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Plant-based diets (PBDs) and planetary-health diets (PHDs) are recommended for their potential health and environmental benefits, but population-based evidence in diverse cultures is scarce.

Climate change can significantly impact agriculture, leading to food security challenges. Most previous studies have investigated the direct climate impact on crops while neglecting the impact of heat stress on agricultural labor. Here, we assess the economic consequences of climate impacts on four major crops—maize, soybean, wheat, and rice—for scenarios involving low and high greenhouse gas emissions. Our analysis is based on the output from a new generation of global climate and crop models to drive a multiregional economic model. We find that, even under a high-emission scenario, the effect of CO2fertilization could lead to higher yields, resulting in lower prices for major crops, except for maize. However, heat-induced losses in agricultural labor could offset the potential economic benefits of CO2fertilization in crop production in Asia and Africa. Our findings emphasize the importance of addressing heat-stress impacts on agricultural labor through proactive adaptation measures.

Understanding the underlying mechanisms of soil microbial nitrogen (N) utilization under land use change is critical to evaluating soil N availability or limitation and its environmental consequences. A combination of soil gross N production and ecoenzymatic stoichiometry provides a promising avenue for nutrient limitation assessment in soil microbial metabolism. Gross N production via 15N tracing and ecoenzymatic stoichiometry through the vector and threshold element ratio (Vector-TER) model were quantified to evaluate the soil microbial N limitation in response to land use changes. We used tropical soil samples from a natural forest ecosystem and three managed ecosystems (paddy, rubber, and eucalyptus sites). Soil extracellular enzyme activities were significantly lower in managed ecosystems than in a natural forest. The Vector-TER model results indicated microbial carbon (C) and N limitations in the natural forest soil, and land use change from the natural forest to managed ecosystems increased the soil microbial N limitation. The soil microbial N limitation was positively related to gross N mineralization (GNM) and nitrification (GN) rates. The decrease in microbial biomass C and N as well as hydrolyzable ammonium N in managed ecosystems led to the decrease in N-acquiring enzymes, inhibiting GNM and GN rates and ultimately increasing the microbial N limitation. Soil GNM was also positively correlated with leucine aminopeptidase and β-N-acetylglucosaminidase. The results highlight that converting tropical natural forests to managed ecosystems can increase the soil microbial N limitation through reducing the soil microbial biomass and gross N production.

Ga-based propane dehydrogenation (PDH) catalysts are explored in industry as an alternative to PtSn and CrOx-based catalysts. Yet, at present, there is only limited understanding of the structural dynamics of surface sites in Ga-based PDH catalysts. Here, we employ atomic layer deposition (ALD) to engineer a sub-monolayer of Ga species on dehydroxylated silica, which serves as a model PDH catalyst. While the ALD-grown shell contains, after calcination at 500 °C, tetra- and pentacoordinate Ga3+sites with both Si and Ga atoms in the second coordination sphere (i.e., [4]Ga(Si/Ga)and [5]Ga(Si/Ga)sites), its exposure to ambient air leads to sub-nanometer GaxOy(OH)zclusters with [4]Ga(Ga)and [6]Ga(Ga)sites, due to the hydrolysis of the Ga–O–Si linkages by the moisture of ambient air. When calcining the material at 650 °C, the [4]Ga(Ga)and [6]Ga(Ga)sites evolve leading to a silica surface dominated by isolated tetracoordinate [4]Ga(4Si)sites, that is, [(SiO)3Ga(XOSi)] sites, where X is H or Si. Exposure of the dehydroxylated material with [4]Ga(4Si)sites to ambient air reforms the sub-nanometer GaxOy(OH)zclusters, indicating the reversibility of the Ga dispersion and agglomeration as a function of the extent of silica (de)hydroxylation. The presence of [4]Ga(4Si)sites coincides with a high performance in PDH, achieving an initial turnover frequency of ca.12 h−1and propene selectivity of ca.85%, while deactivating by only 34% over 20 h of time on stream. Overall, our results highlight the dynamic nature of the dispersion and agglomeration of Ga3+sites during the dehydroxylation (by calcination) and rehydration (ambient air exposure).

Aufgrund der gestiegenen Bedeutung von Nachhaltigkeit wird diese als strategisches Unternehmensziel immer relevanter. Bisher genutzte Kennzahlen sind jedoch für die zur Zielerreichung notwendige Operationalisierung von Nachhaltigkeit im Sinne der in der Literatur definierten Anforderungen ungeeignet. Deshalb wird in diesem Beitrag die Annahme einer neuen Hilfskennzahl, der sogenannten Flächenproduktivität, vorgestellt, die sowohl Nachhaltigkeit valide und gesamtheitlich wiedergibt als auch die weiteren Anforderungen in Form von Benutzerfreundlichkeit und Wirtschaftlichkeit erfüllt und sich damit zur Verhaltenssteuerung in Unternehmen eignet.

This work provides insight into the local structure of Na in MgO-based CO2sorbents that are promoted with NaNO3. To this end, we use X-ray absorption spectroscopy (XAS) at the Na K-edge to interrogate the local structure of Na during the CO2capture (MgO + CO2↔ MgCO3). The analysis of Na K-edge XAS data shows that the local environment of Na is altered upon MgO carbonation when compared to that of NaNO3in the as-prepared sorbent. We attribute the changes observed in the carbonated sorbent to an alteration in the local structure of Na at the NaNO3/MgCO3interfaces and/or in the vicinity of [Mg2+···CO32–] ionic pairs that are trapped in the cooled NaNO3melt. The changes observed are reversible, i.e., the local environment of NaNO3was restored after a regeneration treatment to decompose MgCO3to MgO. The ex situ Na K-edge XAS experiments were complemented by ex situ magic-angle spinning 23Na nuclear magnetic resonance (MAS 23Na NMR), Mg K-edge XAS and X-ray powder diffraction (XRD). These additional experiments support our interpretation of the Na K-edge XAS data. Furthermore, we develop in situ Na (and Mg) K-edge XAS experiments during the carbonation of the sorbent (NaNO3is molten under the conditions of the in situ experiments). These in situ Na K-edge XANES spectra of molten NaNO3open new opportunities to investigate the atomic scale structure of CO2sorbents modified with Na-based molten salts by using XAS.

