Tracer studies using

Tracer studies using 253Es show that einsteinium has chemical properties typical of a heavy trivalent, actinide element. 

Early studies on oxide films stripped from iron showed the presence of chromium after inhibition in chromate solutionand of crystals of ferric phosphate after inhibition in phosphate solutions. More recently, radio-tracer studies using labelled anions have provided more detailed information on the uptake of anions. These measurements of irreversible uptake have shown that some inhibitive anions, e.g. chromateand phosphate are taken up to a considerable extent on the oxide film. However, other equally effective inhibitive anions, e.g. benzoate" pertechnetate and azelate , are taken up to a comparatively small extent. Anions may be adsorbed on the oxide surface by interactions similar to those described above in connection with adsorption on oxide-free metal surfaces. On the oxide surface there is the additional possibility that the adsorbed anions may undergo a process of ion exchange whereby... 

More recently, Finlayson et al. (66) performed deuterium tracer studies using 2,2,4,4-tetramethylpentane as a model reactant, and proved that the bond-shift isomerization to 2,2,5-trimethylhexane may go via a monoad-sorbed intermediate on Pd (as well as on Pt, Ir, and Rh). The authors show that in the mechanisms of nondestructive reactions such as cyclization and bond-shift isomerization of alkanes, only one metal atom is required as the catalytic center. 

Kiene, R.P., and Linn, L. (2000) The fate dissolved dimethylsulfoniopropionate (DMSP) in seawater Tracer studies using 35S-DMSP. Geochim. Cosmochim. Acta 64, 2797-2810. 

Tracer studies using isotopically labeled CO have shown that four CO ligands in Mn(CO)5Br undergo exchange with 14CO, but the fifth (bonded trans to Br) does not ... 

The reduction of [Co(CN)5(02)]3 by Mov species in aqueous solution produces the bimetallomer (201), which is slowly decomposed in organic solvents to the 72-Mo(02) species (202).672 Tracer studies using, 802 show however that the peroxo bridge in (202) does not derive from [Co(CN)5(02)]3, 673... 

Numerous trace elements are known to be nutritionally essential in man In order to assess the essentiality, dietary availability, and metabolic fate of these, means of labeling for subsequent identification are needed In animal studies, radioisotopes are often used for this purpose, but their use in human studies is generally contraindicated due to the radiation hazards An alternate method is to use stable isotopes of the elements, which overcomes this limitation A method will be described for conveniently measuring the stable isotopes of selenium, permitting their use as metabolic tags in tracer studies Using one stable isotope as the tracer and another as internal standard, one can quantitatively identify in a sample the tracer, natural (unenriched) selenium present with it, and total selenium Some of the kinds of information obtainable from metabolic tracer studies will be discussed ... 

The initial planning of tracer studies using to measure nitrogen cycle rates requires... 

Both D-glucuronic acid and 2-amino-2-deoxy-D-glucose appear to be incorporated into the mucopolysaccharides through utilization of intact D-glucose, with prior or subsequent oxidation or amination, respectively. This has followed from tracer studies, using D-glucose-6-C" and D-glucose-... 

Tracer studies using 0 have established that the two main pathways to the chelated glycine complex (which is not the sole product) are (a) internal nucleophilic attack by bound hydroxide ion on the N-coordinated ester and (b) attack of external hydroxide on the chelated ester. 

Morimoto Y, Ukida M, Tsuji T. 1988. Dynamic relationship between urea and glutamine synthesis in the mechanism of ammonia detoxication a tracer study using 15NH4CL in fulminant hepatic failure rats. Gastroenterol Jpn 23(5) 538-545. 

Tracer studies using show that in these redox reactions H2( 0)2 is converted to ( 0)2, conhrming that no oxygen from the solvent (which is not labelled) is incorporated and the 0—0 bond is not broken. 

Although tracer studies using extracts of several plant species indicated that both L-serine and L-cysteine were substrates for the formation of j -cyano-L-alanine, the use of purified fractions (such as from Lupinus spp) revealed that cysteine was the authentic precursor serine was converted into this by the appropriate enzyme in the crude preparations. The cyanoalanine synthase from Lupinus was purified to homogeneity and its mechanism of action utilizing pyridoxal phosphate as a coenzyme was elucidatedj -Cyanoalanine hydrolyase which catalyses the hydration of 102- 103 has also been purified ... 

Biochemical investigations and tracer studies using the stable isotope... 

The concepts that are emerging with respect to the pathways of nitrogen and carbon assimilation in soybean roots and nodules are summarized in Figure 14. The scheme that is shown is based in part on the tracer studies using short-lived isotopes reported here along with published and unpublished observations. The figure is intended to present... 

Of course, there are more bulk properties of interest than the above parameters related to transport of the fast ions and electrons. Metal cation transport is minor, but still a most crucial parameter, because it eventually leads to membrane walkout, demixing, or decomposition in chemical gradients. Methods used for investigating metal cation diffusion comprise reactivity studies, interdiffusion couples, and tracer studies, using analytical SEM, EPMA, SIMS or radioactivity for the diffusion profile analyses. 

Tracer studies using C, N-doubly labeled cadaverine and NMR labeling experiments have shown that three units of cadaverine are incorporated into sparteine and two of the C—bonds from two of the cadaverine units remain intact [62, 63]. In accordance with the labeling patterns observed, two hypothetical models for the biosynthesis of the tetracyclic alkaloids have been formulated. 

Quantitative analysis of acetate groups in SRL and SRC samples were performed by a tracer study using l C-labeled acetic anhydride, proton nmr, carbon-13-nmr and saponification of acetate groups, followed by titration of liberated acetic acid. Comparison of results are reported in Table 3. 

The 5 2 allylic substitution of cinnamyl chloride by water in the presence of an (5)-Cp Ru catalyst and NaHC03 in aqueous THF at room temperature occurs with complete regiospeciflcity, giving a 93-99% yield of the branched allylic alcohol, with between 89 and 94% eeP A r-allyl-ruthenium complex is believed to form during the reaction. A tracer study using H2 0 showed that water is the nucleophile in the hydrolysis reaction. 

Morita-Baylis-Hillman carbonates undergo an hydrolysis in the presence of the asymmetric organocatalyst, hydroquinidine[anthraquinone-l,4-diyl] diether, and Cap2 in aqueous iV,iV-dimethylacetamide, yielding the allylic alcohol Tracer studies using showed that water is the nucleophile in the hydrolysis reaction. It is... 

Polymer formation of fullerene labeled with radionuclides was also observed. In a multi-tracer study using heavy-ion nuclear reaction of with Au formation of new metallofullerenes (Zr, Hf, and Mb included in fullerene) was also reported. 

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