4 Material und Umwelt
Filtern
Dokumenttyp
- Vortrag (273) (entfernen)
Sprache
- Englisch (273) (entfernen)
Referierte Publikation
- nein (273)
Schlagworte
- Biocides (20)
- Antimicrobial resistance (19)
- Ink (14)
- Biofilms (12)
- MIC (10)
- Antimicrobial coating (9)
- Bacteria (9)
- Corrosion (9)
- Recycling (9)
- Evolution (8)
Organisationseinheit der BAM
- 4 Material und Umwelt (273)
- 4.1 Biologische Materialschädigung und Referenzorganismen (73)
- 4.5 Kunst- und Kulturgutanalyse (48)
- 4.2 Material-Mikrobiom Wechselwirkungen (44)
- 4.0 Abteilungsleitung und andere (41)
- 4.4 Thermochemische Reststoffbehandlung und Wertstoffrückgewinnung (39)
- 4.3 Schadstofftransfer und Umwelttechnologien (37)
- 6 Materialchemie (23)
- 1 Analytische Chemie; Referenzmaterialien (17)
- 6.1 Oberflächen- und Dünnschichtanalyse (13)
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 processing of laser-induced periodic surface structures (LIPSS) represents a simple and robust way for the nanostructuring of solids that allows creating a wide range of surface functionalities featuring applications in optics, tribology, medicine, energy technologies, etc. While the currently available laser and scanner technology already allows surface processing rates at the m2/min level, industrial applications of LIPSS are sometimes hampered by the complex interplay between the nanoscale surface topography and the specific surface chemistry. This typically manifests in difficulties to control the processing of LIPSS and in limitations to ensure the long-term stability of the created surface functions. This presentation aims to identify some unsolved scientific problems related to LIPSS, discusses the pending technological limitations, and sketches the current state of theoretical modelling. Hereby, it is intended to stimulate further research and developments in the field of LIPSS for overcoming these limitations and for supporting the transfer of the LIPSS technology into industry.
Here, we describe a fast and simple extraction method for the determination of per- and polyfluorinated alkyl substances (PFASs) utilizing extractable organic fluorine (EOF) sum parameter analysis and high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) in soil samples. After extraction and separation of inorganic and organic fluorinated compounds, organically bound fluorinated compounds were indirectly determined via the molecular absorption of gallium mono-fluoride at 211.248 nm. The implementation of the decisions of the “Stockholm Convention on persistent organic pollutants” as well as the “Protocol on Persistent Organic Pollutants of the Convention on Long-Range Transboundary Air Pollution” of the UNECE include the reduction respectively the elimination of PFASs in the environment. Currently, regulations aim to target single compounds (mostly C8-PFAS). But the PFAS group includes over 4700 substances, which are potentially persistent and toxic, thus target analytical approaches are not suitable for a holistic approach investigating the PFAS pollutant situation. Furthermore, forbidden PFASs are substituted by short-chain PFASs, thus the number of unknow substances is steadily increasing. For this reason, sum parameter approaches are more suitable to investigate and assess the pollution situation as well as derive exposure limits. Our developed analytical method was successfully applied to determine PFASs in soil samples from a polluted site. In view of steadily increasing numbers of PFAS substances, our method will make an important contribution in assessing the pollution situation as well as support policy makers in deriving exposure limits for PFAS in the future.
Adipokinetic hormone (AKH) is a neuropeptide produced in the insect corpora cardiaca that plays an essential role in mobilizing carbohydrates and lipids from the fat body to the hemolymph. AKH acts by binding to a rhodopsin-like G protein-coupled receptor (GPCR), the adipokinetic hormone receptor (AKHR). In this study, we tackle AKH ligand and receptor gene evolution as well as the evolutionary origins of AKH gene paralogues from the order Blattodea (termites and cockroaches). Phylogenetic analyses of AKH precursor sequences point to an ancient AKH gene duplication event in the common ancestor of Blaberoidea, yielding a new group of putative decapeptides. In total, 16 different AKH peptides from 90 species were obtained. Two octapeptides and seven putatively novel decapeptides are predicted for the first time. AKH receptor (AKHRs) sequences from 18 species, spanning solitary cockroaches and subsocial woodroaches as well as lower and higher termites, were subsequently acquired using classical molecular methods and in silico approaches employing transcriptomic data. Aligned AKHR open reading frames revealed 7 highly conserved transmembrane regions, a typical arrangement for GPCRs. Phylogenetic analyses based on AKHR sequences support accepted relationships among termite and cockroach lineages to a large extent, while putative post-translational modification sites do not greatly differ between solitary and subsocial roaches and social termites. This study provides important information not only for AKH and AKHR functional research but also for further analyses interested in their development as potential candidates for biorational pest control agents against invasive termites and cockroaches.
During the last decades the material composition of buildings has become increasingly diverse. However, largely sorted material flows are needed for generating high quality secondary building materials. The use of secondary building materials can meet the requirements of sustainability in several ways: the extended time availability of primary raw materials and, thereby, the preservation of natural resources as well as the conservation of landfill sites.
Recycling of gypsum (calcium sulfate) can be a good example for the environmental benefits of closed-loop recycling. The content of sulfates in other secondary building materials, in particular in recycled concrete aggregates, should be minimized for quality reasons. In contrast, separated gypsum can also be used in gypsum production if the high quality requirements for the recycled gypsum are met. Since almost all processing steps in the recycling process are associated with environmental impacts, an environmental evaluation of the use of recycled gypsum as a substitute in gypsum production has to be carefully conducted.
This paper focusses on the techniques for generating recycled gypsum from gypsum plasterboards, the related quality requirements and a comprehensive environmental evaluation of the complete process.
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.
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.
