Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
IEEE Trans Cybern ; 47(6): 1496-1509, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28113688

RESUMEN

This paper proposes a facial expression recognition system using evolutionary particle swarm optimization (PSO)-based feature optimization. The system first employs modified local binary patterns, which conduct horizontal and vertical neighborhood pixel comparison, to generate a discriminative initial facial representation. Then, a PSO variant embedded with the concept of a micro genetic algorithm (mGA), called mGA-embedded PSO, is proposed to perform feature optimization. It incorporates a nonreplaceable memory, a small-population secondary swarm, a new velocity updating strategy, a subdimension-based in-depth local facial feature search, and a cooperation of local exploitation and global exploration search mechanism to mitigate the premature convergence problem of conventional PSO. Multiple classifiers are used for recognizing seven facial expressions. Based on a comprehensive study using within- and cross-domain images from the extended Cohn Kanade and MMI benchmark databases, respectively, the empirical results indicate that our proposed system outperforms other state-of-the-art PSO variants, conventional PSO, classical GA, and other related facial expression recognition models reported in the literature by a significant margin.


Asunto(s)
Algoritmos , Emociones/clasificación , Cara/fisiología , Procesamiento de Imagen Asistido por Computador/métodos , Aprendizaje Automático , Reconocimiento de Normas Patrones Automatizadas/métodos , Bases de Datos Factuales , Cara/anatomía & histología , Humanos , Modelos Genéticos
2.
J Virol ; 91(1)2017 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-27795443

RESUMEN

The increase in AP-1 activity is a hallmark of cell transformation by tyrosine kinases. Previously, we reported that blocking AP-1 using the c-Jun dominant negative mutant TAM67 induced senescence, adipogenesis, or apoptosis in v-Src-transformed chicken embryo fibroblasts (CEFs) whereas inhibition of JunD by short hairpin RNA (shRNA) specifically induced apoptosis. To investigate the role of AP-1 in Src-mediated transformation, we undertook a gene profiling study to characterize the transcriptomes of v-Src-transformed CEFs expressing either TAM67 or the JunD shRNA. Our study revealed a cluster of 18 probe sets upregulated exclusively in response to AP-1/JunD impairment and v-Src transformation. Four of these probe sets correspond to genes involved in the interferon pathway. One gene in particular, death-associated protein kinase 1 (DAPK1), is a C/EBPß-regulated mediator of apoptosis in gamma interferon (IFN-γ)-induced cell death. Here, we show that inhibition of DAPK1 abrogates cell death in v-Src-transformed cells expressing the JunD shRNA. Chromatin immunoprecipitation data indicated that C/EBPß was recruited to the DAPK1 promoter while the expression of a dominant negative mutant of C/EBPß abrogated the induction of DAPK1 in response to the inhibition of AP-1. In contrast, as determined by chromatin immunoprecipitation (ChIP) assays, JunD was not detected on the DAPK1 promoter under any conditions, suggesting that JunD promotes survival by indirectly antagonizing the expression of DAPK1 in v-Src transformed cells. IMPORTANCE: Transformation by the v-Src oncoprotein causes extensive changes in gene expression in primary cells such as chicken embryo fibroblasts. These changes, determining the properties of transformed cells, are controlled in part at the transcriptional level. Much attention has been devoted to transcription factors such as AP-1 and NF-κB and the control of genes associated with a more aggressive phenotype. In this report, we describe a novel mechanism of action determined by the JunD component of AP-1, a factor enhancing cell survival in v-Src-transformed cells. We show that the loss of JunD results in the aberrant activation of a genetic program leading to cell death. This program requires the activation of the tumor suppressor death-associated protein kinase 1 (DAPK1). Since DAPK1 is phosphorylated and inhibited by v-Src, these results highlight the importance of this kinase and the multiple mechanisms controlled by v-Src to antagonize the tumor suppressor function of DAPK1.


Asunto(s)
Proteínas Quinasas Asociadas a Muerte Celular/genética , Fibroblastos/metabolismo , Proteína Oncogénica pp60(v-src)/genética , Proteínas Proto-Oncogénicas c-jun/genética , Factor de Transcripción AP-1/genética , Animales , Apoptosis/genética , Secuencia de Bases , Proteína beta Potenciadora de Unión a CCAAT/genética , Proteína beta Potenciadora de Unión a CCAAT/metabolismo , Supervivencia Celular , Células Cultivadas , Embrión de Pollo , Pollos , Inmunoprecipitación de Cromatina , Proteínas Quinasas Asociadas a Muerte Celular/metabolismo , Fibroblastos/citología , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Proteína Oncogénica pp60(v-src)/metabolismo , Plásmidos/química , Plásmidos/metabolismo , Unión Proteica , Proteínas Proto-Oncogénicas c-jun/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-jun/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Transducción de Señal , Factor de Transcripción AP-1/antagonistas & inhibidores , Factor de Transcripción AP-1/metabolismo , Transfección
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...