Ocaml-templates, méta-programmation à partir des types

Le système de type du langage Objective Caml interdit le paramétrage du type d'une fonction quelconque par un type explicite ou par la valeur d'un argument. Ainsi, les fonctions polymorphes définies par l'utilisateur ne peuvent observer précisément leurs arguments sans sortir du cadre typé. Par exemple, pour typer la fonction Printf.printf, il a fallu intégrer un cas spécifique au système d'inférence du compilateur. Cela empˆeche typiquement l'écriture d'une fonction print générique ou une fonction de sérialisation bien typée (le module Marshal qui s'occupe de la sérialisation ne permet pas de vérifier les structures lues). Un autre besoin en Objective Caml est celui d'itérateurs sur un type quelconque. Quelques modules fournissent des itérateurs polymorphes comme List.map ou Hashtbl.fold mais une extension est nécessaire pour générer une fonction de copie qui duplique une structure arbitraire ou des fonctions de parcourt compliquées. Nous proposons une extension de Objective Caml permettant de générer du code arbitraire à la compilation à partir d'informations de type comme la déclaration de type ou l'instance d'un type. Cette extension, appelée Ocaml-templates, est écrite à l'aide du préprocesseur Camlp4. Un prototype est téléchargeable sur http://www.pps.jussieu.fr/~maurel/programmation/

The qnu and qnuK calculi, name capture and control (Extended Abstract)

We introduce a pithy calculus obtained by splitting the lambda binder of the lambda-calculus into two constructions : a pure binder nu, à la pi-calculus, and a combinator for beta-reduction. This splitting allows a powerful -- yet controlled -- rebinding mechanism. Using the same splitting with continuations allows the expression of both local and global exceptions in the same clean calculus. We also exhibit a typing system with variable initialisation and exception handling analysis

An Analysis of the Performances of the CasEN Named Entities Recognition System in the Ester2 Evaluation Campaign

8 pagesIn this paper, we present a detailed and critical analysis of the behaviour of the CasEN named entity recognition system during the French Ester2 evaluation campaign. In this project, CasEN has been confronted with the task of detecting and categorizing named entities in manual and automatic transcriptions of radio broadcastings. At first, we give a general presentation of the Ester2 campaign. Then, we describe our system, based on transducers. Next, we depict how systems were evaluated during this campaign and we report the main official results. Afterwards, we investigate in details the influence of some annotation biases which have significantly affected the estimation of the performances of systems. At last, we conduct an in-depth analysis of the effective errors of the CasEN system, providing us with some useful indications about phenomena that gave rise to errors (e.g. metonymy, encapsulation, detection of right boundaries) and are as many challenges for named entity recognition systems

Hydrodynamique de l'accumulation des dépôts de paraffine dans une géométrie Couette cylindrique.

The models used to predict a wax deposit overestimate it and they need some parameters fitting to match computational data to experimental ones In this study, a new approach is proposed. A waxy crude oil is considered as a viscoplastic fluid. An extension of classical Bingham model in which both viscosity and yield stress depend on temperature and wax crystal is used. Numerical simulations of the flow in a Couette geometry were carried out to show that this approach is relevant. The numerical results highlight the influence of wax crystals content on the flow pattern, especially in terms of yielded /unyielded regions. A static layer region appears near the colder wall, representing the deposit

Influence du cisaillement macroscopique sur la propagation d'une fissure située à l'interface d'un revêtement céramique et d'un substrat métallique

International audienceLes dépôts des revêtements projetés sont le plus souvent réalisés à chaud (jet plasma, faisceau d'électron...) ou avec des échauffements locaux importants au cours du dépôt (cold spray). Lors de l'utilisation des pièces, la température étant généralement différente de la température de dépôt, l'écart de coefficients de dilatation thermique entre les couches du système conduit à un état de ..

Syndecan-1 antigen, a promising new target for triple-negative breast cancer immuno-PET and radioimmunotherapy. A preclinical study on MDA-MB-468 xenograft tumors

International audienceBackgroundOverexpression of syndecan-1 (CD138) in breast carcinoma correlates with a poor prognosis and an aggressive phenotype. The objective of this study was to evaluate the potential of targeting CD138 by immuno-PET imaging and radioimmunotherapy (RIT) using the antihuman syndecan-1 B-B4 mAb radiolabeled with either 124I or 131I in nude mice engrafted with the triple-negative MDA-MB-468 breast cancer cell line.MethodThe immunoreactivity of 125I-B-B4 (80%) was determined, and the affinity of 125I-B-B4 and the expression of CD138 on MDA-MB-468 was measured in vitro by Scatchard analysis. CD138 expression on established tumors was confirmed by immunohistochemistry. A biodistribution study was performed in mice with subcutaneous MDA-MB-468 and 125I-B-B4 at 4, 24, 48, 72, and 96 h after injection and compared with an isotype-matched control. Tumor uptake of B-B4 was evaluated in vivo by immuno-PET imaging using the 124I-B-B4 mAb. The maximum tolerated dose (MTD) was determined from mice treated with 131I-B-B4 and the RIT efficacy evaluated.Results 125I-B-B4 affinity was in the nanomolar range (Kd = 4.39 ± 1.10 nM). CD138 expression on MDA-MB-468 cells was quite low (Bmax = 1.19 × 104 ± 9.27 × 102 epitopes/cell) but all expressed CD138 in vivo as determined by immunohistochemistry. The tumor uptake of 125I-B-B4 peaked at 14% injected dose (ID) per gram at 24 h and was higher than that of the isotype-matched control mAb (5% ID per gram at 24 h). Immuno-PET performed with 124I-B-B4 on tumor-bearing mice confirmed the specificity of B-B4 uptake and its retention within the tumor. The MTD was reached at 22.2 MBq. All mice treated with RIT (n = 8) as a single treatment at the MTD experienced a partial (n = 3) or complete (n = 5) response, with three of them remaining tumor-free 95 days after treatment.ConclusionThese results demonstrate that RIT with 131I-B-B4 could be considered for the treatment of metastatic triple-negative breast cancer that cannot benefit from hormone therapy or anti-Her2/neu immunotherapy. Immuno-PET for visualizing CD138-expressing tumors with 124I-B-B4 reinforces the interest of this mAb for diagnosis and quantitative imaging

Differential activity of methylene blue against erythrocytic and hepatic stages of Plasmodium

Background: In the context of malaria elimination/eradication, drugs that are effective against the different developmental stages of the parasite are highly desirable. The oldest synthetic anti-malarial drug, the thiazine dye methylene blue (MB), is known for its activity against Plasmodium blood stages, including gametocytes. The aim of the present study was to investigate a possible effect of MB against malaria parasite liver stages. Methods: MB activity was investigated using both in vitro and in vivo models. In vitro assays consisted of testing MB activity on Plasmodium falciparum, Plasmodium cynomolgi and Plasmodium yoelii parasites in human, simian or murine primary hepatocytes, respectively. MB in vivo activity was evaluated using intravital imaging in BALB/c mice infected with a transgenic bioluminescent P. yoelii parasite line. The transmission-blocking activity of MB was also addressed using mosquitoes fed on MB-treated mice. Results: MB shows no activity on Plasmodium liver stages, including hypnozoites, in vitro in primary hepatocytes. In BALB/c mice, MB has moderate effect on P. yoelii hepatic development but is highly effective against blood stage growth. MB is active against gametocytes and abrogates parasite transmission from mice to mosquitoes. Conclusion: While confirming activity of MB against both sexual and asexual blood stages, the results indicate that MB has only little activity on the development of the hepatic stages of malaria parasites