Medidas de propiedades dieléctricas de materiales de construcción utilizando una guía rectangular

A set of measurements of electromagnetic properties of building materials is presented in this work. The method is based on an open-ended rectangular waveguide that radiates into the material under study. Measurements were done by using two waveguides with different size for obtaining the results in two ranges of frequencies. The values of the dielectric constant are deduced from the measured reflection coefficient or admittance of the waveguide radiating into the material. A relatively simple model can be used to deduce the values of the dielectric constant from the experimental data. This method can be used for other type of materials and its main advantage is the non-destructive character and the ease implementation

Medidas de propiedades dieléctricas de materiales de construcción mediante elipsometría

A set of measurements of electromagnetic properties of building materials is presented in this work. The method is based on the measurement of the polarization state of the reflected signal from the material under study at a fixed angle of incidence. From the measured data, by using the Fresnel equations, it has been obtained the dielectric constant. Measurements were done by using two horn antennas at the frequency of 9 GHz. The obtained results are compared with the free space reflexion and transmission Fresnel method and other reflection methods based on a conductor waveguide. The method explained in this work can be used for other type of materials and its main advantage is the non-destructive character and the ease implementation

Operational considerations to improve total ozone measurements with a Microtops II ozone monitor

A Microtops II 'ozone monitor' with UV channels centered at 305.5, 312.5, and 320 nm has been used routinely in six experimental campaigns carried out in several geographic locations and seasons, covering latitudes from 35 to 68° N during the last ten years (2001-2011). The total ozone content is retrieved by Microtops II by using different combinations (Channel I, 305.5/312.5 nm; Channel II, 312.5/320 nm; and Channel III, 305.5/312.5/320 nm) of the signals at the three ultraviolet wavelengths. The long-term performance of the total ozone content determination has been studied taking into account the sensitivities to the calibration, airmass, temperature and aerosols. When a calibration was used and the airmass limit was fixed to 3, the root mean square deviations of the relative differences produced by Microtops II with respect to several Brewers are 0.9, 2, and 2% respectively for the Channel I, Channel II, and Channel III retrieval. The performance of the Microtops retrieval has been stable during the last ten years. Channel I represents the best option to determine the instantaneous total ozone content. Channels II and III values appear weakly sensitive to temperature, ozone content, and aerosols. Channel II is more stable than Channel I for airmasses larger than 2.6. The conclusions do not show any dependence on latitude and season

One and Two-Step In Vitro-In Vivo Correlations Based on USP IV Dynamic Dissolution Applied to Four Sodium Montelukast Products

Montelukast is a weak acid drug characterized by its low solubility in the range of pH 1.2 to 4.5, which may lead to dissolution-limited absorption. The aim of this paper is to develop an in vivo predictive dissolution method for montelukast and to check its performance by establishing a level-A in vitro-in vivo correlation (IVIVC). During the development of a generic film-coated tablet formulation, two clinical trials were done with three different experimental formulations to achieve a similar formulation to the reference one. A dissolution test procedure with a flow-through cell (USP IV) was used to predict the in vivo absorption behavior. The method proposed is based on a flow rate of 5 mL/min and changes of pH mediums from 1.2 to 4.5 and then to 6.8 with standard pharmacopoeia buffers. In order to improve the dissolution of montelukast, sodium dodecyl sulfate was added to the 4.5 and 6.8 pH mediums. Dissolution profiles in from the new method were used to develop a level-A IVIVC. One-step level-A IVIVC was developed from dissolution profiles and fractions absorbed obtained by the Loo–Riegelman method. Time scaling with Levy’s plot was necessary to achieve a linear IVIVC. One-step differential equation-based IVIVC was also developed with a time-scaling function. The developed method showed similar results to a previously proposed biopredictive method for montelukast, and the added value showed the ability to discriminate among different release rates in vitro, matching the in vivo clinical bioequivalence results

Exposing and Overcoming Limitations of Clinical Laboratory Tests in COVID-19 by Adding Immunological Parameters; A Retrospective Cohort Analysis and Pilot Study

BackgroundTwo years since the onset of the COVID-19 pandemic no predictive algorithm has been generally adopted for clinical management and in most algorithms the contribution of laboratory variables is limited. ObjectivesTo measure the predictive performance of currently used clinical laboratory tests alone or combined with clinical variables and explore the predictive power of immunological tests adequate for clinical laboratories. Methods: Data from 2,600 COVID-19 patients of the first wave of the pandemic in the Barcelona area (exploratory cohort of 1,579, validation cohorts of 598 and 423 patients) including clinical parameters and laboratory tests were retrospectively collected. 28-day survival and maximal severity were the main outcomes considered in the multiparametric classical and machine learning statistical analysis. A pilot study was conducted in two subgroups (n=74 and n=41) measuring 17 cytokines and 27 lymphocyte phenotypes respectively. Findings1) Despite a strong association of clinical and laboratory variables with the outcomes in classical pairwise analysis, the contribution of laboratory tests to the combined prediction power was limited by redundancy. Laboratory variables reflected only two types of processes: inflammation and organ damage but none reflected the immune response, one major determinant of prognosis. 2) Eight of the thirty variables: age, comorbidity index, oxygen saturation to fraction of inspired oxygen ratio, neutrophil-lymphocyte ratio, C-reactive protein, aspartate aminotransferase/alanine aminotransferase ratio, fibrinogen, and glomerular filtration rate captured most of the combined statistical predictive power. 3) The interpretation of clinical and laboratory variables was moderately improved by grouping them in two categories i.e., inflammation related biomarkers and organ damage related biomarkers; Age and organ damage-related biomarker tests were the best predictors of survival, and inflammatory-related ones were the best predictors of severity. 4) The pilot study identified immunological tests (CXCL10, IL-6, IL-1RA and CCL2), that performed better than most currently used laboratory tests. ConclusionsLaboratory tests for clinical management of COVID 19 patients are valuable but limited predictors due to redundancy; this limitation could be overcome by adding immunological tests with independent predictive power. Understanding the limitations of tests in use would improve their interpretation and simplify clinical management but a systematic search for better immunological biomarkers is urgent and feasible

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Desarrollo de herramientas metodológicas para incorporar contenidos de ciencia al aula y su valoración económica

La ciencia y la tecnología juegan un papel fundamental en nuestra sociedad. En este sentido, la ciudadanía parece necesitar unos conocimientos básicos que le permitan responder de manera autónoma a multitud de situaciones, tanto a nivel personal como social (Kolstø et al., 2006). Este requisito, conocido en la literatura como alfabetización científica, lleva siendo uno de los objetivos de la educación en las últimas décadas (Hodson, 2003; Feinstein, 2011). Sin embargo, parece que su consecución presenta algunos problemas. Una de las causas de estas dificultades parece ser la falta de conexión entre los contenidos que se trabajan en las clases y el día a día del ciudadano. Respecto a esto, una solución ampliamente citada en la literatura es contextualizar el aprendizaje, relacionando los contenidos trabajados en clase con escenarios cotidianos y familiares para el alumnado (Clegg & Kolodner, 2014). El proyecto pretendía que nuestros estudiantes llevasen a cabo un análisis de los contextos con contenidos científico-económicos y promovieran su utilización en el aula y en su futuro profesional. Es decir, formar a nuestros profesionales para que pudieran detectar e incorporar entre sus competencias la capacidad de conectar lo aprendido en las asignaturas con las necesidades sociales. En concreto, el proyecto tenía, en base a los problemas detectados en la percepción de la ciencia y en la formación de los ciudadanos, dos grandes tipos de objetivos: Objetivos relacionados con la percepción de los conocimientos científico-tecnológicos y su valoración económica (Ezquerra, Fernández-Sánchez, Cabezas, 2013; Ezquerra, Fernandez-Sanchez, 2014; Ezquerra, Fernandez-Sanchez, Magaña, 2015; 2016; Ezquerra, Fernandez-Sanchez, Magaña & Mingo, 2017): • Identificar en qué situaciones los ciudadanos, en su vida cotidiana, están en presencia de contenidos científicos o tecnológicos. • Determinar de qué modo llegan al ciudadano estos contenidos, con qué intensidad, cómo son propuestos, cómo son percibidos... • Analizar el modo en que podemos otorgar a estos contenidos una valoración económica. Objetivos educativos que se integran dentro de las asignaturas: • Analizar las correspondencias entre los currículos oficiales y los contenidos presentes en el entorno del ciudadano (Ezquerra, Fernandez-Sanchez, Magaña Ramos, 2015; Ezquerra y Magaña, 2016). • Introducir a los estudiantes en una propuesta de aprendizaje basada en la indagación (Rivero et al., 2013; Ezquerra, De Juanas, Martín del Pozo, 2015). • Valorar las estrategias y competencias de los futuros docentes para vincular sus conocimientos con la realidad circundante (De Juanas et al., 2012). • Analizar las actividades que los estudiantes propongan para identificar los contenidos de ciencia y estudiar su valoración económica

Changes in digestive enzymes activities during the initial ontogeny of wolf cichlid, Parachromis dovii (Perciformes: Cichlidae)

Wolf cichlid, Parachromis dovii, is a species with a high potential for aquaculture in Central America; however, the knowledge of the digestive physiology in larvae period is limited. For these reason, this study evaluated the changes on digestive enzymes (alkaline and acid proteases, trypsin, chymotrypsin, aminopeptidase, carboxypeptidase, lipases, amylases, and phosphatases) during early ontogeny by biochemical analysis. All digestive enzymes were detected at first feeding (6 days after hatching, DAH, 9.49 mm, 168 degree-days DD). Afterwards all enzymes reached two main peaks in activity at 14 or 22 DAH (15.10 mm, 364 DD and 20.83 mm, 550 DD, respectively). Later, there was a gradual decrease in activity for trypsin and acid and alkaline phosphatases until reach the lowest values at 41 DAH. In the case of acid proteases, chymotrypsin, aminopeptidase, carboxypeptidase, lipase and amylase, all activities reached their maximum values at the end of the larval period, except for alkaline proteases, which showed the maximum value at 14 DAH (15.10 mm, 364 DD). Parachromis dovii larvae have an early capability to hydrolyze exogenous food, agreeing with other carnivorous neotropical cichlid species, for this reason we proposed that the weaning process could begin at 14 DAH.El guapote lagunero (Parachromis dovii) es una especie con un alto potencial para la acuicultura en la región de América Central; sin embargo, existe un conocimiento limitado sobre la capacidad digestiva en el periodo larval. Por este motivo, este estudio evaluó los cambios de las enzimas digestivas (proteasas alcalinas y ácidas, tripsina, quimotripsina, aminopeptidasa, carboxipeptidasa, lipasas, amilasas y fosfatasas) durante la ontogenia temprana mediante análisis bioquímico. Todas las enzimas digestivas analizadas se detectaron en la primera alimentación (6 días después de la eclosión, DAH, 9.49 mm, 168 día-grados DD). Después, todas las enzimas alcanzaron dos picos máximos a los 14 o 22 DAH (15.10 mm, 364 DD and 20.83 mm, 550 DD, respectivamente). Después las actividades tripsina, fosfatasas ácidas y alcalina disminuyeron a sus valores más bajos a los 41 DAH. En el caso de las proteasas ácidas y alcalinas, quimotripsina, aminopeptidasa, carboxipeptidasa, lipasa y amilasa, los niveles de actividad aumentaron y alcanzaron su máximo valor al final del período larvario, excepto las proteasas alcalinas, que mostraron su máximo valor a los 14 DAH (15.10 mm, 364 DD). Las larvas de P. dovii tienen una capacidad temprana para hidrolizar alimentos exógenos, lo que concuerda con otras especies de cíclidos neotropicales carnívoros, por lo que proponemos que el proceso de destete inicie a los 14 DAH.Universidad Juárez Autónoma de Tabasco, MéxicoUniversidad Nacional, Costa RicaEscuela de Ciencias Biológica

A multi-instrument approach for characterizing the atmospheric aerosol optical thickness during the STAARTE/DAISEX-99 campaign.

This work deals with the retrieval of the aerosol optical thickness (AOT) needed to carry out the atmospheric correction of remote sensing data measured in Barrax (Spain) on 4 June 1999 in the framework of 1999 Digital Airbone Imaging Spectrometer Experiment (DAISEX'99). The AOT was estimated through three approaches based on: spectral extinction of direct solar irradiance at ground level, airborne nephelometer measurements at different altitudes, and backscatter lidar in the lower troposphere. We found extremely low AOT values due to a cold Atlantic front that swept across the Iberian Peninsula from west to east producing light rain over the test area on 2 June 1999. The results were solar irradiance extinction: 0.085±0.018; nephelometer: 0.063±0.020; lidar: 0.083±0.030. Nephelometer- and lidar-derived values account for both extinction and absorption, assuming a single scattering albedo value of 0.90. Errors values include measurements and retrieval uncertainties as well as statistical variability

Optimization of the molecular diagnosis of the acute hepatitis E virus infection

To evaluate the diagnostic value of the combination of two broad-range PCR assays targeting two different and conserved regions of the viral genome for the diagnosis of acute Hepatitis E virus (HEV) infection. Patients with acute hepatitis were prospectively recruited. In all, HEV-IgM antibodies were tested together with evaluation of HEV viraemia by two PCR assays (ORF3 and ORF1). The number of individuals exhibiting negative IgM antibody results but carrying viral RNA was calculated by each PCR assay. Four-hundred and seventy individuals were included, of whom 145 (30.8%) were diagnosed as having acute HEV. Of them, 122 (84.1%) exhibited HEV-IgM antibodies, and 81 (55.8%) had detectable viral RNA for at least one PCR. Using the ORF3 molecular assay, 70 (48.3%) individuals were identified with HEV infection. When the ORF1 molecular assay was applied, 49 (33.8%) individuals were identified. The ORF3 assay detected viral RNA in 32 patients not detected by the ORF1 assay. In contrast, the ORF1 assay could amplify viral RNA in 11 patients who were not detected by the ORF3 assay. The parallel use of two broad-range PCR assays significantly increased the performance of the molecular diagnosis of HEV