186 research outputs found

    Serious games en bibliothèque (Les)

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    Dossier d’accompagnement réalisé par des élèves conservateurs, pour la journée Serious game qu\u27ils ont organisée à l\u27enssib le 24 octobre 2012 dans le cadre de l\u27U.E. "Comprendre le numérique

    Feasibility of mechanical extrusion to coat nanoparticles with extracellular vesicle membranes

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    Biomimetic functionalization to confer stealth and targeting properties to nanoparticles is a field of intense study. Extracellular vesicles (EV), sub-micron delivery vehicles for intercellular communication, have unique characteristics for drug delivery. We investigated the top-down functionalization of gold nanoparticles with extracellular vesicle membranes, including both lipids and associated membrane proteins, through mechanical extrusion. EV surface-exposed membrane proteins were confirmed to help avoid unwanted elimination by macrophages, while improving autologous uptake. EV membrane morphology, protein composition and orientation were found to be unaffected by mechanical extrusion. We implemented complementary EV characterization methods, including transmission- and immune-electron microscopy, and nanoparticle tracking analysis, to verify membrane coating, size and zeta potential of the EV membrane-cloaked nanoparticles. While successful EV membrane coating of the gold nanoparticles resulted in lower macrophage uptake, low yield was found to be a significant downside of the extrusion approach. Our data incentivize more research to leverage EV membrane biomimicking as a unique drug delivery approach in the near future

    Experimental assessment of active electroacoustic absorbers for broadband room modes damping

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    Active electroacoustic absorbers are membrane absorbers actuated, through a feedback control loop and an electromechanical driver, so as to present optimal sound absorption on a broadband range around the membrane resonance. Taking advantage of the low resonance frequency of conventional loudspeakers, this technique appears as an interesting solution for the damping of low-frequency modes in rooms. This concept has direct applications to real life problems, such as the equalization of sound diffusion in the low-frequency range, or the mitigation of noise immission from external noise sources in habitations, among others. The performance of 4 prototypes of active electroacoustic absorbers is assessed inside a reverberant chamber with different sound stimuli (stationary broadband noise, pure tones). It is shown that the 4 electroacoustic absorbers prototypes, which represent only 0.1% of the total wall surfaces, achieve a global noise level attenuation of almost 8 dB, on a broad frequency range from 20 Hz up to 100 Hz, with individual mode attenuations up to 12 dB. Moreover, the modal decay times are significantly reduced, which is also verified with recordings of time-limited pure tones at several resonant frequencies in the room

    Talking parts, talking back

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    One of the greatest challenges of our times is that of lack of voice for abused bodies. These are the bodies of children and men and women who have inherited the brutalities of colonialism, plantation servitude and slavery and now re-live these miseries in the belly of a rampant global neoliberal and patriarchal capitalism. They are the racialized, sexualized, genderized and godless bodies that first took form in coloniality-modernity in conjunction with the emergence of MAN, the White, rational, disembodied male as HUMAN. They retain their shape today through technologies of vulnerability, with which the manufactured lack of voice works in dynamic synergy. This is particularly the case for South Africa, with its tender histories and distraught presents, raw emotion and sore vulnerabilities of racialized and neoliberal patriarchy. In this paper, we suggest that vulnerability, beyond its potentially devastating effect on souls and livelihoods, may also be a productive site for the articulation of alternative, and habitually silenced voices. In this regard, we explore how a focus on acts of Linguistic Citizenship may orientate thinking on voice and agency to different sites of the body, as well as allow insight into the complex technologies and practices of vulnerability

    Retinal atrophy, inflammation, phagocytic and metabolic disruptions develop in the MerTK-cleavage-resistant mouse model

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    In the eye, cells from the retinal pigment epithelium (RPE) facing the neurosensory retina exert several functions that are all crucial for long-term survival of photoreceptors (PRs) and vision. Among those, RPE cells phagocytose under a circadian rhythm photoreceptor outer segment (POS) tips that are constantly subjected to light rays and oxidative attacks. The MerTK tyrosine kinase receptor is a key element of this phagocytic machinery required for POS internalization. Recently, we showed that MerTK is subjected to the cleavage of its extracellular domain to finely control its function. In addition, monocytes in retinal blood vessels can migrate inside the inner retina and differentiate into macrophages expressing MerTK, but their role in this context has not been studied yet. We thus investigated the ocular phenotype of MerTK cleavage-resistant (MerTKCR) mice to understand the relevance of this characteristic on retinal homeostasis at the RPE and macrophage levels. MerTKCR retinae appear to develop and function normally, as observed in retinal sections, by electroretinogram recordings and optokinetic behavioral tests. Monitoring of MerTKCR and control mice between the ages of 3 and 18  months showed the development of large degenerative areas in the central retina as early as 4 months when followed monthly by optical coherence tomography (OCT) plus fundus photography (FP)/autofluorescence (AF) detection but not by OCT alone. The degenerative areas were associated with AF, which seems to be due to infiltrated macrophages, as observed by OCT and histology. MerTKCR RPE primary cultures phagocytosed less POS in vitro, while in vivo, the circadian rhythm of POS phagocytosis was deregulated. Mitochondrial function and energy production were reduced in freshly dissected RPE/choroid tissues at all ages, thus showing a metabolic impairment not present in macrophages. RPE anomalies were detected by electron microscopy, including phagosomes retained in the apical area and vacuoles. Altogether, this new mouse model displays a novel phenotype that could prove useful to understanding the interplay between RPE and PRs in inflammatory retinal degenerations and highlights new roles for MerTK in the regulation of the energetic metabolism and the maintenance of the immune privilege in the retina

    Admission criteria and management of critical care patients in a pandemic context: position of the Ethics Commission of the French Intensive Care Society, update of April 2021.

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    Intensive care unit professionals have experience in critical care and its proportionality, collegial decision-making, withholding or withdrawal of treatment deemed futile, and communication with patients' relatives. These elements rely on ethical values from which we must not deviate in a pandemic situation. The recommendations made by the Ethics Commission of the French Intensive Care Society reflect an approach of responsibility and solidarity towards our citizens regarding the potential impact of a pandemic on critical care resources in France, with the fundamental requirement of respect for human dignity and equal access to health care for all

    Community-Level Responses to Iron Availability in Open Ocean Plankton Ecosystems

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    Predicting responses of plankton to variations in essential nutrients is hampered by limited in situ measurements, a poor understanding of community composition, and the lack of reference gene catalogs for key taxa. Iron is a key driver of plankton dynamics and, therefore, of global biogeochemical cycles and climate. To assess the impact of iron availability on plankton communities, we explored the comprehensive bio-oceanographic and bio-omics data sets from Tara Oceans in the context of the iron products from two state-of-the-art global scale biogeochemical models. We obtained novel information about adaptation and acclimation toward iron in a range of phytoplankton, including picocyanobacteria and diatoms, and identified whole subcommunities covarying with iron. Many of the observed global patterns were recapitulated in the Marquesas archipelago, where frequent plankton blooms are believed to be caused by natural iron fertilization, although they are not captured in large-scale biogeochemical models. This work provides a proof of concept that integrative analyses, spanning from genes to ecosystems and viruses to zooplankton, can disentangle the complexity of plankton communities and can lead to more accurate formulations of resource bioavailability in biogeochemical models, thus improving our understanding of plankton resilience in a changing environment

    Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

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    Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly
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