Fachbereich Ingenieur- und Naturwissenschaften
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There are already several tools available to generate traffic demand for the microscopic simulation suite SUMO. This paper focuses on setting up a simulation scenario for the peak hour in a small conurbation when there are vehicle counts available for the major streets. We describe tools which are part of SUMO or available as open source and compare their results with the real traffic counts as well as with the outcome of countless demand generation.
New technologies leading to better and more efficient light emitting diodes. The emitted radiation reaches higher energy levels and lower wavelengths especially in the UV-C spectrum. UV-C light has a cancer inducing effect on human cells. Therefore it is necessary to work in a safe way with those devices.
This work is focused on an open-source solution for rapid 3D printing of an safe UV-C radiation measuring device. Especially for research groups or universities which can not afford big safety labs.
After modeling and printing the prototype, a series of tests has shown the functionality of that UV-C Diode test system. By using black printing filaments and infill rates over 50 %, the transmission of light could be prevented and the system worked well.
The first atomic layer deposition process for a ternary oxide is reported, which contains a metal of the platinum group, the delafossite PtCoO2. The deposition with the precursors trimethyl-Pt-methylcyclopentadienyl, Co-bis(N-t-butyl-N′-ethylpropanimidamidate), and oxygen plasma results in a process with a nearly constant growth rate and stoichiometric composition over a wide temperature window from 100 to 320 °C. Annealing of the as-deposited amorphous films in an oxygen atmosphere in a temperature window from 700 to 800 °C leads to the formation of the delafossite phase. Very thin films show a pronounced preferred orientation with the Pt sheets being almost parallel to the substrate surface while arbitrary orientation is observed for thicker films. The conformal coating of narrow trenches highlights the potential of this atomic-layer-deposition process. Moreover, heterostructures with magnetic films are fabricated to demonstrate the potential of PtCoO2 for spintronic applications.
The article discusses the approach to solving the problem of reducing time spent on the preparation of medical images for teaching neural networks, by reducing the time of creating masks for images. The task is considered on the example of processing images of the mucous membrane of the paranasal sinus. The specifics of the task did not allow effectively using existing software solutions. During the study, a software solution was proposed, which made it possible to radically reduce the time of creating masks for images. The article also analyzes the shortcomings of the automated creation of masks, as well as the directions of their solution. The loss of time due to the adjustment of the color palette can be reduced even more to 1-2 minutes, the average deviation is 7.61%.
Bio-inorganic hybrid structures for direct electron transfer to photosystem I in photobioelectrodes
(2022)
Synthetic materials can be combined with biological components in many ways. One example that provides scientists with multiple challenges is a photobioelectrode that converts sunlight into electrons in a biohybrid approach. In the present study several key parameters are evaluated concerning their influence on the direct electron transfer from a 3D indium tin oxide (ITO) electrode material to photosystem I (PSI) as a light-harvesting biomolecule. In contrast to previous investigations, no mediating molecule is added to shuttle the electrons to the luminal side of PSI. Thus, this setup is less complex than foregoing ones. The solution composition drastically influences the interaction of PSI with the ITO surface. Here, the application of higher buffer concentrations and the addition of salts are advantageous, whereas the nature of the buffer ions plays a minor role. The artificial electrode material's thickness is adjustable since a spin-coating procedure is used for preparation. With a 30 μm thick structure and immobilized PSI cathodic photocurrents up to 10.1 μA cm−2 are obtained at 100 mW cm−2 illumination intensity and an applied potential of −0.1V vs. Ag/AgCl. Over a period of three days the photobioelectrodes are illuminated for a total of 90 min and stored between the measurements at ambient temperature. The stability of the setup is noteworthy as still about 90% of the photocurrent is retained. The photocathode described here offers many positive features, including a high onset potential for the photocurrent starting sligthly above the redox potentail of P700, and applicability in a wide pH range from pH 5 to 8.
Facing an inexorable growth of the human population along with substantial environmental changes, the assurance of food security is a major challenge of the present century. To ensure responsible food consumption and production (SDG 12), new approaches in the food system are required. Thus, environmentally controlled, sustainable production of alternative food sources are of key interest for both urban agriculture and food research. To face the current challenge of integrating food production systems within existing structures, multidisciplinary discourses are required. Here, we bring together novel technologies and indoor farming techniques with the aim of supporting the development of sustainable food production systems. For this purpose, we investigated the feasibility of 10 composite materials for their innovative use as structural support in macroalgal cultivation (settlement substrates) and cricket rearing (housing). Considering material resistance, rigidity, and direct material-organism interactions, the bio-based composite polylactic acid (PLA) was identified as a suitable material for joint farming. For macroalgae cultivation, PLA sustained the corrosive cultivation conditions and provided a suitable substrate without affecting the macroalgal physiology or nutritional composition (carotenoids and chlorophylls). For cricket rearing, PLA provided a suitable and recyclable shelter, which was quickly accepted by the animals without any observed harm. In contrast, other common composite components like phenolic resin or aramid were found to be unsuitable due to being harmful for the cultivated organisms or instable toward the applied sterilization procedure. This multidisciplinary study not only provides profound insights in the developing field of urban indoor food production from a new perspective, but also bridges material science and farming approaches to develop new sustainable and resilient food production systems.
According to the drinking water regulation, drinking water systems must be tested for harmful contamination at specified intervals. To meet the legal requirements and save costs and time, a portable analysis method is to be developed. For this purpose, a concept study was conducted. It describes a portable measuring device for the quantitative detection of legionella using real-time PCR. The study includes the construction elements and conditions that are necessary for the collection, processing, and evaluation of the sample. It was found that commercially available PCR systems do not meet the size requirements and can only be represented by an in-house development. In addition, a microfluidic system must be developed that is designed for one-time use and low production cost.
Knowledge of optical constants, i.e. refractive index n and extinction coefficient k, and light scattering properties of optical polymers are required to optimize micro-optics for light-emitting diodes in terms of efficiency, color properties and light distribution. We present here a model-based diagnostic approach to determine the optical properties of polymers, which should be particularly useful in the development of plastics for optical applications. Optical constants and scattering coefficients were obtained from transmission and reflection measurements in a wavelength range from UV to NIR taking into account scattering effects due to rough surfaces and volume inhomogeneity. Based on the models for the dielectric function, the molecular optical transition energies Eg, critical point energies, Urbach energies and exciton transition energies were determined. Rayleigh and Mie scattering model and van de Hulst's anomalous diffraction theory were applied to characterize scattering due to volume inhomogeneities. Scalar diffraction theory was applied to account for surface roughness scattering. Atomic force microscopy with nanomechanical characterization was used to characterize domains in size and shape and to assign optical scattering to a suitable morphological model. The combined optical and mechanical characterization help to improve the qualification of new polymer materials for optical applications.
Der Fachkräftemangel im Gesundheitssektor beschleunigt die Digitalisierung, wodurch die Anforderungen an das Personal steigen. Die zunehmenden technischen Möglichkeiten verändern die notwendigen Kompetenzen an die Ärzte in Richtung Digitalisierung. Daher sollten im Personal-Recruitment digitale Kompetenzen bereits in den Stellenausschreibungen berücksichtigt werden, um die zukünftigen Herausforderungen bewältigen zu können. Dieser Beitrag untersucht, inwieweit a) digitale Kompetenzen bereits in den am Markt befindlichen Stellenprofilen von Ärzten Eingang gefunden haben und b) ob diese durch einen datengetriebenen methodischen Ansatz sinnvoll extrahiert werden können. Dabei werden 1707 Stellenanzeige mit der Latent Semantic Analysis (LSA) ausgewertet. Die unterschiedlichen methodischen Ansätze innerhalb der LSA zeigen, dass kaum ein Fokus auf digitale Kompetenzen im Gesundheitssektor bei Stellenausschreibungen besteht.
The development of precision cancer medicine relies on novel formulation strategies for targeted drug delivery to increase the therapeutic outcome. Biocompatible polymer nanoparticles, namely dextran-graft-polyacrylamide (D-g-PAA) copolymers, represent one of the innovative non-invasive approaches for drug delivery applications in cancer therapy. In this study, the star-like D-g-PAA copolymer in anionic form (D-g-PAAan) was developed for pH-triggered targeted drug delivery of the common chemotherapeutic drugs – doxorubicin (Dox) and cisplatin (Cis). The initial D-g-PAA copolymer was synthesized by the radical graft polymerization method, and then alkaline-hydrolyzed to get this polymer in anionic form for further use for drug encapsulation. The acidification of the buffer promoted the release of loaded drugs. D-g-PAAan nanoparticles increased the toxic potential of the drugs against human and mouse lung carcinoma cells (A549 and LLC), but not against normal human lung cells (HEL299). The drug-loaded D-g-PAAan-nanoparticles promoted further oxidative stress and apoptosis induction in LLC cells. D-g-PAAan-nanoparticles improved Dox accumulation and drugs’ toxicity in a 3D LLC multi-cellular spheroid model. The data obtained indicate that the strategy of chemotherapeutic drug encapsulation within the branched D-g-PAAan nanoparticle allows not only to realize pH-triggered drug release but also to potentiate its cytotoxic, prooxidant and proapoptotic effects against lung carcinoma cells.