Synthesis of polycycles by single or double domino nucleophilic substitution. Diels-Alder reaction

New hexacyclo and octacyclo compounds have been synthesized by a short route whose key step consists of a single or double domino nucleophilic substitution of neopentyl‐type iodides with potassium cyclopentadienide, followed by intramolecular Diels-Alder cycloaddition

\mu-\tau Symmetry and Maximal CP Violation

We argue the possibility that a real part of a flavor neutrino mass matrix only respects a mu-tau symmetry. This possibility is shown to be extended to more general case with a phase parameter \theta, where the mu-tau symmetric part has a phase of \theta/2. This texture shows maximal CP violation and no Majorana CP violation.Comment: 5 pages, version to appear in Phys. Lett.

Valoració pels alumnes dels ensenyaments del Campus de l'Alimentació de la UB de les activitats d'aprenentatge de l'assignatura de Fisiologia Humana

Podeu consultar la Vuitena trobada de professorat de Ciències de la Salut completa a: http://hdl.handle.net/2445/66524La Fisiologia Humana és una assignatura obligatòria de primer curs, comuna als graus de Nutrició Humana i Dietètica (NHD) i de Ciència i Tecnologia dels Aliments (CTA). L’avaluació de l’assignatura consisteix en diverses proves distribuïdes al llarg del curs, relacionades amb els continguts teòrics (examen final), les habilitats i competències pràctiques (examen pràctic), i el desenvolupament de competències transversals (anàlisi i síntesi d’articles científics). A més, i per tal d’estimular l’aprenentatge continuat, es fan proves d’avaluació formativa no acreditativa en forma de qüestionaris a través del campus virtual que anomenem bonus-test..

Determination of Neutrino Mass Texture for Maximal CP Violation

We show a general form of neutrino mass matrix (M), whose matrix elements are denoted by M_{ij} (i.j=e, mu, tau) as flavor neutrino masses, that induces maximal CP violation as well as maximal atmospheric neutrino mixing. The masses of M_{mu mu}, M_{tau tau} and M_{mu tau}+sigma M_{ee} (sigma =\pm 1) turn out to be completely determined by M_{e mu} and M_{e tau} for given mixing angles. The appearance of CP violation is found to originate from the interference between the mu-tau symmetric part of M and its breaking part. If |M_{e mu}|=|M_{e tau}|, giving either M_{e mu}=-sigma e^{i theta} M_{e tau} or M_{e mu}=-sigma e^{i theta}M*_{e tau} with a phase parameter theta, is further imposed, we find that |M_{mu mu}|=|M_{tau tau}|is also satisfied. These two constraints can be regarded as an extended version of the constraints in the mu-tau symmetric texture given by M_{e mu}=-sigma M_{e tau} and M_{mu mu}=M_{tau tau}. Majorana CP violation becomes active if arg(M_{mu tau})\neq arg(M_{e mu})+theta/2 for M_{e mu}=-sigma e^{i theta} M_{e tau} and if arg(M_{mu tau})\neq theta/2 for M_{e mu}=-sigma e^{i theta} M*_{e tau}.Comment: 10 pages, RevTex, typos corrected, minor clarifications added in Sec.3 and Sec.4, version to appear in Nucl. Phys.

Generation and Reactions of an Octacyclic Hindered Pyramidalized Alkene

Octacyclo[10.6.1.01,10.03,7.04,9.08,19.011,16.013,17]-nonadeca-5,8,14-triene (27), a hindered pyramidalized alkene, has been generated from a diiodide precursor. Contrary to the usual behavior of known pyramidalized alkenes, no Diels−Alder adducts were obtained from the present alkene when it was generated by different standard procedures in the presence of different dienes. However, products derived from the reduction, t-BuLi addition, condensation with the solvent, or dimerization were isolated from these reactions, depending on the conditions used to generate it. No [2 + 2] cross product among this pyramidalized alkene and tricyclo[3.3.1.03,7]non-3(7)-ene was formed when a mixture of the corresponding precursor diiodides was reacted with sodium amalgam. The analysis of selected geometrical and orbital parameters determined from quantum mechanical calculations indicates that the degree of pyramidalization of this alkene and its higher steric hindrance compared with other polycyclic pyramidalized alkenes may explain its peculiar reactivity

Quantifying the human diet in the crosstalk between nutrition and health by multi-targeted metabolomics of food and microbiota-derived metabolites

Background: Metabolomics is a powerful tool for investigating the association between nutrition and health status. Although urine is commonly employed for studying the metabolism and transformation of food components, the use of blood samples could be preferable to gain new insights into the bioavailability of diet-derived compounds and their involvement in health. However, the chemical complexity of blood samples hinders the analysis of this biological fluid considerably, which makes the development of novel and comprehensive analytical methods mandatory. Methods: In this work, we optimized a multi-targeted metabolomics platform for the quantitative and simultaneous analysis of 450 food-derived metabolites by ultra-high performance liquid chromatography coupled to tandem mass spectrometry. To handle the chemical complexity of blood samples, three complementary extraction methods were assayed and compared in terms of recovery, sensitivity, precision and matrix effects with the aim of maximizing metabolomics coverage: protein precipitation, reversed solid-phase extraction, and hybrid protein precipitation with solid-phase extraction-mediated phospholipid removal. Results: After careful optimization of the extraction conditions, protein precipitation enabled the most efficient and high-throughput extraction of the food metabolome in plasma, although solid-phase extraction-based protocols provided complementary performance for the analysis of specific polyphenol classes. The developed method yielded accurate recovery rates with negligible matrix effects, and good linearity, as well as high sensitivity and precision for most of the analyzed metabolites. Conclusions: The multi-targeted metabolomics platform optimized in this work enables the simultaneous detection and quantitation of 450 dietary metabolites in short-run times using small volumes of biological sample, which facilitates its application to epidemiological studies

