Due to its high carrier mobility, graphene is considered a suitable material for use in field-effect transistors. However, its application to immunosensing of small molecules is still elusive. To investigate the potential of graphene field effect transistors (G-FET) as a sensor for small molecules with small or no charge, we applied the open-sandwich immunoassay (OS-IA), which detects low-molecular-weight antigens noncompetitively, to G-FET. Using an antibody variable fragment V L immobilized on graphene and a hyperacidic region of amyloid precursor protein fused to the other variable fragment V H , we successfully detected a small antigen peptide consisting of 7 amino acids (BGP-C7), with a more than 100-fold increase in sensitivity compared with that measured by enzyme-linked OS-IA. Furthermore, we succeeded in detecting BGP-C7 in the presence of human serum with similar sensitivity, suggesting its potential application in clinical diagnostics.

A modified Nordheim-Gorter relation is established in this paper which involves a characteristic thermopower of the deviation from Matthiessen's rule and the deviation itself. The relation shows why the characteristic thermopower of the solute, obtained at high temperatures via the normal Nordheim-Gorter rule is generally erroneous as also are previous estimates of the phonon drag thermopower in dilute alloys. A two band model is invoked in considering the validity of the modified Nordheim-Gorter rule and it is established that when any anisotropy of electron-phonon scattering is temperature dependent, the diffusion thermopower of pure metals is nonlinear in temperature. It is also shown that the apparent phonon drag enhancement observed in AI alloys may be explained in terms of diffusion thermoelectricity.

As-grown superconducting BiSrCaCuO thin films were grown at 650°C on MgO(100) substrates by RF magnetron sputtering from three targets. The substrate was rotated over the three targets: Bi3Sr2Ca2Cu3O x , Bi2Sr3Ca3Cu3O x and Bi2Sr2Ca2Cu4.5O x . By adjusting the staying time of the substrate over each target, it was possible to precisely control the chemical composition of the thin film. This paper describes the superconducting properties, surface morphology and crystal structures of sputtered films formed by varying the staying time. X-ray diffraction measurement showed that the crystal structure could be changed by varying the staying time. The film with the optimum composition showed zero resistivity at 75 K and had an exceedingly smooth surface. This film had the mixed phase which is considered to be a stacked structure consisting of a high-T c phase and a low-T c phase.

In situ epitaxial growth of BiSrCaCuO films by three target sputtering was performed on MgO substrates at a temperature of 650°C. From high resolution transmission electron microscopy, the film showed a superstructure consisting of the alternate stacking of the low-T c and high-T c phases with a c-axis of 34 Å. The film in the [110] or [1 1̄0] directions was parallel to <100 >MgO, and the transient layers between the substrate and the film were less than a few atomic layers thick. X-ray diffraction simulations indicated that the films contained random layer ordering of 34 Å bi-layers (low-T c+high-T c and high-T c+low-T c) and random layer ordering of low-T c and high-T c phase layers.