The lines of the Mg I spectrum, lying in the visible and in the photographic infrared regions, have been examined and some of them found to show structure. It is pointed out that the structure should be attributed to isotope shift, which, in the case of the 3s3p 'P —3s3d 'D series, owes its origin to the fact-that the smd 'D terms, perturbed by the p''D term, have passed on to this term some of...

In multi-elemental compound-specific isotope analysis the lambda (?) value expresses shift of one element versus a second element. dual-isotope plots, slope regression lines typical reveals footprint underlying effects allowing to distinguish degradation pathways an organic contaminant molecule in environment. While different conventions and fitting procedures are used literature determine ?, i...

Isotopic composition of snow cover and streamflow was determined in a snowdominated, forested watershed to quantify the spatial variability and processes that alter stable isotope (oxygen-18, 18O and deuterium, 2H) composition under different forest canopy conditions (clear-cut, partial-cut (thinned), and unimpacted forest). Snow sampling was carried out on 4 days in late winter and early sprin...

The reaction of two D-amino acid oxidases from the yeasts Rhodotorula gracilis and Trigonopsis variabilis with the substrates alanine and valine in their 2-1H and 2-2H forms was studied employing the stopped-flow spectrophotometric technique. The turnover numbers at infinite substrate and oxygen concentrations were: 20,700/4,250 and 1,730/360 ([2-1H]/[2-2H]alanine and valine, respectively) for ...

An atomic spectral line is characteristic of the element producing the spectrum. The line also depends on the isotope. The program ris3 (Relativistic Isotope Shift) calculates the electron density at the origin and the normal and specific mass shift parameters. Combining these electronic quantities with available nuclear data, isotope-dependent energy level shifts are determined.

[3,5-2H]Salicylate was obtained by a hydrogen/deuterium exchange reaction carried out in 2H2O. Using this deuterated salicylate as a substrate for salicylate hydroxylase, the product catechol was isolated and characterized with respect to the positions of deuterium retention. Based on nuclear magnetic resonance and mass spectroscopy analyses, the product was identified as [3,5-2H]catechol. It i...

alpha-1,3-Fucosyltransferase V (FucT V) catalyzes the transfer of 1-fucose from the donor sugar guanosine 5'-diphospho-beta-1-fucose (GDP-Fuc) to an acceptor sugar. A secondary isotope effect on the fucosyltransfer reaction with guanosine 5'-diphospho-[1-2H]-beta-1-fucose (GDP-[1-2H]-Fuc) as the substrate was observed and determined to be Dv = 1.32 +/- 0.13 and DV/K = 1.27 +/- 0.07. Competitive...

Abstract: Isotope labelling is a powerful tool to study elemental cycling within terrestrial ecosystems. Here we describe a new multi-isotope technique to label organic matter (OM). We exposed poplars (Populus deltoides x nigra) for 14 days to an atmosphere enriched in 13CO� and depleted in 2H�1�O. After one week, the water-soluble leaf OM (�13C = 1346 ± 162‰) and the leaf water were strongly l...