Die Präsentation erläutert die Hintergründe der nationalen Anforderungen für die Verwendung von Kunststoffdichtungbahnen in Deponieabdichtungen. Die Beständigkeit wird diskutiert. Anforderungen an das Qualitatsmanagement während der Produktion der Produkte und der Bauphase werden aufgezeigt und die Auswirkungen auf die langzeitige Funktionserfüllung werden beschrieben.
The aim of this study was to investigate the passive sampler method Diffusive Gradients in Thin-films (DGT) for ammonium and nitrate in amended soils. Therefore, we used soils from a pot experiment with maize where nitrogen (N) was supplied as ammonium sulfate nitrate (ASN), without and with a nitrification inhibitor (NI). The additional use of a NI can delay the nitrification in the soil and making the ammonium available for a longer period in the soil solution after its application. Homogenized soil samples were collected directly from each pot after one week of incubation before sowing and after harvesting the maize. Nitrate and ammonium in these soil samples were extracted using DGT devices equipped with a Putolite A520E (for nitrate) and Microlite PrCH (for ammonium) binding layer. Ammonium DGT which determined the mobile and labile ammonium forms based on diffusion and the resupplies from the solid soil phase, only showed a significantly higher amount of extractable ammonium with NI compared to that without NI for some samples. However, significantly lower values were found for nitrate of treatments with NI compared to without NI after harvest. Thus, the lower nitrate amounts for treatments with NI compared to the treatments without NI after harvest indicated the delay of the nitrification process by the NI. Furthermore, we compared also the ammonium and nitrate
DGT results to chemical extraction with KCl solutions. The results demonstrated that the trends of DGT results and chemical extraction were complimentary through all the treatments.
This talk will be divided into two parts. In the first part I will present the analytical techniques and the equipment used by the Centre for the Study of Manuscript Cultures that can be applied for the study of decorated papers. The analyses aim to determine the constituent materials of papers, pigments, dyes and metals and the techniques used for their production. I will focus in particular on the kind of information these techniques allow us to gather: through optical microscopy we conduct fibre analysis in order to identify the plant used as raw material in paper production while Reflectography, X-Ray Fluorescence and InfraRed, Raman and Visible Reflectance Spectroscopy are used to study the sizing agents, the pigments, dyes and metals. In the second part I will show some results obtained by the application of these techniques on a few Persianate manuscripts, dating between the 15th and 17th centuries, belonging to the corpus of Ilse Sturkenboom.
In the 15th century, Persian manuscripts underwent significant and lasting changes. Possibly as a response to the import of tinted and gold-decorated paper from China, which was used for manuscript production in Greater Iran, Persian papers were also tinted and embellished with gold-decorated and marbled margins or frames. In a joint project between CSMC and the University of St Andrews, and in co-operation with the Golestan Palace Museum, we aim to analyse papers and their decorations in manuscripts in the holdings of the Golestan Palace Library. The analyses aim to determine the consistencies of papers, pigments and metals and the techniques used for their production and application. The support will be first described in its codicological characteristics such as dimensions, thickness, colour (expressed in colour coordinates), pattern left from the sieve (observed in transmitted light). The plant used as raw material in paper production will be studied by fibres analysis, while the sizing agents, the pigments, dyes and metals will be analysed by the application of several methods: in particular Reflectography, X-Ray Fluorescence and InfraRed, Raman and Visible Reflectance Spectroscopy. The results of the analyses will be published in an online database that will form an important resource for the material aspects of Persian manuscripts and be a starting point for establishing a first chronology of the materials and techniques used in Persian manuscript production.
Quantitative chemical analysis of airborne particulate matter (PM) is vital for the understanding of health effects in indoor and outdoor environments, as well as for enforcing air quality regulations. Typically, airborne particles are sampled over long time periods on filters, followed by lab-based analysis, e.g., with inductively coupled plasma mass spectrometry (ICP-MS). Within the EURAMET EMPIR AEROMET project, cascade impactor aerosol sampling was combined for the first time with on-site total reflection X-ray fluorescence (TXRF) spectroscopy to develop a tool for quantifying particle element compositions within short time intervals and even on-site. This makes variations of aerosol chemistry observable with time resolution of only a few hours and with good size resolution in the PM10 range. A proof of principles of this methodological approach and the comparison to standard methods within the scope of a field campaign will be presented. Secondly, aerosol sampling and TXRF analysis seems suitable for the quantification of elements in indoor aerosols as well and may provide an important enhancement of existing methods for the analysis of organic species in aerosols (such as sampling and TD-GC/MS). As an example, the TXRF analysis of particles emitted from laser printers under controlled conditions in an environmental test chamber will be presented.
Per- and polyfluoroalkyl substances (PFAS) have emerged over the course of the last twenty years as a global pollution issue. Altogether, there are currently more than 4700 known but only partly characterized fluorinated compounds identified by the Organization for Economic Cooperation and Development (OECD), as shown by a recently published classification proposal.
The ongoing production of new, yet unrestricted PFAS alternatives has become a major challenge for environmental routine analytics, since the state-of-the-art method LC-MS/MS relies on structural information and availability of isotope standards of the targeted compound. First reported by Miyake et al., fluorine sum parameters like adsorbable organic fluorine (AOF), extractable organic fluorine (EOF) and total fluorine (TF) can be applied to survey and detect the presence of large amounts of unidentified organofluorine compounds in environmental matrices. Today fluorine sum parameters have been established as a useful supplement to classic target-analytical approaches of PFAS and were implemented for the first time as a sum value “PFAS-total” in the recently revised Drinking Water Directive (2020/2184) by the European Commission.
In contrast, X-ray absorption near-edge structure (XANES) spectroscopy has been widely applied to identify low concentration of element-specific contamination without pre-treatment in environmental samples in the past. The XANES approach enables a penetration depth of approx. 1 µm (at fluorine K-edge energy; depending on the matrix) which is significantly deeper than for X-ray photoelectron spectroscopy (XPS; penetration depth approx. 10 nm). Furthermore, the method is fast, non-destructive and only simple preparation of the samples is required.
