We present the main steps of FOS (based on LPG and FBG) installation in the CERN-ATLAS experiment for temperature and humidity measurements, from laboratory calibrations and data acquisition chain development, to their installation and operation.

Il contributo presenta i sensori utilizzabili per sistemi di monitoraggio e allarme per le colate detritiche e discute i problemi della loro implementazione

Distributed optical fiber sensing is a unique technology that offers unprecedented advantages and performance, especially in those experimental fields where requirements such as high spatial resolution, the large spatial extension of the monitored area, and the harshness of the environment limit the applicability of standard sensors. In this paper, we focus on one of the scattering mechanisms, which take place in fibers, upon which distributed sensing may rely, i.e., the Rayleigh scattering. One of the main advantages of Rayleigh scattering is its higher efficiency, which leads to higher SNR in the measurement; this enables measurements on long ranges, higher spatial resolution, and, most importantly, relatively high measurement rates. The first part of the paper describes a comprehensive theoretical model of Rayleigh scattering, accounting for both multimode propagation and double scattering. The second part reviews the main application of this class of sensors.

Three new fluorescent molecular rotors were synthesized with the aim of using them as sensors to dose thymidine phosphorylase, one of the target enzymes of 5-fluorouracil, a potent chemotherapic drug largely used in the treatment of many solid tumors, that acts by hindering the metabolism of pyrimidines. 5-Fluorouracil has a very narrow therapeutic window, in fact, its optimal dosage is strictly related to the level of its target enzymes that vary significantly among patients, and it would be of the utmost importance to have an easy and fast method to detect and quantify them. The three molecular rotors developed as TP sensors differ in the length of the alkylic spacer joining the ligand unit, a thymine moiety, and the fluorescent molecular rotor, a [4-(1-dimethylamino)phenyl]-pyridinium bromide. Their ability to trigger an optical signal upon the interaction with thymidine phosphorylase was investigated by fluorescent measurements.

We consider refractive index sensing with optical bounds states in the continuum (BICs) in dielectric gratings. Applying a perturbative approach we derived the differential sensitivity and the figure of merit of a sensor operating in the spectral vicinity of a BIC. Optimisation design approach for engineering an effective sensor is proposed. An analytic formula for the maximal sensitivity with an optical BIC is derived. The results are supplied with straightforward numerical simulations. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

In this work, we investigate the evanescent field sensing mechanism provided by an all-dielectric metasurface supporting bound states in the continuum (BICs). The metasurface is based on a transparent photonic crystal with subwavelength thickness. The BIC electromagnetic field is localized along the direction normal to the photonic crystal nanoscale-thin slab (PhCS) because of a topology-induced confinement, exponentially decaying in the material to detect. On the other hand, it is totally delocalized in the PhCS plane, which favors versatile and multiplexing sensing schemes. Liquids with different refractive indices, ranging from 1.33 to 1.45, are infiltrated in a microfluidic chamber bonded to the sensing dielectric metasurface. We observe an experimental exponential sensitivity leading to differential values as large as 226 nm/RIU with excellent FOM. This behavior is explained in terms of the physical superposition of the field with the material under investigation and supported by a thorough numerical analysis. The mechanism is then translated to the case of molecular adsorption where a suitable theoretical engineering of the optical structure points out potential sensitivities as large as 4000 nm/RIU. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Multi-walled carbon nanotubes (CNTs) decorated with zinc oxide nanoparticles (ZnO NPs) were prepared in isopropanol solution by a simple, room-temperature process and characterized from structural, morphological, electronic, and optical points of view. A strong interaction between ZnO and CNTs is fully confirmed by all the characterization techniques. ZnO-CNTs nanocomposites, with different weight ratios, were deposited as a dense layer between two electrodes, in order to investigate the electrical behaviour. In particular, the electrical response of the nanocomposite layers to UV light irradiation was recorded for a fixed voltage: As the device is exposed to the UV lamp, a sharp current drop takes place and then an increase is observed as the irradiation is stopped. The effect can be explained by adsorption and desorption phenomena taking place on the ZnO nanoparticle surface under irradiation and by charge transfer between ZnO and CNTs, thanks to the strong interaction between the two nanomaterials. The nanocomposite material shows good sensitivity and fast response to UV irradiation. Room temperature and low-cost processes used for the device preparation combined with room temperature and low voltage operational conditions make this methodology very promising for large scale UV detectors applications.

