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1.
Vestn Otorinolaringol ; 88(6): 56-60, 2023.
Article in Russian | MEDLINE | ID: mdl-38153894

ABSTRACT

OBJECTIVE: To study the features of clinical and laboratory parameters of rhinogenic complications of the orbit (RCO) and eyelids depending on the blood leukocyte shift index (LSI) to create a predictive model in pediatric patients. MATERIAL AND METHODS: The study included 50 patients who were treated at the Regional Clinical Hospital No. 2 of Tyumen with inflammatory pathology of the paranasal sinuses. Group I with RCO - reactive edema of the eyelids and orbital tissue included 29 (58.0%) patients (of which 16 (32.0%) were boys, 13 (26.0%) were girls). In group 2 with ROC, purulent-septic complications of the eyelids and orbit included 21 (42.0%) patients (of which 10 (20.0%) were boys, 11 (22.0%) were girls). RESULTS: LSI values in the general age group (n=50) from 1 to 17 years old were: 1.61 [1.40; 1.82] in patients of group 1; 3.45 [2.96; 3.94] in patients of group 2 (p≤0.05). With an index of LSI from 1.36 to 1.96, the development of reactive edema of the eyelids and orbital tissue is predicted, from 3.14 to 4.72 - the development of purulent-septic complications of the eyelids and orbit in patients of preschool and primary school age. CONCLUSION: The marker of clinical and laboratory parameters of the severity of the disease is the LSI indicator, taking into account the age of the child, which can be used in the early diagnosis of purulent-septic rhinogenic complications of the orbit and eyelids in children.


Subject(s)
Exophthalmos , Paranasal Sinuses , Male , Child, Preschool , Female , Humans , Child , Infant , Adolescent , Orbit , Eyelids , Edema/diagnosis , Edema/etiology
2.
Phys Rev Lett ; 130(7): 076203, 2023 Feb 17.
Article in English | MEDLINE | ID: mdl-36867809

ABSTRACT

The long theorized two-dimensional allotrope of SiC has remained elusive amid the exploration of graphenelike honeycomb structured monolayers. It is anticipated to possess a large direct band gap (2.5 eV), ambient stability, and chemical versatility. While sp^{2} bonding between silicon and carbon is energetically favorable, only disordered nanoflakes have been reported to date. Here we demonstrate large-area, bottom-up synthesis of monocrystalline, epitaxial monolayer honeycomb SiC atop ultrathin transition metal carbide films on SiC substrates. We find the 2D phase of SiC to be almost planar and stable at high temperatures, up to 1200 °C in vacuum. Interactions between the 2D-SiC and the transition metal carbide surface result in a Dirac-like feature in the electronic band structure, which in the case of a TaC substrate is strongly spin-split. Our findings represent the first step towards routine and tailored synthesis of 2D-SiC monolayers, and this novel heteroepitaxial system may find diverse applications ranging from photovoltaics to topological superconductivity.

3.
ACS Appl Mater Interfaces ; 12(38): 43065-43072, 2020 Sep 23.
Article in English | MEDLINE | ID: mdl-32865383

ABSTRACT

Graphene was shown to reveal intriguing properties of its relativistic two-dimensional electron gas; however, its implementation to microelectronic applications is missing to date. In this work, we present a comprehensive study of epitaxial graphene on technologically relevant and in a standard CMOS process achievable Ge(100) epilayers grown on Si(100) substrates. Crystalline graphene monolayer structures were grown by means of chemical vapor deposition (CVD). Using angle-resolved photoemission spectroscopy and in situ surface transport measurements, we demonstrate their metallic character both in momentum and real space. Despite numerous crystalline imperfections, e.g., grain boundaries and strong corrugation, as compared to epitaxial graphene on SiC(0001), charge carrier mobilities of 1 × 104 cm2/Vs were obtained at room temperature, which is a result of the quasi-charge neutrality within the graphene monolayers on germanium and not dependent on the presence of an interface oxide. The interface roughness due to the facet structure of the Ge(100) epilayer, formed during the CVD growth of graphene, can be reduced via subsequent in situ annealing up to 850 °C coming along with an increase in the mobility by 30%. The formation of a Ge(100)-(2 × 1) structure demonstrates the weak interaction and effective delamination of graphene from the Ge/Si(100) substrate.

