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  • 1
    Electronic Resource
    Electronic Resource
    Experimente zur Supraleitung in dem System Niob-Zinn und der Mischkristallreihe Nb3Sn-Ta3Sn (1961)
    Springer
    The European physical journal 162 (1961), S. 275-289 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Zusammenfassung In the intermetallic system Nb-Sn the compound Nb3Sn with a superconducting temperature of 18° K is obtained by sintering techniques even with strong deviation from stoichiometric composition of the samples. A possible incorporation of the excess elements into the Nb3Sn-lattice is manifested only by very minute changes of the critical temperature. A small atomic percentage of niobium-excess causes a maximum of the critical temperature. The critical temperature of mixed crystals of Nb3Sn and Ta3Sn changes almost linearly with composition. This system seems to have some interest concerning theoretical aspects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01341976
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Quantitative data on the fine structural organization of the palisade zone of the median eminence (1973)
    Springer
    Cell & tissue research 136 (1973), S. 111-120 
    Details
    ISSN: 1432-0878
    Keywords: Median eminence ; Rat ; Granular vesicles ; Ultrastructure ; Quantitative evaluation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In order to characterize different sub-zones in the palisade zone of the rat median eminence, quantitative ultrastructural parameters were applied to brains fixed in aldehyde-osmium tetroxide. The palisade zone has been subdivided in 4 successive sub-zones. Increasing numbers of granular vesicles (GV), especially those smaller than 110 nm, are observed from dorsal to ventral sub-zones. There also are more GV per unit area of nervous tissue in the perivascular than in the more dorsal sub-zones. The individual nerve profiles exhibit a larger size in the perivascular layer than in the more dorsal areas, whereas the number and size of nerve profiles devoid of vesicles diminish from dorsal to ventral. As a consequence more GV occur in the perivascular nerve profiles. In the GV containing nerve profiles the concentration of GV is, however, constant in the different sub-zones. A fluctuating size of the preterminal and terminal parts of the nerve fibres is suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307683
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  • 3
    Electronic Resource
    Electronic Resource
    Sizes of granular vesicles in the rat median eminence, with special reference to the zona granulosa (1973)
    Springer
    Cell & tissue research 146 (1973), S. 501-515 
    Details
    ISSN: 1432-0878
    Keywords: Median eminence (Rat) ; Granular vesicles ; Ultrastructure ; Quantitative evaluation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A quantitative evaluation has been made of the sizes of neuronal granular vesicles (GV) in different (sub-)zones of the rat median eminence. On the basis of the frequency distribution of the mean sizes of the GV in the individual nerve profiles, at least 4 tentative categories of nerve profiles may be distinguished. However, available data do not permit characterization of nerve fibre categories in terms of neurohormone and/or neurotransmitter storage. From dorsal to ventral the palisade zone shows a decrease in mean size of GV; furthermore, the relative number of nerve profiles characterized by small GV (mean size smaller than 112 nm) increases. In contrast, the GV in the zona granulosa, that part of the external zone of the median eminence ventral to the palisade zone, are of relatively large size. Qualitative observations indicate that the zona granulosa may be regarded as an area for both storage and release of biologically active substances.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02347179
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  • 4
    Electronic Resource
    Electronic Resource
    Influence of castration on incorporation of exogenous peroxidase into “synaptic” vesicles of the median eminence (1975)
    Springer
    Cell & tissue research 159 (1975), S. 11-21 
    Details
    ISSN: 1432-0878
    Keywords: Median eminence ; Agranular and granular vesicles ; Horseradish peroxidase ; Castration ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the median eminence of male rats, nerve profiles in the immediate vicinity of portal capillaries have been divided into 4 categories on the basis of their vesicular content: profiles a with agranular “synaptic” vesicles of about 50 nm, b with similar agranular vesicles and also with granular vesicles of mainly 60–140 nm, c with granular vesicles alone and d without vesicles. Twenty-four hours after castration, the percentage of profiles of category a was significantly increased when compared with sham-operated animals, whereas the percentage of profiles of category b was significantly decreased. After intravenous injection of exogenous peroxidase, especially the nerve profiles located in direct contact with the outer basement membrane of the portal capillaries contained peroxidase positive “synaptic” vesicles. Injection off peroxidase after castration