Ambient Pressure Hydrodesulfurization of Refractory Sulfur Compounds in Highly Sensitive μ‑Reactor Platform Coupled to a Time-of-Flight Mass Spectrometer

Tightened restrictions call for cleaner transportation fuels to minimize environmental and societal problems caused by the presence of sulfur in transportation fuels. This emphasizes the need for new and better catalysts in the field of hydrodesulfurization (HDS), which aims at removing the refractory sulfur from different petroleum streams mostly found in the form of the alkyl-substituted dibenzothiophenes (β-DBTs). In this work we demonstrate how a setup dedicated to testing minute amounts (nanogram) of well-defined catalytic systems in μ-reactors can be used in the gas-phase HDS of the model compounds DBT and 4,6-dimethyldibenzothiophene (4,6-DMDBT) and the reaction pathways revealed by time-of-flight mass spectrometry. Specifically, we investigate HDS of DBT and 4,6-DMDBT on mass-selected Pt nanoparticles and show that only the direct desulfurization products are formed. The setup is a means to bridge the gap between structural characterization of model catalysts and their related activity in the HDS of DBT and 4,6-DMDBT

Engineering Ni–Mo–S Nanoparticles for Hydrodesulfurization

Nanoparticle engineering for catalytic applications requires both a synthesis technique for the production of well-defined nanoparticles and measurements of their catalytic performance. In this paper, we present a new approach to rationally engineering highly active Ni–Mo–S nanoparticle catalysts for hydrodesulfurization (HDS), i.e., the removal of sulfur from fossil fuels. Nanoparticle catalysts are synthesized by the sputtering of a Mo₇₅Ni₂₅ metal target in a reactive atmosphere of Ar and H₂S followed by the gas aggregation of the sputtered material into nanoparticles. The nanoparticles are filtered by a quadrupole mass filter and subsequently deposited on a planar substrate, such as a grid for electron microscopy or a microreactor. By varying the mass of the deposited nanoparticles, it is demonstrated that the Ni–Mo–S nanoparticles can be tuned into fullerene-like particles, flat-lying platelets, and upright-oriented platelets. The nanoparticle morphologies provide different abundances of Ni–Mo–S edge sites, which are commonly considered the catalytically important sites. Using a microreactor system, we assess the catalytic activity of the Ni–Mo–S nanoparticles for the HDS of dibenzothiophene. The measurements show that platelets are twice as active as the fullerene-like particles, demonstrating that the Ni–Mo–S edges are more active than basal planes for the HDS. Furthermore, the upright-standing orientation of platelets show an activity that is six times higher than the fullerene-like particles, demonstrating the importance of the edge site number and accessibility to reducing, e.g., sterical hindrance for the reacting molecules

Reversal strategies for non-vitamin K antagonist oral anticoagulants:a critical appraisal of available evidence and recommendations for clinical management - a joint position paper of the European Society of Cardiology Working Group on Cardiovascular Pharmacotherapy and European Society of Cardiology Working Group on Thrombosis

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Pantoprazole in patients at risk for gastrointestinal bleeding in the ICU

BACKGROUND Prophylaxis for gastrointestinal stress ulceration is frequently given to patients in the intensive care unit (ICU), but its risks and benefits are unclear. METHODS In this European, multicenter, parallel-group, blinded trial, we randomly assigned adults who had been admitted to the ICU for an acute condition (i.e., an unplanned admission) and who were at risk for gastrointestinal bleeding to receive 40 mg of intravenous pantoprazole (a proton-pump inhibitor) or placebo daily during the ICU stay. The primary outcome was death by 90 days after randomization. RESULTS A total of 3298 patients were enrolled; 1645 were randomly assigned to the pantoprazole group and 1653 to the placebo group. Data on the primary outcome were available for 3282 patients (99.5%). At 90 days, 510 patients (31.1%) in the pantoprazole group and 499 (30.4%) in the placebo group had died (relative risk, 1.02; 95% confidence interval [CI], 0.91 to 1.13; P=0.76). During the ICU stay, at least one clinically important event (a composite of clinically important gastrointestinal bleeding, pneumonia, Clostridium difficile infection, or myocardial ischemia) had occurred in 21.9% of patients assigned to pantoprazole and 22.6% of those assigned to placebo (relative risk, 0.96; 95% CI, 0.83 to 1.11). In the pantoprazole group, 2.5% of patients had clinically important gastrointestinal bleeding, as compared with 4.2% in the placebo group. The number of patients with infections or serious adverse reactions and the percentage of days alive without life support within 90 days were similar in the two groups. CONCLUSIONS Among adult patients in the ICU who were at risk for gastrointestinal bleeding, mortality at 90 days and the number of clinically important events were similar in those assigned to pantoprazole and those assigned to placebo. (Funded by Innovation Fund Denmark and others; SUP-ICU ClinicalTrials.gov number, NCT02467621.