Triggering Amino Acid Detection by Atomistic Resolved Tunneling Current Signals in Graphene Nanoribbon Devices for Peptide Sequencing

The transversal tunneling current flowing across a narrow nanogap is employed for amino acid recognition in polypeptides during their translocation across the nanogap. An ideal device, consisting o..

First basin-wide experimental results on N2-fixation in the open Mediterranean Sea.

Mediterranean Sea presents several biogeochemical anomalies compared to the global ocean. Unbalanced N budget, high nitrate/phosphate ratios in subsurface waters and light isotopic signals in particulate and dissolved nitrogen have suggested a relevant occurrence of N2-fixation. This study presents, for the first time, N2-fixation rate measurements in the open Mediterranean Sea on a basin scale during early summer, compared to one site in the North Atlantic. Very low rates (0.052?0.031 nmols N l-1d-1) were observed in all sub-regions of the Mediterranean, unlike the higher values measured in the North Atlantic surface waters (0.300?0.115 nmols N l-1d-1). No evidence of phosphate limitation emerges from this study. Low N2-fixation rates associated to light isotopic composition of PON (from -2.10 to 4.11?) suggest that other light N sources, different from atmospheric N2, fuel the Mediterranean ecosystem

Nitrogen fixation in the Mediterranean Sea

The Mediterranean Sea is an oligotrophic basin characterized by low nutrient levels and unusually high NO3/PO4 molar ratios in the deeper layers, that reach the maximum (N/P = 28) in the Eastern Mediterranean. An external nitrogen source needs to be claimed in order to explain the nitrogen excess. Pantoja et al. (2002) found that the 15N/14N natural abundance in particulate and in dissolved inorganic nitrogen display low values, suggesting an important role of a "light" nitrogen source. Two hypotheses can be invoked: (i) nitrogen compounds from atmospheric deposition and/or(ii)atmospheric molecular nitrogen throughout nitrogen fixation . During TRANSMED oceanographic cruise carried out in the framework of Italian project VECTOR(June 2007), N2 fixation experiments have been carried out all over the Mediterranean Sea and outside the Gibraltar Strait. Surprisingly, very low rates (< 0.10 nmol N2*l-1*d-1) have been observed in different areas of the basin, while higher values have been observed in Atlantic Ocean according with literature data. These preliminary results suggest a major role for nitrogen atmospheric deposition in shaping the NO3/PO4 anomaly of the basin. Pantoja, S., D. J. Repeta, J. P. Sachs, and D. M. Sigman (2002). Stable isotope constraints on the nitrogen cycle of the Mediterranean Sea water column, Deep Sea Res., Part I, 4, 1609- 1621

Seasonal cycles of pH and carbonate system parameters in the southern Adriatic Sea during one year of VECTOR project

