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Eingeladener Vortrag
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In a rapidly evolving world, the demand on raw materials is increasing steadily and many technologies are dependent on a secure supply of hi-tech metals. Recently, scandium (Sc) has attracted attention since its use in high strength Al-alloys and solid-oxide-fuel-cells strongly improves the performance of those materials.
The element Sc is not exceptionally rare but quite resistant to geochemical enrichment processes, it is scarcely found enriched to high concentrations and is recovered as a by-product. Since Sc enrichment in Greek bauxite residues was shown by Ochsenkühn-Petropoulou et. al (1994), intensive research on this material and development of efficient Sc-recovery methods is ongoing.
This study investigates Sc-bearing species in bauxite residues from alumina production. It aims to provide direct evidence about the Sc-speciation’s in those secondary resources and tries to find the link to speciation’s in primary resources, e.g. bauxites and laterites.
Therefore, Sc K edge XANES (X-ray absorption near edge structure) spectroscopy is performed using synchrotron radiation to determine the presence of certain Sc-components and distinguish between adsorbed and chemically bonded Sc as was shown for lateritic deposits in Australia by Chassé et al. 2016. For comparison, reference standards of Sc-bearing and Sc-adsorbed species are synthesized. Indirect inferences from leaching behavior of bauxites, in cases supported by analyses with LA-ICP-MS, suggest Sc to be associated with either iron- or aluminum phases (Vind et al. 2017); (Suss et al.). It remains unclear how different primary materials influence Sc-speciation in the bauxite residue. Therefore, a comparison between different European bauxite residues is made in this study. The investigations should help to understand Sc chemistry and
behavior in different primary and secondary materials and provide fundamentals for metallurgical processing. The research is incorporated in the SCALE project (GA No. 730105) funded by EU Horizon 2020 research and innovation program.
Museums worldwide are equipped with different display cases. Exhibit display cases should protect cultural objects from dust as well as from mechanical and physical damage. To ensure a stable climate inside the display cases, a low air exchange rate is maintained. Typically air exchange rates are often smaller than 0.1 d 1, which can result in rising concentrations of potential harmful immissions inside of the display cases due to emissions from materials. Especially high concentrations of organic acids, which can emit from e.g. sealing materials, can produce damage of cultural objects. In 2012 BAM introduced a procedure witch is called: BEMMA-Scheme (Bewertung von Emissionen aus Materialien für Museumsausstattungen) which stands for: “Assessment of Emissions from Materials for Museum Equipment”. Micro chambers are used for VOC emission tests of display case construction materials, e.g. textiles, plastics, sealing material, coatings and others. Each sampling procedure is carried out in duplicate. Emissions like formic acid, acetic acid, formaldehyde and oximes are excluded and the sum of emissions of VVOCs, VOCs and SVOCs is limited. For a positive assessment all listed criteria must be fulfilled; otherwise the display construction material fails the BEMMA scheme. The BEMMA scheme is not a guarantee for an emission free display case, but a necessary requirement for the choice of suitable materials for emission and immission reduced display cases.
Paragraphs 6 to 8 of the proposed amendment to the German Federal Soil Protection and Contaminated Sites Ordinance contain new requirements regarding the application of soil-like material outside of a rootable soil layer. For example, it is intended to enable reusing of soil-like materials containing regulated substances in concentrations between the single and double precautionary values (PV), provided that the limit values for the eluate are complied with. The aim of a running project (funding code UFOPLAN 3716 74 203 0, German Federal Environmental Agency) is to fill data deficits for soil-like materials which meet the above-mentioned criteria to promote circular economy and conservation of natural resources. Different soil-like materials of various origin (for example dredged material, banquet peeling material, urban and meadow soils) are considered with a special focus on PAHs. A major challenge in sample acquisition is the relatively narrow target range of the PAH content between 3 and 6 mg/kg dm considering a high measurement uncertainty at this concentration level.
The contents of PAHs, heavy metals and other inorganic elements in solid matter are determined following established standards. In addition, the soil-like materials are characterized concerning particle size, pH, conductivity, SOM, TOC and carbonate content. To determine the eluate concentration, column tests according to DIN 19528 and batch tests according to DIN 19529 at a liquid/solid ratio (L/S) of 2 l/kg and 10 l/kg are performed comparatively.
The results show that the new requirements of the planned amendment to the Federal Soil Protection and Contaminated Sites Ordinance certainly opens additional possibilities for reuse of soil-like materials. Even most soil-like materials within 2-3 x PV comply with the eluate value for PAH (0.2 μg/l) both in the batch test and in the column test at L/S 2 l/kg. Selected inorganic substances lead to similar evaluations. Therefore, the application of such soil-like materials outside of rootable soil layers would be possible. Previously, those materials were often used for landfill construction. In the future, a utilization in the adjacent environment by backfilling, recultivation, renaturation, composting or landscaping would be conceivable.
Draft standards for the determination of organic pollutants in the solid matter of environmental matrices such as sludge, treated biowaste and soil have been basically developed in the framework of the European standardization project HORIZONTAL. A research project financed by the German Federal Environment Agency was initiated to finalize some of these CEN standard drafts, since fully validated standard procedures are crucial for the evaluation of their reliability in the context of implementation in legislation on environmental health.
Approach: Appropriate test materials (< 2mm particle size) were prepared and homogenized from contaminated soils, sludge and treated biowaste containing polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), dioxins, furans and dioxin-like-PCB and served, along with reference solutions, as the basis for international interlaboratory comparisons. Performance data of three analytical standard procedures were obtained by the statistical evaluation of results received from 11 to 29 participants per test material.
Results: The overall variation coefficients of reproducibility (between-lab standard deviations) for the sum parameters were roughly between 10 and 35 %. The variation coefficients of repeatability (within-lab standard deviations) range between 3 % and 8 % and show no trend considering the substance groups or matrices.
The highest coefficients of reproducibility were found for the analysis of PAHs, which were between 26 and 35 %, depending on the matrix, whereas 7-17 % reproducibility was observed for toxicity equivalents (TEQ) comprising dioxins, furans and dl-PCB.
Conclusions: Overall, the results confirm that the procedures described in the Technical Specifications are fit for purpose for all three matrices and that the feasibility of the HORIZONTAL approach, to cover several matrices with one standard per analyte, was thereby proven.
Small-scale variations in mineral chemistry, textures, and platinum group element (PGE) mineralization were investigated in the Lower and Middle Group chromitite layers LG6, LG6a, MG1, MG2, and MG2 II from vertical drill core profiles at the Thaba mine in the northwestern limb of the Bushveld Complex. We present detailed geochemical profiles of chromite composition and chromite crystal size distribution curves to shed light on the processes of chromite accumulation and textural modification as well as mineralization. Multiple samples within each layer were assayed for PGE concentrations, and the respective platinum group mineral association was determined by mineral liberation analysis (MLA).
There is strong evidence for postcumulus changes in the chromitites. The crystal size distribution curves suggest that the primary chromite texture was coarsened by a combination of adcumulus growth and textural equilibration, while compaction of the crystal mush played only a minor role. Mineral compositions were also modified by postcumulus processes, but because of the very high modal amount of chromite and its local preservation in orthopyroxene oikocrysts, that phase retained much primary information. Vertical variations of chromite composition within chromitite layers and from one layer to another do not support the idea of chromite accumulation from crystal-rich slurries or crystal settling from a large magma chamber. Instead, we favor a successive buildup of chromitite layers by repeated injections of relatively thin layers of chromite-saturated magmas, with in situ crystallization occurring at the crystal mush-magma interface. The adcumulus growth of chromite grains to form massive chromitite required addition of Cr to the layers, which we attribute to downward percolation from the overlying magma.
The PGE concentrations are elevated in all chromitite layers compared to adjacent silicate rocks and show a systematic increase upward from LG6 (avg 807 ppb Ir + Ru + Rh + Pt + Pd + Au) to MG2 II (avg 2,062 ppb).
There are also significant internal variations in all layers, with enrichments at hanging and/or footwalls. The enriched nature of chromitites in PGEs compared to host pyroxenites is a General feature, independent of the layer thickness. The MLA results distinguish two principal groups of PGE mineral associations: the LG6, LG6, and MG1 are dominated by the malanite series, laurite, and PGE sulfarsenides, while the MG2 and MG2 II layers are characterized by laurite and PGE sulfides as well as Pt-Fe-Sn and PGE-Sb-Bi-Pb alloys. Differences in the PGE associations are attributed to postcumulus alteration of the MG2 and MG2 II layer, while the chromitites below, particularly LG6 and LG6a, contain a more pristine association.
Traceable and reliable chemical element analysis of aerosols by X-ray spectrometry was investigated using aerosol samples from field campaigns which have been measured in the GIXRF-beamline at BESSY.
The reference-free XRF approach allows for a traceable analysis of the mass deposition.
Traceable quantification by means of XRF can be transfered to benchtop instrumentation used in the laboratory Chemical and dimensional analysis of deposited aerosol allows for a comprehensive analysis of aerosols, e.g. for toxicity assessment and determination of the source The folowing elements could be identified and quantified in the field samples: Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Y, W, Pb.
Bacterial samples are typically freeze dried or cryo-prepared prior to XPS analysis to allow for measurements in ultra-high vacuum (UHV). The sample environment in the near-ambient pressure (NAP) XPS instrument EnviroESCA allows for measurements in up to 15 mbar water vapor, thus, sample preparation is no longer restricted to UHV-compatible techniques. For instance, biofilms grown in medium can be transferred directly from the medium to the measurements chamber, maintaining a humid environment throughout the measurements. Considering the complexity of bacterial samples, sample preparation must be carefully considered in order to obtain meaningful and reproducible results.
In this talk, various strategies for sample preparation of bacteria and biofilms for NAP-XPS measurements will be discussed. Model systems of planktonic bacteria, artificial biofilms resembling the exopolysaccharide matrix and biofilms have been characterised in various conditions. The stability and homogeneity of the samples was assessed by monitoring the C1s core level peak at different sample locations. The quality of the XPS-spectra is also influenced by the gas environment, which will be exemplified by core level spectra of P. Fluorescens acquired in air, water vapor and ultra-high vacuum.
Since the early 19th century microorganisms were studied on their capabilities of causing microbiologically influenced corrosion (MIC) of metals. The most studied ones are sulfate-reducing bacteria (SRB), but others can corrode metals as well, e.g. acid-producing bacteria or methanogenic archaea (MA). However, these studies were mostly focused on metals related to the petroleum industry but metals for other industries, e.g. dentistry, are also susceptible to corrosion. The inert Titanium (Ti) is often used as an implant material, but it is a base metal. The formation of a passivating oxide layer allows Ti to be corrosion resistant at normal conditions.
Nonetheless, scanning electron microscope images on dental implants from patients with acute peri-implantitis showed clear signs of corrosion. Currently, the corrosion mechanism of dental implants is unknown, but many indications suggest that oral microorganisms, including MA (Methanobrevibacter oralis) and SRB (Desulfomicrobium orale), could be involved.
To determine if MA or SRB can corrode Ti (pure Ti or Ti-6Al-4V alloy), corrosion rate, methane and sulfide concentrations were analyzed. Electrical potential measurements using in-house developed electrochemical cells indicated a potential change on Ti in the presence of a corrosive MA strain compared to an abiotic control.
Microbial composition comparison will be analyzed using samples from dental pockets of 150 infected patients by considering the quality of the implant and 50 healthy people by means of amplicon sequencing. Enrichments and isolation of pure cultures from the dentals samples are also examined for their corrosion behavior. Overall, this is the first study investigating the susceptibility of dental implant material to corrosion using human related MA.
The European building sector is moving towards more complex and high-tech building approaches. While focusing on energy efficiency, aspects e.g. occupant health, sustainability and life cycle costing are often neglected. This study highlights the potential of earthen plasters in combination with natural ventilation for low-tech solutions.
The EU funded project [H]house established the outstanding performance of earthen materials in light of hygrothermal and air purifying properties, which were further supported by experimental data from monitoring of naturally ventilated pilot buildings in Berlin. Additionally, [H]house demonstrated through LCC an increased cost efficiency of earth based low-tech solutions in comparison to conventional constructions relying on mechanical ventilation.
