78 research outputs found

    A virtual laboratory for an enhanced and safe understanding of the electric transformers operation

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    [EN] The paper presents an educational software designed to simulate the behaviour of an electric transformer under no-load, shortcircuit and load test, measuring its input and output magnitudes through network analysers, and enabling the supply voltage and load regulations. This virtual laboratory allows to achieve several objectives. First, the student becomes familiar with the system to be operated in the real laboratory, reducing the subsequent electrical risk and optimizing the time required for carrying out the practice. Second, it enhances the understanding of transformers behaviour, its modelling through the equivalent electrical circuit, and the calculation of its two most characteristic parameters during its operation (performance and internal voltage drop). Finally, the application auto evaluates the transformer characterization performed by the student. The simulator reproduces schematically, but precisely, the assembly that the student faces during the lab lesson: an autotransformer to regulate the supply voltage, a transformer, two input and output network analysers, and different types of loads. The tool is structured in three panels. In the first panel, the student selects a transformer from 24 options, and performs its shortcircuit and no-load tests to characterize it through its electric equivalent circuit. Panels 2 and 3 enable load tests and its main characteristics calculation (performance and internal voltage drop). The student results are introduced in the app to perform auto-evaluation. To measure the performance and usefulness of the application, it has been implemented in the lab lessons of the subject ¿Electrical Technology¿, belonging to the Bachelor¿s Degree in Industrial Electronics and Automation Engineering, taught at the Polytechnic University of Valencia (Spain). The sample size is 96 students and the methodology used is as follows. The 96 students are subdivided into four groups. The practice lessons follow this sequence: a refreshment of the transformer concepts needed + explanation of the practice lesson to be performed + explanation and use of the app solving an example (only for groups 1 and 2) + real laboratory experience + final test on transformers. Finally, the performances between groups 1-2 and 3-4 are compared. It is observed that the students of groups 1 and 2 obtain better results in the final tests than those of groups 3 and 4, reaching higher levels of learning thanks to the previous use of the simulator. On the other hand, it is also observed that the time of completion of the real laboratory practice decreases substantially in groups 1 and 2. As a conclusion, there is a great benefit in using this application specifically designed to obtain very specific learning results, since the application is fully adapted to the needs of the degree and therefore to the level of knowledge that the students need to acquire according to the perception and experience of the teaching staff. Finally, based on the results, the application is permanently implemented in the laboratory lessons of Electrical Technology.This project is supported by Universitat Politècnica de València through the Project of Innovation and Educational Improvement Program (PIME 2018-2019/B26).Bonet-Jara, J.; Pons Llinares, J.; Bernal-Perez, S.; Sabater I Serra, R. (2019). A virtual laboratory for an enhanced and safe understanding of the electric transformers operation. IATED. 9177-9186. https://doi.org/10.21125/inted.2019.2277S9177918

    Essential Oils of <em>Thymbra capitata</em> and <em>Thymus hyemalis</em> and Their Uses Based on Their Bioactivity

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    Essential oils (EO) are volatile compounds produced by the secondary metabolism of aromatic plants. They are complex mixtures whose main components are synthesized by the mevalonic acid and the methyl erythritol phosphate pathways, which lead to the biosynthesis of terpenes, and the shikimic acid pathway, responsible for the biosynthesis of phenylpropanoid compounds. In nature, EOs are stored in the aerial parts of the plant, being of vital importance for their survival due to their antimicrobial properties. In addition, EOs provide protection against herbivores to the aromatic plants and allow them to repel or attract insects because of their strong fragrance, as well as compete with other plants of the same environment. Humans have exploited the properties of their EOs since ancient times, being used as medicinal remedies, among other uses. Currently, aromatic plants are used in pharmaceutical and food industries. One of the most commonly used aromatic plants is thyme. Thyme is a perennial aromatic plant, taxonomically belonging to the genera Thymus and Thymbra, belonging to the family Lamiaceae. These plants are very abundant in the Mediterranean Region. In this review, we focus on the study of the properties and use of EOs of Thymbra capitata (L) Cav. and Thymus hyemalis Lange., whose EOs are rich in phenolic monoterpenes. These compounds are responsible for their antioxidant, anti-inflammatory, anticarcinogenic, antibacterial, antifungal, and antiparasitic properties

    Revalorization of Broccoli By-Products for Cosmetic Uses Using Supercritical Fluid Extraction

