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  • sol-gel  (4)
  • wind tunnel  (4)
  • Springer  (8)
  • 1995-1999  (8)
  • 1990-1994
  • 1965-1969
Collection
Keywords
Publisher
  • Springer  (8)
Years
  • 1995-1999  (8)
  • 1990-1994
  • 1965-1969
Year
  • 1
    Electronic Resource
    Electronic Resource
    Responses to aphid sex pheromones by the pea aphid parasitoids Aphidius ervi and Aphidius eadyi (1999)
    Springer
    Entomologia experimentalis et applicata 92 (1999), S. 227-232 
    Details
    ISSN: 1570-7458
    Keywords: aphid parasitoid ; Aphidiinae ; aphid sex pheromone ; pea aphid ; wind tunnel ; plant-host complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Aphidius ervi and Aphidius eadyi, two parasitoids of the pea aphid Acyrthosiphon pisum, were attracted to components of the aphid sex pheromone in laboratory bioassays. Pre-test experience with host aphids in the presence of aphid sex pheromone did not affect the response of A. ervi to pheromone in a 4-way olfactometer, compared with that of naive parasitoids. Aphidius ervi females exposed only to the pheromone prior to testing did not respond in the olfactometer, suggesting habituation to the foraging cue by the parasitoid. In a wind tunnel, aphid sex pheromone increased the attraction of A. ervi to the plant-host complex (Vicia faba/A. pisum), suggesting an additive effect when two different foraging cues are present simultaneously.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003820406770
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  • 2
    Electronic Resource
    Electronic Resource
    Comparative Responses of Parasitoids to Synthetic and Plant-Extracted Nepetalactone Component of Aphid Sex Pheromones (1999)
    Springer
    Journal of chemical ecology 25 (1999), S. 1481-1488 
    Details
    ISSN: 1573-1561
    Keywords: Aphid parasitoid ; aphid sex pheromone ; kairomone ; stereochemistry ; (4aS,7S,7aR)-nepetalactone ; wind tunnel ; trap plant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The responses of aphid parasitoids to completely synthetic and plant-extracted nepetalactone, a component of aphid sex pheromones, were investigated. In wind tunnel tests, Praon volucre and Aphidius ervi responded equally strongly to both plant-extracted and 99% pure synthetic (4aS,7S,7aR)-nepetalactone. In the field, aphid-infested cereal trap plants were used to test the attractiveness of plant-extracted and synthetic (4aS,7S,7aR)-nepetalactone, as well as the synthetic enantiomer (4aR,7R,7aS)-nepetalactone. There was no significant difference in parasitisation levels by Praon spp. between plants baited with the synthetic or with the plant-extracted 7S isomers. However, the 7R isomer was unattractive alone and rendered the synthetic 7S isomer unattractive when combined to form a 50% blend of the two. It is concluded that the response of aphid parasitoids to nepetalactone is influenced more by enantiomeric purity rather than the possible presence of plant-related contaminants associated with plant extraction. The results are compared with data on male aphid responses to the compounds, which indicate that plant-derived contaminants can reduce attractancy, and the implications for the manipulation of parasitoids in the field are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020872412891
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  • 3
    Electronic Resource
    Electronic Resource
    Improved Composition for Sol-Gel Rare-Earth Doped Planar Waveguides (1997)
    Springer
    Journal of sol gel science and technology 8 (1997), S. 1013-1016 
    Details
    ISSN: 1573-4846
    Keywords: sol-gel ; neodymium and erbium doped planar waveguide ; fluorescence lifetime measurement ; phosphorous and aluminium codoping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A multilayer sol-gel process has been developed in order to make highly doped rare-earth planar waveguides on silica or silicon substrates. Starting with a small range of constituents, such as SiO2, TiO2, P2O5 and Al2O3, we show that a large variety of gel compositions, with different spectroscopic behaviour, can be made when doped with rare-earths. We have doped the sol-gel films with neodymium and we have optimized their compositions by measuring the neodymium fluorescence lifetime. For a composition with 10 atom% of phosphorous, the lifetime evolution with neodymium concentration was studied and a quenching concentration was found at 1% of neodymium. We have also shown the strong influence of phosphorous or aluminium in the sol composition on the fluorescence lifetime, for a given neodymium concentration. First results on similar planar waveguides, doped with erbium, are also presented. The stability of the fluorescence lifetime over a long period of time is an other important point to be checked for these new materials: the lifetime evolution over a 9 months measurement period is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018374005608
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  • 4
    Electronic Resource
    Electronic Resource
    Improved composition for sol-gel rare-earth doped planar waveguides (1997)
    Springer
    Journal of sol gel science and technology 8 (1997), S. 1013-1016 
    Details
    ISSN: 1573-4846
    Keywords: sol-gel ; neodymium and erbium doped planar waveguide ; fluorescence lifetime measurement ; phosphorous and aluminium codoping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A multilayer sol-gel process has been developed in order to make highly doped rare-earth planar waveguides on silica or silicon substrates. Starting with a small range of constituents, such as SiO2, TiO2, P2O5 and Al2O3, we show that a large variety of gel compositions, with different spectroscopic behaviour, can be made when doped with rare-earths. We have doped the sol-gel films with neodymium and we have optimized their compositions by measuring the neodymium fluorescence lifetime. For a composition with 10 atom% of phosphorous, the lifetime evolution with neodymium concentration was studied and a quenching concentration was found at 1% of neodymium. We have also shown the strong influence of phosphorous or aluminium in the sol composition on the fluorescence lifetime, for a given neodymium concentration. First results on similar planar waveguides, doped with erbium, are also presented. The stability of the fluorescence lifetime over a long period of time is an other important point to be checked for these new materials: the lifetime evolution over a 9 months measurement period is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02436976
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  • 5
    Electronic Resource
    Electronic Resource
    Atomic Force Microscopy Study of NaOH Corroded Al2O3-TiO2-SiO2 Coatings on Glass (1998)
    Springer
    Journal of sol gel science and technology 13 (1998), S. 763-767 
    Details
    ISSN: 1573-4846
    Keywords: sol-gel ; coatings ; corrosion ; morphology ; atomic force microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Atomic force microscopy (AFM) was used to study the performance of ≈80 nm thick Al2O3-TiO2-SiO2 sol-gel coatings on glass substrates following corrosion in 1 M NaOH solutions at 60°C. The as-prepared coatings were homogeneous on a nanoscale and displayed the “glass pattern” before corrosion. Layers with different compositions behaved differently during the corrosion process. Thus, TiO2 or TiO2-dominated layers had tetragonal-like crystals on their surfaces after corrosion, possibly of anatase composition. On the other hand, layers with a molar ratio Al2O3 : SiO2 near 1 : 2 displayed a pseudo-hexagonal morphology, possibly with a nepheline (Na2O · Al2O3 · 2SiO2) composition. Layers of 5Al2O3-40TiO2-55SiO 2 were corroded is a stepwise fashion and had no special surface morphology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008669728556
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  • 6
    Electronic Resource
    Electronic Resource
    Er3+-doped Multicomponent Silicate Glass Planar Waveguides Prepared by Sol-Gel Processing (1999)
    Springer
    Journal of sol gel science and technology 14 (1999), S. 209-216 
    Details
    ISSN: 1573-4846
    Keywords: sol-gel ; silica-titania films ; planar waveguides ; Er doping ; fluorescence lifetime
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Erbium doped silica-titania planar waveguides, co-doped with ytterbium and aluminum, have been prepared by sol-gel processing, using multilayer spin-coating deposition on silicon or silica glass substrates. The Er3+ doping level varied between 0 and 2 at.%, while Yb3+ varied from 0 to 3 at.%. Aluminum was incorporated up to 15 at.% Al and it was found to have no significant effect on the refractive index of the silica-titania (80 : 20 mol%) matrix. The Er3+ fluorescence emission was flat within ±0.5 dB, between 1520 and 1560 nm. The corresponding 4I13/2 metastable level lifetime was found to decrease from 6.1 to 3.5 ms, as the Er concentration increased from 0.1 to 0.5 at.%, for films co-doped with 0.5 at.% Yb and 10 at.% Al and the fluorescence decay was essentially single exponential below a Er quenching concentration of 0.5 at.% (1.1 × 1020 ions/cm3). The lifetime appears to be limited by Er-Er interactions at higher rare-earth ion concentrations and by residual OH species in the sol-gel derived waveguides. Vacuum heat treatment at a temperature near 570°C was somewhat effective in increasing the Er fluorescence lifetime, whereas reactive atmosphere processing in CCl4 or Cl2 at a similar temperature appeared to be less effective.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008794202103
