Co_3O_4 Nanoparticle Water-Oxidation Catalysts Made by Pulsed-Laser Ablation in Liquids

Surfactant-free, size- and composition-controlled, unsupported, <5-nm, quantum-confined cobalt oxide nanoparticles with high electrocatalytic oxygen-evolution activity were synthesized by pulsed laser ablation in liquids. These crystalline Co_3O_4 nanoparticles have a turnover frequency per cobalt surface site among the highest ever reported for Co_3O_4 nanoparticle oxygen evolution catalysts in base and overpotentials competitive with the best electrodeposited cobalt oxides, with the advantage that they are suitable for mechanical deposition on photoanode materials and incorporation in integrated solar water-splitting devices

Co₃O₄ Nanoparticle Water-Oxidation Catalysts Made by Pulsed-Laser Ablation in Liquids

Surfactant-free, size- and composition-controlled, unsupported, <5-nm, quantum-confined cobalt oxide nanoparticles with high electrocatalytic oxygen-evolution activity were synthesized by pulsed laser ablation in liquids. These crystalline Co₃O₄ nanoparticles have a turnover frequency per cobalt surface site among the highest ever reported for Co₃O₄ nanoparticle oxygen evolution catalysts in base and overpotentials competitive with the best electrodeposited cobalt oxides, with the advantage that they are suitable for mechanical deposition on photoanode materials and incorporation in integrated solar water-splitting devices

Highly Active Mixed-Metal Nanosheet Water Oxidation Catalysts Made by Pulsed-Laser Ablation in Liquids

Surfactant-free mixed-metal hydroxide water oxidation nanocatalysts were synthesized by pulsed-laser ablation in liquids. In a series of [Ni-Fe]-layered double hydroxides with intercalated nitrate and water, [Ni_1–<i>x</i>Fe_<i>x</i>(OH)₂]­(NO₃)_<i>y</i>(OH)_{<i>x</i>−<i>y</i>}·<i>n</i>H₂O, higher activity was observed as the amount of Fe decreased to 22%. Addition of Ti⁴⁺ and La³⁺ ions further enhanced electrocatalysis, with a lowest overpotential of 260 mV at 10 mA cm^–2. Electrocatalytic water oxidation activity increased with the relative proportion of a 405.1 eV N 1s (XPS binding energy) species in the nanosheets

Experimental and Computational Study of BODIPY Dye-Labeled Cavitand Dynamics

Understanding the distance distribution and dynamics between moieties attached to the walls of a resorcin[4]­arene cavitand, which is switchable between an expanded kite and a contracted vase form, might enable the use of this molecular system for the study of fundamental distance-dependent interactions. Toward this goal, a combined experimental and molecular dynamics (MD) simulation study on donor/acceptor borondipyrromethene (BODIPY) dye-labeled cavitands present in the vase and kite forms was performed. Direct comparison between anisotropy decays calculated from MD simulations with experimental fluorescence anisotropy data showed excellent agreement, indicating that the simulations provide an accurate representation of the dynamics of the system. Distance distributions between the BODIPY dyes were established by comparing time-resolved Förster resonance energy transfer experiments and MD simulations. Fluorescence intensity decay curves emulated on the basis of the MD trajectories showed good agreement with the experimental data, suggesting that the simulations present an accurate picture of the distance distributions and dynamics in this molecular system and provide an important tool for understanding the behavior of extended molecular systems and designing future applications

Parameterization of Thermal Properties of Aging Secondary Organic Aerosol Produced by Photo-Oxidation of Selected Terpene Mixtures

Formation and evolution of secondary organic aerosols (SOA) from biogenic VOCs influences the Earth’s radiative balance. We have examined the photo-oxidation and aging of boreal terpene mixtures in the SAPHIR simulation chamber. Changes in thermal properties and chemical composition, deduced from mass spectrometric measurements, were providing information on the aging of biogenic SOA produced under ambient solar conditions. Effects of precursor mixture, concentration, and photochemical oxidation levels (OH exposure) were evaluated. OH exposure was found to be the major driver in the long term photochemical transformations, i.e., reaction times of several hours up to days, of SOA and its thermal properties, whereas the initial concentrations and terpenoid mixtures had only minor influence. The volatility distributions were parametrized using a sigmoidal function to determine <i>T</i>_VFR0.5 (the temperature yielding a 50% particle volume fraction remaining) and the steepness of the volatility distribution. <i>T</i>_VFR0.5 increased by 0.3 ± 0.1% (ca. 1 K), while the steepness increased by 0.9 ± 0.3% per hour of 1 × 10⁶ cm^–3 OH exposure. Thus, aging reduces volatility and increases homogeneity of the vapor pressure distribution, presumably because highly volatile fractions become increasingly susceptible to gas phase oxidation, while less volatile fractions are less reactive with gas phase OH

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) &lt; 60&nbsp;ml/min/1.73&nbsp;m2 present on day 7 or later) among survivors. Secondary endpoints included the relationship between early postoperative acute kidney injury (AKI) (within 72&nbsp;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&nbsp;days of whom 34.1% experiencing an episode of early postoperative-AKI. Rates of AKD after 7&nbsp;days significantly increased with the severity (19.1% Kidney Disease Improving Global Outcomes [KDIGO] 1, 24.5% KDIGO2, 34.3% KDIGO3; P &lt; 0.001) and duration (15.5% transient vs 38.3% persistent AKI; P &lt; 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&nbsp;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