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    The agri-food industry is currently one of themain engines of economic developmentworldwide. The region ofMurcia is a reference area in Europe for the cultivation of fruits and vegetables and produces the bulk of Spanish exports of broccoli (Brassica oleracea var. italica). The processing of fresh produce generates a huge number of by-products that represent an important economic and environmental problem when discarded. In this work, an advanced extraction technique using environmentally friendly solvents was applied to assess the revalorization of broccoli by-products, by performing a comparative analysis with conventional extraction. To achieve this goal, supercritical fluid extraction based on response surface methodology was performed using CO2 and ethanol as solvents. The results obtained showed that the supercritical fluid extracts were rich in -carotene, phenolic compounds, chlorophylls and phytosterols. Moreover, in bioactivity assays, the supercritical fluid extracts exhibited a high antioxidant activity and a cytoprotective effect in a non-tumorigenic keratinocyte cell line exposed to ultraviolet B light. The results indicate that supercritical fluid extracts from broccoli by-products could potentially serve as an ingredient for cosmetic purposes

    Development of an e-learning platform for improving and assessing the student outcomes in electrical engineering

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    [EN] In the European Higher Education Area, the concept of `education¿ can be defined as a process that facilitates learning. The process will culminate successfully if our students have really learned and not necessarily because we have taught them. Taking into account the educational environment in which we are immersed, the learning process must be turned into a process where the students become aware of their goals and the teacher is transformed into a guide that escorts the students towards the achievement of the objectives. The organization of teaching in this environment involves developing new conceptualizations and methodologies, which can be applied jointly to classical methodologies, acting in a complementary and also synergistic manner. Currently, all academic institutions use virtual campus platforms for educational purposes. At the Universitat Politècnica de València (Spain), this virtual system can be used as a repository of academic material but also has tools for the development of applications based on e-learning. In the present paper, an e-learning platform has been designed for students of electronic engineering that guide the learners to understand theoretical concepts, integrate theory and practice, and apply knowledge and skills to develop a viable solution to specific problems. The importance of defining and assessing learning outcomes, that is, the competences that students should have acquired and can use, have also been considered. To achieve this goal, a problem-based learning approach has been used so the students learn to identify and interpret data and design strategies to solve problems applying concepts of analysis of electrical circuits. First, the most relevant competences that the students must achieve has been analysed (`Knowledge and use of the principles of theory of circuits and electric machines¿, `Applied knowledge of electrical engineering¿ and `Analysis and resolution of problems¿). Based on them, a battery of tests and tasks has been designed, in order to reinforce the theoretic concepts and analyse and solve problems. The `Test & Quizzes¿ tool of the system has been used to develop the e-learning platform, in which selfevaluation has been also integrated in order to become an effective instrument for learning. The focus has been put on the design of the strategy in relation to the competences that students should acquire, the experience gained during the development of the e-learning platform and the students¿ satisfaction after the implementation.This project is supported by Universitat Politècnica de València through the Project of Innovation and Educational Improvement Program (PIME 2018-2019/B26).Pons Llinares, J.; Bernal-Perez, S.; García-Sánchez, TM.; Bonet-Jara, J.; Sabater I Serra, R. (2019). Development of an e-learning platform for improving and assessing the student outcomes in electrical engineering. IATED. 9169-9176. https://doi.org/10.21125/inted.2019.2276S9169917

    Análisis del espacio de trabajo de un robot paralelo de 3RRR

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    Comunicación presentada en las XXIX Jornadas de Automática, Tarragona, 3-5 Septiembre 2008.El objetivo de este artículo es realizar el análisis del espacio de trabajo de un robot paralelo esférico del tipo 3RRR mediante una herramienta matemática desarrollada en Matlab. Este 3RRR contiene una particularidad que lo diferencia con respecto a los robots esféricos comunes debido a las exigencias de su aplicación: su centro de rotación no se encuentra en el centro del robot. Basándonos en un parámetro que define la habilidad o destreza del robot (dexterity), calcularemos el valor de las variables que optimizan su espacio de trabajo

    A Multitrait Genetic Study of Hemostatic Factors and Hemorrhagic Transformation after Stroke Treatment

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    BACKGROUND: Thrombolytic recombinant tissue plasminogen activator (r-tPA) treatment is the only pharmacologic intervention available in the ischemic stroke acute phase. This treatment is associated with an increased risk of intracerebral hemorrhages, known as hemorrhagic transformations (HTs), which worsen the patient\u27s prognosis. OBJECTIVES: to investigate the association between genetically determined natural hemostatic factors\u27 levels and increased risk of HT after r-tPA treatment. METHODS: Using data from genome-wide association studies on the risk of HT after r-tPA treatment and data on 7 hemostatic factors (factor [F]VII, FVIII, von Willebrand factor [VWF], FXI, fibrinogen, plasminogen activator inhibitor-1, and tissue plasminogen activator), we performed local and global genetic correlation estimation multitrait analyses and colocalization and 2-sample Mendelian randomization analyses between hemostatic factors and HT. RESULTS: Local correlations identified a genomic region on chromosome 16 with shared covariance: fibrinogen-HT, P = 2.45 × 10 CONCLUSION: We identified 4 shared loci between hemostatic factors and HT after r-tPA treatment, suggesting common regulatory mechanisms between fibrinogen and VWF levels and HT. Further research to determine a possible mediating effect of fibrinogen on HT risk is needed

