158 research outputs found

    P-248 Futility and utility of two-stage hepatectomy

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    Meeting abstract in the European-Society-for-Medical-Oncology (ESMO) 21st World Congress on Gastrointestinal Cancer.info:eu-repo/semantics/publishedVersio

    Identification of clinical phenotypes in knee osteoarthritis: a systematic review of the literature

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    Background: Knee Osteoarthritis (KOA) is a heterogeneous pathology characterized by a complex and multifactorial nature. It has been hypothesised that these differences are due to the existence of underlying phenotypes representing different mechanisms of the disease.Methods: The aim of this study is to identify the current evidence for the existence of groups of variables which point towards the existence of distinct clinical phenotypes in the KOA population. A systematic literature search in PubMed was conducted. Only original articles were selected if they aimed to identify phenotypes of patients aged 18 years or older with KOA. The methodological quality of the studies was independently assessed by two reviewers and qualitative synthesis of the evidence was performed. Strong evidence for existence of specific phenotypes was considered present if the phenotype was supported by at least two high-quality studies.Results: A total of 24 studies were included. Through qualitative synthesis of evidence, six main sets of variables proposing the existence of six phenotypes were identified: 1) chronic pain in which central mechanisms (e.g. central sensitisation) are prominent; 2) inflammatory (high levels of inflammatory biomarkers); 3) metabolic syndrome (high prevalence of obesity, diabetes and other metabolic disturbances); 4) Bone and cartilage metabolism (alteration in local tissue metabolism); 5) mechanical overload characterised primarily by varus malalignment and medial compartment disease; and 6) minimal joint disease characterised as minor clinical symptoms with slow progression over time.Conclusions: This study identified six distinct groups of variables which should be explored in attempts to better define clinical phenotypes in the KOA population

    Dynamic models of brain imaging data and their Bayesian inversion

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    This work is about understanding the dynamics of neuronal systems, in particular with respect to brain connectivity. It addresses complex neuronal systems by looking at neuronal interactions and their causal relations. These systems are characterized using a generic approach to dynamical system analysis of brain signals - dynamic causal modelling (DCM). DCM is a technique for inferring directed connectivity among brain regions, which distinguishes between a neuronal and an observation level. DCM is a natural extension of the convolution models used in the standard analysis of neuroimaging data. This thesis develops biologically constrained and plausible models, informed by anatomic and physiological principles. Within this framework, it uses mathematical formalisms of neural mass, mean-field and ensemble dynamic causal models as generative models for observed neuronal activity. These models allow for the evaluation of intrinsic neuronal connections and high-order statistics of neuronal states, using Bayesian estimation and inference. Critically it employs Bayesian model selection (BMS) to discover the best among several equally plausible models. In the first part of this thesis, a two-state DCM for functional magnetic resonance imaging (fMRI) is described, where each region can model selective changes in both extrinsic and intrinsic connectivity. The second part is concerned with how the sigmoid activation function of neural-mass models (NMM) can be understood in terms of the variance or dispersion of neuronal states. The third part presents a mean-field model (MFM) for neuronal dynamics as observed with magneto- and electroencephalographic data (M/EEG). In the final part, the MFM is used as a generative model in a DCM for M/EEG and compared to the NMM using Bayesian model selection

