Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-1440
    Keywords: Isthmusstenosis ; Electronprobe microanalysis ; Calcification ; Arteriosclerosis ; Isthmusstenose ; Elektronenstrahlmikroanalyse ; Mineralisation ; Arteriosklerose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 5 Aorten mit Isthmusstenose (Coarctation) wurden mit Hilfe der Elektronenstrahlmikroanalyse untersucht (Alter: 2 Monate bis 34 Jahre). Es wurden Cryostatschnitte aus dem proximalen Bereich (hoher Blutdruck) und aus dem distalen Bereich (niedriger Blutdruck) hergestellt. Sie wurden in der Elektronenstrahlmikrosonde auf ihren Gehalt an Na, Mg, P, S, Cl, K und Ca quantitativ untersucht. Hier wird vorwiegend berichtet über die Messungen von Ca und P vom Lumen bis zur äußeren Media, da die Ca- und Phosphat-Ionen die Hauptbestandteile der Mineralablagerungen sind. Bei den jüngeren Stenosen bis 18 Jahre waren die Ca- und P-Gehalte nur in einem subintimalen Band erhöht. Bei der Stenose eines 34jährigen Patienten waren die Ca- und P-Gehalte proximal in der gesamten Media erhöht mit einem ausgeprägten Maximum in dem subintimalen Band. Distal waren die Ca- und P-Anreicherungen stets geringer als proximal. Nur im distalen Bereich beim 2 Monate alten Säugling konnten keine Anreicherungen gefunden werden, während sie proximal nachweisbar waren. Ein erhöhter Blutdruck führt also schon sehr früh zu einer bandartigen Anreicherung von Ca und P in der Aortenwand. Das zeigt, daß man mit der Elektronenstrahlmikrosonde, z.B. über die quantitative Registrierung von Ca und P, schon früh pathologische Veränderungen nachweisen kann.
    Notes: Summary Aortas with isthmusstenosis (coarctation) can be regarded as a model for those changes of the vessel wall, that depend on blood pressure, as one can compare the proximal region (high pressure) with the distal one (low pressure). The Na, Mg, P, S, Cl, K, and Ca content of the vessel walls of 5 patients (age: 2 months to 34 years) were determined by electronprobe microanalysis. We have used cryostat sections and measured the element concentrations from the lumen to the outer media. In this paper we discuss especially the measurements of Ca and P, as the mineral being deposited in the vessel wall, e.g. in arteriosclerosis, contains Ca and P. Up to 18 years Ca and P enrichments are found only in a subintimal band parallel to the lumen. The proximal region of the aorta of a 34 years old patient, however, demonstrated Ca and P enrichments in the whole media with a high peak in the subintimal band. The enrichments are proximally always higher than distally. Only in the distal region of the 2 months old infant no Ca or P enrichments were found, but they appeared proximally. Thus high blood pressure causes an enrichment of Ca and P in a subintimal band very rapidly and promotes the mineralization of the vessel wall. The quantitative electronprobe microanalysis demonstrated these pathological alterations.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Meteorology and atmospheric physics 66 (1998), S. 65-85 
    ISSN: 1436-5065
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Summary In this paper a retrieval technique for estimating rainfall rates is introduced. The novel feature of this technique is the combination of two satellite radiometers — the Special Sensor Microwave/Imager (SSM/I) and the Advanced Very High-Resolution Radiometer (AVHRR) — with mesoscale weather prediction model data. This offers an adjustment of the model atmospheres to reality which is necessary for calculating brightness temperatures that can be compared with microwave satellite measurements. In sensitivity studies it was found that the estimation of precipitation is determined to a high degree by the particle size distribution of rain and snow, especially by the size distribution of solid hydrometeors. These studies also reveal the influence of the knowledge of the correct cloud coverage inside a SSM/I pixel and the importance of using a realistic temperature profile instead of using standard atmospheres. The retrieval technique is based on radiative transfer calculations using the model of Kummerow et al. (1989). The algorithm consists of two parts: First Guess (FG) brightness temperatures for the SSM/I frequencies are generated as a function of the cloud top height and the cloud coverage, derived from AVHRR data and predictions from a meso-scale model. The rainfall rate of different types of clouds containing raindrops, ice particles and coexisting ice and water hydrometeors is then calculated as a function of the cloud top height. As an example, a strong convective rain event over the western part of Europe and over the Alps is taken to evaluate the performance of this technique. Good agreement with radar data from the German Weather Service was achieved. Compared to statistical rainfall algorithms, the current algorithm shows a better performance of detecting rainfall areas.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...