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1
Ewen, Martin [Verfasser]. "On the stability of portfolio risk - An analysis of the impact of portfolio size and risk based fund classification / Martin Ewen." Trier : Universität Trier, 2018. http://d-nb.info/1197807926/34.
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Löwe, Albrecht, Marek Hauptmann, and Jens-Peter Majschak. "The Effect of Ultrasonic Oscillation on the Quality of 3D Shapes During Deep-Drawing of Paperboard." NC State University, 2017. https://tud.qucosa.de/id/qucosa%3A30657.
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In this publication, the ultrasonic-assisted deep-drawing of fiber-based materials, whose implementation was presented in Löwe et al. (2016), was studied in detail. Methods were developed for measuring the properties of deep-drawn cups, including cup stability, shape deviation, and surface quality. The relationship between these properties and the process parameters were determined with a design of experiment, which allows the user to adjust the cup properties in order to optimize them.
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Neu, Silke, Jörg Schaller, and E. Gert Dudel. "Silicon availability modifies nutrient use efficiency and content, C:N:P stoichiometry, and productivity of winter wheat (Triticum aestivum L.)." Nature Publishing Group, 2016. https://tud.qucosa.de/id/qucosa%3A30213.
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Silicon (Si) is known as beneficial element for graminaceous plants. The importance of Si for plant functioning of cereals was recently emphasized. However, about the effect of Si availability on biomass production, grain yield, nutrient status and nutrient use efficiency for wheat (Triticum aestivum L.), as one of the most important crop plants worldwide, less is known so far. Consequently, we assessed the effect of a broad range of supply levels of amorphous SiO2 on wheat plant performance. Our results revealed that Si is readily taken up and accumulated basically in aboveground vegetative organs. Carbon (C) and phosphorus (P) status of plants were altered in response to varying Si supply. In bulk straw biomass C concentration decreased with increasing Si supply, while P concentration increased from slight limitation towards optimal nutrition. Thereby, aboveground biomass production increased at low to medium supply levels of silica whereas grain yield increased at medium supply level only. Nutrient use efficiency was improved by Si insofar that biomass production was enhanced at constant nitrogen (N) status of substrate and plants. Consequently, our findings imply fundamental influences of Si on C turnover, P availability and nitrogen use efficiency for wheat as a major staple crop.
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Stockigt, Janice B. "Vivaldi entdecken." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2006. http://nbn-resolving.de/urn:nbn:de:swb:14-1160131889818-06192.
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Wie erwähnt (SLUB-Kurier 2005/4), hat die Musikhistorikerin Dr. Janice B. Stockigt, Mitglied der Australian Academy of the Humanities und der Faculty of Music der University of Melbourne (Kurzporträt in SLUB-Kurier 2001/4), letztes Jahr im historischen Musikalienbestand der SLUB den wohl wichtigsten Vivaldi-Fund seit 75 Jahren gemacht. Im Folgenden informiert Jan Stockigt selber über die Genese ihrer Entdeckung. Im März 2006 war der Bericht ertmals in Symposium The Newsletter of the Australian Academy of the Humantities erschienen. Die Übersetzung aus dem Englischen fertigte K.W. Geck an.
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Fichtner, Andreas, David I. Forrester, Werner Härdtle, Knut Sturm, and Oheimb Goddert von. "Facilitative-Competitive Interactions in an Old-Growth Forest: The Importance of Large-Diameter Trees as Benefactors and Stimulators for Forest Community Assembly." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-173653.
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The role of competition in tree communities is increasingly well understood, while little is known about the patterns and mechanisms of the interplay between above- and belowground competition in tree communities. This knowledge, however, is crucial for a better understanding of community dynamics and developing adaptive near-natural management strategies. We assessed neighbourhood interactions in an unmanaged old-growth European beech (Fagus sylvatica) forest by quantifying variation in the intensity of above- (shading) and belowground competition (crowding) among dominant and co-dominant canopy beech trees during tree maturation. Shading had on average a much larger impact on radial growth than crowding and the sensitivity to changes in competitive conditions was lowest for crowding effects. We found that each mode of competition reduced the effect of the other. Increasing crowding reduced the negative effect of shading, and at high levels of shading, crowding actually had a facilitative effect and increased growth. Our study demonstrates that complementarity in above- and belowground processes enable F. sylvatica to alter resource acquisition strategies, thus optimising tree radial growth. As a result, competition seemed to become less important in stands with a high growing stock and tree communities with a long continuity of anthropogenic undisturbed population dynamics. We suggest that growth rates
do not exclusively depend on the density of potential competitors at the intraspecific level, but on the conspecific aggregation of large-diameter trees and their functional role for regulating biotic filtering processes. This finding highlights the potential importance of the rarely examined relationship between the spatial aggregation pattern of large-diameter trees and the outcome of neighbourhood interactions, which may be central to community dynamics and the related forest ecosystem services.
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Nawroth, Jonas F., Claudia Neisser, Artur Erbe, and Rainer Jordan. "Nanopatterned polymer brushes by reactive writing." Royal Society of Chemistry, 2016. https://tud.qucosa.de/id/qucosa%3A29980.
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Polymer brush patterns were prepared by a combination of electron beam induced damage in self-assembled monolayers (SAMs), creating a stable carbonaceous deposit, and consecutive self-initiated photografting and photopolymerization (SIPGP). This newly applied technique, reactive writing (RW), is investigated with 1H,1H,2H,2H-perfluorooctyltriethoxysilane SAM (PF-SAM) on silicon oxide, which, when modified by RW, can be selectively functionalized by SIPGP. With the monomer N,N-dimethylaminoethyl methacrylate (DMAEMA), we demonstrate the straightforward formation of polymer brush gradients and single polymer lines of sub-100 nm lateral dimensions, with high contrast to the PF-SAM background. The lithography parameters acceleration voltage, irradiation dose, beam current and dwell time were systematically varied to identify the optimal conditions for the maximum conversion of the SAM into a carbonaceous deposit. The results of this approach were compared to patterns prepared by carbon templating (CT) under analogous conditions, revealing a dwell time dependency, which differs from earlier reports. This new technique expands the range of CT by giving the opportunity to not only vary the chemistry of the created polymer patterns with monomer choice but also vary the chemistry of the surrounding substrate.
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Donath, Maximillian, Felix Hennersdorf, and Jan J. Weigand. "Recent highlights in mixed-coordinate oligophosphorus chemistry." Royal Society of Chemistry, 2016. https://tud.qucosa.de/id/qucosa%3A30076.
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This review aims to highlight and comprehensively summarize recent developments in the field of mixed-coordinate phosphorus chemistry. Particular attention is focused on the synthetic approaches to compounds containing at least two directly bonded phosphorus atoms in different coordination environments and their unexpected properties that are derived from spectroscopic and crystallographic data. Novel substance classes are discussed in order to supplement previous reviews about mixed-coordinate phosphorus compounds.
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Kensche, Anna, Sandra Pötschke, Christian Hannig, Gert Richter, Wiebke Hoth-Hannig, and Matthias Hannig. "Influence of Calcium Phosphate and Apatite Containing Products on Enamel Erosion." Hindawi, 2016. https://tud.qucosa.de/id/qucosa%3A30115.
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For the purpose of erosion prevention the present study aimed to compare the efficacy of two biomimetic products and a fluoride solution to optimize the protective properties of the pellicle. After 1 min of in situ pellicle formation on bovine enamel slabs, 8 subjects adopted CPP-ACP (GC Tooth Mousse), a mouthwash with hydroxyapatite microclusters (Biorepair), or a fluoride based mouthwash (elmex Kariesschutz) for 1 min each. Afterwards, samples were exposed in the oral cavity for 28 min. Native enamel slabs and slabs exposed to the oral cavity for 30 min without any rinse served as controls. After oral exposure, slabs were incubated in HCl (pH values 2, 2.3, and 3) for 120 s and kinetics of calcium and phosphate release were measured photometrically; representative samples were evaluated by SEM and TEM. The physiological pellicle reduced demineralization at all pH values; the protective effect was enhanced by fluoride. The biomimetic materials also reduced ion release but their effect was less pronounced. SEM indicated no layer formation after use of the different products. However, TEM confirmed the potential accumulation of mineral components at the pellicle surface. The tested products improve the protective properties of the in situ pellicle but not as effectively as fluorides.
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Baldow, Christoph, Sebastian Salentin, Michael Schroeder, Ingo Roeder, and Ingmar Glauche. "MAGPIE: Simplifying access and execution of computational models in the life sciences." Public Library of Science, 2017. https://tud.qucosa.de/id/qucosa%3A30818.
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Over the past decades, quantitative methods linking theory and observation became increasingly important in many areas of life science. Subsequently, a large number of mathematical and computational models has been developed. The BioModels database alone lists more than 140,000 Systems Biology Markup Language (SBML) models. However, while the exchange within specific model classes has been supported by standardisation and database efforts, the generic application and especially the re-use of models is still limited by practical issues such as easy and straight forward model execution. MAGPIE, a Modeling and Analysis Generic Platform with Integrated Evaluation, closes this gap by providing a software platform for both, publishing and executing computational models without restrictions on the programming language, thereby combining a maximum on flexibility for programmers with easy handling for non-technical users. MAGPIE goes beyond classical SBML platforms by including all models, independent of the underlying programming language, ranging from simple script models to complex data integration and computations. We demonstrate the versatility of MAGPIE using four prototypic example cases. We also outline the potential of MAGPIE to improve transparency and reproducibility of computational models in life sciences. A demo server is available at magpie.imb.medizin.tu-dresden.de.
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Wieckiewicz, Mieszko, Eric Wolf, Gert Richter, Heike Meissner, and Klaus Boening. "New Concept of Polymethyl Methacrylate (PMMA) and Polyethylene Terephthalate (PET) Surface Coating by Chitosan." Molecular Diversity Preservation International (MDPI), 2016. https://tud.qucosa.de/id/qucosa%3A30051.
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Chitosan is known for its hemostatic and antimicrobial properties and might be useful for temporary coating of removable dentures or intraoral splints to control bleeding after oral surgery or as a supportive treatment in denture stomatitis. This study investigated a new method to adhere chitosan to polymethyl methacrylate (PMMA) and polyethylene terephthalate (PET). There were 70 cylindrical specimens made from PMMA and 70 from PET (13 mm diameter, 6 mm thickness). The materials with ten specimens each were sandblasted at 2.8 or 4.0 bar with aluminum oxide 110 μm or/and aluminum oxide coated with silica. After sandblasting, all specimens were coated with a 2% or 4% acetic chitosan solution with a thickness of 1 mm. Then the specimens were dried for 120 min at 45 °C. The precipitated chitosan was neutralized with 1 mol NaOH. After neutralization, all specimens underwent abrasion tests using the tooth-brushing simulator with soft brushes (load 2N, 2 cycles/s, 32 °C, 3000 and 30,000 cycles). After each run, the specimen surfaces were analyzed for areas of remaining chitosan by digital planimetry under a light microscope. The best chitosan adhesion was found after sandblasting with aluminum oxide coated with silica (U-Test, p < 0.05) in both the PMMA and the PET groups. Hence, with relatively simple technology, a reliable bond of chitosan to PMMA and PET could be achieved.
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Wichmann, Susann, Stefan R. Bornstein, Thomas Lorenz, and Katja Petrowski. "Stress hormone response to the DEX-CRH test and its relation to psychotherapy outcome in panic disorder patients with and without agoraphobia." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-233439.
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This study tested whether the hormonal stress response to the DEX-CRH test may be predictive of the psychotherapy success for panic disorder (PD). Thirty-four patients diagnosed either with agoraphobia with PD or PD without agoraphobia were subjected to cognitive behavioural therapy (CBT). Patients (pre-therapy) and healthy volunteers were exposed to the DEX-CRH test. Blood samples were taken for cortisol and adrenocorticotropic hormone (ACTH) assessment. Established panic-specific questionnaires were handed out for the pre-therapy and post-therapy evaluation of disease severity (with reference to panic beliefs and agoraphobic cognitions, fear of bodily sensations, agoraphobic avoidance behaviour). Repeated measures ANCOVA were conducted for the analysis of the pre-therapy hormonal response, and Pearson\'s correlation analysis to test for associations with the psychotherapy outcome. Data analyses revealed large effect sizes for CBT in the clinical measures (η2 ≥ 0.321), main effects of time for cortisol and ACTH with no differences between both groups, and significant associations between cortisol release and agoraphobic cognitions for the patients. PD diagnosis had no impact on the hormonal response. However, those patients with higher cortisol release showed less improvement after CBT (significantly for agoraphobic cognitions). Clinical implications of these findings are the prediction of the therapy success from a potential endocrine correlate whose persistency (if assessed repeatedly) during the treatment may predict (non-)response to the current treatment, possibly representing a decision support for a change in treatment to avoid the continuation of an inefficient treatment.
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Bluschke, Annet, Jacqueline Schuster, Veit Roessner, and Christian Beste. "Neurophysiological mechanisms of interval timing dissociate inattentive and combined ADHD subtypes." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-234834.
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It is far from conclusive what distinguishes the inattentive (ADD) and the combined (ADHD-C) subtype of ADHD on the neuronal level. Theoretical considerations suggest that especially interval timing processes may dissociate these subtypes from each other. Combining high-density EEG recordings with source localization analyses, we examine whether there are ADHD-subtype specific modulations of neurophysiological processes subserving interval timing in matched groups of ADD (n = 16), ADHD-C (n = 16) and controls (n = 16). Patients with ADD and ADHD-C show deficits in interval timing, which was correlated with the degree of inattention in ADD patients. Compared to healthy controls, patients with ADHD-C display a somewhat weaker, yet consistent response preparation process (contingent negative variation, CNV). In patients with ADD, the early CNV is interrupted, indicating an oscillatory disruption of the interval timing process. This is associated with activations in the supplemental motor areas and the middle frontal gyrus. Patients with ADD display adequate feedback learning mechanisms (feedback-related negativity, FRN), which is not the case in patients with ADHD-C. The results suggest that altered pacemaker-accumulation processes in medial frontal structures distinguish the ADD from the ADHD-C subtype. Particularly in patients with ADD phasic interruptions of preparatory neurophysiological processes are evident, making this a possible diagnostic feature.
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Stock, Ann-Kathrin, Krutika Gohil, René J. Huster, and Christian Beste. "On the effects of multimodal information integration in multitasking." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-230405.
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There have recently been considerable advances in our understanding of the neuronal mechanisms underlying multitasking, but the role of multimodal integration for this faculty has remained rather unclear. We examined this issue by comparing different modality combinations in a multitasking (stop-change) paradigm. In-depth neurophysiological analyses of event-related potentials (ERPs) were conducted to complement the obtained behavioral data. Specifically, we applied signal decomposition using second order blind identification (SOBI) to the multi-subject ERP data and source localization. We found that both general multimodal information integration and modality-specific aspects (potentially related to task difficulty) modulate behavioral performance and associated neurophysiological correlates. Simultaneous multimodal input generally increased early attentional processing of visual stimuli (i.e. P1 and N1 amplitudes) as well as measures of cognitive effort and conflict (i.e. central P3 amplitudes). Yet, tactile-visual input caused larger impairments in multitasking than audio-visual input. General aspects of multimodal information integration modulated the activity in the premotor cortex (BA 6) as well as different visual association areas concerned with the integration of visual information with input from other modalities (BA 19, BA 21, BA 37). On top of this, differences in the specific combination of modalities also affected performance and measures of conflict/effort originating in prefrontal regions (BA 6).
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Bohlandt, Florian Martin. "Single manager hedge funds - aspects of classification and diversification." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85859.
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Thesis (PhD)--Stellenbosch University, 2013.A persistent problem for hedge fund researchers presents itself in the form of inconsistent and diverse style classifications within and across database providers. For this paper, single-manager hedge funds from the Hedge Fund Research (HFR) and Hedgefund.Net (HFN) databases were classified on the basis of a common factor, extracted using the factor axis methodology. It was assumed that the returns of all sample hedge funds are attributable to a common factor that is shared across hedge funds within one classification, and a specific factor that is unique to a particular hedge fund. In contrast to earlier research and the application of principal component analysis, factor axis has sought to determine how much of the covariance in the dataset is due to common factors (communality). Factor axis largely ignores the diagonal elements of the covariance matrix and orthogonal factor rotation maximises the covariance between hedge fund return series. In an iterative framework, common factors were extracted until all return series were described by one common and one specific factor. Prior to factor extraction, the series was tested for autoregressive moving-average processes and the residuals of such models were used in further analysis to improve upon squared correlations as initial factor estimates. The methodology was applied to 120 ten-year rolling estimation windows in the July 1990 to June 2010 timeframe. The results indicate that the number of distinct style classifications is reduced in comparison to the arbitrary self-selected classifications of the databases. Single manager hedge funds were grouped in portfolios on the basis of the common factor they share. In contrast to other classification methodologies, these common factor portfolios (CFPs) assume that some unspecified individual component of the hedge fund constituents’ returns is diversified away and that single manager hedge funds should be classified according to their common return components. From the CFPs of single manager hedge funds, pure style indices were created to be entered in a multivariate autoregressive framework. For each style index, a Vector Error Correction model (VECM) was estimated to determine the short-term as well as co-integrating relationship of the hedge fund series with the index level series of a stock, bond and commodity proxy. It was postulated that a) in a well-diversified portfolio, the current level of the hedge fund index is independent of the lagged observations from the other asset indices; and b) if the assumptions of the Efficient Market Hypothesis (EMH) hold, it is expected that the predictive power of the model will be low. The analysis was conducted for the July 2000 - June 2010 period. Impulse response tests and variance decomposition revealed that changes in hedge fund index levels are partially induced by changes in the stock, bond and currency markets. Investors are therefore cautioned not to overemphasise the diversification benefits of hedge fund investments. Commodity trading advisors (CTAs) / managed futures, on the other hand, deliver diversification benefits when integrated with an existing portfolio. The results indicated that single manager hedge funds can be reliably classified using the principal factor axis methodology. Continuously re-balanced pure style index representations of these classifications could be used in further analysis. Extensive multivariate analysis revealed that CTAs and macro hedge funds offer superior diversification benefits in the context of existing portfolios. The empirical results are of interest not only to academic researchers, but also practitioners seeking to replicate the methodologies presented.
