A Comparative Study of Biocathodes Based on Multiwall Carbon Nanotube Buckypapers Modified with Three Different Multicopper Oxidases

14 Single‐ and multi‐walled carbon nanotubes from different sources were characterized in detail, and the characteristics obtained were carefully analyzed. The carbon material with the highest capacitance, and also other superior properties (“Taunit‐M” from “NanoTechCenter”, Russia), was chosen for further modification and fabrication of buckypaper based electrodes. These electrodes were biomodified with plant and fungal laccases, as well as fungal bilirubin oxidase. The designed biocathodes were investigated in simple buffers and also in a complex physiological fluid (human serum). Biocathodes based on immobilized fungal laccase were bioelectrocatalytically inactive in chloride containing media at neutral pH. In spite of the quite high current densities realized using biodevices based on plant laccase and fungal bilirubin oxidase, the limited thermal stability of the enzymes renders the biocathodes inadequate for practical applications in implanted situations.     

The dynamic discrepancy method for a differential equation with memory

We study the problem of recovering a control for a system of parabolic type with memory. We exhibit a finite-step algorithm for solving the problem, based on the discrepancy method. The algorithm is resistant to informational noise and computational errors. Bibliography: 22 titles. Translated fromProblemy Matematicheskoi Fiziki, 1998, pp. 68–74.     

Reaction of 3,3,3-trifluoropropene-1 with bromoform and methylene bromide

The radical telomerization of 3,3,3-trifluoropropene with bromoform and methylens bromide has been studied. The nature of the products with bromoform depends substantially on the method of initiation. In the presence of Fe(CO)₅ + DMF, telomers of CHBr₂(CH₅₂CHCF₃)_nBr are formed, while with initiation with benzoyl peroxide other compounds are also formed that contain two, three, or four bromine atoms per molecule. To elucidate the formation of these products a reaction scheme is proposed that involves rearrangement of CHBr₂CH₂CH(CF₃)CH₃CHCF₃ radicals to CBr₂CH₂CH(CF₃)CH₂CH₂CF₃ radicals.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2558–2562, November, 1989.     

Optimization of Natural Water Purification to Remove Nickel and Copper Ions with Carbonate Flour

The reaction of nickel(II) and copper(II) sulfate solutions with carbonate flour prepared from carbonatite was simulated thermodynamically and studied experimentally. The conditions under which open systems and those isolated from the atmosphere attain stationary state (carbonatite consumption and grain size, pH of the medium) were determined. The ionic and mineral composition of new formations and the theoretically possible degree of purification were found.     

Porous Hydrophobized Electrode Operation in Indirect Electrosynthesis Involving a Fast Chemical Reaction

Russian Journal of Electrochemistry -     

Lower Bounds for the Rate of Convergence of Dynamic Reconstruction Algorithms for Distributed-Parameter Systems

We obtain lower bounds for the rate of convergence of reconstruction algorithms for distributed-parameter systems of parabolic type. In the case of a pointwise constraint on control for known reconstruction algorithms, we establish a lower bound on the rate of convergence, which shows that, given certain conditions, for each solution of the system one can choose such a collection of measurements so that the reconstruction error will not be less than a certain value. In the case of unbounded controls, we obtain lower bounds for a possible reconstruction error for each trajectory as well as for a given set of trajectories. For a system of special form, we construct an algorithm for which we obtain upper and lower bounds for accuracy having identical order for a specific choice of matching of the parameters.     

Composition and Catalytic Activity of Plasma-Electrolytic Manganese Oxide Films on Titanium,Modified with Silver Compounds

The effect of impregnation in aqueous solutions of AgNO₃ and subsequent calcination of manganese oxide surface structures produced on a titanium substrate by plasma-electrolytic oxidation on their catalytic activity in oxidation of CO was studied.