COVID-19: did the masks work?

During the early stages of the COVID-19 pandemic, we called for mandatory public masking to 'flatten the curve'. We helped formulate a national standard (SWiFT 19) for barrier facemasks, and, using a novel laser-based approach, we determined that mask efficacy is dependent on both fabric and fit; with both variables being inversely related. Herein, we take a retrospective view of the role of masks during the pandemic and surmise that, on the balance of evidence to date, masks were effective at stemming the spread of SARS-CoV-2 and may well be an effective early control strategy for potential future respiratory pandemics.

Face coverings, which cover the nose and mouth, are a means of preventing infections that travel in the air. These include viruses such as SARS-CoV-2, which causes COVID-19. Face coverings, or masks, played a key role during the COVID-19 pandemic by reducing person-to-person spread of the virus. The key features of a mask that make it effective are the material from which it is made and how closely the mask fits the face. A loosely fitting mask, for example, will lead to gaps around the nose and cheeks through which droplets can escape. A better fitting mask will have less leakage. Masks made from light single-layer material is less able to prevent droplet penetration than thicker, multi-layered fabric. Properly fashioned and fitted face masks are an effective means of slowing the spread of infections that travel in the air.

Effects of risk factors on evoked pain patterns in rat models of experimental knee osteoarthritis.

Pain experiences in patients with knee osteoarthritis (OA) may be influenced differently by OA risk factors, reducing the translatability of preclinical research into the clinic. Our objective was to contrast evoked pain patterns after exposure to different OA risk factors including acute joint trauma, chronic instability, or obesity/metabolic syndrome using rat models of experimental knee OA. We tested longitudinal patterns of evoked pain behaviors (knee pressure pain threshold and hindpaw withdrawal threshold) in young male rats exposed to different OA-inducing risk factors including (1) nonsurgical joint trauma (impact-induced anterior cruciate ligament (ACL) rupture); (2) surgical joint destabilization (ACL + medial meniscotibial ligament transection); and (3) high fat/sucrose (HFS) diet-induced obesity. Histopathology for synovitis, cartilage damage, and subchondral bone morphology was performed. Pressure pain threshold was reduced (more pain) most, and earlier by joint trauma (Week 4-12) and HFS (Week 8-28) than by joint destabilization (Week 12). Hindpaw withdrawal threshold was reduced transiently after joint trauma (Week 4), with smaller and later reductions after joint destabilization (Week 12), but not with HFS. Synovial inflammation occurred at Week 4 after joint trauma and instability but only coincided with pain behaviors after joint trauma. Cartilage and bone histopathology were most severe after joint destabilization and least severe with HFS. The pattern, intensity, and timing of evoked pain behaviors varied due to OA risk factor exposure and were inconsistently associated with histopathological OA features. These findings may help to explain the challenges with translating preclinical OA pain research to multimorbid clinical OA contexts.

COVID-19: mask efficacy is dependent on both fabric and fit.

Aim: Face masks are an important addition to our arsenal in the fight against COVID-19. The aim of this study is to present a novel method of measuring mask performance which can simultaneously assess both fabric penetration and leakage due to poor fit. Materials & methods: A synthetic aerosol is introduced into the lung of a medical dummy. A conical laser sheet surrounds the face of the dummy where it illuminates the aerosol emitted during a simulated breath. The system is demonstrated with five mask types. Conclusions: The curved laser sheet highlights both penetration through the mask fabric and leakage around the edges of the mask. A large variation in both material penetration and leakage was observed.

Terraforming: synthetic biology's final frontier.

Synthetic biology, the design and synthesis of synthetic biological systems from DNA to whole cells, has provided us with the ultimate tools for space exploration and colonisation. Herein, we explore some of the most significant advances and future prospects in the field of synthetic biology, in the context of astrobiology and terraforming.

Directed panspermia: a 21st century perspective.

Applying 21st century technology to the design and development of a hypothetical extra-terrestrial colonisation programme, we reimagine 'directed panspermia' from the perspective of Crick and Orgel's 'technological society', 44 years after the publication of their original landmark paper.