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Using the methods of optically stimulated electron emission (OSEE) and ambient pressure photoemission spectroscopy (APS), the energy characteristics of carbyne-containing films on copper and silicon substrates have been studied. The average contact potential difference and the work function were determined, and the positions of the Fermi level for carbyne-containing films of various thicknesses were calculated. It was found that the electrons work function and the position of the Fermi level of the studied film samples do not depend on the film thickness and the type of substrate. The information content of the OSEE and APS methods for evaluating the quality of carbon coatings on substrates is shown. [ABSTRACT FROM AUTHOR]

Tautomeric equilibria of 5-nitrobarbituric acid and 1,3-dimethyl-5-nitrobarbituric acid were studied by NMR, UV, and IR spectroscopy, as well as by quantum-chemical methods. These compounds were found to exist in the gas phase, in solutions in water and DMSO, and in crystal as the corresponding enol tautomers. In trifluoroacetic and chloroform solutions, an equilibrium mixture of the ketone and enol forms was detected. The parameters determining the state of the tautomeric equilibrium are the total energy of a tautomer, its deprotonation energy, and a component of the latter, which relates to electrostatic interaction between the mobile proton and the rest of the molecule. Proton-donor and proton-acceptor properties of the solvent and 5-nitro-2,4,6-pyrimidinetrione derivatives are the main factors responsible for displacement of the tautomeric equilibrium in solution; electrostatic solvation and tautomer stabilization via hydrogen bonding are less significant. [ABSTRACT FROM AUTHOR]

Samples of high-temperature superconducting (HTSC) ceramics YBa2Cu3O7–δ thermally treated in oxidizing and reducing media are investigated by means of the exoelectron emission method. It is found that the thermostimulated exoemission (TSE) increases considerably in the maximum at 470 K after reducing thermal treatment of HTSC ceramics at temperatures of 800–860 K. Correlation dependences between the exoemission activity, the deviation from the stoichiometry in the oxygen sublattice, and the temperature of transition of YBa2Cu3O7–δ ceramics to the superconducting state are found. These dependences indicate that the exoemission testing can be used in the design of technologies of the synthesis and treatment of HTSC materials on the basis of complex oxides. [ABSTRACT FROM AUTHOR]

The current study was designed to investigate direct inhibitory effects of N-acetyl-glucosaminyl-muramyldipeptide (GMDP) over the cytotoxic nature of TNF-alpha. A lactate dehydrogenase (LDH) assay of the inhibition of TNF-alpha cytotoxicity was done in vitro on the following cell lines: A549 (human lung carcinoma cells), A431 (human breast cancer cells) and L929 (mouse breast cancer cells). In a double-blind placebo-controlled trial, cancer patients with an elevated activity of all five LDH isoensymes were randomized to receive either a GMDP solution or a placebo; 63 patients were evaluated every third day for the mean daily number of episodes of nausea or vomiting, changes in clinical status, cell blood count and blood chemistry. A 95% inhibition of LDH release was noticed on A549 cells. Other cell lines were less sensitive to GMDP, with an observed 72% dose-dependent reduction in LDH activity. In vivo, LDH activity was decreased by 41% (+/-4%) (mean+/-SD) in all 21 subjects who were given 0.5-1.0 mg of GMDP daily. A lowering of LDH activity by 73.4% (+/-4%) was observed in 23 patients who received GMDP at a dosage of 1.5mg/kg daily. Correspondingly, a 10% (+/-2%) increase in LDH activity was noticed in 19 patients who were given a placebo (P < 0.01). During the follow-up period, the overall clinical condition of all patients treated with GMDP was improved. No side effects were observed. In nine patients who experienced nausea from tumor toxicity before treatment, the symptom subsided. In parallel, an extremely beneficial effect on lipids metabolism was noticed in all patients with elevated cholesterol and trigliceride levels. A dietary supplementation of GMDP has been shown to reduce systemic TNF-alpha cytotoxicity during tumor shock. [ABSTRACT FROM AUTHOR]

New high-temperature peaks of thermostimulated exoelectron emission (TSEE) from uranium-activated LiF and NaF Crystals were observed. TSEE parameters for various (Li,Na)-(U+Me) systems were determined. [ABSTRACT FROM AUTHOR]

The method of photostimulated electron emission is used to investigate the processes responsible for redistributing charges formed by photoionization of F centers in anion-defective corundum single crystals in an external electric field. It is shown that the observed features of the excitation spectra are due to conversion transitions between F and F[sup +] centers, whose probability in the surface layer of the crystal is much higher than in the interior because of the high excitation density and the presence of an electric field. The results obtained could be of interest for studying radiation-stimulated phenomena in dielectric materials. [ABSTRACT FROM AUTHOR]

Characterizes DNA topoisomerase V, a prokaryotic counterpart to the eukaryotic topoisomerase I in the hyperthermophilic methanogen Methanopyrus kandleri. Time course and temperature dependence of activity; Relaxation with supercoiled DNA; Formation of a covalent complex with the 3' end of the broken DNA strand; Recognition by antibody raised against topoisomerase I.

Samples of high-temperature superconducting (HTSC) ceramics YBa2Cu3O7–δ thermally treated in oxidizing and reducing media are investigated by means of the exoelectron emission method. It is found that the thermostimulated exoemission (TSE) increases considerably in the maximum at 470 K after reducing thermal treatment of HTSC ceramics at temperatures of 800–860 K. Correlation dependences between the exoemission activity, the deviation from the stoichiometry in the oxygen sublattice, and the temperature of transition of YBa2Cu3O7–δ ceramics to the superconducting state are found. These dependences indicate that the exoemission testing can be used in the design of technologies of the synthesis and treatment of HTSC materials on the basis of complex oxides. [ABSTRACT FROM AUTHOR]