Showing papers by "University of Münster published in 2023"

Light-Responsive Conductive Surface Coatings on the Basis of Azidomethyl-PEDOT Electropolymer Films

Abstract: The design of responsive coatings has gained increasing attention recently, with light-responsive interfaces receiving particular appreciation, as their surface properties can be modulated with excellent spatiotemporal control. In this article, we present light-responsive conductive coatings acquired through a copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction between electropolymerized azide-functionalized poly(3,4-ethylenedioxythiophene) (PEDOT-N3) and arylazopyrazole (AAP)-bearing alkynes. The UV/vis and X-ray photoelectron spectroscopy (XPS) data indicate a successful post-modification, supporting a covalent attachment of AAP moieties to PEDOT-N3. The thickness and degree of PEDOT-N3 modification are accessible by varying the amount of passed charge during electropolymerization and time of reaction, respectively, providing a degree of synthetic control over the physicochemical material properties. The produced substrates demonstrate a reversible and stable light-driven switching of photochromic properties in both "dry" and swelled states, as well as efficient electrocatalytic Z → E switching. The AAP-modified polymer substrates exhibit a light-controlled wetting behavior, demonstrating a consistently reversible switching of the static water contact angle with a difference up to 10.0° for CF3-AAP@PEDOT-N3. The results highlight the application of conducting PEDOT-N3 for the covalent immobilization of molecular switches while preserving their stimuli-responsive features.

Stereochemical Editing

Abstract: Stereochemical editing has recently risen to prominence, allowing the direct editing of organic molecules with stereocenter(s) to adjust their relative stereochemistry at a late-stage. Several seminal light-driven stereochemical editing reactions such as deracemization and epimerization have been successively developed. Recently, Wendlandt and co-workers reported a versatile photochemical epimerization of unactivated tertiary stereogenic centers to rapidly prepare the stereoisomers that were previously challenging to access.

Vascular risk factors, white matter microstructure, and depressive symptoms: a longitudinal analysis in the UK Biobank

Abstract: Abstract Background Cumulative burden from vascular risk factors (VRFs) has been associated with an increased risk of depressive symptoms in mid- and later life. It has been hypothesised that this association arises because VRFs disconnect fronto-subcortical white matter tracts involved in mood regulation, which puts older adults at higher risk of developing depressive symptoms. However, evidence for the hypothesis that disconnection of white matter tracts underlies the association between VRF burden and depressive symptoms from longitudinal studies is scarce. Methods This preregistered study analysed longitudinal data from 6,964 middle-aged and older adults from the UK Biobank who participated in consecutive assessments of VRFs, brain imaging, and depressive symptoms. Using mediation modelling, we directly tested to what extend white matter microstructure mediates the longitudinal association between VRF burden and depressive symptoms. Results VRF burden showed a small association with depressive symptoms at follow-up. However, there was no evidence that fractional anisotropy (FA) of white matter tracts mediated this association. Additional analyses also yielded no mediating effects using alternative operationalisations of VRF burden, mean diffusivity (MD) of single tracts, or overall average of tract-based white matter microstructure (global FA, global MD, white matter hyperintensity volume). Conclusions Our results lend no support to the hypothesis that disconnection of white matter tracts underlies the association between VRF burden and depressive symptoms, while highlighting the relevance of using longitudinal data to directly test pathways linking vascular and mental health.

neuroWalknet, a controller for hexapod walking allowing for context dependent behavior

