Metric differentiability of Lipschitz maps defined on Wiener spaces

This note is devoted to the differentiability properties of -Lipschitz maps defined on abstract Wiener spaces and with values in metric spaces (Y,d _Y ). We prove the existence γ-a.e. of local seminorms in the Cameron-Martin space which allow to compute the metric derivative of the map. Second Author partially supported by DGES (Spain) MTM2006-03531.     

Synthesis of polyaniline and application in the design of formulations of conductive paints

Polyaniline (PANI) is prepared by chemical polymerization of aniline in acidic medium using ammonium peroxydisulfate ((NH₄)₂S₂O₈) as oxidant. The polymer, with a conductivity of 25–30 S/cm, is used to formulate conducting paints. A stable paint with a conductivity of 10^?3 S/cm is obtained. Copyright © 2004 John Wiley & Sons, Ltd.     

Synthesis and characterization of new polymeric ionic liquid microgels

A new two‐step route toward the synthesis of polymeric ionic liquid microgel particles is presented. In the first step, hydrophilic microparticles were prepared by the concentrated emulsion polymerization of the ionic liquid 1‐vinyl‐3‐ethylimidazolium bromide in the presence of small amounts of N,N‐dimethylenebisacrylamide as a crosslinking agent. In the second step, the bromide anion was exchanged in water with different anions such as BF, CF₃SO, (CF₃SO₂)₂N^?, (CF₃CF₂SO₂)₂N^?, and dodecylbenzenesulfonate, and this resulted in the coagulation of the microparticles, which were easily recovered by filtration. The obtained polymeric ionic liquid microparticles could be swollen in a very broad range of organic solvents, including apolar organic solvents. As an application, glucose oxidase was encapsulated inside polymeric ionic liquid microparticles, which were used in an amperometric biosensor. The response of the biosensor showed excellent values that strongly depended on the nature of the polymeric ionic liquid counteranion in the order of Br^? > BF > (CF₃SO₂)₂N^?. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3958–3965, 2006     

Assembled cation‐exchange/anion‐exchange polypyrrole layers as new simplified artificial muscles

A simplified artificial muscle has been constructed by assembling different polypyrrole structures in the same synthesis process. This produces not only “all‐polymeric” but rather a new generation of “all‐conducting‐polymer” artificial muscles, capable of moving in electrolytic media by an electrical current application with no evidence of delamination after several cycles. Suitable devices can be constructed for biomedical applications, based on this conducting polymer film. Copyright © 2006 John Wiley & Sons, Ltd.     

p-Poincaré inequality versus ∞-Poincaré inequality: some counterexamples

We point out some of the differences between the consequences of p-Poincaré inequality and that of ∞-Poincaré inequality in the setting of doubling metric measure spaces. Based on the geometric characterization of ∞-Poincaré inequality given in Durand-Cartagena et al. (Mich Math J 60, 2011), we obtain a geometric property implied by the support of a p-Poincaré inequality, and demonstrate by examples that an analogous geometric characterization for finite p is not possible. The examples we give are metric measure spaces which are doubling and support an ∞-Poincaré inequality, but support no finite p-Poincaré inequality. In particular, these examples show that one cannot expect a self-improving property for ∞-Poincaré inequality in the spirit of Keith–Zhong (Ann Math 167(2):575–599, 2008). We also show that the persistence of Poincaré inequality under measured Gromov–Hausdorff limits fails for ∞-Poincaré inequality.     

Cooperative use of cytochrome cd1 nitrite reductase and its redox partner cytochrome c552 to improve the selectivity of nitrite biosensing

In this work, a novel enzymatic biosensor for determination of nitrites constructed on an electrochemical transducing platform is proposed. The sensor is based on cytochrome-cd(1) (cyt-cd(1)) nitrite reductase from Marinobacter hydrocarbonoclasticus strain 617 as biological recognition element, and its putative physiological redox partner cytochrome-c(552) (cyt-c(552)), as electron mediator. The proteins were co-immobilized using a photopolymerizable polyvinyl alcohol (PVA) derivative, onto carbon paste screen printed electrodes (CPSPEs); the optimal modification conditions were 100 μM cyt-cd(1)/100 μM cyt-c(552) and 50% PVA, after a 48 h polymerization time. Electrochemical characterization of the mediator was carried out by cyclic voltammetry. The one-electron exchange between cyt-c(552) and the working electrode is a quasi-reversible process, without mass transport limitations. The formal potential of the mediator is 254±2 mV vs NHE and the intermolecular electron transfer rate constant between cytochromes c(552) and cd(1) is 9.9×10(3)M(-1)s(-1). The analytical parameters of the biosensor response to nitrite as assessed by amperometric measurements were: linear range from 10 to 200 μM; detection and quantification limits of 7 and 24 μM, respectively; sensitivity of 2.49±0.08 Amol(-1)cm(2) μM(-1). Catalytic profiles in the presence of possible interfering species were also investigated. The interference from competitive enzymatic reduction of dissolved oxygen could be overcome by tuning the cyclic voltammograms for faster sweep rates.     

Self-contracted curves in Riemannian manifolds

It is established that every self-contracted curve in a Riemannian manifold has finite length, provided its image is contained in a compact set.     

Conductivity enhancement in raw polypyrrole and polypyrrole nanoparticle dispersions

For certain commercial applications of polypyrrole (PPy), an enhancement of the electrical conductivity of the material is the key to industrial success. In this paper it will be shown that raw PPy with high conductivity (>150 S/cm) can be obtained in very good yield (>90%) by appropriate selection of both bi‐functional additives and reaction conditions which increase the oxidative polymerization rate of pyrrole. The presence of new active centers for the polymerization is demonstrated by UV measurements. In addition, raw PPy synthesized according to the improved method of synthesis shows good stability of the conductivity upon aging at high temperature (150°C) in air. Finally, new PPy dispersions are reported with an average particle size of 67 nm obtained by sonochemical synthesis that can be incorporated into conventional plastic paints for direct metallization of plastics. The conductivity of the new metallization paint developed was 0.4 S/cm with a PPy content of 10 wt%. Copyright © 2006 John Wiley & Sons, Ltd.