Fabrication and characterization of PbSe nanostructures on van der Waals surfaces of GaSe layered semiconductor crystals.

The growth morphology, composition and structure of PbSe nanostructures grown on the atomically smooth, clean, nanoporous and oxidized van der Waals (0001) surfaces of GaSe layered crystals were studied by means of atomic force microscopy, x-ray diffractometry,photoelectron spectroscopy and Raman spectroscopy. Semiconductor heterostructures were grown by the hot-wall technique in vacuum. Nanoporous GaSe substrates were fabricated by the thermal annealing of layered crystals in a molecular hydrogen atmosphere. The irradiation of the GaSe(0001) surface by UV radiation was used to fabricate thin Ga(2)O(3) layers with thickness < 2 nm. It was found that the narrow gap semiconductor PbSe shows a tendency to form clusters with a square or rectangular symmetry on the cleanlow-energy (0001) GaSe surface, and (001)-oriented growth of PbSe thin films takes place on this surface. Using this growth technique it is possible to grow PbSe nanostructures with different morphologies:continuous epitaxial layers with thickness < 10 nm on the uncontaminated p-GaSe(0001)surfaces, homogeneous arrays of quantum dots with a high lateral density (more than 1011 cm(−2))on the oxidized van der Waals (0001) surfaces and faceted square pillar-like nanostructures with a low lateral density (∼10(8) cm(−2)) on the nanoporous GaSe substrates. We exploit the 'vapor­liquid­solid' growth with low-melting metal (Ga) catalyst of PbSe crystalline branched nanostructures via a surface-defect-assisted mechanism.

[Intraspinal organ in man]. / Intraspinal'nyi organ cheloveka.

In the ependymal zone of the spinal cord at the LI-SIII level an ependymal glandular organ has been described. Its highest secretory activity coincides with the period of the greatest functional activity of the human reproductive system functioning. Certain stages in development of the organ, its cell composition, blood supply, afferent and efferent innervation have been studied. In secretory cells of the organ peptide with cardio- and vasotonic properties has been identified immunochemically. The action of the organ is considered in connection with role, which the ependymal glands of the brain play in regulation of the organism's function.

[Ultrastructure of cells of the human intraspinal organ]. / Ul'trastruktura kletok intraspinal'nogo organa cheloveka.

In the intraspinal organ at the level of the IV--V lumbar segments of the spinal cord, in 7 women and 8 men (30-45 years of age) certain cells have been studied electron microscopically. According to their ultrastructure, they are divided into ectogliocytes without processes, plasmic and fibrillar astrocytes, mesogliocytes, tissue basophils and cells with signs of secretion. Variability of organells of the secretory cells and their inclusions is connected with production and exocytosis of the secrete.

[Development and functional morphology of the ependymal blood vessels of the lumbosacral spinal cord in human postnatal ontogeny]. / Razvitie i funktsional'naia morfologiia krovenosnykh sosudov épendimy poiasnichno-krestsovogo otdela spinnogo mozga v postnatal'nom ontogeneze cheloveka.

In 200 persons (at the age of newborn up to 96 years) development of extra- and intraependimal blood vessels beginning from the I lumber up to the V sacral segment has been studied by Kampos' method in the author's modification. At the level of the V lumbar segment ultrastructural morphology of the ependimal capillaries has been investigated. By 30-35 years of age, owing to fusion of the intramedullary blood vessels, powerful circular anastomoses are forming around the ependima; they give origin to the intraependimal arterioles. The latter, subdividing into branches, form compact ependimal capillary networks. In elderly and old persons the density of the network of both types of vessels decreases as a result of the involution process. Ependimal gliocytes tightly adjust the capillaries which possess wide pericapillary spaces. In the capillary endothelium endocytosis is definitely seen, there are pores and fenestrae; it is connected with metabolic intensity of the gliocytes and their possible participation in the secretory process.

[Postnatal histogenesis of the ependymal layer of the human spinal cord and its organogenetic transformation]. / Postnatal'nyi gistogenez épendimnoi obolochki spinnogo mozga i ee organogeneticheskie preobrazovaniia u cheloveka.

The structure and histochemistry of the ependymal layer in the spinal cord were studied light optically and electron microscopically at the age of birth up to 96 years in 200 persons of both sex died from various trauma. At 18-20 years of age in the lumbar part (L1-L5), as a result of the subependymal cells proliferation, an abundantly innervated and vascularized intraspinal organ is formed, which has the connective tissue stroma and ectoglial parenchyma. The parenchymal cells are rich in active oxidoreductases and phosphatases, with a well represented granular endoplasmic reticulum, mitochondria, laminar complex and electron opaque inclusions in them, their dynamic changes being connected with the production of Gomori-positive secretion. Certain changes are mentioned in the development of the organ: the initial, early, completed formation and the period of involution.