Pressure effects on Dirac fermions in α-(BEDT-TTF)?I?

We investigate the pressure effect on the layered Dirac fermion system, which is realized in quasi-two-dimensional organic compound α-(BEDT-TTF)?I?. The trajectory of the contact points is investigated using the tight-binding model with the transfer integrals determined by x-ray diffraction experiments. Vanishing of the Dirac fermion spectrum, opening of the gap, and pressure dependence of interlayer magnetoresistance are discussed.     

Electrical conduction of organic ultrathin films evaluated by an independently driven double-tip scanning tunneling microscope

The electrical transport properties of organic thin films within the micrometer scale have been evaluated by a laboratory-built independently driven double-tip scanning tunneling microscope, operating under ambient conditions. The two tips were used as point contact electrodes, and current in the range from 0.1 pA to 100 nA flowing between the two tips through the material can be detected. We demonstrated two-dimensional contour mapping of the electrical resistance on a poly(3-octylthiophene) thin films as shown below. The obtained contour map clearly provided an image of two-dimensional electrical conductance between two point electrodes on the poly(3-octylthiophene) thin film. The conductivity of the thin film was estimated to be (1-8) × 10(-6) S cm(-1). Future prospects and the desired development of multiprobe STMs are also discussed.     

Microglial responses around intrinsic CNS neurons are correlated with axonal regeneration

Background  

Microglia/macrophages and lymphocytes (T-cells) accumulate around motor and primary sensory neurons that are regenerating axons but there is little or no microglial activation or T-cell accumulation around axotomised intrinsic CNS neurons, which do not normally regenerate axons. We aimed to establish whether there was an inflammatory response around the perikarya of CNS neurons that were induced to regenerate axons through a peripheral nerve graft.     

Selective synthesis of organic sulfides and disulfides by the reduction of elemental sulfur with samarium diiodide

Elemental sulfur can be reduced to the corresponding thiolate anion species (S²⁻ and S²⁻₂) selectively by samarium diiodide in the presence and absence of HMPA, respectively. The subsequent alkylation of the thiolate anion species provides a useful synthetic route to dialkyl sulfides and disulfides. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9: 581–584, 1998