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  • 51.
    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.

  • 52.
    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.

  • 53. Fernandez, Angel Rodriguez
    et al.
    Johansson, Ulf
    Carbone, Gerardina
    Bjorling, Alexander
    Kalbfleisch, Sebastian
    Stankevic, Comas
    Bring, Bjorn
    Mikkelsen, Anders
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    NanoMAX Beamline, a nanoprobe beamline for scattering and imaging at MAX IV2018Inngår i: ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES, ISSN 2053-2733, Vol. 74, s. E317-E318Artikkel i tidsskrift (Annet vitenskapelig)
  • 54.
    Fleming, Cassandra L.
    et al.
    Chalmers Univ Technol, Dept Chem & Chem Engn Phys Chem, S-41296 Gothenburg, Sweden.;Univ Gothenburg, Dept Chem & Mol Biol, S-41296 Gothenburg, Sweden..
    Sandoz, Patrick A.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biofysik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Inghardt, Tord
    AstraZeneca, Med Chem, Res & Early Dev Cardiovasc Renal & Metab, BioPharmaceut R&D, Gothenburg, Sweden..
    Önfelt, Björn
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Grotli, Morten
    Univ Gothenburg, Dept Chem & Mol Biol, S-41296 Gothenburg, Sweden..
    Andreasson, Joakim
    Chalmers Univ Technol, Dept Chem & Chem Engn Phys Chem, S-41296 Gothenburg, Sweden..
    A Fluorescent Kinase Inhibitor that Exhibits Diagnostic Changes in Emission upon Binding2019Inngår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The development of a fluorescent LCK inhibitor that exhibits favourable solvatochromic properties upon binding the kinase is described. Fluorescent properties were realised through the inclusion of a prodan-derived fluorophore into the pharmacophore of an ATP-competitive kinase inhibitor. Fluorescence titration experiments demonstrate the solvatochromic properties of the inhibitor, in which dramatic increase in emission intensity and hypsochromic shift in emission maxima are clearly observed upon binding LCK. Microscopy experiments in cellular contexts together with flow cytometry show that the fluorescence intensity of the inhibitor correlates with the LCK concentration. Furthermore, multiphoton microscopy experiments demonstrate both the rapid cellular uptake of the inhibitor and that the two-photon cross section of the inhibitor is amenable for excitation at 700 nm.

  • 55.
    Fogelqvist, Emelie
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Laboratory Soft X-Ray Cryo Microscopy: Source, System and Bio Applications2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Soft x-ray microscopes routinely perform high-resolution 3D imaging of biological cells in their near-native environment with short exposure times at synchrotron radiation facilities. Some laboratory-sized microscopes are aiming to make this imaging technique more accessible to a wider scientific community. However, these systems have been hampered by source instabilities hindering routine imaging of biological samples with short exposure times.

    This Thesis presents work performed on the Stockholm laboratory x-ray microscope. A novel heat control system has been implemented, improving the stability of the laser-produced plasma source. In combination with recent upgrades to the imaging system and an improved cryofixation method, the microscope now has the capability to routinely produce images with 10-second exposure time of cryofixed biological samples. This has allowed for tomographic imaging of cell autophagy and cell-cell interactions. Furthermore, a numerical 3D image formation model is presented as well as a novel reconstruction approach dealing with the limited depth of focus in x-ray microscopes.

  • 56.
    Fogelqvist, Emelie
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Kördel, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Carannante, Valentina
    Önfelt, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellulär biofysik.
    Hertz, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. Karolinska Institutet, Sweden.
    Laboratory cryo x-ray microscopy for 3D cell imaging2017Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, artikkel-id 13433Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Water-window x-ray microscopy allows two-and three-dimensional (2D and 3D) imaging of intact unstained cells in their cryofixed near-native state with unique contrast and high resolution. Present operational biological water-window microscopes are based at synchrotron facilities, which limits their accessibility and integration with complementary methods. Laboratory-source microscopes have had difficulty addressing relevant biological tasks with proper resolution and contrast due to long exposure times and limited up-time. Here we report on laboratory cryo x-ray microscopy with the exposure time, contrast, and reliability to allow for routine high-spatial resolution 3D imaging of intact cells and cell-cell interactions. Stabilization of the laser-plasma source combined with new optics and sample preparation provide high-resolution cell imaging, both in 2D with ten-second exposures and in 3D with twenty-minute tomography. Examples include monitoring of the distribution of carbon-dense vesicles in starving HEK293T cells and imaging the interaction between natural killer cells and target cells.

  • 57.
    Fogelqvist, Emelie
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Kördel, Mikael
    Carannante, Valentina
    Önfelt, Björn
    Hertz, Hans
    Laboratory cryo x-ray microscopy for 3D cell imagingManuskript (preprint) (Annet vitenskapelig)
  • 58.
    Fogelqvist, Emelie
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Kördel, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Selin, Mårten
    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.
    Stability of liquid-nitrogen-jet laser-plasma targets2015Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 118, nr 17, artikkel-id 174902Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Microscopic jets of cryogenic substances such as liquid nitrogen are important regenerative high-density targets for high-repetition rate, high-brightness laser-plasma soft x-ray sources. When operated in vacuum such liquid jets exhibit several non-classical instabilities that negatively influence the x-ray source's spatial and temporal stability, yield, and brightness, parameters that all are important for applications such as water-window microscopy. In the present paper, we investigate liquid-nitrogen jets with a flash-illumination imaging system that allows for a quantitative stability analysis with high spatial and temporal resolution. Direct and indirect consequences of evaporation are identified as the key reasons for the observed instabilities. Operating the jets in an approximately 100 mbar ambient atmosphere counteracts the effects of evaporation and produces highly stable liquid nitrogen jets. For operation in vacuum, which is necessary for the laser plasmas, we improve the stability by introducing an external radiative heating element. The method significantly extends the distance from the nozzle that can be used for liquid-jet laser plasmas, which is of importance for high-average-power applications. Finally, we show that laser-plasma operation with the heating-element-stabilized jet shows improved short-term and long-term temporal stability in its water-window x-ray emission.

  • 59.
    Fogelqvist, Emelie
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Selin, Mårten
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Martz, Dale H.
    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.
    The Stockholm laboratory cryo x-ray microscope: towards cell-cell interaction studies2013Inngår i: 11th International Conference On X-Ray Microscopy (XRM2012), Institute of Physics (IOP), 2013, s. 012054-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We describe recent improvements in the Stockholm laboratory x-ray microscope and the first experiments aiming towards studies of cell-cell interaction. The shorter exposure time due to a higher brightness laser-plasma source will become of large importance for tomography while the reproducible cryo preparation of few-cell samples is essential for the interaction studies.

