Comparison of Electron and Ion Emission from Xenon Cluster-Induced Ignition of Helium Nanodroplets.

The charging dynamics of helium droplets driven by embedded xenon cluster ignition in strong laser fields is studied by comparing the abundances of helium and highly charged Xe ions to the electron signal. Femtosecond pump-probe experiments show that near the optimal delay for highly charged xenon the electron yield increases, especially at low energies. The electron signature can be traced back to the ionization of the helium environment by Xe seed electrons.

Particulate matter from both heavy fuel oil and diesel fuel shipping emissions show strong biological effects on human lung cells at realistic and comparable in vitro exposure conditions.

Background: Ship engine emissions are important with regard to lung and cardiovascular diseases especially in coastal regions worldwide. Known cellular responses to combustion particles include oxidative stress and inflammatory signalling.

Objectives: To provide a molecular link between the chemical and physical characteristics of ship emission particles and the cellular responses they elicit and to identify potentially harmful fractions in shipping emission aerosols.