Cryo-electron tomography (cryo-ET) allows for label-free high-resolution imaging of macromolecular assemblies in their native cellular context. However, the localization of macromolecules of interest in tomographic volumes can be challenging. Here we present a ligand-inducible labeling strategy for intracellular proteins based on fluorescent, 25-nm-sized, genetically encoded multimeric particles (GEMs). The particles exhibit recognizable structural signatures, enabling their automated detection in cryo-ET data by convolutional neural networks. The coupling of GEMs to green fluorescent protein-tagged macromolecules of interest is triggered by addition of a small-molecule ligand, allowing for time-controlled labeling to minimize disturbance to native protein function. We demonstrate the applicability of GEMs for subcellular-level localization of endogenous and overexpressed proteins across different organelles in human cells using cryo-correlative fluorescence and cryo-ET imaging. We describe means for quantifying labeling specificity and efficiency, and for systematic optimization for rare and abundant protein targets, with emphasis on assessing the potential effects of labeling on protein function.

CaO-based sorbents are cost-efficient materials for high-temperature CO2capture, yet they rapidly deactivate over carbonation-regeneration cycles due to sintering, hindering their utilization at the industrial scale. Morphological stabilizers such as Al2O3or SiO2(e.g., introduced via impregnation) can improve sintering resistance, but the sorbents still deactivate through the formation of mixed oxide phases and phase segregation, rendering the stabilization inefficient. Here, we introduce a strategy to mitigate these deactivation mechanisms by applying (Al,Si)Oxovercoats via atomic layer deposition onto CaCO3nanoparticles and benchmark the CO2uptake of the resulting sorbent after 10 carbonation-regeneration cycles against sorbents with optimized overcoats of only alumina/silica (+25%) and unstabilized CaCO3nanoparticles (+55%). 27Al and 29Si NMR studies reveal that the improved CO2uptake and structural stability of sorbents with (Al,Si)Oxovercoats is linked to the formation of glassy calcium aluminosilicate phases (Ca,Al,Si)Oxthat prevent sintering and phase segregation, probably due to a slower self-diffusion of cations in the glassy phases, reducing in turn the formation of CO2capture-inactive Ca-containing mixed oxides. This strategy provides a roadmap for the design of more efficient CaO-based sorbents using glassy stabilizers.

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The direct synthesis of methanol via the hydrogenation of CO2, if performed efficiently and selectively, is potentially a powerful technology for CO2mitigation. Here, we develop an active and selective Cu–Zn/SiO2catalyst for the hydrogenation of CO2by introducing copper and zinc onto dehydroxylated silica via surface organometallic chemistry and atomic layer deposition, respectively. At 230 °C and 25 bar, the optimized catalyst shows an intrinsic methanol formation rate of 4.3 g h–1gCu–1and selectivity to methanol of 83%, with a space-time yield of 0.073 g h–1gcat–1at a contact time of 0.06 s g mL–1. X-ray absorption spectroscopy at the Cu and Zn K-edges and X-ray photoelectron spectroscopy studies reveal that the CuZn alloy displays reactive metal support interactions; that is, it is stable under H2atmosphere and unstable under conditions of CO2hydrogenation, indicating that the dealloyed structure contains the sites promoting methanol synthesis. While solid-state nuclear magnetic resonance studies identify methoxy species as the main stable surface adsorbate, transient operando diffuse reflectance infrared Fourier transform spectroscopy indicates that μ-HCOO*(ZnOx) species that form on the Cu–Zn/SiO2catalyst are hydrogenated to methanol faster than the μ-HCOO*(Cu) species that are found in the Zn-free Cu/SiO2catalyst, supporting the role of Zn in providing a higher activity in the Cu–Zn system.

There is a fundamental issue with the use of dynamic nuclear polarization (DNP) to enhance nuclear spin polarization: the same polarizing agent (PA) needed for DNP is also responsible for shortening the lifetime of the hyperpolarization. As a result, long-term storage and transport of hyperpolarized samples is severely restricted and the apparatus for DNP is necessarily located near or integrated with the apparatus using the hyperpolarized spins. In this paper, we demonstrate that naphthalene single crystals can serve as a long-lived reservoir of proton polarization that can be exploited to enhance signals in benchtop and high-field NMR of target molecules in solution at a site 300 km away by a factor of several thousand. The naphthalene protons are polarized using short-lived optically excited triplet states of pentacene instead of stable radicals. In the absence of optical excitation, the electron spins remain in a singlet ground state, eliminating the major pathway of nuclear spin–lattice relaxation. The polarization decays with a time constant of about 50 h at 80 K and 0.5 T or above 800 h at 5 K and 20 mT. A module based on a Halbach array yielding a field of 0.75 T and a conventional cryogenic dry shipper, operating at liquid nitrogen temperature, allows storage and long distance transport of the polarization to a remote laboratory, where the polarization of the crystal is transferred after dissolution to a target molecule of choice by intermolecular cross-relaxation. The procedure has been executed repeatedly and has proven to be reliable and robust.

We present a versatile method for the preparation of hyperpolarized [1-13C]fumarate as a contrast agent for preclinical in vivoMRI, using parahydrogen-induced polarization (PHIP). To benchmark this process, we compared a prototype PHIP polarizer to a state-of-the-art dissolution dynamic nuclear polarization (d-DNP) system. We found comparable polarization, volume, and concentration levels of the prepared solutions, while the preparation effort is significantly lower for the PHIP process, which can provide a preclinical dose every 10 min, opposed to around 90 min for d-DNP systems. With our approach, a 100 mM [1-13C]-fumarate solution of volumes up to 3 mL with 13–20% 13C-hyperpolarization after purification can be produced. The purified solution has a physiological pH, while the catalyst, the reaction side products, and the precursor material concentrations are reduced to nontoxic levels, as confirmed in a panel of cytotoxicity studies. The in vivousage of the hyperpolarized fumarate as a perfusion agent in healthy mice and the metabolic conversion of fumarate to malate in tumor-bearing mice developing regions with necrotic cell death is demonstrated. Furthermore, we present a one-step synthesis to produce the 13C-labeled precursor for the hydrogenation reaction with high yield, starting from 13CO2as a cost-effective source for 13C-labeled compounds.

Hintergrund: Die Dermatoskopie stellt ein wichtiges Hilfsmittel in der allgemeinen Dermatologie dar. Ziel der Arbeit: Es erfolgt die Darstellung von Unterschieden von heller und dunkler Haut in nichtneoplastischen Erkrankungen mit Fokus auf die Dermatoskopie. Material und Methoden: Anhand von bisher publizierten Studien sollen dermatoskopische Unterschiede der unterschiedlichen Hauttypen sowie Merkmale von inflammatorischen Erkrankungen und Pigmentveränderungen erläutert werden. Ergebnisse: Bestimmte Strukturen sind in der Dermatoskopie dunkler Haut schwieriger zu beurteilen (z. B. Gefäße), während sich andere Strukturen (z. B. Follikelöffnungen) prominenter darstellen. Diskussion: Der Großteil der Studien zur Dermatoskopie stammt aus Studien, in denen vorwiegend Personen mit einem hellen Hauttyp inkludiert wurden. Weitere Studien mit Personen mit einem Hauttyp IV oder höher sind notwendig, um die Diagnostik in dieser Bevölkerungsgruppe zu verbessern.