  • 60. Forslund, E.
    et al.
    Guldevall, Karolin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Olofsson, Per E.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Frisk, Thomas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Christakou, Athanasia E.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Önfelt, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Novel microchip-based tools facilitating live cell imaging and assessment of functional heterogeneity within NK cell populations2012Inngår i: Frontiers in Immunology, ISSN 1664-3224, E-ISSN 1664-3224, Vol. 3, nr OCT, s. 300-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Each individual has a heterogeneous pool of NK cells consisting of cells that may be specialized towards specific functional responses such as secretion of cytokines or killing of tumor cells. Many conventional methods are not fit to characterize heterogeneous populations as they measure the average response of all cells. Thus, there is a need for experimental platforms that provide single cell resolution. In addition, there are transient and stochastic variations in functional responses at the single cell level, calling for methods that allow studies of many events over extended periods of time. This paper presents a versatile microchip platform enabling long-term microscopic studies of individual NK cells interacting with target cells. Each microchip contains an array of microwells, optimized for medium or high-resolution time-lapse imaging of single or multiple NK and target cells, or for screening of thousands of isolated NK-target cell interactions. Individual NK cells confined with target cells in small microwells is a suitable setup for high-content screening and rapid assessment of heterogeneity within populations, while microwells of larger dimensions are appropriate for studies of NK cell migration and sequential interactions with multiple target cells. By combining the chip technology with ultrasonic manipulation, NK and target cells can be forced to interact and positioned with high spatial accuracy within individual microwells.This setup effectively and synchronously creates NK-target conjugates at hundreds of parallel positions in the microchip. Thus, this facilitates assessment of temporal aspects of NK-target cell interactions, e.g., conjugation, immune synapse formation, and cytotoxic events.The microchip platform presented here can be used to effectively address questions related to fundamental functions of NK cells that can lead to better understanding of how the behavior of individual cells add up to give a functional response at the population level.

  • 61.
    Fredenberg, Erik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Medicinsk avbildning.
    Cederström, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ribbing, Carolina
    Danielsson, Mats
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Medicinsk avbildning.
    Prism-array lenses for energy filtering in medical X-ray imaging: Physics of Medical Imaging, Pts 1-32007Inngår i: Medical Imaging 2007: Physics of Medical Imaging, Pts 1-3 / [ed] Hsieh, J; Flynn, MJ, BELLINGHAM: SPIE-INT SOC OPTICAL ENGINEERING , 2007, Vol. 6510, s. U270-U281Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Conventional energy filters for x-ray imaging are based on absorbing materials which attenuate low energy photons, sometimes combined with an absorption edge, thus also discriminating towards 'photons of higher energies. These filters are fairly inefficient, in particular for photons of higher energies, and other methods for achieving a narrower bandwidth have been proposed. Such methods include various types of monochromators, based on for instance mosaic crystals or refractive multi-prism x-ray lenses (MPL's). Prism-array lenses (PAL's) are similar to MPL's, but are shorter, have larger apertures, and higher transmission. A PAL consists of a number of small prisms arranged in columns perpendicular to the optical axis. The column height decreases along the optical axis so that the projection of lens material is approximately linear with a Resnel phase-plate pattern superimposed on it. The focusing effect is one dimensional, and the lens is chromatic. Hence, unwanted energies can be blocked by placing a slit in the image plane of a desired energy. We present the first experimental and theoretical results on an energy filter based on a silicon PAL. The study includes an evaluation of the spectral shaping properties of the filter as well as a quantification of the achievable increase in dose efficiency compared to standard methods. Previously, PAL's have been investigated with synchrotron radiation, but in this study a medical imaging setup, based on a regular x-ray tube, is considered.

  • 62. Freund, Oliver
    et al.
    Bartelt, Michael
    Mittelbach, Marc
    Montgomery, Matthew
    Vogt, Damian M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Seume, Joerg R.
    Impact of the Flow on an Acoustic Excitation System for Aeroelastic Studies2013Inngår i: Journal of turbomachinery, ISSN 0889-504X, E-ISSN 1528-8900, Vol. 135, nr 3, s. 031033-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The flow in turbomachines is highly unsteady. Effects like vortices, flow separation, and shocks are an inevitable part of the turbomachinery flow. Furthermore, high blade aspect ratios, aerodynamically highly loaded and thin profiles increase the blade sensitivity to vibrations. According to the importance of aeroelasticity in turbomachines, new strategies for experimental studies in rotating machines must be developed. A basic requirement for aeroelastic research in rotating machines is to be able to excite the rotor blades in a defined manner. Approaches for active blade excitation in running machines may be piezoelectric elements, magnetism, or acoustics. Contact-free excitation methods are preferred, since additional mistuning is brought into the investigated system otherwise. A very promising method for aeroelastic research is the noncontact acoustic excitation method. In this paper, investigations on the influence of an annular cascade flow on the blade vibration, excited by an acoustic excitation system, are presented for the first time. These investigations are carried out at the Aeroelastic Test Rig of the Royal Institute of Technology in Stockholm. By varying the excitation angle, the outlet Mach number, and the relative position of the excited blade to the excitation system, the influence of the flow on the acoustic excitation is quantified. The results show that there is a strong dependency of the excited vibration amplitude on the excitation angle if the outlet Mach number is increased, which implies that preferable excitation directions exist. Furthermore, it is shown that a benefit up to 23% in terms of excited vibration amplitude can be reached if the flow velocity is raised.

  • 63. Gallo, Paola
    et al.
    Arnann-Winkel, Katrin
    Angell, Charles Austen
    Anisimov, Mikhail Alexeevich
    Caupin, Frederic
    Chakravarty, Charusita
    Lascaris, Erik
    Loerting, Thomas
    Panagiotopoulos, Athanassios Zois
    Russo, John
    Sellberg, Jonas Alexander
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Stanley, Harry Eugene
    Tanaka, Hajime
    Vega, Carlos
    Xu, Limei
    Pettersson, Lars Gunnar Moody
    Water: A Tale of Two Liquids2016Inngår i: Chemical Reviews, ISSN 0009-2665, E-ISSN 1520-6890, Vol. 116, nr 13, s. 7463-7500Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Water is the most abundant liquid on earth and also the substance with the largest number of anomalies in its properties. It is a prerequisite for life and as such a most important subject of current research in chemical physics and physical chemistry. In spite of its simplicity as a liquid, it has an enormously rich phase diagram where different types of ices, amorphous phases, and anomalies disclose a path that points to unique thermodynamics of its supercooled liquid state that still hides many unraveled secrets. In this review we describe the behavior of water in the regime from ambient conditions to the deeply supercooled region. The review describes simulations and experiments on this anomalous liquid. Several scenarios have been proposed to explain the anomalous properties that become strongly enhanced in the supercooled region. Among those, the second critical-point scenario has been investigated extensively, and at present most experimental evidence point to this scenario. Starting from very low temperatures, a coexistence line between a high-density amorphous phase and a low-density amorphous phase would continue in a coexistence line between a high-density and a low-density liquid phase terminating in a liquid liquid critical point, LLCP. On approaching this LLCP from the one-phase region, a crossover in thermodynamics and dynamics can be found. This is discussed based on a picture of a temperature-dependent balance between a high-density liquid and a low-density liquid favored by, respectively, entropy and enthalpy, leading to a consistent picture of the thermodynamics of bulk water. Ice nucleation is also discussed, since this is what severely impedes experimental investigation of the vicinity of the proposed LLCP. Experimental investigation of stretched water, i.e., water at negative pressure, gives access to a different regime of the complex water diagram. Different ways to inhibit crystallization through confinement and aqueous solutions are discussed through results from experiments and simulations using the most sophisticated and advanced techniques. These findings represent tiles of a global picture that still needs to be completed. Some of the possible experimental lines of research that are essential to complete this picture are explored.

  • 64.
    Ghorbani, Morteza
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Medicinsk avbildning. Sabanci Univ, Fac Engn & Nat Sci, Mechatron Engn Program, TR-34956 Istanbul, Turkey.
    Olofsson, Karl
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Benjamins, Jan-Willem
    Research Institute of Sweden (RISE), Chemistry, Materials and Surfaces, Box 5607, SE-114 86 Stockholm, Sweden.
    Loskutova, Ksenia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Medicinsk avbildning.
    Paulraj, Thomas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Grishenkov, Dmitry
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Medicinsk avbildning.
    Svagan, Anna Justina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Unravelling the Acoustic and Thermal Responses of Perfluorocarbon Liquid Droplets Stabilized with Cellulose Nanofibers2019Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 35, nr 40, s. 13090-13099Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The attractive colloidal and physicochemical properties of cellulose nanofibers (CNFs) at interfaces have recently been exploited in the facile production of a number of environmentally benign materials, e.g. foams, emulsions, and capsules. Herein, these unique properties are exploited in a new type of CNF-stabilized perfluoropentane droplets produced via a straightforward and simple mixing protocol. Droplets with a comparatively narrow size distribution (ca. 1–5 μm in diameter) were fabricated, and their potential in the acoustic droplet vaporization process was evaluated. For this, the particle-stabilized droplets were assessed in three independent experimental examinations, namely temperature, acoustic, and ultrasonic standing wave tests. During the acoustic droplet vaporization (ADV) process, droplets were converted to gas-filled microbubbles, offering enhanced visualization by ultrasound. The acoustic pressure threshold of about 0.62 MPa was identified for the cellulose-stabilized droplets. A phase transition temperature of about 22 °C was observed, at which a significant fraction of larger droplets (above ca. 3 μm in diameter) were converted into bubbles, whereas a large part of the population of smaller droplets were stable up to higher temperatures (temperatures up to 45 °C tested). Moreover, under ultrasound standing wave conditions, droplets were relocated to antinodes demonstrating the behavior associated with the negative contrast particles. The combined results make the CNF-stabilized droplets interesting in cell-droplet interaction experiments and ultrasound imaging.

  • 65.
    Girnyk, Maksym A.
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Kommunikationsteori.
    Vehkapera, Mikko
    Rasmussen, Lars Kildehoj
    Christakou, Athanasia
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Onfelt, Bjorn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Orange, Jordan
    Lytic granule convergence is essential for NK cells to promote targeted killing while preventing collateral damage2016Inngår i: Journal of Immunology, ISSN 0022-1767, E-ISSN 1550-6606, Vol. 196Artikkel i tidsskrift (Annet vitenskapelig)
  • 66. Gleber, S. -C
    et al.
    Sedlmair, J.
    Bertilson, Michael
    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.
    Heim, S.
    Guttmann, P.
    Hertz, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Fischer, P.
    Thieme, J.
    X-ray stereo microscopy for investigation of dynamics in soils2009Inngår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 186, s. 012104-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The here presented combination of stereo imaging and elemental mapping with soft X-ray microscopy reveals the spatial arrangement of naturally aqueous colloidal systems, e.g. iron oxides in soil colloid clusters. Changes in the spatial arrangement can be induced by manipulating the sample in-situ and thus be investigated directly and as a function of time.

  • 67.
    Gorkhover, Tais
    et al.
    Tech Univ Berlin, Inst Opt & Atomare Phys, Berlin, Germany.;SLAC Natl Accelerator Lab, Linac Coherent Light Source, Stanford, CA 94025 USA.;SLAC Natl Lab, Stanford PULSE Inst, Menlo Pk, CA 94025 USA..
    Ulmer, Anatoli
    Tech Univ Berlin, Inst Opt & Atomare Phys, Berlin, Germany..
    Ferguson, Ken
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Stanford, CA 94025 USA.;SLAC Natl Lab, Stanford PULSE Inst, Menlo Pk, CA 94025 USA..
    Bucher, Max
    Tech Univ Berlin, Inst Opt & Atomare Phys, Berlin, Germany.;SLAC Natl Accelerator Lab, Linac Coherent Light Source, Stanford, CA 94025 USA.;Argonne Natl Lab, Chem Sci & Engn Div, Lemont, IL USA..
    Maia, Filipe R. N. C.
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden.;Lawrence Berkeley Natl Lab, NERSC, Berkeley, CA USA..
    Bielecki, Johan
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden.;European XFEL GmbH, Schenefeld, Germany..
    Ekeberg, Tomas
    DESY, Ctr Free Electron Laser Sci, Hamburg, Germany..
    Hantke, Max F.
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden..
    Daurer, Benedikt J.
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden..
    Nettelblad, Carl
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden.;Uppsala Univ, Div Sci Comp, Dept Informat Technol, Sci Life Lab, Uppsala, Sweden..
    Andreasson, Jakob
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden.;Czech Acad Sci, Inst Phys, ELI Beamlines, Prague, Czech Republic.;Chalmers Univ Technol, Dept Phys, Condensed Matter Phys, Gothenburg, Sweden..
    Barty, Anton
    DESY, Ctr Free Electron Laser Sci, Hamburg, Germany..
    Bruza, Petr
    Czech Acad Sci, Inst Phys, ELI Beamlines, Prague, Czech Republic..
    Carron, Sebastian
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Stanford, CA 94025 USA..
    Hasse, Dirk
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden..
    Krzywinski, Jacek
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Stanford, CA 94025 USA..
    Larsson, Daniel S. D.
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden..
    Morgan, Andrew
    DESY, Ctr Free Electron Laser Sci, Hamburg, Germany..
    Muhlig, Kerstin
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden..
    Mueller, Maria
    Tech Univ Berlin, Inst Opt & Atomare Phys, Berlin, Germany..
    Okamoto, Kenta
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden..
    Pietrini, Alberto
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden..
    Rupp, Daniela
    Tech Univ Berlin, Inst Opt & Atomare Phys, Berlin, Germany..
    Sauppe, Mario
    Tech Univ Berlin, Inst Opt & Atomare Phys, Berlin, Germany..
    van der Schot, Gijs
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden..
    Seibert, Marvin
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, 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, Uppsala, Sweden..
    Svenda, Martin
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden..
    Swiggers, Michelle
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Stanford, CA 94025 USA..
    Timneanu, Nicusor
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden.;Uppsala Univ, Dept Phys & Astron, Uppsala, Sweden..
    Westphal, Daniel
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden..
    Williams, Garth
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Stanford, CA 94025 USA.;Brookhaven Natl Lab, NSLS 2, Upton, NY 11973 USA..
    Zani, Alessandro
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden..
    Chapman, Henry N.
    DESY, Ctr Free Electron Laser Sci, Hamburg, Germany..
    Faigel, Gyula
    Inst Solid State Phys & Opt, Wigner RCP, Budapest, Hungary..
    Moeller, Thomas
    Tech Univ Berlin, Inst Opt & Atomare Phys, Berlin, Germany..
    Hajdu, Janos
    Uppsala Univ, Dept Cell & Mol Biol, Lab Mol Biophys, Uppsala, Sweden.;European XFEL GmbH, Schenefeld, Germany.;Czech Acad Sci, Inst Phys, ELI Beamlines, Prague, Czech Republic..
    Bostedt, Christoph
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Stanford, CA 94025 USA.;SLAC Natl Lab, Stanford PULSE Inst, Menlo Pk, CA 94025 USA.;Argonne Natl Lab, Chem Sci & Engn Div, Lemont, IL USA.;Northwestern Univ, Dept Phys, Evanston, IL 60208 USA..
    Femtosecond X-ray Fourier holography imaging of free-flying nanoparticles2018Inngår i: Nature Photonics, ISSN 1749-4885, E-ISSN 1749-4893, Vol. 12, nr 3, s. 150-+Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ultrafast X-ray imaging on individual fragile specimens such as aerosols(1), metastable particles(2), superfluid quantum systems(3) and live biospecimens(4) provides high-resolution information that is inaccessible with conventional imaging techniques. Coherent X-ray diffractive imaging, however, suffers from intrinsic loss of phase, and therefore structure recovery is often complicated and not always uniquely defined(4,5). Here, we introduce the method of in-flight holography, where we use nanoclusters as reference X-ray scatterers to encode relative phase information into diffraction patterns of a virus. The resulting hologram contains an unambiguous three-dimensional map of a virus and two nanoclusters with the highest lateral resolution so far achieved via single shot X-ray holography. Our approach unlocks the benefits of holography for ultrafast X-ray imaging of nanoscale, non-periodic systems and paves the way to direct observation of complex electron dynamics down to the attosecond timescale.

  • 68.
    Guldevall, Karolin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Frisk, Thomas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Vanherberghen, Bruno
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Khorsidi, Mohammed Ali
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Manneberg, Otto
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Christakou, Athanasia
    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.
    Imaging immune surveillance by individual Natural Killer cells isolated in arrays of nanoliter wells2010Konferansepaper (Fagfellevurdert)
  • 69.
    Guldevall, Karolin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Vanherberghen, Bruno
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Frisk, Thomas
    Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet.
    Hurtig, Johan
    Department of Chemsitry, University of Washington, Seattle, USA.
    Christakou, Athanasia
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Manneberg, Otto
    Department of Environmental Health, Harvard School of Public Health, Boston, USA.
    Lindström, Sara
    KTH, Skolan för bioteknologi (BIO), Nanobioteknologi (stängd 20130101).
    Andersson-Svahn, Helene
    KTH, Skolan för bioteknologi (BIO), Nanobioteknologi (stängd 20130101).
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Önfelt, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Imaging Immune Surveillance of Individual Natural Killer Cells Confined in Microwell Arrays2010Inngår i: PLOS ONE, ISSN 1932-6203, Vol. 5, nr 11, s. e15453-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    New markers are constantly emerging that identify smaller and smaller subpopulations of immune cells. However, there is a growing awareness that even within very small populations, there is a marked functional heterogeneity and that measurements at the population level only gives an average estimate of the behaviour of that pool of cells. New techniques to analyze single immune cells over time are needed to overcome this limitation. For that purpose, we have designed and evaluated microwell array systems made from two materials, polydimethylsiloxane (PDMS) and silicon, for high-resolution imaging of individual natural killer (NK) cell responses. Both materials were suitable for short-term studies (<4 hours) but only silicon wells allowed long-term studies (several days). Time-lapse imaging of NK cell cytotoxicity in these microwell arrays revealed that roughly 30% of the target cells died much more rapidly than the rest upon NK cell encounter. This unexpected heterogeneity may reflect either separate mechanisms of killing or different killing efficiency by individual NK cells. Furthermore, we show that high-resolution imaging of inhibitory synapse formation, defined by clustering of MHC class I at the interface between NK and target cells, is possible in these microwells. We conclude that live cell imaging of NK-target cell interactions in multi-well microstructures are possible. The technique enables novel types of assays and allow data collection at a level of resolution not previously obtained. Furthermore, due to the large number of wells that can be simultaneously imaged, new statistical information is obtained that will lead to a better understanding of the function and regulation of the immune system at the single cell level.

  • 70. Gustafsson, J.
    et al.
    Terenius, E.
    Buchheister, J.
    Unsbo, Peter
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Peripheral astigmatism in emmetropic eyes2001Inngår i: Ophthalmic & physiological optics, ISSN 0275-5408, E-ISSN 1475-1313, Vol. 21, nr 5, s. 393-400Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The long-term aim of the work introduced here is to investigate the influence of off-axis aberrations on human vision, especially for subjects with a large central scotoma. The latter use their peripheral vision in spite of its poor off-axis optical quality, and a correction of the off-axis aberrations might be of great assistance. The eccentric fixation angles used by these subjects can be up to 20-30 degrees. In this initial study we have measured oblique astigmatism, the major off-axis aberration, in 20 emmetropic eyes in 10 degrees steps out to 60 degrees nasally and temporally using a 'double pass' setup. The results show very large individual differences and the oblique astigmatism also varies from nasal to temporal side. In an off-axis measurement angle of 30 degrees the astigmatism varied between subjects from 1 to 7-D, with a mean astigmatism of about 4-D on the nasal side and about 1.5-D lower on the temporal side. At 60 degrees temporally, the mean astigmatism was 7-D. At 60 degrees nasally, all subjects had astigmatism larger than 8-D and the mean astigmatism was 11-D. The results indicate that any attempt to correct the off axis astigmatism in an eye with central scotoma cannot be based on central refraction; instead, individual measurements are necessary.

  • 71. Gustafsson, J.
    et al.
    Unsbo, Peter
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Eccentric correction for off-axis vision in central visual field loss2003Inngår i: Optometry and Vision Science, ISSN 1040-5488, E-ISSN 1538-9235, Vol. 80, nr 7, s. 535-541Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background. Subjects with absolute central visual field loss use. eccentric fixation and magnifying devices to utilize their residual vision. This preliminary study investigated the importance of an accurate eccentric correction of off-axis refractive errors to optimize the residual visual function for these subjects. Methods. Photorefraction using the PowerRefractor instrument was used to evaluate the ametropia in eccentric fixation angles. Methods were adapted for measuring visual acuity outside the macula using filtered optotypes from high-pass resolution perimetry. Optical corrections were implemented, and the visual function of subjects with central visual field loss was measured with and without eccentric correction. Results. Of the seven cases reported, five experienced an improvement in visual function in their preferred retinal locus with eccentric refraction. Conclusions. The main result was that optical correction for better image quality on the peripheral retina is important for the vision of subjects with central visual field loss, objectively as well as subjectively.

  • 72. Hansson, B. A. M.
    et al.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Liquid-xenon-jet LPP source2006Inngår i: EUV Sources for Lithography, SPIE - International Society for Optical Engineering, 2006, s. 619-647Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 73.
    Hertz, Hans
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hemberg, Oscar
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Metod och apparat för alstring av röntgenstrålning: Method And Apparatus For Generating X-Ray Radiation2000Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    In a method and an apparatus for generating X-ray or EUV radiation, an electron beam is brought to interact with a propagating target jet, typically in a vacuum chamber. The target jet is formed by urging a liquid substance under pressure through an outlet opening. Hard X-ray radiation may be generated by converting the electron-beam energy to Bremsstrahlung and characteristic line emission, essentially without heating the jet to a plasma-forming temperature. Soft X-ray or EUV radiation may be generated by the electron beam heating the jet to a plasma-forming temperature.

  • 74.
    Hertz, Hans M.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Bertilson, Michael C.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Chubarova, Elena
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hemberg, Oscar
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hofsten, Olov Von
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lindblom, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lundström, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Nilsson, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Otendal, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Reinspach, Julia
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Skoglund, Peter
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Takman, Per
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Tuohimaa, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Laboratory X-ray micro- and nano-imaging2009Inngår i: Frontiers in Optics (FiO) 2009, Optical Society of America, 2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We summarize recent progress in laboratory x-ray imaging systems based on compact high-brightness liquid-jet sources, including <25 nm soft x-ray zone-plate microscopy and <10 μm (lens-free) hard x-ray phase-contrast imaging.

  • 75.
    Hertz, Hans M.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Bertilson, Michael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Chubarova, Elena
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Ewald, Johannes
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Gleber, S-C
    Hemberg, Oscar
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Henriksson, M.
    von Hofsten, Olov
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lindblom, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Mudry, Emeric
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Otendal, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Reinspach, Julia
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Schlie, Moritz Gustav
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Skoglund, Peter
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Takman, Per
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Thieme, J.
    Sedlmair, J.
    Tjörnhammar, Richard
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Tuohimaa, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vita, M.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Laboratory x-ray micro imaging: Sources, optics, systems and applications2009Inngår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 186Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We summarize the recent progress in laboratory-scale soft and hard x-ray micro imaging in Stockholm. Our soft x-ray work is based on liquid-jet laser-plasma sources which are combined with diffractive and multilayer optics to form laboratory x-ray microscopes. In the hard x-ray regime the imaging is based on a liquid-metal-jet electron-impact source which provides the necessary coherence to allow phase-contrast imaging with high fidelity.

  • 76.
    Hertz, Hans M.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Bertilson, Michael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    von Hofsten, Olof
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Gleber, S.-C.
    Sedlmair, J.
    Thieme, J.
    Laboratory X-ray microscopy for high-resolution imaging of environmental colloid structure2012Inngår i: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 329, nr SI, s. 26-31Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Transmission X-ray microscopy is a uniquely suited technique for studies of environmental colloids since it allows imaging in aqueous media with high spatial resolution, presently down to the 20 nm range. Such nanoscale morphological description of these high-specific-surface-area compounds show promise for improved understanding of soils, sediments or groundwater aquifers. However, present high-quality X-ray microscopes are located at synchrotron radiation facilities resulting in limited applicability and accessibility for colloid scientists. Here we investigate the applicability of a laboratory-scale transmission X-ray microscope for studies of colloids of the environment. The microscope is based on a laser-plasma source in combination with multilayer and zone plate optics. Samples are held at atmospheric pressure in their natural wet state. We show images revealing the nano-scale morphology of the clay nontronite, soils such as chernozem and luvisol, and the mineral hematite, an iron oxide. Comparative studies of dried substances clearly show the need for imaging in the wet state. The image quality approaches that of synchrotron-based microscopes, albeit at longer exposure times. Stereo imaging is investigated as a means for giving 3D information with shorter exposure times than tomography requires. Finally the future development of the laboratory X-ray microscope is discussed, especially with regard to the reduction of exposure times.

  • 77.
    Hertz, Hans M.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hemberg, O.
    Otendal, M.
    Tuohimaa, T.
    Hansson, B. A. M.
    Electron-Impact Liquid-Metal-Jet Hard x-Ray Sources2014Inngår i: Comprehensive Biomedical Physics, Elsevier, 2014, Vol. 8, s. 91-109Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    The power and brightness of electron-impact microfocus x-ray sources have long been limited by thermal damage in the target. This is a major constraint for a wide range of biomedical applications, from imaging to diffraction. Here, we describe the development of an x-ray microfocus source based on a new target concept, the liquid-metal jet (LMJ). The regenerative nature of this target allows for significantly higher e-beam power density than on conventional targets, resulting in this source showing promise for >. 100. × higher brightness than state-of-the-art sources. We first discuss the basic physics of the two important subsystems of the source, LMJ in vacuum and focused electron-beam systems, and then describe the properties of several versions of the source, from early prototypes to the first LMJ sources now reaching the market. Finally, we review some early applications of the source for biomedical imaging and diffraction.

  • 78.
    Hertz, Hans M.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Larsson, Jakob C.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lundström, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Larsson, Daniel H.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Carmen
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Laboratory x-ray fluorescence tomography for high-resolution nanoparticle bio-imaging2014Inngår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 39, nr 9, s. 2790-2793Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate that nanoparticle x-ray fluorescence computed tomography in mouse-sized objects can be performed with very high spatial resolution at acceptable dose and exposure times with a compact laboratory system. The method relies on the combination of the 24 keV line-emission from a high-brightness liquid-metal-jet x-ray source, pencil-beam-forming x-ray optics, photon-counting energy-dispersive detection, and carefully matched (Mo) nanoparticles. Phantom experiments and simulations show that the arrangement significantly reduces Compton background and allows 100 mu m detail imaging at dose and exposure times compatible with small-animal experiments. The method provides a possible path to in vivo molecular x-ray imaging at sub-100 mu m resolution in mice.

  • 79.
    Hertz, Hans
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Otendal, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Tuohimaa, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Metod för alstring av röntgenstrålning genom elektronbestrålning av en flytande substans2006Patent (Annet (populærvitenskap, debatt, mm))
  • 80.
    Hertz, Hans
    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.
    Bertilson, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    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.
    Reinspach, Julia Antonia
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Martz, Dale
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Selin, Mårten
    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
    Laboratory cryo soft X-ray microscopy2012Inngår i: Journal of Structural Biology, ISSN 1047-8477, E-ISSN 1095-8657, Vol. 177, nr 2, s. 267-272Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lens-based water-window X-ray microscopy allows two- and three-dimensional (2D and 3D) imaging of intact unstained cells in their near-native state with unprecedented contrast and resolution. Cryofixation is essential to avoid radiation damage to the sample. Present cryo X-ray microscopes rely on synchrotron radiation sources, thereby limiting the accessibility for a wider community of biologists. In the present paper we demonstrate water-window cryo X-ray microscopy with a laboratory-source-based arrangement. The microscope relies on a lambda = 2.48-nm liquid-jet high-brightness laser-plasma source, normal-incidence multilayer condenser optics, 30-nm zone-plate optics, and a cryo sample chamber. We demonstrate 2D imaging of test patterns, and intact unstained yeast, protozoan parasites and mammalian cells. Overview 3D information is obtained by stereo imaging while complete 3D microscopy is provided by full tomographic reconstruction. The laboratory microscope image quality approaches that of the synchrotron microscopes, but with longer exposure times. The experimental image quality is analyzed from a numerical wave-propagation model of the imaging system and a path to reach synchrotron-like exposure times in laboratory microscopy is outlined.

  • 81.
    Holmberg, Anders
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lindblom, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Reinspach, Julia
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Bertilson, Michael
    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.
    Soft x-ray zone plate fabrication at KTH, Stockholm2009Inngår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 186Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present the status of our zone plate and test object fabrication processes along with the latest fabricated components. With our nickel process, zone plates with outermost zone width of 20 nm and zone height of 90 nm have been fabricated. A gold electroplating process has recently been introduced for the fabrication of test objects. The first result for gold gratings with 70 nm period and 135 nm height is shown.

  • 82.
    Holmberg, Anders
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Reinspach, Julia
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lindblom, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Chubarova, Elena
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Bertilson, Michael
    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.
    Nilsson, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Selin, Mårten
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Larsson, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Skoglund Lindberg, Peter
    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
    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.
    Towards 10-nm Soft X-Ray Zone Plate Fabrication2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper the latest efforts to improve our nanofabrication process for soft x‐ray zone plates is presented. The resolving power, which is proportional to the smallest outermost zone width of the zone plate, is increased by introducing cold development of the electron beam resist that is used for the patterning. With this process we have fabricated Ni zone plates with 13‐nm outermost zone and shown potential for making 11‐nm half‐pitch lines in the electron beam resist. Maintaining the diffraction efficiency of the zone plate is a great concern when the outermost zone width is decreased. To resolve this problem we have developed the so‐called Ni‐Ge zone plate in which the zone plate is build up by Ni and Ge, resulting in an increase of the diffraction efficiency. In a proof‐of‐principle experiment with 25‐nm Ni‐Ge zone plates, we have shown a doubling of the diffraction efficiency. When combined with cold development, the Ni‐Ge process has been shown to work down to 16‐nm half‐pitch. It is plausible that further refinement of the process will make it possible to go to 10‐nm outermost zone widths.

  • 83. Hoppe, R.
    et al.
    Meier, V.
    Patommel, J.
    Seiboth, F.
    Lee, H. J.
    Nagler, B.
    Galtier, E. C.
    Arnold, B.
    Zastrau, U.
    Hastings, J.
    Nilsson, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Uhlén, Fredrik
    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 M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Schroer, C. G.
    Schropp, A.
    Full characterization of a focused wavefield with sub 100 nm resolution2013Inngår i: Advances In X-Ray Free-Electron Lasers II: Instrumentation, SPIE - International Society for Optical Engineering, 2013, s. 87780G-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A hard x-ray free-electron laser (XFEL) provides an x-ray source with an extraordinary high peak-brilliance, a time structure with extremely short pulses and with a large degree of coherence, opening the door to new scientific fields. Many XFEL experiments require the x-ray beam to be focused to nanometer dimensions or, at least, benefit from such a focused beam. A detailed knowledge about the illuminating beam helps to interpret the measurements or is even inevitable to make full use of the focused beam. In this paper we report on focusing an XFEL beam to a transverse size of 125nm and how we applied ptychographic imaging to measure the complex wavefield in the focal plane in terms of phase and amplitude. Propagating the wavefield back and forth we are able to reconstruct the full caustic of the beam, revealing aberrations of the nano-focusing optic. By this method we not only obtain the averaged illumination but also the wavefield of individual XFEL pulses.

  • 84. Hsu, Hsiang-Ting
    et al.
    Mace, Emily M.
    Carisey, Alexandre F.
    Viswanath, Dixita I.
    Christakou, Athanasia
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Önfelt, Bjorn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Orange, Jordan S.
    NK cells converge lytic granules to promote cytotoxicity and prevent bystander killing2016Inngår i: Journal of Cell Biology, ISSN 0021-9525, E-ISSN 1540-8140, Vol. 215, nr 6, s. 875-889Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Natural killer (NK) cell activation triggers sequential cellular events leading to destruction of diseased cells. We previously identified lytic granule convergence, a dynein-and integrin signal-dependent movement of lysosome-related organelles to the microtubule-organizing center, as an early step in the cell biological process underlying NK cell cytotoxicity. Why lytic granules converge during NK cell cytotoxicity, however, remains unclear. We experimentally controlled the availability of human ligands to regulate NK cell signaling and promote granule convergence with either directed or nondirected degranulation. By the use of acoustic trap microscopy, we generated specific effector-target cell arrangements to define the impact of the two modes of degranulation. NK cells with converged granules had greater targeted and less nonspecific "bystander" killing. Additionally, NK cells in which dynein was inhibited or integrin blocked under physiological conditions demonstrated increased nondirected degranulation and bystander killing. Thus, NK cells converge lytic granules and thereby improve the efficiency of targeted killing and prevent collateral damage to neighboring healthy cells.

  • 85.
    Hultström, Jessica
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Manneberg, Otto
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Dopf, Katja
    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.
    Brismar, Hjalmar
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Proliferation and viability of adherent cells manipulated by standing-wave ultrasound in a microfluidic chip2007Inngår i: Ultrasound in Medicine and Biology, ISSN 0301-5629, E-ISSN 1879-291X, Vol. 33, s. 145-151Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ultrasonic-standing-wave (USW) technology has potential to become a standard method for gentle and contactless cell handling in microfluidic chips. We investigate the viability of adherent cells exposed to USWs by studying the proliferation rate of recultured cells following ultrasonic trapping and aggregation of low cell numbers in a microfluidic chip. The cells form 2-D aggregates inside the chip and the aggregates are held against a continuous flow of cell culture medium perpendicular to the propagation direction of the standing wave. No deviations in the doubling time from expected values (24 to 48 h) were observed for COS-7 cells held in the trap at acoustic pressure amplitudes up to 0.85 MPa and for times ranging between 30 and 75 min. Thus, the results demonstrate the potential of ultrasonic standing waves as a tool for gentle manipulation of low cell numbers in microfluidic systems.

