Theoretical Study on the Noble Gas Exchange Reactions of Ng + HNBNg′+ → Ng′ + HNBNg+ (Ng, Ng′ = He, Ne, Ar, Kr, and Xe)

2015 ◽  
Vol 120 (8) ◽  
pp. 1780-1787 ◽  
Author(s):  
Cheng-Cheng Tsai ◽  
Po-Chun Liu ◽  
Wei-Ping Hu
Keyword(s):  
Gas Exchange ◽  
Theoretical Study ◽  
Noble Gas ◽  
Exchange Reactions

Effect of change in P50 on exercise tolerance at high altitude: a theoretical study

1982 ◽  
Vol 53 (6) ◽  
pp. 1487-1495 ◽  
Author(s):  
H. Z. Bencowitz ◽  
P. D. Wagner ◽  
J. B. West
Keyword(s):  
Gas Exchange ◽  
Exercise Tolerance ◽  
Theoretical Study ◽  
Dissociation Curve ◽  
Diffusion Limitation ◽  
Rightward Shift ◽  
Arterial Po2 ◽  
O2 Dissociation Curve ◽  
Very High ◽  
Alveolar Capillary

Acclimatization to altitude often results in a rightward shift of the O2 dissociation curve (ODC). However, a left-shifted ODC is reported to increase exercise tolerance in humans at medium altitude and increase survival in rats breathing hypoxic gas mixtures. We examined this paradox using a computer model of pulmonary gas exchange. A Bohr integration procedure allowed for alveolar-capillary diffusion. When diffusion equilibration was complete, mixed venous (PVO2) and arterial PO2 fell as O2 consumption (VO2) was increased, but PVO2 approached a plateau. Under these conditions a right-shifted ODC is advantageous (higher PVO2) at all but very high altitudes. However, diffusion limitation of O2 transfer may occur at any altitude if VO2 is increased sufficiently. If this occurs, a left-shifted ODC results in higher calculated VO2max (compared with the standard ODC). Further, diffusion limitation always occurs at a lower VO2 with a right-shifted ODC than with a left-shifted ODC. We conclude that whether a leftward or rightward shift in the ODC is advantageous to gas exchange at altitude depends on the presence or absence of diffusion limitation.

Effect of altered gas diffusivity on alveolar gas exchange-a theoretical study

1980 ◽  
Vol 48 (1) ◽  
pp. 147-153 ◽  
Author(s):  
W. Nixon ◽  
A. Pack
Keyword(s):  
Blood Flow ◽  
Gas Exchange ◽  
Theoretical Study ◽  
Experimental Studies ◽  
Flow Distribution ◽  
Molecular Diffusivity ◽  
Gas Diffusivity ◽  
Experimental Findings ◽  
Lung Airways ◽  
Alveolar Gas Exchange

Experimental studies have established that alveolar gas exchange is inversely relation to the molecular diffusivity of gas in the lung airways. The mechanism underlying this relationship is, however, unclear. To investigate this phenomenon, the conditions relevant to the experimental studies are simulated using a computational model of pulmonary gas transport. Results from these simulations suggest that the inverse relationship found experimentally can largely be explained on the basis of the intra-acinar stratification of blood flow and gas concentrations. Gas having a relatively low molecular diffusivity is not transported as far into the acinus as gas having a higher diffusivity. When these relative intra-acinar gas distributions interact with the blood flow distribution, which has been shown experimentally to be weighted towards the proximal alveoli, more gas exchange occurs in the low molecular diffusivity mixture. Consideration of the various other mechanisms that have been proposed to explain the experimental findings.he inverse dependence suggests that they are of little significance. In particular, our studies remove the need to invoke Taylor diffusion to explain the experimental findings.

scholarly journals Quantifying seasonal air-sea gas exchange processes using noble gas time-series: A design experiment

2006 ◽  
Vol 64 (2) ◽  
pp. 267-295 ◽  
Author(s):  
Rachel H. R. Stanley ◽  
William J. Jenkins ◽  
Scott C. Doney
Keyword(s):  
Time Series ◽  
Gas Exchange ◽  
Noble Gas ◽  
Design Experiment ◽  
Exchange Processes

Understanding pulmonary gas exchange: ventilation-perfusion relationships

2004 ◽  
Vol 287 (6) ◽  
pp. L1071-L1072 ◽  
Author(s):  
John B. West
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Theoretical Study ◽  
Pulmonary Gas Exchange ◽  
Alveolar Air ◽  
Factors Affecting ◽  
Historical Significance ◽  
Partial Pressures ◽  
Classic Papers

This essay looks at the historical significance of four APS classic papers that are freely available online: Fenn WO, Rahn H, and OTIS AB. A theoretical study of the composition of the alveolar air at altitude. Am J Physiol 146: 637-653. 1946 ( http://ajplegacy.physiology.org/cgi/reprint/146/5/637 ). Rahn H. A concept of mean alveolar air and the ventilation-bloodflow relationships during pulmonary gas exchange. Am J Physiol 158: 21-30, 1949 ( http://ajplegacy.physiology.org/cgi/reprint/158/1/21) ). Riley RL. And Cournand A. "Ideal" Alveolar air and the analysis of ventilation-perfusion relationships in the lungs. J Appl Physiol 1: 825-847. 1949 ( http://jap.physiology.org/cgi/reprint/1/12/825) . Riley RL. And Cournand A. Analysis of factors affecting partial pressures of oxygen and carbon dioxide in gas and blood of lungs: theory. J Appl Physiol 4: 77-101. 1951 ( http://jap.physiology.org/cgi/reprint/4/2/77) .

ChemInform Abstract: The Role of Ate Complexes in Halogen(Metalloid)-Metal Exchange Reactions: A Theoretical Study.

ChemInform ◽  
2010 ◽  
Vol 29 (50) ◽  
pp. no-no
Author(s):  
G. BOCHE ◽  
M. SCHIMECZEK ◽  
J. CIOSLOWSKI ◽  
P. PISKORZ
Keyword(s):  
Theoretical Study ◽  
Metal Exchange ◽  
Exchange Reactions

A model theoretical study on ligand exchange reactions of CooA

2013 ◽  
Vol 15 (16) ◽  
pp. 6139 ◽  
Author(s):  
Toshimasa Ishida ◽  
Shigetoshi Aono
Keyword(s):  
Ligand Exchange ◽  
Theoretical Study ◽  
Exchange Reactions
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