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Introduction Today, due to the increasing application of silver nanoparticles in medical products, it is necessary to pay attention to the user's safety. There are three methods, namely, chemical, physical, and biological, used for the production of nanoparticles. Although the first two methods might introduce health hazards, the latter is hypothetically safe. In this study, we examined the histopathological changes in the cerebellum of neonatal Wistar rats induced by injection of toxic and nontoxic doses of silver nanoparticles, which were produced by green synthetic method and were compared with chemical silver nanoparticles. Methods This study was a laboratory interventional study performed on 25 Wistar rats in the Animal Laboratory of Islamic Azad University of Shahrood. These rats were divided into five groups of the control group, the group with nonpoisonous injection of chemical nanoparticles, the group with nonpoisonous injection of biological nanoparticles, the group with injection of poisonous chemical nanoparticles, and the group with injection of poisonous biological nanoparticles. The rats were impregnated by the males of the same race and the cerebellum of their offspring was studied after birth. Results We found that the injection of nonpoisonous chemical nanoparticles caused hyperemia, inappropriate size, and dark cytoplasm in some Purkinje cells. Also, injection of poisonous chemical nanoparticles caused hyperemia and cellular dispersion in the molecular layer, caused abnormal shapes, and reduced the number of cells in Purkinje cells. However, injection of poisonous and nonpoisonous biological nanoparticles did not alter cerebellum cells nor did it cause any inflammation or hyperemia. Conclusion In contrast with chemical nanoparticles, biological nanoparticles have less significant effect on the cerebellum cells., Examined the histopathological changes in the cerebellum of neonatal wistar rats. Silver nanoparticles which are produced by green synthetic method. In contrast with chemical nanoparticles, biochemical nanoparticles have less significant effect on the cerebellum cells.

A computer model has been developed which simulates both excitation and recovery processes within a block of heart muscle tissue. The model emphasizes the electro physiologic features of repolarization processes. It is comprised of artificial images of myocardial tissue consisting of several thousand elements and introduces phenomena that are omitted or seriously simplified in most of the existing computer models of cardiac electrophysiology. These phetiomeria include the abnormal shapes of action-potential curves corresponding to premature excitation of cells that have not fully recovered, different durations of the repolarization phase in endoepicardial layers of tissue, and the tissue anisotropy of excitation transmission and electric resistivity. The model has been used in several experiments. Results of simulation studies are presented in the form of modelled 3-lead electrocardiographic records. In spite of simple assumptions used at model construction, the results of simulation experiments reproduce natural phenomena. The experimental series include: simulation of regular activation sequences, models of ischemia and infarction, models of pnemature beats, simulation of effects due to fast sequential excitation, and simulation of reentry mechanisms with special reference to the initiation of ventricular fibrillation. The future development of more realistic models of cardiac recovery processes is also discussed.