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The characteristics of a hydrogenated amorphous silicon (a-Si:H) detector are presented here for monitoring in space solar flares and the evolution of large energetic proton events up to hundreds of MeV. The a-Si:H presents an excellent radiation hardness and finds application in harsh radiation environments for medical purposes, for particle beam characterization and in space weather science and applications. The critical flux detection threshold for solar X rays, soft gamma rays, electrons and protons is discussed in detail., 32 pages, 13 figures, submitted to Experimental Astronomy

Objective. Microbeam radiation therapy (MRT) is an alternative emerging radiotherapy treatment modality which has demonstrated effective radioresistant tumour control while sparing surrounding healthy tissue in preclinical trials. This apparent selectivity is achieved through MRT combining ultra-high dose rates with micron-scale spatial fractionation of the delivered x-ray treatment field. Quality assurance dosimetry for MRT must therefore overcome a significant challenge, as detectors require both a high dynamic range and a high spatial resolution to perform accurately. Approach. In this work, a series of radiation hard a-Si:H diodes, with different thicknesses and carrier selective contact configurations, have been characterised for x-ray dosimetry and real-time beam monitoring applications in extremely high flux beamlines utilised for MRT at the Australian Synchrotron. Results. These devices displayed superior radiation hardness under constant high dose-rate irradiations on the order of 6000 Gy s(-1), with a variation in response of 10% over a delivered dose range of approximately 600 kGy. Dose linearity of each detector to x-rays with a peak energy of 117 keV is reported, with sensitivities ranging from (2.74 & PLUSMN; 0.02) nC/Gy to (4.96 & PLUSMN; 0.02) nC/Gy. For detectors with 0.8 & mu;m thick active a-Si:H layer, their operation in an edge-on orientation allows for the reconstruction of micron-size beam profiles (microbeams). The microbeams, with a nominal full-width-half-max of 50 & mu;m and a peak-to-peak separation of 400 & mu;m, were reconstructed with extreme accuracy. The full-width-half-max was observed as 55 & PLUSMN; 1 & mu;m. Evaluation of the peak-to-valley dose ratio and dose-rate dependence of the devices, as well as an x-ray induced charge (XBIC) map of a single pixel is also reported. Significance. These devices based on novel a-Si:H technology possess a unique combination of accurate dosimetric performance and radiation resistance, making them an ideal candidate for x-ray dosimetry in high dose-rate environments such as FLASH and MRT.

The strong, continuous progresses in gas sensors and electronic noses resulted in improved performance and enabled an increasing range of applications with large impact on modern societies, such as environmental monitoring, food quality control and diagnostics by breath analysis. Here we review this field with special attention to established and emerging approaches as well as the most recent breakthroughs, challenges and perspectives. In particular, we focus on (1) the transduction principles employed in different architectures of gas sensors, analysing their advantages and limitations; (2) the sensing layers including recent trends toward nanostructured, low-dimensional and composite materials; (3) advances in signal processing methodologies, including the recent advent of artificial neural networks. Finally, we conclude with a summary on the latest achievements and trends in terms of applications., arXiv admin comment: This version has been removed by arXiv administrators as the submitter did not have the rights to agree to the license at the time of submission

Development of highly sensitive, portable and low-cost sensors for the evaluation of ethanol content in liquid is particularly important in several process monitoring, from food to pharmaceutical industry. In this respect, here we report on the design, fabrication and performances of two simple electrical devices, namely interdigitated (ID) electrodes and complementary double split ring resonator (CDSRR), for the detection of ethanol in water though impedance and perturbation resonance methods, respectively. Both sensors resulted to be efficient for detection of low amount of ethanol in water, in particular EIS gives possibility to perform broadband evaluation of ethanol concentration in solution, and the employment of resonant cavities allows to achieve very low limit of detection of 0.2v/v%.

Recently, the hybridization of microwave-frequency cavity modes with collective spin excitations attracted large interest for the implementation of quantum computation protocols, which exploit the transfer of information among these two physical systems. Here, we investigate the interaction among the magnetization precession modes of a small YIG sphere and the MW electromagnetic modes, resonating in a tridimensional aluminum cavity. In the strong coupling regime, anti-crossing features were observed in correspondence of various magnetostatic modes, which were excited in a magnetically saturated sample. Time-resolved studies show evidence of Rabi oscillations, demonstrating coherent exchange of energy among photons and magnons modes. To facilitate the analysis of the standing spin-wave patterns, we propose here a new procedure, based on the introduction of a novel functional variable. The resulting easier identification of magnetostatic modes can be exploited to investigate, control and compare many-levels hybrid systems in cavity- and opto-magnonics research., Comment: 14 pages, 5 figures, 1 table

