Advances in image simulation for high-resolution TEM

1995 ◽  
Vol 53 ◽  
pp. 38-39
Author(s):  
Michael A. O'Keefe
Keyword(s):  
High Resolution ◽  
Structure Determination ◽  
Incident Beam ◽  
Hrtem Image ◽  
Image Simulation ◽  
Lattice Image ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Projection Approximation

The original high-resolution transmission electron microscope (HRTEM) image simulation program was written as a tool to confirm interpretation of HRTEM images of niobium oxides. Thorough testing on known structures showed that image simulation could reliably duplicate the imaging process occurring in the HRTEM, and could thus be confidently used to interpret images of unknown structures. Mainstream application of image simulation to routine structure determination by HRTEM was ushered in by the establishment of the wide applicability of the SHRLI (simulated high-resolution lattice image) programs. Structure determination of the mineral takéuchiite by HRTEM and image simulation was the first such determination accepted by the KJCr without x-ray data. Of course, once the reliability of image simulation had been established, it was realized that the technique could be put to work for applications other than structure determination. Early on, simulations were used to explore various HRTEM imaging parameters, including specimen ionicity, validity of the projection approximation, and the resolutionlimiting effects of incident-beam convergence. Since the inception of HRTEM image simulation, its range of uses has continued to expand, and so has the number of programs available; distribution of the SHRLI code spawned improved versions as well as some new programs.

scholarly journals Interpretation of HRTEM images by image simulation: An introduction to theory and practice

1994 ◽  
Vol 52 ◽  
pp. 394-395
Author(s):  
Michael A. O’Keefe
Keyword(s):  
High Resolution ◽  
Niobium Oxide ◽  
Incident Beam ◽  
Wide Distribution ◽  
Theory And Practice ◽  
Hrtem Image ◽  
Image Simulation ◽  
Lattice Image ◽  
Image Code ◽  
Imaging Parameters

High-resolution transmission electron microscope (HRTEM) image simulation was conceived in 1970 in response to a referee's questioning of the interpretation of images of a niobium oxide. Two years later a suite of HRTEM image simulation programs had been established and shown to accurately reproduce experimental HRTEM images when imaging parameters were accurately known. These first simulated images proved that the original interpretation of the niobium oxide images was indeed correct. Once these programs were available, it was possible to explore HRTEM imaging parameters including specimen ionicity, validity of the projection approximation, and the resolution-limiting effects of incident-beam convergence. Over the twenty years since then, the range of uses of HRTEM simulation has continued to expand, as has the number of programs available. World-wide distribution of the SHRLI (simulated high-resolution lattice image) code inspired some researchers to produce new or modified simulation programs and others to compare the results produced by these programs (fig.1).

scholarly journals HRTEM image-stitching for measurement of distances

2020 ◽  
Vol 5 (1) ◽  
pp. 13-17
Author(s):  
György Zoltán Radnóczi ◽  
Zoltán Herceg ◽  
Tamás Rafael Kiss
Keyword(s):  
Electron Beam ◽  
High Resolution ◽  
Single Crystal ◽  
Image Stitching ◽  
Hrtem Image ◽  
Lattice Image ◽  
High Resolution Tem ◽  
Better Than

AbstractVery accurate measurement of distances in the order of several µm is demonstrated on a single crystal Si sample by counting the lattice fringes on stitched high resolution TEM/STEM images. Stitching of TEM images commonly relies on correspondence points found in the image, however, the nearly perfect periodic nature of a lattice image renders such a procedure very unreliable. To overcome this difficulty artificial correspondence points are created on the sample using the electron beam. An accuracy better than 1% can be reached while measuring distances in the order of 1 µm. A detailed description of the process is provided, and its usability for accurately measuring large distances is discussed in detail.

scholarly journals High-resolution structure determination of sub-100 kilodalton complexes using conventional cryo-EM

2018 ◽  
Author(s):  
Mark A. Herzik ◽  
Mengyu Wu ◽  
Gabriel C. Lander
Keyword(s):  
High Resolution ◽  
Structure Determination ◽  
Drug Target ◽  
Phase Plate ◽  
Biological Macromolecules ◽  
Cryo Electron Microscopy ◽  
Transmission Electron ◽  
High Resolution Structure ◽  
Resolution Structure

Determining high-resolution structures of biological macromolecules with masses of less than 100 kilodaltons (kDa) has long been a goal of the cryo-electron microscopy (cryo-EM) community. While the Volta Phase Plate has enabled cryo-EM structure determination of biological specimens of this size range, use of this instrumentation is not yet fully automated and can present technical challenges. Here, we show that conventional defocus-based cryo-EM methodologies can be used to determine the high-resolution structures of specimens amassing less than 100 kDa using a transmission electron microscope operating at 200 keV coupled with a direct electron detector. Our ~2.9 Å structure of alcohol dehydrogenase (82 kDa) proves that bound ligands can be resolved with high fidelity, indicating that these methodologies can be used to investigate the molecular details of drug-target interactions. Our ~2.8 Å and ~3.2 Å resolution structures of methemoglobin demonstrate that distinct conformational states can be identified within a dataset for proteins as small as 64 kDa. Furthermore, we provide the first sub-nanometer cryo-EM structure of a protein smaller than 50 kDa.

