Electronic Structure of Pentagonal Carbon Nanocones: An ab Initio Study.

In this work, we investigate the electronic structure of a particular class of carbon nanocones having a pentagonal tip and symmetry. The ground-state nature of the wave function for these structures can be predicted by the recently proposed generalized Hückel rule that extends the original Hückel rule for annulenes to this class of carbon nanocones. In particular, the structures here considered can be classified as closed-shell or anionic/cationic closed-shells, depending on the geometric characteristics of the cone.

Solution to the Thomson Problem for Clifford Tori with an Application to Wigner Crystals.

In its original version, the Thomson problem consists of the search for the minimum-energy configuration of a set of point-like electrons that are confined to the surface of a two-dimensional sphere () that repel each other according to Coulomb's law, in which the distance is the Euclidean distance in the embedding space of the sphere, i.e., .

Mapping of Hückel zigzag carbon nanotubes onto independent polyene chains: Application to periodic nanotubes.

The electric polarizability and the spread of the total position tensors are used to characterize the metallic vs insulator nature of large (finite) systems. Finite clusters are usually treated within the open boundary condition formalism. This introduces border effects, which prevent a fast convergence to the thermodynamic limit and can be eliminated within the formalism of periodic boundary conditions.

Clifford Boundary Conditions: A Simple Direct-Sum Evaluation of Madelung Constants.

We propose a simple direct-sum method for the efficient evaluation of lattice sums in periodic solids. It consists of two main principles: (i) the creation of a supercell that has the topology of a Clifford torus, which is a flat, finite, and borderless manifold; (ii) the renormalization of the distance between two points on the Clifford torus by defining it as the Euclidean distance in the embedding space of the Clifford torus. Our approach does not require any integral transformations nor any renormalization of the charges.

3D optical detection in radiodosimetry: EasyDosit hydrogel characterization.

In this study the spectrophotometric behaviour of gelatin-based hydrogels, in the presence and absence of dyes, was studied. The aim was to formulate equivalent-tissue phantoms to be used as 3D-dosimeter, suitable for Optical Computed Tomography (OCT). The hydrogels show good transparency and good stability of baseline optical density and, in the presence of dye, the response of optical density as a function of concentration was higher than in aqueous solution.

The Electronic Structure of Beryllium Chains.

We present an ab initio theoretical study of quasi one-dimensional beryllium chains, Be , from an electronic structure perspective for N = 3, 4,···, 12. In particular, linear and cyclic systems were compared by using high-quality coupled-cluster formalism. Both linear and cyclic species were found to be local minima on the corresponding potential energy surface, for all the considered values of N.

Copper(II) interactions with non-steroidal anti-inflammatory agents. III--3-Methoxyanthranilic acid as a potential *OH-inactivating ligand: a quantitative investigation of its copper handling role in vivo.

Pharmacological activities of copper(II) complexes are a direct function of the nature of their ligands associated with the metal ion in vivo. Some of these, defined as *OH-inactivating ligands (G. Berthon, Agents Actions 39 (1993) 210-217), may act as specific "lures" for hydroxyl radicals at inflammatory sites and behave as pseudo-catalase-like agents.

Aluminum speciation studies in biological fluids. Part 9. A quantitative investigation of aluminum(III)-glutamate complex equilibria and their potential implications for aluminum metabolism and toxicity.

As a nonessential element, aluminum is likely to be toxic both at low usual dietary levels in the long run (chronic toxicity) and at high therapeutic levels in shorter periods of time (acute toxicity). In both situations, aluminum toxicity is a direct function of aluminum bioavailability, which is itself dependent on Al(3+) solubility and charge neutralization. Dietary acids, by their intrinsic acidity and coordinating capacity, can extend the pH range, thus the section of the gastrointestinal tract, within which the Al(3+) ion remains soluble, and also help Al(3+) diffusion across the intestinal epithelium through the formation of neutral complex species.