Polypyrrole nanowires (PPy-NWs) are synthesized by a novel templateless approach based on non-static solution-surface (NSSS) electropolymerization. The mechanism responsible for PPy-NW formation is the simultaneous oxidation of pyrrole and water, with concomitant formation of hydroxyl radicals and dioxygen nanobubbles. In particular, a localized PPy-NW deposition at the solution-air interface is enabled by solution-surface electropolymerization due to the surface excess of the monomer at the interface favored by the large surface tension of the solvent. In the proposed approach, solution-surface electropolymerization is performed in non-static conditions (NSSS), as the solution-air interface is shifted by flowing the electrolyte solution over the electrode surface. This allows a PPy-NW homogeneous deposition on whatever large area electrode to be rapidly achieved. Parameters influencing the morphology of PPy-NWs are studied, particularly focusing on flow rate, pH of the electrolyte solution, and electropolymerization time. The growth process of PPy-NWs is examined and the way of tuning their resulting morphology is discussed. Morphological investigation by scanning electron microscopy and chemical/electrochemical characterization of PPy-NWs by X-ray photoelectron spectroscopy and cyclic voltammetry, respectively, further support the proposed nanowire formation mechanism. Nanowires with diameter in the range of 40–300 nm are obtained, and the possibility of depositing differently sized nanowires with a predetermined spatial distribution on the same substrate is also demonstrated.

This work deals with the realization and characterization of integrated graphitic contacts on diamond by means of laser irradiation (graphitization), in order to obtain good quality ohmic electrodes for nuclear radiation detectors to be used in high energy physics experiments. Unlike the conventional method used for the electrode production, which requires numerous steps and very well controlled environmental conditions, this alternative technique presents many advantages: the contacts are realized in air at room temperature in a single step. In this study, the characteristics of several graphitic structures realized on a diamond surface by changing the radiation-matter interaction parameters have been evaluated in order to define the best experimental conditions to create graphitic electrodes with low resistivity. The obtained results are promising: contacts perfectly adherent, with good charge collection properties, stable and resistant to ionizing radiation

Hydrogenated amorphous silicon (a-Si:H) can be produced by plasma-enhanced chemical vapor deposition (PECVD) of SiH4 (silane) mixed with hydrogen. The resulting material shows outstanding radiation hardness properties and can be deposited on a wide variety of substrates. Devices employing a-Si:H technologies have been used to detect many different kinds of radiation, namely, minimum ionizing particles (MIPs), X-rays, neutrons, and ions, as well as low-energy protons and alphas. However, the detection of MIPs using planar a-Si:H diodes has proven difficult due to their unsatisfactory S/N ratio arising from a combination of high leakage current, high capacitance, and limited charge collection efficiency (50% at best for a 30 µm planar diode). To overcome these limitations, the 3D-SiAm collaboration proposes employing a 3D detector geometry. The use of vertical electrodes allows for a small collection distance to be maintained while preserving a large detector thickness for charge generation. The depletion voltage in this configuration can be kept below 400 V with a consequent reduction in the leakage current. In this paper, following a detailed description of the fabrication process, the results of the tests performed on the planar p-i-n structures made with ion implantation of the dopants and with carrier selective contacts are illustrated.

Ultralow-noise microwave amplification and detection play a central role in different applications, going from fundamental physics experiments to the deployment of quantum technologies. In many applications the necessity of reading multiple detectors, or cavities or qubits, calls for large bandwidth amplifiers with the lowest possible noise. Current technologies are based on High Electron Mobility Transistors and Josephson Parametric Amplifiers. Both have limitations, the former in terms of the minimum noise, the latter in terms of bandwidth. Superconducting Traveling Wave Parametric Amplifiers (TWPAs) have the potential of offering quantum limited noise and large bandwidth. These amplifiers are based on the parametric amplification of microwaves traveling along a transmission line with embedded nonlinear elements. We are developing superconducting TWPAs based both on Josephson junction arrays (Traveling Wave Josephson Parametric mplifiers) and on nonlinear kinetic inductance (Dispersion Engineered Traveling Wave Kinetic Inductance Amplifiers). Our goal is to achieve large bandwidth (in the 5 to 10 GHz range), large gain (more than 20 dB), large saturation power (more than -50 dBm), and near quantum limited noise (noise temperature less than 600 mK). Current achievements in the design and development of the high performance TWPAs are here reported and discussed, together with current limitations and possible future developments.

In this work, we report the parametric optimization of surface acoustic wave (SAW) delay lines on Lithium niobate for environmental monitoring applications. First, we show that the device performance can be improved by acting opportunely on geometrical design parameters of the interdigital transducers such as the number of finger pairs, the finger overlap length and the distance between the emitter and the receiver. Then, the best-performing configuration is employed to realize SAW sensors. As aerosol particulate matter (PM) is a major threat, we first demonstrate a capability for the detection of polystyrene particles simulating nanoparticulates/nanoplastics, and achieve a limit of detection (LOD) of 0.3 ng, beyond the present state-of-the-art. Next, the SAW sensors were used for the first time to implement diagnostic tools able to detect Grapevine leafroll-associated virus 3 (GLRaV-3), one of the most widespread viruses in wine-growing areas, outperforming electrochemical impedance sensors thanks to a five-times better LOD. These two proofs of concept demonstrate the ability of miniaturized SAW sensors for carrying out on-field monitoring campaigns and their potential to replace the presently used heavy and expensive laboratory instrumentation.

The growing interest in bio-inspired materials is driven by the need for increasingly targeted and efficient devices that also have a low ecological impact. These devices often use specially developed materials (e.g., polymers, aptamers, monoclonal antibodies) capable of carrying out the process of recognizing and capturing a specific target in a similar way to biomaterials of natural origin. In this article, we present two case studies, in which the target is a biomolecule of medical interest, in particular, {\alpha}-thrombin and cytokine IL-6. In these examples, different biomaterials are compared to establish, with a theoretical-computational procedure known as proteotronics, which of them has the greatest potential for use in a biodevice., Comment: 16 pages, 7 figures

The development of highly sensitive, portable and low-cost sensors for the evaluation of ethanol content in liquid is particularly important in several monitoring processes, from the food industry to the pharmaceutical industry. In this respect, we report the optimization of two sensing approaches based on electrical impedance spectroscopy (EIS) and complementary double split ring resonators (CDSRRs) for the detection of ethanol in water. Miniaturized EIS sensors were realized with interdigitated electrodes, and the ethanol sensing was carried out in liquid solutions without any functionalization of the electrodes. Impedance fitting analysis, with an equivalent circuit over a frequency range from 100 Hz to 1 MHz, was performed to estimate the electric parameters, which allowed us to evaluate the amount of ethanol in water solutions. On the other hand, complementary double split ring resonators (CDSRRs) were optimized by adjusting the device geometry to achieve higher quality factors while operating at a low fundamental frequency despite the small size (useful for compact electronic packaging). Both sensors were found to be efficient for the detection of low amounts of ethanol in water, even in the presence of salts. In particular, EIS sensors proved to be effective in performing a broadband evaluation of ethanol concentration and are convenient when low cost is the priority. On the other end, the employment of split ring resonators allowed us to achieve a very low limit of detection of 0.2 v/v%, and provides specific advantages in the case of known environments where they can enable fast real-time single-frequency measurements.

In this paper, by means of high-resolution photoemission, soft X-ray absorption and atomic force microscopy, we investigate, for the first time, the mechanisms of damaging, induced by neutron source, and recovering (after annealing) of p-i-n detector devices based on hydrogenated amorphous silicon (a-Si:H). This investigation will be performed by mean of high-resolution photoemission, soft X-Ray absorption and atomic force microscopy. Due to dangling bonds, the amorphous silicon is a highly defective material. However, by hydrogenation it is possible to reduce the density of the defect by several orders of magnitude, using hydrogenation and this will allow its usage in radiation detector devices. The investigation of the damage induced by exposure to high energy irradiation and its microscopic origin is fundamental since the amount of defects determine the electronic properties of the a-Si:H. The comparison of the spectroscopic results on bare and irradiated samples shows an increased degree of disorder and a strong reduction of the Si-H bonds after irradiation. After annealing we observe a partial recovering of the Si-H bonds, reducing the disorder in the Si (possibly due to the lowering of the radiation-induced dangling bonds). Moreover, effects in the uppermost coating are also observed by spectroscopies.

The removal of pollutants, such as heavy metals, aromatic compounds, dyes, pesticides and pharmaceuticals, from water is still an open challenge. Many methods have been developed and exploited for the purification of water from contaminants, including photocatalytic degradation, biological treatment, adsorption and chemical precipitation. Absorption-based techniques are still considered among the most efficient and commonly used approaches thanks to their operational simplicity. In recent years, polydopamine-coated magnetic nanoparticles have emerged for the uptake of heavy metals in water treatment, since they combine specific affinity towards pollutants and magnetic separation capacity. In this context, this work focuses on the synthesis of polydopamine (PDA)-coated Super Paramagnetic Iron Oxide Nanoparticles (PDA@SPIONs) as adsorbents for Cu2+ ions, designed to serve as functional nanostructures for the removal of Cu2+ from water by applying a magnetic field. The synthetic parameters, including the amount of SPIONs and PDA, were thoroughly investigated to define their effects on the nanostructure features and properties. Subsequently, the ability of the magnetic nanostructures to bind metal ions was assessed on Cu2+-containing solutions. A systematic investigation of the prepared functional nanostructures was carried out by means of complementary spectroscopic, morphological and magnetic techniques. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) measurements were performed in order to estimate the Cu2+ binding ability. The overall results indicate that these nanostructures hold great promise for future bioremediation applications.

Background: The loss of nigrostriatal neurons containing dopamine (DA) together with the “mitochondrial dysfunction” in midbrain represent the two main causes related to the symptoms of Parkinson’s disease (PD). Hence, the aim of this investigation is to co-administer the missing DA and the antioxidant grape seed-derived proanthocyanidins (grape seed extract, GSE) in order to increase the levels of the neurotransmitter (which is unable to cross the Blood Brain Barrier) and reducing the oxidative stress (OS) related to PD, respectively. Methods: For this purpose, we chose Solid Lipid Nanoparticles (SLN), because they have been already proven to increase DA uptake in the brain. DA-SLN adsorbing GSE (GSE/DA-SLN) were formulated and subjected to physico-chemical characterization, and their cytocompatibility and protection against OS were examined. Results: GSE was found on SLN surface and release studies evidenced the efficiency of GSE in preventing DA autoxidation. Furthermore, SLN showed high mucoadhesive strength and were found not cytotoxic to both primary Olfactory Ensheathing and neuroblastoma SH-SY5Y cells by MTT test. Co-administration of GSE/DA-SLN and the OS-inducing neurotoxin 6-hydroxydopamine (100 μM) resulted in an increase of SH-SY5Y cell viability. Conclusions: Hence, SLN formulations containing DA and GSE may constitute interesting candidates for non-invasive nose-to-brain delivery.

Aerosol particulate matter (PM) is a known risk factor for lung and liver cancer. In particular, PM under 1 μm in diameter (PM1) is very dangerous for health, affecting the respiratory system with several heavy outcomes and reaching other human districts like liver, where foreign substances are processed. Today PM1 is still difficult to be detected on-field with standard techniques and this paper reports a comparison between two sensing approaches for environmental particulate monitoring, which are suitable for miniaturization and integration into portable and low-cost devices. Specifically, transducers based on surface acoustic waves (SAW) and electrochemical impedance spectroscopy (EIS) were comparatively investigated as alternatives to more common but also expensive optical methods. Moreover, their performances were evaluated for the detection of nanoparticles of different dimensions (1 μm, 200 nm and 40 nm) to mimic different compositions of PM1 and reach a size scale which is an order of magnitude below present literature. Notably, both transduction methods were able to detect the presence of PM1 particulate. The SAW-based approach showed better performances in terms of sensitivity and detection of nanoscale particles, although the EIS strategy has a competitive sensitivity considering also its even lower cost.

The dielectric properties of YCTO bulk capacitors were investigated as a function of temperature from 25 degrees C to 150 degrees C and at microwave frequencies in comparison to a SiO2 bulk sample. The results confirm the high-k character of the YCTO ceramic, in addition to the low AC conductivity, namely epsilon' = 40.1 and sigma = 6 x 10(-8) S cm(-1) at 1 MHz, and show a weak frequency and temperature (25 degrees C-150 degrees C) dependence. A temperature coefficient value of -601 ppm degrees C-1 for the dielectric constant (TC epsilon') was estimated at 100 kHz. In the GHz regime, a comparison with bulk SiO2 confirms the higher YCTO dielectric permittivity. These results demonstrate high-k YCTO ceramic as a very promising material with high potentiality for electronic applications.

The increasing constraints in the miniaturization of modern electronic devices is driving the search for new high-k dielectric materials. Rare-earth transition metal oxides are very interesting because of the large values of dielectric constant observed in bulk samples. Here, we report on a comparison among the dielectric properties of yttrium copper titanate (YCTO) thin films and those of commonly used dielectrics such as SiO2 and MgO, grown in similar device structures. The YCTO permittivity was found to depend strongly on the oxygen pressure during deposition and can reach values even higher than those reported in bulk YCTO with good performances in terms of losses.

