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Organisationseinheit der BAM
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Das Element Phosphor ist für Pflanzen, Tiere und Menschen essenziell. Um die Phosphorversorgung für Pflanzen in der Landwirtschaft zu gewährleisten, werden Phosphordünger eingesetzt. Die Nährstoffe werden hauptsächlich durch Wirtschaftsdünger (Gülle, Jauche, Stallmist) zurückgeführt. Zusätzlich werden in der konventionellen Landwirtschaft mineralische Phosphordünger eingesetzt, die vorwiegend aus dem fossilen Rohstoff Phosphorit gewonnen werden. Um die Abhängigkeit von fossilen Rohstoffen zu reduzieren, sollen nährstoffhaltige Rest- und Abfallstoffe zur Phosphordünger aufbereitet werden. In Abwasserkläranlagen fällt phosphorreicher Klärschlamm als Abfallstoff an. Der größte Anteil des Klärschlammes wird in Steinkohlekraftwerken, Zementwerken oder in Monoklärschlammverbrennungsanlagen verbrannt. Die Klärschlammaschen aus den Monoverbrennungsanlagen enthalten bis zu 12 Gew.-% Phosphor und sind daher für die Düngerherstellung geeignet.
Ein geeignetes Verfahren zur Aufbereitung der Klärschlammaschen ist die thermochemische Behandlung im Drehrohrofen. Mit dem sogenannten AshDec®-Prozess, kann ein Phosphordünger hergestellt werden. Aktuell wird eine großtechnische Anlage in Altenstadt (Bayern) geplant, die im Jahr 2023 den Betrieb aufnehmen soll. Der zentrale Bestandteil ist die Phasenumwandlung von schlecht pflanzenverfügbaren Phosphaten in der Klärschlammasche (vorwiegend das Calciumphosphat Whitlockit und Aluminiumphosphat) zu gut pflanzenverfügbaren Calciumalkaliphosphaten im Produkt. Um dies zu erzielen, werden die Aschen mit Natrium- und/oder Kalium-Verbindungen gemischt und einer thermochemischen Behandlung bei 800-1000 °C zugeführt. Um die Pflanzenverfügbarkeit und Düngewirkung von Phosphaten abschätzen zu können, ist die chemische Extraktionsmethode mit neutraler Ammoniumcitratlösung geeignet.
In der Dissertation werden die (Phosphor-)Phasenreaktionen und die Prozessbedingungen des thermochemischen Verfahrens untersucht, um das Verfahren gezielt zu modifizieren und die Wirtschaftlichkeit zu steigern. Die Zielphasen der thermochemischen Behandlung sind die Calciumalkaliphosphate CaNaPO4 und CaKPO4, und deren Mischphasen Ca(Na,K)PO4, welche in der Publikation 3.1 synthetisiert wurden. Für diese Calciumalkaliphosphate wurden die thermodynamischen Daten der Standardbildungsenthalpie, Standardentropie, Wärmekapazität und die Wärmemenge der Phasenumwandlung bestimmt (Publikation 3.1).
Bei der thermochemischen Behandlung von Klärschlammaschen wurden als Additive Natrium- und Kaliumsulfat bei verschiedenen Temperaturen getestet. Der Einsatz von Kaliumadditiven ist erwünscht, um den Marktwert des Produktes durch die Produktion eines Phosphor-Kalium-Düngers zu erhöhen. Zusätzlich wird eine möglichst geringe Prozesstemperatur angestrebt, bei der die erwünschten Calciumalkaliphosphate gebildet werden.
In den Publikationen 3.2 und 3.3 wird gezeigt, dass für Klärschlammaschen eine komplette Phasenumwandlung zu Calciumnatriumphosphaten ab 875 °C in Laborversuchen (Korundtiegel) mit dem Additiv Natriumsulfat erzielt werden kann. Der Einsatz von Kaliumsulfat erforderte notwendige Reaktionstemperaturen von über 1100 °C. Diese
unterschiedlichen Reaktionstemperaturen hängen mit den Schmelzpunkten von Natriumsulfat (890 °C) und Kaliumsulfat (1070 °C) zusammen. Um Kaliumsulfat in den Prozess bei niedrigen Temperaturen zu integrieren, wurden Natriumsulfat und Kaliumsulfat vor der Behandlung gemischt. Dies führte zu einer Schmelzpunkterniedrigung und resultierte in Reaktionstemperaturen zwischen 900 °C bis 1000 °C für die untersuchten Mischungen von Natrium- und Kaliumsulfat (Publikation 3.3).
Die Zusammensetzung der Calciumalkaliphosphate Ca(Na,K)PO4 war anders als erwartet. Bei der Phasenanalytik stellte sich heraus, dass bei geringem und mittlerem Anteil von Kaliumsulfat im Alkali-Additiv nur Calciumnatriumphosphate mit sehr geringen Kaliumgehalten gebildet wurden. Erst bei einem hohen Anteil von Kaliumsulfat in der Mischung der Alkalisulfate konnten kaliumhaltige Calciumalkaliphosphate nachgewiesen werden (u.a. (Ca0.9Mg0.1)(Na0.6K0.4)PO4). Dieser geringere Einbau von Kalium in die Calciumalkaliphosphate hängt mit den zusätzlich stattfindenden Reaktionen zwischen den Alkalien und den Silikaten zusammen. Es ist bekannt, dass die zugegebenen Alkalisulfate zuerst mit Silikaten und anschließend mit den Phosphaten reagieren. Silikate bauen bevorzugt Kalium ein, deswegen konnten erst kaliumhaltige Phosphate gebildet werden, wenn die Reaktion mit den Silikaten abgeschlossen war. Dies führte zu einem geringeren Kaliumanteil in den gebildeten Phosphaten im Vergleich zum Kaliumanteil der verwendeten Alkaliadditive. Das in Silikaten gebundene Kalium ist wahrscheinlich schlecht für die Pflanzen verfügbar. Dies könnte den Einsatz der produzierten Phosphor-Kalium-Dünger einschränken. Der bevorzugte Kaliumeinbau in Silikaten konnte auch in Kalkulationen mit den thermodynamischen Daten aus der Publikation 3.1 gezeigt werden.
Mittels Phasenanalytik vor und nach der chemischen Extraktion, konnte die Zugehörigkeit zu verschiedenen Modifikationen der Calciumalkaliphosphaten sicher bestimmt werden und eine ungefähre Zusammensetzung dieser Calciumalkaliphosphate abgeschätzt werden. So konnte nachgewiesen werden, dass die Modifikation vom CaNaPO4 ungefähr 10 % Magnesium einbauen kann. Wenn mehr Magnesium eingebaut wird, bildet sich die Phase (Ca,Mg)NaPO4, die eine vergleichbare Struktur wie die bekannte Phase (Ca0.72Mg0.28)NaPO4 aufweist. Dieses magnesiumreiche Calciumnatriumphosphat entstand vermutlich, wenn entweder erhöhte Anteile an Kalium eingebaut wurden (Ca0.8Mg0.2)(Na0.85K0.15)PO4 (Publikation 3.3) oder die Phasenumwandlung vom Calciumphosphat Whitlockit zum Calciumalkaliphosphat CaNaPO4 noch nicht abgeschlossen war (Publikation 3.2). Wenn mehr Kalium eingebaut wird, dann entsteht eine Phase (u.a. (Ca0.9Mg0.1)(Na0.6K0.4)PO4) ähnlich zu den Mischphasen aus der Publikation 3.1.
In den Publikationen 3.4 und 3.5 wurden keine Klärschlammaschen untersucht, sondern Biokohlen aus Modellklärschlämmen (Publikation 3.5) und Biomasseaschen (Publikation 3.4) aus der Vergasung oder Verbrennung einer Mischung aus Zuckerrohrbagasse und Hühnertrockenkot. Die thermochemischen Produkte der Biokohlen bzw. Biomasseaschen enthielten das gewünschte CaNaPO4 und hatten eine hohe Düngewirkung in Pflanzenwachstumsversuchen mit Sojapflanzen bzw. Gräsern.
This work presents a spectroscopic study of metallic pigments and metal foils used in reverse glass paintings that were created between 1912 and 1954. Metallic pigments induce a notable sparkling effect by means of the lateral incidence of light, whereas metal foils enhance the gloss and create a glittering effect when the painting is viewed in reflected light. Both effects were desired features especially in modern reverse paintings on glass and applied by artists in manifold creative manner. The paper gives an overview on the composition of the metalfoils and metal pigments in 14 works as determined in situ by X-ray spectrometry. Metal foils made of tin, brass, aluminium and silver were found in nine paintings. Gold imitating Cu-Zn pigments in different hues and with various Cu/Zn net intensity ratios were recorded for six paintings. Silvery pigments were identified mainly as Al pigments, but also as Cu-Zn-Ni alloy in one case. Other uncommon metallic pigments were detected in Arlequin vindicatif (c. 1925) by Floris Jespers, who used not only Cu-Zn and Al pigments, but also brownish Cu and Cu-Zn-Sn pigments. Non-invasive diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) was used to classify the binding media of the metallic pigments. Drying oil and natural resin probably mixed with oil were the most common binding media. A polysaccharide-based binder was found in the silvery Cu-Zn-Ni pigment of Ohne Titel (1954) by Marianne Uhlenhuth.
The Scythica Vindobonensia, the new fragments on Gothic incursions into Roman provinces in the Balkans in the middle of the third century AD that were revealed some years ago in a Greek palimpsest at the Austrian National Library in Vienna (ÖNB), are commonly considered as one of the most important additions of the last decades to the corpus of texts from classical Antiquity. Tere is a high degree of confdence among scholars in supposing that the fragments come from the lost work Scythica written in Greek by the third-century historian P. Herennius Dexippus (Δέξιππος) of Athens. The new fragments have hence also been called Dexippus Vindobonensis. In his Scythica, Dexippus recorded wars of the Romans with the Goths (and other tribes) whom he called Scythians.
The work had been hitherto known only from excerpts and quotes by later authors. Eight pages of a Byzantine manuscript copy of the ancient text have survived hidden underneath the visible surface of the last four parchment folios of the Vienna manuscript Historicus graecus 73, f. 192r -195v4. The copy is written in a Greek calligraphic minuscule which has been estimated by palaeographers to be of the middle or the second half of the eleventh century. In the thirteenth century, the text (on each of the eight pages arranged in one column, with 30 lines per page) was washed of the parchment and the valuable material made from animal skin was re-used for Christian texts. The new writing largely covered the faded remnants of the original text. It thus became hidden from the human eye for more than seven hundred years. Its discovery by Jana Grusková, a classical philologist specialized in the transmission of Greek texts, resulted from a systematic review of all Greek palimpsests kept at the Austrian National Library in Vienna at the beginning of the twenty-first century and a detailed examination of the four folios in 2007-20097.
With the advent of widely accessible and cost-effective next-generation sequencing technologies, it has become increasingly feasible to study insect immunity on a deep genomic or transcriptomic level. Here we introduce a protocol that is aimed at exploiting transcriptomic data to study immunity in non-model insect organisms. We provide instructions for an entire workflow, starting with successfiil extraction of insect RNA through to bioinformatic guidelines for the effective analysis of mRNA sequencing data. The RNA extraction procedure is based on TRIzol Reagent and a spin-column clean-up Step. The bioinformatic pipeline is intended to help users identify immune genes from de novo transcriptome data and includes guidelines for conducting differential gene expression analyses on transcriptomic data. The immune gene prediction method is based on inferring protein homologs with HMMERand Blastp and talces Advantage ofthe ImmunoDB database, which is a valuable resource for research on insect immune-related genes and gene families. The differential gene expression analysis procedure utilizes the DESeq2 package as implemented in R. We hope this protocol will serve as a usefi.il resource for researchers aiming to study immunity in non-model insect species.
The scribe of ‘Erfurt 7’, a thirteenth-century Torah scroll now kept in Berlin, initially left blank spaces for the divine appellations Elohim ( אלהים ) and YHWH Elohim ( ,(יהוה אלהים which were filled in during a second stage of writing. The appearance of the ink employed to write the appellations was significantly darker than that of the surrounding ink.
X-ray fluorescence analysis (XRF) has shown that the light and dark brown inks had similar elemental compositions, but contained different ratios of iron to potassium, which could be explained by the use of different batches of ink.
According to some medieval sources, the divine appellations were sometimes filled in during a second stage of writing in the presence of ten men from the Jewish community. In Erfurt 7, the two-stage procedure was only performed in the first 1.5 columns of the original sheets, suggesting it may have been part of a public ceremony inaugurating the writing of the divine names in the scroll. Erfurt 7 emerges from this study not only as a ritual object used for liturgy, but as a rallying point for the Jews of Erfurt to come together as a community to express their reverence for the written form of God’s name. The divine name YHWH ( יהוה ) was written in a smaller script than the surrounding text on three replacement sheets using the same two-stage procedure. The ink used on the replacement sheets contained zinc, which is characteristic of other Erfurt manuscripts as well. This suggests that Erfurt was the place where the scroll was used, cherished and eventually repaired.
There are viral, fungal, bacterial and trypanosomal pathogens that negatively impact the individual and superorganismal health of the western honey bee. One fungal pathogen, Ascosphaera apis , affects larvae and causes the disease chalkbrood. A previous genome analysis of As. apis revealed that its genome encodes for RNA interference genes, similar to other fungi and eukaryotes. Here, we examined whether As. apis -targeting double-stranded RNA species could disrupt the germination of As. apis.
We observed that when spores were co-incubated with As. apis -targeting dsRNA, fewer spores were activated for germination, suggesting an uptake of exogenous genetic material at the very onset of germination and consequent damage to essential transcripts needed for germination. Overall, these results indicate that the causative agent of chalkbrood disease, As. apis , can be successfully targeted using an RNAi-based strategy.
The paper presents the results of the radiocarbon dating and ink analysis of a leather fragment bearing an important liturgical text in Hebrew from the early centuries of the common era. The work initiated by the scholarly interest in the text stresses the importance of the date and materiality of the manuscripts and closes with an appeal to the curators of manuscript collections.
Monodisperse iron oxide nanoparticles as reference material candidate for particle size measurements
(2020)
In order to utilize and rationally design materials at the nanoscale the reliable characterization of their physico-chemical properties is highly important, especially with respect to the assessment of their environmental or biological impact. Furthermore, the European Commission’s REACH Regulations require the registration of nanomaterials traded in quantities of at least 1 ton. Powders or dispersions where 50% (number distribution) of the constituent particles have sizes ≤ 100 nm in at least one dimension are defined as nanomaterials. This creates a need for industrial manufacturers and research or analytical service facilities to reliably characterize potential nanomaterials. Currently, BAM is developing reference nanoparticles, which shall expand the scarce list of worldwide available nano reference materials certified for particle size distribution and will also target other key parameters like shape, structure, porosity or functional properties. In this respect, materials like iron oxide or titanium dioxide are considered as candidates to complement the already available silica, Au, Ag, and polystyrene reference nanoparticles.
The thermal decomposition of iron oleate precursors in high boiling organic solvents can provide large quantities of iron oxide nanoparticles that can be varied in size and shape.[1, 2] The presence of oleic acid or other hydrophobic ligands as capping agents ensures stable dispersion in nonpolar solvents. Such monodisperse, spherical particles were synthesized at BAM and pre-characterized by electron microscopy (TEM, SEM including the transmission mode STEM-in-SEM) and dynamic light scattering comparing cumulants analysis and frequency power spectrum.
1. REACH regulations and nanosafety concerns create a strong need for nano reference materials with diverse properties.
2. Iron oxide nanoparticles are under development as new candidate reference material at BAM.
3. Narrow particle size distribution confirmed by light scattering and electron microscopy.
Based on recently published research on leaching control mechanisms in electric arc furnace (EAF) slags, it is assumed that a FeO/SiO2 ratio of around one leads to low leached V and Cr concentrations. This ratio influences the mineral phase composition of the slag toward higher amounts of spinel and a lower solubility of calcium silicate phases by suppressing the formation of magnesiowuestite and highly soluble calcium silicate phases. To evaluate this hypothesis, laboratory and scaled up tests in an EAF pilot plant were performed on slag samples characterized by elevated V and Cr leaching and a high FeO/SiO2 ratio. Prior to the melting experiments, the optimum FeO/SiO2 ratio was calculated via FactSageTM. In the melting experiments, the ratio was adjusted by adding quartz sand, which also decreased the basicity (CaO/SiO2) of the slag. As a reference, remelting experiments without quartz sand addition were conducted and additionally, the influence of the cooling rate of the slag was examined. The remelted (without quartz sand) and the remelted modified slags (with quartz sand) were analyzed chemically and mineralogically and the leaching behavior was investigated. The modification of the slags yielded a minimized release of V and Cr, supporting the hypothesis that the FeO/SiO2 ratio influences the mineralogy and the leaching behavior.
Salt tolerance in the γ-proteobacterium Halomonas elongata is linked to its ability to produce the compatible solute ectoine. The metabolism of ectoine production is of great interest since it can shed light on the biochemical basis of halotolerance as well as pave the way for the improvement of the biotechnological production of such compatible solute. Ectoine belongs to the biosynthetic family of aspartate-derived amino-acids. Aspartate is formed from oxaloacetate, thereby connecting ectoine production to the anaplerotic reactions that refill carbon into the tricarboxylic acid cycle (TCA cycle). This places a high demand on these reactions and creates the need to regulate them not only in response to growth but also in response to extracellular salt concentration. In this work, we combine modeling and experiments to analyze how these different needs shape the anaplerotic reactions in H. elongata. First, the stoichiometric and thermodynamic factors that condition the flux distributions are analyzed, then the optimal patterns of operation for oxaloacetate production are calculated. Finally, the phenotype of two deletion mutants lacking potentially relevant anaplerotic enzymes: phosphoenolpyruvate carboxylase (Ppc) and oxaloacetate decarboxylase (Oad) are experimentally characterized. The results show that the anaplerotic reactions in H. elongata are indeed subject to evolutionary pressures that differ from those faced by other gram-negative bacteria. Ectoine producing halophiles must meet a higher metabolic demand for oxaloacetate and the reliance of many marine bacteria on the Entner-Doudoroff pathway compromises the anaplerotic efficiency of Ppc, which is usually one of the main enzymes fulfilling this role. The anaplerotic flux in H. elongata is contributed not only by Ppc but also by Oad, an enzyme that has not yet been shown to play this role in vivo. Ppc is necessary for H. elongata to grow normally at low salt concentrations but it is not required to achieve near maximal growth rates as long as there is a steep sodium gradient. On the other hand, the lack of Oad presents serious difficulties to grow at high salt concentrations. This points to a shared role of these two enzymes in guaranteeing the supply of oxaloacetate for biosynthetic reactions.
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.
Popioły pochodzące z instalacji do spalania komunalnych osadów ściekowych, znajdującej się na terytorium Polski, poddano procesom termochemicznego przekształcania, dzięki czemu otrzymano produkty nawozowe spełniające kryteria dopuszczające je do obrotu jako nawozy mineralne. Ponadto dokonano analizy możliwości wykorzystania popiołów na cele nawozowe zgodnie z obecnie przyjętymi dokumentami strategicznymi i planistycznymi dotyczącymi gospodarki odpadami na poziomie krajowym i europejskim.
The potential release of hazardous substances from polymer-based products is currently in the focus of environmental policy. Environmental simulations are applied to expose such products to selected aging conditions and to investigate release processes. Commonly applied aging exposure types such as solar and UV radiation in combination with water contact, corrosive gases, and soil contact as well as expected general effects on polymers and additional ingredients of polymer-based products are described. The release of substances is based on mass-transfer processes to the material surfaces. Experimental approaches to investigate transport processes that are caused by water contact are presented. For tailoring the tests, relevant aging exposure types and release quantification methods must be combined appropriately. Several studies on the release of hazardous substances such as metals, polyaromatic hydrocarbons, flame retardants, antioxidants, and carbon nanotubes from polymers are summarized exemplarily. Differences between natural and artificial exposure tests are discussed and demonstrated for the release of flame retardants from several polymers and for biocides from paints. Requirements and limitations to apply results from short-term artificial environmental exposure tests to predict long-term environmental behavior of polymers are presented.
Der Verwertung von Bodenmaterialien wird auf Grund des Volumens dieses Stoffstromes eine hohe umweltpolitische Bedeutung beigemessen. Dabei ist unter Gewährleistung des Vorsorge- und Nachhaltigkeitsprinzips eine möglichst hochwertige Verwertung anzustreben, um natürliche Ressourcen zu schonen und die Beseitigung von Abfällen weitestgehend zu vermeiden.
Die vorgesehene Novelle der BBodSchV enthält in den Paragraphen 6 bis 8 neue Vorgaben hinsichtlich des Auf- und Einbringens von Bodenmaterialien unterhalb oder außerhalb einer durchwurzelbaren Bodenschicht. So soll die Möglichkeit eingeräumt werden, Bodenmaterialien mit Feststoffgehalten von regulierten Stoffen zwischen dem einfachen und doppelten Vorsorgewert einer weiteren Verwertung zuzuführen unter der Voraussetzung, dass die Eluatwerte eingehalten werden.
Im Rahmen eines Forschungsvorhabens des Umweltbundesamtes (FKZ: 3716 74 203 0) wurden unterschiedliche Bodenmaterialien (Baggergut, Bankettschälgut, Stadt- und Auenböden, Bergematerial), die unter diese Kriterien fallen, mit besonderem Fokus auf PAK hinsichtlich ihres Verwertungspotentials untersucht.
Dabei wurden auch die Auswirkungen der Umstellung des Elutionsverfahrens von einem Wasser-Feststoffverhältnis (W/F) von 10 l/kg auf ein W/F von 2 l/kg auf die Einstufung von Bodenmaterialien betrachtet.
Insbesondere für die Stoffgruppe der PAK konnte gezeigt werden, dass sich mit Verabschiedung der neuen Regelungen zusätzliche Verwertungsmöglichkeiten von Bodenmaterialien außerhalb der durchwurzelbaren Bodenschicht eröffnen und deren Deponierung teilweise vermieden werden kann.
Antimicrobial touch surfaces have been introduced in healthcare settings with the aim of supporting existing hygiene procedures, and to help combat the increasing threat of antimicrobial resistance. However, concerns have been raised over the potential selection pressure exerted by such surfaces, which may drive the evolution and spread of antimicrobial resistance. This review highlights studies that indicate risks associated with resistance on antimicrobial surfaces by different processes, including evolution by de-novo mutation and horizontal gene transfer, and species sorting of inherently resistant bacteria dispersed on to antimicrobial surfaces. The review focuses on antimicrobial surfaces made of copper, silver and antimicrobial peptides because of the practical application of copper and silver, and the promising characteristics of antimicrobial peptides. The available data point to a potential for resistance selection and a subsequent increase in resistant strains via cross-resistance and co-resistance conferred by metal and antibiotic resistance traits. However, translational studies describing the development of resistance to antimicrobial touch surfaces in healthcare-related environments are rare, and will be needed to assess whether and how antimicrobial surfaces lead to resistance selection in These settings. Such studies will need to consider numerous variables, including the antimicrobial concentrations present in coatings, the occurrence of biofilms on surfaces, and the humidity relevant to dry-surface environments. On-site tests on the efficacy of antimicrobial Coatings should routinely evaluate the risk of selection associated with their use.
Dem Fachbeirat Bodenuntersuchungen des BMBF/UBA wurden die abschließenden Ergebnisse zum UFOPLAN-Forschungsvorhaben „Monitoring zur Verwertung von Bodenmaterial“ vorgestellt. Die potentielle Auswirkung der neuen Regularien in der geplanten Novelle der BBodSchV (4. Referentenentwurf der Mantelverordnung) auf die Erweiterung der Verwertungsmöglichkeiten von Bodenmaterialien wurden aufgezeigt.
How the rock-inhabiting fungus K. petricola A95 enhances olivine dissolution through attachment
(2020)
Free-living and mycorrhizal fungi are able to enhance the weathering of rock and other solid substrates. Deciphering the exact mechanisms of these natural processes requires their experimental simulation. Moreover, by performing these simulations with genetically amenable rock-weathering fungi, one can knock-out certain fungal traits and consequently identify their weathering-relevant function. Here, the effect of the rock-inhabiting fungus, Knufia petricola A95, on the dissolution kinetics of an Fe-bearing olivine (Mg1.86Fe0.19SiO4) is investigated at 25 °C and pH 6 using reproducible batch and mixed flow experiments. The availability of a melanin-deficient mutant (ΔKppks) of K. petricola A95, which produces more extracellular polymeric substances (EPS) than the wild type (WT), enables the comparative study of the role of melanin and EPS in olivine dissolution. In abiotic dissolution experiments, the olivine dissolution rate decreased considerably over time at pH 6 but not at pH 3.5. This inhibition of abiotic olivine dissolution at pH 6 was most likely caused by the in-situ oxidation of ferrous Fe and/or the precipitation of ferric hydroxides at the olivine surface. In corresponding biotic experiments at pH 6, both the wild type K. petricola and its melanin-deficient mutant ΔKppks solubilised and bound significant amounts of Fe released by olivine dissolution. Fe oxidation and precipitation were thus prevented and olivine dissolution proceeded faster than in the abiotic experiments. By sequestering Fe directly at the olivine surface, the attached wild type K. petricola cells were particularly efficient at preventing the oxidation of Fe at the mineral surface: the slowdown of olivine dissolution almost completely disappeared. The attachment capacity of these wild type cells is most likely mediated by wild type-specific EPS. Our presented experimental systems allow the oxidation of mineral-released Fe and include a rock-inhabiting fungus, thus simulating chemical, physical and biological conditions that set dissolution rates in a way that is relevant to natural ecosystems.
In many bacteria, the biofilm-promoting second messenger c-di-GMP is produced and degraded by multiple diguanylate cyclases (DGC) and phosphodiesterases (PDE), respectively. High target specificity of some of these enzymes has led to theoretical concepts of "local" c-di-GMP signaling. In Escherichia coli K-12, which has 12 DGCs and 13 PDEs, a single DGC, DgcC, is specifically required for the biosynthesis of the biofilm exopolysaccharide pEtN-cellulose without affecting the cellular c-di-GMP pool, but the mechanistic basis of this target specificity has remained obscure. DGC activity of membrane-associated DgcC, which is demonstrated in vitro in nanodiscs, is shown to be necessary and sufficient to specifically activate cellulose biosynthesis in vivo. DgcC and a particular PDE, PdeK (encoded right next to the cellulose operon), directly interact with cellulose synthase subunit BcsB and with each other, thus establishing physical proximity between cellulose synthase and a local source and sink of c-di-GMP. This arrangement provides a localized, yet open source of c-di-GMP right next to cellulose synthase subunit BcsA, which needs allosteric activation by c-di-GMP. Through mathematical modeling and simulation, we demonstrate that BcsA binding from the low cytosolic c-di-GMP pool in E. coli is negligible, whereas a single c-di-GMP molecule that is produced and released in direct proximity to cellulose synthase increases the probability of c-di-GMP binding to BcsA several hundred-fold. This local c-di-GMP signaling could provide a blueprint for target-specific second messenger signaling also in other bacteria where multiple second messenger producing and degrading enzymes exist.
Gegenstand dieser Arbeit ist die Untersuchung eines bestehenden pyrometallurgischen Prozesses zur Rückgewinnung von Tantal und Niob aus metallurgischen Reststoffen mit vorwiegend niedriger Wertstoffkonzentration.
Zur näheren Erforschung der im vorliegenden Stoffsystem ablaufenden Reduktionsprozesse wurden in einem Elektrolichtbogenofen Schmelzversuche im Pilotmaßstab durchgeführt. Als Reduktionsmittel diente Koks, welcher mithilfe einer Argon-gespülten Eisenlanze in die flüssige mineralische Schmelze eingebracht wurde. Während der Reduktionsbehandlung werden Refraktärmetalle wie Tantal und Niob in ihre Carbide überführt und anschließend in der erschmolzenen eisenbasierten Metallphase am Boden des Reaktors angereichert. Neben Tantal und Niob gelangt auch ein Teil des im Einsatzmaterial enthaltenen Titans als unerwünschtes Begleitelement in die Metallphase.
Sein Großteil verbleibt jedoch als Oxid in der Schlacke und wird dort hauptsächlich im Mineral Perowskit (CaTiO3) gebunden. Die erstarrten Schlackeproben wurden mit verschiedenen Methoden wie Röntgenfluoreszensanalyse, Röntgenbeugung und Rasterelektronenmikroskopie mit gekoppelter energiedispersiver Röntgenanalyse untersucht, um die Bildung tantalhaltiger Mineralphasen zu verschiedenen Stadien des Reduktionsprozesses zu verfolgen.
Die hier gewonnenen Erkenntnisse zeigen, dass weniger die durch das Einblasen von Koks verursachte Reduktionsreaktion, sondern das Absinken der tantalreichen Eisentröpfchen in der flüssigen mineralischen Schmelze, gefolgt von ihrer Anreicherung in die Metallphase, für die Kinetik ausschlaggebend ist.
This paper presents an inventory of sewage sludge ashes (SSA) generated in the mono-incineration plants for municipal sewage sludge in Poland. This research focused on the detailed study of mass flows, chemical composition, and phosphorus recovery potential. There are currently 11 sludge mono-incineration plants operated with a total capacity of 160,300 Mg dry weight (d.w.) of sludge annually. Recently, a significant increase in the amount of SSA generated in these plants has been observed, reaching 26,756 Mg in 2018. Chemical composition of SSA showed significant amounts of the main nutrients: calcium (~14%), phosphorus (~13%), magnesium (~3%), and potassium (~1%). Additional main elements were iron (~14.5%), silicon (~13%), and aluminium (~6%). The main trace elements in the SSA were zinc (~3750 mg/kg) and copper (~899 mg/kg). Pollutants, according to fertilizer regulations of different countries, present in Polish SSA were chromium(~703 mg/kg), nickel (~260 mg/kg), lead (~94 mg/kg), and Cadmium (~9 mg/kg). The radionuclides, uranium, and thorium often present in higher amounts in commercial phosphate rock-based fertilizers, were only detected in SSA t low levels of 4–9 mg/kg and 2–3 mg/kg, respectively. Theoretical phosphorus recovery potential from the SSA (from plants in Cracow, Lodz, Gdansk, Gdynia, Szczecin, and Kielce) was estimated at 1613.8 Mg, of which 33.9% is bioavailable. Currently, in Poland, the recommended approach is the production of fertilizers as a result of the extraction of phosphorus from the SSA with its use in the production of secondary mineral fertilizers.
Further research in this area is required considering Polish conditions and legislation.
