Showing papers by "Braunschweig University of Technology published in 2022"

Human serum from SARS-CoV-2-vaccinated and COVID-19 patients shows reduced binding to the RBD of SARS-CoV-2 Omicron variant

Abstract: The COVID-19 pandemic is caused by the betacoronavirus SARS-CoV-2. In November 2021, the Omicron variant was discovered and immediately classified as a variant of concern (VOC), since it shows substantially more mutations in the spike protein than any previous variant, especially in the receptor-binding domain (RBD). We analyzed the binding of the Omicron RBD to the human angiotensin-converting enzyme-2 receptor (ACE2) and the ability of human sera from COVID-19 patients or vaccinees in comparison to Wuhan, Beta, or Delta RBD variants.All RBDs were produced in insect cells. RBD binding to ACE2 was analyzed by ELISA and microscale thermophoresis (MST). Similarly, sera from 27 COVID-19 patients, 81 vaccinated individuals, and 34 booster recipients were titrated by ELISA on RBDs from the original Wuhan strain, Beta, Delta, and Omicron VOCs. In addition, the neutralization efficacy of authentic SARS-CoV-2 wild type (D614G), Delta, and Omicron by sera from 2× or 3× BNT162b2-vaccinated persons was analyzed.Surprisingly, the Omicron RBD showed a somewhat weaker binding to ACE2 compared to Beta and Delta, arguing that improved ACE2 binding is not a likely driver of Omicron evolution. Serum antibody titers were significantly lower against Omicron RBD compared to the original Wuhan strain. A 2.6× reduction in Omicron RBD binding was observed for serum of 2× BNT162b2-vaccinated persons. Neutralization of Omicron SARS-CoV-2 was completely diminished in our setup.These results indicate an immune escape focused on neutralizing antibodies. Nevertheless, a boost vaccination increased the level of anti-RBD antibodies against Omicron, and neutralization of authentic Omicron SARS-CoV-2 was at least partially restored. This study adds evidence that current vaccination protocols may be less efficient against the Omicron variant.

Fast and noninvasive electronic nose for sniffing out COVID-19 based on exhaled breath-print recognition

Abstract: The reverse transcription-quantitative polymerase chain reaction (RT-qPCR) approach has been widely used to detect the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, instead of using it alone, clinicians often prefer to diagnose the coronavirus disease 2019 (COVID-19) by utilizing a combination of clinical signs and symptoms, laboratory test, imaging measurement (e.g., chest computed tomography scan), and multivariable clinical prediction models, including the electronic nose. Here, we report on the development and use of a low cost, noninvasive method to rapidly sniff out COVID-19 based on a portable electronic nose (GeNose C19) integrating an array of metal oxide semiconductor gas sensors, optimized feature extraction, and machine learning models. This approach was evaluated in profiling tests involving a total of 615 breath samples composed of 333 positive and 282 negative samples. The samples were obtained from 43 positive and 40 negative COVID-19 patients, respectively, and confirmed with RT-qPCR at two hospitals located in the Special Region of Yogyakarta, Indonesia. Four different machine learning algorithms (i.e., linear discriminant analysis, support vector machine, stacked multilayer perceptron, and deep neural network) were utilized to identify the top-performing pattern recognition methods and to obtain a high system detection accuracy (88-95%), sensitivity (86-94%), and specificity (88-95%) levels from the testing datasets. Our results suggest that GeNose C19 can be considered a highly potential breathalyzer for fast COVID-19 screening.

Thermal tolerance and acclimation capacity in the European common frog ( <i>Rana temporaria</i> ) change throughout ontogeny

