Virtualware Group (Spain)

The development of a portable device created by 3D printing for fluorimetric measurements is an efficient tool for analytical applications in situ or in the laboratory presenting a wide field of applications in the environmental and food field. This device uses a light-emitting diode (LED) as radiation source and a digital microscope as a detector. Digital images obtained by the interaction between the radiation source and the sample were analyzed with the help of the YouCam software, the images were filed in JPEG format and processed with the Chemostat software.The entire system is connected to a notebook, which serves as a LED and detector power supply without the need for any additional power source. The proposed device was used for the determination in situ of quinine in water and beverages samples, respectively. For the validation of the developed system, the results obtained were compared with a conventional spectrofluorometer with a t-test at a 95% confidence level. The proposed system provides satisfactory precision and accuracy values. The proposed method presented detection and quantification limits of 0.99 and 1.46 mg L⁻¹, at a 95% confidence interval.

This work presents a simple, low cost, and portable spectrophotometer based on a digital microscope as a detector for the determination of the antioxidant activity and total phenolic content (TPC). The antioxidant activity was expressed as ascorbic acid equivalents (AAE) using the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) assay. The TPC value was measured using the Folin-Ciocalteu method. The color of the products was captured using a digital microscope powered through the USB output of a laptop. A digital microscope, held in a 3D printing device was used to take photos of the reaction product that was illuminated with the stable light source of the digital microscope. The pictures were analyzed for quantitation. For the DPPH assay, the developed method provided a working range from 0.6 to 6 mg L−1 of ascorbic acid with a limit of detection (LOD) of 0.2 mg L−1 and a relative standard deviation (RSD) of 2.2%. The TPC method provided a working range from 4.6 to 100 mg L−1 for gallic acid, with a LOD of 1.4 mg L−1 and a RSD of 1.3%. Results of the proposed system agree well with a conventional spectrophotometric method and have been successfully applied to measure the antioxidant activity and TPC of local Thai tea samples.

A new automated system based on a multi-pumping flow system (MPFS) for the spectrophotometric determination of total iron in various wine samples is presented. This analytical protocol is based on the complex formation between Fe (II) and 2-(5-bromo-2-pyridylazo)-5-(diethylamino)-phenol (Br-PADAP). The addition of ascorbic acid allows the determination of total iron by reducing the Fe (III) present in the samples to Fe (II). Several physical and chemical parameters, including the mixing coil length, the sample volume, the chromogenic reagent concentration, the pH, and the ascorbic acid concentration have been characterized in order to optimize the analytical conditions. The limits of detection and quantification were 34 µg L−1 and 114 µg L−1 respectively. The developed procedure requires minimal sample preparation.

A conductometric system with a multipumping module and a gas-diffusion cell has been developed to determine free and total sulfur dioxide (SO2) in wine. The developed method has two protocols to determine both types of SO2 using the same system. For free SO2, sulfite is converted to H2SO4 by acidification and diffusion with H2O2 in an acceptor channel. The sample was previously hydrolyzed by mixing the sample with NaOH and heated at 70 °C prior making the determination of total SO2 in order to break the bonds of the combined SO2. Free and total SO2 were determined in the ranges of 2.5–25.4 and 10.2–76.2 mg L−1 with a sample throughput of 13 and 12 h−1, respectively. The calibration curves of free and total SO2 were in the range of ΔG (mS cm−1) = (–1.0242 ± 0.2871) + (0.6613 ± 0.0201) [SO2, mg L−1], r2 of 0.997 and ΔG (mS cm−1) = (–0.5850 ± 0.1678) + (0.1236 ± 0.0033) [SO2, mg L−1], r2 of 0.997. The proposed automated method is simple and easy to apply for the determination of SO2 in wine using simple reagents.

Attention Deficit and Hyperactivity Disorder (ADHD) is associated with symptoms of inattention, hyperactivity, and impulsivity and affects a significant part of the population. Current treatment approaches entail high costs and are commonly based on stimulant medication, which may lead to undesirable side-effects. FocusLocus is an EU H2020 Innovation Action project that proposes a highly disruptive and innovative gamified monitoring and intervention programme for assisting children to manage and overcome ADHD symptoms. FocusLocus implements game mechanics that rely on cognitive training methods for mental and motor skill acquisition and behavioural change. The proposed programme is delivered through a multifaceted and adaptive gaming experience that permeates the child’s daily life and activities, spanning across virtual and physical space and comprising two modes: (a) a mobile tablet game for home use by individual users and (b) a multisensory mixed reality game for supervised sessions at specialised facilities (e.g., clinics). FocusLocus is designed to be highly personalised and adaptive to each child’s individual condition, symptoms, age, and character. By introducing advanced remote monitoring and management features, FocusLocus actively involves all stakeholders associated with children with ADHD (parents, clinicians, and special needs educators). FocusLocus employs an unobtrusive and multimodal sensing, assessment and monitoring methodology relying on (a) mobile device embedded sensors, (b) Electroencephalography (EEG) neurofeedback mechanisms, (c) Augmented Reality (AR) user tracking, (d) RFID-based object tracking for tangible user interaction, (e) in-game cognitive skill performance measurements, (f) cloud performance analytics, and (g) web-based secure access for remote profile monitoring and management.

Context. Extremely reddened AGB stars lose mass at high rates of >10^-5 Msun/yr. This is the very last stage of AGB evolution, in which stars in the mass range 2.0--4.0 Msun (for solar metallicity) should have been converted to C stars already. The extremely reddened AGB stars in the Galactic bulge are however predominantly O-rich, implying that they might be either low-mass stars or stars at the upper end of the AGB mass range. Aims. To determine the mass range of the most reddened AGB stars in the Galactic bulge. Methods. Using Virtual Observatory tools, we constructed spectral energy distributions of a sample of 37 evolved stars in the Galactic bulge with extremely red IRAS colours. We fitted DUSTY models to the observational data to infer the bolometric fluxes. Applying individual corrections for interstellar extinction and adopting a common distance, we determined luminosities and mass-loss rates, and inferred the progenitor mass range from comparisons with AGB evolutionary models. Results. The observed spectral energy distributions are consistent with a classification as reddened AGB stars, except for two stars, which are proto-planetary nebula candidates. For the AGB stars, we found luminosities in the range 3000--30,000 Lsun and mass-loss rates 10^-5--3x10^-4 Msun/yr. The corresponding mass range is 1.1--6.0 Msun assuming solar metallicity. Conclusions. Contrary to the predictions of the evolutionary models, the luminosity distribution is continuous, with many O-rich AGB stars in the mass range in which they should have been converted into C stars already. We suspect that bulge AGB stars have higher than solar metallicity and therefore may avoid the conversion to C-rich. The presence of low-mass stars in the sample shows that their termination of the AGB evolution also occurs during a final phase of very high mass-loss rate, leading to optically thick circumstellar shells.