Macromolecules such as hemoglobin exert both kinetic and matrix effects on osmotic pressure. The kinetic osmotic pressure of sickle-cell hemoglobin is lost upon deoxygenation at physiological erythrocyte concentrations. The non-kinetic or matrix component of osmotic pressure remains relatively unchanged. Loss of thermal-osmotic activity during deoxygenation occurs throughout a hemoglobin concen...

The purpose of this study was to determine whether acute hypoxia alters the deoxygenation level in vastus lateralis muscle during a 30 s Wingate test, and to compare the muscle deoxygenation level between sprint athletes and untrained men. Nine male track sprinters (athletic group, VO2max 62.5 ± 4.1 ml/kg/min) and 9 healthy untrained men (untrained group, VO2max 49.9 ± 5.2 ml·kg(-1)·min(-1)) pe...

PURPOSE This study evaluated heterogeneity of muscle O2 dynamics in a single muscle during bicycle exercise using an eight-channel near-infrared continuous wave spectroscopy (NIRcws) mapping system. METHODS Nine healthy subjects performed bicycle exercise at fixed workloads of 20, 40, 60, 80, and 100% maximal workload for 5 min at each level. Muscle oxygenation in the vastus lateralis (VL) du...

1. The kinetics of oxygen transfer across the water-blood barrier in fish gills were studied by measuring oxygenation and deoxygenation of single red blood cells contained within isolated secondary lamellae using a microphotometric technique. 2. Recordings of the overall time courses show that both oxygenation and deoxygenation are more rapid in the carp than in the eel. In both species the hal...

Phosphatidylserine exposure occurs in red blood cells (RBCs) from sickle cell disease (SCD) patients and is increased by deoxygenation. The mechanisms responsible remain unclear. RBCs from SCD patients also have elevated cation permeability, and, in particular, a deoxygenation-induced cation conductance which mediates Ca(2+) entry, providing an obvious link with phosphatidylserine exposure. The...

A simple method has been developed for the reductive deoxygenation of aromatic ketones and benzylic alcohols in the presence of polymethylhydrosiloxane (PMHS). The reductive deoxygenation of aromatic ketones and benzylic alcohols, including secondary alcohols, to the corresponding methylene hydrocarbons has been achieved in good to excellent yields using palladium chloride (PdCl2) as catalyst a...

Reductions in prefrontal oxygenation near maximal exertion may limit exercise performance by impairing executive functions that influence the decision to stop exercising; however, whether deoxygenation also occurs in motor regions that more directly affect central motor drive is unknown. Multichannel near-infrared spectroscopy was used to compare changes in prefrontal, premotor, and motor corti...

To assess the role of intracellular hemoglobin concentration in the deformability of sickle (HbSS) cells after deoxygenation, rheologic coefficients (static rigidity E and dynamic rigidity eta) of density-fractionated individual sickle erythrocytes (SS cells) were determined as a function of oxygen tension (pO2) using the micropipette technique in a newly developed experimental chamber. With st...

Deoxygenation of a secondary hydroxy group on β-cyclodextrin was conducted to prepare the title compound 2II-VII, 3I-VII, 6I-VII-icosa-O-acetyl-2I-deoxy-cyclomaltoheptaose. The synthetic procedure comprised a two-step reaction—phenoxythiocarbonylation and Barton-McCombie deoxygenation. The synthesized compound was characterized by 1H-NMR, 13C-NMR, HRMS, and elemental analysis.

The rates of marine deoxygenation leading to Cretaceous Oceanic Anoxic Events are poorly recognized and constrained. If increases in primary productivity are the primary driver of these episodes, progressive oxygen loss from global waters should predate enhanced carbon burial in underlying sediments-the diagnostic Oceanic Anoxic Event relic. Thallium isotope analysis of organic-rich black shale...