Carbonic anhydrase inhibitors: X-ray crystallographic studies for the binding of N-substituted benzenesulfonamides to human isoform II

N-substituted benzenesulfonamides, incorporating the N-amino-, N-hydroxy- and N-methoxy-moieties at the sulfonamide zinc binding group, have been investigated as CAIs by means of inhibition and structural studies, unraveling interesting aspects related to their inhibition mechanism.     

Solvent effects on the complexation of 1-alkanols by parent and modified cyclodextrins. Calorimetric studies at 298 K

The formation of complexes of parent and alkylated cyclodextrins (CDs) with 1-heptanol and 1-octanol has been studied calorimetrically at 298 K in water and in concentrated aqueous solutions of urea. The forces involved in the association process are discussed in the light of the signs and values of the thermodynamic parameters obtained: association enthalpy, binding constant, Gibbs free energy, and entropy. It was inferred that: (i) in water, the formation of complexes for parent and substituted α-cyclodextrins (αCDs) is determined by enthalpy. For parent and substituted β-cyclodextrins (βCDs), instead, hydrophobic interactions are the prevailing forces determining complexation, as indicated by the small and negative or positive enthalpies and by the high and positive entropies. (ii) In urea, hydrophilic interactions are attenuated. The formation of complexes with alkylated CDs does not occur. (iii) The analysis of the thermodynamic properties confirms that inclusion is a process dominated by hydration phenomena. Modifications experienced by the solvent water in the hydration shells of the interacting substances upon association determine the formation of the complexes.     

A convenient synthesis of unsymmetrically substituted terphenyls of biologically active stilbenes via a double Suzuki cross-coupling protocol

A double Suzuki cross-coupling protocol has been devised as a practical route to a variety of terphenyls. Good chemoselectivity was observed. Unsymmetrically substituted triphenylenes were also easily prepared.     

La hessiana e i suoi problemi

This lecture shows synthetically the developments of the researches on the Hessian of an algebraic hypersurface ofd dimensions, with a particular view of the plane case (d = 2), and points out several solved and unsolved problems on this subject.     

Broadband measurements of acoustic attenuation in water-saturated sands

A method for the measurement of acoustic attenuation in water-saturated granular media as a continuous function of frequency is described. Results for a range of water-saturated sands are presented together with acoustic velocity data and discussed in relation with porosity and grain size variations.     

A simplified,miniature TEA-CO2 laser using a semiconductive pre-ionization technique

Using a pre-ionization system based on a silicon carbide compound and a pulse-forming network using a vacuum relay, we have been able to significantly reduce TEA0-CO₂ laser complexity while maintaining high output energy densities. The design and construction are detailed along with the experimentally obtained laser characteristics.     

Molecular recognition: A thermodynamic study of non bonded interactions in aqueous solutions of iminoacids. Effects of steric and geometric isomerism

Enthalpies of dilution of binary and ternary aqueous solutions containing L-and D-proline, cis-L- and cis-D-4-hydroxy proline, trans-L-4-hydroxy proline, have been determined by flow calorimetry at 25°C. Pairwise self-and cross-interaction coefficients of the virial expansion of the excess enthalpies were evaluated. They are positive for solutions of unsubstituted prolines. On the contrary, upon the introduction of a hydroxy group, they become negative, reaching the largest value for the cis-L-lcis-D-4-hydroxy proline system. The results are interpreted in terms of preferential configurations, stabilized by interactions between the hydrophilic groups.