has been evaluated in man by measuring the levels of calcitonin gene related peptide (CGRP)-, substance P (SP)- and vasoactive intestinal peptide (VIP)-like immunoreactivity (LI) in the cranial venous outflow and in CSF in 34 patients admitted to the hospital after an acute SAH. After operation with aneurysm clipping and nimodipine treatment, blood samples were taken from the external jugular vein (EJV) or cerebrospinal fluid (CSF) and analysed for neuropeptide levels with specific radioimmuno assays (RIA) during the postoperative course. The degree of vasoconstriction in the patients was monitored with Doppler ultrasound recordings bilaterally from the middle cerebral (MCA) and internal carotid arteries (ICA) following the EJV blood sampling every second day. The mean value of all CGRP-LI measurements in EJV during the entire course of SAH (n=20) revealed a significantly higher level as compared to controls. The highest CGRP-LI levels were found in patients with the highest velocity index values (vasospasm). The relationship Vmean MCA/Vmean ICA was used as an index of vasoconstriction. In patients with MCA aneurysms (n=10), a significant correlation (r=0.65, p〈0.05) was found between the vasospasm index and CGRP-LI levels. There were no changes observed in the SP- and VIP-LI levels. Alterations in cerebrovascular tone induced by changing arterial CO2 tension or lowering of blood pressure (ketanserin infusion test) did not alter the levels of the perivascular peptides in the EJV. In addition, CGRP-, SP-, VIP- and neuropeptide Y (NPY)-LI were analysed in CSF in the post-operative course after subarachnoid haemorrhage (SAH) in 14 patients. The CSF VIP-LI was lower in SAH than in control (p〈0.05). The CGRP-LI level was measurable in SAH CSF but not in CSF of controls. In individual patients with marked vasoconstriction increased levels of CGRP-LI (up to 14 pmol/L) and NPY-LI (up to 232 pmol/L) were observed. The results of this study are in support of our hypothesis that there is an involvement of the sensory peptide CGRP in a dynamic reflex aimed at counterbalancing vasoconstriction in SAH.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Annales geophysicae 13 (1995), S. 475-493 
    ISSN: 0992-7689
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract This work follows the paper titled “Spatial transport and spectral transfer of solar wind turbulence composed of Alfvén waves and convective structures I: The theoretical model”, and deals with the detailed physics and numerical solution of a two-component solar wind model, consisting of small-scale Alfvén waves and convected structures. In particular, we present numerical results which qualitatively reflect many of the observed features of the radial and spectral evolution of the turbulent energies, the residual energy, the cross-helicity and Alfvén-ratio in high-speed solar wind streams. These features are the following: the formation of a characteristic “inclined eye”, which evolves between the energy spectra displayed over the frequency axis and tends to close in the radial development of the spectra, a steepening of all spectra towards Kolmogorov-like f-5/3 spectra, the development of the normalized cross-helicity towards a constant not much less than one and the formation of a “trough” form of the Alfvén ratio with a z-shaped left boundary, By weighting special terms in the equations differently, we can also cast light on the physical role of parametric conversion model terms, wave-structure scattering model terms, nonlinear terms, spherical expansion terms and their effects on the radial evolution of turbulent energies in high-speed solar wind streams.
    Materialart: Digitale Medien
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  • 7
    ISSN: 0992-7689
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract In this paper we give a survey of detailed algebraic developments of a solar wind turbulence model. The numerical solution of the coupled system of spectral transfer equations for turbulence composed of Alfvén waves and convective structures or two-dimensional turbulence is prepared. The underlying theory of spectral transfer equations was established by several authors in the early 1990s. The related numerical turbulence model which is elaborated in detail in this paper is based on a rotationally symmetric solar wind model for the background magnetic and flow velocity fields with the full geometry of Parker’s spiral which has to be inserted into the transfer equations. Various sources and sinks for turbulent energy are included and appropriately modelled analytically. Spherical expansion terms related to radial gradients of the background velocity fields are considered as far as possible within a rotational symmetric solar wind model, which excludes vorticity effects. Furthermore, nonlinear interaction terms are considered, justified by phenomenological arguments and evaluated by dimensional analysis. Moreover, parametric conversion terms for Alfvén waves and wave-structure interactions are modelled and a generalized spectral flux function for the residual energy eR is introduced. In addition, we compensate the spectra for WKB trends and f-5/3-slopes in order to prepare a convenient form of the equations for numerical treatment. The modelling of source and sink terms includes a special analytical treatment for correlation tensors. This first part presents a summary of the main ideas and the special approximations used for all these terms, together with details on the basic steps of the algebraic calculations. The description of the numerical scheme and a survey of the numerical results of our model, as well as a discussion of the main physical results are contained in a companion paper.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Abdominal imaging 20 (1995), S. 176-178 
    ISSN: 1432-0509
    Schlagwort(e): Magnetic resonance imaging ; Neurofibroma ; Prostate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Pelvic neurofibromatosis is a rare disease and rarely involves the prostate. A 19-year-old male presented with irritative and obstructive voiding symptoms. Magnetic resonance imaging showed a large mass extending from the sacral promontory to the perirectal and perivesical spaces and to the proximal root of the penis. The mass also involved the prostate. The characteristics of the mass were highly suggestive for neurofibroma. Prostate biopsy showed neurofibroma, and the immunohistochemistry stain for S-100 protein was positive.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical microbiology & infectious diseases 14 (1995), S. 137-140 
    ISSN: 1435-4373
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Seventy-seven clinical isolates ofXanthomonas maltophilia (Stenotrophomonas maltophilia) were consecutively collected from the Rigshospitalet, Copenhagen, ribotyped and compared with the ribotypes of 25 other clinical and reference strains ofXanthomonas maltophilia. Using restriction enzymeEcoRI, 20 different ribotypes were observed, with 78 isolates displaying the five most common types. Using another enzyme,BamHI, these 78 isolates were further subdivided into 16 different ribotypes. Three patients harboured two strains with different ribotypes. No type was found related to only one department and no single-strain outbreak was detected. The origin of this wealth of different strains in hospital patients needs to be established.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Archives of orthopaedic and trauma surgery 114 (1995), S. 226-228 
    ISSN: 1434-3916
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In recent years the problem of deep venous thrombosis (DVT) in outpatients and discharged patients has grown into a medical and juridical problem. In traumatology certain recommendations and statistical material exist: similar recommendations were made by the Berufsverband der Ärzte für Orthopädie, Germany, pointing out the lack of sufficient statistical material. With the present study we tried to evalaute the actual management of DVT in discharged patients or outpatients in leading orthopaedic hospitals. The results from December 1993 reveal an inhomogenous procedure which does not precisely follow the above recommendations. However, most orthopaedic surgeons agree that either general or individual means to prevent DVT should be available for ambulatory and discharged patients with plaster immobilisation of the leg according to presently accepted standards, i.e. low-dose heparin or low-molecular-weight heparins. Reduced weight-bearing, in contrast, is considered not to require preventive heparinisation to any great extent.
    Materialart: Digitale Medien
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