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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Amino acids 6 (1994), S. 283-293 
    ISSN: 1438-2199
    Keywords: Amino acids ; Chronic renal failure ; Plasma ; Urine ; D-amino acids ; CAPD ; D-Tyrosine ; D-Phenylalanine ; Haemodialysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Total D-amino acids were measured in plasma for 20 non-dialysed patients (creatinine clearance 〈 12 ml/minute), 20 on CAPD, 20 on haemodialysis and 20 normals. Plasma D-tyrosine and D-phenylalanine were measured in 8 of each group by HPLC. Total D-amino acids, D-tyrosine and D-phenylalanine were significantly greater for patients than normals. D-amino acids and D-tyrosine correlated with creatinine and were decreased during HD. During dialysis, the mean losses for D-tyrosine and D-phenylalanine were similar, about 0.2 mg/CAPD exchange and 3 mg/4 hour haemodialysis (i.e. 2% of the total amino acid, as in plasma). Clearance was unaffected by stereochemical configuration. Urinary losses/24 hour in the non-dialysed patients were 0.35 mg D-tyrosine and 0.25 mg D-phenylalanine. Clearance for D-phenylalanine was greater than for the L-enantiomer. Increases in D-amino acids in renal failure are probably due to depletion of D-amino acid oxidase, but may be enhanced by a D-amino acid rich diet, peptide antibiotics and D-amino acid oxidase inhibiting drugs and metabolites. Possible toxic effects need further investigation.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Applied microbiology and biotechnology 40 (1993), S. 69-76 
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract We report the optimum conditions for the degradation of oat spelt arabinoxylan and a preliminary characterisation of the inducible xylan-degrading system of the lignin-degrading white-rot fungus Phanerochaete chrysosporium. Xylanase activity was optimal at pH 5.0 and 50°C; see attached sheet the maximum reaction velocity (Vmax) of the system was 3.86 units (U) mg−1 protein with arabinoxylan as substrate and the substrate concentration giving half Vmax (S0.5) was 0.52 mg ml−1. At concentrations of arabinoxylan greater than 15 mg ml−1 excess substrate inhibition was observed. Xylose at 0.9 mm inhibited activity to the extent of 50%. Xylanase activity increased as a function of the dilution of the enzyme preparation prior to assay. It was resolved into four peaks by using a DEAE-Biogel column; the material in these peaks differed with respect to xylan solubilisation and the formation of reducing sugars. Electrofocusing gels allowed visualisation of several bands of activity corresponding to each peak. The arabinoxylan degradation system of P. chrysosporium is therefore composed of multiple components.
    Type of Medium: Electronic Resource
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  • 13
    ISSN: 1432-0509
    Keywords: Biliary tract, obstruction ; Gallstone, diagnosis ; ERCP, interventional techniques
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Therapeutic applications of endoscopic retrograde cholangiopancreatography (ERCP) have increased dramatically, and endoscopic sphincterotomy (ES) is the cornerstone of these techniques. Indications include treatment of retained biliary duct stones, papillary stenosis, benign and malignant strictures, and acute cholangitis and pancreatitis. We reviewed our recent experience to assess the spectrum of procedures done and their results. Medical records and radiographic examinations in 60 consecutive patients undergoing therapeutic ERCP were studied. Patients were placed into one of three treatment groups; Group 1, ES alone (N=21); Group 2, ES plus stone retrieval (N=15); and Group 3, ES plus stent placement (N=24). In Group 1, all of eight patients with ductal stones had spontaneous passage. In 11 patients with papillary stenosis, nine had relief of symptoms following ES. Two patients with pancreatitis improved after ES. In Group 2, all 15 patients with ductal stones had successful retrieval. In Group 3, patients were treated for biliary stricture alone (4), retained stones (7), pancreatitis (5), neoplasms (6) and papillary stenosis (2). In these 24 patient, 21 (88%) were treated successfully or had palliation of their symptoms. In our series, a wide variety of therapeutic applications of ERCP was used to manage simple and complex biliary disease. ES alone or in combination with other techniques was done in all patients. Overall, 55 (92%) of 60 interventional procedures were successful as defined by removal of stones and relief or palliation of symptoms.
