TY - JOUR A1 - Zonneveld, Ben J. M. T1 - The DNA weights per nucleus (genome size) of more than 2350 species of the Flora of The Netherlands, of which 1370 are new to science, including the pattern of their DNA peaks JF - Forum Geobotanicum N2 - Besides external characteristics and reading a piece of DNA (barcode), the DNA weight per nucleus (genome size) via flow cytometry is a key value to detect species and hybrids and determine ploidy. In addition, the DNA weight appears to be related to various properties, such as the size of the cell and the nucleus, the duration of mitosis and meiosis and the generation time. Sometimes it is even possible to distinguish between groups or sections, which can lead to new classification of the genera. The variation in DNA weight is also useful to analyze biodiversity, genome evolution and relationships between related taxa. Moreover, it is important to know how large a genome is before one determines the base sequence of the DNA of a plant. Flow cytometry is also important for understanding fundamental processes in plants such as growth and development and recognizing chimeras. In the literature, DNA weight measurements are usually limited to one genus and often only locally (Siljak et al. 2010; Bai et al. 2012). In this study, however, it was decided to investigate all vascular plants from one country. This can also contribute to the protection of rare plants. This study is the first flora in the world whose weight of DNA per nucleus and peak patterns has been determined. More than 6400 plants, representing more than 2350 (sub)species (more than 90%) have been collected, thanks to the help of almost 100 volunteers of Floristisch Onderzoek Nederland (Floron). Multiple specimens of many species have therefore been measured, preferably from different populations, in some cases more than fifty. For 1370 species, these values were not previously published. Moreover, a good number of the remaining 45% are new for The Netherlands. In principle, each species has a fixed weight of DNA per nucleus. It has also been found that, especially between the genera, there are strong differences in the number of peaks that determine the DNA weight, from one to five peaks. This indicates that in a plant or organ there are sometimes nuclei with multiples of its standard DNA weight (multiple ploidy levels). It is impossible to show graphs of more than 2350 species. Therefore, we have chosen to show the peak pattern in a new way in a short formula. Within most genera there are clear differences in the DNA weights per nucleus between the species, in some other genera the DNA weight is hardly variable. Based on about twenty genera that were previously measured completely in most cases (‘t Hart et al. 2003: Veldkamp and Zonneveld 2011; Soes et al. 2012; Dirkse et al. 2014, 2015; Verloove et al. 2017; Zonneveld [et al.] 2000−2018), it can be noted that even if all species of a genus have the same number of chromosomes, there can still be a difference of up to three times in the weight of the DNA. Therefore, a twice larger DNA weight does not have to indicate four sets of chromosomes. Finally, this research has also found clues to examine further the current taxonomy of a number of species or genera. KW - DNA weight KW - Pflanzen KW - genome KW - flora KW - Netherlands Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-189724 UR - http://www.forum-geobotanicum.net/articles/vol_8-2018/zonneveld_flora-of-the-netherlands/zonneveld_flora-of-the-netherlands.pdf SN - 1867-9315 VL - 8 ER - TY - THES A1 - Zilker, Markus T1 - The stability of finished pharmaceutical products and drug substances beyond their labeled expiry dates T1 - Die Stabilität von Fertigarzneimitteln und Wirkstoffen nach Ablauf des Verfalldatums N2 - Upon approval of a drug, the stability of the API and the FPP has to be studied intensively because it determines the shelf-life. If a drug is found to be stable, the expiry date is arbitrary set to five years at the maximum, if a drug tends to undergo degradation, the expiry date is set shorter. The drug product must comply with predefined specifications in accordance with the ICH guidelines Q6A and Q6B during its entire market life. The content of the active substance is required to be within a specification of 95–105% of its labeled claim until expiry corresponding to the ICH guideline Q1A(R2). However, there is little or scattered literature information addressing the stability of drug products beyond their expiry dates. The objective of this thesis was to study and assess the long-term stability of a collection involving numerous pure drug substances and ampoules manufactured in the 20th century. The content and the impurity profile were examined by means of appropriate analytical methods, mainly using liquid chromatography. The results were compared to data being available in the literature. Assessing the stability regarding the dosage form and the affiliation of the drug class was conducted. The experimental studies comprise the examination of 50 drug substances manufactured 20–30 years ago and 14 long expired ampoules which were older than 40 years in the time of analysis, exceeding many times the maximum shelf life of five years. For investigation of the solid drug substances, pharmacopoeial methods were applied as far as possible. Indeed, results of the study showed that 44 tested substances still complied with the specification of the Ph. Eur. with regard to the content and impurity profile, even after more than two decades of storage. For analysis of the injection solutions, HPLC-UV and HPLC-ESI/MS techniques were applied, commonly based on liquid chromatography methods of the Ph. Eur. for determination of related substances. Each method was further validated for its application to ensure accurate API quantification corresponding to ICH Q2(R1). Quite a few ampoules were identified to show surprisingly high stability. In spite of their age of 53–72 years, APIs such as caffeine, etilefrine, synephrine, metamizole sodium, furosemide, and sodium salicylate complied with the specified content that is valid nowadays, respectively. Nevertheless, typical degradation reaction, e.g. hydrolysis, oxidation, or isomerization, was observed in all remaining ampoules. Various degrees of hydrolysis were revealed for scopolamine, procaine, and adenosine triphosphate, the contents were decreased to 71%, 70%, and 15% of the declared concentrations, respectively. In the epinephrine and dipyridamole ampoules, oxidative degradation has been occurred, finding respective API contents of more or less 70%. For dihydroergotamine, excessive decomposition by epimerization was observed, resulting in an API content of 21% and degradation by isomerization was found in lobeline, still containing 64% of the labeled claim. In conclusion, supported by the data of the present studies and the literature, defining and authorizing a longer shelf-life may be applicable to numerous pharmaceuticals which should be considered by pharmaceutical manufacturers and regulatory authorities, if justified based on stability studies. A general extension of the shelf-lives of drug products and the abolishment or extension of the maximum shelf-life limit of five years would prevent disposing of still potent medications and save a lot of money to the entire health care system. N2 - Bei der Zulassung eines Arzneimittels muss die Stabilität sowohl des Wirkstoffes als auch des Fertigarzneimittels umfassend untersucht werden, da dies für die Festlegung der Haltbarkeit wesentlich ist. Wenn sich herausstellt, dass ein Arzneimittel stabil ist, wird das Verfallsdatum auf höchstens fünf Jahre festgelegt. Neigt ein Arzneimittel zum Abbau, so wird ein kürzeres Verfallsdatum gewählt. Das Arzneimittel muss innerhalb der Haltbarkeitsfrist definierten Spezifikationen entsprechen, welche in den ICH-Richtlinien Q6A und Q6B festgelegt sind. Dabei muss insbesondere der Wirkstoff-Gehalt des Arzneimittels gemäß der ICH-Richtlinie Q1A(R2) innerhalb der Spezifikation von 95–105 % der deklarierten Konzentration liegen. In der Literatur gibt es jedoch wenige Informationen darüber, wie stabil Arzneimittel lange nach Ablauf des Verfallsdatums sind. Das Ziel dieser Arbeit war es, die Stabilität zahlreicher Feststoffe und Ampullen, die aus einer Altarzneimittel-Sammlung stammten und während des 20. Jahrhunderts hergestellt wurden, zu untersuchen und zu bewerten. Der Gehalt und das Verunreinigungsprofil wurden mittels geeigneter instrumenteller Analyseverfahren bestimmt, wobei hauptsächlich flüssigchromatographische Methoden zur Anwendung kamen. Die Untersuchungsergebnisse wurden mit Literaturdaten verglichen und es wurde eine Beurteilung der Stabilität in Abhängigkeit von der Darreichungsform und der Zugehörigkeit zu einer Arzneistoffklasse vorgenommen. Die experimentellen Studien umfassten die Untersuchung von 50 Feststoffen, die vor 20 bis 30 Jahren hergestellt worden waren, und 14 Alt-Ampullen, die ein Alter von mindestens 40 Jahre aufwiesen und damit die maximale Haltbarkeit von fünf Jahren um ein Vielfaches überschritten hatten. Zur Untersuchung der Feststoffe wurden meist Arzneibuchmethoden verwendet. Die Ergebnisse zeigten, dass 44 geprüfte Substanzen auch nach mehr als zwei Jahrzehnten hinsichtlich ihres Gehalts und Verunreinigungsprofils den jeweiligen Spezifikationen des Europäischen Arzneibuchs entsprachen. Zur Analyse der Alt Ampullen wurden HPLC-UV- und HPLC-ESI/MS-Techniken eingesetzt. Diese basierten häufig auf Arzneibuch-Methoden zur Prüfung auf verwandte Substanzen. Für die Gehaltsbestimmungen wurden entsprechend der ICH-Richtlinie Q2(R1) die erforderlichen Parameter validiert. Einige