The invention is directed to veneer ceramics for dental restorations of framework ceramics comprising yttrium-stabilized zirconium dioxide. The second diffractive structure may serve as a vortex lens. When R1 is hydroxy, the hydroxy or ester substituent may have either an \u03b1 or a \u03b2 orientation. These compounds can be used for rapidly detecting food pathogens and for determining sterilization effectiveness. The slave circuit provides a third reference voltage based on the filtered second reference voltage and the filtered supply voltage.