TY - JOUR A1 - Pornsawad, Pornsarp A1 - Sapsakul, Nantawan A1 - Böckmann, Christine T1 - A modified asymptotical regularization of nonlinear ill-posed problems JF - Mathematics N2 - In this paper, we investigate the continuous version of modified iterative Runge–Kutta-type methods for nonlinear inverse ill-posed problems proposed in a previous work. The convergence analysis is proved under the tangential cone condition, a modified discrepancy principle, i.e., the stopping time T is a solution of ∥𝐹(𝑥𝛿(𝑇))−𝑦𝛿∥=𝜏𝛿+ for some 𝛿+>𝛿, and an appropriate source condition. We yield the optimal rate of convergence. KW - nonlinear operator KW - regularization KW - discrepancy principle KW - asymptotic method KW - optimal rate Y1 - 2019 U6 - https://doi.org/10.3390/math7050419 SN - 2227-7390 VL - 7 PB - MDPI CY - Basel, Schweiz ET - 5 ER - TY - GEN A1 - Rancan, Fiorenza A1 - Volkmann, Hildburg A1 - Giulbudagian, Michael A1 - Schumacher, Fabian A1 - Stanko, Jessica Isolde A1 - Kleuser, Burkhard A1 - Blume-Peytavi, Ulrike A1 - Calderón, Marcelo A1 - Vogt, Annika T1 - Dermal Delivery of the High-Molecular-Weight Drug Tacrolimus by Means of Polyglycerol-Based Nanogels T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Polyglycerol-based thermoresponsive nanogels (tNGs) have been shown to have excellent skin hydration properties and to be valuable delivery systems for sustained release of drugs into skin. In this study, we compared the skin penetration of tacrolimus formulated in tNGs with a commercial 0.1% tacrolimus ointment. The penetration of the drug was investigated in ex vivo abdominal and breast skin, while different methods for skin barrier disruption were investigated to improve skin permeability or simulate inflammatory conditions with compromised skin barrier. The amount of penetrated tacrolimus was measured in skin extracts by liquid chromatography tandem-mass spectrometry (LC-MS/MS), whereas the inflammatory markers IL-6 and IL-8 were detected by enzyme-linked immunosorbent assay (ELISA). Higher amounts of tacrolimus penetrated in breast as compared to abdominal skin or in barrier-disrupted as compared to intact skin, confirming that the stratum corneum is the main barrier for tacrolimus skin penetration. The anti-proliferative effect of the penetrated drug was measured in skin tissue/Jurkat cells co-cultures. Interestingly, tNGs exhibited similar anti-proliferative effects as the 0.1% tacrolimus ointment. We conclude that polyglycerol-based nanogels represent an interesting alternative to paraffin-based formulations for the treatment of inflammatory skin conditions. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1339 KW - tacrolimus formulation KW - nanogels KW - skin penetration KW - drug delivery KW - human excised skin KW - Jurkat cells Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-473270 SN - 1866-8372 IS - 1339 ER - TY - JOUR A1 - Rancan, Fiorenza A1 - Volkmann, Hildburg A1 - Giulbudagian, Michael A1 - Schumacher, Fabian A1 - Stanko, Jessica Isolde A1 - Kleuser, Burkhard A1 - Blume-Peytavi, Ulrike A1 - Calderon, Marcelo A1 - Vogt, Annika T1 - Dermal Delivery of the High-Molecular-Weight Drug Tacrolimus by Means of Polyglycerol-Based Nanogels JF - Pharmaceutics : Molecular Diversity Preservation International N2 - Polyglycerol-based thermoresponsive nanogels (tNGs) have been shown to have excellent skin hydration properties and to be valuable delivery systems for sustained release of drugs into skin. In this study, we compared the skin penetration of tacrolimus formulated in tNGs with a commercial 0.1% tacrolimus ointment. The penetration of the drug was investigated in ex vivo abdominal and breast skin, while different methods for skin barrier disruption were investigated to improve skin permeability or simulate inflammatory conditions with compromised skin barrier. The amount of penetrated tacrolimus was measured in skin extracts by liquid chromatography tandem-mass spectrometry (LC-MS/MS), whereas the inflammatory markers IL-6 and IL-8 were detected by enzyme-linked immunosorbent assay (ELISA). Higher amounts of tacrolimus penetrated in breast as compared to abdominal skin or in barrier-disrupted as compared to intact skin, confirming that the stratum corneum is the main barrier for tacrolimus skin penetration. The anti-proliferative effect of the penetrated drug was measured in skin tissue/Jurkat cells co-cultures. Interestingly, tNGs exhibited similar anti-proliferative effects as the 0.1% tacrolimus ointment. We conclude that polyglycerol-based nanogels represent an interesting alternative to paraffin-based formulations for the treatment of inflammatory skin conditions. KW - tacrolimus formulation KW - nanogels KW - skin penetration KW - drug delivery KW - human excised skin KW - Jurkat cells Y1 - 2019 U6 - https://doi.org/10.3390/pharmaceutics11080394 SN - 1999-4923 VL - 11 IS - 8 PB - MDPI CY - Basel ER - TY - GEN ED - Muller, Jean-Claude ED - Dietrich, Wolf ED - Monserrat, Ruth ED - Barros, Cândida ED - Arenz, Karl-Heinz ED - Prudente, Gabriel T1 - Dicionário de língua geral amazônica BT - 1ª parte: Português–Língua Geral - 2ª parte: Língua Geral–Português N2 - Permettez à l’inventeur du manuscrit dont vous avez l’édition diplomatique sous les yeux d’exposer en exergue les principales étapes qui ont conduit en 2012 à la détermination de la langue et à l’identification de l’auteur. Étant inscrit à la conférence de linguistique missionnaire à l’université de Brème en mars 2012 et conscient que maintes bibliothèques et archives renferment des trésors non identifiés ou mal catalogués, je suivis le conseil d’un collègue de la bibliothèque de l’université de Trèves, Hans-Ulrich Seiffert, d’inspecter le manuscrit 1136 / 2048 4° de la bibliothèque municipale de Trèves. Cette bibliothèque est riche de plus de 2.500 manuscrits et incunables provenant pour la plupart des saisies révolutionnaires françaises dans les bibliothèques des ci-devant couvents trévirois. Parmi ces trésors un manuscrit portugais des missions qui était rentré dans les fonds de la bibliothèque de Trèves dès 1799 et avait été exposé en 1991 dans le cadre d’une évocation des activités missionnaires globales des Jésuites. Michael Embach, alors directeur de la bibliothèque du séminaire épiscopal de Trèves, l’avait brièvement décrit dans une notice qui prétendait qu’il était rédigé en espagnol et en portugais et avait peut-être été composé par un auteur « Meirin » dans le cadre de ses préparations pour partir dans les missions… Dans ma copie du catalogue de 1991 se trouve inscrit « la langue reste à déterminer ». J’allais résoudre le mystère en cette mémorable journée du jeudi 23 février 2012 quand je me résolus à l’autopsier dans la salle désormais historique de la Bibliothèque municipale de Trèves, dirigée depuis peu par le collègue Embach. Il parut à l’évidence que le manuscrit ne contenait aucun mot d’espagnol mais que dans la première partie, les entrées en portugais, strictement numérotées et arrangées dans l’ordre alphabétique, étaient suivies par leurs équivalences dans une langue inconnue qui, cependant, avait pour un linguiste une forte odeur de l’Amérique amazonienne. La partie postérieure du manuscrit présentait l’arrangement inverse. Les entrées dans la langue inconnue étaient suivies de leurs équivalences portugaises. Ce n’est que plus tard que nous avons compris le mystérieux ordre des lemmata dans cette partie, basée qu’elle est sur la rime finale des mots. Deux facteurs ont grandement facilité l’identification de la langue inconnue : 1. la permission du directeur Embach de pouvoir prendre des photos de travail de tous les folios du manuscrit et 2. l’entrée dans le premier catalogue de la Bibliothèque de Trèves de 1802 : “Codex maxime memorabiblis est, cum nondum grammatica praeter Lusitani Anchieta nota sit, et nullum vocabularium huius linguae existet. Sine dubio scriptum est a quodam Missionario Jesuita”. Rentrant de Trèves chez moi, je fis une brève halte dans mon bureau d’alors pour consulter Internet. L’entrée “Anchieta” dans l’encyclopédie électronique Wikipedia m’informait que ce jésuite portugais avait composé une grammaire du Vieux Tupi, publiée en 1595. Sous le vocable “Old Tupi” ensuite, j’appris que l’auto-désignation pour cette langue est ñeengatú (la bonne langue, le parler correct). De là à retrouver au folio 25 de mes photos la traduction du portugais linguagem par nheénga ne prit que quelques minutes. Dès ce premier soir donc, le mystère de la langue inconnue était résolu! Un projet de recherche international, voire transcontinental allait se mettre peu à peu en place après. À la conférence de Brème, début mars 2012, je fis la connaissance du linguiste et romaniste, le professeur Wolf Dietrich de l’université de Münster en Westphalie, un des meilleurs connaisseurs des parlers amazoniens. Il rentrait avec une copie de mes photos de travail et confirma bientôt l’importance du manuscrit de Trèves pour la connaissance de la Lingua Geral, le parler qui s’était développé à partir du Vieux Tupi moribond. Je communiquai également ma découverte au frère Karl-Heinz Arenz de la congrégation des pères de Steyl, originaire de l’Eifel allemande et enseignant d’histoire aux universités brésiliennes de Belém et de Santarém dans l’État du Pará. Arenz est l’auteur d’une étude sur le jésuite luxembourgeois Jean-Philippe Bettendorf, actif au Maranhão dans la seconde moitié du XVIIe siècle. Nous avions collaboré en 2007 à une exposition didactique consacrée à ce personnage. Arenz ne tarda pas à passer l’information sur le manuscrit de Trèves aux deux linguistes brésiliennes Cândida Barros et Ruth Monserrat, qui à leur tour présentaient un projet de recherche qui fut accepté par les autorités brésiliennes. Les reals de ce subside furent bien investis en effet : l’étudiant doctoral Gabriel Prudente réalisa une transcription intégrale du manuscrit de Trèves qui fit apparaître des couches dialectales et sociolectales dans le texte, et même quelques mots allemands. La bibliothèque municipale de Trèves, quant à elle, contribua « en nature » les images digitales qui sont consultables sur les pages de gauche de cette édition électronique. Début avril 2014, nous fîmes tous connaissance personnellement dans le cadre d’un colloque à l’université de Belém où fut décidée la présente édition digitale et où furent prononcées la plupart des contributions scientifiques que vous pouvez lire en guise d’introduction. Restait à percer l’énigme du véritable auteur du manuscrit. Cândida Barros