Boson-conserving one-nucleon transfer operator in the interacting boson model

The boson-conserving one-nucleon transfer operator in the interacting boson model (IBA) is reanalyzed. Extra terms are added to the usual form used for that operator. These new terms change generalized seniority by one unit, as the ones considered up to now. The results obtained using the new form for the transfer operator are compared with those obtained with the traditional form in a simple case involving the pseudo-spin Bose-Fermi symmetry $U^{B}(6) \otimes U^F(12)$ in its $U^{BF}(5) \otimes U^F(2)$ limit. Sizeable differences are found. These results are of relevance in the study of transfer reactions to check nuclear supersymmetry and in the description of (\beta)-decay within IBA.Comment: 13 pages, 1 table, 0 figures. To be published in Phys. Rev.

Simulation of complex plasmonic circuits including bends

Using a finite-element, full-wave modeling approach, we present a flexible method of analyzing and simulating dielectric and plasmonic waveguide structures as well as their mode coupling. This method is applied to an integrated plasmonic circuit where a straight dielectric waveguide couples through a straight hybrid long-range plasmon waveguide to a uniformly bent hybrid one. The hybrid waveguide comprises a thin metal core embedded in a two–dimensional dielectric waveguide. The performance of such plasmonic circuits in terms of insertion losses is discussed

Simulations of hybrid long-range plasmon modes with application to 90 degrees bends

We perform rigorous simulations of hybrid long-range modes guided by a central metal core and a two-dimensional dielectric slab. We show that these modes are subject to fewer limitations than conventional long-range plasmon modes in terms of field confinement and guiding performance. These hybrid modes may offer substantial improvements for integrated plasmonic components, as illustrated here by the consideration of 90° bends

Direct Observation of Transitions between Surface-Dominated and Bulk Diffusion Regimes in Nanochannels

The diffusion of charged proteins in liquid-filled nanometer-sized apertures with charged surfaces has been investigated with fluorescence correlation spectroscopy (FCS). Based on a two-dimensional (2D) multicomponent diffusion model, key parameters such as the number of molecules diffusing freely inside the nanochannel or interacting with the surfaces, together with the specific diffusion parameters, could be extracted. Different regimes of diffusion have been observed and described by a model, which takes into account the steric exclusion, the reversible surface adsorption of the biomolecules, and the exclusion-enrichment effect that is due to the charge of the proteins and the ionic strength of the solution. Conditions where the diffusion of proteins through nano-confined spaces can be of the same magnitude as in the bulk were both predicted and experimentally verified

Correlation effects in single-particle overlap functions and one-nucleon removal reactions

Single-particle overlap functions and spectroscopic factors are calculated on the basis of the one-body density matrices (ODM) obtained for the nucleus $^{16}O$ employing different approaches to account for the effects of correlations. The calculations use the relationship between the overlap functions related to bound states of the (A-1)-particle system and the ODM for the ground state of the A-particle system. The resulting bound-state overlap functions are compared and tested in the description of the experimental data from (p,d) reactions for which the shape of the overlap function is important.Comment: 11 pages, 4 figures include

One Body Density Matrix, Natural Orbits and Quasi Hole States in 16O and 40Ca

The one body density matrix, momentum distribution, natural orbits and quasi hole states of 16O and 40Ca are analyzed in the framework of the correlated basis function theory using state dependent correlations with central and tensor components. Fermi hypernetted chain integral equations and single operator chain approximation are employed to sum cluster diagrams at all orders. The optimal trial wave function is determined by means of the variational principle and the realistic Argonne v8' two-nucleon and Urbana IX three-nucleon interactions. The correlated momentum distributions are in good agreement with the available variational Monte Carlo results and show the well known enhancement at large momentum values with respect to the independent particle model. Diagonalization of the density matrix provides the natural orbits and their occupation numbers. Correlations deplete the occupation number of the first natural orbitals by more than 10%. The first following ones result instead occupied by a few percent. Jastrow correlations lower the spectroscopic factors of the valence states by a few percent (~1-3%) and an additional ~8-12% depletion is provided by tensor correlations. It is confirmed that short range correlations do not explain the spectroscopic factors extracted from (e,e'p) experiments. 2h-1p perturbative corrections in the correlated basis are expected to provide most of the remaining strength, as in nuclear matter.Comment: 25 pages, 9 figures. Submitted to Phys.Rev.

Fluorescent Labeling of SNAP-Tagged Proteins in Cells

One of the most prominent self-labeling tags is SNAP-tag. It is an in vitro evolution product of the human DNA repair protein O6 -alkylguanine-DNA alkyltransferase (hAGT) that reacts specifically with benzylguanine (BG) and benzylchloropyrimidine (CP) derivatives, leading to covalent labeling of SNAP-tag with a synthetic probe (Gronemeyer et al., Protein Eng Des Sel 19:309–316, 2006; Curr Opin Biotechnol 16:453–458, 2005; Keppler et al., Nat Biotechnol 21:86–89, 2003; Proc Natl Acad Sci U S A 101:9955– 9959, 2004). SNAP-tag is well suited for the analysis and quantification of fused target protein using fluorescence microscopy techniques. It provides a simple, robust, and versatile approach to the imaging of fusion proteins under a wide range of experimental conditions. © Springer Science+Business Media New York 2015