Design of Mixed Ionic-Electronic Materials for Permselective Membranes and Solid Oxide Fuel Cells Based on Their Oxygen and Hydrogen Mobility.

Oxygen and hydrogen mobility are among the important characteristics for the operation of solid oxide fuel cells, permselective membranes and many other electrochemical devices. This, along with other characteristics, enables a high-power density in solid oxide fuel cells due to reducing the electrolyte resistance and enabling the electrode processes to not be limited by the electrode-electrolyte-gas phase triple-phase boundary, as well as providing high oxygen or hydrogen permeation fluxes for membranes due to a high ambipolar conductivity. This work focuses on the oxygen and hydrogen diffusion of mixed ionic (oxide ionic or/and protonic)-electronic conducting materials for these devices, and its role in their performance.

Synthesis and Oxygen Mobility of Bismuth Cerates and Titanates with Pyrochlore Structure.

Synthesis and study of materials based on bismuth cerates and titanates were carried out. Complex oxides BiYTiO were synthesized by the citrate route; BiCeO and BiYCeO-by the Pechini method. The structural characteristics of materials after conventional sintering at 500-1300 °C were studied.

Approaches to the design of efficient and stable catalysts for biofuel reforming into syngas: doping the mesoporous MgAlO support with transition metal cations.

The mesoporous MgAlO support is promising for the design of efficient and stable to coking catalysts for natural gas and biofuel reforming into syngas. This work aims at doping this support with transition metal cations (Fe, Cr, Ti) to prevent the incorporation of Ni and rare-earth cations (Pr, Ce, Zr), loaded by impregnation, into its lattice along with providing additional sites for CO activation required to prevent coking. Doped MgAlMeO (Me = Fe, Ti, Cr) mesoporous supports prepared by the one-pot evaporation-induced self-assembly method with Pluronic P123 triblock copolymers were single-phase spinels.

Dry Reforming of Methane over 5%Ni/CeTiO Catalysts Obtained via Synthesis in Supercritical Isopropanol.

A series of 5%Ni/CeTiO catalysts was prepared with nickel impregnation of mixed Ce-Ti oxides obtained via synthesis in supercritical isopropanol. All oxides have a cubic fluorite phase structure. Ti is incorporated into the fluorite structure.

Carbon Formation during Methane Dry Reforming over Ni-Containing Ceria-Zirconia Catalysts.

Two series of Ni/Ce(Ti/Nb)ZrO catalysts were prepared using citrate route and original solvothermal continuous flow synthesis in supercritical isopropanol and studied in dry reforming of methane (DRM). TEM, XPS and FTIRS of adsorbed CO confirm influence of support composition and preparation method on the catalysts' morphology and surface features. The oxygen mobility was studied by isotope heteroexchange with CO.

Structural and Transport Properties of E-Beam Sintered Lanthanide Tungstates and Tungstates-Molybdates.

Lanthanide tungstates and molybdates are promising materials for hydrogen separation membranes due to their high protonic conductivity. A promising approach to fabricating ceramics based on these materials is radiation thermal sintering. The current work aims at studying the effect of radiation thermal sintering on the structural morphological and transport properties of (Nd,Ln)(W,Mo)O as promising materials for hydrogen separation membranes.

Model-Based Performance Analysis of Membrane Reactor with Ethanol Steam Reforming over a Monolith.

Membrane reactors (MR) with an appropriate catalyst are considered to be an innovative and intensified technology for converting a fuel into the hydrogen-rich gas with the simultaneous recovery of high-quality hydrogen. Characteristics of an asymmetric membrane disk module consisting of a gas-tight nanocomposite functional coating (Ni + Cu/NdWO mixed proton-electron conducting nanocomposite) deposited on a gas-permeable functionally graded substrate has previously been extensively studied at lab-scale using MRs, containing the catalyst in a packed bed and in the form of a monolith. The catalytic monolith consisted of a FeCrAl substrate with a washcoat and an Ni + Ru/PrCeZrO active component.

Structural and transport properties of Nd tungstates and their composites with NiCuO obtained by mechanical activation.

Nd tungstates and molybdates are promising materials for hydrogen separation membranes due to their high protonic conductivity. This work aims at elucidating the structural, textural and oxygen transport features of NdWO, NdWMoO and (NdLa)WO and their composites with NiCuO synthesized by mechanical activation. The oxide materials obtained were distorted double fluorites but their composites with NiCuO possess a complex phase composition.

An Experimental Performance Study of a Catalytic Membrane Reactor for Ethanol Steam Reforming over a Metal Honeycomb Catalyst.