Abstract: Decentralized control has been established as a key control principle in insect walking and has been successfully leveraged to account for a wide range of walking behaviors in the proposed neuroWalknet architecture. This controller allows for walking patterns at different velocities in both, forward and backward direction—quite similar to the behavior shown in stick insects—, for negotiation of curves, and for robustly dealing with various disturbances. While these simulations focus on the cooperation of different, decentrally controlled legs, here we consider a set of biological experiments not yet been tested by neuroWalknet, that focus on the function of the individual leg and are context dependent. These intraleg studies deal with four groups of interjoint reflexes. The reflexes are elicited by stimulation of the femoral chordotonal organ (fCO) or groups of campaniform sensilla (CS). Motor output signals are recorded from the alpha-joint, the beta-joint or the gamma-joint of the leg. Furthermore, the influence of these sensory inputs to artificially induced oscillations by application of pilocarpine has been studied. Although these biological data represent results obtained from different local reflexes in different contexts, they fit with and are embedded into the behavior shown by the global structure of neuroWalknet. In particular, a specific and intensively studied behavior, active reaction, has since long been assumed to represent a separate behavioral element, from which it is not clear why it occurs in some situations, but not in others. This question could now be explained as an emergent property of the holistic structure of neuroWalknet which has shown to be able to produce artificially elicited pilocarpine-driven oscillation that can be controlled by sensory input without the need of explicit innate CPG structures. As the simulation data result from a holistic system, further results were obtained that could be used as predictions to be tested in further biological experiments.

Guided growth: angular deformity correction through temporary hemiepiphysiodesis with a novel flexible staple (FlexTack)

Abstract: Aims Temporary hemiepiphysiodesis (HED) is applied to children and adolescents to correct angular deformities (ADs) in long bones through guided growth. Traditional Blount staples or two-hole plates are mainly used for this indication. Despite precise surgical techniques and attentive postoperative follow-up, implant-associated complications are frequently described. To address these pitfalls, a flexible staple was developed to combine the advantages of the established implants. This study provides the first results of guided growth using the new implant and compares these with the established two-hole plates and Blount staples. Methods Between January 2013 and December 2016, 138 patients (22 children, 116 adolescents) with genu valgum or genu varum were treated with 285 flexible staples. The minimum follow-up was 24 months. These results were compared with 98 patients treated with 205 two-hole plates and 92 patients treated with 535 Blount staples. In long-standing anteroposterior radiographs, mechanical axis deviations (MADs) were measured before and during treatment to analyze treatment efficiency. The evaluation of the new flexible staple was performed according to the idea, development, evaluation, assessment, long-term (IDEAL) study framework (Stage 2a). Results Overall, 79% (109/138) of patients treated with flexible staples achieved sufficient deformity correction. The median treatment duration was 16 months (interquartile range (IQR) 8 to 21). The flexible staples achieved a median MAD correction of 1.2 mm/month/HED site (IQR 0.6 to 2.0) in valgus deformities and 0.6 mm/month/HED site (IQR 0.2 to 1.5) in varus deformities. Wound infections occurred in 1%, haematomas and joint effusions in 4%, and implant-associated complications in 1% of patients treated with flexible staples. Valgus AD were corrected faster using flexible staples than two-hole plates and Blount staples. Furthermore, the median MAD after treatment was lower in varus and valgus AD, fewer implant-associated complications were detected, and reduced implantation times were recorded using flexible staples. Conclusion The flexible staple seems to be a viable option for guided growth, showing comparable or possibly better results regarding correction speed and reducing implant-associated complications. Further comparative studies are required to substantiate these findings. Cite this article: Bone Joint J 2023;105-B(3):331–340.

Behavioural Change in Local Authorities to Increase Organisational Capacity

Abstract: Local authorities’ transport departments face extraordinary requirements regarding future mobility planning that affects and disrupts their internal business models and institutional logic in substantive ways. In this chapter, we highlight how organisational change can be implemented in local authorities to allow organisational capacity to increase and to enable employees to cope with the increasing expectations and requirements of future mobility planning. Our bottom-up approach is based on a socio-technical approach, taking into account both social (e.g., changing social behaviours or values) and technical aspects (e.g., new technologies). Applying Kotter’s Eight Stage Process, we outline the implementation process of organisational change followed in seven local authorities in Europe as part of the SUITS project. The multiple case study approach allows us to indicate the crucial points along the path towards organisational change and to provide a step-by-step guide for successful implementation of organisational change in local authorities. We provide best practice examples from our work that may help other European cities increase their organisational capacity and be prepared to cope with the extraordinary requirements in relation to future mobility planning.

Formation of Thermochemical Heterogeneities by Core‐Mantle Interaction

Abstract: Earth's core-mantle boundary (CMB) shows a complex structure with various seismic anomalies such as the large low shear-wave velocity provinces (LLSVPs) and ultra-low velocity zones (ULVZs). As these structures are possibly induced by chemically distinct material forming a layer above the CMB, models of mantle convection made ad hoc assumptions to simulate the dynamics of this layer. In particular, density and mass were prescribed. Both conditions are critical for the dynamics but hardly constrained. Core-mantle interaction is considered as one possible origin for this dense layer. For example, diffusion-controlled enrichment of iron has been proposed. We here apply a chemical gradient between the mantle and the denser core to analyze the penetration of dense material into the mantle. As such, we employ 2D Cartesian models where a thermochemical layer at the base of the mantle develops self-consistently by a diffusive chemical influx. Our simulations indicate that chemical diffusion is strongly affected by the convective mantle flow. This convection-assisted diffusion yields a compositional influx mainly in the areas where slabs spread over the bottom boundary and sweep dense material aside to form accumulations with rising plumes atop. Like for a prescribed dense layer this process leads to chemically distinct piles, which are typically smaller (therefore more suited to explain ULVZs) but more persistent due to the constant chemical influx. Combining the influx scenario with the primordial layer can possibly explain the simultaneous existence of LLSVPs and ULVZs along with the observation of a core-like isotopic composition in the mantle.

Towards a network control theory of electroconvulsive therapy response

Abstract: Electroconvulsive Therapy (ECT) is arguably the most effective intervention for treatment-resistant depression. While large interindividual variability exists, a theory capable of explaining individual response to ECT remains elusive. To address this, we posit a quantitative, mechanistic framework of ECT response based on Network Control Theory (NCT). Then, we empirically test our approach and employ it to predict ECT treatment response. To this end, we derive a formal association between Postictal Suppression Index (PSI)-an ECT seizure quality index-and whole-brain modal and average controllability, NCT metrics based on white-matter brain network architecture, respectively. Exploiting the known association of ECT response and PSI, we then hypothesized an association between our controllability metrics and ECT response mediated by PSI. We formally tested this conjecture in N = 50 depressive patients undergoing ECT. We show that whole-brain controllability metrics based on pre-ECT structural connectome data predict ECT response in accordance with our hypotheses. In addition, we show the expected mediation effects via PSI. Importantly, our theoretically motivated metrics are at least on par with extensive machine learning models based on pre-ECT connectome data. In summary, we derived and tested a control-theoretic framework capable of predicting ECT response based on individual brain network architecture. It makes testable, quantitative predictions regarding individual therapeutic response, which are corroborated by strong empirical evidence. Our work might constitute a starting point for a comprehensive, quantitative theory of personalized ECT interventions rooted in control theory.

Fine‐tuning Substrate‐‐Catalyst Halogen‐‐Halogen Interactions for Boosting Enantioselectivity in Halogen‐Bonding Catalysis

Abstract: A new approach towards highly enantioselective halogen-bonding catalysis has been developed. In order to circumvent the intrinsic issues of the halogen-bond (XB) nature and consequent unresolved limitations in asymmetric catalysis, fine-tuned halogen--halogen interactions between the substrate and XB-donor were designed to pre-organize the substrate in the catalyst’s cavity and boost enantiocontrol. The present strategy exploits both the electron cloud (Lewis base site) and the sigma (σ)-hole site of the halogen-substituent of the substrates to form a tight catalyst--substrate--counteranion chiral complex. Thus, this enables a controlled induction of high levels of chirality transfer. Remarkable enantioselectivities of up to 95:5 e.r. (90% ee) have been achieved in a model dearomatization reaction of halogen-substituted (iso)quinolines with tetrakis-iodotriazole multidentate anion-binding catalysts.

