Tendances actuelles dans la caractérisation des obsidiennes pour les études de provenance

Les recherches de provenance des obsidiennes de sites paléolithiques et néolithiques connaissent actuellement une grande expansion, notamment par leur intégration dans les études de chaînes opératoires, qui nécessitent de déterminer l’origine de la matière première de séries importantes de pièces archéologiques. Il existe par ailleurs une forte demande de mesures peu à non destructives et éventuellement à effectuer in situ. D’où un certain nombre de développements méthodologiques récents. Le but de cette contribution est d’en présenter le statut actuel.Sourcing studies involving obsidians from Palaeolithic and Neolithic sites are presently undergoing a period of change, notably in terms of the average number of samples analyzed per project, due largely to their integration into the chaînes opératoires approach of lithic technologies. This can entail working with a large number of artifacts from an archaeological context. There is also an ever-increasing demand to employ quasi non-destructive characterization methods and completely non-destructive methods that eventually could be performed in situ. As such, recent methodological advances have taken several directions. The purpose of this short note is to give an overview of these approaches

The chemical structure of the Class 0 protostellar envelope NGC 1333 IRAS 4A

Context. It is not well known what drives the chemistry of a protostellar envelope, in particular the role of the stellar mass and the protostellar outflows on the chemical enrichment of such environments. Aims. We study the chemical structure of the Class 0 protostellar envelope NGC 1333 IRAS 4A in order to (i) investigate the influence of the outflows on the chemistry; (ii) constrain the age of our studied object; (iii) compare it with a typical high–mass protostellar envelope. Methods. In our analysis we use JCMT line mapping (360–373 GHz) and HIFI pointed spectra (626.01–721.48 GHz). To study the influence of the outflow on the degree of deuteration, we compare JCMT maps of HCO+ and DCO+ with non-LTE (RADEX) models in a region that spatially covers the outflow activity of IRAS 4A. To study the envelope chemistry, we derive empirical molecular abundance profiles for the observed species using the Monte Carlo radiative transfer code (RATRAN) and adopting a 1D dust density/temperature profile from the literature. We use a combination of constant abundance profiles and abundance profiles that include jumps at two radii (T ~ 100 K or T ~ 30 K) to fit our observations. We compare our best–fit observed abundance profiles with the predictions from the time dependent gas grain chemical code (ALCHEMIC). Results. We detect CO, 13CO, C18O, CS, HCN, HCO+, N2H+, H2CO, CH3OH, H2O, H2S, DCO+, HDCO, D2CO, SO, SO2, SiO, HNC, CN, C2H and OCS. We divide the detected lines in three groups based on their line profiles: a) broad emission (FWHM = 4–11 km s-1), b) narrow emission (FWHM< 4 km s-1), and c) showing absorption features. The broad component is indicative of outflow activity, the narrow component arises from dynamically quiescent gas (i.e. envelope) and the absorption is a result of infall motions or the presence of foreground material. Our maps provide information about the spatial and velocity structure of many of the molecules mentioned above, including the deuterated species, making it possible to distinguish between envelope and outflow structures also spatially. The derived abundance profiles are based only on the narrow component (envelope) of the species and are reproduced by a 1D pseudo-time-dependent gas-grain chemical model for the outer envelope, with the exceptions of HCN, HNC, CN. These species along with the CO abundance require an enhanced UV field which points towards an outflow cavity. The abundances with respect to H2 are 1 to 2 orders of magnitude lower than those observed in the high mass protostellar envelope (AFGL 2591), while they are found to be similar within factors of a few when they are estimated with respect to CO. Differences in UV radiation intensity may also be responsible for such chemical differentiation, but temperature differences seem a more plausible explanation, especially the absence of a freeze–out zone in the high mass case. The CH3OH modeled abundance profile points towards an age of ≥4 × 104 yr for IRAS 4A. The spatial distribution of H2D+ differs from that of other deuterated species (i.e. DCO+, HDCO and D2CO), indicating an origin from a colder layer (<20 K) in the foreground, which is not seen in any other tracer. Conclusions. The observed abundances can be explained by passive heating towards the high mass protostellar envelope, while the presence of UV cavity channels become more important toward the low mass protostellar envelope (e.g. CO, HCO+)

