Tuning Mesopore Accessibility of Ce_0.18Zr_0.64Y_0.15La_0.03O_2−δ by Hydrothermal Post-treatmentA Case Study for Ceria-Based Oxidation Storage Materials

The connectivity and thermal stability of pores in heterogeneous, mesoporous metal oxide catalysts are key properties controlling their (long-term) efficacy. In this study, we investigate the influence of pH and temperature during a common hydrothermal aftertreatment step in the synthesis of mesoporous CexZr1–x–y–zYyLazO2−δ oxides obtained from molecular precursors via hydrothermal synthesis. This study has a strong focus on the methodological approach, elucidating whether and how even the smallest changes in morphology and connectivity may be unraveled and related to the underlying chemical processes to uncover key parameters for the ongoing improvement of material properties. Deep insights into the mesopore space were obtained by state-of-the-art physisorption (including hysteresis scanning), electron tomography, and small-angle X-ray scattering (SAXS) analysis. We also provide a simple tool to simulate SAXS curves from electron tomography data that allow direct comparison to experimentally obtained SAXS curves. Furthermore, the impact on surface-bound nitrate groups and the development during calcination were studied in detail by thermogravimetric analysis coupled with mass spectrometry. The key observations indicate a significant increase in thermal stability at temperatures as high as 1050 °C and improved mesopore accessibility with an increase in pH of the aftertreatment solution. The combined observations from the employed methods suggest a pH-dependent removal of surface-bound nitrate groups as well as a dissolution and reprecipitation-based fusing of the primary particles that constitute the mesopore skeleton. This transformation yields a mechanically and thermally stronger mesopore space with the capability to endure high temperatures

Acute kidney disease beyond day 7 after major surgery: a secondary analysis of the EPIS-AKI trial

Purpose: Acute kidney disease (AKD) is a significant health care burden worldwide. However, little is known about this complication after major surgery. Methods: We conducted an international prospective, observational, multi-center study among patients undergoing major surgery. The primary study endpoint was the incidence of AKD (defined as new onset of estimated glomerular filtration rate (eCFR) < 60 ml/min/1.73 m2 present on day 7 or later) among survivors. Secondary endpoints included the relationship between early postoperative acute kidney injury (AKI) (within 72 h after major surgery) and subsequent AKD, the identification of risk factors for AKD, and the rate of chronic kidney disease (CKD) progression in patients with pre-existing CKD. Results: We studied 9510 patients without pre-existing CKD. Of these, 940 (9.9%) developed AKD after 7 days of whom 34.1% experiencing an episode of early postoperative-AKI. Rates of AKD after 7 days significantly increased with the severity (19.1% Kidney Disease Improving Global Outcomes [KDIGO] 1, 24.5% KDIGO2, 34.3% KDIGO3; P < 0.001) and duration (15.5% transient vs 38.3% persistent AKI; P < 0.001) of early postoperative-AKI. Independent risk factors for AKD included early postoperative-AKI, exposure to perioperative nephrotoxic agents, and postoperative pneumonia. Early postoperative-AKI carried an independent odds ratio for AKD of 2.64 (95% confidence interval [CI] 2.21-3.15). Of 663 patients with pre-existing CKD, 42 (6.3%) had worsening CKD at day 90. In patients with CKD and an episode of early AKI, CKD progression occurred in 11.6%. Conclusion: One in ten major surgery patients developed AKD beyond 7 days after surgery, in most cases without an episode of early postoperative-AKI. However, early postoperative-AKI severity and duration were associated with an increased rate of AKD and early postoperative-AKI was strongly associated with AKD independent of all other potential risk factors

Observation of B(s)0→J/ψpp‾B^0_{(s)} \to J/\psi p \overline{p} decays and precision measurements of the B(s)0B^0_{(s)} masses

International audienceThe first observation of the decays B(s)0→J/ψpp¯ is reported, using proton-proton collision data corresponding to an integrated luminosity of 5.2  fb-1, collected with the LHCb detector. These decays are suppressed due to limited available phase space, as well as due to Okubo-Zweig-Iizuka or Cabibbo suppression. The measured branching fractions are B(B0→J/ψpp¯)=[4.51±0.40(stat)±0.44(syst)]×10-7, B(Bs0→J/ψpp¯)=[3.58±0.19(stat)±0.39(syst)]×10-6. For the Bs0 meson, the result is much higher than the expected value of O(10-9). The small available phase space in these decays also allows for the most precise single measurement of both the B0 mass as 5279.74±0.30(stat)±0.10(syst)  MeV and the Bs0 mass as 5366.85±0.19(stat)±0.13(syst)  MeV