10 research outputs found

    Impact of Roadside Tree Lines on Indoor Concentrations of Traffic-Derived Particulate Matter

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    Exposure to airborne particulate pollution is associated with premature mortality and a range of inflammatory illnesses, linked to toxic components within the particulate matter (PM) assemblage. The effectiveness of trees in reducing urban PM<sub>10</sub> concentrations is intensely debated. Modeling studies indicate PM<sub>10</sub> reductions from as low as 1% to as high as ∼60%. Empirical data, especially at the local scale, are rare. Here, we use conventional PM<sub>10</sub> monitoring along with novel, inexpensive magnetic measurements of television screen swabs to measure changes in PM<sub>10</sub> concentrations inside a row of roadside houses, after temporarily installing a curbside line of young birch trees. Independently, the two approaches identify >50% reductions in measured PM levels inside those houses screened by the temporary tree line. Electron microscopy analyses show that leaf-captured PM is concentrated in agglomerations around leaf hairs and within the leaf microtopography. Iron-rich, ultrafine, spherical particles, probably combustion-derived, are abundant, form a particular hazard to health, and likely contribute much of the measured magnetic remanences. Leaf magnetic measurements show that PM capture occurs on both the road-proximal and -distal sides of the trees. The efficacy of roadside trees for mitigation of PM health hazard might be seriously underestimated in some current atmospheric models

    MOESM3 of Clostridium thermocellum DSM 1313 transcriptional responses to redox perturbation

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    Additional file 3. (A) Adjusted OD600 of batch cultures grown at various initial hydrogen peroxide concentrations. Cultures were grown in MTC media containing 1.1 g/L cellobiose; (B) Chemostat OD600 and measured redox potential before, during and after hydrogen peroxide addition; (C) Detailed view of boxed region indicated in panel (B)

    MOESM2 of Clostridium thermocellum DSM 1313 transcriptional responses to redox perturbation

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    Additional file 2. Calculated differential expression and adjusted p values for genes showing significant (adjusted p value < 0.05) differential expression during at least one timepoint of either methyl viologen or hydrogen peroxide exposure

    MOESM1 of Consolidated bioprocessing of Populus using Clostridium (Ruminiclostridium) thermocellum: a case study on the impact of lignin composition and structure

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    Additional file 1: Figure A.1. Carbohydrate composition of initially screened Populus biomass. Figure A.2. Fermentation products of Avicel-control CBP cultures. Figure A.3. Carbohydrate content in Populus before and after repeat autoclave sterilization. Figure A.4. Lignin content in Populus before and after repeat autoclave sterilization

    Understanding Multiscale Structural Changes During Dilute Acid Pretreatment of Switchgrass and Poplar

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    Biofuels produced from lignocellulosic biomass hold great promise as a renewable alternative energy and fuel source. To realize a cost and energy efficient approach, a fundamental understanding of the deconstruction process is critically necessary to reduce biomass recalcitrance. Herein, the structural and morphological changes over multiple scales (5–6000 Å) in herbaceous (switchgrass) and woody (hybrid poplar) biomass during dilute sulfuric acid pretreatment were explored using neutron scattering and X-ray diffraction. Switchgrass undergoes a larger increase (20–84 Å) in the average diameter of the crystalline core of the elementary cellulose fibril than hybrid poplar (19–50 Å). Switchgrass initially forms lignin aggregates with an average size of 90 Å that coalesce to 200 Å, which is double that observed for hybrid poplar, 55–130 Å. Switchgrass shows a smooth-to-rough transition in the cell wall surface morphology unlike the diffuse-to-smooth transition of hybrid poplar. Yet, switchgrass and hybrid poplar pretreated under the same experimental conditions result in pretreated switchgrass producing higher glucose yields (∼76 wt %) than pretreated hybrid poplar (∼60 wt %). This observation shows that other aspects like cellulose allomorph transitions, cellulose accessibility, cellular biopolymer spatial distribution, and enzyme–substrate interactions may be more critical in governing the enzymatic hydrolysis efficiency
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