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  • 7
    Electronic Resource
    Electronic Resource
    Identification of Semiochemicals Released During Aphid Feeding That Attract Parasitoid Aphidius ervi (1998)
    Springer
    Journal of chemical ecology 24 (1998), S. 1355-1368 
    Details
    ISSN: 1573-1561
    Keywords: Homoptera ; Aphididae ; Hymenoptera ; Braconidae ; tritrophic interactions ; host foraging ; plant volatiles ; semiochemicals ; induction ; synomones ; wind tunnel ; GC-EAG ; Acyrthosiphon pisum ; Aphidius ervi ; Vicia faba ; Aphis fabae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Herbivore induced release of plant volatiles mediating the foraging behavior of the aphid parasitoid Aphidius ervi was investigated using the pea aphid, Acyrthosiphon pisum, feeding on broad bean, Vicia faba. Behavioral responses were studied using an olfactometer and a wind tunnel. Volatiles obtained by air entrainment of aphid infested plants were more attractive to A. ervi than those from uninfested plants, in both behavioral bioassays. GC-EAG of both extracts showed a number of peaks associated with responses by A. ervi, but with some differences between extracts. Compounds giving these peaks were tentatively identified by GC-MS and confirmed by comparison with authentic samples on GC, using two columns of different polarity. The activity of pure compounds was further investigated by EAG and wind tunnel assays. Results showed that, of the compounds tested, 6-methyl-5-hepten-2-one was the most attractive for A. ervi females, with linalool, (Z)-3-hexen-1-yl acetate, (E)-β-ocimene, (Z)-3-hexen-1-ol, and (E)-β-farnesene all eliciting significantly more oriented flight behavior than a solvent control. Foraging experience significantly increased parasitoid responses to these compounds, with the exception of (E)-β-farnesene. Time-course GC analysis showed that feeding of A. pisum on V. faba induced or increased the release of several compounds. Release of two of these compounds (6-methyl-5-hepten-2-one and geranic acid) was not induced by the nonhost black bean aphid, Aphis fabae. During the analysis period, production of (E)-β-ocimene remained constant, but 6-methyl-5-hepten-2-one, linalool, geranic acid, and (E)-β-farnesene appeared during the first day after A. pisum infestation and increased in concentration with increasing time of aphid feeding.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021278816970
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  • 8
    Electronic Resource
    Electronic Resource
    Relative importance of semiochemicals from first and second trophic levels in host foraging behavior ofAphidius ervi (1996)
    Springer
    Journal of chemical ecology 22 (1996), S. 1591-1605 
    Details
    ISSN: 1573-1561
    Keywords: Aphidius ervi ; host location ; olfaction ; plant volatiles ; aphid feeding ; Acyrthosiphon pisum ; Aphis fabae ; wind tunnel ; Y-tube olfactometer ; tritrophic interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The responses of femaleAphidius ervi to odors from a host food plant (Vicia faba), host aphids (Acyrthosiphon pisum), nonhost aphids (Aphis fabae), and aphid-plant complexes were investigated in a specially designed wind tunnel and a Y-tube olfactometer. In single-target (no-choice) and two-target (dual-choice) experiments, plant volatiles played a crucial role in the host foraging behavior ofA. ervi. The odor from theA. pisum-plant complex elicited the strongest responses byA. ervi females, followed by the odor from plants previously damaged by the feeding ofA. pisum. There was a significantly weaker response to odor fromA. pisum in the absence of the plant and to undamaged plants. Similarly, mechanically damaged plants and plants infested with the nonhost aphidA. fabae did not elicit strong responses. A plant that had been damaged byA. pisum and subsequently washed with distilled water was as attractive as an unwashed, previously infested plant.Aphidius ervi probably overcomes the reliability-detectability problem by selectively responding to herbivore-induced, volatile, semiochemical cues emitted by the first trophic level and by distinguishing between the volatiles induced by host and nonhost aphids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272400
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