Ion acceleration by radiation pressure in thin and thick targets

Abstract Radiation Pressure Acceleration (RPA) by circularly polarized laser pulses is emerging as a promising way to obtain efficient acceleration of ions. We briefly review theoretical work on the topic, aiming at characterizing suitable experimental scenarios. We discuss the two reference cases of RPA, namely the thick target ("Hole Boring") and the (ultra)thin target ("Light Sail") regimes. The different scaling laws of the two regimes, the related experimental challenges and their suitability for foreseen applications are discussed

Wind-Tunnel Tests of a Tilt-Rotor Aircraft

A wide aerodynamic test campaign has been carried out on the tiltrotor aircraft ERICA at the Large Wind Tunnel of Politecnico di Milano by means of a modular 1:8 scale model in order to produce a dataset necessary to better understand the aerodynamic behaviour of the aircraft and to state its definitive design. The target of the tests was the measurement of the aerodynamic forces and moments in several different configurations and different attitudes. The test program included some conditions at very high incidence and sideslip angles that typically belong to the helicoptermode flight envelope and measurements of forces on the tail and on the tilting wings. A large amount of data has been collected that will be very useful to refine the aircraft design. In general the aircraft aerodynamics do not present any critical problems, but further optimisation is still possible. From the viewpoint of drag in the cruise configuration, the sponsons of the landing gear seem to be worth some further design refinement since they are responsible for a 20% drag increase with respect to the pure fuselage configuration. On the contrary, the wing fairing has proved to work well when the aircraft longitudinal axis is aligned with the wind, providing just a slight drag increase. Two other interesting aspects are the quite nonlinear behaviour of the side force for the intermediate sideslip angles as well as the noticeable hysteresis in the moment coefficient at very high incidence angles

Anatomical-radiological study of the plantar fascia and its correlation with Achilles tendon pathologies

Although the plantar fascia (PF) has been studied quite well from a biomechanical viewpoint [1], nothing is known about its content of elastic fibers, the features of the extracellular matrix or the extent of innervation. From a functional and clinical standpoint, the PF is often correlated with the triceps surae muscle, but the anatomical grounds for this link are not clear. Twelve feet from frozen human cadavers were dissected to isolate the PF. Specimens from each PF were tested with various histological and immunohistochemical stains. 52 MRI obtained in patients complaining of non-specific ankle or foot pain were analyzed. The thickness of PF and paratenon was assessed and statistical analyses were conducted. The PF is a tissue firmly joined to plantar muscles and is closely connected to the paratenon of Achilles tendon through the periosteum of the heel. The PF was rich in hyaluronan, probably produced by fibroblastic-like cells described as “fasciacytes” [2]. Nerve endings and Pacini and Ruffini corpuscles were present, particularly in the medial and lateral portions, and on the surface of the muscles, suggesting a role for the PF in the proprioception of foot. In the radiological study, 27 of the 52 MRI showed signs of Achilles tendon inflammation and/or degeneration, and the PF was 3.43 ± 0.48 mm thick, as opposed to 2.09 ± 0.24 mm in the cases in which the MRI revealed no Achilles tendon diseases (p<0.001). In the group of 27/52 cases with tendinopathies, the PF was more than 4.5 mm thick in 5, i.e. they exceeded the threshold for a diagnosis of plantar fasciitis. None of the other 25/52 cases had a PF more than 4 mm thick. There was a statistically significant correlation between the thicknesses of the PF and the paratenon. These findings suggests that the plantar fascia has a role not only in supporting the longitudinal arch of the foot, but also in its proprioception and peripheral motor coordination. Its relationship with the paratenon of the Achilles tendon is consistent with the idea of triceps surae structures being involved in the PF pathology, so their rehabilitation can be considered appropriate. Finally, the high concentration of hyaluronan in the PF points to the feasibility of using hyaluronan injections in the fascia to treat plantar fasciitis

Friar Leopoldo Mandic (1866–1942): the computed tomography of the body of a Saint

Post-mortem Computed tomography (CT) is an imaging technique for documentation and analysis of consecutive autopsy findings, including fractures and gross tissue injuries. Various post-processing techniques can provide strong forensic evidence for use in legal proceedings. On the other hand, this technique is implied also in paleopathology, in particular in mummy studies, with the aim of providing a permanent record of the mummy’s features, investigating the embalming procedure employed and analyzing the extent of the preservation in detail. For the Extraordinary Jubilee of Mercy, the mortal remains of Saint Leopoldo Mandic and Saint Pio da Pietrelcina, as examples of Mercy known by everyone, have been brought to Rome from 3 to 11 February. During the survey that preceded the preparation for transport to Rome, a whole-body CT was performed on the mummified corpse of Leopoldo Mandic, Capuchin Saint of Padova, Italy. The CT examination demonstrated the presence of arthritis at the level of the vertebral column, of the left knee and of the hand. Moreover, CT showed the preservation of skeleton, and partial preservation of the brain, ear ossicles, major arterial vessels (aorta and carotid arteries), pleurae, esophagus, heart, urinary bladder, nervous structures (plexuses and spinal nerves). Pseudo-pathologic changes, primarily postmortem skeletal dislocations were also present at the level of the hip joints. It is to emphasize the fact that San Leopoldo was not subjected before the CT to any conservative treatment, with the exception of a surface treatment with celluloid. CT demonstrated to be a non-destructive method to investigate Saint Leopoldo, in order to maintain the integrity of the body and to acquire data on his pathologies and on his preservation. CT allows not only the acquisition of sectional images but also, thanks to dedicated software, the post-processing and reconstruction of three-dimensional models, that can be used also for public displays