107 research outputs found

    Ultrasonic triggering of giant magnetocaloric effect in MnAs thin films

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    Mechanical control of magnetic properties in magnetostrictive thin films offers the unexplored opportunity to employ surface wave acoustics in such a way that acoustic triggers dynamic magnetic effects. The strain-induced modulation of the magnetic anisotropy can play the role of a high frequency varying effective magnetic field leading to ultrasonic tuning of electronic and magnetic properties of nanostructured materials, eventually integrated in semiconductor technology. Here, we report about the opportunity to employ surface acoustic waves to trigger magnetocaloric effect in MnAs(100nm)/GaAs(001) thin films. During the MnAs magnetostructural phase transition, in an interval range around room temperature (0{\deg}C - 60{\deg}C), ultrasonic waves (170 MHz) are strongly attenuated by the phase coexistence (up to 150 dB/cm). We show that the giant magnetocaloric effect of MnAs is responsible of the observed phenomenon. By a simple anelastic model we describe the temperature and the external magnetic field dependence of such a huge ultrasound attenuation. Strain-manipulation of the magnetocaloric effect could be a further interesting route for dynamic and static caloritronics and spintronics applications in semiconductor technology

    TBL1 is required for the mesenchymal phenotype of transformed breast cancer cells

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    The epithelial-to-mesenchymal transition (EMT) and its reversion (MET) are related to tumor cell dissemination and migration, tumor circulating cell generation, cancer stem cells, chemoresistance, and metastasis formation. To identify chromatin and epigenetic factors possibly involved in the process of EMT, we compare the levels of expression of epigenetic genes in a transformed human breast epithelial cell line (HMEC-RAS) versus a stable clone of the same cell line expressing the EMT master regulator ZEB1 (HMEC-RAS-ZEB1). One of the factors strongly induced in the HMEC-RAS-ZEB1 cells was Transducin beta-like 1 (TBL1), a component of the NCoR complex, which has both corepressor and coactivator activities. We show that TBL1 interacts with ZEB1 and that both factors cooperate to repress the promoter of the epithelial gene E-cadherin (CDH1) and to autoactivate the ZEB1 promoter. Consistent with its central role, TBL1 is required for mesenchymal phenotypes of transformed breast epithelial and breast cancer cell lines of the claudin-low subtype. Importantly, a high expression of the TBL1 gene correlates with poor prognosis and increased proportion of metastasis in breast cancer patients, indicating that the level of TBL1 expression can be used as a prognostic marker.Ministerio de Economía y Competitividad BFU2014-53543-P, BFU2017-85420-RJunta de Andalucía BIO-32

    Servidor de datos y página web para el aprendizaje de SIG en la ingeniería forestal

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    Los Sistemas de Información geográfica (SIG) son una herramienta de trabajo habitual en el ámbito de la ingeniería forestal, tanto en la faceta de redacción de proyectos, como en la investigación sobre el medio ambiente y el territorio. Cada vez hay más información cartográfica disponible desde servidores de diferentes instituciones, por lo que consideramos que es muy útil contar con una herramienta de organización de la información. En el trabajo que se presenta, se pretende proporcionar a los estudiantes e investigadores en materia forestal un portal que contenga información actualizada y ordenada sobre los recursos existentes compatibles con los SIG. Por tanto constituiráuna herramienta de apoyo que facilitarála fase de documentación, búsqueda de datos compatibles y aprendizaje de las herramientas que sirven de base para el desarrollo de cualquier trabajo técnico o de investigación relacionado con el medio ambiente y el territorio que se apoye en los SIG

    Altered expression of cytokines in mice infected intranasally with two syncytial variants of Herpes simplex virus type 1

