The Role of Interdigitated Electrodes in Printed and Flexible Electronics.

Flexible electronics, also referred to as printable electronics, represent an interesting technology for implementing electronic circuits via depositing electronic devices onto flexible substrates, boosting their possible applications. Among all flexible electronics, interdigitated electrodes (IDEs) are currently being used for different sensor applications since they offer significant benefits beyond their functionality as capacitors, like the generation of high output voltage, fewer fabrication steps, convenience of application of sensitive coatings, material imaging capability and a potential of spectroscopy measurements via electrical excitation frequency variation. This review examines the role of IDEs in printed and flexible electronics since they are progressively being incorporated into a myriad of applications, envisaging that the growth pattern will continue in the next generations of flexible circuits to come.

Camera-LiDAR Multi-Level Sensor Fusion for Target Detection at the Network Edge.

There have been significant advances regarding target detection in the autonomous vehicle context. To develop more robust systems that can overcome weather hazards as well as sensor problems, the sensor fusion approach is taking the lead in this context. Laser Imaging Detection and Ranging (LiDAR) and camera sensors are two of the most used sensors for this task since they can accurately provide important features such as target´s depth and shape. However, most of the current state-of-the-art target detection algorithms for autonomous cars do not take into consideration the hardware limitations of the vehicle such as the reduced computing power in comparison with Cloud servers as well as the reduced latency. In this work, we propose Edge Computing Tensor Processing Unit (TPU) devices as hardware support due to their computing capabilities for machine learning algorithms as well as their reduced power consumption. We developed an accurate and small target detection model for these devices. Our proposed Multi-Level Sensor Fusion model has been optimized for the network edge, specifically for the Google Coral TPU. As a result, high accuracy results are obtained while reducing the memory consumption as well as the latency of the system using the challenging KITTI dataset.

[Association between non-nutritive sweeteners and obesity risk among university students in Latin America]. / Asociación entre edulcorantes no nutritivos y riesgo de obesidad en estudiantes universitarios de Latinoamérica.

BACKGROUND: The association between non-nutritive sweeteners and obesity is controversial. AIM: To determine whether the consumption of non-nutritive sweeteners is related to higher risk for overweight or obesity among university students in Chile, Panama, Guatemala and Peru. MATERIAL AND METHODS: A total of 1,224 (472 from Chile, 300 from Panama, 248 from Guatemala and 204 from Peru) male and female university students aged between 18 and 26 years participated in the study. Each student reported their food intake (frequency of weekly consumption) in a survey that contained photos of foods containing non-nutritive sweeteners adapted for each country. Anthropometry was also measured. RESULTS: More than 80% of students consumed at least one product containing non-nutritive sweeteners. Females who ate acesulfame potassium and sucralose had a lower risk of overweight or obesity with an odds ratio (OR) of 0.5 (confidence intervals (CI) = 0.3-0.9; p = 0.003) and OR = 0.4 (IC = 0.2-0.8; p = 0.01), respectively. CONCLUSIONS: In this sample of Latinamerican university students, consumption of non-nutritive sweeteners was associated with lower risk of overweight only in females.

A Flexible Laser-Induced Graphene Memristor with Volatile Switching for Neuromorphic Applications.

Two-dimensional graphene and graphene-based materials are attracting increasing interest in neuromorphic computing applications by the implementation of memristive architectures that enable the closest solid-state equivalent to biological synapses and neurons. However, the state-of-the-art fabrication methodology involves routine use of high-temperature processes and multistepped chemical synthesis, often on a rigid substrate constraining the experimental exploration in the field to high-tech facilities. Here, we demonstrate the use of a one-step process using a commercial laser to fabricate laser-induced graphene (LIG) memristors directly on a flexible polyimide substrate. For the first time, a volatile resistive switching phenomenon is reported in the LIG without using any additional materials. The absence of any precursor or patterning mask greatly simplifies the process while reducing the cost and providing greater controllability. The fabricated memristors show multilevel resistance-switching characteristics with high endurance and tunable timing characteristics. The recovery time and the trigger pulse-dependent state change are shown to be highly suitable for its use as a synaptic element and in the realization of leaky-integrate and fire neuron in neuromorphic circuits.

Editorial: Functional Nanomaterials for Sensor Applications.

Functional nanomaterials have become one of the most fascinating fields in nanotechnology [...].

Reconfigurable Electronic Platforms: A Top-Down Approach to Learn about Design and Integration of Electronic Systems.

This case report presents a real example of a study which introduces the use of reconfigurable platforms in the teaching of electronics engineering to establish a bridge between theory and practice. This gap is one of the major concerns of the electronics engineering students. Different strategies, such as simulation tools or breadboard implementations, have been followed so far to make it easier for students to practice what they study in lectures. However, many students still claim to have problems when they face real practical implementations. The use of reconfigurable platforms as a teaching tool is proposed to provide the students the possibility of fast experimentation, reducing both development time and the learning curve. In addition, reconfigurable platforms available on the market make this methodology suitable to be applied throughout the different courses of their curricula. The feasibility of this approach is demonstrated in a course at the M.Eng. level, where the objective is the study, design and development of electronic sensor nodes. We firmly consider, based on the students' results and reflections collected during the course, that this methodology helps students to address the theoretical framework from a practical viewpoint, as well as to acquire some of the fundamental skills for their professional careers, such as the usage of communication protocols and embedded systems programming, in a more intuitive way when compared to traditional teaching methodologies.

Fabrication and Characterization of Humidity Sensors Based on Graphene Oxide-PEDOT:PSS Composites on a Flexible Substrate.

In this paper, we present a simple, fast, and cost-effective method for the large-scale fabrication of high-sensitivity humidity sensors on flexible substrates. These sensors consist of a micro screen-printed capacitive structure upon which a sensitive layer is deposited. We studied two different structures and three different sensing materials by modifying the concentration of poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate (PEDOT:PSS) in a graphene oxide (GO) solution. The results show that the aggregation of the PEDOT:PSS to the GO can modify its electrical properties, boosting the performance of the capacitive sensors in terms of both resistive losses and sensitivity to relative humidity (RH) changes. Thus, in an area less than 30 mm2, the GO/PEDOT:PSS-based sensors can achieve a sensitivity much higher (1.22 nF/%RH at 1 kHz) than other similar sensors presented in the literature which, together with their good thermal stability, time response, and performance over bending, demonstrates that the manufacturing approach described in this work paves the way for the mass production of flexible humidity sensors in an inexpensive way.

Carbon Dots as Sensing Layer for Printed Humidity and Temperature Sensors.

This work presents an innovative application of carbon dots (Cdots) nanoparticles as sensing layer for relative humidity detection. The developed sensor is based on interdigitated capacitive electrodes screen printed on a flexible transparent polyethylene terephthalate (PET) film. Cdots are deposited on top of these electrodes. An exhaustive characterization of the nanoparticles has been conducted along with the fabrication of the sensor structure. The accompanied experiments give all the sensibility to the Cdots, showing its dependence with temperature and exciting frequency. To the best of our knowledge, this work paves the path to the use of these kind of nanoparticles in printed flexible capacitive sensors aimed to be employed in the continuously expanding Internet of Things ecosystem.

Printed and Flexible Microheaters Based on Carbon Nanotubes.

This work demonstrates a cost-effective manufacturing method of flexible and fully printed microheaters, using carbon nanotubes (CNTs) as the heating element. Two different structures with different number of CNT layers have been characterized in detail. The benchmarking has been carried out in terms of maximum operating temperature, as well as nominal resistance and input power for different applied voltages. Their performances have been compared with previous reports for similar devices, fabricated with other technologies. The results have shown that the heaters presented can achieve high temperatures in a small area at lower voltages and lower input power. In particular, the fully printed heaters fabricated on a flexible substrate covering an area of 3.2 mm2 and operating at 9.5 V exhibit a maximum temperature point above 70 °C with a power consumption below 200 mW. Therefore, we have demonstrated that this technology paves the way for a cost-effective large-scale fabrication of flexible microheaters aimed to be integrated in flexible sensors.

Comparison of Laser-Synthetized Nanographene-Based Electrodes for Flexible Supercapacitors.

