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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 102 (1995), S. 8175-8184 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Submonolayers of gold were evaporated onto a Pt(110) surface in order to study the influence of surface modification on the formation of spatiotemporal concentration patterns during catalytic oxidation of carbon monoxide as imaged by means of photoemission electron microscopy (PEEM). Already the presence of 0.05 monolayers of uniformly distributed Au atoms affects markedly the kinetic parameters and thereby the properties of spatiotemporal patterns. The excitable regime is reached at lower CO pressures than with bare Pt(110), the width of the oxygen waves and the wavelength of spiral patterns decrease, the velocity of front propagation is reduced, and the density of nucleation centers for waves increases. The observed effects can be rationalized on the basis of the well-established underlying mechanism in terms of modification of the sticking coefficients for oxygen and carbon monoxide and of the diffusion coefficient for adsorbed CO. Additional effects such as penetration of waves into a monostable region, refraction, etc., come into play if waves pass the border between surface areas with differing chemical properties. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 53 (1997), S. 216-217 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 169-170 (June 1999), p. 67-70 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Chester : International Union of Crystallography (IUCr)
    Journal of synchrotron radiation 3 (1996), S. 160-162 
    ISSN: 1600-5775
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: A CdTe solid-state detector was applied to the measurement of polarization-dependent total-reflection fluorescence XAFS spectra. The data revealed that the detector has good sensitivity, and this, together with its compact size, make it appropriate for in-situ measurements and removal of X-ray Bragg diffraction. The detector efficiently recorded the high-energy K-edge XAFS spectra for molybdenum oxides supported on TiO2 (110).
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Chester : International Union of Crystallography (IUCr)
    Journal of synchrotron radiation 6 (1999), S. 439-441 
    ISSN: 1600-5775
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1420-908X
    Keywords: Key words: Hypersensitivity — Allergic rhinitis — Guinea pig — Cyclosporin A — Glucocorticosteroid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Objective and Design: In an attempt to study the pathogenesis of mucosal hypersensitivity in allergic rhinitis, we investigated the suppressive effects of cyclosporin A (CyA) and glucocorticosteroids on ovalbumin (OA)-induced hypersensitivity to topical histamine challenge.¶Materials: Actively sensitized Dunkin-Hartley guinea pigs.¶Treatment: OA and alum were applied to guinea pigs intraperitoneally 3 times at two-week intervals. After general sensitization, OA inhalation was performed every day for 6 days as topical sensitization. Before inhalation, treatment with CyA (50 mg/kg, p.o.), glucocorticosteroids (beclomethasone propionate (1.0 mg/kg, i.p.), fluticasone propionate (FP, 0.5 mg/kg, i.p.)) or vehicle were performed, and the sensitivity to histamine was measured before and after the inhalation. Moreover, in actively (general and topical) sensitized guinea pigs, FP (0.5 mg/kg, i.p.) was applied every day for 5 days and histamine sensitivity was evaluated before and after the application.¶Results: We found that histamine sensitivity was significantly increased by nasal antigen challenge in this guinea pig model, and that the occurrence of histamine hypersensitivity was inhibited by the pretreatment with CyA and glucocorticosteroids. Although multiple administration of FP gradually reduced the histamine hypersensitivity according to the period of administration, it did not significantly alter the histamine hypersensitivity after the occurrence of hypersensitivity.¶Conclusion: It is concluded that CyA and glucocorticosteroids suppress antigen-induced histamine hypersensitivity in a guinea pig model of allergic rhinitis.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1420-908X
    Keywords: Key words: Guinea pig — NK1 receptor antagonist — Substance P — Plasma exudation — Nasal allergy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract.   Objective: To study the inhibitory effects of two NK1 receptor antagonists on substance P (SP) and antigen-induced increase of nasal vascular permeability in ovalbumen (OA)-sensitized guinea pigs. ¶Material: Male Dunkin-Hartley guinea pigs. ¶Treatment: SP (100 〈mu〉;mol/l), FK224 (1–10 〈mu〉 mol/kg) and FK888 (0.2– 2 〈mu〉mol/kg). ¶Methods: The in vivo model of nasal microvascular leakage was used for nasal allergic challenge in ovalbumin (OA)-sensitized guinea pigs, or nasal stimulation with substance P (SP) in non-sensitized animals. Nasal microvascular leakage was measured by the accumulation of Evans Blue dye after intravenous injection. ¶Results: Following nasal stimulation with SP 100 〈mu〉M, the concentration of dye in the nasal lavage fluid rapidly increased. NK1 receptor antagonists FK224 (10 〈mu〉mol/kg i.v.) and FK888 (2 〈mu〉mol/kg i.v.) inhibited SP-induced microvascular leakage. In OA-sensitized guinea pigs, exudation of dye into nasal lavage fluid was observed soon after topical antigenic stimulation and continued for over 60 min. Both NK1 receptor antagonists inhibited the immediate phase of the antigen-induced microvascular leakage. ¶Conclusions: We conclude that the immediate change of vascular permeability during the nasal allergic response is mediated by activation of the NK1 receptor in the guinea-pig.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1420-908X
    Keywords: Key words: Leukotriene — Allergic rhinitis — Guinea pig models — Total airway resistance — Nasal symptoms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Objective and Design: To define the role of leukotriene (LT) in allergic rhinitis, we examined the effects of a cysteinyl (Cys) LT antagonist (ONO-1078, pranlukast).¶Material: Actively sensitized Dunkin-Hartley guinea pigs.¶Treatment: ONO-1078 (pranlukast), 3–100 mg/kg p.o. l h before antigen challenge.¶Methods: Nasal symptoms (sneezing, nasal scratches), changes of total airway resistance (TAR by plethysmography) and eosinophil infiltration into the nasal mucosa were determined following topical antigen (OA) challenge. Dunnet's test (TAR and symptoms) and the Mann-Whitney U-test (eosinophils) were applied.¶Results: Control animals showed bi-phasic nasal responses, peaking 10 min and 240 min after the topical antigen challenge, respectively. While the early-phase response was characterized by nasal symptoms of sneezing and scratching accompanied by the increase in TAR, the late-phase was characterized by an increase in TAR accompanied by eosinophil infiltration into nasal mucosa. The nasal symptoms (sneezing and scratching) were not inhibited by pretreatment with ONO-1078 at doses up to 100 mg/kg (p.o., n = 15). Although early peak responses of TAR were not affected with even the highest dose (30 mg/kg, p.o., n = 6), late-phase TAR peak response (control: 174.8 ± 8.2%, n = 6) were significantly inhibited by 10 mg/kg (142.7 ± 15.8%; p 〈 0.05, n = 6) and 30 mg/kg (118.0 ± 6.6%; p 〈 0.01, n = 6) of ONO-1078 (p.o.). In addition, the eosinophil infiltration induced by the antigen was not inhibited by ONO-1078 (30 and 100 mg/kg, p.o., n = 6).¶Conclusions: Our results suggest that Cys LT may play an important role in the late-phase increase in TAR in the guinea pig model of allergic rhinitis.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1572-879X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract X-ray absorption near-edge structure (XANES) spectra at the Pt L3-edge for Pt particles supported on SiO2 under CO adsorption and CO+H2 coadsorption were recorded to analyze the amount of adsorbed hydrogen in the coadsorbed state on the Pt particles. Adsorbed CO on the Pt particles revealed a new peak at 6 eV above the Pt L3-edge in the difference spectra before and after CO adsorption in the coverage range 0.10-0.51. Subsequent adsorption of hydrogen at various coverages on the CO-preadsorbed Pt particles broadened and shifted the peak to the higher energy side. The peak was deconvoluted to two components due to adsorbed hydrogen and CO by a linear least-squares fitting technique. It was found that the fitting coefficient with respect to adsorbed hydrogen was proportional to the amount of adsorbed hydrogen. The XANES difference spectra provide a quantitative analysis method for adsorbed hydrogen on supported Pt particles in the presence of coadsorbates like CO.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 255 (1998), S. 18-21 
    ISSN: 1434-4726
    Keywords: Key words Parotid gland ; Solitary fibrous tumor ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Solitary fibrous tumors (SFT) arise in the pleura and less commonly in extrapleural sites. Head and neck regions have included the nose and paranasal sinuses, soft palate, epiglottis, thyroid, parotid and submandibular glands, as well as the infratemporal fossa and parapharyngeal space. We report a case of SFT arising from the parotid gland and extending to the parapharyngeal space. To our knowledge, this is the fourth case of SFT originating from the parotid gland and is the largest of its kind among the extrapleural lesions described. The characteristics revealed by computed tomography and magnetic resonance imaging are presented.
    Type of Medium: Electronic Resource
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