Maximum diameter of the rod-shaped specimen for transmission electron microtomography without the “missing wedge”

Kato, Mitsuro; Kawase, Noboru; Kaneko, Takeshi; Toh, Shoichi; Matsumura, Shuichi; Jinnai, Hiroshi

doi:10.1016/j.ultramic.2007.06.004

Cited by 34 publications

(15 citation statements)

References 22 publications

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“…7B–D). Image features would be expected to be most visible near the tube walls where the ice thickness is lowest, and a previous report confirms this effect [58]. These linear features appear to be separated by a constant distance of approximately 30–35 nm, consistent with previous tomographic observations of the double membrane envelopes of C. crescentus cells [59].…”

Section: Resultssupporting

confidence: 86%

A cylindrical specimen holder for electron cryo-tomography

Palmer

Löwe

2014

Ultramicroscopy

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The use of slab-like flat specimens for electron cryo-tomography restricts the range of viewing angles that can be used. This leads to the “missing wedge” problem, which causes artefacts and anisotropic resolution in reconstructed tomograms. Cylindrical specimens provide a way to eliminate the problem, since they allow imaging from a full range of viewing angles around the tilt axis. Such specimens have been used before for tomography of radiation-insensitive samples at room temperature, but never for frozen-hydrated specimens. Here, we demonstrate the use of thin-walled carbon tubes as specimen holders, allowing the preparation of cylindrical frozen-hydrated samples of ribosomes, liposomes and whole bacterial cells. Images acquired from these cylinders have equal quality at all viewing angles, and the accessible tilt range is restricted only by the physical limits of the microscope. Tomographic reconstructions of these specimens demonstrate that the effects of the missing wedge are substantially reduced, and could be completely eliminated if a full tilt range was used. The overall quality of these tomograms is still lower than that obtained by existing methods, but improvements are likely in future.

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Section: Resultssupporting

confidence: 86%

A cylindrical specimen holder for electron cryo-tomography

Palmer

Löwe

2014

Ultramicroscopy

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“…Several approaches were used in the past for thickness measurements of thin foils, for example indirect knowledge of the specimens’ geometry (Feja & Aebi, 1999; Plitzko & Mayer, 1999; Nakafuji et al , 2001; Lee et al , 2002; Jin & Wang, 2006; Kato et al , 2008). However, these techniques are either limited to a specific type of material (e.g.…”

Section: Introductionmentioning

confidence: 99%

An experimental method for calibration of the plasmon mean free path

Meltzman

Kauffmann

Thangadurai

et al. 2009

Journal of Microscopy

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SummaryTransmission electron microscopy specimens in the form of elongated, conical needles were made using a dual-beam focused ion beam system, allowing the specimen thickness to be geometrically determined for a range of thickness values. From the same samples electron energy loss maps were acquired and the plasmon mean free path (λ) for inelastic scattering was determined experimentally from the measured values of specimen thickness. To test the method λ was determined for Ni (174 ± 17 nm), α-Al 2 O 3 (143 ± 14 nm), Si (199 ± 20 nm) and amorphous SiO 2 (238 ± 12 nm), and compared both to experimental values of λ taken from the literature and to calculated values. The calculated values of λ significantly underestimate the true sample thickness for high accelerating voltages (300 kV) and large collection angles. A linear dependence of λ on thickness was confirmed for t/λ < 0.5-0.6, but this method also provides an approach for calibrating λ at sample thicknesses for which multiple scattering occurs, thus expanding the thickness range over which electron energy loss spectroscopy can be used to determine the absolute sample thickness (t/λ > 0.6). The experimental method proposed in this contribution offers a means to calibrate λ for any type of material or phase that can be milled using a focused ion beam system.

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“…To that end, we have undertaken electron tomography 14 on rubber composite materials with a range of filler volume fractions, using pillar-shaped samples 15 16 produced using a focussed ion beam instrument (FIB) to minimise resolution loss due to occlusion at high tilt angles. In contrast to most previous electron microscopy of this material type 17 , we use high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) to provide images with high-contrast 18 , improved resolution for relatively thick samples 19 and, where possible, diffraction contrast (from crystalline silica particles) is minimised 14 .…”

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confidence: 99%

Electron tomography provides a direct link between the Payne effect and the inter-particle spacing of rubber composites

Staniewicz

Vaudey

Degrandcourt

et al. 2014

Sci Rep

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Rubber-filler composites are a key component in the manufacture of tyres. The filler provides mechanical reinforcement and additional wear resistance to the rubber, but it in turn introduces non-linear mechanical behaviour to the material which most likely arises from interactions between the filler particles, mediated by the rubber matrix. While various studies have been made on the bulk mechanical properties and of the filler network structure (both imaging and by simulations), there presently does not exist any work directly linking filler particle spacing and mechanical properties. Here we show that using STEM tomography, aided by a machine learning image analysis procedure, to measure silica particle spacings provides a direct link between the inter-particle spacing and the reduction in shear modulus as a function of strain (the Payne effect), measured using dynamic mechanical analysis. Simulations of filler network formation using attractive, repulsive and non-interacting potentials were processed using the same method and compared with the experimental data, with the net result being that an attractive inter-particle potential is the most accurate way of modelling styrene-butadiene rubber-silica composite formation.

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Maximum diameter of the rod-shaped specimen for transmission electron microtomography without the “missing wedge”

Cited by 34 publications

References 22 publications

A cylindrical specimen holder for electron cryo-tomography

A cylindrical specimen holder for electron cryo-tomography

An experimental method for calibration of the plasmon mean free path

Electron tomography provides a direct link between the Payne effect and the inter-particle spacing of rubber composites

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