Oxygen delivery and consumption after hemodilution with a perfluorocarbon-based oxygen carrier (PFCOC) was evaluated at sea level and at 2,600 m above sea level. Fifteen anesthetized rats were subjected to a two-exchange normovolemic hemodilution of 40% of the circulating blood volume each. First exchange was performed with a colloid solution. Second exchange was with 80% PFCOC and 20% colloid....

In a study of the oxygen stores of the body anaesthetized paralyzed dogs were hyperventilated (Pa<x), = 15 mm Hg) for 2 hours. During the final 30 minutes the inspired mixture was altered from oxygen to air. The rates at which alveolar and arterial oxygen concentrations approached their new steady-state values were represented by the halftimes (t£) 0.17 and 0.23 minutes respectively. The turnov...

The regulation of the pacing strategy remains poorly understood, because much of classic physiology has focused on the factors that ultimately limit, rather than regulate, exercise performance. When exercise is self-paced and work rate is free to vary in response to external and internal physiological cues, then a complex system is proposed to be responsible for alterations in exercise intensit...

Blood oxygen level dependent (BOLD) signals characteristically exhibit an overshoot (transient signal increase) at the beginning of fMRI task blocks. This onset transient has often been overlooked as an independent measure of neuronal activity, but it may represent unique functional processes. We examined onset transient responses in normal subjects and individuals with schizophrenia performing...

In a recent commentary, Dorjee and Bowers (2012) raise several issues concerning the interpretation of functional MRI (fMRI) studies that examine learning in general and perceptual learning in particular. The authors rightly criticize an implicit assumption that differences in blood oxygen level dependent (BOLD) levels before and after training can be used to exhaustively determine the brain ar...

Photoexcitation experiments performed in oxygen deficient but metallic YBa,Cu,O, c-axis oriented films revealed that the persistent photoinduced enhancement of conductivity and superconductivity are not restricted to the insulating side of the metal-insulator transition. A clear increase of the critical temperature T,, which is accompanied by a decrease of the resistivity in the normal state pa...

Blood oxygen level-dependent (BOLD) MRI data of kidney, while indicative of tissue oxygenation level (Po2), is in fact influenced by multiple confounding factors, such as R2, perfusion, oxygen permeability, and hematocrit. We aim to explore the feasibility of extracting tissue Po2 from renal BOLD data. A method of two steps was proposed: first, a Monte Carlo simulation to estimate blood oxygen ...

What helps us determine whether a word is a noun or a verb, without conscious awareness? We report on cues in the way individual English words are spelled, and, for the first time, identify their neural correlates via functional magnetic resonance imaging (fMRI). We used a lexical decision task with trisyllabic nouns and verbs containing orthographic cues that are either consistent or inconsist...