Volatiles from Intact and Lygus-Damaged Erigeron annuus (L.) Pers. are Highly Attractive to Ovipositing Lygus and its Parasitoid Peristenus relictus Ruthe

Trap cropping and biological control can provide a sustainable means of controlling insect pests. Insects in the genus Lygus (Hemiptera: Miridae) are major pests on cotton and horticultural crops throughout the United States, and pesticide resistance within Lygus populations necessitates more sustainable long-term management techniques. Here, we explore behavioral responses of Lygus bugs (L. rubrosignatus Knight) and an introduced parasitoid, Peristenus relictus (Hymenoptera: Braconidae), to a common field edge plant, Erigeron annuus, which has the potential to serve as a trap host. Erigeron annuus is attractive to Lygus in the field, with Lygus preferentially moving to Erigeron patches compared to more abundant cotton plants. To determine the role of odor cues in mediating this attraction, we collected volatiles from E. annuus with and without Lygus damage, and then tested the attractiveness of these volatiles vs. those of cotton to Lygus females and female P. relictus wasps using Y-tube and wind tunnel bioassays. We found that undamaged E. annuus emits high concentrations of a complex volatile blend (60+ compounds), with novel compounds induced and constitutive compounds up-regulated in response to damage. Additionally, both female Lygus bugs and female P. relictus wasps are highly attracted to E. annuus volatiles over those of cotton in almost every combination of damage treatments. Our results suggest that Erigeron annuus would be an effective trap plant to control Lygus in cotton, since it is highly attractive to both the pest and its natural enemy.     

Bipolar resistive switching in p-type Co3O4 nanosheets prepared by electrochemical deposition

Metal oxide nanosheets have potential applications in novel nanoelectronics as nanocrystal building blocks. In this work, the devices with a structure of Au/p-type Co₃O₄ nanosheets/indium tin oxide/glass having bipolar resistive switching characteristics were successfully fabricated. The experimental results demonstrate that the device have stable high/low resistance ratio that is greater than 25, endurance performance more than 200 cycles, and data retention more than 10,000 s. Such a superior performance of the as-fabricated device could be explained by the bulk film and Co₃O₄/indium tin oxide glass substrate interface effect.     

Conversion of Nitrogen to Protein and Amino Acids in Wild Fruits

Protein content of plant tissues is usually estimated by multiplying total nitrogen by a conversion factor of 6.25. This technique assumes that all nitrogen originates from protein. When applied to fruit pulp, it overestimates protein content because pulp typically contains free amino acids and many nitrogenous secondary metabolites. At issue is the extent of error and, consequently, what the conversion factor between nitrogen and protein should be. We calculated a conversion factor based on pulp samples from 18 species collected in the southeastern United States. We also report a new and simple method of estimating protein and free amino acids in fruit pulp. Because previous studies have found high variation in protein and secondary metabolite content among fruit species, use of a single conversion factor for all species will generate error. In an attempt to reduce such error, we calculated protein contents and conversion factors separately for two common fruit types: lipid-rich/carbohydrate-poor and lipid-poor/carbohydrate-rich. We found no difference between these types of fruit and hence combined results in calculating an average conversion factor of 5.64. Use of an accurate conversion factor is important in estimating protein consumption by wild animals and in formulating diets of captive animals. It can also reveal whether loss of body mass in captive animals on fruit diets is due to insufficient protein consumption, secondary metabolite toxicity, or an imbalance of amino acids.     

CONCENTRATION POLARIZATION ANALYSIS AT THE ENTRANCE REGION OF A FLAT SHEET PERVAPORATION MODULE FOR VOC REMOVAL

Concentration polarization is a phenomenon that is inherent in all membrane separation processes, which is difficult if not impossible to measure experimentally. Concentration polarization in a pervaporation module causes flux decline and is therefore an important issue in predicting the performance of the membrane unit for evaluation and optimization. Short-form (small L/D ratio) membrane configurations, commonly used for membrane evaluations or certain material separations, compound the complexity of process modeling that addresses concentration polarization since a substantial portion of the membrane flow channel would be considered as an “entrance region” based on the flow profile that is not fully developed. This article employed the classic boundary layer theory, combined with mass transfer phenomena in a pervaporation process that is used in volatile organic compound (VOC) removal from contaminated water sources, to theoretically analyze the concentration polarization severity in the entrance region of a flat sheet membrane module.     

Biochemical Functions of Geophagy in Parrots: Detoxification of Dietary Toxins and Cytoprotective Effects

This study tests hypotheses on the biochemical functions of geophagy in parrots: mechanical enhancement of digestion, acid buffering capacity, mineral supplementation, adsorption of dietary toxins, and gastrointestinal cytoprotection. Parrots showed clear preferences for specific soil horizons. Comparisons of preferred and nonpreferred soils from several sites suggest that soils have little ability to enhance grinding and no measurable ability to buffer gastric pH. Soils offered insignificant mineral supplementation since most minerals occurred at similar levels in samples regardless of preference, and the minerals were generally more plentiful in the birds' diets. Sodium was available in moderate levels at some sites (>1000 ppm), but was well below sodium detection thresholds of parrots. X-ray diffraction, cation exchange capacity, and in vitro adsorptive trials showed that the preferred soils are capable of exchanging substantial quantities of cations and are capable of adsorbing low-molecular-weight secondary compounds. In captive Amazona parrots, orally administered clay reduced the bioavailability of the alkaloid quinidine by roughly 60%, demonstrating that in vivo adsorption of potentially toxic compounds may be a biologically important function of geophagy. Labeled clay remained in the lower gastrointestinal tract of captive parrots for >12 hr, which along with high adsorptive capacities, further suggests a potential role in protecting the gastrointestinal lining from various biological and chemical insults. Detoxification and cytoprotection are the most likely functions of geophagy for parrots and herbivores with similar ecologies. Given the variety of chemically defended seeds consumed by these herbivores, geophagy likely protects consumers from dietary toxins, allowing increased diet breadth and/or enhancing digestibility.     

Regulating the geological sequestration of CO2

Governments worldwide should provide incentives for initial large-scale GS projects to help build the knowledge base for a mature, internationally harmonized GS regulatory framework. Health, safety, and environmental risks of these early projects can be managed through modifications of existing regulations in the EU, Australia, Canada, and the U.S. An institutional mechanism, such as the proposed Federal Carbon Sequestration Commission in the U.S., should gather data from these early projects and combine them with factors such as GS industrial organization and climate regime requirements to create an efficient and adaptive regulatory framework suited to large-scale deployment. Mechanisms to structure long-term liability and fund long-term postclosure care must be developed, most likely at the national level, to equitably balance the risks and benefits of this important climate change mitigation technology. We need to do this right. During the initial field experiences, a single major accident, resulting from inadequate regulatory oversight, anywhere in the world, could seriously endanger the future viability of GS. That, in turn, could make it next to impossible to achieve the needed dramatic global reductions in CO2 emissions over the next several decades. We also need to do it quickly. Emissions are going up, the climate is changing, and impacts are growing. The need for safe and effective CO2 capture with deep GS is urgent.     

A study of stabilization of P3HT/PCBM organic solar cells by photochemical active TiOx layer

We describe a study of the stabilization behavior of P3HT/PCBM organic solar cells under air and UV irradiation using a 20 nm thin TiO_x protection layer made by partial hydrolysis of a Ti-alkoxide and spin coating in air. Data on the degradation of solar cell performance under air and under UV exposure are presented indicating that significant improvements are observed with TiO_x layer protection. The protection mechanism has been investigated by transmission IR and UV spectroscopy and by ESR spectroscopy. The results of this study suggest how sol-gel derived TiO_x films containing organic functionalities serve as effective passivation films for protection from oxygen when excited by photons, where the photooxidation of the bound organic moieties causes oxygen gas scavenging.     

NMR spectroscopic and thermodynamic studies of the etherate and the α, α′, and γ phases of AlH3

Aluminum hydride (alane; AlH₃) has been identified as a leading hydrogen storage material by the US Department of Energy. With a high gravimetric hydrogen capacity of 10.1 wt.%, and a hydrogen density of 1.48 g/cm³, AlH₃ decomposes cleanly to its elements above 60 °C with no side reactions. This study explores in detail the thermodynamic and spectroscopic properties of AlH₃; in particular the α, α′ and γ polymorphs, of which α′-AlH₃ is reported for the first time, free from traces of other polymorphs or side products. Thermal analysis of α-, α′-, and γ-AlH₃ has been conducted, using DSC and TGA methods, and the results obtained compared with each other and with literature data. All three polymorphs were investigated by ¹H MAS-NMR spectroscopy for the first time, and their ²⁷Al MAS-NMR spectra were also measured and compared with literature values. AlH₃·nEt₂O has also been studied by ¹H and ²⁷Al MAS-NMR spectroscopy and DSC and TGA methods, and an accurate decomposition pathway has been established for this adduct.     

Atmospheric flows of semi-volatile organic pollutants to the Great Lakes estimated by the United States' Integrated Atmospheric Deposition and Canada's Great Lakes Basin Monitoring and Surveillance Networks

We calculated the wet and dry deposition, vapor absorption, and volatilization flows (in kg/yr) of seven polychlorinated biphenyls (PCBs), nine organochlorine pesticides, and two polycyclic aromatic hydrocarbons (PAHs) into and out of the Great Lakes during 2010–2015 (inclusive). Particle, vapor, and precipitation concentrations from five rural and remote stations (one site on each lake) and two urban sites, operated by the United States and Canada, were used for the flow calculations. Output from the water to the air was the most important process for PCBs, chlordanes, and p,p′-DDE. The flows of endosulfan, p,p′-DDT, and phenanthrene were dominated by vapor absorption from the air to the water. The flow of benzo[a]pyrene was controlled by wet and dry deposition to the water. The flows of the hexachlorocyclohexanes (HCHs) into and out of the lakes were about equal, indicating air-water equilibrium for these compounds. Among the lakes, Lakes Superior and Erie had the highest input and output flows. The input and output flows for the five lakes were decreasing with halving times of 1–10 years and 10–40 years, respectively. Most chemicals had seasonal variations in their flows, with maximum inputs in the summer and maximum outputs in the fall. The flows of PCBs and PAHs into Lakes Michigan and Erie were associated with Chicago and Cleveland, respectively. Combining our data with previous data over the period 1992–2015, we estimated that the input flows of most of these chemicals have significantly decreased, but the output flows do not show consistent trends.     

Anaerobic methane oxidation and aerobic methane production in an east African great lake (Lake Kivu)

We investigated CH₄ oxidation in the water column of Lake Kivu, a deep meromictic tropical lake with CH₄-rich anoxic deep waters. Depth profiles of dissolved gases (CH₄ and N₂O) and a diversity of potential electron acceptors for anaerobic CH₄ oxidation (NO₃^?, SO₄^2?, Fe and Mn oxides) were determined during six field campaigns between June 2011 and August 2014. Denitrification measurements based on stable isotope labelling experiments were performed twice. In addition, we quantified aerobic and anaerobic CH₄ oxidation, NO₃^? and SO₄^2? consumption rates, with and without the presence of an inhibitor of SO₄^2?-reducing bacteria activity. Aerobic CH₄ production was also measured in parallel incubations with the addition of an inhibitor of aerobic CH₄ oxidation. The maximum aerobic and anaerobic CH₄ oxidation rates were estimated to be 27?±?2 and 16?±?8?μmol/L/d, respectively. We observed a difference in the relative importance of aerobic and anaerobic CH₄ oxidation during the rainy and the dry season, with a greater role for aerobic oxidation during the dry season. Lower anaerobic CH₄ oxidation rates were measured in presence of molybdate in half of the measurements, suggesting the occurrence of linkage between SO₄^2? reduction and anaerobic CH₄ oxidation. NO₃^? consumption and dissolved Mn production rates were never high enough to sustain the measured anaerobic CH₄ oxidation, reinforcing the idea of a coupling between SO₄^2? reduction and CH₄ oxidation in the anoxic waters of Lake Kivu. Finally, significant rates (up to 0.37?μmol/L/d) of pelagic CH₄ production were also measured in oxygenated waters.