Prebiotic Organic Globules

Analogs of organic globules observed in carbonaceous chondrite meteorites and in interplanetary dust particles and of rod to spherical structures observed in terrestrial archean microstructures have been synthesized in our experiments conducted with proton irradiation on a mixture of simple inorganic constituants, CO, N2 and H2O. Our analyses of these laboratory organic globules show that the proton irradiation residue contains proteinous and non-proteinous amino acid precursors. On the basis of morphology, of hydrothermal and mineral environment, we suggest that the meteoritic organic globules and the archean carbon microstructures could be composed of amino acid precursors

Multiscale Granger causality analysis by \`a trous wavelet transform

Since interactions in neural systems occur across multiple temporal scales, it is likely that information flow will exhibit a multiscale structure, thus requiring a multiscale generalization of classical temporal precedence causality analysis like Granger's approach. However, the computation of multiscale measures of information dynamics is complicated by theoretical and practical issues such as filtering and undersampling: to overcome these problems, we propose a wavelet-based approach for multiscale Granger causality (GC) analysis, which is characterized by the following properties: (i) only the candidate driver variable is wavelet transformed (ii) the decomposition is performed using the \`a trous wavelet transform with cubic B-spline filter. We measure GC, at a given scale, by including the wavelet coefficients of the driver times series, at that scale, in the regression model of the target. To validate our method, we apply it to publicly available scalp EEG signals, and we find that the condition of closed eyes, at rest, is characterized by an enhanced GC among channels at slow scales w.r.t. eye open condition, whilst the standard Granger causality is not significantly different in the two conditions.Comment: 4 pages, 3 figure

Prebiotic Organic Microstructures

Micro- and sub-micrometer spheres, tubules and fiber-filament soft structures have been synthesized in our experiments conducted with 3 MeV proton irradiations of a mixture of simple inorganic constituents, CO, N2 and H2O. We analysed the irradiation products, with scanning electron microscopy (SEM) and atomic force microscopy (AFM). These laboratory organic structures produced wide variety of proteinous and non-proteinous amino acids after HCl hydrolysis. The enantiomer analysis for D-, L- alanine confirmed that the amino acids were abiotically synthesized during the laboratory experiment. Considering hydrothermal activity, the presence of CO2 and H2, of a ferromagnesian silicate mineral environment, of an Earth magnetic field which was much less intense during Archean times than nowadays and consequently of a proton excitation source which was much more abundant, we propose that our laboratory organic microstructures might be synthesized during Archean times. We show similarities in morphology and in formation with some terrestrial Archean microstructures and we suggest that some of the observed Archean carbon spherical and filamentous microstructures might be composed of abiogenic organic molecules. We further propose a search for such prebiotic organic signatures on Mars. This article has been posted on Nature precedings on 21 July 2010 [1]. Extinct radionuclides as source of excitation have been replaced by cosmic radiations which were much more intense 3.5 Ga ago because of a much less intense Earth magnetic field. The new version of the article has been presented at the ORIGINS conference in Montpellier in july 2011 [2] and has since been published in Origins of Life and Evolution of Biospheres 42 (4) 307-316, 2012. 
DOI: 10.1007/s11084-012-9290-5 

&#xa

Characterization of Carbonaceous Materials by Correlated Electron and Optical Microscopy and Raman Microspectroscopy

Carbonaceous materials differ according to their chemical composition (types of heteroatoms), their structure and their microtexture. So, it is interesting to find methods for characterizing them. We choose to correlate data from Raman microspectroscopy, optical microscopy and transmission electron microscopy. First, we use both graphitizable or non-graphitizable reference carbon series of simple chemical composition in order to follow the structural transformation of the carbonaceous materials according to the evolution of these data throughout heat-treatment of these samples. Then, the coals of different ranks are studied. The Raman results are correlated with those from electron microscopy, particularly by plotting, for the graphitizable series, the diameter of the aromatic layers La (determined from lattice fringes and 11 dark-field) versus the specific surface of the Raman band characteristic of the defects centered at about 1350 cm-1 (ratio between surfaces of this band and the whole spectrum). For the coals, the half-maximum width of the band at about 1600 cm-1 has been plotted versus the reflectance. We conclude that the evolution of carbonaceous materials, throughout heat-treatments or natural processes, is possible only because different types of defects are progressively removed. These defects are heteroatoms, tetrahedral carbons, isolated and crosswise basic structural units or BSU (one, two or three stacked in parallel polyaromatic structures, less than 10 A in size) and defects in aromatic layers. The elimination of these defects permits the rearrangement of the BSUs and the establishment of an organization which can possibly reach the triperiodic order according to the series

