74 research outputs found

    Integration of thermoelectric generators (TEG) in solar PVT panels

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    Photovoltaic-thermal hybrid panels (PVT) simultaneously generate electricity and heat with a greater overall efficiency than photovoltaic (PV) and thermal (ST) panels independently. Hybrid PVT-TEG intends to go a step further by integrating thermoelectric modules (TEG) that, based on the Seebeck effect, produce electricity from a temperature difference, thus allowing an additional production of electricity and thus an increase of energy efficiency. In this paper, the design and construction of an experimental installation, consisting of two solar collectors PVT, one of them with 19 TEG modules integrated is presented. This prototype will allow to observe the increase in the electrical production that can be obtained by introducing TEG in PVT modules and the differences in the behaviour (yields and W/Q ratio) between modules with and without TEG

    Design of a sun tracker for the automatic measurement of spectral irradiance and construction of an irradiance database in the 330-1100 nm range

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    An automatic global and direct solar spectral irradiance system has been designed based on two LICOR spectroradiometers equipped with fibre optics and remote cosine sensors. To measure direct irradiance a sun tracker based on step motors has been developed. The whole system is autonomous and works continuously. From the measurements provided by this system a spectral irradiance database in the 330-1100 nm range has been created. This database contains normal direct and global horizontal irradiances as well as diffuse irradiance on a horizontal plane, together with total atmospheric optical thickness and aerosol optical depth

    Intercomparison of spectroradiometers and Sun photometers for the determination of the aerosol optical depth during the VELETA-2002 field campaign

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    [ 1] In July 2002 the VELETA-2002 field campaign was held in Sierra Nevada ( Granada) in the south of Spain. The main objectives of this field campaign were the study of the influence of elevation and atmospheric aerosols on measured UV radiation. In the first stage of the field campaign, a common calibration and intercomparison between Licor-1800 spectroradiometers and Cimel-318 Sun photometers was performed in order to assess the quality of the measurements from the whole campaign. The intercomparison of the Licor spectroradiometers showed, for both direct and global irradiances, that when the comparisons were restricted to the visible part of the spectrum the deviations were within the instruments' nominal accuracies which allows us to rely on these instruments for measuring physical properties of aerosols at the different measurement stations. A simultaneous calibration on AOD data was performed for the Cimel-318 Sun photometers. When a common calibration and methodology was applied, the deviation was lowered to much less than 0.01 for AOD. At the same time an intercomparison has been made between the AOD values given by the spectroradiometers and the Sun photometers, with deviations obtained from 0.01 to 0.03 for the AOD in the visible range, depending on the channel. In the UVA range, the AOD uncertainty was estimated to be around 0.02 and 0.05 for Cimel and Licor respectively. In general the experimental differences were in agreement with this uncertainty estimation. In the UVB range the AOD measurements should not be used due to maximum instrumental uncertainties

    A glucotolerant β-glucosidase from the fungus Talaromyces amestolkiae and its conversion into a glycosynthase for glycosylation of phenolic compounds

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    The interest for finding novel β-glucosidases that can improve the yields to produce second-generation (2G) biofuels is still very high. One of the most desired features for these enzymes is glucose tolerance, which enables their optimal activity under high-glucose concentrations. Besides, there is an additional focus of attention on finding novel enzymatic alternatives for glycoside synthesis, for which a mutated version of glycosidases, named glycosynthases, has gained much interest in recent years. Results In this work, a glucotolerant β-glucosidase (BGL-1) from the ascomycete fungus Talaromyces amestolkiae has been heterologously expressed in Pichia pastoris, purified, and characterized. The enzyme showed good efficiency on p-nitrophenyl glucopyranoside (pNPG) (Km= 3.36 ± 0.7 mM, kcat= 898.31 s−1), but its activity on cellooligosaccharides, the natural substrates of these enzymes, was much lower, which could limit its exploitation in lignocellulose degradation applications. Interestingly, when examining the substrate specificity of BGL-1, it showed to be more active on sophorose, the β-1,2 disaccharide of glucose, than on cellobiose. Besides, the transglycosylation profile of BGL-1 was examined, and, for expanding its synthetic capacities, it was converted into a glycosynthase. The mutant enzyme, named BGL-1-E521G, was able to use α-d-glucosyl-fluoride as donor in glycosylation reactions, and synthesized glucosylated derivatives of different pNP-sugars in a regioselective manner, as well as of some phenolic compounds of industrial interest, such as epigallocatechin gallate (EGCG). Conclusions In this work, we report the characterization of a novel glucotolerant 1,2-β-glucosidase, which also has a considerable activity on 1,4-β-glucosyl bonds, that has been cloned in P. pastoris, produced, purified and characterized. In addition, the enzyme was converted into an efficient glycosynthase, able to transfer glucose molecules to a diversity of acceptors for obtaining compounds of interest. The remarkable capacities of BGL-1 and its glycosynthase mutant, both in hydrolysis and synthesis, suggest that it could be an interesting tool for biotechnological applications

