1-Heptene hydroformylation over phosphinated silica-anchored rhodium thiolate complexes.

[EN]The rhodium (I) pentaflurophenylthiolate complexes [Rh(μ-SC6F5)(COD)]2 and [Rh(μ-SC6F5)(CO)2]2 were anchored on phosphinated silica. These catalysts were tested in the hydroformylation reaction of 1-heptene in toluene at 343–393 K using a gas feed ratio of CO:H2=1 mole. The conversion of 1-heptene versus the reaction time followed S-shaped curves in which the induction period depended on the catalyst precursor and number of cycles in the reaction. Selectivity towards linear aldehyde was high, although the extent of isomerisation to internal olefins was found to be important. The addition of free PPh3 to the reaction medium markedly increased the yield to linear aldehyde but the rate of the reaction appeared to be retarded. The results are compared with those obtained on using these complexes in homogeneous phase under similar conditions. The effects of temperature, pressure and the phosphine/Rh mole ratio on the reaction rate and selectivity are discussed

Silicoaluminates as “support activator” systems in olefin polymerization processes

In this work we report the polymerization behaviour of natural clays (montmorillonites, MMT) as activating supports. These materials have been modified by treatment with different aluminium compounds in order to obtain enriched aluminium clays and to modify the global Brönsted/Lewis acidity. As a consequence, the intrinsic structural properties of the starting materials have been changed. These changes were studied and these new materials used for ethylene polymerization using a zirconocene complex as catalyst. All the systems were shown to be active in ethylene polymerization. The catalyst activity and the dependence on acid strength and textural properties have been also studied. The behaviour of an artificial silica (SBA 15) modified with an aluminium compound to obtain a silicoaluminate has been studied, but no ethylene polymerization activity has been found yet

Use of membrane hybrid processes for phenol recovery/separation from industrial wastewater

Phenol is a raw material that is used for the manufacture of several products of industrial origin; consequently, an excessive amount of phenolic effluentsis obtained, giving rise to a marked problem of pollution, since phenol causes toxic effects in the environment. Therefore, the development of feasible treatment methods has been a key challenge to reduce pollution related to this substance. Today, hybrid membrane systems contain new andseveral alternatives that have been developed for there covery, elimination and degradation of phenol. The objective of this short communication is to provide an overview of the scope of these hybrid systems for their application in the treatment of phenolic effluents

Rhodium(I) fluorothiolate complexes as hydroformylation catalyst precursors. Crystal structure of two polymorphs of trans-[Rh(SC6F5)(CO)(PPh3)2]

[EN]The perfluorothiolate dinuclear compounds [Rh( ]A,-SC6E5XCOD)] 2 1 and [Rh( ]J~-SC6F5XCO)2] 2 2 react with PPh 3 to give monomeric and dimeric complexes, the particular product depending upon the PR3/Rh ratio and reaction conditions. Reaction of 2 with 2 moles of PPh 3 renders cis-7 and trans-[Rh(/x-SC6Fs)((CO)(PPh3)] z 8, while with 4 moles of PPh 3 trans[Rh(SC6FsXCO)(PPh3)E]lOa is obtained. This latter product can otherwise be prepared by C1 metathesis from trans-[RhCl(CO(PPh3) 2] in toluene. This same reaction in dichloromethane however yields the cis isomer 10b. When a larger excess of PPh 3 is used, a mixture of compounds 11a and llb is formed. An X-ray crystal structure study shows trans[Rh(SC6Fs)(CO)(PPh3) 2] to exit as two polymorphs. 11a crystallises in the space group P2t/n of the monoclinic system with a = 12.489(1), b = 15.430(5), c = 19.719(1) A, te = y= 90, /3 = 92.84(1) °, and llb is triclinic, space group P1 with a = 9.764(2), b = 12.197(6), c = 17.880 ]k, a = 100.18(5), /3 = 101.92(2), T= 113.61(2) °. Both PPh 3 ligands are mutually trans and the difference in u(CO) stretching frequencies, 1989 and 1939 cm -1, can be explained in terms of o-phenyl H... CO interactions in the latter. The [Rh(/z-SC6Fs)(COD)] 2 1 and [Rh(/.£-SC6FsXCO)2] 2 2/nPPh 3 systems have been studied as catalyst precursors for the hydroformylation of l-heptene in toluene at 30 bar and 343 K. Selectivity towards the linear aldehyde is enhanced when dimeric complexes are used

