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Nonlinear Optical Properties of Fe(II) and Ru(II) Alkynyl-Functionalized 1,3,5-Triphenyl-1,3,5-triazine-2,4,6-triones and 1,3,5-Triphenylbenzenes: Syntheses, Second-Harmonic Generation and Two-Photon Absorption
No full textInternational audienceWe report the use of σ-alkynyl d6 electron-rich transition metal complexes as electron-releasing end-groups in octupolar molecules designed for nonlinear optical (NLO) applications, specifically, N,N′,N″-triarylisocyanurates (5,7,8,10,12) and 1,3,5-triarylbenzenes (6,9,11) functionalized by Fe(II) and Ru(II) organometallic moieties, and their NLO properties, as assessed by hyper-Rayleigh scattering (HRS) and Z-scan. The redox properties are briefly investigated through isolation of the corresponding Fe(III) trications 5[PF6]3 and 6[PF6]3. The second-harmonic generation (SHG) or two-photon absorption (2PA) performance of the Fe(II) and Ru(II) parents is compared with the help of TD-DFT calculations performed on models. Comparison with tris-ferrocenyl isocyanurate 4 reveals that the σ-connection of the metallic centers to the π-manifold is superior to the η5-connection for enhancing NLO properties. The positive effect of organometallic end-groups on NLO properties relative to purely organic electron-releasing substituents is established. The mechanism by which NLO enhancement occurs is complex and possibly connected to the polarizable π-electrons in the ligands surrounding the metal alkynyl units, but in most cases, the observed NLO enhancement must arise from the transition metal centers interacting with the central π-manifold
Disordered harmonic chains with random masses and springs: A combinatorial approach
No full textInternational audienceWe study harmonic chains with i.i.d. random spring constants and i.i.d. random masses . We introduce a new combinatorial approach which allows to derive a compact approximate expression for the complex Lyapunov exponent, in terms of the solutions of two transcendental equations involving the distributions of the spring constants and the masses. Our result makes easy the asymptotic analysis of the low frequency properties of the eigenmodes (spectral density and localization) for arbitrary disorder distribution, as well as their high frequency properties. We apply the method to the case of power-law distributions with and with (with ). At low frequency, the spectral density presents the power law , where the exponent exhibits first order phase transitions on the line and on the line . The exponent of the non disordered chain () is recovered when and are both finite, i.e. and . The Lyapunov exponent (inverse localization length) shows also a power-law behaviour , where the exponent exhibits several phase transitions~: the exponent is for or ( or infinite) and when and ( and both finite). In the intermediate region it is given by . On the transition lines, and receive logarithmic corrections. Finally, we also consider the Anderson model with random couplings (random spring chain for ``Dyson type I'' disorder)
Experimental demonstration of coherent beam combination by a simulation-trained deep neural network
No full textInternational audienceFor phase retrieval in a coherent beam combining of 7 fiber amplifiers arranged in a tiled aperture experiment, we demonstrate the feasibility of direct implementation of a light-weight deep-learning model trained on simulated data only. Deep-learning-assisted phase control performs efficiently with lower than λ/30 residual phase error. The use of simulation-trained neural networks allows for fast training (<10 min), a priori optimization, without the need for experimental data acquisition, and easier experimental portability
Comparison of M10 and M20 Meteomodem radiosondes relative humidity measurements with ECMWF ERA5 above France: focus on the upper troposphere
No full textInternational audienceAccurate knowledge of the relative humidity (RH) in the troposphere is important for predicting cloud formation, particularly in the upper troposphere where contrails can form and contribute to global warming. However, it is difficult to predict their formation due to the lack of precise RH measurements at these altitudes. This paper compares RH data from Meteomodem radiosondes (M10 and M20) acquired over a 5-years period (2020-2024) at the Trappes and Nîmes meteorological stations in France with ECMWF ERA5 analyses, with a focus on the upper troposphere. For Trappes, two datasets exist: one processed operationally by Météo France (MF) and a second processed using the GRUAN standard. Whatever the processing is, Meteomodem radiosondes RH values are on average higher than ERA5 ones, by about 2 % at 800 hPa up to 10 % at 200 hPa. The operational MF processing generally gives higher RH than the GRUAN processing. The median difference between both processing methods is lower than 2.2 % for pressures higher than 300 hPa and is maximum for lower pressures and nighttime measurements, the GRUAN processing showing more consistency between daytime and nighttime measurements. The evolution of MF processing over time
