3,427 research outputs found

    Modulation of human corticospinal excitability by paired associative stimulation in patients with amyotrophic lateral sclerosis and effects of Riluzole

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    BACKGROUND Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that causes an impairment in both the upper and lower motor neurons. The recent description of numerous non-motor signs points to an involvement of the neocortex networks that is more complex than was previously believed. Paired associative stimulation (PAS), a combination of transcranial magnetic stimulation (TMS) and peripheral nerve stimulation, can enhance motor output in the contralateral hand through an NMDA-mediated sensorimotor mechanism. OBJECTIVE To describe the effects of PAS on ALS patients before and after Riluzole intake compared with healthy subjects. METHODS PAS was used to detect differences between 24 newly-diagnosed ALS patients and 25 age-matched healthy controls. MEP amplitude from the abductor pollicis brevis was considered before PAS, immediately after (T0) and after 10 (T10), 20 (T20), 30 (T30) and 60 (T60) minutes. Statistical significance was calculated using RM-ANOVA. RESULTS In healthy controls, PAS significantly increased MEP amplitude at T10, T20 and T30 (p < 0.05). In ALS patients, a significant increase in MEP amplitude was also observed after 60 min (p < 0.05), thus demonstrating NMDA-mediated enhanced facilitatory plasticity. After two weeks of riluzole intake, no MEP amplitude increase was evident after PAS at any time point. In three monomelic-onset ALS patients, sensorimotor facilitation was evident only in the hemisphere corresponding to the affected side and appeared in the opposite hemisphere when the patients manifested contralateral symptoms. CONCLUSIONS PAS may be considered a useful tool when investigating NMDA-mediated neocortical networks in ALS patients and the modulation of such networks after anti-glutamatergic drug intake

    Photooxygenation of furans in water and ionic liquid solutions

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    Photooxygenation of differently functionalized furans is investigated in aqueous solutions and in ionic liquids [emim]Br and [bmim]BF4. The reaction is generally selective and the final products derive from rearrangement of the intermediate endoperoxides, depending mainly on the polarity and/or nucleophilic nature of the solvent

    Phase-Insensitive Scattering of Terahertz Radiation

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    The nonlinear interaction between Near-Infrared (NIR) and Terahertz pulses is principally investigated as a means for the detection of radiation in the hardly accessible THz spectral region. Most studies have targeted second-order nonlinear processes, given their higher efficiencies, and only a limited number have addressed third-order nonlinear interactions, mainly investigating four-wave mixing in air for broadband THz detection. We have studied the nonlinear interaction between THz and NIR pulses in solid-state media (specifically diamond), and we show how the former can be frequency-shifted up to UV frequencies by the scattering from the nonlinear polarisation induced by the latter. Such UV emission differs from the well-known electric-field-induced second harmonic (EFISH) one, as it is generated via a phase-insensitive scattering, rather than a sum- or difference-frequency four-wave-mixing process

    New energy downstream. Emerging business models and innovative best practices: an economic, institutional, and behavioral focus

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    Thanks to policy pressure and technological progress, modern energy systems are going through an increasing decentralization and decarbonization process. Digitalization and decarbonization, in this context, represent key enablers, as they unlock new opportunities of actors across the value chain (i.e., consumers, prosumers, retailers, traders, producers, network operators, and policy makers), providing them with new solutions. The combination of digital technologies and renewable energy solutions is already playing a pivotal role in the energy sector. The increasing attention toward clean energy sources, Internet of Things, Artificial Intelligence, Big Data, Cloud, 5 G, and Blockchain technologies are influencing changes both in energy companies’ value creation strategies and in customer behavior as well as in policy and regulatory frameworks. This transition will define the economic and legal environment able to accommodate an ever-increasing number and variety of alternative business models and new solutions. All these new aspects are expected to have an impact on long-time established roles, particularly by creating trust and empowering consumers on one side, and by disrupting traditional business models on the other. Ideally, this transformative process should be able to set out cost-effective and economically productive pathway, resulting in a clean, dynamic, and resilient energy economy dominated by renewables – while ensuring stable and affordable energy supplies, providing universal energy access, and enabling robust economic growth

    Bringing Down the Barriers: American Laws That Impede Trade With the CIS

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    It is necessary first to establish whether current trade restrictions apply to all former constituent parts of the Soviet Union or only to Russia. Second, the American-Russian trade relationship resembles a minefield. Some of the most powerful trade restrictions remain firmly in place. Others have been defused. This article will attempt to provide some guidance through the minefield. Finally, attention will be given to pending legislation that affects trade with Russia. Hopefully, this analysis will provide some insight into: (1) the past U.S. trade with the former Soviet Union; (2) where the relationship is now; and (3) what direction it should go in light of the demise of the USSR and the rise of the CIS and other independent states

    Development of smooth finishes in electrostatic fluidized bed (EFB) coating process of high-performance thermoplastic powders (PPA 571 H)

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    This paper deals with the analysis of the evolution of the surface morphology of metal substrates coated with high-performance thermoplastic powders, namely PPA 571 H, by using electrostatic fluidized bed (EFB) process. Attention has been particularly focused on the relationship between baking time and temperature of EFB coated substrates and the morphological characteristics of the resulting polymeric films. First, thermal behaviour of PPA 571 H polymeric powders was characterized by using standard calorimetric techniques. Accordingly, PPA 571 H melting kinetic was experimentally deduced. Based upon experimental findings, predictive analytical model was also developed and employed to trace 'iso-conversion' curves out. Second, metal substrates, made from low carbon steel (AISI 1040), were EFB coated and baked at several baking time and temperatures. Combined analyses of scanning electron and confocal microscopes were led to measure the evolution of the films surface morphology under different baking conditions. Accordingly, a relationship between film morphologies and melting degree was sought. Consistent trends of roughness parameters versus baking parameters were found, with smoother finishes of the polymeric films being achieved for higher degrees of melting, that is, for higher baking temperature and time. Full maps and related analytical models of the finishing levels according to baking parameters were also built up, hence providing first useful indications to powder coaters on how to best deal with their settings. © 2006 Elsevier B.V. All rights reserved

    Pressure shock fronts formed by ultra-fast shear cracks in viscoelastic materials

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    Spontaneously propagating cracks in solids emit both pressure and shear waves. When a shear crack propagates faster than the shear wave speed of the material, the coalescence of the shear wavelets emitted by the near-crack-tip region forms a shock front that significantly concentrates particle motion. Such a shock front should not be possible for pressure waves, because cracks should not be able to exceed the pressure wave speed in isotropic linear-elastic solids. In this study, we present full-field experimental measurements of dynamic shear cracks in viscoelastic polymers that result in the formation of a pressure shock front, in addition to the shear one. The apparent violation of classic theories is explained by the strain-rate-dependent material behavior of polymers, where the crack speed remains below the highest pressure wave speed prevailing locally around the crack tip. These findings have important implications for the physics and dynamics of shear cracks such as earthquakes
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