Structures, stabilities and aromatic properties of endohedrally transition metal doped boron clusters M@B, M = Sc and Ti: a theoretical study.

A genetic search algorithm in conjunction with density functional theory calculations was used to determine the lowest-energy minima of the pure B22 cluster and thereby to evaluate the capacity of its isomers to form endohedrally doped cages with two transition metal atoms M (M = Sc and Ti). An important charge transfer from metal atoms M to the boron cage takes place, stabilizing the endohedral compounds, as predicted with the genetic algorithm implemented. High-level coupled-cluster theory CCSD(T) calculations were carried out to confirm that the structures found are the lowest-energy isomers.

Stability of AuAg (m + n = 1-6) clusters supported on a F-center MgO(100) surface.

A theoretical study has been performed for deposited AumAgn (m + n = 1-6) clusters. The combined use of the Mexican Enhanced Genetic Algorithm (MEGA) and Density Functional Theory (DFT) calculations allows us to explore the potential energy surface and therefore, find the global minimum configuration for each composition. We have performed calculations of clusters deposited on defects (oxygen vacancies) known as F centers on MgO (100) surfaces.

Social interactions predict genetic diversification: an experimental manipulation in shorebirds.

Mating strategy and social behavior influence gene flow and hence affect levels of genetic differentiation and potentially speciation. Previous genetic analyses of closely related plovers spp. found strikingly different population genetic structure in Madagascar: Kittlitz's plovers are spatially homogenous whereas white-fronted plovers have well segregated and geographically distinct populations.

A comparative study of AumRhn (4 ≤ m + n ≤ 6) clusters in the gas phase versus those deposited on (100) MgO.

A comparative theoretical study has been performed of the gas phase and deposited AumRhn (4 ≤ m + n ≤ 6) clusters. The combined use of a genetic algorithm and Density Functional Theory (DFT) calculations allows us to explore the potential energy surface and, therefore, find efficiently and automatically the global minimum configuration for each composition. Our results show interesting effects on the geometries of the clusters on deposition.

Ab initio and anion photoelectron study of AunRhm (n = 1-7, m = 1-2) clusters.

Anion photoelectron spectroscopy (PES) and ab initio calculations have been used to identify the unique structural, electronic, and magnetic properties of both neutral and anionic binary AunRhm (n = 1-7 and m = 1-2) clusters in vacuo. Negative ion photoelectron spectra are presented with electron binding energies measured up to 3.493 eV.

Joint photoelectron and theoretical study of (Rh(m)Co(n))⁻ (m=1-5, n=1-2) cluster anions and their neutral counterparts.

Anion photoelectron spectroscopic experiments and calculations based on density functional theory have been used to investigate and uniquely identify the structural, electronic, and magnetic properties of both neutral and anionic (Rh(m)Co(n)) and (Rh(m)Co(n))(-) (m=1-5, n=1-2) clusters, respectively. Negative ion photoelectron spectra are presented for electron binding energies up to 3.493 eV.

Patients' perspective in Chilean primary care: a questionnaire validation study.

Objective: The aim of this study was to adapt and validate an instrument for assessing quality of care from the patients' perspective in the context of Chilean primary care.

Methods: The 'Health Centre Assessment Questionnaire' is made up of six multiple-item scales and two single-item scales addressing eight key areas of primary care activity. A further two single-item scales ask about the overall satisfaction and the way in which the centre deals with patients' health issues.

[In vitro effect of caffeine on internal mammary artery rings used in cardiac revascularization surgery].

Introduction: The vasodilator effect of caffeine in animal models arteries has been demonstrated previously. However, studies with the same methodology using human arteries in vitro have not been performed.

Objectives: The in vitro vasoactive effects of caffeine was evaluated on human internal mammary arteries.

Retail survey of Brazilian milk and Minas frescal cheese and a contaminated dairy plant to establish prevalence, relatedness, and sources of Listeria monocytogenes isolates.

A study was designed to recover Listeria monocytogenes from pasteurized milk and Minas frescal cheese (MFC) sampled at retail establishments (REs) and to identify the contamination source(s) of these products in the corresponding dairy processing plant. Fifty milk samples (9 brands) and 55 MFC samples (10 brands) were tested from REs located in Juiz de Fora, Minas Gerais, Brazil. All milk samples and 45 samples from 9 of 10 MFC brands tested negative for L.

H2O nucleation around Au+.

First principles electronic structure calculations have been carried out to investigate the ground state geometry, electronic structure, and the binding energy of [Au(H2O)n]+ clusters containing up to 10 H2O molecules. It is shown that the first coordination shell of Au+ contains two H2O molecules forming a H2O-Au+-H2O structure with C2 symmetry. Subsequent H2O molecules bind to the previous H2O molecules forming stable and fairly rigid rings, each composed of 4 H2O molecules, and leading to a dumbbell structure at [Au(H2O)8]+.

Electron states in a lattice of Au nanoparticles: the role of strain and functionalization.

We make use of first-principles calculations to study the effects of functionalization and compression on the electronic properties of 2D lattices of Au nanoparticles. We consider Au38 particles capped by methylthiol molecules and possibly functionalized by the dithiolated conjugated molecules benzenedimethanethiol and benzenedicarbothialdehyde. We find that the nonfunctionalized lattices are insulating, with negligible band dispersions even for a compression of 20% of the lattice constant.