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Portail > Offres > Offre USR3461-REGOPR-017 - Imageries avancées multi-échelles pour l'étude des matériaux de la paléontologie: application aux motifs colorés résiduels de gastéropodes fossiles. (H/F)

Postdoctoral position : Photoluminescence of porphyrins to REveal preServed color markER in post-paleozoic Vetigastropoda (PRESERV project) . (M/F)

This offer is available in the following languages:
Français - Anglais

Date Limite Candidature : mardi 10 novembre 2020

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General information

Reference : USR3461-REGOPR-017
Workplace : GIF SUR YVETTE,GIF SUR YVETTE
Date of publication : Tuesday, October 20, 2020
Type of Contract : FTC Scientist
Contract Period : 18 months
Expected date of employment : 1 December 2020
Proportion of work : Full time
Remuneration : Between 2728 and 3881 € gross monthly depending on experience
Desired level of education : PhD
Experience required : Indifferent

Missions

The European Photonic Institute for Non-Destructive Analysis of Ancient Materials (IPANEMA, site of the Synchrotron SOLEIL, University Paris-Saclay) is recruiting a post-doctoral researcher (M/F).

The post-doctoral researcher (physics-chemistry, M/F) will be in charge of studying the preservation of organic biochromes preserved within the shell matrix of fossil gastropod specimens. The aim will be to better specify the chemical interactions between the biochromes and the organic and inorganic fractions composing the shell. The systems studied will be made up of fossil and current specimens.

The 18-month research contract is funded by the Major Domain of Interest Matériauc anciens et patrimoniaux (DIM-MAP) of the Ile de France region.

The PRESERV (Photoluminescence of porphyrins to REveal preServed color markER in post-paleozoic Vetigastropoda) project is part of an emerging theme aimed at understanding the evolution of biochrome/color/vision relationships in the living world. It focuses on the Gastropods group which, by associating an extraordinary diversity of colors in current shells and an abundance of residual biochromes in fossil shells, offers a unique opportunity to study the evolution of these biochromes over time. Work initiated by our team allows us to show an unexpected preservation of biochromes at the molecular scale and over geological time. Starting from these first results in the course of publication, the PRESERV project aims at characterizing the evolutionary trajectory of porphyrinic dyes in post-Paleozoic Vetigastropods through two main axes: characterizing the interaction between porphyrinic biochromes and the shell matrix, which allowed their exceptional preservation over more than 150 million years, by developing an original coupling of separative chemical analysis approaches with UV visible spectral imaging. The second axis aims at defining the intra- and interspecific variability of the molecular structures of biochromes from a large corpus of current and fossil specimens of Vetigastropoda, in order to evaluate their potential as phylogenetic markers (intrinsic factors). The expected major advances will be the constitution of a first cartography of the current/fossil trajectories of the porphyrinic compounds and the establishment of a first chronology of appearance of the various porphyrins identified in Vetigastropoda.

Activities

- Implementation of microplate (ELISA type) or membrane (dot-blot type) analytical methods, specially developed to study the chemical affinities between biochromes and the different compounds of the organic phase of the shell (polysaccharides, proteins, etc.) and biochromes.
- Use of new UV-visible and infrared imaging methodologies to characterize the interaction of tetrapyrolic biochromes with the inorganic fraction of the shell matrix within current and fossil gastropods.
- Participation in the commissioning of micro and macro scale luminescence imaging instruments at IPANEMA.
- Participation in the elaboration of beam time proposal on synchrotron for the study of modern and fossil specimens.

Skills

- Ph.D. in materials science, chemistry, or an equivalent field.
- Desired experience in the characterization of organic compounds by spectroscopic and/or separative and/or analytical chemistry methods.
- Tangible experience on the issue of characterization of tetrapyrolic compounds would be a plus.
- Work with heterogeneous solid samples (preparation, handling, microscopy).
- Excellent communication skills.
- Ability to work in a team.
- Autonomy, initiative and adaptability.
- Very good level in spoken and written English.

Work Context

This postdoctoral project will be carried out at the IPANEMA laboratory, which is equipped with all the necessary state-of-the-art tools, as well as at the National Museum of Natural History. The project will also involve two other partners: the research unit BIOGEOSCIENCES and the company PorphyChem (both located on the campus of the University of Burgundy, in Dijon) for the characterization and interpretation of biochromes by chemical separative analyses, trips to Dijon will be organized. IPANEMA is hosted on the site of the SOLEIL synchrotron. The post-doctoral researcher will be required to make frequent use of the state-of-the-art instrumentation within the synchrotron.
The postdoctoral researcher will be part of a multidisciplinary team, which includes PhD students, trainees and young researchers, for whom he may be asked to provide some supervision.
This postdoctoral project will be carried out at IPANEMA (CNRS, MC, UVSQ, MNHN) and at the National Museum of Natural History.
A research and service unit, IPANEMA is the European platform for research on ancient materials (CNRS, Ministry of Culture and Communication, University of Versailles Saint-Quentin-en-Yvelines), located on the site of the SOLEIL synchrotron (Saclay Plateau, south of Paris). IPANEMA is unique in the world in that it is exclusively dedicated to the study of ancient materials (materials from archaeology, paleo-environments, paleontology and cultural heritage) and located on a large instrument. IPANEMA supports scientists who study ancient materials, and develops its own research activities, which focus on advanced imaging and spectroscopic analysis of ancient materials, and statistical data processing. The project ideally takes place at the start of the PUMA line (Photons Used for Ancient Materials), operated by SOLEIL and IPANEMA.

Constraints and risks

Shifted schedules possible punctually within the framework of scientific experiments.

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