Paul Sabatier University

About: Paul Sabatier University is a education organization based out in Toulouse, France. It is known for research contribution in the topics: Population & Adipose tissue. The organization has 15431 authors who have published 23386 publications receiving 858364 citations.

Numerical model of rf glow discharges.

Abstract: Theoretical predictions are given of the spatiotemporal distribution of charged-particle densities and electric field in a radio-frequency glow discharge. The model is based on a numerical solution of the continuity equations for electrons, positive ions, and negative ions coupled with Poisson's equation. The influence of frequency and gas composition (electropositive versus electronegative gas) on the discharge properties is analyzed and compared (qualitatively) with experimental results. In the case of electronegative gas mixtures, and at low frequencies (of the order and less than the ion plasma frequency), the numerical model predicts the formation of double layers at the plasma-sheath boundaries, in agreement with recent experimental measurements based on spectroscopic plasma-diagnostic techniques.

The Health Behaviour in School-aged Children: WHO Collaborative Cross-National (HBSC) Study: origins, concept, history and development 1982-2008

Abstract: This paper traces the history of the HBSC study from its origins in the early 1980’s to the present day describing how it was first conceptualised scientifically and how this influenced issues of study design. The challenges of managing a cross-national study are explained as are changes and adaptations over time with growth of the study from 3 to over forty country members. The key partnership with the World Health Organisation and its benefits are presented. With developments in scientific management and theoretical perspectives, HBSC has made a substantial contribution to the area of youth health. The last decade has seen increased dissemination to policy makers and evidence that scientific information arising from the study has influenced strategic policy development and practical health improvement programmes. This paper considers some of the key success factors and challenges for the study as it attempts to maximise its scientific output and channels the research findings into health improvement for young people. Future challenges for the study are also considered.

p21 binding to PCNA causes G1 and G2 cell cycle arrest in p53-deficient cells

Abstract: A unique feature of p21 that distinguishes it from the other cyclin-dependent kinase (CDK) inhibitors is its ability to associate with the proliferating cell nuclear antigen (PCNA), an auxiliary factor for DNA polymerases delta and epsilon. While it is now well established that inhibition of cyclin/CDK complexes by p21 can result in G1 cell cycle arrest, the consequences of p21/PCNA interaction on cell cycle progression have not yet been determined. Here, we show, using a tetracycline-regulated system, that expression of wild-type p21 in p53-deficient DLD1 human colon cancer cells inhibits DNA synthesis and causes G1 and G2 cell cycle arrest. Similar effects are observed in cells expressing p21CDK-, a mutant impaired in the interaction with CDKs, but not in cells expressing p21PCNA-, a mutant deficient for the interaction with PCNA. Analysis of cells treated with a p21-derived PCNA-binding peptide provides additional evidence that the growth inhibitory effects of p21 and p21CDK result from their ability to bind to PCNA. Our results suggest that p21 might inhibit cell cycle progression by two independent mechanisms, inhibition of cyclin/CDK complexes, and inhibition of PCNA function resulting in both G1 and G2 arrest.

Manipulation of lignin quality by downregulation of cinnamyl alcohol dehydrogenase

Abstract: The composition of lignin in tobacco stems has been altered by genetic engineering. Antisense expression of sequences encoding cinnamyl alcohol dehydrogenase (CAD), the enzyme catalysing the final step in lignin precursor synthesis, leads to the production of a modified lignin in otherwise normal plants. Although Klason and acetyl bromide lignin determinations show little quantitative change in lignin deposition in CAD antisense plants, a number of qualitative changes have been identified. The lignin is altered in both composition and structure and is more susceptible to chemical extraction. Consistent with a block in CAD activity, antisense plants incorporate less cinnamyl alcohol monomers and more cinnamyl aidehyde monomers into lignin than corresponding control plants. Antisense plants with very low levels of CAD activity also show a novel phenotype with the appearance of a red-brown colour in xylem tissues. A similar phenotype is correlated with altered lignification and improved digestibility in brownmidrib mutants of maize and sorghum. The improved chemical extractability of lignin in CAD antisense plants supports a role for this technology in improving the pulp and paper-making value of forest trees while the similarity with brown-midrib mutants suggests a route to more digestible forage crops.