Electron-induced ionization and cationic fragmentations of the isolated molecule of 2,4-imidazolidinedione (hydantoin): a study of the relaxing path thresholds.

In this work, our new experimental setup has been used to study the ionization and fragmentation of a prebiotic molecule, hydantoin, by electron impact. Scanning of the incident electron energy allows the determination of the appearance thresholds of the cations. The vertical ionization potential was found to be in good agreement with previous data. Dissociation thresholds for the main fragmentation patterns were also measured. In parallel, thanks to quantum chemical calculations, reaction schemes compatible with the experimental results are given.

Differential diagnosis of carpal and tarsal ankylosis on dry bones: Example from the catacomb of Saints Peter and Marcellinus (Rome, 1st-3rd century AD).

Bone ankylosis is a pathological feature that may occur in many chronic diseases involving joints. In paleopathology, it is therefore challenging to attribute such a change to a specific condition. Here, we illustrate the differential diagnosis by discussing the lesions observed on an incomplete skeleton from the Roman period, recovered from the catacomb of Saints Peter and Marcellinus (Rome, Italy). The skeleton exhibits several bone changes, including ankylosis on both feet and the left hand. The right tarsal fusion is accompanied by soft tissue ossifications involving the plantar aponeurosis and the tendinous structures connecting the great toe's proximal phalanx and sesamoid bones. The lesions recorded suggest that a spondyloarthropathy is the most likely cause of these extensive fusions.