1,344 results on '"Physique"'
Search Results
2. Helping Osteoarthritis Patients to Walk With NSAID (PERIPATEI)
- Author
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Plateforme d'Investigation Clinique, INSERM CIC1405, CHU de Clermont-Ferrand, France, Fondation Apicil, Médecine Physique et Réadaptation, CHU de Clermont-Ferrand, France, Médecine du Sport et Explorations Fonctionnelles, CHU de Clermont-Ferrand, France, Rhumatologie, CHU de Clermont-Ferrand, France, Direction de la Recherche Clinique et des Innovations, CHU de Clermont-Ferrand, France, SARL BOUCHARENC, Saint-Chély d'Apcher, France, Inserm U1107 ' Neuro-Dol ', Clermont-Ferrand, France, and Université Clermont-Auvergne, France
- Published
- 2024
3. Combination of Neck Muscle Vibration and tDCS With Conventional Rehabilitation in Neglect Patients (HEMISTIM)
- Author
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Université de Lorraine, DevAH (EA3450), Nancy, France, Union de Gestion des Etablissements des Caisses d'Assurance Maladie - PACA, and Institut Régional de Médecine Physique et de Réadaptation de Nancy - Etablissement de Lay Saint Christophe
- Published
- 2024
4. CFD calculation of a phase change material using STAR-CCM+ for a passive safety system of a sodium-cooled fast reactor
- Author
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Universitat Politècnica de Catalunya. Departament de Física, École nationale supérieure de physique, électronique et matériaux, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Batet Miracle, Lluís, Li, Simon, Pantano, Alessandro, Meston, Ria, Universitat Politècnica de Catalunya. Departament de Física, École nationale supérieure de physique, électronique et matériaux, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Batet Miracle, Lluís, Li, Simon, Pantano, Alessandro, and Meston, Ria
- Abstract
The aim of the present study is to quantify the impact that local scale physics of phase change has on the overall heat transfer of the quasi-cubic modular element of an innovative Decay Heat Removal System (DHRS). To evaluate the capabilities of using a solid/liquid phase change material (PCM) to drive passive natural circulation to cool the core of a Sodium-cooled Fast Reactor (SFR), a CFD analysis was carried out using STAR-CCM+. The melting-solidification model that utilizes the Volume- Of-Fluid (VOF) enthalpy-porosity approach proved sufficient when liquid and solid phases are isotropic, homogeneous and remain in thermal equilibrium at the interface, however, demonstrated extreme sensitivity when considering variable density between the phases. A preliminary estimation for the placement of the thermocouples according to the calculations was made for a future experimental study of melting Zamak PCM to measure areas of highly convective motion, hot and cold spots, and the shape of the melting interface
- Published
- 2024
5. New type of filaments for improved accuracy of multiple sulfur isotope analyses by electron-impact gas-source mass spectrometry.
- Author
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Cartigny P, Bouyon A, Bars H, Albrecht N, Kohl IE, Landais G, Duverger A, and Farquhar J
- Abstract
Rationale: The analysis of the three sulfur stable isotope ratios (
33 S/32 S,34 S/32 S,36 S/32 S) is routinely performed by gas-source isotope ratio mass spectrometry (IRMS) on the SF6 gaseous molecule, collecting SF5 + ions at m/z ~ 127, 128, 129 and 131. High precision and accuracy are commonly achieved owing to a lack of correction because fluorine has only one isotope and the inert nature of the SF6 molecule. The analysis of the36 S/32 S ratio is, however, complicated by the low abundance of36 S (~0.015%) and the possible occurrence of trace amounts of fluorocarbon compounds leading to12 C3 F5 + ions at m/z ~ 131, i.e. where36 SF5 + ions are collected., Methods: We used gas-source high-resolution IRMS to better characterize the nature of possible interferences, and we tested novel types of filaments in order to investigate their influence on possible interferences., Results: We confirm that the12 C3 F5 + ion represents the main isobaric interference at m/z ~ 131. We also demonstrate that tungsten fluoride adducts are formed from the reaction of fluorine ions derived during fragmentation of the SF6 molecule with the hot tungsten filament. These reactions lead to the formation of e.g. WF5 + , WF4 + , WF3 + ions, including doubly charged ions. WF4 ++ , in particular, leads to isobaric interference on m/z ~ 128, 129 and 131 from180 WF4 ++ ,182 WF4 ++ and186 WF4 ++ ions, respectively. Because180 W (0.12%) is at low abundance, its influence on δ33 S measurements would remain negligible, but182 W (26.5%) and186 W (28.4%) lead to scale contraction for both δ34 S and δ36 S., Conclusions: Rather than correcting for these interferences, or working at high mass resolution, we suggest avoiding W isobaric interferences by using other types of filaments, with initial reports on both pure Re filaments and Y2 O3 -coated W filaments., (© 2024 John Wiley & Sons Ltd.)- Published
- 2024
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6. Characterization of PM 2.5 emissions from on-road vehicles in the tunnel of a major Middle Eastern city.
- Author
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Fakhri N, Fadel M, Abdallah C, Karam C, Iakovides M, Oikonomou K, Formenti P, Doussin JF, Borbon A, Sciare J, Hayes PL, and Afif C
- Subjects
- Lebanon, Air Pollution statistics & numerical data, Particle Size, Polycyclic Aromatic Hydrocarbons analysis, Particulate Matter analysis, Vehicle Emissions analysis, Air Pollutants analysis, Environmental Monitoring methods, Cities
- Abstract
Traffic emissions are an important source of air pollution worldwide, but in the Middle East, this problem is exacerbated by weak or no enforcement of emission regulations. Comprehensive measurements of fine PM emission factors (EFs) from road transport in the region have not yet been conducted, but such data are necessary for quantitative assessments of the health impact of transport emissions in the region. To address this need, PM
2.5 samples collected inside the Salim Slam tunnel in Beirut, Lebanon were analyzed for carbonaceous matter (organic carbon (OC) and elemental carbon (EC)), water-soluble ions, elements, and selected organic compounds. The OC/EC ratio was 1.8 for the total fleet and 2.6 for light-duty vehicles (LDV), in agreement with the dominant proportion of gasoline LDV in the Lebanese fleet. A Cu/Sb ratio of 4.2 ± 0.1 was observed, offering a valuable metric for detecting brake wear emissions in subsequent studies conducted in the region. The EFs of carbonaceous matter, elements and ions generally varied by a factor 0.1 and 10 in comparison to literature values, while those for alkanes and polycyclic aromatic hydrocarbons were similar to the upper values previously reported. The average number size distribution was characterized by a single mode around 35 nm. The particles number EF (for diameters between 10 and 480 nm) was within the range of 1014 -1015 particles per kg of fuel. The chemical mass balance model showed an average contribution to EF of 62% from non-exhaust sources. This study highlights the need for more enforceable stringent vehicular regulations because of the local practices (i.e., removal of catalyst) and some EF values are very high compared to other studies/countries., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)- Published
- 2024
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7. Statistical mechanics of crystal nuclei of hard spheres.
- Author
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de Jager M, Vega C, Montero de Hijes P, Smallenburg F, and Filion L
- Abstract
In the study of crystal nucleation via computer simulations, hard spheres are arguably the most extensively explored model system. Nonetheless, even in this simple model system, the complex thermodynamics of crystal nuclei can sometimes give rise to counterintuitive results, such as the recent observation that the pressure inside a critical nucleus is lower than that of the surrounding fluid, seemingly clashing with the strictly positive Young-Laplace pressure we would expect in liquid droplets. Here, we re-derive many of the founding equations associated with crystal nucleation and use the hard-sphere model to demonstrate how they give rise to this negative pressure difference. We exploit the fact that, in the canonical ensemble, a nucleus can be in a (meta)stable equilibrium with the fluid and measure the surface stress for both flat and curved interfaces. Additionally, we explain the effect of defects on the chemical potential inside the crystal nucleus. Finally, we present a simple, fitted thermodynamic model to capture the properties of the nucleus, including the work required to form critical nuclei., (© 2024 Author(s). Published under an exclusive license by AIP Publishing.)
- Published
- 2024
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8. Atomistic insights into the nucleation and growth of hexagonal boron nitride and graphene heterostructures.
- Author
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Achehboune M, Zhour K, Dabrowski J, Vignaud D, Franck M, Lukosius M, Colomer JF, and Henrard L
- Abstract
Graphene and hexagonal boron nitride (hBN) are two-dimensional (2D) materials with a similar atomic structure but drastically different although complementary electronic properties. The large-scale synthesis of h-BN/graphene heterostructures with high crystallographic quality is required to fully benefit of the graphene electronic properties. In this study, we examine numerically the interaction of graphene precursors on hBN and of hBN precursors on graphene to gain deep insight of the CVD and MBE growth mechanism of graphene/hBN heterostructures. Density functional theory (DFT) calculations reveal the adsorption and diffusion behaviors for B, N, and C atoms on these surfaces. In particular, the adsorption energy is found to be similar to the diffusion barriers, except for the nearly free diffusion of B atoms on both graphene and hBN. We have also investigated the transition from individual atoms to graphene or h-BN seeds by considering the stability of linear chains as well as branched and ring seeds. Furthermore, for larger clusters, the triangular h-BN domains are found to be equally thermodynamically stable on graphene regardless of their orientation. These findings provide preliminary hints for the ability of graphene to grow on hBN layers and hBN layer on graphene.
- Published
- 2024
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9. Self-Assembly of Chiral Ligands on 2D Semiconductor Nanoplatelets for High Circular Dichroism.
