Surface potential at a ferroelectric grain due to asymmetric screening of depolarization fields

Nonlinear screening of electric depolarization fields, generated by a stripe domain structure in a ferroelectric grain of a polycrystalline material, is studied within a semiconductor model of ferroelectrics. It is shown that the maximum strength of local depolarization fields is rather determined by the electronic band gap than by the spontaneous polarization magnitude. Furthermore, field screening due to electronic band bending and due to presence of intrinsic defects leads to asymmetric space charge regions near the grain boundary, which produce an effective dipole layer at the surface of the grain. This results in the formation of a potential difference between the grain surface and its interior of the order of 1 V, which can be of either sign depending on defect transition levels and concentrations. Exemplary acceptor doping of BaTiO3 is shown to allow tuning of the said surface potential in the region between 0.1 and 1.3 V.Comment: 14 pages, 11 figures, submitted to J. Appl. Phy

Preclinical study of the efficacy and safety of wound healing gel containing chitosan, taurine and allantoin

Objectives: To develop gel containing chitosan, taurine, allantoin, and to experimentally investigate its wound healing properties in preclinical studies on laboratory animal

Comparison of Recombinant Human Haptocorrin Expressed in Human Embryonic Kidney Cells and Native Haptocorrin

Haptocorrin (HC) is a circulating corrinoid binding protein with unclear function. In contrast to transcobalamin, the other transport protein in blood, HC is heavily glycosylated and binds a variety of cobalamin (Cbl) analogues. HC is present not only in blood but also in various secretions like milk, tears and saliva. No recombinant form of HC has been described so far. We report the expression of recombinant human HC (rhHC) in human embryonic kidney cells. We purified the protein with a yield of 6 mg (90 nmol) per litre of cell culture supernatant. The isolated rhHC behaved as native HC concerning its spectral properties and ability to recognize both Cbl and its baseless analogue cobinamide. Similar to native HC isolated from blood, rhHC bound to the asialoglycoprotein receptor only after removal of terminal sialic acid residues by treatment with neuraminidase. Interestingly, rhHC, that compared to native HC contains four excessive amino acids (…LVPR) at the C-terminus, showed subtle changes in the binding kinetics of Cbl, cobinamide and the fluorescent Cbl conjugate CBC. The recombinant protein has properties very similar to native HC and although showing slightly different ligand binding kinetics, rhHC is valuable for further biochemical and structural studies

Formality theorems for Hochschild chains in the Lie algebroid setting

In this paper we prove Lie algebroid versions of Tsygan's formality conjecture for Hochschild chains both in the smooth and holomorphic settings. In the holomorphic setting our result implies a version of Tsygan's formality conjecture for Hochschild chains of the structure sheaf of any complex manifold and in the smooth setting this result allows us to describe quantum traces for an arbitrary Poisson Lie algebroid. The proofs are based on the use of Kontsevich's quasi-isomorphism for Hochschild cochains of R[[y_1,...,y_d]], Shoikhet's quasi-isomorphism for Hochschild chains of R[[y_1,...,y_d]], and Fedosov's resolutions of the natural analogues of Hochschild (co)chain complexes associated with a Lie algebroid.Comment: 40 pages, no figure

STUDY AND SIMULATION OF HEAT TRANSFER PROCESSES DURING FOAM GLASS HIGH TEMPERATURE PROCESSING

The paper presents basic aspects of simulation of pores formation and growth in the foam glass structure process during raw material mixture high temperature processing. The key mathematical approaches to heat transfer processes simulation and the dynamics of the pores radius growth in the raw material mixture structure are presented. The key assumptions and restrictions allowing representing the most adequate research outcomes at this stage of the subject development are outlined

KINETICS OF STRUCTURAL TRANSFORMATIONS AT PORES FORMATION DURING HIGH-TEMPERATURE TREATMENT OF FOAM GLASS

The work shows the key points used in the simulation of pores formation and growth in the foam glass structure. Pore is represented as a separate radius growth center with the outer boundary of a spherical shape and with a specified value of the initial radius surrounded by a finite volume of molten glass that is a part of foam glass charge stock. Solution of three-dimensional problem is reduced to one-dimensional setting in spherical coordinates. The presented model takes into consideration kinetics of pores radius growth, taking into account the influence of glass viscosity and surface tension, as well as the effect of moving (stretching) glass cladding when pores radius increases

Weyl-Underhill-Emmrich quantization and the Stratonovich-Weyl quantizer

Weyl-Underhill-Emmrich (WUE) quantization and its generalization are considered. It is shown that an axiomatic definition of the Stratonovich-Weyl (SW) quantizer leads to severe difficulties. Quantization on the cylinder within the WUE formalism is discussed.Comment: 15+1 pages, no figure

Atmospheric bistatic communication channels with scattering. Part 2. Field Experiments in 2013

