(Rc), ???C(O)N(Rc)(Rc), or Ra or Rb may independently be joined to one or both of R7 or E (where E is other than O, S or ???CH???CH???) to form an alkylene bridge between the terminal nitrogen and the alkyl portion of the Ra or Rb and the R7 or E group, wherein the bridge contains 1 to 8 carbon atoms; or Ra and Rb may be joined to one another to form a (C3-C7)cycloalkyl; Rc, for each occurrence, i