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Revealing the unexpected: formal charge exchanges in collisional activation of cereulide ionized molecular species
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Determination of the full orientation of a single fluorescent Terrylenemolecule using intramolecular triplet-triplet absorption
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Ethylene sulfite and vinylene carbonate additives in acetonitrile-containing electrolytes for lithium-ion batteries: SEI impedance and XPS investigation
No full textInternational audienceElectrolyte solvents play a crucial role in extending the operating temperature range of Li-ion batteries. This article emphasizes the importance of precise adjustment of the amount of vinylene carbonate (VC) additive when incorporated with ethylene sulfite (ES) into a 20 vol% acetonitrile-containing carbonate electrolyte, with the aim to achieve enhanced LiNi0.5Mn0.3Co0.2O2/graphite pouch cell power performance at −5 °C. After determining the intrinsic characteristics of the electrolyte, including its ionic conductivity, viscosity, and lithium cation solvation shell using Raman spectroscopy analysis, the Li+ cation transport properties within the SEI are meticulously examined through the study of the distribution of relaxation times (DRT) extracted from electrochemical impedance spectroscopy (EIS) spectra and its composition elucidated by infrared (IR) and X-ray photoelectron spectroscopy (XPS). This study reveals significant information about the reduction reaction mechanisms leading to varying amounts of ES, VC, lithium bis(fluorosulfonyl)imide (LiFSI), acetonitrile and carbonate reduction compounds in the SEI, some of which are suspected to be the main compounds responsible for the observed differences in power performance
Stabilisation inattendue, induite par la pression, de l'état de haut spin du fer(II) dans un réseau métallo-organique
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Torque-based immune cell chemotaxis in complex environments
No full textDirected migration in chemical gradients is crucial to the immune response, yet how immune cells navigate complex tissues remains incompletely understood. Using in vitro migration assays and theoretical modeling, we uncover distinct chemotactic strategies in two key immune cell types: neutrophils and dendritic cells (DCs). DCs actively steer toward chemokine gradients via a deterministic torque-like reorientation, while neutrophils bias movement by modulating angular noise and speed. A quantitative Fokker-Planck framework decomposes these behaviors into deterministic and stochastic components. Cytoskeletal perturbations show that microtubules enable torque-based navigation in DCs in collagen gels, whereas actomyosin contractility is required for noise modulation employed by neutrophils and DCs in 2D confined migration assays. Despite both achieving directed migration, the two strategies result in opposing macroscopic outcomes: torque-driven cells minimize dispersion, while noise-biased migration enhances population spread. These results reveal distinct navigation aligned with immune function and demonstrate that immune cell chemotaxis is tuned by cytoskeletal architecture and environmental context
Ti3C2Tx MXenes: From Recovery of Pb from Perovskite Solar Cells to Supercapacitor Usage
No full textInternational audienceSustainable disposal and valorization of recovered lead from end-of-life perovskite solar cells (PSCs) remain critical challenges from environmental and electrochemical perspectives. Here, we demonstrate a dual-function process wherein Ti3C2Tx MXenes adsorbents are first employed to recover lead from green acetone-based PSC recycling waste and subsequently repurposed as high-performant supercapacitor electrode active materials. Remarkably, Ti3C2Tx achieves >99.9% Pb2+ ion removal from 100 ppm Pb/acetone solutions, with an adsorption capacity reaching up to 555 mg·g −1 . After adsorption, the Pb-loaded MXene (Ti3C2Tx/Pb ads ) retains its structural integrity and exhibits significantly enhanced electrochemical performance. Electrochemical cycling in a sodium acetate aqueous electrolyte reveals a doubled specific capacity of the MXenes, from ca. 30 C·g −1 to ca. 60C·g −1 , by introducing reversible Pb2+/Pb0 redox activity while maintaining the initial MXene pseudocapacitive behavior. Overall, this conceptual study demonstrates a closed circular materials loop by recovering a green solvent from the PSC recycling, while transforming a hazardous waste stream into a value-added energy storage material
Sub-second spin and lifetime-limited optical coherences in Yb:CaWO
No full textOptically addressable solid-state spins have been extensively studied for quantum technologies, offering unique advantages for quantum computing, communication, and sensing. Advancing these applications is generally limited by finding materials that simultaneously provide lifetime-limited optical and long spin coherences. Here, we introduce Yb ions doped into a CaWO crystal. We perform high-resolution spectroscopy of the excited state, and demonstrate all-optical coherent control of the electron-nuclear spin ensemble. We find narrow inhomogeneous broadening of the optical transitions of 185 MHz and radiative-lifetime-limited coherence time up to 0.75 ms. Next to this, we measure a spin-transition ensemble line width of 5 kHz and electron-nuclear spin coherence time reaching 0.15 seconds at zero magnetic field between 50 mK and 1 K temperatures. These results demonstrate the potential of Yb:CaWO as a low-noise platform for building quantum technologies with ensemble-based memories, microwave-to-optical transducers, and optically addressable single-ion spin qubits
Investigation of the binding mode of clobenprobit at CXCR4 and development of novel anti-inflammatory compounds with enhanced activity and minimal antagonist effects
No full textInternational audienceIntroduction Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by an overactive immune response, particularly involving excessive production of type I interferons. This overproduction is driven by the phosphorylation of IRF7, a crucial factor in interferon gene activation. Current treatments for SLE are often not very effective and can have serious side effects. Methods Our study introduces clobenpropit, a histamine analogue, as a potential new therapy targeting the CXCR4 receptor to reduce IRF7 phosphorylation and subsequent interferon production. We employed various laboratory techniques to investigate how clobenpropit interacts with CXCR4 and its effects on immune cells from healthy individuals and SLE patients. Results Clobenpropit binds effectively to CXCR4, significantly inhibiting IRF7 phosphorylation and reducing interferon production. Additionally, clobenpropit lowered levels of pro-inflammatory cytokines in a mouse model of lupus, demonstrating efficacy comparable to the standard treatment, prednisolone. Discussion These results suggest that clobenpropit could be a promising new treatment for SLE, offering a targeted approach with potential advantages over current therapies
Clarifying the origin of molecular O2 in cathode oxides
No full textInternational audienceAnionic redox has reshaped the conventional way of exploring advanced cathode materials for Li-ion batteries. However, how anions participate in the redox process has been the subject of intensive debate, evolving from electron holes to O-O dimerization and currently to a focus on trapped molecular O2 based on high-resolution resonant X-ray inelastic scattering research. Here we show that the resonant X-ray inelastic scattering signal of molecular O2 is not exclusive to Li-rich oxide cathodes, but appears consistently in O-redox-inactive oxide materials even with a short beam exposure time as low as 1 min, indicating that molecular O2 species are not directly related to voltage hysteresis and voltage decay. We further demonstrated that molecular O2 is not a direct product of electrochemistry but more likely a consequence of the core excitation process in resonant X-ray inelastic scattering, for which the possible scenarios of the dissociation of 'M-(O-O)'-like species on beam excitation must be considered. Collectively, our results reconcile the conflicting reported results on the (non-)observation of molecular O2 signal collected from different beamlines and suggest that molecular O2 is not the energetic engine of new battery oxide cathodes
Strategies for Quasi‐2D Integration in Perovskite p‐i‐n Solar Cells
No full textInternational audienceUntil recently, bulky ammonium cations, or 2D cations, one of the most promising avenues for interface passivation, have been applied almost exclusively to the p‐type interface of the n‐i‐p architecture. As the perovskite photovoltaics community gradually moves toward the inverse architecture (p‐i‐n), the question of whether to integrate 3D/2D interfaces at the interface between perovskite and the N‐type contact layer is only natural. By comparing different integration strategies, this work highlights the importance of solvent engineering and additive strategies to integrate quasi‐2D perovskite in p‐i‐n devices. It is demonstrated that these strategies enable almost complete conversion of lead iodide (PbI 2 ) excess through its conversion to quasi‐2D phases, result in a quasi‐Fermi level splitting (QFLS) gain of up to 40 meV, and promote the emergence of quasi‐2D phases of higher dimensions, which are less detrimental to electron extraction. Increasing device efficiency and stability using 2D cations, however, remains a challenge for the p‐i‐n architecture due to the quasi‐2D phases’ intrinsic properties and interfacial mechanical stress at the nanoscale. It is anticipated that, to take full advantage of quasi‐2D perovskites’ superior stability and passivating power, one needs to gain control over the homogeneity, thickness, and phase of the low‐dimensionality layer