Effective SARS-CoV-2 antiviral activity of hyperbranched polylysine nanopolymers

The coronavirus pandemic (COVID-19) had spread rapidly since December 2019, when it was first identified in Wuhan, China. As of April 2021, more than 130 million cases have been confirmed, with more than 3 million deaths, making it one of the deadliest pandemics in history. Different approaches must be put in place to confront a new pandemic: community-based behaviours (i.e., isolation and social distancing), antiviral treatments, and vaccines. Although behaviour-based actions have produced significant benefits and several efficacious vaccines are now available, there is still an urgent need for treatment options. Remdesivir represents the first antiviral drug approved by the Food and Drug Administration for COVID-19 but has several limitations in terms of safety and treatment benefits. There is still a strong request for other effective, safe, and broad-spectrum antiviral systems in light of future emergent coronaviruses. Here, we describe a polymeric nanomaterial derived from l-lysine, with an antiviral activity against SARS-CoV-2 associated with a good safety profile in vitro. Nanoparticles of hyperbranched polylysine, synthesized by l-lysine's thermal polymerization catalyzed by boric acid, effectively inhibit the SARS-CoV-2 replication. The virucidal activity is associated with the charge and dimension of the nanomaterial, favouring the electrostatic interaction with the viral surface being only slightly larger than the virions' dimensions. Low-cost production and easiness of synthesis strongly support the further development of such innovative nanomaterials as a tool for potential treatments of COVID-19 and, in general, as broad-spectrum antivirals. This journal i

Physical and mental fatigue reduce psychomotor vigilance in professional football players

PURPOSE: Professional football players experience both physical and mental fatigue. The main aims of this randomized crossover study were to investigate the effect of mental fatigue on repeated sprint ability (RSA), and the effects of both physical and mental fatigue on psychomotor vigilance.METHODS: Seventeen male professional football players performed maximal 20-m shuttle sprints interspaced by incomplete recovery (RSA test). Running speed, heart rate (HR), brain oxygenation and rating of perceived exertion (RPE) were monitored during each sprint. The RSA test was preceded by either a 30-min Stroop task to induce mental fatigue (MF), or by watching a documentary for 30 min (CON) in a randomized counterbalanced order. Participants performed a psychomotor vigilance test (PVT) at baseline, after the cognitive task (MF or CON), and after the RSA test.RESULTS: HR and RPE significantly increased, while running speed and brain oxygenation significantly decreased over the repeated sprints (p < 0.001) with no significant differences between conditions. Response speed during the PVT significantly declined after the Stroop task but not after CON (p = 0.001). Response speed during the PVT declined after the RSA test in both conditions (p < 0.001) and remained lower in the MF condition compared to CON (p = 0.012).CONCLUSIONS: Mental fatigue does not reduce RSA. However, the results of this study suggest that physical and mental fatigue have negative and cumulative effects on psychomotor vigilance. Therefore, strategies to reduce both physical and mental fatigue should be implemented in professional football players