Assessment of Muscle Coordination Changes Caused by the Use of an Occupational Passive Lumbar Exoskeleton in Laboratory Conditions

[EN] The introduction of exoskeletons in industry has focused on improving worker safety. Exoskeletons have the objective of decreasing the risk of injury or fatigue when performing physically demanding tasks. Exoskeletons' effect on the muscles is one of the most common focuses of their assessment. The present study aimed to analyze the muscle interactions generated during load-handling tasks in laboratory conditions with and without a passive lumbar exoskeleton. The electromyographic data of the muscles involved in the task were recorded from twelve participants performing load-handling tasks. The correlation coefficient, coherence coefficient, mutual information, and multivariate sample entropy were calculated to determine if there were significant differences in muscle interactions between the two test conditions. The results showed that muscle coordination was affected by the use of the exoskeleton. In some cases, the exoskeleton prevented changes in muscle coordination throughout the execution of the task, suggesting a more stable strategy. Additionally, according to the directed Granger causality, a trend of increasing bottom-up activation was found throughout the task when the participant was not using the exoskeleton. Among the different variables analyzed for coordination, the most sensitive to changes was the multivariate sample entropy.This study was funded by Fundación Prevent.Iranzo-Egea, S.; Belda-Lois, J.; Martínez-De-Juan, JL.; Prats-Boluda, G. (2023). Assessment of Muscle Coordination Changes Caused by the Use of an Occupational Passive Lumbar Exoskeleton in Laboratory Conditions. Sensors. 23(24):1-14. https://doi.org/10.3390/s23249631114232

The effect of postural freedom to increase the neutral positions during laparoscopic surgery

[EN] Laparoscopic technique has demonstrated numerous advantages compared to open conventional surgery. Nevertheless, this procedure increases the surgeons fatigue and thus, the potential to commit errors that may harm the patient during the operation. The post-surgery pain is also augmented because the surgeons are forced to adopt non-neutral postures during the practice. This study reveals how a postural freedom element could help surgeons to improve the postural hygiene. During this study, thirteen participants with and without previous experience in laparoscopic surgery performed a test with two instruments: a prototype that implement this postural freedom concept and a conventional fixed instrument. The results obtained indicate that the postural freedom element allows the participants to maintain neutral positions during greatest part of the experiment and suggest that the implementation of an articulated element could increases the neutral positions adopted during a real laparoscopic procedure. The use of the postural freedom concept allowed to the participants to reduce the awkward positions during upper limb motions and to reduce displacements, avoiding extreme abductions that are common with the conventional fixed instruments.Pace-Bedetti, HM.; Dolz, JF.; Martínez-De-Juan, JL.; Conejero Rodilla, A. (2019). The effect of postural freedom to increase the neutral positions during laparoscopic surgery. International Journal on Interactive Design and Manufacturing (IJIDeM). 13(2):627-631. https://doi.org/10.1007/s12008-018-00527-6S62763113

Controlled deformation of vesicles by flexible structured media

Liquid crystalline (LC) materials, such as actin or tubulin networks, are known to be capable of deforming the shape of cells. Here, elements of that behavior are reproduced in a synthetic system, namely, a giant vesicle suspended in a LC, which we view as a first step toward the preparation of active, anisotropic hybrid systems that mimic some of the functionality encountered in biological systems. To that end, we rely on a coupled particle-continuum representation of deformable networks in a nematic LC represented at the level of a Landau–de Gennes free energy functional. Our results indicate that, depending on its elastic properties, the LC is indeed able to deform the vesicle until it reaches an equilibrium, anisotropic shape. The magnitude of the deformation is determined by a balance of elastic and surface forces. For perpendicular anchoring at the vesicle, a Saturn ring defect forms along the equatorial plane, and the vesicle adopts a pancake-like, oblate shape. For degenerate planar anchoring at the vesicle, two boojum defects are formed at the poles of the vesicle, which adopts an elongated, spheroidal shape. During the deformation, the volume of the topological defects in the LC shrinks considerably as the curvature of the vesicle increases. These predictions are confirmed by our experimental observations of spindle-like shapes in experiments with giant unilamellar vesicles with planar anchoring. We find that the tension of the vesicle suppresses vesicle deformation, whereas anchoring strength and large elastic constants promote shape anisotropy

A Surface Electromyogram Evaluation of the Postural Freedom Effects in Laparoscopic Surgery

[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.Pace-Bedetti, HM.; Martínez-De-Juan, JL.; Conejero Rodilla, A.; Prats-Boluda, G. (2019). A Surface Electromyogram Evaluation of the Postural Freedom Effects in Laparoscopic Surgery. IEEE. 3143-3146. https://doi.org/10.1109/EMBC.2019.88579193143314

Optimized Feature Subset Selection Using Genetic Algorithm for Preterm Labor Prediction Based on Electrohysterography

