Spontaneous spinal epidural haematoma due to arteriovenous malformation in a child

Spontaneous spinal epidural haematoma (SSEH) is a rare clinical entity, especially in infants, in whom only a few cases have been reported. In a paediatric emergency setting, SSEH should be considered as part of the differential diagnosis for acute extremity weakness and paraesthesia. Epidural vascular malformations are often suspected in these cases but have rarely been demonstrated. The authors report herein a case of SSEH in a 9-year-old boy arising from an epidural vascular malformation. He initially presented with sudden intense cervicodorsal pain followed by hypotonic lower extremities and progressive motor weakness, with no sensory change. The MRI showed an acute extradural haematoma extending from C7 to T4 with compression of the spinal cord. After submission to decompression surgery, he presented full recovery in 1 month. The histopathological analysis revealed a vascular malformation.info:eu-repo/semantics/publishedVersio

Pt-Decorated TiO2 Materials Supported on Carbon : Increasing Activities and Stabilities toward the ORR by Tuning the Pt Loading

Pt nanoparticles (Pt NPs) supported on carbon have been widely employed as electrocatalysts toward oxygen reduction reaction. The development of more efficient electrocatalysts that enable one to reduce or even not require the use of Pt is a central challenge. In addition to the control over the physical and chemical features of Pt NPs, metal support interactions can be employed to enhance activities via the generation and exposure of surface-active sites. In this context, we report herein the development of electrocatalysts composed of Pt NPs supported on TiO2 microspheres, that were subsequently impregnated onto carbon. We have found that, by optimizing the loading of Pt at the TiO2 surface, the electrocatalytic activity toward the ORR could be improved compared to that of the commercial Pt/C (E-TEK) material, even at lower Pt loadings. The enhancement in activities could be assigned to the balance between Pt loading and generation of reactive surface sites, such as adsorbed oxygenated species. Moreover, the utilization of TiO2 as support enabled improved stabilities relative to Pt/C (E-TEK). We believe that the results described herein may inspire the development of electrocatalysts for the ORR with improved activities and stabilities.Peer reviewe

Three-Dimensional Numerical Simulations of Equatorial Spread F: Results and Observations in the Pacific Sector

A three-dimensional numerical simulation of plasma density irregularities in the postsunset equatorial F region ionosphere leading to equatorial spread F (ESF) is described. The simulation evolves under realistic background conditions including bottomside plasma shear flow and vertical current. It also incorporates C/NOFS satellite data which partially specify the forcing. A combination of generalized Rayleigh-Taylor instability (GRT) and collisional shear instability (CSI) produces growing waveforms with key features that agree with C/NOFS satellite and ALTAIR radar observations in the Pacific sector, including features such as gross morphology and rates of development. The transient response of CSI is consistent with the observation of bottomside waves with wavelengths close to 30 km, whereas the steady state behavior of the combined instability can account for the 100+ km wavelength waves that predominate in the F region