Organic Analysis of Peridotite Rocks from the Ashadze and Logatchev Hydrothermal Sites

This article presents an experimental analysis of the organic content of two serpentinized peridotite rocks of the terrestrial upper mantle. The samples have been dredged on the floor of the Ashadze and Logatchev hydrothermal sites on the Mid-Atlantic Ridge. In this preliminary analysis, amino acids and long chain n-alkanes are identified. They are most probably of biological/microbial origin. Some peaks remain unidentified

Benjamin Appert en Grèce : le rêve d'une prison philanthropique

Benjamin Appert was a French philanthropist during the Restoration and the reign of Louis-Philippe. He was famous enough for Stendhal to make him a character in his novel Le Rouge et le Noir. The writer describes him as a prison visitor, his principal activity; but he also took an interest in mutual teaching. After this period, he sank into oblivion. The only people who know about him are the specialists of penal and educational issues. His track was lost in 1855 when he left to Greece.At that time, we take over. We will follow him closely, thanks to an exceptional document, the collection of notes he published under the title of Journey in Greece. What did he go to Greece for ? He did not only want to visit prisons, schools, hospitals and barracks, so as to draw up a survey and propose reforms to clean up a country subjected to robbery, but he aimed to achieve a plan he had been nurturing for a long time, the settlement of a model penal colony he tried to establish in Modon (Methoni).Was it a utopia? That is the question which runs all through our research. Of course the answer depends on the meaning of the word. During the first half of the XIXth century, a time brimming with social utopias, could we rank Benjamin Appert on the same level as Saint-Simon or Fourier? That will be our subject. We can already consider his story in Greece as an excellent example of the connections which took place between West and East, heavily loaded with misunderstanding, prejudice and idealism. An example we could meditate over.Benjamin Appert fut, sous la Restauration et le règne de Louis-Philippe, un philanthrope suffisamment célèbre pour que Stendhal en fasse un personnage de roman, dans Le Rouge et le Noir. L'écrivain le campe en visiteur de prisons, ce qui effectivement constituait une grande part de ses activités, l'autre concernant l'enseignement mutuel. Depuis, Appert a sombré dans l'oubli. Il n'y a plus guère que les spécialistes de la question pénitentiaire et de l'école pour connaître son existence, et l'on perd sa trace en 1855, date de son départ pour la Grèce.C'est en ce point que nous prenons le relais. Nous lui emboîterons le pas, grâce à l'exceptionnel document que constitue le recueil de notes publié par lui sous le titre : Voyage en Grèce. Qu'allait-il faire en Grèce ? Non seulement visiter les prisons, les écoles, les hôpitaux, les casernes, pour dresser un état des lieux et proposer des réformes, dans le but d'assainir un pays en proie au brigandage, mais surtout réaliser un projet mûri de longue date, la fondation d'une colonie pénitentiaire modèle, qu'il tentera d'implanter à Modon (Méthoni).S'agissait-il d'une utopie ? Telle est la question qui court au long de cette recherche. La réponse dépend évidemment du sens que l'on donne à ce terme. En ce temps des utopies sociales que constitue la première moitié du XIXe siècle, peut-on mettre Benjamin Appert au rang d'un comte de Saint-Simon ou d'un Fourier ? C'est ce que nous étudierons. D'ores et déjà, on peut voir dans son histoire en Grèce un excellent exemple des rencontres qui eurent lieu entre Occident et Orient, toutes chargées de malentendus, de préjugés et d'idéalisme. Exemple que nous pouvons méditer

