A new convolution approach for the time-delay identification of systems with arbitrary entries

In this paper, an online delay identification approach of continuous-time linear systems with unstructured entries is achieved via a new algebraic technique. The arbitrary input and output trajectories are chosen with close and abundant crossing zero. Initial conditions and static disturbances are taken into account in the design of the identification approach. The proposed method is based on a distributional algebraic technique and a convolution approach. A proposed theorem is hence enounced to identify a single time-delay of such systems. The effectiveness of the proposed approach is demonstrated by an illustrative example. The obtained results show the high performances of the proposed time-delay identification approach in severe operation conditions of the considered system.     

Lovastatin disrupts early events in insulin signaling: a potential mechanism of lovastatin's anti-mitogenic activity

The mechanism by which lovastatin lowers cholesterol levels is well characterized but little is known about its anti-mitogenic and anti-tumorigenic mechanism. Here we demonstrate that lovastatin disrupts early events in the mitogenic signaling pathways of insulin. Insulin treatment (200 mM) of quiescent HIR rat-1 fibroblasts results in an 8-fold stimulation of phosphatidylinositol-3-kinase (PI-3-K) activity. Overnight pretreatment of cells with lovastatin (20 microM) inhibits insulin stimulation of PI-3-K activity by 75%. Immunoprecipitation and immunoblotting experiments using antibodies against the regulatory subunit of PI-3-K (p85), phosphotyrosine, and insulin receptor alpha and beta subunits demonstrate that lovastatin inhibits the association of p85 with tyrosine phosphorylated insulin receptor substrate-1 and the beta subunit of the insulin receptor. Furthermore, lovastatin dramatically reduces (70-100%) the level of tyrosine phosphorylated insulin receptor beta subunit following insulin stimulation. These results clearly demonstrate that lovastatin disrupts early events of insulin mitogenic signaling by reducing the levels of tyrosine phosphorylated beta subunit and suggest that this disruption is a potential mechanism for the anti-mitogenic effect of lovastatin.     

Innovative multilayer antimicrobial films made with Nisaplin® or nisin and cellulosic ethers: Physico-chemical characterization,bioactivity and nisin desorption kinetics

In this study, ethylcellulose/hydroxypropylmethylcellulose/ethylcellulose (EC/HPMC/EC) three-layer films including Nisaplin® or nisin and lecithins were formulated. Lecithins were used as plasticizers to ensure cohesion between hydrophobic ethylcellulose and hydrophilic HPMC layers. It was observed that the introduction of pure nisin or its non-pure commercial form Nisaplin® into films didn't significantly alter their mechanical and optical properties. Additionally, these nisin or Nisaplin-loaded multilayer films showed significant antimicrobial activity. The comparison of inhibition diameters obtained with EC/HPMC film used as control and EC/HPMC/EC films demonstrated that the three-layer films delayed nisin desorption. This was confirmed by the kinetics of nisin release in a (0.8% w/v) NaCl solution at 28 °C: nisin from two-layer EC/HPMC films totally desorbed within 0.5 h, while the three-layer films allowed to expand nisin release time over 20 h. The ratio of nisin desorption coefficients (k_d): k_{d (EC/HPMC)}/k_{d (EC/HPMC/EC)} was determined after desorption modelling, and was found to be up to 118, proving that multilayer films with hydrophobic layers could be a potential way to control nisin release from antimicrobial bio-packagings.Industrial relevanceThis paper concerns active packaging, considered as a new approach to preserve food shelf life. Active packaging is a real gain for plastic and food industrials. Coating was used to obtain antimicrobial packaging. The impact of incorporating the antimicrobial agent in multilayer films on the release kinetics is investigated.     

Isolation and characterisation of lactic acid bacteria strains from raw camel milk for potential use in the production of fermented Tunisian dairy products

The aim of this work was to study the suitability of camel milk for the production of dairy products by lactic acid fermentation. Sixty strains of lactic acid bacteria (LAB) were isolated from camel milk. The strains were tested for their acidification activity, ability to use citrate, exopolysaccharide production, lipolytic, proteolytic activities and resistance to antibiotics. Ten strains were investigated for their ability to metabolize carbohydrates and that resulted in the identification of 5 Lactococcus lactis, 1 Lactobacillus pentosus, 2 Lactobacillus plantarum, 1 Lactobacillus brevis and 1 Pediococcus pentosaceus strains. Two strains of Lactococcus lactis SCC133 and SLch14 were selected to produce traditional Tunisian fermented dairy products (Lben, Raib, Jben cheese and Smen). These strains were chosen based on their acid production capacity and their ability to produce a high yield of biomass.     

Body orientation estimation with the ensemble of logistic regression classifiers

Multimedia Tools and Applications - Orientation of human body is an important feature that can be used for behavioral analysis in surveillance systems. This cue contains useful information such as...     

Improving asynchronous motor speed and flux loop control by using hybrid fuzzy-SMC controllers

This paper presents a new method combining sliding mode control (SMC) and fuzzy logic control (FLC) to enhance the robustness and performance for a class of non-linear control systems. This fuzzy sliding mode control (FSMC) is developed for application in the area for controlling the speed and flux loops of asynchronous motors. The proposed control law can solve those problems associated with the conventional control by sliding mode control, such as high current, flux and torque chattering, variable switching frequency and variation of parameters, in which a robust fuzzy logic controller replaces the discontinuous part of the classical sliding mode control law. Simulation results of the proposed FSMC technique on the speed and flux rotor controllers present good dynamic and steady-state performances compared to the classical SMC in terms of reduction of the torque chattering, quick dynamic torque response and robustness to disturbance and variation of parameters.