Nuclear quadrupole resonance (NQR) combines the spatial localization capability and convenience of metal detection or ground-penetrating radar (GPR) with the compound specific detection capability offered by chemical detection techniques. Starting in the mid-1990s, groups at Quantum Magnetics Inc. and the Naval Research Laboratory made considerable improvements in the basic scientific and instr...

Monte Carlo method was used to study the characteristics of neutron interactions with cells underneath a water medium layer with varying thickness. The following results were obtained. (1) The fractions of neutron interaction with 1H, 12C, 14N and 16O nuclei in the cell layer were studied. The fraction with 1H increased with increasing medium thickness, while decreased for 12C, 14N and 16O nucl...

The binding of Mg2+ with adenine nucleotides is an important problem in enzyme-catalyzed phosphoryl transfer reactions. The previously used 31P chemical shift method has been shown to be inadequate to define the chelation pattern of the Mg2+ complex with adenosine 5'-triphosphate (ATP) [Jaffe, E. K., & Cohn, M. (1978) Biochemistry 17, 652-657]. The center of controversy is whether the alpha-pho...

The Na+ translocating NADH:quinone oxidoreductase (Na+-NQR) is a unique respiratory enzyme catalyzing the electron transfer from NADH to quinone coupled with the translocation of sodium ions across the membrane. Typically, Vibrio spp., including Vibrio cholerae, have this enzyme but lack the proton-pumping NADH:ubiquinone oxidoreductase (Complex I). Thus, Na+-NQR should significantly contribute...

17O-NMR spectroscopy was employed as an innovative method to help understand mechanistic pathways in sugar fragmentation. Elucidation of reaction mechanisms to final Maillard end products was achieved by starting from specific intermediates obtained by synthesis, such as 1-deoxy-D-erythro-hexo-2,3-diulose. This alpha-dicarbonyl was thermally treated in the presence of 17O-enriched water under a...

We report 121 Sb nuclear quadrupole resonance (NQR) measurements on kagome superconductor CsV 3 5 with T c = 2.5 K. NQR spectra split after a charge density wave (CDW) transition at 94 K, which demonstrates commensurate CDW state. The coexistence of the high temperature phase and between 91 K manifests that it is first order transition. exhibits tri-hexagonal deformation lateral shift adjacent ...

A series of oxonium and carboxonium ions and their corresponding protonated dications were investigated by ab initio/IGLO/GIAO-MP2 methods. The calculated 17O and 13C NMR chemical shifts were compared with the solution phase experimental data for the monocations. The structures and energies of a number of oxonium and carboxonium dications and the effect of diprotonation on the 17O and 13C NMR c...

[(S)-16O,17O]Thiophosphoenolpyruvate has been used as a substrate in H218O for the reaction catalyzed by phosphoenolpyruvate carboxylase, and the absolute configuration of the product, inorganic [16O,17O,18O]thiophosphate, has been determined. The reaction proceeds with inversion of configuration at phosphorus, thus ruling out the cyclic mechanism that has been proposed for this enzyme. The ste...

Na(+) is the second major coupling ion at membranes after protons, and many pathogenic bacteria use the sodium-motive force to their advantage. A prominent example is Vibrio cholerae, which relies on the Na(+)-pumping NADH:quinone oxidoreductase (Na(+)-NQR) as the first complex in its respiratory chain. The Na(+)-NQR is a multisubunit, membrane-embedded NADH dehydrogenase that oxidizes NADH and...

The zero field 14N-hfs-multiplets and the high-field Zeeman-hfs-multiplets of low-J rotational transitions of the title compounds were observed in a flash pyrolysis setup under high-resolution conditions. From the zero-field hfs patterns the 14N spin-rotation coupling constants and the 14N nuclear quadrupole coupling constants were obtained. From the high-field Zeeman-hfs-multiplets, the diagon...