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Two novel compounds isolated from an amber sample from the Santonian of Piolenc (Vaucluse, SE France) were identified using nuclear magnetic resonance and high-resolution mass spectrometry as sulfurized analogues of diterpenic acids from the isopimaric series originating from ancient conifers possibly related to the Cupressaceae family. These two compounds are members of a diterpenoid series corresponding to early diagenetic transformation products of resin diterpenoids. They were likely formed once plant resin comes into contact with reduced sulfur species originating from bacterial sulfate reduction occurring in anaerobic settings such as mangroves or marshes. They represent the first evidence of sulfurization processes affecting plant resin prior to diagenetic transformation into amber. Given their mode of formation, these compounds may be used as indicators of sulfate-reducing processes in past depositional environments.

The presence of zinc complexes or of oxidative conditions induces dithiocarbamate transfer from methylene-bis(dithiocarbamates) to molybdenum dithiocarbamates via zinc dithiocarbamate species.

A newly-discovered ligand transfer from methylene-bis(dithiocarbamates) to molybdenum dithiocarbamates (MoDTC) leads to MoDTC regeneration and results in enhanced fuel economy upon engine functioning.

Résumé. Fouillé en 2018 dans le cadre du contournement ouest de Strasbourg, le gisement de Berstett Langenberg (site n° 5.6 du projet) a livré sur près de deux hectares plusieurs occupations successives du Néolithique récent à La Tène finale. L’occupation de l’âge du Bronze se caractérise par 43 structures se répartissant quasiment sur toute l’emprise, tandis que les 31 faits du plein Bronze moyen correspondent à une dizaine de fosses, des silos (sept) et des fonds de silos probables (quatre), deux possibles bâtiments excavés, trois fentes et cinq chablis. Aucun plan de bâtiment n’a été repéré, mais des espaces vides entourés de fosses ou silos suggèrent l’emplacement de bâtiments, tout comme les restes de torchis (architecture de terre et de bois). La quantité importante de vestiges céramiques mise au jour (160 récipients), tout comme plusieurs datations radiocarbones ont permis de mieux caractériser la typochronologie des ensembles pour le Bronze D et la transition Bronze C-D. Certains fonds de silos ont livré des vases vraisemblablement déposés entiers. Une série d’analyses biogéochimiques sur les parois internes d’une dizaine de vases ont permis d’identifier des graisses animales, tout comme des restes d’huile végétale (Brassicacées) ou de résine (Pinacée) pour des usages divers. Au-delà de la quantité importante de mobilier céramique exhumée, qui en fait un site de référence pour la fin du Bronze moyen, les autres types de mobiliers exhumés (lithique, faune) permettent de mieux caractériser ce type de site d’habitat encore peu connu dans l’est de la France. Abstract. Excavated in 2018 as part of the western bypass of Strasbourg, the Berstett Langenberg site of nearly two hectares (site no. 5.6 of the project) has revealed occupations dating from the Late Neolithic to the Final La Tène period. The Bronze Age occupation is characterised by 43 features spread over almost the entire area, while the 31 Middle Bronze Age features include ten pits, storage pits (11), two possible excavated buildings, three slits and five windfalls. No buildings were found, but areas devoid of features surrounded by pits suggest the location of buildings, as do the remains of cob (earth and wood architecture). The large quantity of ceramic remains uncovered (160 vessels), as well as several radiocarbon dates have made it possible to better characterise the typochronology of the ensembles for the Bronze D and the transition from Bronze D to Bronze D. Biogeochemical analysis of the inner walls of ten vessels has revealed animal fats, as well as traces of vegetable oil (Brassicaceae) or resin (Pinaceae). In addition to the large quantity of pottery, which makes the site a reference point, other objects unearthed (lithics, fauna) provide supplementary information as to the late Middle Bronze Age settlement for which little is known in eastern France.

We investigate the optical properties of silicon-vacancy (SiV) and germanium-vacancy (GeV) color centers in nanodiamonds under hydrostatic pressure up to 180 GPa. The nanodiamonds were synthetized by Si or Ge-doped plasma assisted chemical vapor deposition and, for our experiment, pressurized in a diamond anvil cell. Under hydrostatic pressure we observe blue-shifts of the SiV and GeV zero-phonon lines by 17 THz (70 meV) and 78 THz (320 meV), respectively. These measured pressure induced shifts are in good agreement with ab initio calculations that take into account the lattice compression based on the equation of state of diamond and that are extended to the case of the tin-vacancy (SnV) center. This work provides guidance on the use of group-IV-vacancy centers as quantum sensors under extreme pressures that will exploit their specific optical and spin properties induced by their intrinsic inversion-symmetric structure., 7 pages, 4 figures

International audience; Lynchets correspond to talus slopes that are formed unintentionally at the top of hedgerows by the accumulation of colluvial deposits originating from eroded fields. They may represent highly extended parcellar surfaces, characterized by narrow plots, extending perpendicularly to the slope. The history of these plots and their dating are still largely unknown. Our results deal with a land patch of several hundreds of hectares located at Goldbach-Altenbach, in the Vosges (Haut- Rhin). It could be determined on two cross-sections cutting the lynchets transversally that the parcellar plot was formed ca. 900 AD, after which the place was briefly abandoned during the Thirty Years War. The dating at ca. 900 AD suggests that this parcellar area was installed under the authority of the Murbach Abbey. The whole sector was indeed donated to the Abbey ca. 800 AD. Les rideaux de culture sont des talus qui se forment involontairement à l’amont d’une haie, par accumulation de colluvions érodées dans les champs. Ils peuvent constituer des parcellaires de très grande extension spatiale, caractérisés par des parcelles étroites, allongées perpendiculairement à la pente. L’histoire de ces parcellaires et leur datation sont encore très mal connues. Les résultats présentés ici concernent un parcellaire de plusieurs centaines d’hectares localisé à Goldbach-Altenbach, dans les Vosges haut-rhinoises. Les résultats obtenus sur deux coupes transversales à des rideaux de culture montrent que le parcellaire a été mis en place vers 900 AD, puis que la zone a été brièvement abandonnée pendant la Guerre de Trente Ans. La datation vers 900 AD suggère que ce parcellaire a été mis en place sous l’autorité de l’abbaye de Murbach. L’ensemble de la zone a en effet été donné à cette abbaye vers 800 AD.

