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  • 1
    Electronic Resource
    Electronic Resource
    Numerical investigations of small-amplitude disturbances in a boundary layer with impinging shock wave at Ma=4.8 (2002)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 14 (2002), S. 2088-2101 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The stability behavior of a laminar boundary layer with shock boundary layer interaction and small amplitude disturbances is investigated by linear stability theory and direct numerical simulation. By a complex interaction of several physical properties, the impinging shock wave locally influences stability behavior of the boundary layer, dependent on its shock strength, applied disturbance frequency, and disturbance propagation angle with respect to the flow direction (obliqueness angle). Due to the displacement of the boundary layer near shock impingement and the according Reynolds number effect in this area, the boundary layer is locally destabilized. The displacement of the boundary layer also produces an increase of the thickness of local regions of relative supersonic speed, which promotes second mode instability. For the results obtained by direct numerical simulation nonparallel effects could be identified and quantified. Taking these nonparallel effects into account, linear stability theory is able to represent the stability behavior of wall distant disturbance amplitude maxima having small obliqueness angles for the cases investigated here. For larger obliqueness angles and disturbance amplitudes at or close to the wall the agreement between linear stability theory and direct numerical simulation declines considerably. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1480265
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of H. pylori on the Expression of TRAIL, FasL and their Receptor Subtypes in Human Gastric Epithelial Cells and their Role in Apoptosis (2004)
    Oxford, UK : Blackwell Science Ltd
    Helicobacter 9 (2004), S. 0 
    Details
    ISSN: 1523-5378
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background and Aims.  In the human stomach expression of TNF-related apoptosis inducing ligand (TRAIL) and its receptors and the modulatory role of Helicobacter pylori are not well described. Therefore, we investigated the effect of H. pylori on the expression of TRAIL, FasL and their receptors (TRAIL-R1-R4, Fas) in gastric epithelial cells and examined their role in apoptosis.Materials and Methods.  mRNA and protein expression of TRAIL, FasL and their receptors were analyzed in human gastric epithelial cells using RT-PCR, Western blot, and immunohistochemistry. Gastric epithelial cells were incubated with FasL, TRAIL and/or H. pylori, and effects on expression, cell viability and epithelial apoptosis were monitored. Apoptosis was analyzed by histone ELISA, DAPI staining and immunohistochemistry.Results.  TRAIL, FasL and their receptor subtypes were expressed in human gastric mucosa, gastric epithelial cell primary cultures and gastric cancer cells. TRAIL, FasL and H. pylori caused a time- and concentration-dependent induction of DNA fragmentation in gastric cancer cells with synergistic effects. In addition, H. pylori caused a selective up-regulation of TRAIL, TRAIL-R1 and Fas mRNA and protein expression in gastric cancer cells.Conclusions.  Next to FasL and Fas, TRAIL and all of its receptor subtypes are expressed in the human stomach and differentially modulated by H. pylori. TRAIL, FasL and H. pylori show complex interaction mediating apoptosis in human gastric epithelial cells. These findings might be important for the understanding of gastric epithelial cell kinetics in patients with H. pylori infection. 

    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1083-4389.2004.00269.x
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  • 3
    Electronic Resource
    Electronic Resource
    Experimental Helicobacter pylori Infection Induces Antral-Predominant, Chronic Active Gastritis in Hispid Cotton Rats (Sigmodon hispidus) (2005)
    Oxford, UK : Blackwell Science Ltd
    Helicobacter 10 (2005), S. 0 
    Details
    ISSN: 1523-5378
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background.  The hispid cotton rat has proven to be an excellent animal model for a variety of human infectious disease agents. This study was performed to evaluate the use of the cotton rat as a model of Helicobacter pylori infection.Materials and methods.  Thirty-eight inbred cotton rats were orogastrically inoculated with a human strain of H. pylori. Twenty-eight control cotton rats were dosed with vehicle only. Animals were sacrificed at 2, 4, 12, 26, or 38 weeks after inoculation for bacterial and histologic and immunologic examinations.Results.  Helicobacter pylori was cultured from the glandular stomach of 89% of the infected cotton rats. The level of colonization was consistently high (approximately 104−6 colony-forming units/g tissue). Histologically, the spiral bacteria were demonstrated on the epithelial surface and in the foveolae of the gastric mucosa with highest numbers in the antrum. H. pylori infection was associated with antral-predominant, chronic active gastritis which progressively increased in severity over time. By week 26 of infection, moderate antral gastritis had developed with frequent involvement of the submucosa and formation of lymphocytic aggregates. Splenic T cells from infected cotton rats expressed mRNAs for interferon-γ, interleukin-4, interleukin-6, and interleukin-10 following in vitro stimulation with H. pylori. Serum levels of H. pylori-specific immunoglobulin G were significantly elevated after 12 weeks of infection.Conclusions.  The H. pylori-infected cotton rat represents a novel animal model that should prove useful for studies of H. pylori-induced chronic active gastritis and factors affecting gastric colonization by this pathogen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1523-5378.2005.00320.x
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  • 4
    Electronic Resource
    Electronic Resource
    Zur Isotopieverschiebung im Cul-Spektrum (1955)
