Two-stage electrochemical synthesis of double molybdenum carbides

A new two-stage synthesis of double molybdenum and nickel carbides and high-activity and stable catalytic coatings of nickel-promoter molybdenum carbides in salt melts is developed. The first stage includes the formation of molybdenum-nickel alloys by an electrolytic method and currentless transfer in chloride melts. The second stage consists in the carbonization of the alloys in a chloride-carbonate melt under various synthesis conditions. The stabilities of the nickel-promoter catalytic systems are studied, and their catalytic activities in the back water-gas shift reaction are determined

Ca(2+)-mediated mitochondrial ROS metabolism augments Wnt/β-catenin pathway activation to facilitate cell differentiation

Emerging evidence suggests that reactive oxygen species (ROS) can stimulate Wnt/{beta}-catenin pathway in a number of cellular processes. However, potential sources of endogenous ROS have not been thoroughly explored. Here, we show that growth factor depletion in human neural progenitor cells induces ROS production in mitochondria. Elevated ROS levels augment activation of Wnt/{beta}-catenin signaling that regulates neural differentiation. We find that growth factor depletion stimulates release of Ca(2+) from the endoplasmic reticulum stores that subsequently accumulates in the mitochondria and triggers ROS production. The inhibition of mitochondrial Ca(2+) uptake with simultaneous growth factor depletion prevents the rise in ROS metabolism. Moreover, low ROS levels block the dissociation of the Wnt effector Dishevelled from Nucleoredoxin. Attenuation of the response amplitudes of pathway effectors delays the onset of Wnt/{beta}-catenin pathway activation and results in markedly impaired neuronal differentiation. Our findings reveal Ca(2+)-mediated ROS metabolic cues that finetune the efficiency of cell differentiation by modulating the extent of the Wnt/{beta}-catenin signaling output

Magnetic information sensing based on magneto-optic plasmonic nanostructure

Magnetized garnet layer is used to detect thin ferromagnetic layers. Incident light changes its polarization when passing through garnet layer due to Faraday effect. External sources of magnetic field impacts this process. We can detect these changes and so understandnature of external sources

Electrophysical properties of meso-porous silicon free standing films modified with palladium

Resistivity and complex impedance voltage dependences for thick mesoporous silicon free layers were studied in this work. The asymmetrical by the sign of applied voltage experimental curves at low frequencies have been obtained. Modification of electrophysical properties due to introduction of palladium particles into the porous matrix is observed. Impedance change regularities during oxidation of the samples have been measured. The explanation of experimental results by asymmetrical distribution of charge carrier traps in the bulk of porous silicon has been suggested. Energy band diagrams and charge transfer mechanisms of these heterostructures are discussed

Detection of thin ferromagnetic layers based on Faraday effect

Optical head with magnetized garnet layer is used to detect presence of thin ferromagnetic layers such as printed text. Mathematical model of the system presented further was created. By varying opaque material, layer thicknesses and air gap between optical head and scanned object optimal configuration of the system was calculated. Incident P-polarized light affected by garnet layer changes its polarization due to Faraday effect. We can detect presence or absence of ferromagnetic after studying changes in polarization of the reflected light. Comparing results with and without influence of the ferromagnetic layers recognition of printed pattern under opaque material is achieved

Deformation of Curved BPS Domain Walls and Supersymmetric Flows on 2d K\"ahler-Ricci Soliton

We consider some aspects of the curved BPS domain walls and their supersymmetric Lorentz invariant vacua of the four dimensional N=1 supergravity coupled to a chiral multiplet. In particular, the scalar manifold can be viewed as a two dimensional K\"ahler-Ricci soliton generating a one-parameter family of K\"ahler manifolds evolved with respect to a real parameter, $\tau$. This implies that all quantities describing the walls and their vacua indeed evolve with respect to $\tau$. Then, the analysis on the eigenvalues of the first order expansion of BPS equations shows that in general the vacua related to the field theory on a curved background do not always exist. In order to verify their existence in the ultraviolet or infrared regions one has to perform the renormalization group analysis. Finally, we discuss in detail a simple model with a linear superpotential and the K\"ahler-Ricci soliton considered as the Rosenau solution.Comment: 19 pages, no figures. Typos corrected. Published versio

ИЗУЧЕНИЕ ВОЗМОЖНОСТИ РЕГУЛЯЦИИ АНГИОГЕНЕЗА IN VITRO С ПОМОЩЬЮ РЕКОМБИНАНТНЫХ ФРАГМЕНТОВ ИНГИБИТОРОВ АНГИОГЕНЕЗА ЭНДОСТАТИНА, ТУМСТАТИНА И PEDF

