The Mona Lisa Illusion—scientists see her looking at them though she isn’t

Horstmann G, Loth S. The Mona Lisa Illusion—scientists see her looking at them though she isn’t. i-Perception. 2019;10(1): 2041669518821702.If the person depicted in an image gazes at the camera or painter, a viewer perceives this as being gazed at. The viewers’ perception holds irrespectively of their position relative to image. This is the Mona Lisa effect named after the subject of Leonardo’s famous painting La Gioconda. The effect occurs reliably but was not tested with Mona Lisa herself. Remarkably, viewers judged Mona Lisa’s gaze as directed to their right-hand side irrespectively of the image zoom, its horizontal position on screen, and the distance of the ruler that was used for measuring the gaze direction

Expression and processing of Plasmodium berghei SERA3 during liver stages

Cysteine proteases mediate liberation of Plasmodium berghei merozoites from infected hepatocytes. In an attempt to identify the responsible parasite proteases, we screened the genome of P. berghei for cysteine protease-encoding genes. RT-PCR analyses revealed that transcription of four out of five P. berghei serine repeat antigen (PbSERA) genes was strongly upregulated in late liver stages briefly before the parasitophorous vacuole membrane ruptured to release merozoites into the host cell cytoplasm, suggesting a role of PbSERA proteases in these processes. In order to characterize PbSERA3 processing, we raised an antiserum against a non-conserved region of the protein and generated a transgenic P. berghei strain expressing a TAP-tagged PbSERA3 under the control of the endogenous promoter. Immunofluorescence assays revealed that PbSERA3 leaks into the host cell cytoplasm during merozoite development, where it might contribute to host cell death or activate host cell proteases that execute cell death. Importantly, processed PbSERA3 has been detected by Western blot analysis in cell extracts of schizont-infected cells and merozoite-infected detached hepatic cells

Identification and Characterization of a Liver Stage-Specific Promoter Region of the Malaria Parasite Plasmodium

During the blood meal of a Plasmodium-infected mosquito, 10 to 100 parasites are inoculated into the skin and a proportion of these migrate via the bloodstream to the liver where they infect hepatocytes. The Plasmodium liver stage, despite its clinical silence, represents a highly promising target for antimalarial drug and vaccine approaches. Successfully invaded parasites undergo a massive proliferation in hepatocytes, producing thousands of merozoites that are transported into a blood vessel to infect red blood cells. To successfully develop from the liver stage into infective merozoites, a tight regulation of gene expression is needed. Although this is a very interesting aspect in the biology of Plasmodium, little is known about gene regulation in Plasmodium parasites in general and in the liver stage in particular. We have functionally analyzed a novel promoter region of the rodent parasite Plasmodium berghei that is exclusively active during the liver stage of the parasite. To prove stage-specific activity of the promoter, GFP and luciferase reporter assays have been successfully established, allowing both qualitative and accurate quantitative analysis. To further characterize the promoter region, the transcription start site was mapped by rapid amplification of cDNA ends (5′-RACE). Using promoter truncation experiments and site-directed mutagenesis within potential transcription factor binding sites, we suggest that the minimal promoter contains more than one binding site for the recently identified parasite-specific ApiAP2 transcription factors. The identification of a liver stage-specific promoter in P. berghei confirms that the parasite is able to tightly regulate gene expression during its life cycle. The identified promoter region might now be used to study the biology of the Plasmodium liver stage, which has thus far proven problematic on a molecular level. Stage-specific expression of dominant-negative mutant proteins and overexpression of proteins normally active in other life cycle stages will help to understand the function of the proteins investigated

Automatisiertes Off-Line-Rüsten von Ummantelungsanlagen

Ummanteln ist eine Fertigungstechnologie, deren Bedeutung noch immer w~chst. Mit ihr werden Holzwerkstoffprofile und Kaschierungen mit Schmelzklebstoffen gefügt Zu deutlich geringeren Kosten werden Profjlelemente erzeugt, die heute ihren Vorbildern aus Massivholz oder Metallen in Optik und Haptik gleichkommen oder einen eigenständigen Charme aufweisen. Allerdings müssen beim Ummantelungsprozess eine Vielzahl an Andruckrollen und ggf. Heißluftdüsen entlang des durchlaufenden Profils angeordnet werden, um die meist nur eingeschränkt formbare, mit heißem Schmelzkleber beschichtete Kaschierung mit dem Profilkern zu fügen. Da die Maschinen im Stillstand manuell gerüstet werden, reduziert die dafür benötigte Rüstzeit deutlich die Produktivität der Ummantelungsanlagen. Daher muss das Rüsten off-line, parallel zu den Fertigungsaufträgen. an einem separaten ROststand erfolgen und sich somit die Belegungszeit der Anlage auf das Einwechseln der Rollensätze beschränken. Basierend auf einer umfangreichen Prozessbetrachtung wurde ein Prozessmodell entwickelt, welches mittels Geometriedaten, Rüstregeln sowie Informationen über Material, Werkzeug und Ummantelungsmaschine ein virtuelles Bild der Rollenpositionierung erzeugt Die daraus gewonnenen Positionen und Anstellwinkel der einzelnen Rollen werden dann Ober einen Postprozessor an einen roboterunterstutzten Rüstplatz weitergegeben, welcher die benötigten Rollenhalter automatisiert rüstet

