Showing papers by "Helmholtz Centre for Environmental Research - UFZ published in 1996"
TL;DR: In producing comparative predictions which are related explicitly to scales, pattern-oriented modelling seems to be a strategy well suited to the ‘scaling up’ from population ecology to community and ecosystem ecology.
243 citations
TL;DR: The concentration of the respective (di)nucleotides and their ratio to each other corresponds to the metabolic state of the population and is thus an indication that the intracellular level of the latter was properly fixed.
33 citations
TL;DR: Variation in the elemental concentrations depending on the kind of tooth and the sampling position have been observed, and the method is useful for epidemiological studies of the heavy metal exposure of children.
Abstract: Heavy metal levels in tooth compartments would appear to be a suitable indicator of long-term exposure A method has been developed to assess the heavy metal levels (Mn, Cu, Zn, Cd and Pb) in tooth compartments like dentin and enamel For the simultaneous determination of these elements in small dentin sample amounts (in some cases less than 1 mg) inductively coupled plasma mass spectrometry with electrothermal vaporization was the method of choice Sample preparation, method development and first results of the application of the method for the analysis of tooth compartments have been described Variation in the elemental concentrations depending on the kind of tooth and the sampling position have been observed The method is useful for epidemiological studies of the heavy metal exposure of children
20 citations
TL;DR: The low number of isolates which can be reliably identified considerably limits the usefulness of the Biolog system for analysing the composition of autochthonous bacterial soil communities.
17 citations
TL;DR: A new technique for the sample preparation and direct coupling to an Isotope Ratio Mass Spectrometer (IRMS) for the D/H-determination is described, proven by means of the IAEA-standard waters V-SMOW, GISP, SLAP.
Abstract: A new technique for the sample preparation and direct coupling to an Isotope Ratio Mass Spectrometer (IRMS) for the D/H-determination is described. 1 μl size samples of water are injected and reduced with chromium metal in a novel reaction furnace. The hydrogen gas flows directly into the IRMS and is analysed (standard/sample comparison). The reproducibility is about 1 %. The accuracy of the technique was proven by means of the IAEA-standard waters V-SMOW, GISP, SLAP.
14 citations
TL;DR: In this paper, a P/O-quotient of 1 was derived for the energy transduction of NADH obtained from formate oxidation as it was for the overall efficiency during growth on 2,4-D itself.
Abstract: Alcaligenes eutrophus JMP 134 was chemostatically grown on 2,4-dichlorophenoxyacetic acid (2,4-D) at a dilution rate of 0.06 h−1; formate was fed as an auxiliary energy source. The simultaneous utilization of both components resulted in an increase in growth yield. As an example, this figure increased from 0.18 g dry mass/g 2,4-D to 0.25 g dry mass/g 2,4-D during growth on 1 g/l 2,4-D plus 3 g/l sodium formate. The increase was correlated to energy generated from formate oxidation. Accordingly, a P/O-quotient of 1 was derived for the energy transduction of NADH obtained from formate oxidation as it was for the overall efficiency during growth on 2,4-D itself. This low energy yield was attributed to uncoupling exerted by 2,4-D. The theoretical maximum yield coefficient of 0.69 g/g could not be reached due to the limiting activity of formate dehydrogenase in the conversion of the required quantities of formate.
2 citations