Henry N. Chapman
A5006395860- Advanced X-ray Imaging Techniques
- Advanced Electron Microscopy Techniques and Applications
- Enzyme Structure and Function
- X-ray Spectroscopy and Fluorescence Analysis
- Crystallography and Radiation Phenomena
- Laser-Plasma Interactions and Diagnostics
- Particle Accelerators and Free-Electron Lasers
- Advancements in Photolithography Techniques
- Protein Structure and Dynamics
- Electron and X-Ray Spectroscopy Techniques
- Photosynthetic Processes and Mechanisms
- Computational Drug Discovery Methods
- SARS-CoV-2 and COVID-19 Research
- X-ray Diffraction in Crystallography
- Biochemical and Molecular Research
- Laser-Matter Interactions and Applications
- Advanced X-ray and CT Imaging
- Digital Holography and Microscopy
- Medical Imaging Techniques and Applications
- Crystallization and Solubility Studies
- Photoreceptor and optogenetics research
- Optical measurement and interference techniques
- Mass Spectrometry Techniques and Applications
- Astrophysical Phenomena and Observations
- Adaptive optics and wavefront sensing
Universität Hamburg
2016-2025
Max Planck Institute for the Structure and Dynamics of Matter
2016-2025
Center for Free-Electron Laser Science
2016-2025
Deutsches Elektronen-Synchrotron DESY
2016-2025
Duke University
2023-2025
Hamburg Centre for Ultrafast Imaging
2013-2024
Uppsala University
2007-2024
Hamburg University of Technology
2024
Johannes Gutenberg University Mainz
2024
Helmholtz-Zentrum Berlin für Materialien und Energie
2021
The problem of phase retrieval, i.e., the recovery a function given magnitude its Fourier transform, arises in various fields science and engineering, including electron microscopy, crystallography, astronomy, optical imaging. Exploring retrieval settings, specifically when light originates from laser, is natural since detection devices [e.g., charge-coupled device (CCD) cameras, photosensitive films, human eye] cannot measure wave. This because, generally, measurement that rely on...
Size Matters Less X-ray crystallography is a central research tool for uncovering the structures of proteins and other macromolecules. However, its applicability typically requires growth large crystals, in part because sufficient number molecules must be present lattice sample to withstand x-ray—induced damage. Boutet et al. (p. 362 , published online 31 May) now demonstrate that intense x-ray pulses emitted by free-electron laser source can yield data few enough exposures uncover...
A solution to the inversion problem of scattering would offer aberration-free diffraction-limited three-dimensional images without resolution and depth-of-field limitations lens-based tomographic systems. Powerful algorithms are increasingly being used act as lenses form such images. Current image reconstruction methods, however, require knowledge shape object low spatial frequencies unavoidably lost in experiments. Diffractive imaging has thus previously been increase obtained by other...
It is suggested that, given the magnitude of Fourier transforms sampled at Bragg density, phase problem underdetermined by a factor 2 for 1D, 2D, and 3D objects. therefore unnecessary to oversample 2× in each dimension (i.e., oversampling 4× 2D 8× 3D) retrieving Our computer phasing experiments accurately retrieved from complex-valued objects using positivity constraints on imaginary part loose supports, with much less than 4 8 Under same conditions we also obtained reasonably good...
Coherent x-ray diffraction microscopy is a method of imaging nonperiodic isolated objects at resolutions limited, in principle, by only the wavelength and largest scattering angles recorded. We demonstrate with high resolution all three dimensions, as determined quantitative analysis reconstructed volume images. These images are retrieved from three-dimensional data using no priori knowledge about shape or composition object, which has never before been demonstrated on object. also construct...
In order to address the specific needs of emerging technique `serial femtosecond crystallography', in which structural information is obtained from small crystals illuminated by an X-ray free-electron laser, a new software suite has been created. The constituent programs deal with viewing, indexing, integrating, merging and evaluating quality data, also simulating patterns. challenges addressed chiefly concern indexing integration large numbers diffraction patterns automated manner, so...
Serial femtosecond crystallography using ultrashort pulses from x-ray free electron lasers (XFELs) enables studies of the light-triggered dynamics biomolecules. We used microcrystals photoactive yellow protein (a bacterial blue light photoreceptor) as a model system and obtained high-resolution, time-resolved difference density maps excellent quality with strong features; these allowed determination structures reaction intermediates to resolution 1.6 angstroms. Our results open way study...
X-ray crystallography of G protein-coupled receptors and other membrane proteins is hampered by difficulties associated with growing sufficiently large crystals that withstand radiation damage yield high-resolution data at synchrotron sources. We used an x-ray free-electron laser (XFEL) individual 50-femtosecond-duration pulses to minimize obtained a room-temperature structure human serotonin receptor using sub-10-micrometer microcrystals grown in mimetic matrix known as lipidic cubic phase....
The Trypanosoma brucei cysteine protease cathepsin B (TbCatB), which is involved in host protein degradation, a promising target to develop new treatments against sleeping sickness, fatal disease caused by this protozoan parasite. structure of the mature, active form TbCatB has so far not provided sufficient information for design safe and specific drug T. brucei. By combining two recent innovations, vivo crystallization serial femtosecond crystallography, we obtained room-temperature 2.1...
Visualizing a response to light Many biological processes depend on detecting and responding light. The is often mediated by structural change in protein that begins when absorption of photon causes isomerization chromophore bound the protein. Pande et al. used x-ray pulses emitted free electron laser source conduct time-resolved serial femtosecond crystallography time range 100 fs 3 ms. This allowed for real-time tracking trans-cis photoactive yellow associated changes Science , this issue p. 725
The emerging technique of serial X-ray diffraction, in which diffraction data are collected from samples flowing across a pulsed source at repetition rates 100 Hz or higher, has necessitated the development new software order to handle large volumes produced. Sorting according different criteria and rapid filtering events retain only patterns interest results significant reductions volume, thereby simplifying subsequent analysis management tasks. Meanwhile generation reduced form virtual...
Measuring atomic-resolution images of materials with x-ray photons during chemical reactions or physical transformations resides at the technological forefront science. New x-ray-based experimental capabilities have been closely linked advances in sources, a trend that will continue impending arrival x-ray-free electron lasers driven by accelerators. We discuss recent ultrafast science and coherent imaging made possible linear-accelerator-based light sources. These studies highlight promise...
The motion of atoms on interatomic potential energy surfaces is fundamental to the dynamics liquids and solids. An accelerator-based source femtosecond x-ray pulses allowed us follow directly atomic displacements an optically modified landscape, leading eventually transition from crystalline solid disordered liquid. We show that, first order in time, are inertial, we place constraints shape curvature transition-state surface. Our measurements point toward analogies between this...
The following topics are dealt with: TTF/FLASH in the XFEL context, general layout of facility, accelerator, undulators for SAES and spontaneous emission, photon beamlines scientific instruments, infrastructure auxiliary systems, commissioning operation, project management organization, cost time schedule. (HSI)
We present a proof-of-concept three-dimensional reconstruction of the giant mimivirus particle from experimentally measured diffraction patterns an x-ray free-electron laser. Three-dimensional imaging requires assembly many two-dimensional into internally consistent Fourier volume. Since each is randomly oriented when exposed to pulse, relative orientations have be retrieved data alone. achieve this with modified version expand, maximize and compress algorithm validate our result using new...