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The Value Chain of Sustainable Dual Carbon Sodium Ion Capacitors
No full textInternational audienceNow that fast action is needed to mitigate the effects of climate change, developing new technologies to reduce the worldwide carbon footprint is critical. Sodium ion capacitors can be a key enabler for widespread transport electrification or massive adoption of renewable technologies. However, a years‐long journey needs to be made from the first proof‐of‐concept report to a degree of maturity for technology transfer to the market. To shorten this path, this work gathers all the stakeholders involved in the technical development of the sodium ion capacitor technology, covering the whole value chain from academics (TRL 1–3) and research centers (TRL3–5) to companies and end‐users (TRL 6–9). A 360‐degree perspective is given on how to focus the research and technology development of sodium ion capacitors, or related electrochemical energy storage technologies, from understanding underlying operation mechanisms to setting up end‐user specifications and industrial requirements for materials and processes. This is done not only in terms of performance metrics, but mainly considering relevant practical parameters, i. e., processability, scalability, and cost, leading up to the final sustainability evaluation of the whole of the technology by Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) analysis, which is of utmost importance for society and policymakers
High-resolution Molecular Dynamics Simulations of the Pyruvate Kinase Muscle Isoform 1 and 2 (PKM1/2)
No full textInternational audienceGlucose metabolism plays a pivotal role in both normal physiological processes and cancer cell growth. The final stage of glycolysis, converting phosphoenolpyruvate (PEP) into pyruvate, is catalyzed by the pyruvate kinase (PK) enzyme. Whereas PKM1 (isoform 1) is mainly expressed in cells with high energy requirements, PKM2 (isoform 2) is preferentially expressed in proliferating cells, including many tumor cells. Structural analysis of both PKM1 and PKM2 is essential to the design of new molecules with anti-tumor activity. To understand the structural dynamics of PKM1 and PKM2, we performed extensive high-resolution molecular dynamics (MD) simulations using adaptive sampling techniques coupled to the polarizable AMOEBA force field. Performing more than 6 s of simulation, we consider PKM2 in its various oligomerization states and propose structural insights for PKM1. We particularly focus on the structuring of key sites including the active site and the natural substrate Fructose Bi-Phosphate (FBP) fixation pocket. Additionally, we propose the first high-resolution MD simulation of the biologically active PKM1 and uncover important similarities between the constitutive, tetrameric form of PKM1 and its PKM2 counterpart bound to FBP. Finally, we analyze the impact of the fixation of TEPP-46, a pharmacological activator, on PKM2 structuring and highlight the structural differences with PKM2 bound to FBP
Chromosome mis-segregation triggers cell cycle arrest through a mechanosensitive nuclear envelope checkpoint
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Development of Ferrocenyl and Ruthenocenyl Zileuton Analogs with Enhanced Bioactivity toward Human 5-Lipoxygenase: Innovation in Drugs for Inflammatory Diseases
No full textInternational audienceZileuton is the only FDA-approved 5-lipoxygenase (5-LOX) inhibitor for asthma treatment, but it produces hepatotoxicity associated with the benzothiophene fragment. Using the concept of organometallic derivatization pioneered by Jaouen and Brocard, we synthesized five new organometallic Zileuton derivatives, maintaining the urea fragment and incorporating ferrocenyl and ruthenocenyl moiety (3a-e). Their biological activity was evaluated against 5-LOX, 15-LOX, COX-1, and COX-2 enzymes. The ferrocenyl and ruthenocenyl N-hydroxyurea complexes coined Ferroleuton (3a) and Ruthenoleuton (3e) showed the highest selective inhibitory activity against 5-LOX, with IC50 values of 0.21 ± 0.12 and 3.49 ± 1.11 µM, respectively. Notably, 3a exhibited superior activity compared to Zileuton (IC50 0.67 ± 0.09 µM), demonstrating the key role of N-hydroxyurea and ferrocenyl fragments in the inhibitory process. Worthy of note, both compounds displayed low cytotoxicity in lung fibroblast healthy cells line (MRC-5) (CC50 of 116.40 and >200 µM, respectively). Enzyme kinetic studies indicated competitive and mixed type of inhibition for 3a and 3e, respectively. Additionally, they demonstrated superior antioxidant capacity compared to Zileuton (DPPH, ABTS, and FRAP assays). Electrochemical and MD studies suggest a chelanting-redox deactivation mechanism for 5-LOX. These findings position Ferroleuton (3a) and Ruthenoleuton (3e) as promising candidates for inflammatory disease treatment.</div
Phonon properties of 2D Ti3C2Cl2 MXenes
No full textInternational audienceTailoring the surface chemistry of MXenes is crucial for tuning their electronic, optical, catalytic, and mechanical properties. Phonons play a particularly important role in determining thermal properties, while they can also influence mechanical properties and electronic behavior, e.g., through electron–phonon coupling. Here, we report the synthesis of high-quality Ti 3 C 2 Cl 2 MXenes, enabling the investigation of their intrinsic vibrational and thermal properties using a combination of in situ Raman spectroscopy, specific heat measurements, and ab initio calculations. The assessment of vibrational modes and their symmetries was based on polarized Raman spectroscopy, which revealed strong anisotropy between in-plane E and out-of-plane A 1 modes. These observations are supported by density functional perturbation theory (DFPT) calculations, showing excellent agreement with the experimental results. We demonstrate that temperature induces reversible shifts and broadening of Raman peaks, which we attribute to anharmonic effects. Specific heat measurements further provide insights into the thermal behavior and acoustic phonon modes of Ti 3 C 2 Cl 2 . We separate electron and phonon contributions to the specific heat and find evidence of the two-dimensional character of MXenes in the low temperature range — an effect often suppressed in other low-dimensional systems
