University of Palermo

About: University of Palermo is a education organization based out in Palermo, Italy. It is known for research contribution in the topics: Population & Medicine. The organization has 15621 authors who have published 40250 publications receiving 964384 citations. The organization is also known as: Università degli Studi di Palermo & Universita degli Studi di Palermo.

Inhibition of Thromboxane Biosynthesis and Platelet Function by Simvastatin in Type IIa Hypercholesterolemia

Abstract: Thromboxane A2 (TXA2) biosynthesis is enhanced in the majority of patients with type IIa hypercholesterolemia. Because simvastatin (a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor) was previously shown to reduce platelet aggregation and TXB2 production ex vivo, we investigated TXA2 biosynthesis and platelet function in 24 patients with type IIa hypercholesterolemia randomized to receive in a double-blind fashion simvastatin (20 mg/d) or placebo for 3 months. The urinary excretion of 11-dehydro-TXB2, largely a reflection of platelet TXA2 production in vivo, was measured by a previously validated radioimmunoassay technique. Blood lipid levels and urinary 11-dehydro-TXB2 excretion were significantly (P < .001) reduced by simvastatin. In contrast, placebo-treated patients did not show any statistically significant changes in either blood lipids or 11-dehydro-TXB2 excretion. The reduction in 11-dehydro-TXB2 associated with simvastatin was correlated with the reduction in total cholesterol (r = .81, P < .0001), LDL cholesterol (r = .79, P < .0001), and apolipoprotein B (r = .76, P < .0001) levels. Platelets from patients with type IIa hypercholesterolemia required significantly (P < .01) more collagen and ADP to aggregate and synthesized less TXB2 in response to both agonists after simvastatin therapy. Bleeding time, platelet sensitivity to Iloprost, and blood lipoprotein(a) and HDL cholesterol levels were not significantly affected by either treatment. We conclude that enhanced TXA2 biosynthesis in type IIa hypercholesterolemia is, at least in part, dependent on abnormal cholesterol levels and/or other simvastatin-sensitive mechanisms affecting platelet function.

Efficiency enhancement of permanent-magnet synchronous motor drives by online loss minimization approaches

Abstract: In this paper, a new loss minimization control algorithm for inverter-fed permanent-magnet synchronous motors (PMSMs), which allows for the reduction of the power losses of the electric drive without penalty on its dynamic performance, is analyzed, experimentally realized, and validated. In particular, after a brief recounting of two loss minimization control strategies, namely, the "search control" and the "loss-model control," both a new modified dynamic model of the PMSM (which takes into account the iron losses) and an innovative "loss-model" control strategy are presented. Experimental tests on a specific PMSM drive employing the proposed loss minimization algorithm have been performed, aiming to validate the actual implementation. The main results of these tests confirm that the dynamic performance of the drive is maintained, and in small motors enhancement up to 3.5% of the efficiency can be reached in comparison with the PMSM drive equipped with a more traditional control strategy.