Water is by far the most important and most studied fluid of all times, but the physics of water confined at the nanoscale remains largely mysterious, despite its major implication in numerous fields. In the project COWAT, we aim at measuring for the first time the properties of water confined at the nanoscale inside an individual, narrow (? 1.4 nm) carbon nanotube. We will make use of the exquisite sensitivity of the nanotube mechanical resonators, down to a single proton, to characterize both the hydrogen bond network and the transport properties of water confined at the nanoscale. We will be able to answer several open question in the nanofluidic community, among which the origin of fast water flow inside narrow carbon nanotube.

In 2020, the principal investigator of this project introduced a proof technique with applications in many areas related to combinatorics. This proof technique relies on a counting argument and belongs to a family of techniques such as the Lovasz Local Lemma and entropy compression. These techniques are instrumental in proving the existence of combinatorial objects under specific constraints. They have found numerous applications in combinatorics on words, graph theory, tilings, group theory, and many other related areas. The most basic version of the counting argument yields bounds identical to one of the versions of entropy compression. Moreover, the proofs are considerably simpler, relying on elementary combinatorial arguments such as inductions and bijections. This simplicity has enabled the PI and others to push this argument further to solve open problems that resisted other known techniques. The objective of the project is to study the counting argument and some related techniques to improve their applications. The success of this project will be measured by the new problems we can solve by utilizing these techniques.

Our project aims to characterize the response of bee colonies to environmental disturbances. To do this, we will use instrumented hives allowing the real-time collection of physical and physiological data. This non-intrusive system will allow us to model colony response to environmental changes. Bees are eusocial insects with a unique biological duality, both as autonomous individuals and as elements of a colony considered a superorganism. Environmental stresses can destabilize colonies or even extinguish them. To better understand these mechanisms, we will measure in real time the physiological activity of hives through data such as mechanical vibrations, temperature, humidity and sound spectrum. We will complement these measurements with non-intrusive imaging devices in the visible and infrared spectrum. Our project is based on two major challenges: non-intrusive hive instrumentation and the management of massive data generated by our measurements, including their collection, storage, automation, processing and analysis. Next, we will tackle the interdisciplinary challenge of establishing a quantitative relationship between colony status and clearly identified environmental stressors, such as predator or parasite attacks, and variations in the outer conditions of the hive. The realization of this interdisciplinary project requires synergy between teams specialized in various fields: electronics, signal and image processing, modeling of the collective dynamics of interacting individuals, and the ethology of bees. Our results will help enrich our fundamental understanding and implement actions to prevent the disappearance of this species essential for the preservation of biodiversity.

Antimony (Sb) is one of the most enriched elements in urban environments but also the least studied. Given its potential toxicity, it is therefore very important to identify the impact of Sb on the environmental compartments accumulating this emerging contamination. Despite the fact that significant enrichments were registered in urban environment samples, important scientific issues remain totally unexplored, such as the relative contributions of the different sources of Sb contamination, and Sb biogeochemical behavior within and between urban sedimentary reservoirs. In this context, providing information about Sb speciation and transfer pathways is of prime importance in order to control the environmental dissemination of this emerging contaminant in the critical zone. The pluri-disciplinary ANTIMONY project will provide innovative knowledge on the sources and chemical forms of Sb in an urban continuum, from sources to receiving environmental compartments and this up to a long-time range. It proposes a progressive strategy made necessary by the complexity of the processes involved and by the lack of knowledge about the sources and the fate of Sb in urban areas. ANTIMONY is built in such a way as to explore the mechanisms governing Sb behavior at the molecular scale in controlled batch experiments, and to progressively increase the time and space scales of the experiments up to the study of long-term trends and impacts of Sb contamination on urban areas. Task 1 will examine the mechanisms of Sb mobilization in controlled conditions (T1 batch experiments). The number of potential processes (sorption/desorption of Sb species, biotic and abiotic redox transformations) require laboratory experiments in which processes are singled out for study: Sb(V) reduction to Sb(III) by pure bacterial strains or reductants produced by microbial activity (Fe(II), sulfides), ligand exchange from oxygen to sulfur, and oxidative stibnite dissolution. This comprehensive approach will generate novel "fundamental" information concerning the isotope fractionation and mineralogical changes accompanying the environmental and microbial processes that Sb is involved in. Task 2 is dedicated to retention ponds located along roads, which stand as model systems to study Sb transfers from car traffic areas to the aquatic environment. The partition of Sb in these environments, the Sb isotope ratio and the mineralogy of the bearing phases will be documented. Mesocosm experiments with sediments representative of urban reservoirs will be designed to gain insights into the processes affecting Sb mobility and to elucidate the role of bacteria in Sb transfer between water and sediment compartments. We will also use ?123Sb measurements as a probe to monitor the mechanisms involved at the molecular scale (oxidation, reduction, ligand exchange), allowing us to draw hypotheses on the changes in Sb geochemistry observed in the environment. We will take opportunity of this task to carry out isolation of pure or simplified bacterial consortia involved in Sb reduction. Task 3 will explore the behavior of Sb in the ‘road to the pond’ continuum during a rain event to reveal the fast changes in Sb behavior during heavy rain events which are suspected to transport a large part of the road to pond Sb fluxes. The analysis of other than road Sb source samples (e.g. paints, plastics, lead artefacts) will document the isotopic and spectroscopic signature of these sources. In Task 4, sediment archives will be collected in the Seine River Basin to document the influence of source changes vs. post-depositional processes on the Sb contamination trajectory during the last century in relation with diagenesis and source changes. During its course, ANTIMONY will provide sediment and DNA banking material for future studies devoted to Sb biogeochemical cycles and to other emerging contaminants, related to road traffic or not.

Osteoarthritis, a chronic degenerative joint disease, is one of the most common public health problems and one of the leading causes of pain and disability in adults over 65 years. Osteoarthritis is often diagnosed when the first symptoms appear (joint pain and loss of function), corresponding to an advanced stage of the disease when the joint is already irreversibly damaged. In this context, the identification of new tools appears necessary both for early diagnosis and for monitoring the progression and severity of the disease. The "single biomarker strategy" has demonstrated its limitations and the precision medicine for OA is now focusing on the identification of a panel of biomarkers that could better reflect a specific disease stage and predict its course over time. In this context, using an innovative targeted proteomics approach, we propose to assess the activation profile of several metalloproteinases (MMP and ADAMTS) in synovial fluids from OA patients with two distinct pathological profiles. Determining the activation state of these proteases directly involved in the degradation of the joint, as well as observing possible differences between their activation profiles according to the disease grade, will enable to identify functional biomarkers associated with the severity of OA. The specificity of the MP activation patterns identified at each grade will be also examined through a comparative analysis with synovial fluids from healthy subjects. Secondly, we propose to evaluate, in blood and urine, the presence of secondary biomarkers directly associated with the proteolytic activity of metalloproteases, namely the proteases identified in synovial fluids in complex with alpha macroglobulin. All these data should allow us to access an original set of predictive biomarkers, for a better description of the pathogenesis of OA.