90 research outputs found
Synthesis of highly stable metal-containing extra-large-pore molecular sieves
[EN] The isomorphic substitution of two different metals (Mg and Co) within the framework of the ITQ-51 zeotype (IFO structure) using bulky aromatic proton sponges as organic structure-directing agents (OSDAs) has allowed the synthesis of different stable metal-containing extra-large-pore zeotypes with high pore accessibility and acidity. These metal-containing extra-large-pore zeolites, named MgITQ-51 and CoITQ-51, have been characterized by different techniques, such as powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectrometry, UV-Vis spectroscopy, temperature programmed desorption of ammonia and Fourier transform infrared spectroscopy, to study their physico-chemical properties. The characterization confirms the preferential insertion of Mg and Co atoms within the crystalline structure of the ITQ-51 zeotype, providing high Bronsted acidity, and allowing their use as efficient heterogeneous acid catalysts in industrially relevant reactions involving bulky organic molecules.Financial support by the Spanish Government-MINECO through 'Severo Ochoa' (SEV 2012-0267), Consolider Ingenio 2010-Multicat and MAT2012-37160 is acknowledged. The European Union is also acknowledged by the SynCatMatch project (ERC-AdG-2014-671093).Martínez Franco, R.; Paris-Carrizo, CG.; Moliner Marin, M.; Corma Canós, A. (2016). Synthesis of highly stable metal-containing extra-large-pore molecular sieves. Philosophical Transactions A: Mathematical, Physical and Engineering Sciences. 374(2061). https://doi.org/10.1098/rsta.2015.0075S3742061Jiang, J., Yu, J., & Corma, A. (2010). Extra-Large-Pore Zeolites: Bridging the Gap between Micro and Mesoporous Structures. Angewandte Chemie International Edition, 49(18), 3120-3145. doi:10.1002/anie.200904016Moliner, M., Rey, F., & Corma, A. (2013). Towards the Rational Design of Efficient Organic Structure-Directing Agents for Zeolite Synthesis. Angewandte Chemie International Edition, 52(52), 13880-13889. doi:10.1002/anie.201304713Davis, M. E. (1997). The Quest For Extra-Large Pore, Crystalline Molecular Sieves. Chemistry - A European Journal, 3(11), 1745-1750. doi:10.1002/chem.19970031104Davis, M. E. (2002). Ordered porous materials for emerging applications. Nature, 417(6891), 813-821. doi:10.1038/nature00785Corma, A. (2003). State of the art and future challenges of zeolites as catalysts. Journal of Catalysis, 216(1-2), 298-312. doi:10.1016/s0021-9517(02)00132-xCorma, A., Díaz-Cabañas, M. J., Jordá, J. L., Martínez, C., & Moliner, M. (2006). High-throughput synthesis and catalytic properties of a molecular sieve with 18- and 10-member rings. Nature, 443(7113), 842-845. doi:10.1038/nature05238Davis, M. E., Saldarriaga, C., Montes, C., Garces, J., & Crowdert, C. (1988). A molecular sieve with eighteen-membered rings. Nature, 331(6158), 698-699. doi:10.1038/331698a0Corma, A., & Davis, M. E. (2004). Issues in the Synthesis of Crystalline Molecular Sieves: Towards the Crystallization of Low Framework-Density Structures. ChemPhysChem, 5(3), 304-313. doi:10.1002/cphc.200300997Martinez-Franco, R., Moliner, M., Yun, Y., Sun, J., Wan, W., Zou, X., & Corma, A. (2013). Synthesis of an extra-large molecular sieve using proton sponges as organic structure-directing agents. Proceedings of the National Academy of Sciences, 110(10), 3749-3754. doi:10.1073/pnas.1220733110Staab, H. A., & Saupe, T. (1988). ?Proton Sponges? and the Geometry of Hydrogen Bonds: Aromatic Nitrogen Bases with Exceptional Basicities. Angewandte Chemie International Edition in English, 27(7), 865-879. doi:10.1002/anie.198808653Corma, A., Diaz-Cabanas, M. J., Jiang, J., Afeworki, M., Dorset, D. L., Soled, S. L., & Strohmaier, K. G. (2010). Extra-large pore zeolite (ITQ-40) with the lowest framework density containing double four- and double three-rings. Proceedings of the National Academy of Sciences, 107(32), 13997-14002. doi:10.1073/pnas.1003009107(s. f.). doi:10.1021/jp027447Martínez-Franco, R., Sun, J., Sastre, G., Yun, Y., Zou, X., Moliner, M., & Corma, A. (2014). Supra-molecular assembly of aromatic proton sponges to direct the crystallization of extra-large-pore zeotypes. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 470(2166), 20140107. doi:10.1098/rspa.2014.0107Man, P. P., Briend, M., Peltre, M. J., Lamy, A., Beaunier, P., & Barthomeuf, D. (1991). A topological model for the silicon incorporation in SAPO-37 molecular sieves: Correlations with acidity and catalysis. Zeolites, 11(6), 563-572. doi:10.1016/s0144-2449(05)80006-5Wilson ST Flanigen EM. 1986 Crystalline metal aluminophosphates . U.S. Patent 4 567 029.Corà, F., Saadoune, I., & Catlow, C. R. A. (2002). Lewis Acidity in Transition-Metal-Doped Microporous Aluminophosphates. Angewandte Chemie International Edition, 41(24), 4677-4680. doi:10.1002/anie.200290013Hartmann, M., & Kevan, L. (2002). Substitution of transition metal ions into aluminophosphates and silicoaluminophosphates: characterization and relation to catalysis. Research on Chemical Intermediates, 28(7-9), 625-695. doi:10.1163/15685670260469357Šponer, J., Čejka, J., Dědeček, J., & Wichterlová, B. (2000). Coordination and properties of cobalt in the molecular sieves CoAPO-5 and -11. Microporous and Mesoporous Materials, 37(1-2), 117-127. doi:10.1016/s1387-1811(99)00258-9Singh, P. S., Shaikh, R. A., Bandyopadhyay, R., & Rao, B. S. (1995). Synthesis of CoVPI-5 with bifunctional catalytic activity. Journal of the Chemical Society, Chemical Communications, (22), 2255. doi:10.1039/c39950002255Jhung, S. H., Jin, T., Kim, Y. H., & Chang, J.-S. (2008). Phase-selective crystallization of cobalt-incorporated aluminophosphate molecular sieves with large pore by microwave irradiation. Microporous and Mesoporous Materials, 109(1-3), 58-65. doi:10.1016/j.micromeso.2007.04.031Iton, L. E., Choi, I., Desjardins, J. A., & Maroni, V. A. (1989). Stabilization of Co (III) in aluminophosphate molecular sieve frameworks. Zeolites, 9(6), 535-538. doi:10.1016/0144-2449(89)90051-1Frache, A., Gianotti, E., & Marchese, L. (2003). Spectroscopic characterisation of microporous aluminophosphate materials with potential application in environmental catalysis. Catalysis Today, 77(4), 371-384. doi:10.1016/s0920-5861(02)00381-4Yu, T., Wang, J., Shen, M., & Li, W. (2013). NH3-SCR over Cu/SAPO-34 catalysts with various acid contents and low Cu loading. Catalysis Science & Technology, 3(12), 3234. doi:10.1039/c3cy00453hYang, X., Ma, H., Xu, Z., Xu, Y., Tian, Z., & Lin, L. (2007). Hydroisomerization of n-dodecane over Pt/MeAPO-11 (Me=Mg, Mn, Co or Zn) catalysts. Catalysis Communications, 8(8), 1232-1238. doi:10.1016/j.catcom.2006.11.00
Direct synthesis of the aluminosilicate form of the small pore CDO zeolite with novel OSDAs and the expanded polymorphs
[EN] A general procedure to synthesize the Al-containing layered CDO precursor (PreCDO) is presented, allowing its preparation under broad Si/Al molar ratios by using novel pyrrole-derived organic molecules as organic structure directing agents (OSDAs). The direct calcination of the PreCDO materials results in crystalline Al-containing small-pore CDO zeolites with controlled Al species in tetrahedral coordination. In contrast, mild acid treatments on the PreCDO materials allow achieving medium-pore interlayer expanded CDO zeolites (IEZ-CDO). These expanded zeolites show high crystallinity, high porosity and controlled Si/Al molar ratios. Finally, preliminary catalytic results indicate that the Al-containing CDO and IEZ-CDO samples show good activity and selectivity for the selective catalytic reduction (SCR) of NOx, and methanol-to-olefins (MTO) processes, respectively. (C) 2017 Elsevier Inc. All rights reserved.This work has been supported by the Spanish Government-MINECO through "Severo Ochoa" (SEV 2012-0267) and MAT2015-71261-R programs, and by the Fundacion Ramon Areces through a research project in "Life and Materials Sciences" program. The authors thank Isabel Millet for technical support.Martínez Franco, R.; Paris, C.; Martínez-Triguero, J.; Moliner Marin, M.; Corma Canós, A. (2017). Direct synthesis of the aluminosilicate form of the small pore CDO zeolite with novel OSDAs and the expanded polymorphs. Microporous and Mesoporous Materials. 246:147-157. https://doi.org/10.1016/j.micromeso.2017.03.014S14715724
Comprehensive characterization of neuroblastoma cell line subtypes reveals bilineage potential similar to neural crest stem cells
<p>Abstract</p> <p>Background</p> <p>Neuroblastic tumors (NBT) derive from neural crest stem cells (NCSC). Histologically, NBT are composed by neuroblasts and Schwannian cells. In culture, neuroblastic (N-), substrate-adherent (S-) and intermediate phenotype (I-) cell subtypes arise spontaneously.</p> <p>Methods</p> <p>Here, neuroblastoma (NB) cell line subtypes were characterized according to embryonic peripheral nervous system development markers (GAP43, Phox2b, Sox10, c-kit, GD2, NF68, vimentin, S100β, calcyclin and ABCG2), morphological features, gene expression and differentiation potential. I-type cells were investigated as a bipotential (neuronal and glial) differentiation stage.</p> <p>Results</p> <p>Positive immunostaining of NCSC (GAP43, c-kit, NF68, vimentin and Phox2b) and undifferentiated cell (ABCG2) markers was observed in all NB subtypes. N- and I-type cells displayed cytoplasmic membrane GD2 staining, while nuclear calcyclin was restricted to S-type. N- and I-type cells showed similar phenotype and immunoreactivity pattern. Differential gene expression was associated with each cell subtype. N- and I-type cells displayed similar differentiation capacity towards neuronal and glial lineage fates. S-type cells, upon induction, did not show a neuronal-like phenotype, despite gene expression changes.</p> <p>Conclusion</p> <p>Results suggest that N- and I-type NB cell subtypes represent an immature bilineage stage, able to progress towards neuronal and glial fates upon induction of differentiation. S-type cells appear irreversibly committed to a glial lineage fate.</p
Efficient Oligomerization of Pentene into Liquid Fuels on Nanocrystalline Beta Zeolites
[EN] Light alkenes oligomerization, performed in the presence of heterogeneous acid catalysts, is an interesting alternative for the production of clean liquid fuels. The process, when catalyzed by zeolites, is flexible and can be directed to the formation of oligomers in the gasoline, jet fuel, or diesel range by adjusting the reaction conditions and the zeolite's structure. Herein we show how reducing the crystal size of large-pore Beta zeolites down to 10-15 nm and controlling the number and strength distribution of their Bronsted acid sites leads to highly active and stable catalysts, selective to true oligomers within the naphtha and, especially, the diesel range. The shorter diffusion path lengths in the smaller crystallites and the reduced Bronsted acid site density of the two nanosized beta zeolites (10-15 nm) synthesized with Si/Al = 15 lead to 1-pentene conversion above 80% during the 6 h time on stream (TOS) at a space time (W/F) of 2.8 g.h.mol(-1). This value is higher than the olefin conversion obtained for a commercial nanobeta (30 nm) at a 3-fold space time of 9.1 g.h.mol(-1).Financial support by the Spanish Government-MINECO through "Severn Ochoa" (SEV-2016-0683), MAT2015-71261-R and CTQ2015-70126-R, by the Fundacion Ramon Areces through a research project within the "Life and Materials Sciences" program, and by the European Union through ERC-AdG-2014-671093-Syn-CatMatch is acknowledged. M.R.D-R. acknowledges "La Caixa-Severo Ochoa" International PhD Fellowships (call 2015). The Electron Microscopy Service of the Universitat Politecnica de Valencia is acknowledged for their help in sample characterization.Díaz-Rey, MDR.; Paris-Carrizo, CG.; Martínez Franco, R.; Moliner Marin, M.; Martínez, C.; Corma Canós, A. (2017). Efficient Oligomerization of Pentene into Liquid Fuels on Nanocrystalline Beta Zeolites. ACS Catalysis. 7(9):6170-6178. https://doi.org/10.1021/acscatal.7b00817S617061787
High TGFβ-Smad Activity Confers Poor Prognosis in Glioma Patients and Promotes Cell Proliferation Depending on the Methylation of the PDGF-B Gene
SummaryTGFβ acts as a tumor suppressor in normal epithelial cells and early-stage tumors and becomes an oncogenic factor in advanced tumors. The molecular mechanisms involved in the malignant function of TGFβ are not fully elucidated. We demonstrate that high TGFβ-Smad activity is present in aggressive, highly proliferative gliomas and confers poor prognosis in patients with glioma. We discern the mechanisms and molecular determinants of the TGFβ oncogenic response with a transcriptomic approach and by analyzing primary cultured patient-derived gliomas and human glioma biopsies. The TGFβ-Smad pathway promotes proliferation through the induction of PDGF-B in gliomas with an unmethylated PDGF-B gene. The epigenetic regulation of the PDGF-B gene dictates whether TGFβ acts as an oncogenic factor inducing PDGF-B and proliferation in human glioma
Influence of pore size in protein G'-grafted mesoporous silica nanoparticles as a serum pretreatment system for in vitro allergy diagnosis
Particles with the capacity to bind to immunoglobulin G (IgG) can be used for the purification of IgG or to process clinical samples for diagnostic purposes. For in vitro allergy diagnosis, the high IgG levels in serum can interfere with the detection of allergen-specific IgE, the main diagnostic biomarker. Although commercially available, current materials present a low IgG capture capacity at large IgG concentrations or require complex protocols, preventing their use in the clinic. In this work, mesoporous silica nanoparticles are prepared with different pore sizes, to which IgG-binding protein G’ is grafted. It is found that for one particular optimal pore size, the IgG capture capacity of the material is greatly enhanced. The capacity of this material to efficiently capture human IgG in a selective way (compared to IgE) is demonstrated in both solutions of known IgG concentrations as well as in complex samples, like serum, from healthy controls and allergic patients using a simple and fast incubation protocol. Interestingly, IgG removal using the best-performing material enhances in vitro IgE detection in sera from patients allergic to amoxicillin. These results highlight the great translation potential of this strategy to the clinic in the context of in vitro allergy diagnosis.Funding for Open Access charge: Universidad de Málaga/CBUA. TEM experiments
were performed in the ICTS “NANBIOSIS,” more specifically in the U28
Unit at IBIMA Plataforma BIONAND
Identification of novel targets in adipose tissue involved in non-alcoholic fatty liver disease progression
Obesity is a major risk factor for the development of Nonalcoholic fatty liver disease (NAFLD). We hypothesize that a dysfunctional subcutaneous white adipose tissue (scWAT) may lead to an accumulation of ectopic fat in the liver. Our aim was to investigate the molecular mechanisms involved in the causative role of scWAT in NALFD progression. We performed a RNA-sequencing analysis in a discovery cohort (n = 45) to identify genes in scWAT correlated with fatty liver index, a qualitative marker of liver steatosis. We then validated those targets in a second cohort (n = 47) of obese patients who had liver biopsies available. Finally, we obtained scWAT mesenchymal stem cells (MSCs) from 13 obese patients at different stages of NAFLD and established in vitro models of human MSC (hMSC)-derived adipocytes. We observed impaired adipogenesis in hMSC-derived adipocytes as liver steatosis increased, suggesting that an impaired adipogenic capacity is a critical event in the development of NAFLD. Four genes showed a differential expression pattern in both scWAT and hMSC-derived adipocytes, where their expression paralleled steatosis degree: SOCS3, DUSP1, SIK1, and GADD45B. We propose these genes as key players in NAFLD progression. They could eventually constitute potential new targets for future therapies against liver steatosis
The first genetic landscape of inherited retinal dystrophies in Portuguese patients identifies recurrent homozygous mutations as a frequent cause of pathogenesis.
Inherited retinal diseases (IRDs) are a group of ocular conditions characterized by an elevated genetic and clinical heterogeneity. They are transmitted almost invariantly as monogenic traits. However, with more than 280 disease genes identified so far, association of clinical phenotypes with genotypes can be very challenging, and molecular diagnosis is essential for genetic counseling and correct management of the disease. In addition, the prevalence and the assortment of IRD mutations are often population-specific. In this work, we examined 230 families from Portugal, with individuals suffering from a variety of IRD diagnostic classes (270 subjects in total). Overall, we identified 157 unique mutations (34 previously unreported) in 57 distinct genes, with a diagnostic rate of 76%. The IRD mutational landscape was, to some extent, different from those reported in other European populations, including Spanish cohorts. For instance, the EYS gene appeared to be the most frequently mutated, with a prevalence of 10% among all IRD cases. This was, in part, due to the presence of a recurrent and seemingly founder mutation involving the deletion of exons 13 and 14 of this gene. Moreover, our analysis highlighted that as many as 51% of our cases had mutations in a homozygous state. To our knowledge, this is the first study assessing a cross-sectional genotype-phenotype landscape of IRDs in Portugal. Our data reveal a rather unique distribution of mutations, possibly shaped by a small number of rare ancestral events that have now become prevalent alleles in patients
MicroRNA-200, associated with metastatic breast cancer, promotes traits of mammary luminal progenitor cells
MicroRNAs are critical regulators of gene networks in normal and abnormal biological processes. Focusing on invasive ductal breast cancer (IDC), we have found dysregulated expression in tumor samples of several microRNAs, including the miR-200 family, along progression from primary tumors to distant metastases, further reflected in higher blood levels of miR-200b and miR-7 in IDC patients with regional or distant metastases relative to patients with primary node-negative tumors. Forced expression of miR-200s in MCF10CA1h mammary cells induced an enhanced epithelial program, aldehyde dehydrogenase (ALDH) activity, mammosphere growth and ability to form branched tubuloalveolar structures while promoting orthotopic tumor growth and lung colonization in vivo. MiR-200s also induced the constitutive activation of the PI3K-Akt signaling through downregulation of PTEN, and the enhanced mammosphere growth and ALDH activity induced in MCF10CA1h cells by miR-200s required the activation of this signaling pathway. Interestingly, the morphology of tumors formed in vivo by cells expressing miR-200s was reminiscent of metaplastic breast cancer (MBC). Indeed, the epithelial components of MBC samples expressed significantly higher levels of miR-200s than their mesenchymal components and displayed a marker profile compatible with luminal progenitor cells. We propose that microRNAs of the miR-200 family promote traits of highly proliferative breast luminal progenitor cells, thereby exacerbating the growth and metastatic properties of transformed mammary epithelial cells
Hábitat urbano : estudio y diseño de parámetros e indicadores como instrumentos para medir, evaluar y proponer calidad de vida en el espacio público para la interacción social
La finalidad de esta investigación es aportar premisas para el diseño y la recualificación del espacio público particularmente en áreas centrales de nuestras ciudades. El concepto de recualificación hace referencia a dotar de nuevas cualidades a sectores que las han perdido o que nunca las tuvieron, trabajando con las preexistencias como herramientas de diseño. La orientación de estas cualidades es direccionada a obtener mayor calidad de vida. Buscaremos identificar y cuantificar factores que aportan calidad de vida en el espacio público. Estos indicadores nos permitirán identificar la realidad urbana, para poder utilizarlos como instrumentos de medición y/o diseño que mejoren la calidad de vida en el espacio público de manera continua y sostenida. Estas mediciones se observarán y procesarán científicamente en el ámbito de un modelo de observatorio urbano, en un contexto de tiempo y espacio determinado. Buscaremos establecer los valores mínimos admisibles y óptimos, para luego diseñar protocolos proyectuales. La investigación se estructurará en 3 etapas: La primera, estudio y análisis exhaustivo de casos paradigmáticos en el ámbito nacional e internacional para la conformación de la plataforma teórica de trabajo. La segunda, tomando como caso de estudio un sector en particular de la ciudad, será vista desde dos miradas, la actual sumada a una futura de carácter propositivo. La tercera, de síntesis permitirá establecer pautas para la elaboración de lineamientos que aporten calidad de vida en el espacio público para ser aplicados para la recualificación de la ciudad o sectores de la misma. Elaboración de protocolos.Fil: Paris, Ángel Omar. Universidad Católica de Córdoba. Facultad de Arquitectura; ArgentinaFil: Martín Schmädke, José Augusto. Universidad Católica de Córdoba. Facultad de Arquitectura; Argentin
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