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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Pure and applied geophysics 156 (1999), S. 631-649 
    ISSN: 1420-9136
    Keywords: Key Words: H/V ratio, spectral ratio, site response, microtremor, resonant frequency, amplification.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —The applicability of the single-station H/V method, based on the spectral ratio between the horizontal and the vertical components of strong ground motions, is examined for site-response estimation using the high quality data from the 1994 Northridge earthquake sequence. Instead of using Rayleigh-wave data from microtremors, the large amplitude-wave part of the S-wave data is used and based on the 1994 Northridge mainshock and aftershock recordings. We have found that upon averaging over a number of recordings for a given station, the station site responses, derived both from the single-station H/V ratio and from the standard spectral ratio (with respect to a reference rock-site station) are sufficiently close for practical purposes. We therefore conclude that the H/V ratio can reasonably predict the resonant frequency and the amplification level of a site response, especially for sites in the neighborhood of the epicenters. In the absence of a reference rock-site station, the H/V ratio provides a practical alternative to the standard site-response estimation.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 200 (1999), S. 153-160 
    ISSN: 1432-0568
    Keywords: Key words Bronchi ; Sensory axons ; Neuropeptides ; Immunocytochemistry ; Plasma extravasation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The vagal nerve trunk in the mediastinum of mammals divides into two main branches, the thoracic vagus nerve and the recurrent laryngeal nerve, in which the sensory nerve axons are largely involved in neurogenic inflammation in the tracheobronchial airways. A previous study demonstrated that cutting the right-side thoracic vagus nerve but not the recurrent laryngeal nerve inhibited capsaicin-induced neurogenic inflammation in the right bronchial tree of the rat. The effect of left thoracic vagus nerve section is still not known. The main purpose of the present study was to investigate the effect of sectioning the right or left thoracic vagus nerve on the innervation density of substance P-immunoreactive axons in bilateral bronchial trees. Following nerve degeneration, the whole mounts of airway tissues were processed with substance P immunohistochemistry. Denervation of either thoracic vagus nerve reduced the innervation density of axons by 38–71% in different parts of the ipsilateral bronchial tree. The effect of right recurrent laryngeal nerve section was less specific; the innervation density was reduced by 21–39% in the trachea and bronchi of both sides. Capsaicin-induced neurogenic plasma leakage was decreased in the left mainstem bronchus and lobar bronchi after left thoracic vagus nerve section. It is concluded that the thoracic vagus nerve largely contributed to the sensory innervation in the ipsilateral bronchial airways and modulated their functions.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 143 (1995), S. 29-35 
    ISSN: 1432-1424
    Keywords: Na+-K+-ATPase ; Electrophysiology ; K+ channel ; Tetraethylammonium ; Conductance regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Using the two-microelectrode voltage clamp technique in Xenopus laevis oocytes, we estimated Na+-K+-ATPase activity from the dihydroouabain-sensitive current (I DHO) in the presence of increasing concentrations of tetraethylammonium (TEA+; 0, 5, 10, 20, 40 mm), a well-known blocker of K+ channels. The effects of TEA+ on the total oocyte currents could be separated into two distinct parts: generation of a nonsaturating inward current increasing with negative membrane potentials (V M) and a saturable inhibitory component affecting an outward current easily detectable at positive V M. The nonsaturating component appears to be a barium-sensitive electrodiffusion of TEA+ which can be described by the Goldman-Hodgkin-Katz equation, while the saturating component is consistent with the expected blocking effect of TEA+ on K+ channels. Interestingly, this latter component disappears when the Na+-K+-ATPase is inhibited by 10 μm DHO. Conversely, TEA+ inhibits a component of I DHO with a k d of 25±4 mm at +50 mV. As the TEA+-sensitive current present in I DHO reversed at −75 mV, we hypothesized that it could come from an inhibition of K+ channels whose activity varies in parallel with the Na+-K+-ATPase activity. Supporting this hypothesis, the inward portion of this TEA+-sensitive current can be completely abolished by the addition of 1 mm Ba2+ to the bath. This study suggests that, in X. laevis oocytes, a close link exists between the Na-K-ATPase activity and TEA+-sensitive K+ currents and indicates that, in the absence of effective K+ channel inhibitors, I DHO does not exclusively represent the Na+-K+-ATPase-generated current.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Experiments in fluids 25 (1998), S. 283-297 
