ERC FUNDED PROJECTS

Rupture of Aortic Aneurysms (AA), which kills more than 30 000 persons every year in Europe and the USA, is a complex phenomenon that occurs when the wall stress exceeds the local strength of the aorta due to degraded properties of the tissue. The state of the art in AA biomechanics and mechanobiology reveals that major scientific challenges still have to be addressed to permit patient-specific computational predictions of AA rupture and enable localized repair of the structure with targeted pharmacologic treatment. A first challenge relates to ensuring an objective prediction of localized mechanisms preceding rupture. A second challenge relates to modelling the patient-specific evolutions of material properties leading to the localized mechanisms preceding rupture. Addressing these challenges is the aim of the BIOLOCHANICS proposal. We will take into account internal length-scales controlling localization mechanisms preceding AA rupture by implementing an enriched, also named nonlocal, continuum damage theory in the computational models of AA biomechanics and mechanobiology. We will also develop very advanced experiments, based on full-field optical measurements, aimed at characterizing localization mechanisms occurring in aortic tissues and at identifying local distributions of material properties at different stages of AA progression. A first in vivo application will be performed on genetic and pharmacological models of mice and rat AA. Eventually, a retrospective clinical study involving more than 100 patients at the Saint-Etienne University hospital will permit calibrating estimations of AA rupture risk thanks to our novel approaches and infuse them into future clinical practice. Through the achievements of BIOLOCHANICS, nonlocal mechanics will be possibly extended to other soft tissues for applications in orthopaedics, oncology, sport biomechanics, interventional surgery, human safety, cell biology, etc.

1 999 396 €

Start date: 2015-05-01, End date: 2020-04-30

Quantum effects have been studied on photon propagation in the context of quantum optics since the second half of the last century. In particular, using single photon emitters, fundamental tests of quantum mechanics were explored by manipulating single to few photons in Hanbury-Brown and Twiss and Hong Ou Mandel experiments. In nanophysics, there is a growing interest to translate these concepts of quantum optics to electrons propagating in nanostructures. Single electron emitters have been realized such that single elementary electronic excitations can now be manipulated in the analog of pioneer quantum optics experiments. Electron quantum optics goes beyond the mere reproduction of optical setups using electron beams, as electrons, being interacting fermions, differ strongly from photons. Contrary to optics, understanding the propagation of an elementary excitation requires replacing the single body description by a many body one. The purpose of this proposal is to specifically explore the emergence of many body physics and its effects on electronic propagation using the setups and concepts of electron quantum optics. The motivations are numerous: firstly single particle emission initializes a simple and well controlled state. I will take this unique opportunity to test birth, life and death scenarii of Landau quasiparticles and observe the emergence of many-body physics. Secondly, I will address the generation of entangled few electrons quantum coherent states and study how they are affected by interactions. Finally, I will attempt to apply electron quantum optics concepts to a regime where the ground state itself is a strongly correlated state of matter. In such a situation, elementary excitations are no longer electrons but carry a fractional charge and obey fractional statistics. No manipulation of single quasiparticles has been reported yet and the determination of some quasiparticle characteristics, such as the fractional statistics remains elusive.

1 997 878 €

Start date: 2015-10-01, End date: 2020-09-30

Cells must move and position internal components to perform their function. We here focus on the physical designs which allow microtubule (MT) asters to exert forces in order to move and position themselves in vivo. These are arrays of MTs radiating from the centrosome, which fill up large portions of cells. They orchestrate nuclear positioning and spindle orientation for polarity, division and development. Forces that move asters are generated at nanometer and second scales by MT-associated motors from sites in the cytoplasm or at the cell surface. How MTs and force-generators self-organize to control aster motion and position at millimeter and hour scales is not known. We will use a suit of biophysical experiments and models to address how aster micro-mechanics contribute to aster migration, centration, de-centration and orientation in a single in vivo system, using the early stages of Sea urchin development as a quantitative model. We aim to: 1) Elucidate mechanisms that drive aster large-scale motion, using sperm aster migration after fertilization during which asters grow and move rapidly and persistently to the large-egg center. We will investigate how speeds and trajectories depend on boundary conditions and on the dynamic spatial organization of force-generators. 2) Implement magnetic-based subcellular force measurements of MT asters. We will use this to understand how single force-events are integrated at the scale of asters, how global forces may evolve will aster size, shape, in centration and de-centration processes, using various stages of development, and cell manipulation; and to compute aster friction. 3) Couple computational models and 3D imaging to understand and predict stereotyped division patterns driven by subsequent aster positioning and aster-pairs orientation in the early divisions of Sea urchin embryos and in other tissues. This framework bridging multiple scales will bring unprecedented insights on the physics of living active matter.

2 199 310 €

Start date: 2015-07-01, End date: 2020-12-31

Thermophotonic (TPX) coolers and generators based on electroluminescent (EL) cooling have the potential to enable a high efficiency replacement for thermoelectric devices. Highly optimized TPX devices can even outperform modern compressor based household refrigerators and heat pumps, enabling a significant reduction in the global energy consumption of cooling and heating. While the EL cooling phenomenon is theoretically well understood, it was only very recently demonstrated for the first time under very small power conditions. Enabling high power EL cooling, however, will require a breakthrough in reducing the losses present in conventional light emitting diodes (LED). iTPX aims to enable this breakthrough by developing an alternative approach to enhance the efficiency of light emission. The approach is based on enclosing the emitter-absorber pair used in TPX in a single semiconductor structure forming an optical cavity. This enhances the light emission rate by an order of magnitude and provides a substantial increase in the efficiency as well as several other technical and fundamental benefits. The main goal of iTPX is to demonstrate high power EL cooling for the first time and to provide quantitative insight on the limitations and possibilities of the cavity-based approach. Recent studies have shown extremely high – over 99 % – internal and external quantum efficiencies of light emission from optically pumped semiconductor structures. This suggests that the material quality of common III-V compound semiconductors is perfectly sufficient for EL cooling if similarly performing electrically injected structures can be fabricated in the single cavity configuration.

1 981 250 €

Start date: 2015-10-01, End date: 2020-09-30