4 Material und Umwelt
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- 2019 (37) (entfernen)
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- DRIFTS (4)
- Leaching (4)
- Reverse glass painting (4)
- Non-invasive analysis (3)
- Raman spectroscopy (3)
- Corrosion (2)
- Diffusive gradients in thin films (DGT) (2)
- Fungus (2)
- Nosema ceranae (2)
- Osmia bicornis (2)
Organisationseinheit der BAM
- 4 Material und Umwelt (37)
- 4.1 Biologische Materialschädigung und Referenzorganismen (11)
- 4.0 Abteilungsleitung und andere (8)
- 4.3 Schadstofftransfer und Umwelttechnologien (8)
- 4.5 Kunst- und Kulturgutanalyse (7)
- 4.4 Thermochemische Reststoffbehandlung und Wertstoffrückgewinnung (5)
- 1 Analytische Chemie; Referenzmaterialien (3)
- 4.2 Material-Mikrobiom Wechselwirkungen (3)
- 1.7 Organische Spuren- und Lebensmittelanalytik (2)
- 1.2 Biophotonik (1)
Vor 30 Jahren wurde die erste BAM-Zulassung für ein Geokunststoffprodukt in der Deponietechnik ausgestellt. Seither wurden immer wieder eigene wissenschaftliche Untersuchungen durchgeführt, neue Forschungsergebnisse herangezogen und die Prüftechnik weiterentwickelt, um die Eignung und Funktionsdauer von Kunststoffdichtungsbahnen, Schutzschichten, Kunststoff-Dränelementen, geotextilen Filtern oder Bewehrungsgittern beurteilen zu können. Einige dieser Entwicklungen werden hier diskutiert.
The initial focus of this research was on the development of a general workflow for the documentation and monitoring of historical stained glass windows using structured light scanning. Therefore windows from different churches, time periods and with different corrosion and damage phenomena were scanned before and after conservation measures. To evaluate the execution of the restoration measures the data was compared using 3D inspection software to examine the differences in geometry between the two scans. Various problems had to be solved, for example, how to deal with heavily reflective surfaces and the extreme contrast between light and dark surfaces, as seen in the borders between ‘Schwarzlot’ painting and plain glass. The application of materials for matting the surfaces, such as Cyclododecane spray, was impossible due to the high accuracy of the surface measurement required for 3D inspection. Regarding the contrast differences of the surfaces, the creation of exposure fusions and the use of polarization filters to reduce reflections were tested. In addition to the general problems encountered when recording translucent surfaces, the historical glasses caused additional problems in calculating surface comparisons. For example, the windows have to be moved and turned around several times, both during the conservation process and while scanning, causing deformations of the geometry due to the flexible lead rods allowing a certain degree of movement.
This work addresses the identification of synthetic organic pigments (SOP) in eight modern reverse paintings on glass (1913–1946) by means of an in-situ multi-analytical approach. We combined the complementary properties of mobile Raman spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to overcome the main disadvantages of each method: extensive band overlapping in DRIFT spectra and fluorescence problems in Raman spectra. A collection of DRIFTS reference spectra enables a precise pigment identification by DRIFTS and establishes this method as a serious non-destructive alternative for the identification of SOP. The group of β-naphthol pigments yielded valuable results for both methods, whereas synthetic alizarin (PR83) was preferentially detected by DRIFTS. Finally, uncommon triaryl carbonium pigments and two azo group-based yellows were identified in the paintings by means of Raman spectroscopy.
Leaching processes are responsible for the release of biocides from treated materials into the environment.
Adequate modeling of emission processes is required in order to predict emission values in the framework of the risk assessment of biocidal products intended for long-term service life. Regression approaches have been applied to data obtained from the long-term monitoring of biocide emissions in experiments involving semi-field conditions. Due to the complex interaction of different underlying mechanisms such as water and biocide diffusion and desorption, however, these attempts have proven to be of limited usefulness e at least, for the available biocide emission data. It seems that the behavior of the biocide emission curve depends to a considerable extent on whichever underlying mechanism is slowest at a given point in time, thus limiting the amount of biocide available for release. Building on results obtained in the past few years, the authors propose a criterion for determining which mechanism controls the leaching process at a given point in time based on the slope of the log-log emission curve. In addition, a first-order approximation of this slope value is presented which displays advantages both in terms of computability and interpretability. Finally, an algorithm for the determination of breakpoints in the slope of the log-log emission curve is presented for the demarcation of phases within which one mechanism acts as a limiting factor.
RNA virus populations are composed of highly diverse individuals that form a cloud of related sequences commonly referred to as a ‘quasispecies’1–3. This diversity arises as a consequence of low-fidelity genome replication4,5. By contrast, DNA Virus populations contain more uniform individuals with similar fitness6.
