755 research outputs found

    Microstructure characterisation and mechanical properties of a functionally-graded NbC/high chromium white cast iron composite

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    A functionally graded NbC – high chromium white cast iron composite was successfully fabricated by centrifugal casting for high wear applications. The migration of primary NbC particles to the outer periphery, as predicted by Stokes’ law, resulted in an extremely hard outer layer at the surface of a softer bulk material. Microstructural characterisation showed that both the volume fraction and the morphology of the carbides varies along the thickness of the specimen. At the outer surface, the NbC was present as primary carbides while Chinese-script NbC was found in the bulk of the material. Hardness, sliding wear and three-point bending tests confirmed that the outer layer was harder and more wear resistant than the rest of the material, which was correspondingly tougher. The study of the fracture surface of the specimens showed that there is a strong bond between NbC and the matrix such that delamination between the reinforcements and the matrix did not occur during fracture. If Chinese-script NbC can be reduced or prevented in the bulk material, further improvements to toughness could be achieved.ARC LP130100111, ARC DE150101703, FEDER POCI-01-0145-FEDER-00763

    The Portuguese Severe Asthma Registry: Development, Features, and Data Sharing Policies

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    The Portuguese Severe Asthma Registry (Registo de Asma Grave Portugal, RAG) was developed by an open collaborative network of asthma specialists. RAG collects data from adults and pediatric severe asthma patients that despite treatment optimization and adequate management of comorbidities require step 4/5 treatment according to GINA recommendations. In this paper, we describe the development and implementation of RAG, its features, and data sharing policies. The contents and structure of RAG were defined in a multistep consensus process. A pilot version was pretested and iteratively improved. The selection of data elements for RAG considered other severe asthma registries, aiming at characterizing the patient's clinical status whilst avoiding overloading the standard workflow of the clinical appointment. Features of RAG include automatic assessment of eligibility, easy data input, and exportable data in natural language that can be pasted directly in patients' electronic health record and security features to enable data sharing (among researchers and with other international databases) without compromising patients' confidentiality. RAG is a national web-based disease registry of severe asthma patients, available at asmagrave.pt. It allows prospective clinical data collection, promotes standardized care and collaborative clinical research, and may contribute to inform evidence-based healthcare policies for severe asthma.info:eu-repo/semantics/publishedVersio

    Diagnostic and Therapeutic Approach of Chronic Spontaneous Urticaria: Recommendations in Portugal

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    Chronic spontaneous urticaria is a complex disorder, of unclear etiology, easily diagnosed although often difficult to treat. It has a significant impact on the patients' quality of life and results in high direct and indirect costs. The diagnosis of chronic spontaneous urticaria is mainly clinical and a limited number of tests is recommended for differential diagnosis and/or for the investigation/exclusion of possible causes. In addition to the complete blood count and C-reactive protein, and/or erythrocyte sedimentation rate, additional tests must be selected according to clinical criteria. The aim of therapy is the complete clinical control of chronic spontaneous urticaria. Evolution should be documented by weekly symptom scoring - Weekly Urticaria Activity Score (UAS7) -, as well as the assessment of quality of life. The therapeutic approach is based on second-generation H1 antihistamines (anti-H1) administered continuously in the approved doses (first line), and, in the absence of a clinical response, up to four times the daily-approved dose (second line). First generation H1 antihistamines are not recommended. Approximately 30% of patients are not controlled with second line therapy, and it is recommended to add a third line therapy. Of the two options, omalizumab and cyclosporine, only omalizumab is approved for chronic spontaneous urticaria and has a better safety profile, thus being preferably recommended. In Portugal there are no national-based recommendations applicable to clinical practice. The elaboration of these recommendations is justified by the need to standardize both the diagnosis and the treatment approach of patients with chronic spontaneous urticaria in Portugal, and for the referral of patients to specialized centers, in the most severe cases.info:eu-repo/semantics/publishedVersio

    Chromatin and epigenetics: current biophysical views

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    Recent advances in high-throughput sequencing experiments and their theoretical descriptions have determined fast dynamics of the "chromatin and epigenetics" field, with new concepts appearing at high rate. This field includes but is not limited to the study of DNA-protein-RNA interactions, chromatin packing properties at different scales, regulation of gene expression and protein trafficking in the cell nucleus, binding site search in the crowded chromatin environment and modulation of physical interactions by covalent chemical modifications of the binding partners. The current special issue does not pretend for the full coverage of the field, but it rather aims to capture its development and provide a snapshot of the most recent concepts and approaches. Eighteen open-access articles comprising this issue provide a delicate balance between current theoretical and experimental biophysical approaches to uncover chromatin structure and understand epigenetic regulation, allowing free flow of new ideas and preliminary results

    Convergence of marine megafauna movement patterns in coastal and open oceans

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    Published online February 26, 2018The extent of increasing anthropogenic impacts on large marine vertebrates partly depends on the animals' movement patterns. Effective conservation requires identification of the key drivers of movement including intrinsic properties and extrinsic constraints associated with the dynamic nature of the environments the animals inhabit. However, the relative importance of intrinsic versus extrinsic factors remains elusive. We analyze a global dataset of ∼2.8 million locations from >2,600 tracked individuals across 50 marine vertebrates evolutionarily separated by millions of years and using different locomotion modes (fly, swim, walk/paddle). Strikingly, movement patterns show a remarkable convergence, being strongly conserved across species and independent of body length and mass, despite these traits ranging over 10 orders of magnitude among the species studied. This represents a fundamental difference between marine and terrestrial vertebrates not previously identified, likely linked to the reduced costs of locomotion in water. Movement patterns were primarily explained by the interaction between species-specific traits and the habitat(s) they move through, resulting in complex movement patterns when moving close to coasts compared with more predictable patterns when moving in open oceans. This distinct difference may be associated with greater complexity within coastal microhabitats, highlighting a critical role of preferred habitat in shaping marine vertebrate global movements. Efforts to develop understanding of the characteristics of vertebrate movement should consider the habitat(s) through which they move to identify how movement patterns will alter with forecasted severe ocean changes, such as reduced Arctic sea ice cover, sea level rise, and declining oxygen content.A. M. M. Sequeira ... F. Bailleul ... L. D. Einoder ... S. D. Goldsworthy ... D. Hamer ... A. Lowther, A. Mackay ... J. McKenzie, L. McLeay ... B. Page ... G. B. Skomal ... A. Wiebkin ... et al
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