Artículos, conferencias, monografías

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Esta colección está formada por artículos, conferencias, comunicaciones y otras publicaciones elaborados por miembros de la Universitat Politècnica de València.

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3D patient-specific spinal cord computational model for SCS management: potential clinical applications
(IOP Publishing, 2021-06) Solanes, Carmen; Dura, Jose L.; Canós, M.A.; De Andres, Jose; Marti-Bonmati, Luis; Saiz Rodríguez, Francisco Javier; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería Industrial; Centro de Investigación e Innovación en Bioingeniería; Surgicen, S.L.
[EN] Objective. Although spinal cord stimulation (SCS) is an established therapy for treating neuropathic chronic pain, in tonic stimulation, postural changes, electrode migration or badly-positioned electrodes can produce annoying stimulation (intercostal neuralgia) in about 35% of the patients. SCS models are used to study the effect of electrical stimulation to better manage the stimulation parameters and electrode position. The goal of this work was to develop a realistic 3D patient-specific spinal cord model from a real patient and develop a future clinical application that would help physicians to optimize paresthesia coverage in SCS therapy. Approach. We developed two 3D patient-specific models from a high-resolution MRI of two patients undergoing SCS treatment. The model consisted of a finite element model of the spinal cord and a sensory myelinated nerve fiber model. The same simulations were performed with a generalized spinal cord model and we compared the results with the clinical data to evaluate the advantages of a patient-specific model. To identify the geometrical parameters that most influence the stimulation predictions, a sensitivity analysis was conducted. We used the patient-specific model to perform a clinical application involving the pre-implantation selection of electrode polarity and study the effect of electrode offset. Main results. The patient-specific model correlated better with clinical data than the generalized model. Electrode-dura mater distance, dorsal cerebrospinal fluid (CSF) thickness, and CSF diameter are the geometrical parameters that caused significant changes in the stimulation predictions. Electrode polarity could be planned and optimized to stimulate the patient's painful dermatomes. The addition of offset in parallel electrodes would not have been beneficial for one of the patients of this study because they reduce neural activation displacement. Significance. This is the first study to relate the activation area model prediction in dorsal columns with the clinical effect on paresthesia coverage. The outcomes show that 3D patient-specific models would help physicians to choose the best stimulation parameters to optimize neural activation and SCS therapy in tonic stimulation.
A comparative analysis of printing techniques by using an active concentric ring electrode for bioelectrical recording
(Emerald, 2015) García Breijo, Eduardo; Prats Boluda, Gema; Lidón Roger, José Vicente; Ye Lin, Yiyao; Garcia Casado, Francisco Javier; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Técnica Superior de Ingeniería Industrial; Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico; Centro de Investigación e Innovación en Bioingeniería; Ministerio de Economía y Competitividad
Purpose This paper aims to present a comparison between three types of manufacturing techniques, namely, screen-printed, inkjet and gravure, using different types of inks, for the implementation of concentric ring electrodes which permit estimation of Laplacian potential on the body surface. Design/methodology/approach Flexible concentric ring electrodes not only present lower skin electrode contact impedance and lower baseline wander than rigid electrodes but are also less sensitive to interference and motion artefacts. The above three techniques allow printing of conductive inks on flexible substrates, and with this work, the authors aim to study which is the best technique and ink to obtain the best electrode response. Findings From the results obtained regarding ink thickness, resistivity, electrode resistance and other performance parameters derived from electrocardiographic signal recording tests, it can be said that concentric electrodes using the screen-printing and inkjet techniques are suitable for non-invasive bioelectric signal acquisition. Originality/value The development of new types of inks and substrates for the electronics industry and the adaptation of new manufacturing techniques allow for an improvement in the development of electrodes and sensors.
