144 research outputs found
UFPR-Periocular: A Periocular Dataset Collected by Mobile Devices in Unconstrained Scenarios
Recently, ocular biometrics in unconstrained environments using images
obtained at visible wavelength have gained the researchers' attention,
especially with images captured by mobile devices. Periocular recognition has
been demonstrated to be an alternative when the iris trait is not available due
to occlusions or low image resolution. However, the periocular trait does not
have the high uniqueness presented in the iris trait. Thus, the use of datasets
containing many subjects is essential to assess biometric systems' capacity to
extract discriminating information from the periocular region. Also, to address
the within-class variability caused by lighting and attributes in the
periocular region, it is of paramount importance to use datasets with images of
the same subject captured in distinct sessions. As the datasets available in
the literature do not present all these factors, in this work, we present a new
periocular dataset containing samples from 1,122 subjects, acquired in 3
sessions by 196 different mobile devices. The images were captured under
unconstrained environments with just a single instruction to the participants:
to place their eyes on a region of interest. We also performed an extensive
benchmark with several Convolutional Neural Network (CNN) architectures and
models that have been employed in state-of-the-art approaches based on
Multi-class Classification, Multitask Learning, Pairwise Filters Network, and
Siamese Network. The results achieved in the closed- and open-world protocol,
considering the identification and verification tasks, show that this area
still needs research and development
NADPH Oxidase and the Degeneration of Dopaminergic Neurons in Parkinsonian Mice
Several lines of investigation have implicated oxidative stress in Parkinsonâs disease (PD) pathogenesis, but the mechanisms involved are still unclear. In this study, we characterized the involvement of NADPH oxidase (Nox), a multisubunit enzyme that catalyzes the reduction of oxygen, in the 6-hydroxydopamine- (6-OHDA-) induced PD mice model and compared for the first time the effects of this neurotoxin in mice lacking gp91phox-/-, the catalytic subunit of Nox2, and pharmacological inhibition of Nox with apocynin. Six-OHDA induced increased protein expression of p47phox, a Nox subunit, in striatum. gp91phox-/- mice appear to be completely protected from dopaminergic cell loss, whereas the apocynin treatment conferred only a limited neuroprotection. Wt mice treated with apocynin and gp91phox-/- mice both exhibited ameliorated apomorphine-induced rotational behavior. The microglial activation observed within the striatum and the substantia nigra pars compacta (SNpc) of 6-OHDA-injected Wt mice was prevented by apocynin treatment and was not detected in gp91phox-/- mice. Apocynin was not able to attenuate astrocyte activation in SN. The results support a role for Nox2 in the 6-OHDA-induced degeneration of dopaminergic neurons and glial cell activation in the nigrostriatal pathway and reveal that no comparable 6-OHDA effects were observed between apocynin-treated and gp91phox-/- mice groups
New insights into purinergic receptor signaling in neuronal differentiation, neuroprotection, and brain disorders
Ionotropic P2X and metabotropic P2Y purinergic receptors are expressed in the central nervous system and participate in the synaptic process particularly associated with acetylcholine, GABA, and glutamate neurotransmission. As a result of activation, the P2 receptors promote the elevation of free intracellular calcium concentration as the main signaling pathway. Purinergic signaling is present in early stages of embryogenesis and is involved in processes of cell proliferation, migration, and differentiation. The use of new techniques such as knockout animals, in vitro models of neuronal differentiation, antisense oligonucleotides to induce downregulation of purinergic receptor gene expression, and the development of selective inhibitors for purinergic receptor subtypes contribute to the comprehension of the role of purinergic signaling during neurogenesis. In this review, we shall discuss the participation of purinergic receptors in developmental processes and in brain physiology, including neuron-glia interactions and pathophysiology
The importance of the ligation of the inferior thyroid artery in parathyroid function after subtotal thyroidectomy
We prospectively studied the effects of the ligation of the inferior thyroid artery (ITA) on postoperative hypoparathyroidism in 48 patients who underwent functional subtotal thyroidectomy. Patients were randomized into two groups: A, with bilateral ligation of the ITA and B, without ligation of the ITA. Parathyroid function was checked preoperatively and after surgery by clinical examination and measurement of total calcium, intact PTH, urinary calcium, and AMPc. RESULTS: A significant incidence of postoperative hypocalcemia occurred: 17% in group A and 13% in B on the 4th postoperative day. Six months later, the incidence was 5% in Group A and 0% in Group B. These differences were not statistically significant between the two groups, and neither were any of the other clinical and laboratory observations. CONCLUSION: The ligation of the ITA was not an important causal factor for the occurrence of postoperative hypocalcemia after subtotal thyroidectomy.Com o objetivo de observar os efeitos da ligadura da artĂ©ria tireoidiana inferior (ITA) no hipoparatireoidismo, 48 pacientes submetidos Ă tireoidectomia subtotal funcional foram estudados de forma prospectiva. Dois grupos foram randomizados, A: com a ligadura troncular bilateral da ITA e B: sem a ligadura troncular da ITA. A função paratireoidiana foi verificada no perĂodo prĂ©-operatĂłrio e apĂłs a cirurgia atravĂ©s de exame clĂnico e dosagens de cĂĄlcio total, PTH, cĂĄlcio urinĂĄrio e cAMP. Os resultados demostraram incidĂȘncia importante e significativa de hipocalcemia pĂłs-operatĂłria, de 17% no grupo A e 13% no grupo B no 4Âș PO. Seis meses apĂłs, a incidĂȘncia foi de 5% no grupo A e 0% no grupo B. Estas diferenças nĂŁo foram estatisticamente significativas entre os dois grupos, nem nenhum dos outros dados clĂnicos ou laboratoriais estudados. ConcluĂmos que a ligadura da ITA nĂŁo Ă© um fator causal importante de hipocalcemia pĂłs-operatĂłria apĂłs tireoidectomia subtotal
Inspeção Automåtica de Defeitos em Madeiras de Pinus usando Visão Computacional
This paper addresses the issue of detecting defects in Pine wood using features extracted from grayscale images. The feature set proposed here is based on the concept of texture and it is computed from the co-occurrence matrices. The features provide measures of properties such as smoothness, coarseness, and regularity. Comparative experiments using a color image based feature set extracted from percentile histograms are carried to demonstrate the efficiency of the proposed feature set. Two different learning paradigms, neural networks and support vector machines, and a feature selection algorithm based on multi-objective genetic algorithms were considered in our experiments. The experimental results show that after feature selection, the grayscale image based feature set achieves very competitive performance for the problem of wood defect detection relative to the color image based features.Este artigo apresenta um mĂ©todo completo para a detecção de defeitos em tĂĄbuas de madeira de Pinus atravĂ©s de tĂ©cnicas de VisĂŁo Computacional. As imagens dos lados da tĂĄbua de madeira sĂŁo adquiridas com cĂąmeras tipo line scan e processadas para extração de caracterĂsticas baseadas na informação cor e em propriedades de textura: suavidade, aspereza e regularidade. Um subconjunto destas caracterĂsticas, extraĂdo a partir de imagens em nĂveis de cinza e selecionado com base em algoritmos genĂ©ticos multi-objetivos Ă© proposto como alternativa para redução de custos no processo de aquisição de imagens. Dois paradigmas de aprendizagem de mĂĄquina diferentes foram utilizados: redes neurais e mĂĄquinas de vetor de suporte. Resultados experimentais demonstram que o conjunto de caracterĂsticas selecionado a partir de imagens em nĂveis de cinza atingiu desempenho competitivo para o problema de detecção de defeitos em madeira, quando comparado com conjunto de caracterĂsticas que depende de sensor de aquisição de maior custo (line scan colorida) para extração de caracterĂsticas baseadas na informação cor
Different protocols of physical exercise produce different effects on synaptic and structural proteins in motor areas of the rat brain
The plastic brain responses generated by the training with acrobatic exercise (AE) and with treadmill exercise (TE) may be different. We evaluated the protein expression of synapsin I (SYS), synaptophysin (SYP), microtubule-associated protein 2 (MAP2) and neurofilaments (NF) by immunohistochemistry and Western blotting in the motor cortex, striatum and cerebellum of rats subjected to TE and AE. Young adult male Wistar rats were divided into 3 groups: sedentary (Sed) (n=15), TE (n=20) and AE (n=20). The rats were trained 3 days/week for 4 weeks on a treadmill at 0.6 km/h, 40 min/day (TE), or moved through a circuit of obstacles 5 times/day (AE). The rats from the TE group exhibited a significant increase of SYS and SYP in the motor cortex, of NF68, SYS and SYP in the striatum, and of MAP2, NF and SYS in the cerebellum, whereas NF was decreased in the motor cortex and the molecular layer of the cerebellar cortex. On the other hand, the rats from the AE group showed a significant increase of MAP2 and SYP in the motor cortex, of all four proteins in the striatum, and of SYS in the cerebellum. In conclusion, AE induced changes in the expression of synaptic and structural proteins mainly in the motor cortex and striatum, which may underlie part of the learning of complex motor tasks. TE, on the other hand, promoted more robust changes of structural proteins in all three regions, especially in the cerebellum, which is involved in learned and automatic tasks. (C) 2012 Elsevier B.V. All rights reserved.FAPESPFAPESPCNPqCNP
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