avait assez tôt proposé les noms de trois Jésuites allemands, actifs dans les années 1750 dans la région du fleuve Xingu et chassés par les mesures anti-jésuites du pouvoir portugais en 1756. L’étude paléographique des Quattuor vota des trois candidats, aux archives centrales des Jésuites à Rome, me permit début septembre 2015 d’éliminer les pères Eckart et Kaulen et de ne retenir que Antonius Meisterburg, originaire de Bernkastel sur la Moselle, comme le scribe du manuscrit de Trèves. Qu’il me soit permis d’exprimer ma GRATITUDE à toutes celles et à tous ceux qui ont contribué à cette belle aventure de découverte intellectuelle et scientifique et à rendre au Brésil une petite pierre de son histoire. N2 - Ich möchte dem Leser dieser diplomatischen Edition des Portugiesisch-Tupi (oder Lingua Geral)-Wörterbuchs des Jesuiten Antonius Meisterburg aus Bernkastel an der Mosel in wenigen Worten schildern, wie es im Jahr 2012 zur Entdeckung und Feststellung sowohl des Autors als auch der damals noch unbekannten Zielsprache kam. Im Vorfeld der Bremer Konferenz über Missionarslinguistik Anfang März 2012 folgte ich dem Hinweis des Bibliothekskollegen Hans-Ulrich Seiffert von der Universitätsbibliothek Trier, doch einmal einen Blick in die Handschrift 1136 / 2048 4° der reichhaltigen Trierer Stadtbibliothek zu werfen. Von diesem kuriosen Manuskript seien weder Sprache noch Autor bekannt, es sei aber sicher das Produkt eines Missionars aus den Missionen. In der Tat war die Handschrift erstmalig im Jahr 1991 in einer der Aktivität der Jesuiten gewidmeten Ausstellung in Trier gezeigt worden. Damals verfasste der Direktor der Bibliothek des Priesterseminars Trier, Michael Embach, eine kurze Katalognotiz, welche aussagte, die Handschrift sei auf Spanisch und Portugiesisch verfasst, vielleicht von einem Autor “Meirin” im Jahr 1756, als Vorbereitung auf seinen Einsatz in den Missionen. Meine Autopsie der Handschrift im mittlerweile historischen Lesesaal der Trierer Stadtbibliothek an jenem denkwürdigen Nachmittag des 23. Februar 2012 ergab sofort als Resultat, dass von Spanisch in der Handschrift überhaupt keine Rede sein konnte; die Wörterbucheinträge im ersten Teil begannen alle mit einem portugiesischen Lemma. Sie waren peinlich genau in strikt alphabetischer Reihenfolge angeordnet und durchnummeriert. Hinter jedem portugieschen Lemma stand ein Ausdruck in einer noch unbekannten Sprache, die für einen Sprachwissenschaftler aber damals bereits stark nach der Amazonasgegend roch. Im hinteren Teil des Manuskripts waren die Sprachen evidenterweise umgekehrt gebraucht, obwohl die Anordnung der Lemmata in der noch unbekannten Sprache rätselhaft schien. Erst später haben wir begriffen, daß in diesem letzten Teil der Endreim das ordnende Prinzip ist. Zwei Faktoren haben dann die Identifizierung der noch unbekannten Sprache gefördert : 1. Direktor Michael Embachs Erlaubnis, von jeder Seite der Handschrift Arbeitsphotographien zu knipsen und 2. der Eintrag des ersten Trierer Bibliothekdirektors Wyttenbach in den Handschriftenkatalog von 1802 : “Codex maxime memorabiblis est, cum nondum grammatica praeter Lusitani Anchieta nota sit, et nullum vocabularium huius linguae existet. Sine dubio scriptum est a quodam Missionario Jesuita”. Auf dem Heimweg von Trier ins westliche Luxemburg legte ich einen kurzen Halt in meinem damaligen Büro auf Buurmecht ein und tauchte in die Wunderwelt des Internet ein. Mich auf die Information im Katalog von 1802 basierend, war es keine Hexerei, beim Namen “Anchieta” herauszufinden, daß dieser portugiesische Jesuit eine Grammatik der brasilianischen Tupisprache verfasst hatte, die 1595 im Druck erschienen war. Der Wikipedia-Eintrag “Alt-Tupi” erläuterte dann, daß die Selbstbenennung in jener Sprache ñeengatú (die gute, die korrekte Sprache) lautete. Einige Augenblicke später hatte ich in meinen Photoaufnahmen auf Seite 25 die Stelle gefunden, wo Portugiesisch linguagem mit nheénga übersetzt wurde. So hatte ich bereits am Abend nach der ersten Konsultation ein wesentliches Rätsel der Trierer Handschrift ”geknackt”. Aus dieser ersten Analyse entwickelte sich über die Monate und Jahre eine internationale wissenschaftliche Zusammenarbeit, die ich zu einem der Höhepunkte meines sprachwissenschaftlichen Curriculum zählen darf. Am Rande der Bremer Konferenz im Frühmärz 2012 lernte ich den Sprachwissenschaftler und Romanisten Professor Wolf Dietrich von der Universität Münster kennen, einen der ausgewiesensten Kenner der Amazonassprachen. Er kehrte mit einer Kopie meiner Trierer Photos nach Hause und bestätigte umgehend die Wichtigkeit des Trierer Wörterbuchs für die Kenntnis der “Lingua geral”, der Sprache, welche sich aus dem aussterbenden Alt-Tupi entwickelt hatte. Auf einer parallelen Schiene informierte ich Bruder Karl-Heinz Arenz, den aus der Eifel stammenden Steylerpater, der in Belém und Santarém im brasilianischen Bundesstaat Pará Geschichte unterrichtet. Ich kannte Karl-Heinz Arenz von seiner Doktorarbeit und unserer Ausstellung über den Luxemburger Jesuiten Bettendorf, der in der zweiten Hälfte des 17. Jh. in Maranhão tätig war. Arenz wiederum zog die Forscherinnen Cândida Barros und Ruth Monserrat ins Vertrauen, die voller Begeisterung für das seltene Sprachzeugnis einen