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A Late Antique Dipinto in the Brigham Young University Collection
No full textInternational audienceThis article presents an edition of a Greek dipinto in the L. Tom Perry Special Collections at the Harold B. Lee Library, Brigham Young University. It preserves Christian phraseology, includes two isopsephies, mentions a (monastery) of St. Menas, and records that the content of the amphora was garum (“fish sauce”)
Fine-tuning mechanical constraints reveals uncoupled patterning and gene expression programs in murine gastruloids
No full textInternational audienceThe interplay between mechanical forces and genetic programs is fundamental to embryonic development, yet how these factors independently or jointly influence morphogenesis and cell fate decisions remains poorly understood. Here, we fine-tune the mechanical environment of murine gastruloids, three-dimensional in vitro models of early embryogenesis, by embedding them in bioinert hydrogels with precisely tunable stiffness and timing of application. This approach reveals that external constraints can selectively influence transcriptional profiles, patterning, or morphology, depending on the level and timing of mechanical modulation. Gastruloids embedded in ultra-soft hydrogels (< 30 Pa) elongate robustly, preserving both anteroposterior patterning and transcriptional profiles. In contrast, embedding at higher stiffness disrupts polarization while leaving gene expression largely unaffected. Conversely, earlier embedding significantly impacts transcriptional profiles independently of polarization defects, highlighting the uncoupling of patterning and transcription. These findings suggest that distinct cellular states respond differently to external constraints. Live imaging and cell tracking demonstrate that impaired cell motility underlies polarization defects, underscoring the role of mechanical forces in shaping morphogenesis independently of transcriptional changes. By allowing precise control over external mechanical boundaries, our approach provides a powerful platform to dissect how physical and biochemical factors interact to orchestrate early embryonic development
Oboo Cairns as A Support for Local Memory and Oral History Among the Pastoralists of Inner Mongolia
No full textInternational audienceOvoo/Oboo cairns are highly significant features of Inner Asia’s sacred landscape. In Inner Mongolia Autonomous Region (People’s Republic of China), oboo are not only a fundamental component of the natural landscape, they also serve as territorial markers and as support for local history. Indeed, every oboo possesses its own story, revealing the historical circumstances under which a group of people settled in a given locality and marked it as its own upon arrival by erecting a cairn. Since the mid-2000s and the inclusion of oboo worship on China’s national list of Intangible Cultural Heritage, local people have been concerned with restoring their oboo’s story. Elders, intellectuals, and other influential people in the communities have started to piece oral legends together with historical data. Based on ethnographic fieldwork conducted since 2011 among the pastoralists of Hulun Buir area, I will show that oboo cairns are a support for local memory and oral history that steer people’s sense of place and ethnic belonging in Inner Mongolia’s most multi-ethnic area
Environmental Changes and Cultural Practices : A Cross-Cultural Dialogue Between France and China
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Cell adhesion and spreading on fluid membranes through microtubules-dependent mechanotransduction
No full textInternational audienceIntegrin clusters facilitate mechanical force transmission (mechanotransduction) and regulate biochemical signaling during cell adhesion. However, most studies have focused on rigid substrates. On fluid substrates like supported lipid bilayers (SLBs), integrin ligands are mobile, and adhesive complexes are traditionally thought unable to anchor for cell spreading. Here, we demonstrate that cells spread on SLBs coated with Invasin, a high-affinity integrin ligand. Unlike SLBs functionalized with RGD peptides, integrin clusters on Invasin-SLBs grow in size and complexity comparable to those on glass. While actomyosin contraction dominates adhesion maturation on stiff substrates, we find that on fluid SLBs, integrin mechanotransduction and cell spreading rely on dynein pulling forces along microtubules perpendicular to the membranes and microtubules pushing on adhesive complexes, respectively. These forces, potentially present on non-deformable surfaces, are revealed in fluid substrate systems. Supported by a theoretical model, our findings demonstrate a mechanical role for microtubules in integrin clustering
Sister external tufted cells form dynamic intraglomerular ensembles representing odor identity and concentration
No full textInternational audienceHighlights• ETCs encode odor identity and concentration via dynamic neuronal ensemble activity• Increasing odor concentrations recruit sister ETCs in a structured, progressive manner• Sister ETCs form intraglomerular ensembles shaped by odor</div
Genre et sciences
