Application of end-systolic pressure-volume and pressure-wall thickness relations in conscious dogs

The usefulness of end-systolic measures of ventricular function was compared with that of standard contractility indexes in conscious dogs. End-systolic relations between left ventricular pressure and volume and between pressure and wall thickness were analyzed in dogs previously instrumented with ultrasonic crystals. Progressive angiotensin infusions were used to generate computer-averaged pressure-volume and pressure-wall thickness loops. Both relations were linear in every study and highly reproducible.With low and high dose dobutamine, the end-systolic pressure-volume relations were significantly displaced, with increased slope and inconsistent changes in intercept. This relation was more useful than the ejection fraction for detecting contractility increases at different afterloads, but it showed no advantage over maximal left ventricular dP/dt at all ranges of preload and after-load. The end-systolic pressure-volume relations were insensitive for detecting mild decreases in inotropic state produced by propranolol, and maximal dP/dt was superior for detecting such mild acutely reduced contractility. The end-systolic pressure-wall thickness relations showed displacement with dobutamine, although slope and intercept changes were not significant; these relations did not detect mild decreases in contractility produced by propranolol.It is concluded that the end-systolic pressure-volume relation and a simplified end-systolic measure using pressure and wall thickness provide sensitive, load-independent and reproducible approaches for defining acute increases in left ventricular contractility in conscious animals. Maximal dP/dt was equally effective for defining these increases in contractility and more sensitive for detecting slight acute decreases in contractility

Optical simulations of the Virgo interferometer

Sudies based on information in the organizations could benefit from an information activity centered approach. Observation of how work and information, of how information and action are linked would provide different definition of information and enlarge the notion of mediation, thus providing an understanding of new trends in organization structuration

Optical simulations of the Virgo interferometer

Sudies based on information in the organizations could benefit from an information activity centered approach. Observation of how work and information, of how information and action are linked would provide different definition of information and enlarge the notion of mediation, thus providing an understanding of new trends in organization structuration

Thick and widened high quality heavily boron doped diamond single crystals synthetized with high oxygen flow under high microwave power regime

International audienceThe aim of this paper is to optimize the growth conditions of thick boron doped diamond single crystals, which requires the use of high microware power density to have high growth rate, in order to allow enlarging CVD deposited layers keeping both high boron doping level and high crystal quality. It is shown that the use of a high amount of oxygen (1 to 2%) in the gas phase leads to 1 mm lateral growth after the growth of 500 μm thick CVD diamond layer. Thus, the surface is increased from 10 mm² to 18 mm². The obtained films exhibit high crystal quality confirmed by Raman spectroscopy and confocal microscopy. Depending on the gas composition introduced in the reactor, the boron concentration varied between 5×1019 at/cm3 and 3×1020 at/cm3 as measured by SIMS