Atomic, electronic and transport properties of In-Au 2D compound on Si(1 0 0).

Two-dimensional (In, Au)/Si(1 0 0)c(2 [Formula: see text] 2) compound was synthesized and its atomic arrangement, electron band structure and low-temperature transport properties were characterized using scanning tunneling microscopy, angle-resolved photoelectron spectroscopy and four-point-probe resistivity measurements assisted with first-principles density-functional-theory calculations. The present results are compared to those obtained earlier for the parent (Tl, Au)/Si(1 0 0)c(2 [Formula: see text] 2) system.

Electronic properties of the two-dimensional (Tl, Rb)/Si(1 1 1)[Formula: see text] compound having a honeycomb-like structure.

Heavy metal layers having a honeycomb structure on the Si(1 1 1) surface were theoretically predicted to show prospects for possessing properties of the quantum spin Hall (QSH) insulators. The (Tl, Rb)/Si(1 1 1)[Formula: see text] atomic-layer compound synthesized in the present work is the first real system of such type, where atoms of heavy metal Tl are arranged into the honeycomb structure stabilized by Rb atoms occupying the centers of the honeycomb units. Electronic properties of the (Tl, Rb)/Si(1 1 1)[Formula: see text] compound has been fully characterized experimentally and theoretically and compared with those of the hypothetical (Tl, H)/Si(1 1 1)[Formula: see text] prototype system. It is concluded that the QSH-insulator properties of the Tl-honeycomb layers on Si(1 1 1) surface are dictated by the stable adsorption sites occupied by Tl atoms which, in turn, are controlled by the atom species centering the Tl honeycombs. As a result, the real (Tl, Rb)/Si(1 1 1)[Formula: see text] compound where Tl atoms occupy the T4 sites does not possess QSH-insulator properties in contrast to the hypothetical (Tl, H)/Si(1 1 1)[Formula: see text] system where Tl atoms reside in the T1 (on-top) sites and it shows up as a QSH material.

From C60 "trilliumons" to "trilliumenes:" Self-assembly of 2D fullerene nanostructures on metal-covered silicon and germanium.

We discovered a set of C60 nanostructures that appear to be constructed using a universal building block made of four C60 molecules on Si(111) or Ge(111) surfaces covered by an atomic layer of Tl, Pb, or their compound. The building block is a four-C60 cluster having a shape reminiscent of the three-petal flower "white trillium." Therefore, we call it "trilliumon" and the various 2D ordered nanostructures derived from it "trilliumenes." Self-assembly of the trilliumenes is a result of an intricate interplay among the adsorbed C60 molecules, metal atoms, and semiconductor substrates. Remarkably, all metal layers triggering formation of trilliumenes on the Si(111) surface have recently been reported to be the thinnest 2D superconductors. In this respect, the trilliumenes show promise to be 2D nanostructured superconductors whose properties are awaiting their exploration.

(Tl, Au)/Si(1 1 1)[Formula: see text] 2D compound: an ordered array of identical Au clusters embedded in Tl matrix.

Formation of the highly-ordered [Formula: see text]-periodicity 2D compound has been detected in the (Tl, Au)/Si(1 1 1) system as a result of Au deposition onto the Tl/Si(1 1 1) surface, its composition, structure and electronic properties have been characterized using scanning tunneling microscopy, angle-resolved photoelectron spectroscopy and density-functional-theory calculations. On the basis of these data, the structural model of the Tl-Au compound has been proposed, which adopts 12 Tl atoms and 10 Au atoms (in total, 22 atoms) per [Formula: see text] unit cell, i.e. ∼1.71 ML of Tl and ∼1.43 ML of Au (in total, ∼3.14 ML). Qualitatively, the model can be visualized as consisting of truncated-pyramid-like Au clusters with a Tl atom on top, while the other Tl atoms form a double layer around the Au clusters. The (Tl, Au)/Si(1 1 1)[Formula: see text] compound has been found to exhibit pronounced metallic properties at least down to temperatures as low as ∼25 K, which makes it a promising object for studying electrical transport phenomena in the 2D metallic systems.

New method for MBE growth of GaAs nanowires on silicon using colloidal Au nanoparticles.

We present a new method for the deposition of colloidal Au nanoparticles on the surface of silicon substrates based on short-time Ar plasma treatment without the use of any polymeric layers. The elaborated method is compatible with molecular beam epitaxy, which allowed us to carry out the detailed study of GaAs nanowire synthesis on Si(111) substrates using colloidal Au nanoparticles as seeds for their growth. The results obtained elucidated the causes of the difference between the initial nanoparticle sizes and the diameters of the grown nanowires.

Repeated administration of ethambutol in therapeutic dose causes testes alteration and spermatogenesis disruption in Wistar rats.

Ethambutol (EMB) is conventionally used to treat tuberculosis and atypical Mycobacterium infections in combination with other antimycobacterial drugs. Eventually, EMB testicular toxicity has not been explored extensively yet. The aim of the study is to evaluate testicular toxicity of EMB. We explored the impact of EMB on male rats' fertility, testosterone level and germ cells state, testicular pro- and anti-oxidant status and DNA damage, as well as identified EMB effects on cytochrome P-450 2E1 (CYP2E1) both with computer simulation and in vivo. We demonstrated that EMB administration to male rats decreased in epididymal sperm count (19%) and fertility index (53%). These events were accompanied by reduction in serum testosterone content (1.6 times) and appearance of spermatogenic epithelium damages. It was also found in testes the intensification of lipid peroxidation, decrease in reduced glutathione content and changes in DNA fragmentation. Additionally, computer simulation showed direct interaction of EMB with CYP2E1 active site and heme. On the top of this, we demonstrated that level of testicular CYP2E1 messenger RNA in EMB-treated rats was increased 8.7 folds and p-nitrophenol hydroxylase activity in testes rose three folds. As this shows, EMB-caused CYP2E1 induction, oxidative stress, and apoptosis in the testes contribute to inhibition of steroidogenesis enzymes and spermatogenesis disruption.

2D Tl-Pb compounds on Ge(1 1 1) surface: atomic arrangement and electronic band structure.

Structural transformations and evolution of the electron band structure in the (Tl, Pb)/Ge(1 1 1) system have been studied using low-energy electron diffraction, scanning tunneling microscopy, angle-resolved photoelectron spectroscopy and density functional theory calculations. The two 2D Tl-Pb compounds on Ge(1 1 1), [Formula: see text]-(Tl, Pb) and [Formula: see text]-(Tl, Pb), have been found and their composition, atomic arrangement and electron properties has been characterized. The (Tl, Pb)/Ge(1 1 1)[Formula: see text] compound is almost identical to the alike (Tl, Pb)/Si(1 1 1)[Formula: see text] system from the viewpoint of its atomic structure and electronic properties. They contain 1.0 ML of Tl atoms arranged into a honeycomb network of chained trimers and 1/3 ML of Pb atoms occupying the centers of the honeycomb units. The (Tl, Pb)/Ge(1 1 1)[Formula: see text] compound contains six Tl atoms and seven Pb atoms per [Formula: see text] unit cell (i.e. ∼0.67 ML Tl and ∼0.78 ML Pb). Its atomic structure can be visualized as consisting of Pb hexagons surrounded by Tl trimers. The (Tl, Pb)/Ge(1 1 1)[Formula: see text] and (Tl, Pb)/Ge(1 1 1)[Formula: see text] compounds are metallic and their band structures contain spin-split surface-state bands. By analogy with the (Tl, Pb)/Si(1 1 1)[Formula: see text], these (Tl, Pb)/Ge(1 1 1) compounds are believed to be promising objects for prospective studies of superconductivity in one-atom-layer systems.

Two-Dimensional Superconductor with a Giant Rashba Effect: One-Atom-Layer Tl-Pb Compound on Si(111).

A one-atom-layer compound made of one monolayer of Tl and one-third monolayer of Pb on a Si(111) surface having √3×√3 periodicity was found to exhibit a giant Rashba-type spin splitting of metallic surface-state bands together with two-dimensional superconducting transport properties. Temperature-dependent angle-resolved photoelectron spectroscopy revealed an enhanced electron-phonon coupling for one of the spin-split bands. In situ micro-four-point-probe conductivity measurements with and without magnetic field demonstrated that the (Tl, Pb)/Si(111) system transformed into the superconducting state at 2.25 K, followed by the Berezinskii-Kosterlitz-Thouless mechanism. The 2D Tl-Pb compound on Si(111) is believed to be the prototypical object for prospective studies of intriguing properties of the superconducting 2D system with lifted spin degeneracy, bearing in mind that its composition, atomic and electron band structures, and spin texture are already well established.

Incommensurate superstructure in heavily doped fullerene layer on Bi/Si(111) surface.

Cs adsorption onto the C60-covered Si(111)-ß-√3×√3-Bi reconstruction has been studied by means of scanning tunneling microscopy and photoelectron spectroscopy. Unexpected increase in apparent size of every second C60 molecule has been detected, hereupon the close packed molecular array almost doubles its periodicity. The change affects only the fullerenes that are in direct contact with the metal-induced reconstruction and takes no place already in the second layer. Photoelectron studies have revealed that this incommensurate "2 × 2" superstructure of a heavily doped C60 monolayer remains in an insulating state regardless of doping level.

