In this work, with this biological inspiration, a class of computation devices that consist of neurons and astrocytes is introduced, called spiking neural P systems with astrocytes (SNPA systems). The computation power of SNPA systems is investigated. It is proved that SNPA systems with simple neurons (all neurons have the same rule, one per neuron, of a very simple form) are Turing universal in both generative and accepting modes. If a bound is given on the number of spikes present in any neuron along a computation, then the computation power of SNPA systems is diminished. In
this case, a characterization of semilinear sets of numbers is obtained.”
“A new method for evoking the tail flick reflex is introduced, using short duration or “impulsive” nociceptive stimuli, which allow synchronization and recording click here of electrophysiological responses. Ten adult rats were studied, by means of thermal (CO2 laser infrared pulse with 30 ms duration, 7.5 or 10 W), electric (a 25 ms train of five 0.2 ms pulses, with 5 or 10 mA intensity) or mechanical (pin pressed with 5 g force) stimuli. Both electromyographic and strain gauge mechanical responses were recorded from the tail. All three types of stimulation gave rise to three components, named early, late and ultralate, respectively occurring in the
range of 19-97 ms, 190-519 ms, 1523-2765 ms. Conduction velocities of the underlying afferent fibres were calculated by moving the stimulation site. The early component could be linked to A delta Milciclib mouse afferents, while late and ultralate components were due to unmylinated C afferents. Experiments with Fentanyl (20 mu g/kg)
showed that only the C linked components were depressed, with the ultralate component the most affected, possibly because supraspinally originated. Tail flick reflex evoked by impulsive stimuli is believed to be an important electrophysiological complement to behavioural procedures, useful in identifying the site of action of analgesics and other drugs upon the spinal and supraspinal centres involved in nociception. (C) 2011 Elsevier B.V. All rights reserved.”
“High-density polyethylene/wood flour (HDPE/W-F) composites were prepared by a twin-screw extruder. The effects of WF, silane coupling agents, polymer compatibilizers, and their content on the comprehensive properties ZD1839 price of the WF/HDPE composites have been studied in detail, including the mechanical, thermal, and rheological properties and microstructure. The results showed that both silane coupling agents and polymer compatibilizers could improve the interfacial adhesion between WF and HDPE, and further improve the properties of WF/HDPE composites, especially with AX8900 as a compatibilizer giving higher impact strength, and with HDPE-g-MAH as a compatibilizer giving the best tensile and flexural properties. The resultant composite has higher strength (tensile strength = 51.