A Data-driven Reduced Order Modeling Approach Applied In Context Of Numerical Analysis And Optimization Of Plastic Profile Extrusion

In course of this work, we examine the process of plastic profile extrusion, where a polymer melt is shaped inside the so-called extrusion die and fixed in its shape by solidification in the downstream calibration unit. More precise, we focus on the development of a data-driven reduced order model (ROM) for the purpose of predicting temperature distributions within the extruded profiles inside the calibration unit. Therein, the ROM functions as a first step to our overall goal of prediction based process control in order to avoid undesired warpage and damages of the final product.Comment: The 8th European Congress on Computational Methods in Applied Sciences and Engineering ECCOMAS Congress, 2022 5-9 June 2022, Oslo, Norwa

Development of an antibody fragment that stabilizes GPCR/G-protein complexes.

Single-particle cryo-electron microscopy (cryo-EM) has recently enabled high-resolution structure determination of numerous biological macromolecular complexes. Despite this progress, the application of high-resolution cryo-EM to G protein coupled receptors (GPCRs) in complex with heterotrimeric G proteins remains challenging, owning to both the relative small size and the limited stability of these assemblies. Here we describe the development of antibody fragments that bind and stabilize GPCR-G protein complexes for the application of high-resolution cryo-EM. One antibody in particular, mAb16, stabilizes GPCR/G-protein complexes by recognizing an interface between Gα and Gβγ subunits in the heterotrimer, and confers resistance to GTPγS-triggered dissociation. The unique recognition mode of this antibody makes it possible to transfer its binding and stabilizing effect to other G-protein subtypes through minimal protein engineering. This antibody fragment is thus a broadly applicable tool for structural studies of GPCR/G-protein complexes

Comparison of the functional properties of trimeric and monomeric CaiT of Escherichia coli

Secondary transporters exist as monomers, dimers or higher state oligomers. The significance of the oligomeric state is only partially understood. Here, the significance of the trimeric state of the L-carnitine/gamma-butyrobetaine antiporter CaiT of Escherichia coli was investigated. Amino acids important for trimer stability were identified and experimentally verified. Among others, CaiT-D288A and -D288R proved to be mostly monomeric in detergent solution and after reconstitution into proteoliposomes, as shown by blue native gel electrophoresis, gel filtration, and determination of intermolecular distances. CaiT-D288A was fully functional with kinetic parameters similar to the trimeric wild-type. Significant differences in amount and stability in the cell membrane between monomeric and trimeric CaiT were not observed. Contrary to trimeric CaiT, addition of substrate had no or only a minor effect on the tryptophan fluorescence of monomeric CaiT. The results suggest that physical contacts between protomers are important for the substrate-induced changes in protein fluorescence and the underlying conformational alterations

The Sodium/Proline Transporter PutP of Helicobacter pylori

Helicobacter pylori is cause of chronic gastritis, duodenal ulcer and gastric carcinoma in humans. L-proline is a preferred energy source of the microaerophilic bacterium. Previous analyses revealed that HpputP and HpputA, the genes that are predicted to play a central role in proline metabolism as they encode for the proline transporter and proline dehydrogenase, respectively, are essential for stomach colonization. Here, the molecular basis of proline transport in H. pylori by HpPutP was investigated experimentally for the first time. Measuring radiolabeled substrate transport in H. pylori and E. coli heterologously expressing HpputP as well as in proteoliposomes reconstituted with HpPutP, we demonstrate that the observed proline transport in H. pylori is mediated by HpPutP. HpPutP is specific and exhibits a high affinity for L-proline. Notably, L-proline transport is exclusively dependent on Na+ as coupling ion, i.e., Na+/L-proline symport, reminiscent to the properties of PutP of E. coli even though H. pylori lives in a more acidic environment. Homology model-based structural comparisons and substitution analyses identified amino acids crucial for function. HpPutP-catalyzed proline uptake was efficiently inhibited by the known proline analogs 3,4-dehydro-D,L-proline and L-azetidine-2-carboxylic acid

Optical Imaging

Optical Coherence Tomography (OCT)We describe the fundamental concept of optical coherence tomography (OCT) and discuss the two main working principles time domain OCT and frequency domain OCT. Then, we review extended functionalities including spectrally and polarization-resolved OCT as well as Doppler-OCT and show concepts for contrast enhancement. Based on these fundamentals, we demonstrate the potential of OCT for small animal imaging on the basis of exemplary studies on retinal imaging and lung imaging.Optoacoustic ImagingThis chapter deals with the fascinating topic of optoacoustic imaging, a recent powerful addition to the arsenal of in vivo functional and molecular small animal imaging. Due to its hybrid nature, involving optical excitation and ultrasonic detection, optoacoustics overcomes the imaging depth limitations of optical microscopy related to light scattering in living tissues while further benefiting from the compelling advantages of optical contrast. To this end, optoacoustic imaging has been shown capable of delivering multiple types of imaging contrast (structural, functional, kinetic, molecular) within a single imaging modality. It can further deliver images with high spatiotemporal resolution that rivals performance of other well-established whole-body imaging modalities. As such, optoacoustics can play a vital role in biomedical research, from early disease detection and monitoring of dynamic phenomena noninvasively to accelerating drug discovery.Optical ProbesThis chapter is devoted to the properties and application of fluorescence dyes as probes for optical imaging. A variety of agents have been described to date, including nontargeting dyes, vascular agents, targeted conjugates, activatable dyes, and sensing probes. The major classes encompass polymethine dyes and xanthenes dyes, both of which are commercially available in broad variations. Addressing the purpose of optical animal imaging, the most relevant parameters to apply such probes are discussed, thereby supporting the reader in choosing reasonable imaging probes and in preparing bioconjugates for his studies

Intrathecal immunoglobulin A and G antibodies to synapsin in a patient with limbic encephalitis

To report on the identification of intrathecally synthesized immunoglobulin A (IgA) and immunoglobulin G (IgG) antibodies to synapsin, a synaptic vesicle-associated protein, in a patient with limbic encephalitis

Influence of Conductive Additives and Binder on the Impedance of Lithium-Ion Battery Electrodes: Effect of Morphology

Most cathode materials for lithium ion batteries exhibit a low electronic conductivity. Hence, a significant amount of conductive graphitic additives are introduced during electrode production. The mechanical stability and electronic connection of the electrode is enhanced by a mixed phase formed by the carbon and binder materials. However, this mixed phase, the carbon binder domain CBD , hinders the transport of lithium ions through the electrolyte pore network. Thus, reducing the performance at higher currents. In this work we combine microstructure resolved simulations with impedance measurements on symmetrical cells to identify the influence of the CBD distribution. Microstructures of NMC622 electrodes are obtained through synchrotron X ray tomography. Resolving the CBD using tomography techniques is challenging. Therefore, three different CBD distributions are incorporated via a structure generator. We present results of microstructure resolved impedance spectroscopy and lithiation simulations, which reproduce the experimental results of impedance spectroscopy and galvanostatic lithiation measurements, thus, providing a link between the spatial CBD distribution, electrode impedance, and half cell performance. The results demonstrate the significance of the CBD distribution and enable predictive simulations for battery design. The accumulation of CBD at contact points between particles is identified as the most likely configuration in the electrodes under consideratio