Use "and" instead of &, unless part of a proper noun or a common abbreviation. For example: Notices and slips, not Notices & slips; Baker & Taylor, R&D.
OPAC
Base terminology
Use "OPAC", not "Opac" or "opac" when abbreviating online public access catalog(ue), including in system preference names.
staff interface
Base terminology
Use "staff interface", not "staff client", "staff intranet", or "intranet".