Understanding of feedbacks between plant N uptake and soil N transformations in different vegetable production systems is crucial to increase vegetable N acquisition and improve N fertilizer management. 15N tracing pot experiments were conducted under greenhouse (GH) and open-field (OF) conditions; plant N uptake and soil gross N transformation rates were simultaneously quantified using the Ntraceplanttool. The feedbacks of plant N uptake on rhizosphere soil gross N transformations differed between GH and OF. Higher plant NH4+and NO3–uptake rates were observed in GH compared to OF, which were associated with higher plant biomass in GH. Rhizosphere soil mineral N production rates (i.e., the sum of mineralization and heterotrophic nitrification rates) in GH ranged from 0.18 to 1.53 mg N kg−1day−1and were significantly lower than in OF (0.60 to 4.56 mg N kg−1day−1). The reduced rhizosphere soil mineral N production rates in GH were attributed to high soil moisture conditions and vegetable activities (especially respiratory activity in rhizosphere). Rhizosphere soil microbial N immobilization rates in GH were 1.6–166.5 times lower compared to OF, which was line with decreased mineral N production rates and enhanced plant N uptake rates. This was also confirmed by the fact that the microbial N immobilization rates showed a negative correlation with the mineral N production rates and the N uptake rates of plants. We showed that the capacity of soil rhizospheric mineral N supply was weaker in GH than OF, which was one of the reasons why more N fertilizer was required to achieve rapid vegetable growth in greenhouse vegetable production. We also highlighted the importance of water management to improve rhizosphere soil N supply in greenhouse vegetable cultivation.

The response of soil gross nitrogen (N) cycling to elevated carbon dioxide (CO2) concentration and temperature has been extensively studied in natural and semi-natural ecosystems. However, how these factors and their interaction affect soil gross N dynamics in agroecosystems, strongly disturbed by human activity, remains largely unknown. Here, a 15N tracer study under aerobic incubation was conducted to quantify soil gross N transformation rates in a paddy field exposed to elevated CO2and/or temperature for 9 years in a warming and free air CO2enrichment experiment. Results show that long-term exposure to elevated CO2significantly inhibited or tended to inhibit gross N mineralization at elevated and ambient temperatures, respectively. The inhibition of soil gross N mineralization by elevating CO2was aggravated by warming in this paddy field. The inhibition of gross N mineralization under elevated CO2could be due to decreased soil pH. Long-term exposure to elevated CO2also significantly reduced gross autotrophic nitrification at ambient temperature, probably due to decreased soil pH and gross N mineralization. In contrast, none of the gross N transformation rates were affected by long-term exposure to warming alone. Our study provides strong evidence that long-term dual exposure to elevated CO2and temperature has a greater negative effect on gross N mineralization rate than the single exposure, potentially resulting in progressive N limitation in this agroecosystem and ultimately increasing demand for N fertilizer.

Heterogeneous catalysts are complex materials, often containing multiple atomic species and phases with various degrees of structural order. The identification of structure–performance relationships that rely on the availability of advanced structural characterization tools is key for rational catalyst design. Structural descriptors in catalysts can be defined over different length scales from several angstroms up to several nanometers (crystalline structure), requiring structural characterization techniques covering these different length scales. Pair distribution function (PDF) analysis is a powerful method to extract structural information spanning from the atomic to the nanoscale under in situor operandoconditions. We discuss recent advances using PDF to provide insight into the atomic-to-nanoscale structure of heterogeneous catalysts.

Maize (Zea maysL.) N uptake affects N use efficiency (NUE), which is affected by the N form for uptake. However, maize N preference for NH4+or NO3−is unclear. A field experiment and a 15N tracing study was conducted with various soils differing in pH plant with maize. Maize N (NO3−and NH4+) uptake rate significantly varied with soil pH, but NO3−uptake rate (UNO3) was much higher than NH4+uptake rate (UNH4) irrespectively of the pH, i.e., maize generally preferred NO3−uptake over NH4+at the seedling stage. The generally higher UNH4and UNO3in acidic compared to alkaline soils in the laboratory study were consistent with the maize yield in the field experiment results. The positive relationship between UNO3and UNH4(P< 0.01) indicated a synergistic effect between NH4+and NO3−uptake. The longer NH4+residence time could explain the higher NH4+and total N uptake rates in acidic soil than alkaline soil. With maize planted, the rate of autotrophic nitrification (ONH4) reduced between 30 and 75% compared to unplanted soils supporting N uptake via a prolonged NH4+residence time. The rate of heterotrophic nitrification (ONrec) was stimulated by maize plants, accounting for up to 45% of total NO3−production in acidic soils. The role of ONrecwas illustrated by a positive correlation of ONrec/(ONH4+ ONrec) with UNO3(P< 0.01). Maize seedling preferred NO3−over NH4+irrespectively of pH. Moreover, maize can regulate soil N supply through interactions between plant and soil N transformations to meet their N acquisition.

The eukaryotic transcription apparatus synthesizes a staggering diversity of RNA molecules. The labour of nuclear gene transcription is, therefore, divided among multiple DNA-dependent RNA polymerases. RNA polymerase I (Pol I) transcribes ribosomal RNA, Pol II synthesizes messenger RNAs and various non-coding RNAs (including long non-coding RNAs, microRNAs and small nuclear RNAs) and Pol III produces transfer RNAs and other short RNA molecules. Pol I, Pol II and Pol III are large, multisubunit protein complexes that associate with a multitude of additional factors to synthesize transcripts that largely differ in size, structure and abundance. The three transcription machineries share common characteristics, but differ widely in various aspects, such as numbers of RNA polymerase subunits, regulatory elements and accessory factors, which allows them to specialize in transcribing their specific RNAs. Common to the three RNA polymerases is that the transcription process consists of three major steps: transcription initiation, transcript elongation and transcription termination. In this Review, we outline the common principles and differences between the Pol I, Pol II and Pol III transcription machineries and discuss key structural and functional insights obtained into the three stages of their transcription processes.

