A jellified alginate based capsule serves as biocompatible and biodegradable electrolyte system to gate an organic field-effect transistor fabricated on a flexible substrate. Such a system allows operating thiophene based polymer transistors below 0.5 V through an electrical double layer formed across an ion-permeable polymeric electrolyte. Moreover, biological macro-molecules such as glucose-oxidase and streptavidin can enter into the gating capsules that serve also as delivery system. An enzymatic bio-reaction is shown to take place in the capsule and preliminary results on the measurement of the electronic responses promise for low-cost, low-power, flexible electronic bio-sensing applications using capsule-gated organic field-effect transistors

We report the information that in the days of the radio anomaly presented in the paper Biagi et al. (2009) an interruption of the broadcasting from the transmitter (RMC, France) happened. It remains unclear if the action resulted in a complete power off of the system, or in a reduction in the radiated power, and if this has affected France only, or every direction. Should a complete power off have occurred, the proposed pre-seismic efocusing is inexistent. Our doubts on this action are reported.

In a previous study, an apparatus generating 1.8 GHz electromagnetic radiation for “in vivo” biomedical study was designed and implemented. The apparatus consisted of a reverberation chamber and it reproduced a habitat similar to the usual one for the laboratory animals. Plexiglas boxes with 300 cc physiological liquid were utilized as simple phantoms. For the measurements a small Electric Field Probe was used. The maximum SAR (Specific Absorption Rate) and average Power Efficiency Pe (SAR/input power) values obtained were quite low (“in vivo experiments”) and this was the drawback of the apparatus. In the present work, different modifications introduced in order to increase SAR and Power Efficiency are presented. In the new configuration, the dosimetry for the previous phantoms and for oil-in-gelatine phantoms was investigated and quite satisfactory SAR and Power Efficiency values were obtained, overcoming the previous drawback. In the first case the sensor was waterproofed, as in the previous study; in the other case a Plexiglas box with inside a tight shaped allocation for the measurement probe was realized. These measurement technologies could be applied to other media used for the phantoms.

We report the information that in the days of the radio anomaly presented in the paper Biagi et al. (2009) an interruption of the broadcasting from the transmitter (RMC, France) happened. It remains unclear if the action resulted in a complete power off of the system, or in a reduction in the radiated power, and if this has affected France only, or every direction. Should a complete power off have occurred, the proposed pre-seismic defocusing is inexistent. Our doubts on this action are reported.

A new class of radiation detectors based on carbon nanostructures as the active photosensitive element has been recently developed. In this scenario the optimization of the device, both in dark and on light irradiation, is a crucial point. Here, we report on electrical measurements performed in dark conditions on carbon nanofibers and nanotubes deposited on silicon substrates. Our experimental results were interpreted in terms of a multistep tunneling process occurring at the carbon nanostructures/silicon interface. (C) 2010 Elsevier B.V. All rights reserved.

Hysteresis behaviour of the current-voltage characteristics collected on spin coated synthetic eumelanin layer embedded in the Au/eumelanin/ITO/glass structure is shown. The effect has been observed under dark both in air and vacuum environment and its magnitude has been found related to the eumelanin hydration state. Moreover, in vacuum and under white light illumination, enhancement of the hysteresis loop area respect to those collected under dark has been observed. Space charge storage and charge trapping/detrapping as possible mechanisms responsible of the observed current-voltage behaviour are discussed. Preliminary experimental results have evidenced the possible integration of eumelanin layers in electro-optical charge storage based memory devices. (C) 2010 Elsevier B.V. All rights reserved.

Hysteresis behaviour of the current–voltage characteristics collected on spin coated synthetic eumelanin layer embedded in the Au/eumelanin/ITO/glass structure is shown. The effect has been observed under dark both in air and vacuum environment and its magnitude has been found related to the eumelanin hydration state. Moreover, in vacuum and under white light illumination, enhancement of the hysteresis loop area respect to those collected under dark has been observed. Space charge storage and charge trapping/detrapping as possible mechanisms responsible of the observed current–voltage behaviour are discussed. Preliminary experimental results have evidenced the possible integration of eumelanin layers in electro-optical charge storage based memory devices.

