High incidence of severe ischaemic complications in patients with giant cell arteritis irrespective of platelet count and size, and platelet inhibition

Objective. Vision loss and ischaemic stroke are feared complications in GCA. We investigated how platelet count and size and platelet inhibition with ASA relate to ischaemic complications in patients with GCA. Methods. Charts of patients with GCA were retrospectively analysed. Jaw claudication, amaurosis fugax, blurred vision, ischaemic stroke and permanent visual loss were classified as ‘ischaemic events'; ischaemic stroke and permanent visual loss were sub-grouped as ‘severe ischaemic events'. The incidence of ischaemia and the association to the pre-defined covariates age, fever, ESR, platelet count and size and ASA treatment were assessed. Results. Eighty-five patients (mean age 73 yrs, 60% women, 78% biopsy-proven) were included in the analysis. Of the 85 patients, 62 (73%) presented with ischaemic events, 29/85 patients (34%) with severe ischaemic events. At the time of diagnosis 22/85 patients (26%) were treated with ASA. Of these 22 patients, 15 (68%) presented with ischaemic events, 7/22 patients (32%) with severe ischaemic events. In multivariate analysis, neither platelet count nor size or ASA treatment were significantly associated with ischaemic or severe ischaemic events. Conclusions. The incidence of severe ischaemic events in patients with GCA was high, irrespective of platelet count and size and established ASA treatmen

X-ray absorption spectroscopy on layered cobaltates Na_xCoO_2

Measurements of polarization and temperature dependent soft x-ray absorption have been performed on Na_xCoO_2 single crystals with x=0.4 and x=0.6. They show a deviation of the local trigonal symmetry of the CoO_6 octahedra, which is temperature independent in a temperature range between 25 K and 372 K. This deviation was found to be different for Co^{3+} and Co^{4+} sites. With the help of a cluster calculation we are able to interpret the Co L_{23}-edge absorption spectrum and find a doping dependent energy splitting between the t_{2g} and the e_g levels (10Dq) in Na_xCoO_2.Comment: 7 pages, 8 figure

Durability testing at 5 atmospheres of advanced catalysts and catalyst supports for gas turbine engine combustors

The durability of CATCOM catalysts and catalyst supports was experimentally demonstrated in a combustion environment under simulated gas turbine engine combustor operating conditions. A test of 1000 hours duration was completed with one catalyst using no. 2 diesel fuel and operating at catalytically-supported thermal combustion conditions. The performance of the catalyst was determined by monitoring emissions throughout the test, and by examining the physical condition of the catalyst core at the conclusion of the test. Tests were performed periodically to determine changes in catalytic activity of the catalyst core. Detailed parametric studies were also run at the beginning and end of the durability test, using no. 2 fuel oil. Initial and final emissions for the 1000 hours test respectively were: unburned hydrocarbons (C3 vppm):0, 146, carbon monoxide (vppm):30, 2420; nitrogen oxides (vppm):5.7, 5.6

Combined 3D Scanning PIV and Scanning LIF for flow and phase transfer measurements around a melting particle

Interfacial flow and phase transfer around a melting solid particle were investigated with combined 3D Scanning PIV and Scanning LIF technique. Experiments were carried out with a spherical ice-particle, which was initially shock-frozen from water saturated with fluorescent dye. Flow in a water tank seeded with small tracer particles was investigated, when the ice-particle was released at the water surface in the center of the tank and the melting process began. A scanning light-sheet was generated with a polygonal mirror and flow was recorded with two high-speed cameras with a beam splitter plate. The cameras were equipped with different color filter such that cam#1 recorded only the clean water while cam#2 recorded the molten fluid generated by the heat transfer of the frozen fluorescent ice-particle. This allowed us to record the 3D flow and 3D concentration field simultaneous. The results showed the complexity of induced flow process by the heat/phase transfer and buoyancy interacting with the base flow in the water tank. A small swirl in the tank was enforced by buoyancy-induced vortex stretching and resulted in increasing particle rotation. This self-enforcing process generated a columnar vortex in the wake below the particle which underwent vortex breakdown. Fluid originating from the phase transfer process was accumulated in the vortex