Enhancing surgeons' gaze strategies in endoscopic surgery during simulated surgical emergency situations thanks to computer vision.

Deficient visualization in minimally invasive surgery often causes misperceptions, which can lead to an increase of iatrogenic lesions and complications. This is especially critical for novice surgeons, who are prone to adopt inadequate switching gaze strategies, thereby increasing the chance of unforeseen complications. In this paper the use of an additional computer-aided vision system was tested for improvement of the reaction of the surgeons to unforeseen complications. Gaze patterns were analyzed using a gaze tracker, as well as other metrics such as task completion time or reaction time to sudden bleeding. While completion time did not show significant difference between tested modalities (p<0.1), the reaction time showed a downward trend as more auxiliary computer-aided vision systems were added (p<0.005). These results support the benefits of including additional vision systems for minimally invasive surgery processes.Clinical Relevance- This work assesses the advantages of including an additional computer vision system to prevent unforeseen complications during minimally invasive surgeries.

An ML-Based Approach to Reconstruct Heart Rate from PPG in Presence of Motion Artifacts.

The heart rate (HR) is a widely used clinical variable that provides important information on a physical user's state. One of the most commonly used methods for ambulatory HR monitoring is photoplethysmography (PPG). The PPG signal retrieved from wearable devices positioned on the user's wrist can be corrupted when the user is performing tasks involving the motion of the arms, wrist, and fingers. In these cases, the obtained HR is altered as well. This problem increases when trying to monitor people with autism spectrum disorder (ASD), who are very reluctant to use foreign bodies, notably hindering the adequate attachment of the device to the user. This work presents a machine learning approach to reconstruct the user's HR signal using an own monitoring wristband especially developed for people with ASD. An experiment is carried out, with users performing different daily life activities in order to build a dataset with the measured signals from the monitoring wristband. From these data, an algorithm is applied to obtain a reliable HR value when these people are performing skill improvement activities where intensive wrist movement may corrupt the PPG.

Low-Cost Additive Manufacturing Techniques Applied to the Design of Planar Microwave Circuits by Fused Deposition Modeling.

This work presents a study on the implementation and manufacturing of low-cost microwave electronic circuits, made with additive manufacturing techniques using fused deposition modeling (FDM) technology. First, the manufacturing process of substrates with different filaments, using various options offered by additive techniques in the manufacture of 3D printing parts, is described. The implemented substrates are structurally analyzed by ultrasound techniques to verify the correct metallization and fabrication of the substrate, and the characterization of the electrical properties in the microwave frequency range of each filament is performed. Finally, standard and novel microwave filters in microstrip and stripline technology are implemented, making use of the possibilities offered by additive techniques in the manufacturing process. The designed devices were manufactured and measured with good results, which demonstrates the possibility of using low-cost 3D printers in the design process of planar microwave circuits.

Characterization of nanoparticles doped composites using ultrasound.

The aim of this work is the non-destructive automatic mechanical characterization of nanoparticles doped composites using ultrasound in order to understand and control the dispersion of the dopant nanoparticles in the final product. We present a method which is able to measure the elastic constants of composites (Youngs, Bulk, Shear Modulus and Poissons ratio), in addition to other parameters as density, sound velocity and thickness, providing information of the nanoparticles dispersion in the samples. All results are obtained with a single ultrasonic measure at each point of the samples' surface in an immersion setup with both pulse-echo and through-transmission measurements simultaneously, obtaining detailed information for all the samples' surface in a XY scanning. All the analysis is performed automatically, that is, no manual correction or adjustment is needed at any stage of the process. To validate the results, a polyester based resin has been analyzed with different concentrations of graphene nanoparticles as dopant. The method has shown to be very accurate and reliable. The resolution of the values obtained for the elastic constants is limited by the resolution in the velocities measurements, for which we have achieved a resolution in the order of cm/s, thus providing very accurate measurements of the elastic constants.

Influence of thermal treatment on the "in vitro" bioactivity of wollastonite materials.

The aim of this work was to study the influence of the composition and thermal treatment of the in vitro bioactivity of wollastonite materials obtained by sol-gel method. For this purpose, gels in the system SiO(2)-CaO were obtained applying calcium nitrate and tetraethoxysilicate as precursors. The gels were heated to 700 °C and then sintered up to 1400 °C. The bioactivity of the gel-derived materials in simulated body fluid (SBF) was investigated and characterized. Additional changes in ionic concentration, using inductively couple plasma atomic emission spectroscopy (ICP-AES), were determined. The results showed that all materials obtained were bioactive and indicate that the absence of phosphorous in the material composition is not an essential requirement for the development of a Hydroxyapatite layer. The bioactivity was influenced by the thermal treatment, the different phases (glass-phase, wollastonite and pseudowollastonite) as well as the porous size. On the gel-derived materials the bioactivity decreased with the sintering temperature.