Molybdenum dithiocarbamates (MoDTC) are widely used in automotive industries as lubricant additives to reduce friction and to enhance fuel economy. Sulfur-containing additives such as zinc dithiophosphates (ZnDTP) are proposed to play a key role in the improvement of friction reducing properties of MoDTC in formulated lubricants by facilitating the formation of MoS2 tribofilm at the rubbing contacts. This study focuses on the interactions between MoDTC and ZnDTP under conditions comparable with those prevailing in operating engines. The capacity of ZnDTP to sulfurize MoDTC in solution in a hydrocarbon base oil could be demonstrated. Sulfurized Mo complexes bearing one or two additional sulfur atoms (1S-MoDTC and 2S-MoDTC, respectively) which have replaced the genuine oxygen atom(s) from the MoDTC core were detected and quantified using a specifically developed HPLC-MS analytical method. A possible sulfurization mechanism relying on the higher affinity of phosphorus from ZnDTP for oxygen could be proposed. In parallel, the evolution and molecular transformation of the prepared 2S-MoDTC in hydrocarbon base oil under thermal and thermo-oxidative conditions were followed using HPLC-MS and compared with the evolution of their friction coefficients. 2S-MoDTC complexes were shown to exhibit a better retention of friction reducing capability under oxidative conditions than the "classical" MoDTC, although they did not seem to significantly reduce the friction coefficients of lubricants as compared to the "classical" MoDTC. Therefore, sulfurization of MoDTC by ZnDTP might contribute to delay the progressive consumption of MoDTC and the loss of their friction-reducing efficiency in lubricants under thermo-oxidative conditions.

https://hal.archives-ouvertes.fr/hal-03252301; International audience

International audience; A harmonic oscillator model is proposed to study the intensification of microwave radiation of an electrically small antenna when surrounded by a subwavelength plasma discharge. This model describes the oscillations of free electrons in a spherical plasma when it is excited by an incident electromagnetic wave. It shows that at resonance, these charge oscillations lead to a significant volume current, and thus to an enhancement of the radiation. Depending on the electron density of the plasma, this radiation enhancement may occur in the microwave range. The proposed model is compared with the Mie scattering theory with perfect agreement when the electrical size ka of the spherical plasma remains smaller than 0.1. Despite its apparent simplicity, this model unveils the main mechanism that stands behind the intensification of microwave radiation by a subwavelength plasma discharge.

The absence of unambiguous animal body fossils in rocks older than the late Ediacaran has rendered fossil lipids the most promising tracers of early organismic complexity. Yet much debate surrounds the various potential biological sources of putative metazoan steroids found in Precambrian rocks. Here we show that 26-methylated steranes—hydrocarbon structures currently attributed to the earliest animals—can form via geological alteration of common algal sterols, which carries important implications for palaeo-ecological interpretations and inhibits the use of such unconventional ‘sponge’ steranes for reconstructing early animal evolution. Via congruent observations in geological samples and pyrolysis experiments, the authors demonstrate that 26-alkylsteranes posited as sponge biomarkers can form during diagenesis of common algal sterols.

International audience; The tribological performances of engine oils have been shown to be enhanced by the synergistic interactions between Mo dithiocarbamates (Mo(DTC)2) with other additives, and notably Zn dithiophosphates (Zn(DTP)2). Being two key components in formulated lubricants, a detailed understanding of the mechanisms involved between these two types of additives is needed to develop engine oils with enhanced friction reduction performances, and improved fuel economy. In this context, we report here the investigation at the molecular level of the interactions between Mo and Zn complexes with DTC and DTP ligands using laboratory experiments. Our analytical approach comprised NMR spectroscopy (1H, 13C, 31P) allowing direct investigation of both homoleptic and heteroleptic Mo and Zn complexes as well as a specifically-developed HPLC-MS method for the investigation of the different DTC species formed during lubricant ageing experiments. The results showed that ligand exchange reactions between Mo(DTP)2 and Zn(DTC)2 complexes strongly favor the migration of the DTC ligands from Zn to Mo, illustrating the higher affinity of Mo for DTC ligands. In the case of binary mixtures involving Mo(DTC)2 and Zn(DTP)2 – a combination of additives frequently used in formulated lubricants – the formation of mixed complexes (Mo(DTC)(DTP)) resulting from ligand exchange reactions could be directly evidenced for the first time by the analytical methods used. These species could account, at least to some extent, for the synergistic effect of Mo(DTC)2 and Zn(DTP)2 on the friction reducing properties of engine oils. However, they were formed in significantly lower proportions than those previously reported in the literature using indirect methods

The tribological performances of engine oils have been shown to be enhanced by the synergistic interactions between Mo dithiocarbamates (Mo(DTC)

International audience; The biomarker distributions of mid-Neoproterozoic sediments (800–717 million yr, Ma) from various locations are characterized by the occurrence, besides cholestane isomers, of a novel series of C28 steranes, whereas classical C-24 alkylated steranes are absent. These unusual C28 steranes, termed cryostanes, seem to be restricted to pre-Snowball Earth sediments. We report their conclusive identification as 26-methyl cholestanes based on comparison of gas chromatographic (GC) behavior and mass spectrum of the last eluting cryostane isomer with those of a 26-methyl 5α(H),14α(H),17α(H),20R-cholestane standard obtained by way of synthesis. Sterols methylated at C-26 seem to be restricted to some demosponges and, based on molecular clock estimates, demosponges may have emerged in the time interval 800–700 Ma. A sponge origin of cryostanes is thereby conceivable, making cryostanes the oldest molecular markers for animals. However, other biological sources need to be explored, including the wide variety of eukaryotic protists.

