Pulsed I-V and temperature measurement system for characterisation of microwave FETs

Systems for pulsed I-V characterisation of GaAs devices must meet specific requirements concerning not just accuracy and pulse width but also the way the measurements are performed and the definition of various quantities which need to be measured in order to acquire a full picture of the device behaviour. Over the last few years such a system has been iteratively developed and tested at the University of Kent at Canterbury. In the light of the experience gained, a number of new measuring concepts together with some vital observations are presented, raising doubts about the validity of currently existing interpretations of pulsed characteristics. Also the design of an inexpensive system incorporating the new concepts is briefly described.<

Mechanism of drain current droop in GaAs MESFETs

The mechanisms responsible for the drain current droop in GaAs MESFETs are discussed and their relative contributions evaluated. Contrary to a common belief that the cause is mainly self-heating, it is shown on the example of a power MESFET that deep level effects (surface states and bulk traps) have a higher contribution

Synthesis and biological evaluation of pro-drugs of GW196771, a potent glycine antagonist acting at the NMDA receptor

GW196771 is a potent antagonist of the modulatory glycine site of the N-methyl-D-aspartate (NMDA) receptor exhibiting outstanding in vivo profile in different animal models of chronic pain.With the aim to maximize the drug delivery to the target organs a suitable “pro-drug approach” was attempted; in this regards two conjugates of GW196771 with nutrients actively transported into the brain, namely adenosine and glucose, were prepared and investigated. These compounds, were evaluated in vitro in terms of their stability in rat plasma and in vivo on rats. Although an improvement was observed in terms of brain penetration of the esters vs. the parent compound, the amount of the latter did not increase significantly, probably due to some degradation events in the brain, different from the expected ester hydrolysis, resulting in a reduced availability of GW196771