100 research outputs found
A new method based on biophotonic instrumentation for environmental monitoring
No full textA new approach to environmental monitoring is presented in this work, related to the use of a biophotonic instrument to support evaluation of lichens stress status. Lichens are widely used as bioindicators, that is organisms able to indicate the presence and amount of atmospheric pollutants. The proposed approach requires the measure of lichens fluorescence response by means of a self-developed biophotonic instrument, in order to obtain an objective evaluation of lichens stress status. The lichens rise fluorescence response was measured, following the OJIP procedure, a standardized laboratory method for plants health analysis. The experimental validation of this approach was done in two steps. Firstly, lichens of "Physcia Adscendens" species were collected on poplar trees, in tree areas: the first and the second areas near an industrial zone, direction of the prevailing winds, the third at a distance of about ten kilometers. Then the changes in fluorescence activity were evaluated, placing near an industrial area several samples of "Flavoparmelia Caperata (L.) Hale" lichens, collected in a non-polluted area. A fluorescence response modification was observed, demonstrating that changes in atmospheric pollution could be monitored by means of differential measurements on suitable samples. To validate the obtained results, the pollution degree was estimated using also a widely accepted method, which is the evaluation of lichen biodiversity. Lichen vegetation of the poplar trees was surveyed using a sampling grid of ten units. The Lichen Biodiversity Index (LBI) was calculated as the sum of the frequencies of all species within the grid. As a result of the comparison between fluorescence response shape and LBI evaluation, a real correlation was found, demonstrating the proposed approach effectiveness
Power absorption and temperature elevations induced in the human head by dual-band phones
No full textA numerically efficient way to evaluate SAR deposition and temperature elevation inside the head of a user of a cellular phone equipped with a dual-band helical antenna is proposed. The results obtained for a given radiated power show that, although the maximum SAR value as averaged over 1 g in the brain is higher at 900 MHz than at 1800 MHz, the maximum temperature increase in the brain is higher at 1800 MHz. In fact, at 1800 MHz the thermal diffusion process moves heat from the external layers, where SAR values higher than those obtained at 900 MHz are present, toward the brain
DEVELOPMENT OF A MICROWAVE SENSOR FOR IN-VITRO CELL LINES DETECTION: A PRELIMINARY STUDY
No full textAn Experimental Platform for the Analysis of Polydisperse Systems Based on Light Scattering and Image Processing
No full textIn this work an experimental platform for light scattering analysis has been developed using image sensors, as CCD or CMOS. The main aim of this activity is the investigation of the feasibility of using these types of sensors for polydisperse systems analysis. The second purpose is the implementation of an experimental platform which is enough versatile to permit the observation of different phenomena in order to develop novel sensors/approach using data fusion
SECONDARY STRUCTURES OF SHORT PEPTIDE CHAINS IN THE GAS PHASE AS REVEALED BY IR/UV DOUBLE RESONANCE SPECTROSCOPY
No full text{W. Chin, M. Mons, J.-P. Dognon, F. Piuzzi, B. Tardivel and I. Dimicoli, \textit{Phys. Chem. Chem. Phys.{W. Chin, J.-P. Dognon, F. Piuzzi, B. Tardivel, I. Dimicoli and M. Mons, \textit{J. Am. Chem. Soc.Author Institution: Laboratoire Francis Perrin (URA CNRS 2453), Service des; Photons, Atomes et Molecules, Centre d'Etudes de Saclay,; Bat. 522, 91191 Gif-sur-Yvette Cedex, FranceThe flexibility of peptide chains and their sensitivity to environment are key properties for the biological function of these molecules. Chemically protected peptides are short chains mimicking protein segments and are therefore suitable models, whose complicated conformational landscape have been studied so far only theoretically. The coupling of a laser-desorption device to a supersonic expansion provides a unique opportunity to perform a cooling-assisted folding of these peptides in the gas phase and then to characterise by IR-UV double resonance spectroscopy the H-bonding network of their most stable conformations. A bottom-up approach, based on the investigation of species of increasing size, has allowed us to characterize the local conformational preferences of these species and to address the issue of the emergence of secondary structures. In particular, with the help of quantum chemistry energetic and IR calculations, gas phase IR signatures in the amide A region (NH stretches around 3m) of the C5, C7 and C10 interactions between NH and CO groups along the chain have been determined. These are responsible for the -strand, -turn} \underline{\textbf{6}}, 2700 (2004).