178 Works

A host-vector toolbox for improved secretory protein overproduction in bacillus subtilis

Anna Krüger, Norma Welsch, Alexandra Dürwald, Henrike Brundiek, Rainer Wardenga, Henning Piascheck, Hendrik G. Mengers, Jana Krabbe, Sandra Beyer, Johannes Kabisch, Lutz Popper, Tanno Hübel, Garabed Antranikian & Thomas Schweder
Abstract: Target proteins in biotechnological applications are highly diverse. Therefore, versatile flexible expression systems for their functional overproduction are required. In order to find the right heterologous gene expression strategy, suitable host-vector systems, which combine different genetic circuits, are useful. In this study, we designed a novel Bacillus subtilis expression toolbox, which allows the overproduction and secretion of potentially toxic enzymes. This toolbox comprises a set of 60 expression vectors, which combine two promoter variants,...

Improvement of glycine biosynthesis from one-carbon compounds and ammonia catalyzed by the glycine cleavage system in vitro

Yingying Xu, Jie Ren, Wei Wang & An-Ping Zeng
Glycine cleavage system (GCS) plays a central role in one-carbon (C1) metabolism and receives increasing interest as a core part of the recently proposed reductive glycine pathway (rGlyP) for assimilation of CO2 and formate. Despite decades of research, GCS has not yet been well understood and kinetic data are barely available. This is to a large degree because of the complexity of GCS, which is composed of four proteins (H, T, P, and L) and...

Wafer-scale electroactive nanoporous silicon : large and fully reversible electrochemo-mechanical actuation in aqueous electrolytes

Manuel Brinker & Patrick Huber
Nanoporosity in silicon results in interface-dominated mechanics, fluidics, and photonics that are often superior to the ones of the bulk material. However, their active control, for example, by electronic stimuli, is challenging due to the absence of intrinsic piezoelectricity in the base material. Here, for large-scale nanoporous silicon cantilevers wetted by aqueous electrolytes, electrosorption-induced mechanical stress generation of up to 600 kPa that is reversible and adjustable at will by potential variations of ≈1 V...

Optimizing fuel consumption on inland waterway networks : local search heuristic for lock scheduling

Julian Golak, Christof Defryn & Alexander Grigoriev

What’s important for relationship management? : the mediating roles of relational trust and satisfaction for loyalty of cooperative banks’ customers

Svenja Damberg, Manfred Schwaiger & Christian M. Ringle
Building on the corporate reputation model, this study investigates the drivers of customer-based corporate reputation. We consider two corporate reputation dimensions (i.e., the cognitive dimension competence and the affective dimension likeability, and their effects on customer satisfaction and loyalty). Adapting the model to the banking sector, we theoretically extend this model by reasoning that customer satisfaction and relational trust are mediators of the relationship between the two corporate reputation dimensions and loyalty. Studying a sample...

Production of polylactic acid aerogels via phase separation and supercritical CO2 drying: thermodynamic analysis of the gelation and drying process

Alberto Bueno Morales, Christian Lübbert, Sabine Enders, Gabriele Sadowski & Irina Smirnova
The application range of aerogels, especially in the life-science sector, can be extended by utilizing biocompatible polymers such as polylactic acid (PLA). However, the low glass transition temperature (Tg) of PLA and the challenging gelation techniques limit the application of supercritical CO2 (scCO2) drying and thus the PLA-aerogel production. The aim of this work is to overcome this challenge and to provide a better understanding of the thermodynamics of the process. Therefore, the gelation of...

Unprecedented thermal stability of plasmonic titanium nitride films up to 1400 °C

Tobias Krekeler, Surya Snata Rout, Gnanavel Vaidhyanathan Krishnamurthy, Michael Störmer, Mahima Arya, Ankita Ganguly, Duncan S. Sutherland, Sergey Bozhevolnyi, Martin Ritter, Kjeld Pedersen, Alexander Petrov, Manfred Eich & Manohar Chirumamilla
Titanium nitride (TiN) has emerged as one of the most promising refractory materials for plasmonic and photonic applications at high temperatures due to its prominent optical properties along with mechanical and thermal stability. From a high temperature standpoint, TiN is a substitution for Au and Ag in the visible to near-infrared wavelength range, with potential applications including thermophotovoltaics, thermoplasmonics, hot-electron and high temperature reflective coatings. However, the optical properties and thermal stability of TiN films...

Probabilistic analysis of additively manufactured polymer lattice structures

Sven Drücker, Julian Kajo Lüdeker, Marvin Blecken, Arne Kurt, Kirill Betz, Benedikt Kriegesmann & Bodo Fiedler

An empirical study on stress-based fail-safe topology optimization and multiple load path design

Micah Kranz, Julian Kajo Lüdeker & Benedikt Kriegesmann
Explicitly considering fail-safety within design optimization is computationally very expensive, since every possible failure has to be considered. This requires solving one finite element model per failure and iteration. In topology optimization, one cannot identify potentially failing structural members at the beginning of the optimization. Hence, a generic failure shape is applied to every possible location inside the design domain. In the current paper, the maximum stress is considered as optimization objective to be minimized,...

