Thermal stability of reactive sputtered tungsten oxide coatings

The thermal stability of different W-O coatings, W100, W90O10, W54O46, W30O70 and W25O75, were studied by in-situ X-ray diffraction at elevated temperatures up to 900 °C. The coatings were deposited by DC reactive magnetron sputtering from a pure tungsten target in an Ar + O2 atmosphere onto Fecralloy alloy. The evolution of the structure of the coatings was studied in both protective and oxidant atmospheres. Three groups of films were identified: (1) W25O75 which showed structural evolution following the W-O phase diagram; (2) amorphous O-deficient WO3 whose structure followed the W-O phase diagram either as WO3 or as its chemical composition depending on annealing in oxidant or protective atmospheres, respectively; and (3) low O-content crystalline films that oxidized from 500 °C.http://www.sciencedirect.com/science/article/B6TVV-4MV74W9-1/1/f13fd19171ebf6554fff185464ae87e

Hábitos de estudo e estilos de aprendizagem no ensino público e privado universitário

O objectivo deste artigo é examinar os hábitos de estudo e os estilos de aprendizagem entre os alunos do primeiro ano que frequentam universidades públicas e compará-los com os que frequentam universidades privadas, tendo em vista identificar os atributos desses estudantes que podem influenciar a adopção de um ou outro estilo. A compreensão destas diferenças por parte dos professores permite uma maior probabilidade de se orientarem para a excelência do ensino, com consequentes melhorias na aprendizagem e no sucesso académico dos estudantes.FC

Genetic Diversity of norA, Coding for a Main Efflux Pump of Staphylococcus aureus

Funding Information: This work was partially supported by Fundação para a Ciência e a Tecnologia (FCT, Portugal), through funds to GHTM – UID/Multi/04413/2013. SC was supported by grant SFRH/BPD/97508/2013 from FCT, Portugal. TC was funded by the Medical Research Council United Kingdom (Grant Nos. MR/K000551/1, MR/M01360X/1, MR/N010469/1, and MR/R020973/1) and BBSRC United Kingdom (BB/R013063/1). BS was funded by the Medical Research Council United Kingdom (Grant No. MR/N010469/1). Publisher Copyright: © 2007 - 2019 Frontiers Media S.A. All Rights Reserved.NorA is the best studied efflux system of Staphylococcus aureus and therefore frequently used as a model for investigating efflux-mediated resistance in this pathogen. NorA activity is associated with resistance to fluoroquinolones, several antiseptics and disinfectants and several reports have pointed out the role of efflux systems, including NorA, as a first-line response to antimicrobials in S. aureus. Genetic diversity studies of the gene norA have described three alleles; norAI, norAII and norAIII. However, the epidemiology of these alleles and their impact on NorA activity remains unclear. Additionally, increasing studies do not account for norA variability when establishing relations between resistance phenotypes and norA presence or reported absence, which actually corresponds, as we now demonstrate, to different norA alleles. In the present study we assessed the variability of the norA gene present in the genome of over 1,000 S. aureus isolates, corresponding to 112 S. aureus strains with whole genome sequences publicly available; 917 MRSA strains sourced from a London-based study and nine MRSA isolates collected in a major Hospital in Lisbon, Portugal. Our analyses show that norA is part of the core genome of S. aureus. It also suggests that occurrence of norA variants reflects the population structure of this major pathogen. Overall, this work highlights the ubiquitous nature of norA in S. aureus which must be taken into account when studying the role played by this important determinant on S. aureus resistance to antimicrobials.publishersversionpublishe

Prediction of diffusion coefficients of chlorophenols in water by computer simulation

