Personne :
Messaddeq, Younès

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Adresse électronique
Date de naissance
Projets de recherche
Structures organisationnelles
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Université Laval. Département de physique, de génie physique et d'optique
Identifiant Canadiana

Résultats de recherche

Voici les éléments 1 - 10 sur 23
  • Publication
    Accès libre
    Wearable contactless respiration sensor based on multi-material fibers integrated into textile
    (Molecular Diversity Preservation International (MDPI), 2017-05-06) Gorgutsa, Stepan; LaRochelle, Sophie; Messaddeq, Younès; Guay, Philippe
    In this paper, we report on a novel sensor for the contactless monitoring of the respiration rate, made from multi-material fibers arranged in the form of spiral antenna (2.45 GHz central frequency). High flexibility of the used composite metal-glass-polymer fibers permits their integration into a cotton t-shirt without compromising comfort or restricting movement of the user. At the same time, change of the antenna geometry, due to the chest expansion and the displacement of the air volume in the lungs, is found to cause a significant shift of the antenna operational frequency, thus allowing respiration detection. In contrast with many current solutions, respiration is detected without attachment of the electrodes of any kind to the user’s body, neither direct contact of the fiber with the skin is required. Respiration patterns for two male volunteers were recorded with the help of a sensor prototype integrated into standard cotton t-shirt in sitting, standing, and lying scenarios. The typical measured frequency shift for the deep and shallow breathing was found to be in the range 120–200 MHz and 10–15 MHz, respectively. The same spiral fiber antenna is also shown to be suitable for short-range wireless communication, thus allowing respiration data transmission, for example, via the Bluetooth protocol, to mobile handheld devices.
  • Publication
    Accès libre
    Laser-induced dewetting of silver-doped chalcogenide glasses
    (Elsevier, 2018-03-19) Messaddeq, Sandra Helena; Messaddeq, Younès; Boily, Olivier; Douaud, Alexandre
    We report the observation of laser-induced dewetting responsible for the formation of periodic relief structures in silver-based chalcogenide thin-films. By varying the concentration of silver in the Agx(As20S80)100−x system (with x = 0, 4, 9 and 36), different surface relief structures are formed. The evolution of the surface changes as a function of laser parameters (power density, duration of exposure, and polarisation) as well as film thickness and silver concentration has been investigated. The scanning electron microscopy and atomic force microscopy images of irradiated spots show periodic ripples aligned perpendicularly to the electric field of incident light. Our results show that addition of silver into sulphur-rich chalcogenide thin-films improves the dewetting when compared to pure As20S80 thin-films. The changes in surface morphology were attributable to photo-induced chemical modifications and a laser-driven molecular rearrangement.
  • Publication
    Accès libre
    Multimodal structural characterization of Ge−S−I glasses by combination of DFT calculation and IR and polarized Raman Spectroscopy
    (American Chemical Society, 2019-01-14) Chazot, Matthieu; Méreau, Raphaël; El Amraoui, Mohammed; Messaddeq, Younès; Adamietz, Frédéric; Rodriguez, Vincent
    From a dual experimental–theoretical vibrational analysis, we propose a new rationalized structural description of Ge–S–I chalcogenides glasses at the nanoscale. A vibrational multipolar approach based on a simultaneous deconvolution of infrared (IR) and polarized Raman spectra (RS-VV and RS-HV) has been applied on these glasses. According to recent results on the amorphous GeS2 structure by X-Ray and neutron diffraction and to our spectral analyses, we suggest that the local structure of the glass backbone is effectively described by a combination of α-GeS2 nanolayers, edge-sharing GeS4 tetrahedra (ES-Td, ca ∼50%), and corner-sharing GeS4 tetrahedra (CS-Td, ca ∼50%). We have then compared the experimental spectra to the calculated IR and polarized Raman spectra of some selected GexSyIz structural units obtained by density functional theory calculation. The stretching modes of the Ge–S–I occurring in the high frequency spectral range (300–450 cm–1) are essentially those of the GeS2 glass backbone and have been revisited. In addition, through a careful analysis of the vibrational multipolar activities of stoichiometric and over-stoichiometric sulfur glasses between 180 and 280 cm–1, we propose new assignments for the seven modes that have been identified by our trimodal spectral analysis. We finally suggest that there is a competition between the insertion of atomic iodine as a glass modifier which involves the Ge–S–I clusters and molecular diiodine as a spectator encaged between two α-GeS2 nanolayers.
  • Publication
    Accès libre
    Mode division multiplexing using orbital angular momentum modes over 1.4 km ring core fiber
    (Institute of Electrical and Electronics Engineers, 2016-07-27) Mirzaei Nejad, Reza; Amiralizadeh, Siamak; Brunet, Charles; LaRochelle, Sophie; Messaddeq, Younès; Allahverdyan, Karen; Rusch, Leslie; Vaity, Pravin
    Mode division multiplexing (MDM) systems using orbital angular momentum (OAM) modes can recover the data in D different modes without recourse to full (2D × 2D) multiple input multiple output (MIMO) processing. One of the biggest challenges in OAM-MDM systems is the mode instability following fiber propagation. Previously, MIMO-free OAM-MDM data transmission with two modes over 1.1 km of vortex fiber was demonstrated, where optical polarization demultiplexing was employed in the setup. We demonstrate MDM data transmission using two OAM modes over 1.4 km of a specially designed ring core fiber without using full MIMO processing or optical polarization demultiplexing. We demonstrate reception with electrical polarization demultiplexing, i.e., minimal 2 × 2 MIMO, showing the compatibility of OAM-MDM with current polarization demultiplexing receivers.
  • Publication
    Accès libre
    Orbital-angular-momentum polarization mode dispersion in optical fibers
    (Institute of Electrical and Electronics Engineers, 2016-04-15) LaRochelle, Sophie; Messaddeq, Younès; Chatigny, Stephane; Wang, Lixian; Rusch, Leslie; Vaity, Pravin
    The orbital-angular-momentum (OAM) modes in optical fibers have polarization mode dispersion (PMD) properties similar to those of single-mode fibers (SMFs). The +l and -l order OAM modes supported by the same fiber vector modes undergo random cross coupling and exhibit a frequency-dependent time delay. We name this effect “OAM-PMD” and extend the formalism developed for PMD in SMFs to describe OAM-PMD. The characteristics of the modal beat lengths, birefringence correlation lengths, and the mean value of OAM-PMD are investigated. A fixed-analyzer technique is proposed and demonstrated to characterize this phenomenon in OAM fibers. Two different types of OAM fiber are examined. The measured results are compared with the theoretical calculations.
  • Publication
    Carbonic anhydrase XII in valve interstitial cells promotes the regression of calcific aortic valve stenosis.
    (Academic Press Inc, Ltd., 2016-03-11) Lachance, Dominic.; Bouchareb, Rihab; Asselin, Jérémie; Boudreau, Denis; Marette, André; Boulanger, Marie-Chloé; Le Quang, Khai; Côté, Nancy.; Bossé, Yohan; Shayhidin, Elnur Elyar; Messaddeq, Younès; El Husseini, Diala; Mahmut, Ablajan; Pibarot, Philippe; Hadji, Fayez; Mathieu, Patrick
    Aims: Calcific aortic valve stenosis (CAVS) is the most common heart valve disease. In the present work we sought to determine the reversibility of mineralization in the aortic valve. Methods and results: By using in vitro analyses we found that valve interstitial cells (VICs) have the ability to resorb minerals. We documented that agonist of P2Y2 receptor (P2Y2R) promoted the expression of carbonic anhydrase XII (CAXII) at the cell membrane of VICs, whereby minerals are resorbed. P2Y2R-mediated mineral resorption was corroborated by using mouse VICs isolated from wild type and P2Y2R-/- mice. Measurements of extracellular pH (pHe) by using core–shell nanosensors revealed that P2Y2R-mediated CAXII export to the cell membrane led to an acidification of extracellular space, whereby minerals are resorbed. In vivo, we next treated LDLR-/-/ApoB100/100/IGF2 mice, which had developed CAVS under a high-fat/high-sucrose diet for 8 months, with 2-thioUTP (a P2Y2R agonist) or saline for the next 2 months. The administration of 2-thioUTP (2 mg/kg/day i.p.) reduced the mineral volume in the aortic valve measured with serial microCT analyses, which improved hemodynamics and reduced left ventricular hypertrophy (LVH). Examination of leaflets at necropsy confirmed a lower level of mineralization and fibrosis along with higher levels of CAXII in mice under 2-thioUTP. In another series of experiment, the administration of acetazolamide (a CA inhibitor) prevented the acidification of leaflets and the regression of CAVS induced by 2-thioUTP in LDLR-/-/ApoB100/100/IGF2 mice. Conclusion: P2Y2R-mediated expression of CAXII by VICs acidifies the extracellular space and promotes the regression of CAVS.
  • Publication
    Mechanical strain induces the production of spheroid mineralized microparticles in the aortic valve through a RhoA/ROCK-dependent mechanism.
