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  • 1.
    Andreasson, Jakob
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Iwan, Bianca Stella
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Andrejczuk, A.
    Abreu, E.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Bergh, M.
    Caleman, Carl
    Nelson, A. J.
    Bajt, S.
    Chalupsky, J.
    Chapman, H. N.
    Faeustlin, R. R.
    Hajkova, V.
    Heimann, P. A.
    Hjörvarsson, Björgvin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Juha, L.
    Klinger, D.
    Krzywinski, J.
    Nagler, B.
    Pålsson, Gunnar Karl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Singer, W.
    Seibert, Marvin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Sobicrajski, R.
    Tolcikis, S.
    Tschentscher, T.
    Vinko, S. M.
    Lee, R. W.
    Hajdu, Janos
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Timneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Saturated ablation in metal hydrides and acceleration of protons and deuterons to keV energies with a soft-x-ray laser2011In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics, ISSN 1539-3755, E-ISSN 1550-2376, Vol. 83, no 1, p. 016403-Article in journal (Refereed)
    Abstract [en]

    Studies of materials under extreme conditions have relevance to a broad area of research, including planetary physics, fusion research, materials science, and structural biology with x-ray lasers. We study such extreme conditions and experimentally probe the interaction between ultrashort soft x-ray pulses and solid targets (metals and their deuterides) at the FLASH free-electron laser where power densities exceeding 1017 W/cm2 were reached. Time-of-flight ion spectrometry and crater analysis were used to characterize the interaction. The results show the onset of saturation in the ablation process at power densities above 1016 W/cm2. This effect can be linked to a transiently induced x-ray transparency in the solid by the femtosecond x-ray pulse at high power densities. The measured kinetic energies of protons and deuterons ejected from the surface reach several keV and concur with predictions from plasma-expansion models. Simulations of the interactions were performed with a nonlocal thermodynamic equilibrium code with radiation transfer. These calculations return critical depths similar to the observed crater depths and capture the transient surface transparency at higher power densities.

  • 2. Aquila, Andrew
    et al.
    Hunter, Mark S.
    Doak, R. Bruce
    Kirian, Richard A.
    Fromme, Petra
    White, Thomas A.
    Andreasson, Jakob
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Arnlund, David
    Bajt, Saša
    Barends, Thomas R. M.
    Barthelmess, Miriam
    Bogan, Michael J.
    Bostedt, Christoph
    Bottin, Hervé
    Bozek, John D.
    Caleman, Carl
    Coppola, Nicola
    Davidsson, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    DePonte, Daniel P.
    Elser, Veit
    Epp, Sascha W.
    Erk, Benjamin
    Fleckenstein, Holger
    Foucar, Lutz
    Frank, Matthias
    Fromme, Raimund
    Graafsma, Heinz
    Grotjohann, Ingo
    Gumprecht, Lars
    Hajdu, Janos
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Hampton, Christina Y.
    Hartmann, Andreas
    Hartmann, Robert
    Hau-Riege, Stefan
    Hauser, Günter
    Hirsemann, Helmut
    Holl, Peter
    Holton, James M.
    Hömke, André
    Johansson, Linda
    Kimmel, Nils
    Kassemeyer, Stephan
    Krasniqi, Faton
    Kühnel, Kai-Uwe
    Liang, Mengning
    Lomb, Lukas
    Malmerberg, Erik
    Marchesini, Stefano
    Martin, Andrew V.
    Maia, Filipe R.N.C.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Messerschmidt, Marc
    Nass, Karol
    Reich, Christian
    Neutze, Richard
    Rolles, Daniel
    Rudek, Benedikt
    Rudenko, Artem
    Schlichting, Ilme
    Schmidt, Carlo
    Schmidt, Kevin E.
    Schulz, Joachim
    Seibert, M. Marvin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Soltau, Heike
    Shoeman, Robert L.
    Sierra, Raymond
    Starodub, Dmitri
    Stellato, Francesco
    Stern, Stephan
    Strüder, Lothar
    Timneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Ullrich, Joachim
    Wang, Xiaoyu
    Williams, Garth J.
    Weidenspointner, Georg
    Weierstall, Uwe
    Wunderer, Cornelia
    Barty, Anton
    Spence, John C. H.
    Chapman, Henry N.
    Time-resolved protein nanocrystallography using an X-ray free-electron laser2012In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 20, no 3, p. 2706-2716Article in journal (Refereed)
    Abstract [en]

    We demonstrate the use of an X-ray free electron laser synchronized with an optical pump laser to obtain X-ray diffraction snapshots from the photoactivated states of large membrane protein complexes in the form of nanocrystals flowing in a liquid jet. Light-induced changes of Photosystem I-Ferredoxin co-crystals were observed at time delays of 5 to 10 µs after excitation. The result correlates with the microsecond kinetics of electron transfer from Photosystem I to ferredoxin. The undocking process that follows the electron transfer leads to large rearrangements in the crystals that will terminally lead to the disintegration of the crystals. We describe the experimental setup and obtain the first time-resolved femtosecond serial X-ray crystallography results from an irreversible photo-chemical reaction at the Linac Coherent Light Source. This technique opens the door to time-resolved structural studies of reaction dynamics in biological systems.

  • 3. Barty, Anton
    et al.
    Caleman, Carl
    Aquila, Andrew
    Timneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Lomb, Lukas
    White, Thomas A.
    Andreasson, Jakob
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Arnlund, David
    Bajt, Sasa
    Barends, Thomas R. M.
    Barthelmess, Miriam
    Bogan, Michael J.
    Bostedt, Christoph
    Bozek, John D.
    Coffee, Ryan
    Coppola, Nicola
    Davidsson, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    DePonte, Daniel P.
    Doak, R. Bruce
    Ekeberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Elser, Veit
    Epp, Sascha W.
    Erk, Benjamin
    Fleckenstein, Holger
    Foucar, Lutz
    Fromme, Petra
    Graafsma, Heinz
    Gumprecht, Lars
    Hajdu, Janos
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Hampton, Christina Y.
    Hartmann, Robert
    Hartmann, Andreas
    Hauser, Guenter
    Hirsemann, Helmut
    Holl, Peter
    Hunter, Mark S.
    Johansson, Linda
    Kassemeyer, Stephan
    Kimmel, Nils
    Kirian, Richard A.
    Liang, Mengning
    Maia, Filipe R. N. C.
    Malmerberg, Erik
    Marchesini, Stefano
    Martin, Andrew V.
    Nass, Karol
    Neutze, Richard
    Reich, Christian
    Rolles, Daniel
    Rudek, Benedikt
    Rudenko, Artem
    Scott, Howard
    Schlichting, Ilme
    Schulz, Joachim
    Seibert, M. Marvin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Shoeman, Robert L.
    Sierra, Raymond G.
    Soltau, Heike
    Spence, John C. H.
    Stellato, Francesco
    Stern, Stephan
    Strueder, Lothar
    Ullrich, Joachim
    Wang, X.
    Weidenspointner, Georg
    Weierstall, Uwe
    Wunderer, Cornelia B.
    Chapman, Henry N.
    Self-terminating diffraction gates femtosecond X-ray nanocrystallography measurements2012In: Nature Photonics, ISSN 1749-4885, E-ISSN 1749-4893, Vol. 6, no 1, p. 35-40Article in journal (Refereed)
    Abstract [en]

    X-ray free-electron lasers have enabled new approaches to the structural determination of protein crystals that are too small or radiation-sensitive for conventional analysis(1). For sufficiently short pulses, diffraction is collected before significant changes occur to the sample, and it has been predicted that pulses as short as 10 fs may be required to acquire atomic-resolution structural information(1-4). Here, we describe a mechanism unique to ultrafast, ultra-intense X-ray experiments that allows structural information to be collected from crystalline samples using high radiation doses without the requirement for the pulse to terminate before the onset of sample damage. Instead, the diffracted X-rays are gated by a rapid loss of crystalline periodicity, producing apparent pulse lengths significantly shorter than the duration of the incident pulse. The shortest apparent pulse lengths occur at the highest resolution, and our measurements indicate that current X-ray free-electron laser technology(5) should enable structural determination from submicrometre protein crystals with atomic resolution.

  • 4.
    Bergh, Magnus
    et al.
    Swedish Def Res Agcy, S-16490 Stockholm, Sweden..
    Caleman, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics. DESY, Ctr Free Electron Laser Sci, Hamburg, Germany..
    A Validation Study of the General Amber Force Field Applied to Energetic Molecular Crystals2016In: Journal of Energetic Materials, ISSN 0737-0652, E-ISSN 1545-8822, Vol. 34, no 1, p. 62-75Article in journal (Refereed)
    Abstract [en]

    Molecula dynamics is a well-established tool to computationally study molecules. However, to reach predictive capability at the level required for applied research and design, extensive validation of the available force fields is pertinent. Here we present a study of density, isothermal compressibility and coefficients of thermal expansion of four energetic materials (FOX-7, RDX, CL-20 and HMX) based on molecular dynamics simulations with the General Amber Force Field (GAFF), and compare the results to experimental measurements from the literature. Furthermore, we quantify the accuracy of the calculated properties through hydrocode simulation of a typical impact scenario. We find that molecular dynamics simulations with generic and computationally efficient force fields may be used to understand and estimate important physical properties of nitramine-like energetic materials.

  • 5.
    Beyerlein, Kenneth
    et al.
    Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron, Hamburg, Germany.
    Jönsson, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Alonso-Mori, Roberto
    SLAC National Accelerator Laboratory, USA.
    Aquila, Andrew
    SLAC National Accelerator Laboratory, USA.
    Bajt, Sasa
    Photon Science, DESY, Hamburg, Germany.
    Barty, Anton
    Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron, Hamburg, Germany.
    Bean, Richard
    Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron, Hamburg, Germany.
    Koglin, Jason E.
    SLAC National Accelerator Laboratory, USA.
    Messerschmidt, Marc
    SLAC National Accelerator Laboratory, USA.
    Ragazzon, Davide
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Soklaras, Dimosthenis
    SLAC National Accelerator Laboratory, USA.
    Williams, Garth J.
    SLAC National Accelerator Laboratory, USA.
    Hau-Riege, Stefan
    Lawrence Livermore National Laboratory, USA.
    Boutet, Sebastien
    SLAC National Accelerator Laboratory, USA.
    Chapman, Henry N.
    Center for Free-Electron Laser Science,Deutsches Elektronen-Synchrotron, Hamburg, Germany; Department of Physics, University of Hamburg, Hamburg, Germany; Centre for Ultrafast Imaging, University of Hamburg, Hamburg, Germany .
    Timneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Caleman, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics. Center for Free-Electron Laser Science,Deutsches Elektronen-Synchrotron, Hamburg, Germany.
    Ultrafast non-thermal heating of water initiated by an X-ray laser2018In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 115, no 22, p. 5652-5657Article in journal (Refereed)
    Abstract [en]

    X-ray Free-Electron Lasers have opened the door to a new era in structural biology, enabling imaging of biomolecules and dynamics that were impossible to access with conventional methods. A vast majority of imaging experiments, including Serial Femtosecond Crystallography, use a liquid jet to deliver the sample into the interaction region. We have observed structural changes in the carrying water during X-ray exposure, showing how it transforms from the liquid phase to a plasma. This ultrafast phase transition observed in water provides evidence that any biological structure exposed to these X-ray pulses is destroyed during the X-ray exposure.The bright ultrafast pulses of X-ray Free-Electron Lasers allow investigation into the structure of matter under extreme conditions. We have used single pulses to ionize and probe water as it undergoes a phase transition from liquid to plasma. We report changes in the structure of liquid water on a femtosecond time scale when irradiated by single 6.86 keV X-ray pulses of more than 106 J/cm2. These observations are supported by simulations based on molecular dynamics and plasma dynamics of a water system that is rapidly ionized and driven out of equilibrium. This exotic ionic and disordered state with the density of a liquid is suggested to be structurally different from a neutral thermally disordered state.

  • 6. Boutet, Sébastien
    et al.
    Lomb, Lukas
    Williams, Garth J
    Barends, Thomas R M
    Aquila, Andrew
    Doak, R Bruce
    Weierstall, Uwe
    DePonte, Daniel P
    Steinbrener, Jan
    Shoeman, Robert L
    Messerschmidt, Marc
    Barty, Anton
    White, Thomas A
    Kassemeyer, Stephan
    Kirian, Richard A
    Seibert, M Marvin
    Montanez, Paul A
    Kenney, Chris
    Herbst, Ryan
    Hart, Philip
    Pines, Jack
    Haller, Gunther
    Gruner, Sol M
    Philipp, Hugh T
    Tate, Mark W
    Hromalik, Marianne
    Koerner, Lucas J
    van Bakel, Niels
    Morse, John
    Ghonsalves, Wilfred
    Arnlund, David
    Bogan, Michael J
    Caleman, Carl
    Fromme, Raimund
    Hampton, Christina Y
    Hunter, Mark S
    Johansson, Linda C
    Katona, Gergely
    Kupitz, Christopher
    Liang, Mengning
    Martin, Andrew V
    Nass, Karol
    Redecke, Lars
    Stellato, Francesco
    Timneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Wang, Dingjie
    Zatsepin, Nadia A
    Schafer, Donald
    Defever, James
    Neutze, Richard
    Fromme, Petra
    Spence, John C H
    Chapman, Henry N
    Schlichting, Ilme
    High-resolution protein structure determination by serial femtosecond crystallography2012In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 337, no 6092, p. 362-364Article in journal (Refereed)
    Abstract [en]

    Structure determination of proteins and other macromolecules has historically required the growth of high-quality crystals sufficiently large to diffract x-rays efficiently while withstanding radiation damage. We applied serial femtosecond crystallography (SFX) using an x-ray free-electron laser (XFEL) to obtain high-resolution structural information from microcrystals (less than 1 micrometer by 1 micrometer by 3 micrometers) of the well-characterized model protein lysozyme. The agreement with synchrotron data demonstrates the immediate relevance of SFX for analyzing the structure of the large group of difficult-to-crystallize molecules.

  • 7. Caleman, Carl
    et al.
    Bergh, Magnus
    Scott, Howard A.
    Spence, John C. H.
    Chapman, Henry N.
    Timneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Simulations of radiation damage in biomolecular nanocrystals induced by femtosecond X-ray pulses2011In: Journal of Modern Optics, ISSN 0950-0340, E-ISSN 1362-3044, Vol. 58, no 16, p. 1486-1497Article in journal (Refereed)
    Abstract [en]

    The Linac Coherent Light Source (LCLS) is the first X-ray free electron laser to achieve lasing at subnanometer wavelengths (6 angstrom). LCLS is poised to reach even shorter wavelengths (1.5 angstrom) and thus holds the promise of single molecular imaging at atomic resolution. The initial operation at a photon energy of 2 keV provides the possibility to perform the first experiments on damage to biological particles, and to assess the limitations to coherent imaging of biological samples, which are directly relevant at atomic resolution. In this paper we theoretically investigate the damage formation and detection possibilities for a biological crystal, by employing and comparing two different damage models with complementary strengths. Molecular dynamics provides a discrete approach which investigates structural details at the atomic level by tracking all atoms in the real space. Our continuum model is based on a non-local thermodynamics equilibrium code with atomic kinetics and radiation transfer and can treat hydrodynamic expansion of the entire system. The latter approach captures the essential features of atomic displacements, without taking into account structural information and intrinsic atomic movements. This proves to be a powerful computational tool for many samples, including biological crystals, which will be studied with X-ray free electron lasers.

  • 8. Caleman, Carl
    et al.
    Hub, Jochen S.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    van Maaren, Paul J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Atomistic simulation of ion solvation in water explains surface preference of halides2011In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 108, no 17, p. 6838-6842Article in journal (Refereed)
    Abstract [en]

    Water is a demanding partner. It strongly attracts ions, yet some halide anions-chloride, bromide, and iodide-are expelled to the air/water interface. This has important implications for chemistry in the atmosphere, including the ozone cycle. We present a quantitative analysis of the energetics of ion solvation based on molecular simulations of all stable alkali and halide ions in water droplets. The potentials of mean force for Cl-, Br-, and I-have shallow minima near the surface. We demonstrate that these minima derive from more favorable water-water interaction energy when the ions are partially desolvated. Alkali cations are on the inside because of the favorable ion-water energy, whereas F-is driven inside by entropy. Models attempting to explain the surface preference based on one or more ion properties such as polarizability or size are shown to lead to qualitative and quantitative errors, prompting a paradigm shift in chemistry away from such simplifications.

  • 9. Caleman, Carl
    et al.
    Huldt, Gösta
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Maia, Filipe R. N. C.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Ortiz, Carlos
    Parak, Fritz G.
    Hajdu, Janos
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Chapman, Henry N.
    Timneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    On the Feasibility of Nanocrystal Imaging Using Intense and Ultrashort X-ray Pulses2011In: ACS Nano, ISSN 1936-0851, Vol. 5, no 1, p. 139-146Article in journal (Refereed)
    Abstract [en]

    Structural studies of biological macromolecules are severely limited by radiation damage. Traditional crystallography curbs the effects of damage by spreading damage over many copies of the molecule of interest in the crystal. X-ray lasers offer an additional opportunity for limiting damage by out-running damage processes with ultrashort and very intense X-ray pulses Such pulses may allow the imaging of single molecules, clusters; Or nanoparticles: Coherent flash Imaging Will also open up new avenues for structural studies on nano- and microcrystalline substances. This paper addresses the theoretical potentials and limitations of nanocrystallography with extremely intense coherent X-ray pulses. We use urea nanocrystals as a model for generic biological substances and simulate the primary and secondary ionization dynamics in the crystalline sample. The results establish conditions for ultrafast single shot nanocrystallography diffraction experiments as a function of X-ray fluence, pulse duration, and the size of nanocrystals. Nanocrystallography using ultrafast X-ray pulses has the potential to open up a new route in protein crystallography to solve atomic structures of many systems that remain Inaccessible using conventional X-ray sources.

  • 10.
    Caleman, Carl
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Huldt, Gösta
    Ortiz, Carlos
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Materials Theory.
    Maia, Filipe R. N. C.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Marklund, Erik G.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Parak, Fritz G.
    van der Spool, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Timneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Nanocrystal imaging using intense and ultrashort X-ray pulsesManuscript (preprint) (Other (popular science, discussion, etc.))
    Abstract [en]

    Structural studies of biological macromolecules are severely limited by radiation damage. Traditional crystallography curbs the effects of damage by spreading damage over many copies of the molecule of interest in the crystal. X-ray lasers offer an additional opportunity for limiting damage by out-running damage processes with ultrashort and very intense X-ray pulses. Such pulses may allow the imaging of single molecules, clusters or nanoparticles, but coherent flash imaging will also open up new avenues for structural studies on nano- and micro-crystalline substances. This paper addresses the potentials and limitations of nanocrystallography with extremely intense coherent X-ray pulses. We use urea nanocrystals as a model for generic biological substances, and simulate the primary and secondary ionization dynamics in the crystalline sample. The results establish conditions for diffraction experiments as a function of X-ray fluence, pulse duration, and the size of nanocrystals.

  • 11.
    Caleman, Carl
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics. DESY, Ctr Free Electron Laser Sci, Notkestr 85, Hamburg, Germany.
    Jönsson, Olof
    KTH Royal Inst Technol, Dept Appl Phys, S-10691 Stockholm, Sweden.
    Östlin, Christofer
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Timneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics. Uppsala Univ, Dept Phys & Astron, Box 516, Uppsala, Sweden.
    Ultrafast dynamics of water exposed to XFEL pulses2019In: Optics Damage and Materials Processing by EUV/X-ray Radiation VII / [ed] Juha, L Bajt, S Guizard, S, SPIE - International Society for Optical Engineering, 2019, article id 1103507Conference paper (Refereed)
    Abstract [en]

    These proceedings investigate the ionization and temperature dynamics of water samples exposed to intense ultrashort X-ray free-electron laser pulses ranging from 10(4) - 10(7) J/cm(2), based on simulations using a non-local thermodynamic plasma code. In comparison to earlier work combining simulations and experiments, a regime where a hybrid simulations approach should be applicable is presented.

  • 12.
    Caleman, Carl
    et al.
    Physik Department E17, Technische Universität München.
    Ortiz, Carlos
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Materials Theory.
    Marklund, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Bultmark, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Materials Theory.
    Gabrysch, Markus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Parak, F. G.
    Hajdu, Janos
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Klintenberg, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Materials Theory.
    Timneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Radiation damage in biological material: electronic properties and electron impact ionization in urea2009In: Europhysics letters, ISSN 0295-5075, E-ISSN 1286-4854, Vol. 85, no 1, p. 18005-Article in journal (Refereed)
    Abstract [en]

    Radiation damage is an unavoidable process when performing structural investigations of biological macromolecules with X-rays. In crystallography this process can be limited through damage distribution in a crystal, while for single molecular imaging it can be outrun by employing short intense pulses. Secondary electron generation is crucial during damage formation and we present a study of urea, as model for biomaterial. From first principles we calculate the band structure and energy loss function, and subsequently the inelastic electron cross-section in urea. Using Molecular Dynamics simulations, we quantify the damage and study the magnitude and spatial extent of the electron cloud coming from an incident electron, as well as the dependence with initial energy.

  • 13.
    Caleman, Carl
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Timneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Martin, Andrew V.
    Jönsson, H. Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Aquila, Andrew
    Barty, Anton
    Scott, Howard A.
    White, Thomas A.
    Chapman, Henry N.
    Ultrafast self-gating Bragg diffraction of exploding nanocrystals in an X-ray laser2015In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 23, no 2, p. 1213-1231Article in journal (Refereed)
    Abstract [en]

    In structural determination of crystalline proteins using intense femtosecond X-ray lasers, damage processes lead to loss of structural coherence during the exposure. We use a nonthermal description for the damage dynamics to calculate the ultrafast ionization and the subsequent atomic displacement. These effects degrade the Bragg diffraction on femtosecond time scales and gate the ultrafast imaging. This process is intensity and resolution dependent. At high intensities the signal is gated by the ionization affecting low resolution information first. At lower intensities, atomic displacement dominates the loss of coherence affecting high-resolution information. We find that pulse length is not a limiting factor as long as there is a high enough X-ray flux to measure a diffracted signal.

  • 14.
    Caleman, Carl
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Tîmneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Martin, A. V.
    White, T. A.
    Scott, H. A.
    Barty, A.
    Aquila, A.
    Chapman, H. N.
    Modeling of XFEL induced ionization and atomic displacement in protein nanocrystals2012In: Proceedings of SPIE: The International Society for Optical Engineering, 2012, p. 85040H-Conference paper (Refereed)
    Abstract [en]

    X-ray free-electron lasers enable high-resolution imaging of biological materials by using short enough pulses to outrun many of the effects of radiation damage. Experiments conducted at the LCLS have obtained diffraction data from single particles and protein nanocrystals at doses to the sample over 3 GGy. The details of the interaction of the X-ray FEL pulse with the sample determine the limits of this new paradigm for imaging. Recent studies suggest that in the case of crystalline samples, such as protein nanocrystals, the atomic displacements and loss of bound electrons in the crystal (due to the high X- ray intensity) has the effect of gating the diffraction signal, and hence making the experiment less radiation sensitive. Only the incident photon intensity in the first part of the pulse, before the Bragg diffraction has died out, is relevant to acquiring signal and the rest of the pulse will mainly contribute to a diffuse background. In this work we use a plasma based non-local thermodynamic equilibrium code to explore the displacement and the ionization of a protein nanocrystal at various X-ray wavelengths and intensities.

