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D M Shotton

Publications and source records attributed to D M Shotton.

40 records · Page 3Linked to original sources
PubMedDate not supplied

Quantitative freeze-fracture studies of membrane changes in chicken muscular dystrophy.

Muscular dystrophy induces extensive changes in the patterning of sarcolemmal caveolae of fast-twitch fibers from the chicken posterior latissimus dorsi (PLD) muscle, which in healthy fibers are arranged in striking bands over the myofibrillar I-bands. In dystrophic fibers the caveolae lack this patterned arrangement, and instead are dispersed over the entire sarcolemma, are irregular in shape, and are more numerous in older birds. Quantitative analysis of these differences provides three independent numerical indices of the dystrophic state and suggests that constraints responsible for normal patterning are lost in diseased fibers. These observations support theories that defects of the muscle plasma membrane are important for dystrophic pathogenesis. In contrast, the sarcolemma of slow tonic fibers from anterior latissimus dorsi (ALD) and metapatagialis latissimus dorsi (MLD) muscles have randomly dispersed caveolae whose appearance and distribution are unaffected by the disease.

Animals↗
PubMedDate not supplied

Video on the Internet: An introduction to the digital encoding, compression, and transmission of moving image data.

In this paper, we seek to provide an introduction to the fast-moving field of digital video on the Internet, from the viewpoint of the biological microscopist who might wish to store or access videos, for instance in image databases such as the BioImage Database (http://www.bioimage.org). We describe and evaluate the principal methods used for encoding and compressing moving image data for digital storage and transmission over the Internet, which involve compromises between compression efficiency and retention of image fidelity, and describe the existing alternate software technologies for downloading or streaming compressed digitized videos using a Web browser. We report the results of experiments on video microscopy recordings and three-dimensional confocal animations of biological specimens to evaluate the compression efficiencies of the principal video compression-decompression algorithms (codecs) and to document the artefacts associated with each of them. Because MPEG-1 gives very high compression while yet retaining reasonable image quality, these studies lead us to recommend that video databases should store both a high-resolution original version of each video, ideally either uncompressed or losslessly compressed, and a separate edited and highly compressed MPEG-1 preview version that can be rapidly downloaded for interactive viewing by the database user.

Algorithms↗