drought is an important abiotic stress limiting plant performance. generation of reactive oxygen species (ros) is enhanced under stresses. two greenhouse experiments were conducted to evaluate the effect of phytohormones on the changes of antioxidant enzymes and carotenoids in petals of pot marigold (calendula officinalis l.) under drought stress. results showed that the activities of superoxid...

Reduced carbohydrate (CHO) availability after exercise has a potent influence on the regulation of substrate metabolism, but little is known about the impact of fat availability and/or energy deficit on fuel metabolism when dietary CHO availability is not reduced. The purpose of this study was to determine the influence of a postexercise energy deficit, independent of CHO availability, on plasm...

It has been more than 60 years since the discovery of the oxygen effect that empirically demonstrates the direct association between cell radiosensitivity and oxygen tension, important parameters in radiotherapy. Yet the mechanisms underlying this principal tenet of radiobiology are poorly understood. Better understanding of the oxygen effect may explain difficulty in eliminating hypoxic tumor ...

When current is drawn from a fuel cell, it is critical that the reacted oxygen is replenished rapidly by the air supply system to avoid stack starvation and damage. We first explain that in a stand-alone fuel cell, there is lack of control authority in avoiding excessive oxygen starvation during high current demand. In the hybrid configuration introduced in this paper, a small auxiliary power s...

Individuals who habitually breathe through the mouth are more likely than nasal breathers to have sleep disorders and attention deficit hyperactive disorder. We hypothesized that brain hemodynamic responses in the prefrontal cortex might be different for mouth and nasal breathing. To test this hypothesis, we measured changes in oxyhemoglobin and deoxyhemoglobin in the prefrontal cortex during m...

STUDY OBJECTIVES To determine predictors of neuropsychological functioning in patients with obstructive sleep apnea (OSA) and whether treatment with 2-week continuous positive airway pressure (CPAP) or supplemental oxygen would improve cognitive functioning. DESIGN Randomized placebo-controlled design. SETTING University-based clinical research center. PATIENTS Forty-six patients with unt...

Modelling and simulation of the oxygen-sag model are used to demonstrate the potential benefits of the application of user friendly numerical software packages in environmental engineering education and practice. The simulation is used to obtain the profiles of oxygen concentration, oxygen deficit, as well as de-oxygenation and re-oxygenation rates as function of distance for a steady river vel...

This study examined the effect of repetitive apnea on brain oxygen pressure in newborn piglets. Each animal was given 10 episodes of apnea, initiated by disconnecting them from the ventilator and completed by reconnecting them to the ventilation circuit. The apneic episodes were ended 30 sec after the heart rate reached the bradycardic threshold of 60 beats per min. The oxygen pressure in the m...