FemtoMAX – an X-ray beamline for structural dynamics at the short-pulse facility of MAX IV
- 1 MAX IV Laboratory, Lund University, P. O. Box 118, Lund, 22100, Sweden.
- 2 Department of Physics, Lund University, PO Box 118, Lund 22100, Sweden
- 3 Dectris AG, Taefernweg, Baden-Daettwil 15405, Switzerland
- 4 Departments of Physics and Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, USA
- 5 Department of Environmental Science, Aarhus University, Roskilde 4000, Denmark
- 6 Center for Quantum Electronics, Institute of Physics, Vietnam Academy of Science and Technology, Hanoi, Vietnam
- 7 Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
The FemtoMAX beamline facilitates studies of the structural dynamics of materials. Such studies are of fundamental importance for key scientific problems related to programming materials using light, enabling new storage media and new manufacturing techniques, obtaining sustainable energy by mimicking photosynthesis, and gleaning insights into chemical and biological functional dynamics. The FemtoMAX beamline utilizes the MAX IV linear accelerator as an electron source. The photon bursts have a pulse length of 100 fs, which is on the timescale of molecular vibrations, and have wavelengths matching interatomic distances (Å). The uniqueness of the beamline has called for special beamline components. This paper presents the beamline design including ultrasensitive X-ray beam-position monitors based on thin Ce:YAG screens, efficient harmonic separators and novel timing tools.
Solvent-free and biocompatible multiphased organic-inorganic hybrid nanocomposites.
Biocompatible chemically cross-linked organic-inorganic (O-I) hybrid nanocomposites were developed using a new atoxic, simple and fast, solvent-free pathway. Poly(ε-caprolactone) (PCL) and poly(ethylene glycol) (PEG), which are both biocompatible, were used as the organic moieties (at different PCL/PEG ratios), while in situ synthesized polysilsesquioxanes made up the inorganic moiety. The O-I hybrid nanocomposites’ molecular structures were characterized using solid-state 29Si NMR, TGA and ATR-IR. Results showed an unusually high condensation yield of approximately 90% and two distinct silsesquioxane structures. No traces of the remaining isocyanate groups were found. Advanced morphological characterization of the ternary O-I hybrids was performed using a combination of electron microscopy and X-ray scattering techniques such as SEM, TEM, ESI-TEM, WAXS and temperature-dependent SAXS. Results showed the occurrence of spherical nanoparticles, associated with polysilsesquioxane, and ordered network grains, associated with PCL and/or PEG chains cross-linked by silsesquioxane cages. As a consequence, a four-phased nanostructured morphology was proposed. In this model, PCL and PEG are undistinguishable, while polysilsesquioxane nanoparticles are uniformly distributed throughout a homogeneous cross-linked matrix, which shows gel-like behavior. Moreover, a mobile phase made up of unbound polymer chains occurs at the grain interface.
Rapid Acquisition of X-Ray Scattering Data from Droplet-Encapsulated Protein Systems.
- 1 Institute for X-ray Physics, Georg-August-University Göttingen, 37077, Göttingen, Germany.
- 2 Current address: European XFEL GmbH, 22869, Schenefeld, Germany.
- 3 Paul Scherrer Institute, 5232, Villigen, Switzerland.
- 4 Current address: MAX IV Laboratory, Lund University, 221-00, Lund, Sweden.
- 5 Institute of Inorganic Chemistry, Graz University of Technology, 8010, Graz, Austria.
- 6 European Synchrotron Radiation Facility, 38000, Grenoble, France.
- 7 Department of Analytical Chemistry, Ghent University, 9000, Ghent, Belgium.
Encapsulating reacting biological or chemical samples in microfluidic droplets has the great advantage over single-phase flows of providing separate reaction compartments. These compartments can be filled in a combinatoric way and prevent the sample from adsorbing to the channel walls. In recent years, small-angle X-ray scattering (SAXS) in combination with microfluidics has evolved as a nanoscale method of such systems. Here, we approach two major challenges associated with combining droplet microfluidics and SAXS. First, we present a simple, versatile, and reliable device, which is both suitable for stable droplet formation and compatible with in situ X-ray measurements. Second, we solve the problem of “diluting” the sample signal by the signal from the oil separating the emulsion droplets by multiple fast acquisitions per droplet and data thresholding. We show that using our method, even the weakly scattering protein vimentin provides high signal-to-noise ratio data.
cytoskeletal intermediate filaments; microfluidics; small-angle X-ray scattering; vimentin; water-in-oil emulsions