98 research outputs found

    Structural filtering of greylevel images from principal curvatures analysis

    Get PDF
    A new digital images smoothing method, named structural filtering, is proposed which uses a 3D representation of greylevel images (z =f(x, y)) and their description with principal curvature features . The organization of the horizontal projections of the principal curvature directions is analysed in order to determine a direction which well indicates the orientation of the local structure of the image . If such a direction is found, filtering is performed by averaging with a directional convolution mask according to that direction, if not, a classical 3 x 3 mean filter is used . This filter permits on one hand to cut off the noise while preserving step edges and ridges, on the other hand, it allows the schematization of the principal structures of the image . This last capability has never being obtained before with classical filters . Experimental results are shown through real images of textures made of complex structures and compared with those obtained with a 3 x 3 median filter . These results are then validated by primitive extraction using classical skeletonization or edge detection algorithms . At last, the behavior of the filter in function of the iteration number is analysed in order to show up its good convergence property .Une nouvelle mĂ©thode de filtrage d'images digitalisĂ©es, appelĂ©e filtrage structurel, est proposĂ©e . Elle utilise une repĂ©sentation tridimensionnelle des images Ă  niveaux de gris (x, y, z=f(x, y)) et leur description Ă  partir des courbures principales calculĂ©es en chaque point de la surface . L'organisation des projections horizontales des courbures principales est analysĂ©e en vue de dĂ©terminer une direction rendant compte de l'orientation locale de la structure au point considĂ©rĂ© . Si une direction de filtrage peut ĂȘtre dĂ©terminĂ©e, elle sert de support Ă  un masque moyenneur directionnel de convolution, sinon un masque moyenneur classique bidimensionnel de taille 3 x 3 est appliquĂ© . Ce filtre permet ainsi non seulement d'Ă©liminer le bruit en prĂ©servant les lignes de transition et de crĂȘte de l'image, mais aussi, il autorise la schĂ©matisation des structures prĂ©sentes dans l'image originale, cette derniĂšre propriĂ©tĂ© n'ayant jamais Ă©tĂ© jusqu'alors obtenue avec des mĂ©thodes de filtrage classiques . Des rĂ©sultats expĂ©rimentaux sont montrĂ©s Ă  partir d'images rĂ©elles de texture composĂ©es de structures complexes en les comparant avec ceux obtenus Ă  l'aide d'un filtre mĂ©dian 3 x 3 . Ces rĂ©sultats sont ensuite validĂ©s en effectuant une extraction de primitives telles que les lignes de squelette ou de contour . Enfin, une analyse du comportement du filtre en fonction du nombre d'itĂ©rations est faite qui met en valeur une propriĂ©tĂ© de bonne convergence

    The Multifunctional Sorting Protein PACS-2 Controls Mitophagosome Formation in Human Vascular Smooth Muscle Cells through Mitochondria-ER Contact Sites.

    Get PDF
    Mitochondria-associated ER membranes (MAMs) are crucial for lipid transport and synthesis, calcium exchange, and mitochondrial functions, and they also act as signaling platforms. These contact sites also play a critical role in the decision between autophagy and apoptosis with far reaching implications for cell fate. Vascular smooth muscle cell (VSMC) apoptosis accelerates atherogenesis and the progression of advanced lesions, leading to atherosclerotic plaque vulnerability and medial degeneration. Though the successful autophagy of damaged mitochondria promotes VSMC survival against pro-apoptotic atherogenic stressors, it is unknown whether MAMs are involved in VSMC mitophagy processes. Here, we investigated the role of the multifunctional MAM protein phosphofurin acidic cluster sorting protein 2 (PACS-2) in regulating VSMC survival following a challenge by atherogenic lipids. Using high-resolution confocal microscopy and proximity ligation assays, we found an increase in MAM contacts as in PACS-2-associated MAMs upon stimulation with atherogenic lipids. Correspondingly, the disruption of MAM contacts by PACS-2 knockdown impaired mitophagosome formation and mitophagy, thus potentiating VSMC apoptosis. In conclusion, our data shed new light on the significance of the MAM modulatory protein PACS-2 in vascular cell physiopathology and suggest MAMs may be a new target to modulate VSMC fate and favor atherosclerotic plaque stability