This study investigated the adaptation of the state-of-the-art test procedure for the determination of emissions of volatile organic compounds (VOC) from materials into indoor air to test for the radon exhalation from stony construction products. A complete robustness validation including all relevant parameters showed that the procedure can be well applied by testing institutes already holding available the required VOC testing infrastructure that solely needs to be complemented by calibrated commercial radon measurement instrumentation. When measurements of the radon exhalation from construction materials become mandatory by law, test capacity can easily be applied. This work can serve as a recommendation for the European standardisation that still is on hold in this point.
The reliable measurement of very volatile organic compounds (VVOC) in indoor air by use of thermal desorption gas chromatography (TD-GC) in order to include them into evaluation schemes for building products even nowadays is a great challenge. For capturing these small molecules with carbon numbers ranging from C 1 –C 6 , strong adsorbents are needed. In the present study, recovery rates of nine suitable adsorbents of the groups of porous polymers, graphitised carbon blacks (GCB) and carbon molecular sieves (CMS) are tested against a complex test gas standard containing 29 VVOC. By consideration of the recovery and the relative humidity (50% RH), combinations of the GCB Carbograph 5TD, the two CMS Carboxen 1003 and Carbosieve SII as well as the porous polymer Tenax® GR were identified to be potentially suitable for sampling the majority of the VVOC out of the gas mix. The results reveal a better performance of the adsorbents in combination than being used alone, particularly under humid sampling conditions. The recovery rates of the chosen compounds on each adsorbent should be in the range of 80–120%.
The growth rate of single bacterial cells is continuously disturbed by random fluctuations in biosynthesis rates and by deterministic cell-cycle events, such as division, genome duplication, and septum formation.
It is not understood whether, and how, bacteria reject these growth-rate disturbances. Here, we quantified growth and constitutive protein expression dynamics of single Bacillus subtilis cells as a function of cell-cycle progression. We found that, even though growth at the population level is exponential, close inspection of the cell cycle of thousands of single Bacillus subtilis cells reveals systematic deviations from exponential growth.
Newborn cells display varying growth rates that depend on their size. When they divide, growth-rate Variation has decreased, and growth rates have become birth size independent. Thus, cells indeed compensate for growth-rate disturbances and achieve growth-rate homeostasis. Protein synthesis and growth of single cells displayed correlated, biphasic dynamics from cell birth to division. During a first phase of variable duration, the absolute rates were approximately constant and cells behaved as sizers. In the second phase, rates increased, and growth behavior exhibited characteristics of a timer strategy. These findings demonstrate that, just like size homeostasis, growth-rate homeostasis is an inherent property of single cells that is achieved by cell-cycle-dependent rate adjustments of biosynthesis and growth.
This thesis addresses the development of a methodological approach for the non-invasive identification of colourants and for the classification of binding media in reverse glass paintings from the early 20th century. For this purpose, mobile and miniaturized devices were used to measure the paintings in situ. The methodology includes X-ray fluorescence (XRF), VIS spectroscopy (VIS), Raman spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). In a first step the capabilities of DRIFTS for binding media classification and pigment identification were tested.
DRIFTS enables, besides Raman spectroscopy, the collection of molecular information of a substance that can be used as characteristic fingerprint spectrum. However, the simultaneous collection of both specular (surface) and diffuse (volume) reflection leads to complicated mixed DRIFT spectra, that can vary strongly for one substance depending on the dominant fraction of reflected light. Specular reflection causes several spectral distortions like inverted bands, band shifts and derivative-like features whereas pure diffuse reflections leads to an intensity enhancement of combination bands and overtones. Both specular and diffuse reflection cannot be optically separated, and their proportion depends on material properties like the absorption coefficient and the refractive index as well as on Parameters like surface roughness, porosity, grain size and angle of incidence and detection. A direct comparison of DRIFT spectra with IR spectra of other methods (e.g. transmission, ATR) is not possible, hence the creation of DRIFTS databases was needed. The next step was the complimentary utilization of Raman spectroscopy and DRIFTS for the dentification of synthetic organic colourants. Such colourants are in the further chapters called synthetic organic pigments (SOP) even when it’s not always entirely clear if they are soluble dyes or pigments that are practically insoluble in the medium in which they are incorporated. Raman spectroscopy is generally the method of choice when dealing with SOP, but fluorescence can hamper the Raman spectrum severely, inhibiting the proper identification of the pigment.
DRIFTS was successfully applied and several SOP like synthetic alizarin (PR83), the yellow azo pigments (e.g. PY1) or the red and orange β-naphthol pigments (e.g. PR3) could be identified in the paintings solely by means of DRIFTS. The holistic methodological sequence was defined after the successful establishment of DRIFTS as serious analytical alternative. As the time is always the most limiting factor for in situ measurement campaigns in museums, the 9
sequence needs to be time saving but also efficient. The methodology starts with quick measurements by XRF and VIS to get a first idea of the pigment composition, followed by the validation of the results with the vibrational spectroscopies for selected points.
Measurements of reverse glass paintings by Carlo Mense and Wassily Kandinsky were conducted to test the entire procedure. A high number of pigments could be identified, including several rare ones like strontium white (SrSO4), PR60 and PB52. The binding media were classified using the previously recorded references. The results were set in the art historian context and were discussed in a multidisciplinary way. The influence of Asian art, especially of Chinese reverse glass paintings as source of inspiration for artists of the “Blauer Reiter” collective (e.g. Wassily Kandinsky, Gabriele Münter, Franz Marc und Heinrich Campendonk) is shown. Non-invasive measurements of two Chinese reverse glass paintings from the late 19th and early 20th century were conducted, enabling a comparison of the palettes of Chinese and European painters. The Chinese palette includes heavy use of red lead and orpiment, pigments that were hardly sed in Europe anymore. More modern pigments like zinc white, cadmium yellow, viridian, chromates, cobalt blues or SOP were not found at all in the Chinese paintings.
The evolutionary success of insects is promoted by their association with beneficial microbes that enable the utilization of unusual diets. The synanthropic clothing moth Tineola bisselliella provides an intriguing example of this phenomenon. The caterpillars of this species have adapted to feed on keratin-rich diets such as feathers and wool, which cannot be digested by most other animals and are resistant to common digestive enzymes. Inspired by the hypothesis that this ability may be conferred by symbiotic microbes, we utilized a simple assay to detect keratinase activity and a method to screen gut bacteria for candidate enzymes, which were isolated from feather-fed larvae. The isolation of DNA from keratin-degrading bacterial strains followed by de novo genome sequencing resulted in the identification of a novel bacterial strain related to Bacillus sp. FDAARGOS_235. Genome Annotation identified 20 genes with keratinase domains. Proteomic analysis of the culture supernatant from this gut bacterium grown in non-nutrient buffer supplemented with feathers revealed several candidate enzymes potentially responsible for keratin degradation, including a thiol-disulfide oxidoreductase and multiple proteases. Our results suggest that the unusual diet of T. bisselliella larvae promotes their association with keratinolytic microorganisms and that the ability of larvae to feed on keratin can at least partially be attributed to bacteria that produce a cocktail of keratin-degrading enzymes.
Biofilm formation in industrial or medical settings is usually unwanted and leads to serious health problems and high costs. Inhibition of initial bacterial adhesion prevents biofilm formation and is, therefore, a major mechanism of antimicrobial action of surfaces. Surface topography largely influences the interaction between bacteria and surfaces which makes topography an ideal base for antifouling strategies and eco-friendly alternatives to chemical surface modifications. Femtosecond laser-processing was used to fabricate sub-micrometric surface structures on silicon and stainless steel for the development of antifouling topographies on technical materials.
What Does Ectoine Do to DNA? A Molecular-Scale Picture of Compatible Solute−Biopolymer Interactions
(2020)
Compatible solutes are accumulated in the cytoplasm of halophilic microorganisms. These molecules enable their survival in a high salinity environment. Ectoine is such a compatible solute. It is a zwitterionic molecule which strongly interacts with surrounding water molecules and changes the dynamics of the local hydration shell. Ectoine interacts with biomolecules such as lipids, proteins and DNA. The molecular interaction between ectoine and biomolecules in particular the interaction between ectoine and DNA is far from being understood.
In this paper we describe molecular aspects of the interaction between ectoine and double stranded DNA(dsDNA). Two 20 base pairs long dsDNA fragments were immobilized on a Gold surface via a thiol-tether. The interaction between the dsDNA monolayers with diluted and concentrated ectoine solutions was examined by means of X-ray photoelectron and polarization modulation infrared reflection absorption spectroscopies (PM IRRAS). Experimental results indicate that the ability of ectoine to bind water reduces the strength of hydrogen bonds formed to the ribose-phosphate backbone in the dsDNA. In diluted (0.1 M) ectoine solution, DNA interacts predominantly with water molecules. The sugar-phosphate backbone is involved in the formation of strong hydrogen bonds to water, which with elapsing time leads to a reorientation of the planes of nucleic acid bases. This reorientation destabilizes the hydrogen bonds strength between the bases and leads to a partial dehybridizaiton of the dsDNA. In concentrated ectoine solution (2.5 M), almost all water molecules interact with ectoine. Under this condition ectoine is able to interact directly with DNA. Density functional theory (DFT) calculations demonstrate that the direct interaction involves the nitrogen atoms in ectoine and phosphate groups in the DNA molecule. The results of the quantum chemical calculations Show that rearrangements in the ribose-phosphate backbone, caused by a direct interaction with ectoine, facilitates contacts between O atom in the phosphate group and H atoms in a nucleic acid base. In the PM IRRA spectra, an increase in the number of the IR absorption modes in the base pair frequency region proves that the hydrogen bonds between bases become weaker.
Thus, a sequence of reorientations caused by interaction with ectoine leads to a breakdown of hydrogen bonds between bases in the double helix.
Recent research has suggested that some of the inks used in Herculaneum papyri do not consist of pure carbon. Starting from this finding, in June 2018 a preliminary campaign of analysis by means of X-Ray fluorescence (XRF) of external portions removed mechanically from their original rolls in the eighteenth century (the so-called scorze) took place at the Biblioteca Nazionale at Naples. Also in this case, the aim of the survey was to investigate the ink composition in order to detect possible traces of metal. This article sums up the results of this survey.
Im Rahmen des Forschungsvorhabens wurde die biologische Prüfmethode der Checkliste zur stoffli-chen Bewertung im Rahmen des Aufnahmeverfahrens für weitere Topfkonservierungsmittel in den Anhang 1 zur Vergabegrundlage RAL-UZ102 „Emissionsarme Innenwandfarben“ überarbeitet. Der Test für den Einsatz von Konservierungsmitteln in seiner jetzigen Fassung besteht seit nahezu 20 Jah-ren und erfolgt ausschließlich an weißer Dispersionsfarbe für den Innenraum. Die hierbei ermittelten Höchstmengen für den Einsatz von Topfkonservierern werden z.Zt. auch auf andere Innenraumbau-produkte übertragen. Ziel war es zu klären, ob die Anforderungen an die Topfkonservierung bei Far-ben tatsächlich für andere Innenraumbauprodukte übernommen werden können. Die im Vorhaben durchgeführten Versuche deuten darauf hin, dass dies nicht ohne weiteres möglich ist. Nach Rückspra-che mit Vertretern aus der Industrie wurde das Keimspektrum für die Prüfung zudem um Hefe- und Schimmelpilze erweitert. Des Weiteren wurde eine künstliche Alterung eingeführt und überprüft, ob dies einen Einfluss auf den Gehalt an Isothiazolinonen hat. Die Konzentration von Isothialzolinonen wurde mittels Ultra-Hochleistungsflüssigkeitschromatographie kontrolliert und hinsichtlich einer Kor-relation mit dem Wachstum von Mikroorganismen ausgewertet. Da die in den Innenraumbauproduk-ten zugesetzten Isothiazolinone als Kontaktallergene bekannt sind, ist es ein Ziel des „Blauen Engel“-Umweltzeichens, die geringste erforderliche Menge an Konservierungsmittel in den Produkten zu ver-wenden, ohne die positive Auswirkung der Topfkonservierung zu gefährden. Daher sind die Optimie-rung der Leistungsstärke von Konservierungsmitteln und die Kontrolle der Hygiene im Herstellungs-prozess von zunehmender Bedeutung. Um Einblicke in den Herstellungsprozess von Farben zu gewin-nen, wurden im Rahmen des Vorhabens vier Farbwerke besichtigt, in denen weiße Innenraumfarben produziert werden, die mit dem Umweltzeichen „Blauer Engel“ ausgezeichnet sind. Gemeinsam mit den Fachleuten vor Ort wurde diskutiert, welche Maßnahmen zur Verbesserung der Werkshygiene er-griffen werden können, um den Einsatz von Topfkonservierern möglichst gering zu halten. Des Weite-ren wurde in dem Forschungsvorhaben untersucht, ob eine schnellere Bestimmung der Keimzahl in den Rohstoffen mittels quantitativer Polymerasekettenreaktion bereits im Farbwerk realisierbar ist.
The Brazilian sugarcane industry produced around 173 million tons (Mt) of bagasse in 2018. Bagasse is a by-product of juice extraction for ethanol and sugar production and is combusted in order to generate power, producing up to 10 Mt of ash per year. This ash contains various concentrations of plant nutrients, which allow the ash to be used as a crop fertilizer. However, the concentration and extractability of phosphorus (P), an essential plant nutrient, are low in bagasse ash. To increase the P content, we co-gasified and co-combusted bagasse with P-rich chicken manure. The resulting ash was thermochemically post-treated with alkali additives (Na2SO4 and K2SO4) to increase the availability of P to plants. We aimed to: (i) investigate the effect of thermochemical post-treatment of co-gasification residue and co-combustion ash on P availability to soybeans, (ii) explore the potential of chemical extraction methods (citric acid, neutral ammonium citrate, formic acid, and Mehlich-I) and diffusive gradients in thin films (DGT) to predict the availability of P to soybeans, and (iii) identify the responsible P-phases using X-ray diffraction . We evaluated P availability to soybeans growing in Brazilian Oxisol soil in two independent greenhouse pot experiments. The positive effect of thermochemical treatment on P availability from gasification residue was confirmed through the observation of increased P uptake and biomass in soybean plants. These findings were confirmed by chemical extraction methods and DGT. The gasification residue contained whitlockite as its main P-bearing phase. Thermochemical post-treatment converted whitlockite into highly soluble CaNaPO4. In contrast, co-combustion ash already contained highly soluble Ca(Na,K)PO4 as its main P-bearing phase, making thermochemical post-treatment unnecessary for increasing P availability. In conclusion, increased extractability and availability of P for soybeans were closely connected to the formation of calcium alkali phosphate. Our findings indicate that this combined methodology allows for the prediction of P-fertilization effects of ash.
Stress is a normal part of life for fungi, which can survive in environments considered inhospitable or hostile for other organisms. Due to the ability of fungi to respond to, survive in, and transform the environment, even under severe stresses, many researchers are exploring the mechanisms that enable fungi to adapt to stress. The International Symposium on Fungal Stress (ISFUS) brings together leading scientists from around the world who research fungal stress. This article discusses presentations given at the third ISFUS, held in Sao Jose dos Campos, Sao Paulo, Brazil in 2019, thereby summarizing the state-of-the-art knowledge on fungal stress, a field that includes microbiology, agriculture, ecology, biotechnology, medicine, and astrobiology.
Timber is constantly exposed to environmental influences under outdoor conditions which limits its Lifetime and usability. In order to counteract the damaging processes caused by insects, we have developed a novel and more environmentally friendly method to protect wood materials via covalent modification by organic insecticides. Starting with an important class of synthetic insecticides which are derived from the natural insecticide nicotine, various new carboxylic acid derivatives of imidacloprid were made accessible. These activated neonicotinoids were utilized for the chemical modification of wood hydroxy groups. In contrast to conventional wood preservation methods in which biocides are only physically bound to the surface for a limited time, the covalent fixation of the preservative guarantees a permanent effect against wood pests, demonstrated in standardized biological tests. Additionally, the environmental interaction caused by non-bound neonicotinoids is significantly reduced, since both, a smaller application rate is required and leaching of the active ingredient is prevented. By minimizing the pest infestation, the lifetime of the material increases while preserving the natural appearance of the material.
The Montserrat Codex Miscellaneus (TM 59453/LDAB 552) has been the subject of numerous studies since the publication of ist first text by its owner, father Ramon Roca-Puig. Scholars have dealt with the content of its texts, as well as interrogated its origin and materiality. It is a fourth-century papyrus single quire codex, which contains texts in both Latin and Greek. It has been argued that it belonged to the Bodmer library, connected to a Pachomian library in the Thebaid. In this paper we want to contribute to the material study of the codex by presenting the first results of an archaeometric analysis performed upon the inks. The Analysis was carried out within the framework of the ‘PAThs’ project based at Sapienza University of Rome, and executed with the close cooperation of DVCTVS, a team of scholars who curate the Roca-Puig collection. The results obtained have not only cast light on the history of production of the codex, but also, and perhaps most importantly, point out that a meaningful interpretation of the analytical data is only possible through an interdisciplinary collaboration between the humanities and the natural sciences.
Weltweit werden etwa 80–85 % aller abgebauten Rohphosphate für die Produktion von Düngemitteln verwendet. Bei noch steigendem Bedarf an Phosphor (P) geht man derzeit davon aus, dass die weltweiten P-Reserven noch über 200 Jahre ausreichen. Um den P-Vorrat langfristig abzusichern, sollte der in Reststoffen enthaltene Phosphor möglichst umfänglich genutzt werden. Dieser Forderung trägt das von der Bundesregierung 2012 erstmals beschlossene Deutsche Ressourceneffizienzprogramm ProgRess Rechnung. Rohphosphat wird auch seitens der Europäischen Kommission aufgrundseiner ökonomischen Bedeutung und des unsicheren Angebots als „kritischer Rohstoff“ eingestuft. Vor diesem Hintergrund hat die Bundesregierung in der Verordnung zur Neuordnung der Klärschlammverwertung vom 27. September 2017 in Deutschland eine verpflichtende technische Rückgewinnung von Phosphor für Abwasserbehandlungsanlagen ab einer Ausbaugröße von 100.000 Einwohnerwerten (12 Jahre nach Inkrafttreten der Verordnung) bzw. ab einer Ausbaugröße von über 50.000 Einwohnerwerten (15 Jahre nach Inkrafttreten der Verordnung) vorgeschrieben. Die Verordnung enthält keine Vorgaben hinsichtlich der anzuwendenden Technologie bei der Phosphorrückgewinnung. Ausgenommen von der Rückgewinnungspflicht sind Klärschlämme mit niedrigen Phosphorgehalten (weniger als 20 Gramm Phosphor je Kilogramm Klärschlamm-Trockenmasse). Auch die im Jahre 2017 verabschiedeten neuen Rechtsvorschriften für die Düngung verlangen zukünftig einen nachhaltigen und ressourceneffizienten Umgang mit Nährstoffen bei der landwirtschaftlichen Erzeugung und schränken die P-Zufuhr insbesondere auf hoch versorgten Böden ein (Düngeverordnung vom 26. Mai 2017). Dies wird zu einem mehr am Pflanzenbedarf orientierten und ggf. vermehrt überbetrieblichen Einsatz von wirtschaftseigenen Düngern führen. Um den politischen und gesetzlichen Anforderungen gerecht zu werden, müssen einerseits wirksame und kosteneffiziente technische Verfahren zum P-Recycling (weiter)entwickelt werden. Andererseits müssen die Recyclingprodukte die Anforderungen für eine direkte Verwendung in der Landwirtschaft oder als Rohstoff für die Herstellung von Düngemitteln erfüllen. In dem vorliegenden Standpunkt wird zunächst der potenzielle Beitrag von Reststoffen zur Deckung des P-Bedarfs in der deutschen Pflanzenproduktion geschätzt. Für die wichtigsten Reststoffe werden technische Verfahren zur P-Rückgewinnung bzw. Aufarbeitung skizziert. Auf Basis der Anforderungen der Landwirtschaft bzw. der Düngemittelindustrie
an die P-Recyclingprodukte werden deren Herstellungsverfahren bewertet. Schließlich wird der Regelungs- und Forschungsbedarf formuliert.
New antibacterial agents are urgently required to fight the emergence of antibiotic-resistant bacteria. We recently synthesized the first thioimidazolium ionene, which has antibacterial properties and can degrade in various media. This dual functionality is crucial in order to limit the environmental impact of these biocides. We have found that our polymer is stronger than benzalkonium chloride (BAC) against Pseudomonas aeruginosa and also readily degrades in the presence of base, while remaining stable in acidic environments. These results highlight a new emerging class of antibacterial degradable polymers.
The application of fracture mechanics to the determination of the fatigue behavior of weldments is discussed with the focus on classic fatigue, i.e., the overall fatigue life and the fatigue strength in terms of an S-N curve and the endurance limit. The following issues are addressed: specific features of short fatigue crack propagation, an adequate initial crack size, multiple crack propagation and its statistical treatment as well as welding residual stresses. As an example, an approach of the authors is applied to the determination of FAT classes for a butt weld with varying weld toe geometry.
In the present study, a simple approach was used to investigate the effect of UV-exposure on two high density Polyethylene materials (PE-HD), commonly used for storage tanks, on fuel sorption behavior and colonization by microorganisms. The aim was to investigate whether the sorption behavior of the fuels (diesel/biodiesel) and the colonization by microorganisms, frequently occurring in the fuel, is affected and may lead to undesirable or safety-relevant material changes. We showed that the UV-irradiation leads to significant changes of the sorption behavior due to chemi-crystallization and crosslinking. The fuel Sorption is affected by the UV-induced formation of polar carbonyl and hydroxyl groups predominantly occurring at the surface. With respect to microbial colonization behavior for Bacillus subtilis and Pseudomonas aeruginosa, isolated from a contaminated diesel sample, differences of the initial adhesion could be shown depending on the initial type of polyethylene as well as on the degree of UV-induced degradation.
An interdisciplinary approach to the study of manuscript traditions is here applied to the analysis of the leaves from the White Monastery, one of the greatest centres of literary production in Late Antique Egypt. In the framework of the ‘PAThs’ project, archaeometric analyses complement the information pieced together by a range of disciplines in the field of humanities. The use of different complementary analytical techniques provides information on the type of ink used and its elemental composition, unveiling interesting details regarding the materials and methodology of manufacturing of writing media. Moreover, this contribution takes a step forward and discusses the possible existence of a regional arrangement in the elemental composition revealed in the inks studied.
Phosphorus (P) fertilizers from secondary resources became increasingly important in the last years. However, these novel P-fertilizers can also contain toxic pollutants such as chromium in its hexavalent state (Cr(VI)). This hazardous form of chromium is therefore regulated with low limit values for agricultural products even though the correct determination of Cr(VI) in these fertilizers may be hampered by redox processes, leading to false results. Thus, we applied the novel diffusive gradients in thin-films (DGT) technique for 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 for most tested materials 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) so that Cr(VI) values are overestimated. Since certain types of the P fertilizers contain mobile Cr(III) or partly immobile Cr(VI), it is necessary to optimize the DGT binding layers to avoid aforementioned over- or underestimation. Furthermore, our investigations showed that the Cr K-edge XANES spectroscopy technique is unsuitable to determine small amounts of Cr(VI) in fertilizers (below approx. 1% of Cr(VI) in relation to total Cr).