} and -turn} \underline{\textbf{127}}, 707 (2005).} secondary structures of proteins, respectively. Two main issues will be discussed: - The spontaneous formation under environment-free conditions of the secondary structures of proteins (in particular - and -turns), which are therefore intrinsic folding properties of these biomolecules. - The extreme sensitivity of the nature of the most stable conformations to the presence of backbone/side-chain or side-chain/side-chain interactions
Castelli senza continuità. Strutture fortificate e insediamento nell'alta valle del Tagliamento dalla tarda antichità al medioevo
No full textDevelopment of a novel SNOM probe for in liquid biological samples
No full textThis paper presents the design of a Scanning Near-field Optical Microscopy (SNOM) probe for the use with specimen in liquid environment. The approach is based on a first electro-mechanical characterization of existing SNOM probes. A modeling stage has permitted to identify and optimize critical probe parameters in order to improve SNOM sensitivity: development and implementation of SNOM probes for air and in liquid environments have been verified with imaging of both standard and soft samples
Investigation of wearable SENSIPLUS chip for bioimpedance measurements
No full textBioimpedance has emerged as a versatile and non-invasive diagnostic methodology for monitoring various physiological conditions of the human body. In this context, the detailed characterization of sensors dedicated to bioimpedance measurements is crucial to ensure the accuracy and reliability of the obtained results. In this paper a comprehensive study is proposed, suggesting the use of the SENSIPLUS chip, developed by Sensichips s.r.l., as a multifunctional microchip equipped with a precision LCR meter for low-noise impedance measurements up to 2.5 MHz, to measure inductance (L), capacitance (C) and resistance (R). Through comparative analysis with a professional LCR meter, measurements were performed on electrical circuits resembling the frequency behavior of human tissues. The reported results show a good overlap for both the resistance and reactance values, with errors well within tolerance limits. Moreover, an in-depth analysis of measurement repeatability highlights consistency and reproducibility, reinforcing the reliability of the chip in bioimpedance measurements. This study represents a promising step towards the integration in wearable devices of the SENSIPLUS chip as highly-accurate bioimpedance sensor for applications in the field of Internet of Medical Things (IoMT)
CHIRAL DISCRIMINATION IN JET-COOLED VAN DER WAALS COMPLEXES: ELECTRONIC AND VIBRATIONAL SPECTROSCOPY
No full textM. Mons, F. Piuzzi, I. Dimicoli, A. Zehnacker, F. Lahmani. Phys. Chem. Chem. Phys. 2 5065 (2000). K. Le Barbu, V. Brenner, Ph. Millie, F. Lahmani, A. Zehnacker-Rentien, J. Phys. Chem. A 102 128 (1998).Author Institution: Dept. of Chemistry, Laboratoire de Photophysique Moleculaire du CNRSChiral discrimination plays a key-role in life-chemistry and takes place through the formation of contact pairs implying short-range stereospecific interactions: spectroscopic measurements of jet-cooled van der Waals complexes of chiral molecules therefore provides a powerful strategy for addressing the question of chiral . We present here a study of hydrogen-bonded complexes of chiral molecules by double resonance techniques, either UV/UV (hole burning or IR/UV fluorescence depletion spectra. Besides an spectroscopic means of discriminating between two enantiomers, the results presented here, coupled with DFT calculations, bring information on the nature of the forces responsible for chiral recognition. The role of the formation of a hydrogen-bonds network in chiral discrimination will be discussed
Effect of capping groups at the N- and C-termini on the conformational preference of α,β-peptoids
No full textinvitation, special theme issue on Foldamer ChemistryInternational audienc
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