Neovascular diseases of visual organ such as age-related macular degeneration, retinopathy of prematurity, diabetic retinopathy, thrombosis of central retina vein and its branches, neovascular glaucoma, choroid and retina tumors have the leading positions in the list of ophtalmopatologies that result in blindness and incapacity. The variety of angiostatic medications of applied ophtalmology is scant. The aim of work was to study the possibile approaches to angiogenesis regulation in vitro with the help of recombinant fragments of natural inhibitors of angiogenesis such as endostatin, tumstatin and PEDF (pigment epithelial derived factor), and also their ability to be the base of potentially feasible and pharmacologically active substances. It is determined that endostatin, tumstatin and PEDF, as well as the comparison medication Bevacizumab in vitro have pro- or antiangiogenic influence. The direction of the biological effect depends on the cultivation conditions, peptide concentration in the cultural fluid and stage of angiogenesis. Неоваскулярные заболевания органа зрения, такие как возрастная макулярная дегенерация, ретинопатия недоношенных, диабетическая ретинопатия, тромбозы центральной вены сетчатки и ее ветвей, неоваскулярная глаукома, опухоли хориоидеи и сетчатки, занимают лидирующие позиции в перечне офтальмопатологии, приводящей к слепоте и инвалидизации, а также к социальной и психологической дезадаптации. Арсенал ангиостатических препаратов в практической офтальмологии скуден. Цель настоящей работы заключалась в изучении возможности регуляции ангиогенеза in vitro с помощью рекомбинантных фрагментов природных ингибиторов ангиогенеза эндостатина, тумстатина и PEDF (pigment epithelial derived factor) и применения их в качестве потенциально возможных фармакологически активных субстанций. Установлено, что in vitro эндостатин, тумстатин и PEDF, как и препарат сравнения бевацизумаб, оказывают про- или антиангиогенное действие. Направленность биологического эффекта зависит от условий культивирования, концентрации пептида в культуральной жидкости и этапа ангиогенеза.

DETERMINATION OF OPTIMAL MODES FOR THE PRODUCTION OF MICRO RANGE METAL POWDERS

This paper presents the results of working out the modes of obtaining micro range powders according to the developed method. It is based on the navigation on the material of the vortex plasma flows of heterogeneous plasma and synchronized high-frequency impact on the electrode. The formation of powders is derived from individual particles heated and accelerated using a high-temperature gas jet - plasma. It is obtained in a special original plasma generator by blowing the plasma-forming inert gas into an electric arc resulting between two electrodes. The possibility of obtaining powders of various sizes and chemical composition by this method on the developed technology has been established. The design of the executive equipment that implements the studied generation process of the micro-size range is best suited for steel wires. Experimental studies made it possible to determine the optimal modes for wires of various chemical composition (steel wire, with a diameter of 1.2 mm, OK Autrod 347Si with a diameter of 0.8 mm). Range of parameters and modes of actuating equipment: current of 70-80A; Plasma-forming gas pressure 0.7- 0.8 atm., Wire feed rate 20-40 mm/s, the frequency of ultrasonic oscillations of 50 MHz and 100 MHz. In these conditions, powders are obtained with a dimension of 50-100 μm

Electrode and chemical reactions during electrodeposition of tantalum products in CsCl melt

This work was accomplished in the context of systematic examination of a role played by electrolyte cation composition in electroreduction processes. The electrochemical behaviour of molten salts systems where CsCl was used as solvent for potassium and caesium oxyfluorotantalates was investigated. In particular, the influence of the electrolysis parameters, such as concentration of tantalum species in electrolyte, temperature and current density on the cathodic products phase composition was determined by X-ray diffraction and scanning electron microscopy. Several phases generally crystallized at the cathode simultaneously. Among identified phases were metallic tantalum in cubic ($\alpha$) and tetragonal (β) crystal modifications and TaO. But the most characteristic phases for the melt under study were two isostructural compounds with pyrochlor type crystal lattice CsTa$_{2+z}^5$O$_{5+y}$F$_{1-y}$ and CsTa$_{2+z}^{5- x}$O$_{5+y}$F$_{1-y}$. The former deposited in the form of transparent dielectric crystals and the later – in the form of metal-like conductive ones. This latter compound seems to be synthesized for the first time. The peculiarities of its structure were described. Electrochemical redox processes in melts containing potassium oxyfluorotantalates dissolved in CsCl were studied by cyclic voltammetry. Three discharge peaks were detected on voltammograms in the temperature range 700-850 $^\circ$C. They were associated with the discharge of TaOF$_6^{3-}$ and TaO$_2$F$_4^{3-}$ complexes and alkali metal cations