115 research outputs found
Convergent Total Synthesis of the Siderophore Piscibactin as Its Ga3+ Complex
Author accepted manuscript[Abstract] The siderophore piscibactin is a key virulence factor involved in the iron uptake of pathogenic bacteria Photobacterium damselae subsp. piscicida and Vibrio anguillarum, responsible for the fish diseases photobacterioisis (pasteurellosis) and vibriosis, respectively. A convergent total synthesis of its Ga3+ complex using l-/d-cysteine as chiral agents and Meldrum’s acid is described. A Staudinger reduction/Aza-Wittig process in the synthesis of the acid-sensitive β-hydroxy-2,4-disubstituted thiazoline moiety and the convenient protecting groups was a key step in this synthesis.This work was supported by grants RTI2018-093634-B-C22 (AEI/FEDER, EU) from the State Agency for Research (AEI) of Spain, cofunded by the FEDER Programme from the European Union, GRC2018/039 and ED431E 2018/03 of CICA-INIBIC strategic group from Xunta de Galicia, and BLUEBIOLAB (0474_BLUEBIOLAB_1_E), Programme INTERREG V A of Spain-Portugal (POCTEP). We also are thankful for one of the referee’s comments about the possible applications of the deuterated form of Pcb that were enclosed in the manuscriptXunta de Galicia; GRC2018/039Xunta de Galicia; ED431E 2018/0
Beneficios de la gamificación en el aula de música de Educación Secundaria.
Partiendo de una propuesta didáctica gamificada, este artículo pretende mostrar la relación
existente entre el uso de la gamificación, la consecución de los objetivos didácticos y el nivel de
satisfacción del alumnado que cursa Educación Secundaria Obligatoria. Se ha diseñado una
Unidad Didáctica para ser implementada a través de gamificación a un grupo experimental y
mediante una metodología de corte tradicional a un grupo control. La metodología ha sido
cuantitativa y descriptiva, utilizando dos instrumentos diferentes para la recogida de datos y su
posterior análisis. Se ha observado el comportamiento del rendimiento y la satisfacción en el
proceso de enseñanza-aprendizaje del alumnado, en función de la metodología didáctica
empleada. Asimismo, se han comparado los resultados de aprendizaje obtenidos en ambas. Se
puede avanzar que los resultados han sido mejores tanto a nivel de rendimiento como de
satisfacción del alumnado, en el grupo que ha trabajado a través de gamificació
Beneficios de la gamificación en el aula de música de Educación Secundaria.
Partiendo de una propuesta didáctica gamificada, este artículo pretende mostrar la relación
existente entre el uso de la gamificación, la consecución de los objetivos didácticos y el nivel de
satisfacción del alumnado que cursa Educación Secundaria Obligatoria. Se ha diseñado una
Unidad Didáctica para ser implementada a través de gamificación a un grupo experimental y
mediante una metodología de corte tradicional a un grupo control. La metodología ha sido
cuantitativa y descriptiva, utilizando dos instrumentos diferentes para la recogida de datos y su
posterior análisis. Se ha observado el comportamiento del rendimiento y la satisfacción en el
proceso de enseñanza-aprendizaje del alumnado, en función de la metodología didáctica
empleada. Asimismo, se han comparado los resultados de aprendizaje obtenidos en ambas. Se
puede avanzar que los resultados han sido mejores tanto a nivel de rendimiento como de
satisfacción del alumnado, en el grupo que ha trabajado a través de gamificació
Deseño e desenvolvemento e avaliación de talleres sobre o coñecemento e o manexo de materiais manipulativos para traballar contidos en estatística para nenos e nenas de Educación Primaria
Banco de experiencias de Aprendizaxe Servizo. Convocatoria 2016/201
Deseño e desenvolvemento e avaliación de talleres sobre o coñecemento e o manexo de materiais manipulativos para traballar contidos en estatística para nenos e nenas de Educación Primaria
Banco de experiencias de Aprendizaxe Servizo. Convocatoria 2016/201
On the physical properties of mixtures of nitrate salts and protic ionic liquids
