Design and Test of a Calibration System for Avalanche Photodiodes Used in X-Ray Compton Polarimeters for Space.

The development and calibration of a measurement system designed for assessing the performance of the avalanche photodiodes (APDs) used in the Compton scattering polarimeter of the CUSP project is discussed in this work. The designed system is able to characterize the APD gain GAPD and energy resolution across a wide range of temperatures (from -20 °C to +60 °C) and bias voltages Vbias (from 260 V to 410 V). The primary goal was to experimentally determine the GAPD dependence on the and Vbias in order to establish a strategy for stabilizing GAPD by compensating for fluctuations, acting on Vbias.

Age-related analysis of glucose metabolism in spontaneously hypertensive and normotensive rats.

This study was designed to investigate the effect of both hypertension and ageing on the efficiency of glucose metabolism. A 12-sample, 120 min intravenous glucose tolerance test (IVGTT) was applied to 36 rats: two groups of nine young (12 weeks) spontaneously hypertensive and Wistar Kyoto rats (Y-SHR and Y-WKY group, respectively) and two groups of nine old (40 weeks) SHR and WKY rats (O-SHR and O-WKY group, respectively). Insulinaemia and glycaemia data were interpreted in terms of estimates of glucose effectiveness, S(G), and insulin sensitivity, S(I), provided by the minimal model of glucose kinetics.

Interaction between glucose metabolism and endogenous insulin release in hypertension.

The minimal model approach was applied to examine the dynamic interaction between glucose metabolism and endogenous insulin release during an intravenous glucose tolerance test (IVGTT) in a group of hypertensive patients (H group) compared with a group of normotensive subjects (N group). A modified version of the classical minimal model of C-peptide kinetics and secretion was used to evaluate the total amount of insulin secretion per unit of distribution volume (TIS) together with 3 indexes of beta-cell function (the basal, Phi(b), first, Phi1, and second phase, Phi2, beta-cell sensitivity to glucose). These indexes were associated with estimates of glucose effectiveness (S(G)) and insulin sensitivity (S(I)) provided by the classical minimal model of glucose kinetics.