Changes in Liver Mechanical Properties and Water Diffusivity During Normal Pregnancy Are Driven by Cellular Hypertrophy

During pregnancy, the body's hyperestrogenic state alters hepatic metabolism and synthesis. While biochemical changes related to liver function during normal pregnancy are well understood, pregnancy-associated alterations in biophysical properties of the liver remain elusive. In this study, we investigated 26 ex vivo fresh liver specimens harvested from pregnant and non-pregnant rats by diffusion-weighted imaging (DWI) and magnetic resonance elastography (MRE) in a 0.5-Tesla compact magnetic resonance imaging (MRI) scanner. Water diffusivity and viscoelastic parameters were compared with histological data and blood markers. We found livers from pregnant rats to have (i) significantly enlarged hepatocytes (26 ± 15%, p < 0.001), (ii) increased liver stiffness (12 ± 15%, p = 0.012), (iii) decreased viscosity (-23 ± 14%, p < 0.001), and (iv) increased water diffusivity (12 ± 11%, p < 0.001). In conclusion, increased stiffness and reduced viscosity of the liver during pregnancy are mainly attributable to hepatocyte enlargement. Hypertrophy of liver cells imposes fewer restrictions on intracellular water mobility, resulting in a higher hepatic water diffusion coefficient. Collectively, MRE and DWI have the potential to inform on structural liver changes associated with pregnancy in a clinical context

Adipose cells and tissues soften with lipid accumulation while in diabetes adipose tissue stiffens

Adipose tissue expansion involves both differentiation of new precursors and size increase of mature adipocytes. While the two processes are well balanced in healthy tissues, obesity and diabetes type II are associated with abnormally enlarged adipocytes and excess lipid accumulation. Previous studies suggested a link between cell stiffness, volume and stem cell differentiation, although in the context of preadipocytes, there have been contradictory results regarding stiffness changes with differentiation. Thus, we set out to quantitatively monitor adipocyte shape and size changes with differentiation and lipid accumulation. We quantified by optical diffraction tomography that differentiating preadipocytes increased their volumes drastically. Atomic force microscopy (AFM)-indentation and -microrheology revealed that during the early phase of differentiation, human preadipocytes became more compliant and more fluid-like, concomitant with ROCK-mediated F-actin remodelling. Adipocytes that had accumulated large lipid droplets were more compliant, and further promoting lipid accumulation led to an even more compliant phenotype. In line with that, high fat diet-induced obesity was associated with more compliant adipose tissue compared to lean animals, both for drosophila fat bodies and murine gonadal adipose tissue. In contrast, adipose tissue of diabetic mice became significantly stiffer as shown not only by AFM but also magnetic resonance elastography. Altogether, we dissect relative contributions of the cytoskeleton and lipid droplets to cell and tissue mechanical changes across different functional states, such as differentiation, nutritional state and disease. Our work therefore sets the basis for future explorations on how tissue mechanical changes influence the behaviour of mechanosensitive tissue-resident cells in metabolic disorders

Potential of Airborne LiDAR Derived Vegetation Structure for the Prediction of Animal Species Richness at Mount Kilimanjaro

The monitoring of species and functional diversity is of increasing relevance for the development of strategies for the conservation and management of biodiversity. Therefore, reliable estimates of the performance of monitoring techniques across taxa become important. Using a unique dataset, this study investigates the potential of airborne LiDAR-derived variables characterizing vegetation structure as predictors for animal species richness at the southern slopes of Mount Kilimanjaro. To disentangle the structural LiDAR information from co-factors related to elevational vegetation zones, LiDAR-based models were compared to the predictive power of elevation models. 17 taxa and 4 feeding guilds were modeled and the standardized study design allowed for a comparison across the assemblages. Results show that most taxa (14) and feeding guilds (3) can be predicted best by elevation with normalized RMSE values but only for three of those taxa and two of those feeding guilds the difference to other models is significant. Generally, modeling performances between different models vary only slightly for each assemblage. For the remaining, structural information at most showed little additional contribution to the performance. In summary, LiDAR observations can be used for animal species prediction. However, the effort and cost of aerial surveys are not always in proportion with the prediction quality, especially when the species distribution follows zonal patterns, and elevation information yields similar results