Förderungsantrag beim brasilianischen Staat stellten und genehmigt bekamen. Damit wurde u.a. der Doktoratsstudent Gabriel Prudente bezahlt, um den Text der Trierer Handschrift zu transliterieren und eine Feinanalyse der Schreibschichten zu unternehmen. Das Resultat waren etliche deutsche, in den Text eingesprengte Worterläuterungen, sowie viele dialektale und soziolektale Varianten von Tupi und benachbarten Sprachen. Anfang April 2014 trafen wir uns alle in Belém zu einem Seminar über die Trierer Handschrift, wo diese kommentierte Faksimile-Ausgabe beschlossen wurde. Die Trierer Stadtbibliothek ihrerseits steuerte hoch aufgelöste Digitalbilder gratis bei. Recht früh hatte Cândida Barros vermutet, der Autor der Handschrift sei einer von drei deutschen Jesuiten, die um 1750 am Fluss Xingu, einem Nebenfluss des Amazonas, tätig gewesen waren, ehe sie von der antijesuitischen portugiesischen Politik vertrieben wurden. Im September 2015 konnte ich dann endlich im römischen Zentralarchiv der Jesuiten anhand von Autographen der drei Kandidaten den Bernkasteler Jesuiten Antonius Meisterburg als den eigentlichen Schreiber der Trierer Handschrift identifizieren. Allen, die an dieser faszinierenden sprachwissenschaftlichen und kulturhistorischen Entdeckungsreise beteiligt waren, mein herzlichster DANK! N2 - I feel that I owe the reader a few words of explanation about the circumstances which led to the discovery and identification of both language and author of the Portuguese-Tupi (or Lingua Geral) dictionary authored by the Jesuit missionary Antonius Meisterburg, who hailed from Bernkastel on the river Moselle, near Trier, in Germany. As I was getting ready to attend the Bremen conference on missionary linguistics a week later, it was on February 23rd, 2012, that I heeded the advice of my librarian colleague Hans-Ulrich Seiffert of the Trier University Library to have a second look at manuscript 1136 / 2048 4° at the Trier city library, which is well known for the rich manuscript and incunabula collection which it has been able to constitute after the French Revolution and the dissolution of the former monastic libraries. This undetermined manuscript had first been exhibited publicly in the context of an exhibition about the activities of the Jesuits in 1991. A brief catalogue entry by Michael Embach pretended it was composed in Spanish and Portuguese, possibly by an author “Meirin” in the year 1756, who was preparing himself for his missionary task. My inspection of the original on that memorable afternoon made it soon clear that the text was only in Portuguese, with no Spanish showing up anywhere. In the first half of the manuscript, the Portuguese lemmata, all well arranged and numbered in alphabetical order, would be followed by entries in an unknown language which, already then, had a smell of the Amazonas river area about it. In the second half of the text, the arrangement of the languages was manifestly reversed, though the order of the lemmata in the unknown target language seemed beyond comprehension. It was only later in the project that it dawned on us that in this final part, the order of the lemmata is based indeed on final rime. Two factors significantly furthered the determination of the as yet unknown language : 1. director Michael Embach’s permission to take working photographs of every page of the manuscript, and 2. the first Trier librarian’s entry in the 1802 catalogue affirming that “Codex maxime memorabiblis est, cum nondum grammatica praeter Lusitani Anchieta nota sit, et nullum vocabularium huius linguae existet. Sine dubio scriptum est a quodam Missionario Jesuita”. Consulting the internet on my way home that day, it was no exercise of witchcraft to learn under the entry “Anchieta” that this Portuguese Jesuit had authored a grammar of the Tupi language of Brazil printed in 1595. Furthermore, the entry “Old Tupi” informed me that the autoreferential word for the now extinct language was ñeengatú (the good, the correct language). Finding the equivalent of Portuguese “linguagem” as nheénga on my photograph of folio 25 just took a couple of minutes. The mysterious target language had thus been identified on the very evening of the inspection of the manuscript in Trier. The international collaboration which developed out of this seminal analysis of the original manuscript in the Trier municipal library counts among the most gratifying experiences in my life as a linguist. At the Bremen conference in early March 2012, a contact was established with professor Wolf Dietrich of the University of Münster, one of the most knowledgeable experts of Amazon linguistics, who took home for study my lot of photographs of the Trier manuscript and would soon attest its importance for the knowledge of “Lingua geral”, the language which had developed out of moribund Old Tupi. On a parallel track, I passed on news about my discovery to father Karl-Heinz Arenz, who hails from the Eifel region of Germany, has presented a doctoral thesis on the Luxembourg Jesuit Bettendorf, – who was active in northern Brazil in the latter half of the 17th century –, and is now teaching history in Belém and Santarém in the Brazilian State of Pará. Father Arenz spread the news to researchers Cândida Barros and Ruth