Ampullen zeigten eine überraschend hohe Stabilität des Wirkstoffs, trotz ihres Alters von 53 bis 72 Jahren. Dabei entsprachen die Wirkstoffe Koffein, Etilefrin, Synephrin, Metamizol Natrium, Furosemid und Natriumsalicylat dem heute gültigen Spezifikationsbereich von 95–105 %. Nichtsdestoweniger wurden bei einigen Ampullen typische Abbaureaktionen wie Hydrolyse, Oxidation oder Isomerisierung festgestellt. Die Hydrolyse der Arzneistoffe Scopolamin, Procain und Adenosintriphosphat führte zu verringerten Gehalten von 71 %, 70 % bzw. 15 % der jeweiligen gekennzeichneten Wirkstoffkonzentration. Die Epinephrin- und Dipyridamol-Injektionslösungen waren von oxidativem Abbau betroffen. Der Wirkstoffgehalt dieser Ampullen lag jeweils bei ca. 70 %. In der Dihydroergotamin Ampulle trat eine massive Epimerisierung auf, wobei ein Gehalt von 21 % bestimmt wurde. Aufgrund der Isomerisierung des Arzneistoffes Lobelin reduzierte sich der Wirkstoffgehalt auf 64 %. Als Schlussfolgerung der experimentellen Studien und der verfügbaren Daten aus der Literatur sollten die pharmazeutischen Unternehmer und die Aufsichtsbehörden erwägen, die Haltbarkeitsdauer für zahlreiche Arzneimittel zu verlängern, wenn dies basierend auf Stabilitätsuntersuchungen gerechtfertigt ist. Eine generelle Ausweitung der Verwendbarkeit von Arzneimitteln sowie die Abschaffung oder Erweiterung der maximalen Haltbarkeitsdauer von fünf Jahren würde die Entsorgung noch wirksamer Medikamente verhindern und dem Gesundheitssystem viel Geld einsparen. KW - Stabilität KW - Fertigarzneimittel KW - Wirkstoff KW - Chromatographie KW - Chemical stability KW - Shelf-life KW - Expiry date Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-180695 ER - TY - JOUR A1 - Zhou, Xiang A1 - Wuchter, Patrick A1 - Egerer, Gerlinde A1 - Kriegsmann, Mark A1 - Mataityte, Aiste A1 - Koelsche, Christian A1 - Witzens-Harig, Mathias A1 - Kriegsmann, Katharina T1 - Role of virological serum markers in patients with both hepatitis B virus infection and diffuse large B-cell lymphoma JF - European Journal of Haematology N2 - Background Causality between hepatitis B virus (HBV) infection and diffuse large B-cell lymphoma (DLBCL) was reported in various studies. However, the implication of different virological serum markers of HBV infection in patients with both HBV infection and DLBCL is not fully understood. The aim of this study was to investigate the impact of HBV markers on overall survival (OS) and progression-free survival (PFS) in patients with both HBV infection and DLBCL. Methods In this study, patients (n = 40) diagnosed with both HBV infection and DLBCL were identified between 2000 and 2017. Six patients with hepatitis C virus (HCV) and/or human immunodeficiency virus (HIV) co-infection were excluded from this study. We retrospectively analyzed patients’ demographic characteristics, treatment, and the prognostic impact of different HBV markers at first diagnosis of DLBCL (HBsAg, anti-HBs, HBeAg, anti-HBe, and HBV-DNA) on OS and PFS. Results The majority of patients (n = 21, 62%) had advanced disease stage (III/IV) at diagnosis. In the first-line therapy, 24 patients (70%) were treated with R-CHOP regimen (rituximab, cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisolone). HBeAg positive patients had a trend toward inferior OS and PFS compared with HBeAg negative patients. Anti-HBe positive patients had a statistically significant better OS and PFS compared with anti-HBe negative group (both P < .0001). Viremia with HBV-DNA ≥ 2 × 107 IU/L had a significant negative impact on OS and PFS (both P < .0001). Conclusion High activity of viral replication is associated with a poor survival outcome of patients with both HBV infection and DLBCL. KW - hepatitis B virus KW - diffuse large B-cell lymphoma KW - prognosis Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-258442 VL - 103 IS - 4 ER - TY - JOUR A1 - Zhang, Yonghong A1 - Zheng, Lanlan A1 - Zheng, Yan A1 - Zhou, Chao A1 - Huang, Ping A1 - Xiao, Xiao A1 - Zhao, Yongheng A1 - Hao, Xincai A1 - Hu, Zhubing A1 - Chen, Qinhua A1 - Li, Hongliang A1 - Wang, Xuanbin A1 - Fukushima, Kenji A1 - Wang, Guodong A1 - Li, Chen T1 - Assembly and Annotation of a Draft Genome of the Medicinal Plant Polygonum cuspidatum JF - Frontiers in Plant Science N2 - Polygonum cuspidatum (Japanese knotweed, also known as Huzhang in Chinese), a plant that produces bioactive components such as stilbenes and quinones, has long been recognized as important in traditional Chinese herbal medicine. To better understand the biological features of this plant and to gain genetic insight into the biosynthesis of its natural products, we assembled a draft genome of P. cuspidatum using Illumina sequencing technology. The draft genome is ca. 2.56 Gb long, with 71.54% of the genome annotated as transposable elements. Integrated gene prediction suggested that the P. cuspidatum genome encodes 55,075 functional genes, including 6,776 gene families that are conserved in the five eudicot species examined and 2,386 that are unique to P. cuspidatum. Among the functional genes identified, 4,753 are predicted to encode transcription factors. We traced the gene duplication history of P. cuspidatum and determined that it has undergone two whole-genome duplication events about 65 and 6.6 million years ago. Roots are considered the primary medicinal tissue, and transcriptome analysis identified 2,173 genes that were expressed at higher levels in roots compared to aboveground tissues. Detailed phylogenetic analysis demonstrated expansion of the gene family encoding stilbene synthase and chalcone synthase enzymes in the phenylpropanoid metabolic pathway, which is associated with the biosynthesis of resveratrol, a pharmacologically important stilbene. Analysis of the draft genome identified 7 abscisic acid and water deficit stress-induced protein-coding genes and 14 cysteine-rich transmembrane module genes predicted to be involved in stress responses. The draft de novo genome assembly produced in this study represents a valuable resource for the molecular characterization of medicinal compounds in P. cuspidatum, the improvement of this important medicinal plant, and the exploration of its abiotic stress resistance. KW - genome assembly KW - resveratrol biosynthesis KW - whole-genome duplication KW - medicinal plant KW - stress tolerance KW - Polygonum cuspidatum Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-189279 SN - 1664-462X VL - 10 ER - TY - JOUR A1 - Zhang, Fangyuan A1 - Michail, Evripidis A1 - Saal, Fridolin A1 - Krause, Ana-Maria A1 - Ravat, Prince T1 - Stereospecific Synthesis and Photophysical Properties of Propeller-Shaped C\(_{90}\)H\(_{48}\) PAH JF - Chemistry - A European Journal N2 - Herein, we have synthesized an enantiomerically pure propeller‐shaped PAH, C\(_{90}\)H\(_{48}\), possessing three [7]helicene and three [5]helicene subunits. This compound can be obtained in gram quantities in a straightforward manner. The photophysical and chiroptical properties were investigated using UV/Vis absorption and emission, optical rotation and circular dichroism spectroscopy, supported by DFT calculations. The nonlinear optical properties were investigated by two‐photon absorption measurements using linearly and circularly polarized light. The extremely twisted structure and packing of the homochiral compound were investigated by single‐crystal X‐ray diffraction analysis. KW - chirality KW - enantiomers KW - helicenes KW - polycyclic aromatic hydrocarbons KW - stereospecific sythesis Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-208682 VL - 25 IS - 71 ER - TY - JOUR A1 - Zetzl, Teresa A1 - Schuler, Michael A1 - Renner, Agnes A1 - Jentschke, Elisabeth A1 - van Oorschot, Birgitt T1 - Yoga intervention and reminder e-mails for reducing cancer-related fatigue - a study protocol of a randomized controlled trial JF - BMC Psychology N2 - Background Almost 90% of cancer patients suffer from symptoms of fatigue during treatment. Supporting treatments are increasingly used to alleviate the burden of fatigue. This study examines the short-term and long-term effects of yoga on fatigue and the effect of weekly reminder e-mails on exercise frequency and fatigue symptoms. Methods The aim of the first part of the study will evaluate the effectiveness of yoga for cancer patients with mixed diagnoses reporting fatigue. We will randomly allocate 128 patients to an intervention group (N = 64) receiving yoga and a wait-list control group (N = 64) receiving yoga 9 weeks later. The yoga therapy will be performed in weekly sessions of 60 min each for 8 weeks. The primary outcome will be self-reported fatigue symptoms. In the second part of the study, the effectiveness of reminder e-mails with regard to the exercise frequency and self-reported fatigue symptoms will be evaluated. A randomized allocated group of the participants (“email”) receives weekly reminder e-mails, the other group does not. Data will be assessed using questionnaires the beginning and after yoga therapy as well as after 6  months. Discussion Support of patients suffering from fatigue is an important goal in cancer patients care. If yoga therapy will reduce fatigue, this type of therapy may be introduced into routine practice. If the reminder e-mails prove to be helpful, new offers for patients may also develop from this. KW - Cancer KW - Fatigue KW - Yoga KW - Reminder e-mails KW - Supportive therapy Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-202268 VL - 7 ER - TY - THES A1 - Zapf, Michael T1 - Oxidische Perovskite mit Hoher Massenzahl Z: Dünnfilmdeposition und Spektroskopische Untersuchungen T1 - High-Z Perovskite Oxides: Thin Film Deposition and Spectroscopic Investigations N2 - Perovskite oxides are a very versatile material class with a large variety of outstanding physical properties. A subgroup of these compounds particularly tempting to investigate are oxides involving high-\(Z\) elements, where spin-orbit coupling is expected to give rise to new intriguing phases and potential application-relevant functionalities. This thesis deals with the preparation and characterization of two representatives of high-\(Z\) oxide sample systems based on KTaO\(_3\) and BaBiO\(_3\). KTaO\(_3\) is a band insulator with an electronic valence configuration of Ta 5\(d\)\(^0\) . It is shown that by pulsed laser deposition of a disordered LaAlO\(_3\) film on the KTaO\(_3\)(001) surface, through the creation of oxygen vacancies, a Ta 5\(d\)\(^{0+\(\delta\)}\) state is obtained in the upmost crystal layers of the substrate. In consequence a quasi two dimensional electron system (q2DES) with large spin-orbit coupling emerges at the heterointerface. Measurements of the Hall effect establish sheet carrier densities in the range of 0.1-1.2 10\(^{14}\) cm\(^2\), which can be controlled by the applied oxygen background pressure during deposition and the LaAlO\(_3\) film thickness. When compared to the prototypical oxide q2DESs based on SrTiO\(_3\) crystals, the investigated system exhibits exceptionally large carrier mobilities of up to 30 cm\(^2\)/Vs (7000 cm\(^2\)/Vs) at room temperature (below 10 K). Through a depth profiling by photoemission spectra of the Ta 4\(f\) core level it is shown that the majority of the Ta 5\(d\)\(^0\) charge carriers, consisting of mobile and localized electrons, is situated within 4 nm from the interface at low temperatures. Furthermore, the momentum-resolved electronic structure of the q2DES \(buried\) underneath the LaAlO\(_3\) film is probed by means of hard X-ray angle-resolved photoelectron spectroscopy. It is inferred that, due to a strong confinement potential of the electrons, the band structure of the system is altered compared to \(n\)-doped bulk KTO. Despite the constraint of the electron movement along one direction, the Fermi surface exhibits a clear three dimensional momentum dependence, which is related to a depth extension of the conduction channels of at least 1 nm. The second material, BaBiO\(_3\), is a charge-ordered insulator, which has recently been predicted to emerge as a large-gap topological insulator upon \(n\)-doping. This study reports on the thin film growth of pristine BaBiO\(_3\) on Nb:SrTiO\(_3\)(001) substrates by means of pulsed laser deposition. The mechanism is identified that facilitates the development of epitaxial order in the heterostructure despite the presence of an extraordinary large lattice mismatch of 12 %. At the heterointerface, a structurally modified layer of about 1.7 nm thickness is formed that gradually relieves the in-plane strain and serves as the foundation of a relaxed BBO film. The thereupon formed lattice orders laterally in registry with the substrate with the orientation BaBiO\(_3\)(001)||SrTiO\(_3\)(001) by so-called domain matching, where 8 to 9 BaBiO\(_3\) unit cells align with 9 to 10 unit cells of the substrate. Through the optimization of the deposition conditions in regard to the cation stoichiometry and the structural lattice quality, BaBiO\(_3\) thin films with bulk-like electronic properties are obtained, as is inferred from a comparison of valence band spectra with density functional theory calculations. Finally, a spectroscopic survey of BaBiO\(_3\) samples of various thicknesses resolves that a recently discovered film thickness-controlled phase transition in BaBiO\(_3\) thin films can be traced back to the structural and concurrent stoichiometric modifications occuring in the initially formed lattice on top of the SrTiO\(_3\) substrate rather than being purely driven by the smaller spatial extent of the BBO lattice. N2 - Komplexe Metalloxide mit Perowskitstruktur sind bekannt für ihre große Vielfalt einzigartiger physikalischer Eigenschaften. Eine interessante Untergruppe dieser Materialien sind Verbindungen von Elementen mit hoher Ordnungszahl \(Z\), in denen neue, durch Spin-Bahn Kopplung getriebene Phasen und anwendungsrelevante Funktionalitäten erwartet werden. Diese Arbeit handelt von der Präparation und Charakterisierung zweier Probensysteme, die auf eben solchen Materialien mit hoher \(Z\) basieren. KTaO\(_3\) ist ein Bandisolator, der im Grundzustand eine Ta 5\(d\)\(^0\) Valenz besitzt. Durch gepulste Laserdeposition von ungeordnetem LaAlO\(_3\) auf der KTaO\(_3\)(001) Oberfläche, werden die obersten Schichten des Substratkristalls durch die Erzeugung von Sauerstofffehlstellen dotiert. Es bildet sich ein quasi zweidimensionales metallisches Elektronensystem (q2DES) an der Grenzfläche der Heterostruktur aus. Messungen des Hall-Effekts ergeben Schichtladungsträgerdichten im Bereich von 0.1-1.2 10\(^{14}\) cm\(^2\), welche durch Anpassung des Sauerstoffhintergrunddrucks während der Deposition bzw. durch die Dicke der abgeschiedenen LaAlO\(_3\) Schicht beeinflusst werden können. Mit Werten von 30 cm\(^2\)/Vs (7000 cm\(^2\)/Vs) bei Raumtemperatur (unter 10 K), besitzt das q2DES in LaAlO\(_3\)/KTaO\(_3\) im Vergleich zu ähnlichen Elektronensystemen in SrTiO\(_3\) bemerkenswert große Ladungsträgerbeweglichkeiten. Aus dem Tiefenprofil des Photoemissionspektrums des Ta 4\(f\) Rumpfniveaus ergibt sich, dass sich der Großteil der Ta 5\(d\) Ladungsträger, bestehend aus mobilen und lokalisierten Elektronen, innerhalb einer Schicht von 4 nm Dicke befindet. Die Vermessung der elektronischen Bandstruktur des vergrabenen q2DES mit Hilfe winkelaufgelöster Photoelektronenspektroskopie mit harter Röntgenstrahlung zeigt, dass das Elektronensystem, vermutlich wegen des starken Potentialgradients an der Grenzfläche, eine modifizierte elektronische Struktur gegenüber n-dotiertem Bulk-KTaO\(_3\) aufweist. Trotz der Einschränkung der Bewegung der Elektronen entlang einer Richtung, besitzt die Fermifläche des Systems eine dreidimensionale Struktur, woarus auf eine Tiefenausdehnung der metallischen Zustände von mindestens 1 nm geschlossen werden kann. Undotiertes BaBiO\(_3\) ist durch die Ausbildung einer Ladungsordnung isolierend. Unter Elektronendotierung gilt das Material als Kandidat für einen oxidischen topologischen Isolator. In dieser Studie wird die Deposition von BaBiO\(_3\) auf Nb:SrTiO\(_3\)(001) Substraten untersucht. Dabei wird der Mechanismus identifiziert, der epitaktisches Wachstum von BaBiO\(_3\), trotz einer Gitterfehlanpassung von 12 %, ermöglicht: Eine 1.7 nm dicke Lage mit abweichender Kristallstruktur an der Grenzfläche entkoppelt das Filmgitter vom Substrat, sodass darüber vollständig relaxiertes BaBiO\(_3\) aufwachsen kann. Dieses weist eine epitaktische Orientierung von BaBiO\(_3\)(001)||SrTiO\(_3\)(001) auf, die durch die Ausbildung von lateralen Gitterdomänen, bei denen 8 bzw. 9 BaBiO\(_3\) auf 9 bzw. 10 SrTiO\(_3\) Einheitszellen ausgerichtet sind, gewährleistet wird. Die Stoichiometrie und die strukturelle Qualität der BaBiO\(_3\) Filme werden durch eine systematische Anpassung der Depositionsbedingungen optimiert. Die Valenzbandstruktur der Proben stimmt gut mit Rechnungen der Dichtefunktionaltheorie überein, was darauf hindeutet, dass die Filme hinsichtlich der elektronischen Eigenschaften mit BaBiO\(_3\) Einkristallen vergleichbar sind. Eine abschließende Untersuchung eines schichtdickenabhängigen Phasenübergangs in BaBiO\(_3\) Dünnfilmen, von dem kürzlich in der Literatur berichtet wurde, belegt, dass dieser nicht allein auf die Ausdehnung des Kristallgitters, sondern auch auf strukturelle und stoichiometrische Modifikationen der untersten Filmlagen zurückzuführen ist. KW - Perowskit KW - Röntgen-Photoelektronenspektroskopie KW - Pulsed laser deposition KW - Übergangsmetalloxide KW - KTaO3 KW - BaBiO3 KW - Oxide Heterostructure KW - Interface Conductivity KW - oxidische Heterostruktur KW - Grenzflächenleitfähigkeit KW - Winkelaufgelöste Photoemission mit harten Röntgenstrahlen KW - Hard X-ray Angle Resolved Photoemission KW - High-Z Oxides KW - HARPES Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-185370 ER - TY - THES A1 - Yu, Sung-Huan T1 - Development and application of computational tools for RNA-Seq based transcriptome annotations T1 - Entwicklung und Anwendung bioinformatischer Werkzeuge für RNA-Seq-basierte Transkriptom-Annotationen N2 - In order to understand the regulation of gene expression in organisms, precise genome annotation is essential. In recent years, RNA-Seq has become a potent method for generating and improving genome annotations. However, this Approach is time consuming and often inconsistently performed when done manually. In particular, the discovery of non-coding RNAs benefits strongly from the application of RNA-Seq data but requires significant amounts of expert knowledge and is labor-intensive. As a part of my doctoral study, I developed a modular tool called ANNOgesic that can detect numerous transcribed genomic features, including non-coding RNAs, based on RNA-Seq data in a precise and automatic fashion with a focus on bacterial and achaeal species. The software performs numerous analyses and generates several visualizations. It can generate annotations of high-Resolution that are hard to produce using traditional annotation tools that are based only on genome sequences. ANNOgesic can detect numerous novel genomic Features like UTR-derived small non-coding RNAs for which no other tool has been developed before. ANNOgesic is available under an open source license (ISCL) at https://github.com/Sung-Huan/ANNOgesic. My doctoral work not only includes the development of ANNOgesic but also its application to annotate the transcriptome of Staphylococcus aureus HG003 - a strain which has been a insightful model in infection biology. Despite its potential as a model, a complete genome sequence and annotations have been lacking for HG003. In order to fill this gap, the annotations of this strain, including sRNAs and their functions, were generated using ANNOgesic by analyzing differential RNA-Seq data from 14 different samples (two media conditions with seven time points), as well as RNA-Seq data generated after transcript fragmentation. ANNOgesic was also applied to annotate several bacterial and archaeal genomes, and as part of this its high performance was demonstrated. In summary, ANNOgesic is a powerful computational tool for RNA-Seq based annotations and has been successfully applied to several species. N2 - Exakte Genomannotationen sind essentiell für das Verständnis Genexpressionsregulation in verschiedenen Organismen. In den letzten Jahren entwickelte sich RNA-Seq zu einer äußerst wirksamen Methode, um solche Genomannotationen zu erstellen und zu verbessern. Allerdings ist das Erstellen von Genomannotationen bei manueller Durchführung noch immer ein zeitaufwändiger und inkonsistenter Prozess. Die Verwendung von RNA-Seq-Daten begünstigt besonders die Identifizierung von nichtkodierenden RNAs, was allerdings arbeitsintensiv ist und fundiertes Expertenwissen erfordert. Ein Teil meiner Promotion bestand aus der Entwicklung eines modularen Tools namens ANNOgesic, das basierend auf RNA-Seq-Daten in der Lage ist, eine Vielzahl von Genombestandteilen, einschließlich nicht-kodierender RNAs, automatisch und präzise zu ermitteln. Das Hauptaugenmerk lag dabei auf der Anwendbarkeit für bakterielle und archaeale Genome. Die Software führt eine Vielzahl von Analysen durch und stellt die verschiedenen Ergebnisse grafisch dar. Sie generiert hochpräzise Annotationen, die nicht unter Verwendung herkömmlicher Annotations-Tools auf Basis von Genomsequenzen erzeugt werden könnten. Es kann eine Vielzahl neuer Genombestandteile, wie kleine nicht-kodierende RNAs in UTRs, ermitteln, welche von bisherigen Programme nicht vorhergesagt werden können. ANNOgesic ist unter einer Open-Source-Lizenz (ISCL) auf https://github.com/Sung-Huan/ANNOgesic verfügbar. Meine Forschungsarbeit beinhaltet nicht nur die Entwicklung von ANNOgesic, sondern auch dessen Anwendung um das Transkriptom des Staphylococcus aureus-Stamms HG003 zu annotieren. Dieser ist einem Derivat von S. aureus NCTC8325 - ein Stamm, Dear ein bedeutendes Modell in der Infektionsbiologie darstellt. Zum Beispiel wurde er für die Untersuchung von Antibiotikaresistenzen genutzt, da er anfällig für alle bekannten Antibiotika ist. Der Elternstamm NCTC8325 besitzt zwei Mutationen im regulatorischen Genen (rsbU und tcaR), die Veränderungen der Virulenz zur Folge haben und die in Stamm HG003 auf die Wildtypsequenz zurückmutiert wurden. Dadurch besitzt S. aureus HG003 das vollständige, ursprüngliche Regulationsnetzwerk und stellt deshalb ein besseres Modell zur Untersuchung von sowohl Virulenz als auch Antibiotikaresistenz dar. Trotz seines Modellcharakters fehlten für HG003 bisher eine vollständige Genomsequenz und deren Annotationen. Um diese Lücke zu schließen habe ich als Teil meiner Promotion mit Hilfe von ANNOgesic Annotationen für diesen Stamm, einschließlich sRNAs und ihrer Funktionen, generiert. Dafür habe ich Differential RNA-Seq-Daten von 14 verschiedenen Proben (zwei Mediumsbedingungen mit sieben Zeitpunkten) sowie RNA-Seq-Daten, die von fragmentierten Transkripten generiert wurden, analysiert. Neben S. aureus HG003 wurde ANNOgesic auf eine Vielzahl von Bakterien- und Archaeengenome angewendet und dabei wurde eine hohe Performanz demonstriert. Zusammenfassend kann gesagt werden, dass ANNOgesic ein mächtiges bioinformatisches Werkzeug für die RNA-Seq-basierte Annotationen ist und für verschiedene Spezies erfolgreich angewandt wurde. KW - RNA-Seq KW - Genome Annotation KW - small RNA KW - Genom KW - Annotation KW - Small RNA KW - Bioinformatik Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176468 ER - TY - JOUR A1 - Youssif, Khayrya A. A1 - Haggag, Eman G. A1 - Elshamy, Ali M. A1 - Rabeh, Mohamed A. A1 - Gabr, Nagwan M. A1 - Seleem, Amany A1 - Salem, M. Alaraby A1 - Hussein, Ahmed S. A1 - Krischke, Markus A1 - Mueller, Martin J. A1 - Ramadan Abdelmohsen, Usama T1 - Anti-Alzheimer potential, metabolomic profiling and molecular docking of green synthesized silver nanoparticles of Lampranthus coccineus and Malephora lutea aqueous extracts JF - PLoS ONE N2 - The green synthesis of silver nanoparticles (SNPs) using plant extracts is an eco-friendly method. It is a single step and offers several advantages such as time reducing, cost-effective and environmental non-toxic. Silver nanoparticles are a type of Noble metal nanoparticles and it has tremendous applications in the field of diagnostics, therapeutics, antimicrobial activity, anticancer and neurodegenerative diseases. In the present work, the aqueous extracts of aerial parts of Lampranthus coccineus and Malephora lutea F. Aizoaceae were successfully used for the synthesis of silver nanoparticles. The formation of silver nanoparticles was early detected by a color change from pale yellow to reddish-brown color and was further confirmed by transmission electron microscope (TEM), UV–visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), and energy-dispersive X-ray diffraction (EDX). The TEM analysis of showed spherical nanoparticles with a mean size between 12.86 nm and 28.19 nm and the UV- visible spectroscopy showed λ\(_{max}\) of 417 nm, which confirms the presence of nanoparticles. The neuroprotective potential of SNPs was evaluated by assessing the antioxidant and cholinesterase inhibitory activity. Metabolomic profiling was performed on methanolic extracts of L. coccineus and M. lutea and resulted in the identification of 12 compounds, then docking was performed to investigate the possible interaction between the identified compounds and human acetylcholinesterase, butyrylcholinesterase, and glutathione transferase receptor, which are associated with the progress of Alzheimer’s disease. Overall our SNPs highlighted its promising potential in terms of anticholinesterase and antioxidant activity as plant-based anti-Alzheimer drug and against oxidative stress. KW - Nanoparticles KW - Silver KW - Alzheimer's disease KW - Glutathione KW - Antioxidants KW - Serine proteases KW - Brain diseases KW - Metabolomics Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-202696 VL - 14 IS - 11 ER - TY - JOUR A1 - Yang, Manli A1 - Rajeeve, Karthika A1 - Rudel, Thomas A1 - Dandekar, Thomas T1 - Comprehensive Flux Modeling of Chlamydia trachomatis Proteome and qRT-PCR Data Indicate Biphasic Metabolic Differences Between Elementary Bodies and Reticulate Bodies During Infection JF - Frontiers in Microbiology N2 - Metabolic adaptation to the host cell is important for obligate intracellular pathogens such as Chlamydia trachomatis (Ct). Here we infer the flux differences for Ct from proteome and qRT-PCR data by comprehensive pathway modeling. We compare the comparatively inert infectious elementary body (EB) and the active replicative reticulate body (RB) systematically using a genome-scale metabolic model with 321 metabolites and 277 reactions. This did yield 84 extreme pathways based on a published proteomics dataset at three different time points of infection. Validation of predictions was done by quantitative RT-PCR of enzyme mRNA expression at three time points. Ct’s major active pathways are glycolysis, gluconeogenesis, glycerol-phospholipid (GPL) biosynthesis (support from host acetyl-CoA) and pentose phosphate pathway (PPP), while its incomplete TCA and fatty acid biosynthesis are less active. The modeled metabolic pathways are much more active in RB than in EB. Our in silico model suggests that EB and RB utilize folate to generate NAD(P)H using independent pathways. The only low metabolic flux inferred for EB involves mainly carbohydrate metabolism. RB utilizes energy -rich compounds to generate ATP in nucleic acid metabolism. Validation data for the modeling include proteomics experiments (model basis) as well as qRT-PCR confirmation of selected metabolic enzyme mRNA expression differences. The metabolic modeling is made fully available here. Its detailed insights and models on Ct metabolic adaptations during infection are a useful modeling basis for future studies. KW - metabolic modeling KW - metabolic flux KW - infection biology KW - elementary body KW - reticulate body KW - Chlamydia trachomatis Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-189434 SN - 1664-302X VL - 10 IS - 2350 ER - TY - JOUR A1 - Wörsdörfer, Philipp A1 - Dalda, Nahide A1 - Kern, Anna A1 - Krüger, Sarah A1 - Wagner, Nicole A1 - Kwok, Chee Keong A1 - Henke, Erik A1 - Ergün, Süleyman T1 - Generation of complex human organoid models including vascular networks by incorporation of mesodermal progenitor cells JF - Scientific Reports N2 - Organoids derived from human pluripotent stem cells are interesting models to study mechanisms of morphogenesis and promising platforms for disease modeling and drug screening. However, they mostly remain incomplete as they lack stroma, tissue resident immune cells and in particular vasculature, which create important niches during development and disease. We propose, that the directed incorporation of mesodermal progenitor cells (MPCs) into organoids will overcome the aforementioned limitations. In order to demonstrate the feasibility of the method, we generated complex human tumor as well as neural organoids. We show that