Conjunctival epithelial cells resist productive SARS-CoV-2 infection.

Conjunctival epithelial cells, which express viral-entry receptors angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine type 2 (TMPRSS2), constitute the largest exposed epithelium of the ocular surface tissue and may represent a relevant viral-entry route. To address this question, we generated an organotypic air-liquid-interface model of conjunctival epithelium, composed of basal, suprabasal, and superficial epithelial cells, and fibroblasts, which could be maintained successfully up to day 75 of differentiation. Using single-cell RNA sequencing (RNA-seq), with complementary imaging and virological assays, we observed that while all conjunctival cell types were permissive to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome expression, a productive infection did not ensue. The early innate immune response to SARS-CoV-2 infection in conjunctival cells was characterised by a robust autocrine and paracrine NF-κB activity, without activation of antiviral interferon signalling. Collectively, these data enrich our understanding of SARS-CoV-2 infection at the human ocular surface, with potential implications for the design of preventive strategies and conjunctival transplantation.

Teaching Ultrasound at the Point of Care in Times of Social Distancing.

Point-of-care ultrasound has become an integral aspect of critical care training. The Bedside Assessment by Sonography In Critical Care Medicine Curriculum was established at the University of Toronto to train critical care trainees in basic echocardiography and general critical care ultrasound. During the coronavirus disease (COVID-19) pandemic, our program needed to adapt quickly to ensure staff safety and adherence to infection-control protocols. In this article, we share our experience and reflect on the challenges and benefits of shifting from a primarily in-person teaching model to a hybrid model of remote and in-person teaching. Curricular changes were threefold: the transition to entirely web-based interactive didactic teaching and online imaging interpretation modules, the recruitment of sonographers at multiple academic sites as instructors to facilitate in-person practices with lower instructor to trainee ratio, and the use of a mobile application for informal group case-based discussions. Challenges included lost opportunities for scanning healthy volunteers, variability in attendance at online lectures, and a lower number of study submissions for review. However, curricular changes enabled maintenance of directly observed practice, high levels of engagement with recorded content, and an expansion of our reach to a global audience. We believe that future curricula should combine high-quality online curriculum and resources with the ongoing in-person delivery of key elements of curriculum to allow for direct observation and feedback as well as the maintenance of self-directed point-of-care ultrasound portfolios.

COVID-19 Impact on Acute Ischemic Stroke Treatment at 9 Comprehensive Stroke Centers across Los Angeles.

OBJECTIVE: To describe the impact of COVID-19 on acute cerebrovascular disease care across 9 comprehensive stroke centers throughout Los Angeles County (LAC). METHODS: Volume of emergency stroke code activations, patient characteristics, stroke severity, reperfusion rates, treatment times, and outcomes from February 1 to April 30, 2020, were compared against the same time period in 2019. Demographic data were provided by each participating institution. RESULTS: There was a 17.3% decrease in stroke code activations across LAC in 2020 compared to 2019 (1,786 vs. 2,159, respectively, χ2 goodness of fit test p < 0.0001) across 9 participating comprehensive stroke centers. Patients who did not receive any reperfusion therapy decreased by 16.6% in 2020 (1,527) compared to 2019 (1,832). Patients who received only intravenous thrombolytic (IVT) therapy decreased by 31.8% (107 vs. 157). Patients who received only mechanical thrombectomy (MT) increased by 3% (102 vs. 99). Patients who received both IVT and MT decreased by 31.8% (45 vs. 66). Recanalization treatment times in 2020 were comparable to 2019. CSCs serving a higher proportion of Latinx populations in the eastern parts of LAC experienced a higher incidence of MT in 2020 compared to 2019. Mild increase in stroke severity was seen in 2020 compared to 2019 (8.95 vs. 8.23, p = 0.046). A higher percentage of patients were discharged home in 2020 compared to 2019 (59.5 vs. 56.1%, p = 0.034), a lower percentage of patients were discharged to skilled nursing facility (16.1 vs. 20.7%, p = 0.0004), and a higher percentage of patients expired (8.6 vs. 6.3%, p = 0.008). CONCLUSION: LAC saw a decrease in overall stroke code activations in 2020 compared to 2019. Reperfusion treatment times remained comparable to prepandemic metrics. There has been an increase in severe stroke incidence and higher volume of thrombectomy treatments in Latinx communities within LAC during the pandemic of 2020. More patients were discharged home, less patients discharged to skilled nursing facilities, and more patients expired in 2020, compared to the same time frame in 2019.