In the present study, a composite material consisting of polypyrrole nanowires (PPyNWs) and platinum nanoparticles (PtNPs) has been developed by an all-electrochemical approach and proved to be highly effective for electrochemical determination of dopamine (DA). PPyNWs are electropolymerized by a template-free method, and PtNPs are subsequently electrodeposited by cyclic voltammetry. Chemical characterization by X-ray photoelectron spectroscopy showed the effective PtNP immobilization on polymer nanowires discriminating at the same time Pt species deposited and revealing the occurrence of polypyrrole-PtNP interaction. The morphology of the composite material was characterized using scanning electron microscopy that showed spherical Pt nanoparticles well distributed within PPy-NW network. DA detection was performed by differential pulse voltammetry technique obtaining satisfactory performances in terms of linear range (1-77 ?M), sensitivity, reproducibility (RSD 2.7%), and detection limit (0.6 ?M). The electrocatalytic role of PtNPs in DA electroxidation process is clearly demonstrated by the comparison with PPyNWs only. Moreover, no significant response is observed in the presence of common interference as ascorbic acid and uric acid, which may coexist with DA in biological fluids, demonstrating a good selectivity toward DA. Moreover, DA was detected in human serum samples spiked obtaining a satisfactory recovery of 94%. A synergistic effect involving both PtNPs and PPyNWs is invoked for explaining the observed electrocatalytic activity.

Herein we present a straightforward approach for the use of polydopamine (PDA) in adsorption of heavy metals from aqueous solutions. This is achieved by fabricating a healthy and environmentally friendly polydimethylsiloxane (PDMS) foam with a mussel inspired PDA layer deposited on the surface. Critical adsorption parameters (pH, temperature and PDA thickness) are optimized by the application of experimental design methodology. Adsorption kinetics and isotherms are studied in detail evidencing a good fitting with Langmuir isotherm and pseudo-second-order kinetics thus suggesting the occurrence of a chemical sorption process with monolayer nature between metals and PDMS/PDA foam. Intraparticle diffusion model evidences good accessibility and high affinity of binding sites on PDA surface. Once adsorbed, metals are reduced to a lower toxic form and can be then removed by a mild acidic treatment thus being easily collected and stocked.

A computational study of the electromechanical response of micro-structure engineered two port surface acoustic wave delay lines on gallium arsenide is presented. The influence on the results of geometrical, material, and mesh parameters is also discussed. Furthermore, experimental results are provided to validate the numerical study. The device consists of two interdigital transducers composed of 40, 80, and 120 pairs of electrodes, respectively, with a pitch pidt=8μmpidt=8μm and distant didt=1502μmdidt=1502μm. In particular, a microwave burst of surface acoustic waves propagating on gallium arsenide is fully characterized including multiple transit effects. These results are of major interest for understanding the dynamical behavior of complex systems such as surface acoustic wave–based sensors or energy harvesting devices at the nano and microscale.

Sustainable growth, environmental preservation, and improvement of life quality are strategic fields of worldwide interest and cornerstones of international policies. Humanity health and prosperity are closely related to our present choices on sustainable development. The main sources of pollution concern industry, including mining, chemical companies, and refineries, wastewater treatment; and consumers themselves. In order to guide and evaluate the effects of environmental policies, diffuse monitoring campaigns and detailed (big) data analyses are needed. In this respect, the development and availability of innovative sensor platforms for field analysis and remote sensing are of crucial relevance. In this review, we provide an overview of the area, analyzing the major needs, available technologies, novel approaches, and perspectives. Among environmental pollutants that threaten the biosphere, we focus on inorganic and organic contaminants, which affect air and water quality. We describe the technologies for their assessment in the environment and then draw some conclusions and mention future perspectives opened by the integration of sensing technologies with robotics and the Internet of Things. Without the ambition to be exhaustive in such a rapidly growing field, this review is intended as a support for researchers and stakeholders looking for current, state-of-the-art, and key enabling technologies for environmental monitoring.

Energy efficient, low-cost, user-friendly, and green methods for the removal of toxic phenolic compounds from aqueous solution are necessary for waste treatment in industrial applications. Herein we present an interesting approach for the utilization of oxidized carbon nanotubes (CNTs) in the removal of phenolic compounds from aqueous solution. Dried pristine CNTs were stably incorporated in a solid porous support of polydimethylsiloxane (PDMS) facilitating the handling during both oxidation process of the nanomaterial and uptake of phenolic compounds, and enabling their safe disposal, avoiding expensive post-treatment processes. The adsorption studies indicated that the materials can efficiently remove phenolic compounds from water with different affinities towards different phenolic compounds. Furthermore, the adsorption kinetics and isotherms were studied in detail. The experimental data of adsorption fitted well with Langmuir and Freundlich isotherms, and pseudo-second-order kinetics, and the results indicated that the adsorption process was controlled by a two-step intraparticle diffusion model. The incorporation of CNTs in polymeric matrices did not affect their functionality in phenol uptake. The material was also successfully used for the removal of phenolic compounds from agricultural waste, suggesting its possible application in the treatment of wastewater. Moreover, the surface of the material could be regenerated, decreasing treatment costs.

