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Quantitative analysis of TiO2 formation on TA6V terrestrial atmospheric re-entries: Cross comparison of SEM-EDS, XRD, Raman spectroscopy and CF-LIBS measurements
No full textInternational audienceThe Ti-6Al-4V (TA6V) titanium alloy is extensively used in aerospace applications, owing to its remarkable combination of low density, high mechanical strength, and excellent oxidation resistance. Understanding its oxidation behavior is therefore essential for assessing debris survivability during terrestrial atmospheric re-entry, where the material is exposed to air plasma conditions. This paper compares complementary experimental techniques: Scanning Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy (SEM-EDS), X-ray Diffraction (XRD), Raman spectroscopy, and Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS) on a TA6V sample oxidized under conditions representative of atmospheric re-entry. Conventional analyses (SEM-EDS, XRD, Raman) consistently confirm that the predominant oxide formed is rutile TiO2 (∼6 μm thick). Spectroscopic analysis of the LIBS plasma provides complementary depth-resolved insights. Elemental profiling, which is obtained by simulating the experimental spectra using the MERLIN code, shows that the O/Ti ratio sharply decreases from a stoichiometric value towards a residual null value. Using the measured laser ablation rate, the oxide thickness is found to be consistent with the SEM observations. This work demonstrates that LIBS enables quantitative depth-resolved measurements, providing direct access to oxygen gradients and oxide stoichiometry in a single experiment
Energy-Dependent Shifts of Medium-Scale Anisotropies in Very-High-Energy Cosmic Rays Observed by LHAASO-KM2A
No full textInternational audienceSmall deviations from isotropy in the arrival directions of Galactic cosmic rays serve as a unique probe of the local magnetic environment. In this Letter, we report observations of medium-scale anisotropies (MSA) at energies above 10 TeV using the LHAASO-KM2A array. Our analysis identifies four regions of excess and four regions of deficit, each spanning angular scales of approximately ten degrees. Crucially, we detect significant energy-dependent shifts in the centroids of two excess regions: Region B and the newly identified Region . We also characterize the energy evolution of the fractional relative intensity across both excess and deficit regions. These findings imply that the observed anisotropies are shaped by the specific realization of the local turbulent magnetic field within the cosmic ray scattering length. Such energy-dependent behaviors impose strict constraints on local turbulence models and cosmic ray propagation theories
Sine-Liouville gravity as a Vertex Model on Planar Graphs
No full textInternational audienceWe investigate the universal behaviour of a one-parameter generalisation of the six-vertex model on planar graphs, which we refer to as the 7-vertex model (7vM). The 7vM is characterised by a temperature coupling and its continuum limit is characterised by a massive, dilute and dense phases similarly to the loop model. We compute the sphere and disk partition functions of the 7vM from the spectral curve of the dual matrix model, abbreviated here as 7vMM. The disk partition function for fixed length is expressed in terms of an uncharted deformation of the K-Bessel functions. We argue that 7vMM and Matrix Quantum Mechanics (MQM) provide two complementary non-perturbative realisations of sine-Liouville gravity. Specifically, we find that the continuum limit of 7vMM and the MQM share the same classical spectral curve but describe two different types of branes in sine-Liouville gravity. The 7vMM precisely covers the range of parameters where the Minkowskian MQM lacks a simple interpretation in terms of multiple tachyon scattering. We investigate the flow relating the dilute and the dense phases and argue that this flow is the gravitational analogue of the massless flow in the sine-Gordon model with imaginary mass coupling. The two extremities of the flow are described by a free boson coupled to Liouville gravity and compactified at circles with two different radii
A novel glutathione transferase harboring an FMN redox cofactor
