Adenosine A2A receptor modulation of hippocampal CA3-CA1 synapse plasticity during associative learning in behaving mice

© 2009 Nature Publishing Group All rights reservedPrevious in vitro studies have characterized the electrophysiological and molecular signaling pathways of adenosine tonic modulation on long-lasting synaptic plasticity events, particularly for hippocampal long-term potentiation(LTP). However, it remains to be elucidated whether the long-term changes produced by endogenous adenosine in the efficiency of synapses are related to those required for learning and memory formation. Our goal was to understand how endogenous activation of adenosine excitatory A2A receptors modulates the associative learning evolution in conscious behaving mice. We have studied here the effects of the application of a highly selective A2A receptor antagonist, SCH58261, upon a well-known associative learning paradigm - classical eyeblink conditioning. We used a trace paradigm, with a tone as the conditioned stimulus (CS) and an electric shock presented to the supraorbital nerve as the unconditioned stimulus(US). A single electrical pulse was presented to the Schaffer collateral–commissural pathway to evoke field EPSPs (fEPSPs) in the pyramidal CA1 area during the CS–US interval. In vehicle-injected animals, there was a progressive increase in the percentage of conditioning responses (CRs) and in the slope of fEPSPs through conditioning sessions, an effect that was completely prevented (and lost) in SCH58261 (0.5 mg/kg, i.p.)-injected animals. Moreover, experimentally evoked LTP was impaired in SCH58261- injected mice. In conclusion, the endogenous activation of adenosine A2A receptors plays a pivotal effect on the associative learning process and its relevant hippocampal circuits, including activity-dependent changes at the CA3-CA1 synapse.This study was supported by grants from the Spanish Ministry of Education and Research (BFU2005-01024 and BFU2005-02512), Spanish Junta de Andalucía (BIO-122 and CVI-02487), and the Fundación Conocimiento y Cultura of the Pablo de Olavide University (Seville, Spain).B. Fontinha was in receipt of a studentship from a project grant (POCI/SAU-NEU/56332/2004) supported by Fundação para a Ciência e Tecnologia (FCT, Portugal), and of an STSM from Cost B30 concerted action of the EU

Heteroatom Donor‐Decorated Polymer‐Immobilized Ionic Liquid Stabilized Palladium Nanoparticles : Efficient Catalysts for Room‐Temperature Suzuki‐Miyaura Cross‐Coupling in Aqueous Media

Palladium nanoparticles stabilized by heteroatom donor‐modified polystyrene‐based polymer immobilized ionic liquids (PdNP@HAD‐PIILP; HAD‐PPh2, OMe, NH2, CN, pyrrolidone) are highly efficient catalysts for the Suzuki‐Miyaura cross‐coupling in aqueous media under mild conditions. Catalyst modified with phosphine was consistently the most efficient as it gave high yields across a range of substrates under mild conditions at low catalyst loadings. Incorporation of polyethylene glycol into the phosphine modified immobilised ionic liquid support improved catalyst efficacy by improving dispersibility and facilitating access to the active site. Moreover, each of the heteroatom modified catalysts was more active than the corresponding unsubstituted imidazolium‐based polystyrene benchmark as well as commercial samples of Pd/C. Catalyst generated in situ from either [PdCl4]@PPh2‐PIILP or its PEGylated counterpart [PdCl4]@PPh2‐PEGPIILP, by reduction with phenylboronic acid, outperformed their pre‐formed counterparts for the vast majority of substrates examined. The turnover frequency of 16,300 h−1 obtained at room temperature is one of the highest to be reported for palladium nanoparticle‐catalysed Suzuki‐Miyaura cross‐coupling between 4‐bromoacetophenone and phenylboronic acid in aqueous media under such mild conditions

Analysis of Electrical Aging Effects on AC High Frequency Motor Based on Exchange Market Algorithm Model Parameter Identification

The new wide-bandgap power semiconductor devices, such as gallium nitride and silicon carbide, have encouraged the development of power electronic converters with better efficiency, higher switching frequency, and smaller packages. However, such fast power converters are characterized by steep pulse width modulation voltage waveforms that cause increased electrical stress on the insulation system of the electric machine windings, eventually leading to premature failure. This poses a serious problem for high-speed applications where high system reliability and safety are required. Therefore, this work aims to show the effects of electrical aging on the high-frequency characteristics of electrical machines and then to assess the damage caused to the windings of a motor by such steep PWM waveforms. Finally, using a high-frequency model of the machine windings, it is possible to identify the parameters that are most affected by electrical stresses and thus assess the aging status of the insulation system

Regional-scale 3D modelling in metamorphic belts: An implicit model-driven workflow applied in the Pennine Alps

International audienceLeveraging a high resolution geological and structural dataset acquired over decades of fieldwork, we build the 3D structural model of a portion of the highly deformed core of the Alpine orogen, in the Northern Aosta Valley. The model represents tectonic contacts separating the tectono-metamorphic units outcropping along the section between Mont Blanc and Monte Rosa, and it covers an area of ca. 1500 km2. The input source data include original 1:10,000 geological surveys synthetised in a 1:75,000 tectonic map, and a dense database of structural stations. After a first orientation statistics study of the structural field database, our workflow develops through structural interpretation in vertical cross-sections that allow including in the modelling process structural drivers such as crosscutting relationships, interference patterns, kinematic constraints and fold morphology from detailed field studies. Three-dimensional interpolation on a tetrahedral mesh using the implicit Discrete Smooth Interpolator method follows, using also foliation and fold axes data as interpolation constraints. After describing the workflow and the model, we discuss the difficulties of modelling in polydeformed metamorphic complexes. In particular, we address the issue of modelling shear zones, refolded, isoclinal and/or recumbent folds and dense networks of faults, that characterise the geology of the Northern Aosta Valley

