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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Electrical engineering 63 (1981), S. 117-124 
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents Unbalanced magnetic pull (u.m.p.) in induction and synchronous machines is usually calculated by integrating the mechanical tension on the eccentric rotor around its surface. The invariant u.m.p. follows from parametric magnetic fields in the air-gap caused by a 2-pole-oscillation of the magnetic resistance. Whe deriving the u.m.p. from the magnetic energy it bcomes evident that the energy of the parametric waves is always zero. The apparent discrepancy between the
    Notes: Übersicht Bei dem herkömmlichen Berechnungsverfahren für die einseitig magnetischen zugkräfte in Drehfeldmaschinen geht man von den Maxwell'schen Zugspannungen aus, die auf einen exzentrischen Läufer wirken. Der zeitlich konstante einseitig magnetische Zug ergibt sich aus parametrisch erregten Luftspaltfeldern, welche durch Leitwertschwankungen der Polpaarzahl eins entstehen. Die alteinative Ermittlung der Zugkräfte aus der magnetischen Energie des Luftspaltfeldes zeigt, daß Leitwertrehwellen der Polpaarzahl eins keinen Beitrag liefern. In dem Aufsatz wird der scheinbare Widerspruch zwischen den beiden Berechnungsverfahren aufgeklärt. Sowohl die Behandlung in mathematisch geschlossener Form als auch die Anwendung der Drehfeldtheorie ergeben, daß neben den bisher bekannten Gleichkräften bei Läuferexzentrizitäten zusätzliche Wechselkräfte entstehen, deren Frequenz bei statischen Exzentrizitäten gleich der doppelten Netzfrequenz und bei dynamischen Exzentrizitäten gleich der doppelten Schlupffrequenz ist. Die Amplituden der Wechselkräfte hängen von Polzahl und Größe der Verlagerung ab; bei zweipoligen Maschinen liegen sie in der Größenordnung von 50% der Gleichkräfte. Die Kräfte werden für Sperisung der Maschine aus einem starren Netz und mit konstanten Strom berechnet. Bei kleinen Exzentrizitäten sind die Unterschiede gering. Die bisher nicht beachteten einseitig magnetischen Wechselkräfte wurden an zwei Maschinen auch experimentell nachgewiesen. Um die fundamentalen Wirkungsmechanismen offen zu legen, wurden in der Arbeit Eisensättigung und Läuferrückwirkung vernachlässigt und nur der Grund-Strombelag berücksichtigt.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 62 (1983), S. 15-23 
    ISSN: 1432-0533
    Keywords: Brain death ; Ischemic neuronal alterations ; Brain stem ; Meningoencephalitic reaction ; Reperfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The varying cell picture of the brain in brain death is impressive. Some authors have interpreted this cell picture as a result of intravital autolysis and others as necrosis, at which the maturation time obviously plays an important part. The following time-dependent cerebral changes were established on the basis of an evaluation of 190 brain death cases: (1) neuronal necroses that arise at different rates within the cerebral cortex and the lower brain stem; (2) a hemorrhagic-meningoencephalitic reaction that occurs exclusively at least 4 days after brain death or hemorrhages alone after intervals of at least 48 h; and (3) a washed-out tissue picture. The alterations in the spinal border zone of the total infarction, like in the brain itself, increase rapidly after 48 h. The regular onset of inflammatory alterations after long brain death intervals can only be explained by partial recirculation due to a decline of the high intracranial pressure. The hermorrhages and increasing necroses in some cases with longer intervals therefore are likewise evidence of a not entirely complete cerebral ischemia in spite of an angiographically demonstrable circulatory arrest.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 52 (1980), S. 147-151 
    ISSN: 1432-0533
    Keywords: Special chromolipids ; Histochemistry ; Fluorescent microscopy ; Hemorrhagic brain tissue necroses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A serial and comparative histochemical examination of lipopigments in human brain tissue necroses led to a more exact characterization of a chromolipid called “hemoceroid”. It arises only in necroses with hemorrhages and not in anemic necroses nor in subdural hematomas. Its histochemical properties differ from those of all developmental stages of ceroid. An ageing phenomenon is absent. The very intense autofluorescence of the thick, clotted pigment ist striking. Hemoceroid seems to arise extracellularly and is absorbed secondarily by macrophages.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 52 (1980), S. 141-145 
    ISSN: 1432-0533
