Liquid-Phase-Assisted Sintering of Calcium-Doped Lanthanum Chromites

Investigations have been made on the low-temperature sinterability of calcium-doped lanthanum chromites which are to be used as interconnectors in solid oxide fuel cells (SOFCs). Nominally chromium deficient lanthanum calcium chromites (La_0.7Ca_0.3Cr₁-_yO₃, y = 0.02) were found to be sinterable to 94% theoretical density at 1573 K in air, whereas no densification was observed for samples with y = 0. The two-step shrinkage process suggests a liquid phase sintering mechanism with calcium oxychromates playing an important role as the liquid phase. After sintering at 1573 K, calcium-rich substances remained at grain boundaries.     

Growth and differentiation of eosinophils--special reference to IL-5 and its receptor

IL-5 is a 46 KDa glycoprotein secreted from activated T cells, and plays an important role both in the growth and production of eosinophils. Murine eosinophils have been reported to express high and low affinity receptors. The IL-5 receptor is composed of two membrane protein subunits, alpha and beta subunits. Both alpha and beta chain of mouse and human IL-5 receptor have been identified and sequenced. The alpha subunit is a 60 KDa protein which binds to IL-5 with low affinity. The beta subunit is a 130 KDa protein which does not bind to IL-5 by itself, but forms the high affinity IL-5 receptor in the presence of the alpha subunit. On the other hand, only a high affinity receptor population has been identified on human eosinophils. Affinity cross-linking experiments resulted in the identification of human IL-5 receptor on eosinophils with a molecular mass of 55-60 KDa.     

Oxidation of ferrous iron by acidophilic iron-oxidizing bacteria from a stream receiving acid mine drainage

In this study, the oxidation of ferrous iron by the acidophilic iron-oxidizing bacteria was investigated by field survey and laboratory-scale batch and continuous experiments. The activity of the acidophilic iron-oxidizing bacteria was affected by pH, water temperature and concentration of glucose. The rate of oxidation of pyrite was accelerated by the acidophilic iron-oxidizing bacteria. The number of bacteria attached to the surface of a rotating biological disk changed with the ferrous iron loading.     

CO2 decomposition with oxygen-deficient Mn(II) ferrite

An oxygen-deficient Mn(II) ferrite (Mn_0.97Fe_2.02O_3.92) was synthesized and its reactivity to reduce CO₂ gas into carbon was studied at 300°C. The oxygen-deficient Mn(II) ferrite was obtained by flowing H₂ gas through Mn(II) ferrite with a nearly stoichiometric composition of Mn_0.97Fe_2.02O_4.00 at 300° C. The lattice constant of the oxygen-deficient Mn(II) ferrite (0.8505nm) is larger than that of the Mn(II) ferrite with a nearly stoichiometric composition (0.8498nm). The chemical composition of the Mn(II) ferrite changed from Mn_0.97Fe_2.02O_4.00 to Mn_0.97Fe_2.02O_3.92 during the H₂ reduction process, indicating that the oxygen is deficient in the spinel structure of the Mn(II) ferrite. This was confirmed by Mössbauer spectroscopy and X-ray diffractometry. The efficiency of CO₂ decomposition into carbon at 300°C with the oxygen-deficient Mn(II) ferrite was much lower by about 10⁵ than that of oxygen-deficient magnetite. This is considered to be due to the difference in electron conductivity between Mn(II) ferrite and magnetite, which determines the reductivity for CO₂ into carbon by donation of an electron at the adsorption site.     

Electrical properties and microstructure in the system ceria-alkaline earth oxide

The ionic conduction of oxygen in the ceria-alkaline earth oxide system was investigated as a function of temperature, partial pressure of oxygen and oxide composition, together with its crystal structure, density, and microstructure. Undoped ceria and its solid solution with alkaline earth oxides have a cubic fluorite structure. The ionic conductivity of ceria is greatly enhanced by additions of calcia and strontia, even when they are added in excess of the solubility limit. The conductivities of ceria-calcia and ceria-strontia were much higher than those of calcia-and yttria-stabilized zirconia. Up to the limit of calcia and strontia, the ionic transference number was nearly unity in the temperature range between 600 and 900°C. With an increase in calcia and strontia content, the ionic conductivity was little affected by the presence of a second phase of CaO and SrCeO₃.     

An application of Cohen's result on star height to the theory of control structures

A result/concept on star height is applied to two problems in the theory of control structures. First, Kosaraju's systems RE_n of control structures are generalized and it is shown by using Cohen's result on star height that the generalized systems constitute a pathwise hierarchy with respect to their expressive powers. Second, by using a concept on star height, a result of Peterson et al. (Comm. ACM16 (1973), 503–512) that RE_∞ is pathwise complete is sharpened.     

Referral patterns in ethnic-specific and mainstream programs for ethnic minorities and Whites.

The present study examined the referral patterns of 1,095 African, 2,168 Asian, 1,385 Hispanic, and 2,273 White Americans (18 years of age and older) in a public mental health system to determine whether group differences in help-seeking and referral patterns were related to participation in ethnic-specific versus mainstream programs. Results indicated that (a) ethnic minorities in both mainstream and ethnic-specific programs were more likely than Whites to have been referred by natural help-giving and lay referral sources (e.g., family or friends, health services, and social services) and (b) ethnic minorities in ethnic-specific programs were more likely than ethnic minorities in mainstream programs to have been referred by natural help-giving and lay referral sources if they were Asian and Hispanic Americans and self-referred if they were African Americans. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mean systemic pressure and mean pulmonary pressure: their effects on the total artificial heart

Mean systemic pressure (MSP) and mean pulmonary pressure (MPF), which are mean driving pressures for venous return in the natural heart, were studied in 11 calves in which the natural heart had been replaced with a total artificial heart (TAH). They were measured simply by stopping the artificial heart pumping. Although blood translocation from the arterial to the venous side was not performed, the eventual right and left atrial pressures reached six to eight seconds after stopping the TAH would represent MSP and MPP with reasonable accuracy. The MSP varied from nine to 3k mmHg (20+/-6 mmHg), whereas the MPP varied from nine to 39 mmHg (22+/-7 mmHg). The MSP varied in close relation to the right atrial pressure prior to cessation of the TAH (r=0.9124). Increases in RAP and MSP were mainly attributed to an increase in circulating blood volume. In the performance of the TAH, MSP (or MPP), proper diastolic duration and vacuum application during diastole was of prime importance in determining the end-diastolic ventricular volume.