Genome diversity is often correlated with increased Fitness in RNA viruses, while DNA viruses are thought to require more faithful genome replication. During DNA replication, erroneously incorporated bases are removed by a 3′-5′ exonuclease, a highly conserved enzymatic function of replicative DNA but not RNA polymerases. This proofreading process enhances replication fidelity and ensures the genome integrity of DNA organisms, including large DNA viruses7. Here, we show that a herpesvirus can tolerate impaired exonucleolytic proofreading, resulting in DNA virus populations, which, as in RNA viruses8, are composed of highly diverse genotypes of variable individual fitness. This indicates that herpesvirus mutant diversity may compensate for individual Fitness loss. Notably, in vivo infection with diverse virus populations results in a marked increase in virulence compared to genetically homogenous parental virus. While we cannot exclude that the increase in virulence is caused by selection of and/or interactions between individual genotypes, our findings are consistent with quasispecies dynamics. Our results contrast with traditional views of DNA virus replication and evolution, and indicate that a substantial increase in population diversity can lead to higher virulence.
A similar secretome disturbance as a hallmark of non-pathogenic Botrytis cinerea ATMT-mutants?
(2019)
The gray mold fungus Botrytis cinerea is a necrotrophic pathogen able to infect
hundreds of host plants, including high-value crops such as grapevine, strawberry and tomato. In order to decipher its infectious strategy, a library of 2,144 mutants was generated by random insertional mutagenesis using Agrobacterium tumefaciensmediated transformation (ATMT). Twelve mutants exhibiting total loss of virulence toward different host plants were chosen for detailed analyses. Their molecular characterization revealed a single T-DNA insertion in different loci. Using a proteomics approach, the secretome of four of these strains was compared to that of the parental strain and a common profile of reduced lytic enzymes was recorded. Significant variations in this profile, notably deficiencies in the secretion of proteases and hemicellulases, were observed and validated by biochemical tests. They were also a hallmark of the remaining eight non-pathogenic strains, suggesting the importance of these secreted Proteins in the infection process. In the twelve non-pathogenic mutants, the Differentiation of infection cushions was also impaired, suggesting a link between the Penetration structures and the secretion of proteins involved in the virulence of the pathogen.
Phosphorus (P) is an essential element for all life forms, and P-availability thus an important driver of a functioning agriculture. However, phosphate rock resources for P-fertilizer production are only available in a few countries. Therefore, P-recovery from waste materials has become of increasing interest during the last decade and has been investigated worldwide. In order to characterize potential novel P-fertilizers made from recycled materials, a large array of P-compound characterizations, chemical extractions and growth experiments were performed. This review bundles the work carried out in that field over the last years. Overall, P-fertilizers from recycled materials show a broad range of P-compounds with very different chemical structure and solubility. Growth experiments performed to assess their fertilizing effects display high variations for most of the products. While these experiments have demonstrated that some fertilizers made of recycled materials may reach P effects in the same order of magnitude as water-soluble phosphate rock-based fertilizers, an important limitation in their interpretation is the fact that they often vary considerably in their experimental design. The existing data show clearly that standardization of growth experiments is urgently needed to achieve comparable results. Standard chemical extractants used to assess the chemical solubility of P-fertilizers were found to be of limited reliability for predicting plant P uptake. Therefore, alternative methods such as sequential fractionation, or the extraction of incubated soil/fertilizer mixtures with standard soil extractants or with P sink methods should be tested more intensively in the future to provide alternative options to predict the P-availability of fertilizers from recycled materials.
The environmental compatibility of reactive fire-retardant coatings (intumescent paints) was investigated by a combination of leaching and ecotoxicological tests. Three representative fire-retardant coating systems were tested using two leaching procedures: “Horizontal Dynamic Surface Leaching Test” (DSLT) and the “Intermittent Immersion Test” (IIT). All eluate fractions (8 for DSLT and 9 for IIT) were analyzed for pH, conductivity, concentration of total organic carbon and selected anions und cations. Additionally, a GC-MS screening of selected fractions was conducted for identification of organic compounds. Eluate fractions 1 + 2 and fraction 7 of the DSLT were analyzed in four ecotoxicological tests (algae, daphnia, fish egg, luminescent bacteria) and in one genotoxicity test (umu). Concentration of most analytes was rather low or below limit of detection for many eluates. Analytes detected in eluates of all three products are Zn, Ba, SO4(2−) and PO4(3−). Release patterns do not indicate a general trend: some compounds show maximum release in the first fractions while for others the maximum was observed in later test stages. Ecotoxic effects in eluates were found, which were higher in the eluate fraction 7 (maximum lowest ineffective dilution for luminescent bacteria (LIDL) 256) than in the eluate fraction 1 + 2 (maximum LIDL = 24). The sensitivity of the test systems was very different with highest effects for luminescent bacteria, followed by algae and daphnia and without effects in the fish egg test and umu test. A biotest battery for the comprehensive assessment is therefore advisable.
In this study, femtosecond laser-induced sub-micrometer structures are generated to modify polyethylene (PE) surface topographies. These surfaces were subjected to bacterial colonization studies with Escherichia coli and Staphylococcus aureus as test strains. The results reveal that the nanostructures do not influence S. aureus coverage, while the adhesion of E. coli is reduced.