ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    In:  EPIC3Tenth International Conference on Harmful Algae, St. Petersburg, (Florida) USAOctober, 21, 2002 p.
    Publication Date: 2019-07-16
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    facet.materialart.
    Unknown
    In:  EPIC3International Symposium on Genomic Studies on Toxic Microalgae, 27-28 Oct. 2003, Santiago, Chile.
    Publication Date: 2019-07-16
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    European journal of soil science 53 (2002), S. 0 
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The food dye Brilliant Blue FCF (Color Index 42090) is often used as dye tracer in field studies for visualizing the flow pathways of water in soils. Batch studies confirmed findings of other researchers that non-linear sorption is important for Brilliant Blue, especially at small concentrations (〈 10 g l−1 for our soil), and that retardation increases with decreasing concentrations as well as with increasing ionic strength of solutions. Therefore, it is not obvious if it can be used as an indicator for water flow paths as is often done. In this study, we compared the mobility of Brilliant Blue in a field soil (gleyic Luvisol) with that of bromide. Brilliant Blue and potassium bromide were simultaneously applied as a 6-mm pulse on a small plot in the field, and the tracers were displaced with 89 mm of tracer-free water using a constant intensity of 3.9 ± 0.2 mm hour−1. Both tracer concentrations were determined on 144 soil cores taken from a 1 m × 1 m vertical soil profile. The transport behaviour differed in both (i) mean displacement and (ii) spatial concentration pattern. We found the retardation of Brilliant Blue could not be neglected and, in contrast to the bromide pattern, a pulse splitting was observed at the plough pan. Numerical simulations with a particle tracking code revealed that the one-dimensional concentration profile of bromide was represented fairly well by the model, but the prediction of the double peak in the Brilliant Blue concentration profile failed. With additional assumptions, there were indications that Brilliant Blue does not follow the same flow paths as bromide. However, the question of Brilliant Blue taking the same flow pathways as bromide cannot be adequately answered by comparing both concentration distributions, because we look at two different transport distances due to the retardation of Brilliant Blue. It became obvious, however, that Brilliant Blue is not a suitable compound for tracing the travel time of water itself.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    European journal of soil science 53 (2002), S. 0 
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The quantification of the spatial heterogeneity of soil structure is one of the main difficulties to overcome for an adequate understanding of soil processes. There are different competing concepts for the type of heterogeneity, including macroscopic homogeneity, discrete hierarchy or fractal. With respect to these different concepts we investigate the structure of the pore space in one single sample (4 × 103 mm3) by analysing basic geometric quantities of the pores 〉 0.3 mm within gradually increasing subsamples. To demonstrate the relation between geometrical and functional properties we simulate gas diffusion within the three-dimensional pore space of the different subsamples. An efficient tool to determine the geometric quantities is presented. As a result, no representative elementary volume (REV) is found in terms of pore-volume density which increases with sample size. The same is true for the simulated gas diffusion coefficient. This effect is explained by two different types of pores, i.e. big root channels and smaller pores, having different levels of organization. We discuss the different concepts of structural organization which may be appropriate models for the structure investigated. We argue that the discrete hierarchical approach is the most profitable in practice.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    European journal of soil science 51 (2000), S. 0 
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Network models are idealized geometrical representations of porous media. They allow the simulation of effective hydraulic properties and of solute transport for well-defined porous structures. In this paper, the relation between pore structure and effective properties is studied using a network model which can be adjusted to predefined pore-size distributions and pore topologies. I show that pore topology can be adjusted such that quite different pore-size distributions lead to essentially identical water retention curves. This puts into question the common interpretation of the retention curve as being indicative of the pore-size distribution. However, I also found that both the hydraulic conductivity and the dispersion of a solute depend on the water retention curve and not on the particular combination of pore-size distribution and topology which make it up. This corroborates the widely used approach of inferring relative permeabilities from water retention data.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    European journal of soil science 51 (2000), S. 0 
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The inability to predict flow and transport behaviour based on a priori information demonstrates the lack of knowledge we currently have concerning transport-relevant properties or processes, or both. We present an approach in which the behaviour of effective solute transport at the scale of a soil column (100 mm) is predicted by taking into account the spatial structure of the hydraulic properties at the local scale (1 mm). The local absorption coefficients obtained from X-ray tomography, which are linearly related to bulk density, are used as local proxy for hydraulic properties. As a first approximation, two density classes were distinguished, and the three-dimensional structure of the hydraulic properties was implemented in a model of flow and transport. The local hydraulic properties were obtained from a network model, except for the absolute value of the hydraulic conductivity function which was measured. Model simulations were compared with a measured breakthrough curve determined on the same soil sample. The two agreed well, although the local hydraulic properties and parameter structure were determined independently with respect to a breakthrough experiment. Predictions of solute transport at the column scale were sensitive to the difference in saturated hydraulic conductivities of both materials, but not to the local dispersivities. The simulations demonstrate that (i) assuming validity of the Richards equation and the convection–dispersion equation on the local scale leads to a good description of the effective flow and transport behaviour at the column scale without making any assumptions about the governing processes at that scale; (ii) the dispersion parameters, which are notoriously difficult to determine, need not be determined since their effect is included explicitly; and (iii) local absorption coefficients can be used as a local proxy for the parameter field of the hydraulic properties.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 72 (1968), S. 3098-3105 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Biochemistry 36 (1967), S. 519-538 
    ISSN: 0066-4154
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Chemistry and Pharmacology , Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1573-0778
    Keywords: calcium phosphate ; CHO-K1 ; cytosolic calcium signaling ; HEK 293 ; laser scanning confocal microscopy ; transient transfection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract For the controlled production of recombinant proteinsin mammalian cells by transient transfection, it maybe desirable not only to manipulate, but also todiagnose the expression success early. Here, weapplied laser scanning confocal microscopy to monitortransfection induced intracellular Ca2+responses. We compared Chinese hamster ovary (CHO K1)versus human embryo kidney (HEK) 293 cell lines, whichdiffer largely in their transfectability. An improvedcalcium phosphate transfection method was used for itssimplicity and its demonstrated upscale potential.Cytosolic Ca2+ signaling appeared to inverselyreflect the cellular transfection fate. Virtually allCHO cells exhibited asynchronous, cytosolicCa2+ oscillations, which peaked 4 h afteraddition of the transfecting solution. Yet, most ofthe HEK cells displayed a slow and continuousCa2+ increase over the time of transfection. CHOcells, when exposed to a transfection-enhancingglycerol shock, strongly downregulated their Ca2+response, including its oscillations. When treatedwith thapsigargin, a Ca2+ store depleting drug,the number of successfully transfected CHO cells was significantly reduced. Our result points tointracellular store release as a critical componentfor the transfection fate of CHO cells, and its early detection before product visualization.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1573-0778
    Keywords: 5-HT3 receptor ; large scale ; reactor ; Semliki Forest virus ; suspension process ; transient expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The expression of recombinant proteins with the Semliki Forest Virus (SFV) system has been scaled up to bioreactor scale. As a model protein for this study the human 5-HT3 receptor was chosen. The gene for the receptor was subcloned into the SFV expression plasmid pSFV1. Virus production by in vivo packaging and production of the recombinant protein was scaled up, the latter to a reactor volume of 11.5 l. A VibromixTM agitation system was chosen to overcome aggregation problems of BHK cells in suspension. In the process, cells were first grown to a density of 106 cells/ml, the medium was then exchanged with fresh medium and the culture was infected with the recombinant virus at an estimated multiplicity of infection of 30. 24 h post infection we measured an expression level of 3 million functional 5-HT3 receptors per cell. For harvesting, the cells were pelleted by centrifugation. The receptor protein was purified in a single step (Hovius et al., 1998) by exploiting the hexa-His tag at minimal protein loss (51% yield). Experiments to optimise expression resulted in yields up to 8 million receptors per cell, when the pH of a suspension culture was controlled at pH 7.3. Rapid virus generation and protein production, high protein yields as well as successful large scale application have made the SFV expression system attractive to produce large quantities of recombinant protein in a very short time. After optimisation of the expression conditions (in particular by setting the pH at 7.3), yields were increased twofold.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...