A video object generation tool allowing friendly user interaction

In this paper we describe an interactive video object segmentation tool developed in the framework of the ACTS-AC098 MOMUSYS project. The Video Object Generator with User Environment (VOGUE) combines three different sets of automatic and semi-automatic-tool (spatial segmentation, object tracking and temporal segmentation) with general purpose tools for user interaction. The result is an integrated environment allowing the user-assisted segmentation of any sort of video sequences in a friendly and efficient manner.Peer ReviewedPostprint (published version

Partition-based image representation as basis for user-assisted segmentation

This paper discusses the usefulness of a partition-based image representation in the context of user-assisted segmentation, and compares it with the two other most common image representations in this framework: pixel-based and transition-based. Partition-based image representations allow user-interaction at the region level, which is a very natural and friendly manner to interact with images. The paper describes various region-based implementations of the most common types of user interaction; namely, initial object selection, object refinement, imposing object characteristics, selection of specific objects, selection of objects that are similar to a previously selected one. In all cases, partition-based image representations, and their associated region-based tools for user interaction, show up to be very suitable for interactive image segmentation.Peer Reviewe

Partition-based image representation as basis for user-assisted segmentation

This paper discusses the usefulness of a partition-based image representation in the context of user-assisted segmentation, and compares it with the two other most common image representations in this framework: pixel-based and transition-based. Partition-based image representations allow user-interaction at the region level, which is a very natural and friendly manner to interact with images. The paper describes various region-based implementations of the most common types of user interaction; namely, initial object selection, object refinement, imposing object characteristics, selection of specific objects, selection of objects that are similar to a previously selected one. In all cases, partition-based image representations, and their associated region-based tools for user interaction, show up to be very suitable for interactive image segmentation.Peer Reviewe

Convergent Functional Genomics of Oligodendrocyte Differentiation Identifies Multiple Autoinhibitory Signaling Circuits▿ †

Inadequate remyelination of brain white matter lesions has been associated with a failure of oligodendrocyte precursors to differentiate into mature, myelin-producing cells. In order to better understand which genes play a critical role in oligodendrocyte differentiation, we performed time-dependent, genome-wide gene expression studies of mouse Oli-neu cells as they differentiate into process-forming and myelin basic protein-producing cells, following treatment with three different agents. Our data indicate that different inducers activate distinct pathways that ultimately converge into the completely differentiated state, where regulated gene sets overlap maximally. In order to also gain insight into the functional role of genes that are regulated in this process, we silenced 88 of these genes using small interfering RNA and identified multiple repressors of spontaneous differentiation of Oli-neu, most of which were confirmed in rat primary oligodendrocyte precursors cells. Among these repressors were CNP, a well-known myelin constituent, and three phosphatases, each known to negatively control mitogen-activated protein kinase cascades. We show that a novel inhibitor for one of the identified genes, dual-specificity phosphatase DUSP10/MKP5, was also capable of inducing oligodendrocyte differentiation in primary oligodendrocyte precursors. Oligodendrocytic differentiation feedback loops may therefore yield pharmacological targets to treat disease related to dysfunctional myelin deposition

Functional Whole-genome Analysis Identifies Polo-like Kinase 2 and Poliovirus Receptor as Essential for Neuronal Differentiation Upstream of the Negative Regulator αB-crystallin

This study aimed at identifying transcriptional changes associated to neuronal differentiation induced by six distinct stimuli using whole-genome microarray hybridization analysis. Bioinformatics analyses revealed the clustering of these six stimuli into two categories, suggesting separate gene/pathway dependence. Treatment with specific inhibitors demonstrated the requirement of both Janus kinase and microtubule-associated protein kinase activation to trigger differentiation with nerve growth factor (NGF) and dibutyryl cAMP. Conversely, activation of protein kinase A, phosphatidylinositol-3-kinase α, and mammalian target of rapamycin, although required for dibutyryl cAMP-induced differentiation, exerted a negative feedback on NGF-induced differentiation. We identified Polo-like kinase 2 (Plk2) and poliovirus receptor (PVR) as indispensable for NGF-driven neuronal differentiation and αB-crystallin (Cryab) as an inhibitor of this process. Silencing of Plk2 or PVR blocked NGF-triggered differentiation and Cryab down-regulation, while silencing of Cryab enhanced NGF-induced differentiation. Our results position both Plk2 and PVR upstream of the negative regulator Cryab in the pathway(s) leading to neuronal differentiation triggered by NGF