A growing body of evidence supports a nicotinic cholinergic approach to pain management, as neuronal nicotinic receptor agonists have shown efficacy across animal models of both inflammatory and neuropathic pain. However, most of these investigations have focused on the spinal system, and there is to date no report of nicotinic receptor-mediated antinociception in any pain model involving the trigeminal field of innervation. Thus, the purpose of the present studies was to evaluate whether the neuronal nicotinic receptor agonist epibatidine possesses antihyperalgesic activity in the formalin model of facial pain. Adult, male, Sprague--Dawley rats received a 50-microl, subcutaneous injection of 5% formalin into one vibrissal pad and the consequent, facial grooming behavior was monitored. Consistent with previous investigations using the formalin model, animals exhibited two periods of nocifensive grooming: (1) an acute phase that began immediately, peaked at 3 min and almost completely abated by 6 min, and (2) a tonic phase that began between 6 and 9 min, peaked at 21 min and slowly diminished over the ensuing 24 min. The subcutaneous administration of epibatidine (1--5 microg/kg) 5 min prior to the formalin injection led to a significant, dose-dependent reduction of both the acute and tonic phases of hyperalgesia. Separate groups of animals receiving epibatidine either 15, 30 or 60 min prior to the formalin injection exhibited a progressively diminishing antihyperalgesic response that was no longer significant in either phase by 30 min. Finally, pretreatment with the selective neuronal nicotinic receptor antagonist mecamylamine completely abolished the antihyperalgesic effect of epibatidine in both phases. Taken together, these studies demonstrate that in both the acute and tonic phases of the formalin model of facial pain, epibatidine produces a neuronal nicotinic receptor-mediated antihyperalgesia that is both dose- and time-dependent. These results support the rationale for exploring the clinical efficacy of nicotinic agonists as analgesics to treat certain types of trigeminal pain in humans.
: The rate of infusion into distilled water of caþ eine and of Mg, Mn, K and P have been measured. The coþ ee used was roasted Kenyan Arabica coþ ee, ground, and sieved to a size range of 1.70-2.00 mm. The analytical techniques employed were HPLC for the analysis of caþ eine and ICP-AES for analysing mineral ions. The kinetic data have been interpreted in terms of a steady-state theory, and the rate constants of infusion have been calculated. The diþ usion coefficients of the various species within the bean were calculated from the resultant rate constants. These values have been compared with the corresponding diþ usion coefficients in pure water at 80ÄC and the hindrance factors in the bean have been determined.
The Linear Synchronous Motor (LSM) has been used for several high speed maglev applications but only recently have developers applied it to urban transit. MagneMotion has worked with the Federal Transit Administration (FTA), as part of their Urban Maglev Project, to develop an LSM propelled maglev transit system called M3. The top speed is only half that of the Transrapid maglev trains now operational in China but by using small vehicles with short headway and rapid acceleration it is possible to achieve outstanding performance at much lower cost. The combination of LSM technology and small vehicles is a cost effective replacement for rotary motor and Linear Induction Motor (LIM) powered trains for all transit applications, including conventional rail and monorail. LSM is the enabling technology that makes it economically and technically feasible to achieve high capacity with short vehicles and, conversely, the use of small vehicles makes LSM propulsion economically attractive. Small vehicles operating with short headway and organized in clusters can achieve high capacity without offline loading. Very precise position sensing and guideway based propulsion and control make short headways safe and affordable. This paper describes the objectives of the MagneMotion LSM development, discusses some of the design features, and presents 3 examples. The examples are based on operational speeds up to 60 m/s (134 mph), accelerations up to 0.16 g, vehicle headways down to 4 seconds, and capacities up to 12,000 passengers per hour per direction (pphpd). Examples include a 1 mile high capacity shuttle, a 4 km unidirectional loop with several stations, and a 30 km high-speed airport connector. Calculations show that an LSM propelled transit system has lower capital cost than conventional transit systems using vehicle-based electric propulsion with either rotary motors or LIMs. Vehicles are simplified, the cost of energy and maintenance is reduced and, most important, users of the transit system experience major reductions in trip times.
The MagneMotion Maglev system, called M3, is an alternative to all conventional guided transportation systems. Advantages include major reductions in capital cost, travel time, operating cost, noise, and energy consumption. Vans or small-bus size vehicles operating automatically with headways of only a few seconds can be moved in platoons to achieve capacities of at least 12,000 passengers per hour per direction. Small vehicles lead to lighter guideways, shorter waiting time for passengers, lower power requirements for wayside inverters, more effective regenerative braking, and reduced station size. The design objectives were achieved by taking advantage of high-energy permanent magnets, improved microprocessor-based power electronics, precise position sensing, lightweight vehicles, a guideway matched to the vehicles, and the ability to use sophisticated computer-aided design tools for analysis, simulation, and optimization. Arrays of permanent magnets on both sides of a vehicle provide suspension, guidance, and a field for linear synchronous motor propulsion. Feedback-controlled current in control coils wound around the magnets stabilizes the suspension. The motor windings are integrated into suspension rails and excited by inverters along the guide-way. M3 is designed to provide speeds up to 45 m/s (101 mph) and acceleration and braking up to 2 m/s2 (4.5 mph/s) without onboard propulsion equipment. Operating speeds and accelerations can be modified by changing only the power system and wayside inverters. Capital cost, travel time, and operating cost are predicted to be less than half that of any competing transit system.
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