Validated computational modelling to evaluate spatial inactivation of airborne pathogens by Far-UVC irradiation.

Recent experimental studies have indicated the potential for ultraviolet-C irradiation at 222nm (Far-UVC) to be used in occupied rooms to safely reduce exposure to airborne pathogens. We present simulations applying a Monte Carlo radiation transfer model with a computational fluid dynamics model to predict the spatial variation in airborne microorganism inactivation. Our simulations effectively reproduce data from steady state experiments in a room-sized bio-aerosol chamber for the reduction of aerosolised Staphylococcus aureus. Application of the validated model suggests that germicidal Far-UVC lamps could reduce levels of airborne human coronavirus by more than 90% in rooms with low ventilation rates. The inactivation of pathogens by Far-UVC is more efficient than previously thought, due to the complex path that particles take within the three dimensional airflow and UVC irradiance pattern. Depending on the UVC-susceptibility of the aerosolised pathogen, Far-UVC lamps have the potential to provide effective room air change rates in excess of 100 equivalent air changes per hour, much greater than is possible with mechanical ventilation or filtration devices. The success of our simulations at reproducing the experimental data provides confidence that we can simulate larger environments and inform best practices for installations of germicidal Far-UVC lamps.

Improved and optimized drug repurposing for the SARS-CoV-2 pandemic.

The active global SARS-CoV-2 pandemic caused more than 426 million cases and 5.8 million deaths worldwide. The development of completely new drugs for such a novel disease is a challenging, time intensive process. Despite researchers around the world working on this task, no effective treatments have been developed yet. This emphasizes the importance of drug repurposing, where treatments are found among existing drugs that are meant for different diseases. A common approach to this is based on knowledge graphs, that condense relationships between entities like drugs, diseases and genes. Graph neural networks (GNNs) can then be used for the task at hand by predicting links in such knowledge graphs. Expanding on state-of-the-art GNN research, Doshi et al. recently developed the Dr-COVID model. We further extend their work using additional output interpretation strategies. The best aggregation strategy derives a top-100 ranking of 8,070 candidate drugs, 32 of which are currently being tested in COVID-19-related clinical trials. Moreover, we present an alternative application for the model, the generation of additional candidates based on a given pre-selection of drug candidates using collaborative filtering. In addition, we improved the implementation of the Dr-COVID model by significantly shortening the inference and pre-processing time by exploiting data-parallelism. As drug repurposing is a task that requires high computation and memory resources, we further accelerate the post-processing phase using a new emerging hardware-we propose a new approach to leverage the use of high-capacity Non-Volatile Memory for aggregate drug ranking.

Turn Up the Lights, Leave them On and Shine them All Around-Numerical Simulations Point the Way to more Efficient Use of Far-UVC Lights for the Inactivation of Airborne Coronavirus.

It has been demonstrated in laboratory environments that ultraviolet-C (UVC) light is effective at inactivating airborne viruses. However, due to multiple parameters, it cannot be assumed that the air inside a room will be efficiently disinfected by commercial germicidal ultraviolet (GUV) systems. This research utilizes numerical simulations of airflow, viral spread, inactivation by UVC and removal by mechanical ventilation in a typical classroom. The viral load in the classroom is compared for conventional upper-room GUV and the emerging "Far-UVC." In our simulated environment, GUV is shown to be effective in both well and poorly ventilated rooms, with greatest benefit in the latter. At current exposure limits, 18 commercial Far-UVC systems were as effective at reducing viral load as a single upper-room GUV. Improvements in Far-UVC irradiation distribution and recently proposed increases to exposure limits would dramatically increase the efficacy of Far-UVC devices. Modifications to current Far-UVC devices, which would improve their real-world efficacy, could be implemented now without requiring legislative change. The prospect of increased safety limits coupled with our suggested technological modifications could usher in a new era of safe and rapid whole room air disinfection in occupied indoor spaces.

A worldwide assessment of changes in adherence to COVID-19 protective behaviours and hypothesized pandemic fatigue.

As the COVID-19 pandemic lingers, the possibility of 'pandemic fatigue' has raised worldwide concerns. Here, we examine whether there was a gradual reduction in adherence to protective behaviours against COVID-19 from March through December 2020, as hypothesized in expectations of fatigue. We considered self-report behaviours from representative samples of the populations of 14 countries (N = 238,797), as well as mobility and policy data for 124 countries. Our results show that changes in adherence were empirically meaningful and geographically widespread. While a low-cost and habituating behaviour (mask wearing) exhibited a linear rise in adherence, high-cost and sensitizing behaviours (physical distancing) declined, but this decline decelerated over time, with small rebounds seen in later months. Reductions in adherence to physical distancing showed little difference across societal groups, but were less intense in countries with high interpersonal trust. Alternative underlying mechanisms and policy implications are discussed.

Financial Integration's Impact On Care Delivery And Payment Reforms: A Survey Of Hospitals And Physician Practices.

Health systems continue to grow in size. Financial integration-the ownership of hospitals or physician practices-often has anticompetitive effects that contribute to the higher prices for health care seen in the US. To determine whether the potential harms of financial integration are counterbalanced by improvements in quality, we surveyed nationally representative samples of hospitals (n = 739) and physician practices (n = 2,189), stratified according to whether they were independent or were owned by complex systems, simple systems, or medical groups. The surveys included nine scales measuring the level of adoption of diverse, quality-focused care delivery and payment reforms. Scores varied widely across hospitals and practices, but little of this variation was explained by ownership status. Quality scores favored financially integrated systems for four of nine hospital measures and one of nine practice measures, but in no case favored complex systems. Greater financial integration was generally not associated with better quality.