Emissions of the critical ozone-depleting and greenhouse gas nitrous oxide (N2O) from soils and industrial processes have increased considerably over the last decades1–3. As the final step of bacterial denitrification, N2O is reduced to chemically inert N2(refs. 1,4) in a reaction that is catalysed by the copper-dependent nitrous oxide reductase (N2OR) (ref. 5). The assembly of its unique [4Cu:2S] active site cluster CuZrequires both the ATP-binding-cassette (ABC) complex NosDFY and the membrane-anchored copper chaperone NosL (refs. 4,6). Here we report cryo-electron microscopy structures of Pseudomonas stutzeriNosDFY and its complexes with NosL and N2OR, respectively. We find that the periplasmic NosD protein contains a binding site for a Cu+ion and interacts specifically with NosL in its nucleotide-free state, whereas its binding to N2OR requires a conformational change that is triggered by ATP binding. Mutually exclusive structures of NosDFY in complex with NosL and with N2OR reveal a sequential metal-trafficking and assembly pathway for a highly complex copper site. Within this pathway, NosDFY acts as a mechanical energy transducer rather than as a transporter. It links ATP hydrolysis in the cytoplasm to a conformational transition of the NosD subunit in the periplasm, which is required for NosDFY to switch its interaction partner so that copper ions are handed over from the chaperone NosL to the enzyme N2OR.

The recent crystallization of the neuropeptide Y Y1receptor (Y1R) in complex with the argininamide-type Y1R selective antagonist UR-MK299 (2) opened up a new approach toward structure-based design of nonpeptidic Y1R ligands. We designed novel fluorescent probes showing excellent Y1R selectivity and, in contrast to previously described fluorescent Y1R ligands, considerably higher (∼100-fold) binding affinity. This was achieved through the attachment of different fluorescent dyes to the diphenylacetyl moiety in 2via an amine-functionalized linker. The fluorescent ligands exhibited picomolar Y1R binding affinities (pKivalues of 9.36–9.95) and proved to be Y1R antagonists, as validated in a Fura-2 calcium assay. The versatile applicability of the probes as tool compounds was demonstrated by flow cytometry- and fluorescence anisotropy-based Y1R binding studies (saturation and competition binding and association and dissociation kinetics) as well as by widefield and total internal reflection fluorescence (TIRF) microscopy of live tumor cells, revealing that fluorescence was mainly localized at the plasma membrane.

Dissimilatory nitrate reduction to ammonium (DNRA), the nearly forgotten process in the terrestrial nitrogen (N) cycle, can conserve N by converting the mobile nitrate into non-mobile ammonium avoiding nitrate losses via denitrification, leaching, and runoff. However, global patterns and controlling factors of soil DNRA are still only rudimentarily known. By a meta-analysis of 231 observations from 85 published studies across terrestrial ecosystems, we find a global mean DNRA rate of 0.31 ± 0.05 mg N kg–1day–1, being significantly greater in paddy soils (1.30 ± 0.59) than in forests (0.24 ± 0.03), grasslands (0.52 ± 0.15), and unfertilized croplands (0.18 ± 0.04). Soil DNRA was significantly enhanced at higher altitude and lower latitude. Soil DNRA was positively correlated with precipitation, temperature, pH, soil total carbon, and soil total N. Precipitation was the main stimulator for soil DNRA. Total carbon and pH were also important factors, but their effects were ecosystem-specific as total carbon stimulates DNRA in forest soils, whereas pH stimulates DNRA in unfertilized croplands and paddy soils. Higher temperatures inhibit soil DNRA via decreasing total carbon. Moreover, nitrous oxide (N2O) emissions were negatively related to soil DNRA. Thus, future changes in climate and land-use may interact with management practices that alter soil substrate availability and/or soil pH to enhance soil DNRA with positive effects on N conservation and lower N2O emissions.

The influence of the phase of the ZrO2support (monoclinic, tetragonal, and amorphous, referred to as m-, t-, and am-, respectively) on the nature of the surface species involved in methanol synthesis and the rates of their formation on ZrO2-supported, In-based catalysts for CO2hydrogenation has been investigated. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) at 300 °C and 20 bar (H2:CO2:N2= 3:1:1 volume ratio) on m-ZrO2:In, In2O3/t-ZrO2, and In2O3/am-ZrO2catalysts (m-ZrO2:In is a solid solution) shows that formate species (HCOO*) appear prior to methoxy species (*OCH3), and both intermediates form faster on the more active m-ZrO2:In catalyst. Only formate bands are detected for the In2O3/t-ZrO2catalyst. For these materials, indium sites are essential for the formation of HCOO* and *OCH3species as only carbonate species are observed on m-, t-, and am-ZrO2supports under CO2hydrogenation conditions. The nature of the reaction intermediates is confirmed by ex situ solid-state nuclear magnetic resonance (NMR), where both methoxy and formate species are detected in m-ZrO2:In and In2O3/am-ZrO2, respectively, but only a weak formate peak is observed for In2O3/t-ZrO2. The presence of a major methoxy peak and only a very minor formate signal in unsupported In2O3indicates that an india–zirconia interface is required for the effective stabilization of formate species. Catalytic tests in a fixed bed reactor are consistent with both CO and MeOH being primary products of CO2hydrogenation; the tests also show that the methanol selectivity and space time yield decrease in the following order: m-ZrO2:In > In2O3/t-ZrO2> In2O3/am-ZrO2for all of the contact times tested.

This work explores how H2pretreatment at 550 °C induces structural transformation of two gallia-based propane dehydrogenation (PDH) catalysts, viz.nanocrystalline γ/β-Ga2O3and amorphous Ga2O3(GaOx) supported on silica (γ-Ga2O3/SiO2and Ga/SiO2, respectively) and how it affects their activity, propene selectivity and stability with time on stream (TOS). Ga/SiO2–H2shows poor activity and propene selectivity, no coking and no deactivation with TOS, similar to Ga/SiO2. In contrast, the high initial activity and propene selectivity of γ-Ga2O3/SiO2–H2decline with TOS but to a lesser extent than in calcined γ-Ga2O3/SiO2. In addition, γ-Ga2O3/SiO2–H2cokes less than γ-Ga2O3/SiO2. Ga K-edge X-ray absorption spectroscopy suggests an increased disorder of the nanocrystalline γ/β-Ga2O3phases in γ-Ga2O3/SiO2–H2and the emergence of additional tetrahedral Ga sites (GaIV). Such GaIVsites are strong Lewis acid sites (LAS) according to studies using adsorbed pyridine and CO probe molecules, i.e., the abundance of strong LAS is higher in γ-Ga2O3/SiO2–H2compared to γ-Ga2O3/SiO2but lower than in Ga/SiO2and Ga/SiO2–H2. Dissociation of H2on the Ga–O linkages in γ-Ga2O3/SiO2–H2yields high-frequency Ga–H bands that are observed in Ga/SiO2and Ga/SiO2–H2but not detected in γ-Ga2O3/SiO2. We attribute the increased amount of GaIVsites in γ-Ga2O3/SiO2–H2mostly to an increased disorder in γ/β-Ga2O3. X-ray photoelectron spectroscopy detects the formation of Ga+and Ga0species in both Ga/SiO2–H2and γ-Ga2O3/SiO2–H2. Therefore, it is likely that a minor amount of GaIVsites also forms through the interaction of Ga+(such as Ga2O) and/or Ga0with silanol groups of SiO2.

