2.1 Estudios de doctorado y postdoctorado
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PublicationThe spinning voltage influence on the growth of zno-rgo nanorods for photocatalytic degradation of methyl orange dye(MDPI AG, 2020)In this work, well-designed zinc oxide-reduced graphene oxide (ZnO-rGO) nanorods (NRs) were synthesized by a hydrothermal method using electrospun ZnO-rGO seed layers. The ZnO-rGO seed layers were fabricated on fluorine-doped tin oxide (FTO) glass substrates through calcined of electrospun nanofibers at 400◦C in the air for 1 h. The nanofibers were prepared by electrospinning different spinning voltages and a spinning solution containing zinc acetate, polyvinyl pyrrolidone, and 0.2 wt% rGO. From a detailed characterization using various analytical techniques, for instance, X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), Raman spectroscopy, photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS), the dependence of the structure, morphology, and optical properties of the ZnO-rGO NRs was demonstrated. The photocatalytic activities of ZnO-rGO nanorods were evaluated through the degradation of dye methyl orange (MO). The results show that the change of spinning voltages and the coupling of rGO with ZnO improved photodecomposition efficiency as compared to pure ZnO. The highest photocatalytic efficiency was obtained for the ZnO-rGO NRs prepared with a spinning voltage of 40 kV. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
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PublicationChitosan active films containing agro-industrial residue extracts for shelf life extension of chicken restructured product(Elsevier Ltd, 2018)This study aimed to develop chitosan films incorporating natural antioxidants from peanut skin (EPS) and pink pepper residue (EPP) extracts, as well as to evaluate their effects on lipid oxidation, pH, color, and microbial counts of a restructured chicken product. EPS had higher phenolic content and antioxidant activity compared to EPP. When both extracts were applied to chicken meat and the chitosan films, there were no differences for color, pH and total mesophilic counts compared to control at the end of the storage period. For lipid oxidation (peroxide value and thiobarbituric acid reactive substances), both extracts proved to be as effective as butylated hydroxytoluene to maintain the oxidative stability of the chicken product. The microbial counts of psychrotrophic microorganisms were significantly lower for treatments with active films. Chitosan active films with residue extracts may maintain the quality of chicken products due to their antioxidant and antimicrobial potential.
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PublicationInsulin-like growth factor I modulates sleep through hypothalamic orexin neurons(John Wiley and Sons Inc, 2020)Although sleep disturbances are common co-morbidities of metabolic diseases, the underlying processes linking both are not yet fully defined. Changes in the duration of sleep are paralleled by changes in the levels of insulin-like growth factor-I (IGF-I), an anabolic hormone that shows a circadian pattern in the circulation and activity-dependent entrance in the brain. However, the specific role, if any, of IGF-I in this universal homeostatic process remains poorly understood. We now report that the activity of orexin neurons, a discrete cell population in the lateral hypothalamus that is involved in the circadian sleep/wake cycle and arousal, is modulated by IGF-I. Furthermore, mice with blunted IGF-I receptor activity in orexin neurons have lower levels of orexin in the hypothalamus, show altered electro-corticographic patterns with predominant slow wave activity, and reduced onset-sleep latency. Collectively, these results extend the role in the brain of this pleiotropic growth factor to shaping sleep architecture through the regulation of orexin neurons. We speculate that poor sleep quality associated to diverse conditions may be related to disturbed brain IGF-I input to orexin neurons. © 2020 Federation of American Societies for Experimental Biology
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PublicationEvaluating the Guo–Campanella viscoelastic model(Blackwell Publishing Ltd, 2018)Biological materials are characterized by complex structures and compositions, leading to viscoelastic behavior. Their viscoelastic characterization is important for the evaluation, design, and optimization of processes to ensure high quality products. Proposals of methodologies of analysis and modeling are critical steps in studying the rheological properties of these materials. In this context, a new model, the Guo-Campanella Model, was recently proposed to describe the stress-relaxation behavior of biological material. This work is an independent and impartial evaluation of this new model. It considers 10 different samples, comprising in natura and processed foods, from both plant and animal bases. For comparison, a Generalized Maxwell Model and the Peleg Model were also evaluated. The Guo-Campanella Model fitted the stress-relaxation data of evaluated products well, demonstrating its validity for describing the viscoelastic behavior of biological materials with different structures, sources, and processing. Finally, the Guo-Campanella Model parameters were evaluated and their interpretations and possible uses described. It was shown that the Guo-Campanella Model can be successfully used for future studies.
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PublicationEffects of long-term antipsychotics treatment on body weight: A population-based cohort study(SAGE Publications Ltd, 2020)Background: Antipsychotics are often prescribed for long-term periods, however, most evidence of their impact on body weight comes from short-term clinical trials. Particularly, impact associated with dosage has been barely studied. Aims: The aim of this study was to describe the short- and long-term change in body weight of people initiated on high or low doses of the three most commonly prescribed second-generation antipsychotics. Methods: Retrospective cohorts of individuals with a diagnosed psychotic disorder observed from 2005 to 2015 in the UK primary care. The exposure was the first prescription of olanzapine, quetiapine or risperidone. The main outcome was change in body weight four years before and four years after initiation of antipsychotic treatment, stratified on sex and ‘low’ or ‘high’ dose. Results: In total, 22,306 women and 16,559 men were observed. Olanzapine treatment was associated with the highest change in weight, with higher doses resulting in more weight gain. After 4 years, given a high dose of olanzapine (> 5 mg), women gained on average +6.1 kg; whereas given a low dose (⩽ 5 mg), they gained +4.4 kg. During the first six weeks of olanzapine treatment, they gained on average +3.2 kg on high dose and +1.9 kg on low dose. The trends were similar for men. Individuals prescribed risperidone and quetiapine experienced less weight gain in both the short- and long-term. Conclusions: Olanzapine treatment was associated with the highest increase in weight. Higher doses were associated with more weight gain. Doctors should prescribe the lowest effective dose to balance mental-health benefits, weight gain and other adverse effects. © The Author(s) 2019.