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Characterization of 3D oxygen concentrations in hydrogels combining astigmatic particle tracking with phosphorescence decay measurements
No full textIn this work, we combine astigmatic particle tracking with phosphorescence decay measurements to determine 3D oxygen concentration distributions in microfluidic systems. Out-of-plane positions are reconstructed to an accuracy of 1.5 μm. The calibrated measurement range covers oxygen concentrations between 0.6 to 27.6 ppm. A method is presented to systematically correct for measurement errors caused by photobleaching taking into account the excitation energy, the cumulative laser irradiation time and the spatially varying intensity profile of the laser. With this method, low measurement errors of less than 2 ppm at ambient oxygen levels can be achieved even after thousands of excitation cycles. To demonstrate the capability of the measurement technique, 3D oxygen concentrations are measured in an agarose hydrogel filled microfluidic chamber across which different pressure and oxygen gradients can be set independently. The results show that oxygen diffusion is superposed by a convective transport of interstitial flow. By matching numerical simulations to the experimental data, further insights into the ratio of convective and diffusive transport are given and a methodology for estimating relevant material parameters is presented. This in situ measurement technique can be applied to improve the design process of supply networks for tissue models.
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Wohnungsbezogene Freiräume als Gesundheitsressource – Anforderungen und Gestaltungsempfehlungen für eine gesundheitsfördernde Freiraumentwicklung. Am Beispiel des genossenschaftlichen Wohnungsbaus
Get PDFDie vorliegende Arbeit mit dem Titel „Wohnungsbezogene Freiräume als Gesundheitsressource –
Anforderungen und Gestaltungsempfehlungen für eine gesundheitsfördernde Freiraumentwicklung. Am Beispiel des genossenschaftlichen Wohnungsbaus“ untersucht, wie Freiräume von Wohnungsbaugenossenschaften gestaltet sein müssen, um eine hohe Aufenthaltsqualität zu bieten. In diesem Zusammenhang wird untersucht, ob die Aufenthaltsqualität eine intensivere Nutzung der wohnungsbezogenen Freiräume fördert und dadurch die positiven Effekte auf die Gesundheit der Bewohner:innen verstärkt.
Vor diesem Hintergrund gliedert sich die Arbeit in drei Hauptteile: Im ersten Teil wird das wissenschaftliche Fundament gelegt, wobei das Forschungsinteresse und die methodischen Ansätze in Form eines Mehrebenen-Methodenmixes dargestellt werden. Zentrale Begriffe wie Stadtnatur, Freiraum, urbane Ökosystemleistungen, Wohlbefinden, Stress, Erholung und Gesundheit werden definiert und im Kontext der Forschungsfragen diskutiert.
Der zweite Teil widmet sich dem konzeptionellen Rahmen und einer vertiefenden theoretischen Auseinandersetzung mit der Rolle urbaner Freiräume für die Gesunderhaltung und Gesundheitsförderung von Stadtbewohner:innen. Unter Einbeziehung theoretischer und empirischer Studien wird nachgewiesen, dass grüngeprägte urbane Freiräume nachweislich positive Effekte auf das Wohlbefinden und die Gesundheit haben. Die vorliegende Arbeit schließt hierbei eine Forschungslücke, da sie sich auf qualitative Faktoren wohnungsnaher Freiräume konzentriert, die bisher in der Forschung weniger Beachtung gefunden haben.
Darüber hinaus wird in der Kontextualisierung das Leben im urbanen Raum thematisiert sowie die Bedeutung von Wohnungsbaugenossenschaften für die Entwicklung und Pflege von Freiräumen hervorgehoben. Es wird deutlich, dass Wohnungsbaugenossenschaften als langfristig agierende Bestandshalter:innen eine zentrale Rolle in der Freiraumentwicklung spielen, da deren Freiräume nicht nur von ästhetischer, sondern auch von sozialer und gesundheitlicher Bedeutung sind. Daher setzt sich die Arbeit u. a. mit den gestalterischen und funktionalen Anforderungen an wohnungsbezogene Freiräume auseinander, wobei die Bedürfnisse der Bewohner:innen und deren Nutzung im Mittelpunkt stehen.
Der dritte Teil dient der anwendungsbezogenen Umsetzung. Hierbei werden 16 Freiräume von sieben Wohnungsbaugenossenschaften mittels des für diese Arbeit entwickelten Methodenmixes analysiert, während die Bewohner:innen von 2.719 Haushalten zu ihrem Nutzungsverhalten und ihren Bedürfnissen befragt worden sind. Die gewonnenen Daten dienen der Entwicklung konkreter Gestaltungs- und Pflegekriterien, die als Leitlinien für die zukunftsfähige Entwicklung wohnungsbezogener Freiräume genutzt werden können. Ein Schwerpunkt liegt auf praktikablen, kostenextensiven Handlungsempfehlungen, die sowohl die Bedürfnisse der Bewohner:innen als auch die klimatischen Herausforderungen, insbesondere im Kontext von Nachverdichtung, energetischer Sanierung und Umgestaltung von Freiräumen berücksichtigen.