4.
Phys Rev Lett ; 121(25): 256403, 2018 Dec 21.
Article in English | MEDLINE | ID: mdl-30608778

ABSTRACT

Emergent order at mesoscopic length scales in condensed matter can provide fundamental insight into the underlying competing interactions and their relationship with the order parameter. Using spectromicroscopy, we show that mesoscopic stripe order near the metal-insulator transition (MIT) of strained VO_{2} represents periodic modulations in both crystal symmetry and V-V dimerization. Above the MIT, we unexpectedly find the long-range order of V-V dimer strength and crystal symmetry become dissociated beyond ≈200 nm, whereas the conductivity transition proceeds homogeneously in a narrow temperature range.

5.
Ultramicroscopy ; 183: 49-54, 2017 Dec.
Article in English | MEDLINE | ID: mdl-28527595

ABSTRACT

The Sn intercalation into a buffer layer graphene grown on 4H-SiC(0001) substrate has been studied with spectroscopic photoemission and low energy electron microscope. Both SnSix and SnOx interfacial layers are found to form below the buffer layer, converting it into a quasi-free-standing monolayer graphene. Combining the various operation modes of the microscope allows a detailed insight into the formation processes of the interlayers and their thermal stability. In particular, at the interface we observed a reversible transition from silicide to oxide after exposure to ambient pressure and subsequent annealing. This metal-dielectric transition might be useful for interface engineering in graphene-based devices.

6.
Phys Rev Lett ; 113(21): 216402, 2014 Nov 21.
Article in English | MEDLINE | ID: mdl-25479508

ABSTRACT

We report the simultaneous measurement of the structural and electronic components of the metal-insulator transition (MIT) of VO2 using electron and photoelectron spectroscopies and microscopies. We show that these evolve over different temperature scales, and are separated by an unusual monocliniclike metallic phase. Our results provide conclusive evidence that the new monocliniclike metallic phase, recently identified in high-pressure and nonequilibrium measurements, is accessible in the thermodynamic transition at ambient pressure, and we discuss the implications of these observations on the nature of the MIT in VO2.

8.
Phys Rev Lett ; 109(2): 026101, 2012 Jul 13.
Article in English | MEDLINE | ID: mdl-23030182

ABSTRACT

A very rich Fe-C phase diagram makes the formation of graphene on iron surfaces a challenging task. Here we demonstrate that the growth of graphene on epitaxial iron films can be realized by chemical vapor deposition at relatively low temperatures, and that the formation of carbides can be avoided in excess of the carbon-containing precursors. The resulting graphene monolayer creates a novel periodically corrugated pattern on Fe(110). Using low-energy electron microscopy and scanning tunneling microscopy, we show that it is modulated in one dimension forming long waves with a period of ∼4 nm parallel to the [001] direction of the substrate, with an additional height modulation along the wave crests. The observed topography of the graphene/Fe superstructure is well reproduced by density functional theory calculations, and found to result from a unique combination of the lattice mismatch and strong interfacial interaction, as probed by core-level photoemission and x-ray absorption spectroscopy.

9.
Nanotechnology ; 23(12): 125703, 2012 Mar 30.
Article in English | MEDLINE | ID: mdl-22397834

ABSTRACT

Mirror electron microscopy (MEM) imaging of InAs nanowires is a non-destructive electron microscopy technique where the electrons are reflected via an applied electric field before they reach the specimen surface. However strong caustic features are observed that can be non-intuitive and difficult to relate to nanowire geometry and composition. Utilizing caustic imaging theory we can understand and interpret MEM image contrast, relating caustic image features to the properties and parameters of the nanowire. This is applied to obtain quantitative information, including the nanowire width via a through-focus series of MEM images.

