52 research outputs found

    Unraveling the nature of active sites onto copper/ceria-zirconia catalysts for low temperature CO oxidation

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    The aim of this research is an attempt to shed some light on the understanding of the nature of the active sites and the generated synergies in the copper/ceria-zirconia formulations for low temperature CO oxidation by means of the creation of copper entities with different physico-chemical nature. For this reason, several CuOx/ceria-zirconia catalysts, with different Cu contents and different methods to incorporate copper species, were synthesized. Focus was specially put in this case trying to link the results of CO oxidation catalytic tests with the CO-temperature programmed reduction profiles/approximate estimations and selected characterization parameters in order to find out correlations among catalysts' properties/reducibility and catalytic behaviors, especially those corresponding to the nature and roles of the different CuOx species in contact with ceria-based support on catalytic activity. Results reveal a significant improvement in CO conversion compared to the ceria-zirconia support by adding a small amount of copper loading (as low as 0.5 %), emphasizing the paramount role of copper incorporated by the method of IWI. From 0.5 up to 2% of copper loading, an interesting increase gradual trend in activity and reducibility can be noted. It should be mentioned that all the catalysts obtained by this procedure are more catalytically active towards CO oxidation than 1%Pt/Al2O3 at low temperatures (T < 130 degrees C). CO-TPR results show that the reducibility of these catalysts is in line with their CO oxidation activity. The method of preparation has been revealed as a critical variable in the catalytic performance, and quite similar catalytic activities can be reached from different synthesis methods and different copper contents, due to the similar nature and type of CuOx species generated over the catalysts' surface, identified by the CO-TPR profiles and the rest of characterization data. Finally, IWI method seems to be the best one among those tested, thus combining superior areas of both alpha and beta contributions assigned on CO-TPR profiles, which seem to be critical in the interpretation of the catalytic behaviors

    Scutoids are a geometrical solution to three-dimensional packing of epithelia

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    As animals develop, tissue bending contributes to shape the organs into complex three-dimensional structures. However, the architecture and packing of curved epithelia remains largely unknown. Here we show by means of mathematical modelling that cells in bent epithelia can undergo intercalations along the apico-basal axis. This phenomenon forces cells to have different neighbours in their basal and apical surfaces. As a consequence, epithelial cells adopt a novel shape that we term “scutoid”. The detailed analysis of diverse tissues confirms that generation of apico-basal intercalations between cells is a common feature during morphogenesis. Using biophysical arguments, we propose that scutoids make possible the minimization of the tissue energy and stabilize three-dimensional packing. Hence, we conclude that scutoids are one of nature's solutions to achieve epithelial bending. Our findings pave the way to understand the three-dimensional organization of epithelial organs.España Ministerio de Ciencia y Tecnología BFU2013-48988-C2-1-P and BFU2016-8079

    Resultados de la reparación quirúrgica Del ligamento deltoideo en las fracturas equivalentes bimaleolares

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    ObjetivoEl objetivo de este estudio es evaluar los resultados de la reparación quirúrgica del ligamento deltoideo en fracturas equivalente bimaleolares.Material y métodoEntre 2002 y 2009 fueron intervenidos 49 pacientes con fractura del maléolo peroneo y signos clásicos de lesión del ligamento deltoideo; finalmente se recuperaron para la revisión 44 pacientes. Se dividieron en 2 grupos: grupo A con 33 casos, en los que se reparó el ligamento deltoideo, y grupo B con 11 casos, donde el deltoideo fue tratado conservadoramente. Las fracturas fueron clasificadas según Lauge-Hansen y la AO/OTA. Para la valoración clínico-funcional se usó la escala de la American Orthopaedic Foot and Ankle Society (AOFAS) para el tobillo. Se registraron las complicaciones y reintervenciones.ResultadosTras un seguimiento medio de 12 meses, se obtuvo un resultado satisfactorio en ambos grupos, con una puntuación media final de 95 puntos en el grupo A y una de 94 en el grupo B, según la escala AOFAS. Hubo 2 infecciones, 1 intolerancia de la sutura medial, 1 algodistrofia y 4 casos precisaron retirada de material.ConclusionesNuestros resultados sugieren que la lesión del ligamento deltoideo puede ser reparada con buenos resultados funcionales. Y entendemos que, aunque los signos clásicos nos ayudan a sospechar la lesión, no son predictores fiables de la necesidad de reparación del lado medial.PurposeThe purpose of this study is to evaluate the result of surgical repair of deltoid ligament in fracture of the distal fibula upper or at the syndesmotic level.Materials and methodsBetween 2002 and 2009, 49 patients with distal fibula fractures and classical signs of deltoid ligament incompetence were operated, 44 were available for follow-up. Two groups: group A included 33 cases in whom deltoid ligament was treated by surgical repair, and group B, 11 cases who were treated conservatively. All fractures were classified according to Lauge-Hansen and AO/OTA. The AOFAS ankle score was used for clinical and functional evaluation. Complications and reinterventions were recorded.ResultsAt a mean follow-up of 12 months, a satisfactory functional result was obtained in both groups, with a mean final score of 95 points in group A and 94 in group B on the AOFAS scale. There were 2 infection, a medial suture intolerance, an algodystrophy and 4 hardware removed.ConclusionsOur findings suggest that a ruptured deltoid ligament can be repair with goods functional result. And we understand that although the classical signs help us to suspect a torn ligament, are not reliable predictors for surgical revision of the medial side

    Scutoids are a geometrical solution to three-dimensional packing of epithelia

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    As animals develop, tissue bending contributes to shape the organs into complex three-dimensional structures. However, the architecture and packing of curved epithelia remains largely unknown. Here we show by means of mathematical modelling that cells in bent epithelia can undergo intercalations along the apico-basal axis. This phenomenon forces cells to have different neighbours in their basal and apical surfaces. As a consequence, epithelial cells adopt a novel shape that we term “scutoid”. The detailed analysis of diverse tissues confirms that generation of apico-basal intercalations between cells is a common feature during morphogenesis. Using biophysical arguments, we propose that scutoids make possible the minimization of the tissue energy and stabilize three-dimensional packing. Hence, we conclude that scutoids are one of nature's solutions to achieve epithelial bending. Our findings pave the way to understand the three-dimensional organization of epithelial organs

    Palynological investigations in the Orce Archaeological Zone, Early Pleistocene of Southern Spain

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    Palynological investigations in the Orce Archaeological Zone (OAZ) (Guadix-Baza Basin, Granada, Spain), Venta Micena 1 (VM1), Barranco Leon (BL) and Fuente Nueva 3 (FN3) are presented. This archaeological region is con-nected with the first Homo populations in Western Eurasia during the Early Pleistocene. The VM1 pollen record is characterized by Ephedra, and to a lesser extent, Pinus, Juniperus and evergreen Quercus, occassionally accompa-nied by Olea, Genisteae, Erica, deciduous Quercus, Alnus, Castanea, Fraxinus, Salix and Phillyrea. BL is dominated by Juniperus, Olea, Pinus, Poaceae, and evergreen Quercus. FN3 is characterized by an open Mediterranean woodland dominated by evergreen Quercus, Pinus, Juniperus and Olea, accompanied by deciduous Quercus, Castanea, Populus, Salix, Ulmus, Fraxinus, Pistacia, Phillyrea, Genisteae, Erica, Cistus, and Ephedra fragilis. Relic Tertiary taxa in OAZ include Carya, Pterocarya, Eucommia, Zelkova, and Juglans. The Early Pleistocene OAZ vegetation is a mosaic of different landscapes embracing mesophytes, thermophytes, xerophytes, xerothermophytes, and Mediterra-nean elements. These finds are compared with former pollen analyses in the region and beyond within the Ibe-rian Peninsula. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).Peer reviewe

    Author Correction: Scutoids are a geometrical solution to three-dimensional packing of epithelia.

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    The original version of this Article contained an error in ref. 39, which incorrectly cited 'Fristrom, D. & Fristrom, J. W. in The Development of Drosophila melanogaster (eds. Bate, M. & Martinez-Arias, A.) II, (Cold spring harbor laboratory press, 1993)'. The correct reference is 'Condic, M.L, Fristrom, D. & Fristrom, J.W. Apical cell shape changes during Drosophila imaginal leg disc elongation: a novel morphogenetic mechanism. Development 111: 23-33 (1991)'. Furthermore, the last sentence of the fourth paragraph of the introduction incorrectly omitted citation of work by Rupprecht et al. The correct citation is given below. These errors have now been corrected in both the PDF and HTML versions of the Article. Rupprecht, J.F., Ong, K.H., Yin, J., Huang, A., Dinh, H.H., Singh, A.P., Zhang, S., Yu, W. & Saunders, T.E. Geometric constraints alter cell arrangements within curved epithelial tissues. Mol. Biol. Cell 28, 3582-3594 (2017)

    A multi-proxy approach to the palaecological reconstruction of the Orce Basin Archaeological Zone (Granada, Spain)

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    Comunicación oral presentada en XXI INQUA Congress. July 14th – 20th 2023, Rome (Italy)The Orce Basin Archaeological Zone (OZAB, Granada, Spain) extends over a surface area of some > 8.5 km2 and constitutes one of the richest Pleistocene vertebrate fossil records in western Europe including one of the oldest hominin presence in this part of Eurasia. Exceptionally rich collections of stone tools have been excavated from both of the Orce Oldowan sites: Barranco León (BL) (1.4 Ma) and Fuente Nueva 3 (FN3) (1.2 Ma), while BL has yielded a hominin deciduous lower molar. We present a multi-proxy approach to determine the palaeoeocological context of these first hominin settlements in Western Europe. By combining results from macrovertebrates, microvertebrates, as well as from pollen and stable isotopes from macrovertebrate tooth enamel, we determine whether the palaeo landscapes were dominated by savanna or open woodland. The results reveal the regional specificities of the OAZB, and also allow us to infer local features within the Orce sites. Overall, our data reveal the dominance of a typically Mediterranean climate and landscape since 1.8 Ma ago. The climatic conditions were generally more humid than at present, with warmer temperatures during the coldest months, indicating a higher net primary productivity (NPP). We find that precipitation and NPP appear to have been limiting factors for hominin presence in the OAZB. Thus, at the older palaeontological site of Venta Micena (1.6 Ma), climatic conditions appear to have been less compatible with hominin presence than during the BL and FN3 sequences, when early hominins inhabiting the OAZB were able to cope with changing climatic and environmental settings. Lastly, the comparison of the isotopic results of the Orce sites with those of the contemporaneous Shungura Formation (Ethiopia) reveals that the habitat in the westernmost part of Eurasia was distinctly unlike a typical African savanna

    Not seen before. Unveiling depositional context and Mammuthus meridionalis exploitation at Fuente Nueva 3 (Orce, southern Iberia) through taphonomy and microstratigraphy

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    Meat consumption by early hominins is a hotly debated issue. A key question concerns their access to large mammal carcasses, including megafauna. Currently, the evidence of anthropic cut marks on proboscidean bones older than -or close to- 1.0 Ma are restricted to the archaeological sites of Dmanisi (Georgia), Olduvai (Tanzania), Gona (Ethiopia), Olorgesailie (Kenya) and La Boella (Spain). During an inspection of the almost complete carcass of Mammuthus meridionalis (FN3-5-MPS) from the Oldowan site of Fuente Nueva 3 (Orce, Spain, c. 1.2 Ma), a few traces compatible with human-made cut marks and carnivore tooth marks were found. From this finding and previous interpretations the following questions arise: When and under what conditions was FN3-5-MPS deposited? What is the nature of the marks found on the surface of the bones of this mammoth? To answer, we have conducted a high-resolution analysis of these remains, combining both taphonomic and microstratigraphic data. Our results, using microstratigraphic and micromorphological analyses of sediments based on thin-sections, show that this individual was deposited in a marshy environment. Subsequently, the carcass was exploited by hominins and large felids that left their marks on the surface of some of its bones. For this purpose, the identification and characterisation of both cut marks and tooth marks were performed using high-resolution 3D modelling, geometric morphometrics, and artificially intelligent algorithms. Based on the anatomical position of both the cut and tooth marks, we propose that both the hominins and the saber-toothed cats had early access to the animal. Finally, this paper shows how an interdisciplinary approach can shed detailed light on the particular story regarding the death and processing of the carcass of a female mammoth, deposited at Fuente Nueva 3.This research has been carried out thanks to projects PID 2021.125098NB.I00 funding by MCIN/AEI/10.13039/501100011033/FEDER Una manera de hacer Europa and ProyExcel_00274 funding by Dirección General de Planificación de la Investigación (Consejería de Universidad, Investigación e Innovación, Junta de Andalucía). In addition, this research has been supported by the following projects of the Spanish government: PID2021-122533NB-I00, PID2021-123092NB-C21, PID2022-136832NB-I00. We also acknowledge the support provided by the PALARQ Foundation through the project Ref: PR2004_19/01

    Consensus Paper: Neuroimmune Mechanisms of Cerebellar Ataxias

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