186 research outputs found

    Vanadium redox flow batteries: Potentials and challenges of an emerging storage technology

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    open4noIn this paper an overview of Vanadium Redox Flow Battery technologies, architectures, applications and power electronic interfaces is given. These systems show promising features for energy storage in smart grid applications, where the intermittent power produced by renewable sources must meet strict load requests and economical opportunities. This paper reviews the vanadium-based technology for redox flow batteries and highlights its strengths and weaknesses, outlining the research lines that aim at taking it to full commercial success.openSpagnuolo, Giovanni, Guarnieri, Massimo; Mattavelli, Paolo; Petrone, Giovanni;Guarnieri, Massimo; Mattavelli, Paolo; Petrone, Giovanni; Spagnuolo, Giovann

    Tractor accelerated test on test rig

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    The experimental tests performed to validate a tractor prototype before its production, need a substantial financial and time commitment. The tests could be reduced using accelerated tests able to reproduce on the structural part of the tractor, the same damage produced on the tractor during real life in a reduced time. These tests were usually performed reproducing a particular harsh condition a defined number of times, as for example using a bumpy road on track to carry out the test in any weather condition. Using these procedures the loads applied on the tractor structure are different with respect to those obtained during the real use, with the risk to apply loads hard to find in reality. Recently it has been demonstrated how, using the methodologies designed for cars, it is possible to also expedite the structural tests for tractors. In particular, automotive proving grounds were recently successfully used with tractors to perform accelerated structural tests able to reproduce the real use of the machine with an acceleration factor higher than that obtained with the traditional methods. However, the acceleration factor obtained with a tractor on proving grounds is in any case reduced due to the reduced speed of the tractors with respect to cars. In this context, the goal of the paper is to show the development of a methodology to perform an accelerated structural test on a medium power tractor using a 4 post test rig. In particular, several proving ground testing conditions have been performed to measure the loads on the tractor. The loads obtained were then edited to remove the not damaging portion of signals, and finally the loads obtained were reproduced in a 4 post test rig. The methodology proposed could be a valid alternative to the use of a proving ground to reproduce accelerated structural tests on tractors

    Metal abundances in extremely distant Galactic old open clusters. II. Berkeley 22 and Berkeley 66

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    We report on high resolution spectroscopy of four giant stars in the Galactic old open clusters Berkeley~22 and Berkeley~66 obtained with HIRES at the Keck telescope. We find that [Fe/H]=0.32±0.19[Fe/H]=-0.32\pm0.19 and [Fe/H]=0.48±0.24[Fe/H]=-0.48\pm0.24 for Berkeley~22 and Berkeley~66, respectively. Based on these data, we first revise the fundamental parameters of the clusters, and then discuss them in the context of the Galactic disk radial abundance gradient. We found that both clusters nicely obey the most updated estimate of the slope of the gradient from \citet{fri02} and are genuine Galactic disk objects.Comment: 20 pages, 6 eps figures, accepted for publication in the Astronomical Journa

    Theoretical and experimental study on mechanical characterisation of a water drop impact on a solid surface

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    The drop impact phenomenon can be used to study many agricultural aspects related to the rainfall, runoff and irrigation, such as the stability of aggregated and the detachment of fine particles. The aim of this study was to study experimentally and numerically the water drop impact on a solid wall. In a first phase a simple experimental apparatus and basic theoretical concepts were used to investigate the influence of the drop speed on the impact pressure. In the second section, a finite element model able to reproduce the complex phenomenon observed in the experimental phase, was developed. The pressure values obtained by experimental measurement are similar to those calculated on the base of the energy conservation principle (average percentage difference of 15.6%). Numerical model was useful to obtain important information on pressure profile inside the drop and the impact pressure during the splash, at present hard to achieve experimentally. The model was used to estimate also an almost realistic dynamic behaviour of the spreading drop

    Rede de delivery de comida e seus atores: práticas de consumo e de mercado

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    O objetivo deste trabalho é compreender como práticas de consumo e de mercados são instituídas e moldadas a partir da mediação de aplicativos de serviços de entrega de comidas que operam em rede. Como fundamentação teórica, foram adotadas as abordagens de práticas de consumo e de mercados (Estudos de Mercado Construtivistas – EMC), articuladas com a teoria ator-rede e a digitalização. A pesquisa é de natureza qualitativa e foi realizada por meio de um estudo de caso na rede de delivery de comidas. Os resultados apresentados foram obtidos a partir da análise temática dos dados e evidenciaram que para compreender as mudanças que recaem em um ator, é preciso compreender os demais atores e as transformações que sofreram e provocaram. Notou-se como o processo de digitalização provocou mudanças na constituição do ator não humano, que, por sua vez, reestruturou os modos como ocorrem as translações na rede investigada. Além disso, a articulação de práticas de consumo e de mercado contribuem para a ampliação do escopo teórico adotada nesta pesquisa, uma vez que para a compreensão de uma determinada rede, deve-se conhecer seus atores e suas práticas como um todo

    Expression of CD38 in human neuroblastoma SH-SY5Y cells.

