TY - THES A1 - Kunstmann, Ruth Sonja T1 - Design of a high-affinity carbohydrate binding protein T1 - Design eines hoch-affin Kohlenhydrat-bindenden Proteins N2 - Kohlenhydrat-Protein Interaktionen sind in der Natur weitverbreitet. Sie stellen die Grundlage für viele biologische Prozesse dar, wie zum Beispiel Immunantworten, Wundheilung und Infektionsprozesse von pathogenen Viren oder Bakterien mit einem Wirt wie dem Menschen. Neben der Infektion von Menschen können aber auch Bakterien selbst durch so genannte Bakteriophagen infiziert werden, welche für den Menschen ungefährlich sind. Diese Infektion involviert die spezifische Erkennung der pathogenen Bakterien, die Vermehrung der Bakteriophagen und schließlich die Abtötung der Bakterien. Dabei können die Mechanismen der spezifischen Erkennung genutzt werden, pathogene Bakterien auf Lebensmitteln zu detektieren oder die Diagnose von Infektionen zu vereinfachen. Die spezifische Erkennung von Enteritis-erzeugenden Bakterien wie Escherichia coli, Salmonella spp. oder Shigella flexneri durch Bakteriophagen der Familie der Podoviridae erfolgt über die Bindung eines sogenannten tailspike proteins des Bakteriophagen an das aus Kohlenhydraten-bestehende O-Antigen des Lipopolysaccharids von Gram-negativen Bakterien. Das tailspike protein spaltet das O-Antigen um den Bakteriophage an die Oberfläche des Bakteriums zu führen, damit eine Infektion stattfinden kann. Die Affinität des tailspike proteins zum O-Antigen ist dabei sehr niedrig, um nach Spaltung des O-Antigens das Spaltungsprodukt zu lösen und wiederum neues Substrat zu binden. In dieser Arbeit wurde ein tailspike protein des Bakteriophagen Sf6 verwendet (Sf6 TSP), das spezifisch an das O-Antigen von Shigella flexneri Y bindet. Eine inaktive Variante des Sf6 TSP wurde verwendet um einen hoch-affin bindenden Sensor für pathogene Shigella zu entwickeln. Der Shigella-Sensor wurde durch Kopplung von unterschiedlichen Proteinmutanten mit einem fluoreszierendem Molekül erhalten. Dabei zeigte eine dieser Mutanten bei Bindung von Shigella O-Antigen ein Fluoreszenz-Signal im Bereich des sichtbaren Lichts. Molekulardynamische Simulationen wurde anhand der erzeugten Proteinmutanten als Methode zum rationalen Design von hoch-affin Kohlenhydrat-bindenden Proteinen getestet und die resultierenden Affinitätsvorhersagen wurden über Oberflächenplasmonresonanz-Experimente überprüft. Aus weiteren experimentellen und simulierten Daten konnten schließlich Schlussfolgerungen über die Ursprünge von Kohlenhydrat-Protein Interaktionen gezogen werden, die eine Einsicht über den Einfluss von Wasser in diesem Bindungsprozess lieferten. N2 - Carbohydrate-protein interactions are ubiquitous in nature. They provide the initial molecular contacts in many cell-cell processes as for example immune responses, signal transduction, egg fertilization and infection processes of pathogenic viruses and bacteria. Furthermore, bacteria themselves are infected by bacteriophages, viruses which can cause the bacterial lysis, but do not affect other hosts. The infection process of a bacteriophage involves the specific detection and binding of the bacterium, which can be based on a carbohydrate-protein interaction. The mechanism of specific detection of pathogenic bacteria can thereby be useful for the development of bacteria sensors in the food industry or for tools in diagnostics. Bacteriophages of the Podoviridae family use tailspike proteins for the specific detection of enteritis causing bacteria as Escherichia coli, Salmonella spp. or Shigella flexneri. The tailspike protein provides the first contact by binding to the carbohydrate containing O-antigen part of lipopolysaccharide in the Gram-negative cell wall. After binding to O-antigen repeating units, the enzymatic activity of tailspike proteins leads to cleavage of the carbohydrate chains, which enables the bacteriophage to approach the bacterial surface for DNA injection. Tailspike proteins thereby exhibit a relatively low affinity to the oligosaccharide structures of O-antigen due to the necessary binding, cleavage and release cycle, compared for example to antibodies. In this work it was aimed to study the determinants that influence carbohydrate affinity in the extended TSP binding grooves. This is a prerequisite to design a high-affinity tailspike protein based bacteria sensor. For this purpose the tailspike protein of the bacteriophage Sf6 (Sf6 TSP) was used, which specifically binds Shigella flexneri Y O-antigen with two tetrasaccharide repeating units at the intersubunits of the trimeric β-helix protein. The Sf6 TSP endorhamnosidase cleaves the O-antigen, which leads to an octasaccharide as the main product. The binding affinity of inactive Sf6 TSP towards polysaccharide was characterized by fluorescence titration experiments and surface plasmon resonance (SPR). Moreover, cysteine mutations were introduced into the Sf6 TSP binding site for the covalent thiol-coupling of an environment-sensitive fluorescent label to obtain a sensor for Shigella flexneri Y based on TSP-O-antigen recognition. This sensor showed a more than 100 % amplitude increase of a visible light fluorescence upon the binding of a polysaccharide test solution. Improvements of the TSP sensor can be achieved by increasing the tailspike affinity towards the O-antigen. Therefore molecular dynamics simulations evaluating ligand flexibility, hydrogen bond occupancies and water network distributions were used for affinity prediction on the available cysteine mutants of Sf6 TSP. The binding affinities were experimentally analyzed by SPR. This combined computational and experimental set-up for the design of a high-affinity carbohydrate binding protein could successfully distinguish strongly increased and decreased affinities of single amino acid mutants. A thermodynamically and structurally well characterized set of another tailspike