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High Potential Isoindoline‐Based Nitroxides Posolytes for Aqueous Organic Redox Flow Batteries
No full textInternational audienceThe growing transition from fossil fuels to renewable energy sources such as wind and solar requires efficient stationary energy storage systems to ensure grid stability. Among emerging technologies, redox flow batteries (RFBs) offer a promising solution due to their unique decoupling of energy and power capacities, allowing flexible system design. Recent advances in organic RFBs (ORFBs) have highlighted redox‐active organic molecules as sustainable alternatives to conventional vanadium‐based systems, addressing issues of cost and corrosivity. In particular, nitroxide radicals such as tetramethylpiperidinyloxyl (TEMPO) derivatives have demonstrated high reversibility and fast kinetics in aqueous systems, though the stability of their oxidized N‐oxoammonium form remains a challenge for long‐term storage. Isoindoline‐based nitroxides offer potential for enhanced stability but have been limited by complex and low‐yield synthetic routes. Herein, we present a convenient metal‐catalyzed [2 + 2 + 2] intermolecular cycloaddition strategy for the synthesis of isoindoline‐based nitroxides and their aza analogs, including two new candidates, TC‐TMIO and PPO. Electrochemical characterization reveals that PPO, a cationic 2,3‐dihydropyrrolo[3,4‐c]pyridinium nitroxide, exhibits an oxidation potential 220 mV higher than the benchmark 4‐TMA‐TEMPO and achieves solubility exceeding 3 M in 1 M NaCl aqueous solution. Preliminary stability assessments of the PPO and RFB testing using a methyl viologen/PPO system demonstrate its potential as a high‐performance, sustainable posolyte for aqueous ORFBs
P0489 Artificial Intelligence versus conventional scoring for assessing small bowel capsule endoscopy cleanliness in Crohn’s disease
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Microdosimetry Maps in Continuous and Pulsed Alpha Beams
No full textInternational audienceThe experimental assessment of the linear energy transfer (LET) at micrometric scale with high resolution is mandatory to achieve biologically optimized treatment plans in hadron therapy. Therefore, it is crucial to create active radiation sensors able to quantify microdosimetry distributions in three-dimensions under clinical conditions. We have quantified the first microdosimetry 2D-maps delivered by alpha beams with the highest resolution so far (400 μm × 600 μm) using a customized sensor. It consists of 3 multi-arrays of 50 3 × 3 microdetectors with a pitch of 200 μm that cover a total radiation sensitive area of 9 cm × 0.4 mm. The microdetectors are based on a novel 3D-cylindrical silicon architecture with 25-μm diameter and 20-μm thickness. The back-side of these sensors is etched to avoid back-scattering contributions in heavy ion fields. This system was calibrated with alpha beams from 5.75 to 20 MeV in the Accelerateur Lineaire et Tandem a Orsay (ALTO), France, and irradiated with pulsed beams (from 1.4 μs to 3.3 μs pulse widths) of 7.5 MeV alphas in the Centro de Micro-Analisis de Materiales (CMAM), Spain. We worked with clinical equivalent fluence rates in both continuous irradiation mode (~ 10 cm-2s-1) and in pulsed regimes with higher fluence rates up to ~ 1010 cm-2-s-1. Measurements of pulse height spectra were collected with the sensor in both modes. The experimental results were crosschecked with Monte Carlo simulations using the GATE code. The simulated spectral shapes and peak positions showed good agreement with the experimental data, with relative differences of less than 3.5% for all the energies studied. Results show that the new microdosimetry array, specially manufactured for ions, is a reliable tool for LET characterization of ions in both continuous and pulsed modes
The Musical Assembly with Reincken, Buxtehude and Theile painted in 1674 by Johannes Voorhout: Reassessing its Historiography and interpretation
No full textInternational audienceThis famous group portrait of a domestic music party by Johannes Voorhout (1647-1723) has attracted a wealth of musicological studies - and far less interest from art historians - since it entered the collections of the Museum für Hamburgische Geschichte. In the thirty or more studies or commentaries devoted to this painting, the debate has focused on the identification of the two principal musicians, Johann Adam Reincken and Dietrich Buxthehude and on the represented canon. We have taken stock of what is known about these questions and we will seek to better understand other details: the identification and symbolism of the six other figures that have been rarely considered or even ignored; the very specific models of instruments represented (harpsichord, bass viola da gamba, lute); the allegorical significance of this assembly in Reincken's career; and finally the originality of this group portrait, which seems almost unique in the production of collective portraits of musicians (artists generally represent them in their official activities) and which should be considered in the broader typology of portraits of artist-friends. Why did Reincken, who may have suggested all these programmatic intentions to the painter Voorhout, his friend and portraitist, wish to leave such a message to his entourage and thus to posterity?Ce célèbre portrait de groupe représentant une réunion musicale domestique, réalisé en 1674 par le peintre Johannes Voorhout (1647-1723), a fait l'objet de nombreuses études musicologiques – mais a suscité beaucoup moins d'intérêt de la part des historiens de l'art – depuis son entrée dans les collections du Museum für Hamburgische Geschichte. Dans la trentaine d'études ou de commentaires consacrés à ce tableau, le débat s'est concentré sur l'identification des deux musiciens principaux, Johann Adam Reincken et Dietrich Buxthehude et sur le répertoire représenté. Nous avons fait le point sur ce que l'on sait de ces questions et nous chercherons à mieux comprendre d'autres détails : l'identification et la symbolique des six autres personnages qui ont été rarement pris en considération, voire ignorés ; les modèles très spécifiques d'instruments représentés (clavecin, basse de viole, luth); la signification allégorique de cet assemblage dans la carrière de Reincken ; et enfin l'originalité de ce portrait de groupe, qui semble presque unique dans la production de portraits collectifs de musiciens (les artistes les représentent généralement dans leurs activités officielles) et qui devrait être considéré dans la typologie plus large des portraits d'amis artistes. Pourquoi Reincken, qui a peut-être suggéré toutes ces intentions programmatiques au peintre Voorhout, son ami et portraitiste, a-t-il souhaité laisser un tel message à son entourage et donc à la postérité
Investigating the role of climate change in the 3 May 2025 Western Europe hailstorm using atmospheric analogues
No full textInternational audienceOn 3 May 2025, a severe hailstorm struck Paris and parts of western Europe, raising concerns about the influence of climate change. We analyze this event using ERA5 reanalysis and an analogue-based attribution framework. The synoptic setting involved a cut-off low and a surface cold front, occurring shortly after an early-season heatwave. We compare analogous patterns in past (1974–1999) and recent (1999–2024) climates to assess thermodynamic differences. Hail probability and size were estimated with two models: a logistic formulation based on convective available potential energy, wind shear, and convective precipitation, and a new model incorporating freezing-level height and 850 hPa temperature, designed for European hail environments. Both were calibrated with Ile-de-France observations and validated with independent data. Our findings show that present-day conditions favor higher hail probabilities and larger hailstones, suggesting anthropogenic warming has likely enhanced hailstorm intensity in the region
Experimental Realization of the Markov Chain Monte Carlo Algorithm on a Quantum Computer
No full textQuantum algorithms present a quadratically improved complexity over classical ones for certain sampling tasks. For instance, the Quantum Amplitude Estimation (QAE) algorithm promises to speedup the estimation of the mean of certain functions, given access to the quantum state corresponding to the probability distribution to be sampled from. Classically, samples are often obtained by running steps a Markov Chain. In this work, we experimentally use encodings of Markov chains to prepare quantum states and run a quantum Markov Chain Monte Carlo algorithm (qMCMC) on Quantinuum's H2 and Helios quantum computers. We demonstrate that it is possible to obtain accurate results on current Noisy Intermediate Scale Quantum (NISQ) hardware, operating directly on the physical qubits
Mechanical and Growth Anisotropy in <i>Chara corallina</i> : Challenging Green’s Hypothesis
No full textPaul Green hypothesized that growth anisotropy of plant cylindrical organs could be controlled by cell-wall elastic strain. The present study aimed to challenge this hypothesis through a robust experimental and analytical framework. By combining live-cell imaging of C. corallina internodal cells with controlled turgor pressure manipulation, we simultaneously measured, for the first time, both the growth strain rate tensor and the elastic compliance tensor derived from multiaxial mechanical testing in the same cell. Under Green's hypothesis, a significant correlation should be observed between the two tensors in all directions. Our results revealed a moderate yet significant correlation between multiaxial elastic compliances and growth strain rates most pronounced in the axial direction. The ratio of axial-to-radial elastic compliance was significantly correlated with the ratio of radial-to-axial growth strain rates. In contrast, other quantities, such as the radial compliance components or the orientations of the two tensors relative to the cell axis showed no significant correlation. Furthermore the growth strain rate tensor was strongly age-dependent in both magnitude and orientation, unlike the elastic compliance. Finally, analysis of intra-tensor variability revealed that axial and radial components were strongly correlated for both tensors, with a lowered correlation in the principal axis decomposition.</div
Reference-Free Sampling-Based Model Predictive Control
No full textInternational audienceWe present a sampling-based model predictive control (MPC) framework that enables emergent locomotion without relying on handcrafted gait patterns or predefined contact sequences. Our method discovers diverse motion patterns, ranging from trotting to galloping, robust standing policies, jumping, and handstand balancing, purely through the optimization of high-level objectives. Building on model predictive path integral (MPPI), we propose a cubic Hermite spline parameterization that operates on position and velocity control points. Our approach enables contact-making and contact-breaking strategies that adapt automatically to task requirements, requiring only a limited number of sampled trajectories. This sample efficiency enables real-time control on standard CPU hardware, eliminating the GPU acceleration typically required by other state-of-the-art MPPI methods.We validate our approach on the Go2 quadrupedal robot, demonstrating a range of emergent gaits and basic jumping capabilities. In simulation, we further showcase more complex behaviors, such as backflips, dynamic handstand balancing and locomotion on a Humanoid, all without requiring reference tracking or offline pre-training
Time‐Programable Chiroptical Response From a Möbius Totemic Architecture
No full textInternational audienceInformation handling at the molecular level can be achieved by appropriate control of the chiroptical response of a chromophore. In this context, a dynamic Möbius aromatic π-system, embedded in a 3-type chirality totem edifice, has been investigated, targeting a time-dependant protonation control of its stereoselective winding. The mono-protonation of the so-called hexaphyrin-cyclodextrin hybrid (HCD) was therefore carried out with either stable (e.g. methanesulfonic acid) or unstable (trichloroacetic acid [TCA]) acids producing a drastic increase of the chiroptical activity resulting from a favored M-twist (d.e. ∼75%). Using TCA, the mono-protonation becomes a transient state, turning the static chiroptical response into a dynamic one whose time domain varies from minutes to hours, depending on the solvent composition or the amount of acid. More importantly, the way-back process (back deprotonation), that relies on the decomposition of the Cl3CCO2– counter-anion, was significantly accelerated by exchange with Cl–. As a result, addition and trapping of Cl– anion allows to switch between a dissipative and a static chiroptical response of the TCA induced mono-protonated species. This remarkable temporal control over a chiroptical signal paves the way for the design of Möbius-type devices for molecular encoding and signaling