Progress in nanotechnology calls for material probing techniques of high sensitivity and resolution. Such techniques are also used for high-impact studies of nanoscale materials in medicine and biology. Soft X-ray microscopy has been successfully used for investigating complex biological processes occurring at micrometric and sub-micrometric length scales and is one of the most powerful tools in medicine and the life sciences. Here, we present the capabilities of the TwinMic soft X-ray microscopy end-station at the Elettra synchrotron in the context of medical and biological imaging, while we also describe novel uses and developments.

Male infertility is a worldwide clinical issue that increases the number of couples resorting to assisted reproductive technologies (ARTs) to achieve pregnancy. Photobiomodulation therapy (PBMT) is a promising technique that can biostimulate cells and tissues and it is currently successfully employed to enhance the sperm motility in vitro. Nevertheless, its use has been so far restricted to the research field. In the present work, we exploited two PBMT protocols at an 800 nm wavelength on sperm derived from infertile individuals, detecting an increase in sperm motility 1 hour after irradiation. Moreover, in order to add new information about the molecular effect of PBMT, the content of some light elements was evaluated using high resolution X-ray fluorescence imaging. Interestingly, an increase in Na content was detected in the irradiated samples, possibly suggesting a role of this element in sperm motility; indeed, a low Na content was previously correlated with a poor sperm quality, low semen volume, and modest fertilization rate. Amplifying the knowledge of PBMT in the ART field will expedite the translational potentiality of the PBMT use in clinical settings.

In hard X-ray applications that require high detection efficiency and short response times, such as synchrotron radiation-based Mössbauer absorption spectroscopy and time-resolved fluorescence or photon beam position monitoring, III–V-compound semiconductors, and dedicated alloys offer some advantages over the Si-based technologies traditionally used in solid-state photodetectors. Amongst them, gallium arsenide (GaAs) is one of the most valuable materials thanks to its unique characteristics. At the same time, implementing charge-multiplication mechanisms within the sensor may become of critical importance in cases where the photogenerated signal needs an intrinsic amplification before being acquired by the front-end electronics, such as in the case of a very weak photon flux or when single-photon detection is required. Some GaAs-based avalanche photodiodes (APDs) were grown by a molecular beam epitaxy to fulfill these needs; by means of band gap engineering, we realised devices with separate absorption and multiplication region(s) (SAM), the latter featuring a so-called staircase structure to reduce the multiplication noise. This work reports on the experimental characterisations of gain, noise, and charge collection efficiencies of three series of GaAs APDs featuring different thicknesses of the absorption regions. These devices have been developed to investigate the role of such thicknesses and the presence of traps or defects at the metal–semiconductor interfaces responsible for charge loss, in order to lay the groundwork for the future development of very thick GaAs devices (thicker than 100 $\mathsf{\mu }$m) for hard X-rays. Several measurements were carried out on such devices with both lasers and synchrotron light sources, inducing photon absorption with X-ray microbeams at variable and controlled depths. In this way, we verified both the role of the thickness of the absorption region in the collection efficiency and the possibility of using the APDs without reaching the punch-through voltage, thus preventing the noise induced by charge multiplication in the absorption region. These devices, with thicknesses suitable for soft X-ray detection, have also shown good characteristics in terms of internal amplification and reduction of multiplication noise, in line with numerical simulations.

The production of devotional reliefs, flourished in 15th century in Florence, where models from Renaissance Masters were reproduced in series by using a large variety of materials. One of the most frequently used is gypsum plaster, often referred to as “stucco” or “gesso”. Despite devotional reliefs wide diffusion, details concerning their constitutive materials and manufacture are insufficiently studied. In the framework of a research program fostered by the Louvre Museum, a multi-analytical approach was devised to investigate the composition and structure of micro samples obtained from a total of twenty-six representative artworks attributed to seven Florentine Masters. New evidence related to i) accessory minerals, ii) minor and trace elements, and iii) pores microstructure, disclosed important insights into the production of 15th century Florentine botteghe. These evidences, corroborated by the activity of some artists across Italy, raise new hypotheses on the attribution of some of these Madonne di gesso and their production outside Florence.

As part of an ongoing project dealing with the technical study of 15th century Florentine devotional reliefs, a focus was made to investigate their production by serial casting. Manufacturing techniques of the so-called Madonne di gesso were investigated on 12 artworks chosen after three different models of Donatello and B. Bellano, Desiderio da Settignano and Antonio Rossellino. Results obtained with a structured light 3D scanner were invaluable for art historians. Despite their location, a simultaneous examination of the reliefs kept in the Louvre Museum and in Florence (Bargello and Bardini Museums) was carried out, as well as a mesh comparison of their 3D models. This allowed us to identify and measure millimetric differences of shapes and topography between reliefs of the same type and/or casting series. Indeed, direct correlations have been established by verifying the low-reliefs most likely produced from the same mould/prototype. In some cases, a chronology within the casting series has been proposed. Results disclosed manufacturing insights on these artworks produced in 15th century Florentine botteghe.