Cinematic reflectometry using QIKR, the quite intense kinetics reflectometer.

The Quite Intense Kinetics Reflectometer (QIKR) will be a general-purpose, horizontal-sample-surface neutron reflectometer. Reflectometers measure the proportion of an incident probe beam reflected from a surface as a function of wavevector (momentum) transfer to infer the distribution and composition of matter near an interface. The unique scattering properties of neutrons make this technique especially useful in the study of soft matter, biomaterials, and materials used in energy storage. Exploiting the increased brilliance of the Spallation Neutron Source Second Target Station, QIKR will collect specular and off-specular reflectivity data faster than the best existing such machines. It will often be possible to collect complete specular reflectivity curves using a single instrument setting, enabling "cinematic" operation, wherein the user turns on the instrument and "films" the sample. Samples in time-dependent environments (e.g., temperature, electrochemical, or undergoing chemical alteration) will be observed in real time, in favorable cases with frame rates as fast as 1 Hz. Cinematic data acquisition promises to make time-dependent measurements routine, with time resolution specified during post-experiment data analysis. This capability will be deployed to observe such processes as in situ polymer diffusion, battery electrode charge-discharge cycles, hysteresis loops, and membrane protein insertion into lipid layers.

Ejection fraction and regional wall motion at rest and during stress in the diagnosis of coronary artery disease.

Stress radio nuclide ventriculography is used to determine ejection fraction and changes in regional wall motion for the detection of ischemia-induced left ventricular dysfunction in patients with coronary artery disease. We have evaluated the relative sensitivity of regional wall motion and of ejection fraction during hand-grip and cold pressor test, in 21 patients with angina pectoris and documented coronary artery disease at angiography. Regional wall motion appeared a more sensitive index than global ejection fraction producing only two false negative cases. Ejection fraction showed great variability among the patients during both hand-grip and cold pressor test. This might be explained by the fact that both tests do not produce a sufficient degree of ischemic stress on the left ventricle. Hand-grip and cold pressor tests appear useful alternative to dynamic exercise in the diagnosis of coronary artery disease being also safe and simple to perform.