    Exploring Consumer Biased Evaluations : Halos Effects of Local Food and of Related Attributes

    Get PDF
    The paper explores the (mis)perceptions related to local food to identify potential halo effects. It also investigates whether product beliefs relate to the food category itself or to its perceived attributes. 133 students answered a questionnaire regarding four cheeses labelled as local, conventional, organic, or PDO. Results show that local claims lead to perceiving the cheese as healthier, but less hygienic. Results suggest also other two potential halos: (i) the \u201ctradition halo\u201d that links perceived traditional character to healthiness and taste; and (ii) the \u201cenvironmental and animal care halo\u201d that links respect for environment and animal welfare to food safety

    The Neurogenesis Actuator and NR2B/NMDA Receptor Antagonist Ro25-6981 Consistently Improves Spatial Memory Retraining Via Brain Region-Specific Gene Expression

    Get PDF
    NR2B-containing NMDA (NR2B/NMDA) receptors are important in controlling neurogenesis and are involved in generating spatial memory. Ro25-6981 is a selective antagonist at these receptors and actuates neurogenesis and spatial memory. Inter-structural neuroanatomical profiles of gene expression regulating adult neurogenesis and neuroapoptosis require examination in the context of memory retrieval and reversal learning. The aim was to investigate spatial memory retrieval and reversal learning in relation to gene expression-linked neurogenetic processes following blockade of NR2B/NMDA receptors by Ro25-6981. Rats were trained in Morris water maze (MWM) platform location for 5 days. Ro25-6981 was administered (protocol days 6–7) followed by retraining (days 15–18 or 29–32). Platform location was tested (on days 19 or 33) then post-mortem brain tissue sampling (on days 20 or 34). The expression of three genes known to regulate cell proliferation (S100a6), differentiation (Ascl1), and apoptosis (Casp-3) were concomitantly evaluated in the hippocampus, prefrontal cortex, and cerebellum in relation to the MWM performance protocol. Following initial training, Ro25-6981 enhanced visuospatial memory retrieval performance during further retraining (protocol days 29–32) but did not influence visuospatial reversal learning (day 33). Hippocampal Ascl1 and Casp-3 expressions were correspondingly increased and decreased while cerebellar S100a6 and Casp-3 activities were decreased and increased respectively 27 days after Ro25-6981 treatment. Chronological analysis indicated a possible involvement of new mature neurons in the reconfiguration of memory processes. This was attended by behavioral/gene correlations which revealed direct links between spatial memory retrieval enhancement and modified gene activity induced by NR2B/NMDA receptor blockade and upregulation

    AAV5-miHTT gene therapy demonstrates suppression of mutant huntingtin aggregation and neuronal dysfunction in a rat model of Huntington's disease.

    Get PDF
    Huntington's disease (HD) is a fatal progressive neurodegenerative disorder caused by a mutation in the huntingtin (HTT) gene. To date, there is no treatment to halt or reverse the course of HD. Lowering of either total or only the mutant HTT expression is expected to have therapeutic benefit. This can be achieved by engineered micro (mi)RNAs targeting HTT transcripts and delivered by an adeno-associated viral (AAV) vector. We have previously showed a miHTT construct to induce total HTT knock-down in Hu128/21 HD mice, while miSNP50T and miSNP67T constructs induced allele-selective HTT knock-down in vitro. In the current preclinical study, the mechanistic efficacy and gene specificity of these selected constructs delivered by an AAV serotype 5 (AAV5) vector was addressed using an acute HD rat model. Our data demonstrated suppression of mutant HTT messenger RNA, which almost completely prevented mutant HTT aggregate formation, and ultimately resulted in suppression of DARPP-32-associated neuronal dysfunction. The AAV5-miHTT construct was found to be the most efficient, although AAV5-miSNP50T demonstrated the anticipated mutant HTT allele selectivity and no passenger strand expression. Ultimately, AAV5-delivered-miRNA-mediated HTT lowering did not cause activation of microglia or astrocytes suggesting no immune response to the AAV5 vector or therapeutic precursor sequences. These preclinical results suggest that using gene therapy to knock-down HTT may provide important therapeutic benefit for HD patients and raised no safety concerns, which supports our ongoing efforts for the development of an RNA interference-based gene therapy product for HD

    Applying social influence insights to encourage climate resilient domestic water behaviour: Bridging the theory-practice gap

    Get PDF
    Water scarcity is one of the most pressing issues of our time and it is projected to increase as global demand surges and climate change limits fresh water availability. If we are to reduce water demand, it is essential that we draw on every tool in the box, including one that is underestimated and underutilised: social influence. Research from the psychological sciences demonstrates that behaviour is strongly influenced by the behaviour of others, and that social influence can be harnessed to develop cost-effective strategies to encourage climate resilient behaviour. Far less attention has been paid to investigating water-related interventions in comparison to interventions surrounding energy. In this paper we consider the application of three social influence strategies to encourage water conservation: social norms; social identity; and socially-comparative feedback. We not only review their empirical evidence base, but also offer an example of their application in the residential sector with the aim of highlighting how theoretical insights can be translated into practice. We argue that collaborations between researchers and industry are essential if we are to maximise the potential of behaviour change interventions to encourage climate resilient water behaviour

    Brain Potentials Highlight Stronger Implicit Food Memory for Taste than Health and Context Associations

    Get PDF
    Increasingly consumption of healthy foods is advised to improve population health. Reasons people give for choosing one food over another suggest that non-sensory features like health aspects are appreciated as of lower importance than taste. However, many food choices are made in the absence of the actual perception of a food's sensory properties, and therefore highly rely on previous experiences of similar consumptions stored in memory. In this study we assessed the differential strength of food associations implicitly stored in memory, using an associative priming paradigm. Participants (N = 30) were exposed to a forced-choice picture-categorization task, in which the food or non-food target images were primed with either non-sensory or sensory related words. We observed a smaller N400 amplitude at the parietal electrodes when categorizing food as compared to non-food images. While this effect was enhanced by the presentation of a food-related word prime during food trials, the primes had no effect in the non-food trials. More specifically, we found that sensory associations are stronger implicitly represented in memory as compared to non-sensory associations. Thus, this study highlights the neuronal mechanisms underlying previous observations that sensory associations are important features of food memory, and therefore a primary motive in food choice.</p

    Evaluations of People Depicted With Facial Disfigurement Compared to Those With Mobility Impairment

    Get PDF
    There are few extant studies of stereotyping of people with facial disfigurement. In the present study, two experiments (both within-participants) showed positive evaluations of people depicted as wheelchair users and, from the same participants, negative evaluations of people with facial disfigurements, compared to controls. The results of Experiment 2 suggested that implicit affective attitudes were more negative toward people with facial disfigurement than wheelchair users and were correlated with evaluation negativity. Social norms were perceived to permit more discrimination against people with facial disfigurement than against wheelchair users. These factors could help to explain the evaluative differences between the two disadvantaged groups

    Tracking Subtle Stereotypes of Children with Trisomy 21: From Facial-Feature-Based to Implicit Stereotyping

    Get PDF
    Background: Stigmatization is one of the greatest obstacles to the successful integration of people with Trisomy 21 (T21 or Down syndrome), the most frequent genetic disorder associated with intellectual disability. Research on attitudes and stereotypes toward these people still focuses on explicit measures subjected to social-desirability biases, and neglects how variability in facial stigmata influences attitudes and stereotyping. Methodology/Principal Findings: The participants were 165 adults including 55 young adult students, 55 non-student adults, and 55 professional caregivers working with intellectually disabled persons. They were faced with implicit association tests (IAT), a well-known technique whereby response latency is used to capture the relative strength with which some groups of people—here photographed faces of typically developing children and children with T21—are automatically (without conscious awareness) associated with positive versus negative attributes in memory. Each participant also rated the same photographed faces (consciously accessible evaluations). We provide the first evidence that the positive bias typically found in explicit judgments of children with T21 is smaller for those whose facial features are highly characteristic of this disorder, compared to their counterparts with less distinctive features and to typically developing children. We also show that this bias can coexist with negative evaluations at the implicit level (with large effect sizes), even among professional caregivers

    Effects of eight neuropsychiatric copy number variants on human brain structure

    Get PDF
    • 

    corecore