The work presents a design of electronic printed circuit board for a prototype of a Industry 4.0 ready sensor aimed at smart spindle technology. It composes of both electronic cirtuit schematic as well as the layout of the physicial PCB.

A preliminary assessment of properties of the commercial product Chemiplus 2DS HB (BI-QEM Specialties SpA) is proposed. Cyclic voltammetry of this oligomer containing sulfate/sulfone groups shows a single oxidative peak at +0.866 V vs. Ag/AgCl, and its passivating process on Pt electrode suggests the formation of a non-conductive layer. Electrode modification was achieved by exploiting the constant potential amperometry setting potential at +0.900 V vs. Ag/AgCl. A substantial change in the oxidative currents from electroactive species H2O2 and ascorbic acid (AA) were observed on Pt/Chemiplus 2DS HB sensors compared to unmodified Pt. Furthermore, the influence of different storage conditions on modified sensors was examined. A storage solution containing AA concentration from 0.1 until 10 mM maintained effective AA rejection of Pt/Chemiplus 2DS HB after 7 days from construction; H2O2 oxidation capability was also retained. Sulfone and sulfonate groups of Chemiplus 2DS HB are likely responsible for the dimensionality of the film and the electrostatic interaction leading to a self-blocking/self-rejection of AA. The way Pt/Chemiplus can reveal the AA presence depends on the maintaining of AA rejection, and this peculiarity can distinguish it from other sensors or biosensors.

In an attempt to produce a SERS-active and low cost sensor for label free detection of trace amounts and small volumes of biomolecule samples, silver nanowires with high aspect ratio were implemented in a flow-through self assembly process on hydrophobic PTFE membrane. This bottom up assembly was followed by spot arrays design and fabrication through laser patterning of the silver nanostructured surface, leading to the formation of circular spots of defined size aimed at both concentrating microliter volumes of aqueous solution droplets and enhancing the Raman signal of micromolar amounts of biomolecules. The spot arrays so produced were efficiently tested as SERS sensors via direct detection, i.e. by direct measurement of the analyte molecular Raman fingerprint, with several proteins and biomarkers of neurodegenerative diseases and they showed excellent reproducibility and sensitivity. The specificity of the detection system is intrinsic in the Raman spectroscopic signal, which enables a structural characterization of the biomolecules while a rapid and effective detection is perfomed. The silver spot arrays can also represent a versatile label free SERS platform for indirect biomolecular detection, thanks to the simple and easy functionalization of the silver spots by thiolated small molecules and receptors.

Organic electrochemical transistors (OECTs) operated in the faradic regime were shown as outperforming transducers of bioelectric signals in vitro and in vivo. Fabrication by additive manufacturing techniques fosters OECTs as ideal candidates for point-of-care applications, as well as imposes limitations on the choice of materials and their processing conditions. Here, we address the question of how the response of fully printed OECTs depends on gate electrode material. Toward this end, we investigate the redox processes underlying the operation of OECTs under faradic regime, to show OECTs with carbon gate (C-gate) that exhibit no current modulation gate voltages <1.2 V. This is a hallmark that no interference with the faradic operation of the device enabled by redox processes occurs when operating C-gate OECTs in the low-voltage range as label-free biosensors for the detection of electroactive (bio)molecules. To tune the faradic response of the device, we electrodeposited Au on the carbon gate (Au-C-gate), obtaining a device that operates at lower gate voltage values than C-gate OECT. The presence of gold on the gate allowed further modification of the electrical performances by functionalization of the Au-C-gate with different self-assembled monolayers by fast potential-pulse-assisted method. Moreover, we show that the presence in the electrolyte solution of an external redox probe can be used to drive the faradic response of both C-and Au-C-gate OECTs, impacting on the gate potential window that yields effective drain current modulation. The results presented here suggest possible new strategies for controlling the faradic operation regime of OECTs sensors by chemical modification of the gate surface.

