The size D of {HEAD ~ the current path} is {TAIL ~ 0.5 to 10 nm}, and typically 1 to 6 nm 
The size D of { HEAD ~ the current path } is { TAIL ~ 0.5 to 10 nm } , and typically 1 to 6 nm
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH