Ingenieurwissenschaften
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- ItemLight-Regulated Pro-Angiogenic Engineered Living Materials(Weinheim : Wiley-VCH, 2023) Dhakane, Priyanka; Tadimarri, Varun Sai; Sankaran, ShrikrishnanRegenerative medicine aims to restore damaged cells, tissues, and organs, for which growth factors are vital to stimulate regenerative cellular transformations. Major advances have been made in growth factor engineering and delivery like the development of robust peptidomimetics and controlled release matrices. However, their clinical applicability remains limited due to their poor stability in the body and need for careful regulation of their local concentration to avoid unwanted side-effects. In this study, a strategy to overcome these limitations is explored using engineered living materials (ELMs), which contain live microorganisms that can be programmed with stimuli-responsive functionalities. Specifically, the development of an ELM that releases a pro-angiogenic protein in a light-regulated manner is described. This is achieved by optogenetically engineering bacteria to synthesize and secrete a vascular endothelial growth factor peptidomimetic (QK) linked to a collagen-binding domain. The bacteria are securely encapsulated in bilayer hydrogel constructs that support bacterial functionality but prevent their escape from the ELM. In situ control over the release profiles of the pro-angiogenic protein using light is demonstrated. Finally, it is shown that the released protein is able to bind collagen and promote angiogenic network formation among vascular endothelial cells, indicating the regenerative potential of these ELMs.
- ItemThe information procurement and publishing behaviour of researchers in the natural sciences and engineering : Evaluation of a survey focusing on non-textual material(Hannover : Technische Informationsbibliothek, 2017) Einbock, Joanna; Dreyer, Britta; Heller, Lambert; Kraft, Angelina; Niemeyer, Sandra; Plank, Margret; Schrenk, Philip; Sens, Irina; Struß, Julia; Tullney, Marco; Bernhofer, Carolin; Häfner, Peter[no abstract available]
- ItemComposite forming simulation for non-crimp fabrics based on generalized continuum approaches – AMECOMP : Abschlussbericht / Final project report (DFG 431354059 / ANR-19-CE06-0031)(Hannover : Technische Informationsbibliothek, 2024-05) Schäfer, Bastian; Kärger, Luise; Naouar, Naim; Zheng, Ruochen; Schäfer, Bastian; Kärger, Luise; Naouar, Naim; Zheng, Ruochen; Boisse, Philippe; Colmars, Julien; Platzer, AurianeContinuously carbon fiber reinforced composites are increasingly used for structural applications in various fields of engineering due to their excellent weight-specific mechanical properties. Non-crimp-fabrics (NCF) provide the highest lightweight potential as reinforcement for the composite due to their straight fibers, compared to woven fabrics with undulated fibers. NCFs are made of one (UD-NCF), two (Biax-NCF) or more directions of fibers linked together with a polymer stitching in specific patterns. The deformation behavior of NCFs is challenging due to the interaction between the fibers and the stitching, which also results in a higher susceptibility to forming effects such as roving slippage, fiber waviness and gapping compared to woven fabrics. The aim of the AMECOMP project was to improve the understanding of the forming behavior of NCFs and to develop suitable simulation models to broaden the range of potential applications. Mesoscopic models that accurately describe the architecture of the NCF were developed for virtual material characterization and detailed analysis of forming defects in critical areas. Macroscopic models that describe the relevant deformation mechanisms of NCF in a homogenized way were developed for efficient analysis of large components and multi-layer stacks.
- ItemFunctional two-dimensional high-entropy materials(London : Springer Nature, 2023) Nemani, Srinivasa Kartik; Torkamanzadeh, Mohammad; Wyatt, Brian C.; Presser, Volker; Anasori, BabakMultiple principal element or high-entropy materials have recently been studied in the two-dimensional (2D) materials phase space. These promising classes of materials combine the unique behavior of solid-solution and entropy-stabilized systems with high aspect ratios and atomically thin characteristics of 2D materials. The current experimental space of these materials includes 2D transition metal oxides, carbides/carbonitrides/nitrides (MXenes), dichalcogenides, and hydrotalcites. However, high-entropy 2D materials have the potential to expand into other types, such as 2D metal-organic frameworks, 2D transition metal carbo-chalcogenides, and 2D transition metal borides (MBenes). Here, we discuss the entropy stabilization from bulk to 2D systems, the effects of disordered multi-valent elements on lattice distortion and local electronic structures and elucidate how these local changes influence the catalytic and electrochemical behavior of these 2D high-entropy materials. We also provide a perspective on 2D high-entropy materials research and its challenges and discuss the importance of this emerging field of nanomaterials in designing tunable compositions with unique electronic structures for energy, catalytic, electronic, and structural applications.
- ItemIs there more than one stickiness criterion?(Berlin ; Heidelberg : Springer, 2022) Wang, Anle; Müser, Martin H.Adhesion between an elastic body and a smooth, rigid substrate can lead to large tensile stresses between them. However, most macroscopic objects are microscopically rough, which strongly suppresses adhesion. A fierce debate has unfolded recently as to whether local or global parameters determine the crossover between small and large adhesion. Here, we report simulations revealing that the dependence of the pull-off force Fn on the surface energy γ does not only have two regimes of high and low adhesion but up to four regimes. They are related to contacts, which at the moment of rupture consist of (i) the last individual Hertzian-shaped contact, in which is linear in γ, (ii) a last meso-scale, individual patches with super-linear scaling, (iii) many isolated contact patches with extremely strong scaling, and (iv) a dominating largest contact patch, for which the pull-off stress is no longer negligible compared to the maximum, microscopic pull-off stress. Regime (iii) can be seen as a transition domain. It is located near the point where the surface energy is half the elastic energy per unit area in conformal contact. A criterion for the transition between regimes (i) and (ii) appears difficult to grasp. [Figure not available: see fulltext.].