FH Aachen

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.

ABSTRACT Flowchart of a model paper recycling mill water circuit, highlighting recycling, recovery, and discharge pathways. Icons indicate each unit (from http://www.flaticon.com). This study investigates nanofiltration (NF) and reverse osmosis (RO) treatment of the liquid fraction from digestate of short-fiber residues from paper recycling mills, focusing on water reuse and ammonium (NH4-N) recovery. NF removed up to 86% chemical oxygen demand (COD) and fully retained phosphorus (Ptot), but separated only 40–55% of total nitrogen (Ntot) and NH4-N. RO performed better, removing 96% COD, 86% NH4-N and Ntot, while fully retaining Ptot. RO permeate met the freshwater quality for paper recycling, with small NH4-N remaining. To improve NH4-N recovery, natural zeolite was tested with RO in three scenarios: treating the liquid fraction of digestate, RO retentate, and RO permeate. The highest NH4-N adsorption (79%, 7.8 mg/g) occurred with RO retentate, and the highest desorption (53%, 2.9 mg/g) with RO permeate. Adsorption performance varied with NH4-N concentration and pretreatment, with higher NH4-N levels leading to greater adsorption. COD was also reduced by up to 70% during adsorption. RO treatment of digestate in a model paper mill (0.7 Mt/year production capacity) could recover about 38,000 m3 of water annually, saving 71,000 €. Combined savings from water reuse and avoided digestate disposal could alone reach 0.2 million € annually.

In this study, we present the fabrication and characterization of a miniaturized, single-chip electrochemical sensor implemented on a silicon/silicon dioxide platform. The device incorporates a nanocrystalline graphite (NCG) working electrode and gold reference and counter electrodes, all monolithically integrated on the same substrate. This configuration provides a compact and reliable sensing architecture, combining the electrochemical advantages of carbon with the precision and reproducibility of microfabrication. A molecularly imprinted biopolymer (MIP) layer for glyphosate (GLY) detection was subsequently formed by electrodepositing chitosan (CS) in the presence of the target analyte, directly onto the NCG surface. The resulting sensor exhibited high sensitivity and selectivity, allowing indirect detection of GLY at concentrations as low as 0.015 ppb. Validation tests demonstrated excellent recovery rates in spiked water samples, highlighting the sensor’s potential for environmental monitoring applications. This integrated platform offers a promising approach for the sensitive, portable, and cost-effective detection of GLY residues.

This study delves into the development and application of a Key Performance Indicators (KPIs)-driven framework tailored for Design Organization Approval (DOA) and Production Organization Approval (POA) officers in the airline industry. It aims to elucidate how strategic alignment of KPIs with organizational objectives can significantly enhance the efficiency, compliance, and innovation in airline design and production processes. Employing a mixed-methods research approach, the study combines quantitative data analysis with qualitative insights from industry surveys, case studies, and direct observations. The findings reveal that a well-structured KPI framework not only optimizes operational processes but also fosters a culture of continuous improvement and strategic decision-making. By systematically analyzing various KPIs related to design and production efficiency, quality assurance, regulatory compliance, project management, innovation, supplier management, sustainability, and financial performance, the research underscores the pivotal role of KPIs in driving industry excellence. The study offers actionable insights for DOA and POA officers, suggesting the integration of KPIs into strategic planning and day-to-day operations as a means to navigate the complexities of modern aviation and achieve organizational goals. This research contributes to the existing body of knowledge by highlighting the multidimensional impact of KPIs and proposing a dynamic, adaptable framework for continuous operational enhancement in the highly regulated airline industry.

Cyclase-associated protein 2 (CAP2) is a synaptic actin-binding protein involved in cofilin-mediated spine remodelling, Alzheimer’s Disease synaptic failure and myofibril maintenance, indicating its potential involvement in motor neuron disease (MND). This study examined cerebrospinal fluid (CSF) levels of CAP2 in 60 patients with MND and 40 healthy controls (HC) to assess its diagnostic and prognostic value and its relationship with neuronal, glial and synaptic markers. Glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), phosphorylated and total tau (p-Tau 181, t-Tau), CAP2 and synaptosomal-associated protein 25 (SNAP-25) were quantified using ELISA, Lumipulse and SIMOA platforms. MND patients displayed increased GFAP, NfL, t-Tau, p-Tau 181 levels and CAP2 while SNAP-25 was reduced. CAP2 correlated with tau markers, but not with NfL or GFAP. Unlike NfL, which was higher in upper motor neuron–predominant cases and predicted faster progression and poorer survival, CAP2 did not vary with disease subtypes or severity. The study showed that CAP2 is associated with MND independently from neuronal, glial and presynaptic dysfunction. Integrating CAP2 into multi-marker panels could enhance understanding of synaptic pathology in MND.