the formed blood vessels display a hierarchic organization and mural cells are assembled into the vessel wall. Moreover, we demonstrate a typical blood vessel ultrastructure including endothelial cell-cell junctions, a basement membrane as well as luminal caveolae and microvesicles. We observe a high plasticity in the endothelial network, which expands, while the organoids grow and is responsive to anti-angiogenic compounds and pro-angiogenic conditions such as hypoxia. We show that vessels within tumor organoids connect to host vessels following transplantation. Remarkably, MPCs also deliver Iba1\(^+\) cells that infiltrate the neural tissue in a microglia-like manner. KW - Developmental biology KW - Stem cells Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-202681 VL - 9 ER - TY - JOUR A1 - Wutzler, Alexander A1 - Krogias, Christos A1 - Grau, Anna A1 - Veltkamp, Roland A1 - Heuschmann, Peter U. A1 - Haeusler, Karl Georg T1 - Stroke prevention in patients with acute ischemic stroke and atrial fibrillation in Germany - a cross sectional survey JF - BMC Neurology N2 - Background Atrial fibrillation (AF) is present in 15–20% of patients with acute ischemic stroke. Oral anticoagulation reduces the risk of AF-related recurrent stroke but clinical guideline recommendations are rather vague regarding its use in the acute phase of stroke. We aimed to assess the current clinical practice of medical stroke prevention in AF patients during the acute phase of ischemic stroke. Methods In April 2017, a standardized anonymous questionnaire was sent to clinical leads of all 298 certified stroke units in Germany. Results Overall, 154 stroke unit leads participated (response rate 52%). Anticoagulation in the acute phase of stroke is considered feasible in more than 90% of AF patients with ischemic stroke. Clinicians assume that about two thirds of all AF patients (range 20–100%) are discharged on oral anticoagulation. According to local preferences, acetylsalicylic acid is given orally in the majority of patients with delayed initiation of oral anticoagulation. A non-vitamin K-dependent oral anticoagulant (NOAC) is more often prescribed than a vitamin K-dependent oral anticoagulant (VKA). VKA is more often chosen in patients with previous VKA intake than in VKA naive patients. In the minority of patients, stroke unit leads discuss the prescription of a specific oral anticoagulant with the treating general practitioner. Adherence to medical stroke prevention after hospital discharge is not assessed on a regular basis in any patient by the majority of participating stroke centers. Conclusions Early secondary stroke prevention in AF patients in German stroke units is based on OAC use but prescription modalities vary in clinical practice. KW - Ischemic stroke KW - Secondary stroke prevention KW - Atrial fibrillation KW - Survey KW - Oral anticoagulation KW - Stroke unit Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-201078 VL - 19 ER - TY - JOUR A1 - Wu, Hao A1 - Reimann, Sabine A1 - Siddiqui, Sophiya A1 - Haag, Rainer A1 - Siegmund, Britta A1 - Dernedde, Jens A1 - Glauben, Rainer T1 - dPGS Regulates the Phenotype of Macrophages via Metabolic Switching JF - Macromolecular Bioscience N2 - The synthetic compound dendritic polyglycerol sulfate (dPGS) is a pleiotropic acting molecule but shows a high binding affinity to immunological active molecules as L‐/P‐selectin or complement proteins leading to well described anti‐inflammatory properties in various mouse models. In order to make a comprehensive evaluation of the direct effect on the innate immune system, macrophage polarization is analyzed in the presence of dPGS on a phenotypic but also metabolic level. dPGS administered macrophages show a significant increase of MCP1 production paralleled by a reduction of IL‐10 secretion. Metabolic analysis reveals that dPGS could potently enhance the glycolysis and mitochondrial respiration in M0 macrophages as well as decrease the mitochondrial respiration of M2 macrophages. In summary the data indicate that dPGS polarizes macrophages into a pro‐inflammatory phenotype in a metabolic pathway‐dependent manner. KW - infection KW - macrophage polarization KW - MCP1 KW - metabolic switch KW - polyglycerol sulfates Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-212711 VL - 19 IS - 12 ER - TY - THES A1 - Wu, Fang T1 - Adding new functions to insulin-like growth factor-I (IGF-I) via genetic codon expansion T1 - Hinzufügen neuer Funktionen zu Insulin-like Growth Factor-I (IGF-I) durch genetische Codon-Erweiterung N2 - Insulin-like growth factor-I (IGF-I) is a 70-amino acid polypeptide with a molecular weight of approximately 7.6 kDa acting as an anabolic effector. It is essential for tissue growth and remodeling. Clinically, it is used for the treatment of growth disorders and has been proposed for various other applications including musculoskeletal diseases. Unlike insulin, IGF-I is complexed to at least six high-affinity binding proteins (IGFBPs) exerting homeostatic effects by modulating IGF-I availability to its receptor (IGF-IR) on most cells in the body as well as changing the distribution of the growth factor within the organism.1-3 Short half-lived IGF-I have been the driving forces for the design of localized IGF-I depot systems or protein modification with enhanced pharmacokinetic properties. In this thesis, we endeavor to present a versatile biologic into which galenical properties were engineered through chemical synthesis, e.g., by site-specific coupling of biomaterials or complex composites to IGF-I. For that, we redesigned the therapeutic via genetic codon expansion resulting in an alkyne introduced IGF-I, thereby becoming a substrate for biorthogonal click chemistries yielding a site-specific decoration. In this approach, an orthogonal pyrrolysine tRNA synthetase (PylRS)/tRNAPyl CUA pair was employed to direct the co-translational incorporation of an unnatural amino acid—¬propargyl-L-lysine (plk)—bearing a clickable alkyne functional handle into IGF-I in response to the amber stop codon (UAG) introduced into the defined position in the gene of interest. We summarized the systematic optimization of upstream and downstream process alike with the ultimate goal to increase the yield of plk modified IGF-I therapeutic, from the construction of gene fusions resulting in (i) Trx-plk-IGF-I fusion variants, (ii) naturally occurring pro-IGF-I protein (IGF-I + Ea peptide) (plk-IGF-I Ea), over the subsequent bacterial cultivation and protein extraction to the final chromatographic purification. The opportunities and hurdles of all of the above strategies were discussed. Evidence was provided that the wild-type IGF-I yields were pure by exploiting the advantages of the pHisTrx expression vector system in concert with a thrombin enzyme with its highly specific proteolytic digestion site and multiple-chromatography steps. The alkyne functionality was successfully introduced into IGF-I by amber codon suppression. The proper folding of plk-IGF-I Ea was assessed by WST-1 proliferation assay and the detection of phosphorylated AKT in MG-63 cell lysate. The purity of plk-IGF-I Ea was monitored with RP-HPLC and SDS-PAGE analysis. This work also showed site-specific coupling an alkyne in plk-IGF-I Ea by copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) with potent activities in vitro. The site-specific immobilization of plk-IGF-I Ea to the model carrier (i.e., agarose beads) resulted in enhanced cell proliferation and adhesion surrounding the IGF-I-presenting particles. Cell proliferation and differentiation were enhanced in the accessibility of IGF-I decorated beads, reflecting the multivalence on cellular performance. Next, we aimed at effectively showing the disease environment by co-delivery of fibroblast growth factor 2 (FGF2) and IGF-I, deploying localized matrix metalloproteinases (MMPs) upregulation as a surrogate marker driving the response of the drug delivery system. For this purpose, we genetically engineered FGF2 variant containing an (S)-2-amino-6-(((2-azidoethoxy)carbonyl)amino)hexanoic acid incorporated at its N-terminus, followed by an MMPs-cleavable linker (PCL) and FGF2 sequence, thereby allowing site-directed, specific decoration of the resultant azide-PCL-FGF2 with the previously mentioned plk-IGF-I Ea to generate defined protein-protein conjugates with a PCL in between. The click reaction between plk-IGF-I Ea and azide-PCL-FGF2 was systematically optimized to increase the yield of IGF-FGF conjugates, including reaction temperature, incubation duration, the addition of anionic detergent, and different ratios of the participating biopharmaceutics. The challenge here was that CuAAC reaction components or conditions might oxidize free cysteines of azide-PCL-FGF2 and future work needs to present the extent of activity retention after conjugation. Furthermore, our study provides potential options for dual-labeling of IGF-I either by the introduction of unnatural amino acids within two distinct positions of the protein of interest for parallel “double-click” labeling of the resultant plk-IGF-I Ea-plk or by using a combination of enzymatic-catalyzed and CuAAC bioorthogonal coupling strategies for sequentially dual-labeling of plk-IGF-I Ea. In conclusion, genetic code expansion in combination with click-chemistry provides the fundament for novel IGF-I analogs allowing unprecedented site specificity for decoration. Considerable progress towards IGF-I based therapies with enhanced pharmacological properties was made by demonstrating the feasibility of the expression of plk incorporated IGF-I using E. coli and retained activity of unconjugated and conjugated IGF-I