protein HK620 TSP with high-affinity mutants was used to evaluate the influence of water molecules on binding affinity. The free enthalpy of HK620 TSP oligosaccharide complex formation thereby either derived from the replacement of a conserved water molecule or by immobilization of two water molecules upon ligand binding. Furthermore, the enthalpic and entropic contributions of water molecules in a hydrophobic binding pocket could be assigned by free energy calculations. The findings in this work can be helpful for the improvement of carbohydrate docking and carbohydrate binding protein engineering algorithms in the future. KW - Kohlenhydrat-Protein Interaction KW - carbohydrate-protein interaction KW - bacterial sensor KW - Bakterien Sensor Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-403458 ER - TY - GEN A1 - Gast, Klaus A1 - Schüler, Anja A1 - Wolff, Martin A1 - Thalhammer, Anja A1 - Berchtold, Harald A1 - Nagel, Norbert A1 - Lenherr, Gudrun A1 - Hauck, Gerrit A1 - Seckler, Robert T1 - Rapid-acting and human insulins BT - hexamer dissociation kinetics upon dilution of the pharmaceutical formulation T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - Purpose: Comparison of the dissociation kinetics of rapid-acting insulins lispro, aspart, glulisine and human insulin under physiologically relevant conditions. Methods: Dissociation kinetics after dilution were monitored directly in terms of the average molecular mass using combined static and dynamic light scattering. Changes in tertiary structure were detected by near-UV circular dichroism. Results: Glulisine forms compact hexamers in formulation even in the absence of Zn2+. Upon severe dilution, these rapidly dissociate into monomers in less than 10 s. In contrast, in formulations of lispro and aspart, the presence of Zn2+ and phenolic compounds is essential for formation of compact R6 hexamers. These slowly dissociate in times ranging from seconds to one hour depending on the concentration of phenolic additives. The disadvantage of the long dissociation times of lispro and aspart can be diminished by a rapid depletion of the concentration of phenolic additives independent of the insulin dilution. This is especially important in conditions similar to those after subcutaneous injection, where only minor dilution of the insulins occurs. Conclusion: Knowledge of the diverging dissociation mechanisms of lispro and aspart compared to glulisine will be helpful for optimizing formulation conditions of rapid-acting insulins. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 795 KW - circular dichroism KW - dissociation kinetics KW - insulin analog KW - light scattering KW - rapid-acting Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-431572 SN - 1866-8372 IS - 795 SP - 2270 EP - 2286 ER - TY - GEN A1 - Breuninger, Holger A1 - Lenhard, Michael T1 - Expression of the central growth regulator BIG BROTHER is regulated by multiple cis-elements N2 - Background Much of the organismal variation we observe in nature is due to differences in organ size. The observation that even closely related species can show large, stably inherited differences in organ size indicates a strong genetic component to the control of organ size. Despite recent progress in identifying factors controlling organ growth in plants, our overall understanding of this process remains limited, partly because the individual factors have not yet been connected into larger regulatory pathways or networks. To begin addressing this aim, we have studied the upstream regulation of expression of BIG BROTHER (BB), a central growth-control gene in Arabidopsis thaliana that prevents overgrowth of organs. Final organ size and BB expression levels are tightly correlated, implying the need for precise control of its expression. BB expression mirrors proliferative activity, yet the gene functions to limit proliferation, suggesting that it acts in an incoherent feedforward loop downstream of growth activators to prevent over-proliferation. Results To investigate the upstream regulation of BB we combined a promoter deletion analysis with a phylogenetic footprinting approach. We were able to narrow down important, highly conserved, cis-regulatory elements within the BB promoter. Promoter sequences of other Brassicaceae species were able to partially complement the A. thaliana bb-1 mutant, suggesting that at least within the Brassicaceae family the regulatory pathways are conserved. Conclusions This work underlines the complexity involved in precise quantitative control of gene expression and lays the foundation for identifying important upstream regulators that determine BB expression levels and thus final organ size. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 374 KW - Asymmetric interlaced PCR KW - Organ Groth KW - DNA Elements KW - Arabidopsis KW - Plants KW - Brassicaceae KW - Phylogeny KW - Database KW - Place KW - Size Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-400971 ER - TY - THES A1 - Paape, Dario L. J. F. T1 - Antecedent complexity effects on ellipsis processing T1 - Einflüsse der Antezedenskomplexität auf die Verarbeitung von Ellipsen N2 - This dissertation explores whether the processing of ellipsis is affected by changes in the complexity of the antecedent, either due to added linguistic material or to the presence of a temporary ambiguity. Murphy (1985) hypothesized that ellipsis is resolved via a string copying procedure when the antecedent is within the same sentence, and that copying longer strings takes more time. Such an account also implies that the antecedent is copied without its structure, which in turn implies that recomputing its syntax and semantics may be necessary at the ellipsis gap. Alternatively, several accounts predict null effects of antecedent complexity, as well as no reparsing. These either involve a structure copying mechanism that is cost-free and whose finishing time is thus independent of the form of the antecedent (Frazier & Clifton, 2001), treat ellipsis as a pointer into content-addressable memory with direct access (Martin & McElree, 2008, 2009), or assume that one structure is ‘shared’ between antecedent and gap (Frazier & Clifton, 2005). In a self-paced reading study on German sluicing, temporarily ambiguous garden-path clauses were used as antecedents, but no evidence of reparsing in the form of a slowdown at the ellipsis site was found. Instead, results suggest that antecedents which had been reanalyzed from an initially incorrect structure were easier to retrieve at the gap. This finding that can be explained within the framework of cue-based retrieval parsing (Lewis & Vasishth, 2005), where additional syntactic operations on a structure yield memory reactivation effects. Two further self-paced reading studies on German bare argument ellipsis and English verb phrase ellipsis investigated if adding linguistic content to the antecedent would increase processing times for the ellipsis, and whether insufficiently demanding comprehension tasks may have been responsible for earlier null results (Frazier & Clifton, 2000; Martin & McElree, 2008). It has also been suggested that increased antecedent complexity should shorten rather than lengthen retrieval times by providing more unique memory features (Hofmeister, 2011). Both experiments failed to yield reliable evidence that antecedent complexity affects ellipsis processing times in either direction, irrespectively of task demands. Finally, two eye-tracking studies probed more deeply into the proposed reactivation-induced speedup found in the first experiment. The first study used three different kinds of French garden-path sentences as antecedents, with two of them failing to yield evidence for reactivation. Moreover, the third sentence type showed evidence suggesting that having failed to assign a structure to the antecedent leads to a slowdown at the ellipsis site, as well as regressions towards the ambiguous part of the sentence. The second eye-tracking study used the same materials as the initial self-paced reading study on German, with results showing a pattern similar to the one originally observed, with some notable differences. Overall, the experimental results are compatible with the view that adding linguistic material to the antecedent has no or very little effect on the ease with which ellipsis is resolved, which is consistent with the predictions of cost-free copying, pointer-based approaches and structure sharing. Additionally, effects of the antecedent’s parsing history on ellipsis processing may be due to reactivation, the availability of multiple representations in memory, or complete failure to retrieve a matching target. N2 - Diese Dissertation untersucht, ob die Verarbeitung elliptischer Strukturen von Veränderungen der Komplexität des Antezedens beeinflusst wird, entweder durch zusätzliches linguistisches Material oder durch die Präsenz einer temporären Ambiguität. Murphy (1985) stellte die Hypothese auf, dass Ellipsen durch das Kopieren von Zeichenketten aufgelöst werden, sofern das Antezedens sich im selben Satz befindet, und dass das Kopieren längerer Zeichenketten mehr Zeit in Anspruch nimmt. Ein solcher Ansatz impliziert auch, dass das Antezedens ohne seine Struktur kopiert wird, was wiederum impliziert, dass seine Struktur und Semantik an der Auslassungsstelle möglicherweise erneut berechnet werden müssen. Alternativ existieren mehrere Ansätze, die Nulleffekte der Antezedenskomplexität sowie keine strukturelle Neuberechnung vorhersagen. Diese Ansätze involvieren entweder einen Mechanismus, der die bestehende Struktur kostenfrei überträgt und dessen Latenz von der Form des Antezedens unabhängig ist (Frazier & Clifton, 2001), behandeln die Ellipse als Verweis in einen inhaltsadressierbaren Gedächtnisspeicher (Martin & McElree, 2008, 2009) oder nehmen an, dass die Struktur des Antezedens mit der Ellipse "geteilt" wird (Frazier & Clifton, 2005). In einer Self-Paced Reading-Studie mit deutschen Sluicing-Strukturen wurden temporär ambige Garden Path-Sätze als Antezedenten verwendet, es konnte aber keine Evidenz für strukturelle Neuberechnung in Form höherer Lesezeiten am Punkt der Ellipse gefunden werden. Stattdessen zeigte sich, dass Antezedenten, deren ursprünglich inkorrekt zugewiesene Strukturen reanalysiert worden waren, am Punkt der Ellipse leichter abzurufen waren. Dieses Resultat kann im Kontext des Cue-Based Retrieval Parsing (Lewis & Vasishth, 2005) erklärt werden, wo zusätzliche syntaktische Operationen auf einer Struktur zur Stärkung der assoziierten Gedächtnisspur führen. Zwei weitere Self-Paced Reading-Studien zu deutschen Bare Argument-Ellipsen und englischen VP-Ellipsen sollten ausloten, ob zusätzliches linguistisches Material im Antezedens zu längeren Verarbeitungszeiten für die Ellipse führen würde und ob zu wenig fordernde Verständnistests der Grund für frühere Nullresultate waren (Frazier & Clifton, 2000; Martin & McElree, 2008). Auch gibt es die Theorie, dass erhöhte Komplexität des Antezedens Abrufzeiten verkürzen und nicht verlangsamen sollte, da mehr einzigartige Gedächtnismerkmale zur Verfügung stehen (Hofmeister, 2011). Beide Experimente lieferten keine Evidenz für einen Einfluss der Antezedenskomplexität auf die Verarbeitungszeit der Ellipse in die eine oder in die andere Richtung, unabhängig von der Aufgabenschwierigkeit. Schließlich wurde in zwei Eyetracking-Studien der in der ersten Studie beschriebene Reaktivierungseffekt genauer betrachtet. Die erste dieser Studien verwendete drei verschiedene Typen von Garden Path-Strukturen im Französischen als Antezedenten, von denen zwei keine Evidenz für Reaktivierung zeigten. Darüber hinaus zeigte die dritte getestete Struktur Evidenz dafür, dass eine Verlangsamung am Punkt der Ellipse sowie