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Biomedical subjects

L De Nardo

Publications and source records attributed to L De Nardo.

28 records · Page 2Linked to original sources

A feasibility study of a single event spectrometer based on semiconductor devices.

The electronics employed around particle accelerators can be disturbed or damaged because of single event effects (SEE). The most likely effect is the single event upset (SEU) which may affect all memory devices. In the case of high energy accelerators, SEUs are mostly produced by secondary charged particles generated by neutron interactions. The measurement of the energy and the lineal energy distribution of these neutron-induced charged particles was proposed. As a first approach, a commercial p-i-n photodiode was employed. This device was irradiated with thermal and monoenergetic fast neutrons. Some effects limiting the use of such a detector as a SEE spectrometer were observed, giving guidelines for the design of an application specific integrated circuit (ASIC). The possibility of creating a solid state microdosemeter by coupling the ASIC with a tissue-equivalent radiator is discussed. Moreover, the p-i-n photodiode covered with a hydrogenated plastic radiator may be employed as a proton-recoil spectrometer.

Dose-Response Relationship, Radiation↗

Track nanodosimetry of an alpha particle.

Experimental measurements and calculations are described of ionisation distributions in propane wall-less gas cavities of about 20 nm simulated size, performed at different distances from a 244Cm alpha particle track. Ionisation events are detected one by one by collecting electrons from the sensitive volume and by separating them with a drift column. Experimental results and Monte Carlo calculations indicate that, in the delta ray cloud, conditional probability curves, average cluster size and the ratio of second moment above first moment of the cluster distribution are invariant with track distance.

Alpha Particles↗

[A case of primary cardiac tumor in childhood. Echographic and anatomo-pathologic study].

Primary cardiac tumors are rare in children. The benign forms constitute 90% of cases, with often fatal clinical course due to the origin site. Here is reported a case of fibroelastic hamartoma in a four month baby, with multiple malformations, in which the initial signs have been alterations of ECG and of the cardiac profile at Rx chest. Bidimensional echocardiography suggested the correct diagnosis, revealing the mass in the interventricular septum. Cardiac catheterization excluded connections with coronary arteries. The baby died before cardiosurgical operation, probably because of a hyperkinetic ventricular arrhythmia. Anatomo-pathologic examination discusses the diagnosis of this tumor versus other kinds, defining our case as a fibroelastic hamartoma.

Female↗

[Hypoparathyroidism and Addison's disease with moniliasis: report of two cases in childhood (author's transl)].

Two pediatric cases are described presenting a conjunction of Addison's disease and hypoparathyroidism. One of the two cases also exhibits moniliasis of the oral cavity (Whitaker's disease). A full report is given of the symptoms and of the laboratory analyses which have motivated the diagnosis, and of the endocrinological function tests which were intended to confirm the diagnosis. The clinical process and the therapeutic criteria adopted are subsequently reported. A discussion follows focusing on the possible causes of the coexistence of the immunological defect and of the endocrinous deficiencies which are typical of the syndrome. Pathogenetic priority is attributed to the immunological defect which induces a autoimmune lesion of the endocrinous glands concerned.

Addison Disease↗