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Austová, Lucia. "Analysis and classification of hedge funds and hedge strategies." Master's thesis, Vysoká škola ekonomická v Praze, 2008. http://www.nusl.cz/ntk/nusl-9268.
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An objective of my graduation thesis is an analysis of hedge funds and hedge strategies while reflecting the distribution of the investments to right portfolio taking into account the risk. The main aim is to provide clear and consistent classification of whole variety of different hedge styles and strategies. There are plenty of different investment and trading strategies of hedge funds and their classification differs from analyst to analyst and from database to database. The work focuses on finding an alternative consistent classification of hedge funds which will lead to improvement of investment decisions of financial market participants, to effective distribution of the investment portfolio and therefore to elimination of undiversified risks. For the practical analysis I use real data of hedge fund returns of particular relevant time period. I focus on research and description of possible methods of hedge fund classification mentioning their pluses and minuses. After passionate evaluation of each method I have chosen two methods according to which I classify the hedge funds datasets and finally I compare the results of both. The theoretical part of work focuses on definition of hedge funds, hedge styles and strategies, pluses and minuses as well as risk accompanying particular strategy.
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Wallmeier, Malte, Marek Hauptmann, and Jens-Peter Majschak. "The Occurrence of Rupture in Deep-Drawing of Paperboard." NC State University, 2016. https://tud.qucosa.de/id/qucosa%3A30057.
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The production of paperboard packaging components in fast-running machines requires reliability of the production process. Boundaries for the process parameters and constraints for the geometry of the tools require investigation to determine dependable configurations. This paper aimed to investigate the relationships between process parameters, tool geometry, and the occurrence of rupture in the deep-drawing process of paperboard. Different types of ruptures in various phases of the process were distinguished and linked to their specific cause. An extensive experimental investigation with multiple variables of influence was conducted. A logistic regression model was used to describe the experimental data and was statistically validated. The blankholder force was found to be the most influential parameter. Interactions between the parameters blankholder force, punch velocity, and punch diameter were recognized. A high punch velocity can reduce the probability of rupture when the punch diameter is adjusted.
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Schleicher, David, Alexander Tronnier, Hendrik Leopold, Horst Borrmann, and Thomas Strassner. "Unusual dimer formation of cyclometalated ruthenium NHC p-cymene complexes." Royal Society of Chemistry, 2016. https://tud.qucosa.de/id/qucosa%3A30175.
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We present the synthesis and structural characterization of novel ruthenium complexes containing C^C* cyclometalated N-heterocyclic carbene ligands, η6-arene (p-cymene) ligands and one bridging chlorine ion. Complexes of the general formula [Ru(p-cymene)(C^C*)Cl] were prepared via a one-pot synthesis using in situ transmetalation from the correspondent silver NHC complexes. These complexes react with sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaBArF4) to form dinuclear complexes of the general structure [Ru(p-cymene)(C^C*)-μ-Cl-(p-cymene)(C^C*)Ru]+[BArF4]−. Solid-state structures confirm that the pseudo-tetrahedral coordination around the metal center with the η6-ligand aligned perpendicularly to the C^C* ligand and the i-Pr group “atop” is retained in the bimetallic complexes.
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Julich, Dorit, and Karl-Heinz Feger. "Phosphorus in Preferential Flow Pathways of Forest Soils in Germany." Molecular Diversity Preservation International (MDPI), 2016. https://tud.qucosa.de/id/qucosa%3A30202.
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The transport of nutrients in forest soils predominantly occurs along preferential flow pathways (PFP). This study investigated the composition of phosphorus (P) forms in PFPs and soil matrix in several temperate beech forests with contrasting soil P contents in Germany. The PFPs were visualized using dye tracer experiments. Stained and unstained soil was sampled from three profile cuts per plot and analyzed for P fractions. The results show that labile P concentrations were highest in the O-layer and had the same range of values at all sites (240–320 mg·kg−1), although total P (TP) differed considerably (530–2330 mg·kg−1). The ratio of labile P to TP was significantly lower in the P-rich soil compared to the medium and P-poor soils. By contrast, the ratio of moderately labile P to TP was highest at the P-rich site. The shifts in P fractions with soil depth were generally gradual in the P-rich soil, but more abrupt at the others. The contents of labile and moderately labile P clearly differed in PFPs compared to soil matrix, but not statistically significant. The studied soils are characterized by high stone contents with low potential for P sorption. However, indications were found that labile organically bound P accumulates in PFPs such as biopores.
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Więckiewicz, Mieszko, Eric Wolf, Katarzyna Walczak, Heike Meissner, and Klaus Boening. "Chitosan Coating on Silica-Modified Polymethyl Methacrylate for Dental Applications." Molecular Diversity Preservation International (MDPI), 2017. https://tud.qucosa.de/id/qucosa%3A30700.
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Chitosan is a cationic natural polymer that is widely used as a topical dressing in wound management. Temporary coatings of removable denture bases with chitosan might be useful as supportive treatment in oral medicine. The aim of this study was to analyze the thickness, uniformity, and adhesive strength of chitosan coatings on simulated denture bases made from polymethyl methacrylate (PMMA). According to a standardized protocol, 20 PMMA cylinders (13 mm diameter, 5 mm in height) as well as 20 cubes (a = 25 mm) with intaglio U-shaped profiles were manufactured to simulate average sized alveolar ridges. Cylinders as well as cubes were divided into four test series with n = 5 each. After sandblasting with silica-modified alumina, one frontal surface of the PMMA cylinders and the intaglio surfaces of the U-shaped profiles was coated with chitosan acetate solution according to the following protocols: one layer of 2% chitosan acetate solution (test series I), one layer of 4% chitosan acetate solution (test series II), two layers of 2% chitosan acetate solution (test series III), and two layers of 4% chitosan acetate solution (test series IV). After drying and neutralization with NaOH, each cube was cut transversely and the coating thickness across the U-shaped profile assessed with a light microscope. Adhesive strength was evaluated by simulated tooth brushing and the loss of chitosan coating was evaluated qualitatively. Statistical analysis used Friedman ANOVA test for dependent samples and Kruskal-Wallis test for independent samples, post-hoc Dunn’s test (p < 0.05), and binomial test (p = 0.05). The mean chitosan coating thicknesses in the depth of the U-profiles were 71 µm (test series I), 77 µm (test series II), 121 µm (test series III), and 517 µm (test series VI). The thickness continuously decreased with rising angulation of the U-profile side walls. In test series I, the chitosan coating thickness significantly dropped above a 30° angulation of the U-profile side walls. In test series II to IV, the chitosan thickness drop was not statistically significant at angulations of 30° and 60°, but was at 90° angulation of the U-profile side walls. Adhesion strength was rated fair to good and did not differ significantly among the four test series. The coating technique described revealed chitosan layers with overall good adhesion strength but differing thicknesses. Coatings with one or two layers of 4% chitosan acetate solution allowed a relatively uniform chitosan thickness and thus might be usable in oral medicine.
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Freiberg, Alice, Maria Girbig, Ulrike Euler, Julia Scharfe, Albert Nienhaus, Sonja Freitag, and Andreas Seidler. "Influence of the Kinaesthetics care conception during patient handling on the development of musculoskeletal complaints and diseases - A scoping review." BioMed Central, 2016. https://tud.qucosa.de/id/qucosa%3A30133.
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The Kinaesthetics care conception is a nursing approach for patient handling which aims to prevent work-related complaints and diseases. The evidence about the influence of Kinaesthetics on musculoskeletal disorders among persons who handle patients is unclear to date. The purposes of the scoping review are to gain insight into the current state of research regarding the clinical effectiveness of Kinaesthetics (in terms of perceived exertion and musculoskeletal complaints) among persons who handle patients and to identify potential research gaps. A scoping review was conducted. The search strategy comprised a systematic search in electronic databases (MEDLINE, EMBASE, AMED, CINAHL), a hand search, a fast forward search (Web of Science) and a Google scholar-search. The review process was carried out independently by two reviewers. Methodological quality was assessed for all studies using three methodological main categories (reporting quality, internal validity, external validity). Thirteen studies with different study designs were included. Seven studies investigated musculoskeletal complaints and nine studies the perceived exertion of nursing staff. Most studies were of very low methodology. Most studies reported a decrease of musculoskeletal complaints and perceived exertion due to Kinaesthetics. In conclusion, there is only little evidence of very low quality about the effectiveness of Kinaesthetics. Out of the studies it could be assumed that Kinaesthetics may decrease the patient handling related perceived exertion and musculoskeletal pain of persons who handle patients. But an overestimation of these results is likely, due to inadequate methodology of included studies. As a result, no clear recommendations about the effectiveness of the Kinaesthetics care conception can be made yet. Since a research gap was shown, further high quality intervention studies are necessary for clarifying the effectiveness of Kinaesthetics.
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Sinding, Charlotte, François Valadier, Viviana Al-Hassani, Gilles Feron, Anne Tromelin, Ioannis Kontaris, and Thomas Hummel. "New determinants of olfactory habituation." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-227051.
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Habituation is a filter that optimizes the processing of information by our brain in all sensory modalities. It results in an unconscious reduced responsiveness to continuous or repetitive stimulation. In olfaction, the main question is whether habituation works the same way for any odorant or whether we habituate differently to each odorant? In particular, whether chemical, physical or perceptual cues can limit or increase habituation. To test this, the odour intensity of 32 odorants differing in physicochemical characteristics was rated by 58 participants continuously during 120s. Each odorant was delivered at a constant concentration. Results showed odorants differed significantly in habituation, highlighting the multifactoriality of habituation. Additionally habituation was predicted from 15 physico-chemical and perceptual characteristics of the odorants. The analysis highlighted the importance of trigeminality which is highly correlated to intensity and pleasantness. The vapour pressure, the molecular weight, the Odor Activity Value (OAV) and the number of double bonds mostly contributed to the modulation of habituation. Moreover, length of the carbon chain, number of conformers and hydrophobicity contributed to a lesser extent to the modulation of habituation. These results highlight new principles involved in the fundamental process of habituation, notably trigeminality and the physicochemical characteristics associated.
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Talkenberger, Katrin, Elisabetta Ada Cavalcanti-Adam, Anja Voss-Böhme, and Andreas Deutsch. "Amoeboid-mesenchymal migration plasticity promotes invasion only in complex heterogeneous microenvironments." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-230771.
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During tissue invasion individual tumor cells exhibit two interconvertible migration modes, namely mesenchymal and amoeboid migration. The cellular microenvironment triggers the switch between both modes, thereby allowing adaptation to dynamic conditions. It is, however, unclear if this amoeboid-mesenchymal migration plasticity contributes to a more effective tumor invasion. We address this question with a mathematical model, where the amoeboid-mesenchymal migration plasticity is regulated in response to local extracellular matrix resistance. Our numerical analysis reveals that extracellular matrix structure and presence of a chemotactic gradient are key determinants of the model behavior. Only in complex microenvironments, if the extracellular matrix is highly heterogeneous and a chemotactic gradient directs migration, the amoeboid-mesenchymal migration plasticity allows a more widespread invasion compared to the non-switching amoeboid and mesenchymal modes. Importantly, these specific conditions are characteristic for in vivo tumor invasion. Thus, our study suggests that in vitro systems aiming at unraveling the underlying molecular mechanisms of tumor invasion should take into account the complexity of the microenvironment by considering the combined effects of structural heterogeneities and chemical gradients on cell migration.
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Poletti, Sophia C., Annachiara Cavazzana, Cagdas Guducu, Maria Larsson, and Thomas Hummel. "Indistinguishable odour enantiomers: Differences between peripheral and central-nervous electrophysiological responses." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-230788.
Full textAbstract:
The ability of humans to discriminate enantiomeric odour pairs is substance –specific. Current literature suggests that psychophysical discrimination of odour enantiomers mainly depends on the peripheral processing at the level of the olfactory sensory neurons (OSN). To study the influence of central processing in discrimination, we investigated differences in the electrophysiological responses to psychophysically indistinguishable (+)- and (−)- rose oxide enantiomers at peripheral and central-nervous levels in humans. We recorded the electro-olfactogram (EOG) from the olfactory epithelium and the EEG-derived olfactory event-related potentials (OERP). Results from a psychophysical three alternative forced choice test indicated indistinguishability of the two odour enantiomers. In a total of 19 young participants EOG could be recorded in 74 and OERP in 95% of subjects. Significantly different EOG amplitudes and latencies were recorded in response to the 2 stimuli. However, no such differences in amplitude or latency emerged for the OERP. In conclusion, although the pair of enantiomer could be discriminated at a peripheral level this did not lead to a central-nervous/cognitive differentiation of the two stimuli.
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Rindermann, Heiner, David Becker, and Thomas R. Coyle. "Survey of Expert Opinion on Intelligence: Causes of International Differences in Cognitive Ability Tests." Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-209100.
Full textAbstract:
Following Snyderman and Rothman (1987, 1988), we surveyed expert opinions on the current state of intelligence research. This report examines expert opinions on causes of international differences in student assessment and psychometric IQ test results. Experts were surveyed about the importance of culture, genes, education (quantity and quality), wealth, health, geography, climate, politics, modernization, sampling error, test knowledge, discrimination, test bias, and migration. The importance of these factors was evaluated for diverse countries, regions, and groups including Finland, East Asia, sub-Saharan Africa, Southern Europe, the Arabian-Muslim world, Latin America, Israel, Jews in the West, Roma (gypsies), and Muslim immigrants. Education was rated by N = 71 experts as the most important cause of international ability differences. Genes were rated as the second most relevant factor but also had the highest variability in ratings. Culture, health, wealth, modernization, and politics were the next most important factors, whereas other factors such as geography, climate, test bias, and sampling error were less important. The paper concludes with a discussion of limitations of the survey (e.g., response rates and validity of expert opinions).
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Betzler, Alexander, Soeren Torge Mees, Josefine Pump, Sebastian Schölch, Carolin Zimmermann, Daniela E. Aust, Jürgen Weitz, Thilo Welsch, and Marius Distler. "Clinical impact of duodenal pancreatic heterotopia – Is there a need for surgical treatment?" Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-227082.
Full textAbstract:
Background
Pancreatic heterotopia (PH) is defined as ectopic pancreatic tissue outside the normal pancreas and its vasculature and duct system. Most frequently, PH is detected incidentally by histopathological examination. The aim of the present study was to analyze a large single-center series of duodenal PH with respect to the clinical presentation.
Methods
A prospective pancreatic database was retrospectively analyzed for cases of PH of the duodenum. All pancreatic and duodenal resections performed between January 2000 and October 2015 were included and screened for histopathologically proven duodenal PH. PH was classified according to Heinrich’s classification (Type I acini, ducts, and islet cells; Type II acini and ducts; Type III only ducts).
Results
A total of 1274 pancreatic and duodenal resections were performed within the study period, and 67 cases of PH (5.3%) were identified. The respective patients were predominantly male (72%) and either underwent pancreatoduodenectomy (n = 60); a limited pancreas resection with partial duodenal resection (n = 4); distal pancreatectomy with partial duodenal resection (n = 1); total pancreatectomy (n = 1); or enucleation (n = 1). Whereas 65 patients (83.5%) were asymptomatic, 11 patients (18.4%) presented with symptoms related to PH (most frequently with abdominal pain [72%] and duodenal obstruction [55%]). Of those, seven patients (63.6%) had chronic pancreatitis in the heterotopic pancreas. The risk of malignant transformation into adenocarcinoma was 2.9%.
Conclusions
PH is found in approximately 5% of pancreatic or duodenal resections and is generally asymptomatic. Chronic pancreatitis is not uncommon in heterotopic pancreatic tissue, and even there is a risk of malignant transformation. PH should be considered for the differential diagnosis of duodenal lesions and surgery should be considered, especially in symptomatic cases.
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Baumgaertel, Johanna, Robert Haußmann, Antonia Gruschwitz, Annett Werner, Antje Osterrath, Jan Lange, Katharina L. Donix, Jennifer Linn, and Markus Donix. "Education and Genetic Risk Modulate Hippocampal Structure in Alzheimer’s Disease." Aging and Disease, 2016. https://tud.qucosa.de/id/qucosa%3A29982.
