The rate of oxygen uptake of quiescent papillary muscle of the cat heart has been determined in a flow respirometer with the use of the oxygen electrode. The apparent rate of oxygen uptake as a function of the diameter of the muscle was also determined. It was found that papillary muscles from cat hearts use oxygen at a rate of 2.84 (microliters/mg. wet weight)/hour at a temperature of 35 degre...

Oxygen transport from capillaries to exercising skeletal muscle is studied by use of a Krogh-type cylinder model. The goal is to predict oxygen consumption under conditions of high demand, on the basis of a consideration of transport processes occurring at the microvascular level. Effects of the decline in oxygen content of blood flowing along capillaries, intravascular resistance to oxygen dif...

Silver undergoes pronounced morphological changes following high-temperature treatment in various gas atmospheres. SEM analysis shows that high-temperature treatment in oxygen leads to pronounced facetting of the silver surface.In situXRD shows a strong texturing of the polycrystalline bulk and an expansion of the unit cell resulting from the dissolution of oxygen. Two distinctly different form...

Whole-body oxygen consumption is decreased after hemorrhage. Typical methods for increasing oxygen consumption have involved increasing the blood oxygen concentration using enriched oxygen gases, hemoglobins and fluorocarbon compounds; however, clinical trials involving these have not been totally successful. Increasing the oxygen concentration increases its diffusion rate through blood plasma;...

The measurement and evaluation of pulmonary function has been a difficult procedure. The common approach to this problem has been the crude method of judging pulmonary function by noting whether a subject shows evidence of dyspnea after exercise (walking up and down a ward or up a flight of stairs). This method is still the most frequent one employed in the majority of institutions where there ...

The activation of carbon monoxide by oxygen on Mg(100) surface has been investigated by X-ray photoelectron spectroscopy (XPS). Carbon monoxide is only weakly adsorbed (dispersion-type forces) on a magnesium surface. The XPS result has shown that the dissociation of carbon monoxide leading to the formation of a metastable surface carbonate species occurs through the participation of an oxyg...

Microplates with integrated optical oxygen sensors are a new tool to study metabolic rates and enzyme activities. Precise measurements are possible only if oxygen exchange between the sample and the environment is known. In this study we quantify gas exchange in plastic microplates. Dissolved oxygen was detected using either an oxygen-sensitive film fixed at the bottom of each well or a needle-...

Poly(vinyl alcohol) and polyethylene polymer systems were built in order to study their transport properties (diffusion). First a verification of the AMBER force field was conducted for a poly(vinyl alcohol) system built from a chain with 145 repeating units. NPT-molecular dynamics simulations at temperatures between 400 and 527 K were performed. The results of the simulations were compared wit...

Oxygen transport imposes a possible constraint on the brain's ability to sustain variable metabolic demands, but oxygen diffusion in the cerebral cortex has not yet been observed directly. We show that concurrent two-photon fluorescence imaging of endogenous nicotinamide adenine dinucleotide (NADH) and the cortical microcirculation exposes well-defined boundaries of tissue oxygen diffusion in t...