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Extracellular vesicles released by tumors (tEVs) disseminate via circulatory networks and promote microenvironmental changes in distant organs favoring metastatic seeding. Despite their abundance in the bloodstream, how hemodynamics affect the function of circulating tEVs remains unsolved. We experimentally tuned flow profiles in vitro (microfluidics) and in vivo (zebrafish) and demonstrated that efficient uptake of tEVs occurs in endothelial cells subjected to capillary-like hemodynamics. Such flow profiles partially reroute internalized tEVs towards non-acidic and non-degradative Rab14-positive endosomes, at the expense of lysosomes, suggesting that endothelial mechanosensing diverts tEVs from degradation. Subsequently, tEVs promote the expression of pro-angiogenic transcription factors in flow-stimulated endothelial cells and favor vessel sprouting in zebrafish. Altogether, we demonstrate that capillary-like flow profiles potentiate the pro-tumoral function of circulating tEVs by promoting their uptake and rerouting their trafficking. We propose that tEVs contribute to pre-metastatic niche formation by exploiting endothelial mechanosensing in specific vascular regions with permissive hemodynamics.

Insect herbivores co-occurring on the same host plant interact in various ways. In particular, early-season insect herbivory triggers a wide range of plant responses that can determine the performance of herbivores colonizing the plant later in the course of the season. But the strength and direction of such effects are debated, and virtually unknown in the case of novel interactions involving exotic insects in their introduction range. We conducted an observational field study in SW France, a region recently invaded by the Oak Lace Bug (OLB,Corythucha arcuataSay). We measured early chewing damage and subsequent OLB damage in four oak species (Quercus robur, Q. pubescens, Q. cerrisandQ. ilex). We set up a complementary non-choice experiment in the laboratory, feeding OLB with leaves with or without prior herbivory. The four oak species differed in their sensitivity to OLB damage,Q. ilexbeing broadly resistant. Prior herbivory promoted OLB damage in the laboratory experiment, but not in the field. However, prior herbivory did not alter the rank of oak resistance to the OLB. Our results suggest possible synergistic effects between spring defoliators and the OLB. This study brings insight into herbivore-herbivore interactions and their possible implications for forest management.

International audience

Invasive, non-native invasive pests pose a growing threat to urban trees and the services they provide to urban residents. With the reluctance to use chemical insecticides in cities, environmentally friendly methods of pest management are needed. Tree diversity is known to affect insect herbivory in forest, with higher tree species diversity leading to lower level of damage. However, the validity of those findings for a non-native insect in an urban environment remains to be demonstrated.We monitored 54 horse chestnut trees attacked by the invasive horse chestnut leafminer Cameraria ohridella in the city of Bordeaux, France. We analyzed the effects of neighboring tree diversity and density on the abundance, damage and parasitism rate of these leafminers.We showed that the abundance and damage of C. ohridella significantly increased with higher local tree canopy cover. We found that the parasitism rate of C. ohridella increased with the species diversity of neighboring trees. However, this increase in parasitism rate was not associated with a decrease in leaf area damaged.Our results pave the way for the management of exotic insect pests in cities based on the manipulation of spatial distribution and species diversity of urban trees.

International audience; Magnetic Resonance Imaging is used here to study four phenomena: two-phase water/oil flow in porous media, rheology of fiber suspensions, natural convection in complex fluids and water diffusion in polymer membranes. These studies required the use or development of appropriate devices to maintain controlled external conditions in terms of mechanical stress, temperature or humidity. This article focuses on the instrumentation and methods used to perform MRI measurements on these systems.; L'Imagerie par Résonance Magnétique est utilisée ici pour l'étude de quatre phénomènes : l'écoulement diphasique eau/huile dans des milieux poreux modèles, le cisaillement de suspensions de fibres, la convection dans des fluides complexes et la diffusion de l'eau dans des membranes polymères. Ces études ont nécessité l'utilisation ou le développement de dispositifs adaptés, permettant de maintenir des conditions externes contrôlées en termes de contrainte mécanique, température ou hygrométrie. Cet article met l'accent sur l'instrumentation et les méthodes mises en oeuvre pour mener à bien des mesures d'IRM sur ces systèmes.

International audience; h i g h l i g h t s The influence of the PTL properties on the electrolyzer performance was investigated. Optimal performance was obtained for an average pore size of 10 mm and porosity of 31%. The pressure influence on the mass transport limitations was proved. Current density heterogeneities were observed with a segmented PEM electrolyzer. A new model for the constriction resistance in the catalyst layer was developed. Porous transport layer Segmented electrolyzer Mass transport limitations a b s t r a c t A titanium Porous Transport Layer (PTL) is usually used at the anode side of PEM water electrolyzers to ensure both the gas/water transport and the electric charges transfer. In this paper, four different sintered Ti powder PTLs were characterized to determine some properties, such as the pore size distribution, the porosity, and the permeability. Their influence on the electrolysis performance was investigated by using a 30 cm 2 segmented cell which allowed measuring the current density distribution, while controlling temperature and pressure conditions. For a better understanding, in-situ techniques such as the Polarization Curves and the Electrochemical Impedance Spectroscopy (EIS) were used. A local characterization of mass transport limitations caused by oxygen saturation was carried out, paying special attention to the pressure influence when using a PTL with very small pores. The results showed that current density heterogeneities can be explained by microstructure changes along the PTL. The optimal geometric characteristics of the PTL depend not only on the operating conditions such as current density, pressure, and temperature but also on the catalyst layer properties. A new model for the constriction resistance between the catalyst layer and the PTL was proposed. ScienceDirect j ou rnal h ome pag e: www.elsevier.com/loca te/he i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 4 5 (2 0 2 0) 8 0 9 4 e8 1 0 6

Following chemotherapy, a mediastinal germ cell tumor can lead to a mature teratoma that is composed of tissues derived from all three germ layers. Although teratoma is usually curable, in rare cases it can give rise to various somatic tumors and exceptionally it undergoes melanocytic neuroectodermal tumor (MNT) transformation, a process that is not well-described. We report a patient with a postchemotherapy thymic teratoma associated with an MNT component who, 10 years later, additionally presented a vertebral metastasis corresponding to an anaplastic MNT. Using exome sequencing of the mature teratoma, the MNT and its metastatic vertebral anaplastic MNT components, we identified 19 somatic mutations shared by at least two components. Six mutations were common to all three components, and three of them were located in the known cancer-related genesKRAS(p.E63K),TP53(p.P222X), andPOLQ(p.S447P). Gene set enrichment analysis revealed that the melanoma tumorigenesis pathway was enriched in mutated genes including the four major driver genesKRAS,TP53,ERBB4, andKDR, indicating that these genes may be involved in the development of the anaplastic MNT transformation of the teratoma. To our knowledge, this is the first molecular study realized on MNT. Understanding the clinicopathological and molecular characteristics of these tumors is essential to better understand their development and to improve therapeutics.

Aktuell polarisiert die Zukunft der „Freifläche“ am Wiener Naschmarkt in den Medien.Kaum ein Thema spaltet die Meinungen so sehr wie die Zukunft der Parkplatzfläche des Wiener Naschmarktes.Die einen wünschen sich eine großzügige Grün- und Freifläche, die anderen eine überdachte Markthalle.Wie kann ein so prägnanter und innenstadtnaher Ort am besten genutzt werden, um für die Bevölkerung und das Stadtklima einen Mehrwert zu schaffen?Das Wiental, auch „Grünes Tor“ der Stadt genannt, ist eine lineare Stadt- landschaft, die sich auf rund 14 Kilometern Länge von der westlichen Wiener Stadtgrenze bis zur Wienflussmündung in den Donaukanal bei der Urania quer durch die Stadt Wien zieht. Dabei bietet das Wiental einen Querschnitt durch die wesentlichen Gebietstypen Wiens und zeichnet heute eine der bedeutsamsten städtischen Achsen aus. Dank der Wienflussregulierug nach Plänen von Otto Wagner, ermöglichten die Wienflussüberwölbungen das Bebauen solch prägnanter innerstädtischen Bauplätze, wie den des Wiener Naschmarktes.Der Fluss die „Wien“ gibt der Stadt Wien nicht nur ihren Namen, sondern erfüllt dabei auch eine wesentliche Funktion für das Stadtklima als Frischluftschneise.Durch eine erneute Verlängerung des Wienfluss-Wegs/Wientalradwegs am Flussufer entlang bis zur Parkplatzfläche am Wiener Naschmarkt, kann ein qualitativ hochwertiger Stadtraum entstehen, der beruhigt vom Individualverkehr, eine Erweiterung des dürftigen und für alle Stadtbewohner*innen so notwendigen innenstadtnahen Freiraum ergibt.Diese Diplomarbeit stellt einen Entwurfsvorschlag dar, der unter Berücksichtigung des Klimas, die Interessen aller Wiener*innen miteinbezieht und dabei die sozialen Aspekte der Architektur und den qualitativ hochwertigen Freiraum entlang des Wienflusses berücksichtigt., Curently,the future of the „open space“ at Vienna‘s Naschmarkt is polarizing the media. Hardly any other topic divides opini-ons as much as the future of the par-king area of the Vienna Naschmarkt. Some want a generous green and open space, others a covered market hall. How can such a prominent location close to the city center best be used to create added value for the popula-tion and the urban climate? The Wiental, also known as the „Green Gate“ of the city, is a linear urban landscape that stretches across the city of Vienna on a length of about 14 kilometers from the western city limits to the mouth of the Vienna River into the Donau Canal near the Urania. Thereby, the Wiental offers a cross-section of the essential area types of Vienna and today distinguis-hes one of the essential urban axes. Thanks to the regulation of the Vien-na River according to plans by Otto Wagner, the Vienna River overarching vaults made it possible to build on such striking inner-city building sites as the Vienna Naschmarkt. The river the „Wien“ not only gives the city of Vienna its name, but also ful-fills an essential function for the city climate as a fresh air corridor. By a renewed extension of the Wien-fluss- Weg/Wientalradweg along the river bank to the parking area at the Vienna Naschmarkt, a high quality urban space can be created, which, calmed down from the individual traffic, results in an extension of the scarce and for all city dwellers so ne-cessary inner city open space. In this thesis, I would like to make a design proposal that incorpora-tes the interests of all while taking into account the climate, the social aspects of architecture and quality open space along the Vienna River.

