Photocatalysts for reagentless disinfection on the basis of titanium dioxide films modified by silver nanoparticles

Using the test cultures of Pseudomonas fluorescens and Lactococcus lactis bacteria, photoinduced pathophysiological properties of film titanium dioxide photocatalysts modified by silver nanoparticles are investigated. It is shown that the deposition of silver leads to an increase in the adsorption of microorganisms from the solution and to a rise in the efficiency of photogeneration of hydroxyl radicals and superoxide ions, which provides the attainment of a high level of antimicrobial activity. In particular, the survival rate of P. fluorescens eubacteria under the UV irradiation in contact with the TiO₂/Ag catalyst decreases by a factor of more than 70 compared with irradiation in the absence of the photocatalyst. The developed photocatalysts allow the manifold increase in the efficiency of the disinfection of aqueous media with the use of ultraviolet.     

Operation of a synchronization system in the presence of green pulse noise

It is analytically shown that, under the action of green pulse noise on a synchronization system, the phase-locking effect is retained; however, the width of the phase-locking zone significantly depends on the pulse amplitude, whereas the character of statistics of times of random-pulse occurrences affects only slightly the synchronization process.     

Thermoengineering analysis of feasibility of heating roads by low-potential heat

A relatively simple model of heat transfer in systems intended to heat a roadbed is proposed. A program for calculating temperature fields has been developed. Variant calculations that make possible to assess the effect of various factors on the temperature of the road surface have been performed.     

New polyamide-containing sorbents for one-step isolation of DNA

A composite sorbent modified with fluorinated aromatic polyamide, for single-step isolation of DNA from biological mixtures is developed. The sorbent is prepared by the polymer deposition from solution onto the surface of porous silica. It is shown that the polymer coating with a thickness of 4 nm is formed not only on the outer surface of the carrier particles but also on the inner pore surfaces. It is found that the material produced largely retained porosity of the pristine support and the material is selective in a one-step separation of nucleic acids and proteins by passing the bacterial lysate through a sorbent. The degree of purification of the isolated preparations of DNA is sufficient to be used directly in PCR analysis.     

Green Lithography for Delicate Materials

A variety of unconventional materials, including biological nanostructures, organic and hybrid semiconductors, as well as monolayer, and other low-dimensional systems, are actively explored. They are usually incompatible with standard lithographic techniques that use harsh organic solvents and other detrimental processing. Here, a new class of green and gentle lithographic resists, compatible with delicate materials and capable of both top-down and bottom-up fabrication routines is developed. To demonstrate the excellence of this approach, devices with sub-micron features are fabricated on organic semiconductor crystals and individual animal's brain microtubules. Such structures are created for the first time, thanks to the genuinely water-based lithography, which opens an avenue for the thorough research of unconventional delicate materials at the nanoscale.     

Thin films used to build generator-type acoustomechanical signal converters

Translated from Izmeritel'naya Tekhnika, No. 4, pp. 37–38, April, 1992.     

Photoelectrochemical oxidation of sulphur dioxide on a polyaniline-modified n-Si/ITO electrode

Surface modification of n-Si/indium tin oxide electrode by photoelectrochemically grown polyaniline film has been shown to result in the dramatic increase in the efficiency of the photoelectrochemical oxidation of SO₂ to SO₄²⁻ in acid medium.