Tris(pyrone) chelates of Gd(III) as high solubility MRI-CA

Two tripodal, hexadentate pyrone-based chelators have been prepared. These ligands form stable, soluble complexes with gadolinium(III). The complexes show aqueous stability comparable to that of [Gd(DTPA)]2- at pH 7.4. Evaluation by relaxometry shows that these complexes have two inner-sphere water molecules and a very fast water exchange rate. The solution behavior of these complexes suggests that they may be attractive as high relaxivity, next-generation magnetic resonance imaging contrast agents.     

Taxonomical markers in two endemic plants of Sardinia: Verbascum conocarpum and Scrophularia trifoliata

The monoterpenoid composition of Verbascum conocarpum and Scrophularia trifoliata, both endemic plants of Sardinia, was examined. The main chemotaxonomic markers of Scrophulariaceae, the iridoids aucubin, verbascoside and catalpol, were isolated.     

Multicomponent synthesis of 3-heteroarylpropionic acids

A four component one-pot procedure (4-MC) was developed to assemble 3-heteroarylpropionic acids from commercially available materials. This new methodology affords the title compounds in high yields and without the use of chromatography. [reaction: see text]     

Vortex patterns in a superconducting-ferromagnetic rod

A superconducting rod with a magnetic moment on top develops vortices obtained here through 3D calculations of the Ginzburg–Landau theory. The inhomogeneity of the applied field brings new properties to the vortex patterns that vary according to the rod thickness. We find that for thin rods (disks) the vortex patterns are similar to those obtained in presence of a homogeneous magnetic field instead because they consist of giant vortex states. For thick rods novel patterns are obtained as vortices are curve lines in space that exit through the lateral surface.     

Vortex dynamics in mesoscopic superconducting square of variable surface

In this paper we apply the time dependent Ginzburg–Landau (TDGL) equations to the study of thin superconducting films of variable surfaces in the presence of an external applied magnetic field. We have made a systematic investigation of both the lower and upper critical fields as a function of the topological parameters which control the shape of the film surfaces. We also make a detailed investigation of the vortex dynamics as they nucleate into the sample.     

Bio-vaterite formation by glycoproteins from freshwater pearls

A 48 kDa acidic and putative calcium-binding glycoprotein was isolated from pearls of the freshwater mussel Hyriopsis cumingii. This protein was compared with a related 46 kDa polypeptide, obtained from the nacreous shell of the same species. Separation by two-dimensional gel electrophoresis revealed that the difference in molecular weight is due to the higher extent of glycosylation of the 48 kDa protein existing in pearls. Evidence is presented that the sugar moieties of the protein contribute to crystal growth, starting with the nucleation step. In in vitro precipitation experiments, the 48 kDa glycoprotein of pearls directed the formation of round-shaped vaterite crystals while the 46 kDa glycoprotein of shells promoted formation of small irregular calcite particles. Furthermore, both proteins, 48 kDa/46 kDa, comprised carbonic anhydrase activity that has been implicated in CaCO₃ formation. Thus, a function of the isolated glycoproteins in biomineralization is proposed together with the mechanism by which they can stabilize different calcium carbonate polymorphs.     

A Survey on the Differential and Symplectic Geometry of Linking Numbers

The aim of the present survey mainly consists in illustrating some recently emerged differential and symplectic geometric aspects of the ordinary and higher order linking numbers of knot theory, within the modern geometrical and topological framework, constantly referring to their multifaceted physical origins and interpretations. Lecture held in the Seminario Matematico e Fisico on May 2, 2005 Received: May 2006     

Catalytic Membranes and Membrane Reactors： An Integrated Approach to Catalytic Process with a High Efficiency and a Low Environmental Impact

The design of new heterogeneous photooxygenation systems able to employ visible light,oxygen,mild temperatures,and solvent with a low environmental impact has been investigated. In particular,the heterogenization of decatungstate (W10O4-32),a polyoxometalate with photocatalytic activity in oxidation reactions,has been carried out in polymeric membranes of polyvinylidenefluoride. The polymeric catalytic membranes prepared by phase inversion technique have been successfully applied in the aerobic mineralization of phenol in water,which was used as an example of organic pollutant. In order to evaluate the effect of the polymeric environment on the overall catalyst behavior,we have also heterogenized the decatungstate (opportunely functionalized) in perfluorinated membrane made of Hyflon. The photocatalytic composite membranes are characterized by different and tuneable properties depending on the nature of the polymeric micro-environment,in which the catalyst is confined. Moreover,the selective separation function of the membrane results in enhanced performance in comparison with homogeneous reactions.