<i>Bacillus thuringiensis</i> Spores and Cry3A Toxins Act Synergistically to Expedite Colorado Potato Beetle Mortality

The insect integument (exoskeleton) is an effective physiochemical barrier that limits disease-causing agents to a few portals of entry, including the gastrointestinal and reproductive tracts. The bacterial biopesticide Bacillus thuringiensis (Bt) enters the insect host via the mouth and must thwart gut-based defences to make its way into the body cavity (haemocoel) and establish infection. We sought to uncover the main antibacterial defences of the midgut and the pathophysiological features of Bt in a notable insect pest, the Colorado potato beetle Leptinotarsa decemlineata (CPB). Exposing the beetles to both Bt spores and their Cry3A toxins (crystalline δ-endotoxins) via oral inoculation led to higher mortality levels when compared to either spores or Cry3A toxins alone. Within 12 h post-exposure, Cry3A toxins caused a 1.5-fold increase in the levels of reactive oxygen species (ROS) and malondialdehyde (lipid peroxidation) within the midgut – key indicators of tissue damage. When Cry3A toxins are combined with spores, gross redox imbalance and ‘oxidation stress’ is apparent in beetle larvae. The insect detoxification system is activated when Bt spores and Cry3A toxins are administered alone or in combination to mitigate toxicosis, in addition to elevated mRNA levels of candidate defence genes (pattern-recognition receptor, stress-regulation, serine proteases, and prosaposin-like protein). The presence of bacterial spores and/or Cry3A toxins coincides with subtle changes in microbial community composition of the midgut, such as decreased Pseudomonas abundance at 48 h post inoculation. Both Bt spores and Cry3A toxins have negative impacts on larval health, and when combined, likely cause metabolic derangement, due to multiple tissue targets being compromised

Design of Anode Materials for IT SOFC:Effect of Complex Oxide Promoters and Pt Group Metals on Activity and Stability in Methane Steam Reforming of Ni/YSZ (ScSZ) Cermets

Ni/YSZ or Ni/ScCeSZ cermets were promoted by up to 10 wt % of fluoritelike (Pr-Ce-Zr- O, La-Ce-Zr-O, and Ce-Zr-O) or perovskitelike (La-Pr-Mn-Cr-O) oxides and small (up to 1.4 wt %) amounts of Pt group metals (Pd, Pt, or Ru). Reactivity of samples, their lattice oxygen mobility, and their ability to activate methane were characterized by temperature-programed reduction by CH4. The catalytic properties of these samples in methane steam reforming were studied at 500-850 degrees C and short contact times (10 ms) in feeds with 8 mol % of CH4 and steam/methane ratio of 1: 3. Oxide promoters ensure stable performance of cermets in stoichiometric feeds at T &gt; 650 degrees C by suppressing carbon deposition. Copromotion with precious metals enhances performance in the intermediate temperature (450-600 degrees C) range due to more efficient activation of methane. Factors determining specificity of these cermet materials' performance (chemical composition, microstructure, oxygen mobility in oxides, interaction between components, and reaction media effect) are considered. The most promising systems for practical application are Pt/Pr-Ce-Zr-O/Ni/YSZ and Ru/La-Pr-Mn-Cr-O/Ni/YSZ cermets demonstrating a high performance in the intermediate temperature range under broad variation in steam/CH4 ratio. [DOI: 10.1115/1.3117255]</p

Design of Anode Materials for IT SOFC: Effect of Complex Oxide Promoters and Pt Group Metals on Activity and Stability in Methane Steam Reforming of Ni/YSZ &quot;ScSZ… Cermets

small (up to 1.4 wt %) amounts of Pt group metal

Design of anodes for IT SOFC: Effect of complex oxide promoters and pd on activity and stability in methane steam reforming of Ni/YSZ (ScSZ) cermets

Effect of fluorite-like or perovskite-like complex oxide promoters and Pd on the performance of Ni/8YSZ and Ni/ScSZ anode materials in CH4 steam reforming (SR) or selective oxidation (SO) by O-2 into syngas was studied. The spatial uniformity of dopants distribution in composites was controlled by TEM combined with EDX analysis, while the lattice oxygen mobility and reactivity were estimated by CH4 and H-2 temperature-programmed reduction (TPR). The oxide promoters suppress the coke deposition even at stoichiometric H2O/CH4 ratio, while doping by Pd ensures a good performance at moderate (similar to 550 degrees C) temperatures required for the Intermediate -Temperature Solid Oxide Fuel Cells (IT SOFC) operation.</p

Design of anodes for IT SOFC: Effect of complex oxide promoters and pd on activity and stability in methane steam reforming of Ni/YSZ (ScSZ) cermets

Effect of fluorite-like or perovskite-like complex oxide promoters and Pd on the performance of Ni/8YSZ and Ni/ScSZ anode materials in CH4 steam reforming (SR) or selective oxidation (SO) by O-2 into syngas was studied. The spatial uniformity of dopants distribution in composites was controlled by TEM combined with EDX analysis, while the lattice oxygen mobility and reactivity were estimated by CH4 and H-2 temperature-programmed reduction (TPR). The oxide promoters suppress the coke deposition even at stoichiometric H2O/CH4 ratio, while doping by Pd ensures a good performance at moderate (similar to 550 degrees C) temperatures required for the Intermediate -Temperature Solid Oxide Fuel Cells (IT SOFC) operation.</p