Morphometric analysis of the lymph system in rat heart during myocardial infarction

Simulation of myocardial infarction in random-bred rats showed that lymph vessels play the leading role in the drainage of the myocardium during the acute period of ischemic damage and compensate for the developing insufficiency of interstitial drainage at the expense of venous component of the coronary bed. A pronounced enlargement of the lymph collectors and I, II, and order III vessels in the left and right ventricles of the heart was detected.

Parenchyma-stroma relationships in the myocardium: alterative insufficiency of cardiomyocytes and morphogenesis of focal cardiosclerosis

Remodeling of the myocardium during focal metabolic damages to cardiomyocytes is determined by contracture injuries to myofibrils, their lump degradation, and development of coagulation necrosis. Reactive changes in the stroma develop over the first hours and manifest in acute hemodynamic disturbances followed by proliferation of connective tissue cells. The immature granulation tissue is formed at the site of myocardial damages. Later this tissue is replaced by the mature connective tissue with the formation of small scars. It should be emphasized that sclerotic changes during remodeling of the myocardium after focal metabolic damages are reversible.

Microstructures and properties of ultrafine-grained pure titanium processed by equal-channel angular pressing and cold deformation

Equal-channel angular pressing (ECAP) has been used to refine the grain size of commercially pure (CP) titanium as well as other metals and alloys. CP-Ti is usually processed at about 400 degrees C because it lacks sufficient ductility at lower temperature. The warm processing temperature limits the ability of the ECAP technique to improve the strength of CP-Ti. We have employed cold deformation following warm ECAP to further improve the strength of CP-Ti. Ti billets were first processed for eight passes via ECAP route Bc, with a clockwise rotation of 90 degrees between adjacent passes. The grain size obtained by ECAP alone is about 260 nm. The billets were further processed by cold deformation (cold rolling) to increase the crystalline defects such as dislocations. The strength of pure Ti was improved from 380 to around 1000 MPa by the two-step process. This article reports the microstructures, microhardness, tensile properties, and thermal stability of these Ti billets processed by a combination of ECAP and cold deformation.