Molecular beam study of CO chemisorption on alumina-supported Pd particles

The adsorption of carbon monoxide on small alumina-supported Pd particles and on a Pd(111) single crystal has been studied with a molecular beam techniques. The measured sticking coefficient shows that CO adsorbs on palladium surface according to precursor states. It is noted that a temperature dependent diffusion of gas molecules on the support influences the sticking probability of CO.     

How the design of an experiment influences the nonsensitiveness regions in models with variance components

Nonsensitiveness regions for estimators of linear functions, for confidence ellipsoids, for the level of a test of a linear hypothesis on parameters and for the value of the power function are investigated in a linear model with variance components.The influence of the design of an experiment on the nonsensitiveness regions mentioned is numerically demonstrated and discussed on an example.     

A new method for characterization of low grade gliomas using ultra low field magnetic resonance imaging

Low grade gliomas were studied with ultra low field magnetic resonance imaging (ULF MRI). The tumors exhibited high tissue contrast in both T₁ and T₂-weighted images as compared to normal brain tissue. Moreover they were sharply delineated towards the surrounding brain tissue. When compared with X-ray computed tomography the tumors were more readily detected and delineated by using ultra-low field magnetic imaging. A computerassisted classification procedure was used to define new regions of interest for relaxation time estimation. By using this procedure more accurate estimations of the T₁ and T₂ values were obtained.     

Nonlinear Impulse Target Problems under State Constraint: A Numerical Analysis Based on Viability Theory

We study the problem of reaching a target without leaving a prescribed set for controlled impulse dynamics. First, we provide a numerical procedure for the approximation of the set of initial conditions from which the objective can be met. Then we show that the minimum time function associated with this target problem can be approached by a sequence of value functions for suitable discrete-time systems. This can be deduced from the fact that the epigraph of the minimum time function is the set of initial conditions from which a target can be reached without leaving a constraint set for an auxiliary impulse system. In this case, the numerical procedure for the qualitative target problem can be simplified. We provide results for estimating the convergence rate of the simplified scheme.     

Six new photolabile linkers for solid-phase synthesis. 1. Methods of preparation

In the synthesis of combinatorial chemical libraries on solid phase, there is a need to cleave the compounds from the solid support before the library can be tested for biological activity. It is advantageous to use linkers which will release the libraries by mild photolytic cleavage. We have developed six new linkers of the photosensitive α-methyl 2-nitrobenzyl type containing amino, hydroxy, bromo and methylamino groups, and also 4-nitrophenoxycarbonyl activated OH and NH₂ groups. This revised version was published online in August 2006 with corrections to the Cover Date.     

Improvements and some results of the N/F-activation method for dating fossil bone

A non-destructive 14 MeV-neutron activation technique for the measurement of nitrogen and fluorine contents in fossil bones, described in a previous paper, has been improved and applied in an attempt to date fossil skeleton material from Austrian caves.