933 research outputs found
The Velocites of Hydrolysis of the Three Monomethoxy-Diphenyl Ketimines
The 2- and the 3-methoxy-diphenyl ketimines have been prepared employing the general method of Moureu and Mignonac. The 4-methoxy-diphenyl ketimine had been prepared previously
Leaf segmentation and tracking using probabilistic parametric active contours
Active contours or snakes are widely used for segmentation and tracking. These techniques require the minimization of an energy function, which is generally a linear combination of a data fit term and a regularization term. This energy function can be adjusted to exploit the intrinsic object and image features. This can be done by changing the weighting parameters of the data fit and regularization term. There is, however, no rule to set these parameters optimally for a given application. This results in trial and error parameter estimation. In this paper, we propose a new active contour framework defined using probability theory. With this new technique there is no need for ad hoc parameter setting, since it uses probability distributions, which can be learned from a given training dataset
Multiscale Image Segmentation Using Active Contours
We propose a new approach for image segmentation at different scales of observation, based on a multiscale image decomposition and on the active contour segmentation model. The proposed method consists of two steps. Firstly, a representation of a given image at multiple scales is derived, by means of a smoothing method which minimizes the weighted total variation norm of the image. This method allows the longtime preservation of edges and contrast with increasing scale, facilitating the detection of underlying structures. Secondly, image structures are extracted at each scale, using a level set formulation of active contours, minimizing the Mumford-Shah functional. Promising results of the proposed segmentation approach on natural images are reported
The Total Filmmaker: thinking of screenwriting, directing and editing as one role
As screenwriting continues to establish itself as a discrete discipline in academia, either in alignment with creative writing departments or film and media practice departments, there is a danger that such developments may entrench a distancing of the craft from the cinematic form itself and that such a distancing may ultimately reinforce the screenplay's propensity for dramaturgy and the dramatic, rather than the sensory and experiential of the cinematic. Closely related creative stages in telling cinematic stories include directing and editing and this article seeks to argue, with reference to personal screen practice, that screenwriting, directing and editing are, in fact, three variations of the same thing. The article proposes the notion of the Total Filmmaker who embraces all three aspects of the cinematic storyteller. If the ultimate aim is to create a narrative that fully utilises the unique properties of the cinematic form in telling a story, rather than being dominated by the theatricality of dramatically driven classical narratives. How might one explore the relationship between screenwriting, directing and editing? Can an integrated approach to creating the cinematic blueprint change the way we think of pedagogy and screenwriting
Human recombinant anti-thyroperoxidase autoantibodies: in vitro cytotoxic activity on papillary thyroid cancer expressing TPO
International audienceBACKGROUND: Thyroid cancers are difficult to treat due to their limited responsiveness to chemo- and radiotherapy. There is thus a great interest in and a need for alternative therapeutic approaches. RESULTS: We studied the cytotoxic activity of anti-thyroperoxidase autoantibodies (anti-TPO aAbs, expressed in baculovirus/insect cell (B4) and CHO cells (B4') or purified from patients' sera) against a papillary thyroid cancer (NPA) cell line. Anti-TPO aAbs from patients' sera led to a partial destruction of NPA cell line by complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC) and exhibited an anti-proliferative activity. Comparison of the cytotoxic activity of anti-TPO aAbs shows that B4' induced an anti-proliferative effect and a better ADCC than B4, but a lower one than anti-TPO aAbs from patients' sera. Antibody-dependent cell-mediated cytotoxicity was increased when human peripheral blood mononuclear cells were used as effector cells, suggesting that FcgammaRs, CD64, CD32 and CD16 are involved. Indeed, anti-TPO aAbs from patients' sera, but not B4 and B4', exhibited CDC activity. CONCLUSIONS: These data indicate that anti-TPO aAbs display moderate ADCC and anti-proliferative activities on NPA cells; IgG glycosylation appears to be important for cytotoxic activity and ADCC efficiency depends on FcgammaR-bearing cells. Finally, recombinant human anti-TPO aAbs cannot yet be considered as an optimal tool for the development of a novel therapeutic approach for thyroid cancer
White Matter Mapping in DT-MRI Using Geometric Flows
We present a 3D geometric flow designed to evolve in Diffusion Tensor Magnetic Resonance Images(DT-MRI) along fiber tracts by measuring the diffusive similarity between voxels. Therefore we define a front propagation speed that is proportional to the similarity between the tensors lying on the surface and its neighbor in the propagation direction. The method is based on the assumption that successive voxels in a tract have similar diffusion properties. The front propagation is implemented using level set methods by Osher and Sethian [1] to simplify the handling of topology changes and provides an elegant tool for smoothing the segmented tracts. While many methods demand a regularized tensor field, our geometrical flow performs a regularization as it evolves along the fibers. This is done by a curvature dependent smoothing term adapted for thin tubular structures. The purpose of our approach is to get a quantitative measure of the diffusion in segmented fiber tracts. This kind of information can also be used for white matter registration and for surgical planning
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