From Big Medical Encyclopedia

MECHANOCHEMICAL PROCESSES — chemical transformations in any chemical, physicochemical or biochemical system under the influence of mechanical forces (forward mechanochemical changes), and also commission by system of mechanical work due to change of energy of chemical bonds in it (the back mechanochemical changes). Reaction of mechanochemical polymerization of special glue of a tsiakrin under the influence of ultrasound can be an example of L. S. that finds application in surgical practice during the «welding» of bones and soft tissues.

Mechanochemical transformations are used for the directed change of properties of various materials of a pla of receiving new.

Mechanisms of course of L. S. are various. So, in uprugonapryazhenny material at action of mechanical forces activation energy of chemical reaction decreases. At the same time there can be a local temperature increase and (or) pressure and as a result of it initiation or acceleration of chemical reaction (see. Cavitation ). In the field of application of mechanical forces can proceed as processes of mechanodestruction (a rupture of molecular linkages), and processes of mechanosynthesis. The direction, speed and energy effeciency of mechanochemical reaction depend on size and duration of action, a condition of system, etc. The rupture of molecular linkages under the influence of mechanical forces can give to - to destruction of system, napr, gel — sol (see. Thixotropy ), to destruction of membranes of bacterial and other cells under the influence of ultrasound, and also to initiation and activation of chemical reactions by active particles (radicals, ions) arising at a rupture of molecular linkages.

The back mechanochemical reactions — emergence of deformation of substance under the influence of chemical reagents (e.g., reduction of volume of aktomiozinovy gel under the influence of ATP, ability of polyelectrolytes to be twisted or stretch at change of pH of the environment etc.) — are of great importance for polymer chemistry and biology.

The m of the item causing changes of a form of organisms and their ability to movement have wide biol, distribution. M of the item are found in a number of plants (e.g., a mimosa bashful, insectivorous plants, etc.), microorganisms (ciliate, flagellar), at animals, to-rye have vocational educations for the movement. In an organism of high-organized animal L. S. are inherent not only to special cells (muscle cells), ache to subcellular structures (to a mitochondrion, kernels etc.).

The most specialized mechanochemical system in an organism is the muscle capable to transformation of energy of hydrolysis adenosine triphosphoric to - you in mechanical energy that leads finally to shortening of a muscle (see. Muscular contraction ) and to commission of work (see. Muscular work ). Studying of features of L. S. in a muscle is of huge interest since the muscle is the economic and reliable «engine» which is carrying out highly effective direct transformation of chemical energy into mechanical work at a temperature and pressure close to normal.

Assume that mechanoreceptions are the cornerstone forward mechanochemical reactions (see. Mechanioreceptors ).

Bibliography: Baramboym N. K. Mechanochemistry of high-molecular compounds, M., 1971, bibliogr.; Hoffman E. G. Dynamic biochemistry, the lane with it., M., 1971, bibliogr.; 3 and and l and sh in silt and M. M. Physical and chemical bases of muscle performance, Tbilisi, 1971, bibliogr.; M and r at l and with M. A. Modern ideas of the nature sound-himiche-skikh reactions, Zhurn, fizich. chemical, t. 50, century 1, page 1, 1976, bibliogr.

V. B. Akopyan.