94 research outputs found

    The Glucose Transporter 2 regulates CD8+ T cell function via environment sensing

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    T cell activation is associated with a profound and rapid metabolic response to meet increased energy demands for cell division, differentiation and development of effector function. Glucose uptake and engagement of the glycolytic pathway are major checkpoints for this event. Here we show that the low-affinity, concentration-dependent glucose transporter 2 (Glut2) regulates the development of CD8+ T cell effector responses in mice by promoting glucose uptake, glycolysis and glucose storage. Expression of Glut2 is modulated by environmental factors including glucose and oxygen availability and extracellular acidification. Glut2 is highly expressed by circulating, recently primed T cells, allowing efficient glucose uptake and storage. In glucose-deprived inflammatory environments, Glut2 becomes downregulated, thus preventing passive loss of intracellular glucose. Mechanistically, Glut2 expression is regulated by a combination of molecular interactions involving hypoxia-inducible factor-1 alpha, galectin-9 and stomatin. Finally, we show that human T cells also rely on this glucose transporter, thus providing a potential target for therapeutic immunomodulation

    Elastic scattering angular distribution for the 18O+48Ti collision at 275 MeV within the NUMEN project

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    In the context of the NUMEN project, the 18O + 48Ti collision at 275 MeV incident energy was studied for the first time. In the adopted multichannel approach, the elastic scattering was measured in order to deduce the initial state interaction and the corresponding optical potential. The angular distribution of elastic scattering was determined across a wide range of scattering angles

    One-neutron transfer reaction in the 18^{18}O + 48^{48}Ti collision at 275 MeV

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    The present article reports new data on the 48^{48}Ti(18^{18}O,17^{17}O)49^{49}Ti reaction at 275 MeV incident energy as part of the systematic research pursued within the NUMEN project. Supplementary measurements of the same reaction on 16^{16}O and 27^{27}Al targets were also performed in order to estimate the background arising from the use of a composite target (TiO2_{2} + 27^{27}Al). These data were analyzed under the same theoretical framework as those obtained with the titanium target in order to reinforce the conclusions of our analysis. Differential cross-section angular distribution measurements for the 17^{17}O8+^{8+} ejectiles were performed in a wide angular range by using the MAGNEX large acceptance magnetic spectrometer. The experimental results were analyzed within the distorted-wave and coupled-channels Born Approximation frameworks. The optical potentials at the entrance and exit channels were calculated in a double folding approach adopting the S\~ao Paulo potential, and the spectroscopic amplitudes for the projectile and target overlaps were obtained from large-scale shell model calculations. The differential cross-sections are well-described by the theoretical calculations, where a weak coupling to collective excitations of projectile and target is inferred. The sensitivity of transfer cross-sections on different model spaces adopted in nuclear structure calculations, is also discussed

    One-proton transfer reaction for the O 18 + Ti 48 system at 275 MeV

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    Single-nucleon transfer reactions are processes that selectively probe single-particle components of the populated many-body nuclear states. In this context, recent efforts have been made to build a unified description of the rich nuclear spectroscopy accessible in heavy-ion collisions. An example of this multichannel approach is the study of the competition between successive nucleon transfer and charge exchange reactions, the latter being of particular interest in the context of single and double beta decay studies. To this extent, the one-proton pickup reaction Ti48(O18,F19)Sc47 at 275 MeV was measured for the first time, under the NUMEN experimental campaign. Differential cross-section angular distribution measurements for the F19 ejectiles were performed at INFN-LNS in Catania by using the MAGNEX large acceptance magnetic spectrometer. The data were analyzed within the distorted-wave and coupled-channels Born approximation frameworks. The initial and final-state interactions were described adopting the São Paulo potential, whereas the spectroscopic amplitudes for the projectile and target overlaps were derived from shell-model calculations. The theoretical cross sections are found to be in very good agreement with the experimental data, suggesting the validity of the optical potentials and the shell-model description of the involved nuclear states within the adopted model space

    Study of single-nucleon transfer reactions in the 18O+48Ti collision at 275 MeV

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    The study of single-nucleon transfer reactions for the 18O+48Ti system was pursued at the energy of 275 MeV as part of a more systematic study which is undertaken within the NUMEN and NURE experimental campaigns. The aim is to measure the complete set of available reaction network which are characterized by the same initial and final-state wavefunctions as the more suppressed double charge exchange reactions. Understanding the degree of competition between successive nucleon transfer and double charge exchange reactions is crucial for the description of the meson-exchange mechanism. In this respect, angular distribution measurements for one- and twonucleon transfer reactions for the 18O+48Ti system were carried out at theMAGNEX facility of INFN-LNS in Catania. An overview of the data analysis for the 48Ti(18O,19F)47Sc and 48Ti(18O,17O)49Ti reactions will be presented

    The NUMEN heavy ion multidetector for a complementary approach to the neutrinoless double beta decay

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    Neutrinos are so far the most elusive known particles, and in the last decades many sophisticated experiments have been set up in order to clarify several questions about their intrinsic nature, in particular their masses, mass hierarchy, intrinsic nature of Majorana or Dirac particles. Evidence of the Neutrinoless Double-Beta Decay (NDBD) would prove that neutrinos are Majorana particles, thus improving the understanding of the universe itself. Besides the search for several large underground experiments for the direct experimental detection of NDBD, the NUMEN experiment proposes the investigation of a nuclear mechanism strongly linked to this decay: the Double Charge Exchange reactions (DCE). As such reactions share with the NDBD the same initial and final nuclear states, they could shed light on the determination of the Nuclear Matrix Elements (NMEs), which play a relevant role in the decay. The physics of DCE is described elsewhere in this issue, while the focus of this paper will be on the challenging experimental apparatus currently under construction in order to fulfil the requirements of the NUMEN experiment. The overall structure of the technological improvement to the cyclotron, along with the newly developed detection systems required for tracking and identifying the reaction products and their final excitation level are described

    A constrained analysis of the 40Ca(18O,18F)40K direct charge exchange reaction mechanism at 275 Mev

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    The40 Ca(18 O,18 F)40 K single charge exchange (SCE) reaction is explored at an incident energy of 275 MeV and analyzed consistently by collecting the elastic scattering and inelastic scattering data under the same experimental conditions. Full quantum-mechanical SCE calculations of the direct mechanism are performed by including microscopic nuclear structure inputs and adopting either a bare optical potential or a coupled channel equivalent polarization potential (CCEP) constrained by the elastic and inelastic data. The direct SCE mechanism describes the magnitude and shape of the angular distributions rather well, thus suggesting the suppression of sequential multi-nucleon transfer processes

    The NUMEN heavy ion multidetector for a complementary approach to the neutrinoless double beta decay

    Get PDF
    Neutrinos are so far the most elusive known particles, and in the last decades many sophisticated experiments have been set up in order to clarify several questions about their intrinsic nature, in particular their masses, mass hierarchy, intrinsic nature of Majorana or Dirac particles. Evidence of the Neutrinoless Double-Beta Decay (NDBD) would prove that neutrinos are Majorana particles, thus improving the understanding of the universe itself. Besides the search for several large underground experiments for the direct experimental detection of NDBD, the NUMEN experiment proposes the investigation of a nuclear mechanism strongly linked to this decay: the Double Charge Exchange reactions (DCE). As such reactions share with the NDBD the same initial and final nuclear states, they could shed light on the determination of the Nuclear Matrix Elements (NMEs), which play a relevant role in the decay. The physics of DCE is described elsewhere in this issue, while the focus of this paper will be on the challenging experimental apparatus currently under construction in order to fulfil the requirements of the NUMEN experiment. The overall structure of the technological improvement to the cyclotron, along with the newly developed detection systems required for tracking and identifying the reaction products and their final excitation level are described
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