The use of the generator coordinate method for designing basis set. Application to oxo-diperoxo molybdenum complexes

The molecular and electronic structures of MoO(O(2))(2) (1), MoO(O(2))(2)(OPY) (2) and MOO(O(2))(2)(OPY)(H(2)O) (3) complexes were investigated at the Hartree-Fock and density functional method (B3LYP) calculation levels. The generator coordinate method (GCM) has been used to design basis sets that properly represent the electronic density on the Mo and O atoms for all electron calculations, while a variant of the GCM method has been employed to design a valence basis set for the Mo atom for the pseudopotential calculations. Compound 1 adopts a distorted tetragonal pyramid structure, where the four peroxo oxygen atoms are located in the same plane, which is perpendicular to the axis defined by the Mo and oxo oxygen atoms. An analysis based upon the geometrical and electronic parameters and the vibrational frequencies renders that 1 can be described as two peroxide fragments bonded to the MoO moiety. 2 and 3 complexes are bipyramidal pentagonal structures, with the OPy ligand occupying a quasi-equatorial position in the same plane as the two peroxo triangles while the H(2)O ligand is situated trans to the oxo group in 3. A comparison between theoretical and experimental results for the geometry and vibrational frequencies of 3 complex shows good agreement. The relationship between the reactivity of 1, 2 and 3 complexes and their coordination number has been established by analyzing the values of the vibrational frequencies, frontier molecular orbitals and the values of electron affinities. (C) 2002 Elsevier Science B.V. All rights reserved.58925126

Hemangioendotelioma epitelióide de pleura Epithelioid hemangioendothelioma of the pleura

Relata-se o caso de um paciente exposto profissionalmente a asbesto por dez anos e portador de um tumor pleural muito raro, o hemangioendotelioma epitelióde. O paciente apresentava derrame pleural serohemorrágico, sem evidência de células neoplásicas e com predomínio de linfócitos. A biópsia pleural por agulha revelou processo inflamatório crônico inespecífico, com áreas de tecido mixóide. A videotoracoscopia mostrou nódulos difusos nas pleuras parietal e visceral. A biópsia revelou neoplasia mesenquimal e eram semelhantes às áreas focais observadas na primeira biópsia. O estudo imunohistoquímico demonstrou a presença dos marcadores vasculares CD31, CD34 e Fator VIII, caracterizando a origem vascular do tumor. O paciente foi tratado com cisplatina e ectoposide, tendo o óbito ocorrido três meses após o diagnóstico.<br>Epithelioid hemangioendothelioma (EHE), a very uncommon pleural tumor, was diagnosed in a 61-year-old man with work-related exposure to asbestos. Serohemorrhagic pleural effusion was diagnosed in the work-up of this patient, whose complaints were chest pain and weight loss. A lymphocytic predominance was present in the effusion, but no malignant cells were seen; pleural needle biopsy disclosed only a non-specific inflammatory process. Video thoracoscopy revealed nodules in parietal and visceral pleurae. A biopsy revealed a mesenchymal neoplasm; vascular markers CD 31, CD 34 and VIII factor were present; therefore, diagnosis of HE was accepted. The tumor was not responsive to cisplatin or etoposide and the patient died 3 months after the diagnosis

Litter materials and the incidence of carcass lesions in broilers chickens

The aim of this study was to evaluate the effects of different litter materials on litter compaction, broiler feathering and the incidence of carcass lesions. In the experiment, 3240 one-day-old Ross® chicks were selected by sex and distributed according to a completely randomized experimental design in a 2 x 6 factorial arrangement (two sex and six litter materials). The following litter materials were used: wood shavings, rice husks, chopped Napier grass, 50% sugar cane bagasse plus 50% wood shavings, 50% sugar cane bagasse plus 50% rice husks, and pure sugar cane bagasse. Litter compaction was weekly assessed using a penetrometer. On days 21, 35 and 42 of the experimental period, feathering on the back and legs was scored according to a 0 - 10 scale. On day 42, birds were slaughtered and the presence of bruises, scratches and footpad lesions was recorded. Litter material had no effect on bird feathering. Carcass lesions (scratches, bruises and footpad lesions) were influenced by the litter material evaluated. Birds reared on sugarcane bagasse and chopped Napier grass presented more scratches, bruises and footpad lesions than the others. Dermatitis was more evident in birds reared on sugarcane bagasse, chopped Napier grass and the combination of litter materials. It was found that males presented higher incidence of dermatitis and footpad lesions than females. Each litter material presented different compaction degrees, which increased along the experimental period. Sugarcane bagasse, chopped Napier grass and the combination of bedding materials presented the highest degree of compaction, compared with wood shavings and rice husks

Fusion–fission experiments in Aphidius: evolutionary split without isolation in response to environmental bimodality

Studying host-based divergence naturally maintained by a balance between selection and gene flow can provide valuable insights into genetic underpinnings of host adaptation and ecological speciation in parasites. Selection-gene flow balance is often postulated in sympatric host races, but direct experimental evidence is scarce. In this study, we present such evidence obtained in host races of Aphidius ervi, an important hymenopteran agent of biological control of aphids in agriculture, using a novel fusion–fission method of gene flow perturbation. In our study, between-race genetic divergence was obliterated by means of advanced hybridisation, followed by a multi-generation exposure of the resulting genetically uniform hybrid swarm to a two-host environment. This fusion–fission procedure was implemented under two contrasting regimes of between-host gene flow in two replicated experiments involving different racial pairs. Host-based genetic fission in response to environmental bimodality occurred in both experiments in as little as six generations of divergent adaptation despite continuous gene flow. We demonstrate that fission recovery of host-based divergence evolved faster and hybridisation-induced linkage disequilibrium decayed slower under restricted (6.7%) compared with unrestricted gene flow, directly pointing at a balance between gene flow and divergent selection. We also show, in four separate tests, that random drift had no or little role in the observed genetic split. Rates and patterns of fission divergence differed between racial pairs. Comparative linkage analysis of these differences is currently under way to test for the role of genomic architecture of adaptation in ecology-driven divergent evolution