High Resolution Tem Studies of β-Alumina Type Structures

1983 ◽  
Vol 31 ◽  
Author(s):  
K. J. Morrissey ◽  
Z. Elgat ◽  
Y. Kouh ◽  
C. B. Carter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Analytical Electron Microscopy ◽  
Image Simulation ◽  
Commercial Alumina ◽  
Transmission Electron ◽  
Analytical Electron ◽  
High Resolution Tem ◽  
High Resolution Images

ABSTRACTHigh resolution transmission electron microscopy (HRTEM) has been used to study structures found in secondphase particles in commercial alumina compacts. Analytical electron microscopy has been used to identify elements present in the particles. Computer image simulation has been used for both the structural interpretation of high resolution images and predicting the effect which the presence of other elements would have on the observed structures.

scholarly journals Sub-2 Å Resolution Structure Determination Using Single-Particle Cryo-EM at 200 keV

2019 ◽  
Author(s):  
Mengyu Wu ◽  
Gabriel C. Lander ◽  
Mark A. Herzik
Keyword(s):  
High Resolution ◽  
Structure Determination ◽  
Single Particle ◽  
Structure Based Drug Design ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Ordered Water ◽  
Current Paradigm ◽  
Resolution Single

AbstractAlthough the advent of direct electron detectors (DEDs) and software developments have enabled the routine use of single-particle cryogenic electron microscopy (cryo-EM) for structure determination of well-behaved specimens to high-resolution, there nonetheless remains a discrepancy between the resolutions attained for biological specimens and the information limits of modern transmission electron microscopes (TEMs). Instruments operating at 300 kV equipped with DEDs are the current paradigm for high-resolution single-particle cryo-EM, while 200 kV TEMs remain comparatively underutilized for purposes beyond sample screening. Here, we expand upon our prior work and demonstrate that one such 200 kV microscope, the Talos Arctica, equipped with a K2 DED is capable of determining structures of macromolecules to as high as ∼1.7 Å resolution. At this resolution, ordered water molecules are readily assigned and holes in aromatic residues can be clearly distinguished in the reconstructions. This work emphasizes the utility of 200 keV for high-resolution single-particle cryo-EM and applications such as structure-based drug design.

Quantitative High Resolution Transmission Electron Microscopy - The Role of Space Charge in Blurring Images

1996 ◽  
Vol 466 ◽  
Author(s):  
A. M. Schwartz ◽  
J. M. Gibson ◽  
T. Zheng
Keyword(s):  
High Resolution ◽  
Space Charge ◽  
Image Matching ◽  
Charge Effect ◽  
Hrtem Image ◽  
Quantum Space ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Image Simulations

ABSTRACTWe investigate space-charge by analytic methods and Monte Carlo simulations as a possible source of blur in high-resolution TEM images. In doing so we believe to have identified a novel type of space charge effect, namely quantum space charge(QSC) effect. We predict the blur for typical HRTEM images and for electron holograms. Inclusion of this hitherto unrecognized effect in image simulations (and experimental design for HRTEM and related techniques, such as holography) should permit further progress in the critical field of quantitative HRTEM image matching as a means for atomic structure determination.

High-resolution microscopy of twin boundaries in gold

1987 ◽  
Vol 45 ◽  
pp. 260-261
Author(s):  
William Krakow ◽  
David A. Smith
Keyword(s):  
High Resolution ◽  
Specimen Preparation ◽  
Gold Films ◽  
Boundary Area ◽  
Transmission Electron ◽  
Recent Developments ◽  
Tilt Boundaries ◽  
High Resolution Microscopy ◽  
Twist Boundaries

Recent developments in specimen preparation, imaging and image analysis together permit the experimental determination of the atomic structure of certain, simple grain boundaries in metals such as gold. Single crystal, ∼125Å thick, (110) oriented gold films are vapor deposited onto ∼3000Å of epitaxial silver on (110) oriented cut and polished rock salt substrates. Bicrystal gold films are then made by first removing the silver coated substrate and placing in contact two suitably misoriented pieces of the gold film on a gold grid. Controlled heating in a hot stage first produces twist boundaries which then migrate, so reducing the grain boundary area, to give mixed boundaries and finally tilt boundaries perpendicular to the foil. These specimens are well suited to investigation by high resolution transmission electron microscopy.

On-line alignment and astigmatism correction using a TV and personal computer

1993 ◽  
Vol 51 ◽  
pp. 202-203
Author(s):  
F. Hosokawa ◽  
Y. Kondo ◽  
T. Honda ◽  
Y. Ishida ◽  
M. Kersker
Keyword(s):  
High Resolution ◽  
Personal Computer ◽  
Block Diagram ◽  
Incident Beam ◽  
Ccd Camera ◽  
Alignment Procedure ◽  
Astigmatism Correction ◽  
Transmission Electron ◽  
Alignment System ◽  
On Line

High-resolution transmission electron microscopy must attain utmost accuracy in the alignment of incident beam direction and in astigmatism correction, and that, in the shortest possible time. As a method to eliminate this troublesome work, an automatic alignment system using the Slow-Scan CCD camera has been introduced recently. In this method, diffractograms of amorphous images are calculated and analyzed to detect misalignment and astigmatism automatically. In the present study, we also examined diffractogram analysis using a personal computer and digitized TV images, and found that TV images provided enough quality for the on-line alignment procedure of high-resolution work in TEM. Fig. 1 shows a block diagram of our system. The averaged image is digitized by a TV board and is transported to a computer memory, then a diffractogram is calculated using an FFT board, and the feedback parameters which are determined by diffractogram analysis are sent to the microscope(JEM- 2010) through the RS232C interface. The on-line correction system has the following three modes.

scholarly journals Tricks of the trade used to accelerate high-resolution structure determination of membrane proteins

FEBS Letters ◽  
2010 ◽  
Vol 584 (12) ◽  
pp. 2539-2547 ◽  
Author(s):  
Yo Sonoda ◽  
Alex Cameron ◽  
Simon Newstead ◽  
Hiroshi Omote ◽  
Yoshinori Moriyama ◽  
...  
Keyword(s):  
High Resolution ◽  
Membrane Proteins ◽  
Structure Determination ◽  
High Resolution Structure ◽  
Resolution Structure
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