Joseph Fourier University
Recent publications
Contrary to the first law of thermodynamics which is generally considered as easily understandable, the second law is often felt as raising conceptual difficulties. It can be noted that their usual presentation is not homogeneous, since the expressions referring to the first law are generally energy equations, while those referring to the second law are entropy equations. If we give to the second law the form of an energy equation, it seems that we are led to extend the significance of the first law. The reason is that, doing so, the change in internal energy corresponding to a given process appears to be different as we are in conditions of irreversibility or of reversibility. In thermodynamic language, this is a way to say that the equality dUirr = dUrev classically interpreted as the formulation of the first law must be substituted by the inequality dUirr > dUrev. Writing this last expression under the form dUirr = dUrev + dUadd, the question asked concerns the origin of the additional energy noted dUadd,. The suggested answer is that dUadd is a consequence of the Einstein mass-energy relation E = mc2. This would mean that the laws of thermodynamics are closely linked to the concept of relativity and that the difference dUirr - dUrev can also be formulated dUirr = dUrev - c2dm. Such an interpretation was evidently impossible for the creators of the thermodynamic theory, since relativity was unknown at that time. The aim of the present paper is to detail the reasons which lead to this hypothesis, with the hope that it can be felt as a clarification and extension of the theory.
Сверхкритический газообразный гелий при температуре 7 и 11 К возбуждался коронным разрядом при отрицательных высоких напряжениях. Разряд поддерживался электронами, созданными у катода и движущимися к аноду через плотный газ. Проведены измерения тока коронного разряда при фиксированной температуре газа с изменением его давления. При низкой плотности газа ток разряда был бо́льшим. В этом режиме электроны свободны и обладают высокой подвижностью. По мере увеличения давления ток коронного разряда резко уменьшался. При высокой плотности газа измерен слабый ток 100 нА в результате низкой подвижности электронов из-за их локализации. Такое резкое уменьшение тока разряда наблюдалось при температурах 7 и 10 К и давлениях 0.2–0.4 МПа. Были измерены и проанализированы вольт-амперные характеристики разряда. Показано, что в этих условиях подвижность электронов уменьшается на три порядка. Переход от разряда со свободными электронами в состояние с локализованными электронами происходит в сверхкритическом газе в узком диапазоне давлений и объясняется квантово-механической природой электронов.
The use of synthetic hydrogels in wastewater treatment represents a promising and scalable approach to achieving clean water. By modulation of their chemical structure, hydrogels can effectively remove a wide range of toxic compounds, including emerging organic pollutants and heavy metals. For the latter, recovery is essential for both environmental protection and metal recycling. The increasing demand for gold, a nonrenewable metal widely used in many technologies, calls for methods for its selective recovery from complex metal cation solutions. This study explores easy-to-make poly(acrylamide-co-acrylic acid) hydrogels as adsorbents for gold recovery from industrial wastewater containing other precious metals. Such material can reduce gold cations into elemental nanoparticles and microparticles in acid environments at room temperature. This process offers a potential route for metal recovery that is not based on weak interaction or complex formation. Batch tests demonstrate a good adsorption capacity (up to 124 mg/g) and efficient separation from other precious metal ions (Ru, Ir, Pd, Pt, and Rh) in a solution that closely mimics realistic industrial waste conditions. These hydrogels would enable gold recovery also from other complex metal solutions, including those derived from the dissolution of electronic wastes.
Background The newborn's intestinal microbiota can vary with gestational age. Reliable analyses of stool samples require establishing the steps of collection, packaging, transportation, and storage. Objective To describe the development of a protocol and test an algorithm for the sequence of actions and procedures for the collection, packaging, transportation, and storage of stool samples from Preterm Newborn (PTNB) admitted to a Neonatal Intensive Care Unit (NICU). Materials and methods This is a descriptive, observational study linked to a non-randomized controlled clinical trial conducted in the NICU of two public hospitals covenanted to the Unified Health System of a large city in inland northeastern Brazil. The methodology adopted in its development followed the Brazilian Ministry of Health Preparation Guide recommendations. Results The flow of actions and procedures was consistent with scientific evidence. The sequence of work process steps to implement the proposed protocol was tested and resulted in a graphical representation of an algorithm compatible with the reality of Brazilian public hospitals. Conclusion Following the protocol steps with the description of the rules of conduct and recommendations regarding the collection, packaging, transportation, and storage of stool samples from PTNBs ensured the preservation and integrity of the bacterial DNA in the stools sample. The details of the recommendations will allow their reproducibility and improvement by professionals and researchers with similar study objects. Trial registration World Health Organization (WHO) under Universal Trial Number (UTN) code U1111–1266–2295, under register RBR-3mm7cs in the Brazilian Registry of Clinical Trials (REBEC).
Soft magnetic materials, like Ni0.5Zn0.5Fe2O4, require high temperatures and regulated environments for their manufacture and processing, which can be highly energy intensive. These requirements therefore result in higher production costs and energy consumption. To address this issue, the development of composite materials based on soft magnetic ferrites has become a prominent research area. The type of particles and their size distribution, shape, and dispersion within the polymer matrix can be crucial for controlling the magnetic properties. In this context, and to reduce energy consumption, the parameters of solid-state reaction (such as calcination temperature, calcination time, and milling time) were optimized in this work to produce magnetic particles with suitable shape and size for filling a thermoplastic matrix. The impact of these parameters on phase purity, morphology, particle size, and magnetic properties was thoroughly evaluated. The results highlight that the sample synthesized at 1200 °C for 6 hours achieved an impressive saturation magnetization value of 80.07 emu g⁻¹, showcasing exceptional magnetic performance.
In this study, we investigate the impact of diamagnetic Mg substitution on the crystal, magnetic and magnetocaloric effect (MCE) properties of the novel M-type Ba0.5Ca0.5Fe12-xMgxO19 (x = 0.3, 0.4 and 0.5) BCFMO hexaferrites. The three series were synthetically prepared using the conventional solid-state process. X-ray diffraction (XRD) combined with Rietveld refinement, confirm the magnetoplumbite structure, alongside a secondary phase with space group R-3 m. The hexaplate-like grain sizes varied in the range of 2.37–1.9 µm, while the crystallite sizes are in the range of 119–104 nm. The FTIR spectra revealed two positions at 573 cm⁻¹ and 494 cm⁻¹ corresponding to the tetrahedral and octahedral sites, respectively, which confirmed the M-type hexagonal structure. The direct optical band gap energy (Eg) of BCFMO increases from 2.91 eV to 3.14 eV with varying Mg²⁺ concentration from 0.3 to 0.5. The presence of Fe in the + 3 oxidation state (Fe³⁺) and of Mg²⁺ is confirmed by XPS. The saturation magnetization Ms decreases from 111.18 to 72.34 emu/g which attributed to the addition of Mg²⁺ in Fe³⁺ in 12 k octahedral site and confirmed by DRX and XPS analyses. The increase of the coercivity HC from 3.17 kOe to 5.81 kOe is due to the reduction in crystallite sizes. The anisotropy field Ha and the effective anisotropy constant Keff rise from 12.13 to 21.78 kOe and 6.74 to 7.88 (10⁵emu/cm) for x = 0.3 to 0.5, respectively. The Para-Ferromagnetic phase transition at Curie Temperature TC was identified for all compounds. The substitution by Mg²⁺ leads to a reduction of TC from 730 to 693 K. The maximum entropy (− ΔSmmax) decreases from 1.68 to 1.29 J/kg.K, while, the relative cooling power (RCPmax) increases from 110.58 J/kg to 217.9 J/kg for x = 0.3 to 0.5, respectively at µ0H = 5 T. The results demonstrated that samples could be utilized for optoelectronic devices, permanent magnet, magnetic recording media and other magnetic applications. Graphical Abstract
Inspections of 48 photovoltaic (PV) modules within a 302.4 kWp solar array were undertaken to expose the presence of defects after 12 years of operation under the harsh environmental conditions of Djibouti. To this end, a multiple-technique testing protocol was conducted including visual inspection (VI), infrared thermography (IR), current-voltage curve characterization (I-V), ultraviolet fluorescence (UVFL) and electroluminescence imaging (EL). The main visible degradation features observed were discoloration, bubbling and snail trails with occurrences of 100%, 93.7% and 2.1% respectively. According to the IR imaging results, hotspots were observed on cells affected by snail trails. IR was combined with convolutional neural network (CNN) techniques to automatically detect the different classes of failures that PV modules may experience. EL imaging reveals that the cracks of the cells underlie the observed snail trails during visual inspection and UVFL imaging. In addition, a decrease in STC power was observed after 12 yr of operation with a median reaching 5.5% corresponding to an average degradation rate of 0.46%/years. Conclusively, fault diagnosis with combined approaches of imaging and electrical techniques is crucial to prevent defects and minimize the investment losses; this will ensure uninterrupted power generation, extended service life and high safety of photovoltaic modules.
This report explores the influence of praseodymium (Pr) doping rates on the structural, magnetic, and magnetocaloric properties of La0.67-xPrxBa0.33MnO3 (x = 0.1 and x = 0.2) manganites synthesized via the sol-gel reaction method. XRD characterization revealed the rhombohedral crystalline structure of our samples with a specific space group. Magnetic analysis demonstrated a paramagnetic-to-ferromagnetic transition in all samples, with this transition intensity increasing with higher Pr³⁺ rates. The measured magnetic isotherms M(T) allowed us to determine Curie temperatures close to TC = 318 K for x = 0.1 and TC = 297 K for x = 0.2. Furthermore, M(H) results at a 5-T field for both manganite samples (x = 0.1 and x = 0.2) indicated maximum magnetic entropy changes of 5.80 and 3.5 J·Kg⁻¹·K⁻¹, along with relative cooling powers (RCP) of 440 J·Kg⁻¹ and 280 J·Kg⁻¹, respectively. The magnetic entropy change (− ΔSM) for these transitions was simulated using a numerical method based on the Landau free energy within the mean-field approximation. The simulation results closely aligned with the experimental findings, demonstrating good agreement for these two transitions.
With the increasing demand of new magnetic materials for modern technological application alternatives to conventional magnetic materials, the development of lightweight polymer magnetic composites has become a prominent research area. For this perspective, a new magnetic material was developed using 30 wt% nickel ferrite micro and nanoparticles as fillers for a high-density polyethylene matrix. The development process began with the synthesis of NF-micro and NF-nanoparticles using solid-state and co-precipitation techniques, respectively, followed by extrusion molding and injection molding. The success of the synthesis process and the purity of the spinel structure phase were confirmed. Additionally, using the extrusion process produced polymer magnetic composite materials with a good distribution of magnetic particles within the polymer matrix, resulting in good magnetic properties and enhanced mechanical properties of the polymer magnetic materials.
The known Iπ=81+, Ex=2129−keV isomer in the semimagic nucleus Cd13082 was populated in the projectile fission of a U238 beam at the Radioactive Isotope Beam Factory at RIKEN. The high counting statistics of the accumulated data allowed us to determine the excitation energy, Ex=2001.2(7) keV, and half-life, T1/2=57(3) ns, of the Iπ=61+ state based on γγ coincidence information. Furthermore, the half-life of the 81+ state, T1/2=224(4) ns, was remeasured with high precision. The new experimental information, combined with available data for Sn134 and large-scale shell model calculations, allowed us to extract proton and neutron effective charges for Sn132, a doubly magic nucleus far-off stability. A comparison to analogous information for Sn100 provides first reliable information regarding the isospin dependence of the isoscalar and isovector effective charges in heavy nuclei.