Microbially influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) which act upon the metal by the reactiveness of hydrogen sulfide, and by withdrawal of the available electrons in electrical contact with the metal. Methanogenic archaea can also cause MIC by directly withdrawing electrons from the iron surface for methanogenesis. However, the mechanistic details and kinetics of the overall process are poorly understood. Precipitation of siderite, a by-product of methanogenesis, (4Fe + 5HCO3 + 5H+ 4FeCO3 + CH4 + 3H2O) can lead to an insulating layer on the metal surface and lower the corrosion rate. Still, the extent of FeCO3 precipitation may be significantly influenced by environmental conditions such as pH and advective processes.
Microbiologically influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) in offshore industries, such as the oil and gas pipelines, due to the high concentrations of sulfate in the seawater. SRM act upon the metal by the reactiveness of hydrogen sulfide (HS-), and by withdrawal of the available electrons (Fe --> Fe2+ + 2e-; E° = -0.47 V) in electrical contact with the metal (EMIC). However, methanogenic archaea can also cause MIC. Because they do not produce HS-, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood.
To investigate the corrosion potential of methanogens, we studied the EMIC methanogenic strains isolated from marine sediments (Methanobacterium-affiliated strain IM1) and crude oil tanks (Methanococcus maripaludis Mic1c10), in an in-house developed flow-through cell to simulate a fluctuating environment. A co-culture of M. maripaludis and D. alaskensis was also established to study the effect of syntrophic growth on metal corrosion that may occur in industrial pipelines. Results indicate that the rates of iron corrosion due to coupled methanogenesis (up to 0.4 mm/yr) are higher to that caused by the marine SRM Desulfovibrio alaskensis (0.15 mm/yr). Surface analyses of the metal showed severe pitting with high methane production. Genomic analysis of the EMIC methanogen M. maripaludis Mic1c10 will provide an insight on the mechanisms of MIC. Such knowledge and deeper understanding also from an electrokinetic point of view may not only provide further models in microbial electrophysiology, but also contribute to mitigation strategies in MIC
Microbiologically influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) in offshore industries, such as the oil and gas pipelines, due to the high concentrations of sulfate in the seawater. SRM act upon the metal by the reactiveness of hydrogen sulfide (HS-), and by withdrawal of the available electrons (Fe --> Fe2+ + 2e-; E° = -0.47 V) in electrical contact with the metal (EMIC). However, methanogenic archaea can also cause MIC. Because they do not produce HS-, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood.
To investigate the corrosion potential of methanogens, we studied the EMIC methanogenic strains isolated from marine sediments (Methanobacterium-affiliated strain IM1) and crude oil tanks (Methanococcus maripaludis Mic1c10), in an in-house developed flow-through cell to simulate a fluctuating environment. A co-culture of M. maripaludis and D. alaskensis was also established to study the effect of syntrophic growth on metal corrosion that may occur in industrial pipelines. Results indicate that the rates of iron corrosion due to coupled methanogenesis (up to 0.4 mm/yr) are higher to that caused by the marine SRM Desulfovibrio alaskensis (0.15 mm/yr). Surface analyses of the metal showed severe pitting with high methane production. Genomic analysis of the EMIC methanogen M. maripaludis Mic1c10 will provide an insight on the mechanisms of MIC. Such knowledge and deeper understanding also from an electrokinetic point of view may not only provide further models in microbial electrophysiology, but also contribute to mitigation strategies in MIC
Microbiologically influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) in offshore industries, such as the oil and gas pipelines, due to the high concentrations of sulfate in the seawater. SRM act upon the metal by the reactiveness of hydrogen sulfide (HS-), and by withdrawal of the available electrons (Fe --> Fe2+ + 2e-; E° = -0.47 V) in electrical contact with the metal (EMIC). However, methanogenic archaea can also cause MIC. Because they do not produce HS-, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood.
To investigate the corrosion potential of methanogens, we studied the EMIC methanogenic strains isolated from marine sediments (Methanobacterium-affiliated strain IM1) and crude oil tanks (Methanococcus maripaludis Mic1c10), in an in-house developed flow-through cell to simulate a fluctuating environment. A co-culture of M. maripaludis and D. alaskensis was also established to study the effect of syntrophic growth on metal corrosion that may occur in industrial pipelines. Results indicate that the rates of iron corrosion due to coupled methanogenesis (up to 0.4 mm/yr) are higher to that caused by the marine SRM Desulfovibrio alaskensis (0.15 mm/yr). Surface analyses of the metal showed severe pitting with high methane production. Genomic analysis of the EMIC methanogen M. maripaludis Mic1c10 will provide an insight on the mechanisms of MIC. Such knowledge and deeper understanding also from an electrokinetic point of view may not only provide further models in microbial electrophysiology, but also contribute to mitigation strategies in MIC.
Microbiologically influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) in offshore industries, such as the oil and gas pipelines, due to the high concentrations of sulfate in the seawater. SRM act upon the metal by the reactiveness of hydrogen sulfide (HS-), and by withdrawal of the available electrons (Fe --> Fe2+ + 2e-; E° = -0.47 V) in electrical contact with the metal (EMIC). However, methanogenic archaea can also cause MIC. Because they do not produce HS-, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood.
To investigate the corrosion potential of methanogens, we studied the EMIC methanogenic strains isolated from marine sediments (Methanobacterium-affiliated strain IM1) and crude oil tanks (Methanococcus maripaludis Mic1c10), in an in-house developed flow-through cell to simulate a fluctuating environment. A co-culture of M. maripaludis and D. alaskensis was also established to study the effect of syntrophic growth on metal corrosion that may occur in industrial pipelines. Results indicate that the rates of iron corrosion due to coupled methanogenesis (up to 0.4 mm/yr) are higher to that caused by the marine SRM Desulfovibrio alaskensis (0.15 mm/yr). Surface analyses of the metal showed severe pitting with high methane production. Genomic analysis of the EMIC methanogen M. maripaludis Mic1c10 will provide an insight on the mechanisms of MIC. Such knowledge and deeper understanding also from an electrokinetic point of view may not only provide further models in microbial electrophysiology, but also contribute to mitigation strategies in MIC.zeige weniger
Microbiologically influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) in oil and gas facilities. SRM act upon the metal by the re-activeness of hydrogen sulfide (HS-), and by withdrawal of the available electrons in electrical contact with the metal (EMIC). Methanogenic archaea (MA) can also cause MIC (Mi-MIC). Several MAs were identified to be corrosive by using elemental iron as the sole electron donor for methanogenesis, including Methanobacterium-affliated IM1 and Methanococcus maripaludis Mic1c10. Currently, low corrosion rates were reported for MA, possibly due to the formation of siderite (4Fe + 5HCO3- + 5H+ ® 4FeCO3 + CH4 + 3H2O). Since MA do not produce HS-, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood.
To investigate the corrosion potential of MA, we studied the EMIC methanogenic strains (IM1 and Mic1c10) individually or part of a syntrophic co-culture with SRM. Corrosion studies were conducted using an in-house developed flow-through system to simulate fluctuating environmental conditions. Results indicate that the rates of iron corrosion by MA (up to 0.4 mm/yr) are higher to that caused by the marine SRM Desulfovibrio alaskensis (0.15 mm/yr) and the co-culture (0.1 mm/yr). Scanning electron microscopy (SEM) images of the metal incubated with MA showed severe pitting corrosion. Genomic analysis of the EMIC MA was conducted to provide an insight on the possible cellular mechanisms that could be involved. Furthermore, low concentrations of MA-targeting biocides will be applied to EMIC MA in static and flow conditions to gain insights for possible mitigation strategies. Such knowledge and deeper understanding also from an electrokinetic point of view may not only provide further models in microbial electrophysiology, but also contribute to mitigation strategies in MIC.
P recycling fertilizers are gaining increasing importance in our efforts to close nutrient cycles. An unsatisfactory performance of standard chemical extraction methods to assess the fertilizing effects of such products was reported. They demonstrated that DGT extractions of incubated soil/fertilizer mixtures were able to predict the fertilizing effects of the respective products more accurately. Since DGT works with soil/fertilizer mixtures, its interpretation is soil-dependent. Therefore, in order to facilitate its use as a tool to predict fertilizer performance, it needs to be standardized based on a standard substrate. This research aims to develop a standard substrate based on which evaluation categories for the DGT fertilizer extraction can be derived. The substrate composition should allow to vary the most important soil properties determining the plant availability of fertilizer P. It must also be reproducible at any time and any place. Substrate variants with varying proportions of quartz sand, a clay mineral and sphagnum peat were prepared and set to pH-levels 5.5 and 7 by addition of CaCO3. 7 variants were incubated with a set of test fertilizers (2 recycling fertilizers based on sewage sludge ash and 2 conventional mineral fertilizers) for 2 weeks. Substrate/fertilizer mixtures were then extracted with DGT and an ANOVA was performed to test if the DGT extraction was able to depict significant differences between fertilizers and substrate variants. An 8-week pot trial with ryegrass (3 cuts) was set up with the same substrate variants and test fertilizers. P uptake was determined to assess the fertilizing effect and correlated with the results of the DGT extractions. Statistically significant differences were found between DGT results for the various test fertilizers and substrate variants, indicating that DGT is able to differentiate between P solubility of fertilizers in relation to substrate quality. DGT results showed a strong relationship with P uptake, confirming that this method is suitable to predict the fertilizing effect of P fertilizers. Further optimization of substrate composition and tests with a wider variety of crops and fertilizer types are needed, before evaluation categories for DGT values can be derived.
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 compatible solute ectoine is a versatile protectant synthesized by many prokaryotes. It is used as an osmolyte helping microorganisms to maintain an osmotic equilibrium. In addition, ectoine acts as a stabilizer and protects proteins, membranes and whole cells against detrimental effects such as freezing and thawing, drying and high temperatures. Its protective effect is explained by the preferential exclusion model, which postulates that ectoine does not directly interact with biomolecules but is excluded from their surface. Interestingly, details on the interaction of ectoine with DNA are still unknown. Therefore, we studied the influence of ectoine on DNA and the mechanisms by which ectoine protects DNA against ionizing radiation. To emulate biological conditions, we used a sample holder comprising a silicon chip with a Si3N4 membrane, which allows for electron irradiation of DNA in aqueous solution. Analysis by atomic force microscopy revealed that without ectoine, DNA was damaged by irradiation with a dose of 1,7 +/-0,3 Gy. With ectoine, DNA remained undamaged, even after irradiation with 15 Gy. Simulations with dsDNA and ectoine in water revealed a preferential binding of the zwitterionic ectoine to the negatively charged DNA. According to the simulations, binding of ectoine will destabilize dsDNA. Destabilizing is probably caused by the transition of B-DNA to A-DNA and will reduce the DNA melting temperature, which was experimentally proven. The preferential binding provides a stable ectoine shell around DNA, which allows ectoine to reduce OH-radicals and electrons near the DNA and thereby mitigating the damaging effect of ionizing radiation.
The particle size distribution is considered the most relevant information for nanoscale property identification and material characterization. The current OECD test guideline on particle size and size distribution (TG 110) is not applicable to ‘nano-sized’ objects. In this project we thus develop a new OECD test guideline for the measurement of the size and size distribution of particles and fibers with at least one dimension in the nanoscale. A fiber is defined as an object having an aspect ratio of length/diameter l/d >3. The width and length of each fiber should be measured concurrently.
In order to measure the particle size distributions, many techniques are available. 9 methods for particles and 2 methods for fibres have been tested in a prevalidation study and appropriate methods will be compared in an interlaboratory round robin test starting in February 2019.
The new OECD test guideline will address the following four main steps in the determination of the length and width distributions of fibers: sample preparation, image acquisition, data evaluation and uncertainty analysis. As the sample preparation has to be optimized for each material, general quality criteria will be given in the protocol. For full visibility of a fiber the appropriate resolution has to be chosen. In the data evaluation the length and diameter of each fiber will be determined concurrently to allow for application of different regulatory definitions. The quality of the results critically depends on the sample preparation as well as the data evaluation. In this step the classification rules have to be formulated and followed accurately in order to optimize reproducibility of the method. The SOP will be validated in an international round robin test, which is planned for 2018/2019.
Without precaution, insects may cause serious damage to museum collections. Quarantine of potentially infested objects can be logistically challenging. Anoxia under controlled Nitrogen atmosphere is a most gentle but also time-consuming method to eradicate insect pests in all kinds of different materials. Treatment results are usually affected by duration, temperature, humidity and residual oxygen content. During a two-year research project, 34 relevant pest insect species of all developmental stages were tested in different materials (wood, paper, wool) to monitor treatment success and to determine optimum treatment parameters. Duration of treatment ranged from one to three weeks at temperatures of 20–27 °C. As expected, results showed significant differences in mortality among tested species. Highest tolerance of hypoxic conditions was found in elder larvae of Hylotrupes bajulus. Although this species is an unlikely museum pest, it may serve as an overall most tolerant reference. Anobiids and other wood boring beetles are more often an issue related to cultural heritage. A combination of three weeks exposure time at maximum 0.5% residual oxygen and 24 °C, alternatively 1%
residual oxygen and 27 °C are recommended for infested artefacts. Imbedding materials in general had no influence on mortality. This study was funded by Deutsche Bundesstiftung Umwelt (DBU).
Copper-based fungicides are routinely used for wood and plant protection, which can lead to an enrichment of copper-tolerant microbial communities in soil. To investigate the effect of such wood preservatives on the soil fungal and bacterial community compositions, five different vineyard and fruit-growing soil environments were evaluated using incubation studies over time. Pine sapwood specimens were impregnated with either water or different biocide treatment solutions containing a mixture of copper, triazoles, and quaternary ammonium compounds (CuTriQAC), a mixture of triazoles and quaternary ammonium compounds (TriQAC), or copper alone (Cu). Specimens were incubated in soil from each sample site for 8, 16, 24, and 32 weeks. The effects of preservative treatment on the modulus of elasticity (MOE) of the wood specimens and on the soil fungal as well as bacterial community composition at the soil-wood interface were assessed by quantitative PCR and amplicon sequencing of the fungal internal transcribed spacer (ITS) region and bacterial 16S rRNA gene. Specimens impregnated with CuTriQAC and Cu showed decreased MOE and reduced fungal and bacterial copy numbers over time compared to those impregnated with water and TriQAC. Fungal but not bacterial community composition was significantly affected by wood preservative treatment. The relative abundance of members of the family Trichocomaceae compared to other genera increased in the presence of the Cu and CuTriQAC treatments at three sites, suggesting these to be Cu-tolerant fungi. In conclusion, the copper-containing treatments resulted in marginally increased MOE, lowered microbial gene copy numbers compared to those in the TriQAC and water treatments, and thus enhanced wood protection against soil microbial wood degradation
In Denmark, increasing amounts of woody biomass are being used for the production of renewable energy, resulting in more wood ashes being generated. While these materials have been mainly landfilled, wood ashes may also be utilised for fertilizing and liming purposes on top of soils. Pre-treatments involving hardening or granulation may be carried out prior to soil application. In this study, two Danish wood ash samples were hardened and/or granulated. Lab-hardening induced rapid changes in the shape of the acid neutralisation capacity curve of the ashes. Up-flow column tests, assuming local equilibrium conditions, were employed to investigate the leaching from pre-treated ashes. Granules and loose ashes demonstrated similar leaching behaviours, indicating that similar geochemical processes were governing their leaching. In comparison with untreated fresh ashes, the hardened ashes demonstrated reduced leaching of Ca, Ba, Pb and Zn with concentration levels generally below or close to the analytical limits of quantification; to the contrary, the leaching of As, P, Sb, Si, V and Mg was enhanced in the hardened ashes. The release of alkalinity was reduced by hardening. In general, all granules were barely breakable by finger-pinching and they could withstand one month of continuous leaching, preserving their overall shape. The solubility of phosphorous in neutral ammonium citrate indicated that about 30–51% of the total P content in the ash samples was released, suggesting that the ashes could be potentially valuable as P-fertiliser if applied onto soil.
Social insects nesting in soil environments are in constant contact with entomopathogens and have evolved disease resistance mechanisms within a colony to prevent the occurrence and spread of infectious diseases. Among these mechanisms: mutual grooming reduces the cuticular load of pathogens, and burial of cadavers and cannibalism can prevent pathogens from replicating within the group. We explored how the rate and type of collective behavioural response is determined by stepwise infection dynamics operating at the level of the individual. Specifically, we infected the eastern subterranean termite Reticulitermes flavipes with different types of infectious particle and infection route of the entomopathogenic fungus Metarhizium anisopliae and recorded behavioural responses of nestmates to individuals at different times during the progression of infections. As expected, termites groomed conidia-exposed individuals significantly more than controls. Interestingly, grooming was significantly elevated after fungal germination than before, suggesting that pathogen growth cues act as strong stimulators of allogrooming. Conidia-exposed termites were cannibalized, but only after they became visibly ill. By contrast, termites did not groom blastospore-injected individuals more than controls at any time-point following infection. Instead, we found that blastospore-injected individuals were continually cannibalized at a low-level following injection with either viable or heat-killed blastospores, with a marked increase in cannibalism after termites injected with viable blastospores became visibly ill and were close to death. Together, these findings point to the importance of host condition as a cue for social hygienic behavior, and that the host itself appears to emit essential sickness cues that act as targets for its own sacrifice. This demonstrates that termites have independently evolved to both identify and destructively respond to sickness.
The termites are a derived eusocial lineage of otherwise non-social cockroaches. Understanding the proximal and ultimate drivers of this major evolutionary transition represents an important goal in biology. One outstanding question concerns the evolution of termite immunity, which is thought to have undergone broad-sweeping adaptations in order to enhance group-level immune protection. To understand the evolutionary origins of termite immunity, we conducted qualitative and quantitative transcriptome analyses along a gradient of sociality. Firstly, we aimed to identify large-scale genetic shifts in immune traits linked to eusociality by comparing immune gene repertoires in solitary and subsocial cockroaches and across a range of eusocial termite lineages. Secondly, we compared the responses of a solitary cockroach, a subsocial wood-roach and different castes of a lower termite species to a non-specific immune challenge, in order to understand how sociality may have influenced the evolution of immune gene regulation. Firstly, we found that termites have a broadly representative repertoire of canonical immune genes as compared to gregarious cockroaches and subsocial wood-roaches. Secondly, with respect to immune challenge, the solitary cockroach and the subsocial wood-roach displayed a similarly comprehensive induced response, while the termite response was considerably dampened by comparison and strongly influenced by caste; with reproductives displaying a generally higher constitutive level of immune-gene expression compared to sterile castes. In summary we did not find termite eusociality to be associated with significant changes in immune gene diversity, but rather to be linked with significant modifications to the regulation of immunity following the origin of division of labour.
Results suggest a reduction in immune gene repertoires in termites and possible complementary expression between termite castes. With comparative genomics we will investigate the evolution of gene families related to immunity, try to understand where reductions and expansions take place and relate these changes to shifts in sociality and ecology. The role of TEs in expansions and contractions of immune gene families will be investigated. For these analyses, we propose to generate high quality, highly contiguous genomes of species from different levels of sociality, covering all major termite families. With comparative transcriptomics we will investigate the expression of immune genes in different castes. Via network analyses we will identify pathways indicated in differential immunity between castes and between species of different sociality levels. We will investigate how these pathways have been rewired along the transitions to higher levels of sociality and how, intra-specifically, they change between castes.
A broad suite of immune adaptations have evolved in social insects which hold close parallels with the immune systems of multicellular individuals. However, comparatively little is known about the evolutionary origins of immunity in social insects. We tackle this by identifying immune genes from 18 cockroach and termite species, spanning a gradient of social lifestyles. Termites have undergone contractions of major immune gene families during the early origin of the group, particularly in antimicrobial effector and receptor proteins, followed by later re-expansions in some lineages. In a comparative gene expression analysis, we find that reproductive individuals of a termite invest more in innate immune regulation than other castes. When colonies encounter immune-challenged nestmates, gene expression responses are weak in reproductives but this pattern is reversed when colony members are immune-challenged individually, with reproductives eliciting a greater response to treatment than other castes. Finally, responses to immune challenge were more comprehensive in both subsocial and solitary cockroaches compared to termites, indicating a reduced overall ability to respond to infection in termites. Our study indicates that the emergence of termite sociality was associated with the evolution of a tapered yet caste-adapted immune system.
The Weimar research project has set the goal of placing style-critical research on Old Master drawings on a new, methodologically proven foundation. The starting point is the stock of Dutch drawings possessed by the Klassik Stiftung Weimar, whose extent (ca. 1,400 items) and character make it one of the most significant outside the Netherlands. The focus here is on drawings that were executed with red chalk. This drawing material has different functions - one of which is the use as a transmission material. The methodological approach is double: first, the scientific indexing of this stock. The foundations for this, along with classic analysis of style, are innovative material-scientific methods of investigation.
Laser Powder Bed Fusion (L-PBF) is a promising additive manufacturing (AM) technology for metal part production especially for complex and lightweight structures or functional designs. In L PBF processes several by-products including welding plume and its condensates, spatter and ejected powder are generated during laser exposure. Investigations of micro- and nano-sized by-products have received little attention in literature. This study focuses on the analysis of particle emissions in L PBF of 316L stainless steel using a scattered light aerosol spectrometer and a fast mobility particle sizer spectrometer during the process which allows for in-situ analysis of particle sizes in the range of 6 nm to 100 µm. A distinct correlation of emission signals to part position can be revealed. In addition, a significant influence of laser scanning vector directions on emission signals is presented. Furthermore, differing powder layer thicknesses can be recognised by deviations in emission signals.
Laser Powder Bed Fusion (L-PBF) is a promising additive manufacturing (AM) technology for metal part production especially for complex and lightweight structures or functional designs. In L PBF processes several by-products including welding plume and its condensates, spatter and ejected powder are generated during laser exposure. Investigations of micro- and nano-sized by-products have received little attention in literature. This study focuses on the analysis of particle emissions in L PBF of 316L stainless steel using a scattered light aerosol spectrometer and a fast mobility particle sizer spectrometer during the process which allows for in-situ analysis of particle sizes in the range of 6 nm to 100 µm. A distinct correlation of emission signals to part position can be revealed. In addition, a significant influence of laser scanning vector directions on emission signals is presented. Furthermore, differing powder layer thicknesses can be recognised by deviations in emission signals.
Wild bees are important pollinators for agricultural crops and solitary species such as Osmia bicornis are particularly suitable for pollination management. Wild bees share floral resources with managed honey bees and may be exposed to emerging infectious diseases. Although studies have explored the prevalence of pathogens in solitary wild bee species, data regarding the impact of pathogens on solitary bee health are lacking.
We carried out experiments examining whether the solitary bee species O. bicornis is susceptible to infection with the emerging pathogen The results obtained indicate that N. ceranae may be able to infect O. bicornis but its impact on host fitness is negligible: survival rates did not differ between Control and inoculated bees, although male survival was marginally lower after infection. To explore the possible field-relevance of our findings, we collected wild bees near an infected and a non-infected hive and showed that N. ceranae was shared between managed and wild bees, although only the in presence of infected honey bees.
The findings of the present study show that O. bicornis is susceptible to pathogen spillover and could act as a potential reservoir host for N. ceranae in pollinator networks. Additional studies on this species incorporating sublethal effects, multiple infections and other interacting stressors are warranted.
An approach to achieve 'zero leakage' is discussed with respect to experience in Germany, where strict regulations for landfill lining and capping Systems have been developed and issued because of large environmental Problems related to landfills that accumulated in the 1970s and 1980s. Using a thick, high-quality high-density Polyethylene (HDPE) geomembrane (GM) that is installed free of residual waves and wrinkles in intimate contact with a compacted clay liner or geosynthetic clay liner of very low permeability, by a qualified, experienced, well-equipped and properly third-party-controlled installer, and which is protected by heavy protection layers designed with respect to the long-term performance of the GM may result in a liner or capping system of practically no leakage. This is demonstrated by analysing results of measurements obtained from permanently installed leak-detection Systems in combination with HDPE GMs. The survey was based on 32 German landfills with 1.276.500 m² of installed GMs.
The earliest known recipes for iron gall inks include four basic ingredients: oak galls – pathological growths of oak leaves; metal salts – usually referred to as vitriol; a binder such as gum Arabic; and water. The final product differs in the elemental composition due to the multitude of recipes as well as differences within the composition of the ink’s ingredients. Nowadays, based on the qualitative and semi-quantitative evaluation of X-ray fluorescence data, it is possible to distinguish inks on the basis of the so-called fingerprint model. The first goal of our study was to determine to what extent the type of XRF spectrometer affects the quality of the ink evaluation. We tested two types of spectrometers, semi-stationary machines equipped with polycapillary focusing optics and a handheld spectrometer with a diaphragm collimator and a relatively big interaction spot.
