Nella prima parte del contributo, dopo aver velocemente illustrato il ruolo del diritto amministrativo nella gestione della complessità sociale, si esaminano l’uso degli algoritmi all’interno delle ...amministrazioni pubbliche, le problematiche che questi hanno fatto emergere e le soluzioni che letteratura e giurisprudenza hanno offerto. In un secondo momento, invece, per superare il binarismo tra accettazione e rifiuto della digitalizzazione dei procedimenti amministrativi si affronta il tema in un’ottica più ampia, quella, appunto, “dell’amministrazione pubblica degli algoritmi”. In questa prospettiva si esamina l’opportunità di interpretare alcuni istituti del Codice dell’amministrazione digitale, come il riuso del software, quali strumenti di coordinamento informatico, per sviluppare la digitalizzazione dell’amministrazione pubblica contemperando le esigenze di differenziazione, da una parte, e preservando la riuscita della transizione digitale, dall’altra.
Shape‐memory polymers (SMPs) are morphologically responsive materials with potential for a variety of biomedical applications, particularly as devices for minimally invasive surgery and the delivery ...of therapeutics and cells for tissue engineering. A brief introduction to SMPs is followed by a discussion of the current progress toward the development of SMP‐based biomaterials for clinically relevant biomedical applications.
Stimuli‐responsive shape‐memory polymer‐based materials have great potential for a variety of biomedical applications. Their development toward use as functional biomedical devices for drug delivery, minimally invasive surgery and tissue engineering are discussed, particularly with a view to their progress toward clinical relevance.
The development of new flexible and stretchable sensors addresses the demands of upcoming application fields like internet‐of‐things, soft robotics, and health/structure monitoring. However, finding ...a reliable and robust power source to operate these devices, particularly in off‐the‐grid, maintenance‐free applications, still poses a great challenge. The exploitation of ubiquitous temperature gradients, as the source of energy, can become a practical solution, since the recent discovery of the outstanding thermoelectric properties of a conductive polymer, poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS). Unfortunately the use of PEDOT:PSS is currently constrained by its brittleness and limited processability. Herein, PEDOT:PSS is blended with a commercial elastomeric polyurethane (Lycra), to obtain tough and processable self‐standing films. A remarkable strain‐at‐break of ≈700% is achieved for blends with 90 wt% Lycra, after ethylene glycol treatment, without affecting the Seebeck voltage. For the first time the viability of these novel blends as stretchable self‐powered sensors is demonstrated.
Stretchable self‐powered sensors are developed via blending elastomeric polyurethane (Lycra) with the best current organic thermoelectric material, poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS). In doing so, the main technological constrains of PEDOT:PSS, namely brittleness, processability, and costs, have, at the same time, been overcome. An unprecedented strain at break (≈700%) is reached, while maintaining high electrical conductivity (≈79 S cm−1) and Seebeck coefficient (≈16 µV K−1).
The concept of high entropy ceramics opens up the possibility to optimise the properties of relaxor ferroelectrics with Aurivilius phase structures. In this paper, two new multi-element substituted ...Aurivillius phase ceramics, (Ca0.25Sr0.25Ba0.25Pb0.25)Bi2Nb2O9 and (Ca0.2Sr0.2Ba0.2Pb0.2Nd0.1Na0.1)Bi2Nb2O9 are prepared. Both ceramics are single phase, exhibiting orthorhombic symmetry with space group A21am at room temperature. The frequency dependence of the temperature of the dielectric permittivity peak, Tm, shows relaxor behaviour for both ceramics. Multi-domain configurations, including long range ordered ferroelectric domains and nano domains, were observed using piezoresponse force microscopy (PFM). Under an applied DC field, the nano domains irreversibly transformed to micro-meter sized domains, which is consistent with the Vogel-Fulcher Law fitted results that show that the freezing temperatures of the two ceramics are above room temperature. Their improved piezoelectric constant is attributed to their low coercive fields, which are related to the multi domain configurations in the Aurivillius phase relaxor ferroelectrics.
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•Two single phase BaBi2Nb2O9 - based Aurivillius phase ceramics have been developed using the high entropy ceramic concept.•The developed ceramics are relaxor ferroelectrics with dielectric loss six times lower compared with BaBi2Nb2O9.•The freezing temperatures of the developed BaBi2Nb2O9 based ceramics increased from −155 °C to above 300 °C.•The optimized performance of the developed ceramics is related to their multi-domain configurations.