variant. Dual-labeling of IGF-I provides further insights into the functional requirements of IGF-I. Still, further investigation warrants to develop precise IGF-I therapy through unmatched temporal and spatial regulation of the pleiotropic IGF-I. N2 - Insulin-like growth factor-I (IGF-I) ist ein 70 Aminosäuren langes Polypeptid mit einem Molekuargewicht von 7,5 kDa, dass als anaboler Effektor wirkt und dadurch eine essentielle Rolle in Gewebewachstum und -umbau spielt. Klinisch wird IGF-I für die Behandlung von Wachstumsstörungen verwendet und ist für weitere Anwendungen wie muskuloskelettale Erkrankungen von Interesse. Im Gegensatz zu Insulin wird IGF-I von mindestens sechs hochaffinen Bindungsproteinen (IGFBPs) komplexiert, die homöostatisch regulierend wirken, indem sie die Verfügbarkeit von IGF-I zu seinem Rezeptor (IGF-IR) auf vielen Zellen modulieren und ebenso die Verteilung des Wachstumsfaktors im Körper steuern. Aufgrund der kurzen Halbwertszeit von IGF-I wurde die Entwicklung von lokalen IGF-I Depot-Systemen und von auf Proteinebene modifizierten IGF-I-Varianten mit verbesserten pharmakokinetischen Eigenschaften vorangetrieben. In der vorliegenden Arbeit sind wir bestrebt ein vielseitiges Biopharmazeutikum zu präsentieren, das hinsichtlich seiner galenischen Eigenschaften optimiert wurde, z. B. durch chemische Modifikation, wie ortsspezifische Kopplung von IGF-I an Biomaterialien oder komplexe Verbundstoffe. Für diesen Zweck wurde das Therapeutikum neu entworfen und über die Erweiterung des genetischen Codes eine Alkin-Funktionalität eingefügt. Durch dieses Alkin wird IGF-I zugänglich für die Modifizierung mit bio-orthogonaler, ortsspezifischer „Click-Chemie“. In diesem Ansatz wird ein orthogonales Pyrrolysin tRNA-Synthase (PylRS)/tRNAPyl-CUA – Paar verwendet, um den co-translationalen Einbau einer unnatürlichen Aminosäure — Propargyl-L-lysine (Plk) —, die eine Alkin-Funktionalität für Click-Reaktionen enthält, an Stelle des Amber-Stop-Codons (UAG) im entsprechenden Gen, im IGF-I-Protein zu gewährleisten. Die systematische Optimierung von Up- und Downstream-Prozessen, mit dem Ziel die Ausbeute von Plk-modifiziertem IGF-I-Biopharmazeutikum zu erhöhen, wurden zusammengefasst: von der Konstruktion von Genfusionen, die in (i) einer Trx-plk-IGF-I Fusionsvariant und (ii) natürlich vorkommendem pro-IGF-I Protein (IGF-I + Ea peptide) (Plk-IGF-I Ea) resultierten, über die folgende Expression in Bakterien und Proteinextraktion, bis hin zur finalen chromatographischen Reinigung des Biopharmazeutikums. Die Möglichkeiten und Schwierigkeiten aller oben genannten Strategien wurden diskutiert. Es wurde gezeigt, dass die Wildtyp-IGF-I-Ausbeuten durch den Einsatz des vorteilhaften pHisTrx-Expressionsvektor-Systems zusammen mit dem Enzym Thrombin und seiner hochspezifischen proteolytischen Spaltstelle und mehrfacher chromatographischer Aufreinigung einen hohen Reinheitsgrad aufwiesen. Die Alkin-Funktionalität wurde erfolgreich durch Unterdrückung des Amber-Codons in IGF-I eingeführt. Die richtige Faltung von Plk-IGF-I Ea wurde durch den WST-1 Proliferationsassay und den Nachweis von phosphorylierten Akt in MG-63-Zelllysat nachgewiesen. Die Reinheit von Plk-IGF-I Ea wurde durch RP-HPLC- und SDS-PAGE-Analyse überwacht. In dieser Arbeit konnte auch gezeigt werden, dass die ortspezifische Kopplung von Alkinen an Plk-IGF-I Ea durch Kupfer(I)-katalysierte Azid-Alkin Zykloaddition (CuAAC) in einem Produkt mit hoher in vitro Aktivität resultiert. Die ortspezifische Immobilisierung von Plk-IGF-I Ea an einem Modell-Trägersystem (hier: Agarosepartikel) führte zu einer verbesserten Zellproliferation und Zelladhäsion in der Umgebung der IGF-I-präsentierenden Partikel. Der vielfältige Einfluss von IGF-I auf Zellen wird durch die verbesserte Zellproliferation und -differenzierung durch die Verfügbarkeit von IGF-I präsentierenden Partikeln widergespiegelt. Als Nächstes setzten wir uns zum Ziel den Krankheitseinfluss durch die gleichzeitige Anwendung von Fibroblast-Wachstumsfaktor 2 (FGF2) und IGF-I zu zeigen, indem wir uns der lokalen Hochregulierung von Matrixmetalloproteinasen (MMPS) als Surrogat-Krankheitsmarker bedienten, der die Antwort des Drug Delivery-Systems auslöst. Zu diesem Zweck wurde eine FGF2-Variante genetisch modifiziert, sodass sie am N-Terminus eine (S)-2-amino-6-(((2-azidoethoxy)carbonyl)amino)Hexansäure trägt - gefolgt von einen durch MMPs spaltbaren Verbindungsstück (PCL) und der FGF2 Sequenz - und dadurch die gezielte, spezifische Konjugation des resultierenden Azid-PCL-FGF2 mit dem vorher erwähnten Plk-IGF-I Ea ermöglicht, um definierte Protein-Protein-Konjugate, die mit einem PCL verbunden sind, zu erzeugen. Die Click-Reaktion zwischen Plk-IGF-I Ea und Azid-PCL-FGF2 wurde zur Erhöhung der IGF-FGF Ausbeute systematisch optimiert, indem die Parameter Temperatur, Inkubationsdauer, Zugabe von anionischem Tensid und verschiedene Eduktverhältnisse untersucht wurden. Es gilt zu bedenken, dass die in der CuAAC Reaktion eingesetzten Komponenten oder Reaktionsbedingungen freie Cysteinreste von Azid-PCL-FGF2 oxidieren können und es in Zukunft gilt, die verbleibende Aktivität nach Proteinkonjugation zu bestimmen. Des Weiteren zeigen unsere Untersuchungen potentielle Möglichkeiten für duale Konjugation von IGF-I entweder durch die Einführung einer unnatürlichen Aminosäure an zwei verschiedenen Positionen innerhalb des Proteins (Plk-IGF-I Ea-Plk) für parallele „Doppel-Click“-Konjugation oder durch die Kombination bioorthogonaler Kopplungsreaktionen - einer enzymkatalysierten Reaktion und CuAAC - für sequentielles duales Verknüpfen von Plk-IGF-I Ea. Schlussendlich stellt die Erweiterung des genetischen Codes in Kombination mit Click-Chemie eine Grundlage für neue IGF-I-Analoga dar, die eine noch nie dagewesene Ortsspezifität für Konjugationen besitzen. Ein entscheidender Fortschritt hin zu IGF-I basierten Therapeutika mit verbesserten pharmakologischen Eigenschaften wurde durch die Expression, Reinigung und Konjugation von bioaktivem IGF-I mit Plk sowie konjugierten IGF-I Varianten erreicht. Duales Modifizieren von IGF-I erlaubt weitere Einblicke in die funktionalen Anforderungen an IGF-I. Dennoch sind weitere Untersuchungen nötig, um eine gezielte IGF-I Therapie trotz der unterschiedlichen zeitlichen und räumlichen Regulierung des pleiotropen IGF-I zu ermöglichen. KW - Insulin-like growth factor-I KW - genetic codon expansion KW - site-specific protein modification KW - Insulin-like Growth Factor I KW - Codon Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-175330 ER - TY - JOUR A1 - Woodcock, B. A. A1 - Garratt, M. P. D. A1 - Powney, G. D. A1 - Shaw, R. F. A1 - Osborne, J. L. A1 - Soroka, J. A1 - Lindström, S. A. M. A1 - Stanley, D. A1 - Ouvrard, P. A1 - Edwards, M. E. A1 - Jauker, F. A1 - McCracken, M. E. A1 - Zou, Y. A1 - Potts, S. G. A1 - Rundlöf, M. A1 - Noriega, J. A. A1 - Greenop, A. A1 - Smith, H. G. A1 - Bommarco, R. A1 - van der Werf, W. A1 - Stout, J. C. A1 - Steffan-Dewenter, I. A1 - Morandin, L. A1 - Bullock, J. M. A1 - Pywell, R. F. T1 - Meta-analysis reveals that pollinator functional diversity and abundance enhance crop pollination and yield JF - Nature Communications N2 - How insects promote crop pollination remains poorly understood in terms of the contribution of functional trait differences between species. We used meta-analyses to test for correlations between community abundance, species richness and functional trait metrics with oilseed rape yield, a globally important crop. While overall abundance is consistently important in predicting yield, functional divergence between species traits also showed a positive correlation. This result supports the complementarity hypothesis that pollination function is maintained by non-overlapping trait distributions. In artificially constructed communities (mesocosms), species richness is positively correlated with yield, although this effect is not seen under field conditions. As traits of the dominant species do not predict yield above that attributed to the effect of abundance alone, we find no evidence in support of the mass ratio hypothesis. Management practices increasing not just pollinator abundance, but also functional divergence, could benefit oilseed rape agriculture. KW - agroecology KW - agriculture KW - ecosystem services KW - environmental sciences Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-233787 VL - 10 ER - TY - JOUR A1 - Wobser, Marion A1 - Weber, Alexandra A1 - Glunz, Amelie A1 - Tauch, Saskia A1 - Seitz, Kristina A1 - Butelmann, Tobias A1 - Hesbacher, Sonja A1 - Goebeler, Matthias A1 - Bartz, René A1 - Kohlhof, Hella A1 - Schrama, David A1 - Houben, Roland T1 - Elucidating the mechanism of action of domatinostat (4SC-202) in cutaneous T cell lymphoma cells JF - Journal of Hematology & Oncology N2 - Background Targeting epigenetic modifiers is effective in cutaneous T cell lymphoma (CTCL). However, there is a need for further improvement of this therapeutic approach. Here, we compared the mode of action of romidepsin (FK228), an established class I histone deacetylase inhibitor, and domatinostat (4SC-202), a novel inhibitor of class I HDACs, which has been reported to also target the lysine-specific histone demethylase 1A (LSD1). Methods We performed MTS assays and flow cytometric analyses of propidium iodide or annexin V-stained cells to assess drug impact on cellular proliferation, cell cycle distribution, and survival. Histone acetylation and methylation as well as caspase activation was analyzed by immunoblot. Gene expression analysis was performed using NanosString technology. Knockdown and knockout of LSD1 was achieved with shRNA and CRISPR/Cas9, respectively, while