Evolution of length scales and of chemical heterogeneity during primary and secondary dealloying

Yong Li, Dinh Bao Nam Ngo, Jürgen Markmann & Jörg Weissmüller
We study the evolution of silver-rich regions, or ‘clusters’, during the making of nanoporous gold by dealloying. The clusters, which are remnants of the master alloy that have evaded corrosion, impact the functional behavior of the material. Furthermore, they carry information on the structure size in the initial stages of dealloying. Using kinetic Monte Carlo simulations, we emulate electrochemical dealloying at various electrode potentials. Our simulations illustrate the two-stage character of the process, where primary...

Quantification of fructans in cereal-based bioethanol stillage based on a simplified analytical method

Andreas Zimmermann & Martin Kaltschmitt
Background and Objectives Cereal-based bioethanol stillage, the main by-product of industrial bioethanol production, is a potential substrate for fructans. However, the quantification of fructans in such complex sample matrices is still a challenge for the corresponding analytics to be overcome to allow for the identification and utilization of such unused fructan sources. Especially a possible utilization or rather the corresponding process development requires appropriate analytics first. Thus, this paper aims to develop and apply a...

Experimental investigation of transient thermal characteristics of a dry friction clutch using alternative friction materials under different operating conditions

Jenan S. Sherzaa, Ihsan Y. Hussain & Oday Ibraheem Abdullah
Abstract The thermal characteristics of four types of dry friction clutch materials (LUK, G95, HCC, and Tiger) are investigated experimentally and numerically in the present work under different working conditions; such as initial sliding angular velocity (ωro), torque (T), and sliding time (ts). The temperature distributions over a cross‐section of friction clutch elements (pressure plate and flywheel) are investigated and optimized during the sliding period (heating phase), and full engagement period (cooling phase). The effect...

Procedural synthetic training data generation for AI-based defect detection in industrial surface inspection

Ole Schmedemann, Melvin Baaß, Daniel Schoepflin & Thorsten Schüppstuhl
Supervised machine learning methods are increasingly used for detecting defects in automated visual inspection systems. However, these methods require large quantities of annotated image data of the surface being inspected, including images of defective surfaces. In industrial contexts, it is difficult to collect the latter since acquiring sufficient image data of defective surfaces is costly and time-consuming. Additionally, gathered datasets tend to contain selection-bias, e.g. under representation of certain defect classes, and therefore result in...

EmRep: energy management relying on state‐of‐charge extrema prediction

Lars Hanschke & Bernd-Christian Renner
The persistent rise of Energy Harvesting Wireless Sensor Networks entails increasing demands on the efficiency and configurability of energy management. New applications often profit from or even require user-defined time-varying utilities, for example, the health assessment of bridges is only possible at rushhour. However, monitoring times do not necessarily overlap with energy harvest periods. This misalignment is often corrected by over-provisioning the energy storage. Favourable small-footprint and cheap energy storage, however, fill up quickly and...

Einsatzpotenziale von Transportrobotern in der urbanen Logistik aus Anwendungsperspektive

David Grunow, Sandra Tjaden, Lukas Weber & Julia Wolf
Automatisierte Roboter werden als eine potenzielle technologische Transportlösung in der urbanen Logistik gesehen. In diesem Artikel erfolgt eine explorative Analyse praktischer Einsatzpotenziale von Transportrobotern aus Sicht möglicher AnwenderInnen mithilfe von Leitfadeninterviews. Die Interviews zeigen, dass die Fachkundigen ein breit gefächertes Bild von Einsatzmöglichkeiten sehen, welche jedoch unterschiedlichen Anforderungen unterliegen. Der Artikel leistet einen Beitrag zur Implementierungsphase von Transportrobotern.

A secure and extensible blockchain-based data provenance framework for the Internet of things

Marten Sigwart, Michael Borkowski, Marco Peise, Stefan Schulte & Stefan Tai
As data collected and provided by Internet of Things (IoT) devices power an ever-growing number of applications and services, it is crucial that this data can be trusted. Data provenance solutions combined with blockchain technology are one way to make data more trustworthy by providing tamper-proof information about the origin and history of data records. However, current blockchain-based solutions for data provenance fail to take the heterogeneous nature of IoT applications and their data into...

Enhanced sequestration of carbon dioxide into calcium carbonate using pressure and a carbonic anhydrase from alkaliphilic Coleofasciculus chthonoplastes

Jonas Heuer, Yasemin Kraus, Marijan Vučak & An-Ping Zeng
CO2 in the atmosphere is a major contributor to global warming but at the same time it has the potential to be a carbon source for advanced biomanufacturing. To utilize CO2, carbonic anhydrase has been identified as a key enzyme. Furthermore, attempts have been made to accelerate the sequestration via pressure. This study aims to combine both approaches to achieve high sequestration rates. The carbonic anhydrase of the alkaliphilic cyanobacterium Coleofasciculus chthonoplastes (cahB1) and bovine...

