{HEAD ~ Additionally suitable gases} may include reactive gases or {TAIL ~ gases} with reactive components, or combinations thereof 
include
{ HEAD ~ Additionally suitable gases } may include reactive gases or { TAIL ~ gases } with reactive components , or combinations thereof
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH