Post doctoral/Research engineer position in esophageal tissue engineering using bioprinting techniques
Due to disease such as cancer or accidents such as caustic burns, the esophagus is sometimes irreversibly damaged and the only option is to remove it and replace it by using the stomach and part of the digestive tract, which often leads to serious complications and even in the best cases to poor functional results and poor quality of life. The most advanced current developments in tissue engineering for the esophagus is the use of decellularized donor tissue and clinical trials are ongoing at St Louis Hospital in this area. This approach however still presents some limitations, in particular related to donor shortage and inflammatory response. In order to prepare the next generation approach, the lab initiated a project funded by MSD Avenir to build an esophagus substitute using 3D printing. This bottom-up approach which uses bioinks as a starting material allows full control over 3D architecture and the construct can be thus personalized to the patient’s morphology and pathology, including smaller sizes for pediatric patients, in unlimited supply which is a great advantage over donor tissue. We have patented a formulation based on both natural and synthetic polymers which shows similar mechanical properties when compared to native esophagi, good suturability as well as high porosity to allow cell colonization. It also presents slow degradation as the ultimate aim is that it be replaced with native regenerated tissue over time.
Profile
We are seeking a highly motivated and autonomous post-doctoral fellow or research engineer to continue this project and characterize long term culture on this scaffold by re-epithelializing the interior of the tube and seeding primary endothelial and muscular cells on the outer part. Characterizations will include both material mechanical testing and long term cell behavior, morphology and analysis of any toxicity.
Location; St Louis Hospital, Paris
Design of 2D Matrix For Silicum Quantum computing with Validation by Simulation
The objective is to design a 2D matrix structure for quantum computing on silicon in order to consider structures of several hundred physical Qubits.
In particular the subject will be focused on:
- The functionality of the structure (Coulomb interaction, RF and quantum)
- Manufacturing constraints (simulation and realistic process constraint)
- The variability of the components (Taking into account the variability parameter and realistic defectivity)
- The constraints induced on the algorithms (error correction code)
- Scalability of the structure to thousands of physical Qubits
The candidate will work within a project of more than fifty people with expertise covering the design, fabrication, characterization and modeling of spin qubits as well as related disciplines (cryoelectronics, quantum algorithms, quantum error correction, …)
Theoretical and experimental studies of the polarized light's propagation into OLED structure
In collaboration with chemists from CEA Saclay and the University of Rennes, Leti's LCEM laboratory is interested in new chiral molecules for OLED (Organic Light Emitting Device) sources able to emit circularly polarized light (CP). The interest of these CPOLED sources is multiple and encompasses both micro-screens and healthcare applications. While the state of the art is quite extensive on the chemical part, few studies have looked at the generation and transport of light in CPOLEDs components.Likewise, the conditions for measuring the polarity of the light emitted are not very detailed in the existing literature.
At the LCEM laboratory, where these chiral molecules are integrated into CPOLED devices, the goal is to design OLED architectures that can better preserve the polarization of light. To do this, it is essential to understand the propagation of light in OLED stacks from a theoretical and experimental point of view. This work is part of a larger collaboration set up in the ANR "i-chiralight" project.
In this context, we are proposing a study which will take place in two phases.
- Study of simple emitting materials: The materials to be studied will be thin layers deposited under vacuum using evaporation's system of thin layers available in the laboratory. The organic materials used will be supplied by our chemical partners in Saclay or Rennes. Optical characterizations such as ellipsometry,photoluminescence, etc. will be carried out in order to assess the performance of molecules in terms of emission efficiency but also in terms of the rotational power of light. For this last point, a model able to calculate all the terms of the Müller matrices is under development and the validation of this one will be a work to be carried out by the post-doctoral fellow.
- Study of complete OLED components: In the second phase of this work, we will focus on the complete OLED system by studying the propagation of optical modes in the stack of the different layers const
Experimentation and numerical simulation of lithium battery thermal runaway
In the current Energy transition context, the lithium battery is an essential technology to address the strong challenge of the electrical energy storage. However, Li battery severe solicitations/loadings can lead to a thermal runaway phenomenon, which can cause an outbreak of fire, even an explosive combustion of the cell or of the whole battery pack. If this phenomenon is well known, the research and development dedicated to the battery safety is emerging and must be consolidated. The post-doctorate global objective is to develop a numerical modelling and simulation strategy for thermal runaway occurring when a Li battery is subjected to mechanical/thermal/electrical abuse, in order to gain an understanding of the phenomenon, estimate the thermal spreading risk as a result of gas combustion, or study the runaway mechanical consequences (fluid structure interaction). This strategy relies on physical testing campaigns carried out as part of the post-doctorate, and on numerical tools developed by CEA (EUROPLEXUS, Cast3M). The work will be organised into three main content areas: Understanding and modelling of the phenomena on the basis of experimental tests (shock tube, abusive tests), Development of a numerical model representative of identified phenomena, Modelling including fluid-structure interaction (case deformation due to pressure increase).