Catalysts with well-defined isolated Ni(ii) surface sites have been prepared on three silica-based supports. The outer shells of the support were comprised either of an amorphous aluminosilicate or amorphous alumina (AlOx) layer – associated with a high and low density of strong Brønsted acid sites (BAS), respectively. When tested for ethene-to-propene conversion, Ni catalysts with a higher density of strong BAS demonstrate a higher initial activity and productivity to propene. On all three catalysts, the propene productivity correlates closely with the concentration of C8aromatics, suggesting that propene may form viaa carbon-pool mechanism. While all three catalysts deactivate with time on stream, the deactivation of catalysts with Ni(ii) sites on AlOx, i.e., containing surface Ni aluminate sites, is shown to be reversible by calcination (coke removal), in contrast to the deactivation of surface Ni silicate or aluminosilicate sites, which deactivate irreversibly by forming Ni nanoparticles.

The thermal carburization of MoO3nanobelts (nb) and SiO2-supported MoO3nanosheets under a 1 : 4 mixture of CH4 : H2yields Mo2C-nb and Mo2C/SiO2. Following this process by in situMo K-edge X-ray absorption spectroscopy (XAS) reveals different carburization pathways for unsupported and supported MoO3. In particular, the carburization of α-MoO3-nb proceeds viaMoO2, and that of MoO3/SiO2viathe formation of highly dispersed MoOxspecies. Both Mo2C-nb and Mo2C/SiO2catalyze the dry reforming of methane (DRM, 800 °C, 8 bar) but their catalytic stability differs. Mo2C-nb shows a stable performance when using a CH4-rich feed (CH4 : CO2= 4 : 2), however deactivation due to the formation of MoO2occurs for higher CO2concentrations (CH4 : CO2= 4 : 3). In contrast, Mo2C/SiO2is notably more stable than Mo2C-nb under the CH4 : CO2= 4 : 3 feed. The influence of the morphology of Mo2C and its dispersion on silica on the structural evolution of the catalysts under DRM is further studied by in situMo K-edge XAS. It is found that Mo2C/SiO2features a higher resistance to oxidation under DRM than the highly crystalline unsupported Mo2C-nb and this correlates with an improved catalytic stability. Lastly, the oxidation of Mo in both Mo2C-nb and Mo2C/SiO2under DRM conditions in the in situXAS experiments leads to an increased activity of the competing reverse water gas shift reaction.

RNA polymerase I (Pol I) specifically synthesizes ribosomal RNA. Pol I upregulation is linked to cancer, while mutations in the Pol I machinery lead to developmental disorders. Here we report the cryo-EM structure of elongating human Pol I at 2.7 Å resolution. In the exit tunnel, we observe a double-stranded RNA helix that may support Pol I processivity. Our structure confirms that human Pol I consists of 13 subunits with only one subunit forming the Pol I stalk. Additionally, the structure of human Pol I in complex with the initiation factor RRN3 at 3.1 Å resolution reveals stalk flipping upon RRN3 binding. We also observe an inactivated state of human Pol I bound to an open DNA scaffold at 3.3 Å resolution. Lastly, the high-resolution structure of human Pol I allows mapping of disease-related mutations that can aid understanding of disease etiology.

MXenes are two-dimensional materials with a rich set of chemical and electromagnetic properties, the latter including saturable absorption and intense surface plasmon resonances. To fully harness the functionality of MXenes for applications in optics, electronics, and sensing, it is important to understand the interaction of light with MXenes on atomic and femtosecond dimensions. Here, we use ultrafast electron diffraction and high-resolution electron microscopy to investigate the laser-induced structural dynamics of Ti3C2Txnanosheets. We find an exceptionally fast lattice response with an electron-phonon coupling time of 230 fs. Repetitive femtosecond laser excitation transforms Ti3C2Txthrough a structural transition into a metamaterial with deeply sub-wavelength nanoripples that are aligned with the laser polarization. By a further laser illumination, the material is reversibly photo-switchable between a flat and rippled morphology. The resulting nanostructured MXene metamaterial with directional nanoripples is expected to exhibit an anisotropic optical and electronic response as well as an enhanced chemical activity that can be switched on and off by light.

Normen definieren Kriterien für die soziale Akzeptanz und Ablehnung von Kindern in einer Klasse. Welche Normen Grundschulkinder jedoch als relevant für die soziale Akzeptanz bzw. Ablehnung wahrnehmen ist unklar. Dieses Desiderat wurde in einer Interviewstudie (N= 38) und darauf aufbauend in einer Fragebogenstudie (N= 647) adressiert. Die Befunde machen auf die Bedeutung des Sozialverhaltens als wahrgenommene Gruppennorm für die Akzeptanz und Ablehnung aufmerksam, die sich über die Klassenstufen hinweg als stabil erwies. Jahrgangsspezifische Unterschiede fanden sich hingegen für die Bedeutung formeller Normen (z. B. mit Bezug zur Schulleistung), die von Kindern in den höheren Klassenstufen als weniger relevant für den sozialen Status wahrgenommen wurden, als von jenen in den unteren Klassenstufen.

SARS-CoV-2 entry in human cells depends on angiotensin-converting enzyme 2, which can be upregulated by inhibitors of the renin–angiotensin system (RAS). We aimed to test our hypothesis that discontinuation of chronic treatment with ACE-inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) mitigates the course o\f recent-onset COVID-19.

When biogases are directly used as fuels in SOFCs, catalytic reforming of methane into hydrogen and carbon monoxide occurs at the nickel anode. This may expose the anode to localized cooling and a high risk of carbon deposition. These issues can be tackled by preprocessing the biogas. Diluting it with steam or CO2recovered from the SOFC anode off-gas may suppress the risk of carbon deposition whereas reforming it externally can protect the cell from thermal instabilities while offering additional protection against contaminants. Ruthenium has an outstanding catalytic activity with demonstrated coking resistance. Its cost however limits its use. In this work, dry reforming of diluted biogases was performed on a low-ruthenium-exsolution catalyst. An approach by total material balance allowed to determine near 100% methane conversion at GHSV up to 2000 h-1while the reaction was close to the computed thermodynamic equilibrium.