Die Sprache des Artakserksovo dejstvo

Die Arbeit besteht somit aus zwei Hauptteilen. Zunächst werden in den "Vorbemerkungen" die wichtigsten Begriffe gegeneinander abgegrenzt und ein Forschungsüberblick gegeben. Da die Entwicklung der russischen Sprache eng mit den jeweiligen geschichtlichen Ereignissen verknüpft ist, werden im ersten, mehr referierenden Teil die geschichtlichen Voraussetzungen für den Sprachwandel in einem kurzen Überblick dargelegt. Anschließend wird die sprachliche Umbruchsituation charakterisiert. Einen eigenen Abschnitt wird dabei die Einordnung des "Artakserksovo dejstvo" in den literarischen Kontext seiner Zeit bilden. Im zweiten Teil wird der Text des "Artakserksovo dejstvo" sprachlich untersucht

Die Sprache des Artakserksovo dejstvo

Die Arbeit besteht somit aus zwei Hauptteilen. Zunächst werden in den "Vorbemerkungen" die wichtigsten Begriffe gegeneinander abgegrenzt und ein Forschungsüberblick gegeben. Da die Entwicklung der russischen Sprache eng mit den jeweiligen geschichtlichen Ereignissen verknüpft ist, werden im ersten, mehr referierenden Teil die geschichtlichen Voraussetzungen für den Sprachwandel in einem kurzen Überblick dargelegt. Anschließend wird die sprachliche Umbruchsituation charakterisiert. Einen eigenen Abschnitt wird dabei die Einordnung des "Artakserksovo dejstvo" in den literarischen Kontext seiner Zeit bilden. Im zweiten Teil wird der Text des "Artakserksovo dejstvo" sprachlich untersucht

Elektronik

Mikro- und nanoelektronische Schaltungen und Systeme fallen aufgrund der Gesamtabmessungen der Chips zwar zunächst nicht als Nanotechnologie ins Auge - Chips bestehen aber aus bis zu einigen Milliarden einzelner miteinander integrierter Bauelemente, die mittlerweile Abmessungen von bis unter 30 nm haben, bei Schichtdicken bis hinunter zu einem Nanometer. Die Herstellung, Funktionalität und Zuverlässigkeit mikro- und nanoelektronischer Systeme hängt von einer Vielzahl von Nanoeffekten ab. Insgesamt ist die Mikro- und Nanoelektronik für viele industrielle Branchen in Deutschland und Europa eine Schlüsselindustrie. Wegen der technologischen Komplexität erfordert die Forschung auf diesem Gebiet breite Kooperationen zwischen Industrie, Instituten und Universitäten. Fraunhofer-Institute wie das IISB und das ENAS tragen wesentlich zur Forschung und Anwendung in diesem Gebiet bei

Functional superhydrophobic surfaces made of Janus micropillars

We demonstrate the fabrication of superhydrophobic surfaces consisting of micropillars with hydrophobic sidewalls and hydrophilic tops, referred to as Janus micropillars. Therefore we first coat a micropillar array with a mono- or bilayer of polymeric particles, and merge the particles together to shield the top faces while hydrophobizing the walls. After removing the polymer film, the top faces of the micropillar arrays can be selectively chemically functionalised with hydrophilic groups. The Janus arrays remain superhydrophobic even after functionalisation as verified by laser scanning confocal microscopy. The robustness of the superhydrophobic behaviour proves that the stability of the entrapped air cushion is determined by the forces acting at the rim of the micropillars. This insight should stimulate a new way of designing super liquid-repellent surfaces with tunable liquid adhesion. In particular, combining superhydrophobicity with the functionalisation of the top faces of the protrusions with hydrophilic groups may have exciting new applications, including high-density microarrays for high-throughput screening of bioactive molecules, cells, or enzymes or efficient water condensation. However, so far chemical attachment of hydrophilic molecules has been accompanied with complete wetting of the surface underneath. The fabrication of superhydrophobic surfaces where the top faces of the protrusions can be selectively chemically post-functionalised with hydrophilic molecules, while retaining their superhydrophobic properties, is both promising and challenging