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| 2. |
- Ayyer, Kartik, et al.
(författare)
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3D diffractive imaging of nanoparticle ensembles using an x-ray laser
- 2021
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Ingår i: Optica. - : Optical Society of America. - 2334-2536. ; 8:1, s. 15-23
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Tidskriftsartikel (refereegranskat)abstract
- Single particle imaging at x-ray free electron lasers (XFELs) has the potential to determine the structure and dynamics of single biomolecules at room temperature. Two major hurdles have prevented this potential from being reached, namely, the collection of sufficient high-quality diffraction patterns and robust computational purification to overcome structural heterogeneity. We report the breaking of both of these barriers using gold nanoparticle test samples, recording around 10 million diffraction patterns at the European XFEL and structurally and orientationally sorting the patterns to obtain better than 3-nm-resolution 3D reconstructions for each of four samples. With these new developments, integrating advancements in x-ray sources, fast-framing detectors, efficient sample delivery, and data analysis algorithms, we illuminate the path towards sub-nano meter biomolecular imaging. The methods developed here can also be extended to characterize ensembles that are inherently diverse to obtain their full structural landscape. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License.
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| 3. |
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| 4. |
- Brown, Nils, et al.
(författare)
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Nya metoder och miljöindikatorer för att stödja policy för hållbarkonsumtion i Sverige : Slutrapport – PRINCE fas 2
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Det första PRINCE-programmet (Policy Relevant Indicators for Consumption and Environment) pågick mellan 2014 och 2018 med målet att undersöka sätt att förbättra och utöka uppsättningen av konsumtionsbaserade indikatorer för att uppskatta miljöpåverkan kopplat till svensk konsumtion, både inom Sverige och utomlands. PRINCE-programmet avslutades 2018 med en rapport: file:///C:/Users/krn/AppData/Local/Temp/978-91-620-6842-4.pdf.Ytterligare information finns på projektets webbplats: https://www.prince-project.se/Detta ettåriga projekt (PRINCE 2) är en påbyggnad till PRINCE-programmet. Målen med PRINCE 2 har varit att kommunicera resultaten från PRINCE-programmet till Naturvårdsverket och andra nyckelaktörer, att sammanfatta användningen av PRINCE-resultat inom politik och andra områden och att vidareutveckla data och indikatorer inom fiskeområdena, tropisk avskogning, biologisk mångfald och kemikalier i syfte att förbättra befintliga och etablera nya indikatorer för att mäta miljöpåverkan från svensk konsumtion.Projektet har finansierats med medel från Naturvårdsverkets miljöforskningsanslag.Rapporten har skrivits av Nils Brown (Statistikmyndigheten SCB), Simon Croft (Stockholm Environment Institute York, University of York), Elena Dawkins (Stockholm Environment Institute), Göran Finnveden (KTH), Jonathan Green (Stockholm Environment Institute York, University of York), Martin Persson (Chalmers tekniska högskola), Susanna Roth (Statistikmyndigheten SCB), Chris West (Stockholm Environment Institute York, University of York) och Richard Wood (Norges teknisk-naturvitenskapelige universitet NTNU).Författarna svarar för rapportens innehåll. Rapporten har även publicerats på engelska (rapportnummer 7032).Naturvårdsverket mars 2022
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| 5. |
- Ekelund, Nils, et al.
(författare)
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Trends in municipal and comprehensive planning (1980-2012) from an Ecosystem Services Perspective in Southern Sweden
- 2015
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Ingår i: Book abstracts Eight International Ecosystem Services Partnership Conference 2015, Ecosystem Services for Nature, People, and Prosperity, 9-13 November 2015 Stellenbosch, South Africa. ; , s. 103-103
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In Sweden a unique project supported by the Swedish Environmental Protection Agency is developed in close collaboration with seven coastal municipalities in Skåne. These municipalities face a range of different environmental challenges, from municipalities along the eastern coast line to municipalities in the western Öresund region. Research questions and approaches are built on case studies and scenarios to assess local municipality planning processes. The objective is to study the premises of implementing the use of the Ecosystem Service (ES) approach in municipal planning and decision making. This study presents a project component that focuses on the analysis of the comprehensive plans in the city of Malmö from 1980 to 2012. Interviews with staff from municipal departments were done as a complement to the collection of data from the comprehensive plans. The results show current trends in municipal and comprehensive planning from an ES perspective, i.e., the use of ES as a tool for sustainable development. The results further show that the ES concept was explicitly first found in the comprehensive plan from 2012. Implicitly, approaches for ecosystem services management and related planning changed from “land use”, “green areas” and “green space” (1980) towards “recreation” (1990) and “biological life cycle” and “biodiversity” (2000). This change indicates that the process in local municipality planning has shifted towards a more holistic view of the importance of ecosystems for a sustainable society and healthy life, which is currently further advanced via the ES concept.
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| 6. |
- El-Khaled, Yusuf C., et al.
(författare)
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High plasticity of nitrogen fixation and denitrification of common coral reef substrates in response to nitrate availability
- 2021
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Ingår i: Marine Pollution Bulletin. - : Elsevier BV. - 0025-326X .- 1879-3363. ; 168
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen cycling in coral reefs may be affected by nutrient availability, but knowledge about concentration-dependent thresholds that modulate dinitrogen fixation and denitrification is missing. We determined the effects of different nitrate concentrations (ambient, 1, 5, 10 μM nitrate addition) on both processes under two light scenarios (i.e., light and dark) using a combined acetylene assay for two common benthic reef substrates, i.e., turf algae and coral rubble. For both substrates, dinitrogen fixation rates peaked at 5 μM nitrate addition in light, whereas denitrification was highest at 10 μM nitrate addition in the dark. At 10 μm nitrate addition in the dark, a near-complete collapse of dinitrogen fixation concurrent with a 76-fold increase in denitrification observed for coral rubble, suggesting potential threshold responses linked to the nutritional state of the community. We conclude that dynamic nitrogen cycling activity may help stabilise nitrogen availability in microbial communities associated with coral reef substrates.
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| 7. |
- El-Khaled, Yusuf C., et al.
(författare)
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In situ eutrophication stimulates dinitrogen fixation, denitrification, and productivity in Red Sea coral reefs
- 2020
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Ingår i: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 645, s. 55-66
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Tidskriftsartikel (refereegranskat)abstract
- Eutrophication (i.e. the increase of [in-]organic nutrients) may affect the functioning of coral reefs, but knowledge about the effects on nitrogen (N) cycling and its relationship to productivity within benthic reef communities is scarce. Thus, we investigated how in situ manipulated eutrophication impacted productivity along with 2 counteracting N-cycling pathways (dinitrogen [N-2]fixation, denitrification), using a combined acetylene assay. We hypothesised that N-2-fixation would decrease and denitrification increase in response to eutrophication. N fluxes and productivity (measured as dark and light oxygen fluxes assessed in incubation experiments) were determined for 3 dominant coral reef functional groups (reef sediments, turf algae, and the scleractinian coral Pocillo-pora verrucosa) after 8 wk of in situ nutrient enrichment in the central Red Sea. Using slow-release fertiliser, we increased the dissolved inorganic N concentration by up to 7-fold compared to ambient concentrations. Experimental nutrient enrichment stimulated both N-2-fixation and denitrification across all functional groups 2- to 7-fold and 2- to 4-fold, respectively. Productivity doubled in reef sediments and remained stable for turf algae and P. verrucosa. Our data therefore suggest that (1) turf algae are major N-2-fixers in coral reefs, while denitrification is widespread among all investigated groups; (2) surprisingly, and contrary to our hypothesis, both N-2-fixation and denitrification are involved in the response to moderate N eutrophication, and (3) stimulated N-2-fixation and denitrification are not directly influenced by productivity. Our findings underline the importance and ubiquity of microbial N cycling in (Red Sea) coral reefs along with its sensitivity to eutrophication.
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| 8. |
- El-Khaled, Yusuf C., et al.
(författare)
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Nitrogen fixation and denitrification activity differ between coral- and algae-dominated Red Sea reefs
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Coral reefs experience phase shifts from coral- to algae-dominated benthic communities, which could affect the interplay between processes introducing and removing bioavailable nitrogen. However, the magnitude of such processes, i.e., dinitrogen (N-2) fixation and denitrification levels, and their responses to phase shifts remain unknown in coral reefs. We assessed both processes for the dominant species of six benthic categories (hard corals, soft corals, turf algae, coral rubble, biogenic rock, and reef sands) accounting for>98% of the benthic cover of a central Red Sea coral reef. Rates were extrapolated to the relative benthic cover of the studied organisms in co-occurring coral- and algae-dominated areas of the same reef. In general, benthic categories with high N-2 fixation exhibited low denitrification activity. Extrapolated to the respective reef area, turf algae and coral rubble accounted for>90% of overall N-2 fixation, whereas corals contributed to more than half of reef denitrification. Total N-2 fixation was twice as high in algae- compared to coral-dominated areas, whereas denitrification levels were similar. We conclude that algae-dominated reefs promote new nitrogen input through enhanced N-2 fixation and comparatively low denitrification. The subsequent increased nitrogen availability could support net productivity, resulting in a positive feedback loop that increases the competitive advantage of algae over corals in reefs that experienced a phase shift.
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| 9. |
- El-Khaledl, Yusuf C., et al.
(författare)
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Simultaneous Measurements of Dinitrogen Fixation and Denitrification Associated With Coral Reef Substrates : Advantages and Limitations of a Combined Acetylene Assay
- 2020
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Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen (N) cycling in coral reefs is of key importance for these oligotrophic ecosystems, but knowledge about its pathways is limited. While dinitrogen (N-2) fixation is comparably well studied, the counteracting denitrification pathway is under-investigated, mainly because of expensive and relatively complex experimental techniques currently available. Here, we combined two established acetylene-based assays to one single setup to determine N-2-fixation and denitrification performed by microbes associated with coral reef substrates/organisms simultaneously. Accumulating target gases (ethylene for N-2-fixation, nitrous oxide for denitrification) were measured in gaseous headspace samples via gas chromatography. We measured N-2-fixation and denitrification rates of two Red Sea coral reef substrates (filamentous turf algae, coral rubble), and demonstrated, for the first time, the co-occurrence of both N-cycling processes in both substrates. N-2-fixation rates were up to eight times higher during the light compared to the dark, whereas denitrification rates during dark incubations were stimulated for turf algae and suppressed for coral rubble compared to light incubations. Our results highlight the importance of both substrates in fixing N, but their role in relieving N is potentially divergent. Absolute N-2-fixation rates of the present study correspond with rates reported previously, even though likely underestimated due to an initial lag phase. Denitrification is also presumably underestimated due to incomplete nitrous oxide inhibition and/or substrate limitation. Besides these inherent limitations, we show that a relative comparison of N-2-fixation and denitrification activity between functional groups is possible. Thus, our approach facilitates cost-efficient sample processing in studies interested in comparing relative rates of N-2-fixation and denitrification.
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| 10. |
- Knoška, Juraj, et al.
(författare)
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Ultracompact 3D microfluidics for time-resolved structural biology
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- To advance microfluidic integration, we present the use of two-photon additive manufacturing to fold 2D channel layouts into compact free-form 3D fluidic circuits with nanometer precision. We demonstrate this technique by tailoring microfluidic nozzles and mixers for time-resolved structural biology at X-ray free-electron lasers (XFELs). We achieve submicron jets with speeds exceeding 160 m s−1, which allows for the use of megahertz XFEL repetition rates. By integrating an additional orifice, we implement a low consumption flow-focusing nozzle, which is validated by solving a hemoglobin structure. Also, aberration-free in operando X-ray microtomography is introduced to study efficient equivolumetric millisecond mixing in channels with 3D features integrated into the nozzle. Such devices can be printed in minutes by locally adjusting print resolution during fabrication. This technology has the potential to permit ultracompact devices and performance improvements through 3D flow optimization in all fields of microfluidic engineering.
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