219 research outputs found

    Metal solution precursors: their role during the synthesis of MoVTeNb mixed oxide catalysts

    Full text link
    [EN] Synthesized via the slurry method and activated at high temperature (873 K), MoVTeNb multimetallic mixed oxides are applied to catalyze the oxidative dehydrogenation of ethane to ethylene (ODHE). Mixed oxides typically contain M1 and M2 crystalline phases, the relative contribution of these phases and the respective catalytic behaviour being notably influenced by the preparation conditions of the metallic aqueous solution precursor, given the complexity of the chemical interactions of metal species in solution. Thus, detailed in situ UV-vis and Raman studies of the chemical species formed in solution during each step of the synthetic procedure are presented herein. The main role of vanadium is to form decavanadate ions, which interact with Mo species to generate an Anderson-type structure. When niobium oxalate solution is added into the MoVTe solution, a yellow-coloured gel is immediately formed due to a common ion effect. When liquid and gel phases are separated, the M1 crystalline phase is produced solely from the gel phase. Attention is also devoted to the influence and role of each metal cation (Mo, V, Te and Nb) on the formation of the active M1 crystalline phase and the catalytic behaviour in the ODHE. The catalyst constituted mostly of M1 crystalline phase is able to convert 45% of the fed ethane, with a selectivity to ethylene of around 90%.This work was financially supported by the Instituto Mexicano del Petroleo (IMP) Project D.61010. EMF thanks CONACyT Mexico and IMP. JMLN thanks DGICYT in Spain (Project CTQ2015-68951-C3-1-R).Sánchez-Valente, J.; Maya-Flores, E.; Armendariz-Herrera, H.; Quintana-Solorzano, R.; López Nieto, JM. (2018). Metal solution precursors: their role during the synthesis of MoVTeNb mixed oxide catalysts. Catalysis Science & Technology. 8(12):3123-3132. https://doi.org/10.1039/c8cy00750kS31233132812Ushikubo, T., Oshima, K., Kayou, A., Vaarkamp, M., & Hatano, M. (1997). Ammoxidation of Propane over Catalysts Comprising Mixed Oxides of Mo and V. Journal of Catalysis, 169(1), 394-396. doi:10.1006/jcat.1997.1692Ushikubo, T., Oshima, K., Kayou, A., & Hatano, M. (1997). Ammoxidation of propane over Mo-V-Nb-Te mixed oxide catalysts. Spillover and Migration of Surface Species on Catalysts, Proceedings of the 4th International Conference on Spillover, 473-480. doi:10.1016/s0167-2991(97)80871-3Ushikubo, T. (2000). Recent topics of research and development of catalysis by niobium and tantalum oxides. Catalysis Today, 57(3-4), 331-338. doi:10.1016/s0920-5861(99)00344-2Ueda, W., & Oshihara, K. (2000). Selective oxidation of light alkanes over hydrothermally synthesized Mo-V-M-O (M=Al, Ga, Bi, Sb, and Te) oxide catalysts. Applied Catalysis A: General, 200(1-2), 135-143. doi:10.1016/s0926-860x(00)00627-xWatanabe, H., & Koyasu, Y. (2000). New synthesis route for Mo–V–Nb–Te mixed oxides catalyst for propane ammoxidation. Applied Catalysis A: General, 194-195, 479-485. doi:10.1016/s0926-860x(99)00394-4Botella, P., Solsona, B., Martinez-Arias, A., & López Nieto, J. M. (2001). Catalysis Letters, 74(3/4), 149-154. doi:10.1023/a:1016614132694Oshihara, K., Hisano, T., & Ueda, W. (2001). Topics in Catalysis, 15(2/4), 153-160. doi:10.1023/a:1016630307377Botella, P., López Nieto, J. M., Solsona, B., Mifsud, A., & Márquez, F. (2002). The Preparation, Characterization, and Catalytic Behavior of MoVTeNbO Catalysts Prepared by Hydrothermal Synthesis. Journal of Catalysis, 209(2), 445-455. doi:10.1006/jcat.2002.3648Millet, J. M. M., Roussel, H., Pigamo, A., Dubois, J. L., & Jumas, J. C. (2002). Characterization of tellurium in MoVTeNbO catalysts for propane oxidation or ammoxidation. Applied Catalysis A: General, 232(1-2), 77-92. doi:10.1016/s0926-860x(02)00078-9DeSanto Jr., P., Buttrey, D. J., Grasselli, R. K., Lugmair, C. G., Volpe, A. F., Toby, B. H., & Vogt, T. (2003). Topics in Catalysis, 23(1/4), 23-38. doi:10.1023/a:1024812101856Millet, J. M. ., Baca, M., Pigamo, A., Vitry, D., Ueda, W., & Dubois, J. . (2003). Study of the valence state and coordination of antimony in MoVSbO catalysts determined by XANES and EXAFS. Applied Catalysis A: General, 244(2), 359-370. doi:10.1016/s0926-860x(02)00614-2BOTELLA, P. (2004). Selective oxidative dehydrogenation of ethane on MoVTeNbO mixed metal oxide catalysts. Journal of Catalysis, 225(2), 428-438. doi:10.1016/j.jcat.2004.04.024Holmberg, J., Grasselli, R. K., & Andersson, A. (2004). Catalytic behaviour of M1, M2, and M1/M2 physical mixtures of the Mo–V–Nb–Te–oxide system in propane and propene ammoxidation. Applied Catalysis A: General, 270(1-2), 121-134. doi:10.1016/j.apcata.2004.04.029Grasselli, R. K., Buttrey, D. J., DeSanto, P., Burrington, J. D., Lugmair, C. G., Volpe, A. F., & Weingand, T. (2004). Active centers in Mo–V–Nb–Te–O (amm)oxidation catalysts. Catalysis Today, 91-92, 251-258. doi:10.1016/j.cattod.2004.03.060Ueda, W., Vitry, D., & Katou, T. (2005). Crystalline MoVO based complex oxides as selective oxidation catalysts of propane. Catalysis Today, 99(1-2), 43-49. doi:10.1016/j.cattod.2004.09.022Murayama, H., Vitry, D., Ueda, W., Fuchs, G., Anne, M., & Dubois, J. L. (2007). Structure characterization of orthorhombic phase in MoVTeNbO catalyst by powder X-ray diffraction and XANES. Applied Catalysis A: General, 318, 137-142. doi:10.1016/j.apcata.2006.10.050Guliants, V. V., Bhandari, R., Swaminathan, B., Vasudevan, V. K., Brongersma, H. H., Knoester, A., … Han, S. (2005). Roles of Surface Te, Nb, and Sb Oxides in Propane Oxidation to Acrylic Acid over Bulk Orthorhombic Mo−V−O Phase. The Journal of Physical Chemistry B, 109(50), 24046-24055. doi:10.1021/jp054641yGrasselli, R. K., Buttrey, D. J., Burrington, J. D., Andersson, A., Holmberg, J., Ueda, W., … Volpe, A. F. (2006). Active centers, catalytic behavior, symbiosis and redox properties of MoV(Nb,Ta)TeO ammoxidation catalysts. Topics in Catalysis, 38(1-3), 7-16. doi:10.1007/s11244-006-0066-xSafonova, O. V., Deniau, B., & Millet, J.-M. M. (2006). Mechanism of the Oxidation−Reduction of the MoVSbNbO Catalyst:  In Operando X-ray Absorption Spectroscopy and Electrical Conductivity Measurements. The Journal of Physical Chemistry B, 110(47), 23962-23967. doi:10.1021/jp064347lWagner, J. B., Timpe, O., Hamid, F. A., Trunschke, A., Wild, U., Su, D. S., … Schlögl, R. (2006). Surface texturing of Mo–V–Te–Nb–O x selective oxidation catalysts. Topics in Catalysis, 38(1-3), 51-58. doi:10.1007/s11244-006-0070-1Kolen’ko, Y. V., Zhang, W., d’ Alnoncourt, R. N., Girgsdies, F., Hansen, T. W., Wolfram, T., … Trunschke, A. (2011). Synthesis of MoVTeNb Oxide Catalysts with Tunable Particle Dimensions. ChemCatChem, 3(10), 1597-1606. doi:10.1002/cctc.201100089Hävecker, M., Wrabetz, S., Kröhnert, J., Csepei, L.-I., Naumann d’Alnoncourt, R., Kolen’ko, Y. V., … Trunschke, A. (2012). Surface chemistry of phase-pure M1 MoVTeNb oxide during operation in selective oxidation of propane to acrylic acid. Journal of Catalysis, 285(1), 48-60. doi:10.1016/j.jcat.2011.09.012Ishikawa, S., Tashiro, M., Murayama, T., & Ueda, W. (2014). Seed-Assisted Synthesis of Crystalline Mo3VOx Oxides and Their Crystal Formation Mechanism. Crystal Growth & Design, 14(9), 4553-4561. doi:10.1021/cg500661pNieto, J. M. L., Botella, P., Vázquez, M. I., & Dejoz, A. (2002). The selective oxidative dehydrogenation of ethane over hydrothermally synthesised MoVTeNb catalysts. Chem. Commun., (17), 1906-1907. doi:10.1039/b204037aLópez Nieto, J. ., Botella, P., Concepción, P., Dejoz, A., & Vázquez, M. . (2004). Oxidative dehydrogenation of ethane on Te-containing MoVNbO catalysts. Catalysis Today, 91-92, 241-245. doi:10.1016/j.cattod.2004.03.040Ivars, F., Botella, P., Dejoz, A., Nieto, J. M. L., Concepción, P., & Vázquez, M. I. (2006). Selective oxidation of short-chain alkanes over hydrothermally prepared MoVTeNbO catalysts. Topics in Catalysis, 38(1-3), 59-67. doi:10.1007/s11244-006-0071-0Botella, P., Dejoz, A., Abello, M. C., Vázquez, M. I., Arrúa, L., & López Nieto, J. M. (2009). Selective oxidation of ethane: Developing an orthorhombic phase in Mo–V–X (X=Nb, Sb, Te) mixed oxides. Catalysis Today, 142(3-4), 272-277. doi:10.1016/j.cattod.2008.09.016Deniau, B., Millet, J. M. M., Loridant, S., Christin, N., & Dubois, J. L. (2008). Effect of several cationic substitutions in the M1 active phase of the MoVTeNbO catalysts used for the oxidation of propane to acrylic acid. Journal of Catalysis, 260(1), 30-36. doi:10.1016/j.jcat.2008.08.020SOLSONA, B., VAZQUEZ, M., IVARS, F., DEJOZ, A., CONCEPCION, P., & LOPEZNIETO, J. (2007). Selective oxidation of propane and ethane on diluted Mo–V–Nb–Te mixed-oxide catalysts. Journal of Catalysis, 252(2), 271-280. doi:10.1016/j.jcat.2007.09.019Nguyen, T. T., Burel, L., Nguyen, D. L., Pham-Huu, C., & Millet, J. M. M. (2012). Catalytic performance of MoVTeNbO catalyst supported on SiC foam in oxidative dehydrogenation of ethane and ammoxidation of propane. Applied Catalysis A: General, 433-434, 41-48. doi:10.1016/j.apcata.2012.04.038Nguyen, T. T., Aouine, M., & Millet, J. M. M. (2012). Optimizing the efficiency of MoVTeNbO catalysts for ethane oxidative dehydrogenation to ethylene. Catalysis Communications, 21, 22-26. doi:10.1016/j.catcom.2012.01.026Valente, J. S., Armendáriz-Herrera, H., Quintana-Solórzano, R., del Ángel, P., Nava, N., Massó, A., & López Nieto, J. M. (2014). Chemical, Structural, and Morphological Changes of a MoVTeNb Catalyst during Oxidative Dehydrogenation of Ethane. ACS Catalysis, 4(5), 1292-1301. doi:10.1021/cs500143jTHORSTEINSON, E. (1978). The oxidative dehydrogenation of ethane over catalysts containing mixed oxides of molybdenum and vanadium. Journal of Catalysis, 52(1), 116-132. doi:10.1016/0021-9517(78)90128-8Ishikawa, S., Yi, X., Murayama, T., & Ueda, W. (2014). Heptagonal channel micropore of orthorhombic Mo3VOx as catalysis field for the selective oxidation of ethane. Applied Catalysis A: General, 474, 10-17. doi:10.1016/j.apcata.2013.07.050Ishikawa, S., Yi, X., Murayama, T., & Ueda, W. (2014). Catalysis field in orthorhombic Mo3VOx oxide catalyst for the selective oxidation of ethane, propane and acrolein. Catalysis Today, 238, 35-40. doi:10.1016/j.cattod.2013.12.054Grasselli, R. K., Burrington, J. D., Buttrey, D. J., DeSanto Jr., P., Lugmair, C. G., Volpe Jr., A. F., & Weingand, T. (2003). Topics in Catalysis, 23(1/4), 5-22. doi:10.1023/a:1024859917786Grasselli, R. K., Lugmair, C. G., Volpe Jr., A. F., Andersson, A., & Burrington, J. D. (2010). Enhancement of acrylic acid yields in propane and propylene oxidation by selective P Doping of MoV(Nb)TeO-based M1 and M2 catalysts. Catalysis Today, 157(1-4), 33-38. doi:10.1016/j.cattod.2010.01.044Grasselli, R. K., Lugmair, C. G., & Volpe, A. F. (2011). Towards an Understanding of the Reaction Pathways in Propane Ammoxidation Based on the Distribution of Elements at the Active Centers of the M1 Phase of the MoV(Nb,Ta)TeO System. Topics in Catalysis, 54(10-12), 595-604. doi:10.1007/s11244-011-9681-2Grasselli, R. K. (2014). Site isolation and phase cooperation: Two important concepts in selective oxidation catalysis: A retrospective. Catalysis Today, 238, 10-27. doi:10.1016/j.cattod.2014.05.036Ramli, I., Botella, P., Ivars, F., Pei Meng, W., Zawawi, S. M. M., Ahangar, H. A., … Nieto, J. M. L. (2011). Reflux method as a novel route for the synthesis of MoVTeNbOx catalysts for selective oxidation of propane to acrylic acid. Journal of Molecular Catalysis A: Chemical, 342-343, 50-57. doi:10.1016/j.molcata.2011.04.009Naraschewski, F. N., Praveen Kumar, C., Jentys, A., & Lercher, J. A. (2011). Phase formation and selective oxidation of propane over MoVTeNbOx catalysts with varying compositions. Applied Catalysis A: General, 391(1-2), 63-69. doi:10.1016/j.apcata.2010.07.005Blasco, T., Botella, P., Concepción, P., López Nieto, J. M., Martinez-Arias, A., & Prieto, C. (2004). Selective oxidation of propane to acrylic acid on K-doped MoVSbO catalysts: catalyst characterization and catalytic performance. Journal of Catalysis, 228(2), 362-373. doi:10.1016/j.jcat.2004.08.036YANG, X., FENG, R., JI, W., & AU, C. (2008). Characterization and evaluation of MoVTeNb mixed metal oxide catalysts fabricated via hydrothermal process with ultrasonic pretreatment for propane partial oxidation. Journal of Catalysis, 253(1), 57-65. doi:10.1016/j.jcat.2007.10.020GAFFNEY, A., CHATURVEDI, S., CLARKJR, M., HAN, S., LE, D., RYKOV, S., & CHEN, J. (2005). Characterization and catalytic studies of PVD synthesized Mo/V/Nb/Te oxide catalysts. Journal of Catalysis, 229(1), 12-23. doi:10.1016/j.jcat.2004.09.013Espinal, L., Malinger, K. A., Espinal, A. E., Gaffney, A. M., & Suib, S. L. (2007). Preparation of Multicomponent Metal Oxides Using Nozzle Spray and Microwaves. Advanced Functional Materials, 17(14), 2572-2579. doi:10.1002/adfm.200600744Kolen’ko, Y. V., Amakawa, K., d’ Alnoncourt, R. N., Girgsdies, F., Weinberg, G., Schlögl, R., & Trunschke, A. (2012). Unusual Phase Evolution in MoVTeNb Oxide Catalysts Prepared by a Novel Acrylamide-Gelation Route. ChemCatChem, 4(4), 495-503. doi:10.1002/cctc.201100451Concepción, P., Hernández, S., & Nieto, J. M. L. (2011). On the nature of active sites in MoVTeO and MoVTeNbO catalysts: The influence of catalyst activation temperature. Applied Catalysis A: General, 391(1-2), 92-101. doi:10.1016/j.apcata.2010.05.011Botella, P., García-González, E., López Nieto, J. M., & González-Calbet, J. M. (2005). MoVTeNbO multifunctional catalysts: Correlation between constituent crystalline phases and catalytic performance. Solid State Sciences, 7(5), 507-519. doi:10.1016/j.solidstatesciences.2005.01.012Beato, P., Blume, A., Girgsdies, F., Jentoft, R. E., Schlögl, R., Timpe, O., … Mohd Salim, L. (2006). Analysis of structural transformations during the synthesis of a MoVTeNb mixed oxide catalyst. Applied Catalysis A: General, 307(1), 137-147. doi:10.1016/j.apcata.2006.03.014Celaya Sanfiz, A., Hansen, T. W., Girgsdies, F., Timpe, O., Rödel, E., Ressler, T., … Schlögl, R. (2008). Preparation of Phase-Pure M1 MoVTeNb Oxide Catalysts by Hydrothermal Synthesis—Influence of Reaction Parameters on Structure and Morphology. Topics in Catalysis, 50(1-4), 19-32. doi:10.1007/s11244-008-9106-zOzeki, T., Kihara, H., & Ikeda, S. (1988). Study of equilibria in 0.03 mM molybdate acidic aqueous solutions by factor analysis applied to ultraviolet spectra. Analytical Chemistry, 60(19), 2055-2059. doi:10.1021/ac00170a014Tytko, K.-H., & Schönfeld, B. (1975). Über Isopolymolybdatfeststoffe und deren Beziehung zu Isopolymolybdationen in wäßriger Lösung / Concerning Solid Isopolymolybdates and their Relation to Isopolymolybdate Ions in Aqueous Solution. Zeitschrift für Naturforschung B, 30(7-8), 471-484. doi:10.1515/znb-1975-7-801Müller, A., Krickemeyer, E., Bögge, H., Schmidtmann, M., & Peters, F. (1998). Organizational Forms of Matter: An Inorganic Super Fullerene and Keplerate Based on Molybdenum Oxide. Angewandte Chemie International Edition, 37(24), 3359-3363. doi:10.1002/(sici)1521-3773(19981231)37:243.0.co;2-jLivage, J. (2010). Hydrothermal Synthesis of Nanostructured Vanadium Oxides. Materials, 3(8), 4175-4195. doi:10.3390/ma3084175C. F. Baes Jr and R. E.Mesmer , in The Hydrolysis of Cations , Wiley N.Y. , 1970Tsuji, H., & Koyasu, Y. (2002). Synthesis of MoVNbTe(Sb)OxComposite Oxide Catalysts via Reduction of Polyoxometalates in an Aqueous Medium. Journal of the American Chemical Society, 124(20), 5608-5609. doi:10.1021/ja0122344Maksimovskaya, R. I., Bondareva, V. M., & Aleshina, G. I. (2008). NMR Spectroscopic Studies of Interactions in Solution during the Synthesis of MoVTeNb Oxide Catalysts. European Journal of Inorganic Chemistry, 2008(31), 4906-4914. doi:10.1002/ejic.200800500Griffith, W. P., & Lesniak, P. J. B. (1969). Raman studies on species in aqueous solutions. Part III. Vanadates, molybdates, and tungstates. Journal of the Chemical Society A: Inorganic, Physical, Theoretical, 1066. doi:10.1039/j19690001066Butler, I. S., El-Sherbeny, H. A. M., Kenawy, I. M., & Mostafa, S. I. (2013). Synthesis and spectroscopic characterization of complexes of Cr(III), Cr(VI), Cu(III), Zn(II), Mo(VI), Pd(II), Ag(III), Au(III) and W(VI) with telluric acid. Journal of Molecular Structure, 1036, 510-520. doi:10.1016/j.molstruc.2012.11.017Müller, A., Kögerler, P., & Dress, A. W. M. (2001). Giant metal-oxide-based spheres and their topology: from pentagonal building blocks to keplerates and unusual spin systems. Coordination Chemistry Reviews, 222(1), 193-218. doi:10.1016/s0010-8545(01)00391-5Botto, I. L., Cabello, C. I., & Thomas, H. J. (1997). (NH4)6[TeMo6O24]·7H2O Anderson phase as precursor of the TeMo5O16 catalytic phase: thermal and spectroscopic studies. Materials Chemistry and Physics, 47(1), 37-45. doi:10.1016/s0254-0584(97)80025-9Sun, Y., Liu, J., & Wang, E. (1986). Preparation and properties of some new 6-heteropoly-tellurate compounds of tungsten and molybdenum containing vanadium. Inorganica Chimica Acta, 117(1), 23-26. doi:10.1016/s0020-1693(00)88061-5Yoshida, H., Tanaka, T., Yoshida, T., Funabiki, T., & Yoshida, S. (1996). Control of the structure of niobium oxide species on silica by the equilibrium adsorption method. Catalysis Today, 28(1-2), 79-89. doi:10.1016/0920-5861(95)00232-4Kubouchi, Y., Hayakawa, S., Namatame, H., & Hirokawa, T. (2012). Direct observation of fractional change of niobium ionic species in a solution by means of X-ray absorption fine structure spectroscopy. X-Ray Spectrometry, 41(4), 259-263. doi:10.1002/xrs.2390Prasetyoko, D., Ramli, Z., Endud, S., & Nur, H. (2005). Preparation and characterization of bifunctional oxidative and acidic catalysts Nb2O5/TS-1 for synthesis of diols. Materials Chemistry and Physics, 93(2-3), 443-449. doi:10.1016/j.matchemphys.2005.03.030Konya, T., Katou, T., Murayama, T., Ishikawa, S., Sadakane, M., Buttrey, D., & Ueda, W. (2013). An orthorhombic Mo3VOxcatalyst most active for oxidative dehydrogenation of ethane among related complex metal oxides. Catal. Sci. Technol., 3(2), 380-387. doi:10.1039/c2cy20444dOliver, J. (2004). The effect of pH on structural and catalytic properties of MoVTeNbO catalysts. Applied Catalysis A: General, 257(1), 67-76. doi:10.1016/s0926-860x(03)00632-

    Una propuesta para homogenizar la escritura y el uso de nombres comunes en mastozoología

    Get PDF
    The binomial classification system of Carlos Linnaeus (Species plantarum, 1753 [for Botany] and the tenth edition of Systema Naturae, 1758 [for Zoology]), came to fill a great gap in science, by systematically naming plants and animals, thus universalizing scientific communication (Stearn 1959, McGregor 2009, International Commission of Zoological Nomenclature 1999). This classification system has the great advantage of being common to all scientists on the planet and allows consistency regardless of language. However, much knowledge of species, especially mammals, comes from popular knowledge and from communities that have always been in direct contact with natural areas.El sistema de clasificación binomial de Carlos Linneo (Species plantarum, 1753 [para la Botánica] y la décima edición de Systema Naturae, 1758 [para la Zoología]),  vino a llenar un gran vacío en la ciencia, al nombrar de forma sistemática a las plantas y animales,universalizando de este modo la comunicación científica (Stearn 1959, McGregor 2009, Comisión Internacional de Nomenclatura Zoológica 1999). Este sistema de clasificación tiene la gran ventaja de ser común a todos los científicos del planeta y permite consistencia sin importar el idioma. Sin embargo, gran parte del conocimiento de las especies, en especial de mamíferos, proviene del conocimiento popular y de las comunidades que siempre  han estado en contacto directo con las áreas naturales

    Miopatía autoinmune necrotizante

    Get PDF
    Mujer de 21 años, procedente de Camisea, Cusco, con dos semanas de debilidad muscular progresiva que llegó inclusive a la falla ventilatoria, elevación extrema de crantina fosfocinasa sérica total, patrón miopático en la electromiografía y con presencia de necrosis masiva sin infiltrado inflamatorio en la biopsia muscular. La paciente mejoró clínica y por losestudios de laboratorio con el tratamiento inmunosupresor

    Proper cytoskeleton α‐tubulin distribution is concomitant to tyrosine phosphorylation during in vitro capacitation and acrosomal reaction in human spermatozoa

    Get PDF
    Spermatozoa motility is a key parameter during the fertilization process. In this context, spermatozoa tyrosine protein phosphorylation and an appropriate cytoskeleton α‐tubulin distribution are some of the most important physiological events involved in motility. However, the relationship between these two biomarkers remains poorly defined. Here, we characterized simultaneously by immunocytochemistry the α‐tubulin (TUBA4A) distribution and the tyrosine phosphorylation at flagellum before capacitation, during different capacitation times (1 and 4 hr), and after acrosome reaction induction in human spermatozoa. We found that the absence of spermatozoa phosphorylation in tyrosine residues positively and significantly correlated (p < 0.05) with the terminal piece α‐tubulin flagellar distribution in all physiological conditions. Conversely, we observed a positive significant correlation (p < 0.01) between phosphorylated spermatozoa and continuous α‐tubulin distribution in spermatozoa flagellum, independently of the physiological condition. Similarly, the subpopulation of spermatozoa with tyrosine phosphorylated and continuous α‐tubulin increases with longer capacitation times and after the acrosome reaction induction. Overall, these findings provide novel insights into the post‐transcriptional physiological events associated to α‐tubulin and the tyrosine phosphorylation during fertilization, which present potential implications for the improvement of spermatozoa selection methods.This research was supported by Human Fertility Cathedra of the University of Alicante, VIOGROB-186, and the project of the Ministry of Economy and Competitiveness AGL2015-70159-P

    Uncertainty Estimation for Performance Evaluation of a Confocal Microscope as Metrology Equipment

    Full text link
    Both in industry and research, the quality control of micrometric manufactured parts is based on the measurement of parameters whose traceability is sometimes difficult to guarantee. In some of these parts, the confocal microscopy shows great aptitudes to characterize a measurand qualitatively and quantitatively. The confocal microscopy allows the acquisition of 2D and 3D images that are easily manipulated. Nowadays, this equipment is manufactured by many different brands, each of them claiming a resolution probably not in accord to their real performance. The Laser Center (Technical University of Madrid) has a confocal microscope to verify the dimensions of the micro mechanizing in their own research projects. The present study pretends to confirm that the magnitudes obtained are true and reliable. To achieve this, a methodology for confocal microscope calibration is proposed, as well as an experimental phase for dimensionally valuing the equipment by 4 different standard positions, with its seven magnifications and the six objective lenses that the equipment currently has, in the x–y and z axis. From the results the uncertainty will be estimated along with an effect analysis of the different magnifications in each of the objective lenses

    Emociones y psicoterapia: caminos e intersecciones

    Get PDF
    En este libro, dirigido a profesionales y estudiantes del campo de la psicología, se reúnen diversas investigaciones centradas en las emociones desde las dimensiones psicológica, social y cultural y despliega diversas formas de trabajo, regulación, expresión y reconfiguración emocional en aras de un mayor bienestar psicológico. Como parte del alivio psicológico, las emociones son condición que favorece el trabajo psicoterapéutico para generar condiciones de bienestar en las personas y afrontar lo emocional desde la psicoterapia, remite al tema de la pertenencia y la identidad; por tanto, la comprensión del vínculo inquebrantable entre el cuerpo y las emociones resulta fundamental para su gestión.ITESO. A.C

    Removing Systemic Barriers to Equity, Diversity, and Inclusion: Report of the 2019 Plant Science Research Network Workshop “Inclusivity in the Plant Sciences”

    Get PDF
    A future in which scientific discoveries are valued and trusted by the general public cannot be achieved without greater inclusion and participation of diverse communities. To envision a path towards this future, in January 2019 a diverse group of researchers, educators, students, and administrators gathered to hear and share personal perspectives on equity, diversity, and inclusion (EDI) in the plant sciences. From these broad perspectives, the group developed strategies and identified tactics to facilitate and support EDI within and beyond the plant science community. The workshop leveraged scenario planning and the richness of its participants to develop recommendations aimed at promoting systemic change at the institutional level through the actions of scientific societies, universities, and individuals and through new funding models to support research and training. While these initiatives were formulated specifically for the plant science community, they can also serve as a model to advance EDI in other disciplines. The proposed actions are thematically broad, integrating into discovery, applied and translational science, requiring and embracing multidisciplinarity, and giving voice to previously unheard perspectives. We offer a vision of barrier-free access to participation in science, and a plant science community that reflects the diversity of our rapidly changing nation, and supports and invests in the training and well-being of all its members. The relevance and robustness of our recommendations has been tested by dramatic and global events since the workshop. The time to act upon them is now

    Neuroblastoma RAS viral oncogene homolog (N-RAS) deficiency aggravates liver injury and fibrosis.

    Get PDF
    Progressive hepatic damage and fibrosis are major features of chronic liver diseases of different etiology, yet the underlying molecular mechanisms remain to be fully defined. N-RAS, a member of the RAS family of small guanine nucleotide-binding proteins also encompassing the highly homologous H-RAS and K-RAS isoforms, was previously reported to modulate cell death and renal fibrosis; however, its role in liver damage and fibrogenesis remains unknown. Here, we approached this question by using N-RAS deficient (N-RAS-/-) mice and two experimental models of liver injury and fibrosis, namely carbon tetrachloride (CCl4) intoxication and bile duct ligation (BDL). In wild-type (N-RAS+/+) mice both hepatotoxic procedures augmented N-RAS expression in the liver. Compared to N-RAS+/+ counterparts, N-RAS-/- mice subjected to either CCl4 or BDL showed exacerbated liver injury and fibrosis, which was associated with enhanced hepatic stellate cell (HSC) activation and leukocyte infiltration in the damaged liver. At the molecular level, after CCl4 or BDL, N-RAS-/- livers exhibited augmented expression of necroptotic death markers along with JNK1/2 hyperactivation. In line with this, N-RAS ablation in a human hepatocytic cell line resulted in enhanced activation of JNK and necroptosis mediators in response to cell death stimuli. Of note, loss of hepatic N-RAS expression was characteristic of chronic liver disease patients with fibrosis. Collectively, our study unveils a novel role for N-RAS as a negative controller of the progression of liver injury and fibrogenesis, by critically downregulating signaling pathways leading to hepatocyte necroptosis. Furthermore, it suggests that N-RAS may be of potential clinical value as prognostic biomarker of progressive fibrotic liver damage, or as a novel therapeutic target for the treatment of chronic liver disease

    Efficacy and safety of baricitinib in hospitalized adults with severe or critical COVID‑19 (Bari‑SolidAct): a randomised, double‑blind, placebo‑controlled phase 3 trial

    Get PDF
    Background Baricitinib has shown efcacy in hospitalized patients with COVID-19, but no placebo-controlled trials have focused specifcally on severe/critical COVID, including vaccinated participants. Methods Bari-SolidAct is a phase-3, multicentre, randomised, double-blind, placebo-controlled trial, enrolling participants from June 3, 2021 to March 7, 2022, stopped prematurely for external evidence. Patients with severe/ critical COVID-19 were randomised to Baricitinib 4 mg once daily or placebo, added to standard of care. The primary endpoint was all-cause mortality within 60 days. Participants were remotely followed to day 90 for safety and patient related outcome measures. Results Two hundred ninety-nine patients were screened, 284 randomised, and 275 received study drug or placebo and were included in the modifed intent-to-treat analyses (139 receiving baricitinib and 136 placebo). Median age was 60 (IQR 49–69) years, 77% were male and 35% had received at least one dose of SARS-CoV2 vaccine. There were 21 deaths at day 60 in each group, 15.1% in the baricitinib group and 15.4% in the placebo group (adjusted absolute diference and 95% CI −0.1% [−8·3 to 8·0]). In sensitivity analysis censoring observations after drug discontinuation or rescue therapy (tocilizumab/increased steroid dose), proportions of death were 5.8% versus 8.8% (−3.2% [−9.0 to 2.7]), respectively. There were 148 serious adverse events in 46 participants (33.1%) receiving baricitinib and 155 in 51 participants (37.5%) receiving placebo. In subgroup analyses, there was a potential interaction between vaccination status and treatment allocation on 60-day mortality. In a subsequent post hoc analysis there was a signifcant interac‑ tion between vaccination status and treatment allocation on the occurrence of serious adverse events, with more respiratory complications and severe infections in vaccinated participants treated with baricitinib. Vaccinated partici‑ pants were on average 11 years older, with more comorbidities. Conclusion This clinical trial was prematurely stopped for external evidence and therefore underpowered to con‑ clude on a potential survival beneft of baricitinib in severe/critical COVID-19. We observed a possible safety signal in vaccinated participants, who were older with more comorbidities. Although based on a post-hoc analysis, these fnd‑ ings warrant further investigation in other trials and real-world studies
    corecore