Abstract：
:The Contrast Transfer Function (CTF) of an image, which modulates images taken from a Transmission Electron Microscope (TEM), is usually determined from the radial average of the power spectrum of the image (Frank, J., Three-dimensional Electron Microscopy of Macromolecular Assemblies, Oxford University Press, Oxford, 2006). The CTF is primarily defined by the defocus. If the defocus estimate is accurate enough then it is possible to demodulate the image, which is popularly known as the CTF correction. However, it is known that the radial average is somewhat attenuated if the image is astigmatic (see Fernando, K.V., Fuller, S.D., 2007. Determination of astigmatism in TEM images. Journal of Structural Biology 157, 189-200) but this distortion due to astigmatism has not been fully studied or understood up to now. We have discovered the exact mathematical relationship between the radial averages of TEM images with and without astigmatism. This relationship is determined by a zeroth order Bessel function of the first kind and hence we can exactly quantify this distortion in the radial averages of signal and power spectra of astigmatic images. The argument to this Bessel function is similar to an aberration function (without the spherical aberration term) except that the defocus parameter is replaced by the differences of the defoci in the major and minor axes of astigmatism. The ill effects due this Bessel function are twofold. Since the zeroth order Bessel function is a decaying oscillatory function, it introduces additional zeros to the radial average and it also attenuates the CTF signal in the radial averages. Using our analysis, it is possible to simulate the effects of astigmatism in radial averages by imposing Bessel functions on idealized radial averages of images which are not astigmatic. We validate our theory using astigmatic TEM images.
journal_name
J Struct Bioljournal_title
Journal of structural biologyauthors
Fernando KVdoi
10.1016/j.jsb.2008.06.012subject
Has Abstractpub_date
2008-10-01 00:00:00pages
49-59issue
1eissn
1047-8477issn
1095-8657pii
S1047-8477(08)00159-7journal_volume
164pub_type
杂志文章abstract：:Beam damage is the main resolution-limiting factor when biological particles are observed by cryoelectron microscopy in a thin vitrified solution film. Furthermore, the low contrast of the specimen frequently makes observation difficult and limits the possibility of image processing. Cryo-negative staining, in which t...
journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1016/s1047-8477(02)00035-7
更新日期：2002-06-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1016/j.jsb.2018.03.011
更新日期：2018-08-01 00:00:00
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pub_type： 杂志文章
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更新日期：2017-06-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
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更新日期：2003-12-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
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更新日期：1999-12-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章,评审
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更新日期：2006-11-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
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更新日期：2012-07-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1006/jsbi.1999.4097
更新日期：1999-04-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
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更新日期：2012-02-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1016/j.jsb.2005.03.010
更新日期：2005-07-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1016/j.jsb.2011.11.019
更新日期：2012-02-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1016/j.jsb.2006.08.021
更新日期：2007-05-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1016/j.jsb.2015.09.020
更新日期：2015-12-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1016/j.jsb.2014.01.004
更新日期：2014-03-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1016/j.jsb.2014.02.001
更新日期：2014-04-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1016/j.jsb.2019.09.011
更新日期：2019-12-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1016/j.jsb.2010.05.011
更新日期：2010-12-01 00:00:00
abstract：:Single particle electron cryomicroscopy (cryo-EM) allows for structures of proteins and protein complexes to be determined from images of non-crystalline specimens. Cryo-EM data analysis requires electron microscope images of randomly oriented ice-embedded protein particles to be rotated and translated to allow for co...
journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1016/j.jsb.2015.06.014
更新日期：2015-11-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1016/j.jsb.2009.06.018
更新日期：2009-12-01 00:00:00
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pub_type： 杂志文章,评审
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更新日期：2003-04-01 00:00:00
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journal_title：Journal of structural biology
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doi：10.1006/jsbi.1995.1009
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pub_type： 杂志文章
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更新日期：2004-09-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1006/jsbi.1996.0079
更新日期：1996-09-01 00:00:00
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更新日期：2011-09-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章,评审
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更新日期：2002-10-01 00:00:00
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pub_type： 杂志文章
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更新日期：2003-03-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
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更新日期：2011-02-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
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更新日期：2007-12-01 00:00:00
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journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1016/j.jsb.2008.04.007
更新日期：2008-07-01 00:00:00
abstract：:Gap junctions containing extensive, highly ordered crystalline arrays of hexagonally packed connexons have been isolated from the hepatopancreas of the arthropod, Homarus americanus (American lobster). The structure of such junctions has been studied to a resolution of approximately 25 A in three dimensions by electro...
journal_title：Journal of structural biology
pub_type： 杂志文章
doi：10.1016/1047-8477(91)90075-8
更新日期：1991-06-01 00:00:00
