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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 60 (1963), S. 815-825 
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The synaptolemma of axo-dendritic synapses in the rabbit striate and peristriate cortex has been examined in the electron microscope. Observations are reported of 1) a subsynaptic organelle, in the juxta-membranous part of the dendrite cytoplasm; 2) a typical attenuation of the synaptic cleft, located at the circumference or at the center of the synaptolemma; 3) interlemmal elements of two types, designated A and B. The possible functional implications of the findings are discussed in the light of present-day knowledge of synaptic transmission.
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  • 2
    ISSN: 1614-7456
    Keywords: Rehabilitation ; Robotics ; User interface ; Simulation ; Haptics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Advances in software, computing, control architectures, and design practice have led to rehabilitation robots with high-bandwidth, bidirectional user interfaces that allow people to interact with mechatronic systems in highly realistic, cognitively and biomechanically coupled scenarios. Immersive and graphic interfaces to real-time systems such as robots require, robust control environments and high-speed computing to provide safe, human-scale motions and interfaces with sufficient quality to be usable in functional environments. This paper illustrates some emerging applications in rehabilitation, spanning assistive technology, simulation/design aids, and smart therapy devices. Examples will be drawn laregly from work done at the VA Palo Alto Rehabilitation R&D Center.
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  • 3
    ISSN: 0044-2313
    Keywords: Bis[triglymesodium(1+)][Tetrakis(borane)sulfate(2-)], [Na · Triglyme]2[S(BH3)4] ; preparation ; crystal structure ; SCF calculations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: [Na · Triglyme]2[S(BH3)4]: a Salt of the New Anion Tetrakis(borane)sulfate(2- ). Crystal Structure and Theoretical Investigation of the StructureNa[H3B-m̈2-S(B2H5)] 1 is produced by the reaction between NaSH and THF · BH3, under dehydrogenation. 1 is also formed as the first 11B-NMR-spectroscopically detectable reaction product by the reaction between anhydrous Na2S and THF · BH3. Adducts of BH3 with the S2- ion are not detectable in THF. The anion [S(BH3)4]2- can however be obtained, by the addition of NaBH4 to 1 in diglyme or triglyme respectively: [Na  -  Triglyme]2[S(BH3)4] 2. 2 crystallizes in the monoclinic space group P21/n (Nr. 14). Structural data of 1 and 2 have been calculated by SCF methods. The anion of 2 may be viewed either as an adduct of B2H6 with S2-, or as a bridge substituted thia derivative of B2H7-; furthermore the anion of 2 is isoelectronic and isostructural with the SO42- ion.
    Notes: Bei der Reaktion zwischen NaSH und THF · BH3 entsteht unter H2-Abspaltung Na[H3B-m̈2-S(B2H5)] 1. 1 entsteht auch als erstes 11B-NMR-spektroskopisch nachweisbares Reaktionsprodukt bei der Reaktion zwischen wasserfreiem Na2S und THF · BH3. Addukte von BH3 an das S2--Ion lassen sich in THF als Lösungsmittel nicht nachweisen. Das neue Anion [S(BH3)4]2- kann jedoch durch Addition von NaBH4 an 1 in Diglyme bzw. Triglyme erhalten werden: [Na · L]2[S(BH3)4] 2. 2 kristallisiert monoklin in der Raumgruppe P21/n (Nr. 14). Aus SCF-Rechnungen erhielten wir die Strukturparameter für 1 und 2. Das Anion von 2 kann sowohl als Addukt von B2H6 an S2- als auch als brückensubstituiertes Thia-Derivat des B2H7--Ions aufgefaßt werden; ferner ist es isoelektronisch und isostrukturell mit dem SO42-- Ion.
    Additional Material: 5 Ill.
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  • 4
    ISSN: 1434-4726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung Das Krankheitsbild der “Glossitis rhombica mediana” war, obwohl keineswegs selten, hinsichtlichUrsache und Wesen bis heute ungeklärt; sie wurde als chronische Entzündung aufgefaßt und vielfach ohne sichere Anhaltspunkte mit Lues, Tuberkulose und verschiedenen anderen Erkrankungen in Zusammenhang gebracht. Eine Reihe eigener Beobachtungen weisen nach, daß dieser Erkrankungfehlerhafte, überschüssige Gefäßbildungen nach Art der Angiome bzw. Gefäßnävi zugrunde liegen. DieLokalisation der Erkrankung im Bereiche derembryonalen Anlage des Tuberculum impar an der Zunge läßt sie in die Gruppe derfissuralen Angiome einreihen. Befunde chronischer Entzündung sowie Veränderungen im Epithel werden sekundär durch chronische Reize fehlerhaften und funktionell minderwertigen Gewebes erklärt.