GSK-3β orchestrates the inhibitory innervation of adult-born dentate granule cells in vivo

Adult hippocampal neurogenesis enhances brain plasticity and contributes to the cognitive reserve during aging. Adult hippocampal neurogenesis is impaired in neurological disorders, yet the molecular mechanisms regulating the maturation and synaptic integration of new neurons have not been fully elucidated. GABA is a master regulator of adult and developmental neurogenesis. Here we engineered a novel retrovirus encoding the fusion protein Gephyrin:GFP to longitudinally study the formation and maturation of inhibitory synapses during adult hippocampal neurogenesis in vivo. Our data reveal the early assembly of inhibitory postsynaptic densities at 1 week of cell age. Glycogen synthase kinase 3 Beta (GSK-3β) emerges as a key regulator of inhibitory synapse formation and maturation during adult hippocampal neurogenesis. GSK-3β-overexpressing newborn neurons show an increased number and altered size of Gephyrin+ postsynaptic clusters, enhanced miniature inhibitory postsynaptic currents, shorter and distanced axon initial segments, reduced synaptic output at the CA3 and CA2 hippocampal regions, and impaired pattern separation. Moreover, GSK-3β overexpression triggers a depletion of Parvalbumin+ interneuron perineuronal nets. These alterations might be relevant in the context of neurological diseases in which the activity of GSK-3β is dysregulatedPID2020-113007RB-I00, SAF-2017-82185-R, PID2020-112824GB-10

Methods to study adult hippocampal neurogenesis in humans and across the phylogeny

The hippocampus hosts the continuous addition of new neurons throughout life—a phenomenon named adult hippocampal neurogenesis (AHN). Here we revisit the occurrence of AHN in more than 110 mammalian species, including humans, and discuss the further validation of these data by single-cell RNAseq and other alternative techniques. In this regard, our recent studies have addressed the long-standing controversy in the field, namely whether cells positive for AHN markers are present in the adult human dentate gyrus (DG). Here we review how we developed a tightly controlled methodology, based on the use of high-quality brain samples (characterized by short postmortem delays and ≤24 h of fixation in freshly prepared 4% paraformaldehyde), to address human AHN. We review that the detection of AHN markers in samples fixed for 24 h required mild antigen retrieval and chemical elimination of autofluorescence. However, these steps were not necessary for samples subjected to shorter fixation periods. Moreover, the detection of labile epitopes (such as Nestin) in the human hippocampus required the use of mild detergents. The application of this strictly controlled methodology allowed reconstruction of the entire AHN process, thus revealing the presence of neural stem cells, proliferative progenitors, neuroblasts, and immature neurons at distinct stages of differentiation in the human DG. The data reviewed here demonstrate that methodology is of utmost importance when studying AHN by means of distinct techniques across the phylogenetic scale. In this regard, we summarize the major findings made by our group that emphasize that overlooking fundamental technical principles might have consequences for any given research fieldAssociation for Frontotemporal Degeneration; Banco de Santander; Center for Networked Biomedical Research on Neurodegenerative Diseases; Consejo Nacional de Ciencia y Tecnología (CONACYT), Grant/Award Number: 385084; European Research Council, Grant/Award Number: ERC-CoG2020-101001916; Fundacion Ram on Areces; Secretaria de Educacion, Ciencia Tecnología e Innovacion (SECTEI) of the Regional Government of Ciudad de México (CDMX), Grant/Award Number: SECTEI/159/2021; Spanish Ministry of Economy and Competitiveness, Grant/Award Numbers: PID2020-113007RB-I00, RYC-2015-171899, SAF-2017-82185-R; The Alzheimer's Association, Grant/Award Numbers: 2015-NIRG-340709, AARG-17-528125, AARG-17-528125-RAPI

Activity-Dependent Reconnection of Adult-Born Dentate Granule Cells in a Mouse Model of Frontotemporal Dementia

