Prospective observational cohort study of the association between antiplatelet therapy, bleeding and thrombosis in patients with coronary stents undergoing noncardiac surgery

Background: The perioperative management of antiplatelet therapy in noncardiac surgery patients who have undergone previous percutaneous coronary intervention (PCI) remains a dilemma. Continuing dual antiplatelet therapy (DAPT) may carry a risk of bleeding, while stopping antiplatelet therapy may increase the risk of perioperative major adverse cardiovascular events (MACE). Methods: Occurrence of Bleeding and Thrombosis during Antiplatelet Therapy In Non-Cardiac Surgery (OBTAIN) was an international prospective multicentre cohort study of perioperative antiplatelet treatment, MACE, and serious bleeding in noncardiac surgery. The incidences of MACE and bleeding were compared in patients receiving DAPT, monotherapy, and no antiplatelet therapy before surgery. Unadjusted risk ratios were calculated taking monotherapy as the baseline. The adjusted risks of bleeding and MACE were compared in patients receiving monotherapy and DAPT using propensity score matching. Results: A total of 917 patients were recruited and 847 were eligible for inclusion. Ninety-six patients received no antiplatelet therapy, 526 received monotherapy with aspirin, and 225 received DAPT. Thirty-two patients suffered MACE and 22 had bleeding. The unadjusted risk ratio for MACE in patients receiving DAPT compared with monotherapy was 1.9 (0.93–3.88), P=0.08. There was no difference in MACE between no antiplatelet treatment and monotherapy 1.03 (0.31–3.46), P=0.96. Bleeding was more frequent with DAPT 6.55 (2.3–17.96) P=0.0002. In a propensity matched analysis of 177 patients who received DAPT and 177 monotherapy patients, the risk ratio for MACE with DAPT was 1.83 (0.69–4.85), P=0.32. The risk of bleeding was significantly greater in the DAPT group 4.00 (1.15–13.93), P=0.031. Conclusions: OBTAIN showed an increased risk of bleeding with DAPT and found no evidence for protective effects of DAPT from perioperative MACE in patients who have undergone previous PCI

Can the homogeneity scale be used as a standard ruler?

The Universe on comoving scales larger than 100 Mpc/h is assumed to be statistically homogeneous, with the transition scale where we have 1% deviation from homogeneity being known as the homogeneity scale RH. The latter was recently proposed in Ntelis et al. [J. Cosmol. Astropart. Phys. 12 (2018) 014JCAPBP1475-751610.1088/1475-7516/2018/12/014] to be a standard ruler. In this paper we perform a comparison between the baryon acoustic oscillations and the homogeneity scales RH, assuming a spatially universe, linear cosmological perturbation theory and the cosmological constant cold dark matter (ΛCDM) model. By direct theoretical calculations, we demonstrate that the answer to the question of whether the homogeneity scale can be used as a standard ruler is clearly negative due to the nonmonotonicity of the homogeneity scale RH with the matter density parameter Ωm0 of the ΛCDM model. Furthermore, we also consider the effect of redshift-space distortions and we find that they do not break the degeneracies but instead only change the value of RH by a few percent. Finally, we also confirm our findings with the help of an N-body simulation

Power Plant Cycles: Evolution towards More Sustainable and Environmentally Friendly Technologies

The scarcity of energy and water resources and rising temperatures due to climate change has set the focus on improving the energy efficiency of power plant thermodynamic cycles to adapt to higher heat sink temperatures and use fewer resources for energy production. In this work, a review of power production thermodynamic cycles is presented: from Brayton to Rankine and combined cycles, alongside particular cycles such as Organic Rankine Cycles, Kalina, Goswami or the more recently developed Hygroscopic Cycle. The efficiency of these cycles and their possible improvements are considered, as well as their environmental impact. Costs associated with existing power plants found in the literature have also been included in the study. The main existing facilities for each cycle type are assessed, and the most sustainable options in terms of resource consumption (fuel, water, etc.) and future perspectives to ensure both their energy efficiency and sustainability are identified