HAL Université de Toulouse, et Toulouse INP
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Increasing A-type CO32− substitution decreases the modulus of apatite nanocrystals
No full textInternational audienceBiological apatite mineral is highly substituted with carbonate (CO32−). CO32− can exchange for either phosphate, known as B-type, or hydroxyl groups, known as A-type. Although the former has been extensively studied, A-type CO32− substituted apatites are poorly understood. Therefore, A-type CO32− apatites with biologically relevant levels of CO32− (1.7–5.8 wt%) were prepared and characterized. The addition of A-type CO32− into the apatite structure caused the predicted expansion of the a-axis and contraction of the c-axis in the unit cell. This was accompanied by a significant modification in the atomic order, especially along the a-axis plane, and crystallite size. A combination of in situ loading with synchrotron X-ray Diffraction and Density Functional Theory showed that increasing A-type CO32− substitutions also reduced the bulk and elastic moduli of the crystals. These results show that although A-type CO32− may inhibit lattice changes caused by B-type CO32−, A-type CO32− enhances the reduction in crystal order and mineral stiffness. These results help us to identify the possible contributions of A-type CO32− substitutions in biological apatites that contain both A- and B-type CO32−. In addition, this implies that the stiffness of bioapatite may change with increasing A-type CO32− substitutions, potentially altering the fracture mechanics of calcified tissues and biomaterials
A structured group decision support approach within SMEs under industry 5.0: An application on delivery policy selection
No full textInternational audienceSmall and Medium-sized Enterprises (SMEs) have traditionally relied on top-down planning approaches such as Manufacturing Resource Planning II (MRP II), which are increasingly inadequate in addressing the dynamic and uncertain environments shaped by Industry 4.0 and 5.0. These paradigms require organizations to continuously adapt by integrating heterogeneous data, fostering collaboration, and placing humans at the centre of decision-making processes. However, current research on supporting decision-making in SMEs within these contexts remains limited. This paper proposes a structured Group Decision Support System (GDSS) tailored to SMEs, combining a Multi-Criteria Decision-Making (MCDM) approach with a simulation-based planning model. The approach enables actors from different hierarchical levels (strategic, tactical, and operational) to express preferences, compute Key Performance Indicators (KPIs), and collaboratively evaluate alternatives. The approach emphasizes transparency and coherence in decision-making while addressing individual and collective priorities. A didactic case study involving the selection of delivery policies illustrates the applicability and benefits of the proposed approach, allowing users to explore trade-offs, simulate scenarios, and converge toward a shared strategic decision
Heating-time independent densification of LATP via cold sintering process
No full textInternational audienceThe Cold Sintering Process has been used to sinter Li1.3Al0.3Ti1.7(PO4)3 powder (LATP)initially mixed with 15 wt.% of a solution of acetic acid 3M as Transient Liquid Phase(TLP). The effect of variables such as green density, heating rate, sintering temperature,dwell time and the operating pressure on the densification of LATP via CSP has beenthoroughly analysed. The operating pressure shows no effect on the green density above450 MPa. The heating rates, thus the heating time, do not modify the densificationbehavior of LATP Solid-State Electrolytes (SSEs) but a decomposition reaction takesplace at temperatures above 180 ºC. This reaction depends on the TLP amount still presentin the pores, and at higher pressures (P>450MPa) this decomposition effect ondensification is reduced as the pore volume becomes smaller. For the first time in theCSP, a linear dependence of relative density on temperature is demonstrated
Deformation and stability of a gas bubble in a biaxial straining flow
No full textTaking advantage of the recently developed L-ALE framework [Sierra-Ausin \textit{et al.}, Phys. Rev. Fluids {\bf{7}}, 113603 (2022)], we characterize the linear dynamics of an incompressible gas bubble immersed in a biaxial straining flow. We show that the system undergoes a saddle-node bifurcation with strongly different equilibrium shapes when varying the Ohnesorge number, \Oh, which compares viscous and capillary effects. Equilibrium shapes are found to be oblate for sufficiently large \Oh while, counter-intuitively, they are prolate for low-enough \Oh. The bifurcation diagram is found to contain also two sets of disconnected branches that cannot be obtained by continuation starting from a spherical shape. One set corresponds to bubble shapes expected to be unstable, while the second set comprises a wide region exhibiting stable shapes that might be observed in practice. We then characterize the linear stability of the various branches. In addition to the unstable axisymmetric mode arising at the saddle-node bifurcation, two non-oscillating drift modes are also identified, together with a new unstable non-oscillating mode with azimuthal wave number . This mode might be responsible for some type of bubble breakup observed in experiments.16 pages, 13 figure
Prevalence and factors associated with severe illness in West African children under 5 years of age detected with routine pulse oximetry in primary care