In this paper, we present a comparative study of a cost-effective method for the mass fabrication of electrodes to be used in thin-film flexible supercapacitors. This technique is based on the laser-synthesis of graphene-based nanomaterials, specifically, laser-induced graphene and reduced graphene oxide. The synthesis of these materials was performed using two different lasers: a CO2 laser with an infrared wavelength of λ = 10.6 µm and a UV laser (λ = 405 nm). After the optimization of the parameters of both lasers for this purpose, the performance of these materials as bare electrodes for flexible supercapacitors was studied in a comparative way. The experiments showed that the electrodes synthetized with the low-cost UV laser compete well in terms of specific capacitance with those obtained with the CO2 laser, while the best performance is provided by the rGO electrodes fabricated with the CO2 laser. It has also been demonstrated that the degree of reduction achieved with the UV laser for the rGO patterns was not enough to provide a good interaction electrode-electrolyte. Finally, we proved that the specific capacitance achieved with the presented supercapacitors can be improved by modifying the in-planar structure, without compromising their performance, which, together with their compatibility with doping-techniques and surface treatments processes, shows the potential of this technology for the fabrication of future high-performance and inexpensive flexible supercapacitors.

Laser-Fabricated Reduced Graphene Oxide Memristors.

Finding an inexpensive and scalable method for the mass production of memristors will be one of the key aspects for their implementation in end-user computing applications. Herein, we report pioneering research on the fabrication of laser-lithographed graphene oxide memristors. The devices have been surface-fabricated through a graphene oxide coating on a polyethylene terephthalate substrate followed by a localized laser-assisted photo-thermal partial reduction. When the laser fluence is appropriately tuned during the fabrication process, the devices present a characteristic pinched closed-loop in the current-voltage relation revealing the unique fingerprint of the memristive hysteresis. Combined structural and electrical experiments have been conducted to characterize the raw material and the devices that aim to establish a path for optimization. Electrical measurements have demonstrated a clear distinction between the resistive states, as well as stable memory performance, indicating the potential of laser-fabricated graphene oxide memristors in resistive switching applications.

Inexpensive Graphene Oxide Heaters Lithographed by Laser.

In this paper, we present a simple and inexpensive method for the fabrication of high-performance graphene-based heaters on different large-scale substrates through the laser photothermal reduction of graphene oxide (laser-reduced graphene-oxide, LrGO). This method allows an efficient and localized high level of reduction and therefore a good electrical conductivity of the treated films. The performance of the heaters is studied in terms of steady-state temperature, power consumption, and time response for different substrates and sizes. The results show that the LrGO heaters can achieve stable steady-state temperatures higher than 200 °C when a voltage of 15 V is applied, featuring a time constant of around 4 s and a heat transfer coefficient of ~200 °C cm2/W. These characteristics are compared with other technologies in this field, demonstrating that the fabrication approach described in this work is competitive and promising to fabricate large-scale flexible heaters with a very fast response and high steady-state temperatures in a cost-effective way. This technology can be easily combined with other fabrication methods, such as screen printing or spray-deposition, for the manufacturing of complete sensing systems where the temperature control is required to adjust functionalities or to tune sensitivity or selectivity.

In-Depth Study of Laser Diode Ablation of Kapton Polyimide for Flexible Conductive Substrates.

This work presents a detailed study of the photothermal ablation of Kapton® polyimide by a laser diode targeting its electrical conductivity enhancement. Laser-treated samples were structurally characterized using Scanning Electron Microscopy (SEM), Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS), as well as Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy. The results show that the laser-assisted ablation constitutes a simple one-step and environmental friendly method to induce graphene-derived structures on the surface of polyimide films. The laser-modified surface was also electrically characterized through the Transmission Line Method (TLM) aiming at the improvement of the conductivity of the samples by tuning the laser power and the extraction of the contact resistance of the electrodes. Once the laser-ablation process is optimized, the samples increase their conductivity up to six orders of magnitude, being comparable to that of graphene obtained by chemical vapor deposition or by the reduction of graphene-oxide. Additionally, we show that the contact resistance can be decreased down to promising values of ∼2 Ω when using silver-based electrodes.