We report a systematic study of the effect of salt concentration and its cation valence on several equilibrium and transport properties of mixtures of the model protic ionic liquid ethylammonium nitrate with monovalent (LiNO3), divalent (Mg(NO3)2 and Ca(NO3)2), and trivalent (Al(NO3)3) salts. These properties, determined by appropriate experimental techniques, include density, sound velocity, refractive index, surface tension, conductivity and viscosity. Single-particle dynamics and radial distribution functions were also analyzed by means of molecular dynamics simulations. The temperature dependence of the conductivity was studied in the Vogel-Fulcher-Tammann framework, and we obtained effective activation energies, fragility indexes, and Vogel temperatures. In addition, we performed a high-temperature Arrhenius analysis and we calculated the activation energies of both conductivity and viscosity. Finally, the exponents of the fractional Walden rule for the different mixtures were obtained and the ionicities and fragilities of the systems were analyzed, proving that all the mixtures are subionic and fragile. The distortion of the network of hydrogen bonds characteristic of protic ionic liquids and the formation of long-lived anionic aggregates composed of the cations of the added salt and the nitrate anions in their first solvation shell were found to have a deep impact on the analyzed properties. The role of the surface charge density of the salt cations on the structure and transport properties of the solutions is detailedly analyzed and related to solvation of salt species in the polar nanoregions of the ionic liquid (nanostructured solvation)The financial support of the Spanish Ministry of Economy and Competitiveness (Projects MAT2017-89239-C2-1-P and MAT2017-89239- C2-2-P) is gratefully acknowledged. Moreover, this work was funded by the Xunta de Galicia (ED431D 2017/06, ED431E 2018/08, GRC ED431C 2016/001 and GRC ED431C 2020/10). All these research projects were partially supported by FEDER. P. V. thanks the Spanish Ministry of Science, Innovation and Universities for his FPI grant (PRE2018-084212). T.M.-M. thanks the Spanish Ministry of Science, Innovation and Universities for her Juan de la Cierva grant (IJC2018-036774-I).J. J. Parajó thanks the funding support of I2C postdoctoral program of Xunta de Galicia. Y. A. thanks the funding support from postdoctoral Program of Xunta de Galicia (ED481B-2021-027)S
Synthesis, microstructure and volumetry of novel metal thiocyanate ionic liquids with [BMIM] cation
We present a new family of ionic liquids (ILs) with a common cation, 1-butyl-3-methyl imidazolium, the popular [BMIM]+ (also written C4C1Im+) and a variety of anionic complexes (also called adducts) based in thiocyanate (SCN)?: one blank compound, BMIM(SCN), and ten doped with metals having different oxidation states: Al+3, Mn+2, Fe+3, Cr+3, Ni+2, Hg+2, Zn+2, Co+2, Cd+2 and Cu+, forming, respectively, [BMIM]3[Al(SCN)6], [BMIM]4 Mn(SCN)6, [BMIM]3 Fe(SCN)6, [BMIM]3 Cr(SCN)6, [BMIM]4 Ni(SCN)6, [BMIM]2 Hg(SCN)4, [BMIM]2 Zn(SCN)4, [BMIM]2 Co(SCN)4, [BMIM]2 Cd(SCN)4 and [BMIM]3 Cu(SCN)4. All of them were synthesized by us, except the blank IL and the Co thiocyanate, which are commercial. Obtained products have been characterized by NMR, and also by electrospray ionization, MS-ES, which allows the determination of the new ILs purities. Then, compounds have been analyzed using FT-IR and Raman spectroscopy. In addition, magnetic susceptibility and refractive index measurements were performed in some of the compounds studied, as well as thermal characterization using DSC and TGA. Finally, experimental measurements of density on all those ILs have been performed, and for some of the samples in a broad temperature range (about 100 K). In spite of being very similar compounds from the chemical point of view, they present quite different physical properties, including optical, thermal and magnetic ones? Also, they show different oxidation states (one with +1, six with +2 and other three with +3). We guess that this family of ILs will have interesting applications, mainly for photonic devices
