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  • 1.
    Akan, Rabia
    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.
    Vogt, Carmen
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Toprak, M. S.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Reaction control of metal-assisted chemical etching for silicon-based zone plate nanostructures2018Inngår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 8, nr 23, s. 12628-12634Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Metal-assisted chemical etching (MACE) reaction parameters were investigated for the fabrication of specially designed silicon-based X-ray zone plate nanostructures using a gold catalyst pattern and etching solutions composed of HF and H2O2. Etching depth, zone verticality and zone roughness were studied as a function of etching solution composition, temperature and processing time. Homogeneous, vertical etching with increasing depth is observed at increasing H2O2 concentrations and elevated processing temperatures, implying a balance in the hole injection and silica dissolution kinetics at the gold-silicon interface. The etching depth decreases and zone roughness increases at the highest investigated H2O2 concentration and temperature. Possible reasons for these observations are discussed based on reaction chemistry and zone plate design. Optimum MACE conditions are found at HFH2O2 concentrations of 4.7 M:0.68 M and room temperature with an etching rate of ≈0.7 μm min-1, which is about an order of magnitude higher than previous reports. Moreover, our results show that a grid catalyst design is important for successful fabrication of vertical high aspect ratio silicon nanostructures. 

  • 2.
    Akan, Rabia
    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.
    Vogt, Carmen
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Toprak, Muhammet S.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Reaction control of metal-assisted chemical etching for silicon-based zone plate nanostructuresManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Metal-assisted chemical etching (MACE) reaction parameters were investigated for the fabrication of specially designed silicon-based x-ray zone plate nanostructures using a gold catalyst pattern and etching solutions composed of HF and H2O2. Etching depth, zone verticality and zone roughness were studied as a function of etching solution composition, temperature and processing time. Homogeneous, vertical etching with increasing depth is observed at increasing H2O2 concentrations and elevated processing temperatures, implying a balance in the hole injection and silica dissolution kinetics at the gold-silicon interface. The etching depth decreases and zone roughness increases at the highest investigated H2O2 concentration and temperature. Possible reasons for these observations are discussed based on reaction chemistry and zone plate design. Optimum MACE conditions are found at HF:H2O2 concentrations of 4.7 M:0.68 M and room temperature with an etching rate of 0.7 micrometers per minute, which is about an order of magnitude higher than previous reports. Moreover, our results show that a grid catalyst design is important for successful fabrication of vertical high aspect ratio silicon nanostructures.

  • 3. Amaya, Andrew J.
    et al.
    Pathak, Harshad
    Modak, Viraj P.
    Laksmono, Hartawan
    Loh, N. Duane
    Sellberg, Jonas A.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Sierra, Raymond G.
    McQueen, Trevor A.
    Hayes, Matt J.
    Williams, Garth J.
    Messerschmidt, Marc
    Boutet, Sebastien
    Bogan, Michael J.
    Nilsson, Anders
    Stan, Claudiu A.
    Wyslouzil, Barbara E.
    How Cubic Can Ice Be?2017Inngår i: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 8, nr 14, s. 3216-3222Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using an X-ray laser, we investigated the crystal structure of ice formed by homogeneous ice nucleation in deeply supercooled water nanodrops (r approximate to 10 nm) at similar to 225 K The nanodrops were formed by condensation of vapor in a supersonic nozzle, and the ice was probed within 100 mu s of freezing using femtosecond wide-angle X-ray scattering at the Linac Coherent Light Source free-electron X-ray laser. The X-ray diffraction spectra indicate that this ice has a metastable, predominantly cubic structure; the shape of the first ice diffraction peak suggests stacking-disordered ice with a cubicity value, chi, in the range of 0.78 +/- 0.05. The cubicity value determined here is higher than those determined in experiments with micron-sized drops but comparable to those found in molecular dynamics simulations. The high cubicity is most likely caused by the extremely low freezing temperatures and by the rapid freezing, which occurs on a similar to 1 mu s time scale in single nanodroplets.

  • 4. Attwood, D T
    et al.
    Hertz, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Midorikawa, K
    Obara, M
    Introduction to the issue on short wavelength and EUV lasers2004Inngår i: IEEE Journal of Selected Topics in Quantum Electronics, ISSN 1077-260X, E-ISSN 1558-4542, Vol. 10, nr 6, s. 1241-1243Artikkel i tidsskrift (Annet vitenskapelig)
  • 5. Ballikaya, S.
    et al.
    Oner, Y.
    Temel, T.
    Ozkal, B.
    Bailey, T. P.
    Toprak, Muhammet Sadaka
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Uher, C.
    Thermoelectric and thermal stability improvements in Nano-Cu 2 Se included Ag 2 Se2019Inngår i: Journal of Solid State Chemistry, ISSN 0022-4596, E-ISSN 1095-726X, Vol. 273, s. 122-127Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recently, silver chalcogenides have attracted great attention due to their potential application for room temperature power generation and local cooling. In this work, we report the thermoelectric properties and thermal stability of bulk Ag 2 Se with nano-Cu 2 Se inclusions ((Ag 2 Se) 1-x (Cu 2 Se) x where x = 0, 0.02 and 0.05). Ag 2 Se samples were prepared via melting, annealing and the nanocomposite was prepared by ball milling this material with required amount of nano-Cu 2 Se; finally, the samples were consolidated by spark plasma sintering. High temperature and low temperature transport properties were assessed by the measurements of the Seebeck coefficient, electrical conductivity, thermal conductivity, and Hall coefficient. The phase composition and microstructure were explored by powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis, while the thermal stability of samples was investigated via heating microscopy and heat capacity measurement. Room temperature PXRD and SEM indicated that two separate phases of Ag 2 Se and Cu 2 Se form in nano-Cu 2 Se included composites. Heating microscopy and the heat capacity measurement indicate that the thermal stability of Ag 2 Se is enhanced with increasing nano-Cu 2 Se inclusions. The sign of the Seebeck coefficient, in agreement with the Hall coefficient, shows that electrons are the dominant carriers in all samples. The electrical conductivity of the samples increases and the Seebeck coefficient decreases with increasing amount of the nano-Cu 2 Se inclusion, likely due to augmented carrier concentration. Despite the larger electrical conductivity, the thermal conductivity is suppressed with nano-Cu 2 Se inclusions. A high power factor and reduced thermal conductivity lead to a maximum ZT value of 0.45 at 875 K for (Ag 2 Se) 1-x (nano-Cu 2 Se) x sample where x is 0.05.

  • 6.
    Barnkob, Rune
    et al.
    Tech Univ Denmark, Lyngby, Denmark .
    Iranmanesh, Ida
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Bruus, Henrik
    Tech Univ Denmark, Lyngby, Denmark .
    Measuring acoustic energy density in microchannel acoustophoresis using a simple and rapid light-intensity method2012Inngår i: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 12, nr 13, s. 2337-2344Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a simple and rapid method for measuring the acoustic energy density in microchannel acoustophoresis based on light-intensity measurements of a suspension of particles. The method relies on the assumption that each particle in the suspension undergoes single-particle acoustophoresis. It is validated by the single-particle tracking method, and we show by proper re-scaling that the re-scaled light intensity plotted versus re-scaled time falls on a universal curve. The method allows for analysis of moderate-resolution images in the concentration range encountered in typical experiments, and it is an attractive alternative to particle tracking and particle image velocimetry for quantifying acoustophoretic performance in microchannels.

  • 7. Baskaran, Karthikeyan
    et al.
    Rosén, Robert
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lewis, Peter
    Unsbo, Peter
    Gustafsson, Jörgen
    Benefit of Adaptive Optics Aberration Correction at Preferred Retinal Locus2012Inngår i: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 89, nr 9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: To investigate the effect of eccentric refractive correction and full aberration correction on both high and low contrast grating resolution at the preferred retinal locus (PRL) of a single low vision subject with a longstanding central scotoma.

    Methods: The subject was a 68 year-old female with bilateral absolute central scotoma due to Stargardt’s disease. She has developed a single PRL located 25° nasally of the damaged macula in her left eye, this being the better of the two eyes. High- (100%) and low contrast (25% & 10%) grating resolution acuity was evaluated using four different correction conditions. The first two corrections were solely refractive error corrections; namely habitual spectacle correction and full sphero-cylindrical correction. The latter two corrections were two versions of adaptive optics corrections of all aberrations; namely full sphero-cylindrical refractive correction with additional aberration correction and habitual spectacle correction with aberration correction.

    Results: The mean high contrast (100%) resolution acuity with her habitual correction was 1.06 logMAR, which improved to 1.00 logMAR with full sphero-cylindrical correction. Under the same conditions, low contrast (25%) acuity improved from 1.30 logMAR to 1.14 logMAR. With adaptive optics aberration correction, the high contrast resolution acuities improved to 0.92/0.89 logMAR and the low contrast acuities, to 1.06/1.04 logMAR under both correction modalities. The low contrast (10%) resolution acuity was 1.34 logMAR with adaptive optics aberration correction; however, with purely refractive error corrections she was unable to identify the orientation of the gratings.

    Conclusion: Correction of all aberrations using adaptive optics improves both high and low contrast resolution acuity at the PRL of a single low vision subject with longstanding absolute central scotoma.

  • 8. Baskaran, Karthikeyan
    et al.
    Unsbo, Peter
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Gustafsson, Jörgen
    Influence of Age on Peripheral Ocular Aberrations2011Inngår i: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 88, nr 9, s. 1088-1098Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose. To compare peripheral lower and higher order aberrations across the horizontal (+/- 40 degrees) and inferior (-20 degrees) visual fields in healthy groups of young and old emmetropes. Methods. We have measured off-axis aberrations in the groups of 30 younger (24 +/- 3 years) and 30 older (58 +/- 5 years) emmetropes. The aberrations of OD were measured using the COAS-HD VR Shack-Hartmann aberrometer in 10 degrees steps to +/- 40 degrees horizontally and -20 degrees inferiorly in the visual field. The aberrations were quantified with Zernike polynomials for a 4 mm pupil diameter. The second-order aberration coefficients were converted to their respective refraction components (M, J(45), and J(180)). Mixed between-within subjects, analysis of variance were used to determine whether there were significant differences in the refraction and aberration components for the between-subjects variable age and the within-subjects variable eccentricity. Results. Peripheral refraction components were similar in both age groups. Among the higher order coefficients, horizontal coma (C(3)(1)) and spherical aberration (C(4)(0)) varied mostly between the groups. Coma increased linearly with eccentricity, at a more rapid rate in the older group than in the younger group. Spherical aberration was more positive in the older group compared with the younger group. Higher order root mean square increased more rapidly with eccentricity in the older group. Conclusions. Like the axial higher order aberrations, the peripheral higher order aberrations of emmetropes increase with age, particularly coma and spherical aberration.

  • 9. Battiston, S.
    et al.
    Boldrini, S.
    Saleemi, Mohsin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Famengo, A.
    Fiameni, S.
    Toprak, Muhammet
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Fabrizio, M.
    Influence of Al and Mg addition on thermoelectric properties of higher manganese silicides obtained by reactive sintering2017Inngår i: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, E-ISSN 1533-4899, Vol. 17, nr 3, s. 1668-1673Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Higher manganese silicides (HMS), represented by MnSix (x = 1.71-1.75), are promising p-type candidates for thermoelectric (TE) energy harvesting systems at intermediate temperature range. The materials are very attractive as they may replace lead based compounds due to their non-toxicity, low cost of starting materials, and high thermal and chemical stability. Dense pellets were obtained through fast reactive sintering by spark plasma sintering (SPS). The addition -or nanoinclusion, of Al and Mg permitted the figure of merit enhancement of the material obtained with this technique, reaching the highest value of 0.40 at 600°C. Morphology, composition and crystal structure of the samples were characterized by electron microscopies, energy dispersive X-ray spectroscopy, and X-ray diffraction analyses, respectively.

  • 10.
    Bertilson, Michael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Laboratory soft x-ray microscopy and tomography2011Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Soft x-ray microscopy in the water-window (λ = 2.28 nm – 4.36 nm) is based on zone-plate optics and allows high-resolution imaging of, e.g., cells and soils in their natural or near-natural environment. Three-dimensional imaging is provided via tomographic techniques, soft x-ray cryo tomography. However, soft x-ray microscopes with such capabilities have been based on large-scale synchrotron x‑ray facilities, thereby limiting their accessibility for a wider scientific community.

    This Thesis describes the development of the Stockholm laboratory soft x-ray microscope to three-dimensional cryo tomography and to new optics-based contrast mechanisms. The microscope relies on a methanol or nitrogen liquid-jet laser-plasma source, normal-incidence multilayer or zone-plate condenser optics, in-house fabricated zone-plate objectives, and allows operation at two wavelengths in the water-window, λ = 2.48 nm and λ = 2.48 nm. With the implementation of a new state-of-the-art normal-incidence multilayer condenser for operation at λ = 2.48 nm and a tiltable cryogenic sample stage the microscope now allows imaging of dry, wet or cryo-fixed samples. This arrangement was used for the first demonstration of laboratory soft x-ray cryo microscopy and tomography. The performance of the microscope has been demonstrated in a number of experiments described in this Thesis, including, tomographic imaging with a resolution of 140 nm, cryo microscopy and tomography of various cells and parasites, and for studies of aqueous soils and clays. The Thesis also describes the development and implementation of single-element differential-interference and Zernike phase-contrast zone-plate objectives. The enhanced contrast provided by these optics reduce exposure times or lowers the dose in samples and are of major importance for harder x-ray microscopy. The implementation of a high-resolution 50 nm compound zone-plate objective for sub-25-nm resolution imaging is also described. All experiments are supported by extensive numerical modelling for improved understanding of partially coherent image formation and stray light in soft x-ray microscopes. The models are useful tools for studying effects of zone plate optics or optical design of the microscope on image formation and quantitative accuracy in soft x-ray tomography.

  • 11.
    Bertilson, Michael
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    von Hofsten, Olof
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Experimentell biomolekylär fysik.
    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.
    High-resolution computed tomography with a compact soft x-ray microscope2009Inngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 17, nr 13, s. 11057-11065Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Computed tomography based on high-resolution soft x-ray microscopy utilizes the natural contrast for biological specimens provided by the water window (lambda = 2.4 - 4.4 nm) and the high resolving power of zone plate objectives. It is capable of revealing the 3D structure of biological specimens at sub-visible-microscopic resolution. To date, the technique has only been available at synchrotron-based microscopes, which limits the researchers access. In the present paper we demonstrate high-resolution soft x-ray tomography with a laboratory zone-plate-based soft x-ray microscope. The specimen, a diatom mounted on a glass capillary, was reconstructed from a tilt series of 53 images covering 180 using a filtered back projection algorithm. The resolution of the tomogram was estimated to a half period of 140 nm using a differential-phase-residual method. Cryo-fixation, increased source brightness and extended-depth-of-focus objectives are important for pushing the resolution of compact systems for biological samples.

  • 12.
    Bertilson, Michael
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    von Hofsten, Olov
    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.
    Numerical model for tomographic image formation in transmission x-ray microscopy2011Inngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 19, nr 12, s. 11578-11583Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a numerical image-formation model for investigating the influence of partial coherence, sample thickness and depth-of-focus on the accuracy of tomographic reconstructions in transmission x-ray microscopes. The model combines wave propagation through the object by finite difference techniques with Fourier methods. We include a ray-tracing model to analyse the origin of detrimental stray light in zone plate-based x-ray microscopes. These models allow optimization of x-ray microscopy systems for quantitative tomographic imaging of thick objects. Results show that both the depth-of-focus and the reconstructed local absorption coefficient are highly dependent on the degree of coherence of the optical system.

  • 13.
    Bertilson, Michael
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    von Hofsten, Olov
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lindblom, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wilhein, Thomas
    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 high-resolution differential interference contrast soft x-ray microscopy2008Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 92, nr 064104Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate high-resolution x-ray differential interference contrast (DIC) in a compact soft x-ray microscope. Phase contrast imaging is enabled by the use of a diffractive optical element objective which is matched to the coherence conditions in the microscope setup. The performance of the diffractive optical element objective is evaluated in comparison with a normal zone plate by imaging of a nickel siemens star pattern and linear grating test objects. Images obtained with the DIC optic exhibit typical DIC enhancement in addition to the normal absorption contrast. Contrast transfer functions based on modulation measurements in the obtained images show that the DIC optic gives a significant increase in contrast without reducing the spatial resolution. The phase contrast operation mode now available for our compact soft x-ray microscope will be a useful tool for future studies of samples with low absorption contrast.

  • 14.
    Bertilson, Michael
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    von Hofsten, Olov
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Thieme, J.
    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.
    Takman, Per
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    First application experiments with the Stockholm compact soft x-ray microscope2009Inngår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 186Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Most soft x-ray microscopes operating in the water window (lambda = 2.3 - 4.4 nm) rely on synchrotron radiation sources. In the future we believe scientists will use soft x-ray microscopes as one imaging tool among others in their own laboratory. For this purpose we have developed a full field soft x-ray microscope with a laser-plasma source compact enough to fit on an optical table. In this contribution we describe the current status of this microscope now featuring stable operation at lambda = 3.37 nm or lambda = 2.48 nm. In-house fabricated single element zone plates offering the possibility to perform phase contrast imaging have been implemented. We also report on the first application experiments for compact soft x-ray microscopy, including results from studies of clay minerals and colloids existing in nature and results from phase optics experiments. Planned upgrades of the microscope include increasing the source brightness, implementing more efficient condenser optics, and installing a cryo sample stage for tomography. These improvements will open up for further applications, especially in the field of biological imaging.

  • 15.
    Bertilson, Michael
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    von Hofsten, Olov
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Holmberg, Anders
    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.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Laboratory soft-x-ray microscope for cryotomography of biological specimens2011Inngår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 36, nr 14, s. 2728-2730Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Soft-x-ray cryotomography allows quantitative and high-resolution three-dimensional imaging of intact unstained cells. To date, the method relies on synchrotron-radiation sources, which limits accessibility for researchers. Here we present a laboratory water-window microscope for cryotomography. It is based on a lambda = 2.48nm liquid-jet laser-plasma source, a normal-incidence multilayer condenser, a 30nm zone-plate objective, and a cryotilt sample holder. We demonstrate high-resolution imaging, as well as quantitative tomographic imaging, of frozen intact cells. The reconstructed tomogram of the intracellular local absorption coefficient shows details down to similar to 100nm.

  • 16.
    Bertilson, Michael
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    von Hofsten, Olov
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Christakou, Athanasia
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Jerlström-Hultqvist, J.
    Svärd, S.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Laboratory Soft X-Ray Cryo TomographyManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    X-rays allow quantitative high-spatial-resolution three-dimensional (3D) imaging of intact unstained cells. Such 3D imaging is provided by soft x-ray lens-based methods (water-window cryo tomography) and hard x-ray lens-less methods (coherent diffraction imaging) are emerging. However, both methods rely on high-brightness synchrotron-radiation sources, which limit the accessibility of a wider scientific community. Here we show 3D water-window cryo tomography with a laboratory-source-based microscope arrangement. The system relies on a λ=2.48-nm liquid-jet laser-plasma source, normal- incidence multilayer condenser optics, 30-nm zone-plate optics, and a cryo sample chamber. We demonstrate imaging of intact unstained yeast, protozoan parasites and mammalian cells. 3D images show noise-limited features close to ~100 nm and intra-cellular structure is classified based on the local absorption coefficient. A comprehensive theoretical model of the tomographic imaging system allows optimization of system parameters and a quantitative estimate of the 3D imaging accuracy. The model includes issues such as non-geometric projections of the thick samples and stray light, and is applicable to laboratory as well as synchrotron-based x-ray microscopes. The model shows that laboratory x-ray cryo tomography will allow quantitative 3D imaging with ~30-nm (half-period) resolution over a full 5 µm object.

     

  • 17.
    Bertilsson, Michael
    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.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Laboratory arrangement for soft x-ray zone-plate efficiency measurements2007Inngår i: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 78, nr 2, s. 026103-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate a laboratory-scale arrangement for rapid and accurate measurements of the absolute and local efficiency of soft x-ray micro zone plates in the water window. This in-house instrument is based on a single-line lambda=2.88 nm liquid-jet laser-plasma source. Measurements are performed by a simultaneous comparison of first diffraction-order photon flux with the flux in a calibrated reference signal. This arrangement eliminates existing source emission fluctuations. The performance of the method is demonstrated by the result from measurements of two similar to 55 mu m diameter nickel micro zone plates, showing a groove efficiency of 12.9%+/- 1.1% and 11.7%+/- 1.0%. Furthermore, we show that spatially resolved efficiency mapping is an effective tool for a detailed characterization of local zone plate properties. Thus, this laboratory-scale instrument allows rapid feedback to the fabrication process which is important for future improvements.

  • 18. Beye, Martin
    et al.
    Oberg, Henrik
    Xin, Hongliang
    Dakovski, Georgi L.
    Dell'Angela, Martina
    Foehlisch, Alexander
    Gladh, Jorgen
    Hantschmann, Markus
    Hieke, Florian
    Kaya, Sarp
    Kuehn, Danilo
    LaRue, Jerry
    Mercurio, Giuseppe
    Minitti, Michael P.
    Mitra, Ankush
    Moeller, Stefan P.
    Ng, May Ling
    Nilsson, Anders
    Nordlund, Dennis
    Norskov, Jens
    Ostrom, Henrik
    Ogasawara, Hirohito
    Persson, Mats
    Schlotter, William F.
    Sellberg, Jonas A.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wolf, Martin
    Abild-Pedersen, Frank
    Pettersson, Lars G. M.
    Wurth, Wilfried
    Chemical Bond Activation Observed with an X-ray Laser2016Inngår i: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 7, nr 18, s. 3647-3651Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The concept of bonding and antibonding orbitals is fundamental in chemistry. The population of those orbitals and the energetic difference between the two reflect the strength of the bonding interaction. Weakening the bond is expected to reduce this energetic splitting, but the transient character of bond-activation has so far prohibited direct experimental access. Here we apply time-resolved soft X-ray spectroscopy at a free electron laser to directly observe the decreased bonding antibonding splitting following bond-activation using an ultrashort optical laser pulse.

  • 19.
    Bielecki, Johan
    et al.
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Husargatan 3,Box 596, SE-75124 Uppsala, Sweden.;European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Svenda, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Husargatan 3,Box 596, SE-75124 Uppsala, Sweden.
    Sellberg, Jonas A.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Husargatan 3,Box 596, SE-75124 Uppsala, Sweden.
    Maia, Filipe R. N. C.
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Husargatan 3,Box 596, SE-75124 Uppsala, Sweden.;Lawrence Berkeley Natl Lab, NERSC, Berkeley, CA 94720 USA..
    Electrospray sample injection for single-particle imaging with x-ray lasers2019Inngår i: Science Advances, E-ISSN 2375-2548, Vol. 5, nr 5, artikkel-id eaav8801Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The possibility of imaging single proteins constitutes an exciting challenge for x-ray lasers. Despite encouraging results on large particles, imaging small particles has proven to be difficult for two reasons: not quite high enough pulse intensity from currently available x-ray lasers and, as we demonstrate here, contamination of the aerosolized molecules by nonvolatile contaminants in the solution. The amount of contamination on the sample depends on the initial droplet size during aerosolization. Here, we show that, with our electrospray injector, we can decrease the size of aerosol droplets and demonstrate virtually contaminant-free sample delivery of organelles, small virions, and proteins. The results presented here, together with the increased performance of next-generation x-ray lasers, constitute an important stepping stone toward the ultimate goal of protein structure determination from imaging at room temperature and high temporal resolution.

  • 20. Blomqvist, M.
    et al.
    Pålsson, M.
    Blomster, O.
    Manneberg, Göran
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Fundamental-mode fiber-to-fiber coupling at high-power2009Inngår i: Solid State Lasers XVIII: Technology and Devices, SPIE - International Society for Optical Engineering, 2009, s. 71930F-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Fiber-to-fiber coupling between two different fibers is a state of the art technology. Products are available on the market where multimode fibers can be coupled with very low power loss, at very high powers (multi-kilowatt). We have, however, always been forced to accept a certain loss in beam quality, manifesting as an increase in the Beam Parameter Product (BPP). In fundamental-mode fiber-to-fiber coupling no beam quality is lost. We instead expect to have a certain power loss in the coupling. This paper addresses the problems in free-space fundamental-mode fiber-to-fiber coupling, including theoretical estimations of expected power loss, estimated demands on the stability of the optics as well as measured values on a fundamental mode fiber-to-fiber coupler. The theoretical calculations of the sensitivity of the coupling efficiency due to radial misalignment and defocus (longitudinal displacement) have been confirmed experimentally. Experimental results at 100 W laser power include 88% coupling efficiency using a large mode area fiber with mode-field diameter (MFD) of 18 μm and 75 % coupling efficiency using a single-mode fiber with MFD of 6.4 μm.

  • 21. Bruus, Henrik
    et al.
    Dual, Jürg
    Hawkes, Jeremy
    Hill, Martyn
    Laurell, Thomas
    Nilsson, Johan
    Radel, Stefan
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Forthcoming lab on a chip tutorial series on acoustofluidics: Acoustofluidics - Exploiting ultrasonic standing wave forces and acoustic streaming in microfluidic systems for cell and particle manipulation2011Inngår i: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 11, nr 21, s. 3579-3580Artikkel i tidsskrift (Annet vitenskapelig)
  • 22. Bucht, C.
    et al.
    Söderberg, P.
    Manneberg, Göran
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Fully automated corneal endothelial morphometry of images captured by clinical specular microscopy2009Inngår i: Ophthalmic Technologies XIX, SPIE - International Society for Optical Engineering, 2009, s. 716315-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The corneal endothelium serves as the posterior barrier of the cornea. Factors such as clarity and refractive properties of the cornea are in direct relationship to the quality of the endothelium. The endothelial cell density is considered the most important morphological factor. Morphometry of the corneal endothelium is presently done by semi-automated analysis of pictures captured by a Clinical Specular Microscope (CSM). Because of the occasional need of operator involvement, this process can be tedious, having a negative impact on sampling size. This study was dedicated to the development of fully automated analysis of images of the corneal endothelium, captured by CSM, using Fourier analysis. Software was developed in the mathematical programming language Matlab. Pictures of the corneal endothelium, captured by CSM, were read into the analysis software. The software automatically performed digital enhancement of the images. The digitally enhanced images of the corneal endothelium were transformed, using the fast Fourier transform (FFT). Tools were developed and applied for identification and analysis of relevant characteristics of the Fourier transformed images. The data obtained from each Fourier transformed image was used to calculate the mean cell density of its corresponding corneal endothelium. The calculation was based on well known diffraction theory. Results in form of estimated cell density of the corneal endothelium were obtained, using fully automated analysis software on images captured by CSM. The cell density obtained by the fully automated analysis was compared to the cell density obtained from classical, semiautomated analysis and a relatively large correlation was found.

  • 23. Bucht, C.
    et al.
    Söderberg, P.
    Manneberg, Göran
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Fully automated corneal endothelial morphometry of images captured by clinical specular microscopy2010Inngår i: Ophthalmic Technologies XX, SPIE - International Society for Optical Engineering, 2010, s. 75501E-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The corneal endothelium serves as the posterior barrier of the cornea. Factors such as clarity and refractive properties of the cornea are in direct relationship to the quality of the endothelium. The endothelial cell density is considered the most important morphological factor of the corneal endothelium. Pathological conditions and physical trauma may threaten the endothelial cell density to such an extent that the optical property of the cornea and thus clear eyesight is threatened. Diagnosis of the corneal endothelium through morphometry is an important part of several clinical applications. Morphometry of the corneal endothelium is presently carried out by semi automated analysis of pictures captured by a Clinical Specular Microscope (CSM). Because of the occasional need of operator involvement, this process can be tedious, having a negative impact on sampling size. This study was dedicated to the development and use of fully automated analysis of a very large range of images of the corneal endothelium, captured by CSM, using Fourier analysis. Software was developed in the mathematical programming language Matlab. Pictures of the corneal endothelium, captured by CSM, were read into the analysis software. The software automatically performed digital enhancement of the images, normalizing lights and contrasts. The digitally enhanced images of the corneal endothelium were Fourier transformed, using the fast Fourier transform (FFT) and stored as new images. Tools were developed and applied for identification and analysis of relevant characteristics of the Fourier transformed images. The data obtained from each Fourier transformed image was used to calculate the mean cell density of its corresponding corneal endothelium. The calculation was based on well known diffraction theory. Results in form of estimated cell density of the corneal endothelium were obtained, using fully automated analysis software on 292 images captured by CSM. The cell density obtained by the fully automated analysis was compared to the cell density obtained from classical, semiautomated analysis and a relatively large correlation was found.

  • 24.
    Bucht, Curry
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Söderberg, P.
    Manneberg, Göran
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    A model for corneal endothelial morphometry by diffraction2006Inngår i: Progr. Biomed. Opt. Imaging Proc. SPIE, 2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    As a part of an ongoing project on corneal endothelium morphometry by diffraction, a model for corneal endothelium simulation has been developed. The model has been developed in the mathematical programming language Matlab™. Images of corneal endothelium were simulated and the diffraction pattern of the image was calculated. The diffraction pattern was calculated for a series of endothelial images while varying important variables in the simulated image. This rendered the theoretical relationships between values of variables in the diffraction pattern and values of morphometric variables in the image. At this stage, the analysis focused on the expression of endothelial mean cell size and coefficient of variation in the diffraction pattern, respectively. As expected from diffraction theory, it was found that there is a direct linear relationship between mean cell size and distance between periodic variations in the diffraction pattern. We further found that the ratio between the intensity in the central maximum and the intensity in the first harmonic of the diffraction pattern was functionally depending on the variation in cell size. The current findings demonstrate that it is possible to theoretically determine average cell size and coefficient of variation of cell size in the diffraction pattern.

  • 25.
    Bucht, Curry
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. Karolinska Institutet, Sweden.
    Söderberg, P.
    Manneberg, Göran
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Recording the diffraction pattern reflected from corneal endothelium2007Inngår i: Ophthalmic Technologies XVII, SPIE - International Society for Optical Engineering, 2007, s. 42610-42610Konferansepaper (Fagfellevurdert)
    Abstract [en]

    As a part of an ongoing research project on morphometrical diagnosis of the corneal endothelium, an experimental optical setup has been created. The structure of the corneal endothelial cells could be considered a reflecting periodical aperture. Hence, the diffraction pattern reflected from the endothelium contains valuable morphometrical information. In the present work, focus has been on sampling the posterior surface of explanted corneas. Methods: An optical setup was created, using a 632.8 nm He-Ne laser as the light source. The desired diffraction pattern was produced as a collimated reflection. Hence, because the posterior surface of the cornea is concave, lenses were used to attain the right divergence of the light impingent on the corneal endothelium. These lenses also made it possible to adjust the sampling spot size. A beam splitter (BS) was used to provide an optical path for both the impinging laser beam as well as the reflected diffracted beam. The lens acting as a Fourier lens was then placed after the BS. At the back focal plane of the Fourier lens, a CCD detector was used for recording in the Fourier plane. In the process of creating the setup, explanted corneas were emulated using grated contact lenses. Results: The current optical set up allows identification of a diffraction pattern from a concave spherical surface with a radius of curvature of the same order as a human cornea.

  • 26.
    Bucht, Curry
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Söderberg, P.
    Manneberg, Göran
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    The impact of horizontal offset of the cornea during corneal specular microscopy2008Inngår i: Progr. Biomed. Opt. Imaging Proc. SPIE, 2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We are developing automated morphometric analysis of the corneal endothelium. Here, the general impact of horizontal offset of the cornea on morphometry was examined. Errors due to perspective during imaging with a Clinical Specular Microscope (CSM) were analyzed considering semi automated analysis software and fully automated Fourier analysis software. Methods: A mathematical model of the cornea was created. Trigonometry was applied to find the relationship between the horizontal offset of the cornea relative to the microscope objective, and the consecutive errors from perspective changes in the image. An experimental setup was created using a cornea made of polymethyl methacrylate (PMMA). The posterior surface of the PMMA cornea was horizontally marked. The PMMA cornea was placed in a holder. Difference in refractive index between real endothelium and aqueous humor was emulated using high refractive index liquid. Images with varying horizontal offset on the PMMA corneal posterior surface, along with their relative offset coordinates were captured, using CSM. Results: Experiments using controlled offset of the cornea in relation to its center estimated that analyzable images can be acquired within an interval of 1.26 mm, using central cornea sampling CSM. Because of refractive indices along with light scattering differences between the corneal tissue and PMMA , the 1.26 mm interval should be considered a first estimate for feasible CSM images. The effect of corneal endothelial offset during imaging with CSM or fully automated Fourier analysis should be considered.

  • 27.
    Bucht, Curry
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Söderberg, Per
    Manneberg, Göran
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Simulation of specular microscopy images of corneal endothelium, a tool for control of measurement errors2011Inngår i: ACTA OPHTHALMOLOGICA, ISSN 1755-375X, Vol. 89, nr 3, s. e242-e250Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: We aimed at developing simulation software capable of producing images of corneal endothelium close to identical to images captured by clinical specular microscopy with defined morphometrical characteristics. It was further planned to demonstrate the usefulness of the simulator by analysing measurement errors associated with a trained operator using a commercially available semi-automatic algorithm for analysis of simulated images. Methods: Software was developed that allows creation of unique images of the corneal endothelium expressing morphology close to identical with that seen in images of corneal specular microscopy. Several hundred unique images of the corneal endothelium were generated with randomization, spanning a physiological range of endothelial cell density. As an example of the usefulness of the simulator for analysis of measurement errors in corneal specular microscopy, a total of 12 of all the images generated were randomly selected such that the endothelial cell density expressed was evenly distributed over the physiological range of endothelial cell density. The images were transferred to a personal computer. The imagenet-640 software was used to analyse endothelial cell size variation, percentage of hexagonal endothelial cells, and endothelial cell density. Results: The simulator developed allows randomized generation of corneal specular microscopy images with a preset expected average and variation of cell structure. Calculated morphometric information of each cell is stored in the simulator. The image quality can secondarily be varied with a toolbox of filters to approximate a large spectrum of clinically captured images. As an example of the use of the simulator, measurement errors associated with one trained operator using the imagenet-640 software, and focusing on endothelial cell density, were examined. The functional dependence between morphometric information estimated with the imagenet-640 software algorithm and real morphometric information as provided by the simulator was analysed with regression. It was demonstrated that that the estimations of endothelial cell size variation was associated with a scaling error and that the random error was strongly dependent on the operator. Conclusion: The newly developed simulator for randomized generation of morphometrically defined corneal specular microscopy images for the first time makes it possible to estimate a spatial scaling error of an available semi-automatic algorithm and to determine the random measurement error of important morphometric estimates in a defined reference sample of images. It is anticipated that the simulator will be a valuable tool for the generation of a large set of morphometrically well-characterized corneal specular microscopy images that can be used for calibration among research centres, for minimization of random errors and for measurement of quality control. Simulated images will be useful for the development of fully automatic analysis of corneal endothelial cell morphometry.

  • 28.
    Burvall, Anna
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Barrett, Harrison H.
    Myers, Kyle J.
    Dainty, Christopher
    Singular-value decomposition of a tomosynthesis system2010Inngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 18, nr 20, s. 20699-20711Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tomosynthesis is an emerging technique with potential to replace mammography, since it gives 3D information at a relatively small increase in dose and cost. We present an analytical singular-value decomposition of a tomosynthesis system, which provides the measurement component of any given object. The method is demonstrated on an example object. The measurement component can be used as a reconstruction of the object, and can also be utilized in future observer studies of tomosynthesis image quality.

  • 29.
    Burvall, Anna
    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.
    Lundström, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Stig, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Hallström, Stefan
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Phase-retrieval methods with applications in composite-material tomography2013Inngår i: 11th International Conference On X-Ray Microscopy (XRM2012), Institute of Physics Publishing (IOPP), 2013, s. 012015-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In-line phase-contrast x-ray imaging is emerging as a method for observing small details when the contrast in absorption x-ray imaging is low. It gives images with strong edge enhancement, and phase retrieval is necessary to obtain quantitative thickness information. In particular for tomography, clarity can be enhanced by phase retrieval, as here demonstrated on a 3D-weave reinforced composite material. Seven suitable phase-retrieval methods are identified and integrated into a single method, where each version is marked by variations in particular steps. The general method and its variations are outlined and a comparison shows which methods are most suitable in different situations.

  • 30.
    Burvall, Anna
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lundstrom, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Takman, Per A. C.
    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.
    Phase retrieval in X-ray phase-contrast imaging suitable for tomography2011Inngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 19, nr 11, s. 10359-10376Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In-line phase-contrast X-ray imaging provides images where both absorption and refraction contribute. For quantitative analysis of these images, the phase needs to be retrieved numerically. There are many phase-retrieval methods available. Those suitable for phase-contrast tomography, i.e., non-iterative phase-retrieval methods that use only one image at each projection angle, all follow the same pattern though derived in different ways. We outline this pattern and use it to compare the methods to each other, considering only phase-retrieval performance and not the additional effects of tomographic reconstruction. We also outline derivations, approximations and assumptions, and show which methods are similar or identical and how they relate to each other. A simple scheme for choosing reconstruction method is presented, and numerical phase-retrieval performed for all methods.

  • 31.
    Burvall, Anna
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. KTH, Skolan för bioteknologi (BIO), Centra, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Lundström, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. KTH, Skolan för bioteknologi (BIO), Centra, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Takman, Per
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. KTH, Skolan för bioteknologi (BIO), Centra, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Larsson, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. KTH, Skolan för bioteknologi (BIO), Centra, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Hertz, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. KTH, Skolan för bioteknologi (BIO), Centra, Albanova VinnExcellence Center for Protein Technology, ProNova.
    X-ray in-line phase retrieval for tomography2012Inngår i: Progress in Biomedical Optics and Imaging - Proceedings of SPIE, SPIE - International Society for Optical Engineering, 2012, Vol. 8313, s. 83136A-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Phase contrast in X-ray imaging offers imaging of fine features at lower doses than absorption. Of the phasecontrast methods in use in-line phase contrast is interesting due to its experimental simplicity, but to extract information on absorption and phase distributions from the resulting images, phase retrieval is needed. Many phase-retrieval methods suitable for different situations have been developed, but few comparisons of those methods done. We consider a sub-group of phase-retrieval methods that are suitable for tomography, i.e., that use only one exposure (for practical experimental reasons) and are non-iterative (for speed). In total we have found seven suitable methods in the literature. All, though derived in different ways under different assumptions, follow the same pattern and can be outlined as a single method where each specific version is marked by variations in particular steps. We summarize this unified approach, and give the variations of the individual methods. In addition, we outline approximations and assumptions of each method. Using this approach it is possible to conclude which specific algorithms are most suitable in specific situations and to test this based on simulated and experimental data. Ultimately, this leads to conclusions on which methods are the most suitable in different situations.

  • 32.
    Christakou, Athanasia
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ultrasound-assisted Interactions of Natural Killer Cells with Cancer Cells and Solid Tumors2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    In this Thesis, we have developed a microtechnology-based method for culturing and visualizing high numbers of individual cells and cell-cell interactions over extended periods of time. The foundation of the device is a silicon-glass multiwell microplate (also referred as microchip) directly compatible with fluorescence microscopy. The initial microchip design involved thousands of square wells of sizes up to 80 µm, for screening large numbers of cell-cell interactions at the single cell level. Biocompatibility and confinement tests proved the feasibility of the idea, and further investigation showed the conservation of immune cellular processes within the wells. Although the system is very reliable for screening, limitations related to synchronization of the interaction events, and the inability to maintain conjugations for long time periods, led to the development of a novel ultrasonic manipulation multiwell microdevice.

    The main components of the ultrasonic device is a 100-well silicon-glass microchip and an ultrasonic transducer. The transducer is used for ultrasonic actuation on the chip with a frequency causing half-wave resonances in each of the wells (2.0-2.5 MHz for wells with sizes 300-350 µm). Therefore, cells in suspension are directed by acoustic radiation forces towards a pressure node formed in the center of each well. This method allows simultaneous aggregation of cells in all wells and sustains cells confined within a small area for long time periods (even up to several days).

    The biological target of investigation in this Thesis is the natural killer (NK) cells and their functional properties. NK cells belong to the lymphatic group and they are important factors for host defense and immune regulation. They are characterized by the ability to interact with virus infected cells and cancer cells upon contact, and under suitable conditions they can induce target cell death. We have utilized the ultrasonic microdevice to induce NK-target cell interactions at the single cell level. Our results confirm a heterogeneity within IL-2 activated NK cell populations, with some cells being inactive, while others are capable to kill quickly and in a consecutive manner.

    Furthermore, we have integrated the ultrasonic microdevice in a temperature regulation system that allows to actuate with high-voltage ultrasound, but still sustain the cell physiological temperature. Using this system we have been able to induce formation of up to 100 solid tumors (HepG2 cells) in parallel without using surface modification or hydrogels. Finally, we used the tumors as targets for investigating NK cells ability to infiltrate and kill solid tumors. 

    To summarize, a method is presented for investigating individual NK cell behavior against target cells and solid tumors. Although we have utilized our technique to investigate NK cells, there is no limitation of the target of investigation. In the future, the device could be used for any type of cells where interactions at the single cell level can reveal critical information, but also to form solid tumors of primary cancer cells for toxicology studies.

  • 33.
    Christakou, Athanasia E.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ohlin, Mathias
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vanherberghen, Bruno
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Khorshidi, Mohammad Ali
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Kadri, Nadir
    Frisk, Thomas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Önfelt, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Live cell imaging in a micro-array of acoustic traps facilitates quantification of natural killer cell heterogeneity2013Inngår i: Integrative Biology, ISSN 1757-9694, E-ISSN 1757-9708, Vol. 5, nr 4, s. 712-719Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Natural killer (NK) cells kill virus-infected or cancer cells through the release of cytotoxic granules into a tight intercellular contact. NK cell populations comprise individual cells with varying sensitivity to distinct input signals, leading to disparate responses. To resolve this NK cell heterogeneity, we have designed a novel assay based on ultrasound-assisted cell-cell aggregation in a multiwell chip allowing high-resolution time-lapse imaging of one hundred NK-target cell interactions in parallel. Studying human NK cells' ability to kill MHC class I deficient tumor cells, we show that approximately two thirds of the NK cells display cytotoxicity, with some NK cells being particularly active, killing up to six target cells during the assay. We also report that simultaneous interaction with several susceptible target cells increases the cytotoxic responsiveness of NK cells, which could be coupled to a previously unknown regulatory mechanism with implications for NK-mediated tumor elimination.

  • 34.
    Christakou, Athanasia E.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Ohlin, Mathias
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Önfelt, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Solid tumor spheroid formation by temperature-controlled high voltage ultrasound in a multi-well microdevice2014Inngår i: 18th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2014, Chemical and Biological Microsystems SocietyChemical and Biological Microsystems Society , 2014, s. 573-575Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In the present work we demonstrate effective 3D growth of human hepatocellular carcinoma (HCC) HepG2 cell spheroids in parallel in a multi-well microdevice actuated with high voltage ultrasound in a temperature-controlled system. We compare the spheroid formation during continuous ultrasound exposure for one week where we formed spheroids in 59% of the wells, with the spheroid formation without ultrasound actuation, where we obtained 0% spheroids. Furthermore, we present an application of the tumor spheroids for investigating natural killer (NK) cells behavior against solid tumors.

  • 35.
    Christakou, Athanasia E.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ohlin, Mathias
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Önfelt, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ultrasonic three-dimensional cell culture on chip for dynamic studies of tumor immune surveillance by natural killer cellsManuskript (preprint) (Annet vitenskapelig)
  • 36.
    Christakou, Athanasia E.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ohlin, Mathias
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Önfelt, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ultrasound-assisted three-dimensional tumor formation in a multi well microplate for monitoring natural killer cell functional behaviorManuskript (preprint) (Annet vitenskapelig)
  • 37.
    Christakou, Athanasia
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ohlin, Mathias
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Önfelt, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik. Karolinska Inst, Dept Microbiol Tumor & Cell Biol, Stockholm, Sweden.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ultrasonic three-dimensional on-chip cell culture for dynamic studies of tumor immune surveillance by natural killer cells2015Inngår i: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 15, nr 15, s. 3222-31Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate a simple method for three-dimensional (3D) cell culture controlled by ultrasonic standing waves in a multi-well microplate. The method gently arranges cells in a suspension into a single aggregate in each well of the microplate and, by this, nucleates 3D tissue-like cell growth for culture times between two and seven days. The microplate device is compatible with both high-resolution optical microscopy and maintenance in a standard cell incubator. The result is a scaffold- and coating-free method for 3D cell culture that can be used for controlling the cellular architecture, as well as the cellular and molecular composition of the microenvironment in and around the formed cell structures. We demonstrate the parallel production of one hundred synthetic 3D solid tumors comprising up to thousands of human hepatocellular carcinoma (HCC) HepG2 cells, we characterize the tumor structure by high-resolution optical microscopy, and we monitor the functional behavior of natural killer (NK) cells migrating, docking and interacting with the tumor model during culture. Our results show that the method can be used for determining the collective ability of a given number of NK cells to defeat a solid tumor having a certain size, shape and composition. The ultrasound-based method itself is generic and can meet any demand from applications where it is advantageous to monitor cell culture from production to analysis of 3D tissue or tumor models using microscopy in one single microplate device.

  • 38.
    Chubarova, Elena
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Nilsson, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lindblom, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Reinspach, Julia
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Birch, Jens
    Department of Physics, Chemistry, and Biology, Linköping University.
    Vogt, Ulrich
    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.
    Platinum zone plates for hard X-ray applications2011Inngår i: Microelectronic Engineering, ISSN 0167-9317, E-ISSN 1873-5568, Vol. 88, nr 10, s. 3123-3126Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We describe the fabrication and evaluation of platinum zone plates for 5–12 kV X-ray imaging and focusing. These nano-scale circular periodic structures are fabricated by filling an e-beam generated mold with Pt in an electroplating process. The plating recipe is described. The resulting zone plates, having outer zone widths of 100 and 50 nm, show good uniformity and high aspect ratio. Their diffraction efficiencies are 50–70% of the theoretical, as measured at the European Synchrotron Radiation Facility. Platinum shows promise to become an attractive alternative to present hard X-ray zone plate materials due to its nano-structuring properties and the potential for zone-plate operation at higher temperatures.

  • 39.
    Chubarova, Elena V.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. Jacobs Univ, Sch Sci & Engn, Germany.
    Dickman, M. H.
    Keita, B.
    Nadjo, L.
    Miserque, F.
    Mifsud, M.
    Arends, I. W. C. E.
    Kortz, U.
    Self-assembly of a heteropolyoxopalladate nanocube: [PdII 13AsV 8O34(OH)6] 8-2008Inngår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 47, nr 49, s. 9542-9546Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    (Chemical Equation Presented) Not like the others: A molecular palladium oxide cluster was formed by self-assembly of palladium(II) and arsenic(V) using mild reaction conditions. The resulting heteropolypalladate [Pd II 13AsV 8O34(OH) 6]8- has a distorted cubic shape and edge lengths of about 1 nm. The thirteen PdII ions retain four-coordinate square-planar geometry, in marked contrast to all other known discrete polyoxometalates.

  • 40. Corrigan, S.
    et al.
    Zon, G. D. R.
    Maij, A.
    McDonald, Nick J.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Mårtensson, Lena K.
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekonomi och organisation (Inst.).
    An approach to collaborative learning and the serious game development2015Inngår i: Cognition, Technology & Work, ISSN 1435-5558, E-ISSN 1435-5566, Vol. 17, nr 2, s. 269-278Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents the overall learning process that evolved during the MASCA project (MAnaging System Change in Aviation—EU FP7 funded project (2010–2013), specifically focusing on the one of the key elements of the overall learning approach, the development of a serious game (SKYBOARD) and the role the game played in supporting the implementation of airport collaborative decision-making (A-CDM) in a major European airport. The underlying principles of the learning process was based on ongoing and collaborative learning in the workplace, with each phase of learning involving preparation and guidance, collaborative learning, consolidation of that learning and practically focused next steps that can be deployed to support overall change management. The aim of SKYBOARD was to aid communication and collaboration when introducing A-CDM, and thereby supporting the cultural change that comes with this introduction. The development of SKYBOARD was based upon an initial training needs analysis and an iterative development and implementation approach at a major European airport. The research demonstrated that we are at the beginning of a fundamental shift in the way both learning and working is happening in organisations. Therefore, the establishment of a collaborative learning process and integrated learning package needs to focus on supporting continuous performance improvement and learning (competency and capability at all levels) and to ensure this overall learning is fully aligned to the overall strategic blueprint of the organisation. The evaluation of SKYBOARD demonstrated that serious games can support collaborative learning and enhanced communication and that such games should be key resource in any learning environment and proved to be a highly effective support to the implementation of A-CDM in this case.

  • 41.
    Daemi, Bita
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    How to measure the Transverse Chromatic Aberration of the human eye in off-axis angels2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Peripheral vision plays an important role for visually impaired people with central field loss. Furthermore, recent studies show that defocus in the image on the peripheral retina might influence the development of myopia. Apart from the refractive errors and astigmatism, off-axis aberrations such as coma and transverse chromatic aberration (TCA) also influence the image quality on the peripheral retina. Theory shows that the amount of TCA is quite large in peripheral vision especially in large off-axis angles. The aim of this study is to develop a method to measure the amount of TCA in the peripheral field of view of the human eye.

    The method which was used for this study was subjective and the amount of TCA was measured in the left eye of the three volunteer adult subjects. The method was based on measuring the TCA as a chromatic difference of position outside of the eye. The measurements were done in the nasal retina of the eye in seven angles from 0 deg eccentricity (fovea) to 60 deg eccentricity. To compare the experimental results with theoretical values two schematic eye models were implemented in ZEMAX optical design software; a reduced eye model and a wide angle eye model.

    The results showed the expected increase of TCA with off-axis angle. The measurements for two subjects were in good agreement with the eye models. The magnitudes for TCA varied between subjects, one reason for this can be related to the different shapes of the eye in different subjects. The third subject had different values for TCA. This difference led us to investigate the reliability and the repeatability of the method in more detail.

  • 42. Daniel, Salman
    et al.
    Saastamoinen, Kimmo
    Saastamoinen, Toni
    Rahomaki, Jussi
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Friberg, Ari T.
    Visser, Taco D.
    Dynamic control of optical transmission through a nano-slit using surface plasmons2015Inngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 23, nr 17, s. 22512-22519Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate how the optical transmission by a directly illuminated, sub-wavelength slit in a metal film can be dynamically controlled by varying the incident beam's phase relative to that of a stream of surface plasmon polaritions which are generated at a nearby grating. The transmission can be smoothly altered from its maximum value to practically zero. The results from a simple model and from rigorous numerical simulations are in excellent agreement with our experimental results. Our method may be applied in all-optical switching.

  • 43. Daurer, Benedikt J.
    et al.
    Okamoto, Kenta
    Bielecki, Johan
    Maia, Filipe R. N. C.
    Muhlig, Kerstin
    Seibert, M. Marvin
    Hantke, Max F.
    Nettelblad, Carl
    Benner, W. Henry
    Svenda, Martin
    Timneanu, Nicusor
    Ekeberg, Tomas
    Loh, N. Duane
    Pietrini, Alberto
    Zani, Alessandro
    Rath, Asawari D.
    Westphal, Daniel
    Kirian, Richard A.
    Awel, Salah
    Wiedorn, Max O.
    van der Schot, Gijs
    Carlsson, Gunilla H.
    Hasse, Dirk
    Sellberg, Jonas A.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Barty, Anton
    Andreasson, Jakob
    Boutet, Sebastian
    Williams, Garth
    Koglin, Jason
    Andersson, Inger
    Hajdu, Janos
    Larsson, Daniel S. D.
    Experimental strategies for imaging bioparticles with femtosecond hard X-ray pulses2017Inngår i: IUCrJ, ISSN 0972-6918, E-ISSN 2052-2525, Vol. 4, s. 251-262Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study explores the capabilities of the Coherent X-ray Imaging Instrument at the Linac Coherent Light Source to image small biological samples. The weak signal from small samples puts a significant demand on the experiment. Aerosolized Omono River virus particles of similar to 40 nm in diameter were injected into the submicrometre X-ray focus at a reduced pressure. Diffraction patterns were recorded on two area detectors. The statistical nature of the measurements from many individual particles provided information about the intensity profile of the X-ray beam, phase variations in the wavefront and the size distribution of the injected particles. The results point to a wider than expected size distribution (from similar to 35 to similar to 300 nm in diameter). This is likely to be owing to nonvolatile contaminants from larger droplets during aerosolization and droplet evaporation. The results suggest that the concentration of nonvolatile contaminants and the ratio between the volumes of the initial droplet and the sample particles is critical in such studies. The maximum beam intensity in the focus was found to be 1.9 * 10(12) photons per mu m(2) per pulse. The full-width of the focus at half-maximum was estimated to be 500 nm (assuming 20% beamline transmission), and this width is larger than expected. Under these conditions, the diffraction signal from a sample-sized particle remained above the average background to a resolution of 4.25 nm. The results suggest that reducing the size of the initial droplets during aerosolization is necessary to bring small particles into the scope of detailed structural studies with X-ray lasers.

  • 44.
    Delsing, Per
    et al.
    Chalmers Univ Technol, Microtechnol & Nanosci, S-41296 Gothenburg, Sweden..
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Westerhausen, Christoph
    Univ Augsburg, Inst Phys, D-86159 Augsburg, Germany.;NIM, Munich, Germany.;Ludwig Maximilians Univ Munchen, Ctr NanoSci CeNS, D-80799 Munich, Germany.;Univ Augsburg, Ctr Interdisciplinary Hlth Res ZIG, D-86135 Augsburg, Germany.;ACIT, D-86159 Augsburg, Germany..
    The 2019 surface acoustic waves roadmap2019Inngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 52, nr 35, artikkel-id 353001Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Today, surface acoustic waves (SAWs) and bulk acoustic waves are already two of the very few phononic technologies of industrial relevance and can been found in a myriad of devices employing these nanoscale earthquakes on a chip. Acoustic radio frequency filters, for instance, are integral parts of wireless devices. SAWs in particular find applications in life sciences and microfluidics for sensing and mixing of tiny amounts of liquids. In addition to this continuously growing number of applications, SAWs are ideally suited to probe and control elementary excitations in condensed matter at the limit of single quantum excitations. Even collective excitations, classical or quantum are nowadays coherently interfaced by SAWs. This wide, highly diverse, interdisciplinary and continuously expanding spectrum literally unites advanced sensing and manipulation applications. Remarkably, SAW technology is inherently multiscale and spans from single atomic or nanoscopic units up even to the millimeter scale. The aim of this Roadmap is to present a snapshot of the present state of surface acoustic wave science and technology in 2019 and provide an opinion on the challenges and opportunities that the future holds from a group of renown experts, covering the interdisciplinary key areas, ranging from fundamental quantum effects to practical applications of acoustic devices in life science.

