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[EN] The study of oxygen consumption rate under¿ in vivo¿ human cornea during contact lens wear has been technically a challenge and several attempts have been made in the last 20 years to model the physiology of the human cornea during contact lens wear. Unfortunately, some of these models, based on a constant corneal oxygen consumption rate, produce areas on the cornea where the oxygen tension is negative, which has no physical sense. In order to avoid such inconsistency, different researchers have developed alternative models of oxygen consumption, which predict the likely oxygen metrics available at the interface cornea/post lens tear film by determination of oxygen flux, oxygen consumption, and oxygen tension through the different layers (endothelium, stroma, and epithelium). Although oxygen deficiency produces corneal edema, corneal swelling, hypoxia, acidosis, and other abnormalities, the estimation of the oxygen distribution below the impact of a contact lens wear is interesting to know which lens transmissibility was adequate to maintain the cornea and avoid epithelial and stromal anoxia. The estimation of minimum transmissibility for a lens for extended wear applications will be very useful for both clinicians and manufacturers. The aim of this work is to present a complete discussion based on Monod kinetics model that permits give an estimation of oxygen partial pressure distribution, the profile distribution of corneal flux and oxygen consumption rate, and finally the estimation of the relaxation mechanism of the cornea depending on the oxygen tension at the interface cornea/post lens tear film. Relaxation time in this context can quantify the capability of the corneal tissue to adapt to increasing concentrations of oxygen. It is proposed this parameter as a biological meaningful indicator of the interaction between contact lens polymers and living tissues such as the corneal cellular layer. ; This work was supported by the Government of Spain (project no. PID2019-108434GB-100 AEI/FEDER,UE), and ...

92 4 ; S ; The dielectric and mechanical spectroscopies of acetate of cis- and trans-2-phenyl-5-hydroxymethyl-1,3- dioxane are reported in the frequency domain from 10−2 to 106 Hz. This ester has been selected in this study for its predominant á relaxation with regard to the â relaxation, which can be neglected. This study consists of determining an interconversion algorithm between dielectric and mechanical measurements, given by using a relation between rotational and translational complex viscosities. These important viscosities were obtained from measures of the dielectric complex permittivity and by dynamic mechanical analysis, respectively. The definitions of rotational and translational viscosities were evaluated by means of fractional calculus, by using the fit parameters of theHavriliak-Negami empirical model obtained in the dielectric and mechanical characterization of the á relaxation. This interconversion algorithm is a generalization of the break of the Stokes-Einstein-Debye relationship. It uses a power law with an exponent defined as the shape factor, which modifies the translational viscosity. Two others factors are introduced for the interconversion, a shift factor, which displaces the translational viscosity in the frequency domain, and a scale factor, which makes equal values of the two viscosities. In this paper, the shape factor has been identified as the relation between the slopes of the moduli of the complex viscosities at higher frequency. This is interpreted as the degree of kinetic coupling between the molecular rotation and translational movements. Alternatively, another interconversion algorithm has been expressed by means of dielectric and mechanical moduli. The authors thank Professor Niels Boye Olsen and Jeppe C. Dyre from Roskilde Universitetcenter (Denmark) for dielectric and mechanical measurements. This work was supported by DGAPA-UNAM Projects No. IG-100315, SEP-CONACYT 154626, M.J.S. gratefully acknowledge the CICYT for grant MAT2012-3383. Garcia Bernabe, A.; Lidon-Roger, ...

7624 7635 16 32 ; S Steele, B. C. H., & Heinzel, A. (2001). Materials for fuel-cell technologies. Nature, 414(6861), 345-352. doi:10.1038/35104620 ; Escorihuela, J., García-Bernabé, A., Montero, Á., Sahuquillo, Ó., Giménez, E., & Compañ, V. (2019). Ionic Liquid Composite Polybenzimidazol Membranes for High Temperature PEMFC Applications. Polymers, 11(4), 732. doi:10.3390/polym11040732 ; [EN] In this paper, a series of composite proton exchange membranes comprising a cobaltacarborane protonated H[Co(C2B9H11)(2)] named (H[COSANE]) and polybenzimidazole (PBI) for a high temperature proton exchange membrane fuel cell (PEMFC) is reported, with the aim of enhancing the proton conductivity of PBI membranes doped with phosphoric acid. The effects of the anion [Co(C2B9H11)(2)] concentration in three different polymeric matrices based on the PBI structure, poly(2,2 '-(m-phenylene)-5,5 '-bibenzimidazole) (PBI-1), poly[2,2 '-(p-oxydiphenylene)-5,5 '-bibenzimidazole] (PBI-2) and poly(2,2 '-(p-hexafluoroisopropylidene)-5,5 '-bibenzimidazole) (PBI-3), have been investigated. The conductivity, diffusivity and mobility are greater in the composite membrane poly(2,2 '-(p-hexafluoroisopropylidene)-5,5 '-bibenzimidazole) containing fluorinated groups, reaching a maximum when the amount of H[COSANE] was 15%. In general, all the prepared membranes displayed excellent and tunable properties as conducting materials, with conductivities higher than 0.03 S cm(-1)above 140 degrees C. From an analysis of electrode polarization (EP) the proton diffusion coefficients and mobility have been calculated. This work was financially supported by the Ministerio de Economia y Competitividad (MINECO) under project ENE/2015-69203-R and by Consejo Nacional de Ciencia y Tecnologia (CONACyT) for the postdoctoral grant to J. O. The technical support of Servei de Microscpia Electrnica at Universitat Politecnica de Valencia and Servei Central d'Instrumentacio Cientifica at Universitat Jaume I is gratefully acknowledged. The authors thanks Prof. ...