The second goal was to address the issue of whether the ink composition might be affected by storage in a metal container. The presentation will discuss the role of the spectrometer type in the evaluation of a thin layer material such as ink.
We have also learned that the iron-gall ink composition might depend on the type of vessel in which ink was being stored.
The objective of this study is to find out, to what extent the geochemical characteristics of lapis lazuli can be utilized in respect to its provenance. A wide range of variables is taken into consideration depending on the quantity of samples analysed from a specific geological region and the methods applied. In order to provide evidence, a multi-technique analytical approach using µXRF, ESEM, PGAA and PIXE is applied to samples from the most famous deposits of lapis lazuli. Special elements determined as fingerprints are compared in relation to the forming conditions obvious in textural features. The results and statistical output allow a differentiation that enables an optimized local classification of the blue stone. An absolute requirement for all geo-tracing performed on blue colored cultural objects of unknown provenance is awareness of the limits of analysis. The possible sources of lapis lazuli are tested by analysing the blue pigment used as paint on murals and ink on manuscripts from the Silk Road.
The global rise of antibiotic resistance has made the proper use of disinfectants more important than ever. Their application in clinical l settings is an integral part of antibiotics stewardship by preventing the occurrence and spread of infections. However, improper use of disinfectants also harbours the risk for the evolution of tolerance and resistance to disinfectants, but also to antibiotics. It is therefore crucial to understand whether and how bacteria can survive chemical disinfection and which conditions facilitate the evolution of tolerance and resistance.
Here, we study the heterogeneity in the response of isogenic E. coli populations exposed to different levels of commonly used disinfectants. At concentrations below the minimal inhibitory concentration (MIC), we find that certain disinfectants induce prolonged lag times in individual cells, a phenotype that has been associated with persistence against antibiotics. At concentrations above the MIC, we find heterogeneous killing for a range of the tested substances. Interestingly, for the three cationic surfactants that were tested, we find kill kinetics revealing the presence of a tolerant subpopulation that can withstand disinfection longer than most of the population. We will present results from an ongoing evolution experiment in which we test the potential for evolution of population-wide tolerance and resistance through intermittent exposure to lethal doses of a cationic surfactant.
The presented Humboldt Codices are from the early colonial period of Mexico and originate from different localities
1. typical indigen colors and mixtures:
cochineal (red), indigo (blue and green), carbon (black),
mangle, zacatlaxcalli, organic (brown, yellow)- critical!
2. colonial influence:
iron gall ink for writing
3. single fragments belong together:
are cut (fragments IX-XII),
from Mizquahuala distributed (VII, XIII, XIV, [XV]) (VII, XIII in Mexico, XIV in Paris)
The collection Manuscripta Americana in Berlin consists of fragmented codices acquired by Alexander von Humboldt in Mexico. Some of these Humboldt Codices are published as hieroglyphic writings of the Aztecs in “Vues des Cordilleres et Monuments des Peuples indigènes de l’Amerique”. Starting from a special compilation of seven fragments on plate 36 in the “Atlas”, we investigated the corresponding original fragments using material analysis in order to clarify their historical relations. The analyses were carried out with X-ray fluorescence analysis, VIS spectroscopy, and infrared spectroscopy in diffuse reflection and revealed typical indigenous colors like cochineal, indigo, and organic yellows (e.g. mangrove and zacatlaxcalli). Four fragments under investigation show exactly the same material and thus must once have belonged together in one compendium. An additional manuscript from Mizquiahuala also shown on plate 36 can be matched to another one that is not published in the “Atlas”.
The objective of this study is to find out, to what extent the geochemical characteristics of lapis lazuli can be utilized in respect to its provenance. A wide range of variables is taken into consideration depending on the quantity of samples analysed from a specific geological region and the methods applied. In order to provide evidence, a multi-technique analytical approach using µXRF, ESEM, PGAA and PIXE is applied to samples from the most famous deposits of lapis lazuli. Special elements determined as fingerprints are compared in relation to the forming conditions obvious in textural features. The results and statistical output allow a differentiation that enables an optimized local classification of the blue stone. An absolute requirement for all geo-tracing performed on blue colored cultural objects of unknown provenance is awareness of the limits of analysis. The possible sources of lapis lazuli are tested by analysing the blue pigment used as paint on murals and ink on manuscripts from the Silk Road.
Environmental sustainability and –stability of materials concerning the migration of pollutants
(2019)
In addition to previously reported results on the accelerated weathering of polystyrene samples (PS) containing 1 wt. % hexabromocyclododecane (HBCD), we present the first results of our investigations of polypropylene samples (PP) containing 0.1 wt. % BDE-209. All studied polymer samples were exposed to a defined weathering schedule in a climate chamber in accordance to regulation EN ISO 4892-3:2006. For the determination of BDE-209 in the collected raining water the samples were prepared in accordance to a validated protocol. Before the analyses each sample was spiked with isotopically labeled BDE-209. Subsequently the samples were extracted with isooctane. The obtained extracts were concentrated, and the resulting solutions were analyzed by GC/MS. Additionally, the total bromine content was monitored for the weathered and untreated samples using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and X-ray fluorescence analysis (XRF) as a non-destructive and rapid method. In general, the resulting data from the accelerated weathering will be compared to those from the natural weathering experiments. Here, the surfaces of the test pieces were analyzed by LA-ICP-MS and XRF as well. Moreover, soil bed tests were conducted in a well characterized model soil. This soil (boulder-clay, sand with 12 % loam, particle size in total 0.2-4 mm) is filled in a free-draining basin inside of an air-conditioned cellar. In this manner, TOC, water capacity and humidity are recorded parameters. To induce a leaching process from the samples by the raining water, the target water content is calculated to 8%. The actual humidity is measured by a tensiometer, assuring the duration of the raining period. A defined humidity is a fundamental parameter for a biological activity in the soil. The test polymers were placed up to the half in the soil. Microbial activity of the soil is monitored by a reference polymer (polyurethane) and should induce the release of HBCD and BDE-209 out of the test materials. These released analytes will be captured by passive samplers (silicone tubes) placed in a distinct distance to the polymer samples in the soil. The soil bed experiments are complementary to the weathering experiments due to the biological activity in the soil.
Introduction: Biofilms are regarded as a common cause of chronic infections on medical devices. Preventive and therapeutic strategies against biofilm infections commonly involve applications of multiple antimicrobial substances: antimicrobial coatings on the implanted biomaterials in combination with systemically administered antibiotics. While this practice of combination therapy harbours the risk of developing cross-resistance, it might also provide the possibility to implement specific antimicrobial-antibiotic combinations (AACs) that can slow down the selection of antibiotic resistant strains.
Hypothesis and aims: Specific AACs can exert combinatorial effects on the growth of susceptible and antibiotic-resistant Pseudomonas aeruginosa that either suppress or increase their individual effects.
Our aim is to identify AACs with antagonistic or synergistic effects on pseudomonal biofilms and to understand their impact on selection of resistant strains. Specifically, we want to identify AACs that select for and against antibiotic resistance during biofilm formation.
Methodology: We screened for AACs that cause antagonistic or synergistic effects on planktonic P. aeruginosa.
To study the effect of antimicrobial-antibiotic exposure on resistance selection in bacterial biofilms, we will grow resistant and sensitive strains on PDMS surfaces with and without antimicrobial coatings and expose them to antibiotics.
Results: Several combinations with synergistic or antagonistic interaction on the growth rate of P. aeruginosa were detected. We observed a strong antagonism when combining the antimicrobial substance chlorhexidine with the carbapenem drug meropenem. A meropenem-resistant mutant showed a selection advantage in low concentrations of chlorhexidine combined with a sub-inhibitory concentration of meropenem over the wild-type. No antagonistic effect was observed for the same combination when E. coli was exposed to chlorhexidine and meropenem, suggesting a non-chemical basis for the observed effect on P. aeruginosa.
Conclusion: Gaining a better understanding about resistance selection during biofilm formation on biomedical surfaces will enable us to mitigate against biofilm-associated antimicrobial resistance.
Uninvited and Welcomed Guests in Museums – Biological management of
clothes moths and woodworms
(2019)
In museums and historic houses clothes, moths (Tineola bisselliella, Tinea pellionella) and the furniture beetle (Anobium punctatum) are the most economically important pests on textiles or wooden artifacts, respectively. Their management is essential to protect cultural ethnological heritage and natural history collections for future generations.
Pest management strategies have changed over time. Today, intensive knowledge on pest biology and overall material science are key cornerstones in IPM concepts - also for the museum environment. The important first steps for sustainable pest management are risk assessment, early pest detection and identification of pathways of infestation. These steps are followed by physical and biological means of control, which have lately gained more importance than applying biocides.
Several potentially effective biological enemies of clothes moths and woodworm have been known for a long time, but their promotion for pest control in museums and historic houses is just beginning.
This short review summarizes current concepts of pest life cycle interruption by applying good quarantine and very specific biological measures. The lessons learned from recent faunistic surveys, life-history studies as well as behavioral observations of parasitoids and predators of clothes moths and woodworm may supplement the pest management tool box. The need for further research in this field is addressed.
Mechanisms of olivine dissolution by rock-inhabiting fungi explored using magnesium stable isotopes
(2019)
To unravel the dissolution mechanisms of olivine by a rock-inhabiting fungus we determined the stable isotope ratios of Mg on solutions released in a laboratory experiment. We found that in the presence of the fungus Knufia petricola the olivine dissolution rates were about seven-fold higher (1.04×10−15 mol cm−2 s−1) than those in the abiotic experiments (1.43×10−16 mol cm−2 s−1) conducted under the same experimental condition (pH 6, 25 °C, 94 days). Measured element concentrations and Mg isotope ratios in the supernatant solutions in both the biotic and the abiotic experiment followed a dissolution trend in the initial phase of the experiment, characterized by non-stoichiometric release of Mg and Si and preferential release of 24Mg over 26Mg. In a later phase, the data indicates stoichiometric release of Mg and Si, as well as isotopically congruent Mg release. We Attribute the initial non-stoichiometric phase to the rapid replacement of Mg2+ in the olivine with H+ along with simultaneous polymerization of Si tetrahedra, resulting in high dissolution rates, and the stoichiometric phase to be influenced by the accumulation of a Si-rich amorphous layer that slowed olivine dissolution. We attribute the accelerated dissolution of olivine during the biotic experiment to physical attachment of K. petricola to the Si-richamorphous layer of olivine which potentially results in ist direct exposure to protons released by the fungal cells. These additional protons can diffuse through the Si-rich amorphous layer into the crystalline olivine. Our results also indicate the ability of K. petricola to dissolve Fe precipitates in the Si-rich amorphous layer either by protonation, or by Fe(III) chelation with siderophores. Such dissolution of Fe precipitates increases the porosity of the Si-rich amorphous layer and hence enhances olivine dissolution. The acceleration of mineral dissolution in the presence of a rock-dissolving fungus further suggests that its presence in surficial CO2 sequestration plants may aid to accelerate CO2 binding.
A reliable analysis of aerosol particle is curial for enforcing EU air quality regulations to protect human health, and for research on climate change effects [1]. Although metrics such as PM10 and PM2.5 are currently in use, the level of uncertainty of aerosol metrics is too high and the traceability is insufficient. Within the AEROMET project [2] procedures are developed aiming at reducing the uncertainties of particle mass, size, and number concentration measurements including the characterization of regulated components in airborne particles. Here, we present an approach how to improve the uncertainties of the particle mass by mobile total reflection x-ray fluorescence (TXRF) analysis. The combination of TXRF and aerosols sampling techniques supported by reference-free synchrotron radiation-based XRF enables a quantitative real-time analysis of particle mass. During in-field campaigns, the procedure was tested, monitoring the size dependent mass concentrations of specific elements in ambient aerosols under dynamic conditions. This approach allows a direct time and size-resolved analysis without laborious digestion steps and a reduced risk of contamination.
Aerosol particles were sampled in a 13-stage DLPI impactor on acrylic discs. TXRF analysis was performed on-site with the transportable spectrometer S2 PICOFOX (Bruker Nano GmbH). The TXRF quantification was based on internal standardization. At moderate air pollution levels (PM10 20 µg/m³) sampling times of less than 2 hours were enough to detect elements in different particle size bins. The on-site approach and the high sensitivity of TXRF enables the observation of rather quick changes in the quantity and distribution of elements in an ambient aerosol on the day of sampling. The analysis of the morning and afternoon sampling shifts reveals the occurrence of the elements Fe, Ca and Si in different size bins as well as their temporal change in respective mass concentrations over the day while the distributions of several other elements remain unchanged.
While studying the history of inks, division 4.5 of the BAM (Bundesanstalt für Materialforschung und Prüfung) together with the Centre for the Study of Manuscript Cultures in Hamburg has developed a protocol for ink analysis. It consists of a primary screening to determine the type of the ink, and a subsequent in-depth analysis using several spectroscopic techniques. One of them, X-ray Fluorescence (XRF) aims primarily at establishing the fingerprints of inks containing metals, making it possible to distinguish among different inks.
Our research aims primarily at recreating a socio-geographic history of inks, parchment, and papyrus and includes the comparative analysis of the writing materials of the Dead Sea Scrolls, ink and papyrus in Ancient and Hellenistic Egypt, and inks in documents from various contemporary medieval communities in Fustat (first nucleus of Cairo) as well as other medieval Jewish and Armenian communities.
The presentation shows the panorama of historic inks and our attempt to follow up the transition of the inks from those based on soot to the iron-gall inks commonly used in the Middle Age.
Our study is dedicated to non-destructive characterization of the support and the inks of the DSS.
To that aim we use micro-XRF, 3D- SY-XRF, different IR methods including synchrotron radiation based reflectance spectroscopy, optical and electron microscopy.
The lecture discusses advantages and the shortcomings of the non-destructive testing approach.
Our research aims primarily at recreating a socio-geographic history of inks, parchment, and papyrus and includes the comparative analysis of the writing materials of the Dead Sea Scrolls, ink and papyrus in Ancient and Hellenistic Egypt, and inks in documents from various contemporary medieval communities in Fustat (first nucleus of Cairo) as well as other medieval Jewish and Armenian communities.
The presentation shows the panorama of historic inks and our attempt to follow up the transition of the inks from those based on soot to the iron-gall inks commonly used in the Middle Age.
While studying the socio-geographic history of inks, division 4.5 of the Bundesanstalt für Materialforschung und Prüfung (BAM) together with the Centre for the Study of Manuscript Cultures (CSMC) in Hamburg has developed a non-invasive protocol for ink analysis. It consists of a primary reflectographic screening to determine the type of the ink (soot, tannin or iron-gall) and a subsequent in-depth analysis using several spectroscopic techniques: X-ray fluorescence (XRF), Infrared and Raman spectroscopies. The first of them, XRF elemental analysis aims at establishing the unique fingerprints of inks containing metals or trace elements in carbon inks. In addition, we use Raman analysis to identify so-called mixed inks, an ink category that received little attention so far. Finally, with the help of IR spectroscopy we obtain information about the ink binders.
The evolution and socio-geographic distribution of writing inks from Late Antiquity to the Middle Ages are one of the foci of our investigative work at the Bundesanstalt für Materialforschung und -prüfung (BAM) in Berlin and the Centre for the Study of Manuscript Cultures, Hamburg University.
This presentation will examine the inks used by Jews in the in different geographical zones try to correlate the results of the material analysis with written records and existing traditions. We will compare the inks proposed by Maimonides, who lived in 12th-century Egypt, with the considerations of Rashi, who lived in 11th-century northern France, and see that they both advocated use of the inks commonly known and produced in their respective regions. It is Maimonides who proposes to add tannins to the soot inks, but rejects the metallic salt, both of which were practices that were well attested in contemporary Arabic recipes for making ink. In contrast, Rashi was favourable to employing the plant inks in use in contemporary Northern Europe.
Natural sciences play auxiliary role in the studies of manuscripts. The success of their contribution depends strongly on the formulation of the question and the choice of the methods to obtain the requested answer. Therefore, one should try to go beyond the understanding of the basic principles of the scientific analysis.
We will start with a glance at the basic principles of the techniques used in the material science for determination of the elemental composition (X-ray emission) and molecular composition (FTIR & Raman). We will move then to the bench and mobile equipment commonly used in the field of cultural heritage. At the end we will choose a question to be answered and design an ideal experiment that will be modified according to the limitations dictated by on-site conditions.
In the ateliers in the afternoon we will
a) compare two XRF devices that differ in their spatial resolution;
b) use a high resolution microscope (Keyence) to obtain a close look at writing surfaces and materials;
c) we will learn to determine the type of the inks with the help of another microscope (DinoLite AD413T-12V), a usb microscope with visible, UV and NIR illumination;
d) we will learn to use FTIR-ATR device for determination of the type of the writing surface;
e) We will use mobile Raman device for identification of pigments.
Parchment
(2019)
This lecture will present history of parchment based on written sources and chemical examination of antique, medieval and modern parchment.
Our studies of the Dead Sea Scrolls writing surfaces show that they can be divided roughly into three groups: leather, parchments of a light tint, and those of various shades of brown. The latter ones are invariably tanned, whereas the middle group is characterized by the presence of various inorganic salts. Some of the pale parchments, among them the Temple Scroll (11Q19), are remarkably similar to medieval European parchment. Therefore we have formulated the working theory that in the Judaea of the Hellenistic period two different parchment-making traditions existed side by side: an ‘eastern’ one (represented by the tanned parchments of Qumran, closely resembling Aramaic documents from the fifth century BC, and a ‘western’ one (represented by the untanned/lightly tanned ones similar to early Christian Greek parchments).
This division has found support during our studies of the Geniza fragments, in which Babylonian and Palestinian traditions seem to follow the “eastern” and “western” technologies, respectively.
Inks and pigments
(2019)
The writing materials used in various cultures and epochs can be divided into two groups. The first comprises materials that write themselves, producing script by rubbing their own material off onto the writing surface. It includes charcoal, graphite, chalk, raddle, and metal styluses. Depending on the material and consistency, these are cut or pressed to make styluses and then used for writing.
The second group comprises all coloring liquids that are applied to the writing surface with a quill, pen, or printing block. It includes inks made from dye solutions (for example, tannin inks) and those made from pigment dispersions (for example, sepia, soot, and bister inks). The latter are sometimes also rubbed as pastes into letters incised into the writing surface, where they increase visual contrast.
Due to the variety of recipes and the natural origin of raw materials, there is a wide range of different components and impurities in writing materials.
Soluble inks (Tinten)
Soluble inks are based mainly on dyes forming a water solution. Colored inks were manufactured with different plant or insect dyes (e.g. Brazil wood, kermes). To stabilize the volatile material, the dyes were mixed with a mordant (e.g., alum).
Brown plant inks – best-known as blackthorn or Theophilus’ inks – are usually produced from the blackthorn bark and wine. In the early European Middle Ages, inks of this kind were widely used in the production of manuscripts in monasteries. Usually, they are light brown, so sometimes small amounts of iron sulfate were added, which led to what was called an “imperfect” iron gall ink. The difference between “classic” iron gall ink and such imperfect ink is therefore not clear: the distinction is not possible, especially with the naked eye.
Dispersion inks (Tuschen)
According to its generic recipe, one of the oldest black writing materials is produced by mixing soot with a binder dissolved in a small amount of water. Thus, along with soot, binders such as gum arabic (ancient Egypt) or animal glue (China) are among the main components of soot inks. From Pliny’s detailed account of the manufacture of various soot-based inks, we learn that, despite its seeming simplicity, producing pure soot of high quality was not an easy task in Antiquity. Therefore, we expect to find various detectable additives that might be indicative of the time and place of production. One such carbon ink requires the addition of copper sulfate . The experimental discovery of this ink in 1990 led to a misleading expression “metal ink” that is sometimes found in the literature.
Colored dispersion inks based on pigments such as orpiment, cinnabar, or azurite have been known since Antiquity. Natural or artificially produced minerals are finely ground and dispersed in a binding medium. As in soot inks, water-soluble binders such as gum arabic or egg white were used.
Iron gall ink (Eisengallustinten)
Iron gall inks are a borderline case between these two groups. They are produced from four basic ingredients: galls, vitriol as the main source of iron, gum arabic as a binding media, and an aqueous medium such as wine, beer, or vinegar. By mixing gallic acid with iron sulfate, a water-soluble ferrous gallate complex is formed; this product belongs to the type “soluble inks”. Due to its solubility, the ink penetrates the writing support’s surface, making it difficult to erase. Exposure to oxygen leads to the formation of insoluble black ferric gallate pigment, i.e., “dispersion ink”.
Natural vitriol consists of a varying mixture of metal sulfates. Since for ink making it was obtained from different mines and by various techniques, inks contain many other metals, like copper, aluminum, zinc, and manganese, in addition to the iron sulfate. These metals do not contribute to color formation in the ink solution, but possibly change the chemical properties of the inks.
Our experimental knowledge about the inks of antiquity and late antiquity rarely goes beyond their visual description. In rare cases, inks typology has been determined by means of microscopy and reflectography, i.e. using their physical and optical properties, respectively. Since carbon, plant and iron gall inks belong to different classes of compounds they could be easily distinguished had only pure inks been used. Even these crude observations suggest that the inks used differed greatly in their composition.
Reconstruction of the ink recipes with the help of advanced non-destructive analytical techniques could serve as a powerful accessory for in the studies of ancient papyri.
The proposed paper will present a short survey of the methods of material analysis and the challenges offered by ancient inks. The examples of the ink studies from the collections of the Israel Museum in Jerusalem and Egyptian Museum in Berlin will conclude the paper.
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.
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.
OECD test guideline on particle size and size distribution: Comparability of measurement results
(2019)
OECD-Prüfrichtlinien werden weltweit für regulatorische Zwecke angewandt, da sie eine harmonisierte und über internationale Ringversuche validierte Vorschrift zur Analyse vorgeben. Die bestehende Prüfrichtlinie TG 110 zur Größencharakterisierung von Partikeln und Fasern ist für viele Methoden und Materialklassen nicht geeignet, weswegen es Bedarf an einer Neuentwicklung gibt. Im Fokus der neuen TG steht die reproduzierbare und vergleichbare Anwendung von Methoden zur Bestimmung von Partikelgröße sowie Größenverteilung annährend sphärischer und faserförmiger Nanomaterialien im Bereich 1-1000 nm. Berücksichtigt werden die häufig angewandten Methoden zur Größencharakterisierung mit ihren unterschiedlichen physikalisch-technischen Limitierungen und die Bestimmung unterschiedlicher Durchmesser (hydrodynamischer, Feret…). Weiterhin sind materialspezifische Einflüsse durch die Partikel sowie das Messmedium zu berücksichtigen. Jede der Methoden soll unter Berücksichtigung von ISO-Standards und den materialspezifischen Limitierungen in der neuen Prüfrichtlinie beschrieben und über einen Ringversuch validiert werden.
Question:
Biocides are in contact with soils through direct application and passive leaching from protected materials. Consequently, soil microorganisms are exposed to toxic biocides even though they are not their primary targets. Soil is a large reservoir of microbial diversity and has been hypothesized to be a crucial factor for the evolution and spread of antimicrobial resistance. Currently, there is little knowledge on how biocides used to protect materials affect the evolution and spread of resistance. Thus, our aim is to investigate the risk for the evolution of biocide resistance and cross-resistance to antibiotics. In addition, we aim to elucidate the affect of biocides on the spread of resistance via horizontal gene transfer (HGT).
Methods:
In laboratory evolution experiments we culture selected model soil microorganism with representative biocides followed by antibiotic cross-resistance determination and genome sequencing. Moreover, we investigate if the selected biocides affect the HGT frequency of plasmids that carry resistance genes among soil microorganism and the consequences for survival of the affected populations.
Results:
Our initial results show only small increases of biocide resistance during serial transfers in the presence of biocides. One reason for this might be the narrow selective window for biocide resistance due to steep dose-response relationships. Furthermore, we will present results from ongoing experiments on the effects of material preservatives on HGT frequencies facilitating microbial community adaptation to stress.
Conclusions:
The results will enable future risk assessment regarding resistance evolution for biocides used as material preservatives.
Question:
Biocides are in contact with soils through direct application and passive leaching from protected materials. Consequently, soil microorganisms are exposed to toxic biocides even though they are not their primary targets. Soil is a large reservoir of microbial diversity and has been hypothesized to be a crucial factor for the evolution and spread of antimicrobial resistance. Currently, there is little knowledge on how biocides used to protect materials affect the evolution and spread of resistance. Thus, our aim is to investigate the risk for the evolution of biocide resistance and cross-resistance to antibiotics. In addition, we aim to elucidate the affect of biocides on the spread of resistance via horizontal gene transfer (HGT).
Methods:
In laboratory evolution experiments we culture selected model soil microorganism with representative biocides followed by antibiotic cross-resistance determination and genome sequencing. Moreover, we investigate if the selected biocides affect the HGT frequency of plasmids that carry resistance genes among soil microorganism and the consequences for survival of the affected populations.
Results:
Our initial results show only small increases of biocide resistance during serial transfers in the presence of biocides. One reason for this might be the narrow selective window for biocide resistance due to steep dose-response relationships. Furthermore, we will present results from ongoing experiments on the effects of material preservatives on HGT frequencies facilitating microbial community adaptation to stress.
Conclusions:
The results will enable future risk assessment regarding resistance evolution for biocides used as material preservatives.
Questions:
Biocides are in contact with soils through direct application and passive leaching from protected materials. Consequently, soil microorganisms are exposed to toxic biocides even though they are not their primary targets. Soil is a large reservoir of microbial diversity and has been hypothesized to be a crucial factor for the evolution and spread of antimicrobial resistance. Currently, there is little knowledge on how biocides used to protect materials affect the evolution and spread of resistance. Thus, our aim is to investigate the risk for the evolution of biocide resistance and cross-resistance to antibiotics. In addition, we aim to elucidate the affect of biocides on the spread of resistance via horizontal gene transfer (HGT).
Methods:
In laboratory evolution experiments we culture selected model soil microorganism with representative biocides followed by antibiotic cross-resistance determination and genome sequencing. Moreover, we investigate if the selected biocides affect the HGT frequency of plasmids that carry resistance genes among soil microorganism and the consequences for survival of the affected populations.
Results:
Our initial results show only small increases of biocide resistance during serial transfers in the presence of biocides. One reason for this might be the narrow selective window for biocide resistance due to steep dose-response relationships. Furthermore, we will present results from ongoing experiments on the effects of material preservatives on HGT frequencies facilitating microbial community adaptation to stress.
Conclusions:
The results will enable future risk assessment regarding resistance evolution for biocides used as material preservatives.
Tricalcium-silicate (C3S) or Alite is the most important mineral in Portland cement. Since pure tricalcium-silicate is only stable above temperatures of 1250 °C, its decomposition has to be prevented technically by fast cooling after the sintering process. At room temperature, the decomposition velocity is very slow so that metastable tricalcium-silicate is obtained.
Although the mechanisms of clinker phase formation during burning process of Portland cement in a rotary kiln were solved and improved over the years, in view of possible economic and ecological benefits current projects aim to produce clinker phases from metallurgical slags. Recent studies discovered that the mineral phase which remained after a reducing treatment and separation of formed metallic iron from molten Linz-Donawitz (LD-) slags contained about 60 wt.% Alite despite it was cooled slowly. Because the results could be verified using slags from different origins and varying cooling velocities a chemical stabilisation of the Alite can be assumed. First tests in mortars indicate that workability, hardening and solid state properties are comparable with an ordinary Portland cement. An application of the observed phenomenon in cement production requires enhanced knowledge about formation and stabilisation conditions of Alite during crystallisation from melts in contrast to the sintering reactions in conventional Portland cement production. Therefore, this study focuses on the stabilisation mechanisms of Alite in consolidating melts. Samples from different melting experiments are analysed to determine stabilising factors.
Question:
One cornerstone to prevent the spread of bacteria in clinical and industrial settings is the application of biocides including disinfectants and preservatives. However, bacteria can evolve resistance to biocides, which in turn can confer cross-resistance to antibiotics. Additionally, clonal bacterial populations can display phenotypic heterogeneity with respect to the tolerance of antibiotic stress leading to a prolonged survival of a sub-population; this phenomenon is termed persistence. Persistence to antibiotics is an evolvable trait and can serve as a stepping stone for the evolution of genetically encoded resistance. Until now, there is a lack of systematic studies that investigate if bacterial populations establish persister subpopulations that tolerate disinfectant stress longer than most of the population. Our objective is to investigate if persistence is a bacterial survival strategy against biocides. Furthermore, we investigate the mechanisms of biocide persistence and if persistence can evolve in the face of fluctuating exposure to biocides. Lastly, we test if the evolved mechanisms of biocide tolerance lead to biocide resistance and if they confer cross-tolerance and cross-resistance against antibiotics.
Methods:
We use time-kill assays in the presence of biocides and experimental evolution combined to whole-genome sequencing in the model organism E. coli.
Results:
We find persister sub-populations against chlorhexidine and quaternary ammonium compounds, but not to alcohols, aldehydes and oxidative compounds. We will present the relationship of mechanisms known to underlie antibiotic persister formation to the formation of persisters against biocides. In addition, we will present data from an ongoing evolution experiment for persistence against biocides.
Conclusion
There is a link between antibiotic and biocide persistence with possible implications for antibiotic resistance evolution and spread.
A fundamental question in ecology is how biodiversity affects ecosystem function. Biodiversity is commonly estimated based on genetic variation. We investigated a new approach that defines and measures biodiversity in complex microbial communities. We used the variation in multiple functionally-relevant, phenotypic traits measured in parallel in single cells as a metric for microbial phenotypic diversity. We studied phenotypic diversity and ecosystem functioning throughout different photosynthetic layers dominated by divergent microbial communities in the gradient of Lago di Cadagno. We determined genetic diversity by 16S and 18S amplicon sequencing and bulk ecosystem functioning (photosynthesis). In addition, we determined phenotypic diversity using single-cell technologies such as nanometer-scale secondary ion mass spectrometry (NanoSIMS) correlated with confocal laser scanning microscopy (CLSM) and scanning flow-cytometry. We measured functional trait variation between individuals in 13CO2 fixation, 15NH4+ uptake, and variation in physio-morphological cell traits, such as cell size, shape, and auto-fluorescence for various pigments related to photosynthesis. We used the distances between individuals in a multidimensional trait space to derive phenotypic trait-based diversity indices, such as trait richness, trait evenness, and trait divergence. We find that phenotypic trait divergence associates with ecosystem functioning, whereas genetic diversity does not. Including activity-based, single-cell phenotypic measurements with NanoSIMS provided an additional accuracy to the trait-based diversity assessment and allowed us to formulate hypotheses on the mechanisms that shape the correlation between phenotypic diversity and eco-system function. Together, our results show that phenotypic diversity is a meaningful concept to measure microbial biodiversity and associate it with ecosystem functioning.
A fundamental question in ecology is how biodiversity affects ecosystem function. Biodiversity is commonly estimated based on genetic variation. We investigated a new approach that defines and measures biodiversity in complex microbial communities. We used the variation in multiple functionally-relevant, phenotypic traits measured in parallel in single cells as a metric for microbial phenotypic diversity. We studied phenotypic diversity and ecosystem functioning throughout different photosynthetic layers dominated by divergent microbial communities in the gradient of Lago di Cadagno. We determined genetic diversity by 16S and 18S amplicon sequencing and bulk ecosystem functioning (photosynthesis). In addition, we determined phenotypic diversity using single-cell technologies such as nanometer-scale secondary ion mass spectrometry (NanoSIMS) correlated with confocal laser scanning microscopy (CLSM) and scanning flow-cytometry. We measured functional trait variation between individuals in 13CO2 fixation, 15NH4+ uptake, and variation in physio-morphological cell traits, such as cell size, shape, and auto-fluorescence for various pigments related to photosynthesis. We used the distances between individuals in a multidimensional trait space to derive phenotypic trait-based diversity indices, such as trait richness, trait evenness, and trait divergence. We find that phenotypic trait divergence associates with ecosystem functioning, whereas genetic diversity does not. Including activity-based, single-cell phenotypic measurements with NanoSIMS provided an additional accuracy to the trait-based diversity assessment and allowed us to formulate hypotheses on the mechanisms that shape the correlation between phenotypic diversity and eco-system function. Together, our results show that phenotypic diversity is a meaningful concept to measure microbial biodiversity and associate it with ecosystem functioning.
Background:
One cornerstone to prevent the spread of antibiotic resistant bacteria in clinical settings is the application of disinfectants. However, bacteria can evolve resistance to disinfectants, which in turn can confer cross-resistance to antibiotics. Additionally, clonal bacterial populations can display phenotypic heterogeneity with respect to the tolerance of antibiotic stress leading to a prolonged survival of a sub-population; this phenomenon is termed persistence. Persistence to antibiotics is an evolvable trait and can serve as a stepping stone for the evolution of genetically encoded resistance. Until now, there is a lack of systematic studies that investigate if bacterial populations establish persister subpopulations that tolerate disinfectant stress longer than most of the population.
Objectives:
Our objective is to investigate if persistence is a bacterial survival strategy against disinfectants. Furthermore, we investigate the mechanisms of disinfectant persistence and if persistence can evolve in the face of fluctuating exposure to disinfectants. Lastly, we test if the evolved mechanisms of disinfectant tolerance lead to disinfectant resistance and if they confer cross-tolerance and cross-resistance against antibiotics.
Methods:
We use time-kill assays in the presence of disinfectants and experimental evolution combined to whole-genome sequencing in the model organism E. coli.
Results:
We find persister sub-populations against chlorhexidine and quaternary ammonium compounds, but not to alcohols, aldehydes and oxidative compounds. We will present the relationship of mechanisms known to underlie antibiotic persister formation to the formation of persisters against disinfectants. In addition, we will present data from an ongoing evolution experiment for persistence against disinfectants.
Microorganisms perform multiple metabolic functions that shape the global cycling of elements, health and disease of their host organisms, and biotechnological processes. The rates, at which different metabolic activities are performed by individual cells, can vary between genetically identical cells within clonal populations. While the molecular mechanisms that result in such metabolic heterogeneity have attracted considerable interest, the environmental conditions that shape heterogeneity and its consequences have received attention only in recent years. Here, we review the environmental drivers that lead to metabolic heterogeneity with a focus on nutrient limitation, temporal fluctuations and spatial structure, and the functional consequences of such heterogeneity. We highlight studies using single-cell methods that allow direct investigation of metabolic heterogeneity and discuss the relevance of metabolic heterogeneity in complex microbial communities.
Sunlight, the major source of energy, drives life but in excess it provokes UV-induced DNA damage, accumulation of reactive oxygen species, desiccation, osmotic stresses and so on. Biological strategies to survive excess light include protection, avoidance and active utilisation. Phototrophic organisms including cyanobacteria, green algae and plants use all three strategies. Fungi occupying phototrophic niches may profit from the surplus photosynthetic products which also obliges them to cope with the same light-induced stresses. One way of handling these stresses would be to use similar signalling pathways to sense the presence and to interact with their phototrophic partners. Obviously, the levels of adaptation and responses to light will depend on the environment as well as fungal genotype and phylogenetic position. Black fungi – a polyphyletic group – accumulate the dark pigment DHN melanin in their cell walls and often occupy light-flooded habitats from phyllosphere to rock surfaces. Here we compare two sequenced melanised fungi of different lifestyles in their response to light.
The Leotiomycete Botrytis cinerea is an aggressive pathogen that primarily infects the above-ground parts of plants. It possesses large numbers of photoreceptors that respond to a broad spectrum of light. As a consequence, light controls morphogenesis in which it induces conidiation for disease spreading and represses sclerotial development for survival and/or sexual recombination. Cellular components involved in photo-perception and regulation of morphogenesis, stress responses and virulence have been identified and appear to regulate propagation, survival and infection. These include phytochromes, a group of photoreceptors which are particularly enriched in the Leotiomycetes and that mediate coordinated responses to light and elevated temperatures. Assuming that photo-regulation may be equally important for fungi that live in mutualistic relationships with phototrophs either by forming composite organisms or biofilms, we investigate the role of light in the rock-inhabiting Eurotiomycete Knufia petricola. Like other black yeasts, K. petricola grows slowly, does not form specialised reproductive structures and constitutively produces DHN melanin as well as carotenoids. Combining K. petricola with the cyanobacterium Nostoc punctiforme, we developed a model system for studying biofilm formation and bio-weathering. A genetic toolbox to manipulate this model system is being developed. K. petricola strain A95 possesses ten putative photoreceptors, more than found in filamentous Eurotiomycetes suggesting that light plays an important role for abiotic and biotic interactions in extremo-tolerant and symbiosis-capable fungi.
Fungi that share light-flooded habitats with phototrophs may profit from excess photosynthetic products. But to cope with sunlight-associated stresses it is important for fungi to accurately sense and respond to changes in light. To test the hypothesis that light is an environmental cue that Ascomycota use to coordinate growth, stress responses as well as to establish pathogenic or symbiotic relationships, the photoreceptor (PR) distribution in species from different ecological niches was analysed. The genomes of black fungi from phyllosphere and exposed solid surfaces contain multiple photoreceptors (PRs). The filamentous foliar plant pathogen Botrytis cinerea (Leotiomycetes) has a highly sophisticated photosensory and signalling system that helps to avoid light and to locate susceptible hosts. Rock-inhabiting Dothideo- and Eurotiomycetes including Knufia petricola possess equal numbers of PRs along with the same set of protective pigments. This similarity between black fungi from plant and rock surfaces suggests that photoperception and photoregulation are important for fungi that avoid loss of energy and nutrients through cooperation with phototrophs.
Black yeasts form a polyphyletic group of Ascomycota that colonize bare surfaces like rocks, facades of buildings, and solar panels. Their protective adaptations enable an adequate response to fluctuating and diverse temperature, water and UV radiation stresses. Together with bacteria and algae they form sub-aerial biofilms (SAB) this way discoloring and weathering the surfaces they grow on. Strain A95 of Knufia petricola (Eurotiomycetes, Chaetothyriales) displays both typical yeast-like cell growth and constitutive dihydroxynaphthalene (DHN) melanogenesis. Along with the cyanobacterium Nostoc punctiforme as photobiont, it is already used in a model system for studying SAB formation and bio-weathering. Applying the recently developed tools for the generation of deletion mutants will allow to define gene functions and to identify genes critical for abiotic and biotic interactions. We present a chromosome-level genome assembly and annotation for K. petricola A95. The genome was assembled with MaSuRCA using a hybrid assembly approach of Illumina MiSeq and PacBio SMRT sequencing data. The resulting assembly consists of 17 contigs including the complete mitochondrial genome and five complete chromosomes. It shows indication of repeat-induced point mutations (RIP). Supported by RNA sequencing data from eight different growth conditions, 10,994 genes were predicted with the BRAKER2 pipeline. Functional annotation of genes was obtained from general functional annotation databases and the fungal specific database FungiPath. Comparative analyses are in progress to identify genes specific to black yeasts, that may facilitate the survival on exposed surfaces. In sum, the genome sequence of K. petricola is a valuable resource to gain insight into the protein inventory and functional pathways of extremotolerant and symbiosis-capable fungi.
Fungi that share light-flooded habitats with phototrophs may profit from excess photosynthetic products. But to cope with sunlight-associated stresses it is important for fungi to accurately sense and respond to changes in light. To test the hypothesis that light is an environmental cue that Ascomycota use to coordinate growth, stress responses as well as to establish pathogenic or symbiotic relationships, the photoreceptor (PR) distribution in species from different ecological niches was analysed. The genomes of black fungi from phyllosphere and exposed solid surfaces contain multiple photoreceptors (PRs). The filamentous foliar plant pathogen Botrytis cinerea (Leotiomycetes) has a highly sophisticated photosensory and signalling system that helps to avoid light and to locate susceptible hosts. Rock-inhabiting Dothideo- and Eurotiomycetes including Knufia petricola possess equal numbers of PRs along with the same set of protective pigments. This similarity between black fungi from plant and rock surfaces suggests that photoperception and photoregulation are important for fungi that avoid loss of energy and nutrients through cooperation with phototrophs.
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.
The OECD test guidelines (TGs) for testing chemicals have been widely used for regulatory purposes all over the world since the establishment of the Mutual Acceptance of Data (MAD) principle in 1984. This MAD principle ensures that, if a chemical is tested under the Good Laboratory Practice (GLP) conditions accordingly to an OECD TG, the data should be accepted in all OECD countries. The TGs have been developed, harmonized, internationally validated (round robin tests) and adopted by OECD countries to be used for the physical-chemical characterisation, fate estimation, and hazard identification for risk assessment of various chemicals. In addition to the TGs, OECD Guidance Documents (GDs) usually provide guidance on how to use TGs and how to interpret the results. These GDs do not have to be fully experimentally validated, and hence they are not under MAD, but they are based on relevant published scientific research.
But are the existing TGs and the related GDs applicable and adequate for the regulatory testing of nanomaterials? In general, for nanomaterials it is accepted that most of the "endpoints" or more precisely measurement variables are applicable. However, for some endpoints new or amended TGs are needed. In addition, several GDs are needed to give more precise advice on the test performance in order to gain regulatory relevant data on nanomaterials.
Microbiologically induced corrosion due to bacterial biofilms causes several problems in industrial systems, technical applications and in medicine. Prior to the formation of a biofilm on a substrate, planktonic cells attach on the surface. Hence, the properties of the surface play a key role in biofilm formation and are of great importance for the development of strategies to prevent bacterial attachment and biofilm formation.
This project aims at clarifying to which extent surface micro-/nanostructuring and chemical functionalization affects bacterial attachment and whether a synergistic combination of the two can be used to control bacterial adhesion. To answer these questions, model surfaces with regular patterns of 5-10 micrometers in size have been prepared, which provide distinct zones differing in terms of their chemistry or nano-roughness. This was achieved by micro contact printing of self-assembled monolayers with different functional groups and deposition of patterned ZnO nanorod arrays for studying the effect of surface chemistry and morphology, respectively. Typical contrasts studied were combinations of positively/negatively charged, hydrophobic/hydrophilic or flat/rough.
The attachment behavior of bacteria on tailored surfaces were studied in a flow chamber as a function of time. The strain Pseudomonas fluorescens SBW25 was chosen as a model organism. DNA-intercalating dyes such as Syto9 have a high affinity to adsorb on ZnO nanorods. To overcome this limitation a genetic modification was performed by introducing a gene which expresses a green fluorescent protein in P. fluorescens SBW25 enabling the quantitative evaluation of the flow chamber studies by means of fluorescence microscopy. Further analysis of the attachment behavior was performed by means of scanning electron microscopy.
The presentation will summarize the results of our systematic study on the role of individual parameters on bacterial attachment and highlight synergistic combinations, showing an inhibition or enhancing effect. As the investigations with model substrates enable a precise control of the surface parameters, this approach can be applied to different microorganisms and material systems to achieve a correlative description of bacterial adhesion on solid surfaces.
The miraculously preserved 2000-year-old Dead Sea Scrolls, ancient texts of invaluable historical significance, were discovered in the mid-20th century in the caves of the Judean desert. The texts were mainly written on parchment and exhibit vast diversity in their states of preservation. One particular scroll, the 8-m-long Temple Scroll is especially notable because of its exceptional thinness and bright ivory color. The parchment has a layered structure, consisting of a collagenous base material and an atypical inorganic overlayer. We analyzed the chemistry of the inorganic layer using x-ray and Raman spectroscopies and discovered a variety of evaporitic sulfate salts. This points toward a unique ancient production technology in which the parchment was modified through the addition of the inorganic layer as a writing surface. Furthermore, understanding the properties of these minerals is particularly critical for the development of suitable conservation methods for the preservation of these invaluable historical documents.
Measurements of aerosol particles are vital for enforcing EU air quality regulations to protect human health, and for research on climate change effects. Although metrics such as PM10 and PM2.5 are currently in use, the level of uncertainty of aerosol metrics is too high and the traceability is insufficient. The project AEROMET, which has been started in June 2017 aims at implementing improvements in a) the uncertainty of particle mass, size and number concentration measurements and b) in the characterization of regulated components in airborne particles. Both are demanded by existing networks within the EU as well as by global atmospheric research.
On-site measurement campaigns
One of the objects is the application of mobile x-ray spectroscopy techniques combined with aerosol sampling techniques for quantifying particle compositions in the field for real time analysis. During two in-field measurement campaigns in Budapest, Hungary in May 2018 and Cassino, Italy in September 2018 the size dependent mass concentrations of specific elements in ambient aerosols were monitored under dynamic conditions.
Typically, airborne particles are sampled on filter substrates. During this project new sampling methods with specially designed substrate holders for an in-situ TXRF analysis were developed and applied for the first time. This approach allows a direct time and size resolved analysis without laborious digestion steps and a reduced risk of contamination.
Aerosol particles were sampled in a 13-stage DLPI impactor - size range from 0,03 µm to 10 µm - which was equipped with special adapters for acrylic discs of 30 mm diameter, serving as substrates. TXRF analysis was performed on site with the transportable spectrometer S2 PICOFOX (Bruker Nano GmbH) equipped with a Mo X-ray tube and a 30 mm² Silicon Drift Detector (SDD). Excitation conditions were 50 kV, 600 µA, measurement time 1000 s. Quantification was based on internal standardization using 50 ng of Y in solution, which was pipetted into the centre of the discs prior to sampling.
At moderate air pollution levels, i.e. PM10 ~ 20 µg/m³, sampling times of less than 2 hours were enough for the detection of elements in different particle size bins. The in-situ approach and the high sensitivity of TXRF enables the observation of rather quick changes in the quantity and distribution of elements in an ambient aerosol on the day of sampling, as the below example from the Cassino field campaign on 11 Sept. 2018 shows: The analysis of the morning and afternoon sampling shifts reveals the occurrence of the elements Fe, Ca and Si in different size bins as well as their significant temporal change in respective mass concentrations over the day while the distributions of several other elements in the aerosol remain unchanged.
The validation of these results by backup measurements is planned.
A mobile Bruker S2 Picofox TXRF spectrometer has been used in two field campaigns within the EMPIR env07 AEROMET project for the on-site analysis of cascade impactor aerosol samples.The results show that even at moderate air pollution levels – i.e.PM10 fairly below 20 μg/m³ - element mass concentrations in air in the range of 100 pg/m³could be measured in up to 13 size bins after sampling times of less than only 0.5 days.
Today glass is broadly used in modern architecture. For indoor applications it is possible to produce decorated glass by using enamel colours and glass painting techniques without any problems. However, this is more limited for applications out of doors. Humidity and environmental pollution attack the surface of the coating and can damage it. There are only a few colours on the market which are resistant towards acids and bases until now. Additionally, most of those colours are opaque. To extend the colour palette, chemically resistant low melting coloured glasses are being developed which are transparent and intensively toned even in thin coating thicknesses. To achieve such an ambitious aim, many parameters have to combine and act in a complex manner. New compositions of lead borosilicate, zinc borosilicate and lead-zinc borosilicate glasses were produced and milled as powder. The thermal properties as well as the environmental stability were analysed. The influence of PbO and ZnO on the thermal properties and the environmental stability were investigated. Evaluation of the fusing results shows that the production and mixture of transparent vitreous enamels for the exterior side of glasses is possible. The tests made it clear that the original materials for making the vitreous enamels must be excellently ground and prepared to achieve a satisfactory result. The method to produce durable vitreous enamels for exterior application also seems to allow the production of glass colours.
Since it was realized that sites contaminated with metals and radionuclides needed treatment, various remediation methods have been and are being developed. Depending on the size of the contaminated site and urgency of intervention, conventional or recently introduced techniques have been used. Conventional techniques include excavation and removal for treatment of soil and contaminants, or the so-called “pump-and-treat” method, in which contaminated groundwater is removed from the ground by pumping and treated in a treatment plant on the surface. It has the advantage of using proven techniques and is easy to control, and the treated groundwater can be reinjected into the ground or discharged in rivers or lakes. Novel methods include permeable reactive barriers, biomineralization, and electrokinetic remediation.
Waste, Evaluation Methods
(2019)
It is difficult to decide which waste management system fulfills best predefined sustainability goals such as maximum materials and energy recovery, least environmental impact, and lowest societal cost. Such decisions are based on many parameters. However, several evaluation methods exist with different scope and output, and the application of one or more evaluation methods provides an objective comparison of alternatives.
In the transition to the Circular Economy (CE) model, where the added value of products is kept as long as possible and waste is eliminated, the sustainable management of raw materials plays a key role. In above CE model, especial attention is paid to CRMs which are economically and strategically important for the European economy, but have a high-risk associated with their supply.
One of the most important element which can not be replaced and is an essential element for human nutrition, yet limited resource is phosphorus (P). An importance of issues related to sustainable P management results from EU legislation, which indicated P as a Critical Raw Material (CRM).
