Optical sensing in microchip capillary electrophoresis by femtosecond laser written waveguides

Capillary electrophoresis separation in an on-chip integrated microfluidic channel is typically monitored with bulky, bench-top optical excitation/detection instrumentation. Optical waveguides allow confinement and transport of light in the chip directing it to a small volume of the microfluidic channel and collecting the emitted/transmitted radiation. However, the fabrication of optical waveguides or more complex photonic components integrated with the microfluidic channels is not a straightforward process, since it requires a localized increase of the refractive index of the substrate.\ud Recently, a novel technique has emerged for the direct writing of waveguides and photonic circuits in transparent glass substrates by focused femtosecond laser pulses.\ud In this work we demonstrate the integration of femtosecond laser written optical waveguides into a commercial microfluidic chip. We fabricate high quality waveguides intersecting the microchannels at arbitrary positions and use them to optically address with high spatial selectivity their content. In particular, we apply our technique to integrate optical detection in microchip capillary electrophoresis. Waveguides are inscribed at the end of the separation channel in order to optically excite the different plugs reaching that point; fluorescence from the labelled biomolecules crossing the waveguide output is efficiently collected at a 90° angle by a high numerical aperture optical fiber. The sensitivity of the integrated optical detection system was first evaluated filling the chip with a dye solution, obtaining a minimum detectable concentration of 40 pM. \ud After dynamic coating of the microchannels with an EPDMA polymer we demonstrate electrophoresis of an oligonucleotide plug with concentration down to 1 nM and wavelength-selective monitoring of on-chip separation of three fluorescent dyes. Work is in progress on separation and detection of fluorescent-labeled DNA fragments, targeting specific, diagnostically relevant regions of a template DNA, for application to the detection of chromosome aberrations

Integration of femtosecond laser written waveguides for optical detection in microfluidic chips

Optical waveguides have been fabricated focusing femtosecond laser pulses into a commercial microfluidic chip. The waveguides intersect the channels and are used to optically excite their content. Fluorescence from the optically addressed volume is efficiently collected by a fiber, resulting in an highly compact and portable setup

A 5LCHB Inverter for PV transformerless applications with reduced leakage ground current

Transformerless inverters for photovoltaic systems are widely used as it features low cost, volume, and weight. Thus, in recent years, its study has been of great interest to the research community. In this paper a transformerless cascade multilevel inverter for photovoltaic applications with leakage ground current compensation capability is presented. The proposed solution involves a second-order LC output filter with a particular connection, which is referred to as the DC-link-tied LC output filter. This solution is aimed to deal with the leakage-ground current issue, regardless of the considered PWM strategy. The mathematical model of the system involving such a particular LC output passive filter configuration is presented, out of which, both the differential-mode and the common-mode models are obtained. These models are used to explain the leakage-ground current improvement of the proposed DC-link-tied LC output filter. This hardware solution is evaluated under different modulation schemes to contrast the converter output response and the leakage-ground current performance. Finally, simulation and experimental results are performed using a 1 kW academic prototype to assess the performance of the proposed DC-link-tied LC output filter used in a transformerless inverter application.Peer ReviewedObjectius de Desenvolupament Sostenible::7 - Energia Assequible i No ContaminantObjectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats SosteniblesPostprint (published version

Analysis of the oscillations induced by a supersonic jet applied to produce nanofibers

