arXiv subjects
Publications and source records attributed to M. Ceccarelli.
TEX facility if commissioned for high power testing to characterize accelerating structures and validate them for the operation on future particle accelerators for medical, industrial and research applications. At this aim, TEX is directly involved in the LNF leading project EuPRAXIA@SPARC_Lab. The brief description of the facility and its status and prospective will be provided.
In all Countries the political decisions aim to achieve an almost stable configuration with a small number of new infected individuals per day due to Covid-19. When such a condition is reached, the containment effort is usually reduced in favor of a gradual reopening of the social life and of the various economical sectors. However, in this new phase, the infection spread restarts and a quantitative analysis of the regrowth is very useful. We discuss a macroscopic approach which, on the basis of the collected data in the first lockdown, after few days from the beginning of the new phase, outlines different scenarios of the Covid-19 diffusion for longer time. The purpose of this paper is a demonstration-of-concept: one takes simple growth models, considers the available data and shows how the future trend of the spread can be obtained. The method applies a time dependent carrying capacity, analogously to many macroscopic growth laws in biology, economics and population dynamics. The illustrative cases of Singapore, France, Spain and Italy are analyzed.
The $^{10}$B isotope has been almost exclusively used in the neutron-capture radiation therapy (NCT) of cancer for decades. We have identified two other nuclides suitable for the radiotherapy, which have ca.10 times larger cross section of absorption for neutrons and emit heavy charged particles. This would provide several key advantages for potential NCT, such as the possibility to use either a lower nuclide concentration in the target tissues, or a lower neutron irradiation flux. By detecting the characteristic $γ$ radiation from the spontaneous decay of the radionuclides, one can image and control their accumulation. These advantages could be critical for the revival of the NCT as a safer, more efficient and more widely used cancer therapy.
We present an implicit statistical model for the steric effect on the potential of mean force (PMF) of a molecule diffusing through a flexible nanochannel of varying size. The average cross sectional area profile of the channel and the average minimal projection area of the molecule are the two major quantities determining the steric part of the PMF barrier for the translocation of the particle in the case of a small rigid particle and a large rigid channel. In this case, the description is reduced to the Fick-Jacobs model and the PMF is completely entropic. However, the flexibility of channel's cross section and that of molecule's size play crucial role when a large molecule goes through a narrow channel. The PMF profile changes its statictical nature and becomes enthalpic. We treat the flexibility in terms of the equilibrium fluctuations of the pore and of the molecule, independently. For the case of gaussian fluctuations, we derived simple analytical expressions for the steric barrier.