This paper presents a solution for energy microgeneration through energy harvesting by taking advantage of temperature differences that are converted into electrical energy using the Seebeck effect. A thermoelectric microconverter for energy scavenging systems that can supply low-power electronics was fabricated using thin films of bismuth and antimony tellurides. Thin films of n-type bismuth (Bi 2 Te 3) and p-type antimony (Sb 2 Te 3) tellurides were obtained by thermal coevaporation with thermoelectric figures of merit (ZT) at room temperature of 0.84 and 0.5 and power factors (P F × 10 −3 [W • K −1 • m −2 ]) of 4.87 and 2.81, respectively. The films were patterned by photolithography and wet-etching techniques. The goal for this thermoelectric microconverter is to supply individual electroencephalogram (EEG) modules composed by an electrode, processing electronics, and an antenna, where the power consumption ranges from hundredths of microwatts to a few milliwatts. Moreover, these wireless EEG modules allow patients to maintain their mobility while simultaneously having their electrical brain activity monitored.

BackgroundOutcomes of catheter ablation of atrial fibrillation (AF) are variable and the predictors of success require further elucidation since the identification of correctable risk factors could help to optimize therapy. We aimed to assess the impact of body mass index (BMI) in the overall safety and efficacy of catheter ablation of AF, with emphasis on the use of cryoballoon ablation and novel oral anticoagulants.Methods and ResultsThere were 2497 consecutive patients undergoing catheter ablation of AF in 7 European high volume centers were stratified according to BMI (normal weight <25 kg/m2, pre‐obese 25–30 kg/m2, obesity 30–35 kg/m2, and morbid obesity ≥35 kg/m2) and comparisons of procedural outcomes evaluated. Pre‐obese and obese patients presented more comorbidities (hypertension, diabetes mellitus, and sleep apnea), and had higher rates of non‐paroxysmal AF ablation procedures. The rate of atrial 12‐month arrhythmia relapse increased alongside with BMI (35.2%, 35.7%, 43.6%, and 48.0% P<0.001). During a median follow‐up of 18.8 months (interquartile range 11–28), after adjusting for all baseline differences, BMI was an independent predictor of relapse (hazard ratio=1.01 per kg/m2; 95% CI 1.01–1.02; P=0.002), adding incremental predictive value to obstructive sleep apnea. BMI was not a predictor for any of the reported complications. Using novel oral anticoagulants and cryoballoon ablation was safe and efficacy was comparable with vitamin‐K antagonists and radiofrequency ablation.ConclusionsObese patients present with a more adverse comorbidity profile, more advanced forms of AF, and have lower chances of being free from AF relapse after ablation. Use of novel oral anticoagulants and cryoballoon ablation may be an option in this patient group.

This paper presents a new type of dry electrodes for acquisition of biopotentials and stimulation. These dry electrodes are composed by 16 microtip structures (by forming an array of 4 × 4 microtips), which were fabricated through bulk micromachining of a 1 0 0 -type silicon substrate in a potassium hydroxide (KOH) solution. The fabrication process was trimmed in a way that each microtip presents solid angles of 54.7 • , a width in the range 150-200 m, a height of 100-200 m, and an inter-microtip spacing of 2 mm. The electrodes have a thin layer (obtained by reactive DC-sputtering) of iridium oxide (IrO) to improve the contact with the skin. These dry electrodes penetrate the outer skin layer (i.e. stratum corneum that is 10 m thick) to allow a direct contact with the electrolyte fluids of the inner skin layers. The new electrode avoid the use of conductive gels and reduce the skin preparation time in EEG experiments, which may take about 45 min for a set of 32 standard silver/silver chloride (Ag/AgCl) electrodes. The electrode-electrolyte impedance spectrometry (IS) of the IrO thin-films was performed in a saline solution, 0.9% concentration by weight, to mimic the electrode-tissue interface. The IS measured results for the IrO coatings were comparable to the results observed for the standard Ag/AgCl electrodes. The new dry microtips array constitutes an inexpensive, low resistance and mechanically robust alternative electrode for non-invasive biopotential recording/stimulation with fast application on skin.

A respiratory and cardiac-frequency sensor has been designed and manufactured to monitor both components with a single fiber Bragg grating (FBG) sensor. The main innovation of the explored system is the structure in which the FBG sensor is embedded. A specially developed polymeric foil allowed the simultaneous detection of heart rate and respiration cycles. The PVC has been designed to enhance the sensor sensitivity. In order to retrieve both components individually, a signal processing system was implemented for filtering out the respiratory and cardiac frequencies. The developed solution was tested along with a commercial device for referencing, from which the proposed system reliability is concluded. This optical-fiber system type has found an application niche in magnetic resonance imaging (MRI) exam rooms, where no other types of sensors than optical ones are advised to enter due to the electromagnetic interference.

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