  • 45.
    Doddapaneni, Venkatesh
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Saleemi, Mohsin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Ye, Fei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Gati, R.
    Toprak, Muhammet Sadaka
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Engineered PMMA-ZnO nanocomposites for improving the electric arc interruption capability in electrical switching applications: Unprecedented experimental insights2017Inngår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 141, s. 113-119Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Polymer inorganic nanocomposites (PINCs) have been engineered for controlling the electrical arc and to improve the arc interruption capability of the electrical switching applications, like circuit breakers. Several PINCs are fabricated by formation of ZnO quantum dots (QDs) in a poly (methyl methacrylate) (PMMA) matrix via in-situ polymerization method to avoid agglomeration of QDs, leading to a good spatial distribution of QDs in the polymer matrix. These PINCs have been characterized in detail for the morphology of QDs, interaction between QDs and polymer matrix, and ultraviolet (UV) radiation absorption. ZnO QDs have been assessed to have particle diameter of 3.5 nm, and their presence in the PMMA is revealed by the unique luminescence characteristics of the QDs under UV light. The presence of ZnO QDs broadened the range of UV radiation absorption of PMMA and the absorption edge is gradually shifted from 270 nm to 338 nm with step-wise loading of ZnO QDs. The PINCs are tested to determine their reproducibility and impact on the electrical arcs of current 1.6 kA generated using a specially designed test-setup. Interaction of PINCs with the electrical arcs generates ablation of chemical species towards core of the electrical arc, resulting in increase of voltage leading to cool-down the arc temperature. This experimental study demonstrates for the first time that these PINCs are reproducible, reliable and provides superior arc interruption capability.

  • 46.
    Doddapaneni, Venkatesh
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Ye, Fei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Saleemi, Mohsin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Gati, Rudolf
    ABB Switzerland.
    Toprak, Muhammet Sadaka
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    New experimental insights for controlling the electrical arcs in electrical switching applications: a comparative study on PMMA nanocomposites of Au and ZnO2017Inngår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Polymer inorganic nanocomposites (PINCs) are developed, not only due to scientific interest but also improving theelectric arc interruption process in the electrical switching applications like circuit breakers. The novelty of this work isin integrating the current developments in PINCs into electrical switching application in order to extend the limits of thepower switching devices. Several PINCs are fabricated by using pre-synthesized Au nanoparticles (NPs) of size 2.75 ±0.4 nm and poly (methyl methacrylate) (PMMA) matrix via in-situ polymerization method. Six homogeneous PINCsamples with ultra-low wt% of Au NPs varying from 0.0003 to 0.005 wt% have been fabricated. We find that thepresence of Au NPs improved the convective heat transfer and visible optical radiation absorption of PMMA. Thefabricated PINCs are tested for their arc interruption performance and the results are compared with ZnO PINCs in ourearlier work. The results of the experiments insights demonstrate the impact of PINCs on the electrical arcs and theirpotential advantages of having PINCs for the electric arc interruption process in high power switching devices.

  • 47. Eilers, S.
    et al.
    Mårtensson, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Pettersson, H.
    Pillado, M.
    Gallegos, D.
    Tobar, M.
    Johansson, Karl Henrik
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Ma, Xiaoliang
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Transportplanering, ekonomi och teknik.
    Friedrichs, T.
    Borojeni, S. S.
    Adolfson, M.
    COMPANION-Towards Co-operative Platoon Management of Heavy-Duty Vehicles2015Inngår i: IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC, IEEE , 2015, s. 1267-1273Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The objective of the EU project COMPANION is to develop co-operative mobility technologies for supervised vehicle platooning, in order to improve fuel efficiency and safety for goods transport. The potential social and environmental benefits inducted by heavy-duty vehicle platoons have been largely proven. However, until now, the creation, coordination, and operation of such platoons have been mostly neglected. In addition, the regulation and standardization of coordinated platooning, together with its acceptance by the end-users and the society need further attention and research. In this paper we give an overview over the project and present the architecture of the off-board and onboard platforms of the COMPANION cooperative platoon management system. Furthermore, the consortium reports on the first results of the human factors for platooning, legislative analysis of platooning aspects, clustering and optimization of platooning plans and prediction of congestion due to planned special events. Finally, we present the method of validation of the system via simulation and trials.

  • 48.
    Faridi, Muhammad Asim
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab. mafaridi@kth.se.
    Ramachandraiah, Harisha
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Iranmanesh, Ida Sadat
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Grishenkov, Dmitry
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinsk bildteknik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Russom, Aman
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    MicroBubble Activated Acoustic Cell Sorting: BAACSInngår i: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Acoustophoresis, the ability to acoustically manipulate particles and cells inside a microfluidic channel, is a critical enabling technology for cell-sorting applications. However, one of the major impediments for routine use of acoustophoresis at clinical laboratory has been the reliance on the inherent physical properties of cells for separation. Here, we present a microfluidic-based microBubble-Activated Acoustic Cell Sorting (BAACS) method that rely on the specific binding of target cells to microbubbles conjugated with specific antibodies on their surface for continuous cell separation using ultrasonic standing wave. In acoustophoresis, cells being positive acoustic contrast particles migrate to pressure nodes. On the contrary we show that air-filled polymer-shelled microbubbles being strong negative acoustic contrast particles migrate to pressure antinodes at acoustic pressure amplitudes as low as 60 kPa. As a proof of principle, using the BAACS strategy, we demonstrate the separation of cancer cell line in a suspension with better than 75% efficiency. Moreover, 100% of the microbubble-cell conjugates migrated to the anti-node. Hence a better upstream affinity-capture has the potential to provide higher sorting efficiency. The BAACS technique may potentially provide a simplistic approach for similar sized selective isolation of cells, and is suited for applications in point of care.

  • 49.
    Faridi, Muhammad Asim
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab. mafaridi@kth.se.
    Ramachandraiah, Harisha
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Iranmanesh, Ida Sadat
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Grishenkov, Dmitry
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinsk bildteknik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Russom, Aman
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    MicroBubble Activated Acoustic Cell Sorting: BAACS2017Inngår i: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781, Vol. 19, nr 2, artikkel-id 23Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Acoustophoresis, the ability to acoustically manipulate particles and cells inside a microfluidic channel, is a critical enabling technology for cell-sorting applications. However, one of the major impediments for routine use of acoustophoresis at clinical laboratory has been the reliance on the inherent physical properties of cells for separation. Here, we present a microfluidic-based microBubble-Activated Acoustic Cell Sorting (BAACS) method that rely on the specific binding of target cells to microbubbles conjugated with specific antibodies on their surface for continuous cell separation using ultrasonic standing wave. In acoustophoresis, cells being positive acoustic contrast particles migrate to pressure nodes. On the contrary we show that air-filled polymer-shelled microbubbles being strong negative acoustic contrast particles migrate to pressure antinodes at acoustic pressure amplitudes as low as 60 kPa. As a proof of principle, using the BAACS strategy, we demonstrate the separation of cancer cell line in a suspension with better than 75% efficiency. Moreover, 100% of the microbubble-cell conjugates migrated to the anti-node. Hence a better upstream affinity-capture has the potential to provide higher sorting efficiency. The BAACS technique may potentially provide a simplistic approach for similar sized selective isolation of cells, and is suited for applications in point of care.

  • 50.
    Faridi, Muhammad Asim
    et al.
    KTH.
    Shahzad, Adnan Faqui
    KTH.
    Russom, Aman
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Nanobioteknologi.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Milliliter scale acoustophoresis based bioparticle processing platform2018Inngår i: ASME 2018 16th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM 2018, ASME Press, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Bioparticles such as mammalian cells and bacteria can be manipulated directly or indirectly for multiple applications such as sample preparation for diagnostic applications mainly up-concentration, enrichment & separation as well as immunoassay development. There are various active and passive microfluidic particle manipulation techniques where Acoustophoresis is a powerful technique showing high cell viability. The use of disposable glass capillaries for acoustophoresis, instead of cleanroom fabricated glass-silicon chip can potentially bring down the cost factor substantially, aiding the realization of this technique for real-world diagnostic devices. Unlike available chips and capillary-based microfluidic devices, we report milliliter-scale platform able to accommodate 1ml of a sample for acoustophoresis based processing on a market available glass capillary. Although it is presented as a generic platform but as a demonstration we have shown that polystyrene suspending medium sample can be processed with trapping efficiency of 87% and the up-concentration factor of 10 times in a flow through manner i.e., at 35µl/min. For stationary volume accommodation, this platform practically offers 50 times more sample handling capacity than most of the microfluidic setups. Furthermore, we have also shown that with diluted blood (0.6%) in a flow-through manner, 82% of the white blood cells (WBCs) per ml could be kept trapped. This milliliter platform could potentially be utilized for assisting in sample preparation, plasma separation as well as a flow-through immunoassay assay development for clinical diagnostic applications.

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