Monserrat, who succeeded in obtaining a research grant from the Brazilian State. Those reals were mostly spent very wisely paying the doctoral student Gabriel Prudente to transcribe the manuscript’s text and proceeding to a first internal analysis which yielded some German word explanations plus many dialectal and sociolectal variants of Tupi and neighboring languages. Then came April 2014 with the Belém Seminar about the Trier manuscript which is at the origin of this digital facsimilé edition and of a series of scientific articles. The Trier library had meanwhile contributed digital images of the manuscript in very high resolution. Cândida Barros had already suggested in late 2012 that the Trier manuscript might have been written by any of three German Jesuits who are known for their missionary activities in the area of the river Xingu in the 1750s, before they had been arrested and imprisoned by the anti-Jesuit Portuguese government in 1756. It was only in early September 2015 that I could ascertain the true author of the present manuscript by comparing the handwriting of the manuscript with father Antonius Meisterburg’s autograph text penned down on the occasion of his four vows, and excluding the other two candidates, fathers Eckart and Kaulen, whose handwritings could also be inspected at the Roman archives of the Society of Jesus. For me this project has opened so many windows of knowledge that I simply want to THANK all who have accompanied, helped and counselled me during the last six years. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-416390 SN - 978-85-61377-99-1 N1 - Manuscrito anônimo e sem título, Ms. no 1136 / 2048 4° da Biblioteca Municipal de Trier, Alemanha Missão de Piraguiri, Baixo Xingu, antes de 1756 Edição diplomática, revisada e ampliada com comentários e anexos por Wolf Dietrich, Ruth Monserrat e Jean-Claude Muller, com a reprodução fotográfica do original do manuscrito Primeira transcrição por Gabriel Prudente PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - RPRT A1 - Müller, Kai-Uwe A1 - Wrohlich, Katharina T1 - Does subsidized care for toddlers increase maternal labor supply? BT - Evidence from a large-scale expansion of early childcare T2 - CEPA Discussion Papers N2 - Expanding public or publicly subsidized childcare has been a top social policy priority in many industrialized countries. It is supposed to increase fertility, promote children’s development and enhance mothers’ labor market attachment. In this paper, we analyze the causal effect of one of the largest expansions of subsidized childcare for children up to three years among industrialized countries on the employment of mothers in Germany. Identification is based on spatial and temporal variation in the expansion of publicly subsidized childcare triggered by two comprehensive childcare policy reforms. The empirical analysis is based on the German Microcensus that is matched to county level data on childcare availability. Based on our preferred specification which includes time and county fixed effects we find that an increase in childcare slots by one percentage point increases mothers’ labor market participation rate by 0.2 percentage points. The overall increase in employment is explained by the rise in part-time employment with relatively long hours (20-35 hours per week). We do not find a change in full-time employment or lower part-time employment that is causally related to the childcare expansion. The effect is almost entirely driven by mothers with medium-level qualifications. Mothers with low education levels do not profit from this reform calling for a stronger policy focus on particularly disadvantaged groups in coming years. T3 - CEPA Discussion Papers - 9 KW - childcare provision KW - mother’s labor supply KW - generalized difference-in-difference Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-427727 SN - 2628-653X IS - 9 ER - TY - THES A1 - Yishai, Oren T1 - Engineering the reductive glycine pathway in Escherichia coli Y1 - 2019 ER - TY - THES A1 - Beamish, Alison Leslie T1 - Hyperspectral remote sensing of the spatial and temporal heterogeneity of low Arctic vegetation T1 - Hyperspektrale Fernerkundung der räumlichen und zeitlichen Heterogenität niedriger arktischer Vegetation BT - the role of phenology, vegetation colour, and intrinsic ecosystem components BT - die Rolle von Phänologie, Vegetationsfarbe und intrinsischer Ökosystemkomponenten N2 - Arctic tundra ecosystems are experiencing warming twice the global average and Arctic vegetation is responding in complex and heterogeneous ways. Shifting productivity, growth, species composition, and phenology at local and regional scales have implications for ecosystem functioning as well as the global carbon and energy balance. Optical remote sensing is an effective tool for monitoring ecosystem functioning in this remote biome. However, limited field-based spectral characterization of the spatial and temporal heterogeneity limits the accuracy of quantitative optical remote sensing at landscape scales. To address this research gap and support current and future satellite missions, three central research questions were posed: • Does canopy-level spectral variability differ between dominant low Arctic vegetation