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Thin (approximately 10 nm) oxide buffer layers grown over lead-halide perovskite device stacks are critical for protecting the perovskite against mechanical and environmental damage. However, the limited perovskite stability restricts the processing methods and temperatures (=180 ��C to be used to coat the perovskite. This is >=70 ��C higher than achievable by current methods and results in more conductive TiOx films, boosting solar cell efficiencies by >2%. Likewise, when AP-CVD SnOx (x ~ 2) is grown on perovskites, there is also minimal damage to the perovskite beneath. The SnOx layer is pinhole-free and conformal, which reduces shunting in devices, and increases steady-state efficiencies from 16.5% (no SnOx) to 19.4% (60 nm SnOx), with fill factors reaching 84%. This work shows AP-CVD to be a versatile technique for growing oxides on thermally-sensitive materials., R.D.R and R.A.J contributed equally. 23 pages. 6 figures

The fundamental limits currently faced by traditional computing devices necessitate the exploration of ways to store, compute, and transmit information going beyond the current CMOS-based technologies. Here, we propose a three-dimensional (3D) magnetic interconnector that exploits geometry-driven automotion of domain walls (DWs), for the transfer of magnetic information between functional magnetic planes. By combining state-of-the-art 3D nanoprinting and standard physical vapor deposition, we prototype 3D helical DW conduits. We observe the automotion of DWs by imaging their magnetic state under different field sequences using X-ray microscopy, observing a robust unidirectional motion of DWs from the bottom to the top of the spirals. From experiments and micromagnetic simulations, we determine that the large thickness gradients present in the structure are the main mechanism for 3D DW automotion. We obtain direct evidence of how this tailorable magnetic energy gradient is imprinted in the devices, and how it competes with pinning effects that are due to local changes in the energy landscape. Our work also predicts how this effect could lead to high DW velocities, reaching the Walker limit during automotion. This work demonstrates a possible mechanism for efficient transfer of magnetic information in three dimensions., This work was supported by the EPSRC Cambridge NanoDTC EP/L015978/1, the Winton Program for the Physics of Sustainability, the project CALIPSOplus (under Grant Agreement No. 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020), and by the European Community (under the Horizon 2020 Program, Contract No. 101001290, 3DNANOMAG). L.S. acknowledges support from St. Johns College of the University of Cambridge. C.D. was supported by the Leverhulme Trust (No. ECF-2018-016), the Isaac Newton Trust (No. 18-08), and the L’Oréal-UNESCO UK and Ireland Fellowship For Women In Science. A.H.-R. acknowledges support from Spanish AEI, under Project Reference No. PID2019-104604RB/AEI/10.13039/501100011033. The authors acknowledge the University of Vienna research platform MMM Mathematics–Magnetism–Materials, the FWF (Project No. I 4917), and Aragon Government through the Project Q-MAD.

International audience; Radiocarbon is an extremely useful carbon cycle tracer and radiometric dating tool. Here, we review the main principles and challenges involved in the use of radiocarbon in paleoceanography. First, we present a conceptual framework in which there are three possible uses of a radiocarbon measurement: (a) to obtain a calendar age interval, or a fossil entity's age; (b) to obtain an estimate of a carbon reservoir's past radiocarbon activity; or (c) to compare the relative radiocarbon activities of two contemporary carbon reservoirs. We discuss the analysis of marine fossil material, the generation of an atmospheric reference curve, and the interpretation of marine radiocarbon "ventilation metrics" in relation to this reference curve. It is emphasized that marine radiocarbon integrates the influences of: changing radiocarbon production; air-sea gas exchange effects at the sea surface; transport times within the ocean interior; and the mixing of water parcels with different transit times from the sea surface, and different sea-surface sources. These controls are what make radiocarbon such a powerful paleoceanographic tracer, though the difficulty of disentangling them is what makes marine radiocarbon dating and tracer studies so challenging. We discuss the implementation of radiocarbon in numerical models, and explore the theory linking ocean-atmosphere partitioning of radiocarbon and CO2. Finally, we review existing records of marine radiocarbon variability over the last ∼25,000 years, which highlight the influence of ocean-atmosphere carbon exchange on past atmospheric CO2 and climate, and point to emerging opportunities for resolving the global radiocarbon- and carbon budgets over the last glacial cycle.

Perovskite solar cells (PSCs) with transparent electrodes can be integrated with existing solar panels in tandem configurations to increase the power conversion efficiency. A critical layer in semi-transparent PSCs is the inorganic buffer layer, which protects the PSC against damage when the transparent electrode is sputtered on top. The development of n-i-p structured semi-transparent PSCs has been hampered by the lack of suitable p-type buffer layers. In this work we develop a p-type CuOx buffer layer, which can be grown uniformly over the perovskite device without damaging the perovskite or organic hole transport layer. The CuOx layer has high hole mobility (4.3 ± 2 cm2 V-1 s-1), high transmittance (>95%), and a suitable ionization potential for hole extraction (5.3 ± 0.2 eV). Semi-transparent PSCs with efficiencies up to 16.7% are achieved using the CuOx buffer layer. Our work demonstrates a new approach to integrate n-i-p structured PSCs into tandem configurations, as well as enable the development of other devices that need high quality, protective p-type layers., EPSRC Department Training Partnership studentship (No: EP/N509620/1), as well as Bill Welland. T.N.H. acknowledges funding from the EPSRC Centre for Doctoral Training in Graphene Technology (No. EP/L016087/1) and the Aziz Foundation. W.-W.L. and J.L.M.-D. acknowledge support from the EPSRC (Nos.: EP/L011700/1, EP/N004272/10), and the Isaac Newton Trust (Minute 13.38(k)). M.N. and J.L.M.-D. acknowledge financial support from EPSRC (No. EP/P027032/1). S. D. S. acknowledges support from the Royal Society and Tata Group (UF150033). R.L.Z.H. acknowledges support from the Royal Academy of Engineering under the Research Fellowship scheme (No.: RF\201718\1701), the Centre of Advanced Materials for Integrated Energy Systems (EPSRC Grant No. EP/P007767/1), the Isaac Newton Trust (Minute 19.07(d)), and the Kim and Juliana Silverman Research Fellowship at Downing College, Cambridge.

Funder: Consortium des Équipements de Calcul Intensif, Funder: The Leverhulme Trust, While the charge transport properties of organic semiconductors have been extensively studied over the recent years, the field of organics‐based thermoelectrics is still limited by a lack of experimental data on thermal transport and of understanding of the associated structure–property relationships. To fill this gap, a comprehensive experimental and theoretical investigation of the lattice thermal conductivity in polycrystalline thin films of dinaphtho[2,3‐b:2′,3′‐f]thieno[3,2‐b]thiophene (Cn‐DNTT‐Cn with n = 0, 8) semiconductors is reported. Strikingly, thermal conductivity appears to be much more isotropic than charge transport, which is confined to the 2D molecular layers. A direct comparison between experimental measurements (3ω–Völklein method) and theoretical estimations (approach‐to‐equilibrium molecular dynamics (AEMD) method) indicates that the in‐plane thermal conductivity is strongly reduced in the presence of the long terminal alkyl chains. This evolution can be rationalized by the strong localization of the intermolecular vibrational modes in C8‐DNTT‐C8 in comparison to unsubstituted DNTT cores, as evidenced by a vibrational mode analysis. Combined with the enhanced charge transport properties of alkylated DNTT systems, this opens the possibility to decouple electron and phonon transport in these materials, which provides great potential for enhancing the thermoelectric figure of merit ZT.

International audience; Mutations in OPA1 cause autosomal dominant optic atrophy (DOA) as well as DOA+, a phenotype characterized by more severe neurological deficits. OPA1 deficiency causes mitochondrial fragmentation and also disrupts cristae, respiration, mitochondrial DNA (mtDNA) maintenance, and cell viability. It has not yet been established whether phenotypic severity can be modulated by genetic modifiers of OPA1. We screened the entire known mitochondrial proteome (1,531 genes) to identify genes that control mitochondrial morphology using a first-in-kind imaging pipeline. We identified 145 known and novel candidate genes whose depletion promoted elongation or fragmentation of the mitochondrial network in control fibroblasts and 91 in DOA+ patient fibroblasts that prevented mitochondrial fragmentation, including phosphatidyl glycerophosphate synthase (PGS1). PGS1 depletion reduces CL content in mitochondria and rebalances mitochondrial dynamics in OPA1-deficient fibroblasts by inhibiting mitochondrial fission, which improves defective respiration, but does not rescue mtDNA depletion, cristae dysmorphology, or apoptotic sensitivity. Our data reveal that the multifaceted roles of OPA1 in mitochondria can be functionally uncoupled by modulating mitochondrial lipid metabolism, providing novel insights into the cellular relevance of mitochondrial fragmentation.

The implementation of nano-engineered composite oxides opens up the way towards the development of a novel class of functional materials with enhanced electrochemical properties. Here we report on the realization of vertically aligned nanocomposites of lanthanum strontium manganite and doped ceria with straight applicability as functional layers in high-temperature energy conversion devices. By a detailed analysis using complementary state-of-the-art techniques, which include atom-probe tomography combined with oxygen isotopic exchange, we assess the local structural and electrochemical functionalities and we allow direct observation of local fast oxygen diffusion pathways. The resulting ordered mesostructure, which is characterized by a coherent, dense array of vertical interfaces, shows high electrochemically activity and suppressed dopant segregation. The latter is ascribed to spontaneous cationic intermixing enabling lattice stabilization, according to density functional theory calculations. This work highlights the relevance of local disorder and long-range arrangements for functional oxides nano-engineering and introduces an advanced method for the local analysis of mass transport phenomena., J.S. acknowledges the support of ICN2 (funded by the CERCA programme/Generalitat de Catalunya and by the Severo Ochoa programme SEV-2017-0706) for the XRD measurements. M.A. acknowledges the support from the Feodor Lynen Research Fellowship Program of the Alexander von Humboldt Foundation and the Isaac Newton Trust, 17.25(a). M.A. and J.D. acknowledge the support from the EPSRC Centre of Advanced Materials for Integrated Energy Systems (CAM-IES) under EP/P007767/1. J.D. also acknowledge support from EPSRC grants EP/N004272/1, EP/T012218/1, the Royal Academy of Engineering- CIET1819_24, ERC POC grant 779444, Portapower. X.W. and H.W. acknowledge the funding support from the U.S. National Science Foundation for the TEM effort at Purdue University (DMR-1565822 and DMR-2016453). This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 824072 (HARVESTORE), No 681146 (ULTRASOFC) and No 101017709 (EPISTORE) and was supported by an STSM Grant from the COST Action MP1308: Towards Oxide-Based Electronics (TO-BE), supported by COST (European Cooperation in Science and Technology).

Funder: Aziz Foundation, Funder: Downing College, Cambridge, Funder: Isaac Newton Trust; Id: http://dx.doi.org/10.13039/501100004815, Nickel oxide (NiO x ), a p‐type oxide semiconductor, has gained significant attention due to its versatile and tunable properties. It has become one of the critical materials in wide range of electronics applications, including resistive switching random access memory devices and highly sensitive and selective sensor applications. In addition, the wide band gap and high work function, coupled with the low electron affinity, have made NiO x widely used in emerging optoelectronics and p‐n heterojunctions. The properties of NiO x thin films depend strongly on the deposition method and conditions. Efficient implementation of NiO x in next‐generation devices will require controllable growth and processing methods that can tailor the morphological and electronic properties of the material, but which are also compatible with flexible substrates. In this review, we link together the fundamental properties of NiO x with the chemical processing methods that have been developed to grow the material as thin films, and with its application in electronic devices. We focus solely on thin films, rather than NiO x incorporated with one‐dimensional or two‐dimensional materials. This review starts by discussing how the p‐type nature of NiO x arises and how its stoichiometry affects its electronic and magnetic properties. We discuss the chemical deposition techniques for growing NiO x thin films, including chemical vapor deposition, atomic layer deposition, and a selection of solution processing approaches, and present examples of recent progress made in the implementation of NiO x thin films in devices, both on rigid and flexible substrates. Furthermore, we discuss the remaining challenges and limitations in the deposition of device‐quality NiO x thin films with chemical growth methods. image

The design of complex, competing effects in magnetic systems – be it via the introduction of nonlinear interactions, or the patterning of three-dimensional geometries – is an emerging route to achieve new functionalities. Here, we combine 3D geometric effects with non-linear and non-local interactions to produce magnetic field textures in free space. For this, we harness direct write nanofabrication techniques, creating intertwined nanomagnetic cobalt double helices, where curvature, torsion, chirality, and magnetic coupling are jointly exploited. By reconstructing the 3D vectorial magnetic state of the double helices with soft X-ray magnetic laminography, we identify the presence of a regular array of highly coupled locked domain wall pairs in neighbouring helices. Micromagnetic simulations reveal that the magnetisation configuration leads to the formation of an array of complex textures in the magnetic induction, consisting of vortices in the magnetisation and antivortices in free space, which together, form an effective B-field cross-tie wall. The design and creation of complex three-dimensional magnetic field nanotextures opens new possibilities for smart materials, unconventional computing, particle trapping and magnetic imaging., This work was funded by an EPSRC Early Career Fellowship EP/M008517/1 and the Winton Program for the Physics of Sustainability. C.D. acknowledges funding from the Leverhulme Trust (ECF-2018-016), the Isaac Newton Trust (18-08), the L’Oréal-UNESCO UK and Ireland Fellowship For Women In Science 2019, and the Max Planck Society Lise Meitner Excellence Program. A.F.P. acknowledges funding by the European Community under the Horizon 2020 Program, Contract no. 101001290, 3DNANOMAG. A.H.-R. and S.MV. acknowledge the support from European Union’s Horizon 2020 research and innovation program under Marie Skłodowska-Curie grant ref. H2020-MSCA-IF-2016-746958. A.H.-R. acknowledges funding from Spanish AEI under project reference PID2019–104604RB/AEI/10.13039/501100011033. The PolLux end station was financed by the German Ministerium für Bildung und Forschung (BMBF) through contracts 05K16WED and 05K19WE2. K.W. acknowledges the funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no. 701647. A.F.P. is grateful to the University of Cambridge and the University of Glasgow, where part of this research was performed.

International audience; Endosymbioses have shaped the evolutionary trajectory of life and remain ecologically important. Investigating oceanic photosymbioses can illuminate how algal endosymbionts are energetically exploited by their heterotrophic hosts and inform on putative initial steps of plastid acquisition in eukaryotes. By combining three-dimensional subcellular imaging with photophysiology, carbon flux imaging, and transcriptomics, we show that cell division of endosymbionts ( Phaeocystis ) is blocked within hosts (Acantharia) and that their cellular architecture and bioenergetic machinery are radically altered. Transcriptional evidence indicates that a nutrient-independent mechanism prevents symbiont cell division and decouples nuclear and plastid division. As endosymbiont plastids proliferate, the volume of the photosynthetic machinery volume increases 100-fold in correlation with the expansion of a reticular mitochondrial network in close proximity to plastids. Photosynthetic efficiency tends to increase with cell size, and photon propagation modeling indicates that the networked mitochondrial architecture enhances light capture. This is accompanied by 150-fold higher carbon uptake and up-regulation of genes involved in photosynthesis and carbon fixation, which, in conjunction with a ca.15-fold size increase of pyrenoids demonstrates enhanced primary production in symbiosis. Mass spectrometry imaging revealed major carbon allocation to plastids and transfer to the host cell. As in most photosymbioses, microalgae are contained within a host phagosome (symbiosome), but here, the phagosome invaginates into enlarged microalgal cells, perhaps to optimize metabolic exchange. This observation adds evidence that the algal metamorphosis is irreversible. Hosts, therefore, trigger and benefit from major bioenergetic remodeling of symbiotic microalgae with potential consequences for the oceanic carbon cycle. Unlike other photosymbioses, this interaction represents a so-called cytoklepty, which is a putative initial step toward plastid acquisition.

Funder: Ministry of Education, Taiwan, Lead-halide perovskites have demonstrated astonishing increases in power conversion efficiency in photovoltaics over the last decade. The most efficient perovskite devices now outperform industry-standard multi-crystalline silicon solar cells, despite the fact that perovskites are typically grown at low temperature using simple solution-based methods. However, the toxicity of lead and its ready solubility in water are concerns for widespread implementation. These challenges, alongside the many successes of the perovskites, have motivated significant efforts across multiple disciplines to find lead-free and stable alternatives which could mimic the ability of the perovskites to achieve high performance with low temperature, facile fabrication methods. This Review discusses the computational and experimental approaches that have been taken to discover lead-free perovskite-inspired materials, and the recent successes and challenges in synthesizing these compounds. The atomistic origins of the extraordinary performance exhibited by lead-halide perovskites in photovoltaic devices is discussed, alongside the key challenges in engineering such high-performance in alternative, next-generation materials. Beyond photovoltaics, this Review discusses the impact perovskite-inspired materials have had in spurring efforts to apply new materials in other optoelectronic applications, namely light-emitting diodes, photocatalysts, radiation detectors, thin film transistors and memristors. Finally, the prospects and key challenges faced by the field in advancing the development of perovskite-inspired materials towards realization in commercial devices is discussed.

24 p.-10 fig., The cucumber mosaic virus (CMV) 2b viral suppressor of RNA silencing (VSR) is a potent counter-defense and pathogenicity factor that inhibits antiviral silencing by titration of short double-stranded RNAs. It also disrupts microRNA-mediated regulation of host gene expression by binding ARGONAUTE 1 (AGO1). But in Arabidopsis thaliana complete inhibition of AGO1 is counterproductive to CMV since this triggers another layer of antiviral silencing mediated by AGO2, de-represses strong resistance against aphids (the insect vectors of CMV), and exacerbates symptoms. Using confocal laser scanning microscopy, bimolecular fluorescence complementation, and co-immunoprecipitation assays we found that the CMV 1a protein, a component of the viral replicase complex, regulates the 2b-AGO1 interaction.By binding 2b protein molecules and sequestering them in P-bodies, the 1a protein limits the proportion of 2b protein molecules available to bind AGO1, which ameliorates 2b-induced disease symptoms, and moderates induction of resistance to CMV and to its aphid vector.However, the 1a protein-2b protein interaction does not inhibit the ability of the 2b protein to inhibit silencing of reporter gene expression in agroinfiltration assays. The interaction between the CMV 1a and 2b proteins represents a novel regulatory system in which specific functions of a VSR are selectively modulated by another viral protein. The finding also provides a mechanism that explains how CMV, and possibly other viruses, modulates symptom induction and manipulates host-vector interactions., Major funding for this project was provided to JPC by the UK Biotechnological and Biological Sciences Research Council (Grant numbers BB/J011762/1 and GCRF BB/P023223/1. Additional funding was obtained from the Leverhulme Trust (Grant numbers RPG-2012-667 and F/09741/F: https://www.leverhulme.ac.uk/) to JPC, and Newton Trust (http://www.newtontrust.cam.ac.uk/: grant number 12.07/I) to AMM.

With the exponential rise in the market value and number of devices part of the Internet of Things (IoT), the demand for indoor photovoltaics (IPV) to power autonomous devices is predicted to rapidly increase. Lead‐free perovskite‐inspired materials (PIMs) have recently attracted significant attention in photovoltaics research, due to the similarity of their electronic structure to high‐performance lead‐halide perovskites, but without the same toxicity limitations. However, the capability of PIMs for indoor light harvesting has not yet been considered. Herein, two exemplar PIMs, BiOI and Cs3Sb2ClxI9‐x are examined. It is shown that while their bandgaps are too wide for single‐junction solar cells, they are close to the optimum for indoor light harvesting. As a result, while BiOI and Cs3Sb2ClxI9‐x devices are only circa 1%‐efficient under 1‐sun illumination, their efficiencies increase to 4–5% under indoor illumination. These efficiencies are within the range of reported values for hydrogenated amorphous silicon, i.e., the industry standard for IPV. It is demonstrated that such performance levels are already sufficient for millimeter‐scale PIM devices to power thin‐film‐transistor circuits. Intensity‐dependent and optical loss analyses show that future improvements in efficiency are possible. Furthermore, calculations of the optically limited efficiency of these and other low‐toxicity PIMs reveal their considerable potential for IPV, thus encouraging future efforts for their exploration for powering IoT devices.

In methylammonium lead iodide (MAPbI3) perovskite solar cells (PSCs), the device performance is strongly influenced by the TiO2 elec-tron transport layer (ETL). Typically, the ETL needs to simultaneously be thin and pinhole-free in order to have high transmittance and avoid shunting. In this work, we develop an “in-situ solidification” process following spin coating, in which the titanium-based precursor (ti-tanium (diisopropoxide) bis (2,4-pentaneclionate)) is dried under vacuum to rapidly achieve continuous TiO2 layers. We refer to this as gas-phase quenching. This results in thin (60±10 nm), uniform and pinhole-free TiO2 films. The PSCs based on the gas-phase quenched TiO2 exhibits improved power conversion efficiency, with a median value of 18.23% (champion value of 20.43%), compared to 9.03% and 14.09% for the untreated devices. Gas-phase quenching is further shown to be effective in enabling efficient charge transfer at the MAPbI3/TiO2 heterointerface. Furthermore, the stability of the gas-phase quenched devices is enhanced in ambient air as well as under 1-sun illumination. In addition, we achieve 12.1% efficiency in upscaled devices (1.1 cm2 active area).

The dynamic restructuring of metal nanoparticle surfaces is known to greatly influence their catalytic, electronic transport, and chemical binding functionalities. Here we show for the first time that non-equilibrium atomic-scale lattice defects can be detected in nanoparticles by purely optical means. These fluctuating states determine interface electronic transport for molecular electronics but because such rearrangements are low energy, measuring their rapid dynamics on single nanostructures by X-rays, electron beams, or tunnelling microscopies, is invasive and damaging. We utilise nano-optics at the sub-5nm scale to reveal rapid (on the millisecond timescale) evolution of defect morphologies on facets of gold nanoparticles on a mirror. Besides dynamic structural information, this highlights fundamental questions about defining bulk plasma frequencies for metals probed at the nanoscale., Dynamic restructuring of metal nanoparticle surfaces greatly influences their catalytic, electronic transport, and chemical binding functionalities. Here, the authors show that non-equilibrium atomic-scale lattice defects can be detected in nanoparticles by using nano-optics at the sub-5nm scale.

Halide double perovskites have gained significant attention, owing to their composition of low-toxicity elements, stability in air and long charge-carrier lifetimes. However, most double perovskites, including Cs2AgBiBr6, have wide bandgaps, which limit photo conversion efficiencies. The bandgap can be reduced through hallowing with Sb3+, but Sb-rich alloys are difficult to synthesise due to the high formation energy of Cs2AgSbBr6, which itself has a wide bandgap. We develop a solution-based route to synthesis phase-pure Cs2Ag(SbxBi1-x)Br6 thin films, with the mixing parameter x continuous varying over the entire composition range. We reveal that the mixed alloys (x between 0.5 and 0.9) demonstrate smaller bandgaps (as low as 2.08 eV) than the pure Sb- (2.18 eV) and Bi-based (2.25 eV) compounds, with strong deviation from Vegard's law. Through in-depth computations, we propose that bandgap lowering arises from the Type II band alignment between Cs2AgBiBr6 and Cs2AgSbBr6. The energy mismatch between the Bi and Sb s and p atomic orbitals, coupled with their non-linear mixing, results in the alloys adopting a smaller bandgap than the pure compounds. Our work demonstrates an approach to achieve bandgap reduction and highlights that bandgap bowing may be found in other double perovskite alloys by pairing together materials forming a Type II band alignment., Comment: 28 pages, 4 figures

Chirality plays a major role in nature, from particle physics to DNA, and its control is much sought-after due to the scientific and technological opportunities it unlocks. For magnetic materials, chiral interactions between spins promote the formation of sophisticated swirling magnetic states such as skyrmions, with rich topological properties and great potential for future technologies. Currently, chiral magnetism requires either a restricted group of natural materials or synthetic thin-film systems that exploit interfacial effects. Here, using state-of-the-art nanofabrication and magnetic X-ray microscopy, we demonstrate the imprinting of complex chiral spin states via three-dimensional geometric effects at the nanoscale. By balancing dipolar and exchange interactions in an artificial ferromagnetic double-helix nanostructure, we create magnetic domains and domain walls with a well-defined spin chirality, determined solely by the chiral geometry. We further demonstrate the ability to create confined 3D spin textures and topological defects by locally interfacing geometries of opposite chirality. The ability to create chiral spin textures via 3D nanopatterning alone enables exquisite control over the properties and location of complex topological magnetic states, of great importance for the development of future metamaterials and devices in which chirality provides enhanced functionality., This work was funded by EPSRC Early Career Fellowship EP/M008517/1, the Winton Program for the Physics of Sustainability, and the EU CELINA COST action. D.S.-H. acknowledges a Girton College Pfeiffer scholarship and support from the EPSRC CDT in Nanoscience and Nanotechnology. A.H.-R. and S.M.V. acknowledge funding from the EU Horizon 2020 program through Marie Skłodowska-Curie Action H2020-MSCA-IF-2016-74695. C.D. acknowledges funding from Leverhulme Trust (ECF-2018-016), Isaac Newton Trust (18-08), and a L’Oréal-UNESCO UK and Ireland Fellowship for Women in Science 2019. Funding by the Spanish Ministry of Science is acknowledged, grants MAT2017-82970-C2-1-R, MAT2017-82970-C2-2-R and MAT2018-102627-T, and by Aragon Government (Construyendo Europa desde Aragón), grant E13_20R including European Social Fund. J.P.-N. acknowledges MINECO funding BES-2015-072950. S.M.V. appreciates support from EPSRC EP/M024423/1. P.F. was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, Contract No. DE-AC02-05-CH11231 (NEMM program MSMAG). These experiments were performed at MISTRAL beamline at ALBA Synchrotron with the collaboration of ALBA staff and CALIPSOplus (Grant 730872) funding.

Why do social entrepreneurs retain their faith in social entrepreneurship despite the organizational tensions and anxieties inherent to this field of practice? In this article, we employ the psychoanalytic concept of fantasy to advance knowledge on social enterprise creation. The research analyses qualitative data relating to the adoption of the Community Interest Company, a bespoke organizational form for social enterprise. We argue that social entrepreneurs adopt a specific organizational form because it represents a fantasmatic object that supports their desire for pro-social work. This fantasmatic form appears to temporarily neutralize tensions and anxieties while preserving attachments to pro-social ideals. Our first contribution is to extant research on the role of fantasy in social enterprise. Specifically, we elucidate how social enterprise creation is riven with fantasy-laden attachments to ideals of pro-social work that promise to counteract concerns about future viability as well as competing social and for-profit missions. Our second contribution is to highlight the role that organizational form choice plays in effectively managing such tensions and anxieties as it provides a robust anchor for pro-social desires. Fantasmatic attachments to pro-social work and organizational form thus emerge as integral to social enterprise creation. This research was funded by Isaac Newton Trust and Edmond de Rothchild Foundations. peer-reviewed

Bismuth oxyiodide (BiOI) has gained attention for photovoltaics, photocatalysis and photodetectors owing to its composition of non-toxic elements, tolerance to point defects, and highly-suitable optical properties. But like many other bismuth-based compounds, BiOI is a layered material with anisotropic transport properties, making control over the preferred orientation critical for achieving optimal device performance. In this work, we develop new insights into the growth mechanism of BiOI synthesized by chemical vapor deposition (CVD) and show how the preferred orientation can be controlled. By adjusting the precursor and substrate temperatures to tune whether or not we are in a nucleation- or growth-controlled regime, we reproducibly vary the ratio of the (001) and (110) orientations by over two orders of magnitude. As a result, we achieve highly c-axis oriented films, which leads to less shunting than a/b-axis oriented films, resulting in improved open-circuit voltages from a median value of 0.7 V (a/b-axis oriented) to 0.9 V (c-axis oriented) in BiOI solar cells. More broadly, the described mechanisms can be used to control the preferred orientation in other low-dimensional materials, which will be important for achieving improved performance across a wide variety of devices.

Halide perovskite semiconductors have risen to prominence in photovoltaics and light‐emitting diodes (LEDs), but traditional oxide perovskites, which overcome the stability limitations of their halide counterparts, have also recently witnessed a rise in potential as solar absorbers. One of the many important factors underpinning these developments is an understanding of the role of dimensionality on the optoelectronic properties and, consequently, on the performance of the materials in photovoltaics and LEDs. This review article examines the role of structural and electronic dimensionality, as well as form factor, in oxide and halide perovskites, and in lead‐free alternatives to halide perovskites. Insights into how dimensionality influences the band gap, stability, charge‐carrier transport, recombination processes and defect tolerance of the materials, and the impact these parameters have on device performance are brought forward. Particular emphasis is placed on carrier/exciton‐phonon coupling, which plays a significant role in the materials considered, owing to their soft lattices and composition of heavy elements, and becomes more prominent as dimensionality is reduced. It is finished with a discussion of the implications on the classes of materials future efforts should focus on, as well as the key questions that need to be addressed.

Manuel, Marc de et al., Our closest living relatives, chimpanzees and bonobos, have a complex demographic history. We analyzed the high-coverage whole genomes of 75 wild-born chimpanzees and bonobos from 10 countries in Africa. We found that chimpanzee population substructure makes genetic information a good predictor of geographic origin at country and regional scales. Multiple lines of evidence suggest that gene flow occurred from bonobos into the ancestors of central and eastern chimpanzees between 200,000 and 550,000 years ago, probably with subsequent spread into Nigeria-Cameroon chimpanzees. Together with another, possibly more recent contact (after 200,000 years ago), bonobos contributed less than 1% to the central chimpanzee genomes. Admixture thus appears to have been widespread during hominid evolution., M.d.M. is supported by a Formació de personal Investigador fellowship from Generalitat de Catalunya (FI_B01111). M.K. is supported by a Deutsche Forschungsgemeinschaft fellowship (KU 3467/1-1). V.C.S., I.D., and L.E. are supported by Swiss National Science Foundation grants 31003A-143393 and 310030B-16660. T.D. is funded by the Gates Cambridge Trust. O.L. is supported by a Ramón y Cajal grant from Ministerio de Economía y Competitividad (MINECO) (RYC-2013-14797) and MINECO grant BFU2015-68759-P [Fondo Europeo de Desarrollo Region (FEDER)]. P.H. is supported by Estonian Research Council grant PUT1036. J.M.S., A.M.A., and S.C. are funded by the Max Planck Society. J.P.-M., C.T.-S., and Y.X. were supported by The Wellcome Trust (098051). J.M.H.-G. is supported by the María de Maeztu Programme (MDM-2014-0370). A.S. is supported by an Isaac Newton Trust/Wellcome Trust Institutional Strategic Support Fund Joint Research Grant. J.N. had support from a U.S. NIH U01CA198933 grant, and B.M.P. is supported by a Swiss National Science Foundation postdoctoral fellowship. A.N. is supported by MINECO grant BFU2015-68649-P. The collection of fecal samples was supported by the Max Planck Society and Krekeler Foundation’s generous funding for the Pan African Programme. T.M.-B. thanks ICREA; the European Molecular Biology Organization Young Investigator Programme 2013; MINECO grants BFU2014-55090-P (FEDER), BFU2015-7116-ERC, and BFU2015-6215-ERCU01; U.S. NIH grant MH106874; Fundacio Zoo Barcelona; and Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya for the support to his laboratory.

We combine data from the Sloan Digital Sky Survey (SDSS) and the Galaxy Evolution Explorer (GALEX) to simultaneously analyse optical spectra and ultraviolet photometry of 231 643 galaxies with the STARLIGHT spectral synthesis code using state-of-the-art stellar population models. We present a new method to estimate GALEX photometry in the SDSS spectroscopic aperture, which proves quite reliable if applied to large samples. In agreement with previous experiments with CALIFA, we find that adding UV constraints leads to a moderate increase on the fraction of 10-10 yr populations and a concomitant decrease of younger and older components, yielding slightly older luminosity-weighted mean stellar ages. These changes are most relevant in the low-mass end of the blue cloud. An increase in dust attenuation is observed for galaxies dominated by young stars. We investigate the contribution of different stellar populations to the fraction of light in GALEX and SDSS bands across the UV optical colour-magnitude diagram. As an example application, we use this Λdependence to highlight differences between retired galaxies with and without emission lines. In agreement with an independent study by Herpich et al., we find that the former shows an excess of inter mediate-age populations when compared to the later. Finally, we test the suitability of two different prescription for dust, finding that our data set is best-fitting using the attenuation law of starburst galaxies. However, results for the Milky Way extinction curve improve with decreasing τ, especially for edge-on galaxies.© 2018 The Author(s)., This study was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior -Brasil (CAPES) - Finance Code 001. AW, RCF, NVA, and FRH acknowledge the support from the CAPES CSF-PVE project 88881.068116/2014-01. NVA acknowledges support of the Royal Society and the Newton Fund via the award of a Royal Society-Newton Advanced Fellowship (grant NAF\R1\180403), and of Fundacao de Amparo a Pesquisa e Inovacao do Estado de Santa Catarina - FAPESC and Conselho Nacional de Desenvolvimento Cientifico e Tecnologico - CNPq. RGD thanks support from the Spanish Ministerio de Economia y Competitividad through the project AyA2016-77846-P. GB acknowledges financial support through PAPIIT project IG100115 from DGAPA-UNAM. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England.

Reproducible confinement of light on the nanoscale is essential for the ability to observe and control chemical reactions at the single-molecule level. Here we reliably form millions of identical nanocavities and show that the light can be further focused down to the subnanometer scale via the creation of picocavities, single-adatom protrusions with angstrom-level resolution. For the first time, we stabilize and analyze these cavities at room temperatures through high-speed surface-enhanced Raman spectroscopy on specifically selected molecular components, collecting and analyzing more than 2 million spectra. Data obtained on these picocavities allows us to deduce structural information on the nanoscale, showing that thiol binding to gold destabilizes the metal surface to optical irradiation. Nitrile moieties are found to stabilize picocavities by 10-fold against their disappearance, typically surviving for >1 s. Such constructs demonstrate the accessibility of single-molecule chemistry under ambient conditions., We acknowledge financial support from EPSRC Grants EP/L027151/1 and EP/N020669/1. C.C. acknowledges support from NPL PO443073. B.d.N. acknowledges support from the Leverhulme Trust and Isaac Newton Trust. R.C. acknowledges financial support from a Junior Research Fellowship of Trinity College.

Disentangling species boundaries and phylogenetic relationships within recent evolutionary radiations is a challenge due to the poor morphological differentiation and low genetic divergence between species, frequently accompanied by phenotypic convergence, interspecific gene flow and incomplete lineage sorting. Here we employed a genotyping-by-sequencing (GBS) approach, in combination with morphometric analyses, to investigate a small western Mediterranean clade in the flowering plant genus Linaria that radiated in theQuaternary.After confirming the morphological and genetic distinctness of eight species, we evaluated the relative performances of concatenation and coalescent methods to resolve phylogenetic relationships. Specifically, we focused on assessing the robustness of both approaches to variations in the parameter used to estimate sequence homology (clustering threshold). Concatenation analyses suffered from strong systematic bias, as revealed by the high statistical support for multiple alternative topologies depending on clustering threshold values. By contrast, topologies produced by two coalescent-based methods (NJst, SVDquartets) were robust to variations in the clustering threshold. Reticulate evolution may partly explain incongruences between NJst, SVDquartets and concatenated trees. Integration of morphometric and coalescent-based phylogenetic results revealed (i) extensive morphological divergence associated with recent splits between geographically close or sympatric sister species and (ii) morphological convergence in geographically disjunct species. These patterns are particularly true for floral traits related to pollinator specialization, including nectar spur length, tube width and corolla color, suggesting pollinatordriven diversification. Given its relatively simple and inexpensive implementation, GBS is a promising technique for the phylogenetic and systematic study of recent radiations, but care must be taken to evaluate the robustness of results to variation of data assembly parameters., This work was supported by the Marie Curie Intra-European Fellowship LINARIA-SPECIATION (FP7-PEOPLE-2013-IEF, project reference 624396) and an Isaac Newton Trust Research Grant (Trinity College, Cambridge)

High Intensity Focused Ultrasound (HIFU) is a non-invasive, non-ionising technology which can selectively occlude blood vessels. In Twin-Twin Transfusion Syndrome (TTTS), anastomotic placental vessels in a shared placenta allow uneven blood distribution between the twins. Despite advances in prenatal and neonatal care, TTTS remains the leading cause of death and disability in twins. Invasive fetoscopic laser can divide anastomoses, with risks of miscarriage, placental haemorrhage, extreme prematurity or second trimester rupture of membranes. Fetoscopic laser has undergone improvements in technology and therapeutic protocols over two decades, but it still does not consistently improve survival or decrease severe neurological morbidity in surviving twins. Hence, it is only used in severe cases, where benefits outweigh risks, and over 16-18 weeks gestation, after chorion and amnion fusion. This represents an unmet clinical need, which could be addressed by ultrasound-guided HIFU (USgHIFU). Selective occlusion of placental vessels using HIFU has not been described. Ultrasound identification of placental vascular anastomoses in humans is described, but is not in routine clinical use. Therefore, we tested the efficacy and safety of using USgHIFU as a non-invasive method of placental vascular occlusion in the pregnant sheep. An iterative study design in six animal groups was used. Treatment protocols for ultrasound guidance and HIFU delivery were developed in three animal groups. The efficacy and rates of associated direct and indirect iatrogenic harm of each version of the protocol was tested in another three animal groups, using invasive and non-invasive measures. Overall, transdermal USgHIFU occluded 97% of target placental vessels in the most developed treatment protocol. This persisted for 21 days and showed evidence of permanent vessel occlusion by fibrosis obliterans. This was achieved without significant adverse events, although maternal skin (2%), uterine (1%) and fetal skin burns (1%) were observed. There were no long term effects (up to 21 d) of the technique based on assessment of maternal and fetal cardiovascular, metabolic, endocrine and obstetric outcomes, or evidence of fetal compromise. This study is proof of principle that USgHIFU can be used to occlude placental vessels in the pregnant sheep. There is a low rate of direct iatrogenic harm and no evidence of indirect harm associated with the technique. As such, this supports the concept of future translational studies to develop USgHIFU as a treatment for TTTS in humans. Open Access

In pursuit of a tractable bioassay to assess blood prion infectivity, we have generated prion protein (PrP) transgenic Drosophila, which show a neurotoxic phenotype in adulthood after exposure to exogenous prions at the larval stage. Here, we determined the sensitivity of ovine PrP transgenic Drosophila to ovine prion infectivity by exposure of these flies to a dilution series of scrapie-infected sheep brain homogenate. Ovine PrP transgenic Drosophila showed a significant neurotoxic response to dilutions of 10(-2) to 10(-10) of the original scrapie-infected sheep brain homogenate. Significantly, we determined that this prion-induced neurotoxic response in ovine PrP transgenic Drosophila was transmissible to ovine PrP transgenic mice, which is indicative of authentic mammalian prion detection by these flies. As a consequence, we considered that PrP transgenic Drosophila were sufficiently sensitive to exogenous mammalian prions to be capable of detecting prion infectivity in the blood of scrapie-infected sheep. To test this hypothesis, we exposed ovine PrP transgenic Drosophila to scrapie-infected plasma, a blood fraction notoriously difficult to assess by conventional prion bioassays. Notably, pre-clinical plasma from scrapie-infected sheep induced neurotoxicity in PrP transgenic Drosophila and this effect was more pronounced after exposure to samples collected at the clinical phase of disease. The neurotoxic phenotype in ovine PrP transgenic Drosophila induced by plasma from scrapie-infected sheep was transmissible since head homogenate from these flies caused neurotoxicity in recipient flies during fly-to-fly transmission. Our data show that PrP transgenic Drosophila can be used successfully to bioassay prion infectivity in blood from a prion-diseased mammalian host.

Floyd, Suzanne et al., Spatiotemporal regulation of mitotic kinase activity underlies the extensive rearrangement of cellular components required for cell division. One highly dynamic mitotic kinase is Aurora-B (AurB), which has multiple roles defined by the changing localisation of the chromosome passenger complex (CPC) as cells progress through mitosis, including regulation of cytokinesis and abscission. Like other mitotic kinases, AurB is a target of the anaphase-promoting complex (APC/C) ubiquitin ligase during mitotic exit, but it is not known if APC/C-mediated destruction plays any specific role in controlling AurB activity. We have examined the contribution of the Cdh1 coactivator-associated APC/CCdh1 to the organization of AurB activity as cells exit mitosis and re-enter interphase. We report that APC/ CCdh1-dependent proteolysis restricts a cell-cortex-associated pool of active AurB in space and time. In early G1 phase this pool of AurB is found at protrusions associated with cell spreading. AurB retention at the cortex depends on a formin, FHOD1, critically required to organize the cytoskeleton after division. We identify AurB phosphorylation sites in FHOD1 and show that phosphomutant FHOD1 is impaired in post-mitotic assembly of oriented actin cables. We propose that Cdh1 contributes to spatiotemporal organization of AurB activity and that organization of FHOD1 activity by AurB contributes to daughter cell spreading after mitosis. © 2013 Published by The Company of Biologists Ltd., This work was supported by a Medical Research Council Career Development Award [grant number G120/892 to C.L.]; the Deutsche Forschungsgemeinschaft [grant numbers FA 378/6-2 to O.T.F., GRK1188 fellowship to S.K.]; the Isaac Newton Trust. (to C.L.); a Biochemical Society Summer Studentship (to N.W.); Consolider [grant number CSD2009-00016 to M.P.G.]; and Ministerio de Ciencia e Innovación, Spain, through JdC and Jose Castillejo programs.

The Spectrin cytoskeleton crosslinks actin to the membrane, and although it has been greatly studied in erythrocytes, much is unknown about its function in epithelia. We have studied the role of Spectrins during epithelia morphogenesis using the Drosophila follicular epithelium (FE). As previously described, we show that α-Spectrin and β-Spectrin are essential to maintain a mono-layered FE, but, contrary to previous work, Spectrins are not required to control proliferation. Furthermore, spectrin cells show differentiation and polarity defects only in the ectopic layers of stratified epithelia, similar to integrin mutants. Our results identify α-Spectrin and integrins as novel regulators of apical constriction-independent cell elongation, as α-spectrin and integrin cells fail to columnarize. Finally, we show that increasing and reducing the activity of the Rho1-myosin-II pathway enhances and decreases multi-layering of α-spectrin cells, respectively. Similarly, higher myosin-II activity enhances the integrin multi-layering phenotype. This work identifies a primary role for α-Spectrin in controlling cell shape, perhaps by modulating actomyosin. All together, we suggest that a functional Spectrin-Integrin complex is essential to balance adequate forces, in order to maintain a mono-layered epithelium., This work was supported by the Singapore Ministry of Education [Master Scholarship EDUN N23-03-044 to B.F.N.]; the Biotechnology and Biological Sciences Research Council (BBSRC) [RG42522 to I.A.G.; BB/L001748/1 to G.K.S. and I.M.P.]; the Wellcome Trust [087899/Z/08/Z to I.A.G. and I.M.P.]; the Isaac Newton Trust (Cambridge, UK) [11.35(af ) to I.A.-G.]; the FEDER programme [BFU2013-48988-C2-1-P to C.S.-C.M. and M.D.M.-B.]; Junta de Andalucía [Proyecto de Excelencia P09-CVI-5058 to C.S.-C.M. and M.D.M.-B.]; a Superior Council for Scientific Research (CSIC) JAE-DOC (to I.G.); and the Department of Zoology (Cambridge) and the University of Cambridge (I.M.P.).

This paper is part of the Special Topic on Emerging Materials and Devices for Efficient Light Generation., S.M. acknowledges financial support from the Futaba electronics Memorial Foundation. R.J.H. acknowledges support from the University of Minnesota College of Science and Engineering and Ronald L. and Janet A. Christenson. M.A. acknowledges support by the Royal Academy of Engineering under the Research Fellowship programme and by the Leverhulme Early Career Fellowship (Grant Agreement No. ECF-2019-224) funded by the Leverhulme Trust and the Isaac Newton Trust. G.L. acknowledges financial support from the European Research Council (ERC) under the European Union's Horizon 2020 Research and Innovation Programme (NANOPHOM, Grant Agreement No. 715832).