{TAIL ~ The column} may be closed at {HEAD ~ the ends} and shaken and washed with an enzymatic buffer 
{ TAIL ~ The column } may be closed at { HEAD ~ the ends } and shaken and washed with an enzymatic buffer
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH