Self-interaction correction and isotropic hyperfine parameter of light atoms

Numerical self-consistent field (SCF) calculations in density functional theory (DFT) and the local spin-density approximation (LSDA) were performed for the light atoms H, Li, B, C, N, O and F, in order to investigate the effect of the self-interaction correction (SIC) on the isotropic (or contact) hyperfine parameter A_ISO. In contrast to the findings for certain 3d-metals and compounds, results for light-atom SI-corrected A_ISO present no improvement over the LSDA values. We show that relatively modest changes to the correlation potential can lead to significant improvement of densities near the nucleus and the related A_ISO, suggesting a direction for future improvements in DFT functionals.     

Postmortem activation analysis: Preliminary observations in the preterm infant

Few data exist on the elemental composition of the human body during infancy. The scarcity of the data is due, in part, to the destructive nature of total body analyses normally required for the classical chemical approach. To help determine such data for infants, we have developed a neutron activation facility for nondestructive postmortem analyses. The system consists of a multisource²⁴¹AmBe irradiator and a multidetector NaI(T1) whole body counter. The total body contents of K, Ca, P, Na and Cl are determined. Postmortem examinations have been performed in twelve infant cadavers. These results are compared with those of the reference fetus.     

Monoclonal antibody purification ofTrichoderma reesei EG I

Applied Biochemistry and Biotechnology -     

Transformations between monomeric,dimeric, and trimeric phosphazanes: oligomerizing NP analogues of olefins

Isolation and characterization of a crystal mixture of iminophosphine 1 and diphosphazane 2 (R = Mes*, X = OTf) is enabled by the steric interactions between bulky substituents implicating monomer/dimer 1/2 equilibria and the conclusion is supported by the observation of a ring-expansion reaction to give a triphosphazane 3 (R = Dipp, X = Cl).     

Mass spectra of some 2-, 3-, and 4-pyridinecarboxylic acids. Further evidence of a N-H interaction for loss of carbon dioxide

Mass spectra of 3-acetamido-, 3-methoxy-, and 4-methoxy-2-pyridinecarboxylic acids, 2,6-pyridinedicarboxylic acid, 4-nitro-2-pyridinecarboxylic acid N-oxide, 2-chloro- and 2-nitro-x-pyridinecarboxylic acids (X = 3 and 5), 2-chloro- and 2-nitro-4-pyridinecarboxylic acids, and 4-pyridinecarboxylic acid are reported. The 2-pyridinecarboxylic acids lost carbon dioxide (M-44) as has been reported. The 3-pyridinecarboxylic acids showed no definite trend in fragmentation; however, the 4-pyridinecarboxylic acids lost OH (M-17) first. This change in fragmentation pat-tern is due to an interaction of the ring nitrogen and carboxyl group in the 2-pyridinecarboxylic acids which is not present in the 4-pyridinecarboxylic acids.     

Preparation and molecular structure of a pyrazolyl-ruthenium complex, Ru{C3H2NN(SO2tol)}(dppe)Cp*

The reaction between RuCl(dppe)Cp* and Me₃SiCCC(SiMe₃)NNHTs has given the pyrazole derivative (1), which was characterised by a single-crystal X-ray structure determination. Complex 1 is probably formed by attack of the NTs group on the π-complexed desilylated alkyne, with concomitant loss of a proton.     

Templateless room-temperature assembly of nanowire networks from nanoparticles

We demonstrate a new, room-temperature approach to assemble two-dimensional and three-dimensional networks of gold nanowires by agitating nanoparticles in a toluene-aqueous mixture, without the use of templates. The nanowires have a uniform diameter of about 5 nm and consist of coalesced face-centered cubic nanocrystals. Toluene molecules passivate the gold surfaces during nanoparticle coalescence, rendering the nanowires hydrophobic and enabling their transfer into the toluene layer. Such templateless low-temperature assembly of mesostructures from nanoscale building blocks open up new possibilities for creating porous self-supporting nanocatalysts, nanowires for device interconnection, and low-density high-strength nanofillers for composites.     

Polymer adsorption on platinum: Surface coverage determination using iodide-125

Adsorption of iodide-125, a γ emitter, was used as a quantitative methodology for polymer adsorption surface coverage analysis. Adsorption of I-125 on clean platinum produced surface elemental ratios of I:Pt of 1:4. The technique was applied to the adsorption of polyethylene glycol terephthalate from trifluoroacetic acid on platinum flags with a 2-cm² surface area. This polymer adsorption is approximated by a logarithmic relationship similar to the Temkin isotherm. Polymer coverage attained up to 99.6% of the surface.