76 research outputs found

    Determination of HBCD, PBDEs and MeO-BDEs in California sea lions (Zalophus californianus) stranded between 1993 and 2003

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    Author Posting. © Elsevier B.V., 2006. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Marine Pollution Bulletin 52 (2006): 522-531, doi:10.1016/j.marpolbul.2005.09.045.Blubber samples from male California sea lions (Zalphophus californianus) stranded between 1993 and 2003 were analyzed for 27 polybrominated diphenyl ether (PBDE) congeners, three isomers of hexabromocyclododecane (HBCD) and 14 methoxylated polybrominated diphenyl ether (MeO-BDE) congeners. Total PBDEs ranged from 450 ng/g to 4740 ng/g wet mass and total HBCD ranged from <0.3 ng/g to 12 ng/g wet mass. The concentration of HBCD increased from 0.7 ng/g to12.0 ng/g wet mass in sea lion blubber between 1993 and 2003. However, no significant temporal trend was observed for any of the other brominated compounds over this ten year period. Only one of the 14 MeO-BDE congeners was detected in the blubber samples, 6-methoxy- 2,2’,4,4’-tetrabromodiphenyl ether (6-MeO-BDE 47), and concentrations ranged from <0.2 ng/g to 12 ng/g wet mass. A bromo-, chloro- heterocyclic compound, 1,1’-dimethyl-tetrabromo-dichloro-2,2’-bipyrrole (DBP-Br4Cl2), previously reported in marine species along the Pacific coast, was also identified in the sea lion blubber. DBP-Br4Cl2 ranged from 44 ng/g wet mass to 660 ng/g wet mass and was present at concentrations rivaling the dominant PBDE congener, BDE 47 (2,2’,4,4’-tetrabromodiphenyl ether). Concentrations of DBP-Br4Cl2 were positively correlated with 6-MeO-BDE 47 (r= 0.7; p<0.05). Both of these compounds have been identified in marine algae and sponges, and studies suggest they are both produced from natural sources. This study demonstrates that brominated compounds from both anthropogenic and biogenic sources can accumulate to similar levels in marine mammals. In addition, HBCD concentrations appear to be increasing in California sea lion populations, whereas PBDE concentrations, between 1993 and 2003, were highly variable

    Multi-site assessment of the precision and reproducibility of multiple reaction monitoring–based measurements of proteins in plasma

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    Verification of candidate biomarkers relies upon specific, quantitative assays optimized for selective detection of target proteins, and is increasingly viewed as a critical step in the discovery pipeline that bridges unbiased biomarker discovery to preclinical validation. Although individual laboratories have demonstrated that multiple reaction monitoring (MRM) coupled with isotope dilution mass spectrometry can quantify candidate protein biomarkers in plasma, reproducibility and transferability of these assays between laboratories have not been demonstrated. We describe a multilaboratory study to assess reproducibility, recovery, linear dynamic range and limits of detection and quantification of multiplexed, MRM-based assays, conducted by NCI-CPTAC. Using common materials and standardized protocols, we demonstrate that these assays can be highly reproducible within and across laboratories and instrument platforms, and are sensitive to low µg/ml protein concentrations in unfractionated plasma. We provide data and benchmarks against which individual laboratories can compare their performance and evaluate new technologies for biomarker verification in plasma

    Integration of agricultural and energy system models for biofuel assessment

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    This paper presents a coupled modeling framework to capture the dynamic linkages between agricultural and energy markets that have been enhanced through the expansion of biofuel production, as well as the environmental impacts resulting from this expansion. The framework incorporates the interactions between agricultural and energy markets at the macro-level, and an assessment of production practices and environmental impacts at the micro (field)-level. For macro-level analysis, we use two existing modeling frameworks: the CARD U.S. agricultural markets model and the MARKAL energy systems model. The integrated modeling of agricultural and energy markets will be useful in analyzing a range of scenarios regarding the role of biomass feedstocks from the agricultural sector in an expanding market for biomass-based fuels and energy. Moreover, by linking the macro-level analysis to the micro-scale (field-level) analysis, we can represent shifts in farming practices, average productivity, and costs of production, as well as the environmental consequences of farmers' decisions resulting from the expansion of biomass feedstock production.This article is published as Elobeid, Amani, Simla Tokgoz, Rebecca Dodder, Tim Johnson, Ozge Kaplan, Lyubov Kurkalova, and Silvia Secchi. "Integration of agricultural and energy system models for biofuel assessment." Environmental Modelling & Software 48 (2013): 1-16. doi:10.1016/j.envsoft.2013.05.007. Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted

    Integration of agricultural and energy system models for biofuel assessment

    No full text
    This paper presents a coupled modeling framework to capture the dynamic linkages between agricultural and energy markets that have been enhanced through the expansion of biofuel production, as well as the environmental impacts resulting from this expansion. The framework incorporates the interactions between agricultural and energy markets at the macro-level, and an assessment of production practices and environmental impacts at the micro (field)-level. For macro-level analysis, we use two existing modeling frameworks: the CARD U.S. agricultural markets model and the MARKAL energy systems model. The integrated modeling of agricultural and energy markets will be useful in analyzing a range of scenarios regarding the role of biomass feedstocks from the agricultural sector in an expanding market for biomass-based fuels and energy. Moreover, by linking the macro-level analysis to the micro-scale (field-level) analysis, we can represent shifts in farming practices, average productivity, and costs of production, as well as the environmental consequences of farmers' decisions resulting from the expansion of biomass feedstock production.This article is published as Elobeid, Amani, Simla Tokgoz, Rebecca Dodder, Tim Johnson, Ozge Kaplan, Lyubov Kurkalova, and Silvia Secchi. "Integration of agricultural and energy system models for biofuel assessment." Environmental Modelling & Software 48 (2013): 1-16. doi:10.1016/j.envsoft.2013.05.007. Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted

    Exploring a United States Maize Cellulose Biofuel Scenario Using an Integrated Energy and Agricultural Markets Solution Approach

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    Biofuel feedstock production in the United States (US) is an emergent environmental nutrient management issue, whose exploration can benefit from a multi-scale and multimedia systems modeling approach that explicitly addresses diverging stakeholder interests. In the present analysis, energy and agricultural markets models and a hybrid process-based agricultural production model are integrated to explore the potential environmental consequences of increased biofuel production from maize grain and stover feedstocks. Yield and cropland reallocation projections are simulated for 20 agricultural crops at a 12km grid resolution across the continental United States. Our results are presented across multiple, spatially expanding domains, and our results for the Upper Mississippi River Basin (UMRB) are compared to previous studies. Our analysis highlights the critical continuing role of agricultural and crop science to provide physically plausible estimates and physical process drivers of yield increases, and suggests that while the UMRB is the target of the greatest agricultural changes under our scenarios, its response does not necessarily reflect the interests of a broad stakeholder community.This article is published as Cooter EJ, Dodder R, Bash J, Elobeid A, Ran L, Benson V, et al. Exploring a United States Maize Cellulose Biofuel Scenario Using an Integrated Energy and Agricultural Markets Solution Approach. Ann Agric Crop Sci. 2017; 2(2): 1031. Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted
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