Superoxide reductase (SOR) is an Fe protein that catalyzes the reduction of superoxide to give H(2)O(2). Recently, the mutation of the Glu47 residue into alanine (E47A) in the active site of SOR from Desulfoarculus baarsii has allowed the stabilization of an iron-peroxo species when quickly reacted with H(2)O(2) [Mathé et al. (2002) J. Am. Chem. Soc. 124, 4966-4967]. To further investigate this...

On the basis of the isomer-specific effects of trans fatty acids (FA) on human health, and the detrimental effect of t10,c12-conjugated linoleic acid (CLA) on cows' milk fat production, there is a need to identify factors that affect the shift from trans-11 to trans-10 pathway during ruminal biohydrogenation of FA. This experiment was conducted in vitro and aimed at separating the effects of th...

An approach is presented for the structure determination of clathrates using NMR spectroscopy of enclathrated xenon to select from a set of predicted crystal structures. Crystal structure prediction methods have been used to generate an ensemble of putative structures of o- and m-fluorophenol, whose previously unknown clathrate structures have been studied by 129 Xe NMR spectroscopy. The high s...

The isomer shift calibration constants have been calculated for 57.60 keV in 127I and for 27.72 keV in 129I resonant transitions by density functional theory. The full-potential linearized augmented plane-wave method (FLAPW) was applied in the scalar-relativistic approach. The NaI compound was used to set the origin of the scales in both cases. On the basis of the existing experimental data, th...

We report experimental studies to understand the reaction mechanism of the intermetallic anode Cu2Sb with Na and demonstrate that it is capable of retaining about 250 mAh g−1 over 200 cycles when using fluoroethylene carbonate additive. X-ray diffraction data indicate during the first discharge the reaction leads to the formation of crystalline Na3Sb via an intermediate amorphous phase. Upon de...

One metastable linkage nitrosyl isomer can be generated in [Pt(NH(3))(4)Cl(NO)]Cl(2) by irradiation with light in the red spectral range. The potential energy barrier for the thermal relaxation of the metastable state to the ground state has an amount of E(A) = (0.27 +/- 0.03) eV. The decay follows the Arrhenius law and E(A) is independent of temperature. At room temperature the metastable stat...

Charge-transfer excitations highly depend on the electronic coupling between the donor and acceptor groups. Nitrophenolates are simple examples of charge-transfer systems where the degree of coupling differs between ortho, meta and para isomers. Here we report the absorption spectra of the isolated anions in vacuo to avoid the complications of solvent effects. Gas-phase action spectroscopy was ...

A detailed ir and nmr study has confirmed the absolute configurational assignments of diastereomeric {3hydroxy (-acetoxy) episulfides. The concentration dependence of the bonded and free hydroxyl absorptions of the alcohols shows that the isomer previollsly assigned the 25,3R, or threo configuration (I, R = H) forms the stronger intramolecular hydrogen bond (~v = 138 cmI ), whereas the isomer a...