    (Academic Press Inc, Ltd., 2013-12-22) Bouchareb, Rihab; Fournier, Dominique; Boulanger, Marie-Chloé; Messaddeq, Younès; Pibarot, Philippe; Mathieu, Patrick
    Calcific aortic valve disease (CAVD) is a chronic disorder characterized by an abnormal mineralization of the leaflets, which is accelerated in bicuspid aortic valve (BAV). It is suspected that mechanical strain may promote/enhance mineralization of the aortic valve. However, the effect of mechanical strain and the involved pathways during mineralization of the aortic valve remains largely unknown. Valve interstitial cells (VICs) were isolated and studied under strain conditions. Human bicuspid aortic valves were examined as a model relevant to increase mechanical strain. Cyclic strain increased mineralization of VICs by several-fold. Scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analyses revealed that mechanical strain promoted the formation of mineralized spheroid microparticles, which coalesced into larger structure at the surface of apoptotic VICs. Apoptosis and mineralization were closely associated with expression of ENPP1. Inhibition of ENPP1 greatly reduced mineralization of VIC cultures. Through several lines of evidence we showed that mechanical strain promoted the export of ENPP1-containing vesicles to the plasma membrane through a RhoA/ROCK pathway. Studies conducted in human BAV revealed the presence of spheroid mineralized structures along with the expression of ENPP1 in areas of high mechanical strain. Mechanical strain promotes the production and accumulation of spheroid mineralized microparticles by VICs, which may represent one important underlying mechanism involved in aortic valve mineralization. RhoA/ROCK-mediated export of ENPP1 to the plasma membrane promotes strain-induced mineralization of VICs.
  • Publication
    Accès libre
    Analysis of inter-core cross-gain modulation in cladding pumped multi-core fiber amplifiers
    (IEEE Xplore, 2018-11-15) Essiambre, René-Jean.; Chen, Haoshuo; Matte-Breton, Charles; Fontaine, Nicolas K.; LaRochelle, Sophie; Ryf, Roland; Messaddeq, Younès
    We numerically investigate pump-induced gain variations in eight-core fi ber amplifi ers. We compare two fi bers with different erbium profi les by varying input power from -25 dBm to 0 dBm in one or four cores. Inter-core cross-gain modulation is < 0.6 dB.
  • Publication
    Accès libre
    The EcoChip : a wireless multi-sensor platform for comprehensive environmental monitoring
    (IEEE, 2018-10-31) Tremblay, Denise; Gosselin, Benoit; Morency, Steeve; Faucher, Félix; Sarrazin, Denis; Moineau, Sylvain; Corbeil, Jacques; Sylvain, Matthieu; Messaddeq, Younès; Allard, Michel; Lehoux, Francis; Bharucha, Eric; Raymond, Frédéric
    This paper presents the EcoChip, a new system based on state-of-the-art electro-chemical impedance (EIS) technologies allowing the growth of single strain organisms isolated from northern habitats. This portable system is a complete and autonomous wireless platform designed to monitor and cultivate microorganisms directly sampled from their natural environment, particularly from harsh northern environments. Using 96-well plates, the EcoChip can be used in the field for realtime monitoring of bacterial growth. Manufactured with highquality electronic components, this new EIS monitoring system is designed to function at a low excitation voltage signal to avoid damaging the cultured cells. The high-precision calibration network leads to high-precision results, even in the most limiting contexts. Luminosity, humidity and temperature can also be monitored with the addition of appropriate sensors. Access to robust data storage systems and power supplies is an obvious limitation for northern research. That is why the EcoChip is equipped with a flash memory that can store data over long periods of time. To resolve the power issue, a low-power microcontroller and a power management unit control and supply all electronic building blocks. Data stored in the EcoChip’s flash memory can be transmitted through a transceiver whenever a receiver is located within the functional transmission range. In this paper, we present the measured performance of the system, along with results from laboratory tests in-vitro and from two field tests. The EcoChip has been utilized to collect bio-environemental data in the field from the northern soils and ecosystems of Kuujjuarapik and Puvirnituq, during two expeditions, in 2017 and 2018, respectively. We show that the EcoChip can effectively carry out EIS analyses over an excitation frequency ranging from 750 Hz to 10 kHz with an accuracy of 2.35%. The overall power consumption of the system was 140.4 mW in normal operating mode and 81 µW in sleep mode. The proper development of the isolated bacteria was confirmed through DNA sequencing, indicating that bacteria thrive in the EcoChip’s culture wells while the growing conditions are successfully gathered and stored.
  • Publication
    Accès libre
    Modeling and characterization of cladding-pumped erbium-ytterbium co-doped fibers for amplification in communication systems
    (Institute of Electrical and Electronics Engineers, 2019-12-20) Essiambre, René-Jean.; Ryf, Roland; Matte-Breton, Charles; Fontaine, Nicolas K.; LaRochelle, Sophie; Messaddeq, Younès; Chen, Haoshuo; Kelly, C.
    Cladding-pumped optical fiber amplifiers are of increased interest in the context of space-division multiplexing but are known to suffer from low power efficiency. In this context, ytterbium (Yb) co-doping can be an attractive solution to improve the performance of erbium (Er) doped fiber amplifiers. We present a detailed direct comparison between Er/Yb-co-doping and Er-doping using numerical simulations validated by experimental results. Two double-cladding fibers, one doped with Er only and the other one co-doped with Er and Yb, were designed, fabricated and characterized. Using the experimentally extracted parameters, we simulate multi-core fiber amplifiers and investigate the interest of Er/Yb-co-doping. We calculate the minimum gain of the amplifiers over a 35-nm spectral window considering various scenarios.