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Plant embryos are generated and develop in a stable and well-protected microenvironment surrounded by maternal tissue, which is vital for embryogenesis. However, the signaling mechanisms responsible for maternal tissue-to-proembryo communication are not well understood. Here, we report a pathway for maternal tissue-to-proembryo communication. We identify a DELLA protein, NtCRF1 (NtCYS regulative factor 1), which regulates suspensor programmed cell death (PCD). NtCRF1 can bind to the promoter of NtCYS and regulate the suspensor PCD-switch module NtCYS-NtCP14 in response to gibberellin (GA). We confirm that GA4, as a primary signal triggering suspensor PCD, is generated in the micropylar endothelium by the transient activation of NtGA3oxs in the maternal tissue. Thus, we propose that GA is a maternal-to-proembryo communication signal that is decoded in the proembryo by a GID1-CRF1-CYS-CP14 signaling cascade. Using this mode of communication, maternal tissue precisely controls the embryonic suspensor PCD and is able to nurse the proembryo in a stage-dependent manner., Plant embryos are connected to maternal tissue by a filamentous suspensor, analogous to an umbilical cord, but which is severed during early embryo development. Here, Shi et al. show that gibberellins can trigger suspensor cell death in tobacco via a DELLA protein that regulates expression of cell death factors.

Solar-driven hydrogen production from water using particulate photocatalysts is considered the most economical and effective approach to produce hydrogen fuel with little environmental concern. However, the efficiency of hydrogen production from water in particulate photocatalysis systems is still low. Here, we propose an efficient biphase photocatalytic system composed of integrated photothermal–photocatalytic materials that use charred wood substrates to convert liquid water to water steam, simultaneously splitting hydrogen under light illumination without additional energy. The photothermal–photocatalytic system exhibits biphase interfaces of photothermally-generated steam/photocatalyst/hydrogen, which significantly reduce the interface barrier and drastically lower the transport resistance of the hydrogen gas by nearly two orders of magnitude. In this work, an impressive hydrogen production rate up to 220.74 μmol h−1 cm−2 in the particulate photocatalytic systems has been achieved based on the wood/CoO system, demonstrating that the photothermal–photocatalytic biphase system is cost-effective and greatly advantageous for practical applications., The solar-driven H2 production from water by particulate photocatalysts is an effective approach to produce H2 fuel. Here, the authors propose an integrated photothermal–photocatalytic biphase system, which lowers the reaction barrier and the delivery resistance of the H2, boosting the catalytic H2 evolution rate.

Magnesium, the lightest structural metal, usually exhibits limited ambient plasticity when compressed along its crystallographic c-axis (the “hard” orientation of magnesium). Here we report large plasticity in c-axis compression of submicron magnesium single crystal achieved by a dual-stage deformation. We show that when the plastic flow gradually strain-hardens the magnesium crystal to gigapascal level, at which point dislocation mediated plasticity is nearly exhausted, the sample instantly pancakes without fracture, accompanying a conversion of the initial single crystal into multiple grains that roughly share a common rotation axis. Atomic-scale characterization, crystallographic analyses and molecular dynamics simulations indicate that the new grains can form via transformation of pyramidal to basal planes. We categorize this grain formation as “deformation graining”. The formation of new grains rejuvenates massive dislocation slip and deformation twinning to enable large plastic strains.

Capture and storage of volatile radionuclides that result from processing of used nuclear fuel is a major challenge. Solid adsorbents, in particular ultra-microporous metal-organic frameworks, could be effective in capturing these volatile radionuclides, including 85Kr. However, metal-organic frameworks are found to have higher affinity for xenon than for krypton, and have comparable affinity for Kr and N2. Also, the adsorbent needs to have high radiation stability. To address these challenges, here we evaluate a series of ultra-microporous metal-organic frameworks, SIFSIX-3-M (M = Zn, Cu, Ni, Co, or Fe) for their capability in 85Kr separation and storage using a two-bed breakthrough method. These materials were found to have higher Kr/N2 selectivity than current benchmark materials, which leads to a notable decrease in the nuclear waste volume. The materials were systematically studied for gamma and beta irradiation stability, and SIFSIX-3-Cu is found to be the most radiation resistant., Management of spent nuclear fuel is challenging due to the release of volatile radionuclides. Here the authors report krypton separation from fission gas in the presence of other competing gases by a radiation resistant metal-organic framework using the two-bed breakthrough technique.

The C-type lectin member 5A (CLEC5A) is a pattern recognition receptor for members of the Flavivirus family and has critical functions in response to dengue virus and Japanese encephalitis virus. Here we show that CLEC5A is involved in neutrophil extracellular trap formation and the production of reactive oxygen species and proinflammatory cytokines in response to Listeria monocytogenes. Inoculation of Clec5a −/− mice with L. monocytogenes causes rapid bacterial spreading, increased bacterial loads in the blood and liver, and severe liver necrosis. In these mice, IL-1β, IL-17A, and TNF expression is inhibited, CCL2 is induced, and large numbers of CD11b+Ly6ChiCCR2hiCX3CR1low inflammatory monocytes infiltrate the liver. By day 5 of infection, these mice also have fewer IL-17A+ γδ T cells, severe liver necrosis and a higher chance of fatality. Thus, CLEC5A has a pivotal function in the activation of multiple aspects of innate immunity against bacterial invasion., The lectin receptor CLEC5A is a pattern recognition receptor that has been shown to detect dengue and Japanese encephalitis virus. Here the authors show that CLEC5A is needed for optimal ROS production, NET formation and other immune responses to Listeria monocytogenes in mice.

