Advanced computing solutions for health care and medicine

This guest editorial introduces the special issue on “Advanced Computing Solutions for Health Care and Medicine”. The goal of this special issue was to collect high quality papers describing the application of computer science methods and techniques to main health care and clinical problems, resulting in high performance applications or prototypes for medical and clinical environments. The special issue touched different health informatics hot topics and is organized in four sections: (i) clinical decision support systems; (ii) biomedical imaging; (iii) high performance computing and biomedical simulations; (iv) bioinformatics data analysis.     

Combination of click chemistry and sulfonamides to develop three-armed triazole compounds

Fragment-based drug discovery is a valuable tool in hit identification, as well as the combination of different small fragments showing a minimal binding activity against biological receptors or enzymes to give merged hits. A high number of fragments on the same scaffold improve the probability to find a candidate showing single- or multi-target affinities. A rapid and versatile approach for synthesizing libraries of densely fragment-functionalized scaffolds is reported. Many fragments were assembled in few steps around a triazole ring starting from amino alcohols and other readily available building blocks. A binding assay against integrin α_vβ₃ was used as a test-bed in order to demonstrate the potential of such an approach in hit discovery strategies.     

Perfluorocarbon-hydrocarbons self-assembly: halogen bonding mediated intermolecular recognition

Halogen bonding is discussed as an interaction that is capable of overcoming the reluctance shown by fluorinated compounds towards interactions with hydrocarbons. This non-covalent interaction is sufficiently strong to enact formation of supramolecular architectures where perfluorocarbons, hydrocarbons, and inorganic salts are self-assembled. Examples are discussed which exemplify the consistency and versatility of this interaction in affording numerous and structurally different hybrid materials. The importance of fluorine in determining the overall packing of the formed architectures is also highlighted.     

Relation between configurational entropy and relaxation dynamics of glass-forming systems under volume and temperature reduction

The structural relaxation dynamics of two molecular glass-forming systems have been analyzed by means of dielectric spectroscopy, under cooling and compression conditions. The relation of the dynamic slowing down with the reduction of the configurational entropy, S_C, as predicted by Adam and Gibbs (AG), was also investigated. As S_C is not directly accessible by experiments, it was estimated, following a common procedure in literature, from the excess entropy S_exc of the supercooled liquid with respect to the crystal, determined from calorimetric and expansivity measurements over the same T–P range of dynamics investigation. The AG relation, predicting linear dependence between the logarithmic of structural relaxation time and the reciprocal of the product of temperature with configurational entropy, was successfully tested. Actually, a bilinear relation between S_exc and S_C was found, with different proportionality factors in isothermal and isobaric conditions. Using such results, we derived an equation for predicting the pressure dependence of the glass transition temperature, in good accordance with the experimental values in literature.     

“Push‐pull” supramolecular chromophores supported on cyclopolymers

Well‐defined macromolecules have been obtained through free‐radical cyclopolymerization and cyclocopolymerization of difunctional and acrylic‐like monomers, which contained “push‐pull” supramolecular chromophores, able to form 1:1 complexes with Eu³⁺ ions in solution. The monomeric molecular modules are built around bismalonate crown ethers in a convergent fashion, in which one of the malonate moiety is derivatized as the ylidene malonate push‐pull fragment, and the other malonate moiety is elaborated to introduce two polymerizable and acrylic‐like substituents. The free‐radical induced cyclopolymerization of these monomers, or their cyclocopolymerization with UV/Vis “silent” but structurally related monomers, afforded macromolecular architectures characterized by GPC, NMR and DSC techniques. UV/Vis titration studies, performed with Eu(OTf)₃ as the supramolecular probe, revealed how adjacent chromophores within the polymeric backbone are virtually independent from each other, and how the binding ability towards the probe of these multivalent, highly packed cyclopolymeric architectures, although reduced, is still clearly detectable. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5202–5213, 2008     

Convergence to the Barenblatt Solution for the Compressible Euler Equations with Damping and Vacuum

We study the asymptotic behavior of a compressible isentropic flow through a porous medium when the initial mass is finite. The model system is the compressible Euler equation with frictional damping. As t, the density is conjectured to obey the well-known porous medium equation and the momentum is expected to be formulated by Darcys law. In this paper, we give a definite answer to this conjecture without any assumption on smallness or regularity for the initial data. We prove that any L weak entropy solution to the Cauchy problem of damped Euler equations with finite initial mass converges, strongly in L^p with decay rates, to matching Barenblatts profile of the porous medium equation. The density function tends to the Barenblatts solution of the porous medium equation while the momentum is described by Darcys law.This revised version was published in April 2005. The volume number has now been inserted into the citation line.     

On the Finite Energy Weak Solutions to a System in Quantum Fluid Dynamics

In this paper we consider the global existence of weak solutions to a class of Quantum Hydrodynamics (QHD) systems with initial data, arbitrarily large in the energy norm. These type of models, initially proposed by Madelung [44], have been extensively used in Physics to investigate Superfluidity and Superconductivity phenomena [19,38] and more recently in the modeling of semiconductor devices [20] . Our approach is based on various tools, namely the wave functions polar decomposition, the construction of approximate solution via a fractional steps method which iterates a Schrödinger Madelung picture with a suitable wave function updating mechanism. Therefore several a priori bounds of energy, dispersive and local smoothing type, allow us to prove the compactness of the approximating sequences. No uniqueness result is provided.