A5063512689- Advanced Neuroimaging Techniques and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced X-ray Imaging Techniques
- Advanced MRI Techniques and Applications
- Enzyme Structure and Function
- Advanced Electron Microscopy Techniques and Applications
- Functional Brain Connectivity Studies
- Protein Structure and Dynamics
- Electron and X-Ray Spectroscopy Techniques
- CCD and CMOS Imaging Sensors
- Particle Accelerators and Free-Electron Lasers
- Infrared Target Detection Methodologies
- Advanced NMR Techniques and Applications
- Phase Equilibria and Thermodynamics
- Nuclear Physics and Applications
- Surface and Thin Film Phenomena
- Advanced Chemical Physics Studies
- Quantum Dots Synthesis And Properties
- Laser-Matter Interactions and Applications
- Metal-Catalyzed Oxygenation Mechanisms
- Ion-surface interactions and analysis
- Perovskite Materials and Applications
- High-pressure geophysics and materials
- Analytical Chemistry and Chromatography
- Optical Imaging and Spectroscopy Techniques
SLAC National Accelerator Laboratory
2017-2025
Stanford Synchrotron Radiation Lightsource
2016-2024
University of Applied Health Sciences
2016-2024
Stanford University
2016-2023
University of Nis
2022
Menlo School
2017-2018
Max Planck Institute for Biophysical Chemistry
2010-2016
Paul Scherrer Institute
2014-2016
Max Planck Society
2010-2014
Max Planck Institute for Dynamics and Self-Organization
2011
We present a flexible and compact experimental setup that combines an in vacuum liquid jet with x-ray emission spectrometer to enable static femtosecond time-resolved resonant inelastic soft scattering (RIXS) measurements from liquids at free electron laser (FEL) light sources. demonstrate the feasibility of this type experiments performed Linac Coherent Light Source FEL facility. At we observed changes RIXS spectra high peak fluences which currently sets limit maximum attainable count rate...
Myelin insulates neuronal axons and enables fast signal transmission, constituting a key component of brain development, aging disease. Yet, myelin-specific imaging macroscopic samples remains challenge. Here, we exploit myelin's nanostructural periodicity, use small-angle X-ray scattering tensor tomography (SAXS-TT) to simultaneously quantify myelin levels, integrity axon orientations in nervous tissue. Proof-of-principle is demonstrated whole mouse brain, spinal cord human white gray...
Polymer conformation in solution is more important for R2R solar cell performance than the crystallinity of final coated film.
We utilized femtosecond time-resolved resonant inelastic X-ray scattering and ab initio theory to study the transient electronic structure photoinduced molecular dynamics of a model metal carbonyl photocatalyst Fe(CO)5 in ethanol solution. propose mechanistic explanation for parallel ultrafast intra-molecular spin crossover ligation Fe(CO)4 which are observed following charge transfer photoexcitation as reported our previous [Wernet et al., Nature 520, 78 (2015)]. find that branching...
We use ultrafast electron diffraction to study lattice heating of 20nm noble metal films after femtosecond optical excitation with moderate fluences. Using the Debye–Waller effect, rise times temperature were measured be 1.1ps in copper (5.9mJ∕cm2 incident fluence) and 4.7ps gold (0.9mJ∕cm2).
We present time-resolved femtosecond photoelectron momentum images and angular distributions of dissociating, laser-aligned 1,4-dibromobenzene (C6H4Br2) molecules measured in a near-infrared pump, soft-x-ray probe experiment performed at an x-ray free-electron laser. The observed alignment dependence the bromine 2p is compared to density functional theory calculations interpreted terms diffraction. While no clear time-dependent effects are distribution Br(2p) photoelectrons, other,...
Through an expansive international effort that involved data collection on 12 small-angle X-ray scattering (SAXS) and four neutron (SANS) instruments, 171 SAXS 76 SANS measurements for five proteins (ribonuclease A, lysozyme, xylanase, urate oxidase xylose isomerase) were acquired. From these data, the solvent-subtracted protein profiles shown to be reproducible, with caveat additive constant adjustment was required account small errors in solvent subtraction. Further, major features of...
The two major challenges in synchrotron size-exclusion chromatography coupled in-line with small-angle x-ray scattering (SEC-SAXS) experiments are the overlapping peaks elution profile and fouling of radiation-damaged materials on walls sample cell. In recent years, many post-experimental analyses techniques have been developed applied to extract profiles from these problematic SEC-SAXS data. Here, we present three modes data collection at BioSAXS Beamline 4-2 Stanford Synchrotron Radiation...
In this Letter, we report on the experimental generation of high energy (10 GeV), ultrashort (femtosecond-duration), ultrahigh current (∼0.1 MA), petawatt peak power electron beams in a particle accelerator. These extreme enable exploration new frontier high-intensity beam-light and beam-matter interactions broadly relevant across fields ranging from laboratory astrophysics to strong field quantum electrodynamics ultrafast chemistry. We demonstrate our ability generate control properties...
Surface layers (S-layers) are crystalline protein coats surrounding microbial cells. S-layer proteins (SLPs) regulate their extracellular self-assembly by crystallizing when exposed to an environmental trigger. However, molecular mechanisms governing rapid crystallization in vivo or vitro largely unknown. Here, we demonstrate that the Caulobacter crescentus SLP readily crystallizes into sheets via a calcium-triggered multistep assembly pathway. This pathway involves 2 domains serving...
Supercritical fluids (SCFs) can be found in a variety of environmental and industrial processes. They exhibit an anomalous thermodynamic behavior, which originates from their fluctuating heterogeneous micro-structure. Characterizing the dynamics these at high temperature pressure with nanometer spatial picosecond temporal resolution has been very challenging. The advent hard x-ray free electron lasers enabled development novel multi-pulse ultrafast scattering techniques, such as photon...
The phytochrome family of light-switchable proteins has long been studied by biochemical, spectroscopic and crystallographic means, while a direct probe for global conformational signal propagation lacking. Using solution X-ray scattering, we find that the photosensory cores several bacterial phytochromes undergo similar large-scale structural changes upon red-light excitation. data establish with ordinary inverted photocycles share signaling mechanism particular conserved histidine,...
In an effort to understand recent results showing differences between the power conversion efficiencies of lead halide (CH3NH3PbI3−xClx) solar cells on glass versus flexible substrates, this study investigates influence that substrate and processing methods have morphological crystallographic development. Using our in situ slot-die micro roll-to-roll coater setup, we measured small wide angle X-ray scattering grazing incidence while material dried, enabling us follow crystallization from...
We present a table-top soft-x-ray spectrometer for the wavelength range λ = 1–5 nm based on stable laser-driven x-ray source, making use of gas-puff target. With this setup, optical light-pump/soft-x-ray probe near-edge absorption fine structure (NEXAFS) experiments with temporal resolution about 230 ps are feasible. Pump-probe NEXAFS measurements were carried out in “water-window” region (2.28 nm–4.36 nm) manganite Pr0.7Ca0.3MnO3, investigating diminutive changes oxygen K edge that derive...
In the current work, X-ray emission spectra of aqueous solutions different inorganic salts within Hofmeister series are presented. The results reflect direct interaction ions with water molecules and therefore, reveal general properties salt-water interactions. Within experimental precision a significant effect on structure has been observed but no ordering according to maker/structure breaker concept could be mirrored in indicating that effect-if existent-may caused by more complex
Disentangling human brain connectivity requires an accurate description of nerve fiber trajectories, unveiled via detailed mapping axonal orientations. However, this is challenging because axons can cross one another on a micrometer scale. Diffusion magnetic resonance imaging (dMRI) be used to infer it sensitive alignment, but has limited spatial resolution and specificity. Scattered light (SLI) small-angle X-ray scattering (SAXS) reveal orientations with microscopic high specificity,...
We discuss the observation of a transient (000)-order attenuation in time-resolved transmission electron diffraction experiments. It is shown that this effect causes decrease intensity all higher orders. This not unique to specific materials as it was observed thin Au, Ag and Cu films.
Ultrafast electronic and structural dynamics of matter govern rate selectivity chemical reactions, as well phase transitions efficient switching in functional materials. Since x-rays determine properties with elemental, chemical, orbital magnetic selectivity, short pulse x-ray sources have become central enablers ultrafast science. Despite these strengths, been poor at picking up excited state moieties from the unexcited ones. With time-resolved anti-Stokes resonant Raman scattering...
Abstract X-ray spectroscopy is a powerful tool to study the local charge distribution of chemical systems. Together with liquid jet it becomes possible probe systems in their natural environment, phase. In this work, we present absorption (XA), emission (XE) and resonant inelastic scattering (RIXS) data pure water various salt solutions show possibilities these methods offer elucidate nature ion-water interaction.
Mussels use byssal threads to secure themselves rocks and as shock absorbers during cyclic loading from wave motion. Byssal combine high strength toughness with extensibility of nearly 200%. Researchers attribute tensile properties their elaborate multi-domain collagenous protein cores. Because the elastic have been previously scrutinized, we instead examined thread viscoelastic behaviour, which is essential for withstanding loading. By targeting domains in core via chemical treatments,...
In this paper we present a development of multipurpose vacuum chamber which primal function is to be used in pump/probe experiments with free electron laser (FEL) radiation. The constructed for serial diffraction and spectroscopy allowing fast exchange samples during the measurement process. For samples, liquid jet systems are used. Both applications, utilizing soft x-ray FEL pulses as pump optical probe vice versa documented. Experiments solid well presented. When working jets, system...