Inside Sales: Verankerungsmöglichkeiten in der Vertriebsorganisation und Konsequenzen für Vertriebsmitarbeiter

Abstract: Infolge der zunehmenden Nutzung digitaler Technologien und der daraus resultierenden digitalen Transformation im Vertrieb hat sich Inside Sales für viele Unternehmen als ein vielversprechendes Vertriebskonzept herausgestellt. Im Rahmen des Inside Sales nutzen Vertriebsmitarbeiter Telekommunikationstechnologien für den gesamten Verkaufsprozess. Die Autoren dieses Beitrags erläutern das Konzept des Inside Sales und grenzen es von anderen Vertriebskonzepten, wie Remote Sales und Telemarketing, ab. Sie stellen zudem dar, wie Inside Sales in der Vertriebsorganisation umgesetzt und das Zusammenspiel zwischen Inside Sales und Außendienst gestaltet werden kann. Die Autoren widmen sich außerdem der Frage, welche positiven und negativen Auswirkungen die verstärkte Nutzung digitaler Technologien im Inside Sales für individuelle Vertriebsmitarbeiter mit sich bringt. Daraus ergeben sich zentrale Handlungsempfehlungen für Vertriebsmanager, die es bei der Umsetzung von Inside Sales zu berücksichtigen gilt.

Changes of greenhouse gas fluxes and corresponding microbial communities upon rewetting of a coastal peatland with brackish seawater

Abstract: Rewetting of drained peatlands reduces the emissions of carbon dioxide (CO2) and nitrous oxide (N2O) substantially. However, elevated methane (CH4) emissions can occur, at least in the short-term. The impact of rewetting coastal peatlands with brackish water remains yet unclear, although beneficial effects such as lower CH4 emissions seem likely, due to high sulfate availability. Here, we compare pre- and post-rewetting greenhouse gas fluxes, biogeochemical parameters and the abundance of specific microbial groups in a coastal peatland at the German Baltic Sea coast that was formerly drained and used as an agricultural grassland and recently rewetted with brackish water. We hypothesized that flooding with brackish seawater reduces CO2 emissions despite favoring sulfate-reducers. It should also limit CH4 production and favor anaerobic methane and thus keep CH4 emissions low although aerobic methane oxidation may decrease. We measured CH4 and CO2 fluxes along a soil wetness gradient before rewetting and along a water level gradient after rewetting with brackish seawater and estimated cumulative CH4, CO2 net ecosystem exchange (NEE), and ecosystem respiration (Reco). Soil cores for biogeochemical and microbial analyses were taken at seven locations along the transect pre- and post-rewetting. We used quantitative polymerase chain reaction (qPCR) on 16S rRNA, mcrA, pmoA and dsrB genes to quantify the abundances of total prokaryotes, methanogens, aerobic methanotrophs and sulfate-reducing bacteria.After rewetting, cumulative CH4 net fluxes and NEE increased at locations that were previously dry, while Reco halved compared to before rewetting. This correlated with the absolute abundances of specific microbial groups and the surface/pore water biogeochemistry. Under the newly created water-logged conditions, the abundances of methanogenic as well as of sulfate-reducing bacteria (SRB) increased at previously dry sampling locations, but remained constant at the former ditch location. At the same time, the abundance of the aerobic methanotroph community on previously dry locations decreased, which indicates lower aerobic methane oxidation potentials. Pore water CH4 and CO2 concentrations suggest that gas production most likely increased at the former terrestrial locations and stable carbon isotope measurements support an increase of methanogenesis in the peat at some locations. Isotopic analyses also provide some support for persistent methane oxidation either through anaerobic or aerobic taxa at one location.Brackish water rewetting strongly modified the dominant methane-cycling processes but resulted in higher greenhouse gas emissions of both CO2 and CH4 in the first year after rewetting. As expected, CH4 emissions after rewetting were lower than in freshwater rewetted fens, while NEE was unexpectedly high. Since Reco strongly decreased, we assume that peat mineralization was successfully prevented and that ongoing CO2 emissions rather derived from strongly reduced CO2 uptake, supply of terminal electron acceptors (especially sulfate), and excess substrate availability from decaying vegetation. There is great potential for reduction of both, CH4 and CO2 emissions after the initial boost when readily available substrate is depleted. However, our study also reveals the complexity of peatland restoration and the possibility of transient effects upon rewetting, and therefore the value of undrained, pristine peatlands as well as their importance in sequestering carbon.

