Rafi, J. M.
Pellegrini, G.
Godignon, P.
Quirion, D.
Hidalgo, S.
Matilla, O.
Fontsere, A.
Molas, B.
Takakura, K.
Tsunoda, I.
Yoneoka, M.
Pothin, D.
Fajardo, P.
Silicon photodiodes are very useful devices as X-ray beam monitors in synchrotron radiation beamlines, as well as other astronomy and space applications. Owing to their lower susceptibility to variable temperature and illumination conditions, there is also special interest in silicon carbide devices for some of these applications. Moreover, radiation hardness of the involved technologies is a major concern for high-energy physics and space applications. This work presents four-quadrant photodiodes produced on ultrathin (10 mu m) and bulk Si, as well as on SiC epilayer substrates. An extensive electrical characterization has been carried out by using current-voltage (I-V) and capacitance-voltage (C-V) techniques. The impact of different temperature (from -50 degrees C to 175 degrees C) and visible light conditions on the electrical characteristics of the devices has been evaluated. Radiation effects caused by 2 MeV electron irradiation up to 1 x 10(14), 1 x 10(15) and 1 x 10(16) e/cm(2) fluences have been studied. Special attention has been devoted to the study of charge build-up in diode interquadrant isolation, as well as its impact on interquadrant resistance. The study of these electrical properties and its radiation-induced degradation should be taken into account for device applications.
Rafi, J. M.
Boulord, C.
Hayama, K.
Ohyama, H.
Campabadal, F.
Pellegrini, G.
Lozana, M.
Simoen, E.
Claeys, C.
Particle-tracking detectors made on high-resistivity (HR) float zone (FZ) silicon are widely used in high-energy physics experiments. It is known that the incorporation of oxygen in the FZ Si can lead to some improvement in the radiation hardness of the material. In this contribution we investigate the effects of 2 MeV electron irradiation, up to a fluence of 5 x 10(16) e/cm(2), on the electrical and carrier lifetime properties of p-on-n silicon diodes fabricated on different substrate materials, including FIR standard and oxygenated FZ, as well as FIR magnetic Czochralski silicon, with a higher intrinsic oxygen contents. A progressive degradation of the characteristics is observed for all devices, pointing to a generation of bulk damage. Interestingly, a significant increase of the effective carrier concentration is observed after the highest fluences for all materials. Under the limited experimental conditions studied, no significant changes are observed for diode characteristics subjected to a thermal annealing treatment at 80 degrees C. This degradation in the electrical properties should be taken into account for the use of such FIR Si materials under high-energy electron environments. (C) 2009 Elsevier B.V. All rights reserved.
Pandolfi, A.
Giaccari, A.
Polishuck, R.
Alberta, M. M.
Pellegrini, G.
Morviducci, L.
Vitacolonna, E.
Buongiorno, A. M.
Capani, F.
Consoli, A.
In diabetes, plasma fibrinolytic activity is decreased while plasma plasminogen activator inhibitor-1 (PAI-1) is increased. Both liver and adipose tissue can synthesize and release PAI-1, but PAI-1 synthesis in these tissues has not been investigated in diabetes. Furthermore, little is known about PAI-1 localization in arterial wall cell of diabetic animals. The aim of this study was to determine the effect of chronic hyperglycemia on plasma fibrinolysis and plasma PAI-1 levels and on liver, adipose tissue and arterial wall PAI-1 content in the rat. We compared plasma fibrinolytic activity (lysis of fibrin plates) and plasma PAI-1 activity (chromogenic assay) in 10 Sprague Dowley 90% pancreatectomized rats (a model of diabetes characterized by normal fasting insulin and the absence of obesity, therefore closely resembling lean type 2 diabetes) and in 15 sham-operated rats. Furthermore, we measured PAI-1-related fluorescence, by immunofluorescent staining and Laser Scanning Confocal Microscopy, in liver, adipose tissue and aortic wall in diabetic and control animals. In the diabetic animals plasma fibrinolytic activity was reduced (lysis areas = 163 +- 23 vs 308 +- 21 mm2, P < 0.001), while plasma PAI-1 activity was increased (4.61 +- 2.01 AU vs 0.70 +- 0.59 AU, P < 0.02). PAI-1 related fluorescence was increased in the liver (754 +- 25 vs 299 +- 14 AFU, P < 0.0001), in the adipose tissue (721 +- 32 vs 248 +- 14 AFU, P < 0.001) and in the aorta wall (339 +- 18 vs 274 +- 9 AFU, P < 0.005) of the diabetic animals. These data provide evidence that in diabetes mellitus hyperglycemia is associated with increased PAI-1 content in the liver, adipose tissue and in the arterial wall. This suggests that in diabetes the liver and adipose tissue can be important sources for increased plasma PAI-1 and local fibrinolysis can be affected by increased PAI-1 levels in the arterial wall.
Esposito, S.
Baggi, E.
Villani, A.
Norbedo, S.
Pellegrini, G.
Bozzola, E.
Palumbo, E.
Bosis, S.
Nigro, G.
Garazzino, S.
Principi, N.
The purpose of this investigation was to determine how specialists in paediatric infectious diseases (PIDs) manage children with suspected Lyme disease (LD) by comparing their approaches in Italian endemic and non-endemic areas. A cross-sectional survey of the PID specialists participating in the Italian Society for Pediatric Infectious Disease (SITIP) Registry of LD was carried out between 1 January and 30 April 2012. A total of 160 children (80 living in endemic areas and 80 living in non-endemic areas) were diagnosed as having LD between 1 January 2005 and 31 December 2011. The clinical manifestations were erythema migrans in 130 cases (81.3 %), arthritis in 24 (15.0 %) and neuroborreliosis in six (3.8 %). Significant differences from the recommendations concerning serology and the tests to undertake were mainly observed in the children with erythema migrans, especially those living in non-endemic areas (p < 0.05). The children with erythema migrans who lived in non-endemic areas were treated with antibiotics significantly less frequently than those living in endemic areas (p < 0.05), and significantly fewer children with erythema migrans or arthritis living in non-endemic areas were treated with amoxicillin in comparison with those living in endemic regions (p < 0.05). The duration of antimicrobial therapy was significantly shorter than recommended in the children with erythema migrans or arthritis, especially those living in non-endemic areas (p < 0.05). Paediatric LD is also present in areas of Italy in which it is not considered endemic, but knowledge concerning its management is generally poor among PID specialists and characterised by enormous gaps in non-endemic areas.