In our work, we combined both F-XANES spectroscopy and combustion ion chromatography (CIC) in order to present a new analytical perspective on the investigation of PFAS in environmental media and material samples.
The mayor part of the Berlin collection `Manuscripta Americana´ consists of documents compiled by Alexander von Humboldt. The diversity of the written fragments and their shape presume few accordance concerning purpose, place or time of production. Even before the papers came to Berlin, manuscripts were copied, divided and collected by famous scholars also in Mexico. Back in Europe, Humboldt visited further collections and published the detected hieroglyphic writings altogether with cultural objects and landscapes in the book `Vues des Cordillères et Monuments des Peuples Indigènes de l`Amerique, voyage de Humboldt et Bonpland´, labelled corresponding to the cultural background.
By scientific and culture historical analyses, the Humboldt codices are revised and related to each other and others. In especial, the compilation of fragments shown on plate 36 in the book is looked at more closely. Whereas most of the plates represent only one sheet of painted amate paper, here segments with details of seven fragments are put together. It is tried to comprehend why these pieces are on one plate.
To find out a common feature of the documents, their content and represented form are compared. A correlation between some pieces is obvious and thus is also expected in the manufacture of the codices, in the kind of material used. For this the inks and colors are determined by scientific analysis including XRF-, Raman-, FTIR- and VIS- spectroscopy. Special material is detected and related to results of former analysis of codices written during the colonial period of America. Herewith a clear cultural assignment of the manuscripts is performed.
A relation of the fragments represented on plate 36 among each other and to other codices of the collection Manuscripta Americana in Berlin is discussed. Also, if the manuscripts are unique `originals´ or represent fragments of documents, whose corresponding pieces maybe found- in the best case- incorporated in other collections. We detected, that at least two of them can be put into relation to similar manuscripts deposited in Mexico. Further material analysis should clarify, if the corresponding pieces are identical- from one document, or if one of them is a copy. Herewith an approximation to authenticity features and history is issued.
Analytical Challenges for PFAS in Environmental Samples - Methods, Approaches and Applicability
(2022)
Per- and polyfluoroalkyl substances (PFAS) are anionic, cationic and zwitterionic synthetic products, in which the hydrogen atoms on the carbon skeleton of at least one carbon atom have been completely replaced by fluorine atoms and which include up to 1.7 M compounds, depending on the definition. As a result of continuous and prolific use, mainly in aviation firefighting foams, thousands of industrial and military installations have been found to contain contaminated soil, groundwater and surface water. Furthermore, because of the continuous contamination through PFAS containing commercial products, effluents and sewage sludge from WWTPs have been shown to be an important source of PFAS discharge into the aquatic environment. In the last few years, legacy PFAS (≥C4) have been found in various environments, including soil, water and wastewater, and their environmental pathways have been partly described.
Several long-chain PFAS species, and their respective salts are considered as persistent organic pollutants by the United Nations Stockholm Convention. These pollutants have been linked to altered immune and thyroid function, liver disease, lipid and insulin dysregulation, kidney disease, adverse reproductive and developmental outcomes, and cancer. A significant shift in the chemical industry towards production of short (C4-C7) and ultrashort (C1-C3) alternatives was observed in response to recently intensified regulations and restrictions on the use of long-chain (≥C8) PFAS. PFAS analysis in environmental samples is currently mainly done by liquid chromatography tandem mass spectrometry (LC-MS/MS). This efficient method is conducted in a targeted fashion analyzing a small subset of PFAS. The US EPA method for analysis of PFAS using LC-MS/MS for example currently lists 40 PFAS (≥C4). However, to get a better overview of the amount of “total PFAS,” sum parameter methods like total oxidizable precursor (TOP) assay and methods based on combustion ion chromatography (CIC) are in development. CIC results in data regarding the sum of absorbable organic fluorine (AOF) or extractable organic fluorine (EOF), which can also quantify other organically bound fluorine compounds such as fluorinated pesticides and pharmaceutical. Moreover, non-target and suspect screening mass spectrometry can be used to identify novel emerging PFAS and partly unknown fluorinated compounds in environmental samples. Furthermore, to analyze ultrashort PFAS (C1-C3), supercritical fluid chromatography (SFC), hydrophilic interaction chromatography (HILIC) and gas chromatography-mass spectrometry (GC-MS) are available, but further research is needed to develop reliable and accurate methods to quantify several ultrashort PFAS in environmental samples.
Additionally, for research purpose several spectroscopical methods like X-ray photoelectron spectroscopy (XPS), fluorine K-edge X-ray absorption near-edge structure (XANES)spectroscopy, particular induced gamma-ray emission (PIGE) spectroscopy and 19F nuclear magnetic resonance (NMR) spectroscopy are available.
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 overarching goal of this project is to develop a predictive model for efflux-mediated antimicrobial tolerance in bacterial multicellular assemblies. Our central hypostasis is that efflux pump activity causes emergent antibiotic tolerance of multicellular bacterial populations, through the interplay of efflux mediated spatial interactions and efflux-linked persistence. To test this hypothesis, we will use a combination of microscopy, microbial killing assays, computational modelling, and data analysis, integrating information from 3 types of multicellular assembly: colonies, cell-to-cell interactions in a monolayer microfluidic device, and 3D flow chamber biofilms. Building on our preliminary observations, we will experimentally characterize the link between colony structure and spatial patterns of efflux gene expression in strains that differ in their levels of efflux. We will develop a mathematical model to test whether local growth inhibition of neighbors due to effluxing cells, coupled with local environment-dependent regulation of efflux, can account qualitatively for these results. By including persister cell formation in our model we will predict, and measure, the emergent function of antimicrobial tolerance in our colonies. To fully understand how tolerance emerges from the interplay between efflux-mediated spatial interactions and efflux-linked persister cell formation, we need quantitative measurements at the single cell level. To this end, we will use a microfluidic setup with cells growing in a monolayer to qualify in detail the dependence of efflux expression and persister cell formation on nutrient conditions, the correlation between efflux and persister formation, and the spatial range of efflux-mediated neighbour growth inhibition. To predict and quantitatively understand the emergent multicellular function of tolerance, we will perform individual-based modelling of biofilm growth, using as input the parameters measured on the single-cell level with our microfluidics experiments. Our simulations will predict biofilm spatial structure development, patterns of efflux and persister formation and, ultimately, tolerance to antimicrobial challenge. These predictions will be directly tested in flow-cell biofilm experiments. We are currently generating acrAB-tolC knockout-strain, without efflux activity, and a strain with an inducible acrAB-tolC efflux pump. To distinguish the different strains under the microscope, they were labeled with genes encoding for different fluorescent proteins. All strains are currently characterized in terms of growth, minimum inhibitory concentration of different antimicrobial substances, colony morphology, and biofilm formation ability. On the theoretical side, we are currently working on modeling the system at various scales and degree of detail, ranging from coarse-grained continuum models to stochastic, individual-based models. Some exploratory work was doe to test existing software for individual-based modelling that may be adapted for our purpose. Furthermore, we are in the process of developing more coarse-grained models. This work involves some physiological modelling and literature search, focusing on working mechanisms of efflux pumps and kinetic models for import and export of antibiotics.
Biocides are in contact with soils through direct application and passive leaching from protected materials. Consequently, soil microorganisms are exposed to 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).
In adaptive laboratory evolution experiments we cultured selected model soil microorganism with representative biocides under selection regimes with increasing and stable biocide concentrations followed by antibiotic and biocide cross-resistance determination. Moreover, we investigate if the selected biocides affect the rates of de novo mutations and HGT of plasmids that carry resistance genes among soil microorganism.
Our results show only small increases of biocide resistance during serial transfers under increasing biocide concentrations. One reason for this might be the narrow selective window for biocide resistance due to steep dose-response relationships. Furthermore, our results indicate that a stable low-level biocide regime did not select for high level cross-resistance to antibiotics and other biocides.
Moreover, material preservatives affected the rates of HGT via conjugation and the mutation rates at sub-inhibitory concentrations. The results will enable future risk assessment regarding resistance evolution for biocides used as material preservatives.
A wide range of analytical methods are used to estimate the plant-availability of soil phosphorus (P). Previous investigations showed that analytical methods based on the Diffusive Gradients in Thin films (DGT) technique provide a very good correlations to the amount of bioavailable nutrients and pollutants in environmental samples (Davison 2016, Vogel et al. 2017). However, the DGT results do not identify which P compound of the soil has the high bioavailability. But there are various spectroscopic techniques (infrared, Raman, P K-edge and L-edge XANES and P NMR spectroscopy) available to characterize P species in soils. Therefore, spectroscopic investigation of DGT binding layers after deployment allow us to determine the specific compounds. Nutrients such as phosphorus and nitrogen are often, together with other elements, present as molecules in the environment. These ions are detectable and distinguishable by infrared, P K- and L-edge X-ray absorption near-edge structure (XANES) and NMR spectroscopy, respectively. Additionally, microspectroscopic techniques make it also possible to analyze P compounds on the DGT binding layer with a lateral resolution down to 1 μm2. Therefore, species of elements and compounds of e.g. a spatial soil segment (e.g. rhizosphere) can be mapped and analyzed, providing valuable insight to understand the dynamics of nutrients in the environment.
The challenge of the project ASHES is focused on the recycling of nutrients from residues of thermochemical processing of by-products of sugar cane industry (bagasse/straw) in Brazil to increase the energy efficiency of thermal conversion and to enable the recycling of process ashes as fertilisers. Dry lignocellulosic biomass (straw, bagasse) are combusted, gasified and subsequently combined with post-thermochemical treatment in the AshDec process to increase the plant availability of phosphorus. Different fertilizer formulations are granulated/pelletized and tested regarding their storage/handling characteristics.
Recent studies have shown that host-microbiota interactions can lead to dramatic changes in host phenotype especially behaviour. We investigate the causal drivers of microbe-associated shifts in host phenotype by examining how feeding behaviour is modulated by a bacterial infection in an omnivorous cockroach: Blatta orientalis. We conducted food-choice experiments after challenging hosts with the common entomopathogenic soil bacterium Pseudomonas entomophila to understand the impact of bacterial pathogens on host macronutrient preference. We find that immune challenge by this bacterium drives a sharp decline in carbohydrate intake and results in a relative increase in the ratio of protein to carbohydrate consumed. Additionally, infected cockroaches reduce their overall nutrient intake. We show for the first time that cockroach feeding behaviour is dynamically modulated by a pathogen. In contrast to studies on Spodoptera moths, this modulation does not impact any of the immune parameters we measured: it does not affect the abundance of immune related proteins in the hemolymph, hemolymph antimicrobial activity, or survival. This leads to the possibility that as long-lived omnivorous species B. orientalis may be better adapted to unpredictable variation in food availability and quality. An illness-induced anorexia-like response which is thought to assist hosts in limiting nutritional resources available to pathogens is therefore the most likely cause of the observed phenotype. Reduction of carbohydrate intake by sick individuals would be consistent with such an explanation.
In another cockroach species Blatella germanica we also investigate whether in addition to pathogens, host microbiota especially gut commensals are causally responsible for shifts in host behavioural phenotype and immune competence. To address this, we conduct food-choice and immunechallenge experiments in germ-free cockroaches and naïve cockroaches.
Results:
- Four types of inks were measured iron gall (vitriolic and non vitriolic), carbonic, mixed and vegetable inks.
- We need to start analyzing systematically the organic part of the inks.
- Great variety in the composition of the inks.
- No correlation between the type of ink used and any other criteria apart from a personal preference.
- Inks purchased by (some) scribes.
- Reconstruction of the chronology of writing and signing of certain legal documents.
- Comparison with documents written by the Muslim court.
BIOCIDE
(2022)
SRB are environmentally and industrially important microorganisms. The disadvantage of their metabolic activity (e.g. sulfate reduction) results in the formation of toxic sulfide that leads to microbial influenced corrosion. SRB have been responsible for biocorrosion of ferrous metal. One of mitigation strategy is the use of biocides. However, it has been shown that various bacteria develop antimicrobial resistance due to excessive use of biocides. Thus, a deeper understanding of the evolution of biocide resistance of SRB is necessary. Three commonly used biocides, THPS, BAC, and GLUT were applied to investigate the susceptibility of Desulfovibrio alaskensis G20.The minimum inhibitory and bactericidal concentration and the killing kinetics of the three biocides was determined. These results will be used to conduct evolution experiments to determine the evolution of resistance towards biocides of SRBs. The outcome of this work can be helpful to improve the management of MIC treatments.
Antimicrobial resistance (AMR) is a global health problem with the environment being an important compartment for the evolution, selection and transmission of AMR. These processes are impacted by pollution with antibiotics. However, biocides used as disinfectants and material preservatives are major pollutants by far excceding the market for antibiotics in terms of mass. Our work shows that biocides have the potential to affect evolutionary processes towards AMR by increasing the rates of de-novo mutation and conjugation. These effects depend on the species and biocidal substance. Importantly, chlorhexidine and quaternary ammonium compounds (QACs) affect rates of mutation and conjugation at environmentally relevant concentrations in E. coli. Moreover, our results show a connection between the RpoS-mediated general stress and the RecA-linked SOS response with increased rates of mutation and conjugation, but not for all biocides. Furthermore, our work highlights the potential of biocides to contribute to selection and transmission of AMR. We show that the application of biocides, especially QAC disinfectants, leads to the rapid evolution of tolerance (i.e. increased survival) in adaptive laboratory evolution (ALE) experiments. The evolved tolerant strains have a selective advantage in the presence of environmentally-relevant concentrations of antibiotics, which could lead to the stabilization of biocide tolerance in environments where biocides and antibiotics co-occur (e.g. wastewater, animal stables). ALE experiments with biocide tolerant strains indicate a decreased evolvability of resistance to antibiotics. Taken together, our work shows the importance of assessing the contribution of biocides on evolution, selection and transmission of AMR in the environment.
Human-made systems, also called “build environment” or “technosphere”, sustain human comfort as well as our industrial activities. These systems have become particularly widespread since the Industrial Revolution, i.e., since the 17th century. At the same time, these technical systems – buildings, monuments, energy production, transformation and transmission, water purification and supply systems - serve as new habitats for living organisms.
Life is ubiquitously present on our planet since a very long time: the Earth is 4.54 billion years old and microbial communities have played a key role on our planet for 3.7 billion years. Once human-made system appeared, microorganisms became an integral part of all types of technosphere infrastructure as well.
Here we will illustrate biosphere-technosphere interactions using a specific example of the black fungi and their impact on the efficiency of solar (photovoltaic) panels. This expanding renewable infrastructure for electricity generation is growing on all continents - and create a specific, arid habitat for stress-tolerant black fungi.
Black fungi were once discovered in hot and cold natural deserts – and now belong to the persistent colonisers of human-made deserts of solar parks. This new niche is evolving an impressive biodiversity. So far more than 60 isolates of black fungi belonging to Arthoniomycetes, Eurotiomycetes and Dothideomycetes were obtained from solar panels in Europe and Americas. Here we will present the analysis of this emerging anthropogenic biodiversity.
Opportunities for future research in the field include quantification of the microbial load on technosphere surfaces – along with characterisation of the corresponding microbial diversity. The strategy of precise measurement and characterisation will enable us to reliably determine the beneficial and harmful functions that living microorganisms play in the functioning of energy-generating systems – and technosphere in general.
The aim of the lecture is to present the productive interplay of connoisseurs and material analysis using the example of selected drawings from the Rembrandt collection of the Klassik Stiftung Weimar. We try to determine the point at which the question of the materiality of the drawings makes sense in the traditional discourse of connoisseurship. On the one hand, this involves the question of authorship – Rembrandt – or not? – and the locating of attributed drawings in the context of the work. On the other hand, it is about making drawing processes visible, characterizing ways of drawing and workshop practices as well as distinguishing different forms of reworking and copying within the Rembrandt workshop. The material analyses culminate in the question of whether Rembrandt’s inks can be distinguished at all.
It becomes apparent that the newly gained knowledge about the materiality of the drawing no longer reveals itself to the “mere” view of the connoisseur. Rather, it is only generated by the digital image. The rhetoric of connoisseurs must therefore be contrasted with the necessity of a hermeneutics of the digital image. The envisaged “material turn” of drawing science is thus simultaneously able to take up the critique of the question of authorship, which has been growing ever more recently, and to transfer it to a more comprehensive perspective of aesthetics of production.
The ink analysis protocol developed through cooperation between the Bundesanstalt für Materialforschung und -prüfung in Berlin and the Centre for the Study of Manuscript Cultures at the University of Hamburg involves the use of imaging techniques for ink screening, followed by spectroscopic analysis. In our presentation, we will begin by briefly reviewing the history of writing inks and discussing the three main categories: carbon-based inks, plant, and iron-gall inks. We will address their chronology, precursors, and mixed forms, as well as the features that allow for their identification. Then, we will present the techniques we use in ink analysis, whereby we would like to highlight the limitations, advantages, and disadvantages of each approach. Finally, we will discuss the new mass-spectrometric method based on micro-sampling and using atmospheric solid analysis probe (ASAP).
The Cairo Geniza is an “archive” discovered in the 19th century in Ben Ezra Synagogue in Fustat, a district in Old Cairo (Egypt). The collection of mostly Jewish documents that vary in genres, languages and writing supports contains a large number of early medieval Hebrew manuscripts.
The Geniza provides sources for the literary, linguistic, historical studies of the various aspects Jewish life. As the documents attest, at least two Jewish communities co-existed in Fustat up to 11th century: a so-called Babylonian and Palestinian. These communities had different leaders, different traditions and lived independently. The differences seem to manifest themselves also in the paleographical, codicological and some material properties of the manuscripts produced by each community.
The aim of this project is to compare the inks used in the Jewish documents depending on different variables: support (paper, parchment), purpose of the manuscript (legal, private, religious), provenance of the scribe. For the determination of the inks type and composition we had to choose non-invasive, non-destructive and portable techniques to analyze the corpus directly on-situ.
The analyses were carried out with a micro-X-ray spectrometer ArtTAX® (Bruker GmbH) and a digital stereomicroscope features built-in LED illumination at 395 nm and 940nm, Dino Lite.
We would like to stress that though the methods of material analysis listed above have been successfully employed in the field of cultural heritage and conservation including ancient and medieval manuscripts they have not yet been used to study fragments from the Cairo Genizah. Therefore, we believe that this research project is a pioneering study that will provide new insights into the history of Hebrew writing materials, their production techniques and materials and, thus, contribute new data to the field of Hebrew paleography.
The Cairo Genizah is a well-known “archive” discovered in the 19th century in Ben Ezra Synagogue in Fustat, a district in Old Cairo (Egypt), located south of the center of modern Cairo. The giant collection of mostly Jewish documents that vary in genres, languages and writing supports contains a large number of early medieval Hebrew manuscripts, mostly in fragmentary form. The larger part of the Cairo Genizah is stored today in the Cambridge University Library, containing about 200,000 fragments.
The Genizah provides sources for the literary, linguistic, historical studies of the various aspects Jewish and non-Jewish life. As the documents attest, at least two Jewish communities co-existed in Fustat up to 11th century: a so-called Babylonian and Palestinian. These communities had different leaders, different traditions and lived independently. The differences manifest themselves also in the paleographical properties of the manuscripts produced by each community.
Although Genizah manuscripts have attracted a great deal of scholarly attention, the material aspects of these documents seem to have been largely neglected. The current study aims to obtain information on the composition of the writing supports and the inks used, in order to obtain insights on trade, local production techniques and social structures.
Can we extend the differences detected by the paleographical analysis to differences in composition of the writing materials ? Can we relate the differences in the composition to a community, to the manuscript type (legal, private...), or to another criterion?
X-ray fluorescence analysis, due to its non-destructive nature and ist suitability to work with historic objects in situ, quickly became one of the most important methods for the evaluation of iron-gall ink. The main advantage of this qualitative and semi-quantitative method is that it makes it easy to differentiate between inks, based on the assumption that the differences result from the manufacture of the ink.
This work explores the question whether the ink ‘fingerprint’ results strictly from the elemental composition of the basic ink ingredients even if it is stored in vessels made of metals or metal alloys. In addition, we tested and compared the performance of three different XRF spectrometers.
We prepared various lab-grade inks according to historical ink recipes and measured the metal content of the ink deposited on sized cotton Linters paper with three types of XRF spectrometers: a simple hand-held device with an interaction spot of 4 mm and two devices equipped with poly-capillary Xray optics for line scanning and imaging. Since the exact elemental mass composition of the non-aged ink samples was known, we were able to evaluate the accuracy of the research procedure. Lab-grade inks were then aged in the metal jars imitating inkwells. The aging of the inks in the metal containers resulted in the significant change of the primary inks fingerprint as opposed to that of the control inks stored in glass containers. This effect was independently confirmed by the measurements conducted with every instrument we used. We will present a brief comparison of the results 43 achieved when using different spectrometers and a possible hypothesis explaining the processes that occurred.
Phosphorus (P) fertilizers from secondary resources became increasingly important in the last years. However, these novel P-fertilizers can also contain toxic pollutants. Chromium in its hexavalent state (Cr(VI)) is regulated with low limit values for agricultural products due to its high toxicity, but the determination of Cr(VI) in these novel fertilizer matrices can be hampered by redox processes that lead to false results. Thus, we applied the passive sampler technique Diffusive Gradients in Thin-films (DGT) for the determination of Cr(VI) in fertilizers and compared the results with the standard wet chemical extraction method (German norm DIN EN 15192) and Cr K-edge X-ray absorption near-edge structure (XANES) spectroscopy. We determined an overall good correlation between the wet chemical extraction and the DGT method. DGT was very sensitive and in most cases selective for the analysis of Cr(VI) in P-fertilizers. However, hardly soluble Cr(VI) compounds cannot be detected with the DGT method since only mobile Cr(VI) is analyzed. Furthermore, Cr K-edge XANES spectroscopy showed that the DGT binding layer also adsorbs small amounts of mobile Cr(III) compounds which leads to overestimated Cr(VI) values. The results of certain types of P-fertilizers containing mobile Cr(III) or partly immobile Cr(VI), showed that optimization of the DGT method is required to avoid over- or underestimation of Cr(VI).
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 compatible but also time-consuming method to eradicate insect pests in all kinds of different materials. Treatment results are usually effected 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 several 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 older larvae of Hylotrupes bajulus. However, this species is an unlikely museum pest. Anobiids and other wood boring beetles are more often an issue related to cultural heritage. Tested imbedding materials in general had no mortality lowering influence. A combination of three weeks exposure time at up to 0.5 % residual oxygen and at 24 °C and 50 % RH is recommended for infested artefacts.