Full textAbstract:
Genetic and environmental protective factors and risks modulate brain structure and function in neurodegenerative diseases and their preclinical stages. We wanted to investigate whether the years of formal education, a proxy measure for cognitive reserve, would influence hippocampal structure in Alzheimer’s disease patients, and whether apolipoprotein Eε4 (APOE4) carrier status and a first-degree family history of the disease would change a possible association. Fifty-eight Alzheimer’s disease patients underwent 3T magnetic resonance imaging. We applied a cortical unfolding approach to investigate individual subregions of the medial temporal lobe. Among patients homozygous for the APOE4 genotype or carrying both APOE4 and family history risks, lower education was associated with a thinner cortex in multiple medial temporal regions, including the hippocampus. Our data suggest that the years of formal education and genetic risks interact in their influence on hippocampal structure in Alzheimer’s disease patients.
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Bon, Volodymyr, Negar Kavoosi, Irena Senkovska, Philipp Müller, Jana Schaber, Dirk Wallacher, Daniel M. Többens, Uwe Mueller, and Stefan Kaskel. "Tuning the flexibility in MOFs by SBU functionalization." Royal Society of Chemistry, 2016. https://tud.qucosa.de/id/qucosa%3A30176.
Full textAbstract:
A new approach for the fine tuning of flexibility in MOFs, involving functionalization of the secondary building unit, is presented. The 'gate pressure' MOF [Zn3(bpydc)2(HCOO)2] was used as a model material and SBU functionalization was performed by using monocarboxylic acids such as acetic, benzoic or cinnamic acids instead of formic acid in the synthesis. The resulting materials are isomorphous to [Zn3(bpydc)2(HCOO)2] in the 'as made' form, but show different structural dynamics during the guest removal. The activated materials have entirely different properties in the nitrogen physisorption experiments clearly showing the tunability of the gate pressure, at which the structural transformation occurs, by using monocarboxylic acids with varying backbone structure in the synthesis. Thus, increasing the number of carbon atoms in the backbone leads to the decreasing gate pressure required to initiate the structural transition. Moreover, in situ adsorption/PXRD data suggest differences in the mechanism of the structural transformations: from 'gate opening' in the case of formic acid to 'breathing' if benzoic acid is used.
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Beintner, Ina, and Corinna Jacobi. "Impact of telephone prompts on the adherence to an Internet-based aftercare program for women with bulimia nervosa: A secondary analysis of data from a randomized controlled trial." Elsevier, 2017. https://tud.qucosa.de/id/qucosa%3A31002.
Full textAbstract:
Introduction
Poor adherence is a common challenge in self-directed mental health interventions. Research findings indicate that telephone prompts may be useful to increase adherence.
Method
Due to poor adherence in a randomized controlled trial evaluating an Internet-based aftercare program for women with bulimia nervosa we implemented regular short telephone prompts into the study protocol halfway through the trial period. Of the 126 women in the intervention group, the first 63 women were not prompted by telephone (unprompted group) and compared with 63 women who subsequently enrolled into the study and were attempted to prompt bimonthly by a research assistant (telephone prompt group). Completed telephone calls took less than 5 min and did not include any symptom-related counseling.
Results
Most of the women in the telephone prompt group (67%) were reached only once or twice during the intervention period. However, overall adherence in the telephone prompt group was significantly higher than in the unprompted group (T = − 3.015, df = 124, p = 0.003).
Conclusion
Our findings from this secondary analysis suggest that telephone prompts can positively affect adherence to an Internet-based aftercare intervention directed at patients with bulimia nervosa.
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Mahfouz, Norhan, Serena Caucci, Eric Achatz, Torsten Semmler, Sebastian Guenther, Thomas U. Berendonk, and Michael Schroeder. "High genomic diversity of multi-drug resistant wastewater Escherichia coli." Nature Publishing Group, 2018. https://tud.qucosa.de/id/qucosa%3A32482.
Full textAbstract:
Wastewater treatment plants play an important role in the emergence of antibiotic resistance. They provide a hot spot for exchange of resistance within and between species. Here, we analyse and quantify the genomic diversity of the indicator Escherichia coli in a German wastewater treatment plant and we relate it to isolates’ antibiotic resistance. Our results show a surprisingly large pan-genome, which mirrors how rich an environment a treatment plant is. We link the genomic analysis to a phenotypic resistance screen and pinpoint genomic hot spots, which correlate with a resistance phenotype. Besides well-known resistance genes, this forward genomics approach generates many novel genes, which correlated with resistance and which are partly completely unknown. A surprising overall finding of our analyses is that we do not see any difference in resistance and pan genome size between isolates taken from the inflow of the treatment plant and from the outflow. This means that while treatment plants reduce the amount of bacteria released into the environment, they do not reduce the potential for antibiotic resistance of these bacteria.
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Elsner, Bernhard, Simon Schweder, and Jan Mehrholz. "Immediate effects of rest periods on balance control in patients after stroke. A randomized controlled pilot trial." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-236947.
Full textAbstract:
Objectives
This randomized controlled trial evaluates the effects of two different rest periods between as set of balance exercises after stroke during inpatient rehabilitation.
Results
Twenty patients after stroke [11 males; mean (SD) age 65.4 (11.5) years; duration of illness 5.3 (3.4) weeks; 16 (80%) left-sided strokes] were randomly allocated into two groups of either a full rest (FR) of 4 min (n = 10) or a short rest (SR) of 1 min between exercise sets (n = 10). Patients improved from baseline until immediately after exercises in one-leg standing time on the affected leg [SR: mean difference 5.1 s (SD 10.3) and FR: 2.0 s (2.4)] and tandem standing time (TST). [SR: 14.9 s (SD 24.6) and FR: 5.7 s (12.0)], but OLST and TST did not differ significantly between groups (p = 0.35 and p = 0.52, respectively).
Trial registration The study was registered retrospectively in the German Register of Clinical Trials with the ID: DRKS00013979
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Thieme, Sebastian, Alexander Holzbaur, Ralf Wiedemuth, Aline Binner, Katrin Navratiel, Konstantinos Anastassiadis, Sebastian Brenner, and Cornelia Richter. "The Dox-pDC - A murine conditionally immortalized plasmacytoid dendritic cell line with native immune profile." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-234947.
Full textAbstract:
Plasmacytoid dendritic cells (pDC) constitute a very rare blood cell population and play a significant role in immune response and immune-mediated disorders. Investigations on primary pDCs are hindered not only due to their rarity but also because they represent a heterogeneous cell population which is difficult to culture ex vivo. We generated a conditionally immortalized pDC line (Dox-pDC) from mice with Doxycycline-inducible SV40 Large T Antigen with a comparable immune profile to primary pDCs. The Dox-pDC secrete pro- and anti-inflammatory cytokines upon Toll-like receptor 9 stimulation and upregulate their MHCI, MHCII and costimulatory molecules. Further, the Dox-pDC activate and polarize naïve T cells in vivo and in vitro in response to the model antigen Ovalbumin. Due to their long-term culture stability and their robust proliferation Dox-pDC represent a reliable alternative to primary mouse pDC.
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Kiebist, Jan, Kai-Uwe Schmidtke, Jörg Zimmermann, Harald Kellner, Nico Jehmlich, René Ullrich, Daniel Zänder, Martin Hofrichter, and Katrin Scheibner. "A peroxygenase from Chaetomium globosum catalyzes the selective oxygenation of testosterone." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-222847.
Full textAbstract:
Unspecific peroxygenases (UPO, EC 1.11.2.1) secreted by fungi open an efficient way to selectively oxyfunctionalize diverse organic substrates, including less-activated hydrocarbons, by transferring peroxide-borne oxygen. We investigated a cell-free approach to incorporate epoxy and hydroxyl functionalities directly into the bulky molecule testosterone by a novel unspecific peroxygenase (UPO) that is produced by the ascomycetous fungus Chaetomium globosum in a complex medium rich in carbon and nitrogen. Purification by fast protein liquid chromatography revealed two enzyme fractions with the same molecular mass (36 kDa) and with specific activity of 4.4 to 12 U mg−1. Although the well-known UPOs of Agrocybe aegerita (AaeUPO) and Marasmius rotula (MroUPO) failed to convert testosterone in a comparative study, the UPO of C. globosum (CglUPO) accepted testosterone as substrate and converted it with total turnover number (TTN) of up to 7000 into two oxygenated products: the 4,5-epoxide of testosterone in β-configuration and 16α-hydroxytestosterone. The reaction performed on a 100 mg scale resulted in the formation of about 90 % of the epoxide and 10 % of the hydroxylation product, both of which could be isolated with purities above 96 %. Thus, CglUPO is a promising biocatalyst for the oxyfunctionalization of bulky steroids and it will be a useful tool for the synthesis of pharmaceutically relevant steroidal molecules.
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Bluschke, Annet, der Hagen Maja von, Katharina Papenhagen, Veit Roessner, and Christian Beste. "Response inhibition in Attention deficit disorder and neurofibromatosis type 1 – clinically similar, neurophysiologically different." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-230159.
Full textAbstract:
There are large overlaps in cognitive deficits occurring in attention deficit disorder (ADD) and neurodevelopmental disorders like neurofibromatosis type 1 (NF1). This overlap is mostly based on clinical measures and not on in-depth analyses of neuronal mechanisms. However, the consideration of such neuronal underpinnings is crucial when aiming to integrate measures that can lead to a better understanding of the underlying mechanisms. Inhibitory control deficits, for example, are a hallmark in ADD, but it is unclear how far there are similar deficits in NF1. We thus compared adolescent ADD and NF1 patients to healthy controls in a Go/Nogo task using behavioural and neurophysiological measures. Clinical measures of ADD-symptoms were not different between ADD and NF1. Only patients with ADD showed increased Nogo errors and reductions in components reflecting response inhibition (i.e. Nogo-P3). Early perceptual processes (P1) were changed in ADD and NF1. Clinically, patients with ADD and NF1 thus show strong similarities. This is not the case in regard to underlying cognitive control processes. This shows that in-depth analyses of neurophysiological processes are needed to determine whether the overlap between ADD and NF1 is as strong as assumed and to develop appropriate treatment strategies.
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Schuller, Astrid, Gerhard Rödel, and Kai Ostermann. "Tuning the Sensitivity of the PDR5 Promoter-Based Detection of Diclofenac in Yeast Biosensors." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-230652.
Full textAbstract:
The commonly used drug diclofenac is an important environmental anthropogenic pollutant. Currently, detection of diclofenac is mainly based on chemical and physical methods. Here we describe a yeast biosensor that drives the diclofenac-dependent expression of a recombinant fluorescent protein from the authentic promoter of the PDR5 gene. This key component of the pleiotropic drug response encodes a multidrug transporter that is involved in cellular detoxification. We analyse the effects on diclofenac sensitivity of artificial PDR5 promoter derivatives in wild-type and various yeast mutant strains. This approach enabled us to generate sensor strains with elevated drug sensitivity.
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Vetter, Nora C., Julius Steding, Sarah Jurk, Stephan Ripke, Eva Mennigen, and Michael N. Smolka. "Reliability in adolescent fMRI within two years – a comparison of three tasks." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-230621.
Full textAbstract:
Longitudinal developmental fMRI studies just recently began to focus on within-subject reliability using the intraclass coefficient (ICC). It remains largely unclear which degree of reliability can be achieved in developmental studies and whether this depends on the type of task used. Therefore, we aimed to systematically investigate the reliability of three well-classified tasks: an emotional attention, a cognitive control, and an intertemporal choice paradigm. We hypothesized to find higher reliability in the cognitive task than in the emotional or reward-related task. 104 healthy mid-adolescents were scanned at age 14 and again at age 16 within M = 1.8 years using the same paradigms, scanner, and scanning protocols. Overall, we found both variability and stability (i.e. poor to excellent ICCs) depending largely on the region of interest (ROI) and task. Contrary to our hypothesis, whole brain reliability was fair for the cognitive control task but good for the emotional attention and intertemporal choice task. Subcortical ROIs (ventral striatum, amygdala) resulted in lower ICCs than visual ROIs. Current results add to the yet sparse overall ICC literature in both developing samples and adults. This study shows that analyses of stability, i.e. reliability, are helpful benchmarks for longitudinal studies and their implications for adolescent development.
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Mwangi, Hosea M., Padia Lariu, Stefan Julich, Sopan D. Patil, Morag A. McDonald, and Karl-Heinz Feger. "Characterizing the Intensity and Dynamics of Land-Use Change in the Mara River Basin, East Africa." Molecular Diversity Preservation International MDPI, 2017. https://tud.qucosa.de/id/qucosa%3A30819.
Full textAbstract:
The objective of this study was to analyze patterns, dynamics and processes of land-use/cover changes in the transboundary Mara River Basin in East Africa. We specifically focused on deforestation and expansion of agriculture in the watershed. The intensity analysis approach was used to analyze data from satellite imagery-derived land-use/cover maps. Results indicate that swap change accounted for more than 50% of the overall change, which shows a very dynamic landscape transformation. Transition from closed forest to open forest was found to be a dominant landscape change, as opposed to a random change. Similarly, transition from open forest to small-scale agriculture was also found to be a dominant transition. This suggests a trend (pathway) of deforestation from closed forest to small-scale agriculture, with open forest as a transitional land cover. The observed deforestation may be attributed to continuous encroachment and a series of excisions of the forest reserve. Transition from rangeland to mechanized agriculture was found to be a dominant land-use change, which was attributed to change in land tenure. These findings are crucial for designing strategies and integrated watershed management policies to arrest further deforestation in the forest reserves as well as to sustainably control expansion of agriculture.
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Marxen, Michael, Mark J. Jacob, Dirk K. Müller, Stefan Posse, Elena Ackley, Lydia Hellrung, Philipp Riedel, Stephan Bender, Robert Epple, and Michael N. Smolka. "Amygdala Regulation Following fMRI-Neurofeedback without Instructed Strategies." Frontiers Research Foundation, 2016. https://tud.qucosa.de/id/qucosa%3A29970.
Full textAbstract:
Within the field of functional magnetic resonance imaging (fMRI) neurofeedback, most studies provide subjects with instructions or suggest strategies to regulate a particular brain area, while other neuro-/biofeedback approaches often do not. This study is the first to investigate the hypothesis that subjects are able to utilize fMRI neurofeedback to learn to differentially modulate the fMRI signal from the bilateral amygdala congruent with the prescribed regulation direction without an instructed or suggested strategy and apply what they learned even when feedback is no longer available. Thirty-two subjects were included in the analysis. Data were collected at 3 Tesla using blood oxygenation level dependent (BOLD)-sensitivity optimized multi-echo EPI. Based on the mean contrast between up- and down-regulation in the amygdala in a post-training scan without feedback following three neurofeedback sessions, subjects were able to regulate their amygdala congruent with the prescribed directions with a moderate effect size of Cohen’s d = 0.43 (95% conf. int. 0.23–0.64). This effect size would be reduced, however, through stricter exclusion criteria for subjects that show alterations in respiration. Regulation capacity was positively correlated with subjective arousal ratings and negatively correlated with agreeableness and susceptibility to anger. A learning effect over the training sessions was only observed with end-of-block feedback (EoBF) but not with continuous feedback (trend). The results confirm the above hypothesis. Further studies are needed to compare effect sizes of regulation capacity for approaches with and without instructed strategies.
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Riedel, Philipp, Mark J. Jacob, Dirk K. Müller, Nora C. Vetter, Michael N. Smolka, and Michael Marxen. "Amygdala fMRI Signal as a Predictor of Reaction Time." Frontiers Research Foundation, 2016. https://tud.qucosa.de/id/qucosa%3A29972.
Full textAbstract:
Reaction times (RTs) are a valuable measure for assessing cognitive processes. However, RTs are susceptible to confounds and therefore variable. Exposure to threat, for example, speeds up or slows down responses. Distinct task types to some extent account for differential effects of threat on RTs. But also do inter-individual differences like trait anxiety. In this functional magnetic resonance imaging (fMRI) study, we investigated whether activation within the amygdala, a brain region closely linked to the processing of threat, may also function as a predictor of RTs, similar to trait anxiety scores. After threat conditioning by means of aversive electric shocks, 45 participants performed a choice RT task during alternating 30 s blocks in the presence of the threat conditioned stimulus [CS+] or of the safe control stimulus [CS-]. Trait anxiety was assessed with the State-Trait Anxiety Inventory and participants were median split into a high- and a low-anxiety subgroup. We tested three hypotheses: (1) RTs will be faster during the exposure to threat compared to the safe condition in individuals with high trait anxiety. (2) The amygdala fMRI signal will be higher in the threat condition compared to the safe condition. (3) Amygdala fMRI signal prior to a RT trial will be correlated with the corresponding RT. We found that, the high-anxious subgroup showed faster responses in the threat condition compared to the safe condition, while the low-anxious subgroup showed no significant difference in RTs in the threat condition compared to the safe condition. Though the fMRI analysis did not reveal an effect of condition on amygdala activity, we found a trial-by-trial correlation between blood-oxygen-level-dependent signal within the right amygdala prior to the CRT task and the subsequent RT. Taken together, the results of this study showed that exposure to threat modulates task performance. This modulation is influenced by personality trait. Additionally and most importantly, activation in the amygdala predicts behavior in a simple task that is performed during the exposure to threat. This finding is in line with “attentional capture by threat”—a model that includes the amygdala as a key brain region for the process that causes the response slowing.
