The Arf tumor suppressor protein inhibits Miz1 to suppress cell adhesion and induce apoptosis

Arf assembles a complex containing Miz1, heterochromatin, and histone H3K3 to block expression of genes involved in cell adhesion and signal transduction. The resulting blockade of cell–cell and cell–matrix interactions facilitates elimination of cells carrying oncogenic mutations

Geochemical evaluation of the Lueshe niobium deposit (Zaire) by Rietveld quantitative X-ray diffraction

The Lueshe Nb deposit is used as an example to show that a modal analysis of fine-grained samples can readily be obtained by X-ray powder diffraction and the Rietveld method. This permits applications such as the visualisation of the weathering profile, the calculation of enrichment factors and estimation of the amount of nondiffracting material. This quantification method is based on the knowledge of the structural parameters of all the phases present in the sample and, in the case of geological material (especially secondary minerals), it sometimes requires structure refinement to optimize the results. (C) 1997 Elsevier Science Ltd

Raman spectroscopy of free-standing individual semiconducting single-wall carbon nanotubes

International audienceThe radial breathing modes and tangential modes have been systematically measured on a large number of individual semiconducting single-wall carbon nanotubes (thin bundles) suspended between plots (free-standing single-wall carbon nanotubes). The strong intensity of the Raman spectra ensures the precision of the experimentally determined line shapes and frequencies of these modes. The diameter dependence of the frequencies of the tangential modes was measured. This dependence is discussed in relation with recent calculations. The present data confirm/contradict some previous interpretations

Épandage des pesticides agricoles : état des connaissances sur les pertes directes et déterminants des améliorations techniques possibles

National audienceAvec une contamination importante de l'eau, des sols et de l'air par les produits phytosanitaires, les traitements phytosanitaires sont de plus en plus souvent mis à l'index. En effet des pratiques inadaptées peuvent générer des pollutions ponctuelles ou diffuses. Les pollutions ponctuelles (ou accidentelles) sont à priori les plus faciles à identifier et aussi à résoudre en mettant en oeuvre des pratiques, des techniques et des infrastructures adaptées. Les pollutions diffuses, du fait de la difficulté pour définir leur source et leurs contributions respectives au niveau de pollution globale sont plus difficiles à percevoir et au final à corriger. De plus elles sont dépendantes de chaque situation technique et géographique. En définitive, sur un territoire donné, les niveaux de contamination des sols, des eaux ou de l'air sont la résultante d'un ensemble de mécanismes complexes avec la contribution de nombreux acteurs directs ou indirects et très dépendants les uns des autres. La dynamique de ces contaminations est d'autre part très liée aux évènements météorologiques. Cette situation est d'autant plus complexe qu'un nombre très important de produits et leurs métabolites sont en cause, que ce soit en agriculture conventionnelle ou biologique. La réflexion qui suit porte à la fois sur l'état des connaissances sur les niveaux de pertes, leurs principales causes techniques, les solutions correctives possibles et les déterminants sociologiques et économiques qui devraient permettre de les réduir

Calcium and tocopherol suppress cured-meat promotion of colon carcinogenesis in rats. A volunteer study also suggests prevention in humans

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Cooked beef meat, and cured pork meat promotion of tumors in Apc(Min) mice. Plant extracts added to meat show no protection

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Decitrait® : un OAD pour la protection de la vigne

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Decitrait® : un OAD pour la protection de la vigne

International audienceThe dual performance, both economic and environmental, is a major challenge for the wine industry, which remains highly dependent on the use of pesticides. Fungicide control alone accounts for 80% of inputs in France. A DSS (DeciTrait®) gathering all the information necessary for the implementation of a low pesticides protection against the main fungal diseases (downy mildew - powdery mildew - black-rot - grey mould) was conceived in a collaborative approach within a CASDAR project. This DSS is easy to use and offers the user a protection strategy at the plot level based on the information and knowledge collected. The bioassays carried out within the CASDAR project clearly demonstrate the potential for reduction of phytosanitary inputs allowed by this DSS, for reducing both the number of treatments and the dose applied.La double performance, économique et environnementale, constitue un enjeu majeur pour la filière viticole qui demeure très dépendante de l’utilisation des pesticides. A elle seule, la lutte fongicide représente 80% des intrants. Un OAD (DeciTrait®) regroupant l’ensemble des informations nécessaires à la mise en œuvre d’une protection économe en intrants vis-à-vis des principales maladies cryptogamiques (mildiou - oïdium - black-rot - botrytis) a été conçu dans une démarche collaborative ausein d’un projet CASDAR. Cet OAD est simple à utiliser et propose à l’utilisateur une stratégie de protection personnalisée sur la base des informations et connaissances recueillies. Les essais biologiques conduits au sein du projet CASDAR mettent clairement en évidence le potentiel deréduction des intrants phytosanitaires permis par cet OAD, tant sur la réduction du nombre de traitements que sur la dose appliquée

Calcium and α-Tocopherol Suppress Cured Meat Promotion of Chemically-Induced Colon Carcinogenesis in Rats and Reduce Associated Biomarkers in Human Volunteers

Background: Processed meat intake is associated with increased colorectal cancer risk. We have shown that cured meat promotes carcinogen-induced preneoplastic lesions and increases specific biomarkers in the colon of rats. Objectives: To investigate whether cured meat modulates biomarkers of cancer risk in human volunteers, and whether specific agents can suppress cured meat induced preneoplastic lesions in rats, and associated biomarkers in rats and in humans. Design: Six additives (calcium carbonate, inulin, rutin, carnosol, α-tocopherol and trisodium pyrophosphate) were added to cured meat given to groups of rats for fourteen days, then fecal biomarkers were measured. Based on these results, calcium and tocopherol were kept for further experiments: cured meat, with or without calcium or tocopherol, was given to dimethylhydrazine-initiated rats (47% meat diet for 100 d), and to human volunteers in a cross-over study (180 g/d for 4 d). Rat colons were scored for mucin depleted foci, putative pre-cancer lesions. Biomarkers of nitrosation, lipoperoxidation, and cytotoxicity were measured in rats and volunteers’ urine and feces. Results: Cured meat increased nitroso-compounds and lipoperoxidation in humans stools (both P<0.05). Calcium normalized both biomarkers in rats and humans’ feces, while tocopherol only decreased nitro-compounds in rats and lipoperoxidation in volunteers’ feces (all p<0.05). Lastly, calcium and tocopherol reduced the number of mucin depleted foci per colon in rats compared with non supplemented cured meat (P=0.01). Conclusion: The data suggest that addition of calcium carbonate to the diet or of α-tocopherol to cured meat may reduce colorectal cancer risk associated with cured meat intake