Regressionen zum Antezedens auftreten, wenn dem Antezedens anfänglich keine Struktur zugewiesen wurde. Die zweite Eyetracking-Studie verwendete dieselben deutschen Materialen wie die ursprüngliche Self-Paced Reading-Studie, mit größtenteils ähnlichen Resultaten und einigen beachtenswerten Abweichungen. Insgesamt sind die experimentellen Ergebnisse mit der Ansicht kompatibel, dass das Hinzufügen von linguistischen Material zum Antezedens keine oder nur sehr minimale Effekte auf die Verarbeitungszeit der Ellipse hat, was mit den Vorhersagen auf Basis eines kostenfreien Kopiermechanismus, eines inhaltsadressierten Gedächtnisspeichers oder einer "geteilten" Struktur übereinstimmt. Effekte, die sich aus der Verarbeitungsgeschichte des Antezedens ergeben, sind möglicherweise auf Reaktivierung, das Vorhandensein mehrerer Gedächtnisspuren oder ein komplettes Scheitern des Gedächtnisabrufs zurückzuführen. KW - ellipsis KW - antecedent complexity KW - psycholinguistics KW - task demands KW - garden path KW - Ellipse KW - Psycholinguistik KW - Temporäre Ambiguität Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-411689 ER - TY - GEN A1 - Stelzel, Christine A1 - Schauenburg, Gesche A1 - Rapp, Michael A. A1 - Heinzel, Stephan A1 - Granacher, Urs T1 - Age-Related Interference between the Selection of Input-Output Modality Mappings and Postural Control BT - a Pilot Study N2 - Age-related decline in executive functions and postural control due to degenerative processes in the central nervous system have been related to increased fall-risk in old age. Many studies have shown cognitive-postural dual-task interference in old adults, but research on the role of specific executive functions in this context has just begun. In this study, we addressed the question whether postural control is impaired depending on the coordination of concurrent response-selection processes related to the compatibility of input and output modality mappings as compared to impairments related to working-memory load in the comparison of cognitive dual and single tasks. Specifically, we measured total center of pressure (CoP) displacements in healthy female participants aged 19–30 and 66–84 years while they performed different versions of a spatial one-back working memory task during semi-tandem stance on an unstable surface (i.e., balance pad) while standing on a force plate. The specific working-memory tasks comprised: (i) modality compatible single tasks (i.e., visual-manual or auditory-vocal tasks), (ii) modality compatible dual tasks (i.e., visual-manual and auditory-vocal tasks), (iii) modality incompatible single tasks (i.e., visual-vocal or auditory-manual tasks), and (iv) modality incompatible dual tasks (i.e., visual-vocal and auditory-manual tasks). In addition, participants performed the same tasks while sitting. As expected from previous research, old adults showed generally impaired performance under high working-memory load (i.e., dual vs. single one-back task). In addition, modality compatibility affected one-back performance in dual-task but not in single-task conditions with strikingly pronounced impairments in old adults. Notably, the modality incompatible dual task also resulted in a selective increase in total CoP displacements compared to the modality compatible dual task in the old but not in the young participants. These results suggest that in addition to effects of working-memory load, processes related to simultaneously overcoming special linkages between input- and output modalities interfere with postural control in old but not in young female adults. Our preliminary data provide further evidence for the involvement of cognitive control processes in postural tasks. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 322 KW - aging KW - cognitive-postural dual task KW - modality compatibility KW - postural stability KW - working memory Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-395733 ER - TY - GEN A1 - Heinzel, Stephan A1 - Rimpel, Jérôme A1 - Stelzel, Christine A1 - Rapp, Michael A. T1 - Transfer Effects to a Multimodal Dual-Task after Working Memory Training and Associated Neural Correlates in Older Adults BT - A Pilot Study N2 - Working memory (WM) performance declines with age. However, several studies have shown that WM training may lead to performance increases not only in the trained task, but also in untrained cognitive transfer tasks. It has been suggested that transfer effects occur if training task and transfer task share specific processing components that are supposedly processed in the same brain areas. In the current study, we investigated whether single-task WM training and training-related alterations in neural activity might support performance in a dual-task setting, thus assessing transfer effects to higher-order control processes in the context of dual-task coordination. A sample of older adults (age 60–72) was assigned to either a training or control group. The training group participated in 12 sessions of an adaptive n-back training. At pre and post-measurement, a multimodal dual-task was performed in all participants to assess transfer effects. This task consisted of two simultaneous delayed match to sample WM tasks using two different stimulus modalities (visual and auditory) that were performed either in isolation (single-task) or in conjunction (dual-task). A subgroup also participated in functional magnetic resonance imaging (fMRI) during the performance of the n-back task before and after training. While no transfer to single-task performance was found, dual-task costs in both the visual modality (p < 0.05) and the auditory modality (p < 0.05) decreased at post-measurement in the training but not in the control group. In the fMRI subgroup of the training participants, neural activity changes in left dorsolateral prefrontal cortex (DLPFC) during one-back predicted post-training auditory dual-task costs, while neural activity changes in right DLPFC during three-back predicted visual dual-task costs. Results might indicate an improvement in central executive processing that could facilitate both WM and dual-task coordination. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 343 KW - aging KW - cognitive training KW - dual-task KW - fMRI KW - modality KW - neuroimaging KW - transfer KW - working memory Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-401921 ER - TY - GEN A1 - Bohlken, Jens A1 - Jacob, Louis A1 - Schaum, Peter A1 - Rapp, Michael A. A1 - Kostev, Karel T1 - Hip fracture risk in patients with dementia in German primary care practices T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - The aim was to analyze the risk of hip fracture in German primary care patients with dementia. This study included patients aged 65-90 from 1072 primary care practices who were first diagnosed with dementia between 2010 and 2013. Controls were matched (1:1) to cases for age, sex, and type of health insurance. The primary outcome was the diagnosis of hip fracture during the three-year follow-up period. A total of 53,156 dementia patients and 53,156 controls were included. A total of 5.3% of patients and 0.7% of controls displayed hip fracture after three years. Hip fracture occurred more frequently in dementia subjects living in nursing homes than in those living at home (9.2% versus 4.3%). Dementia, residence in nursing homes, and osteoporosis were risk factors for fracture development. Antidementia, antipsychotic, and antidepressant drugs generally had no significant impact on hip fracture risk when prescribed for less than six months. Dementia increased hip fracture risk in German primary care practices. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 395 KW - hip fracture KW - dementia KW - nursing homes KW - osteoporosis KW - risk factors Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-404526 IS - 395 ER - TY - GEN A1 - Zibulski, Romy A1 - Wesener, Felix A1 - Wilkes, Heinz A1 - Plessen, Birgit A1 - Pestryakova, Luidmila Agafyevna A1 - Herzschuh, Ulrike T1 - C / N ratio, stable isotope (δ 13 C, δ 15 N), and n-alkane patterns of brown mosses along hydrological gradients of low-centred polygons of the Siberian Arctic T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Mosses are a major component of the arctic vegetation, particularly in wetlands. We present C / N atomic ratio, delta C-13 and delta N-15 data of 400 brown-moss samples belonging to 10 species that were collected along hydrological gradients within polygonal mires located on the southern Taymyr Peninsula and the Lena River delta in northern Siberia. Additionally, n-alkane patterns of six of these species (16 samples) were investigated. The aim of the study is to see whether the inter-and intraspecific differences in C / N, isotopic compositions and n-alkanes are indicative of habitat, particularly with respect to water level. Overall, we find high variability in all investigated parameters for two different moisture-related groups of moss species. The C / N ratios range between 11 and 53 (median: 32) and show large variations at the intraspecific level. However, species preferring a dry habitat (xero-mesophilic mosses) show higher C / N ratios than those preferring a wet habitat (meso-hygrophilic mosses). The delta C-13 values range between 37.0 and 22.5% (median D 27.8 %). The delta N-15 values range between 6.6 and C 1.7%(median D 2.2 %). We find differences in delta C-13 and delta N-15 compositions between both habitat types. For some species of the meso-hygrophilic group, we suggest that a relationship between the individ-ual habitat water level and isotopic composition can be inferred as a function of microbial symbiosis. The n-alkane distribution also shows differences primarily between xeromesophilic and meso-hygrophilic mosses, i. e. having a dominance of n-alkanes with long (n-C29, n-C31 /and intermediate (n-C25 /chain lengths, respectively. Overall, our results reveal that C / N ratios, isotopic signals and n-alkanes of studied brown-moss taxa from polygonal wetlands are characteristic of their habitat. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 672 KW - atmospheric nitrogen deposition KW - Lena River delta KW - free amino-acids KW - ombrotrophic peat KW - carbon isotopes KW - aquatic macrophytes KW - methane oxidation KW - organic matter KW - soil-nitrogen KW - plants Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-417104 SN - 1866-8372 IS - 672 ER - TY - GEN A1 - Jackisch, Conrad A1 - Angermann, Lisa A1 - Allroggen, Niklas A1 - Sprenger, Matthias A1 - Blume, Theresa A1 - Tronicke, Jens A1 - Zehe, Erwin T1 - Form and function in hillslope hydrology BT - in situ imaging and characterization of flow-relevant structures T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The study deals with the identification and characterization of rapid subsurface flow structures through pedo- and geo-physical measurements and irrigation experiments at the point, plot and hillslope scale. Our investigation of flow-relevant structures and hydrological responses refers to the general interplay of form and function, respectively. To obtain a holistic picture of the subsurface, a large set of different laboratory, exploratory and experimental methods was used at the different scales. For exploration these methods included drilled soil core profiles, in situ measurements of infiltration capacity and saturated hydraulic conductivity, and laboratory analyses of soil water retention and saturated hydraulic conductivity. The irrigation experiments at the plot scale were monitored through a combination of dye tracer, salt tracer, soil moisture dynamics, and 3-D time-lapse ground penetrating radar (GPR) methods. At the hillslope scale the subsurface was explored by a 3-D GPR survey. A natural storm