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Carbon and chromium surfaces were modified by electrochemical reduction of a diazonium salt formed in situ from the sulfanilic acid. The organic layer formed was activated by phosphorus pentachloride (PCl(5)) to form a benzene sulfonil chloride (Ar-SO(2)Cl). An electrochemical study of the blocking effect and the activity of this surface was carried out on a carbon electrode. The chromium surface study was completed by X-ray photoelectron spectroscopy and atomic force microscopy to characterize the formation of a compact monolayer (0.8 nm height and roughness 0.2-0.3 nm). The compactness and the activity of this organic monolayer allowed us to affix a length dsDNA with the aim of analyzing the formation of a complex between dsDNA and a protein. The interaction of a transposase protein with its target dsDNA was investigated. The direct imaging of the nucleoproteic complex considered herein gives new insights in the comprehension of transposase-DNA interaction in agreement with biochemical data.

The aim of the current research was to investigate the relative age effect as a factor of basketball dropout. In order to do so, we examined the distribution of birth dates of young male (n = 44,498) and female (n = 30,147) French basketball players who have dropped out this sport during or at the end of the 2005-2006 season. Chi-square analyses showed an underrepresentation of dropouts among male players born early in the competition year and an overrepresentation among those born late in the ‘9-10 years old', ‘11-12 years old' and ‘13-14 years old' categories and in the first year of the ‘15-17 years old' category. Concerning girls, this asymmetry was observed across the same age categories. For both boys and girls, there was no biased distribution in the ‘7-8 years old' category. Findings of the present study confirm that the relative age effect should be taken into consideration in studies about sport dropout as a variable that may influence significantly this phenomenon.

The relative age effect (RAE) is a biased distribution of elite athletes’ birthdates, with an overrepresentation of those born at the beginning of the competitive year and an underrepresentation of those born at the end. Despite an abundant literature, the impact of sex on this phenomenon remains neglected by most researchers. This study investigated the whole sample of female soccer players affiliated to the French Soccer Federation for the 2006–2007 season (n 5 57 892). It first aimed at testing the presence of RAE depending on age. Next, we looked at the birthdates of dropout players during the next season (n 5 15 285), to test whether relative age accounts for dropout from the activity. The analyses revealed significant differences between the expected and the observed distributions for all age categories. Furthermore, a significantly biased distribution of dropout players’ birthdates was found for the o10, o14, and o17 categories. On the whole, dropout players are underrepresented in Q1 and Q2, but overrepresented in Q3 and Q4. This study completes the literature on RAE among females, but the inconsistency of the results calls for more research on this population. The relative age effect (RAE) is a phenomenon initially observed by Grondin et al. (1984), and consists in a biased distribution of elite players’ birthdates. What is generally noticed is an overrepresentation of athletes born at the beginning of the competitive year but an underrepresentation of people born by the end of it. It is considered to be derived from the age categories distinguished by sport instances to organize and try to balance youth competition. Most of the time, children and adoles

The aim of this study is to test the presence of the relative age effect (RAE) and to examine height in an overall population of the young French basketball players from 7 to 18 years old, male (n=151 259) and female (n=107 101). For the boys as for the girls, the results show a statistically significant RAE in all age categories. The effect seems more pronounced during puberty. As far as the height is concerned, players born during quarters 1 and 2 are always significantly taller than those born during quarter 4, apart from the 17-year-old female players. These results require a new look at the methodology in the statistical calculation and the interpretation of RAE. A study wanting to give a precise measurement of this effect will have to take as the expected theoretical distribution the whole population of licensed players in the corresponding years, rather than one on the global population of the country. This will avoid the hasty conclusion that an asymmetric distribution of dates of birth of professional players would be due to RAE, whereas in reality it would be representative of one existing in the population of licensed players.

There has been experimental evidence that lung distension produces an increase in pulmonary vascular resistance (PVR). To study this effect in patients, we measured functional residual capacity (FRC) by helium dilution at rest and during low-load supine exercise in 30 patients with chronic obstructive pulmonary disease. Pulmonary haemodynamics were studied in these patients under the same conditions. FRC increased from rest (4.32 +/- 0.21 l) to exercise (4.71 +/- 0.20, P less than 0.001) but the change was smaller in the patients with the highest FRC at rest: there was a significant negative correlation between FRC change and FRC at rest (r = -0.38, P less than 0.01). There were seven patients with a small FRC change (less than 0.2 l) with exercise and 10 patients with a marked increase (greater than 0.5 l). Exercise was of the same load on average. FRC at rest was 5.1 l in the first group and 4 l in the second (P less than 0.05). Blood gases were almost identical at rest, and almost unchanged during exercise. PVR decreased from rest to exercise by 33 dyn.s.cm-5 in the first group and increased by 24 in the second (P less than 0.01). There was a significant correlation (P less than 0.05) between PVR and FRC changes from rest to exercise. These results suggest that lung distension may play a role in the PVR increase seen in some COPD patients with exercise.