Laboratoire Léon Brillouin

UMR12 CEA-CNRS, Bât. 563 CEA Saclay

91191 Gif sur Yvette Cedex, France

+33-169085241 llb-sec@cea.fr

Let's scatter neutrons

PhD subjects

3 sujets IRAMIS//LLB

Dernière mise à jour : 12-07-2020


• Molecular biophysics

• Radiation-matter interactions

• Soft matter and complex fluids

 

Functional amyloids, bacterial adaptation and new antibiotics

SL-DRF-20-1024

Research field : Molecular biophysics
Location :

Laboratoire Léon Brillouin

Groupe Biologie et Systèmes Désordonnés

Saclay

Contact :

Véronique ARLUISON

Starting date : 01-10-2020

Contact :

Véronique ARLUISON
Université de Paris - DRF/IRAMIS/LLB/GBSD

01 69 08 32 82

Thesis supervisor :

Véronique ARLUISON
Université de Paris - DRF/IRAMIS/LLB/GBSD

01 69 08 32 82

Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=varluiso

Laboratory link : http://www-llb.cea.fr/MMB/

In bacteria, the genetic material is often in a crowded and congested state. For instance, the size of the bacterial nucleoid, the structure that contains the bacterial chromosome associated with proteins, is typically sub-micron whereas the length of the DNA is around 1 mm. The genome is hence compacted by a factor of thousand. Expected breakthroughs of the PhD project are to develop and to couple methods for the investigation of nucleoprotein structures. A multidisciplinary approach will be developed at the Leon Brillouin laboratory in collaboration with a group at SOLEIL Synchrotron (DISCO beamline). The PhD student will investigate the e?ect of protein-mediated bridging on the structural properties of bacterial DNA. In particular, we aim to study a new way of DNA structuring by a bacterial protein forming amyloid structures, called Hfq. DNA condensation induced by amyloids associated to neuropathologies has been reported previously. Here the amyloid domain of Hfq serves the physiology of the cell to ensure DNA compaction. Examining the interaction of Hfq with DNA will thus be paramount for understanding bacterial nucleoid compaction and functional consequences. The expected bene?ts for this PhD project will be twice: the development of methods for the analysis of biological nanostructures, but also new opportunities for the development of antibiotics.

Coulomb phase in Rare-Earth hyperkagome networks

SL-DRF-20-0539

Research field : Radiation-matter interactions
Location :

Laboratoire Léon Brillouin

Groupe 3 Axes

Saclay

Contact :

SYLVAIN PETIT

Starting date : 01-10-2020

Contact :

SYLVAIN PETIT
CEA - DRF/IRAMIS/LLB/G3A

01 69 08 60 39

Thesis supervisor :

SYLVAIN PETIT
CEA - DRF/IRAMIS/LLB/G3A

01 69 08 60 39

Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=spetit

Laboratory link : http://www-llb.cea.fr/NFMQ/

The last decades in solid-state research have seen the rise of rich and novel physics, beyond the Néel paradigm and transcending conventional descriptions based on Landau theory. Frustrated magnetism has contributed to these developments in major ways, through new concepts like the “Coulomb phase”, a highly degenerate state of matter brought to light by the discovery of spin ice in rare-earth pyrochlore networks. In the following PhD proposal, our aim is to use hyperkagome networks of rare-earths to further explore and develop this new physics.



Enhanced poly(Ionic Liquid) lubricants: multiscale structure and interfacial properties

SL-DRF-20-1191

Research field : Soft matter and complex fluids
Location :

Laboratoire Léon Brillouin

Groupe de Diffusion Neutron Petits Angles

Saclay

Contact :

Alexis Chenneviere

Frédéric Restagno

Starting date : 01-09-2020

Contact :

Alexis Chenneviere
CEA - DRF/IRAMIS/LLB/GDNPA

0667677870

Thesis supervisor :

Frédéric Restagno
CNRS - Université Paris Saclay, Laboratoire de Physique des Solides, UMR 8502


Personal web page : http://iramis.cea.fr/llb/Phocea/Membres/Annuaire/index.php?uid=achennev

Laboratory link : http://www-llb.cea.fr/

Poly(Ionic Liquid) – PIL- refer to a special type of polyelectrolyte in which each monomer unit is composed of ionic liquid (IL). They have recently drawn significant attention since they present a unique combination of the properties of ILs (e.g.high thermal, chemical, electrochemical stabilities, interfacial adsorption and enhanced ionic conductivity) with those of polymer materials (e.g. processability, viscoelasticity, adhesion, film-forming properties, and broad macromolecular design...). On a polymer physicist point of view, the main difference between an ideal polymer melt and PILs stems from the presence of counter-ions and local interactions between IL monomer units due to their amphiphilic nature. Preliminary experiments involving small angle neutron scattering have highlighted the influence of these local interactions on the conformation of PILs chains leading to a deviation from ideal polymer chains conformation. Such a deviation has a strong influence on the bulk viscoelastic properties of PILs which may lead to enhanced lubrication properties. The aim of this PhD project is to understand the role of the macromolecular conformation both in bulk and at interface on the slippage of PILs at interfaces and determine the molecular parameters allowing to enhance lubrication.



In order to answer such question, we plan to combine structural characterization using neutrons and X-ray scattering techniques and slippage measurements using photobleaching based velocimetry measurements.

 

Retour en haut