A preliminary study of the design of an electrically small plasma-based resonator using a localized surface plasmon resonance (LSPR) above 1 GHz is presented. Such a resonator is intended to be used to develop an electrically small antenna with frequency agility. This resonator consists of a plasma discharge confined in a hemispherical glass shell 3 cm in diameter on a ground plane. From 1 to 1.5 GHz, the plasma electron density required to achieve the LSPR must be between 0. $5\times 10^{11}$ and $1.4\times 10^{11}\mathrm{c}\mathrm{m}^{-3}$. Plasma losses are taken into account in this study and provide information on the required gas pressure. Typically for neon gas, the working pressure must be around 50 mTorr. A practical implementation using a miniature inductively coupled plasma (mICP) source is finally discussed.

Birch bark tar, an organic material frequently encountered during archaeological excavations, has been identified from its lipid composition on the cracks of a ceramic dated to the late Neolithic. Lipids of this black substance were dominated by a characteristic triterpenoid assemblage of lupane-related triterpenoids from birch bark, together with their thermal degradation products formed during preparation of the tar. Among the latter, four main series of unusual triterpenoid esters have been detected and were postulated to correspond to esters of Δ 2-betulin and Δ2-dihydrobetulin based on their mass spectra and hydrolysis experiments. Their conclusive identification has been achieved by synthesis of reference compounds. These compounds most likely originate from the esterification between triterpenoid alcohols related to betulin and fatty acids from suberin formed upon heating of birch bark tar. They could be considered as markers of intense heating during birch bark tar preparation using the “single pot” procedure.

The widely distributed aromatic di- and triterpenoids from higher plants occurring in sediments are formed by diagenetic microbial processes affecting their precursor plant lipids. These compounds and their stable isotopic composition (δ13C and δ2H) have the potential to be used for palaeoenvironmental and palaeoclimatic studies. In the present study, the isotopic composition of di- and triterpenoids aromatized to different extents has been measured to specifically examine the isotopic effects associated with the aromatization reaction. To overcome the possibility of multiple higher plant sources, as is generally the case with sedimentary lipids, the δ13C and δ2H values of aromatized di- and triterpenoids from lipid extracts recovered from conifer and angiosperm buried wood have been determined, allowing an unambiguous substrate/product relationship along the aromatization pathway to be assured. The results show that the δ13C compositions of both di- and triterpenes do not seem to be significantly affected by progressive aromatization, whereas the situation is different for δ2H values. In the case of diterpenoids related to abietic acid, a significant increase of the δ2H values by up to 86‰ with ongoing aromatization was measured. This is in contrast to what is expected for dehydrogenated compounds which should be globally more 2H-depleted than their precursor molecules (e.g., biosynthesized unsaturated fatty acids vs. their saturated precursors). This 2H enrichment of aromatized diterpenoids could indicate that they represent only minor residual intermediates, the majority having been further degraded by processes favoring the degradation of the 1H-containing substrates and having a moderately pronounced 12C/13C selectivity. With triterpenoids, preservation of the δ2H values was observed whatever the nature and extent of the aromatization process considered, which may be related to enzymatic reactions showing a limited influence on the hydrogen stable isotopic composition of the aromatized compounds.

International audience; Plant exudates have been extensively used in the past for different applications related to their olfactory, physical or medical properties. Their identification in archaeological samples relies, notably, on the characterisation of chemotaxonomic molecular markers but is often hampered by the severe alteration of their typical genuine molecular signature due to ageing. Among these exudates, those recovered from Styrax, Liquidambar and Myroxylon tree species – defined as balsams – have been exploited in the past for their pleasant scent and medical properties. They are characterised by a large variety of aromatic compounds, especially of the cinnamate and benzoate series, which can be used to assess their botanical source. These compound series may, however, be subject to alteration over time during exposure to environmental conditions in the case of archaeological material. As a result, their reliability as chemotaxonomic markers to characterise and discriminate archaeological balsams is problematic and questionable. We have, therefore, carried out a comparative analysis of various extant balsams (Styrax officinalis, S. paralleloneurum, S. tonkinensis, Liquidambar styraciflua, L. orientalis and Myroxylon balsamum var. pereirae) using gas chromatography–mass spectrometry to search for more solid lipid markers. The results revealed that a distinction between styrax, liquidambars, Peru and Tolu balsams is possible based on the distribution of pentacyclic triterpenes. The predominance of uncommon 6‑oxygenated derivatives of oleanolic acid among triterpenoids could be specifically related to styrax resins. Liquidambar gums were characterised by the predominance of oleanonic acid together with uncommon 3-epi oleanolic and ursolic acids, whereas Peru balsam was rich in cinnamic and benzoic acids, but devoid of triterpenoids. Thanks to the high specificity of some of these triterpenes, already known for their low volatility and robustness towards alteration processes, they should be considered as reliable molecular tools for the unambiguous identification of archaeological balsams. In addition to archaeological applications, these triterpenic markers might also find an application for the detection of counterfeit balsams.

The design of a quad-band (18, 28, 38, and 48 GHz) feed horn is presented. Corrugations are used for a good polarization purity at the higher frequencies. At the lower frequency, they act as a smooth wall and the horn profile is tuned to achieve a high aperture efficiency.