communities and does this variability change between major phenological phases? • How does canopy-level vegetation colour images recorded with high and low spectral resolution devices relate to phenological changes in leaf-level photosynthetic pigment concentrations? • How does spatial aggregation of high spectral resolution data from the ground to satellite scale influence low Arctic tundra vegetation signatures and thereby what is the potential of upcoming hyperspectral spaceborne systems for low Arctic vegetation characterization? To answer these questions a unique and detailed database was assembled. Field-based canopy-level spectral reflectance measurements, nadir digital photographs, and photosynthetic pigment concentrations of dominant low Arctic vegetation communities were acquired at three major phenological phases representing early, peak and late season. Data were collected in 2015 and 2016 in the Toolik Lake Research Natural Area located in north central Alaska on the North Slope of the Brooks Range. In addition to field data an aerial AISA hyperspectral image was acquired in the late season of 2016. Simulations of broadband Sentinel-2 and hyperspectral Environmental and Mapping Analysis Program (EnMAP) satellite reflectance spectra from ground-based reflectance spectra as well as simulations of EnMAP imagery from aerial hyperspectral imagery were also obtained. Results showed that canopy-level spectral variability within and between vegetation communities differed by phenological phase. The late season was identified as the most discriminative for identifying many dominant vegetation communities using both ground-based and simulated hyperspectral reflectance spectra. This was due to an overall reduction in spectral variability and comparable or greater differences in spectral reflectance between vegetation communities in the visible near infrared spectrum. Red, green, and blue (RGB) indices extracted from nadir digital photographs and pigment-driven vegetation indices extracted from ground-based spectral measurements showed strong significant relationships. RGB indices also showed moderate relationships with chlorophyll and carotenoid pigment concentrations. The observed relationships with the broadband RGB channels of the digital camera indicate that vegetation colour strongly influences the response of pigment-driven spectral indices and digital cameras can track the seasonal development and degradation of photosynthetic pigments. Spatial aggregation of hyperspectral data from the ground to airborne, to simulated satel-lite scale was influenced by non-photosynthetic components as demonstrated by the distinct shift of the red edge to shorter wavelengths. Correspondence between spectral reflectance at the three scales was highest in the red spectrum and lowest in the near infra-red. By artificially mixing litter spectra at different proportions to ground-based spectra, correspondence with aerial and satellite spectra increased. Greater proportions of litter were required to achieve correspondence at the satellite scale. Overall this thesis found that integrating multiple temporal, spectral, and spatial data is necessary to monitor the complexity and heterogeneity of Arctic tundra ecosystems. The identification of spectrally similar vegetation communities can be optimized using non-peak season hyperspectral data leading to more detailed identification of vegetation communities. The results also highlight the power of vegetation colour to link ground-based and satellite data. Finally, a detailed characterization non-photosynthetic ecosystem components is crucial for accurate interpretation of vegetation signals at landscape scales. N2 - Die arktische Erwärmung beeinflusst Produktivität, Wachstums, Artenzusammensetzung, Phänologie und den Reproduktionserfolg arktischer Vegetation, mit Auswirkungen auf die Ökosystemfunktionen sowie auf den globalen Kohlenstoff- und Energiehaushalt. Feldbasierte Messungen und spektrale Charakterisierungen der räumlichen und zeitlichen Heterogenität arktischer Vegetationsgemeinschaften sind limitiert und die Genauigkeit fernerkundlicher Methoden im Landschaftsmaßstab eingeschränkt. Um diese Forschungslücke zu schließen und aktuelle und zukünftige Satellitenmissionen zu unterstützen, wurden drei zentrale Forschungsfragen entwickelt: 1) Wie unterscheidet sich die spektrale Variabilität des Kronendaches zwischen dominanten Vegetationsgemeinschaften der niederen Arktis und wie verändert sich diese Variabilität zwischen den wichtigsten phänologischen Phasen? 2) Wie hängen Aufnahmen der Vegetationsfarbe des Kronendaches von hoch und niedrig auflösenden Geräten mit phänologischen Veränderungen des photosynthetischen Pigmentgehalts auf Blattebene zusammen? 