Biomarkers of coagulation, endothelial function, and fibrinolysis in critically ill patients with COVID-19: A single-center prospective longitudinal study

Background: Immunothrombosis and coagulopathy in the lung microvasculature may lead to lung injury and disease progression in coronavirus disease 2019 (COVID-19). We aim to identify biomarkers of coagulation, endothelial function, and fibrinolysis that are associated with disease severity and may have prognostic potential. Methods: We performed a single-center prospective study of 14 adult COVID-19(+) intensive care unit patients who were age- and sex-matched to 14 COVID-19(−) intensive care unit patients, and healthy controls. Daily blood draws, clinical data, and patient characteristics were collected. Baseline values for 10 biomarkers of interest were compared between the three groups, and visualized using Fisher\u27s linear discriminant function. Linear repeated-measures mixed models were used to screen biomarkers for associations with mortality. Selected biomarkers were further explored and entered into an unsupervised longitudinal clustering machine learning algorithm to identify trends and targets that may be used for future predictive modelling efforts. Results: Elevated D-dimer was the strongest contributor in distinguishing COVID-19 status; however, D-dimer was not associated with survival. Variable selection identified clot lysis time, and antigen levels of soluble thrombomodulin (sTM), plasminogen activator inhibitor-1 (PAI-1), and plasminogen as biomarkers associated with death. Longitudinal multivariate k-means clustering on these biomarkers alone identified two clusters of COVID-19(+) patients: low (30%) and high (100%) mortality groups. Biomarker trajectories that characterized the high mortality cluster were higher clot lysis times (inhibited fibrinolysis), higher sTM and PAI-1 levels, and lower plasminogen levels. Conclusions: Longitudinal trajectories of clot lysis time, sTM, PAI-1, and plasminogen may have predictive ability for mortality in COVID-19

Through the Lens of a Camera: Exploring the Meaning of Competitive Sport Participation Among Youth Athletes with Disabilities

This study explores the meaning of competitive sports participation among youth athletes with disabilities who are members of a sled hockey team affiliated with a community-based therapeutic recreation (TR) and adaptive sports organization. The study draws upon theories of Social Role Valorization and Perceived Freedom in Leisure, and employs the Socio-Ecological Model to (a) examine the role of adaptive sports programs as bridging organizations, mediating the space between individual capacities, collective identities, and valued social roles for youth with disabilities; and (b) identify barriers and enablers of participation. Photovoice was employed utilizing the template analytic method. Findings suggest that competitive sports participation: (1) facilitates identification with valued social roles, (2) supports outcomes associated with Perceived Freedom in Leisure, and (3) empowers youth with disabilities to discuss barriers and enablers to social inclusion. This study highlights the role of Photovoice as a tool for informing TR and adaptive sport practice, and facilitatin

Scramjet experiments in an expansion tunnel: Evaluated using a quasi- steady analysis technique

As scramjet engine development moves toward higher and higher speeds, it will be important to continue to ground test complete nose-to-tail configurations at true flight conditions. Above Mach 10, the freestream total pressure requirements can only be met by an expansion-tube facility. To establish the practicality of ground-testing complete scramjet configurations at high Mach numbers, an expansion-tunnel facility is used to test a generic two-dimensional scramjet at a Mach 10 replication condition. As the flow produced in an expansion-tube facility is transient in nature, a method for analyzing point measurements within the scramjet is developed. A transient numerical simulation of the engine configuration without fuel injection is used to verify the validity of the technique, as well as to provide a reference data set for comparison to experimental data. These experiments show that stable supersonic combustion is established during the test time. Using the developed transient analysis, accurate quasi-steady pressure data at true flight conditions can be inferred from scramjet test measurements in an expansion-tube facility

Effects of Upstream Injection on Scramjet Performance Using an Entropy-Based Method

Upstream injection has the potential for increasing the overall performance of a scramjet by reducing the overall length required to complete combustion and, thereby, reducing overall vehicle frictional drug. However, high flow losses will be incurred by injecting a fuel on the inlet where the Mach number is high. A simple overall approach based on entropy generation was used to investigate the effect or flow losses oil overall performance. This showed that the injection flow losses can he quite high for upstream injection when compared with conventional combustor injection. An inviseid analysis of a two-dimensional scramjet at a Mach 10 flight condition found that a significant loss In overall performance of the engine occurs if the bulk of injection is undertaken on the intake. Estimates of viscous effects in a scramjet combustor showed that depending on the reduction of the mixing length achieved in the combustor, the upstream injection flow losses could he substantially recovered, making it an advantageous design option. The analysis technique developed, like similar simple analysis methodologies, provides a useful understanding of the physical processes that influence thrust production and can also be used to quickly evaluate and optimize potential configurations before starting detailed flow-field simulations