Adsorption differences between low coverage enantiomers of alanine on the chiral Cu{421}R surface.

Chiral separation using heterogeneous methods has long been sought after. Chiral metal surfaces have the potential to make it possible to model these systems using small amino acids, the building blocks for proteins. A comparison of submonolayer concentrations of alanine enantiomers adsorbed onto Cu{421}R has revealed a large geometrical differences between the two molecules as compared to the saturated coverage. Large differences were observed in HR-XPS and NEXAFS and complemented by theoretical DFT calculations. At approximately one third of a monolayer a comparison of the C1s XPS signal showed a shift in the methyl group of more than 300 meV indicating that the two enantiomers are in different chemical environments. NEXAFS spectroscopy confirmed the XPS variations and showed large differences in the orientation of the adsorbed molecules. Our DFT results show that the l-enantiomer is energetically the most stable in the {311} microfacet configuration. In contrast to the full monolayer coverage, these lower coverages showed enhanced selectivity.

Multipolar and dark-mode plasmon resonances on drilled silver nano-triangles.

Dark-mode plasmon resonances can be excited by positioning a suitable nano-antenna above a nanostructure to couple a planar incident wave-front into a virtual point source. We explore this phenomenon using a prototypical nanostructure consisting of a silver nanotriangle into which a hole has been drilled and a rod-like nano-antenna of variable aspect ratio. Using numerical simulations, we establish the behavior of the basic drilled nanotriangle under plane wave illumination and electron beam irradiation to provide a baseline, and then add the nano-antenna to investigate the stimulation of additional dark-mode plasmon resonances. The introduction of a suitably tuned nano-antenna provides a new and general means of exciting dark-mode resonances using plane wave light. The resulting system exhibits a very rich variety of radiant and sub-radiant resonance modes.

Personality factors and drug of choice in female addicts with psychiatric comorbidity.

Female addicts (N= 108) with a mean age of 37.2 were tested using the Temperament and Character Inventory (TCI) in 1996-97. In a representative sub-sample (N = 49) assessed with the Structured Clinical Interview. DSMIIIr (SCID), 82% manifested an axis-1-syndrome (lifetime), and 53% a personality disorder. Of the 108 addicts, 42 preferred alcohol, 14 heroin, 33 amphetamines, and 19 benzodiazepines. Maturity was low, but there were no differences in maturity between drug preference groups. Results indicated that those less mature were more "novelty-seeking" and "harm-avoidant", while those maturer tended to be more persistent. Less mature persons answered less consistently. They agreed more with different items and their answers were more rare when compared to the general population. Heroin addicts were less sentimental and helpful and more aware of their own resources. Benzodiazepine and amphetamine addicts were more self-transcendent and self-forgetful. Among the relatively more mature, benzodiazepine addicts scored higher than heroin and alcohol addicts on "true" and rare answers. In conclusion, maturity and the drug of choice among female addicts were related to different TCI scales.