Adventures in the pharmacological analysis of P2 receptors

The pharmacological classification of P2 receptors owes its origin to the pioneering efforts of Geoff Burnstock and those who followed him, research that was conducted primarily in physiological experimental systems. Over recent years, the techniques of molecular biology have been increasingly applied in the study of P2 receptors while, at the same time, advances in their pharmacological analysis have been limited by a lack of potent and selective agonist or antagonist ligands. This has resulted in a classification scheme which is largely structural in nature, with relatively little contribution from pharmacology. Our endeavours in this area have been directed towards the discovery of ligands with which the pharmacological analysis and definition of P2 receptors could be advanced, the ultimate goal being the design of therapeutic agents. This article will describe some of our experiences in this challenging but rewarding Nea. (C) 2000 Elsevier Science B.V. All rights reserved.

The electrical characterization and response to hydrogen of Schottky diodes with a resistive metal electrode—rectifying an oversight in Schottky diode investigation

Schottky-barrier structures with a resistive metal electrode are examined using the 4-point probe method where the probes are connected to the metal electrode only. The observation of a significant decrease in resistance with increasing temperature (over a range of similar to 100 K) in the diode resistance-temperature (R(D)-T) characteristic is considered due to charge carrier confinement to the metal electrode at low temperature (high resistance), with the semiconductor progressively opening up as a parallel current carrying channel (low resistance) with increasing temperature due to increasing thermionic emission across the barrier. A simple model is constructed, based on thermionic emission at quasi-zero bias, that generates good fits to the experimental data. The negative differential resistance (NDR) region in the R(D)-T characteristic is a general effect and is demonstrated across a broad temperature range for a variety of Schottky structures grown on Si-, GaAs- and InP-substrates. In addition the NDR effect is harnessed in micro-scaled Pd/n-InP devices for the detection of low levels of hydrogen in an ambient atmosphere of nitrogen.

A conceptualization of the determinants of small business website adoption

As evidence mounts on the importance of small businesses and the opportunities presented by website adoption globally, it becomes important to understand the key issues that determine website adoption. However, the extant literature relating to small business website adoption is fragmented and fails to provide an understanding of what determines adoption.Therefore the key contribution of this article to current knowledge is the development of a conceptualization, supported by the literature, that will provide an interpretation of what determines small business website adoption. Critically, this is the first article to incorporate the important role that the small business marketing context plays within Internet technology adoption. The article develops nine hypotheses, which relate to the critical interactions and integration, within and between four determinant groupings underpinning the conceptualization.The nine hypotheses will guide and direct future research towards generating an empirically based understanding of what determines small business website adoption.