Spanish adaptation and validation of the Mobile Application Rating Scale questionnaire.

INTRODUCTION AND AIM: In recent years, numerous health-related apps have appeared on the market, and assessing their quality has become crucial. A very popular tool worldwide, created especially for this purpose, is the Mobile Application Rating Scale (MARS). However, there are no similar tools in Spanish. Therefore, the aim of this paper is to adapt MARS to the Spanish language and validate the resultant version. METHOD: The design consists of three processes: cross-cultural adaptation, translation, and metric evaluation. 46 mobile applications, 23 of which were for Apple telephones and 23 of which were for telephones running Android, were included in the study. The main objective of these applications was to promote physical activity. The internal factor structure and reliability of MARS were examined. RESULTS: No major differences were observed in the two Spanish translations, which were carried out independently. The blind back-translation, reviewed by the original author of MARS, suggested minor edits. Discrimination indices (item-scale correlation) obtained appropriate results for both raters. The reliability of the scores was found to be appropriate both in terms of internal consistency (α > 0.77), temporal stability (r > 0.72), and inter-rater reliability (IC > 0.76). The correlations between the subscales have shown high values with range between 0.47 and 0.83. CONCLUSION: The Spanish version of MARS was shown to have appropriate metric properties to assess the quality of health apps.

3D-RISM-KH molecular theory of solvation and density functional theory investigation of the role of water in the aggregation of model asphaltenes.

We applied a multiscale modeling approach that involves the statistical-mechanical three-dimensional reference interaction site model with the Kovalenko-Hirata closure approximation (3D-RISM-KH molecular theory of solvation) as well as density functional theory (DFT) of electronic structure to study the role of water in aggregation of the asphaltene model compound 4,4'-bis(2-pyren-1-yl-ethyl)-2,2'-bipyridine (PBP) [X. Tan, H. Fenniri and M. R. Gray, Energy Fuels, 2008, 22, 715]. The solvation free energy and potential of mean force predicted by 3D-RISM-KH reveal favorable pathways for disaggregation of PBP dimers in pure versus water-saturated chloroform solvent. The water density distribution functions elucidate hydrogen bonding preferences and water bridge formation between PBP monomers. The ΔG(298) values of -5 to -7 kcal mol(-1) for transfer of water molecules in chloroform to a state interacting with PBP molecules are in agreement with experimental results. Geometry optimization and thermochemistry analysis of PBP dimers with and without water bridges using WB97Xd/6-31G(d,p) predict that both PBP dimerization and dimer stabilization by water bridges are spontaneous (ΔG(298) < 0). The (1)H NMR chemical shifts of PBP monomers and dimers predicted using the gauge-independent atomic orbital method and polarizable continuum model for solvation in chloroform are in an excellent agreement with the experimental results for dilute and concentrated PBP solutions in chloroform, respectively [X. Tan, H. Fenniri and M. R. Gray, Energy Fuels, 2009, 23, 3687]. The DFT calculations of PBP dimers with explicit water show that bridges containing 1-3 water molecules lead to stabilization of PBP dimers. Additional water molecules form hydrogen bonds with these bridges and de-shield the PBP protons, negating the effect of water on the (1)H(C3) NMR chemical shift of PBP, in agreement with experiment. The ΔG(298) results show that hydrogen bonding to water and water-promoted polynuclear assembly bridging is as important as π-π interactions for asphaltene aggregation.