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  • Articles: DFG German National Licenses  (13)
  • 1995-1999  (8)
  • 1980-1984  (5)
  • 1
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The molecular-beam-epitaxial growth of InxGa1−xAs on GaAs or AlyGa1−yAs leads to a variation of In content with depth, due to In segregation. However, by predepositing In at the beginning of InxGa1−xAs growth, and also thermally removing the excess In at the end, we can produce a layer with the ideal "square'' In profile. We find that the performance of AlyGa1−yAs/InxGa1−xAs/GaAs high electron mobility transistors is most enhanced by the predeposition step alone. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 19 (1996), S. 0 
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Cytosolic Ca2+· ([Ca2+]i, and elongation growth were measured in the roots of Arabidopsis thaliana. Exposure of plant tissues to high NaCl and abscisic acid (ABA) concentrations results in a reduction in the rate of growth, but the mechanism by which growth is inhibited is not understood. Both NaCl and ABA treatments are known to influence [Ca2+]i, and in this study we measured the effects of salinity and ABA on [Ca2+]i in cells from the meristematic region of Arabidopsis roots. The Ca2+-sensitive dye Fura-2 and ratiometric techniques were used to measure [Ca2+]i in cells of the root meristem region. Resting [Ca2+]i was found to be between 100 and 200 μmol m−3 in roots of untreated plants. Resting [Ca2+]i changed in response to changes in the [Ca2+] surrounding growing roots. An increase of external [Ca2+] increased [Ca2+]i; conversely, a decrease of external [Ca2+] decreased [Ca2+]i. Exposure of roots to NaCl caused a rapid reduction of [Ca2+]i, a response that was proportional to the external NaCl concentration. Thus, as the NaCl concentration was increased, [Ca2+]i in root meristematic cells decreased. Root elongation was also inhibited in proportion to the external NaCl concentration, with maximal inhibition occurring at 120 mol m−3 NaCl. The [Ca2+]i of root meristem cells also changed in response to ABA, and the magnitude of the effect of ABA was dependent upon ABA concentration. Treatment with 0.2 mmol m−3 ABA caused a momentary increase in [Ca2+]i followed by a decrease after 15 min, but 10 mmol m−3 ABA caused an immediate decline in [Ca2+]i. There was a strong positive correlation between [Ca2+]i and root elongation rates. Experiments with the ABA-deficient Arabidopsis mutant aba-3 indicated that the reduction in [Ca2+]i brought about by NaCl was unlikely to be mediated via changes in endogenous ABA. Experiments with solutes such as sorbitol, KCl and NaNO3 indicated that the effects of NaCl could be mimicked by other solutes and was not specific for NaCl.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Macmillan Magazines Ltd.
    Nature 400 (1999), S. 551-554 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The reduction in the amount of ozone in the atmospheric column over the Arctic region, observed during the 1990s,, resembles the onset of the Antarctic ozone ‘hole’ in the mid-1980s, but the two polar regions differ significantly with respect to the relative contributions of ...
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Table 1 Mammal faunas of the Marsworth channels Upper channel Elephant (indeterminate) Dicerorhinus hemitoechus (Falconer) Hippopotamus amphibius LinnMegaceros giganteus (Blumenbach) Cervus elaphus LinnBison priscus Bojanus Arvicola terrestris LinnMicrotus sp. Lower channel Canis lupus ...