A Comparative Study of Vaginal Labor and Caesarean Section Postpartum Uterine Myoelectrical Activity
(MDPI AG, 2020-06) Díaz-Martínez, María del Alba; Mas-Cabo, Javier; Prats Boluda, Gema; Garcia Casado, Francisco Javier; Cardona-Urrego, Karen; Monfort-Ortiz, Rogelio; Lopez-Corral, Angel; De Arriba-Garcia, Maria; Perales, Alfredo; Ye Lin, Yiyao; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Técnica Superior de Ingeniería Industrial; Centro de Investigación e Innovación en Bioingeniería; Generalitat Valenciana; Agencia Estatal de Investigación; European Regional Development Fund; Ministerio de Economía y Competitividad
[EN] Postpartum hemorrhage (PPH) is one of the major causes of maternal mortality and morbidity worldwide, with uterine atony being the most common origin. Currently there are no obstetrical techniques available for monitoring postpartum uterine dynamics, as tocodynamometry is not able to detect weak uterine contractions. In this study, we explored the feasibility of monitoring postpartum uterine activity by non-invasive electrohysterography (EHG), which has been proven to outperform tocodynamometry in detecting uterine contractions during pregnancy. A comparison was made of the temporal, spectral, and non-linear parameters of postpartum EHG characteristics of vaginal deliveries and elective cesareans. In the vaginal delivery group, EHG obtained a significantly higher amplitude and lower kurtosis of the Hilbert envelope, and spectral content was shifted toward higher frequencies than in the cesarean group. In the non-linear parameters, higher values were found for the fractal dimension and lower values for Lempel-Ziv, sample entropy and spectral entropy in vaginal deliveries suggesting that the postpartum EHG signal is extremely non-linear but more regular and predictable than in a cesarean. The results obtained indicate that postpartum EHG recording could be a helpful tool for earlier detection of uterine atony and contribute to better management of prophylactic uterotonic treatment for PPH prevention.
A computational model predicts adjunctive pharmacotherapy for cardiac safety via selective inhibition of the late cardiac Na current
(Elsevier, 2016) Yang, Pei-Chi; El-Bizri, Nesrine; Romero Pérez, Lucia; Giles, Wayne; Rajamani, Sridharan; Belardinelli, Luiz; Clancy, Colleen E; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería Industrial; Centro de Investigación e Innovación en Bioingeniería
[EN] Background: The QT interval is a phase of the cardiac cycle that corresponds to action potential duration (APD) including cellular repolarization (T-wave). In both clinical and experimental settings, prolongation of the QT interval of the electrocardiogram (ECG) and related proarrhythmia have been so strongly associated that a prolonged QT interval is largely accepted as surrogate marker for proarrhythmia. Accordingly, drugs that prolong the QT interval are not considered for further preclinical development resulting in removal of many promising drugs from development. While reduction of drug interactions with hERG is an important goal, there are promising means to mitigate hERG block. Here, we examine one possibility and test the hypothesis that selective inhibition of the cardiac late Na current (I-NaL) by the novel compound GS-458967 can suppress proarrhythmic markers. Methods and results: New experimental data has been used to calibrate INaL in the Soltis-Saucerman computationally based model of the rabbit ventricular action potential to study effects of GS-458967 on INaL during the rabbit ventricular AP. We have also carried out systematic in silico tests to determine if targeted block of INaL would suppress proarrhythmia markers in ventricular myocytes described by TRIaD: Triangulation, Reverse use dependence, beat-to-beat Instability of action potential duration, and temporal and spatial action potential duration Dispersion. Conclusions: Our computer modeling approach based on experimental data, yields results that suggest that selective inhibition of INaL modifies all TRIaD related parameters arising from acquired Long-QT Syndrome, and thereby reduced arrhythmia risk. This study reveals the potential for adjunctive pharmacotherapy via targeted block of INaL to mitigate proarrhythmia risk for drugs with significant but unintended off-target hERG blocking effects.
A considerable improvement of the traditional FPGA-based digital design methodology by using an Arduino sensor board
(Editorial Universitat Politècnica de València, 2020-04-10) Martínez Peiró, Marcos Antonio; Larrea Torres, Miguel Ángel; Lidón Roger, José Vicente; Jiménez Jiménez, Yolanda; Torres Curado, Rubén; Tébar Ruiz, Ángel; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico; Instituto de Instrumentación para Imagen Molecular; Centro de Investigación e Innovación en Bioingeniería
[EN] The traditional way to learn and teach Digital Systems has been changing over the last decades by the use of Hardware Description Languages (HDL) and Field Programmable Gate Array (FPGA) evaluation boards. The use of an Arduino development kit with different sensors connected to the FPGA upsizes the students experience in the area of Digital Systems. A temperature and humidity ambience sensor combined with an ultrasound sensor to measure distance can effectively be used by students to implement its first serial data converter that takes the sensor data and shows the obtained values from the Arduino in the seven segment display of the FPGA kit. After three years of experience in the new grade courses at the UPV Telecommunication School the number of students enjoying this new way to learn the subject Fundamentals of Digital Electronics (FSD) has dramatically risen up with an increase of a 20% in the number of students that pass the subject and that select the electronic branch of telecommunication studies in the future semesters.
A continuum and computational framework for viscoelastodynamics: I. Finite deformation linear models
(Elsevier, 2021-11-01) Liu, Ju; Latorre Ferrús, Marcos; Marsden, Alison L.; Dpto. de Mecánica de los Medios Continuos y Teoría de Estructuras; Escuela Técnica Superior de Ingeniería Industrial; Centro de Investigación e Innovación en Bioingeniería; National Institutes of Health, EEUU; Southern University of Science and Technology; Guangdong-Hong Kong-Macao Joint Laboratory for Data-Driven Fluid Mechanics and Engineering Applications
[EN] This work concerns the continuum basis and numerical formulation for deformable materials with viscous dissipative mechanisms. We derive a viscohyperelastic modeling framework based on fundamental thermomechanical principles. Since most large deformation problems exhibit isochoric properties, our modeling work is constructed based on the Gibbs free energy in order to develop a continuum theory using pressure-primitive variables, which is known to be well-behaved in the incompressible limit. A set of general evolution equations for the internal state variables is derived. With that, we focus on a family of free energies that leads to the so-called finite deformation linear model. Our derivation elucidates the origin of the evolution equations of that model, which was originally proposed heuristically and thus lacked formal compatibility with the underlying thermodynamics. In our derivation, the thermodynamic inconsistency is clarified and rectified. A classical model based on the identical polymer chain assumption is revisited and is found to have non-vanishing viscous stresses in the equilibrium limit, which is counter-intuitive in the physical sense. Because of that, we then discuss the relaxation property of the non-equilibrium stress in the thermodynamic equilibrium limit and its implication on the form of free energy. A modified version of the identical polymer chain model is then proposed, with a special case being the model proposed by G. Holzapfel and J. Simo. Based on the consistent modeling framework, a provably energy stable numerical scheme is constructed for incompressible viscohyperelasticity using inf¿sup stable elements. In particular, we adopt a suite of smooth generalization of the Taylor¿Hood element based on Non-Uniform Rational B-Splines (NURBS) for spatial discretization. The temporal discretization is performed via the generalized-alpha scheme. We present a suite of numerical results to corroborate the proposed numerical properties, including the nonlinear stability, robustness under large deformation, and the stress accuracy resolved by the higher-order elements. Additionally, the pathological behavior of the original identical polymer chain model is numerically identified with an unbounded energy decaying. This again underlines the importance of demanding vanishing non-equilibrium stress in the equilibrium limit.
A continuum model for tension-compression asymmetry in skeletal muscle
(Elsevier, 2018-01) Latorre Ferrús, Marcos; Mohammadkhah, Melika; Simms, Ciaran K.; Montáns, Francisco Javier; Dpto. de Mecánica de los Medios Continuos y Teoría de Estructuras; Escuela Técnica Superior de Ingeniería Industrial; Centro de Investigación e Innovación en Bioingeniería; Ministerio de Economía y Competitividad; Ministerio de Educación, Cultura y Deporte
[EN] Experiments on passive skeletal muscle on different species show a strong asymmetry in the observed tension-compression mechanical behavior. This asymmetry shows that the tension modulus is two orders of magnitude higher than the compression modulus. Until now, traditional analytical constitutive models have been unable to capture that strong asymmetry in anisotropic solids using the same material parameters. In this work we present a model which is able to accurately capture five experimental tests in chicken pectoralis muscle, including the observed tension-compression asymmetry. However, aspects of the anisotropy of the tissue are not captured by the model.
A fast method for monitoring the shifts in resonance frequency and dissipation of the QCM sensors of a Monolithic array in biosensing applications
(Institute of Electrical and Electronics Engineers, 2021-03-01) Fernández Díaz, Román; Calero-Alcarria, María Del Señor; García Narbón, José Vicente; Reiviakine, Ilya; Arnau Vives, Antonio; Jiménez Jiménez, Yolanda; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Escuela Técnica Superior de Ingeniería del Diseño; Centro de Investigación e Innovación en Bioingeniería; European Commission; European Regional Development Fund; Agencia Estatal de Investigación; Ministerio de Economía y Competitividad
[EN] Improvement of data acquisition rate remains as an important challenge in applications with Quartz Crystal Microbalance (QCM) technology where high throughput is required. To address this challenge, we developed a fast method capable of measuring the response of a large number of sensors and/or overtones, with a high time resolution. Our method, which can be implemented in a low-cost readout electronic circuit, is based on the estimation of fr (frequency shift) and D (dissipation shift) from measurements of the sensor response obtained at a single driving frequency. By replacing slow fitting procedures with a direct calculation, the time resolution is only limited by the physical characteristics of the sensor (resonance frequency and quality factor), but not by the method itself. Capabilities of the method are demonstrated by monitoring multiple overtones with a single 5 MHz sensor and a Monolithic QCM array comprising 24 50MHz-sensors. Accuracy of the method is validated and compared with the state-of-the-art, as well as with a reference method based on impedance analysis.
A Flexible Multiring Concentric Electrode for Non-Invasive Identification of Intestinal Slow Waves
(MDPI AG, 2018) Zena-Giménez, Victor Fabián; Garcia Casado, Francisco Javier; Ye Lin, Yiyao; García Breijo, Eduardo; Prats Boluda, Gema; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Técnica Superior de Ingeniería Industrial; Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico; Centro de Investigación e Innovación en Bioingeniería; Ministerio de Economía, Industria y Competitividad
[EN] Developing new types of optimized electrodes for specific biomedical applications can substantially improve the quality of the sensed signals. Concentric ring electrodes have been shown to provide enhanced spatial resolution to that of conventional disc electrodes. A sensor with different electrode sizes and configurations (monopolar, bipolar, etc.) that provides simultaneous records would be very helpful for studying the best signal-sensing arrangement. A 5-pole electrode with an inner disc and four concentric rings of different sizes was developed and tested on surface intestinal myoelectrical recordings from healthy humans. For good adaptation to a curved body surface, the electrode was screen-printed onto a flexible polyester substrate. To facilitate clinical use, it is self-adhesive, incorporates a single connector and can perform dry or wet (with gel) recordings. The results show it to be a versatile electrode that can evaluate the optimal configuration for the identification of the intestinal slow wave and reject undesired interference. A bipolar concentric record with an outer ring diameter of 30 mm, a foam-free adhesive material, and electrolytic gel gave the best results.
A High Fundamental Frequency (HFF)-based QCM Immunosensor for Tuberculosis Detection
(Bentham Science Publishers, 2017) Montoya Baides, Ángel; March Iborra, Mª Del Carmen; Montagut Ferizzola, Yeison Javier; Moreno Tamarit, Mª José; Manclus Ciscar, Juan José; Arnau Vives, Antonio; Jiménez Jiménez, Yolanda; Jaramillo, Marisol; Marin, Paula A.; Torres-Villa, Róbinson Alberto; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Centro de Investigación e Innovación en Bioingeniería; AWSensors S.L.; Departamento Administrativo de Ciencia, Tecnología e Innovación, Colombia
Tuberculosis, one of the oldest diseases affecting human beings, is still considered as a world public health problem by the World Health Organization. Therefore, there is a need for new and more powerful analytical methods for early illness diagnosis. With this idea in mind, the development of a High Fundamental Frequency (HFF) piezoelectric immunosensor for the sensitive detection of tuberculosis was undertaken. A 38 kDa protein secreted by Mycobacterium tuberculosis was first selected as the target biomarker. Then, specific monoclonal antibodies (MAbs) were obtained. Myc-31 MAb, which showed the highest affinity to the analyte, was employed to set up a reference enzyme-linked immunosorbent assay (ELISA) with a limit of detection of 14 ng mL-1 of 38 kDa antigen. For the development of the HFF piezoelectric immunosensor, 100 MHz quartz crystals were used as transducer elements. The gold electrode surface was functionalized by covalent immobilization of the target biomarker through mixed self-assembled monolayers (mSAM) of carboxylic alkane thiols. A competitive immunoassay based on Myc-31 MAb was integrated with the transducer as sensing bio-recognition event. Reliable assay signals were obtained using low concentrations of antigen for functionalization and MAb for the competitive immunoassay. Under optimized conditions, the HFF immunosensor calibration curve for 38 kDa determination showed a limit of detection as low as 11 ng mL-1 of the biomarker. The high detectability attained by this immunosensor, in the picomolar range, makes it a promising tool for the easy, direct and sensitive detection of the tuberculosis biomarker in biological fluids such as sputum.
A mechanobiologically equilibrated constrained mixture model for growth and remodeling of soft tissues
(John Wiley & Sons, 2018-12) Latorre Ferrús, Marcos; Humphrey, Jay D.; Dpto. de Mecánica de los Medios Continuos y Teoría de Estructuras; Escuela Técnica Superior de Ingeniería Industrial; Centro de Investigación e Innovación en Bioingeniería; National Institutes of Health, EEUU; Ministerio de Economía y Competitividad; Ministerio de Educación, Cultura y Deporte
[EN] Growth and remodeling of soft tissues is a dynamic process and several theoretical frameworks have been developed to analyze the time-dependent, mechanobiological and/or biomechanical responses of these tissues to changes in external loads. Importantly, general processes can often be conveniently separated into truly non-steady contributions and steady-state ones. Depending on characteristic times over which the external loads are applied, time-dependent models can sometimes be specialized to respective time-independent formulations that simplify the mathematical treatment without compromising the goodness of the particularized solutions. Very few studies have analyzed the long-term, steady-state responses of soft tissue growth and remodeling following a direct approach. Here, we derive a mechanobiologically equilibrated formulation that arises from a general constrained mixture model. We see that integral-type evolution equations that characterize these general models can be written in terms of an equivalent set of time-independent, nonlinear algebraic equations that can be solved efficiently to yield long-term outcomes of growth and remodeling processes in response to sustained external stimuli. We discuss the mathematical conditions, in terms of orders of magnitude, that yield the particularized equations and illustrate results numerically for general arterial mechano-adaptations.
A Multichannel Microfluidic Sensing Cartridge for Bioanalytical Applications of Monolithic Quartz Crystal Microbalance
(MDPI AG, 2020-11-24) Calero-Alcarria, María Del Señor; Fernández Díaz, Román; GARCIA MOLLA, PABLO; García Narbón, José Vicente; García, María; Gamero-Sandemetrio, Esther; Reviakine, Ilya; Arnau Vives, Antonio; Jiménez Jiménez, Yolanda; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Escuela Técnica Superior de Ingeniería del Diseño; Centro de Investigación e Innovación en Bioingeniería; Agencia Estatal de Investigación; European Regional Development Fund; Ministerio de Economía y Competitividad
[EN] Integrating acoustic wave sensors into lab-on-a-chip (LoC) devices is a well-known challenge. We address this challenge by designing a microfluidic device housing a monolithic array of 24 high-fundamental frequency quartz crystal microbalance with dissipation (HFF-QCMD) sensors. The device features six 6-µL channels of four sensors each for low-volume parallel measurements, a sealing mechanism that provides appropriate pressure control while assuring liquid confinement and maintaining good stability, and provides a mechanical, electrical, and thermal interface with the characterization electronics. We validate the device by measuring the response of the HFF-QCMD sensors to the air-to-liquid transition, for which the robust Kanazawa¿Gordon¿Mason theory exists, and then by studying the adsorption of model bioanalytes (neutravidin and biotinylated albumin). With these experiments, we show how the effects of the protein¿surface interactions propagate within adsorbed protein multilayers, offering essentially new insight into the design of affinity-based bioanalytical sensors
A multiscale computational model of arterial growth and remodeling including Notch signaling
(Springer-Verlag, 2023-10) van Asten, Jordy G. M.; Latorre Ferrús, Marcos; Karakaya, Cansu; Baaijens, Frank P. T.; Sahlgren, Cecilia M.; Ristori, Tommaso; Humphrey, Jay; Loerakker, Sandra; Dpto. de Mecánica de los Medios Continuos y Teoría de Estructuras; Escuela Técnica Superior de Ingeniería Industrial; Centro de Investigación e Innovación en Bioingeniería; European Commission
[EN] Blood vessels grow and remodel in response to mechanical stimuli. Many computational models capture this process phenomenologically, by assuming stress homeostasis, but this approach cannot unravel the underlying cellular mechanisms. Mechano-sensitive Notch signaling is well-known to be key in vascular development and homeostasis. Here, we present a multiscale framework coupling a constrained mixture model, capturing the mechanics and turnover of arterial constituents, to a cell-cell signaling model, describing Notch signaling dynamics among vascular smooth muscle cells (SMCs) as influenced by mechanical stimuli. Tissue turnover was regulated by both Notch activity, informed by in vitro data, and a phenomenological contribution, accounting for mechanisms other than Notch. This novel framework predicted changes in wall thickness and arterial composition in response to hypertension similar to previous in vivo data. The simulations suggested that Notch contributes to arterial growth in hypertension mainly by promoting SMC proliferation, while other mechanisms are needed to fully capture remodeling. The results also indicated that interventions to Notch, such as external Jagged ligands, can alter both the geometry and composition of hypertensive vessels, especially in the short term. Overall, our model enables a deeper analysis of the role of Notch and Notch interventions in arterial growth and remodeling and could be adopted to investigate therapeutic strategies and optimize vascular regeneration protocols.
A new class of plastic flow evolution equations for anisotropic multiplicative elastoplasticity based on the notion of a corrector elastic strain rate
(Elsevier, 2018-03) Latorre Ferrús, Marcos; Montáns, Francisco Javier; Dpto. de Mecánica de los Medios Continuos y Teoría de Estructuras; Escuela Técnica Superior de Ingeniería Industrial; Centro de Investigación e Innovación en Bioingeniería; Ministerio de Economía y Competitividad; Ministerio de Educación, Cultura y Deporte
[EN] We herein present a new continuum theory for both isotropic and anisotropic elastoplasticity at large strains. The new framework has the following properties: (1) It is valid for non-moderate large strains, (2) it is valid for both elastic and plastic anisotropy, (3) its description in rate form is parallel to that of the infinitesimal formulation, (4) it is compatible with the multiplicative decomposition, (5) results in a similar framework in any stress-strain work-conjugate pair, (6) it is consistent with the principle of maximum plastic dissipation and (7) does not impose any restriction on the plastic spin, which must be given as an independent constitutive equation. Furthermore, when formulated using logarithmic strain measures in the intermediate configuration: (8) it may be easily integrated using a classical backward-Euler rule resulting in an additive update. All these properties are obtained simply by considering a plastic evolution in terms of a corrector rate of the proper elastic strain. This new continuum theory is a natural framework for elastoplasticity of both metals and soft materials and solves the (so-coined by Simo) rate issue.
A New Protocol Test For Physical Activity Research In Obese Children (Etiobe Project)
(Brenda K. Wiederhold, Giuseppe Riva, 2009) Guixeres Provinciale, Jaime; Zaragozá Álvarez, Irene; Alcañiz Raya, Mariano Luis; Gomis-Tena Dolz, Julio; Dpto. de Ingeniería Electrónica; Dpto. de Ingeniería Gráfica; Instituto Universitario de Investigación en Tecnología Centrada en el Ser Humano; Escuela Técnica Superior de Ingeniería Industrial; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Centro de Investigación e Innovación en Bioingeniería
[EN] A new protocol is presented to validate TIPS (portable physiological monitoring device designed by I3BH that can get respiration, ecg and activity of the patient) for physical habits detection. Physiological and activity parameters and data from questionnaires have been acquired from a group of obese & nonobese children (n=20). Children completed activities from sedentary level to vigorous level. Preliminary results show variability on the response of children¿s effort and feasibility of TIPS platform as an ambulatory tool.
