Stimuli-sensitive structures

In the last two decades, the development of poljoners which change their structures and properties in response to environmental stimuli such as pH, temperature, and light has attracted a great deal of attention (1-3). Such polymers have been called smart polymers, intelligent polymers, stimulus-sensitive pol3uners, or responsive polymers. They have been used in many applications, ranging from bioactive agent delivery to separation (4,5). Various delivery systems based on the smart polymers have been proposed because of their... 

It is interesting that the stimulus compounds used in the study differ widely in their molecular structures, and yet they all interact with antibodies to thaumatin. It is, therefore, probable that a single receptor-structure responds to all sweet stimuli,there being a variation in the relative effectiveness of sweet stimuli across individual nerve-fibers, and the characteristics of all receptor sites do not appear to be identical. Earlier elec-trophysiological studies of single primary, afferent taste-neurons uniformly agreed that individual fibers very often have multiple sensitivities, and that individual, gustatory receptors are part of the receptive field of more than one afferent fiber. " We have yet to learn how these interact, and the nature of their excitatory, or possible inhibitory, relations, or both. 

Different odor substances stimulate different patterns of ORCs in the olfactory epithelium, owing to the different sensitivity spectra of the ORCs (28). The pattern of activity in the epithelium evoked by a particular odor substance constitutes the first molecular image of that stimulus, which represents the determinants of the stimulating molecules (13). Thus, although olfaction is not a spatial sensory modality, in contrast, for example, to vision and somatosensation, the initial representation of an odor stimulus in the olfactory pathway does have spatial structure. 

The sensitivity and selectivity of olfaction and contact chemosensation are due (1) in the brain, to the existence of a neuronal network of neurons tuned to a specific chemical stimulus, and (2) in the periphery, to the existence of olfactory/ chemosensory receptor neurons housed in sensory microorgans called sensilla. The sensilla can best be viewed as simple cuticular porous extrusions that increase the surface that captures airborne odorants or chemicals dissolved in water droplets. They contain the receptive olfactory or chemosensory structures (Schneider, 1969). The olfactory sensilla are most numerous on the antennae and mediate the reception of sex pheromones and plant volatiles, as well as other odorants. Low volatility pheromones may also be detected by contact chemoreceptors on... 

One of the ways of specification of this mechanism can lie in study of relationships of the said sensitivity of energetic materials to their molecular structure [32], thermal reactivity [35,39,52,109-111], sensitivity to mechanic stimuli [32,109,112,113] and detonation characteristics [5,33,34,47]. As already stated, a thermal stimulus could be the basis of electric spark initiation [35,39,52,53],... 

Electrochemical deposition of conjugated polymers occurs easily, but the final properties are sensitive to the deposition conditions, including supporting electrolyte, temperature, electrical stimulus (galva-nostatic, potentiostatic, or potentiodynamic), and electrode material. MEMS developers need to be familiar with how deposition conditions affect film properties, such as conductivity. Young s modulus, and speed. Further details on the effects of electropolymerization conditions on the structure and properties of conducting polymers can be found elsewhere [9]. 

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