191 research outputs found

    A cooled telescope for measurements of the Near Infrared Cosmological Background at balloon altitude (TRIP Experiment)

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    A cooled telescope has been designed and prepared for measurements of both local and cosmological Near InfraRed Backgrounds in the waveband 1–5 mm at balloon altitude (40 km). The detection system consists of a linear array with 32 InSb pixels placed in the focal plane of the telescope, cryogenically cooled and thermally controlled. A short description is given of the main characteristics of the instrument and of the expected performances. The experiment, repeatedly tested in laboratory, flew in the 1995 summer from Palestine (Texas, USA)

    Evolutionary Games with Affine Fitness Functions: Applications to Cancer

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    We analyze the dynamics of evolutionary games in which fitness is defined as an affine function of the expected payoff and a constant contribution. The resulting inhomogeneous replicator equation has an homogeneous equivalent with modified payoffs. The affine terms also influence the stochastic dynamics of a two-strategy Moran model of a finite population. We then apply the affine fitness function in a model for tumor-normal cell interactions to determine which are the most successful tumor strategies. In order to analyze the dynamics of concurrent strategies within a tumor population, we extend the model to a three-strategy game involving distinct tumor cell types as well as normal cells. In this model, interaction with normal cells, in combination with an increased constant fitness, is the most effective way of establishing a population of tumor cells in normal tissue.Comment: The final publication is available at http://www.springerlink.com, http://dx.doi.org/10.1007/s13235-011-0029-

    ?-SiC NWs grown on patterned and MEMS silicon substrates

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    One-dimensional materials have become an attractive field of research due to their potential applications in physics, development of nanodevices and sensors. Nanowires (NW) are particularly interesting for their enhanced properties with respect to the bulk materials. Moreover the dimension of these nanostructures is comparable to those of the biological and chemical species being sensed. Silicon carbide in the form of NW is a material of great technological interest because of well known properties such as wide band gap, high temperature stability, extreme hardness, chemical inertness, biocompatibility. The deposition and the use of nano-patterned substrates as template in physics and biophysics is a first step to study adhesion of living cells and cell culture for biocompatibility and sensing. The fabrication of Micro Electrical Mechanics Systems (MEMS) with different geometries and patterned substrates for selective deposition can help to study the possibility to realize devices with higher performances. Here we present the growth of cubic silicon carbide nanowires on patterned silicon substrates and on silicon MEMS

    Cellular senescence is immunogenic and promotes anti-tumor immunity

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    Cellular senescence is a stress response that activates innate immune cells, but little is known about its interplay with the adaptive immune system. Here, we show that senescent cells combine several features that render them highly efficient in activating dendritic cells (DCs) and antigen-specific CD8 T cells. This includes the release of alarmins, activation of interferon signaling, enhanced MHC class I machinery, and presentation of senescence-specific self-peptides that can activate CD8 T cells. In the context of cancer, immunization with senescent cancer cells elicits strong anti-tumor protection mediated by DCs and CD8 T cells. Interestingly, this protection is superior to immunization with cancer cells undergoing immunogenic cell death. Finally, the induction of senescence in human primary cancer cells also augments their ability to activate autologous antigen-specific tumor-infiltrating CD8 lymphocytes. Our study indicates that senescent cancer cells can be exploited to develop efficient and protective CD8-dependent anti-tumor immune responses

    The efficacy of chemotherapy is limited by intratumoral senescent cells expressing PD-L2

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    Chemotherapy often generates intratumoral senescent cancer cells that strongly modify the tumor microenvironment, favoring immunosuppression and tumor growth. We discovered, through an unbiased proteomics screen, that the immune checkpoint inhibitor programmed cell death 1 ligand 2 (PD-L2) is highly upregulated upon induction of senescence in different types of cancer cells. PD-L2 is not required for cells to undergo senescence, but it is critical for senescent cells to evade the immune system and persist intratumorally. Indeed, after chemotherapy, PD-L2-deficient senescent cancer cells are rapidly eliminated and tumors do not produce the senescence-associated chemokines CXCL1 and CXCL2. Accordingly, PD-L2-deficient pancreatic tumors fail to recruit myeloid-derived suppressor cells and undergo regression driven by CD8 T cells after chemotherapy. Finally, antibody-mediated blockade of PD-L2 strongly synergizes with chemotherapy causing remission of mammary tumors in mice. The combination of chemotherapy with anti-PD-L2 provides a therapeutic strategy that exploits vulnerabilities arising from therapy-induced senescence. © 2024, The Author(s)

    Mechanical characterization of 3C-SiC grown on Si micromachined cantilever

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    Resonating microcantilever (MCs) are extremely sensitive mass detectors that have been successfully proposed as chemical, biological and environmental sensors [1]. However, recent works have demonstrated that variation of flexural rigidity due to localization of molecule absorption can induce a positive frequency shift larger than the negative one due to the added mass effect [2]. Goal of our research is to grown and pattern thin 3C-SiC films on Si MC to obtain a huge local increment of beam stiffness, exploiting the outstanding mechanical properties of such material (in particular, its large Young modulus)

    Structural and vibrational study of pseudocubic CdIn2Se4 under compression

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    This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Physical Chemistry C, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/jp5077565We report a comprehensive experimental and theoretical study of the structural and vibrational properties of a-CdIn2Se4 under compression. Angle-dispersive synchrotron X-ray diffraction and Raman spectroscopy evidence that this ordered-vacancy compound with pseudocubic structure undergoes a phase transition (7 GPa) toward a disordered rocksalt structure as observed in many other ordered-vacancy compounds. The equation of state and the pressure dependence of the Raman-active modes of this semiconductor have been determined and compared both to ab initio total energy and lattice dynamics calculations and to related compounds. Interestingly, on decreasing pressure, at similar to 2 GPa, CdIn2Se4 transforms into a spinel structure which, according to calculations, is energetically competitive with the initial pseudocubic phase. The phase behavior of this compound under compression and the structural and compressibility trends in AB(2)Se(4) selenides are discussed.This study was supported by the Spanish government MEC under Grant Nos: MAT2013-46649-C4-3-P, MAT2013-46649-C4-2-P, MAT2010-21270-C04-03/04, and CTQ2009-14596-C02-01, by MALTA Consolider Ingenio 2010 Project (CSD2007-00045) and by Generalitat Valenciana (GVA-ACOMP-2013-1012). A.M. and P.R-H. acknowledge computing time provided by Red Espanola de Supercomputacion (RES) and MALTA-Cluster, and also to S. Munoz-Rodriguez for providing a data-parsing application. J.A.S. acknowledges Juan de la Cierva fellowship program for financial support.Santamaría Pérez, D.; Gomis, O.; Pereira, ALJ.; Vilaplana Cerda, RI.; Popescu, C.; Sans Tresserras, JÁ.; Manjón Herrera, FJ.... (2014). Structural and vibrational study of pseudocubic CdIn2Se4 under compression. Journal of Physical Chemistry C. 118(46):26987-26999. https://doi.org/10.1021/jp5077565S26987269991184
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