MasterChem: Cooking 2D-polymers

2D-polymers are still dominated by graphene and closely related materials such as boron nitride, transition metal sulphides and oxides. However, the rational combination of molecules with suitable design is already showing the high potential of chemistry in this new research field. The aim of this feature article is to illustrate, and provide some perspectives, the current state-of-the-art in the field of synthetic 2D-polymers showing different alternatives to prepare this novel type of polymers based on the rational use of chemistry. This review comprises a brief revision of the essential concepts, the strategies of preparation following the two general approaches, bottom-up and top-down, and a revision of the promising seminal properties showed by some of these nanomaterials.Financial support from Spanish MINECO (MAT2013-46753-C2-1-P and MAT2013-46502-C2-2-P). D. R. thanks the Spanish MECD for a FPU gran

New forms of masculinity in Western films: The end of the Marlboro Man?

Westerns are one of the most masculine and stereotypical of film genres. In a social and film context where gender equality is increasingly important, it is worth looking at the evolution of the genre in recent years. Especially because, as André Bazin said, the Western is “cinema par excellence” (1966) and its analysis allows a reflection on cinema itself. Taking the figure of the Marlboro Man as a prototype, this study carries out an analysis of three selected case studies: Brokeback Mountain, Jane Got a Gun and Godless, two films and a miniseries with main characters that do not follow heteronormative masculinity. Ang Lee’s work broke new ground not only in Westerns but also in industrial cinema by making homosexuality visible, while Gavin O’Connor’s showed the possibility of a woman playing the leading role in a classic Western. The miniseries produced by Netflix combines both by giving leading roles to female characters, some of them gay, while reflecting on homosexuality. It was noted that the portrayal of masculinity in Western films remains valid in all three cases, but it allows women and homosexuals to access leading roles, often by acquiring typically masculine attributes

Influencia de la composición petrológica y procedencia en la albitización de las areniscas sinrift del Cretácico inferior, Cuenca del Maestrazgo, Cadena Ibérica

Lower Cretaceous sandstones from the Maestrat Basin are characterized by differences in detrital composition, provenance and degree of albitized feldspars (partial to complete). Petrological composition of Lower Cretaceous sandstones revealed a mixed provenance from plutonic and metamorphic source areas. A progressively major influence of granitic source rocks was detected from the lowermost Mora petrofacies toward the uppermost El Castellar and Camarillas petrofacies. Albitization of detrital feldspars occurred in all the studied sandstones, but feldspars were completely albitized in the lowermost Mora Fm. and only partially albitized in the overlying Castellar and Camarillas formations. However, all the Lower Cretaceous sandstones underwent, approximately, the same burial and thermal conditions (119-134ºC; based on vitrinite reflectance and thermal modelling). The decrease in replacive albite/detrital feldspars ratio from the lowermost Mora Fm. toward the uppermost Camarillas Fm. was related to differences in detrital composition and provenance of sandstones. Albitization was pervasive in the Mora Fm. sandstones because of its dominant metamorphic source areas, which implies a relative low abundance of K-feldspar compared to plagioclase. In contrast, the abundance of K-feldspars in Castellar and Camarillas formations prevented the complete albitization of feldspars. Thus, differences in original composition and provenance of sandstones influenced significantly the different degree of albitization for comparable burial and thermal rates.Las areniscas del Cretácico inferior de la Cuenca del Maestrazgo presentan diferencias en su composición detrítica, procedencia y grado de albitización de los feldespatos. La composición petrológica indica una mezcla de aportes de rocas metamórficas (dominantes en la Fm. Mora, Berriansiense-Valanginiense) y plutónicas (progresiva mayor contribución hacia las fms. Castellar y Camarillas, Valanginiense-Barremiense). La albitización de los feldespatos detríticos se observa en todas las areniscas, pero sólo la Fm. Mora presenta feldespatos completamente albitizados, mientras que las fms. Castellar y Camarillas la albitización es parcial. Uno de los factores que controla el proceso de albitización es la temperatura, sin embargo, todas las areniscas del Cretácico inferior estuvieron sometidas a condiciones de enterramiento y temperatura similares (119-134ºC; basadas en reflectancia de vitrinitas y modelización térmica). La disminución de grado de albitización hacia las fms. Castellar y Camarillas estaría relacionada con las diferencias en composición y procedencia de las areniscas. La albitización fue completa en la Fm. Mora debido a la mayor presencia de aportes de rocas metamórficas, lo que implica una mayor abundancia de plagioclasas. Por el contrario, la mayor abundancia de feldespato-K en las fms. Castellar y Camarillas impidió la completa albitización de los feldespatos. Por tanto, las diferencias en la composición y procedencia de las areniscas influyeron significativamente en el grado de albitización de los feldespatos en condiciones similares de enterramiento y temperaturaDepto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEMinisterio de Educación y Ciencia (MEC)pu

High-pressure phase transformations, pressure-induced amorphization, and polyamorphic transition of the clathrate Rb6.15Si46

International audienceThe type-I clathrate Rb6.15Si46 with partly empty cage sites has been studied up to 36 GPa using Raman spectroscopy, synchrotron x-ray diffraction in diamond-anvil cells, and ab initio total-energy and lattice-dynamics calculations. A first phase transition is observed at 13±1 GPa and a "volume collapse" transition within the clathrate structure is then observed at 24±1 GPa. Pressure-induced amorphization into a high-density amorphous (HDA) state occurs above P=33±1 GPa. The HDA form transforms into a low-density amorphous polymorph during decompression. During the compression study using angle dispersive synchrotron x-ray diffraction techniques we measured bulk modulus parameters for rocksalt-structured TaO, included adventitiously in the clathrate sample [K0=293(3) GPa and K′0=5.4(3)]