El bonus-test. Una experiència d’avaluació formativa a través del Campus virtual

La Fisiologia Humana és una assignatura comuna dels graus de Nutrició Humana i Dietètica (NHD) i de Ciència i Tecnologia dels Aliments (CTA), que es va posar en marxa el curs 2010-11. Ja des de l’inici vàrem plantejar l’avaluació de l’assignatura de forma continuada; l’objectiu és que els estudiants aprenguin continuadament. El curs incorpora activitats d’avaluació no acreditativa, per estimular l’estudi continuat i, per tant, el seguiment correcte de l’assignatura. Es tracta d’un conjunt de deu qüestionaris que es fan setmanalment a través del Campus Virtual i que aporten una bonificació a la nota final: els anomenem BONUS-TEST. Aquesta experiència l’hem portat a terme des que es va iniciar l’assignatura fins el curs actual

Graphitic Carbon Nitride (C3N4) Reduces Cadmium and Arsenic Phytotoxicity and Accumulation in Rice (Oryza sativa L.)

The present study investigated the role of graphitic carbon nitride (C3N4) in alleviating cadmium (Cd)- and arsenic (As)-induced phytotoxicity to rice (Oryza sativa L.). A high-temperature pyrolysis was used to synthesize the C3N4, which was characterized by transmission electron microscopy, Fourier-transform infrared spectroscopy, and dynamic light scattering. Rice seedlings were exposed to C3N4 at 50 and 250 mg/L in half-strength Hoagland’s solution amended with or without 10 mg/L Cd or As for 14 days. Both Cd and As alone resulted in 26–38% and 49–56% decreases in rice root and shoot biomass, respectively. Exposure to 250 mg/L C3N4 alone increased the root and shoot fresh biomass by 17.5% and 25.9%, respectively. Upon coexposure, Cd + C3N4 and As + C3N4 alleviated the heavy metal-induced phytotoxicity and increased the fresh weight by 26–38% and 49–56%, respectively. Further, the addition of C3N4 decreased Cd and As accumulation in the roots by 32% and 25%, respectively, whereas the metal contents in the shoots were 30% lower in the presence of C3N4. Both As and Cd also significantly altered the macronutrient (K, P, Ca, S, and Mg) and micronutrient (Cu, Fe, Zn, and Mn) contents in rice, but these alterations were not evident in plants coexposed to C3N4. Random amplified polymorphic DNA analysis suggests that Cd significantly altered the genomic DNA of rice roots, while no difference was found in shoots. The presence of C3N4 controlled Cd and As uptake in rice by regulating transport-related genes. For example, the relative expression of the Cd transporter OsIRT1 in roots was upregulated by approximately threefold with metal exposure, but C3N4 coamendment lowered the expression. Similar results were evident in the expression of the As transporter OsNIP1;1 in roots. Overall, these findings facilitate the understanding of the underlying mechanisms by which carbon-based nanomaterials alleviate contaminant-induced phyto- and genotoxicity and may provide a new strategy for the reduction of heavy metal contamination in agriculture

Two Categories of Approximately mu-tau Symmetric Neutrino Mass Textures

Our approximately \mu-\tau symmetric neutrino mass textures fall into two different categories, whose behaviors in the \mu-\tau symmetric limit are characterized by either \sin(theta_{13})->0 (referred to as C1)), or \sin(theta_{12})->0 (referred to as C2)). We present ten phenomenologically viable neutrino mass textures: two for the normal mass hierarchy, three for the inverted mass hierarchy, and five for the quasi degenerate mass pattern. Tiny \mu-\tau symmetry breaking ensures that \sin^2(theta_{13}) << 1 for C1), and \Delta m^2_\odot/\Delta m^2_{atm} (\equiv R) << 1 for C2). A correlation among small quantities is provided by \cos 2(theta_{23}) \sim \sin(theta_{13}) for C1), and by either \cos(2theta_{23}) \sim R, or \cos(2theta_{23})\sin(theta_{13}) \sim R for C2). It is further shown that \tan(2theta_{12}) \sim \cos(2theta_{23})/\sin(theta_{13}) is satisfied for C2). We find specific properties for each mass ordering, which are discussed in this article.Comment: 31 pages, 15 figures (High-resolution figures can be downloaded from http://www.sp.u-tokai.ac.jp/~yasue/two_categories_of.pdf.tar.gz

Guía con prompts para profesores y estudiantes

Guía de uso de ChatGPT para la clase de ELE diseñada exclusivamente para profesores y estudiantes de ELE en busca de mejorar tus habilidades en español con esta herramienta de IA Generativa. Incluye prompts y ejemplos de uso e ideas para llevar al aula. Además, aporta ideas para desarrollar estrategias para una actitud crítica en la IA Generativ