Fast magic-angle spinning proton NMR studies of polymers at surfaces and interfaces.

Solid-state proton NMR with fast magic-angle sample spinning has been used to study the structure and dynamics of polymers and the water interface in porous glass composites. The composites were prepared by photopolymerization of poly(ethyl acrylate) and other acrylate formulations in a high surface-area rigid glass matrix with 40-A interconnected pores. High resolution solid-state proton spectra were obtained for polymer films and composites with 15 kHz magic-angle sample spinning at temperatures above the polymer glass transition temperature. The solid-state proton spectra can be detected with high sensitivity and used to determine the composition of polymer and water filling the pores. These results and spin diffusion studies using 1H-29Si 2D heteronuclear correlation and wideline separation NMR show that the polymer fills the central 30 A of the pore, and that the remaining volume is filled with surface hydroxyl groups and water.

Effect of exercise conditioning on red blood cell volume and erythropoietin concentration in the beagle dog.

To determine if endurance conditioning has a stimulating effect on red blood cell and erythropoietin production, we exercised five beagle dogs on a motor-driven treadmill for 1 hour per day, 5 days per week, for 6 weeks at a speed near their maximal capability. Three additional beagles were kept in cages and served as nonconditioned controls. Endurance conditioning in these dogs produced no increase in red blood cell mass, serum erythropoietin concentration, or any other blood cell index measured. We conclude that this type of exercise conditioning does not produce the necessary stimulus for an increase in erythropoiesis.