Colloidal lithography is an innovative fabrication technique employing spherical, nanoscale crystals as a lithographic mask for the low cost realization of nanoscale patterning. The features of the resulting nanostructures are related to the particle size, deposition conditions and interactions involved. In this work, we studied the absorption of polystyrene spheres onto a substrate and discuss the effect of particle–substrate and particle–particle interactions on their organization. Depending on the nature and the strength of the interactions acting in the colloidal film formation, two different strategies were developed in order to control the number of particles on the surface and the interparticle distance, namely changing the salt concentration and absorption time in the particle solution. These approaches enabled the realization of large area (≈cm2) patterning of nanoscale holes (nanoholes) and nanoscale disks (nanodisks) of different sizes and materials.

Functional, flexible, and integrated lab-on-chips, based on elastic membranes, are capable of fine response to external stimuli, so to pave the way for many applications as multiplexed sensors for a wide range of chemical, physical and biomedical processes. Here, we report on the use of elastic thin membranes (TMs), integrated with a reaction chamber, to fabricate a membrane-based pressure sensor (MePS) for reaction monitoring. In particular, the TM becomes the key-element in the design of a highly sensitive MePS capable to monitor gaseous species production in dynamic and temporally fast processes with high resolution and reproducibility. Indeed, we demonstrate the use of a functional MePS integrating a 2 pm thick polydimethylsiloxane TM by monitoring the dioxygen evolution resulting from catalytic hydrogen peroxide dismutation. The operation of the membrane, explained using a diffusion-dominated model, is demonstrated on two similar catalytic systems with catalase-like activity, assembled into polyelectrolyte multilayers capsules. The MePS, tested in a range between 2 and 50 Pa, allows detecting a dioxygen variation of the mu mol L-1 s(-1) order. Due to their structural features, flexibility of integration, and biocompatibility, the MePSs are amenable of future development within advanced lab-on-chips.

We report a design of photocathode, which combines the good photoemissive properties of lead (Pb) and the advantages of superconducting performance of niobium (Nb) when installed into a superconducting radio-frequency gun. The new configuration is obtained by a coating of Nb thin film grown on a disk of Pb via pulsed laser deposition. The central emitting area of Pb is masked by a shield to avoid the Nb deposition. The nanomechanical properties of the Nb film, obtained through nanoindentation measurements, reveal a hardness of 2.8±0.3 GPa, while the study of the electrical resistivity of the film shows the appearance of the superconducting transitions at 9.3 K and 7.3 K for Nb and Pb, respectively, very close to the bulk material values. Additionally, morphological, structural and contamination studies of Nb thin film expose a very low droplet density on the substrate surface, a small polycrystalline orientation of the films and a low contamination level. These results, together with the acceptable Pb quantum efficiency of 2×10−5 found at 266 nm, demonstrate the potentiality of the new concept photocathode. Funding agencies: Italian National Institute of Nuclear Physics (INFN); Italian MIUR through the Project FIRB Futuro in Ricerca [RBFR12NK5K]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

Mixed iron-manganese oxide nanoparticles, synthesized by a simple procedure, were used to remove nickel ion from aqueous solutions. Nanostructures, prepared by using different weight percents of manganese, were characterized by transmission electron microscopy, selected area diffraction, X-ray diffraction, Raman spectroscopy, and vibrating sample magnetometry. Adsorption/desorption isotherm curves demonstrated that manganese inclusions enhance the specific surface area three times and the pores volume ten times. This feature was crucial to decontaminate both aqueous samples and food extracts from nickel ion. Efficient removal of Ni2+ was highlighted by the well-known dimethylglyoxime test and by ICP-MS analysis and the possibility of regenerating the nanostructure was obtained by a washing treatment in disodium ethylenediaminetetraacetate solution.

The surface of a detector grade CVD polycrystalline diamond sample (5 × 5 × 0.05 mm3) was irradiated by an ArF excimer laser (? = 193 nm, ? = 20 ns) to produce graphitic conductive layers. In particular, two sets of four parallel graphitic strip-like contacts, with 1 mm pitch, were created along the whole sample on the top and on the rear surfaces of the sample respectively. The two series of stripes lie normally to each other. Such a grid allows to obtain a segmented all-carbon device capable of giving bi-dimensional information on particle detection processes in nuclear applications. Afterwards, an extensive characterization of the samples was performed: SEM and micro-Raman investigations to study the morphological and structural evolution of the irradiated areas, EDS measurements to individuate any absorption phenomena from environment associated to laser treatment, and nanoindentation mapping to understand how the hard-soft transformation occurred depending on the locally transferred energy. Finally, current-voltage analyses were carried out checking the ohmic behavior of the diamond-graphite contact. By comparing the results of the different characterization analyses, a strong periodicity of the modified surface properties was found, confirming the reliability and reproducibility of the laser-induced graphitization process. The results demonstrate that the laser-writing technique is a good and fast solution to produce graphitic contacts on diamond surface and therefore represents a promising way to fabricate segmented all-carbon devices. © 2016 Elsevier B.V.