The present study deals with the combination of ethanol steam reforming over a monolithic catalyst and hydrogen separation by membrane in a lab-scale catalytic membrane reactor (CMR). The catalyst was comprised of honeycomb thin-walled Fechralloy substrate loaded with Ni + Ru/PrCeZrO active component. The asymmetric supported membrane consisted of a thin Ni-Cu alloy-Nd tungstate nanocomposite dense permselective layer deposited on a hierarchically structured asymmetric support.

Effect of Asymmetric Membrane Structure on Hydrogen Transport Resistance and Performance of a Catalytic Membrane Reactor for Ethanol Steam Reforming.

The performance of catalytic membrane reactors (CMRs) depends on the specific details of interactions at different levels between catalytic and separation parts. A clear understanding of decisive factors affecting their operational parameters can be provided via mathematical simulations. In the present paper, main results of numerical studies of ethanol steam reforming, followed by downstream hydrogen permeation through an asymmetric supported membrane, are reported.

Superoxide Dismutase 1 Nanoparticles (Nano-SOD1) as a Potential Drug for the Treatment of Inflammatory Eye Diseases.

Inflammatory eye diseases remain the most common clinical problem in ophthalmology. The secondary processes associated with inflammation, such as overproduction of reactive oxygen species (ROS) and exhaustion of the endogenous antioxidant system, frequently lead to tissue degeneration, vision blurring, and even blindness. Antioxidant enzymes, such as copper-zinc superoxide dismutase (SOD1), could serve as potent scavengers of ROS.

Covalently immobilized chemically modified lysozyme as a sorbent for bacterial endotoxins (lipopolysaccharides).

Chemical modification of lysozyme was carried out using benzaldehyde and anisaldehyde. It was shown that chemical modification affects only 1-2 amino groups of the protein molecule which does not prevent further covalent immobilization of lysozyme using the remaining free amino groups. The bacteriolytic activity of lysozyme is preserved after chemical modification and after subsequent covalent immobilization.

New Sorbent on the Basis of Covalently Immobilized Lysozyme for Removal of Bacterial Lipopolysaccharide (Endotoxin) from Biological Fluids.

It was demonstrated for the first time that immobilized lysozyme can efficiently remove Escherichia coli and Pseudomonas aeruginosa lipopolysaccharides (endotoxins) from solutions. Experimentally confirmed sorption capacity for the developed sorbent was at least 400 ng of endotoxin per ml sorbent. The new sorbent is compatible with the whole human blood and can be potentially used in extracorporeal therapy in the treatment of sepsis.

Comparative Study of Electrical Conduction and Oxygen Diffusion in the Rhombohedral and Bixbyite LnMoO (Ln = Er, Tm, Yb) Polymorphs.

Electrical conduction and oxygen diffusion mobility in the bixbyite ( Ia3̅) and rhombohedral ( R3̅) polymorphs of the LnMoO (Ln = Er, Tm, Yb; Δ = δ, δ1, δ2; δ1 > δ2) heavy lanthanide molybdates, belonging to new, previously unexplored classes of potential mixed (ionic-electronic) conductors, have been studied in the range of 200-900 °C. The oxygen self-diffusion coefficient in bixbyite ( Ia3̅) YbMoO phase estimated by the temperature-programmed heteroexchange with CO was shown to be much higher than that for rhombohedral ( R3̅) RI (with large oxygen deficiency) and ( R3̅) RII (with small oxygen deficiency) LnMoO (Ln = Tm, Yb; Δ = δ1; δ1 > δ2) oxides. According to the activation energy for total conduction in ambient air, 0.

The bacteriolytic activity of native and covalently immobilized lysozyme against Gram-positive and Gram-negative bacteria is differentially affected by charged amino acids and glycine.

The emergence of new antibiotic-resistant bacterial strains means it is increasingly important to find alternatives to traditional antibiotics, such as bacteriolytic enzymes. The bacteriolytic enzyme lysozyme is widely used in medicine as an antimicrobial agent, and covalent immobilization of lysozyme can expand its range of possible applications. However, information on the effect of such immobilized preparations on whole bacterial cells is quite limited.

Proton and oxygen ion conductivity in the pyrochlore/fluorite family of LnCaScMO (Ln = La, Sm, Ho, Yb; M = Nb, Ta; x = 0, 0.05, 0.1) niobates and tantalates.

The tolerance factor is a good criterion to understand the structural transitions in LnCaScMO (Ln = La, Sm, Ho, Yb; M = Nb, Ta; x = 0, 0.05, 0.1).

[The study of protease primary specificity by statistical analysis of MALDI mass-spectra of proteolysis products].

