1,385 research outputs found
Sobre la presencia de Powellita, Mo O4 Ca, en Gualba de Dalt (Barcelona)
Se cita por primera vez la powellita, Mo O, Ca, en Catalunya (Gualba de Dalt, Barcelona). Los ejemplares recolectados se estudiaron mediante las técnicas siguientes: analisis quimico, picnometria, difractometria y espectrografia por fluorescencia de rayos X. Se consideran las posibles relaciones entre la powellita y la molibdenita, S, Mo, presente en el mismo yacimiento
Sobre la presencia de Powellita, Mo O4 Ca, en Gualba de Dalt (Barcelona)
Se cita por primera vez la powellita, Mo O, Ca, en Catalunya (Gualba de Dalt, Barcelona). Los ejemplares recolectados se estudiaron mediante las técnicas siguientes: analisis quimico, picnometria, difractometria y espectrografia por fluorescencia de rayos X. Se consideran las posibles relaciones entre la powellita y la molibdenita, S, Mo, presente en el mismo yacimiento
N-Doped graphene as a metal-free catalyst for glucose oxidation to succinic acid
[EN] N-Containing graphenes obtained either by simultaneous amination and reduction of graphene oxide or by pyrolysis of chitosan under an inert atmosphere have been found to act as catalysts for the selective wet oxidation of glucose to succinic acid. Selectivity values over 60% at complete glucose conversion have been achieved by performing the reaction at 160 degrees C and 18 atm O-2 pressure for 20 h. This activity has been attributed to graphenic-type N atoms on graphene. The active N-containing graphene catalysts were used four times without observing a decrease in conversion and selectivity of the process. A mechanism having tartaric and fumaric acids as key intermediates is proposed.Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa, Grapas and CTQ2015-69153-CO2-R1) and Generalitat Valenciana (Prometeo 2013-014) is gratefully acknowledged. Prof. Simona M. Coman kindly acknowledges UEFISCDI for financial support (project PN-II-PT-PCCA-2013-4-1090, Nr. 44/2014). Cristina Bucur acknowledges Core Programme, Project PN-480103/2016.Rizescu, C.; Podolean, I.; Albero-Sancho, J.; Parvulescu, VI.; Coman, SM.; Bucur, C.; Puche Panadero, M.... (2017). N-Doped graphene as a metal-free catalyst for glucose oxidation to succinic acid. Green Chemistry. 19(8):1999-2005. https://doi.org/10.1039/C7GC00473GS19992005198Alonso, D. M., Wettstein, S. G., & Dumesic, J. A. (2012). Bimetallic catalysts for upgrading of biomass to fuels and chemicals. Chemical Society Reviews, 41(24), 8075. doi:10.1039/c2cs35188aCherubini, F. (2010). The biorefinery concept: Using biomass instead of oil for producing energy and chemicals. Energy Conversion and Management, 51(7), 1412-1421. doi:10.1016/j.enconman.2010.01.015Christensen, C. H., Rass-Hansen, J., Marsden, C. C., Taarning, E., & Egeblad, K. (2008). The Renewable Chemicals Industry. ChemSusChem, 1(4), 283-289. doi:10.1002/cssc.200700168Lange, J.-P. (2007). Lignocellulose conversion: an introduction to chemistry, process and economics. Biofuels, Bioproducts and Biorefining, 1(1), 39-48. doi:10.1002/bbb.7Corma, A., Iborra, S., & Velty, A. (2007). Chemical Routes for the Transformation of Biomass into Chemicals. Chemical Reviews, 107(6), 2411-2502. doi:10.1021/cr050989dCliment, M. J., Corma, A., & Iborra, S. (2011). Converting carbohydrates to bulk chemicals and fine chemicals over heterogeneous catalysts. Green Chemistry, 13(3), 520. doi:10.1039/c0gc00639dBjerre, A. B., Olesen, A. B., Fernqvist, T., Plöger, A., & Schmidt, A. S. (2000). Pretreatment of wheat straw using combined wet oxidation and alkaline hydrolysis resulting in convertible cellulose and hemicellulose. Biotechnology and Bioengineering, 49(5), 568-577. doi:10.1002/(sici)1097-0290(19960305)49:53.0.co;2-6Klinke, H. B., Ahring, B. K., Schmidt, A. S., & Thomsen, A. B. (2002). Characterization of degradation products from alkaline wet oxidation of wheat straw. Bioresource Technology, 82(1), 15-26. doi:10.1016/s0960-8524(01)00152-3Schmidt, A. S., & Thomsen, A. B. (1998). Optimization of wet oxidation pretreatment of wheat straw. Bioresource Technology, 64(2), 139-151. doi:10.1016/s0960-8524(97)00164-8Gogate, P. R., & Pandit, A. B. (2004). A review of imperative technologies for wastewater treatment I: oxidation technologies at ambient conditions. Advances in Environmental Research, 8(3-4), 501-551. doi:10.1016/s1093-0191(03)00032-7Mishra, V. S., Mahajani, V. V., & Joshi, J. B. (1995). Wet Air Oxidation. Industrial & Engineering Chemistry Research, 34(1), 2-48. doi:10.1021/ie00040a001Zakzeski, J., Bruijnincx, P. C. A., Jongerius, A. L., & Weckhuysen, B. M. (2010). The Catalytic Valorization of Lignin for the Production of Renewable Chemicals. Chemical Reviews, 110(6), 3552-3599. doi:10.1021/cr900354uPodolean, I., Rizescu, C., Bala, C., Rotariu, L., Parvulescu, V. I., Coman, S. M., & Garcia, H. (2016). Unprecedented Catalytic Wet Oxidation of Glucose to Succinic Acid Induced by the Addition ofn-Butylamine to a RuIIICatalyst. ChemSusChem, 9(17), 2307-2311. doi:10.1002/cssc.201600474Huang, C., Li, C., & Shi, G. (2012). Graphene based catalysts. Energy & Environmental Science, 5(10), 8848. doi:10.1039/c2ee22238hNavalon, S., Dhakshinamoorthy, A., Alvaro, M., & Garcia, H. (2014). Carbocatalysis by Graphene-Based Materials. Chemical Reviews, 114(12), 6179-6212. doi:10.1021/cr4007347Su, D. S., Perathoner, S., & Centi, G. (2013). Nanocarbons for the Development of Advanced Catalysts. Chemical Reviews, 113(8), 5782-5816. doi:10.1021/cr300367dDhakshinamoorthy, A., Primo, A., Concepcion, P., Alvaro, M., & Garcia, H. (2013). Doped Graphene as a Metal-Free Carbocatalyst for the Selective Aerobic Oxidation of Benzylic Hydrocarbons, Cyclooctane and Styrene. Chemistry - A European Journal, 19(23), 7547-7554. doi:10.1002/chem.201300653Huang, H., Huang, J., Liu, Y.-M., He, H.-Y., Cao, Y., & Fan, K.-N. (2012). Graphite oxide as an efficient and durable metal-free catalyst for aerobic oxidative coupling of amines to imines. Green Chemistry, 14(4), 930. doi:10.1039/c2gc16681jLi, X.-H., Chen, J.-S., Wang, X., Sun, J., & Antonietti, M. (2011). Metal-Free Activation of Dioxygen by Graphene/g-C3N4Nanocomposites: Functional Dyads for Selective Oxidation of Saturated Hydrocarbons. Journal of the American Chemical Society, 133(21), 8074-8077. doi:10.1021/ja200997aSun, H., Wang, Y., Liu, S., Ge, L., Wang, L., Zhu, Z., & Wang, S. (2013). Facile synthesis of nitrogen doped reduced graphene oxide as a superior metal-free catalyst for oxidation. Chemical Communications, 49(85), 9914. doi:10.1039/c3cc43401jYang, J.-H., Sun, G., Gao, Y., Zhao, H., Tang, P., Tan, J., … Ma, D. (2013). Direct catalytic oxidation of benzene to phenol over metal-free graphene-based catalyst. Energy & Environmental Science, 6(3), 793. doi:10.1039/c3ee23623dRocha, R. P., Gonçalves, A. G., Pastrana-Martínez, L. M., Bordoni, B. C., Soares, O. S. G. P., Órfão, J. J. M., … Pereira, M. F. R. (2015). Nitrogen-doped graphene-based materials for advanced oxidation processes. Catalysis Today, 249, 192-198. doi:10.1016/j.cattod.2014.10.046Wang, Y., Xie, Y., Sun, H., Xiao, J., Cao, H., & Wang, S. (2016). Efficient Catalytic Ozonation over Reduced Graphene Oxide for p-Hydroxylbenzoic Acid (PHBA) Destruction: Active Site and Mechanism. ACS Applied Materials & Interfaces, 8(15), 9710-9720. doi:10.1021/acsami.6b01175Duan, X., Su, C., Zhou, L., Sun, H., Suvorova, A., Odedairo, T., … Wang, S. (2016). Surface controlled generation of reactive radicals from persulfate by carbocatalysis on nanodiamonds. Applied Catalysis B: Environmental, 194, 7-15. doi:10.1016/j.apcatb.2016.04.043Kang, J., Duan, X., Zhou, L., Sun, H., Tadé, M. O., & Wang, S. (2016). Carbocatalytic activation of persulfate for removal of antibiotics in water solutions. Chemical Engineering Journal, 288, 399-405. doi:10.1016/j.cej.2015.12.040Sun, H., Kwan, C., Suvorova, A., Ang, H. M., Tadé, M. O., & Wang, S. (2014). Catalytic oxidation of organic pollutants on pristine and surface nitrogen-modified carbon nanotubes with sulfate radicals. Applied Catalysis B: Environmental, 154-155, 134-141. doi:10.1016/j.apcatb.2014.02.012Wang, X., Qin, Y., Zhu, L., & Tang, H. (2015). Nitrogen-Doped Reduced Graphene Oxide as a Bifunctional Material for Removing Bisphenols: Synergistic Effect between Adsorption and Catalysis. Environmental Science & Technology, 49(11), 6855-6864. doi:10.1021/acs.est.5b01059Lai, L., Potts, J. R., Zhan, D., Wang, L., Poh, C. K., Tang, C., … Ruoff, R. S. (2012). Exploration of the active center structure of nitrogen-doped graphene-based catalysts for oxygen reduction reaction. Energy & Environmental Science, 5(7), 7936. doi:10.1039/c2ee21802jLi, X., Wang, H., Robinson, J. T., Sanchez, H., Diankov, G., & Dai, H. (2009). Simultaneous Nitrogen Doping and Reduction of Graphene Oxide. Journal of the American Chemical Society, 131(43), 15939-15944. doi:10.1021/ja907098fLong, D., Li, W., Ling, L., Miyawaki, J., Mochida, I., & Yoon, S.-H. (2010). Preparation of Nitrogen-Doped Graphene Sheets by a Combined Chemical and Hydrothermal Reduction of Graphene Oxide. Langmuir, 26(20), 16096-16102. doi:10.1021/la102425aLavorato, C., Primo, A., Molinari, R., & Garcia, H. (2013). N-Doped Graphene Derived from Biomass as a Visible-Light Photocatalyst for Hydrogen Generation from Water/Methanol Mixtures. Chemistry - A European Journal, 20(1), 187-194. doi:10.1002/chem.201303689Primo, A., Atienzar, P., Sanchez, E., Delgado, J. M., & García, H. (2012). From biomass wastes to large-area, high-quality, N-doped graphene: catalyst-free carbonization of chitosan coatings on arbitrary substrates. Chemical Communications, 48(74), 9254. doi:10.1039/c2cc34978gPrimo, A., Sánchez, E., Delgado, J. M., & García, H. (2014). High-yield production of N-doped graphitic platelets by aqueous exfoliation of pyrolyzed chitosan. Carbon, 68, 777-783. doi:10.1016/j.carbon.2013.11.068Chan, L. H., Hong, K. H., Xiao, D. Q., Lin, T. C., Lai, S. H., Hsieh, W. J., & Shih, H. C. (2004). Resolution of the binding configuration in nitrogen-doped carbon nanotubes. Physical Review B, 70(12). doi:10.1103/physrevb.70.125408Guo, B., Liu, Q., Chen, E., Zhu, H., Fang, L., & Gong, J. R. (2010). Controllable N-Doping of Graphene. Nano Letters, 10(12), 4975-4980. doi:10.1021/nl103079jSun, L., Wang, L., Tian, C., Tan, T., Xie, Y., Shi, K., … Fu, H. (2012). Nitrogen-doped graphene with high nitrogen level via a one-step hydrothermal reaction of graphene oxide with urea for superior capacitive energy storage. RSC Advances, 2(10), 4498. doi:10.1039/c2ra01367cAsedegbega-Nieto, E., Perez-Cadenas, M., Morales, M. V., Bachiller-Baeza, B., Gallegos-Suarez, E., Rodriguez-Ramos, I., & Guerrero-Ruiz, A. (2014). High nitrogen doped graphenes and their applicability as basic catalysts. Diamond and Related Materials, 44, 26-32. doi:10.1016/j.diamond.2014.01.019Jiang, H., Yu, X., Nie, R., Lu, X., Zhou, D., & Xia, Q. (2016). Selective hydrogenation of aromatic carboxylic acids over basic N-doped mesoporous carbon supported palladium catalysts. Applied Catalysis A: General, 520, 73-81. doi:10.1016/j.apcata.2016.04.009Primo, A., Parvulescu, V., & Garcia, H. (2016). Graphenes as Metal-Free Catalysts with Engineered Active Sites. The Journal of Physical Chemistry Letters, 8(1), 264-278. doi:10.1021/acs.jpclett.6b0199
Estudio de la reacción entre el Hg(l) y el ácido etilenglicol bis (β-amino etil éter) tetraacético. Determinación espectrofotométrica de Hg22+
The reaction between Hg(I) and ethyleneglycol bis (β-aminoethylether)- N, N, N3, N3 tetraacetate (EGTA) in a weakly acidic médium (pH ≈ 5) is studied by U. V. spectrophotometric techniques. The maxiraum of absorption which appears at 247 nm is supposed due to the formation of a Hg(I) - EGTA complex. This compotmd is unstable and it decomposes slowly with formation of Hg(II) chelate and metallic mercury. When the absorbance is measured at fixed time (5 minutes), it is fovmd that Beer's law is obeyed from 1 up to 30 p p m of Hg(I) at 247 nm
Analysis of the safety culture in a Cardiology Unit managed by processes
La cultura sobre seguridad se perfila como uno de los requisitos para evitar la aparición de efectos adversos, sin embargo no se ha estudiado en el ámbito de la cardiología. El objetivo es evaluar la cultura de seguridad en una unidad de cardiología que tiene implantado y certificado un sistema integrado de gestión de calidad y riesgos para la seguridad del paciente. Método: Se realizó un estudio observacional trasversal en 2 años consecutivos utilizando la encuesta Hospital Survey on Patient Safety Culture de la «Agency for Healthcare Research and Quality» en su versión española (42 ítems agrupados en 12 dimensiones) sobre todo el personal. Se comparó el porcentaje de respuestas positivas de cada dimensión en 2014 y 2015, así como con los datos a nivel nacional y en EE. UU., siguiendo las recomendaciones establecidas. Resultados: La valoración global, sobre un máximo de 5, fue de 4.5 en 2014 y de 4.7 en 2015. Identificamos 7 dimensiones como fortaleza. Las peor valoradas fueron: Dotación de personal, Apoyo de la gerencia y Trabajo en equipo entre unidades. La comparación mostró superioridad en todas las dimensiones a nivel nacional, y en 8 respecto a los datos del registro americano. Conclusiones: La cultura de seguridad en una unidad de cardiología con un sistema integrado de gestión de calidad y riesgos y seguridad del paciente es elevada, superior a la nacional en todas sus dimensiones y en la mayoría de ellas respecto al registro de EE. UU.The safety culture is one of the requirements to prevent the occurrence of adverse effects, however has not been studied in the field of cardiology. The objective is to evaluate the safety culture in a cardiology unit has implemented and certified an integrated quality and risk management for patient safety system. Methods: A transversal observational study was made in 2 consecutive years using the survey “Hospital Survey on Patient Safety Culture” of the “Agency for Healthcare Research and Quality” in its Spanish version (42 items grouped into 12 dimensions) in all staff. The percentage of positive responses in each dimension in 2014 and 2015 were compared, as well as national data and United States data, following the established rules. Results: The overall assessment of a possible 5, was 4.5 in 2014 and 4.7 in 2015. We identified seven dimensions as a fortress. The worst rated were: staffing, management support and teamwork between units. The comparison showed superiority in all dimensions respect to national data, and 8 respect to American data. Conclusions: The safety culture in a Cardiology Unit with an integrated quality and risk management and patient safety system is high, higher than the national in all its dimensions and in most of them respect to the United States
Methodological approaches to determining the marine radiocarbon reservoir effect
The marine radiocarbon reservoir effect is an offset in 14C age between contemporaneous organisms from the terrestrial environment and organisms that derive their carbon from the marine environment. Quantification of this effect is of crucial importance for correct calibration of the <sup>14</sup>C ages of marine-influenced samples to the calendrical timescale. This is fundamental to the construction of archaeological and palaeoenvironmental chronologies when such samples are employed in <sup>14</sup>C analysis. Quantitative measurements of temporal variations in regional marine reservoir ages also have the potential to be used as a measure of process changes within Earth surface systems, due to their link with climatic and oceanic changes. The various approaches to quantification of the marine radiocarbon reservoir effect are assessed, focusing particularly on the North Atlantic Ocean. Currently, the global average marine reservoir age of surface waters, R(t), is c. 400 radiocarbon years; however, regional values deviate from this as a function of climate and oceanic circulation systems. These local deviations from R(t) are expressed as +R values. Hence, polar waters exhibit greater reservoir ages (δR = c. +400 to +800 <sup>14</sup>C y) than equatorial waters (δR = c. 0 <sup>14</sup>C y). Observed temporal variations in δR appear to reflect climatic and oceanographic changes. We assess three approaches to quantification of marine reservoir effects using known age samples (from museum collections), tephra isochrones (present onshore/offshore) and paired marine/terrestrial samples (from the same context in, for example, archaeological sites). The strengths and limitations of these approaches are evaluated using examples from the North Atlantic region. It is proposed that, with a suitable protocol, accelerator mass spectrometry (AMS) measurements on paired, short-lived, single entity marine and terrestrial samples from archaeological deposits is the most promising approach to constraining changes over at least the last 5 ky BP
Bortezomib decreases Rb phosphorylation and induces caspase-dependent apoptosis in Imatinib-sensitive and -resistant Bcr-Abl1-expressing cells
The use of c-abl-specific inhibitors such as Imatinib (IM)
or Dasatinib has revolutionized the treatment of chronic
myeloid leukemia (CML). However, a significant percentage
of patients become resistant to IM. In this report, we
have analyzed the possibility of using the proteasome as a
molecular target in CML. Our results show that cells that
express Bcr-Abl1 are more sensitive to the inhibition of
the proteasome with Bortezomib (Btz) than control cells.
This treatment reduces the proliferation of Bcr-Abl1-
expressing cells, by inactivating NF-jB2 and decreasing
the phosphorylation of Rb, eventually leading to an
increase in caspase-dependent apoptosis. Furthermore,
we show that Btz also induces cell-cycle arrest and
apoptosis in cells expressing Bcr-Abl1 mutants that are
resistant to IM. These results unravel a new molecular
target of Btz, that is the Rb pathway, and open new
possibilities in the treatment of CML especially for
patients that become resistant to IM because of the
presence of the T315I mutation
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Search for lepton-flavour-violating decays of Higgs-like bosons.
A search is presented for a Higgs-like boson with mass in the range 45 to 195 GeV/c2 decaying into a muon and a tau lepton. The dataset consists of proton-proton interactions at a centre-of-mass energy of 8 TeV , collected by the LHCb experiment, corresponding to an integrated luminosity of 2 fb-1 . The tau leptons are reconstructed in both leptonic and hadronic decay channels. An upper limit on the production cross-section multiplied by the branching fraction at 95% confidence level is set and ranges from 22 pb for a boson mass of 45 GeV/c2 to 4 pb for a mass of 195 GeV/c2
Mercat de l'art, col·leccionisme i museus 2018
Recull de ponències presentades a la setena Jornada Mercat de l'Art, Col·leccionisme i Museus, celebrada el 26 d'octubre de 2018 al Saló d'Or del Palau Maricel de Sitges
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