Tendances actuelles dans la caractérisation des obsidiennes pour les études de provenance

International audienceSourcing studies involving obsidians from Palaeolithic and Neolithic sites are presently undergoing a period of change, notably in terms of the average number of samples analyzed per project, due largely to their integration into the chaînes opératoires approach of lithic technologies. This can entail working with a large number of artifacts from an archaeological context. There is also an ever-increasing demand to employ quasi non-destructive characterization methods and completely non-destructive methods that eventually could be performed in situ. As such, recent methodological advances have taken several directions. The purpose of this short note is to give an overview of these approaches.Les recherches de provenance des obsidiennes de sites paléolithiques et néolithiques connaissent actuellement une grande expansion, notamment par leur intégration dans les études de chaînes opératoires, qui nécessitent de déterminer l’origine de la matière première de séries importantes de pièces archéologiques. Il existe par ailleurs une forte demande de mesures peu à non destructives et éventuellement à effectuer in situ. D’où un certain nombre de développements méthodologiques récents. Le but de cette contribution est d’en présenter le statut actuel

Pan-PPAR modulation effectively protects APP/PS1 mice from amyloid deposition and cognitive deficits.

peer reviewedAlzheimer's disease (AD) is a neurodegenerative condition that leads to neuronal death and memory dysfunction. In the past, specific peroxisome proliferator-activated receptor (PPAR)γ-agonists, such as pioglitazone, have been tested with limited success to improve AD pathology. Here, we investigated the therapeutic efficacy of GFT1803, a novel potent PPAR agonist that activates all the three PPAR isoforms (α/δ/γ) in the APP/PS1 mouse model in comparison to the selective PPARγ-agonist pioglitazone. Both compounds showed similar brain/plasma partitioning ratios, although whole body and brain exposure to GFT1803 was significantly lower as compared to pioglitazone, at doses used in this study. Oral treatment of APP/PS1 mice with GFT1803 decreased microglial activation, amyloid β (Aβ) plaque area, Aβ levels in sodium dodecyl sulfate- and formic acid-soluble fractions in a concentration-dependent manner. With a single exception of Aβ38 and Aβ40 levels, measured by ELISA, these effects were not observed in mice treated with pioglitazone. Both ligands decreased glial fibrillary acidic protein (GFAP) expression to similar extent and did not affect ApoE expression. Finally, GFT1803 increased insulin-degrading enzyme expression. Analysis of spatial memory formation in the Morris water maze demonstrated that both compounds were able to partially revert the phenotype of APP/PS1 mice in comparison to wild-type mice with GFT1803 being most effective. As compared to pioglitazone, GFT1803 (pan-PPAR agonist) produced both quantitatively superior and qualitatively different therapeutic effects with respect to amyloid plaque burden, insoluble Aβ content, and neuroinflammation at significantly lower whole body and brain exposure rates

First Mariner Mos1 Transposase Inhibitors

International audienceWe described chemical inhibitors of Mos1 transposition. Some were already known to affect a related prokaryotic transposase (Tn5) or HIV-1 integrase, whereas the other were new compounds in this field. The new compounds were all organized around a bis-(heteroaryl) maleimides scaffold. Their mechanism of action depended on the chemical substitutions on the scaffold. The cross-activity, between HIV-1 integrase and Mos1 transposase, of the new group of inhibitors showed that Mos1 transposase could constitute an excellent surrogate HIV-1 inhibitor screen

