Adhesive Performance of Sorghum Protein Extracted from Sorghum DDGS and Flour

Distillers dried grains with solubles (DDGS) is the main co-product from grain-based ethanol production. The objective of this research was to compare the adhesive performance of three types of sorghum proteins: acetic acid-extracted sorghum protein from DDGS (PI), aqueous ethanol-extracted sorghum protein from DDGS (PII) and acetic acid-extracted sorghum protein from sorghum flour (PF). Physicochemical properties including amino acid composition, and rheological, thermal and morphological properties also were characterized. Results showed that PI had the best adhesion performance in terms of dry, wet and soak adhesion strength, followed by PF and PII. The wet strength of PI at a concentration of 12% protein assembled at 150 °C was 3.15 MPa, compared to 2.17 MPa and 2.59 MPa for PII and PF, respectively. DSC thermograms indicated that the PF protein isolates contained higher levels of carbohydrates than PI and PII; such non-protein contaminants in the PF isolate could be the reason for its lower adhesion strength than PI. In addition, PI might have more hydrophobic amino acids aligned at the protein-wood interface than PII, which could explain the better water resistance of PI. The optimum sorghum protein concentration and pressing temperature for maximum adhesion strength was 12% and 150 °C. PI had a significantly higher wet strength (3.15 MPa) than unmodified soy protein (1.63 MPa for soy protein). The high percentage of hydrophobic amino acids in PI (57%) was likely a key factor in the increased water resistance of PI compared with soy protein (36% hydrophobic amino acids). These results indicated that sorghum protein has huge potential as an alternative to petroleum-based adhesives.     

Phosphorus use-efficiency of agriculture and food system in the US

The rapid increase in human mobilization of phosphorus has raised concerns on both its supply security and its impact on the environment. Increasing the efficiency of phosphorus use is an approach to mitigate the adverse impacts associated with phosphorus consumption. This study estimates the life-cycle phosphorus use-efficiency of the US food system. A framework for accounting phosphorus stocks and flows is developed, and the account was populated with data. A map of phosphorus stocks and flows around the US food system is drawn and phosphorus use-efficiency was calculated. The results show that only 15% of the total phosphorus extracted from nature for the provision of food is eventually ingested by humans and the rest is lost to the environment. Major losses occur during the livestock, meat and dairy production and crop cultivation stage, where about 66% of the total phosphorus extracted is lost to the environment. The results also show that other losses of phosphorus including household food waste, mining waste, and fertilizer manufacturing waste are not negligible, which constitute about 19% of the total phosphorus extracted for food purpose. A data quality assessment and sensitivity analysis was performed to identify data quality hotspots and to envisage effective measures to improving phosphorus use-efficiency. Improving yields of livestock and crop cultivation without additional phosphorus input and reducing household food waste are shown to be effective measures to improve life-cycle phosphorus use-efficiency. The results highlight the need of a concerted effort by all entities along the life-cycle for efficient use of phosphorus.     

Assessment of bisphenol A released from reusable plastic, aluminium and stainless steel water bottles

Bisphenol A (BPA) is a ubiquitous high volume industrial chemical that is an estrogen and an environmental endocrine disrupting chemical. Bisphenol A is used extensively in the production of consumer goods, polycarbonate plastics, epoxy resins and coatings used to line metallic food and beverage cans. There is great concern regarding the possible harmful effects from exposures that result from BPA leaching into foods and beverages from packaging or storage containers. The objective of this study was to independently assess whether BPA contamination of water was occurring from different types of reusable drinking bottles marketed as alternatives to BPA-containing polycarbonate plastics. Using a sensitive and quantitative BPA-specific competitive enzyme-linked immunosorbent assay we evaluated whether BPA migrated into water stored in polycarbonate or copolyester plastic bottles, and different lined or unlined metallic reusable water bottles. At room temperature the concentration of BPA migrating from polycarbonate bottles ranged from 0.2 to 0.3 mg L⁻¹. Under identical conditions BPA migration from aluminium bottles lined with epoxy-based resins was variable depending on manufacturer ranging from 0.08 to 1.9 mg L⁻¹. Boiling water significantly increased migration of BPA from the epoxy lined bottles. No detectable BPA contamination was observed in water stored in bottles made from Tritan™ copolyester plastic, uncoated stainless steel, or aluminium lined with EcoCare™. The results from this study demonstrate that when used according to manufacturers’ recommendations reusable water bottles constructed from “BPA-free” alternative materials are suitable for consumption of beverages free of BPA contamination.     

Modeling the Relations Between Flow Regime Components,Species Traits,and Spawning Success of Fishes in Warmwater Streams

Modifications to stream hydrologic regimes can have a profound influence on the dynamics of their fish populations. Using hierarchical linear models, we examined the relations between flow regime and young-of-year fish density using fish sampling and discharge data from three different warmwater streams in Illinois, Alabama, and Georgia. We used an information theoretic approach to evaluate the relative support for models describing hypothesized influences of five flow regime components representing: short-term high and low flows; short-term flow stability; and long-term mean flows and flow stability on fish reproductive success during fish spawning and rearing periods. We also evaluated the influence of ten fish species traits on fish reproductive success. Species traits included spawning duration, reproductive strategy, egg incubation rate, swimming locomotion morphology, general habitat preference, and food habits. Model selection results indicated that young-of-year fish density was positively related to short-term high flows during the spawning period and negatively related to flow variability during the rearing period. However, the effect of the flow regime components varied substantially among species, but was related to species traits. The effect of short-term high flows on the reproductive success was lower for species that broadcast their eggs during spawning. Species with cruiser swimming locomotion morphologies (e.g., Micropterus) also were more vulnerable to variable flows during the rearing period. Our models provide insight into the conditions and timing of flows that influence the reproductive success of warmwater stream fishes and may guide decisions related to stream regulation and management.     

Evolution of vehicle exhaust particles in the atmosphere

Aerosol mass spectrometer (AMS) measurements are used to characterize the evolution of exhaust particulate matter (PM) properties near and downwind of vehicle sources. The AMS provides time-resolved chemically speciated mass loadings and mass-weighted size distributions of nonrefractory PM smaller than 1 microm (NRPM1). Source measurements of aircraft PM show that black carbon particles inhibit nucleation by serving as condensation sinks for the volatile and semi-volatile exhaust gases. Real-world source measurements of ground vehicle PM are obtained by deploying an AMS aboard a mobile laboratory. Characteristic features of the exhaust PM chemical composition and size distribution are discussed. PM mass and number concentrations are used with above-background gas-phase carbon dioxide (CO2) concentrations to calculate on-road emission factors for individual vehicles. Highly variable ratios between particle number and mass concentrations are observed for individual vehicles. NRPM1 mass emission factors measured for on-road diesel vehicles are approximately 50% lower than those from dynamometer studies. Factor analysis of AMS data (FA-AMS) is applied for the first time to map variations in exhaust PM mass downwind of a highway. In this study, above-background vehicle PM concentrations are highest close to the highway and decrease by a factor of 2 by 200 m away from the highway. Comparison with the gas-phase CO2 concentrations indicates that these vehicle PM mass gradients are largely driven by dilution. Secondary aerosol species do not show a similar gradient in absolute mass concentrations; thus, their relative contribution to total ambient PM mass concentrations increases as a function of distance from the highway. FA-AMS of single particle and ensemble data at an urban receptor site shows that condensation of these secondary aerosol species onto vehicle exhaust particles results in spatial and temporal evolution of the size and composition of vehicle exhaust PM on urban and regional scales.     

Externalization of employment in a service environment: the role of organizational and customer identification

This study investigates the impact of employment externalization (in the form of limited‐term vs. permanent employment status) on customer‐oriented service behavior, and how identification processes may help to resolve the ‘paradox of externalization’ (i.e., organizations relying more on potentially disenfranchised employees to maintain strong connections with their customers). Survey data were obtained from 369 sales, service, and technical support personnel from the Canadian subsidiary of a large international service organization in the high technology sector. Organizational and customer identification fully mediate the relationship between employment status and customer‐oriented service behavior. Additionally, the perceived external image of the organization and the visibility of one's affiliation with the organization moderate the relationships between employment status and organizational and customer identification. Copyright © 2007 John Wiley & Sons, Ltd.     

Cell preparation methods influence Escherichia coli D21g surface chemistry and transport in saturated sand

The effect of cell preparation methods on the surface chemistry and retention of Escherichia coli D21 g was investigated over a range of ionic strength conditions. The cell preparation methods that were considered included filtration and centrifugation (at various speeds and for different durations). For a given ionic strength condition, it was found that cells prepared by filtration were more negatively charged and hydrophobic than cells prepared by centrifugation. Increasing the centrifugation speed (force imposed) or duration produced cells with a higher zeta potential (less negative) and a lower hydrophobicity. Column transport experiments for E. coli D21 g were also conducted with ultra pure quartz sand and the same solution chemistries. The first-order retention rate coefficient for E. coli D21 g increased with increasing speed and duration of centrifugation, and was lowest in the case of filtered cells. Moreover, the influence of cell preparation method was more pronounced in lower ionic strength solutions.     

A Systematic Review of Wild Burro Grazing Effects on Mojave Desert Vegetation,USA

Wild burros (Equus asinus), protected by the 1971 Wild Free-Roaming Horse and Burro Act on some federal lands but exotic animals many ecologists and resource mangers view as damaging to native ecosystems, represent one of the most contentious environmental management problems in American Southwest arid lands. This review synthesizes the scattered literature about burro effects on plant communities of the Mojave Desert, a center of burro management contentions. I classified 24 documents meeting selection criteria for this review into five categories of research: (i) diet analyses directly determining which plant species burros consume, (ii) utilization studies of individual species, (iii) control-impact comparisons, (iv) exclosure studies, and (v) forage analyses examining chemical characteristics of forage plants. Ten diet studies recorded 175 total species that burros consumed. However, these studies and two exclosure studies suggested that burros preferentially eat graminoid and forb groups over shrubs. One study in Death Valley National Park, for example, found that Achnatherum hymenoides (Indian ricegrass) was 11 times more abundant in burro diets than expected based on its availability. Utilization studies revealed that burros also exhibit preferences within the shrub group. Eighty-three percent of reviewed documents were produced in a 12-year period, from 1972 to 1983, with the most recent document produced in 1988. Because burros remain abundant on many federal lands and grazing may interact with other management concerns (e.g., desert wildfires fueled by exotic grasses), rejuvenating grazing research to better understand both past and present burro effects could help guide revegetation and grazing management scenarios.     

Toxicity and metal speciation characterisation of waste water from an abandoned gold mine in tropical northern Australia

The decommissioned Mount Todd gold mine, located in the wet-dry tropics of northern Australia, consists of a large waste water inventory and an acid rock drainage problem, which has the potential to impact upon freshwater ecosystems of the Edith River catchment. The toxicity of retention pond 1 (RP1) water was determined using six local freshwater species (duckweed, alga, cladoceran, snail, hydra and a fish). RP1 water was very toxic to all species, with the percentage dilution of RP1 water inhibiting 10% of organism response (IC(10)), or lethal to 5% of individuals (LC(5)), ranging from 0.007 to 0.088%. The percentage dilution of RP1 water inhibiting 50% of organism response (IC(50)), or lethal to 50% of individuals (LC(50)), ranged from 0.051% to 0.58%. Based on chemical analyses and geochemical speciation modelling of the test waters, Cu, Zn and Al were the most likely toxic components at acidic dilutions (i.e. 1%), while Cu and Zn were the most likely toxic components at 0.1% RP1 water, where pH was 6.5. Species sensitivity distributions (SSDs) were used to predict dilutions of RP1 water that would protect or unacceptably affect the downstream aquatic ecosystems. A dilution ratio of 1 part RP1 water to 20000 parts Edith River water (0.005% RP1 water) was calculated to be required for the protection of at least 95% of species. This information can be used in conjunction with field chemical and biological data to better predict the ecological risks of RP1 waste water downstream of the Mount Todd mine.     

Influence of fipronil compounds and rice-cultivation land-use intensity on macroinvertebrate communities in streams of southwestern Louisiana, USA

Laboratory tests of fipronil and its degradation products have revealed acute lethal toxicity at very low concentrations (LC50) of <0.5 microg/L to selected aquatic macroinvertebrates. In streams draining basins with intensive rice cultivation in southwestern Louisiana, USA, concentrations of fipronil compounds were an order of magnitude larger than the LC50. The abundance (rho=-0.64; p=0.015) and taxa richness (r2=0.515, p<0.005) of macroinvertebrate communities declined significantly with increases in concentrations of fipronil compounds and rice-cultivation land-use intensity. Macroinvertebrate community tolerance scores increased linearly (r2=0.442, p<0.005) with increases in the percentage of rice cultivation in the basins, indicating increasingly degraded stream conditions. Similarly, macroinvertebrate community-tolerance scores increased rapidly as fipronil concentrations approached about 1 microg/L. Pesticide toxicity index determinations indicated that aquatic macroinvertebrates respond to a gradient of fipronil compounds in water although stream size and habitat cannot be ruled out as contributing influences.