304 research outputs found
Rapid thermal annealing effects on the structural properties and density of defects in SiO2 and SiNx:H films deposited by electron cyclotron resonance
El caso IRICE: un espacio socio-técnico para investigación y diseminación de conocimiento
Esta comunicación presenta aspectos significativos del diseño y desarrollo de un espacio institucional virtual multiplataforma de una unidad ejecutora de investigación en el campo de las Ciencias de la Educación. La arquitectura propuesta tiene por objetivo tanto la conformación y promoción de redes socio-técnicas en contextos investigativos, como la promoción de estrategias que transformen paulatinamente las prácticas participativas de la comunidad académica, consolidando el vínculo con la ciudadanía en su conjunto.
El marco teórico-metodológico se fundamentó en la perspectiva de los Dispositivos Hipermediales Dinámicos, atendiendo a condiciones de inclusión social y a la implementación de tecnologías de código abierto considerando los marcos jurídicos del estado argentino.Sociedad Argentina de Informática e Investigación Operativa (SADIO
Efficient solution of the non-linear Reynolds equation for compressible fluid using the finite element method
El caso IRICE: un espacio socio-técnico para investigación y diseminación de conocimiento
Esta comunicación presenta aspectos significativos del diseño y desarrollo de un espacio institucional virtual multiplataforma de una unidad ejecutora de investigación en el campo de las Ciencias de la Educación. La arquitectura propuesta tiene por objetivo tanto la conformación y promoción de redes socio-técnicas en contextos investigativos, como la promoción de estrategias que transformen paulatinamente las prácticas participativas de la comunidad académica, consolidando el vínculo con la ciudadanía en su conjunto.
El marco teórico-metodológico se fundamentó en la perspectiva de los Dispositivos Hipermediales Dinámicos, atendiendo a condiciones de inclusión social y a la implementación de tecnologías de código abierto considerando los marcos jurídicos del estado argentino.Sociedad Argentina de Informática e Investigación Operativa (SADIO
Elucidating the real-time Ag nanoparticle growth on alpha-Ag2WO4 during electron beam irradiation: experimental evidence and theoretical insights
FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORWhy and how Ag is formed when electron beam irradiation takes place on alpha-Ag2WO4 in a vacuum transmission electron microscopy chamber? To find an answer, the atomic-scale mechanisms underlying the formation and growth of Ag on alpha-Ag2WO4 have been investigated by detailed in situ transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) studies, density functional theory based calculations and ab initio molecular dynamics simulations. The growth process at different times, chemical composition, size distribution and element distribution were analyzed in depth at the nanoscale level using FE-SEM, operated at different voltages (5, 10, 15, and 20 kV), and TEM with energy dispersive spectroscopy (EDS) characterization. The size of Ag nanoparticles covers a wide range of values. Most of the Ag particles are in the 20-40 nm range. The nucleation and formation of Ag on alpha-Ag2WO4 is a result of structural and electronic changes in the AgOx (x = 2,4, 6, and 7) clusters used as constituent building blocks of this material, consistent with metallic Ag formation. First principle calculations point out that Ag-3 and Ag-4-fold coordinated centers, located in the sub-surface of the (100) surface, are the most energetically favorable to undergo the diffusion process to form metallic Ag. Ab initio molecular dynamics simulations and the nudged elastic band (NEB) method were used to investigate the minimum energy pathways of these Ag atoms from positions in the first slab layer to outward sites on the (100) surface of alpha-Ag2WO4. The results point out that the injection of electrons decreases the activation barrier for this diffusion step and this unusual behavior results from the presence of a lower energy barrier process.Why and how Ag is formed when electron beam irradiation takes place on alpha-Ag2WO4 in a vacuum transmission electron microscopy chamber? To find an answer, the atomic-scale mechanisms underlying the formation and growth of Ag on alpha-Ag2WO4 have been investigated by detailed in situ transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) studies, density functional theory based calculations and ab initio molecular dynamics simulations. The growth process at different times, chemical