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  • 1
    Electronic Resource
    Electronic Resource
    Grain-boundary slit propagation in an electric field (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 6670-6676 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Advancement of a fine slit along a planar grain boundary in an electric field E0, applied parallel to the slit, is investigated by considering electromigration along both the grain boundary and the slit surface. Electrically induced flux in the grain boundary Igb (+ toward the slit tip) and both electrically and curvature-induced fluxes on the slit surfaces are considered assuming 2Is〉Igb, where Is is the flux (+ away from the slit tip) on each of the parallel slit surfaces far removed from the tip. Steady-state solutions of the transport equations are classified according to the value of a parameter β=tan−1 (2Is/Igb) which, under reasonable assumptions, depends on material parameters only. For 5π/4≥β≥β2, unique steady-state solutions exist; for β2〉β〉β1, multiple steady-state solutions occur; below β1≥π/4, no steady-state solution is possible. Since β1〈π/2, Igb〉0 (flux exiting the grain boundary into the slit) for all cases in which no steady-state solution is possible. In the case of multiple solutions, those corresponding to smallest width (and hence largest velocity) are determined. For all steady-state solutions, slit width and tip velocity scale as E−1/20 and E3/20, respectively. Results also apply to the propagation of a slit within a grain or along a passivation layer. Generally, tip velocities can approach 1 nm/s (3.6 μm/h), thereby representing a likely failure mechanism in fine-line (near bamboo structure) interconnects. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363792
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  • 2
    Electronic Resource
    Electronic Resource
    Extensions of thermal grooving for arbitrary grain-boundary flux (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 3833-3838 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Groove profiles are computed under isotropic conditions for the intersection of a periodic array of grain boundaries with an external surface, assuming that grain boundary flux I is directed to (I(approximately-greater-than)0) or away from (I〈0) the surface. When I=0, the surface assumes an equilibrium (time-independent) profile. For I≠0, in a range bounded by upper and lower limits that depend on geometry and material parameters, a global steady-state develops in which the entire surface advances (I(approximately-greater-than)0) or recedes (I〈0) from its original position at constant velocity. Beyond these limits, the surface near the groove roots becomes diffusively detached from the remaining surface. A rapidly growing ridge (I(approximately-greater-than)0) or slit (I〈0) then develops along each grain boundary, whose tip ultimately translates at constant velocity in a local steady state, leaving the remaining surface behind. These velocity regimes govern the ultimate stability of polycrystalline materials subjected to large electric (electromigration) or stress (creep) fields, especially in thin films where grain size approximates film thickness. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359898
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  • 3
    Electronic Resource
    Electronic Resource
    Spreading of a void along a singular surface during electromigration: A failure mode (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 194-196 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Previous treatments of void shape evolution during electromigration have been restricted to nonsingular void surfaces. We consider the lateral spreading of a void when its leading surface is a singular facet. The facet may nucleate at the leading surface of a void migrating within one grain or may develop when a singular surface is exposed by impingement of the void at a (transverse) grain boundary. Advance of the facet requires a source of steps that we assume to be absent; void spreading results. A stationary void shape is possible when a dimensionless parameter is less than a critical value (estimated), whereas above this value the void spreads indefinitely. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.118353
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  • 4
    Electronic Resource
    Electronic Resource
    Voltage- and Ca2+-Dependent Burst Generation in Neuroendocrine Dahlgren Cells in the Teleost Platichthys flesus (2004)
    Oxford, UK : Blackwell Science Ltd
    Journal of neuroendocrinology 16 (2004), S. 0 
    Details