Aims: Until now, studies related to the morphometric and morphological variations produced on peripheral blood leukocytes from healthy donors by exposure to 1.8 GHz electromagnetic radiation (EMR) yielded controversial results. The aim of this research work is to increase the statistics regarding the above mentioned variations. Methodology: By using a reverberation chamber, which provides a controlled EMR intensity, 108 samples of human leukocytes from healthy donors were exposed to EMR of different intensities (12±4 V/m, 22±6 V/m, 42±9 V/m and 78±10 V/m) for times ranging from 5 min to 24 h. Sham exposed blood samples of the same donors were considered as controls. Using a computerized morphometric method, microscopic observations of the area size occupied by each cell were conducted; in each case the dimensional measurements were carried out on three different samples (from different donors). Besides, morphological observations were conducted staining smeared blood samples with May-Grünwald-Giemsa. Results: Exposed and sham exposed leukocytes average size was compared using the Statistical GraphPad Prism 5.0 software. In 18% out of 108 cases examined, no effects dependent on EMR have been revealed. On the contrary, statistically significant variations in area of exposed leukocytes in comparison to non exposed cells were observed in 82% out of 108 cases examined. In 68% out of 108 cases an increase in leukocyte areas was demonstrated along with morphological variations of cells; in 14% out of 108 the cases, a decrease in leukocyte areas was observed. Conclusions: Even though this study needs a functional evaluation of leukocytes exposed to EMR, our results suggest that 1.8 GHz EMR is able to produce increase in the leukocyte areas as well as morphological alterations.

Synthetic melanin based metal-insulator-semiconductor devices are fabricated for the first time thanks to silicon surface wettability modification by using dielectric barrier discharge plasma. Ambipolar charge trapping in air and ion drift mechanisms under vacuum are identified by capacitance-voltage hysteresis loops. These results aim to foresee the possible integration of synthetic melanin layers as a novel capacitor in organic polymer based devices.

The electrical transport across a biomimetic interface made up of spin coated melanin layers on nanotextured silicon surfaces with different texturing features and wetting properties is discussed. Nanotexturing allows, under certain conditions, the melanin better anchoring on a hydrophobic silicon surface, overcoming the hydrophilic melanin-hydrophobic silicon interface criticism. The feature of the electrical signal transduction across such a structure was studied by impedance spectroscopy and found to be influenced by the nano-texturing chemistry and surface morphology. The effects of a voltage pulse, as external stimulus modifying the electrical transport mechanisms and retention of the subsequently achieved carrier transport conditions have been elucidated. The results let to foresee a possible exploiting of this circuital element for bio and environmental molecules sensing.

A totally innovative electrolyte-gated field effect transistor, embedding a phospholipid film at the interface between the organic semiconductor and the gating solution, is described. The electronic properties of OFETs including a phospholipid film are studied in both pure water and in an electrolyte solution and compared to those of an OFET with the organic semiconductor directly in contact with the gating solution. In addition, to investigate the role of the lipid layers in the charge polarization process and quantify the field-effect mobility, impedance spectroscopy was employed. The results indicate that the integration of the biological film minimizes the penetration of ions into the organic semiconductor thus leading to a capacitive operational mode as opposed to an electrochemical one. The OFETs operate at low voltages with a field-effect mobility in the 10^-3 cm^2 V^-1 s^-1 range and an on/off current ratio of 10^3. This achievement opens perspectives to the development of FET biosensors potentially capable to operate in direct contact with physiological fluids.

