About extension of upper semicontinuous multi-valued maps and applications

We formulate a multi-valued version of the Tietze-Urysohn extension theorem. Precisely, we prove that any upper semicontinuous multi-valued map with nonempty closed convex values defined on a closed subset (resp. closed perfectly normal subset) of a completely normal (resp. of a normal) space $X$ into the unit interval $[0,1]$ can be extended to the whole space $X$. The extension is upper semicontinuous with nonempty closed convex values. We apply this result for the extension of real semicontinuous functions, the characterization of completely normal spaces, the existence of Gale-Mas-Colell and Shafer-Sonnenschein type fixed point theorems and the existence of equilibrium for qualitative games

The volume scanner optical performance

The optical performance of a volume scanner is analyzed using modelling software. The existence of an embedded scattering volume with a 2.5% difference in scattering coefficient from the host media may be detected

Numerical Study of Light Transport in Apple Models Based on Monte Carlo Simulations

International audienceThis paper reports on the quantification of light transport in apple models using Monte Carlo simulations. To this end, apple was modeled as a two-layer spherical model including skin and flesh bulk tissues. The optical properties of both tissue types used to generate Monte Carlo data were collected from the literature, and selected to cover a range of values related to three apple varieties. Two different imaging-tissue setups were simulated in order to show the role of the skin on steady-state backscattering images, spatially-resolved reflectance profiles, and assessment of flesh optical properties using an inverse nonlinear least squares fitting algorithm. Simulation results suggest that apple skin cannot be ignored when a Visible/Near-Infrared (Vis/NIR) steady-state imagingsetupisusedforinvestigatingqualityattributesofapples. Theyalsohelptoimproveoptical inspection techniques in the horticultural products

Zinc oxide nanoparticles inhibits quorum sensing and virulence in Pseudomonas aeruginosa

Background: Quorum sensing inhibitionis an advanced strategy that aims to interfere with bacterial cell-to-cell communication systems (quorum sensing), which regulate virulence factors production in Pseudomonas aeruginosa, in order to overcome the globalcrisis of antimicrobial resistance.Objectives: Study the potential quorum sensing inhibitory effect of Zinc oxide (ZnO)nanoparticlesin Pseudomonas aeruginosa and the impact on production of virulence factors.Methods: Quorum sensing inhibitory effect of ZnO was evaluated by assessing its ability to reducePseudomonas aeruginosa virulence factors production; rhamnolipids, pyocyanin, pyoverdin, hemolysins, elastase and proteases. Furthermore, qRT-PCR was performed to determine ZnO inhibitory effect onQS-regulatory geneslasI, lasR,rhlI, rhlR, pqsA and pqsR that control virulence factors secretion. Moreover, mice survival test was conducted to investigate the influence of ZnO on Pseudomonas aeruginosa-induced mortality in vivo.Results: ZnO revealed a statistically significant reduction in the production of QS-controlled virulence factors rhamnolipids, pyocyanin, pyoverdin, hemolysins, elastase and proteases. Furthermore, ZnO exhibited a significant decrease in the relative expression of QS-regulatory geneslasI, lasR,rhlI, rhlR,pqsA and pqsR. Additionally, ZnO significantly reduced the pathogenesis of Pseudomonas aeruginosa in vivoConclusion: ZnO nanoparticles can be used as a quorum sensing inhibitor in Pseudomonas aeruginosa infections either as an adjuvant or alternative to conventional antimicrobials.Keywords: Pseudomonas aeruginosa, ZnO, quorum sensing, virulence inhibition

Experimental Study of Light Propagation in Apple Tissues Using a Multispectral Imaging System

This work aimed at high lighting the role played by the skin in the light propagation through the apple flesh. A multispectral Visible-Near Infrared (Vis-NIR) steady-state imaging setup based on the use of four continuous laser sources (633, 763, 784, and 852 nm) and a charge–coupled–device (CCD) camera was developed to record light diffusion inside apple tissues. Backscattering images and light reflectance profiles were studied to reveal optical features of three whole and half-cut apple varieties with and without skin. The optical absorption and scattering properties (µa, µ’s) of intact apples and peeled apples were also retrieved in reflectance mode, using an optimal sensing range of 2.8–10 mm. A relative difference for ∆µa ranging from 3.4% to 24.7% was observed for intact apples with respect to peeled apples. Under the same conditions, no significant changes were noted for ∆µ’s, which ranged from 0.1% to 1.7%. These findings show that the apple skin cannot be ignored when using Vis-NIR optical imaging as a non-destructive sensing means to reveal major quality attributes of fruits