Zum Abschluss werden die Handlungsempfehlungen anhand studentischer Entwürfe auf weitere Quartiere übertragen und bewertet. Die Arbeit schließt mit erweiterten Empfehlungen zur strategischen und planerischen Umsetzung, einer Zusammenfassung der Erkenntnisse sowie einer kritischen Reflexion der Ergebnisse und angewandten Methoden
Ion charge separation with new generation of nuclear emulsion films
Get PDFIn hadron therapy, the accelerated ions, interacting with the body of the patient, cause the fragmentation of both projectile and target nuclei. The fragments interact with the human tissues depositing energy both in the entrance channel and in the volume surrounding the tumor. The knowledge of the fragments features is crucial to determine the energy amount deposited in the human body, and - hence - the damage to the organs and to the tissues around the tumor target.
The FOOT (FragmentatiOn Of Target) experiment aims at studying the fragmentation induced by the interaction of a proton beam (150-250 MeV/n) inside the human body. The FOOT detector includes an electronic setup for the identification of Z ≥ 3 fragments integrated with an emulsion spectrometer to measure Z ≤ 3 fragments. Charge identification by nuclear emulsions is based on the development of techniques of controlled fading of the particle tracks inside the nuclear emulsion, that extend the dynamical range of the films developed for the tracking of minimum ionising particles. The controlled fading strongly depends on temperature, relative humidity and treatment duration.
In this study the performances in terms of charge separation of proton, helium and carbon particles, obtained on a batch of new emulsion films produced in Japan are reported
Pushing the limits of nanopore transport performance by polymer functionalization
Get PDFInspired by the design and performance of biological pores, polymer functionalization of nanopores has emerged as an evolving field to advance transport performance within the last few years. This feature article outlines developments in nanopore functionalization and the resulting transport performance including gating based on electrostatic interaction, wettability and ligand binding, gradual transport controlled by polymerization as well as functionalization-based asymmetric nanopore and nanoporous material design going towards the transport direction. Pushing the limits of nanopore transport performance and thus reducing the performance gap between biological and technological pores is strongly related to advances in polymerization chemistry and their translation into nanopore functionalization. Thereby, the effect of the spatial confinement has to be considered for polymer functionalization as well as for transport regulation, and mechanistic understanding is strongly increased by combining experiment and theory. A full mechanistic understanding together with highly precise nanopore structure design and polymer functionalization is not only expected to improve existing application of nanoporous materials but also opens the door to new technologies. The latter might include out of equilibrium devices, ionic circuits, or machine learning based sensors
What Do Characters Do? The Embodied Agency of Fictional Characters
Get PDFThis paper uses machine learning to provide the first ever largescale
estimates of the distribution of actions of literary characters. Learning
more about these distributions can help us better understand how different
genres, cultures and time periods simulate personhood, i.e. what it means
to be an agent in the world. Prior research has emphasized fiction’s capacity
to promote ”social cognition” (Theory of Mind) on the part of readers, where
the complex cognitive states of literary characters are thought to facilitate
deeper reasoning about human motivations and behavior. The data and models
used here add an important dimension to this theory by highlighting how the
actions that have increasingly distinguished fictional characters from their nonfictional
counterparts over time entail forms of embodiment rather than explicit
invocations of cognitive or emotional behavior. These results suggest that
embodiment has emerged as a central value in the fictional representation of
personhood
The Impact of Product Packaging Characteristics on Order Picking Performance in Grocery Retailing
Get PDFIncreasing labor cost levels and workforce shortages have caused retailers to pay increased attention to their order‐fulfillment operations, which continue to largely depend on manual order picking systems. The operations and logistics management literature suggests that optimizing tertiary packaging, which groups products into full unit loads for storage and shipping, is an important way to improve order picking performance. While most retailers handle products at the level of secondary packaging when fulfilling orders, this packaging level remains largely unexplored. To address this gap, we analyze 3,380,596 picks performed by 185 order pickers of 4957 products in a grocery retail warehouse in Germany. Our findings indicate that secondary packaging characteristics directly affect order picking performance and that this effect is moderated by traditional product characteristics (e.g., product weight and volume), as well as elements of warehouse design (e.g., pick and stack levels). From a managerial perspective, our findings may help to bridge the gap between logistics managers and packaging engineers and provoke further research on the trade‐off between operational and environmental performance