The structure of the cornea is vital to its transparency, and dystrophies that disrupt corneal organization are highly heritable. To understand the genetic aetiology of Fuchs endothelial corneal dystrophy (FECD), the most prevalent corneal disorder requiring transplantation, we conducted a genome-wide association study (GWAS) on 1,404 FECD cases and 2,564 controls of European ancestry, followed by replication and meta-analysis, for a total of 2,075 cases and 3,342 controls. We identify three novel loci meeting genome-wide significance (P, Fuchs endothelial corneal dystrophy (FECD) is one of the most common reasons for corneal transplantation, and is known to cluster in families. Here, the authors discover new genetic loci associated with FECD with sex-specific effects and implications for disease mechanism.

Due to its high diffusivity, hydrogen is often considered a weak inhibitor or even a promoter of dislocation movements in metals and alloys. By quantitative mechanical tests in an environmental transmission electron microscope, here we demonstrate that after exposing aluminium to hydrogen, mobile dislocations can lose mobility, with activating stress more than doubled. On degassing, the locked dislocations can be reactivated under cyclic loading to move in a stick-slip manner. However, relocking the dislocations thereafter requires a surprisingly long waiting time of ∼103 s, much longer than that expected from hydrogen interstitial diffusion. Both the observed slow relocking and strong locking strength can be attributed to superabundant hydrogenated vacancies, verified by our atomistic calculations. Vacancies therefore could be a key plastic flow localization agent as well as damage agent in hydrogen environment., Due to its high diffusivity, hydrogen is considered a weak inhibitor or even a promoter of dislocation movements in metals and alloys. Here the authors quantitatively demonstrate that after exposing aluminium to hydrogen, mobile dislocations can lose mobility, due to segregation of hydrogenated vacancies to dislocations.

The removal of highly toxic, ultra-dilute contaminants of concern has been a primary challenge for clean water technologies. Chromium and arsenic are among the most prevalent heavy metal pollutants in urban and agricultural waters, with current separation processes having severe limitations due to lack of molecular selectivity. Here, we report redox-active metallopolymer electrodes for the selective electrochemical removal of chromium and arsenic. An uptake greater than 100 mg Cr/g adsorbent can be achieved electrochemically, with a 99% reversible working capacity, with the bound chromium ions released in the less harmful trivalent form. Furthermore, we study the metallopolymer response during electrochemical modulation by in situ transmission electron microscopy. The underlying mechanisms for molecular selectivity are investigated through electronic structure calculations, indicating a strong charge transfer to the heavy metal oxyanions. Finally, chromium and arsenic are remediated efficiently at concentrations as low as 100 ppb, in the presence of over 200-fold excess competing salts., Chromium and arsenic are prevalent water pollutants, but their removal is currently limited by low selectivity. Here, the authors use redox-active metallopolymer electrodes based on poly(vinyl)ferrocene to selectively remove the two heavy metal oxyanions at concentrations as low as 100 ppb.

Despite their energy-efficient merits as promising light-weight structural materials, magnesium (Mg) based alloys suffer from inadequate corrosion resistance. One primary reason is that the native surface film on Mg formed in air mainly consists of Mg(OH)2 and MgO, which is porous and unprotective, especially in humid environments. Here, we demonstrate an environmentally benign method to grow a protective film on the surface of Mg/Mg alloy samples at room temperature, via a direct reaction of already-existing surface film with excited CO2. Moreover, for samples that have been corroded obviously on surface, the corrosion products can be converted directly to create a new protective surface. Mechanical tests show that compared with untreated samples, the protective layer can elevate the yield stress, suppress plastic instability and prolong compressive strains without peeling off from the metal surface. This environmentally friendly surface treatment method is promising to protect Mg alloys, including those already-corroded on the surface.

Despite their energy-efficient merits as promising light-weight structural materials, magnesium (Mg) based alloys suffer from inadequate corrosion resistance. One primary reason is that the native surface film on Mg formed in air mainly consists of Mg(OH)2 and MgO, which is porous and unprotective, especially in humid environments. Here, we demonstrate an environmentally benign method to grow a protective film on the surface of Mg/Mg alloy samples at room temperature, via a direct reaction of already-existing surface film with excited CO2. Moreover, for samples that have been corroded obviously on surface, the corrosion products can be converted directly to create a new protective surface. Mechanical tests show that compared with untreated samples, the protective layer can elevate the yield stress, suppress plastic instability and prolong compressive strains without peeling off from the metal surface. This environmentally friendly surface treatment method is promising to protect Mg alloys, including those already-corroded on the surface., Magnesium alloys usually have poor corrosion resistance, which inhibits their use in the automotive and biomedical industries. Here, the authors use an environmental TEM to carbonate the natural corrosion products at the surface of magnesium alloys and form a compact and protective surface layer.