The sustainable management of P-resources is especially important for the Baltic region. A consequence of waterborne loads passing into the sea, mainly as wastewater with a high P content is the eutrophication of the Baltic Sea environment. Due to the largest inputs of P (37%) into the Baltic Sea originate from Poland, the development of sustainable solutions aimed at more rational P management for this country is externally important.
Due to the vital importance of phosphorus (P) and its increasing scarcity as a natural resource, phosphorus recovery has recently gained significant scientific and technical interest. An interesting sources of phosphorus are sewage sludge (SS) and sewage sludge ash (SSA) due to the major part of the phosphate from P rich wastewater is transferred to the sludge (approx. 90%). Despite the fact that the raw materials base is large (PURE report indicates that in 2020 the amount of sewage sludge generated in Poland will reach 180% of the dry matter of sewage sludge produced in 2010), at present recycling of phosphorus is not a commonly used practice in Poland.
Phosphorus (P) recycling from sewage sludge for agricultural needs has to meet requirements for agricultural implementation, such as short and long-term P-plant-availability under field conditions. Field experiments often bring no evaluable results, because agricultural soils got a high potential of P-supply even if they are classified as low in P-supply according to the CAL extraction method. The present study presents a possible way to investigate the P-plant-availability of P-recycling-fertilizers under field-like conditions. The plant experiments are firstly performed in small Mitscherlich pots in growth chambers and subsequently in containers with a high soil volume of 170 kg under greenhouse conditions, in which plants can grow until ripening. The tested P-recycling fertilizers were produced from sewage sludge in a large-scale thermal process. It was a two-step treatment process performed with a pyrolysis of sewage sludge at 550°C (SSC-550) and a subsequent thermochemical post-treatment at 950°C with Na2SO4 (SSA-Na) and HCl + Na2SO4 (SSA-HCl/Na) as additives. The results show, that the P-recycling-products from pyrolysis got an adequate long-term but a 65% lower short-term P-plant-availability compared to triple superphosphate. SSA-Na and SSA-HCl/Na show both a high short and longterm P-plant-availability comparable to triple-superphosphate. This can be explained by their highly plant-available P-compound CaNaPO4.
This work addresses the identification of synthetic organic pigments (SOP) in ten modern reverse paintings on glass (1912-1946) by means of an in-situ multi-analytical approach. The combination of the complimentary properties of mobile Raman spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) enabled the detection of sixteen SOP even in complex mixtures with inorganic compounds and binders. For the β-naphthol pigments, both Raman and DRIFTS yield appropriate results. DRIFTS was the preferred method for the detection of synthetic alizarin (PR83). Its diagnostic band pattern even allows its detection in complex mixtures with mineral pigments, binders and fillers. Raman spectroscopy yielded distinctive spectra for the triaryl carbonium pigments (PG1, PV2, PR81) and the two-yellow azo SOP (PY3, PY12), whereas DRIFT spectra were affected by extensive band overlapping. This may also occur in Raman spectra, but in less problematic amounts. Fluorescence is the major problem with Raman and it significantly hampers the SOP spectra even with the 785 nm laser. On the one hand the big spot size of DRIFTS (10 mm) limits the technique to rather large sampling areas, whereas the use of a 50× objective for in-situ Raman measurements permits a focus on small spots and aggregated SOP flakes. Moreover, “environmental” factors like temperature changes, artificial light, limited space and vibrations when people pass by need to be considered for in-situ measurements in museums.
Finally, the results show the experimental use of SOP in modern reverse glass paintings. Among several rare SOP (e.g. PB52, PR81), two of them (PG1, PV2) have never been reported before in any artwork.
First insights into Chinese reverse glass paintings gained by non invasive spectroscopic analysis
(2019)
A non-invasive methodological approach (X-ray fluorescence (XRF), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), Raman spectroscopy) has been carried out to identify the pigments and classify the binding media in two Chinese reverse glass paintings (The Archer, Yingying and Hongniang) from the late 19th and early 20th centuries. The results reveal a combined use of traditional Chinese and imported European materials. Several pigments like cinnabar, lead white, orpiment, carbon black and copper-arsenic green (probably emerald green) were found in both paintings; red lead, artificial ultramarine blue, Prussian blue and ochre appear in at least one of the paintings.
The presence of portlandite (Ca(OH)2) along calcite (CaCO3) in the fine-grained, white backing layer of Yingying and Hongniang indicates the presence of limewash. In Chinese tradition, limewash was produced from clamshells, and was then sold as clamshell white. In contrast to the Japanese pigment, Chinese clamshell white was made of finely grounded shells, which were heated over a low fire. The residue (CaO) forms portlandite (Ca(OH)2) when water is continuously added. This water-rich mixture is applied on the painting. Portlandite reacts with atmospheric CO2 during drying and forms fine-grained calcite (CaCO3) [1,2].
The identification of emerald green (The Archer) suggests an earliest manufacturing date in the 1830s [3] and promotes the sinological dating of the painting. Drying oil was classified as a binding media in most areas of both paintings. However, the orange background of The Archer yielded prominent bands of both proteinaceous and fatty binder.
A non-invasive methodological approach has been carried out to identify the pigments and classify the binding media of the reverse painting on glass Kreuzabnahme (1914/15) by Carlo Mense.
Mense was a member of the group Rhenish Expressionists around August Macke and got interested in the technique of painting on the reverse side of a glass panel. The studied painting indicates a remarkably painted reverse and front side, which creates a unique visual appearance of the glass. The applied noninvasive, spectroscopic approach includes X-ray fluorescence, VIS spectroscopy, Raman spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy. The measurements revealed inorganic Pigments mixed with drying oil as binder. Together with common pigments, such as lead white, barium sulphate, bone black, cinnabar, chrome yellow, ochre, and viridian, an unusual additional material was found, Strontium white.
This work highlights the rediscovery of the technique of reverse glass painting by the artists of the “Blaue Reiter” collective in the early 20th-century and focusses particularly on the role of Wassily Kandinsky (1866–1944). Kandinsky created more than 70 reverse paintings on glass and showed several of them in exhibitions together with paintings on canvas and cardboard, implying a coequal importance of these techniques. Four of his early (1911–1914) reverse glass paintings (Auferstehung, Allerheiligen II, Rudern, Apokalyptischer Reiter II) were selected for investigation and their iconography, painting techniques and painting materials were examined. Two paintings were executed on so-called cathedral glass, revealing a “hammered surface”, whereas Kandinsky used a corrugated glass panel for Rudern. A multi-analytical, non-invasive approach [X-ray fluorescence (XRF), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), VIS spectroscopy (VIS), Raman spectroscopy] was taken to identify the pigments and classify the binding media. The results reveal a broad palette of materials. Several pigments like lead white, zinc white, Strontium yellow, Prussian blue, viridian, cadmium yellow, ultramarine blue, cinnabar and carbon black were found in most of the four paintings. The use of the rare synthetic organic pigments PR60 and PB52 is discussed. In two works of art, cadmium carbonate is associated with cadmium yellow. The identification of aluminium foil along with tin foils in Rudern indicates an early use of this material for reverse glass paintings.
This work presents a technical investigation of two Chinese reverse glass paintings from the late 19th and early 20th centuries. A multi-analytical, non-invasive approach (X-ray fluorescence (XRF), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), Raman spectroscopy) was used to identify the pigments and classify the binding media. The results reveal a combined use of traditional Chinese and imported European materials. Several pigments like cinnabar, lead white, orpiment, carbon black and copper-arsenic green (probably emerald green) were found in both paintings; red lead, artificial ultramarine blue, Prussian blue and ochre appear in at least one of the paintings. The proof of limewash (calcite and small amounts of portlandite) as a backing layer in Yingying and Hongniang indicates that clamshell white was also used for reverse glass paintings. Drying oil was classified as a binding media in most areas of both paintings. However, the orange background of The Archer yielded prominent bands of both proteinaceous and fatty binder.
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.
An understanding of the interactions of 2D nanomaterials with pathogens is of vital importance to developing and controlling their antimicrobial properties. In this work, the interaction of functionalized graphene with tunable hydrophobicity and bacteria is investigated. Poly-(ethylene glycol)-block-(poly-N-isopropylacrylamide) copolymer (PEG-b-PNIPAM) with the triazine joint point was attached to the graphene Surface by a nitrene [2 + 1] cycloaddition reaction. By thermally switching between hydrophobic and hydrophilic states, functionalized graphene sheets were able to bind to bacteria. Bacteria were eventually disrupted when the functionality was switched to the hydrophobic state. On the basis of measuring the different microscopy methods and a live/dead viability assay, it was found that Escherichia coli (E. coli) bacteria are more susceptible to hydrophobic interactions than B. cereus bacteria, under the same conditions. Our investigations confirm that hydrophobic interaction is one of the main driving forces at the presented graphene/bacteria interfaces and promotes the antibacterial activity of graphene derivatives significantly.
An existing pyrometallurgical process for tantalum and niobium recovery, mainly from low grade pyrometallurgical residues, was investigated. Series of melting experiments were carried out in a pilot-scale electric arc furnace to study how the amount, the grain size and the way of feeding affect the activity of carbon as a reducing agent. During the pyrometallurgical treatment refractory metals such as tantalum and niobium are reduced to their carbide form and enriched in the molten iron-based metal phase. The cooled down slag and metal phase were analysed to investigate thermodynamic and kinetic conditions of the carbide formation. FACT Sage simulations were also used to investigate the material system in state of thermodynamic equilibrium. Results show that mass transfer and kinetics may play an important role if compared to equilibrium analyses using FACT Sage.
An existing pyrometallurgical process for tantalum and niobium recovery, mainly from low grade pyrometallurgical residues, was investigated. Series of melting experiments were carried out in a pilot-scale electric arc furnace to study how the amount, the grain size and the way of feeding affect the activity of carbon as a reducing agent. During the pyrometallurgical treatment refractory metals such as tantalum and niobium are reduced to their carbide form and enriched in the molten iron-based metal phase. The cooled down slag and metal phase were analysed to investigate thermodynamic and kinetic conditions of the carbide formation. FACT Sage simulations were also used to investigate the material system in state of thermodynamic equilibrium. Results show that mass transfer and kinetics may play an important role if compared to equilibrium analyses using FACT Sage.
19th and 20th centuries glass paint layers consist of a colour body and a colourless lead silicate flux, in which borax or boric acid was added as further component to improve the paint ability and to reduce the firing temperature for multiple layers of paint. Model glasses were used in laboratory tests to investigate the stability of glass paints with additions of boron oxide. To determine boron in paint layers, a LIBS-system with pulsed NdYAG-laser was used.
Medieval stained-glass windows are protected by an outside gazing system in many churches.The interspace between the original and the protective glass is ventilated with air from the indoor or exterior environment, where dust and particles can move.Cascade impactor measurements and SEM/EDX analyses of sampled dust were carried to determine the dust composition. The effect of particles on model glass samples was investigated in climate chambers under accelerated weathering conditions. The results from in situ measurements and laboratory tests were combined to evaluate the potential effect of particulate matter on historic stained-glass Windows.
The church of Koszewko (Poland) is a brick building edified in the 15th century built on cobblestone foundations. There are five windows in the sanctuary. Three of them enclose heraldic panels from the Küssow’s family from the 15th century which are surrounded with Goethe glass from the 18th century to complete the windows. The colored heraldic panels are strongly damaged and corroded with massive paint layer losses, glass- and leadbreakages. Those medieval glass fragments have been shortly discovered and are of particular interest for Poland since only few medieval glazing have been conserved.
The damages as well as the glass compositions have been investigated with ESEM/EDX. Two categories of medieval glass compositions have been identified. The blue glass is particularly sensible to corrosion because of his high content in K2O. The colorless and the red glass samples belong to a stable glass type. Due to the thickness of the gel layer, it is easy to see that the degradation is strongly proceeded. The protection of those medieval stained-glass panels is absolute necessary.
The medieval panels have been restored and surrounded from a copper frame. Then they have been fixed on the wood frame in the church. The exterior glazing has been closed with a panel of Goethe glass. The gap between the Goethe- and the medieval glass is about 3 cm. The Goethe glass panel has been stabilized with a film based on polyester to protect the medieval glasses against any damages. In this way, a low cost protective glazing has been installed for a long-term conservation of each medieval stained-glass panels. The climate measurements over the period of one year on the restored windows are in process. The temperature and the relative humidity are recorded in the church interior, in the gap between the original and the Goethe glass and outdoors.
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.