Bismuth oxide based ceramics with improved electrical and mechanical properties: Part II. Structural and mechanical properties

Coprecipitation as a method of preparation for bismuth oxides based ceramics yields relatively strong and machineable materials in comparison with the solid state reaction. Compositions within the system (1−x)Bi2O3|xEr2O3 containing up to twenty five mole percent of erbium oxide show a slow transition on heating at 900 K from a cubic to a hexagonal (rhombohedral) phase. The resulting hexagonal phase is stable up to 1000 K where it transforms back to the cubic phase. Long term heating at 775 K causes formation of traces of ∝ - bismuth oxide in these samples, but the material itself remains cubic. Compositions containing thirty mole percent of erbium oxide do not show any such changes and hence are suitable for application purposes

Luminescent thin films by the chemical aerosol deposition technology (CADT)

Zinc sulphide thin films have been deposited with CART using zinc chlorideand zinc acetylacetonate as Zn compounds and thiourea and 1,1,3,3-tetramethylthiourea as S compounds soluted in methanol, ethanol, isopropanol and cellosolve. After optimalization of the deposition process homogeneous layers with a c-axis oriented hexagonal columnar structure with a high density (up to 96%) were obtained. Luminescence was observed with films grown above 500°C. The influence of the hot plate temperature, flow of carrier gas, nozzle geometry, distance nozzle substrate, and volatility of the solvent and reactants on the growth rate, homogenity and density of the film has been shown. Some rules for the selection of the starting compound are given. TG analyses of the reactant compounds was used to compare their volatility and stability

Світоглядні основи традиційної слов’янської темпоральності

This article generalizes the results of the research on the particularities of the understanding of the time conception in traditional mythological picture of the world of the East Slavs. The semantics and typology of time in traditional agricultural communities is described by the author as well as its connections to other traditional categories like birth, life and death. Author is explaining the limited by the special categories borders of the traditional folk temporality

Electrical and catalytic properties of some oxides with the fluorite or pyrochlore structure: Part 2: Catalytic oxidation of carbon monoxide

The catalytic properties of mixed oxides with the fluorite or pyrochlore structure were investigated using CO oxidation. The presence of ions with a variable valence state, the size of the ions and especially the extent of pyrochlore ordering affect kinetic behaviour and activity of the investigated materials

Electrical and catalytic properties of some oxides with the fluorite or pyrochlore structure: Part 1: Synthesis, characterization and conductivity

In view of their possible use as electrocatalysts, several oxides with the fluorite or pyrochlore structure were investigated. Part I of this paper deals with the synthesis, characterization and electrical conductivity of these materials. All lanthanide titanates investigated (partly doped with Bi) show the pyrochlore structure and are poor conductors, except for the compounds containing Tb. For Nd-zirconates, partly substituted with Ce, the degree of order depends on the amount of Ce and temperature treatment. Ionic and in some cases mixed conductivity was observed. Part II reports about the catalytic activity for CO oxidation

Loss of Bcl-2 in invasive breast cancer is associated with high rates of cell death, but also with increased proliferative activity.

Bcl-2 has been demonstrated to inhibit apoptosis in breast cancer cells in vitro, and the ratio between Bcl-2 and its proapoptotic homologue Bax seems to be an important determinant of cellular sensitivity to induction of apoptosis. However, little information is available on the relationship between Bcl-2 and the rate of apoptotic and necrotic cell death in breast tumours. From a series of 441 premenopausal, lymphnode-negative breast cancer patients, a subset of 49 tumours was selected in which immunostaining for the 26-kDa isoform of Bcl-2 was either absent (n = 23) or very high (n = 26). High expression of Bcl-2 was found to be strongly associated with low rates of apoptotic (P < 0.001) and necrotic cell death (P < 0.001). The mean value of the apoptotic index was 2.69%+/-1.40% in Bcl-2-negative tumours and 0.68%+/-1.00% in Bcl-2-positive tumours. Expression of the proapoptotic protein Bax correlated neither with Bcl-2 nor with the frequency of apoptotic cells. Immunostaining for the antiapoptotic Bcl-2 homologue BcI-X(L) correlated with Bcl-2 expression (P < 0.001) but not with apoptosis. High proliferation rate and high tumour grade (Bloom-Richardson) were strongly associated with absence of Bcl-2 expression (P< 0.001). p53 accumulation was associated with absence of Bcl-2 expression and increased apoptotic activity. Loss of Bcl-2 expression was strongly correlated with increased apoptotic and necrotic cell death, high proliferation rate and high tumour grade, supporting a model in which Bcl-2 not only mediates cell death, but also cell division in breast cancer tissue, and in which regulation of cell division and cell death are tightly linked

Learning in Cobweb Experiments

Different theories of expectation formation and learning usually yield different outcomes for realized market prices in dynamic models. The purpose of this paper is to investigate expectation formation and learning in a controlled experimental environment. Subjects are asked to predict the next period's aggregate price in a dynamic commodity market model with feedback from individual expectations. Subjects have no information about underlying market equilibrium equations, but can learn by observing past price realizations and predictions. We conduct a stable, an unstable, and a strongly unstable treatment. In the stable treatment, rational expectations (RE) yield a good description of observed aggregate price fluctuations: prices remain close to the RE steady state. In the unstable treatments, prices exhibit large fluctuations around the RE steady state. Although the sample mean of realized prices is close to the RE steady state, the amplitude of the price fluctuations as measured by the variance is significantly larger than the amplitude under RE, implying persistent excess volatility. However, agents' forecasts are boundedly rational in the sense that fluctuations in aggregate prices are unpredictable and exhibit no forecastable structure that could easily be exploited

In vitro cultures of pupal integumental explants to bioassay insect growth regulators with ecdysteroid activity for ecdysteroid amounts and cuticle secretion

The present study evaluated the in vitro bioassay with pupal integumental explants of the mealworm Tenebrio molitor to test the activity of two types of insect growth regulators (IGRs) with ecdysteroidal action. We assessed the imidazole derivative KK-42, that is know as ecdysteroid biosynthesis inhibitor, and the dibenzoylhydrazine RH-0345 (halofenozide) that representing a novel group of IGRs with ecdysteroid agonist action. Two biological endpoint were used, namely the production of ecdysteroid hormone and cuticle secretion in vitro. Also the test was done with and without renewment of the culture medium to test the persistence of action of each compound. Essentially, RH-0345 provoked higher ecdysteroid amounts, while KK-42 a reduction. Interestingly when KK-42 was followed by RH-0345, the inhibitory effect was compensated. In parallel, the deposition of cuticle in vitro was assessed and it was clear that RH-0345 could induce apolysis premature in the integument explants with the formation of a new cuticle. Here the protein and chitin contents of the explants were tested with RH-0345 and three analogous compounds, RH-2485, RH-5992 and RH-5849