A Platinum molecular complex immobilised on the surface of graphene as active catalyst in alkyne hydrosilylation

Abstract A platinum complex bearing a N‐heterocyclic carbene (NHC) ligand functionalised with a pyrene‐tag is immobilised onto the surface of reduced graphene oxide (rGO). The hybrid material composed of an organometallic complex and a graphene derivative is ready available in a single‐step process under mild reaction conditions. This methodology preserves the inherent properties of the active catalytic centre and the support. The platinum hybrid material is an efficient catalyst in hydrosilylation of alkynes and can be recycled and reused for ten runs without significant loss of activity due to its high stability. Interestingly, the catalytic properties of the platinum complex are enhanced after immobilisation onto graphene. The influence of graphene in hydrosilylation of alkynes is discussed

Efecto del Rootip-Calcio en la calidad y estatus nutricional de manzanas tipo Golden

4 Pags.- 1 Tabl.- 2 Figs.La deficiencia de calcio en el fruto es la principal causa de aparición del bitter-pit. Tradicionalmente se han aplicado tratamientos foliares, durante el desarrollo del fruto para incrementar su contenido en calcio y así reducir la incidencia de esta fisiopatía durante el almacenamiento. Sin embargo, estas aspersiones que generalmente contienen cloruro, nitrato de calcio, u otras formulaciones, no son del todo efectivas para disminuir los niveles de incidencia. En este trabajo se plantea estudiar la calidad de fruto y el estatus nutricional de manzanos Golden tratados con Rootip-Ca. Este producto es una nueva formulación de calcio que contiene 2,5% de aminoácidos libres, y que se aplica por vía radicular. Como resultado más relevante puede citarse que, en una de las parcelas utilizadas en el estudio que sufre endémicamente altos porcentajes de esta fisiopatía, el tratamiento con Rootip-Ca hizo descender en un 17% la incidencia de bitter pit a los 117 días de almacenamiento de los frutos en cámara fríaEste trabajo ha sido financiado por un contrato de asistencia técnica CSIC-ALTINCO.Peer reviewe

El fuego como agente tafonómico: análisis antropológico forense de marcas de corte relacionadas con el desmembramiento en restos óseos cremados

Introducción: La antropología forense es un área de conocimiento vinculada a la medicina legal y a la antropología física que se encarga del estudio de los restos óseos sin identificar y de esclarecer las circunstancias que rodean el fallecimiento. Tanto el desmembramiento como la cremación son dos alteraciones tafonómicas que complican el examen antropológico y el análisis e interpretación de evidencias de traumatismo. Su impacto negativo por separado es conocido, pero se han realizado escasas investigaciones para estudiar los efectos de la exposición al fuego en las partes del cuerpo amputadas. Hipótesis y objetivos: El fuego afecta a la detección e interpretación del traumatismo cortante en casos de desmembramiento. Los objetivos concretos de esta tesis doctoral fueron: (1) Calcular la prevalencia de casos de desmembramiento en relación a los homicidios intencionales, y el número de casos en los cuales los restos desmembrados fueron alterados con fuego; (2) analizar la influencia de la alteración post-desmembramiento en la investigación antropológica; (3) desarrollar una guía visual y un diagrama de flujo para distinguir entre fracturas inducidas por el fuego y trauma cortante y (4) examinar su fiabilidad y repetibilidad; (5) calcular el porcentaje de supervivencia post-cremación de las marcas de corte realizadas y (6) explorar las variables que afectan a su supervivencia; (7) examinar la distorsión que el fuego inflige en la morfología, longitud, anchura y rugosidad de marcas de corte comparando las lesiones antes y después de la cremación; y (8) relacionar estas variaciones con cada tipo de instrumento..

Synthesis and reactivity of new silyl-substituted monocyclopentadienyl molybdenum and tungsten complexes

The functionalized silylated cyclopentadienyl molybdenum and tungsten complexes [MCpCl(CO)3H] (M=Mo, W; CpCl=η5-C5H4SiMe2Cl) are prepared easily from the reaction of [M(CO)3(NCMe)3] with C5H5SiMe2Cl in refluxing THF, via C–H activation and H transfer to the metal centre. Metathetical replacement of hydride by chloride is readily achieved when their methylene chloride solutions are treated with a few milliliters of CCl4 to give the chloro complexes [MCpCl(CO)3Cl] (M=Mo, W). The chloro–molybdenum complexes react with 1/2 equivalent of deoxygenated water to give the corresponding dinuclear complexes [{Mo(CO)3X}2(μ-CpOCp)], (X=H, Cl; CpOCp=η5-C5H4-SiMe2-O-SiMe2-η5-C5H4), whereas their reaction with one equivalent of anhydrous LiOH in toluene leads to selective substitution of the silicon-bonded chlorine atom to give the hydroxo complexes [MoCpOH(CO)3X] (X=H, Cl; CpOH=η5-C5H4SiMe2OH). These hydroxosilyl complexes can be transformed into the dinuclear compounds [{Mo(CO)3X}2(μ-CpOCp)] by heating (50°C, 2 h) or by their reaction with one equivalent of the respective hydrido and chloro derivatives [MoCpCl(CO)3X]. Total decarbonylation of the hydrido compounds results from oxidation with a stoichiometric amount of PCl5 to give the paramagnetic molybdenum(V) and tungsten(V) complexes [MCpClCl4] (M=Mo, W). Reactions of these complexes with one equivalent of NH2R in the presence of NEt3 yield the imido derivatives [MCpCl(NR)Cl2] (M=Mo, R=2,6-Me2-Ph; M=W, R=tBu) and subsequent oxidation of the tungsten complex with 1/2 equivalent of PCl5 gives [WCpCl(NtBu)Cl3]. Reduction of [MoCpClCl4] with two equivalents of Na/Hg gives the dinuclear molybdenum(III) complex [MoCpCl]2(μ-Cl)4. All of the reported compounds were characterized by elemental analysis and 1H- and 13C NMR-spectroscopy.The authors acknowledge DGICYT (project PB92-0178-C) for financial support

