Direct acid casting technique

In slower production processes, atomic absorption can be used directly for production control of those processes for which rapid sample preparation techniques have been developed. One such example is the determination of magnesium concentration during the production of cast iron [70]. A further example is the determination of acid soluble aluminium in steel [147], where in large steel companies 100 samples or more per day may be required. (See also section II.A.)... 

A second example of the use of directed molecular evolution for natural product synthesis is the use of lipases by Reetz and colleagues. This work is based on the kinetic hydrolytic resolution of racemic mixtures, in which one enantiomer is preferentially hydrolyzed and the chiral product is thus enriched. Utilizing both random mutagenesis and directed techniques such as CAST,64 they have improved the stereoselectivity of a lipase from Pseudomonas aeruginosa (PAL) on a number of occasions with different substrates. One of the first examples utilized the model substrate 2-methyldecanoic acid /xnitrophenyl ester, for which the wild-type enzyme has an enantioselectivity of E= 1.1. As a consequence of five mutations accumulated through random mutagenesis, followed by saturation mutagenesis, the enantioselectivity was increased to 25.8.123 More... 

Techniques for membrane casting from organic solutions and casting directly from acid solutions have been developed. 

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