International audience; Deciphering the role of sulfur in biogeochemical cycles strongly relies on its stable isotope composition, which ultimately depends on the ability to quantitatively recover different sulfur species from geological samples. For decades most studies have been restricted to the 34S/32S composition of bulk samples, using simple methods based on the analysis of SO2 released by sample combustion combined to mass spectrometry. The wet chemistry procedures required to selectively extract specific sulfur species were generally avoided due to their tediousness and inefficiency for some complex matrices, especially when targeting organic sulfur. With the recent advent of multi-isotope studies (investigating the minor sulfur stable isotopes 33S and 36S) which rely either on the analysis of sulfur as SF6, or on the use of secondary ion or multi-collector inductively coupled plasma mass spectrometry, wet chemistry-based preparation procedures were brought back to the stage with a renewed interest in developing procedures better adapted to the investigation of specific sulfur species. Here we propose a new stepwise chemical procedure for the quantitative recovery and multi-isotope analysis of organic sulfur from both solvent soluble (total lipid extract) and insoluble (kerogen) fractions, based on a wet oxidation by sodium hypochlorite. This procedure also allows the multi-isotope analysis of inorganic sulfur species (elemental sulfur, sulfates and sulfides) in the same sample. Its application to different well-known petroleum source rocks and to an oil demonstrates its relevance for disentangling the interactions between the different sulfur pools and for shedding new light on the sulfur biogeochemical cycle.

International audience

Sulfur is a key element of biogeochemical cycles, being both an essential component of living cells and involved in major geological processes. Its four stable isotopes (32S, 34S, 33S, 36S, in order of abundance) are subject to equilibrium and kinetic fractionations, which can be used as tracers to understand sulfur cycling processes. Multi-isotope studies noticeably revealed mass-independent fractionation processes of 33S and 36S, enlightening previously unknown specific organic or inorganic (bio)(geo)chemical mechanisms. Though the analytical procedures for the determination of S-multi-isotope compositions, which requires a quantitative extraction and purification of sulfur, are well-known for mineral sulfur species, the existing procedures for the extraction of organic sulfur are either restricted to specific species or technically restrictive. Here we propose a new chemical procedure for the quantitative recovery of organic sulfur in the form of Ag2S, for multi-isotope analysis, which is also compatible with the multi-isotope analysis of inorganic sulfur species from the same samples. This procedure is based on a standard sequence of reductive attacks specific of mineral sulfur species and was validated on various samples including fresh sediments, source rocks and oils.

International audience; Organic residue analysis has been undertaken on an organic material found on a necklace with a pendant unearthed from a necropolis dated to the Early Iron Age (800-475 BC) and located in Eckwersheim (NE France). The molecular composition of the substance, which was investigated using gas chromatography coupled to mass spectrometry, points towards an adhesive used to stick two bronze half-spheres to form a pendant. The predominance of triterpenoids from the lupane series led to the identification of the adhesive as a birch bark tar and constitutes a rare example of the use of such a material in jewellery in the past

International audience; Brain diseases such as autism and Alzheimer's disease (each inflicting >1% of the world population) involve a large network of genes displaying subtle changes in their expression. Abnormalities in intraneuronal transport have been linked to genetic risk factors found in patients, suggesting the relevance of measuring this key biological process. However, current techniques are not sensitive enough to detect minor abnormalities. Here we report a sensitive method to measure the changes in intraneuronal transport induced by brain-disease-related genetic risk factors using fluorescent nanodiamonds (FNDs). We show that the high brightness, photostability and absence of cytotoxicity allow FNDs to be tracked inside the branches of dissociated neurons with a spatial resolution of 12 nm and a temporal resolution of 50 ms. As proof of principle, we applied the FND tracking assay on two transgenic mouse lines that mimic the slight changes in protein concentration (∼30%) found in the brains of patients. In both cases, we show that the FND assay is sufficiently sensitive to detect these changes.

Euphorbia species are characterized by a net of laticifers producing large amounts of triterpenes. These hydrocarbon-like metabolites can be converted into fuel by the methods of the oil industry. Euphorbia lathyris is easily grown at an industrial scale. In an attempt to increase its triterpene production, the metabolic pathways leading to isoprenoid were investigated by incorporation of 13C labeled glucose and mevalonate and 2H labeled deoxyxylulose as well as by natural abundance isotope ratio GC-MS. Latex triterpenes are exclusively synthesized via the mevalonate (MVA) pathway: this may orient future search for improving the triterpene production in E. lathyris. Phytosterols and their precursors are mainly derived from MVA pathway with a slight contribution of the methylerythritol phosphate (MEP) pathway, whereas phytol is issued from MEP pathway with a minor contribution of the MVA pathway: this is in accordance with the metabolic cross-talk between cytosolic and plastidial compartments in plants. In addition, hopenol B behaved differently from the other latex triterpenes. Its 13C isotope abundance after incorporation of 13C labeled glucose and its natural abundance &delta, 2H signature clearly differed from those of the other latex triterpenes indicating another metabolic origin and suggesting that it may be synthesized by an endophytic fungus.

