Science

Research on “elastin-like” thermosensitive peptides

(Ref. LSS_5 )

This request is a continuation of a project that started successfully in April 2021]. Peptides called “elastin-like” (ELP) represent biological molecules resembling the hydrophobic units of elastin, a protein that confers elasticity to biological tissues such as the lungs, ligaments and blood vessels. These units can manifest a hydrophobic collapse by exceeding a certain temperature, a phenomenon called “lower critical solution temperature” (LCST). Due to their sensitivity to stimuli such as temperature, ELPs are used in areas such as biological materials and drug delivery. In addition to their physiological and medical revival, ELPs are also considered as models of disordered proteins having profound effects on cellular processes. Despite its pivotal role for the elasticity and sensitivity to external stimuli of ELPs, there is currently no mechanical characterization of the static and dynamic aspects of their hydrophobic collapse. In particular, the dynamic state in collapsed hydrophobic domains is a controversial issue. A deep understanding of the static and dynamic characteristics of ELPs is therefore of utmost importance. As part of this project, hydrogenated and deuterated ELPs using recombinant expression will be produced (protocol already established in the Life Sciences group of the ILL). They will then be purified by a method called “reverse temperature cycling” (ITC). Their pronounced temperature sensitivity has been demonstrated. ELPs were measured by light and neutron scattering in 2 SANS and QENS experiments at the Laue-Langevin Institute (ILL). Data analysis is in progress and the results will be published shortly. We are therefore currently looking for a trainee for the next steps of this project which will constitute a detailed characterization of phase diagrams and physicochemical parameters of ELPs. The intern will use static and dynamic light scattering, as well as calorimetry and optical spectroscopy. All these experiments will lead to the neutron experiments at the ILL after its restart at the end of 2022. Given the very promising results already obtained, we are sure to be able to continue and finish this project with excellent results.

Activities of the trainee:

The intern will establish and undertake the full range of project related tasks, including biosynthesis, experiments and data analysis. This internship will therefore allow the intern to become familiar with the process of generating scientific knowledge. Among the specific tasks are the recombinant expression of ELP based on a validated protocol is already applied; purification of ELPs using the ITC method; and the preparation and execution of experiments (light scattering, optical spectroscopy, calorimetry) with the samples produced. The project therefore unites the practical aspects of working in a chemical laboratory and biophysical analysis as well as data analysis. The most important aspect will be a good preparation of the neutron experiments at the ILL because the ELPs thus characterized will be the basis of these experiments after the restart of the ILL (end of 2022). The internship described here will start in September 2022.

Level required:

 Bac + 2 year university studies in biophysique

Language skills:

As an international research centre, we are particularly keen to ensure that we also attract applicants from outside France. You must be able to communicate in English or in French.

Notes:

This post is an internship with a maximum duration of 3 to 6 months

Benefits:

The internship allowance of between 555€ and 750€ (depending on profile and duration of the internship).

Please send your application directly to the supervisor

Olga MATSARSKAIA

mail: matsarskaia@remove-this.ill.fr

Investigation of structure and diffusion within supramolecular gels

(Ref. SPECT_2)

Supramolecular gels are a class of colloidal soft materials formed from the self-assembly of low molecular-weight gelators into a solid network of fibres that entrap and confine solvent. These gels have a range of applications, such as drug-delivery vehicles, crystallisation media, analyte sensors, light-responsive materials, catalysts, and tissue engineering substrates. For all of these applications, to create optimised gels detailed knowledge about the structure and dynamics of the gel-fibre network and its percolating solvent bulk are paramount. In this project you will work on characterising the materials properties of some new supramolecular gels and establish reliable gel setting protocols. Furthermore, you will perform experiments using pulsed-field gradient NMR spectroscopy and analyse neutron scattering data to understand the diffusion of solvent and solutes within the gels, and you will use UV-vis spectroscopy to monitor diffusion out of the gel with a view to developing drug delivery applications.

Activities of the trainee:

Working in the Partnership for Soft Condensed Matter laboratory, the trainee will use table-top pulsed field gradient-NMR and UV-Vis spectroscopy to monitor diffusion within and out of the gels. Other gel characterisation techniques to be employed include rheometry, DLS, Raman/IR spectroscopy, and fluorescence microscopy, where appropriate. The trainee will also analyse existing QENS data (which will offer the possibility to learn computational skills such as MatLab and Python). If neutrons become available for this project in December 2022, participation in neutron scattering experiments might be possible.

Level required:

4^th year university studies in physical or materials chemistry or related fields

Language skills:

As an international research centre, we are particularly keen to ensure that we also attract applicants from outside France. You must be able to communicate in English or in French.

Notes:

This post is an internship with a duration of 5 months

Benefits:

You will receive a monthly allowance of between 750 € and 900 €, depending on the duration of your internship and your profile.

Please send your application directly to the supervisor: Tilo SEYDEL email: seydel@remove-this.ill.eu

Neutron spectroscopy data analysis and rheology of proteins in crowded solutions

(Ref. SPECT_3)

Depending on the protein type and concentration, salt type and concentration, as well as on the temperature, aqueous solutions of proteins can display complex phase diagrams. These phases comprise fully dissolved regimes, so-called re-entrant dissolution regimes, as well as turbid and precipitate regimes and a liquid-liquid phase separation (LLPS). When transiting between different regimes, the protein dynamics is strongly affected by transient or static cluster formation and the possible entry into gel-like arrested states. The turbid and re-entrant regimes are assumed to be caused by and increasing charge-screening and ultimately inversion of the protein surface charge by the ions in the solution. The complex phase diagrams are being investigated since recently using neutron spectroscopy, and protein cluster formation has been observed as well as quantitatively modelled, depending on both the added salt [ M. Grimdaldo et al., J.Phys.Chem.Lett. 6, 2577 (2015) ] as well as on the crowding [ M.K. Braun et al., J.Phys.Chem.Lett. 8, 2590 (2017) ; C.Beck et al., J.Phys.Chem. B 122, 8343 (2018) ].The new project will continue these studies by exploring the entry into dynamically arrested states. Neutron spectroscopy data accessing this regime are already available from IN16B, and it is planned to carry out complementary rheology experiments in the PSCM.

Activities of the trainee:

The trainee will analyse existing neutron scattering data on concentrated protein solutions and carry out complementary rheology experiments in the PSCM.

Level required:

4^th year university studies in physics

Language skills:

As an international research centre, we are particularly keen to ensure that we also attract applicants from outside France. You must be able to communicate in English or in French.

Notes:

This post is an internship with a duration of 4 to 5 months

Benefits:

The internship allowance will be approximately 750 € (depending on profile and duration of the internship).

Please send your application directly to the supervisor Tilo SEYDEL mail: seydel@remove-this.ill.eu

Studying ceramics using neutrons: effects of production techniques

(Ref. SPECT_5)

Pore size distribution, pore shape and tortuosity, as well as the clay/inclusion ratio in volume percentage, of historical pottery depend strongly on the production techniques used and the geological sources. The aim of this project is to study ceramic fragments found in several geographic sites, using mainly neutron techniques, to correlate the characteristics of the ceramic porosity (in terms of total volume and pore dimensions, to specific production techniques. In particular we used neutrons to measure total porosity in samples of pottery produced in the late Holocene period from two ethnic groups in two regions of North Patagonia (Argentina) (Río Negro valley and foothills of the Somoncura plateau), as a new line of evidence for evaluating (in the Holocene) the probable causes of ethnic diversity.

This research can help to solve the debate about the determinacy of environmental adaptation and ethnic identity for understanding human diversity. During most of the twentieth century, the archaeological variability of Patagonian hunter-gatherers was interpreted as a result of ethnic diversity.

This perspective dramatically changed when "new archaeology" and "evolutionary ecology" emerged in academic circles at the beginning of the 1980s. At this point local adaptations and evolution became the main concepts for explaining archaeological diversity; ethnic differentiation was completely disregarded. Nowadays, and in the light of new and more sophisticated methods (e.g. 87Sr/86Sr isotope analysis, and ancient DNA studies) it is becoming clear that both adaptation and ethnic variation were central factors of social (and archaeological) variability.

Using neutrons as a non-destructive technique, we intend to define an analytical procedure capable of distinguishing and linking the influences of local production techniques to the final product.

The neutron measurements taken will be supplemented with standard lab techniques such as mercury intrusion porosimetry (MIP) [a destructive technique], scanning electron microscopy (SEM) and traditional x-ray computed tomography (X-ray CT). 

Activities of the trainee:

The trainee will be involved in the analysis of neutron data collected on D16, using the SASVIEW software package, containing a comprehensive list of form factor models and also of shape-independent models (e.g. fractals). The trainee will also be involved in possible ancillary experiments on the samples using the resources present at ILL.

Level required:

5^th year university studies in physics, chemistry or materials science

Language skills:

As an international research centre, we are particularly keen to ensure that we also attract applicants from outside France. You must be able to communicate in English or in French.

Notes:

This post is an internship with a duration of 6 months

Benefits:

You will receive a monthly allowance of approximately 900 €, depending on the duration of your internship and your profile.

Please send your application directly to the supervisor: Claudia MONDELLI email: mondelli@remove-this.ill.fr

Experimental testing of cryogenic and sample preparation equipment for the HighNESS project

(Ref. NPP_4)

The aim of the European project HighNESS ("Development of High Intensity Neutron Sources at the ESS") is to enhance the intensities of cold, very cold and ultra-cold neutrons (CN, VCN and UCN) for future applications in fundamental physics and condensed matter research.

The ILL is involved in this project through the design of a novel source for ultra-cold neutrons (UCN).

Activities of the trainee:

The trainee will be involved in the testing and development of experimental components that will be used for scattering and transmission experiments with a prototype moderator. These will include cryostats, choppers and neutron optical devices.

Level required;

2^nd year university studies in physics (scientific computing)

Language skills:

As an international research centre, we are particularly keen to ensure that we also attract applicants from outside France. You must be able to communicate in English or in French.

Notes:

This post is an internship with a duration of 3 to 6 months

Benefits:

You will receive a monthly allowance of between 555 € and 650 €, depending on the duration of your internship and your profile.

Please send your application directly to the supervisor: Richard WAGNER, wagnerrichard@remove-this.ill.fr

Optimisation of high-precision and high-stability magnetic field shaping for the PanEDM experiment

(Ref. NPP_6)

The aim of the PanEDM experiment is to improve - by two orders of magnitude - sensitivity for the measurement of a permanent electric dipole moment (EDM) of the neutron. This would contribute to the ongoing search for beyond-Standard Model physics that could explain the matter/antimatter asymmetry arising from CP-violating interactions in the early universe.

The experiment relies on several technological advancements, including exceptional magnetic shielding, a non-magnetic composite vacuum chamber, highly stable ultra-cold neutron detectors, novel optical magnetometers, and a delicate ultra-cold neutron guiding system. The experiment is being implemented at the new SuperSUN instrument that is currently being built by the NPP group at the ILL.

The magnetic environment is one of the crucial aspects to be controlled, as this removes the need for a co-magnetometer, which can be a sensitivity-limiting component. The magnetic field for the experiment is provided by six layers of passive mu-metal shielding, a system of 44 coils for the holding field (B0) and a similar set of coils for the spin-flip pulses (B1). Furthermore, a degaussing system for the mu-metal layers and an active monitoring system for magnetic field drifts in time and for field inhomogeneities are necessary to achieve the required magnetic field quality. The main parts of the magnetic field system are already installed and student contributions are now required to produce a magnetic field mapping robot to characterise the B0 and B1 fields and a system to monitor the magnetic environment. Specifically, the trainee will be tasked with the implementation of an optical setup to determine and monitor the orientation of the magnetic field robot.

This internship will build on the work undertaken during a 2021 internship, which already laid the foundations for this work.