Echinococcosis in Mexico — A Story Worth Sharing

At the beginning of the XXI millennium, while working at a general hospital in Mexico City, a young lady arrived with a previous diagnosis of liver amebiasis given six years earlier. Different treatments in various clinical settings were provided. In the hospital, the first approach was an ultrasound study and unexpectedly an Echinococcus granulosus cyst was clearly identified. The patient received adequate treatment and accepted to participate as the index case in an epidemiological survey performed in her community. Inhabitants, dogs, cattle, pigs, and sheep were studied; cysts in humans, pigs, and sheep were searched by ultrasound and dogs by coproantigens, livestock, and dogs were negative for larval or adult stages respectively. The use of ultrasound allowed the detection of two cases (overall prevalence 0.95). DNA of the patient’s cyst recovered by surgery was purified, amplified, sequenced, and multiple alignments were performed and analyzed, identifying to Echinococcus ortleppi. Subsequently, in a population genetics study focused to evaluate the presence and genetic variability of the intestinal tapeworm in dogs and of cystic echinococcosis in livestock in central areas from Mexico, Echinococcus canadensis G7 was identified and was found only in pigs. Based on a genetic network analysis, the following deductions were made: 1) E. canadensis G7 in Mexico is very diverse and was probably introduced from abroad several times from different sources and from different countries; 2) G7 haplotypes grouped in the North American wildlife cluster are placed far from Mexican isolates, thus they might be ruled out as sources of introduction to Mexico; and 3) the species status for G7, formally named E. canadensis, is still controversial, because biologically different strains (G6 to G10) are currently unified, though ecological and genetic data appear to indicate otherwise

Influence of PLA Filament Conditions on Characteristics of FDM Parts

Additive manufacturing technologies play an important role in Industry 4.0. One of the most prevalent processes is fused deposition modelling (FDM) due to its versatility and low cost. However, there is still a lack of standardization of materials and procedures within this technology. This work aims to study the relationship of certain operating parameters and the conditions of poly(lactic acid) (PLA) polymer with the results of the manufactured parts in dimensional terms, surface quality, and mechanical strength. In this way, the impact of some material characteristics is analyzed, such as the pigmentation of the material and the environmental humidity where it has been stored. The manufacturing parameter that relates to these properties has been the extrusion temperature since it is the most influential in this technology. The results are quite affected especially by humidity, being a parameter little studied in the literature.This research was funded by the Spanish Government via the Ministry of Economy, Industry and Competitiveness, the European Union (FEDER/FSE), and the Andalusian Government (PAIDI), project MINERVA

Paleomagnetic and paleoenvironmental implications of magnetofossil occurrences in late Miocene marine sediments from the Guadalquivir Basin, SW Spain

Although recent studies have revealed more widespread occurrences of magnetofossils in pre-Quaternary sediments than have been previously reported, their significance for paleomagnetic and paleoenvironmental studies is not fully understood. We present a paleo- and rock-magnetic study of late Miocene marine sediments recovered from the Guadalquivir Basin (SW Spain). Well-defined paleomagnetic directions provide a robust magnetostratigraphic chronology for the two studied sediment cores. Rock magnetic results indicate the dominance of intact magnetosome chains throughout the studied sediments. These results provide a link between the highest-quality paleomagnetic directions and higher magnetofossil abundances. We interpret that bacterial magnetite formed in the surface sediment mixed layer and that these magnetic particles gave rise to a paleomagnetic signal in the same way as detrital grains. They, therefore, carry a magnetization that is essentially identical to a post-depositional remanent magnetization, which we term a bio-depositional remanent magnetization. Some studied polarity reversals record paleomagnetic directions with an apparent 60-70 kyr recording delay. Magnetofossils in these cases are interpreted to carry a biogeochemical remanent magnetization that is locked in at greater depth in the sediment column. A sharp decrease in magnetofossil abundance toward the middle of the studied boreholes coincides broadly with a major rise in sediment accumulation rates near the onset of the Messinian salinity crisis (MSC), an event caused by interruption of the connection between the Mediterranean Sea and the Atlantic Ocean. This correlation appears to have resulted from dilution of magnetofossils by enhanced terrigenous inputs that were driven, in turn, by sedimentary changes triggered in the basin at the onset of the MSC. Our results highlight the importance of magnetofossils as carriers of high-quality paleomagnetic and paleoenvironmental signals even in dominantly terrigenous sediments.This study was funded by the Guadaltyc project (MINECO, CGL2012–30875), ARC grant DP120103952, and NSFC grant 41374073

CHARACTERIZATION OF NH4-BEARING MICAS IN CARPHOLITE METAPELITES FROM AMORGOS (GREECE)

1 página. Resumen de la comunicación presentada en European Union of Geosciences XII (Niza, Francia, 6-11 abril 2003)Phengitic micas from some HP setting carpholite-bearing rocks in the Alpine domain have been shown to have anomalous low-K content (0–9 to 0.55 pfu.) which may in part, be explained by a pirophilitic(illitic) substitution. Preliminary EMPA analyses show that phengitic micas from Amorgos(Greece) represent one of the most extreme cases of an interlayer deficit in this set of samples, interlayer content ranges from 0.65 to 0.55 pfu.Peer reviewe