    Intrinsic excitation-inhibition imbalance affects medial prefrontal cortex differently in autistic men versus women

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    Excitation-inhibition (E:I) imbalance is theorized as an important pathophysiological mechanism in autism. Autism affects males more frequently than females and sex-related mechanisms (e.g., X-linked genes, androgen hormones) can influence E:I balance. This suggests that E:I imbalance may affect autism differently in males versus females. With a combination of in-silico modeling and in-vivo chemogenetic manipulations in mice, we first show that a time-series metric estimated from fMRI BOLD signal, the Hurst exponent (H), can be an index for underlying change in the synaptic E:I ratio. In autism we find that H is reduced, indicating increased excitation, in the medial prefrontal cortex (MPFC) of autistic males but not females. Increasingly intact MPFC H is also associated with heightened ability to behaviorally camouflage social-communicative difficulties, but only in autistic females. This work suggests that H in BOLD can index synaptic E:I ratio and that E:I imbalance affects autistic males and females differently

    Las emociones en la enseñanza de las ciencias

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    En la primera parte del artículo, se incide en la importancia del estudio de las emociones desde la didáctica de las ciencias, así como en la necesidad de establecer programas de intervención metacognitivos y metaemocionales, tanto en el aprendizaje como en la formación del profesorado, para que alumnos y profesores puedan conocer sus emociones, controlarlas y autorregularlas. En la segunda parte, nos centramos en las emociones en el conocimiento didáctico del contenido del profesorado de ciencias, incluyendo algunos resultados tanto del diagnóstico emocional del profesorado, según distintas variables, como del programa de intervención de la Universidad de Extremadura.The first part of this communication highlights the importance of studying emotions in the context of science teaching. It also examines the need for programs of meta-emotional and metacognitive intervention in learning and teacher education that are aimed at both the future teachers'and their pupils' gaining awareness of, and then controlling and self-regulating, their emotions. The second part focuses on the role emotions play in science teachers' pædagogical content knowledge, with the presentation of some results concerning the University of Extremadura's intervention program and the emotional diagnosis of teachers.En la primera part de l'article, s'incideix en la importància de l'estudi de les emocions des de la didàctica de les ciències, així com en la necessitat d'establir programes d'intervenció metacognitivos i metaemocionales, tant en l'aprenentatge com en la formació del professorat, perquè alumnes i professors puguin conèixer les seves emocions, controlar-les i autorregularlas. En la segona part, ens centrem en les emocions en el coneixement didàctic del contingut del professorat de ciències, incloent alguns resultats tant del diagnòstic emocional del professorat, segons diferents variables, com del programa d'intervenció de la Universitat d'Extremadura

    A Fungal Versatile GH10 Endoxylanase and Its Glycosynthase Variant: Synthesis of Xylooligosaccharides and Glycosides of Bioactive Phenolic Compounds

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    The study of endoxylanases as catalysts to valorize hemicellulosic residues and to obtain glycosides with improved properties is a topic of great industrial interest. In this work, a GH10 β-1,4-endoxylanase (XynSOS), from the ascomycetous fungus Talaromyces amestolkiae, has been het- erologously produced in Pichia pastoris, purified, and characterized. rXynSOS is a highly glycosylated monomeric enzyme of 53 kDa that contains a functional CBM1 domain and shows its optimal activity on azurine cross-linked (AZCL)–beechwood xylan at 70 ◦C and pH 5. Substrate specificity and kinetic studies confirmed its versatility and high affinity for beechwood xylan and wheat arabi- noxylan. Moreover, rXynSOS was capable of transglycosylating phenolic compounds, although with low efficiencies. For expanding its synthetic capacity, a glycosynthase variant of rXynSOS was developed by directed mutagenesis, replacing its nucleophile catalytic residue E236 by a glycine (rXynSOS-E236G). This novel glycosynthase was able to synthesize β-1,4-xylooligosaccharides (XOS) of different lengths (four, six, eight, and ten xylose units), which are known to be emerging prebiotics. rXynSOS-E236G was also much more active than the native enzyme in the glycosylation of a broad range of phenolic compounds with antioxidant properties. The interesting capabilities of rXynSOS and its glycosynthase variant make them promising tools for biotechnological application.This research was funded by the MICIU/AEI/FEDER [RTI2018-093683-B-I00, RTI2018- 094751-B-C22, PID2019-107476GB-I00], Comunidad de Madrid [RETOPROSOST-2-CM P2018/EMT- 4459], and CIBERES (an initiative from the Spanish Institute of Health Carlos IPeer reviewe

    Phase III Trial of Adjuvant Capecitabine After Standard Neo-/Adjuvant Chemotherapy in Patients With Early Triple-Negative Breast Cancer (GEICAM/2003-11_CIBOMA/2004-01)

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    Altres ajuts: Agustí Barnadas: Honoraria: Pfizer. Consulting or Advisory Role: Pfizer, Novartis, Eli Lilly. Speakers'Bureau: Roche, Pfizer, Novartis, Genomic Health International. Travel, Accommodations, Expenses: Roche, Pfizer; Miguel A. Seguí: Consulting or Advisory Role: Roche, Pfizer, Novartis, Amgen, Eisai, Eli Lilly. Speakers' Bureau: Roche, Pfizer, Amgen. Research Funding: Roche (Inst), Novartis (Inst). Travel, Accommodations, Expenses: Roche, Pfizer, Novartis, Amgen.Operable triple-negative breast cancers (TNBCs) have a higher risk of relapse than non-TNBCs with standard therapy. The GEICAM/2003-11_CIBOMA/2004-01 trial explored extended adjuvant capecitabine after completion of standard chemotherapy in patients with early TNBC. Eligible patients were those with operable, node-positive-or node negative with tumor 1 cm or greater-TNBC, with prior anthracycline- and/or taxane-containing chemotherapy. After central confirmation of TNBC status by immunohistochemistry, patients were randomly assigned to either capecitabine or observation. Stratification factors included institution, prior taxane-based therapy, involved axillary lymph nodes, and centrally determined phenotype (basal v nonbasal, according to cytokeratins 5/6 and/or epidermal growth factor receptor positivity by immunohistochemistry). The primary objective was to compare disease-free survival (DFS) between both arms. Eight hundred seventy-six patients were randomly assigned to capecitabine (n = 448) or observation (n = 428). Median age was 49 years, 55.9% were lymph node negative, 73.9% had a basal phenotype, and 67.5% received previous anthracyclines plus taxanes. Median length of follow-up was 7.3 years. DFS was not significantly prolonged with capecitabine versus observation [hazard ratio (HR), 0.82; 95% CI, 0.63 to 1.06; P =.136]. In a preplanned subgroup analysis, nonbasal patients seemed to derive benefit from the addition of capecitabine with a DFS HR of 0.53 versus 0.94 in those with basal phenotype (interaction test P =.0694) and an HR for overall survival of 0.42 versus 1.23 in basal phenotype (interaction test P =.0052). Tolerance of capecitabine was as expected, with 75.2% of patients completing the planned 8 cycles. This study failed to show a statistically significant increase in DFS by adding extended capecitabine to standard chemotherapy in patients with early TNBC. In a preplanned subset analysis, patients with nonbasal phenotype seemed to obtain benefit with capecitabine, although this will require additional validation
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