The specification of the embryonic central nervous system (CNS) into future brain (forebrain, midbrain, or hindbrain) and spinal cord (SC) regions is a critical step of CNS development. A previous chicken embryo study indicated that anterior epiblast cells marked by Sox2 N2 enhancer activity are specified to the respective brain regions during the transition phase of the epiblast to the neural plate-forming neural primordium. The present study showed that the SC precursors positioned posterior to the hindbrain precursors in the anterior epiblast migrated posteriorly in contrast to the anterior migration of brain precursors. The anteroposterior specification of the CNS precursors occurs at an analogous time (∼E7.5) in mouse embryos, in which an anterior-to-posterior incremental gradient of Wnt signal strength was observed. To examine the possible Wnt signal contribution to the anteroposterior CNS primordium specification, we utilized mouse epiblast stem cell (EpiSC)-derived neurogenesis in culture. EpiSCs maintained in an activin- and FGF2-containing medium start neural development after the removal of activin, following a day in a transitory state. We placed activin-free EpiSCs in EGF- and FGF2-containing medium to arrest neural development and expand the cells into neural stem cells (NSCs). Simultaneously, a Wnt antagonist or agonist was added to the culture, with the anticipation that different levels of Wnt signals would act on the transitory cells to specify CNS regionality; then, the Wnt-treated cells were expanded as NSCs. Gene expression profiles of six NSC lines were analyzed using microarrays and single-cell RNA-seq. The NSC lines demonstrated anteroposterior regional specification in response to increasing Wnt signal input levels: forebrain-midbrain-, hindbrain-, cervical SC-, and thoracic SC-like lines. The regional coverage of these NSC lines had a range; for instance, the XN1 line expressed Otx2 and En2, indicating midbrain characteristics, but additionally expressed the SC-characteristic Hoxa5. The ranges in the anteroposterior specification of neural primordia may be narrowed as neural development proceeds. The thoracic SC is presumably the posterior limit of the contribution by anterior epiblast-derived neural progenitors, as the characteristics of more posterior SC regions were not displayed.
Background Young people with chronic health conditions and disabilities rely on the healthcare system to maintain their best possible health. The appropriate delivery and utilization of healthcare services are key to improve their autonomy, self-efficacy and employment outcomes. The research question of our study is directed toward investigating if poor availability and accessibility of healthcare services in general, as identified by unmet needs in healthcare, are associated with dissatisfaction with healthcare. Methods Within a European multicenter observational study, 357 young adults with cerebral palsy aged 19–28 were included. We assessed special healthcare needs, utilization of healthcare services, and satisfaction with healthcare applying the short-form of the YHC-SUN-SF, environmental and social variables (EAEQ) as well as indicators for severity of condition and functionality (e.g., GMFCS) of these participants based on a self-, assisted self- or proxy-reports. We used correlation analyses to explore associations between satisfaction with healthcare and respective indicators related to availability and accessibility of healthcare services as well as severity of the condition. In addition, we included reference values for satisfaction with heath care from young adults with various chronic conditions assessed within population-based surveys from some of the European countries included in the study. Results We identified several unmet healthcare needs, especially for widely used and established services (e.g., physical therapy). Satisfaction with healthcare (YHC-SUN-SF general and subscale scores) was moderate to high and almost consistently better for the sample of young adults with cerebral palsy as compared to reference values for young adults with various chronic conditions assessed within general population surveys). Correlation coefficients between satisfaction with healthcare and utilization of services and (unmet) healthcare needs were low, also with different indicators for severity of the condition or functionality. Conclusion Young adults with cerebral palsy reports of unmet healthcare needs varied largely but showed substantial deficits in some aspects. This seems to have no impact on the satisfaction with healthcare those patients currently receive. We conclude that these are two different constructs and somewhat independent indicators to evaluate the quality of healthcare. Clinicians and other practitioners should consider this distinction when monitoring patient needs in their daily practice.
In the field of smart mobility, Artificial Intelligence (AI) approaches are influential and can make a highly beneficial contribution. Our project aims to develop a real-time ecological map of road traffic. This map will allow electric vehicles (EVs) and thermal vehicles (TVs) to display the cost of energy consumption and CO2 emissions on different road sections. In urban environments, road traffic emissions are a significant contributor to environmental pollution, with vehicle emissions being a major component. Addressing these impacts requires a thorough understanding of the operational behavior of vehicles on different road infrastructures within the region. This paper presents a novel, comprehensive dataset, the Vehicle Activity Dataset (VAD), designed to assess the emissions and fuel consumption characteristics of vehicles about their actual operating environment. Constructed from a large number of real-world driving scenarios, VAD incorporates emission data collected by an industrial Portable Emission Measurement System (PEMS), road scenes captured by an RGB camera, and the detection of different object classes within these images. The primary objective of VAD is to provide a comprehensive understanding of the relationship between vehicle emissions and the diverse range of objects present on the road. Experimental results in real road traffic environments through different studies demonstrate the robustness of the developed dataset.