10.
Langmuir ; 28(3): 1775-81, 2012 Jan 24.
Article in English | MEDLINE | ID: mdl-22185488

ABSTRACT

We report on a new nanopatterned structure represented by a single atomic layer of hexagonal boron nitride (h-BN) forming long periodic waves on the Fe(110) surface. The growth process and the structure of this system are characterized by X-ray absorption (XAS), core-level photoemission spectroscopy (CL PES), low-energy electron microscopy (LEEM), microbeam low-energy electron diffraction (µLEED), and scanning tunneling microscopy (STM). The h-BN monolayer on Fe(110) is periodically corrugated in a wavy fashion with an astonishing degree of long-range order, periodicity of 2.6 nm, and the corrugation amplitude of ∼0.8 Å. The wavy pattern results from a strong chemical bonding between h-BN and Fe in combination with a lattice mismatch in either [111] or [111] direction of the Fe(110) surface. Two primary orientations of h-BN on Fe(110) can be observed corresponding to the possible directions of lattice match between h-BN and Fe(110), with approximately equal area of the boron nitride domains of each orientation.

11.
Zh Obshch Biol ; 72(4): 269-83, 2011.
Article in Russian | MEDLINE | ID: mdl-21954628

ABSTRACT

Ants are provided with a balanced system of reactions either to the original paucity of socia or to their secondary depopulation. This system can be defined as a strategy of population concentration. Both a successful reproduction of workers and queen fertilization are necessary conditions for ant communities' survival and development. Thus, the anthills must be large enough to ensure optimal conditions for reproduction. It is the strategy of population concentration that is directed to an accelerated attainment (or rehabilitation) by a socium of a state of stable development by way of concentrating the existent ant staff in an accessible number of viable nests. This strategy is realized throughout the life of ant communities by way of (a) fusing the starting family cells left by founder females, (b) fusing small anthills during artificial ant migrations, (c) uniting smaller socia or their joining other anthills, (d) reintegrating the secondary anthills (fragmentants) after an exogenous fragmentation of formicaries. Pooling and the attraction of deficient demographic resources from outside form the most efficient and quickest ways of reaching or restoring the threshold density levels. By realizing this strategy, the ants solve their paramount problems of anthill or settlement conservation at any particular time, as well as of providing some prospects for ant existence in the future. These problems are so vital for ant socia that they appear to hold priority over such other characteristics of utmost importance as genetic kinship or even species identity. The priority of social basics over genetic ones is unequivocally supported through mixed formicaries. A necessary condition for the realization of the strategy of population concentration is tolerance of highly developed social systems to the diversity of forms and to deviations from the norm. The use of one and the same mechanism at all stages of the life both of an individual socium and large ant settlements is evidence of the universality of this strategy, as well as of its unconditioned importance to the life of ant communities.


Subject(s)
Ants/physiology , Behavior, Animal/physiology , Animals , Female , Male , Models, Statistical , Population Dynamics , Social Behavior
12.
Tsitologiia ; 52(5): 384-8, 2010.
Article in Russian | MEDLINE | ID: mdl-20586273

ABSTRACT

The formulation of "histone code" theory brings active investigations of the role of histone modifications and other supramolecular factors of DNA condensation in transcription regulation. In this work, we have analyzed the localization of methylated histones on 9, 36 and 79 lysines, hyperacetylated H4 histone, and subunits of cohesion complex DRAD21 relatively of Drosophila melanogaster polytene chromosomes chromatin condensation. We propose the hypotheses of a cascade regulation of transcription activity defined by histone modifications and the adaptive role of sister chromatids cohesion in the transcription of high active and extensive genes.


