Theory of Edge Effects and Conductance for Applications in Graphene-Based Nanoantennas

In this paper, we present a theory of edge effects in graphene for its applications to nanoantennas in the THz, infrared, and visible frequency ranges. The novelty of the presented model is reflected in its self-consistency, which is reached due to the formulation in terms of dynamical conductance instead of ordinary surface conductivity. The physical model of edge effects is based on using the concept of the Dirac fermion and the Kubo approach. In contrast with earlier well-known and widely used models, the surface conductance becomes non-homogeneous and non-local. The numerical simulations of the spatial behavior of the surface conductance were performed in a wide range of values, known from the literature, for the graphene ribbon widths and electrochemical potential. It is shown that if the length exceeds 800 nm, our model agrees with the classical Drude conductivity model with a relatively high degree of accuracy. For rather short lengths, the conductance exhibits a new type of spatial oscillations, which are not present in the ordinary conductivity model. These oscillations modify the form of effective boundary conditions and integral equations for electromagnetic field at the surface of graphene-based antenna. The developed theory opens a new way for realizing electrically controlled nanoantennas by changing the electrochemical potential via gate voltage. The obtained results may be applicable for the design of different carbon-based nanodevices in modern quantum technologies

The clinical presentation of autoimmune thyroid disease in men is associated with IL12B genotype

Background Common variants in the interleukin 12B (IL12B) gene are associated with predominantly inflammatory (Th1) or antibody-mediated (Th2) immune responses. As Hashimoto’s disease and Graves’ disease are thought to arise from mainly Th1 and Th2 immune responses respectively, we hypothesized that IL12B genotype may influence the clinical presentation of autoimmune thyroid disease. Objective We tested for differences in IL12B genotype between Graves’ disease and Hashimoto’s disease. Patients We studied a discovery cohort of 203 Australian women and 37 men with autoimmune thyroid disease, a replication cohort of 100 European men and a cohort of 146 Chinese men. Intervention We analysed three IL12B variants: rs41292470, in the promoter; rs3212227, in the 3¢ untranslated region and rs6887695, located 60 kilobases upstream from the coding region. Results In the discovery cohort, rs41292470 and rs3212227 genotypes did not differ significantly between Hashimoto’s disease and Graves’ disease. In Australian men (but not women), rs6887695 genotype differed between Hashimoto’s disease and Graves’ disease, with a minor allele frequency (MAF) of 14% and 41%, respectively (P = 0Æ034). This result was confirmed in the European men (MAF 24% and 41%; P = 0Æ013). On combined analysis of Australian, European and Chinese men (N = 285), the difference was highly significant (MAF 23% and 45%; P = 3 · 10)5). In 233 men without thyroid disease, the MAF was 34%, significantly different from Graves’ disease (P = 0Æ005) and Hashimoto’s disease (P = 0Æ029). Conclusion In men with autoimmune thyroid disease, a common variant located upstream of the IL12B coding region may influence whet