[Dynamics of daily rhythm changes of arterial blood pressure in hypopinealism].

The article presents the original data on the character of the changes in arterial blood pressure (ABP) in rabbit with hypopinealism induced by long 24-hour lighting. In experimental animals registered leveling the daily rhythm of ABP primarily because of increase this value in dark time (night, evening) and formation of arterial hypertension by 'non-dipper".

[POLYMORPHISM OF ALFA-AMYLASE AND CONJUGATION IN COMMON WHEAT ENZYME TYPES WITH QUANTITATIVE TRAITS OF PLANTS].

Using polymorphism of alpha-amylase in the winter common wheat studied inheritance isoenzymes and its conjugation enzyme types with germinating grain on the "vine", grain productivity, plant height and time of ear formation. It is shown that the polymorphism isoenzyme of alpha-amylase wheat is limited by the presence of different loci whose products are similar in electrophoretic parameters. In this regard, one component of the enzyme can be controlling at one or two or three genes. Identification of a locus controlling alpha-amylase isoenzyme in the fast moving part of the electrophoretogram, designated as α-Amy-B7. Determine the distance of the locus to factor α-Amy-B6.

Effect of Na adsorption on the structural and electronic properties of Si(111)√3 × âˆš3-Au surface.

Adsorption of ∼0.1 ML of Na onto the Si(111)√3 × âˆš3-Au surface held at 300 °C has been found to induce pronounced changes in its structural and electronic properties. Domain wall networks, characteristic of the pristine surface, are removed completely, leading to the formation of a highly ordered homogeneous surface. The original atomic arrangement of the Si(111)√3 × âˆš3-Au is preserved and Na atoms occupy T4 adsorption sites at the centers of surface Si trimers. Upon Na adsorption, a pronounced metallic S1 surface-state band develops. It is characterized by a large spin splitting (momentum splitting at the Fermi level Δk∥ = 0.027 Å(-1) and consequent energy splitting ΔEF = 110 meV), large electron filling (on the order of 0.5 electrons per √3 × âˆš3 unit cell) and small effective electron mass of (0.028 ± 0.006)me. The natural consequence of the latter properties is a high surface conductivity of the Si(111)√3 × âˆš3-(Au, Na) surface.

[Role of the change of daily rhythms of adrenaline and noradrenaline concentration in blood in the mechanism of accelerated aging in hypopinealizm induced by a long period of day and night lighting].

In young adult male rabbits circadian rhythms change of blood concentrations of adrenaline and noradrenaline in the dynamics of hypopinealism development induced by a long period (5 months) twenty-four-hour lighting of low intensity (30-40 lux) were studied. It was found that the light in the night leads to a significant increase in the levels of both catecholamines, which indicates on the activation of the sympathoadrenal system (SAS), just as it occurs in aging and stress (stress-age-syndrome by V.V. Frolkis). Daily features of SAS reactions to light stress were revealed. Based on these data it can be concluded that one of the reduction mechanisms of life expectancy at hypopinealizm is excessive and prolonged activation of SAS.

[Use of the common winter wheat homozygous population for genetic analysis of beta-amylase and evaluation of its aggregation ability].

We investigated a self-pollinated homozygous population of common winter wheat, F(-> ∞) 24/04 x Odesskaya krasnokolosaya, for variants of beta-amylase and the aggregation ability of the protein complex of weevil via disulfide bonds. It was found that variation in the electrophoretic types of this enzyme was due to four isoenzymes. Two of them (a and b) are doubled and controlled by separate loci with independent inheritance. Isoenzyme c was due to three dominant factors, and four loci were responsible for d. Analysis of the number of -S-S-bonds of five genotypes, which were harvested in 2013 and differed in the types of beta-amylase, showed that some of them were significantly different from others in this indicator. In general, the samples were grouped by the type of this enzyme, forming the following continuous series with respect to aggregation ability: I ≥ B ≥ F ≥ D ≥ G or 59.13 ± 3.18 ≥ 56.65 ± 2.46 ≥ 52.54 ± 2.24 ≥ 50.16 ± 1.67 ≥ 48.63 ± 6.25 of cond. units. Significant differences were observed for this property between groups B > D and I > D. Therefore, genotypes having types I and B have a positive influence on the rheological properties of dough.

Structural transformations in Pb/Si(111) phases induced by C60 adsorption.

