From Klein to anti-Klein tunneling in graphene tuning the Rashba spin-orbit interaction or the bilayer coupling

We calculate the transmission coefficient for a particle crossing a potential barrier in monolayer graphene with Rashba spin-orbit coupling and in bilayer graphene. We show that in both the cases one can go from Klein tunneling regime, characterized by perfect normal transmission, to anti-Klein tunneling regime, with perfect normal reflection, by tuning the Rashba spin-orbit coupling for a monolayer or the interplane coupling for a bilayer graphene. We show that the intermediate regime is characterized by a non-monotonic behavior with oscillations and resonances in the normal transmission amplitude as a function of the coupling and of the potential parameters.Comment: 9 pages, 5 figure

Quasi-particle dephasing time in disordered d-wave superconductors

We evaluate the low-temperature cutoff for quantum interference 1/tf induced in a d-wave superconductor by the diffusion enhanced quasiparticle interactions in the presence of disorder. We carry out our analysis in the framework of the non-linear sigma-model which allows a direct calculation of 1/tf, as the mass of the transverse modes of the theory. Only the triplet amplitude in the particle-hole channel and the Cooper amplitude with is pairing symmetry contribute to 1/tf. We discuss the possible relevance of our results to the present disagreement between thermal transport data in cuprates and the localization theory for d-wave quasiparticles

Localization transitions and mobility edges in coupled Aubry-Andr\'e chains

We study the localization transitions for coupled one-dimensional lattices with quasiperiodic potential. Besides the localized and extended phases there is an intermediate mixed phase which can be easily explained decoupling the system so as to deal with effective uncoupled Aubry-Andr\'e chains with different transition points. We clarify, therefore, the origin of such an intermediate phase finding the conditions for getting a uniquely defined mobility edge for such coupled systems. Finally we consider many coupled chains with an energy shift which compose an extension of the Aubry-Andr\'e model in two dimensions. We study the localization behavior in this case comparing the results with those obtained for a truly aperiodic two-dimensional (2D) Aubry-Andr\'e model, with quasiperiodic potentials in any directions, and for the 2D Anderson model.Comment: 12 pages, 18 figures, 2D Aubry-Andr\'e model included, published versio

Combining Revealed and Stated Preferences to design a new urban park in a metropolitan area of North-Western Italy

Inclusive and participatory decision-making is a sustainable option for governments and decision-makers to support real transformation and planning of policies and actions. Investigating and gathering the various views and opinions of stakeholders and citizens is particularly effective because it opens up a range of possibilities in co-constructing the city of the future. Among urban areas requiring planning, Urban Green Infrastructures (UGIs) represent spaces designed to improve the character of neighborhoods, as well as to increase the well-being of users. To achieve these goals, planners should adopt a design approach in which UGIs projects are shaped by local community concerns rather than by market conventions in urban design. Focusing on green recreational areas, this study employs an integrated approach combining Revealed (RP) and Stated Preferences (SP) to investigate citizens' preferences regarding urban parks. In particular, the experiment combines Travel Cost Method (TCM) and Discrete Choice Experiment (DCE) for supporting a requalification project in an ex-industrial area of Turin (Italy). In this way, it was possible to understand which facilities can contribute to increasing the citizens’ well-being and the overall efficiency of the UGIs provision and maintenance. The proposed methodology represents an operational and replicable procedure to support different renewal projects in which citizens' opinions are crucial for developing long-term sustainable socio-ecological plans and actions

Microemulsion-Based Gels for Lipase-Catalyzed Ester Synthesis in Organic Solvents

Microemulsions are clear, stable, isotropic mixtures of oil, water, and surfactant, frequently in combination with a cosurfactant. These systems are currently of interest to the pharmaceutical scientist because of their considerable potential to act as drug delivery vehicles by incorporating a wide range of drug molecules. The purpose of this work is to solubilize in AOT [sodium bis(2-ethylhexyl)sulphosuccinate] water-in-oil microemulsions at two different R-values the Chromobacterium viscosum (CV) lipase and lipoprotein lipase ex Pseudomonas and to use them to catalyze the lactonization of 16-hydroxyhexadecanoic acid at 40°C. CV lipase is also immobilized in gelatin-containing microemulsion-based gels (MBGs) with retention of catalytic activity. These lipase-containing MBGs proved to be novel solid-phase catalysts for use in apolar organic solvents. CV lipase-containing MBGs are used to synthesize, on a preparative scale, a variety of different esters under mild conditions