A novel bismuth-based lead-free piezoelectric transducer immunosensor for carbaryl quantification
(Elsevier, 2019-04-15) Fernández-Benavides, D.A.; Cervera Chiner, Lourdes; Jiménez Jiménez, Yolanda; Arias de Fuentes, O.; Montoya, Ángel; Muñoz-Saldaña, J.; Dpto. de Tecnología de Alimentos; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Centro de Investigación e Innovación en Bioingeniería; Consejo Nacional de Ciencia y Tecnología, México; Ministerio de Economía y Competitividad
[EN] A novel BNT-BKT-BT piezoelectric ceramic immunosensor, tested for quantification of the pesticide carbaryl is here presented. The measuring format was based on a competitive immunoassay of immobilized conjugate using monoclonal antibodies (MAbs) as specific immunoreagent. The immunosensor is able to detect concentrations of the analyte from one and up to three orders of magnitude below the reported values of high- and low- frequency quartz crystal commercial resonators (HFF-QCM and QCM), respectively. Furthermore, the minimum content of quantified carbaryl is 0.11 ¿g L-1, which is clearly lower than reported values of any commercial quartz-based biosensors. Such measurement characteristics are only possible due to the high electromechanical coupling factor (kt) of the Bi-based piezoelectric ceramic, approaching the commercial QCM, HFF-QCM and ELISA techniques and strongly enhancing the sensitivity of the immunoassay.
A Real-Time Method for Improving Stability of Monolithic Quartz Crystal Microbalance Operating under Harsh Environmental Conditions
(MDPI AG, 2021-06) Fernández Díaz, Román; Calero-Alcarria, María Del Señor; Jiménez Jiménez, Yolanda; Arnau Vives, Antonio; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Escuela Técnica Superior de Ingeniería del Diseño; Centro de Investigación e Innovación en Bioingeniería; European Commission; Agencia Estatal de Investigación
[EN] Monolithic quartz crystal microbalance (MQCM) has recently emerged as a very promising technology suitable for biosensing applications. These devices consist of an array of miniaturized QCM sensors integrated within the same quartz substrate capable of detecting multiple target analytes simultaneously. Their relevant benefits include high throughput, low cost per sensor unit, low sample/reagent consumption and fast sensing response. Despite the great potential of MQCM, unwanted environmental factors (e.g., temperature, humidity, vibrations, or pressure) and perturbations intrinsic to the sensor setup (e.g., mechanical stress exerted by the measurement cell or electronic noise of the characterization system) can affect sensor stability, masking the signal of interest and degrading the limit of detection (LoD). Here, we present a method based on the discrete wavelet transform (DWT) to improve the stability of the resonance frequency and dissipation signals in real time. The method takes advantage of the similarity among the noise patterns of the resonators integrated in an MQCM device to mitigate disturbing factors that impact on sensor response. Performance of the method is validated by studying the adsorption of proteins (neutravidin and biotinylated albumin) under external controlled factors (temperature and pressure/flow rate) that simulate unwanted disturbances.
A Surface Electromyogram Evaluation of the Postural Freedom Effects in Laparoscopic Surgery
(IEEE, 2019-07-27) Pace-Bedetti, Horacio M.; Martínez de Juan, José Luís; Conejero Rodilla, Andrés; Prats Boluda, Gema; Dpto. de Ingeniería Electrónica; Dpto. de Dibujo; Escuela Técnica Superior de Ingeniería del Diseño; Instituto de Diseño para la Fabricación y Producción Automatizada; Escuela Técnica Superior de Ingeniería Industrial; Centro de Investigación e Innovación en Bioingeniería
[EN] It has been demonstrated that laparoscopic procedures benefit patients in terms of recovery time, exposure to infections and trauma. Nevertheless, it increases the number of problems for the surgeons, including the frequency and duration of awkward postures for surgeons. The repetition of these movements is considered the main cause for musculoskeletal disorders in surgeons' upper limbs. The goal of this study is to evaluate the muscular activity and muscular fatigue effect produced by both, a conventional instrument and an instrument provided with the Postural Freedom (PF) feature; which consists in a ball socket articulation that allows a variable handle-to-shaft angle, on a conventional laparoscopic pistol-grip handle. Seventeen participants were evaluated during a static simulation using both instruments. Surface electromyography was used to compare the instruments in terms of muscular activity in each target position and muscular fatigue produced in the muscles trapezius, deltoids, biceps, and flexor carpi radialis. Trapezius and deltoids were the muscles most affected. Entrance and exit targets and targets facing the participants showed the higher muscular activity values. The PF prototype reduced muscular activity in all the muscles and in the majority of the target positions showing a reduction greater than 70% of the activity required by the trapezius and deltoid muscles in comparison to the conventional tool. Muscular fatigue was produced by both instruments but it presented lower frequency values with PF prototype. The results indicated that the use of conventional instruments impacts negatively on muscular activity during laparoscopic procedures, in terms of positions adopted. The PF feature in laparoscopic instrumentation reduced the muscular activity and also decreased the signals of muscular fatigue in the muscles evaluated in comparison with the conventional tool.
