Thesis ( M.S. ) -- University of Texas at Arlington, 2008.

Thesis (doctoral)--Lunds Universitet, 1990.

Thesis (doctoral)--Lunds Universitet, 1990.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (p. 112-122).

The work contained in this thesis was concerned with rebreathing methods of measuring lung volume. In particular, one novel rebreathing technique which uses oxygen as the indicator gas was assessed. This technique appeared methodologically simple and readily applicable in a clinical environment. In essence, it relied on a graphical extrapolation of the time related changes in oxygen concentration to allow for oxygen uptake. This technique has been tested using a mass spectrometer which enabled nitrogen and argon as well as oxygen to be simultaneously used as indicator gases. Although the lung volumes as measured by the different indicator gases should have been the same, these were found to be different. These discrepancies were related to the concentration of the indicator gas which existed in the bag and lung prior to rebreathing. A hypothesis explaining these inconsistancies was formulated. This was based on an initial but non-sustained output of carbon dioxide into the bag-plus-lung system. A numerical model of idealised rebreathing showed that the hypothesis was sufficient to explain the discrepancies observed. A correction procedure was devised which performed successfully in the model. This correction was incorporated into an on-line computing procedure for calculating real lung volume. When tested in normal subjects this gave consistent results for lung volume, irrespective of indicator gas employed. The corrected lung volumes were unaffected by the initial gas compositions in the bag and lung, and were also independent of non-sustained gas exchange, whether this was due to carbon dioxide and/or nitrous oxide. This technique could, therefore, be use under anaesthetic conditions, since the uptake or output of nitrous oxide no longer upsets the calculation of lung volume. The use of more than one indicator gas, within the same manoeuvre, was shown to provide a valuable indication of the presence of errors in the system. When this approach was applied to more conventional rebreathing techniques of lung volume measurement, it also highlighted the presence of inaccuracies.

Thesis (M. Sc.)--University of Adelaide, Dept. of Physiology, 1989. / Typescript (Photocopy). Includes bibliographical references (leaves 42-52).

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 26, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Peter Pfeifer. Vita. Includes bibliographical references.

Thesis (M.S.)--Springfield College, 2002. / Includes bibliographical references.

The purpose of this investigation was to examine the change in pulmonary ventilation (V_E), ventilatory equivalent of oxygen (VE_O_2) and lactic acid (LA) in relation to oxygen uptake (V_O_2) as predictors of the lactate threshold (LT). Eight healthy male (21.9 ± 3.0 years) subjects conducted three incremental-load tests. In each test the initial work rate consisted of 4 minutes of unloaded pedaling ("0" load) followed by incremental-load work of 360 Kgm • min^-1 at 60 rpm for trial I and trial II, while during trial III the work rate consisted of 540 Kgm • min^-1 of incremental-load work at 90 rpm. Work load was increased every third minute until the subject reached voluntary exhaustion. Blood samples from a forearm vein were collected during trial II (60 rpm) and trial III (90 rpm) and analyzed for lactic acid. In our subjects the measured (x̄ ± SD) lowest VE_O_2 for O_2 in relation to V_O_2 for trial I of 22.9 ± 1.9 occurred at a V_O_2 of 1.27 ± 0.8 L • min^-1. For trial II the VE_O_2 of 22.4 ± 1.3 occurred at a V_O_2 of 1.30 ± 0.09 L • min^-1, while for trial III a VE_O_2 of 24.4 ± 2.5 occurred at a V_O_2 of 1.84 ± 0.15 L • min^-1. The lowest VE_O_2 and onset of LA accumulation as calculated from individual exponential equations relating V_E to V_O_2 yielded V_O_2 values at 1.77 ± 0.18 L • min^-1 and 1.74 ± 0.25 L • min^-1 for trial II, and 1.83 ± 0.19 L • min^-1 and 2.02 ± 0.53 during trial III. Utilizing ln[LA]-ln V_O_2 equations, the LT occurred at a V_O_2 of 1.30 ± 0.07 L • min^-1 during trial II and 1.85 ± 0.12 L • min^-1 during trial III. It was concluded that during the 60 rpm test that the lactate threshold was best predicted by measured lowest VE_O_2 and the plot of the In[LA] to In V_O_2 relationship. The methods used in this study provide a valid and reliable estimate of the lactate threshold and support the use of measured lowest VE_O_2 , a respiratory gas exchange measure, as an indirect measure of the lactate threshold.

Ozone is recognized as one of the most dangerous irritants to eyes, throat, lungs and etc .. Chamber studies consistently have demonstrated adverse effects of ozone on human lung function. The results of epidemiological studies, however, have been controversial, partly because there are many factors that affect human lung function. Thus it has been difficult to control confounding in epidemiological studies. Among these factors, retention and ventilation are two of the more important because of their strong influence on ozone's physiologically effective dose. This study used a computer simulation model, utilizing data from the "children's Camp Study", to analyze the effects of retention factors and ventilation on ozone's physiologically effective dose. The results of the simulations indicated appreciable improvement in the estimated exposure to ozone when inhaled ozone exposure (effective dose) was included in the model. These results were consistent with the study's a priori- hypothesis (that incorporating retention and ventilation factors into the model would improve the estimated exposure to ozone) primarily because of the greater precision and reduction in bias associated with the use of heart rate data that were child-and hour-specific. The study identified three simulation data sets for which the ozone dose model yielded a more significant coefficient than did the average ozone concentration model. Using the t-statistic, the three models were seen to follow the expected pattern, with statistically significant differences between the R² values (the coefficient of variation changed from 45.4 to 11.0 when the error term was 0. 01). The results of the analyses support the hypothesis that ventilation and retention factors can be used to increase the precision of ozone exposure measurement and reduce exposure assessment errors significantly, thereby sharpening the power of studies evaluating ozone's acute health effects. / Graduation date: 1992