Geology of the Saint-Marcel valley metaophiolites (Northwestern Alps, Italy)

The geological map of the Saint-Marcel valley at the scale of 1:20,000 illustrates the tectonic setting of metaophiolites from the southern Aosta Valley, in the Italian side of the Western Alpine belt. The map highlights the sharp contact between the metaophiolitic basement and its metasedimentary cover, which mainly consists of quartzites, marbles, and calcschists. In spite of the Alpine tectonics, this contact is regarded as deriving from the original oceanic crust/sediments interface. Metaophiolites mostly consist of metabasalts hosting Fe\u2013Cu sulphide mineralisations, characterised by high-pressure metamorphic imprint. These rocks likely represent the shallowest portion of the Tethyan oceanic lithosphere created near the axis of the slow-spreading ridge where hydrothermal fluid circulation was active. Selected key-sections through metasediments reveal a consistent internal lithostratigraphy, in spite of the pervasive metamorphic and tectonic reworking acting during the Alpine evolution. Metasediments reflect various sedimentation episodes starting from pelagic and proximal settings to the onset of the orogenic stage. The Saint-Marcel valley metasediments thus reflect a changing in the sedimentation environments through time and space during the overall geologic evolution

55.10 : Carta geologica e note illustrative del transetto Val di Vizze - Fortezza (Alpi orientali)

20 p., 1 carta geologica allegata. Memorie di scienze geologiche, vol. 55, fasc. 10 (2003)

Geology of the Brenner Pass-Fortezza transect, Italian Eastern Alps

We present a 1:30,000 geological map resulting from detailed geostructural surveys carried out along the Italian segment of the design corridor for the Brenner Pass railway base tunnel (BBT), extending from Fortezza (Italy) to Innsbruck (Austria). The map covers the southern part of the Austroalpine-Penninic collisional wedge, the Periadriatic Fault System, associated Oligocene igneous bodies (Periadriatic magmatism) and part of the Southalpine basement. The Penninic Zone in the western Tauern Window is represented by the double domal structure of the Europe-derived Tux and Venediger-Zillertal basement and cover nappe system, capped by the ophiolitic Glockner nappe. The overlying Austroalpine nappe system is here represented by the polymetamorphic Merano-Mules basement and minor cover sheets. The Southern Alps domain includes the Bressanone Granite and pre-granite quartz-phyllites. Four Alpine ductile deformation phases have been recognized, followed by ductile-brittle shear zones, and finally brittle deformations along faults with extensional and strike-slip kinematics. The Quaternary is characterized by glacial deposits, large gravitational mass movements and landslides

Core-shell gold nanoparticles and gold-decorated metal oxides for gas sensing applications

Core-shell Gold nanoparticles exhibit tremendous catalytic properties and chemical reactivity, and have been extensively employed in a number of applications. Hereby we report different approaches to synthesize core-shell Gold nanoparticles; namely, wet-chemical reduction of Au-salts and Sacrificial Anode Electrolysis, with the intended use of Gold nanoparticles as catalysts and active layers on field effect capacitive devices for nitrogen oxides detection. In addition, different metal oxides are electrochemically decorated with nano-Gold to prepare metal-metal oxide nanocomposites. These nano-structured materials are fully characterized using TEM, SEM, and XPS, which reveal the formation of nanoscale Gold, and its successful decoration on metal oxide nanoparticles. The XPS results obtained after thermal annealing demonstrate that Gold nanoparticles are extremely stable even after 2h of annealing at high temperature (â\u89¥ 550 °C). © 2011 IEEE

Three-dimensional modelling of a complex metamorphic nappe stack from field survey only: the case study of the Aosta Valley (Italian NW-Alps)

International audienceThree-dimensional structural modelling of complex metamorphic settings is an extremely challenging task. In these settings, rocks sequences record multiple ductile and brittle events, leading for instance to refolded fold structures, isoclinal folds and dense network of faults. In this contribution, we build a 3D structural model of a portion of the highly deformed core of the Alpine orogeny in the North-Western Italian Alps, by using field data (1:10,000 geological map and a dense database of structural stations) as unique input source. Our model area has an extension of ca. 1,300 km<sup>2</sup> and a vertical elevation difference between the highest mountains (e.g., Cervino-Matterhorn) and the valley floors of ca. 4,000 meters, reflecting a truly three-dimensional dataset.</p> <p>Our workflow expects a first phase of orientation statistics study of the structural field database, followed by structural interpretation in vertical cross-sections and 3D interpolation using implicit surfaces and structural constraints. The implicit approach allows us to propagate field data and geological interpretation through mathematical constraints and to obtain structural interfaces reflecting observations.</p> <p>After introducing the new 3D structural model of the portion of the North-Western Alps, we discuss the difficulties related to geomodelling using input surface data only, by qualitatively addressing the uncertainty aspects of our workflow. We also focus on the range of geological and structural constraints that fieldwork allows us, reasoning on the distinction between observed and interpreted geological information