In {TAIL ~ an embodiment}, {HEAD ~ the barrier region} 38 is significantly less conductive than the regions 34 
In
In { TAIL ~ an embodiment } , { HEAD ~ the barrier region } 38 is significantly less conductive than the regions 34
REL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH