Pharmacological Perspectives on the Detoxification of Plant Secondary Metabolites: Implications for Ingestive Behavior of Herbivores

Plant secondary metabolites (PSMs) are a major constraint to the ingestion of food by folivorous and browsing herbivores. Understanding the way in which mammalian detoxification pathways are adapted to deal with PSMs is crucial to understanding how PSMs influence ingestive behavior of herbivores and hence their fitness and the impact that they have on vegetation. Pharmacological concepts can provide insights into the relationship between the absorption and metabolic fate of PSMs and ingestive behavior. Lipophilic PSMs will be absorbed into the bloodstream and must be removed fast enough to prevent their accumulation to toxic levels. Elimination depends on their metabolism, usually by cytochrome P450 enzymes, to more polar metabolites that can be excreted by the kidney. The concentration of PSM in blood (C) is a better measure of exposure to a toxin compared to the amount ingested because there can be great variability in the rate and degree of absorption from the gut. C rises and falls depending on the relative rates of absorption and elimination. These rates depend in part on metabolic and transport processes that are saturable and liable to inhibition and induction by PSMs, indicating that complex interactions are likely. Herbivores can use diet choice and the rate and amount of PSM consumption to prevent C from reaching a critical level that produces significant adverse effects.     

Fabrication of Thin-Film SrCe0.9Eu0.1O3−δ Hydrogen Separation Membranes on Ni–SrCeO3 Porous Tubular Supports

SrCe_0.9Eu_0.1O_3−δ thin-film (∼30 μm) tubular hydrogen separation membranes were developed in order to obtain high hydrogen fluxes. Fifteen centimeters long, one end closed, NiO–SrCeO₃ tubular supports were fabricated by tape casting, followed by rolling the green tape on a circular rod. SrCe_0.9Eu_0.1O_3−δ powders were prepared by the citrate process and coated on partially sintered NiO–SrCeO₃ tubular supports. Leakage-free hydrogen membrane cells were obtained by adjusting the presintering and final sintering temperatures to reduce the difference of linear shrinkage rates between SrCe_0.9Eu_0.1O_3−δ thin films and NiO–SrCeO₃ supports. A hydrogen flux of 2.2 cm³/min was obtained for the SrCe_0.9Eu_0.1O_3−δ on Ni–SrCeO₃ tubular hydrogen separation membranes at 900°C using 25% H₂ balanced with Ar and 3% H₂O as the feed gas and He as the sweep gas. Thus, a 40% single pass yield of pure H₂ was achieved with this membrane.     

X-ray diffraction studies of electrochemical graphite intercalation compounds of ionic liquids

Electrochemical intercalation studies are used to characterize a series of ionic liquids composed of a variety of cationic and anionic species. Electrochemically, the ionic liquids are characterized by cyclic voltammograms and charge–discharge experiments for the intercalation and de-intercalation of the various cationic and anionic species into graphite. X-ray structure analysis is also performed to determine the relationship between the electrochemical behaviour of the ionic liquids, and the formation of intercalated graphitic compounds. Two different types of imidazolium cations are studied, specifically the di- and trisubstituted imidazolium. These cations are paired with the following anions: tetrafluoroborate, hexafluorophosphate, bis(trifluoromethanesulfonyl)imide, bis(perfluoroethanesulfonyl)imide, nitrate and hydrogen sulfate. Results indicate stronger intercalation chemistry for the trisubstituted imidazoliums, correlating with the greater charge–discharge efficiencies found for these types of ionic liquids. Many of the anions exhibit very poor charge–discharge efficiencies, correlating to very poorly formed graphite intercalates. The exception to this is the hydrogen sulfate intercalate, which had low charge–discharge efficiencies but formed a well defined graphite intercalate. Only the imide based anions exhibited both high charge–discharge efficiencies and the formation of a clearly defined graphite intercalate.     

Effect of fire retardants on mechanical properties of a green bio-epoxy composite

To improve fire retardant behavior of bio-epoxy resin, composites were prepared with three fire retardants (FRs); ammonium polyphosphate, aluminum trihydrate, and magnesium hydroxide. Fractured surfaces of prepared composites were observed with the scanning electron microscope (SEM). Tensile strength and Charpy toughness were evaluated and analyzed statistically using analysis of variance (ANOVA). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to determine the thermal stability. SEM analysis results revealed fractured surfaces were altered with addition of FRs. Adding FRs can be regarded as a decrease in tensile strength and toughness complemented by improved stiffness. ANOVA analysis showed FR/bio-resin composites have a statistically significant loss in tensile strength, stiffness, elongation, and Charpy toughness. The DSC results showed the glass transition temperature was not affected significantly by adding FRs and ranged from 66 to 69 °C. TGA showed the initial, midway, and maximum decomposition temperatures for composites and their ability to form improved ash yields compared to pure resin. Aluminum trihydrate and Mg(OH)₂ had higher T₅₀ suggesting an increase in thermal stability compared to pure bio-epoxy. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47398.     