In this work different fabrication methods based on low cost lithographic techniques have been developed in order to create planar distributions of plasmonic nanostructures with tailored optical functionalities. In order to achieve sharp Localized Surface Plasmon Resonance (LSPR) resonances in the visible and IR range, the geometry of the fabricated nanostructures have been optimized through numerical modelling. The optical properties and the sensing capabilities of different metal nanostructures have been investigated, exploring several key parameters for sensitivity enhancement of traditional LSPR biosensors.

In this work, we demonstrate the excitation of surface acoustic waves (SAW) harmonics up to GHz regime in photolitographed devices fabricated on gallium arsenide (GaAs) by acting on the IDT metallization ratio among the finger width and pitch. Specifically, we observed up to the 13th harmonic, which corresponds to a frequency of about 1.7 GHz. Moreover, we employed time-resolved spectroscopy for isolating the shape of the SAW bandpass-filter response (for each harmonic) eliminating the interference between acoustic and electromagnetic waves. Notably, the extracted SAW spectra are characterized by a bandwidth which remains constant for the different harmonic modes, unlike the case of traditional SAW filters (having a 0.5 metallization ratio) where the pass band Delta f = f(0)/n(p) np increases with the working frequency. These results are relevant for applications where high frequencies and multiple harmonics excitation are desirable, or where quantitative measurements of the direct SAW signal are required.

Authors aimed to provide a magnetic responsiveness to bone-mimicking nano-hydroxyapatite (n-HA). For this purpose, dextran-grafted iron oxide nanoarchitectures (DM) were synthesized by a green-friendly and scalable alkaline co-precipitation method at room temperature and used to functionalize n-HA crystals. Different amounts of DM hybrid structures were added into the nanocomposites (DM/n-HA 1:1, 2:1 and 3:1weight ratio) which were investigated through extensive physicochemical (XRD, ICP, TGA and Zeta-potential), microstructural (TEM and DLS), magnetic (VSM) and biological analyses (MTT proliferation assay). X-ray diffraction patterns have confirmed the n-HA formation in the presence of DM as a co-reagent. Furthermore, the addition of DM during the synthesis does not affect the primary crystallite domains of DM/n-HA nanocomposites. DM/n-HAs have shown a rising of the magnetic moment values by increasing DM content up to 2:1 ratio. However, the magnetic moment value recorded in the DM/n-HA 3:1 do not further increase showing a saturation behaviour. The cytocompatibility of the DM/n-HA was evaluated with respect to the MG63 osteoblast-like cell line. Proliferation assays revealed that viability, carried out in the absence of external magnetic field, was not affected by the amount of DM employed. Interestingly, assays also suggested that the DM/n-HA nanocomposites exhibit a possible shielding effect with respect to the anti-proliferative activity induced by the DM particles alone.

In the last years there has been an increase of interest in diamond devices because of the promising applications in different field, such as high-energy physics, radiotherapy and biochemical applications. In particular, a new frontier is represented by the realization of full-carbon detectors characterized by graphite electrodes, which give to the devices considerable advantages like high radiation hardness, perfect mechanical adhesion and good charge collection properties. In this paper the manufacturing of full-carbon devices and their detection performances are illustrated and compared to a reference diamond detector characterized by traditional electrodes.

Lower genital tract infections caused by both sexually and not-sexually transmitted pathogens in women are a key public health priority worldwide, especially in developing countries. Since standard analyses are time-consuming, appropriate therapeutic intervention is often neglected or delayed. Lab-on-chips and biosensors open new perspectives and offer innovative tools to simplify the diagnosis by medical staff, especially in countries with inadequate resources. Here we report a biosensing platform based on Electrochemical Impedance Spectroscopy (EIS) that allows multiplexed detection of Candida albicans, Streptococcus agalactiae and Chlamydia trachomatis with a single biochip, enabling a quick screening thanks to the presence of different immobilized antibodies, each specific for one of the different target pathogens.

The structural, dielectric, and ferroelectric characterization of multiphase Bi‐Fe‐O prepared with an excess of Bi up to 20% is reported. It is found that the dominant phase in all samples is the BiFeO3 perovskite in addition to an increasing amount of the Bi‐rich sillenite phases (Bi12.5Fe0.5O19.48/Bi25FeO39) with the Bi excess content. At room temperature, the multiphase Bi‐Fe‐O results in advanced electrical properties, with higher dielectric constant (161 at 1 MHz) and low losses (tanδ = 0.032 at 1 MHz). The ferroelectric character of multiphase ceramics is confirmed by PUND measurements, which shows increased polarization values and coercive field with respect to the single phase ceramics.

In the last years, many studies have been performed on metal nanoparticles because of their possible applications as chemical and biological sensors [1]. Particularly, new design and fabrication strategy of plasmonic transductors have been proposed in order to enhance their sensing performances and reproducibility. Unfortunately, the most used fabrication methods for metallic nanostructured systems, such as EBL and FIB, are less accessible choices for scientists and industrial applications due to their critical drawbacks, like low speed and high-cost.

Celiac disease (CD) is one of the most common digestive disorders caused by an abnormal immune reaction to gluten. So far there are no available therapies, the only solution is a strict gluten-free diet, which however could be very challenging as gluten can be hidden in many food products. Furthermore an additional problem is related to cross-contamination of nominal gluten-free foods with gluten-based ones during manufacturing. Here we propose a lab on chip platform as a powerful tool to help food manufacturers to evaluate the real amount of gluten in their products by an accurate in-situ control of the production chain and maybe to specify the real gluten content in packages labeling. Our portable gliadin-immunochips, based on an electrochemical impedance spectroscopy transduction method, were first calibrated and then validated for both liquid and solid food matrixes by analyzing different beers and flours. The high specificity of our assay was also demonstrated by performing control experiments on rice and potatoes flours containing prolamin-like proteins. We achieved limit of quantification of 0.5 ppm for gliadin that is 20 times lower than the worldwide limit established for gluten-free food while the method of analysis is faster and cheaper than currently employed ELISA-based methods. Moreover our results on food samples were validated through a mass spectrometry standard analysis. (C) 2015 Elsevier B.V. All rights reserved.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal cancers in Europe and the United States. It has a very low 5 years-survival rate and its diagnosis is often late and imprecise due to the lack of specificity of currently used markers for PDAC. As previously demonstrated PDAC patients’ sera may contain autoantibodies towards phosphorylated a-enolase (ENOA), which in combination with other standard markers can increase specificity in diagnosis of PDAC. In this context we realized a microfluidic platform with integrated EIS biosensors. We achieved a specific antibodies detection by immobilizing onto electrodes peptides corresponding to a portion of ENOA. Phosphorylation of peptides was found to influence the recognition of antibodies in PDAC patients’ sera detected by the developed biochip thus validating the EIS technique as a strong tool for quick, cost-saving and label-free analysis of serum samples. Biochip results are in agreement with those from traditional techniques, such as ELISA and western blot, but measurements are much more sensitive and specific, increasing the possibility of PDAC diagnosis. In addition this approach is faster and more reproducible compared to traditional techniques making the developed biochips ideal for a quick, cost-saving and label-free analysis of serum samples.

Nearly amorphous high-k yttrium copper titanate thin films deposited by laser ablation were investigated in both metal-oxide-semiconductor (MOS) and metal-insulator-metal (MIM) junctions in order to assess the potentialities of this material as a gate oxide. The trend of dielectric parameters with film deposition shows a wide tunability for the dielectric constant and AC conductivity, with a remarkably high dielectric constant value of up to 95 for the thick films and conductivity as low as 6 x 10(-10) S cm(-1) for the thin films deposited at high oxygen pressure. The AC conductivity analysis points out a decrease in the conductivity, indicating the formation of a blocking interface layer, probably due to partial oxidation of the thin films during cool-down in an oxygen atmosphere. Topography and surface potential characterizations highlight differences in the thin film microstructure as a function of the deposition conditions; these differences seem to affect their electrical properties.

Here an EIS (electrochemical impedance spectroscopy) biochip to detect cell migration is demonstrated. This biochip has been inspired by a traditional transwell assay/modified Boyden chamber and consists of two compartments separated by a porous membrane. This structure (PDMS-based) is aligned to EIS sensors. Cells are seeded in the upper chamber through microfluidic channels. During migration cells go through the pores of the membrane and get in touch with the electrodes that detect migrated cells. The performance of our cell-chip was tested by investigating the migratory ability of hepatocellular carcinoma (HCC) cells as a function of microenvironment. For this purpose we challenged HCC cells to migrate on different extra-cellular matrix (ECM) components including laminin 1, collagen IV and laminin 5. The results reveal that our cell chip provides reliable results that consistently overlap with those obtained with traditional standardized Boyden chambers. Thus, we demonstrate a new, easy tool to study cell migration and to perform automatic assays. This approach is easier and faster than traditional transwell assays and can be suitable for high-throughput studies in drug discovery applications.