Fungi that share light-flooded habitats with phototrophs may profit from their excess photosynthetic products. But to cope with sunlight-associated stresses [e.g. high temperatures, UV radiation with associated DNA damage, accumulation of reactive oxygen species (ROS), desiccation and osmotic 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 [dihydroxynaphthalene (DHN) melanin-containing] fungi from phyllosphere and exposed solid surfaces contain multiple photoreceptors (PRs). The 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 Dothideomycetes and Eurotiomycetes including Knufia petricola possess equal numbers ofPRs along with the same set of protective pigments. This similarity between black fungi from plant and rock surfaces suggests that photoperception and -regulation are important for fungi that receive nutrients through cooperation with phototrophs. Genetic tools for manipulating K. petricola exist and will be used to test this idea.
Das Element Phosphor ist für alle Lebewesen essenziell und wird beispielsweise von Pflanzen in Form von Phosphaten aufgenommen.
In der landwirtschaftlichen Produktion werden dem Boden die Phosphate durch Wachstum und Ernte der Pflanzen entzogen und müssen ihm in Form von Phosphatdüngemitteln wieder zugeführt werden, um die Nahrungsmittelproduktion zu sichern. Rohphosphat stellt die Grundlage unserer derzeitigen Phosphatdüngemittel dar, ist aber gleichzeitig ein endlicher Rohstoff.
Des Weiteren sind insbesondere sedimentäre Rohphosphate oftmals mit erheblichen Konzentrationen toxischer Schadstoffe wie Cadmium, Uran und Thorium belastet. Eine Kreislaufführung des Phosphats sollte erfolgen, um natürliche Rohstoffvorkommen zu schonen und den Eintrag von Schadstoffen auf unsere Böden zu unterbinden.
Many organizations in Europe collect data and perform research on municipal solid waste and the secondary raw materials that can be produced from them through recycling, urban mining, or landfill mining.However, the information generated and presented thereby is often highly aggregated, while research activities are many a time isolated. Both reduce the usability of the data and information generated. In order to better structure the knowledge generation on secondary raw materials production from municipal solid waste, we suggest to learn from the traditional raw materials mining Industry how to perform an integrated assessment and reporting of anthropogenic resources. This is exemplarily shown for the case of the anthropogenic resource municipal solid waste incineration bottom ash and airpollution control residues. A network of expert institutions from countries throughout Europe was build up to compile the information on legal and technological aspects for the recovery of different secondary raw materials from these residues, including construction minerals, metals, and salts. We highlight in our article the strength of the combined knowledge of an expert network not only on legal and technological, but also local and site-specific aspects of the recovery of secondary raw materials. By doing so, we hope to kick-off a discussion for how to organize and implement a structure for a better management of knowledge on anthropogenic resources, in order to provide a sustainable supply of secondary raw materials for a greener and more circular economy.
EI‐GEO is a multinational research project (Germany, Latvia, Russia) funded under the ERA.Net RUS Plus Call 2017. Aim of the project is the investigation whether geosynthetics in hydraulic engineering applications could be a source of microplastics (MPs) and other contaminants to the aquatic environment causing negative effects to aquatic organisms.
Whereas the behavior of geosynthetics in landfill engineering is well studied and documented since decades, little is known on application in applications such as coastal protection or ballast layers for wind energy plants. However, due to the rapid expansion of offshore wind energy, rising water levels and more extreme weather conditions as a result of climate change more and more hydraulic engineering projects will be realized in the future.
Applied methods are artificial ageing of geosynthetics in environmental simulation chambers, storage of samples under environmental condition for comparison with laboratory simulation, sample characterization by microscopic methods and ecotoxicological testing of water in contact with geosynthetics.
In parallel a case study at the Baltic Sea shore at Kaliningrad Oblast (Russia) will be performed. The aim of study is to estimate the level of pollution of the beaches by geosynthetic debris and identify the possible sources.
Biofilms cause complications and high costs in both industry and medicine. Of particular interest are bacterial infections of prosthetic materials, which usually cannot be eliminated due to the high antibiotic resistance known for bacteria forming biofilms. The search for new materials and coatings with lower colonization potential and antibacterial activity is of great importance to reduce biofilm formation. However, there is no standardized procedure to examine the colonization characteristics of bacteria in the Biofilm state in situ. Here, we describe an automated epifluorescence microscopy system for the semi-quantitative analysis of three-dimensional (3D) biofilms on various surfaces. To analyze adherent bacteria, three materials (glass, steel and titanium) were incubated with bacteria in a flow chamber system. After fluorescence staining of the bacteria, automated image capturing, quantification of the bacteria, measurement of the colonized area and determination of the 3D biofilm height were carried out by using novel software.
Furthermore, the materials were examined for their surface topography using white light scanning interferometry. Titanium compared to glass showed a significantly higher number of adherent bacteria.
We argue that this was due to the higher microroughness of titanium. The colonized area was in accordance with the number of adherent bacteria and was also significantly larger on titanium coupons compared to glass. Maximum 3D biofilm height on glass coupons was significantly lower compared to the ones on steel and titanium. This novel method enables the standardized, automated investigation of the colonization with bacteria on different materials. This approach can considerably support the characterization of new material surfaces and their innovative coatings by analyzing the amount of attached Bacteria and thickness of biofilms in situ and eliminates the need of conventional cultivation.
Fluorides are well-known as wood preservatives. One of the limitations of fluoride-based wood preservatives is their high leachability. Alternative to current fluoride salts such as NaF used in wood protection are low water-soluble fluorides. However, impregnation of low water-soluble fluorides into wood poses a challenge. To address this challenge, low water-soluble fluorides like calcium fluoride (CaF2) and magnesium fluoride (MgF2) were synthesized as nanoparticles via the fluorolytic sol−gel synthesis and then impregnated into wood specimens. In this study, the toxicity of nano metal fluorides was assessed by termite mortality, mass loss and visual analysis of treated specimens after eight weeks of exposure to termites, Coptotermes formosanus. Nano metal fluorides with sol concentrations of 0.5 M and higher were found to be effective against termites resulting in 100% termite mortality and significantly inhibited termite feeding. Among the formulations tested, the least damage was found for specimens treated with combinations of CaF2 and MgF2 with an average mass loss less than 1% and visual rating of “1”. These results demonstrate the efficacy of low water-soluble nano metal fluorides to protect Wood from termite attack.
Potential use of incineration bottom ash in construction – Evaluation of the environmental impact
(2020)
Knowledge of the long-term leaching behavior of potentially harmful substances is crucial for the assessment of the environmental compatibility of reusing municipal solid-waste incineration bottom ash (MSWI BA) in construction, i.e., as a road base layer.
BA fractions obtained from wet-processing aiming at the improvement of environmental quality were used to investigate the mobility of relevant substances. Eluates from laboratory-scaled leaching procedures (column percolation and lysimeters) were analyzed to learn about the long-term release of substances. Unsaturated conditions and artificial rainwater (AR) were used in the lysimeter tests to simulate field conditions. In addition, batch test eluates were generated at usual liquid-to-solid ratios (L/S) for compliance testing purposes. A variety of cations and anions was measured in the eluates.
The wet treatment reduces the leaching of chloride and particularly sulfate by more than 60%. The release of typical contaminants for the treated MSWI BA such as the heavy metals Cu and Cr was well below 1% in the conducted leaching tests.
An increase in the Sb concentration observed in the lysimeter experiments starting at L/S 0.75 L/kg and in the column experiment at L/S 4 L/kg is assumed to be related to decreasing concentrations of Ca and thus to the dissolution of sparingly soluble calcium antimonate. The same leaching mechanism applies with V, but the concentration levels observed are less critical regarding relevant limit values. However, on the long term the behavior of Sb could be problematic for the application of MSWI BA in construction.