Coexistence of inverse and direct energy cascades in faraday waves

Raffaele Colombi, Niclas Rohde, Michael Schlüter & Alexandra von Kameke
In nature, turbulent flows exist that are neither simply 2D nor 3D but are forced towards one state or the other by boundary conditions such as varying stratification. Here, we report the first evidence of the co-existence of an inverse and a direct energy cascade in an experimental flow driven by Faraday waves in water. We find that an inverse energy cascade at the fluid surface and a direct energy cascade in the 3D bulk...

Analysis of semi-open queueing networks using lost customers approximation with an application to robotic mobile fulfilment systems

Sonja Otten, Ruslan Krenzler, Lin Xie, Hans Daduna & Karsten Kruse
We consider a semi-open queueing network (SOQN), where one resource from a resource pool is needed to serve a customer. If on arrival of a customer some resource is available, the resource is forwarded to an inner network to complete the customer’s order. If no resource is available, the new customer waits in an external queue until one becomes available (“backordering”). When a resource exits the inner network, it is returned to the resource pool....

Microbially promoted calcite precipitation in the pelagic redoxcline: elucidating the formation of the turbid layer

Kerstin Leberecht, Simon Michael Ritter, Christian Jonas Lapp, Lukas Klose, Julian Eschenröder, Christian Scholz, Sebastian Kühnel, Wolfgang Stinnesbeck, Arnulf Kletzin, Margot Isenbeck-Schröter & Johannes Gescher
Large bell-shaped calcite formations called “Hells Bells” were discovered underwater in the stratified cenote El Zapote on the Yucatán Peninsula, Mexico. Together with these extraordinary speleothems, divers found a white, cloudy turbid layer into which some Hells Bells partially extend. Here, we address the central question if the formation of the turbid layer could be based on microbial activity, more specifically, on microbially induced calcite precipitation. Metagenomic and metatranscriptomic profiling of the microbial community in...

Periodic hill flow simulations with a parameterized cumulant lattice Boltzmann method

Martin Gehrke & Thomas Rung
The article is concerned with the assessment of a cumulant lattice Boltzmann method in wall-bounded, separated turbulent shear flows. The approach is of interest for its resolution-spanning success in turbulent channel flows without using a specific turbulence treatment. The assessment focuses upon the flow over a periodic hill, which offers a rich basis of numerical and experimental data, for Reynolds numbers within (Formula presented.). The analysis involves the mean flow field, second moments and their...

Physicochemical investigation of rainfall for managed aquifer recharge in Punjab (Pakistan)

Ghulam Zakir-Hassan, Jehangir F. Punthakey, Ghulam Shabir, Fozia Yasmeen, Muhammad Sultan, Hadeed Ashraf, Sohoo Ihsanullah & Faizan Majeed
In a water-scarce country such as Pakistan, rainfall is the third-largest source of freshwater. In most of the urban cities of the country, rainwater is mixed with sewerage and is rendered useless for managed aquifer recharge purposes. Therefore, this study investigates the rainfall potential for managed aquifer recharge in Lahore (Pakistan). The present research was designed and conducted by the Irrigation Research Institute (IRI). Three different sites were selected for rainwater sample collection across the...

Process intensification by integration of distillation and vapor permeation or pervaporation - an academic and industrial perspective

Shun Liu, Hong Li, Bettina Kruber, Mirko Skiborowski & Xin Gao
Since membrane separations, such as vapor permeation (VP) or pervaporation (PV), are not limited by vapor-liquid equilibrium, their coupling with distillation can exert a synergistic effect, overcome the thermodynamic limits of distillation, and improve energy efficiency, especially suitable for the separation of azeotropic mixtures that otherwise requires special distillation processes. Therefore, there is an increasing number of such studies, and it is of great significance to comprehensively explore the process integration of distillation with VP...

3D-printing technology as a tool for medical implantable electronic devices

Pablo Daniel Mendoza Ponce, Lait Abu Saleh, Wolfgang Krautschneider & Matthias Kuhl
Medical implantable electronic devices (IMD) are of great use to research and in the treatment of various health conditions. 3D printing technology is proving to revolutionize multiple industries, including IMDs, by allowing rapid research, development and production. This paper presents how 3D printing technology was utilized during the modeling, prototyping and fabrication process of the first version of an implantable device intended for interstitial pressure monitoring.

Shift of the reaction equilibrium at high pressure in the continuous synthesis of neuraminic acid

Jannis Alexander Reich, Miriam Aßmann, Kristin Hölting, Paul Bubenheim, Jürgen Kuballa & Andreas Liese
The importance of a compound that helps fight against influenza is, in times of a pandemic, self-evident. In order to produce these compounds in vast quantities, many researchers consider continuous flow reactors in chemical industry as next stepping stone for large scale production. For these reasons, the synthesis of N-acetylneuraminic acid (Neu5Ac) in a continuous fixed-bed reactor by an immobilized epimerase and aldolase was investigated in detail. The immobilized enzymes showed high stability, with half-life...

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  • Journal Article