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  • Article
    Open Access
    The Stokes–Einstein–Sutherland Equation at the Nanoscale Revisited
    (2023-10-08) Baer, Andreas; Wawra, Simon E.; Bielmeier, Kristina; Uttinger, Maximilian J.; Smith, David M.; Peukert, Wolfgang; Walter, Johannes; Smith, Ana‐Sunčana

    The Stokes–Einstein–Sutherland (SES) equation is at the foundation of statistical physics, relating a particle's diffusion coefficient and size with the fluid viscosity, temperature, and the boundary condition for the particle‐solvent interface. It is assumed that it relies on the separation of scales between the particle and the solvent, hence it is expected to break down for diffusive transport on the molecular scale. This assumption is however challenged by a number of experimental studies showing a remarkably small, if any, violation, while simulations systematically report the opposite. To understand these discrepancies, analytical ultracentrifugation experiments are combined with molecular simulations, both performed at unprecedented accuracies, to study the transport of buckminsterfullerene C60 in toluene at infinite dilution. This system is demonstrated to clearly violate the conditions of slow momentum relaxation. Yet, through a linear response to a constant force, the SES equation can be recovered in the long time limit with no more than 4% uncertainty both in experiments and in simulations. This nonetheless requires partial slip on the particle interface, extracted consistently from all the data. These results, thus, resolve a long‐standing discussion on the validity and limits of the SES equation at the molecular scale.

  • Article
    Open Access
    Magnetic Removal of Micro‐ and Nanoplastics from Water—from 100 nm to 100 µm Debris Size
    (2023-10-24) Gaß, Henrik; Kloos, Tonya M.; Höfling, Anna; Müller, Lukas; Rockmann, Linda; Schubert, Dirk W.; Halik, Marcus

    Clean water is one of the most important resources of the planet but human‐made contamination with diverse pollutants increases continuously. Microplastics (<5 mm diameter) which can have severe impacts on the environment, are present worldwide. Degradation processes lead to nanoplastics (<1 µm), which are potentially even more dangerous due to their increased bioavailability. State‐of‐the‐art wastewater treatment plants show a deficit in effectively eliminating micro‐ and nanoplastics (MNP) from water, particularly in the case of nanoplastics. In this work, the magnetic removal of three different MNP types across three orders of magnitude in size (100 nm–100 µm) is investigated systematically. Superparamagnetic iron oxide nanoparticles (SPIONs) tend to attract oppositely charged MNPs and form aggregates that can be easily collected by a magnet. It shows that especially the smallest fractions (100–300 nm) can be separated in ordinary high numbers (1013 mg−1 SPION) while the highest mass is removed for MNP between 2.5 and 5 µm. The universal trend for all three types of MNP can be fitted with a derived model, which can make predictions for optimizing SPIONs for specific size ranges in the future.

  • Article
    Open Access
    Electrochemical Realization of 3D Interconnected MoS3/PPy Nanowire Frameworks as Sulfur‐Equivalent Cathode Materials for Li‐S Batteries
    (2023-01-30) Yu, Hongtao; Siebert, Andreas; Mei, Shilin; Garcia‐Diez, Raul; Félix, Roberto; Quan, Ting; Xu, Yaolin; Frisch, Johannes; Wilks, Regan G.; Bär, Marcus; Pei, Chun; Lu, Yan

    The development of freestanding and binder‐free electrode is an effective approach to perform the inherent capacity of active materials and promote the mechanism study by minimizing the interference from additives. Herein, we construct a freestanding cathode composed of MoS3/PPy nanowires (NWs) deposited on porous nickel foam (NF) (MoS3/PPy/NF) through electrochemical methods, which can work efficiently as sulfur‐equivalent cathode material for Li‐S batteries. The structural stability of the MoS3/PPy/NF cathode is greatly enhanced due to its significant tolerance to the volume expansion of MoS3 during the lithiation process, which we ascribe to the flexible 3D framework of PPy NWs, leading to superior cycling performance compared to the bulk‐MoS3/NF reference. Eliminating the interference of binder and carbon additives, the evolution of the chemical and electronic structure of Mo and S species during the discharge/charge was studied by X‐ray absorption near‐edge spectroscopy (XANES). The formation of lithium polysulfides was excluded as the driving cathode reaction mechanism, suggesting the great potential of MoS3 as a promising sulfur‐equivalent cathode material to evade the shuttle effect for Li‐S batteries. The present study successfully demonstrates the importance of structural design of freestanding electrode enhancing the cycling performances and revealing the corresponding mechanisms.

  • Article
    Open Access
    Hypoxia Attenuates Pressure Overload‐Induced Heart Failure
    (2024-02-06) Froese, Natali; Szaroszyk, Malgorzata; Galuppo, Paolo; Visker, Joseph R.; Werlein, Christopher; Korf‐Klingebiel, Mortimer; Berliner, Dominik; Reboll, Marc R.; Hamouche, Rana; Gegel, Simona; Wang, Yong; Hofmann, Winfried; Tang, Ming; Geffers, Robert; Wende, Adam R.; Kühnel, Mark P.; Jonigk, Danny D.; Hansmann, Georg; Wollert, Kai C.; Abel, E. Dale; Drakos, Stavros G.; Bauersachs, Johann; Riehle, Christian
    Background

    Alveolar hypoxia is protective in the context of cardiovascular and ischemic heart disease; however, the underlying mechanisms are incompletely understood. The present study sought to test the hypothesis that hypoxia is cardioprotective in left ventricular pressure overload (LVPO)–induced heart failure. We furthermore aimed to test that overlapping mechanisms promote cardiac recovery in heart failure patients following left ventricular assist device‐mediated mechanical unloading and circulatory support.

    Methods and Results

    We established a novel murine model of combined chronic alveolar hypoxia and LVPO following transverse aortic constriction (HxTAC). The HxTAC model is resistant to cardiac hypertrophy and the development of heart failure. The cardioprotective mechanisms identified in our HxTAC model include increased activation of HIF (hypoxia‐inducible factor)‐1α–mediated angiogenesis, attenuated induction of genes associated with pathological remodeling, and preserved metabolic gene expression as identified by RNA sequencing. Furthermore, LVPO decreased Tbx5 and increased Hsd11b1 mRNA expression under normoxic conditions, which was attenuated under hypoxic conditions and may induce additional hypoxia‐mediated cardioprotective effects. Analysis of samples from patients with advanced heart failure that demonstrated left ventricular assist device–mediated myocardial recovery revealed a similar expression pattern for TBX5 and HSD11B1 as observed in HxTAC hearts.

    Conclusions

    Hypoxia attenuates LVPO‐induced heart failure. Cardioprotective pathways identified in the HxTAC model might also contribute to cardiac recovery following left ventricular assist device support. These data highlight the potential of our novel HxTAC model to identify hypoxia‐mediated cardioprotective mechanisms and therapeutic targets that attenuate LVPO‐induced heart failure and mediate cardiac recovery following mechanical circulatory support.

  • Article
    Open Access
    Synthesis of BaZrS3 and BaS3 Thin Films: High and Low Temperature Approaches
    (MDPI, 2024-03-09) Freund, Tim; Jamshaid, Sumbal; Monavvar, Milad; Wellmann, Peter

    Current research efforts in the field of the semiconducting chalcogenide perovskites are directed towards the fabrication of thin films and subsequently determine their performance in the photovoltaic application. These efforts are motivated by the outstanding properties of this class of materials in terms of stability, high absorption coefficient near the band edge and no significant health concerns compared to their halide counterparts. The approach followed here is to use stacked precursor layers and is adopted from other chalcogenide photovoltaic materials like the kesterites and chalcopyrites. The successful synthesis of BaZrS3 from stacked layers of BaS and Zr and annealing at high temperatures (~1100 °C) with the addition of elemental sulfur is demonstrated. However, the film shows the presence of secondary phases and a flawed surface. As an alternative to this, BaS3 could be used as precursor due to its low melting point of 554 °C. Previously, the fabrication of BaS3 films was demonstrated, but in order to utilize them in the fabrication of BaZrS3 thin films, their microstructure and processing are further improved in this work by reducing the synthesis temperature to 300 °C, resulting in a smoother surface. This work lays the groundwork for future research in the fabrication of chalcogenide perovskites utilizing stacked layers and BaS3.

  • Article
    Open Access
    A Novel Approach for Rapid Material Library Generation Using Laser‐Remelting
    (2023-12-29) Gaag, Tobias; Heidowitzsch, Maximilian; Galgon, Florian; Körner, Carolin; Zenk, Christopher H.

    Cost‐ and time‐demanding trial‐and‐error methods have been the historical route for alloy development. A combinatorial approach can significantly simplify and accelerate the development process by characterization of composition dependent properties on material libraries, which are specimens or sets of specimens that map out a certain composition space, often employing composition profiles. Herein, a promising production method for such a material library is proposed: laser‐remelting of stacked blocks of different compositions is evaluated for its suitability to produce material libraries, using the ternary CrCoNi system for a proof‐of‐concept. The composition profiles of the successfully created CrCoNi material library were measured by electron probe micro analysis. The intermixing has a length of about 2.5 mm. An analytical model describing the intermixing process is proposed and shows value in the estimation of the intermixing length after the first melting step. The comparison of the experimental microstructure observations from this work and from literature shows mostly good agreement with some deviations related to microsegregation and finite quenching cooling rates, which is supported by thermodynamic calculations regarding phase stability. In the single‐phase region, the mechanical properties as measured via microhardness indentation are discussed as potential candidates for model validation.

  • Article
    Open Access
    Review and Prospects of PEM Water Electrolysis at Elevated Temperature Operation
    (2023-12-18) Bonanno, Marco; Müller, Karsten; Bensmann, Boris; Hanke‐Rauschenbach, Richard; Aili, David; Franken, Tanja; Chromik, Andreas; Peach, Retha; Freiberg, Anna T. S.; Thiele, Simon

    Polymer electrolyte membrane water electrolyzers (PEMWE) are currently restricted to an operating temperature range between 50 to 80 °C. This review shows that elevated temperature (ET) above 90 °C can be advantageous with respect to i) reduced cell voltages, ii) a reduction of catalyst loading or possibly the employment of less noble electrocatalysts, and iii) a greater potential for waste heat utilization when the electrolyzer is operated in exothermal mode (when the cell voltage is higher than the thermoneutral voltage). Together with presenting an overview of the materials and components utilized in elevated temperature PEMWE under liquid and steam operation, this article summarizes the experimental and modeling performances reported to date, highlights the challenges ahead, and suggests aspects, which will need to be considered to improve the performance at elevated temperature. Key points, which arise from this work are the extensive need of re‐assessing the material selection both for the cell components and also at a system level, the effects and optimization of working with steam operation, and in the long run, the need for techno‐economic analyses to ultimately assess whether efficiency gains will truly translate to a cost‐effective technology alternative.

  • Article
    Open Access
    Gold Nanoparticles in Disulfide Based Polymer Matrices: Size, Structure and Responsivity
    (2023-12-10) Wagner, Maximilian; Krieger, Anja; Gröhn, Franziska

    A disulfide‐based polymer is used as a template for the synthesis of gold nanoparticles. Three different syntheses are tested: The simultaneous formation of gold nanoparticles and the disulfide polymer (A), the loading of a disulfide polymer matrix with HAuCl4 and then reducing with hydrazine (B), and reducing HAuCl4 with hydrazine in the presence of a cross‐linking thiol follows by oxidative coupling of another thiol to the previously formed structures via disulfide bond formation (C). The ratio of the water‐insoluble pentaerythritol tetrakis(3‐mercaptopropionate) (PETMP) and the water‐soluble acids mercaptopropionic acid or mercaptosuccinic acid (MPA or MSA) are varied. The resulting gold nanostructures differ significantly with respect to their synthesis reaching from isolated particles to networks and raspberry‐like structures. Due to the formation of disulfide bonds during the syntheses, the response of the hybrid nanoparticles to UV light and ultrasound is investigated, showing a breakdown of micrometer‐sized structures to 50 nm‐sized hybrid structures in aqueous solution.