Two commonly used proxies based on the distribution of glycerol dialkyl glycerol tetraethers (GDGTs) are the TEX86 (TetraEther indeX of 86 carbon atoms) paleothermometer for sea surface temperature reconstructions and the BIT (Branched Isoprenoid Tetraether) index for reconstructing soil organic matter input to the ocean. An initial round-robin study of two sediment extracts, in which 15 laboratories participated, showed relatively consistent TEX86 values (reproducibility +/- 3-4 degrees C when translated to temperature) but a large spread in BIT measurements (reproducibility +/- 0.41 on a scale of 0-1). Here we report results of a second round-robin study with 35 laboratories in which three sediments, one sediment extract, and two mixtures of pure, isolated GDGTs were analyzed. The results for TEX86 and BIT index showed improvement compared to the previous round-robin study. The reproducibility, indicating interlaboratory variation, of TEX86 values ranged from 1.3 to 3.0 degrees C when translated to temperature. These results are similar to those of other temperature proxies used in paleoceanography. Comparison of the results obtained from one of the three sediments showed that TEX86 and BIT indices are not significantly affected by interlaboratory differences in sediment extraction techniques. BIT values of the sediments and extracts were at the extremes of the index with values close to 0 or 1, and showed good reproducibility (ranging from 0.013 to 0.042). However, the measured BIT values for the two GDGT mixtures, with known molar ratios of crenarchaeol and branched GDGTs, had intermediate BIT values and showed poor reproducibility and a large overestimation of the true (i.e., molar-based) BIT index. The latter is likely due to, among other factors, the higher mass spectrometric response of branched GDGTs compared to crenarchaeol, which also varies among mass spectrometers. Correction for this different mass spectrometric response showed a considerable improvement in the reproducibility of BIT index measurements among laboratories, as well as a substantially improved estimation of molar-based BIT values. This suggests that standard mixtures should be used in order to obtain consistent, and molar-based, BIT values.

International audience; Nitrogen-vacancy (NV) color centers in nanodiamonds are highly promising for bioimaging and sensing. However, resolving individual NV centers within nanodiamond particles and the controlled addressing and readout of their spin state has remained a major challenge. Spatially stochastic super-resolution techniques cannot provide this capability in principle, whereas coordinate-controlled super-resolution imaging methods, like stimulated emission depletion (STED) microscopy, have been predicted to fail in nanodiamonds. Here we show that, contrary to these predictions, STED can resolve single NV centers in 40–250 nm sized nanodiamonds with a resolution of ≈10 nm. Even multiple adjacent NVs located in single nanodiamonds can be imaged individually down to relative distances of ≈15 nm. Far-field optical super-resolution of NVs inside nanodiamonds is highly relevant for bioimaging applications of these fluorescent nanolabels. The targeted addressing and readout of individual NV– spins inside nanodiamonds by STED should also be of high significance for quantum sensing and information applications.

Molecular and isotopic investigation of lipids from soils filling several structures from an archaeological site located at Obernai (Alsace, NE France) has revealed the presence of miliacin, a triterpenoid marker from Panicum miliaceum (broomcorn millet), indicating that this cereal was cultivated at the site. The concentration profiles of miliacin within silos and its detection in other archaeological structures (e.g., Gaulish pit) suggest that miliacin did not originate from cereals stored in the silos but rather came from remains of millet from cultivated soils which filled the silos after they were abandoned. Furthermore, the 14C age of miliacin isolated from a silo of the Second Iron Age was shown to be considerably older (Bronze Age) than the structure itself, revealing that the soil filling the silo therefore archived the molecular signature from past millet cropping, predating the digging of the silo. Thus, radiocarbon dating of the isolated miliacin allowed the timing of millet cropping to be determined, showing that it was established during the Bronze Age and the Roman Gaul period at Obernai. This is the first evidence of millet cultivation in Alsace dating back to the Bronze Age, bringing new perspectives on agricultural practices and past dietary practice in Eastern France. The combination of molecular studies and radiocarbon dating of individual lipids highlights the potential of hollow structures like silos and pits to act as “pedological traps”, recording information on past vegetation cover or agricultural practices from the surface horizons of surrounding soils that filled these structures after abandonment.

International audience; Organic substances from three jars found at Abydos in the tombs of Kings from the two first Egyptian dynasties (3100–2700 BCE) were investigated using gas chromatography–mass spectrometry in order to assess their biological origin, use and mode of preparation. The organic material was found to correspond to essential oils from conifers severely altered/oxidized. A predominant contribution from Cedrus libani was determined from the identification of sesquiterpenoid derivatives of the himachalene series which constitute new molecular tools for the identification of ancient oils made from real cedars. The presence of cuparene-related terpenoids suggests an additional contribution of members from the Cupressaceae family (junipers, cypresses). The genuine substances were most likely prepared in the Levant since neither C. libani nor junipers or cypresses are native from Egypt. Despite obvious analogies with “cedrium” used for embalming during later periods, their use as ingredients for embalming remains uncertain because true embalming only began in Egypt after 2500 BCE. Instead, it is proposed that these substances have been used as cosmetics, medicinal substances or for cultual purposes. The predominance of low molecular weight sesquiterpenoids and the absence of typical markers for wood tars indicate that the substances have possibly been prepared by steam-distillation of odoriferous plant material rather than by pyrolysis. Our study gives clues to the controversy concerning the composition of “cedrium”, indicating that it most likely originates from mixed true cedar and junipers or cypresses, and not exclusively from real cedar vs. juniper oil.

International audience; Resinous material from conifers from the Pinaceae family is frequently found in an archaeological context. The material was used, notably, as waterproofing agent, as adhesive or for the caulking of boats. Two main types of material can be distinguished: resin, the exudate of conifer trees, and wood tar obtained by dry distillation of wood. Molecular investigation of such material aims, notably, at developing new molecular tools for the determination of the biological and geographical origin or of the manufacturing techniques, and for the discrimination between resin and wood tar. In this context, we report the identification by synthesis of alkyl guaiacyl dehydroabietates, which occur in a series of recent and archaeological conifer wood tar samples from shipwrecks and Gallo-Roman tar preparation sites. They most likely result from the reaction of dehydroabietic acid and alkyl guaiacols, the latter being typical wood pyrolysis products formed during the preparation of wood tar. Alkyl guaiacyl dehydroabietates are therefore proposed to be specific molecular markers for conifer wood tar, allowing a clear molecular distinction between this material and resin to be made. They are also more resistant to the alteration undergone by archaeological samples than other compounds previously proposed as markers of conifer wood tar such as anhydrosugars or alkyl guaiacols.

