Mycoplasma pneumonia : an unusual cause of acute myocarditis in childhood

Mycoplasma pneumoniae is primarily a respiratory pathogen but may affect exhibit a diverse range of presentations from asymptomatic infection to life threatening conditions. Myocarditis of varying severity is an unusual complication. We report a 6 year old with mycoplasma myocarditis, a rare age for such a presentation, and who responded well to treatment with no sequelae. Serological testing for Mycoplasma pneumoniae should be part of the routine work-up for myocarditis.peer-reviewe

Theoretical study of the mechanism of dry oxidation of 4H-SiC

Possible defect structures, arising from the interaction of O-2 molecules with an ideal portion of the SiC/SiO2 interface, have been investigated systematically using density functional theory. Based on the calculated total energies and assuming thermal quasiequilibrium during oxidation, the most likely routes leading to complete oxidation have been determined. The defect structures produced along these routes will remain at the interface in significant concentration when stopping the oxidation process. The results obtained for their properties are well supported by experimental findings about the SiC/SiO2 interface. It is found that carbon-carbon bonds can explain most of the observed interface states but not the high density near the conduction band of 4H-SiC

Structure and properties of ilmenite from first principles

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Defects in SiO2 as the possible origin of near interface traps in the SiC∕SiO2 system: A systematic theoretical study

A systematic study of the level positions of intrinsic and carbon defects in SiO2 is presented, based on density functional calculations with a hybrid functional in an alpha-quartz supercell. The results are analyzed from the point of view of the near interface traps (NIT), observed in both SiC/SiO2 and Si/SiO2 systems, and assumed to have their origins in the oxide. It is shown that the vacancies and the oxygen interstitial can be excluded as the origin of such NIT, while the silicon interstitial and carbon dimers give rise to gap levels in the energy range inferred from experiments. The properties of these defects are discussed in light of the knowledge about the SiC/SiO2 interface

Stability and Electronic Properties of TiO2 Nanostructures With and Without B and N Doping

We address one of the main challenges to TiO2-photocatalysis, namely band gap narrowing, by combining nanostructural changes with doping. With this aim we compare TiO2's electronic properties for small 0D clusters, 1D nanorods and nanotubes, 2D layers, and 3D surface and bulk phases using different approximations within density functional theory and GW calculations. In particular, we propose very small (R < 0.5 nm) but surprisingly stable nanotubes with promising properties. The nanotubes are initially formed from TiO2 layers with the PtO2 structure, with the smallest (2,2) nanotube relaxing to a rutile nanorod structure. We find that quantum confinement effects - as expected - generally lead to a widening of the energy gap. However, substitutional doping with boron or nitrogen is found to give rise to (meta-)stable structures and the introduction of dopant and mid-gap states which effectively reduce the band gap. Boron is seen to always give rise to n-type doping while depending on the local bonding geometry, nitrogen may give rise to n-type or p-type doping. For under coordinated TiO2 surface structures found in clusters, nanorods, nanotubes, layers and surfaces nitrogen gives rise to acceptor states while for larger clusters and bulk structures donor states are introduced

Aid, growth and peace: A comparative analysis.

yesThe paper examines patterns of post-conflict aid in a sample of 14 countries, with in-depth, qualitative analysis of seven cases (Bosnia, Cambodia, El Salvador, Nicaragua, Guatemala, Mozambique and Rwanda). The study takes previous work by Paul Collier and associates in this area as a starting point, but disaggregates the data by type of aid, time intervals, and historical period. The findings significantly qualify the Collier conclusion to the effect that donors respond to a CNN-effect in a dysfunctional manner by rushing in aid soon after a peace agreement is concluded and scaling back too soon. Rather, disaggregated analysis shows that post-war aid follows several patterns and can best be understood as strategic behavior designed to promote a range of economic and political objectives. This paper also questions the related policy recommendation of the Collier research on post-conflict aid, namely that post-conflict aid should be phased in so as to maximize economic growth on the grounds that this is important to sustain peace during the first post-conflict decade. Instead, this paper finds, aid strategies that demonstrate early and firm donor commitment to the new order are more likely to stabilize peace in the short run, and aid strategies that address the underlying sources of conflict are important to sustain peace in the longer run

First-principles calculations of the phase stability of TiO2

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Electronic structure of CaCuO2 from the B3LYP hybrid density functional

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