The invention provides nitrilases and methods for making and using them, and in one aspect, provides methods for producing enantiomerically pure \u03b1-substituted carboxylic acids, such as, for example, \u03b1-amino acids and \u03b1-hydroxy acids. The systems and methods use of differential polarimetry to measure optical constants and thickness of ultra-thin films. The parison has an external diameter of from 17. This may improve the utilization of a bus over which the memory module communicates with the controller.