We correlate the catalytic activity for propane dehydrogenation (PDH) of a series of Zn-based Al2O3catalysts with their structure and structural evolution. To this end, three model catalysts are investigated: (i) ZnO/Al2O3prepared by atomic layer deposition (ALD) of ZnO onto γ-Al2O3followed by calcination at 700 °C, which yields a core–shell spinel zinc aluminate/γ-Al2O3; (ii) zinc aluminate spinel nanoparticles (ZnxAlyO4NPs) prepared via a hydrothermal method; and (iii) ZnO/SiO2prepared by ALD of ZnO on SiO2. The catalysts are characterized by synchrotron X-ray powder diffraction (XRD), Zn K-edge X-ray absorption spectroscopy (XAS), and 27Al solid-state nuclear magnetic resonance (ssNMR). We identify tetrahedral Zn sites in close proximity to Al sites of a zinc aluminate spinel phase (ZnIV–O–AlIV/VIlinkages) as more active and selective in PDH relative to the supported ZnO wurtzite phase (ZnIV–O– ZnIVlinkages) in ZnO/SiO2. 50ZnO/Al2O3gives 77% selectivity to propene at 9 mmol C3H6gcat–1h–1space-time yield after 3 min of reaction at 600 °C. The ZnO/Al2O3catalyst shows an irreversible loss of activity over repeated PDH and air-regeneration cycles attributed to Zn depletion on the surface, while the activity loss of ZnxAlyO4NPs due to coke deposition can be recovered by air regeneration.

•The performance of two novel ternary oxides – Ba3Fe2O6 and Ba5Fe2O8 is studied.•Both oxides can cyclically capture CO2at 13.39 wt% and 11.99 wt%, respectively.•Ba3Fe2O6 showed excellent recyclability and satisfactory performance in CLOU.•Strong affinity of Ba5Fe2O8 for CO2renders it unsuitable for use in CLOU.

Nitrification inhibitors are widely used in agriculture to mitigate nitrous oxide (N2O) emission and increase crop yield. However, no concrete information on their mitigation of N2O emission is available under soil and environmental conditions as in Pakistan. A field experiment was established using a silt clay loam soil from Peshawar, Pakistan, to study the effect of urea applied in combination with a nitrification inhibitor, nitrapyrin (2-chloro-6-tri-chloromethyl pyridine), and/or a plant growth regulator, gibberellic acid (GA3), on N2O emission and the nitrogen (N) uptake efficiency of maize. The experimental design was a randomized complete block with five treatments in four replicates: control with no N (CK), urea (200 kg N ha–1) alone, urea in combination with nitrapyrin (700 g ha–1), urea in combination with GA3(60 g ha–1), and urea in combination with nitrapyrin and GA3. The N2O emission, yield, N response efficiency, and total N uptake were measured during the experimental period. The treatment with urea and nitrapyrin reduced total N2O emission by 39%–43% and decreased yield-scaled N2O emission by 47%–52%, relative to the treatment with urea alone. The maize plant biomass, grain yield, and total N uptake increased significantly by 23%, 17%, and 15%, respectively, in the treatment with urea and nitrapyrin, relative to the treatment with urea alone, which was possibly due to N saving, lower N loss, and increased N uptake in the form of ammonium; they were further enhanced in the treatment with urea, nitrapyrin, and GA3by 27%, 36%, and 25%, respectively, probably because of the stimulating effect of GA3on plant growth and development and the reduction in biotic and abiotic stresses. These results suggest that applying urea in combination with nitrapyrin and GA3has the potential to mitigate N2O emission, improve N response efficiency, and increase maize yield.

Urea is the most common nitrogen (N) fertilizer used in the tropics but it has the risk of high gaseous nitrogen (N) losses. Use of nitrification inhibitor has been suggested as a potential mitigation measure for gaseous N losses in N fertilizer-applied fields. In a field trial on a tropical Andosol pastureland in Costa Rica, gaseous emissions of ammonia (NH3) and nitrous oxide (N2O) and grass yield were quantified from plots treated with urea (U; 41.7 kg N ha–1application–1) and urea plus the nitrification inhibitor nitrapyrin (U + NI; 41.7 kg N ha–1application–1and 350 g of nitrapyrin for each 100 kg of N applied) and control plots (without U and NI) over a six-month period (rainy season). Volatilization of NH3(August to November) in U (7.4% ± 1.3% of N applied) and U + NI (8.1% ± 0.9% of N applied) were not significantly different (P >0.05). Emissions of N2O in U and U + NI from June to November were significantly different (P< 0.05) only in October, when N2O emission in U + NI was higher than that in U. Yield and crude protein production of grass were significantly higher (P< 0.05) in U and U + NI than in the control plots, but they were not significantly different between U and U + NI. There was no significant difference in yield-scaled N2O emission between U (0.31 ± 0.10 g N kg–1dry matter) and U + NI (0.47 ± 0.10 g N kg–1dry matter). The results suggest that nitrapyrin is not a viable mitigation option for gaseous N losses under typical N fertilizer application practices of pasturelands at the study site.

In the tropics, frequent nitrogen (N) fertilization of grazing areas can potentially increase nitrous oxide (N2O) emissions. The application of nitrification inhibitors has been reported as an effective management practice for potentially reducing N loss from the soil-plant system and improving N use efficiency (NUE). The aim of this study was to determine the effect of the co-application of nitrapyrin (a nitrification inhibitor, NI) and urea in a tropical Andosol on the behavior of N and the emissions of N2O from autotrophic and heterotrophic nitrification. A greenhouse experiment was performed using a soil (pH 5.9, organic matter content 78 g kg–1, and N 5.6 g kg–1) sown with Cynodon nlemfuensisat 60% water-filled pore space to quantify total N2O emissions, N2O derived from fertilizer, soil ammonium (NH4+) and nitrate (NO3–), and NUE. The study included treatments that received deionized water only (control, CK) and two doses of 15N-enriched urea (65 (UR) and 129 mg N kg–1(UD)) without or with 350 g nitrapyrin for each 100 kg N (UR + NI and UD + NI). No significant differences were observed in soil NH+ content between the UR and UR + NI treatments, probably because of soil mineralization and immobilization (influenced by high soil organic matter content). Nitrapyrin application failed to maintain a stable pool of labeled NO3−due to the additional NO−produced by heterotrophic nitrification, which is not effectively inhibited by nitrapyrin. After 56 d, N2O emissions in UR (0.51 ± 0.12 mg N2O-N kg–1) and UR + NI (0.45 ± 0.13 mg N2O-N kg–1) were not significantly different; by contrast, emissions were 36.3% lower in UD + NI than in UD. It was concluded that the soil organic N mineralization and heterotrophic nitrification are the main processes of NH4+and NO3–production. Additionally, it was found that N2O emissions were partially a consequence of the direct oxidation of the soil's organic N viaheterotrophic nitrification coupled to denitrification. Finally, the results suggest that nitrapyrin would likely exert significant mitigation on N2O emissions only if a substantial N surplus exists in soils with high organic matter content.

