Prediction of changes in the metrological characteristics of channels with sensors

A method is proposed for determining the errors of sensors built into industrial apparatus which cannot be removed during periodic checks (calibrations). This method makes it possible to predict the maximum period for which a sensor forming part of a measuring channel can be operated before its error reaches the maximum permissible value.Translated from Izmeritel'naya Tekhnika, No. 11, pp. 9–10, November, 1994.     

Human gamma-interferon expression in the mammary gland of transgenic mice

Transgenic mice carrying a hybrid gene consisting of ovine beta-lactoglobulin gene sequences and human gamma-interferon (hIFN-g) cDNA were produced. hIFN-g expression in the mammary gland of two lactating transgenic founder females was found. The concentration of active hIFN-g in the milk was estimated as being ca. 1800 IU/ml. The hIFN-g ability to express in the mammary gland was found in the progeny of transgenic founder male.     

Surface adsorption of comb polymers by Monte Carlo simulations

This paper reports off-lattice Monte Carlo simulations of highly-branched comb homopolymers weakly adsorbed on a flat, featureless surface showing only covolume and dispersion interactions with the adsorbate. A minimal coarse-grained model, described by hard spheres connected by harmonic springs, was employed. The interaction energy of the adsorbed combs and linear chains is first discussed as a function of the molecular mass and of the number of beads in contact with the surface. The molecular size is then investigated as a function of backbone length and branching density at a fixed arm size. The apparent swelling exponents of the adsorbed combs are larger than those of the corresponding linear chains, and much larger than that of the free molecules. This result indicates a surface-induced stiffening of the comb backbone, further studied through the persistence length l_pers. It is found that l_pers increases upon adsorption over the free-molecule value, more so the larger is the branching density. Finally, the thickness of the adsorbed layer, the surface-induced molecular anisotropy and the molecular aspect ratio are investigated as a function of branching density and molecular mass.     

Galvanomagnetic properties of 3C-SiC epilayers grown on hexagonal SiC substrates

Epitaxial 3C-SiC films have been grown on 6H-SiC substrates by sublimation epitaxy in vacuum. The Hall effect in these heterostructures and their magnetoresistance have been measured in a temperature range from 1.4 to 300 K. At liquid-helium temperatures, the samples are characterized by low resistance and exhibit negative magnetoresistance in weak fields (～1 T). Analysis of the experimental results suggests that the low resistance of samples is most probably due to the metal-insulator transition in the epitaxial 3C-SiC films.     

Genetic transformation of Vitreoscilla sp

Of all the methods customarily used to transform E. coli we found only electroporation to be effective for transformation of the Gram-negative bacterium Vitreoscilla, yielding 5.10(5) transformants/microgram of plasmid DNA. The conditions used were close to those described for E. coli E. coli plasmids are stably maintained in Vitreoscilla. This is the first report of exogenous DNA transfer in Vitreoscilla which opens the way for the application of recombinant-DNA techniques to study this unique group of organisms.     

On the possibility of PID control of the standard inertial and oscillatory plants

Stability-optimal solutions were established for the problem of control of the aperiodic, delay, and oscillatory plants approximated by the dynamic models representing a serial connection of the inertial units, inertial delay unit, and inertial units with oscillatory unit.