Results of field experiments on the influence of atmospheric conditions and some instrumental characteristics on the quality of information transfer in a bistatic optoelectronic communication system (OECS) operating in the visible wavelengths range are considered. The length of the atmospheric channel reached 17 km. Radiation of a copper bromide vapor laser with a wavelength of 510.6 nm was used as a signal source. It is shown that bistatic or over-the-horizon OECSs can operate both under the conditions of a cloudy and cloud-free atmosphere. Average values and standard deviations of communication errors were estimated under different atmospheric-optical conditions when some characteristics of individual instrumentation units varied

Characterization of a monoclonal antibody with specificity for holo-transcobalamin

BACKGROUND: Holotranscobalamin, cobalamin-saturated transcobalamin, is the minor fraction of circulating cobalamin (vitamin B12), which is available for cellular uptake and hence is physiologically relevant. Currently, no method allows simple, direct quantification of holotranscobalamin. We now report on the identification and characterization of a monoclonal antibody with a unique specificity for holotranscobalamin. METHODS: The specificity and affinity of the monoclonal antibodies were determined using surface plasmon resonance and recombinant transcobalamin as well as by immobilizing the antibodies on magnetic microspheres and using native transcobalamin in serum. The epitope of the holotranscobalamin specific antibody was identified using phage display and comparison to a de novo generated three-dimensional model of transcobalamin using the program Rosetta. A direct assay for holotrnscobalamin in the ELISA format was developed using the specific antibody and compared to the commercial assay HoloTC RIA. RESULTS: An antibody exhibiting >100-fold specificity for holotranscobalamin over apotranscobalamin was identified. The affinity but not the specificity varied inversely with ionic strength and pH, indicating importance of electrostatic interactions. The epitope was discontinuous and epitope mapping of the antibody by phage display identified two similar motifs with no direct sequence similarity to transcobalamin. A comparison of the motifs with a de novo generated three-dimensional model of transcobalamin identified two structures in the N-terminal part of transcobalamin that resembled the motif. Using this antibody an ELISA based prototype assay was developed and compared to the only available commercial assay for measuring holotranscobalamin, HoloTC RIA. CONCLUSION: The identified antibody possesses a unique specificity for holotranscobalamin and can be used to develop a direct assay for the quantification of holotranscobalamin

Endothelial dysfunction as a major cardiovascular risk factor limiting the performance of young athletes: assessment and correction with specialized food products based on apian and herbal components

Objective: to assess with exercise tests the endothelial dysfunction (ED) and performance before and after the treatment with specialized athlete’s nutrition product (SANP) with apian and herbal components. Materials and methods: 88 athletes aged 16-18 we tested. The main group included 58 athletes, who took SANP (candy bar «Gold F25 ApiSpeis Light») for 2 months. The control group-1 included 32 schoolchildren and students, non-athletes, with normal endothelium-dependent vasodilatation function of the brachial artery (EDVD BA) at the peak of the reactive hyperemia test (RHT). Control group-2, 30 athletes who did not take SANP, was formed for the comparison with the main group after taking SANP. For all individuals, we evaluated the level of EDVD, endothelium-dependent vasoconstriction (EDVC BA) at the peak of the hyperventilation test (HVT), the coefficients (C) of the endothelial sensitivity to shear stress and the blood flow velocity (Vps) of the BA at the peak of the RHT and HVT, the endothelial sensitivity index (ESI), and the maximum load (Wmax), the anaerobic threshold time (ATT). We also did general and biochemical blood tests. Results: the earliest manifestation of endothelial dysfunction is a decrease in sensitivity to shear stress during RHT and HVT resulting from endotheliocyte overstrain which can be assessed with ESI (sensitivity 80.9%, specificity 99.4 The EDVD diagnostic significance was 5.6 times lower than that of EIS, while 10.5% of athletes with over 10% EDVD actually had ED, with a predominant vasospasm and high cardiovascular risk. After the course of SANP in the main group, EDVD increased by 70%, EDVC decreased by 2.2 times, and the ESI increased by 2.3 times, against the background of improved performance. Total cholesterol decreased by 13%, triglycerides by 17%, cortisol by 14%, lactate by 25%. Red blood cell and mineral levels increased. A correlation was found between an increase in ATT a decrease in cortisol (r=-0.53; p<0.0001), an increase in red blood cells (r=0.62; p<0.0001), and an increase in Vps in BA during of hyperventilation with an increase in Wmax (r=0.52; p<0.0001). Conclusions: ED is the main factor of cardiovascular risk, limiting working capacity and forming a spastic type of regional hemodynamics of young athletes. The ESI criterion enables the detection of a decrease in the endothelial sensitivity to shear stress during a hyperventilation test, which causes the predominant vasospasm. Th e tested SANP can be used in the system of biomedical support for young athletes