Pierre Lucas

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Health risks associated with the inhalation of biological materials have been a topic of great concern; however, there are no rapid and automatable methods available to evaluate the potential health impact of inhaled materials. Here we describe a novel approach to evaluate the potential toxic effects of materials evaluated through cell-based spectroscopic(More)
The fragility index (m) of a series of Ge-As-S glasses covering a wide range of mean coordination (⟨r⟩) and stoichiometry is measured by differential scanning calorimetry. The evolution of the fragility index appears to be better predicted by the stoichiometry than the mean coordination, and m shows a well-defined dependence on the departure from(More)
The structural relaxation properties of 34 compositions of Ge-As-Se glass forming liquids are investigated by differential scanning calorimetry (DSC). The fragility index (m) and activation energies for enthalpy relaxation (Ea) exhibit universal trends with respect to stoichiometry and mean coordination (⟨r⟩), respectively. The liquid fragility which(More)
Biogenic amines (BA) are a group of organic nitrogenous compounds formed and degraded by the metabolism of living organisms (microorganisms, plants and animals). The main BA associated with wine are putrescine, histamine, tyramine and cadaverine, followed by phenylethylamine, spermidine, spermine, agmatine and tryptamine. The variability in the BA content(More)
Biochemical changes in living cells are detected using a fiber probe system composed of a single chalcogenide fiber acting as both the sensor and transmission line for infrared optical signals. The signal is collected via evanescent wave absorption along the tapered sensing zone of the fiber. We spectroscopically monitored the effects of the surfactant(More)
Sub-band-gap irradiation of a series of bulk Ge-As-Se glass samples with a tunable laser source shows that photostructural processes in chalcogenide glasses are strongly dependent on the covalent network connectivity. The photoexcitation process is affected by the bond density as well as the network rigidity. Photostructural changes such as photodarkening(More)
The goal of this work is to develop an online monitoring scheme for detection of viruses in flowing drinking water. The approach applies an electrodeposition process that is similar to the use of charged membrane filters previously employed for collection of viruses from aqueous samples. In the present approach, charged materials are driven onto a robust(More)
Conventional glasses based on oxides have a transparency limited by phonon absorption in the near IR region and have a limited interest for analyzing information located far beyond the visible. The IR spectral domain is nevertheless of prime interest, since it covers fundamental wavelength ranges used for thermal imaging as well as molecular vibrational(More)
Two symmetric, convecting steady states have been observed in a novel cell of unity aspect ratio and studied over a range of temperature for two concentrations of (3)He in superfluid (4)He. An existing theory due to Parshin has been related to the conditions necessary for convection in this system, defining a Rayleigh number closely analogous to that of a(More)