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Background. Penetrating eye injuries are the most serious damage in ocular trauma. They constitute, according to different authors, from 41,4% to 93,5% in the structure of ocular injuries. Corneal penetrating injury accounts 22,5-63%. Objective. Histologic and ultrastructural evaluations of scar in the cornea after penetrating eye injury. Methods. As the object of the study were used corneas over 12 month after penetrating corneal injury. The corneas were trisected and processed for conventional histologic analysis and transmission electron microscopy. Results. This study showed that the thickness of the cornea at the site of the scar after penetrating trauma over 9-12 months was less on 24.2% than in the adjacent intact tissue. Scaring tissue did not contain normal lamellae and lost their correct orientation. Stroma of the scar was composed from disorganized tightly packed fibrils and connective tissue cells (keratocytes and myofibroblasts). Conclusion. The repair of the cornea accompanied by specific problems: disorganization of the stroma reduces cornea transparency; contraction of fibrous scar tissue during the remodeling leads to optical aberrations. On the other hand, such a dense structure of the scar provides a relatively favorable condition for the reconstruction and reorganization of adjacent areas of the stroma and may also inhibit swelling of the stroma. Corneal wound healing occurs through a series of steps: activation of repair (corneal injury, proliferation and migration of corneal epithelial cells, stromal keratocytes, endothelial cells; cellular differentiations with active reduction, synthesis and accumulation of extracellular matrix) and tissue remodeling. Citation: Ivanchenko MV, Galayda NA. [Morphological evaluation of scar tissue and corneal layers after penetrating eye injury]. Morphologia. 2015;9(4):31-6. Russian.

Background. Ultrastructure of mitochondria depends on the functional load on the organelle and is characterized by dynamic changes in the outer, and particularly the inner mitochondrial membrane, cristae and cause changes in the intensity of ATP synthesis and normal contractile function of the heart. Objective. Analysis of the ultrastructural rearrangement of mitochondria in the rat ventricular contractile cardiomyocytes at the prenatal ontogenesis in conditions of chronic intrauterine hypoxia. Methods. White rats were used as a material. Intrauterine hypoxia was modeled by intraperitoneal injection of sodium nitrite on the 10th and 21st day of pregnancy. Embryonic hearts on the 14th, 16th, 18th and 20th days of prenatal ontogenesis were investigated with the help of transmission electron microscopy. Packaging and quantitative density of mitochondria were estimated. Results. It was shown that during prenatal ontogenesis the structure of individual mitochondria and mitochondrial network significantly changes. Heterogeneity of the organelles and their localization in the cell reflects a specific response of mitochondria on the pathological process. On early stages of rat embryogenesis morphological and ultrastructural changes in mitochondrial network are more prominent in the contractile cardiomyocytes of the right ventricle comparing with the parameters of the left ventricle. In the same manner changes in the subsarcolemmal and intermyofibrillar regions are more significant than in the intracellular localized mitochondria and result in decrease of mitochondrial growth parameters and development of heterogeneity of organelles. Conclusion. Under the hypoxic conditions during rat prenatal ontogenesis the most significant processes of mitochondria destruction takes place in the subsarcolemmal and intermyofibrillar regions of cardiomyocytes of left ventricle.

Changes of cardiomyocytes mitochondrial apparatus can be marked as the main factors which are the basis of various forms of cardiovascular disease, but the dynamics of morphogenetic rearrangements heart mitochondria are poorly researched under normal conditions and under the influence of harmful factors. Mitochondria of contractile cardiomyocytes are different in their morphology and localization in the cell, the biochemical properties and are able to form differently association with other intracellular structures. Question of the relationship between function and heterogeneity of regional specialization of mitochondria and the realization of the heterogeneity in the cell and the degree of their dependence on the disease during ontogeny is important and relevant. There are relatively few ultrastructural studies that investigate adaptive techniques and alternative processes in the mitochondria of atrial and ventricular myocardium under prenatal hypoxia during the development of the myocardium. It is interesting to find mechanisms for the implementation of the ultrastructural changes in the mitochondrial apparatus and extracellular tissue levels in hypoxic conditions on the stages of ontogeny.

We have studied ultrastructure of mitochondria in embryos rat’s myocardium at different stages of prenatal ontogenesis. It is shown that in the sarcoplasm of contractile cardiomyocytes determined significant polymorphism of mitochondria, ratio of all types of mitochondria is different of stages of rat’s ontogenesis and is significantly different from those of contractile cardiomyocytes of newborns. Established, that the distribution of different types of mitochondria is heterogeneous in specific subcellular localization, due to the functional features of these organelles. During prenatal development of rat heart is regular increase in the degree of heterogeneity of the mitochondrial apparatus. At the same time, the formation and the degree of development in different parts of the heart are not the same. The most active development rates of mitochondrion occur in the myocardium of the left and right ventricles, the lowest – in the atrial, at the early stages of cardiogenesis by the "low-energy" organelles, then, with a significant increase of the "high-energy" mitochondria.

The Fermi-Pasta-Ulam problem was one of the first computational experiments. It has stirred the physics community since, and resisted a simple solution for half a century. The combination of straightforward simulations, efficient computational schemes for finding periodic orbits, and analytical estimates allows us to achieve significant progress. Recent results on q-breathers, which are time-periodic solutions that are localized in the space of normal modes of a lattice and maximize the energy at a certain mode number, are discussed, together with their relation to the Fermi-Pasta-Ulam problem. The localization properties of a q-breather are characterized by intensive parameters, that is, energy densities and wave numbers. By using scaling arguments, q-breather solutions are constructed in systems of arbitrarily large size. Frequency resonances in certain regions of wave number space lead to the complete delocalization of q-breathers. The relation of these features to the Fermi-Pasta-Ulam problem are discussed. [DOI: 10.1119/1.2820396]

Abstract: Using scanning tunneling microscopy, solid phase epitaxial growth of FeSi2 nanodots on -R30°-B surface has been studied in the temperature range of 400–700°C and Fe coverage of up to 0.5 monolayer. It has been found that density of nanodots formed on -R30°-B surface is essentially higher than that on Si(111)7×7 surface at the same temperature and coverage. Density of the 2×2 islands and structural defects is reduced on -R30°-B surface in comparison with that on Si(111)7×7 surface. [Copyright &y& Elsevier]