306 research outputs found

    Centrosome and retroviruses: The dangerous liaisons

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    Centrosomes are the major microtubule organizing structures in vertebrate cells. They localize in close proximity to the nucleus for the duration of interphase and play major roles in numerous cell functions. Consequently, any deficiency in centrosome function or number may lead to genetic instability. Several viruses including retroviruses such as, Foamy Virus, HIV-1, JSRV, M-PMV and HTLV-1 have been shown to hamper centrosome functions for their own profit, but the outcomes are very different. Foamy viruses, HIV-1, JSRV, M-PMV and HTLV-1 use the cellular machinery to traffic towards the centrosome during early and/or late stages of the infection. In addition HIV-1 Vpr protein alters the cell-cycle regulation by hijacking centrosome functions. Enthrallingly, HTLV-1 Tax expression also targets the functions of the centrosome, and this event is correlated with centrosome amplification, aneuploidy and transformation

    Providing alternative measures for addressing adverse drug-drug interactions

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    First Online 30 March 2019Clinical Practice Guidelines (CPGs) are documents used in daily clinical practice that provide advice on how to best diagnose and treat diseases in the form of a list of clinical recommendations. When simultaneously applying multiple CPGs to patients, this can lead to complex multiple drug regimens (polypharmacy) with the potential for harmful combinations of drugs. The need to address these adverse drug events calls forth for systems capable of not only automatically represent the common potential conflicts or interactions that can happen when merging CPGs but also systems capable of providing conflict-free alternatives. This paper presents a solution that represents CPGs as Computer-Interpretable Guidelines (CIGs) and allows the automatic identification of drug conflicts and the provision of alternative measures to resolve these conflicts.This work has been supported by COMPETE: POCI-01-0145-FEDER-0070 43 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope UID/CEC/ 00319/2013. The work of Tiago Oliveira was supported by JSPS KAKENHI Grant Number JP18K18115

    Direct observation of the band gap transition in atomically thin ReS2_2

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    ReS2_2 is considered as a promising candidate for novel electronic and sensor applications. The low crystal symmetry of the van der Waals compound ReS2_2 leads to a highly anisotropic optical, vibrational, and transport behavior. However, the details of the electronic band structure of this fascinating material are still largely unexplored. We present a momentum-resolved study of the electronic structure of monolayer, bilayer, and bulk ReS2_2 using k-space photoemission microscopy in combination with first-principles calculations. We demonstrate that the valence electrons in bulk ReS2_2 are - contrary to assumptions in recent literature - significantly delocalized across the van der Waals gap. Furthermore, we directly observe the evolution of the valence band dispersion as a function of the number of layers, revealing a significantly increased effective electron mass in single-layer crystals. We also find that only bilayer ReS2_2 has a direct band gap. Our results establish bilayer ReS2_2 as a advantageous building block for two-dimensional devices and van der Waals heterostructures

    Kink far below the Fermi level reveals new electron-magnon scattering channel in Fe

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    Many properties of real materials can be modeled using ab initio methods within a single-particle picture. However, for an accurate theoretical treatment of excited states, it is necessary to describe electron-electron correlations including interactions with bosons: phonons, plasmons, or magnons. In this work, by comparing spin- and momentum-resolved photoemission spectroscopy measurements to many-body calculations carried out with a newly developed first-principles method, we show that a kink in the electronic band dispersion of a ferromagnetic material can occur at much deeper binding energies than expected (E_b=1.5 eV). We demonstrate that the observed spectral signature reflects the formation of a many-body state that includes a photohole bound to a coherent superposition of renormalized spin-flip excitations. The existence of such a many-body state sheds new light on the physics of the electron-magnon interaction which is essential in fields such as spintronics and Fe-based superconductivity.Comment: 6 pages, 2 figure

    Centrosomal pre-integration latency of HIV-1 in quiescent cells

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    Human immunodeficiency virus type 1 (HIV-1) efficiently replicates in dividing and non-dividing cells. However, HIV-1 infection is blocked at an early post-entry step in quiescent CD4+ T cells in vitro. The molecular basis of this restriction is still poorly understood. Here, we show that in quiescent cells, incoming HIV-1 sub-viral complexes concentrate and stably reside at the centrosome for several weeks. Upon cell activation, viral replication resumes leading to viral gene expression. Thus, HIV-1 can persist in quiescent cells as a stable, centrosome-associated, pre-integration intermediate

    Nanobubbles at GPa Pressure under Graphene

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    We provide direct evidence that irradiation of a graphene membrane on Ir with low-energy Ar ions induces formation of solid noble-gas nanobubbles. Their size can be controlled by thermal treatment, reaching tens of nanometers laterally and height of 1.5 nm upon annealing at 1080 \ub0C. Ab initio calculations show that Ar nanobubbles are subject to pressures reaching tens of GPa, their formation being driven by minimization of the energy cost of film distortion and loss of adhesion
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