    Keywords: Brain tissue necrosis ; Phagocytic pigments ; Ceroid ; Pigment maturation ; Histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ceroid pigment of macrophages were subdivided into four different types according to their own color and their ability to stain with luxol fast blue. With reference to this mode a series of more than 200 brain infarcts which had happened 1 day to 56 years before death, was examined systematically. According to the results the ceroid variants do not only succeed one another chronologically but they also represent histochemically successive phases of development which correspond to the progressive auto-oxidation of unsaturated lipids. The occurrence of the different stages is chronologically defined. During this development cortical and subcortical macrophages show different speeds in the ageing process of their pigments. There is no evidence for an essential participation of proteins in the maturation of the ceroid. Not during any phase of development is the reaction pattern identical with that of neuronal and glial lipofuscin.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 58 (1980), S. 53-54 
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Acta neurochirurgica 64 (1982), S. 215-224 
    ISSN: 0942-0940
    Keywords: Medulloblastoma ; histological variants ; biological behaviour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a series of 310 cases the role of the factors age, sex, location of the tumour (midline or lateral), and medulloblastoma type (classic or desmoplastic) were analysed with regard to the prognosis. The influence of therapy is not considered because of the inhomogeneity of the material and the view nowadays that treatment is insufficient. The occurrence of lateral (or hemispheric) medulloblastomas increases in the group of the 11–15 years old patients. The proportion of the desmoplastic type is greater in adults than in children, but they are distributed almost equally medially and laterally. There seems to be no definite correlation between sex and the survival time. The mean survival time increases with age. With regard to the histological subclassification into children and adults, the mean survival times are nearly identical. The only obvious factor with a decisive influence on the prognosis seems to be the time of appearance of the tumour. Additionally, the data support the conclusion that a desmoplastic medulloblastoma should be considered as a histological variant without clinical relevance.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In autopsied brain tissue from three cases with Leigh disease (subacute necrotizing encephalomyelitis, SNE) and controls, the activity of pyruvate dehydrogenase complex (PDHC) was determined under different conditions. It was found to be at the control level or increased, but not deficient. The activities of succinate dehydrogenase, fumarase, succinate cytochrome c reductase, cytochrome c oxidase, and glutamate dehydrogenase were measured as additional mitochondrial markers and showed no essential differences between SNE and control tissue. The metabolic defect in SNE remains unknown. According to the literature, the defect may be localized to the mitochondrial systems. However, the reported results indicate that it cannot be ascribed to PDHC function. Extensive biochemical studies are necessary for understanding of the pathogenesis in the fatal genetic metabolic disease.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    International journal of legal medicine 89 (1983), S. 247-265 
    ISSN: 1437-1596
    Keywords: Suicide, hanging ; Congestion bleedings, hanging ; Suicid, Erhängen ; Stauungsblutungen, Erhängen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Description / Table of Contents: Zusammenfassung In einer prospektiven Untersuchung fanden sich bei 204 unausgewählten Fällen suicidalen Erhängens in 51% Stauungsblutungen verschiedener Schweregrade. Sie bestanden beim typischen symmetrischen Erhängen (n=38) in 42%, beim atypischen (n=152) in 53%. Der Unterschied war nicht signifikant. Zwischen den äußeren Stauungsblutungen einschließlich denen in den Halsweichteilen einerseits und der Hangform, der Schlingenführung sowie der Breite des Strangwerkzeuges konnten statistisch keine Zusammenhänge gesichert werden. Eine nur geringe Abhängigkeit ergab sich lediglich vom Alkoholgehalt des Blutes. Das Hirngewicht der Erhängten lag in allen Altersklassen über dem eines klinischen Vergleichskollektivs. Es zeigte ebenfalls keinen Zusammenhang mit der Ausprägung der äußeren Stauungszeichen. Bei 36 histologisch untersuchten Gehirnen lag in 78% eine Hyperämie vor. Sie betraf vorwiegend das Stromgebiet der Venolen, aber auch der Kapillaren, und war sowohl beim typischen als auch beim atypischen Erhängen festzustellen. Unabhängig von äußeren Stauungsblutungen und der cerebralen Hyperämie war es in 50% der Fälle zu Blutungen in die Gefäßscheiden cerebraler Gefäße gekommen. Die Hirngewichtszunahme wird entsprechend den histologischen Zeichen des Ödems beim Erhängen auf eine terminal-postmortale Hirnschwellung zurückgeführt, wie sie bei allen Formen perakuten Todes bekannt ist. Sie steht nicht mit der Strangulationsart und dem Vorliegen oder Fehlen von Stauungszeichen in Zusammenhang. Auch bei atypischen Formen des Erhängens ergibt sich kein Hinweis auf eine cerebrale Restdurchblutung.