Mortuary practices in human evolution record cognitive, social changes and technological innovations. The Neolithic Revolution in the Levant was a watershed in this domain that has long fascinated the archaeological community. Plaster modelled skulls are well known at Jericho and several other Neolithic sites, and in Nahal Hemar cave (Israel, ca. 8200 −7300 cal. BC) excavations yielded six unique human skulls covered with a black organic coating applied in a net pattern evoking a headdress. This small cave was used as storage for paraphernalia in the semi-arid area of the Judean desert and the dry conditions preserved other artefacts such as baskets coated with a similar dark substance. While previous analysis had revealed the presence of amino acids consistent with a collagen signature, in the present report, specific biomarkers were characterised using combined proteomic and lipid approaches. Basket samples yielded collagen and blood proteins of bovine origin (Bos genus) and a large sequence coverage of a plant protein charybdin (Charybdis genus). The skull residue samples were dominated by benzoate and cinnamate derivatives and triterpenes consistent with a styrax-type resin (Styrax officinalis), thus providing the earliest known evidence of an odoriferous plant resin used in combination with an animal product.

This article deals with the impact of ionospheric electron density inhomogeneities on the functionality of global navigation satellite systems emphasizing positioning errors. The scintillation characteristics of transmitted signals have been obtained using data gathered in measurement campaigns. The effects on a standard receiver are then presented. Positioning errors due to scintillations were shown to be greater than 10 meters in the worst case.

International audience; Improving workgroup assessment is a constant concern for teachers involved in complex project courses. Mixing classical teacher's assessment with more innovative peer assessment has definitely given a richer and more accurate insight of the group dynamics. Nevertheless, it has side effects that need to be managed. A performance measurement system strongly influences the way students work. So the group dynamics are largely dependent on the way students feel evaluated. As a consequence, introducing peer assessment gives more autonomy to students group on one hand but also gives them a powerful tool to influence directly their own organisation and dynamics. It is also an individual tool to favour introspective evaluation regarding personal involvement. We aim to educate future managers who will have to motivate teams, reward merit, fairly penalise and negotiate objectives and trade-offs. Even if students agree on peer assessment and score distribution, this agreement does not give the solution by itself. The methodology and ethics of the score distribution seem more important than the result itself. Guaranteeing fairness in score distribution cannot be done without external intervention - i.e. a teacher-. Over four years, the full assessment mechanism has been improved but has also highlighted this fact. The trade-off between careful but sometimes intrusive teacher monitoring on one side and student autonomy on the other side is still to be looked for.

In this paper, a review is presented on computational methods for the prediction of Radar Cross-Sections (RCS) and antenna–platform interactions. In a first part the techniques for RCS computations are considered. A list of frequency and time domain solvers for the Maxwell's equations are given with their performances in memory requirements and run-time. Boundary Elements Methods, Finite Difference Time Domain Methods, Finite Elements—Finite Volume Methods, Hybridization and Factorization Techniques, are reviewed. The exceptional performances of the Fast Multipole Method compared to those of the classical Moment Method are especially highlighted. We have also made mention of some recent research work on numerical techniques conducted in France. Asymptotic methods are mainly discussed in the second part of this article devoted to antenna–platform interactions. After a brief description of the historical evolution of Geometrical Theory of Diffraction tools for antenna analysis and design, the advantages and drawbacks of different techniques for generating the geometry and searching the rays are discussed. Then a list of unsolved problems and lines of future research on asymptotic techniques are presented together with an example of a computer code founded on the Uniform Theory of Diffraction. In the conclusion some new research topics such as higher order finite elements defined on surfaces represented by B-Splines and macro-basis functions containing information on the phase or derived from analytical or asymptotic solutions are briefly introduced. To cite this article: F. Molinet et al., C. R. Physique 6 (2005).

Although perfectly transparent specimens are imaged faster with light-sheet microscopy, less transparent samples are often imaged with two-photon microscopy leveraging its robustness to scattering; however, at the price of increased acquisition times. Clearing methods that are capable of rendering strongly scattering samples such as brain tissue perfectly transparent specimens are often complex, costly, and time intensive, even though for many applications a slightly lower level of tissue transparency is sufficient and easily achieved with simpler and faster methods. Here, we present a microscope type that has been geared toward the imaging of semicleared tissue by combining multispot two-photon excitation with rolling shutter wide-field detection to image deep and fast inside semicleared mouse brain. We present a theoretical and experimental evaluation of the point spread function and contrast as a function of shutter size. Finally, we demonstrate microscope performance in fixed brain slices by imaging dendritic spines up to 400-μm deep.

Previous studies (Ertlen et al., 2010) have shown that near infrared (NIR) spectroscopy of soil organic matter (SOM) can be used successfully to discriminate between SOM from topsoils under forest vs. grassland following establishment of a referential. We have now extended this referential of topsoils, and the derived model was used to characterize SOM within three soil profiles in order to test if vegetation changes throughout these profiles can be detected using NIR spectra from buried soil organic matter. Comparison between the results from this new proxy based on NIR measurements and other historical and pedoanthracological data documenting soil occupation shows no major contradiction in terms of vegetation cover and its evolution with time. These promising results will need further development in order to provide a new palaeoenvironmental tool that is far less time consuming and easier to handle than other methods like pedoanthracology or soil lipid analysis.

