University of Extremadura

About: University of Extremadura is a education organization based out in Badajoz, Spain. It is known for research contribution in the topics: Population & Hyperspectral imaging. The organization has 7856 authors who have published 18299 publications receiving 396126 citations. The organization is also known as: Universidad de Extremadura.

Catalyzed Pyrolysis of Grape and Olive Bagasse. Influence of Catalyst Type and Chemical Treatment

Abstract: Catalyzed pyrolysis of grape and olive bagasse under different experimental conditions has been studied. Variables investigated were temperature and type and concentration of catalysts. Experiments were carried out in an isothermal manner. Products of pyrolysis are gases (H2, CO, CO2, and CH4), liquids (methanol, acetone, furfurylic alcohol, phenol, furfural, naphthalene, and o-cresol), and solids (chars). Temperature is a significant variable, yielding increases of fixed carbon content, gases, and to a lesser extent, ash percentage. Catalyst presence also yields increases of solid phase content, but the amount of liquid components decrease. Among catalysts applied those of Fe and Zn are the most advisable to obtain gases. Chemical treatment of bagasses with sulfuric or phosphoric acid washing leads to lower char yields, although fixed carbon content is higher and ash presence diminishes with respect to catalyst pyrolysis without chemical pretreatment. A pyrolysis kinetic study based on gas generation fro...

Release of calcium from mitochondrial and nonmitochondrial intracellular stores in mouse pancreatic acinar cells by hydrogen peroxide.

Abstract: In the present study we have studied how [Ca2+] i is influenced by H2O2 in collagenase-dispersed mouse pancreatic acinar cells and the mechanism underlying this effect by using a digital microspectrofluorimetric system. In the presence of normal extracellular calcium concentration, perfusion of pancreatic acinar cells with 1 mm H2O2 caused a slow sustained [Ca2+] i increase, reaching a stable plateau after 10–15 min of perfusion. This increase induced by H2O2 was also observed in a nominally calcium-free medium, reflecting the release of calcium from intracellular store(s). Application of 1 mm H2O2 to acinar cells, in which nonmitochondrial agonist-releasable calcium pools had been previously depleted by a maximal concentration of CCK-8 (1 nm) or thapsigargin (0.5 μm) was still able to induce calcium release. Similar results were observed when thapsigargin was substituted for the mitochondrial uncoupler FCCP (0.5 μm). By contrast, simultaneous addition of thapsigargin and FCCP clearly abolished the H2O2-induced calcium increase. Interestingly, co-incubation of intact pancreatic acinar cells with CCK-8 plus thapsigargin and FCCP in the presence of H2O2 did not significantly affect the transient calcium spike induced by the depletion of nonmitochondrial and mitochondrial agonist-releasable calcium pools, but was followed by a sustained increase of [Ca2+] i . In addition, H2O2 was able to block calcium efflux evoked by CCK and thapsigargin. Finally, the transient increase in [Ca2+] i induced by H2O2 was abolished by an addition of 2 mm dithiothreitol (DTT), a sulfhydryl reducing agent. Our results show that H2O2 releases calcium from CCK-8- and thapsigargin-sensitive intracellular stores and from mitochondria. The action of H2O2 is likely mediated by oxidation of sulfhydryl groups of calcium-ATPases.

Students’ Perceptions and Emotions Toward Learning in a Flipped General Science Classroom

Abstract: Recently, the inverted instruction methodologies are gaining attentions in higher educations by claiming that flipping the classroom engages more effectively students with the learning process. Besides, students’ perceptions and emotions involved in their learning process must be assessed in order to gauge the usability of this relatively new instruction methodology, since it is vital in the educational formation. For this reason, this study intends to evaluate the students’ perceptions and emotions when a flipped classroom setting is used as instruction methodology. This research was conducted in a general science course, sophomore of the Primary Education bachelor degree in the Training Teaching School of the University of Extremadura (Spain). The results show that the students have the overall positive perceptions to a flipped classroom setting. Particularly, over 80 % of them considered that the course was a valuable learning experience. They also found this course more interactive and were willing to have more courses following a flipped model. According to the students’ emotions toward a flipped classroom course, the highest scores were given to the positive emotions, being fun and enthusiasm along with keyword frequency test. Then, the lowest scores were corresponded to negative emotions, being boredom and fear. Therefore, the students attending to a flipped course demonstrated to have more positive and less negative emotions. The results obtained in this study allow drawing a promising tendency about the students’ perceptions and emotions toward the flipped classroom methodology and will contribute to fully frame this relatively new instruction methodology.

Plant Growth Inhibiting Flavonoids in Exudate of Cistus ladanifer and in Associated Soils

Abstract: Of the aglycone flavonoids identified in the exudate of cistus ladanifer, two, the flavone apigenin-4′-(O)-methyl and the flavonol kaempferol-3,7-di(O)-methyl inhibit development of the seedlings of Rumex crispus at 05 and 1 mM Additive effects were observed between the major flavonols of the exudate kaempferol-3-(O)-methyl and kaempferol-3,7-di-(O)-methyl in inhibiting the size of the cotyledons and delaying the germination and cotyledon emergence The presence of apigenin-4′-(O)-methyl, kaempferol3,7-di-(O)-methyl, and kaempferol-3-(O)-methyl was detected in the soils associated with C ladanifer during the summer and autumn months That these compounds are present in the soil and are not restricted to the leaves provides support for the hypothesis that C ladanifer has allelopathic potential

Balneotherapy, Immune System, and Stress Response: A Hormetic Strategy?

Abstract: Balneotherapy is a clinically effective complementary approach in the treatment of low-grade inflammation- and stress-related pathologies. The biological mechanisms by which immersion in mineral-medicinal water and the application of mud alleviate symptoms of several pathologies are still not completely understood, but it is known that neuroendocrine and immunological responses—including both humoral and cell-mediated immunity—to balneotherapy are involved in these mechanisms of effectiveness; leading to anti-inflammatory, analgesic, antioxidant, chondroprotective, and anabolic effects together with neuroendocrine-immune regulation in different conditions. Hormesis can play a critical role in all these biological effects and mechanisms of effectiveness. The hormetic effects of balneotherapy can be related to non-specific factors such as heat—which induces the heat shock response, and therefore the synthesis and release of heat shock proteins—and also to specific biochemical components such as hydrogen sulfide (H2S) in sulfurous water and radon in radioactive water. Results from several investigations suggest that the beneficial effects of balneotherapy and hydrotherapy are consistent with the concept of hormesis, and thus support a role for hormesis in hydrothermal treatments.