Effect of Oxygen Deprivation and Reoxygenation on Endothelin-Induced Contractions of Porcine Coronary Artery1

2015 ◽  
pp. 221-231
Author(s):  
David J. Schmidt ◽  
Denise Koth ◽  
Denise Jubenville ◽  
Robert F. Highsmith
Keyword(s):  
Oxygen Deprivation ◽  
Effect Of Oxygen

Effect of oxygen deprivation on soil hydrophobicity during heating

2005 ◽  
Vol 14 (4) ◽  
pp. 449 ◽  
Author(s):  
R. Bryant ◽  
S. H. Doerr ◽  
M. Helbig
Keyword(s):  
Heat Source ◽  
Forest Soils ◽  
Water Droplet ◽  
Oxygen Deprivation ◽  
Eucalypt Forest ◽  
Soil Hydrophobicity ◽  
Effect Of Oxygen ◽  
Penetration Time ◽  
Droplet Penetration ◽  
Heating Duration

Previous studies of the effects of heating on soil hydrophobicity have been conducted under free availability of oxygen. Under fire, however, soils may be deprived of oxygen due to its consumption at the heat source and inadequate replenishment in the soil. In the present study, effects of heating on soil hydrophobicity are examined for three initially hydrophobic Australian eucalypt forest soils under standard and oxygen-deprived atmospheres for temperatures (T) of 250–600°C and durations (tE) 2–180 min. Hydrophobicity assessments using water droplet penetration time (WDPT) tests indicate substantial differences between the absence and presence of oxygen. Heating to 250–300°C enhanced hydrophobicity from initial respective WDPTs of 2029 s, 361 s and 15 s to > 18 000 s for all samples under both atmospheres. Depending on heating duration, hydrophobicity was eliminated (WDPTs ~0 s) in air between 210 and 340°C, but under oxygen-deprived conditions between 400 and 510°C. Relationships between the destruction temperature for hydrophobicity TD and tE provide temperature–duration thresholds below which hydrophobicity persists under oxygen concentrations <21%. As established temperature–duration thresholds for hydrophobicity destruction are based on the free availability of oxygen, caution is advised in their applicability to field situations where heating under burning may occur in oxygen-depleted conditions.

EFFECT OF OXYGEN DEPRIVATION ON CORNEAL SENSITIVITY

2009 ◽  
Vol 58 (3) ◽  
pp. 434-439 ◽  
Author(s):  
MICHEL MILLODOT ◽  
DANIEL J. O'LEARY
Keyword(s):  
Oxygen Deprivation ◽  
Corneal Sensitivity ◽  
Effect Of Oxygen

scholarly journals Changes to coral health and metabolic activity under oxygen deprivation

2016 ◽  
Author(s):  
James WA Murphy ◽  
Robert H Richmond
Keyword(s):  
Critical Role ◽  
Metabolic Stress ◽  
Oxygen Deprivation ◽  
Tissue Loss ◽  
Low Oxygen ◽  
Invasive Algae ◽  
Hypoxic Conditions ◽  
Coral Stress ◽  
Coral Health ◽  
Effect Of Oxygen

Scleractinian corals play a critical role in tropical marine ecosystems by providing essential structure and food for coral reef inhabitants. However, recent investigations have found an alarming increase in coral losses from a variety of stressors, which threatens the general health and resilience of tropical coastal ecosystems. The effect of oxygen deprivation on the health of Hawaiian corals based on local drivers is of particular concern. On Hawaiian reefs, the fast-growing, invasive algae Gracilaria salicornia overgrows coral heads, restricting water flow and light, thereby smothering corals. Field data shows hypoxic conditions (dissolved oxygen (DO2) < 2 mg/L) occurring underneath algal mats at night, and concurrent bleaching and partial tissue loss of shaded corals. This study evaluates changes in coral health and metabolism through the replication of hypoxic conditions in a laboratory setting in order to limit the contribution of additional environmental variables to health shifts. Analyses of metabolic stress were accomplished through the quantification of lactate dehydrogenase and opine dehydrogenase activities. Through experimentation, treatment corals were observed to exhibit significant increases in alanopine and strombine dehydrogenase activities (ADH and SDH, respectively), but little to no lactate or octopine dehydrogenase activity. These findings indicate that not only is hypoxia a major source of increased coral stress, which occurs in response to invasive algae mat smothering, but provide novel insight into coral metabolic shifts in extremely low-oxygen environments and point to ADH and SDH as possible tools for hypoxia mitigation.

Effect of oxygen deprivation on treatment processes in a full-scale drinking water biofilter

2015 ◽  
Vol 15 (4) ◽  
pp. 825-833 ◽  
Author(s):  
D. A. Søborg ◽  
I. L. Breda ◽  
L. Ramsay
Keyword(s):  
Drinking Water ◽  
Oxygen Deprivation ◽  
Full Scale ◽  
Water Levels ◽  
Raw Water ◽  
Filter Media ◽  
Deprivation Period ◽  
Treatment Processes ◽  
Effect Of Oxygen ◽  
Iron Manganese

Dissolved oxygen is critical for proper operation of waterworks that utilize anaerobic groundwater and rely on biofilters to remove iron, manganese and ammonium. In these biofilters, planned or inadvertent oxygen deprivation may occur for a variety of reasons. The water quality effects of oxygen deprivation on the function of drinking water biofilters, however, have not previously been reported. In this study, a 5-day oxygen deprivation period in full-scale biofilters was found to affect iron, manganese and ammonium concentrations differently. During the oxygen deprivation period, iron continued to be removed, although a greater depth of filter media was required to carry out the removal. Manganese oxide in filter media was mobilized, causing manganese water concentrations to increase well above raw water levels. The ammonium in the raw water passed through the biofilters unchanged, indicating the dependence of nitrification microorganisms on oxygen as their sole electron acceptor. Stringent national drinking water criteria were exceeded during the deprivation period but were once again met within hours after oxygenation was recommenced. Manganese and nitrite recovery to pre-deprivation concentrations, however, required days. The results illustrate the interdependence of treatment parameters and provide valuable practical information to waterworks that experience or plan oxygen stoppage.

scholarly journals Changes to coral health and metabolic activity under oxygen deprivation

2016 ◽  
Author(s):  
James WA Murphy ◽  
Robert H Richmond
Keyword(s):  
Critical Role ◽  
Metabolic Stress ◽  
Oxygen Deprivation ◽  
Tissue Loss ◽  
Low Oxygen ◽  
Invasive Algae ◽  
Hypoxic Conditions ◽  
Coral Stress ◽  
Coral Health ◽  
Effect Of Oxygen

Scleractinian corals play a critical role in tropical marine ecosystems by providing essential structure and food for coral reef inhabitants. However, recent investigations have found an alarming increase in coral losses from a variety of stressors, which threatens the general health and resilience of tropical coastal ecosystems. The effect of oxygen deprivation on the health of Hawaiian corals based on local drivers is of particular concern. On Hawaiian reefs, the fast-growing, invasive algae Gracilaria salicornia overgrows coral heads, restricting water flow and light, thereby smothering corals. Field data shows hypoxic conditions (dissolved oxygen (DO2) < 2 mg/L) occurring underneath algal mats at night, and concurrent bleaching and partial tissue loss of shaded corals. This study evaluates changes in coral health and metabolism through the replication of hypoxic conditions in a laboratory setting in order to limit the contribution of additional environmental variables to health shifts. Analyses of metabolic stress were accomplished through the quantification of lactate dehydrogenase and opine dehydrogenase activities. Through experimentation, treatment corals were observed to exhibit significant increases in alanopine and strombine dehydrogenase activities (ADH and SDH, respectively), but little to no lactate or octopine dehydrogenase activity. These findings indicate that not only is hypoxia a major source of increased coral stress, which occurs in response to invasive algae mat smothering, but provide novel insight into coral metabolic shifts in extremely low-oxygen environments and point to ADH and SDH as possible tools for hypoxia mitigation.

The Effect of Oxygen Deprivation on Inorganic Nitrogen Uptake in an Antarctic Macrolichen

1996 ◽  
Vol 28 (4) ◽  
pp. 347-354 ◽  
Author(s):  
P. D. Crittenden
Keyword(s):  
Nitrogen Uptake ◽  
Initial Rate ◽  
Inorganic Nitrogen ◽  
Oxygen Deprivation ◽  
Rate Of Decline ◽  
Effect Of Oxygen

AbstractSnow meltwater containing 36 ng ml−1 NO3−−N (raised here to between 95–101 ng ml−1 NO3−−N) and 112 ng ml−1 NH4+ −N was sprayed onto illuminated Usnea sphacelata at 2°C in a 2−1 capacity transparent perspex chamber force-ventilated with either air or O2− (and CO2−) free N2. The NO3-concentration in meltwater recirculated through a layer of U. sphacelata fell to c. 8 ng ml−1 after 1.25 h. Although the pattern of decline was broadly comparable in both air and N2, the initial rate of decline was lower in N2. When undepleted meltwater was continuously sprayed onto the lichen and the effluent collected for analysis, the lichen was found to retain 55% of the wet deposited NO3− in air but only 27% under N2. Up to 90%) of NH4+ supplied in a continuous spray of meltwater was retained by the lichen but this was affected little by O2 and CO2 deprivation.

scholarly journals The Effect of Oxygen Deprivation on the Cell Cycle of Drosophila melanogaster Embryos

1999 ◽  
Vol 45 (4, Part 2 of 2) ◽  
pp. 53A-53A
Author(s):  
Benjamin H Huffard ◽  
Robert M Douglas ◽  
Gabriel G Haddad
Keyword(s):  
Cell Cycle ◽  
Drosophila Melanogaster ◽  
Oxygen Deprivation ◽  
Effect Of Oxygen
Sign in / Sign up

Export Citation Format

Share Document