Lithium titanate and titanium dioxide are two best-known high-performance electrodes that can cycle around 10,000 times in aprotic lithium ion electrolytes. Here we show there exists more lithium titanate hydrates with superfast and stable cycling. That is, water promotes structural diversity and nanostructuring of compounds, but does not necessarily degrade electrochemical cycling stability or performance in aprotic electrolytes. As a lithium ion battery anode, our multi-phase lithium titanate hydrates show a specific capacity of about 130 mA h g−1 at ~35 C (fully charged within ~100 s) and sustain more than 10,000 cycles with capacity fade of only 0.001% per cycle. In situ synchrotron diffraction reveals no 2-phase transformations, but a single solid-solution behavior during battery cycling. So instead of just a nanostructured intermediate to be calcined, lithium titanate hydrates can be the desirable final destination., Water is usually not favorable in high-voltage window aprotic electrolytes. Here the authors discover some lithium titanate hydrates that allow superior power rate and ultralong cycle life in aprotic electrolytes.

Corrigendum: Optoelectronic crystal of artificial atoms in strain-textured molybdenum disulphide

Alloy-type anodes such as silicon and tin are gaining popularity in rechargeable Li-ion batteries, but their rate/cycling capabilities should be improved. Here by making yolk-shell nanocomposite of aluminium core (30 nm in diameter) and TiO[subscript 2] shell (~3 nm in thickness), with a tunable interspace, we achieve 10 C charge/discharge rate with reversible capacity exceeding 650 mAh g[superscript −1] after 500 cycles, with a 3 mg cm[superscript −2] loading. At 1 C, the capacity is approximately 1,200 mAh g[superscript −1] after 500 cycles. Our one-pot synthesis route is simple and industrially scalable. This result may reverse the lagging status of aluminium among high-theoretical-capacity anodes., National Science Foundation (U.S.) (Grant DMR-1120901), National Natural Science Foundation (China) (51221291), National Natural Science Foundation (China) (51172119)

The isolation of the two-dimensional semiconductor molybdenum disulphide introduced a new optically active material possessing a band gap that can be facilely tuned via elastic strain. As an atomically thin membrane with exceptional strength, monolayer molybdenum disulphide subjected to biaxial strain can embed wide band gap variations overlapping the visible light spectrum, with calculations showing the modified electronic potential emanating from point-induced tensile strain perturbations mimics the Coulomb potential in a mesoscopic atom. Here we realize and confirm this ‘artificial atom’ concept via capillary-pressure-induced nanoindentation of monolayer molybdenum disulphide from a tailored nanopattern, and demonstrate that a synthetic superlattice of these building blocks forms an optoelectronic crystal capable of broadband light absorption and efficient funnelling of photogenerated excitons to points of maximum strain at the artificial-atom nuclei. Such two-dimensional semiconductors with spatially textured band gaps represent a new class of materials, which may find applications in next-generation optoelectronics or photovoltaics., Samsung Advanced Institute of Technology (2013 Global Research Outreach Program Award IC2012-1318), National Science Foundation (U.S.) (CBET-1240696), National Science Foundation (U.S.) (DMR-1120901)

Alloy-type anodes such as silicon and tin are gaining popularity in rechargeable Li-ion batteries, but their rate/cycling capabilities should be improved. Here by making yolk-shell nanocomposite of aluminium core (30 nm in diameter) and TiO2 shell (∼3 nm in thickness), with a tunable interspace, we achieve 10 C charge/discharge rate with reversible capacity exceeding 650 mAh g−1 after 500 cycles, with a 3 mg cm−2 loading. At 1 C, the capacity is approximately 1,200 mAh g−1 after 500 cycles. Our one-pot synthesis route is simple and industrially scalable. This result may reverse the lagging status of aluminium among high-theoretical-capacity anodes., Aluminium offers an attractive alternative anode for lithium-ion batteries, but its practical performance falls far short of the theoretical promise. Here, the authors present a yolk-shell structured nanocomposite anode of aluminium core and titanium oxide shell which displays outstanding electrochemical properties.

The regenerative capacity of skeletal muscle declines with age. Previous studies suggest that this process can be reversed by exposure to young circulation; however, systemic age-specific factors responsible for this phenomenon are largely unknown. Here we report that oxytocin--a hormone best known for its role in lactation, parturition and social behaviours--is required for proper muscle tissue regeneration and homeostasis, and that plasma levels of oxytocin decline with age. Inhibition of oxytocin signalling in young animals reduces muscle regeneration, whereas systemic administration of oxytocin rapidly improves muscle regeneration by enhancing aged muscle stem cell activation/proliferation through activation of the MAPK/ERK signalling pathway. We further show that the genetic lack of oxytocin does not cause a developmental defect in muscle but instead leads to premature sarcopenia. Considering that oxytocin is an FDA-approved drug, this work reveals a potential novel and safe way to combat or prevent skeletal muscle ageing.