  • 86.
    Hultström, Jessica
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Manneberg, Otto
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Brismar, Hjalmar
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Proliferation and viability of COS-7 cells trapped by standing-wave ultrasound in a microfluidic chip2006Inngår i: Micro Total Analysis Systems - Proceedings of MicroTAS 2006 Conference, Japan Academic Association Inc , 2006, s. 449-451Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We study cell viability after ultrasonic-standing-wave trapping of low cell numbers in a microfluidic chip by recultivation of the trapped cells. The cell proliferation rate is estimated by counting of initial and final cell numbers and shows normal cell growth. The results demonstrate the potential of ultrasonic standing waves as a tool for gentle and long-term manipulation of low cell numbers in microfluidic systems.

  • 87.
    Hultström, Jessica
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Manneberg, Otto
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Towards gentle long-term cell manipulation in a microfluidic chip using ultrasonic standing wave technology2007Inngår i: Proc. 1st International Congress on Ultrasonics, 2007Konferansepaper (Fagfellevurdert)
  • 88.
    Hultström, Jessica
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Manneberg, Otto
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Dopf, Katja
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Brismar, Hjalmar
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Viability of ultrasonically trapped cells2005Inngår i: Proc. 9th Annual European Conference on Micro & Nanoscale Technologies for the Biosciences, 2005Konferansepaper (Fagfellevurdert)
  • 89.
    Häggmark, Ilian
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Romell, Jenny
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lewin, Susanne
    Öhman, Caroline
    Hertz, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik. KTH, Skolan för teknikvetenskap (SCI), Fysik. KTH, Skolan för bioteknologi (BIO), Centra, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Cellular-Resolution Imaging of Microstructures in Rat Bone using Laboratory Propagation-Based Phase-Contrast X-ray Tomography2018Inngår i: Microscopy and Microanalysis, 2018, Vol. 24, s. 368-369Konferansepaper (Fagfellevurdert)
  • 90.
    Häggmark, Ilian
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vågberg, William
    Hertz, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Burvall, Anna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Comparison of quantitative multi-material phase-retrieval algorithms in propagation-based phase-contrast X-ray tomography2017Inngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 25, nr 26, s. 33543-33558Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Propagation-based phase-contrast X-ray imaging provides high-resolution, dose-efficient images of biological materials. A crucial challenge is quantitative reconstruction, referred to as phase retrieval, of multi-material samples from single-distance, and hence incomplete, data. In this work, the two most promising methods for multi-material samples, the parallel method, and the linear method, are analytically, numerically, and experimentally compared. Both methods are designed for computed tomography, as they rely on segmentation in the tomographic reconstruction. The methods are found to result in comparable image quality, but the linear method provides faster reconstruction. In addition, as already done for the parallel method, we show that the linear method provides quantitative reconstruction for monochromatic radiation.

  • 91.
    Häggmark, Ilian
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vågberg, William
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Burvall, Anna
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Biomedical Applications of Multi-Material Phase Retrieval in Propagation-Based Phase-Contrast Imaging2018Inngår i: Microscopy and Microanalysis, Cambridge University Press, 2018, Vol. 24, s. 370-371Konferansepaper (Fagfellevurdert)
  • 92.
    Iranmanesh, Ida
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Barnkob, R.
    Bruus, H.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Magnitude and variance of acoustic energy density in microchannel acoustophoresis: Comparison between single-frequency and frequency-modulated actuation2013Inngår i: 17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013, 2013, Vol. 3, s. 1400-1402Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Using a novel light-intensity method, we quantify for the first time the magnitude and spatial variance in acoustic energy density along a microchannel during acoustophoretic focusing of particles with frequency-modulated ultrasound. We compare the distribution in energy density between single-frequency (SF) and frequency-modulation (FM) actuation along the microchannel. In addition, we analyze the field uniformity for the two actuation approaches (SF and FM) by measuring the deviation of the final particle pattern from an ideal straight line. We conclude that the magnitude of the energy density for FM actuation is of the same order of magnitude as for SF actuation, but with much less spatial variance.

  • 93.
    Iranmanesh, Ida
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Ohlin, Mathias
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Ramachandraiah, Harisha
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Ye, Simon
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Russom, Aman
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Acoustic micro-vortexing of fluids, particles and cells in disposable microfluidic chips2016Inngår i: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781, Vol. 18, nr 4, artikkel-id 71Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate an acoustic platform for microvortexing in disposable polymer microfluidic chips with small-volume (20 mu l) reaction chambers. The described method is demonstrated for a variety of standard vortexing functions, including mixing of fluids, re-suspension of a pellet of magnetic beads collected by a magnet placed on the chip, and lysis of cells for DNA extraction. The device is based on a modified Langevin-type ultrasonic transducer with an exponential horn for efficient coupling into the microfluidic chip, which is actuated by a low-cost fixed-frequency electronic driver board. The transducer is optimized by numerical modelling, and different demonstrated vortexing functions are realized by actuating the transducer for varying times; from fractions of a second for fluid mixing, to half a minute for cell lysis and DNA extraction. The platform can be operated during 1 min below physiological temperatures with the help of a PC fan, a Peltier element and an aluminum heat sink acting as the chip holder. As a proof of principle for sample preparation applications, we demonstrate on-chip cell lysis and DNA extraction within 25 s. The method is of interest for automating and chip-integrating sample preparation procedures in various biological assays.

  • 94.
    Iranmanesh, Ida Sadat
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    On-chip Ultrasonic Sample Preparation2015Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Acoustofluidics has become a well-established technology in the lab-on-a-chip scientific community. The technology involves primarily the manipulation of fluids and/or particles in microfluidic systems. It is used today for variety of applications such as handling, sorting, washing and separation of cells or micro-particles, and for mixing and pumping of fluids. When such manipulation functions are integrated in micro-devices, the technology has been used for clinical sample preparation as well as for studying various fundamental bio-related questions.

    In this doctoral thesis, we have developed different acoustic methods and micro-devices with the aim to create a multi-functional sample preparation platform. We introduced a simple method for in-situ measurements of acoustic energy densities inside a microfluidic channel, from which acoustic pressure amplitudes can be extracted. The method has been used for determining the magnitude of acoustic radiation forces acting on suspended particles and cells inside an acoustofluidic system. For optimization of acoustophoresis (i.e. manipulation of particles into the nodes of standing waves), we have investigated different designs of ultrasonic transducers based on tunable-angle wedges and backing layers attached to glass-silicon microfluidic chips. Furthermore, we have investigated the implementation of frequency-modulated actuation methodology combined with broadbanded ultrasonic transducers, and the implementation of multiple ultrasonic manipulation functions localized to spatially separated zones in a complex microchannel network. We demonstrate two different bio-applications useful for multi-step and multi-functional sample preparation. First, we demonstrate a micro-device for size-based separation, isolation and up-concentration of cells, followed by microscopy-based dynamic monitoring of individual cell properties when introducing different reagents. This holds great promise for use in cellular and molecular diagnostics. Second, we demonstrate an acoustic method for micro-vortexing in µL-volume reaction chambers in disposable polymer chips. The method is used for fast mixing of fluids, for disaggregating and re-suspending magnetically trapped and clumped micro-beads, and for cell lysis followed by DNA extraction. Finally, we demonstrate a temperature-controlled device compatible with high-acoustic-pressure (1 MPa) ultrasonic manipulation of cells, and we demonstrate that cells can be exposed to standing-wave ultrasound at 1 MPa for one hour without compromising the cell viability.