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGHigh-performance fibers are key components for enhancing the mechanical properties of composite materials. The development of high strength nanofibers augurs the production of new nano-composites with outstanding features. However, the robust production of continuous glass nanofibers that can be feasible processed for efficiently manufacturing nanocomposites is still challenging. Recently, Cofiblas (Continuous Fiberizing by Laser melting and Supersonic dragging) was demonstrated as a technique capable of producing continuous glass nanofibers with unlimited length. Cofiblas process has some similarities with the widely known melt blowing technique for the production of polymeric fibers. In both techniques, the design of the gas nozzle is key to ensure the feasibility of the process since the turbulences of the gas jet may induce strong whipping of the filament. This paper gives novel experimental evidences on the correlation of the supersonic gas jet instabilities with the oscillation of the filament in the melt-blowing and Cofiblas processes, relating these oscillations with the presence of shock waves and unsteadiness in the flow, and gives valuable insight into the use of supersonic jets in the melt blowing process as an effective approach for the formation of nanofibers. A thin 3D-axisymmetric model in OpenFOAM® was put to test by comparing the performance of different solvers which were validated by flow visualization of the exit jet using digital holography (DH). In order to perform a realistic and thorough validation, we simulated the optical measurements of the flow from the CFD simulations of the mass density by Abel transform and numerical differentiation. The application of digital holography as the flow visualization technique makes possible both a precise validation of the density maps obtained from the Abel transformation of the 2D-alike results, and the analysis of the shockwave pattern in the air jet. Conversely, the numerical reconstruction of time-averaged holograms is employed to detect unsteadiness in the flow and to analyze the fiber oscillation, which is essential to assess the stability of the process. Lastly, the analysis and comparison of the vibration of the filament using the basic design and the optimized nozzle demonstrates a clear influence of the shock waves and flow unsteadiness in the stability of the filament.Agencia Estatal de Investigación | Ref. PGC2018-094900-B-I00Xunta de Galicia | Ref. ED431C 2019/23Ministerio de Universidades | Ref. FPU20/0311

Dynamical Patterns of Cattle Trade Movements

Despite their importance for the spread of zoonotic diseases, our understanding of the dynamical aspects characterizing the movements of farmed animal populations remains limited as these systems are traditionally studied as static objects and through simplified approximations. By leveraging on the network science approach, here we are able for the first time to fully analyze the longitudinal dataset of Italian cattle movements that reports the mobility of individual animals among farms on a daily basis. The complexity and inter-relations between topology, function and dynamical nature of the system are characterized at different spatial and time resolutions, in order to uncover patterns and vulnerabilities fundamental for the definition of targeted prevention and control measures for zoonotic diseases. Results show how the stationarity of statistical distributions coexists with a strong and non-trivial evolutionary dynamics at the node and link levels, on all timescales. Traditional static views of the displacement network hide important patterns of structural changes affecting nodes' centrality and farms' spreading potential, thus limiting the efficiency of interventions based on partial longitudinal information. By fully taking into account the longitudinal dimension, we propose a novel definition of dynamical motifs that is able to uncover the presence of a temporal arrow describing the evolution of the system and the causality patterns of its displacements, shedding light on mechanisms that may play a crucial role in the definition of preventive actions

Dynamical Patterns of Cattle Trade Movements

Despite their importance for the spread of zoonotic diseases, our understanding of the dynamical aspects characterizing the movements of farmed animal populations remains limited as these systems are traditionally studied as static objects and through simplified approximations. By leveraging on the network science approach, here we are able for the first time to fully analyze the longitudinal dataset of Italian cattle movements that reports the mobility of individual animals among farms on a daily basis. The complexity and inter-relations between topology, function and dynamical nature of the system are characterized at different spatial and time resolutions, in order to uncover patterns and vulnerabilities fundamental for the definition of targeted prevention and control measures for zoonotic diseases. Results show how the stationarity of statistical distributions coexists with a strong and non-trivial evolutionary dynamics at the node and link levels, on all timescales. Traditional static views of the displacement network hide important patterns of structural changes affecting nodes' centrality and farms' spreading potential, thus limiting the efficiency of interventions based on partial longitudinal information. By fully taking into account the longitudinal dimension, we propose a novel definition of dynamical motifs that is able to uncover the presence of a temporal arrow describing the evolution of the system and the causality patterns of its displacements, shedding light on mechanisms that may play a crucial role in the definition of preventive actions