Tris(2-pyridyl) Bismuthines: Coordination Chemistry, Reactivity, and Anion-Triggered Pyridyl Coupling

Producción CientíficaA series of new tris(2-pyridyl) bismuthine ligands of the type [Bi(2-py′)3] have been prepared, containing a range of substituents at various positions within their pyridyl rings (py′). They can act as intact ligands or, as a result of the low C–Bi bond energy, exhibit noninnocent reactivity in the presence of metal ions. Structural studies of Li+ and Ag+ complexes show that the coordination to metal ions using their pyridyl-N atoms and to anions using the Lewis acidity of their Bi(III) centers can be modified by the presence of substituents within the 2-pyridyl rings, especially at the 6- or 3-positions, which can block the donor-N or Lewis acid Bi sites. Electron withdrawing groups (like CF3 or Br) can also severely reduce their ability to act as ligands to metal ions by reducing the electron donating ability of the pyridyl-N atoms. Noninnocent character is found in the reactions with Cu+ and Cu2+, resulting in the coupling of pyridyl groups to form bipyridines, with the rate of this reaction being dependent on the anion present in the metal salts. This leads to the formation of Bi(III)/Cu(I) complexes containing hypervalent [X2Bi(2-R-py)]− (X = Cl, Br) anions. Alternatively, the tris(2-pyridyl) bismuthine ligands can act as 2-pyridyl transfer reagents, transferring 2-py groups to Au(I) and Fe(II).Ministerio de Ciencia, Innovación y Universidades (project numbers PGC2018-096880-A-I00, MCIU/AEI/FEDER, UE and PGC2018-099470-B-I00,MCIU/AEI/FEDER, UE)Ministerio de Economía, Industria y Competitividad (Project RYC-2015-19035

Beliefs in conspiracy theories about COVID-19 vaccines in the Andean Community of Nations

Los estudios sobre aceptación y rechazo hacia las vacunas, así como la creencia en teorías conspirativas, y la falta de confianza en los gobiernos y la ciencia, han sido importantes para analizar el proceso de vacunación contra el COVID-19 a nivel mundial, pero han sido bastante limitados, hasta el momento, para el caso de América Latina. En este sentido, el objetivo de este trabajo consiste en describir el grado de aceptación o no a ciertas creencias de conspiración sobre las vacunas contra la COVID-19 en una muestra de países miembros de la Comunidad Andina de Naciones (CAN): Bolivia, Colombia, Ecuador y Perú. Se diseñó un estudio transversal descriptivo en el que participaron 1835 personas de Bolivia, Colombia, Ecuador y Perú. Para la evaluación de estas creencias se utilizó la Escala de Creencias de Conspiración de Vacunas COVID-19 (ECCV-COVID, Caycho-Rodríguez et al., 2022a). Los resultados indican que, el Perú presenta el mayor puntaje promedio de creencias de conspiración sobre las vacunas contra la COVID19. Además, en los 4 países el menor grado de aceptación es con la creencia sobre “Vacunar a los niños contra la COVID-19 es perjudicial y este hecho está ocultado”. En Colombia, Ecuador y Perú el mayor grado de aceptación está referida a la creencia conspirativa referida a que “La información sobre la seguridad de las vacunas contra la COVID-19 a menudo se inventan”. Finalmente, en Bolivia, el mayor grado de aceptación es con la creencia de que “Las empresas farmacéuticas ocultan los peligros de las vacunas contra la COVID-19”. Los resultados presentados en este estudio son los primeros que se conoce de forma genérica en población latinoamericana, y particularmente, en la población Andina.Studies on the acceptance and rejection of vaccines, as well as the belief in conspiracy theories, and the lack of trust in governments and science, have been important to analyze the vaccination process against COVID-19 worldwide, but they have been quite limited, so far, in the case of Latin America. In this sense, the objective of this work is to describe the degree of acceptance or not of certain conspiracy beliefs about vaccines against COVID-19 in a sample of countries members in the Andean Community of Nations (CAN): Bolivia, Colombia, Ecuador and Peru. A descriptive cross-sectional study was designed in which 1835 people from Bolivia, Colombia, Ecuador and Peru participated. To evaluate these beliefs, the COVID-19 Vaccine Conspiracy Belief Scale (ECCV-COVID, Caycho-Rodríguez et al., 2022a) was used. The results indicate that Peru has the highest average score of conspiracy beliefs about vaccines against COVID-19. In addition, in the 4 countries, the lowest degree of acceptance is with the belief that "Vaccinating children against COVID-19 is harmful and this fact is hidden". In Colombia, Ecuador and Peru, the highest degree of acceptance is related to the conspiratorial belief that "Information on the safety of vaccines against COVID-19 is often invented." Finally, in Bolivia, the highest degree of acceptance is with the belief that "Pharmaceutical companies hide the dangers of vaccines against COVID-19". The results presented in this study are the first known generically in the Latin American population, and particularly in the Andean population.Fil: Caycho Rodríguez, Tomás. Universidad Privada del Norte; PerúFil: Gallegos de San Vicente, Miguel Omar. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Pontifícia Universidade Católica de Minas Gerais; BrasilFil: Valencia, Pablo D.. Facultad de Estudios Superiores Iztacala; MéxicoFil: Vilca, Lindsey W.. Universidad Norbert Wiener; PerúFil: Moreta Herrera, Rodrigo. Pontificia Universidad Católica del Ecuador; EcuadorFil: Puerta Cortés, Diana Ximena. Universidad de Ibagué; ColombiaFil: Tapia, Bismarck Pinto. Universidad Catolica Boliviana; Bolivi