Frontotemporal dementia (FTD) is characterized by neuronal loss in the frontal and temporal lobes of the brain. Here, we provide the first evidence of striking morphological alterations in dentate granule cells (DGCs) of FTD patients and in a mouse model of the disease, Tau VLW mice. Taking advantage of the fact that the hippocampal dentate gyrus (DG) gives rise to newborn DGCs throughout the lifetime in rodents, we used RGB retroviruses to study the temporary course of these alterations in newborn DGCs of female Tau VLW mice. In addition, retroviruses that encode either PSD95:GFP or Syn:GFP revealed striking alterations in the afferent and efferent connectivity of newborn Tau VLW DGCs, and monosynaptic retrograde rabies virus tracing showed that these cells are disconnected from distal brain regions and local sources of excitatory innervation. However, the same cells exhibited a predominance of local inhibitory innervation. Accordingly, the expression of presynaptic and postsynaptic markers of inhibitory synapses was markedly increased in the DG of Tau VLW mice and FTD patients. Moreover, an increased number of neuropeptide Y-positive interneurons in the DG correlated with a reduced number of activated egr-1 + DGCs in Tau VLW mice. Finally, we tested the therapeutic potential of environmental enrichment and chemoactivation to reverse these alterations in mice. Both strategies reversed the morphological alterations of newborn DGCs and partially restored their connectivity in a mouse model of the disease. Moreover, our data point to remarkable morphological similarities between the DGCs of Tau VLW mice and FTD patients.Fil: Terreros Roncal, Julia. Universidad Autónoma de Madrid. Facultad de Ciencias; EspañaFil: Flor García, Miguel. Universidad Autónoma de Madrid. Facultad de Ciencias; EspañaFil: Moreno Jiménez, Elena P.. Universidad Autónoma de Madrid. Facultad de Ciencias; EspañaFil: Pallas Bazarra, Noemí. Universidad Autónoma de Madrid. Facultad de Ciencias; EspañaFil: Rábano, Alberto. No especifíca;Fil: Sah, Nirnath. National Institutes of Health; Estados UnidosFil: Van Praag, Henriette. National Institutes of Health; Estados UnidosFil: Giacomini, Damiana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Schinder, Alejandro Fabián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Ávila, Jesús. Universidad Autónoma de Madrid. Facultad de Ciencias; EspañaFil: Llorens Martín, Maria. Universidad Autónoma de Madrid. Facultad de Ciencias; Españ

Ancient Migratory Events in the Middle East: New Clues from the Y-Chromosome Variation of Modern Iranians

Knowledge of high resolution Y-chromosome haplogroup diversification within Iran provides important geographic context regarding the spread and compartmentalization of male lineages in the Middle East and southwestern Asia. At present, the Iranian population is characterized by an extraordinary mix of different ethnic groups speaking a variety of Indo-Iranian, Semitic and Turkic languages. Despite these features, only few studies have investigated the multiethnic components of the Iranian gene pool. In this survey 938 Iranian male DNAs belonging to 15 ethnic groups from 14 Iranian provinces were analyzed for 84 Y-chromosome biallelic markers and 10 STRs. The results show an autochthonous but non-homogeneous ancient background mainly composed by J2a sub-clades with different external contributions. The phylogeography of the main haplogroups allowed identifying post-glacial and Neolithic expansions toward western Eurasia but also recent movements towards the Iranian region from western Eurasia (R1b-L23), Central Asia (Q-M25), Asia Minor (J2a-M92) and southern Mesopotamia (J1-Page08). In spite of the presence of important geographic barriers (Zagros and Alborz mountain ranges, and the Dasht-e Kavir and Dash-e Lut deserts) which may have limited gene flow, AMOVA analysis revealed that language, in addition to geography, has played an important role in shaping the nowadays Iranian gene pool. Overall, this study provides a portrait of the Y-chromosomal variation in Iran, useful for depicting a more comprehensive history of the peoples of this area as well as for reconstructing ancient migration routes. In addition, our results evidence the important role of the Iranian plateau as source and recipient of gene flow between culturally and genetically distinct population