Search Results - "Prates, S"

Publication Catalog - "Prates, S"

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  1. 1

    In Vitro Methods for Specific IgE Detection on Cow’s Milk Allergy

    Publication
    by Prates, S
    Other Authors: Morais-Almeida, M; Rosado-Pinto, J; Matos, V; Loureiro, V
    Background: A new method for determining serum specific IgE (IMMULITE“ 2000 3gAllergy) has recently become available. Objective: To evaluate the clinical performance of IMMULITE 2000 in the diagnosis of cow’s milk allergy compared with that of UniCAP“. Additionally, we verified the behavior of both methods at two diagnostic decision points proposed by other authors. Methods: The study population consisted of 31 children with cow’s milk allergy (group A) and a control group of 19 atopic children without food allergy(group B). A blood sample from each child was tested using both methods and the results were compared. Results: In group A, the values for cow’s milk IgE ranged from 0.35 kU/L (the lowest common detection limit) to above 100 kU/L. In group B, the values were less than 1.1 kU/L for IMMULITE 2000 and less than 1.6 kU/L for UniCAP. An agreement of 90 % in IgE classes was obtained. Both methods demonstrated exactly the same diagnostic performance(sensitivity: 100 %; specificity: 78.9 %; negative predictive value: 100%; positive predictive value: 84.6%;efficiency: 90.2 %). The evaluation of the two methods at the two different decision points proposed in the literature showed a better positive predictive value with UniCAP, but we obtained equivalent performance with IMMULITE 2000 by choosing higher cutoff values. Conclusions: We conclude that IMMULITE 2000 is as effective as UniCAP in the diagnosis of cow’s milk allergy. Both methods can be used to obtain site-specific decision points that are population, age and disease dependent.
    2006 article Portugal open access
  2. 2

    Limitations of XGBoost in predicting material parameters for complex constitutive models

    Publication
    by Prates, Pedro
    Other Authors: Mitreiro, Dário; Andrade-Campos, António
    Machine learning models, particularly Extreme Gradient Boosting, have been explored for predicting material parameters in constitutive models that describe the plastic behaviour of metal sheets. While effective for simple constitutive models like Hill’48, their performance declines with more complex models such as the Cazacu-Plunckett-Barlat yield criterion. This study examines the influence of training dataset size and dimensionality reduction via principal component analysis on predictive accuracy. Results show that increasing the training dataset size leads to only marginal improvements, with testing coefficient of determination value plateauing at about 0.50, despite a consistently high training value of about 0.99999, indicating overfitting. Similarly, applying principal component analysis to the baseline model provided no significant enhancement. These findings suggest that simply expanding the dataset or reducing dimensionality is insufficient to address the complexities of CPB’06. Instead, alternative approaches such as advanced feature selection, hybrid ML-physics-based models, or regularization techniques may be required to improve generalization. Future work should explore methods integrating domain knowledge and physics-based modelling to enhance predictive accuracy for complex constitutive models.
    2025 article Portugal open access
  3. 3
  4. 4

    Influence of data filtering and noise on the calibration of constitutive models using machine learning techniques

    Publication
    by Prates, Pedro
    Other Authors: Pinto, José; Marques, João; Henriques, João; Pereira, André; Andrade-Campos, António
    This work focuses on predicting material parameters that describe the plastic behaviour of metallic sheets using the XGBoost machine learning algorithm, with a dual focus on the influence of data filtering and data noise. A dataset was populated with finite element simulation results of cruciform tensile tests, including strain field data during the test. Different noise levels were added to the strain-related features of the dataset; additionally, a feature importance study was carried out to identify and select the most relevant features of the dataset. A systematic analysis shows how feature noise and selection individually and simultaneously influence the predictive performance of machine learning models. The results show that feature selection will greatly accelerate model training, without losing its predictive performance. Also, adding noise to the features does not have significant impact on model performance, highlighting the robustness of the models.
    2024 article Portugal open access
  5. 5

    Sobre Dois Casos de Fibroma Ossificante Periférico: Apresentação Clínica e Diagnóstico Diferencial

    Publication
    by Prates, M
    Other Authors: Caixeirinho, P; Machado, MC; Martins, A; Ribeiro, N; Fernandes, F
    2017 other Portugal open access
  6. 6

    First Bite Syndrome: uma Complicação Rara de Cirurgia de Cabeça e Pescoço

    Publication
    by Prates, M
    O First Bite Syndrome é um quadro de dor facial que surge mais frequentemente como complicação de cirurgia da cabeça e pescoço. Caracteriza-se por um quadro de dor que surge com o início da mastigação e que vai diminuindo de intensidade ao longo da refeição. Devido ao impacto que pode ter na alimentação, é importante saber identi%car e tratar esta síndrome. O tratamento pode ser complexo e varia com a causa.
    2019 article Portugal open access
  7. 7

    Infeção da Cavidade Oral Associada a Ventilação Não Invasiva

    Publication
    by Prates, M
    Other Authors: Tavares, AT; Pereira, A; Mussá, Y; Martins, J; Fernandes, F
    2018 other Portugal open access
  8. 8
  9. 9

    Displasia Cimento Óssea Florida: Apresentação Rara de um Problema Comum

    Publication
    by Prates, M
    Other Authors: Zagalo, C; Tavares, AT; Pereira, A; Martins, J; Figueiredo, L
    Introdução A displasia cimento-óssea (DCO) é a lesão fibro-óssea mais comum. Pensa-se que a DCO tem origem no ligamento periodontal. Outros acreditam que tem origem num defeito da remodelação óssea desencadeada por lesões locais. Com base nas características clínicas e radiográficas, as DCO dividem-se em focal, periapical e florida. A DCO florida caracteriza-se por um envolvimento multifocal não limitado aos segmentos anteriores. Esta forma afecta sobretudo mulheres melanodérmicas com particular incidência nos adultos de meia-idade e idosos. Caracteriza-se por lesões bilaterais e por vezes simétricas. Normalmente estas lesões são assintomáticas podendo tratar-se de achados radiográficos. Noutros casos pode haver dor ligeira, fístulas alveolares e exposição óssea. Raramente pode haver expansão óssea. Radiograficamente, apresentam um padrão semelhante às outras formas de DCO. Inicialmente as lesões são radiotransparentes, adquirindo um padrão misto e posteriormente tornam-se radiopacas com halo radiotransparente. Caso Clínico Mulher, 53 anos, originária da Índia, com Diabetes Mellitus tipo 2. Vai a consulta de Cirurgia de Cabeça e Pescoço no IPO Lisboa enviada pelo médico de família com a informação de ser seguida em Oncologia na Índia por “neoplasia óssea com atingimento a nível de mandíbula e maxilar superior com destruição óssea progressiva”. Clinicamente refere desde há 20 anos parestesias na hemimandíbula esquerda com instalação de dor há 10 anos. Com recente irradiação da dor para a nuca. À observação tem gengivite tartárica, sem outras alterações. Traz consigo duas TC-Cone Beam (2012 e 2017) que mostram a existência e evolução de cinco lesões junto às regiões de 13-14, 23-25, 33, 36 e 46. As múltiplas lesões eram sugestivas do diagnóstico de DCO florida. Pediu-se TC Maxilofacial e manteve-se a sob vigilância medicando-se sintomaticamente. Discussão e Conclusões Nas DCO periapical e florida, os achados clínicos e radiográficos permitem fazer um diagnóstico presuntivo. As características da DCO focal são menos específicas e por isso a biopsia pode ser necessária. A DCO não tem natureza neoplásica e geralmente não requer remoção sendo que para um paciente assintomático a reavaliação periódica e o controlo da doença periodontal estão indicados. Raramente, estas lesões apresentam um crescimento progressivo (displasia óssea expansiva) com necessidade de remoção. Em geral, o prognóstico é bom. O desenvolvimento de sarcomas em áreas de DCO está relatado mas é muito raro.
    2019 other Portugal open access
  10. 10

    Oral Infection Caused by Stenotrophomonas maltophilia: A Rare Presentation of an Emerging Opportunistic Pathogen

    Publication
    by Prates, M
    Other Authors: Fernandes, F; Proença, F; Mussá, Y; Tavares, A; Pereira, A
    Stenotrophomonas maltophilia is an emerging multidrug-resistant opportunistic pathogen with an increasing incidence of nosocomial and community-acquired infection cases, mainly in immunocompromised individuals. Oral cavity infections are rare. To learn more about this infection, a case of oral cavity infection caused by S. maltophilia in an immunosuppressed patient under ventilatory therapy has been presented. The patient presented with multiple nonpainful erosive lesions of the tongue, palate, and oral mucosa. A smear of the oral lesions was performed that revealed the presence of S. maltophilia and Candida albicans, and the patient was treated with fluconazole and sulfamethoxazole associated with trimethoprim in accordance with the antimicrobial susceptibility testing. After 14 days of antibiotic therapy, there were almost no signs of the previous lesions.
    2020 article Portugal open access