- Author
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Lehouelleur H, Po H, Makké L, Fu N, Curti L, Dabard C, Roux-Byl C, Baptiste B, Van Zee NJ, Pons T, Lhuillier E, Li J, and Ithurria S
- Abstract
Group II-VI semiconductor nanoplatelets (NPLs) with atomically defined thicknesses and extended atomically flat (001) facets are used for ligand binding and chiro-optical effects. In this study, we demonstrate that tartrate ligands, anchored by two carboxylate groups, chelate the (001) facets of NPLs at an average ratio of one tartrate molecule to two cadmium (Cd) surface atoms. This assembly of chiral molecules on inorganic nanocrystals generates a circular dichroism g -factor as high as 1.3 × 10
-2 at the first excitonic transition wavelength of NPLs. Tartrate ligands induce an orthorhombic distortion of the initially "cubic" crystal structure, classifying the NPLs within the 222-point group. Unlike spherical nanocrystals, where it is difficult to discern whether chiral ligands affect only the surface atoms or the entire crystal structure, our findings unequivocally show that the crystal structure of NPLs is modified due to their thinness and atomically precise thickness. The in-plane lattice parameters experience compressive and tensile stresses, significantly splitting the heavy-hole and light-hole bands. Additionally, tartrate ligands adopt different conformations on the NPL surface over time, resulting in dynamic changes in the circular dichroism signal, including an inversion of its sign.- Published
- 2024
- Full Text
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10. Structural Manipulation of Spin Excitations in a Molecular Junction.
- Author
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Kögler M, Néel N, Limot L, and Kröger J
- Abstract
Single metallocene molecules act as sensitive spin detectors when decorating the probe of a scanning tunneling microscope (STM). However, the impact of the atomic-scale electrode details on the molecular spin state has remained elusive to date. Here, a nickelocene (Nc) STM junction is manipulated in an atomwise manner showing clearly the dependence of the spin excitation spectrum on the anchoring of Nc to Cu(111), a Cu monomer, and trimer. Moreover, while the spin state of the same Nc tip is a triplet with tunable spin excitation energies upon contacting the surface, it transitions to a Kondo-screened doublet on a Cu atom. Notably, the nontrivial magnetic exchange interaction of the molecular spin with the electron continuum of the substrate determines the spectral line shape of the spin excitations.
- Published
- 2024
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11. Drop deformation in a planar elongational flow: impact of surfactant dynamics.
- Author
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Wailliez J, Regazzi P, Salonen A, Chen PG, Jaeger M, Leonetti M, and Rio E
- Abstract
Drops in extensional flow undergo a deformation, which is primarily fixed by a balance between their surface tension and the viscous stress. This deformation, predicted and measured by Taylor on millimetric drops, is expected to be affected by the presence of surfactants but has never been measured systematically. We provide a controlled experiment allowing us to measure this deformation as a function of the drop size and of the shear stress for different surfactants at varying concentrations. Our observation is that the deformation predicted by Taylor is recovered at zero and high surfactant concentration, whereas it is smaller at concentrations close to the critical micellar concentration. This is in contradiction to the existing analytical models. We develop a new analytical model, taking into account the surfactant dynamics. The model predicts a transition between a deformation similar to that of a pure liquid and a smaller one. We show that the transition is driven by a parameter K
L , which compares adsorption and desorption dynamics. Finally, the concentration C *, at which we observe this transition in the extensional flow is in good agreement with the one predicted by independent measurements of KL .- Published
- 2024
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12. Long range signature of liquid's inertia in nanoscale drainage flows.
- Author
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Bigan N, Lizée M, Pascual M, Niguès A, Bocquet L, and Siria A
- Abstract
In confinement, liquid flows are governed by a complex interplay of molecular, viscous and elastic forces. When a fluid is confined between two approaching surfaces, a transition is generally observed from a long range dynamical response dominated by viscous forces in the fluid to a short range elasto-hydrodynamic response due to the elastic deformation of the solid materials. This study investigates the behavior of fluids driven between oscillating solid surfaces using a dynamic Surface Force Apparatus. Our findings reveal that the dominant influence on fluid behavior arises from long-range inertial effects, superseding conventional elasto-hydrodynamic effects. Through systematic experimentation involving fluids of varied viscosities, diverse substrates, we identify key parameters and develop a comprehensive model which explains our measurements. Our findings not only provide insights into confined fluid dynamics but also offer practical implications for various applications in microfluidics, nanotechnology and liquid lubrication.
- Published
- 2024
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13. Defects or no defects? Or how to design 20-25 nm spherical iron oxide nanoparticles to harness both magnetic hyperthermia and photothermia.
- Author
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Freis B, Kiefer C, Ramirez MLA, Harlepp S, Mertz D, Pichon B, Iacovita C, Laurent S, and Begin S
- Subjects
- Humans, Photothermal Therapy, Phototherapy, Particle Size, Ferric Compounds chemistry, Hyperthermia, Induced methods, Magnetic Iron Oxide Nanoparticles chemistry
- Abstract
Designing iron oxide nanoparticles (IONPs) to effectively combine magnetic hyperthermia (MH) and photothermia (PTT) in one IONP formulation presents a significant challenge to ensure a multimodal therapy allowing the adaptation of the treatment to each patient. Recent research has highlighted the influence of factors such as the size, shape, and amount of defects on both therapeutic approaches. In this study, 20-25 nm spherical IONPs with a spinel composition were synthesized by adapting the protocol of the thermal decomposition method to control the amount of defects. By tuning different synthesis parameters such as the precursor nature, the introduction of a well-known oxidizing agent, dibenzylether (DBE), in the reaction medium, the heating rate and duration and the introduction of a nucleation step, we thus established two different synthesis protocols, one involving the use of a small amount of DBE leading to IONPs with only a few defects and another that took an optimized route to oxidize the wüstite nuclei during the IONP growth and led to IONPs exhibiting more structural and oxygen defects. IONPs exhibiting fewer defects showed enhanced MH and PTT heating values even when immobilized in a matrix, despite a decrease in MH heating values showing that they release mainly heat through the Brownian mechanism. These MH measurements have also confirmed that defects play a key role in enhancing Néel relaxation. PTT measurements demonstrated higher heating values with IONPs with fewer defects and a correlation between Urbach energy and SAR values suggesting an impact of vacancy defects on PTT performances. Therefore, IONPs exhibiting fewer defects under our synthesis conditions appear as suitable IONPs to combine both MH and PTT treatments with high performances. These findings pave the way for promising applications in combined therapies for cancer treatment.
- Published
- 2024
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14. Deep mantle plumes feeding periodic alignments of asthenospheric fingers beneath the central and southern Atlantic Ocean.
- Author
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Munch FD, Romanowicz B, Mukhopadhyay S, and Rudolph ML
- Abstract
High-resolution full waveform seismic tomography of the Earth's mantle beneath the south and central Atlantic Ocean brings into focus a series of asthenospheric low shear velocity channels, or "fingers" on both sides of the southern and central mid-Atlantic ridge (MAR), elongated in the direction of absolute plate motion with a spacing of [Formula: see text]1,800 to 2,000 km, and associated with bands of shallower residual seafloor depth anomalies that suggest channeled flow over thousands of kilometers. Each of the three most clearly resolved fingers on the African side of the MAR corresponds to a separate group of whole mantle plumes rooted in distinct patches at the core-mantle boundary, feeding hotspots, and volcanic lines with distinct isotopic signatures. Plumes of a given group appear to merge at the top of the lower mantle before separating again, suggesting interaction of deep mantle flow with a more vigorous mesoscale circulation in the upper mantle. The corresponding hotspots are generally offset from the location of the deep mantle plume roots. The distinct isotopic signatures of these hotspot groups are also detected in the mid-ocean ridge basalts at the location where the fingers meet the ridge. Meanwhile, at least some of the variability within each plume group could originate in the upper mantle and extended transition zone where plumes in a given group appear to merge and pond. This study also adds to mounting evidence that the African large low shear velocity province is not a uniform, unbroken pile of dense material rising high above the core-mantle boundary, but rather a collection of mantle plumes rooted in patches of distinct composition., Competing Interests: Competing interests statement:The authors declare no competing interest.
- Published
- 2024
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15. Coalescence Frequency in O/W Emulsions: Comparisons of Experiments with Models.
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Pessanha TM, Varade S, Salonen A, and Langevin D
- Abstract
We have studied the coalescence of oil in water emulsions under the influence of gravity. The emulsions were made with alkane oils and surfactants with varying physical chemistry. We chose cationic alkyl trimethylammonium bromides of different chain lengths and nonionic surfactants of ethylene oxide and sugar head groups, including polymeric surfactants. We observed phase separation in two steps. Creaming of the oil drops is followed by their rapid coalescence, increasing the average drop size and resulting in complete surfactant surface coverage of the interfaces. Full phase separation occurs after much longer times T
c when the emulsion drops coalesce dramatically. We have used a model by Dinh et al. to relate Tc to the coalescence frequency and hence to the activation energy for the rupture of the films between two neighboring drops. Our results support the view that the coalescence of stable emulsions (stable at least for a few hours) is a thermally activated process and is controlled by the surface compression elastic modulus. This modulus was determined using surface tension measurements and calculations using the Gibbs adsorption equation. The observed differences between ionic and nonionic systems are attributed to a two-step film rupture process in the case of ionic surfactants, which is not found in nonionic systems.- Published
- 2024
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16. Photothermal AFM-IR Depth Sensitivity: An Original Pathway to Tomographic Reconstruction.
