Applicability of the user engagement scale to mobile health : a survey-based quantitative study

Background: There has recently been exponential growth in the development and use of health apps on mobile phones. As with most mobile apps, however, the majority of users abandon them quickly and after minimal use. One of the most critical factors for the success of a health app is how to support users’ commitment to their health. Despite increased interest from researchers in mobile health, few studies have examined the measurement of user engagement with health apps. Objective: User engagement is a multidimensional, complex phenomenon. The aim of this study was to understand the concept of user engagement and, in particular, to demonstrate the applicability of a user engagement scale (UES) to mobile health apps. Methods: To determine the measurability of user engagement in a mobile health context, a UES was employed, which is a psychometric tool to measure user engagement with a digital system. This was adapted to Ada, developed by Ada Health, an artificial intelligence–powered personalized health guide that helps people understand their health. A principal component analysis (PCA) with varimax rotation was conducted on 30 items. In addition, sum scores as means of each subscale were calculated. Results: Survey data from 73 Ada users were analyzed. PCA was determined to be suitable, as verified by the sampling adequacy of Kaiser-Meyer-Olkin=0.858, a significant Bartlett test of sphericity (χ2300=1127.1; P<.001), and communalities mostly within the 0.7 range. Although 5 items had to be removed because of low factor loadings, the results of the remaining 25 items revealed 4 attributes: perceived usability, aesthetic appeal, reward, and focused attention. Ada users showed the highest engagement level with perceived usability, with a value of 294, followed by aesthetic appeal, reward, and focused attention. Conclusions: Although the UES was deployed in German and adapted to another digital domain, PCA yielded consistent subscales and a 4-factor structure. This indicates that user engagement with health apps can be assessed with the German version of the UES. These results can benefit related mobile health app engagement research and may be of importance to marketers and app developers

Dibenzo[a,g]quinolizin-8-ones: synthesis, estrogen receptor affinities, and cytostatic activity

A number of acetoxy-substituted dibenzo[a,g]quinolizin-8-ones were synthesized by the reaction of 1-oxoisoquinolines with substituted homophthalic acid anhydride. All of the derivatives with acetoxy groups in positions 3 and 10 bind to the estrogen receptor. Relative binding affinities (RBA) ranged from 1.8 to 5.6 (estradiol: RBA = 100) when the substituent at C-6 was a short alkyl group. Introduction of additional oxygen functions in the 2- and/or 11-position decreased binding affinities. Analyses of the enantiomers of 6-methyl (6b) and 6-ethyl (6c) derivatives revealed that the receptor binding is mainly due to one optical isomer (e.g. (-)-6b, 9.9; (+)-6b, 0.6). In hormone-sensitive human MCF-7 breast cancer cells, compounds with one acetoxy group in each aromatic ring strongly inhibited cellular growth. Despite marked differences in receptor affinity, the enantiomers displayed similar activities in this cell culture. In hormone-independent MDA-MB 231 mammary tumor cells, only a weak cytostatic effect was recorded at 10-5 M. In the immature mouse uterine weight test, minimal estrogenic activity was observed. At higher doses, a significant anti-estrogenic effect became evident. It is assumed that the estrogen antagonism is responsible for the specific cytostatic effect in MCF-7 breast cancer cells

Development of an annoyance model based upon elementary auditory sensations for steady-state aircraft interior noise containing tonal components

The purpose of this investigation was to develop a noise annoyance model, superior to those already in use, for evaluating passenger response to sounds containing tonal components which may be heard within current and future commercial aircraft. The sound spectra investigated ranged from those being experienced by passengers on board turbofan powered aircraft now in service to those cabin noise spectra passengers may experience within advanced propeller-driven aircraft of the future. A total of 240 sounds were tested in this experiment. Sixty-six of these 240 sounds were steady state, while the other 174 varied temporally due to tonal beating. Here, the entire experiment is described, but the analysis is limited to those responses elicited by the 66 steady-state sounds