HAL Portal ESPCI (Ecole Supérieure de Physique et de Chimie Industrielles)
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Amplitude-Modulated Singular Value Decomposition for Ultrafast Ultrasound Imaging of Gas Vesicles
No full textInternational audienceUltrasound imaging holds significant promise for the observation of molecular and cellular phenomena through the utilization of acoustic contrast agents and acoustic reporter genes. Optimizing imaging methodologies for enhanced detection represents an imperative advancement in this field. Most advanced techniques relying on amplitude modulation schemes such as cross amplitude modulation (xAM) and ultrafast amplitude modulation (uAM) combined with Hadamard encoded multiplane wave transmissions have shown efficacy in capturing the acoustic signals of gas vesicles (GVs). Nonetheless, uAM sequence requires odd- or even-element transmissions leading to imprecise amplitude modulation emitting scheme, and the complex multiplane wave transmission scheme inherently yields overlong pulse durations. xAM sequence is limited in terms of field of view and imaging depth. To overcome these limitations, we introduce an innovative ultrafast imaging sequence called amplitude-modulated singular value decomposition (SVD) processing. Our method demonstrates a contrast imaging sensitivity comparable to the current gold-standard xAM and uAM, while requiring 4.8 times fewer pulse transmissions. With a similar number of transmit pulses, amplitude-modulated SVD outperforms xAM and uAM in terms of an improvement in signal-to-background ratio of +4.78 ± 0.35 dB and +8.29 ± 3.52 dB, respectively. Furthermore, the method exhibits superior robustness across a wide range of acoustic pressures and enables high-contrast imaging in ex vivo and in vivo settings. Furthermore, amplitude-modulated SVD is envisioned to be applicable for the detection of slow moving microbubbles in ultrasound localization microscopy (ULM)
Reactive mixing enables enzymatic depolymerization of recalcitrant or unsortable polyester wastes
No full textInternational audienceEnzyme-catalyzed depolymerization allows efficient recycling of poly(ethylene terephthalate) (PET) bottles, which are easy to sort and made of slowly crystallizing PET. However, because crystalline phases are recalcitrant to enzymatic hydrolysis, this technology fails for rapidly crystallizing polyester wastes such as poly(butylene terephthalate) (PBT), unsortable mixed polyesters, or heterogeneous formulated PET waste streams. We show that melt transesterification and vitrimerization of mixtures of rapidly crystallizing polyester wastes, leveraging catalysts already present, produce copolyesters that crystallize slowly and are readily depolymerized. For example, reactive blending of a rapidly crystallizing postindustrial PET nonwoven waste with PBT improves depolymerization yields from 20% (PET nonwoven) and 1% (PBT) to 90%. Synergistic mixing can replace sorting, extending the scope of enzymatic recycling to recalcitrant, heterogeneous, and unsortable wastes
Deep transcranial ultrasound stimulation using personalized acoustic metamaterials improves treatment-resistant depression in humans
No full textInternational audienceBackground: Neuromodulation of deep brain regions has shown promise for treatment-resistant depression (TRD). However, it currently requires neurosurgical electrode implantation, posing significant risks and limiting widespread use while TRD affects around 100 million people worldwide. Low-intensity transcranial ultrasound stimulation (TUS) could allow precise and non-invasive deep neuromodulation, provided that the challenge of the defocusing effects of the skull is tackled.Objective/hypothesis: Here, we present the development of a portable and neuronavigated TUS prototype based on the use of patient-specific metamaterials (metalens) that correct for skull-induced aberrations. We then present the first application of metalens-based Transcranial Ultrasound Stimulation (mTUS) in TRD. The primary objective was to assess the safety and efficacy of mTUS targeting on individual level specific white matter tracts of the subcallosal cingulate involved in TRD.Methods: The safety and precision of this device was addressed through a series of numerical simulations and experimental measurements on ex vivo human skulls. Five participants with TRD were included in this open-label study (ClinicalTrials.gov identifier: NCT06085950) and underwent an intensive 5-day course of mTUS with a total of 25 sessions of 5 min each.Results: No serious adverse events occurred during the study. By day 5 of treatment, depression severity was reduced by an average of 60.9 % (range: [30 %–83.9 %]), and four out of five patients qualified as responders, with two of them in remission.Conclusions: This study provides first-in-human evidence of the potential of mTUS as a precise, safe and effective non-invasive neuromodulation technique for neuropsychiatric disorders involving deep brain regions, offering a safer and more accessible alternative to invasive approaches
Quantitative tremor monitoring before, during and after MR-guided focused ultrasound thalamotomy for essential tremor with MR compatible accelerometers
No full textInternational audienceBackground: MR-guided focused ultrasound (MRgFUS) has been developed to treat essential tremor effectively and noninvasively. Currently, clinical examination is used to identify therapeutic efficacy during treatment, but MRgFUS surgery could benefit from real-time, rater-independent quantitative monitoring of tremor, such as accelerometry data. Methods: Fourteen patients with medically refractory essential tremor underwent MRgFUS thalamotomy. Patients were instructed to hold postures during treatment. Tremor was monitored during each ultrasonic thermal sonication with MR-compatible accelerometers. Real-time feedback based on tremor amplitude in the 2-20 Hz band was calculated to evaluate the efficacy of each thermal ablation. Results: On average 6 ± 2 ablative sonications only were required to induce improvement in tremor on the clinical rating scale for tremor (CRST) of 89 ± 11% at D + 7, 79 ± 12% at M + 1, 74 ± 19% at M + 3 and 72 ± 23% at M + 12. The overall predictive efficacy measured with accelerometry during the treatment was 70 ± 30%. The tremor amplitude reduction measured with accelerometry was correlated with CRST scores tremor reduction at multiple timepoints (ρ = 0.79 at D + 7, ρ = 0.75 at M + 1, ρ = 0.86 at M + 3, and ρ = 0.63 at M + 12) and accelerometric data gathered during treatment predicted CRST tremor improvement at M + 3 (0.88 area under ROC curve). Conclusion: This exploratory study is a proof of concept suggesting that accelerometry measurements can provide real-time feedback on tremor reduction and can complement visual evaluation. In the future, the use of the outcome prediction introduced in this paper may shorten procedure time and limit adverse events by reducing the number of ablative administered sonications
P-226 OWLO's new three-dimensional label-free imaging technology, applied to cumulus-oocyte complexes, reveals subcellular structures for quality assessment
No full textInternational audienceStudy question Can three-dimensional (3D) imaging improve oocyte evaluation for assisted reproductive technologies (ART)? Summary answer OWLO's high-resolution, label-free, ultrafast imaging allows the assessment of oocyte maturity through the identification of polar bodies and intracytoplasmic organites such as lipid droplets. What is known already There is a need to develop robust assessment tools, as higher quality oocytes have been shown to have higher blastocyst rates but also a higher chance of producing euploid embryos. Oocyte nuclear maturity cannot currently be assessed in non-ICSI IVF because cumulus cells prevent visualization of the polar body (PB). Morphological abnormalities in oocyte and zona pellucida (ZP) shape, PB and perivitelline space size or ooplasmic granularity, and changes in the lipid profile are known to be detrimental. However, phase-contrast microscopy used in clinical practice does not allow proper visualization of these structures, making it difficult to identify cytoplasmic abnormalities. Study design, size, duration In this proof-of-concept study, bovine oocytes were imaged for the first time using OWLO's 3D imaging prototype. The imaging prototype is a new technology under development that allows non-invasive 3D imaging without moving the sample in depth. It is based on a low energy near-infrared laser source and is label-free. Participants/materials, setting, methods Cumulus-oocyte complexes were collected from bovine ovaries obtained from a slaughterhouse, cultured in supplemented in vitro maturation medium for 22 hours, and fixed in 2% PFA. Some samples were centrifuged (7 min, 13400g) prior to fixation. Images were captured using the OWLO prototype, at a resolution of 0.3 × 0.3 × 1.74 µm, with an acquisition window large enough to capture the entire oocyte. Acquisition takes a few seconds and physics-based algorithms perform 3D reconstruction. Main results and the role of chance OWLO's imaging prototype and physics-based algorithms achieve high-resolution images in depth (500µm). These are the first label-free 3D images of oocytes done in an ultra-fast acquisition. The technology is successfully used to image through complex oocyte cumulus and identify the polar body. This is a straightforward marker of oocyte maturity that is in general not available in clinics. The imaging system's resolution also enables visualization of intracellular structures without requiring fluorescent labelling. In particular, the zona pellucida (ZP), trans-zonal projections (TZP) and lipid droplets were identified as the brightest elements of the image. To validate this, some samples were imaged after centrifugation, which concentrates lipids at the centripetal pole. Imaging both centrifuged and not centrifuged oocytes shows that the lipid profile can be identified on OWLO's images. Moreover the thickness of the ZP can be measured accurately, and TZPs can be identified and quantified. Vacuoles also appear as hypoechoic and can be easily identified. Further work will aim to gather evidence of mitochondrial abnormalities and presence of refractile bodies. Non-invasively visualizing and quantifying these intracellular structures opens new opportunities to assess oocyte quality in IVF treatments. Limitations, reasons for caution This is a preliminary study that provides promising results. Fluorescence imaging will be used to validate the identification of lipids and other subcellular structures. This study used bovine models only and will be extended to human oocytes in the future to validate the potential of this method. Wider implications of the findings OWLO's imaging technology is the first to allow non-invasive 3D imaging of oocytes without decoronization in a few seconds. This technological breakthrough can remove bottlenecks in oocyte quality assessment. It has also been successfully used to image early-stage embryos and blastocysts and could serve to assess their quality before embryo transfer. Trial registration number N
Chlorométhylation directe de liaisons C(sp<sup>3</sup>)-H par activation du CH₂Cl₂ à l'aide d'un plasma non thermique
No full textInternational audienceNon-thermal plasma has been implemented for chemical activation of CH₂Cl₂ in a continuous flow gas-liquid system operating at ambient temperature and pressure. In this study, we present a direct and catalyst-free approach for the chloromethylation of saturated hydrocarbons. The reaction test resulted in the functionalization of cyclohexane without a catalyst or additives, achieving a total yield of 30% of chlorinated products with a residence time of 60 s. The influence of substrate concentration, gas/liquid flow ratio, energy density and residence time was studied, which resulted in a proposal of reaction pathway where the reaction is initiated by the C-Cl dissociation in CH₂Cl₂ , followed by H-abstraction on C(sp3)-H and radical recombination. These mechanistic insights provide valuable knowledge for the advancement of plasma chemistry. Furthermore, the use of deuterated dichloromethane allows the introduction of deuterium into saturated hydrocarbons.Le plasma non thermique a été utilisé pour l’activation chimique du CH₂Cl₂ dans un système gaz-liquide en flux continu fonctionnant à température et pression ambiantes. Dans cette étude, nous présentons une approche directe et sans catalyseur pour la chlorométhylation des hydrocarbures saturés. Le test de réaction a permis la fonctionnalisation du cyclohexane sans catalyseur ni additifs, atteignant un rendement total de 30 % de produits chlorés avec un temps de séjour de 60 secondes. L’influence de la concentration du substrat, du ratio de flux gaz/liquide, de la densité énergétique et du temps de séjour a été étudiée, ce qui a conduit à une proposition de mécanisme réactionnel où la réaction est initiée par la dissociation C-Cl dans le CH₂Cl₂, suivie d’une abstraction d’hydrogène sur C(sp3)-H-H et d’une recombinaison radicalaire. Ces éléments mécanistiques apportent des connaissances précieuses pour le développement de la chimie plasma. De plus, l’utilisation du dichlorométhane deutéré permet l’introduction de deutérium dans les hydrocarbures saturés
Contrôle des nanoplaquettes semiconductrices II-VI, du cœur inorganique pour des propriétés optiques dans l'infrarouge, à la coque organique
No full textGroup II-VI semiconductor nanoplatelets are emerging as exceptional materials due to their precise atomic layer-controlled synthesis, leading to narrow photoluminescence and remarkable spectral tunability. This thesis investigates the modularity of NPLs through two main projects aimed at expanding their potential for optoelectronic applications.The first project introduces a cation exchange method catalyzed by Ag+, enabling the synthesis of HgxCd1-xSe NPLs with tunable photoluminescence in the near- and short-wave infrared range. This method achieves optical gain at 1.3 µm and reduces the activation energy of the cation exchange process, facilitating the fabrication of thicker NPLs while preserving morphology.The second project focuses on ligand exchange between carboxylates and thiolates on 3 ML CdSe NPLs. Using isotropic XRD measurements and detailed spectroscopic analyses, this study elucidates the impact of ligand exchange on the lattice structure, the reconfiguration of nanohelices, and optical properties. These insights provide a deeper understanding of the interplay between inorganic cores and organic ligands, paving the way for advanced NPL design.Les nanoplaquettes semi-conductrices du groupe II-VI s'imposent comme des matériaux exceptionnels grâce à leur synthèse contrôlée à l'échelle atomique, produisant une photoluminescence étroite et une accordabilité spectrale remarquable. Cette thèse explore la modularité des NPLs à travers deux projets principaux visant à étendre leur potentiel pour les applications optoélectroniques.Le premier projet développe une méthode d'échange cationique catalysée par Ag+, permettant de synthétiser des NPLs alliées HgxCd1-xSe avec une photoluminescence modulable dans l'infrarouge proche et moyen. Cette méthode atteint un gain optique à 1,3 µm et réduit l'énergie d'activation du processus d'échange cationique, facilitant la fabrication de NPLs plus épaisses tout en préservant leur morphologie.Le second projet se concentre sur l'échange de ligands entre carboxylates et thiolates sur des NPLs CdSe 3 ML. Grâce à des mesures XRD isotropiques et à des analyses spectroscopiques détaillées, cette étude met en lumière l'impact de l'échange de ligands sur la structure cristalline, la reconfiguration des nanohélices et les propriétés optiques. Ces résultats offrent une compréhension approfondie des interactions entre les cœurs inorganiques et les ligands organiques, ouvrant la voie à une conception avancée des NPLs
Metamodeling elastic wave propagation using a mixed factorized Fourier encoder-decoder for online laser-ultrasound testing in additive manufacturing
No full textSubmitted to Eng. Appl. Artif. Intell. the 24th October 2024International audienceLaser-ultrasound (LU) testing has emerged as a promising technique for characterizing the polycrystalline microstructure of metal components produced by wire-laser additive manufacturing (WLAM), with potential for real-time online application. Numerical models simulating elastic waves propagation provide valuable insights into the relationship between microstructural properties and laser-induced displacements, but their computational cost renders them impractical for automated high-throughput characterization. To overcome this limitation, we build a metamodel that maps a wide variety of two-dimensional anisotropic polycrystalline microstructures simplified but representative of features commonly observed in WLAM to simulated surface displacements. Addressing this challenging high-dimensional regression problem, several neural network surrogates are proposed. Their architectures include usual convolutional encoder-decoder elements and layers inspired from the Fourier neural operator (FNO) framework. Several variants of this novel combination are investigated. All metamodels can run both a forward and backward pass at least 100~times faster than a single forward call of the original model. Notably, the channel-wise factorized variant of the spectral layers, which is characterized by a relatively small number of parameters, achieved the lowest approximation error. The metamodel successfully captures the primary effects of anisotropy on wave propagation, even for low-anisotropy inputs not included in the training data. These findings represent a promising initial step towards addressing inversion problems and facilitating the development of online LU testing protocols in additive manufacturing
Rapid Enantiomeric Ratio Determination of Multiple Amino Acids Using Ion Mobility-Mass Spectrometry
No full textInternational audienceChiral analysis is becoming increasingly important across various scientific fields, including chemistry, pharmaceuticals, biosciences, and more recently, metabolomics. In this context, a high-resolution and high-throughput method was developed for the simultaneous determination of the enantiomeric ratio (er) of seven pairs of amino acid (AA) enantiomers (Arg, Gln, His, Met, Pro, Tyr, and Trp) using flow injection analysis coupled with ion mobility-mass spectrometry (FIA-IM-MS) technology. Specifically, the Single Ion Mobility Monitoring (SIM 2 ) mode on a TIMS-Tof TM instrument enabled the rapid relative quantification of chiral compound mixtures. A linear model accurately described the relationship between enantiomeric ratio and IM-MS response for Arg, Gln, and Pro enantiomers, as evidenced by high R 2 values and unbiased residuals. In contrast, non-linear trends were observed for His, Tyr, and Trp, where a quadratic model significantly improved the fit. However, the linear model was retained for Met, despite an R 2 of about 0.98, due to its comparable performance and simplicity. Measurement accuracy was confirmed with very good recovery rates for er values of 0.95 and 0.99 across all AAs. Finally, the potential of the FIA-SIM 2 -MS approach in chiral analysis was demonstrated, particularly its ability to provide a reliable and efficient high-throughput tool for accurate er determination
Seafoams associated with phaeocystis sp. bloom accumulate saprophytic and parasitic microorganisms from terrestrial origin
No full textInternational audienceThe community composition, structure, origin, and trophic functions of eukaryotic microorganisms on seafoam deposits (N = 30) and adjacent seawater (N = 32) were explored at the beach of Wimereux (North of France) during the Phaeocystis globosa spring bloom (March-May 2023), using high throughput sequencing of 18S rRNA marker gene. Our results notably showed that eukaryotic communities trapped in seafoams were different from communities in adjacent seawater. In particular, seafoams were rich in ASVs affiliated to saprobes and parasites compared to seawater, with a terrestrial origin for most of them