The lungs move air in and out like bellows. Fresh, oxygen-rich air mixes with intrapulmonary air. Oxygen is carried with the circulation and carbon dioxide is excreted with the exhaled air. Various mechanisms maintain the purposeful distribution of ventilation and circulation. Very much of the complicated physiology and pathophysiology is already known, and it has recently become possible to ob...

Decompression sickness (DCS) after air diving has been treated with success by means of combined normobaric oxygen breathing and intravascular perfluorocarbon (PFC) emulsions causing increased survival rate and faster bubble clearance from the intravascular compartment. The beneficial PFC effect has been explained by the increased transport capacity of oxygen and inert gases in blood. However, ...

OBJECTIVE To compare the efficacy of low-flow oxygen, low-flow air and sham treatment given via nasal cannulae in preventing desaturation (falls in oxygen saturation (SpO2)) in preterm infants. STUDY DESIGN Infants born at <33 weeks gestation receiving gas at flow rates <1 l/min via nasal cannulae were eligible for inclusion. Enrolled infants received three treatments-0.1 l/min 100% oxygen, 0...

We sought to define the role of hypoxemia in eliciting the cardiovascular responses to apnea during exercise. Eleven men performed repeated apneas during 100-W steady-state exercise, either with normoxic gas (air) or 95% oxygen (oxygen). Beat-by-beat arterial blood pressure, arterial oxygen saturation, and heart rate (HR) were determined, and stroke volume (SV) was estimated from impedance card...

STUDY OBJECTIVE To determine whether nasal oxygen therapy at 2 L/min would (1) reverse nocturnal hypoxemia and (2) improve neuropsychologic function in men who snore heavily. DESIGN To select heavy-snoring subjects for a treatment protocol, volunteers were screened for one night, breathing air the first half and oxygen the second half of the night. If nocturnal oxygen desaturation occurred in...

In this research the simulation of an air independent Proton Exchange Membrane Fuel Cell (PEMFC) propulsion system was taken into consideration. The system consists of several parts including PEM fuel cell stack, metal hydride and liquid oxygen (LOX) tanks, and also pre-heaters of oxygen and hydrogen gases along with other heat exchangers, to ensure proper operation of system. The heat recovery...

Increase in air or oxygen pressure in microbial cell cultures can cause oxidative stress and consequently affect cell physiology and morphology. The behaviour of Saccharomyces cerevisiae grown under hyperbaric atmospheres of air and pure oxygen was studied. A limit of 1.0 MPa for the air pressure increase (i.e. 0.21 MPa of oxygen partial pressure) in a fed-batch culture of S. cerevisiae was est...

Large numbers of people live or work at high altitude, and many visit to trek or ski. The inevitable hypoxia impairs physical working capacity, and at higher altitudes there is also cognitive impairment. Twenty years ago oxygen enrichment of room air was introduced to reduce the hypoxia, and this is now used in dormitories, hotels, mines, and telescopes. However, recent advances in technology n...

Group-living is widespread among animals and comes with numerous costs and benefits. To date, research examining group-living has focused on trade-offs surrounding foraging, while other forms of resource acquisition have been largely overlooked. Air-breathing has evolved in many fish lineages, allowing animals to obtain oxygen in hypoxic aquatic environments. Breathing air increases the threat ...

We have studied the passage of oxygen through the pulmonary epithelium during progressively induced anoxemia.’ The dog is remarkably resistant to the effects of a lowered oxygen tension in the inspired air. He will maintain both respiration and an adequate circulation when breathing air containing from 3 to 4 per cent of oxygen. Man, on the other hand, becomes unconscious or “faints” when the o...