Within the VECTOR project (activity 8.1.2) the pH and other physical chemical parameters were acquired as seasonal time series from September 2007 to June 2008, at the AM1 station (in the centre of the Southern Adriatic Pit). The pH was measured by the spectrophotometric method (precision ? 0.003) and the results expressed on "total scale" at 25?C (pHT@25?C). In a few seasons also the total alkalinity (AT) was measured by potentiometric titration at 25?C (precision ? 3 Qmol/kg) and the results were checked against sea water certified as reference material (by dr. A.G. Dickson). The other derived parameters of the carbonate system (pCO2, DIC, lAr, lCa) were computed from pH, TA, salinity, temperature, SiO2, PO4 according to Lewis and Wallace 98. The pH seasonal variability was the highest in the upper layer (0-100 m), as clearly recognizable in fig 1a, b being the pH value mainly driven by biology during the productive seasons (from spring to late summer) or by mixing with deeper waters and exchange processes with atmosphere in winter. In the deeper layers (intermediate and bottom) the seasonal variability was lower but not negligible, probably driven by remineralization processes of dissolved and particulate organic matter locally produced, as suggested by Apparent Oxygen Utilization (AOU) and nitrate seasonal variabilities (fig. 1c, d, e, f). Generally, the highest differences of physical and biogeochemical properties can be observed in both the upper (0-100m ) and the intermediate (100-800 m) layers in September and June whereas during wintry season (January and February) variabilities were much lower. Through early to late summer season, the nutrients pH and dissolved inorganic carbon (TCO2) all suggest that both layers are strongly affected by biology (quite active primary production in the upper layer although in general the region has to be considered oligotrophic, and remineralisation processes in the intermediate layer). As confirmed by the good correlation with AOU and fluorescence. The vertical variabilities of such parameters are large, representing the 28 %, 0.4 %, -115 % of the total amount. Narrower changes can be observed passing from the intermediate to the bottom layer (800 - bottom) in January, February and June. A good correlation between changes of nutrients, pH, carbonate system and AOU is still observed, indicating the significant contribution of remineralisation processes to the final values. The physical and biogeochemical differences between the intermediate and the bottom layer further suggest that water masses of different origin filled these two layers. The persistence of inter layers variability through the year might suggest the absence of any abrupt change in the circulation scheme. The three forms of carbon dioxide in seawater (TCO2 aq, HCO3 -, CO3 = ) and the saturation states of calcite and aragonite were computed, from the experimental measures of pH and total alkalinity (reported in table 1) along the water column, in February June and October 2008. Values at surface show to be higher than the surface values of other oceanic regions, this is due to the higher alkalinity of the Mediterranean Sea, thus confirming peculiar characteristics of the carbonate system and the good saturation states of the Med Sea and southern Adriatic sea in particular

Espacements

Le thème de la temporalité, si important en psychanalyse, représente un de ces carrefours où se croisent d’autres concepts extraordinairement importants tels que le setting, la subjectivité, les théories du travail clinique, l’interprétation et la conception des facteurs thérapeutiques, l’institution psychanalytique. Nous abordons ici le concept de l’espace-temps en relation avec la théorie du champ analytique de Bion. L’hypothèse que nous avançons est que le champ est l’instrument conceptuel qui permet de moduler de façon plus fine et plus sûre la distance qui s’établit entre le patient et l’analyste pour atteindre et étendre l’unisson émotionnel qui, selon nous, est le facteur thérapeutique central

Gap size dependence of atomistic-resolved peptide bond signals by tunneling current across nano-gaps of graphene nano-ribbons

According to the recent literature, it has been demonstrated that the atomistic scale recognition of amino acids and peptide-bonds in polypeptides and proteins is in principle possible by measuring the tunneling current flowing across a narrow nano-gap in graphene nano ribbons during the peptide translocation. In this paper, we concentrate on the tunneling current signal properties measured for nano-gaps of different sizes. Using the non equilibrium Green function method based on the density functional theory, we have studied the tunneling current for larger gap sizes that can be actually realized according to the present state of the art sub-nanometer nano-pore and nano-gap technology. Also in these cases the peptide bond can be still recognized, the obtained signal being well within the measurable range of the current. The signal shapes undergo a change from a double peak feature per peptide bond for narrow gaps to a structured single peak signal per peptide bond for wider gaps. The reason is related to the different orbital overlap range of the two contributions giving rise to the original double peak signal for narrow gaps

Changing Styles, Affective Continuities and Psychic Containers: Corrado Govoni's Early Poetry

This article focuses on the relationship between the representation of femininity and aggressiveness (both stylistic and thematic) in Corrado Govoni's early twentieth-century works, from the erotic-symbolist sonnets of Le fiale (1903) [The Phials] to the Futurist-nationalist fury of L'inaugurazione della primavera (1915) [The Inauguration of Spring]. Drawing on a number of post-Kleinian psychoanalytical notions, it analyses recurrent discourse practices and narrative/rhetorical strategies in the representations of gender, sex and violence, highlighting their 'affective grammar'. The first section introduces the methodological framework, and then moves on to a contextualized overview of Govoni's early poetry. The second part undertakes a close reading of a particularly relevant sample of his work, the section from Le fiale entitled 'Vas luxuriae'. Both sections aim to show that the shift from the literary and cultural tropes of decadence to those of avant-garde nationalism is informed affectively by what, adopting Wilfred Bion's language, is termed a failure of psychic containment