Investigation of isobutane dehydrogenation on CrO<inf>x</inf>/MCM-41 catalyst

The syntheses of MCM-41 (Mobil Composition of Matter No. 41) supported chromium oxide catalysts at different chromium concentrations (4-10 \% by mass) were carried out hydrothermally. The aim of this study was to determine the effect of chromium concentration in the catalyst structure on the chromate types and chromium oxidation states, as well as the activity of the catalyst in the isobutane dehydrogenation reaction. Inactive alpha-Cr2O3 crystals for isobutane dehydrogenation were shown to increase in the catalyst structure as the chromium loading increased. The highest amount of Cr6+ on the catalyst surface was detected in the catalyst (H4-MCM-41) with 4 \% chromium by mass. Catalytic tests (T = 600 degrees C, P = atmospheric pressure, WHSV = 26 h(-1)) were performed under fixed bed reactor conditions. The highest isobutane conversion (similar to 60 \%) and selectivity (similar to 80 \%) were observed on the H4-MCM-41 catalyst, which had the highest amount of Cr6+ and monochromate structures. Catalyst deactivation was not due to coke deposition but, rather, was caused by the formation of inactive alpha-Cr2O3 crystal structures

The factors predicting pneumonia in covid-19 patients: Preliminary results from a university hospital in Turkey

Background/aim: Pneumonia is the most serious clinical presentation of COVID-19. This study aimed to determine the demographic, clinical, and laboratory findings that can properly predict COVID-19 pneumonia. Materials and methods: This study was conducted in the Gazi University hospital. All hospitalized patients with confirmed and suspected SARS-CoV-2 infection between 16 March 2020 and 30 April 2020 were analyzed retrospectively. COVID-19 patients were separated into two groups, pneumonia and nonpneumonia, and then compared to determine predicting factors for COVID-19 pneumonia. Variables that had a P-value of less than 0.20 and were not correlated with each other were included in the logistic regression model. Results: Of the 247 patients included in the study 58\% were female, and the median age was 40. COVID-19 was confirmed in 70.9\% of these patients. Among the confirmed COVID-19 cases, 21.4\% had pneumonia. In the multivariate analysis male sex (P = 0.028), hypertension (P = 0.022), and shortness of breath on hospital admission (P = 0.025) were significant factors predicting COVID-19 pneumonia. Conclusion: Shortness of breath, male sex, and hypertension were significant for predicting COVID-19 pneumonia on admission. Patients with these factors should be evaluated more carefully for diagnostic procedures, such as thorax CT