Development of Gating Foils To Inhibit Ion Feedback Using FPC Production Techniques

Positive ion feedback from a gas amplification device to the drift region of the Time Projection Chamber for the ILC can deteriorate the position resolution. In order to inhibit the feedback ions, MPGD-based gating foils having good electron transmission have been developed to be used instead of the conventional wire gate. The gating foil needs to control the electric field locally in opening or closing the gate. The gating foil with a GEM (gas electron multiplier)-like structure has larger holes and smaller thickness than standard GEMs for gas amplification. It is known that the foil transmits over 80 % of electrons and blocks ions almost completely. We have developed the gating foils using flexible printed circuit (FPC) production techniques including an improved single-mask process. In this paper, we report on the production technique of 335 μm pitch, 12.5 μm thick gating foil with 80 % transmittance of electrons in ILC conditions.

HSV-1-mediated NGF delivery delays nociceptive deficits in a genetic model of diabetic neuropathy

A previous phase III clinical trial failed to show significant therapeutic benefit of repeated subcutaneous nerve growth factor (NGF) administration in the treatment of diabetic neuropathy. Animal studies have since shown that site-specific viral-mediated expression of NGF in the lumbar dorsal root ganglia prevents peripheral nerve dysfunction associated with chemically induced neuropathy. Using a Herpes simplex virus expression vector, we have investigated the effect of localized NGF expression in a genetic mouse model of progressive diabetic neuropathy, the +/+ Leprdb mouse. We found that site-specific delivery of NGF initially delayed the appearance of hypoalgesia, assessed by the Hargreaves test, by 1 month and effectively attenuated this deficit for 2 months over the approximately 10 months normal life-span of these animals. Once the disease progressed into its more severe stages, NGF, although still capable of altering the electrophysiological profile of the sensory A- and C-fibers and influencing the expression of p75 and substance P in the dorsal root ganglia, could no longer maintain normal nociception. These data suggest that maximal therapeutic benefit in future NGF-based gene therapy trials will be gained from early applications of such viral-mediated neurotrophin delivery.