Tonic character

In case of acute poisoning with OPC (phosphacol, DPP, sarin, tabun, parathion, DDVP, hostaquick, etc ), the clonic/tonic character of convulsions indi-... 

The Aristolochias are used in medicine as tonics due to the presence of bitter principles, though Hesse suggested that A. reticulata Nutt, then the serpentary root of commerce, might contain aristolochine, and the view that the bitter constituents are of alkaloidal character has been confirmed by Krishnaswamy, Manjunath and Rao, for A. indica L. 

The normally harmonious music of the aminergic neuronal spheres is contrapuntal to the brain stem cholinergic system, whose modulatory output is generally reciprocal to the aminergic groups and distinctly phasic and burstlike in character (rather than tonic and regular). In fact, the phasic bursts of acetylcholine (ACh) neuronal discharge appear to be strictly and precisely related to eye movement control by the paramedian reticular formation and the oculomotor system. 

Experimental Results. The DLVO theory, which is based on a continuum description of matter, explains the nature of the forces acting between membrane surfaces that are separated by distances beyond 10 molecular solvent diameters. When the interface distance is below 10 solvent diameters the continuum picture breaks down and the molecular nature of the matter should be taken into account. Indeed the experiment shows that for these distances the forces acting between the molecularly smooth surfaces (e.g., mica) have an oscillatory character (8). The oscillations of the force are correlated to the size of the solvent, and obviously reflect the molecular nature of the solvent. In the case of the rough surfaces, or more specifically biomembrane surfaces, the solvation force displays a mono tonic behavior. It is the nature of this solvation force (if the solvent is water, then the force is called hydration force) that still remains a puzzle. The hydration (solvation) forces have been measured by using the surface force apparatus (9) and by the osmotic stress method (10, II). Forces between phosphatidylcholine (PC) bilayers have been measured using both methods and good agreement was found. 

The differences in the electronegativities of two atoms in a molecule can be used to estimate bond strengths and bond tonicities (i.e., the percentage of ionic character in the bond—the extent of mixed bonding see Section 4.6 for numerical examples). 

Two of the BChl chromophores squeeze into a protein cavity and form a skewed SP dimer. The distance between the Mg ions of the monomers is 8 A. The geometry is favorable for the formation of a low-energy excited state that contains both exci-tonic and charge transfer characters. 

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