ALDH4A1 is an atherosclerosis auto-antigen targeted by protective antibodies

Cardiovascular disease (CVD) is the leading cause of mortality in the world, with most CVD-related deaths resulting from myocardial infarction or stroke. The main underlying cause of thrombosis and cardiovascular events is atherosclerosis, an inflammatory disease that can remain asymptomatic for long periods. There is an urgent need for therapeutic and diagnostic options in this area. Atherosclerotic plaques contain autoantibodies, and there is a connection between atherosclerosis and autoimmunity. However, the immunogenic trigger and the effects of the autoantibody response during atherosclerosis are not well understood. Here we performed high-throughput single-cell analysis of the atherosclerosis-associated antibody repertoire. Antibody gene sequencing of more than 1,700 B cells from atherogenic Ldlr and control mice identified 56 antibodies expressed by in-vivo-expanded clones of B lymphocytes in the context of atherosclerosis. One-third of the expanded antibodies were reactive against atherosclerotic plaques, indicating that various antigens in the lesion can trigger antibody responses. Deep proteomics analysis identified ALDH4A1, a mitochondrial dehydrogenase involved in proline metabolism, as a target antigen of one of these autoantibodies, A12. ALDH4A1 distribution is altered during atherosclerosis, and circulating ALDH4A1 is increased in mice and humans with atherosclerosis, supporting the potential use of ALDH4A1 as a disease biomarker. Infusion of A12 antibodies into Ldlr mice delayed plaque formation and reduced circulating free cholesterol and LDL, suggesting that anti-ALDH4A1 antibodies can protect against atherosclerosis progression and might have therapeutic potential in CVD.Ministerio de Economía y Competitividad (SVP-2014-068289); P.D. was supported by an AECC grant (AIO 2012, Ayudas a Investigadores en Oncología 2012); A.S.-B. is a Juan de la Cierva researcher (IJC2018-035279-I); I.M.-F. was a fellow of the research training program funded by Ministerio de Economía y Competitividad (SVP-2014-068216); and A.R.R. and J.V. are supported by Centro Nacional de Investigaciones Cardiovasculares (CNIC). The project leading to these results has received funding from la Caixa Banking Foundation under the project code HR17-00247 and from SAF2016-75511-R and PID2019-106773RB-I00 grants to A.R.R. (Plan Estatal de Investigación Científica y Técnica y de Innovación 2013–201

280 one-opposition near-Earth asteroids recovered by the EURONEAR with the <i>Isaac Newton</i> Telescope

Context. One-opposition near-Earth asteroids (NEAs) are growing in number, and they must be recovered to prevent loss and mismatch risk, and to improve their orbits, as they are likely to be too faint for detection in shallow surveys at future apparitions. Aims. We aimed to recover more than half of the one-opposition NEAs recommended for observations by the Minor Planet Center (MPC) using the Isaac Newton Telescope (INT) in soft-override mode and some fractions of available D-nights. During about 130 h in total between 2013 and 2016, we targeted 368 NEAs, among which 56 potentially hazardous asteroids (PHAs), observing 437 INT Wide Field Camera (WFC) fields and recovering 280 NEAs (76% of all targets). Methods. Engaging a core team of about ten students and amateurs, we used the THELI, Astrometrica, and the Find_Orb software to identify all moving objects using the blink and track-and-stack method for the faintest targets and plotting the positional uncertainty ellipse from NEODyS. Results. Most targets and recovered objects had apparent magnitudes centered around V ~ 22.8 mag, with some becoming as faint as V ~ 24 mag. One hundred and three objects (representing 28% of all targets) were recovered by EURONEAR alone by Aug. 2017. Orbital arcs were prolonged typically from a few weeks to a few years; our oldest recoveries reach 16 years. The O−C residuals for our 1854 NEA astrometric positions show that most measurements cluster closely around the origin. In addition to the recovered NEAs, 22 000 positions of about 3500 known minor planets and another 10 000 observations of about 1500 unknown objects (mostly main-belt objects) were promptly reported to the MPC by our team. Four new NEAs were discovered serendipitously in the analyzed fields and were promptly secured with the INT and other telescopes, while two more NEAs were lost due to extremely fast motion and lack of rapid follow-up time. They increase the counting to nine NEAs discovered by the EURONEAR in 2014 and 2015. Conclusions. Targeted projects to recover one-opposition NEAs are efficient in override access, especially using at least two-meter class and preferably larger field telescopes located in good sites, which appear even more efficient than the existing surveys

Reliability and Validation of the Child Eating Behavior Questionnaire in 3- to 6-Year-Old Spanish Children

Introduction: Eating behavior is often established during the first years of life. Therefore, it is important to make a research on it to understand the relationships that children have with food and how this can contribute to prevent the development of childhood obesity. An appropriate assessment of eating behavior can be achieved using the “Child Eating Behavior Questionnaire” (CEBQ). This questionnaire has been validated in several populations and languages, but it has never been translated, adapted, and validated for Spanish children. Aim: To evaluate the reliability and internal consistency of the CEBQ questionnaire, culturally adapted and translated into Spanish (Spain), in Spanish families with children aged 3 to 6 years, as well as its association with children’s body mass index (BMI) to test its construct validity. Materials and Methods: Children between 3 and 6 years old were recruited from the ongoing MELI-POP randomized controlled clinical trial, as well as from public schools located in middle class neighborhoods of Zaragoza, Spain, to complete the sample. Sociodemographic characteristics and anthropometric measures were obtained according to standardized methods. The 35-item CEBQ questionnaire was completed twice with a time difference of 3 weeks between each response. Statistical analyses included the evaluation of internal consistency and reliability of the questionnaire, a confirmatory factor analysis, and the association between the different CEBQ scales and the children’s BMI. Results: A total of 197 children completed variables; 97 of them were boys (49.2%) and 100 girls (50.8%). Mean age of the total sample was 4.7 ± 0.9 years. There was a high test-re-test reliability of the questionnaire with values close to 1, with an average of 0.66 and a good internal consistency (Cronbach alpha with values above 0.7), so that a high reliability is established between the items in each scale. A gradual positive association was found between the score of different “pro-intake” scales of the CEBQ: “Food Responsiveness, ” “Emotional Overeating, ” and “Enjoyment of food” and the children’s BMI; at the opposite, negative associations were observed between BMI and the score of anti-intake scales “Satiety Responsiveness, ” “Slowness in Eating, ” and “Emotional Undereating.” Conclusion: The Spanish version of the CEBQ is a useful tool to assess the eating behavior of Spanish children because the high reliability and internal validity. There is a significant association between eating behavior and BMI in Spanish children. Copyright © 2022 Jimeno-Martínez, Maneschy, Moreno, Bueno-Lozano, De Miguel-Etayo, Flores-Rojas, Jurado-Castro, de Lamas, Vázquez-Cobela, Martinez-Lacruz, Portoles, Martínez, Navas-Carretero, Schröder, Fitó, Babio, Salas-Salvadó, Leis, Gil-Campos and Rupérez

Biology, Methodology or Chance? The Degree Distributions of Bipartite Ecological Networks

The distribution of the number of links per species, or degree distribution, is widely used as a summary of the topology of complex networks. Degree distributions have been studied in a range of ecological networks, including both mutualistic bipartite networks of plants and pollinators or seed dispersers and antagonistic bipartite networks of plants and their consumers. The shape of a degree distribution, for example whether it follows an exponential or power-law form, is typically taken to be indicative of the processes structuring the network. The skewed degree distributions of bipartite mutualistic and antagonistic networks are usually assumed to show that ecological or co-evolutionary processes constrain the relative numbers of specialists and generalists in the network. I show that a simple null model based on the principle of maximum entropy cannot be rejected as a model for the degree distributions in most of the 115 bipartite ecological networks tested here. The model requires knowledge of the number of nodes and links in the network, but needs no other ecological information. The model cannot be rejected for 159 (69%) of the 230 degree distributions of the 115 networks tested. It performed equally well on the plant and animal degree distributions, and cannot be rejected for 81 (70%) of the 115 plant distributions and 78 (68%) of the animal distributions. There are consistent differences between the degree distributions of mutualistic and antagonistic networks, suggesting that different processes are constraining these two classes of networks. Fit to the MaxEnt null model is consistently poor among the largest mutualistic networks. Potential ecological and methodological explanations for deviations from the model suggest that spatial and temporal heterogeneity are important drivers of the structure of these large networks