Glue, function

It is thought that the function of the glue or gelatin is to combine with very slight traces of heavy metal cations, for example Cu, which are known to catalyse the nitrogen-forming reaction. 

Present-day nomenclature is partly the result of the conflict and interplay of two functions the need to communicate in speech and on the printed page on the one hand, and the need for archival storage of information and its efficient, reliable retrieval. The former function came first, and laid the basis for the nomenclature most commonly used even today, and gave birth to a wealth of trivial names (i.e. names that give little or no information on structure). These were often coined on the basis of the origin of the substance, as in the case of collidine, obtained from distillation of bones in glue factories, or were derived from a special characteristic, as in the case of skatole, which has a fecal odor. Such names are short and generally euphonious, but they must be memorized they cannot be deduced from the structure. 

In the manufacture of pure resorcinol resins, the reaction can be violently exothermic unless controlled by the addition of alcohols. Because the alcohols perform other useful functions in the glue mix, they are left in the liquid adhesive. PRF adhesives are generally prepared firstly by reaction of phenol with formaldehyde to form a PF resol polymer, that has been proved to be in the greatest percentage, and often completely, linear [95], In the reaction step that follows the resorcinol chemical is added in excess to the PF-resol to react it with the PF-resin -CH2OH groups to form PRF polymers in which the resorcinol groups can be resorcinol chemical or any type of resorcinol-formaldehyde polymer. 

Substances which function as tissue adhesives have the unique ability to remain in contact with tissues in localized areas for prolonged periods of time. Not only does the tissue adhesive function as a glue but it has the capacity to serve as a slow release mechanism for drug delivery as it is biodegraded. 

Meredith TJ, Ruprah M, Liddle A, et al Diagnosis and treatment of acute poisoning with volatile substances. Hum Toxicol 8 277-286, 1989 Merry J, Zachariadis N Addiction to glue sniffing. Br Med J 5317 1448, 1962 Mihic SJ Acute effects of ethanol on GABAA and glycine receptor function. Neuro-chemint 35 115-123, 1999... 

The main handicap of MD is the knowledge of the function [/( ). There are some systems where reliable approximations to the true (7( r, ) are available. This is, for example, the case of ionic oxides. (7( rJ) is in such a case made of coulombic (pairwise) interactions and short-range terms. A second example is a closed-shell molecular system. In this case the interaction potentials are separated into intraatomic and interatomic parts. A third type of physical system for which suitable approaches to [/( r, ) exist are the transition metals and their alloys. To this class of models belong the glue model and the embedded atom method. Systems where chemical bonds of molecules are broken or created are much more difficult to describe, since the only way to get a proper description of a reaction all the way between reactant and products would be to solve the quantum-mechanical problem at each step of the reaction. 

Fig. 2.3.7 Lower GARField profiles showing a UF (urea formaldehyde) glue line acting as a barrier to water transport for up to 24 h. The glue line is at 800 pm on the scale. Wood is above and below this. The water reservoir is beyond 1300 pm. The profiles shown were recorded after 20 (thin line), 100 and 1400 (thick line) min of exposure to water. Upper plots of the magnetization signal intensity in the lower and upper wood layers as a function of time for three glues urea formaldehyde (squares), phenolic resorcinol formaldehyde (triangles), and poly (vinyl acetate) (diamonds).

Glue components can be built to translate the concepts and adapt the connectors in the simplest case, the users can perform those functions. 

Whereas the range of uses to which resin exudates and tar-pitch extractives has been emphasized, some of these functions could have been plausibly served by a range of other natural products. For example, knowledge of other prehistoric adhesives could be biased by the poor survival of protein-based (such as fish, bone and horn) glues. However, it should be remembered that these substances... 

An alternate approach, which has proven to be extremely useful for metals, has been developed by Daw, Baskes and Foiles - (and to a lesser extent, by Ercolessi, Tosatti and Parrinello ). Called the embedded atom method (EAM) (or the glue model by the second group), the interactions in this approach are developed by considering the contribution of each individual atom to the local electron density, and then empirically determining an energy functional for each atom which depends on the electron density. This circumvents the problem of defining a global volume-dependent electron density. 

Severe but reversible liver and kidney injury occurred in a person who was a glue sniffer for 3 years. The chief component of the inhaled solvent was toluene (80% vol/vol) other ingredients were not listed. In workers exposed for many years to concentrations in the range of 80-3 00 ppm, there was no clinical or laboratory evidence of altered liver function. ... 

Glue P, Nutt D Clonidine challenge testing of alpha-2-adrenoceptor function in man the effects of mental illness and psychotropic medication. J Psychopharmacol (Oxf) 2 119-137, 1988... 

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