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The 33 rd Ion Channels Meeting, September 2024, Sète, France
No full textInternational audienceThe 33rd Ion Channels Meeting has been held in Sète, France, from September 8th to 11th. The congress gathered together senior and junior researchers from almost all over the world working on different fields of biology and pathophysiology. The colloquium opened with the plenary lecture on the action mechanisms of α2δ proteins in the trafficking of calcium channels and how these proteins can modulate the channels functional properties, given by Prof. Annette Dolphin. The five symposia of this edition were focused not only on several techniques for studying ion channels and their environment but also on ion channels and their involvement in cancer. Two symposia have been totally dedicated to genetic channelopathies, and the last one was devoted to glutamate receptors. All the presentations of the symposia are reported and summarized in this report meeting article
TorchGDM: A GPU-accelerated Python toolkit for multi-scale electromagnetic scattering with automatic differentiation
No full textInternational audienceWe present “torchGDM”, a numerical framework for nano-optical simulations based on the Green’s Dyadic Method (GDM). This toolkit combines a hybrid approach, allowing for both fully discretized nano-structures and structures approximated by sets of effective electric and magnetic dipoles. It supports simulations in three dimensions and for infinitely long, two-dimensional structures. This capability is particularly suited for multi-scale modeling, enabling accurate near-field calculations within or around a discretized structure embedded in a complex environment of scatterers represented by effective models. Importantly, torchGDM is entirely implemented in PyTorch, a well-optimized and GPU-enabled automatic differentiation framework. This allows for the efficient calculation of exact derivatives of any simulated observable with respect to various inputs, including positions, wavelengths or permittivity, but also intermediate parameters like Green’s tensor components, which can be interesting for physics informed deep learning applications. We anticipate that this toolkit will be valuable for applications merging nano-photonics and machine learning, as well as for solving nano-photonic optimization and inverse problems, such as the global design and characterization of metasurfaces, where optical interactions between structures are critical
Macroscopic Fluctuation Theory for Ginzburg–Landau Dynamics with Long-Range Interactions
No full textInternational audienc
AN OLEINIK INEQUALITY FOR A CLASS OF HETEROGENEOUS BALANCE LAWS
No full textAlthough an Oleinik inequality is not expected for general heterogeneous scalar balance laws [3], there is a favorable case, when g(x) is smooth and nondecreasing. In this setting, we are able to obtain an Oleinik-type inequality and, consequently, a smoothing effect
Uniform-in-time propagation of chaos for mean field Langevin dynamics
No full textInternational audienceWe study the mean field Langevin dynamics and the associated particle system. By assuming the functional convexity of the energy, we obtain the -convergence of the marginal distributions toward the unique invariant measure for the mean field dynamics. Furthermore, we prove the uniform-in-time propagation of chaos in both the -Wasserstein metric and relative entropy.Nous étudions la dynamique de Langevin à champ moyen et le système de particules correspondant. En supposant la convexité fonctionnelle de l’énergie, nous obtenons la convergence dans des distributions marginales vers l’unique mesure invariante pour la dynamique à champ moyen. De plus, nous montrons la propagation du chaos uniforme en temps à la fois dans la métrique de Wasserstein d’ordre 2 et dans l’entropie relative
An Electrochemical Study of Key Catalytically Active Gold Complexes
No full textInternational audienceGold catalysis has long been dominated by the ability of gold(I) to activate unsaturated systems as a carbophilic Lewis acid. However, recent advances have highlighted the significance of Au(I)/Au(III) redox transitions, unlocking new catalytic pathways. Among the strategies facilitating these oxidative processes, electrochemical anodic oxidation has emerged as a powerful tool. Despite its potential, the electrochemical properties of key gold complexes remain largely underexplored. In this study, we systematically investigate the oxidative behavior of a series of gold complexes using cyclic voltammetry. A comprehensive electrochemical scale is established, revealing that N ‐heterocyclic carbene (NHC)‐based gold complexes are among the least prone to oxidation, whereas phosphorylated ligands significantly enhance oxidizability. Within triphenylphosphine gold complexes, the nature of the X‐type anionic ligand plays a crucial role in determining oxidative behavior, a trend rationalized through density functional theory (DFT) calculations of the highest occupied molecular orbital (HOMO). Additionally, hemilabile P^N ligands dramatically facilitate oxidation, correlating with their ability to promote oxidative addition. These findings provide fundamental insights into the redox properties of gold complexes, offering valuable guidelines for the design of new gold‐catalyzed transformations
Recent Advancements in Enyne Metathesis in Nonusual Media
No full textInternational audienceAbstract This review presents seminal advancements in enyne metathesis in nonusual media, including green solvents, supercritical fluid, and microwave technology. Enyne metathesis has been recognized as a powerful and innovative transformation in modern molecular chemistry, enabling the efficient construction of complex cyclic and acyclic diene frameworks. One can differentiate the enyne cross-metathesis, where an alkyne may react with an alkene, from the ring-closing enyne metathesis, where the alkyne and alkene are part of the same molecule. Both enyne transformations will be discussed in various solvents such as water, ionic liquids, ethyl lactate, and dimethyl carbonate. The use of various ruthenium-based complexes will be compared in each case. We will finally present tandem processes implying enyne cross- or ring-closing metathesis and cyclization or reduction
Conserved architecture of a functional lncRNA-protein interaction in the DNA damage response pathway.
No full textABSTRACT Long non-coding RNA (lncRNAs) structures are emerging as key drivers in cellular functions. Unlike proteins, lncRNAs exhibit diverse patterns of conservation, reflecting the evolutionary genetic pressures they have undergone. The long intergenic non-coding RNA p21 (lincRNA-p21) is a low-conserved, mammal-specific lncRNA. It regulates the cis activation of its neighboring gene Cdkn1A, which encodes the p21 protein, an essential player in the DNA damage response. The syntenic mouse and human lincRNA-p21 genes display low sequence similarity, and their transcripts show distinct cellular localization and different additional cellular functions. Despite these evolutionarily divergent features, both transcripts interact with the same partner in the nucleus, the heterogeneous nuclear ribonucleoprotein K (hnRNP K), to regulate the expression of the Cdkn1a gene. Elucidating the molecular bases of the lincRNA-p21 interaction with hnRNP K is crucial for understanding the activation of the p21-dependent DNA damage response. However, it remains unknown which RNA and protein motifs are involved in this interaction, and whether those motifs are shared between mice and humans. To address this question, we employed in vitro , in cellulo, and ex cellulo SHAPE-MaP to determine the secondary structures of the full-length mouse (3 kb) and human (4 kb) lincRNA-p21 transcripts. We identified a conserved structural RNA motif that comprises a ∼20-nucleotide terminal stem-loop containing a conserved tetranucleotide UCAY. In silico analyses, molecular dynamics simulations, and in vitro protein-RNA binding assays support the interaction of lincRNA-p21 and this RNA motif with the KH3 domain of hnRNP K. Using eCLIP-qRT-PCR and fluorescence correlation spectroscopy (FCS), we demonstrate that a mutant lacking the conserved structural RNA motif is no longer able to bind the hnRNP K protein within cells. In conclusion, our study reveals a conserved lncRNA-protein interaction between two syntenic transcripts with divergent sequences and structures, highlighting evolutionary pressure to maintain a critical cellular stress-control element. Our data provide molecular details for targeting a specific RNA-protein interaction essential for regulating the cellular response to DNA damage
