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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 92 (1990), S. 7302-7314 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The response of the Brusselator reaction–diffusion system to inhomogeneous perturbations is studied. The main focus of this work is on a spatial generalization of the phase resetting problem. A randomly chosen fraction p of an initially homogeneous oscillatory system is locally perturbed and driven off the limit cycle. The asymptotic local phase is monitored and averaged over local regions and realizations of the perturbation process. From this information a phase response curve can be constructed which depends both on the local stimulus amplitude and on p. The system exhibits two qualitatively different kinds of response depending on the stimulus amplitude and the phase at which the perturbation is applied. It either relaxes to a spatially homogeneous oscillatory state or develops persistent spatial patterns. The origin of this behavior is discussed.
    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 92 (1990), S. 7315-7322 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The results of a study of spatial pattern formation in a two-dimensional oscillatory reaction–diffusion system are presented. The calculations are carried out on a discrete model of the Brusselator reaction. The system responds to inhomogeneous perturbations in two different ways. For most perturbations it relaxes back to a spatially homogeneous state with a phase shift. However, special perturbations produce persistent structures which consist of spiral waves and target patterns. The nature of these spatio-temporal states is discussed.
    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. 421-434 
    ISSN: 1089-7682
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Vortex core dynamics is studied in the Brusselator both near to and far from the Hopf bifurcation line for random and pair initial conditions. Extensive simulations are carried out for a pair of counter-rotating vortices close to the Hopf bifurcation line. Provided the vortices are not so far apart that wave-front annihilation produces strong gradients between their centers, the simulation results compare favorably with theories based on the complex Ginzburg–Landau equation. Far from the Hopf line the vortex core dynamics changes character and phenomena such as periodic motion of the vortex centers arise.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 5233-5235 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Surface-energy-induced secondary or tertiary recrystallization by grains with a specific surface plane can be freely governed in thin-gauged 3% Si–Fe strips by controlling the bulk content of sulfur and annealing atmosphere. During a vacuum or hydrogen annealing process, a convex profile in segregated-sulfur concentration is formed due to evaporation or desorption of segregated sulfur as a hydrogen sulfide, corresponding to a trough in magnetic induction. High magnetic induction is obtained after the annealing treatments. Final annealing under an argon atmosphere caused a saturation in segregated-sulfur concentration with annealing time. Under this extremely high segregated sulfur, grains of high index crystal plane including {111} continued to grow, resulting in low magnetic induction. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Neural network is considered as a parameter estimation tool in plasma controls for next generation tokamak such as ITER. The neural network has been reported to be so accurate and fast for plasma equilibrium identification that it may be applied to the control of complex tokamak plasmas. For this application, the reliability of the conventional neural network needs to be improved. In this study, a new idea of double neural network is developed to achieve this. The new idea has been applied to simple plasma position identification of KSTAR tokamak for feasibility test. Characteristics of the concept show higher reliability and fault tolerance even in severe faulty conditions, which may make neural network applicable to plasma control reliably and widely in future tokamaks. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A Thomson scattering system on the Hanbit magnetic mirror device has been installed to measure the electron temperature and density of the plasma in the central cell. The configuration is based on a standard 90° scattering scheme. The optical system consists of a Q-switched Nd:YAG laser, input optics, collection optics, spectrograph optics, detectors, and a data acquisition system. Although the laser beam path is about 50 m long and the background emissions are not low, the electron temperature measurements have been made at a single point on a shot-by-shot basis, in which the stray light was considerably suppressed by using a beam dump, a viewing dump, and baffles. The measured electron temperature is about 50–70 eV in experiments for plasma production and heating by ICRF of 200-kW-rf power using a slot antenna. A description of the installed system and the experimental results are presented. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    238 Main Street, Cambridge, Massachusetts 02142, USA : Blackwell Scientific Publications
    International journal of gynecological cancer 3 (1993), S. 0 
    ISSN: 1525-1438
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Sixty-two serous and mucinous ovarian tumors, an admixture of benign, borderline and malignant neoplasms, were immunostained for proliferating cell nuclear antigen (PCNA), with the monoclonal antibody PC10. The PC10 index, the proportion of cells showing nuclear positive staining, was calculated in each case. All the tumors showed positive immunoreactivity for PCNA. There was no overlap of PC10 counts between benign, borderline and malignant serous tumors but within the mucinous group of neoplasms there was considerable overlap between the counts for borderline and malignant tumors. There was no relationship between the PC10 index and the surgical stage of the malignant neoplasms and the index could not be correlated with patient death. Staining for PCNA does not, therefore, appear to be of any prognostic value in ovarian adenocarcinomas.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1523-5378
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background.  Helicobacter pylori is a causative agent of gastritis, and H. pylori infection is thought to be correlated with iron-deficiency anemia (IDA) at puberty. The H. pylori feoB gene product, a high-affinity ferrous iron transporter, plays a central role in iron acquisition and virulence. This study was undertaken to analyze H. pylori feoB status according to clinical data, including antral gastritis with or without IDA.Methods.  Fourteen H. pylori-positive patients aged from 10 to 18 years were categorized into subgroups based on the presence or absence of IDA. Eight patients were diagnosed as having IDA; the other six showed normal hematological findings. Genomic DNA was isolated from H. pylori cultured from each gastric biopsy specimen. Five sets of primers were used for the PCR amplification of the feoB gene. Linking and sequencing of PCR products generated the feoB region, which was 1.93 kb in size. The feoB gene sequences of H. pylori J99 and 26695 were compared with the clinical strains, and the sequences of feoB regions in the IDA (+) and (–) groups were compared.Results.  Sequence analysis of the complete coding region of the feoB gene revealed 16 sites of polymorphism or mutation. Among these, three polymorphisms (E/T254A, I263V, and K511Q) were indigenous to the Korean clinical strains. Although statistically significant differences were observed at four sites (K127T, A273S/P, I438V and I441T) between IDA (+) and (–), the number of specimens was too low to assess the significance of the differences.Conclusion.  The four polymorphisms of the feoB gene observed appear to be related to the clinical phenotype of IDA, but the relation is unclear because of the small number of strains studied. Further studies are required to confirm a correlation between IDA and H. pylori infection.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of interventional cardiology 13 (2000), S. 0 
    ISSN: 1540-8183
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: With the introduction of high pressure balloon inflations and antiplatelet therapy, the incidence of stent thrombosis has been markedly reduced, but the incidence of late stent restenosis has not. A new strategy may be local drug delivery, which maintains sustained local concentration and limits systemic complications. To evaluate the efficacy of local nitric oxide (NO) donor delivery on stent thrombosis and complications, local NO donor delivery was performed in stented patients. NO donor (2.0-mg molsidomine) was delivered (1.0 mL/min 〉 10 min) using the Dispatch Catheter after predilation of target lesions in 13 patients (6 angina, 7 myocardial infarction, age 53.1 ± 11.4 years). After local NO donor delivery, Palmaz-Schutz stents were placed using standard methods. Follow-up coronary angiograms were performed 48 hours and 6 months after stenting. None of the patients had hypotensive effects, ischemic symptoms, or ECG changes during and after local NO donor delivery. APTT and CK values were unchanged at 3 and 24 hours after local NO donor delivery and stenting. Follow-up coronary angiograms at 48 hours and 6 months showed all stents patent with TIMI III flow and without intrastent thrombus. No target lesion revascularization and 100% event-free survival were observed during the 6-month clinical follow-up period. Intracoronary stenting may be performed safely and effectively by local NO donor delivery prior to stent implantation.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 87 (2004), S. 0 
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: R-curve behavior of Si3N4–BN composites and monolithic Si3N4 for comparison was investigated. Si3N4–BN composites showed a slowly rising R-curve behavior in contrast with a steep R-curve of monolithic Si3N4. BN platelets in the composites seem to decrease the crack bridging effects of rod-shaped Si3N4 grains for small cracks, but enhanced the toughness for long cracks as they increased the crack bridging scale. Therefore, fracture toughness of the composites was relatively low for the small cracks, but it increased significantly to ∼8 MPa·m1/2 when the crack grew longer than 700 μm, becoming even higher than that of the monolithic Si3N4.
    Type of Medium: Electronic Resource
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