Post-Reconstruction Deconvolution of PET Images by Total Generalized Variation Regularization

Improving the quality of positron emission tomography (PET) images, affected by low resolution and high level of noise, is a challenging task in nuclear medicine and radiotherapy. This work proposes a restoration method, achieved after tomographic reconstruction of the images and targeting clinical situations where raw data are often not accessible. Based on inverse problem methods, our contribution introduces the recently developed total generalized variation (TGV) norm to regularize PET image deconvolution. Moreover, we stabilize this procedure with additional image constraints such as positivity and photometry invariance. A criterion for updating and adjusting automatically the regularization parameter in case of Poisson noise is also presented. Experiments are conducted on both synthetic data and real patient images.Comment: First published in the Proceedings of the 23rd European Signal Processing Conference (EUSIPCO-2015) in 2015, published by EURASI

Saint-Péray – Chemin de Biousse

L’aménagement d’une maison d’habitation a suscité la prescription d’un diagnostic archéologique au lieu-dit du Chemin de Biousse, au vu du contexte archéologique proche. À 300 m plus au nord-ouest, du mobilier céramique a fait l’objet d’un ramassage de surface dans les années 1980. Ce mobilier, associé à deux monnaies de Constance II et de Julien, atteste de la production de deux types de céramique de la fin du ive s. : céramique commune et fine à engobe argileux non grésé (DSP) (Dupraz, Frai..

Saint-Romain-en-Gal – 496 route de Rive-de-Gier

Le diagnostic archéologique a été prescrit par les services de l’État sur les parcelles AK 84, 173 et 176, implantées sur le versant ouest de la vallée du Rhône, à l’ouest du bourg actuel de Saint-Romain-en-Gal. Localisé au 496 route de Rive-de-Gier, il a été mis en œuvre préalablement à la construction de plusieurs immeubles d’habitation. Cette opération est menée à quelques centaines de mètres d’un contexte archéologique très dense, avec notamment le parc archéologique et le Musée de Sa..

Le renouveau du conflit ville-campagne par les représentations sociales du développement durable. L'exemple de l'aire urbaine d'Orléans

International audienceSocial representations of sustainable development may be grasped as a keystone structured by two models: the first one refers to the institutional and scientific paradigm of " sustainable town " with density, mixity and centrality; the second one is more popular and built from anti-urban principles, and calls back to rural area qualities with " nature " ideal and lower density. In the end, this schematic distinction repeats the opposition between " town " and " countryside " in sustainable development and urban planning practices. Based on the example of the urban area of Orléans, fragmented along a centre-periphery scheme, this communication focuses on the notions of " lived area " for inhabitants, analysed with a photographic survey, and of " conceived area " for elected officials, treated with semi-structured interviews and the use of institutional documents.Les représentations sociales du développement durable peuvent être appréhendées comme une ligne de force structurée à partir de deux modèles : le premier, en tant que paradigme institutionnel et scientifique de la « ville durable », celui de la densité, de la mixité et de la centralité ; le second, plus « populaire » et construit à partir de valeurs anti-urbaines, ramène aux qualités des espaces ruraux, définies par leur idéal de « nature » et de faibles densités. Au final, cette distinction schématique entre deux modèles territoriaux renouvelle l'opposition entre les catégories de la « ville » et de la « campagne » dans les pratiques du développe-ment durable et d'aménagement du territoire. À partir de l'exemple de l'aire urbaine d'Orléans, territoire fragmenté selon un schéma centre-périphérie, la communication se focalise sur les notions d'« espace vécu » des habitants, analysé au travers d'un questionnaire photographique, et d'« espace conçu » des élus, traité grâce à des entretiens semi-directifs et l'exploitation de documents institutionnels

Mesenchymal stem cell-based therapies in regenerative medicine: applications in rheumatology

Growing knowledge on the biology of mesenchymal stem cells (MSCs) has provided new insights into their potential clinical applications, particularly for rheumatologic disorders. Historically, their potential to differentiate into cells of the bone and cartilage lineages has led to a variety of experimental strategies to investigate whether MSCs can be used for tissue engineering approaches. Beyond this potential, MSCs also display immunosuppressive properties, which have prompted research on their capacity to suppress local inflammation and tissue damage in a variety of inflammatory autoimmune diseases and, in particular, in rheumatoid arthritis. Currently, an emerging field of research comes from the possibility that these cells, through their trophic/regenerative potential, may also influence the course of chronic degenerative disorders and prevent cartilage degradation in osteoarthritis. This review focuses on these advances, specifically on the biological properties of MSCs, including their immunoregulatory characteristics, differentiation capacity and trophic potential, as well as the relevance of MSC-based therapies for rheumatic diseases

Effects of the relative timing of opposite-polarity pulses on loudness for cochlear implant listeners.

The symmetric biphasic pulses used in contemporary cochlear implants (CIs) consist of both cathodic and anodic currents, which may stimulate different sites on spiral ganglion neurons and, potentially, interact with each other. The effect on the order of anodic and cathodic stimulation on loudness at short inter-pulse intervals (IPIs; 0-800 μs) is investigated. Pairs of opposite-polarity pseudomonophasic (PS) pulses were used and the amplitude of each pulse was manipulated independently. In experiment 1 the two PS pulses differed in their current level in order to elicit the same loudness when presented separately. Six users of the Advanced Bionics CI (Valencia, CA) loudness-ranked trains of the pulse pairs using a midpoint-comparison procedure. Stimuli with anodic-leading polarity were louder than those with cathodic-leading polarity for IPIs shorter than 400 μs. This effect was small-about 0.3 dB-but consistent across listeners. When the same procedure was repeated with both PS pulses having the same current level (experiment 2), anodic-leading stimuli were still louder than cathodic-leading stimuli at very short intervals. However, when using symmetric biphasic pulses (experiment 3) the effect disappeared at short intervals and reversed at long intervals. Possible peripheral sources of such polarity interactions are discussed