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Busse, Patricia, Corina Vater, Maik Stiehler, Jörg Nowotny, Philip Kasten, Henriette Bretschneider, Stuart B. Goodman, Michael Gelinsky, and Stefan Zwingenberger. "Cytotoxicity of drugs injected into joints in orthopaedics." British Editorial Soc. of Bone & Joint Surgery, 2019. https://tud.qucosa.de/id/qucosa%3A33832.
Full textAbstract:
Objectives
Intra-articular injections of local anaesthetics (LA), glucocorticoids (GC), or hyaluronic acid (HA) are used to treat osteoarthritis (OA). Contrast agents (CA) are needed to prove successful intra-articular injection or aspiration, or to visualize articular structures dynamically during fluoroscopy. Tranexamic acid (TA) is used to control haemostasis and prevent excessive intra-articular bleeding. Despite their common usage, little is known about the cytotoxicity of common drugs injected into joints. Thus, the aim of our study was to investigate the effects of LA, GC, HA, CA, and TA on the viability of primary human chondrocytes and tenocytes in vitro.
Methods
Human chondrocytes and tenocytes were cultured in a medium with three different drug dilutions (1:2; 1:10; 1:100). The following drugs were used to investigate cytotoxicity: lidocaine hydrochloride 1%; bupivacaine 0.5%; triamcinolone acetonide; dexamethasone 21-palmitate; TA; iodine contrast media; HA; and distilled water. Normal saline served as a control. After an incubation period of 24 hours, cell numbers and morphology were assessed.
Results
Using LA or GC, especially triamcinolone acetonide, a dilution of 1:100 resulted in only a moderate reduction of viability, while a dilution of 1:10 showed significantly fewer cell counts. TA and CA reduced viability significantly at a dilution of 1:2. Higher dilutions did not affect viability. Notably, HA showed no effects of cytotoxicity in all drug dilutions.
Conclusion
The toxicity of common intra-articular injectable drugs, assessed by cell viability, is mainly dependent on the dilution of the drug being tested. LA are particularly toxic, whereas HA did not affect cell viability.
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Muscoloni, Alessandro, and Carlo Vittorio Cannistraci. "A nonuniform popularity-similarity optimization (nPSO) model to efficiently generate realistic complex networks with communities." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-236957.
Full textAbstract:
The investigation of the hidden metric space behind complex network topologies is a fervid topic in current network science and the hyperbolic space is one of the most studied, because it seems associated to the structural organization of many real complex systems. The popularity-similarity-optimization (PSO) model simulates how random geometric graphs grow in the hyperbolic space, generating realistic networks with clustering, small-worldness, scale-freeness and rich-clubness. However, it misses to reproduce an important feature of real complex networks, which is the community organization. The geometrical-preferential-attachment (GPA) model was recently developed in order to confer to the PSO also a soft community structure, which is obtained by forcing different angular regions of the hyperbolic disk to have a variable level of attractiveness. However, the number and size of the communities cannot be explicitly controlled in the GPA, which is a clear limitation for real applications. Here, we introduce the nonuniform PSO (nPSO) model. Differently from GPA, the nPSO generates synthetic networks in the hyperbolic space where heterogeneous angular node attractiveness is forced by sampling the angular coordinates from a tailored nonuniform probability distribution (for instance a mixture of Gaussians). The nPSO differs from GPA in other three aspects: it allows one to explicitly fix the number and size of communities; it allows one to tune their mixing property by means of the network temperature; it is efficient to generate networks with high clustering. Several tests on the detectability of the community structure in nPSO synthetic networks and wide investigations on their structural properties confirm that the nPSO is a valid and efficient model to generate realistic complex networks with communities.
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Niemann, Claudia, Ben Godde, and Claudia Voelcker-Rehage. "Senior Dance Experience, Cognitive Performance, and Brain Volume in Older Women." Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-211789.
Full textAbstract:
Physical activity is positively related to cognitive functioning and brain volume in older adults. Interestingly, different types of physical activity vary in their effects on cognition and on the brain. For example, dancing has become an interesting topic in aging research, as it is a popular leisure activity among older adults, involving cardiovascular and motor fitness dimensions that can be positively related to cognition. However, studies on brain structure are missing. In this study, we tested the association of long-term senior dance experience with cognitive performance and gray matter brain volume in older women aged 65 to 82 years. We compared nonprofessional senior dancers (n=28) with nonsedentary control group participants without any dancing experience (n=29), who were similar in age, education, IQ score, lifestyle and health factors, and fitness level. Differences neither in the four tested cognitive domains (executive control, perceptual speed, episodic memory, and long-term memory) nor in brain volume (VBM whole-brain analysis, region-of-interest analysis of the hippocampus) were observed. Results indicate that moderate dancing activity (1-2 times per week, on average) has no additional effects on gray matter volume and cognitive functioning when a certain lifestyle or physical activity and fitness level are reached.
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Dumke, Roger, and Enno Jacobs. "Antibody response to Mycoplasma pneumoniae: protection of host and influence on outbreaks?" Frontiers Media, 2016. https://tud.qucosa.de/id/qucosa%3A29946.
Full textAbstract:
In humans of all ages, the cell wall-less and genome-reduced species Mycoplasma pneumoniae can cause infections of the upper and lower respiratory tract. The well-documented occurrence of major peaks in the incidence of community-acquired pneumonia cases reported world-wide, the multifaceted clinical manifestations of infection and the increasing number of resistant strains provide reasons for ongoing interest in the pathogenesis of mycoplasmal disease. The results of recent studies have provided insights into the interaction of the limited virulence factors of the bacterium with its host. In addition, the availability of complete M. pneumoniae genomes from patient isolates and the development of proteomic methods for investigation of mycoplasmas have not only allowed characterization of sequence divergences between strains but have also shown the importance of proteins and protein parts for induction of the immune reaction after infection. This review focuses on selected aspects of the humoral host immune response as a factor that might influence the clinical course of infections, subsequent protection in cases of re-infections and changes of epidemiological pattern of infections. The characterization of antibodies directed to defined antigens and approaches to promote their induction in the respiratory mucosa are also preconditions for the development of a vaccine to protect risk populations from severe disease due to M. pneumoniae.
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Wiedmer, Stefanie, Alexander Erdbeer, Beate Volke, Stephanie Randel, Franz Kapplusch, Sacha Hanig, and Michael Kurth. "Identification and analysis of Eimeria nieschulzi gametocyte genes reveal splicing events of gam genes and conserved motifs in the wall-forming proteins within the genus Eimeria (Coccidia, Apicomplexa)." EDP Sciences, 2017. https://tud.qucosa.de/id/qucosa%3A30707.
Full textAbstract:
The genus Eimeria (Apicomplexa, Coccidia) provides a wide range of different species with different hosts to study common and variable features within the genus and its species. A common characteristic of all known Eimeria species is the oocyst, the infectious stage where its life cycle starts and ends. In our study, we utilized Eimeria nieschulzi as a model organism. This rat-specific parasite has complex oocyst morphology and can be transfected and even cultivated in vitro up to the oocyst stage. We wanted to elucidate how the known oocyst wall-forming proteins are preserved in this rodent Eimeria species compared to other Eimeria. In newly obtained genomics data, we were able to identify different gametocyte genes that are orthologous to already known gam genes involved in the oocyst wall formation of avian Eimeria species. These genes appeared putatively as single exon genes, but cDNA analysis showed alternative splicing events in the transcripts. The analysis of the translated sequence revealed different conserved motifs but also dissimilar regions in GAM proteins, as well as polymorphic regions. The occurrence of an underrepresented gam56 gene version suggests the existence of a second distinct E. nieschulzi genotype within the E. nieschulzi Landers isolate that we maintain.
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Lautenschläger, Thea, Andreas Kempe, Christoph Neinhuis, André Wagenführ, and Sebastian Siwek. "Not Only Delicious: Papaya Bast Fibres in Biocomposites." NC State University, 2016. https://tud.qucosa.de/id/qucosa%3A30117.
Full textAbstract:
Previous studies have shown favourable properties for papaya bast fibres, with a Young's modulus of up to 10 GPa and a tensile strength of up to 100 MPa. Because the fibres remain as residues on papaya plantations across the tropics in large quantities, their use in the making of green composites would seem to be worthy of consideration. This study aims to show that such composites can have very suitable mechanical properties, comparable to or even better than the common wood plastic composites (WPCs), and as such, represent a promising raw material for composites and a low-cost alternative to wood.
