Towards site-specific approaches

The combined features of structural adaptation in a specific hybrid nanospace and of a dynamic supramolecular selection process make the dynamic-site membranes, presented in the third part, of general interest for the development of a specific approach toward nanomembranes of increasing structural selectivity. From the conceptual point of view these membranes express a synergistic adaptative behavior the addition of the most suitable alkali ion drives a constitutional evolution of the membrane toward the selection and amplification of a specific transport crown-ether superstructure in the presence of the solute that promoted its generation in the first place. It embodies a constitutional selfreorganization (self-adaptation) of the membrane configuration producing an adaptative response in the presence of its solute. This is the first example of dynamic smart membranes where a solute induces the preparation of its own selective membrane. 

An interesting facet of this reaction involves the use of isotopically labelled acid derivatives, leading to pyrylium salts with 14C labels at specific sites. In view of the reactivity of pyrylium salts towards nucleophiles, this approach provides access to a range of labelled aromatic and heteroaromatic compounds (62MI22401). 

Thermodynamic stability is a global property of the enzyme structure, and contributions of individual amino acids toward the free energy of folding are additive and highly cooperative. Analysis of mutant proteins has defined the contributions of various amino acids toward the overall stability of the protein. Replacements which alter the formation of ion pairs, hydrogen bonds, van der Waals contacts, or hydrophobic interactions each tend to destabilize the folded protein by a qualitatively comparable amount (14). In one approach to this problem, site-specific substitution of amino acids has provided new approaches toward dissecting the kinetic mechanisms of protein folding (27). 

The conclusions reached from these data argue that instead of continuing the search based only on the discovery of new organisms with antimicrobial activities, future searches need to be directed toward discovery of drugs specifically active against new target sites. This approach, described in more detail in Section IV, is being taken seriously today. 

Evolution in telescope making since the Palomar has not been limited to the area of optical production. The alt-azimuthal mount has become the established solution since the Bolshoi 6 m telescope, for its superior mechanical performance and the compact, cost-efficient enclosure design it allows. Better understanding of the properties of atmospheric turbulence allowed a more accurate characterization of a telescope properties, a more balanced approach towards specifications and error budgeting and a better understanding of the utmost importance of site selection. Any ground-based telescope of appreciable size will be primarily limited by the effect of atmospheric turbulence, not to mention the proportion of photometric nights allowed by weather conditions. 

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