The effects of sildenafil (Viagra) on hemodynamics and pulmonary gas exchange remain uncertain. The aim of this study was to investigate what effect sildenafil had on gas exchange. A total of 24 anesthetized pigs were randomly assigned into four groups of six animals each: Group Low received 25 mg of sildenafil, which is equivalent to half the recommended dose for humans; group Normal received ...

arterial blood gas parameters were analyzed in forty-nine healthy persons (31 males, 18 females) to detemine reference values fo these parameters and their relation to the time from last food intake to arterial puncture (t). the mean ± standard deviation of arterial oxygen pressure, arterial carbon dioxide pressure and ph at core body temperature were 84.4±7.0 mmhg (male: 83.0±6.5, female: 86.7...

The respiratory system of birds is structurally and functionally very different from that of mammals and has therefore attracted a great deal of interest. Briefly, the avian respiratory system consists of paired lungs, where gas exchange with the blood occurs, and of several large air sacs (grouped as anterior and posterior sacs) that act as bellows to move gases over the exchange surfaces of t...

The gill is widely accepted to have played a key role in the adaptive radiation of early vertebrates by supplanting the skin as the dominant site of gas exchange. However, in the most basal extant craniates, the hagfishes, gills play only a minor role in gas exchange. In contrast, we found hagfish gills to be associated with a tremendous capacity for acid-base regulation. Indeed, Pacific hagfis...

A recently developed quasi two-dimensional exact-exchange formalism within the framework of Density Functional Theory has been applied to a strongly inhomogeneous interacting electron gas, and the results were compared with state-of-the-art Variational Quantum Monte Carlo (VMC) numerical simulations for a three-dimensional electron gas under a strong external potential. The VMC results, extreme...

We describe a single flow transducer breath-by-breath gas exchange measurement system suitable for use during general anaesthesia. The system uses a Fleisch No. 2 pneumotachograph, a mass spectrometer and a microcomputer to give real-time continuous measurements. Correction for apparent gas exchange attributable to changes in gas stored in the lung (functional residual capacity) is available. T...

[1] Observation-based surface ocean DC distributions and regional inventories for excess, bomb-produced radiocarbon are compared with results of two ocean models of intermediate complexity. By applying current descriptions of the air-sea gas exchange the models produce similar column inventories for excess C among all basins. This result is robust across a wide range of transport parameter sett...

Z. Naturforsch. 43c, 709-716 (1988); received M a y 24, 1988 Chlorella, Oxygen Gas Exchange, Carbonic Anhydrase, Mass Spectrometry Oxygen gas exchange was monitored in the unicellular green alga Chlorella vulgaris 211 — 11 h by means of a mass spectrometer equipped with a special membrane gas-inlet-system and a photosynthetic reaction vessel. C02-dependent I802-uptake as well as ,602-evolution ...

change, CO2 concentrations, and refixation of respired CO2 in stands of Populus tremuloides Michx., Pinus banksiana Lamb. and Picea mariana (Mill.) B.S.P. at the northern and southern boundaries of the central Canadian boreal forest. Midsummer gas exchange rates in Populus tremuloides were over twice those of the two conifer species, and Pinus banksiana rates were greater than Picea mariana rat...