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    Immune evasion strategies are important for the onset and the maintenance of viral infections. Many viruses have evolved mechanisms to counteract or suppress the host immune response. We have previously characterized two syncytial (syn) variants of Herpes simplex 1 (HSV-1) strain F, syn14-1 and syn17-2, obtained by selective pressure with a natural carrageenan. These variants showed a differential pathology in vaginal and respiratory mucosa infection in comparison with parental strain. In this paper, we evaluated the modulation of immune response in respiratory mucosa by these HSV-1 variants. We observed altered levels of Tumor Necrosis Factor-α and Interleukin-6 in lungs of animals infected with the syn14-1 and syn17-2 variants compared with the parental strain. Also, we detected differences in the recruitment of immune cells to the lung in syn variants infected mice. Both variants exhibit one point mutation in the sequence of the gene of glycoprotein D detected in the ectodomain of syn14-1 and the cytoplasmic tail of syn17-2. Results obtained in the present study contribute to the characterization of HSV-1 syn variants and the participation of the cellular inflammatory response in viral pathogenesis.Fil: Artuso, María Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Linero, Florencia Natalia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Laboratorio de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gazzaniga, Silvina Noemí. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Scolaro, Luis Alberto. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Laboratorio de Virología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pujol, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Wainstok, Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Carlucci, Maria Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentin

    Epidemiologia molecular aplicada ao monitoramento de estirpes de Staphylococcus aureus na produção de queijo minas frescal.

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    Resumo: Foi realizado o monitoramento epidemiológico molecular de estirpes de Staphylococcus aureus potencialmente toxigênicas isoladas no processo de produção do queijo Minas frescal em micro-usina do Estado de São Paulo. Para tanto, foram realizadas seis amostragens durante o período de junho de 2008 a julho de 2009, de modo a perfazer um total de 140 amostras. Essas amostras foram colhidas da superfície dos tanques de recepção e estocagem do leite cru, da superfície do tanque de equilíbrio do leite pasteurizado, da rede de abastecimento de água, das tubulações e equipamentos, das mãos do manipulador e de queijos embalados prontos para consumo. As colônias isoladas em Agar Baird-Parker confirmadas como cocos Gram positivos e que mostravam-se positivas às provas de catalase, coagulase e da produção de acetoína, foram submetidas à extração do DNA bacteriano através da utilização do Kit Invitek - Uniscience®. A confirmação molecular da espécie dos isolados e a presença de enterotoxinas SEA, SEB, SEC, SED e da toxina TSST-1 foi realizada a partir da amplificação dos fragmentos de DNA cromossômico específico. Entre as 74 estirpes de estafilococos coagulase positivos isoladas, somente 41 (55.4%) amostras foram confirmadas como sendo Staphylococcus aureus, das quais 25 (61,0%) mostraram-se positivas na pesquisa de toxinas estafilocócicas. A enterotoxina de maior frequência identificada foi a SEA. As estirpes de Staphylococcus aureus toxigênico foram mais isoladas nas mãos do manipulador (16,0%), no leite cru do tanque de recepção (12,0%), no leite pasteurizado para elaboração do queijo (12,0%) e no queijo Minas frescal pronto para consumo (12,0%). [Molecular epidemiology applied to monitoring strains of staphylococcus Aureus in minas frescal cheese production]. Abstract: We studied the molecular epidemiology of Staphylococcus aureus strains potentially toxigenic, isolated from the production process of Minas frescal cheese in a small dairy plant in the state of São Paulo. For this, samples were taken during the period from June 2008 to July 2009. Samples were collected from the surface of the receiving and storage tanks of raw milk, the surface of the balance tank of pasteurized milk, the water supply system, the pipes and equipments, the hands of the handler and from the packaged cheese, totaling 140 samples. The colonies isolated on Baird-Parker Agar confirmed as Gram positive and positive for catalase, coagulase and acetoin production, were submitted to extraction of bacterial DNA using the Invitek - Uniscience® kit. Confirmation of the isolated species and enterotoxins SEA, SEB, SEC, SED and TSST-1 toxin was carried out through the amplification of specific fragments of chromosomal DNA. Among the 74 strains of isolated coagulase-positive staphylococci, only 41 (55.4%) strains were confirmed as Staphylococcus aureus, of which 25 (61.0%) were positive to the presence of staphylococcal toxins. The most frequently identified enterotoxin was SEA. The toxigenic strains of Staphylococcus aureus were more frequently isolated from hands of the handler (16.0%), raw milk receiving tank (12.0%), pasteurized milk for cheese making (12.0%) and fresh white cheese ready for consumption (12.0%)

    Pair Interaction between Two Catalytically Active Colloids

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    Due to the intrinsically complex non-equilibrium behavior of the constituents of active matter systems, a comprehensive understanding of their collective properties is a challenge that requires systematic bottom–up characterization of the individual components and their interactions. For self-propelled particles, intrinsic complexity stems from the fact that the polar nature of the colloids necessitates that the interactions depend on positions and orientations of the particles, leading to a 2d − 1 dimensional configuration space for each particle, in d dimensions. Moreover, the interactions between such non-equilibrium colloids are generically non-reciprocal, which makes the characterization even more complex. Therefore, derivation of generic rules that enable us to predict the outcomes of individual encounters as well as the ensuing collective behavior will be an important step forward. While significant advances have been made on the theoretical front, such systematic experimental characterizations using simple artificial systems with measurable parameters are scarce. Here, two different contrasting types of colloidal microswimmers are studied, which move in opposite directions and show distinctly different interactions. To facilitate the extraction of parameters, an experimental platform is introduced in which these parameters are confined on a 1D track. Furthermore, a theoretical model for interparticle interactions near a substrate is developed, including both phoretic and hydrodynamic effects, which reproduces their behavior. For subsequent validation, the degrees of freedom are increased to 2D motion and resulting trajectories are predicted, finding remarkable agreement. These results may prove useful in characterizing the overall alignment behavior of interacting self-propelling active swimmer and may find direct applications in guiding the design of active-matter systems involving phoretic and hydrodynamic interactions

    Profit and viability persistence: evidence from the Spanish agricultural sector

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    The literature focused on analyzing profit persistence in the agricultural sector is scarce. This paper contributes to reducing this gap by carrying out an empirical study of 10 types of farming in Spain based on a dynamic panel model with microeconomic data from a large sample of farms provided by the Spanish Farm Accountancy Data Network. The generalized method of moments system estimator is used to assess profit persistence, including all significant lagged profit rates explaining the adjustment of abnormal profits over time. Moreover, the dynamic of farms' economic performance is analyzed considering the return on assets as a dependent variable (i.e., measuring farms' profitability), as well as an alternative indicator that also accounts for opportunity costs (i.e., measuring farms' viability). The results show that profit and viability persistence in the farming sector are complex dynamic processes that depend on several lags of the aforementioned dependent variables (between 2 and 5 years), with high abnormal profit and viability persistence being widespread. In any case, heterogeneous persistence results are achieved depending on the type of farming. The differences found can be explained by disparities in several explanatory variables contributing to above- or below-average performance. The conclusions reached could lead to sounder decision-making regarding agricultural policy (i.e., farm subsidies) and competition policy (i.e., exceptions to competition law). [EconLit Citations: D41; L13; L22; L25; Q12; C23]

    Effect of cattle trampling and farm machinery traffic on soil compaction of an Entic Haplustoll in a semiarid region of Argentina

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    Soil compaction has detrimental effects on the physical, mechanical and hydraulic properties of soils, and affects important soil processes and function, and crop productivity. This work was conducted to investigate soil compaction impacts in integrated arable croppinglivestock systems managed under conventional tillage (CT) and no-tillage (NT). The work examined the combined effects of cattle trampling and farm machinery traffic on: soil strength, soil deformation, and water infiltration into soil. The following treatments were applied to soil (Entic Haplustoll, 60% sand) managed under CT and NT: three traffic intensities (1, 5, 7 passes) performed with light (2WD, 53 kN) and heavy (4WD, 100.4 kN) tractors, and two stocking densities (400 and 700 kg ha-1 ), respectively. Controls were also used to represent the condition of the soil without any effect of livestock or field traffic. In both tillage systems, soil penetration resistance (strength) increased and water infiltration into soil decreased as traffic intensities or stocking rates applied increased. There was a significant traffic intensity × stocking rate interaction, which influenced the depth and extent of soil compaction at depth. Despite these results, stubble grazing during fallow should not be discouraged as this practice offers mixed farming systems several agronomic and financial benefits. If stubble was to be grazed, the system would need to be carefully managed: (1) avoid ‘random’ traffic using permanent or semipermanent traffic paths to minimise the field wheeled area, (2) vacate livestock from the field, or confine it to a sacrificial area, when the soil water content exceeds a critical level above which soil damage is likely, and (3) maintain more than 60%–70% ground cover. Tillage repair treatments can be targeted to those sacrificial or ‘hot-spots’ areas so that localised, as supposed to widespread, compaction problems are rectified before the next crop is established

    Increasing the production of high-quality graphene nanosheet powder: The impact of electromagnetic shielding of the reaction chamber on the TIAGO torch plasma approach

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    Microwave-induced plasmas (MIPs), and specifically the TIAGO device (Torche à Injection Axiale sur Guide d’Ondes), offer a streamlined, cost-effective, and environmentally friendly technique for producing high-quality graphene powder in a reaction chamber by a single-step process through ethanol decomposition. To optimize graphene synthesis process, a pivotal move involves minimizing energy dissipation through radiation to maximize the available microwave energy input. Including a metallic shielding around the reaction chamber, essentially creating a Faraday cage, is proposed. The shielding strategy prevents radiation losses and results in a remarkable increase in solid material formation up to 22.8 %. This value, along with the emitted gases proportions and plasma volume increase, shows a correlation with conditions associated with higher input power. Crucially, the shielding of the reaction chamber does not modify graphene growth kinetics in the plasma, as confirmed by Optical Emission Spectroscopy. The synthesized material undergoes a thorough examination, employing diverse techniques like Raman spectroscopy, electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and Brunauer-Emmett-Teller (BET) analysis. These analyses underscore a consistent quality of graphene, unaffected by the shielding implementation. Therefore, electromagnetic shielding of the TIAGO torch discharge not only leads to a remarkable increase in solid material formation, thus energy yield, but does so without compromising the intrinsic properties and quality of the synthesized graphene

    Biomolecular condensates mediate bending and scission of endosome membranes

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    Multivesicular bodies are key endosomal compartments implicated in cellular quality control through their degradation of membrane-bound cargo proteins. The ATP-consuming ESCRT protein machinery mediates the capture and engulfment of membrane-bound cargo proteins through invagination and scission of multivesicular-body membranes to form intraluminal vesicles. Here we report that the plant ESCRT component FREE1 forms liquid-like condensates that associate with membranes to drive intraluminal vesicle formation. We use a minimal physical model, reconstitution experiments and in silico simulations to identify the dynamics of this process and describe intermediate morphologies of nascent intraluminal vesicles. Furthermore, we find that condensate-wetting-induced line tension forces and membrane asymmetries are sufficient to mediate scission of the membrane neck without the ESCRT protein machinery or ATP consumption. Genetic manipulation of the ESCRT pathway in several eukaryotes provides additional evidence for condensate-mediated membrane scission in vivo. We find that the interplay between condensate and machinery-mediated scission mechanisms is indispensable for osmotic stress tolerance in plants. We propose that condensate-mediated scission represents a previously undescribed scission mechanism that depends on the physicomolecular properties of the condensate and is involved in a range of trafficking processes. More generally, FREE1 condensate-mediated membrane scission in multivesicular-body biogenesis highlights the fundamental role of wetting in intracellular dynamics and organization
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