ISSN:
1435-1536
Keywords:
Image analysis
;
electron microscopy
;
cellulose protofibrils
;
phase contrast
;
transfer function
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Electron microscope images of parallel arrays of Ramie cellulose protofibrils, obtained at various levels of defocus, are discussed in terms of phase contrast. The optical diffraction pattern of appropriately defocused images shows discrete maxima in the resolution range of 2–5 nm. The pattern is dominated by strong equatorial reflections arising from the lateral spacing of the protofibrils which is about 5 nm. From the observed reciprocal lattice net, it is concluded that the protofibrils are characterized by some form of axial texture that repeats with a periodicity of about 6 nm. The lattice reflections in the optical diffraction pattern are shown to be essentially invariant over a wide range of defocusing conditions. From this it is inferred that the pattern arises from real object order. It is emphasized that the optical diffraction pattern derives from gross structural features related to the morphology of the protofibrils and not from their internal structure.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01458967
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