Impact of toxic cyanobacteria on gastropods and microcystin accumulation in a eutrophic lake (Grand-Lieu, France) with special reference to Physa (= Physella) acuta

Hepatotoxic microcystins (MCs) produced by cyanobacteria are known to accumulate in gastropods following grazing of toxic cyanobacteria and/or absorption of MCs dissolved in water, with adverse effects on life history traits demonstrated in the laboratory. In the field, such effects may vary depending on species, according to their relative sensitivity and ecology. The aims of this study were to i) establish how various intensities of MC-producing cyanobacteria proliferations alter the structure of gastropod community and ii) compare MC tissue concentration in gastropods in the field with those obtained in our previous laboratory experiments on the prosobranch Potamopyrgus antipodarum and the pulmonate Lymnaea stagnalis. We explored these questions through a one-year field study at three stations at Grand-Lieu Lake (France) affected by different intensities of cyanobacteria proliferations. A survey of the community structure and MC content of both cyanobacteria and gastropods was associated with a caging experiment involving P. antipodarum and L. stagnalis. In total, 2592 gastropods belonging to 7 prosobranch and 16 pulmonate species were collected. However, distribution among the stations was unequal with 62% vs 2% of gastropods sampled respectively at the stations with the lowest vs highest concentrations of MC. Irrespective of the station, pulmonates were always more diverse, more abundant and occurred at higher frequencies than prosobranchs. Only the pulmonate Physa acuta occurred at all stations, with abundance and MC tissue concentration (≤ 4.32 µg g DW^− 1) depending on the degrees of MC-producing cyanobacteria proliferations in the stations; therefore, P. acuta is proposed as a potential sentinel species. The caging experiment demonstrated a higher MC accumulation in L. stagnalis (≤ 0.36 µg g DW^− 1 for 71% of individuals) than in P. antipodarum (≤ 0.02 µg g DW^− 1 for 12%), corroborating previous laboratory observations. Results are discussed in terms of differential gastropod sensitivity and MC transfer through the food web.     

Proposed Framework for Evaluating Quality of Experience in a Mobile,Testbed-oriented Living Lab Setting

The framework presented in this paper enables the evaluation of Quality of Experience (QoE) in a mobile, testbed-oriented Living Lab setting. As a result, it fits within the shift towards more user-centric approaches in innovation research and aims to bridge the gap between technical parameters and human experience factors. In view of this, Quality of Experience is seen as a multi-dimensional concept, which should be considered from an interdisciplinary perspective. Although several approaches for evaluating perceived QoE have been proposed in the past, they tend to focus on a limited number of objective dimensions and fail to grasp the subjective counterparts of users’ experiences. We therefore propose a distributed architecture for monitoring network Quality of Service (QoS), context information and subjective user experience based on the functional requirements related to real-time experience measurements in real-life settings. This approach allows us to evaluate all relevant QoE-dimensions in a mobile context.     

Brillouin distributed time-domain sensing in optical fibers: state of the art and perspectives

Optical fiber sensors based on stimulated Brillouin scattering have now clearly demonstrated their excellent capability for long-range distributed strain and temperature measurements. The fiber is used as sensing element, and a value for temperature and/or strain can be obtained from any point along the fiber. After explaining the principle and presenting the standard implementation, the latest developments in this class of sensors will be introduced, such as the possibility to measure with a spatial resolution of 10 cm and below while preserving the full accuracy on the determination of temperature and strain.     

Crystal Structure of the Human Monoacylglycerol Lipase,a Key Actor in Endocannabinoid Signaling

2‐Arachidonoylglycerol plays a major role in endocannabinoid signaling, and is tightly regulated by the monoacylglycerol lipase (MAGL). Here we report the crystal structure of human MAGL. The protein crystallizes as a dimer, and despite structural homologies to haloperoxidases and esterases, it distinguishes itself by a wide and hydrophobic access to the catalytic site. An apolar helix covering the active site also gives structural insight into the amphitropic character of MAGL, and likely explains how MAGL interacts with membranes to recruit its substrate. Docking of 2‐arachidonoylglycerol highlights a hydrophobic and a hydrophilic cavity that accommodate the lipid into the catalytic site. Moreover, we identified Cys201 as the crucial residue in MAGL inhibition by N‐arachidonylmaleimide, a sulfhydryl‐reactive compound. Beside the advance in the knowledge of endocannabinoids degradation routes, the structure of MAGL paves the way for future medicinal chemistry works aimed at the design of new drugs exploiting 2‐arachidonoylglycerol transmission.     

Air filtration performance of nanofiber membranes with different morphologies produced by green electrospinning

To further target product development with low environmental impact, an integral green electrospinning (G-ES) approach has been adopted through the simultaneous application of various strategies, such as the use of biopolymers, reduction of energy use to avoid melting temperatures, and selection of non-toxic solvents and surfactants. Green solubility spinnability maps for cellulose acetate (CA), poly ε-caprolactone (PCL), and polyvinyl alcohol (PVA) are presented. Green electrospinning (G-ES) allows the production of new morphologies for CA and PCL nanofiber membranes. In this work, CA exhibits a ribbon-like morphology, PCL shows a honeycomb-like morphology and PVA cylindrical fibers. Membrane morphologies are compared with filtration efficiency (FE) for particle size of 1.0 μm and quality factor (Q_F) at a volumetric flux of 27.63 cm⁻¹. For CA is between 83% and 96% and high Q_F = 0.31–0.38 Pa⁻¹, PCL is 92% and 99% and high Q_F = 0.28–0.21 Pa⁻¹ and for PVA between 96% and 99% and high Q_F = 0.14–0.08 Pa⁻¹. These results suggest that the hierarchical nanofiber structure improves filtration performance because of the reduction in pressure drop and increase in PM interception. CA ribbon-like fibers favored air filtration performance, followed by PCL honeycomb-like fibers.     

Simultaneous optimization of the mechanical properties of postconsumer natural fiber/plastic composites: Phase compatibilization and quality/cost ratio

In this work, a simultaneous optimization by phase compatibilization of four mechanical proprieties (flexural and tensile moduli, impact strength, and tensile stress at yield) of natural fiber/plastic composites was performed with respect to raw materials cost. In particular, a recycled resin of postconsumer origin (blend of high density polyethylene and polypropylene) with flax fibers was extruded with an additives package: a coupling agent (maleic anhydride grafted polypropylene) and an impact modifier (maleic anhydride grafted ethylene octene metallocene copolymer) to improve the interface between each phase. Then, the compounds were injection molded and tested. The analysis was performed according to a Box‐Behnken experimental design to study the effect of fiber concentration, total additives concentration, and impact modifier fraction in the additives package. The optimization process required three steps: to model the relationships between mechanical properties and selected factors by a multiple linear regression analysis, to identify the potentially optimum conditions using the desirability function approach (Derringer–Suich and Ch'ng et al.), and to determine the best composite composition (optimum condition) by a comparative analysis of the material quality/cost ratios. POLYM. COMPOS., 35:730–746, 2014. © 2013 Society of Plastics Engineers     

Control Optimization of a Slotted Switched Reluctance Generator for High-torque Applications

This article describes the control optimization of a slotted switched reluctance generator for low-speed applications. The machine is simulated with the finite-element method. The turn-off and turn-on angles are optimized by means of a genetic algorithm to maximize the output power and minimize the torque ripple. First, these two criteria are optimized separately with a mono-objective genetic algorithm, and then a multi-objective Pareto genetic algorithm is used. An analysis of optimized parameters and resulting current waveforms is also performed. Experimental results based on a 6/4 switched reluctance generator are also presented.     

Reflective direct-view LCDs using polymer-dispersed liquid crystal (PDLC) and dielectric reflectors

Abstract— Novel color and monochrome reflective direct-view display configurations have been developed by combining light-scattering PDLC layers with dielectric reflectors. Diffuse reflectances comparable to white paper were achieved.     

Thermal stress–strain of self‐compacting concrete in compression

Self‐compacting concrete or self‐consolidation concrete (SCC) is being used in underground and other industrial structures that may be subjected to high temperatures during operation or in case of an accidental fire. The proper understanding of the effects of elevated temperatures on the stress–strain relationship of SCC is necessary in the assessment of structural safety. This paper presents the high temperature behavior from an experimental study carried out on SCC subjected to high temperatures. The effects of temperature, strength grade, and polypropylene (PP) fibers on the initial elastic modulus, strain at peak stress, and stress–strain curves of SCC are studied, which offered a test basis for estimating the deformation of SCC under high temperature. An empirical constitutive formula for the thermal stress–strain of SCC is developed on the basis of the deformation characteristics of PP fiber‐modified SCC. Copyright © 2012 John Wiley & Sons, Ltd.