This paper presents a new non-contact method to measure vibrations using a low cost optical approach, yet able to provide sub-micrometer resolution. The transducer exploits a simple optical setup based on an intensity detection scheme implemented with plastic optical fibers, while innovative non-demanding spectral data processing allows compensating for the vibrating surface reflectivity and the gains of the measurement chain. The performance of the proposed system have been assessed, through the comparison with other techniques, performing several measurement tests using targets vibrating at frequencies from few hertz up to several tens of kilohertz and with different values of reflectivity.

Elemental carbon nanomaterials (ECNMs) are redox active agents that can be exploited to purposely modify the redox balance of cells. Both pro-or antioxidant properties have been reported. However, to the best of our knowledge, there are not comprehensive studies exploring both properties on the same material in view of a potential application in medicine. At the same time, the effect of the bulk structure on the pro/antioxidant properties is poorly known. Here, carbon nanoparticles (CNPs) derived by glucose with definite size and shape have been prepared, and their redox properties evaluated in cell free systems in the dark or following activation with a Near Infrared (NIR) laser beam (945 nm, 1.3 W/cm 2 ). We found that, when irradiated with NIR, CNPs efficiently generate heat and singlet oxygen ( 1 O2), a property that can be exploited for dual photo-thermal (PT)/ photodynamic (PD) therapy in cancer. On the other hand, in the absence of photo-activation, CNPs react with both oxidant (hydroxyl radicals) and antioxidant (glutathione) species. When tested on a murine macrophages cell line (RAW 264.7) CNPs were clearly antioxidant. Furthermore, albeit efficiently internalized, CNPs do not exert cytotoxic effect up to 80 µg/ml and do not exacerbate TNF-α-mediated inflammation. Overall, the results reported herein suggest that CNPs may represent a new class of safe nanomaterials with potential applications in medicine.

No abstract

The use of indium tin oxide (ITO) thin films as electrodes for integrated optical electrochemical sensor devices is discussed. The effect of various thicknesses of ITO overlayers exhibiting low resistivity and high transparency on potassium ion-exchanged waveguides fabricated in glass substrates is investigated over the wavelength range 500-900 nm. ITO overlayers are formed by reactive thermal evaporation in oxygen, followed by annealing in air to a maximum temperature of 320 C. With air as superstrate, losses in the waveguides were found to o increase dramatically above 30nm ITO thickness for TE polarization, and above 50nm thickness for TM. Losses were increased over the whole wavelength range for a superstrate index close to that of water. A one-dimensional multilayer waveguide model is used in the interpretation of the experimental results.

No abstract

No abstract

A fiber Bragg grating (FBG) vibroacoustic sensor exploiting an intensity-based interrogation principle is presented. The optical system is complemented by signal processing techniques that allow disturbances to be mitigated and improve the spectral estimation. The sensor is capable of performing frequency analysis of sounds up to 3 kHz, with top sensitivity in the 100-500 Hz frequency range, and of dynamically tracking pulsed phenomena that induce a strain to the FBG. The sensor has been applied to the detection of voice, showing a great intelligibility of the speech despite the low-quality environment, and to the monitoring of the heartbeat rate from the wrist.

The paper presents the characterization results of a new all-optical applicator for improved tumor laser ablation treatments that features customized irradiation pattern and builtin temperature sensors. The probe exploits a double cladding optical fiber to integrate some Bragg gratings acting as temperature sensing elements in the core, while guiding the high power beam used for the ablation in the inner cladding. The assessment of the probe behavior has been conducted in two steps: first, with an agar gel phantom to characterize the irradiation pattern and to validate the Bragg grating based measurement setup in comparison with a thermographic camera; then, simulating actual treatments using an ex-vivo animal liver.