Functional morphology and fiber types of the masseter muscles of two caviomorph rodents with contrasting lifestyles,
            Ctenomys talarum
            (Ctenomyidae) and
            Cavia aperea
            (Caviidae)

The excellent preservation of the molluscan fauna from the Gosport Sand (Eocene) at Little Stave Creek, Alabama, has made it possible to describe the preserved color patterns of 15 species. In this study the functional significance of these color patterns is tested in the context of the current adaptationist controversy. The pigment of the color pattern is thought to be a result of metabolic waste disposal. Therefore, the presence of the pigment is functional, although the patterns formed by the pigment may or may not have been adaptive. In this investigation the criteria proposed by Seilacher (1972) for testing the functionality of color patterns were applied to the Gosport fauna and the results compared with life mode as interpreted from knowledge of extant relatives and functional morphology. Using Seilacher's criteria of little ontogenetic and intraspecific variability, the color patterns appear to have been functional. However, the functional morphology studies indicate an infaunal life mode which would preclude functional color patterns. Particular color patterns are instead interpreted to be the result of historical factors, such as multiple adaptive peaks or random fixation of alleles, or of architectural constraints including possibly pleiotropy or allometry. The low variability of color patterns, which was noted within species and genera, suggests that color patterns may also serve a useful taxonomic purpose.

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Structural Organization and Distribution of Fiber Types in Extraocular Muscles of Cats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100093420 ◽

1972 ◽

Vol 30 ◽

pp. 34-35

Author(s):

Asish C. Nag ◽

Lee D. Peachey

Keyword(s):

Fiber Type ◽

Light And Electron Microscopy ◽

Small Diameter ◽

Extraocular Muscles ◽

Fiber Types ◽

Distinctive Features ◽

Superior Rectus ◽

Adult Cats ◽

Different Diameters ◽

Orbital Region

Cat extraocular muscles consist of two regions: orbital, and global. The orbital region contains predominantly small diameter fibers, while the global region contains a variety of fibers of different diameters. The differences in ultrastructural features among these muscle fibers indicate that the extraocular muscles of cats contain at least five structurally distinguishable types of fibers.Superior rectus muscles were studied by light and electron microscopy, mapping the distribution of each fiber type with its distinctive features. A mixture of 4% paraformaldehyde and 4% glutaraldehyde was perfused through the carotid arteries of anesthetized adult cats and applied locally to exposed superior rectus muscles during the perfusion.

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Use of EDS mapping to characterize thermochemical stability of fibers in intermetallic matrix composites

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010012120x ◽

1992 ◽

Vol 50 (1) ◽

pp. 160-161

Author(s):

John R. Porter

Keyword(s):

Spatial Information ◽

Beam Current ◽

Fiber Types ◽

Ceramic Fibers ◽

Dye Transfer ◽

Science Center ◽

Commercial Development ◽

Nih Image ◽

Intermetallic Matrix Composites ◽

Thermochemical Stability

New ceramic fibers, currently in various stages of commercial development, have been consolidated in intermetallic matrices such as γ-TiAl and FeAl. Fiber types include SiC, TiB2 and polycrystalline and single crystal Al2O3. This work required the development of techniques to characterize the thermochemical stability of these fibers in different matrices.SEM/EDS elemental mapping was used for this work. To obtain qualitative compositional/spatial information, the best realistically achievable counting statistics were required. We established that 128 × 128 maps, acquired with a 20 KeV accelerating voltage, 3 sec. live time per pixel (total mapping time, 18 h) and with beam current adjusted to give 30% dead time, provided adequate image quality at a magnification of 800X. The maps were acquired, with backgrounds subtracted, using a Noran TN 5500 EDS system. The images and maps were transferred to a Macintosh and converted into TIFF files using either TIFF Maker, or TNtolMAGE, a Microsoft QuickBASIC program developed at the Science Center. From TIFF files, images and maps were opened in either NIH Image or Adobe Photoshop for processing and analysis and printed from Microsoft Powerpoint on a Kodak XL7700 dye transfer image printer.

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