Etude du système ternaire Cd-Sb-Zn ; élaboration et caractérisation du composé thermoélectrique Zn4Sb3

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Rapport de synthèse de mission en Malaisie et Indonésie

Après leur participation à l'"International Cocoa Conference Challenges in the 90s", les auteurs ont visité les principaux centres de recherche en agronomie et technologie du café et du cacao afin d'évaluer les possibilités de coopération avec l'IRCC. Les thèmes retenus sont les suivants : 1) en Malaisie, le Malaysian Cocoa Board : évolution des précurseurs d'arôme au cours de la fermentation et du séchage du cacao; le Felda (Tun Razak) : traitement post récolte du café Liberica, traitement correct du cacao avec diminution des coûts de production; 2) en Indonésie, le RISPA (Medan) : contrôle de la qualité du cacao; le centre de recherches de Jember : agronomie et technologie du cacao et des cafés Robusta et Arabica; le centre de Bogor : scolyte du grain de café et fertilisation du cacaoyer; le groupe Hasfarm : café Arabica; la société Malabar Makmur : fourniture de matériel végétal de caféier Arabica et la société Multi-Agro : technologie du caca

Archéologie de la forêt charbonnée : questions et méthodes, illustrées par I'exemple du site de Lercoul (Ariège)

International audienceL'archéologie des forets charbonnées que nous pratiquons a pour objectif de restituer la dynamique des peuplements sur le long terme. La question principale concerne la représenta­tivité des charbonnières étudiées, notamment en fonction des pratiques des charbonniers

Raman scattering study of the lattice dynamics of β-Zn4−xCdxSb3

Micro-Raman scattering experiments have been performed on the ternary solid solution in the Zn4Sb3–Cd4Sb3 system. Ten samples were studied; their compositions go from Zn4Sb3 to Zn3.1Cd0.9Sb3. The homogeneity of these samples was checked by X-ray diffraction and electron microprobe analysis. The corresponding lattice parameters were calculated and their concentration dependence exhibits a small negative deviation from Vegard's law between end members of the Zn4Sb3–Cd4Sb3 system. Three peaks and one shoulder are easily observable in the Raman spectrum of β-Zn4Sb3. These peaks are still present when the zinc atoms are substituted by cadmium ones. As the intensities of the Raman lines were observed to be very sensitive to the direction of the microcrystallites, only the change of the position could be discussed. From these experiments, we can suggest that the peak at about 155 cm−1 should imply essentially Sb–Sb bondings while the peaks at about 172 cm−1 and 320 cm−1 must also imply Cd–Sb and Zn–Sb bondings

Design of distributed space-time trellis code for relay systems with cascaded nakagami channels

Due to copyright restrictions, the access to the full text of this article is only available via subscription.Bu çalışmada, tek roleli, işbirlikli ve kodlamalı bir sistemin kanallarının kaskat Nakagami dağılımlı olması durumundaki hata performans analizi yapılmıştır. Sistemin genel çiftsel hata olasılığı üst sınırı kullanılarak dağıtılmış uzay-zaman kodlar için kod tasarım ölçütü belirlenmiş ve bu ölçüt kullanılarak 4-PSK ve 8-PSK modülasyonları için 8 durumlu dağıtılmış uzay-zaman kafes kodları tasarlanmıştır. Tasarlanan kodların hata performansları bilgisayar benzetimi ile değerlendirilmiş ve referans alınan kodlarınki ile karşılaştırılmıştır.TÜBİTA

Inhibitory effects of trans-resveratrol analogs molecules on the proliferation and the cell cycle progression of human colon tumoral cells.

International audienceResveratrol may function as a cancer chemopreventive agent. However, few data are available on the antitumoral activities of its dimer, epsilon-viniferin, also present in human diet. So, the effects of resveratrol, epsilon-viniferin, of their acetylated forms (resveratrol triacetate, epsilon-viniferin pentaacetate) and of vineatrol (a wine grape extract) were compared on human adenocarcinoma colon cells. Resveratrol and resveratrol triacetate inhibit cell proliferation and arrest cell cycle. epsilon-Viniferin and epsilon-viniferin pentaacetate slightly reduce cell proliferation. Vineatrol inhibits cell proliferation and favors an accumulation in the S phase of the cell cycle. Consequently, resveratrol triacetate and vineatrol could constitute new putative anticancer agents on colon carcinoma

Bioactive stilbenes from Vitis vinifera grapevine shoots extracts.

Vitis vinifera grapevine shoots are potentially interesting as a source of new bioactive stilbenes, such as vitisinol C. © 2013 Society of Chemical Industry

Effects of resveratrol analogs on cell cycle progression, cell cycle associated proteins and 5fluoro-uracil sensitivity in human derived colon cancer cells.

International audienceEpidemiological studies suggested that trans-resveratrol, a wine grape component, could prevent malignant tumor development. This compound also demonstrated cytostatic and cytotoxic effects on tumor cells in vitro. To obtain trans-resveratrol derivatives with a better cellular uptake and enhanced antiproliferative effects, we synthesized a triacetate derivative as well as an oligomer, epsilon-viniferin and its acetylated form, epsilon-viniferin penta-acetate. We also obtained vineatrol, a wine grape shoot extract that associates several polyphenols that may act synergistically, including trans-resveratrol and epsilon-viniferin. We show here that resveratrol triacetate and vineatrol are as efficient as trans-resveratrol in inducing the accumulation of human colon cancer cells in early S phase of the cell cycle. This effect is associated with a nuclear redistribution of cyclin A and the formation of a cyclin A/cyclin-dependent kinase 2 complex whose kinase activity is increased. In contrast, epsilon-viniferin and its acetylated form do not demonstrate any significant activity on these cells when tested alone. Interestingly, resveratrol triacetate and vineatrol dramatically enhance 5-Fluoro-Uracil-mediated inhibition of colon cancer cell proliferation. Thus, acetylated derivatives of resveratrol have retained the cytostatic and cytotoxic activities of the parental molecule and thus deserve to be tested as chemosensitizers in animal models

Chefs et Rois sacrés

Le laboratoire « Systèmes de Pensée en Afrique noire » propose ici de soumettre à un éclairage nouveau le modèle classique des « rois divins » défini jadis par Frazer. Qu'on le considère comme un "corps-fétiche", qu'il se présente comme un "roi-prêtre", ou comme un "chef sacré", le roi, par son intronisation, acquière des propriétés uniques, qui sont discutées ici dans le détail et sous une grande variété de formes. Toutes ces variations tournent néanmoins autour de la même question: que faire d'un être unique chargé d'articuler l'ordre social et l'ordre naturel? Est-il placé au cœur de la société ou en dehors? Ou à la fois en-dedans ou en dehors