Experimental verification for studying of proteolytic enzymes' primary specificity by statistical analysis of MALDI (matrix-assisted laser desorption/ionization) mass spectra of products obtained by protein substrates proteolysis was done by the use of proteinases with known substrate specificity (trypsin and glutamylendopeptidase). Proposed technique not requires direct determination of proteolysis products amino acid sequences, reliably establishes proteinases with anarrow substrate specificity and shows a relative tolerance for the presence in MALDI mass-spectra peaks of contaminants. It was shown that the pseudo-positive results exception requires the use of protein substrates series with the following averaging received statistical data.

[Theoretical possibilities and limitations of protease primary specificity determination by statistical analysis of MALDI mass-spectra of proteolysis products].

Possibilities and limitations of method examination of proteolytic enzymes' primary specificity by statistical analysis of MALDI (matrix-assisted laser desorption/ionization) mass spectra of products obtained by protein substrates proteolysis without direct determination of their amino acid sequences were investigated theoretically. The optimum ranges given by the errors of the peptides masses measuring for the fabrication of statistical set of the events and the form of statistical data presentation were chosen. It was shown that the proposed method can be applied only for proteases with a relatively narrow primary specificity (two or three amino acids).

[Enzymatic hydrolysis of keratin-containing stock for obtaining protein hydrolysates].

Optimization of the process of enzymatic hydrolysis of keratin-containing stock aimed at obtaining hydrolysates of high biological value has been performed. The increasing of the stock/water weight ratio, the amount of the alkaline protease preparation from Acremonium chrysogenium added and the temperature of the reaction mixture resulted in an increase in the yield and antioxidant capacity of hydrolysis products. The molecular masses of soluble products obtained under optimal hydrolysis conditions ranged from 3.

[A mass-spectrometric approach to primary screening of collagenolytic enzymes].

A comparative analysis of MALDI TOF mass spectra of low-molecular products resulting from the hydrolysis of native collagen I by collagenases of various classes (bacterial metallocollagenase from Clostridium histolyticum, serine collagenase from the Morikrasa commercial preparation, cysteine collagenase from Serratia proteomaculans, and cysteine collagenases from larvae of beetles Dermestesfrischi and D. maculates) was carried out. The spectra contain a number of ion peaks common for all collagenases; nevertheless, the mass spectra of each hydrolysate contains a unique set of peaks ("fingerprint") characteristic of each enzyme.

[Interaction of alpha-chymotrypsin with dimethylsulfoxide: a change of substrate could change the mechanism of interaction].

The kinetic behavior of alpha-chymotrypsin was studied in water-DMSO mixtures at concentrations of the organic solvent that do not cause irreversible denaturation of the enzyme. Various substrates (N-substituted derivatives of L-tyrosine) were found to display substantially different kinetic patterns of interaction with alpha-chymotrypsin, which can be described by totally different kinetic schemes. The differences were ascribed to competition between the N-acyl group of the substrate and the DMSO molecule at the S2-site of substrate binding to the active site of the enzyme.

On the mechanism of interaction of organic solvents with the active site of alpha-chymotrypsin.

Kinetic behavior of alpha-chymotrypsinin the reaction of hydrolysis of the N-acetyl-L-tyrosine derivatives was investigated in non-denaturing water-dimethylsulfoxide and water-ethanol mixtures. Similar specific interactions between the two solvents and the active site of alpha-chymotrypsin were shown to result in similar kinetic effects. It is proposed that the changes in the active site structure of the enzyme caused by the interaction with the organic solvents ("conformational isomer" formation) resulted in two parallel processes--acceleration of the acyl-enzyme formation step and a decrease in the deacylation rate.

Effect of thermosensitive matrix-phase transition on urease-catalyzed urea hydrolysis.

Temperature dependencies of kinetic and equilibrium parameters of urea hydrolysis catalyzed by native urease and the urease immobilized in a thermosensitive poly-N-isopropylacrylamide gel have been studied. The swelling ratio of the collapsed urease-containing gel is shown to increase in the presence of urea. Below a lower critical solution temperature (LCST) of the polymer, the immobilized urease actually has the same catalytic properties as the native enzyme.

[Phase transition in the matrix as a regulator of enzymatic activity of proteinases].

The kinetic behavior of proteolytic enzymes immobilized in thermosensitive hydrogels was studied at the phase transition (collapse) of the carriers. The dependence of the activity of immobilized enzymes on the state of the matrix allows the use of the hydrogel phase transition to regulate the activity of immobilized enzymes. Several cases of such regulation were demonstrated.

Enzyme-dependent responses of stimuli-sensitive systems.

The methods of creating of systems where properties depend both on an outer physical signal and enzyme activity are discussed. The construction of a conjugation chain between responses of stimuli-sensitive materials and urea hydrolysis catalyzed with urease is demonstrated on the basis of light- and thermoreversible polymeric matrices.