Abstract: The invention provides the compounds of formula (): and pharmaceutically acceptable salts thereof, wherein R1, R2, R3, R4, A, X, Y, a, b and n are as defined herein. Also disclosed are methods for making the compounds of formula (I) and their use in treating or preventing diseases associated with cell overproliferation and dysfunctional sphingolipid signal transduction. The invention also encompasses the use of the compounds in combination with an apoptosis-signaling ligand, such as Fas ligand. Preferably, the Fas ligand is administered in the form of a gene therapy agent.

Abstract: The invention provides the compounds of formula ( ): and pharmaceutically acceptable salts thereof, wherein R1, R2, R3, R4, A, X, Y, a, b and n are as defined herein. Also disclosed are methods for making the compounds of formula (I) and their use in treating or preventing diseases associated with cell overproliferation and dysfunctional sphingolipid signal transduction. The invention also encompasses the use of the compounds in combination with an apoptosis-signaling ligand, such as Fas ligand. Preferably, the Fas ligand is administered in the form of a gene therapy agent.

Abstract: A laser cavity is defined by gratings which are selected to provide distributed feed back within the cavity oscillating at a predetermined wavelength. At least one of the gratings deflects a portion of the light wave at an angle to the plane of the active layer to provide surface emission of the laser beam. In order to enhance the output of the laser cavity a further grating is provided on the side of the active layer opposite to the first gratings.