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Liu, Lanfa, Min Ji, and Manfred F. Buchroithner. "Combining Partial Least Squares and the Gradient-Boosting Method for Soil Property Retrieval Using Visible Near-Infrared Shortwave Infrared Spectra." Molecular Diversity Preservation International (MDPI), 2017. https://tud.qucosa.de/id/qucosa%3A30734.
Full textAbstract:
Soil spectroscopy has experienced a tremendous increase in soil property characterisation, and can be used not only in the laboratory but also from the space (imaging spectroscopy). Partial least squares (PLS) regression is one of the most common approaches for the calibration of soil properties using soil spectra. Besides functioning as a calibration method, PLS can also be used as a dimension reduction tool, which has scarcely been studied in soil spectroscopy. PLS components retained from high-dimensional spectral data can further be explored with the gradient-boosted decision tree (GBDT) method. Three soil sample categories were extracted from the Land Use/Land Cover Area Frame Survey (LUCAS) soil library according to the type of land cover (woodland, grassland, and cropland). First, PLS regression and GBDT were separately applied to build the spectroscopic models for soil organic carbon (OC), total nitrogen content (N), and clay for each soil category. Then, PLS-derived components were used as input variables for the GBDT model. The results demonstrate that the combined PLS-GBDT approach has better performance than PLS or GBDT alone. The relative important variables for soil property estimation revealed by the proposed method demonstrated that the PLS method is a useful dimension reduction tool for soil spectra to retain target-related information.
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Schmieder, Felix, Simon D. Klapper, Nektarios Koukourakis, Volker Busskamp, and Jürgen W. Czarske. "Optogenetic Stimulation of Human Neural Networks Using Fast Ferroelectric Spatial Light Modulator—Based Holographic Illumination." Molecular Diversity Preservation International (MDPI), 2018. https://tud.qucosa.de/id/qucosa%3A32582.
Full textAbstract:
The generation and application of human stem-cell-derived functional neural circuits promises novel insights into neurodegenerative diseases. These networks are often studied using stem-cell derived random neural networks in vitro, with electrical stimulation and recording using multielectrode arrays. However, the impulse response function of networks is best obtained with spatiotemporally well-defined stimuli, which electrical stimulation does not provide. Optogenetics allows for the functional control of genetically altered cells with light stimuli at high spatiotemporal resolution. Current optogenetic investigations of neural networks are often conducted using full field illumination, potentially masking important functional information. This can be avoided using holographically shaped illumination. In this article, we present a digital holographic illumination setup with a spatial resolution of about 8 µm, which suffices for the stimulation of single neurons, and offers a temporal resolution of less than 0.6 ms. With this setup, we present preliminary single-cell stimulation recording of stem-cell derived induced human neurons in a random neural network. This will offer the opportunity for further studies on connectivity in such networks.
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Böhm, Robert, Mike Thieme, Daniel Wohlfahrt, Daniel Sebastian Wolz, Benjamin Richter, and Hubert Jäger. "Reinforcement Systems for Carbon Concrete Composites Based on Low-Cost Carbon Fibers." Molecular Diversity Preservation International MDPI, 2018. https://tud.qucosa.de/id/qucosa%3A33323.
Full textAbstract:
Carbon concrete polyacrylonitrile (PAN)/lignin-based carbon fiber (CF) composites are a new promising material class for the building industry. The replacement of the traditional heavy and corroding steel reinforcement by carbon fiber (CF)-based reinforcements offers many significant advantages: a higher protection of environmental resources because of lower CO2 consumption during cement production, a longer lifecycle and thus, much less damage to structural components and a higher degree of design freedom because lightweight solutions can be realized. However, due to cost pressure in civil engineering, completely new process chains are required to manufacture CF-based reinforcement structures for concrete. This article describes the necessary process steps in order to develop CF reinforcement: (1) the production of cost-effective CF using novel carbon fiber lines, and (2) the fabrication of CF rebars with different geometry profiles. It was found that PAN/lignin-based CF is currently the promising material with the most promise to meet future market demands. However, significant research needs to be undertaken in order to improve the properties of lignin-based and PAN/lignin-based CF, respectively. The CF can be manufactured to CF-based rebars using different manufacturing technologies which are developed at a prototype level in this study.
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Beintner, Ina, and Corinna Jacobi. "Internet-based aftercare for women with bulimia nervosa following inpatient treatment: The role of adherence." Elsevier, 2019. https://tud.qucosa.de/id/qucosa%3A33834.
Full textAbstract:
Facing poor long-term outcome and high relapse rates in the treatment of bulimia nervosa, we developed an Internet-based aftercare program for women with severe and chronic bulimia nervosa following inpatient treatment based on previous experiences with self-directed targeted prevention and early intervention programs delivered online. The aim of the present study was to examine adherence to the program in detail, to explore potential variables that predict adherence and to analyze whether adherence affects outcomes. We analyzed data
from 126 women in the intervention group of a randomized controlled trial. 107 women (85%) logged on to the program platform at least once. These women opened on average 42.8% (SD=31.9%) of all assigned program pages. Adherence declined during the course of the intervention. Adherence was not associated with the number of outpatient treatment sessions received during the intervention period. Adherence was not related to overall illness severity or duration at baseline. However, excessive exercise at hospital discharge (which may be a sign of
insufficient motivation to change eating disorder related behaviors) seems to play some small role in adherence. Adherence did not affect intervention outcomes. Based on our findings, we would like to advocate further research on online aftercare interventions for women with severe and chronic bulimia nervosa.
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Spieth, Peter Markus, Anne Sophie Kubasch, Ana Isabel Penzlin, Ben Min-Woo Illigens, Kristian Barlinn, and Timo Siepmann. "Randomized controlled trials - a matter of design." Dove Medical Press, 2016. https://tud.qucosa.de/id/qucosa%3A29007.
Full textAbstract:
Randomized controlled trials (RCTs) are the hallmark of evidence-based medicine and form the basis for translating research data into clinical practice. This review summarizes commonly applied designs and quality indicators of RCTs to provide guidance in interpreting and critically evaluating clinical research data. It further reflects on the principle of equipoise and its practical applicability to clinical science with an emphasis on critical care and neurological research. We performed a review of educational material, review articles, methodological studies, and published clinical trials using the databases MEDLINE, PubMed, and ClinicalTrials.gov. The most relevant recommendations regarding design, conduction, and reporting of RCTs may include the following: 1) clinically relevant end points should be defined a priori, and an unbiased analysis and report of the study results should be warranted, 2) both significant and nonsignificant results should be objectively reported and published, 3) structured study design and performance as indicated in the Consolidated Standards of Reporting Trials statement should be employed as well as registration in a public trial database, 4) potential conflicts of interest and funding sources should be disclaimed in study report or publication, and 5) in the comparison of experimental treatment with standard care, preplanned interim analyses during an ongoing RCT can aid in maintaining clinical equipoise by assessing benefit, harm, or futility, thus allowing decision on continuation or termination of the trial.
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Fediai, Artem, Dmitry A. Ryndyk, Gotthard Seifert, Sven Mothes, Martin Claus, Michael Schröter, and Gianaurelio Cuniberti. "Towards an optimal contact metal for CNTFETs." Royal Society of Chemistry, 2016. https://tud.qucosa.de/id/qucosa%3A30077.
Full textAbstract:
Downscaling of the contact length Lc of a side-contacted carbon nanotube field-effect transistor (CNTFET) is challenging because of the rapidly increasing contact resistance as Lc falls below 20–50 nm. If in agreement with existing experimental results, theoretical work might answer the question, which metals yield the lowest CNT–metal contact resistance and what physical mechanisms govern the geometry dependence of the contact resistance. However, at the scale of 10 nm, parameter-free models of electron transport become computationally prohibitively expensive. In our work we used a dedicated combination of the Green function formalism and density functional theory to perform an overall ab initio simulation of extended CNT–metal contacts of an arbitrary length (including infinite), a previously not achievable level of simulations. We provide a systematic and comprehensive discussion of metal–CNT contact properties as a function of the metal type and the contact length. We have found and been able to explain very uncommon relations between chemical, physical and electrical properties observed in CNT–metal contacts. The calculated electrical characteristics are in reasonable quantitative agreement and exhibit similar trends as the latest experimental data in terms of: (i) contact resistance for Lc = ∞, (ii) scaling of contact resistance Rc(Lc); (iii) metal-defined polarity of a CNTFET. Our results can guide technology development and contact material selection for downscaling the length of side-contacts below 10 nm.