Hardware and Software Transparency in the Protection of Programs Against SEUs and SETs

Processor cores embedded in systems-on-a-chip (SoCs) are often deployed in critical computations, and when affected by faults they may produce dramatic effects. When hardware hardening is not cost-effective, software implemented hardware fault tolerance (SIHFT) can be a solution to increase SoCs’ dependability, but it increases the time for running the hardened application, as well as the memory occupation. In this paper we propose a method that eliminates the memory overhead, by exploiting a new approach to instruction hardening and control flow checking. The proposed method hardens an application online during its execution, without the need for introducing any change in its source code, and is non-intrusive, since it does not require any modification in the main processor’s architecture. The method has been tested with two widely used architectures: a microcontroller and a RISC processor, and proven to be suitable for hardening SoCs against transient faults and also for detecting permanent faults.     

Modelling of the chemo–rheological behavior of thermosetting polymer nanocomposites

Epoxy/amine/montmorillonite nanocomposite systems are studied in this article. Both a thermo−kinetic analysis (performed using a differential scanning calorimeter) and a chemorheological characterization were carried out. The comparison of DSC thermograms has shown that the addition the nanofiller does not change the mechanism of crosslinking from a qualitative standpoint, but the nanoreinforcement seemed to produce an evident hindrance on the molecular mobility, which in turn influences the cure reactions. As none of the kinetic models available in literature was able to describe the cure behavior of the aforementioned materials, a new phenomenological model is proposed in this work, which considers the activation energy of the networking process a function of the degree of cure (rising exponentially towards infinity when thesystem approaches vitrification). The effects of the presence of the clay on the chemorheology of the composites was resumed as follows: the viscosity of the nanocomposite was higher at any temperature, furthermore the composite viscosity showed an higher heating sensitivity before networking and gelation occurred at lower degrees of cure, thus determining a narrower shape of the chemoviscosity behavior. A modified version of the classical Williams–Landel–Ferry (WLF) equation that took into account the gelation and the effects of crosslinking was uses as chemorheological model. Once the characteristic parameters of both the neat resin and the nanocomposite were found, the chemoviscosity models were integrated using a numerical algorithm, to check their ability to foresee the behavior of the systems during a dynamic cure process. A very good correspondence between the results and the experimental data was obtained. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Receptor–Receptor Interactions and Glial Cell Functions with a Special Focus on G Protein-Coupled Receptors

The discovery that receptors from all families can establish allosteric receptor–receptor interactions and variably associate to form receptor complexes operating as integrative input units endowed with a high functional and structural plasticity has expanded our understanding of intercellular communication. Regarding the nervous system, most research in the field has focused on neuronal populations and has led to the identification of many receptor complexes representing an important mechanism to fine-tune synaptic efficiency. Receptor–receptor interactions, however, also modulate glia–neuron and glia–glia intercellular communication, with significant consequences on synaptic activity and brain network plasticity. The research on this topic is probably still at the beginning and, here, available evidence will be reviewed and discussed. It may also be of potential interest from a pharmacological standpoint, opening the possibility to explore, inter alia, glia-based neuroprotective therapeutic strategies.     

MAO-A Inhibition by Metaxalone Reverts IL-1β-Induced Inflammatory Phenotype in Microglial Cells

Experimental and clinical studies have suggested that several neurological disorders are associated with the occurrence of central nervous system neuroinflammation. Metaxalone is an FDA-approved muscle relaxant that has been reported to inhibit monoamine oxidase A (MAO-A). The aim of this study was to investigate whether metaxalone might exert antioxidant and anti-inflammatory effects in HMC3 microglial cells. An inflammatory phenotype was induced in HMC3 microglial cells through stimulation with interleukin-1β (IL-1β). Control cells and IL-1β-stimulated cells were subsequently treated with metaxalone (10, 20, and 40 µM) for six hours. IL-1β stimulated the release of the pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), but reduced the anti-inflammatory cytokine interleukin-13 (IL-13). The upstream signal consisted of an increased priming of nuclear factor-kB (NF-kB), blunted peroxisome proliferator-activated receptor gamma (PPARγ), and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) expression. IL-1β also augmented MAO-A expression/activity and malondialdehyde levels and decreased Nrf2 mRNA expression and protein levels. Metaxalone decreased MAO-A activity and expression, reduced NF-kB, TNF-α, and IL-6, enhanced IL-13, and also increased PPARγ, PGC-1α, and Nrf2 expression. The present experimental study suggests that metaxalone has potential for the treatment of several neurological disorders associated with neuroinflammation.     

