{HEAD ~ The soft emission} of electrons from {TAIL ~ the beta emitting gas} can not penetrate the glass wall of the microspheres, thereby constituting no radiation hazard 
{ HEAD ~ The soft emission } of electrons from { TAIL ~ the beta emitting gas } can not penetrate the glass wall of the microspheres , thereby constituting no radiation hazard
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH