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- Maleshlijski, S., et al.
(author)
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Imaging SPR combined with stereoscopic 3D tracking to study barnacle cyprid-surface interactions
- 2016
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In: Surface Science. - : ELSEVIER SCIENCE BV. - 0039-6028 .- 1879-2758. ; 643, s. 172-177
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Journal article (peer-reviewed)abstract
- Barnacle larvae (cyprids) explore surfaces to identify suitable settlement sites. This process is selective, and cyprids respond to numerous surface cues. To better understand the settlement process, it is desirable to simultaneously monitor both the surface exploration behavior and any close interactions with the surface. Stereoscopic 3D tracking of the cyprids provides quantitative access to surface exploration and pre-settlement rituals. Imaging surface plasmon resonance (SPR) reveals any interactions with the surfaces, such as surface inspection during bipedal walking and deposition of temporary adhesives. We report on a combination of both techniques to bring together information on swimming behavior in the vicinity of the interface and physical interactions of the cyprid with the surface. The technical requirements are described, and we applied the setup to cyprids of Balanus amphitrite. Initial data shows the applicability of the combined instrument to correlate exploration and touchdown events on surfaces with different chemical termination. (C) 2015 Published by Elsevier B.V.
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- Makarov, Sergey, et al.
(author)
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Soft X-ray diffraction patterns measured by a LiF detector with sub-micrometre resolution and an ultimate dynamic range
- 2020
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In: Journal of Synchrotron Radiation. - 0909-0495. ; 27, s. 625-632
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Journal article (peer-reviewed)abstract
- The unique diagnostic possibilities of X-ray diffraction, small X-ray scattering and phase-contrast imaging techniques applied with high-intensity coherent X-ray synchrotron and X-ray free-electron laser radiation can only be fully realized if a sufficient dynamic range and/or spatial resolution of the detector is available. In this work, it is demonstrated that the use of lithium fluoride (LiF) as a photoluminescence (PL) imaging detector allows measuring of an X-ray diffraction image with a dynamic range of ∼107 within the sub-micrometre spatial resolution. At the PETRA III facility, the diffraction pattern created behind a circular aperture with a diameter of 5μm irradiated by a beam with a photon energy of 500eV was recorded on a LiF crystal. In the diffraction pattern, the accumulated dose was varied from 1.7 × 105Jcm-3 in the central maximum to 2 × 10-2Jcm-3 in the 16th maximum of diffraction fringes. The period of the last fringe was measured with 0.8μm width. The PL response of the LiF crystal being used as a detector on the irradiation dose of 500eV photons was evaluated. For the particular model of laser-scanning confocal microscope Carl Zeiss LSM700, used for the readout of the PL signal, the calibration dependencies on the intensity of photopumping (excitation) radiation (λ = 488nm) and the gain have been obtained.
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- Vater, Svenja M., et al.
(author)
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Holographic microscopy provides new insights into the settlement of zoospores of the green alga Ulva linza on cationic oligopeptide surfaces
- 2015
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In: Biofouling (Print). - : Taylor & Francis: STM, Behavioural Science and Public Health Titles. - 0892-7014 .- 1029-2454. ; 31:2, s. 229-239
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Journal article (peer-reviewed)abstract
- Interaction of zoospores of Ulva linza with cationic, arginine-rich oligopeptide self-assembled monolayers (SAMs) is characterized by rapid settlement. Some spores settle (ie permanently attach) in a normal manner involving the secretion of a permanent adhesive, retraction of the flagella and cell wall formation, whilst others undergo pseudosettlement whereby motile spores are trapped (attached) on the SAM surface without undergoing the normal metamorphosis into a settled spore. Holographic microscopy was used to record videos of swimming zoospores in the vicinity of surfaces with different cationic oligopeptide concentrations to provide time-resolved insights into processes associated with attachment of spores. The data reveal that spore attachment rate increases with increasing cationic peptide content. Accordingly, the decrease in swimming activity in the volume of seawater above the surface accelerated with increasing surface charge. Three-dimensional trajectories of individual swimming spores showed a hit and stick motion pattern, exclusively observed for the arginine-rich peptide SAMs, whereby spores were immediately trapped upon contact with the surface.
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