Synthesis by sol-gel route, chemical and biological characterization of hybrid material composed by Fe(II)C and poly(ε-caprolactone)

Abstract. Sol-gel route represents a valuable technique to obtain functional materials, in which organic and inorganic members are closely connected. Imbalance of the iron level in the body causes several diseases. In particular, the low level of iron, during pregnancy, is responsible of the iron deficiency anemia, and even of neurodegenerative diseases. The aim of this work was the synthesis of therapeutic systems, iron (II) based, by sol-gel method. In a SiO2 matrix were embedded polyethylene glycol (PCL 7, wt%) and ferrous citrate (Fe(II)C 6wt%) for drug delivery applications. Fourier Transform Infrared (FTIR) spectroscopy was used to study the interactions among different components in the hybrid materials. SiO2/Fe(II)C/PCL materials have been proposed as valuable antibacterial agents against Escherichia coli and Enterococcus faecalis

Partial Hydrogenation of Soybean and Waste Cooking Oil Biodiesel over Recyclable-Polymer-Supported Pd and Ni Nanoparticles

Biodiesel obtained through the transesterification in methanol of vegetable oils, such as soybean oil (SO) and waste cooking oil (WCO), cannot be used as a biofuel for automotive applications due to the presence of polyunsaturated fatty esters, which have a detrimental effect on oxidation stability (OS). A method of upgrading this material is the catalytic partial hydrogenation of the fatty acid methyl ester (FAME) mixture. The target molecule of the partial hydrogenation reaction is monounsaturated methyl oleate (C18:1), which represents a good compromise between OS and the cold filter plugging point (CFPP) value, which becomes too high if the biodiesel consists of unsaturated fatty esters only. In the present work, polymer-supported palladium (Pd-pol) and nickel (Ni-pol) nanoparticles were separately tested as catalysts for upgrading SO and WCO biodiesels under mild conditions (room temperature for Pd-pol and T = 100◦ C for Ni-pol) using dihydrogen (p = 10 bar) as the reductant. Both catalysts were obtained through co-polymerization of the metal containing monomer M(AAEMA)2 (M = Pd, Ni; AEEMA− = deprotonated form of 2-(acetoacetoxy)ethyl methacrylate)) with co-monomers (ethyl methacrylate for Pd and N,N-dimethylacrilamide for Ni) and cross-linkers (ethylene glycol dimethacrylate for Pd and N,N’-methylene bis-acrylamide for Ni), followed by reduction. The Pd-pol system became very active in the hydrogenation of C=C double bonds, but poorly selective towards the desirable C18:1 product. The Ni-pol catalyst was less active than Pd-pol, but very selective towards the mono-unsaturated product. Recyclability tests demonstrated that the Ni-based system retained its activity and selectivity with both the SO and WCO substrates for at least five subsequent runs, thus representing an opportunity for waste biomass valorization

Brain computer interface: studio, evoluzione ed applicazione dell’interfaccia neurale

This research aims to illustrate the progress in the field of Artificial Intelligence, in particular with an examination of the Brain Computer Interface (BCI), also known as Neural Interface. These devices, which have a distinctly interdisciplinary character, binds primarily the medical engineering field with that of neuro - cognitive research and have as main objective the rehabilitation or better support for therapeutic purposes with the so-called lock-in patients. First a brief focus on the neural interface story was outlined, with attention to early studies and recent developments that have characterized this protocol. Then we moved to the clarification of the neuro - psychological components that form the basis of a Neural Interface and therefore, detection systems and the particular brain frequencies that activate a BCI will be analyzed. Finally, we’ll discuss some of the most recent studies which have guided the BCI to new scope for developmen

Brain computer interface: studio, evoluzione ed applicazione dell’interfaccia neurale

This research aims to illustrate the progress in the field of Artificial Intelligence, in particular with an examination of the Brain Computer Interface (BCI), also known as Neural Interface. These devices, which have a distinctly interdisciplinary character, binds primarily the medical engineering field with that of neuro - cognitive research and have as main objective the rehabilitation or better support for therapeutic purposes with the so-called lock-in patients. First a brief focus on the neural interface story was outlined, with attention to early studies and recent developments that have characterized this protocol. Then we moved to the clarification of the neuro - psychological components that form the basis of a Neural Interface and therefore, detection systems and the particular brain frequencies that activate a BCI will be analyzed. Finally, we’ll discuss some of the most recent studies which have guided the BCI to new scope for developmen