No full textInternational audiencePendant des siècles, les femmes de science ont été invisibilisées, ignorées ou spoliées de leurs découvertes. Si le xxe siècle a vu évoluer la condition féminine en Occident, leur ouvrant l’accès aux études supérieures et aux métiers scientifiques, les femmes restent largement sous-représentées dans certains domaines des sciences et, d’une manière générale, dans la plupart des postes clés de la recherche et de l’ingénierie.Multiplier les approches pour mieux saisir la portée de ce déséquilibre en analysant la place du genre dans la science et le genre comme objet de science, avancer des pistes concrètes pour favoriser la diversité dans les sciences et la représentation équitable de tous les talents, garantes de la continuité de l’innovation : tel est le propos de cet ouvrage qui réunit à cet effet les textes de chercheuses et de chercheurs de disciplines variées, de l’histoire à la biologie en passant par les mathématiques, l’informatique, la sociologie, le droit, l’économie et la philosophie
The alpha7 nicotinic acetylcholine receptor mediates network dysfunction in a mouse model of local amyloid pathology
No full textInternational audiencePatient and animal model data suggest a link between the cholinergic neuromodulatory system and the amyloid beta (Aβ) peptide in causing Alzheimer's disease (AD). But how cholinergic dysfunctions contribute to AD pathology remains controversial. In a mouse model of local amyloid pathology, we show that in the early disease stages, the α7 nicotinic acetylcholine receptor (nAChR) is an important target of Aβ in the prefrontal cortex (PFC). Using in vivo two-photon calcium imaging and in vivo patch-clamp electrophysiology in the PFC of awake mice, we demonstrate that Aβ-mediated disruption of specifically the α7 nAChR subunit, expressed by distinct interneuron subtypes, results in substantial deficits in network activity. This is corroborated by electrophysiology experiments in slices. Combined with computational modeling, we propose that α7 nAChRs are occluded by Aβ early in the disease, whereas the heteropentameric α5 and β2 nAChRs are only partially inactivated and potentially provide novel therapeutic targets for intervention. Accordingly, we show that galantamine, an approved acetylcholine-esterase inhibitor (AChE-I), which acts as a positive allosteric modulator (PAM) of α5-containing nAChRs at low concentrations, reduces neuronal hyperactivity
Leaky or polarised immunity: Non-Markovian modelling highlights the impact of immune memory assumptions
No full textInternational audienceMathematical models tend to oversimplify the biological details of vaccine or infection-derived immunity effectiveness. Yet, epidemiological outcomes may diverge when assuming polarised immunity-individuals are either fully susceptible or completely immune-compared to leaky immunity-where all individuals are partially protected. We explore the differences between the two by taking advantage of a non-Markovian framework, which allows us to explicitly record the 'age' of the immunity and vary its effectiveness accordingly. A basic scenario reveals that leaky immunity leads to a shorter time between reinfections. A more data-driven scenario based on SARS-CoV-2 data finds that leaky immunity yields substantially more reinfections than polarised immunity and a higher number of infected individuals, yet with a lower probability of hospitalisation. Our findings emphasize the critical role of immune memory modelling assumptions, especially for long-term epidemiological dynamics and public health policies
Probing the water adsorption and stability under steam flow of Zr-based metal-organic frameworks using <sup>91</sup>Zr solid-state NMR spectroscopy
No full textInternational audienceThe stability of metal–organic frameworks (MOFs) in the presence of water is crucial for a wide range of applications, including the production of freshwater, desiccation, humidity control, heat pumps/chillers and capture and separation of gases. In particular, their stability under steam flow is essential since most industrial streams contain water vapor. Nevertheless, to the best of our knowledge, the stability under steam flow of Zr-based MOFs, which are among the most widely studied MOFs, has not been investigated so far. We explore it herein for three UiO-like Zr-based MOFs built from the same Zr cluster but distinct organic linkers at temperature ranging from 80 to 200 °C. We demonstrate the possibility of acquiring their 91Zr NMR spectra using high magnetic field (18.8 T) and low temperature (140 K) and of interpreting them by comparing experimental data with NMR parameters calculated by DFT. NMR observation of this challenging isotope combined with more conventional techniques, such as N2 adsorption, X-ray diffraction, IR, and 1H and 13C solid-state NMR spectroscopies, provides information not only on the possible collapse of the MOF framework but also on the adsorption of molecules into the pores. We notably show that UiO-66(Zr) and UiO-66-Fum(Zr) built from terephthalate and fumarate linkers, respectively, are stable over 24 h (and even over 7 days for UiO-66(Zr)) under steam flow at all investigated temperatures, whereas UiO-67-NH2 containing a 2-amino-[1,1′-biphenyl]-4,4′-dicarboxylate linker degrades under steam flow at temperatures ranging from 80 to 150 °C but is preserved at 200 °C. The lower stability of UiO-67-NH2 stems from its larger pores and its weaker Zr–O coordination bonds, whereas its preservation at 200 °C results from a more limited condensation of water in the pores