In the active versions, the leaflets are constructed such that they provide {HEAD ~ minimal resistance} to {TAIL ~ the flow} with minimal rise in the pressure across the valve, similar to the disclosed valves in the aforementioned patents 
to
In the active versions , the leaflets are constructed such that they provide { HEAD ~ minimal resistance } to { TAIL ~ the flow } with minimal rise in the pressure across the valve , similar to the disclosed valves in the aforementioned patents
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH