Johan de Boer

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PURPOSE Fiducial markers are a good surrogate for the prostate but provide little information on the position and orientation of the seminal vesicles (SVs). Therefore, a more advanced localization method is warranted if the SVs are part of the target volume. The purpose of this study was to develop a hybrid registration technique for the localization of the(More)
Chemocommunication functions are known in many social mammals, such as gerbils, hamsters, and deer. But also mammals known as at least partly solitary do communicate by chemical signals. The existence and use of pheromones in domestic cats was the subject of this study. It turned out that male and female cats spent much time in exploring their own and(More)
PURPOSE Rotations of the prostate gland induce considerable geometric uncertainties in prostate cancer radiation therapy. Collimator and gantry angle adjustments can correct these rotations in intensity modulated radiation therapy. Modern volumetric modulated arc therapy (VMAT) treatments, however, include a wide range of beam orientations that differ in(More)
In a simulated open-field situation we tried to obtain information about the ability of tomcats to distinguish between urine marks of differing ages. Reactions to these marks were sniffing, sniffing intensively and "Flehmen". The variables we chose to demonstrate a possible discriminatory ability between urine marks of different ages were: (1) latency, i.e.(More)
The role of Fenton oxidants in DNA damage, aging, and cancer is appreciated, but not well understood. Six potential iron-binding (PIB) DNA motifs were previously identified as sites of preferential strand cleavage. Since DNA-metal binding domains are a known determinant of oxidative DNA damage, and the location of strand breaks explains where oxidant attack(More)
The dominance relationships in a group of adult male cats were studied by means of paired encounters in an observation arena which was equally familiar to both animals. In order to develop a good operational technique a pilot study was undertaken. Dominance relationships were determined by using criteria based upon approach/withdrawal or threatening(More)
A system for machine assisted karyotyping and chromosome analysis has been developed. The system uses a drum- or TV-scanner as input device, runs provisionally in 32 K memory, and also allows human interaction on several stages. The accuracy with which banded chromosomes are karyotyped depends strongly on the type of classifier and varies from 40 up to 80%.(More)
BACKGROUND Auditory verbal hallucinations (AVH) in psychotic patients are associated with activation of right hemisphere language areas, although this hemisphere is non-dominant in most people. Language generated in the right hemisphere can be observed in aphasia patients with left hemisphere damage. It is called "automatic speech", characterized by low(More)