Patroon en beeld tussen informatie en kennis

Rede, uitgesproken bij de aanvaarding van de functie van hoogleraar in de Faculteit der Geneeskunde en Gezondheidswetenschappen van de Erasmus Universiteit te Rotterdam, met de leeropdracht medische informatica in het bijzonder de methodologie van de signaal- en patrooninterpretatie, op donderdag 28 april 198

A new representation of acid-base disturbances

The acid-base status of intensive care patients is monitored on the basis of three quantities. The graphical representation which may be of help for the monitoring task is therefore cumbersome. The classical Siggaard-Andersen acid-base chart is such a representation, but it is only suited for evaluating one acid-base status at a time and not for representing acid-base paths. A new representation, obtained after a principal components transformation is presented. It is shown that the representation is characteristic for the laboratory instrument used. Its most attractive feature is that it is distortionless with respect to the three-dimensional configuration

New developments and applications in quantitative electron spectroscopic imaging of iron in human liver biopsies

Reliable iron concentration data can be obtained by quantitative analyses of image sequences, acquired by electron spectroscopic imaging. A number of requirements are formulated for the successful application of this recently developed in situ quantitative type of analysis. A demonstration of the procedures is given. By application of the technique it is established that there are no significant differences in the average iron loading of structures analysed in liver parenchymal cells of a patient with an iron storage disease, before and after phlebotomy. This supports the hypothesis that the process of iron unloading is an organelle specific process. Measurement of the binary morphology, represented by the area and contour ratio of the iron containing objects revealed no information about differences between the objects. This finding contradicts the visual suggestion that ferritin clusters are more irregularly shaped than the other iron objects. Also, no differences could be found in this sense between the situations before and after phlebotomy. With respect to the density appearance, objects that have an inhomogeneous iron loading averagely contain more iron. This observation does correspond well with the visual impression of the increasingly irregular appearance of more well-loaded structures

Precision measurements of the half-lives of the positon emitters 25Al, 26Alm, and 33Cl

The half-lives of the positon emitters 25A1, 26Alm, and 33Cl, produced by (p,y) reactions at selected resonances, have been measured by means of two different methods: a) with a 70-channel pulse-analyser using time-to-pulse-height conversion; b) with an eleven-contact stepping switch and eleven sets of scales and mechanical registers. The results are: 25Al 7.24 ± 0.03 sec; 26Alm 6.28 ±0.04 sec; 33Cl 2.53 ± 0.02 sec