Implementación de la terapia miofuncional orofacial en una clínica de posgrado de Ortodoncia / Implementation of orofacial myofunctional therapy in a graduate education dental clinic

Introducción: la terapia miofuncional orofacial es el conjunto de técnicas que intervienen en los desórdenes miofuncionales que afectan el comportamiento de la dinámica del sistema estomatognático, su equilibrio y su funcionamiento integrando sus acciones durante un tratamiento de ortopedia maxilar y ortodoncia. Objetivo: desarrollar la implementación del servicio de terapia miofuncional en una Clínica de Ortodoncia y Ortopedia Maxilar como una estrategia de intervención ante la presencia de desórdenes miofuncionales. Métodos: se consideraron dos momentos metodológicos. En el primer momento, se estableció el diagnóstico situacional asistencial con una investigación descriptiva transversal a una muestra de 68 informes fonoaudiológicos de pacientes. Igualmente, para el establecimiento del diagnóstico académico y profesional se realizó una encuesta a 35 personas, 83 por ciento estudiantes de posgrado y 17 por ciento docentes. En el segundo momento, se realizó una revisión documental como soporte teórico de las guías de manejo. Resultados: las fases de diagnóstico situacional confirman la pertinencia de implementar un servicio de terapia miofuncional dado que el 100 por ciento de los pacientes presentaron un diagnóstico de desorden miofuncional, deglución atípica completa en el 60 por ciento y la deglución atípica anterior en el 29 por ciento. En lo referente al diagnóstico profesional, el 91 por ciento de los encuestados presentó una experiencia positiva con la terapia miofuncional tanto en la fase evaluativa como terapéutica. Se consolidaron las guías de manejo que rigen el servicio tanto en acciones evaluativas, diagnósticas y terapéuticas. Conclusiones: se justifica la pertinencia de la implementación de la terapia miofuncional no solo desde los efectos bucofaciales, sino desde la prevención de estos. El desarrollo de programas de intervención clínico educativo en el marco legal de promoción y prevención deben ser contundentes en las clínicas de Ortodoncia y Ortopedia Maxilar, donde se ejecuten actividades de protección específica, detección temprana y atención oportuna en la salud bucal(AU)

Introduction: orofacial myofunctional therapy is the set of techniques used to treat myofunctional disorders affecting the dynamics of the stomatognathic system, its balance and operation, integrating their actions during maxillary orthopedics and orthodontics treatment. Objective: implement the myofunctional therapy service in a maxillary orthopedic / orthodontic clinic as an intervention strategy for myofunctional disorders. Methods: Methodologically, the study was structured into two stages. In the first stage situational care diagnostics was established via a cross-sectional descriptive study of a sample of 68 phonoaudiological reports about patients. Academic and professional diagnostics was based on a survey applied to 35 people, 83 percent of whom were post-graduate students and 17 percent were teachers. The second stage consisted in a document review to provide theoretical foundation to the management guides. Results: the situational diagnostics stages confirm the relevance of implementing a myofunctional therapy service, since 100 percent of the patients were diagnosed with myofunctional disorder, with total atypical deglutition in 60 percent and anterior atypical deglutition in 29 percent. Professional diagnostics showed that 91 percent of respondents had had a positive experience with myofunctional therapy in either its evaluative or therapeutic stage. Consolidation was conducted of the management guides governing the service in terms of evaluative, diagnostic and therapeutic actions. Conclusions: pertinence of the implementation of myofunctional therapy is justified, not only by orofacial effects, but also by their prevention. Development of clinical educational intervention programs within the legal framework for promotion and prevention should be forcefully conducted in maxillary orthopedic / orthodontic clinics, where actions will be performed aimed at specific protection, early detection and timely care in dental practice(AU)

[Comparison between the quality of life and nutritional status of nutrition students and those of other university careers at the Santo Thomas University in Chile]. / Comparación en calidad de vida y estado nutricional entre alumnos de nutrición y dietética y de otras carreras universitarias de la Universidad Santo Tomás de Chile.

OBJECTIVE: To determine and compare the quality of life, nutritional status, and self-perceived body image between nutrition students and students from other careers from the University Santo Tomás-Viña del Mar. METHODS: We evaluated 200 student volunteers (100 nutrition students and 100 students from other careers) with a quality of life survey, a nutritional evaluation, and a survey of body image perception. RESULTS: The group of nutritional students perceived a lower quality of life, consumed less tobacco, and was less sedentary. Women of the nutritional group had a lower BMI and showed a lower hip circumference. Men of the nutritional group also showed a lower hip circumference. The nutritional group consumed more milk, chicken, and fish in their diet. Both groups presented an elevated consumption of alcohol. The concordance between BMI and body image was low, 34% in the nutritional group and 38% in the other careers group (Kappa 0.04 and 0.02). CONCLUSION: With respect to perception of quality of life, students from other careers perceived a better quality of life, however students from the nutritional group presented better nutritional status and selection of food.