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  • 5
    ISSN: 1573-7381
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cobalt-labelled motoneuron dendrites of the frog spinal cord at the level of the second spinal nerve were photographed in the electron microscope from long series of ultrathin sections. Three-dimensional computer reconstructions of 120 dendrite segments were analysed. The samples were taken from two locations: proximal to cell body and distal, as defined in a transverse plane of the spinal cord. The dendrites showed highly irregular outlines with many 1–2 μm-long ‘thorns’ (on average 8.5 thorns per 100 μm2 of dendritic area). Taken together, the reconstructed dendrite segments from the proximal sites had a total length of about 250 μm; those from the distal locations, 180 μm. On all segments together there were 699 synapses. Nine percent of the synapses were on thorns, and many more close to their base on the dendritic shaft. The synapses were classified in four groups. One third of the synapses were asymmetric with spherical vesicles; one half were symmetric with spherical vesicles; and one tenth were symmetric with flattened vesicles. A fourth, small class of asymmetric synapses had dense-core vesicles. The area of the active zones was large for the asymmetric synapses (median value 0.20 μm2), and small for the symmetric ones (median value 0.10 μm2), and the difference was significant. On average, the areas of the active zones of the synapses on thin dendrites were larger than those of synapses on large calibre dendrites. About every 4 μm2 of dendritic area received one contact. There was a significant difference between the areas of the active zones of the synapses at the two locations. Moreover, the number per unit dendritic length was correlated with dendrite calibre. On average, the active zones covered more than 4% of the dendritic area; this value for thin dendrites was about twice as large as that of large calibre dendrites. We suggest that the larger active zones and the larger synaptic coverage of the thin dendrites compensate for the longer electrotonic distance of these synapses from the soma.
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  • 6
    ISSN: 0044-2313
    Keywords: [Disodium(2 +)][1,2-Diselena-diboranate(2 -)] ; [Tetraphenylphosphonium(1 +)][μ2-Selena-(diboranyl)boranate(1 -)] ; preparation ; SCF calculations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Vibrational Spectroscopic Investigation of [H3B—Se—Se—BH3]2- and [H3B-μ2-Se(B2H5)]- Crystal Structure and Theoretical Investigation of the Molecular Structure of [H3B-μ2-Se(B2H5)]-M2[H3B—Se—Se—BH3] 1 is produced by the reaction between elemental selenium and MBH4 (1 : 1) in triglyme (diglyme), under dehydrogenation. 1 reacts with an excess of B2H6 to give M[H3B-μ2-Se(B2H5)] 2 which is also formed in the reaction of THF · BH3 with 1. These reactions proceed under cleavage of the Se—Se bond and hydrogen evolution. [(C6H5)4]Br reacts with Na · 2 to form [(C6H5)4P] · 2 which crystallizes in the tetragonal space group I4 (Nr. 82). An X-ray structure determination failed because of disordering of the cation and anion. 11B, 77Se NMR shifts and 1J(11B1H) coupling constants as well as IR- and Raman spectroscopic investigations convey further structural information. Structural data of 2 have been calculated by SCF methods. The anion of 2 may be viewed either as an adduct of Se with B3H8-, or as a bridge substituted selena derivative of B2H6.
    Notes: Bei der Reaktion zwischen elementarem Selen und MBH4 (1 : 1) (M = Na, Li) in Triglyme (Diglyme) entsteht unter Wasserstoffabspaltung M2[H3B—Se—Se—BH3] 1. Bei der Behandlung von 1 mit überschüssigem B2H6 oder THF · BH3 wird die Se—Se-Bindung gespalten und es entsteht unter erneuter Wasserstoffabspaltung M[H3B-μ2-Se(B2H5)] 2. Aus Na · 2 und [(C6H5)4P]Br entsteht [(C6H5)4P] · 2, welches tetragonal in der Raumgruppe I4 (Nr. 82) kristallisiert. Kation und Anion sind im Kristall fehlgeordnet. Strukturinformationen konnten aus den 11B-, 77Se- und 1J(11B1H)-Daten einerseits und den IR- und Raman-spektroskopischen Untersuchungen andererseits erhalten werden. Aus SCF-Rechnungen erhielten wir die Strukturparameter für das Anion 2. 2 kann sowohl als Addukt von Se an B3H8- als auch als brückensubstituiertes Selena-Derivat des B2H6 aufgefaßt werden.
    Additional Material: 3 Ill.
