Dynamic methods for calibration and verification of the metrological characteristics of instruments intended for gas analysis (generalized approach)

A systematic approach to the metrological provision (MP) of gas-analytical measurements in the range of microconcentrations (trace analysis) using dynamic and static control facilities is described. Results of investigations and development of the methods and facilities for continuous preparation of reference gas mixtures (RGMs) for the MP of commercial chromatographs, chemical sensors, and other instruments and devices for gas analysis are presented, including data on the capacity of adsorbents, parameters of sampling adsorption tubes, regimes of sorption and desorption, creation and maintenance of gas mixtures with preset compositions in testing chambers for toxicological investigations. Methodological and technical problems of MP in the field of trace analysis are considered. The main dynamic methods of preparation of the RGMs by flow mixing, diffusion leak, and exponential dilution of initial gases are described. Examples of the new generation of new “smart” systems of the Mikrogaz-F type intended for the RGM preparation in the range of microconcentrations are presented.     

Epitopes of the P-fimbrial adhesin of E. coli cause different urinary tract infections

PURPOSE: This is a study of the interaction of the tip protein of P-fimbriae E. coli, its specific urothelial adhesin, and urothelial receptors for the adhesin. This tip protein has several epitopes that adhere to different isoreceptors containing the urothelial alpha-gal-1-4 beta-gal disaccharide. Renal tubular cells of our monkey model contain the globoside isoreceptor, and thus ureteral inoculation of E. coli with the class II tip protein leads to pyelonephritis. The class III tip protein adheres to the Forssman antigen and causes cystitis in humans. MATERIALS AND METHODS: An E. coli strain, DS17 which originally caused pyelonephritis in a child, is P-fimbriated and contains a class II tip adhesin. A mutant was produced to contain a class III tip adhesin. Eight monkeys had a ureteral inoculation of E. coli DS17 and 4 monkeys with E. coli DS17-1. In addition, we studied in vitro adherence by these strains. RESULTS: We show that in vitro adherence by the tip protein of P-fimbriae to bladder cells of the monkey occurs by several mechanisms, adhering to specific receptors for the class II and III epitopes of the tip protein as well as by means of type 1 fimbriae. In addition, the PapE protein of the fibrillum of the P-fimbriae adheres to fibronectin. As always, electrostatic and hydrophobic interaction remain important contributions to adherence. E. coli DS17 caused pyelonephritis, but DS17-1 caused cystitis. Bacteriuria was prolonged by DS17 infection. CONCLUSION: The site of a urinary tract infection from P-fimbriated E. coli can be predicted by the epitope of the tip protein of P-fimbriae.     

Liver-directed gene transfer in non-human primates

To develop a primate model for liver-directed gene therapy, we studied several gene transfer vehicles and routes in eight rhesus monkeys (Macaca mulatta). For this purpose, we used first-generation, replication-deficient adenoviral vectors carrying the Escherichia coli lacZ gene (Ad.CMVlacZ) or a lacZ-containing plasmid (pCMV beta) with lipofectamine for transfection. The reporter gene construct was infused into either the portal vasculature, common bile duct, or saphenous vein. Adenovirus-mediated gene transfer via the portal vein resulted in expression of lacZ in over 70% of hepatocytes by days 3-7, but was accompanied by acute hepatitis. Adenovirus-mediated gene transfer via the common bile duct resulted in lacZ expression in less than 10% of hepatocytes and was accompanied by portal inflammation. The animals mounted a significant immune response, as demonstrated by adenoviral antigen-induced T-cell proliferation and production of neutralizing anti-adenovirus antibodies and antibodies to E. coli beta-galactosidase (beta-Gal). Activation of the immune response was associated with rapid decrease of the reporter gene by days 13-21. Lipofectamine-mediated gene transfer was inefficient, and no lacZ expression in the liver was detected. To limit the host immune response, 4 animals were immunosuppressed by cyclophosphamide/prednisone and then infused with the Ad.CMVlacZ via the portal vein or the saphenous vein. The monkeys showed sustained expression of lacZ for up to 35 days with no evidence of inflammation. The primates transduced via the saphenous vein showed a level of beta-Gal expression in the liver similar to that of the portal vein-infused animals. In conclusion, adenovirus-mediated gene transfer to non-human primate livers via the portal vein or saphenous vein is efficient, but it results in transient expression and is accompanied by an immune response to both vector and transgene products and acute hepatitis, whereas lipofectamine-mediated transfer is inefficient. Manipulation of the host immune response may expand potential applications of adenoviral vectors for liver-directed gene transfer.     

Dynamics of the sorption of hydrogen chloride and ammonia on the carboxyl group-containing fibre VION KN-1

Conclusions Using a dynamic assembly of the Mikrogaz type for the preparation of gas mixtures of known composition, the sorption of hydrogen chloride and of ammonia has been studied in the concentration range from 0.5 to 1000 mg/m³, under dynamic conditions on the nonwoven chemisorptive fibrous material VION, type KN-1. Regimes for the desorption of these materials and regeneration of the sorbent have been selected.The possibility of fine clean-up of gas discharges of hydrogen chloride and of ammonia on VION KN-1 has been demonstrated, plus the conditions for effecting it, as well as the possibility of using this material for mean shift and mean daily quantitative air sampling.Translated from Khimicheskie Volokna, No. 6, pp. 48–50, November–December, 1987.     

Evaluation of the reliability and endurance of structures on the basis of results of accelerated tests of elements

Using a newly devised method of processing accelerated tests when the distribution functions of breakdowns are unknown, the author obtained equations of the endurance of elements made of steels 15Kh5M and 15Kh5M_e. A formula is derived correlating the reliability of a structure with the reliability of a structural element. The article shows that the solution of the problem of the reliability of operation of a structure in the course of the stipulated service life depends on the area of the structure and the required magnitude of the reliability of its troublefree operation.Translated from Problemy Prochnosti, No. 2, pp. 52–55, February, 1991.     

A comparison of two analogue strategies for assessing children's social skills.

Compared 2 analog strategies for assessing 66 4th–5th grade children's social skills to determine if the 2 yield different response styles. Role-play scenes and a naturalistic scene were utilized. Results indicate that more behaviors occurred in the role-play strategy than in the naturalistic strategy. Judges assigned higher ratings of likability in the role-play scenes than they did in the naturalistic scene. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fullerene C<Subscript>60</Subscript> diffusion in thin layers of amorphous polymers: Polystyrene and poly(α-methylstyrene)

The outdiffusion of fullerene C₆₀ from submicron films of polymer-fullerene blends has been studied by thermodesorption mass spectrometry (TDMS). The energy parameters of C₆₀ diffusion in polystyrene and poly(α-methylstyrene) were determined and compared to the parameters of desorption of C₆₀ molecules from a multilayer film of pure fullerene deposited onto a substrate from toluene solution.