[1] In situ crystallography based on diamond anvil cells have been extended to the multimegabar regime. Temperatures in these experiments have crossed the 2500 K mark. Yet, current high pressure-temperature (PT) standards of calibration produce uncertainties that inhibit clear conclusions about phenomena of importance to planetary processes, e.g., the postperovskite transition in Earth’s mantle...

We tested the utility of a standard isolated, crystalloid-perfused, isovolumic rat heart preparation for studying ventricular metabolism in terms of the myocardial oxygen consumption-pressure-volume area (MVO2-PVA) relations. The end-systolic pressure-volume relations (ESPVRs) determined between volumes of 0.15 and 0.65 ml were fit equally well by linear and nonlinear regression analysis within...

Left ventricular performance in the isolated dog heart was observed in a preparation in which left ventricular pressure and volume could be monitored continuously while the ventricle contracted isobarically by compressing air into a large chamber. By suddenly reducing the orifice connecting the ventricle to the chamber a constant load was imposed on the ventricle, abruptly forcing it to develop...

The value for the slope of the left ventricular (LV) end-systolic pressure-dimension and pressure-volume relations has been proposed as a quantitative measure of the LV inotropic state. This measure of LV inotropic state is attractive because it is independent of preload and incorporates afterload. To investigate the sensitivity of the slope of these relations to alterations in contractile stat...

The study of two-phase fluid flow behavior in hydraulic structures such as pressurized flow tunnels, culverts, sewer pipes, junctions and other similar conduits is of great importance. A two-phase mixture flowing in a pipe can exhibit several interfacial geometries such as bubbles, slugs or films, depending on the fluid and hydrodynamic properties of flow. The main variables, giving rise to a v...

Positive-pressure ventilation (PPV) may affect left ventricular (LV) performance by altering both LV diastolic compliance and pericardial pressure (Ppc). We measured the effect of PPV on LV intraluminal pressure, Ppc, LV volume, and LV cross-sectional area in 17 acute anesthetized dogs. To account for changes in lung volume independent of changes in Ppc and differences in contractility, measure...

Study of left ventricular pressure-volume relations in man has been limited by technical problems associated with left ventricular angiography. A new approach to this problem using simultaneous recording of left ventricular pressure and left ventricular volume (determined by echocardiography) was applied in 21 patients. Pressure-volume plots, constructed from pressure and volume values sampled ...

We predicted the shape of the end-systolic pressure-thickness relationship (ESPTR) by modeling the left ventricle as thick-walled sphere. To test the validity of the predicted relationships, we then measured the ESPTR over wide volume ranges in seven isolated blood-perfused canine hearts. Both simulation and experiments demonstrated that the ESPTR is curvilinear. However, within a physiological...

The present study was intended to define the interrelation among endocardial flow, endocardial function, and coronary arterial pressure during spontaneous autoregulation in the left ventricle of chronically instrumented unanesthetized dogs. Steady-state sonomicrometric measurements of regional function and epicardial coronary artery pressure were used to determine the lower pressure limit of en...

We obtain several combinatorial results about chains, cycles and orbits of the elements of the symmetric inverse semigroup ISn and the set Tn of nilpotent elements in ISn. We also get some estimates for the growth of |ISn| and |Tn|, and study random products of elements from ISn.