No full textInternational audienceGlutathione transferases (GSTs) constitute a widespread superfamily of multifunctional enzymes with roles in cellular detoxification and secondary metabolism. We report that the poorly characterized Iota‐class enzymes (GSTIs) are mainly found in photosynthetic prokaryotes and eukaryotes, excluding Spermatophyta, and in a few fungi of the order Chytridiomycota. GSTIs are distinguished from other GSTs by the presence of N‐ and C‐terminal extensions of unknown function flanking the central GST domain. Focusing on the GSTI enzyme (SynGSTI1) of the model cyanobacterium Synechocystis sp. PCC 6803 ( S.6803 ), we showed that recombinant SynGSTI1 protein purified from Escherichia coli and S.6803 exhibited thiol‐transferase and dehydroascorbate reductase activities consistent with the presence of a CPYC catalytic motif in its GST domain. SynGSTI1 was found to be monomeric and to exhibit a spectrophotometric signature between 300 and 500 nm, which was attributed to a flavin mononucleotide (FMN). The C‐terminal domain of SynGSTI1 contained a conserved PRDM/L motif involved in the binding of an FMN ligand and showed a structure similar to that of the α‐subunit of phycoerythrin components of the light‐harvesting antenna of some cyanobacteria, most red algae and some cryptophytes. The deletion of the SynGSTI1 encoding gene in S.6803 (i) caused a slight decrease in the photosynthetic pigment content without impairing growth in standard photoautotrophic conditions; (ii) increased sensitivity to moderate and high light intensities; (iii) reduced glutathione levels and consistently; (iv) decreased tolerance to oxidative and metal stresses triggered by H 2 O 2 , diamide and cobalt. Thus, SynGSTI1 defines a unique GST subclass with critical roles in redox homeostasis and stress tolerance
Genomics of Long-Term Complications of Childhood Leukemia: Rationale and Design of the GenLEA Study
No full textCited by: 0International audienceBackground: Survivors of childhood acute leukemia are at risk of long-term treatment-related complications, but the role of genetic susceptibility remains unclear. We describe here the GenLEA project, which was established to investigate genetic determinants of long-term complications. Methods: GenLEA builds on the French LEA cohort, which prospectively follows acute leukemia survivors since 2004 through standardized dedicated consultations every 2 to 4 years. Patients were selected from the nested CryoLEA biobank. Cases were defined as survivors with at least one of four major complications (anthracycline-related cardiomyopathy, secondary malignant neoplasms, metabolic syndrome, or osteonecrosis) while controls were survivors without these complications, selected with the objective of a 1:3 case-to-control ratio. Genetic data were generated using genome-wide genotyping and whole-exome sequencing. Results: After quality control, 743 patients were included for analyses (241 cases and 502 controls). Fifty-one percent were male with a median age at diagnosis of 7.3 years (IQR 3.9–13.0), and median follow-up reached 14 years (IQR 7.9–19.8). Among the cases, 44 had cardiomyopathy, 50 osteonecrosis, 37 secondary malignant neoplasms, and 163 metabolic syndrome. Planned analyses include genome-wide association studies (GWAS) and downstream analyses such as transcriptome-wide association studies (TWAS) and Mendelian randomization on genotyping data, as well as gene-based tests on exome sequencing data. Perspectives: By integrating these approaches with high-quality clinical information, GenLEA offers a unique opportunity to identify molecular determinants of late complications after childhood acute leukemia. This collaborative resource will support replication efforts, meta-analyses, and ultimately the development of personalized long-term follow-up strategies. © 2026 Wiley Periodicals LLC
The quantum evolutions of the diffractive transverse-momentum dependent gluon distribution
No full textInternational audienceUsing the Colour Glass Condensate description of electron-nucleus collisions at high energy, we study the diffractive production of a pair of jets with transverse momenta much larger than the nuclear saturation momentum . At leading order in the QCD coupling, the di-jet cross-section exhibits transverse-momentum dependent (TMD) factorisation, with a gluon diffractive TMD distribution (DTMD) which is controlled by gluon saturation and describes the transverse-momentum imbalance between the produced jets. The next-to-leading corrections generate the various quantum evolutions of the diffractive gluon distribution. We focus on the Collins-Soper-Sterman (CSS) evolution which describes the change in the gluon DTMD when increasing the ''hard scale'' (the typical transverse momentum of the di-jets). We consider two different representations for this equation, one in transverse-momentum