This internship provides the trainee with an opportunity to take part in the ongoing development of the magnetic environment for a high-precision experiment and to collect, prepare and analyse experimental data with large potential benefit for the PanEDM collaboration and for nEDM physics in general. This internship is intended to be used for the student’s Master’s thesis at his/her home university.

Activities of the trainee:

• Refinement of the creation of the guide field (B0) and magnetic pulse (B1).
• Characterisation of the magnetic field environment inside the ultra-low field region of PanEDM using a field mapper and optical magnetometer that have been implemented at the ILL and at the Technical University of Munich (TUM).
• Analysis of experimental data and comparison to a simple field simulation.

Level required:

4th year university studies in physics or related subjects

Language skills:

As an international research centre, we are particularly keen to ensure that we also attract applicants from outside France. You must be able to communicate in English or in French.

Notes:

This post is an internship with a duration of 3 months

Benefits:

You will receive a monthly allowance of between 750 € and 900 €, depending on the duration of your internship and your profile.

Please send your application directly to the supervisor:

Olivier ZIMMER

email: zimmer@remove-this.ill.fr

Optimisation of production and characterisation of polypropylene foils for SuperSUN

(Ref. NPP_8)

SuperSUN, a new instrument at the ILL, produces ultracold neutrons by inelastic scattering in superfluid helium at temperatures of 0.5-0.6K. Ultracold neutrons (UCN) move so slowly that they can be stored in material bottles for many minutes, in contrast to the more commonly used cold and thermal neutrons which traverse an experiment in a fraction of a second. UCN are used in the experiment PanEDM to search for a permanent electric dipole moment (EDM) of the free neutron, which would be an indication of beyond-Standard Model physics that potentially explains the matter/antimatter asymmetry arising from CP-violating interactions in the early universe. To reach the required UCN storage times in PanEDM, it is necessary to create a high-quality vacuum below 10-6 mbar inside a unique glass-fiber composite vacuum chamber. This is connected directly to SuperSUN, which requires a vapour pressure due to liquid helium in on the order of 10-4 – 10-5 mbar.

This internship focuses on producing and characterising ~1 micron thick polypropylene foils, to be used for a neutron-transmitting vacuum barrier between SuperSUN and PanEDM. Such foils simultaneously protect the PanEDM storage cells from contamination by helium from SuperSUN, and protect SuperSUN from long-term degradation due to the freezing-in of atmospheric gases. Preliminary tests with this type of foil indicate improvements in source performance and an acceptable transmission loss of UCN. Depending on the regulations at the home university of the student, this internship can be used for a Master’s thesis.      

Activities of the trainee:

- Develop a reproducible process to produce thin polypropylene foils with the requires geometry and supports

- Residual gas and leak analysis of the PanEDM and SuperSUN vacuum systems, including the composite vacuum chamber

- Optimisation of the thickness of the foil

- Characterisation of the mechanical properties of the foil.      

Level required:

4^th year university studies in physics

Language skills:

As an international research centre, we are particularly keen to ensure that we also attract applicants from outside France. You must be able to communicate in English or in French.

Notes:

This post is an internship with a duration of 6 months

Benefits:

You will receive a monthly allowance of between 750 € and 900 €, depending on the duration of your internship and your profile.

Please send your application directly to the supervisor:

Estelle CHANEL

email: chanele@remove-this.ill.fr

Design of a vacuum chamber for the Gas-Filled-Magnet device at FIPPS

(Ref. NPP_10)

FIPPS (Fission Product Prompt gamma-ray Spectrometer) is a new instrument of the Institut Laue-Langevin, consisting of an array of high-purity Ge detectors used for high-sensitivity spectroscopic studies coupled to an intense thermal neutron beam. The instrument is to be used for the study of the structure of neutron-rich nuclei produced in thermal neutron induced reactions on actinide targets.

A future upgrade of the instrument is planned, coupling the HPGe device to a Gas-Filled-Magnet separator for the identification of the fission fragments. A chamber containing the actinide target must be designed which satisfies both the physics requirements and the radiation protection safety regulation.

Activities of the trainee:

The trainee will perform the conceptual design of a vacuum chamber for the Gas-Filled-Magnet separator at FIPPS. S/he will evaluate the optimal configuration which satisfies radiation protection requirements while preserving the optimal conditions for gamma-ray spectroscopy studies (low attenuation for low-energy gamma-rays, low n-induced reaction cross-section, etc.).

Level required:

4^th year university studies in physics

Language skills:

As an international research centre, we are particularly keen to ensure that we also attract applicants from outside France. You must be able to communicate in English or in French.

Notes:

This post is an internship with a duration of 3 months

Benefits:

You will receive a monthly allowance of approximately 750 €, depending on the duration of your internship and your profile.

Please send your application directly to the supervisor:

  Caterina Michelagnoli

email: cmichela@remove-this.ill.fr

Structure of neutron-rich nuclei produced in fission experiments

(Ref. NPP_12)

Fission is the mechanism that can be used to populate nuclei far from stability and study their structure. By detecting gamma rays from excited fission fragments and analysing multiple gamma-ray coincidences, it is possible to reconstruct the nuclear level scheme. A number of campaigns have taken place in recent years at the ILL using n-induced fission and different experimental setups at the FIPPS instrument. The analysis of this data is important both for determining nuclear structure and for evaluating instrument performance.

Activities of the trainee:

The trainee will evaluate the performance of FIPPS in different fission campaigns. S/he will analyse multiple sets of gamma-ray coincidence data for reconstructing level schemes in neutron-rich nuclei.

Level required:

5^th year university studies in physics

Language skills:

As an international research centre, we are particularly keen to ensure that we also attract applicants from outside France. You must be able to communicate in English or in French.

Notes:

This post is an internship with a duration of 6 months

Benefits:

You will receive a monthly allowance of approximately 900 €, depending on the duration of your internship and your profile.

Please send your application directly to the supervisor:

  Caterina Michelagnoli

email: cmichela@remove-this.ill.fr

Spectral analysis of the incoherent structure function

(Ref. THEORY_1)

Quasielastic neutron scattering (QENS) has proved to be a key technique for studying the local dynamics of biomolecules (proteins, membranes, etc.) on pico to nanosecond time scales. The important and measurable quantity in QENS experiments is the incoherent structure function (ISF) (which is a function of the neutron scattering vector Q and time t). The analysis of the ISF allows us to extract all the information on the dynamics of the dynamically observable atoms and the characterisation of the system under investigation. In the majority of biological systems, the ISF is a complex function of Q and non-exponential variation as a function of t. The complexity of the ISF stems from the dynamics of the (hydrogen) atoms, which results from the hierarchical combination of different motions at different spatial scales and relaxation times. In practice, this multidimensional nature of the ISF means that the analysis of QENS data is confined to a few dynamic systems models from which the ISF can be approximated a priori.

The aim of this work is to develop a dimensionality reduction analysis of the ISF which makes it possible to correlate the amplitudes and relaxation times of the ISF with the dynamic characteristics of the system being investigated. As a first approach, we intend to investigate the feasibility of using multivariate statistical methods of Principal Component Analysis (PCA) to analyse the ISF on both the Q and time scales.

Activities of the trainee:

1 – Review (briefly) the literature on dimensionality reduction methods and their application to neutron data 

2 – Apply Principal Component Analysis to analyse the incoherent structure functions of neutrons

Key words: local dynamics, incoherent structure function of neutrons, PCA

Level required:

4^th or 5^thyear university studies in physics

Language skills:

As an international research centre, we are particularly keen to ensure that we also attract applicants from outside France. You must be able to communicate in English or in French.

Notes:

This post is an internship with a duration of 3 to 6 months

Benefits:

You will receive a monthly allowance of between 750 € and 900 €, depending on the duration of your internship and your profile.

Please send your application directly to the supervisor:

Dominique BICOUT

email: bicout@remove-this.ill.fr