In {TAIL ~ certain preferred embodiments}, {HEAD ~ the molar ration} of : is in the range of 1:2 to 1:20 
In { TAIL ~ certain preferred embodiments } , { HEAD ~ the molar ration } of : is in the range of 1:2 to 1:20
REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH