The Equivalent Krogh Cylinder and Axial Oxygen Transport

1997 ◽  
pp. 191-202 ◽  
Author(s):  
Roy W. Schubert ◽  
Xuejun Zhang
Keyword(s):  
Oxygen Transport ◽  
Krogh Cylinder

Characterisation of production of organic rich topsoil from sludge

2000 ◽  
Vol 42 (9) ◽  
pp. 195-201 ◽  
Author(s):  
P. Andreasen ◽  
P. B. Mortensen ◽  
A. Stubsgaard ◽  
B. Langdahl
Keyword(s):  
Organic Matter ◽  
Oxygen Consumption ◽  
Oxygen Transport ◽  
Mineral Soil ◽  
Climatic Conditions ◽  
Growth Media ◽  
Soil Mixture ◽  
Water Suspension ◽  
Aerobic Process ◽  
Stable Product

The stabilisation of a sludge-mineral soil mixture and a method to evaluate the state of stabilisation were investigated. The organic matter and nitrogen content are reduced up to 50% during a stabilisation process of three months under Danish climatic conditions. The stabilisation was shown to be an aerobic process limited by oxygen transport within the mixture. The degree of stabilisation was evaluated by oxygen consumption in a water suspension and the results showed that a stable product was achieved when oxygen consumption was stable and in the level of natural occurring aerobic soils (0.1 mgO2/(g DS*hr). The study thereby demonstrates that a stability of a growth media can be controlled by the oxygen consumption method tested.

scholarly journals A Comparative Study of the Oxygen Transport Proteins of Dendrostomum pyroides

1972 ◽  
Vol 247 (18) ◽  
pp. 5959-5963
Author(s):  
Gerald L. Klippenstein ◽  
Dee A. Van Riper ◽  
Elizabeth A. Oosterom
Keyword(s):  
Comparative Study ◽  
Oxygen Transport ◽  
Transport Proteins

Forced Convection Past a Rotating Sphere: Modeling Oxygen Transport to a Pond Snail Embryo

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
D. A. Nield ◽  
A. V. Kuznetsov
Keyword(s):  
Forced Convection ◽  
Quantitative Study ◽  
Oxygen Transport ◽  
Oxygen Transfer ◽  
Pond Snail ◽  
Gaseous Exchange ◽  
Helisoma Trivolvis ◽  
Rotating Sphere

Helisoma trivolvis pond snail embryos are known for their rotation, which is induced by beating of cilia at the embryo's surface. A common hypothesis links this behavior to enhancing oxygen transfer to the embryo's surface. In this paper, this hypothesis is quantified, and the effect of the rotation on the supply of oxygen to an embryo, which is approximately spherical in shape, is studied. To the best of our knowledge, this is the first research presenting a quantitative study on the effect of an embryo's rotation on facilitating gaseous exchange between the embryo and the environment.

scholarly journals The Oxygen Transport Triad in High-Altitude Pulmonary Edema: A Perspective from the High Andes

2021 ◽  
Vol 18 (14) ◽  
pp. 7619
Author(s):  
Gustavo Zubieta-Calleja ◽  
Natalia Zubieta-DeUrioste
Keyword(s):  
Pulmonary Edema ◽  
High Altitude ◽  
Oxygen Transport ◽  
Acute Mountain Sickness ◽  
Breath Holding ◽  
Acid Base Balance ◽  
Initial Exposure ◽  
High Altitude Pulmonary Edema ◽  
Tolerance To Hypoxia ◽  
Dynamic Pump

Acute high-altitude illnesses are of great concern for physicians and people traveling to high altitude. Our recent article “Acute Mountain Sickness, High-Altitude Pulmonary Edema and High-Altitude Cerebral Edema, a View from the High Andes” was questioned by some sea-level high-altitude experts. As a result of this, we answer some observations and further explain our opinion on these diseases. High-Altitude Pulmonary Edema (HAPE) can be better understood through the Oxygen Transport Triad, which involves the pneumo-dynamic pump (ventilation), the hemo-dynamic pump (heart and circulation), and hemoglobin. The two pumps are the first physiologic response upon initial exposure to hypobaric hypoxia. Hemoglobin is the balancing energy-saving time-evolving equilibrating factor. The acid-base balance must be adequately interpreted using the high-altitude Van Slyke correction factors. Pulse-oximetry measurements during breath-holding at high altitude allow for the evaluation of high altitude diseases. The Tolerance to Hypoxia Formula shows that, paradoxically, the higher the altitude, the more tolerance to hypoxia. In order to survive, all organisms adapt physiologically and optimally to the high-altitude environment, and there cannot be any “loss of adaptation”. A favorable evolution in HAPE and pulmonary hypertension can result from the oxygen treatment along with other measures.

Effects of Sex and Physical Activity Level on Serum Biomarker-Based Physiological Dysregulation: The Impact to Predict Frailty and Mortality in the Quebec NuAge Cohort

Gerontology ◽  
2021 ◽  
pp. 1-14
Author(s):  
Ahmed Ghachem ◽  
Frédérik Dufour ◽  
Tamas Fülöp ◽  
Pierrette Gaudreau ◽  
Alan A. Cohen
Keyword(s):  
Physical Activity ◽  
Older Adults ◽  
Kidney Function ◽  
Oxygen Transport ◽  
Physical Activity Level ◽  
Rate Of Change ◽  
Activity Level ◽  
Men And Women ◽  
Physiological Dysregulation ◽  
The Impact

<b><i>Background:</i></b> Age-related changes in biological processes such as physiological dysregulation (the progressive loss of homeostatic capacity) vary considerably among older adults and may influence health profiles in late life. These differences could be related, at least in part, to the impact of intrinsic and extrinsic factors such as sex and physical activity level (PAL). <b><i>Objectives:</i></b> The objectives of this study were (1) to assess the magnitude and rate of changes in physiologi­cal dysregulation in men and women according to PAL and (2) to determine whether/how sex and PAL mediate the apparent influence of physiological dysregulation on health outcomes (frailty and mortality). <b><i>Methods:</i></b> We used data on 1,754 community-dwelling older adults (age = 74.4 ± 4.2 years; women = 52.4%) of the Quebec NuAge cohort study. Physiological dysregulation was calculated based on Mahalanobis distance of 31 biomarkers regrouped into 5 systems: oxygen transport, liver/kidney function, leukopoiesis, micronutrients, and lipids. <b><i>Results:</i></b> As expected, mean physiological dysregulation significantly increased with age while PAL decreased. For the same age and PAL, men showed higher levels of physiological dysregulation globally in 3 systems: oxygen transport, liver/kidney function, and leukopoiesis. Men also showed faster global physiological dysregulation in the liver/kidney and leukopoiesis systems. Overall, high PAL was associated with lower level and slower rate of change of physiological dysregulation. Finally, while mortality and frailty risk significantly increased with physiological dysregulation, there was no evidence for differences in these effects between sexes and PAL. <b><i>Conclusion:</i></b> Our results showed that both sex and PAL have a significant effect on physiological dysregulation levels and rates of change. Also, although a higher PAL was associated with lower level and slower rate of change of physiological dysregulation, there was no evidence that PAL attenuates the effect of physiological dysregulation on subsequent declines in health at the end of life. Substantial work remains to understand how modifiable behaviors impact the relationship between physiological dysregulation, frailty, and mortality in men and women.

Sign in / Sign up

Export Citation Format

Share Document