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  • Springer  (37)
  • American Geophysical Union  (14)
  • American Geophysical Union (AGU)
  • American Meteorological Society (AMS)
  • 2000-2004  (28)
  • 1980-1984  (23)
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Years
Year
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Earth, moon and planets 24 (1981), S. 399-405 
    ISSN: 1573-0794
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract It is proposed that the rotational angular momentum of the lower Main Sequence stars determines the intensity of their magnetic spot activity. As a consequence of this feedback coupling, the stellar rotation and the activity decay exponentially by magnetic braking of the induced stellar flare- and wind-activity. Therefore, the Sun should have rotated much faster and must have shown a very enhanced activity in its early history. This strong solar activity in the past could have had influenced the evolution of terrestrial life, and may explain the stagnation of maritime life for about 2×109 yr, the diversification of species during the Cambrian formation, and the land conquest by life in the upper Silurian system.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Czechoslovak journal of physics 32 (1982), S. 645-652 
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Anomalous dimensions of operator products are considered in the general case of non-diagonal matrix elements both in local and in non-local version of light cone expansion for quantum chromodynamics. Results are reviewed shortly.
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  • 13
    ISSN: 1573-5001
    Keywords: Byr2 ; Ras-binding domain ; sequential assignment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
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  • 14
    ISSN: 1573-5001
    Keywords: AF6 ; NMR assignment ; Ras-binding domain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 69 (1980), S. 495-503 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Linear correlations between the diameter log Φ of ring-shaped nebulae and the total number logN of embedded stars for two absolute magnitude levels of −2m and +2m for the LMC have been found. This shows that less luminous stars are also contributing towards the illumination of the nebulae. A method for the determination of relative ages of these loop nebulae is described.
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 204 (2000), S. 11-16 
    ISSN: 1573-4919
    Keywords: ions ; nitric oxide ; retina
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The divalent cation requirements of NOS activity in bovine retina homogenate supernatant were investigated. Supernatants were assayed under standard conditions (in mM: EDTA 0.45, Ca2+ 0.25, Mg2+ 4.0). In order to investigate the enzyme's dependence on divalent cations, the tissue homogenate was depleted of di- and trivalent cations by passing it over a cation-exchange column (Chelex 100). Surprisingly, NOS activity was 50-100% higher in this preparation. However, addition of either EDTA (33 μM) or EGTA (1 mM) almost fully inhibited NOS activity, suggesting a requirement for residual divalent metal cation(s). Phenanthroline or iminodiacetic acid at low concentrations had little effect on activity, suggesting no requirement for Fe2+, Zn2+ or Cu2+. Ca2+ had a moderate stimulatory effect, with an optimum activity around 0.01 mM. Mg2+ or Mn2+ had little effect at concentrations 〈 0.25 mM. However, in the presence of EDTA, Mn2+ or Ca2+ markedly stimulated NOS activity with the optimum at 0.1 mM. At high concentrations (〉 0.1-0.2 mM), all divalent cations tested (Ba2+, Zn2+, Co2+, Mn2+, Mg2+, Ca2+), as well as La3+, dose-dependently inhibited NOS activity. We propose that retinal NOS requires low concentrations of naturally occurring divalent metal ions, most probably Ca2+, for optimal activity and is inhibited by high di- and trivalent metal concentrations, probably by competition with Ca2+.
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  • 17
    ISSN: 1432-1955
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The results presented deal with the humoral immune response of golden hamsters to primary experimental infection withD. dendriticum. The development of serum antibodies has been comparatively investigated with three hamster groups (n=43) harbouring different burdens of adult flukes. The mean numbers of parasites were 11, 30, or 130 per animal. Serum antibody response was studied during an observation period of at least 331 and up to 496 days postinfection. For antibody detection the sensitivities of precipitation tests (PTs) (double diffusion test, immuno- and counterimmunoelectrophoresis), of the indirect haemagglutination test (IHAT), the complement fixation test (CFT), and the enzyme linked immuno sorbent assay (ELISA) were compared using aqueous crude fluke antigen and crude egg antigen. CFT and ELISA were most sensitive for the early detection of initial response. Thereafter all the tests employed revealed increasing antibody titres, which in general remained at constant levels and persisted until the end of the observation period with the exception of CF-antibodies. In general fluke antigen was found to be more sensitive than egg antigen. However, in CFT this antigen occasionally has been associated with unspecific inhibition of haemolysis. Comparison of the results shows that ELISA using crude fluke antigen gave the most realistic picture of the actual fluke burden. Also preliminary results on the precipitin response of rabbits (n=3) after primary experimental exposure to different numbers of metacercariae (500, 1,000, and 3,000 per animal respectively) are reported. Employing the above mentioned PTs a persisting antibody response could be demonstrated only after exposure to at least 3,000 infective larvae. The initial response was found on day 63, the observation period was 550 days.