Trial Watch - bispecific T cell engagers and higher-order multispecific immunotherapeutics
No full textInternational audienceOver the past decades, cancer immunotherapy has evolved into clinical practice, with bispecific T cell engagers (TCEs) and other higher-order multispecific immunotherapeutics emerging as approaches for precision immune modulation. These engineered antibodies redirect immune effector cells toward tumor targets, thereby eliciting coordinated antitumor immune responses. While substantial clinical success has been achieved in hematologic malignancies, major challenges, such as limited activity in solid tumors, continue to constrain broader application. In this Trial Watch, we summarize recent preclinical advances in the design and optimization of TCEs and multispecific immune engager platforms together with available clinical trial data. We further examine key pharmacokinetic, safety, resistance, and manufacturing considerations in immune engager development. Collectively, these findings highlight the increasing versatility of immune cell-redirecting immunotherapies and their pivotal role in shaping the next generation of precision cancer therapy
Immunobiological mechanisms of action of oncolytic peptides
No full textInternational audienceOncolytic peptides (OLPs) constitute an emerging class of immunotherapeutics that combine direct cancer cell lysis with immune activation. Indeed, OLPs induce rapid immunogenic cell death by disrupting intracellular membranes, which culminates with the abundant release of malignant cell contents including immunostimulatory danger-associated molecular patterns. This results in the engagement of innate immune sensors that potently activate dendritic cells, leading to the cross-priming of tumor-specific T lymphocytes that mediate systemic anticancer immunity. Through such a dual mechanism, OLPs can remodel the tumor microenvironment and overcome resistance to therapy as promoted by intratumoral heterogeneity, hence representing optimal combinatorial partners for immune checkpoint inhibitors. Some OLPs have also shown remarkable clinical efficacy. For instance, LTX-315 (studied as VP-315 in basal cell carcinoma (BCC)) has recently been shown to enable complete and durable responses in patients with BCC, and emerging evidence points to a significant activity of LTX-315 in immunologically cold tumors. Here, we summarize recent mechanistic, preclinical, and clinical advances in OLP development, underscoring their potential as a versatile and powerful modality of cancer immunotherapy
Predictive X-ray spectroscopy of actinide complexes: from HERFD-XANES to RIXS maps via relativistic quantum chemistry
No full textInternational audienceHigh-energy-resolution X-ray spectroscopies such as HERFD-XANES and Resonant Inelastic X-ray Scattering (RIXS) are powerful probes of actinide electronic structure and coordination. Predictive theoretical descriptions are particularly challenging for poorly characterized actinides.We combine HERFD-XANES experiments with relativistic quantum chemical calculations to study uranium(VI) and protactinium(V) complexes of environmental relevance. Uranylcompounds with varying ligand fields and O=U=O bending serve as benchmarks; U M4-edge HERFD-XANES spectra are interpreted using relativistic time-dependent density functionaltheory (TD-DFT) [1,2].The focus is then placed on protactinium(V) [3]. HERFD-XANES spectra at the Pa L3-edge in hydrofluoric and oxalic acid solutions show closely related features, raising questions about Pa(V)speciation and oxo bonding. These spectra are analyzed using TD-DFT together with multi-reference spin–orbit SO-RASSCF and SO-RASPT2 calculations.Predictive Pa L3-edge RIXS maps, computed exclusively with SO-RASSCF/SO-RASPT2, reveal sensitive fingerprints of metal-centered and charge-transfer excitations, providing clear targets forfuture high-resolution RIXS experiments on protactinium complexes.References:[1] W. A. Misael, A. S. P. Gomes. Core excitations of uranyl in Cs2UO2Cl4 from relativistic embedded damped response time-dependent density functional theory calculations. Inorg. Chem. 2023, 62, 29, 11589–11601.[2] W. A. Misael, J. März,, L. Amidani, E. F. Bazarkina, K. O. Kvashnina, V. Vallet, A. S. P. Gomes. Core-Excited States of Linear and Bent Uranyl Complexes: Insights from High-Energy Resolution X-raySpectroscopy and Relativistic Quantum Chemistry. Inorg. Chem. 2025, 64, 45, 22487–22502.[3] M. Maloubier, T. Shaaban, F. Réal, C. Le Naour, H. Oher, T. Aubert, P. L. Solari, B. Siberchicot, R. Maurice, V. Vallet. Speciation of Protactinium(V) in Hydrochloric Acid solutions: evidence of theProtactinium(V) Monooxo Bond Stability, Angew. Chem. Int. Ed. 2025, e18403
