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  • 1995-1999  (2)
  • Gram-Schmidt downdating algorithm  (1)
  • Immunohistochemistry  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Diseases of the colon & rectum 38 (1995), S. 509-513 
    ISSN: 1530-0358
    Keywords: Colon ; Innervation ; Nerves ; Muscle ; Immunohistochemistry ; Constipation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract PURPOSE: This study was designed to investigate neural and muscular features of the colonic wall in patients with severe idiopathic constipation. METHODS: By using quantitative immunohistochemistry, resected specimens from 14 patients with idiopathic chronic constipation and 17 nonobstructed cancer controls were studied. RESULTS: Routine histology revealed no significant histologic abnormality throughout the colon apart from four cases of melanosis coli. Ratio of the thickness of circular to longitudinal muscle was significantly lower in the left colon in constipated subjects. The myenteric plexus appeared morphologically normal in all subjects. S-100 protein, which stains neuronal supporting tissues, demonstrated an increase in the proportion of neural tissue in the myenteric plexus. There was an increased number of PGP-9.5 immunoreactive nerve fibers in the muscularis propria in constipated patients, and this was significantly higher in the ascending and descending colon. CONCLUSION: Intractably constipated patients have alterations in the neural composition of the colonic myenteric plexus and innervation of the circular muscle.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    BIT 36 (1996), S. 166-181 
    ISSN: 1572-9125
    Keywords: QR decomposition downdating ; Gram-Schmidt downdating algorithm ; Householder transformation ; least squares problems ; modified Gram-Schmidt algorithm ; reorthogonalization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract A new algorithm for downdating a QR decomposition is presented. We show that, when the columns in the Q factor from the Modified Gram-Schmidt QR decomposition of a matrixX are exactly orthonormal, the Gram-Schmidt downdating algorithm for the QR decomposition ofX is equivalent to downdating the full Householder QR decomposition of the matrixX augmented by ann ×n zero matrix on top. Using this relation, we derive an algorithm that improves the Gram-Schmidt downdating algorithm when the columns in the Q factor are not orthonormal. Numerical test results show that the new algorithm produces far more accurate results than the Gram-Schmidt downdating algorithm for certain ill-conditioned problems.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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