  • Article
    Open Access
    Health Literacy and Environmental Risks Focusing Air Pollution: Results from a Cross-Sectional Study in Germany
    (MDPI, 2024-03-19) Pfleger, Elisabeth; Drexler, Hans; Lutz, Regina

    (1) Background: Environmental risks such as air pollutants pose a threat to human health and must be communicated to the affected population to create awareness, such as via health literacy (HL); (2) Methods: We analyzed HL in the context of environmental health risks, including sources of information and prior knowledge, in a sample from the German general population using Kendall’s rank correlations, regression analyses, and explorative parallel mediation analysis; (3) Results: The survey included 412 German participants aged between 18 and 77. HL was found to be problematic to inadequate. The internet, family and friends, and newspapers were the most frequently cited sources of information. Mobile apps were mostly unknown but were requested by sample subjects. Although subjects expressed environmental concerns and exhibited rather good levels of knowledge, the majority perceived no risk to human health and rated air quality quite positively. Knowledge on particulate matter, the term “ultrafine particles”, and protective measures was found to be rather low. HL was associated with the use of newspapers and commercials as sources of information. The relationship between age and HL is fully mediated by the use of newspapers and information from TV commercials; (4) Conclusions: HL should be promoted by raising awareness of the health effects of environmental pollutants. In particular, the information channels preferred by the affected population should be used and further information opportunities such as apps should be publicized, e.g., through campaigns. An improved HL can assist policy makers in creating a healthier environment by empowering individuals to become more environmentally aware and protect their own health. This, in turn, has the potential to reduce health-related costs.

  • Article
    Open Access
    A Carbon‐Stabilized Austenitic Steel with Lower Hydrogen Embrittlement Susceptibility
    (2023-10-27) Khanchandani, Heena; Zeiler, Stefan; Strobel, Lucas; Göken, Mathias; Felfer, Peter

    High‐strength steels are susceptible to H‐induced failure, which is typically caused by the presence of diffusible H in the microstructure. The diffusivity of H in austenitic steels with face‐centered cubic (fcc) crystal structure is slow. The austenitic steels are hence preferred for applications in the hydrogen‐containing atmospheres. However, the fcc structure of austenitic steels is often stabilized by the addition of Ni, Mn, or N, which are relatively expensive alloying elements to use. Austenite can kinetically also be stabilized using C. Herein, an approach is applied to a commercial cold work tool steel, where C is used to fully stabilize the fcc phase. This results in a microstructure consisting of only austenite and M7C3 carbide. An exposure to H by cathodic hydrogen charging exhibits no significant influence on the strength and ductility of the C‐stabilized austenitic steel. While this material is only a prototype based on an existing alloy of different purposes, it shows the potential for low‐cost H‐resistant steels based on C‐stabilized austenite.

  • Article
    Open Access
    Employee acceptance of digital monitoring systems while working from home
    (2023-10-10) Wieser, Luisa; Abraham, Martin

    Digitalisation and COVID‐19 led to an expansion of remote work arrangements, raising the question of whether and how employers should monitor remote workplaces. However, before the implementation of monitoring methods, it is important to consider employees' acceptance of this approach. Therefore, we contribute to current research on electronic performance monitoring by empirically investigating employees' evaluations of performance monitoring at home. This paper presents an analysis of how certain monitoring technologies for work‐from‐home arrangements are perceived as undesirable and whether other job aspects can compensate for these unattractive monitoring components. Using an experimental factorial survey design, German employees evaluated remote work arrangements with randomly varying characteristics. We show that respondents accept a certain degree of monitoring at home but increasingly reject monitoring systems as they become more invasive. However, in some cases, the negative impact of monitoring at home can be mitigated by certain incentives, such as money or the purpose of monitoring.

  • Article
    Open Access
    Risk of developing psoriatic arthritis in psoriasis cohorts with arthralgia: exploring the subclinical psoriatic arthritis stage
    (EULAR, 2024-04-10) Zabotti, Alen; Fagni, Filippo; Gossec, Laure; Giovannini, Ivan; Sticherling, Michael; Tullio, Annarita; Baraliakos, Xenofon; De Marco, Gabriele; De Vita, Salvatore; Errichetti, Enzo; Quartuccio, Luca; Silvagni, Ettore; Smolen, Josef S; Tinazzi, Ilaria; watad, abdulla; Schett, Georg; McGonagle, Dennis G; Simon, David
    Objective

    Subjects with subclinical psoriatic arthritis (PsA), defined as the presence of arthralgia in psoriasis (PsO), are at higher risk of PsA but scant real-world data exist. Our aims were to (1) estimate the probability of PsA development in subclinical PsA, (2) characterise subclinical PsA symptoms and (3) determine the clinical patterns at PsA diagnosis.

    Methods

    Patients with PsO, mainly subclinical PsA, were evaluated longitudinally in two European cohorts. The key outcome was new-onset PsA. Musculoskeletal symptoms including inflammatory and non-inflammatory symptoms before PsA diagnosis were collected. Occurrence of PsA was analysed with survival analysis and cumulative incidence functions (CIFs).

    Results

    384 patients with PsO were included with a mean follow-up of 33.0 (±20.9) months. 311 of 384 (80.9%) had subclinical PsA with a PsA incidence rate of 7.7 per 100 patient-years. Subclinical PsA displayed a higher risk of PsA development compared with PsO (HR=11.7 (95% CI 1.57 to 86.7), p=0.016). The probability of new-onset PsA estimated by the CIF was 9.4% (95% CI 4.7% to 10.6%) at month 12 and 22.7% (95% CI 17.2% to 28.6%) at month 36. 58.9% of cases reported inflammatory symptoms in the months immediately prior to PsA diagnosis but prior non-inflammatory symptoms were evident in 83.9% prior to PsA diagnosis. Peripheral joint swelling was the predominant PsA presentation pattern (82.1%).

    Conclusions

    The probability of PsA development among subclinical PsA was relatively high, emphasising the importance of emergent musculoskeletal symptoms when aiming for PsA prevention. Joint swelling was the dominant feature in new-onset PsA, likely reflecting clinical confidence in recognising joint swelling.

  • Article
    Open Access
    Comparison of Extracellular Vesicles from Induced Pluripotent Stem Cell-Derived Brain Cells
    (MDPI, 2024-03-22) Xavier, Gabriela; Navarrete Santos, Alexander; Hartmann, Carla; Santoro, Marcos L.; Flegel, Nicole; Reinsch, Jessica; Majer, Annika; Ehrhardt, Toni; Pfeifer, Jenny; Simm, Andreas; Hollemann, Thomas; Belangero, Sintia I.; Rujescu, Dan; Jung, Matthias

    The pathophysiology of many neuropsychiatric disorders is still poorly understood. Identification of biomarkers for these diseases could benefit patients due to better classification and stratification. Exosomes excreted into the circulatory system can cross the blood–brain barrier and carry a cell type-specific set of molecules. Thus, exosomes are a source of potential biomarkers for many diseases, including neuropsychiatric disorders. Here, we investigated exosomal proteins produced from human-induced pluripotent stem cells (iPSCs) and iPSC-derived neural stem cells, neural progenitors, neurons, astrocytes, microglia-like cells, and brain capillary endothelial cells. Of the 31 exosome surface markers analyzed, a subset of biomarkers were significantly enriched in astrocytes (CD29, CD44, and CD49e), microglia-like cells (CD44), and neural stem cells (SSEA4). To identify molecular fingerprints associated with disease, circulating exosomes derived from healthy control (HC) individuals were compared against schizophrenia (SCZ) patients and late-onset Alzheimer’s disease (LOAD) patients. A significant epitope pattern was identified for LOAD (CD1c and CD2) but not for SCZ compared to HC. Thus, analysis of cell type- and disease-specific exosome signatures of iPSC-derived cell cultures may provide a valuable model system to explore proteomic biomarkers for the identification of novel disease profiles.

