Functional electrical stimulation by nanogenerator with 58 V output voltage

We demonstrate a new type of integrated nanogenerator based on arrays of vertically aligned piezoelectric ZnO nanowires. The peak open-circuit voltage and short-circuit current reach a record high level of 58 V and 134 μA, respectively, with a maximum power density of 0.78 W/cm(3). The electric output was directly applied to a sciatic nerve of a frog, inducing innervation of the nerve. Vibrant contraction of the frog's gastrocnemius muscle is observed as a result of the instantaneous electric input from the nanogenerator.     

Continuous and multidimensional assessment of resilience based on functionality analysis for interconnected systems

The increasing number of disruptions to critical infrastructure, like natural disasters, terrorist attacks or internal failure is today a major problem of society. Concern is even greater when considering the interconnected nature of critical infrastructure, which might lead to failure propagation, causing domino and cascade effects. To mitigate such outcomes, critical infrastructure must recover its capacity to function with regard to several criteria. Stakeholders must therefore analyse and improve the resilience of critical infrastructure before any disruption occurs, and base this analysis on different models so as to guarantee society’s vital needs. Current resilience assessment methods are mainly oriented toward the context of a single system, thus narrowing their criteria metrics, limiting flexibility and adaptation to other contexts and overlooking the interconnected nature of systems. This article introduces a new tool-equipped approach that makes it possible to define a model to evaluate the functionalities of interconnected systems. The model is then used to assess the resilience of these systems based on simple and generic criteria that can be extended and adapted. Several assertions related to the concept of resilience and some resilience indicators are also introduced. A case study provides the validation performed by experts from several domains.     

Synthesis and dispersion copolymerization of poly(2‐methyl‐2‐oxazoline) macromers with cinnamoyl end groups

Poly(2‐methyl‐2‐oxazoline) (PMOZO) macromers bearing cinnamoyl functional groups were synthesized either by utilizing the end‐capping method of growing PMOZO living chains with cinnamic acid or by coupling glycolic PMOZO telomers with cinnamoyl chloride. The first approach was proved to be more efficient and convenient, giving rise easier to a quantitative functionalization. Dispersion copolymerization of styrene with the resulted macromers in an ethanol–water system has been studied in order to obtain monodisperse micrometer size beads. The effect of some variables, such as macromer dimension and concentration, initiator type, alcohol/water ratio, on conversion, particle size and size distribution was investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2191–2199, 2001     

Biocidal activity of cellulose materials for medical implants

Surface wettability trends, and blood component adhesion of some cellulose acetate phthalate/hydroxypropyl cellulose blend films are analyzed in view of adapting the system to biomedical applications. The results show that intermediate blend compositions of the corresponding films influence the surface tension parameters—controlled by the interactions occurring in the system. Increasing hydrophobicity and, implicitly, decreasing the polar surface tension components, are correlated with the adhesion/cohesion of blood components and plasma proteins. Thus, the work of spreading proteins on the hydrophobic blend surfaces indicated that albumin is not absorbed preferentially, while fibrinogen is characterized by a higher degree of adhesion on the surfaces, and also that selective adsorption of plasma proteins modifies blood compatibility. In addition, the obtained results and the ascertained antimicrobial activity of the studied blends contribute to the development of new applications in the biomedical field. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41932     

Surface characterization of quaternized polysulfone films and biocompatibility studies

A novel quaternized polysulfone with N‐dimethyloctylammonium groups was investigated with respect to its surface properties, hydrophobicity, interactions with blood, and morphology. The history of the films formed from N,N‐dimethylformamide/methanol and N,N‐dimethylformamide/water solutions and the compositions of the solvent/nonsolvent mixtures influenced the surface morphology. Thus, atomic force microscopy investigations of the films showed pores and nodules of different sizes and intensities, which depended on the content of methanol or water in the solvent mixtures. Hydrophilicity modification, evidenced by the apolar components and the electron‐acceptor and electron‐donor parameters of the polar components of the surface tension parameters, was correlated with atomic force microscopy data. Surface wettability trends were analyzed on the basis of the free energy of hydration between the prepared films and water and the work of adhesion. The adhesion of red blood cells to the modified polysulfone showed the influence of the hydrophobic properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Relationships between the synthesis conditions and the characteristics of anion exchangers

Several macroporous styrene–divinylbenzene copolymers were prepared using different diluents. The copolymers were chloromethylated with monochlor methyl ether and aminated with N,N-dimethyl-2-hydroxyethylamine in order to perform strongly basic anion exchanger, type II. It was established that the network morphology of anion exchanger determines its ion-exchange rate. It was, also established, by means of transmission electron microscopy, that chloromethylation reaction led to the morphological changes in the macromolecular network of the copolymers.