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  • 301.
    Venkataraman, Abinaya Priya
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Winter, Simon
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Rosén, Robert
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lundström, Linda
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Choice of grating orientation for evaluation of peripheral vision2016Inngår i: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 93, nr 6, s. 567-574Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: Peripheral resolution acuity depends on the orientation of the stimuli. However, it is uncertain if such a meridional effect also exists for peripheral detection tasks because they are affected by optical errors. Knowledge of the quantitative differences in acuity for different grating orientations is crucial for choosing the appropriate stimuli for evaluations of peripheral resolution and detection tasks. We assessed resolution and detection thresholds for different grating orientations in the peripheral visual field.

    Methods: Resolution and detection thresholds were evaluated for gratings of four different orientations in eight different visual field meridians in the 20-deg visual field in white light. Detection measurements in monochromatic light (543 nm; bandwidth, 10 nm) were also performed to evaluate the effects of chromatic aberration on the meridional effect. A combination of trial lenses and adaptive optics system was used to correct the monochromatic lower- and higher-order aberrations.

    Results: For both resolution and detection tasks, gratings parallel to the visual field meridian had better threshold compared with the perpendicular gratings, whereas the two oblique gratings had similar thresholds. The parallel and perpendicular grating acuity differences for resolution and detection tasks were 0.16 logMAR and 0.11 logMAD, respectively. Elimination of chromatic errors did not affect the meridional preference in detection acuity.

    Conclusions: Similar to peripheral resolution, detection also shows a meridional effect that appears to have a neural origin. The threshold difference seen for parallel and perpendicular gratings suggests the use of two oblique gratings as stimuli in alternative forced-choice procedures for peripheral vision evaluation to reduce measurement variation.

  • 302.
    Venkataraman, Abinaya Priya
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Winter, Simon
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Unsbo, Peter
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lundström, Linda
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Blur adaptation: Contrast sensitivity changes and stimulus extent2015Inngår i: Vision Research, ISSN 0042-6989, E-ISSN 1878-5646, Vol. 110, nr PA, s. 100-106Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A prolonged exposure to foveal defocus is well known to affect the visual functions in the fovea. However, the effects of peripheral blur adaptation on foveal vision, or vice versa, are still unclear. In this study, we therefore examined the changes in contrast sensitivity function from baseline, following blur adaptation to small as well as laterally extended stimuli in four subjects. The small field stimulus (7.5° visual field) was a 30. min video of forest scenery projected on a screen and the large field stimulus consisted of 7-tiles of the 7.5° stimulus stacked horizontally. Both stimuli were used for adaptation with optical blur (+2.00. D trial lens) as well as for clear control conditions. After small field blur adaptation foveal contrast sensitivity improved in the mid spatial frequency region. However, these changes neither spread to the periphery nor occurred for the large field blur adaptation. To conclude, visual performance after adaptation is dependent on the lateral extent of the adaptation stimulus.

  • 303.
    Vogt, Ulrich
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Köhler, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Dickmann, Jannis
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Rahomäki, Jussi
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Parfeniukas, Karolis
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Kubsky, S.
    Alves, F.
    Langlois, F.
    Engblom, C.
    Stankevič, T.
    Moiré method for nanometer instability investigation of scanning hard x-ray microscopes2017Inngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 25, nr 11, s. 12188-12194Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a Moiré method that can be used to investigate positional instabilities in a scanning hard x-ray microscope with nanometer precision. The development of diffractionlimited storage rings offering highly-brilliant synchrotron radiation and improvements of nanofocusing x-ray optics paves the way towards 3D nanotomography with 10 nm resolution or below. However, this trend demands improved designs of x-ray microscope instruments which should offer few-nm beam stabilities with respect to the sample. Our technique can measure the position of optics and sample stage relative to each other in the two directions perpendicular to the beam propagation in a scanning x-ray microscope using simple optical components and visible light. The usefulness of the method was proven by measuring short and long term instabilities of a zone-plate-optics-based prototype microscope. We think it can become an important tool for the characterization of scanning x-ray microscopes, especially prior to experiments with an actual x-ray beam.

  • 304.
    Vogt, Ulrich
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lindblom, M.
    Charalambous, P.
    Kaulich, B.
    Wilhein, T.
    Condenser for Koehler-like illumination in transmission x-ray microscopes at undulator sources2006Inngår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 31, nr 10, s. 1465-1467Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on a novel condenser for full-field transmission x-ray microscopes that use synchrotron radiation from an undulator source. The condenser produces a Koehler-like homogeneous intensity distribution in the sample plane and eliminates object illumination problems connected with the high degree of spatial coherence in an undulator beam. The optic consists of a large number of small linear diffraction gratings and is therefore relatively easy to manufacture. First imaging experiments with a prototype condenser were successfully performed with the Twinmic x-ray microscope at the Elettra synchrotron facility in Italy.

  • 305.
    Vogt, Ulrich
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lindblom, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Jansson, Per A. C.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Tuohimaa, Tomi T.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wieland, M.
    Wilhein, M.
    Towards Soft X-Ray Phase-Sensitive Imaging with Diffractive Optical Elements2006Inngår i: Proc. 8th International Conference X-ray Microscopy, 2006, s. 91-93Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this contribution we present the first diffractive optical elements for soft x-ray differential interference contrast microscopy.Due to an improved calculation method the nanofabrication accuracy of these optics is the same as for comparable normal zoneplate optics with the same outermost zone width. Different diffractive optical elements were fabricated with outermost zone widthof 100 nm, different spot separation directions and different phase relations between the two spots. The optics were successfullyused in experiments both at the synchrotron radiation based TWINMIC microscope and at the Stockholm compact liquid-nitrogenlaser-plasma source based microscope.

  • 306.
    Vogt, Ulrich
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lindblom, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Jansson, Per
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Tuohimaa, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wieland, M.
    University of Applied Sciences Koblenz, Rhein Ahr Campus Remagen.
    Wilhein, Thomas
    University of Applied Sciences Koblenz, Rhein Ahr Campus Remagen.
    Single-optical-element soft-x-ray interferometry with a laser-plasma x-ray source2005Inngår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 30, nr 15, s. 2167-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on a compact interferometer for the water-window soft-x-ray range that is suitable for operation with laser-plasma sources. The interferometer consists of a single diffractive optical element that focuses impinging x rays to two focal spots. The light from these two secondary sources forms the interference pattern. The interferometer was operated with a liquid-nitrogen jet laser-plasma source at lambda = 2.88 nm. Scalar wave-field propagation was used to simulate the interference pattern, showing good correspondence between theoretical and experimental results. The diffractive optical element can simultaneously be used as an imaging optic, and we demonstrate soft-x-ray microscopy with interferometric contrast enhancement of a phase object.

  • 307.
    Vogt, Ulrich
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Parfeniukas, Karolis
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Stankevic, Tomas
    Kalbfleisch, Sebastian
    Liebi, Marianne
    Matej, Zdenek
    Björling, Alexander
    Carbone, Gerardina
    Mikkelsen, Anders
    Johansson, Ulf
    First x-ray nanoimaging experiments at NanoMAX2017Inngår i: X-Ray Nanoimaging: Instruments and Methods III 2017 / [ed] Lai, B Somogyi, A, SPIE - International Society for Optical Engineering, 2017, Vol. 10389, artikkel-id 103890KKonferansepaper (Fagfellevurdert)
    Abstract [en]

    NanoMAX is a hard x-ray nanoimaging beamline at the new Swedish synchrotron radiation source MAX IV that became operational in 2016. Being a beamline dedicated to x-ray nanoimaging in both 2D and 3D, NanoMAX is the first to take full advantage of MAX IVs exceptional low emittance and resulting coherent properties. We present results from the first experiments at NanoMAX that took place in December 2016. These did not use the final experimental stations that will become available to users, but a temporary arrangement including zone plate and order-sorting aperture stages and a piezo-driven sample scanner. We used zone plates with outermost zone widths of 100 nm and 30 nm and performed experiments at 8 keV photon energy for x-ray absorption and fluorescence imaging and ptychography. Moreover, we investigated stability and coherence with a Ronchi test method. Despite the rather simple setup, we could demonstrate spatial resolution below 50 nm after only a few hours of beamtime. The results showed that the beamline is working as expected and experiments approaching the 10 nm resolution level or below should be possible in the future.

  • 308.
    Vogt, Ulrich
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Reinspach, Julia
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Uhlén, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Nilsson, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Diffractive optics for laboratory sources to free electron lasers2013Inngår i: 11th International Conference On X-Ray Microscopy (XRM2012), Institute of Physics (IOP), 2013, Vol. 463, nr 1, s. 012001-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this contribution we present our recent results in the field of diffractive optics for both soft and hard x-ray radiation, and for laboratory sources to x-ray free electron lasers (XFEL). We developed a laboratory soft x-ray microscope that uses in-house produced zone plate optics as high-resolution objectives. We continuously try to improve these optics, both in terms of efficiency and resolution. Our latest development is the manufacturing of tungsten soft x-ray zone plates with outermost zone widths of 12 nm and 90 nm high structures. For hard x-rays, we investigated the possibility to use metal zone plates on a diamond substrate for nano-focusing of the European X-ray Free Electron Laser. The simulations show that the heat conduction is efficient enough to keep a zone plate well below melting temperature. However, metal zone plates will experience large and rapid temperature fluctuations of several hundred Kelvin that might prove fatal. To test this, we manufactured tungsten on diamond prototype zone plates and exposed them to radiation from the LCLS XFEL. Results show that metal zone plates can survive the XFEL beam.

  • 309.
    von Hofsten, Olof
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Phase-Contrast and High-Resolution Optics for X-Ray Microscopy2010Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    X-ray microscopy is a well-established technique for nanoscale imaging. Zone plates are used as microscope objectives and provide high resolution, approaching 10 nm, currently limited by fabrication issues. This Thesis presents zone plate optics that achieve either high resolution or phase contrast in x-ray microscopy. The high-resolution optics use high orders of the zone plate, which alleviates the demands on fabrication, and the phase-contrast optics are single-element diffractive optical elements that produce contrast by Zernike or differential-interference contrast methods. The advantage of phase contrast in x-ray microscopy is shorter exposure times, and is crucial in the hard x-ray regime. Microscopy in the absorption‑contrast region of the water-window (2.34 - 4.37 nm) also benefits from these optics. The development of the optics for a laboratory soft x-ray microscope spans from theoretical and numerical analysis of coherence and stray light to experimental implementation and testing. The laboratory microscope uses laser-produced plasma-sources in the water-window and is unique in its design and performance. It will be shown that the laboratory microscope in its current form is a user-oriented and stable instrument, and has been used in a number of applications. The implementation of a cryogenic sample stage for tomographic imaging of biological samples in their natural environment has enabled applications in biology, and 3D x-ray microscopy of cells was performed for the first time with a laboratory instrument.

     

  • 310.
    von Hofsten, Olof
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Bertilson, Michael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lindblom, M.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Experimentell biomolekylär fysik.
    Compact Zernike phase contrast x-ray microscopy using a single-element optic2008Inngår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 33, nr 9, s. 932-934Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate Zernike phase contrast in a compact soft x-ray microscope using a single-element optic. The optic is a combined imaging zone plate and a Zernike phase plate and does not require any additional alignment or components. Contrast is increased and inversed in an image of a test object using the Zernike zone plate. This type of optic may be implemented into any existing x-ray microscope where phase contrast is of interest.

  • 311.
    von Hofsten, Olof
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Bertilson, Michael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Reinspach, Julia
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Experimentell biomolekylär fysik.
    Sub-25-nm laboratory x-ray microscopy using a compound Fresnel zone plate2009Inngår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 34, nr 17, s. 2631-2633Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Improving the resolution in x-ray microscopes is of high priority to enable future applications in nanoscience. However, high-resolution zone-plate optics often have low efficiency, which makes implementation in laboratory microscopes difficult. We present a laboratory x-ray microscope based on a compound zone plate. The compound zone plate utilizes multiple diffraction orders to achieve high resolution while maintaining reasonable efficiency. We analyze the illumination conditions necessary for this type of optics in order to suppress stray light and demonstrate microscopic imaging resolving 25 nm features.

  • 312.
    von Hofsten, Olof
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Bertilson, Michael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Experimentell biomolekylär fysik.
    Theoretical development of a high-resolution differential-interference-contrast optic for x-ray microscopy2008Inngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 16, nr 2, s. 1132-1141Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, the theoretical background and development of a differential-interference contrast (DIC) x-ray optic is presented. The single-element optic is capable of high-resolution phase contrast imaging and is compatible with compact sources. It is shown that an understanding of the coherence requirements in this type of imaging is imperative and is explained in detail. The optic is capable of a wavefront separation equal to the resolution of the optic which places only minor constraints on the object illumination.

  • 313.
    von Hofsten, Olov
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Bertilson, Michael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lindblom, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Compact phase-contrast soft X-ray microscopy2009Inngår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 186Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    For nearly all elements, the real part, delta, of the complex index of refraction n (n = 1 - delta + i beta) is larger than the imaginary part, beta, in the x-ray region. Since only beta is used in absorption contrast, phase-contrast imaging techniques which give access to delta are very important. In this paper we present two different implementations of phase contrast in our compact soft x-ray microscope, differential-interference contrast and Zemike phase contrast.

  • 314.
    von Hofsten, Olov
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Bertilson, Michael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Simulation of partially coherent image formation in x-ray microscopy - art. no. 67050I2007Inngår i: Advances in X-Ray/EUV Optics and Components II, SPIE - International Society for Optical Engineering, 2007, Vol. 6705, s. I7050-I7050Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We present the theory and implementation of a numerical model capable of simulating two-dimensional images for an x-ray microscope using partially coherent illumination considerations. Partially coherent illumination is found in all x-ray microscopes and particularly in the latest generation of our in-house compact soft x-ray microscope. This is due to an introduced mismatch in numerical aperture of the condenser and objective zone plate, and will yield diffraction-like artifacts in phase-shifting objects. The numerical model approximates the condenser zone plate as a secondary incoherent source represented by individually coherent but mutually incoherent source emitters, each giving rise to a separate image. A final image is obtained by adding up the image intensities of the individual contributions. The simulation has been a useful tool for investigating the influence of coherence on images in both the mirror and zone plate condenser arrangement of the in-house compact soft x-ray microscope. The latest development included in the program is the effect of astigmatism and partial coherence, where the calculated results show good qualitative agreement with respect to the microscope images.

  • 315.
    von Hofsten, Olov
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Takman, Per
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Voght, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Simulation of partially coherent image formation in a compact soft x-ray microscope2007Inngår i: Ultramicroscopy, ISSN 0304-3991, E-ISSN 1879-2723, Vol. 107, nr 8, s. 604-609Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we describe a numerical method of simulating two-dimensional images in a compact soft X-ray microscope using partially coherent illumination considerations. The work was motivated by recent test object images obtained by the latest generation inhouse compact soft X-ray microscope, which showed diffraction-like artifacts not observed previously. The numerical model approximates the condenser zone plate as a secondary incoherent source represented by individually coherent but mutually incoherent source points, each giving rise to a separate image. A final image is obtained by adding up all the individual source point contributions. The results are compared with the microscope images and show qualitative agreement, indicating that the observed effects are caused by partially coherent illumination.

  • 316.
    Vågberg, William
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Larsson, D. H.
    Li, M.
    Arner, A.
    Hertz, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    X-ray phase-contrast tomography for high-spatial-resolution zebrafish muscle imaging2015Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Imaging of muscular structure with cellular or subcellular detail in whole-body animal models is of key importance for understanding muscular disease and assessing interventions. Classical histological methods for high-resolution imaging methods require excision, fixation and staining. Here we show that the three-dimensional muscular structure of unstained whole zebrafish can be imaged with sub-5μm detail with X-ray phase-contrast tomography. Our method relies on a laboratory propagation-based phase-contrast system tailored for detection of low-contrast 4-6μm subcellular myofibrils. The method is demonstrated on 20 days post fertilization zebrafish larvae and comparative histology confirms that we resolve individual myofibrils in the whole-body animal. X-ray imaging of healthy zebrafish show the expected structured muscle pattern while specimen with a dystrophin deficiency (sapje) displays an unstructured pattern, typical of Duchenne muscular dystrophy. The method opens up for whole-body imaging with sub-cellular detail also of other types of soft tissue and in different animal models.

  • 317.
    Vågberg, WIlliam
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Larsson, Daniel H.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Li, Mei
    Arner, Anders
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Laboratory phase-contrast x-ray tomography for imaging of zebrafish muscle structureManuskript (preprint) (Annet vitenskapelig)
  • 318.
    Vågberg, William
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Larsson, Jakob C.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Removal of ring artifacts in microtomography by characterization of scintillator variations2017Inngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 25, nr 19, s. 23191-23198Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ring artifacts reduce image quality in tomography, and arise from faulty detector calibration. In microtomography, we have identified that ring artifacts can arise due to highspatial frequency variations in the scintillator thickness. Such variations are normally removed by a flat-field correction. However, as the spectrum changes, e. g. due to beam hardening, the detector response varies non-uniformly introducing ring artifacts that persist after flat-field correction. In this paper, we present a method to correct for ring artifacts from variations in scintillator thickness by using a simple method to characterize the local scintillator response. The method addresses the actual physical cause of the ring artifacts, in contrary to many other ring artifact removal methods which rely only on image post-processing. By applying the technique to an experimental phantom tomography, we show that ring artifacts are strongly reduced compared to only making a flat-field correction.

  • 319. Wagner, U. H.
    et al.
    Parsons, A.
    Rahomäki, Jussi
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Rau, C.
    Characterising the Large Coherence Length at Diamond's Beamline I13L2016Inngår i: Proceedings of The 12th International Conference on Synchrotron Radiation Instrumentation (SRI2015), American Institute of Physics (AIP), 2016, artikkel-id 050022Konferansepaper (Fagfellevurdert)
    Abstract [en]

    I13 is a 250 m long hard x-ray beamline (6 keV to 35 keV) at the Diamond Light Source. The beamline comprises of two independent experimental endstations: one for imaging in direct space using x-ray microscopy and one for imaging in reciprocal space using coherent diffraction based imaging techniques [1]. An outstanding feature of the coherence branch, due to its length and a new generation of ultra-stable beamline instrumentation [2], is its capability of delivering a very large coherence length well beyond 200 m, providing opportunities for unique x-ray optical experiments. In this paper we discuss the challenges of measuring a large coherence length and present quantitative measurement based on analyzing diffraction patterns from a boron fiber [3]. We also discuss the limitations of this classical method in respect to detector performance, very short and long coherence lengths. Furthermore we demonstrate how a Ronchi grating setup [4] can be used to quickly establish if the beam is coherent over a large area.

  • 320. Wahlberg, M.
    et al.
    Pettersson, A. Lindskoog
    Rosén, Robert
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Nilsson, M.
    Unsbo, Peter
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Brautaset, R.
    Clinical importance of spherical and chromatic aberration on the accommodative response in contact lens wear2011Inngår i: Journal of Modern Optics, ISSN 0950-0340, E-ISSN 1362-3044, Vol. 58, nr 19-20, s. 1696-1702Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this study was to evaluate the accommodation response under both mono-and polychromatic light while varying the amount of spherical aberration. It is thought that chromatic and spherical aberrations are directional cues for the accommodative system and could affect response time, velocity or lag. Spherical aberration is often eliminated in modern contact lenses in order to enhance image quality in the unaccommodated eye. This study was divided into two parts. The first part was done to evaluate the amount of spherical and other Zernike aberrations in the unaccommodated eye when uncorrected and with two types of correction (trial lens and spherical-aberration controlled contact lens) and the second part evaluated the dynamic accommodation responses obtained when wearing each of the corrections under polychromatic and monochromatic conditions. Measurements of accommodation showed no significant differences in time, velocity and lag of accommodation after decreasing the spherical aberration with a contact lens, neither in monochromatic nor polychromatic light. It is unlikely that small to normal changes of spherical aberration in white light or monochromatic mid-spectral light affect directional cues for the accommodative system, not in white light or mid-spectral monochromatic light, since the accommodative response did not show any change.

  • 321.
    Wang, Damao
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Li, Jing
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Salazar-Alvarez, Germán
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. Stockholm University.
    McKee, Lauren S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Srivastava, Vaibhav
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Sellberg, Jonas A.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Bulone, Vincent
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Hsieh, Yves S. Y.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Production of functionalised chitins assisted by fungal lytic polysaccharide monooxygenase2018Inngår i: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 20, nr 9, s. 2091-2100Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The gene CCT67099 from Fusarium fujikuroi was shown to encode a novel enzyme from the Lytic Polysaccharide Monooxygenase (LPMO) Family AA11. The gene was expressed and a truncated version of the enzyme, designated as FfAA11, was purified from the periplasmic space of Escherichia coli cells at high yield. FfAA11 exhibited oxidative activity against α- and β-chitins, as well as lobster shells. Under optimised conditions, FfAA11 introduced 35 nmol of carboxylate (COO) moieties per milligram of α-chitin. These carboxylate groups were introduced onto the chitin surface under mild enzymatic oxidation conditions in an aqueous solution without changes to the crystallinity of the chitin fibres. FfAA11 was also combined with a simple and environmentally friendly chemical method that transforms recalcitrant chitins into desirable functionalised (nano)materials. The use of ethyl(hydroxyimino)cyanoacetate (Oxyma)-assisted click chemistry allowed the rapid modification of the surface of FfAA11-oxidized chitins, with a fluorescent probe, a peptide, and gold nanoparticles. The chemical steps performed, including the FfAA11 oxidase treatment and surface chemical modification, were achieved without the production of any toxic by-products or waste organic solvents. This approach represents a novel method for the greener production of chitin-based biomaterials.

  • 322. Welch, C. C.
    et al.
    Olynick, D. L.
    Liu, Z.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Peroz, C.
    Robinson, A. P. G.
    Henry, M. D.
    Scherer, A.
    Mollenhauer, T.
    Genova, V.
    Ng, D. K. T.
    Formation of nanoscale structures by inductively coupled plasma etching2012Inngår i: International Conference Micro- and Nano-Electronics 2012, SPIE - International Society for Optical Engineering, 2012, s. 870002-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper will review the top down technique of ICP etching for the formation of nanometer scale structures. The increased difficulties of nanoscale etching will be described. However it will be shown and discussed that inductively coupled plasma (ICP) technology is well able to cope with the higher end of the nanoscale: features from 100nm down to about 40nm are relatively easy with current ICP technology. It is the ability of ICP to operate at low pressure yet with high plasma density and low (controllable) DC bias that helps greatly compared to simple reactive ion etching (RIE) and, though continual feature size reduction is increasingly challenging, improvements to ICP technology as well as improvements in masking are enabling sub-10nm features to be reached. Nanoscale ICP etching results will be illustrated in a range of materials and technologies. Techniques to facilitate etching (such as the use of cryogenic temperatures) and techniques to improve the mask performance will be described and illustrated.

  • 323.
    Wiedorn, Max O.
    et al.
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany.;Univ Hamburg, Dept Phys, Luruper Chaussee 149, D-22761 Hamburg, Germany.;Univ Hamburg, Hamburg Ctr Ultrafast Imaging, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Oberthuer, Dominik
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Bean, Richard
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Schubert, Robin
    Univ Hamburg, Hamburg Ctr Ultrafast Imaging, Luruper Chaussee 149, D-22761 Hamburg, Germany.;Univ Hamburg, Inst Biochem & Mol Biol, Lab Struct Biol Infect & Inflammat, Notkestr 85, D-22607 Hamburg, Germany.;Integrated Biol Infrastruct Life Sci Facil Europe, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Werner, Nadine
    Univ Hamburg, Inst Biochem & Mol Biol, Lab Struct Biol Infect & Inflammat, Notkestr 85, D-22607 Hamburg, Germany..
    Abbey, Brian
    La Trobe Univ, Ctr Excellence Adv Mol Imaging, La Trobe Inst Mol Sci, Dept Chem & Phys,ARC, Bundoora, Vic 3086, Australia..
    Aepfelbacher, Martin
    Univ Med Ctr Hamburg Eppendorf UKE, Inst Med Microbiol Virol & Hyg, D-20246 Hamburg, Germany..
    Adriano, Luigi
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Allahgholi, Aschkan
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Al-Qudami, Nasser
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Andreasson, Jakob
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, S-75124 Uppsala, Sweden.;Czech Acad Sci, ELI Beamlines, Inst Phys, Na Slovance 2, Prague 18221, Czech Republic.;Chalmers Univ Technol, Dept Phys, Condensed Matter Phys, S-41296 Gothenburg, Sweden..
    Aplin, Steve
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Awel, Salah
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany.;Univ Hamburg, Hamburg Ctr Ultrafast Imaging, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Ayyer, Kartik
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Bajt, Sasa
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Barak, Imrich
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany.;Univ Hamburg, Hamburg Ctr Ultrafast Imaging, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Bari, Sadia
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Bielecki, Johan
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Botha, Sabine
    Univ Hamburg, Hamburg Ctr Ultrafast Imaging, Luruper Chaussee 149, D-22761 Hamburg, Germany.;Univ Hamburg, Inst Biochem & Mol Biol, Lab Struct Biol Infect & Inflammat, Notkestr 85, D-22607 Hamburg, Germany..
    Boukhelef, Djelloul
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Brehm, Wolfgang
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Brockhauser, Sandor
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany.;Hungarian Acad Sci, BRC, Temesvari Krt 62, H-6726 Szeged, Hungary..
    Cheviakov, Igor
    Univ Med Ctr Hamburg Eppendorf UKE, Inst Med Microbiol Virol & Hyg, D-20246 Hamburg, Germany..
    Coleman, Matthew A.
    Lawrence Livermore Natl Lab, 7000 East Ave, Livermore, CA 94550 USA..
    Cruz-Mazo, Francisco
    Univ Seville, Dept Ingn Aeroesp & Mecan Fluidos ETSI, Seville 41092, Spain..
    Danilevski, Cyril
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Darmanin, Connie
    La Trobe Univ, Ctr Excellence Adv Mol Imaging, La Trobe Inst Mol Sci, Dept Chem & Phys,ARC, Bundoora, Vic 3086, Australia..
    Doak, R. Bruce
    Max Planck Inst Med Res, Jahnstr 29, D-69120 Heidelberg, Germany..
    Domaracky, Martin
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Doerner, Katerina
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Du, Yang
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Fangohr, Hans
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany.;Univ Southampton, Engn & Environm, Southampton SO17 1BJ, Hants, England..
    Fleckenstein, Holger
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Frank, Matthias
    Lawrence Livermore Natl Lab, 7000 East Ave, Livermore, CA 94550 USA..
    Fromme, Petra
    Arizona State Univ, Sch Mol Sci & Biodesign, Ctr Appl Struct Discovery, Tempe, AZ 85287 USA..
    Ganan-Calvo, Alfonso M.
    Univ Seville, Dept Ingn Aeroesp & Mecan Fluidos ETSI, Seville 41092, Spain..
    Gevorkov, Yaroslav
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany.;Hamburg Univ Technol, Vis Syst E2, Harburger Schlostr 20, D-21079 Hamburg, Germany..
    Giewekemeyer, Klaus
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Ginn, Helen Mary
    Div Struct Biol, Oxford OX3 7BN, England.;Diamond Light Source, Res Complex Harwell, Diamond House,Harwell Sci & Innovat Campus, Didcot OX11 0DE, Oxon, England.;Univ Oxford, Diamond House,Harwell Sci & Innovat Campus, Didcot OX11 0DE, Oxon, England..
    Graafsma, Heinz
    DESY, Notkestr 85, D-22607 Hamburg, Germany.;Mid Sweden Univ, Holmgatan 10, S-85170 Sundsvall, Sweden..
    Graceffa, Rita
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Greiffenberg, Dominic
    Paul Scherrer Inst, Forsch Str 111, CH-5232 Villigen, Switzerland..
    Gumprecht, Lars
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Goettlicher, Peter
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Hajdu, Janos
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, S-75124 Uppsala, Sweden.;Czech Acad Sci, ELI Beamlines, Inst Phys, Na Slovance 2, Prague 18221, Czech Republic..
    Hauf, Steffen
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Heymann, Michael
    Max Planck Inst Biochem, Dept Cellular & Mol Biophys, D-82152 Martinsried, Germany..
    Holmes, Susannah
    La Trobe Univ, Ctr Excellence Adv Mol Imaging, La Trobe Inst Mol Sci, Dept Chem & Phys,ARC, Bundoora, Vic 3086, Australia..
    Horke, Daniel A.
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany.;Univ Hamburg, Hamburg Ctr Ultrafast Imaging, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Hunter, Mark S.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Menlo Pk, CA 94025 USA..
    Imlau, Siegfried
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Kaukher, Alexander
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Kim, Yoonhee
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Klyuev, Alexander
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Knoska, Juraj
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany.;Univ Hamburg, Dept Phys, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Kobe, Bostjan
    Univ Queensland, Inst Mol Biosci, Sch Chem & Mol Biosci, Brisbane, Qld 4072, Australia.;Univ Queensland, Australian Infect Dis Res Ctr, Brisbane, Qld 4072, Australia..
    Kuhn, Manuela
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Kupitz, Christopher
    Univ Wisconsin, Phys Dept, 3135 N Maryland Ave, Milwaukee, WI 53211 USA..
    Kueper, Jochen
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany.;Univ Hamburg, Dept Phys, Luruper Chaussee 149, D-22761 Hamburg, Germany.;Univ Hamburg, Hamburg Ctr Ultrafast Imaging, Luruper Chaussee 149, D-22761 Hamburg, Germany.;Univ Hamburg, Dept Chem, Martin Luther King Pl 6, D-20146 Hamburg, Germany..
    Lahey-Rudolph, Janine Mia
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany.;Univ Lubeck, Inst Biochem, Ctr Struct & Cell Biol Med, Ratzeburger Allee 160, D-23562 Lubeck, Germany..
    Laurus, Torsten
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Le Cong, Karoline
    Univ Hamburg, Inst Biochem & Mol Biol, Lab Struct Biol Infect & Inflammat, Notkestr 85, D-22607 Hamburg, Germany..
    Letrun, Romain
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Xavier, P. Lourdu
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany.;Max Planck Inst Struct & Dynam Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Maia, Luis
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Maia, Filipe R. N. C.
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, S-75124 Uppsala, Sweden.;Lawrence Berkeley Natl Lab, NERSC, Berkeley, CA 94720 USA..
    Mariani, Valerio
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Messerschmidt, Marc
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Metz, Markus
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Mezza, Davide
    Paul Scherrer Inst, Forsch Str 111, CH-5232 Villigen, Switzerland..
    Michelat, Thomas
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Mills, Grant
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Monteiro, Diana C. F.
    Univ Hamburg, Hamburg Ctr Ultrafast Imaging, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Morgan, Andrew
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Muhlig, Kerstin
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, S-75124 Uppsala, Sweden..
    Munke, Anna
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, S-75124 Uppsala, Sweden..
    Muennich, Astrid
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Nette, Julia
    Univ Hamburg, Hamburg Ctr Ultrafast Imaging, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Nugent, Keith A.
    La Trobe Univ, Ctr Excellence Adv Mol Imaging, La Trobe Inst Mol Sci, Dept Chem & Phys,ARC, Bundoora, Vic 3086, Australia..
    Nuguid, Theresa
    Univ Hamburg, Inst Biochem & Mol Biol, Lab Struct Biol Infect & Inflammat, Notkestr 85, D-22607 Hamburg, Germany..
    Orville, Allen M.
    Diamond Light Source, Res Complex Harwell, Diamond House,Harwell Sci & Innovat Campus, Didcot OX11 0DE, Oxon, England.;Univ Oxford, Diamond House,Harwell Sci & Innovat Campus, Didcot OX11 0DE, Oxon, England..
    Pandey, Suraj
    Univ Wisconsin, Phys Dept, 3135 N Maryland Ave, Milwaukee, WI 53211 USA..
    Pena, Gisel
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Villanueva-Perez, Pablo
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Poehlsen, Jennifer
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Previtali, Gianpietro
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Redecke, Lars
    Univ Med Ctr Hamburg Eppendorf UKE, Inst Med Microbiol Virol & Hyg, D-20246 Hamburg, Germany.;Univ Lubeck, Inst Biochem, Ctr Struct & Cell Biol Med, Ratzeburger Allee 160, D-23562 Lubeck, Germany..
    Riekehr, Winnie Maria
    Univ Lubeck, Inst Biochem, Ctr Struct & Cell Biol Med, Ratzeburger Allee 160, D-23562 Lubeck, Germany..
    Rohde, Holger
    Univ Med Ctr Hamburg Eppendorf UKE, Inst Med Microbiol Virol & Hyg, D-20246 Hamburg, Germany..
    Round, Adam
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Safenreiter, Tatiana
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Sarrou, Iosifina
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Sato, Tokushi
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany.;European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Schmidt, Marius
    Univ Wisconsin, Phys Dept, 3135 N Maryland Ave, Milwaukee, WI 53211 USA..
    Schmitt, Bernd
    Paul Scherrer Inst, Forsch Str 111, CH-5232 Villigen, Switzerland..
    Schoenherr, Robert
    Univ Lubeck, Inst Biochem, Ctr Struct & Cell Biol Med, Ratzeburger Allee 160, D-23562 Lubeck, Germany..
    Schulz, Joachim
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Sellberg, Jonas A.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Seibert, M. Marvin
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, S-75124 Uppsala, Sweden..
    Seuring, Carolin
    SAS, Inst Mol Biol, Dubravska Cesta 21, Bratislava 84551, Slovakia..
    Shelby, Megan L.
    Lawrence Livermore Natl Lab, 7000 East Ave, Livermore, CA 94550 USA..
    Shoeman, Robert L.
    Max Planck Inst Med Res, Jahnstr 29, D-69120 Heidelberg, Germany..
    Sikorski, Marcin
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Silenzi, Alessandro
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Stan, Claudiu A.
    Rutgers Univ Newark, Phys Dept, Newark, NJ 07102 USA..
    Shi, Xintian
    Paul Scherrer Inst, Forsch Str 111, CH-5232 Villigen, Switzerland..
    Stern, Stephan
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany.;European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Sztuk-Dambietz, Jola
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Szuba, Janusz
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Tolstikova, Aleksandra
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Trebbin, Martin
    Univ Hamburg, Hamburg Ctr Ultrafast Imaging, Luruper Chaussee 149, D-22761 Hamburg, Germany.;Univ Buffalo, Dept Chem, 359 Nat Sci Complex, Buffalo, NY 14260 USA.;Univ Hamburg, Inst Nanostruct & Solid State Phys, Dept Phys, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Trunk, Ulrich
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Vagovic, Patrik
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany.;European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Ve, Thomas
    Griffith Univ, Inst Glyc, Southport, Qld 4222, Australia..
    Weinhausen, Britta
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    White, Thomas A.
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Wrona, Krzysztof
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Xu, Chen
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Yefanov, Oleksandr
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Zatsepin, Nadia
    Arizona State Univ, Dept Phys, Tempe, AZ 85287 USA..
    Zhang, Jiaguo
    Paul Scherrer Inst, Forsch Str 111, CH-5232 Villigen, Switzerland..
    Perbandt, Markus
    Univ Hamburg, Hamburg Ctr Ultrafast Imaging, Luruper Chaussee 149, D-22761 Hamburg, Germany.;Univ Hamburg, Inst Biochem & Mol Biol, Lab Struct Biol Infect & Inflammat, Notkestr 85, D-22607 Hamburg, Germany.;Univ Med Ctr Hamburg Eppendorf UKE, Inst Med Microbiol Virol & Hyg, D-20246 Hamburg, Germany..
    Mancuso, Adrian P.
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Betzel, Christian
    Univ Hamburg, Hamburg Ctr Ultrafast Imaging, Luruper Chaussee 149, D-22761 Hamburg, Germany.;Univ Hamburg, Inst Biochem & Mol Biol, Lab Struct Biol Infect & Inflammat, Notkestr 85, D-22607 Hamburg, Germany.;Integrated Biol Infrastruct Life Sci Facil Europe, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Chapman, Henry
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany.;Univ Hamburg, Dept Phys, Luruper Chaussee 149, D-22761 Hamburg, Germany.;Univ Hamburg, Hamburg Ctr Ultrafast Imaging, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Barty, Anton
    DESY, Ctr Free Electron Laser Sci, Notkestr 85, D-22607 Hamburg, Germany..
    Megahertz serial crystallography2018Inngår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 9, artikkel-id 4025Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 324.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Acoustofluidics 12: Biocompatibility and cell viability in microfluidic acoustic resonators2012Inngår i: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 12, nr 11, s. 2018-2028Artikkel i tidsskrift (Annet vitenskapelig)
  • 325.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Affinity-Bead-Mediated Acoustophoresis: A Novel Tool in Cytometry2014Inngår i: Cytometry Part A, ISSN 1552-4922, E-ISSN 1552-4930, Vol. 85A, nr 11, s. 915-917Artikkel i tidsskrift (Fagfellevurdert)
  • 326.
    Wiklund, Martin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Brismar, Hjalmar
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Önfelt, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Acoustofluidics 18: Microscopy for acoustofluidic micro-devices2012Inngår i: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 12, nr 18, s. 3221-3234Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    In this tutorial review in the thematic series "Acoustofluidics", we discuss the implementation and practice of optical microscopy in acoustofluidic micro-devices. Examples are given from imaging of acoustophoretic manipulation of particles and cells in microfluidic channels, but most of the discussion is applicable to imaging in any lab-on-a-chip device. The discussion includes basic principles of optical microscopy, different microscopy modes and applications, and design criteria for micro-devices compatible with basic, as well as advanced, optical microscopy.

  • 327.
    Wiklund, Martin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Christakou, Athanasia E.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Iranmanesh, Ida
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ohlin, Mathias
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Russom, Aman
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    Önfelt, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    On-chip acoustic sample preparation for cell studies and diagnostics2013Inngår i: Proceedings of Meetings on Acoustics: Volume 19, 2013, Acoustical Society of America (ASA), 2013, s. 1-3Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We describe a novel platform for acoustic sample preparation in microchannels and microplates. The utilized method is based on generating a multitude of acoustic resonances at a set of different frequencies in microstructures, in order to accurately control the migration and positioning of particles and cells suspended in fluid channels and chambers. The actuation frequencies range from 30 kHz to 7 MHz, which are applied simultaneously and/or in sweeps. We present two devices: A closed microfluidic chip designed for pre-alignment, size-based separation, isolation, up-concentration and lysis of cells, and an open multi-well microplate designed for parallel aggregation and positioning of cells. Both devices in the platform are compatible with high-resolution live-cell microscopy, which is used for fluorescence-based optical characterization. Two bioapplications are demonstrated for each of the devices: The first device is used for size-selective cell isolation and lysis for DNA-based diagnostics, and the second device is used for quantifying the heterogeneity in cytotoxic response of natural killer cells interacting with cancer cells.

  • 328.
    Wiklund, Martin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Christakou, Athanasia E.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ohlin, Mathias
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Iranmanesh, Ida
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Frisk, Thomas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Vanherberghen, Bruno
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Önfelt, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Ultrasound-Induced Cell-Cell Interaction Studies in a Multi-Well Microplate2014Inngår i: Micromachines, ISSN 2072-666X, E-ISSN 2072-666X, Vol. 5, nr 1, s. 27-49Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    This review describes the use of ultrasound for inducing and retaining cell-cell contact in multi-well microplates combined with live-cell fluorescence microscopy. This platform has been used for studying the interaction between natural killer (NK) cells and cancer cells at the level of individual cells. The review includes basic principles of ultrasonic particle manipulation, design criteria when building a multi-well microplate device for this purpose, biocompatibility aspects, and finally, two examples of biological applications: Dynamic imaging of the inhibitory immune synapse, and studies of the heterogeneity in killing dynamics of NK cells interacting with cancer cells.

  • 329.
    Wiklund, Martin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Green, Roy
    Univ Southampton, Hants, England .
    Ohlin, Mathias
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Acoustofluidics 14: Applications of acoustic streaming in microfluidic devices2012Inngår i: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 12, nr 14, s. 2438-2451Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    In part 14 of the tutorial series "Acoustofluidics - exploiting ultrasonic standing wave forces and acoustic streaming in microfluidic systems for cell and particle manipulation", we provide a qualitative description of acoustic streaming and review its applications in lab-on-a-chip devices. The paper covers boundary layer driven streaming, including Schlichting and Rayleigh streaming, Eckart streaming in the bulk fluid, cavitation microstreaming and surface-acoustic-wave-driven streaming.

  • 330.
    Wiklund, Martin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Gunther, C.
    Lemor, R.
    Jager, M.
    Fuhr, G.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ultrasonic standing wave manipulation technology integrated into a dielectrophoretic chip2006Inngår i: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 6, nr 12, s. 1537-1544Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Several cell-based biological applications in microfluidic systems require simultaneous high-throughput and individual handling of cells or other bioparticles. Available chip-based tools for contactless manipulation are designed for either high-precision handling of individual particles, or high-throughput handling of ensembles of particles. In order to simultaneously perform both, we have combined two manipulation technologies based on ultrasonic standing waves (USWs) and dielectrophoresis (DEP) in a microfluidic chip. The principle is based on the competition between long-range ultrasonic forces, short-range dielcctrophoretic forces and viscous drag forces from the fluid flow. The ultrasound is coupled into the microchannel resonator by an external transducer with a refractive element placed on top of the chip, thereby allowing transmission light microscopy to continuously monitor the biological process. The DEP manipulation is generated by an electric field between co-planar microelectrodes placed on the bottom surface of the fluid channel. We demonstrate flexible and gentle elementary manipulation functions by the use of USWs and linear or curved DEP deflector elements that can be used in high-throughput biotechnology applications of individual cells.

  • 331.
    Wiklund, Martin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ultrasonic enhancement of bead-based bioaffinity assays2006Inngår i: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 6, nr 10, s. 1279-1292Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Ultrasonic radiation forces can be used for non-intrusive manipulation and concentration of suspended micrometer-sized particles. For bioanalytical purposes, standing-wave ultrasound has long been used for rapid immuno-agglutination of functionalized latex beads. More recently, detection methods based on laser-scanning fluorometry and single-step homogeneous bead-based assays show promise for fast, easy and sensitive biochemical analysis. If such methods are combined with ultrasonic enhancement, detection limits in the femtomolar region are feasible. In this paper, we review the development of standing-wave ultrasonic manipulation for bioanalysis, with special emphasis on miniaturization and ultrasensitive bead-based immunoassays.

  • 332.
    Wiklund, Martin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hultström, Jessica
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Manneberg, Otto
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ultrasonic manipulation in a microfluidic chip for individual handling of particles and cells2006Inngår i: Micro Total Analysis Systems - Proceedings of MicroTAS 2006 Conference: 10th International Conference on Miniaturized Systems for Chemistry and Life Sciences, Japan Academic Association Inc , 2006, s. 446-448Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We have developed a microfluidic platform for individual particle handling by the use of ultrasonic standing waves. Elementary manipulation functions, useful in cell-based biotechnology applications, are demonstrated. Oblique coupling of ultrasound allows for any kind of high-NA optical microscopy, which is important for individual characterization of cells.

  • 333.
    Wiklund, Martin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Nord, O.
    Gothall, R.
    Chernyshev, A. V.
    Nygren, Per-Åke
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Fluorescence-microscopy-based image analysis for analyte-dependent particle doublet detection in a single-step immuno agglutination assay2005Inngår i: Analytical Biochemistry, ISSN 0003-2697, E-ISSN 1096-0309, Vol. 338, nr 1, s. 90-101Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel fluorescence-microscopy-based image analysis method for classification of singlet and doublet latex particles is demonstrated and applied to a particle-based immunoagglutination assay for quantification of biomolecules in microliter-volume bulk samples. The image analysis method, verified by flow cytometric agglutination analysis, is based on a pattern recognition algorithm employing Gaussian-base-function fitting which allows robust identification and counting of singlets, doublets, and higher agglomerates of fluorescent microparticles. The immunoagglutination assay is experimentally modeled by a biotin-streptavidin interaction, with the goal of both theoretically and experimentally investigating the performance of a general immunoagglutination-based assay. For this purpose a theoretical model of the initial agglutination kinetics, based on particle diffusion combined with a steric factor determined by the level of specific and nonspecific agglutination, was developed. The theoretical model combined with the experimental data can be used to optimize an agglutination-based assay with regard to sensitivity and dynamic range and to estimate the affinity, receptor surface density, molecular and binding site sizes, and level of nonspecific binding that is present in the assay. The experimental results are in good agreement with the theoretical model, indicating the usefulness of the model for immunoagglutination assay optimization.

  • 334.
    Wiklund, Martin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Radel, Stefan
    Hawkes, Jeremy J.
    Acoustofluidics 21: ultrasound-enhanced immunoassays and particle sensors2013Inngår i: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 13, nr 1, s. 25-39Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    In part 21 of the tutorial series "Acoustofluidics - exploiting ultrasonic standing wave forces and acoustic streaming in microfluidic systems for cell and particle manipulation'', we review applications of ultrasonic standing waves used for enhancing immunoassays and particle sensors. The paper covers ultrasonic enhancement of bead-based immuno-agglutination assays, bead-based immuno-fluorescence assays, vibrational spectroscopy sensors and cell deposition on a sensor surface.

  • 335.
    Wiklund, Martin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Önfelt, B.
    Ultrasonic manipulation of single cells2012Inngår i: Single-Cell Analysis, Springer Science+Business Media B.V., 2012, Vol. 853, s. 177-196Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Ultrasonic manipulation has emerged as a simple and powerful tool for trapping, aggregation, and separation of cells. During the last decade, an increasing amount of applications in the microscale format has been demonstrated, of which the most important is acoustophoresis (continuous acoustic cell or particle separation). Traditionally, the technology has proven to be suitable for treatment of high-density cell and particle suspensions, where large cell and particle numbers are handled simultaneously. In this chapter, we describe how ultrasound can be combined with microfluidics and microplates for particle and cell manipulation approaching the single-cell level. We demonstrate different cell handling methods with the purpose to select, trap, aggregate, and position individual cells in microdevices based on multifrequency ultrasonic actuation, and we discuss applications of the technology involving immune cell interaction studies.

  • 336.
    Winter, Simon
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Transverse Chromatic Aberration and Vision: Quantification and Impact across the Visual Field2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The eye is our window to the world. Human vision has therefore been extensively studied over the years. However, in-depth studies are often either limited to our central visual field, or, when extended to the periphery, only correct optical errors related to a narrow spectrum of light. This thesis extends the current knowledge by considering the full visible spectrum over a wide visual field. A broad spectrum means that the wavelength dependence of light propagation inside the eye has to be considered; the optics of the eye will therefore not form a retinal image in the same location for all wavelengths, a phenomenon called chromatic aberration.

    We present here a new methodology to objectively measure the magnitude of transverse chromatic aberration (TCA) across the visual field of the human eye, and show that the ocular TCA increases linearly with off-axis angle (about 0.21 arcmin per degree for the spectral range from 543 nm to 842 nm). Moreover, we have implemented adaptive psychophysical methods to quantify the impact of TCA on central and peripheral vision. We have found that inducing additional TCA degrades peripheral grating detection acuity more than foveal resolution acuity (more than 0.05 logMAR per arcmin of induced TCA peripherally compared to 0.03 logMAR/arcmin foveally). As stimuli to evaluate peripheral vision, we recommend gratings that are obliquely-oriented relative to the visual field meridian.

    The results of this thesis have clinical relevance for improving peripheral vision and are equally important for retinal imaging techniques. To limit the negative impacts of TCA on vision, inducing additional TCA should be avoided when the peripheral refractive errors are to be corrected, such as for people suffering from macular degeneration and central visual field loss. In retinal imaging applications, TCA leads to lateral offsets when imaging is performed in more than one wavelength. Consequently, the measurement of TCA together with careful pupil alignment and subsequent compensation can improve the functionality of these instruments.

  • 337.
    Winter, Simon
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Fathi, Mohammad Taghi
    Venkataraman, Abinaya Priya
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Rosén, Robert
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Seidemann, Anne
    Esser, Gregor
    Lundström, Linda
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Unsbo, Peter
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Effect of induced transverse chromatic aberration on peripheral vision2015Inngår i: Optical Society of America. Journal A: Optics, Image Science, and Vision, ISSN 1084-7529, E-ISSN 1520-8532, Vol. 32, nr 10, s. 1764-1771Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Transverse chromatic aberration (TCA) is one of the largest optical errors affecting the peripheral image quality in the human eye. However, the effect of chromatic aberrations on our peripheral vision is largely unknown. This study investigates the effect of prism-induced horizontal TCA on vision, in the central as well as in the 20 degrees nasal visual field, for four subjects. Additionally, the magnitude of induced TCA (in minutes of arc) was measured subjectively in the fovea with a Vernier alignment method. During all measurements, the monochromatic optical errors of the eye were compensated for by adaptive optics. The average reduction in foveal grating resolution was about 0.032 +/- 0.005 logMAR/arcmin of TCA (mean +/- std). For peripheral grating detection, the reduction was 0.057 +/- 0.012 logMAR/arcmin. This means that the prismatic effect of highly dispersive spectacles may reduce the ability to detect objects in the peripheral visual field.

  • 338.
    Winter, Simon
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. Royal Inst Technol, Biomed & Xray Phys, Stockholm, Sweden..
    Lundström, Linda
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Fathi, Mohammad Taghi
    Rodenstock GmbH, Corp Res & Dev, Munich, Germany..
    Venkataraman, Abinaya Priya
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Seidemann, Anne
    Rodenstock GmbH, Corp Res & Dev, Munich, Germany..
    Unsbo, Peter
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Horizontally induced transverse chromatic aberration reduces peripheral acuity2014Inngår i: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 55, nr 13Artikkel i tidsskrift (Annet vitenskapelig)
  • 339.
    Winter, Simon
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Sabesan, Ramkumar
    Tiruveedhula, Pavan N.
    Privitera, Claudio
    Lundström, Linda
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Roorda, Austin
    Objective measurements of transverse chromatic aberration across the visual field of the human eye2015Inngår i: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 56, nr 7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: The purpose of this study was to use a new image-based technique to make the first-ever objective measures of TCA at different eccentricities within the human visual field.

    Methods: TCA was measured at visual field angles of 0.5, 2.5, 5, 7.5, 10, 12.5, and 15 degrees from foveal fixation in the right eye of 4 subjects. Interleaved retinal images were taken at wavelengths 543 nm and 842 nm in an adaptive optics scanning laser ophthalmoscope (AOSLO) and were cross-correlated according to methods described in Harmening et al., Biomed Opt Express, 2012. Pupil alignment was controlled with a pupil-camera. To obtain true measures of human eye TCA, the contributions of the AOSLO system TCA were measured using an on-axis aligned model eye and subtracted from the human eye data.

    Results: The system TCA was stable at around 3 arcmin. On all subjects, it was possible to measure TCA out to 12.5 degrees in the nasal, 10 degrees in the temporal, 12.5 degrees in the inferior, and 15 degrees in the superior visual field. The absolute amount of TCA between green and IR varied somewhat between subjects, but was approximately 4 arcmin at 10 degrees out in the nasal visual field. However, the increase in TCA was found to be linear with a slope close to 0.2 arcmin / degree of visual field angle for all subjects. Translating these results to the visual spectrum would yield a slightly higher slope and larger image shifts, which agree with the theoretical calculations by Thibos, J. Opt. Soc. Am. A, 1987.

    Conclusions: We have performed the first objective measurement of the TCA of the human eye across the central 30 degrees visual field. The 4 arcmin of TCA at 10 degrees off-axis is very similar to the resolution acuity of 0.5 to 0.7 logMAR at 10 degrees out in the nasal visual field (about 3 to 5 arcmin). Additionally, the measured cone-size at 10 degrees in the subjects of this study was about 1.4 - 1.7 arcmin, which means that the TCA blur covers around 2-3 cones. Therefore, the peripheral TCA can be visually significant.

  • 340.
    Winter, Simon
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Sabesan, Ramkumar
    Tiruveedhula, Pavan
    Privitera, Claudio
    Unsbo, Peter
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lundström, Linda
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Roorda, Austin
    Transverse chromatic aberration across the visual field of the human eye2016Inngår i: Journal of Vision, ISSN 1534-7362, E-ISSN 1534-7362, Vol. 16, nr 14, artikkel-id 9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The purpose of this study was to measure the transverse chromatic aberration (TCA) across the visual field of the human eye objectively. TCA wasmeasured at horizontal and vertical field angles out to ±15° from foveal fixation in the right eye of four subjects. Interleaved retinal images were taken at wavelengths 543 nm and 842 nm in an adaptive optics scanning laser ophthalmoscope (AOSLO). To obtain true measures of the human eye's TCA, the contributions of the AOSLO system's TCA were measured using an on-axis aligned model eye and subtracted from the ocular data. The increase in TCA was found to be linear with eccentricity, with an average slope of 0.21 arcmin/degree of visual field angle (corresponding to 0.41 arcmin/degree for 430 nm to 770 nm). The absolute magnitude of ocular TCA varied between subjects, but was similar to the resolution acuity at 10° in the nasal visual field, encompassing three to four cones. Therefore, TCA can be visually significant. Furthermore, for high-resolution imaging applications, whether visualizing or stimulating cellular features in the retina, it is important to consider the lateral displacements between wavelengths and the variation in blur over the visual field.

  • 341.
    Wolffsohn, James S.
    et al.
    Aston Univ, Ophthalm Res Grp, Birmingham, W Midlands, England..
    Kollbaum, Pete S.
    Indiana Univ, Sch Optometry, Bloomington, IN USA..
    Berntsen, David A.
    Univ Houston, Coll Optometry, Ocular Surface Inst, Houston, TX USA..
    Atchison, David A.
    Queensland Univ Technol, Sch Optometry & Vis Sci, Inst Hlth & Biomed Innovat, Brisbane, Qld, Australia..
    Benavente, Alexandra
    SUNY Coll Optometry, New York, NY 10036 USA..
    Bradley, Arthur
    Indiana Univ, Sch Optometry, Bloomington, IN USA..
    Buckhurst, Hetal
    Plymouth Univ, Sch Hlth Profess, Peninsula Allied Hlth Ctr, Plymouth, Devon, England..
    Collins, Michael
    Queensland Univ Technol, Sch Optometry & Vis Sci, Inst Hlth & Biomed Innovat, Brisbane, Qld, Australia..
    Fujikado, Takashi
    Osaka Univ, Grad Sch Med, Dept Appl Visual Sci, Osaka, Japan..
    Hiraoka, Takahiro
    Univ Tsukuba, Dept Ophthalmol, Fac Med, Ibaraki, Japan..
    Hirota, Masakazu
    Osaka Univ, Grad Sch Med, Dept Appl Visual Sci, Osaka, Japan..
    Jones, Debbie
    Univ Waterloo, Sch Optometry & Vis Sci, Waterloo, ON, Canada..
    Logan, Nicola S.
    Aston Univ, Ophthalm Res Grp, Birmingham, W Midlands, England..
    Lundström, Linda
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Torii, Hidemasa
    Keio Univ, Sch Med, Dept Ophthalmol, Tokyo, Japan..
    Read, Scott A.
    Queensland Univ Technol, Sch Optometry & Vis Sci, Inst Hlth & Biomed Innovat, Brisbane, Qld, Australia..
    Naidoo, Kovin
    Univ KwaZulu Natal, African Vis Res Inst, Durban, South Africa..
    IMI - Clinical Myopia Control Trials and Instrumentation Report2019Inngår i: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 60, nr 3, s. M132-M160Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The evidence-basis based on existing myopia control trials along with the supporting academic literature were reviewed; this informed recommendations on the outcomes suggested from clinical trials aimed at slowing myopia progression to show the effectiveness of treatments and the impact on patients. These outcomes were classified as primary (refractive error and/or axial length), secondary (patient reported outcomes and treatment compliance), and exploratory (peripheral refraction, accommodative changes, ocular alignment, pupil size, outdoor activity/lighting levels, anterior and posterior segment imaging, and tissue biomechanics). The currently available instrumentation, which the literature has shown to best achieve the primary and secondary outcomes, was reviewed and critiqued. Issues relating to study design and patient selection were also identified. These findings and consensus from the International Myopia Institute members led to final recommendations to inform future instrumentation development and to guide clinical trial protocols.

  • 342. Zanette, I.
    et al.
    Zdora, M. -C
    Zhou, Tunhe
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Burvall, Anna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Larsson, Daniel H.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Thibault, P.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Pfeiffer, F.
    X-ray microtomography using correlation of near-field speckles for material characterization2015Inngår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 112, nr 41, s. 12569-12573Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nondestructive microscale investigation of objects is an invaluable tool in life and materials sciences. Currently, such investigation is mainly performed with X-ray laboratory systems, which are based on absorption-contrast imaging and cannot access the information carried by the phase of the X-ray waves. The phase signal is, nevertheless, of great value in X-ray imaging as it is complementary to the absorption information and in general more sensitive to visualize features with small density differences. Synchrotron facilities, which deliver a beam of high brilliance and high coherence, provide the ideal condition to develop such advanced phase-sensitive methods, but their access is limited. Here we show how a small modification of a laboratory setup yields simultaneously quantitative and 3D absorption and phase images of the object. This single-shot method is based on correlation of X-ray near-field speckles and represents a significant broadening of the capabilities of laboratory- based X-ray tomography.

  • 343. Zanette, I.
    et al.
    Zhou, Tunhe
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Burvall, Anna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lundström, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Larsson, Daniel H.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Zdora, M.
    Thibault, P.
    Pfeiffer, F.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Speckle-Based X-Ray Phase-Contrast and Dark-Field Imaging with a Laboratory Source2014Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 112, nr 25, s. 253903-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on the observation and application of near-field speckles with a laboratory x-ray source. The detection of speckles is possible thanks to the enhanced brilliance properties of the used liquid-metal-jet source, and opens the way to a range of new applications in laboratory-based coherent x-ray imaging. Here, we use the speckle pattern for multimodal imaging of demonstrator objects. Moreover, we introduce algorithms for phase and dark-field imaging using speckle tracking, and we show that they yield superior results with respect to existing methods.

  • 344. Zdora, Marie-Christine
    et al.
    Thibault, Pierre
    Zhou, Tunhe
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Harwell Science and Innovation Campus, United Kingdom.
    Koch, Frieder J.
    Romell, Jenny
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Sala, Simone
    Last, Arndt
    Rau, Christoph
    Zanette, Irene
    X-ray Phase-Contrast Imaging and Metrology through Unified Modulated Pattern Analysis2017Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 118, nr 20, artikkel-id 203903Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a method for x-ray phase-contrast imaging and metrology applications based on the sample-induced modulation and subsequent computational demodulation of a random or periodic reference interference pattern. The proposed unified modulated pattern analysis (UMPA) technique is a versatile approach and allows tuning of signal sensitivity, spatial resolution, and scan time. We characterize the method and demonstrate its potential for high-sensitivity, quantitative phase imaging, and metrology to overcome the limitations of existing methods.

  • 345. Zdora, Marie-Christine
    et al.
    Zanette, Irene
    Zhou, Tunhe
    Koch, Frieder J.
    Romell, Jenny
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Sala, Simone
    Last, Arndt
    Ohishi, Yasuo
    Hirao, Naohisa
    Rau, Christoph
    Thibault, Pierre
    At-wavelength optics characterisation via X-ray speckle- and grating-based unified modulated pattern analysis2018Inngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 26, nr 4, s. 4989-5004Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The current advances in new generation X-ray sources are calling for the development and improvement of high-performance optics. Techniques for high-sensitivity phase sensing and wavefront characterisation, preferably performed at-wavelength, are increasingly required for quality control, optimisation and development of such devices. We here show that the recently proposed unified modulated pattern analysis (UMPA) can be used for these purposes. We characterised two polymer X-ray refractive lenses and quantified the effect of beam damage and shape errors on their refractive properties. Measurements were performed with two different setups for UMPA and validated with conventional X-ray grating interferometry. Due to its adaptability to different setups, the ease of implementation and cost-effectiveness, we expect UMPA to find applications for high-throughput quantitative optics characterisation and wavefront sensing.

  • 346.
    Zhou, Tunhe
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Laboratory X-Ray Phase-Contrast Imaging: Methods and Comparisons2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    X-ray phase-contrast imaging has seen rapid development in recent decades due to its superior performance in imaging low-absorption objects, compared to traditional attenuation x-ray imaging. Having higher demand on coherence, x-ray phase-contrast imaging is performed mostly at synchrotrons. With the development of different imaging techniques, and the development of laboratory sources and x-ray optics, x-ray phase-contrast imaging can now be implemented on laboratory systems, which is promising and practical for broader range of applications.

    The subject of this thesis is the implementation, development and comparison of different laboratory phase-contrast methods using a liquid-metal-jet source. The three x-ray phase-contrast imaging methods included in this thesis are the propagation-, grating-, and speckle-based techniques. The grating-based method has been implemented on a laboratory system with a liquid-metal-jet source, which yields several times higher brightness than a standard solid-anode microfocus source. This allows shorter exposure time or a higher signal-to-noise ratio. The performance of the grating-based method has been experimentally and numerically compared with the propagation-based method, and the dose required to observe an object as a function of the object’s diameter has been investigated with simulations. The result indicates a lower dose requirement for the propagation-based method in this system but a potential advantage for the grating-based method to detect relatively large samples using a monochromatic beam.

    The speckle-based method, both the speckle-tracking and speckle-scanning techniques, has been implemented on a laboratory system for the first time, showing its adaptability to radiation of low temporal coherence. Tomography has been performed and shows the potential applications of this method on quantitative analysis on both absorption and phase information of materials. As a basis for further optimization and comparisons to other methods, the noise properties of the differential phase contrast of the speckle-based method have been studied and an analytical expression for the noise variance introduced, showing a similarity to the grating-based method.

  • 347.
    Zhou, Tunhe
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lundström, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Larsson, Daniel H.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Burvall, Anna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Low-dose phase-contrast X-ray imaging: a comparison of two methods2013Inngår i: 11th International Conference On X-Ray Microscopy (XRM2012), Institute of Physics (IOP), 2013, s. 012041-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Propagation- and grating-based X-ray phase-contrast imaging methods are compared theoretically. As a prospective application of phase-contrast methods in medical or small animal imaging, carbon dioxide (CO2) angiography is the simulated task. The required dose for the observable blood vessel is compared through simulation. The result indicates that the propagation-based method requires lower dose in this application.

  • 348.
    Zhou, Tunhe
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lundström, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Thüring, T.
    Rutishauser, S.
    Larsson, Daniel H.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Stampanoni, M.
    David, C.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Burvall, Anna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Comparison of propagation-and grating-based x-ray phase-contrast imaging techniques with a liquid-metal-jet source2014Inngår i: Medical Imaging 2014: Physics of Medical Imaging, SPIE - International Society for Optical Engineering, 2014, s. 903353-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    X-ray phase-contrast imaging has been developed as an alternative to conventional absorption imaging, partly for its dose advantage over absorption imaging at high resolution. Grating-based imaging (GBI) and propagation-based imaging (PBI) are two phase-contrast techniques used with polychromatic laboratory sources. We compare the two methods by experiments and simulations with respect to required dose. A simulation method based on the projection approximation is designed and verified with experiments. A comparison based on simulations of the doses required for detection of an object with respect to its diameter is presented, showing that for monochromatic radiation, there is a dose advantage for PBI for small features but an advantage for GBI at larger features. However, GBI suffers more from the introduction of polychromatic radiation, in this case so much that PBI gives lower dose for all investigated feature sizes. Furthermore, we present and compare experimental images of biomedical samples. While those support the dose advantage of PBI, they also highlight the GBI advantage of quantitative reconstruction of multimaterial samples. For all experiments a liquid-metal-jet source was used. Liquid-metal-jet sources are a promising option for laboratory-based phase-contrast imaging due to the relatively high brightness and small spot size.

  • 349.
    Zhou, Tunhe
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lundström, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Thüring, Thomas
    Rutishauser, Simon
    Larsson, Daniel H.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Stampanoni, M.
    David, C.
    Hertz, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Burvall, Anna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Comparison of two x-ray phase-contrast imaging methods with a microfocus source2013Inngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 21, nr 25, s. 30183-30195Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a comparison for high-resolution imaging with a laboratory source between grating-based (GBI) and propagation-based (PBI) x-ray phase-contrast imaging. The comparison is done through simulations and experiments using a liquid-metal-jet x-ray microfocus source. Radiation doses required for detection in projection images are simulated as a function of the diameter of a cylindrical sample. Using monochromatic radiation, simulations show a lower dose requirement for PBI for small object features and a lower dose for GBI for larger object features. Using polychromatic radiation, such as that from a laboratory microfocus source, experiments and simulations show a lower dose requirement for PBI for a large range of feature sizes. Tested on a biological sample, GBI shows higher noise levels than PBI, but its advantage of quantitative refractive index reconstruction for multi-material samples becomes apparent.

  • 350.
    Zhou, Tunhe
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Zanette, Irene
    Zdora, Marie-Christine
    Lundström, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. Stanford Univ, Dept Biol Struct, Stanford, CA 94305 USA.
    Larsson, Daniel H.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Pfeiffer, Franz
    Burvall, Anna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Speckle-based x-ray phase-contrast imaging with a laboratory source and the scanning technique2015Inngår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 40, nr 12, s. 2822-2825Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The speckle-based scanning method for x-ray phase-contrast imaging is implemented with a liquid-metal-jet source. Using the two-dimensional scanning technique, the phase shift introduced by the object is retrieved in both transverse orientations, and the limitations on spatial resolution inherent to the speckle-tracking technique are avoided. This method opens up possibilities of new high-resolution multimodal applications for lab-based phasecontrast x-ray imaging.

45678 301 - 350 of 352
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