  • 95.
    Iranmanesh, Ida Sadat
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Barnkob, R.
    Bruus, H.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Tunable-angle wedge transducer for improved acoustophoretic control in a microfluidic chip2013Inngår i: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 23, nr 10, s. 105002-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a tunable-angle wedge ultrasound transducer for improved control of microparticle acoustophoresis in a microfluidic chip. The transducer is investigated by analyzing the pattern of aligned particles and induced acoustic energy density while varying the transducer geometry, transducer coupling angle, and transducer actuation method (single-frequency actuation or frequency-modulation actuation). The energy-density analysis is based on measuring the transmitted light intensity through a microfluidic channel filled with a suspension of 5 mu m diameter beads and the results with the tunable-angle transducer are compared with the results from actuation by a standard planar transducer in order to decouple the influence from change in coupling angle and change in transducer geometry. We find in this work that the transducer coupling angle is the more important parameter compared to the concomitant change in geometry and that the coupling angle may be used as an additional tuning parameter for improved acoustophoretic control with single-frequency actuation. Further, we find that frequency-modulation actuation is suitable for diminishing such tuning effects and that it is a robust method to produce uniform particle patterns with average acoustic energy densities comparable to those obtained using single-frequency actuation.

  • 96.
    Iranmanesh, Ida Sadat
    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.
    Ramachandraiah, Harisha
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Russom, Aman
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Acoustic micro-vortexing of fluids, beads and cells in disposable microfluidic chipsManuskript (preprint) (Annet vitenskapelig)
  • 97. Jaeken, Bart
    et al.
    Lundström, Linda
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Artal, Pablo
    Fast scanning peripheral wave-front sensor for the human eye2011Inngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 19, nr 8, s. 7903-7913Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We designed and built a fast scanning peripheral Hartmann-Shack (HS) wave-front sensor to measure the off-axis wave-front aberrations in the human eye. The new instrument is capable of measuring the optical quality over the central 80 degrees horizontal visual field in 1.8 seconds with an angular resolution of 1 degrees. The subject has an open field of view without any moving elements in the line-of-sight and the head is kept in place by a head-chin rest. The same efficiency, reliability and measurement quality as the current static HS sensor were found but with much higher acquisition speed and comfort for the patients. This instrument has the potential to facilitate and improve future research on the peripheral optical quality of the eye in large groups of subjects.

  • 98. Jaeken, Bart
    et al.
    Lundström, Linda
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Artal, Pablo
    Peripheral aberrations in the human eye for different wavelengths: off-axis chromatic aberration2011Inngår i: Optical Society of America. Journal A: Optics, Image Science, and Vision, ISSN 1084-7529, E-ISSN 1520-8532, Vol. 28, nr 9, s. 1871-1879Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The interest in the eye's off-axis aberrations has increased strongly. On-axis the conversion of the aberration magnitude between different wavelengths is well known. We verified if this compensation is correct also for off-axis measurements by building a wavelength tunable peripheral Hartmann-Shack sensor and measuring 11 subjects out to +/- 30 degrees in the horizontal visual field. At the fovea, an average longitudinal chromatic aberration of 1D between red (671 nm) and blue (473 nm) light was found, and it increased slightly with eccentricity (up to 1.2D). A similar trend was measured for astigmatism as a function of wavelength (increase similar to 0.15D). Computational ray tracing in model eyes showed that the origin of the small increase of chromatic aberrations with eccentricity is the change of the oblique power of the refractive surfaces in the eye. Factors related to increase of axial length and refractive index of the eye were found to have a very small influence.

  • 99.
    Jansson, Per
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ultich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Liquid-nitrogen-jet laser-plasma source for compact soft x-ray microscopy2005Inngår i: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 76, nr 4, s. 043503-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We describe a liquid-nitrogen-jet laser-plasma source with sufficient brightness, uniformity, stability, and reliability to be suitable for compact water-window soft x-ray transmission microscopy. A cooled capillary nozzle arrangement allows long-term operation and avoids previously reported jet instabilities. The source is quantitatively characterized by calibrated slit-grating spectroscopy and zone-plate imaging. The absolute photon number in the major spectral lines (lambda=2.48 nm and lambda=2.88 nm) is 1.0x10(12) photons/(pulsexsrxline). The source diameter is similar to 20 mu m (full width at half maximum) and the spatial stability is better than +/- 2 mu m. Within an area with uniformity of 20%, the average source brightness is 4x10(8) photons/(pulsexsrx mu m(2)xline), which allows operation of a compact soft x-ray transmission microscope with exposure times of a few minutes.

  • 100. Johannsen, Gunnar
    et al.
    Tellefsen, Georg
    Johannsen, Annsofi
    Liljeborg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    The importance of measuring toothpaste abrasivity in both a quantitative and qualitative way2013Inngår i: Acta Odontologica Scandinavica, ISSN 0001-6357, E-ISSN 1502-3850, Vol. 71, nr 3-4, s. 508-517Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objective. To evaluate the relative abrasivity of different toothpastes and polishing pastes both qualitatively and quantitatively. Materials and methods. Acrylic plates were exposed to brushing in a brushing machine with a toothpaste/water slurry for 1 and 6 h. Twelve different toothpastes were used and also four different polishing pastes. The results were evaluated using a profilometer after 1 and 6 h of brushing (corresponding to 2000 and 12 000 double strokes, respectively). A surface roughness value (Ra-value) and also a volume loss value were calculated from the profilometer measurements. These values were then correlated to each other. An unpaired t-test for the difference in the abrasion values between the toothpastes and the abrasion values over time was used. Results. The polishing paste RDA (R) 170 yielded higher Ra-values than RDA 250 (R), both after 1 and 6 h of brushing (1.01 +/- 0.22 and 8.99 +/- 1.55 compared to 0.63 +/- 0.26 and 7.83 +/- 5.89, respectively) as well as volume loss values (3.71 +/- 0.17 and 20.20 +/- 2.41 compared to 2.15 +/- 1.41 and 14.79 +/- 11.76, respectively), thus poor correlations between the RDA and Ra and Volume loss values were shown. Among the toothpastes, Apotekets (R) showed the highest Ra value after 1 h of brushing and Pepsodent (R) whitening after 6 h of brushing. Pepsodent (R) whitening also showed the highest volume loss values, both after 1 and 6 h of brushing. Conclusion. This study emphasizes the importance of not only considering the RDA value, but also a roughness value, when describing the abrasivity of a toothpaste. Furthermore, it can be concluded that so called 'whitening' toothpastes do not necessarily have a higher abrasive effect than other toothpastes.

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