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The neuroendocrine Type 1 Dahlgren cells of the caudal neurosecretory system of the flounder display characteristic bursting activity, which may increase secretion efficiency. The firing activity pattern in these cells was voltage-dependent; when progressively depolarized, cells moved from silent (approximately −70 mV), through bursting and phasic to tonic firing (〈 −65 mV). Brief (10 s) evoked bursts of spikes were followed by a slow after-depolarization (ADP; amplitude up to 10 mV, duration 10–200 s), which was also voltage-dependent and could trigger a prolonged burst. The ADP was significantly reduced in the absence of external Ca2+ ions or the presence of the L-type Ca2+ channel blocker, nifedipine. BayK 8644 (which increases L-type channel open times) significantly increased ADP duration, whereas the Ca2+-activated nonselective cation channel blocker, flufenamic acid, had no effect. Pharmacological blockade of Ca2+-activated K+ channels, using apamin and charybdotoxin, increased the duration of both ADP and evoked bursts. However, action potential waveform was unaffected by either apamin/charybdotoxin, nifedipine, BayK 8644 or removal of external Ca2+. The short duration (approximately 100 ms), hyperpolarization-activated, postspike depolarizing afterpotentials (DAP), were significantly reduced by nifedipine. We propose that long duration ADPs underlie bursts and that short duration DAPs play a role in modulation of spike frequency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2826.2004.01238.x
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  • 5
    Electronic Resource
    Electronic Resource
    Determinants of cord-blood IgE concentrations in 6401 German neonates (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Allergy 50 (1995), S. 0 
    Details
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: For screening atopy risk in 6401 (84%) of all infants born during the year 1990 in six obstetric departments of five German cities, cord-blood IgE values were determined with CAP-RAST-FEIA. After cases with elevated IgA values had been excluded, 25 % of the values were above the detection limit of 0.35 kU/1, and 8.5% were above 0.9 kU/1. Boys had significantly higher values than girls (P≤0.001). The distribution of values was significantly different for different nationalities of mothers (P≤0.001). The percentage of elevated values (≥0.9kU/l) increased significantly with the number of close family members with atopic history (P≤0.001). Regarding the atopic history of the father, siblings, and mother separately, only the mother's history had a significant association with the cord-blood IgE class (P≤0.001). The IgE values of 81 twin pairs correlated significantly with a coefficient of r = 0.4909 (P≤0.001). The smoking history of the parents during pregnancy showed an association with cord-blood IgE values (P≤0.02). No significant association could be shown between cord-blood IgE distribution and other variables, i.e., gestational age, birth size, birth modus, Apgar score, cord-blood pH value, neonatal problems, parity, age of the mother, medication during pregnancy, educational level of mother or father, time of year, or obstetric department. It is hypothesized that, in addition to some postpartum contamination or placental transfer of maternal IgE, cord-blood IgE values are also determined by the fetal immunologic reaction to intrauterine exposure to allergens and trigger factors, and by genetic influences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1398-9995.1995.tb02484.x
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  • 6
    Electronic Resource
    Electronic Resource
    A prospective, randomized, double-blind, placebo-controlled multi-centre study on the efficacy and safety of sublingual immunotherapy (SLIT) in children with seasonal allergic rhinoconjunctivitis to grass pollen (2004)
    Oxford, UK : Munksgaard International Publishers
    Allergy 59 (2004), S. 0 
    Details
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background:  Especially in childhood, sublingual immunotherapy (SLIT) could offer advantages over subcutaneous therapy. However, limited data on its efficacy is available.Methods:  In four German centres 97 children (age 3–14 years) with allergic rhinoconjunctivitis to grass pollen were enrolled in a prospective, double-blind trial comparing SLIT (Pangramin SLIT®; ALK-SCHERAX, 0.5 μg major allergens, three times per week, 32 months) with placebo. Primary endpoint was a multiple symptom-medication score for changes in seasonal diary entries between the first and third year of the study (SLIT n = 39; placebo n = 38).Results:  The multiple symptom-medication score was significantly reduced by SLIT to 77.3% of the placebo group (P = 0.0498). The subsequent analysis of the single endpoints did not reveal significant differences for symptom scores in favour of SLIT (85.1% of placebo group; P = 0.22). However, the medication score improved significantly (67.1% of placebo group; P = 0.0025). Furthermore, secondary endpoints assessing in vivo immune responses did not differ significantly between the groups. However, retrospective analysis showed some inhomogeneity for clinical and in vitro parameters at the beginning of the study. Allergic side effects with possible relation to the study drug were reported in both groups (SLIT 49%, placebo 27%, P = 0.026).Conclusion:  Our study indicates that SLIT had a positive effect on the reduction of a multiple symptom-medication score, mainly by significantly reducing rescue medication use, but had no significant effect on symptoms alone in children with rhinoconjunctivitis to grass pollen compared with a placebo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1398-9995.2004.00627.x
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  • 7
    Electronic Resource
    Electronic Resource
    Attenuation of shock-induced inflammation in the rat liver depends on the time of TNF-α inhibition (1996)
    Springer
    Journal of molecular medicine 74 (1996), S. 51-58 
    Details
    ISSN: 1432-1440
    Keywords: Tumor necrosis factor ; Hemorrhagic shock ; Leukocyte adhesion ; Intravital microscopy ; Liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The relevance of tumor necrosis factor-α (TNF-α) inducing early inflammatory reactions in the liver after hemorrhagic shock, for example, leukocyte adhesion, has been well described. This study evaluated the anti-inflammatory effects of a monoclonal antibody against TNF-α (TN3.19.12) in terms of the time of application, namely, prior to shock induction, at the time of resuscitation, and after resuscitation. The hepatic micro-circulation was investigated by intravital fluorescence microscopy in female Sprague-Dawley rats undergoing severe hemorrhagic shock for 60 min and subsequent resuscitation. TN3.19.12 or placebo was given in a randomized and blinded manner either 60 min prior to shock induction, l min prior to resuscitation, or 15 min after the onset of resuscitation. The number of firmly adherent leukocytes in the livers of treated animals depended on the time of application of TN3.19.12. Leukocyte adhesion was significantly reduced when TN3.19.12 was given prior to shock induction or at the time of resuscitation and was less effective when administered after the onset of resuscitation. The results further confirm that TNF-α initiates very early pathological leukocyte adhesion in the liver 5 h following shock. Inhibition of leukocyte adhesion after shock, however, depends strongly on the time of TNF-α blocking. While TN3.19.12 prior to shock induction resulted in most effective attenuation, only very early treatment allowed limitation of posttraumatically increased leukocyte adhesion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00202072
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  • 8
    Electronic Resource
    Electronic Resource
    Attenuation of shock-induced inflammation in the rat liver depends on the time of TNF-α inhibition (1996)
    Springer
    Journal of molecular medicine 74 (1996), S. 51-58 
    Details
    ISSN: 1432-1440
    Keywords: Key words Tumor necrosis factor ; Hemorrhagic shock ; Leukocyte adhesion ; Intravital microscopy ; Liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The relevance of tumor necrosis factor-α (TNF-α) inducing early inflammatory reactions in the liver after hemorrhagic shock, for example, leukocyte adhesion, has been well described. This study evaluated the anti-inflammatory effects of a monoclonal antibody against TNF-α (TN3.19.12) in terms of the time of application, namely, prior to shock induction, at the time of resuscitation, and after resuscitation. The hepatic microcirculation was investigated by intravital fluorescence microscopy in female Sprague-Dawley rats undergoing severe hemorrhagic shock for 60 min and subsequent resuscitation. TN3.19.12 or placebo was given in a randomized and blinded manner either 60 min prior to shock induction, 1 min prior to resuscitation, or 15 min after the onset of resuscitation. The number of firmly adherent leukocytes in the livers of treated animals depended on the time of application of TN3.19.12. Leukocyte adhesion was significantly reduced when TN3.19.12 was given prior to shock induction or at the time of resuscitation and was less effective when administered after the onset of resuscitation. The results further confirm that TNF-α initiates very early pathological leukocyte adhesion in the liver 5 h following shock. Inhibition of leukocyte adhesion after shock, however, depends strongly on the time of TNF-α blocking. While TN3.19.12 prior to shock induction resulted in most effective attenuation, only very early treatment allowed limitation of posttraumatically increased leukocyte adhesion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00202072
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  • 9
    Electronic Resource
    Electronic Resource
    Kinetic parameters of dehydrogenase in the assessment of the response of soil to vermicompost and inorganic fertilisers (2000)
    Springer
    Biology and fertility of soils 32 (2000), S. 479-483 
    Details
    ISSN: 1432-0789
