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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European biophysics journal 26 (1997), S. 393-404 
    ISSN: 1432-1017
    Keywords: Key words Threshold detection ; Statistical filtering ; Model ranking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Different statistical or low-pass filters may be used for the idealization of ion channel data. We address the problem of predicting optimal filter parameters, represented by a threshold test-value for statistical filters and by a cut-off frequency for low-pass filters. Optimal idealization is understood in the sense of maximal similarity between recovered and real signals. Special procedures are suggested to quantitatively characterize the difference between the recovered and the real signals, the latter being known for simulated data. These procedures, called objective criteria, play the role of referees in estimating the performance of different predictive optimality criteria. We have tested standard Akaike's AIC and its modification by Rissanen, MDL. Both gave unsatisfactory results. We have shown analytically, that the Akaike-type criterion, based on the use of a certain penalty for the log likelihood function per transition, indicates the correct optimum point only if the penalty is set equal to half the optimal threshold. As the latter varies significantly for different data sets, this criterion is not particularly helpful. A new universal predictive optimality criterion, valid for real data and any idealization method, is suggested. It is formally similar to AIC, but instead of log likelihood it uses the doubled number of false transitions. The predictive power of the new criterion is demonstrated with different types of data for Hinkley and 50% amplitude methods.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Diseases of the colon & rectum 42 (1999), S. 626-630 
    ISSN: 1530-0358
    Keywords: Continent perineal colostomy ; Abdominoperineal resection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract PURPOSE: For patients with distal rectal or anal tumors, quality of life can be compromised after abdominoperineal resection and iliac colostomy. This study examines our experience with a continent perineal colostomy constructed from a colonic smooth-muscle cuff wrap. METHODS: Between 1987 and 1996, 63 patients with distal rectal or anal tumors (0–5 cm from the anal verge) underwent abdominoperineal resection and construction of a colonic smooth-muscle cuff at the site of the perineal colostomy. Postoperatively, all patients required colonic irrigations daily or every two days. The complications, continence at 6 and 12 months, and degree of satisfaction were prospectively evaluated using a standard questionnaire. RESULTS: Early complications included partial perineal dehiscence in 14 (22.5 percent) patients, pelvic abscess in 2 (3 percent) patients, and colostomy necrosis in 1 (1.6 percent) patient. Late complications were colostomy stricture in 7 (11.8 percent) patients, perineal sinus tract in 4 (6.7 percent) patients, and mucosal prolapse in 12 (20 percent) patients. Satisfactory continence (complete continence to stool and incontinence to gas) at 6 and 12 months was achieved in 30 (55.6 percent) and 27 (59 percent) patients, respectively. Patient satisfaction was noted in 85 percent. CONCLUSION: Continent perineal colostomy can serve as an alternative to conventional iliac colostomy. Most patients were satisfied. The modest complication rate can be minimized with patient selection.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-4475
    Keywords: 9(10H)-Acridinone ; Alkylation ; Phase-transfercatalysis ; Prototropic rearrangement ; X-Ray
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Reaction of 9(10H)-acridinone (2) with 3-chloro-3-phenyl-1-propyne under PTC conditions affords 1-methyl-2-phenyl-6H-pyrrolo[3,2,1-de]acridin-6-one (1 b), 10-(2-chloro-1-methyl-2-phenyl-ethenyl)-9(10H)-acridinone (4), 10-(3-phenyl-1-propynyl)-9(10H)-acridinone (7), and 10-(4-methylene-2,3-diphenyl-2-cyclobuteneylidenemethyl)-9(10H)-acridinone (5). The structure of the last compound which crystallizes in the triclinic system with the space group $$P\bar 1$$ , was confirmed by X-ray diffraction. Under the same conditions 10-(3-phenyl-2-propynyl)-9(10H)-acridinone (3) and 10-(3-phenyl-1-propynyl)-9(10H)-acridinone (6) were obtained from 9(10H)-acridinone (2) and 3-bromo-1-phenyl-1-propyne.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1434-4475
    Keywords: Pyrano[3,2-c]quinoline-alkaloids ; 4-Hydroxyquinoline-2-ones ; Alkylation ; Phase-transfer-catalysis ; Sigmatropic rearrangement ; “Späth type” chromene synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The pyrano-cyclisation of 4-hydroxy-(1-methyl)-1H-quinoline-2-one with 3-chlor-3-methylbut-1-yne, supposed to proceed via an ether or vinyl intermediate, is studied by alkylating different 4-hydroxyquinolines. The nine derivatives characterized favour the ether-pathway (“Späth type” chromene synthesis).
    Type of Medium: Electronic Resource
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