The ability to control the placement of individual molecules promises to enable a wide range of applications and is a key challenge in nanoscience and nanotechnology. Many biological interactions, in ...particular, are sensitive to the precise geometric arrangement of proteins. We have developed a technique which combines molecular-scale nanolithography with site-selective biochemistry to create biomimetic arrays of individual protein binding sites. The binding sites can be arranged in heterogeneous patterns of virtually any possible geometry with a nearly unlimited number of degrees of freedom. We have used these arrays to explore how the geometric organization of the extracellular matrix (ECM) binding ligand RGD (Arg-Gly-Asp) affects cell adhesion and spreading. Systematic variation of spacing, density, and cluster size of individual integrin binding sites was used to elicit different cell behavior. Cell spreading assays on arrays of different geometric arrangements revealed a dramatic increase in spreading efficiency when at least four liganded sites were spaced within 60 nm or less, with no dependence on global density. This points to the existence of a minimal matrix adhesion unit for fibronectin defined in space and stoichiometry. Developing an understanding of the ECM geometries that activate specific cellular functional complexes is a critical step toward controlling cell behavior. Potential practical applications range from new therapeutic treatments to the rational design of tissue scaffolds that can optimize healing without scarring. More broadly, spatial control at the single-molecule level can elucidate factors controlling individual molecular interactions and can enable synthesis of new systems based on molecular-scale architectures.
DNA is programmed to hierarchically self-assemble into superstructures spanning from nanometer to micrometer scales. Here, we demonstrate DNA nanosheets assembled out of a rationally designed ...flexible DNA unit (F-unit), whose shape resembles a Feynman diagram. F-units were designed to self-assemble in two dimensions and to display a high DNA density of hydrophobic moieties. oxDNA simulations confirmed the planarity of the F-unit. DNA nanosheets with a thickness of a single DNA duplex layer and with large coverage (at least 30 μm × 30 μm) were assembled from the liquid phase at the solid/liquid interface, as unambiguously evidenced by atomic force microscopy imaging. Interestingly, single-layer nanodiscs formed in solution at low DNA concentrations. DNA nanosheet superstructures were further assembled at liquid/liquid interfaces, as demonstrated by the fluorescence of a double-stranded DNA intercalator. Moreover, the interfacial mechanical properties of the nanosheet superstructures were measured as a response to temperature changes, demonstrating the control of interfacial shear mechanics based on DNA nanostructure engineering. The rational design of the F-unit, along with the presented results, provide an avenue toward the controlled assembly of reconfigurable/responsive nanosheets and membranes at liquid/liquid interfaces, to be potentially used in the characterization of biomechanical processes and materials transport.
Here we present an approach to functionalize silanized single-walled carbon nanotubes (SWNTs) through copper-free click chemistry for the assembly of inorganic and biological nanohybrids. The ...nanotube functionalization route involves silanization and strain-promoted azide-alkyne cycloaddition reactions (SPACC). This was characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and Fourier transform infra-red spectroscopy. Silane-azide-functionalized SWNTs were immobilized from solution onto patterned substrates through dielectrophoresis (DEP). We demonstrate the general applicability of our strategy for the functionalization of SWNTs with metal nanoparticles (gold nanoparticles), fluorescent dyes (Alexa Fluor 647) and biomolecules (aptamers). In this regard, dopamine-binding aptamers were conjugated to the functionalized SWNTs to perform real-time detection of dopamine at different concentrations. Additionally, the chemical route is shown to selectively functionalize individual nanotubes grown on the surface of silicon substrates, contributing towards future nano electronic device applications.
The outstanding electronic properties of single wall carbon nanotubes (SWCNTs) have made them prime candidates for future nanoelectronics technologies. One of the main obstacles to the implementation ...of advanced SWCNT electronics to date is the inability to arrange them in a manner suitable for complex circuits. Directed assembly of SWCNT segments onto lithographically patterned and chemically functionalized substrates is a promising way to organize SWCNTs in topologies that are amenable to integration for advanced applications, but the placement and orientational control required have not yet been demonstrated. We have developed a technique for assembling length sorted and chirality monodisperse DNA-wrapped SWCNT segments on hydrophilic lines patterned on a passivated oxidized silicon substrate. Placement of individual SWCNT segments at predetermined locations was achieved with nanometer accuracy. Three terminal electronic devices, consisting of a single SWCNT segment placed either beneath or on top of metallic source/drain electrodes were fabricated. Devices made with semiconducting nanotubes behaved as typical p-type field effect transistors (FETs), whereas devices made with metallic nanotubes had a finite resistance with little or no gate modulation. This scalable, high resolution approach represents an important step forward toward the potential implementation of complex SWCNT devices and circuits.
Here we present a solution-based assembly method for producing molecular transport junctions employing metallic single-walled carbon nanotubes as nanoelectrodes. The molecular junction conductance of ...a series of oligophenyls was successfully measured, highlighting the potential of an all-carbon based approach for the fabrication of solution-processable single-molecule junctions for molecular electronics.
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