Distributed Proportional-spatial Derivative control of nonlinear parabolic systems via fuzzy PDE modeling approach

In this paper, a distributed fuzzy control design based on Proportional-spatial Derivative (P-sD) is proposed for the exponential stabilization of a class of nonlinear spatially distributed systems described by parabolic partial differential equations (PDEs). Initially, a Takagi-Sugeno (T-S) fuzzy parabolic PDE model is proposed to accurately represent the nonlinear parabolic PDE system. Then, based on the T-S fuzzy PDE model, a novel distributed fuzzy P-sD state feedback controller is developed by combining the PDE theory and the Lyapunov technique, such that the closed-loop PDE system is exponentially stable with a given decay rate. The sufficient condition on the existence of an exponentially stabilizing fuzzy controller is given in terms of a set of spatial differential linear matrix inequalities (SDLMIs). A recursive algorithm based on the finite-difference approximation and the linear matrix inequality (LMI) techniques is also provided to solve these SDLMIs. Finally, the developed design methodology is successfully applied to the feedback control of the Fitz-Hugh-Nagumo equation.     

Multipurpose modular experimental station for the DiProI beamline of Fermi@Elettra free electron laser

We present a compact modular apparatus with a flexible design that will be operated at the DiProI beamline of the Fermi@Elettra free electron laser (FEL) for performing static and time-resolved coherent diffraction imaging experiments, taking advantage of the full coherence and variable polarization of the short seeded FEL pulses. The apparatus has been assembled and the potential of the experimental setup is demonstrated by commissioning tests with coherent synchrotron radiation. This multipurpose experimental station will be open to general users after installation at the Fermi@Elettra free electron laser in 2011.     

A review on biological control and metabolism of aflatoxin

The series of events that led to the discovery of aflatoxin as a potent carcinogen, its biosynthesis, mechanism of action, structure-function relationship provide interesting insight into the economical and technological factors involved in the development of an effective control measure for the toxin. Scientists all over the world are making continuous efforts to explore a generalized process of detoxification, which can bring down the toxin content in heterogenous commodities to a threshold level. In this article biological control methods with special emphasis on in vivo and in vitro enzymatic detoxification of aflatoxin have been reviewed. Future areas of research involving large-scale enzymatic detoxification and modified atmosphere storage are also discussed.     

Use of a Shiga toxin (Stx)-enzyme-linked immunosorbent assay and immunoblot for detection and isolation of Stx-producing Escherichia coli from naturally contaminated beef

The purpose of this study was to evaluate an enzyme-linked immunosorbent assay (ELISA) and an immunoblot procedure for detection and isolation of Shiga toxin-producing Escherichia coli (STEC) from beef, and to correlate the presence of STEC in beef with E. coli and total coliform counts. A total of 120 samples of boneless beef supplied to a meat processor in southern Ontario were tested for the presence of STEC, E. coli, and total coliforms. Following enrichment in modified tryptic soy broth, samples were screened for Shiga toxin (Stx) by a Stx-ELISA and a Vero cell assay (VCA). Samples that were positive in the Stx-ELISA were subjected to the Stx-immunoblot for STEC isolation. Overall, 33.3% of samples were positive in the VCA, and 34.2% were positive in the Stx-ELISA. There was almost complete agreement between the Stx-ELISA and the VCA results (kappa = 0.98). The sensitivity and specificity of the Stx-ELISA with respect to the VCA were 100% and 98.75%, respectively. STEC were isolated by the Stx-immunoblot from 87.8% of the samples that were positive in the Stx-ELISA. The STEC isolates belonged to 19 serotypes, with serotype O113:H21 accounting for 10 of 41 isolates. No STEC of serotype O157:H7 were isolated. There was a significant correlation between E. coli counts and total coliform counts (Spearman correlation coefficient = 0.68, P < 0.01). The E. coli count was positively correlated with detection of STEC by both the Stx-ELISA and the VCA (P < 0.01).     

Amphiphilic Interpenetrating Networks for the Delivery of Hydrophobic, Low Molecular Weight Therapeutic Agents

To investigate the delivery of hydrophobic therapeutic agents, a novel class of interpenetrating networks (IPNs) were synthesized and composed of two networks: methacrylic acid grafted with poly(ethylene glycol) tethers, P(MAA-g-EG), and poly(n-butyl acrylate) (PBA). The hydrophilic P(MAA-g-EG) networks are pH-responsive hydrogels capable of triggered release of an encapsulated therapeutic agent, such as a low molecular weight drug or a protein, when it passes from the stomach (low pH) to upper small intestine (neutral pH). PBA is a hydrophobic homopolymer that can affect the IPN swelling behavior, the therapeutic agent loading efficiencies in IPNs, and solute release profiles from IPNs. In dynamic swelling conditions, IPNs had greater swelling ratios than P(MAA-g-EG), but in equilibrium swelling conditions the IPN swelling ratio decreased with increasing PBA content. Loading efficiencies of the model therapeutic agent fluorescein ranged from 21 - 44%. Release studies from neat P(MAA-g-EG) and the ensuing IPNs indicated that the transition from low pH (2.0) to neutral pH (7.0) triggered fluorescein release. Maximum fluorescein release depended on the structure and hydrophilicity of the carriers used in these studies.     

武装你的笔记本电脑

当你新购买一台本本(笔记本电脑昵称),你一定非常高兴吧,笔者当时就是这样的心情。但是光有本本总是感觉缺少了什么。既然有了自己心爱的东东就要好好爱护,为你的本本添加一些实用的外设也是非常必要的,今天我就来谈谈如何把本本“武装起来”。 好插座当然不可少 电源是一件需要高度重视的问题,如果你的宝贝本本在电源上出了问题,那再痛苦不过了,所以要对你的电源倍     

Electrogenerated chemiluminescence from tris(2,2'-bipyridyl)ruthenium(II) immobilized in titania-perfluorosulfonated ionomer composite films

Electrochemical behavior and electrogenerated chemiluminescence (ECL) of tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)3(2+)) immobilized in sol-gel-derived titania TiO2)-Nafion composite films coated on a glassy carbon electrode have been investigated. The electroactivity of Ru(bpy)3(2+) ion exchanged into the composite films and its ECL behavior were strongly dependent upon the amount of Nafion incorporated into the TiO2-Nafion composite films. The ECL sensor of Ru(bpy)32+ immobilized in a TiO2-Nafion composite with 50% Nafion content showed the maximum ECL intensities for both tripropylamine (TPA) and sodium oxalate in 0.05 M phosphate buffer solution at pH 7. Detection limits were 0.1 microM for TPA and 1.0 microM for oxalate (S/N = 3) with a linear range of 3 orders of magnitude in concentration. The present ECL sensor showed improved ECL sensitivity and long-term stability, as compared to the ECL sensors based on pure Nafion films. The present Ru(bpy)3(2+) ECL sensor based on TiO2-Nafion (50%) composite films was applied as an HPLC detector for the determination of erythromycin in human urine samples. The present Ru(bpy)3(2+) ECL sensor was stable in the mobile phase containing a high content of organic solvent (30%, v/v), in contrast to a pure Nafion-based Ru(bpy)3(2+) ECL sensor. The detection limit for erythromycin was 1.0 microM, with a linear range of 3 orders of magnitude in concentration.