Abstract: Phenotypic plasticity may allow ectotherms with complex life histories such as amphibians to cope with climate-driven changes in their environment. Plasticity in thermal tolerance (i.e., shifts of thermal limits via acclimation to higher temperatures) has been proposed as a mechanism to cope with warming and extreme thermal events. However, thermal tolerance and, hence, acclimation capacity, is known to vary with life stage. Using the common frog (Rana temporaria) as a model species, we measured the capacity to adjust lower (CTmin ) and upper (CTmax ) critical thermal limits at different acclimation temperatures. We calculated the acclimation response ratio as a metric to assess the stage-specific acclimation capacity at each of seven consecutive ontogenetic stages and tested whether acclimation capacity was influenced by body mass and/or age. We further examined how acclimation temperature, body mass, age, and ontogenetic stage influenced CTmin and CTmax . In the temperate population of R. temporaria that we studied, thermal tolerance and acclimation capacity were affected by the ontogenetic stage. However, acclimation capacity at both thermal limits was well below 100% at all life stages tested. The lowest and highest acclimation capacity in thermal limits was observed in young and late larvae, respectively. The relatively low acclimation capacity of young larvae highlights a clear risk of amphibian populations to ongoing climate change. Ignoring stage-specific differences in thermal physiology may drastically underestimate the climate vulnerability of species, which will hamper successful conservation actions.

Sensitivity of soil respiration rate with respect to temperature, moisture and oxygen under freezing and thawing

Abstract: In alpine environments, the decomposition rate of soil organic carbon (SOC) is controlled by several biotic and abiotic factors, which mostly change simultaneously and often lead to freezing and thawing cycles. However, it is highly uncertain whether the temperature sensitivity of decomposition around the freezing point of water is similar as in higher temperature ranges. In this study, we conducted a full factorial incubation experiment using soil samples from a grassland site in the Tibetan Plateau. A manipulative freeze-thaw cycle was imposed to these soils by continuously changing temperature, from −5 to 10 °C. Additional treatments included 4 levels of soil moisture at 15, 30, 60 and 90% of water-filled pore space (WFPS), and two levels of O2 concentration at 0 and 20%. We fitted the Arrhenius equation into the flux data to estimate the activation energy (Ea) and base flux rate (A) for each treatment level. Then, we predicted the dependence and sensitivity of decomposition rate (k) by implementing the Dual Arrhenius and Michaelis-Menten (DAMM) model using a Bayesian optimization approach. While soil temperature had the strongest control on SOC decomposition rate at all soil moisture and O2 levels, its intrinsic temperature sensitivity (Δk/ΔT) remained nearly constant across the entire temperature range except around 0 °C. We found that Ea was higher in nearly dry or anoxic conditions, suggesting that in these extremes more energy is required for microbial activity to take place. These intrinsic sensitivities revealed that temperature (energy) is the main factor that limits decomposition in cold environments provided that moisture and oxygen are sufficiently available. Intrinsic sensitivities with respect to soil moisture and oxygen concentration were only relevant at very narrow ranges, when soils were almost dry or partially anoxic, and small changes within these narrow ranges may lead to very strong changes in decomposition rates.

Benchmarking soil organic carbon to support agricultural carbon management: A German case study#

Abstract: Background Soil organic carbon (SOC) storage is highly variable across sites and primarily depends on site properties and land use. It is therefore difficult for farmers to evaluate the actual SOC status of a site. To aid the interpretation of measured SOC contents, easy-to-use frameworks for the assessment of SOC contents are needed. Aims The aim of this study was to derive site-specific SOC benchmarks for German mineral soils under agricultural use based on the dataset of the first German Agricultural Soil Inventory. Methods The dataset was stratified into 33 strata by land use, soil texture, C/N ratio and mean annual precipitation. Lower and upper SOC benchmarks were calculated for all strata (0.125 and the 0.875 quantile). Results The SOC benchmark value ranges were lower for cropland (6.8–48.9 g kg–1) than for grassland (14.1–76.6 g kg–1), and increased with rising clay content and precipitation. Sandy soils with a wide C/N ratio and high SOC content due to their heathland or peatland history were divided into separate strata. The number of strata only decreased the SOC benchmark ranges slightly. Around 15–20 sites were required as a minimum to quantify SOC benchmarks for one stratum. Conclusions The presented framework is easy to use, requiring only four readily available stratification factors to perform a comparative classification of SOC contents. It allows farmers and extension services to compare where their measured SOC contents fall within the expected SOC value range for their site, and can thus help develop an initial evaluation of the SOC status of a site with regard to soil-specific differences.

LabPi: A Digital Measuring Station for STEM Education 4.0

Abstract: The acquisition of quantitative measurement data has been a challenge in chemistry education for a long time, as the required measurement devices are often too old, error-prone, complicated to operate, or simply too expensive. This paper presents the LabPi digital measurement station, which addresses this problem and provides a solution for science education, research, and teaching. It is built from inexpensive components, is modularly expandable, provides accurate measurements, and is easy for students and teachers to use. It also exploits the potential of digitization to make teaching–learning processes in the classroom as efficient as possible.