The Monte Arci obsidian: new fingerprinting approaches in provenance studies

Obsidians of the four Monte Arci geochemical groups relevant to Neolithic provenance studies were characterized by Mössbauer (MS) and infrared (IRS) spectroscopies, Raman microspectroscopy (RMS), magnetic properties (MP), electron spin resonance (ESR) and particle induced X-ray emission (PIXE). We show that these methods can discriminate, in addition to obsidians from other Western Mediterranean islands, the SA, SB and SC Sardinian groups (MS, MP, IRS) and eventually the SB1 and SB2 subgroups (MRS, ESR, PIXE).Ossidiane dei quattro principali gruppi geochimici del Monte Arci sono state caratterizzate con la spettroscopia Mössbauer (MS) e ad infrarosso (IRS), la microspettrometria Raman (RMS), le proprietà magnetiche (MP), la risonanza di spin elettronico (ESR) e la spettroscopia di emissione di raggi X indotta da protoni (PIXE). Si dimostra come questi metodi siano in grado di discriminare, oltre alle altre fonti insulari del Mediterraneo occidentale, i gruppi SA, SB ed SC (MS, MP, IRS) e i sottogruppi SB1 ed SB2 (MRS, ESR, PIXE) dell'ossidiana sarda

The Monte Arci obsidian: new fingerprinting approaches in provenance studies

Obsidians of the four Monte Arci geochemical groups relevant to Neolithic provenance studies were characterized by Mössbauer (MS) and infrared (IRS) spectroscopies, Raman microspectroscopy (RMS), magnetic properties (MP), electron spin resonance (ESR) and particle induced X-ray emission (PIXE). We show that these methods can discriminate, in addition to obsidians from other Western Mediterranean islands, the SA, SB and SC Sardinian groups (MS, MP, IRS) and eventually the SB1 and SB2 subgroups (MRS, ESR, PIXE).Ossidiane dei quattro principali gruppi geochimici del Monte Arci sono state caratterizzate con la spettroscopia Mössbauer (MS) e ad infrarosso (IRS), la microspettrometria Raman (RMS), le proprietà magnetiche (MP), la risonanza di spin elettronico (ESR) e la spettroscopia di emissione di raggi X indotta da protoni (PIXE). Si dimostra come questi metodi siano in grado di discriminare, oltre alle altre fonti insulari del Mediterraneo occidentale, i gruppi SA, SB ed SC (MS, MP, IRS) e i sottogruppi SB1 ed SB2 (MRS, ESR, PIXE) dell'ossidiana sarda

Identification of New Nonsteroidal RORα Ligands; Related Structure–Activity Relationships and Docking Studies

A high throughput screen was developed to identify novel, nonsteroidal RORα agonists. Among the validated hit compounds, the 4-(4-(benzyloxy)­phenyl)-5-carbonyl-2-oxo-1,2,3,4-tetrahydropyrimidine scaffold was the most prominent. Among the numerous analogues tested, compounds <b>8</b> and <b>9</b> showed the highest activity. Key structure–activity relationships (SAR) were established, where benzyl and urea moieties were both identified as very important elements to maintain the activity. Most notably, the SAR were consistent with the binding mode of the compound <b>8</b> (<i>S</i>-isomer) in the RORα docking model that was developed in this program. As predicted by the model, the urea moiety is engaged in the formation of key hydrogen bonds with the backbone of Tyr380 and Asp382. The benzyl group is located in a wide hydrophobic pocket. The structural relationships reported in this letter will help in further optimization of this compound series and will provide novel synthetic probes helpful for elucidation of complex RORα physiopathology