The integration of biopolymers into hybrid electronics is one of the up to date issues in view of the achievement of fully bio-compatible devices. Among ‘hot topics’ in bio-polymer research, synthetic melanin or, briefly, “melanin”, has been recently recognized as a quite intriguing macromolecule thanks to its multifunctional optoelectronic properties. To date, melanin transport properties have been mainly enlightened on pellets, while optical absorption and conductivity properties have been investigated on melanin layers deposited on quartz and indium tin oxide/glass. The unavailability of suitable procedures to improve or promote adequate self assembling of melanin layer deposition onto substrate of interest in organic and solid state electronics (hybrid) like silicon substrates, prevent interesting studies on such structures. The reason stems basically on the difference between the hydrophilic nature of the melanin and the hydrophobic one of the supports (mostly of silicon). However, our group solved this issue and was able to tailor a melanin based metal/insulator/metal and metal/insulator/silicon structures, where synthetic melanin was embedded as the insulating part. This allowed to disclose interesting features related to data storage capabilities of melanin layers deposited on indium tin oxide/glass and silicon never investigated so far. In this work we show an overview on our recent mentioned results, and particular attention is paid on structures on silicon substrates. The use of pSi and nSi substrates and measurements under different environment conditions has enabled to gain insight into ambipolar electrical transport mechanisms, still unexplored. These results constitute a first important basic insight into melanin-based bio inspired structures and represent a significant step towards their integration in several kinds of hybrid organic polymer-based devices.

This work enlighten on the modification of the electrical and optoelectronic properties at metal/silicon interface, where the silicon surface is nanostructured by single step mask-less CF4 plasma in reactive ion etching mode. The electrical transport across metal/nanotextured silicon/silicon structure has been correlated with morphological variations of surface topological features and chemistry. The results evidence that such nanostructures enhance the photovoltaic behavior and affect electrical and optoelectronic transport to a different extent, depending not only on surface texturing but also on surface chemistry. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4710989]

In the last years disturbances in VLF/LF radio signals related to seismic activity have been presented. The radio data were collected by receivers located on the ground or on satellites. The ground-based research implies systematic data collection by a network of receivers. Since 2000 the "Pacific VLF network", conducted by Japanese researchers, has been in operation. During 2008 a radio receiver was developed by the Italian factory Elettronika (Palo del Colle, Bari). The receiver is equipment working in VLF and LF bands. It can monitor 10 frequencies distributed in these bands and, for each of them, it saves the power level. At the beginning of 2009, five receivers were made for the realization of the "European VLF/LF Network"; two were planned for Italy and one for Greece, Turkey and Romania, respectively. In 2010 the network was enlarged to include a new receiver installed in Portugal. In this work, first the receiver and its setting up in the different places are described. Then, several disturbances in the radio signals related to the transmitters, receivers, meteorological/geomagnetic conditions are presented and described.

Organic thin film transistor (OTFT) technology can be implemented to develop cost-effective and label-free bio-affinity sensor chips, having a field-effect transport directly coupled to a bio-sensing process, useful to high-throughput testing and point-of-care applications. Biological recognition elements such as antibodies or other proteins can be integrated in OTFT devices to confer specificity. In this study the use of lipid bilayers as support for biomolecules immobilization is investigated. Preliminary results in terms of electrical resistance and capacitance of the lipid bilayers are presented.

In 2008, a radio receiver that works in very low frequency (VLF; 20-60 kHz) and LF (150-300 kHz) bands was developed by an Italian factory. The receiver can monitor 10 frequencies distributed in these bands, with the measurement for each of them of the electric field intensity. Since 2009, to date, six of these radio receivers have been installed throughout Europe to establish a 'European VLF/LF Network'. At present, two of these are into operation in Italy, and the remaining four are located in Greece, Turkey, Portugal and Romania. For the present study, the LF radio data collected over about two years were analysed. At first, the day-time data and the night-time data were separated for each radio signal. Taking into account that the LF signals are characterized by ground-wave and sky-wave propagation modes, the day-time data are related to the ground wave and the night-time data to the sky wave. In this framework, the effects of solar activity and storm activity were defined in the different trends. Then, the earthquakes with M ≥5.0 that occurred over the same period were selected, as those located in a 300-km radius around each receiver/transmitter and within the 5th Fresnel zone related to each transmitter-receiver path. Where possible, the wavelet analysis was applied on the time series of the radio signal intensity, and some anomalies related to previous earthquakes were revealed. Except for some doubt in one case, success appears to have been obtained in all of the cases related to the 300 km circles in for the ground waves and the sky waves. For the Fresnel cases, success in two cases and one failure were seen in analysing the sky waves. The failure occurred in August/September, and might be related to the disturbed conditions of the ionosphere in summer. © 2012 by the Istituto Nazionale di Geofisica e Vulcanologia. All rights reserved