resulted in a significant increase in the percentage of nerve profiles containing both peroxidase positive and peroxidase negative “synaptic” vesicles (category a). It is suggested that, in certain nerve terminals, castration may lead to release off the content of granular vesicles, which may contain gonadotropin releasing factor. This release then may cause that nerve terminals with both agranular vesicles and granular vesicles (category b) change in their vesicular content and are therefore classified as terminals with only agranular vesicles (category a). An increased turnover rate in the ultrastructurally affected terminals may be reflected in increased uptake of exogenous peroxidase. The observations imply that certain neurones projecting to portal capillaries in the median eminence are, directly or indirectly, sensitive to changes in the level of gonadal steroids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231991
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  • 5
    Electronic Resource
    Electronic Resource
    Synaptic changes in the terminals of rod photoreceptors of albino mice after partial visual cell loss induced by brief exposure to constant light (1987)
    Springer
    Cell & tissue research 250 (1987), S. 43-52 
    Details
    ISSN: 1432-0878
    Keywords: Retina ; Light damage ; Photoreceptors ; Synaptic growth ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Albino mice were exposed to constant light for 7 days and were then transferred to periodic light. After initial photic damage and partial cell loss, the remaining visual cells recovered and survived as a stable population. Regions of the outer nuclear layer containing 4–6 rows of nuclei were more affected than those containing 6–10 rows. Changes in the synaptic structures in the receptor terminals of these two regions were recorded after varying survival periods. Some of the rod terminals had multiple synaptic ribbons and larger numbers of horizontal cell processes and bipolar cell dendrites. The number of terminals with multiple ribbons increased during recovery in periodic light. Morphometry demonstrated that the perimeters of horizontal and bipolar cell processes within the rod terminals were significantly larger than those in age-matched control mice, especially 4 weeks after recovery; they remained significantly larger than controls after 2 and 3 months. We suggest that partial loss of rod cells within a group of cells that are synaptically related to a common bipolar or horizontal cell results in synaptic growth inside the terminals of the surviving cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214652
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  • 6
    Electronic Resource
    Electronic Resource
    Ultrastructural evidence for exocytosis in the median eminence of the rat (1972)
    Springer
    Cell & tissue research 131 (1972), S. 99-107 
    Details
    ISSN: 1432-0878
    Keywords: Median eminence ; Rat ; Exocytosis ; Micro-pinocytosis ; Releasing factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Exocytosis has been demonstrated by electron microscopy in the external zone of the median eminence of the rat. Exocytotic profiles have been observed in nerve fibres characterized by the presence of granular vesicles with median diameters of 90–103 nm and agranular vesicles of about 50 nm. In addition to the small agranular vesicles, coated vesicles of the same size have been found in many nerve fibres, suggesting that at least part of the agranular vesicles in the median eminence originate by micro-pinocytosis. The nature of the fibres showing exocytosis is discussed. Attention is drawn to the possibility of identifying types of fibres in the median eminence by the occurrence of exocytosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307203
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  • 7
    Electronic Resource
    Electronic Resource
    Influence of castration on incorporation of exogenous peroxidase into “synaptic” vesicles of the median eminence (1974)
    Springer
    Cell & tissue research 155 (1974), S. 1-11 
    Details
    ISSN: 1432-0878
    Keywords: Median eminence ; Agranular and granular vesicles ; Horseradish peroxidase ; Micro-pinocytosis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Nerve profiles in the basal part of the palisade zone of rat median eminence have been divided into 4 categories on the basis of their vesicular content: profiles a with agranular vesicles of about 50 nm, b with similar agranular vesicles and also with granular vesicles of mainly 70–140 nm, c with granular vesicles alone and d without vesicles. After intravenous injection of exogenous peroxidase, castrated male rats showed, in comparison to sham-operated controls, a 3–5 fold increase in the percentage of nerve profiles of category a which contained peroxidase loaded vesicles of about 50 nm. In contrast, no significant change was observed for nerve profiles of other categories. It is concluded that exogenous peroxidase may be used to demonstrate changes in the activity of tuberoinfundibular nerve terminals at the ultrastructural level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220280
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