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Dazzi A, Mathurin J, Leclere P, Nickmilder P, De Wolf P, Wagner M, Hu Q, and Deniset-Besseau A
- Abstract
Photothermal atomic force microscopy-infrared (AFM-IR) enables label-free chemical imaging and spectroscopy with nanometer-scale spatial resolution through the integration of atomic force microscopy (AFM) and infrared radiation. The capability for subsurface and three-dimensional (3D) tomographic material analysis remains, however, largely unexplored. Here, we establish a simple and robust empirical relationship between the probing depth and laser repetition rate for three important modes of AFM-IR operation: resonance-enhanced, tapping, and surface-sensitive AFM-IR. Using this empirical relationship, we demonstrate, based on the example of resonance-enhanced operation, how photothermal AFM-IR of thin surface/subsurface layers of polystyrene domains in the poly(methyl methacrylate) matrix can result in 3D representations revealing the size and thickness of small polystyrene domains in the poly(methyl methacrylate) matrix with nanometer-scale resolution. Experimental findings are confirmed by analytical models.
- Published
- 2024
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17. Ultra-low noise measurements of ionic transport within individual single-walled carbon nanotubes.
- Author
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Bsawmaii L, Delacou C, Kotok V, Méance S, Saada K, Kribeche MA, Tahir S, Roblin C, Louiset A, Okuno H, Manghi M, Palmeri J, Henn F, Noury A, and Jourdain V
- Abstract
Despite 15 years of extensive investigation, the fabrication and study of nanofluidic devices that incorporate a single carbon nanotube (CNT) still represents a remarkable experimental challenge. In this study, we present the fabrication of nanofluidic devices that integrate an individual single-walled CNT (SWCNT), showcasing a notable reduction in noise by 1-3 orders of magnitude compared to conventional devices. This achievement was made possible by employing high dielectric constant materials for both the substrate and the CNT-covering layer. Furthermore, we provide a detailed account of the crucial factors contributing to the successful fabrication of SWCNT-based nanofluidic devices that are reliably leak-free, plug-free, and long-lived. Key considerations include the quality of the substrate-layer interface, the nanotube opening, and the effective removal of photoresist residues and trapped microbubbles. We demonstrate that these devices, characterized by a high signal-to-noise ratio, enable spectral noise analysis of ionic transport through an individual SWCNT, thus showing that SWCNTs obey Hooge's law in 1/ f at low frequencies. Beyond advancing our fundamental understanding of ion transport in SWCNTs, these ultralow-noise measurements open avenues for leveraging SWCNTs in nanopore sensing applications for single-molecule detection, offering high sensitivity and identification capabilities.
- Published
- 2024
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18. Harnessing coupled nanolasers near exceptional points for directional emission.
- Author
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Madiot G, Chateiller Q, Bazin A, Loren P, Pantzas K, Beaudoin G, Sagnes I, and Raineri F
- Abstract
Tailoring the losses of optical systems within the frame of non-Hermitian physics has appeared very fruitful in the past few years. In particular, the description of exceptional points (EPs) with coupled resonators has become widespread. The on-chip realization of these functionalities is crucial for integrated nanophotonics but requires fine control techniques of the nanodevice properties. Here, we demonstrate pump-controlled directional emission of two coupled nanolasers that distantly interact via an integrated waveguide. This coupling scheme unusually enables both frequency and loss couplings between two cavities, which can be advantageously exploited to reach EPs by either detuning the cavities or controlling the gain of nanolasers. The system can be readily reconfigured from bidirectional to unidirectional emission by adjusting the pump power.
- Published
- 2024
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19. Septic Shock Requiring Three Vasopressors: Patient Demographics and Outcomes.
- Author
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Kwak GH, Madushani RWMA, Adhikari L, Yan AY, Rosenthal ES, Sebbane K, Yanes Z, Restrepo D, Wong A, Celi LA, and Kistler EA
- Subjects
- Humans, Male, Female, Aged, Retrospective Studies, Middle Aged, Intensive Care Units, Cohort Studies, Aged, 80 and over, Demography, Shock, Septic drug therapy, Shock, Septic mortality, Vasoconstrictor Agents therapeutic use, Hospital Mortality
- Abstract
Objectives: Septic shock is a common condition necessitating timely management including hemodynamic support with vasopressors. Despite the high prevalence and mortality, there is limited data characterizing patients who require three or more vasopressors. We sought to define the demographics, outcomes, and prognostic determinants associated with septic shock requiring three or more vasopressors., Design: This is a multicenter retrospective cohort of two ICU databases, Medical Information Mart for Intensive Care IV (MIMIC-IV) and electronic ICU-Clinical Research Database, which include over 400,000 patients admitted to 342 ICUs., Patients: Inclusion criteria entailed patients who were: 1) age 18 years old and older, 2) admitted to any ICU, 3) administered at least three vasopressors for at least 2 hours at any time during their ICU stay, and 4) identified to have sepsis based on the Sepsis-3 criteria., Interventions: None., Measurements and Main Results: A total of 3447 patients met inclusion criteria. The median age was 67 years, 60.5% were male, and 96.6% had full code orders at the time of the third vasopressor initiation. Septic shock requiring three or more vasopressors was associated with 57.6% in-hospital mortality. Code status changes occurred in 23.9% of patients following initiation of a third vasopressor. Elevated lactate upon ICU admission (odds ratio [95% CI], 2.79 [2.73-2.85]), increased duration of time between ICU admission and third vasopressor initiation (1.78 [1.69-1.87]), increased serum creatinine (1.61 [1.59-1.62]), and age above 60 years (1.47 [1.41-1.54]) were independently associated with an increased risk of mortality based on analysis of the MIMIC-IV database. Non-White race and Richmond Agitation-Sedation Scale scores were not associated with mortality., Conclusions: Septic shock requiring three vasopressors is associated with exceptionally high mortality. Knowledge of patients at highest risk of mortality in this population may inform management and expectations conveyed in shared decision-making., Competing Interests: The authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2024 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the Society of Critical Care Medicine.)
- Published
- 2024
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20. Preventing the impact of solute adsorption in Taylor dispersion analysis: Application to protein and lipid nanoparticle analysis.
- Author
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Roca S, Leclercq L, Biron JP, Martin M, and Cottet H
- Subjects
- Adsorption, Proteins chemistry, Hydrodynamics, Diffusion, Lipids chemistry, Reproducibility of Results, Liposomes, Nanoparticles chemistry
- Abstract
Taylor Dispersion Analysis (TDA) allows diffusion coefficient (D) or hydrodynamic radius (R
h ) determination on a wide range of size between angstroms and about 300 nm. However, solute adsorption phenomena can affect the repeatability and reproducibility of TDA. Several numerical studies addressed the theoretical impact of solute adsorption in TDA, but very few experimental studies focus on this topic and no experimental methodologies were proposed so far to reduce the impact of adsorption in TDA. In this work, an experimental protocol, called plug-in-front TDA, consisting of adding the solute in the eluent at a lower concentration compared to the injected sample, was proposed to strongly limit the impact of adsorption on the Rh determination. This protocol was suggested based on the evidence that adsorption / desorption phenomena impacting narrow bore fused silica TDA in aqueous conditions are typically slow processes that can be counteracted by saturating the interaction sites during the experiments. Successful applications to proteins and mRNA lipid nanoparticles (LNP) in vaccine against Covid 19 and protein analysis were reported. TDA of proteins in conditions of strong interactions with the capillary surface was possible using the plug-in-front methodology. We anticipate that such experimental methodology will greatly help the experimentalist for implementing TDA in various applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)- Published
- 2024
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21. Interatomic and intermolecular decay processes in quantum fluid clusters.
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LaForge AC, Ben Ltaief L, Krishnan S, Sisourat N, and Mudrich M
- Abstract
In this comprehensive review, we explore interatomic and intermolecular correlated electronic decay phenomena observed in superfluid helium nanodroplets subjected to extreme ultraviolet (XUV) radiation. Helium nanodroplets, known for their distinctive electronic and quantum fluid properties, provide an ideal environment for examining a variety of non-local electronic decay processes involving the transfer of energy, charge, or both between neighboring sites and resulting in ionization and the emission of low-kinetic energy electrons. Key processes include interatomic or intermolecular Coulombic decay (ICD) and its variants, such as electron transfer-mediated decay (ETMD). Insights gained from studying these light-matter interactions in helium nanodroplets enhance our understanding of the effects of ionizing radiation on other condensed-phase systems, including biological matter. We also emphasize the advanced experimental and computational techniques that make it possible to resolve electronic decay processes with high spectral and temporal precision. Utilizing ultrashort pulses from free-electron lasers, the temporal evolution of these processes can be
followed, significantly advancing our comprehension of the dynamics within quantum fluid clusters and non-local electronic interactions in nanoscale systems., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)
- Published
- 2024
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22. Interatomic Coulombic electron capture beyond the virtual photon approximation.
- Author
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Šenk J, Graves V, Gorfinkiel JD, Kolorenč P, and Sisourat N
- Abstract
Via the interatomic Coulombic electron capture (ICEC) process, an electron can be captured by an atom or a molecule, while the binding and excess energy is transferred, via a long-range Coulomb interaction, to a neighboring atom or molecule. The transferred energy can be used to ionize or electronically excite the neighboring species. When the two species are asymptotically far apart, an analytical formula for the ICEC cross sections can be derived. The latter can then be estimated using only the energies and the photoionization cross sections of each species. In this work, we develop an analytical model that allows us to predict the ICEC cross sections when the size of the involved species is comparable to the distance between the two entities. Using ab initio R-matrix results for various systems, we show that the new model reduces the error of the asymptotic formula by two orders of magnitude on average while only using parameters that can be taken from the properties of each species., (© 2024 Author(s). Published under an exclusive license by AIP Publishing.)