    Polyhydroxyalkanoates Production by Mixed Microbial Culture under High Salinity

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    PTDC/BTA-BTA/30902/2017 UIDP/04378/2020 UIDB/04378/2020 LA/P/0140/2020The fishing industry produces vast amounts of saline organic side streams that require adequate treatment and disposal. The bioconversion of saline resources into value-added products, such as biodegradable polyhydroxyalkanoates (PHAs), has not yet been fully explored. This study investigated PHA production by mixed microbial cultures under 30 gNaCl/L, the highest NaCl concentration reported for the acclimatization of a PHA-accumulating mixed microbial culture (MMC). The operational conditions used during the culture-selection stage resulted in an enriched PHA-accumulating culture dominated by the Rhodobacteraceae family (95.2%) and capable of storing PHAs up to 84.1% wt. (volatile suspended solids (VSS) basis) for the highest organic loading rate (OLR) applied (120 Cmmol/(L.d)). This culture presented a higher preference for the consumption of valeric acid (0.23 ± 0.03 CmolHVal/(CmolX.h)), and the 3HV monomer polymerization (0.33 ± 0.04 CmmolHV/(CmmolX.h) was higher as well. As result, a P(3HB-co-3HV)) with high HV content (63% wt.) was produced in the accumulation tests conducted at higher OLRs and with 30 gNaCl/L. A global volumetric PHA productivity of 0.77 gPHA/(L.h) and a specific PHA productivity of 0.21 gPHA/(gX.h) were achieved. These results suggested the significant potential of the bioconversion of saline resources into value-added products, such as PHAs.publishersversionpublishe

    Pontine and Extrapontine Myelinolysis

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    Introdução: A mielinólise define-se como uma doença desmielinizante aguda, associada a um quadro clínico de tetraplegia flácida e a incapacidade na fala e na deglutição. A patogenia em geral está associada a perturbações electrolíticas, particularmente hiponatrémia profunda e sua rápida correcção. A confirmação imagiológica do diagnóstico pode ser feita recorrendo à Ressonância Magnética Nuclear. Objectivo: Os autores fazem a descrição do caso clínico, evidenciando a sua evolução e programa de reabilitação instituído, realçando os ganhos da funcionalidade. São descritas também as intercorrências clínicas relevantes no atraso do diagnóstico. Caso clínico: Apresenta-se uma doente com antecedentes psiquiátricos e polidipsia, internada na sequência de um quadro convulsivo resistente à medicação, tendo sido identificada hiponatrémia e feita a sua correcção. Após a correcção a doente desenvolveu um quadro de tetraplegia e hipotonia generalizada, tendo realizado uma Ressonância Magnética compatível com o diagnóstico de mielinólise centropôntica e extrapôntica

    Data-driven approach for incident management in a smart city

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    Buildings in Lisbon are often the victim of several types of events (such as accidents, fires, collapses, etc.). This study aims to apply a data-driven approach towards knowledge extraction from past incident data, nowadays available in the context of a Smart City. We apply a Cross Industry Standard Process for Data Mining (CRISP-DM) approach to perform incident management of the city of Lisbon. From this data-driven process, a descriptive and predictive analysis of an events dataset provided by the Lisbon Municipality was possible, together with other data obtained from the public domain, such as the temperature and humidity on the day of the events. The dataset provided contains events from 2011 to 2018 for the municipality of Lisbon. This data mining approach over past data identified patterns that provide useful knowledge for city incident managers. Additionally, the forecasts can be used for better city planning, and data correlations of variables can provide information about the most important variables towards those incidents. This approach is fundamental in the context of smart cities, where sensors and data can be used to improve citizens’ quality of life. Smart Cities allow the collecting of data from different systems, and for the case of disruptive events, these data allow us to understand them and their cascading effects better.info:eu-repo/semantics/publishedVersio

    Portuguese Cucurbita spp. and Citrullus lanatus: conservation, evaluation and breeding

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    Cucurbitaceae is one of the most important families of vascular plants. This family includes 118 genera and 825 species. The five major cucurbit crops are Citrullus lanatus Thumb Mansf. (watermelon), Cucurbita maxima Duchesne (pumpkin), Cucurbita pepo L. (squash), Cucumis sativus L. (cucumber) and Cucumis melo L. (melon). Citrullus lanatus and Cucurbita spp. are very important in the Portuguese agro-ecosystems, associated with maize, beans and cabbage. Due to the importance of Citrullus and Cucurbita spp., the Portuguese National Genebank (BPGV) has done systematic collecting missions in Portugal (Mainland and Madeira Island). Since 2001, BPGV in partnership with other National Institutions, Escola Superior Agraria de Santarem, Direccao Regional de Agricultura e Pescas do Algarve and Universidade do Algarve, has been carrying out activities related to preservation, characterization, evaluation and pre-breeding. In Portugal, in BPGV, the Curcubitaceae collection preserved in ex situ conditions (medium and long term) totals 573 accessions. The collection of Citrullus lanatus and Cucurbita spp. has a total of 355 accessions, representing 62% of the whole collection: (37 of Citrullus lanatus, 19 of Cucurbita ficifolia, 74 of Cucurbita maxima and 224 of Cucurbita pepo). Based upon the diagnosis of the preserved collection, further germplasm collecting missions were recommended in Algarve Region. AFLP and RAPDs markers were used to check the assignment of accessions to Cucurbita species: C. pepo, C. maxima and C. moshata. The morphological characterization followed the Curcubita spp. and Citrullus descriptors, elaborated by Bioversity International, integrated in the European Cooperative Program for Genetic Resources, Cucurbits Working Group. Characterization data are reported herein. Departing from the most homogeneous accessions of Citrullus lanatus, Cucurbita maxima and C. moschata, three cultivars, one of each species, have already been selected and registered in the National Catalogue of Varieties

    Mechanisms explaining transitions between tonic and phasic firing in neuronal populations as predicted by a low dimensional firing rate model

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    Several firing patterns experimentally observed in neural populations have been successfully correlated to animal behavior. Population bursting, hereby regarded as a period of high firing rate followed by a period of quiescence, is typically observed in groups of neurons during behavior. Biophysical membrane-potential models of single cell bursting involve at least three equations. Extending such models to study the collective behavior of neural populations involves thousands of equations and can be very expensive computationally. For this reason, low dimensional population models that capture biophysical aspects of networks are needed. \noindent The present paper uses a firing-rate model to study mechanisms that trigger and stop transitions between tonic and phasic population firing. These mechanisms are captured through a two-dimensional system, which can potentially be extended to include interactions between different areas of the nervous system with a small number of equations. The typical behavior of midbrain dopaminergic neurons in the rodent is used as an example to illustrate and interpret our results. \noindent The model presented here can be used as a building block to study interactions between networks of neurons. This theoretical approach may help contextualize and understand the factors involved in regulating burst firing in populations and how it may modulate distinct aspects of behavior.Comment: 25 pages (including references and appendices); 12 figures uploaded as separate file

    Spina bifida-predisposing heterozygous mutations in Planar Cell Polarity genes and Zic2 reduce bone mass in young mice

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    Fractures are a common comorbidity in children with the neural tube defect (NTD) spina bifida. Mutations in the Wnt/planar cell polarity (PCP) pathway contribute to NTDs in humans and mice, but whether this pathway independently determines bone mass is poorly understood. Here, we first confirmed that core Wnt/PCP components are expressed in osteoblasts and osteoclasts in vitro. In vivo, we performed detailed µCT comparisons of bone structure in tibiae from young male mice heterozygous for NTD-associated mutations versus WT littermates. PCP signalling disruption caused by Vangl2 (Vangl2Lp/+) or Celsr1 (Celsr1Crsh/+) mutations significantly reduced trabecular bone mass and distal tibial cortical thickness. NTD-associated mutations in non-PCP transcription factors were also investigated. Pax3 mutation (Pax3Sp2H/+) had minimal effects on bone mass. Zic2 mutation (Zic2Ku/+) significantly altered the position of the tibia/fibula junction and diminished cortical bone in the proximal tibia. Beyond these genes, we bioinformatically documented the known extent of shared genetic networks between NTDs and bone properties. 46 genes involved in neural tube closure are annotated with bone-related ontologies. These findings document shared genetic networks between spina bifida risk and bone structure, including PCP components and Zic2. Genetic variants which predispose to spina bifida may therefore independently diminish bone mass
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