space, the other one in transverse-coordinate space. They are not fully equivalent with each other (despite being related by a Fourier transform) because of the respective boundary conditions. These conditions encode the essential physics of gluon saturation together with the effects of two other types of quantum evolution: the BK/JIMWLK evolution over the rapidity gap (''inside the Pomeron'') and the DGLAP evolution outside the rapidity gap (''within the diffractive system''). We demonstrate that, due to gluon saturation, one can compute both the boundary conditions and the CSS solutions fully from first principles, without reference to non-perturbative physics. We numerically find a good agreement between the CSS solutions in the two aforementioned representations
Noise tailoring for error mitigation and for diagnozing digital quantum computers
No full textError mitigation (EM) methods are crucial for obtaining reliable results in the realm of noisy intermediate-scale quantum (NISQ) computers, where noise significantly impacts output accuracy. Some EM protocols are particularly efficient for specific types of noise. Yet the noise in the actual hardware may not align with that. In this article, we introduce Noise Tailoring (NT) -- an innovative strategy designed to modify the structure of the noise associated with two-qubit gates through statistical sampling. We perform classical emulation of the protocol behavior and find that the NT+EM results can be up to 5 times more accurate than the results of EM alone for realistic Pauli noise acting on two-qubit gates. At the same time, on actual IBM quantum computers, the NT method falls victim to various small error sources beyond Markovian Pauli noise. We propose to use the NT method for characterizing such error sources on quantum computers in order to inform hardware development.27 pages, 16 figure
An Accurate Alternative to Hybrid Functionals for Germanium: DFT+α
No full textInternational audienceThe accuracy of bulk-property predictions in density functional theory (DFT) calculations depends on the choice of the exchange-correlation functional. While the Perdew-Burke-Ernzerhof (PBE) functional systematically overestimates lattice parameters and strongly underestimates electronic band gaps, hybrid functionals such as Heyd-Scuseria-Ernzerhof (HSE) offer better overall agreement across a broad range of materials. Using germanium as a critical test case, we challenge the ability of both functionals to capture the semiconductor properties. Although HSE improves PBE's gap error, it fails to reproduce germanium's correct Γ-L indirect and Γ-Γ band gaps simultaneously. Noting that the PBE-underestimated energy separation between the 4p valenceband maximum and 4s conduction-band minimum causes unphysical sp mixing, we propose DFT+α, a semiempirical correction scheme applied selectively to 4s-like orbitals. For germanium, DFT+α restores the proper ordering and orbital character of the band edges and yields accurate lattice constants, bulk modulus, elastic constants, and phonon frequencies at a fraction of hybrid-functional computational cost
Jeans Model for the Shapes of Self-interacting Dark Matter Halos
No full textInternational audienceThe Jeans model is a semi-analytical approach to modeling self-interacting dark matter (SIDM) that works remarkably well to reproduce the spherically-averaged halo profiles from observations and simulations of relaxed galaxies and galaxy clusters. However, SIDM halos are not spherically symmetric in general since they respond to nonspherical baryon distributions and retain nonsphericity from their initial collapse. In this work, we generalize the Jeans model to describe SIDM density profiles and halo shapes beyond spherical symmetry. Observational tests via halo shapes are especially important for testing SIDM in massive galaxies, M_{\rm 200} \sim 10^{12} - 10^{13} \; \Msun, where SIDM and collisionless dark matter halos can have indistinguishable spherically-averaged profiles but distinct halo shapes. We validate our model by comparing to cosmological simulations with baryons for both SIDM with \sigmam = 1 \cmg and collisionless cold dark matter. Our approach differs from previous work in this direction, taking into account the fact that multiple scatterings are required to impact the shape of the halo, as well as being computationally inexpensive to implement. The nonspherical Jeans model can be used in conjunction with halo shape observations (e.g., from gravitational lensing or X-ray data) to directly constrain dark matter self-interactions