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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Review of derivatives research 4 (2000), S. 155-188 
    ISSN: 1573-7144
    Keywords: contingent pricing ; option pricing ; option bounds ; arbitrage ; linear programming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract Optionbounds are determined by state discount factors limited by pricesof a riskless bond and the underlying asset. Usually the assethas at least two market-traded options for each maturity, furtherlimiting the factors. Tighter bounds result from incorporatingthe prices of all existing options of the same maturity. Thetightened bounds are particularly applicable to appraising theconsistency of all options trading on a single underlying security,notably index options. Constructed examples indicate a potentialimprovement of eighty percent in bound width; index data revealsa lower reduction, but extensive arbitrage opportunities fromviolations of the tighter bounds.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1530-0358
    Keywords: Hartmann's procedure ; Hartmann's reversal ; Adhesion density ; Operative difficulty
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract PURPOSE: The optimal time for reversal of Hartmann's procedure is controversial. Significant operative difficulty and morbidity have been reported for Hartmann's reversal. The purpose of this study was to examine 11 years' experience with Hartmann's reversal, with particular attention to rate of reversibility, operative difficulty, and timing of reversal. METHODS: Case records of all patients undergoing either Hartmann's procedure or Hartmann's reversal at St. Vincent's Hospital between 1981 and 1991 were examined. Patients having Hartmann's reversal were divided into an early group (before 15 weeks) and a late group (after 15 weeks). These groups were compared in terms of morbidity and mortality, bed stay, and operative difficulty. RESULTS: Hartmann's procedure was performed on 111 patients, mostly for advanced cancer and complicated diverticular disease. Of 96 patients who survived, 50 (52 percent) underwent reversal. Of those with diverticular disease, 40 of 48 (83 percent) underwent reversal. Mortality for Hartmann reversal was 2 percent; anastomotic leak rate 4 percent; and overall complication rate 26 percent. Early reversal was performed in 13 patients and late reversal in 37 patients. There was no difference between these groups in mortality, morbidity, or anastomotic leakage. However, bed stay was longer in the early group and graded operative difficulty greater. In particular, cases in which adhesion density was most severe and in which accidental enterotomy occurred were more common in the early group (P = 0.02, Miettinen's modification of Fisher's exact test). CONCLUSIONS: Hartmann's reversal can be performed with an acceptable morbidity and mortality in most survivors of complicated diverticular disease. Operative difficulty appears to be less after a delay of 15 weeks.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Diseases of the colon & rectum 34 (1991), S. 1079-1084 
    ISSN: 1530-0358
    Keywords: Nd:YAG laser ; Tissue fusion ; Rabbit ; Bowel welding ; Colon anastomosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To assess the possibility of laser anastomosis of the colon, experimental laser closure of colotomies was performed. Transverse colotomies (average 20.7 mm) in New Zealand white rabbits (n = 20) were closed with a 1,064-nm Nd:YAG laser at a pulsating 0.5-W wave of power, using guy sutures to approximate the tissue edges. The laser energy was applied through a specially designed hand piece and hand-held 600-μ m gas-cooled noncontact quartz fiber to produce a satisfactory tissue welding. Similar colotomies were closed using a single layer of interrupted sutures of 5−0 Maxon ® (Davis & Geck, Pearl River, NY) in a control group (n=20). Bursting pressure and index of narrowing were recorded immediately after anastomosis and at 1, 4, and 7 days following surgery. Bursting pressure of the laser-welded closure at 1 day was significantly lower than that of the sutured controls (P 〈0.01); however, all rabbits recovered uneventfully. There was a marked decrease in adhesion formation following laser anastomosis (P 〈 0.05). Conversely, one control rabbit showed functional stenosis at 4 days. Histologic study revealed an accelerated healing in the laser group. The index of narrowing was significantly higher in the laser group than in the control group (P 〈0.05). The completely water-sealed laser anastomosis reduces adhesions and is comparable to conventional suture anastomosis of the colon.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Diseases of the colon & rectum 37 (1994), S. 1198-1204 
    ISSN: 1530-0358
    Keywords: Nd:YAG laser ; Tissue fusion ; Rabbit ; Bowel welding ; Colon anastomosis ; Collagen ; Wound healing ; Wound contraction ; Stricture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract PURPOSE: Our previous experimental work showed the feasibility of colon anastomosis using laser; however, it also revealed a narrowing tendency after laser anastomosis. Long-term observation of the postoperative course of laser anastomosis was planned to assess this point. METHODS: Clinical observation and histologic examination of transverse colotomies (average, 21.2 mm) in New Zealand white rabbits (n=12) closed with a 1,064-nm neodymiumyttrium aluminum garnet (Nd:YAG) laser were carried out up to the third postoperative month, compared with closure of colotomies using a single layer of interrupted sutures of 5-0 Maxon® (Davis & Geck, Pearl River, NY) in a control group (n=12). RESULTS: Whereas the narrowing tendency was observed up to one month after the operation in the laser group (P〈0.05), it disappeared at three months following the operation without causing abnormal weight loss during the experiment. Simultaneously, there was again a marked decrease in adhesion formation following laser anastomosis (P〈0.01). Collagen fibers were observed earlier in the laser group. CONCLUSIONS: An earlier commencement of collagen synthesis after laser anastomosis was proved. A narrowing tendency, which was observed from seven days to one month postoperatively, disappeared at three months after laser anastomosis without exerting any effect on growth.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1585-1591 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A simple design technique for heterogeneous distillation columns has been developed. The underlying geometric conditions which govern minimum reflux are shown to share certain common features with homogeneous distillations, but differ in some important respects. It is shown that heterogeneous columns display some unusual sensitivities to the design parameters. The most notable being the drastic swings in the composition and temperature profiles with very small changes in the level of trace impurities in the product stream.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1592-1601 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Various strategies for sequencing heterogeneous azeotropic distillations have been explored. The design and optimization of these systems by simulation-based methods is generally acknowledged to be a very difficult problem (Kingsley and Lucia, 1988). In this article, a simple and accurate design and optimization procedure has been developed. The method does not involve any recycle convergence loops and has been applied successfully to several test problems. Unlike the simulation-based methods, our method is robust to changes in the system optimization variables (e.g., reflux ratio in the azeotropic column).In order to demonstrate the method, we present design and optimization results for the dehydration of ethanol using a benzene entrainer. Our optimal designs consume significantly less energy than state-of-the-art designs reported in the literature.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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