Origin and mobility of Iron Age Gaulish groups in present-day France revealed through archaeogenomics.

The Iron Age period occupies an important place in French history because the Gauls are regularly presented as the direct ancestors of the extant French population. We documented here the genomic diversity of Iron Age communities originating from six French regions. The 49 acquired genomes permitted us to highlight an absence of discontinuity between Bronze Age and Iron Age groups in France, lending support to a cultural transition linked to progressive local economic changes rather than to a massive influx of allochthone groups. Genomic analyses revealed strong genetic homogeneity among the regional groups associated with distinct archaeological cultures. This genomic homogenization appears to be linked to individuals' mobility between regions and gene flow with neighbouring groups from England and Spain. Thus, the results globally support a common genomic legacy for the Iron Age population of modern-day France that could be linked to recurrent gene flow between culturally differentiated communities.

Alloyed Pt3M (M = Co, Ni) nanoparticles supported on S- and N-doped carbon nanotubes for the oxygen reduction reaction.

Sulfur- (S-CNT) and nitrogen-doped (N-CNT) carbon nanotubes have been produced by catalytic chemical vapor deposition (c-CVD) and were subject to an annealing treatment. These CNTs were used as supports for small (≈2 nm) Pt3M (M = Co or Ni) alloyed nanoparticles that have a very homogeneous size distribution (in spite of the high metal loading of ≈40 wt % Pt), using an ionic liquid as a stabilizer. The electrochemical surface area, the activity for the oxygen reduction reaction and the amount of H2O2 generated during the oxygen reduction reaction (ORR) have been evaluated in a rotating ring disk electrode experiment. The Pt3M/N-CNT catalysts revealed excellent electrochemical properties compared to a commercial Pt3Co/Vulcan XC-72 catalyst. The nature of the carbon support plays a key role in determining the properties of the metal nanoparticles, on the preparation of the catalytic layer, and on the electrocatalytic performance in the ORR. On N-CNT supports, the specific activity followed the expected order Pt3Co > Pt3Ni, whereas on the annealed N-CNT support, the order was reversed.

Multi-scale ancient DNA analyses confirm the western origin of Michelsberg farmers and document probable practices of human sacrifice.

In Europe, the Middle Neolithic is characterized by an important diversification of cultures. In northeastern France, the appearance of the Michelsberg culture has been correlated with major cultural changes and interpreted as the result of the settlement of new groups originating from the Paris Basin. This cultural transition has been accompanied by the expansion of particular funerary practices involving inhumations within circular pits and individuals in "non-conventional" positions (deposited in the pits without any particular treatment). If the status of such individuals has been highly debated, the sacrifice hypothesis has been retained for the site of Gougenheim (Alsace). At the regional level, the analysis of the Gougenheim mitochondrial gene pool (SNPs and HVR-I sequence analyses) permitted us to highlight a major genetic break associated with the emergence of the Michelsberg in the region. This genetic discontinuity appeared to be linked to new affinities with farmers from the Paris Basin, correlated to a noticeable hunter-gatherer legacy. All of the evidence gathered supports (i) the occidental origin of the Michelsberg groups and (ii) the potential implication of this migration in the progression of the hunter-gatherer legacy from the Paris Basin to Alsace / Western Germany at the beginning of the Late Neolithic. At the local level, we noted some differences in the maternal gene pool of individuals in "conventional" vs. "non-conventional" positions. The relative genetic isolation of these sub-groups nicely echoes both their social distinction and the hypothesis of sacrifices retained for the site. Our investigation demonstrates that a multi-scale aDNA study of ancient communities offers a unique opportunity to disentangle the complex relationships between cultural and biological evolution.

New Method for Super Hydrophobic Treatment of Gas Diffusion Layers for Proton Exchange Membrane Fuel Cells Using Electrochemical Reduction of Diazonium Salts.

The purpose of this article is to report a new method for the surface functionalization of commercially available gas diffusion layers (GDLs) by the electrochemical reduction of diazonium salt containing hydrophobic functional groups. The method results in superhydrophobic GDLs, over a large area, without pore blocking. An X-ray photoelectron spectroscopy study based on core level spectra and chemical mapping has demonstrated the successful grafting route, resulting in a homogeneous distribution of the covalently bonded hydrophobic molecules on the surface of the GDL fibers. The result was corroborated by contact angle measurement, showing similar hydrophobicity between the grafted and PTFE-modified GDLs. The electrochemically modified GDLs were tested in proton exchange membrane fuel cells under automotive, wet, and dry conditions and demonstrated improved performance over traditional GDLs.