Benefit of spatial filtering for visual perception with a subretinal implant.

Subretinal implants have proven to be capable of restoring vision to patients suffering from hereditary retinal degeneration diseases like retinitis pigmentosa and cone-rod dystrophy. Although they already provide basic visual perception, there is still much room for improvement in this field. Effects like electric field interference limit the visual acuity and may be the cause of the perceived vision to be blurred.

Clock recovery PLL with gated PFD for NRZ ON-OFF Modulated Signals in a retinal implant system.

A Clock Recovery Phase Locked Loop with Gated Phase Frequency Detector (GPLL) for NRZ ON-OFF Modulated Signals with low data transmission rates for an inductively powered subretinal implant system is presented. Low data transmission rate leads to a long absence of inductive powering in the system when zeros are transmitted. Consequently there is no possibility to extract any clock in these pauses, thus the digital circuitry can not work any more.

Laser ionization of H2S and ion-molecule reactions of H3S+ in laser-based ion mobility spectrometry and drift cell time-of-flight mass spectrometry.

The detection of hydrogen sulfide (H2S) by 2 + 1 resonance-enhanced multi-photon ionization (REMPI) and the application of H2S as a laser dopant for the detection of polar compounds in laser ion mobility (IM) spectrometry at atmospheric pressure were investigated. Underlying ionization mechanisms were elucidated by additional studies employing a drift cell interfaced to a time-of-flight mass spectrometer. Depending on the pressure, the primary ions H2S(+), HS(+), S(+), and secondary ions, such as H3S(+), were observed.

In vitro study of iridium electrodes for neural stimulation.

Iridium is one of the main electrode materials for applications like neural stimulation. Iridium has a higher charge injection capacity when activated and transformed into AIROF (activated iridium oxide film) using specific electrical signals. Activation is not possible in stimulating devices, if they do not include the necessary circuitry for activation.

An economical and convenient experiment setup for electrode investigation.

Electrodes are among the critical components of neural stimulation devices. Investigating electrode properties like electrode impedance, charge injection capacity, and electrode corrosion limits plays an important role in electrode development. There are many commercial devices available for this purpose.

In vitro study of titanium nitride electrodes for neural stimulation.

For neural stimulation, reliable high density charge transfer into tissue is required. One electrode material for these applications is titanium nitride (TiN). In this paper, a method for lifetime analysis of TiN electrodes is discussed.