Forschungszentrum Jülich

Sustainable agriculture depends on reliable phosphorus (P) supplies, yet global reserves of mineral P fertilizers are finite. Here, we explored whether organic fertilization could serve as a viable substitute for mineral P while sustaining crop yields and soil P under changing climate conditions. Using the calibrated and validated AgroC model with decades of field data from the Bad Lauchstädt long-term experiment site in Germany (with a four-crop rotation of sugar beet, spring barley, potato, and winter wheat), we simulated crop performance and soil P dynamics from 2019 to 2100 under the RCP4.5 and RCP8.5 climate scenarios. The analysis compared five fertilization strategies: mineral fertilization (MIN), two farmyard manure rates (FYM_20 and FYM_30), and two optimized manure regimes (FYM_37 and FYM_37 +N). Results showed that fertilization strategy had a far greater influence on soil P and yields than the projected climate scenarios. Low manure inputs (FYM_20) led to steady P depletion and yield loss, whereas FYM_30 and FYM_37 reduced winter wheat yield losses to 45% and 30% below MIN levels, respectively, while achieving comparable or superior yields for barley, potato, and sugar beet. Winter wheat required modest mineral N supplementation (∼15 kg N ha⁻¹) in FYM_37 +N to achieve optimal yields, while potato, barley, and sugar beet performed well under manure-only management. Warmer conditions under RCP8.5 increased P depletion by 10–15% relative to RCP4.5, but this effect remained minor compared with fertilization management. Notably, higher manure application rates were linked to lower cumulative P leaching. Among treatments, FYM_37_N performed best, with total P losses only 1.5–2% higher than those of MIN (3.77–4.82 kg P ha⁻¹ for MIN under RCP4.5 and RCP8.5). Our results suggest that optimized organic fertilization can effectively replace mineral P inputs, maintain crop yields, and enhance resilience in long-term cropping systems under climate change. • Optimized manure rates (FYM_37) sustain crop yields and soil P. • Climate effects on soil P are minor compared to fertilization strategies but increase P depletion under RCP8.5. • Additional mineral N beside organic amendment enhances winter wheat yield • Manure effectively substitutes mineral P fertilizers in long-term cropping systems.

• Extend optimal experimental design for guaranteed parameter estimation to LLE systems • Employ rigorous calculations for the LLE using the Baker’s criterion • Avoid problematic parameter values, which may lead to erroneous predictions • Present proof-of-concept case study, reducing the parameter uncertainty by at least 10.3924909 % Semi-empirical models for LLE are essential for chemical process design but rely on experimental data for parameter estimation. In the face of high experimental costs, determining an informative experimental plan is crucial for constructing and validating these models efficiently. OED for (bounded-error) guaranteed GPE is a valuable approach to planning LLE experiments, but it has been limited to systems with simple input-output relations. We extend this method to systems whose input-output relation is implicitly given by an equation system with additional semi-infinite constraints, which corresponds to the rigorous computation of an LLE. Excess Gibbs free energy models are highly flexible but can predict spurious phase splits due to (i) using non-rigorous computations, or (ii) parameter values that are problematic in the sense that they lead to erroneous model behavior. To mitigate these issues in experiment planning, we (i) employ rigorous calculations using Baker’s criterion, and (ii) enforce additional requirements, based on [Mitsos et al. Chem. Eng. Sci., 64(3):548–559, 2009] to exclude parameter values that lead to erroneous model behavior. We solve the resulting problem using (generalized) semi-infinite programming techniques and provide a proof of concept using the Redlich-Kister model to plan the OED to reduce parameter uncertainty. Our approach successfully avoids wrong predictions due to problematic parameter values and computes an experimental design that significantly reduces the predicted parameter uncertainty. However, our method is computationally demanding, necessitating advancements in numerical methods for practical applications involving multiple parameters or more complex excess models.

Fluorescent protein (FP) variants have recently emerged as promising intracellular nitric oxide (NO) sensors based on NO-induced fluorescence loss due to cysteine S-nitrosylation - the covalent addition of a nitroso group to a cysteine thiol within a protein to form an S-nitrosothiol. Here, we investigate the mechanisms underlying this fluorescence loss using a combined experimental and computational approach. We focus on mTagBFP2, a blue fluorescent protein that undergoes a 70% reduction in fluorescence quantum yield and lifetime upon exposure to micromolar NO concentrations. We discriminate, through mutagenesis, the contributions of two key cysteine residues and propose an unprecedented excitation energy transfer (EET) from the mTagBFP2 chromophore to the S-nitroso groups as a potential quenching mechanism. Our EET efficiency calculations incorporate full couplings, the effects of the surrounding protein and solvent, and molecular dynamics-based configurational flexibility. The computed EET efficiencies broadly align with experimental observations, with remaining discrepancies for which we advance potential explanations. Our findings establish a mechanistic basis for NO-induced fluorescence loss in mTagBFP2, providing guidelines for the rational design of next-generation NO-sensitive FPs. Moreover, they suggest that analogous S-nitrosylation-driven quenching mechanisms could be operative in other FPs with exposed cysteine residues, underscoring the risk of artefacts in cellular imaging under physiological NO levels.

Magnetic hopfions are 3D topological solitons - knotted, vortex-like spin configurations. In chiral magnets, hopfions can appear as isolated structures or they can be linked to skyrmion strings. Previous studies employed a sophisticated protocol and a special sample geometry to nucleate such hopfions linked to one or a few skyrmion strings. Here, we introduce an electric-current-assisted nucleation protocol that is simple and independent of the sample shape and size. The resulting hopfions exhibit extraordinary stability in the presence of both positive and negative magnetic fields, in perfect agreement with micromagnetic simulations. We also present a comprehensive framework for classifying hopfions, skyrmions, and merons by deriving the corresponding homotopygroup.

Permanent magnets containing rare earth elements are essential components for the electrification of society. Ce(Co 1-x Cu x ) 5 permanent magnets are a model system known for their substantial coercivity, yet the underlying mechanism remains unclear. Here, we investigate Ce(Co 0.8 Cu 0.2 ) 5.4 magnets with a coercivity of ∼1 T. Using transmission electron microscopy (TEM) and atom probe tomography (APT), we identify a nanoscale cellular structure formed by spinodal decomposition. Cu-poor cylindrical cells (∼5-10 nm in diameter, ∼20 nm long) have a disordered CeCo 5 -type structure and a composition Ce(Co 0.9 Cu 0.1 ) 5.3 . Cu-rich cell boundaries are ∼ 5 nm thick and exhibit a modified CeCo 5 structure, with Cu ordered on the Co sites and a composition Ce(Co 0.7 Cu 0.3 ) 5.0 . Micromagnetic simulations demonstrate that the intrinsic Cu concentration gradients up to 12 at.% Cu/nm lead to a spatial variation in magnetocrystalline anisotropy and domain wall energy, resulting in effective pinning and high coercivity. Compared to Sm 2 Co 17 -type magnets, Ce(Co 0.8 Cu 0.2 ) 5.4 displays a finer-scale variation of conventional pinning with lower structural and chemical contrast in its underlying nanostructure. The identification of nanoscale chemical segregation in nearly single-phase Ce(Co 0.8 Cu 0.2 ) 5.4 magnets provides a microstructural basis for the long-standing phenomenon of "giant intrinsic magnetic hardness" in systems such as SmCo 5-x M x , highlighting avenues for designing rare-earth-lean permanent magnets via controlled nanoscale segregation.

