The disclosure concerns pyrido2,3-dpyrimidine derivatives, their preparation and their therapeutic application, of general formula and acid addition salts, hydrates and solvates thereof, as well as in the form of enantiomers, diastereoisomers and mixtures thereof. The method includes collecting intensity data representative of optical emission spectral wavelengths during a plasma etch process. The light emitting diodes include top-emitting diodes and side-emitting diodes that are arranged on a printed circuit board in a variety of configurations to provide an optimum light pattern. A vertical interconnect process may be used to electrically connect the nonvolatile memory dies to each other, as well as other system components. In an embodiment, the sensitivity of the receiver is increased as a function of time to reduce the likelihood of detecting stray reflections from objects other than the intended target. This invention also discloses methods for preventing neuronal cell death and treating neurological conditions that involve neuronal cell death, particularly neurodegenerative diseases characterized by glutamine or kainate mediated toxicity, such as Huntington’s disease and Alzheimer’s disease.