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    Human CD38 antigen is a 42–45 kDa type II transmembrane glycoprotein with a short N-terminal cytoplasmic domain and a long C-terminal extracellular region. It is widely expressed in different cell types including thymocytes, activated T cells, and terminally differentiated B cells (plasma cells) and it is involved in cellular proliferation and adhesion. CD38 acts as an ectocyclase that converts NAD+ to the Ca2+-releasing second messenger cyclic ADP-ribose (cADPR). It has been also demonstrated that increased extracellular levels of NAD+ and cADPR are involved in inflammatory diseases and in cellular damage, such as ischemia. In the present study, we have characterized the expression of CD38 in human neuroblastoma SH-SY5Y cell line. All-trans-retinoic acid (ATRA) treatment was used to induce cell differentiation. Our results indicate that: a) even if SH-SY5Y cells have a negative phenotype express CD38 at nuclear level, ATRA treatment does not influence this pattern; b) CD38 localizing to the nucleus may co-localize with p80-coilin positive nuclear-coiled bodies; c) purified nuclei, by Western blot determinations using anti-CD38 antibodies, display a band with a molecular mass of −42 kDa; d) SH-SY5Y cells show nuclear ADP-ribosyl cyclase due to CD38 activity; e) the basal level of CD38 mRNA shows a time-dependent increase after treatment with ATRA. These results suggest that the presence of constitutive fully functional CD38 in the SH-SY5Y nucleus has some important implications for intracellular generation of cADP-ribose and subsequent nucleoplasmic calcium release

    TERRITORIALIZATION OF EVERYDAY LIFE BASED ON GOVERNMENT INTERVENTIONS: THE CASE OF THIRD AGE GYMS (ATIS)

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    Ao articular de forma teórica o avanço sobre espaço e territórios no campo de Estudos Organizacionais com a abordagem sobre o cotidiano, o presente artigo busca compreender como ocorre a territorialização do cotidiano dos moradores de um determinado bairro a partir da produção do espaço urbano por meio de intervenções governamentais com a implantação de Academias da Terceira Idade (ATIs), que surgiram como uma estratégia para promoção da saúde e qualidade de vida, influenciada por um contexto marcado pela transição demográfica. O estudo tem uma perspectiva qualitativa e caráter descritivo. Os procedimentos metodológicos adotados envolveram a pesquisa documental e a realização de trabalho de campo com entrevistas com idosos que frequentam semanalmente uma ATI em um dos bairros de Maringá, PR, município brasileiro onde foi inaugurada a primeira ATI nacional. Os dados coletados foram analisados por meio da análise de conteúdo. Verificou-se que o espaço antes abandonado e sem uso por parte dos moradores do bairro é agora pautado pelas territorialidades cotidianas dos usuários, que o construíram diante de movimentos de apropriação e uso. Destaca-se, também, a intervenção governamental realizada sem impactos negativos para a população, de forma que a mesma apropriou-se de discursos que propagam os benefícios da ATI.Through a theoretical articulation of the advances on space and territories in the field of Organizational Studies with the approach to everyday life, this article seeks to understand how territorialization occurs in the everyday lives of the residents of a particular neighborhood, based on the production of the urban space by means of government interventions, with the implementation of Third Age Gyms (ATIs). ATIs emerged as a strategy to promote health and quality of life, influenced by a context of demographic transition. The study uses qualitative and descriptive perspectives. The methodological procedures involved document research and fieldwork with interviews with elderly people who attend an ATI weekly in one of the neighborhoods of Maringá, the Brazilian city where the first national ATI was launched. The data collected were analyzed through content analysis. It was found that the space, previously abandoned and unused by the residents of the neighborhood, is now guided by the everyday territorialities of the users, who built it by movements of appropriation and use. It is also highlighted that the government intervention was carried without negative impacts on the population, as they have appropriated the discourses that raised awareness of the benefits of the ATI

    Reusing RTL assertion checkers for verification of SystemC TLM models

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    The recent trend towards system-level design gives rise to new challenges for reusing existing RTL intellectual properties (IPs) and their verification environment in TLM. While techniques and tools to abstract RTL IPs into TLM models have begun to appear, the problem of reusing, at TLM, a verification environment originally developed for an RTL IP is still under-explored, particularly when ABV is adopted. Some frameworks have been proposed to deal with ABV at TLM, but they assume a top-down design and verification flow, where assertions are defined ex-novo at TLM level. In contrast, the reuse of existing assertions in an RTL-to-TLM bottom-up design flow has not been analyzed yet, except by using transactors to create a mixed simulation between the TLM design and the RTL checkers corresponding to the assertions. However, the use of transactors may lead to longer verification time due to the need of developing and verifying the transactors themselves. Moreover, the simulation time is negatively affected by the presence of transactors, which slow down the simulation at the speed of the slowest parts (i.e., RTL checkers). This article proposes an alternative methodology that does not require transactors for reusing assertions, originally defined for a given RTL IP, in order to verify the corresponding TLM model. Experimental results have been conducted on benchmarks with different characteristics and complexity to show the applicability and the efficacy of the proposed methodology

    Defective One- or Two-electron Reduction of the Anticancer Anthracycline Epirubicin in Human Heart RELATIVE IMPORTANCE OF VESICULAR SEQUESTRATION AND IMPAIRED EFFICIENCY OF ELECTRON ADDITION

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    One-electron quinone reduction and two-electron carbonyl reduction convert the anticancer anthracycline doxorubicin to reactive oxygen species (ROS) or a secondary alcohol metabolite that contributes to inducing a severe form of cardiotoxicity. The closely related analogue epirubicin induces less cardiotoxicity, but the determinants of its different behavior have not been elucidated. We developed a translational model of the human heart and characterized whether epirubicin exhibited a defective conversion to ROS and secondary alcohol metabolites. Small myocardial samples from cardiac surgery patients were reconstituted in plasma that contained clinically relevant concentrations of doxorubicin or epirubicin. In this model only doxorubicin formed ROS, as detected by fluorescent probes or aconitase inactivation. Experiments with cell-free systems and confocal laser scanning microscopy studies of H9c2 cardiomyocytes suggested that epirubicin could not form ROS because of its protonation-dependent sequestration in cytoplasmic acidic organelles and the consequent limited localization to mitochondrial one-electron quinone reductases. Accordingly, blocking the protonation-sequestration mechanism with the vacuolar H+-ATPase inhibitor bafilomycin A1 relocalized epirubicin to mitochondria and increased its conversion to ROS in human myocardial samples. Epirubicin also formed ∼60% less alcohol metabolites than doxorubicin, but this was caused primarily by its higher Km and lower Vmax values for two-electron carbonyl reduction by aldo/keto-reductases of human cardiac cytosol. Thus, vesicular sequestration and impaired efficiency of electron addition have separate roles in determining a defective bioactivation of epirubicin to ROS or secondary alcohol metabolites in the human heart. These results uncover the molecular determinants of the reduced cardiotoxicity of epirubicin and serve mechanism-based guidelines to improving antitumor therapies

    Adhesion to and biofilm formation on IB3-1 bronchial cells by Stenotrophomonas maltophilia isolates from cystic fibrosis patients

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    <p>Abstract</p> <p>Background</p> <p><it>Stenotrophomonas maltophilia </it>has recently gained considerable attention as an important emerging pathogen in cystic fibrosis (CF) patients. However, the role of this microorganism in the pathophysiology of CF lung disease remains largely unexplored. In the present study for the first time we assessed the ability of <it>S. maltophilia </it>CF isolates to adhere to and form biofilm in experimental infection experiments using the CF-derived bronchial epithelial IB3-1cell line. The role of flagella on the adhesiveness of <it>S. maltophilia </it>to IB3-1 cell monolayers was also assessed by using <it>fliI </it>mutant derivative strains.</p> <p>Results</p> <p>All <it>S. maltophilia </it>CF isolates tested in the present study were able, although at different levels, to adhere to and form biofilm on IB3-1 cell monolayers. Scanning electron and confocal microscopy revealed <it>S. maltophilia </it>structures typical of biofilm formation on bronchial IB3-1 cells. The loss of flagella significantly (P < 0.001) decreased bacterial adhesiveness, if compared to that of their parental flagellated strains. <it>S. maltophilia </it>CF isolates were also able to invade IB3-1 cells, albeit at a very low level (internalization rate ranged from 0.01 to 4.94%). Pre-exposure of IB3-1 cells to <it>P. aeruginosa </it>PAO1 significantly increased <it>S. maltophilia </it>adhesiveness. Further, the presence of <it>S. maltophilia </it>negatively influenced <it>P. aeruginosa </it>PAO1 adhesiveness.</p> <p>Conclusions</p> <p>The main contribution of the present study is the finding that <it>S. maltophilia </it>is able to form biofilm on and invade CF-derived IB3-1 bronchial epithelial cells, thus posing a rationale for the persistence and the systemic spread of this opportunistic pathogen in CF patients. Experiments using <it>in vivo </it>models which more closely mimic CF pulmonary tissues will certainly be needed to validate the relevance of our results.</p
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