PubMed Health⌕ Search

Biomedical subjects

H Kolanoski

Publications and source records attributed to H Kolanoski.

4 recordsLinked to original sources
PubMed2004

Limits for the central production of Theta+ and Xi(--)pentaquarks in 920-GeV pA collisions.

We have searched for Theta+(1540) and Xi(--)(1862) pentaquark candidates in proton-induced reactions on C, Ti, and W targets at midrapidity and square root of s = 41.6 GeV. In 2 x 10(8) inelastic events we find no evidence for narrow (sigma approximately 5 MeV) signals in the Theta+ --> pK0(S) and Xi(--) --> Xi- pi- channels; our 95% C.L. upper limits (UL) for the inclusive production cross section times branching fraction B dsigma/dy/(y approximately 0) are (4-16) mub/N for a Theta+ mass between 1521 and 1555 MeV, and 2.5 mub/N for the Xi(--). The UL of the yield ratio of Theta+/Lambda(1520) < (3-12)% is significantly lower than model predictions. Our UL of B Xi(--)/Xi(1530)0 < 4% is at variance with the results that have provided the first evidence for the Xi(--).

Journal Article↗
PubMed1999

Fluorescence 125I eye applicator.

A new approach to optimize curative eye plaque brachytherapy is presented. The application of ophthalmic plaques is a common therapy modality for small and medium sized intraocular tumors. At Essen University Hospital eye applicators with photon emitting 125I seeds are used for the treatment of tumors with a thickness from 5 to 10 mm. Our clinical experiences indicate that the dose distributions of these applicators-used so far worldwide-are not optimal. A steeper dose falloff would meet the radiobiological requirements better, to provide the eradication of all tumor cells as well as sufficient occlusion of tumor supplying blood vessels. Our investigations for eye plaque optimization are based both on measurements and Monte Carlo simulation. For fast dosimetric measurements we have built a computer controlled device which allows reading out, directly and simultaneously, 16 1 mm3 scintillators. For the numerical simulations of the dose distribution of 125I eye plaques we have adapted a Monte Carlo program originally developed to calculate the synchrotron radiation in particle physics. We have investigated the influence of geometrical as well as physical eye plaque parameters on the dose distribution: Shielding of the primary radiation, penumbra modification, and energy conversion by exploiting fluorescence x-radiation have been considered. New types of fluorescence eye applicators have been designed which are more suitable for the prevention of radiopathic effects on structures at risk.

Brachytherapy↗