Nous présentons ici une étude sur le gonflement d'hydrogels polymériques super-absorbants. L'IRM est utilisée pour suivre au cours du temps le gonflement de billes d'hydrogel plongées dans des solutions aqueuses contenant un agent de contraste. L'effet de ce dernier est examiné soigneusement car il peut influencer fortement la cinétique de gonflement des billes d'hydrogel.

International audience; The etiopathogenesis of critical COVID-19 remains unknown. Indeed given major confounding factors (age and comorbidities), true drivers of this condition have remained elusive. Here, we employ an unprecedented multi-omics analysis, combined with artificial intelligence, in a young patient cohort where major comorbidities have been excluded at the onset. Here, we established a three-tier cohort of individuals younger than 50 years without major comorbidities. These included 47 “critical” (in the ICU under mechanical ventilation) and 25 “non-critical” (in a non-critical care ward) COVID-19 patients as well as 22 healthy individuals. The analyses included whole-genome sequencing, whole-blood RNA sequencing, plasma and blood mononuclear cells proteomics, cytokine profiling and high-throughput immunophenotyping. An ensemble of machine learning, deep learning, quantum annealing and structural causal modeling led to key findings. Critical patients were characterized by exacerbated inflammation, perturbed lymphoid/myeloid compartments, coagulation and viral cell biology. Within a unique gene signature that differentiated critical from non-critical patients, several driver genes promoted critical COVID-19 among which the upregulated metalloprotease ADAM9 was key. This gene signature was supported in a second independent cohort of 81 critical and 73 recovered COVID-19 patients, as were ADAM9 transcripts, soluble form and proteolytic activity. Ex vivo ADAM9 inhibition affected SARS-CoV-2 uptake and replication in human lung epithelial cells. In conclusion, within a young, otherwise healthy, COVID-19 cohort, we provide the landscape of biological perturbations in vivo where a unique gene signature differentiated critical from non-critical patients. The key driver, ADAM9, interfered with SARS-CoV-2 biology. A repositioning strategy for anti-ADAM9 therapeutic is feasible.

When the water inventory evaporates during a hypothetical loss of coolant accident in the core of a pressurized water reactor, the fuel rods temperature increases substantially, resulting in the clad ballooning and the formation of blocked sub-channels. During the reflooding phase, where water is injected into the core and a steam-droplets flow is created above the water level, the presence of ballooned zone forces the steam flow to redistribute towards intact sub-channels, which degrades the cooling of ballooned clads within blocked sub-channels. Looking to better understand this flow redistribution process, this study presents experimental results of magnetic resonance velocimetry measurements of three-component velocity fields in several 49-element ballooned bundles to evaluate geometric effects (blockage ratio, length and coplanarity) on the flow dynamics, as well as the flow rate effect (Reynolds number from 1,936 to 9,599). The flow redistribution occurred in the transition zone upstream of the balloon. Moreover, the transverse velocities at this location are higher for higher blockage ratios and they can reach nearly the same magnitude of the axial velocity. The amount of deviated flow is approximately equal to the sub-channel’s blockage ratio and is virtually insensitive to the blockage length or the flow rate. Furthermore, the flow’s axial velocity reduces up- and downstream of blocked sub-channels and this reduction is more substantial as the blockage ratio increases. Results with non-coplanar balloons showed that a less intense flow redistribution takes place; however, a downstream balloon can affect the flow redistribution dynamics caused by an upstream ballooned zone. Finally, for all the tested bundles and tested flow rate ranges, the flow was remarkably homogenized by the downstream mixing spacer grid, restricting the clad ballooning effects only to the portion between the two spacer grids where the ballooned zone is located regardless of the balloon geometry and the flow rate. The present results may be useful as well for other research areas involving flow blockages in heat exchangers.