Empirical antibiotic therapy improves outcomes in mechanically ventilated patients with COVID-19: An emulated targeted trial within a prospective, multicentre cohort study
Ascorbic acid pre-treated quartz stimulates TNF-α release in RAW 264.7 murine macrophages through ROS production and membrane lipid peroxidation
<p>Abstract</p> <p>Background</p> <p>Inhalation of crystalline silica induces a pulmonary fibrotic degeneration called silicosis caused by the inability of alveolar macrophages to dissolve the crystalline structure of phagocytosed quartz particles. Ascorbic acid is capable of partially dissolving quartz crystals, leading to an increase of soluble silica concentration and to the generation of new radical sites on the quartz surface. The reaction is specific for the crystalline forms of silica. It has been already demonstrated an increased cytotoxicity and stronger induction of pro-inflammatory cyclooxygenase-2 (COX-2) by ascorbic acid pre-treated quartz (QA) compared to untreated quartz (Q) in the murine macrophage cell line RAW 264.7.</p> <p>Methods</p> <p>Taking advantage of the enhanced macrophage response to QA as compared to Q particles, we investigated the first steps of cell activation and the contribution of early signals generated directly from the plasma membrane to the production of TNF-α, a cytokine that activates both inflammatory and fibrogenic pathways.</p> <p>Results</p> <p>Here we demonstrate that TNF-α mRNA synthesis and protein secretion are significantly increased in RAW 264.7 macrophages challenged with QA as compared to Q particles, and that the enhanced response is due to an increase of intracellular ROS. Plasma membrane-particle contact, in the absence of phagocytosis, is sufficient to trigger TNF-α production through a mechanism involving membrane lipid peroxidation and this appears to be even more detrimental to macrophage survival than particle phagocytosis itself.</p> <p>Conclusion</p> <p>Taken together these data suggest that an impairment of pulmonary macrophage phagocytosis, i.e. in the case of alcoholic subjects, could potentiate lung disease in silica-exposed individuals.</p
Absence of Positive Selection on Centromeric Histones in Tetrahymena Suggests Unsuppressed Centromere-Drive in Lineages Lacking Male Meiosis
Centromere-drive is a process where centromeres compete for transmission through asymmetric "female" meiosis for inclusion into the oocyte. In symmetric "male" meiosis, all meiotic products form viable germ cells. Therefore, the primary incentive for centromere-drive, a potential transmission bias, is believed to be missing from male meiosis. In this article, we consider whether male meiosis also bears the primary cost of centromere-drive. Because different taxa carry out different combinations of meiotic programs (symmetric + asymmetric, symmetric only, asymmetric only), it is possible to consider the evolutionary consequences of centromere-drive in the context of these differing systems. Groups with both types of meiosis have large, rapidly evolving centromeric regions, and their centromeric histones (CenH3s) have been shown to evolve under positive selection, suggesting roles as suppressors of centromere-drive. In contrast, taxa with only symmetric male meiosis have shown no evidence of positive selection in their centromeric histones. In this article, we present the first evolutionary analysis of centromeric histones in ciliated protozoans, a group that only undergoes asymmetric "female" meiosis. We find no evidence of positive selection acting on CNA1, the CenH3 of Tetrahymena species. Cytological observations of a panel of Tetrahymena species are consistent with dynamic karyotype evolution in this lineage. Our findings suggest that defects in male meiosis, and not mitosis or female meiosis, are the primary selective force behind centromere-drive suppression. Our study raises the possibility that taxa like ciliates, with only female meiosis, may therefore undergo unsuppressed centromere drive
- …