Laser‐Writing of Fluorescent Copolymers in Mesoporous Silica Thin Films
Get PDFLocal polymer grafting, as well as automated direct laser writing (DLW) of polymers in mesoporous films, is demonstrated. Especially when low polymer amounts are grafted at a very small scale, analysis of polymer functionalization is a challenge. DLW of fluorescent copolymer is presented in mesoporous silica with 12 nm mesopore diameter by a surface‐initiated photo electron/energy transfer‐reversible addition‐fragmentation chain‐transfer (PET‐RAFT) polymerization using a 405 nm laser of a commercially available microscope. By the copolymerization of fluorescent comonomers during DLW, fluorescent microscale patterns of copolymer of sulfopropyl acrylate (SPA) and fluorescein methacrylate (FLMA) are obtained. The polymer spot sizes, as well as the polymer amount, are precisely manipulated by adjusting the irradiation time or power. A method for the analysis of confocal fluorescence image data is introduced, allowing quantitative comparison of relative polymer amounts by the correlation of fluorescence intensities and polymer specific IR absorption intensities. In addition, profiles of spatial polymer distribution on the micrometer scale are deduced from fluorescence image data and investigated. The polymer spot analysis shows that polymer amount gradients within each micrometer sized polymer spot are precisely tuned using irradiation time and laser power
Continuous-wave 1550 nm operated terahertz system using ErAs:In(Al)GaAs photo-conductors with 52 dB dynamic range at 1 THz
Get PDFTelecom-wavelength compatible photoconductors benefit strongly from the large amount and affordability of telecom lasers and components but there are demanding requirements on material development. We demonstrate continuous-wave (CW) photomixing with a setup that only uses ErAs:In(Al)GaAs devices with a peak dynamic range (DNR) of 78 dB and a bandwidth of ∼3.65 THz at an integration time of 300 ms and only 26 mW laser power on each device. The ErAs:InGaAs receiver further features a factor of two lower noise equivalent power (NEP) than a state-of-the-art photoconductor, despite an antenna mismatch
A Conditionally Activated Cytosol-Penetrating Antibody for TME-Dependent Intracellular Cargo Delivery
Get PDFCurrently, therapeutic and diagnostic applications of antibodies are primarily limited to cell surface-exposed and extracellular proteins. However, research has been conducted on cell-penetrating peptides (CPP), as well as cytosol-penetrating antibodies, to overcome these limitations. In this context, a heparin sulfate proteoglycan (HSPG)-binding antibody was serendipitously discovered, which eventually localizes to the cytosol of target cells. Functional characterization revealed that the tested antibody has beneficial cytosol-penetrating capabilities and can deliver cargo proteins (up to 70 kDa) to the cytosol. To achieve tumor-specific cell targeting and cargo delivery through conditional activation of the cell-penetrating antibody in the tumor microenvironment, a single-chain Fc fragment (scFv) and a VL domain were isolated as masking units. Several in vitro assays demonstrated that fusing the masking protein with a cleavable linker to the cell penetration antibody results in the inactivation of antibody cell binding and internalization. Removal of the mask via MMP-9 protease cleavage, a protease that is frequently overexpressed in the tumor microenvironment (TME), led to complete regeneration of binding and cytosol-penetrating capabilities. Masked and conditionally activated cytosol-penetrating antibodies have the potential to serve as a modular platform for delivering protein cargoes addressing intracellular targets in tumor cells
Elucidating the Mechanism of the Reverse Water–Gas Shift Reaction over Au/CeO₂ Catalysts Using Operando and Transient Spectroscopies
No full textThe reaction mechanism of the reverse water–gas shift reaction (rWGSR) over Au/ceria catalysts was investigated by monitoring the catalyst dynamics and reaction intermediates using operando and transient spectroscopies, as well as by DFT calculations. Combined operando Raman and UV-Vis spectroscopic analysis allows establishing a correlation between subsurface oxygen vacancies and catalytic activity. Comparison of different ceria support materials, i.e., polyhedra and polycrystalline sheets, reveals that the defect concentration is not rate-determinant. Using transient DRIFTS, we are able to identify individual steps of hydrogen dissociation on supported gold and to gain detailed insight into the reduction of CO₂ via formate and carbonate formation. It is demonstrated that CO₂ reduction is influenced by the surface pretreatment. Considering all spectroscopic findings, we propose an associative mechanism via carbonate and formate intermediates as the main route for the rWGSR over Au/ceria(111) catalysts, while a redox mechanism plays only a minor role