Influence of acid–base properties of cobalt–molybdenum catalysts supported on magnesium orthophosphates in isomerization of 3,3-dimethylbut-1-ene

AbstractSynthesis and physico-chemical characterization of a pure magnesium phosphate (MgP) prepared by coprecipitation, and MgP modified by introduction of cobalt–molybdenum (4–12wt.% of MoO3 with the Co/Mo ratio fixed at 0.5) have been carried out. The structural properties of these catalysts were characterized by X-ray diffraction, their textural properties were determined by N2 adsorption–desorption isotherms and the dispersion of cobalt–molybdenum was studied by XPS spectroscopy. Their acid properties have been investigated by in situ FT-IR spectroscopy of adsorbed molecules, often, 2,6-dimethylpyridine (pKa=6.7), pyridine (pKa=5.3). Co–Mo incorporation leads to a modification in the MgP acid–base properties, especially on the acid sites type and number. Thus, lower loading of cobalt–molybdenum species decreased the number of strong Lewis acid sites whereas higher loading increased it. It was found that Lewis acid sites on magnesium phosphates play an important role in the isomerization of 3,3-dimethylbut-1-ene.The 3,3-dimethylbut-1-ene (33DMB1) conversion increases with the reaction temperature from 493 to 653K for MgP, but decreases after 573K for MgP supported by Co–Mo. A linear relationship between both types of acid sites and conversion values was found. The deactivation of the catalysts appears at high reaction temperature (>573K)

BioGPS: an extensible and customizable portal for querying and organizing gene annotation resources

BioGPS is a community based customisable gene annotation portal bringing together gene annotation resources on to a single platform

Men’s artistic gymnastics: is the use of elastic surfaces systematic in the training process?

Abstract In Artistic Gymnastics, the area (the apparatus) represents the most relevant systemic component. Thus, when one strives to comprehend the internal logic of this sport, the gymnast-apparatus relationship warrants special attention. A change in the training paradigm was observed, showing that the use of Elastic Surfaces (ES) is an essential resource, due to the contemporary features of this sport, such as the hyper-valorisation of acrobatics and a greater presence of flight elements. Through a case study developed in a men’s artistic gymnastics high-performance gymnasium, this study analysed the use of different ES in the training process. Although coaches recognize the importance of ES in training programs, the record of daily activities showed that this use is still limited to select equipment and is not systematic. Such difficulties are due mainly to the lack of educational programs to the development of certain specific methodologies and the non-existence of national equipment suppliers certified by International Gymnastics Federation

A self-renewal assay for cancer stem cells

Cancers of epithelial origin are responsible for the majority of cancer-related deaths in the USA. Unfortunately, although chemotherapy and/or radiation therapy can sometimes shrink tumors, metastatic cancers of epithelial origin are essentially incurable. It is clear that new approaches are needed to treat these diseases. Although cancer cell lines provide invaluable information, their biological properties often differ in crucial ways from de novo cancer cells. Our laboratory has developed a novel mouse model that reliably permits individual cancer cells isolated directly from patients’ tumors to be assayed. This will allow the characterization of crucial signaling pathways involved in processes such as self-renewal that are critical for tumor formation by the cancer cells within de novo tumors. These tools should lead to new insights into the cellular and molecular mechanisms that drive human breast cancer growth and invasion.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46932/1/280_2005_Article_97.pd

La lutte antidopage : un problème d'éthique et de santé

Un état des lieux du dopage dans la gymnastique :liste des produits interdits, les controles antidopage et les sanctions infligée

Le furosémide

MIse en garde contre l'utilisation des produits diurétiques dont l'ingestion peut masquer celles de produits dopants dont on connaît les effets néfastes tant sur la santé du gymnaste que sur sa carrière sportive

Impact of copper and cadmium on aerobic and anaerobic digestibility of sonicated sludge

The effects of the introduction of a sludge reduction process such as ultrasound on batch aerobic and anaerobic biodegradability after exposition to two metals (copper and cadmium) were investigated. The specific energy of ultrasonic treatment applied to the sludge was 200,000 kJ kg TS-1. Ultrasonic treatment led to floc size reduction and to organic matter solubilization. Low copper (<5 mg L-1) and cadmium (<1 mg L-1) concentration improved aerobic biodegradability. For high metal concentration the maximal instantaneous biogas production rate qmax inhibition by copper and cadmium was modeled by a saturation-type relationship under aerobic and anaerobic conditions. Under aerobic conditions, respiration inhibition was not affected by sonication. Cadmium inhibition (74%) was more than copper (58%). The positive effect of sonication on CO2 production was maintained after metal introduction. Under anaerobic conditions, metal introduction cancelled out the positive effect of the treatment. The sonicated sludge was 16% less sensitive to copper inhibition but 10% more sensitive to cadmium inhibition compared to non sonicated sludge

"Culture visuelle et art collectif sur le web",

Sauvageot (éd.), Rapport intermédiaire, Ministère de la Culture, Direction aux Arts Plastique