    Keywords: Keywords Vermicompost ; Mineral fertiliser ; Dehydrogenase kinetics ; Soil fertility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Kinetic parameters (V max and K m) of dehydrogenase activity were determined in order to assess the metabolic response of a soil about 1 year after organic and mineral treatments. The soil was planted with maize (Zea mays) and treated with the following fertilisers: organic (vermicompost; VC), mineral (ammonium phosphate and urea), and an organo-mineral mixture. V max, which represents a measurement of the quantity of enzyme, markedly increased in organic and organo-mineral treatments, indicating that the addition of organic matter caused an increase in dehydrogenase in the active microbial biomass. K m, representing enzyme-substrate affinity and/or different sources of the enzymes, was similar in VC-treated soil and control soil, while it doubled in organo-mineral and mineral treatments. These results suggest that the use of VC did not alter the enzyme-substrate affinity, while mineral fertiliser reduced this affinity or changed the composition and activity of soil microbiota. A positive correlation was found between V max, the metabolic index (dehydrogenase/water-soluble carbon ratio), and the soil organic matter content. The kinetic constants of dehydrogenase activity and the metabolic index may be considered valid parameters to monitor the evolution of microbiological activity in soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740000280
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  • 10
    Electronic Resource
    Electronic Resource
    Organ-spezifisches Expressionsmuster eines Kohlenmonoxid-generierenden Streßproteins (Hämoxygenase-1/Hitzeschockprotein 32) nach hämorrhagischem Schock (1997)
    Springer
    Der Anaesthesist 46 (1997), S. 339-342 
    Details
    ISSN: 1432-055X
    Keywords: Schlüsselwörter Schock ; Hämorrhagie ; Streßproteine ; Hitzeschockreaktion ; Hämoxygenase ; Key words Haemorrhage ; Shock ; Stress proteins ; Heat shock response ; Haeme oxygenase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Objective: Recent evidence suggests a possible role for Haeme oxygenase (HO)-derived carbon monoxide (CO) in the regulation of vascular tone through elevation of cyclic 3′–5′ guanosine monophosphate (cGMP). Previous work from our laboratory has shown that blockade of the HO pathway by tin-protoporphyrin-IX (SnPP) after resuscitation from haemorrhage leads to a specific and profound increase in portal resistance while neither systemic nor hepatic arterial resistance are affected. We therefore investigated the organ-specific expression pattern of the stress-inducible protein haeme oxygenase-1/heat shock protein 32 after haemorrhage and resuscitation. Materials and methods: After approval of the protocol by the local review board, male Sprague-Dawley rats (n=6/group) were anaesthetised with pentobarbitone, instrumented for assessment of central haemodynamics, and subjected to haemorrhagic hypotension (40 mm Hg for 1 h) followed by resuscitation with 60% shed blood and Ringer’s solution or a time-matched sham protocol. Samples of liver, spleen, kidney, intestine, aorta, and lungs were harvested 5 h after the onset of resuscitation and subjected to Western-blot analysis using a specific anti-rat HO-1/hsp 32 antibody (StressGen, Sidney, Canada). Results: Resuscitation with shed blood/Ringer’s solution restored central haemodynamics and acid-base status while significant haemodilution was observed. Haemorrhage and resuscitation led to strong induction of HO-1 in the liver and slight induction in aortic tissue, while no increase in steady-state protein levels was observed in the other organs studied. Conclusion:These results suggest a specific contribution of the HO/CO pathway to maintenance of low hepatic portal resistance in vivo in a clinically relevant model of haemorrhagic shock and adequate resuscitation.
    Notes: Zusammenfassung Kohlenmonoxid (CO) entsteht als Intermediärstoffwechselprodukt im Hämabbau und kann nach neuesten Erkenntnissen ähnlich wie Stickstoffmonoxid über Aktivierung der Guanylatzyklase vasodilatorische Wirkungen entfalten. Für die endogene Bildung von CO ist ausschließlich die mikrosomale Hämoxygenase (HO) verantwortlich, die als konstitutives Enzym (HO-2) sowie in einer streßinduzierbaren Isoform (HO-1 oder Hitzeschockprotein 32) vorliegt. Hemmung des Hämstoffwechsels nach Schock und Volumentherapie führt nach eigenen Untersuchungen zu einer spezifischen Zunahme des Pfortaderwiderstands, ohne vasokonstriktorische Wirkungen in der systemischen Zirkulation hervorzurufen. In der vorliegenden Arbeit wurde daher das organspezifische Expressionsmuster der streßinduzierbaren Isoform des Enzyms nach hämorrhagischem Schock und Volumentherapie untersucht. Methoden und Ergebnisse: In einem kliniknah therapierten Schockmodell an der Ratte führte das Schockereignis zu einer geringfügigen Expression von HO-1 in Aortengewebe sowie zu einer ausgeprägten Expression in der Leber, während eine Induktion in anderen Organen wie Lunge, Darm oder Niere nach Hämorrhagie nicht nachweisbar war. Schlußfolgerung: Diese Ergebnisse legen nahe, daß HO-1/Hitzeschockprotein 32 in der Leber ein streßinduzierbares Vasodilatatorsystem, das zur Aufrechterhaltung der Leberperfusion nach hämorrhagischem Schock beiträgt, darstellt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001010050409
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