Crystal orientation in the shell of the domestic fowl: An electron diffraction study

Perrott, H. R.; Scott, V. D.; Board, R. G.

doi:10.1007/bf02409423

Cited by 19 publications

(11 citation statements)

References 10 publications

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“…In an analysis of texture, Perrott et al (1981) found using TEM and diffraction that the calcite columns within the palisade layer consisted of crystallites of diameter 20-30 mm. Also, Cain & Heyn (1964) found the mineral particle sizes to be 200 mm by using the number of diffraction A typical X-ray transmission image of an eggshell, obtained using the defocused beam.…”

Section: Resultsmentioning

confidence: 99%

“…This has been found in all the shells studied and is a feature that cannot easily be explained from conventional morphological studies. As the vertical crystal layer is approximately 8 mm in length (Perrott et al, 1981), there is a chance that this area of the eggshell was not scanned owing to the size of the scanning steps used being 16 mm. However, as the cuticle is approximately 10 mm, at least one SAXS pattern was captured from these adjoining parts of the eggshell.…”

Section: Figurementioning

confidence: 99%

“…However, as the cuticle is approximately 10 mm, at least one SAXS pattern was captured from these adjoining parts of the eggshell. Perrott et al (1981) also stated that the only layer that showed any sort of preferred orientation was the surface crystal layer. This also coincides with the results here regarding the outer part of the shell showing a scattering distribution that indicates an orientation at approximately 36 .…”

Section: Figurementioning

confidence: 99%

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Microfocus X-ray scattering investigations of eggshell nanotexture

Lammie

Bain

Wess

2005

J Synchrotron Radiat

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The avian eggshell is a highly ordered calcitic bioceramic composite, with both inorganic and organic constituents. The interactions between the inorganic and organic components within the structure are poorly understood but are likely to occur at the nanometre level. Thus structural variation at this level may impinge on the overall structural integrity and mechanical performance of the eggshell, and therefore analysis at this level is fundamental in fully understanding this ordered structure. In this study, structural changes in the mineral crystallites were investigated by microfocus small-angle X-ray scattering (mSAXS) using synchrotron radiation. Small-angle X-ray scattering (SAXS) can be used to investigate structures on the nanometre scale such as size, shape, arrangement and internal porosity. A microfocused X-ray beam, 1.5 mm vertically by 7 mm, was used to produce vertical linear scans of the eggshell section. SAXS patterns were taken from the eggshell membrane (inner surface of the eggshell) to the cuticle (outer surface of the eggshell). This allowed textural variations within the eggshell to be mapped. The scattering intensity profile was then used to derive the dimension of scattering objects that define the nanotexture. The nanotexture observed may result from the presence of the organic matrix, which is embedded as intracrystalline particles producing voids within the calcified framework of large (> 1 mm) calcite crystals. Porod analysis revealed the average size of a scattering interface to be approximately 4.5 nm with small changes that had a depth-dependent variation. These were largest at the mammillary layer/ membrane boundary. The palisade layer displayed a small upward trend in size of scattering object. Parallel scans showed that the textural variations observed within the palisade layer are significant and indicate local subtextures. In addition, many of the patterns exhibit diffuse scattering streaks that could result from reflectivity from the larger crystallite interfaces. Changes in the orientation of diffuse streaks were observed within the different layers, the membranes, mammillary layer, palisade layer, vertical crystal layer and cuticle, indicating certain preferred orientations of the crystallites within the layers. The nanotextural variations that are apparent could have implications at the macroscopic level of the resulting eggshell.

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Section: Resultsmentioning

confidence: 99%

Section: Figurementioning

confidence: 99%

Section: Figurementioning

confidence: 99%

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Microfocus X-ray scattering investigations of eggshell nanotexture

Lammie

Bain

Wess

2005

J Synchrotron Radiat

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“…By contrast, electron diffraction methods allow the orientation of only a small number of crystals to be observed. It is impossible to draw general conclusions about the overall crystalline orientation throughout the shell when results are consolidated from only a few crystals taken from several different specimens, as was the case in the work of Perrott et al (1981). Only 8 specimens of the surface layer were examined; the orientations of a total of only 19 crystals were determined, and a tendency for the ( 104) planes to lie parallel to the surface was noted.…”

Section: Discussionmentioning

confidence: 98%

Development of preferred orientation in the eggshell of the domestic fowl

Sharp¹,

Silyn-Roberts²

1984

Biophysical Journal

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Preferred orientation in the shell of the domestic fowl is shown by x-ray diffractometry to develop gradually throughout the shell, beginning immediately after the start of shell deposition and reaching a maximum at the exterior surface. Only 2 out of 20 shells examined exhibited a single preferred orientation: This was one in which the pole of the (001) plane lies parallel to the shell surface normal. The remaining shells had two preferred orientations present simultaneously, one in which the (001) pole is parallel and the other in which the (104) pole is parallel to the surface normal. Previous work has resulted in conclusions that are in conflict with these; they are discussed in relation to the present work.

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“…Moreover, there is no obvious morphological discontinuity in the central layer in those of the ratite shells that show a sudden reversal of a high degree of preferred orientation. The central layer, which has previously been believed to be composed of randomly oriented calcite (Perrott et al, 1981) can therefore accommodate both the development of a very high degree of texture and its subsequent reversal whilst appearing to be structurally homogeneous (Plate I(c), (d)).…”

Section: Discussionmentioning

confidence: 99%

Preferred orientation of calcite in the ratite and tinamou eggshells

Silyn-Roberts

Sharp

1985

Journal of Zoology

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With 1 plate and 5 figures in the text) Using X-ray diffractometry, the development of preferred orientation was studied in one species from each of the extant ratite families, from two moas and two tinamous and, as a preliminary comparison, from representative species from 16 of the other carinate orders. A preferred orientation begins to develop immediately after the start of shell deposition, and in all shells studied was one in which the (001) planes tend to lie parallel to the shell surface. The degree of (001) texture that develops in the ratite and tinamou shells is greater than that developed in the other carinate orders. Development in the ostrich, kiwi and tinamou is uninterrupted so that there is a very high degree of (001) preferred orientation at the exteriors of the shells. In the Emu, cassowary, rhea and the two moa species, a very high degree of (001) texture reverses gradually within the central layer of the shell, and in some species this is accompanied by the development of a very weak (104) preferred orientation. The weak (001) textures observed in the shells of the 20 species from the carinate orders other than the Tinamiformes develop slowly and without interruption through the shell; in four species a weak (104) texture develops simultaneously to that of the (OOI), forminga double texture similar to that already reported in the majority of shells of the domestic fowl.

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Crystal orientation in the shell of the domestic fowl: An electron diffraction study

Cited by 19 publications

References 10 publications

Microfocus X-ray scattering investigations of eggshell nanotexture

Microfocus X-ray scattering investigations of eggshell nanotexture

Development of preferred orientation in the eggshell of the domestic fowl

Preferred orientation of calcite in the ratite and tinamou eggshells

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