Besides surface chemistry, the surface roughness on the micrometer scale is known to dominate the wetting behavior and the biocompatiblity properties of solid-state materials. The significance of topographic features with nanometer size, however, has yet to be demonstrated. Our approach is based on well-defined Ge nanopyramids naturally grown on Si(001) using ultrahigh vacuum chemical vapor deposition, where the nanopyramid density can be precisely controlled by the growth conditions. Since the geometry of the nanopyramids, often termed dome clusters, is known, the surface roughness can be characterized by the Wenzel ratio with previously unattainable precision. Dynamic contact-angle measurements and adsorption of γ-globulin as a function of that ratio demonstrate the strong correlation between surface nanoarchitecture, on one hand, and wetting behavior and biocompatibility, on the other hand. Related x-ray photoelectron spectroscopy measurements reveal that potential changes of surface composition can be definitely excluded.

XMM-Newton is the second cornerstone mission of the ESA Horizon 2000 programme.Due to the excellent performance of the operations and spacecraft, and to cope with the expected long duration of the mission, it was decided to migrate the mission control system from the old SCOS-I system to the new SCOS-2000 mission control infrastructure. The paper describes how the overall objectives of the migration process have been achieved, including the preservation of the science quality, operational efficiency, system performance and external interfaces. The paper discusses the validation strategy and test approach that were driven by the needs of minimizing the impact on science operations, avoiding any disruption in the science pipeline and in the science data distribution cycle. Given the distributed nature of the control system, good coordination and maximum synergies were essential aspects of the project. The migrated system has been in operations since June 2005. This paper is presented on behalf of the SCOS-2000 Migration Team that played a fundamental role in the success of the project.