More on clinical and computed tomography characteristics of COVID-19 associated acute pulmonary embolism

Perioperative Medicine: Efficacy, Safety and Outcome (Anesthesiology/Intensive Care

Early effects of unfractionated heparin on clinical and radiological signs and D-dimer levels in patients with COVID-19 associated pulmonary embolism: an observational cohort study

Perioperative Medicine: Efficacy, Safety and Outcome (Anesthesiology/Intensive Care

Stability of mesocellular foam supported copper catalysts for methanol synthesis

Mesocellular foam is a well-defined mesoporous silica comprising large cages (˜20 nm), connected by small windows (2–10 nm). Here, we used mesocellular foam as a support material in the preparation of Cu based model catalyst for methanol synthesis at high temperature and pressure. To this end, we synthesized two types of mesocellular foam, with the same cage size, but a different window size of 8 and 2.3 nm, and compared them to the use of a silica gel support. Cu particles were deposited by impregnation with a copper nitrate precursor solution and decomposition in either N2 or H2-containing gas stream. We followed the phase evolution in situ, and identified a method using direct reduction in H2 to deposit 3 nm Cu particles on all different supports. The catalysts prepared on the mesocellular foam displayed a much higher stability than the silica gel supported catalysts. The impact of the window size of the MCF was small, but significant: the catalysts supported on the small window mesocellular foam were more stable on the long term. However, they also had a lower activity due to embedment of the Cu particles in the windows, as revealed with electron tomography. A higher metal loading on the small window mesocellular foam resulted in enhanced coalescence of the Cu particles, which was attributed to smaller interparticle distances. Increasing the loading on this support even further increased the size and polydispersity of the Cu nanoparticles, leading to a higher deactivation rate due to Ostwald ripening. Hence, the loading and size polydispersity are important parameters in determining the catalyst stability. We also found that the nature of the SiO2 support has more impact on the catalyst stability than the restricting pore sizes, probably due to the fact that Ostwald ripening dominates particle growth on the longer time scales

Stability of mesocellular foam supported copper catalysts for methanol synthesis

Mesocellular foam is a well-defined mesoporous silica comprising large cages (˜20 nm), connected by small windows (2–10 nm). Here, we used mesocellular foam as a support material in the preparation of Cu based model catalyst for methanol synthesis at high temperature and pressure. To this end, we synthesized two types of mesocellular foam, with the same cage size, but a different window size of 8 and 2.3 nm, and compared them to the use of a silica gel support. Cu particles were deposited by impregnation with a copper nitrate precursor solution and decomposition in either N2 or H2-containing gas stream. We followed the phase evolution in situ, and identified a method using direct reduction in H2 to deposit 3 nm Cu particles on all different supports. The catalysts prepared on the mesocellular foam displayed a much higher stability than the silica gel supported catalysts. The impact of the window size of the MCF was small, but significant: the catalysts supported on the small window mesocellular foam were more stable on the long term. However, they also had a lower activity due to embedment of the Cu particles in the windows, as revealed with electron tomography. A higher metal loading on the small window mesocellular foam resulted in enhanced coalescence of the Cu particles, which was attributed to smaller interparticle distances. Increasing the loading on this support even further increased the size and polydispersity of the Cu nanoparticles, leading to a higher deactivation rate due to Ostwald ripening. Hence, the loading and size polydispersity are important parameters in determining the catalyst stability. We also found that the nature of the SiO2 support has more impact on the catalyst stability than the restricting pore sizes, probably due to the fact that Ostwald ripening dominates particle growth on the longer time scales

Clinical and computed tomography characteristics of COVID-19 associated acute pulmonary embolism: A different phenotype of thrombotic disease?

Introduction: COVID-19 infections are associated with a high prevalence of venous thromboembolism, particularly pulmonary embolism (PE). It is suggested that COVID-19 associated PE represents in situ immunothrombosis rather than venous thromboembolism, although the origin of thrombotic lesions in COVID-19 patients remains largely unknown.Methods: In this study, we assessed the clinical and computed tomography (CT) characteristics of PE in 23 consecutive patients with COVID-19 pneumonia and compared these to those of 100 consecutive control patients diagnosed with acute PE before the COVID-19 outbreak. Specifically, RV/LV diameter ratio, pulmonary artery trunk diameter and total thrombus load (according to Qanadli score) were measured and compared.Results: We observed that all thrombotic lesions in COVID-19 patients were found to be in lung parenchyma affected by COVID-19. Also, the thrombus load was lower in COVID-19 patients (Qanadli score -8%, 95% confidence interval [95%CI] -16 to -0.36%) as was the prevalence of the most proximal PE in the main/lobar pulmonary artery (17% versus 47%; -30%, 95%CI -44% to -8.2). Moreover, the mean RV/LV ratio (mean difference -0.23, 95%CI -0.39 to -0.07) and the prevalence of RV/LV ratio > 1.0 (prevalence difference -23%, 95%CI -41 to -0.86%) were lower in the COVID-19 patients.Conclusion: Our findings therefore suggest that the phenotype of COVID-19 associated PE indeed differs from PE in patients without COVID-19, fuelling the discussion on its pathophysiology.Thrombosis and Hemostasi

ICONIC study—conservative versus conventional oxygenation targets in intensive care patients: study protocol for a randomized clinical trial

Background Oxygen therapy is a widely used intervention in acutely ill patients in the intensive care unit (ICU). It is established that not only hypoxia, but also prolonged hyperoxia is associated with poor patient-centered outcomes. Nevertheless, a fundamental knowledge gap remains regarding optimal oxygenation for critically ill patients. In this randomized clinical trial, we aim to compare ventilation that uses conservative oxygenation targets with ventilation that uses conventional oxygen targets with respect to mortality in ICU patients. Methods The “ConservatIve versus CONventional oxygenation targets in Intensive Care patients” trial (ICONIC) is an investigator-initiated, international, multicenter, randomized clinical two-arm trial in ventilated adult ICU patients. The ICONIC trial will run in multiple ICUs in The Netherlands and Italy to enroll 1512 ventilated patients. ICU patients with an expected mechanical ventilation time of more than 24 h are randomized to a ventilation strategy that uses conservative (PaO2 55–80 mmHg (7.3–10.7 kPa)) or conventional (PaO2 110–150 mmHg (14.7–20 kPa)) oxygenation targets. The primary endpoint is 28-day mortality. Secondary endpoints are ventilator-free days at day 28, ICU mortality, in-hospital mortality, 90-day mortality, ICU- and hospital length of stay, ischemic events, quality of life, and patient opinion of research and consent in the emergency setting. Discussion The ICONIC trial is expected to provide evidence on the effects of conservative versus conventional oxygenation targets in the ICU population. This study may guide targeted oxygen therapy in the future. Trial registration Trialregister.nl NTR7376. Registered on 20 July, 2018