- Published
- 2024
- Full Text
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23. Microscopic Structure of Neat Linear Alkylamine Liquids: An X-Ray Scattering and Computer Simulation Study.
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Požar M, Friedrich L, Millet T, Paulus M, Sternemann C, and Perera A
- Abstract
Linear amines, from propylamine to nonylamine, are studied under ambient conditions by X-ray scattering and molecular dynamics simulations of various force field models. The major finding is that the prepeak in alkylamines is about 1 order of magnitude weaker than that in alkanols, hence suggesting much weaker hydrogen bonding-induced clustering of the amine groups than for the hydroxyl groups. Computer simulation studies reveal that the OPLS-UA model reproduces the prepeak, but with larger amplitudes, while the GROMOS-UA and CHARMM-AA force fields show almost no prepeak. Simulations of all models show the existence of hydrogen-bonded clusters, equally confirmed by the prominent prepeak of the structure factor between the nitrogen atoms. The hydrogen bond strength, as modeled by the Coulomb association in classical force field models, is about the same order of magnitude for both systems. Then, one may ask what is the origin of the weaker prepeak in alkylamines? Simulation data reveal that the existence of the prepeak is controlled through the cancellation of the positive contributions from the charged group correlations by the negative contributions from the cross charged-uncharged correlations. The C
2v symmetry of the amine headgroup hinders clustering, which favors cross correlations with the tail atoms. This is opposite to alkanols where the symmetry of the hydroxyl headgroup favors clustering and hinders cross correlations with the alkyl tail. This competition between charged and uncharged atomic groups appears as a general mechanism to explain the existence of scattering prepeaks, including their position and amplitude.- Published
- 2024
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24. Morphology-electronic effects in ultra-model nanocatalysts under the CO oxidation reaction: the case of ZnO ultrathin films grown on Pt(111).
- Author
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Liu H, Zhang L, Lebègue S, Bournel F, Gallet JJ, and Naitabdi A
- Abstract
The study of the surface morphology and interface of metal-oxides is crucial for understanding the behavior of these model systems as nanocatalysts. Besides, understanding the interplay between morphology, stability, and reactivity is crucial for designing efficient catalysts. Here, we investigated the stability and dewetting of ZnO ultrathin films on Pt(111) under CO oxidation conditions. For films <1 monolayer (ML), CO-induced dewetting occurs at the metal-oxide interface or defects. The morphology, dependent on thickness, influences reactivity. (6 × 6) structures show greater CO binding and structural changes compared to (4 × 4) structures, which exhibit resilience due to Zn-OH formation. ZnO electronic properties, as revealed by Auger spectroscopy and scanning tunneling spectroscopy (STS) investigations, vary with thickness. Low-thickness films [<2 monolayers (ML)] exhibit metallic-like behavior, possibly due to Zn-Pt interaction, while thicker films show n-type semiconductor behavior with a bandgap opening ( E
BG = 0.9 eV at 2 ML). DFT calculations of the local density of states (LDOS) as a function of ZnO thickness confirm the thickness-dependent electronic structure, with 0.3 ML films having a higher LDOS near the Fermi level than 1 ML films. These findings highlight the critical role of ZnO morphology in determining its stability and reactivity which opens up avenues for designing efficient and more stable ZnO-based nanocatalysts for a wide range of chemical reactions, including CO oxidation and CO2 hydrogenation.- Published
- 2024
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25. Surface accumulation and acid-base equilibrium of phenol at the liquid-vapor interface.
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Richter C, Dupuy R, Trinter F, Buttersack T, Cablitz L, Gholami S, Stemer D, Nicolas C, Seidel R, Winter B, and Bluhm H
- Abstract
We have investigated the surfactant properties of phenol in aqueous solution as a function of pH and bulk concentration using liquid-jet photoelectron spectroscopy (LJ-PES) and surface tension measurements. The emphasis of this work is on the determination of the Gibbs free energy of adsorption and surface excess of phenol and its conjugate base phenolate at the bulk p K
a (9.99), which can be determined for each species using photoelectron spectroscopy. These values are compared to those obtained in measurements well below and well above the p Ka , where pure phenol or phenolate, respectively, are the dominant species, and where the Gibbs free energy of adsorption determined from surface tension and LJ-PES data are in excellent agreement. At the bulk p Ka the surface-sensitive LJ-PES measurements show a deviation of the expected phenol/phenolate ratio in favor of phenol, i.e. , an apparent upward shift of the at the surface. In addition, the Gibbs free energies of adsorption determined by LJ-PES at the bulk p Ka for phenol and phenolate deviate from those observed for the pure solutions. We discuss these observations in view of the different surface propensity of phenol and phenolate as well as potential cooperative interactions between them in the near-surface region.- Published
- 2024
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26. Multi-task Bayesian model combining FDG-PET/CT imaging and clinical data for interpretable high-grade prostate cancer prognosis.
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Larose M, Archambault L, Touma N, Brodeur R, Desroches F, Raymond N, Bédard-Tremblay D, LeBlanc D, Rasekh F, Hovington H, Neveu B, Vallières M, and Pouliot F
- Subjects
- Humans, Male, Prognosis, Neoplasm Grading, Aged, Middle Aged, Bayes Theorem, Prostatic Neoplasms diagnostic imaging, Prostatic Neoplasms pathology, Positron Emission Tomography Computed Tomography methods, Fluorodeoxyglucose F18
- Abstract
We propose a fully automatic multi-task Bayesian model, named Bayesian Sequential Network (BSN), for predicting high-grade (Gleason ≥ 8) prostate cancer (PCa) prognosis using pre-prostatectomy FDG-PET/CT images and clinical data. BSN performs one classification task and five survival tasks: predicting lymph node invasion (LNI), biochemical recurrence-free survival (BCR-FS), metastasis-free survival, definitive androgen deprivation therapy-free survival, castration-resistant PCa-free survival, and PCa-specific survival (PCSS). Experiments are conducted using a dataset of 295 patients. BSN outperforms widely used nomograms on all tasks except PCSS, leveraging multi-task learning and imaging data. BSN also provides automated prostate segmentation, uncertainty quantification, personalized feature-based explanations, and introduces dynamic predictions, a novel approach that relies on short-term outcomes to refine long-term prognosis. Overall, BSN shows great promise in its ability to exploit imaging and clinicopathological data to predict poor outcome patients that need treatment intensification with loco-regional or systemic adjuvant therapy for high-risk PCa., (© 2024. The Author(s).)
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- 2024
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27. Probing Single-Molecule Dynamics in Self-Assembling Viral Nucleocapsids.
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Bugea T, Suss R, Gargowitsch L, Truong C, Perronet K, and Tresset G
- Abstract
All viruses on Earth rely on host cell machinery for replication, a process that involves a complex self-assembly mechanism. Our aim here is to scrutinize in real time the growth of icosahedral viral nucleocapsids with single-molecule precision. Using total internal reflection fluorescence microscopy, we probed the binding and unbinding dynamics of fluorescently labeled capsid subunits on hundreds of immobilized viral RNA molecules simultaneously at each time point. A step-detection algorithm combined with statistical analysis allowed us to estimate microscopic quantities such as the equilibrium binding rate and mean residence time, which are otherwise inaccessible through traditional ensemble-averaging techniques. Additionally, we could estimate a set of rate constants modeling the growth kinetics from nonequilibrium measurements, and we observed an acceleration in growth caused by the electrostatic screening effect of monovalent salts. Single-molecule fluorescence imaging will be crucial for elucidating virus self-assembly at the molecular level, particularly in crowded, cell-like environments.
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- 2024
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28. Role of Oxide-Derived Cu on the Initial Elementary Reaction Intermediate During Catalytic CO 2 Reduction.
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Jiang Z, Clavaguéra C, Denisov SA, Ma J, and Mostafavi M
- Abstract
The catalytic role of oxide-derived Cu (OD-Cu) in promoting CO
2 reduction (CO2 R) to C2+ products has been appreciated for decades. However, the dynamic evolution of the surface oxidation states, together with their real correlation to the binding of reaction intermediates, remains unclear due to technical challenges. Here, we show the time-resolved spectroscopic signatures of key OD-Cu-CO2 •- intermediates during catalytic CO2 reduction through one electron transfer from nanoseconds to seconds time scale. We generated the initial intermediate CO2 •- radicals in the bulk solution and monitored the interfacial reaction kinetics with well-defined OD-Cu (Cu(0), Cu(I), and Cu(II)) nanoparticles. Combined with molecular simulations, transient absorption profiles analysis reveals that Cu(I) induced a faster CO2 •- radical coupling reaction than Cu(0), whereas Cu(II) is only reduced to Cu(I) by the CO2 •- radical. Furthermore, the newly developed multistep cumulative pulse methodology uncovered the transition in chemical states of mixed OD-Cu during radical coupling reactions. This pulse radiolysis study provides compelling evidence for the beneficial role of subsurface oxides in early time catalytic CO2 transformation.- Published
- 2024
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29. Cumulant Green's function methods for molecules.
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Loos PF, Marie A, and Ammar A
- Abstract
The cumulant expansion of the Green's function is a computationally efficient beyond-GW approach renowned for its significant enhancement of satellite features in materials. In contrast to the ubiquitous GW approximation of many-body perturbation theory, ab initio cumulant expansions performed on top of GW (GW + C) have demonstrated the capability to handle multi-particle processes by incorporating higher-order correlation effects or vertex corrections, yielding better agreements between experiment and theory for satellite structures. While widely employed in condensed matter physics, very few applications of GW + C have been published on molecular systems. Here, we assess the performance of this scheme on a series of 10-electron molecular systems (Ne, HF, H
2 O, NH3 , and CH4 ) where full configuration interaction estimates of the outer-valence quasiparticle and satellite energies are available.- Published
- 2024
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30. Role of molecular damage in crack initiation mechanisms of tough elastomers.
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Ju J, Sanoja GE, Cipelletti L, Ciccotti M, Zhu B, Narita T, Yuen Hui C, and Creton C
- Abstract
Tough soft materials such as multiple network elastomers (MNE) or filled elastomers are typically stretchable and include significant energy dissipation mechanisms that prevent or delay crack growth. Yet most studies and fracture models focus on steady-state propagation and damage is assumed to be decoupled from the local stress and strain fields near the crack tip. We report an in situ spatial-temporally resolved 3D measurement of molecular damage in mechanophore-labeled MNE just before a crack propagates. This technique, complemented by digital image correlation, allows us to compare the spatial distribution of both damage and deformation in single network (SN) elastomers and in MNE. Compared to SN, MNE have a wide-spread damage in front of the crack and, surprisingly, delocalize strain concentration. A continuum model, where damage distribution is fully coupled to the crack tip fields, is proposed to explain these results. Additional measurements of time-dependent molecular damage during fixed grips relaxation in the presence of a crack reveal that the less localized damage distribution delays fracture initiation. The observations and exploratory modeling reveal the dynamic fracture mechanism of MNE, providing guidance for rational design of high-performance tough elastomers., Competing Interests: Competing interests statement:The authors declare no competing interest.
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- 2024
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31. Transforming Nanocrystals into Superhard Boron Carbide Nanostructures.
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Igoa Saldaña F, Gaudisson T, Le Floch S, Baptiste B, Delbes L, Malarewicz V, Beyssac O, Béneut K, Coelho Diogo C, Gervais C, Rousse G, Rasim K, Grin Y, Maître A, Le Godec Y, and Portehault D
- Abstract
Boron carbide (B
4+δ C) possesses a large potential as a structural material owing to its lightness, refractory character, and outstanding mechanical properties. However, its large-scale industrialization is set back by its tendency to amorphize when subjected to an external stress. In the present work, we design a path toward nanostructured boron carbide with greatly enhanced hardness and resistance to amorphization. The reaction pathway consists of triggering an isomorphic transformation of covalent nanocrystals of Na1- x B5- x C1+ x ( x = 0.18) produced in molten salts. The resulting 10 nm B4.1 C nanocrystals exhibit a 4-fold decrease of size compared to previous works. Solid-state11 B and13 C NMR coupled to density functional theory (DFT) reveal that the boron carbide nanocrystals are made of a complex mixture of atomic configurations, which are located at the covalent structural chains between B11 C icosahedral building units. These nanocrystals are combined with a spark plasma-sintering-derived method operated at high pressure. This yields full densification while maintaining the particle size. The nanoscaled grains and high density of grain boundaries provide the resulting nanostructured bodies with significantly enhanced hardness and resistance to amorphization, thus delivering a superhard material.- Published
- 2024
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32. Broadband Rotational Spectroscopy in Uniform Supersonic Flows: Chirped Pulse/Uniform Flow for Reaction Dynamics and Low Temperature Kinetics.
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Dias N, Suas-David N, Thawoos S, and Suits AG
- Abstract
ConspectusThe study of gas-phase chemical reactions at very low temperatures first became possible with the development and implementation of the CRESU (French acronym for Reaction Kinetics in Uniform Supersonic Flows) technique. CRESU relies on a uniform supersonic flow produced by expansion of a gas through a Laval (convergent-divergent) nozzle to produce a wall-less reactor at temperatures from 10 to 200 K and densities of 10
16 -1018 cm-3 for the study of low temperature kinetics, with particular application to astrochemistry. In recent years, we have combined uniform flows with revolutionary advances in broadband rotational spectroscopy to yield an instrument that affords near-universal detection for novel applications in photodissociation, reaction dynamics, and kinetics. This combination of uniform supersonic flows with chirped-pulse Fourier-transform microwave spectroscopy (Chirped-Pulse/Uniform Flow, CPUF) permits detection of any species with a modest dipole moment, thermalized to the uniform temperature of the gas flow, with isomer, conformer, and vibrational state specificity. In addition, the use of broadband, high-resolution, and time-dependent (microsecond time scale) micro- and mm-wave spectroscopy makes it an ideal tool for characterizing both transient and stable molecules, as well as studying their spectroscopy and dynamics.In this Account, we review recent advances made using the CPUF technique, including studies of photodissociation, radical-radical reaction dynamics, and low temperature kinetics. These studies highlight both the strength of universal and multiplexed detection and the challenges of coupling it to a high-density collisional environment. Product branching and product evolution as a function of time have been measured for astrochemically relevant systems, relying on the detailed characterization of these flow conditions via experiments and fluid dynamics simulations. In the photodissociation of isoxazole, an unusual heterocyclic molecule with a very low-energy conical intersection, we have identified 7 products in 5 reaction channels and determined the product branching, pointing to both direct and indirect pathways. We have also approached the same system from separated NO and C3 H3 reactants to explore a broader range of the potential energy surface, demonstrating the power of multichannel branching measurements for complex radical-radical reactions. We determined the product branching in the C3 H2 isomers in the photodissociation of the propargyl radical and identified the importance of a hydrogen atom catalyzed isomerization to the lowest energy cyclic form. This then motivated a study of direct D-H exchange reaction in radicals, in which we demonstrate that it is an important and overlooked pathway for deuterium fractionation in astrochemical environments. Recently, we have shown the measurement of low temperature kinetics inside an extended Laval nozzle, after which a shock-free secondary expansion to low temperature and density affords an ideal environment for detection by rotational spectroscopy. These results highlight the power and potential of the CPUF approach, and future prospects will also be discussed in light of these developments.- Published
- 2024
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33. Shearmetry of Fluids with Tunable Rheology by Polarized Luminescence of Rare Earth-Doped Nanorods.
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Wang Z, Zou Q, Magermans L, Amselem G, Dessalles CA, Louis B, Filoche M, Gacoin T, and Kim J
- Subjects
- Luminescence, Rheology, Nanotubes chemistry, Metals, Rare Earth chemistry
- Abstract
Shear stress plays a critical role in regulating physiological processes within microcirculatory systems. While particle imaging velocimetry is a standard technique for quantifying shear flow, uncertainty near boundaries and low resolution remain severe restrictions. Additionally, shear stress determination is particularly challenging in biofluids due to their significant non-Newtonian behaviors. The present study develops a shearmetry technique in physiological settings using a biomimetic fluid containing rare earth-doped luminescent nanorods acting in two roles. First, they are used as colloidal additives adjusting rheological properties in physiological media. Their anisotropic morphology and interparticle interaction synergistically induce a non-Newtonian shear-thinning effect emulating real biofluids. Second, they can probe shear stress due to the shear-induced alignment. The polarized luminescence of the nanorods allows for quantifying their orientational order parameter and thus correlated shear stress. Using scanning confocal microscopy, we demonstrate the tomographic mapping of the shear stress distribution in microfluidics. High shear stress is evident near the constriction and the cellular periphery, in which non-Newtonian effects can have a significant impact. This emerging shearmetry technique is promising for implementation in physiological and rheological environments of biofluids.
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- 2024
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34. Exploring the potent corrosion inhibition properties of phenolic Schiff bases on mild steel in acidic environments, part A: coupling experimental and theoretical investigations.
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Lahhit A, Azghay I, Elyoussfi A, Ghalit M, Ouzidan Y, Massaoudi ME, Mourabit F, Akichouh EH, Ahari M', Amhamdi H, and Salhi A
- Abstract
In this study, we conduct a comparative investigation into the corrosion inhibition properties of two Schiff base compounds, namely 4,4'-((1E,1'E)-(ethane-1,2 diylbis(azaneylylidene))bis(methaneylylidene))diphenol (PSB5) and (1E,1'E)-N,N'-(ethane-1,2 diyl)bis(1-(4-nitrophenyl)methanimine) (PSB6), on mild steel in an acidic environment. The inhibitory efficiency and adsorption behavior of the inhibitors were assessed through electrochemical and gravimetric analyses. The inhibitors' deposition was further verified by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The findings of electrochemical tests demonstrate that these chemical compounds are potent inhibitors, with 96.5% inhibition provided by PSB5 at 10
-3 M. Therefore, PSB5 and PSB6 inhibitors are likely of mixed-form, as evidenced by changes in their Ecorr values of 59.8 mV and 33.0 mV, respectively when compared to the blank solution. Furthermore, the adsorption of these inhibitors onto the MS surface, as determined by the Langmuir adsorption isotherm, yielded free energy values of - 38.40 kJ mol-1 for PSB5 and - 35.20 kJ mol-1 for PSB6. These findings highlight a robust and spontaneous adsorption process for both inhibitors. Surface analysis using SEM-EDS revealed the preservation of the mild steel surface morphology and the adsorption of inhibitors. Theoretical investigations utilizing density functional theory (DFT) and molecular dynamics (MD) simulations supported and complemented the experimental findings. This research enhances the understanding of the corrosion protection potential of Schiff base compounds and their potential applications in various industries., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)- Published
- 2024
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35. Active Photonic Glass for Hydrogen Generation.
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Wang C, Johar M, Ullah W, Paineau E, Li J, and Ghazzal MN
- Abstract
Chirality is vital in many living species since it is responsible for structural iridescent coloration and plays a key role in light harvesting during natural photosynthesis. Developing photoactive materials with such chiral structures is a challenging but promising strategy for energy applications. Here, we describe a straightforward method to establish an active photonic glass obtained through the co-condensation of tetramethyl orthosilicate (TMOS) and titanium diisopropoxide bis(acetylacetonate) (TAA) dissolved in a liquid crystal formed from cellulose nanocrystalline (CNC). The inorganic glass maintains a long range of chiral nematic ordering, displaying iridescent colors characterized by a Bragg peak reflection. The reflected wavelengths are tuned all over the UV-visible range, demonstrating that the replica of the chiral nematic structure generates photonic properties. Incorporation of gold nanoparticles (Au NPs) into the films is further performed by impregnation/chemical reduction. We show that the charge carrier density and photocatalytic H2 generation were amplified when the photonic band gap edges matched the absorbance of the TiO2 and localized surface plasmon resonance (LSPR) of AuNPs. This photocatalytic glass with chiral nematic ordering and a tunable photonic bandgap paves the way for the development of metamaterials with new applications, such as asymmetric photocatalysis., (© 2024 Wiley‐VCH GmbH.)
- Published
- 2024
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36. Strain-affected ferroelastic domain walls in RbMnFe charge-transfer materials undergoing collective Jahn-Teller distortion.
- Author
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Hervé M, Akagi S, Guérin L, Gee LB, Ribson RD, Chollet M, Cammarata M, Nagashima S, Ohkoshi SI, Tokoro H, and Collet E
- Abstract
Many rubidium manganese hexacyanoferrate materials, with the general formula Rb
x Mn[Fe(CN)6 ]( x +2)/3 · z H2 O, exhibit diverse charge-transfer-based functionalities due to the bistability between a high temperature MnII ( S = 5/2)FeIII ( S = 1/2) cubic phase and a low-temperature MnIII ( S = 2)FeII ( S = 0) tetragonal phase. The collective Jahn-Teller distortion on the Mn sites is responsible for the cubic-to-tetragonal ferroelastic phase transition, which is associated with the appearance of ferroelastic domains. In this study, we use X-ray diffraction to reveal the coexistence of 3 types of ferroelastic tetragonal domains and estimate the spatial extension of the strain around the domain walls, which represents about 30% of the volume of the crystal., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2024
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37. Reduction of lower limb spasticity after the suppression of intravesical noxious stimulus documented by gait analysis.
- Author
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Ribault S, Oberle C, Ardaillon H, Arsenault L, Gailleton J, Delporte L, and Rode G
- Abstract
Context: Spasticity is characterized by muscle hypertonia due to a velocity-dependent increase in tonic stretch reflexes, mostly related to hyperactive spinal reflexes. After spinal cord injury, the impact of noxious stimuli on autonomic dysreflexia is well documented. It is admitted in clinical practice that sublesional noxious stimuli can also increase spasticity. However, this has never been reported in the literature. In this single case study, we describe the impact of a noxious stimulus (bladder stone) on the spasticity of lower limbs in a male with spinal cord injury, using quantitative gait analysis before and after stone removal., Findings: : Clinical evaluation was performed on the subject before and after bladder lithiasis removal, by two physiotherapists using ASIA score and the Modified Ashworth scale. Quantitative gait analyses were compared before and 3 months after lithiasis resection.Regarding gait kinematics, there was a reduction of the right knee recurvatum, and of the successive increases of flexion (double bump) of flexion in the swing phase. In the stance phase, the right ankle maximum dorsiflexion increased. In the swing phase, the double bump of ankle dorsiflexion disappeared. Surface electromyography showed a reduction of the triceps surae hypertonia, especially in the right gastrocnemius muscle at the swing., Conclusion: We propose that lithiasis created a noxious stimulus regarding the S2, S3 and S4 metamers with a diffusion of the spinal reflex to the metamers S1, S2, S3 and S4. This highlights a potential causal link between an intravesical noxious stimulus and an increase in the subject's spasticity, through a disinhibited spinal nociceptive reflex.
- Published
- 2024
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38. Submicrometre spatiotemporal characterization of the Toxoplasma adhesion strategy for gliding motility.
- Author
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Vigetti L, Touquet B, Debarre D, Rose T, Bureau L, Abdallah D, Dubacheva GV, and Tardieux I
- Abstract
Toxoplasma gondii is a protozoan apicomplexan parasite that uses an adhesion-dependent mode of motility termed gliding to access host cells and disseminate into tissues. Previous studies on Apicomplexa motile morphotypes, including the T. gondii tachyzoite, have identified a cortical actin-myosin motor system that drives the rearward translocation of transmembrane adhesins, thus powering forward movement. However, this model is currently questioned. Here, combining micropatterning and tunable surface chemistry (to edit parasite surface ligands) with flow force and live or super-resolution imaging, we show that tachyzoites build only one apical anchoring contact with the substrate, over which it slides. Furthermore, we show that glycosaminoglycan-parasite interactions are sufficient to promote such force-productive contact and find that the apicobasal flow is set up independent of adhesin release and surface interactions. These findings should enable further characterization of the molecular functions at the T. gondii-substrate mechanosensitive interface and their comparison across apicomplexans., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)
- Published
- 2024
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39. Congenital myasthenic syndromes in adults: clinical features, diagnosis and long-term prognosis.
- Author
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Theuriet J, Masingue M, Behin A, Ferreiro A, Bassez G, Jaubert P, Tarabay O, Fer F, Pegat A, Bouhour F, Svahn J, Petiot P, Jomir L, Chauplannaz G, Cornut-Chauvinc C, Manel V, Salort-Campana E, Attarian S, Fortanier E, Verschueren A, Kouton L, Camdessanché JP, Tard C, Magot A, Péréon Y, Noury JB, Minot-Myhie MC, Perie M, Taithe F, Farhat Y, Millet AL, Cintas P, Solé G, Spinazzi M, Esselin F, Renard D, Sacconi S, Ezaru A, Malfatti E, Mallaret M, Magy L, Diab E, Merle P, Michaud M, Fournier M, Pakleza AN, Chanson JB, Lefeuvre C, Laforet P, Richard P, Sternberg D, Villar-Quiles RN, Stojkovic T, and Eymard B
- Subjects
- Humans, Female, Male, Adult, Prognosis, Middle Aged, Retrospective Studies, Young Adult, France epidemiology, Adolescent, Muscle Proteins genetics, Aged, Follow-Up Studies, Myasthenic Syndromes, Congenital genetics, Myasthenic Syndromes, Congenital diagnosis, Myasthenic Syndromes, Congenital physiopathology
- Abstract
Congenital myasthenic syndromes (CMS) are clinically and genetically heterogeneous diseases caused by mutations affecting neuromuscular transmission. Even if the first symptoms mainly occur during childhood, adult neurologists must confront this challenging diagnosis and manage these patients throughout their adulthood. However, long-term follow-up data from large cohorts of CMS patients are lacking, and the long-term prognosis of these patients is largely unknown. We report the clinical features, diagnostic difficulties, and long-term prognosis of a French nationwide cohort of 235 adult patients with genetically confirmed CMS followed in 23 specialized neuromuscular centres. Data were retrospectively analysed. Of the 235 patients, 123 were female (52.3%). The diagnosis was made in adulthood in 139 patients, 110 of whom presented their first symptoms before the age of 18. Mean follow-up time between first symptoms and last visit was 34 years [standard deviation (SD) = 15.1]. Pathogenic variants were found in 19 disease-related genes. CHRNE-low expressor variants were the most common (23.8%), followed by variants in DOK7 (18.7%) and RAPSN (14%). Genotypes were clustered into four groups according to the initial presentation: ocular group (CHRNE-LE, CHRND, FCCMS), distal group (SCCMS), limb-girdle group (RAPSN, COLQ, DOK7, GMPPB, GFPT1), and a variable-phenotype group (MUSK, AGRN). The phenotypical features of CMS did not change throughout life. Only four genotypes had a proportion of patients requiring intensive care unit admission that exceeded 20%: RAPSN (54.8%), MUSK (50%), DOK7 (38.6%) and AGRN (25.0%). In RAPSN and MUSK patients most ICU admissions occurred before age 18 years and in DOK7 and AGRN patients at or after 18 years of age. Different patterns of disease course (stability, improvement and progressive worsening) may succeed one another in the same patient throughout life, particularly in AGRN, DOK7 and COLQ. At the last visit, 55% of SCCMS and 36.3% of DOK7 patients required ventilation; 36.3% of DOK7 patients, 25% of GMPPB patients and 20% of GFPT1 patients were wheelchair-bound; most of the patients who were both wheelchair-bound and ventilated were DOK7 patients. Six patients died in this cohort. The positive impact of therapy was striking, even in severely affected patients. In conclusion, even if motor and/or respiratory deterioration could occur in patients with initially moderate disease, particularly in DOK7, SCCMS and GFPT1 patients, the long-term prognosis for most CMS patients was favourable, with neither ventilation nor wheelchair needed at last visit. CHRNE-LE patients did not worsen during adulthood and RAPSN patients, often severely affected in early childhood, subsequently improved., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain.)
- Published
- 2024
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40. Effect of a back-support exoskeleton on internal forces and lumbar spine stability during low load lifting task.
- Author
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Eskandari AH, Ghezelbash F, Shirazi-Adl A, Arjmand N, and Larivière C
- Abstract
This study assessed the effect of a small-torque generating passive back-support exoskeleton during a low demanding occupational task, namely a repetitive lifting/lowering of an empty crate between the knee and shoulder heights. A comprehensive set of outcomes was considered, ranging from the measured trunk muscle activation and trunk movement to the estimated muscle group forces/coordination, spine loading and spine stability, using a dynamic subject-specific EMG-assisted musculoskeletal model. The exoskeleton decreased back muscle activation and corresponding muscle forces in the lowering phase and reduced spinal loading at larger trunk flexion angles (decreased peak compression and shear forces by ∼ 15%). However, the effect sizes were small (η
G 2 < .06), questioning the usefulness of this type of exoskeleton, even for light tasks. On the other hand, the unique results of the present study showed that coordination between the main muscle groups as well as spinal stability remained unchanged with low effect sizes, suggesting that the use of this exoskeleton is safe., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)- Published
- 2024
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41. Seeing the piles of the velvet bending under our finger sliding over a tactile stimulator improves the feeling of the fabric.
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Mouchnino L, Camillieri B, Faucheu J, Juganaru M, Moinon A, Blouin J, and Bueno MA
- Subjects
- Humans, Male, Female, Adult, Touch Perception physiology, Touch physiology, Textiles, Fingers physiology
- Abstract
Using friction modulation to simulate fabrics with a tactile stimulator (i.e. virtual surface) is not sufficient to render fabric touch and even more so for hairy fabrics. We hypothesized that seeing the pile of the velvet darken or lighten depending on changes in the finger movement direction on the virtual surface should improve the velvet fabric rendering. Participants actively rubbed a tactile device or a velvet fabric looking at a screen that showed a synthesized image of a velvet that either remained static (V-static) or darkening/lightening with the direction of touch (V-moving). We showed that in V-moving condition, the touched surface was always perceived rougher, which is a descriptor of a real velvet (Experiment 1). Using electroencephalography and sources localization analyses, we found increased activity in the occipital and inferior parietal lobes (Experiment 2) when seeing dark and shining traces during back-and-forth finger movements over the virtual surface. This suggests that these two posterior cortical regions work together to evaluate visuo-tactile congruence between the seen and the felt (tactile). The visuo-tactile binding, evidenced by neural synchronization (specifically, theta band (5-7 Hz) oscillation) in the left inferior posterior parietal lobule, is consistent with enhanced integration of information and probably contributed to the emergence of a more realistic velvet representation.
- Published
- 2024
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42. Ultrastructural Perspectives on the Biology and Taphonomy of Tonian Microfossils From the Draken Formation, Spitsbergen.
- Author
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Fadel A, Lepot K, Bernard S, Addad A, Riboulleau A, and Knoll AH
- Subjects
- Geologic Sediments microbiology, X-Ray Absorption Spectroscopy, Cyanobacteria ultrastructure, Spectrum Analysis, Raman, Carbonates chemistry, Fossils, Microscopy, Electron, Transmission
- Abstract
Silicified peritidal carbonates of the Tonian Draken Formation, Spitsbergen, contain highly diverse and well-preserved microfossil assemblages dominated by filamentous microbial mats, but also including diverse benthic and/or allochthonous (possibly planktonic) microorganisms. Here, we characterize eight morphospecies in focused ion beam (FIB) ultrathin sections using transmission electron microscopy (TEM) and X-ray absorption near-edge structure (XANES) spectromicroscopy. Raman and XANES spectroscopies show the highly aromatic molecular structure of preserved organic matter. Despite this apparently poor molecular preservation, nano-quartz crystallization allowed for the preservation of various ultrastructures distinguished in TEM. In some filamentous microfossils (Siphonophycus) as well as in all cyanobacterial coccoids, extracellular polysaccharide sheaths appear as bands of dispersed organic nanoparticles. Synodophycus microfossils, made up of pluricellular colonies of coccoids, contain organic walls similar to the F-layers of pleurocapsalean cyanobacteria. In some fossils, internal content occurs as particulate organic matter, forming dense networks throughout ghosts of the intracellular space (e.g., in Salome svalbardensis filaments), or scarce granules (in some Chroococcales). In some chroococcalean microfossils (Gloeodiniopsis mikros, and also possibly Polybessurus), we find layered internal contents that are more continuous than nanoparticulate bands defining the sheaths, and with a shape that can be contracted, folded, or invaginated. We interpret these internal layers as the remains of cell envelope substructures and/or photosynthetic membranes thickened by additional cellular material. Some Myxococccoides show a thick (up to ~ 0.9 μm) wall ultrastructure displaying organic pillars that is best reconciled with a eukaryotic affinity. Finally, a large spheroid with ruptured wall, of uncertain affinity, displays a bi-layered envelope. Altogether, our nanoscale investigations provide unprecedented insights into the taphonomy and taxonomy of this well-preserved assemblage, which can help to assess the nature of organic microstructures in older rocks., (© 2024 The Author(s). Geobiology published by John Wiley & Sons Ltd.)
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- 2024
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43. Electrical resistivity tomography of simulated graves with buried human and pig remains.
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Cristino K, Doro KO, Armstrong A, Forbes S, Ribéreau-Gayon A, and Bank CG
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- Animals, Humans, Swine, Body Remains, Postmortem Changes, Models, Animal, Soil, Forensic Sciences methods, Burial, Electric Impedance, Tomography
- Abstract
Rigorous field assessment in different soil types and climates comparing simulated graves with pig remains and human remains are needed to assess the capabilities and limitations of electrical resistivity tomography (ERT) as a tool to search for unmarked graves. Our study assesses the ERT signals from graves with pig and human remains in a cold, humid continental climate with sandy soils. Two sets of three experimental graves were established: the first set consisted of two graves containing human remains and an empty grave serving as a control, while the second set consisted of two graves with pig remains and a second empty grave. ERT measurements were conducted prior to establishing the graves and were repeated 10 times over seventeen months, except for winter months when measurements were impossible. Each time we acquired eight 18 m long ERT transects using a dipole-dipole electrode array with a unit electrode spacing of 0.5 m and the transects spaced 1 m apart. The measured electrical resistivity decreased for all graves by 14-22 % for measurements conducted up to two months after burial. No further decrease was observed in the control, while resistivity in the graves with human and pig remains continued to decrease by 45-52 % up to the end of our study, seventeen months after burial. The resistivity anomaly in the pig graves shows a contrasting anomaly that is broader than that of the human remains. Our study thus validates the sensitivity of ERT to graves in cold, humid climates with sandy soil., Competing Interests: Declaration of Competing Interest None., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)
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- 2024
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44. [Events and errors in radiation oncology: Conciliating perspectives to support care].
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Haaser T, Constantinides Y, Osman D, Lahmi L, Durdux C, Bourbonne V, Cheval V, de Crevoisier R, Dejean C, Ducteil A, Escande A, Gesbert C, Ghannam Y, Lemanski C, Thureau S, Lagrange JL, and Huguet F
- Subjects
- Humans, Neoplasms radiotherapy, Neoplasms psychology, Radiation Oncology, Medical Errors prevention & control
- Abstract
The term "event" covers a wide range of concrete situations in radiation oncology, from particularly intense radiation-related side effects to the possibility of technical or human error. Although quality procedures are an integral part of radiotherapy oncology department operations ensuring the analysis and prevention of such events, their occurrence during radiation treatment still has a significant impact on patients and their experience of the treatment process, as well as on health professionals. These practical, emotional and symbolic impacts are all the greater when the event occurs in the aftermath of an error. The ethical approach therefore comprises three essential stages: recognizing the event as such, informing those involved of the event and, finally, creating conditions for the continuation of care. Each of these stages is marked by specific issues and questions, requiring a complex ethical approach that constantly involves reconciling the possible divergent perceptions of patients and health professionals. The occurrence of an event can also lead to a genuine crisis of confidence with multiple dimensions, which health professionals will also have to face and to support. Finally, the occurrence of an event calls into question not only our responsibility towards patients, but also our ideal of control. We need to criticize our culture of performance, rethink our approach to events and errors, and see them also as opportunities for positive change., (Copyright © 2024 Société française de radiothérapie oncologique (SFRO). Published by Elsevier Masson SAS. All rights reserved.)
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- 2024
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45. Biallelic variants in ERLIN1: a series of 13 individuals with spastic paraparesis.
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Cogan G, Zaki MS, Issa M, Keren B, Guillaud-Bataille M, Renaldo F, Isapof A, Lallemant P, Stevanin G, Guillot-Noel L, Courtin T, Buratti J, Freihuber C, Gleeson JG, Howarth R, Durr A, de Sainte Agathe JM, and Mignot C
- Subjects
- Humans, Female, Male, Child, Adolescent, Adult, Membrane Proteins genetics, Alleles, Phenotype, Mutation, Child, Preschool, Young Adult, Intellectual Disability genetics, Paraparesis, Spastic genetics, Pedigree
- Abstract
Biallelic variants in the ERLIN1 gene were recently reported as the cause of two motor neuron degeneration diseases, SPG62 and a recessive form of amyotrophic lateral sclerosis. However, only 12 individuals from five pedigrees have been identified so far. Thus, the description of the disease remains limited. Following the discovery of a homozygous pathogenic variant in a girl with SPG62, presenting with intellectual disability, and epilepsy, we gathered the largest series of SPG62 cases reported so far (13 individuals) to better understand the phenotype associated with ERLIN1. We collected molecular and clinical data for 13 individuals from six families with ERLIN1 biallelic variants. We performed RNA-seq analyses to characterize intronic variants and used Alphafold and a transcripts database to characterize the molecular consequences of the variants. We identified three new variants suspected to alter the bell-shaped ring formed by the ERLIN1/ERLIN2 complex. Affected individuals had childhood-onset paraparesis with slow progression. Six individuals presented with gait ataxia and three had superficial sensory loss. Aside from our proband, none had intellectual disability or epilepsy. Biallelic pathogenic ERLIN1 variants induce a rare, predominantly pure, spastic paraparesis, with possible cerebellar and peripheral nerve involvement., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
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- 2024
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46. Validation evidence with experimental and clinical data to establish credibility of TAVI patient-specific simulations.
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Grossi B, Barati S, Ramella A, Migliavacca F, Rodriguez Matas JF, Dubini G, Chakfé N, Heim F, Cozzi O, Condorelli G, Stefanini GG, and Luraghi G
- Subjects
- Humans, Male, Finite Element Analysis, Female, Heart Valve Prosthesis, Tomography, X-Ray Computed, Aged, Aortic Valve Stenosis surgery, Aortic Valve Stenosis diagnostic imaging, Aortic Valve Stenosis physiopathology, Aged, 80 and over, Transcatheter Aortic Valve Replacement methods, Models, Cardiovascular, Aortic Valve surgery, Aortic Valve diagnostic imaging
- Abstract
Purpose: The objective of this study is to validate a novel workflow for implementing patient-specific finite element (FE) simulations to virtually replicate the Transcatheter Aortic Valve Implantation (TAVI) procedure., Methods: Seven patients undergoing TAVI were enrolled. Patient-specific anatomical models were reconstructed from pre-operative computed tomography (CT) scans and subsequentially discretized, considering the native aortic leaflets and calcifications. Moreover, high-fidelity models of CoreValve Evolut R and Acurate Neo2 valves were built. To determine the most suitable material properties for the two stents, an accurate calibration process was undertaken. This involved conducting crimping simulations and fine-tuning Nitinol parameters to fit experimental force-diameter curves. Subsequently, FE simulations of TAVI procedures were conducted. To validate the reliability of the implemented implantation simulations, qualitative and quantitative comparisons with post-operative clinical data, such as angiographies and CT scans, were performed., Results: For both devices, the simulation curves closely matched the experimental data, indicating successful validation of the valves mechanical behaviour. An accurate qualitative superimposition with both angiographies and CTs was evident, proving the reliability of the simulated implantation. Furthermore, a mean percentage difference of 1,79 ± 0,93 % and 3,67 ± 2,73 % between the simulated and segmented final configurations of the stents was calculated in terms of orifice area and eccentricity, respectively., Conclusion: This study shows the successful validation of TAVI simulations in patient-specific anatomies, offering a valuable tool to optimize patients care through personalized pre-operative planning. A systematic approach for the validation is presented, laying the groundwork for enhanced predictive modeling in clinical practice., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)
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- 2024
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47. Materials Acceleration Platforms (MAPs): Accelerating Materials Research and Development to Meet Urgent Societal Challenges.
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Stier SP, Kreisbeck C, Ihssen H, Popp MA, Hauch J, Malek K, Reynaud M, Goumans TPM, Carlsson J, Todorov I, Gold L, Räder A, Wenzel W, Bandesha ST, Jacques P, Garcia-Moreno F, Arcelus O, Friederich P, Clark S, Maglione M, Laukkanen A, Castelli IE, Carrasco J, Cabanas MC, Stein HS, Ozcan O, Elbert D, Reuter K, Scheurer C, Demura M, Han SS, Vegge T, Nakamae S, Fabrizio M, and Kozdras M
- Abstract
Climate Change and Materials Criticality challenges are driving urgent responses from global governments. These global responses drive policy to achieve sustainable, resilient, clean solutions with Advanced Materials (AdMats) for industrial supply chains and economic prosperity. The research landscape comprising industry, academe, and government identified a critical path to accelerate the Green Transition far beyond slow conventional research through Digital Technologies that harness Artificial Intelligence, Smart Automation and High Performance Computing through Materials Acceleration Platforms, MAPs. In this perspective, following the short paper, a broad overview about the challenges addressed, existing projects and building blocks of MAPs will be provided while concluding with a review of the remaining gaps and measures to overcome them., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)
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- 2024
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48. Factors Related to Firefighters' Food Behaviors at the Fire Station: A Quantitative Study.
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Sire T, Carbonneau N, Houle J, Trudeau F, and Gendron P
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- Humans, Male, Adult, Cross-Sectional Studies, Middle Aged, Female, Surveys and Questionnaires, Motivation, Health Knowledge, Attitudes, Practice, Body Mass Index, Fast Foods, Diet, Healthy, Firefighters psychology, Firefighters statistics & numerical data, Feeding Behavior psychology
- Abstract
Objective: Using a cross-sectional correlational study, the purpose was to quantitatively investigate factors associated to firefighters' food behaviors while on duty at the fire station., Methods: Two hundred and fifty-two (252) firefighters (males, 96%; age, 39 ± 11 years) completed an online questionnaire assessing diet and exploring factors that could be associated to firefighters' food behaviors at the fire station., Results: First regression analysis showed that level of education, years of experience, self-perceived nutrition knowledge, autonomous motivation, and accessibility to unhealthy foods were the best predictors of healthy food score. Second regression analysis revealed that body mass index, autonomous motivation, and meals interrupted by emergency calls were the best predictors of fast-food score., Conclusions: This study highlights the various factors associated with firefighters' food behaviors at the fire station., Competing Interests: Conflict of interest: None declared., (Copyright © 2024 American College of Occupational and Environmental Medicine.)
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- 2024
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49. Longitudinal changes in Achilles tendon and triceps surae muscle architecture during a 156-km mountain ultramarathon.
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Drigny J, Remilly M, Hingrand C, and Mauvieux B
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- Humans, Male, Adult, Middle Aged, Female, Ultrasonography methods, Running physiology, Longitudinal Studies, Physical Endurance physiology, Achilles Tendon diagnostic imaging, Achilles Tendon physiology, Achilles Tendon anatomy & histology, Muscle, Skeletal physiology, Muscle, Skeletal diagnostic imaging, Muscle, Skeletal anatomy & histology, Marathon Running physiology
- Abstract
This study aimed to assess the longitudinal changes in triceps surae muscle-tendon architecture during a mountain ultramarathon. Experienced trail runners [ n = 55, 78% men, age: 45.2 (13.5) yr] participated in a 156-km trail run (6,000 m climbing) consisting of six 26-km laps. The resting architectural properties of triceps surae muscle-tendon were measured using ultrasound imaging for Achilles tendon cross-sectional area (AT CSA), medial gastrocnemius muscle pennation angle, thickness, length, and fiber length. Measurements were performed the day before the race (baseline), at 52 km (T1), at 104 km (T2), at 156 km (T3), and 12 h after the race (H12). Among finishers ( n = 41), there was a significant biphasic change in AT CSA during the race ( P = 0.001). First, a significant decrease in AT CSA occurred between baseline and T1 ( P = 0.006), with a greater decrease for participants averaging speed >8 km/h ( P = 0.014). Second, there was a significant increase in AT CSA especially between T2 and T3 ( P = 0.006) that was correlated with a decrease in average speed ( P = 0.001) and alteration of spaciotemporal running parameters ( P < 0.05). Changes in muscle-tendon architecture were not significantly different between finishers ( n = 41) and nonfinishers ( n = 14). In 47 participants (85.5%) who completed the follow-up, AT CSA at H12 was greater compared with baseline ( P = 0.010). The main finding is the significant and biphasic modification of the AT CSA during a 156-km mountain ultramarathon with an initial decrease corresponding to mechanical stress followed by a secondary increase suggesting adaptive mechanotransduction persisting after 12 h. NEW & NOTEWORTHY Achilles tendon cross-sectional area (AT CSA) demonstrated significant adaptive modifications during a 156 km mountain ultramarathon in trained athletes. Initially, a decrease in AT CSA, especially at higher running speeds, is consecutive to the biomechanical stress on the plantar flexor muscle-tendon unit (MTU). Subsequently, there is a significant increase in AT CSA persisting up to 12 h after the race, which likely corresponds to an adaptive process to limit the compressive and tensile load on the tendon.
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- 2024
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50. Model based analysis of trace metal dosing strategies to improve methane yield in anaerobic digestion systems.
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George S, Rosaria Mattei M, Frunzo L, Esposito G, van Hullebusch ED, and Fermoso FG
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- Anaerobiosis, Trace Elements metabolism, Computer Simulation, Models, Theoretical, Methane metabolism, Bioreactors, Metals
- Abstract
Favourable effects of trace metals (TMs) on regulating anaerobic digestion (AD) performance are extensively utilised to improve methane yield. This study discusses a model-based approach to find out the best TM dosing strategies. The model has been applied to compare continuous, preloading, pulse dosing and in-situ loading. Simulations were also carried out to comprehend appropriate dosing form, dosing time and quantity of metals to be dosed. Model results show that the best way to dose TMs is repeated pulse dosing at low concentration levels in the optimum range with high frequency. Best dosing strategy for the system in this study was found to be 5 µM pulse loading at 5 days intervals as it gave maximum methane production and low effluent metal loss. Preferable dosing form depends on reactor configuration and this has been verified after model calibration with experimental data. Easily dissociable metal chlorides are ideal for continuous reactors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)
- Published
- 2024
- Full Text
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