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  • 1
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Es wird ein halbanalytisches Berechnungsverfahren zur Bestimmung der instationären Temperaturen von Haut-Steg-Verbindungen vorgestellt, das den Einfluß einer Fügung zwischen Haut (Flansch eines Winkels) und Steg numerisch berücksichtigt. Ausgehend von den Temperaturfunktionen, die sich unabhängig voneinander für die beiden Strukturelemente bei gegebenen Randbedingungen und konstanter Randtemperatur an der Verbindungsstelle ergeben, kann der thermische Übergangswiderstand der Fügung (z.B. einer Nietverbindung) durch Formulierung einer Wärmebilanz sowohl oberhalb als auch unterhalb der Fügung auf einfache Art in die Berechnung einbezogen werden. Das Verfahren, das am Beispiel von Flugzeugstrukturen (versteifte Tragflügelgurtplatte, Tragflügelkasten) für den Sprung der Fluidtemperatur und des Wärmeübergangskoeffizienten untersucht wird, läßt sich auch auf ähnliche Probleme in anderen Ingenieursdisziplinen übertragen.
    Notes: Abstract A semi-analytical method is presented for calculating temperature transients in skin-web-configurations including the effect of a thermal joint resistance at the web-skin (flange) junction. Based on the temperature functions independently developed for both elements at given boundary conditions and constant junction temperature the joint resistance can be taken into account easily by formulation of a heat balance above and below the joint. The method, here applied to aircraft structures (stiffened panel, wing box) for the step functions of fluid temperature and heat transfer coefficient can also be extended to similar problems in other engineering fields of application.
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  • 2
    ISSN: 1432-2242
    Keywords: Vigna aconitifolia ; Co-cultivation ; Agrobacterium tumefaciens ; Kanamycin resistance ; Nopaline synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A simplified protoplast regeneration system for Vigna aconitifolia was developed. A plating efficiency of 60% was obtained using mesophyll protoplasts from 10-day-old seedlings. By co-cultivation of protoplasts with Agrobacterium tumefaciens containing the Ti plasmid derivative pGV 3850∶1103 neo kanamycin-resistant colonies were obtained; 23% of the transformed lines showed expression of the nonselected co-transferred nopaline synthase gene. Transformation was confirmed by Southern blot analysis using a nonradioactive detection system. The plant cultivar used was an important factor in determining transformation frequencies since one of the cultivars had an 85 fold higher transformation rate than the other.
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  • 3
    ISSN: 1432-2242
    Keywords: Brassica nigra ; Direct gene transfer ; Petuniahybrida ; Plasmid degradation rate ; X-ray
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In P. hybrida and B. nigra an enhancement of transformation rates (direct gene transfer) of about six to seven-fold was obtained after irradiation of protoplasts with 12.5 Gy (X-ray). The effect of protoplast irradiation was similar in experiments where protoplasts were irradiated 1h before transformation (X-ray/DNA) or 1h after completion of the transformation procedure (DNA/X-ray). Increased X-ray doses up to 62.5 Gy resulted in further enhancement of percentages of transformed colonies, indicating a correlation between relative transformation frequencies (RTF) and the doses applied. Estimation of degradation rates of plasmid sequences in plant protoplasts yielded a reduction of plasmid concentration to 50% 8–12 h after transformation. In 1-day-old protoplasts, the level of plasmid fragments dropped to 0%–10% compared to 1h after transformation. The results demonstrate that the integration rates of plasmid sequences into the plant genome may in part be governed by DNA repair mechanisms. This could be an explanation for the observed genotypic dependence of transformation rates in different plant species and plant genotypes. Gene copy number reconstructions revealed enhanced integration rates of plasmid sequences in transformed colonies derived from irradiated protoplasts.
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  • 4
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary N-(o-Carboxybenzoyl)-dl-glutamic acid imide anddl-glutamic acid imide · HCl did not lead to fetal malformations after i.p. administration to pregnant mice; the injected solutions contained 25% Tween 20. Thus, of the 12 hydrolysis products of thalidomide only those 3 which contain the phthalimide moiety show teratogenic activity, i.e. 2-phthalimido-dl-glutaramic acid, 4-phthalimido-dl-glutaramic acid and 2-phthalimido-dl-glutaric acid.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Insectes sociaux 13 (1966), S. 305-309 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary During a longer period the simultaneously occurring raids, from two adjucent nests ofPolyergus rufescens, were exactly controlled with regard to direction, processional length and rate of collected pupae. The direction of the raids of one of the nests was steerd by placingServiformica pupaee opposite to the recognized directional tendency of the raid. The success of both raids was equal in both cases. It can therefore be assumed that in the normal case neither the individual «Kundschafter» (Scoucts (after Forel) nor the «activators» (afterDobrzanska et al.) contribute essentially to the suscess of the raid.
    Notes: Zusammenfassung An benachbarten Nestern vonPolyergus rufescens wurden gleichzeitig erfolgende Raubzüge genauestens hinsichtlich Richtung, Auszugslänge und Erfolg kontrolliert. Dabei wurde jeweils bei einem Nest die Auszugsrichtung durch Auslegen vonServiformica-Puppen entgegengesetzt zur erkennbaren Auszugs-Tendenz gelenkt. Die Erfolge beider Raubzüge sind nicht voneinander verschieden. Es kann daher angenommen werden, dass im Normalfall weder die einzelnen “Kundschafterinnen» (nach Forel) noch die «Aktivistinnen» (nachDobrzanska et al.). wesentlich zumErfolg des Raubzuges beitragen.
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  • 6
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary It is shown that two bacterial diseases ofPeriplaneta americana are accompanied by a significant increase of body temperature of the insect.
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  • 7
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The teratogenicity of 3 hydrolysis products of thalidomide, 2-(o-carboxybenzamido)-glutaric acid, phthalic acid and glutamic acid, was determined by administering 25% Tween 20 i.p. to pregnant SWS-mice. Under these experimental conditions, the tested products were devoid of any teratogenic properties, whereas thel-isomer of phthaloyl-glutamic acid showed the well-known embryotoxic and teratogenic activity.
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  • 8
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Skeletal defects were observed in the off-spring of SWS-mice following i.p. administration of phthaloyl-l-glutamic acid, a metabolite of thalidomide. The fetuses of animals which receivedl-glutamic acid in addition to the teratogenic drug, did not show any malformations, whereas concurrent i.p. administration of thed-isomer of glutamic acid failed to reverse teratogenicity induced by phthaloyl-l-glutamic acid.
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  • 9
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Phthaloyl-dl-glutamic acid, a metabolite of thalidomide, was found to exert a teratogenic effect after i.p. administration to pregnant mice. The injected solution contained Tween 20 as solubilizer.
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  • 10
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The teratogenicity of optical antipodes of phthaloyl-glutamic acid, a metabolite of thalidomide, was determined by administering i.p. to pregnant mice. The injected solution contained Tween 20 as solubilizer. Under the conditions of experiment thel-isomer was found to be embryotoxic; whereas thed-form was devoid of any embryopathic properties.
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