    Springer
    The European physical journal 141 (1955), S. 122-145 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Zusammenfassung Die Isotopieverschiebung (Is.V.) im Cu I-Spektrum wurde mit den massenspektrographisch getrennten Isotopen63Cu und65Cu untersucht. Die in den beiden Resonanzlinien 3d 10 4s(2 S 1/2)-3d 10 4p (2 P°1/2,3/2) und in 12 Linien des Komplexspektrums 3d 9 4s 2 (m 2 D 3/2,5/2)-3d 9 4s 4p beobachteten Is.V. von rund +20 · 10−3 cm−1 können gemeinsam mit den großen in vier Interkombinationslinienm 2 D 3/2,5/2-4p 2 P°1/2,3/2 (bzw. 5p 2P°) gemessenen Is.V. von +74 · 10−3 cm−1 und der bei den beiden Interkombinationen 3d 10 4s (2S1/2)-3d 9 4s 4p (z4 P°1/2, 3/2) beobachteten Vorzeichenumkehr der Is.V. (−28 · 10−3 cm−1) in ein einheitliches Schema eingeordnet werden, das die in den Linien beobachteten Is.V. auf die an den übergängen beteiligten Terme zurückführt. Es ergibt sich dabei ein beträchtlicher Unterschied in den Is.V. der zu den Elektronenkonfigurationen 3d 10 nl gehörenden Terme gegenüber denen der Terme 3d 9 4s 2 bzw. 3d 9 4s 4p. Diese Erscheinung kann auf der Grundlage von Kopplungseffekten der Kernmitbewegung gedeutet werden. Theoretische überlegungen zeigen, daß die Kopplungseffekte gewisser Terme vorzeichendefinit sind. Damit ergibt sich bei zweckmäßiger Normierung der Is.V. in den Termen, daß die Kopplungseffekte in den Termen mit dem Elektronenrumpf 3d 10 wesentlich größer sind als in denen mit dem Rumpf 3d 9. Auf Grund der Theorie der Kopplungseffekte ist es möglich, diesen Unterschied dem in diesen Termen fehlenden 3d-Elektron, im besonderen den dadurch teilweise fortfallenden (3d 2p) - und (3d 3p)-Kopplungen zuzuschreiben.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01327293
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  • 5
    Electronic Resource
    Electronic Resource
    Differential mRNA decay within the transfer operon of plasmid R1: identification and analysis of an intracistronic mRNA stabilizer (1996)
    Springer
    Molecular genetics and genomics 250 (1996), S. 466-476 
    Details
    ISSN: 1617-4623
    Keywords: Key words Gene expression ; mRNA processing ; Differential mRNA stability ; traA mRNA ; Plasmid R1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Processing of the transfer operon mRNA of the conjugative resistance plasmid R1-19 results in the accumulation of stable traA mRNAs. The stable traA transcripts found in vivo have identical 3′ ends within downstream traL sequences, but vary at their 5′ ends. The 3′ ends determined coincide with the 3′ base of a predicted large clover-leaf-like RNA secondary structure. Here we demonstrate that this putative RNA structure, although part of a coding sequence, stabilizes the upstream traA mRNA very efficiently. We also show that the 3′ ends of the stable mRNAs are formed posttranscriptionally and not by transcription termination. Half-life determinations reveal the same half-lives of 13±2 min for the traA mRNAs transcribed from hybrid lac-traAL-cat test plasmids, the R1-19 plasmid, and the F plasmid. Protein expression experiments demonstrate that the processed stable traA mRNA is translationally active. Partial deletions of sequences corresponding to the predicted secondary structure within the traL coding region drastically reduce the chemical and functional half-life of the traA mRNA. The results presented here unambiguously demonstrate that the proposed secondary structure acts as an efficient intracistronic mRNA stabilizer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02174035
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  • 6
    Electronic Resource
    Electronic Resource
    Helicobacter pylori Reduces Intracellular Glutathione in Gastric Epithelial Cells (2000)
    Springer
    Digestive diseases and sciences 45 (2000), S. 1769-1773 
    Details
    ISSN: 1573-2568
    Keywords: H. pylori ; gastric cells ; glutathione ; reactive oxygen species
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Helicobacter pylori infection has been associated with stimulation of gastric mucosal reactive oxygen species (ROS) production, and it was postulated that ROS production is due to neutrophil infiltration and activation. The aim of this study was to investigate the direct effect of H. pylori on ROS formation in gastric epithelial cells in vitro. The human gastric cancer cell line HM02 was incubated with H. pylori for 24 hr, and the effects on cell number and the intracellular radical scavenger reduced glutathione (GSH) were assessed. H. pylori caused a concentration-dependent reduction of cellular GSH concentrations over a broad bacteria-to-cell ratio (1.4–42) in the absence of cell necrosis. The radical scavengers MnTBAP (a cell permeable superoxide dismutase) and ebselen provided protection against H. pylori-induced decrease in cellular GSH concentrations. We conclude that H. pylori directly decreases cellular GSH concentrations in gastric epithelial cells. We suggest that this effect is caused by the release of ROS by H. pylori.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005530227603
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  • 7
    Book
    Book
    High performance computing in science and engineering, Munich 2004 : transactions of the Second Joint HLRB and KONWIHR Status and Result Workshop, March 2 - 3, 2004, Technical University of Munich, and Leibniz-Rechenzentrum Munich, Germany ; with 42 tables (2005)
    Berlin [u.a.] :Springer,
    Details
    Title: High performance computing in science and engineering, Munich 2004 : transactions of the Second Joint HLRB and KONWIHR Status and Result Workshop, March 2 - 3, 2004, Technical University of Munich, and Leibniz-Rechenzentrum Munich, Germany ; with 42 tables
    Contributer: Wagner, Siegfried , Joint HLRB and KONWIHR Status and Result Workshop 〈2, 2004, München〉
    Publisher: Berlin [u.a.] :Springer,
    Year of publication: 2005
    Pages: XIII,484 S. : , Ill., graph. Darst. ; , 235 mm x 155 mm
    ISBN: 3-540-44326-6
    Type of Medium: Book
    Language: English
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