Shape memory polyurethane-urea foams with improved toughness

Current vascular aneurysm treatments often require either highly invasive strategy to surgically occlude an aneurysm or endovascular occlusion via metal coils. While endovascular coils are safer, they have limited efficacy. Endovascular coils that are integrated with shape memory polymer (SMP) foams have the potential to improve occlusion and reduce coil risks; however, the mechanical performance and limited homogeneity of SMP foams can hinder their effective use. To address this issue, SMP foams are synthesized using the monomer diethanolamine (DEA) in place of triethanolamine (TEA) to provide improved mechanical properties for medical device applications. Mechanical testing and micro-fracture analysis were performed on DEA and TEA foams. DEA foams show improved toughness and reduced micro-fractures compared to the control. This work presents the utility of DEA in SMP synthesis to enable the potential production of safer aneurysm treatment. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47268.     

Near-field commercial aircraft contribution to nitrogen oxides by engine, aircraft type, and airline by individual plume sampling

Nitrogen oxides (NOx) concentrations were measured in individual plumes from aircraft departing on the northern runway at Heathrow Airport in west London. Over a period of four weeks 5618 individual plumes were sampled by a chemiluminescence monitor located 180 m from the runway. Results were processed and matched with detailed aircraft movement and aircraft engine data using chromatographic techniques. Peak concentrations associated with 29 commonly used engines were calculated and found to have a good relationship with N0x emissions taken from the International Civil Aviation Organization (ICAO) databank. However, it is found that engines with higher reported NOx emissions result in proportionately lower NOx concentrations than engines with lower emissions. We show that it is likely that aircraft operational factors such as takeoff weight and aircraftthrust setting have a measurable and important effect on concentrations of N0x. For example, NOx concentrations can differ by up to 41% for aircraft using the same airframe and engine type, while those due to the same engine type in different airframes can differ by 28%. These differences are as great as, if not greater than, the reported differences in NOx emissions between different engine manufacturers for engines used on the same airframe.     

Compact spectrum splitting photovoltaic module with high efficiency

We have designed, fabricated, and tested a small, integrated photovoltaic module comprised of two separately‐contacted, high efficiency, multijunction solar cells and non‐imaging optics that both concentrate and spectrally split the incoming light. This hybrid design allows us to individually optimize the tandem cells and optical elements. The system has a measured module efficiency, including optical and packaging losses but not power combination losses, of 38.5 ± 1.9% under the AM1.5 direct terrestrial spectrum. The internal optics concentrate the light by a factor of approximately 20. We find excellent agreement between the modeled and measured performance. This is the highest confirmed conversion efficiency demonstrated for a photovoltaic module. Copyright © 2010 John Wiley & Sons, Ltd.     

Politicizing food security governance through participation: opportunities and opposition

Since the 2007/08 food price crisis there has been a proliferation of multi-stakeholder processes (MSPs) devoted to bringing diverse perspectives together to inform and improve food security policy. While much of the literature highlights the positive contributions to be gained from an opening-up of traditionally state-led processes, there is a strong critique emerging to show that, in many instances, MSPs have de-politicizing effects. In this paper, we scrutinize MSPs in relation to de-politicization. We argue that re-building sustainable and just food systems requires alternative visions that can best be made visible through politicized policy processes. Focusing on three key conditions of politicization, we examine the UN Committee on World Food Security as a MSP where we see a process of politicization playing out through the endorsement of the ‘most-affected’ principle, which is in turn being actively contested by traditionally powerful actors. We conclude that there is a need to implement and reinforce mechanisms that deliberately politicize participation in MSPs, notably by clearly distinguishing between states and other stakeholders, as well as between categories of non-state actors.     

Oxygenated VOCs,aqueous chemistry,and potential impacts on residential indoor air composition

Dampness affects a substantial percentage of homes and is associated with increased risk of respiratory ailments; yet, the effects of dampness on indoor chemistry are largely unknown. We hypothesize that the presence of water‐soluble gases and their aqueous processing alters the chemical composition of indoor air and thereby affects inhalation and dermal exposures in damp homes. Herein, we use the existing literature and new measurements to examine the plausibility of this hypothesis, summarize existing evidence, and identify key knowledge gaps. While measurements of indoor volatile organic compounds (VOCs) are abundant, measurements of water‐soluble organic gases (WSOGs) are not. We found that concentrations of total WSOGs were, on average, 15 times higher inside homes than immediately outside (N = 13). We provide insights into WSOG compounds likely to be present indoors using peer‐reviewed literature and insights from atmospheric chemistry. Finally, we discuss types of aqueous chemistry that may occur on indoor surfaces and speculate how this chemistry could affect indoor exposures. Liquid water quantities, identities of water‐soluble compounds, the dominant chemistry, and fate of aqueous products are poorly understood. These limitations hamper our ability to determine the effects of aqueous indoor chemistry on dermal and inhalation exposures in damp homes.