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Inflammation research 44 (1995), S. S5 
    ISSN: 1420-908X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Psychopharmacology 137 (1998), S. 345-350 
    ISSN: 1432-2072
    Keywords: Key words Nicotine nasal spray ; Smoking cessation ; Nicotine replacement ; Cotinine replacement ; Expired carbon monoxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Nicotine nasal spray (NNS) is generally considered to be an effective smoking cessation aid, but all studies to date of NNS effectiveness have also utilized group therapy sessions or frequent laboratory visits to support their subjects’ stop smoking efforts. We studied 50 volunteers before they attempted to quit smoking and again at 1, 2 and 3 months after they received NNS to assist them in quitting smoking. No other stop smoking intervention was used, which more closely mimics the common practice of many individuals trying to stop smoking with the aid of a nicotine replacement product but without other supportive interventions. We found that 50% of the subjects quit smoking for the first month, 34% were still abstinent after 2 months and 32% quit smoking for 3 months. Those who quit smoking for the entire 3 months and who continued regular NNS use throughout had 67% cotinine replacement at the end of the first month, while another group which quit smoking for only the first month with the aid of NNS had 42% cotinine replacement at the end of that month. Our data confirm that NNS is an effective smoking cessation aid, but our abstinent rate at 3 months is slightly lower than in other studies in which group therapy was provided. Our data also indicate that higher NNS-induced cotinine replacement during the first month of quitting smoking (suggesting more frequent use of NNS) is associated with longer term quit-smoking success rate.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 73 (1996), S. 364-368 
    ISSN: 1439-6327
    Keywords: Salbutamol ; Ergogenic aid ; Oxygen uptake kinetics ; Cycling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of salbutamol (S) on cycling performance was examined in 15 highly trained non-asthmatic male cyclists. A double-blind, randomized cross-over design was used with S or placebo (P) administered using a metered-dose inhaler and a spacer device 20 min before each testing session. The S dose was 400 μg (four puffs), which is twice the normal therapeutic level. Subjects were habituated to all the laboratory procedures in the week prior to actual data collection. The subjects performed four tests under S and P conditions on separate days over 2 weeks. These included measurement of maximal O2 uptake $$(\dot VO_{2max} )$$ (cycle ergometry) with assessment of pulmonary function before and after, a submaximal (90% of ventilatory threshold) square-wave work transition from a base of unloaded cycling, a 60-s modified Wingate test, and a simulated 20 km time trial. No significant differences were observed in any of the dependent variables related to aerobic endurance or cycling performance between the S and P conditions. These results support other findings that an acute dose (400 μg) of S has no performance-enhancing properties.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 8 (1982), S. 95-114 
    ISSN: 1573-1561
    Keywords: Sex pheromone ; Tenthredinidae ; Pikonema alaskensis ; hydrocarbons ; dienes ; synergists ; experimental design ; ozonolysis ; mass spectra ; methoxymercuration ; Hymenoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The primary sex pheromone of the yellowheaded spruce sawfly,Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae), was found to include a series of straight-chain hydrocarbon dienes, all with the double bonds in the 9 and 19 positions and all with the (Z, Z) configuration. The major components, of 29, 31, 33, 35, and 37 carbon atoms, were synthesized. In the field and the greenhouse, the synthetic dienes were far above control levels in activity but, at least during the first hours of bioassay, were somewhat less active than the female-derived materials on a weight basis. In the field, a mixture of all five synthetic dienes, in the proportions found in the females, was more attractive than any single one, on a mole basis. In addition, (Z, Z)-9,19 dienes of 28, 30, 32, 34, 36, 38, and 39 carbons have been detected in females in minor amounts. The first five were bioassayed, and each was found to be similar in activity to the 35-carbon component when compared on a weight basis. The synthetic dienes, while active by themselves, were strongly synergized by two, more polar, Florisil fractions derived from females. Experimental design considerations are discussed.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 8 (1982), S. 83-94 
    ISSN: 1573-1561
    Keywords: Sex pheromone ; bioassay ; synergism ; sawfly ; Hymenoptera Tenthredinidae ; Pikonema alaskensis ; experimental design
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The existence of a female-produced sex pheromone in the yellowheaded spruce sawfly,Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae) was demonstrated by field and greenhouse bioassays. Virgin females, their empty cocoons (with which they were confined during handling procedures), and the hexane extract of these cocoons were attractive in the field. The only Florisil fraction of this extract consistently attractive by itself was that eluted with hexane, but three, more polar fractions (eluted with 5%, 25%, and 50% ether in hexane) each synergized the hexane fraction, increasing bioassay responses 10–30 times. Fractions derived directly from virgin females yielded comparable results. The greenhouse data corroborated the field data, except that the 5% ether-hexane fraction, while very synergistic in the field, was consistently inactive in the greenhouse.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1573-0662
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract A new method for retrieving the vertical profile of NO2 from ground-based measurements is applied to four months of measurements made at Aberdeen (57°N) during part of SESAME from November 1994 to April 1995. The retrieval method is shown to be an invaluable tool both for deriving the true NO2 vertical column and for removing the tropospheric contribution to the vertical column. This dramatically reduces the effects of tropospheric pollution in the observations and enables a more appropriate comparison with stratospheric 3-D model results. The comparison confirms the accuracy of the model's transport and its reactive nitrogen photochemistry, although there are some detailed discrepancies.
    Type of Medium: Electronic Resource
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