89 research outputs found

    Matrix Effect in Oleate Micelles-Vesicles Transformation

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    It is accepted by many authors that the formation of closed molecular structures is a key step in the evolution of life. Oleate vesicles represent a good model system in this framework due to the fact that they self-assemble spontaneously and that fatty acids are considered as possible prebiotic structures. In this contribution, we will focus the attention on the transition from oleate micelles to oleic acid/oleate vesicles induced by a pH change. This transformation is strongly influenced by the presence of pre-formed vesicles. We called this phenomenon the matrix effect. The influence of pre-added POPC liposomes (POPC = 1-palmitoyl-2-oleoyl- {sn}-glycerol-3-phosphocholine) and oleic acido leate vesicles on the process rate and on the final size distribution will be discussed elucidating the main differences between these two system

    Matrix effect in oleate micelles-vesicles transformation

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    ISSN:0169-6149ISSN:1573-087

    Changes in tropical forest cover of Southeast Asia from 1990 to 2010

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    The study assesses the extent and trends of forest cover in Southeast Asia for the period 1990-2000-2010 and provides an overview on the main drivers of forest cover change. A systematic sample of 418 sites (10 km x 10 km size) located at the one-degree geographical confluence points and covered with satellite imagery at 30 m resolution is used for the assessment. For the analysis of satellite imagery techniques of image segmentation and automated classification were combined with visual interpretation and quality control, involving experts from Southeast Asian countries. Two forest cover classes, namely ‘Tree Cover’ and ‘Tree Cover Mosaic’, and three non-forest land cover classes were mapped. Area measures were derived for the individual sample sites and aggregated to regional statistical estimates, accounting for differences in sampling intensity due to geographical latitude, and extrapolating to uniform reference dates. For estimating the accuracy of our results an independent consistency assessment was performed from a subsample of 1572 mapping units, resulting in an overall agreement of > 85% for the general differentiation of forest cover versus non-forest cover. Forest cover in Southeast Asia is estimated at 268 Mha in 1990, dropping to 236 Mha in 2010, with annual change rates of 1.75 Mha (~0.67%) and 1.45 Mha (~0.59%) for the periods 1990-2000 and 2000-2010, respectively. The vast majority of forest cover loss (~ 2/3 for 2000-2010) occurred in insular Southeast Asia. Analysing the change patterns visible from satellite imagery and combining with the output of an expert consultation on drivers of forest change, the conversion of forest cover to cash crop plantations is ranked as the dominant driver of forest change in Southeast Asia, followed by selective logging and the establishment of tree plantations.JRC.H.3-Forest Resources and Climat

    Thermal decomposition of CuProp2: In-situ analysis of film and powder pyrolysis

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    The thermal decomposition of CuProp2 in the form of film and powder was studied in different atmospheres by means of thermal analysis techniques (TG-MS, TG-IR, EGA), chemical-structural methods (FTIR, XRD, EA) and computational thermochemistry (VASP/PBE). The decomposition mechanism in terms of volatiles evolved was disclosed with the aid of ab-initio modeling; it was found to be dependent on the gas diffusion in and out of the sample and accelerated by a humid atmosphere. In films, the copper redox behavior showed sensitivity to the residual atmosphere. Finally, the role of the metal center is discussed in the frame of a general decomposition mechanism for metal propionates

    An update on: molecular genetics of high-risk chronic lymphocytic leukemia

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    ABSTRACTIntroduction: During the past few years, new genomic approaches have elucidated the molecular genetics of chronic lymphocytic leukemia (CLL) to a large extent. As a consequence, specific hi..

    Assessing prognosis of chronic lymphocytic leukemia using biomarkers and genetics

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    Chronic lymphocytic leukemia (CLL) is a clinically and genetically heterogenous disease. Genomic studies have deciphered the pathogenesis of CLL and has allowed the identification of prognostic and..

    Relevance of the Formation of Intermediate Non-Equilibrium Phases in YBa2Cu3O7-x Film Growth by Transient Liquid-Assisted Growth

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    Transient liquid-assisted growth (TLAG) is a non-equilibrium ultrafast method to grow YBa2Cu3O7–x (YBCO) superconducting films at up to 100 nm/s using chemical solution deposition. In this work, we study the formation of non-equilibrium crystalline intermediate phases prior to the growth of YBCO through TLAG. We analyze the thermal decomposition and microstructural evolution of a propionate-based fluorine-free solution used as precursor to YBCO epitaxial films. Thermal analyses (TGA, DSC), coupled with techniques to monitor the volatiles (TG-IR), were applied in situ during film pyrolysis in humid O2, while the thermal evolution of the solid residue was characterized by infrared spectroscopy and X-ray diffraction, both ex situ and in situ in synchrotron radiation sources, and by scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) cross-sectional analysis. Unexpected effects, observed during the decomposition of the ternary solution, are the formation of intermediate non-equilibrium phases: Cu2O or Cu(0) and monoclinic BaCO3. We emphasize that working with anhydrous solutions and anhydrous deposition conditions promotes the formation of the expected equilibrium phases. Finally, in situ X-ray diffraction permits monitoring the influence of the non-equilibrium monoclinic BaCO3 phase on the formation of binary oxide phases, precursors of TLAG YBCO film growth. Understanding the evolution of non-equilibrium phases is shown to be fundamental for the control of the final YBCO film’s microstructure and performance, since the latter are strongly affected by the film’s thermal history after solution deposition.This work was funded by Ministerio de Ciencia, Innovation y Universidades (RTI2018-095853-B-C21 and RTI2018-095853-B-C22) cofinanced by the European Regional Development Fund, and the EU Ultrasupertape project (ERC ADG-2014-669504). We also acknowledge the Center of Excellence Severo Ochoa (SEV-2015-0496), the Generalitat de Catalunya (2017-SGR-1519) and the COST -action NANOCOHYBRI (CA16218). In situ FTIR experiments were performed at the MIRAS beamline of the ALBA Synchrotron with the collaboration of ALBA staff. We also thank the DiffAbs beamline at SOLEIL Synchrotron facility and the beamline staff support for the in situ XRD experiments. We thank the ICMAB, INA-Zaragoza and UdG scientific services and technical staff for the support on the experiments. S.R. thanks the Universitat de Girona (UdG) for the IFUdG grant. L.S. and J.J. also acknowledge their FPU-MINECO PhD grant.Peer reviewe

    Chemical and Microstructural Nanoscale Homogeneity in Superconducting YBa2Cu3O7-x Films Derived from Metal-Propionate Fluorine-free Solutions

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    Research involved in developing alternative energy sources has become a necessity to face global warming. In this context, superconductivity is an appealing solution to enhance clean electrical energy provided that lower production costs can be attained. By implementation of chemical solution deposition techniques and high-throughput growth methods, low-cost nanostructured epitaxial cuprate superconductors are timely candidates. Here, we present a versatile and tunable solution method suitable for the preparation of high-performance epitaxial cuprate superconducting films. Disregarding the renowned trifluoroacetate route, we center our focus on the transient liquid-assisted growth (TLAG) that meets the requirement of being a greener chemical process together with ultrafast growth rates beyond 100 nm/s. We developed a facile, fast, and cost-effective method, starting from the synthesis of metal-propionate powders of Y, Ba, and Cu of high purity and high yields, being the precursors of the fluorine-free solutions, which enable the chemical and microstructural nanoscale homogeneity of YBa2Cu3O7-x (YBCO) precursor films. These solutions present endured stability and enable precise tunability of the composition, concentration, porosity, and film thickness. Homogeneous precursor films up to thicknesses of 2.7 μm through eight layer multidepositions are demonstrated, thus establishing the correct basis for epitaxial growth using the fast kinetics of the TLAG process. YBCO films of 500 nm thickness with a critical current density of 2.6 MA/cm2 at 77 K were obtained, showing the correlation of precursor film homogeneity to the final YBCO physical properties.The authors acknowledge the European Research Council for the ULTRASUPERTAPE project (ERC-2014-ADG-669504), IMPACT project (ERC-2019-PoC-874964), and EU COST action for CA16218 (NANOCOHYBRI). The authors also acknowledge financial support from the Spanish Ministry of Science, Innovation and Universities through the “Severo Ochoa” Programme for Centres of Excellence in FUNFUTURE (CEX2019-000917-S), SUMATE projects (RTI2018-095853-B-C21, RTI2018-095853-B-C22 co-financed by the European Regional Development Fund, MCIU/AEI/FEDER, UE), and SUPERENERTECH projects (PID2021-127297OB-C21 and PID2021-127297OB-C22). The authors also thank support from the Catalan Government with 2017-SGR-1519 and Catalan energy network XRE4S (2018 XARDI 00002). L.S., D.G., and A.K. acknowledge financial support from the Spanish Ministry of Science, Innovation and Universities through the FPI grants PRE2019-090621, PRE2018-084537, and PRE2020-091817, respectively. L.S. and D.G. would like to thank the UAB PhD program in Materials Science, and A.K. would like to thank the UAB PhD program in Physics. A.Q. would like to thank the Spanish Ministry of Science, Innovation and Universities [“Juan de la Cierva” postdoctoral fellowship (grant no. IJC2018-035034-I)]. The authors thank the Scientific Services at ICMAB and ICN2 Electron Microscopy Division. The authors acknowledge the use of instrumentation as well as the technical advice provided by the National Facility ELECMI ICTS, node “Laboratorio de Microscopías Avanzadas” at the University of Zaragoza. The content of this paper is the object of a European patent application no. EP22382741.1 filed on 29/07/2022.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe

    Kinetic Control of Ultrafast Transient Liquid Assisted Growth of Solution-Derived YBa2Cu3O7-x Superconducting Films

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    Transient liquid assisted growth (TLAG) is an ultrafast non-equilibrium growth process mainly governed by kinetic parameters, which are only accessible through fast in situ characterizations. In situ synchrotron X-ray diffraction (XRD) analysis and in situ electrical resistivity measurements are used to derive kinetic diagrams of YBa2 Cu3 O7- x (YBCO) superconducting films prepared via TLAG and to reveal the unique peculiarities of the process. In particular, diagrams for the phase evolution and the YBCO growth rates have been built for the two TLAG routes. It is shown that TLAG transient liquids can be obtained upon the melting of two barium cuprate phases (and not just one), differentiated by their copper oxidation state. This knowledge serves as a guide to determine the processing conditions to reach high performance films at high growth rates. With proper control of these kinetic parameters, films with critical current densities of 2-2.6 MA cm-2 at 77 K and growth rates between 100-2000 nm s-1 are reached. These growth rates are 1.5-3 orders of magnitude higher than those of conventional methods.The authors acknowledge the European Research Council for the ULTRASUPERTAPE project (ERC-2014-ADG-669504), IMPACT project (ERC-2019-PoC-874964) and EU COST action for CA16218 (NANOCOHYBRI). The authors also acknowledge financial support from Spanish Ministry of Science and Innovation with PID2021-127297OB-C21 and PID2021-127297OB-C22, and from Spanish Ministry of Science, Innovation and Universities through the “Severo Ochoa” Program for Centers of Excellence in R&D (SEV-2015-0496 and CEX2019-000917-S), and from the Spanish Ministry of Economy and Competitiveness with the SUMATE project (RTI2018-095853-B-C21, RTI2018-095853-B-C22, co-financed by the European Regional Development Fund, MCIU/AEI/FEDER, UE). They also thank the Catalan Government (2017-SGR-1519) and the Catalan energy network XRE4S (2018 XARDI 00002) for their support. L.S., D.G., and A.K. acknowledge financial support from Spanish Ministry of Science, Innovation and Universities through the FPI grant PRE2019-090621, PRE2018-084537, and PRE2020-091817, respectively. L.So. and J.J. acknowledge financial support from Spanish Ministry for the FPU grants. S.R. thanks the Universitat de Girona for IFUdG grant and A.Q. thanks the Spanish Ministry of Science, Innovation and Universities (“Juan de la Cierva” postdoctoral fellowship [Grant no. IJC2018-035034-I]). The authors thank the Scientific Services at ICMAB and ICN2 Electron Microscopy Division. The authors acknowledge the use of instrumentation as well as the technical advice provided by the National Facility ELECMI ICTS, node “Laboratorio de Microscopías Avanzadas” at University of Zaragoza. The authors also acknowledge SOLEIL Synchrotron for provision of synchrotron radiation facilities and are grateful for assistance while using the DiffAbs beamline.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe
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