    Methyl jasmonate enhanced production of rosmarinic acid in cell cultures of Satureja khuzistanica in a bioreactor

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    The growing interest in rosmarinic acid (RA), an ester of caffeic acid and 3,4‐dihydroxyphenyl lactic acid, is due to its biological activities, which include cognitive‐enhancing effects, slowing the development of Alzheimer's disease, cancer chemoprotection, and anti‐inflammatory activity. Inspired by the challenge of meeting the growing demand for this plant secondary metabolite, we developed a biotechnological platform based on cell suspension cultures of Satureja khuzistanica. The high amounts of RA produced by this system accumulated mainly inside the cells. To further improve production, two elicitors, 100 μM methyl jasmonate (MeJA) and 40 mM cyclodextrin (CD), were tested, separately and together. MeJA increased RA productivity more than 3‐fold, the elicited cultures achieving an RA production of 3.9 g L−1 without affecting biomass productivity. CD did not have a clear effect on RA production, and under the combined treatment of MeJA + CD only a small amount of RA was released to the medium. When the cell culture was transferred from a shake flask to a wave‐mixed bioreactor, a maximum RA production of 3.1 g L−1 and biomass productivity of 18.7 g L−1 d−1 was achieved under MeJA elicitation, demonstrating the suitability of S. khuzistanica cell suspensions for the biotechnological production of this bioactive plant secondary metabolite

    A multitrait genetic study of hemostatic factors and hemorrhagic transformation after stroke treatment

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    [Background] Thrombolytic recombinant tissue plasminogen activator (r-tPA) treatment is the only pharmacologic intervention available in the ischemic stroke acute phase. This treatment is associated with an increased risk of intracerebral hemorrhages, known as hemorrhagic transformations (HTs), which worsen the patient’s prognosis.[Objectives] To investigate the association between genetically determined natural hemostatic factors’ levels and increased risk of HT after r-tPA treatment.[Methods] Using data from genome-wide association studies on the risk of HT after r-tPA treatment and data on 7 hemostatic factors (factor [F]VII, FVIII, von Willebrand factor [VWF], FXI, fibrinogen, plasminogen activator inhibitor-1, and tissue plasminogen activator), we performed local and global genetic correlation estimation multitrait analyses and colocalization and 2-sample Mendelian randomization analyses between hemostatic factors and HT.[Results] Local correlations identified a genomic region on chromosome 16 with shared covariance: fibrinogen-HT, P = 2.45 × 10−11. Multitrait analysis between fibrinogen-HT revealed 3 loci that simultaneously regulate circulating levels of fibrinogen and risk of HT: rs56026866 (PLXND1), P = 8.80 × 10−10; rs1421067 (CHD9), P = 1.81 × 10−14; and rs34780449, near ROBO1 gene, P = 1.64 × 10−8. Multitrait analysis between VWF-HT showed a novel common association regulating VWF and risk of HT after r-tPA at rs10942300 (ZNF366), P = 1.81 × 10−14. Mendelian randomization analysis did not find significant causal associations, although a nominal association was observed for FXI-HT (inverse-variance weighted estimate [SE], 0.07 [−0.29 to 0.00]; odds ratio, 0.87; 95% CI, 0.75-1.00; raw P = .05).[Conclusion] We identified 4 shared loci between hemostatic factors and HT after r-tPA treatment, suggesting common regulatory mechanisms between fibrinogen and VWF levels and HT. Further research to determine a possible mediating effect of fibrinogen on HT risk is needed.This study is supported in part by the National Heart, Lung, and Blood Institute grants HL134894, HL139553, and HL141291. G.T.-S. is supported by the Pla Estratègic de Recerca i Innovació en Salut grant from the Catalan Department of Health for junior research personnel (SLT017/20/000100). M.S.-L. is supported by a Miguel Servet contract from the Instituto de Salud Carlos III (ISCIII) Spanish Health Institute (CPII22/00007) and cofinanced by the European Social Fund. E.M. is supported by a Río Hortega Contract (CM18/00198) from the ISCIII. J.C.-M. is supported by an Agència de Gestió d’Ajuts Universitaris i de Recerca Contract (FI_DGR 2020, grant number 2020FI_B1 00157) cofinanced by the European Social Fund. C.G.-F. is supported by a Sara Borrell Contract (CD20/00043) from ISCIII and Fondo Europeo de Desarrollo Regional (ISCIII- FEDER). M.L. is supported by a Contratos Predoctorales de Formación en Investigación en Salud Contract from the ISCIII (FI19/00309).Peer reviewe
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