572 research outputs found

    Mediastinal Mass in a Patient with Colorectal Cancer: A Diagnostic Challenge

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    The differential diagnosis of mediastinal masses involves many benign and malignant conditions, such as lymphadenopathies and cystic lesions. Metastatic mediastinal adenopathies are usually due to lung, esophagus, and stomach cancer and, rarely, due to colorectal cancer. Gastrointestinal duplication cysts are uncommon inherited lesions usually diagnosed during childhood and may involve the esophagus in 20% of cases. In adults, they are usually asymptomatic and diagnosed incidentally. We report the case of a 54-year-old male who recently underwent sigmoidectomy due to an obstructive colon adenocarcinoma. Staging computed tomography scan showed a hypodense lesion in the posterior mediastinum suggestive of metastatic adenopathy. Endoscopic ultrasound revealed a homogeneous and hypoechogenic lesion with intramural location in the upper esophagus, suggestive of a duplication esophageal cyst. Given the oncologic background and to exclude metastatic disease, endoscopic ultrasound-guided fine needle aspiration was performed, and a mucinous fluid was aspirated. The cytologic examination supported the ultrasonographic diagnostic hypothesis. This case highlights the role of endoscopic ultrasound in the differential diagnosis of mediastinal masses, particularly in oncologic patients, in order to rule out more ominous lesions.info:eu-repo/semantics/publishedVersio

    EQUIVALENT MODELS FOR PHOTOVOLTAIC CELL – A REVIEW

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    Over the years, the contribution of photovoltaic energy to an eco-friendly world is continually increasing. Photovoltaic (PV) cells are commonly modelled as circuits, so finding the appropriate circuit model parameters of PV cells is crucial for performance evaluation, control, efficiency computations and maximum power point tracking of solar PV systems. The problem of finding circuit model of solar PV cells is referred to as “PV cell equivalent model problem”. In this paper, the existing research works on PV cell model parameter estimation problem are classified according to error quali-quantitative analysis, number of parameters, translation equations and PV technology. The existent models were discussed pointing out its different levels of approximation. A qualitative comparative ranking was made and four models were found to be the best ones for simulating PV cells. Besides, based on the conducted review, some recommendations for future research are provided

    Distinguishing nanowire and nanotube formation by the deposition current transients

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    AbstractHigh aspect ratio Ni nanowires (NWs) and nanotubes (NTs) were electrodeposited inside ordered arrays of self-assembled pores (approximately 50 nm in diameter and approximately 50 μm in length) in anodic alumina templates by a potentiostatic method. The current transients monitored during each process allowed us to distinguish between NW and NT formation. The depositions were long enough for the deposited metal to reach the top of the template and form a continuous Ni film. The overfilling process was found to occur in two steps when depositing NWs and in a single step in the case of NTs. A comparative study of the morphological, structural, and magnetic properties of the Ni NWs and NTs was performed using scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometry, respectively.M. P. Proença and C. T. Sousa are thankful to FCT for the doctoral and postdoctoral grants SFRH/BD/43440/2008 and SFRH/BPD/82010/2011, respectively. J. Ventura acknowledges the financial support through FSE/POPH. M Vázquez thanks the Spanish Ministry of Economia y Competitividad, MEC, under project MAT2010-20798-C05-01. J. P. Araújo also thanks the Fundação Gulbenkian for its financial support within the ‘Programa Gulbenkian de Estímulo à Investigação Científica’. The authors acknowledge the funding from FCT through the Associated Laboratory - IN and project PTDC/FIS/105416/2008.Peer Reviewe

    Tailoring the Ti surface via electropolishing nanopatterning as a route to obtain highly ordered TiO2 nanotubes

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    Highly ordered TiO2 nanotubes (NTs) were synthesized by the electrochemical anodization of Tifoils subjected to electropolishing (EP) pre-treatment. We found that the Ti surface roughnessplays an important role in the onset of pore nucleation in enhancing the local focusing effect ofthe electrical field. Additionally, EP induces the formation of dimple structures on the metalsurface, which can work as a pre-pattern prior to anodization. These shallow ripples lead to apreferentially ordered pore nucleation, offering an organizational improvement of the anodicoxide NTs. We found that, depending on the EP applied potential, the roughness and the spatialperiod of the ripple-like structures varies from 82 nm and from 12230 nm, respectively. Suchtuning allowed us to focus on the influence of the initial Ti pre-surface topography features onthe NTs length, organization, and hexagonal arrangement quality, as well as diameter anddensity. Our results show that an EP under 10 V is the most suitable to obtain a small Ti surfaceroughness, the largest NT length (40% enhancement), and the effective improvement of theordered hexagonal NTs arrays over larger areas. Furthermore, the NTs dimensions (porediameters and density) were also found to depend on the initial Ti surface topography. The use ofoptimized EP allows us to obtain highly hexagonal self-ordered samples at a reduced timeand cost

    the State of Utah v. Brent Jay Sessions and Louis R. Dabbs : Brief of Appellant

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    Defendant, Brent Jay Sessions, Appeals from a Judgement of Guilty of Burglary In The Third Judicial District, In and For Salt Lake County, State of Utah, The Honorable Hal G, Taylor, Presiding

    The role of Cu length on the magnetic behaviour of Fe/Cu multi-segmented nanowires

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    CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOA set of multi-segmented Fe/Cu nanowires were synthesized by a two-step anodization process of aluminum substrates and a pulsed electrodeposition technique using a single bath. While both Fe segment length and diameter were kept constant to (30 +/- 7) and (45 +/- 5) nm, respectively, Cu length was varied between (15 +/- 5) and (120 +/- 10) nm. The influence of the non-magnetic layer thickness variation on the nanowire magnetic properties was investigated through first-order reversal curve (FORC) measurements and micromagnetic simulations. Our analysis confirmed that, in the multi-segmented Fe/Cu nanowires with shorter Cu segments, the dipolar coupling between Fe segments controls the nanowire magnetic behavior, and its performance is like that of a homogenous Fe nanowire array of similar dimensions. On the other hand, multi-segmented Fe/Cu nanowires with larger Cu segments act like a collection of non-interacting magnetic entities (along the nanowire axis), and their global behavior is mainly controlled by the neighbor-to-neighbor nanodisc dipolar interactions.87112CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO234513/2014-4sem informaçãoAgências de fomento estrangeiras apoiaram essa pesquisa, mais informações acesse artig

    Magnetic nanostructures for emerging biomedical applications

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    Magnetic nanostructures have been widely studied due to their potential applicability into several research fields such as data storage, sensing and biomedical applications. Focusing on the biomedical aspect, some new approaches deserve to be mentioned: cell manipulation and separation, contrast-enhancing agents for magnetic resonance imaging, and magnetomechanically induced cell death. This work focuses on understanding three different magnetic nanostructures, disks in the vortex state, synthetic antiferromagnetic particles and nanowires, first, by explaining their interesting properties and how they behave under an applied external field, before reviewing their potential applications for each of the aforementioned techniques.The authors acknowledge funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant Agreement No. 734801. C.R. and R.M. acknowledge funding from Basque Government Grant Nos. PIBA 2018-11 and IT1162-19, and Spanish Grant No. FIS2016-76058 (AEI/FEDER, UE). D.N. acknowledges the Spanish Ministry for Science, Innovation and Universities, for funding through the “Ramon y Cajal” program RYC-2017-22820. C.T. Sousa thanks FCT for financial support through the Investigador FCT program (Contract No. IF/01159/2015). R. Magalhães is grateful to the FCT SFRH/BD/148563/2019 PhD grant. This work was also supported by the Portuguese Fundação para a Ciência e a Tecnologia (FCT) and COMPETE 2020 (FEDER) under the projects POCI-01-0145-FEDER-028676/PTDC/CTM-CTM/28676/2017, POCI-01-0145/FEDER-032257/PTDC/FIS-OTI/32257/2017, POCI-01-0145-FEDER031302/PTDC/FIS-MAC/31302/2017, and POCI-01-0141-FEDER032527
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