scholarly journals Low-dose scanning electron diffraction and pharmaceutical nanostructure

2018 ◽  
Vol 74 (a2) ◽  
pp. e83-e84
Author(s):  
Duncan Johnstone ◽  
Christopher S. Allen ◽  
Mohsen Danaie ◽  
Royston C. B. Copley ◽  
Anais Lafontaine ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Low Dose ◽  
Scanning Electron

scholarly journals Low-Dose Scanning Electron Diffraction Microscopy of Mechanochemically Nanostructured Pharmaceuticals

2019 ◽  
Vol 25 (S2) ◽  
pp. 1746-1747 ◽  
Author(s):  
Duncan N. Johnstone ◽  
Christopher S. Allen ◽  
Mohsen Danaie ◽  
Royston C.B. Copley ◽  
Jeffrey Brum ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Low Dose ◽  
Diffraction Microscopy ◽  
Electron Diffraction Microscopy ◽  
Scanning Electron

Removal of inelastically scattered electrons substantially increases phase contrast on frozen-hydrated molecules

1987 ◽  
Vol 45 ◽  
pp. 652-653
Author(s):  
John P. Langmore ◽  
Brian D. Athey
Keyword(s):  
Electron Diffraction ◽  
Phase Contrast ◽  
Low Dose ◽  
Dark Field ◽  
Biological Structure ◽  
Bright Field ◽  
Low Contrast ◽  
Negative Stain ◽  
The Difference ◽  
Better Than

Although electron diffraction indicates better than 0.3nm preservation of biological structure in vitreous ice, the imaging of molecules in ice is limited by low contrast. Thus, low-dose images of frozen-hydrated molecules have significantly more noise than images of air-dried or negatively-stained molecules. We have addressed the question of the origins of this loss of contrast. One unavoidable effect is the reduction in scattering contrast between a molecule and the background. In effect, the difference in scattering power between a molecule and its background is 2-5 times less in a layer of ice than in vacuum or negative stain. A second, previously unrecognized, effect is the large, incoherent background of inelastic scattering from the ice. This background reduces both scattering and phase contrast by an additional factor of about 3, as shown in this paper. We have used energy filtration on the Zeiss EM902 in order to eliminate this second effect, and also increase scattering contrast in bright-field and dark-field.

Dynamic low-dose electron diffraction and imaging of phase transitions in polymers

1993 ◽  
Vol 51 ◽  
pp. 890-891
Author(s):  
David C. Martin ◽  
Jun Liao
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Electron Diffraction ◽  
Low Dose ◽  
Dark Field ◽  
Continuous Change ◽  
Selected Area Electron Diffraction ◽  
Resolution Electron ◽  
Chain Axis ◽  
High Resolution Electron Micrographs

By careful control of the electron beam it is possible to simultaneously induce and observe the phase transformation from monomer to polymer in certain solid-state polymcrizable diacetylenes. The continuous change in the crystal structure from DCHD diacetylene monomer (a=1.76 nm, b=1.36 nm, c=0.455 nm, γ=94 degrees, P2l/c) to polymer (a=1.74 nm, b=1.29 nm, c=0.49 nm, γ=108 degrees, P2l/c) occurs at a characteristic dose (10−4C/cm2) which is five orders of magnitude smaller than the critical end point dose (20 C/cm2). Previously we discussed the progress of this phase transition primarily as observed down the [001] zone (the chain axis direction). Here we report on the associated changes of the dark field (DF) images and selected area electron diffraction (SAED) patterns of the crystals as observed from the side (i.e., in the [hk0] zones).High resolution electron micrographs (HREM), DF images, and SAED patterns were obtained on a JEOL 4000 EX HREM operating at 400 kV.

Reflexion Scanning Electron Diffraction from Growing Films

Nature ◽  
1967 ◽  
Vol 214 (5083) ◽  
pp. 77-78 ◽  
Author(s):  
P. I. TILLETT ◽  
C. W. B. GRIGSON
Keyword(s):  
Electron Diffraction ◽  
Scanning Electron

scholarly journals Low-flux scanning electron diffraction reveals substructures inside the ordered membrane domain

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Masanao Kinoshita ◽  
Shimpei Yamaguchi ◽  
Nobuaki Matsumori
Keyword(s):  
Phase Separation ◽  
Electron Diffraction ◽  
Electron Flux ◽  
Chain Packing ◽  
Packing Structure ◽  
Carbon Chains ◽  
Disordered Phase ◽  
Crystallographic Axes ◽  
Beam Damage ◽  
Scanning Electron

AbstractOrdered/disordered phase separation occurring in bio-membranes has piqued researchers’ interest because these ordered domains, called lipid rafts, regulate important biological functions. The structure of the ordered domain has been examined with artificial membranes, which undergo macroscopic ordered/disordered phase separation. However, owing to technical difficulties, the local structure inside ordered domains remains unknown. In this study, we employed electron diffraction to examine the packing structure of the lipid carbon chains in the ordered domain. First, we prepared dehydrated monolayer samples using a rapid-freezing and sublimation protocol, which attenuates the shrinkage of the chain-packing lattice in the dehydration process. Then, we optimised the electron flux to minimise beam damage to the monolayer sample. Finally, we developed low-flux scanning electron diffraction and assessed the chain packing structure inside the ordered domain formed in a distearoylphosphatidylcholine/dioleoylphosphatidylcholine binary monolayer. Consequently, we discovered that the ordered domain contains multiple subdomains with different crystallographic axes. Moreover, the size of the subdomain is larger in the domain centre than that near the phase boundary. To our knowledge, this is the first study to reveal the chain packing structures inside an ordered domain.

A study of the high-Cu Al–Cu–Co decagonal phase

1993 ◽  
Vol 8 (7) ◽  
pp. 1473-1476 ◽  
Author(s):  
B. Grushko
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Diffraction ◽  
Diffuse Scattering ◽  
Nonequilibrium State ◽  
Zone Axis ◽  
Decagonal Phase ◽  
Diffraction Patterns ◽  
Scanning Electron

The decagonal phase was studied by transmission and scanning electron microscopy in an Al62Cu24Co14 alloy annealed at 550–850 °C. The electron diffraction patterns of the decagonal phase exhibited weak quasiperiodic odd-n reflections in the [1-2100] zone axis corresponding to the equilibrated structure. The relative intensities of these reflections were significantly lower in the Al62Cu24Co14 than in the Al68Cu11Co21 decagonal phase. Diffuse scattering observed previously at the same positions can be related to a nonequilibrium state of the decagonal phase.

scholarly journals Scanning electron diffraction using the pnCCD (S)TEM Camera

2016 ◽  
pp. 641-642
Author(s):  
Robert Ritz ◽  
Martin Huth ◽  
Sebastian Ihle ◽  
Julia Schmidt ◽  
Martin Simson ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Scanning Electron
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