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  • 7
    ISSN: 1432-1106
    Keywords: Mouse barrelfield ; Somatosensory system ; Dendrite orientation ; Cortical plasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary There is a statistically significant order in the tangential orientation of stellate cell dendrites, both spiny and smooth, in layer IV of the barrelfield of the mouse parietal cortex. Neurones situated in a barrel side have most of their dendrites oriented towards the barrel hollow; those situated in the hollow preferentially orient their dendrites parallel to the long axis of the barrel. A quantitative measure of the orientation of individual dendrites in barrelfields of 60-day old mice was obtained using a semiautomatic computer-microscope and a minicomputer. In the same manner, the dendrite orientation of layer IV stellate cells was determined in barrelfields, whose (cytoarchitectonic) pattern had been experimentally altered through lesions of the middle row of the mystacial vibrissal follicles at birth. The dendrites of these cells are oriented in harmony with the novel parcellation of the cortex. Consequently, for cells in the altered areas of the barrelfields, the dendrite orientation is different from that of cells with identical positions in a normal field (see Fig. 8). We tentatively interpret these findings as an adaptation of dendrite orientation to an altered pattern of thalamic input to layer IV that, in turn, is a consequence of the peripheral manipulation.
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  • 8
    ISSN: 1432-1106
    Keywords: Barrel ; Barreloid ; Thalamus ; Somatosensory system ; Mouse ; Phaseolus vulgaris ; HRP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to elucidate the geometric organization of projections from the barrel cortex to the thalamus, iontophoretic injections of the anterograde tracer Phaseolus vulgaris-leucoagglutinin were made. The injections were confined to one barrel column (i.e. barrel in layer IV + cortical tissue above and below it). Axonal terminations could be demonstrated in three thalamic nuclei: reticularis (RT), ventrobasalis (VB) and posterior (PO). Anterograde terminal labelling was obtained in RT + VB; in PO only; or in RT + VB + PO. The terminals labelled in PO were much larger than those in RT and VB. The termination areas in RT, VB and PO were shaped like rods which have a rostro-caudal orientation. These cortico-thalamic projections are discretely and topographically organized. The clearest such arrangement was found in VB. Here, projections from the A row of barrels in BF terminate dorsally, whereas those from the C row end ventrally. Barrel A1 projects to the lateral part of VB, whereas A4, to more medial parts; other rows are arranged similarly. These results were compared with the distribution of thalamo-cortical projection neurons that were labelled after iontophoretic HRP injections in individual barrels. We concluded that the corticothalamic projections originating from one barrel column contact an arc of barreloids in VB.
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  • 9
    ISSN: 1432-1106
    Keywords: Barrel ; Mouse somatosensory system ; Phaseolus vulgaris-leucoagglutinin ; Cortical efferents ; Trigeminal nuclei
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to analyze the organization of the efferent projections of single barrel columns (BC, i.e. a barrel in layer IV of parietal cortex plus the cortical tissue above and below it), we made small iontophoretic injections of the anterograde tracer Phaseolus vulgaris leucoagglutinin in the barrel cortex of 20 adult mice. On the basis of reconstructions of the sites of terminal labelling, the brain regions receiving projections from the barrel cortex could be identified and classified in five groups. Each group is characterized by the topography of the distribution of efferents arising from a single BC. The projections to the trigeminal sensory complex are point to point: i.e. one BC projects only to the site of termination of the primary sensory neurons innervating the corresponding whisker follicle. In the ventrobasal thalamic nucleus BC projections are not restricted to the corresponding barreloid; instead they contact parts of barreloids belonging to one arc. In the reticular and posterior thalamic nuclei the projections from a row of BC's converge to a collective termination site, whereas in the superior colliculus the projections from an arc of BC's converge to a common termination site. There is a complete overlap of BC projections in restricted zones within SII, motor cortex, perirhinal cortex, contralateral barrelfield, caudoputamen and pons. The organization of the efferents from the barrel cortex demonstrates a contrast between feedback and feedforward projections from this important area of neocortex.
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  • 10
    ISSN: 1432-1106
    Keywords: Barrel cortex ; GAD-immunoreactivity ; Adult cortical plasticity ; Somatosensory system ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The whisker-to-barrel pathway of the adult mouse was used in a study on the effects of peripheral sensory deprivation on GAD-immunoreactivity in the somatosensory cortex. At varying periods of time after removal of a set of vibrissal follicles, mice were processed for immunohistochemistry using an antibody against GAD. In sections tangential to the cortical surface we observed, in the barrels whose follicles were removed, decreased immunoreactivity as early as three days after surgery. The decrease was due to a lesser numerical density of stained puncta and to less intense staining of those remaining. GAD-positive somata were also less intensely stained, whereas their number did not seem to be changed. The changes, apparent at 3 days after the surgery, were restricted to the barrels corresponding to the removed follicles and were maximal at 2–4 weeks. At longer survival times (until 7 months) the immunoreactivity returned to normal, coincident with the regeneration of peripheral nerve fibres in the absence of their follicles. We conclude that GAD-immunoreactivity in the barrel cortex swiftly reacts to modifications of neuronal activity evoked in the periphery.
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