Comparison of nonnutritive artificial sweetener consumption among university students in latin american: multicentric study

The Objective this study is to compare the consumption of artificial sweeteners by sex and BMI status among university students in Peru, Chile, Guatemala and Panama. Survey of consumption of artificial sweeteners containing foods was designed and applied, adapted for each country with pictures of surveyed foods. After the survey application, a total of 1,229 participants male and female both university students from 4 different Latin American countries: Chile (n=473); Panama (n=300); Guatemala (n=253); Peru (n=204) were submitted to a anthropometry measeurement. Over 80% of students ate at least 1 food that contained artificial sweeteners, acesulphame-k, sucralose, and aspartame had the highest levels of consumption. Females in Chile and Guatemala ate the most sucralose (25.7 (6.6-50.9), p<0.05; 38.3 (15.1-82.5). Males in Panama ate the most acesulphame-k, (35.3 (11.5-91.5), p<0,05). Females had a positive correlation between artificial sweetener consumption and BMI for: acesulphame-k, aspartame and cyclamate. Males had a negative relationship between acesulphame-k, aspartame and BMI (p<0.05). We found a high consumption of artificial sweeteners among both male and female Latin Americ an university students, with differences by country, sex and BMI status(AU)

El objetivo del estudio es comparar el consumo de edulcorantes artificiales no nutritivos por sexo y estado nutricional (IMC) entre los estudiantes universitarios en Perú, Chile, Guatemala y Panamá. Se diseñó y aplicó una encuesta de consumo de alimentos que contienen edulcorantes artificiales no nutritivos, adaptado para cada país con fotos de alimentos encuestas. Posteriormente se aplicó la encuesta y una evaluación antropometrica entre 1.229 estudiantes universitarios en 4 diferentes países de América Latina: Chile (n = 473); Panamá (n = 300); Guatemala (n = 253); Perú (n = 204). Más del 80% de los estudiantes comía al menos 1 alimento que contiene edulcorantes artificiales, acesulfamo-K, sucralosa, aspartame y tenían los niveles más altos de consumo. Las mujeres en Chile y Guatemala comsumieron más sucralosa (25,7 (6,6-50,9), p <0,05; 38,3 (15,1-82,5). Los hombres de Panama comsumían más acesulfamo-K, (35,3 (11,5-91,5), p <0,05) Las mujeres tenían una correlación positiva entre el consume de edulcorante artificial y el IMC para: acesulfamo-K, aspartamo y ciclamato hombres tenían una relación negativa entre el acesulfamo K, aspartamo y el IMC (p <0,05). Encontramos un alto consumo de edulcorantes artificiales entre los estudiantes de ambos sexos en las universidades de América Latina, con diferencias por país, sexo e IMC(AU)

Asociación entre edulcorantes no nutritivos y riesgo de obesidad en estudiantes universitarios de Latinoamérica / Association between non-nutritive sweeteners and obesity risk among university students in Latin America

Background: The association between non-nutritive sweeteners and obesity is controversial. Aim: To determine whether the consumption of non-nutritive sweeteners is related to higher risk for overweight or obesity among university students in Chile, Panama, Guatemala and Peru. Material and Methods: A total of 1,224 (472 from Chile, 300 from Panama, 248 from Guatemala and 204 from Peru) male and female university students aged between 18 and 26 years participated in the study. Each student reported their food intake (frequency of weekly consumption) in a survey that contained photos of foods containing non-nutritive sweeteners adapted for each country. Anthropometry was also measured. Results: More than 80% of students consumed at least one product containing non-nutritive sweeteners. Females who ate acesulfame potassium and sucralose had a lower risk of overweight or obesity with an odds ratio (OR) of 0.5 (confidence intervals (CI) = 0.3-0.9; p = 0.003) and OR = 0.4 (IC = 0.2-0.8; p = 0.01), respectively. Conclusions: In this sample of Latinamerican university students, consumption of non-nutritive sweeteners was associated with lower risk of overweight only in females.