Facilitating [2+2] Photocycloadditions by Promoting Oxygen Tolerance and Substrate Activation in Water

Abstract: Micellar photocatalysis allows for a simple and benign reaction set-up using water as the solvent without the need for oxygen-removing protocols. Blue light (456 nm) is absorbed by the photocatalyst and allows the [2+2] photocycloaddition to occur between α,β-unsaturated carbonyl compounds and activated alkenes. The observed reactivity for α,β-unsaturated aldehydes is completely turned on by the use of a micellar solution as opposed to organic solvents. More information can be found in the Research Article by L. Næsborg and co-workers (DOI: 10.1002/chem.202300627).

Magnetotelluric data across Ciomadul volcano and the Perşani Volcanic Field — constrains on the nature and structure of the magma storage system

Abstract: Ciomadul volcano, located at the south-eastern terminus of the Carpathian volcanic arc (Romania), is the youngest volcano in eastern-central Europe, with the last eruption occurring at 32 ka. Petrological and geophysical constraints indicate a melt-bearing silicic crystal mush body beneath Ciomadul, approximately 5–20 km below surface. This suggests that long-dormant or seemingly inactive volcanoes may have potentially active magma storage systems. However, the geometry and size of the magma storage region is unknown. Understanding the nature and structure of the volcanic plumbing system is crucial to understanding the evolution of the system, as well as to assess the hazard potential.In this presentation, we will report on 41 new magnetotelluric measurements acquired in 2022. The survey design consists of an irregular grid with dimensions of approximately 75 km by 75 km, centered around Ciomadul in the corner of the south-eastern Carpathian Mountains. This makes an array suitable for three-dimensional modelling. A 100 km long NW-SE transect across the array has a measurement spacing of less than 15 km.The newly acquired data complement previous measurements (recorded in 2010) near Ciomadul and Băile Tuşnad within an area of approximately 5 km by 10 km. The new data extend westward to the Perşani volcanic field (Racoș, Homorod), about 40 km west of Ciomadul, towards the Transylvanian Basin, and to the south-east to the edge of the seismically active Vrancea zone, often attributed to the descent of a slab, more than 50 km south-east of Ciomadul, towards the Focșani Basin. Both regions are targets for future measurement campaigns.Recordings were carried out at each location for approximately 1–5 days. The data typically had reliable periods of up to 1,000–4,000 s. The data are not homogenous and have characteristics of three-dimensionality. At some locations, cultural electromagnetic noise contaminated the signals and degraded the data; thus choosing appropriate locations for measurement was critical. Estimating local and inter-station transfer functions required special care, such as applying data pre-selection schemes and manual time windows, in addition to standard approaches including using robust statistics and the remote reference method. Overall, the preliminary analysis is encouraging and the results show that it is possible to obtain usable magnetotelluric data in this region.

