Piezoresistivity of conducting polyaniline/BaTiO<SUB>3</SUB> composites

Conducting polyaniline/barium titanate (PANI/BaTiO<SUB>3</SUB>) composites exhibiting piezoresistivity properties have been synthesized by the in situ deposition technique by placing a fine grade powder of BaTiO<SUB>3</SUB> in the polymerization reaction mixture. The polyaniline was formed preferentially on the ceramic particles giving a much higher yield for PANI than in absence of the BaTiO<SUB>3</SUB> These composites exhibited piezoresistivity with the piezosensitivity being maximum at a certain composition. The current-voltage characteristics clearly revealed a nonlinear space charge controlled charge transport process. A large hysteresis in these characteristics was also observed which was dependent on the BaTiO<SUB>3</SUB> content in a composite. The various results have been explained on the basis of the charge transport mechanism in the heterogeneous conducting material having insulating domains dispersed in it

Clear Cell Variant of Mucoepidermoid Carcinoma-Maxillary Region: A Case Report

The clear cell variant of mucoepidermoid carcinoma (MEC) has been described in the major and minor salivary glands, oral cavity, skin and the bronchus. We report a case of clear cell variant of MEC of maxillary region in a 60 year old male who presented with a huge, disfiguring, lobulated maxillary mass. To our knowledge, this variant has not been previously reported in the maxillary region

Preparation and characterisation of silver quantum dot superlattice using self-assembled monolayers of pentanedithiol

A superlattice of silver nanoclusters was prepared using sequential self-assembly of 1,5-pentanedithiol on an Au(111) substrate. The formation of highly ordered silver nanocluster arrays was confirmed using AFM and also by the longitudinal periodicity observed in the low angle X-ray diffraction pattern. In contrast to the behaviour of dithiol self-assembled monolayers (SAM) on gold substrates, which give only blocking behaviour, the superlattice exhibits interesting electrochemical properties in terms of redox accessibility of silver nanoclusters with respect to potential cycling. The room temperature emission spectrum suggests the formation of minibands in the superlattice structure as evidenced by three distinct peaks at 320, 400 and 620 nm

Preparation, characterization and mechanistic features of zirconia films on bare and functionalized gold surfaces

Electrochemical synthesis of microcrystalline ZrO<SUB>2</SUB> at room temperature on bare and functionalized gold surfaces is reported to illustrate the biomimetic conditions of nucleation and growth. ZrO<SUB>2</SUB> films prepared on self-assembled monolayers (SAMs) of pentane-1,5-dithiol (PDT) on polycrystalline gold surfaces reveal a high degree of orientation and a distinct cleavage face, in contrast to monoclinic films, obtained on bare gold surfaces at room temperature. Cyclic voltammetry (CV), X-ray photoelectron spectroscopy (XPS), impedance measurement, current-transients, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to follow the monolayer formation, Zr-attachment on the SAM-modified surface and subsequent difference in nucleation conditions of ZrO<SUB>2</SUB> formation. The role of SAMs in controlling the size and habit during crystallization of ZrO<SUB>2</SUB> is discussed in terms of a proposed reaction mechanism