A three-dimensional human atrial model with fiber orientation. Electrograms and arrhythmic activation patterns relationship
(Public Library of Science, 2013-02) Tobón Zuluaga, Catalina; Ruiz Villa, Carlos Alberto; Heidenreich, Elvio; Romero Pérez, Lucia; Hornero, Fernando; Saiz Rodríguez, Francisco Javier; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería Industrial; Centro de Investigación e Innovación en Bioingeniería; Ministerio de Ciencia e Innovación; Ministerio de Industria, Turismo y Comercio; Generalitat Valenciana; Universitat Politècnica de València
The most common sustained cardiac arrhythmias in humans are atrial tachyarrhythmias, mainly atrial fibrillation. Areas of complex fractionated atrial electrograms and high dominant frequency have been proposed as critical regions for maintaining atrial fibrillation; however, there is a paucity of data on the relationship between the characteristics of electrograms and the propagation pattern underlying them. In this study, a realistic 3D computer model of the human atria has been developed to investigate this relationship. The model includes a realistic geometry with fiber orientation, anisotropic conductivity and electrophysiological heterogeneity. We simulated different tachyarrhythmic episodes applying both transient and continuous ectopic activity. Electrograms and their dominant frequency and organization index values were calculated over the entire atrial surface. Our simulations show electrograms with simple potentials, with little or no cycle length variations, narrow frequency peaks and high organization index values during stable and regular activity as the observed in atrial flutter, atrial tachycardia (except in areas of conduction block) and in areas closer to ectopic activity during focal atrial fibrillation. By contrast, cycle length variations and polymorphic electrograms with single, double and fragmented potentials were observed in areas of irregular and unstable activity during atrial fibrillation episodes. Our results also show: 1) electrograms with potentials without negative deflection related to spiral or curved wavefronts that pass over the recording point and move away, 2) potentials with a much greater proportion of positive deflection than negative in areas of wave collisions, 3) double potentials related with wave fragmentations or blocking lines and 4) fragmented electrograms associated with pivot points. Our model is the first human atrial model with realistic fiber orientation used to investigate the relationship between different atrial arrhythmic propagation patterns and the electrograms observed at more than 43000 points on the atrial surface.
A Three-Dimensional Model of the Human Atria With Heterogeneous Wall Thickness and Fibre Transmurallity - A Realistic Platform for the Study of Atrial Fibrillation
(IEEE, 2019-09-11) Rocher-Ventura, Sara; Martínez, Laura; López, Alejandro; Ferrer Albero, Ana; Sánchez-Quintana, Damián; Saiz Rodríguez, Francisco Javier; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería de Telecomunicación; Escuela Técnica Superior de Ingeniería Industrial; Centro de Investigación e Innovación en Bioingeniería; GENERALITAT VALENCIANA
[EN] Multiscale cardiac modelling has been increasingly used since it provides a promising framework to improve our understanding of atrial fibrillation physiopathology. In this study, we present a highly detailed threedimensional model of the human atria including heterogenous wall thickness and fibre transmurality, suggested as relevant factor in arrhythmogenic dynamics. We hypothesized that the structural definition of computer models influences the electrical propagation and to test it we compared the fibrillatory activity of the new model with two models less detailed anatomically but with the same electrical and tissular properties. The three studied models generated different arrhythmic patterns, with the appearance of re-entrant drivers at different atrial regions. We conclude that it is very important to use complete realistic atrial models, especially for atrial fibrillation studies, to obtain reliable results. Additionally, the developed model allows to consider new variables of study involving atrial wall thickness transmurality.

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