Scan, extract, wrap, compute:a 3D method to analyse morphological shape differences

Quantitative analysis of shape and form is critical in many biological disciplines, as context-dependent morphotypes reflect changes in gene expression and physiology, e.g., in comparisons of environment-dependent phenotypes, forward/reverse genetic assays or shape development during ontogenesis. 3D-shape rendering methods produce models with arbitrarily numbered, and therefore non-comparable, mesh points. However, this prevents direct comparisons. We introduce a workflow that allows the generation of comparable 3D models based on several specimens. Translocations between points of modelled morphotypes are plotted as heat maps and statistically tested. With this workflow, we are able to detect, model and investigate the significance of shape and form alterations in all spatial dimensions, demonstrated with different morphotypes of the pond-dwelling microcrustacean Daphnia. Furthermore, it allows the detection even of inconspicuous morphological features that can be exported to programs for subsequent analysis, e.g., streamline- or finite-element analysis

Facing the Green Threat: A Water Flea’s Defenses against a Carnivorous Plant

Every ecosystem shows multiple levels of species interactions, which are often difficult to isolate and to classify regarding their specific nature. For most of the observed interactions, it comes down to either competition or consumption. The modes of consumption are various and defined by the nature of the consumed organism, e.g., carnivory, herbivory, as well as the extent of the consumption, e.g., grazing, parasitism. While the majority of consumers are animals, carnivorous plants can also pose a threat to arthropods. Water fleas of the family Daphniidae are keystone species in many lentic ecosystems. As most abundant filter feeders, they link the primary production to higher trophic levels. As a response to the high predatory pressures, water fleas have evolved various inducible defenses against animal predators. Here we show the first example, to our knowledge, in Ceriodaphnia dubia of such inducible defenses of an animal against a coexisting plant predator, i.e., the carnivorous bladderwort (Utricularia x neglecta Lehm, Lentibulariaceae). When the bladderwort is present, C. dubia shows changes in morphology, life history and behavior. While the morphological and behavioral adaptations improve C. dubia’s survival rate in the presence of this predator, the life-history parameters likely reflect trade-offs for the defense

Survey of the Current Activities in the Field of Modeling the Space Debris Environment at TU Braunschweig

The Institute of Space Systems at Technische Universität Braunschweig has long-term experience in the field of space debris modeling. This article reviews the current state of ongoing research in this area. Extensive activities are currently underway to update the European space debris model MASTER. In addition to updating the historical population, the future evolution of the space debris environment is also being investigated. The competencies developed within these activities are used to address current problems with regard to the possibility of an increasing number of catastrophic collisions. Related research areas include, for example, research in the field of orbit determination and the simulation of sensor systems for the acquisition and cataloging of orbital objects. In particular, the ability to provide simulated measurement data for object populations in almost all size ranges is an important prerequisite for these investigations. Some selected results on the distribution of space debris on Earth orbit are presented in terms of spatial density. Furthermore, specific fragmentation events will be discussed

Spatial variation of fine particulate matter levels in Nairobi before and during the COVID-19 curfew: implications for environmental justice

Abstract: The temporary decrease of fine particulate matter (PM2.5) concentrations in many parts of the world due to the COVID-19 lockdown spurred discussions on urban air pollution and health. However there has been little focus on sub-Saharan Africa, as few African cities have air quality monitors and if they do, these data are often not publicly available. Spatial differentials of changes in PM2.5 concentrations as a result of COVID also remain largely unstudied. To address this gap, we use a serendipitous mobile air quality monitoring deployment of eight Sensirion SPS 30 sensors on motorbikes in the city of Nairobi starting on 16 March 2020, before a COVID-19 curfew was imposed on 25 March and continuing until 5 May 2020. We developed a random-forest model to estimate PM2.5 surfaces for the entire city of Nairobi before and during the COVID-19 curfew. The highest PM2.5 concentrations during both periods were observed in the poor neighborhoods of Kariobangi, Mathare, Umoja, and Dandora, located to the east of the city center. Changes in PM2.5 were heterogeneous over space. PM2.5 concentrations increased during the curfew in rapidly urbanizing, the lower-middle-class neighborhoods of Kahawa, Kasarani, and Ruaraka, likely because residents switched from LPG to biomass fuels due to loss of income. Our results indicate that COVID-19 and policies to address it may have exacerbated existing air pollution inequalities in the city of Nairobi. The quantitative results are preliminary, due to sampling limitations and measurement uncertainties, as the available data came exclusively from low-cost sensors. This research serves to highlight that spatial data that is essential for understanding structural inequalities reflected in uneven air pollution burdens and differential impacts of events like the COVID pandemic. With the help of carefully deployed low-cost sensors with improved spatial sampling and at least one reference-quality monitor for calibration, we can collect data that is critical for developing targeted interventions that address environmental injustice in the African context

Impact of Cerebral Microbleeds in Stroke Patients with Atrial Fibrillation

OBJECTIVES: Cerebral microbleeds are associated with the risks of ischemic stroke and intracranial hemorrhage, causing clinical dilemmas for antithrombotic treatment decisions. We aimed to evaluate the risks of intracranial hemorrhage and ischemic stroke associated with microbleeds in patients with atrial fibrillation treated with Vitamin K antagonists, direct oral anticoagulants, antiplatelets, and combination therapy (i.e. concurrent oral anticoagulant and antiplatelet) METHODS: We included patients with documented atrial fibrillation from the pooled individual patient data analysis by the Microbleeds International Collaborative Network. Risks of subsequent intracranial hemorrhage and ischemic stroke were compared between patients with and without microbleeds, stratified by antithrombotic use. RESULTS: A total of 7,839 patients were included. The presence of microbleeds was associated with an increased relative risk of intracranial hemorrhage (aHR 2.74, 95% confidence interval 1.76 - 4.26) and ischemic stroke (aHR 1.29, 95% confidence interval 1.04 - 1.59). For the entire cohort, the absolute incidence of ischemic stroke was higher than intracranial hemorrhage regardless of microbleeds burden. However, for the subgroup of patients taking combination of anticoagulant and antiplatelet therapy, the absolute risk of intracranial hemorrhage exceeded that of ischemic stroke in those with 2-4 microbleeds (25 vs 12 per 1,000 patient-years) and ≥11 microbleeds (94 vs 48 per 1,000 patient-years). INTERPRETATION: Patients with atrial fibrillation and high burden of microbleeds receiving combination therapy have a tendency of higher rate of intracranial hemorrhage than ischemic stroke, with potential for net harm. Further studies are needed to help optimize stroke preventive strategies in this high-risk group. This article is protected by copyright. All rights reserved

Capacitive Touchscreen Sensors for the Measurement of Ions in Electrolytes

This work proposes and explores the use of mutual capacitive touchscreens as sensing tools for ion concentrations in an electrolyte, measuring directly from drops placed on the screen surface. This is explored using a standard, commercially available touchscreen made up of a conductive indium tin oxide on glass, coated with a parylene C layer. Simulations using COMSOL Multiphysics show that sample polarisation close to the surface dominates the sensor capacitance. The model quantifies the signal change for samples placed off the touchscreen electrodes and experiments confirm an optimal drop volume of 200 µL for measurements with the touchscreen prototype. Thin polymer coatings turn out essential for measuring electrolytes via the projected mutual capacitance. The touchscreen senses a tight semi-log correlation of its capacitance with the conductivity of electrolytes below 100 μS/cm. This correlation is dependent on anion concentration and nearly independent of the measured cations for a positive electrode. Furthermore, a new approach is developed to fabricate simplified, affordable touchscreen-inspired ITO sensors using standard laser-cutter equipment. The fabricated devices show more than double the sensitivity for measuring aqueous samples compared to the commercial touchscreen. Interdigital comb structures increase the sensitivity further from 4.0 to 8.8 compared to a simple line structure. Simulations help guide the design of sensing structures concerning sensitivity and spatial robustness. Finally, the challenge of selectivity is addressed through ion-selective membranes. Initial results on the formulation and fabrication of polymeric membranes show a deterioration of the sensitivity to 1.3 for poly(n-butyl) acrylate and 2.4 for poly vinyl chloride. While reproducible polymer membranes can successfully be fabricated on an ITO glass sensor, the research identifies a need for additional work on ion-selective films. This work demonstrates that liquid measurements on a touchscreen do not require direct contact between the sample and the electrodes for conductivity determination. In the future, polymer layers may prevent electrode degradation and have the potential to be translated in the future towards use with existing mobile technologies. A sub-micromolar detection limit for ions and a linear detection window until 500 µM is shown. The presented devices are suitable for trace metal contaminant detection in drinking water and the presence of soil nutrients such as phosphate, nitrate, phosphate, and potassium.This research was supported by the UK Engineering and Physical Sciences Research Council (EPSRC) grant EP/L015889/1 for the EPSRC Centre for Doctoral Training in Sensor Technologies and Applications