DFT models of molecular species in carbonate molten salts.

Raman spectra of high temperature carbonate melts are correlated with carbonate species modeled at 923 K using B3LYP/(6-311+G(2d,p)) density functional calculations. Species that are theoretically stable at 923 K include O(2-), O(2)(-), O(2)(2-), CO(3)(2-), C(2)O(6)(2-), CO(4)(-), CO(4)(2-), CO(4)(4-), CO(5)(2-), KCO(4)(-), LiCO(4)(-), KO(2)(-), LiO(2)(-), NaO(2)(-), KO(2), LiO(2), NaO(2), KCO(3)(-), LiCO(3)(-), and NaCO(3)(-). Triangular, linear, and bent forms are theoretically possible for KO(2)(-) and NaO(2)(-).

Aggregation models of potential cyclical trimethylsulfonium dicyanamide ionic liquid clusters.

Raman and infrared spectra of trimethylsulfonium dicyanamide [(CH(3))(3)SN(CN)(2)] are reported and accurately reproduced by DFT methods (B3LYP and B3PW91), MP2, and MP3, and to a lesser extent by the RHF method. The (CH(3))(3)SN(CN)(2) ionic liquid forms two isomeric dimers that are of cyclic structure, one of which is 13 kcal/mol lower in energy than the other. Both isomeric cyclic pairs (versions 1 and 2), [(CH(3))(3)SN(CN)(2)](2), have the potential to further combine and form a common structure containing four pairs of (CH(3))(3)SN(CN)(2).

13C NMR relaxation rates in the ionic liquid 1-ethyl-3-methylimidazolium butanesulfonate.

A new method of obtaining molecular reorientational dynamics from 13C spin-lattice relaxation data of aromatic carbons in viscous solutions is applied to 13C relaxation data of both the cation and anion in the ionic liquid, 1-ethyl-3-methylimidazolium butanesulfonate ([EMIM]BSO3). 13C pseudorotational correlation times are used to calculate corrected maximum NOE factors from a combined isotropic dipolar and nuclear Overhauser effect (NOE) equation. These corrected maximum NOE factors are then used to determine the dipolar relaxation rate part of the total relaxation rate for each aromatic 13C nucleus in the imidazolium ring.

A Bloembergen-Purcell-Pound 13C NMR relaxation study of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate.

The molecular structure and rotational motion of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) were studied over a wide temperature range using the Bloembergen-Purcell-Pound 13C NMR spin-lattice relaxation method and NOE factors. Examination of the spin-lattice relaxation times (T1) and the rates (R1 = 1/T1) of the 1-butyl-3-methylimidazolium cation reveals the relative motions of each carbon in the imidazolium cation. The rotational characteristics of the [BMIM] cation are supported by ab-initio molecular structures of [BMIM][PF6] using density functional theory (DFT) and Hartree-Fock (HF) methods.

Evidence for spin diffusion in a H,H-NOESY study of imidazolium tetrafluoroborate ionic liquids.

The ionic liquids 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) and 1-methyl-3-propylimidazolium tetrafluoroborate ([PMIM][BF4]) were studied by H,H-NOESY NMR using a cross-relaxation matrix analysis. Cross-peak intensities are seen to increase with increasing mixing time. Experimental and theoretical hydrogen-hydrogen distances are in agreement at short mixing times (50 ms).

Molecular reorientational dynamics of the neat ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate by measurement of 13C nuclear magnetic relaxation data.

The reorientational dynamics of the ionic liquid 1-butyl-3-methylimidzolium hexafluorophosphate ([BMIM]PF6) were studied over a wide range of temperatures by measurement of 13C spin-lattice relaxation rates and NOE factors. The reorientational dynamics were evaluated by performing fits to the experimental relaxation data. Thus, the overall reorientational motion was described by a Cole-Davidson spectral density with a Vogel-Fulcher-Tammann temperature dependence of the correlation times.

Examination of cadmium(II) complexation by the Suwannee River fulvic acid using 113Cd NMR relaxation measurements.

Aquatic and terrestrial fulvic acids are environmentally important because they affect the bioavailability and transport of metal ions. Prior studies demonstrated that Cd(ll) binds to the oxygen containing functional groups of fulvic acids. The complexation of Cd(II) is further investigated in this study using 113Cd NMR relaxation measurements for solutions of the Suwannee River fulvic acid (SRFA).

Measurement of cadmium(II) and calcium(II) complexation by fulvic acids using 113Cd NMR.

Aquatic and terrestrial fulvic acids are environmentally important in pollution transport because they affect the bioavailability and transport of metal ions. The complexation of the metal ions, Cd(II) and Ca(II), with several fulvic acids is examined in this study using 113Cd NMR. Our results indicate that Cd(II) predominately binds to the oxygen containing functional groups of the fulvic acids.

Affinity chromatography of glucose dehydrogenase.

Porcine liver beta-D-glucose dehydrogenase, a multi-functional protein, has been purified to apparent homogeneity. The enzyme has been separated from the endoplasmic reticulum using Triton X-114 and further purified using NAD to release glucose dehydrogenase from a NADP-linked sepharose column. The purified enzyme is capable of producing both NADH and NADPH in vivo as indicated by kinetic studies.

Inhibitory effect of disulfiram (Antabuse) on alcohol dehydrogenase activity.

We investigated the effect of disulfiram (Antabuse) on the activity of alcohol dehydrogenase (EC 1.1.1.

Characterization studies of glucose dehydrogenase.

Porcine liver beta-D-glucose dehydrogenase has been isolated using Triton X-114 to release it from the endoplasmic reticulum. The purified enzyme contains a limited amount (1.7%) of lipid material, including cholesterol, fatty acids, mono and diglycerides, phosphatidylcholine, phosphatidylethanolamine, and cholesterol esters.

Guanidinium- and temperature-induced conformational changes in glucose dehydrogenase.

The conformational changes in glucose dehydrogenase are studied as a function of temperature and guanidinium chloride (GdmCl) concentration. The data were analyzed assuming a two-conformer model which gave similar results using either circular dichroism or enzyme activity. The free energy of denaturation was 0.

Strategic power relationships in contemporary profit and nonprofit hospitals.

A comparative analysis of the intraorganizational power distributions of strategic decision makers in profit and nonprofit institutions was conducted to assess the effect of the institution's economic orientation. Hypotheses are tested, and the usefulness of an organization's economic orientation as a major strategic contingency variable is discussed.

6-Phosphogluconate dehydrogenase. Purification and kinetics.

A method is described for the isolation and purification of 6-phosphogluconate dehydrogenase from pig liver. The molecular weight is estimated at 83,000 and that of the subunits is 42,000 as determined by gel electrophoresis. The pH maximum is 8.

A kinetic study of glucose-6-phosphate dehydrogenase.

The steady state kinetics of pig liver glucose-6-phosphate dehydrogenase is consistent with an ordered, sequential mechanism in which NADP is bound first and NADPH released last. Kia is 9.0 muM, Ka is 4.

Glucose-6-phosphate dehydrogenase. Purification and partial characterization.

Glucose-6-phosphate dehydrogenase has been purified 1000-fold from pig liver. This enzyme exists as an active dimer of molecular weight 133,000 and an inactive monomer of molecular weight 67,500. The pH of maximum activity is 8.