the CRISPR/Cas9 synergistic activation mediator system was used to induce expression of endogenous HDACs and LSD1. Furthermore, time-lapse fluorescence microscopy and an in vitro tubulin polymerization assay were applied. Results While FK228 as well as 4SC-202 potently induced cell death in six different CTCL cell lines, only in the case of 4SC-202 death was preceded by an accumulation of cells in the G2/M phase of the cell cycle. Surprisingly, apoptosis and accumulation of cells with double DNA content occurred already at 4SC-202 concentrations hardly affecting histone acetylation and methylation, and provoking significantly less changes in gene expression compared to biologically equivalent doses of FK228. Indeed, we provide evidence that the 4SC-202-induced G2/M arrest in CTCL cells is independent of de novo transcription. Furthermore, neither enforced expression of HDAC1 nor knockdown or knockout of LSD1 affected the 4SC-202-induced effects. Since time-lapse microscopy revealed that 4SC-202 could affect mitotic spindle formation, we performed an in vitro tubulin polymerization assay revealing that 4SC-202 can directly inhibit microtubule formation. Conclusions We demonstrate that 4SC-202, a drug currently tested in clinical trials, effectively inhibits growth of CTCL cells. The anti-cancer cell activity of 4SC-202 is however not limited to LSD1-inhibition, modulation of histone modifications, and consecutive alteration of gene expression. Indeed, the compound is also a potent microtubule-destabilizing agent. KW - Cutaneous lymphoma KW - Epigenetic regulation KW - Histone deacetylase KW - HDAC KW - Lysine-specific methylase KW - LSD1 KW - Tubulin Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-200703 VL - 12 ER - TY - THES A1 - Wistlich, Laura T1 - NCO-sP(EO-stat-PO) as functional additive for biomaterials’ development T1 - NCO-sP(EO-stat-PO) als funktionale Additive für die Entwicklung von Biomaterialien N2 - The aim of this thesis was the application of the functional prepolymer NCO-sP(EO-stat-PO) for the development of new biomaterials. First, the influence of the star-shaped polymers on the mechanical properties of biocements and bone adhesives was investigated. 3-armed star-shaped macromers were used as an additive for a mineral bone cement, and the influence on the mechanical properties was studied. Additionally, a previously developed bone adhesive was examined regarding cytocompatibility. The second topic was the examination of novel functionalization steps which were performed on the surface of electrospun fibers modified with NCO-sP(EO-stat-PO). This established method of functionalizing electrospun meshes was advanced regarding the modification with proteins which was then demonstrated in a biological application. Two different kinds of antibodies were immobilized on the fiber surface in a consecutive manner and the influence of these proteins on the cell behavior was investigated. The final topic involved the quantification of surface-bound peptide sequences. By functionalization of the peptides with the UV-reactive molecule 2-mercaptopyridine it was possible to quantify this compound via UV measurements by cleavage of disulfide bridges and indirectly draw conclusions about the number of immobilized peptides. In the field of mineral biocements and bone adhesives, NCO-sP(EO-stat-PO) was able to influence the setting behavior and mechanical performance of mineral bone cements based on calcium phosphate chemistry. The addition of NCO-sP(EO-stat-PO) resulted in a pseudo-ductile fracture behavior due to the formation of a hydrogel network in the cement, which was then mineralized by nanosized hydroxyapatite crystals following cement setting. Accordingly, a commercially available aluminum silicate cement from civil engineering could be modified. In addition, it could be shown that the use of NCO-sP(EO-stat-PO) is beneficial for adjusting specific material properties of bone adhesives. Here, the crosslinking behavior of the prepolymer in an aqueous medium was exploited to form an interpenetrating network (IPN) together with a photochemically curing poly(ethylene glycol) dimethacrylate (PEGDMA) matrix. This could be used for the development of a bone adhesive with an improved adhesion to bone in a wet environment. The developed bone adhesive was further investigated in terms of possible influences of the initiator systems. In addition, the material system was tested for cytocompatibility by using different cell lines. Moreover, the preparation of electrospun fiber meshes via solution electrospinning consisting of poly(lactide-co-glycolide) (PLGA) as a backbone polymer and NCO-sP(EO-stat-PO) as functional additive is an established method for the application of the meshes as a replacement of the native extracellular matrix (ECM). In general, these fibers reveal diameters in the nanometer range, are protein and cell repellent due to the hydrophilic properties of the prepolymer and show a specific biofunctionalization by immobilization of peptide sequences. Here, the isocyanate groups presented on the fiber surface after electrospinning were used to carry out various functionalization steps, while retaining the properties of protein and cell repellency. The modification of the electrospun fibers involved the immobilization of analogs or antagonists of tumor necrosis factor (TNF) and the indirect detection of these by interaction with a light-producing enzyme. Here, a multimodal modification of the fiber surface with RGD to mediate cell adhesion and two different antibodies could be achieved. After culturing the cell line HT1080, the pro- or anti-inflammatory response of cells could be detected by IL-8 specific ELISA measurements. Furthermore, the quantification of molecules on the surface of electrospun fibers was investigated. It was tested whether the detection by means of super-resolution microscopy would be possible. Therefore, experiments were performed with short amino acid sequences such as RGD for quantification by fluorescence microscopy. Based on earlier results, in which a UV-spectrometrically active molecule was used to detect the quantification of RGD, it was shown that short peptides can also be quantified in a small scale on flat functional substrates (2D) such as NCO-sP(EO-stat-PO) hydrogel coatings, and modified electrospun fibers produced from PLGA and NCO-sP(EO-stat-PO) (3D). In addition, a collagen sequence was used to prove that a successful quantification can be carried out as well for longer peptide chains. These studies have revealed that NCO-sP(EO-stat-PO) can serve as a functional additive for many applications and should be considered for further studies on the development of novel biomaterials. The rapid crosslinking reaction, the resulting hydrogel formation and the biocompatibility are to be mentioned as positive properties, which makes the prepolymer interesting for future applications. N2 - Ziel der Arbeit war die Anwendung der funktionalen Präpolymere NCO-sP(EO-stat-PO) für die Entwicklung von neuen Biomaterialien. Als erstes wurde untersucht, welchen Einfluss die sternförmigen Polymere auf die mechanischen Eigenschaften von Biozementen und Knochenadhäsiven haben. Beispielsweise wurden 3-armige Macromere als Additive für einen mineralischen Knochenzement verwendet und dessen mechanische Eigenschaften untersucht. Außerdem wurde ein kürzlich entwickelter NCO-sP(EO-stat-PO) haltiger Knochenklebers auf Zytokompatibilität getestet. Ein zweites Kapitel beinhaltete die Modifikation von elektrogesponnenen Polymerfasern mit NCO-sP(EO-stat-PO) basierend auf einer etablierten Methode. Es wurde untersucht, welche weiteren Funktionalisierungen auf solchen Oberflächen vorgenommen werden können. Diese Modifizierungsschritte wurden in einer biologischen Anwendung demonstriert, indem verschiedene Antikörper aufeinanderfolgend auf der Faseroberfläche gebunden wurden. Der Einfluss dieser Proteine auf das Verhalten von Zellen auf diesen Oberflächen wurde untersucht. Als letztes wurde die Quantifizierung von oberflächengebundenen Peptidsequenzen demonstriert. Mittels Funktionalisierung der Peptide mit dem UV-reaktiven Molekül 2-Mercaptopyridin konnte durch Spaltung von Disulfidbrücken diese Verbindung UV-metrisch quantifiziert und indirekt Rückschlüsse auf die Anzahl der immobilisierten Peptide gezogen werden. Durch den Zusatz von NCO-sP(EO-stat-PO) konnten das Abbindeverhalten und die mechanischen Eigenschaften von mineralischen Calciumphosphat-Knochenzementen moduliert werden. Der Zusatz von 3-armigem, sternförmigem NCO-sP(EO-stat-PO) führte dabei zu einem pseudoduktilen Bruchverhalten durch Bildung eines Hydrogelnetzwerks im Zement, das anschließend durch die Zementreaktion mit nanoskaligem Hydroxylapatit mineralisiert wurde. Im Bereich mineralischer Knochenzemente und Adhäsive konnte gezeigt werden, dass NCO-sP(EO-stat-PO) zur Einstellung der Eigenschaften verwendet werden kann. Hierbei wurde dessen Quervernetzungsverhalten im wässrigen Medium ausgenutzt, um mit einer photochemisch härtenden Polyethylenglykoldimethakrylat (PEGDMA) Matrix interpenetrierende Netzwerke (IPNs) zu bilden. Diese konnten für die Entwicklung eines Knochenklebers mit verbesserter Haftung auf Knochen im feuchten Milieu genutzt werden. Das kürzlich entwickelte Knochenadhäsiv wurde im Hinblick auf den Einfluss des Initiatorsystems untersucht. Außerdem wurde die Zytokompatibilität des Materials anhand verschiedener Zelltypen getestet. Die Herstellung von elektrogesponnenen Faservliesen mittels Solution Electrospinning aus Polylactid-co-Glycolid (PLGA) als Gerüst-bildendem Polymer und NCO-sP(EO-stat-PO) als funktionalem Additiv ist eine etablierte