Structural transformations at the Pb/Si(111) surface occurring upon C60 adsorption onto Pb/Si(111)1 × 1 phase at room temperature and Pb/Si(111)[Formula: see text] at low temperatures between 30 and 210 K, have been studied using scanning tunneling microscopy and low-energy electron diffraction observations. Typically, C60 fullerenes agglomerate into random molecular islands nucleated at the surface defects. C60 island formation is accompanied by expelling Pb atoms to the surrounding surface area where more dense Pb/Si(111) phases form. Productivity of C60-induced expelling of Pb atoms is controlled by surface defects and is suppressed dramatically when regular ('crystalline') C60 islands self-assemble at the defect-free Pb/Si(111) surface. When Pb atoms are ejected by the random C60 islands, extended structural transformations involving reordering of numerous Pb atoms are fully completed at the surface within the shortest possible time (a few dozen seconds) to reapproach and image the surface after C60 deposition. Estimations show that the observed transformations cannot be controlled by random walk diffusion of Pb adatoms, which implies a highly correlated motion of the Pb atom displacements within the layer.

Large spin splitting of metallic surface-state bands at adsorbate-modified gold/silicon surfaces.

Finding appropriate systems with a large spin splitting of metallic surface-state band which can be fabricated on silicon using routine technique is an essential step in combining Rashba-effect based spintronics with silicon technology. We have found that originally poor structural and electronic properties of the Au/Si(111) √3 x √3 surface can be substantially improved by adsorbing small amounts of suitable species (e.g., Tl, In, Na, Cs). The resultant surfaces exhibit a highly-ordered atomic structure and spin-split metallic surface-state band with a momentum splitting of up to 0.052 Å(-1) and an energy splitting of up to 190 meV at the Fermi level. The family of adsorbate-modified Au/Si(111) √3 x √3 surfaces, on the one hand, is thought to be a fascinating playground for exploring spin-splitting effects in the metal monolayers on a semiconductor and, on the other hand, expands greatly the list of material systems prospective for spintronics applications.

Stepwise self-assembly of C60 mediated by atomic scale moiré magnifiers.

Self-assembly of atoms or molecules on a crystal surface is considered one of the most promising methods to create molecular devices. Here we report a stepwise self-assembly of C60 molecules into islands with unusual shapes and preferred sizes on a gold-indium-covered Si(111) surface. Specifically, 19-mer islands prefer a non-compact boomerang shape, whereas hexagonal 37-mer islands exhibit extraordinarily enhanced stability and abundance. The stepwise self-assembly is mediated by the moiré interference between an island with its underlying lattice, which essentially maps out the adsorption-energy landscape of a C60 on different positions of the surface with a lateral magnification factor and dictates the probability for the subsequent attachment of C60 to an island's periphery. Our discovery suggests a new method for exploiting the moiré interference to dynamically assist the self-assembly of particles and provides an unexplored tactic of engineering atomic scale moiré magnifiers to facilitate the growth of monodispersed mesoscopic structures.

[Genetic control of several alpha-amylase isozymes in winter hexaploid wheat].

alpha-Amylase isozymes were detected via electrophoretic separation in a Tris-glycine polyacrylamide gel system (pH 8.4). Three chromosome 6B loci controlling the alpha-amylase isozyme composition were identified by studying the grain alpha-amylase patterns in an F --> infinity self-pollinating population of winter common wheat (Donskoi Mayak). The loci were found to take the following order in the long arm of chromosome 6B: cen.-alpha-Amy-B3-alpha-Amy-B6-alpha-Amy-B1-.

[The ß-amylase polymorphism of winter common wheat grains].

The polymorphism of winter common wheat with respect to ß-amylase isoenzymes has been analyzed using electrophoresis in polyacrylamide gel (PAAG) buffered with a Tris-glycine system (pH 8.3). Seven ß-amylase isoenzymes have been found in wheat cultivars and the breeding stock. Isoenzymes A, B, and C are the most frequent in Russian and Ukrainian cultivars (51.7 4.7, 30.7 3.8, and 11.9 2.5%, respectively). Two alleles of the ß-Amy-D1 locus of the long arm of chromosome 4D have been identified. The substrate-enzyme affine effect can be used to locate the zones of activity of this enzyme by means of staining for proteins. It has been determined that ß-amylase zymotypes may play a role in the aggregating capacity of the grain protein complex via the formation of S-S bonds.

Intensity of in vitro incorporation of 3H-melatonin in the thyroid gland of rabbits with pineal gland hypofunction.

The structure and hormonal activity of the thyroid gland and its capacity to bind (3)H-melatonin were studied in young adult Chinchilla rabbits with pineal gland hypofunction induced by 2-month exposure to constant illumination. After 2 months of constant exposure to light, the experimental animals exhibited signs of the so-called "latent hypothyroidism" and more intense binding of (3)H-melatonin by the thyroid gland. This fact indicated intactness of its receptor system underlying the possibility of restoring activity of the thyroid gland under conditions of melatonin replacement therapy in hypothyroidism induced by chronic melatonin insufficiency.