No full textInternational audienceBackground The Integrated Management of Childhood Illness (IMCI) guidelines are symptom-based algorithms used to identify critically ill children under five in primary health centres (PHC) in resource-limited countries. Hypoxaemia, a life-threatening event, is clinically underdiagnosed. The Amélioration de l'Identification des détresses Respiratoires de l'Enfant/Improving Identification of Respiratory Distress in Children (AIRE) project implemented the routine use of pulse oximetry (PO) within IMCI consultations to improve the diagnosis and management of severe hypoxaemia (pulse blood oxygen saturation <90%) at PHC level in Burkina Faso, Guinea, Mali and Niger. In this context, we measured the prevalence of severe cases and their associated social and structural factors among outpatients. Methods In 16 AIRE research PHC (4/country), all the children under five attending IMCI consultations, except those aged 2–59 months classified as simple case without cough or breathing difficulties, were eligible for the use of PO and enrolled in a cross-sectional study with parental consent. Severe IMCI+PO cases were IMCI severe cases or those with severe hypoxaemia. Results From June 2021 to June 2022, 968 neonates (0–59 days) and 14 868 children (2–59 months) were included. Prevalence of severe IMCI+PO cases was heterogeneous between countries: 5.0% in Burkina Faso, 6.1% in Niger, 18.9% in Mali and 44.6% in Guinea. Among neonates, 21.9% (95% CI 19.3 to 24.6) were severe cases versus 12.0% (95% CI 11.4 to 12.5) in older children, of which 3.3% versus 0.8%, respectively (p<0.001), had severe hypoxaemia. The adjusted social and structural factors associated with disease severity common to all four countries were as follows: age <2 months or >2 years, IMCI consultation delay >2 days, home to PHC travel time >30 min. Conclusion The prevalence of seriously ill children under five, including severe hypoxaemia, was high in PHC, particularly in neonates. The high between-country heterogeneity may be explained by differences in case definitions (Guinea) and structural factors (accessibility). Improving early access to primary care could be an actionable lever to improve the health of West African children
Non-Hermitian topology in the quantum Hall effect of graphene
No full textQuantum Hall phases have recently emerged as a platform to investigate non-Hermitian topology in condensed-matter systems. This platform is particularly interesting due to its tunability, which allows to modify the properties and topology of the investigated non-Hermitian phases by tuning external parameters of the system such as the magnetic field. Here, we show the tunability of non-Hermitian topology chirality in a graphene heterostructure using a gate voltage. By changing the charge carrier density, we unveil some novel properties specific to different quantum Hall regimes. First, we find that the best quantization of the non-Hermitian topological invariant is interestingly obtained at very high filling factor rather than on well-quantized quantum Hall plateaus. This is of particular importance for the efficient operation of devices based on non-Hermitian topology. Moreover, we observe an additional non-Hermitian topological phase in the insulating nu=0 quantum Hall plateau, which survives at lower fields than the opening of the nu=0 gap, confirming a recent prediction of a disorder-induced trivial phase. Our results evidence graphene as a promising platform for the study of non-Hermitian physics and of emergent phases in such topological devices
Temperature-dependent resonant inelastic X-ray scattering at Ni L3-Edge for NaNiO2 and LiNiO2
No full textInternational audienceLiNiO2 is a promising cathode material for Li-ion batteries, but its atomic and electronic structure is under debate. Indeed, two sets of Ni–O distances are identified from local structural probes that are related to either Jahn–Teller distortion or bond disproportionation of NiO6 octahedra. Moreover, LiNiO2 undergoes a monoclinic to rhombohedral transition at 200 K, the origin of which is still unclear. On the other hand, isostructural NaNiO2 shows differences from LiNiO2, as it is a well-known Jahn–Teller distorted system, and it undergoes a monoclinic to rhombohedral transition at 500 K associated with the loss of the Jahn–Teller distortion. To understand better these differences, we report herein Ni L3-edge resonant inelastic X-ray scattering experiments on LiNiO2 and NaNiO2 at different temperatures (25–520 K) and follow the spectral changes below and above the phase transition temperatures. The observed RIXS spectra and the mapping indicate strong spectral changes for NaNiO2, confirming the disappearance of Jahn–Teller distortion during phase transition, while the changes are minor for LiNiO2, suggesting very few modifications in the local structure. Theoretical simulations of RIXS spectra are required for further understanding; however, we believe that the reported data set can be a crucial resource for developing advanced simulations that are essential for deepening our understanding of the atomic and electronic structure of these nickelates
Modulated Ligand–Ligand Exchange Coupling and Elusive Spinmerism in a Bis(verdazyl)iron(II) Complex
No full textInternational audienc
Structure-based design, synthesis, computational screening and biological evaluation of novel pyrrole fused pyrimidine derivatives targeting InhA enzyme
No full textInternational audienceIn this study, a series of 12 novel pyrrolyl chalcones and 22 pyrrole-fused pyrimidine derivatives were synthesized with good yields. Structural characterization was performed using FT-IR, NMR, and mass spectrometry techniques. The antitubercular potential of these compounds was evaluated using the microplate alamar blue assay (MABA). Among the synthesized compounds, compound 4g exhibited the highest potency, with a minimum inhibitory concentration (MIC) of 0.78 mg mL−1 demonstrating greater efficacy than the standard drug isoniazid. Several other analogues also showed moderate to good inhibitory activity. Selected compounds were further assessed for cytotoxicity using human lung cancer (A549) and normal RAW cell lines, revealing low toxicity profiles. Enzymatic assays indicated that compound 4g achieved 36% inhibition of InhA at a concentration of 50 μM. Additionally, molecular dynamics simulations were conducted to analyze the stability of the protein–ligand complexes, suggesting that these compounds hold potential for future development as InhA inhibitors in the fight against MDR-TB