Microcharacterization of Fluid Inclusions in Minerals by Raman Microprobe

Fluids trapped in inclusions in minerals are micro-amounts of ore-forming media composed of water, dissolved salts, gases and sometimes liquefied gases, liquid, hydrocarbons and solids. The aim of this paper is to summarize the contribution of the Raman scattering microspectrometry to the knowledge of fluid inclusions. After a review of the composition of fluid inclusions and a short presentation of microthermometrical investigations, a description of the Raman microprobe is given. Applications are reviewed; identification of ionic species dissolved in aqueous phase, characterization of gases of C-O-H-N-S system, identification of solids and non aqueous liquids. The complementary characteristics of Raman microanalysis and microthermometry are underlined. The last section is devoted to comparisons with other microprobes from the point of view of chemical and mineralogical analysis of fluid inclusions

0230: Effectiveness of switching Prasugrel's ‘low responders’ to ticagrelor after acute coronary syndrome

AimsThis study aimed to assess the effectiveness and safety of switching from Prasugrel to Ticagrelor patients identified as Prasugrel low-responders one month after ACS.Methods and results540 patients admitted for ACS with coronary stent implantation and discharged on Prasugrel 10mg were screened. Prasugrel response was assessed one month after discharge using Platelet Reactivity Index Vasodilatator Stimulated Phosphoprotein (PRI VASP). High on-Treatment Platelet Reactivity (HTPR) was defined as VASP>50%. Patients with HTPR were enrolled and switched to Ticagrelor 90 mg twice a day. They were re-tested a month later. Primary endpoint was defined as: comparison of degree of platelet inhibition and incidence of HTPR one month after switching to Ticagrelor in patients with HTPR on Prasugrel therapy. The safety endpoint was the incidence of bleedings under Ticagrelor as compared with Prasugrel therapy, using the Bleeding Academic Research Consensus definition.Between March 2010 and November 2013, 19 patients were defined as HTPR on Prasugrel 10 mg one month after ACS, with a mean VASP of 59,3%. Among these patients, 14 were switched to Ticagrelor 180 mg daily and, at one month, we observed a significant decrease in PRI VASP, with a mean value at 19.6% (p<0.001). No patients remained HTPR and 4 patients (28.4%) were identified as Very Low on-Treatment Platelet Reactivity (VLTPR) (VASP<10%). No ischemic events were reported after switching, while 3 patients (21%) suffered from bleeding complications (2 BARC1 and 1 BARC2 bleedings) during Ticagrelor therapy.ConclusionSwitch to Ticagrelor in Prasugrel's “low responders” patients is an effective strategy, leading to an adequate platelet inhibition in a large majority of patients. This biological tailored approach could be useful in preventing ischemic complications, in this specific high risk population, potentially increasing bleeding risk. This hypothesis needs to be confirmed in large clinical studies.Abstract 0230 – Figur

Effect of non-invasive vagus nerve stimulation on resting-state electroencephalography and laser-evoked potentials in migraine patients : mechanistic insights

A recent multicenter trial provided Class I evidence that for patients with an episodic migraine, non-invasive vagus nerve stimulation (nVNS) significantly increases the probability of having mild pain or being pain-free 2 h post-stimulation. Here we aimed to investigate the potential effect of nVNS in the modulation of spontaneous and pain related bioelectrical activity in a subgroup of migraine patients enrolled in the PRESTO trial by using resting-state electroencephalography and trigeminal laser-evoked potentials (LEPs). LEPs were recorded for 27 migraine patients who received active or sham nVNS over the cervical vagus nerve. We measured power values for frequencies between 1–100 Hz in a resting-state condition and the latency and amplitude of N1, N2, and P2 components of LEPs in a basal condition during and after active or sham vagus nerve stimulation (T0, T1, T2). The P2 evoked by the right and the left trigeminal branch was smaller during active nVNS. The sham device also attenuated the P2 amplitude evoked by the left trigeminal branch at T1 and T2, but this attenuation did not reach significance. No changes were observed for N1 amplitude, N1, N2, P2 latency, or pain rating. nVNS induced an increase of EEG power in both slow and fast rhythms, but this effect was not significant as compared to the sham device. These findings suggest that nVNS acts on the cortical areas that are responsible for trigeminal pain control and pave the ground for future studies aimed at confirming the possible correlations with clinical outcomes, including the effect on symptoms that are directly correlated with trigeminal pain processing and modulation