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Summit Safety has developed a non-contact, ultrasound-based sensor capable of detecting small changes in position of a structure and small vibrations that may be precursors of structural collapse. The sensor uses two ultrasonic transducers - one for transmit, and one for receive - and processes the return echo in a manner similar to that of a laser interferometer to generate high-resolution position, velocity, and acceleration information about structural surfaces. By using ultrasound, the sensor operates even in the presence of thick smoke, dust, or fog, which could render an optical or laser-based system unusable. Because the sensor is non-contact, it can be installed quickly and potentially out of harm's way. Installation and alignment of the sensor can be accomplished in a matter of seconds. Summit Safety received initial funding from NIST and follow-on phase 1 and phase 2 SBIR contracts from DHS to continue the development of the monitoring system. Phase 1 focused on analyzing the accuracy and performance limitations of the sensor. phase 1 further identified particular collapse scenarios and different types of structures in order to best utilize the measurement capability of the system for collapse detection and prediction. During phase 2 (currently in process) the system is being converted from an engineering tool to a system capable of providing real-time measurement of structural stability and advanced warning of pending collapse for first responders and emergency personnel. The system will display structural stability data from wireless sensors on a central display system.

One hundred and ten patients with trigeminal neuralgia were treated with the Gamma Knife using a single isocenter, the 4 mm secondary collimator helmet and a radiosurgical dose maximum of 70 or 80-Gy. The isocenter was placed at the trigeminal sensory root adjacent to the pons as identified on stereotactic MRI scans. Follow-up periods range from 4–49 months (mean 19.8 months). Initial pain relief was achieved in 95.5% of patients with typical trigeminal neuralgia symptoms, who had not had prior surgical intervention, and only 3.3% of these patients experienced recurrent pain during the follow-up period. Patients with atypical features to their pains or who had prior unsuccessful surgical attempts to relieve their pains achieved initial and long-term pain relief in 88 and 69%, respectively. Three patients (2.7%) developed delayed loss of facial sensation following treatment, but no other complications of any kind were noted. We believe that Gamma Knife radiosurgery is the safest and most effective form of treatment which is currently available for trigeminal neuralgia. We recommend early radiosurgical treatment of trigeminal neuralgia once the diagnosis is clearly established.

IN mid 1963 the Guided Weapons Division of the British Aircraft Corporation was charged with the problem of producing a nose radome for the Concorde supersonic transport.

The effect of monopolar and bipolar dental pulp stimulation and mechanical facial stimulation on the level of excitability of trigeminal primary afferent fibres was studied. Mechanical facial stimulation resulted in increased excitability of trigeminal primary afferents. Monopolar dental pulp stimulation resulted in a period of increased excitability similar in amplitude and time course to that with mechanical stimulation. This excitability increase was reduced in amplitude, but not abolished, in both cases by dorsolateral medullotomy at the level of the obex. Bipolar dental pulp stimulation resulted in a brief early period of increased excitability of lower amplitude than that seen with monopolar stimulation. This was followed by a prolonged consistent period of decreased excitability. Monopolar dental pulp stimulation also elicited a late period of decreased excitability, but it was inconsistent and of much lower amplitude than that seen with bipolar stimulation. Dorsolateral medullotomy at the level of the obex abolished the excitability decrease seen with both types of dental pulp stimulation. We suggest that monopolar dental pulp stimulation activated large mechanoreceptive periodontal afferent fibres, in addition to pulp fibres, with resultant primary afferent depolarization. Bipolar stimulation apparently activated afferents which were confined almost exclusively to the pulp and resulted in primary afferent hyperpolarization. These results suggest that studies which employ electrical stimulation of dental pulp as a painful stimulus should use exclusively bipolar stimulation, whenever possible. Studies of the sensation or physiologic changes evoked by dental pulp stimulation are difficult to interpret if monopolar stimulation is used. For strictly clinical localization of teeth with pulp pathology, however, the monopolar algesiometers used at present are probably satisfactory.