Our workshop focused on recent results in our main field (complex geometry) and its connection with other branches of mathematics. The main theme of an important proportion of the talks was Hodge theory, combined with differential-geometric methods in the study of singular spaces. One special lecture was a very comprehensive introduction in Scholze-Clausen’s theory of condensed mathematics.
We have studied the properties of the Nili Fossae olivine lithology from orbital data and in situ by the Mars 2020 rover at the Séítah unit in Jezero crater. We used the geochemistry collected by the rover’s instruments to calculate the viscosity and relative flow distance of the Séítah unit. Based on the low viscosity and distribution of the unit we postulate a ponded lava flow origin for the olivine rich unit at Séítah. We calculate an approximate depth for the cumulate layer of the lava pond based on the viscosity of the unit and model of Worster et al. (1993). We show that the resolution of orbital data is inadequate to map the phyllosilicate 2.38 μm band and demonstrate that it can be supplemented by in situ data from Mars 2020 SuperCam Laser Induced Breakdown Spectroscopy (LIBS) and reflectance observations to show that the low Al phyllosilicate in the olivine cumulate in the Séítah formation is either talc, serpentine, hectorite, Fe/Mg smectite, saponite or stevensite. We discuss two intertwining aspects of the history of the lithology: 1) the potential emplacement and properties of the cumulate layer within a ponded lava flow, using previously published models of ponded lava flows and lava lakes, and 2) the limited extent of post emplacement alteration, including phyllosilicate and carbonate alteration.
Excited levels in Kr92, Zr96, and Mo98 nuclei were reinvestigated using high-statistics multiple-γ coincidence data measured with the EXILL and FIPPS Ge arrays, following neutron-induced fission of U235 and neutron capture on a Mo97 target, respectively. The experimental goal was to search for new levels, especially with low spins, as well as to firm up spin-parity assignments to known levels. In total of 16 new levels with 64 new or corrected decays and 35 new or improved spin-parity assignments were observed in the three nuclei. We also performed large-scale shell-model calculations to learn more about the microscopic structure of levels in these nuclei. The evolution of collectivity in N=56 isotones is discussed, stressing the important role of various single-particle excitations, in particular of the πg9/2 orbital, in the shape evolution in the region.
Background: Regional changes in corticostriatal transmission induced by phasic dopaminergic signals are an essential feature of the neural network responsible for instrumental reinforcement during discovery of an action. However, the timing of signals that are thought to contribute to the induction of corticostriatal plasticity is difficult to reconcile within the framework of behavioural reinforcement learning, because the reinforcer is normally delayed relative to the selection and execution of causally-related actions. Objective: While recent studies have started to address the relevance of delayed reinforcement signals and their impact on corticostriatal processing, our objective was to establish a model in which a sensory reinforcer triggers appropriately delayed reinforcement signals relayed to the striatum via intact neuronal pathways and to investigate the effects on corticostriatal plasticity. Methods: We measured corticostriatal plasticity with electrophysiological recordings using a light flash as a natural sensory reinforcer, and pharmacological manipulations were applied in an in vivo anesthetized rat model preparation. Results: We demonstrate that the spiking of striatal neurons evoked by single-pulse stimulation of the motor cortex can be potentiated by a natural sensory reinforcer, operating through intact afferent pathways, with signal timing approximating that required for behavioural reinforcement. The pharmacological blockade of dopamine receptors attenuated the observed potentiation of corticostriatal neurotransmission. Conclusion: This novel in vivo model of corticostriatal plasticity offers a behaviourally relevant framework to address the physiological, anatomical, cellular, and molecular bases of instrumental reinforcement learning.
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Jean-Pierre Bachy
  • UFR Médecine
Sibylle Anderl
  • Institut de Planétologie et Astrophysique de Grenoble
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Grenoble, France