We present GATE version 10, a major evolution of the open-source Monte Carlo simulation application for medical physics, built on Geant4. This release marks a transformative evolution, featuring a modern Python-based user interface, enhanced multithreading and multiprocessing capabilities, the ability to be embedded as a library within other software, and a streamlined framework for collaborative development. In this Part 1 paper, we outline GATE's position among other Monte Carlo codes, the core principles driving this evolution, and the robust development cycle employed. We also detail the new features and improvements. Part 2 will focus on the architectural innovations and technical challenges. By combining an open, collaborative framework with cutting-edge features, such a Monte Carlo platform supports a wide range of academic and industrial research, solidifying its role as a critical tool for innovation in medical physics.

IntroductionPulmonary artery (PA) cannulation is emerging as a method for concurrent cardiac and respiratory failure, but limited data exists on how cannula positioning, particularly cannula tip angle, affects perfusion symmetry. Due to varying pulmonary bifurcation geometry between patients, ensuring even distribution of oxygen-saturated blood becomes critical. This computational fluid dynamics (CFD) study investigated the effects of cannula positioning and angles on oxygen delivery within the PA using 6 different configurations.MethodAn idealized PA geometry based on a CT scan was constructed including the 6 different cannula configurations: two straight (short and long) and four angled (5° and 10° toward either pulmonary branch). Simulations assumed laminar, steady-state flow at 6L/min total (50% ECMO contribution). Oxygen transport was modeled as a passive scalar with 75% saturation from the heart and 100% from the cannula. Perfusion symmetry was quantified using the absolute difference in mean oxygen saturation (ΔSaO2) and partial pressure (ΔpO2) between the right (RPA) and left pulmonary arteries (LPA).ResultsCannula positioning and angulation influences oxygen distribution within the PA. Straight-tipped cannulas favored LPA-sided flow due to the natural geometry of the pulmonary artery (ΔSaO2 = 12.9-15.1%). A 5° RPA directed angulation achieved the most symmetric distribution (ΔSaO2 = 9.2%, ΔpO2 = 14.2 mmHg), whereas greater or opposite angulations increased flow asymmetry.ConclusionMinor cannula tip angulation, specifically 5° deflection towards the RPA, enhances bilateral PA oxygenation without increasing ECMO flow, providing a simple yet effective strategy for optimizing pulmonary ECMO perfusion.

Bacterial cellulose (BC) is a promising biomaterial for medical and biotechnological applications. However, microbial contaminants and their metabolic residues remain a critical limitation for its clinical use. Many of the BC purity tests are labor-intensive and time-consuming. This study investigates the feasibility of using laser-induced fluorescence (LIF) spectroscopy for monitoring microbial contamination in BC. BC samples were obtained from a Medusomyces gisevii consortium and subjected to various purification protocols (alkaline, detergent and oxidative treatments). LIF spectra were recorded across 220-290nm excitation wavelengths and analyzed chemometrically. For better interpretation of the results, the same samples were examined by laser scanning confocal microscopy (LSM). The results reveal that both native and treated BC samples exhibit fluorescence features associated with tryptophan and tyrosine, indicative of microbial residues. Treatment with NaOH effectively reduced tryptophan-associated signals, while hydrogen peroxide diminished tyrosine-related fluorescence. None of the purification strategies completely eliminated these signals. A good correlation between the LIF and the more labor-consuming LSM data was observed. LIF showed the capability of rapid and reliable differentiation between treatment variants and provided spectral fingerprints linked to residual contamination. Future work may focus on standardizing LIF-based diagnostic protocols and integrating them into biotechnological workflows for contamination monitoring.

• Two-dimensional concentration measurements using Raman spectroscopy. • Non-invasive measurements of mass transfer during droplet formation. • Specially designed optical system to reduce spherical aberrations • Visualization of mass transfer in the system water/acetonitrile/toluene. • Qualitative progression of the droplet concentration over time. A novel two-dimensional Raman spectroscopy measurement setup is developed to visualize mass transfer during droplet formation and applied to the water/acetonitrile/toluene system. This setup enables direct observation of local solute contents. Experiments were conducted using 2 mm and 4 mm droplets with an initial acetonitrile content of 10 wt%. The results are qualitatively consistent with findings reported in the literature for similar systems. Initial calibration measurements using single-phase systems demonstrated linear correlations between measured intensities and solute contents in both phases, though a baseline shift in the organic phase was attributed to the presence of toluene. Applying these correlations to droplet formation experiments resulted in an overestimation of local acetonitrile contents. Future work will focus on further refining the quantification capabilities of the measurement setup.