نتایج جستجو برای: 2h isotope shift
تعداد نتایج: 178729 فیلتر نتایج به سال:
Cell cultures of Catharanthus roseus were supplied with [2-13C, 3-2H]-deoxyxylulose or [2-13C,4-2H]1-deoxyxylulose. Lutein and chlorophylls were isolated from the cell mass, and hydrolysis of the chlorophyll mixtures afforded phytol. Isotope labeling patterns of phytol and lutein were determined by 2H NMR and 1H,2H-decoupled 13C NMR. From the data it must be concluded that the deuterium atom in...
The isotope shifts of forbidden transitions in Beand B-like argon ions are calculated. It is shown that only using the relativistic recoil operator can provide a proper evaluation of the mass isotope shift, which strongly dominates over the field isotope shift for the ions under consideration. Comparing the isotope shifts calculated with the current experimental uncertainties indicates very goo...
Surface and groundwater resources such as Arnaveh karstic spring and Shirin Dareh reservoir are the main sources of drinking water and agricultural activity in the North Khorasan province, northeast of Iran. The main agents of this study are to evaluate the origin, hydrochemical and isotope characteristics of water resources and also suitability of the Shirin dareh reservoir water for drinking ...
The flavoprotein 2-aminobenzoyl-CoA monooxygenase/reductase from the eubacterium Azoarcus evansii catalyzes the dearomatization of 2-aminobenzoyl-CoA. The reaction consists in an O2-dependent monooxygenation at the benzene position 5, which is followed immediately by an NADH-dependent hydrogenation of the intermediate at the same catalytic locus. The reaction was studied by 1H, 2H, and 13C NMR ...
Groundwater contamination due to municipal solid waste landfills leachate is a serious environmental threat. During recent years, the use of stable isotopes as tracers identify groundwater phenomena has found application engineering. Deuterium (2H) and oxygen (18O) have successfully used if submitted interactions with leachate, significant organic amount. The paper shows two case studies, in ce...
In a condensation between [3-3H3]pyruvate and D-glyceraldehyde-3-P as catalyzed by 2-keto-3-deoxygluconate-6-P aldolase (EC 4.1.2.14) of Pseudomonas putida, C--C synthesis occurred appreciably faster than C--3H bond breaking. Since tritium is present in tritiated pyruvate in tracer amounts, this result showed hydrogen isotope discrimination in pyruvate deprotonation and suggests enolpyruvate ge...
Monitoring of stable water isotopes (18O and 2H) in precipitation and surface waters in the Mackenzie River basin of northern Canada has created new opportunities for researchers to study the complex hydrology and hydroclimatology of this remote region. A number of prior studies have used stable isotope data to investigate aspects of the hydrological regime of the wetland-dominated terrain near...
The data that students collect from the typical advanced undergraduate experiment on saturated absorption spectroscopy (SAS) of rubidium can be used to measure isotope shift and thus lead an estimate isotopic ground-state energy shift. This helps refine their “picture” atomic ground state. We describe theoretically why SAS works well with free-running laser diodes, demonstrate this fact experim...
Interferometrically-measured wavelengths of 109 lines of neutral Kr84 are compared with those of Kr86. Sixty energy levels of neutral Kr84 derived from those wavelengths and 25 Kr86-Kr84 isotope shifts previously measured are given along with their shifts from the energy levels of Kr86. Twenty levels of each of Kr82, Kr80, and Kr78 are also evaluated using isotope-shift information in the liter...
Abstract. There is growing interest in developing spatially resolved methane (CH4) isotopic source signatures to aid geographic attribution of CH4 emissions. hydrogen isotope measurements (?2H–CH4) have the potential be a powerful tool for differentiation emissions from freshwater environments, as well other microbial sources. This because ?2H–CH4 values are partially dependent on ?2H environme...
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