Ventilation Efficiency According to Tilt Angle to Reduce the Transmission of Infectious Disease in Classroom

Understanding of the droplet transmission of respiratory diseases is necessary to control the outbreak of COVID-19. HVAC systems considering droplet transmission are commonly used to prevent numerous respiratory diseases by reducing indoor virus concentrations. The transmission of the virus was directly related to indoor flow patterns generated by HVAC systems. Thus, a study on operating conditions such as direction or the tilt angle was required. In this study, the effective ventilation rate and probability of droplet transmission according to the tilt angle of supply air and the number of people were studied. A CO2 tracer gas method was used to validate the results of simulations. The breathing plane and personal respiratory zone were introduced for the probability of droplet transmission. The result showed that ventilation performance showed 17% of the maximum difference among tilt angles. Various turbulent kinetic energies were obtained according to the seated positions, resulting in non-uniform CO2 concentration. Numerous conditions were examined with locational analysis of individuals. As a result, the flow rates for ventilation were recommended to be higher than 250 m3/h and 350 m3/h with a tilt angle of 60degree for an occupancy of 8 and 16 people, respectively.Copyright © The Author(s) 2022.

Autoimmunity, immunosuppressive therapy and risk for COVID-19 pneumonitis among subjects with interstitial lung disease

Introduction: The impact of the SARS-CoV-2 virus on patients with interstitial lung disease (ILD) remains poorly understood. As patients with ILD often have severe underlying lung parenchymal involvement, and immunosuppressive therapy is common in this population, they are presumed to be at high risk for severe COVID-19 pneumonitis. We investigated clinical differences between those with ILD who tested positive for the SARS-CoV-2 virus compared to those with ILD who did not, and explored the relationship with use of immunosuppressive therapy. Methods: In this retrospective cohort study, we identified patients evaluated at the University of Chicagoin 2020 who were enrolled in the ILD registry, and stratified by SARS-CoV-2 seropositive status. We then compared baseline clinical characteristics between SARSCoV- 2 seropositive and SARS-CoV-2 seronegative patients and assessed immunosuppressive therapy at time of COVID diagnosis. C-reactive protein (CRP) and leukocyte subsets were evaluated at COVID diagnosis compared to time of baseline ILD evaluation. Variable comparisons were determined by two-sided t-tests, or chi-square tests as appropriate, and logistic regression models were fitted to assess the odds of death from COVID-19 using generalized linear models with maximum-likelihood estimation.Results: 309 subjects with ILD were included in this analysis, of which 21 patients had a confirmed SARS-CoV-2 infection (6.8%). Patients with SARS-CoV-2 were younger (55 yrs vs. 66 yrs;P=0.006) , had similar baseline leukocyte counts (9.4 vs 8.6;P=0.569) and demonstrated a trend towards a lower CRP (4.9 vs9.3;P=0.068) when compared to those without. Subjects with SARS-CoV-2 and ILD were more likely to have a diagnosis of autoimmune related-ILD (CTD-ILD or IPAF) (71% vs 39%;P=0.004), higher baseline lymphocyte fraction of circulating leukocytes (29% vs. 21%;P=0.025);greater prevalence of honeycomb fibrosis (43 vs. 21%;P=0.044), and were more frequently hypoxemic [SpO2<92%] (20% vs. 4%;P=0.009) at ILD diagnosis. The majority (62%) of patients with SARS-CoV-2 virus were on immunosuppressive therapy at time of diagnosis. Although, CRP titers were higher at diagnosis of COVID pneumonitis than at ILD diagnosis (52mg/L vs. 5mg/L;P=0.006), the lymphocyte fraction of circulating leukocytes did not differ (24% vs 28%;P=0.52)(Fig.1). Further, subjects with ILD and SARS-CoV-2 had higher odds of death than those without SARS-CoV-2 (OR=24, 95% CI-4-152;P<0.001). Conclusion: SARS-CoV-2 is prevalent in ILD, and may put those who are younger, with autoimmune ILD, and on immunosuppressive therapy at higher risk. Larger studies are needed to fully explore the relationship between ILD and immunosuppressive therapy in COVID-19. .

Carbon nanotube-paper composite-capacitive sensor for respiratory monitoring

Recent COVID-19 pandemic highlights the importance of monitoring and prediction of acute respiratory illness. Few options are available for convenient respiratory monitoring in both hospital and community settings. This paper presents a novel respiratory monitoring sensor made of carbon nanotube-paper composites (CPC). A CPC capacitive sensor fabricated with tensional fracture consists of numerous cellulose fibers coated with carbon nanotubes (CNTs). The high aspect ratio structure significantly enhances the capacitive sensitivity due to the high electric field. A CPC-wearable sensor is characterized in comparison to a sensor made of aluminum electrodes followed by monitoring of respiratory efforts. © 2020 CBMS-0001