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Structure–activity relationships built on descriptors of bulk and bulk-terminated surfaces are the basis for the rational design of electrocatalysts. However, electrochemically driven surface transformations complicate the identification of such descriptors. Here we demonstrate how the as-prepared surface composition of (001)-terminated LaNiO 3 epitaxial thin films dictates the surface transformation and the electrocatalytic activity for the oxygen evolution reaction. Specifically, the Ni termination (in the as-prepared state) is considerably more active than the La termination, with overpotential differences of up to 150 mV. A combined electrochemical, spectroscopic and density-functional theory investigation suggests that this activity trend originates from a thermodynamically stable, disordered NiO 2 surface layer that forms during the operation of Ni-terminated surfaces, which is kinetically inaccessible when starting with a La termination. Our work thus demonstrates the tunability of surface transformation pathways by modifying a single atomic layer at the surface and that active surface phases only develop for select as-synthesized surface terminations. Structure–activity relationships built on descriptors of surfaces can help to design electrocatalysts, but their identification for electrochemically driven surface transformations is challenging. The composition of LaNiO 3 thin film surfaces can now dictate surface transformation and activity of the oxygen evolution reaction.

Structure–activity relationships built on descriptors of bulk and bulk-terminated surfaces are the basis for the rational design of electrocatalysts. However, electrochemically driven surface transformations complicate the identification of such descriptors. In this work, we demonstrate how the as-prepared surface composition of (001)-terminated LaNiO3 epitaxial thin films dictates the surface transformation and the electrocatalytic activity for the oxygen evolution reaction. Specifically, the Ni termination (in the as-prepared state) is considerably more active than the La termination, with overpotential differences of up to 150 mV. A combined electrochemical, spectroscopic and density-functional theory investigation suggests that this activity trend originates from a thermodynamically stable, disordered NiO2 surface layer that forms during the operation of Ni-terminated surfaces, which is kinetically inaccessible when starting with a La termination. Our work thus demonstrates the tunability of surface transformation pathways by modifying a single atomic layer at the surface and that active surface phases only develop for select as-synthesized surface terminations.

Structure-activity relationships built on descriptors of bulk and bulk-terminated surfaces are the basis for the rational design of electrocatalysts. However, electrochemically driven surface transformations complicate the identification of such descriptors. Here we demonstrate how the as-prepared surface composition of (001)-terminated LaNiO epitaxial thin films dictates the surface transformation and the electrocatalytic activity for the oxygen evolution reaction. Specifically, the Ni termination (in the as-prepared state) is considerably more active than the La termination, with overpotential differences of up to 150 mV. A combined electrochemical, spectroscopic and density-functional theory investigation suggests that this activity trend originates from a thermodynamically stable, disordered NiO surface layer that forms during the operation of Ni-terminated surfaces, which is kinetically inaccessible when starting with a La termination. Our work thus demonstrates the tunability of surface transformation pathways by modifying a single atomic layer at the surface and that active surface phases only develop for select as-synthesized surface terminations.

Electrocatalysts are the cornerstone in the transition to sustainable energy technologies and chemical processes. Surface transformations under operation conditions dictate the activity and stability. However, the dependence of the surface structure and transformation on the exposed crystallographic facet remains elusive, impeding rational catalyst design. We investigate the (001), (110) and (111) facets of a LaNiO 3− δ electrocatalyst for water oxidation using electrochemical measurements, X-ray spectroscopy, and density functional theory calculations with a Hubbard U term. We reveal that the (111) overpotential is ≈ 30−60 mV lower than for the other facets. While a surface transformation into oxyhydroxide-like NiOO(H) may occur for all three orientations, it is more pronounced for (111). A structural mismatch of the transformed layer with the underlying perovskite for (001) and (110) influences the ratio of Ni 2+ and Ni 3+ to Ni 4+ sites during the reaction and thereby the binding energy of reaction intermediates, resulting in the distinct catalytic activities of the transformed facets. The development of active and stable catalysts for water splitting requires understanding of the surface transformations that occur during the reaction. Here, the authors report how the transformations and the activity depend on the exposed crystal facet using spectroscopy and ab initio calculations.

IntroductionPreclinical studies consistently show robust disease-modifying effects of intermittent fasting in animal models of cardiovascular disease. However, the impact of intermittent fasting on cardiovascular endpoints after myocardial infarction has not been investigated in a clinical trial so far.Methods and analysisThe INTERmittent FASTing after Myocardial Infarction (INTERFAST-MI) trial is a monocentric prospective randomised controlled non-confirmatory pilot study including 48 patients with ST-segment elevation myocardial infarction. They will be randomised in a 1:1 ratio to either intermittent fasting (daily time-restricted eating; consuming food for not more than 8 hours/day, fasting for at least 16 hours/day) or to a control group without a particular diet. The follow-up time is 6 months. The prespecified primary outcome is change in left ventricular systolic function at 4 weeks from baseline to estimate effect size required to establishing sample size and power calculation for a future full-scale trial. Secondary outcomes include protocol adherence, recruitment, major adverse cardiac events, revascularisation, changes in left ventricular systolic function at 3 and 6 months, patient weight, blood pressure, and serum markers of inflammation and cardiovascular disease. Enrolment began on 1 November 2020 and is expected to conclude in December 2021.Ethics and disseminationThe trial has received ethics approval from the Medical Ethics Committee of the Martin-Luther-University Halle-Wittenberg. Results of the study will be submitted for publication in a peer-reviewed journal and presented at scientific conferences.Trial registration numberDRKS00021784.