3) Wie beeinflusst die räumliche Aggregation von Daten mit hoher spektraler Auflösung von der Boden- bis zur Satelliten-Skala die arktischen Vegetationssignale der Tundra und welches Potenzial haben zukünftige hyperspektraler Satellitensysteme für die arktische Vegetationscharakterisierung? Zur Beantwortung dieser Fragen wurde eine detaillierte Datenbank aus feldbasierten Daten erstellt und mit hyperspektralen Luftbildern sowie multispektralen Sentinel-2 und simulierten hyperspektralen EnMAP Satellitendaten verglichen. Die Ergebnisse zeigten, dass die Spätsai-son am besten geeignet ist um dominante Vegetationsgemeinschaften mit Hilfe von hyper-spektralen Daten zu identifizieren. Ebenfalls konnte gezeigt werden, dass die mit handelsüb-lichen Digitalkameras aufgenommene Vegetationsfarbe pigmentgesteuerte Spektralindizes stark beeinflusst und den Verlauf von photosynthetischen Pigmenten nachverfolgen kann. Die räumliche Aggregation hyperspektraler Daten von der Boden- über die Luft- zur Satelli-tenskala wurde durch nicht-photosynthetische Komponenten beeinflusst und die spektralen Reflexionsvermögen der drei Skalen stimmten im roten Spektrum am höchsten und im nahen Infrarotbereich am niedrigsten überein. Die vorliegende Arbeit zeigt, dass die Integration zeitlicher, spektraler und räumlicher Daten notwendig ist, um Komplexität und Heterogenität arktischer Vegetationsreaktionen in Reaktion auf klimatische Veränderungen zu überwachen. KW - hyperspectral remote sensing KW - Arctic tundra KW - vegetation KW - imaging spectroscopy KW - hyperspektral Fernerkundung KW - arktische Tundra KW - Vegetation KW - Spektroskopie Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-425922 ER - TY - THES A1 - Ruiz Rodriguez, Janete Lorena T1 - Osmotic pressure effects on collagen mimetic peptides N2 - Collagen is the most abundant protein in mammals. In many tissues, collagen molecules assemble to form a hierarchical structure. In the smallest supramolecular unit, named fibril, each molecule is displaced in the axial direction with respect to its neighbors. This staggering creates a periodic gap and overlap regions, where the gap regions exhibit 20% less density. These fibril-forming collagens play an essential role in the strength of connective tissues. Despite much effort, directed at understanding collagen function and regulation, the influence of the chemical environment on the local structural and mechanical properties remains poorly understood. Recent studies, aimed at elucidating the effect of osmotic pressure, showed that collagen contracts upon water removal. This observation highlights the importance of water for the stabilization and mechanics of the collagen molecule. Using collagen mimetic peptides (CMPs), which fold into triple helical structures reminiscent of natural collagen, the primary goal of this work was to investigate the effect of the osmotic pressure on specific collagen-mimetic sequences. CMPs were used as the model system as they provide sequence control, which is essential for discriminating local from global structural changes and for relating the observed effects to existing knowledge about the full-length collagen molecule. Of specific interest was the structure of individual collagen triple helices as well as their organization into self-assembled higher order structures. These key structural features were monitored with infrared spectroscopy (IR) and synchrotron X-ray scattering, while varying the osmotic pressure. For controlling the osmotic pressure, CMP powder samples were incubated in air of defined relative humidity, ranging from dry conditions to highly “humid”. In addition, to obtain more biologically relevant conditions, the CMPs were measured in ultrapure water and in solutions containing small molecule osmolytes. Using the sequences (Pro-Pro-Gly)10, (Pro-Hyp-Gly)10 and (Hyp-Hyp-Gly)10, it was shown that CMPs with different degrees of proline hydroxylation (Hyp = hydroxyproline) exhibit a sequence-specific response to osmotic pressure. IR spectroscopy revealed that osmotic pressure changes affect the strength of the triple helix stabilizing, interchain hydrogen bond and that the extent of this change depends on the degree of hydroxylation. X-ray scattering experiments further showed that changes in osmotic pressure affect both the molecular length as well as the higher order organization of CMPs. Starting from a pseudo-hexagonal packing in the dry state, all three CMPs showed isotropic swelling when increasing the water content to approximately 1.2 water molecules per amino acid, again to different extents depending on the degree of hydroxylation. When increasing the water content further, this pseudo-hexagonal arrangement breaks down. In the fully hydrated state, each CMP is characterized by its own specific and more complex packing geometry. While these changes in the lateral packing arrangement suggest swelling upon hydration, an overall decrease of the molecular length (i.e. contraction) was observed in the axial direction. Also for this structural feature, a strong dependency on the specific amino acid sequence was found. Interestingly, the observed contraction is the opposite of what has been reported for natural collagen. As (Pro-Pro-Gly)n, (Pro-Hyp-Gly)n and (Hyp-Hyp-Gly)n repeat units are found in collagen with a relatively high abundance, this suggests that other collagen sequence fragments need to respond to hydration in the opposite way to obtain a net elongation of the full-length collagen molecule. To test this hypothesis, sequences predicted to be sensitive to osmotic pressure were considered. One such sequence, consisting of two repeat units (Ala-Arg-Gly-Ser-Asp-Gly), was inserted as a guest into a (Pro-Pro-Gly) host. When compared to the canonical