29 research outputs found

    The tax system and the financial crisis

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    This paper investigates the effects of the tax system on the economic factors that triggered the financial crisis. We examine three cases in which the tax regime interacted with these factors, reinforcing them. First, we focus on the taxation of residential building: while the importance of capital gains taxes is disputed, the deductibility of mortgage interest may have contributed to the financial crisis by creating some of the raw materials for the securitization industry. Second, a narrow perspective on the tax treatment, together with specific provisions, may have fostered performance-based remuneration of managers, resulting in overemphasis of short-term profitability and incentive to excessive risk-taking. Third, the securitization process, which played a key role in the outbreak of the financial crisis, was accompanied by opportunities for tax arbitrage and reduction of the overall tax wedge paid by investors, through offset of incomes that are ordinarily taxed at different rates; a de facto exemption of CDS premiums received by non-residents supplemented the tax arbitrage.taxation, financial crisis, housing market, stock options, securitization, credit default swaps

    Soft Perfusable Device to Culture Skeletal Muscle 3D Constructs in Air

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    Devices for in vitro culture of three-dimensional (3D) skeletal muscle tissues have multiple applications, including tissue engineering and muscle-powered biorobotics. In both cases, it is crucial to recreate a biomimetic environment by using tailored scaffolds at multiple length scales and to administer prodifferentiative biophysical stimuli (e.g., mechanical loading). On the contrary, there is an increasing need to develop flexible biohybrid robotic devices capable of maintaining their functionality beyond laboratory settings. In this study, we describe a stretchable and perfusable device to sustain cell culture and maintenance in a 3D scaffold. The device mimics the structure of a muscle connected to two tendons: Tendon−Muscle−Tendon (TMT). The TMT device is composed of a soft (E ∌ 6 kPa) porous (pore diameter: ∌650 ÎŒm) polyurethane scaffold, encased within a compliant silicone membrane to prevent medium evaporation. Two tendon-like hollow channels interface the scaffold with a fluidic circuit and a stretching device. We report an optimized protocol to sustain C2C12 adhesion by coating the scaffold with polydopamine and fibronectin. Then, we show the procedure for the soft scaffold inclusion in the TMT device, demonstrating the device’s ability to bear multiple cycles of elongations, simulating a protocol for cell mechanical stimulation. By using computational fluid dynamic simulations, we show that a flow rate of 0.62 mL/min ensures a wall shear stress value safe for cells (<2 Pa) and 50% of scaffold coverage by an optimal fluid velocity. Finally, we demonstrate the effectiveness of the TMT device to sustain cell viability under perfusion for 24 h outside of the CO2 incubator. We believe that the proposed TMT device can be considered an interesting platform to combine several biophysical stimuli, aimed at boosting skeletal muscle tissue differentiation in vitro, opening chances for the development of muscle-powered biohybrid soft robots with long-term operability in real-world environments

    Electrochemical degradation of methylene blue

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    This study was performed to compare the direct and indirect electrochemical oxidation of a synthetic solution containing methylene blue. The direct electrolysis was carried out using boron-doped diamond, while the indirect electrolyses were mediated by active chlorine electrogenerated on a TiRuO2 oxide anode. The effects of the operating factors that influence COD and colour removal were investigated for each type of electrolysis in order to find the optimum conditions. The experimental results revealed the suitability of both electrochemical processes for completely removing the COD and effectively decolourising the solution. In particular, in the indirect electrolysis, the oxidation of methylene blue only occurred in the presence of chloride ions that acted as redox mediators and the reaction was affected by the chloride concentration and applied current density, while in the direct electrolysis the oxidation took place by reaction with electrogenerated hydroxyl radicals and was favoured by high flow rates, meaning that the oxidation was a diffusion-controlled process. The comparison of the results showed that faster mineralisation and decolourisation of the solution was achieved by the indirect electrolysis, due to the high bleaching properties of active chlorine

    Influence of inorganic fillers on chemico-physical properties of epoxy-based materials

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    In the marine field epoxy-based materials are currently used to insulate the surface of the vessels, improve their surface finish and prepare it for the next painting treatments. A wide variety of fillers have been added to the epoxy resins in order to achieve an improvement of some properties, such as lightness, thermical insulation, hardness/tenderness of the surface. In this paper new hollow glass microspheres and Carbon NanoTubes (CNTs) were added to an epoxy matrix to obtain some new, different epoxy composites to compare to a traditional one. Their surface properties, cure behaviors, glass transition temperature, tensile strength and flexural strength were studied. The different hollow glass microspheres-filled composites showed similar behaviour, only with slight modifications of their final mechanical properties. On the other hand, the mechanical properties of the CNTs-filled composites were significantly different from those of neat epoxy resins. This variation could be understood on the analysis of the different interfacial interaction between the filler and the epoxy matrix in the composite
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