Intra-diffusion coefficients of seven chlorophenols (2-chlorophenol, 3-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,6-dichlorophenol, 2,4,6-dichlorophenol and pentachlorophenol) in water were determined by computer simulation (molecular dynamics) for dilute solutions at three different temperatures and the corresponding mutual diffusion coefficients estimated. The mutual diffusion coefficients of 2-chlorophenol in water agree with the available experimental results from the literature for all the temperatures studied. From the dependence of the diffusion coefficients on temperature, diffusion activation energies were estimated for all the solutes inwater. Analyzing the radial distribution functions and spatial distribution functions of water around chlorophenols sites enable a discussion about intermolecular interactions (dominated by hydrogen bonding) between solute and solvent and its importance on the relative magnitude of diffusion coefficients. Finally the mutual diffusion coefficients obtained by simulation were correlated by the well-known Wilke–Chang equation

Perceptions and evaluations of front-line health workers regarding the Brazilian National Program for Improving Access and Quality to Primary Care (PMAQ): a mixed-method approach

Although it is well known that a successful implementation depends on the front-liners’ knowledge and participation, as well as on the organizational capacity of the institutions involved, we still know little about how front-line health workers have been involved in the implementation of the Brazilian National Program for Improving Access and Quality to Primary Care (PMAQ). This paper develops a contingent mixed-method approach to explore the perceptions of front-line health workers - managers, nurses, community health workers, and doctors - regarding the PMAQ (2nd round), and their evaluations concerning health unit organizational capacity. The research is guided by three relevant inter-related concepts from implementation theory: policy knowledge, participation, and organizational capacity. One hundred and twenty-seven health workers from 12 primary health care units in Goiânia, Goiás State, Brazil, answered semi-structured questionnaires, seeking to collect data on reasons for adherence, forms of participation, perceived impact (open-ended questions), and evaluation of organizational capacity (score between 0-10). Content analyses of qualitative data enabled us to categorize the variables “level of perceived impact of PMAQ” and “reasons for adhering to PMAQ”. The calculation and aggregation of the means for the scores given for organizational capacity enabled us to classify distinct levels of organizational capacity. We finally integrated both variables (Perceived-Impact and Organizational-Capacity) through cross-tabulation and the narrative. Results show that nurses are the main type of professional participating. The low organizational capacity and little policy knowledge affected workers participation in and their perceptions of the PMAQ

A rapid and simple method for constructing stable mutants of Acinetobacter baumannii

<p>Abstract</p> <p>Background</p> <p><it>Acinetobacter baumannii </it>is a multidrug-resistant bacterium responsible for nosocomial infections in hospitals worldwide. Study of mutant phenotypes is fundamental for understanding gene function. The methodologies developed to inactivate <it>A. baumannii </it>genes are complicated and time-consuming; sometimes result in unstable mutants, and do not enable construction of double (or more) gene knockout mutant strains of <it>A. baumannii</it>.</p> <p>Results</p> <p>We describe here a rapid and simple method of obtaining <it>A. baumannii </it>mutants by gene replacement via double crossover recombination, by use of a PCR product that carries an antibiotic resistance cassette flanked by regions homologous to the target locus. To demonstrate the reproducibility of the approach, we produced mutants of three different chromosomal genes (<it>omp33</it>, <it>oxyR</it>, and <it>soxR</it>) by this method. In addition, we disrupted one of these genes (<it>omp33</it>) by integration of a plasmid into the chromosome by single crossover recombination, the most widely used method of obtaining <it>A. baumannii </it>mutants. Comparison of the different techniques revealed absolute stability when the gene was replaced by a double recombination event, whereas up to 40% of the population reverted to wild-type when the plasmid was disrupting the target gene after 10 passages in broth without selective pressure. Moreover, we demonstrate that the combination of both gene disruption and gene replacement techniques is an easy and useful procedure for obtaining double gene knockout mutants in <it>A. baumannii</it>.</p> <p>Conclusions</p> <p>This study provides a rapid and simple method of obtaining stable mutants of <it>A. baumannii </it>free of foreign plasmidic DNA, which does not require cloning steps, and enables construction of multiple gene knockout mutants.</p

Preservação de Colletotrichum graminicola, agente causal da podridão do colmo do milho.

Suplemento. Edição dos resumos do 44º Congresso Brasileiro de Fitopatologia, 2011, Bento Gonçalves. Resumo 548