Preparative isoelectric focusing in multicompartment electrolyzers: novel, hydrolytically stable and hydrophilic isoelectric membranes

Preparative isoelectric focusing in multicompartment electrolyzers is based on the production of isoelectric membranes of precise isoelectric point, able to buffer at their pI value and to titrate proteins tangent to or crossing the membranes. Up to the present, such membranes have been based on polyacrylamide chemistry; acrylamide, however, is neither stable in acidic nor basic environments. We describe here novel membranes, produced with a unique monomer, N-acryloylaminoethoxyethanol (AAEE). Poly(AAEE) membranes are extremely stable to alkaline hydrolysis (500 times more stable than polyacrylamide) and even more hydrophilic than the latter matrix. This allows production of highly reproducible membranes (these do not change their pI with time, since no acrylic acid is produced by hydrolysis upon storage) which do not adsorb proteins by hydrophobic interaction.     

Human globin chain separation by capillary electrophoresis in acidic isoelectric buffers

The potency of a series of anticholinesterase (anti-ChE) agents and serotonin-related amines as inhibitors of the aryl acylamidase (AAA) activity associated with electric eel acetylcholinesterase (AChE) (EC 3.1.1.7) and horse serum butyrylcholinesterase (BuChE) (EC 3.1.1.8) was examined and compared with the potency of the same compounds as ChE inhibitors. Neostigmine, physostigmine, BW 284C51, (+/-)-huperzine A, E2020, tacrine, edrophonium and heptyl-physostigmine were, in that order, the most potent in inhibiting eel AChE-associated AAA activity, their inhibitor constant (Ki) values being in the range 0.02-0.37 microM. The rank order of the same compounds as AChE inhibitors basically paralleled that of AAA, although they were in general stronger on AChE (Ki = 0.001-0.05). The peripheral anionic site inhibitors propidium and gallamine were inactive on AChE-associated AAA. Serotonin and its derivatives were slightly stronger on AAA (Ki = 7.5-30 microM) than on AChE (Ki = 20-140 microM). Tacrine (IC50 = 0.03 microM), diisopropylfluorophosphate (IC50 = 0.04 microM), heptyl-physostigmine (IC50 = 0.11 microM), physostigmine (IC50 = 0.15 microM) and tetra-iso-propylpyrophosphoramide (iso-OMPA) (IC50 = 0.75 microM) were the most potent in inhibiting horse serum BuChE-associated AAA activity. Serotonin and related amines were very weak on BuChE-associated AAA activity. These results indicate that the inhibitory potencies of the active site anti-ChE agents on the AAA activity associated with eel AChE and horse serum BuChE are closely correlated with their action on the respective ChE. In addition, the efficacy of tacrine, E2020, heptyl-physostigmine and (+/-)-huperzine A in the treatment of Alzheimer's disease is unlikely to be related to the action of these drugs on ChE-associated AAA.     

Adsorption of block copolymers at latex surface and their utilization in emulsion polymerization

Amphiphilic block copolymers have been investigated for their utilization in emulsion polymerization of butyl methacrylate. Special attention has been paid to the adsorption mechanism of the block copolymers from systematic measurements of equilibrium adsorption isotherms. A series of well-defined water-soluble amphiphilic block copolymers, composed of poly(butyl methacrylate) and poly(sodium methacrylate) blocks, were synthesized by anionic polymerization of butyl methacrylate and tert-butyl methacrylate followed by the thermal deprotection of the tert-butyl ester groups and final hydrolysis. The number density of emulsion polymer particles N_P varied as [copolymer]^α, α lying between 0.44 and 0.73 according to the hydrophilic content of the copolymers. In contrast with SDS taken as a reference emulsifier, the adsorption of the copolymers was very strong and this provided quite an efficient stabilization of the polymer particles during emulsion polymerization, even at low concentrations (<10⁻⁴ mol L⁻¹) and low coverages (<10% of the interfacial area).     

Handling causality and schedulability when designing and prototyping cyber-physical systems

Software and Systems Modeling - Cyber physical systems are built upon digital and analog circuits, making it necessary to handle different models of computation during their design and verification...     

A minimum Hellinger distance estimator for stochastic differential equations: An application to statistical inference for continuous time interest rate models

A minimum disparity estimator minimizes a φ-divergence between the marginal density of a parametric model and its non-parametric estimate. This principle is applied to the estimation of stochastic differential equation models, choosing the Hellinger distance as particular φ-divergence. Under an hypothesis of stationarity, the parametric marginal density is provided by solving the Kolmogorov forward equation. A particular emphasis is put on the non-parametric estimation of the sample marginal density which has to take into account sample dependence and kurtosis. A new window size determination is provided. The classical estimator is presented alternatively as a distance minimizer and as a pseudo-likelihood maximizer. The latter presentation opens the way to Bayesian inference. The method is applied to continuous time models of the interest rate. In particular, various models are tested using alternatively tests and their results are discussed.     

Real‐time updating of structural mechanics models using Kalman filtering,modified constitutive relation error,and proper generalized decomposition

The paper aims at proposing a new strategy for real‐time identification or updating of structural mechanics models defined as dynamical systems. The main idea is to introduce the modified constitutive relation error concept, which is a practical tool that enables to efficiently solve identification problems with highly corrupted data, into the Kalman filtering, which is a classical framework for data assimilation. Furthermore, a PGD‐based model reduction method is performed in order to optimize capabilities of the online updating strategy. Performances of the proposed approach, in terms of robustness gain and computational cost reduction, are illustrated on several unsteady thermal applications. Copyright © 2015 John Wiley & Sons, Ltd.     

Photocatalytic degradation of a phenylurea, chlortoluron, in water using an industrial titanium dioxide coated media

The degradation of an herbicide, chlortoluron, by UV/TiO₂ photocatalysis in water using industrial titanium dioxide coated non-woven paper was studied. The influence of parameters such as adsorption capacity, initial concentration and TiO₂ implementation (coated or in suspension) was investigated. The results emphasize the importance of operational conditions and reactor geometry on the kinetic degradation rate. The analysis of the first organic by-products suggests that a hydroxyl radical attack occurs on the phenyl ring and methyl groups of the chlortoluron before the opening of the aromatic ring. The fate of hetero-atoms has been investigated. The fates of the two nitrogen atoms in the molecule are different, not only did it depend on their initial oxidation degree, as both had the same oxidation degree, but also on the initial oxidation state of neighboring carbons. The chlorine atoms were completely released as chloride ions. The study of the influence of the oxygen concentration showed the importance of the oxygen mass transfer when designing an industrial photocatalytic reactor. An original calculation process was carried out to evaluate the adsorption constant of oxygen over the whole photocatalysis period and not only in the initial conditions as previously provided. This work points out the necessity of extending the understanding of the efficiency of chlortoluron removal or of the removal of various complex pesticide mixtures found in agricultural wastewater, using alternative, more industrially realistic, reactors.     

Nonlinear adaptive control for bioreactors with unknown kinetics

We consider a control problem for a single bioreaction occurring in a continuous and well-mixed bioreactor, assuming that the bioreaction's kinetics is not represented by a validated model. We develop a nonlinear controller and prove the global asymptotic stability of the closed-loop system towards the equilibrium corresponding to the set point. Since this control law needs the knowledge of some parameters, we derive an adaptive version of the nonlinear controller and prove again the global asymptotic stability of the closed-loop system. Finally, we show the relevance of our approach on a real-life wastewater treatment plant.     

Ligand‐Free Synthesis of Aluminum‐Doped Zinc Oxide Nanocrystals and their Use as Optical Spacers in Color‐Tuned Highly Efficient Organic Solar Cells

The color of polymer solar cells using an opaque electrode is given by the reflected light, which depends on the composition and thickness of each layer of the device. Metal‐oxide‐based optical spacers are intensively studied in polymer solar cells aiming to optimize the light absorption. However, the low conductivity of materials such as ZnO and TiO₂ limits the thickness of such optical spacers to tenths of nanometers. A novel synthesis route of cluster‐free Al‐doped ZnO (AZO) nanocrystals (NCs) is presented for solution processing of highly conductive layers without the need of temperature annealing, including thick optical spacers on top of polymer blends. The processing of 80 nm thick optical spacers based on AZO nanocrystal solutions on top of 200 nm thick polymer blend layer is demonstrated leading to improved photocurrent density of 17% compared to solar cells using standard active layers of 90 nm in combination with thin ZnO‐based optical spacers. These AZO NCs also open new opportunities for the processing of high‐efficiency color tuned solar cells. For the first time, it is shown that applying solution‐processed thick optical spacer with polymer blends of different thicknesses can process solar cells of similar efficiency over 7% but of different colors.