Structure and dynamics in liquid bismuth and Bi(n) clusters: a density functional study.

Density functional/molecular dynamics simulations with more than 500 atoms have been performed on liquid bismuth at 573, 773, 923, and 1023 K and on neutral Bi clusters with up to 14 atoms. There are similar structural patterns (coordination numbers, bond angles, and ring patterns) in the liquid and the clusters, with significant differences from the rhombohedral crystalline form. We study the details of the structure (structure factor, pair, and cavity distribution functions) and dynamical properties (vibration frequencies, diffusion constants, power spectra), and compare with experimental results where available.

Density functional study of Cu(2+)-phenylalanine complex under micro-solvation environment.

We present an atomistic study carried out using density functional calculations including structural relaxations and Car-Parrinello Molecular Dynamics (CPMD) simulations, aiming to investigate the structures of phenylalanine-copper (II) ([Phe-Cu](2+)) complexes and their micro-solvation processes. The structures of the [Phe-Cu](2+) complex with up to four water molecules are optimized using the B3LYP/6-311++G** model in gas phase to identify the lowest energy structures at each degree of solvation (n=0-4). It is found that the phenylalanine appears to be in the neutral form in isolated and mono-hydrated complexes, but in the zwitterionic form in other hydrated complexes (with n≥2).

Solvent effect on cation-π interactions with Al3+.

Cation-π interactions are known to be one of the strongest noncovalent forces in the gas phase, but they rarely occur in a fully solvated environment. The present work used two different ab initio molecular dynamics-based approaches to describe the correlation between the strength of the cation-π interactions and the number of water molecules surrounding the cation. Five different complexes between an aluminum cation and different molecules containing aromatic rings were studied, and the degree of hydration of each complex was varied.

Ab initio study of microsolvated Al3+-aromatic amino acid complexes.

The systematic microhydration of Al(3+)-aromatic amino acid complexes is studied by both B3LYP/G03 and PBE/CPMD methods, considering the different binding sites available. The binding affinity of water molecules together with the structural and thermochemical changes triggered by the solvation of the metal are discussed, which are found to be dominated by the charge and size of the metal cation, yielding a very subtle equilibrium between the steric hindrance and the charge transfer to the metal. Some structures previously seen to be unfavored in the gas phase are stabilized upon microhydration, without the need of including bulk solvent effects.

Renal transplant in children with previous inferior vena cava thrombosis.

Our experience with renal transplantation in children with inferior vena cava thrombosis is presented in this study. Of the 238 children who have received renal transplants at our institution, four had IVC thrombosis (discovered during pretransplant evaluation: three patients; found at surgery: one patient). The pretransplant US evaluation diagnosis of IVC thrombosis in three patients was confirmed by transjugular retrograde cavography.