Mathematical modeling of area under the curve assessment criteria to quantify the antioxidant and pro-oxidant capacity: Coffee extracts as a case study

35 páginas, 5 figuras, 2 tablasThe development of a convenient mathematical application for testing the antioxidant and pro-oxidant capacity is essential in order to investigate potential sources of new agents and processes. In this regard, authors use the standardized values of the area under the curve of a kinetic profile of a dose-response agent, as a way to bypass the complex process of analyzing the kinetic variations of agents. In general, linear approaches are used, but such patterns frequently lead to unreliable results and misinterpretations, making it extremely difficult to compare the results from different assays. In this work, we have demonstrated the non-linearity of the dose-response area under the curve assessment criteria by means of simulations. A simple non-linear dose-response model was developed to describe the accurately response. As case study, experimental data of extracts of unroasted coffee beans from five different country-climate locations for the two most common coffee varieties (Robusta and Arabica) were obtained using the β-carotene and crocin bleaching in vitro assays. Their antioxidant capacity was analyzed in detail and compared with commercial standards. The results shows that the antioxidant capacity was greater than some of the commercial standards in terms of its maximum capacity, while when the analyses are based on rate parameters, the coffee extracts show between 6 to 40 times lower values than the standard antioxidants. In addition, to illustrate the advantages of using the standardized area units and the mathematical model developed, other more complex scenarios were recreated. We believe that the model application developed provides a simple alternative to summarize in meaningful parameters that characterize the response, it facilitates rigorous comparisons among the effects of different compounds and experimental approaches and it helps to comprehend multi-variable scenariosThe authors wish to thank CSIC (Intramural project: 200930I183) and Ministerio de Ciencia e Innovación (project CTM2010-18411, co-financed with FEDER funds by European Union) for financial support. Miguel Angel Prieto Lage was awarded one grant from the JAE predoctoral program co-financed by the CSIC and European Social Fund (ESF)Peer reviewe

Hydrolysis optimization of mannan, curdlan and cell walls from Endomyces fibuliger grown in mussel processing wastewaters

The aim of this report was to optimize the hydrolysis of the cell walls (CWs) from the yeast Endomyces fibuliger grown in mussel processing wastewaters (MPW) to establish a more accurate protocol for analyzing the composition of the monosaccharides in these CWs. Therefore, a kinetic study of CW hydrolysis and polysaccharide standards (mannan and curdlan) was performed to determine the effect of different temperatures and trifluoroacetic acid (TFA) concentrations on this process. In all cases, the experimental data were fit satisfactorily to Saeman's equation with an Arrhenius relation between rate constants and the temperature effect. Optimal conditions for curdlan and mannan hydrolysis were achieved with 70% TFA at 100 °C for 2.3 h and 50% TFA at 100 °C for 2.6 h, respectively. The best operating options for CW hydrolysis were 100 °C/70% TFA for 4.58 h, 100 °C/50% TFA for 4.08 h and 100 °C/70% TFA for 3.27 h for the maximum production of glucose, mannose and reducing sugars, respectively.Mr. Miguel Angel Prieto Lage was awarded with two grants from the Lucas Labrada and María Barbeito programs financed by the Xunta de Galicia. We wish to thank the CSIC (Intramural Project: 200930I183) and Xunta de Galicia (Programa de consolidación de unidades de investigación 2008–2010, IN845B-2010/004) for financial support.Peer reviewe

Development of Magnetostrictive Transducer Prototype for Blockage Detection on Molten Salt Pipes

In solar thermal power plants molten salt is often used to store and transport the energy that is collected during the day. The external pipe temperature is measured to activate an electric heating system if the temperature approaches the melting point. However, salt solidification cannot be completely excluded from the plant management. Once occurred, the location of a salt blockage is very complex due to the high temperature of the pipe. Therefore, when this problem arises, power plants have to stop production with the consequences in time and cost that this entails. Electro-magnetic acoustic transducers can be used as non-destructive testing systems for this application. A method for salt blockage detection is proposed that is applicable in straight sections of pipes by employing torsional guided waves that are generated with magnetostrictive transducers. The present paper deals with the transducer conception and the design of the power supply to activate it. Two alternatives are proposed and compared to determine the improvement in the amplitude/noise ratio. Finally, the experimental results show the performance of the equipment in a small prototype, thus validating the technique presented

Use of synthetic RGB images in train

Ponencia presentada en: 2010 EUMETSAT Meteorological Satellite Conference celebrada del 20-24 de septiembre de 2010 en Córdoba.This paper compares actual and synthetic (calculated) airmass RGB composites, before and after applying different corrections: (a) synthetic airmass RGB calculated with the satellite zenith angle corresponding to the pixel, versus others with fixed zenith angles (0º, 15º, 30º, 45º, 60º and 75º), to observe the blue shift close to the disk boundary due to a longer atmospheric path for the signal in oblique views, (b) Synthetic airmass RGB in areas of sinking tropopause with ozone intrusion for different values in the ozone concentration and humidity. The synthetic RGB for MSG are based on the use of the ECMWF model with RTTOV package and the METEOSAT Second Generation coefficients. Also synthetic MTG-IRS sounder RGBs have been generated. Based on the use of the RTTOV package with the IASI coefficients for one GRIB file of the ECMWF model, synthetic IASI RTTOV radiances are converted to synthetic MTG-IRS RTTOV brightness temperatures (BT). After one selection of the most adequate MTG-IRS brightness temperatures (BTs), two MTG-sounder synthetic RGBs are created. This is a proving ground experiment for the MTG sounder era

Li-Po Battery Charger Based on the Constant Current/Voltage Parallel Resonant Converter Operating in ZVS

Battery requirements for electrical vehicles are continuously becoming more demanding in terms of energy density and reliability. Nowadays, batteries for drones must be able to supply 100 A for 15 min, not to mention the specifications required for batteries in electrical vehicles. These specifications result in more stringent specifications for battery chargers. They are required to be more efficient, flexible, and, as with any another power equipment, to have reduced size and weight. Since the parallel resonant converter can operate as a current source and as a voltage source, this paper presents a battery charger power stage for lithium ion polymer batteries, based on the above topology, operating in zero voltage switching mode, and implementing frequency and duty cycle control

Environmental heterogeneity, bird-mediated directed dispersal, and oak woodland dynamics in Mediterranean Spain

Vegetation dynamics in complex landscapes depend on interactions among\ud environmental heterogeneity, disturbance, habitat fragmentation, and seed dispersal\ud processes. We explore how these features combine to affect the regional abundances and\ud distributions of three Quercus (oak) species in central Spain: Q. faginea (deciduous tree), Q.\ud ilex (evergreen tree), and Q. coccifera (evergreen shrub). We develop and parameterize a\ud stochastic patch occupancy model (SPOM) that, unlike previous SPOMs, includes\ud environmentally driven variation in disturbance and establishment. Dispersal in the model\ud is directed toward local (nearby) suitable habitat patches, following the observed seed-caching\ud behavior of the European Jay. Model parameters were estimated using Bayesian methods and\ud survey data from 12 047 plots. Model simulations were conducted to explore the importance of\ud different dispersal modes (local directed, global directed, local random, global random). The\ud SPOM with local directed dispersal gave a much better fit to the data and reproduced observed\ud regional abundance, abundance–environment correlations, and spatial autocorrelation in\ud abundance for all three species. Model simulations suggest that jay-mediated directed dispersal\ud increases regional abundance and alters species–environment correlations. Local dispersal is\ud estimated to reduce regional abundances, amplify species–environment correlations, and\ud amplify spatial autocorrelation.\ud Parameter estimates and model simulations reveal important species-specific differences in\ud sensitivity to environmental perturbations and dispersal mode. The dominant species Q. ilex is\ud estimated to be highly fecund, but on the edge of its climatic tolerance. Therefore Q. ilex gains\ud little from directed dispersal, suffers little from local dispersal, and is relatively insensitive to\ud changes in habitat cover or disturbance rate; but Q. ilex is highly sensitive to altered drought\ud length. In contrast, the rarest species, Q. coccifera, is well adapted to the climate and soils but\ud has low fecundity; thus, it is highly sensitive to changes in dispersal, habitat cover, and\ud disturbance but insensitive to altered drought length. Finally, Q. faginea is estimated to be\ud both at the edge of its climatic tolerance and to have low fecundity, making it sensitive to all\ud perturbations. Apparently, co-occurring species can exhibit very different interactions among\ud dispersal, environmental characteristics, and physiological tolerances, calling for increased\ud attention to species-specific dynamics in determining regional vegetation responses to\ud anthropogenic perturbations

A Method to Estimate the Efficacy vs. Effectiveness in Meta-Analysis of Clinical Trials with Different Adherence Scenarios: A Monte Carlo Simulation Study in Nutrition.

Randomized clinical trials (RCTs) evaluating the effectiveness of interventions to promote fruit and vegetable (FV) consumption usually report intention-to-treat (ITT) analysis as the main outcome. These analyses compare the randomly assigned groups and accept that some individuals may not follow the recommendations received in their group. The ITT analysis is useful to quantify the global effect of promoting the consumption of FV in a population (effectiveness) but, if non-adherence is significant in the RCT, they cannot estimate the specific effect in the individuals that increased their FV consumption (efficacy). To calculate the efficacy of FV consumption, a per protocol analysis (PP) would have to be carried out, in which groups of individuals are compared according to their actual adherence to FV consumption, regardless of the group to which they were assigned; unfortunately, many RCTs do not report the PP analysis. The objective of this article is to apply a new method to estimate the efficacy of Meta-analysis (MA) PP which include RCTs of effectiveness by ITT, without estimates of adherence. The method is based on generating Monte Carlo simulations of percentages of adherence in each allocation group from prior distributions informed by expert knowledge. We illustrate the method reanalyzing a Cochrane Systematic Review (SR) of RCTs on increased FV consumption reported with ITT, simulating 1000 times the estimation of a PP meta-analyses, and obtaining means and ranges of the potential PP effects. In some cases, the range of estimated PP effects was clearly more favourable than the effect calculated with the original ITT assumption, and therefore this corrected analysis must be considered when estimating the true effect of the consumption of a certain food

Hacia la consolidación de las aulas ágiles

La educación ágil está acercando a las aulas las prácticas de mayor éxito en la industria del software, permitiendo que los alumnos comiencen a asimilar una forma de trabajo ampliamente implantada y que, además, experimenten y adquieran algunas de las competencias más demandadas en el mercado de trabajo. Este artículo presenta UVAGILE, un nuevo marco de trabajo basado en Scrum que aborda la organización ágil de procesos de enseñanza-aprendizaje y que fomenta el aprendizaje incremental y la retroalimentación frecuente. Los resultados obtenidos, a partir de la implementación de cuatro aulas ágiles, avalan la efectividad de UVAGILE, tanto por la mejora de los resultados académicos como por las opiniones expresadas por los alumnos.Agile education brings the most successful practices in the software industry into the classroom. It allows our students to learn and practice a widely established framework in the labor market, but also experience and acquire some of its most-demanded soft skills. This paper presents UVAGILE, a new Scrum-based framework that organizes learning projects from an agile perspective, encouraging incremental learning and regular feedback. Our preliminary results, from four agile classrooms, show the UVAGILE effectiveness, both in terms of improved academic grades and positive feedback from participating students.Este trabajo ha sido financiado por el Proyecto de Innovación Docente No. 82 del plan PID-2019/2020 de la Universidad de Valladolid (UVa)

Preparation of marine silage of swordfish, ray and shark visceral waste by lactic acid bacteria

The goal of the present work was to study the efficacy of several lactic acid bacteria (LAB) as bio-silage inoculants of swordfish, ray and shark viscera by-products. A sterilised medium was initially used as a model system for assessing the potential of these microorganisms in batch and fed-batch cultures with re-neutralisation. In all cases, batch cultivations without re-neutralisation led to the highest production and yields of the main metabolites of LAB fermentation (lactic and acetic acids). The dynamics of these metabolites followed a conversion pattern from lactic to acetic acid with a final joint concentration over 16 g/L and final pH lower than 4.5. Both productions were modelled by means of logistic modified equations. In addition, the capability of LAB to ferment the fish visceral wastes was always high and easily reproducible. Finally, the results obtained for non-sterilised fermentations with Lactobacillus casei CECT 4043 were similar to those obtained for sterilised media, and a stable material was obtained after 72 h of culture.Peer reviewe

Modeling a multilevel converter for radiography and fluoroscopy

EPE'16 ECCE Europe, 18th European Conference on Power Electronics and Applications, 5-9 september 2016, Karsruhe, GermanyIn this paper a mathematical model for a resonant multilevel converter is presented. The topology has been conceived to be used in X-ray power supplies. The power stage has been designed to minimize the resonant current throughout the input voltage range: 400V to 750V. The inverter stage is based on the series-parallel resonant topology, LCC, to include the parasitic elements of the step-up transformer. However, the introduction of an additional magnetic coupling provides a way to modify the reactive elements depending on the output powe