Formation of Comets

Abstract: Questions regarding how primordial or pristine the comets of the solar system are have been an ongoing controversy. In this review, we describe comets’ physical evolution from dust and ice grains in the solar nebula to the contemporary small bodies in the outer solar system. This includes the phases of dust agglomeration, the formation of planetesimals, their thermal evolution and the outcomes of collisional processes. We use empirical evidence about comets, in particular from the Rosetta Mission to comet 67P/Churyumov–Gerasimenko, to draw conclusions about the possible thermal and collisional evolution of comets.

Modular Link Level Simulator for the Physical Layer of Beyond 5G Wireless Communication Systems

Abstract: The low THz band is a promising candidate to enable data rates of up to 1 Tbit/s. To develop suitable communications systems, novel simulation approaches are needed that account for the specifics of the evolving technology. This article presents a modular link level simulator for the physical layer of beyond-5G and 6G wireless communication systems in the THz range. The simulator, that is oriented toward the IEEE Std 802.15.3d-2017 is contrasted to the state of the art of physical layer simulation tools. Its concept and basic building blocks are presented and the simulator is validated by channel simulations considering an AWGN channel model. Moreover, it is applied to a top-of-rack scenario in a wirelessly augmented data center. Different parameter sets are compared showing that a LOS condition and sufficient transmit power are a prerequisite in order to profit from the large bandwidth in the low THz range. The extensive data set of simulation results serves as input for future studies with higher layer simulation tools.

Nonhydrostatic Numerical Modeling of Fixed and Mobile Barred Beaches: Limitations of Depth-Averaged Wave Resolving Models around Sandbars

Abstract: Along sandy coastlines, submerged, shore-parallel sandbars play an essential role in shoreline morphology by dissipating wave energy through depth-induced wave breaking. While wave breakin...

All-in-one superparamagnetic and SERS-active niosomes for dual-targeted <i>in vitro</i> detection of breast cancer cells

Abstract: Encapsulation of iron oxide and gold nanoparticles into the bilayer structure of transferrin-modified niosomes enables greatly enhanced and contamination-free SERS-signals in vitro as well as a dual-targeting functionality towards cancer cells.

Assessing creep properties of asphalt binder, asphalt mastic and asphalt mixture

Abstract: In this article, creep properties of asphalt binders and asphalt mastics (binder filler composite) are tested in the Dynamic Shear Rheometer using a single shear creep test and considering steady-state flow conditions. These tests are performed for a set of 10 different asphalt binders and 18 corresponding asphalt mastics. The same material combinations are used to produce asphalt mixtures in the laboratory, which are then subjected to cyclic compression tests to assess the creep properties of the asphalt mixture. Finally, the creep properties resulting from asphalt binder tests, asphalt mastic tests and asphalt mixture tests are comparatively analysed in terms of the material-specific creep rates. The results show reasonable and sound correlations across the different material scales. The authors concluded that the asphalt binder has a significant impact on the creep behaviour of the corresponding asphalt mixture.

Integrated Concept for Analysis and Development of Sustainable Urban Production Systems

Abstract: Urban production systems are connected with the surrounding quarter, city and region through input and output flows of energy, materials and information. The analysis, purposeful design and coupling of these exchange flows can support minimizing the negative impacts induced by urban and production activities and enabling the generation of positive impacts. For an analysis and subsequent development of sustainable urban production system, an integrated approach is required b ased on the conceptual combination of the urban system and the factory system. For this purpose, a holistic urban factory system model is developed based on requirements deducted from the formulated research questions and hypotheses.