Trends in surface moisture conditions of European peatlands in the last decades - a remote sensing approach

Abstract: Representing the Earth’s most efficient terrestrial carbon store, intact peatlands play a key role in climate change mitigation strategies and provide multiple other ecosystem services such as flood prevention and refugia for rare species. The carbon sink function of peatlands is yet highly dependent on water saturation and vegetation composition. Nevertheless, drainage and peat extraction during the past centuries until today led to intense peatland degradation and turned more than half of all European peat soils and more than 90 percent of peat soils in Germany into a carbon source. Efforts have been increasingly made since the 1990s to restore peatlands, mainly by rewetting to recover peatland typical hydrological conditions. However, there is a lack of knowledge on restoration success for numerous sites, due to difficulties in funding long-term hydrological monitoring. Satellite remote sensing is an excellent method to address this deficiency, as it provides spatially continuous and temporally highly resolved information on the environment, including peatlands.Making use of freely available data of the Landsat Mission, this study aims to analyze trends in surface moisture conditions of European peatlands over the last decades, a time frame in which many restoration measures have been implemented. We performed a pixel-wise trend analysis for European peatlands using the Normalized Difference Moisture Index as moisture indicator based on image time-series reaching back to 1984 and a spatial resolution of 30 x 30 m. Trend statistics using Mann-Kendall’s tau and Sen’s slope were calculated for each month separately to also enable analysis of changes in specific seasons, such as the growing season or shoulder seasons important for water recharge of the sites. Based on a random sample of peatland sites across all Europe, we show first results of european-wide trend patterns. For small-scale visualization and to facilitate a spatially explicit long-term monitoring of peatlands in active restoration management, we further present an open-source Google-Earth-Engine (GEE) application which additionally provides insights into changes in vegetation, as represented by the Normalized Difference Vegetation Index. Besides allowing the interpretation of changes in surface moisture conditions over the past decades, the GEE tool can also be used in the future to assess potential restoration sites or to improve our understanding concerning the resilience of peatlands in scenarios of a warming climate, where research is still in its infancy. The continental coverage of the analysis in combination with a temporal coverage of several decades on a monthly resolution offers exceptional possibilities for spatial planning and evaluation of European peatland restoration and can therefore contribute to a cost-effective implementation of climate change mitigation measures.

Methodisches Vorgehen

Abstract: Zusammenfassung In diesem Kapitel werden unter Rekurs auf die Forschungsfragen und das Forschungsinteresse die Datenerhebung und -analyse vorgestellt, begründet und reflektiert. Ausgehend von der hier eingenommenen analytischen Governanceperspektive und der angestrebten mehrperspektivischen Untersuchung werden methodische Zugriffsweisen eruiert, um sodann die Entscheidung für ein qualitatives Vorgehen mittels Interviews zu begründen. Anschließend wird herausgearbeitet, welchen Beitrag die leitfadengestützten Experteninterviews zur Beantwortung der Forschungsfragen leisten.

Heterogeneous integration of superconducting thin films and epitaxial semiconductor heterostructures with Lithium Niobate

Abstract: Abstract We report on scalable heterointegration of superconducting electrodes and epitaxial semiconductor quantum dots (QDs) on strong piezoelectric and optically nonlinear lithium niobate. The implemented processes combine the sputter-deposited thin film superconductor niobium nitride and III–V compound semiconductor membranes onto the host substrate. The superconducting thin film is employed as a zero-resistivity electrode material for a surface acoustic wave resonator with internal quality factors Q ≈ 17 000 representing a three-fold enhancement compared to identical devices with normal conducting electrodes. Superconducting operation of ≈ 400 M H z resonators is achieved to temperatures T > 7 K and electrical radio frequency powers P r f > + 9 d B m . Heterogeneously integrated single QDs couple to the resonant phononic field of the surface acoustic wave resonator operated in the superconducting regime. Position and frequency selective coupling mediated by deformation potential coupling is validated using time-integrated and time-resolved optical spectroscopy. Furthermore, acoustoelectric charge state control is achieved in a modified device geometry harnessing large piezoelectric fields inside the resonator. The hybrid QD—surface acoustic wave resonator can be scaled to higher operation frequencies and smaller mode volumes for quantum phase modulation and transduction between photons and phonons via the QD. Finally, the employed materials allow for the realization of other types of optoelectronic devices, including superconducting single photon detectors and integrated photonic and phononic circuits.