The realization of an efficient optical sensor based on a photonic crystal metasurface supporting bound states in the continuum is reported. Liquids with different refractive indices, ranging from 1.4000 to 1.4480, are infiltrated in a microfluidic chamber bonded to the sensing dielectric metasurface. A bulk liquid sensitivity of 178 nm/RIU is achieved, while a Q-factor of about 2000 gives a sensor figure of merit up to 445 in air at both visible and infrared excitations. Furthermore, the detection of ultralow-molecular-weight (186 Da) molecules is demonstrated with a record resonance shift of 6 nm per less than a 1 nm thick single molecular layer. The system exploits a normal-to-the-surface optical launching scheme, with excellent interrogation stability and demonstrates alignment-free performances, overcoming the limits of standard photonic crystals and plasmonic resonant configurations. (C) 2018 Chinese Laser Press

We demonstrate that conductometric gas sensing at room temperature with SnO2 nanowires (NWs) is enhanced by visible and supraband gap UV irradiation when and only when the metal oxide NWs are decorated with Ag nanoparticles (NPs) (diameter < 20 nm); no enhancement is observed for the bare SnO2 case. We combine the spectroscopic techniques with conductometric gas sensing to study the wavelength dependency of the sensors' response, showing a strict correlation between the Ag-loaded SnO2 optical absorption and its gas response as a function of irradiation wavelength. Our results lead to the hypothesis that the enhanced gas response under UV vis light is the effect of plasmonic hot electrons populating the Ag NPs surface. Finally, we discuss the chemiresistive properties of Ag-loaded SnO2 sensor in parallel with the theory of plasmon-driven catalysis, to propose an interpretative framework that is coherent with the established paradigma of these two separated fields of study.

This paper discusses the design and implementation of an experimental test bed for radio frequency (RF) sensor wake-up. The test bed relies on an unmanned aerial vehicle (UAV) that selectively feeds a deployed sensor in a wireless sensor network for wake-up purposes. The telemetry signal of the UAV is harvested by a rectenna integrated within a sensor. As a result, the output DC voltage wakes-up the sensor out of a deep sleep mode. Several flight approaches are investigated and analyzed with vertical trajectory approaches exhibiting the most efficient energy collection

We report on the engineering of repeatable surface enhanced Raman scattering (SERS) probes realized through nanosphere lithography. The Lab-on-Fiber SERS probes consist of polystyrene nanospheres in close-packed arrays (CPA), covered by a thin film of gold, on the optical fiber tip.

In recent years, air pollution has been a subject of great scientific and public interests for the strong impact on human health. Air pollution is due to the presence in the atmosphere of polluting substances, such as carbon monoxide, sulfur and nitrogen oxides, particulates and volatile organic compounds (VOCs), derived predominantly from various combustion processes. Benzene is a VOC belonging to group-I carcinogens with a toxicity widely demonstrated. The emission limit values and the daily exposure time to benzene (TLV-TWA) are 5?g/m3 (0.00157 ppm) and 1.6mg/m3 (0.5 ppm), respectively. Currently, expensive and time-consuming analytical methods are used for detection of benzene. These methods require to perform a few preliminary steps such as sampling, and matrices pre-treatments. In addition, it is also needed the support of specialized personnel. Recently, single-walled carbon nanotube (SWNTs) gas sensors with a limit detection (LOD) of 20 ppm were developed for benzene detection. Other innovative bioassay, called bio-report systems, were proposed. They use a whole cell (Pseudomona putida or Escherichia coli) as molecular recognition element and exhibit a LOD of about 10 ?M. Here, we report on the design of a highly sensitive fluorescence assay for monitoring atmospheric level of benzene. For this purpose, we used as molecular recognition element the porcine odorant-binding protein (pOBP). 1-Aminoanthracene was selected as extrinsic fluorescence probe for designing a competitive fluorescence resonance energy transfer (FRET) assay for benzene detection. The detection limit of our assay was 3.9?g/m3, a value lower than the actual emission limit value of benzene as regulated by European law.

