416 research outputs found
Microwave-assisted synthesis and electrochemical evaluation of VO2 (B) nanostructures
Understanding how intercalation materials change during electrochemical operation is paramount to optimizing their behaviour and function and in situ characterization methods allow us to observe these changes without sample destruction. Here we first report the improved intercalation properties of bronze phase vanadium dioxide VO2 (B) prepared by a microwave-assisted route which exhibits a larger electrochemical capacity (232 mAh g-1) compared with VO2 (B) prepared by a solvothermal route (197 mAh g-1). These electrochemical differences have also been followed using in situ X-ray absorption spectroscopy allowing us to follow oxidation state changes as they occur during battery operation
Rational synthesis of normal, abnormal and anionic NHC-gallium alkyl complexes : structural, stability and isomerization insights
Advancing the rational design of main-group N-heterocyclic carbene complexes, this study reports the synthesis, X-ray crystallographic and NMR spectroscopic characterisation of a novel series of Ga complexes containing neutral or anionic NHC ligands using the unsaturated carbene IPr (IPr = 1,3-bis-(2,6-di-isopropylphenyl)imidazol-2-ylidene). Starting from normal adduct GaR3·IPr (1) (R = CH2SiMe3), the addition of polar LiR led to the formation of NHC-stabilised gallate species IPr·LiGaR4 (2), resulting from co-complexation of the single-metal species. Contrastingly, reversing the order of addition of these organometallic reagents, by treating unsaturated free IPr, first with LiR followed by GaR3, furnished novel heteroleptic gallate (THF)2Li[:C{[N(2,6-iPr2C6H3)]2CHCGa(CH2SiMe3)3}] (3), which contains an anionic NHC ligand acting as an unsymmetrical bridge between the two metals, coordinating through its abnormal C4 position to Ga and through its normal C2 position to Li. Electrophilic interception studies of 3 using methyl triflate (MeOTf), methanol and imidazolium salt (IMes·HCl) led to the isolation and structural elucidation of the two novel neutral abnormal NHC (aNHC) complexes [CH3C{[N(2,6-iPr2C6H3)]2CHCGa(CH2SiMe3)3}] (4) and aIPr·GaR3 (5) (aIPr = HC{[N(2,6-iPr2C6H3)]2CHC}). These studies disclose the preference of the anionic IPr ligand present in 3 to react with electrophiles via its C2 position, leaving its Ga–C4 bond intact. Abnormal complex 5 can also be accessed by a thermally induced rearrangement of its normal isomer 1. Combining NMR spectroscopic and kinetic studies with DFT calculations, new light has been shed on this intriguing transformation, which suggests that it occurs via a dissociative mechanism, highlighting the importance of the donor ability of the solvent used in these thermal isomerizations as well as the steric bulk of the substituents on the NHC and the Ga reagent. These findings intimate that relief of the steric hindrance around Ga by forming an abnormal complex is a key driving force behind these rearrangements
Soft solution fluorine-free synthesis of anatase nanoparticles with tailored morphology
TiO2 nanoparticles with tailored morphology have been synthesized under exceptionally soft conditions. The strategy is based on the use of a non-aqueous alcoholic reaction medium in which water traces, coming either from the air (atmospheric water) or from an ethanol–water azeotropic mixture (ethanol 96%), are incorporated in order to accelerate hydrolysis of the Ti–precursor. Moreover, organic surfactants have been used as capping agents so as to tailor crystal growth in certain preferential directions. Combinations of oleic acid and oleylamine, which lead to the formation of another surfactant, dioleamide, are employed instead of fluorine-based compounds, thus increasing the sustainability of the process. As a result, TiO2 nanostructured hierarchical microspheres and individual nanoparticles with exposed high-energy facets can be obtained at atmospheric pressure and temperatures as low as 78 °C
Thioredoxin 1 modulates apoptosis induced by bioactive compounds in prostate cancer cells
Accumulating evidence suggests that natural bioactive compounds, alone or in combination with traditional chemotherapeutic agents, could be used as potential therapies to fight cancer. In this study, we employed four natural bioactive compounds (curcumin, resveratrol, melatonin, and silibinin) and studied their role in redox control and ability to promote apoptosis in androgen sensitive and insensitive prostate cancer cells. Here is shown that curcumin and resveratrol promote ROS production and induce apoptosis in LNCaP and PC-3. An increase in reactive species is a trigger event in curcumin-induced apoptosis and a consequence of resveratrol effects on other pathways within these cells. Moreover, here we demonstrated that these four compounds affect differently one of the main intracellular redox regulator, the thioredoxin system. Exposure to curcumin and resveratrol promoted TRX1 oxidation and altered its subcellular location. Furthermore, resveratrol diminished TRX1 levels in PC-3 cells and increased the expression of its inhibitor TXNIP. Conversly, melatonin and silibinin only worked as cytostatic agents, reducing ROS levels and showing preventive effects against TRX oxidation. All together, this work explores the effect of compounds currently tested as chemo-preventive agents in prostate cancer therapy, on the TRX1 redox state and function. Our work shows the importance that the TRX system might have within the differences found in their mechanisms of action. These bioactive compounds trigger different responses and affect ROS production and redox systems in prostate cancer cells, suggesting the key role that redox-related pathways might play in processes like differentiation or survival in prostate cancer. Keywords: Thioredoxin, Thioredoxin reductase, TXNIP, Prostate cancer, Redox signaling, Apoptosi
