0000000000805581
AUTHOR
Dirk Richter
Extended gate electrode arrays for extracellular signal recordings
Abstract We have fabricated arrays of planar gold electrodes arranged in a matrix of 8×8 with active areas ranging from 6 to 30 μm in diameter. An electronic amplification circuitry based on commercial junction field-effect transistors was used where the gold sensor fields act as extended gate electrodes (EGE) of the transistors, which leads to a new approach for long-term extracellular recording systems in vitro. The high input resistance of the amplification circuitry allows the use of small planar bare gold electrodes without further modification which therefore extends the frequency range of the measuring set-up down to the DC-level. The performance of our recording system has been test…
New sunphotometer for network operation.
A handheld sunphotometer has been developed and is described. It operates for 9 wavelengths in the visible and near infrared. The sensitivity range is rather broad, so it can be used in turbid as well as clear atmospheres. The operation is simple, and a digital readout helps prevent operator biases. The instrument is sun powered and suitable for network operations. Determination of the atmospheric turbidity due to aerosol and the column content of O3, NO2, H2O is possible.