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1.
Ultrason Imaging ; 46(1): 3-16, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38041411

RESUMO

Thermal treatments that use ultrasound devices as a tool have as a key point the temperature control to be applied in a specific region of the patient's body. This kind of procedure requires caution because the wrong regulation can either limit the treatment or aggravate an existing injury. Therefore, determining the temperature in a region of interest in real-time is a subject of high interest. Although this is still an open problem, in the field of ultrasound analysis, the use of machine learning as a tool for both imaging and automated diagnostics are application trends. In this work, a data-driven approach is proposed to address the problem of estimating the temperature in regions of a B-mode ultrasound image as a supervised learning problem. The proposal consists in presenting a novel data modeling for the problem that includes information retrieved from conventional B-mode ultrasound images and a parametric image built based on changes in backscattered energy (CBE). Then, we compare the performance of classic models in the literature. The computational results presented that, in a simulated scenario, the proposed approach that a Gradient Boosting model would be able to estimate the temperature with a mean absolute error of around 0.5°C, which is acceptable in practical environments both in physiotherapic treatments and high intensity focused ultrasound (HIFU).


Assuntos
Temperatura , Humanos , Ultrassonografia/métodos
2.
Int J Mol Sci ; 24(12)2023 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-37373079

RESUMO

The systemic increase in inflammatory mediator levels can induce diverse pathological disorders, including potentially thrombus formation, which may be lethal. Among the clinical conditions in which the formation of thrombi dictates the patient's prognosis, envenomation by Bothrops lanceolatus should be emphasized, as it can evolve to stroke, myocardial infarction and pulmonary embolism. Despite their life-threatening potential, the immunopathological events and toxins involved in these reactions remain poorly explored. Therefore, in the present study, we examined the immunopathological events triggered by a PLA2 purified from B. lanceolatus venom, using an ex vivo human blood model of inflammation. Our results showed that the purified PLA2 from the venom of B. lanceolatus damages human erythrocytes in a dose dependent way. The cell injury was associated with a decrease in the levels of CD55 and CD59 complement regulators on the cell surface. Moreover, the generation of anaphylatoxins (C3a and C5a) and the soluble terminal complement complex (sTCC) indicates that human blood exposure to the toxin activates the complement system. Increased production of TNF-α, CXCL8, CCL2 and CCL5 followed complement activation. The venom PLA2 also triggered the generation of lipid mediators, as evidenced by the detected high levels of LTB4, PGE2 and TXB2. The scenario here observed of red blood cell damage, dysfunctions of the complement regulatory proteins, accompanied by an inflammatory mediator storm, suggests that B. lanceolatus venom PLA2 contributes to the thrombotic disorders present in the envenomed individuals.


Assuntos
Bothrops , Mordeduras de Serpentes , Toxinas Biológicas , Animais , Humanos , Proteínas do Sistema Complemento , Fosfolipases A2 , Venenos de Serpentes/toxicidade
3.
BrJP ; 6(2): 151-159, Apr.-June 2023. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1513778

RESUMO

ABSTRACT BACKGROUND AND OBJECTIVES: Despite the widespread use of mid-frequency currents in reducing pain in chronic low back pain (CLBP), there is still no consensus on the optimal parameters for treatment. The aim of this study was to compare the immediate analgesic effects of interferential (IC) and Aussie (AC) currents in CLBP. METHODS: This is a five-arm double-blind randomized controlled trial. Patients aged between 18 and 60 years with CLBP were randomly divided into 5 groups: CI4kHz/100Hz, CI4kHz/2Hz, CA4kHz/100Hz, CA4kHz/2Hz and placebo (PG). Participants received a single application of Interferential current or Aussie current for 30 min. Main outcome measures were pain intensity by numeric pain scale (NPS), McGill pain questionnaire (MPQ) and pressure pain threshold. The secondary outcomes assessed were: abdominal strength test (AST), lumbar flexion test (modified Schober test), trunk and lower limb mobility (sit and reach test and finger tip test). RESULTS: There was a significant difference in NPS and MPQ groups (with the exception of the affective component) (p<0.05) in IC 4 kHz/100 Hz and IC 4 kHz/2 Hz groups in relation to PG. Regarding secondary outcomes, a difference was found only between IC 4kHz/2Hz and PG in AET. CONCLUSION: Interferential current, regardless of frequency modulation, provided immediate analgesic effect in individuals with CLBP, being superior to the effects of Aussie current.


RESUMO JUSTIFICATIVA E OBJETIVOS: Apesar da grande utilização das correntes de média frequência na diminuição do quadro álgico na dor lombar crônica (DLC), ainda não existe consenso sobre os parâmetros ideais para tratamento. O objetivo deste estudo foi comparar os efeitos analgésicos imediatos das correntes interferencial (CI) e Aussie (CA) na DLC. MÉTODOS: Trata-se de um ensaio clínico randomizado controlado duplo-cego de cinco braços. Foram selecionados pacientes com idades entre 18 e 60 anos, com DLC, que foram divididos aleatoriamente em 5 grupos: CI4kHz/100Hz, CI4kHz/2Hz, CA4kHz/100Hz, CA4kHz/2Hz e placebo (GP). Os participantes receberam uma única aplicação da corrente Interferencial ou corrente Aussie durante 30 min. As principais medidas de desfechos foram: intensidade da dor pela escala numérica da dor (END), questionário de dor McGill (QDM) e limiar de dor por pressão. Os desfechos secundários avaliados foram: teste de resistência abdominal (TRA), teste de flexão da lombar (teste de Schober modificado), mobilidade de tronco e membros inferiores (teste de sentar e alcançar e teste de distância do terceiro dedo ao solo). RESULTADOS: Houve diferença significativa nos grupos END e QDM (com exceção do componente afetivo) (p<0,05) nos grupos CI 4 kHz/100 Hz e CI 4 kHz/2 Hz em relação ao GP. Com relação aos desfechos secundários foi encontrada diferença somente entre CI 4kHz/2Hz e GP no TRA. CONCLUSÃO: A corrente interferencial, independente da modulação da frequência, proporcionou efeito analgésico imediato em indivíduos com DLC, sendo superior aos efeitos da corrente Aussie.

4.
Front Immunol ; 14: 1125899, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37006255

RESUMO

Snake venom enzymes have a broad range of molecular targets in plasma, tissues, and cells, among which hyaluronan (HA) is outstanding. HA is encountered in the extracellular matrix of diverse tissues and in the bloodstream, and its different chemical configurations dictate the diverse morphophysiological processes in which it participates. Hyaluronidases are highlighted among the enzymes involved in HA metabolism. This enzyme has been detected along the phylogenetic tree, suggesting that hyaluronidases exert multiple biological effects on different organisms. Hyaluronidases have been described in tissues, blood and snake venoms. Snake venom hyaluronidases (SVHYA) contribute to tissue destruction in envenomations and are called spreading factors since their action potentiates venom toxin delivery. Interestingly, SVHYA are clustered in Enzyme Class 3.2.1.35 together with mammalian hyaluronidases (HYAL). Both HYAL and SVHYA of Class 3.2.1.35 act upon HA, generating low molecular weight HA fragments (LMW-HA). LMW-HA generated by HYAL becomes a damage-associated molecular pattern that is recognized by Toll-like receptors 2 and 4, triggering cell signaling cascades culminating in innate and adaptive immune responses that are characterized by lipid mediator generation, interleukin production, chemokine upregulation, dendritic cell activation and T cell proliferation. In this review, aspects of the structures and functions of HA and hyaluronidases in both snake venoms and mammals are presented, and their activities are compared. In addition, the potential immunopathological consequences of HA degradation products generated after snakebite envenoming and their use as adjuvant to enhance venom toxin immunogenicity for antivenom production as well as envenomation prognostic biomarker are also discussed.


Assuntos
Hialuronoglucosaminidase , Toxinas Biológicas , Animais , Hialuronoglucosaminidase/metabolismo , Ácido Hialurônico/metabolismo , Filogenia , Venenos de Serpentes , Mamíferos/metabolismo
5.
Front Immunol ; 12: 652242, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33936074

RESUMO

Systemic complement activation drives a plethora of pathological conditions, but its role in snake envenoming remains obscure. Here, we explored complement's contribution to the physiopathogenesis of Naja annulifera envenomation. We found that N. annulifera venom promoted the generation of C3a, C4a, C5a, and the soluble Terminal Complement Complex (sTCC) mediated by the action of snake venom metalloproteinases. N. annulifera venom also induced the release of lipid mediators and chemokines in a human whole-blood model. This release was complement-mediated, since C3/C3b and C5a Receptor 1 (C5aR1) inhibition mitigated the effects. In an experimental BALB/c mouse model of envenomation, N. annulifera venom promoted lipid mediator and chemokine production, neutrophil influx, and swelling at the injection site in a C5a-C5aR1 axis-dependent manner. N. annulifera venom induced systemic complementopathy and increased interleukin and chemokine production, leukocytosis, and acute lung injury (ALI). Inhibition of C5aR1 with the cyclic peptide antagonist PMX205 rescued mice from these systemic reactions and abrogated ALI development. These data reveal hitherto unrecognized roles for complement in envenomation physiopathogenesis, making complement an interesting therapeutic target in envenomation by N. annulifera and possibly by other snake venoms.


Assuntos
Ativação do Complemento/imunologia , Complemento C5a/imunologia , Complemento C5a/metabolismo , Receptor da Anafilatoxina C5a/metabolismo , Venenos de Serpentes/imunologia , Animais , Biomarcadores , Quimiocinas/metabolismo , Modelos Animais de Doenças , Humanos , Hidrólise , Inflamação/etiologia , Inflamação/metabolismo , Inflamação/patologia , Mediadores da Inflamação/metabolismo , Masculino , Camundongos , Modelos Biológicos , Naja , Ligação Proteica , Transdução de Sinais , Mordeduras de Serpentes
6.
Psicol. teor. prát ; 23(1): 1-21, Jan.-Apr. 2021. ilus
Artigo em Inglês, Português | LILACS, Index Psicologia - Periódicos | ID: biblio-1250544

RESUMO

Higher education is replete with considerable changes, challenges, and novel situations for many Brazilian youths entering college. This study's objective was to translate, adapt, and verify the content validity and internal consistency of the Perceptions of Academic Stress Scale to measure university students' perceptions regarding academic stress and its sources. The study was performed in two stages. The first comprised the instrument's translation, adaptation, and content validity, and the second consisted of an assessment of its internal consistency. Both stages presented satisfactory results, with a strong inter-rater agreement and acceptable internal consistency measures. The verification of the content validity and the reliability of the PAS Scale for the Brazilian context resulted in an instrument with appropriate and relevant psychometric parameters.


Para muitos jovens brasileiros que ingressam na graduação, o ensino superior é um momento de enormes mudanças, desafios e novidades. Este estudo teve como objetivo traduzir, adaptar, verificar a validade de conteúdo e consistência interna da Perceptions of Academic Stress Scale, que avalia a percepção dos estudantes universitários a respeito do estresse acadêmico e suas fontes. O estudo foi desenvolvido em duas fases: na primeira, foi realizada a tradução, adaptação e validação de conteúdo da escala; na segunda, a avaliação da consistência interna. As duas fases do estudo geraram resultados satisfatórios, por meio de concordância forte entre os especialistas e medidas de consistência interna aceitáveis. O processo de verificação da validade de conteúdo e confiabilidade do PAS Scale para o Brasil disponibilizou um instrumento com parâmetros psicométricos adequados e pertinentes.


Para muchos jóvenes brasileños que ingresan en una carrera universitaria, la enseñanza académica es un momento de enormes cambios, desafíos y novedades. Este estudio tuvo como objetivo traducir, adaptar, verificar la validad de contenido y consistencia interna del Perceptions of Academic Stress Scale, que evalúa la percepción de los estudiantes universitarios respecto al estrés académico y sus orígenes. El estudio fue desarrollado en dos etapas: en la primera fue realizada la traducción, adaptación y validación del contenido de la escala; en la segunda, la evaluación de la consistencia interna. Ambas fases del estudio generaron resultados satisfactorios, con un fuerte acuerdo entre los expertos y evidencia de confiabilidad través de una consistencia interna aceptable. El proceso de verificación de la validez de contenido y confiabilidad del PAS Scale para Brasil hizo disponible un instrumento con parámetros psicométricos adecuados y pertinentes.


Assuntos
Humanos , Estresse Psicológico , Estudantes , Universidades , Percepção , Psicometria , Ensino , Tradução , Reprodutibilidade dos Testes , Confiabilidade dos Dados
7.
J Med Primatol ; 50(2): 138-140, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33598919

RESUMO

In a captive Macaca mulatta breeding colony, a single family group with 39 animals showed 19 individuals being born with dramatic tail shortening. Through clinical, genealogical, radiographic, and cytogenetic evaluation, it was related to a probable dominant autosomal inheritance of the reduction in the number of distal caudal vertebrae.


Assuntos
Macaca mulatta/anormalidades , Doenças dos Macacos/congênito , Cauda/anormalidades , Animais , Animais de Laboratório/anormalidades , Feminino , Masculino , Cauda/anatomia & histologia
8.
Arch Toxicol ; 95(3): 1129-1138, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33398417

RESUMO

Systemic increased inflammatory mediators' levels are a hallmark in a plethora of pathological conditions, including thrombotic diseases as the envenomation by Bothrops lanceolatus snake. Multiple organ infarctions, which are not prevented by anticoagulant therapy, are the main cause of death on this envenomation. However, the potential mechanisms involved in these systemic reactions are underexplored. This study aimed to explore the potential systemic events which could contribute to thrombotic reactions on the envenomation by B. lanceolatus in an ex vivo human whole-blood model. B. lanceolatus venom elicited an inflammatory reaction, which was characterized by a strong complement activation, since we detected high C3a, C4a and C5a anaphylatoxins levels. Besides, the venom promoted soluble Terminal Complement Complex (sTCC) assembly. Complement activation was accompanied by intense lipid mediators' release, which included LTB4, PGE2 and TXB2. In addition, in the blood exposed to B. lanceolatus venom, we detected IL-1ß, IL-6 and TNF-α interleukins production. Chemokines, including CCL2, CCL5 and CXCL8 were upregulated in the venom presence. These outcomes show that B. lanceolatus venom causes a strong inflammatory reaction in the blood favoring a potential setting to thrombi formation. Thus, inhibiting inflammatory mediators or their receptors may help in the envenomed patients' management.


Assuntos
Bothrops , Venenos de Crotalídeos/toxicidade , Mediadores da Inflamação/metabolismo , Inflamação/etiologia , Animais , Humanos , Inflamação/patologia , Mediadores da Inflamação/sangue , Trombose/etiologia , Trombose/patologia
9.
PLoS Negl Trop Dis ; 13(1): e0007017, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30657756

RESUMO

BACKGROUND: Naja annulifera is a medically important venomous snake occurring in some of the countries in Sub-Saharan Africa. Accidental bites result in severe coagulation disturbances, systemic inflammation and heart damage, as reported in dogs, and death, by respiratory arrest, in humans. Despite the medical importance of N. annulifera, little is known about its venom composition and the pathogenesis of envenomation. In this paper, the toxic, inflammatory and immunogenic properties of N. annulifera venom were analyzed. METHODOLOGY/PRINCIPAL FINDINGS: Venom proteomic analysis identified 79 different proteins, including Three Finger Toxins, Cysteine Rich Secretory Proteins, Metalloproteinases, Phospholipases A2 (PLA2), Hyaluronidase, L-amino-acid oxidase, Cobra Venom Factor and Serine Proteinase. The presence of PLA2, hyaluronidase, fibrinogenolytic and anticoagulant activities was detected using functional assays. The venom was cytotoxic to human keratinocytes. In an experimental murine model of envenomation, it was found that the venom induced local changes, such as swelling, which was controlled by anti-inflammatory drugs. Moreover, the venom caused death, which was preceded by systemic inflammation and pulmonary hemorrhage. The venom was shown to be immunogenic, inducing a strong humoral immune response, with the production of antibodies able to recognize venom components with high molecular weight and to neutralize its lethal activity. CONCLUSIONS/SIGNIFICANCE: The results obtained in this study demonstrate that N. annulifera venom contains toxins able to induce local and systemic inflammation, which can contribute to lung damage and death. Moreover, the venom is immunogenic, an important feature that must be considered during the production of a therapeutic anti-N. annulifera antivenom.


Assuntos
Venenos Elapídicos/análise , Venenos Elapídicos/toxicidade , Animais , Antivenenos/farmacologia , Feminino , Hialuronoglucosaminidase/análise , L-Aminoácido Oxidase/análise , Masculino , Metaloproteases/análise , Camundongos , Camundongos Endogâmicos BALB C , Naja , Fosfolipases A2/análise , Proteômica , Serina Proteases/análise
10.
Neural Comput ; 31(1): 176-207, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30462587

RESUMO

The Wilkie, Stonham, and Aleksander recognition device (WiSARD) n -tuple classifier is a multiclass weightless neural network capable of learning a given pattern in a single step. Its architecture is determined by the number of classes it should discriminate. A target class is represented by a structure called a discriminator, which is composed of N RAM nodes, each of them addressed by an n -tuple. Previous studies were carried out in order to mitigate an important problem of the WiSARD n -tuple classifier: having its RAM nodes saturated when trained by a large data set. Finding the VC dimension of the WiSARD n -tuple classifier was one of those studies. Although no exact value was found, tight bounds were discovered. Later, the bleaching technique was proposed as a means to avoid saturation. Recent empirical results with the bleaching extension showed that the WiSARD n -tuple classifier can achieve high accuracies with low variance in a great range of tasks. Theoretical studies had not been conducted with that extension previously. This work presents the exact VC dimension of the basic two-class WiSARD n -tuple classifier, which is linearly proportional to the number of RAM nodes belonging to a discriminator, and exponentially to their addressing tuple length, precisely N(2n-1)+1 . The exact VC dimension of the bleaching extension to the WiSARD n -tuple classifier, whose value is the same as that of the basic model, is also produced. Such a result confirms that the bleaching technique is indeed an enhancement to the basic WiSARD n -tuple classifier as it does no harm to the generalization capability of the original paradigm.

11.
Front Neurosci ; 12: 791, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30443204

RESUMO

Imagery of facial expressions in Autism Spectrum Disorder (ASD) is likely impaired but has been very difficult to capture at a neurophysiological level. We developed an approach that allowed to directly link observation of emotional expressions and imagery in ASD, and to derive biomarkers that are able to classify abnormal imagery in ASD. To provide a handle between perception and action imagery cycles it is important to use visual stimuli exploring the dynamical nature of emotion representation. We conducted a case-control study providing a link between both visualization and mental imagery of dynamic facial expressions and investigated source responses to pure face-expression contrasts. We were able to replicate the same highly group discriminative neural signatures during action observation (dynamical face expressions) and imagery, in the precuneus. Larger activation in regions involved in imagery for the ASD group suggests that this effect is compensatory. We conducted a machine learning procedure to automatically identify these group differences, based on the EEG activity during mental imagery of facial expressions. We compared two classifiers and achieved an accuracy of 81% using 15 features (both linear and non-linear) of the signal from theta, high-beta and gamma bands extracted from right-parietal locations (matching the precuneus region), further confirming the findings regarding standard statistical analysis. This robust classification of signals resulting from imagery of dynamical expressions in ASD is surprising because it far and significantly exceeds the good classification already achieved with observation of neutral face expressions (74%). This novel neural correlate of emotional imagery in autism could potentially serve as a clinical interventional target for studies designed to improve facial expression recognition, or at least as an intervention biomarker.

12.
Toxicon ; 148: 85-94, 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29673703

RESUMO

Snakebite is a public health problem in many countries of world. These accidents are considered a Neglected Tropical Disease and are responsible for a high morbidity and mortality index in the South and Southeast Asia and Sub-Saharan Africa. Angolan snake venoms are poorly investigated and no specific antivenom against them is available in the country. Thus, the aim of this study was to evaluate biochemical and immunogenic properties of male and female venoms from Naja nigricollis, Bitis arietans and Bitis gabonica snakes. These animals were collected during an expedition covering 1350 km of Angola, including the Provinces of Cuanza Sul, Benguela, Huíla and Malanje. Results showed that Angolan snake venoms present distinctive immunogenic properties and large intra-specific variations, associated to the gender and the geographic origin of the animals. Thus, it is possible to suggest that for the preparation of a therapeutic antivenom, intra-species variability should be taken into account, in order to obtain an efficient serum to neutralize the toxic effects of the Angolan snake venoms.


Assuntos
Venenos Elapídicos/química , Venenos Elapídicos/imunologia , Venenos de Víboras/química , Venenos de Víboras/imunologia , Angola , Animais , Venenos Elapídicos/enzimologia , Eletroforese , Feminino , Masculino , Camundongos , Naja , Doenças Negligenciadas , Fatores Sexuais , Mordeduras de Serpentes , Especificidade da Espécie , Venenos de Víboras/enzimologia , Viperidae
13.
Neural Netw ; 91: 85-101, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28500895

RESUMO

In the last decade, given the availability of corpora in several distinct languages, research on multilingual part-of-speech tagging started to grow. Amongst the novelties there is mWANN-Tagger (multilingual weightless artificial neural network tagger), a weightless neural part-of-speech tagger capable of being used for mostly-suffix-oriented languages. The tagger was subjected to corpora in eight languages of quite distinct natures and had a remarkable accuracy with very low sample deviation in every one of them, indicating the robustness of weightless neural systems for part-of-speech tagging tasks. However, mWANN-Tagger needed to be tuned for every new corpus, since each one required a different parameter configuration. For mWANN-Tagger to be truly multilingual, it should be usable for any new language with no need of parameter tuning. This article proposes a study that aims to find a relation between the lexical diversity of a language and the parameter configuration that would produce the best performing mWANN-Tagger instance. Preliminary analyses suggested that a single parameter configuration may be applied to the eight aforementioned languages. The mWANN-Tagger instance produced by this configuration was as accurate as the language-dependent ones obtained through tuning. Afterwards, the weightless neural tagger was further subjected to new corpora in languages that range from very isolating to polysynthetic ones. The best performing instances of mWANN-Tagger are again the ones produced by the universal parameter configuration. Hence, mWANN-Tagger can be applied to new corpora with no need of parameter tuning, making it a universal multilingual part-of-speech tagger. Further experiments with Universal Dependencies treebanks reveal that mWANN-Tagger may be extended and that it has potential to outperform most state-of-the-art part-of-speech taggers if better word representations are provided.


Assuntos
Linguística/métodos , Processamento de Linguagem Natural , Redes Neurais de Computação
14.
J. vasc. bras ; 15(3): 245-249, jul.-set. 2016. graf
Artigo em Português | LILACS | ID: lil-797956

RESUMO

Resumo A doença cística da adventícia é uma entidade rara que acomete principalmente a artéria poplítea. A ocorrência em veias é muito rara, e sua etiologia é desconhecida. Clinicamente, apresenta-se como isquemia, trombose ou dor a depender do território acometido. Apresentamos o caso de um paciente masculino jovem referindo nódulo no braço esquerdo. A angiorressonância magnética do membro mostrou lesão cística em contato com a veia basílica, com conteúdo homogêneo e sem realce pós-contraste. Foi realizada ressecção da lesão em bloco com o segmento venoso envolvido. O estudo anatomopatológico foi sugestivo de cisto de adventícia de veia basílica.


Abstract Cystic adventitial disease is a rare entity that most often involves the popliteal artery. It rarely occurs in veins. Its etiology is unknown. Clinically, it presents with ischemia, thrombosis or pain, depending on the vessel affected. Here we present the case of a young male with a nodule in the left arm. Magnetic resonance angiography showed a cystic lesion in contact with the basilic vein, with homogenous content without post-contrast enhancement. The lesion was resected en bloc together with the venous segment involved. The results of microscopic analysis were suggestive of basilic vein cystic adventitial disease.


Assuntos
Humanos , Masculino , Adulto , Cisto Epidérmico/diagnóstico por imagem , Artéria Poplítea/anatomia & histologia , Artéria Poplítea/diagnóstico por imagem
16.
Neural Netw ; 66: 11-21, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25795509

RESUMO

Training part-of-speech taggers (POS-taggers) requires iterative time-consuming convergence-dependable steps, which involve either expectation maximization or weight balancing processes, depending on whether the tagger uses stochastic or neural approaches, respectively. Due to the complexity of these steps, multilingual part-of-speech tagging can be an intractable task, where as the number of languages increases so does the time demanded by these steps. WiSARD (Wilkie, Stonham and Aleksander's Recognition Device), a weightless artificial neural network architecture that proved to be both robust and efficient in classification tasks, has been previously used in order to turn the training phase faster. WiSARD is a RAM-based system that requires only one memory writing operation to train each sentence. Additionally, the mechanism is capable of learning new tagged sentences during the classification phase, on an incremental basis. Nevertheless, parameters such as RAM size, context window, and probability bit mapping, make the multilingual part-of-speech tagging task hard. This article proposes mWANN-Tagger (multilingual Weightless Artificial Neural Network tagger), a WiSARD POS-tagger. This tagger is proposed due to its one-pass learning capability. It allows language-specific parameter configurations to be thoroughly searched in quite an agile fashion. Experimental evaluation indicates that mWANN-Tagger either outperforms or matches state-of-art methods in accuracy with very low standard deviation, i.e., lower than 0.25%. Experimental results also suggest that the vast majority of the languages can benefit from this architecture.


Assuntos
Linguística/métodos , Redes Neurais de Computação , Processamento de Linguagem Natural
17.
Annu Int Conf IEEE Eng Med Biol Soc ; 2015: 4470-4, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26737287

RESUMO

This work introduces a new methodology for the early detection of epileptic seizure based on the WiSARD weightless neural network model and a new approach in terms of preprocessing the electroencephalogram (EEG) data. WiSARD has, among other advantages, the capacity of perform the training phase in a very fast way. This speed in training is due to the fact that WiSARD's neurons work like Random Access Memories (RAM) addressed by input patterns. Promising results were obtained in the anticipation of seizure onsets in four representative patients from the European Database on Epilepsy (EPILEPSIAE). The proposed seizure early detection WNN architecture was explored by varying the detection anticipation (δ) in the 2 to 30 seconds interval, and by adopting 2 and 3 seconds as the width of the Sliding Observation Window (SOW) input. While in the most challenging patient (A) one obtained accuracies from 99.57% (δ=2s; SOW=3s) to 72.56% (δ=30s; SOW=2s), patient D seizures could be detected in the 99.77% (δ=2s; SOW=2s) to 99.93% (δ=30s; SOW=3s) accuracy interval.


Assuntos
Epilepsia , Diagnóstico Precoce , Eletroencefalografia , Humanos , Redes Neurais de Computação , Convulsões
18.
Ann Thorac Surg ; 97(5): 1750-6; discussion 1756-7, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24612704

RESUMO

BACKGROUND: Thoracic surgeons are commonly consulted to provide anterior thoracic exposure for infection and malignant neoplasms involving the thoracolumbar spine. These cases can present significant technical and management challenges secondary to the underlying pathology, associated anatomic inflammation, and impaired functional status. In this study, we review the perioperative outcomes in patients undergoing anterior spinal exposure for infection and neoplasm. METHODS: 130 consecutive patients (61 women, 69 men) undergoing corpectomy, debridement, or debulking for osteomyelitis (n=50) or neoplasms (n=80) with decompression/stabilization at a single institution were analyzed. Primary endpoints included morbidity, mortality, and perioperative neurologic outcomes. RESULTS: The mean age was 61.1 years. A cervical/sternotomy (n=8) approach was used for levels C7 to T2, thoracotomy (n=79) for levels T3 to T10, and thoracoabdominal (n=43) for T11 to L2 involvement. Primary spinal neoplasms (n=22, 16.9 %) and metastases (n=58, 44.6%) were treated with corpectomy and prosthetic stabilization and were associated with increased operative time (310 vs 243 minutes, p=0.02) and blood loss (825 vs 500 mL, p=0.002). Osteomyelitis was associated with longer hospital stays (12 vs 7 days, p<0.001). The 30-day and 90-day mortality was 9.2% and 20.8%, respectively. The major complication rate was 27.7%. The median length of stay was 9 days. Surgical intervention resulted in significant improvement in pain, numbness, weakness, and bowel and bladder dysfunction. CONCLUSIONS: Anterior spinal exposure represents an important modality in facilitating the treatment of patients with osteomyelitis, pathologic fractures, and spinal cord compression syndromes. These procedures are associated with a significant risk of morbidity and mortality, but they are effective in achieving spinal stabilization and alleviating neurologic symptoms.


Assuntos
Osteomielite/mortalidade , Osteomielite/cirurgia , Neoplasias da Coluna Vertebral/mortalidade , Neoplasias da Coluna Vertebral/cirurgia , Toracotomia/métodos , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Desbridamento , Descompressão Cirúrgica/métodos , Feminino , Seguimentos , Humanos , Estimativa de Kaplan-Meier , Vértebras Lombares/patologia , Vértebras Lombares/cirurgia , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica/patologia , Estadiamento de Neoplasias , Osteomielite/diagnóstico , Posicionamento do Paciente/métodos , Assistência Perioperatória/métodos , Complicações Pós-Operatórias/fisiopatologia , Complicações Pós-Operatórias/terapia , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Medição de Risco , Índice de Gravidade de Doença , Fusão Vertebral/métodos , Neoplasias da Coluna Vertebral/patologia , Análise de Sobrevida , Vértebras Torácicas/patologia , Vértebras Torácicas/cirurgia , Resultado do Tratamento
19.
Bioinformatics ; 29(10): 1343-4, 2013 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-23446294

RESUMO

SUMMARY: Protein identification by mass spectrometry is commonly accomplished using a peptide sequence matching search algorithm, whose sensitivity varies inversely with the size of the sequence database and the number of post-translational modifications considered. We present the Spectrum Identification Machine, a peptide sequence matching tool that capitalizes on the high-intensity b1-fragment ion of tandem mass spectra of peptides coupled in solution with phenylisotiocyanate to confidently sequence the first amino acid and ultimately reduce the search space. We demonstrate that in complex search spaces, a gain of some 120% in sensitivity can be achieved. AVAILABILITY: All data generated and the software are freely available for academic use at http://proteomics.fiocruz.br/software/sim. CONTACT: paulo@pcarvalho.com SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Algoritmos , Proteínas de Escherichia coli/análise , Escherichia coli/química , Peptídeos/análise , Proteômica/métodos , Sequência de Aminoácidos , Proteínas de Escherichia coli/química , Espectrometria de Massas , Peptídeos/química , Processamento de Proteína Pós-Traducional , Software
20.
Proteomics ; 11(20): 4105-8, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21834134

RESUMO

The decoy-database approach is currently the gold standard for assessing the confidence of identifications in shotgun proteomic experiments. Here, we demonstrate that what might appear to be a good result under the decoy-database approach for a given false-discovery rate could be, in fact, the product of overfitting. This problem has been overlooked until now and could lead to obtaining boosted identification numbers whose reliability does not correspond to the expected false-discovery rate. To overcome this, we are introducing a modified version of the method, termed a semi-labeled decoy approach, which enables the statistical determination of an overfitted result.


Assuntos
Biologia Computacional , Proteômica/normas , Descoberta de Drogas/normas
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