  • Article
    Open Access
    Tanning bed use in Germany between 2015 and 2022: Representative data of 28,000 individuals on indoor tanning, risk awareness and reasons for use
    (2023-12-19) Diehl, Katharina; Breitbart, Eckhard W.; de Buhr, Yvonne; Görig, Tatiana
    Background

    Tanning beds were classified as first‐group carcinogens in 2009. Nonetheless, research shows that people in industrialized Western countries use tanning beds. Based on the National Cancer Aid Monitoring (NCAM) including representative data on 28,000 individuals from Germany, we quantified the prevalence as a trend from 2015 to 2022, identified determinants of tanning bed use and analysed risk awareness and reasons for use.

    Methods

    We used NCAM data from 2015 to 2022 to analyse the trends in the prevalence of tanning bed use (n = 28,000). To determine the characteristics of tanning bed users, risk awareness and reasons, we combined data from the waves 2019 to 2022 (n = 16,000, 49.2% female, 16–65 years) in a pooled dataset to have sufficient power to detect even smaller associations.

    Results

    Tanning bed use decreased to 5.1% in 2022. The use of tanning beds in spas, fitness and beauty facilities increased, except during the COVID‐19 pandemic, while the use in tanning salons decreased. Typical tanning bed users were female, middle‐aged, occupied, higher educated, had an immigrant background and were former or current smokers. Risk awareness was the lowest among the current users. The most frequently mentioned reasons were relaxation, enhancement of attractiveness and pre‐tanning.

    Discussion

    Our nationwide representative data showed that the prevalence of indoor tanning has decreased. Of concern are the lower risk awareness among current users and the shift in place of use towards facilities associated with health and wellness. To further reduce the use of tanning beds, targeted information, educational campaigns and extended legislation are considered helpful.

  • Article
    Open Access
    Molecular Rhodium Complex within N‐Rich Porous Polymer Macroligand as Heterogeneous Catalyst for the Visible‐Light Driven CO2 Photoreduction
    (2023-11-29) Newar, Rajashree; Ghosh, Ashta C.; KUMARI RIDDHI, Riddhi; Rajapaksha, Rémy; Samanta, Partha; Wisser, Florian M.; Canivet, Jérôme

    The heterogenization of molecular catalysts within a porous solid acting as macroligand can advantageously open access to enhanced stability and productivity, and thus to more sustainable catalytic process. Herein, a porous organic polymer (POP) made through metal‐free polymerization using bipyridine repeating units is reported. This N‐rich POP is an efficient macroligand for the heterogenization of molecular rhodium complexes. The intrinsic catalytic activity of the heterogenized catalyst is slightly higher than that of its homogeneous molecular counterpart for formic acid production as a unique carbon‐containing product. The heterogenization of the rhodium catalysts enables recycling for a total productivity of up to 8.3 g of formic acid per gram of catalyst after 7 reuses using visible light as the sole energy source.

  • Article
    Open Access
    Coupling scales in process‐based soil organic carbon modeling including dynamic aggregation
    (2024-01-18) Zech, Simon; Prechtel, Alexander; Ray, Nadja
    Background

    Carbon storage and turnover in soils depend on the interplay of soil architecture, microbial activities, and soil organic matter (SOM) dynamics. For a fundamental understanding of the mechanisms that drive these processes, not only the exploitation of advanced experimental techniques down to the nanoscale is necessary but also spatially explicit and dynamic image‐based modeling at the pore scale.

    Aim

    We present a modeling approach that is capable of transferring microscale information into macroscale simulations at the profile scale. This enables the prediction of future developments of carbon fluxes and the impact of changes in the environmental conditions linking scales.

