The Na+-translocating NADH:quinone oxidoreductase (Na+-NQR) from Vibrio cholerae is a membrane-bound, respiratory Na+ pump. Its NqrF subunit contains one FAD and a [2Fe-2S] cluster and catalyzes the initial oxidation of NADH. A soluble variant of NqrF lacking its hydrophobic, N-terminal helix (NqrF') was produced in V. cholerae wild type and nqr deletion strain. Under identical conditions of gr...

We report pure zero field nuclear magnetic resonance (NQR) measurements on the optimally doped three layer highTc-compounds HgBaCaCuO and HgBaCaCuO(F) with Tc 1⁄4 134 K. Above Tc two Cu NQR line pairs are observed in the spectra corresponding to the two inequivalent Cu lattice sites. Below Tc the Cu NQR spectra show additional lines leading to the extreme broadened Cu NQR spectra at 4.2 K well ...

Context. Understanding the processes that could lead to an enrichment of molecules in 15N atoms is of particular interest because this may shed light on the relatively strong variations observed in the 14N/15N ratio in various solar system environments. Aims. The sample of molecular clouds where 14N/15N ratios have been measured currently is small and has to be enlarged to allow statistically s...

Trophic mass-balance models of ecosystems constructed using the Ecopath approach and software include the diet composition of functional groups as model inputs, and trophic level estimates for these same groups as a model outputs. The well-documented 0.34% enrichment of lSN/14N that occurs at each feeding step in food webs can be used to determine trophic level as well. This contribution is the...

Abstract Triple oxygen isotope (δ17O and δ18O) values of high- low-temperature altered oceanic crust products basalt alteration experiments were measured to better constrain ocean compositions in deep time. The data define an array δ18O Δ′17O (Δ′17O=δ′17O − λRL × δ′18O + γ) from mantle toward 1‰ −0.01‰, respectively, with a λ ~0.523. used construct model for estimating δ18O-Δ′17O the ancient oc...

Recent studies have reported slight but definite differences in Δ′17O between the lithosphere and hydrosphere. In present study, we precisely accurately quantify values of geothermal H2O mid-ocean ridge basalt (MORB) with normalization on VSMOW-SLAP scale to further substantiate these discuss isotopic evolution hydrosphere throughout geologic time scale. With a value -60 ± 13 × 10-6, MORB is co...

Some nitrogen-containing heterocycles can form both anionic (with abstraction of the N -H proton) and cationic derivatives (with addition of the proton to the pyridinic nitrogen atom). These include, in par­ ticular, 3,5-dichloro-l,2,4-triazole and 4,5-dichloro-2methylimidazole. These compounds were studied by 35C1 NQR spectroscopy [1,2]. Quantum-chemical analyses of the electronic structure of...

Identifying the sources and transformations of riverine nitrate plays a critical role in mitigating nitrogen enrichment river networks. Several previous studies have used δ18O-NO3− to quantitatively assess contributed by atmospheric terrestrial sources, but their results great uncertainty due wide range values isotopic fractionation during nitrogen-cycling processes environment. The 17O anomaly...

17O(p,p)17O elastic scattering cross sections were measured for the first time, on INSP SAFIR platform in Paris, using thin silica films prepared by thermal oxidation of Si under 17O2. The 17O content film was determined a combination ellipsometry and IBA measurements. yield elastically scattered protons from corresponding peak Elastic Backscattering spectra, with underlying signal reduced chan...

The method of random sampling was introduced for the first time in the nutation nuclear quadrupole resonance (NQR) spectroscopy where the nutation spectra show characteristic singularities in the form of shoulders. The analytic formulae for complex two-dimensional (2-D) nutation NQR spectra (I = 3/2) were obtained and the condition for resolving the spectral singularities for small values of an...