Fossil CO₂ emissions in the post-COVID-19 era

Five years after the adoption of the Paris Climate Agreement, growth in global CO2 emissions has begun to falter. The pervasive disruptions from the COVID-19 pandemic have radically altered the trajectory of global CO2 emissions. Contradictory effects of the post-COVID-19 investments in fossil fuel-based infrastructure and the recent strengthening of climate targets must be addressed with new policy choices to sustain a decline in global emissions in the post-COVID-19 era.Growth in CO2 emissions has slowed since the Paris Agreement 5 years ago. The COVID-19 pandemic has caused a drop in emissions of about 7% in 2020 relative to 2019, but strong policy is needed to address underlying drivers and to sustain a decline in global emissions beyond the current crisis.

Global Carbon Budget 2020

Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate – the “global carbon budget” – is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesize data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (EFOS) are based on energy statistics and cement production data, while emissions from land-use change (ELUC), mainly deforestation, are based on land use and land-use change data and bookkeeping models. Atmospheric CO2 concentration is measured directly and its growth rate (GATM) is computed from the annual changes in concentration. The ocean CO2 sink (SOCEAN) and terrestrial CO2 sink (SLAND) are estimated with global process models constrained by observations. The resulting carbon budget imbalance (BIM), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the last decade available (2010–2019), EFOS was 9.6 ± 0.5 GtC yr-1 excluding the cement carbonation sink (9.4 ± 0.5 GtC yr-1 when the cement carbonation sink is included), andELUC was 1.6 ± 0.7 GtC yr-1. For the same decade, GATM was 5.1 ± 0.02 GtC yr-1 (2.4 ± 0.01 ppm yr-1), SOCEAN 2.5 ± 0.6 GtC yr-1, and SLAND 3.4 ± 0.9 GtC yr-1, with a budget imbalance BIM of -0.1 GtC yr-1 indicating a near balance between estimated sources and sinks over the last decade. For the year 2019 alone, the growth in EFOS was only about 0.1 % with fossil emissions increasing to 9.9 ± 0.5 GtC yr-1 excluding the cement carbonation sink (9.7 ± 0.5 GtC yr-1 when cement carbonation sink is included), and ELUC was 1.8 ± 0.7 GtC yr-1, for total anthropogenic CO2 emissions of 11.5 ± 0.9 GtC yr-1 (42.2 ± 3.3 GtCO2). Also for 2019, GATM was 5.4 ± 0.2 GtC yr-1 (2.5 ± 0.1 ppm yr-1), SOCEAN was 2.6 ± 0.6 GtC yr-1, and SLAND was 3.1 ± 1.2 GtC yr-1, with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 409.85 ± 0.1 ppm averaged over 2019. Preliminary data for 2020, accounting for the COVID-19-induced changes in emissions, suggest a decrease in EFOS relative to 2019 of about -7 % (median estimate) based on individual estimates from four studies of -6 %, -7 %,-7 % (-3 % to -11 %), and -13 %. Overall, the mean and trend in the components of the global carbon budget are consistently estimated over the period 1959–2019, but discrepancies of up to 1 GtC yr-1 persist for the representation of semi-decadal variability in CO2 fluxes. Comparison of estimates from diverse approaches and observations shows (1) no consensus in the mean and trend in land-use change emissions over the last decade, (2) a persistent low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) an apparent discrepancy between the different methods for the ocean sink outside the tropics, particularly in the Southern Ocean. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this data set (Friedlingstein et al., 2019;Le Quéré et al., 2018b, a, 2016, 2015b, a, 2014, 2013). The data presented in this work are available at 10.18160/gcp-2020 (Friedlingstein et al., 2020).