Deactivation and regeneration of oxygen reduction reactivity on double perovskite Ba2Bi0.1Sc0.2Co1.7O6−x cathode for intermediate-temperature solid oxide fuel cells

in situ high-temperature X-ray diffraction and thermal gravimetric- differential thermal analysis on room-temperature powder, as well as X-ray diffraction, Raman spectroscopy, and transmission electron microscopy on quenched powder, were applied to study crystal structure and phase transformations in Ba₂Bi_0.1Sc_0.2Co _1.7O_6-x (BBSC). Heating BBSC in air to over 800 °C produces a pure cubic phase with space group Fm3m (no. 225), and cooling down below 800 °C leads to a mixture of three noncubic phases including an unknown phase between 200 and 650 °C, a 2H hexagonal BaCoO3 with space group P63/mmc (no. 194) between 600 and 800 °C, and an intermediate phase at 800 °C. These three phases exist concurrently with the major cubic phase. The weight gain and loss between 300 and 900 °C suggest the occurrence of cobalt reduction, oxidation, and disproportion reactions with dominant reduction reaction at above 600 °C. The thermal expansion of BBSC was also examined by dilatometry. BBSC has a highly temperature-dependent thermal expansion coefficient which relates well with its structure evolution. Furthermore, the oxygen reduction reaction (ORR) of BBSC was probed by symmetrical cell and three-electrode configurations. The presence of hexagonal phase at 700 °C rarely affects the ORR performance of BBSC as evidenced by a slight increase of its area-specific resistance (ASR) value following 48 h of testing in this three-electrode configuration. This observation is in contrast to the commonly held point of view that noncubic phase deteriorates performance of perovskite compounds (especially in oxygen transport applications). Moreover, cathodic polarization treatment, for example, current discharge from BBSC (tested in three-electrode configuration), can be utilized to recover the original ORR performance. The cubic structure seems to be retained on the cathodic polarization - the normal cathode operating mode in fuel cells. Stable 72-h performance of BBSC in cathodic polarization mode further confirms that despite the presence of phase impurities, BBSC still demonstrates good performance between 500 and 700 °C, the desired intermediate operating temperature in solid oxide fuel cells.

The influence of solute carbon in cold-rolled steels on shear band formation and recrystallization texture

Two experiments were conducted to clarify the roles of grain size, solute carbon and strain in determining the recrystallization textures of cold-rolled and annealed steels. In the first experiment, samples of coarse-grained low-carbon (LC) and interstitial-free (IF) steels were cold-rolled to a 75% reduction in thickness. One sample from each steel was polished and cold-rolled an additional 5%, while the remaining samples were annealed for various times at 650°C. In the second experiment, three samples from a commercial LC steel sheet were rolled 70% at 300°C. Two of the samples were given a further rolling reduction of 5% of the original thickness, with one of the samples being given this additional reduction at 300°C and the other at room temperature. Goss recrystallization textures are strengthened by coarse initial grain sizes, the presence of solute carbon and rolling at a temperature where dynamic strain ageing occurs, but are weakened by additional rolling beyond a reduction of 70%, especially when this extra rolling is conducted at a temperature where dynamic strain ageing does not occur. Characterization of key features of the deformed and recrystallized steels using optical microscopy, scanning electron microscopy (SEM) and electron back-scatter diffraction (EBSD) supports a rationale for these effects based on the repeated activation and deactivation of shear bands and the influence of solute carbon and dynamic strain ageing on the operating life of the bands and the accumulation of strain within them.

Mining frequent patterns for AMP-activated protein kinase regulation on skeletal muscle

Background
AMP-activated protein kinase (AMPK) has emerged as a significant signaling intermediary that regulates metabolisms in response to energy demand and supply. An investigation into the degree of activation and deactivation of AMPK subunits under exercise can provide valuable data for understanding AMPK. In particular, the effect of AMPK on muscle cellular energy status makes this protein a promising pharmacological target for disease treatment. As more AMPK regulation data are accumulated, data mining techniques can play an important role in identifying frequent patterns in the data. Association rule mining, which is commonly used in market basket analysis, can be applied to AMPK regulation.

Results
This paper proposes a framework that can identify the potential correlation, either between the state of isoforms of α, β and γ subunits of AMPK, or between stimulus factors and the state of isoforms. Our approach is to apply item constraints in the closed interpretation to the itemset generation so that a threshold is specified in terms of the amount of results, rather than a fixed threshold value for all itemsets of all sizes. The derived rules from experiments are roughly analyzed. It is found that most of the extracted association rules have biological meaning and some of them were previously unknown. They indicate direction for further research.

Conclusion
Our findings indicate that AMPK has a great impact on most metabolic actions that are related to energy demand and supply. Those actions are adjusted via its subunit isoforms under specific physical training. Thus, there are strong co-relationships between AMPK subunit isoforms and exercises. Furthermore, the subunit isoforms are correlated with each other in some cases. The methods developed here could be used when predicting these essential relationships and enable an understanding of the functions and metabolic pathways regarding AMPK.

Degradation of VOCs using non-film titania in a hybrid process

This study reports the preparation and characterization of titanium dioxide (TiO2)-based non-film catalysts, reactor design and their utilization in a hybrid dynamic degradation of acetone and toluene. The behaviours of deactivation and regeneration of catalysts are explored as well. The regression equations of conversion rate in differing operating modes are concluded.