"SIO_000887" . _:vb50934972 ":arcc045b415" . _:vb50934972 . "buffer role"@en . . "A buffer role is the role of a chemical substance which maintains a pH at a near constant value."@en . _:vb50934972 . . _:vb50934972 . _:vb50934972 . . . _:vb50934972 .