Neural Circuits Underlying Motor Facilitation during Observation of Implied Motion

In the present study we used single and paired-pulse Transcranial Magnetic Stimulation (TMS) to evaluate the effect of implied motion on primary motor cortex microcircuits. We found that observation of the implied motion of a static image increases MEP amplitude and reduces short-interval intracortical inhibition (SICI), without significant modulation of intracortical facilitation and sensory-motor integration. Our results add to the existing literature on the activation of the observation-execution matching system and describe a selective modulation of GABAergic cortical microcircuits during observation of implied motion

FROM MASTER CURVES FOR THE MECHANICAL REINFORCEMENT OF RUBBER BASED NANOCOMPOSITES TO LIGHTWEIGHT MATERIALS

sp2 carbon allotropes are efficient reinforcing fillers for rubber materials. CB is made by primary nanometric particles, fused together to form micron-size aggregates. Nanofillers bring individual nanometric particles into the polymer matrix: they have large surface area and hence large interfacial area with the polymer matrix. Nanofillers such as graphene related materials (GRM) and carbon nanotubes (CNT) have anisometric nature. Nanoplatelets and nanofibers achieve the largest values of interfacial area and can exhibit preferential orientation inside a matrix, leading to anisotropic properties. In this work, the reinforcing ability and the anisotropy of mechanical reinforcement of CB, CNT and GRM1 in rubber matrices such as poly(1,4-cis-isoprene) and poly(styrene-co-butadiene) was investigated. Correlation was studied between mechanical reinforcement and filler-polymer interfacial area (i.a.), defined as the product Ai·ρ·φ, where Ai is the surface area (assumed to be equal to BET surface area), ρ is the filler density and φ is the filler volume fraction2. Samples based on nanofillers were transversally isotropic: properties were very similar inside the sheet plane and very different in the orthogonal direction. The initial modulus in the direction orthogonal to the sheet plane, was taken as the index of mechanical reinforcement. It was observed that for i.a. value up to about 27 μm-1, experimental points due to CNT, CB, as well as to hybrid filler systems, lie on a sort of master curve. Thanks to the above mentioned master curves, composites were designed and prepared with lower density

Microstructural and electrical properties of (Sr,Ba)Nb2O6 thin films grown by pulsed laser deposition

Strontium barium niobate thin films have been deposited by pulsed laser deposition on (111)-textured Pt films, p-doped Si(I 00) and Nb doped STO (SrTiO3) single crystals. The deposition parameters were optimized for obtaining phase pure (001)-oriented films from stochiometric targets. The samples were annealed in oxygen to improve top electrode adhesion and reduce oxygen vacancies. The SBN/substrate interfaces were investigated by means of TEM combined with EDAX chemical analysis. Growth on silicon resulted in the formation of a few nm thick SiO2 interface layer. Epitaxial growth has been obtained on STO. A broad relaxor-type or diffuse phase transition occurs around -50 degreesC well below the transition temperature of single crystals. A second dielectric anomaly is observed around 80 degreesC, which, however, disappears after annealing in O-2. Above,the dielectric loss increases exponentially due to presumed leakage by ion conduction. Hysteresis loops at room temperature confirm relaxor-type behaviour with a saturation polarization of 18 muC/cm(2) and a weak hysteresis with a coercive field of 50 kV/cm. (C) 2003 Elsevier Ltd. All rights reserved