Publications by authors named "Raphael Hahn"

We have performed a study of several cesium oven designs. A comparison between recirculating (or sticking-wall) and collimating (or re-emitting-wall) ovens is made in order to extract the most efficient design in terms of beam brightness. Unfortunately, non-reproducible behaviors have been observed, and the most often observed output flux is similar to the sticking-wall case, which is the lowest theoretical value of the two cases, with a beam brightness close to 10 at.

View Article and Find Full Text PDF

An electron optical column has been designed for High Resolution Electron Energy Loss Microscopy (HREELM). The column is composed of electron lenses and a beam separator that are placed between an electron source based on a laser excited cesium atom beam and a time-of-flight (ToF) spectrometer or a hemispherical analyzer (HSA). The instrument will be able to perform full field low energy electron imaging of surfaces with sub-micron spatial resolution and meV energy resolution necessary for the analysis of local vibrational spectra.

View Article and Find Full Text PDF

Vascular aging is characterized by the presence of chronic oxidative stress. Although cytosolic Sod 1 has a key role in the detoxification of superoxide ((*)O(2)(-)), little is known about its importance in vascular aging. We found that inhibition of Sod 1 had no effect on (*)O2- generation.

View Article and Find Full Text PDF

We investigated the effects of aging and ischemia-reperfusion (I/R) injury on the expression and activity of nitric oxide (*NO) synthases and superoxide dismutase (SOD) isoforms. To this end we perfused excised hearts from young (6 months old) and old (31-34 months old) rats according to the Langendorff technique. The isolated hearts were, after baseline perfusion for 30 min, either subjected to 20 min of global no-flow ischemia followed by 40 min of reperfusion or were control-perfused (60 min normoxic perfusion).

View Article and Find Full Text PDF