Anomalous size-dependence of interfacial profiles between coexisting phases of polymer mixtures in thin film geometry: A Monte-Carlo simulation

The interfacial profile between coexisting phases of a binary mixture (A,B) in a thin film of thickness D and lateral linear dimensions L depends sensitively on both linear dimensions and on the nature of boundary conditions and statistical ensembles applied. These phenomena generic for systems in confined geometry are demonstrated by Monte-Carlo simulations of the bond fluctuation model of symmetric polymer mixtures. Both the canonical and semi-grand-canonical ensemble are studied. In the canonical ensemble, the interfacial width w increases (from small values which are of the same order as the intrinsic profile) like sqrt{D}, before a crossover to a saturation value w_max (w_max^2 proportional to ln L) sets in. In the semi-grand-canonical ensemble, however, one finds the same widths (w proportional to sqrt{D}) as in the canonical ensemble for not too large L, while for large L the interfacial profile is smeared out over a finite fraction of the film thickness (w proportional to D for D -> infinity). We discuss the implications of these findings for the interpretation of both simulations and experiments.Comment: 42 pages, including 15 PS figures, to appear in JC

Tolerance without clonal expansion: Self-antigen-expressing B cells program self-reactive T cells for future deletion

B cells have been shown in various animal models to induce immunological tolerance leading to reduced immune responses and protection from autoimmunity. We show that interaction of B cells with naive T cells results in T cell triggering accompanied by the expression of negative costimulatory molecules such as PD-1, CTLA-4, B and T lymphocyte attenuator, and CD5. Following interaction with B cells, T cells were not induced to proliferate, in a process that was dependent on their expression of PD-1 and CTLA-4, but not CD5. In contrast, the T cells became sensitive to Ag-induced cell death. Our results demonstrate that B cells participate in the homeostasis of the immune system by ablation of conventional self-reactive T cells

Migration, Integration, Asyl in Deutschland 2020: Politische und Rechtliche Entwicklungen

Der jährlich erscheinende Politikbericht der nationalen Kontaktstelle des Europäischen Migrationsnetzwerks (EMN) beschreibt relevante Entwicklungen der Migrations-, Integration- und Asylpolitik im Jahr 2020. Der 17. Politikbericht im Rahmen des EMN bietet wie gewohnt einen Überblick über die wichtigsten politischen, rechtlichen und institutionellen Entwicklungen des Jahres 2020 in den folgenden Bereichen: Allgemeine politische, rechtliche und institutionelle Struktur, legale Zuwanderung und Mobilität, internationaler Schutz und Asyl, unbegleitete Minderjährige und andere besonders schutzbedürftige Personengruppen, Integration und gesellschaftlicher Zusammenhalt, Staatsangehörigkeit und Staatenlosigkeit, Grenzkontrolle und Visumpolitik, irreguläre Migration und Schleusung, Rückkehr, Menschenhandel und Migration und Entwicklung.The annual policy report of the National Contact Point of the European Migration Network (EMN) describes relevant developments of the year 2020 in migration, integration and asylum policy. As usual, the 17th Policy Report of the EMN provides an overview of the most important political, legal and institutional developments in 2020 in the following areas: general political, legal and institutional structure, legal migration and mobility, international protection and asylum, unaccompanied minors and other vulnerable groups, integration and antidiscrimination, citizenship and statelessness, border control and visa policy, irregular migration and migrant smuggling, returns, trafficking in human beings, and migration and development

Body Fat Estimation from Surface Meshes using Graph Neural Networks

Body fat volume and distribution can be a strong indication for a person's overall health and the risk for developing diseases like type 2 diabetes and cardiovascular diseases. Frequently used measures for fat estimation are the body mass index (BMI), waist circumference, or the waist-hip-ratio. However, those are rather imprecise measures that do not allow for a discrimination between different types of fat or between fat and muscle tissue. The estimation of visceral (VAT) and abdominal subcutaneous (ASAT) adipose tissue volume has shown to be a more accurate measure for named risk factors. In this work, we show that triangulated body surface meshes can be used to accurately predict VAT and ASAT volumes using graph neural networks. Our methods achieve high performance while reducing training time and required resources compared to state-of-the-art convolutional neural networks in this area. We furthermore envision this method to be applicable to cheaper and easily accessible medical surface scans instead of expensive medical images

Explainable 2D Vision Models for 3D Medical Data

Training Artificial Intelligence (AI) models on three-dimensional image data presents unique challenges compared to the two-dimensional case: Firstly, the computational resources are significantly higher, and secondly, the availability of large pretraining datasets is often limited, impeding training success. In this study, we propose a simple approach of adapting 2D networks with an intermediate feature representation for processing 3D volumes. Our method involves sequentially applying these networks to slices of a 3D volume from all orientations. Subsequently, a feature reduction module combines the extracted slice features into a single representation, which is then used for classification. We evaluate our approach on medical classification benchmarks and a real-world clinical dataset, demonstrating comparable results to existing methods. Furthermore, by employing attention pooling as a feature reduction module we obtain weighted importance values for each slice during the forward pass. We show that slices deemed important by our approach allow the inspection of the basis of a model's prediction

Healthcare Utilization and Costs in Sepsis Survivors in Germany-Secondary Analysis of a Prospective Cohort Study

