The oxygen dependence of cholesterol side chain cleavage to form pregnenolone was measured, using both purified phospholipid vesicle-reconstituted cytochrome P-450scc and rat adrenal mitochondria. At saturating cholesterol and nonlimiting electron supply (via NADPH-adrenodoxin reductase and adrenodoxin) the Km(O2) is low (4 microM). Limitations in the availability of both cholesterol and reduct...

the accurate estimation of reaeration rate coefficient, because of its effects on dissolved oxygen in rivers, is one of the most important initial steps of water quality management. the main goal of this paper is to evaluate the effects of reaeration rate coefficient on the river water dissolved oxygen, case study dinachal river, iran. to achieve these aims, water quality samples were collected...

The Wave Bioreactor is widely used in cell culture due to the benefits of disposable technology and ease of use. A novel cellbag was developed featuring a frit sparger to increase the system's oxygen transfer. The purpose of this work was to evaluate the sparged cellbag for yeast cultivation. Oxygen mass transfer studies were conducted in simulated culture medium and the sparged system's maximu...

It should now be beyond doubt that blastocyst culture results in better pregnancy rate (PR). This calls for fewer embryos to be transferred, and indeed blastocyst culture is of most value when the intention is to put back one embryo at a time. The PR with one top-grade blastocyst is 45-65% in different studies. If two top-grade blastocysts are transferred, the PR usually does not differ, but th...

A series of molybdenum(vi) cis-dioxo complexes containing tetradentate salan ligands with different para-substitutions on the phenoxy group have been prepared. These complexes catalyse the oxygen atom transfer reaction between dimethylsulfoxide and triphenylphosphine. During oxo transfer catalysis, the complexes are resistant to formation of catalytically inactive oxo-bridged dimeric Mo(v) comp...

Short-term oxygen consumption and filtration rate experiments were conducted to evaluate the response of edible cockle Cerastoderma edule when infested by the Digenean trematod Labratrema minimus. In this experiment the metabolic activities of bivalves were measured to detennine this particular aspect of the host-parasite interaction. We have used the Bucephalidae digenea Labratrema minimus inf...

Thermodynamic electron-transfer potentials from biology textbooks elucidate the sequence of electron-transfer events in the respiratory chain in mitochondria. In this study, thermodynamic and kinetic oxygen-transfer potentials have been defined and predicted for oxidants and substrates using density functional theory, aiming to rationalize multiple oxygen-transfer events in chemical catalysis, ...

OBJECTIVE Oxygen enhanced pulmonary MRI is a promising modality for functional lung studies and has been applied to a wide range of pulmonary conditions. The purpose of this study was to characterize the oxygen enhancement effect in the lungs of healthy, never-smokers, in light of a previously established relationship between oxygen enhancement and diffusing capacity of carbon monoxide in the l...

Oxygen transfer in the capillary fringe (CF) is of primary importance for a wide variety of biogeochemical processes occurring in shallow groundwater systems. In case of a fluctuating groundwater table two distinct mechanisms of oxygen transfer within the capillary zone can be identified: vertical predominantly diffusive mass flux of oxygen, and mass transfer between entrapped gas and groundwat...