This paper focuses on the experimental demonstration of a three-stage GST (gas switching technology) process (fuel, steam/CO2, and air stages) for syngas production from methane in the fuel stage and H2/CO production in the steam/CO2stage using a lanthanum-based oxygen carrier (La0.85Sr0.15Fe0.95Al0.05O3). Experiments were performed at temperatures between 750–950 °C and pressures up to 5 bar. The results show that the oxygen carrier exhibits high selectivity to oxidizing methane to syngas at the fuel stage with improved process performance with increasing temperature although carbon deposition could not be avoided. Co-feeding CO2with CH4at the fuel stage reduced carbon deposition significantly, thus reducing the syngas H2/CO molar ratio from 3.75 to 1 (at CO2/CH4ratio of 1 at 950 °C and 1 bar). The reduced carbon deposition has maximized the purity of the H2produced in the consecutive steam stage thus increasing the process attractiveness for the combined production of syngas and pure hydrogen. Interestingly, the cofeeding of CO2with CH4at the fuel stage showed a stable syngas production over 12 hours continuously and maintained the H2/CO ratio at almost unity, suggesting that the oxygen carrier was exposed to simultaneous partial oxidation of CH4with the lattice oxygen which was restored instantly by the incoming CO2. Furthermore, the addition of steam to the fuel stage could tune up the H2/CO ratio beyond 3 without carbon deposition at H2O/CH4ratio of 1 at 950 °C and 1 bar; making the syngas from gas switching partial oxidation suitable for different downstream processes, for example, gas-to-liquid processes. The process was also demonstrated at higher pressures with over 70% fuel conversion achieved at 5 bar and 950 °C.

Renewable energy resources, which depend on climate, may be susceptible to future climate change. Here we use climate and integrated assessment models to estimate this effect on key renewables. Future potential and costs are quantified across two warming scenarios for eight technologies: utility-scale and rooftop photovoltaic, concentrated solar power, onshore and offshore wind energy, first-generation and lignocellulosic bioenergy, and hydropower. The generated cost–supply curves are then used to estimate energy system impacts. In a baseline warming scenario, the largest impact is increased availability of bioenergy, though this depends on the strength of CO2fertilization. Impacts on hydropower and wind energy are uncertain, with declines in some regions and increases in others, and impacts on solar power are minor. In a future mitigation scenario, these impacts are smaller, but the energy system response is similar to that in the baseline scenario given a larger reliance of the mitigation scenario on renewables.

The development of stable Ni-based dry reforming of methane (DRM) catalysts is a key challenge owing to the high operating temperatures of the process and the propensity of Ni for promoting carbon deposition. In this work, Al2O3-coated Ni/SiO2catalysts have been developed by employing atomic layer deposition (ALD). The structure of the catalyst at each individual preparation step was characterized in detail through a combination of in situXAS–XRD, ex situ27Al NMR and Raman spectroscopy. Specifically, in the calcination step, the ALD-grown Al2O3layer reacts with the SiO2support and Ni, forming aluminosilicate and NiAl2O4. The Al2O3-coated Ni/SiO2catalyst exhibits an improved stability for DRM when compared to the benchmark Ni/SiO2and Ni/Al2O3catalysts. In situXAS–XRD during DRM together with ex situRaman spectroscopy and TEM of the spent catalysts confirm that the ALD-grown Al2O3layer suppresses the sintering of Ni, in turn reducing also coke formation significantly. In addition, the formation of an amorphous aluminosilicate phase by the reaction of the ALD-grown Al2O3layer with the SiO2support inhibited catalysts deactivation viaNiAl2O4formation, in contrast to the reference Ni/Al2O3system. The in-depth structural characterization of the catalysts provided an insight into the structural dynamics of the ALD-grown Al2O3layer, which reacts both with the support and the active metal, allowing to rationalize the high stability of the catalyst under the harsh DRM conditions.

Engineered nanoparticles (NPs) that are released into wastewater are retained by wastewater treatment plants (WWTPs) and accumulate in sewage sludge. Increasing shares of sludge are incinerated and landfilled, especially in industrialized countries. It is debated whether certain types of NPs can outlive the incineration process and subsequently be released from sewage sludge ash (SSA) landfills. To investigate the release of different types of NPs from SSA, we spiked gold (Au), silver (Ag) and cerium dioxide (CeO2) NPs to a pilot WWTP increasing the Au, Ag and Ce concentrations to 30, 43 and 389 mg kg−1(dry matter basis) in the digested sludge. The spiked sludge was incinerated in a pilot fluidized bed reactor resulting in SSA with Au, Ag and Ce concentrations of 61, 103 and 854 mg kg−1. In addition, two sludge samples from a full-scale WWTP with Au concentrations of 5 and 16 mg kg−1were incinerated, resulting in SSA with 9 mg kg−1and 30 mg kg−1Au. The spiked Au-NPs remain largely unaltered during the wastewater treatment and incineration process, whereas Ag-NPs and CeO2-NPs undergo transformation. During simulated landfill leaching in columns flushed with 400 to 500 pore volumes of artificial rainwater, Ag and Ce were retained in the ash, whereas about 17% of the spiked Au was released, mainly in particulate form. Lower fractions of mostly particulate Au were released from the ashes (3 and 9%) of unspiked SSA. In conclusion, unaltered Au-NPs significantly leach from landfilled SSA, whereas the incorporation of Ag-NPs and CeO2-NPs as transformed species into the SSA matrix limits the leaching of (nano)particulate and dissolved Ag and Ce compounds.

In order to gain a better insight into pesticide and pollutant exposure in forests, a rapid and sensitive gas chromatography-tandem mass spectrometry (GC-MS/MS) method for the determination of 208 pesticide residues in leaves and needles has been established. The modified QuEChERS (quick, easy, cheap, effective, rugged and safe) approach uses 2 g of homogenized sample, acetonitrile and water as extraction agents, combined with citrate buffer for the following salting out step. The limits of quantification (LOQs) were determined to 0.0025–0.05 mg kg−1, respectively. Calibration curves showed a linear range between the respective LOQ and 1.0 mg kg−1with coefficients of determination (R2) ≥ 0.99 for all analyzed pesticides. The recovery rates ranged from 69.7% to 92.0% with a relative standard deviation below 20%. The analysis of beech leaves, spruce and pine needles (each n= 3) provided a proof of concept for the developed methodology and revealed the presence of six pesticide residues (boscalid, epoxiconazole, fenpropimorph, lindane, terbuthylazine, terbuthylazine-desethyl). The results underline the strong need for systematic surveillance of the uncontrollable exposure of pesticides to nature.