[EN] Electrohysterography (EHG) has emerged as an alternative technique to predict preterm labor, which still remains a challenge for the scientific-technical community. Based on EHG parameters, complex classification algorithms involving non-linear transformation of the input features, which clinicians found difficult to interpret, were generally used to predict preterm labor. We proposed to use genetic algorithm to identify the optimum feature subset to predict preterm labor using simple classification algorithms. A total of 203 parameters from 326 multichannel EHG recordings and obstetric data were used as input features. We designed and validated 3 base classifiers based on k-nearest neighbors, linear discriminant analysis and logistic regression, achieving F1-score of 84.63 ± 2.76%, 89.34 ± 3.5% and 86.87 ± 4.53%, respectively, for incoming new data. The results reveal that temporal, spectral and non-linear EHG parameters computed in different bandwidths from multichannel recordings provide complementary information on preterm labor prediction. We also developed an ensemble classifier that not only outperformed base classifiers but also reduced their variability, achieving an F1-score of 92.04 ± 2.97%, which is comparable with those obtained using complex classifiers. Our results suggest the feasibility of developing a preterm labor prediction system with high generalization capacity using simple easy-to-interpret classification algorithms to assist in transferring the EHG technique to clinical practice.This work was supported by the Spanish Ministry of Economy and Competitiveness, the European Regional Development Fund (MCIU/AEI/FEDER, UE RTI2018-094449-A-I00-AR) and by the Generalitat Valenciana (AICO/2019/220).Nieto-Del-Amor, F.; Prats-Boluda, G.; Martínez-De-Juan, JL.; Díaz-Martínez, MDA.; Monfort-Ortiz, R.; Diago-Almela, VJ.; Ye Lin, Y. (2021). Optimized Feature Subset Selection Using Genetic Algorithm for Preterm Labor Prediction Based on Electrohysterography. Sensors. 21(10):1-15. https://doi.org/10.3390/s21103350S115211

Estudio integral de la metodología aprendizaje basado en problemas para la adquisición de competencias transversales con técnica de trabajo en equipo y evaluación individualizada

[ES] El trabajo en grupo es una de las metodologías docentes más comunes para la adquisición de competencias específicas y transversales. La metodología de aprendizaje basado en problemas (ABP) se implantó para el desarrollo grupal de competencias en los estudiantes del Grado en Ingeniería Biomédica. No obstante, se detectó una excesiva carga de trabajo no presencial para los alumnos (71±35 h). Asimismo, la evaluación del trabajo grupal no reflejaba fielmente el aprendizaje individual de cada estudiante. En este trabajo se realiza un estudio integral de la implantación de la metodología ABP con especial énfasis en la evaluación del aprendizaje individual en las actividades grupales. El análisis de la dedicación no presencial del alumnado (26±15 h por 1.8 ECTS) y del profesorado (~14.3 h/ECTS) muestra que la metodología propuesta es altamente sostenible y aunque supuso una reducción significativa en el tiempo de dedicación, no afectó a la percepción del alumnado sobre la adquisición de competencias. Además, los alumnos consideran que la metodología ABP permite mejorar significativamente el nivel de dominio del manejo de Matlab. En cuanto al sistema de evaluación que valora el aprendizaje individual del manejo de Matlab se ha encontrado cierta resistencia al cambio del método de evaluación por parte del alumnado.Este trabajo está subvencionado parcialmente por la ETSII UPV y el Vicerrectorado de Estudios, Calidad y Acreditación de la UPV (PIME B03, Convocatoria 2017-2018).Ye Lin, Y.; Prats-Boluda, G.; Bosch Roig, I.; Martínez-De-Juan, JL. (2019). Estudio integral de la metodología aprendizaje basado en problemas para la adquisición de competencias transversales con técnica de trabajo en equipo y evaluación individualizada. REDINE. 512-517. http://hdl.handle.net/10251/181094S51251

Spanish Expressive Voices: corpus for emotion research in Spanish

A new emotional multimedia database has been recorded and aligned. The database comprises speech and video recordings of one actor and one actress simulating a neutral state and the Big Six emotions: happiness, sadness, anger, surprise, fear and disgust. Due to a careful design and its size (more than 100 minutes per emotion), the recorded database allows comprehensive studies on emotional speech synthesis, prosodic modelling, speech conversion, far-field speech recognition and speech and video-based emotion identification. The database has been automatically labelled for prosodic purposes (5% was manually revised). The whole database has been validated thorough objective and perceptual tests, achieving a validation score as high as 89%

Preliminary results on the application of the aminoacid racemization technique in the Murcia Region (SE Iberian Peninsula) and their interest in paleoseismological research

Geochronology is a critical issue in paleoseismological research. The aminoacid racemization technique shows important advantages respect to more traditional dating methods; not just for the lower costs and promptness, also because the object to analyze is relatively frequent, in this study: terrestrial gastropods. Furthermore, the costs of the analysis are by far faster and cheaper compared to other dating techniques. Racemization results allow comparing the relative age from different sedimentary units from one trench to another.Additionally, the racemization technique can also be used as a geochronological tool, provided a calibration curve has been first obtained for the particular climate for the area and, ideally, for a particular genus. In this study we show the results obtained from the analysis of 40 samples of terrestrial gastropods from 7 different trenches located in the Murcia Region (SE Spain). Making use of the D/L ratio of aspartic acid we show the coherence found between relative stratigraphic ages and the racemization age. Finally, we show a provisional conversion equation between age of racemization, obtained from Torres et al. (1997) algorithm, and the likely age of the samEl control geocronológico es una cuestión crítica en los estudios de paleosismología. La técnica de racemización de aminoácidos ofrece importantes ventajas respecto a otros métodos de datación, tanto en los costes y rapidez, como en la facilidad de encontrar el objeto de análisis; en este estudio, gasterópodos terrestres. Los resultados permiten comparar la edad relativa entre unidades sedimentarias diferentes de unas zanjas a otras. La técnica de racemización también es una herramienta geocronológica, si bien es necesario primero establecer una curva de calibración para el ambiente climático de la zona e, idealmente, para un género concreto. En este estudio se muestran los resultados obtenidos en 40 muestras de gasterópodos terrestres recogidas en 7 zanjas de investigación paleosismológica en la Región de Murcia. Haciendo uso de la relación D/L del ácido aspártico mostramos la coherencia entre las edades relativas estratigráficas y su edad de racemización. Finalmente, proponemos una relación provisional de conversión entre las edades de racemización obtenidas por el algoritmo de Torres et al. (1997) para gasterópodos de la zona central de la Península Ibérica y la edad probable de las muestra

Reflexiones en torno a la evaluación de las actividades del proceso de enseñanza-aprendizaje

La evaluación es un proceso sistemático, continuo e integral destinado a determinar hasta qué punto han sido alcanzados los objetivos educativos. En ella se aúnan dos actividades fundamentales: medir y emitir juicios de valor a partir, de los datos. Sin embargo, a pesar de la claridad de estos conceptos la forma de evaluar a los alumnos todavía sigue plagada de importantes contradicciones entre los profesores, lo que manifiesta unas conductas didácticas alejadas de lo que debiera ser una pedagogía basada en la evidencia. El objetivo de este proyecto es evidenciar las citadas discrepancias, entre los agentes del proceso de enseñanza aprendizaje (alumnos y profesores), a la hora de elaborar, realizar y calificar las pruebas de evaluación (“exámenes”) de los alumnos de varias disciplinas relacionadas con la Biomedicina. La metodología empleada ha consistido en aplicar a los estudiantes un sencillo cuestionario con preguntas de elección múltiple. A partir de los resultados, se pretende reflexionar sobre conjunto de criterios sólidos que permitan realizar las evaluaciones de los alumnos con mayor validez, fiabilidad, objetividad y pertinencia, como recomienda la OMS en su Guía Pedagógica para el Personal de Salud

A randomized trial of the discontinuation of primary and secondary prophylaxis against Pneumocystis carinii pneumonia after highly active antiretroviral therapy in patients with HIV infection

Background: Prophylaxis against Pneumocystis carinii pneumonia is indicated in patients with human immunodeficiency virus (HIV) infection who have less than 200 CD4 cells per cubic millimeter and in those with a history of P. carinii pneumonia. However, it is not clear whether prophylaxis can be safely discontinued after CD4 cell counts increase in response to highly active antiretroviral therapy. Methods: We conducted a randomized trial of the discontinuation of primary or secondary prophylaxis against P. carinii pneumonia in HIV-infected patients with a sustained response to antiretroviral therapy, defined by a CD4 cell count of 200 or more per cubic millimeter and a plasma HIV type 1 (HIV-1) RNA level of less than 5000 copies per milliliter for at least three months. Prophylactic treatment was restarted if the CD4 cell count declined to less than 200 per cubic millimeter. Results: The 474 patients receiving primary prophylaxis had a median CD4 cell count at entry of 342 per cubic millimeter, and 38 percent had detectable HIV-1 RNA. After a median follow-up period of 20 months (388 person-years), there had been no episodes of P. carinii pneumonia in the 240 patients who discontinued prophylaxis (95 percent confidence interval, 0 to 0.85 episode per 100 person-years). For the 113 patients receiving secondary prophylaxis, the median CD4 cell count at entry was 355 per cubic millimeter, and 24 percent had detectable HIV-1 RNA. After a median follow-up period of 12 months (65 person-years), there had been no episodes of P. carinii pneumonia in the 60 patients who discontinued prophylaxis (95 percent confidence interval, 0 to 4.57 episodes per 100 person-years). Conclusions: In HIV-infected patients receiving highly active antiretroviral therapy, primary and secondary prophylaxis against P. carinii pneumonia can be safely discontinued after the CD4 cell count has increased to 200 or more per cubic millimeter for more than three months