Supercritical CO2 sterilization: An effective treatment to reprocess FFP3 face masks and to reduce waste during COVID-19 pandemic.

The outbreak of COVID-19 pandemic unveiled an unprecedented scarcity of personal protective equipment (PPE) available in sanitary premises and for the population worldwide. This situation fostered the development of new strategies to reuse PPE that would ensure sterility and, simultaneously, preserve the filtering properties of the materials. In addition, the reuse of PPEs by reprocessing could reduce the environmental impact of the massive single-use and disposal of these materials. Conventional sterilization techniques such as steam or dry heat, ethylene oxide, and gamma irradiation may alter the functional properties of the PPEs and/or leave toxic residues. Supercritical CO2 (scCO2)-based sterilization is herein proposed as a safe, sustainable, and rapid sterilization method for contaminated face masks while preserving their performance. The functional (bacterial filtration efficiency, breathability, splash resistance, straps elasticity) properties of the processed FFP3 face masks were evaluated after 1 and 10 cycles of sterilization. Log-6 sterilization reduction levels were obtained for face masks contaminated with Bacillus pumilus endospores at mild operating conditions (CO2 at 39 °C and 100 bar for 30 min) and with low contents of H2O2 (150 ppm). Physicochemical properties of the FFP3 face masks remained unchanged after reprocessing and differences in efficacy were not observed neither in the filtration tests, following UNE-EN 14683, nor in the integrity of FFP3 filtration after the sterilization process. The herein presented method based on scCO2 technology is the first reported protocol achieving the reprocessing of FFP3 masks up to 10 cycles while preserving their functional properties.

Female puma (Puma concolor) highway crossings in the Yucatan Peninsula

La infraestructura humana, particularmente las carreteras, ha demostrado ser un peligro para la capacidad de mantenimiento de las poblaciones de grandes felinos en el mundo. La península de Yucatán no es una excepción a esta situación;aunado al establecimiento del Tren Maya, un ferrocarril continental, que reformará la red de carreteras de la Península. Describimos 12 cruces exitosos de una carretera de cuatro carriles por un puma hembra equipado con un radio-transmisor de GPs. El tiempo entre ubicaciones secuenciales tuvo una mediana de 24 h (con un rango de 8 a 56 h). El número promedio de días entre cruces fue de 4.33 (SD = 2.50). Este comportamiento pudo ser influido por una reducción en la movilidad humana por la pandemia producida por COVID-19. Identificamos un tramo de 3 km de largo donde ocurrieron los cruces de carretera. Describimos las características de esta porción de carretera y recomendamos construir estructuras de paso de vida silvestre de acuerdo a ellas.Alternate abstract:Human infrastructure, particularly highway infrastructure, has proven to be a hazard for the resilience of large felid populations throughout the world. The Yucatan Peninsula is no exception and is presently confronted with the establishment of the "Tren Maya," a continental railway that will reshape the road network of the peninsula. We describe 12 successful crossings of a 4-lane highway on the peninsula by a female puma (Puma concolor) fitted with a GPS radio-transmitter. The median time between sequential locations was 24 h (range 8-56 h), and the average number of days between crossings was 4.33 (SD = 2.50). Felid behavior and movements in relation to roads may be influenced by reduced human mobility due to the COVID-19 pandemic lockdown. We identified a 3-km stretch of highway where the crossings occurred. We describe the characteristics of the area and recommend building wildlife passage structures appropriate for the site.