| 1. |
- Echelmeier, A., et al.
(författare)
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Segmented flow generator for serial crystallography at the European X-ray free electron laser
- 2020
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Ingår i: Nature Communications. - : Nature Research. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Serial femtosecond crystallography (SFX) with X-ray free electron lasers (XFELs) allows structure determination of membrane proteins and time-resolved crystallography. Common liquid sample delivery continuously jets the protein crystal suspension into the path of the XFEL, wasting a vast amount of sample due to the pulsed nature of all current XFEL sources. The European XFEL (EuXFEL) delivers femtosecond (fs) X-ray pulses in trains spaced 100 ms apart whereas pulses within trains are currently separated by 889 ns. Therefore, continuous sample delivery via fast jets wastes >99% of sample. Here, we introduce a microfluidic device delivering crystal laden droplets segmented with an immiscible oil reducing sample waste and demonstrate droplet injection at the EuXFEL compatible with high pressure liquid delivery of an SFX experiment. While achieving ~60% reduction in sample waste, we determine the structure of the enzyme 3-deoxy-D-manno-octulosonate-8-phosphate synthase from microcrystals delivered in droplets revealing distinct structural features not previously reported.
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| 2. |
- Wiedorn, Max O., et al.
(författare)
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Megahertz serial crystallography
- 2018
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The new European X-ray Free-Electron Laser is the first X-ray free-electron laser capable of delivering X-ray pulses with a megahertz inter-pulse spacing, more than four orders of magnitude higher than previously possible. However, to date, it has been unclear whether it would indeed be possible to measure high-quality diffraction data at megahertz pulse repetition rates. Here, we show that high-quality structures can indeed be obtained using currently available operating conditions at the European XFEL. We present two complete data sets, one from the well-known model system lysozyme and the other from a so far unknown complex of a beta-lactamase from K. pneumoniae involved in antibiotic resistance. This result opens up megahertz serial femtosecond crystallography (SFX) as a tool for reliable structure determination, substrate screening and the efficient measurement of the evolution and dynamics of molecular structures using megahertz repetition rate pulses available at this new class of X-ray laser source.
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| 3. |
- Jo, W., et al.
(författare)
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Nanosecond X-ray photon correlation spectroscopy using pulse time structure of a storage-ring source
- 2021
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Ingår i: IUCrJ. - : International Union of Crystallography. - 2052-2525. ; 8, s. 124-130
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Tidskriftsartikel (refereegranskat)abstract
- X-ray photon correlation spectroscopy (XPCS) is a routine technique to study slow dynamics in complex systems at storage-ring sources. Achieving nanosecond time resolution with the conventional XPCS technique is, however, still an experimentally challenging task requiring fast detectors and sufficient photon flux. Here, the result of a nanosecond XPCS study of fast colloidal dynamics is shown by employing an adaptive gain integrating pixel detector (AGIPD) operated at frame rates of the intrinsic pulse structure of the storage ring. Correlation functions from single-pulse speckle patterns with the shortest correlation time of 192 ns have been calculated. These studies provide an important step towards routine fast XPCS studies at storage rings. © 2021.
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| 4. |
- Hameleers, M., et al.
(författare)
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Start Spreading the News: A Comparative Experiment on the Effects of Populist Communication on Political Engagement in Sixteen European Countries
- 2018
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Ingår i: International Journal of Press-Politics. - : SAGE Publications. - 1940-1612 .- 1940-1620. ; 23:4, s. 517-538
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Tidskriftsartikel (refereegranskat)abstract
- Although populist communication has become pervasive throughout Europe, many important questions on its political consequences remain unanswered. First, previous research has neglected the differential effects of populist communication on the Left and Right. Second, internationally comparative studies are missing. Finally, previous research mostly studied attitudinal outcomes, neglecting behavioral effects. To address these key issues, this paper draws on a unique, extensive, and comparative experiment in sixteen European countries (N = 15,412) to test the effects of populist communication on political engagement. The findings show that anti-elitist populism has the strongest mobilizing effects, and anti-immigrant messages have the strongest demobilizing effects. Moreover, national conditions such as the level of unemployment and the electoral success of the populist Left and Right condition the impact of populist communication. These findings provide important insights into the persuasiveness of populist messages spread throughout the European continent.
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| 5. |
- Schindler, S., et al.
(författare)
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Floodplain management in temperate regions : Is multifunctionality enhancing biodiversity?
- 2013
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Ingår i: Environmental Evidence. - : BioMed Central Ltd.. - 2047-2382. ; 2:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Floodplains are among the most diverse, dynamic, productive and populated but also the most threatened ecosystems on Earth. Threats are mainly related to human activities that alter the landscape and disrupt fluvial processes to obtain benefits related to multiple ecosystem services (ESS). Floodplain management therefore requires close coordination among interest groups with competing claims and poses multi-dimensional challenges to policy-makers and project managers. The European Commission proposed in its recent Biodiversity Strategy to maintain and enhance European ecosystems and their services by establishing green infrastructure (GI). GI is assumed to provide multiple ecosystem functions and services including the conservation of biodiversity in the same spatial area. However, evidence for biodiversity benefits of multifunctional floodplain management is scattered and has not been synthesised. Methods/design: This protocol specifies the methods for conducting a systematic review to answer the following policy-relevant questions: a) what is the impact of floodplain management measures on biodiversity; b) how does the impact vary according to the level of multifunctionality of the measures; c) is there a difference in the biodiversity impact of floodplain management across taxa; d) what is the effect of the time since implementation on the impact of the most important measures; and e) are there any other factors that significantly modify the biodiversity impact of floodplain management measures? Within this systematic review we will assess multifunctionality in terms of ESS that are affected by an implemented intervention. Biodiversity indicators included in this systematic review will be related to the diversity, richness and abundance of species, other taxa or functional groups. We will consider if organisms are typical for and native to natural floodplain ecosystems. Specific inclusion criteria have been developed and the wide range of quality of primary literature will be evaluated with a tailor-made system for assessing susceptibility to bias and the reliability of the studies. The review is intended to bridge the science-policy interface and will provide a useful synthesis of knowledge for decision-makers at all governance levels. © 2013 Schindler et al.; licensee BioMed Central Ltd.
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| 6. |
- Schindler, S., et al.
(författare)
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Multifunctionality of floodplain landscapes : Relating management options to ecosystem services
- 2014
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Ingår i: Landscape Ecology. - : Springer Science and Business Media LLC. - 0921-2973 .- 1572-9761. ; 29:2, s. 229-244
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Tidskriftsartikel (refereegranskat)abstract
- The concept of green infrastructure has been recently taken up by the European Commission for ensuring the provision of ecosystem services (ESS). It aims at the supply of multiple ESS in a given landscape, however, the effects of a full suite of management options on multiple ESS and landscape multifunctionality have rarely been assessed. In this paper we use European floodplain landscapes as example to develop an expert based qualitative conceptual model for the assessment of impacts of landscape scale interventions on multifunctionality. European floodplain landscapes are particularly useful for such approach as they originally provided a high variety and quantity of ESS that has declined due to the strong human impact these landscapes have experienced. We provide an overview of the effects of floodplain management options on landscape multifunctionality by assessing the effects of 38 floodplain management interventions on 21 relevant ESS, as well as on overall ESS supply. We found that restoration and rehabilitation consistently increased the multifunctionality of the landscape by enhancing supply of provisioning, regulation/maintenance, and cultural services. In contrast, conventional technical regulation measures and interventions related to extraction, infrastructure and intensive land use cause decrease in multifunctionality and negative effects for the supply of all three aspects of ESS. The overview of the effects of interventions shall provide guidance for decision makers at multiple governance levels. The presented conceptual model could be effectively applied for other landscapes that have potential for a supply of a high diversity of ESS. © 2014 Springer Science+Business Media Dordrecht.
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| 7. |
- Kanaki, K., et al.
(författare)
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Statistical energy determination in neutron detector systems for neutron scattering science
- 2013
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Ingår i: IEEE Nuclear Science Symposium Conference Record. - : IEEE conference proceedings. - 9781479905348 ; , s. Art. no. 6829644-
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Konferensbidrag (refereegranskat)abstract
- The energy determination of thermal and cold neutrons could revolutionize the field of neutron scattering science and transform the instrument design for future facilities. This contribution evaluates the feasibility and potential of a statistical determination of the neutron energy in the new generation of neutron detectors. In particular, the novel technology of multi-layer 10B thin film detectors present a unique opportunity of exploiting this possibility by using the various neutron penetration depths to extract energy information. A statistical mathematical model for doing so is being developed. To this end, measurements of absorption profiles on boron carbide have been performed at the Institutt for Energiteknikk, Norway and the Helmholtz Zentrum Berlin, Germany. The results of the data analysis allow for a preliminary estimate on the feasibility and the potential of this method. © 2013 IEEE.
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| 8. |
- Schulz, B., et al.
(författare)
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Fully reflective deep ultraviolet to near infrared spectrometer and entrance optics for resonance Raman spectroscopy
- 2005
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Ingår i: Review of Scientific Instruments. - 0034-6748 .- 1089-7623. ; 76
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Tidskriftsartikel (refereegranskat)abstract
- We present the design and performance of a new triple-grating deep ultraviolet to near-infrared spectrometer. The system is fully achromatic due to the use of reflective optics. The minimization of image aberrations by using on- and off- axis parabolic mirrors as well as elliptical mirrors yields a strong stray light rejection with high resolution over a wavelength range between 165 and 1000 nm. The Raman signal is collected with a reflective entrance objective with a numerical aperture of 0.5, featuring a Cassegrain-type design. Resonance Raman studies on semiconductors and on correlated compounds, such as LaMnO3, highlight the performance of this instrument, and show diverse resonance effects between 1.96 and 5.4 eV. (c) 2005 American Institute of Physics.
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