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  • 11
    Electronic Resource
    Electronic Resource
    The sulphides in griquaite and garnet-peridotite xenoliths in kimberlite (1973)
    Springer
    Contributions to mineralogy and petrology 39 (1973), S. 1-16 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The sulphides in the garnet-peridotite and griquaite xenoliths in kimberlite were investigated microscopically, and the mineral assemblages and textural relationships are discussed. The results of a geochemical investigation of the K2O, Na2O, Cu, Co, Ni, and Zn contents of these nodules are discussed. It is concluded that the massive basaltic kimberlites (Frick, 1970) are the only kimberlites on which meaningful geochemical investigations could be attempted. It was also found that, owing to the amount of contamination induced by the kimberlite magma, neither the xenoliths nor the mineral separates derived from them can be used for a meaningful geochemical investigation. In an investigation of the upper mantle most of the geochemical work on these inclusions can therefore be disregarded. Two stages of sulphide mineralization can be distinguished in the garnet-peridotite xenoliths, and at least one stage of sulphide mineralization in the griquaite inclusions. The textural evidence supports a cumulate origin for the garnet-peridotite xenoliths, and strongly contradicts such an origin for the griquaite inclusions. It appears that the sulphides in the griquaite xenoliths form during the partial melting of the griquaite, as an immisible sulphide liquid. Although inconclusive, evidence does exist that the sulphur is disseminated in the lattices of the griquaitic clinopyroxenes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00374242
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  • 12
    Electronic Resource
    Electronic Resource
    Uptake and sequestration of ouabain and other cardiac glycosides inDanaus plexippus (Lepidoptera: Danaidae): Evidence for a carrier-mediated process (1995)
    Springer
    Journal of chemical ecology 21 (1995), S. 557-575 
    Details
    ISSN: 1573-1561
    Keywords: Danaus plexippus ; cardenolides ; uptake ; carrier ; sequestration ; chemical defense ; midgut ; integument
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Larvae ofDanaus plexippus feed almost exclusively on milkweed species of the genusAsclepias, whose characteristic secondary metabolites are cardiac glycosides (CGs). Aposematic last-instar larvae were fed with ouabain and other cardiac glycosides of differing polarities. Time course experiments show that ouabain is sequestered in the integument within 48 hr after feeding, whereas midgut tissue and hemolymph function as transient CG storage compartments. About 63% of ouabain was transferred from larvae to the butterflies, whereas 37% of ouabain was lost with larval and pupal exuviae and with the meconium. The main sites of storage in imagines are wings and integument. If mixtures of CGs are fed toD. plexippus larvae, differential sequestration can be observed: The polar ouabain contributes 58.8% of total CGs, followed by digitoxin (19.6%), oleandrin (10.6%), digoxin (4.9%), digoxigenin (4.6%) and proscillaridin A (1.5%). Thus, uptake and sequestration must be selective processes. Uptake of [3H]ouabain in vitro by isolated larval midguts was time-, pH-, and temperature-dependent and displayed an activation energy of 49 kJ/mol. Furthermore, the in vitro uptake of ouabain was inhibited (probably competitively) by the structurally similar convallatoxin. These data provide first evidence that ouabain uptake does not proceed by simple diffusion but with the aid of a carrier mechanism, which would explain the differential cardenolide uptake observed in living larvae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02033701
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  • 13
    Electronic Resource
    Electronic Resource
    Elektroanalyse (1932)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 87 (1932), S. 214-224 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01332979
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  • 14
    Electronic Resource
    Electronic Resource
    Literatur (1933)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 91 (1933), S. 366-368 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01336395
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  • 15
    Electronic Resource
    Electronic Resource
    Wismut (1930)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 80 (1930), S. 387-391 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01371508
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  • 16
    Electronic Resource
    Electronic Resource
    Intraoperative Flußmessung koronarer Bypassgefäße mit der Ultraschall-Transit-Zeit-Methode (1999)
    Springer
    Zeitschrift für Kardiologie 88 (1999), S. 773-779 
    Details
    ISSN: 1435-1285
    Keywords: Key words Coronary artery bypass grafting – coronary flow – transit time flowmeter ; Schlüsselwörter Aortokoronare Bypassoperation – Koronarfluß– Ultraschall-Transit-Zeit-Methode
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Ziel der Studie war es zu untersuchen, ob typische Flußcharakteristika für A.-mammaria-Bypassgefäße zum Ramus interventricularis (IMA) und venöse Bypassgefäße zu Zielgefäßen der Lateral- und Hinterwand des Herzens bestehen (ACVB). Bei 21 Patienten wurden insgesamt 25 Bypassgefäße untersucht (12/25 IMA, 13/25 ACVB). Mit der Ultraschall-Transit-Zeit-Methode wurden für 60 s Flußdaten mit einer zeitlichen Auflösung von 5 ms akquiriert. Signifikante Unterschiede zeigten sich bei den Flußmustern der beiden Bypasstypen. Die A.-mammaria-Bypassgefäße wiesen nur eine Flußspitze nach im Mittel 45,5±18,6& ihres systolisch-diastolischen Zyklus auf. Bei den venösen Bypassgefäßen traten zwei Flußspitzen auf, eine nach 22,1±12,3% und eine nach 63,4±15,5% des systolisch-diastolischen Zyklus. Der Vergleich der beiden Bypasstypen zeigte keinen Unterschied hinsichtlich des mittleren Flusses (IMA-Bypassgefäße: 41,8±26,7 ml/min vs. ACVB: 45,3±27,0 ml/min, p = n. s.) und des maximalen Fllusses (IMA-Bypassgefäße: 75,7±55,4 ml/min vs. ACVB: 98,4±45,2 ml/min, p = n. s.). A.-mammaria-Bypassgefäße zum RIVA zeigten nur eine Flußspitze nach 45% ihres Zyklus. Venöse Bypassgefäße zu Zielgefäßen der Lateral- und Hinterwand des Herzens hatten zwei Flußspitzen, eine nach 22% und eine nach 63% ihres Zyklus. Der mittlere und maximale Fluß war in beiden Bypasstypen nicht unterschiedlich.
    Notes: Summary The aim of the study was to compare the mean and maximum flow and the flow pattern of coronary vein grafts (SVG) supplying target vessels of the inferior and lateral wall with internal mammary (IMA) grafts to the left anterior descending artery (LAD). In 21 patients 25 bypass grafts (13/25 SVG, 12/25 IMA) were investigated. Using the transit time ultrasound method, flow was measured every 5 ms and the flow data of 60 s were acquired. The flow pattern showed significant differences between both graft types during their cycle. IMA grafts showed only one peak occurring after 22.1±12.3% and the second after 63.4±15.5% of their cycle. The mean flow was not different in both graft types (IMA: 45.3±27.0 ml/min and SVG: 41.8±26.7 ml/min, p = n. s.) as it was the case for the maximum flow (IMS: 98.4±45.2 ml/min and SVG: 75.7±55.4 ml/min, p = n. s.). In conclusion, there is a different flow pattern for both graft types concerning the number and the occurrence of flow-peaks in the bypass cycle. The mean and peak flow showed no significant difference.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003920050351
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