    Method

    We consider a mathematical model for CO2 transport across soil profiles (macroscale), which is informed by a pore‐scale (microscale) model for C turnover. It allows for the dynamic, self‐organized re‐arrangement of solid building units, aggregates and particulate organic matter (POM) based on surface interactions, realized by a cellular automaton method, and explicitly takes spatial effects on POM turnover such as occlusion into account. We further include the macroscopic environmental conditions water saturation, POM content, and oxygen concentration.

    Results

    The coupled simulations of macroscopic transport and pore‐scale carbon and aggregate turnover reveal the complex, nonlinear interplay of the underlying processes. Limitations by diffusive transport, oxygen availability, texture‐dependent occlusion and turnover of OM drive CO2 production and carbon storage.

    Conclusions

    This emphasizes the need for such micro–macro models exchanging information on different scales to investigate and quantify the effects of structural changes, variations in environmental conditions, or degradation processes on carbon turnover.

  • Article
    Open Access
    Toward accurate and fast velocity quantification with 3D ultrashort TE phase‐contrast imaging
    (2024-01-04) Degenhardt, Katja; Schmidt, Simon; Aigner, Christoph S.; Kratzer, Fabian J.; Seiter, Daniel P.; Mueller, Max; Kolbitsch, Christoph; Nagel, Armin M.; Wieben, Oliver; Schaeffter, Tobias; Schulz‐Menger, Jeanette; Schmitter, Sebastian
    Purpose

    Traditional phase‐contrast MRI is affected by displacement artifacts caused by non‐synchronized spatial‐ and velocity‐encoding time points. The resulting inaccurate velocity maps can affect the accuracy of derived hemodynamic parameters. This study proposes and characterizes a 3D radial phase‐contrast UTE (PC‐UTE) sequence to reduce displacement artifacts. Furthermore, it investigates the displacement of a standard Cartesian flow sequence by utilizing a displacement‐free synchronized‐single‐point‐imaging MR sequence (SYNC‐SPI) that requires clinically prohibitively long acquisition times.

    Methods

    3D flow data was acquired at 3T at three different constant flow rates and varying spatial resolutions in a stenotic aorta phantom using the proposed PC‐UTE, a Cartesian flow sequence, and a SYNC‐SPI sequence as reference. Expected displacement artifacts were calculated from gradient timing waveforms and compared to displacement values measured in the in vitro flow experiments.

    Results

    The PC‐UTE sequence reduces displacement and intravoxel dephasing, leading to decreased geometric distortions and signal cancellations in magnitude images, and more spatially accurate velocity quantification compared to the Cartesian flow acquisitions; errors increase with velocity and higher spatial resolution.

    Conclusion

    PC‐UTE MRI can measure velocity vector fields with greater accuracy than Cartesian acquisitions (although pulsatile fields were not studied) and shorter scan times than SYNC‐SPI. As such, this approach is superior to traditional Cartesian 3D and 4D flow MRI when spatial misrepresentations cannot be tolerated, for example, when computational fluid dynamics simulations are compared to or combined with in vitro or in vivo measurements, or regional parameters such as wall shear stress are of interest.

  • Article
    Open Access
    Uncomfortable staring? Gaze to other people in social situations is inhibited in both infants and adults
    (2023-12-22) Kulke, Louisa; Ertugrul, Sahura; Reyentanz, Emely; Thomas, Vanessa

    People attract infants’ and adults’ gaze when presented on a computer screen. However, in live social situations, adults inhibit their gaze at strangers to avoid sending inappropriate social signals. Such inhibition of gaze has never been directly investigated in infants. The current preregistered study measured gaze and neural responses (EEG alpha power) to a confederate in a live social situation compared to a video of this confederate. Adults looked less at the live confederate than at the video of the confederate, although their neural responses suggest that they were overall equally attentive in both situations. Infants also looked less at the live confederate than at the video of the confederate, with similar neural response patterns. The gaze difference between live social and video situations increased with age. The study shows that young infants are already sensitive to social context and show decreased gaze to strangers in social situations.

