10,897 research outputs found
Educação CTS e articulação entre educação não-formal e formal com recurso a um courseware didáctico
Considerando recomendações da investigação em educação em ciências e a tendência global de promoção das TIC, está em desenvolvimento um estudo de natureza qualitativa cuja finalidade é a concepção, produção, implementação e avaliação de um courseware didáctico de cariz CTS que articule contextos formais e não-formais de educação. Este courseware abordará a eficiência energética e fontes energéticas renováveis e procurará incluir, particularmente para crianças dos 8 aos 12 anos, uma articulação entre actividades escolares e o espaço Jardim de Ciência da Universidade de Aveiro. A avaliação será realizada pela caracterização das concepções CTS, práticas didáctico-pedagógicas, e recurso a meios de educação não-formal por um grupo de professores. Algumas das actividades em desenvolvimento serão objecto de apresentação nesta comunicação
Adsorption of proteins to thin-films of PDMS and its effect on the adhesion of human endothelial cells
This paper describes a simple and inexpensive procedure to produce thin-films of poly(dimethylsiloxane). Such films were characterized by a variety of techniques (ellipsometry, nuclear magnetic resonance, atomic force microscopy, and goniometry) and used to investigate the adsorption kinetics of three model proteins (fibrinogen, collagen type-I, and bovine serum albumin) under different conditions. The information collected from the protein adsorption studies was then used to investigate the adhesion of human dermal microvascular endothelial cells. The results of these studies suggest that these films can be used to model the surface properties of microdevices fabricated with commercial PDMS. Moreover, the paper provides guidelines to efficiently attach cells in BioMEMS devices.Fil: Chumbimuni Torres, Karin Y.. The University of Texas at San Antonio; Estados UnidosFil: Coronado, Ramon E.. The University of Texas at San Antonio; Estados UnidosFil: Mfuh, Adelphe M.. The University of Texas at San Antonio; Estados UnidosFil: Castro Guerrero, Carlos. The University of Texas at San Antonio; Estados UnidosFil: Silva, María Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Biología Agrícola de Mendoza. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto de Biología Agrícola de Mendoza; ArgentinaFil: Negrete, George R.. The University of Texas at San Antonio; Estados UnidosFil: Bizios, Rena. The University of Texas at San Antonio; Estados UnidosFil: Garcia, Carlos D.. The University of Texas at San Antonio; Estados Unido
Non-Aqueous Biocatalysis in Homogeneous Solvent Systems
Enzymes are highly specific catalysts that typically function in aqueous solvents. However, many enzymes retain their catalytic activities at high concentrations in non- aqueous environments, including neat hydrophilic organic solvents. In fact, enzymes can be used to carry out reactions in organic solvents that are not possible in aqueous systems. Therefore, biocatalysis in homogenous non-aqueous solvents offers possibilities for producing useful chemicals and several synthetic reactions have already been developed using this type of system. The current review discusses factors that influence enzyme catalysis in non-aqueous solvents such us water content, solvent concentration, interaction of solvent with protein structure, stability and activity. Also, new strategies for non-conventional biocatalysis using extremophiles and ionic solvents are mentioned
Estudio comparativo de los parámetros calidad de la leche, características tecnológicas y producción quesera de la Raza Merina de Grazalema frente al cruce con razas foráneas
En los últimos años se están incorporando masivamente
en España, en general, y en Andalucía, en
particular, razas ovinas foráneas de aptitud lechera,
fundamentalmente las razas Assaf, Awassi y Lacaune.
Su introducción está fomentando, asimismo, la realización
de cruces indiscriminados con nuestras razas
ovinas autóctonas, de aptitud lechera pero de menor
especialización, al menos cuantitativamente (Casas et
al., 2005).
El objetivo de este estudio ha sido analizar en dos
grupos de animales de un mismo rebaño (ovejas puras
de raza Merina de Grazalema, y ovejas cruzadas
Merina de Grazalema x Awassi) las características de
la producción lechera, y proceder a la elaboración de
quesos para estudiar las posibles diferencias tecnológicas
de los quesos derivados de ambas elaboraciones.
A través del mismo se ha comprobado una mayor producción
lechera de las ovejas cruzadas (167.35±13.20
kg frente a 136.84±4.25 kg) pero con un porcentaje de
grasa (6.25±0.34 % frente a 8.27±0.22 %), proteína
(4.71±0.14 % frente a 5.80±0.09 %) y extracto seco
(10.97±0.46 % frente a 14.07±0.28 %), estadísticamente
inferior. En cuanto a los parámetros de aptitud tecnológica,
los valores de tiempo de coagulación medio (24.70±0.77
minutos), dureza media (dureza del coágulo a los 30 minutos)
de 25.03±2.27 mm, y el rendimiento en cuajada
(327.50±5.70 g/l), mostraron cifras inferiores a las referenciadas
por Casas et al. (2005) para la raza ovina Merina de
Grazalema. Finalmente, la velocidad de endurecimiento
resultó mayor a los valores obtenidos en el trabajo citado
anteriormente (4.59±0.54 min.). Por otro lado, estos mismos
parámetros mostraron valores inferiores en el tiempo
de coagulación (19.60±0.62 minutos), velocidad de endurecimiento
(3.97±0.38 min.) y rendimiento en cuajada
(290.55±6.67), mientras que la dureza media (32.85±2.03
mm) fue superior en las ovejas cruzadas, respecto a los
valores encontrados en esta misma explotación para los
animales puros.
Como consecuencia de todo ello, el rendimiento quesero
real fue del 30.25 % para las ovejas puras frente al
23.70 % de las cruzadas.
Esto determina que la producción quesera real que
se obtiene por oveja pura, sea superior al de la cruzada
(41.38 kg queso fresco/lactación frente a los 39.70 de la
cruzada)
Two short mass-loss events that unveil the binary heart of Minkowski's Butterfly Nebula
Studying the appearance and properties of bipolar winds is critical to
understand the stellar evolution from the AGB to the planetary nebula (PN)
phase. Many uncertainties exist regarding the presence and role of binary
stellar systems, mainly due to the deficit of conclusive observational
evidences. We investigate the extended equatorial distribution around the early
bipolar planetary nebula M 2-9 ("Minkowski's Butterfly Nebula") to gather new
information on the mechanism of the axial ejections. Interferometric millimeter
observations of molecular emission provide the most comprehensive view of the
equatorial mass distribution and kinematics in early PNe. Here we present
subarcsecond angular-resolution observations of the 12CO J=2-1 line and
continuum emission with the Plateau de Bure interferometer. The data reveal two
ring-shaped and eccentric structures at the equatorial basis of the two coaxial
optical lobes. The two rings were formed during short mass-loss episodes (~ 40
yr), separated by ~ 500 yr. Their positional and dynamical imprints provide
evidence of the presence of a binary stellar system at the center, which yields
critical information on its orbital characteristics, including a mass estimate
for the secondary of ~< 0.2 \ms. The presence of a stellar system with a
modest-mass companion at the center of such an elongated bipolar PN strongly
supports the binary-based models, because these are more easily able to explain
the frequent axisymmetric ejections in PNe.Comment: 8 page
Educação cts e articulação entre educação não-formal e formal com recurso a um courseware didáctico
Considerando recomendações da investigação em educação em ciências e a tendência global de promoção das TIC, está em desenvolvimento um estudo de natureza qualitativa cuja finalidade é a concepção, produção, implementação e avaliação de um courseware didáctico de cariz CTS que articule contextos formais e não-formais de educação. Este courseware abordará a eficiência energética e fontes energéticas renováveis e procurará incluir, particularmente para crianças dos 8 aos 12 anos, uma articulação entre actividades escolares e o espaço Jardim de Ciência da Universidade de Aveiro. A avaliação será realizada pela caracterização das concepções CTS, práticas didáctico-pedagógicas, e recurso a meios de educação não-formal por um grupo de professores. Algumas das actividades em desenvolvimento serão objecto de apresentação nesta comunicação
Growth of out-of-plane standing MoTe2(1-x)Se2x/MoSe2 composite flake films by sol–gel nucleation of MoOy and isothermal closed space telluro-selenization
This study describes the sol–gel processing of MoOy on Si (1 0 0) to subsequently achieve out-of-plane MoTe2/MoSe2 flake composite films by an isothermal closed space vapor transformation. The oxide precursor films have been prepared from a Mo isopropoxide solution in isopropanol and acid catalysis induced by HCl. Thermal annealing at 200, 400 and 600 °C enhanced the condensation after xerogel formation. An x-ray absorption analysis demonstrates that films condensed at 200 °C are at an intermediate chemical state between MoO3 and MoO2. To achieve MoTe2/MoSe2 composite films, the precursor oxide films were reduced in H2 and exposed to the chalcogenides by isothermal closed space vapor transport at 600 °C. The multilayered nanocomposite films grow with an out-of-plane flake-like structure and an evident integration of Se in the MoTe2 phase according to a MoTe2(1-x)Se2x alloy, with an estimation of x of 0.25. The alloy and the orientation of the flakes are consistent with the bands present in the Raman spectrum. These films are attractive for applications requiring high surface area interfaces favoring gas or ion exchange reactions with transition metal dichalcogenidesThe current research was funded by grant CTQ2017-84309-C2-2-R from Ministerio de Ciencia e Innovación (Spain). The authors acknowledge the ESRF and the Ministerio de Ciencia, Innovación y Universidades (Spain), for provision of synchrotron radiation facilities and the Consejo Superior de Investigaciones Científicas (Spain) financial support for the operation of the beamline under Grant No. PIE 2010 6 OE 01
Statistical Analysis of 100 Gbps per Wavelength SWDM VCSEL-MMF Data Center Links on a Large Set of OM3 and OM4 Fibers
We present a detailed statistical study on achievable reach of 100 Gbps data center optical links based on vertical cavity surface emitting lasers (VCSEL) and multimode fibers (MMF). Based on the characterization of the spectral and spatial properties of eight lasers and of the modal and dispersion behavior of a large set of 20233 OM3 and OM4 modeled fibers (obtained by properly extending an initial set of 500 measured fibers), we compute the resulting frequency responses of all of the VCSEL-MMF combinations. Then, we feed them to a numerical tool modeling PAM-4 transmission at 100 Gbps net bit rate per wavelength. Our model analyzes performance at distances up to 400 meters, using three different adaptive equalizers at the receiver and considering two forward error correction overheads. We show that 100 Gbps operation is feasible for 99% of the simulated links reaching up to 120 m over OM4 at 850 nm and using a decision feedback equalizer (DFE). Aggregated data rates of 200 Gbps and 400 Gbps per fiber using Shortwave Wavelength Division Multiplexing (SWDM) are achievable for 99% of the links reaching 80 m over OM4 using two wavelengths and feed-forward equalizer (FFE) and four wavelengths and maximum likelihood sequence estimation (MLSE)-based equalizer, respectively
Visceral Obesity and Metabolic Syndrome Are Associated with Well-Differentiated Gastroenteropancreatic Neuroendocrine Tumors
The determinants for gastroenteropancreatic neuroendocrine tumors (GEP-NET) recent burden are matters of debate. Obesity and metabolic syndrome (MetS) are well established risks for several cancers even though no link with GEP-NETs was yet established. Our aim in this study was to investigate whether well-differentiated GEP-NETs were associated with obesity and MetS. Patients with well-differentiated GEP-NETs (n = 96) were cross-matched for age, gender, and district of residence with a control group (n = 96) derived from the general population in a case-control study. Patients presented gastro-intestinal (75.0%) or pancreatic (22.9%) tumors, grade G1 (66.7%) or G2 (27.1%) with localized disease (31.3%), regional metastasis (16.7%) or distant metastasis (43.8%) at diagnosis, and 45.8% had clinical hormonal syndromes. MetS was defined according to Joint Interim Statement (JIS) criteria. Well-differentiated GEP-NETs were associated with MetS criteria as well as the individual components' waist circumference, fasting triglycerides, and fasting plasma glucose (p = 0.003, p = 0.002, p = 0.011 and p < 0.001, respectively). The likelihood of the association was higher when the number of individual MetS components was greater than four. MetS and some individual MetS components including visceral obesity, dyslipidemia, and increased fasting glucose are associated with well-differentiated GEP-NET. This data provides a novel insight in unraveling the mechanisms leading to GEP-NET disease.This project was funded by a grant from Research Center of IPO-Porto (CI-IPOP 32-2015)info:eu-repo/semantics/publishedVersio
Exercise Capacity in Children and Adolescents With Congenital Heart Disease: A Systematic Review and Meta-Analysis
Congenital heart disease (CHD) entails structural defects in the morphogenesis of the heart or its main vessels. Analyzing exercise capacity of children and adolescents with CHD is important to improve their functional condition and quality of life, since it can allow timely intervention on poor prognostic factors associated with higher risk of morbidity and mortality.To describe exercise capacity in children and adolescents with CHD compared with healthy controls.A systematic review was carried out. Randomized clinical trials and observational studies were included assessing exercise capacity through direct and indirect methods in children and adolescents between 5 and 17 years-old. A sensitive analysis was performed including studies with CHD repaired participants. Additionally, it was sub-analyzed by age range (< and ? 12 years old). Two independent reviewers analyzed the studies, extracted the data, and assessed the quality of the evidence.5619 articles were found and 21 were considered for the review. Eighteen articles used the direct exercise capacity measurement method by cardiopulmonary exercise test (CPET). The CHD group showed significant differences in peak oxygen consumption (VO2peak) with a value of -7.9 ml/Kg/min (95% CI: -9.9, -5.9, p = 0.00001), maximum workload (Wmax) -41.5 (95% CI: -57.9, -25.1 watts, p = 0.00001), ventilatory equivalent (VE/VCO2 ) slope 2.6 (95% CI: 0.3, 4.8), oxygen pulse (O2 pulse)-2.4 ml/beat (95% CI: -3.7, -1.1, p = 0.0003), and maximum heart rate (HRmax) -15 bpm (95% CI: -18, -12 bpm, p = 0.00001), compared with healthy controls. Adolescents (? 12 yrs) with CHD had a greater reduction in VO2peak (-10.0 ml/Kg/min (95% CI: -12.0, -5.3), p < 0.00001), Wmax (-45.5 watts (95% CI: -54.4, -36.7), p < 0.00001) and HRmax (-21 bpm (95% CI: -28, -14), p<0.00001).Suffering CHD in childhood and adolescence is associated with lower exercise capacity as shown by worse VO2peak, Wmax, VE/VCO2 slope, O2 pulse, and HRmax compared with matched healthy controls. The reduction in exercise capacity was greater in adolescents.www.crd.york.ac.uk/prospero/display_record.php?RecordID=208963, identifier: CRD42020208963.Copyright © 2022 Villaseca-Rojas, Varela-Melo, Torres-Castro, Vasconcello-Castillo, Mazzucco, Vilaró and Blanco
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