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Lead (Pb) is a toxic element which is released as a result of anthropogenic activities, and Pb stable isotope ratios provide a means to distinguish sources and transport pathways in receiving environments. In this study, isotopes of bioaccumulated Pb (204Pb, 206Pb, 207Pb, 208Pb) were examined for diverse terrestrial and aquatic biota from three areas in western Canada: (a) otter, marten, gulls, terns, and wood frogs in the Alberta Oil Sands Region (AOSR), (b) fish, plankton, and gulls of Great Slave Lake (Yellowknife, Northwest Territories), and (c) wolverine from the Yukon. Aquatic and terrestrial biota from different habitats and a broad geographic area showed a remarkable similarity in their Pb isotope composition (grand mean ± 1 standard deviation: 206Pb/207Pb = 1.189 ± 0.007, 208Pb/207Pb = 2.435 ± 0.009, n = 116). Comparisons with Pb isotope ratios of local sources and environmental receptors showed that values in biota were most similar to those of atmospheric Pb, either measured in local aerosols influenced by industrial activities in the AOSR or in lichens (an aerosol proxy) near Yellowknife and in the Yukon. Biotic Pb isotope ratios were different from those of local geogenic Pb. Although the Pb isotope measurements could not unambiguously identify the specific anthropogenic sources of atmospheric Pb in biota, initial evidence points to the importance of fossil fuels currently used in transportation and power generation. Further research should characterize bioavailable chemical species of Pb in aerosols and important emission sources in western Canada. [Display omitted] • Pb isotope ratios were strikingly similar in diverse animals from western Canada. • The bioaccumulated Pb originated primarily from atmospheric aerosols. • Natural geogenic sources contributed little to bioaccumulated Pb. • Pb isotopes suggest aerosol Pb is highly bioavailable. • Fossil fuels may be important sources of bioavailable Pb to fish and wildlife. [ABSTRACT FROM AUTHOR]

This paper proposes a new gravitational search algorithm to solve the unit commitment (UC) problem, which is integrated binary gravitational search algorithm (BGSA) with the Lambda-iteration method. The proposed method is enhanced by priority list based on the unit characteristics and heuristic search strategies to repair the spinning reserve and minimum up/down time constraints. Furthermore, local mutation strategies are applied to improve the performance of BGSA. The implementation of the proposed method for UC problem consists of three stages. Firstly, the BGSA based on priority list is applied for solution unit scheduling when neglecting minimum up/down time constraints. Secondly, heuristic search strategies are used to handle minimum up/down time constraints and decommit excess spinning reserve units. Thirdly, local mutation strategies are raised to avoid premature convergence of the algorithm and prevent it from trapping into local optima. Finally, Lambda-iteration method is adopted to solve economic load dispatch based on the obtained unit schedule. The feasibility and effectiveness of the proposed method is verified by the systems with the number of units in the range of 10–100 and the results are compared with those of other methods reported in literatures. The results clearly show that the proposed method gives better quality solutions than other methods. [ABSTRACT FROM AUTHOR]

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF superfamily and plays multifunctional roles in the immune system. In the present study, a homolog of TRAIL from the Mongolian horse (named ecTRAIL) was identified and characterized. The 870-bp open reading frame encodes a polypeptide of 289 amino acid residues with a predicted molecular weight of 33.47 kDa and p I of 8.47. The genomic structure of ecTRAIL shares a five-exon/six-intron arrangement similar to its orthologs. Multiple alignments show that ecTRAIL is a type II transmembrane protein with a typical transmembrane region, three conserved cysteine residues (Cys56, Cys77, Cys238) and a TNF family signature sequence ([LV]-x-[LIVM]-x(3)-G-[LIVMF]-Y-[LIVMFY](2)-x(2)-[QEKHL]-[LIVMGT]-x-[LIVMFY]). Three-dimensional structure prediction based on the same template revealed that the positional arrangement of the key amino acid residues, Cys238 and Cys230 in ecTRAIL and human TRAIL, respectively, is significantly conserved. Evolutionary analysis suggests that ecTRAIL is most closely related to its ortholog from pigs, with an identity of 83.99%. The solubilizing small ubiquitin-related modifier (SUMO) tag fused recombinant protein SUMO-ecsTRAIL was successfully expressed in E. coli and exhibited binding activity and cytotoxicity to HeLa cells in a cross-species manner in vitro . These results provide a better understanding of TRAILs in mammals and indicate that ecTRAIL may play an important role in the immune response in horses. [ABSTRACT FROM AUTHOR]