During water electrolysis, adding an electrocatalyst for the hydrogen evolution reaction (HER) is necessary to reduce the activation barrier and thus enhance the reaction rate. Metal chalcogenide-based 2D nanomaterials have been studied as an alternative to noble metal electrocatalysts because of their interesting electrocatalytic properties and low costs of production. However, the difficulty in improving the catalytic efficiency and industrializing the synthetic methods have become a problem in the potential application of these species in electrocatalysis. Liquid-phase exfoliation (LPE) is a low-cost and scalable technique for lab- and industrial-scale synthesis of 2D-material colloidal inks. In this work, we present, to the best of our knowledge, for the first time a systematic study on the surfactant-assisted LPE of bulk Bi2S3 crystalline powder to produce nanosheets (NSs). Different dispersing agents and LPE conditions have been tested in order to obtain colloidal low-dimensional Bi2S3 NSs in H2O at optimized concentrations. Eventually, colloidally stable layered nano-sized Bi2S3 suspensions can be produced with yields of up to ~12.5%. The thus obtained low-dimensional Bi2S3 is proven to be more active for HER than the bulk starting material, showing an overpotential of only 235 mV and an optimized Tafel slope of 125 mV/dec. Our results provide a facile top-down method to produce nano-sized Bi2S3 through a green approach and demonstrate that this material can have a good potential as electrocatalyst for HER.

Metal-on-metal total hip arthroplasty prostheses are known to release cobalt and chrome (CoCr) debris. The local accumulation of these ions and nanoparticles can cause adverse local tissue reaction, which can ultimately determine a negative outcome for patients. The aim of our systematic review was to report the latest evidence on the effects of CoCr particles on local soft tissue with a focus on its clinical relevance. PubMed, Embase, and Cochrane Library databases were screened to perform an extensive review. PRISMA guidelines were applied, and the risk of bias was assessed, as was the methodological quality of the included studies. 27 studies were included after applying the inclusion and exclusion criteria. 3 were human ex vivo studies, 24 were preclinical studies, including 21 in vitro and 3 in animal models. The presence of metal ions results in cell damage by reducing cell viability, inducing DNA damage, and triggering the secretion of cytokines, which are responsible for the inflammatory reaction observed in ALTR. CoCr particles released from MoM implants can cause damage to skeletal muscle, the capsule, and provoke osteolysis and inflammation. The cytotoxic and genotoxic damages, as well as the interaction with the immune system, affect the success of the arthroplasty and lead to a higher rate of revision surgeries. Statement of clinical significance: Ions released from the wear of Metal-on-Metal implant are significantly associated with soft tissue damage, and other local adverse reaction. Multiple mechanistic reasons are proposed.

Air pollution, besides being one of the leading causes of death worldwide, remains one of the most controversial topics in environmental monitoring. The current state of the art refers to remote satellite analysis and static ground-level technologies. The O-ZONE project has set itself the objective of bridging this technological gap using dynamic in situ analysis using compact, inexpensive and reusable samplers that can be integrated onboard stratospheric balloons and drones. The prototype, therefore, consists of a pneumatic system, a set of filters and a sampling bag. Thanks to this architecture, it is possible to sample atmospheric air at different altitudes. After the flight, the samples collected are analysed using chromatographic techniques to provide a picture of the various air layers. On 30 September 2021, the fully autonomous payload successfully flew in Kiruna (Swedish Lapland) aboard BEXUS 30, the stratospheric balloon made available by the promoters of the “hands-on” project of the same name, SNSA (Swedish National Space Agency), DLR (Deutsches Zentrum für Luft- und Raumfahrt) and ESA (European Space Agency). In this paper, the technical specifications of the device are described, with a focus on the sampling system; we then highlight the results obtained by the filters that, at different altitudes, collected stratospheric pollutants such as VOCs and, in the first layers of the atmosphere, PM. In conclusion, an interpretation of the results is provided to better understand the possible future uses of the prototype.

The current situation regarding air pollution, global warming and the world approaching the point of no return have led the United Nations to focus on improving the environmental situation through the SDGs [1]. In line with these ambitions, O-ZONE team, was born in 2019 with the clear objective of taking concrete action against climate change [2]. The team's goal is to build a compact, low-cost, and reusable device to sample stratospheric pollutants, at various altitudes and thus provide air quality indications in mid-range areas for monitoring, prevention, and rapid intervention in case of unpredictable events. The O-ZONE team was therefore born as an idea of some students from the Aerospace Engineering course at the same University. The students took part in the REXUS/BEXUS project by Swedish National Space Agency (SNSA), Deutsches Zentrum für Luft- und Raumfahrt (DLR) and European Space Agency (ESA) [3]. As in each of these projects, the team tackled the various steps of space missions but, in this case, with extra constraints. They had to work during the lockdown with various complications due to the pandemic. Although the launch was delayed, the students carried on with their motivation and then launched their device on board the BEXUS 30. The prototype launched in Kiruna - Sweden (at the Esrange base), and which reached an altitude of 27.8 km, is a sampling system for Volatile Organic Compounds (VOCs), such as NOX and SOX, Particulate Matter (PM) and Chlorofluorocarbons (CFCs) responsible for the depletion of the Ozone layer [4]. These types of samplers [2] fill the technological gap in atmospheric analysis; the current state of the art allows air to be monitored only statically from ground stations or by satellite analysis [5], while O-ZONE presents an accessible, easy-to-use and rapid in situ sampling method. This paper describes the technical specifications and design aspects of the device and the experience that has allowed the students to grow as a team, especially in terms of personal skills and the ability to work with concurrent engineering and interdisciplinarity. Finally, the experiment results will be shown.