Grundkategorien moralischer Bewertung

Abstract: Als Grundkategorien moralischer BewertungBewertung, moralische lassen sich diejenigen Kategorien auffassen, die das Feld möglicher moralischer Urteile strukturieren. Da moralische Urteile sich nicht nur auf Handlungen und Handlungsregeln (Normen) erstrecken, sondern auch Motive und Absichten, Einstellungen und Dispositionen von Akteuren sowie den Charakter und die Lebensführung einer Person zum Gegenstand haben können (vgl. Birnbacher 2013, 46), können die einschlägigen Grundkategorien der moralischen Beurteilung sowohl von Handlungen und Handlungsregeln als auch von Motiven und Absichten, Einstellungen, Charakteren und Lebensweisen von (menschlichen) Individuen dienen.

Removal of cadmium from solution during the replacement of calcium carbonate by hydroxyapatite in the presence of phosphate.

Abstract: Water contamination caused by the overuse of fertilizers has become a concern in many areas throughout the last decades. The intensive use of phosphate fertilizers has led to high concentrations of phosphates in ground waters and effluents, but also to high levels of other toxic elements, especially cadmium. Cadmium can be found in high concentrations in phosphate rocks which are used to synthesize fertilizers, resulting in high concentrations of cadmium in some fertilizers that are then used on fields. Various materials have been studied for cadmium capture in solution and both calcium carbonate and apatite have shown good uptake capacities toward this element. Furthermore, calcium carbonate minerals can be replaced by apatite through a pseudomorphic dissolution-precipitation mechanism when immersed in a solution containing phosphate (Jonas et al., 2014; Klasa et al., 2013; Pedrosa et al., 2016; Wang et al., 2012). Here, we report on the capture of cadmium from solution during the replacement reaction of Carrara marble by hydroxyapatite (Wang et al., 2019). Cubes of Carrara marble have been reacted in sealed hydrothermal reactors at 200°C in solutions containing various concentrations of phosphate and cadmium for times between 4 and 60 days. The samples were then sectioned and analysed by Scanning Electron Microscopy (SEM), BackScattered Electron (BSE) imaging, Electron Dispersive X-ray Spectroscopy (EDS) and Raman Spectroscopy. The nanoscale reaction on the sample surface has been observed with in-situ Atomic Force Microscopy (AFM) in fluid flow and static solutions. The coupled dissolution-precipitation reaction observed and the capture of cadmium by the newly formed phase will be presented.References:Jonas, L., John, T., King, H.E., Geisler, T., Putnis, A., 2014. The role of grain boundaries and transient porosity in rocks as fluid pathways for reaction front propagation. Earth and Planetary Science Letters 386, 64–74. https://doi.org/10.1016/j.epsl.2013.10.050Klasa, J., Ruiz-Agudo, E., Wang, L.J., Putnis, C.V., Valsami-Jones, E., Menneken, M., Putnis, A., 2013. An atomic force microscopy study of the dissolution of calcite in the presence of phosphate ions. Geochimica et Cosmochimica Acta 117, 115–128. https://doi.org/10.1016/j.gca.2013.03.025Pedrosa, E.T., Putnis, C.V., Putnis, A., 2016. The pseudomorphic replacement of marble by apatite: The role of fluid composition. Chemical Geology 425, 1–11. https://doi.org/10.1016/j.chemgeo.2016.01.022Wang, L., Ruiz-Agudo, E., Putnis, C.V., Menneken, M., Putnis, A., 2012. Kinetics of Calcium Phosphate Nucleation and Growth on Calcite: Implications for Predicting the Fate of Dissolved Phosphate Species in Alkaline Soils. Environ. Sci. Technol. 46, 834–842. https://doi.org/10.1021/es202924fWang, M., Wu, S., Guo, J., Zhang, X., Yang, Y., Chen, F., Zhu, R., 2019. Immobilization of cadmium by hydroxyapatite converted from microbial precipitated calcite. Journal of Hazardous Materials 366, 684–693. https://doi.org/10.1016/j.jhazmat.2018.12.049