event and an irrigation experiment were monitored by a dense network of soil moisture observations and a cascade of 2-D time-lapse GPR "trenches". We show that the shift between activated and non-activated state of the flow paths is needed to distinguish structures from overall heterogeneity. Pedo-physical analyses of point-scale samples are the basis for sub-scale structure inference. At the plot and hillslope scale 3-D and 2-D time-lapse GPR applications are successfully employed as non-invasive means to image subsurface response patterns and to identify flow-relevant paths. Tracer recovery and soil water responses from irrigation experiments deliver a consistent estimate of response velocities. The combined observation of form and function under active conditions provides the means to localize and characterize the structures (this study) and the hydrological processes (companion study Angermann et al., 2017, this issue). T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 665 KW - Ground Penetrating Radar KW - preferential flow KW - solute transport KW - Catchment Hydrology KW - multiple scales KW - soil moisture KW - water content KW - tracer KW - field KW - model Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-419188 SN - 1866-8372 IS - 665 ER - TY - GEN A1 - Angermann, Lisa A1 - Jackisch, Conrad A1 - Allroggen, Niklas A1 - Sprenger, Matthias A1 - Zehe, Erwin A1 - Tronicke, Jens A1 - Weiler, Markus A1 - Blume, Theresa T1 - Form and function in hillslope hydrology BT - characterization of subsurface flow based on response observations T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The phrase form and function was established in architecture and biology and refers to the idea that form and functionality are closely correlated, influence each other, and co-evolve. We suggest transferring this idea to hydrological systems to separate and analyze their two main characteristics: their form, which is equivalent to the spatial structure and static properties, and their function, equivalent to internal responses and hydrological behavior. While this approach is not particularly new to hydrological field research, we want to employ this concept to explicitly pursue the question of what information is most advantageous to understand a hydrological system. We applied this concept to subsurface flow within a hillslope, with a methodological focus on function: we conducted observations during a natural storm event and followed this with a hillslope-scale irrigation experiment. The results are used to infer hydrological processes of the monitored system. Based on these findings, the explanatory power and conclusiveness of the data are discussed. The measurements included basic hydrological monitoring methods, like piezometers, soil moisture, and discharge measurements. These were accompanied by isotope sampling and a novel application of 2-D time-lapse GPR (ground-penetrating radar). The main finding regarding the processes in the hillslope was that preferential flow paths were established quickly, despite unsaturated conditions. These flow paths also caused a detectable signal in the catchment response following a natural rainfall event, showing that these processes are relevant also at the catchment scale. Thus, we conclude that response observations (dynamics and patterns, i.e., indicators of function) were well suited to describing processes at the observational scale. Especially the use of 2-D time-lapse GPR measurements, providing detailed subsurface response patterns, as well as the combination of stream-centered and hillslope-centered approaches, allowed us to link processes and put them in a larger context. Transfer to other scales beyond observational scale and generalizations, however, rely on the knowledge of structures (form) and remain speculative. The complementary approach with a methodological focus on form (i.e., structure exploration) is presented and discussed in the companion paper by Jackisch et al. (2017). T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 658 KW - ground-penetrating radar KW - preferential flow KW - water-flow KW - runoff generation KW - vadose zone KW - catchment KW - scale KW - tracer KW - time KW - pore Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-419161 SN - 1866-8372 IS - 658 ER - TY - GEN A1 - Hirschmueller, Anja A1 - Baur, Heiner A1 - Braun, Sepp A1 - Kreuz, Peter C. A1 - Suedkamp, Norbert P A1 - Niemeyer, Philipp T1 - Rehabilitation after autologous chondrocyte implantation for isolated cartilage defects of the knee N2 - Autologous chondrocyte implantation for treatment of isolated cartilage defects of the knee has become well established. Although various publications report technical modifications, clinical results, and cell-related issues, little is known about appropriate and optimal rehabilitation after autologous chondrocyte implantation. This article reviews the literature on rehabilitation after autologous chondrocyte implantation and presents a rehabilitation protocol that has been developed considering the best available evidence and has been successfully used for several years in a large number of patients who underwent autologous chondrocyte implantation for cartilage defects of the knee. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 367 KW - autologous chondrocyte implantation KW - cartilage repair KW - cartilage defect KW - cell transplantation KW - knee joint KW - rehabilitation Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-403170 ER - TY - GEN A1 - Müller, Juliane A1 - Engel, Tilman A1 - Müller, Steffen A1 - Stoll, Josefine A1 - Baur, Heiner A1 - Mayer, Frank T1 - Effects of sudden walking perturbations on neuromuscular reflex activity and three-dimensional motion of the trunk in healthy controls and back pain symptomatic subjects N2 - Background Back pain patients (BPP) show delayed muscle onset, increased co-contractions, and variability as response to quasi-static sudden trunk loading in comparison to healthy controls (H). However, it is unclear whether these results can validly be transferred to suddenly applied walking perturbations, an automated but more functional and complex movement pattern. There is an evident need to develop research-based strategies for the rehabilitation of back pain. Therefore, the investigation of differences in trunk stability between H and BPP in functional movements is of primary interest in order to define suitable intervention regimes. The purpose of this study was to analyse neuromuscular reflex activity as well as three-dimensional trunk kinematics between H and BPP during walking perturbations. Methods Eighty H (31m/49f;29±9yrs;174±10cm;71±13kg) and 14 BPP (6m/8f;30±8yrs;171±10cm;67±14kg) walked (1m/s) on a split-belt treadmill while 15 right-sided perturbations (belt decelerating, 40m/s2, 50ms duration; 200ms after heel contact) were randomly applied. Trunk muscle activity was assessed using a 12-lead EMG set-up. Trunk kinematics were measured using a 3-segment-model consisting of 12 markers (upper thoracic (UTA), lower thoracic (LTA), lumbar area (LA)). EMG-RMS ([%],0-200ms after perturbation) was calculated and normalized to the RMS of unperturbed gait. Latency (TON;ms) and time to maximum activity (TMAX;ms) were analysed. Total motion amplitude (ROM;[°]) and mean angle (Amean;[°]) for extension-flexion, lateral flexion and rotation were calculated (whole stride cycle; 0-200ms after perturbation) for each of the three segments during unperturbed and perturbed gait. For ROM only, perturbed was normalized to unperturbed step [%] for the whole stride as well as the 200ms after perturbation. Data were analysed descriptively followed by a student´s t-test to account for group differences. Co-contraction was analyzed between ventral and dorsal muscles (V:R) as well as side right:side left ratio (Sright:Sleft). The coefficient of variation (CV;%) was calculated (EMG-RMS;ROM) to evaluate variability between the 15 perturbations for all groups. With respect to unequal distribution of participants to groups, an additional matched-group analysis was conducted. Fourteen healthy controls out of group H were sex-, age- and anthropometrically matched (group Hmatched) to the BPP. Results No group differences were observed for EMG-RMS or CV analysis (EMG/ROM) (p>0.025). Co-contraction analysis revealed no differences for V:R and Srigth:Sleft between the groups (p>0.025). BPP showed an increased TON and TMAX, being significant for Mm. rectus abdominus (p = 0.019) and erector spinae T9/L3 (p = 0.005/p = 0.015). ROM analysis over the unperturbed stride cycle revealed no differences between groups (p>0.025). Normalization of perturbed to unperturbed step lead to significant differences for the lumbar segment (LA) in lateral flexion with BPP showing higher normalized ROM compared to Hmatched (p = 0.02). BPP showed a significant higher flexed posture (UTA (p = 0.02); LTA (p = 0.004)) during normal walking (Amean). Trunk posture (Amean) during perturbation showed higher trunk extension values in LTA segments for H/Hmatched compared to BPP (p = 0.003). Matched group (BPP vs. Hmatched) analysis did not show any systematic changes of all results between groups. Conclusion BPP present impaired muscle response times and trunk posture, especially in the sagittal and transversal planes, compared to H. This could indicate reduced trunk stability and higher loading during gait perturbations. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 317 Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-394931 ER - TY - GEN A1 - Wahmkow, Gunnar A1 - Cassel, Michael A1 - Mayer, Frank A1 - Baur, Heiner T1 - Effects of different medial arch support heights on rearfoot kinematics N2 - Background Foot orthoses are usually assumed to be effective by optimizing mechanically dynamic rearfoot configuration. However, the effect from a foot orthosis on kinematics that has been demonstrated scientifically has only been marginal. The aim of this study was to examine the effect of different heights in medial arch-supported foot orthoses on rear foot motion during gait. Methods Nineteen asymptomatic runners (36±11years, 180±5cm, 79±10kg; 41±22km/week) participated in the study. Trials were recorded at 3.1 mph (5 km/h) on a treadmill. Athletes walked barefoot and with 4 different not customized medial arch-supported foot orthoses of various arch heights (N:0 mm, M:30 mm, H:35 mm, E:40mm). Six infrared cameras and the `Oxford Foot Model´ were used to capture motion. The average stride in each condition was calculated from 50 gait cycles per condition. Eversion excursion and internal tibia rotation were analyzed. Descriptive statistics included calculating the mean ± SD and 95% CIs. Group differences by condition were analyzed by one factor (foot orthoses) repeated measures ANOVA (α = 0.05). Results Eversion excursion revealed the lowest values for N and highest for H (B:4.6°±2.2°; 95% CI [3.1;6.2]/N:4.0°±1.7°; [2.9;5.2]/M:5.2°±2.6°; [3.6;6.8]/H:6.2°±3.3°; [4.0;8.5]/E:5.1°±3.5°; [2.8;7.5]) (p>0.05). Range of internal tibia rotation was lowest with orthosis H and highest with E (B:13.3°±3.2°; 95% CI [11.0;15.6]/N:14.5°±7.2°; [9.2;19.6]/M:13.8°±5.0°; [10.8;16.8]/H:12.3°±4.3°; [9.0;15.6]/E:14.9°±5.0°; [11.5;18.3]) (p>0.05). Differences between conditions were small and the intrasubject variation high. Conclusion Our results indicate that different arch support heights have no systematic effect on eversion excursion or the range of internal tibia rotation and therefore might not exert a crucial influence on rear foot alignment during gait. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 348 Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-402934 ER - TY - GEN A1 - Lomadze, Nino A1 - Kopyshev, Alexey A1 - Bargheer, Matias A1 - Wollgarten, Markus A1 - Santer, Svetlana T1 - Mass production of polymer nanowires filled with metal nanoparticles N2 - Despite the ongoing progress in nanotechnology and its applications, the development of strategies for connecting nano-scale systems to micro- or macroscale elements is hampered by the lack of structural components that have both, nano- and macroscale dimensions. The production of nano-scale wires with macroscale length is one of the most interesting challenges here. There are a lot of strategies to fabricate long nanoscopic stripes made of metals, polymers or ceramics but none is suitable for mass production of ordered and dense arrangements of wires at large numbers. In this paper, we report on a technique for producing arrays of ordered, flexible and free-standing polymer nano-wires filled with different types of nano-particles. The process utilizes the strong response of photosensitive polymer brushes to irradiation with UV-interference patterns, resulting in a substantial mass redistribution of the polymer material along with local rupturing of polymer chains. The chains can wind up in wires of nano-scale thickness and a length of up to several centimeters. When dispersing nano-particles within the film, the final arrangement is similar to a core-shell geometry with mainly nano-particles found in the core region and the polymer forming a dielectric jacket. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 387 Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-402712 ER - TY - GEN A1 - Reil, Daniela A1 - Rosenfeld, Ulrike A1 - Imholt, Christian A1 - Schmidt, Sabrina A1 - Ulrich, Rainer G. A1 - Eccard, Jana A1 - Jacob, Jens T1 - Puumala hantavirus infections in bank vole populations BT - host and virus dynamics in Central Europe T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Background In Europe, bank voles (Myodes glareolus) are widely distributed and can transmit Puumala virus (PUUV) to humans, which causes a mild to moderate form of haemorrhagic fever with renal syndrome, called nephropathia epidemica. Uncovering the link between host and virus dynamics can help to prevent human PUUV infections in the future. Bank voles were live trapped three times a year in 2010–2013 in three woodland plots in each of four regions in Germany. Bank vole population density was estimated and blood samples collected to detect PUUV specific antibodies. Results We demonstrated that fluctuation of PUUV seroprevalence is dependent not only on multi-annual but also on seasonal dynamics of rodent host abundance. Moreover, PUUV infection might affect host fitness, because seropositive individuals survived better from spring to summer than uninfected bank voles. Individual space use was independent of PUUV infections. Conclusions Our study provides robust estimations of relevant patterns and processes of the dynamics of PUUV and its rodent host in Central Europe, which are highly important for the future development of predictive models for human hantavirus infection risk. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 957 KW - Myodes glareolus KW - population dynamics KW - Puumala virus seroprevalence KW - space use KW - survival Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-431232 SN - 1866-8372 IS - 957 ER - TY - GEN A1 - Schrön, Martin A1 - Köhli, Markus A1 - Scheiffele, Lena A1 - Iwema, Joost A1 - Bogena, Heye R. A1 - Lv, Ling A1 - Martini, Edoardo A1 - Baroni, Gabriele A1 - Rosolem, Rafael A1 - Weimar, Jannis A1 - Mai, Juliane A1 - Cuntz, Matthias A1 - Rebmann, Corinna A1 - Oswald, Sascha A1 - Dietrich, Peter A1 - Schmidt, Ulrich A1 - Zacharias, Steffen T1 - Improving calibration and validation of cosmic-ray neutron sensors in the light of spatial sensitivity T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - In the last few years the method of cosmic-ray neutron sensing (CRNS) has gained popularity among hydrologists, physicists, and land-surface modelers. The sensor provides continuous soil moisture data, averaged over several hectares and tens of decimeters in depth. However, the signal still may contain unidentified features of hydrological processes, and many calibration datasets are often required in order to find reliable relations between neutron intensity and water dynamics. Recent insights into environmental neutrons accurately described the spatial sensitivity of the sensor and thus allowed one to quantify the contribution of individual sample locations to the CRNS signal. Consequently, data points of calibration and validation datasets are suggested to be averaged using a more physically based weighting approach. In this work, a revised sensitivity function is used to calculate weighted averages of point data. The function is different from the simple exponential convention by the extraordinary sensitivity to the first few meters around the probe, and by dependencies on air pressure, air humidity, soil moisture, and vegetation. The approach is extensively tested at six distinct monitoring sites: two sites with multiple calibration datasets and four sites with continuous time series datasets. In all cases, the revised averaging method improved the performance of the CRNS products. The revised approach further helped to reveal hidden hydrological processes which otherwise remained unexplained in the data or were lost in the process of overcalibration. The presented weighting approach increases the overall accuracy of CRNS products and will have an impact on all their applications in agriculture, hydrology, and modeling. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 636 KW - forested headwater catchment KW - moisture observing system KW - soil-water content KW - parameterization methods KW - scale KW - field KW - dynamics KW - observatories KW - networks Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-419134 IS - 636 SP - 5009 EP - 5030 ER -