Subject(s)
Cell Cycle Proteins/metabolism , Chromatids/metabolism , Drosophila Proteins/metabolism , Drosophila melanogaster/metabolism , Histones/metabolism , Animals , Chromosomal Proteins, Non-Histone/analysis , Chromosomal Proteins, Non-Histone/metabolism , Chromosome Mapping , Drosophila melanogaster/genetics , Methylation
13.
Nanotechnology ; 20(32): 325304, 2009 Aug 12.
Article in English | MEDLINE | ID: mdl-19620748

ABSTRACT

Ga diffusion from focused ion beam (FIB) milled grooves has been studied using x-ray photoemission electron microscopy (XPEEM) and mirror electron microscopy (MEM). We analyze the surface chemistry of the FIB structures measuring the Ga presence in the top layers of the milled grooves and morphological defects inside the grooves. The Ga is initially strictly confined to the grooves. However, annealing at temperatures as low as 150 degrees C leads to rapid and significant Ga surface diffusion from the FIB structures. The out-diffused Ga forms a thin layer extending up to several microns laterally in a non-regular pattern. The diffusion is significantly enhanced at small crystallites at the edges of the grooves. We explain the general behavior with an atomic scale model in which interstitial Ga in the milled areas diffuses out and substitutes silanol groups on the surface.

14.
Rev Sci Instrum ; 80(12): 123703, 2009 Dec.
Article in English | MEDLINE | ID: mdl-20059146

ABSTRACT

We report the first experiments carried out on a new imaging setup, which combines the high spatial resolution of a photoemission electron microscope (PEEM) with the temporal resolution of extreme ultraviolet (XUV) attosecond pulse trains. The very short pulses were provided by high-harmonic generation and used to illuminate lithographic structures and Au nanoparticles, which, in turn, were imaged with a PEEM resolving features below 300 nm. We argue that the spatial resolution is limited by the lack of electron energy filtering in this particular demonstration experiment. Problems with extensive space charge effects, which can occur due to the low probe pulse repetition rate and extremely short duration, are solved by reducing peak intensity while maintaining a sufficient average intensity to allow imaging. Finally, a powerful femtosecond infrared (IR) beam was combined with the XUV beam in a pump-probe setup where delays could be varied from subfemtoseconds to picoseconds. The IR pump beam could induce multiphoton electron emission in resonant features on the surface. The interaction between the electrons emitted by the pump and probe pulses could be observed.

15.
Phys Rev Lett ; 103(24): 246804, 2009 Dec 11.
Article in English | MEDLINE | ID: mdl-20366220

ABSTRACT

Quasi-free-standing epitaxial graphene is obtained on SiC(0001) by hydrogen intercalation. The hydrogen moves between the (6 square root(3) x 6 square root(3))R30 degrees reconstructed initial carbon layer and the SiC substrate. The topmost Si atoms which for epitaxial graphene are covalently bound to this buffer layer, are now saturated by hydrogen bonds. The buffer layer is turned into a quasi-free-standing graphene monolayer with its typical linear pi bands. Similarly, epitaxial monolayer graphene turns into a decoupled bilayer. The intercalation is stable in air and can be reversed by annealing to around 900 degrees C.

16.
Genetika ; 39(9): 1203-11, 2003 Sep.
Article in Russian | MEDLINE | ID: mdl-14582389

ABSTRACT

The distribution of cohesin complex in polytene chromosomes of Drosophila melanogaster was studied. Cohesin is a complicated protein complex which is regulated by the DRAD21 subunit. Using immunostaining for DRAD21p, the cohesins were shown to be preferentially located in the interband regions. This specificity was not characteristic for puffs, where uniform staining was observed. The presence of a few brightly fluorescent regions (five to ten per chromosome arm) enriched with cohesin complexes was shown. Some of these regions had permanent location, and the others, variable location. No antibody binding was detected in the chromocenter. Immunostaining of interphase nuclei of neuroblasts revealed large cohesin formations. On the polytene chromosomes of D. melanogaster, the Drad21 gene was mapped to the chromocentric region (81) of the L arm of chromosome 3.


Subject(s)
Chromosome Mapping , Drosophila melanogaster/genetics , Nuclear Proteins/genetics , Animals , Cell Cycle Proteins , Chromosomal Proteins, Non-Histone , Fungal Proteins , In Situ Hybridization, Fluorescence , Cohesins
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