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  The Reynolds-averaged flow for a solid/free-surface juncture boundary layer and wake is documented. The three mean-velocity components and five of the Reynolds stresses are measured for a surface-piercing flat plate in a towing tank using a laser-Doppler velocimeter system for both boundary-layer and wake planes in regions close to the free surface. The experimental method is described, including the foil-plate model, laser-Doppler velocimeter system, conditions, and uncertainty analysis. The underlying flow data is in excellent agreement with benchmark data. Inner (near the plate and wake centerplane and below the free surface) and outer (near the free surface) regions of high streamwise vorticity of opposite sign are observed, which transport, respectively, high mean velocity and low turbulence from the outer to the inner and low mean velocity and high turbulence from the inner to the outer portions of the boundary layer and wake. For the wake, the inner region of vorticity is relatively weak. The physical mechanism for the streamwise vorticity is analyzed with regard to the Reynolds-averaged streamwise vorticity equation. The anisotropy of the crossplane normal Reynolds stresses closely correlates with the vorticity and, additionally, indicates similarity, i.e., its nature is such that it only depends on the proximity to the plate and free surface boundaries or wake centerplane symmetry plane. Free-surface effects on the Reynolds stresses are analyzed with regard to the behavior close to the free surface of the turbulent kinetic energy and the normal components of the anisotropy tensor and the anisotropy invariants. Close to the free surface, the turbulent kinetic energy is nearly constant and increases for the inner and outer portions, respectively, of the boundary layer and wake and the normal components of the anisotropy tensor and the anisotropy invariants roughly correspond to the limiting values for two-component turbulence. The similarities and differences between the present results and analysis with those from related studies are discussed. The data and analysis should have practical application with regard to the development of turbulence models for computational fluid dynamics methods for the Reynolds-averaged Navier–Stokes equations.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0738
    Keywords: Key words N-nitroso-N-(3-keto-1 ; 2-butanediol)-3′-nitrotyramine ; Unschedule DNA synthesis ; Genotoxicity ; Initiating agent
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract   N-Nitroso-N-(3-keto-1,2-butanediol)-3′-nitrotyramine (NO-NTA) is a product of a model browning system in the presence of sodium nitrite. In this study, the chemical structure is confirmed by spectral studies, including UV, mass spectrometry, nuclear magnetic resonance and infrared spectroscopy. NO-NTA is strongly genotoxic to the rat hepatocyte and is moderately cytotoxic to mouse C3H10T1/2 cells. Results obtained in this study indicate that NO-NTA inflicted DNA damage through the formation of a DNA adduct. In addition, C3H10T1/2 cells were treated with NO-NTA and, following addition of 12-O-tetradecanoylphorbol-13-acetate (TPA) as promotor, the increase of transformed foci indicated that NO-NTA could possibly be an inhibitor of TPA tumor promotion. A transformed cell line from NO-NTA initiated and TPA promoted foci increased saturation density and growth ability in soft agar reactive to the control line. These results suggest that the formation of a genotoxic agent of nitroso-derivatives may take place in a nitrite-containing food system during processing and cooking.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 64 (1995), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: An alteration in signal transduction systems in Alzheimer's disease (AD) would likely be of pathophysiological significance, because these processes control normal brain functions. Previously, a diminished β-adrenergic-mediated cyclic AMP response was found in cultured fibroblasts from AD patients. Because cross-talk between the phosphoinositide and cyclic AMP pathways exists, the phosphoinositide cascade was studied under conditions that were similar to those for studying the cyclic AMP response. Cells from AD patients and age-matched controls responded to bradykinin (BK) and released inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] in a time- and dose-dependent manner. The level of Ins(1,4,5)P3 increased rapidly and transiently in response to BK, peaked at 5 s, but still remained 116–132% above the basal level by 30 s. Although the temporal patterns were similar in both groups, the Ins(1,4,5)P3 concentrations in AD fibroblasts were 73 and 89% above levels in the age-matched controls at 5 and 10 s, respectively. Prostaglandin E1 also increased Ins(1,4,5)P3 formation, but this response was not different between the two groups. Although KD (affinity) values for the BK receptor were similar in both control and AD cells, the number of BK receptors (Bmax) was significantly elevated in AD fibroblasts (186.8 ± 0.8 fmol/mg of protein) as compared with control fibroblasts (57.2 ± 15.3 fmol/mg of protein). These results indicate that the elevated Ins(1,4,5)P3 production in response to BK in AD fibroblasts is positively correlated with an increase in the receptor numbers.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 6060-6062 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Structure of 180° one-dimensional domain wall (DW) in a uniaxial ferromagnet in the presence of an external magnetic field arbitrarily oriented with respect to the DW has been investigated. Solutions of the system of equations which describe the behavior of the magnetic moment inside the DW in the case when the magnetization azimuthal angle is dependent upon the coordinate normal to the DW have been obtained and influence of magnetic field on the structure of the DW analyzed. Dependences of the effective widths of the distributions of both the polar and azimuthal angles of magnetization across the DW proper have been obtained. The effective width due to the azimuthal angle variation along the DW normal was found to increase with increasing transverse field. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Anaesthesia 50 (1995), S. 0 
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A prospective study was conducted to see the effect on spinal anaesthesia of the dilution of isobaric 0.5% bupivacaine with cerebrospinal fluid. Sixty patients were randomly allocated to three groups. In group 1, patients received 3 ml isobaric 0.5% bupivacaine intrathecally without aspirating cerebrospinal fluid. In groups 2 and 3, cerebrospinal fluid 1 ml and 2 ml was aspirated respectively and mixed with 3 ml isobaric 0.5% bupivacaine. A total volume of 4 ml in group 2 and 5 ml in group 3 was administered. Thus, the volume of cerebrospinal fluid remained unchanged. Pinprick analgesia and motor block was evaluated from induction until recovery. No differences in onset time, duration and‘two segments regression’ were noticed. The only statistical difference was the time to reach complete motor block, which was shorter in group I as compared to groups 2 and 3 (6.9 SD 1.4 min versus 11.3 SD 3.0 and 13.5 SD 3.9 min respectively). The mean value of maximum decrease in systolic blood pressure was small, being less than 15% of the pre-operative value for each group. In conclusion, the effect of diluting isobaric 0.5% bupivacaine with cerebrospinal fluid, 1 ml and 2 ml, is minimal and it is an unnecessary procedure with limited clinical effect.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 4430-4432 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An improved model is proposed to deal with the magnetic bilayer systems taking into account the contribution of the anisotropy energy and biquadratic exchange coupling to elaborate on the evolution of the magnetoresistance (MR) ratio and magnetization process. The results indicate that the characteristic behavior of the MR ratio depends distinctly on both the biquadratic coupling constant and the layer thickness. The profile of the MR ratio was found to vary from an inverted bell shape to a concave pyramid with increasing biquadratic coupling strength, and decays sharply with the layer thickness. This model calculation helps us to provide a venue for further understanding the MR or giant magnetoresistance behavior of the magnetic multilayer system. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 1406-1408 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Tensile stress induced by backside CoSi2 films on a silicon substrate has been found to enhance the growth of C54–TiSi2 on (001)Si. In contrast, compressive stress induced by backside oxide films on the silicon substrate was found to retard significantly the growth of C54–TiSi2 on (001)Si. For Ti on stressed (001)Si after rapid thermal annealing at 800 °C for 30 s, the thickness of the C54– TiSi2 films was found to increase and decrease with the tensile and compressive stress levels, respectively. The retarded growth is attributed to the hindrance of the migration of Si through the Ti/Si interface by the compressive stress. On the other hand, the presence of tensile stress promotes the Si diffusion to facilitate the formation of Ti silicide thin films. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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