New Frontiers in Cryo-electron Tomography with Zernike Phase Contrast Imaging for Transmission Electron Microscopy

2008 ◽  
Vol 14 (S2) ◽  
pp. 1072-1073
Author(s):  
B Armbruster ◽  
J Brink ◽  
H Furukawa ◽  
TC Isabell ◽  
M Kawasaki ◽  
...  

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Annie Horng ◽  
Johannes Stroebel ◽  
Tobias Geith ◽  
Stefan Milz ◽  
Alexandra Pacureanu ◽  
...  

Abstract Background The evolution of cartilage degeneration is still not fully understood, partly due to its thinness, low radio-opacity and therefore lack of adequately resolving imaging techniques. X-ray phase-contrast imaging (X-PCI) offers increased sensitivity with respect to standard radiography and CT allowing an enhanced visibility of adjoining, low density structures with an almost histological image resolution. This study examined the feasibility of X-PCI for high-resolution (sub-) micrometer analysis of different stages in tissue degeneration of human cartilage samples and compare it to histology and transmission electron microscopy. Methods Ten 10%-formalin preserved healthy and moderately degenerated osteochondral samples, post-mortem extracted from human knee joints, were examined using four different X-PCI tomographic set-ups using synchrotron radiation the European Synchrotron Radiation Facility (France) and the Swiss Light Source (Switzerland). Volumetric datasets were acquired with voxel sizes between 0.7 × 0.7 × 0.7 and 0.1 × 0.1 × 0.1 µm3. Data were reconstructed by a filtered back-projection algorithm, post-processed by ImageJ, the WEKA machine learning pixel classification tool and VGStudio max. For correlation, osteochondral samples were processed for histology and transmission electron microscopy. Results X-PCI provides a three-dimensional visualization of healthy and moderately degenerated cartilage samples down to a (sub-)cellular level with good correlation to histologic and transmission electron microscopy images. X-PCI is able to resolve the three layers and the architectural organization of cartilage including changes in chondrocyte cell morphology, chondrocyte subgroup distribution and (re-)organization as well as its subtle matrix structures. Conclusions X-PCI captures comprehensive cartilage tissue transformation in its environment and might serve as a tissue-preserving, staining-free and volumetric virtual histology tool for examining and chronicling cartilage behavior in basic research/laboratory experiments of cartilage disease evolution.


Author(s):  
Mehmet Sarikaya ◽  
James M. Howe

The image resolution in bright-field (BF) and dark-field (DF) conventional transmission electron microscopy (TEM) is given by: r = 0.66 CS¼¾¾, where Cs and ¾ are the spherical aberration coefficient of the objective lens and electron wavelength, respectively. Based on this formula, it should be possible to resolve single atoms or clusters of atoms by phase contrast imaging with a highly coherent electron beam and a properly defocused objective lens; this has been demonstrated for both BF and DF imaging. However, for most situations encountered in conventional TEM, the type of information that can be obtained about the specimen is the most important, rather than the instrumental resolution. Atomicresolution microscopy of crystalline specimens relies on phase contrast produced when two or more beams interfere to form an image and this is discussed elsewhere in this symposium. This paper discusses the contrast and resolution when either a single beam or diffuse scattering is used to form an image.


1997 ◽  
Vol 3 (S2) ◽  
pp. 459-460
Author(s):  
G. Duscher ◽  
F. Banhart ◽  
H. Müllejans ◽  
S.J. Pennycook ◽  
M. Rühle

Investigations of the atomic structure of Si-SiO2 interfaces have mostly been performed with high resolution transmission electron microscopy. However, the interpretation of the phase contrast in the amorphous phase at the interface is not unique. While Ourmazd et al. concluded on a crystalline phase at the Si-SiO2 interface, Akatsu and Ohdomari attributed the same contrast to an interface roughness parallel to the incident electrons.We investigated the Si-SiO2 interface by studying the ELNES of the O-K edge with the spatial difference technique with a dedicated STEM with l00kV (VG HB501 UX). Also the interface was studied by Z-contrast imaging with a 300 kV dedicated STEM (VG HB603 U). Silicon wafers (110) were first thermally oxidised to produce a SiO2 layer. The thermally grown oxide was used as a substrate for liquid phase epitaxy of silicon, given two {111} Si-SiO2 interfaces in the sample grown by two different techniques (see fig. 1).


2019 ◽  
Vol 25 (3) ◽  
pp. 563-582 ◽  
Author(s):  
Colin Ophus

AbstractScanning transmission electron microscopy (STEM) is widely used for imaging, diffraction, and spectroscopy of materials down to atomic resolution. Recent advances in detector technology and computational methods have enabled many experiments that record a full image of the STEM probe for many probe positions, either in diffraction space or real space. In this paper, we review the use of these four-dimensional STEM experiments for virtual diffraction imaging, phase, orientation and strain mapping, measurements of medium-range order, thickness and tilt of samples, and phase contrast imaging methods, including differential phase contrast, ptychography, and others.


Author(s):  
Ronald Gronsky

Due to the exceptional performance of most modern commercial transmission electron microscopes, the achievement of phase-contrast imaging resolution in the sub-2Å range is today a routine exercise, provided the samples are compliant. Nonetheless, there remains room for improvement, and the purpose of this manuscript is to highlight procedures that might be employed by the practicing microscopist for advancing conventional high resolution electron microscopy.


2021 ◽  
Vol 118 (50) ◽  
pp. e2108738118
Author(s):  
Matthew Croxford ◽  
Michael Elbaum ◽  
Muthuvel Arigovindan ◽  
Zvi Kam ◽  
David Agard ◽  
...  

Cryo-electron tomography (cryo-ET) allows for the high-resolution visualization of biological macromolecules. However, the technique is limited by a low signal-to-noise ratio (SNR) and variance in contrast at different frequencies, as well as reduced Z resolution. Here, we applied entropy-regularized deconvolution (ER-DC) to cryo-ET data generated from transmission electron microscopy (TEM) and reconstructed using weighted back projection (WBP). We applied deconvolution to several in situ cryo-ET datasets and assessed the results by Fourier analysis and subtomogram analysis (STA).


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