Tracers oxygen

Kainer R. A functional model of the rat kidney. J Math Biol 1979 7 57-94. Kassissia IG, Goresky CA, Rose CP, Schwab AJ, Simard A, Huet PM, Bach GG. Tracer oxygen distribution is barrier-limited in the cerebral microcirculation. Circ Res 1995 77 1201-11. 

The hydroxylation of acetanilide by liver microsomes has been studied with tracer oxygen (331). It has been found that the formation of p-hydroxyacetanilide involves incorporation of one atom of oxygen derived from molecular oxygen. Since TPNH is an essential component of the reaction, it is presumed that the other atom of the oxygen molecule is reduced to water. If this is the case, the liver hydroxylating system is a mixed function oxidase. 

In this review the enzymes that catalyze the reactions of molecular oxygen have been classified in three major groups the oxygen transferases, the mixed function oxidases, and the electron transfer oxidases. With the exception of lipoxidase, the oxygen transferases contain heavy metal which appears to be active in reduced form. In order to explain the experimental observations, particularly those involving tracer oxygen, the transfer of a molecule of oxygen to sub-... 

Since NRA focuses on inducing specific nuclear reactions, it permits selective observation of certain isotopes. This makes it ideal for tracer experiments using stable isotopes. Generally, there are no overlap or interference effects because reactions have very different Qvalues, and thus different resultant particle energies. This permits the observation of species present at relatively low concentrations. A good example is oxygen and O can be resolved unambiguously, as they are... 

Heavy isotopes endow the compounds in which they appear with slightly greater masses than their unlabeled counterparts. These compounds can be separated and quantitated by mass spectrometry (or density gradient centrifugation, if they are macromolecules). For example, O was used in separate experiments as a tracer of the fate of the oxygen atoms in water and carbon dioxide to determine whether the atmospheric oxygen produced in photosynthesis arose from HgO, COg, or both ... 

Determination of Barium and Strontium Peroxides (Active Oxygen) in Igniters In Small Arms Tracer Ammunition , FATR T-76059 (1975) 33) ChemRubHndbk (1975), B-71... 

Let s examine some of these redox reactions and look for their common characteristic. First, consider the reaction between magnesium and oxygen, which produces magnesium oxide (Fig. K.l) this reaction is used in fireworks to produce white sparks. It is also used, less agreeably, in tracer ammunition and incendiary devices. The reaction of magnesium and oxygen is a classic example of an... 

Isab, A.A., Shaw, C.E. Ill and Locke, J. (1988) GC-MS and oxygen-17 NMR tracer studies of triethylphosphine oxide formation from auranofin and water- O in the presence of bovine serum albumin an in vitro model for auranofin metabolism. Inorganic Chemistry, 27, 3406-3409. 

Due to their displayed higher photostability, indolenine-based cyanines and squaraines are preferred for the design of fluorescent tracers. Dicyanomethylene- and thio-squaraines with substituted squaraine oxygens also show potential as highly photostable fluorescent probes. 

Stable isotopes serve as naturally occurring tracers that can provide much information about how chemical reactions proceed in nature, such as which reactants are consumed and at what temperature reactions occur. The stable isotopes of several of the lighter elements are sufficiently abundant and fractionate strongly enough to be of special usefulness. Foremost in importance are hydrogen, carbon, oxygen, and sulfur. 

Jensen and Hvitved-Jacobsen (1991) developed a direct method for the determination of the air-water oxygen transfer coefficient in gravity sewers. This method is based on the use of krypton-85 for the air-water mass transfer and tritium for dispersion followed by a dual counting technique with a liquid scintillation counter (Tsivoglou et al 1965,1968 Tsivoglou andNeal, 1976). A constant ratio between the air-water mass transfer coefficients for dissolved oxygen and krypton-85 makes it possible to determine reaeration by a direct method. Sulfur hexafluoride, SF6, is another example of an inert substance that has been used as a tracer for reaeration measurements in sewers (Huisman et al., 1999). 

---