Electronic Stopping of Slow Protons in Oxides: Scaling Properties

Electronic stopping of slow protons in ZnO, VO_{2} (metal and semiconductor phases), HfO_{2}, and Ta_{2}O_{5} was investigated experimentally. As a comparison of the resulting stopping cross sections (SCS) to data for Al_{2}O_{3} and SiO_{2} reveals, electronic stopping of slow protons does not correlate with electronic properties of the specific material such as band gap energies. Instead, the oxygen 2p states are decisive, as corroborated by density functional theory calculations of the electronic densities of states. Hence, at low ion velocities the SCS of an oxide primarily scales with its oxygen density.

Electronic Stopping of Slow Protons in Transition and Rare Earth Metals: Breakdown of the Free Electron Gas Concept

The electronic stopping cross sections (SCS) of Ta and Gd for slow protons have been investigated experimentally. The data are compared to the results for Pt and Au to learn how electronic stopping in transition and rare earth metals correlates with features of the electronic band structures. The extraordinarily high SCS observed for protons in Ta and Gd cannot be understood in terms of a free electron gas model, but are related to the high densities of both occupied and unoccupied electronic states in these metals.

Cecal perforation in alcoholic pancreatitis

A 51-YEar old male with alcoholic pancreatitis progressed to bowel inflammation and cecal perforation. Colonic complications of pancreatitis include fistula, stenosis, necrosis and perforation. The pathogenesis of these entities is discussed and the literature regarding colonic complications is reviewed. Although it is uncommon, bowel involvement in pancreatitis is potentially lethal and may necessitate surgery in an otherwise medically managed illness.