  • 15.
    Caleman, Carl
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Evaporation from water clusters containing singly charged ions2007In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 9, no 37, p. 5105-5111Article in journal (Refereed)
    Abstract [en]

    Molecular dynamics simulations were used to study the evaporation from water clusterscontaining either ClÀ, H2PO4À, Na+ or NH4+ ions. The simulations ranged between 10 and500 ns, and were performed in vacuum starting at 275 K. A number of different models were usedincluding polarizable models. The clusters contain 216 or 512 molecules, 0, 4 or 8 of which wereions. The ions with hydrogen bonding properties do not affect evaporation, even though thephosphate ions have a pronounced ion–ion structure and tend to be inside the cluster whereasammonium shows little ion–ion structure and has a distribution within the cluster similar to thatof the water molecules. Since the individual ion–water interactions are much stronger in the caseof Na+–water and ClÀ–water clusters, evaporation is somewhat slower for clusters containingthese ions. It seems therefore that the main determinant of the evaporation rate in ion–waterclusters is the strength of the interaction. Fission of droplets that contain more ions than allowedaccording to the Rayleigh limit seems to occur more rapidly in clusters containing ammoniumand sodium ions.

  • 16.
    Caleman, Carl
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Picosecond Melting of Ice by an Infrared Laser Pulse2008In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 47, no 8, p. 1417-1420Article in journal (Refereed)
    Abstract [en]

    Cold as ice: Molecular dynamics simulation provides snapshots of a melting ice crystal (see picture). The laser pulse heats up the system, and the energy is absorbed in the OH bonds. After a few picoseconds, the energy is transferred to rotational and translational energy, causing the crystal to melt. The melting starts as a nucleation process, and even long after the first melting is initialized, pockets of crystalline structures can be found.

  • 17.
    Caleman, Carl
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Temperature and structural changes of water clusters in vacuum due to evaporation2006In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 125, no 15, p. 154508-Article in journal (Refereed)
    Abstract [en]

    This paper presents a study on evaporation of pure water clusters. Molecular dynamics simulations between 20 ns and 3 mu s of clusters ranging from 125 to 4096 molecules in vacuum were performed. Three different models (SPC, TIP4P, and TIP5P) were used to simulate water, starting at temperatures of 250, 275, and 300 K. We monitored the temperature, the number of hydrogen bonds, the tetrahedral order, the evaporation, the radial distribution functions, and the diffusion coefficients. The three models behave very similarly as far as temperature and evaporation are concerned. Clusters starting at a higher temperature show a higher initial evaporation rate and therefore reach the point where evaporation stop (around 240 K) sooner. The radius of the clusters is decreased by 0.16-0.22 nm after 0.5 mu s (larger clusters tend to decrease their radius slightly more), which corresponds to around one evaporated molecule per nm(2). The cluster temperature seems to converge towards 215 K independent of cluster size, when starting at 275 K. We observe only small structural changes, but the clusters modeled by TIP5P show a larger percentage of molecules with low diffusion coefficient as t ->infinity, than those using the two other water models. TIP4P seems to be more structured and more hydrogen bonds are formed than in the other models as the temperature falls. The cooling rates are in good agreement with experimental results, and evaporation rates agree well with a phenomenological expression based on experimental observations.

  • 18. Caleman, Carl
    et al.
    van Maaren, Paul J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Hong, Minyan
    Hub, Jochen S.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Costa, Luciano T.
    van der Spoer, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Force Field Benchmark of Organic Liquids: Density, Enthalpy of Vaporization, Heat Capacities, Surface Tension, Isothermal Compressibility, Volumetric Expansion Coefficient, and Dielectric Constant2012In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 8, no 1, p. 61-74Article in journal (Refereed)
    Abstract [en]

    The chemical composition of small organic molecules is often very similar to amino acid side chains or the bases in nucleic acids, and hence there is no a priori reason why a molecular mechanics force field could not describe both organic liquids and biomolecules with a single parameter set. Here, we devise a benchmark for force fields in order to test the ability of existing force fields to reproduce some key properties of organic liquids, namely, the density, enthalpy of vaporization, the surface tension, the heat capacity at constant volume and pressure, the isothermal compressibility, the volumetric expansion coefficient, and the static dielectric constant. Well over 1200 experimental measurements were used for comparison to the simulations of 146 organic liquids. Novel polynomial interpolations of the dielectric constant (32 molecules), heat capacity at constant pressure (three molecules), and the isothermal compressibility (53 molecules) as a function of the temperature have been made, based on experimental data, in order to be able to compare simulation results to them. To compute the heat capacities, we applied the two phase thermodynamics method (Lin et al. J. Chem. Phys. 2003, 119, 11792), which allows one to compute thermodynamic properties on the basis of the density of states as derived from the velocity autocorrelation function. The method is implemented in a new utility within the GROMACS molecular simulation package, named g_dos, and a detailed expose of the underlying equations is presented. The purpose of this work is to establish the state of the art of two popular force fields, OPLS/AA (all-atom optimized potential for liquid simulation) and GAFF (generalized Amber force field), to find common bottlenecks, i.e., particularly difficult molecules, and to serve as a reference point for future force field development. To make for a fair playing field, all molecules were evaluated with the same parameter settings, such as thermostats and barostats, treatment of electrostatic interactions, and system size (1000 molecules). The densities and enthalpy of vaporization from an independent data set based on simulations using the CHARMM General Force Field (CGenFF) presented by Vanommeslaeghe et al. (J. Comput. Chem. 2010, 31, 671) are included for comparison. We find that, overall, the OPLS/AA force field performs somewhat better than GAFF, but there are significant issues with reproduction of the surface tension and dielectric constants for both force fields.

  • 19. Cavalieri, A L
    et al.
    Fritz, D M
    Lee, S H
    Bucksbaum, P H
    Reis, D A
    Rudati, J
    Mills, D M
    Fuoss, P H
    Stephenson, G B
    Kao, C C
    Siddons, D P
    Lowney, D P
    Macphee, A G
    Weinstein, D
    Falcone, R W
    Pahl, R
    Als-Nielsen, J
    Blome, C
    Düsterer, S
    Ischebeck, R
    Schlarb, H
    Schulte-Schrepping, H
    Tschentscher, Th
    Schneider, J
    Hignette, O
    Sette, F
    Sokolowski-Tinten, K
    Chapman, H N
    Lee, R W
    Hansen, T N
    Synnergren, O
    Larsson, J
    Techert, S
    Sheppard, J
    Wark, J S
    Bergh, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    Caleman, C
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    Huldt, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    van der Spoel, D
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    Timneanu, N
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    Hajdu, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    Akre, R A
    Bong, E
    Emma, P
    Krejcik, P
    Arthur, J
    Brennan, S
    Gaffney, K J
    Lindenberg, A M
    Luening, K
    Hastings, J B
    Clocking femtosecond X rays.2005In: Phys Rev Lett, ISSN 0031-9007, Vol. 94, no 11, p. 114801-Article in journal (Refereed)
    Abstract [en]

    Linear-accelerator-based sources will revolutionize ultrafast x-ray science due to their unprecedented brightness and short pulse duration. However, time-resolved studies at the resolution of the x-ray pulse duration are hampered by the inability to precisely synchronize an external laser to the accelerator. At the Sub-Picosecond Pulse Source at the Stanford Linear-Accelerator Center we solved this problem by measuring the arrival time of each high energy electron bunch with electro-optic sampling. This measurement indirectly determined the arrival time of each x-ray pulse relative to an external pump laser pulse with a time resolution of better than 60 fs rms.