Antioxidant capacities,carotenoids and polyphenols evaluation of fresh and refrigerated peach and nectarine cultivars from Italy

Chemical–physical properties, colour parameters, antioxidant activities (AA), carotenoid and polyphenol levels (CL) in seven cultivars of yellow flesh peaches, five cultivars of yellow flesh nectarines and one cultivar of white flesh nectarines at harvest time and after 7 days of cold storage were evaluated. Peaches had major variability in flesh firmness (FF) and titratable acidity (TA) and lower soluble solid concentration (SSC) than nectarines. Evaluation of ground colour parameters, a*, b* and L*, showed that nectarines had a yellow-orange hue with high lightness, while peaches were darker, tending to red-green. Hydrophilic, lipophilic antioxidant activities of extracts (W-AA and L-AA), carotenoids and polyphenols levels (CL and PL) were evaluated and their relation with commercial maturation. The average of W-AA at harvest time was 11.0 TEAC, while the L-AA values at harvest time was on average higher in peaches (2.0 TEAC) than in nectarines (1.3 TEAC). The yellow flesh had higher amounts of total carotenoids (182.45 μg/100 g fw for peaches and 117.37 μg/100 g fw for yellow flesh nectarines). During cold storage, W-AA increased for nectarines (+22.9% in yellow flesh and +19.2% in white flesh) and peaches as well as polyphenolic compounds (+13.37%) while, contents of carotenoids decreased (−8.7%).     

Thermal and mechanical behavior of thermoplastic composites reinforced with fibers enzymatically extracted from Ampelodesmos mauritanicus

This work investigates the morphology, the thermal, and mechanical properties of technical fibers extracted from the Ampelodesmos mauritanicus (Diss) grass using a process that combines mechanical, mild chemical, and enzymatic steps. The structure and the thermal stability of Diss fibers make them suitable as a reinforcing filler in polymer composites, which was assessed by manufacturing biocomposites with improved stiffness and a tensile strength not degraded by Diss fibers when compared to those of a commodity polymer and a biodegradable one, namely polypropylene and poly(lactic acid). This work confirms that enzyme mixtures obtained from commercially available products of relatively low cost can represent a simple and environmentally friendly means to extract less common natural fibers. POLYM. ENG. SCI., 59:2418–2428, 2019. © 2019 Society of Plastics Engineers     

Development and performance analysis of PCL/silica nanocomposites for bone regeneration

In the present article, several developments of biocomposites containing silica nanoparticles intended for bone regeneration are reported. Nanocomposites of poly(ε-caprolactone) (PCL) and silica, in which either the silica nanoparticles or the PCL have been modified in order to improve interfacial adhesion through chemical graft between the phases are hereafter described. The composites are characterized with respect to their chemical–physical and mechanical properties. Their biocompatibility and capacity to induce the osteoblastic phenotype in human bone marrow mesenchymal stem cells have been assessed.     

Image processing and fractal box counting: user-assisted method for multi-scale porous scaffold characterization

Image analysis has gained new effort in the scientific community due to the chance of investigating morphological properties of three dimensional structures starting from their bi-dimensional gray-scale representation. Such ability makes it particularly interesting for tissue engineering (TE) purposes. Indeed, the capability of obtaining and interpreting images of tissue scaffolds, extracting morphological and structural information, is essential to the characterization and design of engineered porous systems. In this work, the traditional image analysis approach has been coupled with a probabilistic based percolation method to outline a general procedure for analysing tissue scaffold SEM micrographs. To this aim a case study constituted by PCL multi-scaled porous scaffolds was adopted. Moreover, the resulting data were compared with the outputs of conventionally used techniques, such as mercury intrusion porosimetry. Results indicate that image processing methods well fit the porosity features of PCL scaffolds, overcoming the limits of the more invasive porosimetry techniques. Also the cut off resolution of such IP methods was discussed. Moreover, the fractal dimension of percolating clusters, within the pore populations, was addressed as a good indication of the interconnection degree of PCL bi-modal scaffolds. Such findings represent (i) the bases for a novel approach complementary to the conventional experimental procedure used for the morphological analysis of TE scaffolds, in particular offering a valid method for the analysis of soft materials (i.e., gels); also (ii) providing a new perspective for further studies integrating to the structural and morphological data, fluid-dynamics and transport properties modelling.     

An experimental study on the conditions of safe oxidation of toluene with oxygen—carbon dioxide mixtures

The flammability limits of saturated vapours of toluene in oxygen—carbon dioxide mixtures have been measured up to 180°C and 10 atm using a directThe flammability data have been presented in a pressure versus temperature diagram. The convenience of this form of diagram to determine the conditions     

Effect of finite element choice in blunt crack band analysis

The previously developed method of element-wide blunt smeared crack bands, which allows an effective finite element analysis of cracks that are not fixed but propagate and do so in any direction, has so far been numerically studied and demonstrated only for the constant-strain triangular elements. Here this is accomplished for linear strain triangles and for all three methods developed in [1], including the methods of energy variation, of equivalent strength, and of fitting asymptotic series to nodal displacements. Meshes of greatly different sizes are shown to give again the same results except for a negligible error; this indicates satisfactory convergence. Accuracy of the stress intensity factor, compared to the exact solutions for sharp cracks, is found to be sufficient but not better than that achieved previously with constant strain triangles. However, the accuracy may well be better in case of concrete structures in which the element-wide crack band serves not merely as a convenient approximate representation of a sharp crack but as a better representation of the actual fracture process.