Hal - Université Grenoble Alpes
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Structural and Magnetocaloric Study of La0.67Sr0.33-xCaxMn1-xNixO3 (x = 0.025 and 0.05) Perovskites for Room-Temperature Magnetic Refrigeration
No full textInternational audienc
The role of hydrogen sulfide and trisulfur radical ion in molybdenum transport by hydrothermal fluids: implications for porphyry-epithermal Cu-Au-Mo deposits
No full textInternational audienceKnowledge of the chemical speciation of molybdenum in fluids under hydrothermal conditions is key to understanding the formation of porphyry Cu-Au-Mo deposits, which are the primary economic source of copper, molybdenum and rhenium. However, the chemical identity and thermodynamic stability of aqueous complexes of molybdenum and the role of different ligands on Mo metal transport yet remain inconsistent and incomplete, in particular for sulfur-bearing fluids typical of such environments. We have experimentally studied the role of hydrogen sulfide (H 2 S and HS -) and the trisulfur radical ion (S 3 •-) in the transport of molybdenum by hydrothermal fluids at 300 °C and 500 bar as a function of pH, redox conditions as well as sulfur speciation and concentration. We combined solubility measurements of molybdenite in hydrothermal reactors using fluid quenching or sampling, with in situ synchrotron X-ray absorption spectroscopy experiments and thermodynamic and molecular modeling. Our solubility and spectroscopic dataset is consistent with the formation of the tetrathiomolybdate complex, MoS 4 2-, in reduced, H 2 S/HS --dominated fluids of neutralto-alkaline pH. In contrast, a mixed-ligand complex with three sulfide ions and one trisulfur radical ion, MoS 3 (S 3 ) -, prevails in more oxidized and more acidic fluids at the sulfide-sulfate transition where S 3 •-is far more abundant. In both complexes, Mo is nominally hexavalent and in a first-shell tetrahedral coordination with sulfur atoms. The derived equilibrium constants of the formal solubility reactions (log 10 K):MoS 2(s) + 2 H 2 S 0 (aq) + 0.5 O 2(g) = MoS 4 2-+ 2 H + + H 2 O (liq) and MoS 2(s) + H 2 S 0 (aq) + S 3 •-+ 0.5 O 2(g) = MoS 3 (S 3 ) -+ H 2 O (liq) , at 300 °C and 500 bar are 0.5±0.4 and 14.6±0.4, respectively. The solubility of MoS 2(s) predicted using these constants aligns well with Mo concentrations measured in natural fluid inclusions in quartz that record S-rich fluids from porphyry-epithermal systems. In contrast, other types of Mo complexes invoked so far (molybdates, alkali ion pairs, oxy-chlorides or oxysulfides) are negligible at such conditions. Thus, trisulfur radical ion complexes may be important carriers of Mo in hydrothermal fluids and would require further systematic investigation across a wide range of temperature and pressure.</p
Exploring traditional Japanese herbal ointments for wound healing: A wide diversity of practices, metabolites, and effects
No full textInternational audienceEthnopharmacological relevance: In Kampo Japanese traditional medicine, ointments are used to treat skin wounds and promote wound healing. These ointments are prepared by extracting herbal crude drugs in sesame oil, a technique that has been practised for centuries. Their preparation varies significantly in terms of ingredients, plant species, temperature, and extraction time, leading to a wide diversity of formulations. Unlike hydrophilic plant extracts, the phytochemical composition and wound-healing efficacy of sesame oil-based herbal extractions remain largely unexplored.Objective: The objective of this study is to address this gap by focusing on lipophilic plant metabolites present in these topical formulations and to explore their potential contribution to wound healing using a keratinocyte model in vitro.Materials and methods: A survey was conducted to document Kampo ointment-related practices, focusing on highlighting variations in extraction protocols, crude drug origins, and manufacturing practices. Sample preparation excluded solid compounds from the formulations and used different solvents for the metabolomic and biological aspects. Metabolomics profiling was performed using LC-HRMS and LC-HRMS/MS to analyse the impact of different preparation temperatures and botanical sources on extract composition. In vitro assays assessed keratinocyte migration and proliferation using scratch assays and EdU (5-ethynyl-2′-deoxyuridine) incorporation and data were evaluated with appropriate statistical methods.Results: A diversity of practices concerning the Kampo ointments Shiunkō, and Shinsen taitsukō was identified. This mainly concerned the extraction temperature with three protocols: maceration (M), Low Heating (LH) and High Heating (HH). Significant differences in metabolite profiles were observed, particularly with regard to the heating temperature of the sesame oil and the origin of the crude drugs. These parameters markedly influenced the chemical composition through both the formation of transformed lipids and the degradation of bioactive compounds such as tocopherols and sterols. While the variety of sesame oils and Angelica acutiloba extracts showed no distinct biological effects on keratinocyte migration, the complete formulas Shiunkō and Shinsen taitsukō unexpectedly delayed wound closure in the model. This result is possibly due to the degradation of wound-healing metabolites and the presence of cytotoxic ones, or the inadequacy of the cell model used to evaluate these complex lipophilic preparations.Conclusion: This study highlights the diversity and complexity of traditional Kampo ointments in terms of chemical composition and, to a lesser extent, biological activity. Preparation temperature and ingredient origin
Phosphorylated lignin–cellulose nanofibrils for multifunctional PVA composites with UV-absorption and flame-retardancy
