Diving-related pulmonary effects are due mostly to increased gas density, immersion-related increase in pulmonary blood volume, and (usually) a higher inspired Po(2). Higher gas density produces an increase in airways resistance and work of breathing, and a reduced maximum breathing capacity. An additional mechanical load is due to immersion, which can impose a static transrespiratory pressure ...

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...

Membranes have emerged as an attractive approach to separating materials in many industries, from medical to chemical to water. When formed into hollow fiber tubes, membranes deliver highly efficient operation in a small footprint. The advantages are numerous: low energy requirements, simplicity of operation, and high specificity. This paper explains the principles behind membrane transport and...

Exchange of gases, such as O2, CO2, and CH4, over the air–water interface is an important component in aquatic ecosystem studies, but exchange rates are typically measured or estimated with substantial uncertainties. This diminishes the precision of common ecosystem assessments associated with gas exchanges such as primary production, respiration, and greenhouse gas emission. Here, we used the ...

The theory that birds evolved from a group of small terrestrial theropod dinosaurs has created much controversy. One argument proposed against this theory is that the lungs of early theropods were incapable of sustaining endothermic gas exchange requirements and could not have given rise to the lungs of birds. A reexamination of the comparative physiological and morphological literature combine...

Pentoxifylline is a xanthine derivative with hemorrheologic and vascular properties that may improve gas exchange in patients with chronic obstructive pulmonary disease (COPD). We tested this hypothesis in 12 patients with COPD (mean FEV1 = 40 percent predicted; mean DCO, 8.6 ml/min/mm Hg) randomly divided into a treatment and control group and six healthy volunteers. Following establishment of...

In clinical practice, the mechanical ventilation is a very important aided method to improve patients' breath, so parameter setting of ventilator directly affects pulmonary gas exchange. In this report, we try to build a decision support system based on the gas exchange model for mechanical ventilation using fuzzy logic. The gas exchange mathematic model can simulate individual patient's pulmon...

Previously, it has been suggested that insect gas exchange cycle frequency (fC) is mass independent, making insects different from most other animals where periods typically scale as mass-0.25. However, the claim for insects is based on studies of only a few closely related taxa encompassing a relatively small size range. Moreover, it is not known whether the type of gas exchange pattern (disco...

The solvent exchange procedure has become the most-used protocol to produce surface nanobubbles, while the molecular mechanisms behind the solvent exchange are far from being fully understood. In this paper, we build a simple model and use molecular dynamics simulations to investigate the dynamic characteristics of solvent exchange for producing nanobubbles. We find that at the first stage of s...