Here, we compare analogous cyclic and acyclic π-conjugated molecules as n-type electronic materials and find that the cyclic molecules have numerous benefits in organic photovoltaics. This is the first report of such a direct comparison. We designed two conjugated cycles for this study. Each comprises four subunits: one combines four electron-accepting, redox-active, diphenyl-perylenediimide subunits, and the other alternates two electron-donating bithiophene units with two diphenyl-perylenediimide units. We compare the macrocycles to acyclic versions of these molecules and find that, relative to the acyclic analogs, the conjugated macrocycles have bathochromically shifted UV-vis absorbances and are more easily reduced. In blended films, macrocycle-based devices show higher electron mobility and good morphology. All of these factors contribute to the more than doubling of the power conversion efficiency observed in organic photovoltaic devices with these macrocycles as the n-type, electron transporting material. This study highlights the importance of geometric design in creating new molecular semiconductors. The ease with which we can design and tune the electronic properties of these cyclic structures charts a clear path to creating a new family of cyclic, conjugated molecules as electron transporting materials in optoelectronic and electronic devices.

Background The COVID-19 pandemic has magnified existing health disparities for marginalized populations in the United States (U.S.), particularly among Black Americans. Social determinants of health are powerful drivers of health outcomes that could influence COVID-19 racial disparities. Methods We collected data from publicly available databases on COVID-19 death rates through October 28, 2020, clinical covariates, and social determinants of health indicators at the U.S. county level. We utilized negative binomial regression to assess the association between social determinants of health and COVID-19 mortality focusing on racial disparities in mortality. Results Counties with higher death rates had a higher proportion of Black residents and greater levels of adverse social determinants of health. A one percentage point increase in percent Black residents, percent uninsured adults, percent low birthweight, percent adults without high school diploma, incarceration rate, and percent households without internet in a county increased COVID-19 death rates by 0.9% (95% CI 0.5%-1.3%), 1.9% (95% CI 1.1%-2.7%), 7.6% (95% CI 4.4%-11.0%), 3.5% (95% CI 2.5%-4.5%), 5.4% (95% CI 1.3%-9.7%), and 3.4% (95% CI 2.5%-4.2%), respectively. Counties in the lowest quintile of a measure of economic privilege had an increased COVID-19 death rates of 67.5% (95% CI 35.9%-106.6%). Multivariate regression and subgroup analyses suggested that adverse social determinants of health may partially explain racial disparities in COVID-19 mortality. Conclusions This study demonstrates that social determinants of health contribute to COVID-19 mortality for Black Americans at the county level, highlighting the need for public health policies that address racial disparities in health outcomes.

This work presents an experimental investigation of enhancing surface plasmon polariton coupling to semiconductor emission by tailoring metal film thickness.

BackgroundIncreased demand for endovascular thrombectomy has increased the likelihood of simultaneous patient presentation leading to competing demand for time-critical treatment that could adversely impact patient outcomes. We aimed to quantify the occurrence of simultaneous patient presentation at different patient volumes.MethodsEmpirical distributions for time of patient presentation and case duration were used to probabilistically generate arrival time and case duration for a set annual patient volume, ranging from 1 to 500 cases per year, for 16 000 independent trials at each volume. Time series were generated for each trial to represent the number of cases being performed at each minute of the year. Time series were used to calculate daily thrombectomy demand, annual concurrent demand, and hourly excess demand.ResultsThe patient volumes at which at least one annual occurrence of concurrent demand by two patients was 50% and 97.5% likely were 45 and 101, respectively. The volumes at which at least one annual occurrence of concurrent demand by three patients was 50% and 97.5% likely were 216 and 387, respectively. There was dramatic variation in the occurrence of excess demand by two or more patients throughout the day.ConclusionsThe occurrence of simultaneous presentation by multiple patients for endovascular thrombectomy varies with annual patient volume and time of day. Understanding these trends and the associated patient impact can inform intelligent strategies at regional and national levels for optimizing patient care within real-world financial and operational constraints.

BackgroundThe rise in demand for endovascular thrombectomy (EVT) has increased the possibility that multiple patients with acute ischemic stroke may present concurrently and exceed local capacity to provide timely treatment. In this work, we quantitatively compared the efficacy of various strategies to mitigate demand in excess of capacity (DEC).MethodsStrategies evaluated included a backup neurointerventional team for 3 hours, 8 hours, or 24 hours per day; a separate pre-intervention imaging team; and a 30% decrease in procedure duration. For each strategy, empirical distributions were used to probabilistically generate arrival time and case duration for 16 000 independent trials repeated across a range of annual case volumes. DEC was calculated from time series representing the number of concurrent cases at each minute of the year for each trial at each case volume.ResultsAll strategies decreased DEC compared with baseline. At a representative volume of 250 cases per year, availability of a backup team for 3 hours, 8 hours, and 24 hours per day reduced DEC by 27.0%, 60.3%, and 97.2%, respectively, compared with baseline. Similarly, availability of a pre-intervention imaging team and a 30% decrease in procedure duration reduced DEC by 26.6% and 17.7%, respectively, compared with baseline.ConclusionsA backup neurointerventional team, even if available only part time, was an effective strategy for decreasing DEC for EVT. Understanding the actual quantitative benefit of each strategy can facilitate rational cost–benefit analyses underlying the development of efficient and sustainable models of care.