The present invention provides transcription factors associated with the hedgehog signaling pathway that are regulated by dephosphorylation by phosphatases. A precise amount of this coated shot may then be mixed with a measured quantity of silicon pellets and the resulting mixture may then be melted to provide a boron-doped silicon melt for use in growing p-type silicon bodies that can be converted to substrates for photovoltaic solar cells. A membrane is received in the groove and extends across the cavity.