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The chiral induced spin selectivity effect is an excited states phenomenon, which can be probed using photo‐spectroscopy as well as transport measurements. On the one hand such measurements represent averaged quantities, on the other hand nearly all theoretical descriptions, with only a few exceptions, have been concerned with energy dependent properties of the pertinent structures. While those properties may or may not be relevant for the chiral induced spin selectivity effect, many of those properties have been attributed as being the, or part of the, origins of the effect. Here, it is demonstrated that, for instance, the spin‐resolved transmission provides little, if any, information about the chiral induced spin selectivity effect. Moreover, although effective single‐electron theory can be used in this context, reasons are given for why such descriptions are not viable. [ABSTRACT FROM AUTHOR]

The focus of this review is recent work in which we have demonstrated a highly-flexible approach to the study of Fano-resonance phenomena, by making use of the mesoscopic devices known as quantum point contacts (QPCs). Utilizing the ability of these structures to function as an 'on-demand quantum state', we demonstrate a highly-flexible system for the investigation of Fano resonances. Our approach involves making measurements of non-locally coupled pairs of QPCs, one of which is used to form the discrete state needed for the Fano resonance, while the other serves as a detector whose conductance is sensitive to the energy of this state. As a demonstration of the flexibility of this approach, we show how it can be used to implement a 'multi-state' Fano resonance, in which two discrete states undergo a robust interaction that is achieved by coupling them to each other through a common continuum. [ABSTRACT FROM AUTHOR]

The formulation of the time-dependent tunnel current in quantum dot (QD) systems in the (generalized) transfer Hamiltonian formalism is reconsidered, taking into account the nonorthogonality between the subsystems. Exploiting the fact that only the total charge in the system is conserved, in general, gives rise to a new formulation of the transport theory. As a result, it is shown necessary to depart from the orthodox picture, in which the current is treated as a local property of the system. A general formula for the current is derived. By expressing properties of the quantum dot in the Hubbard I approximation with the loop correction, thereby including strong correlations of the QD states, numerical results are given for various time-dependent source-drain voltages. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003 [ABSTRACT FROM AUTHOR]

Cutaneous lupus erythematosus (LE) often presents clinically as chronic cutaneous lesions, healing with scar formation, and acute cutaneous lesions that are seen in systemic and subacute LE and heal without scarring. UV-light plays a role in the pathogenesis of the skin lesions, but the pathomechanism is still unclear. The aim of this study was to compare fibroblast proliferation and response to UV-light by cultured fibroblasts from scarring and non-scarring LE lesions. Fibroblasts were cultured from skin lesions from 5 patients with classic discoid LE, 5 patients with subacute cutaneous LE and healthy, age-matched donors. Proliferation rate was assessed by cell counts at days 3, 6 and 9. The fibroblast cultures were irradiated with UVA and the supernatants were analysed for IL-6, TGF-β, IL-4, soluble ICAM-1 and soluble VCAM-1. Fibroblast cultures from scarring lesions showed significantly lower cell-counts at days 3 (P=0.01) and 9 (P=0.009), than cultures from non-scarring lesions or controls. There were no significant differences in levels of IL-6 or TGF-β in supernatants of irradiated fibroblasts from patients compared to controls and IL-4 and the soluble forms of ICAM-1 and VCAM-1 were below detection level. The response to UV-irradiation was similar to that of normal cells in the parameters studied. In summary, cultured fibroblasts from scarring LE lesions displayed significantly decreased proliferation rates compared to non-scarring LE lesions and controls. This may be secondary to inflammatory factors, or due to a functional defect in LE fibroblasts. [ABSTRACT FROM AUTHOR]

Psoriasis is a hyperproliferative inflammatory disease and 70% of patients develop a chronic plaque form. The pathogenesis of psoriasis is not known but evidence exists that T cells play a crucial role. The T cell V-gene receptor repertoire from psoriasis skin (different layers) was compared with peripheral blood T cells by employing RNA polymerase chain reaction (PCR) amplification. T cell receptor (TCR) BV 5.1, 11, 12, 13.1 and 16 were utilized to a significantly higher degree in areas close to the basal layers when compared to CD4+, CD8+ or unfractionated blood T cells from the same patients, whereas only BV 11 and 13.1 genes of T cells from deeper layers of the dermis showed such a skewed usage. No biased usage of TCRBV genes was observed in superficial layers or in whole skin. Furthermore, T cell receptor junctional diversity analysed by high resolution gel electrophoresis showed skin psoriatic T cells to be poly- or oligoclonal. In conclusion, we show that TCRBV gene usage from different layers of psoriatic skin has a different pattern compared with the corresponding gene usage in circulating peripheral blood T cells. This pattern may implicate possible skin-associated antigen or superantigens activating a limited number of T cells in areas of skin close to basal layers, which in turn could promote keratinocyte proliferation. [ABSTRACT FROM AUTHOR]