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  • 1980-1984  (6)
  • 1975-1979  (8)
  • 1945-1949  (4)
  • 1
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 296 (1982), S. 821-825 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Sr and Nd isotope ratios are reported for 17 mid-ocean ridge basalts and for 11 oceanic islands and island groups. Data from the Azores, Samoa and the Society Islands diverge significantly from the mantle array. These results are not explained by binary mixing of depleted and undepleted mantle ...
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2048
    Keywords: Abscisic acid ; Acer ; Bud dormancy ; Dormancy (bud)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Levels of free-abscisic acid and “boundabscisic acid” (alkaline hydrolyzable abscisic acidesters) in replicated samples of terminal vegetative buds of sycamore trees were measured during natural emergence from winter dormancy by gas chromatographic methods together with isotope dilution estimation of recovery rates. Not until after the buds had been released from true dormancy in January by winter chilling did any clear change occur in either abscisic acid (ABA) fraction, or in total ABA, on any basis of comparison. The percentage of total ABA present as the free acid declined at the end of true dormancy to approximately two-thirds of its value in the earlier winter months. It is concluded that glucosylation of ABA is unlikely to play a major part in the mechanism of release from dormancy in vegetative sycamore buds. At the end of true dormancy there was a large transient increase in what appeared to be phaseic acid, but this was not accompanied by any marked decrease in either free- or bound-ABA.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1440
    Keywords: Herbizide ; Paraquat ; Vergiftung ; Hämoperfusion ; Herbicides ; Paraquat ; Intoxication ; Hemoperfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary “Continuous hemoperfusion” (8 h/day for 2–3 weeks) was performed in two patients suffering from severe paraquat intoxication. On account of paraquat plasma concentrations a fatal outcome due to pulmonary fibrosis would have been expected in both cases. However, both patients survived following “continuous hemoperfusion” therapy. Coated activated charcoal seems to have a higher affinity for paraquat than lung tissue.
    Notes: Zusammenfassung „Kontinuierliche Hämoperfusion“ (ca. 8 h täglich während 2–3 Wochen) wurde wegen Paraquatvergiftung an zwei Patienten durchgeführt, bei denen aufgrund der Höhe der Paraquat-Plasma-Spiegel mit der Entwicklung einer letalen Lungenfibrose gerechnet werden mußte. Beide Patienten konnten durch diese Maßnahme der „Kontinuierlichen Hämoperfusion“ gerettet werden. Beschichtete Aktivkohle scheint eine größere Affinität für Paraquat zu haben als die Lungen.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 306 (1983), S. 431-436 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Analyses on fresh glass samples of mid-ocean ridge basalt yield a uniform ratio K/U = 12,700 ± 200. In contrast, Th/U increases systematically with Th concentration. From these results we calculate an upper limit (1.5 pW kg−1) and a best estimate (0.6 pW ...
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 33 (1975), S. 251-257 
    ISSN: 1432-0738
    Keywords: Herbicides ; Intoxication ; Diquat ; Paraquat ; Hemodialysis ; Herbizide ; Intoxikation ; Diquat ; Paraquat ; Hämodialyse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei einer Patientin mit schwerer Diquat-Intoxikation wurden extrakorporale Hämodialysen durchgeführt. Die Diquat-Clearance betrug im Mittel 3,17 ml/min. Durch 11,5stündige Dialyse konnten nur 0,84 mg Diquat aus dem Blutserum eliminiert werden. Die Hämodialyse ist daher kein geeignetes Verfahren, um einen Tag nach der Ingestion toxikologisch relevante Mengen Diquat aus dem Organismus zu entfernen.
    Notes: Abstract Extracorporeal hemodialyses were carried out in a female patient with severe diquat intoxication. Diquat clearance was on average 3.17 ml/min. Only 0.84 mg diquat could be eliminated from the blood serum by 11.5 hrs of dialysis. Hemodialysis is therefore not an efficient technique for removing amounts of diquat from the organism that are toxicologically relevant one day after ingestion.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 35 (1979), S. 587-588 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Our first aim was to simplify the spacer-synthesis for affinity-chromatography of cholinergic proteins. Further-more we synthesized 2 new inhibitors which proved to be useful for purification of acetylcholine-receptor protein.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Contributions to mineralogy and petrology 84 (1983), S. 382-389 
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract This paper presents a method for the systematic trace element modelling of a cogenetic suite of lavas. It is based on the geochemical inversion technique of Allègre and coworkers and utilizes the variations in the trace element concentrations of the lavas to calculate initial concentrations and source mineralogy. We reduce this inversion to a simple, step-by-step procedure: (1) correcting for fractional crystallization; (2) testing the inferred primary melt compositions for consistency with a model of equilibrium partial melts (with constant partition coefficients) formed from identical sources; (3) estimating the proportions of mineral phases entering the melt; (4) computing concentrations and bulk partition coefficients in the initial source relative to the concentration of a common reference element; (5) estimating relative mineral abundances in the source. Except for the fractionation correction, the calculations are done element by element using a direct analytic solution. For the purpose of comparison we apply this method to the same set of data used by Minster and Allègre (1978), a suite of lavas from Grenada (lesser Antilles) originally analyzed by Shimizu and Arculus (1975). The results of both methods agree well for the source abundances of the light REE, whereas the heavy REE abundances are shown to be poorly constrained by the data. Both methods require residual clinopyroxene and garnet in the source, but the ratio of these minerals is not well constrained. We are unable to reproduce the shape of D0 pattern (=bulk partition coefficients of the initial source) given by Minster and Allègre. The reason for this cannot be evaluated without repeating their calculations in detail. The set of data from Grenada is useful for comparison of the methods only, because it is now known from isotopic data that the samples are not truly cogenetic. Possibly better suited sets of samples for petrogenetic modelling are presented in parts II and III of this series.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0738
    Keywords: Chenodeoxycholic acid ; Chimpanzee ; Conjugation ; Lithocholic acid ; Sulfation ; Toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Um im Schimpansen die hepatische Biotransformation der primären Gallensäure Chenodeoxycholsäure und deren wichtigstem bakteriellen Metaboliten, Lithocholsäure zu charakterisieren, wurde ein Gemisch aus Spurenmengen von14C-Lithocholsäure und3H-Chenodeoxycholsäure intravenös in zwei Tiere mit Gallenfistel injiziert. Die chemische Form der Radioaktivität, die in der Galle erschien, wurde dünnschichtchromatographisch ermittelt. Etwa 80% der Chenodeoxycholsäure und 70% der Lithocholsäure wurden innerhalb von 90 min ausgeschieden. Die Chenodeoxycholsäure war vollständig konjugiert und erschien vorwiegend als Chenyltaurin (52%) und Chenylglycin (37%). 11% erschienen in einer Form, die bisher nicht identifiziert wurde. Lithocholsäure wurde vollständig als Taurin- und Glycinkonjugat in die Galle eliminiert; der größte Teil (63%) war zusätzlich sulfatiert. Die Sulfatierung nahm stetig mit der Zeit zu und Lithocholylglycine wurde stärker sulfatiert als Lithocholyltaurin. Wir schließen aus diesen Befunden, daß der Schimpanse mit dem Menschen vergleichbar ist, indem er Lithocholsäure effektiv sulfatiert. Dadurch unterscheidet sich der Schimpanse vom Rhesusaffe und Baboon, die die Lithocholsäure nur in geringem Maße sulfatieren. Jedoch unterscheidet sich der Schimpanse auch vom Menschen und ähnelt dem Rhesusaffen und dem Baboon, indem er Gallensäure vorwiegend mit Taurin konjugiert. Die Ergebnisse lassen den Schluß zu, daß die Hepatotoxizität, die im Rhesusaffe und Baboon durch Chenodeoxycholat hervorgerufen wird, und auf eine geringe Sulfatierung der Lithocholsäure zurückgeführt wird, beim Schimpansen nicht bestehen sollte.
    Notes: Abstract To characterize the hepatic biotransformation in the chimpanzee of the primary bile acid chenodeoxycholic acid (chenic) and its major bacterial metabolite lithocholic acid (lithocholic) a mixture of tracer amounts of14C-lithocholic and3H-chenic was injected intravenously into two animals with a bile fistula; the chemical form of radioactivity appearing in bile was inferred using thin layer chromatography. About 80% of chenic, and 70% of lithocholic was recovered in 90 min. Chenic was completely conjugated in bile, appearing predominantly as chenyltaurine (52%) and chenylglycine (37%). An unidentified conjugate (about 11%) was also found. Lithocholic was excreted completely as taurine and glycine conjugates, but the majority (63%) of conjugates was sulfated. Sulfation increased progressively with time, and lithocholylglycine was sulfated more than lithocholyltaurine. We conclude that the chimpanzee is similar to man in that the secondary bile acid lithocholic is efficiently sulfated. The chimpanzee thus differs from the baboon and rhesus monkey which sulfate lithocholic poorly. However, the chimpanzee differs from man and is similar to the baboon and rhesus monkey in showing preferential conjugation of bile acids with taurine. The results imply that hepatotoxicity caused by chenic, which is well documented in the rhesus monkey and baboon and has been related to defective lithocholic sulfation, should not occur in the chimpanzee.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 36 (1976), S. 43-51 
    ISSN: 1432-0738
    Keywords: Intoxication ; Paraquat ; Diquat ; Gut lavage ; Hemodialysis ; Hemoperfusion ; Schlüsselwörter ; Intoxikation ; Paraquat ; Deiquat ; Darmspülung ; Hämodialyse ; Hämoperfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen. Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse. Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.
    Notes: Abstract Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents. Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis. In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.
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  • 10
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In high-alpine soils the maximum temperature is low even during the growing season, and hence mineralisation of nutrients is reduced. The aim of this study was to investigate what sources of nitrogen and phosphorus are available for vascular plants in the alpine nival zone to support growth. Using acetylene reduction assays levels of nitrogenase activity were assessed in sealed pots containing nival zone soil and plants at an altitude above 3000 m, and in bacterial isolates of soil and rhizosphere in the laboratory. Nitrogenase activity could not be detected in bacterial isolates or in the soil containing no plants. Small quantities of ethylen (〈87 nmol·h-1 per pot) were detected in pots with Cerastium uniflorum and Poa laxa. This activity must be attributable to rhizosphere bacteria since no evidence for the presence of cyanobacteria could be obtained. Other sources of nitrogen for the plants were detected in the form of ammonium and nitrate in soil water and in snow melt water. These solutions also contained extractable phosphorus in quantities normally considered to be sufficient for growth. Analyses of the internal concentration of nitrogen and phosphorus also suggested that these elements were present in adequate amounts in these plants. It was considered that soil and snow melt water together may provide sufficient nitrogen and phosphorus to support the extremely small annual growth increment of nival zone plants.
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