CMP sequences investigated earlier, the lateral helix packing follows a similar trend with increasing hydration; however, the host-guest CMP axially elongates with increasing water content. This behavior is more similar to what has been found for natural collagen and suggests that different sequences do determine the molecular length of collagen sequences differently. Interestingly, the canonical sequences are more abundant in the overlap region while the guest sequence is found in the gap region. This allows to speculate that sequences in the gap and overlap regions possess a specifically fine-tuned local response to osmotic pressure changes. Clearly, more experiments with additional sequences are needed to confirm this. In conclusion, the results obtained in this work indicate a highly sequence specific interaction between collagen and water. Osmotic pressure-induced conformational changes mostly originate from local geometries and bonding patterns and affect both the structure of individual triple helices as well as higher order assemblies. One key remaining question is how these conformational changes affect the local mechanical properties of the collagen molecule. As a first step, the stiffness (persistence length) of full-length collagen was determined using atomic force microscopy. In the future, experimental strategies need to be developed that allow for investigating the mechanical properties of specific collagen sequences, e.g. performing single-molecule force spectroscopy of CMPs. Y1 - 2019 ER - TY - GEN A1 - Kotthoff, Lisa A1 - Lisec, Jan A1 - Schwerdtle, Tanja A1 - Koch, Matthias T1 - Prediction of transformation products of monensin by electrochemistry compared to microsomal assay and hydrolysis T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The knowledge of transformation pathways and identification of transformation products (TPs) of veterinary drugs is important for animal health, food, and environmental matters. The active agent Monensin (MON) belongs to the ionophore antibiotics and is widely used as a veterinary drug against coccidiosis in broiler farming. However, no electrochemically (EC) generated TPs of MON have been described so far. In this study, the online coupling of EC and mass spectrometry (MS) was used for the generation of oxidative TPs. EC-conditions were optimized with respect to working electrode material, solvent, modifier, and potential polarity. Subsequent LC/HRMS (liquid+ chromatography/high resolution mass spectrometry) and MS/MS experiments were performed to identify the structures of derived TPs by a suspected target analysis. The obtained EC-results were compared to TPs observed in metabolism tests with microsomes and hydrolysis experiments of MON. Five previously undescribed TPs of MON were identified in our EC/MS based study and one TP, which was already known from literature and found by a microsomal assay, could be confirmed. Two and three further TPs were found as products in microsomal tests and following hydrolysis, respectively. We found decarboxylation, O-demethylation and acid-catalyzed ring-opening reactions to be the major mechanisms of MON transformation T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1340 KW - transformation products KW - monensin KW - veterinary drugs KW - electrochemistry KW - hydrolysis KW - LC/HRMS Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-473262 SN - 1866-8372 IS - 1340 ER - TY - JOUR A1 - Kotthoff, Lisa A1 - Lisec, Jan A1 - Schwerdtle, Tanja A1 - Koch, Matthias T1 - Prediction of transformation products of monensin by electrochemistry compared to microsomal assay and hydrolysis JF - Molecules N2 - The knowledge of transformation pathways and identification of transformation products (TPs) of veterinary drugs is important for animal health, food, and environmental matters. The active agent Monensin (MON) belongs to the ionophore antibiotics and is widely used as a veterinary drug against coccidiosis in broiler farming. However, no electrochemically (EC) generated TPs of MON have been described so far. In this study, the online coupling of EC and mass spectrometry (MS) was used for the generation of oxidative TPs. EC-conditions were optimized with respect to working electrode material, solvent, modifier, and potential polarity. Subsequent LC/HRMS (liquid chromatography/high resolution mass spectrometry) and MS/MS experiments were performed to identify the structures of derived TPs by a suspected target analysis. The obtained EC-results were compared to TPs observed in metabolism tests with microsomes and hydrolysis experiments of MON. Five previously undescribed TPs of MON were identified in our EC/MS based study and one TP, which was already known from literature and found by a microsomal assay, could be confirmed. Two and three further TPs were found as products in microsomal tests and following hydrolysis, respectively. We found decarboxylation, O-demethylation and acid-catalyzed ring-opening reactions to be the major mechanisms of MON transformation. KW - transformation products KW - monensin KW - veterinary drugs KW - electrochemistry KW - hydrolysis KW - LC/HRMS Y1 - 2019 U6 - https://doi.org/10.3390/molecules24152732 SN - 1420-3049 VL - 24 IS - 15 PB - MDPI CY - Basel ER -