H.E.S.S. detection of the PSR J0855-4644 nebula
No full textInternational audienceHESS J0852-463 is a TeV γ-ray source located in the Galactic plane. The region consists of a supernova remnant (SNR, RX J0852.0-4622) with a shell-like morphology, commonly referred to as Vela Junior, and a pulsar denoted PSR J0855-4644. Pulsars are among the most efficient leptonic accelerators in our Galaxy, making this region particularly interesting to study. We utilise the most recent data taken by the High Energy Stereoscopic System (H.E.S.S.), to investigate any γ-ray emission associated with the pulsar in this region, PSR J0855-4644. We applied a full forward folding method on the H.E.S.S. data. Utilising 3D modelling techniques, we evaluated the TeV γ-ray emission towards the various components of this complex system. The distinct energy-dependent morphology observed in our data motivates further investigation of this source. We resolved the emission in the Vela Junior region into various components, several of which correspond to the SNR itself. In particular, we find a new extended component which is coincident with the position of PSR J0855-4644. The spectrum follows a power-law distribution with a best-fit index of ΓE = 1.81 ± 0.07stat which differs from the properties of the surrounding γ-ray emission of the Vela Junior SNR. A one-zone leptonic joint fit between the X-rays (from XMM-Newton) and γ-rays (from H.E.S.S.) leads to a lower limit on the magnetic field of 1.6μG and a spectral index of α = 1.88 ± 0.01, in line with expectations of pulsar wind nebulae (PWNe). In this paper, we report the first detection of the PWN of PSR J0855-4644 at TeV energies with the H.E.S.S. experiment at a significance of 12.2σ. This is attributed to the advanced techniques of the 3D analysis. Based on the pulsar's characteristics, its PWN is consistent with the known TeV PWNe population in the Galaxy
Multi-criteria and multi-stage environmental study of Pl@ntnet service for the year 2024
No full textIn this study, we focus our investigation on Pl@ntNet, a citizen science platform, which re- lies on Artificial Intelligence (AI) models to identify plant species. Pl@ntNet provides a large-scale infrastructure supporting millions of users in over 200 countries. At this stage of deployment, and with years of experience developing the platform, Pl@ntNet is committed to understanding the environmental impacts of its identification service and contributing to the search for reduction opportunities. Our investigations assess the associated environmental impacts of Pl@ntNet for the year 2024. We based our approach on multi-criteria LCA, considering multiple impact type and the different life-cycle phases
Performance paradox in matching systems
No full textInternational audienceIn stochastic matching systems operated under first-come–first-matched (FCFM) discipline, adding an edge to the compatibility graph may worsen the steady state performance of the system; we refer to this phenomenon as a performance paradox. We study such paradoxes on simple graphs, multigraphs with self-loops, and systems with abandonment.We consider a stochastic matching model [7] with a single global buffer. Each arriving item belongs to a class represented by a vertex of a compatibility graph. Items arrive over time according to independent Poisson processes, and wait in the buffer until they are matched or leave the system. Two items can be matched if and only if their classes are connected by an edge in the graph.Let G = (V, E) be a simple graph, where vertices represent item classes and edges represent compatibility. Under FCFM, when an item arrives, if at least one compatible item is present in the buffer, it is matched with the oldest compatible item. The two items then depart immediately. If no compatible item is available, the arrival is stored in the buffer.Assuming positive recurrence, we measure performance by the total expected backlog. On connected, nonbipartite graphs, the buffer-content process admits a closed-form stationary distribution, enabling explicit finite independent set expansions of performance metrics; see. A performance paradox occurs if, for a graph G and an added edge e under the same arrival rates μ, E[G+e,μ] > E[G,μ].This extended abstract surveys three extensions: (i) paradoxes occur on star-free graphs; (ii) the same evaluation machinery extends to multigraphs and yields paradox instances; and (iii) we show that performance paradox can also occur in systems with abandonments, for which there is no known product form solution