Relations entre la structure et les propriétés optiques des pigments violets à base de cobalt utilisés par Robert Delaunay
No full textInternational audienceFollowing the industrial revolution and the modernization of chemistry, purple became one of the most popular colors in the palettes of late 19th- to 20th-century painters. Among them, Robert Delaunay (1885–1941) was one of the key artists of the avant-garde movement in France in the early 20th century. Although widely used in modern and contemporary paintings, inorganic purple pigments of the cobalt phosphate and cobalt arsenate families have been little studied chemically until now. The diversity of emerging chemical syntheses resulted in a wide range of products, characterized by a high diversity of hues, function of their respective composition, and crystal structures. The present work combines structural and optical analyses to probe the purple pigments used by Delaunay. Reference materials synthesized in the laboratory were characterized via synchrotron radiation-based high-angular-resolution X-ray powder diffraction and UV–vis–NIR spectroscopy. Structure–color relationships were established for the first time for several inorganic compounds of the Co–P/As family. Two of Robert Delaunay’s earliest masterpieces conserved at the Centre Pompidou in Paris were probed in situ via X-ray powder diffraction in imaging mode and fiber optic UV–vis–NIR reflectance spectroscopy. The results highlight the decisive effect of their structural chemistry on the palettes of modern and contemporary painters
Niobium Bronzoids as negative Electrodes: Synthesis, Structure and Electrochemical Properties of Li2Nb4P2O16 and Na2Nb4P2O16
No full textIn this study, sodium- and lithium-based phosphate niobium bronzes and bronzoids with the general formula Ax(PO2)2(NbO3)m (where A = Na/Li and m = 4), specifically Na2Nb4P2O16 and Li2Nb4P2O16, are investigated. The crystal structure of Na2Nb4P2O16 is revisited using a combination of laboratory and synchrotron X-ray powder diffraction. It is found to crystallize in the P21/a space group (different from the previously reported P21 space group), with lattice parameters a = 13.2503(6) Å, b = 5.3498(2) Å, c = 19.0807(7) Å, β = 109.9574o (3) and V/Z = 317.833(9) Å3. Additionally, we synthesized and solved the crystal structure of Li2Nb4P2O16 for the first time, introducing it as a lithium-based phosphate niobium bronzoid. It crystallizes in the Pc21n orthorhombic cell with lattice constants a = 6.7031(4) Å, b = 5.1936(2) Å , c = 17.4260(8) Å and V/Z = 303.324(5) Å3. As negative electrodes in Li batteries, Li2Nb4P2O16 and Na2Nb4P2O16 exhibited average discharge capacities of 386 mAh/g and 277 mAh/g, respectively, at C/15 in a voltage window of 3.0 V to 0.1 V
Contactless defects detection using modulated photoluminescence technique: model for a single Shockley-Read-Hall trap in a semiconductor thin layer
No full textInternational audienceStudying defects in semiconductors is, in practice, a very important topic for opto-electronic applications. It involves advanced characterization tools able to quantify and qualify the defect densities present in the materials. In the present article we focus on the use of a contactless frequency domain technique: modulated photoluminescence (MPL), and show its potential to detect defects. MPL has been used for the measurement of differential lifetime for several decades in silicon wafers. By extending it to low lifetime/highly defective materials we discovered its potential to become a defect spectroscopy method, measuring time constants close to the ones governing impedance spectroscopy measurements. Proofs of concept and an analytical model for doped materials have been presented already. Here, we reformulate the analytical model more explicitly and check its applicability by extensive numerical simulations for the case of a low illumination for a thin layer with a single defect. We present a parametric numerical study simulating the response of a single Shockley-Read-Hall center, showing the appearance of so-called V-Shapes in the MPL phase patterns as predicted by the analytical model, and valid beyond small-signal approximation. We discuss the difference between these two approaches and extend the analytical model and numerical investigations to intrinsic materials
Using lateral dispersion to optimise microfluidic trap array efficiency
No full textInternational audienceMicrofluidic trapping arrays have proven to be efficient tools for various applications that require working at the single-cell level, such as cell-cell communication or fusion. Although several hydrodynamic trapping devices have already been optimised, two-dimensional (2D) single-layer trapping arrays with high trap densities remain partially inefficient. Specifically, many traps remain empty, even after prolonged injection, which drastically reduces the number of samples available for post-treatment. These unfilled traps result from the symmetrical nature of the flow around the traps, and breaking this symmetry enhances capture efficiency. In this study, we use a numerical approach to show that optimal geometries can significantly increase filling efficiency and a preliminary experimental test confirming our approach is provided. We show that these improvements are achieved by promoting lateral dispersion of particles, facilitated either through an optimised oblique flow or by introducing disorder into the spatial arrangement of traps without specific inlet/outlet adjustment
Exploring Marine Biomineralization on the Al–Mg Alloy as a Natural Process for In Situ LDH Growth to Improve Corrosion Resistance
No full textInternational audienceThis study provides a detailed characterization of the AA5083 aluminum alloy, surface, and interface over 6 months of immersion in seawater, employing techniques such as SEM/EDX, GIXRD, μ-Raman and XPS. The purpose was to evaluate the evolution of the biomineralization process that occurs on the Al–Mg alloy. By investigating the specific conditions that favor the in situ growth of layered double hydroxide (LDH) during seawater immersion as a result of biomineralization, this research provides insights into marine biomineralization, highlighting its potential as an innovative and sustainable strategy for corrosion protection