    Type of Medium: Electronic Resource
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Boundary layer meteorology 59 (1992), S. 231-242 
    ISSN: 1573-1472
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract We use Monin-Obukhov similarity theory to extend the Kristensen et al. (1991) aviation gust estimation technique from the neutral to the diabatic surface layer. Example calculations demonstrate the importance of this correction. Simple stability class methods using only standard aviation surface observations are shown to be useful although less accurate and less precise than methods which make full use of Monin-Obukhov similarity results.
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    International journal of anthropology 6 (1991), S. 231-238 
    ISSN: 1824-3096
    Keywords: environment idea ; human population
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The history of environment in human terms is the history of knowing... and of not knowing... about the nature and extent of human interactions with that environment. In recent human history, those interactions (with the environment and among people) have accelerated dramatically. Human-environment relationships are complicated by that acceleration and by the resulting increases in levels of complexity. The acceleration requires a re-definition, in global terms, of what environment means and a greatly increased awareness on the part of individual people of the changes in the interaction patterns and of the resulting changes in environment, both in perception and in reality. A transcendent awareness could radically change the forms of human institutions, especially those of law and ethics. Such changes might then allow humans to temper their exchanges with and impacts on the environment.
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Statistics and computing 2 (1992), S. 161-171 
    ISSN: 1573-1375
    Keywords: Asymptotic approximations ; bootstrap calibration ; coverage accuracy ; resampling ; saddlepoint methods ; tail probability approximations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract Standard algorithms for the construction of iterated bootstrap confidence intervals are computationally very demanding, requiring nested levels of bootstrap resampling. We propose an alternative approach to constructing double bootstrap confidence intervals that involves replacing the inner level of resampling by an analytical approximation. This approximation is based on saddlepoint methods and a tail probability approximation of DiCiccio and Martin (1991). Our technique significantly reduces the computational expense of iterated bootstrap calculations. A formal algorithm for the construction of our approximate iterated bootstrap confidence intervals is presented, and some crucial practical issues arising in its implementation are discussed. Our procedure is illustrated in the case of constructing confidence intervals for ratios of means using both real and simulated data. We repeat an experiment of Schenker (1985) involving the construction of bootstrap confidence intervals for a variance and demonstrate that our technique makes feasible the construction of accurate bootstrap confidence intervals in that context. Finally, we investigate the use of our technique in a more complex setting, that of constructing confidence intervals for a correlation coefficient.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Digestive diseases and sciences 37 (1992), S. 705-708 
    ISSN: 1573-2568
    Keywords: polyethylene glycol 400 ; intestinal permeability ; small bowel permeability ; Crohn's disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An altered small bowel permeability may be implicated in the pathogenesis of Crohn's disease. Intestinal permeability, using polyethylene glycol 400 (PEG 400) as the orally ingested probe, was assessed in 45 patients with Crohn's disease (ilealN=14, ileocolonicN=9, colonicN=10, postresectionN=12), 20 first-degree relatives, and 31 controls. PEG 400 excretion was measured using a direct injection HPLC method, and results are expressed as percent of dose recovered in urine (median and range). No quantitative differences in the recovery of PEG-400 were found [Crohn's patients 21.9% (6.1–39.9), relatives 23.7% (4.9–39.9), controls 25.0% (4.5–39.7)]. In all groups, the composition of ingested and recovered PEG-400 was similar and no selective permeability to any molecular weight species was found. Disease site did not influence probe recovery [ileal 23.8% (7.7–30.6), ileocolonic 22.6% (14.4–33.8), colonic 27.8% (9.5–33.5)]. Resected patients had significantly lower PEG-400 recovery [18.8% (8.1–39.9)] than nonresected patients [23.5% (6.1–33.8%)P〈0.02]. The data suggest either that altered intestinal permeability is not a factor in Crohn's disease or that PEG-400 is not a suitable probe.
    Type of Medium: Electronic Resource
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