Abstract. Mobile health is an emerging field which is attracting much attention. Nevertheless, tools for the development of mobile health applications are lacking. This work presents mHealthDroid, an open source Android implementation of a mHealth Framework designed to facilitate the rapid and easy development of biomedical apps. The framework is devised to leverage the potential of mobile devices like smartphones or tablets, wearable sensors and portable biomedical devices. The framework provides functionalities for resource and communication abstraction, biomedical data acquisition, health knowledge extraction, persistent data storage, adaptive visualization, system management and value-added services such as intelligent alerts, recommendations and guidelines.

The delivery of healthcare services has experienced tremendous changes during the last years. Mobile health or mHealth is a key engine of advance in the forefront of this revolution. Although there exists a growing development of mobile health applications, there is a lack of tools specifically devised for their implementation. This work presents mHealthDroid, an open source Android implementation of a mHealth Framework designed to facilitate the rapid and easy development of mHealth and biomedical apps. The framework is particularly planned to leverage the potential of mobile devices such as smartphones or tablets, wearable sensors and portable biomedical systems. These devices are increasingly used for the monitoring and delivery of personal health care and wellbeing. The framework implements several functionalities to support resource and communication abstraction, biomedical data acquisition, health knowledge extraction, persistent data storage, adaptive visualization, system management and value-added services such as intelligent alerts, recommendations and guidelines. An exemplary application is also presented along this work to demonstrate the potential of mHealthDroid. This app is used to investigate on the analysis of human behavior, which is considered to be one of the most prominent areas in mHealth. An accurate activity recognition model is developed and successfully validated in both offline and online conditions.

It is important to understand how interfacial composition influences the digestion of coated interfaces in order to rationally design emulsion based food products with specific digestion profiles. This study has been designed to investigate the effects of gastrointestinal digestion on protein covered interfaces. In this work, we have used a new apparatus fully designed and assembled at the University of Granada: the OCTOPUS. This new device enables the design of a customised static sequential in vitro digestion process in a single droplet. Physiological conditions of each compartment/step of the digestion process are met through subphase exchange of artificial digestive media, hence mimicking the transit through the gastrointestinal tract. We can measure in situ the evolution of the interfacial tension throughout the whole simulated gastrointestinal transit and the mechanical properties of the interfacial layer (interfacial dilatational modulus) after each digestion stage (mouth, stomach, small intestines). The in vitro digestion model used here focuses on pepsinolysis and lipolysis of two dairy proteins: b-lactoglobulin (BLG) and b-casein (BCS) adsorbed at the olive oil-water interface. The results show different susceptibilities of interfacial layers of BLG and BCS to pepsinolysis; while pepsinolysis of adsorbed BLG weakens the interfacial network, pepsinolysis of adsorbed BCS strengthens it as measured by the dilatational moduli. These numbers provide an interfacial scenario for previous findings on emulsification of these proteins, which was found to improve BLG pepsinolysis but somehow protected BCS from pepsinolysis in the stomach. The desorption profiles provide quantification of the extent of lipid digestion in subsequent simulated intestinal fluid containing lipase. The extent of lipid hydrolysis was found to be similar in BLG and BCS covered interfaces and comparable to that in the absence of coverage (pure oil-water interface) indicating that proteins do not comprise a barrier to lipolysis. This similar susceptibility is attributed to the similar interfacial properties of the interfaces reaching the duodenum despite the structural differences between native BCS and BLG, thus demonstrating the impact of the transit through the gut on lipolysis. This research allows identification of the interfacial mechanisms affecting enzymatic hydrolysis of proteins and lipolysis. The results can be exploited in tailoring novel food matrices with improved functional properties such as decreased digestibility, controlled energy intake and low allergenicity.

A new Langmuir-type pendant-drop penetration film balance has been developed combining a Langmuir-type pendant-drop film balance with a new rapid-subphase-exchange technique. In addition to the determination of surface pressure—molecular area isotherms of insoluble monolayers deposited on the surface of a pendant drop, it allows the study of reactions with some surfactant added to the subphase. The monolayer is spread on the surface of a drop suspended from a capillary, which is the outer one of an arrangement of two coaxial capillaries connected to the different branches of a microinjector. Once the film is brought to the desired state of compression by varying the drop volume with the microinjector, the subphase liquid in the drop can be exchanged quantitatively by means of the coaxial capillaries. This exchange is complete for a through-flow of at least three times the drop volume, and the monolayers endure it at all tested film pressures. The determination of surface tension as a function of surface area is performed using axisymmetric drop shape analysis (ADSA). The complete set-up, i.e., the image capturing and microinjector system is fully computer controlled by a user-friendly and fully Windows integrated program, including the ADSA surface tension calculus algorithm. As a penetration film balance, pendant-drop methodologies offer a wide range of advantages such as a more stringent control of the environmental conditions and therefore, more uniform temperature, pressure and concentration along the interface, small amounts of material needed, and a 20 times greater interface/volume ratio than in conventional Langmuir toughs.