2,672 research outputs found

    Invasive Meningococcal Disease Unraveling a Novel Mutation in the C5 Gene in a Portuguese Family

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    Although bacterial meningitis is a rare presentation of a congenital immunodeficiency, invasive meningococcal disease is classically associated with complement deficiencies. We report a patient from a consanguineous kindred presenting with an invasive meningococcal disease caused by serogroup B meningococcus that revealed an underlying C5 deficiency caused by a novel mutation in the C5 gene.info:eu-repo/semantics/publishedVersio

    Scaffolds based bone tissue engineering : the role of chitosan

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    As life expectancy increases, malfunction or loss of tissue caused by injury or disease leads to reduced quality of life in many patients at significant socioeconomic cost. Even though major progress has been made in the field of bone tissue engineering, present therapies, such as bone grafts, still have limitations. Current research on biodegradable polymers is emerging, combining these structures with osteogenic cells, as an alternative to autologous bone grafts. Different types of biodegradable materials have been proposed for the preparation of three-dimensional porous scaffolds for bone tissue engineering. Among them, natural polymers are one of the most attractive options, mainly due to their similarities with extracellular matrix, chemical versatility, good biological performance, and inherent cellular interactions. In this review, special attention is given to chitosan as a biomaterial for bone tissue engineering applications. An extensive literature survey was performed on the preparation of chitosan scaffolds and their in vitro biological performance as well as their potential to facilitate in vivo bone regeneration. The present review also aims to offer the reader a general overview of all components needed to engineer new bone tissue. It gives a brief background on bone biology, followed by an explanation of all components in bone tissue engineering, as well as describing different tissue engineering strategies. Moreover, also discussed are the typical models used to evaluate in vitro functionality of a tissue-engineered construct and in vivo models to assess the potential to regenerate bone tissue are discussed.Fundação para a Ciência e a Tecnologia (FCT

    Mononeuritis multiplex: an uncommon neurological manifestation of cytomegalovirus reactivation in an HIV-infected patient

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    BACKGROUND: Cytomegalovirus (CMV) reactivation with neurological involvement in patients with acquired immunodeficiency syndrome (AIDS) is increasingly rare since the introduction of antiretroviral therapy (ART). Manifestations include encephalitis, myelitis, polyradiculopathy and, less commonly, mononeuritis multiplex (MNM). We report a case of disseminated CMV disease with gastrointestinal and peripheral and central nervous system involvement in a patient with AIDS, manifesting primarily as MNM. CASE PRESENTATION: A 31-year old woman with AIDS presented with a clinical picture of MNM. Electromyography confirmed the clinical findings. CMV DNA was detected in cerebrospinal fluid (CSF) and blood. Gastrointestinal involvement was histologically documented. HIV RNA was also detected in CSF and brain MRI was consistent with HIV encephalopathy. A diagnosis of disseminated CMV disease (with esophagitis, colitis, encephalitis and MNM) and HIV encephalopathy was made. Treatment consisted of ganciclovir and foscarnet, followed by maintenance therapy with valganciclovir. Evolution was favorable and valganciclovir was stopped after sustained immune recovery following ART initiation. CONCLUSION: We discuss the diagnostic approach to CMV neurological disease, with a focus on MNM and CMV encephalitis. Combination therapy with ganciclovir and foscarnet should be considered for all forms of neurological involvement, although available data are scarce. Since there is significant overlap between CMV encephalitis and HIV encephalopathy, ART drugs with higher CSF penetration may have to be considered. ART and immune recovery are essential to improve outcomes

    Passos para obtenção de leite de cabra com qualidade.

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    Passos para ordenha higiênica; limpeza da sala de ordenha e dos vasilhames.bitstream/CNPGL-2009-09/15847/1/COT135.pd

    Partial safety factors for prestressed concrete girders 2 strengthened with CFRP laminates

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    This paper provides a framework for the calibration of partial safety factors in prestressed concrete (PC) girders strengthened in flexure with carbon fiber-reinforced polymer (CFRP) laminates. A hybrid approach was proposed to take advantage of comprehensive nonlinear numerical models in reliability analysis using a first-order reliability method (FORM) in conjunction with the response surface method (RSM). The PC girders selected for analyses were taken from real structures designed and built in the 1980s based on old standards that now require strengthening and upgrade due to partial corrosion of the prestressing strands. Using the proposed approach, a sensitivity analysis was performed to identify the most relevant variables and assess the area of CFRP laminates needed to restore capacity up to new design standards. A partial safety factor was proposed for strengthening PC girders using CFRP laminates. Sensitivity analysis showed that traffic loads and model uncertainties are the most important variables for calibration. (C) 2019 American Society of Civil Engineers.Portuguese Science and Technology Foundation (FCT)Portuguese Foundation for Science and Technology [SFRH/BD/76345/2011]Australian Research CouncilAustralian Research Council [DE150101703, LP140100591]FCT, within Institute for Sustainability and Innovation in Structural Engineering (ISISE) [UID/ECI/04029/2013]info:eu-repo/semantics/publishedVersio

    Partial safety factors for prestressed concrete girders strengthened with CFRP laminates

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    This paper provides a framework for the calibration of partial safety factors in prestressed concrete (PC) girders strengthened in flexure with carbon fibre-reinforced polymer (CFRP) laminates. A hybrid approach was proposed to take advantage of comprehensive non-linear numerical models in reliability analysis using a first order reliability method (FORM) in conjunction to the response surface method (RSM). The PC girders selected for analyses were taken from real structures designed and built since the 1980s, based on old standards, now requiring strengthening and upgrade due to partial corrosion of prestressing strands. Using the proposed approach, a sensitivity analysis was performed to identify the most relevant variables and assess the area of CFRP laminates needed to restore the capacity to new design standards. Following this study, a partial safety factor was proposed for strengthening PC girders using CFRP laminates. A sensitivity analysis also showed the traffic loads and model uncertainties to be the most important variables for calibration

    Effect of concentration of the diazoalcene molybdenum complex immobilized in ureasil matrix

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    The complex trans-[FMo(NNCHCHCHCH2CH3)(Ph2PCH2CH2PPh2)2][BPh4], was dispersed in a hybrid matrix synthesized by a sol-gel process. The host matrix of the so-called ureasil is a network of silica to which oligopolyoxyethylene chains [POE, (OCH2CH2)n] are grafted by means of urea cross-links. The free complex and sol-gel materials were characterized by thermal analysis (DSC), surface analysis (XPS) and spectroscopic methods (FT-IR and UV/Vis). The data gathered indicates that the molybdenum(IV) complex is immobilized in the host matrix, and it exhibits structural properties different from those of the free form. These differences could arise either from distortions caused by steric effects imposed by the structure of hybrid matrix or by interactions with the matrix. These materials shows potential applications in heterogeneous catalysis in mild conditions

    A novel bioreactor design for enhanced stem cells proliferation and differentiation in tissue engineered constructs

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    [Excerpt] Recent studies have shown that culturing undifferentiated stem cells in appropriate biochemical environments and under mechanical stimulation could provide the correct signals for cellular proliferation, differentiation and subsequent extracellular matrix production. This triggered a growing interest about in vitro biomechanically-stimulating culture environments. [...]info:eu-repo/semantics/publishedVersio

    CMB Constraints on Brane Inflation

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    We investigate the primordial phase of the Universe in the context of brane inflation modeled by Bogomol'nyi-Prasad-Sommerfield (BPS) domain walls solutions of a bosonic sector of a 5D supergravity inspired theory. The solutions are embedded into five dimensions and it is assumed that they interact with each other due to elastic particle collisions in the bulk. A four-dimensional arctan-type inflaton potential drives the accelerated expansion phase and predicts observational quantities in good agreement with the currently available Cosmic Microwave Background data.Comment: 13 pages, 5 figures, 2 tables; typos corrected, one reference adde
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