The solvation and dissociation of 4-benzylaniline hydrochloride in chlorobenzene
A reaction scheme is proposed to account for the liberation of 4-benzylaniline from 4-benzylaniline hydrochloride, using chlorobenzene as a solvent at a temperature of 373 K. Two operational regimes are explored: “closed” reaction conditions correspond to the retention of evolved hydrogen chloride gas within the reaction medium, whereas an “open” system permits gaseous hydrogen chloride to be released from the reaction medium. The solution phase chemistry is analyzed by 1H NMR spectroscopy. Complete liberation of solvated 4-benzylaniline from solid 4-benzylaniline hydrochloride is possible under “open” conditions, with the entropically favored conversion of solvated hydrogen chloride to the gaseous phase thought to be the thermodynamic driver that effectively controls a series of interconnecting equilibria. A kinetic model is proposed to account for the observations of the open system
Gram‐Scale Synthesis, Isolation and Characterisation of Sodium Organometallics: n BuNa and NaTMP
Free objects in Banach space theory
We survey recent progress on three relevant instances of free objects related
to Banach spaces: Lipschitz free spaces generated by metric spaces, holomorphic
free spaces generated by open sets and free Banach lattices generated by Banach
spaces. Our emphasis will be on the parallelisms among these developments.Comment: 24 page
A critical approach to Emotional Intelligence as a dominant discourse in the field of education
This article offers a critical analysis of emotional intelligence (EI) as a dominant discourse that establishes ways of understanding, managing, and learning about emotions in the field of education. The first section gives an overview of the recent interest in the emotional along with how the popularity of ideas associated with emotional intelligence derives from its ability to associate itself with other influential discourses that emerge from the brain sciences (neurology, cognitive psychology etc.). As part of this discussion, some of EI’s main qualities are questioned, for example, its neutrality, its potential to go beyond the dualist approaches that dominate traditional conceptions, and its proposal for a paradigm shift. The second part of the article examines the presence and impact of the discourse of emotional intelligence in the field of education in the form of mechanisms for measuring emotional intelligence and programmes of emotional intelligence or emotional literacy. The importance of educators’ emotional involvement is discussed, as is the problem of the subjectivating power of this discourse. It concludes with arguments that invite us to reflect and explore alternative ways of understanding and framing the emotional and emotional education.Este artículo presenta un análisis crítico de la Inteligencia Emocional como discurso dominante, a través del cual se concretan formas de entender, gestionar y aprender sobre las emociones en el ámbito educativo. En la primera parte se discute el reciente interés por lo emocional y cómo la popularidad de las ideas asociadas a la Inteligencia Emocional viene dada por su capacidad para asociarse con otros discursos de gran influencia que emergen desde las ciencias del cerebro (neurología, psicología cognitiva, etc.). Como parte de esta discusión se cuestionan algunas de sus cualidades principales como son su neutralidad, su potencial para transcender planteamientos dualistas que imperan en las concepciones tradicionales, así como su propuesta de cambio de paradigma. La segunda parte del artículo examina la presencia e implicaciones del discurso de Inteligencia Emocional en el contexto educativo a través de los mecanismos de medición de inteligencia emocional y los programas de educación o alfabetización emocional. También se discute la importancia de las implicaciones emocionales para los educadores, a la vez que se trata la problemática asociada al poder subjetivador de dicho discurso. Para concluir, se exponen argumentos que invitan a reflexionar y explorar formas alternativas de entender y plantear lo emocional y la educación emocional
Beyond liberal discourse: teachers’ conceptions of democracy and education in England and Spain
Spanish Government's State I+D Plan "Democracy in schools as the foundation of an education for Social Justice" [EDU2017-82688-P
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