A single missense mutation at position 159 of coenzyme Q9 (COQ9) (G→A; rs109301586) has been associated with genetic variation in fertility in Holstein cattle, with the A allele associated with higher fertility. COQ9 is involved in the synthesis of coenzyme COQ10, a component of the electron transport system of the mitochondria. Here we tested whether reproductive phenotype is associated with the mutation and evaluated functional consequences for cellular oxygen metabolism, body weight changes, and ovarian function. The mutation in COQ9 modifies predicted tertiary protein structure and affected mitochondrial respiration of peripheral blood mononuclear cells. The A allele was associated with low resting oxygen consumption and high electron transport system capacity. Phenotypic measurements for fertility were evaluated for up to five lactations in a population of 2273 Holstein cows. There were additive effects of the mutation (P < 0.05) in favor of the A allele for pregnancy rate, interval from calving to conception, and services per conception. There was no association of genotype with milk production or body weight changes postpartum. The mutation in COQ9 affected ovarian function; the A allele was associated with increased mitochondrial DNA copy number in oocytes, and there were overdominance effects for COQ9 expression in oocytes, follicle number, and antimullerian hormone concentrations. Overall, results show how a gene involved in mitochondrial function is associated with overall fertility, possibly in part by affecting oocyte quality. Summary Sentence A SNP in COQ9 was described that changes predicted protein structure, is associated with altered mitochondrial afunction, and that modulates reproductive function in dairy cattle, possibly by regulating oocyte quality.

Drought alters carbon (C) allocation within trees, thereby impairing tree growth. Recovery of root and leaf functioning and prioritized C supply to sink tissues after drought may compensate for droughtinduced reduction of assimilation and growth. It remains unclear if C allocation to sink tissues during and following drought is controlled by altered sink metabolic activities or by the availability of new assimilates. Understanding such mechanisms is required to predict forests’ resilience to a changing climate.We investigated the impact of drought and drought release on C allocation in a 100-y-old Scots pine forest. We applied 13CO₂ pulse labeling to naturally dry control and long-term irrigated trees and tracked the fate of the label in above- and belowground C pools and fluxes. Allocation of new assimilates belowground was ca. 53% lower under nonirrigated conditions. A short rainfall event, which led to a temporary increase in the soil water content (SWC) in the topsoil, strongly increased the amounts of C transported belowground in the nonirrigated plots to values comparable to those in the irrigated plots. This switch in allocation patterns was congruent with a tipping point at around 15% SWC in the response of the respiratory activity of soil microbes. These results indicate that the metabolic sink activity in the rhizosphere and its modulation by soil moisture can drive C allocation within adult trees and ecosystems. Even a subtle increase in soil moisture can lead to a rapid recovery of belowground functions that in turn affects the direction of C transport in trees.

Climate change exposes ecosystems to strong and rapid changes in their environmental boundary conditions mainly due to the altered temperature and precipitation patterns. It is still poorly understood how fast interlinked ecosystem processes respond to altered environmental conditions, if these responses occur gradually or suddenly when thresholds are exceeded, and if the patterns of the responses will reach a stable state. We conducted an irrigation experiment in the Pfynwald, Switzerland from 2003–2018. A naturally dry Scots pine (Pinus sylvestris L.) forest was irrigated with amounts that doubled natural precipitation, thus releasing the forest stand from water limitation. The aim of this study was to provide a quantitative understanding on how different traits and functions of individual trees and the whole ecosystem responded to increased water availability, and how the patterns and magnitudes of these responses developed over time. We found that the response magnitude, the temporal trajectory of responses, and the length of initial lag period prior to significant response largely varied across traits. We detected rapid and stronger responses from aboveground tree traits (e.g., tree-ring width, needle length, and crown transparency) compared to belowground tree traits (e.g., fine-root biomass). The altered aboveground traits during the initial years of irrigation increased the water demand and trees adjusted by increasing root biomass during the later years of irrigation, resulting in an increased survival rate of Scots pine trees in irrigated plots. The irrigation also stimulated ecosystem-level foliar decomposition rate, fungal fruit body biomass, and regeneration abundances of broadleaved tree species. However, irrigation did not promote the regeneration of Scots pine trees, which are reported to be vulnerable to extreme droughts. Our results provide extensive evidence that treeand ecosystem-level responses were pervasive across a number of traits on long-term temporal scales. However, after reaching a peak, the magnitude of these responses either decreased or reached a new stable state, providing important insights into how resource alterations could change the system functioning and its boundary conditions.