{HEAD ~ These ring compounds} are maintained in a concentration of between 0.01 and 4.0 grams per liter of solution in {TAIL ~ the bath} 
{ HEAD ~ These ring compounds } are maintained in a concentration of between 0.01 and 4.0 grams per liter of solution in { TAIL ~ the bath }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL