Ever since the discovery that Mn was required for oxygen evolution in plants by Pirson in 1937 and the period‐four oscillation in flash‐induced oxygen evolution by Joliot and Kok in the 1970s, ...understanding of this process has advanced enormously using state‐of‐the‐art methods. The most recent in this series of innovative techniques was the introduction of X‐ray free‐electron lasers (XFELs) a decade ago, which led to another quantum leap in the understanding in this field, by enabling operando X‐ray structural and X‐ray spectroscopy studies at room temperature. This review summarizes the current understanding of the structure of Photosystem II (PS II) and its catalytic centre, the Mn4CaO5 complex, in the intermediate Si (i = 0–4)‐states of the Kok cycle, obtained using XFELs.
Water oxidation reaction in nature is catalysed by the Mn4CaO5 cluster in Photosystem II. We have developed operando X‐ray crystallography and X‐ray spectroscopy methods at the X‐ray free‐electron laser facilities and applied them to understand the catalytic mechanism and associated protein dynamics in Photosystem II.
For 10,000 years pigs and humans have shared a close and complex relationship. From domestication to modern breeding practices, humans have shaped the genomes of domestic pigs. Here we present the ...assembly and analysis of the genome sequence of a female domestic Duroc pig (Sus scrofa) and a comparison with the genomes of wild and domestic pigs from Europe and Asia. Wild pigs emerged in South East Asia and subsequently spread across Eurasia. Our results reveal a deep phylogenetic split between European and Asian wild boars ∼1 million years ago, and a selective sweep analysis indicates selection on genes involved in RNA processing and regulation. Genes associated with immune response and olfaction exhibit fast evolution. Pigs have the largest repertoire of functional olfactory receptor genes, reflecting the importance of smell in this scavenging animal. The pig genome sequence provides an important resource for further improvements of this important livestock species, and our identification of many putative disease-causing variants extends the potential of the pig as a biomedical model.
Low-grade thermal desalination can contribute to reduce the energy and carbon footprint of the water sector since it can be coupled to both waste heat and renewable energy sources. In this work we ...present a new process, named FlashME, that integrates MSF and MED architectures in an innovative and compact configuration able to obtain desalinated water from non-conventional sources with the highest energy and exergy efficiency. The paper presents the overall process scheme and the related simulation campaign carried in the Aspen Plus environment. The sensitive analysis is implemented to highlight the effect of main independent variables and operative parameters. The results point out the role of the first flashing temperature that should be reduced as much as possible (in relation to the allowable temperature differences between stages) to increase the thermodynamic performances. FlashME simulations are compared with the data available from recent work on low-temperature MED and different “boosted-MED” configurations showing better performances, in particular at very low top brine temperatures where it shows the highest II-law efficiencies among the available thermal processes. In comparison with MED-based and boosted-MED configurations, this system has the advantage to avoid additional flashing stages and vapor injections with the advantage of less complexity as well as improved performance along with reduced energy consumption. In the lowest temperature range (65–70 °C) the results show that the FlashME production rate is increased by 20–28% compared to FB-MED and up to 100% relative to conventional MED.
•recovering the sensible heat at low temperature with a simple and flexible architecture.•doubling the performances of conventional MED architectures.•productivity increased by at least 20% compared to “improved MED” configurations at low temperatures.•greater distillate production and/or lower number of stages.•higher exergy efficiency thanks to reduced entropy generation.
Rapid processing of tactile information is essential to human haptic exploration and dexterous object manipulation. Conventional electronic skins generate frames of tactile signals upon interaction ...with objects. Unfortunately, they are generally ill-suited for efficient coding of temporal information and rapid feature extraction. In this work, we report a neuromorphic tactile system that uses spike timing, especially the first-spike timing, to code dynamic tactile information about touch and grasp. This strategy enables the system to seamlessly code highly dynamic information with millisecond temporal resolution on par with the biological nervous system, yielding dynamic extraction of tactile features. Upon interaction with objects, the system rapidly classifies them in the initial phase of touch and grasp, thus paving the way to fast tactile feedback desired for neuro-robotics and neuro-prosthetics.
The myelination of axons by oligodendrocytes has been suggested to be modulated by experience, which could mediate neural plasticity by optimizing the performance of the circuitry. We have assessed ...the dynamics of oligodendrocyte generation and myelination in the human brain. The number of oligodendrocytes in the corpus callosum is established in childhood and remains stable after that. Analysis of the integration of nuclear bomb test-derived (14)C revealed that myelin is exchanged at a high rate, whereas the oligodendrocyte population in white matter is remarkably stable in humans, with an annual exchange of 1/300 oligodendrocytes. We conclude that oligodendrocyte turnover contributes minimally to myelin modulation in human white matter and that this instead may be carried out by mature oligodendrocytes, which may facilitate rapid neural plasticity.
Dans les années 80, Abdoulaye Mamani et Med Hondo se sont inspirés des récits oraux pour transformer Sarraounia Mangou, figure historique, en un mythe littéraire et cinématographique. Depuis lors, ...plusieurs autres types de média – chanson populaire, bande dessinée, peinture architecturale, sculpture joaillière, réseaux sociaux – reprennent à leur manière et réinscrivent dans l’imaginaire négro-africain l’épopée anti-impériale de cette monarque nigériènne. Face à cette prolifération des modes de narration, quel serait le rapport de l’oralité à l’historiographie quand le récit navigue entre plusieurs supports médiatiques, en l’occurrence scripturels, sonores, visuels, numériques? Quel rôle est assigné au griot dans ce contexte? Le présent article affirme que loin d’être de simples transcriptions de la parole du griot, les divers récits de Sarraounia s’appuient sur l’oralité non seulement comme instance achéologique de l’historiographie, mais surtout comme indice sémiologique d’interférence, d’hybridation et de différenciation.
Integrating variable and non-dispatchable renewable power generation into existing power systems will have consequences for their operation and future expansion. These impacts will depend on two ...factors: (1) the variability of the total renewable power generation on different time scales and (2) the possibilities of accurately forecasting these fluctuations. In this paper, previous research on variability assessment and forecasting of solar, wind, wave and tidal energy resources is reviewed. The aim is to summarize the state of knowledge in each area and to compare the approaches used for the respective resources. For temporal variability, methods and models used for assessing the variability are surveyed, as well as what is known about the variability at individual sites and for larger aggregates of sites. For forecasting, an overview of forecasting methods for the different resources is made, and selected forecasting methods are compared over different time horizons. An important finding is that it is hard to draw strong conclusions from the existing studies due to differences in approaches and presentation of results. There is a need for further, more coherent studies that analyze the variability for the different resources in comparable ways, using data with the same resolution, and for studies that evaluate the smoothing effect and complementarity of combinations of several renewable energy resources. For forecasting, future research should suggest ways to evaluate forecasts from different renewable energy sources in easily comparable ways, using data from the same locations or regions, with the same temporal and spatial resolution, and with comparable metrics for the forecasting errors.
The advent of machine learning‐based structure prediction algorithms such as AlphaFold2 (AF2) and RoseTTa Fold have moved the generation of accurate structural models for the entire cellular protein ...machinery into the reach of the scientific community. However, structure predictions of protein complexes are based on user‐provided input and may require experimental validation. Mass spectrometry (MS) is a versatile, time‐effective tool that provides information on post‐translational modifications, ligand interactions, conformational changes, and higher‐order oligomerization. Using three protein systems, we show that native MS experiments can uncover structural features of ligand interactions, homology models, and point mutations that are undetectable by AF2 alone. We conclude that machine learning can be complemented with MS to yield more accurate structural models on a small and large scale.
All‐polymer and paper‐based energy storage devices have significant inherent advantages in comparison with many currently employed batteries and supercapacitors regarding environmental friendliness, ...flexibility, cost and versatility. The research within this field is currently undergoing an exciting development as new polymers, composites and paper‐based devices are being developed. In this report, we review recent progress concerning the development of flexible energy storage devices based on electronically conducting polymers and cellulose containing composites with particular emphasis on paper‐based batteries and supercapacitors. We discuss recent progress in the development of the most commonly used electronically conducting polymers used in flexible device prototypes, the advantages and disadvantages of this type of energy storage devices, as well as the two main approaches used in the manufacturing of paper‐based charge storage devices.
Recent progress within the field of conducting polymer and cellulose‐based charge storage is reviewed with particular emphasis on the development of environmentally friendly, versatile and flexible paper‐based batteries and supercapacitors. The latter devices, which can be constructed from a few paper sheets, enable the realization of a range of new types of charge storage devices.
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