Réseau de lithothèques en Auvergne - Rhône-Alpes

Le programme collectif de recherche réseau de lithothèques en Auvergne-Rhône-Alpesexiste depuis 12 ans. Il est à l’initiative d’une synergie désormais reconnue sur l’origine des matièrespremières. Sa fonction est essentielle dans la consolidation d’une structure coopérative de rechercheaux échelles régionale et nationale. Démarche nécessaire, qui ouvre des perspectives nouvelles etirremplaçables dans le domaine des comportements techno-économiques, des circulations et desrapports intersites.Le présent rapport expose un état de l’art des actions mis en place afin de poursuivre de façon efficace lebut principal du programme : proposer aux préhistoriens un mode d’action pluridisciplinaire et évolutifqui une fois couplé à la technologie lithique permet une meilleure connaissance de la provenance etde la circulation des silex.Cette année le PCR a été financé par la DRAC Auvergne-Rhône-Alpes, les conseils généraux de l’Ain,de l’Isère, de la Savoie et la SARL Paléotime dans le cadre des opérations programmées. Grâce à cesfinancements et les contributions des membres de l’équipe, nous pouvons présenter un bilan qui vaservir de tremplin à une structure de plus en plus interconnectée. Au démarrage de cette nouvelletriennale le pôle recherche constitué au sein du PCR offre un cadre qui a toutes les qualités poursoutenir un travail de fonds, sur une conception unitaire et dynamiques des problématiques telles que: les lithothèques d’un territoire et la manière de les améliorer, l’inventaire des formations à silex, lacaractérisation des matériaux, la représentation des géoressources, la diffusion et la conservation desrésultats. Les axes désormais privilégiés ont été impulsés par deux actions majeures qui ont eu lieu auP.C.R. Réseau de lithothèques en Auvergne - Rhône-Alpes : rapport d’activité 20184cours de la précédente triennale. L’organisation en 2016 d’une école thématique à Nice par D. Binder(CNRS, CEPAM) et P. Fernandes (SARL Paléotime) et la réalisation d’une enquête nationale sur leslithothèques sous l’égide du CNRS, du Ministère de la Culture, de l’Inrap et de Paléotime (organisée parC. Bressy-Leandri). Ces deux initiatives ont permis d’identifier les attentes de la part de la communautédes préhistoriens. C’est à ces attentes que nous avons décidé de répondre : formation à la caractérisationdes silex - développement de l’outil lithothèque - normalisation des critères descriptifs - mutualisationde bases de données harmonisées sans oublier de garder le contact avec le territoire les acteursrégionaux.Pour cette triennale les membres du bureau ont donc choisi les axes suivants :• Axe 1 : formation à la caractérisation des silex, utilisation des nouvelles fiches ;• Axe 2 : développement de l’outil lithothèque, travail sur les lithothèques régionales ;• Axe 3 : maintenir un niveau d’activité en équilibre dans chacun des douze départements de lagrande région ;• Axe 4 : normalisation des critères descriptifs, élaboration d’une terminologie à l’échelle nationale ;• Axe 5 : applications au mobilier archéologique ;• Axe 6 : vers une mutualisation des bases de données et une valorisation des résultats, afin d’enrichirun pôle de compétences pluridisciplinaire régional intégrable au projet national.Les différents axes ainsi sélectionnés sont à la fois didactiques, patrimoniaux, recherche-développement,valorisation-diffusion. Ils témoignent du dynamisme d’une équipe soudée et de plus en plus interactiveau fil des ans. Ces axes sont complémentaires et doivent permettre à la fin de cette triennale de poserles bases d’une structure offrant la possibilité à toutes les personnes qui avaient exprimé ces attentesde bénéficier de méthodes et d’outils qui correspondent aux besoins de l’archéologie moderne.Ce programme réuni chaque année un groupe de participants convaincus de l’importance d’une telledémarche collective. Il est à l’origine d’une structure mêlant partage et harmonisation des bases dedonnées. Il est déjà partie prenante d’un projet national, le GDR SILEX coordonné par C. Bressy-Léandri.Il fait progresser les connaissances sur la question des comportements des Hommes préhistoriques parrapport aux géoressources. En parallèle, il a permis de créer de nouveaux liens au sein de la communautédes préhistoriens. Cette synergie facilite aujourd’hui les contacts et les échanges d’informations surune grande partie du territoire français (Auvergne-Rhône-alpes, PACA, Nouvelle aquitaine, Centre Valde-Loire, Ile de France). Elle est sans doute la meilleure solution pour tordre le cou aux problèmesrégulièrement posés par certains silex d’origine lointaine. La formation aux nouvelles méthodesd’inventaires ou de caractérisation doit permettre à toutes les personnes concernées d’utiliser unbagage commun et en cela participer au développement de la pétroarchéologie, de la tracéologie, dela taphonomie et de la géoarchéologie en améliorant le dialogue entre les acteurs de ces différentesdisciplines