Lightweighting as a cross-cutting technology contributes significantly to achieve the European Green Deal goals. Based on, but not limited to, advanced materials and production technologies, the demand for natural resources and CO2 emmissions are reduced by lightweighting during production, as well as use phase. Therefore, lightweighting is a crucial transformation technology assisting in decoupling economic growth from resource consumption. In this manner, lightweighting contributes significantly as a key technology of relevance for many industrial sectors such as energy, mobility, and infrastructure, towards resource efficiency, climate action and economic strength, as well as a resilient Europe. To strengthen international partnerships, addressing global issues of today at the edge of science with high performance lightweight material based on carbon fibers, an overview about the BAM expertise in carbon fiber reinforced materials is given.
The increasing use of carbon fiber reinforced polymers (CFRP), as lightweight materials essential for the transformation, demands for a safe treatment option of carbon fiber (CF) containing waste streams. Because of their low reactivity towards oxidation processes, CF can neither be treated in a conventional nor hazardous waste incineration plant. Even the extremely high temperature in a cement rotary kiln does not lead to full conversion. To increase the sustainability of CF, other processes need to be investigated. Opening other reaction pathways, using CF waste streams as secondary resource in pyrometallurgy to replace fossil carbon, can be a solution for a safe and sustainable treatment. After first small scale experiments, CF containing waste streams were used as reductant in a semi-industrial scale electric arc furnace (EAF). First results and impressions are presented.
The increasing use of carbon fiber reinforced polymers (CFRP), as lightweight materials essential for the transformation, demands for a safe treatment option of carbon fiber (CF) containing waste streams. Because of their low reactivity towards oxidation processes, CF can neither be treated in a conventional nor hazardous waste incineration plant. Even the extremely high temperature in a cement rotary kiln does not lead to full conversion. To increase the sustainability of CF, other processes need to be investigated. Opening other reaction pathways, using CF waste streams as secondary resource in pyrometallurgy to replace fossil carbon, can be a solution for a safe and sustainable treatment. To support the industrial application, experiments on different scales were conducted. Here, results of thermochemical investigations, reactivity studies, crucible experiments and pilot plat trials are reported.
Previous studies have shown that desktop 3D printers (Fused Filament Fabrication) emit high numbers of particulate matter, mainly as ultrafine particles (UFP, particle diameter less than 100 nm). However, the chemical composition of emitted particles has been less extensively investigated. In this study, we therefore focused on the chemical composition of particles emitted from 3D printing. The measurements were conducted in a 1 m³ emission test chamber. Emitted particles were sampled by a 13-stage low-pressure cascade impactor onto aluminum foils and then analyzed by TD-GC/MS to identify their organic compounds. Nine commercial filaments made from basic polymers such as Acrylonitrile Butadiene Styrene (ABS), Acrylonitrile Styrene Acrylate (ASA), Polycarbonate (PC), Poly(methyl methacrylate) (PMMA), Nylon, High Performance Polystyrene (HIPS) and a copper-filled Polylactide (PLA) were investigated. The results show that the organic components of the particles are primarily plastic additives such as plasticizer, antioxidant agents, lubricants, UV-absorbers and UV-stabilizers from the filaments.
In the 15th century, Persian manuscripts underwent significant and lasting changes. Possibly as a response to the import of tinted and gold-decorated paper from China, which was used for manuscript production in Greater Iran, Persian papers were also tinted and embellished with gold-decorated and marbled margins or frames. In a joint project between CSMC and the University of St Andrews, we aim to analyse papers and their decorations in Persian The analyses aim to determine the consistencies of papers, pigments and metals and the techniques used for their production and application. The support will be first described in its codicological characteristics such as dimensions, thickness, colour (expressed in colour coordinates), pattern left from the sieve (observed in transmitted light). The plant used as raw material in paper production will be studied by fibres analysis, while the sizing agents, the pigments, dyes and metals will be analysed by the application of several methods: in particular Reflectography, X-Ray Fluorescence and InfraRed, Raman and Visible Reflectance Spectroscopy. The results of the analyses will form an important resource for the material aspects of Persian manuscripts and be a starting point for establishing a first chronology of the materials and techniques used in Persian manuscript production. An example of the application of the techniques on the analysis of a fragment from a 15th c. Persian Manuscript will be provided.
Recycled fertilizers produced using processes for the recovery of phosphate from residual materials such as wastewater, sewage sludge and sewage sludge ashes show very good bioavailability, but it is still a product largely unknown to the market. The aim of CLOOP is therefore to document the properties and effects of such fertilizers through chemical, mineralogical and ecological analyses as well as analytical method development and pot and field plant growth trials.
Outotec focused on 3 points in CLOOP: Experimental campaigns, process simulations as well as economic analyses with focus on the AshDec process, respectively the design of a large-scale AshDec plant for phosphorus recovery. The laboratory scale trials as well as the semi-industrial scale campaign provided valuable insights into the operating parameters of the process and the plant. As a result, for example, the temperature range could be significantly lowered, and the additive addition reduced by approx. 20 %. They have further shown that the AshDec process is not susceptible to operating fluctuations and that the product can be consistently produced at high quality. With the selection of suitable operating parameters, heavy metals (As, Pb, Cd, (Zn)) can be removed. Within the campaign, about 1.5 t of fertilizer for the plant trials in CLOOP could be produced. An AshDec plant process was digitally created in simulation software, allowing valuable process parameters to be simulated at various operating parameters. On this basis, a full-scale plant was designed. The data obtained in the project were used for a detailed economic analysis including a sensitivity analysis. It was possible to show under which conditions this plant can be operated economically.
