Properties of exact density functionals for electronic quantum transport

Density functional theory and its extension in the nonequilibrium regime, time-dependent density functional theory, are powerful tools for predicting the structures, energies and dynamics of electronic systems. Their usefulness derives from the Kohn-Sham scheme whereby a system of real, interacting particles is replaced by a fictitious system of non-interacting particles subject to an effective external potential instead of a pairwise particle-particle interaction. The Kohn-Sham universe yields the same observable phenomena as that predicted by standard quantum mechanics so long as the effective external potential is known. However, for the vast majority of systems it is not known, and the usually local (in time and space) functional approximations employed do not capture the physics of true nonlocal interactions. In this thesis, the exact charge and current densities of model quantum transport devices described by nonlocal potentials are studied and methods for reverse-engineering the corresponding exact Kohn-Sham effective external potential for time-dependent and steady-state density functional theory approaches to the same systems are presented, as well as the resulting exact potentials themselves. Features of improved functionals for calculating approximate Kohn-Sham systems are demonstrated. These functionals are suggested to be very different from existing functionals employed, describing not potentials but electric and magnetic fields, and have a strong dependence on the local and semilocal charge and current density

On some factors that effect the ‘feel’ of molecules

There is currently a trend towards the increasing use of nanotechnology in food. Emerging technology has the potential to modify the nutritional value and improve the quality of food products. Nevertheless there are difficulties. Perhaps the most problematic area is molecular sensing and in particular mechanical sensing as modification leads to structurally different molecules. The mucosal layers are the first point of contact in the mechanical sensory process. Mucins are the largest component of the mucosa and these high molecular weight glycoproteins can be found across all animal phyla. Their roles are diverse ranging from a non-specific immune response to lubricators. Mucin is investigated and it is proposed to adsorb in a concentration manner in a quasi-composite layer structure. This structure is related to its functional properties and is conserved over a wide temperature range.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

SmartBuildingAnalyser:A parametric early-stage analysis tool for multi-objective building design

This paper introduces SmartBuildingAnalyser (SBA), a set of components developed for Grasshopper to support rapid parametric design at early stages in the project lifecycle of building design. SBA is demonstrated on two projects to optimise a design for daylighting and for occupant productivity. Development of SBA is strongly governed by the needs of practising engineers and has been developed in such an environment where the challenges of industry workflows are acknowledged. These projects demonstrate some early usefulness of SBA in discovering Pareto optimal designs and visualising data sets, and the potential benefits of SBA are expected to grow with continued work on developing the user interface and in linking further analysis engines

Calcium Handling Defects and Cardiac Arrhythmia Syndromes

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Structural hysteresis and hierarchy in adsorbed glycoproteins

The adsorption and desorption of the giant heavily glycosylated protein mucin from solutions of different bulk concentrations have been followed at the nanometer scale using high resolution molecular microscopy based on optical waveguide lightmode spectroscopy. Modeling the layer as a uniaxial thin film allowed the in situ determination of adsorbed mass, mean layer thickness, and structural anisotropy. These parameters manifest highly significant adsorption-desorption hysteresis, indicating at least two dominant glycoprotein conformational types (i.e., molecular states, structurally and kinetically distinguishable). One of them is proposed to be a conformationally extended state that engenders uniaxial symmetry and dominates layers generated from low bulk concentrations. The revealed structure and the mechanism by which it is formed are postulated to be a general feature of the self-assembly of large glycoproteins. We expect that, inter alia, this knowledge will be relevant for understanding the extraordinary effectiveness of mucin thin films as boundary lubricants

Characterization and epitope mapping of human monoclonal antibodies to PDC-E2, the immunodominant autoantigen of primary biliary cirrhosis

Further to define the epitopes of PDC-E2, the major autoantigen in primary biliary cirrhosis (PBC), we have developed and characterized five human monoclonal antibodies. These antibodies were derived by fusing a regional hepatic lymph node from a patient with PBC with the mouse human heterohybrid cell line F3B6. Previous studies of epitope mapping of PDC-E2 have relied on whole sera and have suggested that the immunodominant epitope lies within the inner lipoyl domain of the molecule. However, selective absorption studies using whole sera and a series of overlapping recombinant peptides of PDC-E2 have suggested that the epitope may also include a large conformational component. Moreover, several laboratories have suggested that autoantibodies against the 2-oxo acids dehydrogenase autoantigens are cross-reactive. The five monoclonal antibodies generated included three IgG2a and two IgM antibodies and were studied for antigen specificity using recombinant PDC-E2, recombinant BCKD-E2, histone, dsDNA, IgG (Fc), collagen and a recombinant irrelevant liver specific control, the F alloantigen. The antibodies were also used to probe blots of human, bovine, mouse and rat mitochondria. Finally, fine specificity was studied by selective ELISA and absorption against overlapping expressing fragments of PDC-E2. All five monoclonals, but none of the other mitochondrial autoantigens were specific for PDC-E2. In fact, although affinity purified antibodies to PDC-E2 from patients with PBC cross-reacted with protein X, the human monoclonals did not, suggesting that protein X contains an epitope distinct from that found on PDC-E2. Additionally, all three IgG2 monoclonals recognized distinct epitopes within the inner lipoyl domain of PDC-E2. © 1992

Shaping electron wave functions in a carbon nanotube with a parallel magnetic field

A magnetic field, through its vector potential, usually causes measurable changes in the electron wave function only in the direction transverse to the field. Here we demonstrate experimentally and theoretically that in carbon nanotube quantum dots, combining cylindrical topology and bipartite hexagonal lattice, a magnetic field along the nanotube axis impacts also the longitudinal profile of the electronic states. With the high (up to 17T) magnetic fields in our experiment the wave functions can be tuned all the way from "half-wave resonator" shape, with nodes at both ends, to "quarter-wave resonator" shape, with an antinode at one end. This in turn causes a distinct dependence of the conductance on the magnetic field. Our results demonstrate a new strategy for the control of wave functions using magnetic fields in quantum systems with nontrivial lattice and topology.Comment: 5 figure