    Notes: Summary In a prospective study of 204 unselected cases of suicidal hanging congestion bleedings of different degrees were found in 51%. In typical symmetrical hanging (n=38) they occurred in 42% of cases, in atypical suspension (n=152) in 53%. The difference had no statistical significance. Statistically, no connection could be secured between the outer congestion bleedings including those within the neck soft tissue on the one hand, and the form of hanging, the kind of loop or the breadth of the strangulation tool on the other. Only a slight dependence on the blood alcohol content was established. The brain weight of the hanged cases was higher in all age groups than in a clinical autopsy collective. Likewise, it showed statistically no relation to the degree of the outer congestion signs. In 36 cases the brain was histologically investigated. In 78% of cases hyperemia was found, concerning predominantly the supply tract of venoles, but also the capillary part. It existed both in typical and in atypical hanging. Independent of outer congestion signs and of cerebral hyperemia, small bleedings into the cerebral perivascular space could be observed in 50% of cases. The increase in brain weight in association with histological signs of edema in hanging was put down to a definite terminal-postmortal brain swelling, as it is known in all forms of peracute death. There is no connection with the type of suspension and the existence or non-existence of congestion signs. Also in atypical forms of hanging no reference to a cerebral residual perfusion is given.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1437-2320
    Keywords: Brain death ; Malignant brain swelling ; Temporal pattern ; Hirntod ; Maligne verlaufende Hirnschwellung ; Zeitverläufe
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Dynamik der therapeutisch nicht beeinflußbaren Hirnschwellung wurde an 96 autopsierten Fällen analysiert. Sie waren aus einem großen Material von Hirntod-Fällen nach folgenden Gesichtspunkten ausgewählt worden: die Initialläsion wie auch der Eintritt des Hirntodes waren zeitlich genügend scharf bestimmbar, sie hatten weder Entzündungen noch Tumoren oder Hirnoperationen, sie waren nicht Kinder unter 1 Jahr und sie hatten keine sekundären Infarkte oder Rezidivblutungen nach einer Aneurysma-Ruptur. Die Daten zeigen eine ausgeprägte Variation des Zeitintervalles von der Primärläsion bis zum Eintritt des Hirntodes. Sie reicht von 0 Stunden bis zu 11 Tagen mit einem Medianwert von 24 Stunden. Diese Intervalle sind unabhängig von Art und Schwere der Initialläsion (Tab. I) und vom Alter (Tab. II) mit Ausnahme von Kindern unter 10 Jahren, die nach Kürzerer Zeitdauer gestorben waren. Der Schwellungsprozeß zeigt also eine Eigendynamik, die aber wegen der großen Variation nicht durch stetige Progression erklärt werden kann. Die Analyse der Zeitspannen mit Hilfe des Weibull-Wahrscheinlichkeitsnetzes (Abb. 2) zeigt eine bimodale Häufigkeitsverteilung, die aus der Überlagerung von 2 Faktoren zu erklären ist, nämlich: 1. dem Hirnödem und 2. dem finalen Verlust der Autoregulation der Hirngefäße mit irreversibler Schwellung des Gehirns und hochgradiger intrakranieller Druckerhöhung. Im Durchschnitt verläuft die maligne, letal endende Hirnschwellung rascher als das übliche Hirnödem. Sie wird aber bis zu 11 Tagen beobachtet, ohne daß Hinweise auf sekundär entstandene Hirnschäden vorliegen.
    Notes: Summary The dynamics of brain swelling which does not respond to any form of treatment was analysed in 96 autopsy cases. These were selected from many cases of brain death, according to the following criteria: the time of occurrence of the initial lesion, as well as the onset of brain death, could be precisely determined; the patients had no inflammation, tumour of the brain or previous brain operation; there were no children under one year of age and there were no secondary infarctions or recurrences of bleeding after rupture of an aneurysm. The findings show a wide variation in the period of time between the primary lesion and the onset of brain death. This ranges from zero hours to eleven days, with a median of 24 hours. These intervals are independent of the nature and severity of the lesion (Table I) and of the age (Table II) with the exception of children under ten years, who died after a shorter interval. This process of brain swelling appears to show inherent dynamics, which because of the great variation cannot be explained by a steady progression. The analysis of the time intervals on Weibull-probability graph-paper (Figure 2) shows a bimodal frequency distribution, which can be explained by the superimposition of two factors, namely (i) brain oedema and (ii) a final loss of autoregulation of the cerebral vessels with irreversible swelling of the brain and severe intracranial hypertension. On average, this malignant and fatal brain swelling advances more rapidly than the “ordinary” brain oedema, but it can be observed up to eleven days without any signs of secondary damage to the brain.
    Type of Medium: Electronic Resource
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