No full textInternational audienceComposite manufacturing often requires multiple additives to achieve desired properties in terms of strength, safety, and durability. Here, we produce multifunctional lignin-cellulose nanofibrils (PLCNFs) via a simple phosphorylation of giant reed using H3PO4/urea. The synergistic effects of cellulose, lignin, and phosphate in PLCNFs offer promising prospects for the manufacturing of multifunctional composites. Polyvinyl alcohol (PVA)/PLCNF nanocomposites were produced by solvent casting and comprehensively characterized using scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared (FTIR) spectroscopy, UV–vis spectroscopy, contact angle measurements, moisture uptake, and microscale combustion calorimetry. The reinforcing and flame-retardant potentials of PLCNF in the PVA matrix were revealed, along with additional UV-shielding and hydrophobicity imparted by lignin. These features highlight the potential applications of these nanocomposites as a safe substitute for flammable or hazardous materials. These multifunctional films are promising for sustainable food packaging and protective coating applications requiring UV-blocking and flame-retardant properties. In summary, this study demonstrates that underused lignocellulosic resources, when combined with benign phosphorylation chemistry, can serve as robust, reliable, and eco-friendly flame-retardant additives for enhanced nanocomposites
Secure State Estimation Algorithm for Discrete-Time Linear Systems: A Set-Valued Approach
No full textInternational audienceBased on elimination by consistency techniques, a set-valued algorithm is proposed to estimate the actual state vector of discrete-time linear systems in the presence of both bounded uncertainties and sensor anomalies. This algorithm can be considered as an extension of a former predictor-corrector set-valued state estimator to the case where the feasible domains of the bounded uncertainties are time-varying. Moreover, the introduced algorithm comprises several set-membership tests that allow detecting the occurrence of sensor faults or output malicious attacks and then discarding them from the estimation process. Moreover, to defeat the attacker’s strategy, only a sub-set of the available sensors is selected randomly at each time instant, to improve the efficiency of the estimation algorithm
Self-assembly of dextran-solanesol block copolymers into spherical micelles for photostabilization of quercetin
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Modeling of nonlinear viscoelasticity and stress softening in soft tissues
No full textInternational audienceThis paper deals with the mechanical behavior of soft living tissues under load-unload and relaxation cyclic strains. It proposes a thermodynamic model formulated within the Generalized Standard Materials framework that incorporates both Mullins’ effect and viscoelasticity, integrating the history dependent behavior of the material under finite strain. A key innovation lies in the use of a common softening function to modulate both the hyperelastic and viscous components, capturing history-dependent behavior more accurately. Viscous parameters are adjusted based on the loading history via the maximum strain invariant. Numerical implementation is validated against uniaxial tensile tests on porcine perineal tissues and a global Sobol sensitivity analysis confirms that elastic, viscous, and Mullins-related parameters are identifiable from different phases of the loading protocol. This model provides a unified, thermodynamical consistent tool for simulating soft tissue mechanics
Not on my plate! Challenges to promote meat substitutes
No full textInternational audienceWe implement an online survey on a sample of 1,088 French respondents to assess their willingness-to-pay (WTP) for meat substitutes and to test the effectiveness of informational treatments aimed at encouraging a switch to these substitutes. Using insights from the mental accounting theory, our treatments inform respondents about the carbon content of the different alternatives. We show that there is no significant difference in the WTP between the veggie and meat-like alternatives, both exceeding the WTP for cultured meat. Second, we detect weak and heterogeneous effects of our informational treatments. Third, our study emphasizes the need for careful consideration in study design, as certain results suggest that respondents’ choices may not exhibit behavioral consistency with the independence of irrelevant alternatives principle
Determining the optimal operating conditions of SOFCs electrolytes based on evolution of their electronic transport number with temperature and oxygen partial pressure: A case study of the Ce0.9Gd0.1O2-δ electrolyte
No full textInternational audienceOptimizing the performance of Solid Oxide Fuel Cells (SOFCs) or Solid Oxide Electrolysis Cells (SOECs) necessitates a thorough understanding of the electrolytes' transport properties under the device's operating conditions, whether through experimental data or established transport laws. This study investigates the electrical properties of Gd-doped ceria as a potential electrolyte material for SOFC applications. The electrical behavior of Gd-doped ceria was analyzed over a broad range of oxygen partial pressures (from 10−36 to 1 bar) and temperatures (200 °C to 900 °C) to establish the Patterson diagram, i.e., the variation of the total electrical conductivity as a function of the oxygen partial pressure (on logarithmic scales) for various temperatures. Additionally, the average transport number of the Gd-doped ceria electrolyte was evaluated under varying oxygen partial pressure gradients and temperatures using a specific semi-permeation method and compared with data derived from the Patterson diagram. The results collected in this study indicate that the use of Gd-doped ceria as an SOFC electrolyte requires precise control of oxygen partial pressure (particularly below 10−24 bar at 600 °C) or the hydrogen-to-water ratio at the hydrogen electrode to prevent efficiency degradation of the electrochemical system and to determine optimal operating conditions.</p