Information-measuring diagnostics complex for technical maintenance

Hardware-software complex for configuration, support and diagnostics of control systems in aircraft engines and allied devices is described. Application of certain algorithms based on a bank of Kalman filters to detect parametric faults in sensors and actuators is considered.     

Application of a standard two-stage transformer for checking purposes

Conclusions A standard two-stage current transformer at a frequency of 50 Hz when operating with domestic differential-null comparison instrument is not less accurate than three-winding magnetic current comparators and is superior to them in its speed of measurement and portability. For a simple and economic modernization of the standard measuring facilities employed in the USSR to check commercial-frequency current transformers the three-winding magnetic current comparators and uncompensated transformers should be replaced by standard two-stage current transformers.Translated from Izmeritel'naya Tekhnika, No. 5, pp. 65–67, May, 1980.     

Progressive systemic sclerosis: intrathecal pain management

PURPOSE: To determine if lucanthone crossed the blood-brain barrier in experimental animals; and to determine accelerated tumor regression of human brain metastases treated jointly with lucanthone and whole brain radiation. METHODS AND MATERIALS: The organ distribution of 3H lucanthone in mice and 125I lucanthone in rats was determined to learn if lucanthone crossed the blood-brain barrier. Size determinations were made of patients' brain metastases from magnetic resonance images or by computed tomography before and after treatment with 30 Gy whole brain radiation alone or with lucanthone. RESULTS: The time course of lucanthone's distribution in brain was identical to that in muscle and heart after intraperitoneal or intravenous administration in experimental animals. Lucanthone, therefore, readily crossed the blood-brain barrier in experimental animals. CONCLUSION: Compared with radiation alone, the tumor regression in patients with brain metastases treated with lucanthone and radiation was accelerated, approaching significance using a permutation test at p = 0.0536.     

Structure-based design of inhibitors specific for bacterial thymidylate synthase

Thymidylate synthase is an attractive target for antiproliferative drug design because of its key role in the synthesis of DNA. As such, the enzyme has been widely targeted for anticancer applications. In principle, TS should also be a good target for drugs used to fight infectious disease. In practice, TS is highly conserved across species, and it has proven to be difficult to develop inhibitors that are selective for microbial TS enzymes over the human enzyme. Using the structure of TS from Lactobacillus casei in complex with the nonsubstrate analogue phenolphthalein, inhibitors were designed to take advantage of features of the bacterial enzyme that differ from those of the human enzyme. Upon synthesis and testing, these inhibitors were found to be up to 40-fold selective for the bacterial enzyme over the human enzyme. The crystal structures of two of these inhibitors in complex with TS suggested the design of further compounds. Subsequent synthesis and testing showed that these second-round compounds inhibit the bacterial enzyme at sub-micromolar concentrations, while the human enzyme was not inhibited at detectable levels (selectivities of 100-1000-fold or greater). Although these inhibitors share chemical similarities, X-ray crystal structures reveal that the analogues bind to the enzyme in substantially different orientations. Site-directed mutagenesis experiments suggest that the individual inhibitors may adopt multiple configurations in their complexes with TS.     

Heterogeneous catalysis in ionic liquids: The heck reaction of bromobenzene with styrene over palladium supported on mesoporous carbon

Tributylhexylammonium bistriflamide [(C₄H₉)(C₆H₁₃)N][(CF₃SO₂)₂N], an ionic liquid, was used as a solvent for the Heck reaction of bromobenzene with styrene in the presence of Pd deposited onto a mesoporous carbon support. It was found that dibutylamine used as a basic reagent to scavenge hydrogen bromide results in higher conversions of the reactants and higher yields of stilbene than sodium acetate. It was shown that the IL is fully recoverable after use in the catalytic reaction.     

The concept of elementary excitations in classical statistical mechanics

Exact representations of the generating functional of one-component classical systems with a central interatomic interaction potential are obtained in terms of the functional integrals over auxiliary fields determined in the wavevector space. It is proved that the problem of calculating a classical partition function for a system of particles with an arbitrary interatomic interaction potential is equivalent to the problem of calculating a statistical integral for a system of interacting oscillators with a temperature-dependent Hamiltonian.     

Investigation of the structure of the secondary flow in blade systems of francis turbines

Conclusion Knowing the regularities of the change in the secondary flows in relation to the runner geometry, we can more validly solve the problem of its optimal design. For illustration we give an example of designing a runner of the RO-75 mixed-flow type in which owing to an improvement of its shape it was possible to substantially reduce secondary velocities and secondary energy losses compared with one of the presently best variants of the given type of runner [9]. Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 2, pp. 18–22, February, 1997.