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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 351-360 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We describe an open one-dimensional reaction–diffusion system, the Couette reactor, which provides a permanent feed of fresh reactants and simultaneously preserves the diffusion process. Different compositions of variants of chlorite–iodide reactions are fed at both ends, but there is no net axial mass flux in the reactor. The effective diffusion coefficient is the same for all chemical species, and can easily be varied from 10−2 to 1 cm2/s, permitting large size reaction–diffusion structures. Spatial bistability was obtained with the minimal chlorite–iodide reaction in symmetric feed conditions. A larger variety of patterns was observed with the chlorite–iodide–malonic acid reaction and asymmetric feed conditions: a single steady chemical front, two steady fronts, three steady fronts, a single oscillating front, two oscillating fronts, three oscillating fronts, simple colliding fronts, and a bursting pattern. The patterns were studied as a function of several parameters to determine the sequences of bifurcations. Our observations demonstrate the existence of steady chemical patterns other than Turing patterns.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 96 (1992), S. 6126-6131 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have conducted experiments and simulations of the spatial variation of a short-lived intermediate species (triiodide) in the autocatalytic oxidation of arsenite by iodate in a reactor that is essentially one dimensional—the Couette reactor. (This reactor consists of two concentric cylinders with the inner one rotating and the outer one at rest; reagents are continuously fed and removed at each end in such a way that there is no net axial flux and there are opposing arsenite and iodate gradients.) The predictions of a one-dimensional reaction–diffusion model, which has no adjustable parameters, are in good qualitative (and, in some cases, quantitative) agreement with experiments. Thus, the Couette reactor, which is used to deliberately create spatial inhomogeneities, can be exploited to enhance the recovery of short-lived intermediate species relative to that which can be obtained with either a batch or continuous-flow stirred-tank reactor.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Chaos 1 (1991), S. 411-420 
    ISSN: 1089-7682
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Experiments have been conducted on Turing-type chemical spatial patterns and their variants in a quasi-two-dimensional open spatial reactor with a chlorite–iodide–malonic acid reaction. A variety of stationary spatial structures−hexagons, stripes, and mixed states−were observed, and transitions to these states were studied. For conditions beyond those corresponding to the emergence of patterns, a transition was observed from stationary spatial patterns to chemical turbulence, which is marked by a continuous motion of the pattern within a domain and of the grain boundaries between domains. The transition to chemical turbulence was analyzed by measuring the correlation length, the average pattern speed, and the total length of the domain boundaries. The emergence of chemical turbulence is accompanied by a large increase in the defects in the pattern, which suggests that this is an example of defect-mediated turbulence.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 96 (1992), S. 6773-6776 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 91 (1987), S. 6040-6042 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 15 (2001), S. 0 
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Short-term proton pump inhibitor-based triple therapies for the eradication of Helicobacter pylori are used widely. The eradication rates vary greatly from country to country and from region to region.〈section xml:id="abs1-2"〉〈title type="main"〉Aim:To assess the efficacy at eradicating H. pylori of 1-week regimens containing three medications: omeprazole (O) or colloidal bismuth subcitrate (B), furazolidone (F) or metronidazole (M), and amoxicillin (A) or clarithromycin (C).〈section xml:id="abs1-3"〉〈title type="main"〉Methods:A multicentre study involving 20 hospitals in different regions of China. A total of 892 patients with H. pylori-positive non-ulcer dyspepsia or healed duodenal ulcer confirmed by endoscopy were recruited to receive, randomly, one of four regimens: OMC, OFC, OFA, and BFC, b.d. for 7 days. 13C-urea breath test was performed 4–8 weeks after completion of treatment.〈section xml:id="abs1-4"〉〈title type="main"〉Results:The eradication rates with per protocol/intention-to-treat analyses were: OMC (n=217/219) 66%/65%; OFC (n=227/229) 69%/69%; OFA (n=223/225) 87%/86%; and BFC (n=214/219) 80%/78%. The eradication rate (per protocol analysis) in duodenal ulcer (79%) was higher than that in non-ulcer dyspepsia (73%, P=0.033). Patient compliance was good. The adverse events of the four regimens were mild, and mainly gastrointestinal.〈section xml:id="abs1-5"〉〈title type="main"〉Conclusions:The omeprazole, furazolidine and amoxicillin regimen achieves a high H. pylori eradication rate in different geographical regions of China.
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  • 7
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 379 (1996), S. 143-146 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The study of spiral patterns in the Belousov-Zhabotinsky (BZ) reaction has generated fruitful results4"10. However, except in recent years11"13, all experiments have been conducted in closed systems where the ageing of the chemical solution hinders the study of a steady nonequilibrium state. As a ...
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 183 (1992), S. 62-69 
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Physics Letters A 134 (1989), S. 282-286 
    ISSN: 0375-9601
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Physica A: Statistical Mechanics and its Applications 188 (1992), S. 17-25 
    ISSN: 0378-4371
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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