We report here the development of an analytical protocol for the specific isolation of isoprenoid and branched glycerol dialkyl glycerol tetraethers (i-and br-GDGTs, respectively) of microbial origin from soil samples for radiocarbon dating. This protocol comprises an extraction step followed by several chromatographic steps combining different techniques (silica gel column chromatography, high performance liquid chromatography and thin layer chromatography). Radiocarbon dating of these two series of compounds, isolated from a surface sample and a deep horizon sample (40-50 cm) from a soil profile, shows that i-and br-GDGTs in the deep sample have a comparable mean residence time (MRT), despite their different biological origin. These MRT are, however, lower than those measured for the soil organic matter (SOM) and for the different compartments of SOM. This result suggests that i-and br-GDGTs originate from microorganisms using the same carbon source, made of a combination of ancient and recent organic matter. It can also be envisaged that these compounds originate from both recent and ancient microbial populations. These preliminary results suggest that the use of (palaeo) proxies based on the distributions of GDGTs might be questionable in the case of soils or, at least, that caution is needed when interpreting soil GDGT signals in terms of (palaeo) environmental reconstructions., Nous rapportons dans cette étude le développement d’un protocole analytique pour l’isolement spécifique, à partir d’échantillons de sol, des tétraéthers de diglycérol isoprénoïdes (i-GDGT) et ramifiés (br-GDGT), composés d’origine microbienne, dans le but de procéder à leur datation au 14C. Ce protocole comprend une étape d’extraction de la composante lipidique du sol avec des solvants organiques, suivie d’étapes de séparation et de purification par différentes techniques chromatographiques (chromatographie liquide sur colonne, chromatographie liquide à haute performance et chromatographie sur couche mince). Après isolement, la datation au 14C de ces deux séries de composés dans deux échantillons d’un profil de sol, l’un de surface, l’autre en profondeur (40-50 cm) indique qu’en dépit d’une origine biologique distincte, les i-et br-GDGT présentent des temps moyens de résidence (TMR) similaires en profondeur, TMR qui sont inférieurs à ceux de la matière organique de ce même échantillon et des différents compartiments qui la constituent. Ceci suggère soit que ces lipides proviennent de microorganismes utilisant une même source de carbone constituée d’un mélange d’une matière organique récente et ancienne, à moins qu’ils ne proviennent d’un mélange provenant d’une population ancienne et d’une population plus récente. Quoi qu’il en soit, ces observations préliminaires suggèrent que l’utilisation de (paléo) proxies reposant sur la distribution des GDGT dans le cas des sols est parfois discutable, ou, tout au moins, incitent à la prudence quant à d’éventuelles interprétations dans le cadre de reconstitutions (paléo) environnementales., Courel Blandine, Schaeffer Philippe, Adam Pierre, Ertlen Damien, Schwartz Dominique, Bernasconi Stefano, Hajdas Irka. Analyse, isolement et datation au 14C de lipides dans les sols : l’exemple des tétraéthers de diglycérol. In: Collection EDYTEM. Cahiers de géographie, numéro 18, 2015. Sols et matières organiques. Mémoires et héritages. pp. 57-68.

High pressure high temperature (HPHT) nanodiamonds (NDs) represent extremely promising materials for construction of fluorescent nanoprobes and nanosensors. However, some properties of bare NDs limit their direct use in these applications: they precipitate in biological solutions, only a limited set of bio-orthogonal conjugation techniques is available and the accessible material is greatly polydisperse in shape. In this work, we encapsulate bright 30-nm fluorescent nanodiamonds (FNDs) in 1020-nm thick translucent (i.e., not altering FND fluorescence) silica shells, yielding monodisperse near-spherical particles of mean diameter 66 nm. High yield modification of the shells with PEG chains stabilizes the particles in ionic solutions, making them applicable in biological environments. We further modify the opposite ends of PEG chains with fluorescent dyes or vectoring peptide using click chemistry. High conversion of this bio-orthogonal coupling yielded circa 2000 dye or peptide molecules on a single FND. We demonstrate the superior properties of these particles by in vitro interaction with human prostate cancer cells: while bare nanodiamonds strongly aggregate in the buffer and adsorb onto the cell membrane, the shell encapsulated NDs do not adsorb nonspecifically and they penetrate inside the cells.

