Universidadedo Porto

Porto, Portugal

Universidadedo Porto

Porto, Portugal
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Santos J.E.,Max Planck Institute for the Physics of Complex Systems | Santos J.E.,Universidadedo Porto | Santos J.E.,Max Planck Institute for Chemical Physics of Solids | Peres N.M.R.,University of Minho | And 4 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

We perform a phenomenological analysis of the problem of the electronic doping of a graphene sheet by deposited transition metal atoms, which aggregate in clusters. The sample is placed in a capacitor device such that the electronic doping of graphene can be varied by the application of a gate voltage and such that transport measurements can be performed via the application of a (much smaller) voltage along the graphene sample, as reported in the work of Pi. The analysis allows us to explain the thermodynamic properties of the device, such as the level of doping of graphene and the ionization potential of the metal clusters, in terms of the chemical interaction between graphene and the clusters. We are also able, by modeling the metallic clusters as perfectly conducting spheres, to determine the scattering potential due to these clusters on the electronic carriers of graphene and hence the contribution of these clusters to the resistivity of the sample. The model presented is able to explain the measurements performed by Pi on Pt-covered graphene samples at the lowest metallic coverages measured, and we also present a theoretical argument based on the above model that explains why significant deviations from such a theory are observed at higher levels of coverage. © 2011 American Physical Society.

Romera-Cardenas G.,CSIC - National Center for Biotechnology | Romera-Cardenas G.,Universidadedo Porto | Thomas L.M.,National Institute of Allergy and Infectious Diseases | Lopez-Cobo S.,CSIC - National Center for Biotechnology | And 3 more authors.
PLoS ONE | Year: 2016

Natural killer cells are cytotoxic lymphocytes important in immune responses to cancer and multiple pathogens. However, chronic activation of NK cells can induce a hyporesponsive state. The molecular basis of the mechanisms underlying the generation and maintenance of this hyporesponsive condition are unknown, thus an easy and reproducible mechanism able to induce hyporesponsiveness on human NK cells would be very useful to gain understanding of this process. Human NK cells treated with ionomycin lose their ability to degranulate and secrete IFN-γ in response to a variety of stimuli, but IL-2 stimulation can compensate these defects. Apart from reductions in the expression of CD11 a/CD18, no great changes were observed in the activating and inhibitory receptors expressed by these NK cells, however their transcriptional signature is different to that described for other hyporesponsive lymphocytes. This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.

Banea M.D.,Institute Engineering Mecanica IDMEC | Da Silva L.F.M.,Universidadedo Porto
Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications | Year: 2010

The application of adhesively bonded joints in structural components made of composite materials for automotive industry applications has increased significantly in recent years and provides many benefits that will ultimately lead to lighter-weight vehicles, fuel savings, and reduced emissions. The principal benefits are design flexibility, opportunity for part consolidation, and joining of dissimilar materials. While much work has been conducted in adhesive bonding for the aerospace industry, the automotive industry does not currently have a full portfolio of processes and methods for evaluating candidate adhesives for use in bonding structural automotive components. Aerospace techniques and materials are not generally applicable, since the automotive industry must be more cognizant of cost and high volume production. In this article, the performances of two different adhesive types, an epoxy and a polyurethane, have been studied through bulk specimen and adhesive jointtests.Results showedthat the failure loads of both the bulk test and joint test specimens vary with temperature and this needs to be considered in any design procedure. Also, for the polyurethane adhesive, the single lap joint is sufficient to determine the adhesive shear strength.

Amorim I.,Universidadedo Porto | Amorim I.,University of Porto | Taulescu M.A.,University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca | Day M.J.,University of Bristol | And 8 more authors.
Journal of Comparative Pathology | Year: 2016

Gastric disorders are common in dogs and are a major reason for veterinary consultation. In human medicine, the classification of gastric diseases based on histological features, genotypes and molecular phenotypes helps to better understand the characteristics of each subtype, and to improve early diagnosis, prevention and treatment. Canine gastric lesions often show strong histological similarities to their human counterparts. However, such conditions in the canine stomach are poorly studied and their cellular and molecular features are largely unknown. This article reviews the histopathological classification of inflammatory and neoplastic lesions of the canine stomach and provides an update on the application of molecular techniques within the field of canine gastric pathology. The canine disorders are compared with current knowledge of the equivalent human diseases. © 2015 Elsevier Ltd.

Martins M.,Universidadedo Porto | Custodio R.,Universidadedo Porto | Camejo A.,Universidadedo Porto | Almeida M.T.,Universidadedo Porto | And 2 more authors.
Journal of Biological Chemistry | Year: 2012

Listeria monocytogenes is an intracellular food-borne pathogen causing listeriosis in humans. This bacterium deploys an arsenal of virulence factors that act in concert to promote cellular infection. Bacterial surface proteins are of primary importance in the process of host cell invasion. They interact with host cellular receptors, inducing/modulating specific cellular responses. We previously identified Vip, a Listeria surface protein covalently attached to the bacterial cell wall acting as a key virulence factor. We have shown that Vip interacts with Gp96 localized at the surface of host cells during invasion and that this interaction is critical for a successful infection in vivo. To better understand the importance of Vip-Gp96 interaction during infection, we aimed to characterize this interaction at the molecular level. Here we demonstrate that, during infection, L. monocytogenes triggers the cellular redistribution of Gp96, inducing its exposure at the cell surface. Upon infection, Gp96 N-terminal domain is exposed to the extracellular milieu in L2071 fibroblasts and interacts with Vip expressed by Listeria. We identified Gp96 (Asp1-Leu 170) as sufficient to interact with Vip; however, we also showed that the region Tyr179-Leu390 of Gp96 is important for the interaction. Our findings unravel the Listeria-induced surface expression of Gp96 and the topology of its insertion on the plasma membrane and improve our knowledge on the Vip-Gp96 interaction during Listeria infection. © 2012 by The American Society for Biochemistry and Molecular Biology, Inc.

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