Apiaceae <i>FNS I</i> originated from <i>F3H</i> through tandem gene duplication

Abstract: Abstract Background Flavonoids are specialized metabolites with numerous biological functions in stress response and reproduction of plants. Flavones are one subgroup that is produced by the flavone synthase (FNS). Two distinct enzyme families evolved that can catalyze the biosynthesis of flavones. While the membrane-bound FNS II is widely distributed in seed plants, one lineage of soluble FNS I appeared to be unique to Apiaceae species. Results We show through phylogenetic and comparative genomic analyses that Apiaceae FNS I evolved through tandem gene duplication of flavanone 3-hydroxylase ( F3H ) followed by neofunctionalization. Currently available datasets suggest that this event happened within the Apiaceae in a common ancestor of Daucus carota and Apium graveolens . The results also support previous findings that FNS I in the Apiaceae evolved independent of FNS I in other plant species. Conclusion We validated a long standing hypothesis about the evolution of Apiaceae FNS I and predicted the phylogenetic position of this event. Our results explain how an Apiaceae-specific FNS I lineage evolved and confirm independence from other FNS I lineages reported in non-Apiaceae species.

Regional opening strategies with commuter testing and containment of new SARS-CoV-2 variants in Germany

Abstract: Despite the vaccination process in Germany, a large share of the population is still susceptible to SARS-CoV-2. In addition, we face the spread of novel variants. Until we overcome the pandemic, reasonable mitigation and opening strategies are crucial to balance public health and economic interests.We model the spread of SARS-CoV-2 over the German counties by a graph-SIR-type, metapopulation model with particular focus on commuter testing. We account for political interventions by varying contact reduction values in private and public locations such as homes, schools, workplaces, and other. We consider different levels of lockdown strictness, commuter testing strategies, or the delay of intervention implementation. We conduct numerical simulations to assess the effectiveness of the different intervention strategies after one month. The virus dynamics in the regions (German counties) are initialized randomly with incidences between 75 and 150 weekly new cases per 100,000 inhabitants (red zones) or below (green zones) and consider 25 different initial scenarios of randomly distributed red zones (between 2 and 20% of all counties). To account for uncertainty, we consider an ensemble set of 500 Monte Carlo runs for each scenario.We find that the strength of the lockdown in regions with out of control virus dynamics is most important to avoid the spread into neighboring regions. With very strict lockdowns in red zones, commuter testing rates of twice a week can substantially contribute to the safety of adjacent regions. In contrast, the negative effect of less strict interventions can be overcome by high commuter testing rates. A further key contributor is the potential delay of the intervention implementation. In order to keep the spread of the virus under control, strict regional lockdowns with minimum delay and commuter testing of at least twice a week are advisable. If less strict interventions are in favor, substantially increased testing rates are needed to avoid overall higher infection dynamics.Our results indicate that local containment of outbreaks and maintenance of low overall incidence is possible even in densely populated and highly connected regions such as Germany or Western Europe. While we demonstrate this on data from Germany, similar patterns of mobility likely exist in many countries and our results are, hence, generalizable to a certain extent.

Durable Fast Charging of Lithium-Ion Batteries Based on Simulations with an Electrode Equivalent Circuit Model

Abstract: Fast charging of lithium-ion batteries is often related to accelerated cell degradation due to lithium-plating on the negative electrode. In this contribution, an advanced electrode equivalent circuit model is used in order to simulate fast-charging strategies without lithium-plating. A novel parameterization approach based on 3-electrode cell measurements is developed, which enables precise simulation fidelity. An optimized fast-charging strategy without evoking lithium-plating was simulated that lasted about 29 min for a 0–80% state of charge. This variable current strategy was compared in experiments to a conventional constant-current–constant-voltage fast-charging strategy that lasted 20 min. The experiments showed that the optimized strategy prevented lithium-plating and led to a 2% capacity fade every 100 fast-charging cycles. In contrast, the conventional strategy led to lithium-plating, about 20% capacity fade after 100 fast-charging cycles and the fast-charging duration extended from 20 min to over 30 min due to increased cell resistances. The duration of the optimized fast charging was constant at 29 min, even after 300 cycles. The developed methods are suitable to be applied for any given lithium-ion battery configuration in order to determine the maximum fast-charging capability while ensuring safe and durable cycling conditions.

Urban Space, Production Systems and Sustainable Development

Abstract: Urban production as a conceptual understanding is rooted in several scientific disciplines, which traditionally are treated seperately. With definitions of urbanity, factories and their interfaces, a guiding frame can be laid out leading to the definition of urban production as synthesis. The identification of exchange flows and their resulting effects will enable new options and methods to foster sustainable development in cities with the concept of urban production.