Depolymerization of sodium polyphosphates on an iron oxide surface at high temperature.

Density functional theory (DFT) and first principles molecular dynamics (FPMD) studies of pyrophosphate cluster Na4P2O7 and triphosphate cluster Na5P3O10 absorbed and decomposed on an Fe2O3(0001) surface have been conducted. Comparative analyses of the structure properties and adsorption processes during the simulation at elevated temperature have been carried out. The results depict the key interactions including the covalent P-O bonds, pure ionic Na-O or Fe-O interactions. The iron oxide surface plays an important role in the bridging bond decomposition scheme which can both promote and suppress phosphate depolymerization. It is found that the chain length of polyphosphates does not have considerable effects on the decomposition of phosphate clusters. This study provides detailed insights into the interaction of a phosphate cluster on an iron oxide surface at high temperature, and in particular the depolymerization/polymerization of an inorganic phosphate glass lubricant, which has an important behavior under hot metal forming conditions.

[Very long term follow-up after radiofrequency ablation for atrial fibrillation: the Geneva experience]. / Suivi à tres long terme après ablation par radiofréquence de la fibrillation auriculaire: expérience à Genève.

Catheter ablation (CA) has emerged as an increasingly popular treatment option for selected patients with atrial fibrillation (AF) because drugs are frequently limited by side effects and poor effectiveness. However, very little data is available regarding outcomes of CA of AF beyond 5 years. Guidelines' recommendations are not clear regarding long-term oral anticoagulation (OAC) after 2 years. We assessed thromboembolic events (TE) and AF ablation outcomes at very long-term follow-up (> 5 years) after CA. During a mean follow-up of 9 years after CA, 68% patients were in stable sinus rhythm without anti-arrhythmic drugs and the TE event rate was 0.41 per 100 patients/year. Our data suggests that patients post ablation with a high risk for stroke (CHA2DS2-VASc ≥ 2) should however continue OAC treatment.

Dielectric properties of beef, beef liver, chicken and salmon at frequencies from 100 to 2500 MHz.

The dielectric properties of uncooked beef, beef liver, chicken and salmon meat were measured at frequencies between 100 and 2500 MHz and at selected temperatures between 1.2 degrees C and 65 degrees C. Experimental method and the sample holder are briefly described. The results for the dielectric constant and the dielectric loss factor are presented as a function of frequency at selected temperatures and show a trend consistent with theoretical expectation.