Traditional applications of metal organic frameworks (MOFs) are focused on gas storage and separation, which take advantage of the inherent porosity and high surface area of these materials. The application of MOFs as chemical sensors require signal transduction based on the dynamics of the analyte interacting with the MOF network. The main objective of our project is to design multifunctional (combination of optical and electrical signals) and dynamic Stimuli-Responsive Metal Organic Frameworks (SR-MOFs) with enhanced selectivity and sensitivity towards harmful volatile organic compounds (VOCs), to be integrated into sensory devices. We selected units that offer extensive connectivity, flexibility, tunable porosity and functionalization of the inner surface of the network, with groups interacting with the analytes by means of coordination bonds, p-p interactions or hydrogen bonds. We envisage that the new sensors will show increased selectivity and sensitivity towards VOCs with respect to the state-of-the-art. Preliminary results on the synthesis and structural and chemico-physical characterization of new MOFs obtained from thiolated ligands and CuI will be presented. References [1] P. Kumar, A. Deep, K. H. Kim, R. J. C. Brown, Prog. Polym. Sci. 45, 102, 2015. [2] Y. Yu, J. P. Ma, C. W. Zhao, J. Yang, X. M. Zhang, Q. K. Liu, Y. B. Dong, Inorg. Chem. 54, 2015. [3] I. Stassen, N. Burtch, A. Talin, P. Falcaro, M. Allendorf, R. Ameloot, Chem. Soc. Rev. 46, 3185, 2017. [4] M. G. Campbell; S. F. Liu, T. M. Swager, M. Dinc?, J. Am. Chem. Soc. 137, 13780, 2015. The work is supported by the H2020-MSCA-IF-2016-751175 project "SmartMOFs".

The KRAS oncogene is involved in the pathogenesis of several types of cancer, particularly colorectal cancer (CRC). The most frequent mutations in this gene are associated with poor survival, increased tumor aggressiveness and resistance to therapy with anti-epidermal growth factor receptor (EGFR) antibodies. For this reason, KRAS mutation testing has become increasingly common in clinical practice for personalized cancer treatments of CRC patients. Detection methods for KRAS mutations are currently expensive, laborious, time-consuming and often lack of diagnostic sensitivity and specificity. In this study, we describe the development of a Lab-on-Chip assay for genotyping of KRAS mutational status. This assay, based on the In-Check platform, integrates microfluidic handling, a multiplex polymerase chain reaction (PCR) and a low-density microarray. This integrated sample-to-result system enables the detection of KRAS point mutations, including those occurring in codons 12 and 13 of exon 2, 59 and 61 of exon 3, 117 and 146 of exon 4. Thanks to its miniaturization, automation, rapid analysis, minimal risk of sample contamination, increased accuracy and reproducibility of results, this Lab-on-Chip platform may offer immediate opportunities to simplify KRAS genotyping into clinical routine.

Biometrics provides an alternative paradigm for the personal authentication: our biological characteristics are unique and can be used to distinguish us from the other persons. Biometrics are automated methods of identifying a person or verifying the identity of a person based on a physiological or behavioral characteristic. Examples of physiological characteristics include hand or finger images, facial characteristics, and iris recognition. Behavioral characteristics are traits that are learned or acquired. Dynamic signature verification, speaker verification, and keystroke dynamics are examples of behavioral characteristics. In this paper a general overview of biometric systems based on the principal biometric technologies available and a description of a fingerprint recognition sensor performances are proposed. To test the biometric sensor performances two indexes are used, FAR (false accept rate) and FRR (false reject rate).

Carbon nanotubes (CNTs) have attracted the interest of the scientific research in several fields thanks to their intrinsic chemical-physical properties [1] and their cylindrical structure that make them, furthermore, capable of molecular transport. Thanks to their electrical properties, CNTs can be used in sensoristic and electronic fields, but at the same time, they can be considered as a viable alternative to traditional conductive inorganic materials. Indeed, CNTs are able to detect variations in environmental chemical composition [2] or toxic gas molecules at room temperature, and they can be employed for the realization of electric circuit for flexible and wearable electronics. Recently, the demand for conductive fabrics is increased both for the realization of "technical fabrics" [3] and "smart textiles" which provide applications in different fields such as sports, healthcare, military, security and so on. With the aim to combine the sensing and electronic features of CNTs with mechanical characteristics of a fabric, a humidity/temperature sensor cotton fabric based on a conductive coating containing Multi Walled Carbon Nanotubes (MWCNTs) dispersed in a polymer matrix has been designed. The realized MWCNTs-cotton based sensor was fully investigated by different chemicalphysical techniques in order to evaluate the morphology of the coating. Sensing properties were studied by measuring changing in the surface resistance (Rsheet) at different relative humidity and temperature conditions. In particular, Rsheet seems to be influenced by water molecules that interact with MWCNTs connections. Experimental findings demonstrated the sensing properties of the realized MWCNTs coating toward humidity and temperature and its potential employment as a component for a humidity/temperature sensor.