TY - JOUR A1 - Roelofs, Freek A1 - Blackburn, Lindy A1 - Lindahl, Greg A1 - Doeleman, Sheperd S. A1 - Johnson, Michael D. A1 - Arras, Philipp A1 - Chatterjee, Koushik A1 - Emami, Razieh A1 - Fromm, Christian A1 - Fuentes, Antonio A1 - Knollmüller, Jakob A1 - Kosogorov, Nikita A1 - Müller, Hendrik A1 - Patel, Nimesh A1 - Raymond, Alexander A1 - Tiede, Paul A1 - Traianou, Efthalia A1 - Vega, Justin T1 - The ngEHT analysis challenges JF - Galaxies N2 - The next-generation Event Horizon Telescope (ngEHT) will be a significant enhancement of the Event Horizon Telescope (EHT) array, with ∼10 new antennas and instrumental upgrades of existing antennas. The increased uv-coverage, sensitivity, and frequency coverage allow a wide range of new science opportunities to be explored. The ngEHT Analysis Challenges have been launched to inform the development of the ngEHT array design, science objectives, and analysis pathways. For each challenge, synthetic EHT and ngEHT datasets are generated from theoretical source models and released to the challenge participants, who analyze the datasets using image reconstruction and other methods. The submitted analysis results are evaluated with quantitative metrics. In this work, we report on the first two ngEHT Analysis Challenges. These have focused on static and dynamical models of M87* and Sgr A* and shown that high-quality movies of the extended jet structure of M87* and near-horizon hourly timescale variability of Sgr A* can be reconstructed by the reference ngEHT array in realistic observing conditions using current analysis algorithms. We identify areas where there is still room for improvement of these algorithms and analysis strategies. Other science cases and arrays will be explored in future challenges. KW - very long baseline interferometry KW - black holes KW - active galactic nuclei KW - radio astronomy KW - imaging KW - instrument design KW - telescopes KW - algorithms KW - data analysis Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-304976 SN - 2075-4434 VL - 11 IS - 1 ER - TY - JOUR A1 - Chatterjee, Koushik A1 - Chael, Andrew A1 - Tiede, Paul A1 - Mizuno, Yosuke A1 - Emami, Razieh A1 - Fromm, Christian A1 - Ricarte, Angelo A1 - Blackburn, Lindy A1 - Roelofs, Freek A1 - Johnson, Michael D. A1 - Doeleman, Sheperd S. A1 - Arras, Philipp A1 - Fuentes, Antonio A1 - Knollmüller, Jakob A1 - Kosogorov, Nikita A1 - Lindahl, Greg A1 - Müller, Hendrik A1 - Patel, Nimesh A1 - Raymond, Alexander A1 - Traianou, Efthalia A1 - Vega, Justin T1 - Accretion flow morphology in numerical simulations of black holes from the ngEHT model library: the impact of radiation physics JF - Galaxies N2 - In the past few years, the Event Horizon Telescope (EHT) has provided the first-ever event horizon-scale images of the supermassive black holes (BHs) M87* and Sagittarius A* (Sgr A*). The next-generation EHT project is an extension of the EHT array that promises larger angular resolution and higher sensitivity to the dim, extended flux around the central ring-like structure, possibly connecting the accretion flow and the jet. The ngEHT Analysis Challenges aim to understand the science extractability from synthetic images and movies to inform the ngEHT array design and analysis algorithm development. In this work, we compare the accretion flow structure and dynamics in numerical fluid simulations that specifically target M87* and Sgr A*, and were used to construct the source models in the challenge set. We consider (1) a steady-state axisymmetric radiatively inefficient accretion flow model with a time-dependent shearing hotspot, (2) two time-dependent single fluid general relativistic magnetohydrodynamic (GRMHD) simulations from the H-AMR code, (3) a two-temperature GRMHD simulation from the BHAC code, and (4) a two-temperature radiative GRMHD simulation from the KORAL code. We find that the different models exhibit remarkably similar temporal and spatial properties, except for the electron temperature, since radiative losses substantially cool down electrons near the BH and the jet sheath, signaling the importance of radiative cooling even for slowly accreting BHs such as M87*. We restrict ourselves to standard torus accretion flows, and leave larger explorations of alternate accretion models to future work. KW - black holes KW - general relativity KW - accretion KW - relativistic jets KW - very-long-baseline interferometry Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-304084 SN - 2075-4434 VL - 11 IS - 2 ER - TY - JOUR A1 - Straub, Anton A1 - Brands, Roman A1 - Borgmann, Anna A1 - Vollmer, Andreas A1 - Hohm, Julian A1 - Linz, Christian A1 - Müller-Richter, Urs A1 - Kübler, Alexander C. A1 - Hartmann, Stefan T1 - Free skin grafting to reconstruct donor sites after radial forearm flap harvesting: a prospective study with platelet-rich fibrin (PRF) JF - Journal of Clinical Medicine N2 - Reconstruction of the donor site after radial forearm flap harvesting is a common procedure in maxillofacial plastic surgery. It is normally carried out with split-thickness or full-thickness free skin grafts. Unfortunately, free skin graft transplantation faces wound healing impairments such as necrosis, (partial) graft loss, or tendon exposure. Several studies have investigated methods to reduce these impairments and demonstrated improvements if the wound bed is optimised, for example, through negative-pressure wound therapy or vacuum-assisted closure. However, these methods are device-dependent, expansive, and time-consuming. Therefore, the application of platelet-rich fibrin (PRF) to the wound bed could be a simple, cost-effective, and device-independent method to optimise wound-bed conditions instead. In this study, PRF membranes were applied between the wound bed and skin graft. Results of this study indicate improvements in the PRF versus non-PRF group (93.44% versus 86.96% graft survival, p = 0.0292). PRF applied to the wound bed increases graft survival and reduces impairments. A possible explanation for this is the release of growth factors, which stimulate angiogenesis and fibroblast migration. Furthermore, the solid PRF membranes act as a mechanical barrier (“lubrication” layer) to protect the skin graft from tendon motion. The results of this study support the application of PRF in donor-site reconstruction with free skin grafts. KW - platelet-rich fibrin KW - free skin grafts KW - radial forearm flap KW - donor-site morbidity Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-278854 SN - 2077-0383 VL - 11 IS - 12 ER - TY - JOUR A1 - Fiedler, Mascha O. A1 - Muellenbach, Ralf M. A1 - Rolfes, Caroline A1 - Lotz, Christopher A1 - Nickel, Felix A1 - Müller-Stich, Beat P. A1 - Supady, Alexander A1 - Lepper, Philipp M. A1 - Weigand, Markus A. A1 - Meybohm, Patrick A1 - Kalenka, Armin A1 - Reyher, Christian T1 - Pumpless extracorporeal hemadsorption technique (pEHAT): a proof-of-concept animal study JF - Journal of Clinical Medicine N2 - Background: Extracorporeal hemadsorption eliminates proinflammatory mediators in critically ill patients with hyperinflammation. The use of a pumpless extracorporeal hemadsorption technique allows its early usage prior to organ failure and the need for an additional medical device. In our animal model, we investigated the feasibility of pumpless extracorporeal hemadsorption over a wide range of mean arterial pressures (MAP). Methods: An arteriovenous shunt between the femoral artery and femoral vein was established in eight pigs. The hemadsorption devices were inserted into the shunt circulation; four pigs received CytoSorb\(^®\) and four Oxiris\(^®\) hemadsorbers. Extracorporeal blood flow was measured in a range between mean arterial pressures of 45–85 mmHg. Mean arterial pressures were preset using intravenous infusions of noradrenaline, urapidil, or increased sedatives. Results: Extracorporeal blood flows remained well above the minimum flows recommended by the manufacturers throughout all MAP steps for both devices. Linear regression resulted in CytoSorb\(^®\) blood flow [mL/min] = 4.226 × MAP [mmHg] − 3.496 (R-square 0.8133) and Oxiris\(^®\) blood flow [mL/min] = 3.267 × MAP [mmHg] + 57.63 (R-square 0.8708), respectively. Conclusion: Arteriovenous pumpless extracorporeal hemadsorption resulted in sufficient blood flows through both the CytoSorb\(^®\) and Oxiris\(^®\) devices over a wide range of mean arterial blood pressures and is likely an intriguing therapeutic option in the early phase of septic shock or hyperinflammatory syndromes. KW - blood purification KW - extracorporeal hemadsorption KW - cytokines KW - adsorption KW - animal model KW - immunosorbents KW - septic shock KW - endotoxin KW - extracorporeal techniques in hemadsorption therapy KW - arteriovenous extracorporeal hemadsorption technique Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-297347 SN - 2077-0383 VL - 11 IS - 22 ER - TY - JOUR A1 - Opolka, Alexander A1 - Müller, Dominik A1 - Fella, Christian A1 - Balles, Andreas A1 - Mohr, Jürgen A1 - Last, Arndt T1 - Multi-lens array full-field X-ray microscopy JF - Applied Sciences N2 - X-ray full-field microscopy at laboratory sources for photon energies above 10 keV suffers from either long exposure times or low resolution. The photon flux is mainly limited by the objectives used, having a limited numerical aperture NA. We show that this can be overcome by making use of the cone-beam illumination of laboratory sources by imaging the same field of view (FoV) several times under slightly different angles using an array of X-ray lenses. Using this technique, the exposure time can be reduced drastically without any loss in terms of resolution. A proof-of-principle is given using an existing laboratory metal-jet source at the 9.25 keV Ga K\(_α\)-line and compared to a ray-tracing simulation of the setup. KW - X-ray microscopy KW - full-field microscopy KW - compound refractive X-ray lenses KW - CRLs Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-244974 SN - 2076-3417 VL - 11 IS - 16 ER - TY - JOUR A1 - Boschert, Verena A1 - Klenk, Nicola A1 - Abt, Alexander A1 - Raman, Sudha Janaki A1 - Fischer, Markus A1 - Brands, Roman C. A1 - Seher, Axel A1 - Linz, Christian A1 - Müller-Richter, Urs D. A. A1 - Bischler, Thorsten A1 - Hartmann, Stefan T1 - The influence of Met receptor level on HGF-induced glycolytic reprogramming in head and neck squamous cell carcinoma JF - International Journal of Molecular Sciences N2 - Head and neck squamous cell carcinoma (HNSCC) is known to overexpress a variety of receptor tyrosine kinases, such as the HGF receptor Met. Like other malignancies, HNSCC involves a mutual interaction between the tumor cells and surrounding tissues and cells. We hypothesized that activation of HGF/Met signaling in HNSCC influences glucose metabolism and therefore substantially changes the tumor microenvironment. To determine the effect of HGF, we submitted three established HNSCC cell lines to mRNA sequencing. Dynamic changes in glucose metabolism were measured in real time by an extracellular flux analyzer. As expected, the cell lines exhibited different levels of Met and responded differently to HGF stimulation. As confirmed by mRNA sequencing, the level of Met expression was associated with the number of upregulated HGF-dependent genes. Overall, Met stimulation by HGF leads to increased glycolysis, presumably mediated by higher expression of three key enzymes of glycolysis. These effects appear to be stronger in Met\(^{high}\)-expressing HNSCC cells. Collectively, our data support the hypothesized role of HGF/Met signaling in metabolic reprogramming of HNSCC. KW - HNSCC KW - head and neck cancer KW - HGF KW - Met KW - cancer metabolism Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-235995 SN - 1422-0067 VL - 21 IS - 2 ER - TY - JOUR A1 - Weselek, Grit A1 - Keiner, Silke A1 - Fauser, Mareike A1 - Wagenführ, Lisa A1 - Müller, Julia A1 - Kaltschmidt, Barbara A1 - Brandt, Moritz D. A1 - Gerlach, Manfred A1 - Redecker, Christoph A1 - Hermann, Andreas A1 - Storch, Alexander T1 - Norepinephrine is a negative regulator of the adult periventricular neural stem cell niche JF - Stem Cells N2 - The limited proliferative capacity of neuroprogenitor cells (NPCs) within the periventricular germinal niches (PGNs) located caudal of the subventricular zone (SVZ) of the lateral ventricles together with their high proliferation capacity after isolation strongly implicates cell‐extrinsic humoral factors restricting NPC proliferation in the hypothalamic and midbrain PGNs. We comparatively examined the effects of norepinephrine (NE) as an endogenous candidate regulator of PGN neurogenesis in the SVZ as well as the periventricular hypothalamus and the periaqueductal midbrain. Histological and neurochemical analyses revealed that the pattern of NE innervation of the adult PGNs is inversely associated with their in vivo NPC proliferation capacity with low NE levels coupled to high NPC proliferation in the SVZ but high NE levels coupled to low NPC proliferation in hypothalamic and midbrain PGNs. Intraventricular infusion of NE decreased NPC proliferation and neurogenesis in the SVZ‐olfactory bulb system, while pharmacological NE inhibition increased NPC proliferation and early neurogenesis events in the caudal PGNs. Neurotoxic ablation of NE neurons using the Dsp4‐fluoxetine protocol confirmed its inhibitory effects on NPC proliferation. Contrarily, NE depletion largely impairs NPC proliferation within the hippocampus in the same animals. Our data indicate that norepinephrine has opposite effects on the two fundamental neurogenic niches of the adult brain with norepinephrine being a negative regulator of adult periventricular neurogenesis. This knowledge might ultimately lead to new therapeutic approaches to influence neurogenesis in hypothalamus‐related metabolic diseases or to stimulate endogenous regenerative potential in neurodegenerative processes such as Parkinson's disease. KW - adult neurogenesis KW - hippocampus KW - noradrenaline KW - norepinephrine KW - olfactory bulb neurogenesis KW - subventricular zone Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218250 VL - 38 IS - 9 SP - 1188 EP - 1201 ER - TY - JOUR A1 - Hennessen, Fabienne A1 - Miethke, Marcus A1 - Zaburannyi, Nestor A1 - Loose, Maria A1 - Lukežič, Tadeja A1 - Bernecker, Steffen A1 - Hüttel, Stephan A1 - Jansen, Rolf A1 - Schmiedel, Judith A1 - Fritzenwanker, Moritz A1 - Imirzalioglu, Can A1 - Vogel, Jörg A1 - Westermann, Alexander J. A1 - Hesterkamp, Thomas A1 - Stadler, Marc A1 - Wagenlehner, Florian A1 - Petković, Hrvoje A1 - Herrmann, Jennifer A1 - Müller, Rolf T1 - Amidochelocardin overcomes resistance mechanisms exerted on tetracyclines and natural chelocardin JF - Antibiotics N2 - The reassessment of known but neglected natural compounds is a vital strategy for providing novel lead structures urgently needed to overcome antimicrobial resistance. Scaffolds with resistance-breaking properties represent the most promising candidates for a successful translation into future therapeutics. Our study focuses on chelocardin, a member of the atypical tetracyclines, and its bioengineered derivative amidochelocardin, both showing broad-spectrum antibacterial activity within the ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) panel. Further lead development of chelocardins requires extensive biological and chemical profiling to achieve favorable pharmaceutical properties and efficacy. This study shows that both molecules possess resistance-breaking properties enabling the escape from most common tetracycline resistance mechanisms. Further, we show that these compounds are potent candidates for treatment of urinary tract infections due to their in vitro activity against a large panel of multidrug-resistant uropathogenic clinical isolates. In addition, the mechanism of resistance to natural chelocardin was identified as relying on efflux processes, both in the chelocardin producer Amycolatopsis sulphurea and in the pathogen Klebsiella pneumoniae. Resistance development in Klebsiella led primarily to mutations in ramR, causing increased expression of the acrAB-tolC efflux pump. Most importantly, amidochelocardin overcomes this resistance mechanism, revealing not only the improved activity profile but also superior resistance-breaking properties of this novel antibacterial compound. KW - chelocardins KW - atypical tetracyclines KW - broad-spectrum antibiotics KW - clinical isolates KW - uropathogens KW - urinary tract infection (UTI) KW - resistance-breaking properties KW - mechanism of resistance KW - AcrAB-TolC efflux pump Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-213149 SN - 2079-6382 VL - 9 IS - 9 ER - TY - JOUR A1 - Scheurer, Mario Joachim Johannes A1 - Brands, Roman Camillus A1 - El-Mesery, Mohamed A1 - Hartmann, Stefan A1 - Müller-Richter, Urs Dietmar Achim A1 - Kübler, Alexander Christian A1 - Seher, Axel T1 - The selection of NFκB inhibitors to block inflammation and induce sensitisation to FasL-induced apoptosis in HNSCC cell lines is critical for their use as a prospective cancer therapy JF - International Journal of Molecular Science N2 - Inflammation is a central aspect of tumour biology and can contribute significantly to both the origination and progression of tumours. The NFκB pathway is one of the most important signal transduction pathways in inflammation and is, therefore, an excellent target for cancer therapy. In this work, we examined the influence of four NFκB inhibitors — Cortisol, MLN4924, QNZ and TPCA1 — on proliferation, inflammation and sensitisation to apoptosis mediated by the death ligand FasL in the HNSCC cell lines PCI1, PCI9, PCI13, PCI52 and SCC25 and in the human dermal keratinocyte cell line HaCaT. We found that the selection of the inhibitor is critical to ensure that cells do not respond by inducing counteracting activities in the context of cancer therapy, e.g., the extreme IL-8 induction mediated by MLN4924 or FasL resistance mediated by Cortisol. However, TPCA1 was qualified by this in vitro study as an excellent therapeutic mediator in HNSCC by four positive qualities: (1) proliferation was inhibited at low μM-range concentrations; (2) TNFα-induced IL-8 secretion was blocked; (3) HNSCC cells were sensitized to TNFα-induced cell death; and (4) FasL-mediated apoptosis was not disrupted. KW - HNSCC KW - NFκB KW - inhibitor KW - TPCA1 KW - apoptosis KW - inflammation KW - TNFα KW - FasL Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-201524 SN - 1422-0067 VL - 20 IS - 6 ER - TY - JOUR A1 - Hattori, Yohei A1 - Michail, Evripidis A1 - Schmiedel, Alexander A1 - Moos, Michael A1 - Holzapfel, Marco A1 - Krummenacher, Ivo A1 - Braunschweig, Holger A1 - Müller, Ulrich A1 - Pflaum, Jens A1 - Lambert, Christoph T1 - Luminescent Mono-, Di-, and Tri-radicals: Bridging Polychlorinated Triarylmethyl Radicals by Triarylamines and Triarylboranes JF - Chemistry - A European Journal N2 - Up to three polychlorinated pyridyldiphenylmethyl radicals bridged by a triphenylamine carrying electron withdrawing (CN), neutral (Me), or donating (OMe) groups were synthesized and analogous radicals bridged by tris(2,6‐dimethylphenyl)borane were prepared for comparison. All compounds were as stable as common closed‐shell organic compounds and showed significant fluorescence upon excitation. Electronic, magnetic, absorption, and emission properties were examined in detail, and experimental results were interpreted using DFT calculations. Oxidation potentials, absorption and emission energies could be tuned depending on the electron density of the bridges. The triphenylamine bridges mediated intramolecular weak antiferromagnetic interactions between the radical spins, and the energy difference between the high spin and low spin states was determined by temperature dependent ESR spectroscopy and DFT calculations. The fluorescent properties of all radicals were examined in detail and revealed no difference for high and low spin states which facilitates application of these dyes in two‐photon absorption spectroscopy and OLED devices. KW - density functional calculations KW - fluorescence KW - NIR OLED KW - radical KW - two-photon absorption Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-208162 VL - 25 IS - 68 ER -