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Hypoglycemic

Hypoglycemic

Basically the idea is justified, and while there were no more effective drugs, salol had a relatively wide application. The principle itself Nentski ('salolovy principle'), by essentially formed the basis for a further so-called 'prodrugs'. Despite the fact that over time the main role in the creation of new drugs have played a variety of scientific principles, empirical search for drugs values are completely lost. And now, continue to be identified pharmacologically active products of natural origin (from plants, fungi, marine products, etc.). Screening (pharmacological 'screened') are new synthetic compounds which have no analogues among the known compounds. In these cases, the success of the search depends on the amount of screening: the more used methods, the greater the chance of detection one or another type of pharmacological activity. One option for accidental discovery of medical activity is the so-called 'serendipity', when the study of drug action on the testimony of a single detected his other valuable medicinal properties.

Since it was found antidepressant effects of iproniazid, the hypoglycemic effect of sulfonamides and some other effective drugs. One of the major principles a drug is a selection of existing 'beginning' of the products of natural origin. This principle originates from the time of discharge from the opium morphine (1806). Since then, a large number of plants selected alkaloids (atropine, caffeine, cocaine, pilocarpine, physostigmine, platifillin, galantamine, vinblastine, and many others), glycosides (digitoxin, digoxin, strophanthin, etc.), saponins, terpenes, coumarins and other substances that have found use as medicines. Search and study of existing 'started' plant is still ongoing.

Torsion

Torsion

State of stress in shear. Pure shear. Principal stresses. Mohr diagram. Displacement and deformation under shear (absolute and relative changes). Immutability of the shift. Hooke's Law for the shift. Shear modulus.

The strain energy in shear. Dependence between the elastic constants E, G and m for an isotropic material. Estimated equation for shear strength. Permissible shear stress. Practical calculations of riveted joints in shear and crushing. Topic 6. Torsion Torsion of a straight rod round cross-section. The main hypothesis.

Power factors in the cross section under torsion. Torque curve. Determination of stress in cross-section torsional rod. Diagram of shear stresses. Stress state under torsion. The angle of twist. Stiffness of the rod under torsion. The strain energy torsional rod. Estimated equation for strength and rigidity. The torque on given the power transferred shaft, and shaft speed. Theme 7. Direct bending loads that cause bending of the rod. Supports and support reactions of beams. Types of statically determinate beams. Calculation of reaction supports. Power factors in the general the case of direct bending. Transverse and pure bending. Differential relationship between the bending moment, shear force and intensity of distributed transverse load. Construction diagrams of shear forces and bending moments. Control the correctness of the construction of diagrams of the force factors in bending. Pure bending of a straight rod of constant section. The geometry of the deformation beams. Neutral layer beams. Neutral axis (line) cross-section beams. Assumptions involved in the theory of pure bending. Determination of normal stress in pure bending.