    Research Highlights

    This study shows that infants and adults look more at a video of a stranger than at a stranger that is present live in a social situation.

    Neural responses suggest that adults are equally attentive in both live and video situations but inhibit their gaze at the stranger in live social situations.

    Infants show a similar pattern of shorter gaze at a stranger who is present in person than at a video of this stranger.

    The study shows that gaze in infants and adults may diverge from cognitive processes measured through EEG, highlighting the importance of combining behavioural and neural measures in natural interactions.

  • Article
    Open Access
    Peripheral Upregulation of Parkinson’s Disease-Associated Genes Encoding α-Synuclein, β-Glucocerebrosidase, and Ceramide Glucosyltransferase in Major Depression
    (MDPI, 2024-03-12) Brazdis, Razvan-Marius; von Zimmermann, Claudia; Lenz, Bernd; Kornhuber, Johannes; Mühle, Christiane

    Due to the high comorbidity of Parkinson’s disease (PD) with major depressive disorder (MDD) and the involvement of sphingolipids in both conditions, we investigated the peripheral expression levels of three primarily PD-associated genes: α-synuclein (SNCA), lysosomal enzyme β-glucocerebrosidase (GBA1), and UDP-glucose ceramide glucosyltransferase (UGCG) in a sex-balanced MDD cohort. Normalized gene expression was determined by quantitative PCR in patients suffering from MDD (unmedicated n = 63, medicated n = 66) and controls (remitted MDD n = 39, healthy subjects n = 61). We observed that expression levels of SNCA (p = 0.036), GBA1 (p = 0.014), and UGCG (p = 0.0002) were higher in currently depressed patients compared to controls and remitted patients, and expression of GBA1 and UGCG decreased in medicated patients during three weeks of therapy. Additionally, in subgroups, expression was positively correlated with the severity of depression and anxiety. Furthermore, we identified correlations between the gene expression levels and PD-related laboratory parameters. Our findings suggest that SNCA, GBA1, and UGCG analysis could be instrumental in the search for biomarkers of MDD and in understanding the overlapping pathological mechanisms underlying neuro-psychiatric diseases.

  • Article
    Open Access
    Reinforcing Tissue‐Engineered Cartilage: Nanofibrillated Cellulose Enhances Mechanical Properties of Alginate Dialdehyde–Gelatin Hydrogel
    (2023-09-15) chayanun, slila; Soufivand, Anahita Ahmadi; Faber, Jessica; Budday, Silvia; Lohwongwatana, Boonrat; Boccaccini, Aldo R.

    Cartilage tissue engineering offers a promising option for treating osteochondral defects. Alginate dialdehyde–gelatin (ADA–GEL) hydrogel has been explored as promising material for soft tissue scaffolds; however, its low stiffness has posed a constraint to load bearing applications. Herein, this limitation is addressed by introducing nanofibrillated cellulose (NFC) into the ADA–GEL matrix. The effect of NFC on the physicochemical properties of hydrogels is evaluated. Fourier transform infrared spectra demonstrate no chemical interaction between NFC and ADA–GEL, while scanning electron microscopy pictures reveal NFC fibers embedded in the hydrogel matrix, thus confirming the fiber‐reinforced composite hypothesis. NFC‐reinforced ADA–GEL (AG‐N) composite hydrogels exhibit increased stiffness, with a maximum compressive effective modulus of 19.6 ± 3.0 kPa at 25% w/w NFC content. ATDC5 cell viability and proliferation as well as chondrogenic differentiation are assessed using immunohistochemical staining for sulfated glycosaminoglycans and collagen type II. A possible application of AG‐N hydrogels as an osteochondral plug is also proposed, with polyetheretherketone as the subchondral bone anchor part. The mechanical properties of the resulting osteochondral device highlight its potential as a promising biomaterial for treatment of osteochondral defects. These findings provide valuable insights into the development of AG‐N hydrogels for load‐bearing tissue engineering applications.