Background: Survivors of sepsis often face long-term sequelae after intensive care treatment. Compared to the period of hospitalization, little is known about the ambulatory healthcare utilization in sepsis patients. The study evaluated healthcare utilization and associated costs of sepsis care including allied health professions after initial hospitalization. Methods: Secondary analysis was performed on data in 210 sepsis patients prospectively enrolled from nine intensive care study centers across Germany. Data was collected via structured surveys among their Primary care (Family-) physicians (PCPs) within the first month after discharge from ICU (baseline) and again at 6, 12 and 24 months after discharge, each relating to the period following the last survey. Costs were assessed by standardized cost unit rates from a health care system’s perspective. Changes in healthcare utilization and costs over time were calculated using the Wilcoxon rank-sum test. Results: Of the 210 patients enrolled, 146 (69.5%) patients completed the 24 months follow-up. In total, 109 patients were hospitalized within the first 6 months post-intensive care. Mean total direct costs per patient at 0–6 months were €17,531 (median: €6047), at 7–12 months €9029 (median: €3312), and at 13–24 months €18,703 (median: €12,828). The largest contributor to the total direct costs within the first 6 months was re-hospitalizations (€13,787 (median: €2965). After this first half year, we observed a significant decline in inpatient care costs for re-hospitalizations (p ≤ 0.001). PCPs were visited by more than 95% of patients over 24 months. Conclusions: Sepsis survivors have high health care utilization. Hospital readmissions are frequent and costly. Highest costs and hospitalizations were observed in more than half of patients within the first six months post-intensive care. Among all outpatient care providers, PCPs were consulted most frequently. Clinical impact: Sepsis survivors have a high healthcare utilization and related costs which persist after discharge from hospital. Within outpatient care, possible needs of sepsis survivors as physiotherapy or psychotherapy seem not to be met appropriately. Development of sepsis aftercare programs for early detection and treatment of complications should be prioritized

UNDERCOVEREISAGENTEN - ERSTE EXPEDITION UND AKTUELLER STAND DES ARKTISCHEN PERMAFROSTPROJEKTS

Die Menschen in der Arktis sind seit mehreren Jahrzehnten mit Veränderungen ihres Lebensraums, wie dem Auftauen des Permafrosts durch den globalen Klimawandel, konfrontiert. Ziel dieses Projekts ist es, die Erste Expedition und aktueller Stand des arktischen Permafrostprojekts Auswirkungen des Permafrosttauens durch die Erfassung und Analyse von Bildmaterial von UAVs zusammen mit Schüler*innen (SuS) in Kanada und Deutschland zu untersuchen. Während einer Expedition im September 2022 in Nordkanada durch das AWI, DLR und HeiGIT wurden erste UAV-Daten gemeinsam mit SuS der Moose Kerr School in Aklavik aufgenommen. Neben den rund 30000 Einzelfotos über einer Fläche von ca. 13km² wurden die Grundlagen der Datenerhebung sowie die Projektziele der gemeinschaftlichen Permafrost-Untersuchung vermittelt. Vermittelte Ziele sind die selbstständig fortgeführte Datenaufnahme durch interessierte SuS, sowie die selbstständige Formulierung eigener wissenschaftl. Fragestellungen. Es erfolgte plangemäß die Einarbeitung von lokalem Wissen, um weitere Fragestellungen der lokalen Bevölkerung zu adressieren. Die Daten werden aktuell aufbereitet, um über eine Crowdmapping-Anwendung zur Verfügung gestellt zu werden

Tree Stem Detection and Crown Delineation in a Structurally Diverse Deciduous Forest Combining Leaf-On and Leaf-Off UAV-SfM Data

Accurate detection and delineation of individual trees and their crowns in dense forest environments are essential for forest management and ecological applications. This study explores the potential of combining leaf-off and leaf-on structure from motion (SfM) data products from unoccupied aerial vehicles (UAVs) equipped with RGB cameras. The main objective was to develop a reliable method for precise tree stem detection and crown delineation in dense deciduous forests, demonstrated at a structurally diverse old-growth forest in the Hainich National Park, Germany. Stem positions were extracted from the leaf-off point cloud by a clustering algorithm. The accuracy of the derived stem co-ordinates and the overall UAV-SfM point cloud were assessed separately, considering different tree types. Extracted tree stems were used as markers for individual tree crown delineation (ITCD) through a region growing algorithm on the leaf-on data. Stem positioning showed high precision values (0.867). Including leaf-off stem positions enhanced the crown delineation, but crown delineations in dense forest canopies remain challenging. Both the number of stems and crowns were underestimated, suggesting that the number of overstory trees in dense forests tends to be higher than commonly estimated in remote sensing approaches. In general, UAV-SfM point clouds prove to be a cost-effective and accurate alternative to LiDAR data for tree stem detection. The combined datasets provide valuable insights into forest structure, enabling a more comprehensive understanding of the canopy, stems, and forest floor, thus facilitating more reliable forest parameter extraction

Semaphorin 6A Improves Functional Recovery in Conjunction with Motor Training after Cerebral Ischemia

Background: We have previously identified Semaphorin 6a (Sema6A) as an upregulated gene product in a gene expression screen in cortical ischemia [1]. Semaphorin 6a was regulated during the recovery phase following ischemia in the cortex. Semaphorin 6a is a member of the superfamily of semaphorins involved in axon guidance and other functions. We hypothesized that the upregulation indicates a crucial role of this molecule in post-stroke rewiring of the brain. Here we have tested this hypothesis by overexpressing semaphorin 6a in the cortex by microinjection of a modified AAV2-virus. A circumscribed cortical infarct was induced, and the recovery of rats monitored for up to 4 weeks using a well-established test battery (accelerated rotarod training paradigm, cylinder test, adhesive tape removal). We observed a significant improvement in post-ischemic recovery of animals injected with the semaphorin 6a virus versus animals treated with a control virus. We conclude that semaphorin 6a overexpressed in the cortex enhances recovery after cerebral ischemia