At BAM, the AshDec fertilizer was synthesized with different additives and then applied to plant experiments at Uni Bonn. The goal hereby was to check differences in plant uptake. Because of the promising results of AshDec synthesized with sodium-carbonate and because this AshDec version does not require special off gas treatment for sulfur recovery (compared to AshDec synthesized with sodium-sulfate), all project partners agreed on continuing working with this AshDec variation. It was then used as a raw P-source for formulating it into NPK-fertilizers, by granulation with ammonium-sulfate and straw ash as potassium source. These recycling fertilizers were applied to plant- and field experiments by project partners in Brazil (University of Sao Paulo) and Australia (University of Queensland). Furthermore, in leaching experiments, the solubility of phosphorus in AshDec was compared to triple super phosphate. The experiments were carried out on soils with a varying phosphorus buffering index. Results show, that the phosphorus form in AshDec is way less soluble in water. This indicates that AshDec has the potential for a so-called next generation fertilizer – a fertilizer which’s nutrients remain in the soil and supply the plant according to its needs. At the moment, this behavior gets examined more in depth in lysimeter experiments in cooperation with University of Technology Berlin.
The focus of KWB is the Life Cycle Assessment (LCA) of different NextGen fertilizers to evaluate the entire process chain from recovery to fertilizer application. The NextGen fertilizer is credited by the amount of plant available nutrients in the product, which replace nutrients from conventional fertilizer. The LCA covers N-struvite precipitation from municipal wastewater, K-struvite precipitation from industrial wastewater and the AshDec-product from sewage sludge. The LCA task is almost complete. It could be shown that struvite precipitation has comprehensive environmental benefits, mainly since positive side effects occur in sewage sludge treatment (e.g. reduced sludge volume). In principle, the energetic and ecological profile of the AshDec process compared to direct use of sewage sludge ash cannot be assessed as being generally beneficial or negative. Regarding the global warming potential, the Ashdec process shows that the expenses (e.g. energy, chemicals) cannot be covered by the P fertilizer credit. In contrast, the impact categories “terrestrial acidification potential”, and “freshwater eutrophication potential” show positive results as the credits for conventional fertilizer are higher than the burdens for the process.
At University Bonn, the standardized pot experiments were conducted with several AshDec variations, using ryegrass, soybean, and spinach on a slightly acidic sandy soil and an organic-free standard substrate. P-uptake and biomass production of different AshDec variations were generally like those of triple super phosphate and struvite, and clearly outperformed untreated sewage sludge ash and rock phosphate. Field trials in Australia and Brazil with sugarcane on acidic soils are still ongoing and results are expected by the end of 2021.
Per- and polyfluoroalkyl substances (PFAS) are a large group of organofluorine surfactants used in the formulations of thousands of consumer goods. The continuous use of PFAS in household products and the discharge of PFAS from industrial plants into the sewer system have been resulted in contaminated effluents and sewage sludge from wastewater treatment plants (WWTPs) which became an important pathway for PFAS into the environment. Because sewage sludge is often used as fertilizer its application on agricultural soils has been observed as significant input path for PFAS into our food chain. To produce high-quality phosphorus fertilizers for a circular economy from sewage sludge, PFAS and other pollutants (e.g. pesticides and pharmaceuticals) must be separated from sewage sludge. Normally, PFAS are analyzed using PFAS protocols typically with time-consuming extraction steps and LC-MS/MS target quantification. However, for screening of PFAS contaminations in wastewater-based fertilizers also the DGT technique can be used for the PFAS extraction. Afterwards, combustion ion chromatography (CIC) can be applied to analyze the “total” amount of PFAS on the DGT binding layer. The DGT method was less sensitive and only comparable to the extractable organic fluorine (EOF) method values of the fertilizers in samples with >150 µg/kg, because of different diffusion properties for various PFAS, but also kinetic exchange limitations. However, the DGT approach has the advantage that almost no sample preparation is necessary. Moreover, the PFAS adsorption on the DGT binding layer was investigated via surface sensitive spectroscopical methods, such as Fourier-transform infrared (FT-IR) and fluorine K-edge X-ray absorption near-edge structure (XANES) spectroscopy.
While studying the socio-geographic 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. The XRF elemental analysis aims primarily at understanding the fingerprints of inks containing metals, making it possible to distinguish among different inks.
Our own 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). During many years of study, we concluded that the continuous production of Coptic manuscripts from late Antiquity to the Middle Ages offers a unique opportunity for historical study of the ink in a large geographic area. Thanks to the collaboration with the ERC project “PAThs” (www.paths.uniroma1.it), based at the University of Rome La Sapienza, and within the activities of a PhD research dedicated to this topic, we therefore created a new branch of our project focused entirely on the analysis of Coptic inks, pigments, and dyes. This pioneering systematic study of writing materials coming from a specific area and time frame (5th-10th century) aims not only at a better understanding of the complex Coptic multicultural and plurilingual society, but also and mainly at clarifying the links among the Coptic and other societies between the ancient and medieval eras. Finally, it will cast light on the history of the technological development of inks in the eastern world, from Antiquity to the middle ages.
The exposure to antimicrobial substances drives the evolution of antimicrobial resistance. Biocides are antimicrobials used as disinfectants, antiseptics and preservatives. They find application on a large scale in the industrial and medical sector, but also in private households. In terms of mass, the worldwide use of biocides exceeds that of antibiotics. Thus, despite their important role in preventing the spread of pathogens, due to their ubiquity, biocides are suspected to be drivers of the antimicrobial resistance crisis. In our work at BAM we try to understand how biocides contribute to the emergence of AMR, what the underlying adaptation principles and mechanisms are and how they compare to those found for antibiotics. Within our group, I mainly focus on the following two questions: How does phenotypic heterogeneity in bacteria affect the ability to survive treatment with biocides? And what are the consequences of phenotypic heterogeneity for the evolution of resistance to biocides and antibiotics?
I will share published and unpublished results which demonstrate that phenotypic heterogeneity can enable the survival of biocide treatment and, through this, facilitate the evolution of AMR. On the other hand, we find that adaptation to a biocide can unexpectedly impair the ability to evolve resistance against an antibiotic.