Transiciones microestructurales inducidas por cizalla en sistemas acuosos de un tensioactivo catiónico tipo esterquat

Se presenta un estudio basado en técnicas reológicas y de microscopía electrónica de barrido de bajas temperaturas (cryo-SEM) sobre los cambios de microestructura provocados por el flujo en cizalla de dispersiones acuosas de un tensioactivo catiónico tipo esterquat. Se comparan micrografías de cryo-SEM y las respuestas bajo cizalla oscilatoria de dispersiones sin y con cloruro de calcio. Esta última no presenta zona de comportamiento viscoelástico lineal, apuntando su respuesta no lineal a un fenomeno de estructuracion inducida por cizalla. Ensayos transitorios de inicioal flujo, entre 0,1s -1 y 2000s-1, confirman que se producen aumentos de viscosidad más acusados con el tiempo de flujo a medida que aumenta la velocidad de cizalla. La téecnica de cryo-SEM apoya que los resultados transitorios se deben a que un exceso de energía mecánica provoca transiciones de bicapas de tensioactivo a vesículas. Diferentes ensayos reológicos realizados en serie avalan la naturaleza irreversible, en la escala de tiempo de esta investigación, de las transiciones microestructurales inducidas por cizalla. Se demuestra que a pesar de la presencia de cloruro de calcio (0,1%), la aplicación de una velocidad de cizalla excesiva puede dar lugar a la aparición de respuestas viscoelasticas lineales significativas

Presencia de Vulpes praeglacialis (Kormos, 1932) en el yacimiento pleistoceno de la Sierra de Quibas (Abanilla, Murcia)

En el presente trabajo se describen los primeros restos de un cánido en el Pleistoceno inferior de la Sierra de Quibas (Abanilla, Murcia), ampliándose la escasa representación de carnívoros en el yacimiento. Son atribuidos a la especie Vulpes praeglacialis, zorro típico del Pleistoceno inferior, en función de su reducido tamaño y del escaso desarrollo del dentículo posterior del p3.We describe the first remains of Canidae from the Lower Pleistocene karstic locality of Quibas (Abanillas, Murcia) that increasing the representation of carnivores in this site. These fossils are identified as Vulpes praeglacialis, the typical Lower Pleistocene fox. This assignment is based on their small size and the poorly developed posterior cuspid of the p/[email protected]

Refined Multiscale Entropy Predicts Early Failure in Electrical Cardioversion of Atrial Fibrillation

[EN] Electrical cardioversion (ECV) is a well-established strategy for atrial fibrillation (AF) management. Despite its high initial effectiveness, a high relapsing rate is also found. Hence, identification of patients at high risk of early AF recurrence is crucial for a rationale therapeutic strategy. For that purpose, a set of indices characterizing fibrillatory (f-) waves have been proposed, but they have not considered nonlinear dynamics present at different timescales within the cardiovascular system. This work thus explores whether a multiscale entropy (MSE) analysis of the f-waves can improve preoperative predictions of ECV outcome. Thus, two MSE approaches were considered, i.e., traditional MSE and a refined version (RMSE). Both algorithms were applied to the main f-waves component extracted from lead V1 and entropy values were computed for the first 20 time-scales. As a reference, dominant frequency (DF) and f-wave amplitude (FWA) were also computed. A total of 70 patients were analyzed, and all parameters but FWA showed statistically significant differences between those relapsing to AF and maintaining sinus rhythm during a follow-up of 4 weeks. RMSE reported the best results for the scale 19, improving predictive ability up to an 8% with respect to DAF and FWA. Consequently, investigation of nonlinear dynamics at large time-scales can provide useful insights able to improve predictions of ECV failureThis research was funded by the projects DPI2017-83952-C3 from MINECO/AEI/FEDER EU, SBPLY/17/180501/000411 from "Junta de Castilla La Mancha" and AICO/2019/036 from "Generalitat Valenciana".Cirugeda, EM.; Calero, S.; Hidalgo, VM.; Enero, J.; Rieta, JJ.; Alcaraz, R. (2020). Refined Multiscale Entropy Predicts Early Failure in Electrical Cardioversion of Atrial Fibrillation. IEEE. 1-4. https://doi.org/10.22489/CinC.2020.369S1

Training Tests on Single Superconducting Coils of Sextupolar Correctors for LHC

The precompression of the coils is considered to be one of the most important parameters to achieve good training performance in a superconducting magnet. In order to better understand and optimise precompression, a test device has been created that allows to test individual coils in a cryostat at 4.2 K exerting a variable precompression in situ. The paper describes the design, construction and calibration of the testing device, the test instrumentation and the results of the first experiments with sextupolar coils. This work was realised in the framework of a collaboration between CERN and CEDEX/Spain

Adapted Thermodynamical Model for the Prediction of Adsorption in Nanoporous Materials

In this paper, we introduce a novel, adapted approach for computing gas adsorption properties in porous materials. We analyze the Dubinin-Polanyi's adsorption model and investigate various frameworks to estimate its required essential components. Those are linked to physicochemical properties of the adsorbates, such as the vapor saturation pressure and density in the adsorbed state. To conduct this analysis, we obtain adsorption isotherms for several metal-organic frameworks, encompassing a range of pore sizes, shapes, and chemical compositions. We then apply and evaluate multiple combinations of models for saturation pressure and density. After the evaluation of the method, we propose a working thermodynamic model for computing adsorption isotherms, which entails using the critical isochore as an approximation of the saturation pressure above the critical point and applying Hauer's method with a universal thermal expansion coefficient for density in the adsorbed state. This framework is applicable not only to simulated isotherms but also to experimental data from the literature for various molecules and structures, demonstrating robust predictive capabilities and high transferability. Our method showcases superior performance in terms of accuracy, generalizability, and simplicity compared to existing methods currently in use. For the first time, a method starting from a single adsorption curve and based on physically interpretable parameters can predict adsorption properties across a wide range of operating conditions

Limb Versus Precordial ECG Leads as Improved Predictors of Electrical Cardioversion Outcome in Persistent Atrial Fibrillation

[EN] Electrical cardioversion (ECV) is an effective and low-cost rhythm control strategy for persistent atrial fibrillation (AF). Because of its limited mid- and long-term success rates, prediction of early failure could avoid patients with reduced chance to maintain sinus rhythm (SR). To this end and due to its proximity to the right atrium, several indices characterizing atrial activity have been proposed based on lead V1. However, information from other leads has been discarded to date. Hence, this work studies how effective some common indices computed over the whole set of 12 standard ECG leads are in predicting ECV outcome. Precisely, amplitude, dominant frequency, and sample entropy were computed from the fibrillatory (f-) waves extracted for each one of 12 standard leads acquired before ECV from 58 patients in persistent AF. The classification between the patients who relapsed to AF and maintained sinus rhythm after a follow-up of 4 weeks achieved by these parameters was better from limb lead II than from V1, thus reporting improvements about 6 and 12%. As a consequence, characterization of f-waves from the more accessible limb lead II has proven to be the best choice to improve AF ECV outcome prediction from the ECG.This research was funded by the projects DPI2017-83952C3 from MINECO/AEI/FEDER EU, SBPLY/17/180501/000411 from "Junta de Castilla La Mancha" and AICO/2019/036 from "Generalitat Valenciana".Cirugeda, EM.; Calero, S.; Quesada, A.; Hidalgo, VM.; Rieta, JJ.; Alcaraz, R. (2020). Limb Versus Precordial ECG Leads as Improved Predictors of Electrical Cardioversion Outcome in Persistent Atrial Fibrillation. IEEE. 1-4. https://doi.org/10.22489/CinC.2020.373S1

Preoperative Prediction of Catheter Ablation Outcome in Persistent Atrial Fibrillation Patients through Spectral Organization Analysis of the Surface Fibrillatory Waves

Catheter ablation (CA) is a commonly used treatment for persistent atrial fibrillation (AF). Since its medium/long-term success rate remains limited, preoperative prediction of its outcome is gaining clinical interest to optimally select candidates for the procedure. Among predictors based on the surface electrocardiogram, the dominant frequency (DF) and harmonic exponential decay (g) of the fibrillatory waves ( f -waves) have reported promising but clinically insufficient results. Hence, the main goal of this work was to conduct a broader analysis of the f -wave harmonic spectral structure to improve CA outcome prediction through several entropy-based measures computed on different frequency bands. On a database of 151 persistent AF patients under radio-frequency CA and a follow-up of 9 months, the newly introduced parameters discriminated between patients who relapsed to AF and those who maintained SR at about 70%, which was statistically superior to the DF and approximately similar to g. They also provided complementary information to g through different combinations in multivariate models based on lineal discriminant analysis and report classification performance improvement of about 5%. These results suggest that the presence of larger harmonics and a proportionally smaller DF peak is associated with a decreased probability of AF recurrence after CA

Training Study on Superconducting Coils of the LHC Sextupole Corrector Magnet

A study on a single sextupole coil, working under the same conditions as the full magnet, has been made to evaluate the effect of the azimuthal pre-compression and the longitudinal pre-tension on the training of superconducting coils. A testing device has been used that allows to test individual sextupole type coils in a cryostat at 4.2 K by exerting variable pre-stresses in situ. The paper describes the tests made with this device and discusses the results obtained for different pre-stress conditions and for different central island materials, in particular G-10 and stainless steel

Multidimensional Characterization of the Atrial Activity to Predict Electrical Cardioversion Outcome of Persistent Atrial Fibrillation

[EN] European Society of Cardiology guidelines recommend electrical cardioversion (ECV) as a rhythm control strategy in persistent atrial fibrillation (AF). Although ECV initially restores sinus rhythm (SR) in almost every patient, mid- and long-term AF recurrence rates are high, so that additional research is needed to anticipate ECV outcome and rationalize the management of AF patients. Although indices characterizing fibrillatory (f -) waves from surface lead V1, such as dominant frequency (DF), amplitude (FWA), and entropy, have reported good results, they discard the spatial information from the remaining leads. Hence, this work explores whether a multidimensional characterization approach of these parameters can improve ECV outcome prediction. The obtained results have shown that multidimensional FWA reported more balanced values of sensitivity and specificity, although the discriminant ability was similar in both cases. For DF, a similar outcome was also obtained. In contrast, multivariate entropy overcome discriminant ability of its univariate version by 5%, rightly anticipating result in more than 80% of ECV cases. Therefore, multidimensional entropy analysis seems to be able to quantify novel dynamics in the f-waves, which lead to a better ECV outcome predictionThis research was funded by the projects DPI2017-83952C3 from MINECO/AEI/FEDER EU, SBPLY/17/180501/000411 from "Junta de Castilla La Mancha" and AICO/2019/036 from "Generalitat Valenciana"Cirugeda, EM.; Calero, S.; Plancha, E.; Enero, J.; Rieta, JJ.; Alcaraz, R. (2020). Multidimensional Characterization of the Atrial Activity to Predict Electrical Cardioversion Outcome of Persistent Atrial Fibrillation. IEEE. 1-4. https://doi.org/10.22489/CinC.2020.377S1