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Background The devastating Coronavirus disease (COVID-19) pandemic is associated with a high prothrombotic state. It is unclear if the coagulation abnormalities occur because of the direct effect of SARS-CoV-2 or indirectly by the cytokine storm and endothelial damage or by a combination of mechanisms. There is a clear indication of in-hospital pharmacological thromboprophylaxis for every patient with COVID-19 after bleed risk assessment. However, there is much debate regarding the best dosage regimen, and there is no consensus on the role of extended thromboprophylaxis. Design This study aims to evaluate the safety and efficacy of rivaroxaban 10 mg once daily for 35±4 days versus no intervention after hospital discharge in COVID-19 patients who were at increased risk for VTE and have received standard parenteral VTE prophylaxis during hospitalization. The composite efficacy endpoint is a combination of symptomatic VTE, VTE-related death, VTE detected by bilateral lower limbs venous duplex scan and computed tomography pulmonary angiogram on day 35±4 post-hospital discharge and symptomatic arterial thromboembolism (myocardial infarction [MI], non-hemorrhagic stroke, major adverse limb events [MALE] and cardiovascular [CV] death) up to day 35±4 post-hospital discharge. The key safety outcome is the incidence of major bleeding according to ISTH criteria. Summary The MICHELLE trial is expected to provide high-quality evidence around the role of extended thromboprophylaxis in COVID-19 and will help guide medical decisions in clinical practice.

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Production of alternative fuels, such as biodiesel, from transesterification of vegetable oil driven by heterogeneous catalysts is a promising alternative to fossil diesel. However, achieving a successful substitution for a new renewable fuel depends on several quality parameters. (1)H NMR spectroscopy was used to determine the amount of methyl esters, free glycerin and acid number in the transesterification of soybean oil with methanol in the presence of hydrotalcite-type catalyst to produce biodiesel. Reaction parameters, such as temperature and time, were used to evaluate soybean oil methyl esters rate conversion. Temperatures of 100 to 180 °C and times of 20 to 240 min were tested on a 1 : 12 molar ratio soybean oil/methanol reaction. At 180 °C/240 min conditions, a rate of 94.5 wt% of methyl esters was obtained, where free glycerin and free fatty acids were not detected.

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Two synthetic solid-solution series, analcime to Rb-leucite and analcime to Cs-leucite (pollucite), have been investigated to understand more fully the thermodynamic and structural behavior of analcime-leucite and similar mineral systems. Unit-cell dimensions and volumes in these series expand with the substitution of analcime component in either Rb-leucite or pollucite, as H 2 O molecules structurally replace the smaller entities Rb +1 or Cs +1 , respectively. Unit-cell volumes vary linearly as functions of composition, but with changing slopes over several segments of compositional space, akin to thermal expansion in K-, Rb-, and Cs-end-member materials studied by previous workers. When symmetry changes displacively from tetragonal to isometric, as in the Rb-bearing series, the slope of volume expansion changes. Once structures have reached full expansion, volume slopes flatten and are little affected by additional analcime component. Enthalpies of solution measured at 50 ∞C in 20.1 wt% hydrofluoric acid show single-slope linear relationships over the entire compositional ranges of both series. Thus, despite positive volumes of mixing, there are no enthalpies of mixing in either series, nor is there energetic evidence of displacive tetragonal/isometric inversion or the various stages of structural expansion. Overall, the data suggest that the analcime-leucite system also can be modeled as close to thermodynamically ideal. The limited solid solution between natural analcime and leucite must be attributed to energetically favored heterogeneous equilibria involving minerals such as feldspars and other feldspathoids, and not to immiscibility between the end-members.

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