RNA polymerase III (Pol III) synthesizes transfer RNAs and other short, essential RNAs. Human Pol III misregulation is linked to tumor transformation, neurodegenerative and developmental disorders, and increased sensitivity to viral infections. Here, we present cryo-electron microscopy structures at 2.8 to 3.3 Å resolution of transcribing and unbound human Pol III. We observe insertion of the TFIIS-like subunit RPC10 into the polymerase funnel, providing insights into how RPC10 triggers transcription termination. Our structures resolve elements absent from Saccharomyces cerevisiaePol III such as the winged-helix domains of RPC5 and an iron–sulfur cluster, which tethers the heterotrimer subcomplex to the core. The cancer-associated RPC7α isoform binds the polymerase clamp, potentially interfering with Pol III inhibition by tumor suppressor MAF1, which may explain why overexpressed RPC7α enhances tumor transformation. Finally, the human Pol III structure allows mapping of disease-related mutations and may contribute to the development of inhibitors that selectively target Pol III for therapeutic interventions.

The reductive exsolution of metallic Ru from fluorite-type solid solutions Ln2Ru0.2Ce1.8O7(Ln = Sm, Nd, La) leads to materials with metal–support interactions that influence the electronic state and the catalytic activity of Ru. In situ X-ray absorption spectroscopy at the Ru K-edge identified that with increasing temperature, the exsolution of Ru from Sm2Ru0.2Ce1.8O7in a H2atmosphere proceeds via an intermediate Ruδ+state, that is, Ru4+→Ruδ+→Ru0. X-ray photoelectron spectroscopy (XPS) established that, in parallel (H2atmosphere at ca. 500 °C), also Ce4+ions reduce to Ce3+, which is accompanied by an electron transfer from the reduced host oxide to the exsolved Ru0clusters, creating Ruδ−states. Low-temperature diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) using CO as a probe molecule reveals a red shift of the CO adsorption bands by ca. 18 cm–1when increasing the temperature during the H2treatment from 300 to 500 °C, consistent with an increased π-backdonation from more electron-rich Ru species to CO. However, at a lower reduction temperature of ca. 100 °C, a blue-shifted CO band is observed that is explained by a Lewis-acidic Ruδ+–CO adduct. Nuclear magnetic resonance (NMR) signal enhancement in parahydrogen-induced polarization experiments was used as a structure-sensitive probe and revealed a decreasing propene hydrogenation rate with increasing exsolution temperature, accompanied by a notable enhancement of propane hyperpolarization (ca. 3-fold higher at 500 °C than at 300 °C). These data suggest that the exsolved, subnanometer-sized Ru species are more active in propene hydrogenation but less selective for the pairwise addition of p-H2to propene than Ruδ−sites engaged in a strong metal–support interaction.

Nuclear pore complexes (NPCs) fuse the inner and outer membranes of the nuclear envelope. They comprise hundreds of nucleoporins (Nups) that assemble into multiple subcomplexes and form large central channels for nucleocytoplasmic exchange1,2. How this architecture facilitates messenger RNA export, NPC biogenesis and turnover remains poorly understood. Here we combine in situ structural biology and integrative modelling with correlative light and electron microscopy and molecular perturbation to structurally analyse NPCs in intact Saccharomyces cerevisiaecells within the context of nuclear envelope remodelling. We find an in situ conformation and configuration of the Nup subcomplexes that was unexpected from the results of previous in vitro analyses. The configuration of the Nup159 complex appears critical to spatially accommodate its function as an mRNA export platform, and as a mediator of NPC turnover. The omega-shaped nuclear envelope herniae that accumulate in nup116Δcells3conceal partially assembled NPCs lacking multiple subcomplexes, including the Nup159 complex. Under conditions of starvation, herniae of a second type are formed that cytoplasmically expose NPCs. These results point to a model of NPC turnover in which NPC-containing vesicles bud off from the nuclear envelope before degradation by the autophagy machinery. Our study emphasizes the importance of investigating the structure–function relationship of macromolecular complexes in their cellular context.

Metastable γ-Ga2O3nanocrystals have gained growing interest for a broad range of technological applications. However, a precise description of their atomic structure and changes thereof during thermally induced transformations that is required to understand and fully exploit their physical and chemical properties is still lacking. In this work, we investigate the structure of γ-Ga2O3nanocrystals (2.5 nm in diameter) obtained via a colloidal synthesis route and their evolution with thermal treatment. To this end, we have applied synchrotron X-ray atomic pair distribution function (PDF) analysis, complemented by 71Ga solid-state magic-angle spinning nuclear magnetic resonance (MAS NMR), X-ray absorption spectroscopy (XAS), and electron microscopy. The local structure of the γ-Ga2O3nanocrystals deviates from the average cubic spinel-type structure, revealing a high degree of structural disorder. The average structure of the γ-Ga2O3nanocrystals is described as a defective spinel with gallium sites in tetrahedral and octahedral (GaIVand GaVI) coordination with oxygen atoms. The modeling of the local structure revealed a low-symmetry distortion of the polyhedra, which are disorderly oriented. The surface structure of the γ-Ga2O3nanocrystals is different from their bulk, whereby GaVIsites at the outermost layers of the nanocrystals are found in a nonperiodical stacking arrangement with a higher occupancy than in the core, as revealed by high-angle annular dark field imaging scanning transmission electron microscopy (HAADF-STEM). The structural evolution of γ-Ga2O3nanocrystals upon thermal treatment in air was probed by in situ time-resolved PDF. A gradual transformation of the γ-Ga2O3nanocrystals toward the thermodynamically stable β-Ga2O3polymorph occurs at different structural domains at different temperatures. At ca. 300 °C, changes in the local structure showed an increased distortion of the polyhedral units and revealed the appearance of small β-Ga2O3domains (ca. <1 nm), while the bulk phase transformation took place between 550 and 750 °C and was associated with an increase in the coherence length of the β-Ga2O3phase.

The article presents tips for conducting ensemble lessons online. Suggestions given here for online classes for ensemble teaching include reorganizing the timetable, completing the address and phone list of the students for quick access in the computer, and maintaining the teaching materials in PDF format.

Ruthenium pyrochlores, that is, oxides of composition A2Ru2O7−δ, have emerged recently as state-of-the-art catalysts for the oxygen evolution reaction (OER) in acidic conditions. Here, we demonstrate that the A-site substituent in yttrium ruthenium pyrochlores Y1.8M0.2Ru2O7−δ(M = Cu, Co, Ni, Fe, Y) controls the concentration of surface oxygen vacancies (VO) in these materials whereby an increased concentration of VOsites correlates with a superior OER activity. DFT calculations rationalize these experimental trends demonstrating that the higher OER activity and VOsurface density originate from a weakened strength of the M–O bond, scaling with the formation enthalpy of the respective MOxphases and the coupling between the M dstates and O 2pstates. Our work introduces a novel catalyst with improved OER performance, Y1.8Cu0.2Ru2O7−δ, and provides general guidelines for the design of active electrocatalysts.