composition, size distribution and element distribution were analyzed in depth at the nanoscale level using FE-SEM, operated at different voltages (5, 10, 15, and 20 kV), and TEM with energy dispersive spectroscopy (EDS) characterization. The size of Ag nanoparticles covers a wide range of values. Most of the Ag particles are in the 20-40 nm range. The nucleation and formation of Ag on alpha-Ag2WO4 is a result of structural and electronic changes in the AgOx (x = 2,4, 6, and 7) clusters used as constituent building blocks of this material, consistent with metallic Ag formation. First principle calculations point out that Ag-3 and Ag-4-fold coordinated centers, located in the sub-surface of the (100) surface, are the most energetically favorable to undergo the diffusion process to form metallic Ag. Ab initio molecular dynamics simulations and the nudged elastic band (NEB) method were used to investigate the minimum energy pathways of these Ag atoms from positions in the first slab layer to outward sites on the (100) surface of alpha-Ag2WO4. The results point out that the injection of electrons decreases the activation barrier for this diffusion step and this unusual behavior results from the presence of a lower energy barrier process.17753525359FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP [2013/07296-2, 2012/14468-1, 2010/16970-0, 2013/02032-7]CNPq [573636/2008-7, 150753/2013-6]CAPES [088/2013]2010/16970-02012/14468-12013/02032-72013/07296-2573636/2008-7150753/2013-6088/2013The authors are grateful to Prometeo/2009/053 (GeneralitatValenciana), Ministerio de Economia y Competitividad (Spain), CTQ2012-36253-C03-02, Spanish Brazilian program (PHB2009-0065-PC), FAPESP (Project 2013/07296-2) (Project 2012/14468-1) (Project 2010/16970-0), grant (2013/02032-7), CAPES and CNPq (Project 573636/2008-7, Grant 150753/2013-6) and CAPES (Project 088/2013) for financially supporting this research. Most of the calculations were performed using IFGW-UNICAMP computer facilities and the National Center for High Performance Computing in São Paulo (CENAPAD-SP). We also acknowledge the Servei Informática, Universitat Jaume I, for the generous allotment of computer time
Frozen cancellous bone allografts: positive cultures of implanted grafts in posterior fusions of the spine
We have carried out a study on the behaviour pattern of implanted allografts
initially stored in perfect conditions (aseptically processed, culture-negative
and stored at -80 degrees C) but which presented positive cultures at the
implantation stage. There is no information available on how to deal with this
type of situation, so our aim was to set guidelines on the course of action which
would be required in such a case. This was a retrospective study of 112 patients
who underwent a spinal arthrodesis and in whom a total of 189 allograft pieces
were used. All previous bone and blood cultures and tests for hepatitis B and C,
syphilis and HIV (via PCR techniques) were negative. The allografts were stored
by freezing them at -80 degrees C. A sample of the allograft was taken for
culture in the operating theatre just before its implantation in all cases. The
results of the cultures were obtained 3-5 days after the operation. There were 22
allografts with positive culture results (12%) after implantation. These
allografts were implanted in 16 patients (14%). Cultures were positive for
staphylococci coagulase negative (ECN) in 10 grafts (46%), Pseudomonas stutzeri
in two grafts (9%), Corynebacterium jeikeium in two grafts (9%), staphylococci
coagulase positive in two grafts (9%) and for each of the following organisms in
one case each (4%): Corynebacterium spp., Actinomyces odontolyticus,
Streptococcus mitis, Peptostreptococcus spp., Rhodococcus equi and Bacillus spp.
No clinical infection was seen in any of these patients. Positive cultures could
be caused by non-detected contamination at harvesting, storing or during
manipulation before implantation. The lack of clinical signs of infection during
the follow-up of our patients may indicate that no specific treatment different
from our antibiotic protocol is required in the case of positive culture results
of a graft piece after implantation
Optical and structural properties of SiOxNyHz films deposited by electron cyclotron resonance and their correlation with composition
Scandium oxide deposited by high-pressure sputtering for memory devices: Physical and interfacial properties
Optical spectroscopic study of the SiN∕HfO2 interfacial formation during rf sputtering of HfO2
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