Das Schloss von Bois-Sire-Amé, von Jean-Pierre Adam, Nicolas Faucherre, Jean Mesqui und Armelle Querrien Die Bedeutung der ausgezackten Ruine des Schlosses von Bois-Sire-Amé im Süden der Stadt Bourges liegt besonders in seiner Baugeschichte : Ohne dass es topographisch zwingend war, wurde eine Burganlage von einem Waldrand an einen anderen verpflanzt, wobei sukzessive zwei verschiedene Baukonzeptionen verwirklicht wurden : zunächst eine Grenzfestung in einer unruhigen Region und dann eine zurückgezogene «folly » , also ein extravagantes Lustschloss, zunächst eine Erdhügelburg mit zwei äußeren Höfen und dann ein Landpalais für urbane Emporkömmlinge. Das Gebäude wurde ex nihilo errichtet und zwar nicht, wie bisher allgemein angenommen um 1440, als Liebesnest für Agnès Sorel und Karl VII., sondern Jacquelin V. Trousseau, Haushofmeister von Jean de Berry ließ es in stilistisch starker Nähe zu den großen Bauprojekten der Herzöge von Bourges und Mehun an derWende zum 15. Jhd. errichten. Somit legt das Schloss von Bois-Sire-Amé ein außergewöhnliches Zeugnis ab von den Ambitionen eines Offiziers am herzoglichen Hof und dessen junger dynastischer Basis. Es ist als Huldigung an Philippe de la Charité, seine Gemahlin konzipiert und mit einem Luxus ausgestattet, der den des Erbauers widerspiegelt., The castle of Bois-Sire-Amé, by Jean-Pierre Adam, Nicolas Faucherre, Jean Mesqui, Armelle Querrien The primary interest of Bois-Sire-Amé, a jagged ruin south of Bourges, relates to the exemplary history of the displacement of the castle site to the edge of a wood, without any topographical constraint, and the successive adoption of two castle models : a frontal fortress in an unstable zone changed into a withdrawn folly, a motte with two enclosed courts transformed into a country palace for an urban upstart. Contrary to traditional thought, the castle was built from scratch not around the 1440s as an amorous hideaway for Agnès Sorel and Charles VII, but at the beginning of the 15th century for one of the maîtres d’hôtel of Jean de Berry, Jacquelin V Trousseau. Closely related stylistically to the great ducal constructions at Bourges and Mehun, Bois-Sire-Amé is an extraordinary testimony to the ambitions of an officer of the ducal court and his new family position ; it was conceived as an homage to his wife, Philippe de la Charité, and carried out with a luxury worthy of his master., Le premier intérêt de Bois-Sire-Amé, ruine déchiquetée du sud de Bourges, tient à l’histoire exemplaire d’un déplacement de site castral à l’orée d’un même bois, sans contrainte topographique, avec l’adoption de deux modèles castraux successifs, de la forteresse frontalière en zone d’instabilité à la «folie » retirée, de la motte à deux basses-cours au palais des champs pour un parvenu urbain. Bâti ex nihilo, non pas vers 1440 pour abriter les amours d’Agnès Sorel et de Charles VII, comme le veut la tradition, mais au tournant des années 1400 par l’un des maîtres d’hôtel de Jean de Berry, Jacquelin V Trousseau, en grande proximité stylistique avec les grands chantiers ducaux de Bourges et de Mehun, Bois-Sire-Amé constitue un extraordinaire témoignage sur l’ambition d’un officier de la cour ducale et sur sa nouvelle assise familiale ; il est conçu comme un hommage à son épouse, Philippe de la Charité, et réalisé avec un luxe qui reflète celui de son maître., Adam Jean-Pierre, Faucherre Nicolas, Mesqui Jean, Querrien Armelle. Le château de Bois-Sire-Amé. In: Bulletin Monumental, tome 170, n°2, année 2012. pp. 99-138.

International audience; The ability of diamond nanoparticles (nanodiamonds, NDs) to deliver small interfering RNA (siRNA) into Ewing sarcoma cells is investigated with a view to the possibility of in-vivo anticancer nucleic-acid drug delivery. siRNA is adsorbed onto NDs that are coated with cationic polymer. Cell uptake of NDs is demonstrated by taking advantage of the NDs' intrinsic fluorescence from embedded color-center defects. Cell toxicity of these coated NDs is shown to be low. Consistent with the internalization efficacy, a specific inhibition of EWS/Fli-1 gene expression is shown at the mRNA and protein level by the ND-vectorized siRNA in a serum-containing medium.

[1] This paper presents the results of a scintillation measurement campaign. The receivers used during this campaign were located in five regions of the globe which allowed us to investigate geographic similarities and differences. Most of the receivers were located in the equatorial region, and one of them was located at high latitudes. Significant results were achieved even though the measurement period was around solar minimum. An intercomparison with the Wide-Band Scintillation Model and the Global Ionosphere Scintillation Model has been carried out, and the construction of scintillations maps has been initiated.

International audience; Techniques to reduce LCD motion blur are extensively used in industry and they depend on an inherent LCD parameter: response time. However, normative response time is not a sufficient reference to improve LCD performance and all the gray-to-gray response-time quantities are required to obtain good improvement. However, measuring and gathering all the gray-to-gray transitions takes an excessive amount of time. Consequently, we propose a novel LCD model to simulate as well as compute gray-to-gray transitions (response time and behavior) from a reduced measurement set in order to decrease the response-time measurement.

Adam Jean-Pierre. La défense des portes dans le monde grec. In: Bulletin Monumental, tome 151, n°1, année 1993. pp. 9-17.

Decouvert en 1902, le castellum aquae de Pompei fut construit au point le plus haut de la cite, appuye au flanc Ouest de la porte du Vesuve. Dans le bassin de l’edifice etaient recueillies les eaux provenant d’une branche de l’aqueduc de Serino realise durant l’epoque augusteenne, comme du reste le fut le castellum de Pompei. Avant de partir dans les canalisations urbaines, l’eau, a la sortie du specus, devait traverser la grille de fermeture entre la galerie de l’aqueduc et l’interieur du château, puis une seconde grille de filtration et, finalement, franchir un petit barrage de plomb pour la decantation. L’edifice est couvert avec une coupole de maconnerie d’un diametre de 5,80 m, une des plus anciennes voutes de ce type. Partiellement endommage durant le seisme de l’an 62, le château d’eau fut restaure rapidement afin de distribuer l’eau urbaine a l’aide d’un reseau provisoire installe a la surface des trottoirs. Un bas-relief, evoquant le tremblement de terre, montre l’aspect de l’edifice avant sa restauration. Apres l’eruption du Vesuve, des recuperateurs, forant un trou dans la voute, ont derobe les elements de fer et de plomb de la filtration et de la tuyauterie.

Adam Jean-Paul. Aux origines du chemin de fer Paris-Rouen. Le rôle de la commission des travaux publics en 1839 . In: Études Normandes, 25e année, n°292, 1976. Aux origines du chemin de fer Paris-Rouen. Le rôle de la commission des travaux publics en 1839. pp. 1-12.