Specificity means {HEAD ~ the ability} of {TAIL ~ the membrane} to selectively bind or filter certain species from complex mixtures 
of
Specificity means { HEAD ~ the ability } of { TAIL ~ the membrane } to selectively bind or filter certain species from complex mixtures
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH