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Harmonic imaging for tracking live human stem cells in whole blood at high-flow speed and GHz pixel rate
No full textInternational audiencePreclinical validation of the safety of cell therapy-based strategies requires precise monitoring of the biodistribution of transplanted cells within the host organism. Indeed, the detection of cells in the circulatory system as well as the identification of any possible aggregation state provide critical insights. However, this task demands deep penetration, fast imaging, high selectivity, subcellular resolution, and high throughput.In this study, we demonstrate and characterize a multiphoton-based in-flow detection method for live human stem cells in whole blood (unfiltered or diluted) using a microfluidic channel. Various experimental conditions are investigated such as laser power, stem cell concentration in blood, and flow rate. The approach is based on nonlinear optical microscopy with diffractive scanning perpendicular to the flow direction, enabled by a rapidly wavelength-swept laser.Stem cells were labeled with lithium niobate (LNO) harmonic nanoparticles (HNPs), which exhibit both second and third harmonic generation (SHG and THG). The combination of this setup and HNP-labeled cells enabled imaging at 4,000 frames per second with a pixel dwell time of 2.5 ns. Automated HNP-labeled cell detection and segmentation allowed extraction of key parameters such as single cell diameter, velocity, and recognition between single cells and aggregates.This combination of high-speed multiphoton microscopy and sensitive HNP labeling of cells in opaque and dense media offers a promising platform for detecting specific cells in the bloodstream under intravital microscopy, paving the way for evaluating the safety and dissemination of novel therapeutic agents
Swine influenza A virus infection sets the local immunological landscape in subsequent infection with porcine reproductive and respiratory syndrome virus
No full textInternational audienceAbstractFarmed pigs are frequently exposed to respiratory infections, with swine influenza A virus (swIAV) and porcine reproductive and respiratory syndrome virus (PRRSV) being key drivers. Most co-infection studies with these viruses have focused on PRRSV infection followed by swIAV. However, the reverse scenario, where swIAV is given first and then PRRSV, has not been explored. This infection sequence is plausible under natural conditions and warrants further study, especially given that influenza A virus has been shown in mice to impair alveolar macrophages, which are the target cells for PRRSV. This study aimed to evaluate the impact of swIAV infection on the alveolar macrophage population, clinical signs, immune responses, and viral loads during a secondary infection with PRRSV initiated 7 days after the initial swIAV exposure. Results demonstrated that primary swIAV infection did not exacerbate the clinical progression of PRRSV infection, nor did it result in significant differences in PRRSV loads or affect the alveolar macrophage population in the lungs of super-infected pigs as compared to those of pigs infected with PRRSV alone. However, swIAV pre-infection was associated with an increase in the number of conventional dendritic cells type 1 (cDC1), perforin-expressing T cells and NK-related lymphocytes in bronchoalveolar lavage. This coincided with an increase of PRRSV-specific IFN-γ producing CD4 T cells in blood detected 7 days post-PRRSV infection. These findings suggest that a swIAV infection could enhance immune responses during subsequent PRRSV infection by recruiting cDC1 and inducing IL-12, promoting a type-1 immune response, highlighting the complex interplay and often unexpected outcomes of viral co-infections occurring in close temporal proximity
Theileria equi, un complexe d'espèces ? Impact diagnostic
No full textInternational audienceLa piroplasmose équine, transmise par les tiques, est causée par deux parasites, Theileria equi et Babesia caballi, qui se multiplient dans les hématies (globules rouges) des équidés engendrant des problèmes d’un point de vue sanitaire et économique. La caractérisation génétique de ces espèces repose essentiellement sur l'analyse du gène codant l'ARNr 18S qui est peu variable mais permet de séparer cinq groupes de variants génétiques (génotypes) chez T. equi. Afin d’affiner cette caractérisation, des gènes conservés et variables de chacun des trois génomes présents chez ces parasites (noyau, apicoplaste et mitochondrie) ont été étudiés.Les comparaisons des séquences de ces gènes ont révélé que la variabilité intra-génotype est extrêmement faible. Par contre, on observe des variations entre génotypes plus ou moins importantes selon le gène étudié.Notre étude révèle également que certains tests actuellement utilisés pour diagnostiquer la piroplasmose équine peuvent conduire à des faux négatifs, en fonction du génotype présent chez le cheval
Steam reforming of main tar compounds over industrial gasification char
No full textInternational audienceBiomass gasification, including the gasification of waste, is a mature technology where biomass particles are converted mainly into a combustible gas called producer gas. However, cleaning the producer gas remains a significant challenge. This study tests multiple chars produced from an industrial gasifier, a pilot-scale gasifier, and a lab pyrolysis reactor for their efficiency in removing naphthalene, ethylbenzene, and toluene. Moreover, the study evaluates the impact of reforming environment (N 2 and synthetic syngas with/without steam) and temperature (650 • C, 750 • C). At 750 • C and in the absence of a catalyst, switching the carrier gas from N 2 to synthetic syngas enhanced the toluene and naphthalene removal efficiencies significantly. The catalyst impact was more pronounced at 650 • C, with the best-performing char characterized by a high surface area (1454 m 2 g -1 ) and ash content (10.15 wt%). In absence of steam, the tar content was reduced from 39.9 g Nm -3 to 24.3 g Nm -3 . Introducing steam further reduced the outlet tar content to 11.7 g Nm -3 . Utilizing gasification char for tar reforming not only adds value to waste but also aligns with the circular economy principles. This process enhances the quality of producer gas with the aid of a sustainably sourced catalyst. Remarkably, the char was used in its original form without modification, yet demonstrated exceptional performance in tar reforming
Performance d’une colonne de lavage vis-à-vis des particules de fumées d’incinération : étude expérimentale au sein d’une usine d’incinération
No full textWet scrubbers are among the most used industrial flue gas treatment devices. Although effective at absorbing acidic gases, wet scrubbers are not designed to capture submicronic particles. However, laboratory studies have shown that it is possible to improve their fine particle collection efficiency by adjusting operating conditions. In this thesis, the performance of wet scrubbers for collecting particles was evaluated under real conditions of a waste incineration plant at two scales: (i) by operating a downscaled wet scrubber fed with real flue gases from the incineration of household waste, and (ii) by quantifying the particle collection efficiency of an industrial scrubber at a hazardous waste incineration plant. CFD numerical simulations were performed to design the downscaled system and analyze the flow patterns inside the scrubbers. A parametric study was conducted to investigate the influence of operating conditions on the performance of the downscaled scrubber. The results showed that reducing the droplet diameter and increasing the liquid/gas flow ratio improved particle collection across all sizes. No influence of gas residence time was observed. The mechanistic collection models tested overestimate the results under real operating conditions. The performance of the industrial scrubber for collecting particles was found to be nearly zero/negative due to reaction and transfer phenomena between the droplets, the gases, and the particlesParmi les dispositifs de traitement des fumées les plus utilisés, figurent les laveurs à pulvérisation. Bien qu'efficaces pour absorber des gaz acides, les laveurs à pulvérisation ne sont pas conçus pour capturer les particules submicroniques. Toutefois, des études en laboratoire ont montré qu'il est possible de collecter davantage de particules fines en ajustant leurs conditions opératoires. Dans cette thèse, la performance de collecte des particules par les laveurs à pulvérisation a été évaluée dans des conditions réelles d’une usine d’incinération de déchets à deux échelles : (i) en exploitant un laveur à échelle réduite alimenté par des fumées réelles de l’incinération de déchets ménagers, et (ii) en quantifiant l'efficacité de collecte des particules d’un laveur industriel d’un site d’incinération de déchets dangereux. Des simulations numériques CFD ont été réalisées pour dimensionner le dispositif à échelle réduite et analyser l'écoulement à l'intérieur des laveurs. Une étude paramétrique a été conduite pour étudier l'influence des conditions opératoires sur les performances du laveur à échelle réduite. Les résultats indiquent que la réduction du diamètre des gouttelettes et la hausse du rapport entre les débits liquide/gaz améliorent la collecte des particules de toute taille. Aucune influence du temps de séjour du gaz n'a été constatée. Les modèles mécanistiques de collecte testés surestiment les résultats dans les conditions réelles d’exploitation. Les performances de collecte des particules du laveur industriel se sont avérées quasi nulles/négatives, en raison de phénomènes réactionnels et de transferts entre les gouttelettes, les gaz et les particules
The SAFFI project: fostering alignment and collaboration in EU-China food safety management with infant food safety as case study
No full textInternational audienceEnsuring food safety is a shared priority for both the European Union (EU) and China, yet differences in regulatory frameworks, enforcement mechanisms, and risk assessment approaches present challenges for harmonization. The SAFFI project (2020–2024), which concluded recently, seeked to bridge these gaps by fostering collaboration in food safety management, with a specific focus on infant food safety. Bringing together partners from several EU member states and Chinese provinces, SAFFI aimed to improve hazard identification, risk ranking, detection methods, and mitigation strategies for both microbial and chemical contaminants in infant food supply chains.This article first provides a comparative analysis of EU and Chinese food safety regulations, highlighting key similarities and differences in legal structures, risk assessment procedures, and enforcement strategies. Infant food safety standards are particularly strict in both regions, yet inconsistencies in testing methods, contaminant limits, and monitoring approaches necessitate greater alignment.The second part of the article details the scientific advances achieved through SAFFI to support regulatory convergence. These include structured databases and decision-support tools for hazard identification and prioritization, improved processing and preservation techniques for contaminant control, and cutting-edge analytical methods for detecting and monitoring known and emerging chemical and microbial hazards. The project also examined the role of consumer practices in mitigating risks and explored pathways for integrating rapid detection technologies into food safety systems.Overall, the outcomes of SAFFI contribute to enhanced consumer protection, the promotion of safe international trade, and the development of more coherent, science-based food safety policies through sustained EU–China cooperation
The Role of Sympathetic Neurotransmitters in Regulating Neutrophil Functions in Mammalian Models
No full textInternational audienceThe bi-directional crosstalk between the sympathetic nervous system (SNS) and the immune system is essential for maintaining homeostasis in animal organisms. During stress responses, the SNS releases catecholamines, such as norepinephrine (NE), often co-released with neuropeptide Y (NPY). Both NE and NPY can modulate response. However, their combined effects on immune cells like neutrophil granulocytes (NG) and potential species-specific differences remain poorly understood. NGs play a crucial role in immune-to-brain communication during systemic inflammation due to their ability to form neutrophil extracellular traps (NETs). Notably, excessive NET formation can elicit pro-inflammatory cytokine profiles, potentially inducing blood-brain-barrier leakage, leading to brain inflammation and neuronal damage. This study investigates the effects of NE and NPY on neutrophil-to-brain interactions using rat, human and porcine models.Bone marrow derived neutrophils from adult rats were incubated with the inflammatory stimuli group B streptococcus lysates (MOI 100) or lipopolysaccharide (LPS, 10μg/ml), as well as NE (1 μmol/l) and NPY (1 μmol/l), for 3h, both individually and in combination. Following treatment, the supernatants were analysed for TNF-a and IL-6 using bioassays. The cell cultures were fixed for immunofluorescence analysis using DAPI as a nuclear marker, as well as the NET markers myeloperoxidase (MPO) and DNA/histone1 to quantify NET induction.Our first results indicate that NE and NPY inhibited GBS-induced NETosis and GBS/LPS-induced cytokine production, suggesting an anti-inflammatory potential of NPY and NE. Ongoing and future work includes co-cultures of NGs or their stimulated supernatants with primary neuro-glial cell cultures, along with multimodal assessments such as immunofluorescence, RT-PCR, Western-Blot, multiplex assays, bioassays and transcriptomics
Effects of quality management on well-being at work and performance in a research laboratory: an exploratory study
No full textInternational audiencePurpose Over the past 20 years, more and more research organizations have chosen to integrate quality management into their strategic objectives, the principles and tools of which have long been deployed in private enterprises. The primary objective of quality management is to enhance the value of research activities and to demonstrate the traceability of data obtained and the reliability of published results. But have research laboratories been sufficiently prepared, and are they using quality management to steer their organizations toward achieving the objectives and satisfying the quality criteria of assessment organizations? Design/methodology/approach This research is based on the first author’s professional experience and on a survey of 235 participants from research laboratories to study the links between quality management, well-being at work and empowering leadership. Findings The results confirm that quality management improves the performance of a research laboratory and well-being at work, with managerial know-how being the key factor. Originality/value Organizational and individual levers are proposed to facilitate the involvement of people in the deployment and leadership of quality management
Enzyme-grafted nylon membranes for sequential filtration of Tetraselmis chui extract with enhanced protein recovery
No full textInternational audienceMicroalgae are considered a promising and sustainable source for valuable biomolecules such as proteins. Extraction of proteins from microalgae suspensions by membrane technology is still limited by fouling and inefficient recovery due to the complex mixture of biomolecules. In this work an enzyme-modified nylon microfiltration membrane was prepared to efficiently recover proteins from an extract of the microalgae Tetraselmis chui using a simple sequential filtration setup. A mixture of hydrolytic enzymes, trypsin and a lipase, was successfully grafted onto flat-sheet membranes using an electron beam-based approach. It was shown that for generating high lipase activity, co-immobilization with trypsin or another protein is beneficial. A design of experiments approach was used to determine the effect size of selected parameters for the sequential filtration process. Derived empirical models were used for optimization and confirmed by experiments resulting in protein recovery within the filtrate of up to 1.4 g/L marking a significant increase compared to 0.8 g/L with the commercial reference membrane. Furthermore, up to 40 % of the total protein content from the microalgae dry matter could be recovered, compared to 24 % with the reference membrane. The sequential filtration was found to be advantageous compared to direct filtration allowing a combination of both enzymatic incubation and filtration. Various characterization methods were performed showing that the enzyme grafting layer reduces fouling
Comment prendre en charge les tendinopathies de l’épaule selon les recommandations HAS ?
No full textInternational audienceRotator cuff disorders are a frequent reason for medical consultation. As they often impair patients’ work productivity, they represent a major societal cost. Given the frequency and cost of these disorders, optimal patient management appears essential to minimize their consequences. However, a recent survey carried out in France in 2022, showed an incomplete medical management in a significant proportion of patients with rotator cuff tendinopathy when they underwent acromioplasty. To improve this, French Health Authority established new recommendations to help practitioners diagnose painful shoulders and manage rotator cuff tendinopathy. These recommendations are based on a literature review and international guidelines. In this review, we present the key points of these recommendations.Les pathologies de la coiffe des rotateurs sont un motif fréquent de consultation. Elles touchent en particulier les patients actifs et leur impact sur la vie professionnelle représente un coût sociétal majeur. Vu la fréquence de la pathologie et son coût, une prise en charge optimale des patients semble essentielle pour en limiter les conséquences. Or, selon une enquête de pratique réalisée en France en 2022, la prise en charge médicale d’une proportion importante de patients atteints de tendinopathie de la coiffe des rotateurs était incomplète au moment où ils subissaient une acromioplastie. Pour améliorer la prise en charge de ces patients, la Haute Autorité de santé a donc rédigé de nouvelles recommandations pour guider le diagnostic devant une épaule douloureuse ainsi que la prise en charge thérapeutique des tendinopathies de la coiffe. Ces recommandations se basent sur une revue de la littérature et sur les recommandations internationales. Dans cette mise au point, nous rapportons les éléments essentiels de ces recommandations