University of Madeira

About: University of Madeira is a education organization based out in Funchal, Portugal. It is known for research contribution in the topics: Population & Dendrimer. The organization has 1014 authors who have published 2759 publications receiving 59457 citations.

Motor priming in virtual reality can augment motor-imagery training efficacy in restorative brain-computer interaction: a within-subject analysis

Abstract: The use of Brain–Computer Interface (BCI) technology in neurorehabilitation provides new strategies to overcome stroke-related motor limitations. Recent studies demonstrated the brain's capacity for functional and structural plasticity through BCI. However, it is not fully clear how we can take full advantage of the neurobiological mechanisms underlying recovery and how to maximize restoration through BCI. In this study we investigate the role of multimodal virtual reality (VR) simulations and motor priming (MP) in an upper limb motor-imagery BCI task in order to maximize the engagement of sensory-motor networks in a broad range of patients who can benefit from virtual rehabilitation training. In order to investigate how different BCI paradigms impact brain activation, we designed 3 experimental conditions in a within-subject design, including an immersive Multimodal Virtual Reality with Motor Priming (VRMP) condition where users had to perform motor-execution before BCI training, an immersive Multimodal VR condition, and a control condition with standard 2D feedback. Further, these were also compared to overt motor-execution. Finally, a set of questionnaires were used to gather subjective data on Workload, Kinesthetic Imagery and Presence. Our findings show increased capacity to modulate and enhance brain activity patterns in all extracted EEG rhythms matching more closely those present during motor-execution and also a strong relationship between electrophysiological data and subjective experience. Our data suggest that both VR and particularly MP can enhance the activation of brain patterns present during overt motor-execution. Further, we show changes in the interhemispheric EEG balance, which might play an important role in the promotion of neural activation and neuroplastic changes in stroke patients in a motor-imagery neurofeedback paradigm. In addition, electrophysiological correlates of psychophysiological responses provide us with valuable information about the motor and affective state of the user that has the potential to be used to predict MI-BCI training outcome based on user’s profile. Finally, we propose a BCI paradigm in VR, which gives the possibility of motor priming for patients with low level of motor control.

Towards a UML profile for interaction design: the wisdom approach

Abstract: The UML is recognized to be the dominant diagrammatic modeling language in the software industry. However, it's support for building interactive systems is still acknowledged to be insufficient. There is a common misconception that the same models developed to support the design of the application internals are also adequate to support interaction design, leveraging the usability aspects of the applications. In this paper we identify and discuss the major problems using the UML to document, specify and design interactive systems. Here we propose a UML profile for interactive systems development that leverages on human-computer interaction domain knowledge under the common notation and semantics of the UML. Our proposal integrates with existing object-oriented software engineering best practice, fostering coevolutionary development of interactive systems and enabling artifact change between software engineering and human-computer interaction.

An improved and fast UHPLC-PDA methodology for determination of L-ascorbic and dehydroascorbic acids in fruits and vegetables. Evaluation of degradation rate during storage

Abstract: This study provides a versatile validated method to determine the total vitamin C content, as the sum of the contents of L-ascorbic acid (L-AA) and dehydroascorbic acid (DHAA), in several fruits and vegetables and its degradability with storage time Seven horticultural crops from two different origins were analyzed using an ultra-high-performance liquid chromatographic–photodiode array (UHPLC-PDA) system, equipped with a new trifunctional high strength silica (100% silica particle) analytical column (100 mm × 21 mm, 17 μm particle size) using 01% (v/v) formic acid as mobile phase, in isocratic mode This new stationary phase, specially designed for polar compounds, overcomes the problems normally encountered in HPLC and is suitable for the analysis of large batches of samples without L-AA degradation In addition, it proves to be an excellent alternative to conventional C18 columns for the determination of L-AA in fruits and vegetables The method was fully validated in terms of linearity, detection (LOD) and quantification (LOQ) limits, accuracy, and inter/intra-day precision Validation experiments revealed very good recovery rate of 966 ± 44% for L-AA and 1031 ± 48 % for total vitamin C, good linearity with r 2 -values >0999 within the established concentration range, excellent repeatability (05%), and reproducibility (16%) values The LOD of the method was 22 ng/mL whereas the LOQ was 67 ng/mL It was possible to demonstrate that L-AA and DHAA concentrations in the different horticulture products varied oppositely with time of storage not always affecting the total amount of vitamin C during shelf-life Locally produced fruits have higher concentrations of vitamin C, compared with imported ones, but vegetables showed the opposite trend Moreover, this UHPLC-PDA methodology proves to be an improved, simple, and fast approach for determining the total content of vitamin C in various food commodities, with high sensitivity, selectivity, and resolving power within 3 min of run analysis