Iron can be a detrimental catalyst in biological free radical oxidations. Because of the high physiological ratio of [O2]/[H2O2] (> or = 10(3)), we hypothesize that the Fenton reaction with pre-existing H2O2 is only a minor initiator of free radical oxidations and that the major initiators of biological free radical oxidations are the oxidizing species formed by the reaction of Fe2+ with dioxyg...

Stimulation of granulocyte (PMN) superoxide (O2-) production by concanavalin-A (Con-A) can be monitored continuously in the spectrophotometer. Both the rate of activation and final activity of the O2--generating system is dependent on the concentration of Con-A. Alpha methylmannoside (alpha MM) can prevent Con-A, but not phorbol myristate acetate (PMA) or zymosan, induced O2- production. Alpha ...

Thirteen patients with ischemic coronary heart disease purposely hyperventilated for seven minutes in order to induce hypocapnic alkalosis. One patient experienced chest pain, and one exhibited chemical signs of myocardial hypoxia. Heart rate, blood pressure and myocardial O2 consumption did not change significantly. Coronary blood flow decreased and coronary (a-v)O2 difference widened. Since t...

Contributions of intermolecular electron energy transfers in the electronic quenching are calculated for molecular collisions N2(A6 u , W 1u)+N2(X6 g , v=0), N2(A6 u )+N2(X 16+ g , v≥0), N2(A 36+ u )+O2(X 36− g , v=0– 2), O2(a1g , b16+ g )+O2(X 36− g , v=0–2). The calculation has allowed one to estimate the product branching ratios. It is shown that there is a dependence of the calculated rate ...

The effect of arterial O2 content (Ca(O2)) on quadriceps fatigue was assessed in healthy, trained male athletes. On separate days, eight participants completed three constant-workload trials on a bicycle ergometer at fixed workloads (314 +/- 13 W). The first trial was performed while the subjects breathed a hypoxic gas mixture [inspired O2 fraction (Fi(O2)) = 0.15, Hb saturation = 81.6%, Ca(O2)...

In polycystic ovary syndrome (PCOS), cardiovascular risk is increased. Peak O2 uptake (V˙O2peak) predicts the cardiovascular risk. We were the first to examine the contribution of systemic O2 delivery and arteriovenous O2 difference to V˙O2peak in overweight and obese women with PCOS. Fifteen overweight or obese PCOS women and 15 age-, anthropometry-, and physical activity-matched control women...

During contractions, regulation of microvascular oxygen partial pressure (Pmv(O2)), which drives blood-myocyte O2 flux, is a function of skeletal muscle fiber type and oxidative capacity and can be altered by exercise training. The kinetics of Pmv(O2) during contractions in predominantly fast-twitch muscles evinces a more rapid fall to far lower levels compared with slow-twitch counterparts. Pe...

The results of an experimental study of the combustion of single aluminum particles in N2/O2, Ar/O2, and He/O2 gas mixtures, and in pure O2 are presented and interpreted. This research focuses on identifying conditions under which asymmetric combustion of the aluminum particles develops. It also illustrates the relationship between aluminum particle combustion behavior and particle internal and...

To determine whether conditions for O2 utilization and O2 off-loading from the hemoglobin are different in exercising arms and legs, six cross-country skiers participated in this study. Femoral and subclavian vein blood flow and gases were determined during skiing on a treadmill at approximately 76% maximal O2 uptake (V(O2)max) and at V(O2)max with different techniques: diagonal stride (combine...

An extensive photoelectron spectroscopic study on the CuOx (x ) 0-6) species is presented. The photoelectron spectra of these species are obtained at four detachment photon energies: 2.33, 3.49, 4.66, and 6.42 eV. The spectra of the copper atom are included to show the dependence of the detachment cross sections on the photon energies. An intense two-electron transition to the 2P excited state ...