scholarly journals Application of electron tomography of dislocations in beam-sensitive quartz to the determination of strain components

2021 ◽  
Vol 803 ◽  
pp. 228754
Author(s):  
Alexandre Mussi ◽  
Julien Gallet ◽  
Olivier Castelnau ◽  
Patrick Cordier
Keyword(s):  
Electron Tomography ◽  
Strain Components

scholarly journals 3D structure determination of native mammalian cells using cryo-FIB and cryo-electron tomography

2012 ◽  
Vol 180 (2) ◽  
pp. 318-326 ◽  
Author(s):  
Ke Wang ◽  
Korrinn Strunk ◽  
Gongpu Zhao ◽  
Jennifer L. Gray ◽  
Peijun Zhang
Keyword(s):  
Structure Determination ◽  
Mammalian Cells ◽  
Electron Tomography ◽  
3D Structure ◽  
Cryo Electron Tomography ◽  
3D Structure Determination

Frontiers in Cryo Electron Microscopy of Complex Macromolecular Assemblies

2019 ◽  
Vol 21 (1) ◽  
pp. 395-415 ◽  
Author(s):  
Jana Ognjenović ◽  
Reinhard Grisshammer ◽  
Sriram Subramaniam
Keyword(s):  
Electron Microscopy ◽  
Cell Biology ◽  
Electron Tomography ◽  
Protein Complexes ◽  
Specimen Preparation ◽  
Macromolecular Assemblies ◽  
Cryo Electron Microscopy ◽  
G Protein Coupled ◽  
Improved Methods

In recent years, cryo electron microscopy (cryo-EM) technology has been transformed with the development of better instrumentation, direct electron detectors, improved methods for specimen preparation, and improved software for data analysis. Analyses using single-particle cryo-EM methods have enabled determination of structures of proteins with sizes smaller than 100 kDa and resolutions of ∼2 Å in some cases. The use of electron tomography combined with subvolume averaging is beginning to allow the visualization of macromolecular complexes in their native environment in unprecedented detail. As a result of these advances, solutions to many intractable challenges in structural and cell biology, such as analysis of highly dynamic soluble and membrane-embedded protein complexes or partially ordered protein aggregates, are now within reach. Recent reports of structural studies of G protein–coupled receptors, spliceosomes, and fibrillar specimens illustrate the progress that has been made using cryo-EM methods, and are the main focus of this review.

CTF Correction in Electron Tomography of Insect Flight Muscle

2001 ◽  
Vol 7 (S2) ◽  
pp. 108-109
Author(s):  
Hanspeter Winkler ◽  
Kenneth A. Taylor
Keyword(s):  
Phase Contrast ◽  
Flight Muscle ◽  
Insect Flight ◽  
Electron Tomography ◽  
Insect Flight Muscle ◽  
Pixel Size ◽  
Contrast Transfer Function ◽  
Typical Specimen ◽  
Complex Wave

In order to extend the resolution available in electron tomograms, we have been experimenting with various deconvolution procedures that will ultimately enable correction of the focus gradient thereby allowing the resolution to be extended to beyond the first zero in the contrast transfer function (CTF). This effort requires first a determination of the amount of amplitude and phase contrast in the typical specimen used by us.For the determination of the percentage of amplitude contrast a focus series of 19 images was taken at a magnification of 13500 on a CM300. The micrographs were digitized on a PDS scanner, the pixel size was 0.888 nm. After correction of translational shifts, rotations, and defocus dependent magnification differences the image restoration was carried out according to [1,2]. From the resulting complex wave function an averaged amplitude contrast amount of 18% was obtained for the stained specimen. The phase contrast part and amplitude contrast part are shown in Figs, 1b, and 1c, respectively, and can be compared with the micrograph taken at 960 nm underfocus (Fig. 1a).

scholarly journals Electron Tomography: Quantitative Structure Determination of Large Three-Dimensional Nanoparticle Assemblies (Part. Part. Syst. Charact. 1/2013)

2012 ◽  
Vol 30 (1) ◽  
pp. 83-83
Author(s):  
Thomas Altantzis ◽  
Bart Goris ◽  
Ana Sánchez-Iglesias ◽  
Marek Grzelczak ◽  
Luis M. Liz-Marzán ◽  
...  
Keyword(s):  
Structure Determination ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Quantitative Structure ◽  
Nanoparticle Assemblies

Comments on the experimental methodology for determination of the hygro-mechanical properties of wood

Holzforschung ◽  
2005 ◽  
Vol 59 (2) ◽  
pp. 232-239 ◽  
Author(s):  
Lech Muszyński ◽  
Rastislav Lagana ◽  
Stephen M. Shaler ◽  
William Davids
Keyword(s):  
Moisture Content ◽  
Local Property ◽  
Basic Mechanism ◽  
Experimental Methodology ◽  
Climate Conditions ◽  
Strain Components ◽  
Tension And Compression ◽  
Basic Parameters ◽  
Loading Modes

Abstract When wood is subjected simultaneously to load and moisture content changes below the fiber saturation point, the mechano-sorptive effect may be observed as an additional deformation that cannot be attributed to simple superposition of elastic deformation, free shrinkage or swelling, or creep in steady climate conditions. The phenomenon has been subject to research for more than half a century. Although numerous mathematical models and detailed theoretical descriptions have been proposed over time, the basic mechanism of mechano-sorption has remained unclear, the experimental data are scattered and lack logical classification, and the experimental determination of its basic parameters on a material level, understood as a local property decoupled from artifacts of the testing protocol, remains a serious challenge. In this paper basic requirements for adequate experimental methods for comprehensive determination of the mechano-sorptive behavior of wood are proposed and briefly discussed. The principal requirements are that the experimental research on mechano-sorption is focused on the material level properties and elementary loading modes (tension and compression); that proper attention is paid to the effect of changing distribution of moisture content within the tested volume; and that the tests are designed so that a comprehensive separation of strain components is enhanced.

scholarly journals Single-atom level determination of 3-dimensional surface atomic structure via neural network-assisted atomic electron tomography

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Juhyeok Lee ◽  
Chaehwa Jeong ◽  
Yongsoo Yang
Keyword(s):  
Functional Properties ◽  
Atomic Structure ◽  
Surface Characterization ◽  
Electron Tomography ◽  
Data Retrieval ◽  
Surface Strain ◽  
Atomic Electron ◽  
Single Atom ◽  
Atom Level

AbstractFunctional properties of nanomaterials strongly depend on their surface atomic structures, but they often become largely different from their bulk structures, exhibiting surface reconstructions and relaxations. However, most of the surface characterization methods are either limited to 2D measurements or not reaching to true 3D atomic-scale resolution, and single-atom level determination of the 3D surface atomic structure for general 3D nanomaterials still remains elusive. Here we demonstrate the measurement of 3D atomic structure at 15 pm precision using a Pt nanoparticle as a model system. Aided by a deep learning-based missing data retrieval combined with atomic electron tomography, the surface atomic structure was reliably measured. We found that <$$100$$ 100 > and <$$111$$ 111 > facets contribute differently to the surface strain, resulting in anisotropic strain distribution as well as compressive support boundary effect. The capability of single-atom level surface characterization will not only deepen our understanding of the functional properties of nanomaterials but also open a new door for fine tailoring of their performance.

scholarly journals Subnanometer-resolution structure determination in situ by a hybrid subtomogram averaging – single particle cryoEM – workflow

2020 ◽  
Author(s):  
Ricardo Sanchez ◽  
Yingyi Zhang ◽  
Wenbo Chen ◽  
Lea Dietrich ◽  
Misha Kudryashev
Keyword(s):  
Single Particle ◽  
Electron Tomography ◽  
Signal To Noise Ratio ◽  
Particle Analysis ◽  
Electron Dose ◽  
Particle Alignment ◽  
Zero Degree ◽  
Subtomogram Averaging

ABSTRACTCryo electron tomography (cryo-ET) combined with subtomogram averaging (StA) enables structural determination of macromolecules in their native context. A few structures were reported by StA at resolution higher than 4.5 Å, however all of these are from viral structural proteins or vesicle coats. Reaching high resolution for a broader range of samples is uncommon due to beam-induced sample drift, poor signal-to-noise ratio (SNR) of images, challenges in CTF correction, limited number of particles. Here we propose a strategy to address these issues, which consists of a tomographic data collection scheme and a processing workflow. Tilt series are collected with higher electron dose at zero-degree tilt in order to increase SNR. Next, after performing StA conventionally, we extract 2D projections of the particles of interest from the higher SNR images and use the single particle analysis tools to refine the particle alignment and generate a reconstruction. We benchmarked our proposed hybrid StA (hStA) workflow and improved the resolution for tobacco mosaic virus from 7.2 to 5.2 Å and the resolution for the ion channel RyR1 in crowded native membranes from 12.9 to 9.1 Å. We demonstrate that hStA can improve the resolution obtained by conventional StA and promises to be a useful tool for StA projects aiming at subnanometer resolution or higher.

scholarly journals In situ structure determination of virus capsids imaged within cell nuclei by correlative light and cryo-electron tomography

2020 ◽  
Author(s):  
Swetha Vijayakrishnan ◽  
Marion McElwee ◽  
Colin Loney ◽  
Frazer Rixon ◽  
David Bhella
Keyword(s):  
Electron Microscopy ◽  
Structure Determination ◽  
Electron Tomography ◽  
3D Structure ◽  
Three Dimensional ◽  
Cell Nuclei ◽  
Nuclear Egress ◽  
Virus Capsids ◽  
Cryo Electron Tomography

AbstractCryo electron microscopy (cryo-EM), a key method for structure determination involves imaging purified material embedded in vitreous ice. Images are then computationally processed to obtain three-dimensional structures at atomic resolution. There is increasing interest in extending structural studies by cryo-EM into the cell, where biological structures and processes may be imaged in context. The limited penetrating power of electrons prevents imaging of thick specimens (>500 nm) however. Cryo-sectioning methods employed to overcome this are technically challenging, subject to artefacts or involve specialised equipment of limited availability. Here we describe the first structure of herpesvirus capsids determined by sub-tomogram averaging from nuclei of eukaryotic cells, achieved by cryo-electron tomography (cryo-ET) of re-vitrified cell sections prepared using the Tokuyasu method. Our reconstructions reveal that the capsid associated tegument complex is present on capsids prior to nuclear egress. We show that this approach to cryogenic imaging of cells is suited to both correlative light/electron microscopy and 3D structure determination.

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