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  • 18
    ISSN: 1432-1955
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Nach Röntgenbestrahlung embryonierterCapillaria hepatica-Eier mit 0.5, 1 bzw. 2 Krd war bei den aus den Eilarven nach Infektion vonMastomys natalensis hervorgegangenen weiblichen Nematoden die Eiproduktion zunehmend reduziert. Sie unterblieb nach Bestrahlung mit 3, 4, 5, 10, 30, 50 bzw. 70 Krd. Die Leberinvasionsfähigkeit der Parasiten war nicht beeinträchtigt. Die Infektion vonM. natalensis mit unbestrahlten embryonierten Eiern führte bereits zwischen dem 6. und 8. Tag p.i. zu einem Anstieg der Serum-GLDH-Aktivitäten. Er erreichte in dieser Phase der Infektion die Höchstwerte. Hohe Werte wurden auch nach Beginn der Patenz festgestellt. Die erhöhte Aktivität hielt bis zum Versuchsende am 36. Tag p.i. an. Nach Infektion mit 2,2 bzw. 5 Krd bestrahlten Eiern waren die Aktivitätserhöhungen geringer und traten im Verlauf der Infektion mit 5 Krd bestrahlten Eiern auch verzögert auf. Nach Infektion mit unbestrahlten Eiern ließen sich im indirekten Hämagglutinationstest mit wässrigem Antigenextrakt aus nicht embryonierten Eiern die ersten Antikörper bereits 1 Woche p.i. nachweisen. Die Höchsttiter traten mit Beginn der Patenz auf. Nach anschließendem fast plateauartigem Verlauf setzte etwa mit Beendigung der Eiproduktion ungefähr um die 7. Woche p.i. ein kontinuierlicher Titerabfall ein. Der Antikörpernachweis gelang jedoch bis zum Versuchsende 17 Wochen p.i. — Nach Infektionen mit 2,2 bzw. 5 Krd bestrahlten Eiern gelang der Antikörpernachweis erst später. Die erreichten Höchsttiter waren geringfügig (2,2 Krd) bzw. auffällig (5 Krd) niedriger. Der anschließende Titerabfall führte zur Annäherung an die Werte nicht infizierterM. natalensis. Die Ergebnisse werden vergleichend mit an anderer Stelle mitgeteilten Befunden zur Leberpathohistologie der Capillariasis diskutiert.
    Notes: Abstract X-ray irradiation of embryonatedCapillaria hepatica eggs using 0.5, 1, or 2 Krd resulted in a progressive decrease of egg production of the female nematodes which had developed from irradiated first stage larvae inMastomys natalensis. Egg production did not occur after irradiation with 3, 4, 5, 10, 30, 50, or 70 Krd. The capacity of the parasites to invade the liver was not influenced. Infection ofM. natalensis using unirradiated eggs was followed by an increase of serum-GLDH-activities between days 6 and 8 post infection reaching maximum values in this period of infection. Furthermore high values have been determined after the beginning of patency. Increased activity persisted up to the end of the experiment on day 36 post infection. After infection with eggs which had received 2.2 or 5 Krd the increase of serum-GLDH-activities was decreased and occurred later in the course of infection using 5 Krd irradiated eggs. Antibodies could be demonstrated as early as one week after infection with unirradiated eggs. Employing the indirect haemagglutination test, using an aqueous extract from non-embryonated eggs as antigen, maximum titres occurred at the beginning of patency. After a nearly plateau-like course titres began to drop about 7 weeks p.i., i.e. about the end of egg production by the female worms, but antibodies were still detectable 17 weeks p.i. (end of the observation period). After infection with eggs which had received 2.2 or 5 Krd antibody development was delayed. Maximum titres were some-what (2.2 Krd) or markedly (5 Krd) lower. Thereafter titres dropped to values comparable to those of uninfectedM. natalensis. The results are compared with published reports on the pathohistology of capillariasis.
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  • 19
    ISSN: 1615-6110
    Keywords: Lichens ; Rhizocarpon effiguratum ; Rhizocarpon norvegicum ; Rhizocarpon pusillum ; Rhizocarpon superficiale ; Depsides ; depsidones ; pulvinic acid derivatives ; chemotaxonomy ; high performance liquid chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The secondary lichen products of 31 specimens of theRhizocarpon superficiale group are examined by high performance liquid chromatography (HPLC). At 260 nm 13 different compounds have been detected. 6 of them are well-known lichen acids which occur in nearly all the species; but proportions are different and constant for each species. An analytical key is added.
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  • 20
    ISSN: 1432-1955
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Crude aqueousLitomosoides carinii adult worm extract was used as antigen for the detection of antibodies in sera from African patients with proven onchocerciasis (n=45) resident in rural endemic areas of Togo and Sierra Leone. In 71% of cases this extract was found to produce 1 to 5 precipitation arcs in immunoelectrophoresis. Using a crude aqueous extract from adultOnchocerca volvulus, precipitation tests were positive in 75% of cases. The complexity of theL. carinii curde extract was shown by PAG-disc electrophoresis, PAG-electrofocusing, immunoelectrophoresis and crossed immunoelectrophoresis with the appropriate rabbit-antiserum. An antigen detecting onchocercal antibodies was isolated by two step preparative flat bed electrofocusing in granulated gel (PEGG). The antigen (pI 6.55, molecular weight 55 to 60 kd as estimated by SDS-PAG electrophoresis) was very suitable for antibody demonstration in double diffusion test and immunoelectrophoresis. Preliminary controls for specificity were performed by diffusing the antigen against sera from human and animal helminthoses including filarial infections. In contrast to the crudeL. carinii extract no reaction was observed with sera from helminthic infections others than filariasis.
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