Environmental dosimetry: study, design and implementation of a calibration facility for low dose equivalent rates
In order to meet the calibration needs of the European radioactivity monitoring network, the Laboratoire national Henri Becquerel, part of CEA List, is installing a calibration facility for low dose equivalent rates, below 1 µSv/h. The work includes a study of the performance of the existing radiation beams and the design, installation and dosimetric characterization of a shielded facility to reduce the radiative background, in which low activity photon sources will be installed.
Design of an embedded vision system integrating a fast intelligent imager
The goal of the postdoc is to evaluate the interest of smart imagers integrating processing in the focal plane in embedded vision systems for a localization function and to propose a complete embedded vision system integrating a smart imager and a host.
The study will focus on ego-localization applications, to realize, for example, a 3D localization function.
From an existing application chain, the post-doctoral fellow will be able to carry out an algorithmic study in order to optimize it to exploit the qualities of the intelligent imager.
Then he will be able to propose a partitioning between smart imager and host system, according to performance criteria.
An experiment using the RETINE smart imager as well as the IRIS host board could be conducted to validate the proposal.
Elaboration of a common robot/human action space
This post-doc aims at establishing by artificial intelligence methods (e.g. signal processing on graphs), the mapping of an industrial task performed by a human operator, and acquired by visual sensors, in order to be interpretable and exploitable by a robot. It is part of a project aiming at designing a demonstrator in which a robot will learn to reproduce by observation a task performed by a human. The platform has been deployed at CEA Tech and is currently operated by an engineer.
The objective of this post-doc is mainly to study and develop a set of methods to build a mapping between the actions performed by a human operator and perceived through visual sensors and the actions performed by the robot. These methods and the work of the related theses will then be implemented in the demonstrator in order to test them experimentally.
Due to the central position of the subject of this post-doc, under the triple supervision of the PACCE and IPI teams of LS2N and CEA, you will have to collaborate closely with the two PhD students already involved in the project. You will have to conceptualize and formalize the methods and representations on the one hand by synthesizing the existing literature on the subject and on the other hand by establishing a common framework encompassing the two thesis works.
Evaluation of RF system power consumption for joint system-technology optimization
To be able to increase and optimize wireless transmission systems based on a hybridization of technologies, it is strategic to be able to quickly evaluate the capabilities of these technologies and to adapt the associated architecture as best as possible. To this end, it is necessary to implement new approaches to global power management and optimization.
The work of this post-doctoral contract is at this level.
The first step will be to develop some new power consumption models of the RF transceivers building blocks (LNA, Mixer, Filter, PA, …). A modelization approach has already been tested and validated in the group. In the next step, it will be needed to link the performances of the overall wireless system to the building blocks characteristics. Lastly, the optimization will be applied thanks to an efficient solution. Lastly, the proposed approach will be validated in the optimisation of a multi-antenna millimeter wave wireless system. An evaluation methodology specific to 3D will also be put in place
Optomechanical force probes development for high speed AFM
The proposed topic is part of a CARNOT project aiming at developing a new generation of force sensors based on optomechanical transduction. These force sensors will be implemented in ultrafast AFM microscopes for imaging and force spectroscopy. They will allow to address biological and biomedical applications on sub-microsecond or even nanosecond time scales in force spectroscopy mode.
First optomechanical VLSI force probes on silicon have been designed and fabricated in LETI's industrial grade clean rooms and have led to first proofs of concept for fast AFM [1,2]. The post-doctoral student will be in charge of the preparation of force probes in order to integrate them in a high speed AFM developed by our partner at CNRS LAAS (Toulouse). He will be in charge of the back end operations, from the release of the structures, their observation (SEM, optical microscopies, etc.), to the optical packaging with fiber optic ferrules. He will also participate in the development of a test bench for components before and after packaging to select devices and validate the packaged probes before integration into an AFM.
The post-doctoral student will also investigate the operation of the probe in a liquid medium to allow later AFM studies of biological phenomena: for this, the development of efficient actuation means (electrostatic, thermal or optical) of the mechanical structure will be carried out and applied experimentally. A feedback on the modeling and the design is expected from the measurements, in order to ensure the understanding of the observed physical phenomena. Finally, the post-doctoral fellow will have the possibility to propose new device designs to target the expected performances. The devices will be fabricated in Leti's clean room, then tested and compared to the expected performances.