Bio-based carboxylic acids are key platform chemicals for a circular economy, offering sustainable alternatives to fossil-derived products. Yet, high substrate and processing costs, along with narrow profit margins, restrict industrial-scale bioproduction. In situ product removal (ISPR) holds the potential to increase productivity and yield in fermentations by circumventing product inhibition. Thus, it presents a promising process intensification measure to bridge the commercial gap between bio-based and petrochemical platform chemicals. One effective method for product recovery is reactive extraction with trioctylamine. In the present study, this method was applied to itaconic acid (ITA) fermentations with Ustilago cynodontis. First, the successful operation of dispersion-based apparatuses for reactive extraction was proven using small-scale mixer-settlers, with 1-octanol and the biocompatible 2-octanone as diluents. We then developed an improved feeding profile, lowering byproduct formation by 72%. Subsequently, we demonstrated the feasibility of ISPR using a perfusion bioreactor with an external membrane coupled to reactive extraction and back-extraction. After 233h of fermentation, the total amount of ITA produced was increased by 26%, and productivity was 21% higher compared to extended-batch fermentations. However, the yield was only slightly improved by 5%. Ultimately, we identified product toxicity far below the maximum titer of 80g as a key bottleneck in ISPR fermentations with U.cynodontis. The results underscore the potential of ISPR and warrant further investigation in this field.

Interlayer engineering is widely used to improve charge storage in layered transition metal dichalcogenides, yet most studies rely on nanosized materials where the effects of interlayer expansion and particle downsizing are intertwined. Here, molecular pillaring is translated to bulk molybdenum disulfide (MoS2) using a top-down strategy. Chemical pre-reduction with butyllithium enables exfoliation and restacking in the presence of hexanediammonium (HDA) molecules, forming a pillared MoS2-HDA structure with an expanded interlayer spacing of 0.98 nm while preserving the bulk particle morphology and specific surface area. Electrochemical analysis reveals that improved rate capability primarily originates from the chemical activation associated with the pre-reduction step rather than from interlayer expansion itself. Operando X-ray diffraction and electrochemical dilatometry show that bulk MoS2 undergoes solvent co-intercalation in diglyme electrolyte, leading to pronounced lattice expansion and electrode swelling. In contrast, pillared MoS2-HDA suppresses solvent cointercalation despite its larger interlayer spacing, demonstrating that interlayer expansion alone does not dictate solvent co-intercalation in layered electrodes.

In order to make garnet-based all-solid-state batteries (ASSBs) attractive for industrial applications, their rate capability has to be significantly improved. Recently, cubic Li<sub>6.4</sub>Ga<sub>0.2</sub>La<sub>3</sub>Zr<sub>2</sub>O<sub>12</sub> (LLZO:Ga) was found to have the highest total ionic conductivity of any oxide solid-state electrolyte by far, reaching up to 2 × 10<sup>-3</sup> S/cm at room temperature. Since the rate performance of composite cathodes is directly linked to their ionic conductivity, LLZO:Ga is an ideal solid-state electrolyte for high-performance ASSBs. However, careful material selection is required for the fabrication of such ceramic composite cathodes at elevated temperatures in order to avoid incompatibility issues that could lead to low electrochemical performance. We therefore systematically studied the co-sintering behavior of cubic LLZO:Ga in combination with common cathode active materials, including LiCoO<sub>2</sub> (LCO), LiNi<sub>1/3</sub>Mn<sub>1/3</sub>Co<sub>1/3</sub>O<sub>2</sub> (NCM111), and LiNi<sub>0.8</sub>Mn<sub>0.1</sub>Co<sub>0.1</sub>O<sub>2</sub> (NCM811). The analyses were performed using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. The experimental conditions were chosen to enable a direct comparison with our previous study on Li<sub>6.45</sub>La<sub>3</sub>Zr<sub>1.6</sub>Ta<sub>0.4</sub>Al<sub>0.05</sub>O<sub>12</sub> (LLZO:Ta). For the first time, we were thus able to elucidate the impact of different LLZO compositions on material compatibility. While most of the observed secondary phases were similar to those found for LLZO:Ta-based composites, a more severe degradation of the cubic LLZO:Ga structure itself was observed, reducing its conductivity and thus limiting the performance of the final cell. Consequently, the processing window for producing LLZO:Ga-based composite cathodes is even narrower than for LLZO with other dopants, thus requiring careful tailoring and tight control over the processing conditions when manufacturing garnet-based ASSBs.