scholarly journals An atomic-scale view at the composition of amyloid-beta fibrils by atom probe tomography

2018 ◽  
Author(s):  
Kristiane A.K. Rusitzka ◽  
Leigh T. Stephenson ◽  
Agnieszka Szczepaniak ◽  
Lothar Gremer ◽  
Dierk Raabe ◽  
...  
Keyword(s):  
Amyloid Beta ◽  
Atom Probe Tomography ◽  
Senile Plaques ◽  
Three Dimensional ◽  
Atom Probe ◽  
Pulse Frequency ◽  
Atomic Scale ◽  
Chemical Information ◽  
Protein Fibrils ◽  
Spectrometry Technique

ABSTRACTAmyloid-beta (Aβ) proteins play an important role in a number of neurodegenerative diseases. Aβ is found in senile plaques in brains of Alzeimer’s disease patients. The 42 residues of the monomer form dimers which stack to fibrils gaining several micrometers in length. Using Aβ fibrils with 13C and 15N marker substitution, we developed an innovative approach to obtain insights to structural and chemical information of the protein. We deposited the modified protein fibrils to pre-sharped aluminium needles with >100-nm apex diameters and, using the position-sensitive mass-to-charge spectrometry technique of atom probe tomography, we acquired the chemically-resolved three dimensional information for every detected ion evaporated in small fragments from the protein. We also discuss the influence of experimental parameters such as pulse energy and pulse frequency of the used Laser beam which lead to differences in the size of the gained fragments, developing the capability of localising metal atom within Aβ plaques.

scholarly journals A near atomic-scale view at the composition of amyloid-beta fibrils by atom probe tomography

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Kristiane A. K. Rusitzka ◽  
Leigh T. Stephenson ◽  
Agnieszka Szczepaniak ◽  
Lothar Gremer ◽  
Dierk Raabe ◽  
...  
Keyword(s):  
Amyloid Beta ◽  
Atom Probe Tomography ◽  
Atom Probe ◽  
Atomic Scale

scholarly journals Atom Probe Analysis of Ex Situ Gas-Charged Stable Hydrides

2017 ◽  
Vol 23 (2) ◽  
pp. 307-313 ◽  
Author(s):  
Daniel Haley ◽  
Paul A. J. Bagot ◽  
Michael P. Moody
Keyword(s):  
Atom Probe Tomography ◽  
Three Dimensional ◽  
Atom Probe ◽  
Atomic Scale ◽  
Ex Situ ◽  
Native Oxide ◽  
Probe Analysis ◽  
Atom Probe Tomography Analysis ◽  
Hydrogen Analysis ◽  
Atom Probe Analysis

AbstractIn this work, we report on the atom probe tomography analysis of two metallic hydrides formed by pressurized charging using an ex situ hydrogen charging cell, in the pressure range of 200–500 kPa (2–5 bar). Specifically we report on the deuterium charging of Pd/Rh and V systems. Using this ex situ system, we demonstrate the successful loading and subsequent atom probe analysis of deuterium within a Pd/Rh alloy, and demonstrate that deuterium is likely present within the oxide–metal interface of a native oxide formed on vanadium. Through these experiments, we demonstrate the feasibility of ex situ hydrogen analysis for hydrides via atom probe tomography, and thus a practical route to three-dimensional imaging of hydrogen in hydrides at the atomic scale.

Atomic-Scale Phase Composition through Multivariate Statistical Analysis of Atom Probe Tomography Data

2011 ◽  
Vol 17 (3) ◽  
pp. 418-430 ◽  
Author(s):  
Michael R. Keenan ◽  
Vincent S. Smentkowski ◽  
Robert M. Ulfig ◽  
Edward Oltman ◽  
David J. Larson ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Multivariate Statistical Analysis ◽  
Atom Probe Tomography ◽  
Atom Probe ◽  
Atomic Scale ◽  
Single Atom ◽  
Chemical Information ◽  
Laptop Computer ◽  
Multivariate Statistical ◽  
Tomography Data

AbstractWe demonstrate for the first time that multivariate statistical analysis techniques can be applied to atom probe tomography data to estimate the chemical composition of a sample at the full spatial resolution of the atom probe in three dimensions. Whereas the raw atom probe data provide the specific identity of an atom at a precise location, the multivariate results can be interpreted in terms of the probabilities that an atom representing a particular chemical phase is situated there. When aggregated to the size scale of a single atom (∼0.2 nm), atom probe spectral-image datasets are huge and extremely sparse. In fact, the average spectrum will have somewhat less than one total count per spectrum due to imperfect detection efficiency. These conditions, under which the variance in the data is completely dominated by counting noise, test the limits of multivariate analysis, and an extensive discussion of how to extract the chemical information is presented. Efficient numerical approaches to performing principal component analysis (PCA) on these datasets, which may number hundreds of millions of individual spectra, are put forward, and it is shown that PCA can be computed in a few seconds on a typical laptop computer.

New Frontiers in Electrocatalyst Characterization – Three Dimensional Atomic-Scale Insights By Atom Probe Tomography

2020 ◽  
Vol MA2020-01 (45) ◽  
pp. 2561-2561
Author(s):  
Kevin Schweinar ◽  
Se-Ho Kim ◽  
Joohyun Lim ◽  
Christina Scheu ◽  
Dierk Raabe ◽  
...  
Keyword(s):  
Atom Probe Tomography ◽  
Three Dimensional ◽  
Atom Probe ◽  
Atomic Scale

scholarly journals Three-dimensional atomic mapping of ligands on palladium nanoparticles by atom probe tomography

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kyuseon Jang ◽  
Se-Ho Kim ◽  
Hosun Jun ◽  
Chanwon Jung ◽  
Jiwon Yu ◽  
...  
Keyword(s):  
Atom Probe Tomography ◽  
Electrostatic Interactions ◽  
Density Functional ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Pd Nanoparticles ◽  
Atom Probe ◽  
Atomic Scale ◽  
Colloidal Synthesis ◽  
Spectroscopic Techniques

AbstractCapping ligands are crucial to synthesizing colloidal nanoparticles with functional properties. However, the synergistic effect between different ligands and their distribution on crystallographic surfaces of nanoparticles during colloidal synthesis is still unclear despite powerful spectroscopic techniques, due to a lack of direct imaging techniques. In this study, atom probe tomography is adopted to investigate the three-dimensional atomic-scale distribution of two of the most common types of these ligands, cetrimonium (C19H42N) and halide (Br and Cl) ions, on Pd nanoparticles. The results, validated using density functional theory, demonstrate that the Br anions adsorbed on the nanoparticle surfaces promote the adsorption of the cetrimonium cations through electrostatic interactions, stabilizing the Pd {111} facets. In contrast, the Cl anions are not strongly adsorbed onto the Pd surfaces. The high density of adsorbed cetrimonium cations for Br anion additions results in the formation of multiple-twinned nanoparticles with superior oxidation resistance.

Chemical and Structural Characterization of γ/γ′ Interfaces

2012 ◽  
Vol 463-464 ◽  
pp. 20-24
Author(s):  
Kai Zhao
Keyword(s):  
Atom Probe Tomography ◽  
Three Dimensional ◽  
Atom Probe ◽  
Scanning Transmission Electron Microscope ◽  
Atomic Scale ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Nickel Base

More attention has been paid to the interfaces since mechanical properties of nickel-base superalloys are determined to some degree by them. The compositional transition across γ/γ′ interfaces and atomic structure of the interfaces was investigated using three-dimensional atom probe tomography and scanning transmission electron microscope equipped with high-resolution Energy Dispersive X-ray Spectrometry. Results show that no obvious segregation to the interfaces or ledges of the precipitates in the present experimental alloys has been observed. Also, adsorption of a solute to the interface was not observed. The interfaces are not flat as usually thought at an atomic scale. The interfacial thickness is about two atomic layers, i.e. 0.7 nm.

Prospects for Nanobiology with Atom-Probe Tomography

MRS Bulletin ◽  
2009 ◽  
Vol 34 (10) ◽  
pp. 744-750 ◽  
Author(s):  
Thomas F. Kelly ◽  
Osamu Nishikawa ◽  
J.A. Panitz ◽  
Ty J. Prosa
Keyword(s):  
Atom Probe Tomography ◽  
Three Dimensional ◽  
Chemical Characterization ◽  
Atom Probe ◽  
Inorganic Materials ◽  
Mass Spectrometry Data ◽  
Chemical Information ◽  
Specimen Preparation ◽  
Flight Mass Spectrometry ◽  
Historical Developments

AbstractThe merits of atom-probe tomography (APT) of inorganic materials are well established, as described in this volume. However, one of the long-held aspirations of atom-probe scientists, structural and chemical characterization of organic and biological materials at near-atomic resolution, has yet to be fully realized. A few proof-of-concept type investigations have shown that APT of organic materials is feasible, but a number of challenges still exist with regard to specimen preparation and conversion of raw time-of-flight mass spectrometry data into a three-dimensional map of ions containing structural and chemical information at an acceptable resolution. Recent research aided by hardware improvements and specimen preparation advances has made some progress toward this goal. This article reviews the historical developments in this field, presents some recent results, and considers what life science researchers might expect from this technology.

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