Methode, um diese Vliese zur Nachbildung nativer Extrazellulär-Matrix anzuwenden. Die Fasern weisen einen Durchmesser im Nanometer-Bereich auf, sind proteinabweisend durch die hydrophilen Eigenschaften des Präpolymers und können durch Immobilisierung von Peptidsequenzen spezifisch biofunktionalisiert werden. Hierbei wurden die Isocyanate auf der Faseroberfläche genutzt, um verschiedenste Funktionalisierungsschritte unter Beibehaltung der protein- und zellabweisenden Eigenschaften auszuführen. Die Modifizierung der elektrogesponnenen Fasern beinhaltete die Immobilisierung von Analoga oder Antagonisten des Tumornekrosefaktors (TNF) sowie den indirekten Nachweis über eine Lichtreaktion. Hierbei konnte eine multimodale Modifizierung der Faseroberfläche mit RGD-Sequenzen zur Vermittlung der Zelladhäsion und zwei verschiedenen Antikörpern erreicht werden. Nach Kultivierung der Zelllinie HT1080 konnte die pro- oder antiinflammatorische Antwort der Zellen mittels IL-8 spezifischem ELISA nachgewiesen werden. Eine weitere Fragestellung war der Quantifizierung von Molekülen auf der Oberfläche von elektrogesponnen Fasern gewidmet. Es wurde getestet, ob ein Nachweis mittels hochauflösender Mikroskopie möglich ist. Hierzu wurden RGD-Sequenzen zur fluoreszenzmikroskopischen Quantifizierung verwendet. Basierend auf früheren Ergebnissen, bei denen für die Quantifizierung von RGD ein UV-aktives Molekül genutzt wurde, konnte gezeigt werden, dass sich kurze Peptide auch im kleinen Maßstab auf flachen Substraten (2D) wie Hydrogel-Beschichtungen aus NCO-sP(EO-stat-PO) als auch auf elektrogesponnenen Fasern aus PLGA und NCO-sP(EO-stat-PO) (3D) quantifizieren lassen. Außerdem wurde eine Kollagen-Sequenz als längere Peptidkette herangezogen, um auch hier eine erfolgreiche Quantifizierung zu beweisen. Es konnte gezeigt werden, dass NCO-sP(EO-stat-PO) als funktionales Additiv für viele Anwendungen dienen kann und für weitere Untersuchungen zur Entwicklung von Biomaterialien berücksichtigt werden sollte. Die schnelle Quervernetzungsreaktion, die resultierende Hydrogelbildung und die Biokompatibilität sind als positive Eigenschaften zu nennen, die das Präpolymer für zukünftige Anwendungen interessant macht. KW - Sternpolymere KW - Funktionalisierung KW - Isocyanate KW - surface functionalization KW - biomaterials KW - chemical crosslinking KW - bioceramics KW - electrospun fibers KW - Oberflächenfunktionalisierung KW - funktionale Präpolymere KW - Modifikation von Biokeramiken KW - Funktionalisierung von elektrogesponnenen Fasern Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-178365 ER - TY - JOUR A1 - Wintzheimer, Susanne A1 - Oppmann, Maximilian A1 - Dold, Martin A1 - Pannek, Carolin A1 - Bauersfeld, Marie‐Luise A1 - Henfling, Michael A1 - Trupp, Sabine A1 - Schug, Benedikt A1 - Mandel, Karl T1 - Indicator Supraparticles for Smart Gasochromic Sensor Surfaces Reacting Ultrafast and Highly Sensitive JF - Particle & Particle Systems Characterization N2 - The detection of toxic gases, such as NH\(_{3}\) and CO, in the environment is of high interest in chemical, electronic, and automotive industry as even small amounts can display a health risk for workers. Sensors for the real‐time monitoring of these gases should be simple, robust, reversible, highly sensitive, inexpensive and show a fast response. The indicator supraparticles presented herein can fulfill all of these requirements. They consist of silica nanoparticles, which are assembled to supraparticles upon spray‐drying. Sensing molecules such as Reichardt's dye and a binuclear rhodium complex are loaded onto the microparticles to target NH\(_{3}\) and CO detection, respectively. The spray‐drying technique affords high flexibility in primary nanoparticle size selection and thus, easy adjustment of the porosity and specific surface area of the obtained micrometer‐sized supraparticles. This ultimately enables the fine‐tuning of the sensor sensitivity and response. For the application of the indicator supraparticles in a gas detection device, they can be immobilized on a coating. Due to their microscale size, they are large enough to poke out of thin coating layers, thus guaranteeing their gas accessibility, while being small enough to be applicable to flexible substrates. KW - CO sensing KW - NH\(_{3}\) KW - sensor supports KW - silica supraparticles KW - smart surfaces Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-213671 VL - 36 IS - 10 ER - TY - JOUR A1 - Winter, Patrick A1 - Andelovic, Kristina A1 - Kampf, Thomas A1 - Gutjahr, Fabian Tobias A1 - Heidenreich, Julius A1 - Zernecke, Alma A1 - Bauer, Wolfgang Rudolf A1 - Jakob, Peter Michael A1 - Herold, Volker T1 - Fast self-navigated wall shear stress measurements in the murine aortic archusing radial 4D-phase contrast cardiovascular magnetic resonance at 17.6 T JF - Journal of Cardiovascular Magnetic Resonance N2 - Purpose 4D flow cardiovascular magnetic resonance (CMR) and the assessment of wall shear stress (WSS) are non-invasive tools to study cardiovascular risks in vivo. Major limitations of conventional triggered methods are the long measurement times needed for high-resolution data sets and the necessity of stable electrocardiographic (ECG) triggering. In this work an ECG-free retrospectively synchronized method is presented that enables accelerated high-resolution measurements of 4D flow and WSS in the aortic arch of mice. Methods 4D flow and WSS were measured in the aortic arch of 12-week-old wildtype C57BL/6 J mice (n = 7) with a radial 4D-phase-contrast (PC)-CMR sequence, which was validated in a flow phantom. Cardiac and respiratory motion signals were extracted from the radial CMR signal and were used for the reconstruction of 4D-flow data. Rigid motion correction and a first order B0 correction was used to improve the robustness of magnitude and velocity data. The aortic lumen was segmented semi-automatically. Temporally averaged and time-resolved WSS and oscillatory shear index (OSI) were calculated from the spatial velocity gradients at the lumen surface at 14 locations along the aortic arch. Reproducibility was tested in 3 animals and the influence of subsampling was investigated. Results Volume flow, cross-sectional areas, WSS and the OSI were determined in a measurement time of only 32 min. Longitudinal and circumferential WSS and radial stress were assessed at 14 analysis planes along the aortic arch. The average longitudinal, circumferential and radial stress values were 1.52 ± 0.29 N/m2, 0.28 ± 0.24 N/m2 and − 0.21 ± 0.19 N/m2, respectively. Good reproducibility of WSS values was observed. Conclusion This work presents a robust measurement of 4D flow and WSS in mice without the need of ECG trigger signals. The retrospective approach provides fast flow quantification within 35 min and a flexible reconstruction framework. KW - 4D flow KW - WSS KW - OSI KW - Self-navigation KW - Mouse KW - Aortic arch Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-201120 VL - 21 ER - TY - THES A1 - Wiesbeck, Christina T1 - Fabrication and characterization of NCO-sP(EO-stat-PO)- crosslinked and functionalized electrospun gelatin scaffolds for tissue engineering applications T1 - Herstellung und Charakterisierung von elektrogesponnenen Nanofasern aus Gelatine und NCO-sP(EO-stat-PO) für Tissue Engineering Anwendungen N2 - In Tissue Engineering, scaffolds composed of natural polymers often show a distinct lack in stability. The natural polymer gelatin is highly fragile under physiological conditions, nevertheless displaying a broad variety of favorable properties. The aim of this study was to fabricate electrospun gelatin nanofibers, in situ functionalized and stabilized during the spinning process with highly reactive star polymer NCO-sP(EO-stat-PO) (“sPEG”). A spinning protocol for homogenous, non-beaded, 500 to 1000 nm thick nanofibers from different ratios of gelatin and sPEG was successfully established. Fibers were subsequently characterized and tested with SEM imaging, tensile tests, water incubation, FTIR, EDX, and cell culture. It was shown that adding sPEG during the spinning process leads to an increase in visible fiber crosslinking, mechanical stability, and stability in water. The nanofibers were further shown to be biocompatible in cell culture with RAW 264.7 macrophages. N2 - Tissue Engineering Scaffolds aus natürlichen Polymeren zeigen häufig mangelnde Stabilität, insbesondere unter physiologischen Bedingungen. Das natürliche Polymer Gelatine besitzt einige sehr vorteilhafte Eigenschaften für die Anwendung bei der Produktion künstlicher Körpergewebe. Beim Einsatz im menschlichen Organismus ist die Gelatine durch ihre Wasserlöslichkeit höchst fragil. Das Ziel dieser Arbeit war die Herstellung von Nanofaser-Scaffolds aus Gelatine mittels Elektrospinning und deren in situ Stabilisierung durch das Sternpolymer NCO-sP(EO-stat-PO) („sPEG“). Zunächst wurde ein Spinningprotokoll zur Fabrikation homogener, glatter, 500 bis 1000 nm dicker Nanofasern in verschiedenen Verhältnissen von Gelatine und sPEG erarbeitet. Mittels REM Bildgebung, Zugversuchen, Wasserinkubationsversuchen, FTIR, EDX und Zellkultur wurden die Fasern untersucht und charakterisiert. Es konnte gezeigt werden, dass die Zugabe von sPEG während des Spinningprozesses zu einer sichtbaren Quervernetzung der Fasern, sowie zu einem Anstieg der mechanischen Festigkeit und der Wasserstabilität führt. Des Weiteren wurde die Biokompatibilität der Nanofasern in der Zellkultur mit RAW 264.7 Makrophagen belegt. KW - Tissue Engineering KW - Electrospinning KW - Gelatine KW - Polyethylenglykole KW - NCO-sP(EO-stat-PO) KW - sPEG KW - starPEG Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-190988 ER -